Remote sensing of air-sea interactions

A number of preliminary concepts for the measurement or inference of fluxes across the air-sea interface through remote sensing are proposed. All the methods are achievable from aircraft with state-of-the-art technology. Only one is now ready for space implementation. The focus is on cold outbreaks. Sensible (latent) heat flux is inferred from the difference between initial surface air temperature (vapor mixing ratio) and the downwind SST (and corresponding saturation mixing ratio). The downwind growth rate of the PBL as measured by lidar also provides estimates of surface heating and the cross-inversion entrainment velocity. The lidar also provides a measure of the depth of the inversion and its penetration by surface-forced convection; this permits estimates of the surface heat flux. Lidar and radiometric measurements of cloud top height and temperature provide means of deducing the temperature sounding downstream so that heating is computed with the aid of a known sounding upstream

Data correlation and analysis of arc tunnel and wind tunnel tests of RSI joints and gaps, phase 2. Volume 2: Data report, part 2

For abstract, see N75-28103

Labor Mobility in Bolivia: On-the-job Search Behavior of Private and Public Sector Employees

This paper estimates structural parameters of both a simple and an extended job separation model with the purpose of understanding constraints in the labor market in Bolivia. The results confirm the hypothesis that skilled labor is a scarce commodity in Bolivia, while unskilled labor is abundantly available. This implies that skilled employees shop around for alternative employment opportunities and quit their jobs when a better opportunity arises. The quit rate among skilled employees in the private sector is much higher than the quit rate among skilled employees in the public sector. The reverse is true for the lay-off rate, and together this suggests that the private sector has difficulties maintaining its skilled labor. The estimates of the wage sensitivity of job search effort parameters presented in this paper suggest that it would be difficult for the private sector to improve its capacity to retain skilled employees by increasing wages – skilled employees in the private sector do not seem to reduce their on-the-job search in response to higher wages. The results are consistent with the hypothesis that the public sector in Bolivia, inflated by high levels of foreign aid (about 10% of GDP), may be detracting scarce human resources from local productive sectors, potentially jeopardizing the opportunity for sustainable development.Mobility, on-the-job search, labor markets, Bolivia

The Static and Dynamic Benefits of Migration and Remittances in Nicaragua

This paper utilizes a unique three-wave panel of household data from Nicaragua, which allows a thorough exploration of the relationships between migration, remittances and household consumption. The paper distinguishes between the effects of emigration and the impacts of remittances received. There is a self-selection bias in the decision to send a migrant, as well as in the decision to receive remittances. To adequately correct for these selection biases, we develop a bivariate selection correction procedure. Perhaps surprisingly, the results show that households do not benefit (in terms of higher consumption growth) from receiving remittances, but rather from having migrants abroad. This suggests that not only money are remitted from abroad, but also something more subtle, which could be business ideas, belief systems, aspirations, patterns of social interaction, and other intangibles, which have been dubbed social remittances.Migration, Remittances, Social Remittances, Nicaragua, Bivariate Selection Correction

Silica heat shield sizing

The sensitivity of silica heat shield requirements to gap width, tile edge radius, and heat transfer distribution within tile gaps was investigated. A two-dimensional thermal model was modified and used to determine the effect of two dimensional heat transfer distributions at high temperature reusable surface insulation edges on shuttle thermal protection system (TPS) requirements. The sensitivity of TPS requirements to coating thickness, emissivity, substructure thickness, and changes in gap heating for several locations on shuttle was also studied. An inverse solution technique was applied to temperature data obtained in the Ames 20 MW turbulent duct in order to examine the effect of tile edge radius on TPS requirements. The derived heating values were then used to predict TPS requirements. Results show that increasing tile radius reduces TPS requirements

Data correlation and analysis of arc tunnel and wind tunnel tests of RSI joints and gaps. Volume 1: Technical report

Heat transfer data measured in gaps typical of those under consideration for joints in space shuttle reusable surface insulation protection systems have been assimilated, analyzed and correlated. The data were obtained in four NASA facilities. Several types of gaps were investigated with emphasis on simple butt joints. Gap widths ranged from 0.07 to 0.7 cm and depths ranged from 1 to 6 cm. Laminar, transitional and turbulent boundary layer flows over the gap opening were investigated. Three-dimensional heating variations were observed within gaps in the absence of external flow pressure gradients. Heat transfer correlation equations were obtained for several of the tests. Thermal protection system performance with and without gaps was compared for a representative shuttle entry trajectory

Mobilizing Public Will For Social Change

Examines the theory and strategies of "public will" campaigns and offers tangible criteria for their evaluation. It provides a rich inventory of strategies for use in mobilizing the public will through an integration of models of agenda building, social problem construction, issues management, social movements, media advocacy, and social capital. In addition, the paper provides cases and examples of public will campaigns directed at various social problems, along with criteria for evaluating these campaigns at various stages of a social problem's life cycle