Methodology to Measure the Protective Areal Density of Ceramic Tiles Against Projectile Impact

The protective areal density of any armour material is the important property required for armour design. In this study, ballistic performance of hot pressed boron carbide tiles, with a tile thickness of 12.2 mm, was evaluated using the protective areal density (PAD) test method, against hard steel 12.7 mm armour piercing (AP) projectiles. The binary response data on complete penetration/ partial penetration obtained from PAD testing was fitted with the standard logistic regression model. A detailed discussion on statistical procedure has been presented. The PAD (pp = 0.5) was estimated to be 82.5 kg/m2 and the lower and upper bounds of 95 per cent confidence interval for (PAD) (pp = 0.5) was found to lie between 79.5 kg/m2 and 85.0 kg/m2

Ballistic Performance of Alumina and Zirconia-toughened Alumina Against 7.62 Armour Piercing Projectile

A study was carried out to compare the ballistic performance of high purity alumina and zirconia-toughened alumina (ZTA) using depth of penetration (DoP) test configuration against 7.62 mm armour piercing (AP) ammunition. The effect of tile thickness on the differential efficiency factor (DEF) was studied for tile thickness in the range of 3 mm to 6 mm for alumina tiles and 3 mm to 5 mm for ZTA tiles. The DEF is found to increase as tile thickness increases. An analysis on the failed shots showed that the residual shot weight does not follow a single linear relationship with ceramic tile thickness unlike the residual DoP for all thicknesses of tiles. Post-ballistic analysis on ceramic powder for particle size distribution was carried out and the results are presented.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.477-483, DOI:http://dx.doi.org/10.14429/dsj.64.674

Effect of Boron Carbide on wear resistance of graphite containing Al7029 Based Hybrid Composites and its Dry Sliding Wear Characterization Through Experimental, Response Surface Method and ANOVA

Composites are often chosen for tribological applications due to its tailored material properties. The development of hybrid metal matrix composites and the study of their wear behavior has been a prominent focus of materials science research. Present paper deals with fabrication of Al-7029/B4C/Gr hybrid composite using stir casting. Particle distribution and material phase are identified by SEM and XRD. Hardness of the composite increased to 101 BHN while base alloy with 63 BHN. Pin-on-disc Tribometer used to carry wear test and the experimentation conducted by considering three input wear control parameters: 15–35 N (load), 1.5–3.5 m/s (speed) and 200–600 m (distance). Addition of 6%B4C/3%Gr, wear rate of hybrid composites reduced. ANOVA confirmed that load as the most influencing parameter on wear rate. RSM results correlates with mean effect plots of ANOVA and experiments and found that the results are in good compliance. SEM graphs of worn surface confirms that more wear occurred with increased load

Robot Acting on Moving Bodies (RAMBO): Interaction with tumbling objects

Interaction with tumbling objects will become more common as human activities in space expand. Attempting to interact with a large complex object translating and rotating in space, a human operator using only his visual and mental capacities may not be able to estimate the object motion, plan actions or control those actions. A robot system (RAMBO) equipped with a camera, which, given a sequence of simple tasks, can perform these tasks on a tumbling object, is being developed. RAMBO is given a complete geometric model of the object. A low level vision module extracts and groups characteristic features in images of the object. The positions of the object are determined in a sequence of images, and a motion estimate of the object is obtained. This motion estimate is used to plan trajectories of the robot tool to relative locations rearby the object sufficient for achieving the tasks. More specifically, low level vision uses parallel algorithms for image enhancement by symmetric nearest neighbor filtering, edge detection by local gradient operators, and corner extraction by sector filtering. The object pose estimation is a Hough transform method accumulating position hypotheses obtained by matching triples of image features (corners) to triples of model features. To maximize computing speed, the estimate of the position in space of a triple of features is obtained by decomposing its perspective view into a product of rotations and a scaled orthographic projection. This allows use of 2-D lookup tables at each stage of the decomposition. The position hypotheses for each possible match of model feature triples and image feature triples are calculated in parallel. Trajectory planning combines heuristic and dynamic programming techniques. Then trajectories are created using dynamic interpolations between initial and goal trajectories. All the parallel algorithms run on a Connection Machine CM-2 with 16K processors

WETTING AND DRYING RESISTANCE OF LIME-STABILIZED EXPANSIVE SOILS MODIFIED WITH NANO-ALUMINA

Weak soil at construction sites necessitates ground improvement. Chemical stabilization is typically carried out using either lime or cement. The primary objective of this study was to assess the strength and durability of lime-stabilized soils modified with nano-alumina (NA). This study adopted the scientifically established initial consumption of lime (ICL) content for soil stabilization. In addition, nano-alumina was added in varying percentages as an auxiliary additive. It was observed that 0.5 % of nano-alumina was optimal with respect to the ICL for maximizing the soil stabilization. The stabilized soils were cured for 0, 7, 14, and 28 days. Post-curing testing revealed that the strength increased sixfold for the optimal combination, compared with the virgin soil. To understand the durability behavior of the optimal combination, the stabilized soil specimens were subjected to wetting and drying cycles after 28 days of curing. The optimal combination was nearly as durable as that of the lime-stabilized soil subjected to five cycles of wetting and drying

Applications of Box-Behnken experimental design coupled with artificial neural networks for biosorption of low concentrations of cadmium using Spirulina (Arthrospira) spp.

The present study deals with the application of artificial intelligence techniques coupled with Box-Behnken (BB) design to model the process parameters for biosorption of cadmium using live Spirulina (Arthrospira) spp. as adsorbent in open race way pond with Zarrouk medium. The biomass concentration of Spirulina spp. decreased to half at 4 ppm Cd (II) after 8 days. Based on the LCt50 values, 3.69 ppm (8th day), Spirulina (Arthospira) maxima showed maximum tolerance. Considerable growth and bioaccumulation of Spirulina spp. is observed below 1 ppm and tolerant up to 3 ppm. The cadmium adsorption on Spirulina spp. showed good correlation (R2 = 0.99) when applied to Freundlich equation and data fit into pseudo second order kinetics. A four factorial, three blocks and three level Box-Behnken design with initial concentration (1 ppb to 5 ppb), biosorbant dosage (0.1 gdw to 0.2 gdw), agitation speed (12 rpm to 16 rpm) and pH (6 to 8) as independent variables and percentage adsorption as dependent variable were selected for study. The data were further processed using artificial neural network model and DIRECT algorithm for better optimization. The final Cd (II) concentration of 0.5 ppb was achieved with 1 ppb initialconcentration under optimal conditions. A continuous desorption process was also developed for removal of cadmium from Spirulina (Arthrospira) sp

Assessment of Economic Loss due to Use of Legal Codend Mesh in Multi-day Trawlers in Gujarat

The current trawling practices result in high exploitation of juveniles of all commercial and non-commercial species, in all maritime states of India (Najmudeen and Sathiadas, 2008). For example, the percentage of juveniles exploited by trawl can be as high as 20 to 60% in the case of seerfishes and groupers and as much as 12% in the case of squids (Mohamed et al., 2009a). In other words, there is substantial amount of growth overfishing taking place for all commercial stocks in the trawl fisheries of India. Growth overfishing occurs when too many small fish are harvested, usually because of excessive effort and poor selectivity of the gear (e.g. too small mesh sizes) and the fish are not given the time to grow to the size at which the maximum yield-per-recruit would be obtained from the stock. A reduction of fishing mortality on juveniles or their outright protection, would lead to an increase in yield as well as profits from the fishery

Manual on Entrepreneur-Ready Technologies of CMFRI

CMFRI presented five entrepreneur- ready technologies in the “Innovation 4 Industry Meet” organized by Zonal Technology Management Centre, Business Planning & Development Unit (ZTMCBPDU), South Zone, CIFT and National Fisheries Development Board held at Visakhapatnam on 8th September 2010 and in the ‘Rural Technology Mela’ organized by National Institute of rural Development at Hyderabad during 2nd to 5th February, 2011. A detailed presentation and exposition including prospective business proposals on the five technologies namely‘Green Mussel extract (GMe)’, ‘Varna (the marine ornamental fish feed)’, ‘Broodstock development, captive breeding and larval production of 17 species of marine ornamental fishes’, ‘Larval production of Cobia fish’ and ‘A device for breeding and culturing marine fish in open sea through cage farming’ were made in the meets. ‘Open sea cage farming in HDPE cage’ and ‘Low cost cage farming in GI cage’ were show-cased in the recently held ICAR-CII Industry Meet organized at NAAS Complex, New Delhi on 23rd May, 2011. The presentation and the exhibition in these meets got the attention of many prospective industrialists/ entrepreneurs which resulted in signing up of a few business proposals