Improved method for calculating pump thermodynamic suppression head

Method of calculation improves by introducing the sound velocity of two phase flow into the equation for the vapor to liquid volume ratio. Comparisons of required net positive suction head and thermodynamic suppression head are made for a head coefficient ratio of 0.98

The "Yin-Yang Grid": An Overset Grid in Spherical Geometry

A new kind of overset grid, named Yin-Yang grid, for spherical geometry is proposed. The Yin-Yang grid is composed of two identical component grids that are combined in a complemental way to cover a spherical surface with partial overlap on their boundaries. Each component grid is a low latitude part of the latitude-longitude grid. Therefore the grid spacing is quasi-uniform and the metric tensors are simple and analytically known. One can directly apply mathematical and numerical resources that have been written in the spherical polar coordinates or latitude-longitude grid. The complemental combination of the two identical component grids enables us to make efficient and concise programs. Simulation codes for geodynamo and mantle convection simulations using finite difference scheme based on the Yin-Yang grid are developed and tested. The Yin-Yang grid is suitable for massively parallel computers.Comment: 9 figure

On the intertemporal allocation of consumption, mortality and life-history strategies

This paper studies the bio-evolutionary origin of time preference. By examining human life-history strategies, it demonstrates that time discounting and mortality reflect the age-variation in the value of survival, which in turn depends on future reproduction and production. Consistent with empirical findings, it also suggests that our biologically endowed time preference is positive, reaches its lowest at around age twenty and increases thereafter, and is higher when exchange transactions involve a reduction in present consumption than when they involve an increase in present consumption.

Why do women in former communist countries look unhappy? A demographic perspective

This paper investigates the causes of the positive correlation between happiness and the sex gap in happiness between women and men observed in Europe. Departing from a variety of hypotheses that are based on the sex differences at the individual level, this paper tests whether the positive correlation can be explained by the sex difference in life expectancy. The mechanisms working behind are as follows. First, national average happiness affects the sex gap in life expectancy negatively because men are more fragile to stress (unhappiness). Second, the sex difference in life expectancy influences the sex gap in happiness negatively because it affects the chance of being a widow for women. Using a 3SLS approach, it found that both effects are significant and that the direct effects between happiness and the happiness gap are insignificant. These results indicate that the positive correlation between happiness and the happiness gap is an artifact of the demographic compositional effect resulted from the sex gap in life expectancy.Europe, economic and social development, life expectancy

Happiness and sex difference in life expectancy

This paper examines the effects of happiness on the sex gap in life expectancy. Utilizing a cross-country data set, it first inspects the reverse effect of the life expectancy gap on happiness and demonstrates that the life expectancy gap negatively affects happiness through the composition of marital status. Taking this reverse causality into account, it shows that happiness is significant on explaining the differences in the life expectancy gap between countries. As national average happiness increases, the sex difference in life expectancy decreases. This is consistent with the findings that psychological stress (unhappiness)adversely affects survival and that the effect of psychological stress on mortality is more severe for men. This result provides an indirect evidence that happiness affects survival even at the national aggregate level.economic and social development, life expectancy

Grothendieck rings of o-minimal expansions of ordered abelian groups

We will calculate completely the Grothendieck rings, in the sense of first order logic, of o-minimal expansions of ordered abelian groups by introducing the notion of the bounded Euler characteristic.Comment: to appear J. Algebr