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On the friction and adhesion hysteresis between polymer brushes attached to curved surfaces: Rate and solvation effects

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Friction 2015年第2期3卷 148-160页

作者： Sissi de BEER G.DjuidjéKENmOÉ martin h.müser materials Science and Technology of Polymers MESA+Institute for NanotechnologyUniversity of TwenteP.O.Box 2177500 AE Enschedethe Netherlands Jülich Supercomputing Centre Institute for Advanced Simulation FZ Jülich 52425 JülichGermany Department of Physics Laboratory of Mechanics Faculty of ScienceUniversity of YaoundéP.O.Box 812YaoundéCameroon

Computer simulations of friction between polymer brushes are usually simplified compared to real systems in terms of solvents and *** most simulations,the solvent is only implicit with infinite compressibility and zero *** addition,the model geometries are parallel walls rather than curved or rough as in *** this work,we study the effects of these approximations and more generally the relevance of solvation on dissipation in polymer-brush systems by comparing simulations based on different solvation *** find that the rate dependence of the energy loss during the collision of brush-bearing asperities can be different for explicit and implicit ***,the non-Newtonian rate dependences differ noticeably between normal and transverse motion,i.e.,between head-on and off-center asperity ***,when the two opposing brushes are made immiscible,the friction is dramatically reduced compared to an undersaturated miscible polymer-brush system,irrespective of the sliding direction.

关键词： polymer brushes biomimetic materials molecular dynamics simulation

Application of shortened heat treatment cycles on A356 automotive brake calipers with respective globular and dendritic microstructures

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Transactions of Nonferrous metals Society of China 2010年第9期20卷 1780-1785页

作者： h.mLLER G.GOVEN DER W.E.STUmPF materials Science and manufacturing Council for Scientific and Industrial Research (CSIR) Department of materials Science and metallurgic al Engineering University of Pretoria

Since the automotive industry has many possible applications for semi-solid metal (SSm)-high-pressure die casting (hPDC) parts, the newly developed heat treatment cycles, as well as the traditional heat treatment cycles, were applied to A356 brake calipers cast using a LK DCC630 hPDC *** hardness measurements at a cross section of the brake calipers were performed, indicating that similar values can be obtained when using the significantly shorter heat treatment ***, the typical tensile properties that can be obtained for SSm-hPDC A356 brake calipers are compared with those manufactured by gravity die *** indicate that the differences in microstructures (globular or dendritic) do not have a noteworthy effect on the heat treatment *** implies that the short heat treatment cycles originally developed for globular SSm-hPDC A356 castings can be successfully applied to dendritic liquid A356 castings too.

关键词： semi-solid metal (SSm) forming heat treatment A356 brake caliper gravity die casting automotive

Characterization of surface liquid segregation in SSm-hPDC aluminium alloys 7075,2024,6082 and A201

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中国有色金属学会会刊：英文版 2010年第S3期20卷 847-851页

作者： h.mLLER U.A.CURLE E.P.mASUKU materials Science and manufacturing Council for Scientific and Industrial Research(CSIR)PretoriaSouth Africa

The surface liquid segregation(SLS) phenomenon in semi-solid metal-high pressure die casting(SSm-hPDC) plates of 7075,2024,6082 and A201 was investigated by different *** profiles were determined by firstly measuring the ch.mical composition of the surface of the plates using a Thermo Quantris optical emission spectrometer(OES).material was then removed by a grinding process followed by measurement of the amount of material removed and ch.mical *** profiles of the main alloying elements were plotted for the cross-section of the plates in the as-cast and T6(after solution treatment) temper *** hardness profiles from the surface to the centre of the plates were *** samples of cross-sections of the castings were prepared and evaluated using a scanning electron *** results show that surface liquid segregation in SSm-hPDC alloys causes significant differences in properties between the surface and the bulk of these castings in both the F and T6 temper conditions.

关键词： semi-solid metal(SSm) forming alloy 7075 alloy 2024 alloy 6082 alloy A201 surface liquid segregation

Nitriles in heterocyclic synthesis: studies on ethyl 3-amino-4,4-dicyano-3-butenoate

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Chinese Journal of Ch.mistry 1991年第5期9卷 461-466页

作者： SOLImAN A.Y BAKEER h.m Department of Ch.mistry Faculty of Education Fayoum Cairo University Egypt Department of Chemistry Faculty of Education Fayoum Cairo University Egypt

New polyfunctionally substituted heterocyclic compounds were synthesized from ethyl 3-amino-4, 4-dicyano-3-butenoate (1) as a starting material.

关键词： CI studies on ethyl 3-amino-4,4-dicyano-3-butenoate Nitriles in heterocyclic synthesis

Experimental approaches and analytical technique for determining heavy metals in fallen dust at ferrosilicon production factory in Edfu, Aswan,Egypt

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2005年第8期6卷 708-718页

作者： SOLTAN m.E RAGEh h.m RAGEh N.m AhmED m.E Department of Ch.mistry Faculty of Science at Aswan South Valley UniversityEgypt Department of Chemistry Faculty of Science at Qena South Valley UniversityEgyptDepartment of Chemistry Faculty of Science at Qena South Valley UniversityEgyptDepartment of Environment Egyptian Ferroalloy Edfu AswanEgypt

In this study aimed to evaluate the pollution extent of metals and nonmetals inside and outside the ferrosilicon production factory in Edfu, Aswan, Egypt, raw materials (quartz, cokes, iron oxides), ferrosilicon alloy, silica fume, dust and suspended dust (at different sites) samples were collected from the factory, and fallen dust samples were collected from outside the factory, horizontally (at different sites and different distance and directions) and vertically (at different floors in the selected buildings). Gravimetric methods, X-ray fluorescence (XRF), flame photometer, wide range carbon determinator and atomic absorption spectroscopy tools were used for elements determination. The results indicating that the fallen dust and its element contents on southern factory walls being higher than those on eastern factory walls may be due to the nature of the dusts and effects of wind force and wind direction. Fallen dust levels in different regions outside the factory were found to be affected by the distance, direction and floors. The nature of dust samples was affected by gravity and the suspended dust in different factory units depended on the work capacity and method of handling materials by personnel in different production units. Silica fume was a complicated problem, had dangerous effect against the workers' health, and was characterized by high concentrations of SiO2(90.6%～93.6%) and heavy metals (mn, 420.6×10-6～520.3×10-6; Fe, 2354×10-6～2685×10-6; Co, 80.7×10-6～101.6×10 6 and Ni,5.3× 10-6～6.05× 10-6). The TSP (Total Suspended Particulate) levels in all factory units were higher than the recommended air quality value (70 μg/m3) under Egyptian law. The effect of ferrosilicon factory fallen dust on the surrounding regions decreased with increasing distance between the factory and these regions. The suspended dust samples in the factory units and their components greatly exceeded national and international standards, so health and environmental criteria must be

关键词： Air pollution Dust heavy metals Fallen dust

Influence of surface liquid segregation on corrosion behavior of semi-solid metal high pressure die cast aluminium alloys

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中国有色金属学会会刊：英文版 2010年第S3期20卷 837-841页

作者： E.P.mASUKU h.mLLER U.A.CURLE P.C.PISTORIUS materials Science and manufacturing Council for Scientific Industrial ResearchPretoriaSouth Africa Department of materials Science and Engineering Carnegie Mellon UniversityPittsburghUSA

The corrosion behavior(in chloride medium) of the surface layer of SSm-hPDC plates of alloys 7075-T6 and 2024-T6 was compared with that of the wrought alloys 7075-T6 and *** testing was performed in deaerated 3.5%NaCl *** separate tests,the open-circuit potential was monitored in aerated 3.5% NaCl for 30 min after *** electroch.mical tests show that there is no significant difference in the pitting potential of the wrought alloys and that of the Cu-enriched surfaces of the SSm-hPDC alloys.

关键词： semi-solid metal(SSm) forming wrought aluminium alloys alloy 7075 alloy 2024 corrosion surface liquid segregation

Clinical,laboratory,and therapeutic differences between immunoglobulin E-mediated and non-immunoglobulin E-mediated cow’s milk protein allergy in children

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World Journal of Clinical Pediatrics 2025年第1期14卷 78-92页

作者： hasan m Isa marwa J Abdulnabi Nawra S Naser Fatema N Lahmda Noor m AlAnsari Zahra h Isa Afaf m moh.med Department of Pediatrics Salmaniya Medical ComplexManama 26671Bahrain Department of Pediatrics Arabian Gulf UniversityManama 26671Bahrain Faculty of medicine Mansoura UniversityMansoura 35516Egypt Public health Directorate Ministry of HealthManama 26671Bahrain

BACKGROUND Although breast milk is ideal for newborns,in some cases,it is replaced with cow’s milk,which contains proteins that increase the risk of cow’s milk protein allergy(CmPA).AIm To evaluate CmPA prevalence in Bahrain and compare clinical characteristics of children with immunoglobulin E(IgE)-and non-IgE-mediated *** This retrospective cohort study examined children with CmPA diagnosed at the pediatric gastroenterology outpatient clinic of the Salmaniya medical Complex,Bahrain,between 2014 and 2022,and assessed CmPA *** presentations,laboratory findings,dietary modifications,and outcomes were compared between children with IgE-mediated and non-IgE-mediated *** variables were compared using Fisher’s exact test or Pearson’sχ2 test,whereas continuous variables were compared using Student’s t-test or the mann-Whitney U *** Of 8332 patients,6022(72.3%)adhered to their *** th.m,618(10.3%)were suggested of having CmPA and 595(96.3%)were included;CmPA prevalence was 2%.most patients were Bahraini(93.8%)and males(55.3%).Non-IgE-mediated type accounted for 77.3%cases and IgE-mediated type,22.7%.IgE-mediated CmPA presented more in boys(P=0.030),and later in life(5.1 months±4.5 months vs 4.2 months±4.2 months,P=0.016,95%CI:0.08-1.73),had more associated diseases(Ph.more cutaneous(P=0.024)and respiratory(P=0.003)manifestations,severe symptoms[rash/dry skin(P=0.031),facial swelling/angioedema(P=0.003),failure to thrive(P=0.013),apparent life-threatening event(Physical findings(P=0.002)than non-IgE-mediated *** patients were exclusively fed cow milk formula(50.3%).The amino acid-based formula(AAF)was most prescribed(60.5%)with no difference between the two types(P=0.173).Although breastfeeding was recommended to 49.6%,only 8.2%were exclusively ***-mediated CmPA was associated with a longer follow-up duration than non-IgE-mediated CmPA(17.3 months±14.0 mo

关键词： Children milk allergy Immunoglobulin E Breastfeeding Infant formula Bahrain

Effect of Ni^(+2)-substituted Fe_2TiO_5 on the h_2-reduction and CO_2 Catalytic Decomposition Reactions at 500℃

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Journal of materials Science & Technology 2006年第6期22卷 846-850页

作者： m.h.Khedr Ch.mistry Department Faculty of ScienceBenisuef UniversityEgypt

CO2 is a major component of the greenhouse gases, which causes the global warming. To reduce CO2 gas, high activity nanosized Ni＋2 substituted Fe2TiO5 samples were synthesized by conventional ceramic method. The effect of the composition of the synthesized ferrite on the h2-reduction and CO2-catalytic decomposition was investigated. Fe2TiO5 （iron titanate） phase that has a nanocrystallite size of -80 nm is formed as a result of heating Fe2O3 and TiO2 while the addition of NiO leads to the formation of new phases （-80 nm） NiTiO3 and NiFe2O4, but the mixed solid of NiO and Fe2O3 results in the formation of NiFe2O4 only. Samples with Ni^＋2=0 shows the lowest reduction extent （20%）; as the extent of Ni＋2 increases, the extent of reduction increases. The increase in the reduction percent is attributed to the presence of NiTiO3 and NiFe2O4 phases, which are more reducible phases than Fe2TiO5. The CO2 decomposition reactions were monitored by thermogravimetric analysis （TGA） experiments. The oxidation of the h2-reduced Ni＋2 substituted Fe2TiO5 at 500℃ was investigated. As Ni^＋2 increases, the rate of reoxidation increases. Samples with the highest reduction extents gave the highest reoxidation extent, which is attributed to the highly porous nature and deficiency in oxygen due to the presence of metallic Fe, Ni and/or FeNi alloy. X-ray diffraction （XRD） and transmission electron microscopy （TEm） of oxidized samples show also the presence of carbon in the sample containing Ni＋2〉0, which appears in the form of nanotubes （25 nm）.

关键词： Nanocrystallite Ferrite Titanate Reduction CO2 decomposition Carbon nanotubes

Comparative analysis of different static mixers performance by CFD technique:An innovative mixer

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Chinese Journal of Ch.mical Engineering 2020年第3期28卷 672-684页

作者： m.m.haddadi S.h.hosseini D.Rashtchian martin Olazar Ch.mical and Petroleum Engineering Department Sharif University of TechnologyTehranIran Department of Ch.mical Engineering.Ilam University llam 69315-516Iran Department of Ch.mical Engineering University of the Basque Country(UPV/EHU)Sarriena s/nLeioaSpain

The flow and mixing behavior of two miscible liquids has been studied in an innovative static mixer by using CFD,with Reynolds numbers ranging from 20 to *** performance of the new mixer is compared with those of Kenics,SmX,and Komax static *** pressure drop ratio(Z-factor),coefficient of variation(CoV),and extensional efficiency(α)features have been used to evaluate power consumption,distributive mixing,and dispersive mixing performances,respectively,in all *** model is firstly validated based on experimental data measured for the pressure drop ratio and the coefficient of *** results are consistent with.measured data and those obtained by available correlations in the *** new mixer shows a superior mixing performance compared to the other mixers.

关键词： CFD New static mixer Coefficient of variation Pressure drop ratio