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基于有限元法的T型梁合理设计

Journal of Marine Science and Application 2021年第2期20卷 302-316页

作者： ahmed Hammad yehia abdel-Nasser Mohamed Shama Department of Naval Architecture and Marine Engineering Faculty of EngineeringAlexandria UniversityAlex andria 21544Egypt

The main configuration of ship construction consists of standard and fabricated stiffening members,such as T-sections,which are commonly used in shipbuilding.During the welding process,the nonuniform heating and rapid cooling lead to welding imperfections such as out-of-plane distortion and residual stresses.Owing to these imperfections,the fabricated structural members may not attain their design load,and removing these imperfections will require extra man-hours.The present work investigated controlling these imperfections at both the design and fabrication stages.A typical fabricated T-girder was selected to investigate the problem of these imperfections using double-sided welding.A numerical simulation based on finite element modeling(FEM) was used to investigate the effects of geometrical properties and welding sequence on the magnitude of the welding imperfections of the T-girder.The FEM results were validated with the experimental measurements of a double-sided fillet weld.Regarding the design stage,the optimum geometry of the fabricated T-girder was determined based on the minimum steel weight and out-of-plane distortion.Furthermore,regarding the fabrication stage,a parametric study with two variables(geometrical properties and welding sequence)was conducted to determine the optimum geometry and welding sequence based on the minimum welding out-of-plane distortion.Increasing the flange thickness and reducing the breadth while keeping the T-girder section modulus constant reduced the T-girder weight and out-of-plane distortion.Noncontinuous welding produced a significant reduction in the out-of-plane distortion,while an insignificant increase in the compressive residual stress occurred.

关键词： Out-of-plane distortion Finite element modeling Welding residual stresses Fabricated T-girder Section modulus

Does local vaginal estrogen after tension-free transobturator vaginal tape reduce overactive bladder symptoms in postmenopausal women? A prospective randomized, controlled study

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Asian Journal of Urology 2024年第1期11卷 86-92页

作者： Samer Mahmoud Morsy Dalia Farouk Sara Hassan ahmed yehia abdelaziz Hussein Aly Hussein Urology Department Kasr Al Ainy HospitalCairo UniversityCairoEgypt Obstetrics and Gynecology Department Kasr Al Ainy HospitalCairo UniversityCairoEgypt

Objective:We aimed to evaluate the efficacy of topical estrogen after transvaginal tension-free vaginal tape-obturator(TVT-O)in the treatment of de novo overactive bladder symptoms that appear after surgery.Methods:This is a prospective randomized controlled study performed in the Urology and Gynecology Departments,Kasr Al Ainy Hospital,Cairo University,Cairo,Egypt.Two hundred and ten postmenopausal females presenting during the period between January 2017 and November 2020 with stress urinary incontinence were included in the study.Patients were divided into two groups,105 patients in Group A(treatment group)and 105 patients in Group B(control group).Patients in Group A underwent transvaginal TVT-O followed by local vaginal estrogen treatment for 6 months,while patients in Group B underwent transvaginal TVT-O only.The study included any postmenopausal female with urodynamic stress urinary incontinence.All patients had to fulfill a 3-day bladder diary,overactive bladder symptoms score,urine analysis,urodynamic study,and post-voiding residual urine measurement by abdominal ultrasound preoperatively and at 3-month and 6-month follow-ups.Results:At 6-month follow-up,daytime frequency was reduced to 8%in Group A(increased to 21%in Group B)with a statistically significant difference between both groups(p=0.009).At 6-month follow-up,nocturia was 8%in Group A(11%in Group B)with no statistically significant difference between both groups(p=0.469).There was a statistically significant difference between both groups as regards to urinary urgency at 6-month follow-up(p=0.024).There was a statistically significant difference in postoperative wound healing events as regards to cure,hyperemia,gapping,and wound infection 1 week after intervention between both groups(p=0.008).No local or systemic side-effects were reported from local estrogen use.Conclusion:Local vaginal estrogen treatment given to postmenopausal patients after midurethral sling procedures can reduce the symptoms of daytime frequency and urinary urgency.Long-ter

关键词： Stressurinary incontinence Estrogen Midurethral sling Overactive bladder symptom

Hydrogeochemical Characteristics and Assessment of Water Resources in Beni Suef Governorate, Egypt

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Open Journal of Geology 2014年第2期4卷 44-57页

作者： ahmed Melegy ahmed El-Kammar Mohamed Mokhtar yehia Ghadir Miro Central Laboratory for Environmental Quality Monitoring National Water Department of Geological Sciences National Research Centre Dokki Egypt Department of Geology Faculty of Science Cairo University Giza Egypt

The main target of this research is to investigate the hydrogeochemical characteristics of surface and groundwater resources in Beni Suef Governorate, Egypt. A combination of major and heavy metals has been used to characterize surface and groundwater in Beni Suef Governorate, Egypt. Twenty water samples were collected from the water resources: River Nile, El-Ibrahimia canal, Bahr Youssef, irrigation and drainage channels and Quaternary aquifer. The collected water samples were analyzed for major and heavy metals. Surface and groundwater in the study area are considered potable for drink and irrigation based on the TDS and major ions concentrations. Regarding the MPL quoted by the WHO [1] and FAO [2], water resources in the study area are polluted by Al, Cd, Fe, Mn, Co and Cu. The highest concentrations of Al, Cd, Fe, Mn, Co and Cu recorded in the study area were 2545, 400, 1415, 2158, 239 and 1080 μg/l, respectively. Both surface and groundwater in Beni Suef suffer from pollution due to the impact of unsupervised anthropogenic activities including: fertilizers and pesticide, waste disposal and industrial waste, seepage from septic tanks, construction of water pipes, wastewater from El-Moheet drainage and evaporation processes during flood irrigation.

关键词： Beni Suef Surface Water Groundwater Hydrogeochemical Characteristics Heavy Metals

The Effect of Early versus Traditional Hospital Discharge on Activities of Daily Living for Women Undergoing Elective Cesarean Section. An Observational Cohort Study

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Open Journal of Obstetrics and Gynecology 2023年第3期13卷 642-653页

作者： ahmed Mohammed Elmaraghy Rasha Elhoseny yehia ahmed Hamdy Naguib Department of Obstetrics and Gynecology Faculty of Medicine Ain Shams University Cairo Egypt Department of Obstetrics and Gynecology The National Medical Institute of Damanhour Ministry of Health Cairo Egypt

Background: Cesarean section is one of the most common surgeries performed worldwide and its consequences and complications represent a major public health concern. The policy of enhanced recovery after surgery has been implemented after cesarean section to optimize perioperative care. Enhanced recovery also aims to reduce the length of hospital stay, which might imply substantial healthcare savings. Rising hospital costs are one of the factors in early discharge. Patients & Methods: This was a prospective cohort study. 158 patients met the inclusion criteria of the study, 81 patients were discharged after 48 hours and 77 patients were discharged after 24 hours. All patients received the same postoperative care and instructions. All the study participants received a phone call 1, 3, and 5 days after discharge to objectively assess the activities of daily living through Katz index of independence in activities of daily living. All patients were offered a postpartum visit 1 week after discharge during which the wound was assessed by the Southampton wound assessment scale. Moreover, other maternal complications such as mastitis, puerperal sepsis, or pyelonephritis were assessed and cases who were readmitted were documented. Initiation of successful breastfeeding and neonatal readmission were reported as well. Results: 158 patients met the inclusion/exclusion criteria of the study. There was no significant difference between the two arms of the study regarding baseline characteristics. Katz index of independence showed that the resumption of activities of daily living after CS was similar in both arms of the study on days 1, 3 and 5 after discharge. Time till the passage of flatus and stool after the cesarean section was significantly shorter among the early discharge arm (9.31 VS 14.68, p value < 0.001 & 13.25 VS 24.82, p value < 0.001 respectively). Maternal readmission was not significantly higher among the early discharge arm and at the 1-week postpartum visit, objective wound assessment by Southampton wound scor

关键词： Cesarean Section Early Discharge Katz Index of Independence in Activities of Daily Living

Thermochemical Aspects of Activated Ammonium Perchlorates with Superior Thermal Stability,Decomposition Enthalpy,Propagation Index,and Decomposition Kinetic Parameters

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Journal of Thermal Science 2021年第6期30卷 2196-2201页

作者： SHERIF Elbasuney M.yehia SHUKRI Ismael SHERIF Farag ahmed Saleh GHARIEB S.El-Sayyad Head of Nanotechnology Research Center Military Technical College(MTC)Cairo 11646Egypt School of Chemical Engineering Military Technical College(MTC)Cairo 11646Egypt Science and Technology Center of Excellence Cairo 11646Egypt Drug Radiation Research Department National Center for Radiation Research and Technology(NCRRT)Egyptian Atomic Energy Authority(EAEA)Cairo 11646Egypt

Ammonium perchlorate(AP)includes oxidizing and reducing elements on the same molecule.AP can act as an efficient oxidizer and mono-propellant as well.In this study,AP experienced crystallographic phase change from orthorhombic centrosymmetric to non-centrosymmetric under controlled isothermal heat treatment.XRD diffractograms confirmed this crystallographic phase change.The thermal behaviour of activated AP had been investigated using DSC.Activated AP demonstrated high chemical stability with an increase in endothermic phase transition enthalpy by 170%.The enthalpy of the subsequent two main exothermic decomposition reactions was increased by 250%.Whereas AP demonstrated total decomposition enthalpy of 733 J/g,activated AP showed 2614 J/g.Activated AP can secure self-sustained response at a high rate.Propagation index(combustion enthalpy/ignition temperature)was employed to assess self-sustained reaction propagation.Activated AP demonstrated high propagation index of 8.7 compared with 2.5 for un-activated AP.Primary decomposition kinetic parameters had investigated using Kissinger and KAS methods.Activated AP showed an increase in activation energy by 89%using the Kissinger method;kinetic parameters using the KAS method were in good agreement with the Kissinger method.It can have concluded that AP with novel kinetic decomposition parameters for enhanced safety storage and high combustion characteristics has evolved.

关键词： solid propellants oxidizers thermal behavior Kinetic parameters activation energy

In vitro evaluation of antimicrobial and antioxidant activity of Dragon’s blood tree(Dracaena cinnabari Balf.f.)of Socotra Island(Yemen)

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Journal of Coastal Life Medicine 2013年第2期1卷 123-129页

作者： Abu-Taleb ahmed yehia Fahad ahmed Mohsen Alzowahi Tukaram Angadrao Kadam Rafik Usman Shaikh Department of Microbiology School of Life SciencesS.R.T.M.UniversityNanded-431606(MS)India Department of Microbiology Taiz UniversityYemen

Objective:To evaluate the performance of preliminary phytochemical,antioxidant and antimicrobial activities of Dracaena cinnabari Balf.f.(Agavaceae)(D.cinnabari)resin,collected from Socotra Island(Yemen).Methods:The powdered stem resin is extracted with different solvents by using Soxhlet apparatus and evaluated for antioxidant and antimicrobial activity against three Gram positive bacteria(Bacillus cereus NCIM 2106,Staphylococcus aureus NCIM 2127,and Micrococcus luteus NCIM 2169),seven Gram negative bacteria(Escherichia coli NCIM 2924,Pseudomonas aeruginosa NCIM 2863,Salmonella typhimurium NCIM 2501,Klebsiella aerogenes NCIM 2281,Proteus morganii NCIM 2860,Escherichia coli dh5α,Escherichia coli CSH)and three fungi(Candida albicans MTCC 227,Aspergillus flavus MTCC 873,Aspergillus niger MTCC 1781).Results:The antimicrobial activity data revealed that,the selected microorganisms possess varied sensitivity response to chloroform extract followed by methanol and benzene extract of D.cinnabari stem resin.The samples also possess a potent DPPH,OH and SO radical scavenging activity.In addition,the preliminary phytochemical analysis demonstrated the presence of alkaloids,flavonoids,terpenoids and other organic compounds which could be reason for antimicrobial activities of D.cinnabari resin.Conclusions:The present study is strengthened for the discovery and development of new antioxidant and antimicrobial drugs from D.cinnabari resin which encourage us to continue with pure fractions.

关键词： Dracaena cinnabari Socotra Yemen Resin Antimicrobial Antioxidant Phytochemical screening

The Art of Talc Flotation for Different Industrial Applications

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Journal of Minerals and Materials Characterization and Engineering 2016年第3期4卷 218-227页

作者： Tawfik Refaat Boulos Suzan Sami Ibrahim ahmed yehia Central Metallurgical Research and Development Institute (CMRDI) Cairo Egypt

Talc has found a steadily increasing number of uses such as cosmetics, steatite and cordierite ceramics, for pitch control in the paper industry and as a reinforcing filler in rubber, etc. In this research, the amenability of some Egyptian carboniferous finely disseminated talc ores to beneficiation by flotation was investigated on laboratory scale. The original talc sample is characterized by low MgO content (25.40%), low SiO2 (45.71%), high CaO content (6.32%) and high L.O.I. (11.35%), indicating its low grade. Attrition scrubbing of the crushed ores was found to be an unconventional process, not only for fine talc production, but also for proper separation of the harder carbonaceous gangue. Talc pre-concentrates, less than 0.074 μm, were prepared by attrition scrubbing in the laboratory having 8.40% L.O.I. with a yield reaching 74.70%. Cleaner talc concentrate with L.O.I. content averaging 6.70% was obtained by flotation in the presence of Aerofroth 71 with a yield reaching 64.71%. This was relatively improved by the use of a selective (quaternary amine) talc collector and in presence of a selective carbonate depressant (soda ash). Flotation of the fine ground talc (less than 22 μm) produced a talc concentrate assaying 6.90% L.O.I. with a yield recovery of 62.91%. However, different talc concentrates obtained by just natural floatability or by the use of small dose of Aerofroth 71, or by the application of quaternary amine in presence of carbonate depressant, satisfy the requirement of paper coating, ceramics production, functional filler, and pharmaceuticals applications. Tailings could also be used in carpets, roofs, and tiles production industries.

关键词： Flotation Depression Attrition Scrubbing Carbonate Separation

Differential Flotation of Some Egyptian Feldspars for Separation of Both Silica and Iron Oxides Contaminants

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Journal of Minerals and Materials Characterization and Engineering 2015年第6期3卷 435-443页

作者： Tawfik Refaat Boulos Suzan Sami Ibrahim ahmed yehia Central Metallurgical Research & Development Institute (CMRDI) Cairo Egypt

An anionic-cationic flotation of two Egyptian feldspar samples, representing Road Ashaab locality of the Eastern Desert of Egypt, was investigated on both laboratory and pilot plant scales. The pegmatites belong to the alkali feldspar granite type, mostly microcline and orthoclase, KAL Si3O8 coarse grained rocks. Quartz, as the main gangue mineral, occurs in two forms as either free grains or as veins intercalating the feldspar crystals or, sometimes, intermingled with them. Iron, on the other hand, is found in three different forms as free magnetite embedded in the feldspar crystals, as microcrystalline crystals, or as magnetite filling cracks in the feldspar. Dissolution of magnetite to hematite is, sometimes, observed. Grinding of the feldspar samples to less than 0.25 mm followed by desliming was optimized in the laboratory, using a ball mill in closed circuit with the screen. Anionic flotation of the iron oxide impurity from the -0.25 + 0.03 mm ground product was successfully conducted using locally produced dodecyl benzene sulphonic acid—rice bran oil/kerosene promoter at pH 3. Cationic flotation of feldspar from this product was then carried out employing a locally produced quaternary ammonium salt in presence of HF acid, as a silica depressant and a feldspar activator at pH 3. Feldspar final concentrates assaying 80.8% - 89.5% feldspar mineral, 0.119% - 0.127% Fe2O3 and 16.84% - 18.65% Al2O3, were obtained at the optimum operating conditions that satisfy the requirements of the ceramic industry. Continuous 200 kg/h pilot plant runs were conducted using the appropriate equipment, based upon the laboratory findings to produce feldspar concentrates assaying 16.38% - 18.13% Al2O3, and 0.13% - 0.15% Fe2O3. Materials’ metallurgical balance and complete chemical analyses were shown.

关键词： Na-Feldspar K-Feldspar Flotation Sand Separation Effect of pH

Utilization of Amaranth Flour in Preparation of High Nutritional Value Bakery Products

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Food and Nutrition Sciences 2020年第5期11卷 336-354页

作者： Seham yehia Gebreil Maha Ibrahim Kamal Ali Esraa ahmed Mohamed Mousa Department of Crops Technology Research Food Technology Research Institute Agricultural Research Center Giza Egypt Department of Special Food and Nutrition Food Technology Research Institute Agricultural Research Center Giza Egypt

Amaranth has become an unconventional crop that interesting of scientists and researchers due to its unique nutritional properties, in addition to bear the water lack and be suitable for all types of soil. The objective of this study was to utilize amaranth flour in preparation of high nutritional value bakery products, crackers and tortilla produced by using amaranth flour instead of corn flour (w/w) by 0%, 25%, 50%, 75% and 100% levels substitution. The prepared products were evaluated for its chemical composition, minerals content, amino acids composition, fatty acid composition, color analysis, biological active compounds analysis and sensory evaluation. Results showed that substitution with amaranth flour increased protein, fat, ash and fiber. As for minerals and amino acid, it indicated that the formula No. 3 (25% corn flour/75% amaranth flour) in crackers and the formula No. 2 (50% corn flour/50% amaranth flour) in tortilla contained higher amount of minerals such as iron, calcium, potassium, zinc, magnesium, manganese, copper and phosphorus, and of the essential amino acids such as Leucine, Lysine and valine. On the other hand the formula No. 3 in crackers had the highest unsaturated fatty acids content and lowest of total saturated fatty acids content. While the formula No. 2 in tortilla had the highest saturated fatty acids content and lowest of unsaturated fatty acids content. The results also showed that the incorporation of amaranth flour in the preparation of the crackers and tortilla led to significantly decreased yellowness and lightness compared with control. Also, results indicated that crackers and tortilla which prepared with amaranth flour exhibited higher antioxidant activity than control formulas. Concerning sensory evaluation of crackers, results showed significant decrease in appearance, color and overall acceptability while, tortilla had significant decrease in general appearance, color and total score at all formulas. Based on the results obtained here, amaranth is a rich source of bioa

关键词： Amaranth High Nutritional Value Crackers Tortilla Nutritional Benefits