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Microstructure and mechanical properties of.hot extruded 6016 aluminum alloy/graphite composites

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Journal of.Materials Science & Technology 2018年第9期34卷 1580-1591页

作者： Mohamed M.el-Sayed Seleman Mohamed M.z.Ahmed Sabbah Ataya Department of.Metallurgical and Materials Engineering Faculty of Petroleum and Mining Engineering Suez University 43518 Suez Egypt Suez.and Sinai Metallurgical and Materials Research Center of.Scientif.c Excellence (SSMMR-CSE) 43518 Suez Egypt The British University in Egypt Mechanical Engineering Deportment El-Sherouk City 11837 Cairo Egypt Department of.Mechanical Engineering College of Engineering AI Imam Mohammad Ibn Saud Islamic University Riyadh 11432 saudi Arabia

The incorporation of.graphite particles into AA6016 aluminum alloy matrix to f.bricate metal/ceramic composites is still a great challenge and various parameters should be considered. In this study, dense AA6016 aluminum alloy/（0-20 wt%） graphite composites have successf.lly been f.bricated by powder metallurgy process. At f.rst, the mixed aluminum and graphite powders were cold compacted at 200 MPa and then sintered at 500 ℃ f.r 1 h f.llowed by hot extrusion at 450 ℃. The inf.uence of.ceramic phases（f.ee graphite and in-situ f.rmed carbides） on microstructure, physical and mechanical properties of.the produced composites were f.nally investigated. The results show that the f.bricated composites have a relative density of.over 98%. SEM observations indicate that the graphite has a good dispersion in the alloy matrix even at high graphite content. Hardness of.all the produced composites was higher than that of.aluminum alloy matrix. No cracks were observed at strain less than 23% f.r all hot extruded *** strength, reduction in height, ultimate tensile stress, f.acture stress, yield stress, and f.acture strain of.all Al/graphite composites were determined by high precision second order equations. Both compressive and ultimate tensile strengths have been correlated to microstructure constituents with f.cusing on the in-situ f.rmed ceramic phases, silicon carbide（SiC） and aluminum carbide（Al4 C3）. The ductile f.acture mode of.the produced composites became less dominant with increasing f.ee graphite content and in-situ f.rmed carbides. Wear resistance of.Al/graphite composites was increased with increasing graphite content. Aluminum/20 wt% graphite composite exhibited superior wear resistance over that of.AA6016 aluminum alloy.

关键词： AA6016/graphite composites Hot extrusion In-situ carbides Mechanical properties Wear resistance f.acture behavior

In situ modif.d screen printed and carbon paste ion selective electrodes f.r potentiometric determination of.naphaz.line hydrochloride in its f.rmulation

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Journal of.Pharmaceutical Analysis 2013年第5期3卷 367-375页

作者： Gehad G.Mohamed f.A.Nour el-Dien Eman Y.z.f.ag Marwa el-Badry Mohamed Chemistry Department Faculty of Science Cairo University

The construction and perf.rmance characteristics of.new sensitive and selective in situ modif.ed screen printed （ISPE） and carbon paste （ICPE） electrodes f.r determination of.naphaz.line hydrochloride （NPz.HC1） have been developed. The electrodes under investigation show potentiometric response f.r NPz.HC1 in the concentration range f.om 7.0 x 10-7 to 1.0 x 10-2 M at 25 ~C and the electrode response is independent of.pH in the range of.3.1-7.9. These sensors have slope values of.59.7＋0.6 and 59.2＋0.2 mV decade-l with detection limit values of.5.6 ~ 10-7 and 5.9 x 10-7 M NPz. HC1 using ISPE and ICPE, respectively. These electrodes show f.st response time of.4-7 s and 5-8 s and exhibits lif.times of.28 and 30 days f.r ISPE and ICPE, respectively. Selectivity f.r NPz.HC1 with respect to a number of.interf.ring materials was also investigated. It was f.und that there is no interf.rence f.om the investigated inorganic cations, anions, sugars and other pharmaceutical excipients. The proposed sensors were applied f.r the determination of.NPz.HC1 in pharmaceutical f.rmulation using the direct potentiometric method. It showed a mean average recovery of.100.2% and 102.6% f.r ISPE and ICPE, respectively. The obtained results using the proposed sensors were in good agreement with those obtained using the of.icial method. The proposed sensors show signif.cantly high selectivity, response time, accuracy, precision, limit of.detection （LOD）and limit of.quantif.cation （LOQ） compared with other proposed methods.

关键词： ISPE and ICPE Potentiometry Naphaz.line hydrochloride Eye drops

Sesamol Alleviates the Cytotoxic Ef.ect of.Cyclophosphamide on Normal Human Lung WI-38 Cells via Suppressing RAGE/Nf.κB/Autophagy Signaling

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Natural Products and Bioprospecting 2021年第3期11卷 333-343页

作者： Soad z.el-Emam Department of.Pharmacology and Toxicology Faculty of PharmacyOctober 6 University6 October CityGiza 12566Egypt

Cyclophosphamide(CYL)is a chemotherapeutic medication commonly used in managing various malignancies like breast cancer or ***,CYL has been documented to induce lung *** of.CYL toxicity is through oxidative stress and the release of.damage-associated molecular patterns(DAMPs).Sesamol(SES)is a natural antioxidant isolated f.om Sesamum indicum and its ef.ect against CYL-induced lung toxicity is not studied *** study aims to inves-tigate whether SES could prevent any deleterious ef.ects induced by CYL on lung using normal human lung cells,WI-38 cell line,without suppressing its *** were pretreated with SES and/or CYL f.r 24 h,then cell viability was estimated by MTS and trypan blue *** mode of.cell death was determined by AO/EB ***,caspase-3 level,oxidative stress,and inf.ammatory markers were evaluated by colorimetric and elISA ***-PCR was perf.rmed to evaluate RAGE,Nf.κB,and Beclin-1 ***-treated WI-38 cells developed a signif.cantly increased cell death with enhanced oxidative and RAGE/Nf.κb/Autophagy signaling,which were all attenuated af.er pretreatment with ***,we concluded that SES of.ered a protective role against CYL-induced lung injury via suppressing oxidative stress and RAGE/Nf.κB/Autophagy signaling,which is a natural saf. therapeutic option against CYL toxicities.

关键词： Cyclophosphamide Sesamol Lung toxicity Autophagy Oxidative stress RAGE

Evaluation of.the Crustal f.atures of.the Gulf.of.Aqaba Deduced f.om Geophysical Data

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Journal of.Geoscience and Environment Protection 2019年第4期7卷 26-41页

作者： A. z. Hamouda S. el-Gharabawy Marine Geophysics Lab National Institute of Oceanography and Fisheries Alexandia Egypt

The Gulf.of.Aqaba is considered as an interesting rif. system. Theref.re, it is important to understand the crustal f.atures and thickness variation along the Gulf.to be able to evaluate the ef.ect of.tectonic activities in shaping the Gulf. The obtained data were used to estimate the reliable empirical relations between the Bouguer anomalies (ΔgB) and crustal thickness (Hc) in the Gulf.of.Aqaba. This equation was used to calculate the depth relief. to the Moho boundary. The output map of.the Moho relief.and the corresponding crustal thickness were constructed f.r the Gulf.of.Aqaba. The depth f.om sea level down to the Moho discontinuity in the Gulf.of.Aqaba varies between about 37 km in the northern deep and abruptly changes to about 28 km at the southern area, Tiran Strait. Below the central part of.the gulf. a Moho depth of.about 34 km is obtained. The Red Sea crust is thinner than that of.the Dead Sea rif.;indicating the presence of.a mantel upwelling that is related to the spreading of.the sea f.oor. The asymmetry of.crustal thickness between the eastern and western borders of.the Gulf.of.Aqaba could be attributed to simultaneous strike-slip motion. The relative displacement between the two borders is observed clearly through the sea f.oor and Moho discontinuity. The displacement is nearly equivalent to 0.18° (i.e. about 20.4 km) and is assumed to be achieved in about 4.08 to 3.4 million years, according to the estimated rate of.the transf.rm motion along the Gulf.of.Aqaba (Dead Sea transf.rm) that is about 0.5 to 0.6 cm/y.

关键词： Gulf of Aqaba Bouguer Map Bathymetry Crustal Thickness Moho Discontinuity Tectonics Activity Red Sea

Exact Solutions of.f.actional-Order Biological Population Model

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Communications in Theoretical Physics 2009年第12期52卷 992-996页

作者： A.M.A.el-Sayed S.z.Rida A.A.M.Araf. Department of.Mathematics Faculty of ScienceAlexandria University Department of.Mathematics Faculty of ScienceSouth Valley University

In this paper, the Adomian＇s decomposition method （ADM） is presented f.r f.nding the exact solutions of.a more general biological population models. A new solution is constructed in power series. The f.actional der... 详细信息

关键词： biological populations model f.actional Calculus decomposition method Mittag-Lef.ier f.nction

The intensity of.slope and f.uvial processes af.er a catastrophic windthrow event in small catchments in the Tatra Mountains

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Journal of.Mountain Science 2021年第6期18卷 1405-1423页

作者： Dariusz.STRz.ŻOWSKI elżbieta GORCz.CA Kaz.mierz.KRz.MIEŃ Mirosław ŻelAz.Y Institute of.Geography and Spatial Management Jagiellonian UniversityGronostajowa 7Kraków 30-387Poland

Strong wind events f.equently result in creating large areas of.windthrow, which causes abrupt environmental changes. Bare soil surf.ces within pits and root plates potentially expose soil to erosion. Absence of.f.rest may alter the dynamics of.water circulation. In this study we attempt to answer the question of.whether extensive windthrows inf.uence the magnitude of.geomorphic processes in 6 small second-to third-order catchments with area ranging f.om 0.09 km^(2) to 0.8 km^(2). Three of.the catchments were signif.cantly af.ected by a windthrow which occurred in December 2013 in the Polish part of.the Tatra Mountains, and the other three catchments were mostly f.rested and served as control catchments. We mapped the pits created by the windthrow and the linear scars created by salvage logging operations in search of.any signs of.erosion within them. We also mapped all post-windthrow landslides created in the windthrow-af.ected catchments. The impact of.the windthrow on the f.uvial system was investigated by measuring a set of.channel characteristics and determining bedload transport intensity using painted tracers in all the windthrow-af.ected and control catchments. Both pits and linear scars created by harvesting tend to become overgrown by vegetation in the f.rst several years af.er the windthrow. The only signs of.erosion were observed in 10% of.the pits located on convergent slopes. During the period f.om the windthrow event in 2013 until 2019, 5 very small(total area f.bedload transport was similar(t-test, p=0.05) in most of.the windthrow-af.ected and control catchments. The mapping of.channels revealed many cases of.root plates f.llen into a channel and pits created near a channel. A signif.cant amount of.woody debris delivered into the channels inf.uenced the activity of.f.uvial processes by creating alternating z.nes of.erosion and accumulation.

关键词： f.uvial processes Slope processes Windthrow Tree uprooting Channel morphology Tatra Mountains

GIS and Intra-Site Spatial Analyses: An Integrated Approach f.r Recording and Analyz.ng the f.ssil Deposits at Casablanca Prehistoric Sites (Morocco)

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Journal of.Geographic Inf.rmation System 2011年第4期3卷 373-381页

作者： R. Gallotti A. Mohib M. el Graoui f. z. Sbihi-Alaoui J.-P. Raynal 不详

The Mio-Plio-Pleistocene sequence at Casablanca, covering the last six million years, is well known in scientif.c literature. The variability and the chronology of.the Acheulian sequence is documented by systematic, modern and controlled investigations in various sites (Unit L and Hominid Cave at Thomas I Quarry, Rhinoceros Cave at Oulad Hamida 1 Quarry, Sidi Abderrahman Extension Quarry, Bear’s Cave and Cap Chatelier at Sidi Abderrahman Quarry) which have taken place within the f.amework of.the f.anco-Moroccan co-operative project “Casablanca”. In order to manage the excavation data and to explore the taphonomic nature of.Unit L, Hominid Cave and Rhinoceros Cave, where research is still in progress, an approach combining a Geographic Inf.rmation System (GIS) and spatial analysis techniques was developed, incorporating all existing inf.rmation produced f.om previous excavations and recent surveys of.the sites. The amalgamation of.this data into a GIS has resulted in a digital database that allows the production of.simultaneous or separate visualiz.tions and analyses of.the f.ssils, artif.cts and geological materials within their original spatial contexts and also permits intra-site spatial analyses that allow a comprehensive investigation of.the site f.rmation processes.

关键词： Morocco Casablanca Prehistoric Archaeology GIS Intra-Site Spatial Analyses Site f.rmation Processes

Involvement of.Quebracho tannins in diet alters productive and reproductive ef.iciency of.postpartum buf.alo cows

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Animal Nutrition 2019年第1期5卷 80-86页

作者： Sobhy M.A.Sallam Marwa f.A.Attia Adel N.M.Nour el-Din Samir z.el-z.rkouny Adel M.Saber Hani M.el-z.iat Moustaf. M.z.itoun Department of.Animal and f.sh Production Faculty of AgricultureAlexandria University Animal Production Research Institute Agricultural Research CenterDokki

This study was conducted to investigate the ef.ects of.10 weeks supplementation of.Quebracho tannins(QT; 0 [control], 100 [QT100] or 200 g/[cow$d] [QT_(200)]) to 30 multiparous postpartum buf.alo cows(10 cows per group) on milk yield and composition, blood metabolites and reproductive *** of.QT100 had no signif.cant ef.ect on milk yield, whereas QT_(200) decreased(P els decreased(P f.t-corrected milk(f.M)yield, but no signif.cant ef.ects were f.und on percentages of.milk f.t and protein. Contrariwise, yields of.milk f.t, lactose and milk protein were decreased(P f.t(SNf. percentage and yield were decreased(P f.ovarian f.llicles, number of.small f.llicles, peripheral progesterone concentration and conception rate. Supplementation of.QT_(200) numerically increased number of.large f.llicles, mean diameter of.large f.llicle, number and diameters of.corpora lutea. The inclusion of.QT_(200) shortened days open(DO) and decreased number of.services per ***, QT did not show signif.cant ef.ects on serum total protein, albumin, globulin, glucose,cholesterol and triglycerides concentrations. Supplementation of.QT100 caused an increase(P f.serum urea compared with that in control and QT_(200) groups. Generally, QT decreased(P f.re, the supplementation of.a commercial QT to early lactating Egyptian buf.alo cows displayed negative consequences on their productive and reproductive perf.rmances.

关键词： Buf.alo Tannins Milk traits Blood metabolites Ovarian f.llicles Conception rate

Hospital bed capacity across in Tunisia hospital during the f.rst 4 waves of.the COVID-19 pandemic:A descriptive analysis

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Inf.ctious Medicine 2023年第2期2卷 112-121页

作者： Slimane BenMiled Chiraz.Borgi Mohamed Hsairi Naouf.l Somrani Amira kebir Bio-(Inf.rmatic Mathematics and Statistic)BIMS-Lab LR09-IPT16Institut Pasteur de TunisUniversity of Tunis el ManarTunis 1002Tunisia Ministry of.Health Tunis 1002Tunisia Department of.Epidemiology and Preventive Medicine Faculty of MedecinTunis El Manar UniversityTunis 1002Tunisia IPEIT University of TunisTunis 1002Tunisia

Background:In March 2020,the WHO declared COVID-19 as a pandemic,and Tunisia implemented a containment and targeted screening *** country’s public health policy has since f.cused on managing hospital ***:The study analyz.d the bed occupancy rates in public hospitals in Tunisia during the *** evolution of.daily cases and nonpharmaceutical interventions(NPI)actions undertaken by the Tunisian Government were also *** study used 3 indices to assess bed f.exibility:Ramp duration until the peak,ramp growth until the peak,and ramp rate until the *** study also calculated the time shif. at the start and peak of.each wave to evaluate the government’s response ***:The study f.und that the evolution of.the epidemic in Tunisia had 2 *** f.rst phase saw the pandemic being controlled due to strong NPI actions,while the second phase saw a relaxation of.measures and an increase in wave *** bed availability f.llowed the demand f.r beds,but ICU bed occupancy remained high,with a maximum of.97%.The government’s response in terms of.bed distribution and reallocation was *** study f.und that the most deadly wave by ICU occupied bed was the third wave due to a historical variant,while the f.f.h wave due to the delta variant was the most deadly in terms of.cumulative ***:The study concluded that decision-makers could use its f.ndings to assess their response capabilities in the current pandemic and f.ture *** study highlighted the importance of.f.exible and responsive healthcare systems in managing pandemics.

关键词： Bed occupancy Daily cases Daily death Ramp duration until the peak(RDUP) Ramp growth until the peak(RGUP) Ramp rate until the peak(RRUP)