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Experimental and numerical investigation of zirconium jet performance with different liner shapes design

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Defence Technology（防务技术） 2022年第1期18卷 12-26页

作者： Tamer elshenawy Qing-ming Li Ahmed Elbeih Technical Research Centre CairoEgypt The Uriversity of Manchester School of Mechanical Aerospace and Civil Engineering ManchesterUK Military Technical College Kobry ElkobbahCairoEgypt

This paper studies the shaped charge jet performance in terms of different liner shapes including conical,bell,hemispherical and bi-conical *** critical angles and the relevant flow velocities for the zir-conium liner material were calculated analytically and numerically using Autodyn *** relationship between the critical collapse angle and the flow velocity was determined for the conditions of jet formation and *** tests according to the standard testing procedures of APL-RP34(Section-I1)were performed to validate the numerical predictions of the jet performance of the studied *** was found that the four shaped charge liners all produced coherent jets with different *** penetration depth of the shaped charges with the bell and the bi-conical liner shapesincreased by 10.3%and 22%,respectively,while the crater diameter of shaped charge with hemispherical liner increased by 85%representing the formation of an explosively-formed-projectile(EF),when they are compared with the corresponding jet characteristics of a conical liner shaped ***оci 1cu.

关键词： Shaped dharge Zirconium Liner shape Penetration Concrete strength

High density thermite mixture for shaped charge ordnance disposal

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Defence Technology（防务技术） 2017年第5期13卷 376-379页

作者： Tamer elshenawy Salah Soliman Ahmed Hawass Technical Research Center Cairo Egypt

The effect of thermite mixture based on aluminum and ferric oxides for ammunition neutralization has been studied and tested. Thermochemical calculations have been carried out for different percentage of Al using Chemical Equilibrium Code to expect the highest performance thermite mixture used for shaped charge ordnance disposal. Densities and enthalpy of different formulations have been calculated and demonstrated. The optimized thermite formulation has been prepared experimentally using cold isostatic pressing technique, which exhibited relatively high density and high burning rate thermite mixture. The produced green product compacted powder mixture was tested against small caliber shaped charge bomblet for neutralization. Theoretical and experimental results showed that the prepared thermite mixture containing 33% of aluminum as a fuel with ferric oxide can be successfully used for shaped charge ordnance disposal.

关键词： Chemical Equilibrium Code which exhibited relatively high density

Influence of electric current intensity on the performance of electroformed copper liner for shaped charge application

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Defence Technology（防务技术） 2017年第6期13卷 439-442页

作者： Tamer elshenawy Salah Soliman Ahmed Hawwas Technical Research Center CairoEgypt

Electrolytic Copper used in the shaped charge liner manufacturing can be produced from acid solution using electro-deposition technique. The intensity of the applied electric current controls the quality of the produced copper grade. The electric current intensity within the electrolytic acidic solution cell with the minimum oxygen and sulfur elements in the produced copper was optimized and found to be 30-40 A/Ft^2. The elemental composition of the obtained electrolytic copper was determined using highend stationary vacuum spectrometer, while the oxygen was determined precisely using ELTRA ONH-2000 apparatus. Besides, SEM was used to investigate the shape of the copper texture inside the deposited layers and to determine the average grain size. New relations have been obtained between the applied current intensity and both the oxygen and sulfur contents and the average grain size of the produced copper. Experimental result showed that when the applied current density increases to a certain limit, the oxygen and sulfur content in the electrolytic copper decreases. Performance of the produced copper liner was investigated by the static firing of a small caliber shaped charge containing an electro-formed copper liners, where the penetration depth of the optimized electrolytic liner was enhanced by 22.7% compared to that of baseline non-optimized liner.

关键词： Electrolytic Copper SEM was used to investigate the shape of the copper texture

Investigation of a New Formula for Gurney Velocity Estimation

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火炸药学报 2018年第4期41卷 340-344页

作者： Tamer elshenawy Ahmed Elbeih Qing Ming Li Gamal M. Abdo Technical Research Centre Cairo Egypt Military Technical College Kobry Elkobbah Cairo Egypt The University of Manchester School of Mechanical Aerospace and Civil Engineering Manchester UK Mechanical Engineering Department Modern Acade

The formula for the analytical calculations of the shaped charge jetting parameters exhibit an explicit dependence upon the Gurney velocity of an explosive *** attempts have been done to approximate the characteristic constant 2E^(1/2) and to make its use more *** is shown herein that the characteristic Gurney velocity parameter depends on the ratio of the Chapman Jouguet-pressure to explosive impulse ratio by the formula:2E^(1/2)=0.2415(P_(CJ)/I_(SP)ρ_0)-970.76,where PCJis the Chapman Jouguet pressure(Pa),ISPis the specific impulse of the explosive used as a monopropellant(N·s/kg)andρois the explosive density(kg/m^3).The proposed empirical formula was found to be reasonable and quite accurate approximation that can be implemented over a wide range of explosives,where the maximum deviation between the measured and the calculated Gurney velocities was nearly 6%.Besides,the proposed approach has been used analytically to calculate the jet tip velocity of a small caliber shaped charge,which is measured *** difference between the measured and the calculated jet tip velocity was only 1.6%.

关键词：火药理论研究化学分析

Site specific probabilistic seismic hazard analysis at Dubai Creek on the west coast of UAE

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Earthquake Engineering and Engineering Vibration 2011年第1期10卷 143-152页

作者： ayman A. Shama Parsons Corporation 100 Broadway New York NY 10005 USA

A probabilistic seismic hazard analysis （PSHA） was conducted to establish the hazard spectra for a site located at Dubai Creek on the west coast of the United Arab Emirates （UAE）. The PSHA considered all the seismogenic sources that affect the site, including plate boundaries such as the Makran subduction zone, the Zagros fold-thrust region and the transition fault system between them; and local crustal faults in UAE. PSHA indicated that local faults dominate the hazard. The peak ground acceleration （PGA） for the 475-year return period spectrum is 0.17 g and 0.33 g for the 2,475-year return period spectrum. The hazard spectra are then employed to establish rock ground motions using the spectral matching technique.

关键词： seismic hazard PSHA subduction zone rock ground motion spectral matching logic tree fault

ELECTRICAL AND OPTICAL CHARACTERIZATION OF PMMA DOPED WITH Y_(0.0025)Si_(0.025)Ba_(0.9725)(Ti_((0.9))Sn_(0.1))O_3 CERAMIC

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Chinese Journal of Polymer Science 2010年第4期28卷 537-546页

作者： ayman S.Ayesh Department of Physics College of ScienceKing Faisal UniversityAl-AhssaSaudi Arabia

Poly（methylmetacrylate）（PMMA）/ Y0.0025Si0.025Ba0.9725 （Ti（0.9）Sn0.1）O3 （YBTS） composites were prepared at different weight ratios of YBTS （0 wt%, 5 wt%, 10 wt% and 20 wt% YBTS） in order to investigate effect of YBTS additions on the electrical and optical properties of PMMA host. The electrical properties （impedance, dielectric constant dielectric loss and AC conductivity） were studied in the frequency range 10 kHz-1 MHz and in temperature range 20-90℃. Upon increasing the contents of YBTS ceramic, we observed a reduction in the impedance and an increase in the dielectric constant, dielectric loss and AC conductivity of PMMA host. We also found that the relaxation process at high YBTS contents was due to relaxation in the ionic conductivity. The absorption coefficient （α） has been determined in the wavelength range 230-800 nm at room temperature for all YBTS-PMMA composites. Moreover, the addition of YBTS ceramic highly enhances the UV absorption of PMMA host especially below 300 nm. Addition of 20 wt% YBTS ceramic to PMMA host decreases the optical energy gap from 5 eV to 3.41 eV. Correlations between electrical, optical and SEM results are reported.

关键词： Electrical Optical PMMA, Ceramic Ferroelectric Composites

Study of Thermal Reactivity and Kinetics of HMX and Its PBX by Different Methods

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火炸药学报 2017年第2期40卷 24-32页

作者： Mohamed Abd-Elghany Thomas M.Klapotke Ahmed Elbeih Saeed Hassanein Tamer elshenawy Department Chemie Ludwig-Maximilians Universitat Munchen 81377 Munchen Germany Military Technical College Kobry Elkobbah Cairo Egypt Technical Research Center Cairo Egypt

Vacuum Stability Test(VST)was used to determine the thermal behavior and kinetic parameters of 1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX)and its mixture with hydroxyl-terminated polybutadiene(HTPB)as a binder coded as HMX/*** fitting and isoconversional method were applied to determine the kinetic parameters based on VST *** comparison,non-isothermal thermogravimetry analysis data(TGA)was also used to calculate the kinetic parameters by using Kissinger,OFW(Ozawa,Flynn,and Wall)and KAS(Kissinger-Akahira-Sunose)*** Kinetics and Technology Solution(AKTS)software was also used to determine the decomposition kinetics of the studied *** Scanning Calorimetry(DSC)was employed to determine the decomposition heat flow properties of the studied *** show that the activation energies obtained using VST results is 360.1kJ/mol for pure HMX and 186.9kJ/mol for HMX/*** activation energies obtained by the three different methods using TGA results are in the range of 360-368kJ/mol for pure HMX and 190-206kJ/mol for HMX/*** is concluded that values of kinetic parameters obtained by VST are close to that obtained by the different techniques using TG/DTG *** onset decomposition peak of HMX/HTPB is lower than that of HMX where the HTPB binder has negative effect on the thermal stability of *** results of all the applied techniques prove that HMX/HTPB has lower activation energy and heat release than the pure *** polymeric matrix has negative effect on the kinetic parameters of HMX.

关键词： HMX HMX/HTPB 火炸药质量管理研究工作 PBX

Influence of enhancing dynamic scapular recognition on shoulder disability,and pain in diabetics with frozen shoulder:A case report

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World Journal of Clinical Cases 2022年第33期10卷 12410-12415页

作者： ayman A Mohamed Basic Sciences Department Faculty of Physical TherapyBeni-Suef UniversityBeni Suef 34522Egypt Basic Sciences Department Faculty of Physical TherapyNahda UniversityBeni Suef 23146Egypt

BACKGROUND Frozen shoulder(FS)is a familiar *** with FS have more severe symptoms and a worse ***,this study investigated the influence of enhancing dynamic scapular recognition on shoulder disability and pain in diabetics with *** SUMMARY A Forty-five years-old male person with diabetes mellitus and a unilateral FS(stage II)for at least 3 mo with shoulder pain and limitation in both passive and active ranges of motion(ROMs)of the glenohumeral joint of≥25%in 2 directions participated in this *** person received dynamic scapular recognition exercise was applied to a diabetic person with a unilateral FS(stage II).The main outcome measures were upward rotation of the scapula,shoulder pain and disability index,and shoulder range of motion of flexion,abduction,and external *** dynamic scapular exercise was performed for 15 min/session and 3 sessions/wk lasted for 4 *** 4 wk of intervention,there were improvements between pre-treatment and post-treatment in shoulder pain,shoulder pain and disability index,shoulder ROM,and upward rotation of the *** This case report suggested that enhancing dynamic scapular recognition may improve shoulder pain and disability;upward rotation of the scapula;and shoulder ROM of shoulder abduction,flexion,and external rotation after 4 wk.

关键词： Scapular recognition Pain Range of motion Disability Frozen shoulder Case report

Analysing user daylight preferences in heritage buildings using virtual reality

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Building Simulation 2022年第9期15卷 1561-1576页

作者： Mohamed Marzouk Maryam ElSharkawy ayman Mahmoud Department of Structural Engineering Faculty of EngineeringCairo University12613GizaEgypt Department of Architecture Engineering Faculty of EngineeringCairo University12613GizaEgypt

Technology has always been creating effective ways to support human *** virtual reality(IVR)has emerged to engage users in a simulated world,and this has gained the interest of a wide variety of users in the heritage industry.A historical case study built in the early 19th century is considered for an adaptive reuse *** palace is located in Cairo,Egypt,and named after Prince Omar *** current palace state incorporates a smashed top-lit zone,which is being studied and analyzed for daylighting *** simulated distinct optimum skylight configurations are suggested for the redesign where the selection should not be based solely on simulation data,but should consider real-user *** daylight design criteria are previously based on simulation data that do not necessarily indicate the users'*** utilizing user interactive tools such as IVR to test daylight redesign options,a whole new dimension is *** this study,the VR users’survey data is statistically analyzed using Statistical Package for Social Sciences(SPSS),where results revealed that the assessment attributes succeeded in reflecting the users'preferences;which,motivated designers to consider potential users’daylight preferences in reused *** paper highlights the most significant emotional attributes that provide cost-effective and reliable information concerned with the performance of daylight in IVR before design *** study compares and analyzes the effect of three skylight designs(Cases A,B&C)on the users'perception before design implementation using(IVR)***-eight participants have contributed to the study,providing their feedback on six attributes namely:Pleasant,Contrasting,Brightness,Uniform Distribution,Visual Comfort,and *** attributes are evaluated for the three cases in space using five scale rating values to reveal that the"Pleasant"attribute is most reliable in the study to reflect th

关键词： daylight preferences heritage buildings rehabilitation immersive virtual reality statistical analysis