STRUCTURAL THERMO-MECHANICS

A method has been elaborated for the dimensioning and design of heat isulated vessels, through which the mechanical element can be given thermo-dynamical and the thermotechnical element can be given strength function. In the case of plane-walled vessels we achieved a rather favourable design. Vessels dimensioned in this way contain considerably less steel and have a more advantageous heat isulation. A further result is the generalized method elaborated for the optimal design of multi-element, multi-function structures

THERMODYNAMICS OF COMPLEX SYSTEMS: SPECIAL PROBLEMS OF COUPLED THERMAL AND MOISTURE FIELDS AND APPLICATION TO TAILORING OF COMPOSITES

In case of composites it is possible to increase the effectiveness of tailoring by involving new parameters, but utilizing special symmetries the enormous increase of needed numerical values can be avoided. Starting with the basic equations of thermo-hygro materials the special features and parameters are shown. Finally, some practical applications to the tailoring of fiber reinforced composites are displayed

Newtonian and Post-Newtonian approximations of the k = 0 Friedmann Robertson Walker Cosmology

In a previous paper we derived a post-Newtonian approximation to cosmology which, in contrast to former Newtonian and post-Newtonian cosmological theories, has a well-posed initial value problem. In this paper, this new post-Newtonian theory is compared with the fully general relativistic theory, in the context of the k = 0 Friedmann Robertson Walker cosmologies. It is found that the post-Newtonian theory reproduces the results of its general relativistic counterpart, whilst the Newtonian theory does not.Comment: 11 pages, Latex, corrected typo

Perceptions of date rape on a college campus

The occurrences and attitudes about date rape were surveyed at a small Midwestern college campus. They were measured through a vignette in which a date rape occurred, and a survey which contained demographic questions, true/false and Likert scale items. The Likert items were divided into three types: 1) nine questions a date rapist would strongly agree with (male initiator items); 2) nine questions someone sophisticated about rape would strongly agree with (egalitarian items); and 3) three neutral questions (bystander items). From these items a male-initiator and egalitarian score was derived for each S. T-test results indicate that male Ss had a higher male-initiator score than female Ss, 1(329) = 2.04, a \u3c .001, while female Ss had a higher egalitarian score than male Ss, t(328) = 1.18, a\u3c .001. Pearson correlations also revealed a significant negative relationship between male-initiator and egalitarian scores, r = -.61, p_\u3c .001; and a significant positive relationship between the age of the Ss and their egalitarian score, r = .14, p.= .006. This study advocates the need to dispel traditional myths concerning sex roles and date rape through rape awareness and open communication

A Radiation Scalar for Numerical Relativity

This letter describes a scalar curvature invariant for general relativity with a certain, distinctive feature. While many such invariants exist, this one vanishes in regions of space-time which can be said unambiguously to contain no gravitational radiation. In more general regions which incontrovertibly support non-trivial radiation fields, it can be used to extract local, coordinate-independent information partially characterizing that radiation. While a clear, physical interpretation is possible only in such radiation zones, a simple algorithm can be given to extend the definition smoothly to generic regions of space-time.Comment: 4 pages, 1 EPS figur

Simple Analytic Models of Gravitational Collapse

Most general relativity textbooks devote considerable space to the simplest example of a black hole containing a singularity, the Schwarzschild geometry. However only a few discuss the dynamical process of gravitational collapse, by which black holes and singularities form. We present here two types of analytic models for this process, which we believe are the simplest available; the first involves collapsing spherical shells of light, analyzed mainly in Eddington-Finkelstein coordinates; the second involves collapsing spheres filled with a perfect fluid, analyzed mainly in Painleve-Gullstrand coordinates. Our main goal is pedagogical simplicity and algebraic completeness, but we also present some results that we believe are new, such as the collapse of a light shell in Kruskal-Szekeres coordinates.Comment: Submitted to American Journal of Physic

Integer Partitions and Exclusion Statistics

We provide a combinatorial description of exclusion statistics in terms of minimal difference $p$ partitions. We compute the probability distribution of the number of parts in a random minimal $p$ partition. It is shown that the bosonic point $p=0$ is a repulsive fixed point for which the limiting distribution has a Gumbel form. For all positive $p$ the distribution is shown to be Gaussian.Comment: 16 pages, 4 .eps figures include

No-Go Theorem in Spacetimes with Two Commuting Spacelike Killing Vectors

Four-dimensional Riemannian spacetimes with two commuting spacelike Killing vectors are studied in Einstein's theory of gravity, and found that no outer apparent horizons exist, provided that the dominant energy condition holds.Comment: latex, 1 figure, version published in Gen. Relativ. Grav., 37, 1919-1926 (2005