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Effect of natural pozzolan content on the properties o engineered cementitious composites as repair material

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Frontiers of Structural and Civil Engineering 2018年第3期12卷 261-269页

作者： said CHOUCHA Amar BENYAHIA mohamed GHRICI mohamed said MANSOUR Geomaterials Laboratory Civil Engineering Department University Hassiba Benbouali of Chlef BP 151 Chief02000 Algeria

In order to determine the effect of Natural Pozzolan （NP） content on the mechanical properties and durability characteristics on Engineered Cementitious Composites （ECC） as repair material. This study focused on the evaluation of the most factors influencing compatibility between the repair material and the base concrete including mechanicals properties such as, compressive and flexural strengths, elastic modulus, capillary absorption and drying shrinkage. The experimental results showed that natural pozzolan reduces the compressive strength and the flexuraI strength of ECC at all ages. The elastic modulus of ECC was remarkably lower than that of normal-strength concrete. This lower ~oung＇s modulus is desirable for repair concrete, because it prevents the stresses induced by restrained shrinkage. In addition, the incorporation of high-volume natural pozzolan decreases significantly the coefficient of capillary absorption at long term and increases the drying shrinkage. Generally, based on the results obtained in the present experimental investigation, ECC can be used effectively as an overlay material over existing parent concrete.

关键词： natural pozzolan engineered cementitious composites mechanical strengths elastic modulus capillary absorption drying shrinkage

Effects of P301L-TAU on post-translational modifications of microtubules in human iPSC-derived cortical neurons and TAU transgenic mice

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Neural Regeneration Research 2025年第8期20卷 2348-2360页

作者： mohamed Aghyad Al Kabbani Christoph Köhler Hans Zempel Institute of Human Genetics Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany Center for Molecular Medicine Cologne(CMMC) University of CologneCologneGermany Center Anatomy Department ⅡMedical FacultyUniversity of CologneCologneGermany

TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the *** is missorted and aggregated in an array of diseases known as *** are essential for neuronal function and regulated via a complex set of post-translational modifications,changes of which affect microtubule stability and dynamics,microtubule interaction with other proteins and cellular structures,and mediate recruitment of microtubule-severing *** impairment of microtubule dynamics causes neuronal dysfunction,we hypothesize cognitive impairment in human disease to be impacted by impairment of microtubule *** therefore aimed to study the effects of a disease-causing mutation of TAU(P301L)on the levels and localization of microtubule post-translational modifications indicative of microtubule stability and dynamics,to assess whether P301L-TAU causes stability-changing modifications to *** investigate TAU localization,phosphorylation,and effects on tubulin post-translational modifications,we expressed wild-type or P301L-TAU in human MAPT-KO induced pluripotent stem cell-derived neurons(i Neurons)and studied TAU in neurons in the hippocampus of mice transgenic for human P301L-TAU(p R5 mice).Human neurons expressing the longest TAU isoform(2N4R)with the P301L mutation showed increased TAU phosphorylation at the AT8,but not the p-Ser-262 epitope,and increased polyglutamylation and acetylation of microtubules compared with endogenous TAU-expressing neurons.P301L-TAU showed pronounced somatodendritic presence,but also successful axonal enrichment and a similar axodendritic distribution comparable to exogenously expressed 2N4R-wildtype-TAU.P301L-TAU-expressing hippocampal neurons in transgenic mice showed prominent missorting and tauopathy-typical AT8-phosphorylation of TAU and increased polyglutamylation,but reduced acetylation,of microtubules compared with non-transgenic *** sum,P301L-TAU results in changes in micr

关键词： human induced pluripotent stem cell microtubules P301L pR5 mice TAU tauopathy tubulin code

SYNTHESIS,CHARACTERIZATION AND ENHANCED ELECTRICAL PROPERTIES OF CTAB-DIRECTED POLYANILINE NANOPARTICLES

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Chinese Journal of Polymer Science 2011年第2期29卷 181-190页

作者： Lal said Jan mohamed Ahmed Siddig Department of Physics Postgraduate College Mardan23200Khyber PakhtunkhwaPakistan School of Physics and Applied Physics Faculty of Science and TechnologyEL Neelain UniversityKhartoumSudan

Inverse microemulsion system of cetyltrimethylammonium bromide（CTAB） molecules is utilized for virtually monodispersed and controlled growth of HCl polyaniline（PANI） nanoparticles at room temperature（ca.300 K）.The templated electroconductive polymer reveals lamellar crystalline structure under X-ray diffraction signifying marked sub-chain alignment of the polymerized *** nanostructured polymer has spherically symmetric morphology in a size range of 2.0 nm to 6.0 nm under electron microscope *** permeation chromatography gives polydispersity index of 1.02 for nanostructured polymer in agreement with the size monodispersity transpired by electron *** *** conductivityσ_（dc） of PANI at room temperature is 10.11 S/cm whereas the variation of conductivity with temperature in the range 227-303 *** that the conducting mechanism can be considered as three-dimensional variable-range-hopping（3D-VRH）.UV-Vis spectrum indicates two broad absorption bands due to polaron formation that contributes to enhanced electrical conductivity of the *** fundamental absorption edge in the polymer is formed by direct allowed transitions to the extent that the optical band gap value was found to be 2.35 *** crystalline nanostructure and homogeneous doping attained in the cationic template of amphiphile are argued as contributing factors to the enhanced conductivity of the polymer.

关键词： Polyaniline Nanostructured Band gap energy Electrical conductivity

Position Control of Synchronous Motor Drive by Modified Adaptive Two-phase Sliding Mode Controller

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International Journal of Automation and computing 2008年第4期5卷 406-412页

作者： mohamed said Sayed Ahmed Automation Science and Electrical Engineering School Beijing University of Aeronautics and Astronautics

A modified adaptive two-phase sliding mode controller for the synchronous motor drive that is highly robust to uncertain- ties and external disturbances is proposed in this *** proposed controller uses two-phase sliding mode control (SMC) where the 1st phase mainly controls the system in steady states and disturbed states-it is a smoothing *** 2nd phase is used mainly in the case of disturbed ***,it is an autotuning phase and uses a simple adaptive algorithm to tune the gain of conventional variable structure control (VSC).The modified controller is useful in position control of a permanent magnet synchronous drive.

关键词： Reaching law adaptive control sliding mode control (SMC) chattering.

Contralateral eye study of refractive,topographic and aberrometric outcomes after femtosecond assisted Myo Ring implantation and DALK for management of keratoconus

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International Journal of Ophthalmology(English edition) 2018年第10期11卷 1621-1630页

作者： mohamed Omar Yousif Azza mohamed Ahmed said Department of Ophthalmology Faculty of Medicine Ain Shams University

AIM：To evaluate the efficacy of femtosecond laser assisted MyoRing intrastromal corneal implant and deep anterior lamellar keratoplasty （DALK） for management of moderate to advanced keratoconus regarding the degree of changes in visual acuity, refraction, corneal asphericity and ***：A prospective non comparative interventional case study was conducted in Ophthalmology Department,Ain Shams University Hospital in the period from January 2015 to February 2017. The study included 30 eyes of moderate to advanced keratoconus. MyoRing was implanted in one eye （Group Ⅰ） and DALK operation was performed in the contralateral eye of the same patient （Group Ⅱ）.Preoperative and 6mo post-operative uncorrected visual acuity（UCVA）, corrected distance visual acuity （CDVA）, spherical equivalent （SE）, corneal and refractive astigmatisms,keratometry and Q-value using topography images were acquired. Quality of vision was assessed in all eyes including total corneal, anterior corneal high order aberrations analysis at 5 mm pupil size and the Strehl ratio of point spread function （PSF） as an objective measure of ***：Mean postoperative UCVA, CDVA, SE, refractive astigmatism,keratometryreadingsandasphericity were statistically improved compared to preoperative parameters in both groups （P〈0.05）. Significant reduction of all corneal aberrations following both techniques（P〈0.05） was achieved except mean trefoil and mean PSF in Group Ⅰ （P〉0.05）. Postoperative corneal aberrations were significantly lower in Group Ⅱ compared to Group Ⅰ.A statistically significant negative correlation was found in Group Ⅰ between the mean change in CDVA （logMAR）and the mean preoperative and mean postoperative total corneal aberrations root mean square （RMS; r=-0.78,P=0.04）. Also a statistically significant negative correlation was found between mean preoperative coma RMS and mean post PSF （r=-0.86, P=0.01）. In Group Ⅱ, there was a statistically significant positive correlation between m

关键词： aberrations deep anterior lamellar keratoplasty femtosecond laser keratoconus MyoRing

Effect of different metal sulfate precursors on structural and catalytic performance of zirconia in dehydration of methanol to dimethyl ether

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燃料化学学报 2018年第1期46卷 67-74页

作者： Abd El-Aziz A.said mohamed Abd El-Aal Chemistry Department Faculty of ScienceAssiut University71516 AssiutEgypt

ZrO_2 was treated with 10% SO_4^(2-) from different metal sulfate precursors for methanol dehydration to dimethyl *** the samples exhibited tetragonal phase and no diffraction peaks corresponding to metal sulfates or metal oxides were *** FT-IR results revealed that there were different interactions between sulfate and ZrO_2,and this had a great effect on the surface area of the *** catalytic activity was measured over the catalysts in the temperature range of 100-300 ℃.The results revealed that sulfated zirconia with CuSO_4·5 H_2O and Al_2(SO_4)_3·16 H_2O showed the best catalytic *** maximum yield of DME ≈87% was obtained over CuSZ at a reaction temperature of 275 ℃.Moreover,the catalytic activity of the catalysts was correlated well with their surface acidity that measured by dehydration of isopropanol.

关键词： MSO 4/ZrO2 甲醇脱水 DME

Improved MPPT Control Strategy for PV Connected to Grid Using IncCond-PSO-MPC Approach

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CSEE Journal of Power and Energy Systems 2023年第3期9卷 1008-1020页

作者： Nora Kacimi Abdelhakim Idir said Grouni mohamed Seghir Boucherit Laboratoire de Commande de Processus ENP AlgerAlgiersAlgeria Electrical Engineering Department University of M’silaBP 28000M’silaAlgeria Boumerdes University Boumerdes35000BoumerdesAlgeria.He is now with the Tamaghasset UniversityAlgeria

This paper proposes a new hybrid maximum power point tracking(MPPT)control strategy for grid-connected solar systems based on Incremental conductance—Particle Swarm Optimization and Model Predictive Controller(IncCond-PSOMPC).The purpose of the suggested method is to create as much power as feasible from a PV system during environmental changes,then transfer it to the power *** accomplish this,a hybrid combination of incremental conductance(IncCond)and particle swarm optimization(PSO)is proposed to locate maximum power,followed by model predictive control(MPC)to track maximum power and control the boost converter to achieve high performance regardless of parameter variations.A two-level inverter,likewise,controlled by Model Predictive Control,is employed to inject the PV power *** this application,the MPC is based on minimizing the difference between the reference and prediction powers,which is computed to select the switching state of the *** proposed system is simulated and evaluated in a variety of dynamic conditions using Matlab/*** reveal that the proposed control mechanism is effective at tracking the maximum power point(MPP)with fewer power oscillations.

关键词： DC/DC boost converter grid-connected PV incremental conductance particle swarm optimization and model predictive controller(IncCond-PSO-MPC) maximum power point tracking(MPPT) photovoltaic(PV)

Desertification Detection in Makkah Region based on Aerial Images Classification

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Computer Systems Science & Engineering 2022年第2期40卷 607-618页

作者： Yahia said Mohammad Barr Taoufik saidani mohamed Atri Electrical Engineering Department College of EngineeringNorthern Border UniversityArarSaudi Arabia Laboratory of Electronics and Microelectronics(LR99ES30) Faculty of Sciences of MonastirUniversity of MonastirTunisia Department of Computer Sciences Faculty of Computing&Information TechnologyNorthern Border UniversityRafhaSaudi Arabia College of Computer Sciences King Khalid UniversityAbhaSaudi Arabia

Desertification has become a global threat and caused a crisis,especially in Middle Eastern countries,such as Saudi *** is one of the most important cities in Saudi Arabia that needs to be protected from *** vegetation area in Makkah has been damaged because of desertification through wind,floods,overgrazing,and global climate *** damage caused by desertification can be recovered provided urgent action is taken to prevent further degradation of the vegetation *** this paper,we propose an automatic desertification detection system based on Deep Learning *** images are classified using Convolutional Neural Networks(CNN)to detect land state variation in *** have been widely used for computer vision applications,such as image classification,image segmentation,and quality *** proposed CNN model was trained and evaluated on the Arial Image Dataset(AID).Compared to state-of-the-art methods,the proposed model has better performance while being suitable for embedded *** has achieved high efficiency with 96.47% *** light of the current research,we assert the appropriateness of the proposed CNN model in detecting desertification from aerial images.

关键词： Desertification detection deep learning convolutional neural networks(CNN) aerial images classification Makkah region

New model for standpipe pressure prediction while drilling using Group Method of Data Handling

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Petroleum 2022年第2期8卷 210-218页

作者： mohamed Riad Youcefi Ahmed Hadjadj Farouk said Boukredera Laboratory of Petroleum Equipment’s Reliability and Materials Faculty of Hydrocarbons and ChemistryUniversity M’hamed Bougara of BoumerdesAvenue de l’Independance35000BoumerdesAlgeria

The continuous evaluation of the measured Stand Pipe Pressure(SPP)against a modeled SPP value in real-time involves the automatic detection of undesirable drilling events such as drill string washouts and mud pump *** theoretical and experimental studies have been established to calculate the friction pressure losses using different rheological models and based on an extension of pipe flow correlations to an annular ***,it would not be feasible to employ these models for real-time applications since they are limited to some conditions and intervals of application and require input parameters that might not be available in real-time on each *** this study,The Group Method of Data Handling(GMDH)is applied to develop a trustworthy model that can predict the SPP in real-time as a function of mud flow,well depth,RPM and the Fan VG viscometer reading at 600 and 300 *** order to accomplish the modeling task,3351 data points were collected from two wells from Algerian *** and statistical assessment criteria disclosed that the model predictions are in excellent agreement with the experimental data with a coefficient of determination of 0.9666 and an average percent relative error less than 2.401%.Furthermore,another dataset(1594 data points)from well-3 was employed to validate the developed correlation for *** obtained results confirmed that the proposed GMDH-SPP model can be applied in real-time to estimate the SPP with high ***,it was found that the proposed GMDH correlation follows the physically expected trends with respect to the employed input ***,the findings of this study can help for the early detection of downhole problems such as drill string washout,pump failure,and bit balling.

关键词： Stand pipe pressure GMDH Drilling Mud flow Real-time monitoring Drill string washouts