OALib Journal期刊

ISSN: 2333-9721




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匹配条件: “A Ghasempoor” ,找到相关结果约460542条。
Multiplicity distribution of charged particles in e+ e– annihilation in 54-57 GeV centre of mass energy and KNO scaling
A Ghasempoor Nashli,A Sepehri,T Gaffary,ME Zomorrodian
Iranian Journal of Physics Research , 2009,
Abstract: In this paper, we investigate the multiplicity of charged particles in e+ e– annihilation by using different models. To achieve this we first fit the multiplicity distribution of charged particles in the energy range of 54-57 GeV by using both the Poisson distribution and KNO scaling, then we compare these results with multiplicity distribution at the lower energies. This comparison shows that our results are more compatible with KNO scaling in this energy range. Also we fit the multiplicity distribution of our data, together with the other data up to 206 GeV, to Fermi model, the pp data model and the model obtained from perturbative QCD. The coefficients obtained by these methods are consistent with those obtained at lower energies.
Comparing Carotid Intima-Media Thickness In Type 2 Diabetes Between Patients With And Without Retinopathy
M Naroi Nejad,M Yousefi,H Nazari,A Ghasempoor
Tehran University Medical Journal , 2012,
Abstract: Background: Microangiopathy and macroangiopathy frequently coexist in type 2 diabetes mellitus (T2DM). Both types of the vascular complications share traditional risk factors but it is not clear whether the presence of microangiopathy, such as diabetic retinopathy, constitutes a predictor of atherosclerosis in carotid arteries in patients with the disease. In this study we looked for the association between diabetic retinopathy and intima-media thickness in carotid arteries of patients with T2DM. Methods: In this case-control study we examined 100 consecutive patients with T2DM in Rasoul Akram Hospital in Tehran, Iran during 2009-2010. We assessed intima-media thickness of carotid arteries by ultrasonography. All patients underwent ophthalmo-logic examination. Results: Diabetic retinopathy was found in 50 (50%) patients. Intima-media thickness was higher in patients with diabetic retinopathy than those without it (0.77±0.17 mm vs. 0.71±0.2 mm, respectively, P=0.041). Moreover, intima-media thickness was more prevalent in patients with proliferative diabetic retinopathy than patients with non-proliferative form of the disease (0.87±0.16 mm vs. 0.68±0.1 mm, respectively, P<0.001). Conclusion: Diabetic retinopathy seems to be associated with increased intima-media thickness of carotid arteries in T2DM. It may be a common denominator of pathogene-sis of microvascular complications and atherosclerosis in T2DM. Evaluations of carotid arteries are to be done by non-invasive methods such as color Doppler sonography for screening and preventing prospective cereberovascular accidents in patients with diabetic retinopathy, especially proliferative retinopathy, in routine ophthalmological examination of patients with T2DM.
Active Vibration Suppression Using Neural Networks
Yong Xia,Ahmad Ghasempoor
Lecture Notes in Engineering and Computer Science , 2009,
A survivability model for ejection of green compacts in powder metallurgy technology
Payman Ahi,Kouroush Jenab,Ahmad Ghasempoor
International Journal of Industrial Engineering Computations , 2012,
Abstract: Reliability and quality assurance have become major considerations in the design and manufacture of today’s parts and products. Survivability of green compact using powder metallurgy technology is considered as one of the major quality attributes in manufacturing systems today. During powder metallurgy (PM) production, the compaction conditions and behavior of the metal powder dictate the stress and density distribution in the green compact prior to sintering. These parameters greatly influence the mechanical properties and overall strength of the final component. In order to improve these properties, higher compaction pressures are usually employed, which make unloading and ejection of green compacts more challenging, especially for the powder-compacted parts with relatively complicated shapes. This study looked at a mathematical survivability model concerning green compact characteristics in PM technology and the stress-strength failure model in reliability engineering. This model depicts the relationship between mechanical loads (stress) during ejection, experimentally determined green strength and survivability of green compact. The resulting survivability is the probability that a green compact survives during and after ejection. This survivability model can be used as an efficient tool for selecting the appropriate parameters for the process planning stage in PM technology. A case study is presented here in order to demonstrate the application of the proposed survivability model.
The Internationalization of Higher Education: An Effective Approach for Iran Higher Education
Ali Ghasempoor,Mohmmd Javad Liaghatdar,Ebrahim Jafari
Higher Education Studies , 2011, DOI: 10.5539/hes.v1n2p35
Abstract: In recent years, the subject of internationalization has been one of the most discussed issues in academic and university centers. Experts in the higher education believe that this subject is a new paradigm and inevitable approach in the universities and curriculum. Internationalization refers to the process of integrating an international and intercultural dimension into the teaching, research and service functions of the institution. It is a term that is being used more and more to discuss the international dimension of higher education. It is a term that means different things to different people and is thus used in a variety of ways. The purpose of this study is, surveying the nature of internationalization of higher education and its causality, practical models and specifying it holistically for stakeholders of higher education systems.
A Comparative Investigation of Lead Sulfate and Lead Oxide Sulfate Study of Morphology and Thermal Decomposition  [PDF]
S. A. A. Sajadi
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.22024
Abstract: The compound lead oxide sulfate PbSO4.PbO was prepared in our laboratory. The Thermal behavior of PbSO4 was studied using techniques of Thermogravimetry under air atmosphere from 25 to 1200°C. The identity of both compounds was confirmed by XRD technique. Results obtained using both techniques support same decomposition stages for this compound. The electron microscopic investigations are made by SEM and TEM. The compound is characterized by XRD and the purity was determined by analytical Methods. Also a series of thermogravimetric analysis is made and the ideal condition is determined to convert this compound to pure lead oxide.
Metal ion-binding properties of L-glutamic acid and L-aspartic acid, a comparative investigation  [PDF]
S. A. A. Sajadi
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.22013
Abstract: A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.
Determining the Basaltic Sequence Using Seismic Reflection and Resistivity Methods  [PDF]
A. Alanezi, A. Qadrouh
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.32B004

This study was carried out in Harat Rahat (south of Almadinah Almonwarah) using seismic reflection and resistivity methods. The main objectives of this study are to determine the extent of the basaltic layer and to define the subsurface faults and fractures that could affect and control the groundwater movement in the study area. A 2D seismic profile was acquired and the result shows that the subsurface in the study area has a major fault. We obtained a well match when the seismic result was compared with drilled wells. As a complementary tool, the resistivity method was applied in order to detect the groundwater level. The results of the resistivity method showed that six distinct layers have been identified. The interpretation of these six layers show that the first three layers, the fourth layer, the fifth layer and the bottom of the section indicated various subsurface structures and lithologies; various basaltic layers, fractured basalt, weathered basement and fresh basaltic layers, respectively. It is obvious that the eventual success of geophysical surveys depend on the combination with other subsurface data sources in order to produce accurate maps.

Equilibria and Stability in Glycine, Tartrate and Tryptophan Complexes, Investigation on Interactions in Cu(II) Binary and Ternary Systems in Aqueous Solution  [PDF]
S. A. A. Sajadi
Open Journal of Inorganic Non-metallic Materials (OJINM) , 2014, DOI: 10.4236/ojinm.2014.41001

The acidity and stability constants of M(Gly)1, M(Ttr)1, and M(Trp)1 M: Cu2+, Cu(Bpy2)2+, and Cu(Phen3)2+ complexes, were determined by potentiometric pH titration. It is shown that the stability of the binary Cu(L), (L: Gly, Ttr, and Trp) complex is determined by the basicity of the carboxylate group on one side and amino group on the other side. It is demonstrated that the equilibrium, Cu(Ha4)2+ + Cu(L) \"\"Cu(Har)(L) + Cu2+, is displacement due to the well known experience that mixed ligand complexes formed by a divalent 3d ion, a heteroaromatic N base and an O donor ligand possess increased stability. The stability constants of the 1:1 complexes formed between Cu2+, Cu(Bpy)2+ or Cu(Phen)2+

Adaptive Fuzzy Sliding Mode Controller for Grid Interface Ocean Wave Energy Conversion  [PDF]
Adel A. A. Elgammal
Journal of Intelligent Learning Systems and Applications (JILSA) , 2014, DOI: 10.4236/jilsa.2014.62006

This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.


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