5,720 research outputs found
Vacuum-stripped silicone binder for thermal-control paint
Silicone elastomer is placed in evacuating system, heated to 160 C and held at this temperature for 24 hours. Elastomer is then cooled to room temperature in vacuum, producing upgraded, low outgassing polymer of increased molecular weight
Study of in-situ degradation of thermal control surfaces
Experimental technique used in study of damage mechanism to semiconductor pigments exposed to ultraviolet radiation can be adapted for investigations of surface chemistry and may be used analytically to determine contamination
Development of space stable thermal control coatings for use on large space vehicles
The development of a large scale manufacturing method for the production of a stable zinc orthotitanate pigment by means of an oxalate co-precipitation method is examined. Pigments were prepared at various temperatures, and major emphasis was placed on the determination of the important parameters of post-precipitation firing and treatment. A large-scale process for the modification of a glass resin binder was developed and paints were formulated using the binder
Development of space-stable thermal-control coatings Triannual report, 1 Jan. - 30 Apr. 1970
Development and performance of solar wind simulation facility for studying thermal-control coating
Investigation of environmental effects on coatings for thermal control
Accomplishments made during study of coatings are reported. Development of structure/property theory for selecting most appropriate pigments for space vehicle paints is discussed along with improvements made in zinc-oxide pigmented potassium silicate paint
Applications of percolation theory to fungal spread with synergy
There is increasing interest in the use of the percolation paradigm to analyze and predict the progress of disease spreading in spatially-structured populations of animals and plants. The wider utility of the approach has been limited, however, by several restrictive assumptions, foremost of which is a strict requirement for simple nearest-neighbour transmission, in which the disease history of an individual is in uenced only by that of its neighbours. In a recent paper the percolation paradigm has been generalised to incorporate synergistic interactions in host infectivity and susceptibility and the impact of these interactions on the invasive dynamics of an epidemic has been demonstrated. In the current paper we elicit evidence that such synergistic interactions may underlie transmission dynamics in real-world systems by rst formulating a model for the spread of a ubiquitous parasitic and saprotrophic fungus through replicated populations of nutrient sites and subsequently tting and testing the model using data from experimental microcosms. Using Bayesian computational methods for model tting, we demonstrate that synergistic interactions are necessary to explain the dynamics observed in the replicate experiments. The broader implications of this work in identifying disease control strategies that de ect epidemics from invasive to non-invasive regimes are discussed
Stable White Coatings
In a previous research program for the Jet Propulsion- Laboratory, extensive studies led to the development and specifications of three zinc oxide-pigmented thermal-control coatings. The principal objectives of this program are: improvement of the three paints (as engineering materials), determination of the validity of our accelerated space-simulation testing, and continuation of the zinc oxide photolysis studies begun in the preceding program. Specific tasks that are discussed include: improvement of potassium silicate coatings as engineering materials and elucidation of their storage and handling problems; improvement of methyl silicone coatings as engineering materials; studies of zinc oxide photolysis to establish reasons for the observed stability of zinc oxide; and determination of space-simulation parameters such as long-term stability (to 8000 ESH), effect of coating surface temperature on the rate of degradation, and validity of accelerated testing (by reciprocity and wavelength dependency studies)
Electrically Conductive Paints for Satellites
A program was conducted to develop and test electrically conductive paint coatings for spacecraft. A wide variety of organic and inorganic coatings were formulated using conductive binders, conductive pigments, and similar approaches. Z-93, IITRI's standard specification inorganic thermal control coating, exhibits good electrical properties and is a very space-stable coating system. Several coatings based on a conductive pigment (antimony-doped tin oxide) in silicone and silicate binders offer considerable promise. Paint systems using commercially available conductive polymers also appear to be of interest, but will require substantial development. Evaluations were made based on electrical conductivity, paint physical properties, and the stability of spectral reflectance in space environment testing
Development of space-stable thermal-control coatings /paints with low solar absorptance/ emittance ratios/ triannual report, 20 jun. - 20 oct. 1964
Development of space stable thermal control coating
Betting and Belief: Prediction Markets and Attribution of Climate Change
Despite much scientific evidence, a large fraction of the American public
doubts that greenhouse gases are causing global warming. We present a
simulation model as a computational test-bed for climate prediction markets.
Traders adapt their beliefs about future temperatures based on the profits of
other traders in their social network. We simulate two alternative climate
futures, in which global temperatures are primarily driven either by carbon
dioxide or by solar irradiance. These represent, respectively, the scientific
consensus and a hypothesis advanced by prominent skeptics. We conduct
sensitivity analyses to determine how a variety of factors describing both the
market and the physical climate may affect traders' beliefs about the cause of
global climate change. Market participation causes most traders to converge
quickly toward believing the "true" climate model, suggesting that a climate
market could be useful for building public consensus.Comment: All code and data for the model is available at
http://johnjnay.com/predMarket/. Forthcoming in Proceedings of the 2016
Winter Simulation Conference. IEEE Pres
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