Proof & Experimental Establishment

This paper presents the design and analysis of isolation improvement for Fixed Head Doppler Radar Applications. Transmitting and receiving antenna of $4 \times 8$ microstrip patch antenna array has been designed by using RT/Duroid-5880 $\left(\varepsilon_{\mathrm{r}}=2.2\right)$ as a substrate. A novel metal slab isolator is proposed to reduce the mutual coupling between Transmitter and Receiver of two S-Band large Antenna Arrays. The obtained results show the maximum isolation of -92.39 dB and the improvement of 61 dB in isolation level by using metal slab having height of 40 mm and width of 20 mm between transmitting and receiving antenna of radar. The proposed structure is compared with the reported literature and the improved isolation is attained with the metal slab isolator.

Surveying is used to determine impact point in an artillery test range. Triangulation is a suitable means of measuring the impact point coordinates without physically visiting the area. The parameters derived from the measurements are Mean Point of Impact (MPI) and Probable Error (PE). It is essential to understand the statistical distribution of the parameters and behavior of the key statistics of the parameters and their dependency on the measurement setup in a test range scenario. This paper explores the above statistics using numerical methods which is otherwise impossible to obtain experimentally from a limited number of trials. The use of Monte Carlo method has been demonstrated for the given analysis.

BackgroundNoise pollution poses a significant public health risk, with prolonged exposure to high levels of noise linked to various adverse outcomes such as annoyance, sleep disturbances, cognitive impairment, hypertension, and cardiovascular diseases. Noise-induced hearing loss (NIHL) is a prominent concern in noisy occupational settings.MethodThis study investigated NIHL among 621 male Air Force soldiers aged 18-45, exposed to intense aircraft noise. Auditory assessments included pure-tone audiometry (125 Hz to 8 kHz) to categorize hearing into normal, mild, moderate, and severe impairment. Distortion product otoacoustic emissions (DPOAE) and auditory brainstem response (ABR) were used to evaluate cochlear and auditory nerve function. Heart rate variability (HRV) provided insights into autonomic responses. Cognitive functions were assessed through computerized tests, and blood plasma was analyzed for cardiac biomarkers, oxidative stress indicators, inflammatory markers, and neurotransmitters. Proteomic analysis used iTRAQ labeling, MudPIT, and MALDI-TOF/TOF mass spectrometry for protein quantification and identification, with validation through ELISA.ResultsThe audiometric tests revealed varying degrees of hearing impairment, with significant threshold differences at 2000, 3000, 4000, and 6000 Hz, especially pronounced at 6000 Hz. The right ear showed greater impairment, and a characteristic high-frequency notch was observed, consistent with noise exposure. Proteomic analysis indicated that NIHL is associated with oxidative stress and systemic inflammation, with differential protein expression related to hearing, coagulation, and inflammation.ConclusionThis study highlights the severe impact of aircraft noise on hearing and systemic health, demonstrating correlations between hearing impairment and biochemical markers. It emphasizes the role of oxidative stress and inflammation in NIHL development and underscores the need for effective noise management and protective measures in noisy work environments.

This paper studies the dynamic and elevated temperature behavior of rolled homogeneous armor steel, which is crucial for applications such as blast, impact, crash, and ballistic resistance. The deformation behavior is analyzed through tensile tests. The tensile tests of RHA steel are conducted at quasi-static 10−4s−1≤εṗ≤10−1s−1 to dynamic 10−1s−1≤εṗ≤36.439s−1 strain-rates and at high temperatures ranging from room temperature (RT,27°C) to 500°C. Phenomenological Johnson-Cook (JC) models and semi-physical Rusinek-Klepaczko (RK) material models are employed in finite element (FE) simulations of tensile tests. The JC failure model, with a small modification, is used along with the material models to simulate the loss of load-bearing capacity of the component. All necessary material parameters are extracted from the test data. The material models and the damage model are integrated into ABAQUS CAE FE software through a user-defined material subroutine (UMAT). The simulated outcomes acquired from diverse material models are validated with relevant experimental findings, and the effectiveness of each material model is evaluated through qualitative and quantitative assessments. Observations reveal limitations in the existing models to accurately replicate material behavior under tension, particularly in the dynamic strain rate, and elevated temperature range. Consequently, a modified version of the JC model (MJC) is explored to better account for the impact of temperature on strain hardening and strain rate hardening. The proposed modification in the material model significantly enhances the predictive accuracy of FE simulations of tensile deformation across the entire spectrum of studied strain rates and temperatures compared to the original JC and RK models.

Confidentiality of data remains vital for securing critical knowledge and secure communication of information. One possible method of secure communication is encryption where data is obscured in such a format that makes little sense. The other method is steganography where information is hidden within a cover medium so as to remain undiscoverable and hence secured. Data hiding techniques are as old as the civilization itself and research is still going on to develop improved steganographic methods that can securely hide confidential data within different cover media. Digital images being easily available and offering a high level of redundancy, are considered as popular cover media. However, in this age of high-speed Internet, audio is not only abundantly available but is also heavily shared between various peers. It is also part of the video files. Therefore, audio can be a good cover for hiding text, images, audio, or video data. In this paper, we have suggested a novel audio steganography model that securely hides a high volume of data. The method is proved to be robust against various statistical and cryptanalytic attacks.

Management of Municipal Solid wastes (MSW) is a genuine problem to all Municipal Corporations irrespective to their size, population or financial condition in India. Scientific technologies are available for pollution free hygienic disposal of all biodegradable solid wastes by converting them to good quality compost and also for systematic recycling of non-biodegradable wastes for their beneficial utilization. Machineries are also available for converting Municipal solid wastes to energy for partial fulfillment of highly demanded electricity. But still all Municipal Corporation in India mainly depend on old open dumping of solid wastes in some low lying dump-yards creating known environmental pollution hazards. The Municipal authority, the district administration and the common citizens have to play a constructive role for overcoming this problem. Important challenges faced by Municipal authorities all over India are non-preparedness to handle huge quantity of MSW generated daily, lacking of awareness by common people on benefits of segregation of MSW at source, non-availability of infrastructure as well as expert / skilled manpower for scientific disposal of MSW, accurate forecasting about city wise MSW generation and proper encouragement to Public – private partnership (PPP) model for efficient management of MSW. Everyone is essential part of this management system. Citizens have to take the responsibility for segregating solid wastes at home before handing over to Municipal workers and for refraining themselves from throwing out any solid wastes. Municipal corporations have to consider MSW as important resource material, use it for beneficial purposes through vermicomposting and recycling, and to stop dumping of MSW at outskirt by unnecessary spending money on its transportation. It is mainly found that installation of costly machinery for mechanical composting and electricity generation have sometimes become not 2 much fruitful to Municipal authorities due to lack of their expertise as well as maintenance and repairing problem of machineries. Scientific disposal with the help of NGOs and Entrepreneurs are found more effective, employment generative and cheaper than adopting costly mechanical system. Paradigm shift in thought process of every citizen can change the situation of management of municipal solid waste successfully.

In the present study, the drag variation and trajectory elements estimation of a supersonic projectile having two different nose shapes are made numerically. The study aims at finding the coefficient of drag and shock wave pattern for 130 mm artillery shell fitted with recovery plug or with fuze, when travelling at zero angle of attack in a supersonic flow of air. The coefficient of drag (CD) obtained from the simulation is used as an input parameter for estimation of trajectory elements. The numerical results, i.e., the coefficient of drag at different Mach numbers and trajectory elements are validated with the data recorded by tracking radar from an experimental firing. Based on numerical results and data recorded in experimental firing, the coefficient of drag in the case of the shell with recovery plug is 2.7 times more than for the shell with fuze. The shock wave in the case of the shell with recovery plug is detached bow shock wave, whereas in the case of a shell with fuze, the shock is attached. The results indicate that the coefficient of drag increases with detached shock wave and an increase in the radius of the shell nose. Good agreements were observed between numerical results and experimental observations. Defence Science Journal, Vol. 64, No. 6, November 2014, pp.502-508, DOI:http://dx.doi.org/10.14429/dsj.64.8110

Proof & Experimental Establishment (PXE) is the premier DRDO Artillery Firing Range located along east coast of Odisha, covering 50kms along coast and around 40kms into area with various Range Infrastructure built around 3 Firing Points to conduct Artillery weapon firing for fulfilling services requirement and R&D developmental activity. Ordnance factories, Public sector units and sister DRDO laboratories are primary users of this Firing Range. DGQA sentences the production lots based on results compiled by PXE. In order to fulfill the production target as well as various other DRDO, OFand PSU’s development trials, dedicated scientific and service community of PXE play untiring role by meticulously planning, executing various trials successfully. This special issue of Defence Science Journal on of futuristics development in Test & Evaluation of armamentscovers in total 9 technical papers that highlight primarily PXE R&D activity/developmental task for fulfilling dynamic evaluation of present and future Artillery Weapons. Defence Science Journal, Vol. 64, No. 6, November 2014, pp.497, DOI:http://dx.doi.org/10.14429/dsj.64.8107

Automated detection of changes in a sequence of images captured under fixed background and steady light condition is an often required operation having widespread application. Possible application areas can be as diverse as from military to atmospheric science, from medicine to video surveillance, etc. There are many approaches to the problem of detecting changes; the more reliable one tries to make these more complex and computationally expensive these become, requiring sophisticated algorithms and specialised hardware. However, often one needs to use simple and computationally cheap procedures to be used with cots hardware when the problem scenario has static features with transient change in features associated to some small part of the image or field of view. A super-pixel-based change detection algorithm has been descried here that is basically a modification of the image differencing technique. The procedure has been seen to detect even a small transient change in intensity at a frame rate of as high as fifty frames per second using cots hardware. Defence Science Journal, 2011, 61(1), pp.51-56 , DOI:http://dx.doi.org/10.14429/dsj.61.479