Shape correction of thin mirrors in a reconfigurable modular space telescope

In order to facilitate the construction of future large space telescopes, the development of low cost, low mass mirrors is necessary. However, such mirrors suffer from a lack of structural stability, stiffness, and shape accuracy. Active materials and actuators can be used to alleviate this deficiency. For observations in the visible wavelengths, the mirror surface must be controlled to an accuracy on the order of tens of nanometers. This paper presents an exploration of several mirror design concepts and compares their effectiveness at providing accurate shape control. The comparison test is the adjustment of a generic mirror from its manufactured spherical shape to the shape required by various off-axis mirrors in a segmented primary mirror array. A study of thermal effects is also presented and, from these results, a recommended design is chosen

A double gender-family inequality phenomenon in the international mobility of young researchers

In this paper, we raise the question of gender differences in the geographic mobility of young researchers. We try to answer to three main questions regarding the international mobility of young researchers during the post-doc period: Are there differences among genders? Does “family” have an impact? Is the effect of family related variables similar among genders? With a French survey, we find that if postdoc is as common for women as for men, females are less mobile internationally, especially in direction of the United States. The impact of the “family” on the probability of taking a postdoc position and on the location of postdoc is different among genders. Married women take less frequently such appointments and, when they do so, they are less mobile internationally. There are no similar effects for males.migration; geographical mobility; brain drain; immigrants; family; skilled labor; doctorate; gender gap

Understanding Svocs

Semi-volatile organic compounds (SVOCs) are an important class of indoor pollutants that are of great health concern. However, they have not received much attention within the ASHRAE community. This column provides an overview of the sources, sinks, transport mechanisms, and potential health effects, and discusses how HVAC systems may affect occupants' exposure to SVOCs.Mechanical Engineerin