26,262 research outputs found
A Documentation and Analysis of Surdna Arts Teachers Fellowship Program (SATF): The First Decade 2000-2010
Based on documents, interviews, and site visits, reviews the design and impact of a program to boost teaching and learning quality at public arts high schools by supporting teachers' artistic and professional development. Lists issues for consideration
The scatter of obliquely incident plane waves from a corrugated conducting surface
A physical optics solution is presented for the scattering of plane waves from a perfectly conducting corrugated surface in the case of waves incident from an arbitrary direction and for an observer far from the surface. This solution was used to compute the radar cross section of the surface in the case of backscatter from irregular (i.e., stochastic) corrugations and to point out a correction to the literature on this problem. A feature of the solution is the occurrence of singularities in the scattered fields which appear to be a manifestation of focussing by the surface at its stationary points. Whether or not the singularities occur in the solution depends on the manner in which one restricts the analysis to the far field
Comparison of approximate and numerical analyses of nonlinear combustion instability
At the present time, there are three general analytical techniques available to study problems of unsteady motions in rocket motors: linear stability analysis; approximate nonlinear analysis, founded on examining the behavior of coupled normal modes; and numerical calculations based on
the conservation equations for one-dimensional flows. The last two yield the linear results as a limit. It is the main purpose of this paper to check the accuracy of the approximate analysis against the numerical analysis for some special cases. The results provide some justification for using the approximate analysis to study three dimensional problems
A survey of manufacturers of solar thermal energy systems
Sixty-seven firms that had received funding for development of solar thermal energy systems (STES) were surveyed. The effect of the solar thermal technology systems program in accelerating (STES) were assessed. The 54 firms still developing STES were grouped into a production typology comparing the three major technologies with three basic functions. It was discovered that large and small firms were developing primarily central receiver systems, but also typically worked on more than one technology. Most medium-sized firms worked only on distributed systems. Federal support of STES was perceived as necessary to allow producers to take otherwise unacceptable risks. Approximately half of the respondents would drop out of STES if support were terminated, including a disproportionate number of medium-sized firms. A differentiated view of the technology, taking into account differing firm sizes and the various stages of technology development, was suggested for policy and planning purposes
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Scenarios of energy efficiency and CO2 emissions reduction potential in the buildings sector in China to year 2050
As China’s rapid urbanization continues and urban dwellers become more affluent, energy use in buildings is expected to grow. To understand how this growth can be slowed, we explore four scenarios for Chinese buildings, ranging from a high-energy-demand scenario with no new energy policies to lowest energy demand under a techno-economic-potential scenario that assumes full deployment of cost-effective efficient and renewable technologies by 2050. We show that, in the high energy demand scenario, building energy demand has an average annual growth rate of about 2.8%, with slower growth rates in the other three scenarios. In all scenarios, CO2 emissions grow slower than energy, with building CO2 peaking around 2045 in the high energy demand scenario, and as early as 2030 in the techno-economic-potential scenario. We show that although various technological solutions, systems and practices can be very effective in minimizing building energy use, rigorous policies are needed to overcome multiple implementation barriers
Transonic flow in a converging-diverging nozzle Final report
Transonic equations of motion for convergent-divergent nozzl
<a comparative study of the evolution of enzymes and nucleic acids< semi-annual status report, nov. 1, 1964 - apr. 30, 1965
Lactic dehydrogenases and protein immunochemicals in vertebrate evolution - irradiation of nucleic acid
Item program manual, Fortran IV version
Orbit calculation using Encke perturbation method and Fortran IV programmin
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