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Behrooz Vahidi,Amin Mahmoudi 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.3
Finite Volume Method (FVM) is chosen to calculate the heat transfer field and the heat generation with in the cable and heat dissipation in the surrounding soil of a three phase 145kV underground cable brunch that make it possible to analyze the ampacity of the cable. FLUENT as the proper software in this field is used to generate and solve the problem. Non-homogenous environment is considered for cable ampacity calculation and results are compare with homogenous environment condition
Experimental & numerical investigation of mechanical properties in steel fiber-reinforced UHPC
Behrooz Dadmand,Masoud Pourbaba,Hamed Sadaghian,Amir Mirmiran 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.5
This paper presents experimental and numerical investigations on mechanical properties of ultra-high-performance fiber-reinforced concrete (UHPFRC) with four types of steel fibers; micro steel (MS), crimped (C), round crimped (RC) and hooked-end (H), in two fiber contents of 1% and 2% (by volume) and two lengths of 13 and 30 mm. Compression, direct tension, and four-point bending tests were carried out on four types of specimens (prism, cube, dog-bone and cylinder), to study tensile and flexural strength, fracture energy and modulus of elasticity. Results were compared with UHPC specimens without fibers, as well as with available equations for the modulus of elasticity. Specimens with MS fibers had the best performance for all mechanical properties. Among macro fibers, RC had better overall performance than H and C fibers. Increased fibers improved all mechanical properties of UHPFRC, except for modulus of elasticity, which saw a negligible effect (mostly less than 10%). Moreover, nonlinear finite element simulations successfully captured flexural response of UHPFRC prisms. Finally, nonlinear regression models provided reasonably well predictions of flexural load-deflection behavior of tested specimens (coefficient of correlation, R2 over 0.90).
Behrooz Maleki,Mostafa Gholizadeh,Zeinalabedin Sepehr 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.5
A facile, green, efficient and environment-friendly protocol for the synthesis of 14-aryl- or alkyl-14Hdibenzo[a,j]xanthene, 1,8-dioxooctahydroxanthene and 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one have been developed by one-pot condensation of various aldehydes with (i) β-naphthol (ii) cyclic 1,3-dicarbonyl compounds and (iii) β-naphthol and cyclic 1,3-dicarbonyl compounds, in the presence of 1,3,5-trichloro-2,4,6-triazinetrion (trichloroisocyanuric acid, TCCA) as catalyst under solvent-free conditions. The present approach offers the advantages of clean reaction, simple methodology, short reaction time, easy purification, and economic availability of the catalyst.
Behrooz Mohammadparast,Mousa Rasouli,Ali Reza Rustaiee,Sannaz Zardari,Veena Agrawal 한국원예학회 2014 Horticulture, Environment, and Biotechnology Vol.55 No.6
Medicinal plants are nearly unlimited source of phytochemicals. Centella asiatica L. is a tropical medicinalplant with a long history of therapeutic uses, dermal disorders, venous insufficiency micro-angiopathy, and anticancer. The present study highlights (i) in vivo evaluation of asiatic acid (as an anticancer compound) content in differentplant parts of C. asiatica and (ii) in vitro elicitation of asiatic acid employing organic elicitors. Based on the HPLCanalysis, the highest amount of asiatic acid (190.2 μg·g-1 fresh wt.) was found in root part in in vivo condition. Quantitative analyses were done to enhance of asiatic acid content by some organic elicitors. Results showed thehighest quantity of asiatic acid content (258.3 μg·g-1 fw.) among all of the organic elicitors was found at 200 mg·L-1yeast extract in leaf callus cultures. All these observations suggest that exogenous application of organic elicitorscould have induced a subset of secondary metabolite biosynthetic genes, which may modulate expression of genesand accumulation of compounds induced by elicitors.
Behrooz Maleki,Ehsan Esmaeilnezhad,최형진,Ehsan Koushki,Hossein Asghar Rahnamaye Aliabad,Mozafar Esmaeili 한국물리학회 2020 Current Applied Physics Vol.20 No.6
Core-shell structured magnetic Fe3O4@glutathione composite nanoparticles were synthesized and examined using diverse methods including Fourier-transform infrared spectroscopy, X-ray diffraction, energy-dispersive Xray analysis, transmission electron microscope, thermogravimetric analysis, and vibrating sample magnetometer analysis. In addition, the nonlinear optical measurements were performed by both open and closed aperture zscan methods using an aqueous colloidal solution of the fabricated nanoparticles. The colloidal system exhibited a positive nonlinear refractive index because of the self-focusing effect arising from optical re-orientation. Although optical re-orientation is a rare phenomenon in nanocolloids, high polarizability of the enveloping organic ligands caused optical re-orientation of the composite nanoparticles in the electrical field direction of the incident beam. Finally, the effect of external voltage on the nonlinear optical index was further investigated.
Behrooz Zareh-Desari,Mohammad Abaszadeh-Yakhforvazani,Saman Khalilpourazary 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.
The success of a sheet metal forming process is strongly dependent on the performance of provided lubricant at the tool/blank interface. Recent studies have revealed that the tribological properties of lubricating oils can be improved by adding small volume fraction of nanoparticle additives. Nevertheless, the efficiency of Nano-lubricants in actual sheet metal forming processes has not been evaluated so far. In this study, the tribological behavior of Al2O3 nanoparticles dispersed in CM202A press drawing oil was investigated in deep drawing process. Experimental tests were conducted for different concentrations of nanoparticles. The comparison between the formed cups under various lubrication regimes were conducted in terms of surface quality and maximum deformation load. Also, the friction coefficient at die/blank interface was determined inversely by finite element analysis. The results indicated that the friction reduction capability of base oil is enhanced by adding the Al2O3 nanoparticles, which consequently reduces the required forming load. In addition, a noticeable improvement in the surface quality of the formed cups is acquired.
Conjugate finite-step length method for efficient and robust structural reliability analysis
Behrooz Keshtegar 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.4
The Conjugate Finite-Step Length” (CFSL) algorithm is proposed to improve the efficiency and robustness of first order reliability method (FORM) for reliability analysis of highly nonlinear problems. The conjugate FORM-based CFSL is formulated using the adaptive conjugate search direction based on the finite-step size with simple adjusting condition, gradient vector of performance function and previous iterative results including the conjugate gradient vector and converged point. The efficiency and robustness of the CFSL algorithm are compared through several nonlinear mathematical and structural/mechanical examples with the HL-RF and “Finite-Step-Length” (FSL) algorithms. Numerical results illustrated that the CFSL algorithm performs better than the HL-RF for both robust and efficient results while the CFLS is as robust as the FSL for structural reliability analysis but is more efficient.
Distributed Incremental EM Algorithm for Density Estimation in Peer-to-Peer Networks
Behrooz Safarinejadian,Mohammad B. Menhaj,Mehdi Karrari 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
In this paper a distributed incremental EM algorithm (DIEM) is proposed for density estimation and clustering of data distributed over the nodes of a network. Environmental modeling using a sensor network or clustering a data set in a computer network are some of the applications of this algorithm. After a full derivation of the distributed EM algorithm, it will be shown that DIEM converges faster than the standard distributed EM (DEM) algorithm. In DIEM, the data set of each node is partitioned into disjoint blocks of data which incrementally partial E-steps are performed over. Simulation results show that DIEM remarkably outperforms DEM.
Behrooz Minaei Bidgoli,Somayeh Farhang Adib,Samira Yousefi Naghani 한국교육개발원 2014 KEDI Journal of Educational Policy Vol.11 No.2
Iranian society needs a trained expert workforce in light of the rapid advances in science and technology. This is as important as natural needs for community survival, and having an expert workforce leads to independence and power for the society. To this end, governments can facilitate social progress through appropriate and comprehensive planning, training young talent, and optimal use of the available tools and capacities. Considering the importance of expertise in engineering fields for industrialization, this paper investigates the importance and priority of the common engineering disciplines in Iran. To achieve this goal, several criteria must be considered simultaneously, which we did using the Analytic Hierarchy Process. Our findings include a prioritization of the disciplines in this branch of science.
Behrooz Keshtegar,Reza Kolahchi 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.2
First-order reliability method (FORM) is enhanced based on the search direction using relaxed conjugate reliability (RCR) approach for the embedded nanocomposite beam under buckling failure mode. The RCR method is formulated using discrete conjugate map with a limited scalar factor. A dynamical relaxed factor is proposed to control instability of proposed RCR, which is adjusted using sufficient descent condition. The characteristic of equivalent materials for nanocomposite beam are obtained by micro-electro-mechanical model. The probabilistic model of nanocomposite beam is simulated using the sinusoidal shear deformation theory (SSDT). The beam is subjected to external applied voltage in thickness direction and the surrounding elastic medium is modeled by Pasternak foundation. The governing equations are derived in terms of energy method and Hamilton’s principal. Using exact solution, the implicit buckling limit state function of nanocomposite beam is proposed, which is involved various random variables including thickness of beam, length of beam, spring constant of foundation, shear constant of foundation, applied voltage, and volume fraction of ZnO nanoparticles in polymer. The robustness, accuracy and efficiency of proposed RCR method are evaluated for this engineering structural reliability problem. The results demonstrate that proposed RCR method is more accurate and robust than the excising reliability methods-based FORM. The volume fraction of ZnO nanoparticles and the applied voltage are the sensitive variables on the reliable levels of the nanocomposite beams.