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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

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

Enhancing the explosive characteristics of a Semtex explosive by involving admixtures of BCHMX and HMX

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Defence Technology（防务技术） 2020年第2期16卷 487-492页

作者： Ahmed Elbeih Ahmed K.Hussein tamer elshenawy Svatopluk Zeman Sara M.Hammad Ahmad Baraka Mohamed A.Elsayed Mohamed Gobara Hesham Tantawy Military Technical College Kobry ElkobbahCairoEgypt Technical Research Center CairoEgypt Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of PardubiceCzech Republic Faculty of Pharmacy University of CairoGizaEgypt

A well-known ternary plastic explosive,Czech Semtex 1H,contains a mixture of PETN and RDX softened by *** this work,BCHMX was used to replace PETN in Semtex 1H to form Sem-BC+*** addition,another mixture based on BCHMX and HMX as energetic fillers bonded by the polymeric matrix of Semtex 1H(Sem-BC+HMX)was *** particle size distribution of each individual explosive was determined to obtain the optimum mixing *** and impact sensitivities were *** velocity of detonation was reported practically and the detonation properties were calculated by EXPLO5 *** explosive strength of each sample was measured by the ballistic mortar *** conclusion confirms that the velocity of detonation of Sem-BC+HMX was the highest in comparison with the prepared ***-BC+RDX has the least impact and frictions ***-BC+RDX has higher detonation velocity,detonation properties and explosive strength than Semtex *** of BCHMX in Semtex 1H as a replacement for PETN is the candidate to produce a high performance advanced Czech plastic explosive.

关键词： Semtex Explosives Combustion Sensitivity Detonation Explosive strength

Robust Designs Through Risk Sensitivity:An Overview

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Journal of Systems Science & Complexity 2021年第5期34卷 1634-1665页

作者： BASAR tamer Coordinated Science Laboratory University of Illinois1308 West MainUrbanaIL 61801USA.

This is an overview paper on the relationship between risk-averse designs based on exponential loss functions with or without an additional unknown(adversarial)term and some classes of stochastic *** particular,the paper discusses the equivalences between risk-averse controller and filter designs and saddle-point solutions of some corresponding risk-neutral stochastic differential games with different information structures for the *** of the by-products of these analyses is that risk-averse controllers and filters(or estimators)for control and signal-measurement models are robust,through stochastic dissipation inequalities,to unmodeled perturbations in controlled system dynamics as well as signal and the measurement *** paper also discusses equivalences between risk-sensitive stochastic zero-sum differential games and some corresponding risk-neutral three-player stochastic zero-sum differential games,as well as robustness issues in stochastic nonzero-sum differential games with finite and infinite populations of players,with the latter belonging to the domain of mean-field games.

关键词： Mean-field games risk-sensitive control risk-sensitive filtering risk-sensitive games risk sensitivity robustness

Increasing spatial coverage in rough terrain and vegetated areas using InSAR optimized pixel selection:application to Tohoku,Japan

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Geo-Spatial Information Science 2022年第2期25卷 295-311页

作者： tamer ElGharbawi Masayuki Tamura Civil and Earth Resources Engineering Department Kyoto UniversityKyotoJapan

One of the major limitations of using Interferometric Synthetic Aperture Radar(InSAR)in time series analysis is the low-phase coherence associated with rough terrain and vegetated areas,which results in limited spatial coverage in such *** scatterers technique was introduced to overcome this limitation using time-series ***,identifying major scatterers within a pixel requires the single-looked pixels oversampling which can be a demanding process especially with large interferometric stacks and vast study ***,using multilooked temporal coherent pixels was proposed to increase processing efficiency and coverage by utilizing distributed targets,but this technique may exclude pixels with reliable phase returns because of their temporal varying neighboring *** this paper,we propose a technique to identify multilooked temporal stable pixels with reliable phase returns independent of their neighboring *** conduct a simulation analysis to relate the spatial coherence of a pixel with its expected temporal correlation in the time series analysis *** found that a liberal temporal correlation threshold of 0.53 in multilooked pixels stack is equivalent to a spatial coherence threshold of 0.2 when using number of looks of 9,which is considered acceptable in temporal coherent pixels,in terms of phase standard *** these findings to study the 2011 Tohoku earthquake in the northeastern part of Japan resulted in increasing the number of usable pixels and spatial coverage index by nearly 50.4%and 36.8%,respectively,compared to the temporal coherent ***,we propose an approach to integrate GPS observations with InSAR time series analysis,which resulted in deformation maps of the megathrust 2011 Tohoku earthquake with mean RMSE of 11.4 mm and a correlation of 98%in comparison to GPS observations.

关键词： 2011 Tohoku earthquake temporal stable pixels coherence phase noise GPS coverage index

A survey of RDF data management systems

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Frontiers of Computer Science 2016年第3期10卷 418-432页

作者： M. tamer OZSU Cheriton School of Computer Science University of Waterloo Waterloo N2L 3G1 Canada

RDF is increasingly being used to encode data for the semantic web and data exchange. There have been a large number of works that address RDF data manage- ment following different approaches. In this paper we pro- vide an overview of these works. This review considers cen- tralized solutions （what are referred to as warehousing ap- proaches）, distributed solutions, and the techniques that have been developed for querying linked data. In each category, further classifications are provided that would assist readers in understanding the identifying characteristics of different approaches.

关键词： RDF SPARQL linked object data.

Communication Scheduling and Remote Estimation With Adversarial Intervention

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IEEE/CAA Journal of Automatica Sinica 2019年第1期6卷 32-44页

作者： Xiaobin Gao Emrah Akyol tamer Basar the Coordinated Science Laboratory University of Illinois at Urbana-Champaign IEEE the Electrical and Computer Engineering Department The State University of New York at Binghamton

We study a communication scheduling and remote estimation problem within a worst-case scenario that involves a strategic adversary. Specially, a remote sensing system consisting of a sensor, an encoder and a decoder is configured to observe,transmit, and recover a discrete time stochastic process. At each time step, the sensor makes an observation on the state variable of the stochastic process. The sensor is constrained by the number of transmissions over the time horizon, and thus it needs to decide whether to transmit its observation or not after making each measurement. If the sensor decides to transmit,it sends the observation to the encoder, who then encodes and transmits the observation to the decoder. Otherwise, the sensor and the encoder maintain silence. The decoder is required to generate a real-time estimate on the state variable. The sensor,the encoder, and the decoder collaborate to minimize the sum of the communication cost for the sensor, the encoding cost for the encoder, and the estimation error for the decoder. There is also a jammer interfering with the communication between the encoder and the decoder, by injecting an additive channel noise to the communication channel. The jammer is charged for the jamming power and is rewarded for the estimation error generated by the decoder, and it aims to minimize its net cost. We consider a feedback Stackelberg game with the sensor, the encoder, and the decoder as the composite leader, and the jammer as the follower. Under some technical assumptions, we obtain a feedback Stackelberg solution, which is threshold based for the scheduler,and piecewise affine for the encoder and the decoder. We also generate numerical results to demonstrate the performance of the remote sensing system under the feedback Stackelberg solution.

关键词： Cyber physical security estimation game theory sensor networks