Computers in Air Defence

With man's mastery over the third dimension - the near atmosphere and space- it has become increasingly necessary to protect oneself not merely from attacks from land and the sea but, more importantly, from attacks from the air. This was recognised even during the World War II and a rudimentary air defence capability was sought to be established; by the manul (visual) surveillance and the anti-aircraft guns. The advent of radar signified a major advance in air defence technology and techniques. Rather than depend on visual observation and the hazards and limitations thereof, it became possible with radar to detect the presence of flying objects at much great distances. The PPI display of a conventional air-surveillance radar permits an operator to scan the sky for several hundreds of kilometers all around. Early radar-based air defence systems were dependent on human observation and decision making for detecting targets, identifying them, deciding on interception strategy and for recovering the interceptor after completion of his mission. This was feasible because, with a radar of between 200 to 400 kilometers and aircraft speeds in the range of 500 kilometers per hour, upto 30 minutes warning was available before the target was overhead

Spectrophotometric methods for the microdetermination of oxytetracycline and hostacycline

New, rapid and sensitive spectrophotometric methods have been developed for the determination of Oxytetracycline (OTC) and Hostacycline (HTC). The procedure is based on the observation that, OTC or HTC forms colored complexes with Zirconium (IV), the absorbance of which is proportional to the amount of tetracycline present. The variables affecting development of the color have been investigated and the conditions are optimized. Beer’s law is obeyed in the range 1.0-33.5 μg/ml for OTC and 4.0-40.0 μg/ml for HTC. The proposed methods can be employed for the analytical determination of Zirconium (IV). The corresponding Beer’s law ranges are 0.2-6.1 μg/ml with OTC and 0.5-7.3 μg/ml with HTC. Stoicheiometry of the complexes, regression parameters and relative standard deviation are reported for each of these determinations. The methods are successfully applied for the determination of OTC and HTC in pharmaceutical formulations and urine. Key words: Spectrophotometric determination, oxytetracycline, hostacycline, zirconium (IV)

3,​3-​dichloro-​1,​2-​diphenylcyclopropene (CPICl)​-​mediated synthesis of Nα-​protected amino acid azides and α-​ureidopeptides

Rapid synthesis of acid azides via in situ generation of acid chlorides using CPICl as chlorinating agent from the corresponding Nα -protected amino acids is described. Also the conversion of acid azides into ureidopeptides through the Curtius rearrangement under ultrasonication is delineated. The mildness of the protocol renders the acid-sensitive substrates to afford the corresponding amino acid azides and ureidopeptides in good yields. Diphenylcyclopropenone has also been recovered from the reaction mixture and reused

Diversity and Distribution of Pteridophytic flora of Punyagiri hill, Vizianagaram District, Andhra Pradesh, India

The present paper deals with the diversity and distribution of Pteridophytic flora in Punyagiri hill.  It is located 180 06’ 70",180 06’ 68",latitudes and 830 06’ 72",830 06’ 40" longitudes , 55 km away from Visakhapatnam. Quadrate method was adopted to calculate the IVI. Sampling was carried out with 0.5x0.5m2 quadrate; fifteen quadrate samples were taken in three seasons. A total no of 13 species belonging to 10 genera and 9 families were recorded. Maximum relative density was reported for Selaginella involvense (10.6) and Pteris vittata (8.4). Minimum relative density and relative frequency were reported in the species Nephrolepis cordifolia(5.5) and Pteris pellucida (6.3). The maximum IVI was reported in Selaginella involvens (30.2) fallowed by Pteris vittata (26.2), Adiantum lunulatum(25.4), Pleopeltis pallida (24.5) and minimum in Nephrolepis cordifolia (18.6). It is concluded that the population of Pteridophytes in this region is heterogeneous

Development of gastro retentive drug delivery system of cephalexin by using factorial design

The objective of this research work was to formulate and optimize the floating drug delivery system containing cephalexin using 23 factorial design. Floating tablets were prepared by direct compression method incorporating HPMC K4M, xanthan gum, guar gum, sodium bicarbonate and tartaric acid as gas generating agent. The influence of independent variables like, polymer: polymer ratio, polymer type and tartaric acid on floating lag time and cephalexin release profile were studied. The diffusion exponent (n) of Krosmeyer Peppas for optimized formulation was found to be 0.635 which indicates the mechanism of drug release was anomalous transport. Floating lag time of optimized formulation was 1.50 min and remained buoyant for 24 hrs. Optimized formulation was checked for stability at 40ºC / 75% RH which was found to be stable. Scanning electron microscopy study revealed gel formation. FT-IR studies revealed that there was no chemical interaction between cephalexin and other excipients

Determination of Activation Energy of Relaxation Events in Composite Solid Propellants by Dynamic Mechanical Analysis

The shelf life of a composite solid propellant is one of the critical aspects for the usage of solid propellants. To assess the ageing behavior of the composite solid propellant, the activation energy is a key parameter. The activation energy is determined by analysis of visco-elastic response of the composite solid propellant when subjected to sinusoidal excitation. In the present study, dynamic mechanical analyzer was used to characterize six different types of propellants based on hydroxyl terminated polybutadiene, aluminium, ammonium perchlorate cured with toluene diisocyanate having burning rates varying from 5 mm/s to 25 mm/s at 7000 kPa. Each propellant sample was given a multi-frequency strain of 0.01 percent at three discrete frequencies (3.5 Hz, 11 Hz, 35 Hz) in the temperature range -80 °C to + 80 °C. It was observed that all the propellants have shown two relaxation events (α- and β- transition) in the temperature range -80 °C to +80 °C. The α-transition was observed between -66 °C and -51 °C and β-transition between 7 °C and 44 °C for the propellants studied. The activation energy for both transitions was determined by Arrhenius plot from dynamic properties measured at different frequencies and also by time temperature superposition principle using Williams-Landel-Ferry and Arrhenius temperature dependence equations. The data reveal that the activation energy corresponding to α-transition varies from 90 kJ/mol to 125 kJ/mol for R-value between 0.7 to 0.9 while for β-transition the values are from 75 kJ/mol to 92 kJ/mol. The activation energy corresponding to β-transition may be used to predict the useful life of solid propellant.Defence Science Journal, 2014, 64(2), pp. 173-178. DOI: http://dx.doi.org/10.14429/dsj.64.381

Mycobacterium tuberculosis-Driven Targeted Recalibration of Macrophage Lipid Homeostasis Promotes the Foamy Phenotype

SummaryUpon infection, Mycobacterium tuberculosis (Mtb) metabolically alters the macrophage to create a niche that is ideally suited to its persistent lifestyle. Infected macrophages acquire a “foamy” phenotype characterized by the accumulation of lipid bodies (LBs), which serve as both a source of nutrients and a secure niche for the bacterium. While the functional significance of the foamy phenotype is appreciated, the biochemical pathways mediating this process are understudied. We found that Mtb induces the foamy phenotype via targeted manipulation of host cellular metabolism to divert the glycolytic pathway toward ketone body synthesis. This dysregulation enabled feedback activation of the anti-lipolytic G protein-coupled receptor GPR109A, leading to perturbations in lipid homeostasis and consequent accumulation of LBs in the macrophage. ESAT-6, a secreted Mtb virulence factor, mediates the enforcement of this feedback loop. Finally, we demonstrate that pharmacological targeting of pathways mediating this host-pathogen metabolic crosstalk provides a potential strategy for developing tuberculosis chemotherapy

Evaluation of Chemical Protective Clothing: A Comparative Study of Breakthrough Times with Sulphur Mustard and a Simulant, 1,3-Dichloropropane

Carbon-coated non-woven fabrics were evaluated against vesicant sulphur mustard and l,3-dichloropropane (DCP). Breakthrough times of these chemicals were compared andfitted in a linear equation. A correlation, better than 95 per cent was obtained. It is recommended that DCP be used in the valuation and quality control of fabric in the chemical protective clothing manufacturing industries to reduce the exposure and risks of handling lethal chemicals. However,-the clothing may be challenged with actual CW agents to determine their protective potentials, in the laboratory. Diffusion coefficients for DCP were also computed from the breakthrough data for carbon-coated fabric of different grades

Water Pumping Arrangement for Solar PV ImpartialUtilizing PMSM Drive

This paper assesses courses in which they can be made productive. The part of productivity principles in accomplishing this objective and the propriety of existing measures is assessed. With the constant diminishing of the expense of sun oriented cells, there is an expanding intrigue and needs in photovoltaic (PV) framework applications taking after way of life changes. Water pumping framework fueled by sun powered cell generators are a standout amongst the most imperative applications. The variance of sun oriented vitality on one hand and the need to improve accessible sun based vitality on the other, it is valuable to grow new effective and adaptable modes to control engines that entrain the pump. A vectorial control of a no concurrent engine sustained by a photovoltaic framework is proposed. This paper examines a photovoltaic-electro technician chain, made out of a PV generator, DC-AC converter, a vector controlled affectation engine and outward pump. The PV generator is compelled to work at its greatest force point by utilizing a fitting hunt calculation incorporated in the vector control. The enhancement is acknowledged without need to adding a DC-DC converter to the chain. The engine supply is likewise guaranteed in all separation conditions. Reproduction results demonstrate the viability and achievability of such a methodology. Results are displayed in view of MATLAB/SIMULINK. This report proposes another converter for photovoltaic water pumping without the utilization of substance stockpiling components, for example, batteries. The converter is intended to drive a PMSM Motor specifically from PV vitality. The utilization of PMSM Motor gives a superior answer for the business dc engine water pumping framewor

The Strength of Receptor Signaling Is Centrally Controlled through a Cooperative Loop between Ca2+ and an Oxidant Signal

SummaryActivation of cell-surface receptors stimulates generation of intracellular signals that, in turn, direct the cellular response. However, mechanisms that ensure combinatorial control of these signaling events are not well understood. We show here that the Ca2+ and reactive oxygen intermediates generated upon BCR activation rapidly engage in a cooperative interaction that acts in a feedback manner to amplify the early signal generated. This cooperativity acts by regulating the concentration of the oxidant produced. The latter exerts its influence through a pulsed inactivation of receptor-coupled phosphatases, where the amplitude of this pulse is determined by oxidant concentration. The extent of phosphatase inhibition, in turn, dictates what proportion of receptor-proximal kinases are activated and, as a result, the net strength of the initial signal. It is the strength of this initial signal that finally determines the eventual duration of BCR signaling and the rate of its transmission through downstream pathways