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Kumar G.,Defence Research and Development Organization DRDO
Journal of Cold Regions Engineering | Year: 2015

A continuous snow fence of 50% porosity, 130 m in length, and 4.0 m height was installed to overcome the snowdrift problems at Banihal Top (Jammu and Kashmir, India) in the Himalayan region. The avalanche sites, which affect the north and south Portals of the Jawahar Tunnel, have catchment areas near Banihal Top. The width of mountainous ridge at this site is about 60 m except within a central depression area where the width is about 200-250 m. Snow mass is eroded from the southern windward slope and deposited on the northern leeward slope toward the Kashmir valley during the winter. The rates of erosion and deposition of snow are controlled by snow characteristics, the snow surface roughness, terrain features, and the snow fence configuration. The snow at Banihal Top is wet in nature and snow deposition due to snow drifting is found to be about 105 m3 per running meter of snow fence having a height of 4.0 m. The storage capacity of this snow fence is higher than that of previously installed snow fences of 3.0 and 3.5 m heights. The extension of deposited snow on the leeward side of the snow fence is found to be 15-17 times the snow fence height; this is comparatively smaller than the extension of drifted snow mass reported in Western countries. It is observed that the nose of the drifted snow profile is shifted toward the snow fence with a reduction of the snow fence porosity due to snow riming. Change in porosity due to snow riming of the fence reduces its capacity but it serves to accumulate more snow if the riming happened after the aerodynamic equilibrium state is reached. The snow fence has reduced the snow mass accumulation in the formation zone of the avalanche site. It has also helped to prevent blockage of the national highway NH-1 A and the North Portal of the Jawahar Tunnel in Jammu and Kashmir, India. © 2014 American Society of Civil Engineers.

Varun M.,St Johns College | D'Souza R.,St Johns College | Kumar D.,Defence Research and Development Organization DRDO | Paul M.S.,St Johns College
Environmental Monitoring and Assessment | Year: 2011

Toxicity of lead in soil is well documented and established. Phytoremediation has gained attention as a cheap, easily applicable, and eco-friendly clean-up technology. Chemical methods are used to assess exact levels and type of pollutants but heavy metal content in soil can also be evaluated indirectly by estimation of phytotoxicity levels using bioassays. Plant bioassays through fast germinating cereals can indicate not only the level of pollution and its effects on growth and survival but also the progress of phytoremediation process. The performance of barley Hordeum vulgare L. seedlings as bioassay for assessment of changes in the levels of lead (Pb) at three concentrations, i.e.; 300 (T1), 600 (T2), and 1,200 ppm (T3) in the soil was evaluated while testing the efficiency of Crinum asiaticum L. as a phytoremedial tool. At the first assessment, i.e.; 30 DAT (days after treatment) shoot and root lengths of seedlings decreased with increasing concentrations of Pb. As the study progressed, a decrease in levels of Pb was accompanied by better germinability and growth of barley. At 120 DAT seedling growth in all the treatments were comparable to control. In T 1, T2, and T3 soils, 74.5%, 83.7%, and 91.2% reduction in lead content was observed at 120 DAT. Highly significant correlations between decreasing pollutant (Pb) content in the soil, seed germination, and seedling growth of barley H. vulgare were found. The differences in root and shoot length as well as overall growth pattern are indicative of the suitability of barley as a bio-monitoring tool. © 2010 Springer Science+Business Media B.V.

Sundari S.M.,Defence Research and Development Organization DRDO
2013 International Conference on Control Communication and Computing, ICCC 2013 | Year: 2013

UAVs (Unmanned Aerial Vehicles) are essential elements in the military capabilities of every country. They are increasingly being used to carry out the high risk tasks of reconnaissance, surveillance and intelligence collection in combat situations and Target acquisition. Modern UAVs are used for many important application including Coastal surveillance, Disaster Management and news broadcasting. In India, among the various Defence Research and Development Organisations (DRDO), Aeronautical Development Establishment (ADE) is tasked with the development of indigenous UAV systems for armed forces. The various classes of ADE UAVs include tactical UAVs (Nishant), Aerial Target Systems (Lakshya), Medium Altitude Long Endurance (MALE) UAVs (RUSTOM). UAV system consists of a user friendly Ground Control Station (GCS) and the Unmanned Aerial Vehicle. The UAV incorporates a number of airborne processors to handle the communication, Flight control and navigation, as well as very reliable data links. © 2013 IEEE.

Agarwal P.,Defence Research and Development Organization DRDO | Jaysaval V.K.,Defence Research and Development Organization DRDO | Rajagopal S.,Defence Research and Development Organization DRDO
2014 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2014 | Year: 2014

Performance prediction of airborne radar is a challenging and cumbersome task in clutter scenario for different types of targets. A generalized model requires predicting the performance of Radar for air targets as well as ground moving targets. In this paper, we propose a generalized model to bring out the performance of airborne radar for different Pulsed Repetition Frequency (PRF) as well as different type of targets. The model provides a platform to bring out subsystem parameters for different applications and performance requirements under different types of clutter terrain. © 2014 IEEE.

Singh M.K.,Defence Research and Development Organization DRDO | Singh M.K.,Motilal Nehru National Institute of Technology | Gupta R.D.,Motilal Nehru National Institute of Technology | Snehmani,Defence Research and Development Organization DRDO | And 2 more authors.
Pure and Applied Geophysics | Year: 2016

Accuracy of the Digital Elevation Model (DEM) affects the accuracy of various geoscience and environmental modelling results. This study evaluates accuracies of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global DEM Version-2 (GDEM V2), the Shuttle Radar Topography Mission (SRTM) X-band DEM and the NRSC Cartosat-1 DEM V1 (CartoDEM). A high resolution (1 m) photogrammetric DEM (ADS80 DEM), having a high absolute accuracy [1.60 m linear error at 90 % confidence (LE90)], resampled at 30 m cell size was used as reference. The overall root mean square error (RMSE) in vertical accuracy was 23, 73, and 166 m and the LE90 was 36, 75, and 256 m for ASTER GDEM V2, SRTM X-band DEM and CartoDEM, respectively. A detailed error analysis was performed for individual as well as combinations of different classes of aspect, slope, land-cover and elevation zones for the study area. For the ASTER GDEM V2, forest areas with North facing slopes (0°–5°) in the 4th elevation zone (3773–4369 m) showed minimum LE90 of 0.99 m, and barren with East facing slopes (>60°) falling under the 2nd elevation zone (2581–3177 m) showed maximum LE90 of 166 m. For the SRTM DEM, pixels with South-East facing slopes of 0°–5° in the 4th elevation zone covered with forest showed least LE90 of 0.33 m and maximum LE90 of 521 m was observed in the barren area with North-East facing slope (>60°) in the 4th elevation zone. In case of the CartoDEM, the snow pixels in the 2nd elevation zone with South-East facing slopes of 5°–15° showed least LE90 of 0.71 m and maximum LE90 of 1266 m was observed for the snow pixels in the 3rd elevation zone (3177–3773 m) within the South facing slope of 45°–60°. These results can be highly useful for the researchers using DEM products in various modelling exercises. © 2015, Springer Basel.

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