检索结果-南通市图书馆

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

C3-Modules

Algebra Colloquium 2015年第4期22卷 655-670页

作者： Ismail Amin Yasser ibrahim Mohamed Yousif Department of Mathematics Faculty of Science Cairo University Giza Egypt Department of Mathematics The Ohio State University Lima Ohio 45804 USA

One of the continuity conditions identified by Utumi on self-injective rings is the C3-condition, where a module M is called a C3-module if whenever A and B are direct summands of M and A A B = 0, then A B is a summand of M. In addition to injective and direct-injective modules, the class of C3-modules includes the semisimple, continuous, indecomposable and regular modules. Indeed, every commutative ring is a C3-ring. In this paper we provide a general and unified treatment of the above mentioned classes of modules in terms of the C3-condition, and establish new characterizations of several well known classes of rings.

关键词： injective and quasi-injective modules C2-modules and C3-modules

Orientation on the Mechanistics of Electron-Transfer on Oxidation of Chondroitin-4-Sulfate as Sustainable Sulfated Polysaccharide by Permanganate Ion in Aqueous Perchlorate Solutions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2020年第2期8卷 205-218页

作者： Refat Hassan Hideo Takagi Samia ibrahim Department of Chemistry Faculty of ScienceAssiut UniversityAssiut71516Egypt Department of Chemistry School of ScienceResearch Center of Materials ScienceNagoya464-01Japan Department of Chemistry Faculty of ScienceNew Valley UniversityEl-Kharga72511New ValleyEgypt

A spectrophotometric investigation of oxidation of chondroitin-4-sulfate(CS)as a sustainable and biodegradable sulfated macromolecule by oxyanion permanganate ion as multi-equivalent oxidant in acid perchlorate solutions at a constant ionic strength of 2.0 mol dm^(-3)has been *** experimental results on the influence of the concentration of the reactants the reaction rates revealed first-order dependence in MnO^(-)_(4),fractional second-order in[CS]and fractional first-order with respect to the hydrogen ion *** hydrogen acid concentration dependence of the rate constants indicated that the oxidation rates were increased with increasing the acid concentration which means that the oxidation reaction is of acid-catalyzed *** oxidation of all other polysaccharides by this oxidant in acidic solutions indicated that the oxidation processes were proceeding throughout two distinct *** first stage was relatively slow,followed by a more fast reaction in the second *** addition of Mn^(2+)and F^(-)ions to the reaction mixtures indicated that the Mn^(3+)and/or Mn^(4+)as the reduced forms of permanganate were the reactive species in the second fast ***,neither formation of Mn^(3+)and/or Mn^(4+)transient species nor presence of two stages in the oxidation reaction were detected in the oxidation process,and this result was found to be on contrary to that observed for oxidation of all other polysaccharides by this *** of 1:2 coordination biopolymer intermediate complexes prior to the rate-determining step was revealed,*** of the oxidation product revealed the formation of keto-acid as derivative precursor of CS *** product was identified by formation of 2,4-dinitrophenyhydrazone and dioxime as wells as by the bands at frequencies 3430(OH of COOH group);1760-1730 cm^(-1)(broad)for C=O of diketone;1639 cm^(-1)ofν_(as),OCO;1418 cm^(-1)ofν_(s)OCO and 1338 cm^(-1)of C-O-C,respectively,in the

关键词： Chondroitin-4-sulfate permanganate oxidation electron-transfer kinetics mechanisms

Finding an optimization of the plate element of Egyptian research reactor using genetic algorithm

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2008年第5期19卷 314-320页

作者： WAHED Mohamed ibrahim Wesam EFFAT Ahmed Mathematics Department Faculty of ScienceZagazic UniversityEgypt Atomic Energy Authority CairoEgypt

The second Egyptian research reactor ET-RR-2 went critical on the 27th of November *** National Center of Nuclear Safety and Radiation Control (NCNSRC) has the responsibility of the evaluation and assessment of the safety of this *** purpose of this paper is to present an approach to optimization of the fuel element plate. For an efficient search through the solution space we use a multi objective genetic algorithm which allows us to identify a set of Pareto optimal solutions providing the decision maker with the complete spectrum of optimal solutions with respect to the various *** aim of this paper is to propose a new approach for optimizing the fuel element plate in the *** fuel element plate is designed with a view to improve reliability and lifetime and it is one of the most important elements during the shut *** this present paper,we present a conceptual design approach for fuel element plate,in conjunction with a genetic algorithm to obtain a fuel plate that maximizes a fitness value to optimize the safety design of the fuel plate.

关键词：埃及核反应堆遗传算法燃料元件核技术

Synthesis and characterization of poppy seed oil methyl esters

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2016年第8期24卷 1087-1096页

作者： Umer Rashid Muhammad ibrahim Imededdine Arbi Nehdi Saud ibrahim Al-Resayes Sammi Ullah Muhammad Aamer Mehmood Saira Shahzadi Institute of Advanced Technology Universiti Putra Malaysia Chemistry Department College of Science King Saud University Department of Environmental Sciences & Engineering Faculty of Engineering Government College University Faisalabad Department of Chemistry Government College University Faisalabad Department of Bioinformatics & Biotechnology Government College University Faisalabad Department of Chemistry Quaid-i-Azam University

Response surface methodology(RSM) was used to determine the optimum conditions of the methanolysis of crude poppy seed oil using Na OCH3 as catalyst. The experiments were run according to five levels, four variable central composite rotatable design(CCRD) using RSM. The reaction variables, i.e., molar ratio of methanol/oil(3:1–9:1), catalyst concentration(0.5 wt%–1.25 wt% Na OCH3), reaction temperature(25–65 °C), and reaction time(20–90 min) were studied. We demonstrated that the molar ratio of methanol/oil, catalyst concentration,and reaction temperature were the significant parameters affecting the yield of poppy seed oil methyl esters(PSOMEs). The optimum transesterification reaction conditions, established using the RSM, which offered a89.35% PSOME yield, were found to be 7.5:1 molar ratio of methanol/oil, 0.75% catalyst concentration, 45 °C reaction temperature, and 90 min reaction time. The proposed process provided an average biodiesel yield of more than 85%. A linear correlation was constructed between the observed and predicted values of the *** gas chromatography(GC) analyses have shown that PSOMEs contain linoleic-, oleic-, palmitic-, and stearic-acids as main fatty acids. The FTIR spectrum of the PSOMEs was also analyzed to confirm the completion of the transesterification reaction. The fuel properties of the PSOMEs were discussed in light of biodiesel standards(ASTM D 6751 and EN 14214).

关键词： Poppy oil Optimization Gas chromatography FTIR Fuel properties

Structural, M?ssbauer spectroscopy, magnetic properties, and thermal measurements of Y(3-x)Dy_x Fe_5O_(12)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第10期27卷 558-564页

作者： Mahdi Lataifeh Qassem I Mohaidat Sami H Mahmood ibrahim Bsoul Mufeed Awawdeh ibrahim Abu-Aljarayesh Mu'ath Altheeba Physics Department Yarmouk University Irbid 21163 Jordan Physics Department The University of Jordan Amman 11942 Jordan Physics Department AI al-Bayt University Mafraq 13040 Jordan

Yttrium iron garnet powder samples（Y3-xDyxFe5O12）, where part of yttrium ions are substituted by dysprosium ions with different concentrations are prepared by the solid state reaction method. The properties of the prepared samples are examined by different methods such as x-ray diffraction（XRD）, Mssbauer spectroscopy, macroscopic magnetization measurements, and thermal measurements. The XRD measurements show that all the samples reveal the presence of a single garnet phase with a BCC structure. Room temperature Mssbauer spectra indicate that iron ions occupy three magnetic sites, i.e., two octahedral sites and one tetrahedral site. The saturation magnetization and the initial magnetic susceptibility decrease with the increase of Dy^3＋ substitution. The Curie temperature obtained from the thermal measurements seems to be independent of Dy^3＋ substitution.

关键词： Mossbauer spectroscopy magnetic properties x-ray diffraction differential scanning calorimetry

ELECTRORHEOLOGY AND CREEP-RECOVERY BEHAVIOR OF CONDUCTING POLYTHIOPHENE/POLY(OXYMETHYLENE)-BLEND SUSPENSIONS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2012年第1期30卷 16-25页

作者： Ozlem Erol H.ibrahim Unal Bekir Sari Smart Materials Research Lab Chemistry Department Gazi UniversityAnkaraTurkey

Electrorheological properties and creep-recovery behavior of polythiophene/polyoxymethylene-blend having PT（50%）/POM（50%） composition were *** size,conductivity and dielectric values were measured to be 24.77μm,3.85×10^（-5） S·m^（-1） and 26.75,*** ratio was measured to be 64%at the end of 16 *** effects of dispersed particle volume fraction,external electric field strength,shear rate,frequency and temperature on ER properties and storage modulus of PT/POM-blend/silicone oil（SO） suspensions were *** were observed in the electric field viscosities of the suspensions and thus they were classified as a smart *** thinning non-Newtonian viscoelastic behavior was determined for PT/POM-blend/SO ***,time-dependent deformation was examined by creep-recovery tests and recoverable viscoelastic deformation established.

关键词： Conducting polythiophene/poly(oxymethylene) Blends Electrorheogical fluids Creep-recovery behavior

The efficiency of direct integration methods in elastic contact-impact problems

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2005年第4期21卷 395-401页

作者： ibrahim H.Guzelbey Ahmet Erklig Bahattin Kanber University of Gaziantep Mechanical Engineering DepartmentGaziantep-Turkey

A comparison of direct integration methods is madeand their efficiency is investigated for impact ***-mark,Wilson-θ,Central Difference and Houbolt Methodsare used as direct integration *** analysisincludes that of elastic and large deformation based uponupdated Lagrangian including buckling *** resultsshow that the direct integration methods give differentresults in different contact-impact cases.

关键词： Elastic impact,Direct integration methods,Finite strain Contact

Improved Integrity Constraints Checking in Distributed Databases by Exploiting Local Checking

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2009年第4期24卷 665-674页

作者： Ali A.Alwan Hamidah ibrahim Nur Izura Udzir Department of Computer Science Faculty of Computer Science and Information TechnologyUniversiti Putra Malaysia 43400 SerdangMalaysia

Most of the previous studies concerning checking the integrity constraints in distributed database derive simplified forms of the initial integrity constraints with the sufficiency property, since the sufficient test is known to be cheaper than the complete test and its initial integrity constraint as it involves less data to be transferred across the network and can always be evaluated at the target site （single site）. Their studies are limited as they depend strictly on the assumption that an update operation will be executed at a site where the relation specified in the update operation is located, which is not always true. Hence, the sufficient test, which is proven to be local test by previous study, is no longer appropriate. This paper proposes an approach to checking integrity constraints in a distributed database by utilizing as much as possible the local information stored at the target site. The proposed approach derives support tests as an alternative to the existing complete and sufficient tests proposed by previous researchers with the intention to increase the number of local checking regardless the location of the submitted update operation. Several analyses have been performed to evaluate the proposed approach, and the results show that support tests can benefit the distributed database, where local constraint checking can be achieved.

关键词： distributed database integrity constraint checking integrity constraint integrity test

Representation of the spatial association between salinity and water chemical properties in Al-Hassa Oasis

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2020年第2期13卷 168-174页

作者： ibrahim Alhawas Abdalhaleem A.Hassaballa Department of Environment&Agricultural Natural Resources College of Agricultural and Food SciencesKing Faisal UniversityKSA

With poor irrigation water quality,cultivation difficulties are certainly expected to *** will cause a severe reduction in crops yield unless a strong strategy is followed to control and sustain high yielding capacity under particular *** salinity presented in the form of water electrical conductivity(EC),has been presented in this study as one of the parameters that significantly participated in decreasing the quality of irrigation water in Al-Hassa oasis at Kingdom of Saudi *** sharing factors in quantifying water EC and its distribution spacewise has been examined by applying the frequency ratio(FR)technique(spatial autocorrelation)between salinity status and water measured elements,specifically,chlorine(Cl^(-)),sodium(Na^(+)),calcium(Ca^(2+)),potassium(K^(+))and magnesium(Mg^(2+)).A threshold salinity value of(EC≥2.0 dS/m)was identified as a break-line for classifying the well-water sources that non-valid for irrigating vegetables grown in the area.A statistical correlation among the examined parameters and EC was conducted using the statistical package for social sciences(SPSS),and compared to the applied FR technique.A dosage of Cl^(-) in irrigation water was observed to be the most significant candidate that raised EC,proved by an R^(2) of 63%.However,the FR technique has shown the validity in analyzing the spatial distribution of water measured variables;in addition to nominating the variable that had the higher association portion,which was assessed to be Na^(+),followed by Cl^(-) with prediction rates of 4.22 and 3.22,respectively.

关键词： statistical correlation GIS water salinity Al-Hassa prediction rate