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An experimental study of time lag for pressure measurement in different tubes
, Article Amirkabir (Journal of Science and Technology) ; Volume 16, Issue 61 B , 2005 , Pages 127-137 ; 10150951 (ISSN) ; Soltani, M. R ; Tolouei, E ; Sharif University of Technology
2005
Abstract
Determination of the time lag caused by utilization of different tubes to measure pressure on the surface of a wind tunnel model is an important problem in the field of aerodynamic especially for unsteady measurements where the pressure signature changes continuously with time. In this investigation the time required for the applied pressure at one end of different tubes to reach its original value (applied pressure) at the other end has been measured. Three plastic tubes and two polyethylene tubes with different lengths and different inner diameters; L=2, 5 and 10 m, d=1, 2 and 4 mm, were used to study the time lag. Experimental data show that the response time in a pressure measuring...
Comparison of River Daily Runoff Simulation Results using Time Series and IHACRES Rainfall-runoff Model
, M.Sc. Thesis Sharif University of Technology ; Shamsaei, Abolfazl (Supervisor)
Abstract
Hydrologic models are the best tools to reduce hydrological uncertainties in rivers runoff estimation. Considering structure of model and calibration of parameters, there are several approaches to extend. In this study, we try to simulate daily river runoff by using two different approaches and then compare the results of them with each other. In first approach, IHACRES model is used to simulate rainfall- runoff, which is a conceptual model based on rainfall, runoff and evapotranspiration or temperature data. This model uses conceptual part to estimate effective rainfall and also it uses a transformation function to transform effective rainfall to output flow. This model works in daily time...
Modeling, Localization and Control of Endoscopic Capsule for Tissue Biopsy
,
M.Sc. Thesis
Sharif University of Technology
;
Nejat Pishkenari, Hossein
(Supervisor)
Abstract
Nowadays, endoscopic capsules are an interesting technique due to their ability to minimize patient discomfort and provide access to all parts of the gastrointestinal tract. However, they lack some capabilities of traditional methods, such as performing biopsies. An essential requirement for performing a biopsy of a specific part of the gastrointestinal tract is capsule control; in addition, localization information is required for closed-loop control. The goal of this research is the localization and control of a capsule with a biopsy module. For this purpose, an endoscopic capsule using the concept of a magnetic spring was introduced, which had different magnets so its localization and...
Effects of lithium excess and Ni content on the electrochemical performance of Li1+x (Ni0.45-xMn0.4Co0.15) O2 lithium-ion cathode materials in stoichiometric state
, Article Materials Research Express ; Volume 6, Issue 8 , 2019 ; 20531591 (ISSN) ; Kaflou, A ; Sadrnezaad, S. K ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
In Li-ion batteries, application of active materials can enhance the kinetics of the charge-discharge process, reduce the costs and improve the safety of the system. In this work, the effect of nickel content and lithium excess in Li1+x (Ni0.4-xMn0.5Co0.1) O2 compounds on the electrochemical performance of the lithium-ion battery cathode have been studies. For this purpose, three compounds of NMC in the stoichiometric state were synthesized via co-precipitation as the cathode active material. XRF and EDS analyses indicate that precursors and oxide compounds are well synthesized. The final compound of synthesized cathodes was obtained by ICP analysis. XRD results also suggest that the...
Flow analysis around a pitching airfoil
, Article Collection of Technical Papers - 22nd AIAA Applied Aerodynamics Conference, Providence, RI, 16 August 2004 through 19 August 2004 ; Volume 2 , 2004 , Pages 914-924 ; 10485953 (ISSN) ; Mani, M ; Soltani, M. R ; Boroomand, M ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2004
Abstract
A series of low-speed wind tunnel tests were performed to investigate the unsteady pressure distribution over an airfoil. Dynamic pitching motion was produced by oscillating the model over a range of reduced frequencies, k=0.022 - 0.066. In addition, steady data were acquired and examined to furnish as a baseline for analysis and comparison. The model was oscillated between 0-18° angle of attack. Surface static pressure was measured from x/c=5-80% for both upper and lower surfaces. The pressure coefficients in the low angle of attack range showed little overshoot when compared with the static values, while for the large angle of attack cases the differences were significant. For a constant...
Microemulsion synthesis of nanoparticle PZT powder
, Article AIP Conference Proceedings, 24 October 2010 through 27 October 2010 ; Volume 1315 , 2010 , Pages 265-270 ; 0094243X (ISSN) ; 9780735408715 (ISBN) ; Nemati, Z. A ; Rahmanifar, M. S ; Ramesh, S ; Meenaloshini, S ; Tolouei, R ; Sharif University of Technology
2010
Abstract
Nanocrystalline lead zirconate titanate (PZT) powders have been synthesized using microemulsion processing route. Microemulsion is one of the major processing techniques to synthesize a nanosize, homogenous, and almost agglomerate free ceramic powders. The ternary microemulsion system is consisted of cyclohexane as the oil phase, Triton X100 as the nonionic surfactant phase, and an aqueous phase containing 0.619MPb 2+, 0.325MZr 4+, and 0.3MTi 4+, representing a Pb 2+: Zr 4+: Ti 4+ molar ratio of 1:0.52:0.48. The ratio of these cations has been adjusted using Inductively Coupled Plasma (ICP) technique. After coprecipitation of metallic hydroxides by adding ammonia solution in microemulsion...
Study of microstructure and dielectric properties of PMN-PZT ceramics via a mixed powder method including microemulsion derived PZT powder
, Article Malaysian Journal of Microscopy ; Volume 7, Issue 1 , 2011 , Pages 43-47 ; 18237010 (ISSN) ; Nemati, Z. A ; Meenaloshini, S ; Sankar, U ; Tolouei, R ; Rahmanifar, M. S ; Ramesh, S ; Sharif University of Technology
2011
Abstract
In this research, (X)PZT-(1-X)PMN ceramics (where X is 0.25, 0.5 and 0.75) were achieved from a conventional mixed-oxide method. Lead Zirconate titanate (PZT) powders with composition near the morphotropic phase boundary have been synthesized via a microemulsion processing route. Modified mixed oxides method was used for obtaining single phase Lead Magnesium niobate (PMN) powder with high relative density (98% of T.D.) and good electrical properties (dielectric constant of ≈10 4 at room temperature). Two-step sintering (TSS) has been applied to suppress the accelerated grain growth of PZT-PMN composite compacts in the last sintering stage. The produced samples with high PZT content showed...
Dose-dependent effects of nanoscale graphene oxide on reproduction capability of mammals
, Article Carbon ; Volume 95 , December , 2015 , Pages 309-317 ; 00086223 (ISSN) ; Ghaderi, E ; Hashemi, E ; Akbari, E ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In vivo dose-dependent effects of nanoscale graphene oxide (NGO) sheets on reproduction capability of Balb/C mice were investigated. Biodistribution study of the NGO sheets (intravenously injected into male mice at dose of ∼2000 μg/mL or 4 mg/kg of body weight) showed a high graphene uptake in testis. Hence, in vivo effects of the NGO sheets on important characteristics of spermatozoa (including their viability, morphology, kinetics, DNA damage and chromosomal aberration) were evaluated. Significant in vivo effects was found at the injected concentrations ≥200 μg/mL after (e.g., ∼45% reduction in sperm viability and motility at 2000 μg/mL). Observation of remarkable DNA fragmentations and...
Accelerated differentiation of neural stem cells into neurons on ginseng-reduced graphene oxide sheets
, Article Carbon ; Volume 66 , January , 2014 , Pages 395-406 ; Ghaderi, E ; Abouei, E ; Hatamie, S ; Ghasemi, E ; Sharif University of Technology
2014
Abstract
Asian red ginseng was used for green reduction of chemically exfoliated graphene oxide (GO) into reduced graphene oxide (rGO). The reduction level and electrical conductivity of the ginseng-rGO sheets were comparable to those of hydrazine-rGO ones. Reduction by ginseng resulted in repairing the sp 2 graphitic structure of the rGO, while hydrazine-rGO showed more defects and/or smaller aromatic domains. The ginseng-rGO sheets presented a better stability against aggregation than the hydrazine-rGO ones in an aqueous suspension. Whilst the hydrophobic hydrazine-rGO films exhibited no toxicity against human neural stem cells (hNSCs), the hydrophilic GO and ginseng-rGO films (as more...
Contested framings and policy controversies: Analysing biosafety policy-making in Iran
, Article Science and Public Policy ; Volume 40, Issue 5 , 2013 , Pages 616-627 ; 03023427 (ISSN) ; Millstone, E ; Sharif University of Technology
2013
Abstract
Vigorous debates have taken place within and between many countries about regulatory policy regimes covering the assessment and approval of genetically modified (GM) crops. In Iran, a very vigorous and hotly contested policy debate concerning legislation covering GM crops occurred between 2004 and 2009, but it was confined within government circles with almost no public discussion. This paper analyses the Iranian policy-making process in the period 2006-9. It explains how and why a stalemate arose in disputes between ministries and departments. The chosen analytical framework draws mainly on the regulation of technological risks and the analysis of public policy-making. It deploys the...
On the possible volumes of μ-way latin trades
, Article Aequationes Mathematicae ; Volume 63, Issue 3 , 2002 , Pages 303-320 ; 00019054 (ISSN) ; Billington, E. J ; Bryant, D. E ; Mahmoodian, E. S ; Sharif University of Technology
Birkhauser Verlag Basel
2002
Abstract
A μ-way latin trade of volume s is a set of μ partial latin rectangles (of inconsequential size) containing exactly the same s filled cells, such that if cell (i, j) is filled, it contains a different entry in each of the μ partial latin rectangles, and such that row i in each of the μ partial latin rectangles contains, set-wise, the same symbols and column j, likewise. In this paper we show that all μ-way latin trades with sufficiently large volumes exist, and state some theorems on the non-existence of μ-way latin trades of certain volumes. We also find the set of possible volumes (that is, the volume spectrum) of μ-way latin trades for μ = 4 and 5. (The case μ = 2 was dealt with by Fu,...
The three-way intersection problem for latin squares
, Article Discrete Mathematics ; Volume 243, Issue 1-3 , 2002 , Pages 1-19 ; 0012365X (ISSN) ; Billington, E. J ; Bryant, D. E ; Mahmoodian, E. S ; Sharif University of Technology
2002
Abstract
The set of integers k for which there exist three latin squares of order n having precisely k cells identical, with their remaining n2 -k cells different in all three latin squares, denoted by I3[n], is determined here for all orders n. In particular, it is shown that I3[n] = {0,.,n2 -15}U [n2 - 12,n2-9,n2], for n ≫8. ©2002 Eisevier Science B.V. All rights reserved
Integration of spatial fuzzy clustering with level set for segmentation of 2-D angiogram
, Article IECBES 2014, Conference Proceedings - 2014 IEEE Conference on Biomedical Engineering and Sciences: "Miri, Where Engineering in Medicine and Biology and Humanity Meet", 8 December 2014 through 10 December 2014 ; December , 2015 , Pages 309-314 ; 9781479940844 (ISBN) ; Zahedi, E ; Fatemizadeh, E ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Coronary angiography is a vital instrument to detect the prevailing of vascular diseases, and accurate vascular segmentation acts a crucial role for proper quantitative analysis of the vascular tree morphological features. Level set methods are popular for segmenting the coronary arteries, but their performance is related to suitable start-up and optimum setting of regulating parameters, essentially done manually. This research presents a novel fuzzy level set procedure with the objective of segmentation of the coronary artery tree in 2-D X-ray angiography as automatically. It is clever to clearly develop from the early segmentation with spatial fuzzy grouping. The adjusting parameters of...
Deep relative attributes
, Article 13th Asian Conference on Computer Vision, ACCV 2016, 20 November 2016 through 24 November 2016 ; Volume 10115 LNCS , 2017 , Pages 118-133 ; 03029743 (ISSN); 9783319541921 (ISBN) ; Noury, E ; Adeli, E ; Sharif University of Technology
Springer Verlag
2017
Abstract
Visual attributes are great means of describing images or scenes, in a way both humans and computers understand. In order to establish a correspondence between images and to be able to compare the strength of each property between images, relative attributes were introduced. However, since their introduction, hand-crafted and engineered features were used to learn increasingly complex models for the problem of relative attributes. This limits the applicability of those methods for more realistic cases. We introduce a deep neural network architecture for the task of relative attribute prediction. A convolutional neural network (ConvNet) is adopted to learn the features by including an...
A public code for astrometric microlensing with contour integration
, Article Monthly Notices of the Royal Astronomical Society ; Volume 505, Issue 1 , 2021 , Pages 126-135 ; 00358711 (ISSN) ; Khalouei, E ; Bachelet, E ; Sharif University of Technology
Oxford University Press
2021
Abstract
We present the first public code for the calculation of the astrometric centroid shift occurring during microlensing events. The computation is based on the contour integration scheme and covers single and binary lensing of finite sources with arbitrary limb darkening profiles. This allows for general detailed investigations of the impact of finite source size in astrometric binary microlensing. The new code is embedded in version 3.0 of vbbinarylensing, which offers a powerful computational tool for extensive studies of microlensing data from current surveys and future space missions. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Toward electrically tunable, lithography-free, ultra-thin color filters covering the whole visible spectrum
, Article Scientific Reports ; Volume 8, Issue 1 , 2018 ; 20452322 (ISSN) ; Serebryannikov, A. E ; Khavasi, A ; Vandenbosch, G. A. E ; Ozbay, E ; Sharif University of Technology
Nature Publishing Group
2018
Abstract
The possibility of real-time tuning of optical devices has attracted a lot of interest over the last decade. At the same time, coming up with simple lithography-free structures has always been a challenge in the design of large-area compatible devices. In this work, we present the concept and the sample design of an electrically tunable, lithography-free, ultra-thin transmission-mode color filter, the spectrum of which continuously covers the whole visible region. A simple Metal-Insulator-Metal (MIM) cavity configuration is used. It is shown that using the electro-optic dielectric material of 4-dimethyl-amino-N-methyl-4-stilbazoliumtosylate (DAST) as the dielectric layer in this...
A novel method for modeling the magnetizing yoke
, Article Electromagnetics ; Volume 30, Issue 3 , 2010 , Pages 297-308 ; 02726343 (ISSN) ; Norouzi, E
2010
Abstract
Magnetic flux leakage is the most widely used method for oil and gas pipeline non destructive testing. The saturation level of the sample under test has a significant effect on its efficiency; therefore, the magnetizing yoke requires an elaborate design. The finite element method is the conventional approach used for this purpose, but it is very time consuming. In this article, a neuro-fuzzy method is presented to model the behavior of the magnetizing yoke. Modeling a few different designs with the finite element method and using the results for training the neuro-fuzzy model eradicates the necessity of modeling a huge number of designs with the finite element method. The acquired...
On decomposing complete tripartite graphs into 5-cycles
, Article Australasian Journal of Combinatorics ; Volume 54, Issue 2 , 2012 , Pages 289-301 ; 10344942 (ISSN) ; Mahmoodian, E. S ; Mollaahmadi, E ; Sharif University of Technology
AJC
2012
Abstract
The problem of finding necessary and sufficient conditions to decompose a complete tripartite graph K(r, s, t) into 5-cycles was first considered by Mahmoodian and Mirzakhani (1995). They stated some necessary conditions and conjectured that these conditions are also sufficient. Since then, many cases of the problem have been solved by various authors; however the case when the partite sets r ≤ s ≤ t have odd and distinct sizes remains open. A necessary condition is t ≤ 3r. Billington and Cavenagh (2011) have shown that when r, s, and t are all odd and r ≤ s ≤ t ≤ κr, where κ ≈ 1.0806, then the conjectured necessary conditions for decomposing are also sufficient. We extend this result...
Numerical simulation of hybrid nanofluid flow and heat transfer across parallel surfaces with suction/injection and magnetic effect
, Article Numerical Heat Transfer; Part A: Applications ; 2024 ; 10407782 (ISSN) ; Bilal, M ; Ali, A ; Abouel Nasr, E ; Azzouz, S ; Mahmoud, E. E ; Sharif University of Technology
2024
Abstract
The heat and mass transfer through the hybrid nanofluid (Hnf) flow with the significance of magnetic field across two spinning parallel plates has been described. The Hnf is prepared by the dispersion of SiO2 (Silicon dioxide) and MoS2 (Molybdenum Disulfide) nanoparticles (NPs) in the ethylene glycol (EG). The MoS2 is anti-friction compound used in automobiles and other types of heavy machineries in industry. It reduces the engine noise, reduces fuel consumption and enhances engine life. Similarly, SiO2 is used in structural materials, food processing, pharmaceutical industries and as an electrical insulator in microelectronic apparatus. Based on the remarkable applications of the hybrid...
Ultra-sensitive detection of leukemia by graphene
, Article Nanoscale ; Vol. 6, issue. 24 , Dec , 2014 , p. 14810-14819 ; Ghaderi, E ; Hashemi, E ; Rahighi, R ; Sharif Universit of Technology
2014
Abstract
Graphene oxide nanoplatelets (GONPs) with extremely sharp edges (lateral dimensions ∼20-200 nm and thicknesses <2 nm) were applied in extraction of the overexpressed guanine synthesized in the cytoplasm of leukemia cells. The blood serums containing the extracted guanine were used in differential pulse voltammetry (DPV) with reduced graphene oxide nanowall (rGONW) electrodes to develop fast and ultra-sensitive electrochemical detection of leukemia cells at leukemia fractions (LFs) of ∼10-11 (as the lower detection limit). The stability of the DPV signals obtained by oxidation of the extracted guanine on the rGONWs was studied after 20 cycles. Without the guanine extraction, the DPV peaks...