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Spatial Variability and Cartography of Maximum Annual Daily Rainfall under Different Return Periods in Northern Algeria

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Journal of Mountain Science 2015年第6期12卷 1403-1421页

作者： MEDDI Mohamed TOUMI samir National High School of Hydraulic (ENSH)

The estimation of precipitation quantiles has always been an area of great importance to meteorologists, hydrologists, planners and managers of hydrotechnical infrastructures. In many cases, it is necessary to estimate the values relating to extreme events for the sites where there is little or no measurement, as well as their return periods. A statistical approach is the most used in such cases. It aims to find the probability distribution that best fits the maximum daily rainfall values. In our study, 231 rainfall stations were used to regionalize and find the best distribution for modeling the maximum daily rainfall in Northern Algeria. The L-moments method was used to perform a regionalization based on discordance criteria and homogeneity test. It gave rise to twelve homogeneous regions in terms of LCoefficient of variation(L-CV), L-Skewness(L-CS) and L-Kurtosis(L-CK). This same technique allowed us to select the regional probability distribution for each group using the Z statistic. The generalized extreme values distribution(GEV) was selected to model the maximum daily rainfall of 10 groups located in the north of the steppe region and the generalized logistic distribution(GLO) for groups representing the steppes of Central and Western Algeria. The study of uncertainty by the bias and RMSE showed that the regional approach is acceptable. We have also developed maximum daily rainfall maps for 2, 5, 10, 20, 50 and 100 years return periods. We relied on a network of 255 rainfall stations. The spatial variability of quantiles was evaluated by semi-variograms. All rainfall frequency models have a spatial dependence with an exponential model adjusted to the experimental semi-variograms. The parameters of the fitted semi-variogram for different return periods are similar, throughout, while the nugget is more important for high return periods. Maximum daily rainfall increases from South to North and from West to East, and is more significant in the coastal areas of ea

关键词： Annual maximum daily rainfall Regionalisation L-moments Mapping Northern Algeria

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Re-evaluation of several heavy metals removal by natural limestones

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Frontiers of Chemical Science and Engineering 2014年第4期8卷 418-432页

作者： Ali SDIRI samir BOUAZIZ Laboratory of Water Energy and Environment National Engineering School University of Sfax Sfax 1173-3038 Tunisia

Different treatment technologies have been efficiently applied to remove heavy metals from waste- water. Efforts have been made to find out the most economic water treatment technology by using low cost and easily accessible natural materials. On the other hand, heavy metals are the most threatening groundwater contaminants because of their toxicity and harmful effects on human and biota. This review discusses the use of natural geological materials for heavy metal removal in aqueous systems. Special attention has been devoted to natural limestone through a systematic inventory of relevant published reports. The removal of toxic metals may include different mechanisms （e.g., physisorption, chemisorptions, precipitation, etc.）, depending on the physico-chemical properties of the material and the removed metal. Sorption of toxic metals （e.g., Pb, Cu, Cd, Zn, Cr, Hg, etc.） onto natural limestone involved precipitation of metal carbonate as a predominant removal process, but often subordinated by adsorption and ion exchange, depending on the physico-chemical properties of the studied limestone.

关键词： limestone heavy metals sorption waste-water passive treatment technology

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Numerical study on discharge characteristics influenced by secondary electron emission in capacitive RF argon glow discharges by fluid modeling

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Chinese Physics B 2018年第2期27卷 415-422页

作者：赵璐璐刘悦 Tagra samir Key Laboratory of Materials Modification by Laser Ion and Electron Beams (Ministry of Education) School of PhysicsDalian University of Technology School of Information Science and Engineering Dalian Polytechnic University

A one-dimensional（1D） fluid model of capacitive RF argon glow discharges between two parallel-plate electrodes at low pressure is employed. The influence of the secondary electron emission on the plasma characteristics in the discharges is investigated numerically by the model. The results show that as the secondary electron emission coefficient increases,the cycle-averaged electric field has almost no change; the cycle-averaged electron temperature in the bulk plasma almost does not change, but it increases in the two sheath regions; the cycle-averaged ionization rate, electron density, electron current density, ion current density, and total current density all increase. Also, the cycle-averaged secondary electron fluxes on the surfaces of the electrodes increase as the secondary electron emission coefficient increases. The evolutions of the electron flux, the secondary electron flux and the ion flux on the powered electrode increase as the secondary electron emission coefficient increases. The cycle-averaged electron pressure heating, electron Ohmic heating, electron heating, and ion heating in the two sheath regions increase as the secondary electron emission coefficient increases. The cycle-averaged electron energy loss increases with increasing secondary electron emission coefficient.

关键词： RF glow discharge secondary electron emission fluid model

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Effects of cathodic component of current on porosity and hardness characteristics of micro plasma oxidation(MPO) coatings on aluminum alloy

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中国有色金属学会会刊：英文版 2005年第1期15卷 113-118页

作者： samir Hamid Awad 钱翰城 School of Mechanical Engineering Chongqing University Chongqing 400044 China

Micro plasma oxidation(MPO) has recently been investigated as a novel, rapid and effective means to provide modified surfaces with improved properties of load bearing and wear resistance on light alloys particularly aluminum alloys. MPO is a multifactor-controlled process, these factors must be controlled to produce high quality coatings. The main research emphasis in MPO coating development over the past years seems to be the attainment of higher hardness levels and thick coatings. The porosity of MPO coating is the most complex phenomenon affecting the distribution, levels and the measurements of the hardness; and it is controlled by suitable selection of important parameters such as the electrical conditions. Ceramics coatings were synthesized on Al substrate by MPO to examine the effects of adding a cathodic phase alternated with anodic-cathodic current on the porosity and hardness characteristics of coatings by X-ray diffraction(XRD), scanning electron microscopy(SEM), and microhardness tester. The coatings produced by the combined mode are more dense and less porous than that by the anodic-cathodic mode. (Microhardness) test shows that the coatings produced by the combined mode exhibit both the highest hardness, and less reduction percentage in hardness with increasing the coatings thickness. These improvements become more significant for the polished and thicker coatings.

关键词：微观等离子体氧化铝合金硬度多孔材料

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Effects of gas pressure on plasma characteristics in dual frequency argon capacitive glow discharges at low pressure by a self-consistent fluid model

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Chinese Physics B 2017年第12期26卷 361-370页

A self-consistent fluid model for dual radio frequency argon capacitive glow discharges at low pressure is established. Numerical results are obtained by using a finite difference method to solve the model numerically, and the results are analyzed to study the effect of gas pressure on the plasma characteristics. It shows that when the gas pressure increases from 0.3 Torr （1 Torr=1.33322102 Pa） to 1.5 Torr, the cycle-averaged plasma density and the ionization rate increase; the cycle-averaged ion current densities and ion energy densities on the electrodes electrode increase; the cycle-averaged electron temperature decreases. Also, the instantaneous electron density in the powered sheath region is presented and discussed. The cycle-averaged electric field has a complex behavior with the increasing of gas pressure, and its changes take place mainly in the two sheath regions. The cycle-averaged electron pressure heating, electron ohmic heating, electron heating, and electron energy loss are all influenced by the gas pressure. Two peaks of the electron heating appear in the sheath regions and the two peaks become larger and move to electrodes as the gas pressure increases.

关键词： dual frequency gas pressure glow discharge

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Fault tolerant control based on neural network interval type-2 fuzzy sliding mode controller for octorotor UAV

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Frontiers of Computer Science 2016年第4期10卷 657-672页

作者： samir ZEGHLACHE Djamel SAIGAA Kamel KARA LASS Laboratory Departemenl: of Electronics Faculty of Technology University of MSila Msila 28000 Algeria SET Laboratory Departement of Electronics Faculty of Technology University of Blida Blida 09000 Algeria

In this paper, a robust controller for a six degrees of freedom （6 DOF） octorotor helicopter control is proposed in presence of actuator and sensor faults. Neural networks （NN）, interval type-2 fuzzy logic control （IT2FLC） approach and sliding mode control （SMC） technique are used to design a controller, named fault tolerant neural network interval type-2 fuzzy sliding mode controll,~r （FTNNIT2FSMC）, for each subsystem of the octorotor helicopter. The proposed control scheme allows avoiding difficult modeling, attenuating the chattering effect of the SMC, reducing the number of rules for the fuzzy controller, and guaranteeing the stability and the robustness of the system. The simulation results show that the FTNNIT2FSMC can greatly alleviate the chattering effect, tracking well in presence of actuator and sensor faults.

关键词： neural networks type-2 fuzzy logic sliding mode controller fault tolerant control octorotor helicopter

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Pancreatic pseudocyst

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World Journal of Gastroenterology 2009年第1期15卷 38-47页

作者： samir Habashi Peter V Draganov Department of Gastroenterology Hepatology and Nutrition University of FloridaGainesville Florida 32610 United States

Pancreatic pseudocysts are complications of acute or chronic pancreatitis. Initial diagnosis is accomplished most often by cross-sectional imaging. Endoscopic ultrasound with fine needle aspiration has become the preferred test to help distinguish pseudocyst from other cystic lesions of the pancreas. Most pseudocysts resolve spontaneously with supportive care. The size of the pseudocyst and the length of time the cyst has been present are poor predictors for the potential of pseudocyst resolution or complications, but in general, larger cysts are more likely to be symptomatic or cause complications. The main two indications for some type of invasive drainage procedure are persistent patient symptoms or the presence of complications (infection, gastric outlet or biliary obstruction, bleeding). Three different strategies for pancreatic pseudocysts drainage are available: endoscopic (transpapillary or transmural) drainage, percutaneous catheter drainage, or open surgery. To date, no prospective controlled studies have compared directly these approaches. As a result, the management varies based on local expertise, but in general, endoscopic drainage is becoming the preferred approach because it is less invasive than surgery, avoids the need for external drain, and has a high long-term success rate. A tailored therapeutic approach taking into consideration patient preferences and involving multidisciplinary team of therapeutic endoscopist, interventional radiologist and pancreatic surgeon should be considered in all cases.

关键词： Pancreatic pseudocyst Cyst Pancreatititis Endoscopic ultrasound Therapy

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Off-Pump Coronary Artery Bypass Grafting in Patients with Left Ventricular Dysfunction: Short-Term Results from a Single Center in Bangladesh

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World Journal of Cardiovascular Surgery 2024年第9期14卷 145-156页

作者： Muhit Abdullah Md. Abir Tazim Chowdhury Satyajit Sharma Rehana Akther Munama Magdum Munjerin Refat Synthee Md. Zafar-Al-Nimari Saikat Das Gupta Saleh Ahmed samir Kumar Biswas M. Quamrul Islam Talukder Farooque Ahmed Department of Cardiac Surgery National Heart Foundation Hospital and Research Institute (NHFH&RI) Dhaka Bangladesh Department of Cardiothoracic and Vascular Surgery Evercare Hospital Dhaka Dhaka Bangladesh Ispahani Islamia Eye Institute & Hospital Khamarbari Dhaka Bangladesh National Institute of Preventive and Social Medicine Dhaka Bangladesh Square Hospital Dhaka Bangladesh

Background: Off-pump coronary artery bypass grafting (OPCAB) is considered a safer alternative to on-pump surgery, especially in patients with left ventricular dysfunction (LVD). Objectives: This study assessed short-term outcomes and functional improvements in LVD patients post-OPCAB. Methods: The study included 200 coronary artery disease patients who underwent isolated off-pump coronary artery bypass grafting (OPCAB) at the National Heart Foundation Hospital and Research Institute between January 2019 and June 2020. Patients were categorized into Group 1, with a left ventricular ejection fraction (LVEF) of 30% - 39%, and Group 2, with an LVEF of 40% or higher. Echocardiographic assessments of left ventricular dimensions and ejection fraction were performed preoperatively, at discharge, and one month postoperatively. Results: In Group 1, preoperative left ventricular internal dimensions during diastole (LVIDd) and systole (LVIDs) were 53.48 ± 4.40 mm and 44.23 ± 3.93 mm, respectively, with a left ventricular ejection fraction (LVEF) of 35.28% ± 2.26%. At discharge, these values improved to 51.58 ± 4.04 mm (LVIDd), 41.23 ± 5.30 mm (LVIDs), and 39.25% ± 3.75% (LVEF). One month postoperatively, further improvements were observed: 46.29 ± 3.76 mm (LVIDd), 37.45 ± 3.68 mm (LVIDs), and 43.22% ± 4.67% (LVEF). Group 2 showed similar positive outcomes, with preoperative values of 47.09 ± 5.06 mm (LVIDd), 35.11 ± 5.25 mm (LVIDs), and 50.13% ± 7.25% (LVEF), improving to 42.37 ± 4.18 mm (LVIDd), 31.05 ± 4.19 mm (LVIDs), and 55.33% ± 7.05% (LVEF) at one month postoperatively. Both groups demonstrated significant improvements in left ventricular function and NYHA class, with most patients moving from class III/IV to I/II. Complications were minimal, and no mortality was observed. Conclusion: OPCAB is safe and effective for patients with LVEF 30% - 39% and LVEF ≥ 40%, providing significant short-term functional improvements without increased risk.

关键词： Off-Pump Coronary Artery Bypass Grafting Left Ventricular Dysfunction (LVD) Short-Term Outcomes

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The Communist Manifesto,170 Years Later

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学术界 2018年第11期 214-227页

作者： samir Amin French Marxian Economist Director of the Third World Forum

No text written in the mid-nineteenth century has held the road until today as well as the Communist Manifesto of *** is no any other text written in the middle of the 21th century which retained validity until this day as well as the Manifesto of the Communist *** today entire paragraphs of the text correspond to the contemporary reality even better than in *** from the premises which were hardly visible in the era,Marx and Engels drew the conclusions which the deployment of 170 years of history fully *** this article I will give further enlightening examples.

关键词： text written century premises

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Oscillation of third-order functional dynamic equations on time scales

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Science China Mathematics 2011年第12期54卷 2597-2614页

作者： SAKER samir H. College of Science Research Centre King Saud University P.O. Box 2455 Riyadh 11451 Saudi Arabia

We consider the nonlinear functional dynamic equation （p（t）[（r（t）x^△（t））^△]γ）^△＋q（t）f（x（τ（t））） =0, for t≥t0,on a time scale T, where γ〉 0 is the quotient of odd positive integers, p, r, τ- and q are positive rd-continuous functions defined on the time scale 1F, and lirut→∞ τ（t） = ∞. The main aim of this paper is to establish some new sufficient conditions which guarantee that the equation has oscillatory solutions or the solutions tend to zero as →∞ τ. The main investigation depends on the Riccati substitution and the analysis of the associated Riccati dynamic inequality. Our results extend, complement and improve some previously obtained ones. In particular, the results provided substantial improvement for those obtained by Yu and Wang [J Comput Appl Math, 225 （2009）, 531-540]. Some examples illustrating the main results are given.

关键词： oscillation third-order dynamic equations time scales

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