An integrated in-space construction facility for the 21st century

Preliminary results are presented of studies being conducted by NASA on the construction of very large spacecraft. The various approaches are discussed for constructing spacecraft and their relative merits. It is observed that the Space Station Freedom has all of the basic design characteristics to permit its growth into an in-space construction facility for very large spacecraft. Also it is noted that if disturbances from construction operations are intolerable to other Space Station experiments, a co-orbiting construction facility could be built using previously developed Space Station truss hardware and systems. A discussion is also presented of a new PATHFINDER research initiative on on-orbit construction. This research effort is aimed at developing construction methods for very large spacecraft and includes the development of a 100 meter long space crane

Preliminary design of a large tetrahedral truss/hexagonal heatshield panel aerobrake

An aerobrake structural concept is introduced which consists of two primary components: (1) a lightweight erectable tetrahedral support truss; and (2) sandwich hexagonal heatshield panels which, when attached to the truss, form a continuous impermeable aerobraking surface. Generic finite element models and a general analysis procedure to design tetrahedral truss/hexagonal heatshield panel aerobrakes is developed, and values of the aerobrake design parameters which minimize mass and packaging volume for a 120-foot-diameter aerobrake are determined. Sensitivity of the aerobrake design to variations in design parameters is also assessed. The results show that a 120-foot-diameter aerobrake is viable using the concept presented (i.e., the aerobrake mass is less than or equal to 15 percent of the payload spacecraft mass). Minimizing the aerobrake mass (by increasing the number of rings in the support truss) however, leads to aerobrakes with the highest part count

An Unsolicited Sociotechnical Intervention in a Public System: A Participatory Action Research Approach

This research concerns itself with Participatory Action Research in a hostile setting. The thrust is a sociotechnical one, with the intent being to enhance the capacity of the Wallop Public School System, Wallop, USA, to address its problem of racial disparate treatment of Black children. The potential for Organizational Learning among the school system\u27s senior staff is studied. Some new theory about such hostile interventions is proposed. Also discussed are questions about reliability and construct validity within the context of the multiple role playing that an interventionist has in this setting. The role of the press is reflected in the intervention reporting. Some probes are also posed concerning the role of the technical skill level of participants in any sociotechnical intervention. Linear programming and traditional statistics are used to develop a measure of full racial integration and a pupil assignment model for racial balance

Louisiana Barrier Island Change Analysis Derived From a Geographic Information System (GIS) Based on Sequential Aerial Photography.

Surface feature maps were derived from color-infrared aerial photographs for Louisiana\u27s Timbalier Island and Eastern Isles Dernieres. These provided a basis for the implementation of a barrier island Geographic Information System (GIS), a quantitative spatial framework through which specific proximal and temporal interactions could be examined. This system was utilized to observe relationships between changes in island shorelines and surface areas relative to location and extent of island cover categories. It was further employed to test the applicability of the rollover and deltaic barrier cycle models of island dynamics within the context of the Louisiana coastal environment. Both islands exhibited significant changes, including net losses in island width and surface area. However, results indicated that areas containing marsh or swale experienced significantly lower rates of shoreline erosion than other areas. Combining shoreline change data from this study with that from previous studies indicated a consistent long-term trend of shoreline retreat. Based on these combined observations, Timbalier Island can be expected to persist through the year 2140, and the Eastern Isles Dernieres through 2040. The rollover model (Godfrey and Godfrey, 1974) describes a shoreward migration of barrier islands in response to increasing sea levels. The deltaic barrier cycle (Penland and Boyd, 1981) describes a sequence of stages associated with the formation, abandonment, and eventual subsidence of major river deltas. Neither Timbalier Island nor the Eastern Isles Dernieres showed significant accretion on their bay sides, precluding any net landward migration, responses fundamentally inconsistent with the rollover model. Timbalier Island underwent a steady westward lateral migration, consistent with the flanking barrier stage of the deltaic barrier cycle. However, the Eastern Isles Dernieres, which represents the transgressive barrier arc stage, exhibited a westward, rather than eastward lateral migration and no net landward migration, responses inconsistent with the deltaic barrier cycle model

A systems based stress reduction psychological education program for emergency veterinary personnel: development and evaluation

Conventional veterinary training equips veterinarians with skills to treat medical problems with animals. Until recently little emphasis has been placed on the human aspects of veterinary training and treatment. With the identification of the Human/Companion Animal Bond as a distinct area of scientific investigation, an increased awareness in this human factor in veterinary work has begun to emerge. To address the human factor, this study set out to evaluate the effectiveness of a training program developed to equip veterinarians with intervention skills and knowledge of family emotional process.;One, if not the most stressful, aspects of veterinary work reported by clinicians was dealing with anxious pet owners. The rationale for this study was to equip veterinarians with family psychotherapy theory and methodology to better handle anxious pet owners, thus reducing job stress for veterinarians.;The training program developed offered fifteen contact hours. The training was experience based learning as well as conventional didactic presentation.;The population was selected from among the staffs of two emergency veterinary clinics. For the pre-post control group design, one clinic comprised the treatment group and the other the control group. Pre and post testing was conducted on the dimensions of clinician anxiety level and level of clinician empathic response. These measures were taken after simulated pet/owner interviews which employed trained actors as pet owners and real pets as identified patients. Each of these simulated interviews was videotaped as part of the evaluation process.;The research findings were statistically significant supporting a treatment effect on the dimension of increased empathy expressed by the clinician. The anxiety results were inconclusive in that raw scores on this measure suggested the presence of socially desirable scoring patterns.;The scoring patterns for the treatment and control groups combined with their subjective evaluations of the training lend support to the need for training in this area. Implications for future training and research in veterinary stress management training are addressed

Projecting the Long Arm of the Law: Extraterritorial Criminal Enforcement of U.S. Antitrust Laws in the Global Economy

In this Article, I review the development, expansion, and current state of extraterritorial enforcement in the United States, look briefly at the presence or prospects of extraterritorial jurisdiction elsewhere, identify some of the problems presented by the unilateral exercise of extraterritorial jurisdiction, and suggest a view of the future