16,416 research outputs found
NSF presentation
Wind energy conversion research is considered in the framework of the national energy problem. Research and development efforts for the practical application of solar energy -- including wind energy -- as alternative energy supplies are assessed in: (1) Heating and cooling of buildings; (2) photovoltaic energy conversion; (3) solar thermal energy conversion; (4) wind energy conversion; (5) ocean thermal energy conversion; (6) photosynthetic production of organic matter; and (7) conversion of organic matter into fuels
Effect of White Spruce Release on Subsequent Defoliation by the Yellowheaded Spruce Sawfly, Pikonema Alaskensis (Hymenoptera: Tenthredinidae)
Hand release of 22 5-year-old white spruce, Picea glauca (Moench) Voss, dramatically increased the amount of defoliation by the yellowheaded spruce sawfly, Pikonema alaskens is . The percent defoliation of the released trees was six times the defoliation in the control trees. A light overstory for young white spruce is suggested as a silvicultural method of reducing defoliation by this sawfly
Aeroacoustic research: An Army perspective
A short perspective of the Army aeroacoustic research program is presented that emphasizes rotary wing, aerodynamically generated noise. Exciting breakthroughs in experimental techniques and facilities are reviewed which are helping build a detailed understanding of helicopter external noise. Army and joint Army/NASA supported research programs in acoustics which promise to reduce the noise of future helicopters without severe performance penalties are included
Swashplate control system
A mechanical system to control the position of a rotating swashplate is developed. This system provides independent lateral cyclic, longitudinal cyclic and collective pitch control of a helicopter rotor attached to the swashplate, without use of a mixer box. The system also provide direct, linear readout of cyclic and collective swashplate positions
Aeroacoustic research programs at the Army Aviation Research and Technology Activity
The Army rotorcraft aeroacoustic programs are reviewed, highlighting the theoretical and experimental progress made by Army researchers in the physical understanding of helicopter impulsive noise. The two impulsive noise sources addressed over this past decade are high-speed impulsive noise and blade-vortex interaction noise, both of which have had and will continue to have an increasing influence on Army rotorcraft design and operations. The advancements discussed are in the areas of in-flight data acquisition techniques, small-scale-model tests in wind tunnels, holographic interferometry/tomographic techniques, and the expanding capabilities of computational fluid dynamics in rotorcraft acoustic problems. Current theoretical prediction methods are compared with experimental data, and parameters that govern model scaling are established. The very successful cooperative efforts between the Army, NASA, and industry are also addresse
Interim user's manual for boundary layer integral matrix procedure, version J
A computer program for analyzing two dimensional and axisymmetric nozzle performance with a variety of wall boundary conditions is described. The program has been developed for application to rocket nozzle problems. Several aids to usage of the program and two auxiliary subroutines are provided. Some features of the output are described and three sample cases are included
Boundary layer integral matrix procedure code modifications and verifications
A summary of modifications to Aerotherm's Boundary Layer Integral Matrix Procedure (BLIMP) code is presented. These modifications represent a preliminary effort to make BLIMP compatible with other JANNAF codes and to adjust the code for specific application to rocket nozzle flows. Results of the initial verification of the code for prediction of rocket nozzle type flows are discussed. For those cases in which measured free stream flow conditions were used as input to the code, the boundary layer predictions and measurements are in excellent agreement. In two cases, with free stream flow conditions calculated by another JANNAF code (TDK) for use as input to BLIMP, the predictions and the data were in fair agreement for one case and in poor agreement for the other case. The poor agreement is believed to result from failure of the turbulent model in BLIMP to account for laminarization of a turbulent flow. Recommendations for further code modifications and improvements are also presented
Young people’s use of video games as entertainment: Motivations and perceived implications, with a focus on the social aspects of video gaming.
Children’s motivation for video gaming (the activity of playing video games), and specifically their social motivation for playing, is a relatively new field of academic academic enquiry. Growing concern over adolescents’ and children’s use of video games, and the time they spend playing, has spawned research on the possibility of video ‘gaming disorder’ (Faust & Prochaska, 2018). ‘Gaming disorder’, which is included with the 11th revision of the ICD (International classification of diseases), is described as impaired control over (video) gaming, increasing priority given to gaming over other activities and continued video gaming despite the occurrence of negative consequences (World Health Organisation, 2018). Consequently, video gaming is an activity of recent interest and through this project I will aim to explore children and young people’s motivations for video gaming, how they are accessing/using video games, along with potential problematic use of video games within a population of young people in the South West of England. In order to understand young people’s experience of playing video games a mixed methods, two phase, research design was used. The first phase of this study employed the use of questionnaires incorporating an adapted version of the Internet Addiction Test (Young, 1998). The participants in Phase 1 were from a mixture of primary and secondary UK schools. These children were in school years 4/5 (8-10 years old) and years 8/9 (12-14 years old). Results from the adapted version of the questionnaire demonstrated that 16.8% of the 214 participants experienced a high level of video game preoccupation, and that male participants and primary school aged participants were more vulnerable to video game preoccupation. The data also revealed that just over a quarter of the participants typically played video games for at least three hours in one sitting, while just under half of the participants played video games at least once a day. Phase 2 of this research involved 27 participants who were involved in Phase 1. These participants took part in semi-structured interviews which were analysed using Braun and Clarke’s model of thematic analysis (2006). The participants’ responses revealed their perceptions on a range of, both positive and negative, impacts video gaming has upon their social interactions, their social opportunities, their learning, their mood and their overall wellbeing. This project adds to the growing body of research regarding young people’s uses and experiences of video gaming, and the social implications for young people who participate in the activity. This thesis concludes with an exploration of the limitations of this research, future directions for study and the implications for educational psychology practice
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