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Experimental study on the removal of Ca(II) from aqueous solution using a bulk liquid membrane with facilitated transport mechanism
, Article Chemical Engineering Research and Design ; Volume 191 , 2023 , Pages 353-363 ; 02638762 (ISSN) ; Karimi Sabet, J ; Ghotbi, C ; Sharif University of Technology
Institution of Chemical Engineers
2023
Abstract
Calcium ion is one of the scale-forming cations in water, as it can readily produce sulfate and carbonate scales. Liquid membranes eliminate the equilibrium constraints of liquid-liquid extraction by integrating extraction and stripping processes into one unit and therefore offer tremendous potential for removing various metal ions from aqueous solutions. In this study, the ability of a bulk liquid membrane (BLM) containing di-(2-ethylhexyl) phosphoric acid (D2EHPA) as a carrier to remove Ca(II) ions from aqueous solutions was explored. D2EHPA showed good efficacy and significantly facilitated transport of Ca(II) through the BLM. The transport mechanism by D2EHPA was investigated using pH...
Idle time and gelation behavior in gelcasting process of PSZ in acrylamide system
, Article Ceramic Transactions, 31 May 2009 through 5 June 2009 ; Volume 212 , JUL , 2010 , Pages 105-113 ; 10421122 (ISSN) ; 9780470876466 (ISBN) ; Faghihi Sani, M. A ; Sharif University of Technology
2010
Abstract
Gelcasting is a novel forming method in fabricating complex three dimensional ceramic parts, and has many parameters and characteristics required to be specified. Up to now, few articles have been published on determination of the idle time of gelation precisely. In this work the chemorheology of gelation in aqueous solution of acrylamide and N, N′ methylenebisacrylamide monomer, and zirconia (PSZ) suspensions of this solution was investigated. As the viscosity of gel system increases abruptly in gelation point, idle time can be determined precisely by measurement of viscosity against time. Idle time can also be determined through temperature measurement against time since the reaction of...
Experimental Study of Flow Pattern, Relative Permeability and Saturation of Three Phase Flow
, M.Sc. Thesis Sharif University of Technology ; Shad, Saeed (Supervisor)
Abstract
Today, the Oil industry, much progress has been made in terms of increasing the productivity of reservoirs. In this method, generally one or more fluids are injected into wells to help, extract more oil from the reservoir. Knowledge of the main parameters in this flow of two or three phase fluid in the reservoir is most important. If fractured reservoirs are studied, the multiphase flow are much more complex and require more information about that. Unfortunately, due to the complexity of fractured reservoirs and fluid flow within them, little research has been done on them. The studies about two or three phase flow in fractured reservoirs are classified in two groups, modeling and laboratory...
Experimental Study and Optimization of Calcium Ion Extraction Using Emulsion Liquid Membrane with Isotope Separation Perspective
, Ph.D. Dissertation Sharif University of Technology ; Ghotbi, Cyrus (Supervisor) ; Karimi Sabet, Javad (Supervisor)
Abstract
The aim of this dissertation is to investigate the extraction of calcium ions using an emulsion liquid membrane (ELM) with an isotopic perspective. Considering the importance of ion extraction as a preliminary step to isotope separation, the factors affecting the extraction of Ca(II) ions in the ELM process were investigated and optimization of the process was performed in this study. Dicyclohexano-18-crown-6 (DC18C6) was used as the carrier due to isotopic considerations. However, its extractability for calcium ions is limited. In order to address this issue, it is possible to introduce an organic acid, specifically di-(2-ethylhexyl) phosphoric acid (D2EHPA), into the membrane phase. This...
Kinetics of chemical ordering in a Ag-Pt nanoalloy particle via first-principles simulations
, Article Journal of Chemical Physics ; Volume 137, Issue 19 , 2012 ; 00219606 (ISSN) ; Taherkhani, F ; Parsafar, G ; Caro, A ; Fortunelli, A ; Sharif University of Technology
2012
Abstract
The energetics and kinetic energy barriers of vacancy/atom exchange in a 37-atom truncated octahedron Ag-Pt binary cluster in the Ag-rich range of compositions are investigated via a first-principles atomistic approach. The energy of the local minima obtained considering various distributions of a single vacancy and a few Pt atoms within the cluster and the energy barriers connecting them are evaluated using accurate density-functional calculations. The effects of the simultaneous presence of a vacancy and Pt atoms are found to be simply additive when their distances are larger than first-neighbors, whereas when they can be stabilizing at low Pt content due to the release of strain by the...
Theoretical and experimental study of cascade solar stills
, Article Solar Energy ; Volume 90 , April , 2013 , Pages 205-211 ; 0038092X (ISSN) ; Sharak, A. Z ; Moghadam, H ; Tabrizi, F. F ; Sharif University of Technology
2013
Abstract
Most part of Iran is dominated by arid and semi-arid areas due to low annual rainfall. The need for production of fresh water from brackish water is considerably high, especially in dry regions. In this study 1 month daily-based experimental data from a solar still site has been reported. The technical and operational problems of this site which finally contributed to the total cease of the site are described. Then a detailed analysis is investigated on progress of a prototype which constructed in order to solve the site's problems. The results of 1 month of experimental data of the final design showed that the last prototype could be used to solve the current problems of the site. The...
Nanomaterial-assisted pyrolysis of used lubricating oil and fuel recovery
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 ; Abdoli, M. A ; Khorasheh, F ; Nezhadbahadori, F ; Bayandori Moghaddam, A ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Used lubricating oil (ULO) is a heavy mixture of various hydrocarbons and needs to be treated before discharging. Considering ULO nature, it is more favorable to recover lighter hydrocarbon cuts from ULO, which not only improves the whole process economically, but also prevents the emission of hardly decomposable hydrocarbons into the environment. In this research, the potential of pyrolysis method for ULO recovery was studied. Furthermore, graphene nanoplatelets (GNP), γ- Fe2O3 and ZnO nanoparticles were used to improve the kinetics of the process and their impacts on the final product quality were evaluated. Based on the results, adding nanomaterials increased the tendency to produce gas...
Investigation of rotary ultrasonic vibration assisted machining of Nomex honeycomb composite structures
, Article International Journal of Advanced Manufacturing Technology ; Volume 129, Issue 11-12 , 2023 , Pages 5541-5560 ; 02683768 (ISSN) ; Jamil, M. F ; Qureshi, M. A. M ; Qaiser, A. A ; Khalid, F. A ; Maqbool, A ; Raza, S. F ; Ahmad, S ; Zhang, J ; Abbas, S. Z ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2023
Abstract
The applications of Nomex honeycomb composite (NHC) structures in aerospace, automotive and defence sectors have been significantly increasing due to their high compressive strength, hexagonal thin-walled structure, ultra-light weight and excellent thermal resistance. Specific applications include composite sandwich structures in helicopter propellers, satellite cabins, aeroplane floors, engine cowls, wings and nacelles. Accuracy of the machined surface of NHC structures is required for adhesive bonding with face-sheets. Conventional machining processes generate machining defects in terms of tearing, damaged cell walls, burr formation, delamination and poor surface quality that result in...
Design and development of an effective low-cost robotic cameraman for laparoscopic surgery: RoboLens
, Article Scientia Iranica ; Volume 18, Issue 1 B , 2011 , Pages 59-71 ; 10263098 (ISSN) ; Farahmand, F ; Meghdari, A ; Karimian, F ; Sharif University of Technology
2011
Abstract
A robotic system was designed and developed to perform the camera handling task during laparoscopic surgery. The system employs an effective low cost mechanism, with a minimum number of actuated DOFs, enabling spherical movement around a remote centre of motion positioned at the the insertion point of the laparoscopic stem. Kinematic analysis showed a high manipulability measure for the system, with the left/right movements directly governed by rotation of the first rotary actuator, and zoom and up/down movements by the simultaneous motions of the linear and second rotary actuators. A prototype of the robot was developed for practical use in an operating room environment. Hands-free operator...
A multiscale phase field method for joint segmentation-rigid registration application to motion estimation of human knee joint
, Article Biomedical Engineering - Applications, Basis and Communications ; Volume 23, Issue 6 , 2011 , Pages 445-456 ; 10162372 (ISSN) ; Esfandiarpour, F ; Shakourirad, A ; Farahmand, F ; Sharif University of Technology
2011
Abstract
Image based registration of rigid objects has been frequently addressed in the literature to obtain an object's motion parameters. In this paper, a new approach of joint segmentation-rigid registration, within the variational framework of the phase field approximation of the Mumford-Shah's functional, is proposed. The defined functional consists of two Mumford-Shah equations, extracting the discontinuity set of the reference and target images due to a rigid spatial transformation. Multiscale minimization of the proposed functional after finite element discretization provided a sub-pixel, robust algorithm for edge extraction as well as edge based rigid registration. The implementation...
Extraction and quantitative determination of ascorbic acid during different maturity stages of Rosa canina L. fruit
, Article Journal of Food Composition and Analysis ; Volume 21, Issue 4 , 2008 , Pages 300-305 ; 08891575 (ISSN) ; Khalilian, F ; Kiaie, F. M ; Rahimi, A ; Arabanian, A ; Chalavi, S ; Sharif University of Technology
2008
Abstract
Dog rose (Rosa canina L.) fruit in different stages of proposed was used as a source of ascorbic acid. Two sample preparation methods for extracting ascorbic acid in dog rose fruit were evaluated. These methods used high performance of liquid chromatography (HPLC) for detecting of ascorbic acid, but differed in the preparation of sample (freezing and mild-temperature-drying procedure). Under optimized conditions, the freezing procedure demonstrated better results. The method was used to compare the amount of ascorbic acid in fully ripe, half-ripe and unripe dog rose samples. The results show that dog rose has the highest amount of ascorbic acid in its fully ripe maturity stage. In addition,...
Effect of recycle gas composition of the performance of Fischer-Tropsch catalyst
, Article Petroleum Science and Technology ; Volume 28, Issue 5 , 2010 , Pages 458-468 ; 10916466 (ISSN) ; Khorashe, F ; Safekordi, A. A ; Tavassoli, A ; Sharif University of Technology
2010
Abstract
In this study, the influence of CO2 and CH4 on the performance and selectivity of Co-Ru/Al2O3 catalyst is investigated by injection of these gases (0-20 vol.% of feed) to the feed stream. The effect of temperature and feed flow rate are also inspected. The results show that low amounts of CO2 in the feed stream do not change the catalyst activity, but increasing the amount of CO2 (more than 10 vol.%), causes the CO conversion to decrease and the selectivity of heavy components to increase. Methane acts as an inert gas and does not affect the catalyst performance. Increasing feed flow rate has a negative effect on both CO conversion and heavy component selectivity. By raising the temperature,...
Microstructure and texture development during friction stir processing of Al–Mg alloy sheets with TiO2 nanoparticles [electronic resource]
, Article Materials Science and Engineering: A ; 27 May 2014, Volume 605, Pages 108–118 ; Simchi, A. (Abdolreza) ; Kokabi, A. H ; Nosko, M ; Simancik, F ; Svec, P ; Sharif University of Technology
Abstract
Aluminum matrix nanocomposites were fabricated by friction stir processing of Al–Mg alloy sheets with pre-placed TiO2 nanoparticles at a concentration of 2 to 6 vol%. Microstructural studies showed that solid state reactions between the metal matrix and TiO2 particles caused in situ formation of MgO and Al3Ti nanophases with an average size ~50 nm. These nanophases were homogenously distributed in an ultra-fine grain structure (0.2–2 µm) of the base metal. The results of pole figures evaluation obtained by electron back scattered diffraction studies revealed that the random orientation of initial annealed sheet was changed to components near to shear and silver texture in the friction stir...
Evaluation of operational parameters role on the emission of fumes
, Article Industrial Health ; Volume 56, Issue 3 , 2018 , Pages 198-206 ; 00198366 (ISSN) ; Kokabi, A. H ; Dehghan, S. F ; Mehri, A ; Azam, K ; Golbabaei, F ; Sharif University of Technology
National Institute of Industrial Health
2018
Abstract
Electric arc welding is a routine operation in the construction of metallic structures, but the fumes generated during the welding process can threaten the health of welders. Fumes are undesirable products of the majority of welding operations and may have various detrimental effects on health. The purpose of this study was to investigate the effect of operational parameters of the shielded metal arc welding SMAW process on the emission of fumes. A dust monitor was used to measure the number and mass concentration of fumes generated by SMAW. Measurements were made at the distances of 23 cm hood inlet and 41 cm welder’s breathing zone from the weld point, with different values assigned to...
CuO and ZnO co-anchored on g-C3N4 nanosheets as an affordable double Z-scheme nanocomposite for photocatalytic decontamination of amoxicillin
, Article Applied Catalysis B: Environmental ; Volume 285 , 2021 ; 09263373 (ISSN) ; Hasanvandian, F ; Isari, A. A ; Hayati, F ; Kakavandi, B ; Setayesh, S. R ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In this study, both CuO nanoparticles and ZnO nanorods were anchored on thermally-exfoliated g-C3N4 nanosheets (denoted as CZ@T-GCN) via isoelectric point-mediated annealing process as a novel nano-photocatalyst towards degradation of amoxicillin (AMOX). The features of prepared materials were characterized using BET, UV–vis DRS, XRD, FT-IR, XPS, FE-SEM, TEM, EIS and transient photocurrent techniques. These analyses demonstrated the successful formation of heterojunctions between components of CZ@T-GCN nanocomposite, which reflected in significantly increased electron-hole separation and enhanced degradation of AMOX as compared with pure substances. The investigation of influential operative...
Patellofemoral Joint Biomechanics
, Article Patellofemoral Disorders: Diagnosis and Treatment ; 2005 , Pages 37-53 ; 9780470011164 (ISBN); 0470850116 (ISBN); 9780470850114 (ISBN) ; Bull, A. M. J ; Farahmand, F ; Senavongse, W ; Shih, Y. F ; Sharif University of Technology
Wiley Blackwell
2005
Catalytic effect of copper oxide on H2S sensing properties of nanostructured WO3
, Article Sensor Letters ; Volume 11, Issue 11 , 2013 , Pages 2015-2020 ; 1546198X (ISSN) ; Razi, F ; Rahimi, F ; Zad, A. I ; Sharif University of Technology
American Scientific Publishers
2013
Abstract
Cuprous oxide powder was added to WO3 sol as a catalyst and the composite sol was deposited on alumina substrates by spin coating process and annealing at 500 °C for 1 hour. Sensing properties of the pure and doped tungsten oxide samples to H2S gas were analyzed. WO 3-Cu2O (1%) samples showed good sensitivity towards 250 ppb of the gas at 100 °C and 1 ppm at room temperature (25 °C). Crystal structure, morphology and chemical composition of the sample were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDAX) analyses and X-ray photoelectron spectroscopy (XPS). Based on these data, possible reaction mechanisms of hydrogen sulfide over WO...
Frozen leg operation of a three-phase dual active bridge DC/DC converter at light loads
, Article Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC ; Volume 2018-March , 18 April , 2018 , Pages 3385-3391 ; 9781538611807 (ISBN) ; Blaabjerg, F ; Yazdani, F ; Bahman, A. S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
A three-phase dual active bridge (DAB) converter is designed and constructed as the DC/DC stage of a 50 kW fast charger station. Recently introduced 300A SiC power modules and drivers are utilized in the converter to obtain a high efficiency. Each module has two interconnected switches with anti-parallel diodes resembling a converter leg. It is observed that the driver halts the module operation as a result of protective actions such as over-current, gate under-voltage, or gate overvoltage. In such case the module operates as a leg with two diodes until an external hardware signal resets the driver. The aim of this paper is to provide analysis, simulation and experiments for a three-phase...
Inhibitory effects of functionalized indium doped ZnO nanoparticles on algal growth for preservation of adobe mud and earthen-made artworks under humid conditions
, Article International Biodeterioration and Biodegradation ; Volume 127 , Febraury , 2018 , Pages 209-216 ; 09648305 (ISSN) ; Mallakin, A ; Malekmohammady, F ; Khosravi Nejad, F ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this article, indium doped ZnO nanoparticles (alloy nanoparticles) were investigated as inhibitors against algae growth on adobe mud and earthen artworks for surface preservation from destruction caused by micro-organisms under humid conditions, through surface modification and activation run off. Nanoparticles (NPs) were fabricated by physical vapor deposition (PVD) growth mechanism. The fabricated NPs were approximately 20 nm in size. The Chlorella vulgaris and Scenedesmus quadricauda were tested by application of indium doped ZnO nanoparticles (In/ZnO NPs) as inhibitors. As concentrations of NPs increased, the negative impacts of NPs on the algal growth were enhanced and physical...
Dynamic VNF placement, resource allocation and traffic routing in 5G
, Article Computer Networks ; Volume 188 , April , 2021 ; 13891286 (ISSN) ; Chiasserini, C. F ; Malandrino, F ; Movaghar, A ; Sharif University of Technology
Elsevier B. V
2021
Abstract
5G networks are going to support a variety of vertical services, with a diverse set of key performance indicators (KPIs), by using enabling technologies such as software-defined networking and network function virtualization. It is the responsibility of the network operator to efficiently allocate the available resources to the service requests in such a way to honor KPI requirements, while accounting for the limited quantity of available resources and their cost. A critical challenge is that requests may be highly varying over time, requiring a solution that accounts for their dynamic generation and termination. With this motivation, we seek to make joint decisions for request admission,...