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Preparation and characterization of (CeO2)x-(Fe2O3)1-x nanocomposites:reduction kinetics and hydrogen storage

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Rare Metals 2020年第3期39卷 218-229页

作者： Shimaa G.Sayed waleed M.A.El Rouby Ahmed A.Farghali Materials Science and Nanotechnology Department Faculty of Postgraduate Studies for Advanced Science(PSAS)Beni-Suef UniversityBeni Suef62511Egypt

A series of nanosized CeO2-Fe2O3 mixed-oxide nanocomposites with different Ce4+/Fe3+molar ratios were successfully prepared by a co-precipitation *** surface area increased with Fe2O3 content increasing up to 60 wt%in the ***,with further increase in Fe2O3 content,the surface area began to *** reduction processes of the CeO2-Fe2O3 nanocomposites were studied in a hydrogen atmosphere at 300-600℃.The reduction rates increased by increasing both the temperature and Fe2O3 content in the *** microstructure of the reduced composites at 500℃illustrated the presence of a considerable number of macro-and *** activation energy values were calculated which were in the range of 3.56-5.37 kJ mol-1 at the initial stages(up to 35%reduction)and 5.21-10.2 kJ·mol-1 at the final stages(up to 80%reduction)of *** rate-controlling mechanisms in both the initial and final reduction stages were determined,and the initial reaction stage was controlled by combined gaseous diffusion and interfacial chemical reaction mechanisms for all the composites except for pure CeO2,which was controlled by a chemical reaction *** final reaction stage was controlled by a gaseous diffusion mechanism for some composites,while for the others it was controlled by combined gaseous diffusion and interfacial chemical reaction *** hydrogen sorption properties of the nanocomposites were studied by pressure composition isotherms using a volumetric *** storage in the nanocomposites increased by increasing the temperature because of the formation of oxygen vacancies which enhance atomic H adsorption and function as strong adsorption sites forming more metal hydride covalent bonds.

关键词： CeO2-Fe2O3 nanocomposite Reduction kinetics Reduction mechanism Hydrogen storage Oxygen vacancies

Learning Patterns from COVID-19 Instances

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Computer Systems Science & Engineering 2022年第2期40卷 765-777页

作者： Rehan Ullah Khan waleed Albattah Suliman Aladhadh Shabana Habib Department of Information Technology College of ComputerQassim UniversityBuraydahSaudi Arabia

Coronavirus disease,which resulted from the SARS-CoV-2 virus,has spread worldwide since early 2020 and has been declared a pandemic by the World Health Organization(WHO).Coronavirus disease is also termed *** affects the human respiratory system and thus can be traced and tracked from the Chest X-Ray ***,Chest X-Ray alone may play a vital role in identifying COVID-19 *** this paper,we propose a Machine Learning(ML)approach that utilizes the X-Ray images to classify the healthy and affected patients based on the patterns found in these *** article also explores traditional,and Deep Learning(DL)approaches for COVID-19 patterns from Chest X-Ray images to predict,analyze,and further understand this *** experimental evaluation of the proposed approach achieves 97.5% detection performance using the DL model for COVID-19 versus normal *** contrast,for COVID-19 versus Pneumonia Virus scenario,we achieve 94.5% accurate *** extensive evaluation in the experimental section guides and helps in the selection of an appropriate model for similar ***,the approach can be used for medical usages and is particularly pertinent in detecting COVID-19 positive patients using X-Ray images alone.

关键词： Coronavirus COVID-19 machine learning deep learning convolutional neural network

The use of facial expressions in measuring students’interaction with distance learning environments during the COVID-19 crisis

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Visual Informatics 2023年第1期7卷 1-17页

作者： waleed Maqableh Faisal Y.Alzyoud Jamal Zraqou Luminus Technical University College SAE Amman InstituteAmmanJordan Isra University AmmanJordan University of Petra AmmanJordan

Digital learning is becoming increasingly important in the crisis COVID-19 and is widespread in most *** proliferation of smart devices and 5G telecommunications systems are contributing to the development of digital learning systems as an alternative to traditional learning *** learning includes blended learning,online learning,and personalized learning which mainly depends on the use of new technologies and strategies,so digital learning is widely developed to improve education and combat emerging disasters such as COVID-19 *** the tremendous benefits of digital learning,there are many obstacles related to the lack of digitized curriculum and collaboration between teachers and ***,many attempts have been made to improve the learning outcomes through the following strategies:collaboration,teacher convenience,personalized learning,cost and time savings through professional development,and *** this study,facial expressions and heart rates are used to measure the effectiveness of digital learning systems and the level of learners’engagement in learning *** results showed that the proposed approach outperformed the known related works in terms of learning *** results of this research can be used to develop a digital learning environment.

关键词： E-learning COVID-19 Face-to-face learning Facial expressions Heart pulse

Glycated Hemoglobin HbA1c:Permittivity Experimental Applications with Some Mathematical Concepts,Temperature and Frequency Variations

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Journal of Renewable Materials 2022年第9期10卷 2335-2354页

作者： Soliman Abdalla Sherif Kandil waleed El-Shirbeeny Fatma Bahabri Department of Physics Faculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia Department of Materials Science Institute of Graduate Studies and ResearchAlexandria UniversityAlexandriaEgypt Department of Physics Faculty of ScienceJeddah UniversityJeddahSaudi Arabia

Diabetes disorder turns smoothly to be a global epidemic disorder and the glycated hemoglobin(HbA1c)starts to be an efficient marker of *** dielectric spectroscopy on different human normal-and diabetic-blood samples is used to characterize and to estimate the HbA1c concentration.“dc-”and ac-measurement of the complex conductivity in the temperature range from 280 K up to 320 K,and in the frequency range from one Hz up to 32 MHz have been *** thermal activation energy,ΔEσ,of dc-electric conductivity lies in the range 95 meV<ΔEσ<115 meV;while the thermal activation energy,ΔEτ,of RBCs relaxation time is aboutΔEτ=140 *** experimental data have been modeled by a physical-model and good fittings have been found between calculated and experimental *** effective number of charges,nG,T,is estimated after Cole and Cole *** has found that nG,T increases with both temperature,T,and with the glycation rate *** increase may shed some light on an effective and possible way to treat(and to detect)diabetes disorders via eliminating the excess electric charges produced by glycation *** present work sheds the light on the possible combination of focused ultrasound with magnetic resonance imaging to study the dielectric-thermal variations of glycated-RBCs,which can lead to very precise and non-invasive monitoring of glycation concentration in vivo and in vitro via magnetic resonance-thermometry.

关键词： Glycated-hemoglobin rate thermal characterization red blood cells RBCs relaxation of RBCs dielectric constant mathematical model

Impact of Fractures and Diagenesis on Reservoir Potential of Inner Ramp Paleocene Carbonates Exposed in Western Part of the Lesser Himalayas of Pakistan

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Journal of Earth Science 2023年第2期34卷 536-555页

作者： waleed Tariq Gohar Rehman Syed Ahsan Hussain Gardezi Nawaz Ikram National Center of Excellence in Geology University of PeshawarPeshawarKhyber Pakhtunkhwa 25120Pakistan Department of Geology University of PeshawarPeshawarKhyber Pakhtunkhwa 25120Pakistan Geological Survey of Pakistan Azad Jammu&Kashmir DirectorateMuzaffarabad 13100Pakistan Institute of Geology University of Azad Jammu&KashmirMuzaffarabad 13100Pakistan

The outcrop investigations provide a better comprehension to interrelate facies-diagenesis and fracture networks for the evaluation of reservoir potential of the carbonate *** this paper,we targeted Kahi-Section(Nizampur Basin)and Peeran Tangai-Section(Kalachitta Range)to analyze structural-kinematics,Discrete Fracture Network Modelling,microfacies identification and diagenesis to interpret their impact on reservoir potential of Lockhart Limestone(Paleocene).The structural grain within the study area mostly represents the typical east-west trending tight to overturned folds and north-dipping thrust faults that mimic the north-south Indo-Eurasian ***,a second phase of deformation related to east-west compressions also identified which rotated the axes of preexisting *** analysis revealed that extensional fractures are oriented at high angle to bedding and are differentiated into three orthogonal sets trending northeast-southwest,northwest-southeast and east-west,whereas,the shear fractures formed two conjugate sets trending *** Lockhart Limestone was deposited in the inner ramp setting and microfacies types are packstone,wackestone and wacke-packstone with seven sub-microfacies *** has been identified that the Lockhart Limestone has the heterogeneous distribution of diagenetic and tectonic features throughout its *** observed diagenetic sequence is micritization,calcite cementation,dissolution,neomorphism,pyritization and *** results highlight that open and partially filled fractures may provide an interconnected network to promote fluid mobility,leading to higher values of fracture *** porosity values of the pore matrix were greater than fracture,resulting a significant impact on reservoir storage *** contrast,a negative impact on reservoir potential has been shown by stylolites,veins and dissolution ***,based on the overall studies,the Lockhart Limestone reve

关键词： lockhart limestone discrete fracture network modelling facies-diagenesis reservoir potential Nizampur Basin petroleum geology

An energetic nano-fiber composite based on polystyrene and 1,3,5-trinitro-1,3,5-triazinane fabricated via electrospinning technique

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Defence Technology（防务技术） 2023年第9期27卷 1-8页

作者： Mahmoud Abdelhafiz Ahmed K.Hussein waleed F.Khalil Ahmed Elbeih Military TechnicalCollege(MTC) KobryElkobbahCairoEgypt Safety FuelCycleDepartment NRSRCEgyptianAtomicEnergyAuthority(EAEA)CairoEgypt

Electrospinning is a simple technique used to fabricate polymeric nano-fibrous *** nano-fibers have found a wide range of valuable applications in the biomedical ***,it has not been utilized with solid high explosives ***,the electrospinning technique has been used to fabricate polystyrene(PS)/1,3,5-trinitro-1,3,5-triazinane(RDX)composite *** governed electrospinning parameters,voltage,distance from the collector,flow rate,mandrel rotating speed,time,and solution concentration,that greatly affect the morphology of the obtained nanofibers were *** fabricated PS/RDX nano-fibers were characterized using scanning electron microscopy(SEM),X-ray diffractometer(XRD),and Fourier Transform Infrared(FTIR)*** impact and friction sensitivities of PS/RDX were also *** thermal behavior of the prepared composite and the pure materials were studied by the thermal gravimetric analysis technique(TGA).SEM results proved the fabrication of PS/RDX fibers in the nano-size via *** spectroscopy confirmed the existence of the characteristic functional groups of both PS and RDX in the composite *** sharp peaks showed the conversion of amorphous PS into crystalline shape via electrospinning and also confirmed the formation of PS/RDX *** PS fibers absorbed the heat and increased the onset decomposition of the pure RDX from 181.5 to 200.7℃in the case of PS/RDX ***,PS/RDX nano-fibers showed the relatively low impact and friction sensitivities of 100 J and 360 N *** results could introduce PS/RDX nanofibrous composite in the field of explosives detection with high levels of safety.

关键词： Electrospinning Nano-fibers 1,3,5-Trinitro-1,3,5-triazinane(RDX) Polystyrene(PS) Sensitivity

New solutions for four novel generalized nonlinear fractional fifth-order equations

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Journal of Ocean Engineering and Science 2024年第1期9卷 59-65页

作者： Mehmet Senol Lanre Akinyemi Henrietta Nkansah waleed Adel Nevsehir HacıBekta¸s Veli University Department of MathematicsNevsehirTurkey Department of Mathematics Lafayette CollegeEastonPennsylvaniaUSA Department of Mathematics University of Cape CoastCape CoastGhana Department of Mathematics and Engineering Physics Faculty of EngineeringMansoura UniversityEgypt UniversitéFrançaise dÉgypte Ismailia Desert RoadEl ShoroukCairoEgypt

In this paper,new four fifth-order fractional nonlinear equations are derived and *** frac-tional terms are defined in the conformable sense and these equations are then solved using two effective methods,namely,the sub-equation and the generalized Kudryashov *** methods were tested on the proposed models and succeeded in finding new solutions with different values of parameters.A graphical representation of some results is provided and proves the efficiency and applicability of the proposed methods for providing solutions with known physical *** methods are good candi-dates for solving other similar problems in the future.

关键词： Conformable derivative Generalized Kudryashov method Sub-equation method Riccati equation Solitons

Resource Allocation of 5G Network by Particle Swarm Optimization and Game Theory

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Resource Allocation of 5G Network by Particle Swarm Optimiza...

作者： Syed waleed 华南理工大学

学位级别：硕士

Given the high use of mobile communications,it is more recommended to deploy cellular networks whose diagrams allow the reintegration of *** 5G,the challenge is to increase the capacity and the throughput for a multitude of radiant base stations（BS）at minimum power in an urban ***,the coefficient（ICI）caused by the spectral overlap between base *** decreases network capacity,causing serious problems in the performance of User Equipment（UE）.Multiuser OFDMA networks include LTE/LTE-A networks and dense small-scale cell networks,the issues regarding the assignment of resource and power control discussed in this *** contribution of this thesis derived into the following two parts: In the first part,we propose the resource allocation algorithm based on particle swarm optimization（PSO）in the 5G *** minimize the computation costs,an objective function is formulated with some constraints,which denote the users’ Qo S requirements and *** solving the issue regarding composite nonlinear optimization,a unique population-built search algorithm is employed is referred to as the PSO.A PSO algorithm is presented to search the maximum allocation in each cell and corresponding resource *** the second part,we propose the power control of the 5G network based on Game theory（GT）.The GT,used for power control optimization of the 5G *** issue of power allotment is resolved by employing a decentralized GT procedure and the requirement of signaling messages interchange among distinct cells is *** resource and power are assigned to the group of nearby cells *** required information is received from the cells in the neighborhood after which the transmission power is altered to achieve the desired *** power control,a nondeterministic method called the stochastic algorithm can also be *** algorithm simulated for a total of 10 base stations in three ***,the results for GT are c

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Expansive Soil Stabilization by Bagasse Ash in Partial Replacement of Cement

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Journal of Renewable Materials 2023年第4期11卷 1911-1935页

作者： waleed Awadalseed Honghua Zhao Hemei Sun Ming Huang Cong Liu State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsDalian University of TechnologyDalian116023China State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian116023China Department of Geotechnical Engineering College of Civil EngineeringHunan UniversityChangsha410082China College of Civil Engineering Fuzhou UniversityFuzhou350116China

This study examined the effects of using bagasse ash in replacement of ordinary Portland cement(OPC)in the treatment of expansive *** study concentrated on the compaction characteristics,volume change,compressive strength,splitting tensile strength,microstructure,California bearing ratio(CBR)value,and shear wave velocity of expansive soils treated with *** bagasse ash replacement ratios were used to create soil *** varying curing times of 7,14,and 28 days,standard compaction tests,unconfined compressive strength tests,CBR tests,Brazilian split tensile testing,and bender element(BE)tests were carried *** to X-ray diffraction(XRD)investigations,quartz and crystobalite make up the majority of the minerals in bagasse *** ash contains a variety of grain sizes,including numerous fiber-shaped particles,according to a scanning electronic microscope(SEM)*** all of the treated specimens with various replacement ratios,the overall additive content has not *** results of the Brazilian split tensile tests demonstrate improved tensile strength for all specimens with various replacement proportions.A lower maximum dry density and a greater optimal water content would result from the substitution of bagasse *** the replacement ratio is not more than 20%,the CBR values of the parts replaced specimens are even higher than the cement *** results of BE testing on the treated soils show that there is significant stiffness anisotropy but that it steadily diminishes with curing time and replacement *** to the study,bagasse ash is a useful mineral additive,and the best replacement ratio(CBA20)is 20%.

关键词： Expansive soil bagasse ash cement calcium silicate hydrate(CSH) stiffness anisotropy