Scalar variational analysis of single mode,graded-core,W-type fibres

A scalar variational analysis for the fundamental mode of a graded-core, W-type fibre based on single and two parameter trial fields has been presented. Comparison with the exact numerical results shows that the two parameter trial field estimates the propagation characteristics accurately.On study leave from Physics Department, G.M. College, Sambalpur-768004, India.     

Stationary lower probabilities and unstable averages

Summary This paper explores the possibilities for probability-like models of stationary nondeterministic phenomena that possess divergent but bounded time averages. A random sequence described by a stationary probability measure must have almost surely convergent time averages whenever it has almost surely bounded time averages. Hence, no measure can provide the mathematical model we desire. In turning to lower probability based models we first explore the relationships between divergence, stationarity, and monotone continuity and those between monotone continuity and unicity of extensions. We then construct several examples of stationary lower probabilities for sequences of uniformly bounded random variables such that divergence of time averages occurs with lower probability one. We conclude with some remarks on the problem of estimating lower probability models on the basis of cylinder set observations.     

Thermal conduction through loose and granular two-phase materials at normal pressure

The integrated theory derived for the lattice-type dispersions is modified and extended to estimate the effective thermal conductivity of loose and granular two-phase materials at normal pressure assuming an effective continuous media approximation. A comparison of calculated values ofλ _e with the reported experimental results over a wide range of loose and granular two-phase materials shows a good agreement.     

Effective thermal conductivity of granulated two-phase systems at interstitial air pressures

Considering the htermal conduction through molecular collisions an expression for the effective thermal conductivityλ _e of loose and granular two-phase materials at different interstitial air pressure has been derived. The dependence ofλ _e on pore and particle sizes, characteristic pressure and radiative heat transfer is also discussed. Calculated values ofλ _e of glass beads and loose building materials are compared with reported results.     

Microdetermination of indoles with N-bromoacetamide in acetic acid medium

Summary A titrimetric method for the microdetermination of indole and its derivatives withN-bromoacetamide is described. It has been observed thatN-bromoacetamide brominates the compound containing indole nucleus in the presence of acetic acid. The usual reaction time is 15 minutes and the reaction is carried out at room temperature. The relative errors are less than ±1.5% at the mg level.

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Zusammenfassung Die maßanalytische Bestimmung von Indol und seinen Derivaten mitN-Bromacetamid wurde beschrieben. Dieses Reagens bromiert in Gegenwart von Essigsäure indolhältige Verbindungen innerhalb 15 min bei Zimmertemperatur. Der rel. Fehler ist geringer als ±1,5%.

     

Bounds on the effective thermal conductivity of two-phase systems

The weighted geometric mean of resistors considered for determining the effective thermal conductivityK _E of two-phase systems has been optimised. Solutions of the equations lead to a useful set of bounds. When compared with other bounds the present bounds give the better results in estimating the upper and lower values of the effective thermal conductivity of a two-phase system.     

On the effects of uniform high suction on the steady hydromagnetic flow due to a rotating disc

Summary The effect of uniform high suction on the steady flow of conducting viscous liquid due to a rotating disc, in the presence of a transverse magnetic field is considered. Series solutions for velocity components are obtained in descending powers of the suction parameter (a). The solutions, thus obtained, are valid for small values of m (= B ₀ ² /). Tables for displacement thickness, momentum thickness, and velocity components are given for different values of a and m.     

The Ricci identity

Summary The Ricci identities have been established by C.I. Ispas [1] and H. Rund [2] in a Finsler space. Here we shall discuss some identities based on the principle of mathematical induction [3], [4].     

Low temperature heat capacity of LaRu2 by a.c. technique

The low temperature heat capacity data of a small bulk sample of LaRu₂ show that the structural transformation occurring at T_m ～ 29.5K is rather spread out. The electronic heat capacity coefficient, γ, and Debye temperature, θ_D, are found to be respectively $\text{8.5}\text{mJ}\text{g}$. atom K² and 164 K. The multiple anomalies below T_m and T_c (4.45 K) are discussed.