Improved Two-Dimensional Kinetics (TDK) computer program

Fluid properties, the boundary layer module, and regenerative cooling are discussed. Chemistry, low density flow effects, test cases, input and output for TDK, and documentation are also discussed

Performance predictions for an SSME configuration with an enlarged throat

The Two Dimensional Kinetics (TDK) computer program that was recently developed for NASA was used to predict the performance of a Large Throat Configuration of the Space Shuttle Main Engine (SSME). Calculations indicate that the current design SSME contains a shock wave that is induced by the nozzle wall shape. In the Large Throat design an even stronger shock wave is predicted. Because of the presence of this shock wave, earlier performance predictions that have neglected shock wave effects have been questioned. The JANNAF thrust chamber performance prediction procedures given in a reference were applied. The analysis includes the effects of two dimensional reacting flow with a shock wave. The effects of the boundary layer with a regenatively cooled wall are also included. A Purdue computer program was used to compute axially symmetric supersonic nozzle flows with an induced shock, but is restricted to flows with a constant ratio of specific heats. Thus, the TDK program was also run with ths assumption and the results of the two programs were compared

Engineering and programming manual: Two-dimensional kinetic reference computer program (TDK)

The Two Dimensional Kinetics (TDK) computer program is a primary tool in applying the JANNAF liquid rocket thrust chamber performance prediction methodology. The development of a methodology that includes all aspects of rocket engine performance from analytical calculation to test measurements, that is physically accurate and consistent, and that serves as an industry and government reference is presented. Recent interest in rocket engines that operate at high expansion ratio, such as most Orbit Transfer Vehicle (OTV) engine designs, has required an extension of the analytical methods used by the TDK computer program. Thus, the version of TDK that is described in this manual is in many respects different from the 1973 version of the program. This new material reflects the new capabilities of the TDK computer program, the most important of which are described

Antenna servo control system characterization: Rate loop analysis for 34-m antenna at DSS 15

The elevation and azimuth servo rate loops at the 34-m High Efficiency Deep Space Station 15 (DSS 15) are described. Time and frequency response performance criteria were measured. The results are compared to theoretically deduced performance criteria. Unexpected anomalies in the frequency response are observed and identified

Attachment to tourism destinations: The role of memory and place attachment

The purpose of this study was to explore the role that autobiographical memory plays in explaining how people become attached to tourism destinations. Autobiographical memory is an innovative method adopted from psychology which comprises the personal recollections individuals have of experiences and events. Furthermore, place attachment is a long-standing concept in tourism that identifies the emotional connection people have with places. Through an on-site visitor survey and a mail-back follow-up, 2,216 mail-back surveys were given to Yellowstone National Park visitors with 802 completed surveys (36 percent response rate). A structural equation model between autobiographical memory and place attachment indicated a significant, positive relationship between the strength of a visitor’s autobiographical memory salience and their level of place attachment. Thus, this model can be used forward in tourism research to identify how travelers form an attachment to the destination

Consensus Building in Native American Outreach: A Process Plan for Consensus Building in the Evaluation of the NSGC Native American Outreach Program

The NASA Nebraska Space Grant (NSGC) & EPSCoR Programs at the University of Nebraska at Omaha have embarked on a unique educational journey. This journey, known as the Native American Outreach program has been a highly successful endeavor since its inception five years ago. The Native American Outreach Program’s main objective is to make Native American students more competitive in mathematics and science. This program is the most comprehensive Native American program of any state and has allowed for a variety of activities to take place including: regional and national presentations; interfacing between schools; and formulating administrative leadership conferences. In order to continually provide effective support to Nebraska’s Native American community, NSGC & EPSCoR sought an evaluation technique for the Native American Outreach Program. To execute such an evaluation, the NSGC organized the first Nebraska Aeronautics Education Summit (NAES) Meeting. The diverse group of educators, researchers, and practitioners present at the summit provided a unique opportunity to gather information by employing a focus group research technique. This opportunity was not only beneficial to the Native American Outreach program by assessing its strengths and weaknesses, but also to those who participated in the study by providing them with a worthwhile learning experience. The results and recommendations acquired and included in this document were indeed remarkable. The utilization of the summit participants’ recommendations and innovative future plans will ensure continued shared success between NSGC & EPSCoR and the Nebraska Native American community

A Process Plan for Consensus Building in the Evaluation of NSGC & EPSCoR Native American Outreach Program

The NASA Nebraska Space Grant (NSGC) & EPSCoR Programs at the University of Nebraska at Omaha have embarked on a unique educational journey known as the Nebraska Native American Outreach program (NNAOP). The NNAOP’s main objective is to encourage and motivate Native American students to be more competitive in mathematics and science. This program has allowed for a variety of educational and public outreach activities to take place. However, in order to continually provide effective support to Nebraska’s Native American community, NSGC & EPSCoR sought an evaluation technique for the NNAOP. To execute such an evaluation, NSGC organized the first Nebraska Aeronautics Education Summit (NAES) Meeting. This diverse group of educators, researchers, and practitioners provided a unique opportunity to gather the evaluative information. The utilization of the summit participants’ recommendations and innovative future plans will ensure continued shared success between NSGC & EPSCoR and the Nebraska Native American community

Racial Differences in Inequality Aversion: Evidence from Real World Respondents in the Ultimatum Game

The distinct historical and cultural experiences of American blacks and whites may influence whether members of those groups perceive a particular exchange as fair. We investigate racial differences in fairness standards using preferences for equal treatment in the ultimatum game, where responders choose to allow a proposed division of a monetary amount or to block it. Although previous research has studied group differences in the ultimatum game, no study has been able to examine these across races in America. We use a sample of over 1600 blacks and whites drawn from the universe of registered voters in three states and merged with information on neighborhood income and racial composition. We experimentally vary proposed divisions as well as the implied race of the ultimatum game proposer. We find no overall racial differences in acceptance rates or aversion to unequal divisions. However, we uncover racial differences in the response to pecuniary returns conditional on inequality of the division. This is driven by the lowest income group in our sample, which represents the 10th percentile of the black income distribution. The racial differences are robust across gender and age groups. We also find that blacks are more sensitive to unfair proposals from other blacks.

Geographical gradients in diet affect population dynamics of Canada lynx

Geographical gradients in the stability of cyclic populations of herbivores and their predators may relate to the degree of specialization of predators. However, such changes are usually associated with transition from specialist to generalist predator species, rather than from geographical variation in dietary breadth of specialist predators. Canada lynx (Lynx canadensis) and snowshoe hare (Lepus americanus) populations undergo cyclic. fluctuations in northern parts of their range, but cycles are either greatly attenuated or lost altogether in the southern boreal forest where prey diversity is higher. We tested the influence of prey specialization on population cycles by measuring the stable carbon and nitrogen isotope ratios in lynx and their prey, estimating the contribution of hares to lynx diet across their range, and correlating this degree of specialization to the strength of their population cycles. Hares dominated the lynx diet across their range, but specialization on hares decreased in southern and western populations. The degree of specialization correlated with cyclic signal strength indicated by spectral analysis of lynx harvest data, but overall variability of lynx harvest (the standard deviation of natural-log-transformed harvest numbers) did not change significantly with dietary specialization. Thus, as alternative prey became more important in the lynx diet, the fluctuations became decoupled from a regular cycle but did not become less variable. Our results support the hypothesis that alternative prey decrease population cycle regularity but emphasize that such changes may be driven by dietary shifts among dominant specialist predators rather than exclusively through changes in the predator community