Generator for a space power system Patent

Design and development of electric generator for space power syste

Investigation to identify paint coatings resistive to microorganism growth

All selected coatings contain nutrients that support microbial growth and survival. Incorporation of microbiocidal agents into coatings more susceptible to attack is recommended for improved inhibition of microorganism growth and for increased protection against deterioration of coatings by microorganisms

Shuttle orbiter radar cross-sectional analysis

Theoretical and model simulation studies on signal to noise levels and shuttle radar cross section are described. Pre-mission system calibrations, system configuration, and postmission system calibration of the tracking radars are described. Conversion of target range, azimuth, and elevation into radar centered east north vertical position coordinates are evaluated. The location of the impinging rf energy with respect to the target vehicles body axis triad is calculated. Cross section correlation between the two radars is presented

The Cost of Labor Adjustment: Inferences from the Gap

We study labor adjustment costs. We specify a dynamic optimization problem at the plant-level, allowing for both convex and non-convex adjustment costs. We estimate the parameters of the adjustment process using an indirect inference procedure in which simulated moments are matched with data moments. For this study we use estimates of reduced-form adjustment functions obtained by the gap methodology' reported in Caballero-Engel as data moments. Contrary to evidence at the micro level in support of non-convex adjustment costs, our findings indicate that piecewise quadratic adjustment costs are sufficient to match these aggregate moments.

The health hazards of unemployment and poor education: the socioeconomic determinants of health duration in the European Union

The effect of socioeconomic status on the likelihood that an individual enters a period of poor health is examined using an Accelerated Failure Time methodology. This study employs data from the European Community Household Panel for the years 1994-2002 across 13 European countries, using the Physical and Mental Health Problems, Illnesses and Disabilities measure of physical health. Some socioeconomic status indicators do impact on the length of time an individual remains in good health – these being unemployment, which has a negative effect, and education, which has a positive effect – but others, such as income, have far less of an impact. Age and gender effects are also found.European Commission, Fifth Framework Programme “Quality of Life and Management of Living Resources” (contract number: QLRT-2001-02292)

Dollarization and the conquest of hyperinflation in divided societies

This study argues that the delegation of monetary policy control by one country to another can reduce inflation in the delegating country. Hyperinflation is common in a divided society, one in which special interest groups can pressure a weak central government to issue money to finance their own demands while neglecting the country’s overall welfare. A commitment device like dollarization or a currency board, which gives control of the divided country’s money supply to another country, can eliminate this inflation bias. This is illustrated by Argentina’s experience with inflation and a currency board which, in effect, gave control of Argentina’s money supply to the United States. This argument is made precise using a two-country overlapping generations model to study the effects of delegation. The study also finds that a dollarization treaty between the two countries can be welfare-improving for bothDollarization

Fatigue properties of shuttle thermal protection system

Static and cyclic load tests were conducted to determine the static and fatigue strength of the RIS tile/SIP thermal protection system used on the orbiter of the space shuttle. The material systems investigated include the densified and undensified LI-900 tile system on the .40 cm thick SIP and the densified and undensified LI-2200 tile system on the .23 cm (.090 inch) thick SIP. The tests were conducted at room temperature with a fully reversed uniform cyclic loading at 1 Hertz. Cyclic loading causes a relatively large reduction in the stress level that each of the SIP/tile systems can withstand for a small number of cycles. For example, the average static strength of the .40 cm thick SIP/LI-900 tile system is reduced from 86 kPa to 62 kPa for a thousand cycles. Although the .23 cm thick SIP/LI-2200 tile system has a higher static strength, similar reductions in the fatigue strength are noted. Densifying the faying surface of the RSI tile changes the failure mode from the SIP/tile interface to the parent RSI or the SIP and thus greatly increases the static strength of the system. Fatigue failure for the densified tile system, however, occurs due to complete separation or excessive elongation of the SIP and the fatigue strength is only slightly greater than that for the undensified tile system

Microwave diode amplifiers with low intermodulation distortion

Distortions can be greatly reduced in narrow-band applications by using the second harmonic. The ac behavior of simplified diode amplifier has negative resistance depending on slope of equivalent I-V curve

Is unemployment and low income harmful to health? : Evidence from Britain

ACKNOWLEDGEMENTS The authors thank Ian McAvinchey for helpful comments. FUNDING This work was financially supported by the European Commission under the Fifth Framework Programme “Quality of Life and Management of Living Resources” [grant number QLRT-2001-02292].Peer reviewedPostprin