1,966 research outputs found

    Structural dynamic and aeroelastic considerations for hypersonic vehicles

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    The specific geometrical, structural, and operational environment characteristics of hypersonic vehicles are discussed with particular reference to aerospace plane type configurations. A discussion of the structural dynamic and aeroelastic phenomena that must be addressed for this class of vehicles is presented. These phenomena are in the aeroservothermoelasticity technical area. Some illustrative examples of recent experimental and analytical work are given. Some examples of current research are pointed out

    Pilot Open Case Series of Voice over Internet Protocol-Delivered Assessment and Behavior Therapy for Chronic Tic Disorders

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    Comprehensive Behavioral Intervention for Tics (CBIT) is an efficacious treatment for children with chronic tic disorders (CTDs). Nevertheless, many families of children with CTDs are unable to access CBIT due to a lack of adequately trained treatment providers, time commitment, and travel distance. This study established the interrater reliability between in-person and Voice over Internet Protocol (VoIP) administrations of the Yale Global Tic Severity Scale (YGTSS), and examined the preliminary efficacy, feasibility, and acceptability of VoIP-delivered CBIT for reducing tics in children with CTDs in an open case series. Across in-person and VoIP administrations of the YGTSS, results showed mean agreement of 91%, 96%, and 95% for motor, phonic, and total tic severity subscales. In the pilot feasibility study, 4 children received 8 weekly sessions of CBIT via VoIP and were assessed at pre- and posttreatment by an independent evaluator. Results showed a 29.44% decrease in clinician-rated tic severity from pre- to posttreatment on the YGTSS. Two of the 4 patients were considered treatment responders at posttreatment, using Clinical Global Impressions–Improvement ratings. Therapeutic alliance, parent and child treatment satisfaction, and videoconferencing satisfaction ratings were high. CBIT was considered feasible to implement via VoIP, although further testing is recommended

    Transonic unsteady airloads on an energy efficient transport wing with oscillating control surfaces

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    An aspect ratio 10.8 supercritical wing with oscillating control surfaces is described. The wing is instrumental with 252 static orifices and 164 in situ dynamic pressure transducers for studying the effects of control surface deflection on steady and unsteady pressures at transonic speeds. Results from initial wind tunnel tests conducted in the Langley Transonic Dynamics Tunnel are discussed. Unsteady pressure results are presented for two trailing edge control surfaces oscillating separately at the design Mach number of 0.78. Some experimental results are compared with analytical results obtained by using linear lifting surface theory

    Recent transonic unsteady pressure measurements at the NASA Langley Research Center

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    Four semispan wing model configurations were studied in the Transonic Dynamics Tunnel (TDT). The first model had a clipped delta planform with a circular arc airfoil, the second model had a high aspect ratio planform with a supercritical airfoil, the third model has a rectangular planform with a supercritical airfoil and the fourth model had a high aspect ratio planform with a supercritical airfoil. To generate unsteady flow, the first and third models were equipped with pitch oscillation mechanisms and the first, second and fourth models were equipped with control surface oscillation mechanisms. The fourth model was similar in planform and airfoil shape to the second model, but it is the only one of the four models that has an elastic wing structure. The unsteady pressure studies of the four models are described and some typical results for each model are presented. Comparison of selected experimental data with analytical results also are included

    Transonic steady- and unsteady-pressure measurements on a high-aspect-ratio supercritical-wing model with oscillating control surfaces

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    A supercritical wing with an aspect ratio of 10.76 and with two trailing-edge oscillating control surfaces is described. The semispan wing is instrumented with 252 static orifices and 164 in situ dynamic-pressure gages for studying the effects of control-surface position and motion on steady- and unsteady-pressures at transonic speeds. Results from initial tests conducted in the Langley Transonic Dynamics Tunnel at two Reynolds numbers are presented in tabular form

    Helios-2 Vela-Ariel-5 gamma-ray burst source position

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    The gamma-ray burst of 28 January 1976, one of 18 events thus far detected in interplanetary space with Helios-2, was also observed with the Vela-5A, -6A and the Ariel-5 satellites. A small source field is obtained from the intersection of the region derived from the observed time delays between Helios-2 and Vela-5A and -6A with the source region independently found with the Ariel-5 X-ray detector. This area contains neither any steady X-ray source as scanned by HEAO-A nor any previously catalogued X-ray, radio or infrared sources, X-ray transients, quasars, seyferts, globular clusters, flare stars, pulsars, white dwarfs or high energy gamma-ray sources. The region is however, within the source field of a gamma-ray transient observed in 1974, which exhibited nuclear gamma-ray line structure

    Outcomes in Trials for Management of Caries Lesions (OuTMaC):protocol

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    Background Clinical trials on caries lesion management use an abundance of outcomes, hampering comparison or combination of different study results and their efficient translation into clinical practice. Core outcome sets are an agreed standardized collection of outcomes which should be measured and reported in all trials for a specific clinical area. We aim to develop a core outcome set for trials investigating management of caries lesions in primary or permanent teeth conducted in primary or secondary care encompassing all stages of disease. Methods To identify existing outcomes, trials on prevention and trials on management of caries lesions will be screened systematically in four databases. Screening, extraction and deduplication will be performed by two researchers until consensus is reached. The definition of the core outcome set will by based on an e-Delhi consensus process involving key stakeholders namely patients, dentists, clinical researchers, health economists, statisticians, policy-makers and industry representatives. For the first stage of the Delphi process, a patient panel and a separate panel consisting of researchers, clinicians, teachers, industry affiliated researchers, policy-makers, and other interested parties will be held. An inclusive approach will be taken to involve panelists from a wide variety of socio-economic and geographic backgrounds. Results from the first round will be summarized and fed back to individuals for the second round, where panels will be combined and allowed to modify their scoring in light of the full panel’s opinion. Necessity for a third round will be dependent on the outcome of the first two. Agreement will be measured via defined consensus rules; up to a maximum of seven outcomes. If resources allow, we will investigate features that influence decision making for different groups. Discussion By using an explicit, transparent and inclusive multi-step consensus process, the planned core outcome set should be justifiable, relevant and comprehensive. The dissemination and application of this core outcome set should improve clinical trials on managing caries lesions and allow comparison, synthesis and implementation of scientific data. Trial registration Registered 12 April 2015 at COMET (http://www.comet-initiative.org

    Science, Math, Social Studies, and Language Arts Achievement of High School Students in Complete Programs of Agriscience Education

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    The purpose of this descriptive and comparative study was to describe the academic achievement of FFA (Future Farmers of America) members in a complete program of agriscience at Jackson County Comprehensive High School (JCCHS). A secondary purpose was to compare science, math, social studies, and language arts achievement of senior agriscience students/FFA members to the achievement of all seniors at JCCHS. The findings indicate that senior agriscience students/FFA members had a higher percentage of students achieving at the highest level (Pass Plus) of Language Arts on the GHSGT (Georgia High School Graduation Test) than the remaining student population at JCCHS. Senior agriscience students/FFA members also had a higher passing rate in comparison to all seniors at JCCHS on the social studies portion of the standardized test. The researchers postulate that further research needs to be conducted to identify the correlations between agriscience participation and performance on language arts and social studies standardized tests – areas where little or no research has been conducted. The researchers also recommend that other public school systems perform similar studies to determine the impact of secondary agriscience programs on student performance

    An Assessment of the Needs of Georgian Secondary Agricultural Educators

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    This purpose of this study was to determine the perception of secondary educators involved in Future Farmers of Georgia (FFG) schools throughout the country of Georgia concerning their needs for furthering the existing framework of agricultural education. The researchers used a modified focus group method to meet the aformentioned purpose of this study. The population for this study consisted of the high school agricultural education teachers and their administrators who were participating in the FFG Program (n=14). Qualitative data collected from the probe (first round) was used to generate a series of 46 statements. In the second round participants were asked to rank the 46 statements using a five point Likert-type scale. Due to events in the Former Republic of Georgia, the third round could not be conducted. Therefore, the researchers concluded that the round two data would be used to meet the purpose and objectives of this study. Participants strongly agreed that the FFG program strengthens leadership skills among their students and students have become more involved in practical/labor activities. They also agreed that gaining knowledge and skills from the FFG program will improve the future development of agricultural education in the country. Participants also strongly agreed that improvement of schools’ materials, technology, and development are necessary to improve the FFG program. Participants were either neutral or agreed with the following statements: due to the FFG program, academic performance has been increased among students; and students have greater academic success in history and geography
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