 | Zero Dispersion Optical Fibres for High Data Rate Systems
Author : Rampal, V.V.
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 173-180
Subject : 621.39 Telecommunication
Keywords : Repeater spacing ;Single mode fibre
Abstract : The different dispersion parameters that contribute to the pulse spreading in a single mode fibre are discussed with particular reference to the possibility of reducing the total dispersion to zero and increasing the bandwidth and repeater spacing. |
| | Secondary Flow and Heat Transfer of Two Incompressible Immiscible Fluids Between Two Parallel Plates in a Rotating System
Author : Narayana, N. Venkata ;Rao, V.V.Ramana
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 181-198
Subject : 532 Fluid Mechanics
Keywords : Ratio of viscosities ;Secondary motion;Constant pressure gradients
Abstract : When a straight channel formed by two parallel plates, through which two immiscible fluids are flowing under constant pressure gradients is rotated about an axis perpendicular to the plates, secondary motion is set up. The secondary motion is analysed in detail for constant angular velocity ohm', lambda the ratio of their viscosities. The associated heat transfer problems, when the plate temperatures are equal and different, have also been studied. |
| | Effect of Ultrasonic Vibrations in Some Heat Treatments
Author : Suryanaryana, K. ;Sreekumar, K.;Vasudevan, R.
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 199-210
Subject : 669 Metallurgy
Keywords : Increased ductility ;Shorter process time;Spheroidisation;Porous compacts;Hardening of solid
Abstract : The effect of ultrasonic vibrations on many heat treatment processes, primarily ageing, and other such as, hardening of solid and porous compacts, spheroidisation, etc. are described. Results obtained with regard to ageing are particularly promising and indicate the possibility of obtaining a distinctly shorter process time as also an increased ductility at the same strength. These features may be of interest to the aircraft industry. |
| | Flow of a Dusty Gas Between Two Parallel Plates One Stationary and Other Oscillating
Author : Bhattacharyya, P. ;Mitra, P.
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 211-223
Subject : 532 Fluid Mechanics
Keywords : Velocities of dusty gas ;Mass concentration;Incompressible viscous dusty gas
Abstract : The solution for the flow of an incompressible viscous dusty gas, induced by two infinitely extended parallel plates when the lower plate is at rest and the upper plate begins to oscillate harmonically in its own plane, is obtained, It is found that (i) with the increase in the mass concentration both the velocities of the dusty gas and the particle decreases, (ii) the velocity of the dusty gas increases and that of the particle decreases with the increase in neta. |
| | Finite Bending of Blocks
Author : Rao, S. Ram ;Venkateswarlu, M.
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 225-230
Subject : 531 Mechanics
Keywords : Ellipsoidal shell ;Concentric hole;Circular block
Abstract : The problem of bending of a circular block with concentric hole into ellipsoidal shell is considered, and the earlier results have been obtained as particular cases. |
| | Couttete Flow of a Dusty Incompressible Fluid with One of the Horizontal Moving Boundaries Suddenly Stopped
Author : Ramacharyulu, N. Ch. Pattabhi ;Prasad, V.V. Ramana
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 231-240
Subject : 532 Fluid Mechanics
Keywords : Relaxation time ;Slip velocity;Skin friction;Flux;Impulsive motion;Dusty fluid
Abstract : The unsteady flow of an incompressible viscous fluid with a uniform distribution of dust particles between two parallel plates when one of which is impulsively stopped from the state of uniform motion is studied. Analytical expressions for velocities of the fluid and dust particles have been obtained. It is found that the dust particles slip on the wall which is brought to rest impulsively instead of sticking to it; on the other hand, they stick to the stationary plate. The slip-velocity of the dust is noticed to be decreasing as the physical time increases and the relaxation time of the dust particles decrease. |
| | Spectrophotometric Determination of Iron III after Separation by Adsorption of its N Benzoyl N Phenyl Hydroxylamine Complex on Napthalene
Author : Singh, H.B. ;Satake, Masatada
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 241-244
Subject : 54 Chemistry;547 Organic Chemistry
Keywords : Adsorption ;Ortho phenanthroline;BPA complex
Abstract : The novel method for the spectrophotometric determination of trace amount of iron (III) after separation of its BPA complex by adsorption on microcrystalline naphthalene is described. The epsilon/ sub max/ of the DMF solution of the adsorbate containing iron (III)- BPA complex at lambda/sub max/ 437 nm has been found to be 4.47 X 10/sup 3/. The effect of variables and interfering ions on the efficacy method has been studied. Sensitivity (in Sandell's notation) is 1.25 X 10/sup -2/ micro g of iron (III)/cm/sup 2/ and at a mean absorbance of 0.40000 is 1.25%. The method is useful for the analysis of standard reference materials and environmental samples. The results are comparable with those obtained using ortho phenanthroline. |
| | Viscous Liquid Layer Sandwiched Between Two Generalized Thermoelastic Halfspaces
Author : Harinath, K.S.
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 245-250
Subject : 532 Fluid Mechanics
Keywords : Liquid layer ;Effect of gravity
Abstract : A detailed investigation of waves in a viscous liquid layer of finite thickness sandwiched between two generalized thermoelastic halfspaces reveals the fact that for realistic situations one has to consider the effect of gravity at least in the liquid layer. |
| | Flow of an Oldroyd Fluid Past a Sphere at Low Reynolds Number
Author : Chaudhary, R.C. ;Verma, P.D.
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 251-254
Subject : 532 Fluid Mechanics
Keywords : Drag ;Newtonian fluid;Asymptotic technique
Abstract : Slow motion of an Oldroyd fluid past a sphere has been investigated using matched asymptotic technique. The drag experienced by the sphere has been obtained form the solution. To the first order in tau ( a non-Newtonian parameter), the drag is unchanged from its value for Newtonian fluid but to the second order the drag is decreased. |
| | Removal of Dissolved Salts and Toxic Substances from Water Using Desert Desalting Kit
Author : Gopal, Ram ;Das, Ghanshyam;Singh, Jeevan;Singh, Y.P.
Source : Defence Science Journal ; Vol:31(3) ; 1981 ; pp 255-259
Subject : 556 Hydrology
Keywords : Dissolved solids ;Brackish water;Exchange resin;Potable water
Abstract : A portable desert desalting kit for converting natural brackish water or waters deliberately contaminated with certain toxic substances into potable water has been developed. The potable water is of acceptable standards laid down by WHO/ICMR. Based on ion exchange resin, the kit consists of desalting bag with filter and eight chemical packets. It requires 15 min to obtain potable water (450 ml from each chemical packet) from brackish water containing dissolved solids upto 7000 mg/l yielding in all 3.6 litres of potable water sufficient for a man to survive for a day. |
