Defence Science Journal
Not a member yet
3794 research outputs found
Sort by
Human and Environmental Bias Affecting Risk Perception in Military Radiological and Nuclear Operations
Get PDFThe urban military operating environment may offer favorable conditions for combat involving asymmetric actions or 4th generation warfare which includes the chemical, biological, radiological, or nuclear (CBRN) environment. The CBRN environment is characterized by threats and hazards capable of producing negative impacts to the operations. The detriment may be produced by intentional release of hazardous materials into the operational environment. This study deals with an environment deliberately contaminated by radioactive materials because of the activation of a radiological dispersive device (RDD). A computer simulation of the radioactive scenario was performed in order to produce useful information which in turn can be used to support decision-making. The main goal was to assess the risk of developing radio-induced solid cancer by studying the articulation between local environmental variables and a cognitive bias, the Dunning-Kruger effect. The findings highlight intuitive correlations between local atmospheric stability and cognitive bias affecting the threat level (radiation dose), the responsiveness and the perceived risk. The findings also allow us to infer that, especially in the military-operational context, the methodology proposed for the assessment of environment-human interactions may be decisive for correctly direct available resources, both human and material, reducing operational risk
RCS Modeling and Validation of Full Scale Launch Vehicle for its Real Time Dynamic Trajectory
Get PDFRadar Cross Section (RCS) plays a significant role in detecting and tracking the space-based objects such as launch vehicles, missiles, aircrafts etc. In space applications, Radar systems are used to track and provide real-time trajectory information of the satellite launch vehicles after the lift off from the launch pad for range safety purpose. RCS is a critical key parameter that determines tracking performance of the Radar and it is highly dependent on both Radar operating parameters and the target characteristics. For space-based applications, a good quantity of RCS is required for quick detection by the Radar for continuous tracking. In order to choose the best Radar tracking configuration for real time tracking of the launch vehicle, it is required to model and simulate the launch vehicle’s RCS fluctuations prior to launch in order to predict the real time Signal to Noise Ratio (SNR) for its complete dynamic trajectory. This modeling and simulation methodology will help to choose the optimum Radar configuration for obtaining a good quantity SNR in the real-time launch. This study also provides good guidance to Radar operators for the effective Radar operation during real time space object tracking. This paper demonstrates, the real-time RCS fluctuations of a typical ISRO launch vehicle through simulation for its dynamic trajectory using physical optics based EM software prior to launch. Furthermore, the simulation results are validated with real time monostatic Radar tracking data, which showed good agreement
Bounded PCA based Multi Sensor Image Fusion Employing Curvelet Transform Coefficients
Get PDFThe fusion of thermal and visible images acts as an important device for target detection. The quality of the spectral content of the fused image improves with wavelet-based image fusion. However, compared to PCA-based fusion, most wavelet-based methods provide results with a lower spatial resolution. The outcome gets better when the two approaches are combined, but they may still be refined. Compared to wavelets, the curvelet transforms more accurately depict the edges in the image. Enhancing the edges is a smart way to improve spatial resolution and the edges are crucial for interpreting the images. The fusion technique that utilizes curvelets enables the provision of additional data in both spectral and spatial areas concurrently. In this paper, we employ an amalgamation of Curvelet Transform and a Bounded PCA (CTBPCA) method to fuse thermal and visible images. To evidence the enhanced efficiency of our proposed technique, multiple evaluation metrics and comparisons with existing image merging methods are employed. Our approach outperforms others in both qualitative and quantitative analysis, except for runtime performance. Future Enhancement-The study will be based on using the fused image for target recognition. Future work should also focus on this method’s continued improvement and optimization for real-time video processing
A Novel Scheme of an Optimal Data Rate Transmission for Airborne Telemetry of Long Range Aerospace Vehicle
Get PDFAirborne telemetry data is inevitable during the development phase of an aerospace vehicle. With the availability of telemetry data the vehicle characteristics are evaluated and the vehicle objectives are achieved subsequently. During the trajectory path, the airborne telemetry system transmits vehicle data continuously and ground receiving station receives it. The availability of data at ground station is solely dependent on various parameters; primarily data rate, modulation, RF power, etc. In this paper, typical data rate of telemetry for long range aerospace vehicle is analyzed and an innovative scheme is proposed for optimal data rate transmission with multi-resolution of high speed image data for distributed telemetry system. The scheme is implemented on 25 nm ZYNQ CSOC of telemetry hardware and synthesized netlist is simulated, performance is evaluated and results verified on telemetry hardware
Materials and Coatings for Defence Application
Get PDFResearch activities on materials and coating for defense applications sky the limit. The idea for special issue on‘Materials and Coatings for Defense Application’ nucleated quite some time back keeping in mind the direction of future research. However, it took its own time to translate it to actual fact. The purpose of this special issue is to bring out the recent development and progress in research activities in DMRL with regard to defense applications, introduce new comers to this area and foster interdisciplinary research among various communities working in this area. The special issue contains 15 manuscripts composed by various groups in Defence Metallurgical Research Laboratory
Investigation of Hazardous Materials in Firecrackers using LIBS Coupled with a Chemometric Method and FTIR Spectroscopy
Get PDFThis article reports the detection and quantification of toxic constituents in firecrackers using LIBS coupled with PCA and FTIR. Spectral signatures of lethal elements along with other elements and electronic bands of Cyanide, AlO, BaO, and CaO are seen in their LIBS spectra which confirms the presence of inorganic and organic compound in the fireworks. The concentration of each constituent/element is determined using the CF-LIBS method and results are compared with ICP-OES results. The concentration of Al is in adequate amount except S4 (b). Li and Ba are present in all samples with maximum amount in S4 (b) and S3 respectively. Molecular stretching of SO4-, C4 H8 - , CuCl- , CO3 - , and NO3 - are observed in the FTIR spectra of the samples. The combined results of LIBS and FTIR recommends the presence of BaNO3 , LiCO3 , SrCO3 , Al-chip, and charcoal in the firecrackers. To discriminate various firecrackers, PCA of the LIBS data is performed. The results show that S3 and S4 (b) are more harmful as they contain higher concentration the compounds of Al, Ba, Li, Sr i.e BaNO3 , LiCO3 , SrCO3 , (Cu3 As2 O3 Cu(C2 H3 O2 )2 )
Rocket Sled Based High Speed Rail Track Test Facilities
Get PDFThe present study introduces and compares several high-speed track based ground test facilities available all over the world to simulate high-speed dynamic events for selected portions of flight trajectories. The scope of performing high speed flight-testing is addressed, which is followed by the requirements of these track based test facilities. The facilities deliver flight test articles under controlled conditions to achieve high velocity impact, acceleration, aerodynamic and other related testing for small and large test articles depending upon the requirements. Sled is designed in such a way so that it can carry the test articles like aircrafts, payloads, warheads, missiles and many other ballistic systems to achieve high velocities ranging from subsonic to hypersonic by accelerating these sleds using solid rocket motors over the rail track. Such facilities provide instrumentation for large set of trial data acquisition and offline analysis for both recovery and non- recovery (impact) trials, which makes such facilities important for test, research and evaluation purposes.
Here, the detailed description of test facilities, which are available in many countries such as India, United States (US), Japan, United Kingdom (UK), France, and others countries based on their technical characteristics is presented. Additionally, a brief history and introduction into basic rocket sled test facility aspects, essential technical characteristics and major features to support high speed testing at these facilities as an accurate testing technique based on quality of construction and engineering design are also covered in this paper. Compilation of available or under development facilities is done in one place which provides the information about facilities’ technological gaps. The paper concludes with an explanation of the role, major capabilities and limitations of these test facilities in the present global scenario
Experimental Analysis of Viscoelastic Properties of Room Temperature Vulcanized Silicone based Magnetorheological Elastomer
Get PDFMagnetorheological Elastomers (MRE) endure a change in mechanical properties with the application of an externally applied magnetic field. It consists of an elastomeric matrix reinforced with ferromagnetic powdered particles. This paper focuses on the investigation of viscoelastic properties of Room Temperature Vulcanized (RTV) silicone based isotropic MRE in sandwich beam configuration by varying the volume percentage of Carbonyl Iron Powdered (CIP) reinforcement. Viscoelastic properties of the MRE core material were calculated by following the ASTM E756-05 standard. The magnetic field was applied by employing a Halbach array which was numerically analyzed using Finite Element Method Magnetics (FEMM). The magnetic field was varied up to 0.15 T. Loss factor and shear modulus were found to be strongly influenced by the percentage content of CIP. The loss factor and shear modulus of 30% MRE at 0.15 T were higher than other tested samples. The variation of natural frequency with respect to the addition of CIP was validated numerically using Modal analysis conducted in Hyperworks
Obscurant and Radiation Characteristics of Infrared Screening Smoke Composition Based on Red Phosphorus
Get PDFRed phosphorus-based camouflage compositions are often used on naval ships to counter anti-ship missiles. This work focused on investigating the obscurant and infrared radiation characteristics of infrared-screening smoke of pyrotechnic compositions based on red phosphorus, Mg-Al alloy, barium nitrate and Viton A rubber. The results demonstrated that the smoke clouds of the formulation based on red phosphorus and Mg-Al alloy have a high attenuation capability to 1.064 µm laser radiation. Besides, these smokescreens also have a better emission power in the wavelength range of 2.5-5 and 8-14 µm. Therefore, the smoke compositions based on red phosphorus and Mg-Al alloy can be used in camouflage devices on naval ships against infrared and laser-guided missiles
Camouflage Assessment of Aluminium Coated Textiles for Woodland and Desertland Combat Background in Visible and Infrared Spectrum under UV Vis IR Background Illumination
Get PDFAluminium powder (AP) formulated polyamide 6, 6 (PA 6, 6), cotton fabric and hollow tubular polyester beg (HTPB) were experimented for spectral, chromatic and imaging principle of woodland and desertland camouflage textiles in visible (Vis) and infrared (IR) spectrum under three-dimensional background illumination of ultraviolet (UV)-Vis-IR for concealment and detection of target signature, AP formulated fabric practiced by defense professional. Cotton and polyamide 6, 6 fabric, HTPB were coated and padded with AP powder formulated polyurethane (PU) based binder. Reflection profile of woodland combat background (CB) and coated-padded textiles have been depicted in terms of multidimensional illumination properties of Vis imaging such as chromatic intensity, spectral reflection, Kubelka-Munk (K-M) reflectance, color rendering and photonic response. A symmetrical chromatic value (L*, a*, b*) of AP coated fabric has been portrayed for concealment of target signature against woodland CB. Spectral reflection, chromatic illumination, K-M reflectance and scanning electron microscopy have also been critically confirmed five-time durability of color fastness to wash, tested by AATCC method 61-2013. HTPB-phase change material (PCM) formulation has been found temperature controllable effect of target object (TOB) in terms of heat energy at limited temperature, 30°C. Heat energy versus target concealment of IR imaging principle can be implemented for high-performance camouflage textiles design. The reflection profile of AP coated fabric can be applied for multidimensional camouflage coloration/patterning/HTPB-PCM based IR camouflage technology and direct applications of defence pavilion/tents/clothing against woodland/desertland CB. Therefore, the key phenomenon of this article has been focused on remote sensing properties of eucalyptus tree, scientific name, Eucalyptus Mannifera, a common CB of woodland and AP formulated fabric for defence application against woodland and desertland CB in terms of concealment of defence surveillance under consideration of laboratory and field trialling of woodland and desertland camouflage textiles assessment in Vis-IR spectrum. Therefore, a standardised methodology of camouflage textiles assessment for CDRI has been established under a new technique with conformist machine and technology which may be a new contribution to carry out further research and development for the fighting protection in combat environment under maintaining a standardized sequence from laboratory trialling to field experimentation in a limited timeframe of research