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bahadori-nezhad--mehdi
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Spectrofluorimetric Determination of D-penicillamine Using FITC-capped Gold Nanoparticles Via Flourescence Resonance Energy Transfer Mechanism
, M.Sc. Thesis Sharif University of Technology ; Hormozi Nezhad, Mohammad Reza (Supervisor)
Abstract
Recently, fluorescence resonance energy transfer (FRET) based assay through employing gold nanoparticles have been developed for sensitive and selective detection of various analytes [1,2]. These are due to the extremely high extinction coefficient of Au NPs, which induces fluorescence quenching of the attached fluorophores as a result FRET ; a process which is inversely proportional to the sixth power of the distance between fluorophore and quencher [3]. Upon the addition of the analytes with much stronger affinity for Au NPs, the fluorophore molecules are detached from the surface of the Au NPs results in an increase of fluorescence intensity, which is in direct relation with...
A sensitive and selective colorimetric method for detection of copper ions based on anti-aggregation of unmodified gold nanoparticles
, Article Talanta ; Vol. 129, issue , 2014 , pp. 227-232 ; ISSN: 00399140 ; Abbasi-Moayed, S ; Sharif University of Technology
2014
Abstract
A highly sensitive and selective colorimetric method for detection of copper ions, based on anti-aggregation of D-penicillamine (D-PC) induced aggregated gold nanoparticles (AuNPs) was developed. Copper ions can hinder the aggregation of AuNPs induced by D-PC, through formation of mixed-valence complex with D-PC that is a selective copper chelator. In the presence of a fixed amount of D-PC, the aggregation of AuNPs decreases with increasing concentrations of Cu2+ along with a color change from blue to red in AuNPs solution and an increase in the absorption ratio (A520/A 650). Under the optimum experimental conditions (pH 7, [AuNPs] =3.0 nmol L-1 and [NaCl]=25 mmol L-1), a linear calibration...
Lagrangian relaxation heuristics for the uncapacitated single-source multi-product facility location problem
, Article International Journal of Production Economics ; Volume 145, Issue 2 , 2013 , Pages 713-723 ; 09255273 (ISSN) ; Manzour, H ; Salhi, S ; Sharif University of Technology
2013
Abstract
Facility location problem is one of the strategic logistical drivers within the supply chain which is a hard to solve optimization problem. In this study, we focus on the uncapacitated single-source multi-product production/ distribution facility location problem with the presence of set-up cost. To efficiently tackle this decision problem, two Lagrangian-based heuristics are proposed one of which incorporates integer cuts to strengthen the formulation. Local search operators are also embedded within these methods to improve the upper bounds as the search progresses. Three sets of instances with various characteristics are generated and used to evaluate the performance of the proposed...
Gold-nanoparticle-based colorimetric sensor array for discrimination of organophosphate pesticides
, Article Analytical Chemistry ; Volume 88, Issue 16 , 2016 , Pages 8099-8106 ; 00032700 (ISSN) ; Hormozi Nezhad, M. R ; Sharif University of Technology
American Chemical Society
2016
Abstract
There is a growing interest in developing high-performance sensors monitoring organophosphate pesticides, primarily due to their broad usage and harmful effects on mammals. In the present study, a colorimetric sensor array consisting of citrate-capped 13 nm gold nanoparticles (AuNPs) has been proposed for the detection and discrimination of several organophosphate pesticides (OPs). The aggregation-induced spectral changes of AuNPs upon OP addition has been analyzed with pattern recognition techniques, including hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA). In addition, the proposed sensor array has the capability to identify individual OPs or mixtures of them in...
A Visual Colorimetric Probe for Naked-Eye Detection of Pamidronate Disodium in Human Plasma Based on Aggregation of Citrate-Capped Gold Nanoparticles
, Article Plasmonics ; Volume 10, Issue 4 , 2015 , Pages 971-978 ; 15571955 (ISSN) ; Abbasi-Moayed, S ; Sharif University of Technology
Springer New York LLC
2015
Abstract
Herein, a sensitive, simple, and rapid colorimetric assay for the detection of pamidronate disodium was developed based on the aggregation of citrate-capped gold nanoparticles (AuNPs). This was exploited from the affinity of electron-rich atoms toward the surface of AuNPs, resulting in the aggregation of AuNPs through intermolecular hydrogen bonding interactions. As a result of aggregation under optimum conditions ([NaCl] = 25 mM, [AuNPs] = 3.3 nM and pH 7.0), the color of AuNPs was changed from red to blue and the plasmon band of AuNPs around 520 was decreased along with the formation of a new peak at a longer wavelength in the approximate range of 600 to 700 nm. The intensity ratios of...
A colorimetric sensor array for detection and discrimination of biothiols based on aggregation of gold nanoparticles
, Article Analytica Chimica Acta ; Volume 882 , July , 2015 , Pages 58-67 ; 00032670 (ISSN) ; Hormozi-Nezhad, M.R ; Mahmoudi, M ; Sharif University of Technology
Elsevier
2015
Abstract
Developments of sensitive, rapid, and cheap systems for identification of a wide range of biomolecules have been recognized as a critical need in the biology field. Here, we introduce a simple colorimetric sensor array for detection of biological thiols, based on aggregation of three types of surface engineered gold nanoparticles (AuNPs). The low-molecular-weight biological thiols show high affinity to the surface of AuNPs; this causes replacement of AuNPs' shells with thiol containing target molecules leading to the aggregation of the AuNPs through intermolecular electrostatic interaction or hydrogen-bonding. As a result of the predetermined aggregation, color and UV-vis spectra of AuNPs...
Fuzzy analytical hierarchy process using preference ratio: A case study for selecting management short course in a business school
, Article International Journal of Industrial Engineering Computations ; Volume 1, Issue 2 , 2010 , Pages 173-184 ; 19232926 (ISSN) ; Sadi Nezhad, S ; Arabi, F ; Sharif University of Technology
2010
Abstract
Analytic Hierarchy Process (AHP) is one of the most popular approaches in the area of multiple attribute decision making (MADM). However, it is not practical any more if input information are fuzzy. In this paper, we propose a new method for fuzzy AHP which is especially useful to make decisions for multiple attribute problems. The method is developed by applying preference ratio concept which makes it practical since it assigns crisp weights and crisp scores to different alternatives. Two algorithms are proposed in this paper: The first one defines crisp and normalized weight by pairwise comparison with fuzzy data while the second one calculates fuzzy consistency ratio. The proposed method...
Decision-making in detecting and diagnosing faults of multivariate statistical quality control systems
, Article International Journal of Advanced Manufacturing Technology ; Volume 42, Issue 7-8 , 2009 , Pages 713-724 ; 02683768 (ISSN) ; Fallah Nezhad, M. S ; Sharif University of Technology
2009
Abstract
A new methodology is proposed in this paper to both monitor an overall mean shift and classify the states of a multivariate quality control system. Based on the Bayesian rule (Montgomery, Introduction to statistical quality control, 5th edn. Wiley, New York, USA, 2005), the belief that each quality characteristic is in an out-of-control state is first updated in an iterative approach and the proof of its convergence is given. Next, the decision-making process of the detection and classification the process mean shift is modeled. Numerical examples by simulation are provided in order to understand the proposed methodology and to evaluate its performance. Moreover, the in-control and...
Designing an optimum acceptance sampling plan using bayesian inferences and a stochastic dynamic programming approach
, Article Scientia Iranica ; Volume 16, Issue 1 E , 2009 , Pages 19-25 ; 10263098 (ISSN) ; Fallah Nezhad, M. S ; Sharif University of Technology
2009
Abstract
In this paper, we use both stochastic dynamic programming and Bayesian inference concepts to design an optimum-acceptance-sampling-plan policy in quality control environments. To determine the optimum policy, we employ a combination of costs and risk functions in the objective function. Unlike previous studies, accepting or rejecting a batch are directly included in the action space of the proposed dynamic programming model. Using the posterior probability of the batch being in state p (the probability of non-conforming products), first, we formulate the problem into a stochastic dynamic programming model. Then, we derive some properties for the optimal value of the objective function, which...
Gold nanorod-based chrono-colorimetric sensor arrays: a promising platform for chemical discrimination applications
, Article ACS Omega ; Volume 3, Issue 2 , 2018 , Pages 1386-1394 ; 24701343 (ISSN) ; Hormozi Nezhad, M. R ; Sharif University of Technology
American Chemical Society
2018
Abstract
Most array-based sensing platforms, to date, utilize static response patterns for discrimination of a wide variety of analytes, but only a few studies have focused on the important task of quantitatively resolving structural isomers, which are nowadays important because of their broad usage in medicines and industries. A possible way of accomplishing this feat is to combine kinetic (rather than static) sensor response profiles with the chemical tongue strategy to allow the development of array-based sensors for isomeric discrimination. Here, by adding the time dimension, a simple and novel gold nanorod (AuNR)-based chrono-colorimetric sensor array is proposed for chemical discrimination...
CodedSketch: Coded distributed computation of approximated matrix multiplication
, Article 2019 IEEE International Symposium on Information Theory, ISIT 2019, 7 July 2019 through 12 July 2019 ; Volume 2019-July , 2019 , Pages 2489-2493 ; 21578095 (ISSN); 9781538692912 (ISBN) ; Maddah Ali, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose CodedSketch, as a distributed straggler-resistant scheme to compute an approximation of the multiplication of two massive matrices. The objective is to reduce the recovery threshold, defined as the total number of worker nodes that the master node needs to wait for to be able to recover the final result. To exploit the fact that only an approximated result is required, in reducing the recovery threshold, some sorts of pre-compression are required. However, compression inherently involves some randomness that would lose the structure of the matrices. On the other hand, considering the structure of the matrices is crucial to reduce the recovery threshold. In...
Experimental study of continuous h2/air rotating detonations
, Article Combustion Science and Technology ; 2020 ; Fahim, M ; Farshchi, M ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
An experimental study of a lab scale rotating detonation combustor (RDC) has been conducted to identify and classify its modes of operation under different feeding conditions. The chamber uses air as oxidizer and hydrogen as fuel. The stability diagram of the RDC has been determined based on the detonation chamber Reynolds number and reactants mixture equivalence ratio values. The Reynolds number is based on the air volume flow rate, chamber annulus size, and the reactants mixture feeding slot area. Hence the effects of geometrical parameters and operational parameters on the detonation wave stability can be presented in a single stability map. This diagram identifies different zones in...
A smart-phone based ratiometric nanoprobe for label-free detection of methyl parathion
, Article Sensors and Actuators, B: Chemical ; Volume 322 , 2020 ; Hormozi Nezhad, M. R ; Sharif University of Technology
Elsevier B.V
2020
Abstract
The widespread use of pesticides in pest management has boosted the demands for developing highly sensitive probes for on-site monitoring. Herein we presented a sensitive enzyme-free ratiometric probe for determination of methyl parathion (MP), as an organophosphate pesticide using TGA-capped CdTe QDs and carbon dots (CDs). Unlike previous methods in which hydrolysis product of MP is instrumental in the response of the sensors, here, self-assembly of cetyltrimethylammonium bromide (CTAB) on the surface of non-modified yellow-emissive CdTe QDs facilitates the quenching of CTAB-QDs upon addition of MP while the fluorescence intensity of CDs remains constant. Using a smartphone, the ratiometric...
CodedSketch: A coding scheme for distributed computation of approximated matrix multiplication
, Article IEEE Transactions on Information Theory ; Volume 67, Issue 6 , 2021 , Pages 4185-4196 ; 00189448 (ISSN) ; Maddah Ali, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
In this paper, we propose CodedSketch, as a distributed straggler-resistant scheme to compute an approximation of the multiplication of two massive matrices. The objective is to reduce the recovery threshold, defined as the total number of worker nodes that the master node needs to wait for to be able to recover the final result. To exploit the fact that only an approximated result is required, in reducing the recovery threshold, some sorts of pre-compression are required. However, compression inherently involves some randomness that would lose the structure of the matrices. On the other hand, considering the structure of the matrices is crucial to reduce the recovery threshold. In...
A decision making framework in production processes using Bayesian inference and stochastic dynamic programming
, Article Journal of Applied Sciences ; Volume 7, Issue 23 , 2007 , Pages 3618-3627 ; 18125654 (ISSN) ; Fallah Nezhad, M. S ; Sharif University of Technology
Asian Network for Scientific Information
2007
Abstract
In order to design a decision-making framework in production environments, in this study, we use both the stochastic dynamic programming and Bayesian inference concepts. Using the posterior probability of the production process to be in state λ (the hazard rate of defective products), first we formulate the problem into a stochastic dynamic programming model. Next, we derive some properties for the optimal value of the objective function. Then, we propose a solution algorithm. At the end, the applications and the performances of the proposed methodology are demonstrated by two numerical examples. © 2007 Asian Network for Scientific Information
Laminar airfoil shape optimization using an improved genetic algorithm
, Article 46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, 7 January 2008 through 10 January 2008 ; Jun , 2008 ; 9781563479373 (ISBN) ; Khayatzadeh, P ; Nezhad, S. T ; Sharif University of Technology
2008
Abstract
To study efficiency of the genetic algorithms (GAs) in optimization of aerodynamic shapes, shape of an airfoil is optimized by a genetic algorithm to obtain maximum lift to drag ratio and maximum lift. The flow field is assumed to be two dimensional, viscous, and transonic and is analyzed numerically. The camber line and thickness distribution of the airfoil are modeled by a fourth order polynomial. The airfoil chord length is assumed constant. Also, proper boundary conditions are applied. A finite volume method using the first order Roe's flux approximation and time marching (explicit) method is used for flow analysis. The simple genetic algorithm (SGA) is used for optimization. This...
Experimental study of continuous H2/Air rotating detonations
, Article Combustion Science and Technology ; Volume 194, Issue 3 , 2022 , Pages 449-463 ; 00102202 (ISSN) ; Fahim, M ; Farshchi, M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
An experimental study of a lab scale rotating detonation combustor (RDC) has been conducted to identify and classify its modes of operation under different feeding conditions. The chamber uses air as oxidizer and hydrogen as fuel. The stability diagram of the RDC has been determined based on the detonation chamber Reynolds number and reactants mixture equivalence ratio values. The Reynolds number is based on the air volume flow rate, chamber annulus size, and the reactants mixture feeding slot area. Hence the effects of geometrical parameters and operational parameters on the detonation wave stability can be presented in a single stability map. This diagram identifies different zones in...
A new design for floating offshore platforms
, Article Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE ; Volume 1 , 2012 , Pages 529-537 ; 9780791844885 (ISBN) ; England, G. L ; Moradkhan, E ; Valikhani, A. R ; Bahadori, M. R ; Sharif University of Technology
2012
Abstract
While for shallow waters the use of old offshore jackets still seems efficient and justifiable, for deep and ultra-deep waters such platforms cannot be used. During the past few decades the old generation of fixed offshore platforms was succeeded by the new floating platforms and new designs such as FPSOs. A new family of floating offshore platforms has been developed. These should be able to respond to size, weight and space for operating equipment, i.e. they can be constructed to have a wide range of load-bearing capacities. Use is made of the old concept of Life Saving Tubes, which in their simplest form can be a toroidal shaped tyre inner tube. The Torus-shaped idea can be further...
A novel approach for secure and fast generation of RSA public and private keys on SmartCard
, Article Proceedings of the 8th IEEE International NEWCAS Conference, NEWCAS2010, 20 June 2010 through 23 June 2010 ; June , 2010 , Pages 265-268 ; 9781424468058 (ISBN) ; Mali, M. R ; Sarbishei, O ; Atarodi, M ; Sharifkhani, M ; IEEE CAS Society ; Sharif University of Technology
2010
Abstract
RSA based SmartCards have been widely used in security services such as secure data transmission in many applications over the past few years. Generation of a secure key pair which is based on finding a pair of large prime numbers is an indispensable part of creating a secure channel. This paper describes a novel approach for secure and fast key generation of the public key cryptographic algorithm of RSA. This method has been implemented on a typical SmartCard equipped with a crypto-coprocessor and a true random number generator. An efficient method for generating the large random prime numbers is proposed that considerably reduces the total time required for generating a key pair. The key...
Evolving a robust modeling tool for prediction of natural gas hydrate formation conditions
, Article Journal of Unconventional Oil and Gas Resources ; Volume 12 , December , 2015 , Pages 45-55 ; 22133976 (ISSN) ; Mesbah, M ; Shokrollahi, A ; Rozyn, J ; Lee, M ; Kashiwao, T ; Bahadori, A ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Natural gas is a very important energy source. The production, processing and transportation of natural gas can be affected significantly by gas hydrates. Pipeline blockages due to hydrate formation causes operational problems and a decrease in production performance. This paper presents an improved artificial neural network (ANN) method to predict the hydrate formation temperature (HFT) for a wide range of gas mixtures. A new approach was used to define the variables for formation of a hydrate structure according to each species presented in natural gas mixtures. This approach resulted in a strong network with a precise prediction, especially in the case of sour gases. This study also...