Multidisciplinary research leading to utilization of extraterrestrial resources Quarterly status report, 1 Oct. 1967 - 1 Jan. 1968

Developing extraterrestrial resources technologies for using lunar and planetary resources to support manned mission

A mathematical model for assessment of material requirements for cable supported bridges: implications for conceptual design

Recent technological developments have led to improvements in the strengths of materials, such as the steel and wire ropes used in the construction of cable supported bridges. This, combined with technological advancements in construction, has encouraged the design of structures with increasing spans, leaving the question of material and environmental costs behind. This paper presents a refined mathematical model for the assessment of relative material costs of the supporting structures for cable-stayed and cable suspension bridges. The proposed model is more accurate than the ones published to date in that it includes the self weight of the cables and the pylons. Comparisons of material requirements for each type of bridge are carried out across a range of span/dip ratios. The basis of comparison is the assumption that each structure is made of the same material (steel) and carries an identical design load, q, exerted by the deck. Calculations are confined to a centre span of a three-span bridge, with the size of the span ranging from 500 m to 3000 m. Results show that the optimum span/dip ratio, which minimises material usage, is 3 for a cable-stayed (harp type) bridge, and 5 for a suspension structure. The inclusion of the self weight of cable in the analysis imposes limits on either the span, or span/dip ratio. This effect is quantified and discussed with reference to the longest cable-supported bridges in the world completed to date and planned in the future

AN ANALYSIS OF THE POTENTIAL FOR INCREASED DIRECT MARKETING OF SMALL FRUITS AND VEGETABLES IN THREE WEST VIRGINIA COUNTIES

Marketing,

Code optimisation in a nested-sampling algorithm

The speed-up in program running time is investigated for problems of parameter estimation with Nested Sampling Monte Carlo methods. The example used in this study is to extract a polarization observable from event-by-event data from meson photoproduction reactions. Various implementations of the basic algorithm were compared, consisting of combinations of single threaded vs multi-threaded, and CPU vs GPU versions. These were implemented in OpenMP and OpenCL. For the application under study, and with the number of events as used in our work, we find that straightforward multi-threaded CPU OpenMP coding gives the best performance; for larger numbers of events, OpenCL on the CPU performs better. The study also shows that there is a “break-even” point of the number of events where the use of GPUs helps performance. GPUs are not found to be generally helpful for this problem, due to the data transfer times, which more than offset the improvement in computation time

Space shuttle: Structural integrity and assessment study

A study program was conducted to determine the nondestructive evaluation (NDE) requirements and to develop a preliminary nondestructive evaluation manual for the entire space shuttle vehicle. The rationale and guidelines for structural analysis and NDE requirements development are discussed. Recommendations for development of NDE technology for the orbiter thermal protection system and certain structural components are included. Recommendations to accomplish additional goals toward space shuttle inspection are presented

Representation of Lesbian and Gay Men in Federal, State, and Local Bureaucracies

Americans increasingly view lesbians and gay men as a legitimate minority, entitled to equal employment opportunities and perhaps to adequate representation in government. Scholars of public administration have extensively studied whether women and racial minorities receive fair representation and pay in the public sector, but we have generally ignored lesbians and gay men, largely because we lack data on the sexual orientation of government employees. Using a 5 percent sample of the 2000 Census, this paper provides new insights into one group of lesbian and gay employees: full-time workers with same-sex unmarried partners. It first determines whether they are as likely to hold jobs in the public and nonprofit sectors as workers who are married, have different-sex unmarried partners, or have never been married. Second, it explores whether lesbians' and gay men's representation is concentrated in particular occupations. It then examines whether workers with same-sex partners earn as much as other workers, and whether any disparities can be explained by race, gender, education, age, occupation, and location. Working Paper 08-2