Generalized Newton-Raphson trajectory optimization-generator 1

Computer program constructs a sequence of optimal solutions to dynamically-approximate linear equations. Specification of the number and type of subarcs in the optimal solution allows simultaneous satisfaction of all switching criteria

High temperature measurement of water vapor absorption

An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction

Examining the Reliability, Validity and Factor Structure of the DRS-15 with College Athletes

Hardiness, comprising feelings of commitment, control and challenge, is most frequently measured with the Dispositional Resiliency Scale (DRS), but little work has been done with the brief 15-item version. To examine the factor structure, reliability, validity, and item functioning for gender invariance of the 15-item DRS with 525 collegiate athletes from a wide range of sports. Convergent and divergent validity were examined through relationships with mental toughness, grit and competitive anxiety. Participants completed measures of mental toughness, optimism, grit, competitive anxiety, and the DRS-15. Confirmatory Factor Analysis revealed a poor fit for the three-factor hardiness model, and subsequent exploratory factor analysis yielded a four-factor model with better fit than the three-factor structure. Additionally, several items appear to be biased towards males or females. The fourth factor may be unique to the collegiate athlete population, and related to perceived lack of control in future life directions. Convergent and divergent validity were supported through correlations of DRS scores with related measures. The four-factor model should be tested with different samples to determine if these changes should be adapted when using the DRS-15 in collegiate athletics or other settings

Energy efficient engine ICLS Nacelle detail design report

The results of the detail design of the Nacelle for the General Electric Energy Efficient Engine (E3) Integrated Core Low Spool (ICLS) test vehicles are presented. A slave nacelle is designed for the ICLS test. Cost and reliability are the important factors considered. The slave nacelle simulates the internal flow lines of the actual Flight Propulsion System (FPS) but has no external fairing. The aerodynamic differences between the ICLS and FPS nacelles are presented, followed by the structural description and analysis of the various nacelle components

USING NONLINEAR FIXED AND MIXED MODELS TO STUDY ACCLIMATION TO HEAT STRESS IN CATTLE

Researchers studying acclimation of cattle to heat stress want to know if exposure to heat stress in controlled chambers will help cattle adjust to climatic conditions in the field. The four parameter nonlinear PET model is used to study the relationship between core body temperature and ambient temperature. This model works well when cattle are challenged by heat stress but the model is less useful for thermoneutral conditions. Both proc Nlin and Nlmixed are used to compare and contrast the field parameters between the controlled and the potentially acclimated group. Simulation studies were used to compare the effectiveness of proc Nlin versus proc Nlmixed. The results are helpful, not only for researchers who study acclimation, but also for those who study sensitivity, tolerance and robustness of cattle during heat stress

Provjera pouzdanosti, valjanosti i faktorske strukture skale DRS-15 na uzorku studenata sportaša

Hardiness, comprising feelings of commitment, control and challenge, is most frequently measured with the Dispositional Resiliency Scale (DRS), but little work has been done with the brief 15-item version.To examine the factor structure, reliability, validity, and item functioning for gender invariance of the 15-item DRS with 525 collegiate athletes from a wide range of sports. Convergent and divergent validity were examined through relationships with mental toughness, grit and competitive anxiety. Participants completed measures of mental toughness, optimism, grit, competitive anxiety, and the DRS-15.Confirmatory Factor Analysis revealed a poor fit for the three-factor hardiness model, and subsequent exploratory factor analysis yielded a four-factor model with better fit than the three-factor structure. Additionally, several items appear to be biased towards males or females. The fourth factor may be unique to the collegiate athlete population, and related to perceived lack of control in future life directions. Convergent and divergent validity were supported through correlations of DRS scores with related measures.The four-factor model should be tested with different samples to determine if these changes should be adapted when using the DRS-15 in collegiate athletics or other settings.Aunque la resistencia es un constructo que consta de sentimientos de compromiso, control y desafío, y normalmente se mide por la Escala de resistencia disposicional (DRS), no hay muchas investigaciones que verifican características de versiones abreviadas de esta escala.El objetivo de esta investigación es examinar la estructura factorial, fiabilidad, validez e invariancia de género en el funcionamiento de las partículas de la escala DRS-15 abreviada en la muestra de 525 estudiantes deportistas de deportes diferentes. La validez convergente y divergente de la escala se comprobó en relación con la resistencia mental, perseverancia y ansiedad en situaciones competitivas. Los encuestados rellenaron encuestas que medían la resistencia mental, optimismo, perseverancia, ansiedad en situaciones competitivas y escala DRS-15.Con el análisis factorial confirmatorio de la estructura trifactorial no se han conseguido índices satisfactorios de concordancia. Gracias al análisis factorial exploratorio posterior se han obtenido cuatro factores que en el análisis confirmatorio tienen mejores índices de concordancia en comparación con la estructura trifactorial. Además, algunas partículas no muestran invariancia de género. La estructura de cuatro factores podría ser específica para la populación de estudiantes deportistas y relacionada con la percepción de la falta del control de la futura dirección de la vida. Validez convergente y divergente de la escala se ha confirmado por las correlaciones de la escala DRS-15 y otros instrumentos de medida relevantes.Es necesario averiguar la estructura de cuatro factores de la escala en otras muestras de deportistas y no deportistas para confirmar la conveniencia de utilizar estos cuatro factores en las muestras específicas.Iako je čvrstoća konstrukt koji objedinjuje osjećaje predanosti, kontrole i izazova, i najčešće je mjerena Upitnikom dispozicijske otpornosti (DRS), ne postoji puno istraživanja koja provjeravaju karakteristike skraćene verzije ove skale.Cilj je ovoga istraživanja ispitati faktorsku strukturu, pouzdanost, valjanost i spolnu invarijantnost u funkcioniranju čestica skraćene skale DRS-15 na uzorku 525 studenata sportaša iz različitih sportova. Konvergentna i divergentna valjanost skale provjerena je u odnosu na mentalnu izdržljivost, ustrajnost i anksioznost u kompetitivnim situacijama. Ispitanici su ispunili upitnike koji mjere mentalnu izdržljivost, optimizam, ustrajnost, anksioznost u kompetitivnim situacijama i skalu DRS-15.Konfirmatornom faktorskom analizom trofaktorske strukture nisu dobiveni zadovoljavajući indeksi slaganja. Naknadnom su eksploratornom faktorskom analizom dobivena četiri faktora, koja u konfirmatornoj analizi imaju bolje indekse slaganja u odnosu na trofaktorsku strukturu. Također, nekoliko čestica ne pokazuje invarijantnost s obzirom na spol. Četverofaktorska bi struktura mogla biti specifična za populaciju studenata sportaša i povezana s percepcijom nedostatka kontrole budućeg smjera života. Konvergentna i divergentna valjanost skale potvrđena je korelacijama skale DRS-15 i ostalih relevantnih mjernih instrumenata.Potrebno je provjeriti četverofaktorsku strukturu skale na drugim uzorcima sportaša i nesportaša kako bi se utvrdila primjerenost korištenja ovih četiriju faktora na specifičnim uzorcima

Near-Term Effects of Perennial Grasses on Soil Carbon and Nitrogen in Eastern Nebraska

Incorporating native perennial grasses adjacent to annual row crop systems managed on marginal lands can increase system resiliency by diversifying food and energy production. This study evaluated (1) soil organic C (SOC) and total N stocks (TN) under warm-season grass (WSG) monocultures and a low diversity mixture compared to an adjacent no-till continuous-corn system, and (2) WSG total above-ground biomass (AGB) in response to two levels of N fertilization from 2012 to 2017 in eastern Nebraska, USA. The WSG treatments consisted of (1) switchgrass (SWG), (2) big bluestem (BGB), and (3) low-diversity grass mixture (LDM; big bluestem, Indiangrass, and sideoat grama). Soils were sampled at fixed depth increments (0–120 cm) in the WSG plots and in the adjacent corn experiment in 2012 and 2017. Soil stocks (Mg ha-1) of SOC and TN were calculated on an equivalent soil mass (ESM) basis and compared within the three WSG treatments as well as between experiments (corn compared to the mean of all WSGs). Soil organic C and TN stocks within soil layers and cumulative stocks responded to the main effect of WSG (PWSG \u3c 0.05) but were no different when comparing the WSGs to corn (Pexpt = NS). Both SOC/TN stocks and cumulative stocks were generally greater in the LDM compared to the BGB. Neither SOC nor TN changed over time under either the WSGs or corn. Warm-season grass AGB responded to a three-way interaction of year, N rate, and WSG (p = 0.0007). Decreases in AGB over time were significant across WSGs and N levels except for SWG at 56 kg N ha-1 and LDM at 112 kg N ha-1. Above-ground biomass was generally greater in the LDM after the first harvest year (2013). Results suggest that incorporating WSGs into marginal cropland can maintain SOC and TN stocks while providing a significant source of biomass to be used in energy production or in integrated livestock systems

ASSESSING REFINEMENTS IN MODELING SINUSOIDAL CONDITIONS USED TO DRIVE CATTLE BODY TEMPERATURES

A model, termed the PET model, is used to estimate body temperature in cattle challenged by hot cyclic chamber temperatures. The model is based on Newton\u27s law of cooling, driven by an estimated sinusoidal function. In practice, it is often difficult to maintain hot sinusoidal fluctuations in chamber temperatures. However, it is possible to model cyclic chamber temperatures using a discrete Fourier series. By increasing the precision in estimating the cyclic temperature driving function, we can more precisely estimate the parameters in the PET model. Simulation studies were performed to investigate the effect of under- and over-parameterization on accuracy of estimates, performance of a number of model selection criteria, and on nonlinear behavior such as intrinsic and parameter-effects curvature, bias, excess variance, and skewness. Our results will help researchers decide how to model ambient temperatures producing heat stress in cattle and improve estimates for evaluating management strategies