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robatjazi--milad
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Structural Health Monitoring of Elbows, Tee Junctions, Composite to Composite and Composite to Metal Joints for Pressurized Tubular Structures Using Strain and MPCA Algorithm
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
In this thesis, due to the importance of pressurized structures, method or methods that can be used to monitor the health of important structures, such as pressurized pipes (gas transmission and distribution lines or hydraulic lines), are considered. A key point in monitoring such structures is to ensure the function of pipes, elbows, Tee junctions, composite to composite and composite to metal joints. The topic that will be discussed more than anything else here is to monitor the health of the structure in the presence of cracks in some layers of composite pieces. In fact, it must be recognized before cracking occurs in all layers of composite pieces and causing overall damage to the...
Design of an Integrated Interface Circuit for Energy Harvesting from Piezoelectric Devices in Low-Power Applications
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor)
Abstract
In recent years, the Internet of Things (IoT) and wireless sensor networks (WSN) have emerged as key technologies, playing an important role in various industries, including medical applications and remote health monitoring. Despite these applications, providing stable power and the frequent need for battery replacement, especially in environments with limited accessibility, remain fundamental challenges for these systems. Environmental energy harvesting (EH) is an innovative approach to overcome this limitation. Among different energy harvesting methods, piezoelectric technology has been recognized as an efficient option for converting vibrations into electricity due to its high-power...
Does the short-term boost of renewable energies guarantee their stable long-term growth? Assessment of the dynamics of feed-in tariff policy
, Article Renewable Energy ; Volume 159 , October , 2020 , Pages 1252-1268 ; Hamed Shakouri, G ; Mashayekhi, A. N ; Kazemi, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Feed-in tariff (FiT) is one of the most efficient ways that many governments throughout the world use to stimulate investment in renewable energies (REs) technology. For governments, financial management of the policy could be challenging as it needs a considerable amount of budget to support RE producers during the long remuneration period. In this paper, it has been illuminated that the early growth of REs capacity could be a temporary boost. And the socio-economic structure of the system will backlash the policy if some social mechanisms are not considered. Social tolerance for paying REs tax and potential investors’ trust emanated from budget-related mechanisms -which have rarely been...
Spectrophotometric determination of glutathione and cysteine based on aggregation of colloidal gold nanoparticles
, Article Scientia Iranica ; Volume 19, Issue 3 , June , 2012 , Pages 958-963 ; 10263098 (ISSN) ; Seyedhosseini, E ; Robatjazi, H ; Sharif University of Technology
2012
Abstract
We report herein the development of a highly sensitive colorimetric method for the determination of cysteine and glutathione, based on aggregation of the citrate capped gold nanoparticles (Au NPs). This was exploited from high affinity of low-molecular-weight aminothiols towards the Au NPs surface, which could induce displacement of the citrate shell by the thiolate shell of target molecules, resulting in aggregation of the NPs through intermolecular electrostatic interaction or hydrogen-bonding. As a result of aggregation, which can be affected by the ionic strength, pH and concentration of Au NPs, the plasmon band at around 521 nm decreases gradually, along with formation of a new red...
A simple shape-controlled synthesis of gold nanoparticles using nonionic surfactants
, Article RSC Advances ; Volume 3, Issue 21 , 2013 , Pages 7726-7732 ; 20462069 (ISSN) ; Karami, P ; Robatjazi, H ; Sharif University of Technology
2013
Abstract
Green and simple synthesis strategies have gained tremendous popularity for the production of anisotropically-shaped noble metallic nanoparticles. The long-term stability of the produced particles, the short timescale of the target reaction(s), as well as the use of non-toxic chemicals, are pivotal features of a useful green procedure. Herein we describe a simple and convenient wet-chemical approach to synthesize stable, non-toxic and water-soluble small gold nanotriangles (GNTs) and gold nanospheres (GNSs) in one step at room temperature, using Tween 20 and Tween 80, respectively. A high level of purity and monodispersity was obtained for the GNTs, in addition to an excellent colloidal...
Controlling aspect ratio of colloidal silver nanorods using response surface methodology
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 393 , 2012 , Pages 46-52 ; 09277757 (ISSN) ; Jalali Heravi, M ; Robatjazi, H ; Ebrahimi Najafabadi, H ; Sharif University of Technology
2012
Abstract
The properties of metallic nanorods vary due to changes in their composition, size and shape, which all depend on the aspect ratio of the nanorods. This work focuses on the optimization of the aspect ratio of silver nanorods using response surface methodology (RSM). Seed-mediated approach, which is the newest method with less difficulty, has been used for the synthesis of silver nanorods. First, silver ions were reduced with sodium borohydride in the presence of sodium citrate dehydrate, as stabilizer. Then, the prepared seeds were added to a solution containing more metal salts, a weak reducing agent (ascorbic acid) and a rod-like micellar template (cetyltrimethylammonium bromide, CTAB)....
Highly sensitive turn-on fluorescent detection of captopril based on energy transfer between fluorescein isothiocyanate and gold nanoparticles
, Article Journal of Luminescence ; Volume 134 , 2013 , Pages 874-879 ; 00222313 (ISSN) ; Bagheri, H ; Bohloul, A ; Taheri, N ; Robatjazi, H ; Sharif University of Technology
2013
Abstract
A novel approach for highly sensitive detection of captopril was developed based on the fluorescence resonance energy transfer (FRET) between gold nanoparticles (Au NPs) and fluorescein isothiocyanate (FITC), in which FITC acts as the donor and Au NPs as the acceptor. The fluorescence intensity of fluorescein isothiocyanate (FITC) was strictly quenched as a result of noncovalently adsorbed on Au NPs. Upon the addition of captopril, the fluorescence intensity of FITC turn-on due to the competition between captopril and FITC towards the surface of Au NPs. Under the optimum conditions, the fluorescence intensity of the released FITC displays a linear relationship in the range of 20 μg L-1 to...
Application of Experimental Design for Synthesis and Controlling Aspect Ratio of Metallic Nanorods
, M.Sc. Thesis Sharif University of Technology ; Jalali-Heravi, Mehdi (Supervisor) ; ormozi Nezhad, Mohammad Reza (Supervisor)
Abstract
Aspect ratio dependant optical properties of silver and gold nanorods is responsible for great attention toward controlling the aspect ratio of this class of the nanostructure for their application in variety of area, such as medical diagnosis, drug delivery, biosensing and treatment. In this research, gold and silver nanorods have been synthesized using chemical reducation and growth based on seed mediated method, which is the newest and one of the best methods with less difficulty for producing silver and gold nanorods. Absorption of the visible light by gold and silver nanorods results in appearing the longitudinal and transverse Plasmon bands in their absorption spectra which is related...
Colloidal gold nanoparticles: an unexpected catalytic activity in aqueous phase with dioxygen
, Article catalysis letters ; Volume 144, Issue 7 , July , 2014 , pp. 1219-1222 ; 1572-879X ; Robatjazi, H. (Hossein) ; Hormozi-Nezhad, M. (Mohammad Reza) ; Padervand, M. (Mohsen) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
2014
Abstract
Selective oxidations of alkenes were investigated using molecular oxygen in aqueous solution under mild conditions. Colloidal gold nanoparticles are particularly versatile catalysts for oxidation reaction with exceptionally high efficiency and significant selectivity. Gold nanorods (Au NRs) exhibited a slightly enhanced activity compare to gold nanospheres