Loading...
Search for:
tabei--s--m--a
0.154 seconds
Total 27944 records
Intermittency of height fluctuations in stationary state of the Kardar-Parisi-Zhang equation with infinitesimal surface tension in 1+1 dimensions
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 70, Issue 3 1 , 2004 , Pages 031101-1-0311011-3 ; 15393755 (ISSN) ; Bahraminasab, A ; Masoudi, A. A ; Mousavi, S. S ; Tabar, M. R. R ; Sharif University of Technology
2004
Abstract
Intermittency of height fluctuations in stationary state of the Kardar-Parisi-Zhang (KPZ) equation with infinitesimal surface tension in 1+1 dimensions was discussed. Stochastic differential equations were used for the study. It was found that the probability density function [in 1+1] is independent of the coefficient of the linear term. When the random force with smooth spatial correlation was considered, the problem changed to a more complicated one
Intermittency of height fluctuations in stationary state of the Kardar-Parisi-Zhang equationwith infinitesimal surface tension in [Formula presented] dimensions
, Article Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics ; Volume 70, Issue 3 , 2004 , Pages 13- ; 1063651X (ISSN) ; Bahraminasab, A ; Masoudi, A. A ; Mousavi, S. S ; Reza Rahimi Tabar, M ; Sharif University of Technology
2004
Abstract
The Kardar-Parisi-Zhang (KPZ) equation with infinitesimal surface tension, dynamically develops sharply connected valley structures within which the height derivative is not continuous. We discuss the intermittency issue in the problem of stationary state forced KPZ equation in [Formula presented] dimensions. It is proved that the moments of height increments [Formula presented] behave as [Formula presented] with [Formula presented] for length scales [Formula presented]. The length scale [Formula presented] is the characteristic length of the forcing term. We have checked the analytical results by direct numerical simulation. © 2004 The American Physical Society
Synthesis of PZT Nanotubes by Sol-gel Method Aided by Carbon Nanotubes
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
In this project, synthesis of sol-gel derived Pb(Zr0.52Ti0.48)O3 nanotubes in the form of PZT-CNT hybrid, was accomplished by using multi-walled carbon nanotubes as sacrificial template. Simultaneous thermal analyses proved that the as-derived amorphous material crystallized at a significantly low temperature by a considerably low activation energy. X-ray diffraction and selected area electron diffraction patterns showed that the final crystal structure is tetragonal perovskite. Raman spectroscopy results proved that significant changes happened at the surface of carbon nanotubes which are believed to be due to coating. Electron images supported the deposition of a coating on the surfaces of...
Conventional and metaheuristic optimization algorithms for solving short term hydrothermal scheduling problem: a review
, Article IEEE Access ; Volume 9 , 2021 , Pages 25993-26025 ; 21693536 (ISSN) ; Liaquat, S ; Kashif, S. A. R ; Rasool, A ; Khizer, M ; Iqbal, M. A ; Baig, M. A ; Padmanaban, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Short term hydrothermal scheduling (STHTS) is a non-linear, multi-modal and very complex constrained optimization problem which has been solved using several conventional and modern metaheuristic optimization algorithms. A number of research articles have been published addressing STHTS using different techniques. This article presents a comprehensive review of research published for solving the STHTS problem in the last four decades. © 2013 IEEE
Implementation of APSO and improved APSO on Non-cascaded and cascaded short term hydrothermal scheduling
, Article IEEE Access ; Volume 9 , 2021 , Pages 77784-77797 ; 21693536 (ISSN) ; Kashif, S. A. R ; Liaquat, S ; Rasool, A ; Padmanaban, S ; Iqbal, M. A ; Baig, M. A ; Khan, B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Short-term hydrothermal scheduling (STHTS) is a highly non-linear, multi-model, non-convex, and multi-dimensional optimization problem that has been worked upon for about 5 decades. Many research articles have been published in solving different test cases of STHTS problem, while establishing the superiority of one type of optimization algorithm over the type, in finding the near global best solution of these complex problems. This paper presents the implementation of an improved version of a variant of the Particle Swarm Optimization algorithm (PSO), known as Accelerated Particle Swarm Optimization (APSO) on three benchmark test cases of STHTS problems. The adaptive and variable nature of...
Fast spectral solutions of the double-gyre problem in a turbulent flow regime
, Article Applied Mathematical Modelling ; Volume 66 , 2019 , Pages 745-767 ; 0307904X (ISSN) ; Karabasov, S. A ; Jalali, M. A ; Sadati, S. M. H ; Sharif University of Technology
Elsevier Inc
2019
Abstract
Several semi-analytical models are considered for a double-gyre problem in a turbulent flow regime for which a reference fully numerical eddy-resolving solution is obtained. The semi-analytical models correspond to solving the depth-averaged Navier–Stokes equations using the spectral Galerkin approach. The robustness of the linear and Smagorinsky eddy-viscosity models for turbulent diffusion approximation is investigated. To capture essential properties of the double-gyre configuration, such as the integral kinetic energy, the integral angular momentum, and the jet mean-flow distribution, an improved semi-analytical model is suggested that is inspired by the idea of scale decomposition...
Effect of pesticides on erythrocytes of indigenous fish Labeo rohita
, Article Journal of King Saud University - Science ; Volume 33, Issue 7 , 2021 ; 10183647 (ISSN) ; Nadeem, A ; Maalik, S ; Mushtaq, S ; Iqbal, N ; Khan, A. K ; Shabbir, A ; Imran, M ; Niaz, S ; Yasin, M ; Qayyum, M. A ; Ahmad, B ; Skalicky, M ; Alharbi, S. A ; Alfarraj, S ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Single cell gel electrophoresis was used to observe the effect of bifenthrin and chlorpyrifos on Labeo rohita. The present work was planned to study the genotoxic effect of pesticide mixture on the major indian carp, L. rohita at sub-lethal concentration 33% LC50. First of all, 96-hr LC50 was determined for L. rohita, then fish was given sub-lethal environment for 70 days. Erythrocytes from blood were taken after each fortnight for the assessment of time dependent DNA damage (% damage), aggregate tail length of comets and genomic destruction. There was increase in damage up to 56 days and after that a slight decrease was observed in next fourteen days. After statistical analysis, it was...
Preparations and characterizations of Ca doped Ni–Mg–Mn nanocrystalline ferrites for switching field high-frequency applications
, Article Ceramics International ; Volume 48, Issue 3 , 2022 , Pages 3833-3840 ; 02728842 (ISSN) ; Nazir, M. S ; Khan, M. A ; Ullah, S ; Assiri, M. A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Ca-doped Ni–Mg–Mn spinel ferrites with compositions of Ni0·5Mg0·3Mn0.2CaxFe2-xO4 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared via sol-gel auto-ignition technique. TGA/DTA, FTIR, XRD, FESEM, and VSM were employed to evaluate the thermal, spectral, structural, morphological, and magnetic features of Ca-doped Ni–Mg–Mn spinel ferrites. TGA/DTA curves show the weight loss in the sample. This weight loss was attributed to the oxidation and decomposition of the sample contents at a temperature of 500 °C. XRD reveals a single-phase structure of the Ni–Mg–Mn nano ferrites. A single-phase orthorhombic structure was confirmed for Ca-doped Ni–Mg–Mn ferrites. Structural parameters such as lattice...
On the Formation of TiO2 Nanoparticles Via Submerged Arc Discharge Technique: Synthesis, Characterization and Photocatalytic Properties
, Article Journal of Cluster Science ; Volume 21, Issue 4 , 2010 , Pages 753-766 ; 10407278 (ISSN) ; Kavianipour, M ; Aghigh, S. M ; Ahmadi Afshar, S. A ; Saviz, S ; Iraji Zad, A ; Sharif University of Technology
2010
Abstract
We report a simple and inexpensive synthesis route of TiO2 nanoparticles using electrical arc discharge between titanium electrodes in oxygen bubbled deionized (DI) water followed by heat treatment. The resulting nanoparticles were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD patterns demonstrate formation of TiO2 phase in oxygen bubbled water after heat treatment and dominance of rutile to anatase phase. The size and morphology of TiO2 nanoparticles were studied using different arc currents as a crucial parameter in properties of final...
Adsorption and oxidation study on arsenite removal from aqueous solutions by polyaniline/polyvinyl alcohol composite
, Article Journal of Water Process Engineering ; Volume 14 , 2016 , Pages 101-107 ; 22147144 (ISSN) ; Nakhli, S. A. A ; Aghajani, M ; Rostami, M. H ; Borghei, S. M ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In this study, the Polyaniline/Polyvinyl Alcohol (PANi/PVA) composite was examined for arsenite (As(III)) removal from aqueous solution. The effect of several parameters including PVA concetration (0–5 g/L), pH (1–13), adsorbent dosage (0.5–6 g/L), contact time (0–120 min), initial As(III) concentration (0.5–100 mg/L), and As(III) oxidation were evaluated on the adsorption efficiency. The results indicated that PVA has an effective role in increasing adsorptive capacity of PANi, by changing its morphology and extending its active surface sites. The adsorption process was pH dependent and As(III) removal consistently improved by increasing solution pH. Adsorption reached equilibrium within...
Impact of void ratio and state parameters on the small strain shear modulus of unsaturated soils
, Article 15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability ; 2015 , Pages 241-246 ; Gheibi, A ; Rahimi, M ; McCartney, J. S ; Haeri, S. M
2015
Abstract
The unsaturated small strain shear modulus, Gmax, is a key reference value in predicting relationships between dynamic shear modulus and shear strain amplitude and is thus a key quantity to properly model the behavior of dynamically-loaded geotechnical systems such as pavements, rail beds, and machine foundations. From the interpretation of the experimental Gmax results for unsaturated soils, different definitions of trends between Gmax and the stress state of the unsaturated soils and material properties are proposed. However, in most of trends, the relationship between the stress state and void ratio is considered and the effect of void ratio on the unsaturated small strain shear modulus...
Partly semiconductor covered vane fast magnetron
, Article IEEE Transactions on Plasma Science ; Volume 50, Issue 5 , 2022 , Pages 1179-1187 ; 00933813 (ISSN) ; Hashemi, S. M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Alterations in the structure of a magnetron, e.g., the A6 relativistic magnetron, are proposed, which considerably increase the device's build-up speed. We cover the magnetron vane surfaces with semiconductor layers of nonzero electric conductivity, with an exact geometrical design. Semiconductor layers with considerable mechanical strength also provide excellent shielding for the vanes against the high-energy relativistic electrons' bombardment. The novel structure introduces several new free parameters to the magnetron design procedure and considerably increases the design flexibility. A multistage exact optimization procedure, performed by extensive computer simulations, shows that...
Determinants of career success: A case study of male teachers in secondary schools
, Article Estudios de Economia Aplicada ; Volume 39, Issue 4 , 2021 ; 11333197 (ISSN) ; Ramli, H. S ; Razak, M. H. A ; Abdullah, M. S ; Masum, A ; Sharif University of Technology
Ascociacion Internacional de Economia Aplicada
2021
Abstract
Malaysian secondary schools are facing a shortage of male teachers. Almost 70% of the teaching profession is dominated by female teachers. There is an obvious gap in the reason why teaching is not preferred by the male gender. This study intends to find the determinants of career success among male teachers with the hope of revealing the career success factors that are associated with male teachers. A survey was done among 140 male teachers in secondary schools in the state of Malacca, Malaysia. Results showed that 4out of 5 of the determinants factors are significantly explaining career success among the teachers (Emotional Intelligence, Person-Job-Fit, Career Adaptability & Work-Life...
Partially hydrolyzed crosslinked alginate-graft-polymethacrylamide as a novel biopolymer-based superabsorbent hydrogel having pH-responsive Properties [electronic resource]
, Article Macromolecular Research ; January 2005, Volume 13, Issue 1, pp 45-53 ; Aminfazl, M. S ; Hosseinzadeh, H
Abstract
In this study, a series of highly swelling hydrogels based on sodium alginate (NaAlg) and polymethacrylamide (PMAM) was prepared through free radical polymerization. The graft copolymerization reaction was performed in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator andN,N′-methylenebisacrylamide (MBA) as a crosslinker. The crosslinked graft copolymer, alginate-graft-polymethacrylamide (Alg-g-PMAM), was then partially hydrolyzed by NaOH solution to yield a hydrogel, hydrolyzed alginate-graft-polymethacrylamide (H-Alg-g-PMAM). During alkaline hydrolysis, the carboxamide groups of Alg-g-PMAM were converted into hydrophilic carboxylate anions. Either the...
Investigation of rock and fluid interactions during engineered water flooding in dolomite reservoir rocks
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 ; Masihi, M ; Safekordi, A. A ; Ayatollahi, S ; Sadeghnejad, S ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Engineered water (EW) flooding is one of the enhanced oil recovery (EOR) techniques in carbonate reservoirs. In this method, the wettability of reservoir rock is altered by controlling the amount of various ions in the injected brine. The thermodynamics of wettability is related to the surface interactions and stability of water film on a rock surface. It can be identified by calculating disjoining pressure isotherms. In this study, core flooding tests, contact angle and zeta potential measurements along with the disjoining pressure isotherm calculation by the DLVO theory were used to investigate the wettability alteration of dolomite rock. Four brines include reservoir formation water...
Effect of SO4 −2 ion exchanges and initial water saturation on low salinity water flooding (LSWF) in the dolomite reservoir rocks
, Article Journal of Dispersion Science and Technology ; Volume 41, Issue 6 , 2020 , Pages 841-855 ; Masihi, M ; Safekordi, A. A ; Ayatollahi, S ; Sadeghnejad, S ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
The low salinity water injection has become one of the most important studies in the oil industry for improving oil recovery compared to conventional seawater injection. Thus, extensive studies have been conducted in carbonate and sandstone reservoirs to investigate how the physical properties of rocks and the chemical composition of fluids influence low salinity effect, while, the carbonate reservoir rocks requires more investigation of the effect of molecular and/or ionic interactions. In this experimental work, the effectiveness of various water flooding schemes in carbonate reservoir rock samples is investigated. In this regard, the oil recovery potential of seawater (SW), reservoir...
Effectiveness of herbicide to control rice weeds in diverse saline environments
, Article Sustainability (Switzerland) ; Volume 13, Issue 4 , 2021 , Pages 1-12 ; 20711050 (ISSN) ; Juraimi, A. S ; Karim, S. M. R ; Khan, M. S. I ; Islam, M. S ; Choudhury, M. K ; Soufan, W ; Alharby, H ; Bamagoos, A ; Iqbal, M. A ; Hnilicka, F ; Kubes, J ; Rahman, M. H. U ; Saud, S ; Hassan, M. M ; Sabagh, A. E. L ; Sharif University of Technology
MDPI AG
2021
Abstract
To mitigate environmental pollution and food contamination caused by inappropriate and excessive herbicide usage, most potent herbicides should be screened to control rice weeds. A research trial was executed for assessing the comparative efficacy of different herbicides to control rice field weeds and to evaluate the toxicity on rice under normal (distilled water) as well as different salinity levels (4 and 8 dS m-1). The study was designed to select the most potent herbicide and its appropriate dose for weed control of rice crop in coastal areas. Fourteen herbicidal treatments were included weed free crop, Pretilachlor (0.25, 0.50, 0.375 and 0.75 kg a.i. ha-1), Propanil + Thiobencarb (0.6...
Minimum control effort trajectory planning and tracking of the CEDRA brachiation robot [electronic resource]
, Article Robotica ; Robotica / Volume 31 / Issue 07 / October 2013, pp 1119-1129 ; Lavasan, S. M. H ; Norouz, M ; Rahimi Mousavi, M. S ; Sharif University of Technology
Abstract
The control of a brachiation robot has been the primary objective of this study. A brachiating robot is a type of a mobile arm that is capable of moving from branch to branch similar to a long-armed ape. In this paper, to minimize the actuator work, Pontryagin's minimum principle was used to obtain the optimal trajectories for two different problems. The first problem considers “brachiation between fixed branches with different distance and height,” whereas the second problem deals with the “brachiating and catching of a moving target branch”. Theoretical results show that the control effort in the proposed method is reduced by 25% in comparison with the “target dynamics” method which was...
Mechanical and piezoelectric characterizations of electrospun PVDF-nanosilica fibrous scaffolds for biomedical applications
, Article 2017 INN International Conference/Workshop on Nanotechnology and Nanomedicine, NTNM 2017, 2 May 2017 through 3 May 2017 ; Volume 5, Issue 7 , 2018 , Pages 15710-15716 ; 22147853 (ISSN) ; Ghaderi, S ; Amini, M ; Ramazani, S. A. A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The effects of hydrophilic and hydrophobic nanosilica (SiO2) on the morphology, mean diameter distribution of fibers, mechanical and piezoelectric properties of poly (vinylidene fluoride) (PVDF) nanofibers were studies. We prepared Nanofibers by the electrospinning of PVDF solutions containing 1.5 wt.% both hydrophilic and hydrophobic nano-SiO2 loadings. Morphology and diameter distribution of the electrospun nanofibers were studied using field emission scanning electron microscopy (FE-SEM) analysis. Tensile test was used to study the effect of both types of nanosilica on the tensile strength, young's modulus and strain at break. Piezoelectric characterization of the electrospun fibers were...
Determining of the optimized dimensions of the Marinelli beaker containing source with inhomogeneous emission rate by using genetic algorithm coupled with MCNP and determining distribution type by neural networks
, Article Applied Radiation and Isotopes ; Volume 157 , 2020 ; Hosseini, S. A ; Feghhi, S. A ; Samadfam, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In order to determine the activity of C137s in soil resulting from nuclear accidents or fallouts, the best choice is to use HPGe detectors due to their best energy resolutions. In this regard, in order to enhance the detection efficiency, the Marinelli beakers have been used to increase the radiation interaction with the sensitive volume of the detector. In previous works, to optimize the dimension of Marinelli beakers, the assumption was that the emission rate of the source is homogeneous in beaker volume. In the present study, to investigate the effect of the inhomogeneous emission rate of the source on the optimum dimensions of the beaker, in a simple case, the beaker was divided into two...