bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance of advanced composite solid rocket propellants based on novel oxidizers
Authors: Abd-Elghany Mohamed , Elbeih Ahmed , Klapötke Thomas M. , Abdelhafiz Mahmoud 
Published: October 2019

Abstract
Three novel high energy dense oxidizers (HEDO), Bis(2,2,2-trinitroethyl)oxalate (BTNEOx), 2,2,2-Trinitroethyl-nitrocarbamate (TNENC), 2,2,2-Trinitroethyl-formate (TNEF) have been prepared and studied as oxidizers in composite solid rocket propellants (CSRPs). For comparison, traditional CSRP containing ammonium perchlorate (AP) bonded by hydroxyl-terminated polybutadiene (HTPB) binder system was studied. The optimum oxidizer percentage with respect to the specific impulse was determined using the thermodynamic code (EXPLO5_V6.03). In addition, the optimum oxidizer mixture based on the novel oxidizers with AP was studied. The combustion properties and gaseous products of the optimum propellant compositions were calculated. A selected composition was prepared in the lab. scale and the burning rate was measured by the strand burner method. It was concluded that TNEF based propellant possess the maximum specific impulse of all the studied compositions. In addition, TNEF based propellant has a higher burning rate than the traditional CSRP composition.
Impact and bending analysis of composite scarf adhesive joints modified with MWCNTs at room and hot temperatures
Authors: Khashaba U A , Othman Ramzi , Najjar I M R 
Published: October 2019

Abstract
Scarf adhesive joints (SAJs) have attracted an increasing attention in joining/repairing of carbon-fiber reinforced epoxy (CFRE) composite structures due to their zero eccentricity, which provides better aerodynamic surfaces. This study evaluated for the first time, the performance of SAJs in CFRE composites under thermo-mechanical impact loads. The adhesive was modified with optimum percentage of multi-walled carbon nanotubes (CNTs). The impact tests were performed at room temperature of +25°C, +50°C and +75°C. The residual flexural properties of the unfailed impacted joints were measured using three-point bending test. Results from impact tests at temperature of 25°C, 50°C and 75°C showed improvement in the impact bending stiffness of the modified SAJs with CNTs by 8.3%, 7.4% and 11.8% and maximum contact force by 15.6%, 21.3% and 18.9%, respectively. The energy at failure of the CNT-SAJs was increased by 15.2% and 16.4% respectively at temperatures of 25°C and 50°C. At test temperature of 75°C the SAJs have hysteresis load-displacement behavior and energy-time curve with rebound energy of 35% and absorbed (damage) energy of 65%. The residual flexural strength of the modified and unmodified SAJs is 98.2% and 86.1% respectively, while their residual moduli have remarkable decrease to 71.7% and 81.3%.
Harmonic mitigation for power rectifier using passive filter combination
Authors: Monem O A 
Published: October 2019

Abstract
Power rectifiers are widely used in different industrial applications that deliver DC voltage supply for many types of loads like electrolysis cells, metal electroplating and other DC loads. These rectifiers act as nonlinear loads injecting harmonic currents to the AC mains with lots of troubles and negative impact on the utility grid and the load itself, like increasing losses, measurement error, protection device false tripping and distortion of the voltage at the PCC affecting other loads at the same point. For this reason, many researches focus on this problem and how to mitigate it. In this research, power analysis measurements are taken for 750 KW power rectifier feeding electrolysis cells and define the power quality indices compared to IEC 519 Standard. Passive filter is selected to mitigate the recorded harmonics. Two types of filters are designed. The first is three single tuned passive filter to mitigate the 5th, 7th and the 11th harmonics. The second type is 2nd order high pass filter to mitigate harmonics equal and greater than 13th harmonics. MATLAB simulation is performed to validate the proposed solution. The current total harmonic distortion can be reduced from 29.6 % to 1.5 % and supply voltage total harmonic distortion is also improved from 3.25 % to 0.62% which meet the international standard and improve the power quality of the voltage at point of common coupling.
Ground target localization and recognition via descriptors fusion
Authors: Kamel Mohamed M , Taha Hussein S , Salama Gouda I , Elhalwagy Yehia Z 
Published: October 2019

Abstract
Keypoint matching can be defined as locating the position of a particular point in two images precisely. Recently, keypoint descriptors have taken a great effect targeting to be powerfully invariant to rotation, scale and translation for improving target detection. The detection task is carried out by a reference-scene image matching to localize the desired target in the input scene. An innovative approach is proposed in this work to fuse the state-of-the-art feature descriptors ORB, BRISK for the sake of accurate ground target detection in two phases. Firstly, off-line phase, where the fused features are extracted from different perspective, azimuth angles of the desired target to build a comprehensive reference image representation. Secondly, on-line phase, where the fused features extraction task is carried out from the whole scene. Hence, it is matched with the stored reference one to find the keypoints correspondence. The outliers’ problem is eliminated using Random Sample Consensus (RANSAC) algorithm resulting in speeding up the matching procedure. The conducted comparative analysis has revealed the discriminative power of the fused features in localization and recognition tasks while keeping the proposed system works in real-time.
Design of a roll autopilot for a skid-to-turn guided missile
Authors: Ali K M , Abozied M , Arafa I , Elhalwagy Y 
Published: October 2019

Abstract
the design of autonomous systems is a growing research field which attract an increasing interest in various civilian and military applications. The design of control system can be considered a leading factor for developing any autonomous system. In this paper devoted to a missile autopilot which should achieve specific characteristics and performance criteria to ensure the overall system stability to track the desired commands in the presence of high dynamics and different uncertainties with high accuracy. The investigation of accurate missile 6DOF model is developed and linearization has been performed for designing the proper controllers for the pitch and roll channels and choose the optimum trim points based on system dynamic pressure. A design of lead compensator classical controller is presented to meet certain requirement of both time and frequency characteristic to ensure the system stability. The designed autopilot is evaluated using Matlab simulation is carried out for evaluating the proposed missile autopilot controller performance, the proposed controller presented sufficient performance during flight and simplicity, reliability, and availability for implementation in real time applications.
Depolarization diagnosis of PWAS used for EMI based structural health monitoring system for composite plates
Authors: Amin Mostafa S , Salem Mohamed A M 
Published: October 2019

Abstract
Implementation of Electromechanical Impedance (EMI) as a technique to carry out Structural Health Monitoring (SHM) has been proved to be such effective tool in the last two decades, especially for structures made of composite material. EMI technique is the revolutionary evolution of the conventional Vibrational Based Damage Identification (VBDI) techniques. Unlike VBDI techniques, EMI technique has the privilege of employment tinny permanent piece of equipment which is known as Piezoelectric Wafer Active Sensor (PWAS). Although it has such advantage, it brings the necessity of continuous and robust diagnosis process of the PWAS used in the SHM system to ensure that output signals are caused by real variation of the modal parameters for the host structure rather than being occurred due to degradation and-or physical damage of the PWAS system itself. The study presented in this paper is focused on the self-diagnosis of PWAS used to carry out SHM via implementation of EMI technique. The main concern of this research is to study the ability of EMI technique to determine depolarization of PWAS and its influence on the performance of EMI based SHM system employed for structures made of composite plates. The used specimen (s) is / are underwent controlled excitation over desired frequency range, the imaginary part of admittance is plotted over desired frequency range. The whole process is then repeated for different levels of depolarization for the same specimen (s). The modeling process is carried out using a finite element commercial package, ANSYS v.15.0 in which multi-physics-based modeling can be used for such coupling field of piezoelectricity. MATLAB code is written to process the output data received from numerical simulations into counterpart spectrum and to calculate the statistical damage index Root Mean Square deviation (RMSD) that is used in damage detection. The calculated RMSD found to be non-zero values, which means false prediction. These results shows how important to have self-diagnosis for PAWS used in SHM system for further reliable measurements and data interrogation using EMI technique.
Design and implementation patch antenna with different fractal shape
Authors: Allam A. M. M. A. , Abo Sree Mohamed Fathy , Ibrahim Muhammad Aly 
Published: October 2019

Abstract
This work presents the effect of fractal shapes on the patch antenna. It is a conventional rectangular patch antenna with dimension of 9.2 mm × 6.94 mm. It is implemented on FR-4 lossy substrate material with relative permittivity of εr = 4.3, thickness of 1.6 mm and loss tangent of 0.025. It is feed through a microstrip line with dimension of 6 mm × 3.11 mm. The overall dimension of the antenna is 35 mm × 30 mm × 1.6 mm. It operates over a frequency band from 8 GHz to 12 GHz with central frequency 10 GHz. Application of Pythagorean tree Sierpinski gasket, and Koch curve is to decrease the bandwidth and increase the gain of the designed antenna. The performance properties of the antenna such as resonant frequency, radiation pattern, and gain were examined by simulation. The design is implemented through CST microwave studio and measured through network analyser.
Performance of LTE downlink communication system in presence of electronic warfare spot jamming
Authors: shabana Gamal H. , Shaheen Ehab M. 
Published: October 2019

Abstract
Wireless communication is one of the principally active zones of tools development and has become necessary part of everyday life. Simulation of wireless communication systems accurately is very important for predicting its performance under different scenarios. Long-Term Evolution (LTE) is named by next generation wireless communications. It is a standard for high-speed wireless communication for mobile phones and data terminals. In this paper, the performance of standard single-input-single-output (SISO) LTE Frequency Domain Duplex (FDD) downlink (DL) signal in additive white Gaussian noise (AWGN) channel is evaluated in two scenarios without jamming and in presence of electronic warfare spot jamming. Firstly, the performance of the standard LTE communication system in absence of jamming is investigated by calculating the probability of Bit Error Rate (BER) and Frame Error Rate (FER) versus Signal Noise Ratio (SNR). Secondly, the performance in presence of electronic warfare spot jamming scheme is investigated by constant Jamming to Signal Ratio (JSR) and different values of the normalized jamming bandwidth. In order to illustrate the impact of jamming on the standard LTE DL wireless communication system, the measurement is evaluated by using the aid of SystemVue software program.
Simulation and modelling of flight missile dynamics and autopilot analysis
Authors: Kamel Mohamed M , Ali Karim M , Abozied Mohammed A H , Elhalwagy Yehia Z 
Published: October 2019

Abstract
In the current paper, nonlinear modelling and dynamical analysis of a surface to surface missile with both aerodynamic and thrust vector control is investigated. Aerodynamic force and moment modelling of the presented missile includes the challenging high angle of attack aerodynamics behaviour and the so-called hybrid control, which utilizes both tail fins for stabilization and rudder vanes as control surfaces. Then, concerning relative rotation between bodies, the missile aerodynamic model is built by Leabedev aerodynamic calculations software. After using the generated aerodynamic data obtained the required aerodynamic stability derivatives, the required transfer functions are resolute based on the equations of motion of the missile. The missile dynamic motion in pitch and roll channel are analysed. The guidance and control strategy are developed through an actuation system and autopilot design in the four channels based on the poles assignment technique. The roll autopilot is constructed to regulate the roll angle of the front body of the missile which is the controlled part, for the command signals generated by the guidance laws both pitch and yaw autopilots are designed to realize. The guidance command is in the form of rate of change of flight path angles of the missile with time.
Implementation and validation of autopilot design for vertical missile systems
Authors: Ali K M , Abozied M , Arafa I , Elhalwagy Y 
Published: October 2019

Abstract
high nonlinearity and deficiency in control at boost-phase due to high angle of attack during maneuver and low velocity in the vertical launched missile. The necessity of high maneuverability and vertical launching require thrust vector control additional to aerodynamic control. effectively increasing the alertness of the missile against air defense threats by using That mixture usage of aerodynamic and thrust vector controls. Critical design of guidance and control is difficult and critical due to requirement and the rapidly changing dynamics of this type of missiles. The aim of this paper is to design autopilot with aerodynamics surfaces(fin)and thrust vector control by system characteristics reflection. by using Missile Lebadev Program (MLP) the model is developed based on the configuration of operating missile. Two control systems are aimed, which usages the command trajectory result optimization and the pitch rate controller which tracks real-time guidance command. The guidance and control strategy are developed through an actuation systems and autopilot design in the two channels pitch and roll based on the poles assignment technique. The investigation of the performance of pitch autopilot and its ability to reject disturbances due to cross-coupling between pitch and roll channels showed that, the pitch channel can reject disturbances within average time 3.5 sec.
Composite solid rocket propellant based on GAP polyurethane matrix with different plasticizers
Authors: Boshra Islam K. , Elbeih Ahmed , Mostafa Hosam E. 
Published: October 2019

Abstract
Glycidyl azide polymer (GAP) has been prepared and studied for its application as polymeric matrix for composite solid rocket propellants (CSRP). Different CSRP based on GAP polymeric matrix with different plasticizers were prepared. A cross-linker based on trimethylol propane (TMP) and dibutyltin dilaurate (DBTDL) was added to the GAP matrix to ensure curing completion of the prepared CSRP. The viscosity and shore A of all the prepared CSRPs during the curing process were measured continuously. The mechanical properties of the cured CSRP were determined. The ballistic performance, burning rate at operating pressure and specific impulse were determined using standard a modified six inch rocket motor with 16.25 mm nozzle. By comparing the results, it was concluded that the plasticizer; dioctyl azelate and dibutyl phthalate are not compatible with GAP matrix. In addition, CSRP based on GAP has specific impulse and burning rate slightly higher than the traditional HTPB based CSRP.
Involving PETN explosive into polyurethane polymer matrix for reactive armour applications
Authors: Elnogomy Mohamed , Elshenawy Tamer , Elbeih Ahmed , Radwan Mostafa , Yehia Mohamed , Baraka Ahmad , Elsayed Mohamed A. , Gobara Mohamed 
Published: October 2019

Abstract
This paper describes some formulations of plastic bonded explosives (PBXs) in the form of flexible material (sheet explosive) for military and civilian applications. Different compositions based on (70 wt%, 75 wt%, 78 wt%, 80 wt%) of PETN as high explosive filler were prepared by casting technique using HTPB polyurethane binder material. The production technique of the prepared explosive sheets was described in this research. Sensitivity to impact and friction were also measured. In addition, heat of combustion was determined. Besides, the detonation velocity was measured experimentally and the detonation characteristics were calculated using EXPLO 5 thermodynamic code. For comparison, standard commercial available plastic explosives such as EPX-1 and Datasheet C were studied. By comparing the obtained results, several relationships based on the results were observed. A good agreement between the measured and the calculated results was confirmed. Sample containing 78 wt% of PETN bonded by the polyurethane matrix is an optimum for the application of reactive armours.
Characteristics of a paste explosive (EPX-P20) used in explosive bolts for spacecraft’s applications
Authors: Elbeih Ahmed , Abdelhafiz Mahmoud , Hussein Ahmed K. , Wafy Tamer Z. , Elshenawy Tamer , Baraka Ahmad , Elsayed Mohamed A. , Gobara Mohamed 
Published: October 2019

Abstract
An explosive charge, located within a machined cavity in a bolt, provides the energetic stimulus required for cleanly bolt fracture. The shock wave produced fom the explosion causes tensile fracture along the bolt itself with minumum fragmentation and helps to control the separation process of the satellite from its rocket. In this study, EPX-P20 is a paste explosive in the research stage. EPX-P20 is based on PETN (pentaerythritol tetranitrate) bonded by polydimethyl-siloxane binder matrix. A computerizing mixer plastograph was used for the production of EPX-P20. The internal energy of combustion was measured and used to determine the enthalpy of formation. Sensitivity against both friction and impact stimuli were determined. The detonation properties were calculated theoretically using the EXPLO 5 soft code, while the detonation velocity was determined experimentally. For comparison, several commercial available explosives such as; Sprängdeg m/46, Formex P1, Semtex 10 and EPX-1 were investigated. It was proven that EPX-P20 possesses the lowest velocity of detonation while maintaining its very low sensitivity. Interesting inversely proportion relationship amongst the measured internal energy of combustion and the calculated heat of detonation was observed. The produced paste explosive might be used in explosive bolt for space craft’s applications.
Parametric study for reducing emission characteristics using different computational schemes
Authors: Kayed Hatem 
Published: October 2019

Abstract
The present study numerically predicts emissions (NOx & CO) characteristics issued from swirl burner using different computational schemes adopted in ANSYS 17.2. Various turbulence models were tested and compared in a structured grid having an average skewness of 0.04. RSM model shows the best results in predicting the central toroidal recirculation zone for such severe swirling flow (S>0.6). Three different schemes of combustion modeling were also tested and compared. Flamelet PDF model was preferred among other combustion models for its potential to consider non-equilibrium chemistry, where its choice was recommended form many studies in the literature. A radiation heat transfer analysis was carried out using P1 radiation model to account radiation effects in estimating NOx and CO concentrations. The effect of varying swirl ratio, excess air, diluting fuel with N2 and CO2, oxidizer preheating, and oxidizer composition on emissions (NOx and CO) reduction strategy concluded that increasing the swirl number, excess air factor, and (N2 and CO2) mixing ratios have a considerable influence on NOx and CO emissions reduction. While increasing the preheating temperature, and the oxidizer Oxygen concentration leads to an increase the NOx and CO emissions. Hence, a considerable reduction in NOx and CO formation was apparently observed by lowering the peak flame temperature less than 1800 K. These predicted outcomes are in agreement with measurements data published in the literature.
A road map to the detection performance of LFM-PC search radars with CFAR detectors
Authors: Abdel Latif Soliman Mohamed Samir 
Published: October 2019

Abstract
Pulse Compression (PC) radars are used to resolve the problem of designing long range radar systems with excellent range resolution. PC provides radar system with additional processing gain that enhances its detection capability. Among the different types of pulse compression waveforms, Linear Frequency Modulated (LFM) signals are the most tolerant to high Doppler shifts. This is why LFM-PC radars are widely utilized with high speed targets. However, the literature lacks a complete mathematical or simulation model to evaluate the its detection performance. This paper introduces a typical simulation model for search radar that is verified mathematically. The proposed model includes matched filter (MF), moving target detector (MTD), two different constant false alarm rate (CFAR) algorithms and LFM signal sidelobes on radar detection are to be considered. Two simulation models are introduced. Firstly, the Matlab simulation is introduced to verify the mathematical model and the theory. Secondly, the SystemVue simulation is applied to be used in the future work with the hardware in the loop facility.
Condition-based monitoring of a small centrifugal pump by vibration analysis
Authors: Abd-Elaal M , Lotfy M , Nabil T , Eldomiaty A 
Published: October 2019

Abstract
Rotating machinery vibration problem is the most significant restriction which control the life time and may cause disastrous failure of the entire system. The vibration monitoring is the main element for any customized maintenance program to guarantee power plant availability and minimize danger of predictable failures. The present work is an experimental study on a small centrifugal pump running in healthy and intentionally defected to show the difference in the vibration spectral and time domain. Triaxial acceleration measurements were made at the shaft of the pump. The most dangerous case of vibration denoted by the highest amplitude as determined as well as its corresponding frequency. The most serious case was the pedestal looseness with full flow rate which cause a vibration of amplitude of (0.104g) at frequency (47Hz). The unacceptable vibration, as classified according to ISO 10816 to have amplitude of (0.5g) for small machines within this rang of acceptable vibration it was not difficult to predict the artificial defects mode in the pump and demonstrated the capability of condition monitoring.