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Experimental investigation of a multi-effect active solar still: The effect of the number of stages
, Article Applied Energy ; Volume 137 , 2015 , Pages 46-55 ; 03062619 (ISSN) ; Feilizadeh, M ; Jafarpur, K ; Feilizadeh, M ; Rahimpour, M. R ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this work, the effect of the number of stages on the productivity of a multi-effect active solar still was experimentally investigated for the first time. Moreover, system performances in continuous and non-continuous modes were compared. For this purpose, indoor experiments were conducted on 4 similar solar still devices with different stages (1-4 stages) in order to accurately control the environmental conditions. In addition, water production was hourly measured during the whole 24-h experiment. The results show that with increased number of stages, distillate production can be predicted with a quadratic function. Moreover, adding a maximum of 6 and 10 additional stages can...
Experimental investigation of characteristic curve for gas-lift pump
, Article Journal of Petroleum Science and Engineering ; Volume 62, Issue 1 , 2014 , Pages 156-170 ; ISSN: 09204105 ; Raffiee, A. H ; Saidi, M. H ; Sharif University of Technology
Abstract
Using gas-liquid lifting pumps is a quite different technology for pumping two or three phase flows rather than other types of pumping systems. Therefore, finding performance characteristic chart for this type of pumping system seems to be necessary. In this type of pumping system, the liquid phase is pushed upward by the compressed air which has been injected in the bottom of upriser pipe of the pump. Therefore, compressed air acts as the driving force in gas lifting pumps instead of moving parts in ordinary pumps. It can be concluded that the definition of characteristic curve used for ordinary pump is not very appropriate for this type of pumping system. In this study, it has been...
Comparison and optimization of conjugated linoleic acid production by Lactobacillus plantarum and Lactobacillus plantarum subsp. plantarum
, Article Scientia Iranica ; Volume 24, Issue 3 , 2017 , Pages 1272-1280 ; 10263098 (ISSN) ; Alemzadeh, I ; Vossoughi, M ; Sharif University of Technology
Sharif University of Technology
2017
Abstract
Conjugated Linoleic Acid (CLA) was produced from castor oil using washed cells of Lactobacillus plantarum PTCC 1058 and Lactobacillus plantarum subsp. plantarum PTCC1745 as the catalyst. Under the optimal reaction conditions, the washed cells of Lactobacillus plantarum PTCC1058 produced 1661.26 mg of CLA/L reaction mixture (36% yield of production) from 4.6 mg/ml of castor oil after using 15% (w/v) cell for 121 h. The resulting CLA was a mixture of two CLA isomers, cis-9, trans-11 (or trans-9, cis-11)-octadecadienoic acid (CLA1, 44% of total CLA) and trans-10, cis-12-octadecadienoic acid (CLA2, 46% of total CLA). The total production of CLA is extracellular in all of the reactions performed...
Simulation of startup operation of an industrial twin-shaft gas turbine based on geometry and control logic
, Article Energy ; Volume 183 , 2019 , Pages 1295-1313 ; 03605442 (ISSN) ; Saidi, M. H ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this paper, a transient model is developed to simulate the start-up operation of an industrial twin-shaft gas turbine based on real geometry and control logic. The components’ characteristic curves of the studied gas turbine were generated with the aid of CFD simulation tools and according to the real geometry of each component. The control logic of the studied gas turbine was simplified and coupled with the developed engine performance model. Also, the gas turbine actuators including variable inlet guide vanes, compressor bleed valves, and fuel valves were simulated so that their concurrent effects on the gas turbine transient behavior can be captured precisely. Moreover, the air-cooled...
Impact of solar energy on the integrated operation of electricity-gas grids
, Article Energy ; Volume 183 , 2019 , Pages 844-853 ; 03605442 (ISSN) ; Hajibandeh, N ; Shafie khah, M ; Catalão, J. P. S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Photovoltaic energy is one of the clean and efficient energies which has been developing quickly in the last years. As the penetration of solar plants is increasing in the electricity network, new problems have arisen in network operation. This paper models a high penetration factor of solar energy in the electricity network and investigates the impact of solar energy growth on both the generation schedule of different power plants and in the natural gas transmission network. Fuel management of gas power plants is modeled through simulation of the natural gas transmission network. To this end, an increase in the penetration of solar energy in the electricity network inevitably leads to a...
Cooperative search and localization of ground moving targets by a group of UAVs considering fuel constraint
, Article Scientia Iranica ; Volume 26, Issue 5 B , 2019 , Pages 2784-2804 ; 10263098 (ISSN) ; Effati, M ; Motie, M ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
A cooperative task allocation and search algorithm is proposed to find and localize a group of ground-based moving targets using a group of Unmanned Air Vehicles (UAVs) working in a decentralized manner. It is assumed that targets have RF emissions. By using an algorithm including Global Search (GS), Approach Target (AT), Locate Target (LT), and Target Reacquisition (TR) modes, UAVs cooperatively search the entire parts of a desired area, approach to the detected targets, locate the targets, and search again to find the targets that stop transmitting their RF emissions during the localization process, respectively. In the GS mode, UAVs utilize a cost function to select the best zone for...
Cooperative search and localization of ground moving targets by a group of UAVs considering fuel constraint
, Article Scientia Iranica ; \Volume 26, Issue 5 B , 2019 , Pages 2784-2804 ; 10263098 (ISSN) ; Effati, M ; Motie, M ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
A cooperative task allocation and search algorithm is proposed to find and localize a group of ground-based moving targets using a group of Unmanned Air Vehicles (UAVs) working in a decentralized manner. It is assumed that targets have RF emissions. By using an algorithm including Global Search (GS), Approach Target (AT), Locate Target (LT), and Target Reacquisition (TR) modes, UAVs cooperatively search the entire parts of a desired area, approach to the detected targets, locate the targets, and search again to find the targets that stop transmitting their RF emissions during the localization process, respectively. In the GS mode, UAVs utilize a cost function to select the best zone for...
Computer modeling of the operating room ventilation performance in connection with surgical site infection
, Article Scientia Iranica ; Volume 27, Issue 2 , 2020 , Pages 704-714 ; Saidi, M. H ; Ahmadi, G ; Sharif University of Technology
Sharif University of Technology
2020
Abstract
The primary source of surgical site infection is the deposition of flakes released from the exposed skin of surgical staff or the patient on the exposed surgical wound. In this study, a computational model for simulating air ow and thermal conditions in an operating room is developed, and transport and deposition of particulate contaminants near the wound are analyzed. The results show the formation of a thermal plume over the wound tissue, which is typically at a higher temperature than the surrounding. The thermal plume protects the wound from the deposition of contaminants. In addition, the computational model predicts an optimum value for the inlet air velocity that is mainly maintaining...
Optimization of a novel photovoltaic thermal module in series with a solar collector using Taguchi based grey relational analysis
, Article Solar Energy ; Volume 215 , 2021 , Pages 492-507 ; 0038092X (ISSN) ; Parcheforosh, A ; Salari, A ; Ma, T ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The solar collectors absorb solar irradiation and then produce thermal energy; however, they cannot generate electrical power. Electricity and thermal energy can be produced by the photovoltaic thermal module, simultaneously, while the outlet temperature of the photovoltaic thermal module is not usually high enough to provide thermal requirements of a building such as hot water or space heating. This work proposes a novel compound system created by the connection of a solar collector in series with a photovoltaic thermal module to resolve the issue of low outlet temperature in the photovoltaic thermal module and lack of electrical power in solar collectors. To examine the feasibility of this...
A novel design and performance optimization methodology for hydraulic Cross-Flow turbines using successive numerical simulations
, Article Renewable Energy ; Volume 169 , 2021 , Pages 1402-1421 ; 09601481 (ISSN) ; Durali, M ; Khakrand, M. H ; Hoghooghi, H ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This paper introduces a new methodology for designing and optimizing the performance of hydraulic Cross-Flow turbines for a wide range of operating conditions. The methodology is based on a one-step approach for the system-level design phase and a three-step, successive numerical analysis approach for the detail design phase. Compared to current design methodologies, not only does this approach break down the process into well-defined steps and simplify it, but it also has the advantage that once numerical simulations are conducted for a single turbine, most of the results can be used for an entire class of Cross-Flow turbines. In this paper, after a discussion of the research background, we...
Multi-objective design and operation of Solid Oxide Fuel Cell (SOFC) Triple Combined-cycle Power Generation systems: Integrating energy efficiency and operational safety
, Article Applied Energy ; Volume 185 , 2017 , Pages 345-361 ; 03062619 (ISSN) ; Meghdari, M ; Rashtchian, D ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Energy efficiency is one of the main pathways for energy security and environmental protection. In fact, the International Energy Agency asserts that without energy efficiency, 70% of targeted emission reductions are not achievable. Despite this clarity, enhancing the energy efficiency introduce significant challenge toward process operation. The reason is that the methods applied for energy-saving pose the process operation at the intersection of safety constraints. The present research aims at uncovering the trade-off between safe operation and energy efficiency; an optimization framework is developed that ensures process safety and simultaneously optimizes energy-efficiency, quantified in...