46,115 research outputs found
Orbit Transfer Vehicle (OTV) engine study, phase "A" extension 2
The operation of the Advanced Expander Cycle OTV engine was evaluated at high mixture ratios, and intermediate and low thrust levels to establish the impact upon the engine design and costs, and/or operating characteristics. The engine operation was analyzed at tank head and pumped idle conditions with the nozzle extension retracted. The engine performance, weight, and envelope parametrics data were expanded to include mixture ratios of 7.5 and 8.0
Commercial space services
An overview of space service opportunities as identified by a Wyle Laboratories' research team is given. Through the use of a baseline space scenario, a variety of space hardware, services, and commercial activities are identified and related on a time-phased basis. A model is presented to relate the potential functions of government and the private sector in a commercialized space environment during the period 1984 to 2004. Barriers, incentives and key issues are likewise identified and addressed to aid in the implementation of private sector activities for spacerelated programs. Broader awareness, legislative actions, incentive development and benefit analyses are considered in the presentation. The time-phased plan provides a useful planning and management tool, allows broader communication, and supports overall space commercialization program assessment
Solar heating and cooling technical data and systems analysis
The acquisition and processing of selected parametric data for inclusion in a computerized Data Base using the Marshall Information Retrieval and Data System (MIRADS) developed by NASA-MSFC is discussed. This data base provides extensive technical and socioeconomic information related to solar energy heating and cooling on a national scale. A broadly based research approach was used to assist in the support of program management and the application of a cost-effective program for solar energy development and demonstration
Fog dispersion
The concept of using the charged particle technique to disperse warm fog at airports is investigated and compared with other techniques. The charged particle technique shows potential for warm fog dispersal, but experimental verification of several significant parameters, such as particle mobility and charge density, is needed. Seeding and helicopter downwash techniques are also effective for warm fog disperals, but presently are not believed to be viable techniques for routine airport operations. Thermal systems are currently used at a few overseas airports; however, they are expensive and pose potential environmental problems
A review of the meteorological parameters which affect aerial application
The ambient wind field and temperature gradient were found to be the most important parameters. Investigation results indicated that the majority of meteorological parameters affecting dispersion were interdependent and the exact mechanism by which these factors influence the particle dispersion was largely unknown. The types and approximately ranges of instrumented capabilities for a systematic study of the significant meteorological parameters influencing aerial applications were defined. Current mathematical dispersion models were also briefly reviewed. Unfortunately, a rigorous dispersion model which could be applied to aerial application was not available
Silica heat shield sizing
The sensitivity of silica heat shield requirements to gap width, tile edge radius, and heat transfer distribution within tile gaps was investigated. A two-dimensional thermal model was modified and used to determine the effect of two dimensional heat transfer distributions at high temperature reusable surface insulation edges on shuttle thermal protection system (TPS) requirements. The sensitivity of TPS requirements to coating thickness, emissivity, substructure thickness, and changes in gap heating for several locations on shuttle was also studied. An inverse solution technique was applied to temperature data obtained in the Ames 20 MW turbulent duct in order to examine the effect of tile edge radius on TPS requirements. The derived heating values were then used to predict TPS requirements. Results show that increasing tile radius reduces TPS requirements
Identification and evaluation of educational uses and users for the STS. Educational planning for utilization of space shuttle ED-PLUSS
A planning and feasibility study to identify and document a methodology needed to incorporate educational programs into future missions and operations of the space transportation system was conducted. Six tasks were identified and accomplished during the study. The task statements are as follows: (1) potential user identification, (2) a review of space education programs, (3) development of methodology for user involvement, (4) methods to encourage user awareness, (5) compilation of follow-on ideas, and (6) response to NASA questions. Specific recommendations for improving the educational coverage of space activities are provided
En route position and time control of aircraft using Kalman filtering of radio aid data
Fixed-time-of-arrival (FTA) guidance and navigation is investigated as a possible technique capable of operation within much more stringent en route separation standards and offering significant advantages in safety, higher traffic densities, and improved scheduling reliability, both en route and in the terminal areas. This study investigated the application of FTA guidance previously used in spacecraft guidance. These FTA guidance techniques have been modified and are employed to compute the velocity corrections necessary to return an aircraft to a specified great-circle reference path in order to exercise en route time and position control throughout the entire flight. The necessary position and velocity estimates to accomplish this task are provided by Kalman filtering of data from Loran-C, VORTAC/TACAN, Doppler radar, radio or barometric altitude,and altitude rate. The guidance and navigation system was evaluated using a digital simulation of the cruise phase of supersonic and subsonic flights between San Francisco and New York City, and between New York City and London
Adherence to the MoodGYM program: Outcomes and predictors for an adolescent school-based population
Background
Program adherence has been associated with improved intervention outcomes for mental and physical conditions. The aim of the current study is to investigate adolescent adherence to an Internet-based depression prevention program in schools to identify the effect of adherence on outcomes and to ascertain the predictors of program adherence.
Methods
Data for the current study (N=1477) was drawn from the YouthMood Project, which was conducted to test the effectiveness of the MoodGYM program in reducing and preventing symptoms of anxiety and depression in an adolescent school-based population. The current study compares intervention effects across three sub-groups: high adherers, low adherers and the wait-list control condition.
Results
When compared to the control condition, participants in the high adherence intervention group reported stronger intervention effects at post-intervention and 6-month follow-up than participants in the low adherence group for anxiety (d=0.34–0.39 vs. 0.11–0.22), and male (d=0.43–0.59 vs. 0.26–0.35) and female depression (d=0.13–0.20 vs. 0.02–0.04). No significant intervention effects were identified between the high and low adherence groups. Being in Year 9, living in a rural location and having higher pre-intervention levels of depressive symptoms or self-esteem were predictive of greater adherence to the MoodGYM program.
Limitations
The program trialled is Internet-based and therefore the predictors of adherence identified may not generalise to face-to-face interventions.
Conclusions
The current study provides preliminary support for the positive relationship between program adherence and outcomes in a school environment. The identification of significant predictors of adherence will assist in identifying the type of user who will engage most with an online depression prevention program.ALC is supported by National Health and Medical Research Council (NHMRC)Fellowship 1013199, HC is supported by NHMRC Fellowship 525411, and KMG is supported by NHMRC Fellowship 42541
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