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Exergoeconomic optimization of a new trigeneration system driven by biogas for power, cooling, and freshwater production
, Article Energy Conversion and Management ; Volume 205 , 2020 ; Vajdi, M ; Rostamzadeh, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Anaerobic fermentation of crop straw/animal dug can be the most appropriate solution for biomass conversion into applicable renewable energy-based fuels. However, due to the imperfection matching between the biogas combustion process and energy conversion system, a painstakingly design procedure is required to devise high-efficient energy system for capturing biogas efficiently. For this aim, a new trigeneration system driven by biogas is devised for electricity, refrigeration, and potable freshwater generation. The devised system encompasses a gas turbine (GT) cycle, a new cooling/electricity cogeneration system based on organic Rankine cycle (ORC) and ejector cooling cycle (ECC), and a...
Effect of physico-chemical properties of nanoparticles on their intracellular uptake
, Article International Journal of Molecular Sciences ; Volume 21, Issue 21 , 2020 , Pages 1-20 ; Yazdani, G ; Ashraf, S. S ; Frounchi, M ; Mashayekhan, S ; Kiani, S ; Kakkar, A ; Sharif University of Technology
MDPI AG
2020
Abstract
Cellular internalization of inorganic, lipidic and polymeric nanoparticles is of great significance in the quest to develop effective formulations for the treatment of high morbidity rate diseases. Understanding nanoparticle–cell interactions plays a key role in therapeutic interventions, and it continues to be a topic of great interest to both chemists and biologists. The mechanistic evaluation of cellular uptake is quite complex and is continuously being aided by the design of nanocarriers with desired physico-chemical properties. The progress in biomedicine, including enhancing the rate of uptake by the cells, is being made through the development of structure–property relationships in...
Sequences of fracture toughness micromechanisms in PP/CaCO3 nanocomposites
, Article Journal of Applied Polymer Science ; Volume 110, Issue 6 , 2008 , Pages 4040-4048 ; 00218995 (ISSN) ; Bagheri, R ; Zokaei, S ; Sharif University of Technology
2008
Abstract
Mechanical properties and fracture toughness micromechanisms of copolypropylene filled with different amount of nanometric CaCO3 (5-15 wt %) were studied, J-integral fracture toughness was incorporated to measure the effect of incorporation of nanoparticle into PP matrix. Crack-tip damage zones and fracture surfaces were studied to investigate the effect of nanofiller content on fracture toughness micromechanisms. It was found that nanofiller acted as a nucleating agent and decreased the spherulite size of polypropylene significantly, J-integral fracture toughness (Jc) of nanocomposites was improved dramatically. The Jc value increased up to approximately two times that of pure PP at 5 wt %...
Deriving an analytical model for hydro-magnetic micro flow controller
, Article 6th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM2008, Darmstadt, 23 June 2008 through 25 June 2008 ; Issue PART B , June , 2008 , Pages 1139-1146 ; 0791848345 (ISBN); 9780791848340 (ISBN) ; Shafii, M. B ; ASME ; Sharif University of Technology
2008
Abstract
Fluid control, namely pumping and valving, is a critical factor in the performance of micro-fluidic systems. In recent years a variety of micro-fluidic systems are developed for the purpose of miniaturizing fluid handling, and chemical analysis to develop Lab On a Chip (LOC) technology. The mentioned facts resulted in design and fabrication of a novel hydromagnetic flow controller. The idea behind this device is that magnetic particles, mixed and dispersed in a carrier liquid, can be accumulated in the form of a piston. Depending upon dragging speed of these pistons, which itself is a function of switching time, this device can be used to either increase (pumping) or decrease (valving) the...
Effect of interline power flow controller (IPFC) on interconnected power systems adequacy
, Article 2008 IEEE 2nd International Power and Energy Conference, PECon 2008, Johor Baharu, 1 December 2008 through 3 December 2008 ; 2008 , Pages 1358-1363 ; 9781424424054 (ISBN) ; Fotuhi Firuzabad, M ; Nasiri, R ; Khodaei, A ; Sharif University of Technology
2008
Abstract
This paper probes the impact of utilizing an IPFC on the reliability indices of interconnected power systems. First, a concise presentation of IPFC and its structure are provided and the reliability model of two unequally-rated parallel transmission lines equipped with IPFC is then extracted. The assumed IPFC is composed from two parallel converting bridges associated with each line. Afterwards, based-on equivalent assisting unit approach, different commonly-used adequacy indices including the loss of load expectation (LOLE), loss of energy expectation (LOEE) and system minutes (SM) are calculated. A set of numerical analyses are conducted to illustrate the sensitivity of these indices with...
Uncertainty consideration in power system reliability indices assessment using fuzzy logic method
, Article 2007 Large Engineering Systems Conference on Power Engineering, LESCOPE'07, Montreal, QC, 10 October 2007 through 12 October 2007 ; January , 2007 , Pages 305-309 ; 9781424415830 (ISBN) ; Ghafouri, A ; Sharif University of Technology
2007
Abstract
Reliability assessment of power systems is very vital particularly in the market-driven environment. As the power systems are nonlinear and large-scale systems, extracting their reliability indices involves much uncertainty. Calculation of power system reliability using stochastic methods is a complex and relatively difficult procedure. However, using fuzzy logic methods it would be possible to calculate the reliability in accordance with the existing uncertainties. In this paper, a new fuzzy logic based method is proposed to calculate the reliability indices of composite power systems. Then, the suggested method is examined on a sample network as a case study. © 2007 IEEE
Effect of the ozonation pretreatment on biogas production from waste activated sludge of tehran wastewater treatment plant
, Article Biomass and Bioenergy ; Volume 152 , 2021 ; 09619534 (ISSN) ; Ghasemi, S ; Khosravi, A ; Vossoughi, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In this study, the ozonation impact on anaerobic digestion of wasted thickened activated sludge of Tehran wastewater treatment plant has been investigated. Regarding that, the thickened activated sludge, a final solid waste of treatment plants, was subjected to ozonation pretreatment to evaluate its characteristics. Three major sludge characteristics were considered for investigating ozonation effects on anaerobic digestion. A comparison of two different ozone doses, i.e., 0.05 and 0.1 gO3 g−1TS was performed for short-term (10 days) and long-term (30 days) sludge retention times. Furthermore, biogas production, sludge composition, dewaterability, and energy balancing, were studied during...
Dynamic simulation of a solar ejector-based trigeneration system using TRNSYS-EES co-simulator
, Article Energy Science and Engineering ; Volume 10, Issue 3 , 2022 , Pages 707-725 ; 20500505 (ISSN) ; Jafari Mosleh, H ; Karami, M ; Sharif University of Technology
John Wiley and Sons Ltd
2022
Abstract
In this paper, a new configuration of a solar combined cooling, heating, and power (CCHP) system is proposed to recover the waste thermal energy of a steam power plant, which provides the cooling and heating needs of an apartment complex located in Tehran. The required energy of the system is supplied by the parabolic trough solar collectors (PTCs) and, if necessary, an auxiliary heater is also used. An ejector refrigeration cycle (ERC) and a steam Rankine cycle are used for cooling and power generation, respectively. The cycle is dynamically modeled over a year using a TRNSYS-EES co-simulator. It is found that the highest Rankine cycle efficiency is obtained in the cold months (January)...
Heat transfer and fluid flow analysis of microchannel heat sinks with periodic vertical porous ribs
, Article Applied Thermal Engineering ; Volume 205 , 2022 ; 13594311 (ISSN) ; Vafai, K ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this study, a detailed numerical analysis of the fluid flow and heat transfer of a three-dimensional microchannel is performed to evaluate the effect of using periodic vertical porous and solid ribs with various geometrical shapes, including rectangular, elliptical, isosceles triangular, backward triangular and forward triangular on the walls of this microchannel. Darcy-Brinkman-Forchheimer equations are used to model transport through the porous medium. The results for microchannels with solid ribs and with porous ribs are compared to each other. It is found that at the lowest studied inlet velocity (uin=0.25m/s), for the rib heights of Hr=0.025mm,0.05mmand0.07mm, the average Nusselt...
Fuzzy system design for automatic irrigation of agricultural fields
, Article Expert Systems with Applications ; Volume 210 , 2022 ; 09574174 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
One of the main challenges in arid and semi-arid regions is the lack of water for various purposes such as industrial and agricultural applications. The problem is even more significant in traditional agriculture. The geographical location, climatic conditions, average annual rainfall, vegetation, air pollution and turbidity, and canopy of plants are important and lead to different water consumption in plants. Therefore, proper water consumption in agriculture in most countries leads to food security and a better supply of crops. In this research, we propose a fuzzy system that has eight inputs and seven outputs. Inputs include soil moisture, relative humidity, air temperature, wind speed,...
Reliability-constrained unit commitment using stochastic mixed-integer programming
, Article 2010 IEEE 11th International Conference on Probabilistic Methods Applied to Power Systems, PMAPS 2010 ; 2010 , p. 200-205 ; ISBN: 9781420000000 ; Fotuhi-Firuzabad, M ; Aminifar, F ; Abiri-Jahromi, A ; Sharif University of Technology
Abstract
This paper proposes a stochastic mixed-integer programming (SMIP) model for the reliability-constrained unit commitment (RCUC) problem. The major objective of the paper is to examine both features of accuracy and efficiency of the proposed SMIP model of RCUC. The spinning reserve of generating units is considered as the only available reserve provision resource; however, the proposed formulation can be readily extended to comprise the other kind of reserve facilities. Expected load not served (ELNS) and loss of load probability (LOLP) are accommodated as the reliability constraints. Binding either or both reliability indices ensures the security of operation incorporating the stochastic...
Experimental and numerical investigation on the jet characteristics of spark ignition direct injection gaseous injector
, Article Applied Energy ; Volume 105 , 2013 , Pages 8-16 ; 03062619 (ISSN) ; Saidi, M. H ; Mozafari, A. A ; Hajialimohammadi, A ; Sharif University of Technology
2013
Abstract
Natural gas has widely been used as a fuel in conventional Diesel and spark ignition engines. The better understanding of injector parameters on the jet structure is helpful for the combustion optimization. This paper presents an experimental and numerical study on the jet structure of gaseous fuel injector in spark ignition direct injection engine by Schlieren technique and numerical procedure. Helium was injected through a gaseous injector at the different pressure ratios and nozzle diameters to understand the effects of nozzle geometry and pressure ratio for a dedicated correlation of CNG-SIDI injector. It was found that higher pressure ratio and exit nozzle diameter led to more tip...
Treatment of the small time instability in the finite element analysis of fluid structure interaction problems
, Article International Journal for Numerical Methods in Fluids ; Volume 71, Issue 6 , 2013 , Pages 756-771 ; 02712091 (ISSN) ; Movahhedy, M. R ; Sharif University of Technology
2013
Abstract
In this paper, the fluid-structure interaction problem in mechanical systems in which a high frequency vibrating solid structure interacts with the surrounding fluid flow is considered. Such a situation normally appears in many microelectromechanical systems like a wide variety of microfluidic devices. A different implementation of the residual-based variational multiscale flow method is employed within the arbitrary Lagrangian-Eulerian formulation. The combination of the variational multiscale method with appropriate stabilization parameters is used to handle the so-called small time step instability in the finite element analysis of the fluid part in the coupled fluid-structure interaction...
Fluid-structure interaction analysis in microfluidic devices: A dimensionless finite element approach
, Article International Journal for Numerical Methods in Fluids ; Volume 68, Issue 9 , 2012 , Pages 1073-1086 ; 02712091 (ISSN) ; Movahhedy, M. R ; Assempour, A ; Sharif University of Technology
2012
Abstract
In this paper, the so-called small time-step instability in finite element simulation of the fluid part is considered in fluid-structure interaction (FSI) problems in which a high-frequency vibrating structure interacts with an incompressible fluid. Such a situation is common in many microfluid manipulating devices. A treatment has been proposed that uses the dimensionless set of FSI governing equations in order to scale up the problem time step to a proper level that precludes the potential small time-step instability. Two-dimensional and three-dimensional finite element simulations of a mechanical micropumping device are performed to verify the efficiency of the presented approach. Solid...
Economic and environmental evaluation of different operation alternatives to aquifer thermal energy storage in Tehran, Iran
, Article Scientia Iranica ; Volume 24, Issue 2 , 2017 , Pages 610-623 ; 10263098 (ISSN) ; Bahadori, M. N ; Saidi, M. H ; Sharif University of Technology
Sharif University of Technology
2017
Abstract
Aquifers are underground porous formations containing water. Confined aquifers are surrounded by impermeable layers on top and bottom, called cap rocks and bed rocks. A confined aquifer with a very low groundwater flow velocity was considered to meet the annual cooling and heating energy requirements of a residential building complex in Tehran, Iran. Three different alternatives of Aquifer Thermal Energy Storage (ATES) were employed to meet the heating/cooling demands of the buildings. These alternatives were using ATES for: Cooling alone, heating alone by coupling with at-plate solar collectors, and cooling and heating by coupling with a heat pump. For the economic evaluation of the...
A minimally invasive robotic surgery approach to perform totally endoscopic coronary artery bypass on beating hearts
, Article Medical Hypotheses ; Volume 124 , 2019 , Pages 76-83 ; 03069877 (ISSN) ; Hanife, S ; Farahmand, F ; Behzadipour, S ; Mirbagheri, A ; Sharif University of Technology
Churchill Livingstone
2019
Abstract
The currently available robotic systems rely on rigid heart stabilizers to perform totally endoscopic coronary artery bypass (TECAB) surgery on beating hearts. Although such stabilizers facilitate the anastomosis procedure by immobilizing the heart and holding the surgery site steady, they can cause damage to the heart tissue and rupture of the capillary vessels, due to applying relatively large pressures on the epicardium. In this paper, we propose an advanced robotic approach to perform TECAB on a beating heart with minimal invasiveness. The idea comes from the fact that the main pulsations of the heart occur as excursions in normal direction, i.e., perpendicular to the heart surface. We...
A techno-economic analysis of geothermal ejector cooling system
, Article Energy ; Volume 193 , 15 February , 2020 ; Aligolzadeh, F ; Hakkaki Fard, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Ground-coupled ejector cooling (GCEC) systems have been introduced to solve the air-coupled ejector cooling (ACEC) systems problems. To date, no research study is dedicated to compare the GCEC and the ACEC systems and determine the relative payback period of the GCEC system vs. the ACEC system. Furthermore, almost all the previous studies simulated the GCEC systems by elementary models. Therefore, a comprehensive simulation is conducted to assess the techno-economic performance of a GCEC system. The model consists of the ejector and the borehole heat exchanger submodels. The first section of the results compares the ACEC system and the GCEC system during a cooling season. The seasonal...
Techno-economic optimization of biogas-fueled micro gas turbine cogeneration systems in sewage treatment plant
, Article Energy Conversion and Management ; Volume 218 , 15 August , 2020 ; Avami, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The aim of this paper is to investigate the feasibility of a combined cooling, heating, and power generation system with a micro turbine using biogas as the fuel to supply the heat and electricity demands in a real wastewater treatment plant. The plant is optimized using the system's total cost rate and the amount of the produced biogas as objective functions. The anaerobic digester is modeled using the ADM1 model. The optimization variables include digester hydraulic retention time, compressor pressure ratio, isentropic compressor efficiency, recuperator pinch time temperature, turbine isentropic efficiency, turbine input temperature, and the number of micro turbines. In the first scenario...
Fabrication of porous gelatin-chitosan microcarriers and modeling of process parameters via the RSM method
, Article International Journal of Biological Macromolecules ; Volume 88 , 2016 , Pages 288-295 ; 01418130 (ISSN) ; Mashayekhan, S ; Baniasadi, H ; Sharif University of Technology
Elsevier B.V
Abstract
Porous gelatin-chitosan microcarriers (MCs) with the size of 350 ± 50 μm were fabricated with blends of different gelatin/chitosan (G/C) weight ratio using an electrospraying technique. Response surface methodology (RSM) was used to study the quantitative influence of process parameters, including blend ratio, voltage, and syringe pump flow rate, on MCs diameter and density. In the following, MCs of the same diameter and different G/C weight ratio (1, 2, and 3) were fabricated and their porosity and biocompatibility were investigated via SEM images and MTT assay, respectively. The results showed that mesenchymal stem cells (MSCs) could attach, proliferate, and spread on fabricated porous MCs...
Beating-heart robotic surgery using bilateral impedance control: Theory and experiments
, Article Biomedical Signal Processing and Control ; Volume 45 , 2018 , Pages 256-266 ; 17468094 (ISSN) ; Salarieh, H ; Behzadipour, S ; Tavakoli, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
A bilateral impedance controller is presented to enable robot-assisted surgery of a beating heart. For this purpose, two desired impedance models are designed and realized for the master and slave robots interacting with the operator (surgeon) and the environment (heart tissue), respectively. The impedance models are designed such that (a) the slave robot complies with the oscillatory motion of the beating heart and (b) the surgeon perceives the non-oscillatory portion of the slave/heart contact force at the master robot implying arrested-heart surgery. These performance goals are achieved via appropriate adjustment of the impedance model parameters without any measurement or estimation of...