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Production and Properties of Superplasticized Concrete

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Journal of Civil Engineering and Architecture 2011年第4期5卷 341-352页

作者： mohamed Attia abd elrahman M. A. Imam Ahmed H. abdel Reheem Ahmed mohamed Tahwia Construction Materials and Chemistry Department Civil Engineering Institute TU Berlin Germany Structural Engineering Department Mansoura University Mansoura 35516 Egypt

The objective of this research is to study the effect of grinding powdered superplasticizer, Portland cement, sand, and silica fume on the properties of fresh and hardened concrete. Lose Angeles Machine was used to grind these constituents. The program was arranged to determine the effect of cycles＇ number, superplasticizer type and dosage, silica fume dosage and condition, and gravel to sand ratio on properties of concrete. Naphthalene sulphonated formaldehyde （NSF） superplasticizers in the forms of liquid and powdered were used. Silica fume may be grinded with the other constituents （grinded）, or added to concrete mixer （normal）. The water/cement （w/c） ratio varied from 0.35 to 0.55 to achieve a constant slump （50-90 mm）. Slumps, bulk density and mechanical properties of concrete were measured. Scanning electron microscope （SEM） was also used to show the differences between traditional and superplasticized concrete. The results showed that grinding the mixture enhances fresh and hardened concrete properties. It is also observed that grinding the mixture for 500 cycles is more effective than other numbers of grinding. In addition, superplasticized concrete exhibits compressive strength higher than traditional one at varied ages. Moreover, using powdered superplasticizer has a remarkable effect on enhancing concrete properties rather than using it in a liquid form. A dosage of 1% by weight of cement gave the highest results of compressive strength. Silica fume has an essential role in improving concrete strength and durability since it acts as very efficient void filler and as a super pozzolana. SEM observations illustrate that grinding the mixture enhances transition zone （TZ） properties and makes it denser. On the other hand, grinded mixture can be packaged in bags and transported for use in crowded cities, and so, enhances quality control, since the only requirement to obtain superplasticized concrete is to add water and gravel. This technique has many benefits s

关键词： Superplasticizer silica fume Los Angeles Machine cycles' number scanning electron microscope transition zone properties of fresh and hardened concrete.

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埃及合资企业的经营管理问题研究

埃及合资企业的经营管理问题研究

作者： HUSSEIN MOSTAFA mohamed abd elZAHER（侯赛因）吉林大学

学位级别：硕士

随着经济全球化,世界各国的经济发展日益密切,世界越来越变成“地球村”。世界各国正在随着全球分工而变得越来越不可分割,各国之间经济上紧密相连、互相协作、互相影响。但必须也要看到,由于各国社会经济等各方面的因素导致发展不平衡... 详细信息

随着经济全球化,世界各国的经济发展日益密切,世界越来越变成“地球村”。世界各国正在随着全球分工而变得越来越不可分割,各国之间经济上紧密相连、互相协作、互相影响。但必须也要看到,由于各国社会经济等各方面的因素导致发展不平衡、不协调的情况仍然存在。很多发展中国家为了发展自己的经济,采用了很多政策措施。其中,合资企业便是在这种背景下应运而生的一种经济组织。合资企业是由于各个合资企业在各国之间的地位越来越重要。同时,合资企业由于其是由本国资本与国外资本共同出资兴办的企业组织,合资各方在文化背景、制度环境、管理模式等方面,都存在着差异。因此,合资企业必须要有与其特殊性相适应的经营管理理论、管理技术和策略。埃及由于近些年来积极支持外国的投资,并在颁布了新的投资法,为外国的投资者制定了很多优惠措施,大力实行引进外资,并出现了很多的合资企业。但是,由于各种原因导致埃及的合资企业发展出现一些问题。主要体现在经营策略的分歧、管理理念的巨大差异、企业文化的不同等造成埃及合资企业的发展受到阻碍,这些问题需要研究,具有较好的实践价值。中国经过近四十年的改革开放,实行改革开放、引进外资、用市场换技术等举措,经济水平发展迅猛,取得了举世瞩目的成就,经济总量目前在世界上居第二位。中国的成功对世界各个发展中国家具有重要的经验借鉴。埃及与中国同是发展中国家,同是文明古国,在世界文化史上具有重要的地位。而在国情方面,中国与埃及面临的许多情况相似,如国有企业较多、人多地少、基础差、底子薄等。因此,借鉴中国的合资企业的发展经验,为埃及的合资企业经营管理提供经验,具有重要的研究意义。同时,中国国内由于实行改革开放,大力发展合资企业的时间较长,很多企业取得了巨大的成功。比如,中国的汽车产业,包括上海大众、一汽大众、东风标致、广州本田等众多的合资车企,为中国的消费者提供了更多优秀的产品,也为中国的经济发展贡献了很多。因此,通过研究中国的合资企业的发展,总结合资企业的发展相对成熟的路径、管理,对埃及的合资企业的发展具有一定的借鉴意义。本文通过研究中国的合资企业的成功经验认为,中国合资企业的成功主要有管理技术的创新、文化的包容、具有弹性的政策支持等是中国合资企业取得成功的重要因素。同时,本文将对中国的合资企业的经营的经验教学进行总结,根据企业管理理论,总结出符合埃及合资企业经营管理的经验,这些对埃及的合资企业的经营管理具有重要的借鉴意义。

关键词：合资企业管理模式管理技术

Effect of Using Baker＇s Yeast and Exogenous Digestive Enzymes as Growth Promoters on Growth, Feed Utilization and Hematological Indices of Nile tilapia, Oreochromis niloticus Fingerlings

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Journal of Agricultural Science and Technology(B) 2012年第1期2卷 15-28页

作者： Ashraf mohamed abdelsamee Goda Hafez abdel-Hamid Hassan Mabrouk mohamed abd EI-Hamid Wafa Tarek mohamed E1-Afifi National Institute of Oceanography and Fisheries （NIOF） Fish Nutrition Laboratory Cairo 24135 Egypt Regional Center for Foods and feeds Agriculture Research Center Ministry of Agriculture Cairo 24135 Egypt

The present study was conducted to evaluate the effect of baker yeast, Saccharomyces cerevisiae （SC） and exogenous digestive enzymes （pepsin, papain and a-amylase, EDE） dietary supplementation on growth performance, feed utilization and hematological indices of Nile tilapia, Oreochromis niloticus fingerlings. A total of 630 Nile tilapia fingerlings with an average body weight of 26.4 ± 0.2 g were divided in the seven experimental net-pen treatments （three replicates each）. The experiment was conducted for 119 days. Seven isonitrogenous （26.50%） digestible protein and isocaloric （13.40 MJ kgl） digestible energy experimental diets were formulated. The control diet had no SC and EDE added. Diets 2-3 each contained SC at levels of 2 and 4 g 100 g diet-t, respectively, while diets 4-5 each contained EDE at levels of （0.64, 1.28, 0.16） and （1.28, 2.56, 0.32） g 100 gdiefI of pepsin, papain and a-amylase, respectively. Diet 6 contained mixture of SC and EDE at levels of 1 g yeast and 0.32, 0.64, 0.08 g of pepsin, papain and a-amylase, respectively 100 gdiet1 and diet D7 contained 2 g yeast and 0.64, 1.28, 0.16 g of pepsin, papain and a-amylase, respectively 100 g dietl. Growth performance and feed utilization efficiency of Nile tilapia were significantly （P 〈 0.05） higher in all treatments receiving SC and/or EDE supplemented-diets than the control diet which suggests that the addition of SC and EDE enhanced the growth performance. Red blood cells counts, hematocrit and hemoglobin were significantly （P 〈 0.05） highest in all treatments receiving mixture of SC and EDE supplemented-diets （D6 ＋ D7）. The same trend was observed for total plasma protein and total plasma globulin levels. The results of present study suggested that Nile tilapia fingerlings fed diets containing the mixture of I g yeast, SC and 0.32, 0.64, 0.08 g of pepsin, papain and a-amylase, respectively 100 gdiet^-1, for 119 days had enhanced growth performance, diet utilization efficiency and hematological ind

关键词： Baker yeast digestive enzymes growth feed utilization hematological indices Nile tilapia.

Application of in-house method for determinationof radium isotopes in environmental samples usingthe Liquid Scintillation counting technique

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Journal of Analytical Sciences, Methods and Instrumentation 2011年第1期1卷 1-8页

作者： Nik Azlin Nik Ariffin Zal Uyun Wan Mahmood Che abd Rahim mohamed 不详

A method for determination of 226Ra and 228Ra in environmental samples using the α-β coincidence liquid scintillation counting (LSC) has been developed. Radium were preconcentrated from environmental samples by coprecipitation with BaSO4, then purified from others radionuclide interferences using the cation column exchange (Bio-Rad AG 50 W-X4 resin with 200-400 mesh size and H+ form) and operating in warm temperature which is between 70-80oC. Then, the Ba(Ra)SO4 precipitate was filtered through the Millipore filter paper, dried and weighed to calculate chemical yield. The activity concentration of radium isotopes in mixture of liquid scintillation cocktails were measured using LSC after being stored for over 21 days to allow the growth of the progeny nuclides. The method has been validated with a certi-fied reference material supplied by the International Atomic Energy Agency and reliable results were obtained. The radiochemical yields for radium were 59% - 90% and recovery was 97% and 80% for 226Ra and 228Ra, respectively. Sixteen seawater and fish flesh samples collected in Kapar coastal water have been analyzed with the developed method. The obtained radium activity concentrations in seawater were in the range of 02.08 ± 0.82 mBq/L to 3.69 ± 1.29 mBq/L for 226Ra and 6.01 ± 3.05 mBq/L to 17.07 ± 6.62 mBq/L for 228Ra. Meanwhile, the activity concentrations of 226Ra and 228Ra in fish flesh were in the range of 11.82 ± 5.23 – 16.53 ± 6.53 Bq/kg dry wt. and 43.52 ± 16.34 – 53.57 ± 19.86 Bq/kg dry wt., respectively.

关键词： 226Ra 228Ra Environmental Samples Chemical Yield Liquid Scintillation Counting

Preoperative Conformal Radiotherapy Concurrently with Paclitaxel/Carboplatin in Gastric Cancer

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Journal of Cancer Therapy 2018年第6期9卷 503-515页

作者： Shimaa Ahmed Mayada Fawzy Khalid Rezk Wessam elshrif mohamed Alaa mohamed M. H. abd ellah Radiation Oncology South Egypt Cancer Institute Assuit University Assiut Egypt Medical Oncology South Egypt Cancer Institute Assuit University Assiut Egypt Surgical Oncology South Egypt Cancer Institute Assuit University Assiut Egypt Clinical Oncology Cairo University Cairo Egypt Clinical Oncology Assuit University Assiut Egypt Diagnostic Radiology South Egypt Cancer Institute Assuit University Assiut Egypt

Background and objectives: Surgery is the primary therapy for localized gastric cancer, but even with the best results only 40% 5-year survival can be achieved with the use of postoperative adjuvant chemoradiotherapy. Preoperative therapy might help increase the R0 resection rate, which is an independent predictor of 5-year OS. Our study hypothesized that the concurrent combination of carboplatin-paclitaxel with radiation therapy would result in a pathological CR rate, which will be in turn associated with OAS and DFS benefits. Patients and methods: prospective phase II study included 32 patients with locally advanced gastric adenocarcinoma including gastroesophageal junction who received a combination of neoadjuvant conformal radiotherapy concurrently with carboplatin-paclitaxel followed by surgery. Results: Pathological CR and R0 resection rates were 18.8% and 75% respectively. With a median follow up of 24 months, 2 years disease-free survival was 28.1% and overall survival was 51.3%. The regimen was tolerated with neither grade 4 toxicities nor deaths. Conclusion: Neoadjuvant radiotherapy concomitant with carboplatin-paclitaxel chemotherapy is a well-tolerated approach for patients with locally advanced gastric adenocarcinoma resulting in significant pathological CR and R0 resection margins as reflected by the good DFS and OS.

关键词： Gastric Adenocarcinoma Neoadjuvant Paclitaxel-Carboplatin Chemoradiotherapy Pathologicalcr-R0

The Need for Cardiac Pacing after Isolated Coronary Artery Bypass Graft Surgery

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Open Journal of Thoracic Surgery 2022年第2期12卷 21-32页

作者： Montaser elsawy abd elaziz Eman Gomaa Saleh mohamed Gaber elsayed Bassem A. Hafez Cardiothoracic Surgery Department Faculty of Medicine Menoufia University Menoufia Egypt Faculty of Medicine Jazan University Jazan Saudi Arabia Neuropsychiatry Department Faculty of Medicine Menoufia University Menoufia Egypt

Background: The aim of this study is to assess the necessity of temporary cardiac pacing and identify the predictors of pacing after coronary artery bypass graft (CABG). Methods: This was a retrospective observational study of 150 patients who had isolated CABG between November 2013 and December 2021. Patients were classified into two groups: group A, (n = 135) who did not need to be paced and group B, (n = 15) who needed temporary epicardial pacing. Only 10% (15/150) of patients in the study needed pacing. The primary outcome variable was assessment of the need for postoperative temporary cardiac pacing (TCP) (patients were paced during chest closure or at any time during hospital admission). The incidence of pacing during the postoperative period was observed. Univariate and multivariate predictors for postoperative pacing were determined and specicific predictors for cardiac pacing were found. Results: In both univariate and multivariate analysis, Old age > 65 years, diabetes mellitus, pacing to come off cardiopulmonary bypass (CPB), CPB time > 100 min, cardioversion to leave OR, antiarrhythmics to leave OR and new onset of atrial fibrillation (AF), were found to be significant predictors for the need to cardiac pacing. Conclusion: After coronary artery bypass surgery, a small percentage of patients require TCP. We emphasize unique predictors for postoperative pacing in this study.

关键词： Temporary Epicardial Pacing Coronary Artery Bypass Arrhythmias

Plasmas Created in the Interaction of Antiprotons with Atomic and Ionized Hydrogen Isotopes. Suggested Fuels for Space Engines

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Journal of High Energy Physics, Gravitation and Cosmology 2022年第1期8卷 14-24页

作者： mohamed Assaad abdel-Raouf abdelfattah T. elgendy Amr abd Al-Rahman Youssef Physics Department Faculty of Science Ain Shams University Cairo Egypt Mathematics Department Faculty of Science Al-Azhar University Cairo Egypt

The main objective of the present work is to investigate the properties of plasmas created by injecting a thermalized beam of antiprotons in two types of media. The first is hydrogen, deuterium, or tritium atoms localized in palladium crystals. The second medium is composed of protons, deuterons, or tritons localized in a magnetic cavity. Particularly, it is demonstrated that huge amounts of energy are released in both cases which could be used as fuels for space shuttle engines. A novel mathematical scheme is employed to calculate the energy yields in real space at different incident energies of the antiprotons.

关键词： Antiprotons Antiprotonic Hydrogens Antiprotonic Plasma Fuel for Space Engines Plasmas in Molecular Crystals Palladium as Host for Neutral Plasma Antiprotons-Ionized Hydrogen Isotopes Plasma

Reproductive Biology of the Striped Seabream Lithognathus mormyrus （Linnaeus, 1758） from AI-Haneah Fishing Site, Mediterranean Sea, Eastern Libya

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Journal of Life Sciences 2016年第4期10卷 171-181页

作者： Eyman Faraj abd Alssalam Sayed mohamed Ali Mohammad E1 Sayed E1 Sayed el Mor Ramadan Attea Saleh Ali Eman Salem AI Fergani Department of Zoology Omar Al-Mukhtar University AI Beida Libya Department of Science Suez Canal University Egypt

Reproductive biology of L. mormyrus was studied using monthly samples totaling 224 fish obtained from AI-Haneah fishing site, eastern Libya Mediterranean Sea. Lengths of the examined fish ranged between 11.5 cm and 23.4 cm. Corresponding weights were 24.5 g and 160.8 g. The minimum values of the condition factors, KF and Kc, were 1.38 and 1.21 at the average fish length of 12.4 cm. These values increased with increases in length until they reached maximum values of 1.59 and 1.41 at the length of 22.1 cm. The high values of KF and Kc, Gonado-Somatic Index and oocyte diameter maintained during May, June, July, and August and the monthly changes in gonadal condition, indicated that summer was the breeding season of L. mormyrus. The oocyte diameter ranged between 379± 25.3 μ and 1,511 ± 143.3μ （n = 76） with an average of 895 ± 111.3 μ. The sex ratio was in favor of females during all months of the study. The overall sex ratio was 1 ： 1.52. Length at first maturity, Ls0, for L. mormyrus was found to be 14.15 cm for males and 14.45 for females. Overall average of absolute fecundity was 4,342±557 egg per fish （n = 45）. The overall average of relative fecundity was 234± 181 egg per cm. Absolute fecundity increased with increasing fish length.

关键词： Reproductive biology length at first maturity oocyte diameter fecundity striped Seabream Lithognathus mormyrus.

Ultrasound Role in Diagnosis of Carpal Tunnel Syndrome and Postoperative Evaluation in Endoscopic Carpal Tunnel Release

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Open Journal of Modern Neurosurgery 2019年第3期9卷 248-257页

作者： Hossam elsobky mohamed Kassem Tamer Youssif Ahmed abd-elkhalek Amr Farid Khalil Neurosurgery Department Mansoura University Mansoura Egypt General Surgery Department Mansoura University Mansoura Egypt Diagnostic and Interventional Radiology Department Mansoura University Mansoura Egypt

Carpal tunnel syndrome (CTS) represents about 90% of all entrapment neuropathies and is caused by entrapment of the median nerve while passing in the carpal tunnel. US has revealed equal effectiveness as magnetic resonance imaging (MRI) in diagnosis of CTS;however further attention should be given in case of equivocal results from nerve conduction studies (NCS) and/or before endoscopic surgical intervention. This study was conducted to evaluate the role of US in diagnosis and treatment of CTS which was done by endoscopic release. This is a prospective study including patients having CTS who were treated by endoscopic release between December 2017 and December 2018. All cases were evaluated by electrophysiological studies and US at the preoperative period. US was used to measure the cross sectional area (CSA) of the median nerve. Patients underwent endoscopic carpal tunnel release and were called for follow up after 1, 3, and 6 months for clinical and US assessment of the median nerve. Forty cases were included with mean age of 27.85 years. Numbness was the predominant symptom (92.5%) followed by wrist pain (85%). The mean diameter of median nerve showed a significant decrease at different time points (P electrophysiological study. The sensitivity of US in detecting the improvement of CTS as compared to clinical examination increased from 28% at 1 month postoperative, 53.4% at 3 months to 92.1% at 6 months. Ultrasonography is a sensitive non-invasive diagnostic tool in diagnosis of CTS preoperative and diagnosis of improvement of the patients postoperatively especially at 6 months.

关键词： Carpel Tunnel Syndrome Ultrasonography Endoscopic Release