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 | Wind Dependence of L Band Radar Backscatter
Author : Kumar, Raj ;Bhaduri, Lakshmi;Sarkar, Abhijit
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 383-389
Subject : 621.38 Electronics
Keywords : SIR B ;SEASAT-SAR;SIR A;Empirical curve fitting;Surface wind speed;Microwave frequency band
Abstract : Like other microwave frequency bans, L-band scattering coefficient (neta/sup o/) measurements have shown a definite dependence on ocean surface wind speed (W). The relationship between the two depends on the observation angle of the radar. The satellite-borne L-band radars SEASAT-SAR and SIR-A made observations at fixed incidence angles, while the just completed SIR-B mission has made observations at multiple incidence angles. The present work uses the theory of scattering from a composite surface and generates an analytic function of neta/sup o/ - W relationship for varying incidence angle at L-band by the method of empirical curve fitting. |
| | Non-steady Force Measurement in an Orpheous Gas Turbine Engine Using Hydraulic Analogy
Author : Sandhu, P.P.S. ;Awasthy, K.L.;Rao, J.S.
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 391-400
Subject : 621.224 Turbines
Keywords : Fabrication of Turbine Blade ;Flat plates
Abstract : Determination of non-steady forces in a real turbine stage is difficult due to local flow conditions e.g. high pressure, high temperature and inaccessibility to the region etc. Experimentation in a real turbine is also prohibitive due to the costs involved. Recently, an alternative method of arriving at these non-steady forces through use of hydraulic analogy has been tried on flat plates. The paper describes the simulation of an orpheous gas turbine engine stage on the rotating water table. It discusses the modelling aspects and presents a comparison of the experimental and theoretical results obtained. |
| | A Computer Code For Evaluation of Design Parameters of Concrete Piercing Earth Shock Missile Warhead
Author : Ramarao, K. ;Roy, P.K.
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 401-409
Subject : 623 Military Science and Engineering
Keywords : CPESW ;Earth penetrating weapon system
Abstract : A simple and reliable computer code has been devised for evaluating various design parmeters, and predicting the penetration performance of concrete piercing earth shock missile-warhead and will be useful to the designers of earth penetrating weapon system. |
| | Tropospheric Scatter Propagation Measurements Beyond the Horizon in Arid Zone A Note
Author : Singh, M.D. ;Agrawala, S.N. ;Bhatnagar, P.S.
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 411-416
Subject : 551.51 Atmospheric Physics;551.5 Meteorology
Keywords : Troposcatter link ;C band ;Diurnal behaviour;Transmission loss
Abstract : Tropospheric scatter study beyond the horizon radio link presently necessitates tests to establish the median path loss and to determine the magnitude and duration of the path loss variations. The average basic transmission loss of the scattered component, L/sub bs/, can be found if K (ratio of r.m.s. value of scattered and constant component) and the resultant basic transmission loss L/sub bm/, are known. This paper also deals with the diurnal and seasonal behaviour of signal strength, based on the analysis of about ten months recording on a C band Troposcatter Link between Pilani and Delhi. |
| | A New Stability Concept for Propellants
Author : Gokhale, H.G. ;Singh, Harihar
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 417-423
Subject : 547 Organic Chemistry;54 Chemistry
Keywords : Reliability factor ;Chemical stability test;Nitric esters
Abstract : The chemical stability tests currently used for propellants suffer from some drawback. In this paper an attempt has been made to recast the existing system of stability testing in order to improve the reliability factor. A new stability concept has also been brought out based on the action of the stablizer and its derivatives with the decomposed products of the nitric esters, the chief constituents of the propellants. |
| | Comparative Study of Acetazolamide and Spironolactone on Regional Blood Distribution on Exposure to Acute Hypobaric Hypoxia
Author : Parshad, R. ;Divekar, H.M.;Singh, M.V.;Jain, S.C.
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 425-429
Subject : 61 Medical Sciences
Keywords : Oral treatment ;Radio iodinated serum albumin
Abstract : Regional blood distribution was studied in rats, which were divided into four groups viz., (i) control, (ii) exposed to acute hypobaric hypoxia, (iii) exposed to acute hypobaric hypoxia after oral treatment with 25 mg acetazolamide, and (iv) exposed to acute hypobaric hypoxia after oral treatment with 6 mg spironolactone. The regional blood distribution was measured using radio-iodinated serum albumin (R/sup 131/ISA). The acute hypoxic exposure results in major readjustment in the blood flow to the various organs mainly from the renal and splanchic vascular beds to the heart and brain. Treatment with acetazolamide and spironolactone results only in a slight decrease in blood contents of the heart, brain and lungs as compared to the hypoxia alone exposed group. |
| | Piezoelectric Properties of Solid Solution Ceramics A Note
Author : Biswas, A.B. ;Chincholkar, V.S.
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 431-433
Subject : 62 Engineering
Keywords : Morphotrophic boundaries ;Orthorohombic pahses
Abstract : Piezoelectric coupling coefficient for compositions in the quaternary system (BaPb) (NbZr)O/sub 3/ using Mason's technique are reported. It is found that the radial coupling coefficient is maximum for compositions at the morphotrophic boundaries in both tetragonal and orthorhombic phases of the system. |
| | Orthorohombic pahses ; Magneto Elastic Rayleigh Waves on the Surface of Orthotropic Cylinder of Varying Density
Author : Narain, Surya
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 435-442
Subject : 621.38 Electronics
Keywords : Axial waves ;Frequency equations;Three dimensional magneto elastic equations
Abstract : This paper studies magneto-elastic Rayleigh waves on the surface of orthotropic cylinder of varying density. Solving three dimensional magneto-elastic equations frequency equations for axial waves are derived. |
| | Nuclear Weapon and Military Equipment
Author : Natarajan, S.
Source : Defence Science Journal ; Vol:35(4) ; 1985 ; pp 443-450
Subject : 623 Military Science and Engineering
Keywords : Nuclear environment ;Hardened design ;Combat effective;Nuclear attack
Abstract : Military equipment must survive a nuclear attack if enough personnel required to operate them remain combat effective. To achieve this goal, the criteria that determine equipment survivability should be established and any new design should incorporate these criteria to evolve a hardened design. An analysis of the overall response by considering the response to each individual nuclear environment can result in a balanced overall hardened system. The paper discusses the criteria required to be known. |
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