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Chinese Physics B 2021年第5期30卷 507-512页

作者： Meryem Grari CifAllah Zoheir yasser Yousfi Abdelhak Benbrik University mohamed First Department of PhysicsLETSER LaboratoryOujdaMorocco University mohamed First Department of MathematicsLANO LaboratoryOujdaMorocco

The fluid model,also called the macroscopic model,is commonly used to simulate low temperature and low pressure radiofrequency plasma *** varying the parameters of the model,numerical simulation allows us to study several cases,providing us the physico-chemical information that is often difficult to obtain *** this work,using the fluid model,we employ numerical simulation to show the effect of pressure and space between the reactor electrodes on the fundamental properties of silicon plasma diluted with ammonia and *** results show the evolution of the fundamental characteristics of the plasma discharge as a function of the variation of the pressure and the distance between the *** examining the pressure-distance product in a range between 0.3 Torr 2.7 cm and 0.7 Torr 4 cm,we have determined the optimal pressure-distance product that allows better deposition of hydrogenated silicon nitride(SiN_(x)H_(y))films which is 0.7 Torr 2.7 cm.

关键词： fluid model numerical simulation SiN_(x)H_(y) capacitively coupled plasma reactor

Proposed Method for Cost Assessment of Seismic Mitigation Designs for Reinforced Concrete Buildings According to ECP Code

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Open Journal of Civil Engineering 2019年第4期9卷 319-355页

作者： yasser Fayed mohamed E. Sobaih yasser El Hakem Civil Engineering Department Giza engineering Institute GEI Giza Egypt Civil Engineering Department Faculty of Engineering Cairo University Giza Egypt Construction Research Institute National Water Research Center Cairo Egypt

The Earthquake can be considered as a natural phenomenon or a disaster based on the seismic response of structures during a severe earthquake that plays a vital role in the extent of structural damage and resulting injuries and losses. It is necessary to predict the performance of the existing structures and structures at the design stage when it subjected to an earthquake load. Also, it is needed to predict the repair cost required for the rehabilitation of the existing buildings that is insufficient in seismic resistance, and the construction cost and the expected repairing cost for the structures at the design stage that designed to have a ductile behavior with acceptable cracks. This study aims to propose a method for seismic performance evaluation for existing and new structures depending on the width of cracks resulted from the seismic exposure. Also, it assesses the effect of building performance during earthquakes on its life cycle cost. FEMA 356 criteria were used to predict the building responses due to seismic hazard. A case study of seven-story reinforced concrete building designed by four design approaches and then analyzed by static nonlinear pushover analysis to predict its response and performance during earthquake events using Sap 2000 software. The first design approach is to design the building to resist gravity loads only by using ECP code. The second one is to design the building to resist gravity loads and seismic loads by using static linear analysis according to ECP code. The third one is to design the building to resist gravity loads and seismic loads by using static linear analysis according to the regulations of the Egyptian Society of Earthquake Engineering (ESEE). Finally the fourth one is to design the building as the second approach but with ground acceleration greater by five times than it or by using ductility factor R = 1. The methodology followed in this study provides initial guidelines, and steps required to assess the seismic pe

关键词： Performance Based Analysis Pushover Analysis Cost Assessment Crack Width

Effects of Building Configuration on Seismic Performance of RC Buildings by Pushover Analysis

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Open Journal of Civil Engineering 2015年第2期5卷 203-213页

作者： yasser Alashker Sohaib Nazar mohamed Ismaiel Structural Engineering Department College of Engineering Zagazig University Zagazig Egypt College of Engineering King Khalid University Abha Kingdom of Saudi Arabia Cairo University Cairo Egypt

In the recent earthquakes, concrete structures have been severely damaged or collapsed, which has raised questions against the seismic adequacy of existing buildings. These existing reinforced concrete buildings need to be evaluated to determine the capacity to resist seismic loads. The behavior of a building during earthquakes depends critically on its overall shape, size and geometry. Conventional approach to earthquake resistant design of buildings depends upon providing the building with strength, stiffness and inelastic deformation capacity which are great enough to withstand a given level of earthquake-generated force. This is generally accomplished through the selection of an appropriate building configuration and the careful detailing of structural members. In this research, nonlinear pushover analysis has been used to evaluate the seismic performance of three buildings with three different plans having same area and height. This method determines the base shear capacity of the building and performance level of each part of building under varying intensity of seismic force. The results of effects of different plan on seismic response of buildings have been presented in terms of displacement, base shear and plastic hinge pattern.

关键词： Pushover Analysis Seismic Performance Base Shear Building Configuration

Influence of Nano-Barium Sulfate Agglomeration on Microstructure and Properties of the Hardened Cement-Based Materials

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Journal of Materials Science and Chemical Engineering 2015年第11期3卷 72-81页

作者： mohamed El-Shahate Ismaiel Saraya Inas Mostafa bakr Department of Chemistry Faculty of Science Al-Azhar University Cairo Egypt Faculty of Engineering Mattareya Helwan University Cairo Egypt

The aim of the present work is to study the effect of Nano-barium sulfate additions on the physic-mechanical properties of hardened cement pastes. Nano-barium sulfate was prepared by the precipitation method. Eight mixes of filled cement pastes containing 0.5 wt%, 1.0 wt%, 1.5 wt% and 2.0 wt% of both nano-barium sulfate and micro-limestone were prepared and compared to the base OPC. The hydration characteristics were evaluated by the measure of combined water content, bulk density, total porosity and compressive strength for samples hydrated up to 90 days. The progress of hydration reactions was followed up by XRD analysis. The morphology and microstructure were studied by SEM. Nano-size barium sulfate acted as a nucleating agent and enhanced the hydration of cement pastes up to 2.0% mass content. Also, the microstructure was improved considerably. Accordingly, nano-size barium sulfate can be used successfully in the preparation of filled cement.

关键词： Nano-Barium Sulfate Cement Paste Filler Compressive Strength Microstructure

Biosynthesis of raw starch degradingβ-cyclodextrin glycosyltransferase by immobilized cells of Bacillus licheniformis using potato wastewater

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BIOCELL 2021年第6期45卷 1661-1672页

作者： yasser S.MOSTAFA SAAD A.ALAMRI SULIMAN A.ALRUMMAN TAREK H.TAHA mohamed HASHEM MAHMOUD MOUSTAFA LAMIAA I.FAHMY Department of Biology College of ScienceKing Khalid UniversityAbha9004Saudi Arabia Prince Sultan Bin Abdulaziz Center for Environmental and Tourism Research and Studies King Khalid UniversityAbha9004Saudi Arabia Environmental Biotechnology Department Genetic Engineering and Biotechnology Research InstituteCity of Scientific Research&Technological ApplicationsNew Borg El-Arab City21934Egypt Department of Botany and Microbiology Faculty of ScienceAssiut UniversityAssiut71515Egypt Department of Botany and Microbiology Faculty of ScienceSouth Valley UniversityQena83523Egypt Department of Microbiology and Immunology Faculty of PharmacyOctober University for Modern Science and ArtGiza12451Egypta

The study was sought to enhance the synthesis of thermal stableβ-cyclodextrin glycosyltransferase(β-CGTase)using potato wastewater as a low-cost medium and assess the degree to which it is efficient for industrial production ofβ-cyclodextrin(β-CD)from raw potato *** bacteria producingβ-CGTase was isolated from Saudi Arabia and the promising strain was identified as Bacillus licheniformis using phylogenetic analysis of the 16S rRNA ***-encapsulated cultures exhibited twice-fold ofβ-CGTase production more than free *** electron microscopy(SEM)of polymeric capsules indicated the potential for a longer shelf-life,which promotes the restoration of activity in bacterial cells across semi-continuous fermentation ofβ-CGTase production for 252 *** optimal conditions forβ-CGTase synthesis using potato wastewater medium were at 36 h,pH of 8.0,and 50°C with 0.4%potato starch and 0.6%yeast extract as carbon and nitrogen sources,*** purified enzyme showed a specific activity of 63.90 U/mg with a molecular weight of∼84.6 kDa as determined by SDS-PAGE *** high enzyme activity was observed up to 60°C,and complete stability was achieved at 75°*** levels of activity and stability were shown at pH 8.0,and the pH range from 7.0–10.0,*** enzyme has an appreciable affinity for raw potato starch with a Km of 5.7×10−6 M and a Vmax of 87.71μmoL/mL/min.β-CD production was effective against 25 U/g of raw potato *** outcomes demonstrated its feasibility to develop a fermentation process by integrating the cost-effective production ofβ-CGTase having distinctive properties forβ-CD production with ecofriendly utilization of potato wastewater.

关键词： Potato wastewater Bacillus licheniformis β-CGTase 16S rDNA gene Semi-continuous fermentation β-cyclodextrin

Particle Size Distribution and Hydraulic Conductivity in Coastal Non-Agricultural Land in Gaza Coastal Plain

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International Journal of Geosciences 2018年第10期9卷 619-633页

作者： Jamal Safi yasser El-Nahhal mohamed Safi Environmental Protection and Research Institute (EPRI) Gaza Palestine Al-Azhar University Gaza Palestine TheIslamic University of Gaza Gaza Palestine

Background: Particle size distribution and hydraulic conductivity of coastal no-agricultural lands are not available. This study characterized the particle size distribution and hydraulic conductivity on coastal non-agricultural land along the coastal plain of Gaza. Materials and Methods: Six soil profiles were digged along the coastal plain in Gaza Strip and soil samples were collected from 0 - 150 cm depth. Four soil plots around each site were used to determine the hydraulic conductivity using Infiltrometer method. Four particle size groups were identified, group 1 (630 nm), group 2 (200 nm), group 3 (63 nm) and group 4 (20 nm). Results: Dominancy of particle size group 2 was noticed in all sites followed by group 3. Groups 1 and 4 were less dominant in all sites. Hydraulic conductivity ranged from lower value 0.27 in the control soil plot in Khan Younis (site 1) to the highest value 1.76 m/s in disturbed soil plot in Shakhejjlen (site 3) with regression coefficient (R2) range of 0.9725 - 0.997 indicating strong positive association. Conclusion: It can be concluded that the coastal non-agricultural land is sandy with various hydraulic conductivity values due to different particle size distribution. These data are useful to the scientific community around the world and will be helpful to speculate potential risk factors to life of ecosystem.

关键词： Particle Size Hydraulic Conductivity Soil Disturbance Coastal Land Soil Profile Ecosystem

Leaching Potential of Diuron and Linuron in Gaza Soils

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American Journal of Plant Sciences 2014年第26期5卷 4040-4049页

作者： yasser El-Nahhal mohamed Abadsa Samir Affifi Department of Environment and Earth Sciences The Islamic University Palestinian National Authority (PNA) Gaza Palestine

This study investigated the leaching potential of diuron and linuron in different soil types in Gaza Strip, Palestine under laboratory and field conditions. Leaching potential was evaluated by tin columns and bioassay technique using Molokhia as test plant. The responses of the test plant were regressed versus concentrations of the herbicide to estimate linear regression equation and the regression coefficient. The obtained results indicate strong positive association between Molokhia and concentrations of diuron or linuron;accordingly it was used in the bioassay and estimation of the concentrations of the tested herbicides in the leaching depth. Leaching potential was very low in North Gaza and Kkan Younis soil, whereas in the Meddle zone soil was very large. Leaching potential under laboratory conditions was larger that under field conditions. The bioestimated concentrations in soil layer under field conditions were sever folds of magnitude lower than those under laboratory conditions. The interesting outcome of this study is that leaching potential is dependent on soil clay fraction, soil organic matter, and soil pH. These results provided answers to the questions raised by farmers in Gaza Strip.

关键词： Leaching Potential Diuron Linuron Clay Fraction Soil Organic Matter Soil pH

Adsorption of Diuron and Linuron in Gaza Soils

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American Journal of Analytical Chemistry 2013年第7期4卷 94-99页

作者： yasser El-Nahhal mohamed Abadsa Samir Affifi Department of Earth and Environmental Sciences The Islamic University of Gaza Gaza Palestine

This study investigated the adsorption potential of diuron and linuron in selected soil samples collected from agricultural area of Gaza Strip, Palestine and correlated the adsorption results to the soil properties. The adsorption experiments are based on the batch equilibrium technique and UV-Spectrophotometer method to determine the equilibrium concentration of both herbicides. Results of adsorption experiment showed that linuron and diuron are adsorbed in various amounts in Gaza soils according to the variation in pH, organic matter and clay content. Adsorption isotherms of both herbicides were linear in the tested concentration. Fitting the adsorption data to Freundlich equation showed good fitting and Freundlich constants were less than one indicating physical adsorption processes. It is concluded that soil organic matter and pH affect the adsorption of both herbicides. These results provided a better understanding of the behavior of diuron and linuron in Gaza soils.

关键词： Adsorption Diuron Linurn Soil Gaza

Effect of Adding a Delayed Blastocyst to a Good Quality One during Embryo Transfer on ICSI Cycle Outcomes

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Open Journal of Obstetrics and Gynecology 2021年第8期11卷 1050-1063页

作者： mohamed Elmahdy Emadeldin Khalifa Passant Radwan yasser Elkassar Faculty of Medicine Obstetrics and Gynecology Department Alexandria University Alexandria Egypt Egyptian Ministry of Health Hospitals Alexandria Egypt

Objectives: Study the effect of adding a delayed blastocyst to a transferred good quality one on ICSI cycle outcomes. Study design: Prospective cohort study. Participants/materials, setting, methods: 90 infertile patients aged from 20 - 35 years due to mild male factor, unexplained infertility or tubal factor. Patients with PCOS, endometriosis, RIF, poor responder and azoospermia were excluded. Setting: Duration 6 months from October 2019 to April 2020 in a private IVF center in Egypt. 30 cases were subjected to elective single embryo transfer and the other 60 with two embryo transfers, one good quality and another poor quality blastocyst. Results: (clinical pregnancy rate) was comparable between the two groups, being 47.7% and 36.7% in SET and DET groups respectively (p = 0.361). Miscarriage and ectopic pregnancy rate were observed in 10% of the cases pregnant after SET (group I) and in only 6.7% of the cases pregnant after DET (group II) denoting no significant statistical difference between the two groups. The highest incidence was missed miscarriages in the two groups and ectopic pregnancy was observed only in one case in group II (DET). Twin pregnancy occurred in 22% of pregnant females in the second group. Late pregnancy complications in the form of preterm labour, premature rupture of membrane and preeclampsia occurred mainly in pregnant females in the second group 18%. Conclusion: Neither adding a delayed blastocyst negatively affected the good one nor affected

关键词： Embryo Transfer ICSI Delayed Blastocyst Pregnancy Rate

Is There Any Role for Calcium Ionophore in ICSI Cycles for Cases of Non Obstructive Azoospermia?

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Open Journal of Obstetrics and Gynecology 2021年第8期11卷 1037-1049页

作者： mohamed Elmahdy yasser Oreif Soad Musleh Emadeldin Khalifa Obstetrics and Gynecology Alexandria University Alexandria Egypt

Objectives: Evaluate the effect of artificial oocyte activation (AOA) using calcium ionophore (A23187) on the rate of fertilization and cleavage of embryos in surgically retrieved sperm of patients with non-obstructive azoospermia undergoing intracytoplasmic sperm injection (ICSI). Study design: This study was conducted on 60 infertile couples undergoing ICSI cycles as a randomized controlled parallel group’s experimental study in a private IVF center in Egypt from January 2018 to July 2019. ICSI cycles were divided into two groups: Group A: includes 30 ICSI patients with surgically retrieved sperms of non-obstructive azoospermia treated with calcium ionophore (A23187). Group C/Control: includes 30 ICSI patients with surgically retrieved sperms of non-obstructive azoospermia non-treated with calcium ionophore (A23187). Results: There was no statistical difference between both groups regarding the fertilization rate (p = 0.853). There was no statistical difference between them regarding implantation rate (p = 0.237). The percentage of Class A embryos in the ca ionophore group was 81.7%, while it was 82.8% in the control group. There was insignificant difference between them (