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A New Approach for Manufacturing a high Porosity Ti-6Al-4V scaffolds for Biomedical Applications

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Journal of Materials science & Technology 2008年第6期24卷 931-935页

作者： Montasser DEWIDAR h.Fouad mohamed Jae-Kyoo LIM Department of Mechanical Design and Materials High Institute of EnergySouth Valley University AswanEgypt Biomedical Engineering Department Faculty of EngineeringHelwan UniversityEgypt Automobile hi-Technology Research Institute Faculty of Mechanical & Aerospace System Eng.Chonbuk National UniversityDuckjin 1-664-14JeonjuJB 561-756South Korea

Titanium and its alloys are currently considered as one of the most important metallic materials used in the biomedical applications, due to their excellent mechanical properties and superior biocompatibility. In the present study, a new effective method for fabricating high porosity titanium alloy scaffolds was developed. Porous Ti-6Al-4V scaffolds are successfully fabricated with porosities ranging from 30% to 70% using spaceholder and powder sintering technique. Based on its acceptable properties, spherical carbamide particles with different diameters （0.56, 0.8, and 1mm） were used as the space-holder material in the present investigation. The Ti-6Al-4V scaffolds porosity is characterized by using scanning electron microscopy. The results show that the scaffolds spherical-shaped pores are depending on the shape, size and distribution of the space-holder particles. This investigation shows that the present new manufacturing technique is promising to fabricate a controlled high porosity and high purity Ti-6Al-4V scaffolds for hard tissue replacement.

关键词： Ti-6Al-4V Porous material Powder metallurgy space-holder

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A simulation-based method to investigate occupant-centric controls

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Building simulation 2021年第4期14卷 1017-1030页

作者： mohamed M.Ouf June Young Park h.Burak Gunay Department of Building Civil and Environmental EngineeringConcordia University1515Rue Sainte-Catherine O.MontrealQCH3G 1MCanada Department of Civil Engineering The University of Texas at ArlingtonArlingtonTX76019USA Department of Civil Engineering Carleton University1125 Colonel By DriveOttawaONK1S 5B6Canada

Occupant-centric control (OCC) strategies rely on different algorithms to learn and predict occupants’ patterns and preferences, then utilize these predictions to optimize building operations. however, testing different OCC algorithms or fine-tuning their configurations in real buildings can be a lengthy process. To this end, we present a framework for testing OCCs in a simulation environment prior to field implementation. The proposed workflow entails using synthetic occupant behaviour models and simulating OCC strategies to learn their preferences. The goal is to enable quick comparison of different OCC configurations under various scenarios by modifying occupant behaviour assumptions, as well as climate and design parameters. For proof-of-concept, the proposed method was applied in a case-study to simulate OCCs for lighting and heating/cooling setpoint adjustments in a single office under various occupant types, as well as OCC settings and design configurations. Results demonstrated the benefits of the proposed framework and its potential for providing a more holistic evaluation of OCCs under different scenarios. Using the proposed framework, building designers and operators can identify potential issues with OCCs and fine-tune their settings prior to field implementation.

关键词： occupant-centric controls building simulations energy efficiency comfort building operations lighting hVAC controls

Frequency of diabetic retinopathy and associated risk factors in Khartoum,sudan:population based study

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International Journal of Ophthalmology(English edition) 2017年第6期10卷 948-954页

作者： Einas s Elwali Ahmed O Almobarak Mona A hassan Amir A Mahmooud heitham Awadalla mohamed h Ahmed Department of Medicine and hIV Metabolic Clinic Milton Keynes University Hospital NHS Foundation Trust Eaglestone Milton Keynes Buckinghamshire MK 6 5LD UK

AIM： To assess the frequency and associated risk fac- tors of diabetic retinopathy among sudanese individuals with diabetes attending Makka Eye complex in Khartoum, sudan. METhODs： The cross sectional hospital based study recruited 316 individuals with diabetes from Makkah Eye Complex Retina Clinic. standard questionnaire was used to collect demographic data, medical history and life style characteristics. Blood samples were taken to measure hbAlc and lipid profile. Fundus and slit lamp examination were performed for screening of diabetic retinopathy. REsULTs： Among 316 participants, 187 （59.2%） were males and 129 （40.8%） were females. The mean age of participants was 58.7＋_10.5y. The overall frequency of retinopathy was 261 （82.6%）. The percentages of the total participants with proliferative diabetic retinopathy （PDR） were 126 （39.9%） and non-proliferative diabetic retinopathy （NPDR） were 135 （42.7%）. importantly, duration of diabetes mellitus （DM）（72.2% of more than 10y）, being on oral hypoglycaemic drugs （versus insulin）, and hypertension were all significant risk factors for diabetic retinopathy （P=0.00, 0.01 and 0.00 respectively）. Complications ofdiabetes like diabetic foot （17.7%）, history of amputation （6.7%） and clinically significant macular edema （CsME）（47.4%） of the eyes were all significant risk factors （P〈0.05）. Logistic regression analysis showed that duration of diabetes, hypertension and CsME were found to be absolute risk factors （P=-0.007, 0.003 and 0,000 respectively）. Duration of DM of more than 10y have more than double risk （OR--2.8）, while having hypertension triples the risk of retinopathy （OR=3.1）. CONCLUsION： high rates of diabetic retinopathy are noted among individuals with diabetes attending Makkah Eye hospital in capital Khartoum. Urgent strategies are needed to monitor and treat hypertension and optimize diabetes control in individuals with diabetes. More investment in diabetes services is urgently needed.

关键词： diabetes sudan diabetic retinopathy insulin

New Polymer syntheses Part 60: A Facile synthetic Route to Polyamides Based on Thieno[2,3-b]thiophene and Their Corrosion Inhibition Behavior

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Chinese Journal of Polymer science 2018年第7期36卷 835-847页

作者： Kamal I.Aly Amr h.Moustafa Essam K.Ahmed hany M.Abd El-lateef mohamed Gamal mohamed sahar M.mohamed Polymer Research Lab Chemistry Department Faculty of Science Assiut University Chemistry Department Faculty of Science Sohag University Chemistry Department Faculty of Science Minia University Chemistry Department College of Science King Faisal university

Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer la with different kinds of diacid chlorides （including oxalyl, adipoyl, sebacoyl, isophthaloyl, terephthaloyl, 4,4＇-azodibenzoyl, 3,3＇-azodibenzoyl, p-phenylene diacryloyl） in the presence of LiC1 and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy （including 1 h-NMR and 13 C-NMR） and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis （TGA）, wide-angle X-ray diffraction analysis （WAXD） and scanning electron microscopy （sEM）. Also, the corrosion inhibition behavior of selected examples ofpolyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol＇L-1 hCI was studied using potentiodynamic polarization （PDP） and electrochemical impedance spectroscopy （EIs） methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency （P, %） was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer. The adsorption of these polymers was found to obey Langmuir adsorption isotherm.

关键词： Thieno[2 3-b]thiophene Polymer synthesis Thermal properties Industrial applications Corrosion inhibition

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Terlipressin and hepatorenal syndrome: What is important for nephrologists and hepatologists

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World Journal of Gastroenterology 2010年第41期16卷 5139-5147页

作者： Ahmed A Magan Atif A Khalil mohamed h Ahmed Department of surgery Cambridge Uni-versity Hospital NHS foundation Trust Hills Road Cambridge CB2 0QQ United Kingdom Department of Nephrology Royal Liverpool and Broadgreen University Hospitals Liverpool L7 8XP United Kingdom Division of Acute Medicine James Cook University Hospital Marton Road Middlesbrough TS4 3BW United Kingdom

hepatorenal syndrome (hRs) is a reversible form of functional renal failure that occurs with advanced hepatic cirrhosis and liver failure. Despite mounting research in hRs, its etiology and medical therapy has not been resolved. hRs encompasses 2 distinct types. Type 1 is characterized by the rapid development of renal failure that occurs within 2 wk and involves a doubling of initial serum creatinine. Type 2 has a more insidious onset and is often associated with ascites. Animal studies have shown that both forms, in particular type 1 hRs, are often precipitated by bacterial infections and cir-culatory changes. The prognosis for hRs remains very poor. Type 1 and 2 both have an expected survival time of 2 wk and 6 mo, respectively. Progression of liver cir-rhosis and the resultant portal hypertension leads to the pooling of blood in the splanchnic vascular bed. The ensuing hyperdynamic circulation causes an ineffective circulatory volume which subsequently activates neuro-hormonal systems. Primarily the sympathetic nervoussystem and the renin angiotensin system are activated, which, in the early stages of hRs, maintain adequate circulation. Both advanced cirrhosis and prolonged ac-tivation of neurohormonal mechanisms result in fatal complications. Locally produced nitric oxide may have the potential to induce a deleterious vasodilatory effect on the splanchnic circulation. Currently medical therapy is aimed at reducing splanchnic vasodilation to resolve the ineffective circulation and maintain good renal per-fusion pressure. Terlipressin, a vasopressin analogue, has shown potential benefit in the treatment of hRs. It prolongs both survival time and has the ability to re-verse hRs in the majority of patients. In this review we aim to focus on the pathogenesis of hRs and its treatment with terlipressin vs other drugs.

关键词： heptorenal syndrome Terlipressin Kidney Liver

Multiphysics simulation of VVER-1200 fuel performance during normal operating conditions

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Nuclear science and Techniques 2023年第2期34卷 139-152页

作者： Khaled M.Yassin mohamed h.hassan Mohammad M.Ghoneim Mostafa s.Elkolil Adel Alyan said A.Agamy Nuclear Research Center Egyptian Atomic Energy AuthorityAbo Zaabal 13759CairoEgypt Department of Nuclear and Radiological Engineering Faculty of EngineeringAlexandria UniversityAlexandria 21544Egypt Faculty of Engineering Egyptian Russian UniversityBadr 11829Egypt

Nuclear fuel performance modeling and simulation are critical tasks for nuclear fuel design optimization and safety analysis under normal and transient *** performance is a complicated phenomenon that involves thermal,mechanical,and irradiation mechanisms and requires special multiphysics *** this study,a fuel performance model was developed using the COMsOL Multiphysics *** modeling was performed for a 2D axis-symmetric geometry of a UO2fuel pellet in the E110 clad for VVER-1200 *** modeling considers all relevant phenomena,including heat generation and conduction,gap heat transfer,elastic strain,mechanical contact,thermal expansion,grain growth,densification,fission gas generation and release,fission product swelling,gap/plenum pressure,and cladding thermal and irradiation *** model was validated using a code-to-code evaluation of the fuel pellet centerline and surface temperatures in the case of constant power,in addition to validation of fission gas release(FGR)*** prediction proved that the model could perform according to previously published VVER nuclear fuel performance parameters.A sensitivity study was also conducted to assess the effects of uncertainty on some of the model *** model was then used to predict the VVER-1200 fuel performance parameters as a function of burnup,including the temperature profiles,gap width,fission gas release,and plenum pressure.A compilation of related material and thermomechanical models was conducted and included in the modeling to allow the user to investigate different material/performance *** the model was developed for normal operating conditions,it can be modified to include off-normal operating conditions.

关键词： VVER-1200 Fuel performance COMsOL code Zr-1%Nb cladding UO2 fuel rod

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Fabrication, modification and environmental applications of TiO2 nanotube arrays （TNTAs） and nanoparticles

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Frontiers of Chemical science and Engineering 2012年第1期6卷 112-122页

作者： s. ROhANI T. IsIMJAN A. mohamed h. KAZEMIAN M. sALEM T. WANG Department of Chemical and Biochemical Engineering The University of Western Ontario London N6A 5B9 Canada

Among the semiconductors, titanium dioxide has been identified as an effective photocatalyst due to its abundance, low cost, stability, and superior electronic energy band structure. highly ordered nanotube arrays of titania were produced by anodization and mild sonication. The band gap energy of the titania nanotube arrays was reduced to 2.6 eV by co-doping with Fe, C, N atoms using an electrolyte solution containing K3Fe（CN）6. The photo- conversion of phenol in a batch photoreactor increased to more than 18% based on the initial concentration of phenol by using a composite nanomaterial consisting of titania nanotube arrays and Pt/ZIF-8 nanoparticles. A layer-by- layer assembly technique for the deposition of titania nanoparticles was developed to fabricate air filters for the degradation of trace amounts of toluene in the air and preparation of superhyrophobic surfaces for oil-water separation and anti-corrosion surfaces.

关键词： TiO2 nanotube arrays and nanoparticles,anodization bandgap modification layer-by-layer deposi-tion oil-water separation

sediment balances in the Blue Nile River Basin

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International Journal of sediment Research 2014年第3期29卷 316-328页

作者： Yasir s.A.ALI Alessandra CROsATO Yasir A.mohamed seifeldin h.ABDALLA Nigel G.WRIGhT UNEsCO-IhE Westvest 72601 DA Delftthe Netherlands and Hydraulics Research CenterMinistry of Water Resources and ElectricityP.O.Box 318Wad MedaniSudan UNEsCO-IhE Westvest 72601 DA Delft and Profat Hydraulics Research CenterMinistry of Water Resources and Electricity school of Civil Engineering University of LeedsFaculty of EngineeringLeeds LS2 9JT.United Kingdom Water Resources Technical Organ Ministry of Water Resources and ElectricityKhartoumSudan UNEsCO-IhE Westvest 72601 DA Delft and Research Associate at Civil Engineering and Geosciences Delft University of TechnologyStevin weg 12628 CN Delftthe Netherlands

Rapid population growth in the upper Blue Nile basin has led to fast land-use changes from natural forest to agricultural *** resulted in speeding up the soil erosion process in the highlands and increasing sedimentation further downstream in reservoirs and irrigation *** present,several dams are planned across the Blue Nile River in Ethiopia and the Grand Ethiopian Renaissance Dam is currently under construction near the border with *** will be the largest hydroelectric power plant in *** objective of this paper is to quantify the river flows and sediment loads along the Blue Nile River *** soil and Water Assessment Tool was used to estimate the water flows from un-gauged *** assess model performance,the estimated sediment loads were compared to the measured ones at selected *** the gauged sub-basins,water flows and sediment loads were derived from the available flow and sediment *** fill in knowledge gaps,this study included a field survey in which new data on suspended solids and flow discharge were collected along the Blue Nile and on a number of *** comparison between the results of this study and previous estimates of the sediment load of the Blue Nile River at El Deim,near the Ethiopian sudanese border,show that the sediment budgets have the right order of magnitude,although some uncertainties *** gives confidence in the results of this study providing the first sediment balance of the entire Blue Nile catchment at the sub-basin scale.

关键词： Blue Nile basin sediment balance Field data Rating curve sWAT model

Covid-19 Detection Using Deep Correlation-Grey Wolf Optimizer

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Computer systems science & Engineering 2023年第9期46卷 2933-2945页

作者： K.s.Bhuvaneshwari Ahmed Najat Ahmed Mehedi Masud samah h.Alajmani mohamed Abouhawwash Department of Computer science and Engineering Karpagam College of EngineeringCoimbatore641032India Department of Computer Engineering Lebanese French UniversityErbil44001Iraq Department of Computer science College of Computers and Information TechnologyTaif UniversityP.O.Box 11099Taif21944Saudi Arabia Department of Information Technology College of Computer and Information TechnologyTaif UniversityPO Box 11099Taif21994Saudi Arabia Department of Mathematics Faculty of ScienceMansoura UniversityMansoura35516Egypt Department of Computational Mathematics Scienceand Engineering(CMSE)Michigan State UniversityEast Lansing48824MIUSA

The immediate and quick spread of the coronavirus has become a life-threatening disease around the *** widespread illness has dramatically changed almost all sectors,moving from offline to online,resulting in a new normal lifestyle for *** impact of coronavirus is tremendous in the healthcare sector,which has experienced a decline in the first quarter of *** pandemic has created an urge to use computer-aided diagnosis techniques for classifying the Covid-19 dataset to reduce the burden of clinical *** current situation motivated me to choose correlationbased development called correlation-based grey wolf optimizer to perform accurate classification.A proposed multistage model helps to identify Covid from Computed Tomography(CT)scan *** first process uses a convolutional neural network(CNN)for extracting the feature from the CT *** Pearson coefficient filter method is applied to remove redundant and irrelevant ***,theGrey wolf optimizer is used to choose optimal *** analysis proves that this determines the optimal characteristics to detect the deadly *** proposed model’s accuracy is 14%higher than the krill herd and bacterial foraging optimization for severe accurate respiratory syndrome image(sARs-CoV-2 CT)*** COVID CT image dataset is 22%higher than the existing krill herd and bacterial foraging optimization *** proposed techniques help to increase the classification accuracy of the algorithm in most cases,which marks the stability of the stated *** analysis reveals that the proposed classification technique to predict COVID-19 withmaximumaccuracy of 98%outperforms other competitive approaches.

关键词： COVID-19 feature selection CT image classification features extraction