Analysis of electric propulsion electrical power conditioning component technology. Volume 1 - Data bank Final report

Analysis of electric propulsion electric power conditioning component technology - data revie

Analysis of electric propulsion electrical power conditioning component technology, volume 2 Final report

Large solar arrays to provide power for electric propulsion engine for Mars mapper spacecraf

Universal velocity distributions in an experimental granular fluid

We present experimental results on the velocity statistics of a uniformly heated granular fluid, in a quasi-2D configuration. We find the base state, as measured by the single particle velocity distribution $f(c)$, to be universal over a wide range of filling fractions and only weakly dependent on all other system parameters. There is a consistent overpopulation in the distribution's tails, which scale as $f\propto\exp(\mathrm{const.}\times c^{-3/2})$. More importantly, the high probability central region of $f(c)$, at low velocities, deviates from a Maxwell-Boltzmann by a second order Sonine polynomial with a single adjustable parameter, in agreement with recent theoretical analysis of inelastic hard spheres driven by a stochastic thermostat. To our knowledge, this is the first time that Sonine deviations have been measured in an experimental system.Comment: 13 pages, 15 figures, with minor corrections, submitted to Phys. Rev.

Caging dynamics in a granular fluid

We report an experimental investigation of the caging motion in a uniformly heated granular fluid, for a wide range of filling fractions, $\phi$. At low $\phi$ the classic diffusive behavior of a fluid is observed. However, as $\phi$ is increased, temporary cages develop and particles become increasingly trapped by their neighbors. We statistically analyze particle trajectories and observe a number of robust features typically associated with dense molecular liquids and colloids. Even though our monodisperse and quasi-2D system is known to not exhibit a glass transition, we still observe many of the precursors usually associated with glassy dynamics. We speculate that this is due to a process of structural arrest provided, in our case, by the presence of crystallization.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

Participation in Social Activities among Adolescents with an Autism Spectrum Disorder

Background: Little is known about patterns of participation in social activities among adolescents with an autism spectrum disorder (ASD). The objectives were to report nationally representative (U.S.) estimates of participation in social activities among adolescents with an ASD, to compare these estimates to other groups of adolescents with disabilities, and examine correlates of limited social participation. Methods and Findings: We analyzed data from wave 1 of the National Longitudinal Transition Study 2, a large cohort study of adolescents enrolled in special education. Three comparison groups included adolescents with learning disabilities, mental retardation, and speech/language impairments. Adolescents with an ASD were significantly more likely never to see friends out of school (43.3%), never to get called by friends (54.4%), and never to be invited to social activities (50.4%) when compared with adolescents from all the other groups. Correlates of limited social participation included low family income and having impairments in conversational ability, social communication, and functional cognitive skills. Conclusions: Compared with prior research, our study significantly expands inquiry in this area by broadening the range of social participation indicators examined, increasing the external validity of findings, focusing on the under-studied developmental stage of adolescence, and taking an ecological approach that included many potential correlates of social participation. There were notable differences in social participation by income, a dimension of social context seldo

Minutes 1875

https://place.asburyseminary.edu/freemethodistminutesyearbooks/1013/thumbnail.jp

Postsecondary Employment Experiences among Young Adults with an Autism Spectrum Disorder

Objective: We examined postsecondary employment experiences of young adults with an autism spectrum disorder (ASD) and compared these outcomes with those of young adults with different disabilities. Method: Data were from Wave 5 of the National Longitudinal Transition Study 2 (NLTS2), a nationally representative survey of young adults who had received special education services during high school. We examined the prevalence of ever having had—and currently having—a paid job at 21–25 years of age. We analyzed rates of full employment, wages earned, number of jobs held since high school, and job types. Results: About half (53.4%) of young adults with an ASD had ever worked for pay outside the home since leaving high school, the lowest rate among disability groups. Young adults with an ASD earned an average of $8.10 per hour, significantly lower than average wages for young adults in the comparison groups, and held jobs that clustered within fewer occupational types. Odds of ever having had a paid job were higher for those who were older, from higher-income households, and with better conversational abilities or functional skills. Conclusions: Findings of worse employment outcomes for young adults with an ASD suggest this population is experiencing particular difficulty in successfully transitioning into employment. Research is needed to determine strategies for improving outcomes as these young adults transition into adulthood