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Petroleum Science 2013年第3期10卷 373-384页

作者： Behrouz Asgarian hamed Rahman Shokrgozar Department of Civil Engineering K. N. Toosi University of TechnologyNo. 1346 Valiasr Street Mirdamad Intersection 19967 P.O. Box. 15875-4416Tehran Iran

In this paper, the seismic response of a newly designed steel jacket offshore platform with a float over deck （FOD） system in the Persian Gulf was investigated through incremental dynamic analysis. Comparison of incremental dynamic analysis results for both directions of the platform shows that the lateral strength of the platform in the float over direction is less than its lateral strength in other direction. Dynamic characteristics measurement of a scale model of platform was also performed using forced vibration tests. From experimental measurement of the scaled model, it was observed that dynamic characteristic of the platform is different in the float over direction compared to the other direction. Therefore, a new offshore installed bracing system for the float over direction was proposed for improvement of seismic performance of this type of platform. Finally, the structure with the modified system was assessed using the probabilistic seismic assessment method as well as experimental measurement of its dynamic characteristics. It was observed that the proposed offshore installed bracing system improves the performance of platforms subjected to strong ground motion.

关键词： Steel jacket type offshore platform float-over deck mean annual frequency force vibration test seismic performance dynamic characteristics

Microstructural characteristics and mechanical properties of Al-2024 alloy processed via a rheocasting route

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International Journal of Minerals,Metallurgy and Materials 2015年第1期22卷 59-67页

作者： Behnam Rahimi hamed khosravi Mohsen Haddad-Sabzevar Department of Metallurgy and Materials Engineering Faculty of EngineeringFerdowsi University of Mashhad Faculty of Materials Science and Engineering K.N.Toosi University of Technology

This article reports the effects of stirring speed and T6 heat treatment on the microstructure and mechanical properties of Al-2024 alloy synthesized by a rheocasting process. There was a decrease in grain size ofα-Al particles corresponding to an increase in stirring speed. By increasing the stirring speed, however, the globularity of matrix particles first increased and then declined. It was also found that the hardness, compressive strength, and compressive strain increased with the increase of stirring speed. Microstructural studies revealed the presence of nonsoluble Al15（CuFeMn）3Si2 phase in the vicinity of CuAl2 in the rheocast samples. The required time for the solution treatment stage was also influenced by stirring speed;the solution treatment time decreased with the increase in stirring speed. Furthermore, the rheo-cast samples required a longer homogenization period compared to conventionally wrought alloys. Improvements in hardness and compres-sive properties were observed after T6 heat treatment.

关键词： aluminum alloys rheocasting microstructure mechanical properties

Effectiveness of two conventional methods for seismic retrofit of steel and RC moment resisting frames based on damage control criteria

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Earthquake Engineering and Engineering Vibration 2017年第3期16卷 537-555页

作者： Seyed Bahram Beheshti Aval hamed Sadegh kouhestani Lida Mottaghi Faculty of Civil Engineering K. N. Toosi University of Technology Tehran 1ran Faculty of Technical and Engineering Science & Culture University Tehran 1ran

This study investigates the efficiency of two types of rehabilitation methods based on economic justification that can lead to logical decision making between the retrofitting schemes. Among various rehabilitation methods, concentric chevron bracing（CCB） and cylindrical friction damper（CFD） were selected. The performance assessment procedure of the frames is divided into two distinct phases. First, the limit state probabilities of the structures before and after rehabilitation are investigated. In the second phase, the seismic risk of structures in terms of life safety and financial losses（decision variables） using the recently published FEMA P58 methodology is evaluated. The results show that the proposed retrofitting methods improve the serviceability and life safety performance levels of steel and RC structures at different rates when subjected to earthquake loads. Moreover, these procedures reveal that financial losses are greatly decreased, and were more tangible by the application of CFD rather than using CCB. Although using both retrofitting methods reduced damage state probabilities, incorporation of a site-specific seismic hazard curve to evaluate mean annual occurrence frequency at the collapse prevention limit state caused unexpected results to be obtained. Contrary to CFD, the collapse probability of the structures retrofitted with CCB increased when compared with the primary structures.

关键词： steel and RC moment resisting frames seismic retrofitting collapse probability concentric chevron bracing(CCB) cylindrical friction damper (CFD)

Studies on composite solid propellant with tri-modal ammonium perchlorate containing an ultrafine fraction

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Defence Technology（防务技术） 2017年第4期13卷 239-245页

作者： k.V. Suresh Babu P. kanaka Raju C.R. Thomas A. Syed hamed k.N. Ninan Solid Propellant Space Booster Plant Satish Dhawan Space Centre Sriharikota 524124 India Rocket Propellant Plant Vikram Sarabhai Space Centre Thiruvananthapuram 695 022 India Department of Chemistry Indian Institute of Space Science and Technology Thiruvananthapuram 695 547 India

Composite solid propellant is prepared using tri-modal Ammonium perchlorate(AP)containing coarse,fine and ultrafine fractions of AP with average particle size(APS)340,40 and 5 mm respectively,in various compositions and their rheological,mechanical and burn rate characteristics are *** optimum combination of AP coarse to fine to ultrafine weight fraction was obtained by testing of series of propellant samples by varying the AP fractions at fixed solid *** concentration of aluminium was maintained constant throughout the experiments for ballistics *** propellant formulation prepared using AP with coarse to fine to ultrafine ratio of 67:24:9 has lowest viscosity for the propellant paste and highest tensile strength due to dense packing as supported by the literature.A minimum modulus value was also observed at 9 wt.%of ultrafine AP concentration indicates the maximum solids packing density at this ratio of AP *** burn rate is evaluated at different pressures to obtain pressure *** of ultrafine fraction of AP in propellant increased burn rate without adversely affecting the pressure *** solid loading propellants are prepared by increased AP concentration from 67 to 71 wt.%using AP with coarse to fine to ultrafine ratio of67:24:*** solid content up to 89 wt.%was achieved and hence increased solid motor *** unloading viscosity showed a trend with increased AP content and the propellant couldn't able to cast beyond 71 wt.%of *** properties were also studied and from the experiments noticed that%elongation decreased with increased AP content from 67 to 71 wt.%,whereas tensile strength and modulus *** rate increased with increased AP content and observed that pressure exponent also increased and it is high for the propellant containing with 71 wt.%of AP due to increased oxidiser to fuel *** composite solid propellant is prepared by using burn rate modifie

关键词： Ammonium perchlorate Composite propellant Burn rate Copper chromite Iron oxide

Continuous and Discrete Adjoint Approach Based on Lattice Boltzmann Method in Aerodynamic Optimization Part I:Mathematical Derivation of Adjoint Lattice Boltzmann Equations

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Advances in Applied Mathematics and Mechanics 2014年第5期6卷 570-589页

作者： Mohamad hamed Hekmat Masoud Mirzaei Center of Excellence for Design&Simulation of Space Systems K.N.Toosi University of TechnologyTehran891567Iran

The significance of flow optimization utilizing the lattice Boltzmann(LB)method becomes obvious regarding its advantages as a novel flow field solution method compared to the other conventional computational fluid dynamics *** unique characteristics of the LB method form the main idea of its application to optimization *** this research,for the first time,both continuous and discrete adjoint equations were extracted based on the LB method using a general procedure with low implementation *** proposed approach could be performed similarly for any optimization problem with the corresponding cost function and design variables ***,this approach was not limited to flow fields and could be employed for steady as well as unsteady ***,the continuous and discrete adjoint LB equations and the cost function gradient vector were derived mathematically in detail using the continuous and discrete LB equations in space and time,***,new adjoint concepts in lattice space were ***,the analytical evaluation of the adjoint distribution functions and the cost function gradients was carried out.

关键词： Aerodynamic optimization continuous and discrete adjoint approach lattice Boltzmann method

Melatonin and/or rowatinex attenuate streptozotocin-induced diabetic renal injury in rats

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The Journal of Biomedical Research 2019年第2期33卷 113-121页

作者： Tarek k Motawi Samia A Ahmed Manal A hamed Shohda A El-Maraghy Wessam M Aziz Biochemistry Department Faculty of Pharmacy Cairo University Therapeutic Chemistry Department National Research Centre

The study aimed to explore the prophylactic effect of melatonin, rowatinex; a naturally occurring renal drug, and its combination on diabetic nephropathy in type 2 diabetic rats. Diabetes was induced by intraperitoneal injection of a single dose of streptozotocin(50 mg/g body weight). Three days before diabetes induction, rats were daily treated with melatonin, rowatinex and their combination continuously for 8 weeks. Evaluation was done through measuring blood urea nitrogen(BUN), serum uric acid, serum creatinine, urine creatinine, creatinine clearance, nitric oxide(NO), malondialdehyde(MDA), superoxide dismutase(SOD), glutathione(GSH), total antioxidant capacity(TAC),kidney injury molecule-1(kIM-1), heat shock protein-70(HSP-70), caspase-3, transforming growth factor β1(TGFβ1), DNA degradation by the comet assay and total protein contents. Histopathologic study was also done for the kidney and the pancreas. Drastic changes in all measured parameters of the diabetic rats were observed. Treatment with melatonin and rowatinex showed amelioration to variable degrees. In conclusion, melatonin showed the most potent effect on protecting rats from deleterious action of diabetic nephropathy followed by its combination with rowatinex.

关键词： diabetic nephropathy melatonin rowatinex histopathology

Cooling enhancement of planar-balanced magnetron cathode

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Nuclear Science and Techniques 2017年第8期28卷 69-74页

作者： M'hamed Salhi Seddik El Hak Abaidia Brahim Mohamedi Sofiane Laouar Centre de Recherche Nucleaire de Birine B.P. 18017200 Ain-Oussera Algeria Unite de Recherche MPE Faculte des Sciences de l'Ingenieur Universite M'hamed Bougarra de Boumerdes 35000 Boumerdes Algeria

In physical vapor deposition on a magnetron cathode, temperature of sensitive components must be kept under threshold limit, so as to ensure the cathode reliability,the process reproducibility, and the best quality of thin *** can be achieved by an adequate design to enhance the dissipation of heat generated at the cathode. In this paper,temperature distribution and streamlines velocity of the cathode coolant inside a cathode magnetron are analyzed by using CFD solver ANSYS FLUENT in the single-phase method in combination with k–e standards turbulent *** results show that the design is appropriate under the calculation parameters, and for high heat densities some improvements are necessary to enhance heat dissipation and keep temperature under the threshold limit.

关键词：阴极冷却强化磁控平衡平面物理气相沉积 FLUENT 温度分布

Simple physically-based constitutive equations for hot deformation of 2024 and 7075 aluminum alloys

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Transactions of Nonferrous Metals Society of China 2015年第5期25卷 1614-1618页

作者： hamed MIRZADEH School of Metallurgy and Materials Engineering College of EngineeringUniversity of Tehran

The hot working behaviors of 2024 and 7075 aluminum alloys were studied through constitutive analysis based on a physically-based approach which accounts for the dependence of the elastic modulus and the self-diffusion coefficient of aluminum on temperature. It was demonstrated that the lattice self-diffusion activation energy of aluminum（142 k J/mol） can be used in the Zener-Hollomon parameter＇s formula as the deformation activation energy and the theoretical exponent of 5 can be set in the modified hyperbolic sine law to describe the peak flow stresses. By consideration of physically-based material＇s parameters, it was possible to conduct a comparative study on the hot flow stress of 2024 and 7075 aluminum alloys. It was concluded that the used approach in the current work can be considered as a versatile tool in future comparative hot working studies, especially in studies dedicated to alloy development.

关键词： aluminum alloy hot deformation constitutive equation activation energy diffusion

Organic geochemical and petrographic characteristics of the Cambrian-Ordovician organic-rich marine shales in Scandinavia

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Petroleum Science 2023年第5期20卷 2637-2647页

作者： Xiao-Wei Zheng Niels-HSchovsbo Lei-Bo Bian Arka Rudra hamed Sanei Lithospheric Organic Carbon(LOC)Group Department of GeoscienceAarhus University8000Denmark Department of Reservoir Geology Geological Survey of Denmark and Greenland(GEUS)Oster Voldgade 10Dk-1350Copenhagen KDenmark Research Institute of Petroleum Exploration and Development PetroChinaBeijing 100083China

This work used organic geochemistry and organic petrology to study the depositional environment,organic matter characteristics,and thermal maturity of the Cambrian-Ordovician organic-rich marine shales in the Baltic *** main macerals in Cambrian samples include alginite,bituminite and solid bitumen,while zooclastic macerals become the major proportion of organic matter in the Ordovician *** the maturity increase,solid bitumen becomes abundant and ***-like maceral was observed only in Furongian of well DBH15/73,which probably indicates the local intrusion of Permo-Carboniferous dolerite *** programmed pyrolysis results show that immature,early mature,and over-mature samples are ***,the data of high-uranium Furongian samples were greatly altered by igneous intrusives from local *** calculation model is simulated based on pyrolysis data and fitted according to the least-square fitting *** simulated fitting HIo:400mg HC/g TOC(369.5 mg HC/g TOC,430.5 mg HC/g TOC as 95%confidence bounds)is within the worldwide marine shale HI_(o)and indicates a marine anoxia and transgressive sea with shallow water column(organofacies B).

关键词： Lower paleozoic Organic petrology Initial hydrogen index Original geochemical properties

Tramadol Pill Alone May Cause Serotonin Syndrome

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Chinese Medical Journal 2016年第7期129卷 877-878页

作者： hamed Aminiahidashti Sajjad Shaliee Seyed JaberMousavi Gholamhossein Hajiaghaei Department of Emergency Medicine Imam Khomeini Hospital Mazandaran University of Medical Sciences Sari Iran Department of Neurosurgery Imam Khomeini Hospital Mazandaran University of Medical Sciences Sari Iran Department of Community Medicine Imam Khomeini Hospital Mazandaran University of Medical Sciences Sari Iran

To the Editor： Tramadol is a synthetic opioid analgesic chemically related to codeine and is classified as a Class II drug for the treatment of moderate intensity pain according to the WHO recommendation. Tramadol has low affinity for μ- and k-opioid receptors and inhibits the reuptake of both norepinephrine and serotonin （5-hydroxytryptamine） neurotransmitters. It stimulates the dopamine （D2） receptors and also inhibits the gamma amino butyric acid release in central nervous system, Serotonin syndrome （SS） is a potentially life-threatening adverse drug reaction to serotonergic medication.

关键词： Tramadol synthetic chemically