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构建AP-HTPB固体推进剂松弛模量主曲线的不同方法（英文）

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含能材料 2017年第10期25卷 810-816页

作者： Walid m adel 梁国柱北京航空航天大学宇航学院北京100083

分析了建立高氯酸铵-端羟基聚丁二烯(AP-HTPB)固体推进剂松弛模量主曲线的三种不同方法(Williams-Landel-Ferry(WLF)方法、Arrhenius方法和基本的时间-温度叠加(TTS)方法)。通过不同温度(-40,+20,+76℃)和10%常应变下1380s的应力松弛试... 详细信息

分析了建立高氯酸铵-端羟基聚丁二烯(AP-HTPB)固体推进剂松弛模量主曲线的三种不同方法(Williams-Landel-Ferry(WLF)方法、Arrhenius方法和基本的时间-温度叠加(TTS)方法)。通过不同温度(-40,+20,+76℃)和10%常应变下1380s的应力松弛试验得到了复合固体推进剂松弛模量。通过评估松弛模量,给出转移因子和松弛模量主曲线,最后通过确定系数(R^2)得出了最佳的拟合方法。结果表明,基本TTS方法可给出最佳拟合曲线,因为该方法不依赖外部材料常数和应用中的经验方程,而且该方法可以适用于任何黏弹性材料。但是,在应用有限元软件时,经常要求用材料常数来定义非线性黏弹性材料模型,这种情况下,目前研究结果表明,当给出合适的常数后,WLF和Arrhenius两种方法均可给出满意的结果,而且WLF方法更为准确,因此在AP-HTPB固体推进剂有限元分析中倾向于采用这种方法。

关键词：高氯酸铵-端羟基聚丁二烯(AP-HTPB) 主曲线松弛模量转移因子 W illiams-Landel-Ferry(WLF)方法 Arrhenius方法时间-温度叠加(TTS)方法

mineralogy and geochemistry of fine-grained Dahab stream sediments, Southeastern Sinai, Egypt: emphasis on the intergrowths of Fe–Ti oxides

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Acta Geochimica 2021年第6期40卷 871-894页

作者： adel A.Surour Ahmed.m.A.El-Kammar Ebtisam H.Arafa Hala m.Korany Petroleum and mining Geology Faculty of SciencesGalala University43511 New Galala CityEgypt Department of Geology Faculty of ScienceCairo UniversityGiza 12613Egypt

mineralogical and geochemical characteristics of stream sediments collected from 30 stations in the Dahab-Wadi Kid area(southeastern Sinai,Egypt)are *** studied sediments contain considerable amounts of heavy minerals,including abundant Fe–Ti oxides,with up to 25.94%index figure that measures the relative abundance of heavy minerals to light *** of the sediments and nature of Fe–Ti oxide intergrowths,in addition to some non-opaque heavy minerals,indicate multiple provenances with contributions from a variety of Neoproterozoic mafic to felsic *** amounts of heavy minerals are derived from schists that belong to the so-called Wadi Kid volcanosedimentary *** to the considerable contribution of the felsic intrusions represented by within-plate granites,the sediments are enriched in REE-bearing minerals(e.g.,monazite,cerianite,La-cerianite and allanite),V-bearing thorite,zircon,and a ZrO_(2) *** majority of Fe–Ti oxides are derived from the mafic intrusions,and they show evidence of pre-,syn-and post-depositional phases of alteration and formation of *** to the geochemical signature of the bulk silt fraction,there is remarkable enrichment of LREEs with distinct negative Eu anomaly,and this supports dominance of a provenance dominated by felsic intrusions(i.e.,the A-type within-plate granite and associated pegmatites).Also,the felsic provenance is responsible for slight abnormality of ∑PU+Th content(up to~37 ppm)and few anomalous samples bear uraniferous zircon and Ce-type *** present paper sheds light on the fertility of the Dahab stream sediments in some economic minerals for possible future exploitation,not for gold only,but for potential REEbearing minerals that are needed for a wide spectrum of modern technological industries.

关键词： Dahab stream sediments Silt fraction Fe-Ti oxides Textural variations Rees enrichment

Reliability-aware swarm based multi-objective optimization for controller placement in distributed SDN architecture

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Digital Communications and Networks 2024年第5期10卷 1245-1257页

作者： Abeer A.Z.Ibrahim Fazirulhisyam Hashim Aduwati Sali Nor K.Noordin Keivan Navaie saber m.E.Fadul Department of Computer and Communication Systems Engineering Faculty of Engineering Universiti Putra Malaysia Wireless and Photonics Networks Research Centre (WiPNET) Faculty of Engineering Universiti Putra Malaysia Department of Communication and Computer Engineering College of Engineering and Medical Sciences School of Computing and Communications Lancaster University Department of Electrical and Electronics Engineering Faculty of Engineering Universiti Putra Malaysia

The deployment of distributed multi-controllers for Software-Defined Networking(SDN) architecture is an emerging solution to improve network scalability and ***,the network control failure affects the dynamic resource allocation in distributed networks resulting in network disruption and low ***,we consider the control plane fault tolerance for cost-effective and accurate controller location models during control plane *** fault-tolerance strategy has been applied to distributed SDN control architecture,which allows each switch to migrate to next controller to enhance network *** this paper,the Reliable and Dynamic mapping-based Controller Placement(RDmCP) problem in distributed architecture is framed as an optimization problem to improve the system reliability,quality,and *** considering the bound constraints,a heuristic state-of-the-art Controller Placement Problem(CPP) algorithm is used to address the optimal assignment and reassignment of switches to nearby controllers other than their regular *** algorithm identifies the optimal controller location,minimum number of controllers,and the expected assignment costs after failure at the lowest effective cost.A metaheuristic Particle Swarm Optimization(PSO)algorithm was combined with RDmCP to form a hybrid approach that improves objective function optimization in terms of reliability and *** effectiveness of our hybrid RDmCP-PSO was then evaluated using extensive experiments and compared with other baseline *** findings demonstrate that the proposed hybrid technique significantly increases the network performance regarding the controller number and load balancing of the standalone heuristic CPP algorithm.

关键词： Software defined networking Dynamic mapping Particle swarm optimization Reliability multi-objective optimization Evolutionary

multiphysics simulation of VVER-1200 fuel performance during normal operating conditions

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Nuclear Science and Techniques 2023年第2期34卷 139-152页

作者： Khaled m.Yassin mohamed H.Hassan mohammad m.Ghoneim mostafa S.Elkolil adel Alyan Said A.Agamy Nuclear Research Center Egyptian Atomic Energy AuthorityAbo Zaabal 13759CairoEgypt Department of Nuclear and Radiological Engineering Faculty of EngineeringAlexandria UniversityAlexandria 21544Egypt Faculty of Engineering Egyptian Russian UniversityBadr 11829Egypt

Nuclear fuel performance modeling and simulation are critical tasks for nuclear fuel design optimization and safety analysis under normal and transient *** performance is a complicated phenomenon that involves thermal,mechanical,and irradiation mechanisms and requires special multiphysics *** this study,a fuel performance model was developed using the COmSOL multiphysics *** modeling was performed for a 2D axis-symmetric geometry of a UO2fuel pellet in the E110 clad for VVER-1200 *** modeling considers all relevant phenomena,including heat generation and conduction,gap heat transfer,elastic strain,mechanical contact,thermal expansion,grain growth,densification,fission gas generation and release,fission product swelling,gap/plenum pressure,and cladding thermal and irradiation *** model was validated using a code-to-code evaluation of the fuel pellet centerline and surface temperatures in the case of constant power,in addition to validation of fission gas release(FGR)*** prediction proved that the model could perform according to previously published VVER nuclear fuel performance parameters.A sensitivity study was also conducted to assess the effects of uncertainty on some of the model *** model was then used to predict the VVER-1200 fuel performance parameters as a function of burnup,including the temperature profiles,gap width,fission gas release,and plenum pressure.A compilation of related material and thermomechanical models was conducted and included in the modeling to allow the user to investigate different material/performance *** the model was developed for normal operating conditions,it can be modified to include off-normal operating conditions.

关键词： VVER-1200 Fuel performance COmSOL code Zr-1%Nb cladding UO2 fuel rod

Is the pain in chronic pancreatitis of neuropathic origin? Support from EEG studies during experimental pain

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World Journal of Gastroenterology 2008年第25期14卷 4020-4027页

作者： AsbjФrn m Drewes maciej Gratkowski saber AK Sami Georg Dimcevski Peter Funch-Jensen Lars Arendt-Nielsen Department of Gastroenterology Aalborg University Hospital Center for Sensory-motor Interactions (SmI) Department of Health Science and Technology Aalborg University Department of Gastroenterology Haukeland University Hospital Department of Surgical Gastroenterology L Aarhus University Hospital

AIm: To prove the hypothesis that patients with chronic pancreatitis would show increased theta activity during painful visceral stimulation. mETHODS: Eight patients and 12 healthy controls underwent an experiment where the esophagus was electrically stimulated at the pain threshold using a nasal endoscope. The electroencephalogram (EEG) was recorded from 64 surface electrodes and "topographic matching pursuit" was used to extract the EEG information in the early brain activation after stimulation. RESULTS: A major difference between controls and patients were seen in delta and theta bands, whereas there were only minor differences in other frequency bands. In the theta band, the patients showed higher activity than controls persisting throughout the 450 ms of analysis with synchronous brain activation betweenthe channels. The main theta components oscillated with 4.4 Hz in the patients and 5.5 Hz in the controls. The energy in the delta (0.5-3.5 Hz) band was higher in the controls, whereas the patients only showed scattered activity in this band. CONCLUSION: The differences in the theta band indicate that neuropathic pain mechanisms are involved in chronic pancreatitis. This has important implications for the understanding and treatment of pain in these patients, which should be directed against drugs with effects on neuropathic pain disorders.

关键词： Chronic Pancreatitis Neuropathic pain Esophagus Thalamocortical system Electroence-phalography

Sensitive and fast response ethanol chemical sensor based on as-grown Gd_2O_3 nanostructures

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Journal of Rare Earths 2015年第2期33卷 214-220页

作者： m.m.Abdullah mohammed m.Rahman Houcine Bouzid m.Faisal Sher Bahadar Khan S.A.Al-Sayari adel A.Ismail Promising Centre for Sensors and Electronic Devices (PCSED) College of Science and Arts Najran University P.O. Box-1988Najran 11001 Saudi Arabia Center of Excellence for Advanced materials Research (CEAmR) & Chemistry Department King Abdulaziz University P.O. Box 80203Jeddah 21589 Saudi Arabia Laboratory of Ferroelectric materials Faculty of Sciences of Sfax Route Soukra Km 35B.P. 802 F-3018 Sfax Tunisia College of Science and Arts-Sharoura Najran University P.O. Box-1988Najran 11001 Saudi Arabia Central metallurgical Research and Development Institute (CmRDI) P.O.Box: 87 Helwan 11421 Cairo Egypt

Well crystalline gadolinium oxide（Gd2O3） nanostructures were grown by annealing the hydrothermally as-prepared nanostructures without using any template. microscopic studies of Gd2O3 nanostructures were recorded along the [111] direction due to the clearly resolved interplanar distance d（222）-0.31 nm of the cubic crystal structure Gd2O3. Sensing mechanism of Gd2O3 as efficient electron mediator for the detection of ethanol was explored. As-fabricated sensor demonstrated the high-sensitivity of -0.266 μAm/m/cm2 with low detection limit（-52.2 μmol/L） and correlation coefficient（r^2, 0.618）. To the best of our knowledge, this was the first report for the detection of ethanol using as-grown（at 1000 oC） Gd2O3 nanostructures by simple and reliable Ⅰ-Ⅴ technique and rapid assessment of the reaction kinetics（in the order of seconds）. The low cost of the starting reagents and the simplicity of the synthetic route made it a promising chemical sensor for the detection of various toxic analytes, which are not environmentally safe.

关键词： growth Gd2O3 nanostructures ethanol Ⅰ-Ⅴ technique chemical sensing rare earths

Two Bioinspired mobile manipulators with Rolling Locomotion

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Journal of Bionic Engineering 2016年第1期13卷 48-58页

作者： saber mahboubi Heydarabad mir masoud Seyyed Fakhrabadi Steve Davis Samia Nefti-meziani School of Computing Science & Engineering University of Salford Manchester The Crescent M5 4WT UK School of mechanical Engineering College of Engineering University of Tehran Tehran Iran

This paper deals with two novel structures for mobile robots. The original inspiration of the robots comes from a sala- mander and a specific kind of spiders. Our robots have some especial moving capabilities causing to increase the robot ma- neuverability. Indeed, the capability of rolling motion is added to ordinary quadruped robots. This capability causes increment in maneuvering of the robots. manipulators can be embedded into the robots to add the ability of transferring materials into the shell and conducting some tasks such as repairing. In this paper, after analysis of motion principles of the rolling robots, their dynanlic equations are derived. Different simulations of two bioinspired mobile robots are presented in order to scrutinize various capabilities of the proposed designs. Walking capabilities of the robots and their advantages are discussed in detail. The comprehensive simulation results of the robots in various motion modes are presented. Finally the first prototype is introduced to verify the motion mechanisms.

关键词： bionics rolling robot quadruped robot Lagrange equations

LES of rotating film-cooling performance in a 1-1/2 turbine stage

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Propulsion and Power Research 2019年第2期8卷 85-107页

作者： Nabeel Al-Zurfi adel Nasser mechanical Engineering Department Faculty of EngineeringUniversity of KufaNajafIraq School of mechanical Aerospace and Civil EngineeringThe University of ManchesterManchesterM139PLUK

The large eddy simulation method was employed to investigate the film-cooling performance in a low-speed rotor blade of a 1-1/2 turbine *** rotor blade height and axial chord length were 99 mm and 124.3 mm,*** rows of film holes were placed on the rotor blade surface,one each on the pressure and suction *** row had three cylindrical film holes with a diameter of 4 mm and a tangential injection angle of 28°on the pressure side and 361 on the suction *** Reynolds number was fixed at Re=1.92×10^(5)and the coolant-to-mainstream density ratio(DR)was about *** were carried out for three different rotating speeds of 1800,2100,and 2400 rpm with the blowing ratio(BR)varying from 0.3 to *** commercial CFD code STAR-CCm+was used to run the simulations using the WALE subgrid-scale model for modelling the *** results show that on the pressure side,the film coverage and filmcooling effectiveness decrease with increasing rotation number(Ro)and increase with increasing blowing ratio(BR).A higher Ro and lower BR result in a stronger film *** film injection with higher BR produces better film *** film deflects centrifugally where the deflection becomes greater with increasing *** the suction side,the film coverage and film-cooling effectiveness increase with increasing either Ro or BR and a centripetal deflection of the film is *** deflection of the film path could be amplified by either increasing the Ro at a constant BR or decreasing the BR at a constant *** the rotation weakens the film deflection towards the hub on the suction ***,it was found that both rotation number and blowing ratio play significant roles in determining the film-cooling effectiveness distributions of the rotor blade surface.

关键词： Rotor blade Large eddy simulation Film-cooling effectiveness Turbulence Rotation Subgrid-scale

Automatic Detection of COVID-19 Using a Stacked Denoising Convolutional Autoencoder

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Computers, materials & Continua 2021年第12期69卷 3259-3274页

作者： Habib Dhahri Besma Rabhi Slaheddine Chelbi Omar Almutiry Awais mahmood adel m.Alimi College of Applied Computer Sciences(CACS) King Saud UniversityRiyadh11543Saudi Arabia Faculty of Sciences and Technology of Sidi Bouzid University of KairouanKairouanTunisia National School of Engineers(ENIS) University of SfaxTunisia Department of Computer Sciences College of Sciences and Arts in UnaizahQassim UniversityAl-QassimKingdom of Saudi Arabia

The exponential increase in new coronavirus disease 2019(COVID-19)cases and deaths has made COVID-19 the leading cause of death in many ***,in this study,we propose an efficient technique for the automatic detection of COVID-19 and pneumonia based on X-ray images.A stacked denoising convolutional autoencoder(SDCA)model was proposed to classify X-ray images into three classes:normal,pneumonia,and *** SDCA model was used to obtain a good representation of the input data and extract the relevant features from noisy *** proposed model’s architecture mainly composed of eight autoencoders,which were fed to two dense layers and Softmax *** proposed model was evaluated with 6356 images from the datasets from different *** experiments and evaluation of the proposed model were applied to an 80/20 training/validation split and for five cross-validation data splitting,*** metrics used for the SDCA model were the classification accuracy,precision,sensitivity,and specificity for both *** results demonstrated the superiority of the proposed model in classifying X-ray images with high accuracy of 96.8%.Therefore,this model can help physicians accelerate COVID-19 diagnosis.

关键词： Stacked autoencoder augmentation multiclassification COVID-19 convolutional neural network