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effect of energy content of the nitraminic plastic bonded explosives on their performance and sensitivity characteristics

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Defence Technology（防务技术） 2019年第4期15卷 488-494页

作者： Svatopluk Zeman ahmed K. Hussein Marcela Jungova ahmed elbeih Institute of enegetic Materials Faculty of Chemical Technology University of Pardubice CZ-532 10 Pardubice Czechia Military Technical College Kobry Elkobbah Cairo Egypt

Information about the forty nine nitraminic plastic bonded explosives(PBXs)and different nitramines were *** of these PBXs are nitramines 1,3,5-trinitro-1,3,5-triazinane(RDX)and β-1,3,5,7-tetranitro-1,3,5-tetrazocane(β-HMX),cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole(bicyclo-HMX,BCHMX)and e-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(e-HNIW,CL-20)which are bonded by polyfluoro-elastomers,polydimethyl-siloxane,poly-glycidyl azide,polyisobutylene,polystyrene-butadiene,poly-acrylonitrile-butadiene and hydroxyl-terminated polybutadiene in addition to a melt cast compositions based on 2,4,*** thirty two of these PBXs the relationships are specified and analyzed between heats of their combustion and relative explosive strengths;by means of these relationships it might be possible to estimate,which groupings in the macromolecule of binder could be liable to their primary fission in the PBXs ***,for forty two of these explosives,the relationships are described and analyzed between their enthalpies of formation and impact sensitivities;here is especially attention paid to PBXs filled by *** rate constants from Vacuum Stability Test(VST)of four nitramines and twenty PBXs are introduced into relationships with their enthalpies of *** to all the mentioned cases,increasing of energy content of the studied explosives leads to increase of the relative explosive strength or initiation reactivity,*** with the opposite trend,the outputs of VST are for BCHMX,where in PBXs are matrices with the esteric plasticizers or the energetic poly-glycidyl *** of RDX or HMX,respectively,into the BCHX PBXs gives ternary PBXs whose thermal stability,in the sense of applied VST,is higher comparing to the original binary explosives.

关键词： enthalpy explosive strength Combustion Nitramines PBX Thermal stability

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High Gain Predictions for Ni-Like Ta Ions

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Chinese Physics Letters 2013年第11期30卷 80-83页

作者： Wessameldin S.Abdelaziz A.A.Farrag H.M.Hamed Mai e.ahmed National Institute of Laser enhanced Sciences Cairo UniversityGizaEgypt Faculty of Science Cairo UniversityGizaEgypt environmental Affairs Agency(eeAA) Egypt

Atomic structure data and effective collision strengths for 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10) and 54 fine-structure levels are contained in the configurations 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(9)4l(l=s,p,d,f)for the nickel-like Ta *** data are used in the determination of the reduced population for the 55 fine structure levels over a wide range of electron densities(from 10^(21) to 10^(23))and at various electron plasma *** gain coefficients for those transitions with a positive population inversion factor are determined and plotted against the electron density.

关键词： density nickel structure

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Closed Timelike Curves in Type Ⅱ Non-Vacuum Spacetime

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Communications in Theoretical Physics 2017年第2期67卷 189-191页

作者： Faizuddin ahmed Hindustani Kendriya Vidyalaya Bhangagarh Guwahati-781005 Assam Affiliated by CBSE New Delhi India

Here we present a cyclicly symmetric non-vacuum spacetime, admitting closed timelike curves(CTCs) which appear after a certain instant of time,i.e.,a time-machine spacetime. The spacetime is asymptotically flat, freefrom curvature singularities and a four-dimensional extension of the Misner space in curved spacetime. The spacetime is of type Ⅱ in the Petrov classification scheme and the matter field pure radiation satisfy the energy condition.

关键词： closed timelike curves Misner space pure radiation

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Nanofluid Flows Within Porous enclosures Using Non-Linear Boussinesq Approximation

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Computers, Materials & Continua 2021年第3期66卷 3195-3213页

作者： Sameh e.ahmed Dalal Alrowaili ehab Mahmoud Mohamed Abdelraheem M.Aly Department of Mathematics College of ScienceKing Khalid UniversityAbha62529Saudi Arabia Department of Mathematics South Valley UniversityQena83523Egypt Mathematics Department College of ScienceJouf UniversitySakakaSaudi Arabia electrical engineering Department College of EngineeringPrince Sattam Bin Abdulaziz UniversityWadi Addwasir11991Saudi Arabia electrical engineering Department Aswan UniversityAswan81542Egypt

In this paper,the Galerkin finite element method(FeM)together with the characteristic-based split(CBS)scheme are applied to study the case of the non-linear Boussinesq approximation within sinusoidal heating inclined enclosures filled with a non-Darcy porous media and *** enclosure has an inclination angle and its side-walls have varying sinusoidal temperature *** working fluid is a nanofluid that is consisting of water as a based nanofluid and Al2O3 as *** porous medium is modeled using the Brinkman Forchheimer extended Darcy *** obtained results are analyzed over wide ranges of the non-linear Boussinesq parameter 0≤ζ≤1,the phase deviation 00≤Φ≤1800,the inclination angle 00≤γ≤900,the nanoparticles volume fraction 0%≤φ≤4%,the amplitude ratio 0≤a≤1 and the Rayleigh number 104≤Ra≤*** results revealed that the average Nusselt number is enhanced by 0.73%,26.46%and 35.42%at Ra=104,105 and 106,respectively,when the non-linearBoussinesq parameter is varied from 0 to *** addition,rate of heat transfer in the case of a non-uniformly heating is higher than that of a uniformly ***-linear Boussinesq parameter rises the flow speed and heat transfer in an *** deviation makes clear changes on the isotherms and heat transfer rate on the right wall of an *** inclination angle varies the flow speed and it has a slight effect on heat transfer in an enclosure.

关键词： CBS scheme non-linear Boussinesq approximation nonuniformly heating non-darcy flow nanofluid

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Investigation of the behavior of slender reinforced concrete walls with complex conﬁgurations using nonlinearﬁnite element analysis

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Resilient Cities and Structures 2023年第1期2卷 120-142页

作者： Kamal A.ahmed Laura N.Lowes Dawn e.Lehman Lecturer Civil Engineering DepartmentErbil Polytechnic UniversityKurdistanIraq Senior Staffengineer Schnabel EngineeringSeattleWAUnited States Professor Department of Civil and Environmental EngineeringUniversity of WashingtonSeattleWAUnited States

Slender RC walls are used commonly in mid-and high-rise buildings to resist lateral loads arising from earthquakes and wind *** accommodate architectural constraints,facilitate construction,and maximize structural effi-ciency,the majority of these walls have complex configurations,comprising planar and non-planar wall elements that often include regular or irregular patterns of *** date most laboratory testing of slender RC walls has employed wall specimens with relatively simple configurations and without openings and coupling action which provides only limited understanding of the impact on performance of the variations in configuration and reinforcement detailing observed in real-world *** study presents a 3D continuum modeling approach to improve understanding of the behavior of walls with complex configurations and support recommendations for design of these *** wall data were used to calibrate the continuum-type modeling approach;experimental data characterizing the response of non-planar walls and walls with openings are used to validate the model.

关键词： RC Wall FeM Walls with openings Non-planar walls

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Syntheses of Some 3-[1′(1′H)-Substituent-pyrazol-5′-yl] benzo[5,6]coumarins

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Chinese Journal of Chemistry 2002年第7期20卷 670-675页

作者： e-LDeeN Ibrahim Mohey AL-WAKeeL el-Sayed Ismail el-MAWLA ahmed Gad Faculty of education Suez Canal University Port-said Egypt

3-[1′ (1′ H)-Substituent-pyrazol-5′-yl] benzo[5, 6] coumarins and3-(1′,2′-oxazol-5′-yl)benzo[5,6]coumarin were prepared via condensation of3-(2′-formyl-1′-chlorovinyl) benzo [5, 6] coumarin with hydrazine derivatives or *** of 3-[1′(1′ H)-pyrazol-5′-yl] benzo[5, 6] coumarin with alkyl halidcs, olefiniccompounds or acid chlorides are described.

关键词： heterocycle synthesis pyrazol-5′-ylbenzo [5, 6] coumarin alkylation atpyrazole nitrogen

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Voluntary tax compliance behavior of individual taxpayers in Pakistan

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Financial Innovation 2021年第1期7卷 453-475页

作者： Ibn e Hassan ahmed Naeem Sidra Gulzar Department of Commerce Bahauddin Zakariya UniversityMultanPakistan College of Business Administartion University of HailHailKingdom of Saudi Arabia

Governments settle their financial obligations and pay for the public expenditures largely through finances generated from *** many developing countries like Pakistan,the state authorities are still having difficulty to achieve tax *** literature has yet to traverse individual’s tax compliance behavior on developing *** current study,however,explores the relationships among voluntary tax compliance behavior of individual taxpayers with selected economic,social,behavioral and institutional *** individual tax compliance behavior is studied through the multi-perspective lenses of the theory of attribution,equity theory,expected utility theory,and social exchange *** design using the survey method was employed to collect data from 435 individual taxpayers through *** testing linkage between constructs,through mediation and moderation tests,structural equation modeling technique was *** results suggest that tax compliance simplicity has a larger impact on tax filing than perception about Government Spending and tax ***,perception of fairness significantly mediates the strengths between morale,simplicity,government spending and compliance behavior.

关键词： Compliance behavior Individual taxpayers Pakistan Perception of fairness Tax compliance simplicity Tax morale Voluntary tax

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MIMO performance enhancement of MIMO arrays using PCS-based near-field optimization technique

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Science China(Information Sciences) 2023年第6期66卷 170-185页

作者： Yipeng WANG Xiaoming CHeN Huiling PeI Wei e.I.SHA Yi HUANG ahmed A.KISHK School of Information and Communications engineering Xi'an Jiaotong University Key Laboratory of Micro-Nano electronic Devices and Smart Systems of Zhejiang Province College of Information Science and Electronic EngineeringZhejiang University Department of electrical engineering and electronics University of Liverpool Department of electrical and Computer engineering Concordia University

extensive efforts have been made in designing large multiple-input multiple-output(MIMO)arrays. Nevertheless, improvements in conventional antenna characteristics cannot ensure significant MIMO performance improvement in realistic multipath environments. Array decorrelation techniques have been proposed, achieving correlation reductions by either tilting the antenna beams or shifting the phase centers away from each other. Hence, these methods are mainly limited to MIMO terminals with small arrays. To avoid such problems, this work proposes a decorrelation optimization technique based on phase correcting surface(PCS)that can be applied to large MIMO arrays, enhancing their MIMO performances in a realistic(non-isotropic)multipath environment. First, by using a near-field channel model and an optimization algorithm, a near-field phase distribution improving the MIMO capacity is obtained. Then the PCS(consisting of square elements)is used to cover the array’s aperture, achieving the desired near-field phase *** examples demonstrate the effectiveness of this PCS-based near-field optimization technique. One is a1 × 4 dual-polarized patch array(working at 2.4 GHz)covered by a 2 × 4 PCS with 0.6λ center-to-center distance. The other is a 2 × 8 dual-polarized dipole array, for which a 4 × 8 PCS with 0.4λ center-to-center distance is designed. Their MIMO capacities can be effectively enhanced by 8% and 10% in single-cell and multi-cell scenarios, respectively. The PCS has insignificant effects on mutual coupling, matching, and the average radiation efficiency of the patch array, and increases the antenna gain by about 2.5 dB while keeping broadside radiations to ensure good cellular coverage, which benefits the MIMO performance of the *** proposed technique offers a new perspective for improving large MIMO arrays in realistic multipath in a statistical sense.

关键词： antenna correlation array antenna multiple-input multiple-output (MIMO) capacity

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Fuel cell stack design and modelling with a double-stage boost converter coupled to a single-phase inverter

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Clean energy 2024年第1期8卷 188-196页

作者： Basem e.elnagi ahmed M.Ismaiel Hany S.e.Mansour M.N.Abd-Alwahab electrical engineering Department Faculty of EngineeringSuez Canal UniversityIsmailia 41522Egypt

A comprehensive proton-exchange membrane fuel cell stack model was developed and integrated with a two-stage DC/DC boost *** was directly coupled to a single-phase(two levels-four pulses)inverter without a *** pulse-width modu-lation signal was used to independently regulate every converter *** converter was modelled using a MATLAB®/Simulink®environment and an appropriate voltage control *** analysis features of the suggested circuit were created and,through established experiments,the simulation results were verified.A single-phase(two levels-four pulses)inverter control circuit was tested and it produced a pure sinusoidal waveform with voltage *** matches the voltage of the network in terms of amplitude and frequency.A sinusoidal pulse-width modulation approach was performed using a single-phase(two levels-four pulses)pulse-width modulation *** results demonstrated an enhancement in the standard of the output wave and tuned the dead time with a reduction of 63μs compared with 180μs in conventional techniques.

关键词： PeM fuel cell pulse-width modulation single-phase inverter and double-stage DC/DC boost converter

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Price Prediction of Seasonal Items Using Time Series Analysis

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Computer Systems Science & engineering 2023年第7期46卷 445-460页

作者： ahmed Salah Mahmoud Bekhit esraa eldesouky ahmed Ali ahmed Fathalla Faculty of Computers and Informatics Zagazig UniversitySharkeya44523Egypt Information Technology Department the University of Technology and Applied SciencesIbriOman School of electrical and Data engineering University of Technology SydneySydney2007Australia College of Computer engineering and Sciences Prince Sattam Bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia Computer Science Department Faculty of Computers and InformaticsSuez Canal UniversityIsmailia41522Egypt Higher Future Institute for Specialized Technological Studies Cairo3044Egypt Department of Mathematics Faculty of ScienceSuez Canal UniversityIsmailia41522Egypt

The price prediction task is a well-studied problem due to its impact on the business *** are several research studies that have been conducted to predict the future price of items by capturing the patterns of price change,but there is very limited work to study the price prediction of seasonal goods(e.g.,Christmas gifts).Seasonal items’prices have different patterns than normal items;this can be linked to the offers and discounted prices of seasonal *** lack of research studies motivates the current work to investigate the problem of seasonal items’prices as a time series *** proposed utilizing two different approaches to address this problem,namely,1)machine learning(ML)-based models and 2)deep learning(DL)-based ***,this research tuned a set of well-known predictive models on a real-life *** models are ensemble learning-based models,random forest,Ridge,Lasso,and Linear ***,two new DL architectures based on gated recurrent unit(GRU)and long short-term memory(LSTM)models are ***,the performance of the utilized ensemble learning and classic ML models are compared against the proposed two DL architectures on different accuracy metrics,where the evaluation includes both numerical and visual comparisons of the examined *** obtained results show that the ensemble learning models outperformed the classic machine learning-based models(e.g.,linear regression and random forest)and the DL-based models.

关键词： Deep learning price prediction seasonal goods time series analysis

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