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Corrosion Behaviour and Chloride Attack of Reinforcing Steel in Presence of Concrete Admixtures

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Journal of Materials Science & technology 1998年第4期14卷 339-343页

作者： I.Z.selim (Physical Chemistry Dept., National Research Center, Dokki, Cairo, Egypt Physical Chemistry Dept. National Research Center Dokki Cairo Egypt

Corrosion and electrochemical behaviour of reinforcing steel embedded in cement pastes with and without concrete admixtures used in Egypt to modify concrete properties have been studied. the influence of the admixtures on the corrosion resistance of the steel against chloride attack has been studied by using impressed current and impressed voltage techniques. the results indicate that the type and concentration of the used admixture have an important effect on the extent of chloride induced corrosion of the steel. the mechanism of corrosion of steel due to chloride attack was discussed. (Edited author abstract) 16 Refs.

关键词： SCE Corrosion Behaviour and Chloride Attack of Reinforcing Steel in Presence of Concrete Admixtures Res

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Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-tALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHAtIR t.CUONG-LE School of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for Engineering Application and technology Solutions Ho Chi Minh City Open University

this paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. the strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. the curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. the accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词： Kinetic energy

Determination of penetration depth at high velocity impact using finite element method and artificial neural network tools

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Defence technology（防务技术） 2015年第2期11卷 110-122页

作者： Nam?k KILI? Blent EKICI selim HARtOMACIOG LU Computer Aided Engineering Department Otokar Otomotiv ve Savunma San.A.SAtaturk Cad No: 9 Arifiye54580SakaryaTurkey Department of Mechanical Engineering Faculty of EngineeringMarmara University Department of Mechanical Engineering Faculty of Mechanical EducationMarmara University

Determination of ballistic performance of an armor solution is a complicated task and evolved significantly with the application of finite element methods(FEM) in this research *** traditional armor design studies performed with FEM requires sophisticated procedures and intensive computational effort,therefore simpler and accurate numerical approaches are always worthwhile to decrease armor development *** study aims to apply a hybrid method using FEM simulation and artificial neural network(ANN) analysis to approximate ballistic limit thickness for armor *** achieve this objective,a predictive model based on the artificial neural networks is developed to determine ballistic resistance of high hardness armor steels against 7.62 mm armor piercing *** this methodology,the FEM simulations are used to create training cases for Multilayer Perceptron(MLP) three layer *** order to validate FE simulation methodology,ballistic shot tests on 20 mm thickness target were performed according to standard Stanag ***,the successfully trained ANN(s) is used to predict the ballistic limit thickness of 500 HB high hardness steel *** show that even with limited number of data,FEM-ANN approach can be used to predict ballistic penetration depth with adequate accuracy.

关键词：人工神经网络有限元法穿透深度性能测定高速冲击有限元模拟 FEM模拟工具

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Effect of suction process on the growth of a convective gas bubble in diver's tissues

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International Journal of Biomathematics 2023年第2期16卷 177-197页

作者： Khaled G.Mohamed selim A.Mohammadein AhmedK.Abu-Nab Department of Mathematics Faculty of Science Banha UniversityBenhaEgypt Department of Mathematics Faculty of Science Tanta UniversityTantaEgypt Fluid Dynamics and Seismics Lab Moscow Institute of Physics and technology Dolgoprudny Moscow region141700Russia Mathematics and Computer Science Department Faculty of ScienceMenoufia University Shebin El-Kom32511Egypt

the motivation of this research is to study the effect of suction process on a growing gas bubble and concentration distribution around this bubble in tissues of divers who surface too *** effect of bubble motion is also *** method of combined variables is used to solve the problem by combining the radial and time variables into one variable by using a suitable similarity transformation that enables to divide the diffusion equation into two ODEs,the first concerns to concentration distribution and the other concerns to the bubble radius *** resultant formulae are valid for both growth stages whenever the ambient pressure is variable at ascending of the diver,or constant as the diving stops or at *** effects of physical parameters are discussed when applying suction process and show that the dominant parameter is the initial void *** research findings reveal the role of suction process to activate the systemic blood circulation and delay the growth of gas bubbles in the tissues and reduce the incidence of decompression illness(DCI).this research also provides evidenceand agrees with the previous experimental studies to support the use of suction therapy to reduce the DCI harmful effects.

关键词： Nitrogen bubbles suction therapy void fraction method of combined variables decompression illness

Influence of proton pump inhibitors on gastritis diagnosis and pathologic gastric changes

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World Journal of Gastroenterology 2015年第15期21卷 4599-4606页

作者： Soumana C Nasser Mahmoud Slim Jeanette G Nassif selim M Nasser School of Pharmacy Lebanese American University Institute of Neuroscience University of Granada Department of Pathology School of Medicine Lebanese American University

AIM: to investigate the influence of proton pump inhibitors(PPIs) exposure on the diagnosis of Helicobacter pylori(H. pylori) gastritis and intestinal ***: Chronic PPI use is associated with masking of H. pylori infection. Patients with H. pylori infection are predisposed to gastric and duodenal ulcers, and long-term infection with this organism has been associated with gastric mucosal atrophy and serious long-term complications, such as gastric lymphoma and adenocarcinoma. three hundred patients diagnosed with gastritis between January 2008 and April 2010 were included in our study. the computerized medical database of these patients was reviewed retrospectively in order to assess whether the type of gastritis diagnosed(H. pylori vs non-H. pylori gastritis) is influenced by PPI exposure. H. pylori density was graded as low, if corresponding to mild density following the Updated Sydney System, or high, if corresponding to moderate or severe densities in the Updated Sydney ***: Patients were equally distributed between males and females with a median age at the time of diagnosis of 50 years old(range: 20-87). the histological types of gastritis were classified as H. pylori gastritis(n = 156, 52%) and non-H. pylori gastritis(n = 144, 48%). All patients with non-H. pylori gastritis had inactive chronic gastritis. Patients with no previous PPI exposure were more likely to be diagnosed with H. pylori gastritis than those with previous PPI exposure(71% vs 34.2%, P testinal metaplasiawas more likely to be detected in the latter patients(1.4% vs 6.5%, P = 0.023). Multivariate analysis has also demonstrated that in the presence of previous PPI exposure(OR = 0.217, 95%CI: 0.123-0.385), GERD(OR = 0.317, 95%CI: 0.132-0.763, P = 0.01), alcohol intake(OR = 0.396, 95%CI: 0.195-0.804, P = 0.01), the detection of H. pylori was less likely. Chronic use of PPIs may mask H. pylori infections promoting the diagnosis of non-H. pylori gastritis and le

关键词： Gastritis Diagnosis Helicobacter pylori Proton pump inhibitors Social factors

Humidity and seasonality drives body size patterns in males of the bush cricket Isophya rizeensis Sevgili, 2003 （Orthoptera： tettigoniidae： Phaneropterinae）

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Insect Science 2014年第2期21卷 213-226页

作者： selim S. Cagasan Cagasan Karacaoglu A. Cem Kuyucu ismail K. Saelam Department of Biology Ecological Sciences Research Laboratories Faculty of Science Hacettepe University Beytepe 06800 Ankara Turkey

two primary patterns of body size variation have been recorded in ectotherms in relation to latitudinal/altitudinal shifts. In some, body size increases with increasing latitude/altitude whereas, in others, body size decreases with increasing latitude/altitude. this clinal variation is generally assumed to be caused by local adaptation to environmental conditions however the selective variable（s）（temperature, humidity, diet quality, etc.） is still heavily debated. Here we investigate geographic variation in body size of dark and pale color morphs of males of the bush-cricket lsophya rizeensis collected from 15 locations along an elevation gradient ranging from 350 to 2 500 m. Using an information theoretical approach we evaluate the relative support of four different hypotheses （the temperature size rule, the moisture gradient hypothesis, the seasonal constraint hypothesis, and the primary productivity hypothesis） explaining body size variation along the altitudinal gradient. Body size variation in pale color morphs showed a curvilinear relationship with altitude while dark color morphs showed no variation in body size. Body size variation in pale color morphs was highly correlated with precipitation and temperature seasonality values thus giving strong support for the moisture gradient and seasonal constraint hypothesis. Our results reinforce the importance of gradients in humidity and seasonality over temperature in the creation of altitudinal body size clines and the role of selection for resistance to stress factors in the establishment of these clines. Whether a body size cline is observed or not might also depend on the phenotypic properties of the individuals, like coloration.

关键词： altitude Bergmann's rule converse Bergmann's rule Flrtlna Valley,information-theoretic temperature size rule

Effect of Boron and Heat treatment on Mechanical Properties of White Cast Iron for Mining Application

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Journal of Iron and Steel Research International 2011年第11期18卷 31-39页

作者： Havva Kazdal Zeytin Hakan Yildirim Banu Berme selim Duduoglu Gürkan Kazdal Adem Deniz tUBItAK MRC Duduoglu Steel Casting Industry and trade Inc Co tuBItAK MRC Materials Institute Chemistry Metallurgy Faculty Istanbul technical University

Heat treatment methods were applied to white cast iron for improving the impact and wear resistance. Additionally, chemical composition optimization was made. Furthermore, the effect of boron addition on such applica- tions was investigated. Samples were investigated by using optical and electron microscope methods. Hardness, wear and impact tests were conducted. the results showed that the secondary carbides in the standard alloy were iron-enriched, needle-like carbides M3C when the boron-added alloy contained Fe23 （C, B）6 type, globular secondary carbides. It was concluded that heat treatment B provided higher wear and hardness properties, compared to the stand- ard heat treatment. Optimum mechanical properties were obtained by lower destabilisation temperatures and increasing temperature reduced the wear resistance and hardness.

关键词： white cast iron mining application impact resistance wear toughness

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H pylori:treatment for the patient only or the whole family?

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World Journal of Gastroenterology 2008年第8期14卷 1244-1247页

作者： Yavuz selim Sari Didem Can Vahit tunali Orhan Sahin Oguz Koc Omer Bender SB Istanbul training Hospital Istanbul Turkey SB Okmeydani training Hospital Istanbul Turkey

AIM： to compare the effects of treatment of H pyloriinfected individuals with the effects of treatment of individuals as well as all Hpylori-infected family members.MEtHODS： H pylori-positive patients with similar demographic specifications were prospectively randomized with respect to treatment, with a triple regimen of either patients and all Hpylori-positive family members living together （group Ⅰ ） or patients only （group Ⅱ）. Nine months after treatment, all patients were assessed for H pylori positivity.RESULtS： there were 70 H pylori-positive patients in each group; patients in groups Ⅰ and Ⅱ lived with 175 and 190 Hpylori-positive relatives, respectively. Age, sex and Hpylori positivity rate were similar in both groups of relatives. Nine months after 14 d standard triple therapy, Hpylori positivity was 7.1% in group I patients and 38.6% in group 11 patients [P 〈 0.01, OR = 8.61 95% confidence interval （CI）： 2.91-22.84].CONCLUSION： the present results indicate bad environmental hygienic conditions and close intra-familial relationships are important in H pylori contamination. these findings indicate all family members of H pyloripositive individuals should be assessed for H pylori positivity, particularly in developing countries where H pylori prevalence is high; they also suggest patients, their spouses and all H pyloN-positive family members of H pylori-positive individuals should be treated for H pylori infection.

关键词： H pylori Gastric adenocarcinoma Intrafamilial infections Gastric lymphoma Peptic ulcerdisease Non-ulcer dyspepsia

Effects of Helicobacter pylori infection on gastric epithelial cell kinetics in patients with chronic renal failure

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World Journal of Gastroenterology 2005年第45期11卷 7183-7187页

作者： selim Aydemir Binnaz Handan Ozdemir Gurden Gur Ibrahim Dogan Ugur Yilmaz Sedat Boyacioglu Department of Gastroenterology Department of Pathology

AIM： to evaluate the effects of Helicobacter pylori infection on gastric epithelial cell kinetics in patients with chronic renal failure （CRF）. MEtHODS： Forty-four patients were enrolled in this study and divided into four groups with respect to their Helicobacter pylori （H pylori） and CRF status. Groups were labeled as follows： la： normal renal function, H pylori negative （n = 12）, lb： normal renal function, H pylori positive （n = 11）, 2a： CRF, H pylori negative （n = 10）, 2b： CRF, H pylori positive （n = 11）. Upper gastrointestinal endoscopy was done in all the patients involved in the study. During endoscopical investigation, antral biopsy specimens were taken from each patient. In order to evaluate the cell apoptosis and proliferation in gastric epithelial cells, Bax and proliferating cell nuclear antigen （PCNA） labeling indexes （LI） were assessed with immunohistochemical staining method. RESULtS： For groups la, lb, 2a, and 2b, mean Bax LI was identified as 34.4±13.7, 44.1±16.5, 46.3±20.5, 60.7±13.8, respectively and mean PCNA LI was identified as 36.2±17.2, 53.6±25.6, 59.5±25.6, 67.2±22, respectively. When the one-way ANOVA test was applied, statistically significant differences were detected between the groups for both Bax LI （P = 0.004 〈0.01） and PCNA LI （P = 0.009 〈0.01）. When groups were compared further in terms of Bax LI and PCNA LI with tukey＇s HSD test for multiple pairwise comparisons, statistically significant difference was observed only between groups la and 2b （P = 0.006 〈0.01）.CONCLUSION： In gastric epithelial cells, expression of both the pre-apoptotic protein Bax and the proliferation marker PCNA increase with H pylori infection. this increase is more evident in patients with uremia. these findings suggest that uremia accelerates apoptosis and proliferation in gastric epithelial cells.

关键词： Helicobacter pylori Chronic renal failure Bax Proliferating cell nuclear antigen