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Localized Corrosion Behavior of 6% mo Super Austenitic & 316L Stainless Steels in Low pH 3% NaCl Solution

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Journal of materials Science & Technology 2005年第4期21卷 465-469页

作者： m.m.A.Gad H.G.Salem A.m.Nasreldin H.sabry A.A.EI-Sayed metallurgy Department Atomic Energy Authority Cairo EgyptMechanical Engineering Department AUC Cairo EgyptMetallurgy Department Atomic Energy Authority Cairo EgyptEuropean Neighbourhood and Partnership Instrument (ENPI) Cairo EgyptMetallurgy Department Atomic Energy Authority Cairo Egypt

Electrochemical techniques were applied to study the crevice corrosion resistance of two types of stainless steel alloys namely, conventional 316L and 6% mo super austenitic in acidified 3% NaCl solution at room *** results showed that 6% mo alloy possessed a remarkable resistance to crevice corrosion compared with 316L alloy when they are tested in the same solution. The breakdown potential at which passivity broke down for 316L alloy was 0.00 mV （SCE）. The corresponding value for 6% mo alloy could not reach up to the potential value of 700 mV （SCE）. 316L alloy suffered extremely from crevice corrosion at room temperature （about 25℃）, which indicates that the critical crevice corrosion temperature, below which crevice corrosion does not occur, was lower than the test temperature. For 6% mo alloy, the critical crevice corrosion temperature was higher than the testing temperature. Electrochemical parameters indicated that 6% mo alloy exhibited higher crevice corrosion resistance than 316L alloy.

关键词： Crevice corrosion 6% mo super austenitic Conventional 316L Critical crevice temperature

Product Spacing of Stress–Strength under Progressive Hybrid Censored for Exponentiated-Gumbel Distribution

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Computers, materials & Continua 2021年第3期66卷 2973-2995页

作者： R.Alshenawy mohamed A.H.sabry Ehab m.Almetwally Hisham m.Elomngy Department of mathematics and Statistics King Faisal UniversityAl-Ahsa31982Saudi Arabia Department of Applied Statistics and Insurance Mansoura UniversityMansoura35516Egypt Department of mathematical Statistics Cairo UniversityCairo12613Egypt Department of Statistics Delta University for Science and TechnologyMansoura11152Egypt

maximum product spacing for stress–strength model based on progressive Type-II hybrid censored samples with different cases has been *** paper deals with estimation of the stress strength reliability model R=P(Ymbel distribution random variables with different shape parameters but having the same scale *** stress–strength reliability model is estimated under progressive Type-II hybrid censoring *** progressive Type-II hybrid censoring schemes were used,Case I:A sample size of stress is the equal sample size of strength,and same time of hybrid censoring,the product of spacing function under progressive Type-II hybrid censoring *** II:The sample size of stress is a different sample size of strength,in which the life-testing experiment with a progressive censoring scheme is terminated at a random time T 2 e0;*** maximum likelihood estimation and maximum product spacing estimation methods under progressive Type-II hybrid censored samples for the stress strength model have been discussed.A comparison study with classical methods as the maximum likelihood estimation method is ***,to compare the performance of various cases,markov chain monte Carlo simulation is conducted by using iterative procedures as Newton Raphson or conjugate-gradient ***,two real datasets are analyzed for illustrative purposes,first data for the breaking strengths of jute fiber,and the second data for the waiting times before the service of the customers of two banks.

关键词： Exponentiated Gumbel distribution stress-strength model progressive Type-II hybrid censoring maximum product spacing maximum likelihood

Assessing the Performance of Some Ranked Set Sampling Designs Using Hybrid Approach

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Computers, materials & Continua 2021年第9期68卷 3737-3753页

作者： mohamed.A.H.sabry Ehab m.Almetwally Hisham m.Almongy Gamal m.Ibrahim Faculty of Graduate Studies for Statistical Research Cairo UniversityGiza12613Egypt Faculty of Business Administration Delta University of Science and TechnologyMansoura35511Egypt Department of Statistics Delta University for Science and TechnologyMansouraEgypt High Institute for management Sciences Belqas35511Egypt

In this paper,a joint analysis consisting of goodness-of-fit tests and markov chain monte Carlo simulations are used to assess the performance of some ranked set sampling *** markov chain monte Carlo simulations are conducted when Bayesian methods with Jeffery’s priors of the unknown parameters of Weibull distribution are used,while the goodness of fit analysis is conducted when the likelihood estimators are used and the corresponding empirical distributions are *** ranked set sampling designs considered in this research are the usual ranked set sampling,extreme ranked set sampling,median ranked set sampling,and neoteric ranked set sampling *** intensive monte Carlo simulation study is conducted using Lindley’s approximation algorithm to compute the different designs’-based *** study showed that the dependent design“neoteric ranked set sampling design”is superior to other ranked set designs and the total relative efficiency is higher than the other designs’total relative efficiency.

关键词： Goodness of fit ranked set sampling Weibull distribution Bayesian estimation Lindley’s approximation neoteric ranked set sampling design

Visual and refractive outcomes of posterior chamber phakic IOL in stable keratoconus

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International Journal of Ophthalmology(English edition) 2019年第5期12卷 840-843页

作者： Sherif H Emerah moataz m sabry Hisham A Saad Waleed A Ghobashy Ophthalmology Department Research Institute of Ophthalmology magrabi Eye Hospital Ophthalmology Department Tanta University Ophthalmology Department Suez Canal University

We evaluated the visual and refractive outcomes after phakic visian toric implantable collamer lens(ICL) insertion in stable keratoconus(KC). This retrospective study investigated toric ICL implantation in 14 eyes of 8 patients with stable KC. After 6 mo, the mean uncorrected distance visual acuity improved significantly from 0.77 to 0.15 logmAR. The mean best corrected distance visual acuity(BCDVA) improved from 0.18±0.1 to 0.15±0.1 logmAR. Fifty percent of eyes maintained their preoperative BCDVA; 42.8% gained one line. There was no statistical difference in high order or coma aberration. The mean refractive manifest spherical equivalent(mSE), mean refractive manifest spherical error, mean manifest astigmatism decreased significantly postoperatively. At 6 mo postoperatively, our achieved mean spherical equivalent was approximately 74%. No intraoperative or postoperative complications occurred. Toric ICL implantation was effective, predictable and safe to correct refractive error and improve visual acuity in patients with stable KC.

关键词： coma keratoconus lens implantation intraocular

On the refracted patterns produced by liquid vortices

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Acta mechanica Sinica 2007年第1期23卷 11-15页

作者： yasser Aboelkassem Georgios H.Vatistas mcGill University MontrealQCH3A-2K6Canada Concordia University MontrealQCH3G 1M8Canada

A theoretical analysis of the refracted shadows produced by steady and time-decaying liquid vortices under uniform illumination from above is given in this article. An expression for the induced shadow intensity is derived and found to be a function of the vortex＇s free surface profile, i.e., function of the static pressure distribution. The patterns for different focusing depth are given and compared with previous visualization results from the literature. The phenomenon is examined and illustrated as a bench mark case by using both steady and time-decaying algebraic vortex models. However, this study can be extended to check the feasibility of recovering the main flow properties by analyzing the luminous image intensity of the refracted patterns. The present analysis is valid only when the swirl velocity is order of magnitude higher than the meridional flow components and the vorticity is concentrated within the core region and of intense conditions.

关键词： Fluid dynamics - Vortices - Dark shadows Intensity - Time decay

Direct-acting antivirals sofosbuvir and daclatasvir attenuate carbon tetrachloride-induced liver fibrosis in mice

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Liver Research 2023年第1期7卷 71-81页

作者： mayadah m.Abdelsalam Nageh El-mahdy sabry Abou-Saif Department of Pharmacology and Toxicology Faculty of PharmacyTanta UniversityTantaEgypt Department of Tropical medicine and Infectious Diseases Faculty of MedicineTanta UniversityTantaEgypt

Background and aim:Advanced liver fibrosis is a major risk for developing hepatocellular carcinoma(HCC)in chronic hepatitis C virus(HCV)***-acting antivirals(DAAs)which are used for treating HCV infection,produce more than 90%cure rate but do not seem to diminish the rate of occurrence or recurrence of *** study aimed to investigate the effect of DAAs sofosbuvir(SOF)and daclatasvir(DAC)on carbon tetrachloride(CCl4)-induced fibrotic changes in ***:Eighty adult male Swiss albino mice were randomly allocated into 8 groups(10 mice/group):normal control group,SOF group(receiving SOF 80 mg/kg body weight(BW),oral gavage,daily),DAC group(receiving DAC 30 mg/kg BW,oral gavage,daily),SOF t DAC group(receiving a combination of both,daily),CCl4 model group(receiving CCl42 mL/kg BW,intraperitoneal twice weekly)and three CCl4-intoxicated groups receiving either SOF or DAC or their *** CCl4 groups received CCl4 for 12 weeks followed by DAAs for another 12 ***:CCl4-induced a significant elevation of alanine aminotransferase(ALT)and aspartate aminotransferase(AST),and produced histopathological evidence of fibrosis and liver degeneration along with a significant increase(P0.001)of the proliferation markers(proliferating cell nuclear antigen(PCNA)and Ki-67),hepatic stellate cells(HSCs)activation markers(alpha-smooth muscle actin(a-SmA)and glial fibrillary acidic protein(GFAP)),fibrosis marker(matrix metalloproteinase-9(mmP-9))and proinflammatory cytokine(tumor necrosis factor-alpha(TNF-a)).CCl4-intoxicated mice treated with SOF,DAC,or their combination revealed a significant amelioration(P0.001)of CCl4-induced elevation of liver enzymes,fibrotic changes,and liver degeneration along with a significant attenuation(P0.001)of CCl4-induced upregulation of all tested *** effects of SOF,DAC,and their combination on liver enzymes were comparable while the effect of SOF t DAC combination on mitigating CCl4-induced upregulation of the

关键词： Direct-acting antivirals(DAAs) Sofosbuvir(SOF) Daclatasvir(DAC) Carbon tetrachloride(CCl4) Liver fibrosis Hepatocellular carcinoma(HCC)

Rudists(Bivalvia) from a Cretaceous Platform in Northern Egypt: Taxonomy and Paleobiogeography

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Acta Geologica Sinica(English Edition) 2021年第6期95卷 1967-1983页

作者： yasser SALAmA Jamaan S.AJAREm Ahmed A.ALLAm Ahmed m.ALmALKI Geology Department Faculty of ScienceBeni-suef UniversityBeni-suef 65211Egypt Department of Zoology College of ScienceKing Saud UniversityRiyadh 11451Saudi Arabia Department of Zoology Faculty of ScienceBeni-suef UniversityBeni-suef 65211Egypt

New well-preserved rudist materials come from the Barremian–Turonian marine formations in the Yelleg, minsherah, maaza, and Raghawi sections in North Sinai, northern Egypt. There, 17 discovered rudist species belonging to 13 genera and seven taxonomic families are described in detail as follows: Eoradiolites plicatus(Conrad), Eoradiolites liratus(Conrad), Praeradiolites ponsianus(d'Archiac), Archaeoradiolites sp., Bournonia africana Douvillé, Bournonia fourtaui Douville, Biradiolites lombricalis(d'Orbigny), Biradiolites zumoffeni Douville, Radiolites lewyi lewyi Parnes, Radiolites sauvagesi(d'Hombres-Firmas), Durania arnaudi(Choffat), Toucasia carinata(matheron), Toucasia sp., Neocaprina raghawiensis Steuber and Bachmann, Sellaea sp., Ichthyosarcolites sp. and Horoiopleura sp.. The Cenomanian deposits in the northern Eastern desert of Egypt only contain E. liratus. The domination of the Cenomanian rudist species in North Sinai, however, is attributed to changes in the platform, which passes mainly from carbonate in the north to siliciclastics in the south. The presence of Horiopleura sp. in the late Barremian-early Aptian deposits is documented for the first time, which suggests the expansion of taxa of the genus Horiopleura Douville to North Sinai during this interval. The age of the rudist species is documented from the late Barremian-Turonian formations, with their geographic distribution in the mediterranean region considered..

关键词： invertebrate paleontology mollusks rudists Taxonomy Paleobiogeography Barremian–Turonian Egypt

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C3-modules

Algebra Colloquium 2015年第4期22卷 655-670页

作者： Ismail Amin yasser Ibrahim mohamed Yousif Department of mathematics Faculty of Science Cairo University Giza Egypt Department of mathematics The Ohio State University Lima Ohio 45804 USA

One of the continuity conditions identified by Utumi on self-injective rings is the C3-condition, where a module m is called a C3-module if whenever A and B are direct summands of m and A A B = 0, then A B is a summand of m. In addition to injective and direct-injective modules, the class of C3-modules includes the semisimple, continuous, indecomposable and regular modules. Indeed, every commutative ring is a C3-ring. In this paper we provide a general and unified treatment of the above mentioned classes of modules in terms of the C3-condition, and establish new characterizations of several well known classes of rings.

关键词： injective and quasi-injective modules C2-modules and C3-modules

Resistance Analysis of a Semi-SWATH Design Concept in Shallow Water

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Journal of marine Science and Application 2017年第2期16卷 182-189页

作者： Arifah Ali Adi maimun yasser m. Ahmed Rahimuddin marine Technology Center Department of Aeronautics Automotive & Ocean Engineering Universiti Teknologi MalaysiaSkudai 81310 UTM Malaysia Department of Naval Architecture and marine Engineering Faculty of Engineering Alexandria University Alexandria 21526 Egypt Program Studi Teknik Sistem Perkapalan Universitas Hasanuddin Makassar 90245 Indonesia

Resistance analysis is an important analytical method used to evaluate the hydrodynamic performance of High Speed Craft (HSC). Analysis of multihull resistance in shallow water is essential to the performance evaluation of any type of HSC. Ships operating in shallow water experience increases in resistance because of changes in pressure distribution and wave pattern. In this paper, the shallow water performance of an HSC design concept, the semi-Small Waterplane Area Twin Hull (semi-SWATH) form, is studied. The hull is installed with fin stabilizers to reduce dynamic motion effects, and the resistance components of the hull, hull trim condition, and maximum wave amplitude around the hull are determined via calm water resistance tests in shallow water. These criteria are important in analyzing semi-SWATH resistance in shallow water and its relation to flow around hull. The fore fin angle is fixed to zero degrees, while the aft fin angle is varied to 0o, 5o, 10o, and 15o. For each configuration, investigations are conducted with depth Froude numbers (FrH) ranging from 0.65 to 1.2, and the resistance tests are performed in shallow water at the towing tank of UTm. Analysis results indicate that the resistance, wave pattern, and trim of the semi-SWATH hull form are affected by the fin angle. The resistance is amplified whereas the trim and sinkage are reduced as the fin angle increases. Increases in fin angle contribute to seakeeping and stability but affect the hull resistance of HSCs.

关键词： resistance wave height semi-SWATH shallow water fin stabilizers