Power MOSFET Thermal Instability Operation Characterization Support

Metal-oxide semiconductor field-effect transistors (MOSFETs) are used extensively in flight hardware and ground support equipment. In the quest for faster switching times and lower "on resistance," the MOSFETs designed from 1998 to the present have achieved most of their intended goals. In the quest for lower on resistance and higher switching speeds, the designs now being produced allow the charge-carrier dominated region (once small and outside of the area of concern) to become important and inside the safe operating area (SOA). The charge-carrier dominated region allows more current to flow as the temperature increases. The higher temperatures produce more current resulting in the beginning of thermal runaway. Thermal runaway is a problem affecting a wide range of modern MOSFETs from more than one manufacturer. This report contains information on MOSFET failures, their causes and test results and information dissemination

Cascading effects of a highly specialized beech-aphid–fungus interaction on forest regeneration

Specialist herbivores are thought to often enhance or maintain plant diversity within ecosystems, because they prevent their host species from becoming competitively dominant. In contrast, specialist herbivores are not generally expected to have negative impacts on non-hosts. However, we describe a cascade of indirect interactions whereby a specialist sooty mold (Scorias spongiosa) colonizes the honeydew from a specialist beech aphid (Grylloprociphilus imbricator), ultimately decreasing the survival of seedlings beneath American beech trees (Fagus grandifolia). A common garden experiment indicated that this mortality resulted from moldy honeydew impairing leaf function rather than from chemical or microbial changes to the soil. In addition, aphids consistently and repeatedly colonized the same large beech trees, suggesting that seedling-depauperate islands may form beneath these trees. Thus this highly specialized three-way beech-aphid–fungus interaction has the potential to negatively impact local forest regeneration via a cascade of indirect effects

Design and Early In-flight Performance of the Tropical Rainfall Measuring Mission (TRMM) Power Subsystem

Maryland built the spacecraft in-house with four U.S. instruments and one Japanese instrument, the first space flown Precipitation Radar (PR). The TRMM Observatory was successfully launched from Tanegashima Space Center in Japan on an H-2 Expendable Launch Vehicle on November 27, 1997. This paper presents an overview of the TRMM Power System including its design, testing, and in flight performance for the first 70 days. Finally, key lessons learned are presented. The TRMM power system consists of an 18.1 square meter deployed solar array fabricated by TRW with Tecstar GaAs/Ge cells, two (2) Hughes 50 Ampere-Hour (Ah) Super NiCd' batteries, each with 22 Eagle-Picher cells, and three (3) electronics boxes designed to provide power regulation, battery charge control, and command and telemetry interface

Radio Astronomy

Contains reports on three research project.National Science Foundation (Grant GP-21348A#2)California Institute of Technology (Contract 952568)National Aeronautics and Space Administration (Grant NGR 22-009-421)U. S. Air Force - Electronic Systems Division (Contract F19628-73-C-0196

Three (Potential) Pillars of Transnational Economic Justice: The Bretton Woods Institutions as Guarantors of Global Equal Treatment and Market Completion

This essay aims to bring two important lines of inquiry and criticism together. It first lays out an institutionally enriched account of what a just world economic order will look like. That account prescribes, via the requisites to that mechanism which most directly instantiate the account, three realms of equal treatment and market completion - the global products, services, and labor markets; the global investment/financial markets; and the global preparticipation opportunity allocation. The essay then suggests how, with minimal if any departure from familiar canons of traditional international legal mandate interpretation, each of the Bretton Woods institutions - particularly the GATT/WTO and the IMF - can be viewed at least in part as charged with the task of fostering equal treatment and ultimate market completion within one of those three realms. The piece then argues that one of the institutions in particular - the World Bank - has, for reasons of at best negligent and at worst willful injustice on the part of influential state actors in the world community, fallen farthest short in pursuit of what should be viewed as its proper mandate. The article accordingly concludes that a fuller empowerment of the Bank to effect its ideal mission will press the Bretton Woods system more nearly into ethical balance, and with it the world into justice; and that full empowerment of the GATT/WTO and IMF should be partly conditioned upon the fuller empowerment of the Bank