Lower Bound for Convex Hull Area and Universal Cover Problems

In this paper, we provide a lower bound for an area of the convex hull of points and a rectangle in a plane. We then apply this estimate to establish a lower bound for a universal cover problem. We showed that a convex universal cover for a unit length curve has area at least 0.232239. In addition, we show that a convex universal cover for a unit closed curve has area at least 0.0879873.Comment: 12 pages, 9 figure

Required technologies for a lunar optical UV-IR synthesis array

A Lunar Optical UV-IR Synthesis Array (LOUISA) proposed to take advantage of the characteristics of the lunar environment requires appropriate advances in technology. These technologies are in the areas of contamination/interference control, test and evaluation, manufacturing, construction, autonomous operations and maintenance, power and heating/cooling, stable precision structures, optics, parabolic antennas, and communications/control. LOUISA needs to be engineered to operate for long periods with minimal intervention by humans or robots. What is essential for LOUISA operation is enforcement of a systems engineering approach that makes compatible all lunar operations associated with habitation, resource development, and science

Engineering, construction, and operations in space

The century-old Mond process for carbonyl extraction of metals from ore shows great promise as an efficient low energy scheme for producing high-purity Fe, Ni, Cr, Mn, and Co from lunar or asteroidal feedstocks. Scenarios for winning oxygen from the lunar regolith can be enhanced by carbonyl processing of the metallic alloy by-products of such operations. The native metal content of asteroidal regoliths is even more suitable to carbonyl processing. High-purity, corrosion resistant Fe and Ni can be extracted from asteroidial feedstocks along with a Co-rich residue containing 0.5 percent platinum-group metals. The resulting gaseous metal carbonyl can produce a variety of end products using efficient vapor forming techniques

Environmental effects on lunar astronomical observatories

The Moon offers a stable platform with excellent seeing conditions for astronomical observations. Some troublesome aspects of the lunar environment will need to be overcome to realize the full potential of the Moon as an observatory site. Mitigation of negative effects of vacuum, thermal radiation, dust, and micrometeorite impact is feasible with careful engineering and operational planning. Shields against impact, dust, and solar radiation need to be developed. Means of restoring degraded surfaces are probably essential for optical and thermal control surfaces deployed in long-lifetime lunar facilities. Precursor missions should be planned to validate and enhance the understanding of the lunar environment (e.g., dust behavior without and with human presence) and to determine environmental effects on surfaces and components. Precursor missions should generate data useful in establishing keepout zones around observatory facilities where rocket launches and landings, mining, and vehicular traffic could be detrimental to observatory operation

Environmental effects on an optical-UV-IR synthesis array

The Moon offers a stable platform with excellent seeing conditions for the Lunar Optical-UV-IR Synthesis Array (LOUISA). Some troublesome aspects of the lunar environment will need to be overcome to realize the full potential of the Moon as an observatory site. Mitigation of negative effects of vacuum, thermal radiation, dust, and micrometeorite impact is feasible with careful engineering and operational planning. Shields against impact, dust, and solar radiation need to be developed. Means of restoring degraded surfaces are probably essential for optical and thermal control surfaces deployed in long-lifetime lunar facilities. Precursor missions should be planned to validate and enhance the understanding of the lunar environment (e.g., dust behavior without and with human presence and to determine environmental effects on surfaces and components. Precursor missions should generate data useful in establishing keepout zones around observatory facilities while rocket launches and landings, mining, and vehicular traffic could be detrimental to observatory operation

The Aquatic Biota and Groundwater Quality of Springs in the Lincoln Hills, Wisconsin Driftless, and Northern till Plains Sections of Illinois

ID: 8307INHS Technical Report prepared for Environmental Protection Trust Fund Commission and Illinois Department of Natural Resources Division of Energy and Environmental AssessmentU of I OnlyRestriction applied due to concern over geolocation information of springs on private property

SUPPLY RESPONSE TO TECHNOLOGICAL CHANGE AND REGULATION: THE CASE OF MECHANICALLY DEBONED POULTRY

Research and Development/Tech Change/Emerging Technologies,

Liquid metal cooled fast reactors

Fast spectrum reactors offer the capability for a better utilization of uranium resources. They are in principle capable to produce (“breed”) but also to transmute (“burn”) fissile materials either by means in a critical or in case of lead alloys even in a sub-critical configuration coupled with an accelerator (ADS).. Associated with the fast spectrum, they require not only a different core design but also many other technological solutions to establish a “safe reactor configuration”. Herein, especially sodium and lead (-alloy) facilitate the option to realize a compact and simple reactor design. While lead in contrast to sodium exhibits a higher neutronic efficiency associated with some often advantageous considered safety coefficients sodium cooled reactors proofed already long term operational experience and material compatibility. Irrespective of the liquid metal reactor concept chosen, liquid metals as coolant formulate new challenges with respect to thermal-hydraulics, material choice, design and system dynamics. Furthermore, the safety demonstration demands a broad validation/verification and in some cases even a modification of presently availalble physical models and technological solutions for a reliable monitoring and long term operation. After a short introduction into different kinds of some liquid metal reactor options currently developed within international programs the presentation formulates the major challenges related to the use of liquid metals addressing the thermal hydraulics and adapted instrumentation, some material issues and examples for a reliable component design. Herein, the progress attained in the recent years is shown and issues still open are elaborated. The research conducted in the frame of European R&D programs on sodium fast reactors as well as lead and LBE reactors and ADS impacted significantly their design and their operational safety. For some selected examples the safety behaviour of typical incidents in reactor operation are discussed and open issues are addressed

Nutrient limitation in the Chesapeake Bay : nutrient bioassays in the Virginia Bay system: final report

Nutrient enrichment bioassays were conducted on water samples collected from six stations in the Virginia portion of the Chesapeake Bay system on a monthly basis over a year. Two stations were located in the tidal freshwater portions of the Rappahannock and James Rivers, at the mouths of these rivers and in the mainstem of the Bay. The purpose of the experiments was to determine the spatial and temporal pattern of nutrient limitation of phytoplankton growth