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temperature-reduction
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A computational fluid dynamics (CFD) approach to modeling of pervaporation in thin membrane channels
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Shayegh, M ; Azad, R. R ; Sharif University of Technology
2006
Abstract
A comprehensive model for pervaporation in thin membrane channels was developed to study the effect of changing temperature and concentration on mass flux. This model consists of momentum, energy and species mass balances along and across the membrane in the flow channel. A computational fluid dynamics (CFD) code was written in C++ programming language to solve the coupled non-linear transport equations in the channel by finite volume method. The Semi-Implicit Pressure Link Equation (SIMPLE) CFD algorithm is used to modify the dependent variables in each of the iterations. The effect of variation of temperature and concentration on transport and thermodynamic properties were considered by...
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
With new technologies, processor power density is dramatically increased which results in high temperature. Temperature has significant impact on reliability, performance, power consumption and cooling costs. This alarming trend underscores the importance of temperature management methods in system design. Recently, various research efforts have been focused on addressing thermal issues. Due to mobility, cost and size constraints and reliability requirements, the embedded systems do not warrant use of modern cooling mechanisms such as heat sink and fan. This caused the thermal issues to be more prominent in embedded domain. This study aims at introducing thermal management techniques for...
Peak Temperature Recduction in 3D NoCs using Task Migration
, M.Sc. Thesis Sharif University of Technology ; Hessabi, Shaahin (Supervisor)
Abstract
Combination of 3D stacking and network-on-chip (NoC), known as 3D NoC, has some advantages such as reduced propagation delay, chip area and interconnect, and power consumption, and bandwidth increase. Despite these advantages, the increased power density per chip area due to area decrease causes thermal problems in 3D NoCs to be more critical than 2D NoCs. Therefore, design of temperature management algorithms is essential for these systems. One of the dynamic thermal management techniques is task migration that balances generated thermal among cores.In this thesis, we propose a task migration scheme using feedback control for 3D NoCs. The main purpose of this scheme is to decrease the peak...
Near wellbore thermal effects in a tight gas reservoir: Impact of different reservoir and fluid parameters
, Article Journal of Unconventional Oil and Gas Resources ; Volume 16 , 2016 , Pages 1-13 ; 22133976 (ISSN) ; Holmgrün, C ; Calogirou, A ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Temperature changes in and around the wellbore could lead to significant well performance and flow assurance issues. Despite its importance, near wellbore temperature change due to gas production and its importance on well performance is not well understood. Reduction of temperature in the near well bore section, could potentially lead to hydrate formation and as a result reduction of well performance. This work is aimed at evaluating the thermal behaviour in the near wellbore region of a low to tight permeability gas reservoir (ranging between 0.02 and 10 mD) during its natural depletion. The study is conducted by using a thermal-compositional simulator. The process required to simulate...
Mesoporous nanostructured Ni/MgAl2O4 catalysts: Highly active and stable catalysts for syngas production in combined dry reforming and partial oxidation
, Article International Journal of Hydrogen Energy ; Volume 44, Issue 21 , 2019 , Pages 10427-10442 ; 03603199 (ISSN) ; Nematollahi, B ; Rezaei, M ; Baghalha, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this paper, the combination of dry reforming and partial oxidation of methane on nickel catalysts supported on mesoporous MgAl2O4 was investigated. The support was prepared by a facile sol-gel route using propylene oxide as a gelation agent. The characterizations of the catalysts were performed by BET, XRD, TPR, TPO, TPH, UV–vis, CO-dispersion, SEM and TEM techniques. In addition, the effects of nickel content, reaction and reduction temperatures, feed ratio and the GHSV value on the physicochemical and catalytic properties were studied. The results revealed that the nickel content had an optimum value of 7.5 wt% and the catalyst with this content of nickel exhibited the highest activity....
Chemical durability of metallic copper nanoparticles in silica thin films synthesized by sol-gel
, Article Journal of Physics D: Applied Physics ; Volume 41, Issue 23 , November , 2008 ; 00223727 (ISSN) ; Sharif University of Technology
2008
Abstract
In this study, chemical durability of metallic copper nanoparticles dispersed in sol-gel silica thin films was investigated by exposing the films to air after a reduction process. At first, heat treatment in air for 1 h produced silica films containing crystalline cupric oxide nanoparticles agglomerated on the film surface. Subsequently, reduction of the oxidized films in a reducing environment of N2-H2 for another 1 h at temperatures of 400, 500 and 600 °C resulted in the formation of crystalline metallic Cu nanoparticles diffused in the silica matrix. The time evolution of the surface plasmon resonance absorption peak of the reduced Cu nanoparticles was studied after the reduction...