Design Optimization of Gas Generator Hybrid Propulsion Boosters

A methodology used in support of a study for NASA/MSFC to optimize the design of gas generator hybrid propulsion booster for uprating the National Space Transportation System (NSTS) is presented. The objective was to compare alternative configurations for this booster approach, optimizing each candidate concept on different bases, in order to develop data for a trade table on which a final decision was based. The methodology is capable of processing a large number of independent and dependent variables, adjusting the overall subsystems characteristics to arrive at a best compromise integrated design to meet various specific optimization criteria subject to selected constraints. For each system considered, a detailed weight statement was generated along with preliminary cost and reliability estimates

DEPREDATION CLAIM BEHAVIOR AND TOLERANCE OF WILDLIFE IN WYOMING

Wyoming Game and Fish Department depredation payments were established to increase landowner tolerance toward, and this the supply of, certain types of wildlife. This study examined how socio-economic and demographic characteristics of farmers and ranchers in Wyoming relate to tolerance toward wildlife and depredation claim submission. The severity of depredation and landowner satisfaction with the depredation policy were evaluated. The financial stability and economic intent of farmers and ranchers significantly influenced tolerance toward wildlife. Landowners tended to be less tolerant of depredation ensuing from elk. The complexity of the submission process was a deterrent to damage claim submissions.depredation, probit model, wildlife, Resource /Energy Economics and Policy,

Distribution and Ecology of Orconectes iowaensis Fitzpatrick and Orconectes rusticus (Girard) in Minnesota

During 1979, a field study was conducted to determine the species of crayfish present in southern Minnesota. Specimens of Orconectes iowaensis Fitzpatrick, Orconectes rusticus (Girard), and Orconectes virilis (Hagen) were collected. These represent new state records for O. iowaensis and O. rusticus. O. iowaensis appears restricted to the Root River drainage system in extreme southeastern Minnesota. O. rusticus was found in the West Fork of the Des Moines River in southwestern Minnesota and the Cedar River drainage system in south central Minnesota. Notes on the ecology of these species are included

Prevention for a Healthier California: Investments in Disease Prevention Yield Significant Savings, Stronger Communities

Estimates how much the state and the nation could save in healthcare costs by investing in disease prevention through community programs that increase physical activity, improve nutrition, and reduce tobacco use. Provides examples of prevention efforts

A Covariate-Adjusted Homogeneity Test with Application to Facial Recognition Accuracy Assessment

Ordinal scores occur commonly in medical imaging studies and in black-box forensic studies \citep{Phillips:2018}. To assess the accuracy of raters in the studies, one needs to estimate the receiver operating characteristic (ROC) curve while accounting for covariates of raters. In this paper, we propose a covariate-adjusted homogeneity test to determine differences in accuracy among multiple rater groups. We derived the theoretical results of the proposed test and conducted extensive simulation studies to evaluate the finite sample performance of the proposed test. Our proposed test is applied to a face recognition study to identify statistically significant differences among five participant groups

Model for a partially coherent Gaussian beam in atmospheric turbulence with application in Lasercom

Analytic expressions for the mutual coherence function (MCF) and the scintillation index of a partially coherent lowest order Gaussian beam wave propagating through the atmosphere (based on Kolmogorov spectrum model) are developed for the pupil plane of a receiving system. Partial coherence of the beam is modeled as a thin (complex) phase screen with Gaussian spectrum (Rytov theory and ABCD ray matrices are applied). The relation between the second- and fourth-order statistics for a beam with any degree of coherence in the atmosphere is introduced with the help of effective beam parameters, deduced from the free-space MCF. In particular, the scintillation (in weak and strong atmospheric conditions), based on these parameters, is studied as a function of the diffuser\u27s strength and that of the atmosphere. The model is applied for the calculation of the SNR and bit error rates (OOK modulation) of the communication link with diffuser at the transmitter and slow detection system. The improvement of bit error rates is observed in weak and strong atmospheric turbulence. In the weak regime, the optimal diffuser can be found

Small Grain Production: Seeding Dates and Clipping Frequency

Agronom

Infiltration Through Reconstructed Surface Mined Spoils and Soils

An extensive series of tests involving reconstructed profiles of spoil and topsoil material from a Western Kentucky surface mine site was conducted with a laboratory infiltrometer system. Infiltration through the reconstructed spoil profiles was very slow despite the coarse nature of the material. Low infiltration rates could be attributed to the material having a well-graded texture and to the high densities of the profiles. Infiltration through topsoil horizons was controlled, for the most part, by conditions at the surface. Following wetting, infiltration rates were primarily controlled by the hydraulic characteristics of the less permeable sub horizon of the spoil material. Except in very early stages, rainfall rate had little effect upon infiltration rate (or volume) through the spoil and topsoil profiles. Infiltration was, however, significantly influenced by initial moisture content and density