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Characterization of low-purity clays for geopolymer binder formulation

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International Journal of Minerals,Metallurgy and Materials 2014年第6期21卷 609-619页

作者： nasser Y.Mostafa Q.Mohsen A.El-maghraby Materials and Corrosion Lab (MCL) Department of Chemistry Faculty of Science Taif University Department of Chemistry Faculty of Science Suez Canal University Refractory & Ceramics Department National Research CenterDokki 12622 Cairo Egypt

The production of geopolymer binders from low-purity clays was investigated. Three low-purity clays were calcined at 750℃ for 4 h. The calcined clays were chemically activated by the alkaline solutions of NaOH and Na2SiO3. The compressive strength was measured as a function of curing time at room temperature and 85℃. The results were compared with those of a pure kaolin sample. An amorphous aluminosilicate polymer was formed in all binders at both processing temperatures. The results show that, the mechanical properties depend on the type and amount of active aluminum silicates in the starting clay material, the impurities, and the processing temperature.

关键词： geopolymers microstructure X-ray diffraction compressive strength clay

Effect of Notch Location on Fatigue Life Prediction of Strength Mismatched HSLA Steel Weldments

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Journal of Materials Science & Technology 2004年第2期20卷 129-135页

作者： S.Ravi V.Balasubramanian S.Nemat nasser Department of Manufacturing Engineering Annamalai University Annamalainagar-608 002. Tamil Nadu IndiaDepartment of Manufacturing Engineering Annamalai University Annamalainagar-608 002. Tamil Nadu IndiaCentre of Excellence for Advanced Materials University of California at San Diego La Jolla CA 92093-0416 USA

Welding of high strength low alloy steels (HSLA) involves usage of low, even and high strength filler materials (electrodes) than the parent material depending on the application of the welded structures and the availability of the filler material. In the present investigation, the fatigue crack growth behaviour of weld metal (WM) and heat affected zone (HAZ) regions of under matched (UM), equal matched (EM) and over matched (OM) joints has been studied. The base material used in this investigation is HSLA-80 steel of weldable grade. Shielded metal arc welding (SMAW) process has been used to fabricate the butt joints. Centre cracked tension (CCT) specimen has been used to evaluate the fatigue crack growth behaviour of the welded joints. Fatigue crack growth experiments have been conducted using servo hydraulic controlled fatigue testing machine at constant amplitude loading (R=0).A method has been proposed to predict the fatigue life of HSLA steel welds using fracture mechanics approach by incorporating influences of mismatch ratio (MMR) and notch location.

关键词： Shielded metal arc welding High strength low alloy steel Mismatch ratio Notch location Fatigue crack growth Fatigue life

Non-alcoholic steatohepatitis or metabolic-associated fatty liver:time to change

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Hepatobiliary Surgery and Nutrition 2021年第1期10卷 123-125页

作者： Gamal Shiha nasser Mousa Egyptian Liver Research Institute and Hospital(ELRIAH) MansouraEgypt Hepatology and Gastroenterology Unit Internal Medicine Department Tropical Medicine Department Faculty of MedicineMansoura UniversityMansouraEgypt

Non-alcoholic fatty liver disease(NAFLD)is a range of liver disease characterized by the occurrence of steatosis in greater than 5%of hepatocytes of people who drink tiny or no *** comprises,a benign non-alcoholic fatty liver(NAFL),and the more serious non-alcoholic steatohepatitis(NASH)described by steatosis,hepatocellular ballooning,lobular inflammation and lastly cirrhosis(1).

关键词： balloon NAFLD liver

Oncogenic BRAF^(V600E) induces microglial proliferation through extracellular signal-regulated kinase and neuronal death through c-Jun N-terminal kinase

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Neural Regeneration Research 2023年第7期18卷 1613-1622页

作者： Qing Ye Pranay Srivastava nasser Al-Kuwari Xiqun Chen Department of Neurology Massachusetts General HospitalHarvard Medical SchoolCharlestownMAUSA Department of Neurology Longhua HospitalShanghai University of Traditional Chinese MedicineShanghaiChina Aligning Science Across Parkinson’s(ASAP)Collaborative Research Network Chevy ChaseMDUSA

Activating V600E in v-Raf murine sarcoma viral oncogene homolog B(BRAF)is a common driver mutation in cancers of multiple tissue origins,including melanoma and ***^(V600E) has also been implicated in *** present study aims to characterize BRAF^(V600E) during cell death and proliferation of three major cell types of the central nervous system:neurons,astrocytes,and *** primary cultures(primary cortical mixed culture)and cell lines of glial cells(BV2)and neurons(SH-SY5Y)were ***^(V600E) and BRAF^(WT) expression was mediated by lentivirus or *** of downstream effectors(extracellular signal-regulated kinase 1/2 and JNK1/2)were achieved by *** astrocytes and microglia,BRAF^(V600E) induces cell proliferation,and the proliferative effect in microglia is mediated by activated extracellular signal-regulated kinase,but not c-Jun N-terminal *** medium from BRAF^(V600E)-expressing microglia induced neuronal *** neuronal cells,BRAF^(V600E) directly induces neuronal death,through c-Jun N-terminal kinase but not extracellular signal-regulated *** further show that BRAF-related genes are enriched in pathways in patients with Parkinson’s *** study identifies distinct consequences mediated by distinct downstream effectors in dividing glial cells and in neurons following the same BRAF mutational activation and a causal link between BRAF-activated microglia and neuronal cell death that does not require physical *** provides insight into a possibly important role of BRAF in neurodegeneration as a result of either dysregulated BRAF in neurons or its impact on glial cells.

关键词： astrocytes cell death cell proliferation inflammation microglia mutation neurons v-Raf murine sarcoma viral oncogene homolog B(BRAF)

How elevation and soil properties affect plant distribution patterns and species diversity in the Mediterranean mountain ecosystem of Al-Jabal Al- Akhdar, Libya

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Journal of Mountain Science 2024年第11期21卷 3683-3701页

作者： ABD EL-GHANI Monier AL BORKI Abd El-nasser Department of Botany and Microbiology Faculty of ScienceCairo UniversityGiza 12613Egypt Department of Biology Faculty of EducationUniversity of BenghaziBenghaziLibya

The objectives of this study were to assess distribution patterns of plant species richness,plant diversity and vegetation structure in relation to environmental factors along elevation gradient in Al-Jabal Al-Akhdar,*** each species,its growth form,chorological affinities,degree of occurrence,endemism status and originality were provided.A total of 534 taxa were generated from 70 families of the flowering plants,and 3 of the non-flowering plants were *** native flora of the study area was counted for 80.2%of the total indigenous taxa(465).The hump-shaped pattern of plant species richness was obtained,with the highest species richness at the mid-elevations,and both ends of the gradient have the *** annuals(300 species,56.2%)and non-succulent perennial herbs(165 species,30.9%)were the most dominant growth forms of the total species *** the elevation gradient,Asteraceae,Fabaceae,Poaceae,Lamiaceae and Apiaceae were the dominant families with the highest numbers of *** investigation recorded 31 endemic taxa,comprising 25 dicots and 6 monocots,primarily of Mediterranean origin,with most belonging to the Asteraceae and Lamiaceae *** chorotype was the dominant,whether pure(mono-),or combined with one(bi-and pluri-regional)or more(pluri-regional).Application of cluster analysis on the vegetation data yielded four cluster groups;each was linked to an elevation *** emphasized the importance of establishing conservation strategies to minimize human disturbance and safeguard relic habitats of Juniperus phoenicea *** its southern distribution limits in Africa,underlining the proactive management required for species *** application of Redundancy Analysis revealed that Shannon diversity index(H'),pH and Fe were the determinant soil factor in the mid-elevation levels(L2 and L3)whereas altitude,fine sand,HCO3,OM,and soil contents of Na,SO4 and Cl for the extreme levels(L1 and L4).

关键词： Altitudinal gradient Distribution patterns Floristic diversity Growth forms Libya Soil structure Vegetation analysis

Visual inspection of aircraft skin:Automated pixel-level defect detection by instance segmentation

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Chinese Journal of Aeronautics 2022年第10期35卷 254-264页

作者： Meng DING Boer WU Juan XU Abdul nasser KASULE Hongfu ZUO College of Civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Civil Aircraft Health Monitoring and Intelligent Maintenance of CAAC Nanjing 210016China

Skin defect inspection is one of the most significant tasks in the conventional process of aircraft *** paper proposes a vision-based method of pixel-level defect detection,which is based on the Mask Scoring ***,an attention mechanism and a feature fusion module are introduced,to improve feature ***,a new classifier head—consisting of four convolutional layers and a fully connected layer—is proposed,to reduce the influence of information around the area of the ***,to evaluate the proposed method,a dataset of aircraft skin defects was constructed,containing 276 images with a resolution of 960×720 *** results show that the proposed classifier head improves the detection and segmentation accuracy,for aircraft skin defect inspection,more effectively than the attention mechanism and feature fusion *** with the Mask R-CNN and Mask Scoring R-CNN,the proposed method increased the segmentation precision by approximately 21%and 19.59%,*** results demonstrate that the proposed method performs favorably against the other two methods of pixellevel aircraft skin defect detection.

关键词： Aircraft skin Automatic non-destructive testing Defect inspection Instance segmentation Machine vision

A direct power control of a DFIG based-WECS during symmetrical voltage dips

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Protection and Control of Modern Power Systems 2020年第1期5卷 36-47页

作者： Sara Mensou Ahmed Essadki Tamou nasser Badr Bououlid Idrissi Research Center of Engineering and Health Sciences and Technologies from ENSET Mohammed V UniversityRabatMorocco Research Center of Engineering and Health Sciences and Technologies from ENSIAS Mohammed V UniversityRabatMorocco Electromechanical Engineering Department of ENSAM Moulay Ismaïl UniversityMeknèsMorocco.

The Wind Energy Conversion System(WECS)based Doubly Fed Induction Generator(DFIG)has experienced a rapid development in the world,which leads to an increasing insertion of this source of energy in the electrical *** sudden and temporary drop of voltage at the network can affect the operation of the DFIG;the voltage dips produce high peak currents on the stator and rotor circuits,without protection,the rotor side converter(RSC)will suffer also from over-current limit,consequently,the RSC may even be destroyed and the generator be *** this paper a new Direct Power Control(DPC)method was developed,in order to control the stator powers and help the operation of the aero-generator during the faults grid;by injecting the reactive power into the network to contribute to the return of voltage,and set the active power to the optimum value to suppress the high peak *** DPC method was designed using the nonlinear Backstepping(BS)controller associated with the Lyapunov function to ensure the stability and robustness of the system.A comparison study was undertaken to verify the robustness and effectiveness of the DPC-BS to that of the classical vector control(VC)using Proportional-Integral(PI)*** were simulated under the Simulink®software.

关键词： Wind energy Doubly-fed induction aero-generator Voltage dips DPC strategy Backstepping technique Lyapunov function

Regularized machine learning through constraint swarm and evolutionary computation applied to regression problems

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International Journal of Intelligent Computing and Cybernetics 2014年第4期7卷 346-381页

作者： Ahmad Mozaffari nasser Lashgarian Azad Alireza Fathi Systems Design Engineering Department University of WaterlooWaterlooCanada Department of Mechanical Engineering University of TechnologyBabolIran

Purpose–The purpose of this paper is to demonstrate the applicability of swarm and evolutionary techniques for regularized machine ***,by defining a proper penalty function,regularization laws are embedded into the structure of common least square solutions to increase the numerical stability,sparsity,accuracy and robustness of regression *** regularization techniques have been proposed so far which have their own advantages and *** efforts have been made to find fast and accurate deterministic solvers to handle those regularization ***,the proposed numerical and deterministic approaches need certain knowledge of mathematical programming,and also do not guarantee the global optimality of the obtained *** this research,the authors propose the use of constraint swarm and evolutionary techniques to cope with demanding requirements of regularized extreme learning machine(ELM).Design/methodology/approach–To implement the required tools for comparative numerical study,three steps are *** considered algorithms contain both classical and swarm and evolutionary *** the classical regularization techniques,Lasso regularization,Tikhonov regularization,cascade Lasso-Tikhonov regularization,and elastic net are *** swarm and evolutionary-based regularization,an efficient constraint handling technique known as self-adaptive penalty function constraint handling is considered,and its algorithmic structure is modified so that it can efficiently perform the regularized *** well-known metaheuristics are considered to check the generalization capability of the proposed *** test the efficacy of the proposed constraint evolutionary-based regularization technique,a wide range of regression problems are ***,the proposed framework is applied to a real-life identification problem,*** the dominant factors affecting the hydrocarbon emissions of an automotive eng

关键词： Evolutionary computation Function approximation Hybrid systems

Energy exchange between charged relativistic fluids in f(T)gravity

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Communications in Theoretical Physics 2024年第10期76卷 106-118页

作者： Z Yousaf U A Khokhar nasser Bin Turki T Suzuki Department of Mathematics University of the PunjabQuaid-i-Azam CampusLahore-54590Pakistan Department of Mathematics College of ScienceKing Saud UniversityPO Box 2455Riyadh11451Saudi Arabia Department of Regional Management Faculty of ManagementFukushima CollegeFukushima 960-0181Japan

This study focuses on the effects of a polytropic fluid on a charged gravitational source within f(T)gravity,where T is the torsion *** investigate how the electromagnetic field affects the flow of energy in spherically symmetric and static celestial objects that contain relativistic *** using the gravitational decoupling technique,we analyze the effects of polytropic fluid on the dynamics of the gravitational source,accompanied by the matching of the interior geometry with an exterior at the hypersurfaceΣ.Finally,with the help of the TolmanⅡV solution,we observe the conduct of energy conditions with the existence of charge using f(T)field equations and got the intended outcomes.

关键词： complexity hydrodynamics anisotropy self-gravitating systems energy exchange