检索结果-南通市图书馆

Synthesis,antimicrobial, antiquorum-sensing and cytotoxic activities of new series of benzothiazole derivatives

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2015年第12期26卷 1522-1528页

作者： moustafa T.Gabr Nadia S.el-Gohary Eman R.el-Bendary mohamed m.el-kerdawy Nanting Ni mona I.Shaaban Department of medicinal Chemistry Faculty of Pharmacy Mansoura University Department of Chemistry Georgia State University Department of microbiology Faculty of Pharmacy Mansoura University Department of microbiology College of Pharmacy Taibah University

New series of benzothiazole derivatives were designed and synthesized. The newly synthesized compounds were screened for their antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus cereus. Compounds 6j and 6o showed the highest activity against E. coli and S. aureus. The antifungal activity of these compounds was also tested against Candida albicans and Aspergillus fumigatus293. Compounds 4c, 4g and 6j exhibited the highest activity against C. albicans. In addition, compounds4 a and 6j displayed promising activity against A. fumigatus 293. The same compounds were examined for their antiquorum-sensing activity against Chromobacterium violaceum ATCC 12472, whereas compounds4 a, 6j and 6p showed moderate activity. The in vitro cytotoxicity testing of the synthesized compounds was performed against cervical cancer（Hela） and kidney fibroblast cancer（COS-7） cell lines. Results indicated that all tested compounds have IC50 values 〉50 mmol/L against both cell lines. molecular properties, toxicities, drug-likeness, and drug score profiles of compounds 4a–c, 5a, 6g,h, 6j, 6l, 6o and7 c,d were also assessed.

关键词： antibacterial moiety antifungal antimicrobial cytotoxic screened moderate substituent Candida albicans

Processing of Ceramic Based Nanocomposite Usingα-Al_2O_3 Powder and FeCl_2 Solution as Starting materials

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2007年第6期23卷 837-842页

作者： mohamed m.el-Sayed Seleman Department of materials and metallurgical Engineering Faculty of Petroleum and Mining EngineeringPost Code 43721SuezEgypt

Alumina-iron nanocomposite powders were prepared by a two-step process. In the first step, α-Al2O3-FeCl2 powder mixture was formed by mixing α-Al2O3 powders with FeCl2 solution followed by drying. In the second step, the FeCl2 in the dry power mixture was selectively reduced to iron particles. A reduction temperature of 750℃ for 15 min in dry H2 was chosen based on the thermodynamic calculations. The concentration of iron in FeCl2 solution was calculated to be 20 vol. pct in the final composite. Two techniques were used to produce composite bulk materials. The Al2O3 nanocomposite powders were divided to two batches. The first batch of the produced mixture was hot pressed at 1400℃ and 27 mPa for 30 min in a graphite die. To study the effect of oxygen on the Al2O3/Fe interface bonding and mechanical properties of the composite, the second batch was heat treated in air at 700℃ for 20 min to partially oxidize the iron particles before hot pressing. Characterization of the composites was undertaken by conventional density measurements, X-ray diffractometry （XRD）, scanning electron microscopy （SEm）, transmission electron microscopy （TEm） and electron probe micro analysis （EPmA）. The suggested processing route （mixing, reduction and hot pressing） produces ceramic-metal nanocomposite much tougher than the pure Al2O3. The fracture strength of the produced Al2O3/Fe nanocomposite is nearly twice that of the pure Al2O3. The presence of spinel phase, FeAl204, as thick layer around the Fe particles in the Al2O3 matrix has a detrimental effect on interfacial bonding between Fe and AI203 and the fracture properties of the composite.

关键词： Ferrous chloride Reduction Alumina-iron nanocomposite Spinel phase

Advantages and disadvantages of nuclear reactions used in reactors or cyclotrons,in addition to a theoretical study based on photodisintegration on natural indium for^(111)Ag production

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2022年第2期33卷 1-13页

作者： Khaled m.el-Azony Nader m.A.mohamed Dalal A.Aloraini Radioactive Isotopes and Generators Department Hot Labs.CenterEgyptian Atomic Energy AuthorityP.O.Box 13759CairoEgypt Reactors Department Egyptian Atomic Energy AuthorityP.O.Box 13759CairoEgypt Physics Department College of SciencePrincess Nourah Bint Abdulrahman UniversityRiyadhKingdom of Saudi Arabia

Production routes were recorded on available reactions for^(111)Ag production from nuclear reactors or cyclotrons using a natural palladium target based on^(110)Pd(n,γ)and^(110)pd(d,n)reactions,respectively.^(nat)Cd(γ,x)based on^(110)Cd(γ,p)has also been studied as a prospective reaction for the production of^(111)***,these nuclear reactions are difficult to utilize because,in some cases,they reduce the specific activity of^(111)*** is a consequence of the stable silver isotopes produced in high *** isotopes include^(107,109)Ag and,in other cases,the high impurity of silver radioisotopes,such as^(110)m,^(106)m,^(105)Ag,that are produced during parallel nuclear *** to a scarcity of data regarding the(γ,α)reaction,the gamma reaction on natural indium for^(111)Ag production based on the^(115)In(γ,α)reaction was *** ^(nat)In(γ,α)reaction satisfies the criteria as a possible reaction to produce^(111)Ag with a sufficient yield and purity as consequence of the high^(115)In(95.7%)abundance as an enriched form and a relatively soft background caused by the parallel nuclear reactions.

关键词： Silver-111 Nuclear data Natural cadmium Natural palladium Natural indium

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

在线全文

学校读者我要写书评

暂无评论

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 Scientific 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 fabricate 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 successfully been fabricated by powder metallurgy process. At first, the mixed aluminum and graphite powders were cold compacted at 200 mPa and then sintered at 500 ℃ for 1 h followed by hot extrusion at 450 ℃. The influence of ceramic phases（free graphite and in-situ formed carbides） on microstructure, physical and mechanical properties of the produced composites were finally investigated. The results show that the fabricated 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% for all hot extruded *** strength, reduction in height, ultimate tensile stress, fracture stress, yield stress, and fracture 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 focusing on the in-situ formed ceramic phases, silicon carbide（SiC） and aluminum carbide（Al4 C3）. The ductile fracture mode of the produced composites became less dominant with increasing free graphite content and in-situ formed 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 Fracture behavior

Strength and Wear Behavior of mg Alloy AE42 Reinforced with Carbon Short Fibers

在线全文

学校读者我要写书评

暂无评论

Acta metallurgica Sinica(English Letters) 2019年第1期32卷 31-40页

作者： Sabbah Ataya Naser A.Alsaleh mohamed m.el-Sayed Seleman metallurgical and materials Engineering Department Faculty of Petroleum and Mining Engineering Suez University Department of mechanical Engineering College of Engineering Al Imam Mohammad Ibn Saud University

In addition to the advantage of the lightweight of magnesium alloys, magnesium composites have moderate strength and elastic modulus. The proposed application of magnesium composites as diesel truck pistons makes it necessary to assess their wear performance. Little research data have been discussed on wear behavior of mg alloy AE42 matrix and its composites. Thus, this paper reports wear behavior of magnesium alloy AE42(mg–Al–mn—RE; rare earth) and its composite AE42-C, which contains 23 vol% of randomly oriented carbon short fibers. materials characterization, including density measurements, hardness testing, microstructures investigation, and compression testing at temperatures of 25, 150,and 300 °C, were conducted. Wear tests were performed under various loads and sliding distances. Wear mechanisms were also proposed based on the examination of worn surfaces using optical microscopy and scanning electron microscopy equipped with EDX(energy-dispersive X-ray spectrometry) analysis system. The hardness of AE42-23 vol% C composite is twice the hardness of the mg matrix alloy AE42. Significant improvements to yield stress and compressive strength at temperatures of 25, 150, and 300 °C of the composite versus the AE42 alloy are achieved. Wear resistance of the composite is improved considerably versus that of the mg alloy AE42 at the various sliding distances. Smearing of graphite on the worn surface produces a lubricating film that delays change from mild to severe wear of the composite, especially at high loads. EDX analysis of the worn surface shows oxidation of the matrix alloy at higher wear loads, and this mechanism decreases in the presence of carbon fibers under the same loads. Abrasive wear, oxidation, and plastic deformation are the dominant wear mechanisms for the alloy matrix AE42, whereas mainly abrasive wear is the wear mechanism of AE42-23 vol% C composite under the proposed testing conditions.

关键词： magnesium composites Carbon short fibers Compressive strength Wear resistance Wear mechanisms

macrobenthos monitoring in the Gulf of Suez,Egypt

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2008年第2期27卷 55-80页

作者： mohamed m.el-Komi National Institute of Oceanography and Fisheries

The biogeography of macrobenthic communities with large-scale differences in species distribution and abundance was studied along the eastern and western coastal regions of the Gulf of Suez to indicate biodiversity of benthos in relation to the prevailing environmental conditions. In general, benthos have a wide variety of species of mainly polychaet worms, crustaceans, bivalves, and other bottom invertebrates living in burrows in/or on the sediment surface. Coastal development clearly affects the ecosystem after the construction of coastal projects. The highest values of benthic diversity, evenness, richness and dominance are found at the Gulf of Suez （WG 1, WG 3）, Ras Gharib （WG 7, WG 8） and Ras Shukier （WG 9a） by contrast to others. The abundance of macrobenthic organsims along the coasts of Gulf of Suez can be arranged in the following sequence： other groups （34%） greater than crustaceans （25%） greater than polychaetes （22%） greater than molluscs （17%） greater than echinoderms （2%）. The biomass of benthic assemblages at different sampling sites can also be ranked as follows： echinoderms （52%） greater than molluscs （27%） greater than crustaceans （16%） greater than polychaetes （2%） greater than other groups （3%）. Some benthic groups or species indicated a distinctive correlation to pollution sources in the marine ecosystem which obviously increased in the coastal areas due to the extension of the coastal development. These activities needed regular information to establish database for the biology and distribution of marine benthic communities. The density and diversity of benthos are significantly affected by eutrophication at Ain Sukhna, whereas the benthos in the open Gulf of Suez do not seem to be adversely affected by pollution.

关键词： macrobenthos assessment impact Gulf of Suez

Review on friction stir welding of dissimilar magnesium and aluminum alloys: Scientometric analysis and strategies for achieving high-quality joints

在线全文

学校读者我要写书评

暂无评论

Journal of magnesium and Alloys 2023年第11期11卷 4082-4127页

作者： mohamed m.Z.Ahmed mohamed m.el-Sayed Seleman Dariusz Fydrych Gürel ÇAm Department of mechanical Engineering College of Engineering at Al KharjPrince Sattam Bin Abdulaziz UniversityAl Kharj 11942Saudi Arabia Department of metallurgical and materials Engineering Faculty of Petroleum and Mining EngineeringSuez UniversitySuez 43512Egypt Faculty of mechanical Engineering and Ship Technology Institute of Machines and Materials TechnologyGdańsk University of TechnologyGabriela Narutowicza Street 11/12Gdańsk 80-233Poland Department of mechanical Engineering Iskenderun Technical UniversityIskenderunHatay 31200Turkiye

magnesium and aluminum alloys continually attract interest as lightweight structural materials for transport applications. However, joining these dissimilar alloys is very challenging. The main obstacle that hinders progress in dissimilar mg-Al joining is the formation of brittle intermetallic compounds(ImCs). As a solid-state joining technique, FSW is an excellent candidate to attenuate the deleterious ImC effects in dissimilar Al-mg joining due to the inherent low heat inputs involved in the process. However, the ImCs, namely Al_(3)mg_(2) and Al_(12)mg_(17) phases, have also been reported to form during Al-mg dissimilar FSW;their amount and thickness depend on the heat input involved;thus,the weld parameters used. Since the heat dissipated in the material during the welding process significantly affects the amount of ImCs,the heat input during FSW should be kept as low as possible to control and reduce the amount of ImCs. This review aims to critically discuss and evaluate the studies conducted in the dissimilar Al/mg FSW through a scientometric analysis and also with a focus on the strategies recently applied to enhance joint quality. The scientometric analysis showed that the main research directions in mg/Al FSW are the technological weldability of aluminum and magnesium during FSW, structural morphology, and mechanical properties of dissimilar welded joints. Considering the scope of application of the aforementioned joints, the low share of articles dealing with environmental degradation and operational cracking is surprising. This might be attributed to the need for well-developed strategies for obtaining high-quality and sustainable joints for applications. Thus, the second part of this review is conventional, focusing mainly on the new strategies for obtaining high-quality mg/Al joints. It can be concluded that in addition to the necessity to optimum welding parameters to suppress the excessive heat to limit the amount and thickness of ImC formed and improv

关键词： Friction stir welding(FSW) Al-alloys mg-alloys Dissimilar material welding Intermetallics Weld performance

SUBORDINATION PROPERTIES OF mULTIVALENT FUNCTIONS INVOLVING AN EXTENDED FRACTIONAL DIFFERINTEGRAL OPERATOR

在线全文

学校读者我要写书评

暂无评论

Acta mathematica Scientia 2014年第2期34卷 367-379页

作者： mohamed K.AOUF Teodor BULBOACA Rabha m.el-ASHWASH Department of mathematics Faculty of ScienceMansoura University Faculty of mathematics and Computer Science Babes-Bolyai University

The object of this article is to investigate inclusion, radius, and other various properties of subclasses of multivalent analytic functions, which are defined by using an extended version of the Owa-Srivastava fracti... 详细信息

关键词： Analytic functions p-valent functions meromorphic functions differintegraloperator differential subordination

Development of a Smart Technique for mobile Web Services Discovery

在线全文

学校读者我要写书评

暂无评论

Computers, materials & Continua 2021年第11期69卷 1483-1501页

作者： mohamed Eb-Saad Yunyoung Nam Hazem m.el-bakry Samir Abdelrazek Department of Information Systems Faculty of Computers and InformationMansoura UniversityMansoura35516Egypt Department of Computer Science and Engineering Soonchunhyang UniversityAsan31538Korea

Web service(WS)presents a good solution to the interoperability of different types of systems that aims to reduce the overhead of high processing in a resource-limited *** the increasing demand for mobile WS(mWS),the WS discovery process has become a significant challenging point in the WS lifecycle that aims to identify the relevant mWSs that best match the service *** discovery process is a resource-consuming task that cannot be performed efficiently in a mobile computing environment due to the limitations of mobile ***,a cloud computing can provide rich computing resources for mobile environments given its unlimited and easily scalable *** paper proposes a semantic WS discovery and invocation framework in mobile environments based on cloud and a relationship-aware matchmaking *** discovery algorithm enriches mWS and user requests semantically with the functional and non-functional properties of Ontology Web Language for Services,such as Quality of Web Service,device context,and user *** WS repository is filtered based on logical reasoning and a parameter-based matching algorithm to minimize the matching space and improve runtime *** cosine similarity between the user request and services repository is then assessed to generate the most relevant *** relationships among concepts in the ontology are considered to improve the recall and precision *** the WS discovery process,users can invoke and test these services in a mobile environment through a dynamic user *** interface of the invocation process is changed according to the WS description *** application prototype is also developed to evaluate the framework based on a Cordova cross-mobile development framework.

关键词： Cloud web service web service discovery semantic matching mobile web service discovery