An evaluation of two flat-black silicone paints for space application

Tests were conducted on two flat-black silicone paints suggested for space applications to determine their optical, electrical, and mechanical properties. Three different types of substrate materials were chosen for these paint tests; the application of the paints onto the primed substrates was carried out by spray coating. The adhesion properties were verified by thermal shock and sudden immersion into liquid nitrogen. A controlled thermal vacuum tests was also carried out by varying the temperature of the paint from -100 to 225 C. The measured optical properties included normal and hemispherical emittance, and solar absorption/reflectance. A simultaneous exposure to low-energy proton/UV irradiation in vacuum, and high-energy proton/electron irradiation was carried out. Additional tests of the paints are described

ADJUSTING FARM PRODUCTION THROUGH A GRASS AND LIVESTOCK PROGRAM: A NEW LOOK AT AGRICULTURAL PROGRAMS

Production Economics,

The development of a new sport-specific classification of coping and a meta-analysis of the relationship between different coping strategies and moderators on sporting outcomes

There is an ever growing coping and sports performance literature, with researchers using many different methods to assess performance and different classifications of coping. As such, it makes it difficult to compare studies and therefore identify how coping is related to performance. Furthermore, there are no quantitative syntheses of the results from these studies. A quantitative synthesis would facilitate a more comprehensive understanding of how coping is associated with athletic performance. In order to accurately compare studies, our first aim was to develop a new coping classification that would make this possible. Firstly, we reviewed the strengths and limitations of the different coping classifications and then identified the commonalities and differences between such classifications. We opted for a three-factor classification of coping, because the evidence suggests that a three-factor classification provides a superior model fit to two-factor approaches. Our new classification of coping was based on an existing model from the developmental literature, which received an excellent model fit. We made some adaptations, however, as our classification was intended for an athletic population. As such, we classified coping as mastery (i.e., controlling the situation and eliminating the stressor), internal regulation (i.e., managing internal stress responses), or goal withdrawal (i.e., ceasing efforts towards goal attainment). Undertaking a meta-analysis, our second aim was to identify which coping strategies correlated with sports performance and whether this relationship varied according to moderator variables. Articles were sourced from online electronic databases and manual journal searches. PRISMA guidelines were used to search, select, and synthesize relevant studies. Random effects meta-analyses were performed to identify associations between coping classification and sport performance. Q, I2, and R2 values assessed heterogeneity. Eighteen published investigations, including 3900 participants and incorporating fifty-nine correlations, indicated an overall positive effect for mastery coping, a negligible negative effect for internal regulation coping, and a negative effect for goal withdrawal strategies. The findings of this meta-analysis could be used by sports practitioners to help them deliver effective coping interventions. In order to maximize performance, practitioners could encourage the use of mastery coping, but advise their athletes not to use goal withdrawal strategies

Estimating abundance of Galliformes: tools and application

A large number of techniques are available for assessing populations of vertebrates. However, application of many of those techniques to Galliformes is hampered by a variety of constraints. These problems are often magnified by poor understanding of the biology of many species of concern, and an absence of valid estimates of abundance and demographic parameters. Researchers interested in developing estimates of Galliformes populations must address a number of key issues before collecting field data, to avoid biases in the resulting population estimates. General guidance exists for the identification of appropriate population estimation techniques, and a dichotomous key has been developed for abundance estimation of other vertebrates, such as mammals. First, we review some of the basic principles of abundance estimation, with the goal of identifying sources of bias, and avoiding these in field surveys. We then develop specific guidelines for Galliformes, and a key to abundance estimation for field researchers. Based on our knowledge of the general biology of Galliformes, the most applicable techniques for estimating abundance are based on variations of distance sampling techniques, mark-resighting techniques, and removal techniques. Use of indices should be considered only when more quantitative analyses are logistically or biologically impossible. However, their use can be made more valuable by employing double sampling or other methods that directly link indices to unbiased estimates of abundance

Four space application material coatings on the Long-Duration Exposure Facility (LDEF)

Four material coatings of different thicknesses were flown on the LDEF to determine their ability to perform in the harsh space environment. The coatings, located in the ram direction of the spacecraft, were exposed for 10 months to the low-Earth orbit (LEO) environments experienced by the LDEF at an orbit of 260 nautical miles. They consisted of indium oxide (In2O3), silicon oxide (SiO(x)), clear RTV silicone, and silicone with silicate-treated zinc oxide (ZnO). These coatings were flown to assess their behavior when exposed to atomic oxygen and to confirm their good radiative properties, stability, electrical conductivity, and resistance to UV exposure. The flown samples were checked and compared with the reference unflown samples using high-magnification optical inspection, ESCA analysis, weight changes, and dimensional changes. These comparisons indicated the following. The 1000 A SiO(x) coating eroded uniformly, with minor changes in its radiative properties. The 100 A In2O3 coating eroded completely down to the Kapton backing, with resultant losses of reflectance. The RTV-615 showed erosion, with carbon (C) content losses, while the Si remained constant, with a doubling of the oxygen (O) concentration. The RTV-615 silicone with K2SiO3-treated ZnO changed from flat to glossy white in appearance. It lost C, was etched, and increased its O content. The upper layers showed no remaining Zn or K. Losses of reflectance occurred within certain wavelength bands. It was not possible to evaluate the experimental oxygen reaction rate using the calculated atomic oxygen fluence of 2.6 x 10(exp 20) atoms/cm(exp 2) for the exposure of these coatings during the flight. The bakeout of the coatings was not carried out prior to the flight. Hence, the coating weight and dimensional losses included losses by outgassing products

Four space application material coatings on the long-duration exposure flight (LDEF)

Four material coatings of different thickness were flown on the LDEF to determine their ability to perform in the harsh space environment. The coatings, located in the ram direction of the spacecraft, were exposed for 10 months to the low-Earth orbit (LEO) environment experienced by the LDEF at an orbit of 260 nautical miles. They consisted of indium oxide (In2O3), silicon oxide (SiO(x)), clear RTV silicone, and silicone with silicate-treated zinc oxide (ZnO). These coatings were flown to assess their behavior when exposed to atomic oxygen and to confirm their good radiative properties, stability, electrical conductivity, and resistance to UV exposure. The flown samples were checked and compared with the reference unflown samples using high-magnification optical inspection, ESCA analysis, weight changes and dimensional changes. These comparisons indicated the following: The 1000 A SiO(x) coating eroded uniformly, with minor changes in its radiative properties. The 100 A of In2O3 coating eroded completely down to the Kapton backing, with resultant losses of reflectance. The RTV-615 showed erosion, with carbon (C) content losses, while the Si remained constant, with a doubling of the oxygen (O) concentration. The RTV-615 silicone with K2SiO3-treated ZnO changed from flat to glossy white in appearance. It lost C, was etched, and increased its O content. The upper layers showed no remaining Zn or K. Losses of reflectance occurred within certain wavelength bands. It was not possible to evaluate the experimental oxygen reaction rate using the calculated atomic oxygen fluence of 2.6 x 10(exp 20) atoms/cm(exp 2) for the exposure of these coatings during the flight. The bakeout of the coatings was not carried out prior to the flight. Hence, the coating weight and dimensional losses included losses by outgassing products

Comparison of Northern Bobwhite Chick Fecal and Crop Analyses

Impacts of modem agriculture on gamebird brood ecology have been studied in a number of species. One common factor cited has been the decline in available invertebrate food available to foraging chicks. In the United Kingdom, assessment of chick diet has been accomplished mainly through fecal analysis of wild chicks, whereas in North America crop analysis of human-imprinted chicks has become a commonly applied technique. We compared results of both techniques on groups of human-imprinted northern bobwhite (Colinus virginianus) chicks to determine if these different techniques provide similar results. Chicks were allowed to forage in groups of 6-8 in cotton fields with various cover crops. We euthanized half the chicks for crop analysis and isolated the other half of the chicks for 12 hours to collect feces. We found a positive relationship between total number of invertebrates/chick in crops and feces (P = 0.01, R2 = 0.51). However, among important chick-food Orders the relationship varied greatly: Coleoptera (P = 0.10, R2 = 0.34), Homoptera (P \u3c 0.001, R2 = 0.41), and Hymenoptera (P = 0.81, R2 = 0.05). Our results suggest that there is a positive relationship between the 2 techniques, but that composition of the diet relative to what foods might be available in a particular site could be biased. We suggest more detailed research on technique development and standardization of techniques for assessing this important component of bobwhite life history

Striving for safety: communicating and deciding in sociotechnical systems

How do communications and decisions impact the safety of sociotechnical systems? This paper frames this question in the context of a dynamic system of nested sub-systems. Communications are related to the construct of observability (i.e. how components integrate information to assess the state with respect to local and global constraints). Decisions are related to the construct of controllability (i.e. how component sub-systems act to meet local and global safety goals). The safety dynamics of sociotechnical systems are evaluated as a function of the coupling between observability and controllability across multiple closed-loop components. Two very different domains (nuclear power and the limited service food industry) provide examples to illustrate how this framework might be applied. While the dynamical systems framework does not offer simple prescriptions for achieving safety, it does provide guides for exploring specific systems to consider the potential fit between organisational structures and work demands, and for generalising across different systems regarding how safety can be managed