2,675 research outputs found
Research into the feasibility of thin metal and oxide film capacitors
Feasibility of thin metal and oxide film capacitor
Research into the feasibility of thin metal and oxide film capacitors Interim scientific report
Feasibility of thin metal and oxide film capacitor
Two-fluid and magnetohydrodynamic modelling of magnetic reconnection in the MAST spherical tokamak and the solar corona
Twisted magnetic flux ropes are ubiquitous in space and laboratory plasmas,
and the merging of such flux ropes through magnetic reconnection is an
important mechanism for restructuring magnetic fields and releasing free
magnetic energy. The merging-compression scenario is one possible start up
scheme for spherical tokamaks, which has been used on the Mega Amp Spherical
Tokamak MAST. Two current-carrying plasma rings, or flux ropes, approach each
other through the mutual attraction of their like currents, and merge, through
magnetic reconnection, into a single plasma torus, with substantial plasma
heating. 2D resistive MHD and Hall MHD simulations of this process are
reported, and new results for the temperature distribution of ions and
electrons are presented. A model of the based on relaxation theory is also
described, which is now extended to tight aspect ratio geometry. This model
allows prediction of the final merged state and the heating. The implications
of the relaxation model for heating of the solar corona are also discussed, and
a model of the merger of two or more twisted coronal flux ropes is presented,
allowing for different senses of twist
Effects of creep feeding and its interactions with other factors on the performance of meat goat kids and dams when managed on pasture
Creep feeding and its possible interactions with other influential factors (genetics, litter type, and sex) for weaning traits were studied in meat goat kids and their dams. Kids across 3 yr were creep fed (254 kids; 5 pens) or not creep fed (255 kids; 5 pens) from 30 to 90 d of age. Creep-fed kids had higher (P ≤ 0.05) preweaning average daily weight gain and weaning weights (113.1 ± 13.0 g/d; 15.0 ± 0.8 kg) than kids not creep fed (99.8 ± 13.1 g/d; 14.0 ± 0.8 kg). However, financial returns were not higher (P \u3e 0.05) for creep-fed kids compared with kids not creep fed. There was no difference (P \u3e 0.05) in kid conformation score or survival rates between the treatment groups. The only important interaction among kid traits was treatment × litter type (P \u3c 0.05) for FAMACHA scores. Within noncreep pens, single kids had lower (better; P \u3c 0.05) FAMACHA scores (2.9 ± 0.3) than twin kids (3.9 ± 0.3). There was no litter-type effect on FAMACHA scores for kids within the creep feed pens. Dams of the creep-fed (n = 175) and noncreep (n = 178) kids were also evaluated. Treatment did not affect (P \u3e 0.05) litter weights, dam weight change, gross revenue for weaned litters, or fecal egg counts. Treatment interacted with litter type (P \u3c 0.05) to effect packed cell volume (PCV). In the noncreep group, dams raising singles had higher (better; P \u3c 0.05) PCV (18.7 ± 1.3%) than dams rearing twin kids (15.7 ± 1.3%). The litter-type effect on dam PCV was not evident (P \u3e 0.05) in the creep-fed group. Creep feeding improved some kid growth traits but did not improve dam traits or financial returns. Interactions of creep treatment with other factors were minimal for doe-kid traits
The atomic structure of large-angle grain boundaries and in and their transport properties
We present the results of a computer simulation of the atomic structures of
large-angle symmetrical tilt grain boundaries (GBs) (misorientation
angles \q{36.87}{^{\circ}} and \q{53.13}{^{\circ}}),
(misorientation angles \q{22.62}{^{\circ}} and \q{67.38}{^{\circ}}). The
critical strain level criterion (phenomenological criterion)
of Chisholm and Pennycook is applied to the computer simulation data to
estimate the thickness of the nonsuperconducting layer enveloping
the grain boundaries. The is estimated also by a bond-valence-sum
analysis. We propose that the phenomenological criterion is caused by the
change of the bond lengths and valence of atoms in the GB structure on the
atomic level. The macro- and micro- approaches become consistent if the
is greater than in earlier papers. It is predicted that the
symmetrical tilt GB \theta = \q{53.13}{^{\circ}} should demonstrate
a largest critical current across the boundary.Comment: 10 pages, 2 figure
Induction of Germinal Centers by MMTV Encoded Superantigen on B Cells
It has not been established whether an endogenous superantigen (SAg) expressed on B cells
can induce germinal centers (GCs). An interesting model is that of mammary tumor virus
encoded viral SAgs, which induce vigorous T cell proliferation and are predominantly
expressed on activated B cells. We have used this model to analyze the possibility that direct
stimulation of Mtv7+ DBA/2 B cells by vSAg-responsive (Vβ6+) BALB/c T cells can give
rise to GCs. Injection of BALB/c SCID mice iv with 2 × 106 DBA/2 B cells, together with
LPS, followed by 2 × 106 BALB/c T cells induces numerous large splenic GCs within 3–5
days. The GCs are still large on day 7, but are very much reduced by day 10. B cell activation
with LPS is needed for this effect. These GCs form in spite of the apparent absence of follicular
dendritic cells (FDCs) as judged by staining for several FDC surface markers. Control
mice receiving either BALB/c T or DBA/2 B cells + LPS alone or DBA/2 T + B cells + LPS
fail to exhibit any GCs on days 3–7. Numerous small clusters of PNA+ cells, but few large
GCs are observed when TNF-R(p55)-Ig is also injected, whereas LTβR-Ig treatment impeded
the formation of aggregations of these cells even further, leaving scattered PNA+ single cells
and very small clumps throughout the white pulp of the spleens. Anti-TNFα had no effect.
These results suggest that endogenous vSAg mediated GC formation is independent of antigen
trapping by FDCs
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Pass-through core measurements of magnetic susceptibility and natural gamma ray, New Jersey Coastal Plain
We measured magnetic susceptibility (MS) and core gamma radiation (CGR) on 3162 ft (963.9 m) of core recovered by the New Jersey Coastal Plain Drilling Project (Ocean Drilling Program Leg 150X) at Island Beach, Atlantic City, and Cape May, New Jersey. Integration of core lithology, core/log (MS and CGR), and downhole gamma-ray (DGR) log studies have (1) documented the core/log expression of previously determined unconformities; (2) shown that MS is a proxy for glauconite percent in the New Jersey Coastal Plain; (3) illustrated a major change in sedimentation from shelfal glauconite evidenced by very high MS values to deltaic deposition with low MS values in the earliest Miocene (ca. 22 Ma); (4) shown that comparison of MS and CGR with DGR can be used to resolve discrepancies in depth between downhole logs and cores; and (5) shown that the CGR detects some zones noted in the lithology (e.g., phosphate rich zones) that are not resolved in the DGR
One-Step Processing of Spinel Ferrites via the High-Energy Ball Milling of Binary Oxides
MnZn ferrites have been produced via the high-energy ball milling of binary oxide precursors. The milled ferrites have a nonequilibrium cation site distribution, with an unusually high population of Zn cations on the octahedral sites. The particle size distribution drops precipitously with milling time from 60±1 to ∼14±1 nm at 10 h, but increases to 18.5±1 nm after long durations (20–40 h) concurrent with the formation of nearly pure ferrite. A 1 h anneal at 673 K facilitates a redistribution of cations to their near equilibrium sites. This processing approach circumvents the need for deleterious high-temperature heat treatments that often lead to nonstoichiometries in the resulting ferrites
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Preliminary site report for the 2005 ICDP-USGS deep corehole in the Chesapeake Bay impact crater
First report for the ICDP-USGS 1.7-km-deep corehole drilled into the central part of the Chesapeake Bay impact crater during 2005
Simulations of core convection in rotating A-type stars: Differential rotation and overshooting
We present the results of 3--D simulations of core convection within A-type
stars of 2 solar masses, at a range of rotation rates. We consider the inner
30% by radius of such stars, thereby encompassing the convective core and some
of the surrounding radiative envelope. We utilize our anelastic spherical
harmonic (ASH) code, which solves the compressible Navier-Stokes equations in
the anelastic approximation, to examine highly nonlinear flows that can span
multiple scale heights. The cores of these stars are found to rotate
differentially, with central cylindrical regions of strikingly slow rotation
achieved in our simulations of stars whose convective Rossby number (R_{oc}) is
less than unity. Such differential rotation results from the redistribution of
angular momentum by the nonlinear convection that strongly senses the overall
rotation of the star. Penetrative convective motions extend into the overlying
radiative zone, yielding a prolate shape (aligned with the rotation axis) to
the central region in which nearly adiabatic stratification is achieved. This
is further surrounded by a region of overshooting motions, the extent of which
is greater at the equator than at the poles, yielding an overall spherical
shape to the domain experiencing at least some convective mixing. We assess the
overshooting achieved as the stability of the radiative exterior is varied, and
the weak circulations that result in that exterior. The convective plumes serve
to excite gravity waves in the radiative envelope, ranging from localized
ripples of many scales to some remarkable global resonances.Comment: 48 pages, 16 figures, some color. Accepted to Astrophys. J. Color
figures compressed with appreciable loss of quality; a PDF of the paper with
better figures is available at
http://lcd-www.colorado.edu/~brownim/core_convectsep24.pd
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