The feasibility of low-G grey solidification of nodular iron in the F-104 experimental furnace package

The rationale for low-g experiments with cast iron and the need for solidification in the grey form during these experiments are reviewed. The factors which determine whether an iron melt will solidify grey or white are discussed. Cooling rate versus microstructure was studied for a nodular iron candidate material for F-104 low-g solidification. The study determined that low-g grey solidification, using the present F-104 furnace system, of the nodular iron composition studied is not feasible. Specimen microstructure strongly suggested that the F-104 furnace's gas cooling system was causing excessive localized chill resulting in the nucleation of the unwanted iron carbide phase. A change is suggested, in the quench system design, that could possibly overcome this problem

Non-Market Valuation of Open Space and Other Amenities Associated with Retention of Lands in Agricultural Use

The most productive farmland in southcentral Alaska is currently under intense development pressure due to rapid population increases and consequential increases in demand for suburban housing. This study utilizes a contingent valuation iterative bidding game to estimate the willingness of Matanuska-Susitna Borough residents to pay to preserve open space and other historical/environmental amenities associated with farming activities. Determinants of consumer behavior are addressed as well as total benefits and costs of various posited development scenarios. This information may be useful to policymakers assessing actions designed to purchase development rights from Matanuska-Susitna farmers

A Rosetta Stone Relating Conventions In Photo-Meson Partial Wave Analyses

A new generation of complete experiments in pseudoscalar meson photo-production is being pursued at several laboratories. While new data are emerging, there is some confusion regarding definitions of asymmetries and the conventions used in partial wave analyses (PWA). We present expressions for constructing asymmetries as coordinate-system independent ratios of cross sections, along with the names used for these ratios by different PWA groups. (This update reflects a recent change in the definition of an asymmetry as used by one group.)Comment: v2: This update reflects a recent change in the definition of an asymmetry as used by one PWA group -see Table 1. v1: 4 pages. Contribution to the proceedings of the 8th International Workshop on the Physics of Excited Nucleons (NSTAR2011), Newport News, VA, USA, May 17-20, 201

Combined space environment on spacecraft engineering materials

Spacecraft structures and surface materials exposed to the space environment for extended periods, up to thirty years, have increased potential for damage from long term exposure to the combined space environment including solar ultraviolet radiation, electrons, and protons and orbiting space debris. The space environment in which the Space Station Freedom and other space platforms will orbit is truly a hostile environment. For example, the currently estimated integral fluence for electrons above 1 Mev at 2000 nautical miles is above 2 x 10(exp 10) electrons/cm(sup 2)/day and the proton integral fluence is above 1 x 10(exp 9) protons/cm(sup 2)/day. At the 200 - 400 nautical miles, which is more representative of the altitude which will provide the environment for the Space Station, each of these fluences will be proportionately less; however, the data indicates that the radiation environment will obviously have an effect on structural materials exposed to the environment for long durations. The effects of ultraviolet radiation, particularly in the vacuum ultraviolet (less than 200 nm wavelength) is more difficult to characterize at this time. Very little data is available in the literature which can be used for determining the life cycle of a material placed in space for extended durations of time. In order to obtain critical data for planning and designing of spacecraft systems, use of a small vacuum system at the Environmental Effects Facility at MSFC, which can be used for these purposes was used. A special effort was made to build up this capability during the course of this research effort and perform a variety of experiments on materials proposed for the Space Station. A description of the apparatus and the procedure devised to process potential spacecraft materials is included

Fiber pulling apparatus modification

A reduced gravity fiber pulling apparatus (FPA) was constructed in order to study the effects of gravity on glass fiber formation. The apparatus was specifically designed and built for use on NASA's KC-135 aircraft. Four flights have been completed to date during which E-glass fiber was successfully produced in simulated zero, high, and lunar gravity environments. In addition simulated lunar soil samples were tested for their fiber producing properties using the FPA

Test equipment data package for the KC-135 fiber pulling apparatus

The Fiber Pulling Apparatus (FPA) is a device designed to produce continuous glass fibers from simulated lunar soil, and to determine the effects of reduced gravity, specifically 1/6 g on fiber formation and resultant properties. Briefly, pre-melt simulated lunar soil will be placed in a pint crucible and heated to 1200 C or higher, up to a maximum temperature of 1400 C. At a given temperature, a quartz fiber will be immersed into the melt and then pulled through a chill block and wound onto a cylindrical bobbin using a servo motor control. A high resolution video camera will record the fiber as it is being pulled. This assembly wil be enclosed in Plexiglas. Before fiber pulling commences, the apparatus will be backfilled with dry nitrogen. A separate data acquisition system will support this apparatus. This system will contain a personal computer, video recorder, and monitor. Temperature, acceleration, winding speed, and video images will be controlled and recorded using the data acquisition system. Thus, the FPA will consist of two hardware packages, the fiber production assembly and the data acquisition rack. The primary objective of this test is to determine the effects of 1/6 g on the formation of continuous glass fiber made from simulated lunar soil. Baseline studies using the FPA on the ground will provide a reference for the 1/6 g studies. Of particular interest will be the effect of 1/6 g on the free fluid zone where the fiber exits the crucible. In the fiber spinning parlance this zone is known as the upper jet region, where the boundary slope is greater than one tenth. The properties of the resulting glass fiber will depend on the jet shape as well as distributions of velocity, temperature and tension within the jet. It is unknown at this time how 1/6 g will effect these parameters