Loading and heating of a large flat plate at Mach 7 in the Langley 8-foot high-temperature structures tunnel

Surface pressure and cold-wall heating rate distributions (wall-temperature to total-temperature ratio approximately 0.2) were obtained on a large, flat calibration panel at a nominal Mach number of 7 in an 8-foot high-temperature structures tunnel. Panel dimensions were 42.5 by 60.0 in. Test objectives were: (1) to map available flat-plate loading and heating provided by the facility and (2) to determine effectiveness of leading-edge bluntness, boundary-layer trips, and aerodynamic fences in generating a uniform, streamwise turbulent flow field over the test surface of a flat-sided panel holder

Aerothermal performance and structural integrity of a Rene 41 thermal protection system at Mach 6.6

A flightweight panel based on a metallic thermal-protection-system concept for hypersonic and reentry vehicles was subjected repeatedly to thermal cycling by quartz-lamp radiant heating using a thermal history representative of a reentry heat pulse and to aerodynamic heating at heating rates required to sustain a surface temperature of 1089 K (1960 R). The panel consisted of a corrugated heat shield and support members of 0.05-cm (0.02-in.) thick Rene 41 of riveted construction and 5.08-cm (2-in.) thick silica fibrous insulation packages covered by Rene 41 foil and inconel screening. All tests were conducted in the Langley 8-foot high-temperature structures tunnel with the heat shield corrugations alined in the stream direction. The panel sustained 5.33 hr of intermittent radiant heating and 6.5 min of intermittent aerodynamic heating of up to 1-min duration for differential pressures up to 6.2 kPa (0.9 psi) with no apparent degradation of thermal or structural integrity, as indicated by temperature distributions and results from load deflection tests and vibration surveys of natural frequencies

SPECTROSCOPY OF DEFECTS IN NEUTRON IRRADIATED AMMONO-THERMAL GaN BY COMBINING PHOTOIONIZATION, PHOTOLUMINESCENCE AND POSITRON ANNIHILATION TECHNIQUES

In this work, pulsed photoionization as well as photoluminescence and positron annihilation spectroscopy were combined to detect different species of defects. The GaN crystals, grown by the ammono-thermal method, doped with Mn as well as Mg impurities and irradiated with different fluences of reactor neutrons, were examined to clarify the role of the technological and radiation defects. The evolution of the prevailing photoactive centres was examined by pulsed photoionization spectroscopy. Positron annihilation spectroscopy was applied to reveal vacancy-type defects.Peer reviewe

Few-nucleon systems in translationally invariant harmonic oscillator basis

We present a translationally invariant formulation of the no-core shell model approach for few-nucleon systems. We discuss a general method of antisymmetrization of the harmonic-oscillator basis depending on Jacobi coordinates. The use of a translationally invariant basis allows us to employ larger model spaces than in traditional shell-model calculations. Moreover, in addition to two-body effective interactions, three- or higher-body effective interactions as well as real three-body interactions can be utilized. In the present study we apply the formalism to solve three and four nucleon systems interacting by the CD-Bonn nucleon-nucleon potential. Results of ground-state as well as excited-state energies, rms radii and magnetic moments are discussed. In addition, we compare charge form factor results obtained using the CD-Bonn and Argonne V8' NN potentials.Comment: 25 pages. RevTex. 13 Postscript figure

Processamento auditivo: marcadores de tempo por habilidade auditiva

Model of study: descriptive study and cross. Purpose: to characterize the acquisition time of each hearing ability worked with children diagnosed with Disturbance of Central Auditory Processing, school age, from a speech therapy program pre-established, which lasted 20 sessions. Methods: participated in speech therapy 8 patients aged seven to nine years, school age, in a public school. For the analysis of the data set as a criterion for participation, the individual who completed at least 16 sessions of therapy, or one that reached the proposed objectives (adequacy of skills) in fewer sessions. For each session, which occurred weekly, lasting 40 minutes each, was conducted cursive record the child’s performance for each of the skills worked (location, discrimination, recognition, figure-ground/closing, comprehension e memory). Subsequently, we performed a descriptive content analysis of similarity between the skills. In the record was marked session considered the end of the activity, that is, the acquisition of skill. Results: the number of sessions held by the study subjects ranged from 10 to 20 sessions and the average length of sessions for each skill acquisition of auditory worked varied from three to 16 sessions. Conclusion: it was possible to observe adequacy in auditory skills in all subjects of the group, with a range of time worked for each skill. Studies with larger samples are essential to achieve time markers for the acquisition of auditory skills in this population segment.Modelo de estudo: estudo descritivo e transversal. Objetivo do estudo: caracterizar o tempo de aquisi- ção de cada habilidade auditiva trabalhada em crianças diagnosticadas com Distúrbio do Processamento Auditivo Central, em idade escolar, a partir de um programa de intervenção fonoaudiológica pré-estabelecido, com duração máxima de 20 sessões. Metodologia: foram selecionados, para a intervenção fonoaudiológica, 8 indivíduos na faixa etária de sete a nove anos, em idade escolar, de uma escola pública e que completasse, no mínimo, 16 sessões de terapia, ou, ainda, aquele que atingisse os objetivos propostos (adequação das habilidades) em menor número de sessões. Para cada sessão, que ocorreu semanalmente, com duração de 40 minutos, foi realizado registro cursivo do desempenho da crian- ça, para cada uma das habilidades trabalhadas (localização, discriminação, reconhecimento, figura-fundo/ fechamento, compreensão e memória). Posteriormente, foi realizada análise do conteúdo descritivo por semelhança entre as habilidades. No registro, foi assinalada a sessão considerada como término da atividade, isto é, a aquisição da habilidade. Resultados: o número de sessões realizadas pelos indivíduos do estudo variou de 10 a 20 sessões, sendo que o tempo médio de sessões para a aquisição de cada habilidade auditiva trabalhada oscilou entre três e 16 sessões. Conclusões: foi possível observar adequação das habilidades auditivas em todos os indivíduos do estudo, com variação de tempo para cada habilidade trabalhada. Estudos com maior casuística são fundamentais para que se alcancem marcadores de tempo para aquisição de habilidades auditivas, nesse segmento populacional