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Peristaltic Flow of Dusty Nanofluids in Curved Channels

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Computers, Materials & Continua 2021年第1期66卷 1011-1026页

作者： Z.Z.Rashed sameh E.ahmed mathematics department jouf universityqurayyatsaudi arabia department of mathematics king khalid universityabhasaudi arabia

in this paper,numerical investigations for peristaltic motion of dusty nanofluids in a curved channel are *** systems of partial differential equations are presented for the nanofluid and dusty phases and then the approximations of the long wave length and low Reynolds number are *** physical domain is transformed to a rectangular computational model using suitable grid *** resulting systems are solved numerically using shooting method and mathematical forms for the pressure distributions are *** controlling parameters in this study are the thermal buoyancy parameter G_(r),the concentration buoyancy parameter Gc,the amplitude ratio,the Eckert number Ec,the thermophoresis parameter N_(t) and the Brownian motion parameter Nb and the dusty parameters D_(s);α_(s).The obtained results revealed that an increase in the Eckert number enhances the temperature of the fluid and dusty particles while the nanoparticle volume fraction is ***,both of the temperature and nanoparticles volume fraction are supported by the growing of the Brownian motion parameter.

关键词： Peristaltic motion dusty particles nanofluid curved channels

Literature review of the outcome of and methods used to improve transperineal repair of rectocele

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World Journal of Gastrointestinal Surgery 2021年第9期13卷 1063-1078页

作者： Mohammad Fathy ahmed Hossam Elfallal sameh Hany Emile General Surgery Mansoura University Faculty of MedicineMansoura 35516Egypt

BACKGROUND Rectocele is commonly seen in parous women and sometimes associated with symptoms of obstructed defecation syndrome(ODS).AiM To assess the current literature in regard to the outcome of the classical transperineal repair(TPR)of rectocele and its technical *** An organized literature search for studies that assessed the outcome of TPR of rectocele was ***/Medline and Google Scholar were queried in the period of January 1991 through December *** main outcome measures were improvement in ODS symptoms,improvement in sexual functions and continence,changes in manometric parameters,and quality of *** After screening of 306 studies,24 articles were found eligible for inclusion to the *** studies(301 patients)assessed the classical TPR of *** median rate of postoperative improvement in ODS symptoms was 72.7%(range,45.8%-83.3%)and reduction in rectocele size ranged from 41.4%-95.0%.Modifications of the classical repair entailed omission of levatorplasty,addition of implant,concomitant lateral internal sphincterotomy,changing the direction of plication of rectovaginal septum,and site-specific *** The transperineal repair of rectocele is associated with satisfactory,yet variable,improvement in ODS symptoms with parallel increase in quality-of-life *** modifications of the classical TPR were *** modifications include omission of levatorplasty,insertion of implants,performing lateral sphincterotomy,changing the direction of classical plication,and site-specific *** indications for these modifications are not yet fully clear and need further prospective studies to help tailor the technique to rectocele patients.

关键词： Transperineal repair Rectocele Review Modifications Outcome

Nanofluid Flows Within Porous Enclosures Using Non-Linear Boussinesq Approximation

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Computers, Materials & Continua 2021年第3期66卷 3195-3213页

作者： sameh E.ahmed Dalal Alrowaili Ehab Mahmoud Mohamed Abdelraheem M.Aly Department of Mathematics College of ScienceKing Khalid UniversityAbha62529Saudi Arabia Department of Mathematics South Valley UniversityQena83523Egypt Mathematics Department College of ScienceJouf UniversitySakakaSaudi Arabia Electrical Engineering Department College of EngineeringPrince Sattam Bin Abdulaziz UniversityWadi Addwasir11991Saudi Arabia Electrical Engineering Department Aswan UniversityAswan81542Egypt

in this paper,the Galerkin finite element method(FEM)together with the characteristic-based split(CBS)scheme are applied to study the case of the non-linear Boussinesq approximation within sinusoidal heating inclined enclosures filled with a non-Darcy porous media and *** enclosure has an inclination angle and its side-walls have varying sinusoidal temperature *** working fluid is a nanofluid that is consisting of water as a based nanofluid and Al2O3 as *** porous medium is modeled using the Brinkman Forchheimer extended Darcy *** obtained results are analyzed over wide ranges of the non-linear Boussinesq parameter 0≤ζ≤1,the phase deviation 00≤Φ≤1800,the inclination angle 00≤γ≤900,the nanoparticles volume fraction 0%≤φ≤4%,the amplitude ratio 0≤a≤1 and the Rayleigh number 104≤Ra≤*** results revealed that the average Nusselt number is enhanced by 0.73%,26.46%and 35.42%at Ra=104,105 and 106,respectively,when the non-linearBoussinesq parameter is varied from 0 to *** addition,rate of heat transfer in the case of a non-uniformly heating is higher than that of a uniformly ***-linear Boussinesq parameter rises the flow speed and heat transfer in an *** deviation makes clear changes on the isotherms and heat transfer rate on the right wall of an *** inclination angle varies the flow speed and it has a slight effect on heat transfer in an enclosure.

关键词： CBS scheme non-linear Boussinesq approximation nonuniformly heating non-darcy flow nanofluid

The effect of optimism bias and governmental action on siltation management within Japanese reservoirs surveyed via artificial neural network

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Big Earth Data 2020年第1期4卷 68-89页

作者： Tobias Landwehr sameh ahmed Kantoush Claudia Pahl-Wostl Tetsuya Sumi Mitsuteru irie institute for Environmental Systems Research Osnabrück UniversityOsnabrückGermany Water Resources Research Center Disaster Prevention Research InstituteKyoto UniversityKyotoJapan Department of Civil and Environmental Engineering Faculty of EngineeringMiyazaki UniversityMiyazakiJapan

Reservoirs are installed as long-term assets to guarantee water and energy security for decades,if not ***,the effect of siltation undermines reservoirs’sustainability because it significantly reduces the reservoirs’original *** present paper attempts to evaluate the global reservoir siltation problem with the optimism bias theorem introduced by Kahneman and Tversky and applied to infrastructural mega-projects by Flyvbjerg and Ansar using artificial neural networks(ANNs)algorithms for large Japanese *** possesses suitable long-term data and a legal directive concerning the sediment capacity siltation duration,which serves as a valid guide to check whether,over the past 100 years,engineers,planners and managers were capable of judging the sediment input *** ANN models were established to emulate Japanese reservoir siltation *** networks demonstrate that reservoirs in Japan suffer from optimism *** contrast to the law,the dead storage volume of an average dam is supposed to reach capacity after 52 *** finding joins the overall observation that mega-projects generally and globally suffer from optimism *** emulations were subsequently screened for a presumed influence of governance actions,namely,indicating plus monitoring and the change in the market competition *** reservoir siltation appears to continue regardless of the level of competition in public procurement,monitoring directives appear to have a considerable impact on improved siltation management,which demonstrates that dedicated governance action can significantly strengthen the sustainable behavior of key infrastructure elements such as reservoirs.

关键词： Neural networks optimism bias governance Japan sustainability reservoirs sedimentation infrastructure

Cystic pancreatic lesions,the endless dilemma

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World Journal of Gastroenterology 2021年第21期27卷 2664-2680页

作者： Hussein Hassan Okasha Abeer Awad ahmed El-meligui Reem Ezzat Ashraf Aboubakr sameh AbouElenin Ramy El-Husseiny ahmed Alzamzamy Department of internal Medicine and Gastroenterology Hepatology UnitKasr Al-Aini HospitalsCairo UniversityCairo 11562Egypt Department of internal Medicine and Gastroenterology Hepatology UnitAssuit UniversityAssuit 71515Egypt Department of Gastroenterology and Hepatology Maadi Armed Forces Medical ComplexMilitary Medical AcademyCairo 11441Egypt Department of Gastroenterology and Hepatology Military Medical AcademyCairo 11441Egypt Department of Hepatology and Tropical Medicine National Hepatology and Tropical Medicine Research Institute(NHTMRI)Cairo 11441Egypt

Cystic pancreatic lesions involve a wide variety of pathological entities that include neoplastic and non-neoplastic *** proper diagnosis,differentiation,and staging of these cystic lesions are considered a crucial issue in planning further *** are great challenges for their diagnostic *** our time,new emerging methods for this diagnosis have been *** ultrasonography-guided fine-needle aspiration cytology with chemical and molecular analysis of cyst fluid and EUS-guided fine needlebased confocal laser endomicroscopy,through the needle microforceps biopsy,and single-operator cho-langioscopy/pancreatoscopy are promising methods that have been used in the diagnosis of cystic pancreatic *** we discuss the diagnosis of cystic pancreatic lesions and the benefits of various diagnostic models.

关键词： Pancreatic cystic lesion Endoscopic diagnosis Endoscopic ultrasonography Cyst fluid markers Endoscopic ultrasonography-guided fine needle-based confocal laser endomicroscopy Through the needle microforceps biopsy Single operator cholangioscopy/pancreatoscopy

Two-stage procedure in the management of selected cases of keratoconus: clear lens extraction with aspherical iOL implantation followed by WFG-PRK

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international Journal of Ophthalmology(English edition) 2018年第11期11卷 1761-1767页

作者： Waleed Abou Samra Tharwat Mokbel Mohammed Elwan sameh Saleh ahmed Elwehidy Mohammed iqbal Adel Ellayeh Department of Ophthalmology Faculty of Medicine Mansoura University Department of Ophthalmology Faculty of Medicine Sohag University

AiM： To assess the objective and subjective results of a two-stage procedure for management of keratoconus： clear lensectomy with aspherical intraocular lens（iOL） implantation followed by wave front-guided photorefractive keratotomy（WFG-PRK）.METHODS： This prospective interventional non-randomized study included patients aged 35 years old or more with grade i and ii stable keratoconus, a clear visual axis, minimal corneal thickness（MCT） 420 μm or more and average keratometric reading（K） less than 54 diopter（D）. Refraction of all selected eyes should be-8.00 D sphere or more with less than-6.00 D cylinder and could be corrected two lines or more with spectacles or contact lenses. All studied eyes underwent a two-stage approach treatment： first refractive lens exchange and aspherical iOL implantation followed, after at least 3 mo, by WFGPRK. Pre and postoperative complete ophthalmological examination were performed. Topographical, visual and aberrometric results were recorded and evaluated during 6 mo follow up period. Moreover, patient satisfaction and other subjective outcomes were also ***： The 13 eyes of 11 patients diagnosed with stable keratoconus and aged from 39 to 49 y（42.4±6.2 y） were enrolled in the study. At baseline, 8 eyes had grade i and 5 eyes had grade ii keratoconus. The manifest sphere was-10.3±4.2 D（ranged from-8.0 to-14.0 D） and the manifest cylinder was-4.2±1.2 D（ranged from-1.75 to-5.50 D）. After the two-stage procedure, sphere and cylinder reduced significantly to-0.43±0.22 D and-1.3±0.72 D respectively（P〈0.001）. There was also a highly significant improvement in the mean uncorrected distance visual acuity（UDVA） from logMAR 1.41±0.49 preoperatively to 0.51±0.16 postoperatively（P〈0.001） and the mean corrected distance visual acuity（CDVA） from 0.76±0.24 preoperatively to 0.49±0.13 after the operation（P〈0.001）. All aberrometric and mesopic vision parameters and most of the topographical indices demonstrated highly significant improveme

关键词： keratoconus clear lensectomy wave front guided photorefractive keratotomy

Accelerated versus standard corneal cross linking in the treatment of ectasia post refractive surgery and penetrating keratoplasty: a medium term randomized trial

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international Journal of Ophthalmology(English edition) 2019年第11期12卷 1714-1719页

作者： Hany A.Khairy Moataz F.Elsawy Khaled Said-ahmed Marwa A.Zaki sameh S Mandour Department of Ophthalmology Menoufia University Hospitals

AiM: To compare the clinical outcomes of the standard corneal cross linking(CXL) and the accelerated CXL in patients with progressive corneal ectasia post refractive surgery and penetrating ***: Totally 120 eyes of 83 patients scheduled to receive either standard CXL(3 m W/cm^2 for a period of 30 min) or accelerated CXL(18 m W/cm2 for a period of 5 min). The main outcomes for comparison were the change in: maximum-K reading(K-max), manifest refractive spherical equivalent(SE), central corneal thickness(CCT), and the best corrected distance visual acuity(CDVA).RESULTS: One hundred and eleven eyes completed the study. The main outcome measurement was the K-max reading. Both group showed significant improvement in the value postoperatively at 6 and 12 mo. The mean change in the standard group was 1.21±0.11 D and in the accelerated group was 0.90±0.05 D at the end of 12 mo postoperatively, with no statistically significant difference between the 2 groups. Similarly, CDVA improved significantly from their preoperative value in the standard group by 2.98±0.11 letters, and in the accelerated group by 2.20±0.06 letters, with no statistically significant difference between the two groups. Both of the SE, and CCT showed no statistically significant difference at the end of follow up period in each ***: Both standard CXL and accelerated CXL are safe and effective treatment in halting ectasia after corneal refractive surgery. The accelerated CXL results are comparable to the standard CXL with short time exposure of the cornea to ultraviolet irradiation, leading to reduced operation time, reduced operative ocular discomfort, and corneal haze.

关键词： corneal cross linking accelerated refractivesurgery penetrating keratoplasty corneal ectasia

Natural Convection Flow and Heat Transfer Enhancement of a Nanofluid past a Truncated Cone with Magnetic Field Effect

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World Journal of Mechanics 2012年第5期2卷 272-279页

作者： sameh E. ahmed A. Mahdy Mathematics Department Faculty of Science South Valley University Qena Egypt

A nonsimilarity analysis is performed to investigate the laminar, free convection boundary layer flow over a permeable isothermal truncated cone in the presence of a transverse magnetic field effect. A suitable set of dimensionless variables is used and non-similar equations governing the problem are obtained. Fourth order Runge-Kutta with shooting technique is employed for the numerical solution of the obtained equations. Different water-based nanofluids containing Cu, Ag, CuO, Al2O3, and TiO2 are taken into consideration. The effects of pertinent parameters such as the solid volume fraction of nanoparticles, and magnetic field parameter have been investigated. Furthermore, different models of nanofluid based on different formulas for thermal conductivity and dynamic viscosity on the flow and heat transfer characteristics are discussed. Various comparisons with previously published work for the case of a vertical plate are performed and the results are found to be in excellent agreement.

关键词： Nanofluid Truncated Cone Magnetic Field Natural Convection Non-Similarity Solution

Evaluation of Gallium Arsenide Thermal Expansion Coefficient by Extended X-Ray Absorption Fine Structure

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World Journal of Condensed Matter Physics 2019年第2期9卷 37-46页

作者： Gora Dieye sameh i. ahmed Abdou C. Wade Djibril Diop Département de Physique Faculté des Sciences et Techniques Université Cheikh Anta Diop Dakar Senegal Department of Physics Faculty of Science Ain Shams University Cairo Egypt

Negative thermal expansion of gallium arsenide has been investigated through temperature dependent Extended X-ray Absorption Fine Structure (EXAFS) measurements. The bond thermal expansion coefficient αbond has been evaluated and compared to negative expansion coefficient αtens due to tension effects. The overall thermal expansion coefficient is the sum?of?αbond?and αtens. Below 60 K, αtens is greater than αbond? yielding to a negative expansion in this temperature region. Tension effects are progressively overcome by the stretching effects in the region 60 - 300 K. The asymmetry of nearest neighbors distribution is not negligible since the gaussian approximation underestimates the bond expansion by about 0.00426 Å. This error decreases when the temperature is lowered. The accuracy in the thermal expansion evaluation and the connection between third cumulant and thermal expansion are discussed.

关键词： Negative Thermal Expansion Tension Effects EXAFS Asymmetry Gallium Arsenide