Solar dynamic power for space station freedom

The Space Station Freedom Program is presently planned to consist of two phases. At the completion of Phase 1, Freedom's manned base will consist of a transverse boom with attached manned modules and 75 kW of available electric power supplied by photovoltaic (PV) power sources. In Phase 2, electric power available to the manned base will be increased to 125 kW by the addition of two solar dynamic (SD) power modules, one at each end of the transverse boom. Power for manned base growth beyond Phase 2 will be supplied by additional SD modules. Studies show that SD power for the growth eras will result in life cycle cost savings of $3 to$4 billion when compared to PV-supplied power. In the SD power modules for Space Station Freedom, an offset parabolic concentrator collects and focuses solar energy into a heat receiver. To allow full power operation over the entire orbit, the receiver includes integral thermal energy storage by means of the heat of fusion of a salt mixture. Thermal energy is removed from the receiver and converted to electrical energy by a power conversion unit (PCU) which includes a closed brayton cycle (CBC) heat engine and an alternator. The receiver/PCU/radiator combination will be completely assembled and charged with gas and cooling fluid on Earth before launch to orbit. The concentrator subassemblies will be pre-aligned and stowed in the orbiter bay before launch. On orbit, the receiver/PCU/radiator assembly will be installed as a unit. The pre-aligned concentrator panels will then be latched together and the total concentrator attached to the receiver/PCU/radiator by the astronauts. After final electric connections are made and checkout is complete, the SD power module will be ready for operation

EMPIRICAL LIKELIHOOD ESTIMATORS OF THE LINEAR SIMULTANEOUS EQUATIONS MODEL

Information theoretic estimators are specified for a system of linear simultaneous equations, including maximum empirical likelihood, maximum empirical exponential likelihood, and maximum log Euclidean likelihood. Monte Carlo experiments are used to compare finite sample performance of these estimators to traditional generalized method of moments.Research Methods/ Statistical Methods,

Do Trustees and Administrators Matter? Diversifying the Faculty Across Gender Lines

Our paper focuses on the role that the gender composition of the leaders of American colleges and universities – trustees, presidents/chancellors, and provosts/academic vice presidents – plays in influencing the rate at which academic institutions diversify their faculty across gender lines. Our analyses make use of institutional level panel data that we have collected for a large sample of American academic institutions. We find, other factors held constant including our estimate of the “expected” share of new hires that should be female, that institutions with female presidents/chancellors and female provosts/academic vice presidents, as well as those with a greater share of female trustees, increase their shares of female faculty at a more rapid rate. The magnitudes of the effects of these leaders are larger at smaller institutions, where central administrators may play a larger role in faculty hiring decisions. A critical share of female trustees must be reached before the gender composition of the board matters

So you want to farm : what does it take? What can you make?

"Farming means different things to different people. To some, it is a business in which farm managers employ their talents in producing food and fiber, thereby earning a return for their labor and equity. To others, it is a way of life - a good place to raise a family and escape some of the frustrations of urban living. If a farm does not have to support a family, it can be a good investment and greatly add to the family's living and enjoyment."--First page.Ronald L. Plain and Thomas G. Brown (Department of Agricultural Economics, College of Agriculture)Revised 12/86/6

A Pavement Design and Management System for Forest Service Road : A Conceptual Study

See this work in the Center for Transportation Research Library catalog: https://library.ctr.utexas.edu/Presto/catalogid=5738The design of pavements for low-cost, low-volume roads is a complex procedure involving numerous variables. Because of the development of new information in the pavement field during the past decade, the complexity of the interaction of these design variables has become better understood and the need for a systematic approach to the problem of pavement design and management has become evident. This report is an attempt to apply this systematic approach to the design and management of low-volume Forest Service roads. The report summarizes the problem analysis efforts of the project staff, beginning with the identification of the problem through its recognition and definition. Using the FPS type of working Pavement Design System developed in Texas as a conceptual base, an extensive examination of the major subsystems that make up the majority of existing pavement management systems for "higher type" roads was conducted. In attempting to define these basic components for the proposed low-volume road system, it was found that interaction between the project research staff and Forest Service personnel was of great importance. This interaction was achieved in the form of an interagency "brainstorming session" and later an "importance rating" of the ideas presented at this meeting. The results of this interaction along with the research efforts of the project staff allowed for an initial definition of the major components in the proposed system. Where complete definition of these subsystems was not possible, relevant questions and ideas were formulated for consideration in their further development. Finally, an example conceptual pavement management system for low-volume roads that incorporates all the ideas and concepts developed during the past year's research is presented. It is concluded that the development of pavement management systems for low-volume Forest Service roads is indeed feasible and should be pursued in Phase II of the project. Recommendations for major areas of further research are also given.Forest Service U.S. Department of Agriculture; Department of Transportation Office of University Research (Washington D.C.)Center for Transportation ResearchSee this work in the Center for Transportation Research Library catalog

Alternative Liquid Fuels for Transportation

This paper reviews present studies at F.I.T. intended to identify, evaluate, and develop alternative liquid fuels for transportation which can be derived from biomass using noncapital intensive processes

Adrenocortical neoplasia: evolving concepts in tumorigenesis with an emphasis on adrenal cortical carcinoma variants

Adrenocortical carcinoma (ACC) is a rare, heterogeneous malignancy with a poor prognosis. According to WHO classification 2004, ACC variants include oncocytic ACCs, myxoid ACCs and ACCs with sarcomatous areas. Herein, we provide a comprehensive review of these rare subtypes of adrenocortical malignancy and emphasize their clinicopathological features with the aim of elucidating aspects of diagnostic categorization, differential diagnostics and biological behavior. The issue of current terminology, applied to biphasic tumors with pleomorphic, sarcomatous or sarcomatoid elements arising in adrenal cortex, is also discussed. We additionally present emerging evidence concerning the adrenal cortical tumorigenesis and the putative adenoma–carcinoma sequence as well