Recirculation of a Two-phase Fluid by Thermal and Capillary Pumping

Closed-cycle gas supply system for gas bearings using thermal and capillary pumpin

Slit regulated gas journal bearing Patent

Slit regulated gas journal bearin

After the Epidemic: Recent Trends in Youth Violence in the United States

The epidemic of youth violence in the United States peaked in 1993 and has been followed by a rapid, sustained drop. In parallel with our earlier treatment (Cook and Laub 1998), we assess two types of explanation for this drop -- those that focus on 'cohort' effects (including the effects of abortion legalization) and those that focus on 'period' effects (including the effects of the changing crack-cocaine trade). Once again we are able to reject the cohort-type explanations, yet also find contradictions with an account based on the dynamics of crack markets. The 'way out' of this epidemic has not been the same as the 'way in.' The relative importance in homicide of youths, racial minorities, and guns, all of which increased greatly during the epidemic, has remained high during the drop. Arrest patterns tell a somewhat different story, in part because of changing police practice with respect to aggravated assault. Finally, we demonstrate that the rise and fall of youth violence has been narrowly confined with respect to race, sex, and age, but not geography. Given the volatility in the rates of juvenile violence, forecasting rates is a risky business indeed. Effectively narrowing the range of plausible explanations for the recent ups and downs may require a long time horizon, consideration of a broader array of problem behaviors, and comparisons with trends in other countries.

Swashplate control system

A mechanical system to control the position of a rotating swashplate is developed. This system provides independent lateral cyclic, longitudinal cyclic and collective pitch control of a helicopter rotor attached to the swashplate, without use of a mixer box. The system also provide direct, linear readout of cyclic and collective swashplate positions

Attitude control for spacecraft Patent

Attitude control device for space vehicle

Phase separation in transparent liquid-liquid miscibility gap systems

A program to be carried out on transparent liquid-phase miscibility gap materials was developed for the purpose of acquiring additional insight into the separation process occurring in these systems. The transparency feature allows the reaction to be viewed directly through light scattering and holographic methods

Airloads on bluff bodies, with application to the rotor-induced downloads on tilt-rotor aircraft

The aerodynamic characteristics of airfoils with several flap configurations were studied theoretically and experimentally in environments that simulate a wing immersed in the downwash of a hovering rotor. Special techniques were developed for correcting and validating the wind tunnel data for large blockage effects, and the test results were used to evaluate two modern blockage effects, and the test results were used to evaluate two modern computational aerodynamics codes. The combined computed and measured results show that improved flap and leading-edge configurations can be designed which will achieve large reductions in the downloads of tilt-rotor aircraft, and thereby improve their hover efficiency