2024-03-29T08:19:08Zhttp://nur.nu.edu.kz/oai/requestoai:nur.nu.edu.kz:123456789/8332018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
Investigation of using sulfur-containing gases in low-temperature fuel cell at sulfuric acid production site
Duysebaev, B.
Abramov, A.
Berstenev, S.
Ryspanov, N.
Sokolov, A.Y.
Shkolnik, V.
Umirov, N.
Bakenov, Zhumabay
hydrogen sulfide
sulfur dioxide
technological processes
energy consumption
fuel cell oxidation
electric energy
The possibility and effectiveness of using sulfur dioxide and hydrogen sulfide as the fuel in lowtemperature
fuel cells at the sulfuric acid production site has been investigated. A fuel cell has been designed
and constructed using palladium as a catalyst, which enables conversion of the energy of oxidation of sulfur
dioxide and hydrogen sulfide to the electric energy. The experimental data showed that the use of hydrogen
sulfide and sulfur dioxide as a fuel allows achieving the power of 1.0 and 0.5 mW, respectively. The
comparative studies with the use of hydrogen in the same fuel cell resulted in the power of about 2.0 mW,
i.e. the use of hydrogen sulfide delivers a performance comparable with that of the hydrogen. The processes
of oxidizing of the sulfur containing gases are used in our company in production of sulfuric acid. Oxidation
of these gases conducted using the conventional technological processes. The use of these processes to
produce energy as a byproduct could be an attractive way to reduce the energy consumption of the whole
process. Considering the relatively high power obtained in this work for the sulfur containing gases fed fuel
cells, the substitution of conventional oxidation of sulfur containing gases in this technological chain by the
fuel cell oxidation, and by-producing the electric energy, could be very profitable for the energy efficiency
enhancement of the main production process. In the future work, the design and development of fuel cell
catalysts and membranes to enhance the performances of sulfur containing fuel cells will be significant.
2015-12-02
2015-12-02
2014
Article
Duysebaev B., Abramov A., Berstenev S., Ryspanov N., Sokolov A.Y., Shkolnik V., Umirov N., Bakenov Z., 2014, Investigation of using sulfur-containing gases in low-temperature fuel cell at sulfuric acid production site, Eurasian Chemico-Technological Journal 16
http://nur.nu.edu.kz/handle/123456789/833
en
Eurasian Chemico-Technological Journal 16., http://ect-journal.kz/index.php/ect01/article/view/10
oai:nur.nu.edu.kz:123456789/8292018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Torsional current - meter for channels
Zarea, Stefan
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics::Mechanical manufacturing engineering
torsional current-meter
mechanical engineering
The main objective of this paper is to present the results of the experimental investigation of a Zarea-type torsional velocity-meter. For this, a torsional meter was designed, built and tested in the laboratory. The current meter consists of an axial rotor with blades fixed to a shaft which is in turn fixed to a rigid hub. The force of the water flow produces a torque which deforms the shaft. The current meter has been statically calibrated, thereby establishing the variational curve of the torsion angle as a function of the applied torque. A laboratory facility has been constructed in which tests were run for water speeds of up 3m/s. The torque measurements were taken by using strain gauges. The methodology and the equipment used for the experimental evaluation are shown. Additionally illustrated are the calibration curves, the analysis of obtained results, some advantages and disadvantages, and the range of application of the torsional current-meter are all discussed.
2015-12-02
2015-12-02
1997-06-22
Article
http://nur.nu.edu.kz/handle/123456789/829
en
1997 ASME Fluids Engineering Division Summer Meeting, June 22-26
oai:nur.nu.edu.kz:123456789/8302021-02-05T10:25:51Zcom_123456789_79com_123456789_67col_123456789_822
Boundary layer receptivity and resonance caused by tuned disturbances within cascade flows
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
fluid mechanics
The receptivity and stability of steady non-separated and unsteady separated boundary layers in a two-dimensional airfoil cascade flow is investigated by Direct Numerical Simulation of the time-dependent Navier-stokes and continuity equations. The study includes the effects caused by the introduction of free-steam time-harmonic disturbances. The calculation of the transport, generation and dissipation of Fluctuating Kinetic Energy is introduced as a non-classical technique in the analysis
2015-12-02
2015-12-02
1997-05-10
Thesis of the employee
http://nur.nu.edu.kz/handle/123456789/830
en
Nazarbayev University School of Engineering and Digital Sciences
oai:nur.nu.edu.kz:123456789/8312018-08-15T03:49:44Zcom_123456789_79com_123456789_67col_123456789_826
Oscillatory momentum transport in cascade transitional boundary layer flows
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Tollmien-Schlichting waves
The generation and early evolution of boundary layer transitional instabilities, named Tollmien-Schlichting (T-S) waves, in airfoil cascade flows are studied. The energy exchange between the mean flow and the flow instabilities is computed by performing Direct Numerical Simulation of the fluid flow governing equations and by calculating the fluctuating kinetic energy (FKE) budget within the separated boundary layer. The driving role of the FKE production in the wavelength modulation process associated to the receptivity phenomenon, i.e., the generation of T-S waves, is demonstrated. The FKE production largely hastens the wavelength modulation around the inflection point of the mean velocity profile across the boundary layer. Above the inflection point, the fluctuating pressure field favors the energy transport and provides the energy necessary to convect the instabilities out of the boundary layer. The evolution of the T-S waves depicts an asymmetric distribution of the production term in the transverse direction, i.e., in the lower half of the boundary layer the mean flow provides energy to the instabilities while the opposite occurs in the upper half
2015-12-02
2015-12-02
1998
Article
http://nur.nu.edu.kz/handle/123456789/831
en
DOI: 10.2514/6.1998-2560 Conference: 29th AIAA Fluid Dynamics Conference, At Albuquerque, NM, USA, Volume: 1
oai:nur.nu.edu.kz:123456789/8322018-08-15T03:49:43Zcom_123456789_79com_123456789_67col_123456789_826
Effects of external disturbances on the momentum transport in cascade transitional boundary layer flows
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Fluctuating Kinetic Energy
The effects on the boundary layer receptivity in airfoil cascade flow caused by superposed disturbances are studied using an energetic approach. The separated terms in the Fluctuating Kinetic Energy (FKE) budget are calculated. Monotonic time-harmonic disturbances are superposed to the inflow stream using forcing frequencies close to and far from the natural frequency of fluctuation found within the unsteady (supercritical) basic flow. For supercritical regimes, the receptivity is evaluated around the boundary layer separation point, where Tollmien-Schlichting (T-S) waves are naturally generated. For subcritical regimes, the receptivity is explored all over the suction-side of the airfoil since separation does not occur. Within subcritical flows, the superposed perturbation is seen to trigger the generation of T-S-like waves downstream the minimum pressure point only when the forcing frequency is close to n. Within supercritical flows, when the forcing frequency matches n, the FKE budget reflects the energetic interaction between the perturbation and the already existent boundary layer T-S waves
2015-12-02
2015-12-02
1998-06-21
Article
Luis R. Rojas-Solorzano, 1998, Effects of external disturbances on the momentum transport in cascade transitional boundary layer flows, http://nur.nu.edu.kz/handle/123456789/832
http://nur.nu.edu.kz/handle/123456789/832
en
Proceedings of FEDSM’98 1998 ASME Fluids Engineering Division Summer Meeting June 21-25, 1998, Washington, DC
oai:nur.nu.edu.kz:123456789/8372018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
A novel lithium/sulfur battery based on sulfur/graphene nanosheet composite cathode and gel polymer electrolyte
Zhang, Yongguang
Zhao, Yan
Bakenov, Zhumabay
graphene nanosheet
lithium/sulfur battery
nanostructured sulfur cathode
gel polymer electrolyte
silicon dioxide
polymer matrix
A novel sulfur/graphene nanosheet (S/GNS) composite was prepared via a simple ball milling of sulfur with
commercial multi-layer graphene nanosheet, followed by a heat treatment. High-resolution transmission and
scanning electronic microscopy observations showed the formation of irregularly interlaced nanosheet-like structure
consisting of graphene with uniform sulfur coating on its surface. The electrochemical properties of the resulting
composite cathode were investigated in a lithium cell with a gel polymer electrolyte (GPE) prepared by trapping
1 mol dm−3 solution of lithium bistrifluoromethanesulfonamide in tetraethylene glycol dimethyl ether in a polymer
matrix composed of poly(vinylidene fluoride-co-hexafluoropropylene)/poly(methylmethacrylate)/silicon dioxide
(PVDF-HFP/PMMA/SiO2). The GPE battery delivered reversible discharge capacities of 809 and 413 mAh g−1 at the
1st and 50th cycles at 0.2C, respectively, along with a high coulombic efficiency over 50 cycles. This performance
enhancement of the cell was attributed to the suppression of the polysulfide shuttle effect by a collective effect of
S/GNS composite cathode and GPE, providing a higher sulfur utilization.
2015-12-02
2015-12-02
2014
Article
Zhang Yongguang., Zhao Yan., Bakenov Zhumabay., 2014, A novel lithium/sulfur battery based on sulfur/graphene nanosheet composite cathode and gel polymer electrolyte, Nanoscale Research Letters, doi:10.1186/1556-276X-9-137
http://nur.nu.edu.kz/handle/123456789/837
en
Nanoscale Research Letters., http://www.nanoscalereslett.com/content/9/1/137
oai:nur.nu.edu.kz:123456789/8382018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Run Life Enlargement Methodology for Ball-and-Seat Check Valves Used in Artificial Lift Pumping Units
Zarea, S.
Rojas-Solorzano, L.
Kabboul, F.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Ball-and-Seat Check Valves
Experiments are performed to evaluate the leakage vs. pressure drop, wear and fluid properties, in ball-and-seat valves used in pumping units for artificial oil production. The
test facility is constructed to evaluate the operation of several valve sizes, using water, oil and air, subjected to pressure drops up to 5000 psig. Results demonstrated that the currently accepted API vacuum test might be too severe and that more realistic tests may lead to substantial savings in valve replacements. Experimental results in dimensional and
dimensionless form are presented, using a new similitude criterion
2015-12-02
2015-12-02
1999-04-21
Article
Zarea, S., Rojas-Solórzano, Luis Ramon., Kabboul, F., 1999, Run Life Enlargement Methodology for Ball-and-Seat Check Valves Used in Artificial Lift Pumping Units,
http://nur.nu.edu.kz/handle/123456789/838
en
SPE Latin American and Caribbean Petroleum Engineering Conference, Caracas, Venezuela, 21–23 April 1999
oai:nur.nu.edu.kz:123456789/8392018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Fluid flow hydrodynamic modeling in the passage of an oil artificial lift pumping unit
Salazar S., Abraham
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
oil artificial-lift pumping unit
The study of the two-phase flow through the standing and traveling valves used in an oil artificial-lift pumping unit is presented. The investigation aimed to determine the effects the
gaseous phase may cause on the pump volumetric efficiency. Data obtained on a specially designed test facility is presented and analyzed as a first step before developing a semi-empirical model to predict the performance of the pump under two-phase flow conditions. Preliminary results, based on one-phase and two-phase runs, demonstrate important features introduced on the pump performance once the gas-phase is included in the process
2015-12-02
2015-12-02
2000-02-14
Article
Salazar S., Abraham, Rojas-Solórzano, Luis Ramon; 2000, Fluid flow hydrodynamic modeling in the passage of an oil artificial lift pumping unit, http://nur.nu.edu.kz/handle/123456789/839
http://nur.nu.edu.kz/handle/123456789/839
en
Proceeding of ETCE/OMAE2000 Joint Conference Energy for the New Millenium February 14-17, 2000, New Orleans, LA
oai:nur.nu.edu.kz:123456789/8402018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
High mass-loading of sulfur-based cathode composites and polysulfides stabilization for rechargeable lithium/sulfur batteries
Hara, Toru
Konarov, Aishuak
Mentbayeva, Almagul
Kurmanbayeva, Indira
Bakenov, Zhumabay
lithium
sulfur
battery
mass-loading
polysulfide
Although sulfur has a high theoretical gravimetric capacity, 1672 mAh/g, its insulating
nature requires a large amount of conducting additives: this tends to result in a low massloading
of active material (sulfur), and thereby, a lower capacity than expected. Therefore,
an optimal choice of conducting agents and of the method for sulfur/conductingagent
integration is critically important. In this paper, we report that the areal capacity
of 4.9 mAh/cm2 was achieved at sulfur mass loading of 4.1 mg/cm2 by casting sulfur/
polyacrylonitrile/ketjenblack (S/PAN/KB) cathode composite into carbon fiber paper.
This is the highest value among published/reported ones even though it does not contain
expensive nanosized carbon materials such as carbon nanotubes, graphene, or graphene
derivatives, and competitive enough with the conventional LiCoO2-based cathodes (e.g.,
LiCoO2, <20 mg/cm2 corresponding to <2.8 mAh/cm2). Furthermore, the combination
of sulfur/PAN-based composite and PAN-based carbon fiber paper enabled the sulfurbased
composite to be used even in carbonate-based electrolyte solution that many
lithium/sulfur battery researchers avoid the use of it because of severer irreversible active
material loss than in electrolyte solutions without carbonate-based solutions, and even at
the highest mass-loading ever reported (the more sulfur is loaded, the more decomposed
sulfides deposit at an anode surface).
2015-12-02
2015-12-02
2015-05-07
Article
Hara T, Konarov A, Mentbayeva A, Kurmanbayeva I and Bakenov Z (2015) High mass-loading of sulfur-based cathode composites and polysulfides stabilization for rechargeable lithium/sulfur batteries. Front. Energy Res. 3:22. doi: 10.3389/fenrg.2015.00022
http://nur.nu.edu.kz/handle/123456789/840
en
Frontiers in Energy Research., http://journal.frontiersin.org/article/10.3389/fenrg.2015.00022/abstract
oai:nur.nu.edu.kz:123456789/8412018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Numerical simulation of the flow through an intermittent gas lift valve
Concho, Maria A.
Gasbarri, Sandro
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Numerical simulation of the flow
The numerical simulation of the flow through a pilot valve used in the oil intermittent gas lift process is presented.The complexity of the non-isothermal compressible flow is modeled by the solution of the Navier-Stokes, Mass Conservation and Energy equations for the compressible flow. Numerical results and analyses pertaining to the flow dynamics
through a 1½-inch pilot valve at an operating condition encountered in typical field operations are presented
2015-12-02
2015-12-02
2000-02-14
Article
Maria A. Concho, Sandro Gasbarri, Luis R. Rojas-Solórzano; 2000, Numerical simulation of the flow through an intermittent gas lift valve, http://nur.nu.edu.kz/handle/123456789/841
http://nur.nu.edu.kz/handle/123456789/841
en
Proceeding of ETCE/OMAE2000 Joint Conference Energy for the New Millenium February 14-17, 2000, New Orleans, LA
oai:nur.nu.edu.kz:123456789/8422018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Numerical simulation of the heat penetration in two-plate arc welding
Payares, C.
Rojas-Solorzano, L.
Viggiani, P.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
A mathematical model and numerical simulation of the three-dimensional and transient metal arc-welding process is presented. The heat source is considered as spatially distributed following a centered Gaussian bell, while the substract material (Al 6063) is assumed homogeneous and isotropic with temperature-dependent thermal properties. Radiation and convection are also calculated through an empirical temperature dependent correlation. Phase-change phenomenon is included as a discontinuity in the material specific heat. Calculations were performed by using a finite volume code (CFX4.2TM). Computed heat penetration and weld metal area are found to be in good agreement with experimental data.
2015-12-02
2015-12-02
2000
Article
C. Payares, L. Rojas-Solórzano, P. Viggiani., 2000, Numerical simulation of the heat penetration in two-plate arc welding, http://nur.nu.edu.kz/handle/123456789/842
http://nur.nu.edu.kz/handle/123456789/842
en
Conference: h International Congress of Numerical Methods in Engeering and Applied Science (CIMENICS 2000), At Puerto La Cruz, Venezuela, Volume: 5
oai:nur.nu.edu.kz:123456789/8432018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
Carbon/sulfur composite cathodes for flexible lithium/sulfur batteries: status and prospects
Zhao, Yan
Zhang, Yongguang
Bakenova, Zagipa
Bakenov, Zhumabay
lithium/sulfur battery
free-standing cathode
flexible batteries
high-performance batteries
high sulfur loading
High specific energy and low cost flexible lithium/sulfur batteries have attracted significant
attention as a promising power source to enable future flexible and wearable electronic
devices. Here, we review recent progress in the development of free-standing sulfur composite
cathodes, with special emphasis on electrode material selectivity and battery structural
design.The mini-review is organized based on the dimensionality of different scaffold
materials, namely one-dimensional carbon nanotube (CNT), two-dimensional graphene,
and three-dimensional CNT/graphene composite, respectively. Finally, the opportunities
and perspectives of the future research directions are discussed.
2015-12-02
2015-12-02
2015-02-02
Article
Zhao, Yan., Zhang, Yongguang., Bakenova, Zagipa., Bakenov, Zhumabay., Carbon/sulfur composite cathodes for flexible lithium/sulfur batteries: status and prospects, 2015 February 02, Frontiers in Energy Research, doi: 10.3389/fenrg.2015.00002
http://nur.nu.edu.kz/handle/123456789/843
Frontiers in Energy Research., http://journal.frontiersin.org/article/10.3389/fenrg.2015.00002/abstract
oai:nur.nu.edu.kz:123456789/8442018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Design of a flow deflector for an accurate flow meter calibration facility
Corrales-Barallobre, C.
Martínez-Huen, R.
Alvarez, L.
Polanco, G.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
The design and test of a flow deflector gate used for controlling the flow deviation toward the primary tank in a flow-meter calibration facility is presented. The deflector gate is pneumatically controlled and permits the flow conduction to either the suction tank or to the primary tank. The deflector is designed to approximately compensate the flow deficit towards the primary tank during the opening, with the flow excess while in the shutting process. Numerical simulations are performed to study the flow hydrodynamics during the deflector operation. Results are compared to experimental data, and used to improve the gate design. The enhanced design proved to guarantee the uniformity of the flow through the calibration section and the dramatic reduction of the error in volume measurement during calibration.
2015-12-02
2015-12-02
2000-06-11
Article
Corrales-Barallobre, C., Martínez-Huen, R., Alvarez, L., Polanco, G., Rojas-Solórzano, L., 2000, Design of a flow deflector for an accurate flow meter calibration facility, http://nur.nu.edu.kz/handle/123456789/844
http://nur.nu.edu.kz/handle/123456789/844
en
FEDSM2000 FORUM ON FLUID MEASURENMENT AND INTRUMENTATION BOSTON, MASSACHUSETTS, ON JUNE 11-15, 2000
oai:nur.nu.edu.kz:123456789/8452018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
A free-standing sulfur/nitrogen-doped carbon nanotube electrode for high- performance lithium/sulfur batteries
Zhao, Yan
Yin, Fuxing
Zhang, Yongguang
Zhang, Chengwei
Mentbayeva, Almagul
Umirov, Nurzhan
Xie, Hongxian
Bakenov, Zhumabay
lithium/sulfur battery
sulfur/nitrogen-doped carbon nanotube composite cathode
free-standing electrode
A free-standing sulfur/nitrogen-doped carbon nanotube (S/N-CNT) composite prepared via a simple solution
method was first studied as a cathode material for lithium/sulfur batteries. By taking advantage of the self-weaving
behavior of N-CNT, binders and current collectors are rendered unnecessary in the cathode, thereby simplifying its
manufacturing and increasing the sulfur weight ratio in the electrode. Transmission electronic microscopy showed
the formation of a highly developed core-shell tubular structure consisting of S/N-CNT composite with uniform
sulfur coating on the surface of N-CNT. As a core in the composite, the N-CNT with N functionalization provides a
highly conductive and mechanically flexible framework, enhancing the electronic conductivity and consequently
the rate capability of the material.
2015-12-02
2015-12-02
2015-11-19
Article
Zhao Yan., Yin Fuxing., Zhang Yongguang., Zhang Chengwei., Mentbayeva Almagul., Umirov Nurzhan., Xie Hongxian., Bakenov Zhumabay., A free-standing sulfur/Nitrogen-doped carbon nanotube electrode for high- performance lithium/sulfur batteries, 2015 November 19, Nanoscale Research Letters, DOI 10.1186/s11671-015-1152-4
http://nur.nu.edu.kz/handle/123456789/845
Nanoscale Research Letters., http://www.nanoscalereslett.com/content/10/1/450
oai:nur.nu.edu.kz:123456789/8462018-08-15T03:50:25Zcom_123456789_79com_123456789_67col_123456789_826
Design of a large scale flow-meter test and calibration facility
Corrales-Barallobre, C.
Martínez-Huen, R.
Alvarez, Luis
Polanco, G.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
large-scale flowmeter calibration
The design and set up of a large-scale flowmeter calibration and test facility is presented. The facility was designed to handle flowmeters with diameters between 6” and 14”, flow rates up to 0.3 m3/s and to give results less than 1% accurate. The calibration methodology consisted firstly in calibrating the pattern flowmeters, using volume and time primary measurements, and secondly, comparing the pattern to the flowmeters needing calibration. The design and calculation of the primary calibration device is addressed, including numerical simulations of the outflow manifold and the comparison to experimental data. The calibration facility proved to be accurate and reliable in producing renewed calibration data for various tested flowmeters
2015-12-02
2015-12-02
2000-06-11
Article
Corrales-Barallobre, C., Martínez-Huen, R., Alvarez, L., Polanco, G., Rojas-Solórzano, L., 2000, Design of a large scale flow-meter test and calibration facility, http://nur.nu.edu.kz/handle/123456789/846
http://nur.nu.edu.kz/handle/123456789/846
en
FEDSM2000 FORUM ON FLUID MEASURENMENT AND INTRUMENTATION BOSTON, MASSACHUSETTS, ON JUNE 11-15, 2000
oai:nur.nu.edu.kz:123456789/8472018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Design of the distribution manifold for a large-scale flowmeter calibration facility
Corrales-Barallobre, C.
Martínez-Huen, R.
Alvarez, Luis
Polanco, G.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
flowmeter calibration
The design and test of the distribution manifold for a large-scale flowmeter calibration facility is presented. The design was intended to have an air-free flow operation and a free-surface flow-like towards the downstream half-body discharge. Back of the envelope calculations are presented for the estimation of the preliminary dimensions. Numerical simulations of the flow during manifold steady state operation are utilized to refine the manifold design. No air entrapment is noticed in the flow simulation
2015-12-02
2015-12-02
2000-06-11
Article
Corrales-Barallobre, C., Martínez-Huen, R., Alvarez, L., Polanco, G., Rojas-Solórzano, L., 2000,Design of the distribution manifold for a large-scale flowmeter calibration facility, http://nur.nu.edu.kz/handle/123456789/847
http://nur.nu.edu.kz/handle/123456789/847
en
FEDSM2000 FORUM ON FLUID MEASURENMENT AND INSTRUMENTATION BOSTON, MASSACHUSETTS, ON JUNE 11-15, 2000
oai:nur.nu.edu.kz:123456789/8482018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Two-fluid Mixing Enhancement by Using a Static Turbulence Generator
Ortega, P.
McGrath, G.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
The numerical simulation of a static T-type mixer for turbulent mixing of miscible liquids is
reported. The simulation was carried out using CFX, a commercial computational fluid dynamic simulator. The effect of mixing intensification caused by turbulence generators placed downstream of the injection point of the Tee was evaluated in terms of reduction in mixing length for a given mixture quality, uniformity of turbulence intensity and efficiency of energy conversion to useful mixing energy. The mixing quality for an intensified and conventional T-type mixer was compared, and the turbulence generator geometry was optimized. Main stream Reynolds numbers between 50000 and 100000 were considered for additive volume ratios in the range 0.1 - 10%. Selected simulations were validated with experimental data available in the literature for conventional smooth T-type mixers (no ribs). Results were in good agreement with experimental correlations available at high Reynolds numbers. Simulations demonstrated that mixing enhancement was efficient with turbulence generators, extending the Reynolds number range for which compact, low pressure-drop devices may be used for intense mixing. The optimum geometry for turbulence generators was evaluated using criteria based on energetic and spatial efficiency and in all cases the simple Tee was used as the point of reference. Finally, practical design correlations are presented to enable the mixing quality of two miscible streams to be estimated for a simple Tee with and without additional turbulence generators over a range of Reynolds numbers and injection conditions.
2015-12-03
2015-12-03
2001-03-12
Article
Ortega, P., McGrath, G., Rojas-Solórzano L., 2001, Two-fluid Mixing Enhancement by Using a Static Turbulence Generator, http://nur.nu.edu.kz/handle/123456789/848
http://nur.nu.edu.kz/handle/123456789/848
en
SPE International Thermal Operations and Heavy Oil Symposuim, Porlamar, Venezuela, 12–17 March 2001.
oai:nur.nu.edu.kz:123456789/8492018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Study of the transient temperature profiles induced by changes of the welding parameters during aluminium two plate arc butt-welding
Urthaler, Yetzirah
Viggiani, Pedro
Payares, Carolina
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
The numerical study and calculation of transient temperatures developing during the arc-welding process of 6063 T5 aluminum plates is presented. The mathematical model is based on the differential energy conservation equation. The governing equation is solved via numerical simulation using the finite control volume method to obtain the three dimensional and transient temperature profiles induced during the welding process. The moving heat source is considered as represented by a centered Gaussian-Bell distribution, while the base material is assumed to be homogeneous and isotropic with temperature-dependent thermal properties. Radiation and convection are computed and introduced into the model through the boundary conditions as an empirical temperature-dependent correlation. Phase-change phenomenon is included as a discontinuity in the material specific heat. Computed results show the influence of the variation of the welding parameters such as the arc power and welding speed on the computed transient temperatures, penetration and process efficiency
2015-12-04
2015-12-04
2001
Article
Yetzirah Urthaler, Pedro Viggiani, Carolina Payares, Luis Rojas-Solorzano; 2001, Study of the transient temperature profiles induced by changes of the welding parameters during aluminium two plate arc butt-welding, http://nur.nu.edu.kz/handle/123456789/849
http://nur.nu.edu.kz/handle/123456789/849
en
Universidad Simón Bolívar Departamento de Mecánica (*) Departamento de Conversión de Energía
oai:nur.nu.edu.kz:123456789/8502018-08-15T03:49:45Zcom_123456789_79com_123456789_67col_123456789_826
Experimental study of a gas-loquid cylindrical cyclone separator performance
Meléndez-Ramírez, Antonio J.
Reyes-Gutiérrez, Miguel A.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Gas-Liquid Cylindrical Cyclone separator
New data of the experimental performance of a Gas-Liquid Cylindrical Cyclone (GLCC) separator are presented. The data were collected using a 2 3/4” (0.07m) ID GLCC model working with an air-glycerin mixture. The inlet liquid flow rate, the inlet gas flow rate, the tangential liquid velocity inside the separator body and the gas carry under were measured for an operation regime without liquid carry over. The influence of the first
three parameters over the gas carry under was established. Results show the separator efficiency is mainly affected by the inlet gas flow rate for the explored conditions with slug flow at the GLCC entrance.
2015-12-04
2015-12-04
2004-11-13
Article
Antonio J. Meléndez-Ramírez, Miguel A. Reyes-Gutiérrez, Miguel A. Reyes-Gutiérrez; 2004, Experimental study of a gas-loquid cylindrical cyclone separator performance, http://nur.nu.edu.kz/handle/123456789/850
http://nur.nu.edu.kz/handle/123456789/850
en
Proceedings of IMECE2004 2004 ASME International Mechanical Engineering Congress November 13-19, 2004, Anaheim, California, USA
oai:nur.nu.edu.kz:123456789/8512018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
CFD modeling of porous media in the study of the flow at penstock intake of A 1:30 model of guri hydro-powerhouse
Arevalo, Angela
Montilla, Gonzalo
Rojas-Solorzano, L.
Reyes, Miguel
Marín, Juan
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
The transient free surface flow within a 1:30 model of the intake (penstock) to Power House II of Guri Hydro-Power Plant (Venezuela) is studied. The geometry of the model includes a reservoir of 4.31 meters upstream the dam. Geometric details and appropriate boundary conditions were reproduced mathematical and numerically using CFD (Computational Fluid Dynamics) techniques, running the commercial code CFXTM 4.4. The flow features nearby and within the penstock were captured. Special attention was paid to the evaluation of air entrainment that might eventually form due to the presence of free surface vortices. The computational domain included the anti-debris screen at the entrance of the penstock, considering it as a porous medium with equivalent permeability and porosity. Most of simulated cases corresponded to conditions in the prototype Guri´s free surface level of 240 a.s.l. (above sea level), with flow rate of 450 m3/seg. Air and water were considered incompressible fluids with and homogeneous interfacial transport model. Computed velocity profiles at different sections of the reservoir and pressure head along the penstock are compared with experiments. The numerical model captures the influence of the porous medium, used to simulate the anti-debris grill, onto the free-surface and pressure head within the penstock. In order to improve the predictive capabilities of the numerical model and to diminish the instabilities caused by the hydrostatic pressure condition at the entrance of the computational reservoir, preliminary results including a porous wall at the upstream boundary are presented. The porous wall, in fact, mimics the water-calming rock wall placed at the entrance of the experimental reservoir and proved to be a relevant element in improving the CFD predictions
2015-12-04
2015-12-04
2006
Article
Arevalo, Angela; Montilla, Gonzalo; Rojas-Solorzano, L.; Reyes, Miguel; Marín, Juan; 2006, CFD modeling of porous media in the study of the flow at penstock intake of A 1:30 model of guri hydro-powerhouse, http://nur.nu.edu.kz/handle/123456789/851
http://nur.nu.edu.kz/handle/123456789/851
en
CIMENICS MF-185-2006
oai:nur.nu.edu.kz:123456789/8522018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_825
Thermal Management of Lithium-ion Battery Packs
Adair, Desmond
Ismailov, Kairat
Bakenov, Zhumabay
thermal management
lithium-ion battery packs
cooling/heating methods
use of COMSOL Multiphysics-1
boundary conditions and settings
Temperature affects batteries in five major ways:
•operation of electrochemical system;
•efficiency and charge acceptance;
•power and energy efficiency;
•safety and reliability; and,
•life and life-cycle costs.
Li-ion batteries are extremely sensitive to low and high temperatures.
For battery packs it is important to regulate the pack to remain in the desired temperature range for optimum performance and life, and also to reduce uneven distribution of temperature throughout a packwhich would lead to reduced performance.
Importantly, the attainment of even temperature distributions through the battery pack eliminates potential hazards related to uncontrolled temperature build-up (‘thermal runaway’).
2015-12-04
2015-12-04
2014
Presentation
Adair Desmond., Ismailov Kairat., Bakenov Zhumabay., Thermal Management of Lithium-ion Battery Packs, 2014
http://nur.nu.edu.kz/handle/123456789/852
en
oai:nur.nu.edu.kz:123456789/8532018-08-15T03:49:45Zcom_123456789_79com_123456789_67col_123456789_826
Numerical simulation and experiments of the multiphase flow in a liquid-liquid cylindrical cyclone separator
Reyes, Miguel A.
Pacheco, Jorge E.
Marín, Juan C.
Rojas-Solorzano, L.
Rincón, José
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
multiphase flow
numerical simulation
oil-water
cyclone
separator
A Liquid-Liquid Cylindrical Cyclone separator (LLCC) is a device used in the petroleum industry to separate the oil-water mixture obtained from the well. The use of this device has not been widespread due to the lack of tools for predicting its separation capability. This paper presents a numerical and experimental study of the fluid dynamic performance of this type of cylindrical cyclone separators. The use of numerical simulations would reduce the time and cost necessary to obtain information for predicting the behavior of the equipment. The objective of this study is to determine if CFD (Computational Fluid Dynamics) techniques are able to reproduce the behavior of a LLCC separator. The CFD software examined was ANSYS-CFX 5.6TM and numerical simulations were carried out using the dispersed model with oil as the dispersed phase. The oil and water mixture entering the separator is divided due to centrifugal and buoyancy forces in an upper (oil rich) exit and a bottom (water rich) exit. The separation capability is determined as the maximum amount of water removed from the mixture with the minimum amount of oil content in the water rich exit. The experiments were conducted in a transparent LLCC separator that allows the visualization of the mixture and the measurement of the oil content. Experiments were conducted for three variables: mixture velocity and water content at the entrance, and the split ratio. The split ratio is defined as the bottom exit flow rate divided by the water flow rate at the entrance. The results showed that CFD tools are able to reproduce the oil content obtained from the experiments for all analyzed conditions. Additionally, the mixture distribution images from numerical and experimental data showed good agreement. This study confirms the capacity of CFD tools for the multiphase flow analysis of LLCC separators.
2015-12-04
2015-12-04
2006-07-17
Article
Miguel A Reyes, Jorge E Pacheco, Juan C Marín, Luis R Rojas, José Rincón, 2006, Numerical simulation and experiments of the multiphase flow in a liquid-liquid cylindrical cyclone separator, http://nur.nu.edu.kz/handle/123456789/853
http://nur.nu.edu.kz/handle/123456789/853
en
Proceedings of FEDSM2006 2006 ASME Joint U.S. - European Fluids Engineering Summer Meeting July 17-20, Miami, FL
oai:nur.nu.edu.kz:123456789/8542018-08-15T03:49:45Zcom_123456789_79com_123456789_67col_123456789_821
LiMnPO4 olivine as a cathode for lithium batteries
Bakenov, Zhumabay
Taniguchi, Izumi
spray pyrolysis
LiMnPO4
lithium secondary batteries
cathode materials
The olivine structured mixed lithium-transition metal phosphates LiMPO4 (M = Fe, Mn, Co) have attracted
tremendous attention of many research teams worldwide as a promising cathode materials for lithium batteries. Among
them, lithium manganese phosphate LiMnPO4 is the most promising considering its high theoretical capacity and
operating voltage, low cost and environmental safety. Various techniques were applied to prepare this perspective cathode
for lithium batteries. The solution based synthetic routes such as spray pyrolysis, precipitation, sol-gel, hydrothermal and
polyol synthesis allow preparing nanostructured powders of LiMnPO4 with enhanced electrochemical properties, which is
mostly attributed to the higher chemical homogeneity and narrow particle size distribution of the material. Up-to-date, the
LiMnPO4/C composites prepared by the spray pyrolysis route have the best electrochemical performance among the
reported in the literature.
2015-12-04
2015-12-04
2011-12-02
Article
Bakenov Zhumabay., Taniguchi Izumi., 2011, LiMnPO4 olivine as a cathode for lithium batteries, DOI: 10.2174/1874088X01105010222
http://nur.nu.edu.kz/handle/123456789/854
en
The Open Materials Science Journal, http://www.researchgate.net/publication/260969132
oai:nur.nu.edu.kz:123456789/8552018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Two-dimensional numerical simulation of saltating particles using granular kinetic theory
Marval, Juan P.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
saltation layer
Granular Kinetic Theory
CFD
Most granular flows at environmental conditions are unsteady and exhibit a complex physical behavior. Dune formation and migration in the desert are controlled not only by the flow of saltating particles over the sand bed, but also by turbulent atmospheric airflow. In fact, sediments are transported by the atmospheric airflow within a thin layer only a few centimeters above the sandy surface. These jumping particles reach a maximum sediment mass flux level at a certain delay time (known as the “saturation time”) after the initial movement by sliding and rolling begins. Unlike sediment transport in water where the particles are lifted by the turbulent suspension, the saltating particles are kept alive in the layer mainly due to particle-particle and particle-bed collisions. In order to model this Aeolian transport of sand, Jenkins and Pasini [1] proposed a two-fluid model (one-dimensional and steady state) using Granular Kinetic Theory (GKT) to describe the solid-phase stress. The present work extends the original idea of Jenkins and Pasini [1] by using a more robust model of GKT for the kinetic/collisional contributions to the solid-phase stress tensor, together with a friction model activated for sustained contacts between particles. In addition, a standard k-ε turbulence model for the air and a drag model for the interaction between the phases are employed. A rectangular 2D geometry was chosen with a logarithmic profile for the inlet air velocity, along with an initial amount of sand at rest in the lower part of the simulation domain, resembling the particle saltating flow commonly seen in the vertical middle plane within saltation wind tunnels. This model is validated with experimental data from Liu and Dong [2] and the results given by Pasini and Jenkins [1]. A good estimation for the particle erosion and mass flux in the saltation layer is predicted, even though the profiles of mass flux and concentration within the transport layer are very thin and lower
2015-12-04
2015-12-04
2007-06-30
Article
Juan P. Marval, Luis R. Rojas-Solórzano; 2007; Two-dimensional numerical simulation of saltating particles using granular kinetic theory, http://nur.nu.edu.kz/handle/123456789/855
http://nur.nu.edu.kz/handle/123456789/855
en
Proceedings of FEDSM2007 2007 ASME/JSME Fluids Engineering Division Summer Meeting July 30-August 2, 2007, San Diego, California, USA
oai:nur.nu.edu.kz:123456789/8562018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Selection and validation of a turbulence model for the numerical simulation of the flow at hemodialysis cannulas
Salazar, Félix A.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Computational Fluid Dynamics
Turbulence Model
Cannula
Blood
In recent years, CFD has become an increasingly used tool in the design of blood-based devices. Particularly, the estimation of red blood cell damage (hemolysis) becomes an important challenge to CFD scientists since the blood is a complex fluid present in turbulent regime in most pumping devices. Moreover, previous CFD studies on blood hemolysis lack of reliable relationships between hydraulic results and hematological responses. The objective of this work is to foresee a methodology for performing realistic CFD simulations that lead to reliable hydraulic and hematological correspondence. Cannulae geometries were studied to numerically assess a relatively simple flow with documented hematological data. For the turbulence modeling, a direct numerical simulation (DNS) for a coaxial jet array was used as a benchmark for the selection of an appropriate turbulence model, since the Cannulae approximates the coaxial jet features. Velocity and stress time-averaged profiles were compared between DNS results and the turbulence models. These results, pointed to the Shear Stress Transport with Gamma Theta correlation for transition model as the optimum turbulence model in that geometry. Accurate and reliable hydrodynamic CFD results were obtained for the Cannulae as a previous step to further hematological calculations with a minimum degree of uncertainty
2015-12-04
2015-12-04
2007-09-24
Article
Félix A. Salazar, Luis R. Rojas-Solórzano; 2007; Selection and validation of a turbulence model for the numerical simulation of the flow at hemodialysis cannulas, http://nur.nu.edu.kz/handle/123456789/856
http://nur.nu.edu.kz/handle/123456789/856
en
III INTERNATIONAL CONGRESS ON COMPUTATIONAL BIOENGINEERING M. Cerrolaza, H. Rodrigues, M. Doublaré, J. Ambrosio, M. Viceconti (Eds.) Isla de Margarita, Venezuela, September 24 to 26, 2007
oai:nur.nu.edu.kz:123456789/8572018-08-15T03:49:45Zcom_123456789_79com_123456789_67col_123456789_826
CFD modeling of slurry flows in horizontal pipes
Hernández, Franz H.
Blanco, Armando J.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
CFD
Computational Fluid Dynamics
Liquid-solid two-phase flows are found in numerous operations in the chemical, petroleum, pharmaceutical and many other industries. In numerous cases, the mixture or slurry that flows is composed by a suspension of solid particles (dispersed phase) transported by a liquid (continuum phase). However, the large number and range of variables encountered in slurry flows, in the case of pipelines, cause the flow behavior of these slurry systems to vary over a wide range of conditions, and consequently, different approaches have been used to describe the behavior of different flow regimes. Therefore, there are numerous studies of particular cases that cover limited ranges of conditions. In consequence, the experimental approach is necessarily limited by geometric and physical scale factors. For these reasons, Computational Fluid Dynamics, CFD, constitutes an ideal technique for predicting the general flow behavior of these systems. CFD models in this area can be divided in two different classes: Eulerian-Eulerian and Lagrangian-Eulerian models. Differences between these models are related to the way the solid phase flow is represented. Lagrangian-Eulerian models calculate the path and motion of each particle, while Eulerian-Eulerian models treat the particle phase as a continuum and average out motion on the scale of individual particles.
This work focuses on the Eulerian-Eulerian approach for modeling the flow of a mixture of sand particles and water in a horizontal pipe. Homogeneous and heterogeneous flow regimes are considered. The k-ε model was used for modeling turbulent effects. Additionally, closure of solid-phase momentum equations requires a description for the solid-phase stress. Constitutive relations for the solid-phase stress considering the inelastic nature of particle collisions based on the Gas Kinetic Theory concepts have been used.
Governing equations are solved numerically using the control volume-based finite element method. An unstructured non-uniform grid was chosen to discretize the entire computational domain. A second-order scheme in space and time was used. Numerical solutions in fully developed turbulent flow were found.
Results show that flow predictions are very sensitive to the restitution coefficient and pseudo-viscosity of the solid phase. The mean pressure gradients from numerical solutions were compared with results obtained using the correlations of Einstein, Thomas and Krieger for homogeneous cases and with experimental data found in the open literature for heterogeneous cases. The solutions were found to be in good agreement with both correlations and experimental data. In addition, these numerical results were closer to experimental data than results obtained using other numerical models.
2015-12-04
2015-12-04
2008-08-17
Article
Franz H. Hernández, Armando J. Blanco, Luis Rojas-Solórzano; 2008; CFD modeling of slurry flows in horizontal pipes, http://nur.nu.edu.kz/handle/123456789/857
http://nur.nu.edu.kz/handle/123456789/857
en
Proceedings of FEDSM2008 8th Symposium on Applications in Computational Fluid Dynamics August 17-20, Jacksonville, FL
oai:nur.nu.edu.kz:123456789/8592018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
Advanced Numerical Solver for Dam-Break Flow Application
Hui Pu, Jaan
Bakenov, Zhumabay
Adair, Desmond
advanced numerical solver
dam-break flow
In this paper, a HLL (Harten Lax van Leer) approximate Riemann solver with MUSCL scheme
(Monotonic Upwind Schemes for Conservative Laws) is implemented in the presented FV (Finite
Volume) model. The presented model is used to simulate different dam-break flow events to verify its
capability. Four test cases are presented in this paper. In the first test case, a 1-Dimensional (1D) dambreak
flow is simulated over a rectangular channel with different slope limiters of the FV model (namely
Godunov, Superbee, Minmod, van Leer, and van Albada). The second test case consists of a simulation of
shallow water discontinuous dam-break flow over a dry-downstream bed channel. The third test simulates
the shallow water dam-break flow with the existence of bed slope and bed shear stress. Finally, in the last
test, the HLL-MUSCL model used in this paper and some other solver models used in literature are
compared against the referred exact solution in dam-break flow application. The presented HLL-MUSCL
scheme is found to give the best agreement to the exact solution.
2015-12-04
2015-12-04
2012-01
Article
Hui Pu Jaan., Bakenov Zhumabay., Adair Desmond., 2012, Advanced Numerical Solver for Dam-Break Flow Application
http://nur.nu.edu.kz/handle/123456789/859
en
Eurasian chemico-technological journal., http://www.researchgate.net/publication/283813681
oai:nur.nu.edu.kz:123456789/8582018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Numerical study of turbulence models in the computation of blood flow in cannulas
Salazar, Felix A.
Rojas-Solorzano, L.
Antaki, James F.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
CFD
In recent years, CFD has become an increasingly used tool in the design of blood-based devices. However, the estimation of red blood cells damage (hemolysis) remains a very important challenge due to the complex rheology of blood and the turbulence present in most pumping devices. The objective of this study was to identify an appropriate turbulence model suitable for predicting hemolysis in Hemodialysis cannula. Several modern turbulence models were evaluated in comparison to Direct Numerical Simulation (DNS), which was used as the gold standard. The fluid dynamics in the cannula was modeled as a coaxial jet in which Reynolds’ number approached 2800. Based on comparison of velocity and stress time-averaged profiles, the Shear Stress Transport (SST) model with Gamma-Theta transition was identified as an optimal compromise between accuracy and computational cost.
2015-12-04
2015-12-04
2008-08-10
Article
Felix A. Salazar, Luis R. Rojas-Solórzano, James F. Antaki; 2008; Numerical study of turbulence models in the computation of blood flow in cannulas, http://nur.nu.edu.kz/handle/123456789/858
http://nur.nu.edu.kz/handle/123456789/858
en
Proceedings of FEDSM2008 2008 ASME Fluids Engineering Conference August 10-14, 2008, Jacksonville, FL, USA
oai:nur.nu.edu.kz:123456789/8602018-08-15T03:49:45Zcom_123456789_79com_123456789_67col_123456789_821
Ternary sulfur/polyacrylonitrile/Mg0.6Ni0.4O composite cathodes for high performance lithium/sulfur batteries
Zhang, Yongguang
Zhao, Yan
Yermukhambetova, Assiya
Bakenov, Zhumabay
Chen, P.
ternary sulfur
polyacrylonitrile
composite cathodes
high performance lithium
sulfur batteries
Nanostructured magnesium nickel oxide (Mg0.6Ni0.4O) was synthesized by a self-propagating high
temperature synthesis method followed by heat treatment. The particles of the resulting oxide were
used as additives to prepare the sulfur/polyacrylonitrile/Mg0.6Ni0.4O (S/PAN/Mg0.6Ni0.4O) composite via
wet ballmilling. The SEM observation revealed that the composite morphology was drastically changed
by the addition of Mg0.6Ni0.4O, from smooth bulky particles of S/PAN to rough nanostructured
agglomerates with two times the increase in the specific surface area, favouring the reactivity of the
composite, and a homogeneous component distribution. Cyclic voltammetry, discharge–charge tests and
ac impedance spectroscopy have shown improved conductivity and electrochemical properties of the
composite by the addition of Mg0.6Ni0.4O, leading to high sulfur utilization and interfacial stabilization
in a Li/S cell upon discharge–charge cycling. The cell demonstrated enhanced reversibility, resulting in a
discharge capacity of about 1223 mA h g 1 at the second cycle and retained about 100% of this value
over 100 cycles. Furthermore, the S/PAN/Mg0.6Ni0.4O composite cathode exhibited a good rate
capability with discharge capacities of 887, 710 and 445 mA h g 1 at 0.5, 0.7 and 1 C, respectively.
2015-12-04
2015-12-04
2013-01
Article
Zhang Yongguang., Zhao Yan., Yermukhambetova Assiya., Bakenov Zhumabay., Chen P., 2013, Ternary sulfur/polyacrylonitrile/Mg0.6Ni0.4O composite cathodes for high performance lithium/sulfur batteries, DOI: 10.1039/c2ta00105e
http://nur.nu.edu.kz/handle/123456789/860
en
Journal of materials chemistry., http://www.researchgate.net/publication/235654118
oai:nur.nu.edu.kz:123456789/8612018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Numerical study of smoke propagation in a simulated fire in a wagon within a subway tunnel
Vittori, Felipe
Rojas-Solorzano, L.
Blanco, Armando J.
Urbina, Rafael
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
CFD
This work deals with the numerical (CFD) analysis of the smoke propagation during fires within closed environments. It is evaluated the capacity of the emergency ventilation system in controlling the smoke propagation and minimizing the deadly impact of an eventual fire in a wagon within the Metro de Caracas subway tunnel on the passengers safety. For the study, it was chosen the tunnel section between Teatros and Nuevo Circo subway stations, which consists of two parallel independent twin tunnels, connected through a transverse passage. The tunnels are provided by a longitudinal ventilation system, integrated by a set of reversible fans located at both ends of the tunnels.
Three stages were considered in the study: (a) Model set up; (b) Mesh sensitivity analysis; (c) Validation of the physical-numerical parameters to be used in the numerical model; and (d) Simulation of fire scenarios in Metro de Caracas subway stations. Stages (b)-(c), aimed to testing and calibrating the CFD tool (ANSYS-CFX10TM), focused on reproducing experimental data from Vauquelin and Mégret [1], who studied the smoke propagation in a fire within a 1:20 scale road tunnel. Stage (d) critical scenarios were established via a preliminary discussion with safety experts from Metro de Caracas, in order to reduce the computer memory and the number of simulations to be performed. The analyses assessed the reliability of escape routes and alternative paths for the evacuation of passengers. Additionally, the smoke front movement was particularly computed, as a function of time, in order to determine the possible presence of the ¨backlayering¨ phenomenon [5]. Results demonstrate the strengths and weaknesses of the current ventilation system in the event of a fire in the subway tunnel, and suggest new strategies to address this potentially lethal event to minimize the risks for passengers
2015-12-04
2015-12-04
2008-08-10
Article
Felipe Vittori, Luis Rojas-Solórzano, Armando J. Blanco, Rafael Urbina; 2008; Numerical study of smoke propagation in a simulated fire in a wagon within a subway tunnel, http://nur.nu.edu.kz/handle/123456789/861
http://nur.nu.edu.kz/handle/123456789/861
en
Proceedings of FEDSM2008 2008 ASME Fluids Engineering Conference August 10-14, 2008 Jacksonville, Florida USA
oai:nur.nu.edu.kz:123456789/8622018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Numerical simulation of draft tube flow in off-design conditions
Arzola, Fidel
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
draft tube
numerical simulation
vortex rope
pressure fluctuation
Draft tube flow fields are simulated with 3D unsteady Reynolds averaged Navier-Stokes equations.The purpose of this study is the modeling, simulation and characterization of a complex threedimensional unsteady flow inside a Francis turbine draft tube for two specific off-design conditions: A) Part load (0.88Q), frequently characterized by the occurrence of an unsteady rotating vortex rope linked to strong pressure fluctuations and, B) High load (1.21Q), where softer pressure surges taking place because the cavity volume at this condition has an axisymmetric shape. This work takes place after overhaul works on the actual turbine, which include new runner and wicket gates and modifications on stay vanes and other passageways; where power output, efficiency and stable operating range were increased. The computational domain consists of the draft tube alone. A relative poor mesh (430k nodes) and the k-ε turbulence model are implemented in order to get a quick, but clear explanation to understand how the flow in the existing draft tube responds in front of a new velocity distribution at runner outlet for off-design conditions. Numerical results are qualitative and quantitatively analyzed and compared with experimental data from model and prototype. The unsteady and complex nature of the flow field distribution inside the draft tube for both conditions is visualized
2015-12-04
2015-12-04
2008-10-27
Article
Fidel Arzola, Luis Rojas-Solórzano; 2008; Numerical simulation of draft tube flow in off-design conditions, http://nur.nu.edu.kz/handle/123456789/862
http://nur.nu.edu.kz/handle/123456789/862
en
IAHR 24th Symposium on Hydraulic Machinery and Systems OCTOBER 27-31, FOZ DO IGUASSU
oai:nur.nu.edu.kz:123456789/8632018-08-15T03:49:45Zcom_123456789_79com_123456789_67col_123456789_826
CFD software applications for transcritical free surface flow
Pineda, Saira F.
Blanco, Armando J.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Flows in rivers, floodplains and coastal zones are very complex due to uneven bottom topography and irregular boundaries of the flow domain. In particular, when the flow shows strong gradients in water depth and velocity it is very difficult to predict, with accuracy, flow characteristics such as water profiles in all points of the domain. Traditional approaches solve shallow-water flow equations, known as Saint-Venant equations, when one or two dimension solutions can be adequate for obtaining most of the important flow characteristics. However, complex situations can require solving Navier-Stokes equations. In these cases, a two-phase flow problem must be solved and, as water profiles are not known in advance, only a numerical approach can be used to obtain approximate solutions. In addition, flow can be subcritical, supercritical or in a mixed-flow regime. These flow characteristics and complex geometries can make the use of in-house developed software difficult. The arrival of high performance computers and commercial software packages offers new possibilities in the field of numerical hydraulics. However, commercial software packages should be tested on some specific cases; so that these can be used with confidence. In this paper we solve, several cases of free surface flow that consider subcritical, supercritical, critical, oscillatory depth profiles and hydraulic jumps using a commercial package, CFX™. Most of these cases were proposed as benchmark solutions by MacDonald et al. (1997) for non-prismatic cross section, non-uniform bed slope and transition between subcritical and supercritical flow. Hydraulic jump cases consist of experimental data of hydraulics jumps obtained by Gharangik & Chaudhry (1991) for incident flow with Froude numbers of 2.3 and 4.23. In all simulated cases flow was described using a homogeneous model for each phase of the flow. Turbulence was modeled by using the well-known k-ε model. In addition, sensitivity to turbulence level in the entrance of flow domain was done to assure independence of results with this variable. Experimental facilities were properly represented in order to assure exact correspondence between boundary conditions of the model and the actual facility. Results obtained with CFX™ show excellent agreement with analytical solutions, for subcritical, supercritical, transitional and hydraulic jump cases. Special care with grid selection and entrance boundary condition is crucial to simulate with accuracy these types of flows. In particular, when a proper structured mesh is used, quality results are highly improved. Finally, results show to be insensitive to entrance turbulence conditions
2015-12-04
2015-12-04
2009-08-02
Article
Saira F. Pineda, Armando J. Blanco, Luis Rojas-Solórzano; 2009, CFD software applications for transcritical free surface flow, http://nur.nu.edu.kz/handle/123456789/863
http://nur.nu.edu.kz/handle/123456789/863
en
Proceedings of FEDSM2009 ASME 2009 Fluids Engineering Division Summer Meeting August 2-5, 2009, Vail, Colorado USA
oai:nur.nu.edu.kz:123456789/8642018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Modeling and simulation of a rollerball microfluidic device
Rojas-Solorzano, L.
Shelley L., Anna
Bradeddine, Bourtal
Amon, Cristina H.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
The fluid delivery process through a rollerball device is investigated by means of physical modeling and numerical simulations. The microfluidic device is intended to deliver liquid above a substrate interacting with the surrounding air. While the fluid is delivered, air entrainment occurs through the capillary gap, creating a two-phase liquid-gas mixture whose composition and properties affect significantly the quality of the continuous fluid deposition. For the numerical solution of the 2D two-phase flow governing equations, the finite volumebased finite element method is used with 2nd order time-space schemes for the fully coupled system of equations. The quality of the liquid micro-volume delivery proves to be largely affected by both the speed of the roller and fluid properties. It
is found that only under very low speed and some fluid properties, it is possible to guarantee a gas free liquid deposition. Envisioning the potential use of this convenient and
popular device in the deployment of microfluid layers or substances at very small quantities with controlled quality, it is apparent the need for handling and channeling out the air entrainment without perturbing the liquid quality
2015-12-04
2015-12-04
2009-06-22
Article
Luis R. Rojas-Solórzano, Bourtal Bradeddine, Shelley L. Anna, Cristina H. Amon; 2009; Modeling and simulation of a rollerball microfluidic device, http://nur.nu.edu.kz/handle/123456789/864
http://nur.nu.edu.kz/handle/123456789/864
en
Proceedings of the 7th International Conference on Nanochannels, Microchannels and Minichannels ICNMM2009 June 22-24, 2009, Pohang, South Korea
oai:nur.nu.edu.kz:123456789/8652018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
CFD modeling of a road tunnel with multiple sources of Co. case of study: boqueron-I tunnel
Urbina, Rafael J.
Rojas-Solorzano, L.
Blanco, Armando J.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
This work aims to the modeling of CO transport in one section considered critical of the
Boqueron I tunnel, located on the outskirts of Caracas, the capital city of Venezuela, with a
scenario where vehicles are stopped by an interruption of traffic. This scenario considers a relationship between the number of large-sized vehicles (buses or trucks) and small-sized vehicles (passenger cars) reported by transit statistics and also, it considers the semi-transverse ventilation system in the tunnel. It is explored the influence of the ventilation on the flow patterns and its relationship to the regions with the highest CO concentration. The finite-volume based finite element method is used for the discretization of the computational domain and the integration of the governing equations. The transient 3D-incompressible Navier-Stokes, energy, mass and species conservation equations, along with the k-e turbulence equations, were discretized, using higher-order numerical schemes in space. The numerical simulation is performed using a fully implicit coupled treatment of the set of resulting discrete transport equations
2015-12-04
2015-12-04
2009-04
Article
Rafael J. Urbina, Luis Rojas-Solórzano, Armando J. Blanco; 2009; CFD modeling of a road tunnel with multiple sources of Co. case of study: boqueron-I tunnel, http://nur.nu.edu.kz/handle/123456789/865
http://nur.nu.edu.kz/handle/123456789/865
en
Second International Tunnel Safety Forum, Lyon, April 2009
oai:nur.nu.edu.kz:123456789/8662018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Pre-feasibility study for PV electrfication of off-grid rural communities
Akiki, Georgio
Hinrichs, Federico
Zuylen, Roderick A.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Photovoltaic system
Rural electrification
Life cycle cost
RETscreenTM
A pre-feasibility study has been undertaken for the electrification of the rural off-grid village of Hurhudedanda, Nepal. PV solar was deemed most suitable after an assessment of local wind, micro-hydro, solar and biogas potential. To determine the most cost-effective PV configuration, different scenarios were simulated using RETscreenTM. Decentralized Solar Home Systems (SHS) resulted in lower life cycle costs than centralized PV generation (1.25 $/kWh and 1.46 $/kWh respectively) and might be the best alternative for a first stage of electrification. A final study has been undertaken to assess the proposed system’s ability to deal with a forecasted load increase
2015-12-04
2015-12-04
2010-11-05
Article
Georgio Akiki, Federico Hinrichs, Roderick A. van Zuylen, Luis Rojas-Solórzano; 2010; Pre-feasibility study for PV electrfication of off-grid rural communities,http://nur.nu.edu.kz/handle/123456789/866
http://nur.nu.edu.kz/handle/123456789/866
en
International Renewable Energy Congress November 5-7, 2010 – Sousse, Tunisia
oai:nur.nu.edu.kz:123456789/8672018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Conceptual and basic design of a stirling engine prototype for electrical power generation using solar energy
Roldan, Constantino
Pieretti, Pedro
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
The research consisted in a conceptual and basic design of a prototype Stirling engine with the purpose of taking advantage of the solar radiation to produce electric energy. The
work began with a bibliography review covering aspects as history, basic functioning, design configurations, applications and analysis methods, just to continue with the conceptual design, where the prototype specifications were determined. Finally, a basic dimensioning of the important components as heat exchangers (heater, cooler, and regenerator), piston, displacer and solar collector was elaborated. The principal conclusions were that the different analysis methods had dissimilitude among their results; in this sense, a construction of the prototype is necessary for the understanding of the complex phenomena occurring inside the engine
2015-12-04
2015-12-04
2010
Article
Constantino Roldan, Pedro Pieretti, Luis Rojas-Solórzano; 2010; Conceptual and basic design of a stirling engine prototype for electrical power generation using solar energy, http://nur.nu.edu.kz/handle/123456789/867
http://nur.nu.edu.kz/handle/123456789/867
en
oai:nur.nu.edu.kz:123456789/8682018-08-15T03:50:25Zcom_123456789_79com_123456789_67col_123456789_826
Simulation of the Velocity field in compound channel flow using different closure models
Filonovich, M.
Azevedo, R.
Rojas-Solorzano, L.
Leal, J. B.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
In this study a comparison of three turbulence closure models (two isotropic and one anisotropic) with experimental data is performed. The interaction between the main channel (MC) flow and the floodplain (FP) generates a complex flow structure. A shallow mixing layer develops between the MC flow and the slower FP flow generating a high horizontal shear layer, streamwise and vertical vortices, momentum transfer and other phenomena, related to velocity retardation and acceleration. This phenomenon dissipates part of the kinetic energy and contributes to the reduction of the velocity differences between the MC and the FP. The large scale vortices that are generated in the shear layer are anisotropic, provoking the formation of secondary flow cells that influence the primary velocity distribution. These threedimensional turbulent structures can be reasonable well reproduced by a simple anisotropic model (Algebraic Stress Model). The isotropic models are capable of simulating the boundary layer, especially the model base in k-ω equations,
but cannot simulate the shear layer that develops at the interface
2015-12-04
2015-12-04
2010
Article
M. Filonovich, R. Azevedo, L. R. Rojas-Solorzano, J. B. Leal; 2010; Simulation of the Velocity field in compound channel flow using different closure models, http://nur.nu.edu.kz/handle/123456789/868
http://nur.nu.edu.kz/handle/123456789/868
en
oai:nur.nu.edu.kz:123456789/8692018-08-15T03:49:45Zcom_123456789_79com_123456789_67col_123456789_826
Pre-feasibility study of a biogas plant for peyrelevade community
Koh, Pei Ling
Pomarico, Victor
Tadepalli, Venkata Phani
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Grass Silage
Biogas
Boiler
CHP
RETScreen
This work presents a technical and financial pre-feasibility assessment for heat generation from biogas for a retirement home in the community of Peyrelevade, France. The heat demand of the retirement home currently relies on fuel oil boiler and electric heaters. The biogas is to be produced mainly from grass silage. As result of the feedstock abundance in the community, electricity can be also generated in an 80kWe CHP unit operating in full power capacity. The electricity produced can be then sold to the national electricity utility in France. The financial analysis was carried out using RETScreenTM. An efficiency of 62.9% is achievable in this CHP (Combined heat and power) biogas plant, with a total life cycle saving/income of 0.05€ for each MJ of heat supplied to the retirement home. A company set-up has also been proposed for the development of a community based company
2015-12-04
2015-12-04
2010-11-05
Article
Pei Ling Koh, Victor Pomarico, Venkata Phani Tadepalli, Luis Rojas-Solórzano; 2010; Pre-feasibility study of a biogas plant for peyrelevade community, http://nur.nu.edu.kz/handle/123456789/869
http://nur.nu.edu.kz/handle/123456789/869
en
International Renewable Energy Congress November 5-7, 2010 – Sousse, Tunisia
oai:nur.nu.edu.kz:123456789/8702018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Verification and validation of computational fluid dynamics simulations of compound channel
Filonovich, M. S.
Azevedo, R.
Rojas-Solorzano, L.
Leal, J. B.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
CFD
GCI
EARSM
compound channel
verification
validation
In this study the verification and validation of a 2nd order turbulence closure model is performed for an experimental compound channel flow, where the velocity field was measured by a Laser Doppler Velocimeter. Detailed Explicit Algebraic Reynolds Stress Model (EARSM) simulation is reported. The Grid Convergence Index (GCI) approach proposed by Roache (1998) was adopted to evaluate the uncertainty associated to grid resolution. The velocity components, the turbulent kinetic energy (TKE) and the dissipation rate were used as variables of interest. The GCI results present low values for the streamwise velocity, TKE and dissipation rate, but higher values in what concerns vertical and spanwise velocities. This indicates that the mean primary flow has converged but the secondary flow field still depends on grid resolution. Based on GCI values distribution, the mesh was locally refined. Comparison of numerical and experimental results shows good agreement
2015-12-04
2015-12-04
2010
Article
M. S. Filonovich, R. Azevedo, L. R. Rojas-Solorzano, J. B. Leal; 2010; Verification and validation of computational fluid dynamics simulations of compound channel, http://nur.nu.edu.kz/handle/123456789/870
http://nur.nu.edu.kz/handle/123456789/870
en
oai:nur.nu.edu.kz:123456789/8712018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Comparative study of rans turbulence models for impinging jet simulations
F., Vittori
Rojas-Solorzano, L.
Pavageau, M.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Impinging plane jets are flow configurations with applications in many fields. The ability of several turbulence models to simulate this kind of flow was assessed. The numerical results were compared with the data of Cooper et al. (1993) for Re=7.0 104 and a jet nozzle aspect ratio H/D=6, and Re=2.3 104 and H/D=2. The SST, RSM-ε and RSM-BSL turbulence models were chosen because of their capability to predict flows with high streamline curvature and their expected good accuracy on near wall flow. The results show that the SST and RSM- ε perform better than the RSM-BSL in the prediction of the mean velocity profiles in the wall-jet and impact zone. The profiles of turbulent energy were particularly difficult to reproduce. All the turbulence models considered here exhibit a similar behavior with respect to the profiles of turbulent energy. The paper shows again the complexity of turbulent impinging jets and the relevant open challenges in CFD
2015-12-04
2015-12-04
2011
Article
Vittori F., Rojas-Solórzano L., Pavageau M.; 2011; Comparative study of rans turbulence models for impinging jet simulations, http://nur.nu.edu.kz/handle/123456789/871
http://nur.nu.edu.kz/handle/123456789/871
en
Memorias del Congreso ASME USB 2011: IX CONGRESO ANUAL DE INGENIERÍA ASME USB 2011 03, 04 Y 05 de junio, 2011, Caracas - Venezuela
oai:nur.nu.edu.kz:123456789/8722018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
CFD Simulation of Air-water in a Spouted Bed
Riera-Ortiz, Jaime
Zeppieri, Suzana
Rojas-Solorzano, L.
Derjani, Sylvana
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Computational fluid dynamics (CFD) is employed to simulate the air-water system in a spouted column with a draft tube. Numerical results of Reynolds-averaged Navier-Stokes (RANS) equations using the k-s and k-w two-equation turbulence models are compared with Pironti at al. (1995) experimental data. CFD predictions of the k-s and k-w turbulence models are in good agreement with the reported experimental data. The interfacial momentum transfer in modeling air-water system in the spouted bed indicated the importance of using turbulent dispersion force besides the most often used drag and lift forces to better predict flow behavior and air hold-up. Ishii-Zuber liquid-gas drag model with the lift and turbulent dispersion forces yields very good results; it correctly determines a hold up within 1% when used along with the k-s turbulence model, while it under-predicts the hold-up by 4.08% when used with the k-co model.
2015-12-04
2015-12-04
2011
Article
Jaime Riera-Ortiz, Suzana Zeppieri, Luis Rojas-Solorzano, Sylvana Derjani; 2011; CFD Simulation of Air-water in a Spouted Bed
http://nur.nu.edu.kz/handle/123456789/872
en
oai:nur.nu.edu.kz:123456789/8732018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_825
Lithium sulfur battery: current status and future prospects
Hara, Toru
Konarov, Aishuak
Mentbayeva, Almagul
Kurmanbayeva, Indira
Bakenov, Zhumabay
lithium sulfur battery
future prospects
This publication has been made within the Sub-project #157-2013 which is funded under the Technology Commercialization Project, supported by the World Bank and the Government of the Republic of Kazakhstan.
2015-12-04
2015-12-04
2013
Presentation
Hara Toru., Konarov Aishuak., Mentbayeva Almagul., Kurmanbayeva Indira., Bakenov Zhumabay., Lithium sulfur battery: current status and future prospects
http://nur.nu.edu.kz/handle/123456789/873
en
oai:nur.nu.edu.kz:123456789/8742018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_825
Analytical modelling of planar potential and current distributions in electrodes of lithium-Ion batteries
Adair, D.
Hara, Toru
Massalin, Y.
Ismailov, K.
Bakenov, Zhumabay
analytical modelling
electrodes of lithium-Ion batteries
Mathematical modelling can play an important role in the design of a lithium-ion cell
in that many design iterations can be performed at relatively little cost.
• Electrochemical models are useful for cell design and optimization but can be
typically high-order and complex and hence computationally expensive, and, are
therefore not suitable for real-time applications.
• Much reduced order electrochemical models for lithium-ion cells have been
developed, with these type of models more suitable for use with real-time on-board
electronic control units.
• However, a difficulty with these methods is that the current-voltage behavior for
different operating conditions cannot be predicted.
2015-12-04
2015-12-04
2015-11-11
Presentation
Adair D., Hara T., Massalin Y., Ismailov K., Bakenov Z., 2015, Analytical modelling of planar potential and current distributions in electrodes of lithium-Ion batteries
http://nur.nu.edu.kz/handle/123456789/874
en
Analytical modelling of planar potential and current distributions in electrodes of lithium-Ion batteries
oai:nur.nu.edu.kz:123456789/8752018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_825
Three-dimensional Zn/LiFePO4 aqueous hybrid-ion battery for renewable energy integration into electrical grids.
Hara, Toru
Antonov, Anton
Umirov, Nurzhan
Bakenov, Zhumabay
three-dimensional Zn/LiFePO4
aqueous hybrid-ion battery
renewable energy integration
electrical grids
Renewable energy integration into electrical grids is crucial for energy security, leading to the highly secured communication network, traffic control, industrial activities, etc.
Renewable energies are intermittent and cannot be easily directly integrated to electric grids without using batteries.
These batteries must be safe and inexpensive from the viewpoint of life-cycle cost.
Aqueous batteries are non-flammable that can be a great merit compared with traditional lithium-ion batteries that use flammable organic electrolyte solutions.
2015-12-04
2015-12-04
2015-11-11
Presentation
Hara Toru., Antonov Anton., Umirov Nurzhan., Bakenov Zhumabay., 2015, Three-dimensional Zn/LiFePO4 aqueous hybrid-ion battery for renewable energy integration into electrical grids
http://nur.nu.edu.kz/handle/123456789/875
en
oai:nur.nu.edu.kz:123456789/8762018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Biogas home-production assessment using a selective sample of organic vegetable waste. A preliminary study
Durán-García, Martín
Ramírez, Yrina
Bravo, Ricardo
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Anaerobic Digestion
Biodigesters
Biogas
Biomethane Potential Measurement
Substrate
Biogas generation plants using organic waste are a daily reality that can be observed in different areas of waste disposal that exist in many cities of the world. In fact, the generation of biogas through anaerobic bio-digestion of urban wastes has a high impact in terms of energy use and reduced environmental liabilities. The present study focuses on the assessment of biogas production for domestic consumption; several biodigesters
were tested in order to evaluate the biogas production under
standard pressure and temperature. The test estimates volume
of biogas being produced, substrate pH and substrate concentration,
using different types of catalysts. A test bed was designed
for testing three digesters (A, B and C) within recycled
bottles of polyethylene terephthalate (PET), whose maximum
volume is ~0.6 liters. A 60g organic substrate compound was
placed in each bottle. The organic compound consisted of peeling
residues of potatoes, cabbage and carrots. Experimental
characterization of the mixture allowed to observe the production
of biogas for domestic use, system temperature, pH levels
achieved, mass and substrate concentration, as well as concentration
and volume of the catalyst. Further studies, with a
larger sample and monitoring the container pressure are recommended
in order to establish a more precise relation among
the whole set of experimental parameters.
2015-12-07
2015-12-07
2012-02
Article
Martín Durán-García, Yrina Ramírez, Ricardo Bravo, Luis Rojas-Solórzano; 2012; Biogas home-production assessment using a selective sample of organic vegetable waste. A preliminary study; http://nur.nu.edu.kz/handle/123456789/876
http://nur.nu.edu.kz/handle/123456789/876
en
Red de Revistas Científicas de América Latina, el Caribe, España y Portugal Sistema de Información Científica
oai:nur.nu.edu.kz:123456789/8772018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
Evaluation of Interphase Drag Models for the Determination of Gas Hold-Up of an Air-Water System in a Spouted Bed using CFD
Riera Ortiz, Jaime. A.
Zeppieri, Susana
Rojas-Solorzano, L.
Derjani-Bayeh, Sylvana
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Interfacial drag models
Holdup
Spouted bed column
CFD
k-ε
Abstract: The hydrodynamics of a dispersed air-water system within a spouted column with a concentric draft tube and a conical base is simulated using CFD based on a two–fluid Euler–Euler (E-E) modeling framework and k-ε two-equation turbulence closures. The interaction between the dispersed gas phase and the continuous liquid phase is characterized by bubble–liquid interphase forces (drag, turbulent dispersion and lift forces). The Ishii-Zuber drag model [1] and Grace adjusted drag model [2], the latter represented by: GraceDpg Grace dense D C C , , are compared for their capability to match experimental gas hold- up. Numerical results of Reynolds-averaged Navier-Stokes equations with k-ε two-equation turbulence closures models when compared with
Pironti experimental data [3] indicated that both drag models, predicted the air hold-up within experimental error. Furthermore, Ishii-Zuber liquid-gas drag model consistently provided better agreement of experimental results; it correctly determines the hold-up within 0.14%. Numerical agreement with adjusted Grace liquid-gas drag model, is exponent dependent 4 p 0.5, turning down that the best computed hold-up is within 0.44%. for p 0.5.
2015-12-07
2015-12-07
2011-04-14
Article
Jaime. A. Riera Ortiz, Susana Zeppieri, Luis Rojas-Solorzano, Sylvana Derjani-Bayeh; 2011; Evaluation of Interphase Drag Models for the Determination of Gas Hold-Up of an Air-Water System in a Spouted Bed using CFD, http://nur.nu.edu.kz/handle/123456789/877
http://nur.nu.edu.kz/handle/123456789/877
en
oai:nur.nu.edu.kz:123456789/8782018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Analysis of Current Situation in Municipal Waste Management and Implementation of Decision Support Software in Astana, Kazakhstan
Inglezakis, V.
Rojas-Solorzano, L.
Kim, J.
Moustakas, K.
Aitbekova, A.
Ismailova, A.
Shorakyzy, G.
Kystauova, A.
Abirov, A.A.
Serikbayev, N.S.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
municipal solid waste
waste management
The city of Astana, capital of Kazakhstan with population of 804,474 generates approximately 1.39 kg/inh./day of municipal solid waste while collection rate is higher than 72% (MSW). An MBT plant of planned capacity of 600-800 tn/day and a new landfill cell of about 2 million tones are in place. Preliminary studies showed that the MSW composition is as follows: food and garden waste 29.5%, plastics 18.5%, paper 13%, glass 14.5%, textiles 9.5%, metals 0.9% and others 14.1%. About 23-34 tons of recyclables (paper, metal, glass, PET bottles, HDPE film, HDPE plastic, etc.) is separated in the existing MBT daily. In 2014 it is planned to implement separate waste collection in places of waste accumulation and a waste separation at source system. The purpose of the study is to assess the current situation of municipal solid waste in Astana and implement a Decision Support Software tool developed by the research team in order to analyse data, compare alternative waste management scenarios and propose a holistic approach in solid waste management planning. The latest available data on waste generation, composition and existing infrastructure were used in order to identify the baseline situation. This is the first research of this type conducted in Kazakhstan
2015-12-07
2015-12-07
2014
Article
Inglezakis V., Rojas-Solorzano L., Kim J., Moustakas K., Aitbekova A., Ismailova A., Shorakyzy G., Kystauova A., Abirov A.A., Serikbayev N.S.; 2014; Analysis of Current Situation in Municipal Waste Management and Implementation of Decision Support Software in Astana, Kazakhstan; http://nur.nu.edu.kz/handle/123456789/878
http://nur.nu.edu.kz/handle/123456789/878
en
oai:nur.nu.edu.kz:123456789/8792018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
Design Optimization of an Oil-Air Catch Can Separation System
Abilgaziyev, Anuar
Nogerbek, Nurbol
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
CFD
Oil Catch Can
Positive Crankcase Ventilation
Motor Oil Droplets
Mesh Refinement
Two-Phase Flow
Lagrangian-Eulerian
The Positive Crankcase Ventilation (PCV) system in a car engine is designed to lower the pressure in the crankcase, which otherwise could lead to oil leaks and seal damage. The rotation of crankshaft in the crankcase causes the churn up of oil which conducts to occurrence of oil droplets which in turn may end in the PCV exhaust air intended to be re-injected in the engine admission. The oil catch can (OCC) is a device designed to trap these oil droplets, allowing the air to escape from the crankcase with the lowest content of oil as possible and thus, reducing the generation and emission of extra pollutants during the combustion of the air-fuel mixture. The main purpose of this paper is to optimize the design of a typical OCC used in many commercial cars by varying the length of its inner tube and the relative position of the outlet from radial to tangential fitting to the can body. For this purpose, CFD parametric analysis is performed to compute a one-way coupled Lagrangian-Eulerian two-phase flow simulation of the engine oil droplets driven by the air flow stream running through the device. The study was performed using the finite volume method with second-order spatial discretization scheme on governing equations in the Solid Works-EFD CFD platform. The turbulence was modelled using the k-ɛ model with wall functions. Numerical results have proved that maximum efficiency is obtained for the longest inner tube and the tangential position of the outlet; however, it is recommended further investigation to assess the potential erosion on the bottom of the can under such a design configuration
2015-12-07
2015-12-07
2015-10-27
Article
Anuar Abilgaziyev, Nurbol Nogerbek, Luis Rojas-Solórzano; 2015; Design Optimization of an Oil-Air Catch Can Separation System; http://nur.nu.edu.kz/handle/123456789/879
http://nur.nu.edu.kz/handle/123456789/879
en
Journal of Transportation Technologies
oai:nur.nu.edu.kz:123456789/8802018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Technical and economic prefeasibility study of mini-hydro power plants in Venezuela. Case study: El Valle River
Trejo, Victor
Diaz, Gabriela
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Renewable energies
prefeasibility analysis
hydric resource
The technical and economic feasibility of the installation of a mini-hydroelectric power plant on El Valle River in Venezuela is assessed. Special attention is paid to modeling Venezuela’s energetic and economic scenarios. Sensitivity, risk and emission analyses are also carried out. The results of the study show very attractive economic indicators, such as a 280.3% internal rate of return and a 0.4 years pay-back period. The positive results of the study are indication that clean energies could find very fertile scenarios in countries such as Venezuela, where the advantages of their application may not be evident
2015-12-07
2015-12-07
2015-04
Article
Trejo Victor, Diaz Gabriela, Rojas-Solorzano L.; 2015; Technical and economic prefeasibility study of mini-hydro power plants in Venezuela. Case study: El Valle River; http://nur.nu.edu.kz/handle/123456789/880
http://nur.nu.edu.kz/handle/123456789/880
en
7th International Exergy, Energy and Environment Symposium
oai:nur.nu.edu.kz:123456789/8812018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Technical-Economic Prefeasibility Assessment of an off-grid Mini-Hydro Power Plant for an Agribusiness Resort in Kaduna Nigeria
Adamu, Victor
Ampofo, Nana
Pramono Jati, Ario Panggi
Tulabing, Ryan
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Mini-hydro
pre-feasibility
clean energy
green-house-gas
Nigeria
Clean energy technologies are beginning to receive attention in Nigeria to offset the increasing greenhouse gas emissions. These emissions are associated to the wide use of small-scale fossil-fuel-powered generators by about 55% of its 180-million people yet to be connected to the grid. While a large hydropower potential exists in Nigeria, even above the total electricity demand of the country, by 2013 this technology only accounted for about 32% of the total installed generation capacity connected to the grid. Previous studies have limited results in terms of technical, economic and environmental evidences that can drive choices towards small hydro and other clean energy projects for users and technology providers in Nigeria. This study uses the RETScreen Software to analyse the technical, economic and environmental aspects of a proposed mini-hydro power plant on the Tuwan River, to supply part of the energy needs of Tuwan Agribusiness Resort (TAR) located in Madakiya district, a rural community in Kaduna State, Nigeria. The volumetric flow and gross head of the chosen river were measured and the power generation system design yielded a 21kW power output, capable to partially offset the present use of diesel generators and achieve a 307.4 tCO2 equivalent GHG emission reduction. The financial analysis showed an attractive Internal Rate of Return (IRR) of 68.1% and NPV of 568,178 USD (11% discount rate), owing to the high potential of the project to attract grants and tax rebates, which were put into consideration in the financial analysis. This study is important for Tuwan Agribusiness Resort, an agribusiness service provision outfit with a potential to create over 1000 jobs when fully operational
2015-12-07
2015-12-07
2015-04
Article
Adamu Victor, Ampofo Nana, Pramono Jati Ario Panggi, Tulabing Ryan, Rojas Solorzano Luis; 2015; Technical-Economic Prefeasibility Assessment of an off-grid Mini-Hydro Power Plant for an Agribusiness Resort in Kaduna Nigeria; http://nur.nu.edu.kz/handle/123456789/881
http://nur.nu.edu.kz/handle/123456789/881
en
7th International Exergy, Energy and Environment Symposium
oai:nur.nu.edu.kz:123456789/8822018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Technical and economic prefeasibility analysis of residential solar PV system in South Kazakhstan
Assamidanov, Anuar
Nogerbek, Nurbol
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Solar photovoltaics
renewable energy
prefeasibility analysis
RETScreen
In the family of the renewable technologies, photovoltaic (PV) systems today attract considerable attention (Dornfeldt, 2013). However, on-grid PV market is not a profitable sector by itself. It is dependent on the governmental support, which still must stimulate investment with subsidies. Thus, this paper presents the technical and economic prefeasibility analysis of implementing a residential photovoltaic system in South Kazakhstan, using the clean energy project analysis tool RETScreen® V.4. The different systems available for PV cells are considered, however, with the climatic conditions in South Kazakhstan, the study focuses on polycrystalline solar cells (Poly-Si) due to its optimal specifications for the region. Furthermore, local company Astana Solar has implemented a production line of Poly-Si photovoltaic modules using Kazakhstani silicon (Astana Solar, 2012), which could make the project even more attractive to the country.
In the analysis presented, solar resource in South Kazakhstan was estimated using solar radiation data from NASA Surface Meteorology and Solar Energy. For a 6.6 kWp system, installed in the roof of a home, it is found that 8 834 MWh of electric energy is exported to the grid in average per year. The suitability of city-level Feed in Tariffs (FITs) to promote solar photovoltaic panels in Kazakhstan is included in the analysis, despite it is very recent and had not been thoroughly examined yet (Ministry of Energy of Kazakhstan, 2014). Several different economic and financial indicators were calculated, such as the Internal Rate of Return (IRR), Net Present Value (NPV), Benefit-Cost (B-C) ratio, Cost of Energy Production (CEP) and Simple Payback (SP). All indicators for all sites explored in South Kazakhstan showed favorable conditions for deployment of the proposed residential solar PV system. The highest IRR of 17.9%, NPV of $14523 and B-C ratio of 9.65 was observed in Shymkent and the lowest IRR of 16%, NPV of $11366 and B-C ratio of 7.84 was observed in Taraz. Meanwhile, it can be observed that Shymkent got the shortest SP period of 9.9 years and Taraz got the longest payback period of 10.8 years.
The technical and economic analysis shows also that the implementation of an additional 50% subsidy on total initial cost recently approved, affected very positively the PV-based generation system in southern regions. Therefore, it is found that all southern Kazakhstan is a fertile territory to implement on-grid residential projects
2015-12-07
2015-12-07
2015-04
Article
Assamidanov Anuar, Nogerbek Nurbol, Rojas-Solorzano L.; 2015; Technical and economic prefeasibility analysis of residential solar PV system in South Kazakhstan; http://nur.nu.edu.kz/handle/123456789/882
http://nur.nu.edu.kz/handle/123456789/882
en
7th International Exergy, Energy and Environment Symposium
oai:nur.nu.edu.kz:123456789/8832018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Technical-Economic Assessment of Energy Efficiency Measures in a Mid-Size Industry
Benavides, Sara
Bitosova, Maria
Gregorio, Javier
Welschbilling, Aubin
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Energy Efficiency
prefeasibility analysis
mid-size industry
RETScreen
The industry sector is facing many challenges such as global competition, energy pricing, environmental impact amongst others. Consequently, the necessity of energy efficiency measures has become evident; framing the objective of this project as to assess the technical and economic pre-feasibility of implementing energy efficiency measures in a dairy products manufacturing company located at the south of the Reunion Island with the help of RETSCreen ® a Clean Energy Project Analysis Software. The scope of the project is focused in one of the nine buildings where the company accomplishes different production processes, specifically in the ultra-high temperature pasteurization facility building (UHT)
2015-12-07
2015-12-07
2015-04
Article
Benavides Sara, Bitosova Maria, Gregorio Javier, Welschbilling Aubin, Rojas-Solorzano L.; 2015; Technical-Economic Assessment of Energy Efficiency Measures in a Mid-Size Industry; http://nur.nu.edu.kz/handle/123456789/883
http://nur.nu.edu.kz/handle/123456789/883
en
7th International Exergy, Energy and Environment Symposium
oai:nur.nu.edu.kz:123456789/8842018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_826
Technical and economical prefeasibility study of a solar water heating (SWH) system in an apartment building in Cape Town
Idowu, Olugbeminiyi
Ige, Toluwalope
Legenski, Nicole
Mustafa, Amin A.
Rojas-Solorzano, L.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
Solar Water Heaters
Cape Town
RETScreen
Prefeasibility
Glazed solar collectors
Unglazed solar colletors
Electricity saving
Solar power has significant potential to reduce reliance on conventional energy sources in South Africa. A prefeasibility study for a communal solar water heating system (SWHS) is performed for an apartment building in the Cape Town area. Energetic-economic modelling of the system is performed via the calculation of the solar fraction, and fundamental indicators of the financial analysis such as internal rate of return (IRR), net present value (NPV), and benefit-cost ratio. Results indicate that a SWHS with a solar fraction of 32% and a benefit-cost ratio of 3.05 is realizable. Additionally, sensitivity analysis of financial results with respect to incentive rebate amount and electricity escalation rate is performed
2015-12-07
2015-12-07
2015-04
Article
Idowu Olugbeminiyi, Ige Toluwalope, Legenski Nicole, Mustafa Amin A., Rojas-Solorzano L.; 2015; Technical and economical prefeasibility study of a solar water heating (SWH) system in an apartment building in Cape Town; http://nur.nu.edu.kz/handle/123456789/884
http://nur.nu.edu.kz/handle/123456789/884
en
7th International Exergy, Energy and Environment Symposium, Valenciennes, France; 04/2015
oai:nur.nu.edu.kz:123456789/8852018-08-15T03:49:45Zcom_123456789_79com_123456789_67col_123456789_826
3D CFD Modeling Investigation of Potential Vortex Formation at the Intakes of Caruachi Powerhouse
Marcano, A.
Rojas-Solorzano, L.
Reyes, M.
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
CFD
In this paper, the 3-D CFD simulation of the free-surface flow approaching the
intakes of Caruachi Powerhouse is presented. The aim of the investigation is to determine
whether or not vortex structures are likely to appear from the water surface through the intakes, as the result of the presence of cofferdams placed few meters upstream of the intakes. The presence of cofferdams was a note of concern with regard to the effects they might have on the turbine intakes once the hydroelectric central starts operating. In all the considered conditions, results did not show neither strong surface vortices in the proximities of the Power House intakes, nor air entrainment-entrapment towards the intakes, which reflects the safe operation of the turbines in the presence of the cofferdams. The latter added in decision taking on leaving the cofferdams submerged instead of removing them, which resulted in cost savings for the project
2015-12-07
2015-12-07
2004-04
Article
A. Marcano, L. Rojas-Solórzano, M. Reyes; 2004; 3D CFD Modeling Investigation of Potential Vortex Formation at the Intakes of Caruachi Powerhouse; http://nur.nu.edu.kz/handle/123456789/885
http://nur.nu.edu.kz/handle/123456789/885
en
INTERNATIONAL CONFERENCE ONHYDRAULICS OF DAMS AND RIVER STRUCTURES, TEHRAN, IRAN; 04/2004
oai:nur.nu.edu.kz:123456789/8862018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Experimental Characterization of straight compound-channel turbulent field
Azevedo, Ricardo
Rojas-Solorzano, L.
Leal, João
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
2D Laser Doppler Velocimeter
Straight compound-channel flows have been studied by many authors, mainly concerned with mean flow variables. Detailed information on the complex turbulent field of these flows is still scarce. In the present paper, high data rate measurements were obtained for the streamwise and vertical velocity components, using a 2D Laser Doppler Velocimeter in a experimental compound flume. The filtered velocities time series allowed the computation of relevant turbulence statistics: autocorrelation functions, dissipation spectra, turbulence scales and dissipation rate. The results are analyzed by comparison with universal laws drawn for isotropic turbulent 2D fully developed open-channel flow. The presence of strong secondary currents does not affect the universal law in the floodplain, as long as the constants are changed. In the main channel the 3D behavior of the flow is more pronounced and the universal laws fail to reproduce accurately the experimental results
2015-12-07
2015-12-07
2012-06
Article
Ricardo Azevedo, Luis Rojas-Solórzano, João Leal; 2012; Experimental Characterization of straight compound-channel turbulent field; http://nur.nu.edu.kz/handle/123456789/886
http://nur.nu.edu.kz/handle/123456789/886
en
2nd European IAHR Congress; 06/2012
oai:nur.nu.edu.kz:123456789/8872018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Transient Two-Phase-Flow Model for Predicting Column Formation in Intermittent Gas Lift Systems
Sandoval, Sarita
Rojas-Solorzano, L.
Gasbarri, Sandro
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
The major objective of this work is to generate a mathematical model, allowing the prediction of mixture density, liquid holdup, the pressure gradient in the pipe and the real column size. This is useful for optimizing cycle times and the amount of gas required to lift the fluids and to improve the diagnostic and simulation software of IGL wells
2015-12-07
2015-12-07
2005-06-20
Article
Sarita Sandoval, Luis Rojas Solórzano, Sandro Gasbarri; 2005; Transient Two-Phase-Flow Model for Predicting Column Formation in Intermittent Gas Lift Systems; http://nur.nu.edu.kz/handle/123456789/887
http://nur.nu.edu.kz/handle/123456789/887
en
SPE Latin American and Caribbean Petroleum Engineering Conference, Rio de Janeiro, Brazil, 20 – 23 June 2005
oai:nur.nu.edu.kz:123456789/8882018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Teaching how to use the CFD Approach by an Example: Hydrodynamics within a Passenger Car Compartment in Motion
Rojas-Solorzano, L.
García, Nelson
Polanco, Geanette
Research Subject Categories::TECHNOLOGY::Engineering mechanics
mechanical engineering
CFD teaching
Flow visualization
recirculation zones
The CDF methodology is applied to the study of the air flow around a 2-D car and its interaction with the cabin internal air. The flow visualization or computational works
enable engineers to calculate different car characteristics like drag coefficient, external and internal air flow patterns, etc. Therefore, the teaching of this approach to student is a very important task to take into account in the formation process of new engineers. This work shows the numerical simulation of a specific passenger car compartment configuration solving the Navier-Stokes equations along with the k-e turbulence model
using the finite volume method. The indoor air flow is produced by the interaction between the cabin inner air with the external flow through two glass windows (one in the front seat and one in the back seat). This configuration represents a common situation for the passenger car compartment. The study covers two different car speeds, 50 and 100 km/h. The flow field is studied in both steady state and transient conditions with time
step of 0.01 s, for both car speeds, 50 km/h and 100 km/h. The different steps of the CFD work are commented to show to the reader the distinct states that must be cover in this kind of work. As results of the detailed methodology followed, the influence
of the domain size on the flow fields is highlighted, the requirement of a better mesh quality is exposed and flow field results are analyzed using two different forms of graphic
representations. The results show the physics behavior of the flow and the presence of flow structures, as for instance, indoor air recirculation zones delimited by internal seats, as well as, the vortex presence at the back of the cabin
2015-12-07
2015-12-07
2009-08-02
Article
Geanette Polanco, Nelson García, Luis Rojas; 2009; Teaching how to use the CFD Approach by an Example: Hydrodynamics within a Passenger Car Compartment in Motion; http://nur.nu.edu.kz/handle/123456789/888
http://nur.nu.edu.kz/handle/123456789/888
en
DOI: 10.1115/FEDSM2009-78014 Conference: ASME 2009 Fluids Engineering Division Summer Meeting, At Vail, Colorado USA, Volume: 1
oai:nur.nu.edu.kz:123456789/8892018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
New borate ester based polymer electrolyte for battery application
Kottegoda, I.R.M.
Bakenov, Zhumabay
Ikuta, H.
Uchimoto, Y.
Wakihara, M.
polymer electrolyte
gel electrolytes
Safety is an indispensable feature for a battery
particularly in large scale applications. In this respect, gel
electrolytes are more attractive due to less possibility of
electrolyte leakage and safer if abused. Unfortunately,
most present gel electrolyte systems are mainly based on
polyethers which supposed to be flammable. In addition,
PEO and PPO based systems exhibit a low cation
transference number. Therefore, the seeking of novel
thermally stable and safety polymer electrolytes with
improved electrochemical behaviour is crucial. In the
present contribution, we propose a series of Li-ion
conducting polymer electrolytes based on the
poly(ethyleneglycol) (PEG) borate ester (PE-350B) and
PEG-methacrylates (PME-400 and PDE-600,
respectively) plasticized by M550B100 PEG-borate ester,
which can be characterized as a thermally stable solvent
with high flash point [1].
2015-12-08
2015-12-08
2003-01
Article
Kottegoda I.R.M., Bakenov Zhumabay., Ikuta H., Uchimoto Y., Wakihara M., 2003 The Electrochemical Society, Inc., New borate ester based polymer electrolyte for battery application
http://nur.nu.edu.kz/handle/123456789/889
en
The Electrochemical Society, Inc.
oai:nur.nu.edu.kz:123456789/8902018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Thermal modelling of a lithium-Ion aqueous battery
Adair, Desmond
Kalimuldina, Gulnur
Bakenov, Zhumabay
thermal modelling
lithium-Ion aqueous battery
Thermal modelling is presented here for a novel
lithium-ion aqueous battery [1] using the commercial
multi-physics package COMSOL with extensions
consisting of an energy balance and temperature
dependence of properties of the battery. The model is
based on the pseudo two-dimensional Doyle-Fuller-
Newman (DFN) [2, 3] battery model and a thermal,
electrochemistry coupled model, which can capture highrate
transient effects and makes the task of relating model
parameters back to physical quantities, such as diffusivity
and porosity relatively easy.
2015-12-08
2015-12-08
2013-10
Article
Adair Desmond., Kalimuldina Gulnur., Bakenov Zhumabay., 2013 The Electrochemical Society, Thermal modelling of a lithium-Ion aqueous battery
http://nur.nu.edu.kz/handle/123456789/890
en
The Electrochemical Society
oai:nur.nu.edu.kz:123456789/8912018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Development of innovative lithium metal-free lithium-ion sulfur battery for renewable energy, electric transport and electronics
Hara, Toru
Konarov, Aishuak
Kurmanbayeba, Indira
Bakenov, Zhumabay
lithium metal
sulfur cathode
lithium polysulfides
electrolyte solution
Lithium/sulfur (Li/S) battery is a promising candidate for the next generation rechargeable battery
since the negative electrode, lithium, and the cathode, sulfur, have the highest theoretical capacities
of 3862 and of 1672 mAh/g, respectively, among any other active materials, e.g., graphite (372
mAh/g) or LiCoO2 (274 mAh/g, only about 50% is practically available). However, there are several
challenging issues in order to realize the use of this type of next generation battery. First, the
lithium metal anode has an intrinsic safety issue, dendrite growth that can result in internal short
circuit failure. Second, the sulfur cathode is a very insulating material; therefore, sulfur-based
cathodes need a large amount of conducting additives, resulting in the decrease in the practically
available gravimetric capacity per the unit mass of cathode composite. Third, lithium polysulfides,
reduced (discharged) forms of sulfur, dissolve into an electrolyte solution, resulting in capacity
fading. For realistic battery applications, these issues from both the anode and the cathode need to
be solved or mitigated. To this end, we integrate three practically possible solutions: (1)
manufacture-friendly pre-lithiation of anode or cathode materials, (2) practically optimal choice of
conducting agent and of the method for S/conductive-agent integration, and (3) stabilization of
discharged forms of the cathode.
2015-12-08
2015-12-08
2015-01
Article
Hara Toru., Konarov Aishuak., Kurmanbayeba Indira., Bakenov Zhumabay., 2015, Development of innovative lithium metal-free lithium-ion sulfur battery for renewable energy, electric transport and electronics
http://nur.nu.edu.kz/handle/123456789/891
en
oai:nur.nu.edu.kz:123456789/8922018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_826
Economical comparison among rechargeable batteries for integrating renewable energy into electrical grids
Hara, Toru
Moldabayeva, Azhar
Korzhynbayeva, Kuralay
Melisova, Malika
Kurmanbayeva, Indira
Bakenov, Zhumabay
electrical grid
renewable energy
battery
solar and wind energy
In this paper, economical comparison is conducted among non-toxic, non-flammable rechargeable batteries for integrating renewable energy into electrical grids. Two types of recently developed non-toxic aqueous batteries, "flow assisted Zn/NiOOH battery" and "half capacitor - half battery" (AC/NiOOH and AC/NaMnO2, AC denotes activated carbon. The AC electrode can be considered "a half capacitor", and the NiOOH or NaMnO2 electrode can be considered "a half battery"), are introduced and analyzed. These newly developed energy storage devices offer less expensive solutions for large scale energy storage than conventional batteries such as lithium-ion batteries, lead-acid batteries, vanadium redox flow batteries, and nickel metal hydride batteries. A newly started aqueous battery development, flow -assist-free Zn/NiOOH battery is also presented.
2015-12-08
2015-12-08
2015-06
Article
Hara, Toru., Moldabayeva, Azhar., Korzhynbayeva, Kuralay., Melisova, Malika., Kurmanbayeva, Indira., Bakenov, Zhumabay., IMIE 2015 June 23-25, 2015, Sapporo, Japan, Economical comparison among rechargeable batteries for integrating renewable energy into electrical grids
http://nur.nu.edu.kz/handle/123456789/892
en
IMIE 2015
oai:nur.nu.edu.kz:123456789/8952018-08-15T03:49:48Zcom_123456789_79com_123456789_67col_123456789_821
Affinity binding macroporous monolithic cryogel as a matrix for extracorporeal apheresis medical devices
Mikhalovsky, S. V., Wuraola Akande, Lyuba Mikhalovska, Stuart James.
macroporous cryogel
poly (2-Hydroxyethyl Methacrylate)
poly
anti-human albumin antibody
affinity cryogel
ligand immobilisation
monolithic adsorbent
cell separation
haemocompatibility
Research Subject Categories::TECHNOLOGY::Bioengineering
Cytapheresis is an extracorporeal separation technique widely used in medicine for elimination of specific classes of blood cells from circulating blood. It has been shown recently to have clinical efficacy in various disease states, such as leukaemia, autoimmune disorders, rheumatoid arthritis, renal allograft rejection and sickle–cell anaemia. The current study was undertaken to produce an affinity-binding column, based upon a macroporous monolithic cryogel with a structure of interconnected pores, with pore size and low flow resistance potentially suitable for use in cytapheresis. The affinity column was produced from poly (2-hydroxyethyl methacrylate) PHEMA cryogels synthesized by free radical polymerization at -12°C.This study involved assessing haemolytic potential, and functionalisation of polymer matrix with biological ligands.
Haemolytic potential of poly (2-hydroxyethyl methacrylate) cryogel was established by measuring free haemoglobin after blood filtration through the column. The anti-human albumin (antibody) was chemically coupled to the epoxy derivatised monolithic cryogels and the binding efficiency of anti-human albumin (antibody) to the cryogel was determined. Our results show that approximately 100% of Red blood cells passed through the column with no evidence of haemolysis found in blood eluted. It was found that ~82% of human serum albumin was retained on the monolithic IgG anti-human albumin cryogel matrix. The obtained results suggest that poly (2-hydroxyethyl methacrylate) monolithic cryogel is a non-haemolytic material (haemocompatible matrix) capable of functionalisation with antibody and thus can be an appropriate matrix for use in extracorporeal apheresis system.
2015-12-11
2015-12-11
2015-09
Article
Wuraola Akande, Lyuba Mikhalovska, Stuart James, Sergey Mikhalovsky. Affinity Binding Macroporous Monolithic Cryogel as a Matrix for Extracorporeal Apheresis Medical Devices. International Journal of Biomedical Materials Research. Vol. 3, No. 5, 2015, pp. 56-63. doi: 10.11648/j.ijbmr.20150305.11
http://nur.nu.edu.kz/handle/123456789/895
en
International Journal of Biomedical Materials Research
oai:nur.nu.edu.kz:123456789/8962018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
Poly (2-Hydroxyethyl Methacrylate) macroporous cryogel for extracorporeal medical devices
Mikhalovsky, S. V.
Akande, Wuraola Akande
Mikhalovska, Lyuba
James, Stuart
macroporous cryogel
poly
mechanical properties
creep test
compressive modulus
Research Subject Categories::NATURAL SCIENCES::Chemistry::Physical chemistry::Surface and colloid chemistry
Poly (2-hydroxyethyl methacrylate) PHEMA monolithic cryogels were synthesized by free radical polymerization at -12°C for 18 hours and produced spongy, elastic and macroporous gel matrix. Scanning Electron Microscopy (SEM) measured structural properties of PHEMA monolithic cryogel matrix to visualize pore morphology. Mechanical properties of PHEMA monolithic cryogel such as storage modulus, compressive modulus, and creep test were measured with Dynamic mechanical analyzer (DMA). The PHEMA monolithic cryogel matrix shows ~ 97% recovery after 70% compression of cryogel and has a compressive modulus of 1.8kPa to 8.5kPa.
2015-12-11
2015-12-11
2015-08-17
Article
Wuraola Akande, Lyuba Mikhalovska, Stuart James, Sergey Mikhalovsky. Poly (2-Hydroxyethyl Methacrylate) Macroporous Cryogel for Extracorporeal Medical Devices. International Journal of Biomedical Materials Research. Vol. 3, No. 4, 2015, pp. 46-55. doi: 10.11648/j.ijbmr.20150304.12
http://nur.nu.edu.kz/handle/123456789/896
en
International Journal of Biomedical Materials Research
oai:nur.nu.edu.kz:123456789/8972018-08-15T03:49:46Zcom_123456789_79com_123456789_67col_123456789_821
Current state of chronic wound care in Kazakhstan: focus on topical treatments
Mikhalovsky, S. V.
Akhmetova, Alma
Saliev, Timur
Kulsharova, Gulsim
Nurgozhin, Talgat
chronic wound
treatment
wound dressing
Kazakhstan
Research Subject Categories::TECHNOLOGY::Chemical engineering::Chemical process and manufacturing engineering::Surface and colloid chemistry
Research Subject Categories::TECHNOLOGY::Chemical engineering
Background — The presence of chronic hard-to-heal wounds significantly affects patients’ quality of life causing pain, discomfort, decrease of mobility and consequently leads to social isolation and depression. This type of wound is more prevalent among older population. It has been estimated that up to 1-2% of the world population have this condition. The treatment of hard-to-heal wounds is expensive and long-term process, and, stresses healthcare systems of every country. Unfortunately, limited information is available about the situation with chronic wounds in Kazakhstan as the statistical data on such patients is not monitored and not registered in this country. Methods — The search was conducted by using available electronic sources, including Google Scholar, PubMed, Web of Sciences, Medline, Wiley Online Library, and Cochrane Library databases as well as hard copy versions of peer-reviewed publications in Russian, Kazakh, and English languages. Results — We have identified and analyzed current situation with wound care in the Republic of Kazakhstan. Research has demonstrated a variety of types of treatments utilized in the country, particularly the treatment of the diabetic foot.It also indicates the lack of statistics on wound care. Conclusions — The review highlights the mechanisms of wound healing process, methods for wound care, and encompasses the information available on wound healing in Republic of Kazakhstan. The article emphasizes the necessity of establishing the systemic monitoring of wound care and formation of electronic database. Apart from that, the importance of developing and manufacturing of domestic novel wound treatments have been also stressed out.
2015-12-11
2015-12-11
2015-01-16
Article
Cite as Akhmetova A, Saliev T, Kulsharova G, Nurgozhin T, Mikhalovsky S. Current state of chronic wound care in Kazakhstan: focus on topical treatments. Russian Open Medical Journal 2015; 4: e0104.
http://nur.nu.edu.kz/handle/123456789/897
en
Russian Open Medical Journal
oai:nur.nu.edu.kz:123456789/8982018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
Polyurethane–poly(2-hydroxyethyl methacrylate) semi- IPN–nanooxide composites
Mikhalovsky, S. V.
Bershtein, Vladimir A.
Gun’ko, Vladimir M.
Karabanova, Lyudmila V.
Sukhanova, Tatiana E.
Yakushev, Pavel N.
Egorova, Larisa
Turova, Anna A.
Zarko, Vladimir I.
Pakhlov, Eugene M.
Vylegzhaninad, Milana E.
semi-interpenetrating polymer
polymer composites
Polyurethane–poly
semi- IPN–nanooxide composites
Two sets of hybrid polyurethane–poly(2-hydroxyethyl methacrylate) semi-interpenetrating polymer
network–nanooxide composites with 0.25 or 3 wt% nanosilica or nanoalumina functionalised with OH,
NH2 or CHLCH2 groups were prepared. A combination of atomic force microscopy, infrared spectroscopy,
thermally stimulated depolarisation current measurement, differential scanning calorimetry and creep rate
spectroscopy analysis of the nanostructure and properties of the composites was performed. The
pronounced dynamic heterogeneity and the strong impact of oxide additives, basically suppression of the
dynamics and temperature-dependent increasing modulus of elasticity, were observed. The effects correlated with either interfacial interactions (for silica) or the nanostructure (for alumina). A low oxide content strongly affected the matrix due to the formation of an unusual cross-linked, via double covalent hybridisation of three components, structure of the nanocomposites.
2015-12-11
2015-12-11
2013-05-30
Article
RSC Advances, 2013, 3, 14560. DOI: 10.1039/c3ra40295a
http://nur.nu.edu.kz/handle/123456789/898
en
RSC Advances
oai:nur.nu.edu.kz:123456789/8992018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
The use of composite ferrocyanide materials for treatment of high salinity liquid radioactive wastes rich in cesium isotopes
Toropov, Andrey S.
Satayeva, Aliya R.
Mikhalovsky, S. V.
Cundy, Andrew B.
cesium
liquid radioactive wastes
composite
ferrocyanide
The use of composite materials based on metal ferrocyanides combined with natural mineral sorbents for treatment of high salinity Cs-containing liquid radioactive
waste (LRW) was investigated. The study indicated that among the investigated composites, the best sorption characteristics for Cs were shown by materials based on
copper ferrocyanide. Several factors affecting the removal of cesium from LRW, namely total salt content, pH and organic matter content, were also investigated. High concentrations of complexing organic matter significantly reduced
the sorption capacity of ferrocyanide sorbents.
2015-12-11
2015-12-11
2014
Article
DOI 10.1515/ract-2013-2212
http://nur.nu.edu.kz/handle/123456789/899
en
Radiochim. Acta
oai:nur.nu.edu.kz:123456789/9002018-08-15T03:50:25Zcom_123456789_79com_123456789_67col_123456789_826
Development of new type of wound dressing based on cryogel matrix with incorporated nanoparticles
Saliev, Timur
Kulsharova, Gulsim
Akhmetova, Alma
Nurgozhin, Talgat
Whitby, Ray D.L.
wound dressing
cryogel
nanoparticles
silver
gold
microwave
Research Subject Categories::TECHNOLOGY::Electrical engineering, electronics and photonics
A cryogel (polymethyl methacrylate) has been chosen as a basis for new type
of wound dressings, where incorporated silver and gold nanoparticles do provide effective
antibacterial protection [1]. This function will be enhanced by extracorporeal application of
microwave radiation in safe regime.
2015-12-11
2015-12-11
2014-08
Article
The 15th IUMRS-International Conference in Asia (IUMRS-ICA 2014) 24th (Sun.) to 30th (Sat.) August, 2014 at Fukuoka University, Fukuoka, Japan
http://nur.nu.edu.kz/handle/123456789/900
en
The 15th IUMRS-International Conference in Asia (IUMRS-ICA 2014)
oai:nur.nu.edu.kz:123456789/9012018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
New technology based on combination of cryogel and nanoparticles for wound management
Saliev, Timur
Kulsharova, Gulsim
Akhmetova, Alma
Nurgozhin, Talgat
Whitby, Ray D.L.
Mikhalovsky, S. V.
anti-microb
anti-microbial properties of noble metals
cryogel
nanoparticles
wound management
Research Subject Categories::TECHNOLOGY::Electrical engineering, electronics and photonics
The anti-microbial properties of noble metals have been
known since ancient times. The new technology allows
obtaining metal particles with programmed size and
shape. Gold and silver nanoparticles have been
employed for various bio-medical applications (1, 2, 3).
In our study we developed the method of obtaining gold
and silver nanoparticles with different shape. The
nanoparticles are to be incorporated into the cryogel,
which provides an ideal antimicrobial microenvironment
for effective wound healing.
2015-12-11
2015-12-11
2014-08
Article
Timur Saliev, Gulsim Kulsharova, Alma Akhmetova, Talgat Nurgozhin, Ray D.L. Whitby and Sergey Mikhalovsky. New Technology Based on Combination of Cryogel and Nanoparticles for Wound Management. 26th European Conference on Biomaterials, Liverpool, 31st August – 3rd September 2014
http://nur.nu.edu.kz/handle/123456789/901
en
26th European Conference on Biomaterials, Liverpool
oai:nur.nu.edu.kz:123456789/9022018-08-15T03:49:47Zcom_123456789_79com_123456789_67col_123456789_821
Antimicrobial activity of silver nanoparticles incorporated in a cryogel matrix
Illsley, Matthew
Bower, Cressida
Akhmetova, Alma
Kulsharova, Gulsim
Saliev, Timur
Nurgozhin, Talgat
Mikhalovsky, S. V.
Polymerization
antimicrobial activity of silver
Hospital acquired infections are a major financial and
societal burden with high mortality, morbidity and cost.
Such infections are caused by a number of pathogenic
and opportunistic bacteria, many of which are resistant
to front line antibiotics. To combat their emergence and
spread, new approaches have been developed such as
adding biocides to wound dressings and surgical
implants, but have met with limited success. We
proposed an innovative technology capable of
improving the clinical outcomes associated with
bacterial infection of skin, deep wounds and surgical
implants. This approach will exploit the ability of silver
nanoparticles (NPs)1 to produce antibacterial radicals
and reactive compounds. To begin with, antimicrobial
activity of NPs and cytotoxicity of materials were
tested.
2015-12-11
2015-12-11
2015-09
Article
27, h European Conference on Biomaterials, Krakow, Poland, 30t h August - 3r d September 2015
http://nur.nu.edu.kz/handle/123456789/902
en
27, h European Conference on Biomaterials, Krakow, Poland
oai:nur.nu.edu.kz:123456789/9942018-08-15T03:49:48Zcom_123456789_79com_123456789_67col_123456789_821
VELOS - A VR environment for ship applications: current status and planned extensions
Alexandros, Ginnis
Konstantinos, Kostas
Constantinos, Politis
Panagiotis, Kaklis
Research Subject Categories::TECHNOLOGY::Engineering physics
Crowd simulation
Ship Evacuation assessment
Volume 8844 of the series Lecture Notes in Computer Science pp 33-55
Virtual Environment for Life On Ships (VELOS) is a multi-user Virtual
Reality (VR) system that supports designers to assess (early in the design
process) passenger and crew activities on a ship for both normal and hectic
conditions of operations and to improve the ship design accordingly.
Realistic simulations of behavioral aspects of crowd in emergency
conditions require modeling of panic aspects and social conventions of
inter-relations. The present paper provides a description of the enhanced
crowd modeling approach employed in VELOS for the performance of ship
evacuation assessment and analysis based on the guidelines provided by
IMO's Circular MSC 1238/2007.
2016-01-06
2016-01-06
2015-04-01
Book chapter
A.I. Ginnis, K.V. Kostas, C.G. Politis and P.D. Kaklis, 2014, "VELOS - A VR environment for ship applications: current status and planned extensions", Chapter: Virtual Realities, volume 8844 of the series Lecture Notes in Computer Science pp 33-55, Springer
http://nur.nu.edu.kz/handle/123456789/994
en
Springer International Publishing
oai:nur.nu.edu.kz:123456789/9952018-08-15T03:49:48Zcom_123456789_79com_123456789_67col_123456789_821
A BEM-Isogeometric method with application to the wavemaking resistance problem of ships at constant speed
Konstantinos, Belibassakis
Theodoros, Gerostathis
Konstantinos, Kostas
Constantinos, Politis
Panagiotis, Kaklis
Alexandros, Ginnis
Christian, Feurer
Research Subject Categories::TECHNOLOGY::Electrical engineering, electronics and photonics
wave resistance
Boundary element methods
Ships
In the present work IsoGeometric Analysis (IGA), initially proposed by
Hughes et al (2005), is applied to the solution of the boundary integral
equation associated with the Neumann-Kelvin (NK) problem and the
calculation of the wave resistance of ships, following the formulation by
Brard (1972) and Baar & Price (1988). As opposed to low-order panel
methods, where the body is represented by a large number of quadrilateral
panels and the velocity potential is assumed to be piecewise constant (or
approximated by low degree polynomials) on each panel, the isogeometric
concept is based on exploiting the NURBS basis, which is used for
representing exactly the body geometry and adopts the very same basis
functions for approximating the singularity distribution (or in general the
dependent physical quantities). In order to examine the accuracy of the
present method, in a previous paper Belibassakis et al (2009), numerical
results obtained in the case of submerged bodies are compared against
analytical and benchmark solutions and low-order panel method
predictions, illustrating the superior efficiency of the isogeometric
approach. In the present paper we extent previous analysis to the case of
wave-making resistance problem of surface piercing bodies. The present
approach, although focusing on the linear NK problem which is more
appropriate for thin ship hulls, it carries the IGA novelty of integrating CAD
systems for ship-hull design with computational hydrodynamics solvers.
2016-01-06
2016-01-06
2011-06-11
Article
K.A. Belibassakis, Th.P. Gerosthathis, K.V. Kostas, C.G. Politis, P.D. Kaklis, A.I. Ginnis and C. Feurer, 2011, “A BEM-Isogeometric Method with Application to the Wavemaking Resistance Problem of Ships at Constant Speed”, Proceedings of the ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2011, June 19-24, 2011, Rotterdam, The Netherlands.
978-0-7918-4438-0
http://nur.nu.edu.kz/handle/123456789/995
en
ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering
oai:nur.nu.edu.kz:123456789/9962018-08-15T03:49:48Zcom_123456789_79com_123456789_67col_123456789_821
Use of VELOS platform for modelling and accessing crew assistance and passenger grouping in ship-evacuation analysis
Konstantinos, Kostas
Alexandros, Ginnis
Constantinos, Politis
Panagiotis, Kaklis
Research Subject Categories::TECHNOLOGY::Electrical engineering, electronics and photonics
Crowd Modeling
Group Behaviors
IMO guidelines for evacuation
VELOS, which stands for “Virtual Environment for Life On Ships”, is a
multi-user VR system that aims to support designers, early in the design
process, to assess passenger and crew activities on ship and improve ship
design accordingly. VELOS functionalities provide design aids required for
both normal and hectic operational conditions. This has been accomplished
by integrating a broad range of software components in VELOS platform
which includes tools targeting geometric and VR modelling, crowd
microscopic modelling based on steering behaviours technology, as well as
communication interfaces with external computational software packages.
In the present work, we focus on the evacuation-specific functionality of
VELOS by enhancing it with passenger-grouping and crew-assistance
behaviour. This is mainly achieved by combining and extending steering
behaviours, already used within VELOS, for crowd modelling, as, e.g.,
Leader-Follow and Cohere behaviour. This enhancement allows simulating
the evacuation process more realistically and comparing results acquired for
the scenarios prescribed by the IMO, with and without the consideration of
grouping and crew-assistance behaviour.
2016-01-06
2016-01-06
2011-09-13
Article
K.V. Kostas, A.A-I Ginnis, C.G. Politis & P.D. Kaklis, 2011, “Use of VELOS platform for modelling and accessing crew assistance and passenger grouping in ship-evacuation analysis” in IMAM 2011 Genoa 13- 16th September proceedings : “Sustainable Maritime Transportation and Exploitation of Sea Resources”, Eds E. Rizzuto, C. Guedes Soares vol 2, pp. 729-736.
http://nur.nu.edu.kz/handle/123456789/996
en
CRC Press
oai:nur.nu.edu.kz:123456789/12412018-08-15T03:50:25Zcom_123456789_79com_123456789_67col_123456789_821
Influence of hydrological connectivity on winter limnology in 1 floodplain lakes 2 of the Saskatchewan River Delta, SK
MacKinnon, Brett D.
Sagin, Jay
Baulch, Helen M.
Lindenschmidt, Karl-Erich
Jardine, Timothy D.
floodplains
connectivity
isotope
remote sensing
nutrients
winter
dams
Globally, hydrological connectivity between rivers and their floodplains has been reduced by river flow management and land transformation. The Saskatchewan River Delta is North America’s largest inland delta and a hub for fish and fur production. To determine the influence of connectivity on limnology within this northern floodplain, water chemistry and stable isotopes (δ18O and δ236 H) were analyzed during the winter of 2014 in shallow lakes along a hydrological gradient. A total of five lake connectivity categories were determined by optical remote-sensing images of surface water coverage area from years of varying flood intensities. Accuracy of categories were verified by degree of 18O and 239 H enrichment within lakes. Both isotopes showed marked successional enrichment between connectivity categories with more isolated lakes exhibiting greater enrichment. Water chemistry in lakes with greater connectivity to the main channel were characterized by higher pH, dissolved oxygen, nitrates and sulfates, and lower total nitrogen, total phosphorus, and ammonium, compared to more isolated lakes. These findings illustrate how connectivity influences water chemistry in northern floodplain lakes and how it might determine the suitability of these lakes as winter refuge for fishes. Additionally, our study provides supporting evidence for the effective use of optical remote sensing imagery, an inexpensive and accessible source of data for researchers, when determining connectivity characteristics of large northern floodplain systems. Additionally, this study provides further evidence that the inundation of floodplain lakes by river water during peak discharge has an impact on the conditions within the lakes long into the winter ice-cover season. Understanding the year-round influence of river-floodplain connection is imperative for assessing potential impacts of climate change and future water regulation on such ecosystems
2016-02-17
2016-02-17
2015
Article
MacKinnon Brett D., Sagin Jay, Baulch Helen M., Lindenschmidt Karl-Erich, Jardine Timothy D.; 2015; Influence of hydrological connectivity on winter limnology in 1 floodplain lakes 2 of the Saskatchewan River Delta, SK
http://nur.nu.edu.kz/handle/123456789/1241
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:nur.nu.edu.kz:123456789/12422021-02-05T10:25:53Zcom_123456789_79com_123456789_67col_123456789_822
Integrated Approach for the Assessment and Development of Groundwater Resources in Arid Lands: Applications in the Quetta Valley, Pakistan
Sagin, Jay
Groundwater Resources
The lack of adequate field measurements (e.g., precipitation and stream flow) and
difficulty in obtaining them often hampers the construction and calibration of rainfallrunoff
models over many of the world’s watersheds, leaving key elements of the
hydrologic cycle unconstrained. We adopted methodologies that rely heavily on readily
available remote sensing datasets as viable alternatives and useful tools for assessing,
managing, and modeling the water resources of such remote and inadequately gauged
regions. The Soil and Water Assessment Tool was selected for continuous (1998–2005)
rainfall-runoff modeling of the northeast part of the Pishin Lora basin (NEPL), a
politically unstable area that lacks adequate rain gauge and stream flow data. To account
for the paucity of rain gauge and stream flow gauge data, input to the model included
satellite-based Tropical Rainfall Measuring Mission TRMM precipitation data. Modeled
runoff was calibrated against satellite-based observations including: (1) monthly
estimates of the water volumes impounded by the Khushdil Khan (latitude 30° 40'N,
longitude 67° 40'E) and the Kara Lora (latitude 30° 34'N, longitude 66° 52'E) reservoirs,
and (2) inferred wet versus dry conditions in streams across the NEPL throughout this
period. Calibrations were also conducted against observed flow reported from the Burj
Aziz Khan station at the NEPL outlet (latitude 30°20'N; longitude 66°35'E). Model
simulations indicate that (1) average annual precipitation (1998–2005), surface runoff,
and net recharge are 1,300 × 106 m3, 148 × 106 m3, and 361 × 106 m3, respectively; (2)
within the NEPL watershed, precipitation and runoff are high for the northeast
(precipitation: 194 mm/year; runoff: 38 × 106 m3/year) and northwest (134 mm/year; 26 ×
106 m3/y) basins compared to the southern basin (124 mm/year; 8 × 106 m3/year); and (3)
construction of delay action dams in the northeast and northwest basins of the NEPL
could increase recharge from 361 × 106 m3/year up to 432 × 106 m3/year and achieve
sustainable extraction. The adopted methodologies are not a substitute for traditional
approaches that require extensive field datasets, but they could provide first-order
estimates for rainfall, runoff, and recharge in the arid and semi-arid parts of the world
that are inaccessible and/or lack adequate coverage with stream flow and precipitation
data.
2016-02-17
2016-02-17
2010-12
Thesis of the employee
Jay Sagin; 2010; Integrated Approach for the Assessment and Development of Groundwater Resources in Arid Lands: Applications in the Quetta Valley, Pakistan
http://nur.nu.edu.kz/handle/123456789/1242
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
Nazarbayev University School of Engineering and Digital Sciences
oai:nur.nu.edu.kz:123456789/12462018-08-15T03:49:52Zcom_123456789_79com_123456789_67col_123456789_826
Groundwater inflow modeling for a Kazakhstan copper ore deposit
Sagin, Jay
Yerikuly, Zhaiyk
Zhaparkhanov, Slyamhan
Panichkin, Vladimir
Miroshnichenko, Oxana
Mashtayeva, Shamshagul
mining operations
Mining exploration is widely spread throughout Kazakhstan and it is an important part of the country’s economy. However, mining can create landslides, as well as both surface and groundwater pollution. The purpose of this research is to model the water movement and water volume changes for one of Kazakhstan's mining operations. In this study, we have modeled and predicted the water volume changes within a mining operation for the next 50 years, until the year 2065. The sulphide-ore mining operation, which was studied, is located in East Kazakhstan. Several mining development scenarios with groundwater volume changes were prepared. One of the modeling scenarios was related to the mining pit exploration up to a depth of 100 meters. The groundwater inflow was computed at 106.3 m3/hour, or 2551.6 m3/day for this scenario. Another modeling scenario for the same mining pit had a depth at 585 meters. The groundwater inflow for this scenario was computed at 268.6 m3/hour, or 6447.3 m3/day. Calibration and verification were provided for the modeling work, and results were compared to the water balance. The results of this work could be considered for the engineering design to drain the groundwater from the mining pit. This research work and methodology are replicable and could be applied to other mining explorations and groundwater inflow prediction analyses. The methodology can be adapted to open pit mines under similar conditions
2016-02-17
2016-02-17
2015
Article
Zhanay Sagintayev, Zhaiyk Yerikuly, Slyamhan Zhaparkhanov, Vladimir Panichkin, Oxana Miroshnichenko, Shamshagul Mashtayeva; 2015; Groundwater inflow modeling for a Kazakhstan copper ore deposit; Journal of environmentalhydrology
http://nur.nu.edu.kz/handle/123456789/1246
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:nur.nu.edu.kz:123456789/12472018-08-15T03:49:52Zcom_123456789_79com_123456789_67col_123456789_826
A geospatial model to determine patterns in river ice cover breakup and jamming behaviour
Sagin, Jay
ice cover breakup
ice jamming occurrences
In the past, both empirical and process-based attempts have been made to predict river ice behaviour, in particular ice cover breakup and ice jamming occurrences. These methods perform with varying and limited success and tend to be site specific. A method is required which can simply estimate the predisposition of river reaches to ice breakup and jamming events. This paper introduces a geospatial modelling approach which can fulfil that task and improve the predictive power of ice cover breakup and ice jamming behaviour. The geospatial model can determine the most vulnerable sections along the studied reaches to such behaviour, which are phenomena entailing hydraulic, ice morphology and fluvial geomorphology. A geospatial model clusters hydraulic characteristics (e.g. discharge or stage), ice characteristics (e.g. ice thickness
and ice type) and river geomorphological characteristics (e.g. sinuosity, slope, width, etc.) into common river features called Geomorphic Response Units (GRU). A statistical clustering technique such as principle component analysis (PCA) is used to derive these GRUs. It is assumed that certain GRUs will be more susceptible to certain ice cover behaviour, such as breakup and jamming of river ice. Data acquired along the Slave River and its delta in Canada is used to test the geospatial model. The main data sources are space-borne remote sensing MODIS imagery and traditional and local knowledge from members of the communities alongside the river, in particular Fort Resolution and Fort Smith
2016-02-17
2016-02-17
2014-08
Article
Sagin Jay; 2014; A geospatial model to determine patterns in river ice cover breakup and jamming behaviour
http://nur.nu.edu.kz/handle/123456789/1247
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:nur.nu.edu.kz:123456789/12492021-02-05T10:25:55Zcom_123456789_79com_123456789_67col_123456789_822
Relationship between 20th Century Dune Migration and Wetland Formation at Cape Cod National Seashore, Massachusetts
Sagin, Jay
Dune migration
Outer Cape Cod (Massachusetts) is dominated by active and stabilizing parabolic
and transverse dunes interspersed with numerous inter-dune wetlands. Dune migration has been significantly affected by human activities; conversely, current dune movements are affecting local populations. The objective of the reported research was to assess, using remote sensing and geographic information systems (GIS) technologies, migration of the Cape Cod dunes and the effect of dune movement on distribution of associated wetlands. Aerial photographs from 1938 through 2003 were analyzed to track individual dune movements and subsequent wetland propagation and expansion. Absolute dune movement rates during this period were computed, with a plot of dune movement as a cumulative function. One sub-problem of this study was to quantify ‘white’ areas of active moving sand and ‘dark’ areas of vegetation, in order to quantify changes in vegetative cover with wetland propagation and, conversely, vegetative disappearance with dune movement. Attempts were made to correlate the Palmer Drought Severity Index (PDSI) with dune migration. Based on review of aerial photographs, parabolic dunes have migrated 150 to 250 m since 1938, with 60% of the movement occurring between 1938 and 1977. The relation between absolute parabolic dune migration and corresponding PDSI is approximately logarithmic. Maximum dune migration is associated with PDSI values lower than –2 and reflects moderate drought conditions. Wetlands consistently trailed the dunes, and the distance of wetland movement was related to dune movement distances. Wetland migration was particularly marked from the 1950s to the 1980s. Based on review of georeferenced aerial photographs, it is concluded that marked stabilization of Cape Cod dunes occurred in the 1980s and 1990s, with renewed movement in the 21st Century. This
study provides a practical application for assessment of dune migration and vegetative
transformations over time using remote sensing and GIS technologies
2016-02-17
2016-02-17
2006-05
Thesis of the employee
Zhanay Sagintayev; 2006; Relationship between 20th Century Dune Migration and Wetland Formation at Cape Cod National Seashore, Massachusetts
http://nur.nu.edu.kz/handle/123456789/1249
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
Nazarbayev University School of Engineering and Digital Sciences
oai:nur.nu.edu.kz:123456789/12502018-08-15T03:49:52Zcom_123456789_79com_123456789_67col_123456789_826
Red Sea Rifting Controls on Groundwater Reservoir Distribution: Constraints from Geophysical, Isotopic, and Remote Sensing Data
Sturchio, Neil C.
Sagin, Jay
Becker, Richard H.
Ahmed, Mohamed
Groundwater Reservoir Distribution
Highly productive wells in the Central
Eastern Desert of Egypt are tapping groundwater
in subsided blocks of Jurassic to
Cretaceous sandstone (Taref Formation of
the Nubian Sandstone Group) and Oligocene
to Miocene sandstone (Nakheil Formation),
now occurring beneath the Red Sea coastal
plain and within the proximal basement complex.
Aquifer development is related to Red
Sea rifting: (1) rifting was accommodated by
vertical extensional displacement on preexisting
NW-SE– to N-S–trending faults forming
a complex array of half-grabens and asymmetric
horsts; and (2) subsided blocks escaped
erosion accompanying the Red Sea–related
uplift. Subsided blocks were identifi ed and
verifi ed using satellite data, geologic maps,
and fi eld and geophysical investigations. Interpretations
of very low frequency (VLF)
measurements suggest the faults acted as
conduits for ascending groundwater from the
subsided aquifers. Stable isotopic compositions
(δD: –19.3‰ to –53.9‰; δ18O: –2.7‰ to
–7.1‰) of groundwater samples from these
aquifers are interpreted as mixtures of fossil
(up to 70%) and modern (up to 65%) precipitation.
Groundwater volumes in subsided
blocks are large; within the Central Eastern
Desert basement complex alone, they are estimated
at 3 × 109 m3 and 10 × 109 m3 for the
Nakheil and Taref Formations, respectively.
Results highlight the potential for identifying
similar rift-related aquifer systems along
the Red Sea–Gulf of Suez system, and in rift
systems elsewhere. An understanding of the
distribution of Red Sea rift–related aquifers
and modern recharge contributions to these
aquifers could assist in addressing the rising
demands for fresh water supplies and water
scarcity issues in the region
2016-02-17
2016-02-17
2008-10
Article
Neil C Sturchio, Jay Sagin, Richard H Becker, Mohamed Ahmed; 2008; Red Sea Rifting Controls on Groundwater Reservoir Distribution: Constraints from Geophysical, Isotopic, and Remote Sensing Data
http://nur.nu.edu.kz/handle/123456789/1250
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:nur.nu.edu.kz:123456789/12882018-08-15T03:49:53Zcom_123456789_79com_123456789_67col_123456789_821
Assessment of a Shallow Water Model using a Linear Turbulence Model for Obstruction-Induced Discontinuous Flows
Pu, Jaan Hui
Bakenov, Zhumabay
Adair, Desmond
Research Subject Categories::TECHNOLOGY::Engineering mechanics
Shallow Water Model
Linear Turbulence Model
Assessment of the performance of a shallow water model with closure using a linear k-ε turbulence
model is made for various obstruction-induced discontinuous flows. The monotone upwind scheme of
conservative laws (MUSCL) - Hancock scheme is used, together with the Harten Lax van Leer (HLL)
approximate Riemann solver in the discretization of the finite volume shallow water model. These kinds
of models contribute to the improvement of optimized design of various processes in chemical
engineering and technology. Two obstructed flow applications are presented, namely, single obstruction
and multiple obstruction induced discontinuous flows; and the ability of the shallow water model with the
k-ε based turbulence model to predict these applications are assessed. The simulation results of the
shallow water model are compared with those found by direct numerical simulation (DNS) and
experimental measurements in the literature
2016-02-19
2016-02-19
2012
Article
Jaan Hui Pu, Zhumabay Bakenov, Desmond Adair; 2012; Assessment of a Shallow Water Model using a Linear Turbulence Model for Obstruction-Induced Discontinuous Flows; Eurasian chemico-technological journal
http://nur.nu.edu.kz/handle/123456789/1288
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:nur.nu.edu.kz:123456789/12952018-08-15T03:49:50Zcom_123456789_79com_123456789_67col_123456789_1228
The Quest for Economic Recovery: Innovative Development and KM Perspectives
Tsakalerou, Mariza
Lee, Rongbin W. B.
knowledge management
economic crisis
Most organizations respond to an economic crisis by focusing on operational efficiency and/or on intellectual
capital utilization and innovation. The conjecture is that intellectual capital confers distinct competitive
advantage to an enterprise via knowledge management and knowledge spillovers and improved
innovation capacity. Despite mixed empirical evidence to support this claim, intellectual capital and
knowledge management remain at the forefront of an organization’s agenda during an economic downturn.
Recent surveys from the field indicate some dissatisfaction with practical knowledge management. These
findings are difficult to interpret because at the same time organizations appear to adopt the position that
management of knowledge resources is extremely important from a strategic perspective. The objective
of this chapter is to provide some new perspectives on what drives success in the knowledge economy
and to demonstrate how knowledge management is the ideal response to the challenge of innovation
2016-02-19
2016-02-19
2015
Article
Mariza Tsakalerou, Rongbin W. B. Lee; 2015; The Quest for Economic Recovery: Innovative Development and KM Perspectives; Knowledge Management for Competitive Advantage During Economic Crisis
http://nur.nu.edu.kz/handle/123456789/1295
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:nur.nu.edu.kz:123456789/12962018-08-15T03:49:51Zcom_123456789_79com_123456789_67col_123456789_821
Developing an Understanding of the Steps Involved in Solving Navier– Stokes Equations
Adair, Desmond
Jaeger, Martin
Navier– Stokes equations
Mathematica
This article describes how Mathematica can be used to develop
an understanding of the basic steps involved in solving Navier–
Stokes equations using a finite-volume approach for
incompressible steady-state flow. The main aim is to let students
follow from a mathematical description of a given problem
through to the method of solution in a transparent way. The wellknown
“driven cavity” problem is used as the problem for testing
the coding, and the Navier–Stokes equations are solved in
vorticity-streamfunction form. Building on what the students were
familiar with from a previous course, the solution algorithm for
the vorticity-streamfunction equations chosen was a relaxation
procedure. However, this approach converges very slowly, so
another method using matrix and linear algebra concepts was
also introduced to emphasize the need for efficient and
optimized code
2016-02-19
2016-02-19
2015
Article
Desmond Adair, Martin Jaeger; 2015; Developing an Understanding of the Steps Involved in Solving Navier– Stokes Equations; The Mathematica Journal
http://nur.nu.edu.kz/handle/123456789/1296
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Cluster management: from economic agglomeration to leveraging innovation
Tsakalerou, Mariza
Clusters
Innovation
Regional Development
Businesses clusters are defined as geographical concentrations of
vertically and horizontally integrated firms in related lines of business. As
such, clusters are complex and dynamic structures that are continuously
evolving. Cluster management consists of the development of monitoring
actions and interventions aiming to improve their capacities and capabilities.
Strong clusters can promote economic growth by tapping into the unused
business potential of a region. As the clustering effect evolves from mere
economic agglomeration into an innovation agent, it is important to focus on
ways to leverage this potential for development. The objective of this article
is to provide a panorama of the issues and the challenges facing cluster
management today
2016-02-19
2016-02-19
2015
Article
Mariza Tsakalerou; 2015; Cluster management: from economic agglomeration to leveraging innovation; European Scientific Journal
1857- 7431
http://nur.nu.edu.kz/handle/123456789/1297
en
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Dimensions of proximity: clusters, intellectual capital and knowledge spillovers
Tsakalerou, Mariza
Clusters
Intellectual Capital
Knowledge Management
Clusters of geographical concentrations of related business firms are
assumed to confer competitive advantages to their members and their regions
via knowledge management and knowledge spillovers of tacit knowledge.
Despite mixed empirical evidence to support these claims, business clusters
remain at the forefront of regional development policies. Past research
indicates that cluster success factors may be distinct in different parts of the
world, in different economies and in different stages of their development.
Yet most studies focus on the success of a cluster as a whole and do not
assess the impact of cluster membership on a single firm due to the absence
of commonly agreed metrics. To address this problem, this article shifts the
focus from mere spatial proximity to the flow of information in business
networks and to the production, dissemination and absorption of knowledge.
In this context, information flow in business clusters is aided and abetted by
spatial proximity but the flow itself is the important success factor.
Validation of the hypothesis that the advantage of clusters has to do with
information flows, intellectual capital and knowledge spillovers will open
new avenues in cluster research
2016-02-19
2016-02-19
2015
Article
Mariza Tsakalerou; 2015; Dimensions of proximity: clusters, intellectual capital and knowledge spillovers; European Scientific Journal
1857- 7431
http://nur.nu.edu.kz/handle/123456789/1298
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Heat transfer enhancement of a periodic array of isothermal pipes
Leontiou, Theodoros
Ikram, Magzhan
Beketayev, Kenes
Fyrillas, Marios
Solid slab with periodic array of pipes
Convective heat transfer
Laplace equation
gener- alized Schwarz-Christoffel transformation
Shape Optimization
Optimum shapes of pipes
Critical Thickness of slab
Critical depth of the pipes
We address the problem of two-dimensional heat conduction in a solid slab whose
upper and lower surfaces are subjected to uniform convection. In the midsection of the
slab there is a periodic array of isothermal pipes of general cross section. The main
objective of this work is to find the optimum shapes of the pipes that maximize the
Shape Factor (heat transport rate). The Shape Factor is obtained by transforming the
periodic array of pipes into a periodic array of strips, using the generalized Schwarz-
Christoffel transformation, and applying the collocation boundary element method on
the transformed domain. Subsequently we pose the inverse problem, i.e. finding the
shape that maximizes the Shape factor given the perimeter of the pipes. For large Biot
number the optimum shapes are in agreement with the isothermal case, i.e. circular for
sufficiently small perimeters/heat transfer, and elongated towards the surfaces of the
slab for larger perimeters/heat transfer. Furthermore, for the isothermal case, we were
able to discover a new family of optimum shapes for large thickness of the slab and large perimeters, which do not have their maximum width on the horizontal axis of symmetry. For small Biot number the optimum pipes are flatter than the isothermal ones for a given perimeter. The flatness becomes more apparent for larger perimeters. Most important, for large perimeters there exists a critical thickness which is characterized by maximum heat transfer rate. This is further investigated using the finite element method to obtain the critical thickness of a slab and the critical depth of the periodic array of circular pipes
2016-02-19
2016-02-19
2016-02-18
Article
Theodoros Leontiou, Magzhan Ikram, Kenes Beketayev, Marios M. Fyrillas; 2016; Heat transfer enhancement of a periodic array of isothermal pipes; International Journal of Thermal Sciences
http://nur.nu.edu.kz/handle/123456789/1299
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Numerical simulation of droplet formation in a microchannel device
Rojas-Solórzano, L.
Rodríguez Granado, Katherine V.
Anna, Shelley L.
Verma, Salman
microfluidics
microchannel
droplet formation
CFD
The formation of droplets is a phenomenon with particular importance in
the development of industrial emulsions. The quality of these compounds
is associated with droplet size and stability over time. Anna et al. (2003)
developed a methodology named ¨flow focusing¨ to improve droplet
formation processes for engineering applications. In this work,
Computational Fluid Dynamics (CFD) based techniques are used to assess
the capacity of a pseudo-2D numerical model to reproduce water droplets
formation within silicon oil, as obtained in Anna et al.’s experiments.
Average time of droplet onset obtained via numerical analysis was 1.5 times
larger than observed experimentally, whereas droplets convection velocity
and diameter predictions differed by 40-45% and 60%, respectively.
Nevertheless, calculated velocity profiles downstream the discharge slot
reproduced the expected free-jet shear layer according to outer/inner flow
ratio.
2016-06-21
2016-06-21
2013
Article
Katherine V. Rodríguez Granado, Shelley L. Anna, Luis R. Rojas-Solórzano and Salman Verma. 2013. Numerical simulation of droplet formation in a microchannel device. The International Journal of Multiphysics.
http://nur.nu.edu.kz/handle/123456789/1640
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A free-standing sulfur/nitrogen-doped carbon nanotube electrode for high- performance lithium/sulfur batteries
Zhao, Yan
Yin, Fuxing
Zhang, Yongguang
Zhang, Chengwei
Mentbayeva, Almagul
Umirov, Nurzhan
Xie, Hongxian
Bakenov, Zhumabay
lithium/sulfur battery
sulfur/nitrogen-doped carbon nanotube composite cathode
free-standing electrode
A free-standing sulfur/nitrogen-doped carbon nanotube (S/N-CNT) composite prepared via a simple solution
method was first studied as a cathode material for lithium/sulfur batteries. By taking advantage of the self-weaving
behavior of N-CNT, binders and current collectors are rendered unnecessary in the cathode, thereby simplifying its
manufacturing and increasing the sulfur weight ratio in the electrode. Transmission electronic microscopy showed
the formation of a highly developed core-shell tubular structure consisting of S/N-CNT composite with uniform
sulfur coating on the surface of N-CNT. As a core in the composite, the N-CNT with N functionalization provides a
highly conductive and mechanically flexible framework, enhancing the electronic conductivity and consequently
the rate capability of the material.
2016-07-08
2016-07-08
2015-12
Article
Zhao, Yan., Yin, Fuxing., Zhang, Yongguang., Zhang, Chengwei., Mentbayeva, Almagul., Umirov, Nurzhan., Xie, Hongxian., Bakenov, Zhumabay., A free-standing sulfur/nitrogen-doped carbon nanotube electrode for high- performance lithium/sulfur batteries, Nanoscale Research Letters a Springer Open Journal (2015), DOI 10.1186/s11671-015-1152-4, http://nur.nu.edu.kz/handle/123456789/1675
http://nur.nu.edu.kz/handle/123456789/1675
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Nanoscale Research Letters a Springer Open Journal (2015)
oai:nur.nu.edu.kz:123456789/16852018-08-15T03:49:54Zcom_123456789_79com_123456789_67col_123456789_826
Simultaneous Spectrum Sensing and Data Transmission for Multi-User MIMO Cognitive Radio Systems
Miridakis, Nikolaos I.
Tsiftsis, Theodoros A.
Alexandropoulos, George C.
Debbah, M´erouane
Cognitive radio
detection probability
imperfect channel estimation
spatial multiplexing
spectrum sensing
We present a multi-user multiple-input multipleoutput
(MIMO) cognitive radio system consisting of a secondary
receiver that deploys spatial multiplexing to decode signals from
multiple secondary transmitters, under the presence of primary
transmissions. The secondary receiver carries out minimum
mean-squared error detection to decode the secondary data
streams, while it performs spectrum sensing at the remaining
signal to capture the potential presence of primary activity.
Assuming Rayleigh fading as well as the realistic cases of channel
fading time variation and channel estimation errors, we present
novel closed-form expressions for important system measures,
namely, the detection and false-alarm probabilities as well as
the transmission power of the secondary nodes. The enclosed
numerical results verify the accuracy of the presented analysis.
2016-08-11
2016-08-11
2016
Conference Paper
Nikolaos I. Miridakis, Theodoros A. Tsiftsis, George C. Alexandropoulos, and M´erouane Debbah; 2016; Simultaneous Spectrum Sensing and Data Transmission for Multi-User MIMO Cognitive Radio Systems; http://nur.nu.edu.kz/handle/123456789/1685
http://nur.nu.edu.kz/handle/123456789/1685
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On the Energy Efficiency in Multi-user Multi-relay Coded Network
Qi, Nan
Xiao, Ming
Tsiftsis, Theodoros A.
Cao, Phuong L.
Skoglund, Mikael
Li, Lixin
Energy Efficiency
Coded Network
In this paper, the energy efficiency (EE) of a
cooperative diversity system with maximum diversity network
coding (MDNC) is studied. In the considered system, channel
state information (CSI) is only available at the receivers for all
the channels. We formulate the problem of maximizing the EE
under the constraint on the outage probability. The problem
is NP-hard due to the non-convexity of the outage probability
function and the nonlinear fractional structure of the introduced
EE. To solve the optimization problem efficiently, first, the outage
probability function is tightly approximated as a log-convex form
in the high signal-to-noise ratio (SNR) region. Further, based on
the fractional programming, we transform the introduced EE
into a subtractive-form, which is proved to be a convex form. The
tradeoff between outage probability and EE is given. The results
show that our power allocation (PA) policy can substantially
increase the EE. We show that EE can be increased if more
relays forward the messages. Additionally, we also investigate
the effect of the relay locations on the EE and demonstrate that
the increase in the transmission distance in the first hop causes
the loss of the EE. The loss can be reduced by our PA policy
2016-08-11
2016-08-11
2016
Conference Paper
Nan Qi, Ming Xiao, Theodoros A. Tsiftsis, Phuong L. Cao, Mikael Skoglund, and Lixin Li; 2016; On the Energy Efficiency in Multi-user Multi-relay Coded Network; 23rd International Conference on Telecommunicationsl; http://nur.nu.edu.kz/handle/123456789/1686
http://nur.nu.edu.kz/handle/123456789/1686
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Energy Efficient Switching between Data Transmission and Energy Harvesting for Cooperative Cognitive Relaying Systems
Miridakis, Nikolaos I.
Tsiftsis, Theodoros A.
Alexandropoulos, George C.
Debbah, M´erouane
Cognitive relaying systems
cooperative spectrum sensing
detection probability
energy efficiency
energy harvesting
A dual-hop cognitive (secondary) relaying system
incorporating collaborative spectrum sensing to opportunistically
switch between data transmission and energy harvesting is
introduced. The secondary relays, first scan the wireless channel
for a primary network activity, and then convey their reports
to a secondary base station (SBS). Afterwards, the SBS, based
on these reports and its own estimation, decides cooperatively
the presence of primary transmission or not. In the former
scenario, all secondary relays start to harvest energy from the
transmission of one or more primary nodes. In the latter scenario,
the system initiates secondary communication via a best relay
selection policy. The performance of the proposed scheme is
thoroughly investigated by assuming realistic channel conditions,
i.e., non-identical link-distances and outdated channel estimation,
while its overall energy consumption is evaluated, indicating the
efficiency of the switching approach.
2016-08-11
2016-08-11
2016
Conference Paper
Nikolaos I. Miridakis, Theodoros A. Tsiftsis, George C. Alexandropoulos, and M´erouane Debbah; 2016; Energy Efficient Switching between Data Transmission and Energy Harvesting for Cooperative Cognitive Relaying Systems; IEEE ICC 2016 - Green Communications Systems and Networks
http://nur.nu.edu.kz/handle/123456789/1687
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oai:nur.nu.edu.kz:123456789/16882018-08-15T03:49:54Zcom_123456789_79com_123456789_67col_123456789_826
Resource Allocation for Licensed/Unlicensed Carrier Aggregation MIMO Systems
Tsinos, Christos G.
Foukalas, Fotis
Tsiftsis, Theodoros A.
Carrier Aggregation
MIMO
LTE-A
Unlicensed Transmission
Interference Nulling
Resource Allocation
Carrier Selection
In this paper a novel Carrier Aggregation (CA)
scheme is proposed for downlink MIMO LTE-A Systems. The
proposed approach achieves increased transmission rates by
establishing the communication links via both licensed and
unlicensed bands without generating or experiencing interference
to/from the users of the latter bands. To that end, a rate
optimization problem is defined and solved subject to the previous
zero interference constraints, a total power constraint and a
maximum number of aggregated bands constraint. It turns
out that the previous problem is a Mixed Integer Non Linear
Programming (MINLP) one that requires an exhaustive search
procedure in order to be solved. To tackle this, an optimal low
complexity method is proposed based on the Lagrange dual
decomposition. The performance of the original (MINLP) and
the low-complexity proposed techniques is verified via indicative
simulations
2016-08-11
2016-08-11
2016
Conference Paper
Christos G. Tsinos, Fotis Foukalas, Theodoros A. Tsiftsis; 2016; Resource Allocation for Licensed/Unlicensed Carrier Aggregation MIMO Systems; IEEE Wireless Conference and Networking Conference (WCNC 2016) Track 1: PHY and Fundamentals; http://nur.nu.edu.kz/handle/123456789/1688
http://nur.nu.edu.kz/handle/123456789/1688
en
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oai:nur.nu.edu.kz:123456789/16892018-08-15T03:49:57Zcom_123456789_79com_123456789_67col_123456789_826
Energy Detection Based Spectrum Sensing over Enriched Multipath Fading Channels
Bagheri, Alireza
Sofotasios, Paschalis C.
Tsiftsis, Theodoros A.
Ho-Van, Khuong
Loupis, Michael I.
Freear, Steven
Valkama, Mikko
Energy detection
radio systems
Energy detection has been for long constituting the
most popular sensing method in RADAR and cognitive radio
systems. The present paper investigates the sensing behaviour of
an energy detector over Hoyt fading channels, which have been
extensively shown to provide rather accurate characterization of
enriched multipath fading conditions. To this end, a simple series
representation and an exact closed-form expression are firstly
derived for the corresponding average probability of detection for
the conventional single-channel communication scenario. These
expressions are subsequently employed in deriving novel analytic
results for the case of both collaborative detection and squarelaw
selection diversity reception. The derived expressions have
a relatively tractable algebraic representation which renders
them convenient to handle both analytically and numerically.
As a result, they can be utilized in quantifying the effect of
fading in energy detection based spectrum sensing and in the
determination of the trade-offs between sensing performance and
energy efficiency in cognitive radio communications. Based on
this, it is shown that the performance of the energy detector
depends highly on the severity of fading as even slight variations
of the fading conditions affect the value of the average probability
of detection. It is also clearly shown that the detection
performance improves substantially as the number of branches
or collaborating users increase. This improvement is substantial
in both moderate and severe fading conditions and can practically
provide full compensation for the latter cases
2016-08-12
2016-08-12
2016
Conference Paper
Alireza Bagheri, Paschalis C. Sofotasios2, Theodoros A. Tsiftsis, Khuong Ho-Van, Michael I. Loupis, Steven Freear, and Mikko Valkama; 2016; Energy Detection Based Spectrum Sensing over Enriched Multipath Fading Channels; IEEE Wireless Conference and Networking Conference (WCNC 2016) Track 1: PHY and Fundamentals; http://nur.nu.edu.kz/handle/123456789/1689
http://nur.nu.edu.kz/handle/123456789/1689
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oai:nur.nu.edu.kz:123456789/16902018-08-15T03:49:57Zcom_123456789_79com_123456789_67col_123456789_826
Antenna Beamforming for Energy Harvesting in Cognitive Radio Networks
Liu, Huidong
Chen, Jin
Ding, Guoru
Tsiftsis, Theodoros A.
Rowell, Corbett
Cooperative spectrum sensing
energy harvesting
energy cooperation
cognitive radio networks
energy beamforming
In this paper, a cooperative cognitive radio network
(CRN) with energy harvesting capabilities of its secondary users
is considered. Specifically, cooperative spectrum sensing and
multi-antenna beamforming are employed to improve the sensing
performance and the energy transfer efficiency, respectively. In
our approach, a homogeneous CRN scenario is studied where the
optimal sensing probability of each second user (SU) is obtained
to maximize the control center (CC) throughput while satisfying
the energy causality and primary user (PU) collision constraints.
An iterative algorithm is proposed to obtain the optimal charging
time. Numerical results depict that in an energy constrained
scenario, cooperative spectrum sensing with beamforming performs
much better than cooperative spectrum sensing without
beamforming in terms of increased system throughput
2016-08-12
2016-08-12
2016
Conference Paper
Huidong Liu, Jin Chen, Guoru Ding, Theodoros A. Tsiftsisz, and Corbett Rowell; 2016; Antenna Beamforming for Energy Harvesting in Cognitive Radio Networks; http://nur.nu.edu.kz/handle/123456789/1690
http://nur.nu.edu.kz/handle/123456789/1690
en
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oai:nur.nu.edu.kz:123456789/19382018-08-15T03:50:01Zcom_123456789_79com_123456789_67col_123456789_821
Shape-optimization of 2D hydrofoils using an Isogeometric BEM solver
Konstantinos, Kostas
Ginnis, A.I.
Politis, C.G.
Kaklis, P.D.
Isogeometric Analysis
NURBS
Potential Flows
Lifting Flows
Shape optimization
In this paper, an optimization procedure, based on an Isogeometric BEM solver for the potential
ow, is developed and used for the shape optimization of hydrofoils. The formulation of the
exterior potential-
ow problem reduces to a Boundary-Integral Equation (BIE) for the associated
velocity potential exploiting the null-pressure jump Kutta condition at the trailing edge. The
numerical solution of the BIE is performed by an Isogeometric Boundary-Element Method (BEM)
combining a generic B-splines parametric modeler for generating hydrofoil shapes, using a set of
eight parameters, the very same basis of the geometric representation for representing the velocity
potential and collocation at the Greville abscissas of the knot vector of the hydrofoil's B-splines
representation. Furthermore, the optimization environment is developed based on the geometric
parametric modeler for the hydrofoil, the Isogeometric BEM solver and an optimizer employing
a controlled elitist genetic algorithm. Multi-objective hydrofoil shape optimization examples are
demonstrated with respect to the criteria i) maximum lift coefficient and ii) minimum deviation
of the hydrofoil area from a reference area.
2016-11-25
2016-11-25
2016-06-29
Article
K.V. Kostasa, A.I. Ginnisb, C.G. Politisc, P.D. Kaklis; 2016; Shape-optimization of 2D hydrofoils using an Isogeometric BEM solver; Computer-Aided Design; http://nur.nu.edu.kz/handle/123456789/1938
http://nur.nu.edu.kz/handle/123456789/1938
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Computer-Aided Design. Elsevier
oai:nur.nu.edu.kz:123456789/19932018-08-15T03:50:07Zcom_123456789_79com_123456789_67col_123456789_821
VELOS: A VR Platform for Ship-Evacuation Analysis
Ginnis, A.I.
Kostas, Konstantinos
Politis, C.G.
Kaklis, P.D.
design for safety
evacuation analysis
ship-passenger safety
virtual reality
ship design
“Virtual Environment for Life On Ships” (VELOS) is a multi-user Virtual Reality
(VR) system that aims to support designers to assess (early in the design
Process) passenger and crew activities on a ship for both normal and hectic
Conditions of operations and to improve ship design accordingly. This paper focuses
On presenting the novel features of VELOS related to both its VR and
Evacuation-specific functionalities. These features include: i) capability of multiple
Users’ immersion and active participation in the evacuation process, ii)
Real-time interactivity and capability for making on-the-fly alterations of environment
Events and crowd-behavior parameters, iii) capability of agents and
Avatars to move continuously on decks, iv) integrated framework for both the
Simplified and the advanced method of analysis according to the IMO/MSC 1033
Circular, v) enrichment of the ship geometrical model with a topological model
Suitable for evacuation analysis, vi) efficient interfaces for the dynamic specification and handling of the required heterogeneous input data, and vii) post
Processing of the calculated agent trajectories for extracting useful information
For the evacuation process. VELOS evacuation functionality is illustrated using
Three evacuation test cases for a ro-ro passenger ship.
2016-11-29
2016-11-29
2010
Article
A.I. Ginnisa, K.V. Kostasa, C.G. Politisb, P.D. Kaklis; 2010; VELOS: A VR Platform for Ship-Evacuation Analysis; Computer-Aided Design; http://nur.nu.edu.kz/handle/123456789/1993
http://nur.nu.edu.kz/handle/123456789/1993
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Computer-Aided Design. Elsevier
oai:nur.nu.edu.kz:123456789/20032018-08-15T03:50:26Zcom_123456789_79com_123456789_67col_123456789_821
Ship-Hull Shape Optimization with a T-spline based BEM-Isogeometric Solver
Kostas, Konstantinos
Ginnis, A.I.
Politis, C.G.
Kaklis, P.D.
T-spline
Wave-resistance
Shape-optimization
Ship-hull
In this work, we present a ship-hull optimization process combining a T-spline based parametric ship-hull model and an Isogeometric Analysis (IGA) hydrodynamic solver for the calculation of ship wave resistance. The surface representation of the ship-hull instances comprise one cubic T-spline with extraordinary points, ensuring C2C2 continuity everywhere except for the vicinity of extraordinary points where G1G1 continuity is achieved. The employed solver for ship wave resistance is based on the Neumann–Kelvin formulation of the problem, where the resulting Boundary Integral Equation is numerically solved using a higher order collocated Boundary Element Method which adopts the IGA concept and the T-spline representation for the ship-hull surface. The hydrodynamic solver along with the ship parametric model are subsequently integrated within an appropriate optimization environment for local and global ship-hull optimizations against the criterion of minimum resistance.
2016-11-29
2016-11-29
2014
Article
K.V. Kostasa, A.I. Ginnisb, C.G. Politisa, P.D. Kaklis; 2014; Ship-Hull Shape Optimization with a T-spline based BEM-Isogeometric Solver; Computer Methods in Applied Mechanics and Engineering; http://nur.nu.edu.kz/handle/123456789/2003
http://nur.nu.edu.kz/handle/123456789/2003
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Computer Methods in Applied Mechanics and Engineering
oai:nur.nu.edu.kz:123456789/20042018-08-15T03:50:01Zcom_123456789_79com_123456789_67col_123456789_821
A BEM-ISOGEOMETRIC method for the ship wave-resistance problem
Belibassakis, K.A.
Gerostathis, Th.P.
Kostas, Konstantinos
Politis, C.G.
Kaklis, P.D.
Ginnis, A.I.
Feurer, C.
Isogeometric Analysis
high-order BEM
Neumann-Kelvin problem
NURBS
CAD-CFD integration
In the present work IsoGeometric Analysis is applied to the solution of the Boundary
Integral Equation associated with the Neumann-Kelvin problem and the calculation of the
wave resistance of ships. As opposed to low-order panel methods, where the body is
represented by a large number of quadrilateral panels and the velocity potential is assumed
to be piecewise constant (or approximated by low degree polynomials) on each panel, the
isogeometric concept is based on exploiting the same NURBS basis, used for representing
exactly the body geometry, for approximating the singularity distribution (and, in general,
the dependent physical quantities). In order to examine the accuracy of the present method,
numerical results obtained in the case of submerged and surface piercing bodies are
* Corresponding author. Tel: (+30) 2107721138, Fax: (+30) 2107721397, e-mail: kbel@fluid.mech.ntua.gr
2
compared against analytical solutions, experimental data and predictions provided by the
low-order panel or other similar methods appeared in the pertinent literature, illustrating
the superior efficiency of the isogeometric approach. The present approach by applying
Isogeometric Analysis and Boundary Element Method to the linear NK problem has the
novelty of combining modern CAD systems for ship-hull design with computational
hydrodynamics tools.
2016-11-29
2016-11-29
2012
Article
K.A. Belibassakis, Th.P. Gerostathis, K.V. Kostas, C.G. Politis, P.D. Kaklis, A.I. Ginnis and C. Feurer; 2012; A BEM-ISOGEOMETRIC method for the ship wave-resistance problem; Ocean Engineering; http://nur.nu.edu.kz/handle/123456789/2004
http://nur.nu.edu.kz/handle/123456789/2004
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Attribution-NonCommercial-ShareAlike 3.0 United States
Ocean Engineering
oai:nur.nu.edu.kz:123456789/20052018-08-15T03:50:01Zcom_123456789_79com_123456789_67col_123456789_821
Isogeometric Boundary-Element Analysis for the Wave-Resistance Problem using T-splines
Ginnis, A.I.
Kostas, Konstantinos
Politis, C.G.
Kaklis, P.D.
Belibassakis, K.A.
Gerostathis, Th.P.
Scott, M.A.
Hughes, T.J.R
T-splines
Isogeometric analysis
BEM
Wave resistance
In this paper we couple collocated Boundary Element Methods (BEM) with unstructured analysis suitable
T-spline surfaces for solving a linear Boundary Integral Equation (BIE) arising in the
context of a ship-hydrodynamic problem, namely the so-called Neumann-Kelvin problem, following
the formulation by Brard (1972) [1] and Baar & Price (1988) [2]. The local-refinement capabilities
of the adopted T-spline bases, which are used for representing both the geometry of the hull and
approximating the solution of the associated BIE, in accordance with the Isogeometric concept
proposed by Hughes et al. (2005) [3], lead to a solver that achieves the same error level for many
fewer degrees of freedom as compared with the corresponding NURBS-based Isogeometric-BEM
solver recently developed in Belibassakis et al. (2013) [4]. In this connection, this paper makes a
step towards integrating modern CAD representations for ship-hulls with hydrodynamic solvers of
improved accuracy and efficiency, which is a prerequisite for building efficient ship-hull optimizers.
2016-11-29
2016-11-29
2014
Technical Report
A.I. Ginnisa, , K.V. Kostasb, C.G. Politisb, P.D. Kaklisa,c, K.A. Belibassakisa, Th.P. Gerostathisb, M.A. Scottd, T.J.R Hughes; 2014; Isogeometric Boundary-Element Analysis for the Wave-Resistance Problem using T-splines; Elsevier; http://nur.nu.edu.kz/handle/123456789/2005
http://nur.nu.edu.kz/handle/123456789/2005
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
Computer Methods in Applied Mechanics and Engineering. Elsevier
oai:nur.nu.edu.kz:123456789/20082018-08-15T03:50:06Zcom_123456789_79com_123456789_67col_123456789_821
Renewable Energy Distribution in Cooperative Cellular Networks with Energy Harvesting
Reyhanian, Navid
Shah-Mansouri, Vahid
Maham, Behrouz
Yuen, Chau
Renewable Energy
In this paper, we propose a novel online centralized
algorithm for energy cooperation among energy harvesting capable
base stations (BSs) in multi-tier cellular networks. BSs are connected
to the non-renewable source used by a BS when it cannot
harvest sufficient energy to serve its connected users. BSs with
the extra harvested energy operate cooperatively and share their
surplus energy with BSs that have not harvested sufficient energy.
To stimulate BSs with energy deficit to use the shared energy
of other BSs, an energy pricing framework is established which
results in reducing of the non-renewable energy consumption. We
formulate the problem of maximizing the fairness of the renewable
energy distribution. The closed-form of energy share given to
each BS with energy deficit is found, by which the renewable
energy distribution fairness is maximized. Energy is shared by
the smart grid. The problem of minimizing the smart grid usage
cost for distributing energy is formulated and an online algorithm
is proposed to approximate its solution. Simulation results show
that the approximate algorithm reduces the non-renewable energy
consumption significantly and reduces the cost of smart grid usage
near to the optimal solution.
2016-11-29
2016-11-29
2015
Article
Navid Reyhanian, Vahid Shah-Mansouri, Behrouz Maham, and Chau Yuen; 2015; Renewable Energy Distribution in Cooperative Cellular Networks with Energy Harvesting; the 26th Personal, Indoor and Mobile Radio Communications Conference (IEEE PIMRC); http://nur.nu.edu.kz/handle/123456789/2008
http://nur.nu.edu.kz/handle/123456789/2008
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
IEEE Xplore
oai:nur.nu.edu.kz:123456789/20112018-08-15T03:50:09Zcom_123456789_79com_123456789_67col_123456789_821
A Matching-Game-Based Energy Trading for Small Cell Networks with Energy Harvesting
Reyhanian, Navid
Maham, Behrouz
Shah-Mansouri, Vahid
Yuen, Chau
Batteries
Smart grids
Energy harvesting
Energy consumption
Wireless networks
Land mobile radio
Deploying small cells in cellular networks, as a technique
for capacity and coverage enhancement, is an indispensable
characteristic of future cellular networks. In this paper, a novel
online decentralized algorithm for enabling energy trading in multitier
cellular networks with selfish energy harvesting capable base
stations (BSs) is proposed. A BS uses the non-renewable energy
when it cannot harvest sufficient energy to serve its connected users.
To minimize the non-renewable energy consumption, we establish
a framework for trading energy such that BSs with energy deficit
are stimulated to compensate their energy shortage with the extra
harvested energy of other BSs. BSs with energy deficit are assigned
to BSs with extra harvested energy by using matching theory. The
extra harvested energy is distributed by the smart grid. Along
with energy trades, BSs gain more profit and their utility functions
enhance. Simulation results show that the waste of energy due
to limited batteries and the non-renewable energy consumption
decreases considerably when the proposed algorithm is applied
2016-11-29
2016-11-29
2015
Article
Navid Reyhanian, Behrouz Maham, Vahid Shah-Mansouri, and Chau Yuen; 2015; A Matching-Game-Based Energy Trading for Small Cell Networks with Energy Harvesting; 2015 IEEE 26th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC); http://nur.nu.edu.kz/handle/123456789/2011
http://nur.nu.edu.kz/handle/123456789/2011
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
2015 IEEE 26th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC)
oai:nur.nu.edu.kz:123456789/20122018-08-15T03:50:00Zcom_123456789_79com_123456789_67col_123456789_821
Joint Machine-Type Device Selection and Power Allocation for Buffer-Aided Cognitive M2M Communication
Darabi, Mostafa
Maham, Behrouz
Saad, Walid
Mehbodniya, Abolfazl
Adachi, Fumiyuki
Buffer-aided cognitive M2M communication
machine-type device selection
power allocation
5G network
In this paper, a cognitive machine-to-machine
(M2M) communication network is considered, in which a cellular
network shares the spectrum with the M2M communication
network with M machine-type devices (MTDs), one half-duplex
relay, and one MTD gateway for data gathering. One key
challenge is that in the future 5G wireless networks, there will
be billions of those small MTDs, and therefore, a MTD selection
protocol is required for managing data transmission between
MTDs. A joint buffer-aided MTD selection and power allocation
protocol is proposed to maximize the MTDs’ sum-rate provided
that the induced interference to the cellular network is limited.
In particular, in the proposed scheme, at each time slot and
each subcarrier, the cognitive M2M network optimally decides
on whether to be silent or to select either the relay or one of the
MTDs for data transmission. To this end, for each MTD, there
exists a buffer at the relay to avoid data loss. The closed-form
expressions for the power coefficients of MTDs are calculated.
Simulation results show that the proposed policy improves the
sum-rate of the CM2M network in comparison with the other
proposed schemes for M2M communication without buffer
2016-11-29
2016-11-29
2015
Article
Mostafa Darabiy, Behrouz Mahamyz, Walid Saad, Abolfazl Mehbodniyax, and Fumiyuki Adachi; 2015; Joint Machine-Type Device Selection and Power Allocation for Buffer-Aided Cognitive M2M Communication; The 26th Personal, Indoor and Mobile Radio Communications Conference (IEEE PIMRC); http://nur.nu.edu.kz/handle/123456789/2012
http://nur.nu.edu.kz/handle/123456789/2012
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
The 26th Personal, Indoor and Mobile Radio Communications Conference (IEEE PIMRC)
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