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LAMINAR DISSIPATIVE FLOW IN A POROUS CHANNELBOUNDED BY ISOTHERMAL PARALLEL PLATES

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Applied Mathematics and Mechanics(English Edition) 2005年第5期26卷 587-593页

作者： kamel Hooman Mofid Gorji-Bandpy Mechanical Engineering Department Mazandaran UniversityP.O. Box 484BabolIranMechanical Engineering DepartmentMazandaran UniversityP.O. Box 484BabolIran

The effects of viscous dissipation on thermal entrance heat transfer in a parallel plate channel filled with a saturated porous medium,is investigated analytically on the basis of a Darcy *** case of isothermal boundary is *** local and the bulk temperature distribution along with the Nusselt number in the thermal entrance region were found. The fully developed Nusselt number, independent of the Brinkman number, is found to be 6. It is observed that neglecting the effects of viscous dissipation would lead to the well-known case of internal flows,with Nusselt number equal to 4 93.A finite difference numerical solution is also utilized. It is seen that the results of these two methods, analytical and numerical, are in good agreement.

关键词： heat transfer Nusselt number forced convection porous medium viscous dissipation

Capacity and Fairness Maximization-Based Resource Allocation for Downlink NOMA Networks

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Computers, Materials & Continua 2021年第10期69卷 521-537页

作者： Mohammed abd-Elnaby Department of Computer Engineering College of Computers and Information TechnologyTaif UniversityTaif21944Saudi Arabia

Non-orthogonal multiple access(NOMA)is one of the leading technologies for 5G *** pairing(UP)and power allocation(PA)are the key controlling mechanisms for the optimization of the performance of NOMA *** paper presents a novel UP and PA(UPPA)technique for capacity and fairness maximization in NOMA called(CFM-UPPA).The impact of the power allocation coefficient and the ratio between the channel gains of the paired users on the sum-rate capacity and the fairness in NOMA is firstly ***,based on this investigation,the PA and UP algorithms of the CFM-UPPA technique are *** power allocation coefficient of the proposed PA is formulated as an exponentially decaying function of the ratio between the channel gains of the paired users to maximize the capacity and the fairness,and its maximum value is adjusted to guarantee the successive interference cancellation(SIC)*** proposed UP is based on selecting the user that has the highest channel gain per subcarrier as the strong user to maximize the capacity and selecting the user that has the closest lower channel gain to the strong user’s channel gain as the weak user to improve the fairness and *** performance evaluation of the proposed CFM-UPPA technique in terms of capacity,fairness,and outage probability demonstrates that its performance significantly outperforms that of the orthogonal multiple access(OMA)system and that of the NOMA system with random ***,the simulation results demonstrate the efficiency of the proposed PA in improving the performance of other UP algorithms,such as the random UP algorithm.

关键词： 5G non-orthogonal multiple access user pairing power allocation capacity fairness

Generalized Einstein Tensor for a Weyl Manifold and Its Applications

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Acta Mathematica Sinica,English Series 2013年第2期29卷 373-382页

作者： abdlkadir ZDEGER Kadir Has University Department of Statistics and Computer ScienceCibali Campus

It is well known that the Einstein tensor G for a Riemannian manifold defined by Gα^β = 1/2α^β ,Rα^β=g^α^β γ where Rγα and R are respectively the Ricci tensor and the scalar curvature of the manifold, plays an important part in Einstein s theory of gravitation as well as in proving some theorems in Riemannian geometry. In this work, we first obtain the generalized Einstein tensor for a Weyl manifold. Then, after studying some properties of generalized Einstein tensor, we prove that the conformal invariance of the generalized Einstein tensor implies the conformal invariance of the curvature tensor of the Weyl manifold and conversely. Moreover, we show that such Weyl manifolds admit a one-parameter family of hypersurfaces the orthogonal trajectories of which are geodesics. Finally, a necessary and sufficient condition in order that the generalized circles of a Weyl manifold be preserved by a conformal mapping is stated in terms of generalized Einstein tensors at corresponding points.

关键词： Weyl manifold Einstein-Weyl manifold Einstein tensor generalized Einstein tensor,generalized circle

HCV Therapy Follow-up Fractionation (CTF2) by Intra-PBMC Nested RNA PCR Recognizes Early Virologic Response and Relapse

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Journal of Clinical and Translational Hepatology 2018年第2期6卷 147-154页

作者： Mohamed Darwish Ahmed abd Alla Saleh Ahmed Elibiary Ramy Hassan Elshaboury George Y.Wu Reham M.Dawood Mostafa kamel El Awady Tropical Medicine Department Faculty of MedicineAl-Azhar UniversityCairoEgypt Department of Pharmacy Massachusetts General HospitalBostonMAUSA Department of Medicine Division of Gastroenterology-HepatologyUniversity of Connecticut Health CenterHartfordCTUSA Department of Microbial Biotechnology National Research CenterCairoEgypt

Background and Aims:Sustained virologic response is evaluated by single-step reverse transcription(SRT)PCR as-say,which assesses hepatitis C virus(HCV)clearance from plasma but not from tissues such as peripheral blood mono-nuclear cells(PBMCs).Persistence of HCV RNA in PBMCs beyond end of treatment(EOT)is associated with *** goal was to measure intra-PBMC HCV RNA levels during oral antiviral therapy according to the HCV therapy follow-up fractionation(CTF2)***:Compen-sated chronic HCV patients(n=278 SRT-PCR positive)were scheduled to receive oral antiviral *** were followed-up by SRT and intra-PBMCs HCV RNA PCR at the end of the 2nd,6th,10th,14th,18th and 24th weeks to evaluate virus clearance from plasma and PBMCs,*** CTF2 protocol evaluated SRT and PBMC PCR status at each follow-up point for determining therapy continuation or inter-ruption to address cost ***:All patients tested negative by SRT PCR after therapy for 2 ***-cation of the CTF2 protocol revealed:a)increasing HCV clear-ance rate from 75.9%at the end of 10th week to 90.3%at the end of 24th week(p<0.00001);b)faster clearance of HCV from plasma compared to PBMCs at each point of follow-up until the 18th week(p<0.05);c)higher viral elimination rates diagnosed by PBMC HCV RNA PCR(?)compared to PBMC HCV RNA PCR(+)from the 6th to 24th week of treatment(p<0.0001);d)higher over-time increase curve of combined plasma and PBMC HCV RNA determined negativity compared to the decline in positivity curves by PBMC PCR at the 6th-18th week compared to the 24th week(p<0.01)—these results validated treatment continuation;and e)solitary evaluation of EOT sustained HCV infection and relapses by PBMC HCV RNA(p<0.001).Conclusions:Early elimination of serum and tissue(PBMC)HCV infection by oral antiviral therapy can be achieved and evaluated during a cost-effective CTF2 pro-tocol application.

关键词： CTF2 protocol HCV PBMCs PCR Cost-effectiveness

Ore Controls and Metallogenesis of Au-Ag Deposits at Atalla Mine,Central Eastern Desert of Egypt

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Acta Geologica Sinica(English Edition) 2020年第5期94卷 1451-1470页

作者： Mohamed abd EL MONSEF Geology Department Faculty of ScienceTanta UniversityTanta 31527Egypt Institute of Geological Sciences Faculty of ScienceMasaryk UniversityBrnoCzech Republic

Gold-silver deposits in the Atalla area occur as hydrothermal quartz veins in NE–SW pre-existing fractures within the Atalla granitic *** orientation of such quartz veins has been attributed to extensional behavior related to the Atalla Shear Zone(ASZ).The Atalla area is covered by a variety of lithologies that are(from oldest to youngest):metasedimentary rocks,metavolcanic rocks,ophiolite assemblage(serpentinites/talc-carbonates),Atalla granite and Dokhan volcanic ***,Atalla granite ranges in composition from granodiorite to *** geochemistry constrains the calc-alkaine affinity of the Atalla granite that was intruded within an orogenic(syncollision)tectonic *** ore minerals are represented by gold/silver(electrum),pyrite(Py1&Py2),arsenopyrite,pyrrhotite,sphalerite,chalcopyrite,galena,covellite and *** temperature of ore formation ranges from 240 to 285℃and the estimated fluid pressure is in the range of 20–100 *** on the geological setting,ore textures and fluid characteristics;the Atalla Au-Ag deposits are considered to be orogenic in nature,formed from a continental collision(~653-590 Ma),synchronous with the emplacement of calc-alkaline magmatism during the evolutionary history of the Arabian Nubian Shield(ANS).The initial ore-forming fluid was primarily derived from a metamorphic source related to ophiolitic-serpentinite rocks under deep regional conditions of greenschist-amphibolite facies,where the Atalla granitic eruption provided the required temperature conditions for the metamorphic process to take *** such conditions,the transportation of ore metals as bisulfide complexes is *** deposition of ore minerals was triggered by fluidwallrock interaction through fracture pathways in conjunction with a temperature-pressure drop that is likely to have been related to uplift into the crustal levels.

关键词： Gold-silver arsenopyrite geothermometry fluid inclusions orogenic deposits Atalla Shear Zone(ASZ)

Effect of Cyclic Stress Reduction on the Creep Characteristics of AZ91 Magnesium Alloy

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Acta Metallurgica Sinica(English Letters) 2015年第8期28卷 1065-1073页

作者： Alaa Farag abd El-Rehim Physics Department Faculty of Science King Khalid University Physics Department Faculty of Education Ain Shams University

The creep deformation behavior of aged AZ91 magnesium alloy under the cyclic stress reduction has been investigated in the temperature range 353–383 K. The microstructural evolution of the AZ91 magnesium alloy at different heat treatment conditions has been studied using optical microscopy and scanning electron microscopy. The minimum strain rate, e_min, was found to be higher under cyclic stress reduction condition than that under static creep condition for the same maximum stress. Cyclic creep acceleration is interpreted using the interaction of moving dislocations with the existing b-phase（Mg17Al12） precipitates. The mean value of the activation energy of secondary creep stage was found to be equal to that quoted for lattice self-diffusion of magnesium mechanism.

关键词： Magnesium alloys Microstructure Cyclic stress Dislocations

ON THE FINITE MELLIN TRANSFORM IN QUANTUM CALCULUS AND APPLICATION

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Acta Mathematica Scientia 2018年第4期38卷 1393-1410页

作者： Bochra NEFZI kamel BRAHIM Ahmed FITOUHI Faculty of Sciences of Tunis University of Tunis El Manar

The aim of the present paper is to introduce and study a new type of q-Mellin transform [11], that will be called q-finite Mellin transform. In particular, we prove for this new transform an inversion formula and q-convolution product. The application of this transform is also earlier proposed in solving procedure for a new equation with a new fractional differential operator of a variational type.

关键词： q-Mellin transform finite Mellin transform fractional q-integral fractionalq-differential equation

Piecewise Smooth Dynamical Systems Modeling Based on Putzer and Fibonacci-Horner Theorems:DC-DC Converters Case

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International Journal of Automation and computing 2016年第3期13卷 246-258页

作者： abdelkader Khoudiri kamel Guesmi Djillali Mahi Department of Sciences and Techniques Djelfa University CRe STIC IUT de Troyes

The paper deals with the problem of switched dynamical systems modeling especially in DC-DC converters case study consideration. It presents two approaches to describe accurately the behavior of this class of systems. To clarify the paper＇s contribution, the proposed approaches are validated through simulations and experimental results. A comparative study, between the obtained results and those of other techniques from the literature, is given to evaluate the performances of the studied approaches.

关键词： Switched systems DC-DC converters modeling Cayley-Hamilton theorem Putzer's theorem Fibonacci-Horner decom-position theorem.

A Comparative Analysis on Surgical Outcomes and Complications of Endoscopic and Open Vein Harvesting Techniques

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Open Journal of Thoracic Surgery 2024年第2期14卷 29-39页

作者： Mohammed Fawzy Eltaweel Ismail N. El-Sokkary Ahmed Alherazi Mohamed Wael Badawi Mohammed G. abdellatif Bahaa A. Elkhonezy Ibrahim K. Gamil Haytham Mohamed abd El Moaty Sarra Sadmi Mahmoud Khalil Department of Cardiothoracic Surgery Faculty of Medicine Menoufia University Shibin El Kom Egypt Department of Cardiovascular & Thoracic Surgery Faculty of Medicine Al-Azhar University Cairo Egypt Department of Cardiothoracic Surgery Faculty of Medicine Alexandria University Alexandria Egypt Faculty of Medicine University of Algiers Algiers Algeria Department of Cardiac Surgery Sabah Al-Ahmed Cardiac Center Al-Amiri Hospital Kuwait City Kuwait

Objective: The great saphenous vein (GSV) is commonly used as a conduit for grafting during CABG surgery, and open GSV harvesting (OVH), commonly used with long incision to expose the vein. However, endoscopic vein harvesting (EVH) is an alternative approach, utilizing specialized instruments and small incisions to harvest the vein. Methods: A retrospective analysis was conducted on a cohort of patients who underwent Coronary artery bypass graft (CABG) requiring great saphenous vein (GSV) harvesting which was done by EVH or OVH procedures. Demographic variables, including age and gender, were assessed for both groups. Intraoperative variables such as the number of grafts, cardiopulmonary bypass time, X clamp time, and type of procedure were analyzed. Postoperative variables, including infection and bleeding rates, were also evaluated. Results: The study included 30 patients each undergoing Coronary artery bypass graft (CABG) with need of great saphenous vein harvesting which was done by EVH and OVH. Demographic variables were well-matched between the two groups in terms of age, while a significant difference in gender distribution was observed. Obesity and smoking were more prevalent in the OVH group, and EVH was associated with a higher mean number of grafts compared to OVH. Conversion to an open technique occurred in a portion of the EVH cases, and infection rates did not significantly differ between the EVH and OVH groups. However, the incidence of postoperative bleeding was significantly higher in the EVH group. Conclusion: This study provides valuable insights into the demographic, intraoperative, and postoperative variables associated with EVH and OVH techniques. EVH demonstrated advantages in terms of reduced infection rates compared to OVH. However, the higher incidence of postoperative bleeding associated with EVH raises concerns about potential risks.

关键词： Endoscopic Vein Harvesting (EVH) Open Vein Harvesting (OVH) Coronary Artery Bypass Grafting (CABG) Great Saphenous Vein (GSV) Surgical Outcomes