6,619 research outputs found
The Installation and Operation of a Creep Testing Machine to Determine its Operating Characteristics
When designing any kind of structure or machine for high temperature operation, the engineer has to consider the effects of creep. In steam and gas turbines, for example, the rotor blades are subjected to high stresses by centrifugal force and to elevated temperatures by high pressure steam or hot gases. The combination of high stress and temperature causes a plastic deformation in the blades. This deformation, known as creep, occurs in all metals under the appropriate temperature and stress conditions, though some metals are more resistant to it than others. It is practically undesirable to employ a design so low that no creep will occur; therefore, it must be accounted for in the design of the structure. The creep of a material can be accurately measured in a testing machine, but creep tests cannot be conducted for a length of time corresponding to the life for which a part is usually designed. The rate at which a material creeps over a certain test period is determined in the creep test; and, by the use of empirical relationships, this creep rate can be employed to deduce what the creep will be at the end of a desired time interval. The purpose of this project was to install a creep-rate testing machine in the Mechanical Engineering Research Laboratory at South Dakota State College, and to determine its operating characteristics by conducting tests on a material with known creep properties
Trends in Education Philanthropy: Benchmarking 2023
This report offers insights into where and how funders are working, their evolving priorities and their role in supporting education innovation that benefits the nation's learners. The 15th anniversary report by Grantmakers for Education -- the first post pandemic -- is based on a survey of 142 education philanthropies. The survey results signal that the pandemic and attention to the ways in which systems disadvantage different communities have shifted the investments and concerns of education philanthropists.Education philanthropies are funding redesign and transformation in the U.S. education system, signaling a fundamental shift in approach.Education funders are very concerned about the politicization of education. Funder interest in supporting a "whole learner" approach is growing, as there is growing recognition that children without access to basic needs and emotional security will not thrive academically.With trust in government eroding, the role of philanthropy as it relates to education has never been more critical, but the impact of philanthropy depends on whether funders can critically examine their own practices
Ethics, Efficacy, and Decision-making in Animal Research
Few would disagree with the ethical contention that if cruelty to animals is not wrong, then nothing is wrong. In fact, it is not only wrong, but in most states in the us, it is a crime, a felony no less. And yet, intentionally inflicting pain and suffering upon animals, which meets Websterâs definition of cruelty, is routinely countenanced when vivisection (from the Latin vivi, to be alive, and secare, to cut) is performed under license for biomedical research. Deciding to embrace, or reject, or limit animal research demands our best ethical judgment; and it is complicated by factual disputes over the extent to which it benefits human health. Three issues combining facts and ethics need to be considered. First, to what extent does animal research deliver on its promise to improve human health? Second, if the goal of public investment (e.g., tax dollars spent by the National Institute of Health, nih) on animal research is to improve human health, are we getting sufficient return for the billions spent, or might the money be better directed towards human-based research or implementing healthcare interventions of proven efficacy? Third, since opinions about ends justifying means will vary, who should decide if animal research is ethically justified: the scientists who perform it or representatives of the public at large, who pay for it
New Ways of Paying for College: Should the Federal Government Help?
This historical perspective and creative \u27burden-sharing\u27 approach to financing a college education was presented at a conference in December 1988 at the Brookings Institution in Washington, D. C. Look for the article in New Ways of Paying for College, a book to be published in Fall, 1989, by ACE/MacMilla
Ethics, Efficacy, and Decision-making in Animal Research
Few would disagree with the ethical contention that if cruelty to animals is not wrong, then nothing is wrong. In fact, it is not only wrong, but in most states in the us, it is a crime, a felony no less. And yet, intentionally inflicting pain and suffering upon animals, which meets Websterâs definition of cruelty, is routinely countenanced when vivisection (from the Latin vivi, to be alive, and secare, to cut) is performed under license for biomedical research. Deciding to embrace, or reject, or limit animal research demands our best ethical judgment; and it is complicated by factual disputes over the extent to which it benefits human health. Three issues combining facts and ethics need to be considered. First, to what extent does animal research deliver on its promise to improve human health? Second, if the goal of public investment (e.g., tax dollars spent by the National Institute of Health, nih) on animal research is to improve human health, are we getting sufficient return for the billions spent, or might the money be better directed towards human-based research or implementing healthcare interventions of proven efficacy? Third, since opinions about ends justifying means will vary, who should decide if animal research is ethically justified: the scientists who perform it or representatives of the public at large, who pay for it
Analysis of millimetre-wave polarization diverse multiple-input multiple-output capacity
Millimetre-waves offer the possibility of wide bandwidth and consequently high data rate for wireless communications. For both uni- and dual-polarized systems, signals sent over a link may suffer severe degradation due to antenna misalignment. Orientation robustness may be enhanced by the use of mutual orthogonality in three dimensions. Multiple-input multiple-output polarization diversity offers a way of improving signal reception without the limitations associated with spatial diversity. Scattering effects often assist propagation through multipath. However, high path loss at millimetre-wave frequencies may limit any reception enhancement through scattering. We show that the inclusion of a third orthogonal dipole provides orientation robustness in this setting, as well as in a rich scattering environment, by means of a Rician fading channel model covering all orientations for a millimetre-wave, tri-orthogonal, half-wave dipole transmitter and receiver employing polarization diversity. Our simulation extends the analysis into three dimensions, fully exploiting individual sub-channel paths. In both the presence and absence of multipath effects, capacity is observed to be higher than that of a dual-polarized system over the majority of a field of view.Nicholas P. Lawrence, Brian W.-H.Ng, Hedley J. Hansen, and Derek Abbot
Market-Based Alternatives for Managing Congestion at New Yorkâs LaGuardia Airport
We summarize the results of a project that was motivated by the expiration of the âHigh Density Rule,â which defined the slot controls employed at New Yorkâs LaGuardia Airport for more than 30 years. The scope of the project included the analysis of several administrative measures, congestion pricing options and slot auctions. The research output includes a congestion pricing procedure and also the specification of a slot auction mechanism. The research results are based in part on two strategic simulations. These were multi-day events that included the participation of airport operators, most notably the Port Authority of New York and New Jersey, FAA and DOT executives, airline representatives and other members of the air transportation community. The first simulation placed participants in a stressful, high congestion future scenario and then allowed participants to react and problem solve under various administrative measures and congestion pricing options. The second simulation was a mock slot auction in which participants bid on LGA arrival and departure slots for fictitious airlines.Auctions, airport slot auctions, combinatorial auctions
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