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Journal of Central South University 2016年第9期23卷 2254-2267页

作者： Abdolkhalegh Hamidi Jamal Beiza ebrahim Babaei Sohrab Khanmohammadi Departement of Electrical Engineering Shabestar Branch Islamic Azad University

An input-output signal selection based on Phillips-Heffron model of a parallel high voltage alternative current/high voltage direct current(HVAC/HVDC) power system is presented to study power system stability. It is well known that appropriate coupling of inputs-outputs signals in the multivariable HVDC-HVAC system can improve the performance of designed supplemetary controller. In this work, different analysis techniques are used to measure controllability and observability of electromechanical oscillation mode. Also inputs–outputs interactions are considered and suggestions are drawn to select the best signal pair through the system inputs-outputs. In addition, a supplementary online adaptive controller for nonlinear HVDC to damp low frequency oscillations in a weakly connected system is proposed. The results obtained using MATLAB software show that the best output-input for damping controller design is rotor speed deviation as out put and phase angle of rectifier as in put. Also response of system equipped with adaptive damping controller based on HVDC system has appropriate performance when it is faced with faults and disturbance.

关键词： input-output signal selection online adaptive damping controller nonlinear high voltage direct current power systemstability

A Novel Modeling, Simulation and Optimization Approach of Crude Oil Cold Stripping Process

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China Petroleum Processing & Petrochemical Technology 2013年第1期15卷 78-84页

作者： Kaveh Hezaveh Hesarmaskan HabibAle ebrahim Amirkabir University of Technology (Tehran Polytechnic) Department of Chemical Engineering

Cold stripping is the most common process for crude oil sweetening in oilfields particularly at offshore installations because of its low price and relatively easy operating conditions in comparison with other sweetening processes. In this paper the cold stripping process in tray column has been modeled mathematically in static and dynamic modes, and solved with the MATLAB software. This process has been used in the existing treatment facilities of an offshore oil production complex for verifying the model results. With the help of HYSYS software the effective parameters on the process have been discussed and the optimized conditions finalized after some plant modifications for improving the performance of stripper columns have been proposed.

关键词： modeling simulation optimization sour crude oil cold stripping

An accurate empirical correlation for predicting natural gas viscosity

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Journal of Natural Gas Chemistry 2011年第6期20卷 654-658页

作者： Ehsan Sanjari ebrahim Nemati Lay Mohammad Peymani Department of Chemical Engineering Faculty of EngineeringUniversity of Kashan

Natural gas viscosity is an important parameter in many gas and petroleum engineering *** study presents a new empirical model for quickly calculating the natural gas *** model was derived from 4089 experimental viscosity data with varieties ranging from 0.01 to 21,and 1 to 3 of pseudo reduced pressure and temperature,*** accuracy of this new empirical correlation has been compared with commonly used empirical models,including Lee et al.,Heidaryan et al.,Carr et al.,and Adel Elsharkawy *** comparison indicates that this new empirical model can predict viscosity of natural gas with average absolute relative deviation percentage AARD （%） of 2.173.

关键词： viscosity natural gas correlation empirical model

Preliminary rib support requirements for solid coal ribs using a coal pillar rib rating(CPRR)

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International Journal of Mining Science and Technology 2021年第1期31卷 15-22页

作者： Khaled Mohamed Mark Van Dyke Gamal rashed Morgan MSears Robert Kimutis National Institute for Occupational Safety and Health Pittsburgh Mining Research DivisionPittsburghPA 15236USA

Researchers from the National Institute for Occupational Safety and Health(NIOSH)are developing a coal pillar rib rating(CPRR)technique to measure the integrity of coal *** CPRR characterizes the rib composition and evaluates its impact on the inherent stability of the coal *** CPRR utilizes four parameters:rib homogeneity,bedding condition,face cleat orientation with respect to entry direction,and rib *** these parameters are measurable in the field.A rib data collecting procedure and a simple sheet to calculate the CPRR were *** developed CPRR can be used as a rib quality mapping tool in underground coal mines and to determine the potential of local rib instabilities and support requirements associated with overburden *** calculations were conducted for 22 surveyed solid coal ribs,mainly composed of coal *** on this study,the rib performance was classified into four categories.A preliminary minimum primary rib support density(PRSD)line was obtained from these surveyed *** sample cases are presented that illustrate the data collection form and CPRR calculations.

关键词： Coal rib stability Rib support design Coal pillar rib rating Rib quality mapping CPRR Coal classification

Enhancing Energy Utilization Efficiency of Pakistani System Considering FACTS Devices and Distributed Generation:Feasibility Study

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Chinese Journal of Electrical Engineering 2020年第2期6卷 66-82页

作者： Ghamgeen Izat rashed Hussain Haider M.B.Shafik School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China

In recent years,voltage stability issues have become a serious concern with regard to the safety of electrical systems,these issues are more evident and have wider consequences in vertical networks with an insufficient reactive power *** is currently suffering from the worst energy crisis in its *** to an increase in energy demand,the current transmission system is becoming increasingly *** has thus become necessary to reduce losses and enhance the system voltage profile for more efficient energy *** this study,the main emphasis is on assessing the feasibility of using flexible AC transmission system devices and distributed generation to compensate power failures on the power lines of the Pakistani power transmission *** load flow and contingency analyses are performed on a 132 kV transmission system that feeds power to the Quetta electric supply *** region of Baluchistan is studied to evaluate the effectiveness of the proposed *** system is simulated using NEPLAN,which accurately models the details of all system elements and the optimal power *** simulation results indicate that the proposed method helps reduce system losses,voltage deviation,and power flow congestion,with all system constraints within permissible limits.

关键词： Pakistani power system FACTS devices distributed generation power losses voltage deviation

Change of the mode of failure by interface friction and width-to-height ratio of coal specimens

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第3期7卷 256-265页

作者： Gamal rashed Syd S.Peng Department of Mining Engineering West Virginia University

Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine *** studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height（W/H） ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.

关键词： Bump Burst Coal strength Violent failure Width-to-height(W/H) ratio Interface friction Stressestrain curve

Assessment of radioactivity levels in some oil samples from the western desert,Egypt

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Nuclear Science and Techniques 2007年第2期18卷 118-122页

作者： A. ABBADY A.M. EL-ARABI W. rashed Physics Department Faculty of Science South Valley University Qena Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.

关键词：埃及西部沙漠地区油料样品放射性评估

Effect of salts and their interaction with ingenious surfactants on the interfacial tension of crude oil/ionic solution

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Chinese Journal of Chemical Engineering 2020年第1期28卷 224-235页

作者： Mostafa Lashkarbolooki Roohollah Parvizi Shahab Ayatollahi ebrahim Ghaseminejad Raeeni School of Chemical Engineering Babol Noshirvani University of TechnologyBabolIran Department of Chemical Engineering Islamic Azad UniversityIran School of Chemical and Petroleum Engineering Sharif University of TechnologyTehranIran National Iranian South Oil Company Iran

Understanding the roles of asphaltene and resin as natural surfactants existed in crude oil can enlighten contradicting reported results regarding interfacial tension(IFT) of crude oil/aqueous solution as a function of salinity and ion type. In this way, this study is aimed to investigate the effect of these natural surface active agents on IFT of with special focus on SO4^2-anion and Mg^2+cation. Two different synthetic oil solutions of 8 wt% of the extracted asphaltene and resin dissolved in toluene are prepared, and then IFT values are measured. After that,the obtained results are compared with the IFT of intact crude oil in contact with the same saline solutions examined in the previous stage. The obtained results showed a synergistic effect of Na2SO4+ MgCl2 solution unlike the MgSO4+ MgCl2 and CaSO4+ MgCl2 solutions on IFT reduction of resin at MgCl2 concentration of 15000 mg·kg^-1. In summary, it is found that the affinity of asphaltene molecules towards the interface of oleic phase/ionic solution leads to higher IFT variation.

关键词： IFT Resin Asphaltene Mg^2+ SO4^2-

Silica-bonded N-propylsulfamic acid as a recyclable catalyst for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones

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Chinese Chemical Letters 2011年第1期22卷 69-72页

作者： Khodabakhsh Niknam Nasrolah Jafarpour ebrahim Niknam Department of Chemistry Islamic Azad UniversityGachsaran BranchGachsaranIran

2,3-Dihydroquinazolin-4（1H）-one derivatives are synthesized via a one-pot, three component reaction of isatoic anhydride and an aromatic aldehyde with ammonium acetate or primary amine catalyzed by silica-bonded N-p... 详细信息

关键词： Silica-bonded N-propylsulfamic acid 2,3-Dihydroquinazolin-4(1H)-ones Isatoic anhydride Aldehydes

SARS-CoV-2 getting into the brain;neurological phenotype of COVID-19,and management by nano-biotechnology

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Neural Regeneration Research 2023年第3期18卷 519-520页

作者： Małgorzata Kujawska ebrahim Mostafavi Ajeet Kaushik Department of Toxicology Poznan University of Medical SciencesPoznańPoland Stanford Cardiovascular Institute/Department of Medicine Stanford University School of MedicineStanfordCAUSA NanoBioTech Laboratory Health Systems EngineeringDepartment of Natural SciencesFlorida Polytechnic UniversityLakelandFLUSA

Human coronavirus infection getting into the brain:By February 2022,the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection,causing the coronavirus disease 2019(COVID-19)outbreak,has infected around 415 million people,and caused~5.8 million deaths worldwide(WHO,https://***/).As SARS-CoV-2 replicates during the infection,it undergoes genetic mutation to generate variants with varying characteristics and mutation *** emerging,over time,new variants that differ with transmissibility,immunity,and infection severity pose continuous challenges to established COVID-19 management strategies and *** SARS-CoV-2 variants such as Omicron(B.1.1.529),Delta(B.1.617.2),UK(B.1.17),South Africa(B.1.351),Brazil(P.1),and New York B.1.525-B.1.526 were detected worldwide and accelerated severity of COVID-19 pandemic(Figure 1A;McQuaid et al.,2021).

关键词： immunity Figure getting