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Novel synthesis of stabilized Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5) solid electrolytes with enhanced conductivity for intermediate temperature solid oxide fuel cells(SOFCs)

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Journal of Rare Earths 2024年第10期42卷 1903-1911页

作者： Ahmed h.Ibrahim yehia m.abbas.h.a.ayoub marwa h.Ali mustafa Aldoori materials Science Laboratory Physics DepartmentFaculty of ScienceSuez Canal University41522IsmailiaEgypt ministry of higher Education and Scientific Research Aliraqia University10011BaghdadIraq

herein,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi_(2)O_(3) solid electrolyte system via solid-state processing under atmospheric *** with Dy^(3+) and Gd^(3+) has been observed to significantly enhance the densification process during sintering for stabilization purposes,thereby improving the electrical properties of δ-Bi_(2)O_(3)-type *** synthesized ceramics were characterized using X-ray diffraction(XRD),field emission scanning electron microscopy-energy dispersive X-ray spectroscopy(FESEm-EDX),thermal gravimetry/differential thermal analysis(TG/DTA),and the four-point probe technique(4PPT).XRD analysis reveals that the samples Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5)(y=0.05/x=0.05,0.10,0,15,and 0.20,and x=0.05/y=0.10,0.15,and 0.20) exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic *** XRD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic(FCC) structure with a space group of *** micrographs reveal that the composition Bi_(0.90)Gd_(0.05)Dy_(0.05)O_(1.5) has no significant ***,an evident increase in the pore formation is observed as the amount of Gd_(2)O_(3) increases until it reaches 20%.This finding suggests that dense pellets are formed during the sintering process at 900-1000℃.The DTA analyses were performed to verify the phase stability,which agrees with the XRD *** electrochemical performance of the synthesized Dy-Gd co-doped Bi_(2)O_(3)solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy(EIS) technique,Based on EIS and conductivity measurements,Bi_(0.75)Gd_(0.20)Dy_(0.05)O_(1.5) exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627℃compared to the other samples;this composition can be used as a solid electrolyte for intermediatetemperature solid oxide fuel cells(SOFCs).

关键词： Solid oxide fuel cells(SOFCs) Rare earths Solid-state processing Rietveld Fast Fourier transform(FFT) Electrochemical impedance spectroscopy(EIS)

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Does dutasteride reduce the bleeding in transurethral resection of the prostate in patients on antiplatelet drugs?

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Current Urology 2024年第3期18卷 194-198页

作者： Ahmed m.Rammah Alaa meshref Ebram Soliman Islam Nasser Abd Elaziz Enmar habib Ahmed yehia Abdelaziz Ahmed h.Abozamel Department of Urology Kasr Alainy HospitalFaculty of MedicineCairo UniversityCairoEgypt El Sahel Teaching hospital CairoEgypt

Background The aim of this study was to assess the effect of a 4-week dutasteride treatment on reducing the intraoperative and postoperative bleeding,as well as the amount and duration of irrigation required to clear the urine after transurethral resection of the prostate(TURP)≥50 g in men receiving the antiplatelet drug(APD).materials and methods This double-blind randomized clinical trial included patients with a prostate size≥50 g who were indicated for TURP and were already receiving *** study was conducted in the Urology Department of Cairo University over a 12-month *** preoperative laboratory investigations were performed in all ***,baseline prostate size,serum prostate-specific antigen level,and International Prostate Symptom Score were *** patients were randomly divided into 2 equal groups(groups A and B).Group A,the dutasteride group,received dutasteride(0.5 mg)once daily for 4 *** B,the placebo group,received a placebo capsule once daily for 4 *** groups underwent bipolar *** patients were excluded from the study;9 patients from group A and 6 patients from group B,either due to drug intolerability or loss *** The mean blood loss was insignificant between the 2 groups immediately after and 24 hours after surgery(Δhemoglobin:1.41±0.63 g/dL vs.1.48±0.54 g/dL,2.12±0.70 g/dL vs.2.31±0.78 g/dL,respectively,p=0.631,p=0.333;Δhematocrit:2.97%±1.51%vs.3.16%±1.36%,4.96%±1.87%vs.5.73%±4.39%,respectively,p=0.610,p=0.380).however,there were significant differences in duration of indwelling urethral catheter(5.10±0.55 days vs.5.80±1.79 days,p=0.048),duration of bladder irrigation(13.60±2.85 hours vs.16.33±6.62 hours,p=0.044),and the amount of saline used for bladder irrigation(11.03±2.30 L vs.13.87±6.13 L,p=0.046)between group A and group *** Treatment with dutasteride for 4 weeks before TURP in men receiving APD did not significantly reduce intraoperative or postoperativ

关键词： Dutasteride Transurethral resection of the prostate Postprostatectomy bleeding Antiplatelet drugs

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PERIODIC mOTIONS OF SPINNING RIGID SPACECRAFT UNDER INFLUENCE OF GRAVITATIONAL AND mAGNETIC FIELDS

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Applied mathematics and mechanics(English Edition) 2006年第8期27卷 1061-1069页

作者： yehia A.Abdel-aziz m.h.yehia F.A.Abd El-Salam m.Radwan National Research Institute of Astronomy and Geophysics Helwan. Cairo Egypt mathematics Department Faculty of Science Mansoura University MansouraEgypt Astronomy Department Faculty of ScienceCairo UniversityCairo12613Egypt

The motion of a magnetized axisymmetric spacecraft about its center of mass in a circular orbit is considered, taking the gravitational and magnetic effects of the central body into account. Equations of motion of the reduced system are transformed to equations of plane motion of a charged particle under the action of electric and magnetic fields. Stationary motions of the system are determined and periodic motions near to them are constructed using the Lyapounoff theorem of the holomorphic integral.

关键词： periodic motions routhian rigid spacecraft

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Simulation-based environmental-impact assessment of glycerol-to-hydrogen conversion technologies

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Clean Energy 2021年第3期5卷 387-402页

作者： yehia F.Khalil Department of Chemical&Environmental Engineering Yale UniversityNew HavenCT 06520USA

This simulation-based comparative assessment aims to quantify the environmental and human-health impacts of greener hydrogen(h2)production via three glycerol-based technologies,including:supercritical water reforming(SCWR),aqueous-phase reforming(APR)and autothermal reforming(ATR).The GaBi(2018 edition)life-cycle assessment(LCA)platform is used to develop cradle-to-gate product system models for these technologies and the TRACI 2.1 methodology is used to quantify their midpoint impact *** hYSYS(v11)process-simulation software is used to generate the life-cycle inventory(LCI)primary data required to produce 1 kg of h2 via each of the indicated glycerol-reforming *** ISO 14040:2006 reporting requirements for the LCA results interpretation step,three base case(BC)scenarios and four sensitivity scenarios(SS)are developed and quantified to compare the effects of different process electricity sources(US grid mix versus wind power)and thermal energy sources(natural gas versus biogas)on the LCA *** high operating pressure(viz.240 bar)of SCWR enabled assessment of the impact of in situ electricity generation to offset some of electricity required for this *** major insights from this research are as follows:(i)per 1 kg of produced h2,APR reduces CO_(2) emissions by≈95%compared to ATR and by≈92%compared to SCWR,(ii)for BC scenarios,the primary energy consumption(in mJ/kg of produced h2)is in the following order from highest to lowest:ATR>SCWR>APR and(iii)h2 production via glycerol APR is more environmentally sustainable than SCWR and ATR,and thus offers a promising path for greener h2 *** environmental sustainability studies should focus on expanding the scope of this study to include h2 production via water electrolysis using renewable electricity sources and via solar and nuclear-driven thermochemical water splitting.

关键词： glycerol hydrogen impact categories reforming supercritical water valorization

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Evaluation of Biomarkers in Egyptian Patients with Different Grades of Nonalcoholic Fatty Liver Disease

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Journal of Clinical and Translational hepatology 2017年第2期5卷 109-118页

作者： Ibrahim h.Borai yehia Shaker maha moustafa Kamal Wafaa m.Ezzat Esmat Ashour mie Afify Weaam Gouda maha m.Elbrashy Biochemistry Department Faculty of Science Ain Shams University Cairo Egypt Biochemistry Department National Research Centre Giza Egypt Department of Internal medicine National Research Center Giza Egypt

Background and Aims:Nonalcoholic fatty liver disease (NAFLD) is a silent disease;its spectrum includes simple steatosis,nonalcoholic steatohepatitis and ***-and anti-inflammatory cytokines play roles in the pathogenesis of NAFLD and insulin resistance (IR).moreover,plasma cell antigen-1 (PC-1) is related to IR and associated with NAFLD ***,we aimed to detect biomarkers,ultrasonographic and anthropometric findings capable of differentiating NAFLD grades,since most previous investigators were concerned more with NAFLD patients without classifying them into ***:A total of 87 NAFLD patients (31 with grade 1 (mild NAFLD),26 with grade 2 (moderate NAFLD) and 30 with grade 3 (severe NAFLD) were included in the study,in addition to 47 controls (grade 0).All subjects underwent ultrasonographic examination for NAFLD *** interleukin-10 (IL-10),plasma interleukin-18 (IL-18) and plasma PC-1 levels were determined using enzyme-linked immunosorbent ***:homoeostasis model assessment (hOmA)-IR was higher in different NAFLD grades than in *** and anthropometric findings and lipid profile indices (except for high-density lipoprotein cholesterol,which was decreased) were increased with NAFLD *** 3 patients showed significant increase in levels of IL-18 and significant decrease in IL-10 and PC-1 levels when compared to grade 1 ***:Anthropometric and ultrasonographic findings were valuable in differentiating NAFLD *** is very important in NAFLD ***-18,hOmA-index and PC-1 levels could be used to differentiate between NAFLD grades,together with other measurements.

关键词： NAFLD Interleukin-18(IL-18) Interleukin-10(IL-10) Plasma cell antigen-1(PC-1)

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high Performance Oil Resistant Rubber

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Open Journal of Organic Polymer materials 2012年第4期2卷 89-94页

作者： A. I. Khalaf A. A. yehia m. N. Ismail h. El-Sabbagh Department of Polymers and Pigments National Research Center Cairo Egypt

Blending of polymers has gained much interest due to the fact that, it can be used to produce new polymeric materials with specific properties suitable for some special applications. The blends from acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR) and polyvinyl chloride (PVC) has been designed for products working in contact with oils. The characteristics of the designed blends either binary blends (NBR/PVC or PVC/CR) or ternary blends (NBR/ PVC/CR) were investigated by rheological properties, mechanical analysis and swelling in oil and toluene. It was found that the incorporation of PVC in the blend compositions leads to the decrease in degree of swelling, the penetration rate and the average diffusion coefficient. On the other hand the ultimate tensile strength (UTS), the hardness and strain energy were increased. This was attributed to the plastic nature of PVC, beside its additional behavior as filler. The crosslinking density in the blend vulcanizates under investigations was determined by Flory-Rehner and mooney-Rivlin [Stress/Strain] equations. The higher values of crosslinking density determined by mooney-Rivlin can be attributed to the additional physical crosslinks (e.g. entanglements etc), beside the chemical crosslinks determined by swelling in toluene. This study showed that NBR/PVC blends are characterized with high performance oil resistant, which can be recommended to automotive industry.

关键词： Blends NBR PVC CR Oil Resistant Thermal Ageing Rheology Strain Energy

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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

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用粘度测定法研究共混橡胶的均相性

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橡胶参考资料 1993年第8期23卷 59-63页

作者： A.A.yehia F.m.helaly S.h.Elsabbagh 田野

1 前言并用橡胶是通过次生作用力而非共价键相互作用的结构上不同的椽胶的物理混合物,由于并用橡胶已成为制备其组份橡胶所不具有的新性能材料的有效途径,最近橡胶并用的重要性已大大提高了。

关键词：粘度测定橡胶共混均相性

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