45,730 research outputs found
Computer program determines thermal environment and temperature history of lunar orbiting space vehicles
Program computes the thermal environment of a spacecraft in a lunar orbit. The quantities determined include the incident flux /solar and lunar emitted radiation/, total radiation absorbed by a surface, and the resulting surface temperature as a function of time and orbital position
Modeling radiation in particle clouds: On the importance of inter-particle radiation for pulverized solid fuel combustion
The importance of inter-particle radiation for clusters of gray and diffuse
particles is investigated. The radiative cooling of each individual particle is
found to vary strongly with its position in the cluster, and a mean radiative
particle cooling term is proposed for single particle simulations of particle
clusters or for high detail simulation, like Direct Numerical Simulations of
small sub-volumes of large clusters of particles. Radiative cooling is shown to
be important both for furnaces for coal gasification and coal combustion.
Broadening the particle size distribution is found to have just a minor effect
on the radiative particle cooling. This is particularly the case for large and
dense particle clusters where there is essentially no effect of size
distribution broadening at all. For smaller and more dilute particle clusters,
the effect of distribution broadening is clear but still not dominant
Herding Cats: Improving Law School Teaching
What makes a good law teacher? Is excellence in teaching largely a matter of intellectual brilliance, of superior organization and delivery of material, of friendliness and fairness to one\u27s students? Or does it have more to do with style, with stage presence, with the ability to engage an audience in the act of reflective and spontaneous thinking?
While the question of how to define and evaluate teaching necessarily bedevils deans and tenure committees who must make personnel decisions, the focus on defining the competent teacher has obscured from faculty attention the more fundamental question: how can we implement a system to improve faculty performance across the board? It is this question that law schools around the country have not adequately addressed.
Three years ago, the faculty of Franklin Pierce Law Center adopted a program to improve our classroom teaching. This article describes and evaluates that program, in which all three authors played a role
Archetypal analysis of galaxy spectra
Archetypal analysis represents each individual member of a set of data
vectors as a mixture (a constrained linear combination) of the pure types or
archetypes of the data set. The archetypes are themselves required to be
mixtures of the data vectors. Archetypal analysis may be particularly useful in
analysing data sets comprising galaxy spectra, since each spectrum is,
presumably, a superposition of the emission from the various stellar
populations, nebular emissions and nuclear activity making up that galaxy, and
each of these emission sources corresponds to a potential archetype of the
entire data set. We demonstrate archetypal analysis using sets of composite
synthetic galaxy spectra, showing that the method promises to be an effective
and efficient way to classify spectra. We show that archetypal analysis is
robust in the presence of various types of noise.Comment: 6 pages, 5 figures, 1 style-file. Accepted for publication by MNRA
Human factors analysis of workstation design: Earth Radiation Budget Satellite Mission Operations Room
A human factors analysis addressed three related yet distinct issues within the area of workstation design for the Earth Radiation Budget Satellite (ERBS) mission operation room (MOR). The first issue, physical layout of the MOR, received the most intensive effort. It involved the positioning of clusters of equipment within the physical dimensions of the ERBS MOR. The second issue for analysis was comprised of several environmental concerns, such as lighting, furniture, and heating and ventilation systems. The third issue was component arrangement, involving the physical arrangement of individual components within clusters of consoles, e.g., a communications panel
Panel summary of recommendations
The following Space Station internal contamination topics were addressed: past flight experience (Skylab and Spacelab missions); present flight activities (Spacelabs and Soviet Space Station Mir); future activities (materials science and life science experiments); Space Station capabilities (PPMS, FMS, ECLSS, and U.S. Laboratory overview); manned systems/crew safety; internal contamination detection; contamination control - stowage and handling; and contamination control - waste gas processing. Space Station design assumptions are discussed. Issues and concerns are discussed as they relate to (1) policy and management, (2) subsystem design, (3) experiment design, and (4) internal contamination detection and control. The recommendations generated are summarized
Growth of ice particle mass and projected area during riming
There is a long-standing challenge in cloud and climate models to simulate
the process of ice particle riming realistically, partly due to the
unrealistic parameterization of the growth of ice particle mass (m)
and projected area (A) during riming. This study addresses this
problem, utilizing ground-based measurements of m and ice particle
maximum dimension (D) as well as theory to formulate simple
expressions describing the dependence of m and A on
riming. It was observed that β in the m − D power law
m  = α Dβ appears independent of riming during
the phase 1 (before the formation of graupel), with α
accounting for the ice particle mass increase due to riming. This
semi-empirical approach accounts for the degree of riming and renders a
gradual and smooth ice particle growth process from unrimed ice particles to
graupel, and thus avoids discontinuities in m and A during
accretional growth. Once the graupel with quasi-spherical shape forms,
D increases with an increase in m and A (phase 2
of riming). The treatment for riming is explicit, and includes the
parameterization of the ice crystal–cloud droplet collision efficiency
(Ec) for hexagonal columns and plates using hydrodynamic
theory. In particular, Ec for cloud droplet diameters less
than 10 µm are estimated, and under some conditions observed in mixed-phase clouds, these droplets can account for roughly half of the mass growth
rate from riming. These physically meaningful yet simple methods can be used
in models to improve the riming process
The Continuing Leverage of Releasing Authorities: Findings from a National Survey
The Robina Institute of Criminal Law and Criminal Justice launched a national survey of releasing authorities in March 2015 to each state, and the U.S. Parole Commission. The importance of the survey was underscored by an endorsement from the Association of Paroling Authorities International (APAI). We are pleased to present the results from this important survey here. This is the first comprehensive survey of parole boards completed in nearly 10 years. Its findings provide a rich database for better understanding the policy and practice of paroling authorities. The last survey to be conducted of paroling authorities was in 2007/2008.The current report offers an expansion and update of previous surveys. The results summarized throughout the report offer a timely resource for paroling authorities, correctional policy-makers and practitioners, legislators, and those with a public policy interest in sentencing and criminal justice operations. It is our hope that the document and its findings provide key justice system and other stakeholders with an incisive snapshot of the work of paroling authorities across the country in a manner that contributes to a larger conversation about sound and effective parole release and revocation practices.The completion of this comprehensive survey and the reporting of its findings offers a timely and invaluable resource for releasing authorities. It provides them and other key justice system stakeholders with a comparative understanding of their colleagues' work across the nation, and contributes to a larger conversation pertaining to effective parole release and revocation practices
Total syntheses of conformationally-locked difluorinated pentopyranose analogues and a pentopyranosyl phosphate mimetic
Trifluoroethanol has been elaborated, via a telescoped sequence involving a metalated difluoroenol, a difluoroallylic alcohol, [2,3]-Wittig rearrangement, and ultimately an RCM reaction and requiring minimal intermediate purification, to a number of cyclooctenone intermediates. Epoxidation of these intermediates followed by transannular ring opening or dihydroxylation, then transannular hemiacetalization delivers novel bicyclic analogues of pentopyranoses, which were elaborated (in one case) to an analogue of a glycosyl phosphate
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