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The concept of surface tension and surface energy of solids was used by Griffith to obtain a criterion for the extension of cracks in brittle materials. Griffith, however, neglected the stresses due to the normal traction at the crack implied by the surface tension. A complete solution to the problem of an elliptic hole in an infinite plate with surface tension loading at the hole is given. Complex potentials are given in closed form in terms of elliptic integrals of the first, second, and third kinds. Stress distributions are studied. For a flat crack, the nature of the singularity at the tip is shown to be radically different from that usually encountered in fracture mechanics. The implications of our analysis for theories of fracture in brittle materials are discussed.

A single map of the spread of an innovation produced from a Monte Carlo simulation is equivalent from the viewpoint of sampling theory to a random sample of size one drawn from the set of all possible maps. A sample mean is a more reliable estimator of the population mean when the sample size is large. In the simulation of diffusion the recommended practice has been to obtain an average map based on several repetitions of the simulation, but the average map can be produced directly in a few analytical steps, thus obviating the need for the cumbersome sampling procedure implicit in the Monte Carlo approach.

Introduction : Smoking and alcohol consumption among the estate population are considered to be high. However there is little documented evidence on the prevalence of smoking and alcohol consumption among female estate workers in Sri Lanka. The aim of this study was to find out the prevalence of smoking, alcohol and other dugs consumption among female estate workers and to find out factors associated with these habits. Methodology : A community based cross sectional study was carried out with a sample of 928 females on a presumptive prevalence of 10% of alcohol users, using simple random sampling technique. Data was collected by trained field public health midwives using an interviewer administered questionnaire. Statistical analysis of data was carried out using SPSS version 11. Results : The response rate was 97.8%. Prevalence of smoking, alcohol and other drugs were 7.27%, 34.7% and 0% respectively. Among smokers, most smoked cigar (55%), followed by Beedi (39%) and cigarette (6%). None indulged in dangerous drugs like Heroin and cannabis. Most consumed alcoholic beverage was toddy (64%) followed by arrack (31%). Seventy four percent of women stated that they consume alcohol because they were influenced by their husbands. A significant positive association was observed between smoking and (a)illiteracy (p

In the mature phloem of Tetragonia expansa strong ATPase activity is present on the plasmalemma of the companion cells and sieve tubes, and probably on the ER of the latter. The sieve tube wall sometimes shows a lead deposit. When the tissues is pre-treated with DNP there is often a diffuse deposit also on the P-protein and on the fibrillar protein from ruptured plastids. This is believed to be a diffusion artefact, and not to represent genuine P-protein activity.

The sieve tube slime of Tetragonia and Lycopersicum petiolar phloem was subjected to proteolytic enzymes both before and after embedding and sectioning. Subsequent electron microscopical examination confirmed that the fibrillar material is protein in nature, and provided evidence that the protein is acidic rather than basic.

The nature and the frequency of communication inputs among Indian farmers are key correlates of the pattern of diffusion of modern farm practices. In a country where mass media is urban centered and its extensions somewhat limited, rural communication will continue to be conducted primarily along interpersonal oral channels1 [17, pp. 24-29]. After a survey of development communication in several Indian villages Dube [4] concludes that a mechanism to convey information to the village people already exists in India. He suggests that the traditional channels, working in conjunction with some of the newly created ones, were reasonably adequate as carriers of information. But he observed

Measurements have been made of heat transfer through gas mixtures containing atomic and molecular oxygen. In the presence of catalytic surfaces, the collisional energy transfer is augmented by chemical enthalpy transport. The magnitude of the increase in heat flux is a function of atom density, total gas pressure, and catalytic surface activity. The relative values of the thermal accommodation coefficient of atomic and molecular oxygen are deduced from the changes in temperature jump distances. Also, a theoretical analysis is presented of heat conduction through a gas located between coaxial cylinders of different length.

Although one of the main aims of many national-spatial studies for decentralization is to keep the population from concentrating in certain areas, modern economic industrial growth is said to require the spatial concentration of the means of production. The article discusses what degree of decentralization is acceptable without sacrificing productivity to an unreasonable degree. The question is then examined of how far the means of production can be centralized in order to maximise GNP and prevent a level of population concentration considered socially undesirable. The importance of commuting then becomes an important aspect of transport policy as the availability of a high-speed, efficient, low cost public and private transportation network means that the residential population can remain in a more dispersed pattern than that of their workplaces. (TRRL)