检索结果-南通市图书馆

Journal of Environmental Sciences 2012年第9期24卷 1686-1693页

作者： Amina Chnirheb Mourad Harir Basem Kanawati Mohammed El azzouzi Istvan Gebefgi Philippe Schmitt-Kopplin Department of BioGeoChemistry and Analytik German Research Center for Environmental HealthHelmholtz Center MunichIngoldstdter Landstraβe 1D-85764 NeuherbergGermany University Mohammed V-Agdal Faculty of SciencesAvenue Ibn BatoutaBP 1014 RabatMorocco. Lehrstuhl fr Chemische-Technische Analyse und Chemische Lebensmitteltechnologie Technische Universitt MuenchenWeihenstephaner Steig 2385354 Freising-WeihenstephanGermany

The photodegradation of mefenpyrdiethyl （MFD）, an herbicide safener, was investigated in aqueous suspensions by using Degussa P-25 and Hombikat UV100 titanium oxide under simulated sunlight irradiation. The effects of initial concentration of the herbicide, pH, catalysts and hydrogen peroxide doses as well as their combinations were studied and optimized. Accordingly, the kinetic parameters were determined and the effectiveness of the processes was assessed by calculating the rate constants. A pseudo first-order kinetics was observed. Under experimental conditions, the degradation rate constants were strongly influenced using P-25 and no noticeable effect was observed for Hombikat UV100. DFT calculations with B3LYP/6-311＋G（2d,p）//B3LYP/6-31＋G（d,p） level of theory were performed to check whether significant conformational changes occur when the charge state of the MFD substrate changes and whether these changes could play a role in the dependency of photodegradation rate constant on the studied pH. High resolution mass spectrometry （FT-ICR/MS） was implemented to identify the main degradation products.

关键词： photodegradation mefenpyrdiethyl P-25/Hombikat UV100 kinetic degradation products

Upgrading of Industrial Wastewater Treatment Units at Automobile Industry

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2000年第3期13卷 219-224页

作者： abdel Wahaab R Water Pollution Research Department National Research CenterCairoEgypt

Industrial wastewater is one of the major sources of water pollution in *** principal hazard to public health caused by industrial wastes is pollution with toxic materials,which may enter a municipal water supply or may be harmful to people using the stream for recreatinal *** wastes can damage aquatic life,sewer fabric and interfere with the operation of treatment ***,persistent untreated pollutats passing through these systems may contaminate receving water bodies and incresae the cost and environmental risks of sludge treatment and disposal.

关键词： Upgrading of Industrial Wastewater Treatment Units at Automobile Industry

An application of a simple computer program for neutron activation analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2001年第1期13卷 22-24页

作者： N.abdel Basset Nuclear Physics Laboratory Ain Shams UniversityFaculty of Girs-HeliopolisCairoEgypt

A simple computer program is designed for estimation of elemental concentration values in complex samples by neutron activation analysis technique. The program is applied for an Egyptian cement sample which irradiated at the Egyptian Research Reactor 1(ET RR 1). The data obtained is compared with the reported values. The time consumed for such calculations has a remarkable reduction in comparison with the routine work.

关键词： neutron activation analysis cement sample Egypt

Self-phase modulation via similariton solutions of the perturbed NLSE Modulation instability and induced self-steepening

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2022年第8期74卷 41-50页

作者： H I abdel-Gawad Department of Mathematics Faculty of Science Cairo University Egypt

The perturbed nonlinear Schrodinger equation(PNLSE)describes the pulse propagation in optical fibers,which results from the interaction of the higher-order dispersion effect,self-steepening(SS)and self-phase modulation(SPM).The challenge between these aforementioned phenomena may lead to a dominant one among *** is worth noticing that the study of modulation instability(MI)leads to the inspection of dominant phenomena(DPh).Indeed,the MI triggers when the coefficient of DPh exceeds a critical value and it may occur that the interaction leads to wave *** PNLSE is currently studied in the literature,mainly on finding traveling wave ***,we are concerned with analyzing the similarity solutions of the *** exact solutions are obtained via introducing similarity transformations and by using the extended unified *** solutions are evaluated numerically and they are shown *** is observed that the intensity of the pulses exhibits self steepening which progresses to shock soliton in ultrashort time(or near t=0).Also,it is found that the real part of the solution exhibits self-phase modulation in *** study of(MI)determines the critical value for the coefficients of SS,SPM,or high dispersivity to occur.

关键词： Perturbed NLSE steepening self–phase modulation extended unified method

The effect of atomic spontaneous decay on the dynamics of the negativity of the Wigner function of radiation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2011年第9期20卷 44-48页

作者： abdel-Baset A.Mohamed Faculty of Science Assiut UniversityAssiutEgypt

The exact solution of the master equation for the case of a high-Q cavity with atomic decay is found. We use the negativity of the Wigner function （WF） as an indicator of nonclassicality. It is found that the negative values of the field WF are very sensitive to any change in the damping parameter. The atomic spontaneous decay leads to the simultaneous disappearance of both entanglement and nonclassicality of quantum states. Moreover, the purity of the field states is completely lost.

关键词： non-classicality entanglement atomic decay

Seismic response of skewed RC box-girder bridges

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2008年第4期7卷 415-426页

作者： Ahmed abdel-Mohti Gokhan Pekcan Civil and Environmental Engineering Department University of Nevada Reno

It is critical to ensure the functionality of highway bridges after earthquakes to provide access to important facilities. Since the 1971 San Fernando earthquake, there has been a better understanding of the seismic performance of bridges. Nonetheless, there are no detailed guidelines addressing the performance of skewed highway bridges. Several parameters affect the response of skewed highway bridges under both service and seismic loads which makes their behavior complex. Therefore, there is a need for more research to study the effect of skew angle and other related factors on the performance of highway bridges. This paper examines the seismic performance of a three-span continuous concrete box girder bridge with skew angles from 0 to 60 degrees, analytically. Finite element （FE） and simplified beam-stick （BS） models of the bridge were developed using SAP2000. Different types of analysis were considered on both models such as： nonlinear static pushover, and linear and nonlinear time history analyses. A comparison was conducted between FE and BS, different skew angles, abutment support conditions, and time history and pushover analysis. It is shown that the BS model has the capability to capture the coupling due to skew and the significant modes for moderate skew angles. Boundary conditions and pushover load profile are determined to have a major effect on pushover analysis. Pushover analysis may be used to predict the maximum deformation and hinge formation adequately.

关键词： skew bridge seismic response pushover analysis time history analysis modeling

A poroelastic numerical model for simulation of hydraulic fracture propagation:Application to Upper Safa formation-Western Desert-Egypt

在线全文

学校读者我要写书评

暂无评论

Petroleum Research 2020年第1期5卷 39-51页

作者： Reda abdel Azim Petroleum Engineering Department American University of KurdistanDohoukIraq

The hydraulic fracturing in tight sand formations has a significant importance in improving its production *** this study,a poroelastic numerical model is presented in order to study the reservoirs and rock mechanical properties that affect the propagation of the hydraulic *** poroelastic model simulate fully coupled fluid flow,pressures and stress changes by using finite element *** results show that the formation permeability and fracture toughness are key parameters in the design of hydraulic fracture treatment.A case study applied in Upper Safa formation in a well-located western desert *** formation is very tight with permeability of 0.1md and the objective here is to optimize the design procedures for hydraulic fracture *** results show that the formation needs to be pumped for about 5min to produce hydraulic fracture length of 182 *** addition,the total pumping time(30 min)is vital to produce the desired total fracture length of 1000 ft.

关键词： Fracture propagation Finite element Upper Safa formation Poroelastic Leak off model

Particle size effect on ammonium perchlorate decomposition kinetics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

航空动力学报 2012年第5期27卷 1179-1184页

作者： abdel-Wareth W XU Xu School of Astronautics Beijing University of Aeronautics and AstonauticeBeijing 100191China

The decomposition kinetic parameters of ammonium perchlorate(AP) having different grain size(10-390 μ m) were investigated through simultaneous DSC / TGA(differential scanning calorimetry / thermal gravimetric analysis) analyzer in a dynamic nitrogen atmosphere under heating rate of 40K / *** kinetic parameters such as activation energy and pre-exponential factor were determined by the modified isoconversional *** Brurzauer-Emmett-Teller(BET)-method was applied to measure AP specific surface *** results show that the higher the AP particle size the lower the determined kinetic parameters and are matched with some important literatures.

关键词： ammonium perchlorate particle size specific surface area thermal decomposition thermogravimetry

Impact of wastewater reuse on cobalt status in Egyptian environment

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2003年第3期15卷 388-395页

作者： M.F. abdel-Sabour Soil and Water Research Department Nuclear Research Center Atomic Energy Authority

Cobalt is used in the manufacture of alloys, catalysts in the petroleum industry, catalytic converters, and paint pigments. Thus the potential for Co releases into the environment is highly increased. Use of waste sludges and sewage effluent to fertilize and irrigate soils has also increased soil Co concentrations. Total cobalt contents of alluvial delta soil of Egypt show considerable variation ranging from 13.1 to 64.7 ppm. The impact of either wastewater irrigation or industrial activities on soil total Co was obvious due to accumulation of organic matter and solid waste in the surface soil samples. Food crops and vegetables should not be grown on soil highly contaminated by Co. It is noteworthy that the delayed neutron activation analysis(DNAA) technique could be used successfully for total Co determination due to its high sensitivity. It is quit clearly that dust samples of Cairo City contains higher Co level, as compared to Suez Canal Region(Ismailia, Port Said and El-Suez cities). The high values in Cairo City may be due to the existence of industries around the city and the intensive traffic. To minimize Co environmental hazards, waste effluents should be treated on site. Thus, levels of potentially toxic Co needs to be continuously monitored and should be removed during several treatment processes before the disposal of these wastes.

关键词： cobalt environment Egypt

A hybrid simulation approach to evaluate stimulation micro-seismic events and production potential of fractured geothermal reservoirs

在线全文

学校读者我要写书评

暂无评论

Petroleum Research 2020年第2期5卷 131-143页

作者： Reda abdel Azim Petroleum Engineering Department American University of Kurdistan Zakho Rd.99641DohoukIraq

This study presents an integrated approach to simulate fluid flow and to predict the micro seismic eventsduring stimulation and circulation of cold water over a longer term in geothermal reservoirs. The integrated approach based on new three dimensional fully coupled thermo-poroelastic numerical model forevaluation of energy recoverable. In the presented approach, the fracture aperture due to fractureslippage is calculated by shear and dilation. The shear slippage is controlled by the concept of shearfailure using linear Mohr-Coulomb criterion. The numerical model is validated against an analytical Oda’smodel for permeability tensor calculation and against an analytical solution for thermo-poroelasticmodel. The heat transfer between the rock and fluid is modelled by using the conductive heat transferwithin the reservoir rock and convective heat transfer in discrete fractures. The thermal stress changesare included in the model to be studied by using roughness induced shear displacement principle in aporo-thermo-elastic environment. The fracture aperture changes are estimated by using an analyticalmodel based on the distributed dislocation technique. The roughness of fracture surfaces is used in thecalculation of residual fracture aperture. The presented approach is used to study the potential ofpermeability enhancement for Habanero geothermal reservoir at a depth of 3600 m. The result show thatthe increasing in tensile effective stress tend to increase the fracture aperture within the zone of *** increasing in fracture aperture led to significant changes in pressure distribution (decrease inimpedance) and hence, increase in the flow rate.

关键词： Fractured reservoirs Finite element Permeability tensor Fracture aperture Tensile stress Fractal density and dimension