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Comparison and validation of plug and boundary layer flow models of monolithic reactors: Catalytic partial oxidation of methane on Rh coated monoliths
, Article International Journal of Chemical Reactor Engineering ; Volume 6 , 2008 ; 15426580 (ISSN) ; Safekordi, A ; Farhadpour, F. A ; Sharif University of Technology
Walter de Gruyter GmbH
2008
Abstract
Catalytic partial oxidation of methane in short residence time rhodium coated monolithic reactors offers an attractive route for syngas production. The plug flow and boundary layer flow approximations are considered as computationally efficient substitutes for the full Navier-Stokes model of the reactor while including detailed heterogeneous and homogeneous chemistry. The one dimensional plug flow model has trivial computational demands but only a limited range of application. The boundary layer model provides an excellent, computationally manageable substitute for the full Navier-Stokes model over a wide range of operating conditions. Using the 38-step elementary surface reaction mechanism...
Sending mobile software activation code by SMS using steganography
, Article 3rd International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIHMSP 2007, Kaohsiung, 26 November 2007 through 28 November 2007 ; Volume 1 , February , 2007 , Pages 554-557 ; 0769529941 (ISBN); 9780769529943 (ISBN) ; Shirali Shahreza, M ; Sharif University of Technology
2007
Abstract
Now we are able to offer numerous softwares for mobile phones after the advances in mobile phone industry. Most of these softwares should be bought in order that we can use them. Some of these softwares are sharewares and after buying them you have to insert an activation code given by the manufacturing company based on your mobile IMEI code in order to activate the software. In this paper a new method is introduced for sending the mobile software activation code by SMS (Short Message Service). In this method the activation code is hidden in an SMS picture message by steganography method and sent to the user. The software extracting the activation code from the picture and compare it with...
A new scheme for a mechanical load position control driven by a permanent magnet DC motor and a nonzero backlash gearbox
, Article International Symposium on Industrial Electronics 2006, ISIE 2006, Montreal, QC, 9 July 2006 through 13 July 2006 ; Volume 3 , 2006 , Pages 2052-2057 ; 1424404975 (ISBN); 9781424404971 (ISBN) ; Barati, F ; Sharif University of Technology
2006
Abstract
In this paper, a new scheme for position control of a mechanical load driven by a permanent magnet DC motor and a gearbox is presented. The gearbox is assumed to have some amount of backlash. The paper derives a model for the backlash nonlinear behavior. It then proposes a new control structure composed of feedback and feed forward control systems. The feedback control system is designed based on zero backlash. The feed forward part is employed to minimize the backlash effects. The new method is evaluated via simulations in MATLAB/SEVIULINK environment. Simulations results are provided to show the response of the proposed technique to various input references. © 2006 IEEE
Preventing mobile software cracking using CAPTCHA
, Article 2006 Innovations in Information Technology, IIT, Dubai, 19 November 2006 through 21 November 2006 ; 2006 ; 1424406749 (ISBN); 9781424406746 (ISBN) ; Shirali Shahreza, S ; Sharif University of Technology
2006
Abstract
Now we are able to offer numerous softwares for mobile phones after the advances in mobile phone industry. Most of these softwares should be bought in order that we can use them. Some of these softwares are sharewares and after buying them you have to insert a serial number given by the manufacturing company in order to activate the software. But the crackers reproduce them illegally by cracking the software. One of the tactics used by crackers for finding the serial number of the softwares is brute force attacks. In this paper a method based on CAPTCHA (Completely Automated Public Turing Test to tell Computer and Humans Apart) is proposed for solving this problem. In this method while...
Vibration control and manufacturing of intelligibly designed axially functionally graded cantilevered macro/micro-tubes
, Article 13th IFAC Workshop on Intelligent Manufacturing Systems, IMS 2019, 12 August 2019 through 14 August 2019 ; Volume 52, Issue 10 , 2019 , Pages 382-387 ; 24058963 (ISSN) ; Ebrahimi Mamaghani, A ; Ahmadian, M. T ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In the last decade, extensive attention is devoted to intelligibly designed materials of macro/micro-structures containing the fluid flow. In this study, intelligent control and vibrational stability of cantilevered fluid conveying macro/micro-tubes utilizing axially functionally graded (AFG) materials are considered. The governing equation of motion of the system is derived based on modified couple stress theory and then is discretized using Galerkin method. A detailed investigation is carried out to elaborate the influence of various parameters such as material properties, axial compressive load, and Pasternak foundation on the dynamical behavior of the system, all of which are influential...
The influence of lanthanide on NiO-MgO-SiO2 catalysts for syngas production via propane steam reforming
, Article Molecular Catalysis ; Volume 499 , 2021 ; 24688231 (ISSN) ; Rezaei, M ; Kazemeini, M ; Farhadi, F ; Keshavarz, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In this study, 15 wt. % NiO-MgO-SiO2 catalysts modified by La2O3 promoter were prepared through a co-precipitation route and employed for syngas production via propane steam reforming. Various techniques including X-Ray diffraction, BET, TPR, CO2-TPD, CO-chemisorption, TPO, and Scanning electron microscopy were utilized to characterize the final samples. The results indicated that the incorporation of La2O3 enhanced the metal-support interaction providing less reducible Ni species. In comparison with the La-free catalyst, the promoted ones possessed higher metal dispersion and smaller Ni particles. Nonetheless, excessive amounts of La covering the active sites negatively decreased the Ni...
A novel low-temperature growth of uniform CuInS2 thin films and their application in selenization/sulfurization-free CuInS2 solar cells
, Article Materials Today Communications ; Volume 26 , 2021 ; 23524928 (ISSN) ; Parvazian, E ; Alamgir Tehrani, N ; Taghavinia, N ; Samadpour, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In terms of manufacturability, there is a high tendency to deposit light-absorbing CuInS2 films by solution processing methods like ink-based depositions. In particular, for nanoparticle inks, the synthesis of highly dispersed and stable inks, with uniformity in the deposition process, is a serious challenge. Here, we demonstrate a novel two-step low-temperature CuInS2 film deposition method in which the In2S3 is deposited first. It then partially is converted into CuInS2 through the infiltration of Cu+ ions in the In2S3 layer in a dip-coating process. The resulting films are highly uniform, with diffraction peaks indicating the formation of pure CuInS2 phase. The proper stoichiometry of...
Developing a new superhydrophilic and superoleophobic poly(4-(1-vinyl-1H-imidazol-3-ium-3-yl) butane-1-sulfonate): vinyl imidazole@Perfluorooctanoic acid@SiO2 coated stainless steel mesh for highly efficient, stable, and durable oil/water separation
, Article Journal of Coatings Technology and Research ; Volume 18, Issue 2 , 2021 , Pages 511-521 ; 15470091 (ISSN) ; Siavash Moakhar, R ; Amirpoor, S ; Azad, M ; Dolati, A ; Sharif University of Technology
Springer
2021
Abstract
The design and development of efficient approaches for water–oil separation have had widespread interest. Most previously introduced techniques and materials used for development of the successful separation of oily wastewater could not answer all the desired demands, such as being efficient and environmentally and economically friendly. Therefore, in seeking a novel method capable of answering these expectations, surfaces with special wettability were introduced. A novel, reusable, and recyclable superhydrophilic and superoleophobic poly(Vsim-Vim)@PFOA@SiO2 nanocomposite-coated stainless steel mesh was synthesized through a facile preparation process. Since the most important factors of...
Multi-objective optimization of job shops with automated guided vehicles: A non-dominated sorting cuckoo search algorithm
, Article Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability ; Volume 235, Issue 2 , 2021 , Pages 306-328 ; 1748006X (ISSN) ; Akhavan Niaki, S. T ; Niknamfar, A. H ; Hassanlu, M. G ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
The reliability of machinery and automated guided vehicle has been one of the most important challenges to enhance production efficiency in several manufacturing systems. Reliability improvement would result in a simultaneous reduction of both production times and transportation costs of the materials, especially in automated guided vehicles. This article aims to conduct a practical multi-objective reliability optimization model for both automated guided vehicles and the machinery involved in a job-shop manufacturing system, where different machines and the storage area through some parallel automated guided vehicles handle materials, parts, and other production needs. While similar machines...
Sustainable ammonia production from steam reforming of biomass-derived glycerol in a heat-integrated intensified process: Modeling and feasibility study
, Article Journal of Cleaner Production ; Volume 324 , 2021 ; 09596526 (ISSN) ; Lotfi Varnoosfaderani, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Currently, ammonia, as a clean and sustainable energy carrier, is intensively synthesized from its elements during the Haber-Bosch technology. This process requires a large amount of energy and emits numerous amounts of carbon dioxide, because hydrogen is dominantly produced from fossil fuels through reforming processes. Biomass-derived glycerol steam reforming is an attractive alternative to traditional reforming for reducing the dependence on hydrocarbon resources and mitigating climate change. This research aims to intensify a heat-integrated process for the co-production of ammonia and syngas from glycerol valorization. In this process, glycerol reforming continuously provides hydrogen...
An integrated process configuration of solid oxide fuel/electrolyzer cells (SOFC-SOEC) and solar organic Rankine cycle (ORC) for cogeneration applications
, Article International Journal of Energy Research ; Volume 45, Issue 7 , 2021 , Pages 11018-11040 ; 0363907X (ISSN) ; Karimian Bahnamiri, F ; Mehrpooya, M ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
This research work presents a novel integrated structure for the cogeneration of electricity and renewable syngas. The base structure of the process is developed by solid oxide cells in which electricity is generated by the natural gas-fueled fuel cell unit, and renewable syngas is produced by the electrolyzer cell unit. Direct integration between fuel cell and electrolyzer cell units is established for optimal use of fuel cell off-gases. To improve system's sustainability, a solar power cycle, including solar collectors coupled with an organic Rankine cycle (ORC), is designed to provide renewable electricity for steam and CO2 co-electrolysis operation. 1D mathematical approaches are...
Diatoms with invaluable applications in nanotechnology, biotechnology, and biomedicine: Recent advances
, Article ACS Biomaterials Science and Engineering ; Volume 7, Issue 7 , 2021 , Pages 3053-3068 ; 23739878 (ISSN) ; Khatami, M ; Jamalipour Soufi, G ; Fatahi, Y ; Iravani, S ; Varma, R. S ; Sharif University of Technology
American Chemical Society
2021
Abstract
Diatoms are unicellular microalga found in soil and almost every aquatic environment (marine and fresh water). Biogenic silica and diatoms are attractive for biotechnological and industrial applications, especially in the field of biomedicine, industrial/synthetic manufacturing processes, and biomedical/pharmaceutical sciences. Deposition of silica by diatoms allows them to create micro- or nanoscale structures which may be utilized in nanomedicine and especially in drug/gene delivery. Diatoms with their unique architectures, good thermal stability, suitable surface area, simple chemical functionalization/modification procedures, ease of genetic manipulations, optical/photonic...
A feasibility study of solar-powered reverse osmosis processes
, Article Desalination ; Volume 500 , 2021 ; 00119164 (ISSN) ; Shirvani, H ; Alamolhoda, A. A ; Farhadi, F ; Karimi, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The use of solar-powered reverse osmosis desalination systems is a sustainable and environmentally friendly solution in the desalination industry. However, there are some substantial technical and economic challenges due to the intermittency and fluctuation of solar energy. Recent technological improvement and feed-in tariff policies enable these systems to be competitive with conventional grid-connected reverse osmosis systems. In this paper, a feasibility study of the integration of solar panels with the grid to power small-scale reverse osmosis systems (namely up to 2000 m3/day) is conducted in Iran, as a country with a low price of electricity. For this purpose, a city located on the...
An integrated analysis of productivity, hole quality and cost estimation of single-pulse laser drilling process
, Article Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture ; Volume 235, Issue 14 , 2021 , Pages 2273-2287 ; 09544054 (ISSN) ; Shehab, E ; Salonitis, K ; Suder, W ; Niamat, M ; Jamil, M ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
Laser drilling is a well-established manufacturing process utilised to produce holes in various aeroengine components. This research presents an experimental investigation on the effects of laser drilling process parameters on productivity (material removal rate), hole quality (hole taper) and drilling cost. Single-pulse drilling was employed to drill a thin-walled Inconel 718 superalloy plate of 1 mm thickness using pulsed Nd:YAG laser. The experiments were designed using Box-Behnken statistical approach to investigate the impacts of pulse energy, pulse duration, gas pressure and gas flow rate on the selected responses. Multi-objective optimisation was performed using response surface...
A state-of-the-art review of the fabrication and characteristics of titanium and its alloys for biomedical applications
, Article Bio-Design and Manufacturing ; 2021 ; 20965524 (ISSN) ; Rezvani Ghomi, E ; Alipour, S ; Ramakrishna, S ; Liana Sukiman, N ; Sharif University of Technology
Springer
2021
Abstract
Abstract: Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950s. Due to the excellent mechanical tribological properties, corrosion resistance, biocompatibility, and antibacterial properties of titanium, it is getting much attention as a biomaterial for implants. Furthermore, titanium promotes osseointegration without any additional adhesives by physically bonding with the living bone at the implant site. These properties are crucial for producing high-strength metallic alloys for biomedical applications. Titanium alloys are manufactured into the three types of α, β, and α + β. The scientific and clinical...
Coefficient of performance of mono-and multi-crystalline silicon photovoltaic panels
, Article Solar World Congress 2005: Bringing Water to the World, Including 34th ASES Annual Conference and 30th National Passive Solar Conference, Orlando, FL, 6 August 2005 through 12 August 2005 ; Volume 2 , 2005 , Pages 1045-1050 ; 9781622762637 (ISBN) ; Zamzamian, K ; Sharif University of Technology
2005
Abstract
The coefficient of performance (COP) of a photovoltaic panel or module is defined as the ratio of the total electrical energy produced by the panel during its life to the total energy spent for its manufacture. All processes involved for the manufacture of photovoltaic panels were considered and the energy spent per unit mass of the final product during each process was determined. The total electrical energy spent for the manufacture of a photovoltaic module of 1×0.5 m dimensions, employing 340 micron wafers, with the net wafer area of 0.36 m2, was then determined. Monocrystalline and multicrystalline silicon cells were employed. It was found that for the manufacture of the PV module...
Evolution of quantum electronic features with the size of silicon nanoparticles embedded in a sio2 layer obtained by low energy ion implantation
, Article 11th International Autumn Meeting on Gettering and Defect Engineering in Semiconductor Technology, GADEST 2005, 25 September 2005 through 30 September 2005 ; Volume 108-109 , 2005 , Pages 71-76 ; 10120394 (ISSN); 9783908451136 (ISBN) ; Shalchian, M ; Benassayag, G ; Coffin, H ; Bonafos, C ; Dumas, C ; Atarodi, S. M ; Claverie, A ; Pichaud B ; Claverie A ; Alquier D ; Richter H ; Kittler M ; Richter H ; Kittler M ; Sharif University of Technology
Trans Tech Publications Ltd
2005
Abstract
In this paper, we have studied the evolution of quantum electronic features with the size of silicon nanoparticles embedded in an ultra-thin SiO2 layer. These nanoparticles were synthesized by ultralow energy (1 KeV) ion implantation and annealing. Their size was modified using the effect of annealing under slightly oxidizing ambient (N2+O2). Material characterization techniques including transmission electron microscopy (TEM) Fresnel imaging and spatially resolved electron energy loss spectroscopy (EELS) have been used to evaluate the effects of oxidation on structural characteristics of nanocrystal layer. Electrical transport characteristics have been measured on few (less than two...
Performance analysis of an outer rotor variable reluctance resolver
, Article IEEE Sensors Journal ; Volume 22, Issue 18 , 2022 , Pages 17761-17768 ; 1530437X (ISSN) ; Tootoonchian, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Variable reluctance resolver (VR-Resolver) is a robust electromagnetic sensor that provides position information for closed-loop control systems of permanent magnet synchronous motors (PMSMs). For specific motion control applications, an outer rotor structure is presented for the VR-Resolver in this article with a nonoverlapping tooth-coil windings configuration to simplify the manufacturing process. The study on the structure of the proposed position sensor is carried out, followed by the description of the working principle. The presented outer rotor VR-Resolver is simulated and its performance is investigated in detail with the aid of transient finite-element analysis (TFEA). Sensitivity...
Developing a novel technique for the fabrication of PLA-graphite composite filaments using FDM 3D printing process
, Article Ceramics International ; Volume 48, Issue 21 , 2022 , Pages 31850-31858 ; 02728842 (ISSN) ; Sayedain, S. S ; Tavangarifard, M ; Alizadeh, R ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Developing a uniform polymer-based composite filament is a critical factor for a successful 3D printing process. In this regard, a novel technique for the fabrication of PLA-graphite filament with the potential to be applied to other PLA-based composite filaments was proposed and compared to the solvent casting method. This modified mixing technique involves partial dissolution of the PLA pellets surface by dichloromethane (DCM), which creates a sticky surface for the strong adhesion of reinforcement powders. The manufactured composite filament by this method exhibited excellent structural features, while the solvent casting method yielded a heterogeneous filament with a non-uniform diameter...
Effects of plate contouring quality on the biomechanical performance of high tibial osteotomy fixation: A parametric finite element study
, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 236, Issue 3 , 2022 , Pages 356-366 ; 09544119 (ISSN) ; Farahmand, F ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
Locking plates have threaded holes, in which threaded-head screws are affixed. Hence, they do not need to be in intimate contact with underlying bone to provide fixation. There are, however, reports that a large distance between the plate and the bone might cause clinical complications such as delayed union or nonunion, screw pull out, and screw and plate breakage. Considering the diversity in the capabilities and costs of different plate customization techniques, the purpose of this study was to investigate the effect of the plate contouring quality on the biomechanical performance of high tibial osteotomy (HTO) fixation. A finite element model of proximal tibia was developed in Abaqus,...