Characterization of wear debris generated in accelerated rolling-element fatigue tests

A ferrographic analysis was used to determine the types and quantities of wear debris generated during accelerated rolling contact fatigue tests. The five-ball rolling contact fatigue tester was used. Ball specimens were made of a corrosion resistant, high-temperature bearing steel. The lubricant was a superrefined naphthenic mineral oil. Conditions included a maximum Hertz stress of 5.52 10 to the 9th power Pa and a shaft speed of 10,000 rpm. Four types of wear debris were observed: (1) normal rubbing wear particles, (2) fatigue microspall particles, (3) spheres, and (4) friction polymer deposits. The characterization of wear debris as a function of time was of limited use in predicting fatigue failures in these accelerated tests

Ferrographic analysis of wear debris generated in accelerated rolling element fatigue tests

The types and quantities of wear particles generated during accelerated ball rolling contact fatigue tests were determined. Ball specimens were made of AMS 5749, a corrosion resistant, high-temperature bearing steel. The lubricant was a super-refined naphthenic mineral oil. Conditions included a maximum Hertz stress of 5.215 times 10 to the 9th power Pa and a shaft speed of 10,000 rpm. Four types of wear particles were observed; normal rubbing wear particles, fatigue spall particles, spheres, and friction polymer

Fiber-modified polyurethane foam for ballistic protection

Closed-cell, semirigid, fiber-loaded, self-extinguishing polyurethane foam material fills voids around fuel cells in aircraft. Material prevents leakage of fuel and spreading of fire in case of ballistic incendiary impact. It also protects fuel cell in case of exterior fire

Monitoring of solar far ultraviolet radiation from the OSO-5 satellite

A spectrophotometer for monitoring the solar EUV in three broad wavelength bands is described. The kind of data obtained, along with sources of error, are presented. The content of the tape library which contains the data is outlined. The scientific results are discussed. These include the following: solar flares in the EUV, solar eclipse observations in the EUV, SFD's and relationship to solar flares, and the application of satellite sunrise and sunset data for the study of model upper atmospheres for the earth

Advanced supersonic technology fuel tank sealants

Status of the fuel tank simulation and YF-12A flight tests utilizing a fluorosilicone sealant is described. New elastomer sealant development is detailed, and comparisons of high and low temperature characteristics are made to baseline fluorosilicone sealants

The Impact of the PROGRESA/Oportunidades Conditional Cash Transfer Program on Health and Related Outcomes for the Aging in Mexico

Conditional cash transfer (CCT) programs link public transfers to human capital investment in hopes of alleviating current poverty and reducing its intergenerational transmission. Whereas nearly all studies of their impacts have focused on youth, these CCT programs may also have an impact on aging adults, by increasing household resources or inducing changes in allocations of time of various household members, that may be of substantial interest, particularly given the rapid aging of most populations. This paper contributes to this under-researched area by examining health and work impacts on the aging for the best known and most influential of these programs, the Mexican PROGRESA/Oportunidades program. For a number of health indicators, the program appears to significantly improve health, with impacts that are larger with a greater time receiving the program. However, most of these health impacts are concentrated on women.conditional cash transfers, aging, health, Mexico

Polyimide fiber-glass composite resists high temperatures

Composites synthesized from bismaleimide have superior strength and oxidation resistance at elevated temperatures when compared with similar composites prepared with epoxy or silicon polymers of similar cost. Polyimide synthesis technique and processing method yield essentially void-free fiber-glass reinforced composites

Fire retardant foams developed to suppress fuel fires

Heat insulating polyurethane foam retards and suppresses fuel fires. Uniformly dispersed in the foam is a halogenated polymer capable of splitting off hydrogen halide upon heating and charring of the polyurethane

Maximizing Reproductive Efficiency in the Cow Herd

Maximum reproductive efficiency in a cow herd will not often be achieved accidentally. Every producer must set for himself a goal of the level of reproductive efficiency that he desires to achieve in his herd. A goal that I believe is realistic for South Dakota cattle producers is to have 95 to 100% of his cow herd calve every 12 months and wean a 500 to 600 pound calf. Whatever the goal is, it seldom will be achieved by chance alone. We can\u27t hope a group of heifers into reaching puberty by 14 months of age, we can\u27t hope 95% of our cows into conceiving in a 45-day period nor can we hope them into weaning 600 pound calves. These objectives can only be achieved by following a carefully planned management system