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Search Results: 1 - 10 of 416018 matches for " Mohamed M. El-Molla "
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Part 1: Synthesis and Evaluation of Novel Nano Scale Powdered Polyurethane Acrylate Binders  [PDF]
Mohamed M. El-Molla, Karima Haggag, Fatma N. El-Shall, N. O. Shaker
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.22026
Abstract: Some new an aqueous polyurethane acrylate (waterborne binder) based on polyethylene glycol with different M. wt. mixed with polyol were carried out. Seven different polyurethane acrylate co-polymers were prepared aiming at substituting the two hydroxyl groups of polyethylene glycol (6000, 12,000 and 20,000 g/mol) and two primary hydroxyl groups of polyol through their reaction with corresponding calculated amounts of either isophorone diisoyanate or toluene diisocyanate and caped the remaining isocyanate group with either hydroxy ethyl acrylate or hydroxy propyl methacrylate to get on the polyurethane acrylate polymers [PUA]. From DSC measurement the result of Tg of synthesized PUA are in range from -8.78℃ to 36.4℃. So they can classify as soft binders. The infrared spectra, rheological properties, viscosity measurement, the weight average molecular weight, of the synthesize binders were investigated.
Use of the Newly Synthesized Aqueous Polyurethane Acrylate Binders for Printing Cotton and Polyester Fabrics  [PDF]
Mohamed M. El-Molla, Hanan S. El-Sayad, Madiha A. El-Kashouti, Rasha S. El-Khawaga
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.22027
Abstract: The use of the four new synthesized polyurethane acrylate binders in the pigment print paste for screen printing cotton and polyester fabrics and pigment fixation through the polymerization process of the binder by using the thermofixation technique as well as the UV curing technique was studied. The effect of changing time and temperature of thermofixation, and the time of UV curing on the color strength, and prints fastness properties were also studied. The results showed that, the newly synthesized polyurethane acrylate binders could be successfully used for pigment fixation on cotton and polyester using the two fixation techniques and in general their prints possessed better color strength values as compared to those obtained upon using the selected commercial binders.
Synthesis of Novel Acid Dyes with Coumarin Moiety and Their Utilization for Dyeing Wool and Silk Fabrics  [PDF]
Mahmoud S. Bashandy, Fatma A. Mohamed, Mohamed M. El-Molla, Mahmoud B. Sheier, Ahmed H. Bedair
Open Journal of Medicinal Chemistry (OJMC) , 2016, DOI: 10.4236/ojmc.2016.61002
Abstract: This article describes the synthesis of some novel coumarin compounds to use as acid dyes by using compounds 1 - 4 as starting materials, which were prepared by interaction of 2-hydroxybenzaldehyde with ethyl 3-oxobutanoate, diethylmalonate, 4-nitrobenzenediazonium chloride and 4-sulfobenzenediazonium chloride, respectively. Compound 1 reacted with bromine and 2-cyanoacetohydrazide to give phenacyl bromide derivative 5 and 2-cyanoacetohydrazone derivative 6, respectively. Coupling of compound 6 with equimolar amount of 2-sulfo-4-((4-sulfophenyl) diazenyl)benzenediazonium chloride gave coumarin acid dye 8. Phenacyl bromide derivative 5 re-acted with potassium cyanide in refluxing ethanol to produce compound 7, which on coupling with equimolar amount of 8-hydroxy-6-sulfonaphthalene-2-diazonium chloride and 8-hydroxy-3,6-disulfonaphthalene-1-diazonium chloride gave coumarin acid dyes 9 and 10, respectively. Interaction of compound 2 with 2-amino-5-((4-sulfophenyl)diazenyl)benzenesulfonic acid, benzene-1,4-diamine and 3,3’-dimethoxy-[1,1’-biphenyl]-4,4’-diamine in refluxing ethanol afforded compounds 11, 12 and 14, respectively. Diazonium sulphate of compounds 12 and 14 coupling with 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid gave compounds 13 and 15, respectively. Cyclocondensation of compound 3 with ethyl 3-oxobutanoate, diethyl malonate and malononitrile afforded derivatives of 3-acetyl-2H-chromen-2-one 16, ethyl 2-oxo-2H-chromene-3-carboxylate 17 and 2-imino-2H-chromene-3-carbonitrile 18, respectively. Reaction of sodium benzenesulfonate derivative 4 with ethyl 3-oxobutanoate and hydrazine hydrate gave compounds 19 and 20, respectively. The structures of the newly synthesized compounds were confirmed by elemental analysis, UV/ VIS, IR, 1H NMR and Ms spectral data. The suitability of the prepared dyestuffs for dyeing of wool and silk fabrics has been investigated. The dyed fabric shows good light fastness, very good rubbing, perspiration, washing and excellent sublimation fastness. These dyes have been color shade from blue to violet with very good depth and levelness on fabrics. The dye bath exhaustion and fixation on fabric has been found to be very good.
Effects of y-Irradiation and Ageing on Surface and Catalytic Properties of Nano-sized CuO/MgO System
Sahar A. El-Molla,Sahar A. Ismail,Marwa M. Ibrahim
Revista de la Sociedad Química de México , 2011,
Abstract: El sistema de 0.2 Cu/MgO preparado por el método de impregnación fue calcinado a 350 y 450 oC. El efecto de la irradiación y (0.2-1.6 MGy) en su estructura, superficie y propiedades catalíticas, fue investigado utilizando XRD; la adsorción de N2 a -196 oC y la conversión catalítica de isopropanol a 150-275 oC fue determinada utilizando una técnica de flujo. Los resultados revelaron que los sólidos investigados consistieron de nano MgO como fase predominante, además de CuO y trazas de Cu2O. La radiación y de los sólidos investigados ejercen cambios medibles en su superficie y las propiedades catalíticas dependen de la temperatura de calcinación y de la dosis de radiación.El catalizador estudiado actúa como un sólido de deshidrogenación activo. Los 5 a os de envejecimiento de los diferentes sólidos mostraron cambios muy limitados en su superficie y en las propiedades catalíticas indicando una buena estabilidad catalítica de los sólidos preparados e irradiados.
过渡金属阳离子预处理对活性炭催化性能的提高
Sahar A. EL-MOLLA,Gamil A. EL-SHOBAKY,Sohair A. SAYED AHMED
催化学报 , 2007,
Abstract: ?首先将商用活性炭样品在1%的稀硝酸中处理,然后等体积浸渍在含有5%和10%(质量分数)硝酸钴、硝酸镍或硝酸铜的水溶液中,并在100℃干燥至恒重,最后将样品在Ar气氛中于400℃焙烧3h.采用X射线衍射、N2吸附和红外光谱等分析手段对不同固体样品进行了表征,并考察了其对异丙醇催化转化和25~45℃时过氧化氢催化分解的活性.结果表明,掺杂5%或10%的过渡金属氧化物后,活性炭样品中含有结晶度很差的CoO,Co3O4,NiO,Cu2O和CuO相的纳米晶.金属氧化物预处理使活性炭的BET比表面积略有增加.这些固体样品主要用作脱氢催化剂,其选择性均高于90%.在225℃时,经5%氧化钴、氧化镍和氧化铜处理的活性炭的催化活性比硝酸处理的活性炭分别提高了6%,24.6%和40.6%.少量CoO处理后的商用活性炭对H2O2催化分解活性的提高是由参与该催化反应的活性位浓度的显著增加而引起的,该处理过程并没有改变H2O2催化分解的机理.
Bioequivalence Study of Two Oral Doxycycline Formulations (Doxysol® and Doxymed®) in Healthy Broiler Chickens  [PDF]
Ahmed M. Soliman, Mohamed Aboubakr, Mohamed El-Hewaity
Pharmacology & Pharmacy (PP) , 2015, DOI: 10.4236/pp.2015.61001
Abstract: Aims: The present study was designed to assess the comparative bio-equivalence of Doxysol® and Doxymed® in healthy broiler chickens after oral administration of both products in a dose of 20 mg doxycycline/kg.b.wt. Materials and Methods: Twenty broiler chickens were divided into two groups. The first group was designed to study the pharmacokinetics of Doxysol, while the 2nd group was designed to study the pharmacokinetics of Doxymed. Each broiler chickens in both groups were injected intravenously with 20 mg doxycycline/kg.b.wt. Blood samples were obtained from the wing vein and collected immediately before and at 5, 15, 30 minute, 1, 2, 4, 6, 8, 12 and 24 hours after a single intravenous or oral administration. Results: Doxycycline in both products obeyed a two compartments open model following I.V. injection in a dose of 20 mg/kg.b.wt. The disposition kinetics of Doxysol® and Doxymed® following oral administration of 20 mg doxycycline base/kg.b.wt. revealed that the maximum blood concentration [Cmax.] were 4.70 and 4.65 μg/ml and attained at [tmax.] of 1.30 and 1.40 hours, respectively. Doxycycline in Doxysol® and Doxymed® was eliminated with half-lives [t0.5(β)] equal to 1.98 and 2.31 hours, respectively. The mean systemic bioavailability of doxycycline in Doxysol® and Doxymed® after oral administration in healthy chickens was 92.57 and 88.21%, respectively. Conclusion: Doxymed® is bioequivalent to Doxysol® since Cmax test/Cmax reference and AUCtest/AUCreference ratios were 99% and 90%, respectively.
Investigating Double-Regime Crossover in Y1Ba2Cu3 - xRxO7 - δ Superconductors  [PDF]
Mohamed H. Badr, Lubna M. Sharaf El-Deen, Mohamed El-Hofy, Aly A. Haswa
Crystal Structure Theory and Applications (CSTA) , 2014, DOI: 10.4236/csta.2014.31004
Abstract:

The effect of Pr and Gd doping on the transport properties of Cu-deficient YBCO superconductors has been studied. Two series of Y1Ba2Cu3 - xRxO7 - δ, where R = Pr or Gd, were prepared by the conventional solid-state reaction technique. Resistance measurements showed a suppression of Tc with increasing of Pr- and Gd-contents in addition to a normal-state metal-to-insulator transition. Moreover, a superconductor-to-insulator transition has been observed at ambient pressure for temperatures less than 50 K for Pr with x = 0.3 and for Gd with x > 0.3. The overall complex behaviours of the resistivity data have been preliminary explained in terms of localization of charge carriers, structural disorders, and magnetic ordering of magnetic moments.

A Modified Interactive Stability Algorithm for Solving Multi-Objective NLP Problems with Fuzzy Parameters in Its Objective Functions  [PDF]
Mohamed Abd El-Hady Kassem, Ahmad M. K. Tarabia, Noha Mohamed El-Badry
American Journal of Operations Research (AJOR) , 2016, DOI: 10.4236/ajor.2016.61002
Abstract:

This paper presents a modified method to solve multi-objective nonlinear programming problems with fuzzy parameters in its objective functions and these fuzzy parameters are characterized by fuzzy numbers. The modified method is based on normalized trade-off weights. The obtained stability set corresponding to α-Pareto optimal solution, using our method, is investigated. Moreover, an algorithm for obtaining any subset of the parametric space which has the same corresponding α-Pareto optimal solution is presented. Finally, a numerical example to illustrate our method is also given.

An Eco-Friendly Synthesis of Heterocyclic Moieties Condensed with Pyrazole System under Green Conditions and Their Biological Activity  [PDF]
Mohamed A. El-Borai, Hala F. Rizk, Mohamed R. Sadek, Mai M. El-Keiy
Green and Sustainable Chemistry (GSC) , 2016, DOI: 10.4236/gsc.2016.62008
Abstract: The efficient, facile and green synthesis of 4-bromo pyrazolone by using N-bromo saccharine as valuable green reagent encouraged us to prepare some new fused heterocycles as furopyrazole, pyranopyrazole, imidazopyrazole, pyrazolothiazole, pyrazol thiazolopyrimidine, pyrazolothiazine, oxathinopyrazole, pyrazolobenzooxazine, and pyrazoloquinoxaline. The synthesis was carried out by a basic condensation of bromo pyrazolone 2 and a suitable reagent in a one-pot reaction using chitosan as a green basic catalyst. The reactions were carried out by microwave irradiation technique as a green source of energy as well as the conventional heating. The antioxidant activity of the prepared compounds was studied using 1,1-phenyl-2-picrylhydrazyl (DPPH) assay and their antibacterial activity against Gram-positive, Gram-negative bacteria and antifungal activity was evaluated.
Implementation of HACCP Plan for the Production of Egyptian Kishk (A Traditional Fermented Cereal-Milk Mixture)  [PDF]
Mohamed M. Abd El-Razik, Mohamed F. Y. Hassan, Mohamed G. E. Gadallah
Food and Nutrition Sciences (FNS) , 2016, DOI: 10.4236/fns.2016.713116
Abstract: The aim of this study is implementation of Hazard Analysis and Critical Control Points (HACCP) system during production of Egyptian Kishk on small scale production. Kishk is a traditional dry fermented product consisted from salted sour butter milk (Laban zeer) or yoghurt with cracked and bran free parboiled wheat grains (Burghol); the mixture of cereal and milk allows fermenting at ambient temperature for different periods, then the fermented mixture is formed in ball form and dried. Kishk is consumed in Egypt and in most Arab countries. Since Kishk is prepared by traditional and consumed widely, safety of this product is very important in terms of consumer health. Therefore, HACCP system as food safety tool was adopted during preparation of Kishk. Hazard analysis of raw materials and during different production steps was established. A simple HACCP plan was implemented; critical control points of production were determined; critical limits, corrective actions and monitoring procedures for each critical control points were established; verification procedures were also discussed.
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