Loading...
Search for:
ebrahimi--samaneh
0.126 seconds
Total 441 records
Improvement of nanosilica effects on the performance of mechanically processed styrene-butadiene rubber by rational hybridization with nanodiamond
, Article Diamond and Related Materials ; Volume 130 , 2022 ; 09259635 (ISSN) ; Shojaei, A ; Khasraghi, Samaneh Salkhi ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Hybrid nanoparticle comprising of nanosilica (NS) and nanodiamond (ND), denoted by ND@NS, was synthesized by a two-step chemistry route and then incorporated into styrene-butadiene rubber (SBR) at low concentrations up to 5 phr by a two-roll mill. Physical hybrids of NS and ND, i.e., ND&NS, with a weight ratio similar to chemical hybrid (80:20 for NS:ND), were also incorporated into SBR. Field emission scanning electron microscopy observations revealed very fine dispersion of nanoparticles in the case of physical hybrids (ND&NS). In contrast, agglomerations and aggregation of nanoparticles were evidenced for ND@NS. Tensile and dynamic mechanical analyses exhibited a higher reinforcing effect...
An Investigation on the Role of Silica Hybrid Nanoparticles on the Properties of Styrene Butadiene Rubber (SBR)
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Salkhi Khasraghi, Samaneh (Co-Supervisor)
Abstract
Hybrid nanoparticle comprising of nanosilica (NS) and nanodiamond (ND), as denoted by ND@NS, was synthesized by a two-step chemistry route and then incorporated into styrene-butadiene rubber (SBR) at low concentrations up to 5 phr by a two-roll mill. Physical hybrids of NS and ND, i.e., ND&NS, with a weight ratio similar to chemical hybrid (80:20 for NS:ND), were also incorporated into SBR. Field emission scanning electron microscopy observations revealed very fine dispersion of nanoparticles in the case of physical hybrids (ND&NS); whereas, agglomerations and aggregation of nanoparticles were evidenced for ND@NS. Tensile and dynamic mechanical analyses exhibited a higher reinforcing effect...
Synthesis and Investigation of Properties of Biocompatible Polyurethane Acrylate Based Nanocomposites/Cellulose Nanocrystals
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Salkhi, Samaneh (Co-Supervisor)
Abstract
Bio-based shape memory polymers with fast-response have high potential for use in medical applications. In this study, biocompatible and biodegradable nanocomposites based on shape memory polyurethane acrylates (SMPUA)/cellulose nanocrystals (CNC), were synthesized by in-situ polymerization. CNC is a natural and renewable nanoparticle that has been considered for medical applications due to its excellent mechanical and biological properties and surface chemistry. At the first phase of this study, in order to synthesize UV-curable shape memory polyurethane acrylate, polycaprolactone diol (PCL-Diol), hexamethylene diisocyanate (HDI) and hydroxyethyl methacrylate (HEMA) were used as an reactive...
Synthesis and Evaluation of Poly(lactic Acid)/Polyurethane Nano-composites based on Cellulose Nano-particles, with Biomedical Applications
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Salkhi Khasraghi, Samaneh (Co-Supervisor)
Abstract
Shape memory polymers have the potential to use in the field of biomedical applications. In this research, polyurethane structures have been synthesized based on the Diol mixtures, consisting of polycaprolactane diol (PCL-diol) and poly (lactic acid) diol (PLA-diol). Aim of reasearch is about evaluating poly (lactic acid) effect in structure of the polyurethane. At the same time, cellulose nanocrystals (CNC) have been added to polymer matrix to improve properties. The synthesis of acrylated polyurethane, included the synthesis of polyurethane acrylate prepolymer. Next, this prepolymer has been cured by adding the reactive diluent and some polyol. The cured systems were investigated, finally,...
Synthesis and Investigation of Metal–Organic Framework (MOF) on Properties of Biocompatible Polyurethane Acrylate
, M.Sc. Thesis Sharif University of Technology ; Shojaei Segherlou, Akbar (Supervisor) ; Salkhi Khasraghi, Samaneh (Co-Supervisor)
Abstract
The objective of this research is to evaluate different morphologies of UiO-66 structures (pristine state and UiO-66 structure chemically supported on graphene oxide (UiO-66@GO)), on the rheology of polyurethane acrylate nanocomposites prior to UV-curing. The synthesized nanoparticles were characterized by FTIR, FESEM, TGA, XRD, and BET analysis. Rheological investigations, including large amplitude oscillatory sweep, small amplitude oscillatory sweep, steady shear flow, and thixotropic analysis were utilized. Moreover, the obtained rheological results were fitted using the Carreau–Yasuda model, the power-law model, and the Herschel–Bulkley model for quantitative interpretations. The results...
Investigation the Rule of Carbon-Based Quantum Dot on Biocompatible Polyurethane Acrylate
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Salkhi Khasraghi, Samaneh (Supervisor)
Abstract
Biocompatible materials play a fundamental role in the advancement of medical science and provide groundbreaking solutions for tissue engineering and various therapeutic applications. Among these materials, polyurethane acrylate has attracted attention due to its biocompatibility, versatility, and suitability for creating complex medical scaffolds. This research investigates an innovative approach to reinforce polyurethane acrylate by incorporating graphene quantum dots, with the aim of developing advanced scaffolds for tissue engineering. The incorporation of graphene quantum dots is designed to take advantage of their exceptional properties to improve the mechanical strength, thermal...
A ZVS-resonant bifilar drive circuit for SRM with a reduction in stress voltage of switches
, Article International Aegean Conference on Electrical Machines and Power Electronics, ACEMP 2011 and Electromotion 2011 Joint Conference, Istanbul ; 2013 , Pages 125-128 ; 9781467350037 (ISBN) ; Najmi, V ; Ebrahimi, S ; Oraee, H ; Sharif University of Technology
2013
Abstract
Switched Reluctance Motors (SRMs) are widely used in high-speed and low voltage applications because of their attractive features such as robustness and simplicity. No winding on the rotor of this type of motors allows reaching high speed which is desired for many applications. Drive circuits of SRMs also play an important role in their performance and operation. In this paper, a new bifilar drive circuit for this type of motors has been proposed. This novel configuration has been tested and investigated by PSIM software. Results show that the new bifilar drive circuit highly reduces the voltage stresses on semiconductor switches, and also considerably reduces the switching losses which are...
Energy management of smart home considering residences' satisfaction and PHEV
, Article 2018 International Conference on Smart Energy Systems and Technologies, SEST 2018, 10 September 2018 through 12 September 2018 ; 2018 ; 9781538653265 (ISBN) ; Shokri Gazafroudi, A ; Corchado, J. M ; Ebrahimi, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Regarding the increasing number of electrical devices in the smart homes that leads to increase in total electricity consumption and cost, it is essential to use energy management methods to reduce the electricity cost. However, this can cause resident's dissatisfaction. Hence, it is important to define a method in which cost and dissatisfaction be optimized simultaneously. Among different services, an electric vehicle is the one that can be used as an energy storage system, so it can reduce the daily cost despite of increasing the total energy consumption. In this paper, we study the effect of the EV on the cost and dissatisfaction in our proposed method. © 2018 IEEE
Measured impact of different back-off points and cooling methods on pulse-to-pulse stability and sidelobe level of a high-power solid-state amplifier
, Article IET Radar, Sonar and Navigation ; Volume 14, Issue 2 , 2020 , Pages 335-340 ; Khodarahmi, E ; Ebrahimi, E ; Ahmadi, B ; Jalali, M ; Sharif University of Technology
Institution of Engineering and Technology
2020
Abstract
Using solid-state power amplifiers for next generation of weather radars becomes feasible by pulse compression techniques. In this study a 1.5 kW solid-state power amplifier (transmitter) for C-band weather radars is designed and fabricated by GaN high electron mobility transistor (HEMT) technology. An experimental setup based on heterodyne receiver with 16-bit digitiser is developed to investigate the behavior of the power amplifier under different cooling methods and back-off points. Several measurements with shaped LFM pulse show an approximately identical pulse to pulse (P2P) stability for 3 dB compression, P1dB and 2 dB back-off points while the best sidelobe level (SLL) is achieved for...
Probabilistic safety assessment of a UF 6 production process
, Article Advances in Safety, Reliability and Risk Management - Proceedings of the European Safety and Reliability Conference, ESREL 2011 ; 2012 , Pages 1384-1389 ; 9780415683791 (ISBN) ; Sharif University of Technology
2012
Abstract
Application of Probabilistic Safety Assessment (PSA) to a Uranium hexafluoride (UF 6) production process is presented in this paper. The process is constituted from three main units: UF 4 conversion to UF 6, condensation of produced UF 6 gas and tail gas treatment. Radioactive gas is present in all parts of the process and occurrence of high pressure or high temperature in the process equipments may lead to radioactive release to workplace and environment. The work is mainly based on PSA experience in nuclear power plants. Accordingly for the process, eight group of Initiating Events (IE) that lead to UF 6 gas release have been identified using HAZOP study. For each IE, based on related...
On the temperature control in self-controlling hyperthermia therapy
, Article Journal of Magnetism and Magnetic Materials ; Volume 416 , 2016 , Pages 134-140 ; 03048853 (ISSN) ; Sharif University of Technology
Elsevier
2016
Abstract
In self-controlling hyperthermia therapy, once the desired temperature is reached, the heat generation ceases and overheating is prevented. In order to design a system that generates sufficient heat without thermal ablation of surrounding healthy tissue, a good understanding of temperature distribution and its change with time is imperative. This study is conducted to extend our understanding about the heat generation and transfer, temperature distribution and temperature rise pattern in the tumor and surrounding tissue during self-controlling magnetic hyperthermia. A model consisting of two concentric spheres that represents the tumor and its surrounding tissue is considered and temperature...
Atmospheric icing effects of S816 airfoil on a 600 kW wind turbine's performance
, Article Scientia Iranica ; Volume 25, Issue 5B , 2018 , Pages 2693-2705 ; 10263098 (ISSN) ; Sharif University of Technology
Sharif University of Technology
2018
Abstract
This study investigates the aerodynamic loads and energy losses of a typical 600 kW wind turbine with S816 airfoil blade under two different icing conditions. Three sections at different radial positions were considered to estimate the icing effect along the blade. Ice accretion simulations in wet and dry regimes were carried out using the NASA LEWICE 3.2 computer program. The airflow simulations were performed with CFD method and SST k -ω turbulence model. The results of these simulations, including streamlines, surface pressure, skin friction, lift, and drag coefficients, were inspected for both clean and iced airfoils. In the case of wet iced airfoil, a separation bubble was created in...
Investigation on the Effects of the Polyacrylamide Copolymers and Their Blends with Sulfonated Lignin on the Soil Stabilization
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor) ; Ebrahimi, Hossein (Co-Supervisor)
Abstract
In recent years, dust pollution has become a worldwide issue due to the creation of serious environmental problems and the effects it has on human health. In this research, an environmentally friendly soil stabilizer has been synthesized, and its performance has been investigated. Acrylamide monomers were grafted onto sodium lignosulfonate chains, utilizing solution polymerization. The soil of the Ahvaz deserts was used in the analyses. Using EDX and DLS analyses, the components of this soil and the particle size distribution of the used soil were obtained. Characterization of the functional groups and the structure of the graft copolymer were done by FTIR and H-NMR analysis, respectively,...
Production and Quality Control of 225Ac-PSMA and Absorbed Dose Estimation of its in Different Human Organs
, M.Sc. Thesis Sharif University of Technology ; Hoseini, Abolfazl (Supervisor) ; Shirvani Arani, Simindokht (Supervisor) ; Zolghadri, Samaneh (Co-Supervisor)
Abstract
Prostate cancer is the second leading cause of cancer-related mortality in men after lung cancer. Prostate-specific membrane antigen (PSMA-617) labeled with Actinium-225 (225Ac) is currently being studied as a potential treatment for metastatic castration-resistant prostate cancer. This study aimed to produce the labeled compound [225Ac]Ac-PSMA-617 for the treatment of prostate cancer and its metastases. The compound was synthesized under optimized labeling conditions, and its radiochemical purity was determined to be over %96 using RTLC chromatography method. The biodistribution of the compound was evaluated in the tissues of healthy male mice, and the injected activity per unit mass of...
Dunford-Taylor integral and the isotropic tensor valued functions having the commutative property with their tensor argument
, Article Advanced Materials Research, 16 September 2011 through 18 September 2011 ; Volume 433-440 , September , 2012 , Pages 3308-3314 ; 10226680 (ISSN) ; 9783037853191 (ISBN) ; Asghari, M ; Sharif University of Technology
2012
Abstract
Isotropic tensor valued functions of tensor arguments play an important role in the formulation of the equations governing the behavior of solid materials in the field of continuum mechanics. When the tensor argument is non-symmetric, the complexity and the difficulty in dealing with the tensor functions are high. In this work, the issue of expressing an isotropic tensor valued tensor function of a non-symmetric tensor argument is attention by utilizing the Dunford-Taylor integral. An important subclass of the isotropic tensor functions is considered with the commutative property
Formaldehyde biodegradation using an immobilized bed aerobic bioreactor with pumice stone as a support
, Article Scientia Iranica ; Volume 18, Issue 6 , December , 2011 , Pages 1372-1376 ; 10263098 (ISSN) ; Borghei, M ; Sharif University of Technology
2011
Abstract
The objective of this study is the investigation of formaldehyde degradation in a bioreactor with pumice stone as a support. The reactor was tested at different synthetic wastewater concentrations with total COD of 500, 1000 and 1500 mgL, respectively, at 24 h hydraulic retention time. The effect of feed composition was tested by changing the COD TCOD FA ratio in order to analyze the impact of formaldehyde concentration. The average formaldehyde and COD removal efficiencies obtained in the reactor were 97.1% and 88%, respectively. The maximum COD and formaldehyde removal efficiencies occurred at the COD TCOD F of 41 at COD T=1000mgL. The effect of toxic shock on reactor performance was...
Port-Hamiltonian control of a brachiating robot via generalized canonical transformations
, Article 2016 American Control Conference, ACC 2016, 6 July 2016 through 8 July 2016 ; Volume 2016-July , 2016 , Pages 3026-3031 ; 07431619 (ISSN); 9781467386821 (ISBN) ; Namvar, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
This paper is devoted to the design of a port Hamiltonian controller for different scenarios of brachiation movement by a two-link bio-inspired robot called brachiating robot. A unified technique for trajectory tracking control problem of nonholonomic (drift-less) port Hamiltonian systems was introduced in the past, which exploits a generalized canonical transformation to form an error system in order to convert the trajectory tracking problem into a stabilization one. Although the method is novel and promising, only fully actuated systems are considered and success of the approach relies on the possibility of solving a set of partial differential equations (PDEs). Considering the fact that...
Numerical investigation of the forward and backward travelling waves through an undulating propulsor: performance and wake pattern
, Article Ships and Offshore Structures ; Volume 11, Issue 5 , 2016 , Pages 517-539 ; 17445302 (ISSN) ; Abbaspour, M ; Sharif University of Technology
Taylor and Francis Ltd
2016
Abstract
Recently, the mechanisms of natural undulatory locomotion of aquatic animal swimming have become one of the most significant issues for the researchers, swimmers and engineers. This study aims to elucidate and compare the propulsive vortical signature and performance of backward (negative undulation) and forward (positive undulation) travelling waves through a typical fishlike propulsor by a systematic numerical study. The numerical approach uses a pressure-based finite volume method solver to solve Navier–Stokes equations in an arbitrary Lagrangian–Eulerian framework domain containing a two-dimensional NACA 0012 foil moving with prescribed kinematics. Some of the important findings are: (1)...
A comparative numerical study on the performances and vortical patterns of two bioinspired oscillatory mechanisms: Undulating and pure heaving
, Article Applied Bionics and Biomechanics ; Volume 2015 , 2015 ; 11762322 (ISSN) ; Abbaspour, M ; Sharif University of Technology
IOS Press
2015
Abstract
The hydrodynamics and energetics of bioinspired oscillating mechanisms have received significant attentions by engineers and biologists to develop the underwater and air vehicles. Undulating and pure heaving (or plunging) motions are two significant mechanisms which are utilized in nature to provide propulsive, maneuvering, and stabilization forces.This study aims to elucidate and compare the propulsive vortical signature and performance of these two important natural mechanisms through a systematic numerical study. Navier-Stokes equations are solved, by a pressure-based finite volume method solver, in an arbitrary Lagrangian- Eulerian (ALE) framework domain containing a 2D NACA0012 foil...
Numerical investigation of the forward and backward travelling waves through an undulating propulsor: performance and wake pattern
, Article Ships and Offshore Structures ; Apr , 2015 ; 17445302 (ISSN) ; Abbaspour, M ; Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
Recently, the mechanisms of natural undulatory locomotion of aquatic animal swimming have become one of the most significant issues for the researchers, swimmers and engineers. This study aims to elucidate and compare the propulsive vortical signature and performance of backward (negative undulation) and forward (positive undulation) travelling waves through a typical fishlike propulsor by a systematic numerical study. The numerical approach uses a pressure-based finite volume method solver to solve Navier–Stokes equations in an arbitrary Lagrangian–Eulerian framework domain containing a two-dimensional NACA 0012 foil moving with prescribed kinematics. Some of the important findings are: (1)...