19,576 research outputs found
Flow field prediction and analysis study for project RAM B3 Final report
Flow field properties in shock layer surrounding Ram B3 vehicl
High temperature polyimide foams for shuttle upper surface thermal insulation
Polyimide foams developed by Monsanto Company were examined for use as upper surface space shuttle thermal insulation. It was found that postcured polyimide foams having a density of 64 kg/cu m (4 lb/cu ft) had acceptable physical properties up to and exceeding 700 K (800 F). Physical tests included cyclic heating and cooling in vacuum, weight and dimensional stability, mechanical strength and impact resistance, acoustic loading and thermal conductivity. Molding and newly developed postcuring procedures were defined
Some Molds Associated with Meat in Cold Storage Lockers in Iowa
In the past few years throughout the United States cold storage locker plants have been introduced as a new industry, offering their services to the public as storage depots for perishable foods, particularly meats. The wide-spread popularity of this industry is attested by the existence of approximately two thousand cold storage locker plants in the United States of which two hundred are located in Iowa. Over one hundred of these plants in Iowa were introduced during the past year, and there is every indication that their number win continue to increase
Parametrizing the time-variation of the "surface term" of stellar p-mode frequencies: application to helioseismic data
The solar-cyle variation of acoustic mode frequencies has a frequency
dependence related to the inverse mode inertia. The discrepancy between model
predictions and measured oscillation frequencies for solar and solar-type
stellar acoustic modes includes a significant frequency-dependent term known as
the surface term that is also related to the inverse mode inertia. We
parametrize both the surface term and the frequency variations for low-degree
solar data from Birmingham Solar-Oscillations Network (BiSON) and medium-degree
data from the Global Oscillations Network Group (GONG) using the mode inertia
together with cubic and inverse frequency terms. We find that for the central
frequency of rotationally split multiplets the cubic term dominates both the
average surface term and the temporal variation, but for the medium-degree case
the inverse term improves the fit to the temporal variation. We also examine
the variation of the even-order splitting coefficients for the medium-degree
data and find that, as for the central frequency, the latitude-dependent
frequency variation, which reflects the changing latitudinal distribution of
magnetic activity over the solar cycle, can be described by the combination of
a cubic and an inverse function of frequency scaled by inverse mode inertia.
The results suggest that this simple parametrization could be used to assess
the activity-related frequency variation in solar-like asteroseismic targets.Comment: 13 pages, 11 figures. Accepted by MNRAS 13 October 201
‘‘There’s so much more to it than what I initially thought’’: Stepping into researchers’ shoes with a class activity in a first year psychology survey course
In psychology, it is widely agreed that research methods, although central to the discipline, are particularly challenging to learn and teach, particularly at introductory level. This pilot study explored the potential of embedding a student-conducted research activity in a one-semester undergraduate Introduction to Psychology survey course, with the aims of (a) engaging students with the topic of research methods; (b) developing students’ comprehension and application of research methods concepts; and (c) building students’ ability to link research with theory. The research activity explored shoe ownership, examining gender differences and relationships with age, and linking to theories of gender difference and of consumer identity. The process of carrying out the research and reflecting on it created a contextualized, active learning environment in which students themselves raised many issues that research methods lectures seek to cover. Students also wrote richer assignments than standard first year mid-term essay
Non-existence of Skyrmion-Skyrmion and Skyrmion-anti-Skyrmion static equilibria
We consider classical static Skyrmion-anti-Skyrmion and Skyrmion-Skyrmion
configurations, symmetric with respect to a reflection plane, or symmetric up
to a -parity transformation respectively. We show that the stress tensor
component completely normal to the reflection plane, and hence its integral
over the plane, is negative definite or positive definite respectively.
Classical Skyrmions always repel classical Skyrmions and classical Skyrmions
always attract classical anti-Skyrmions and thus no static equilibrium, whether
stable or unstable, is possible in either case. No other symmetry assumption is
made and so our results also apply to multi-Skyrmion configurations. Our
results are consistent with existing analyses of Skyrmion forces at large
separation, and with numerical results on Skymion-anti-Skyrmion configurations
in the literature which admit a different reflection symmetry. They also hold
for the massive Skyrme model. We also point out that reflection symmetric
self-gravitating Skyrmions or black holes with Skyrmion hair cannot rest in
symmetric equilibrium with self-gravitating anti-Skyrmions.Comment: v2 Typos corrected, refs added. v3 Journal versio
Results from investigations in three NASA/LaRC hypersonic wind tunnels on a .004 scale model space shuttle orbiter (model 13P-O) to determine real gas effects (LA78, LA87, LA88)
Results from tests in the NASA/CF4, 20 inch Mach 6 and the 22 inch Helium Tunnel consist of pressure measurements on the lower surfaces of the Rockwell Space Shuttle Orbiter. All data are in absolute pressures. Data were recorded with the model at a Mach number of 6 and 20 at angles of 10 deg to 30 deg
The Sun in transition? Persistence of near-surface structural changes through Cycle 24
We examine the frequency shifts in low-degree helioseismic modes from the
Birmingham Solar-Oscillations Network (BiSON) covering the period from 1985 -
2016, and compare them with a number of global activity proxies well as a
latitudinally-resolved magnetic index. As well as looking at frequency shifts
in different frequency bands, we look at a parametrization of the shift as a
cubic function of frequency. While the shifts in the medium- and highfrequency
bands are very well correlated with all of the activity indices (with the best
correlation being with the 10.7 cm radio flux), we confirm earlier findings
that there appears to have been a change in the frequency response to activity
during solar cycle 23, and the low frequency shifts are less correlated with
activity in the last two cycles than they were in Cycle 22. At the same time,
the more recent cycles show a slight increase in their sensitivity to activity
levels at medium and higher frequencies, perhaps because a greater proportion
of activity is composed of weaker or more ephemeral regions. This lends weight
to the speculation that a fundamental change in the nature of the solar dynamo
may be in progress.Comment: 9 pages, 6 figures. Accepted by MNRAS 24 May 201
Analysis of B-> \phi K Decays in QCD Factorization
We analyze the decay within the framework of QCD-improved
factorization. We found that although the twist-3 kaon distribution amplitude
dominates the spectator interactions, it will suppress the decay rates
slightly. The weak annihilation diagrams induced by penguin
operators, which are formally power-suppressed by order , are
chirally and logarithmically enhanced. Therefore, these annihilation
contributions are not subject to helicity suppression and can be sizable. The
predicted branching ratio of is in
the absence of annihilation contributions and it becomes
when annihilation effects are taken into
account. The prediction is consistent with CLEO and BaBar data but smaller than
the BELLE result.Comment: 13 pages, 3 figures. A major change for the presentation of
branching-ratio predictions. Experimental data are update
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