Resin additive improves performance of high-temperature hydrocarbon lubricants

Paraffinic resins, in high temperature applications, improve strength of thin lubricant film in Hertzian contacts even though they do not increase bulk oil viscosity. Use of resin circumvents corrosivity and high volatility problems inherent with many chemical additives

Liquid lubricants for advanced aircraft engines

An overview of liquid lubricants for use in current and projected high performance turbojet engines is discussed. Chemical and physical properties are reviewed with special emphasis placed on the oxidation and thermal stability requirements imposed upon the lubrication system. A brief history is given of the development of turbine engine lubricants which led to the present day synthetic oils with their inherent modification advantages. The status and state of development of some eleven candidate classes of fluids for use in advanced turbine engines are discussed. Published examples of fundamental studies to obtain a better understanding of the chemistry involved in fluid degradation are reviewed. Alternatives to high temperature fluid development are described. The importance of continuing work on improving current high temperature lubricant candidates and encouraging development of new and improved fluid base stocks are discussed

High-temperature, long-life polyimide seals for hydraulic actuator rods

Two types of polyimide seals are developed for hydraulic actuator rod in low pressure second stage of two-stage configuration. Each seal melts test objectives of twenty million cycles of operation at 534 K. Analytical and experimental study results are discussed. Potential applications are given

Simple Computational Methods for Measuring the Difference of Empirical Distributions: Application to Internal and External Scope Tests in Contingent Valuation

This paper develops a statistically unbiased and simple method for measuring the difference of independent empirical distributions estimated by bootstrapping or other simulation approaches. This complete combinatorial method is compared with other unbiased and biased methods that have been suggested in the literature, first in Monte Carlo simulations and then in a field test of external and internal scope testing in contingent valuation. Tradeoffs between methods are discussed. When the empirical distributions are not independent a straightforward difference test is suggested.Research Methods/ Statistical Methods,

Using Random Parameters to Account for Heterogeneous Preferences in Contingent Valuation of Public Open Space

To test for preference heterogeneity in dichotomous choice contingent valuation responses, a random parameter logit (RPL) specification is used in this analysis. The RPL model confirms heterogeneity in respondents' preferences for protection of public open space, as reflected in statistically significant standard deviations of the normally distributed random parameters. Results show that while the majority of respondents indicate a positive willingness to pay (WTP), a minority of those surveyed report a negative WTP. Some of this variation in tastes remains even after individual characteristics and attitudinal variables are included in the model.contingent valuation, open space, random parameter logit, willingness to pay, Land Economics/Use,

Postcard: A.H.T.A. Parade, Peabody, Kansas

This black and white photographic postcard features a parade on the main street at Peabody, Kansas. Buildings are on the left with people lining the sidewalks. A girl on a horse, a man in a wagon and two boys on bicycles are in the foreground of the parade. Written text is at the bottom of the card. Handwriting is on the back of the card.https://scholars.fhsu.edu/tj_postcards/2240/thumbnail.jp

Recent Advances of the Forest in Iowa

At the time of settlement Iowa was definitely a prairie state with less than 20 per cent of its area covered by timber. Such a distribution of vegetation, coupled with short time observations, has led to the general assumption that prairie is the climax vegetation of the state. The writers have recently (7) assembled evidence that the present climate of Iowa is capable of supporting a forest climax. Prairie is therefore a subclimax associes maintained by its early establishment and by the marginal nature of the climate, but particularly by a combination of soil factors favoring prairie over woodland. The establishment of our classification depends upon evidence that forest is not only able to survive in Iowa, but that it has been able to invade the prairie at an appreciable rate under undisturbed conditions. Additional evidence of the spread of forest in Iowa, both after and before settlement, is presented here