Miniature Optical Wide-Angle-Lens Startracker (Mini-OWLS)

This paper provides a brief overview of the design considerations and the current status of the Miniature Optical Wide-Angle Lens Startracker Program. Mini-OWLS offers a revolutionary alternative to the conventional startracker. It is a small, lightweight, low cost, high performance startracker that can be used in a variety of applications including calibration and alignment of Inertial Measurement Units (IMU's) Mini-OWLS makes use of a strap down design incorporating Holographic Optical Elements (HOES) in place of conventional optics. HOES can be multiplexed so that the same aperture can be used for multiple separate optical paths looking in several directions simultaneously without startracker rotation. Additionally, separate Schmidt corrector plates are not required to compensate for spherical aberration. The optical assembly, or what would normally be considered as the telescope, is less than 20 cc in volume, weighs less than 55 grams, and contains the equivalent of three individual telescopes. Each one has a 4 deg Field of View (FOV) with a field of regard of 48 square degrees. Mini-OWLS has a bandwidth of approximately 300 nm in or near the visible wavelength. The projected resolution of the startracker is 5 to 10 arcseconds, depending on the centroiding algorithm used. The Mini-OWLS program was initiated last year and represents a miniaturized version of a similar design for aeronautical applications. The contract is managed by Wright Laboratory, Air Force Systems Command, Wright-Patterson AFB, Ohio, with funding from the Strategic Defense Initiative Organization through Eglin AFB. The initial phase of the program is to build and test a development unit. The second phase is to integrate the startracker with the Charles Stark Draper Laboratory Micromechanical Inertial Guidance System (MIGS) and the Signal Processing Packaging Design (SPPD) being developed by Texas Instruments. The preliminary design review was conducted in November 1991. Three-axes prototype telescope assemblies have been built and design evaluation tests initiated

William G. Brownlow: Fighting Parson of the Southern Highlands

https://trace.tennessee.edu/utk_appalachian-echoes/1004/thumbnail.jp

Constructivism in Lost Wax

It was the purpose of this study to (1) explore the potentialities of the “cire perdue” or “lost wax” process in the breaking of volume and mass and to explore the possibilities of space in regard to free and open “organic” forms, and (2) to explore the versatility and flexibility of bronze as a material for such sculpture. This creative thesis is an outgrowth of “3 a.m.”, the artist’s first experience with bronze as a medium. Because of the dilemmas and rewards encountered in completing this perplex piece of sculpture the artist wished to continue his investigation. A motivating factor which helped determine the decision for further investigation was the act of departing from the traditional use of bronze. Throughout the past most cast bronze emphasized solid mass using volume as an expression of space. The sculpture making up this thesis achieves an immense amount of volume though its forms are broken and open creating space that is nothing but one continuous depth. Most constructivists are not castors and in working with complex forms choose materials they can manage such as steel, wood and plastics. However, because of the writer’s acute interest in the field of casting he was determined to succeed in casting such intricate and complicated forms. Because of the involved “gating system” necessary for such casting most commercial foundries would refuse service. Thus, it seems necessary that the constructivist sculptor, whose interest lies in the “lost wax” process, administer his own setting. The technical knowledge required in the casting of such sculpture is vast and involved, hence, each piece took considerable study and effort in striving for perfection. However, such study did not take place until the sculpture had been completed in the wax form. The facilities for “burn out” and the size of the foundry were the primary limitations in this search. The forms included in this creative thesis originated through preliminary thinking and sketching which resulted in a basic idea on paper or a mental image. Then shapes of wax were pre-cut, joined together and built up one piece at a time. Because of the artist’s individuality and his response to such a sketch or mental image, the piece itself, became the building blocks which determined the form and brought about the expected deviation from the original idea. As stated previously, there were no restriction, with the exception of largeness, allowing absolute concentration on the search for unique form. Only two pieces deviate from the process described above. The relief “Mother and Child” was first modeled in clay and “Bronze Head”, although created directly in wax, was built up through the use of the “pinch method”. Throughout the whole of the thesis there is an obvious personal preference for powerful and intense rectangular and square forms. This became a conscious preference in the artist’s search for personal expression. Through the use of several chemicals the investigator has experimented with the patination of different bronzed throughout this thesis. Realizing that bronze does possess a tonality of its own, the artist, because of his consciousness of color, felt that such patinas were an asset in the enhancement of the sculpture. Such experimentation also served to explore certain curiosities concerning patinas in conjunction with bronze. Upon the completion of this study it is felt that the build-up or constructive method, through the use of the “cire perdue” process, is more appropriate to this artist’s creative personality than any other approach or medium in sculpture as it imposes less limitation upon his personal expression. Regarding bronze, it is sensitive; it has an immense amount of versatility, flexibility and fluidity. The versatility of bronze appears in the surfaces that can be achieved. These may be smooth and flowing, with sharp clear edges, or they may accurately record the traces of the sculptor’s fingers on the pliable wax. Any surface treatment that is possible in clay or wax may be preserved in bronze. Above all bronze is a metal and has a high tensile strength making it possible to open it up, extend members or forms freely in any direction and preserve in relatively permanent form any shape and texture. These deductions, along with the education and the excitement of the casting process are among the reasons why the artist chose bronze for his constructions rather than steel, wood or plastic. Through this process the artist feels that he has “found himself” for the first time and that the forms in this thesis are truly unique expressions of himself

The effects of energetic proton bombardment on polymeric materials: Experimental studies and degradation models

This report describes 3 MeV proton bombardment experiments on several polymeric materials of interest to NASA carried out on the Tandem Van De Graff Accelerator at the California Institute of Technology's Kellogg Radiation Laboratory. Model aromatic and aliphatic polymers such as poly(1-vinyl naphthalene) and poly(methyl methacrylate), as well as polymers for near term space applications such as Kapton, Epoxy and Polysulfone, have been included in this study. Chemical and physical characterization of the damage products have been carried out in order to develop a model of the interaction of these polymers with the incident proton beam. The proton bombardment methodology developed at the Jet Propulsion Laboratory and reported here is part of an ongoing study on the effects of space radiation on polymeric materials. The report is intended to provide an overview of the mechanistic, as well as the technical and experimental, issues involved in such work rather than to serve as an exhaustive description of all the results

Enhancing and visualising data on soils, land use and the environment.

End of Project ReportA computer based system was developed to produce new information, charts and map data on soils, environment and land use for environmental decision support. The process involved manipulation of data in tabular and electronic map form by combining features from digitised maps and tables to develop an information system of linked and harmonised data. This report reviews and illustrates the findings with outputs in the form of maps and tables. Maps presenting sheep census information for the years 1970- 1991 show greatly increased livestock densities, in the latter years. These changes mainly occurred in the (i) traditional drystock areas of the midlands (ii) south east arable areas and (iii) south east Connacht dry stock/sheep areas and reflect economic and structural changes arising out of Government policy and membership of the EU. Maps depicting the temporal changes in dairy livestock densities were not so dramatic; however the structural change is particularly reflected in the reduction of dairying in the Connacht/Midlands regions. The introduction of milk quotas in the 1980's accelerated the changes which had been taking place since the early 1970's. In comparison to dairy cows, the increased concentration of drystock seems to be more widely spread. High concentrations of drystock occurred in the east midlands in 1970. By 1980, the high concentration of dry cattle had spread to North and South Midlands. The density of cattle increased further in Leinster and Munster areas by 1991. In Connaught, where sheep numbers had increased markedly between 1970 and 1991, cattle numbers remained relatively static. The digitisation of detailed soil survey maps was undertaken in this project and a new soil survey map of the Lough Derg Catchment was produced using Great Soil Groups as the mapping unit. This map is included in the report.European Union Structural Funds (EAGGF