Advanced Supersonic Technology concept AST-100 characteristics developed in a baseline-update study

The advanced supersonic technology configuration, AST-100, is described. The combination of wing thickness reduction, nacelle recontouring for minimum drag at cruise, and the use of the horizontal tail to produce lift during climb and cruise resulted in an increase in maximum lift-to-drag ratio. Lighter engines and lower fuel weight associated with this resizing result in a six percent reduction in takeoff gross weight. The AST-100 takeoff maximum effective perceived noise at the runway centerline and sideline measurement stations was 114.4 decibels. Since 1.5-decibels tradeoff is available from the approach noise, the required engine noise supression is 4.9 decibels. The AST-100 largest maximum overpressure would occur during transonic climb acceleration when the aircraft was at relatively low altitude. Calculated standard +8 C day range of the AST-100, with a 292 passenger payload, is 7348 km (3968 n.mi). Fuel price is the largest contributor to direct operating cost. However, if the AST-100 were flown subsonically (M = 0.9), direct operating costs would increase approximately 50 percent because of time related costs

Unquenching the Quark Model and Screened Potentials

The low-lying spectrum of the quark model is shown to be robust under the effects of `unquenching'. In contrast, the use of screened potentials is shown to be of limited use in models of hadrons. Applications to unquenching the lattice Wilson loop potential and to glueball mixing in the adiabatic hybrid spectrum are also presented.Comment: 6 pages, 3 ps figures, revtex. Version to appear in J. Phys.

Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale

We conducted three torsion-balance experiments to test the gravitational inverse-square law at separations between 9.53 mm and 55 micrometers, probing distances less than the dark-energy length scale $\lambda_{\rm d}=\sqrt[4]{\hbar c/\rho_{\rm d}}\approx 85 \mu$m. We find with 95% confidence that the inverse-square law holds ($|\alpha| \leq 1$) down to a length scale $\lambda = 56 \mu$m and that an extra dimension must have a size $R \leq 44 \mu$m.Comment: 4 pages, 6 figure

Volume 2 - Literature review of adsorption on metal surfaces Final report, 1 May 1966 - 2 Jul. 1967

Atom and ion desorption energy, chemisorption theory and surface bonds, work functions and potential energy in literature review of adsorption on metal surface

Positron-neutrino correlations in 32Ar and 33Ar Decays: Probes of Scalar weak currents and nuclear isospin mixing

The positron-neutrino correlation in the 0^+ \to 0^+ \beta decay of ^{32}Ar was measured at ISOLDE by analyzing the effect of lepton recoil on the shape of the narrow proton group following the superallowed decay. Our result is consistent with the Standard Model prediction; for vanishing Fierz interference we find a=0.9989 \pm 0.0052 \pm 0.0036. Our result leads to improved constraints on scalar weak interactions. The positron-neutrino correlation in ^{33}Ar decay was measured in the same experiment; for vanishing Fierz interference we find a=0.944 \pm 0.002 \pm 0.003. The ^{32}Ar and ^{33}Ar correlations, in combination with precision measurements of the half-lives, superallowed branching ratios and beta endpoint energies, will determine the isospin impurities of the superallowed transitions. These will provide useful tests of isospin-violation corrections used in deducing |V_{\rm ud}| which currently indicates non-unitarity of the KM matrix.Comment: 15 pages, 6 figure

A search for 183-GHz emission from water in late-type stars

A search was made for 183 GHz line emission from water vapor in the direction of twelve Mira and two semiregular variables. Upper limits to the emission are in the range of 2000 to 5000 Jy. It is estimated that thermal emission from the inner regions of late type stellar envelopes will be on the order of ten Jy. Maser emission, according to one model, would be an order of magnitude stronger. From the limited set sampled, the possibility of very strong maser emission at 183 GHz cannot yet be ruled out

Stability of Learning Disabilities, Cognitive Growth, and L1 in English Learners: A Latent Class and Transition Analysis

This study investigated the stability of latent classes of students with learning disabilities among a heterogeneous sample of elementary-aged children whose first language is Spanish. To this end, children (N = 284) in Grades 1, 2, and 3 at Wave 1 (Year 1) were administered a battery of vocabulary, reading, math, and cognitive measures (short-term memory, working memory, rapid naming, inhibition) in both Spanish (L1) and English (L2). These same measures were administered 1 and 2 years later (Wave 2 and 3). Two stable latent classes of children at risk for learning disabilities (children with comorbid difficulties and children with high order difficulties) emerged that were distinct from two latent classes (balanced bilinguals, unbalanced bilinguals) of average achievers who varied in second language acquisition. Further, significant growth parameters that uniquely predicted the log-odds identifying latent classes across all status groups were measures of working memory. Finally, the significant contributions of L2 cognitive measures to latent class status were dependent on L1 cognitive performance. The results suggest that statistically distinct and stable latent classes of children with learning disabilities emerge under the umbrella of English language learners and that growth in the executive processes of working memory and first language cognitive performance play an important role in predictions of latent class status

Latent Class Analysis of Children with Math Difficulties and/or Math Learning Disabilities: Are There Cognitive Differences?

This study investigated whether a latent class of children with math difficulties (MD) or math learning disabilities (MLD) emerged within a heterogeneous sample of learners. A latent class analysis was computed on children (N = 447) in Grade 3 who were administered a battery of math, reading, and cognitive measures. The analysis yielded four important findings. First, a discrete latent class of children with MD (15% of the sample) or MLD (10% of the sample) emerged when setting cut-off scores at or below the 25th and 11th percentile, respectively. Second, model testing yielded a high probability of finding children with MD or MLD with reading problems as well as a latent class of low problem solvers with average reading and calculation scores. Third, knowledge of problem solving component processes, estimation and the executive component of WM were significant and unique correlates of latent classes at both cut-off points. Finally, children defined as MD at 25th percentile cut-off but not 11th percentile cut-off yielded high effect sizes on measures of reading, but not on cognitive measures, when compared with children identified at risk at both cut-off points. The results suggest that a statistically distinct latent class of children at risk for MD or MLD can be separated from a heterogeneous sample of children who vary in math, reading and fluid intelligence