Loading...
Search for:
katanbaf-nezhad--mohamadtaghi
0.12 seconds
Total 240 records
Spectrum Sensing Algorithm and Implementation for Cognitive Radio Applications
, M.Sc. Thesis Sharif University of Technology ; Fotowat Ahmadi, Ali (Supervisor)
Abstract
The continous growth of wireless networks, the increasing numbers of users and devices, along with the demand for higher data rates have intensified the frequency band limitations as the communication medium. In search for more efficient methods to use this limited resource, the cognitive radio approach that allocates the local unused frequency bands to potential users has attracted considerable attension.
A fundamental and unseperable part of any cognitive radio system is its need to search, detect and understand the surrounding frequency spectrum. Although various methods have been already propose to overcome the challenges of this domain, simpler and more reliable methods are still in...
A fundamental and unseperable part of any cognitive radio system is its need to search, detect and understand the surrounding frequency spectrum. Although various methods have been already propose to overcome the challenges of this domain, simpler and more reliable methods are still in...
Cell Sepration of Cancer Cells by Using Electrical Field
, M.Sc. Thesis Sharif University of Technology ; Asempour, Ahmad (Supervisor) ; Ahmadian, Mohamadtaghi (Supervisor)
Abstract
Cancer is the second leading cause of death in the world, with a high annual cost of treatment. As the cancer progresses, the cancer cells in the bloodstream metastasize to other parts of the body, causing the disease to spread throughout the patient's body and disrupt organ functions. sepration of cancer cells in the bloodstream inhibits the growth of cancer. Cancer cells differ from healthy cells in some features, such as size, electrical charge and polarization. These features can be used to seprate cancer cells from healthy cells.In this study, cell surface electrical charge was used as a biomarker to seprate cancer cells. By passing blood flow through a chanal and applying an electrical...
Aggregation-Based Colorimetric Sensor for Determination of Prothioconazole Fungicide Using Colloidal Silver Nanoparticles (AgNPs)
, M.Sc. Thesis Sharif University of Technology ; Hormozi-Nezhad, Mohammad Reza (Supervisor)
Abstract
There is a growing interest in developing high-performance sensors monitoring fungicides, due to their broadly usage and their adverse effects on humans and wildlife. In the present study, a colorimetric probe has been proposed for detection of prothioconazole based on aggregation of unmodified silver nanoparticles (AgNPs). Under optimized condition, linear relationships between the concentration of prothioconazole and the absorbance ratio of A500/A395 were found over the range of 0.01 µg. mL-1 to 0.4 µg. mL-1 with Detection limit as low as 1.7 ng. mL-1. Furthermore, AgNPs color change from yellow to pink-orange in presence of prothioconazole, indicates highly sensitive naked-eye...
Visual recognition of tryptophan enantiomers using chiral self assemblies of quantum dots
, Article ACS Applied Nano Materials ; 2021 ; 25740970 (ISSN) ; Jafar Nezhad Ivrigh, Z ; Bigdeli, A ; Hormozi Nezhad, M.R ; Sharif University of Technology
American Chemical Society
2021
Abstract
Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral...
Visual recognition of tryptophan enantiomers using chiral self assemblies of quantum DOTS
, Article ACS Applied Nano Materials ; Volume 5, Issue 1 , 2022 , Pages 1460-1471 ; 25740970 (ISSN) ; Jafar Nezhad Ivrigh, Z ; Bigdeli, A ; Hormozi Nezhad, M. R ; Sharif University of Technology
American Chemical Society
2022
Abstract
Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral...
Toward visual chiral recognition of amino acids using a wide-range color tonality ratiometric nanoprobe
, Article Analytica Chimica Acta ; Volume 1231 , 2022 ; 00032670 (ISSN) ; Fahimi Kashani, N ; Morad, R ; Jamshidi, Z ; Hormozi Nezhad, M. R ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Chiral recognition has long been a challenging issue to deal with in biological systems, drug design and food authentication. Implementing nanoparticle-based probes with intrinsic or induced chirality in this field has addressed several issues concerning sensitivity, reliability, rapidness and the cost of chiral sensing platforms. Yet, research into chiral nanoprobes that can be used for visual monitoring of chiral substances is still in its infancy. As part of this study, a visual chiral recognition platform has been developed in which a combination of blue-emitting carbon dots (BCDs) and mercaptopropionic acid-capped CdTe quantum dots (MPA-QDs) with inherent chiroptical activity were...
An artificial neural network meta-model for constrained simulation optimization
, Article Journal of the Operational Research Society ; Vol. 65, issue. 8 , August , 2014 , pp. 1232-1244 ; ISSN: 01605682 ; Mahlooji, H ; Sharif University of Technology
2014
Abstract
This paper presents artificial neural network (ANN) meta-models for expensive continuous simulation optimization (SO) with stochastic constraints. These meta-models are used within a sequential experimental design to approximate the objective function and the stochastic constraints. To capture the non-linear nature of the ANN, the SO problem is iteratively approximated via non-linear programming problems whose (near) optimal solutions obtain estimates of the global optima. Following the optimization step, a cutting plane-relaxation scheme is invoked to drop uninformative estimates of the global optima from the experimental design. This approximation is iterated until a terminating condition...
A revised particle swarm optimization based discrete Lagrange multipliers method for nonlinear programming problems
, Article Computers and Operations Research ; Volume 38, Issue 8 , 2011 , Pages 1164-1174 ; 03050548 (ISSN) ; Mahlooji, H ; Sharif University of Technology
2011
Abstract
In this paper, a new algorithm for solving constrained nonlinear programming problems is presented. The basis of our proposed algorithm is none other than the necessary and sufficient conditions that one deals within a discrete constrained local optimum in the context of the discrete Lagrange multipliers theory. We adopt a revised particle swarm optimization algorithm and extend it toward solving nonlinear programming problems with continuous decision variables. To measure the merits of our algorithm, we provide numerical experiments for several renowned benchmark problems and compare the outcome against the best results reported in the literature. The empirical assessments demonstrate that...
Fuzzy simple additive weighting method by preference ratio
, Article Intelligent Automation and Soft Computing ; Volume 11, Issue 4 , 2005 , Pages 235-244 ; 10798587 (ISSN) ; Sadi Nezhad, S ; Sharif University of Technology
2005
Abstract
Although simple additive weighting method (SAW) is the most popular approach for classical multiple attribute decision making (MADM), it is not practical any more if information is fuzzy. The existing methods of Fuzzy Simple Additive Weighting method (FSAW) apply defuzzification which distorts fuzzy numbers. Furthermore, most of the methods usually require lengthy and laborious manipulations. In this paper, we develop a new a fuzzy simple additive weighting method for multiple attribute decision making problems. To avoid defuzzification round off errors caused by multiplication or other arithmetic manipulations, fuzzy numbers are ranked prior to any fuzzy arithmetic in this method. The...
Ranking fuzzy numbers by preference ratio
, Article Fuzzy Sets and Systems, Amsterdam ; Volume 118, Issue 3 , 2001 , Pages 429-436 ; 01650114 (ISSN) ; Sadi Nezhad, S ; Sharif University of Technology
Elsevier Science Publishers B.V
2001
Abstract
We propose a ranking method for fuzzy numbers. In this method a preference function is defined by which fuzzy numbers are measured point by point and at each point the most preferred number is identified. Then, these numbers are ranked on the basis of their preference ratio. Therefore, fuzzy numbers are compared relatively and not necessarily one is preferred absolutely over the others. This method is especially designed to evaluate alternatives in multi criteria or multi-attribute decision making. The method is intuitive and can be used to discriminate between numbers easily. The method is specially tailored for triangular fuzzy numbers (TFN) and an algorithm is presented to determine the...
Design a new strategy based on nanoparticle-enhanced chemiluminescence sensor array for biothiols discrimination
, Article Scientific Reports ; Volume 6 , 2016 ; 20452322 (ISSN) ; Hormozi Nezhad, M. R ; Sharif University of Technology
Nature Publishing Group
2016
Abstract
Array-based sensor is an interesting approach that suggests an alternative to expensive analytical methods. In this work, we introduce a novel, simple, and sensitive nanoparticle-based chemiluminescence (CL) sensor array for discrimination of biothiols (e.g., cysteine, glutathione and glutathione disulfide). The proposed CL sensor array is based on the CL efficiencies of four types of enhanced nanoparticle-based CL systems. The intensity of CL was altered to varying degrees upon interaction with biothiols, producing unique CL response patterns. These distinct CL response patterns were collected as "fingerprints" and were then identified through chemometric methods, including linear...
An ultrasensitive and selective turn-off fluorescent nanoprobe for the detection of copper ions
, Article Analytical Methods ; Volume 7, Issue 12 , 2015 , Pages 5067-5073 ; 17599660 (ISSN) ; Taghipour, M ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
In this study, a novel approach for sensitive and extremely selective detection of copper ions has been developed based on fluorescence resonance energy transfer (FRET) between AuNPs as an acceptor and fluorescein isothiocyanate (FITC) as a donor. Initially, the fluorescence of the FITC molecule turns-off due to adsorption to the AuNPs surface. However, the fluorescence of the FITC-AuNPs system was switched to turn-on by adding d-Pencillamine (d-PC) to the solution mixtures as FITC molecules are released upon displacement by d-PC on the NPs surface. The higher affinity of d-PC toward the surface of AuNPs was further evidenced by controlling the fluorescence intensity enhancement of the...
Quick speciation of iron(II) and iron(III) in natural samples using a selective fluorescent carbon dot-based probe
, Article Analytical Methods ; Volume 8, Issue 20 , 2016 , Pages 4064-4068 ; 17599660 (ISSN) ; Taghipour, M ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
A new, simple and rapid carbon dot (CD) based fluorescent probe for speciation of Fe2+ and Fe3+ ions was developed. The as-prepared CDs contain phenol groups on their surfaces and due to the special coordination interaction of phenol groups with Fe3+ ions, this sensing system exhibits excellent sensitivity and selectivity toward Fe3+. In order to detect Fe2+ ions as well, a specific amount of H2O2 was introduced to the detection system to transform Fe2+ to Fe3+ of which the latter is the determinable form of iron. Under the optimum experimental conditions, the fluorescence intensity of the sensor decreased as the Fe3+ ion concentration increased. The relationship plot between the...
Thermogravimetric analysis and kinetic study of heavy oil pyrolysis
, Article Petroleum Science and Technology ; Volume 34, Issue 10 , 2016 , Pages 911-914 ; 10916466 (ISSN) ; Hami, M. R ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
ABSTRACT: Pyrolysis, so-called devolatilization, is one of the first steps of all thermochemical processes occurring in an inert atmosphere. The authors discuss the main kinetic features of heavy oil pyrolysis, on the basis of the data derived m from a TGA analysis and by using a kinetic model. The samples were heated over a range of temperature from 400 K to 430°C at various heating rates between 10 and 80°C/min. Experimental results showed that the effect of time is considerable in the case of tar conversion, compared to char and gases
Determination and identification of nitroaromatic explosives by a double-emitter sensor array
, Article Talanta ; Volume 201 , 2019 , Pages 230-236 ; 00399140 (ISSN) ; Hormozi Nezhad, M. R ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Detection of nitroaromatic explosives is of strong concern because of human health, public safety, environment, and military issues. In this study, we present a ratiometric sensor array for detection and discrimination of widely-used nitroaromatics (i.e., 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol (TNP), and 2,4-dinitrotoluene (DNT)). In the design of sensor elements (SE) we employ blue emissive carbon dots (BCDs) in combination with yellow (SE-A) and red (SE-B) emissive cadmium telluride quantum dots (CdTe QDs). The fluorescence intensity of BCDs, YQDs, and RQDs is quenched by TNT, DNT, and TNP in various degrees. Both TNT and TNP cause the quenching and spectral shift of BCDs (TNT...
Chemiluminometric fingerprints for identification of plasmonic nanoparticles
, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 209 , 2019 , Pages 85-94 ; 13861425 (ISSN) ; Hormozi Nezhad, M. R ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Development of a convenient and inexpensive method for identification and detection of nanoparticles (NPs) is of great interest. In this work, we have developed a novel and simple chemiluminescence based sensor array, with its sensing mechanism mimicking that of olfactory and gustatory systems for discriminating a set of NPs. The proposed method is based on the enhancement effect of NPs on luminol–oxidant CL intensity by their catalytic effect. Three kinds of oxidant including H2O2, AgNO3, and K3Fe(CN)6 were used as sensor elements and NPs exhibited diverse enhancing responses to different oxidant-luminol CL systems producing unique response patterns that were identified through heat map and...
Decentralized sliding mode control of multistory buildings
, Article Structural Design of Tall and Special Buildings ; Volume 16, Issue 2 , 2007 , Pages 181-204 ; 15417794 (ISSN) ; Rofooei, F. R ; Sharif University of Technology
2007
Abstract
In the present paper, a decentralized control algorithm is considered for actively controlling the response of flexible tall building structures under earthquake excitations. Sliding mode control is used as a base control algorithm and a decentralized scheme of that is presented. In the proposed approach, the building is divided into several substructures and for each subsystem a separate local control algorithm is designed. The control algorithm consists of the sliding surface and the reaching law equations. A numerical example is used to demonstrate the efficiency of the control algorithm in guaranteeing the system's global stability under the effects of subsystem interconnections and...
Investigating the shape evolution mechanism of CdSe quantum dots by chemometrics analysis of spectrophotometry data
, Article Journal of Physical Chemistry C ; Volume 112, Issue 47 , 2008 , Pages 18321-18324 ; 19327447 (ISSN) ; Hormozi Nezhad, M. R ; Sharif University of Technology
2008
Abstract
The study on the mechanism of the shape evolution of nanocrystaline particles is an important and emerging field, which is applicable in the shaped control synthesis of nanoparticles. As an alternative to transmittance electron microscopy (TEM), which is already used in the study of nanoparticles, in this article a simple spectrophotometric method has been proposed utilizing the advantages of chemometrics methods in analyzing overlapped and complex spectral data. The evolutionary visible absorbance data of CdSe quantum dots through particle formation were analyzed by factor analysis, evolving factor analysis, and multivariate curve resolution-alternative least-squares analysis, by which four...
Decentralized control of tall buildings
, Article Structural Design of Tall and Special Buildings ; Volume 15, Issue 2 , 2006 , Pages 153-170 ; 15417794 (ISSN) ; Monajemi Nezhad, S ; Sharif University of Technology
2006
Abstract
The response of large-scale building structures can be actively reduced using an appropriate control algorithm and a number of actuators and sensors located within the building. This paper presents a decentralized control approach for controlling the response of tall buildings. The proposed method aims to divide the structural model into several substructures, each one performing on its own controller algorithm. This approach has already been used in controlling large-scale systems such as power transmission systems and space structures. An instantaneous optimal control scheme is used as the control algorithm with different control feedbacks such as velocity feedback alone and displacement...
Evaluation of the Methods of Circular Tunnels Lining Design Under Seismic Loads
,
M.Sc. Thesis
Sharif University of Technology
;
Paak, Ali
(Supervisor)
Abstract
The use of public transportation in metropolises has developed due to the increase in the population and the need for within-city transportation. Among public transportation service, the use of city subways has attracted more public interest due to its speed, safety, and matching with the environment. Also, one solution for reducing the between-city transit distances,decreasing the accidents and above all, saving the time of the travel is building tunnels and underground lines. Design and construction of underground structures (tunnels),in comparison with surfacestructures, has more complex conditions and considerations that require special studies. One challenging problem fortunnel...