1,260 research outputs found
Canister for Producing TMA Trails in the Upper Atmosphere
Payload canister for producing trimethyl aluminum trails in upper atmosphere using Nike-Cajun or Nike-Apache rocke
Optical properties of silicon carbide for astrophysical applications I. New laboratory infrared reflectance spectra and optical constants
Silicon Carbide (SiC) optical constants are fundamental inputs for radiative
transfer models of astrophysical dust environments. However, previously
published values contain errors and do not adequately represent the bulk
physical properties of the cubic (beta) SiC polytype usually found around
carbon stars. We provide new, uncompromised optical constants for beta- and
alpha-SiC derived from single-crystal reflectance spectra and investigate
quantitatively whether there is any difference between alpha- and beta-SiC that
can be seen in infrared spectra and optical functions.
Previous optical constants for SiC do not reflect the true bulk properties,
and they are only valid for a narrow grain size range. The new optical
constants presented here will allow narrow constraints to be placed on the
grain size and shape distribution that dominate in astrophysical environments.
In addition, our calculated absorption coefficients are much higher than
laboratory measurements, which has an impact on the use of previous data to
constrain abundances of these dust grains.Comment: 12 pages; 10 figures; laboratory optical constants available from
CDS. Accepted by Astronomy & Astrophysic
Factors that are Associated with Readiness to Transition from Pediatric to Adult Health Care in Cystic Fibrosis
Life expectancy of patients with Cystic Fibrosis (CF) has been increasing, with most children with CF expected to live at least into middle age adult years. Consequently, the majority of patients with CF will have to transition from a pediatric to an adult clinic. Unfortunately, few transition programs exist that attend to the physical, developmental, and psychological factors of adolescents with CF who need to transfer to adult clinics. Moreover, to date, there is a dearth of quantitative research that has been conducted to assess factors that may influence readiness to transition. The purpose of this study is to examine how specific psychosocial variables, such as locus of control, parental style, anxiety, and hope are associated with readiness to transition from pediatric to adult-centered health care for CF. A sample of 60 adolescents with CF (ages 14--20 years) and their caregivers were recruited from three pediatric clinics across the United States. Adolescents and caregivers each were required to complete a packet of questionnaires. Results revealed that age is positively correlated with youth and parents` ratings of transition readiness. Additionally, as hypothesized, youth reported higher readiness scores than their parents\u27 ratings of the youth\u27s readiness to transition. Further, the current study found that parental vicarious hope was significantly associated with increased youth-and parent-rated readiness to transition. Consequently, when developing transition programs, it may be beneficial to include methods to increase parents` level of hope for their child. Ultimately, future research is still needed to understand the potential role that a variety of psychosocial factors may play in adolescents` readiness to move from a pediatric to adult clinic, and will be essential in the continued development of CF transition programs across the country
Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 3: Gasification, process fuels, and balance of plant
Results are presented of an investigation of gasification and clean fuels from coal. Factors discussed include: coal and coal transportation costs; clean liquid and gas fuel process efficiencies and costs; and cost, performance, and environmental intrusion elements of the integrated low-Btu coal gasification system. Cost estimates for the balance-of-plant requirements associated with advanced energy conversion systems utilizing coal or coal-derived fuels are included
Synthesis of bulk, dense, nanocrystalline yttrium aluminum garnet from amorphous powders
Amorphous powders of Al2O3x2014;37.5 mol% Y2O3 (yttrium aluminum garnet (YAG)) were prepared by coprecipitation, decomposed at 800xB0;C, and hot-pressed uniaxally at low temperature (600xB0;C) and a moderate pressure (750 MPa). Optimum conditions yielded microstructures with only 2% porosity and partial crystallization of YAG. Further processing using high quasi-hydrostatic pressure (1 GPa) at 1000xB0;C enabled the production of fully crystallized YAG with gt;96% relative density and a nanocrystalline grain size of x223C;70 nm. 13
Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy Conversion subsystems and components. Part 2: Primary heat input systems and heat exchangers
Primary heat input systems and heat exchangers were evaluated for advanced energy conversion systems. Results are presented and discussed
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