Apparatus for performing high-temperature fiber push-out testing

The apparatus disclosed in the present invention measures the force at which a fiber resist the motion of an indenter driven at constant speed. This apparatus conducts these test in a vacuum of about 10(exp -6) tort and at temperatures up to 1100 C. Temperature and vacuum environment are maintained while controlling indenter motion, sample position, and providing magnified visual inspection during the test

Evolution of the ring current energy during May 2-4, 1998 magnetic storm

We study the evolution of the ring current energy density during May 2-4, 1998 storm event as measured by Polar CAMMICE/MICS instrument and modelled by proton tracing in the guiding center approximation. Particle data from Polar shows that during the storm main phase protons with medium energies (20-80 keV) contribute more to the total ring current energy than the high energy protons (80-200 keV) whereas during the recovery phase high energies dominate. We trace protons with arbitrary pitch angles numerically in the guiding center approximation taking into account charge-exchange losses. Tracing is performed in the large-scale and smaller-scale time-dependent magnetic and electric field models. We model the substorm activity by several electric field pulses at times of the substorm onsets. It is shown that impulsive electric fields associated with substorms are effective in the proton transport and energization to higher energies more than 100 keV in the storm time ring current

Zero Temperature Chiral Phase Transition in (2+1)-Dimensional QED with a Chern-Simons Term

We investigate the zero temperature chiral phase transition in (2+1)-dimensional QED in the presence of a Chern-Simons term, changing the number of fermion flavors. In the symmetric phase, there are no light degrees of freedom even at the critical point. Unlike the case without a Chern-Simons term, the phase transition is first-order.Comment: 7 pages, RevTeX, no figure

Phase structure of the Higgs-Yukawa systems with chirally invariant lattice fermion actions

We develop analytical technique for examining phase structure of $Z_2$, $U(1)$, and $SU(2)$ lattice Higgs-Yukawa systems with radially frozen Higgs fields and chirally invariant lattice fermion actions. The method is based on variational mean field approximation. We analyse phase diagrams of such systems with different forms of lattice fermion actions and demonstrate that it crucially depends both on the symmetry group and on the form of the action. We discuss location in the diagrams of possible non-trivial fixed points relevant to continuum physics, and argue that the candidates can exist only in $Z_2$ system with SLAC action and $U(1)$ systems with naive and SLAC actions. [Note: By a product, missing term in Eq. (3.5) of hep-lat/9309010 is reconstructed, that, however, affects only the result of Sect. 4.3 (Fig. 3) of that reference (cf. Fig. 2(c) of this paper).]Comment: KEK-TH-390, KYUSHU-HET-17, 34 pages (harvmac) including 17 figures (appended in postscript format with uuencoded tar file).(PostScript Files are fixed.

Lattice Boltzmann modeling and simulation of forced-convection boiling on a cylinder

When boiling occurs in a liquid flow field, the phenomenon is known as forced-convection boiling. We numerically investigate such a boiling system on a cylinder in a flow at saturated conditions. To deal with the complicated liquid–vapor phase-change phenomenon, we develop a numerical scheme based on the pseudopotential lattice Boltzmann method (LBM). The collision stage is performed in the space of central moments (CMs) to enhance numerical stability for high Reynolds numbers. The adopted forcing scheme, consistent with the CM-based LBM, leads to a concise yet robust algorithm. Furthermore, additional terms required to ensure thermodynamic consistency are derived in a CM framework. The effectiveness of the present scheme is successfully tested against a series of boiling processes, including nucleation, growth, and departure of a vapor bubble for Reynolds numbers varying between 30 and 30 000. Our CM-based LBM can reproduce all the boiling regimes, i.e., nucleate boiling, transition boiling, and film boiling, without any artificial input such as initial vapor phase. We find that the typical boiling curve, also known as the Nukiyama curve, appears even though the focused system is not the pool boiling but the forced-convection system. Also, our simulations support experimental observations of intermittent direct solid–liquid contact even in the film-boiling regime. Finally, we provide quantitative comparison with the semi-empirical correlations for the forced-convection film boiling on a cylinder on the Nu-Ja diagram

Pressure Evolution of a Field Induced Fermi Surface Reconstruction and of the Neel Critical Field in CeIn3

We report high-pressure skin depth measurements on the heavy fermion material CeIn3 in magnetic fields up to 64 T using a self-resonant tank circuit based on a tunnel diode oscillator. At ambient pressure, an anomaly in the skin depth is seen at 45 T. The field where this anomaly occurs decreases with applied pressure until approximately 1.0 GPa, where it begins to increase before merging with the antiferromagnetic phase boundary. Possible origins for this transport anomaly are explored in terms of a Fermi surface reconstruction. The critical magnetic field at which the Neel ordered phase is suppressed is also mapped as a function of pressure and extrapolates to the previous ambient pressure measurements at high magnetic fields and high pressure measurements at zero magnetic field.Comment: 15 pages, 5 figure

Crustal partial melting on Vesta: evidence from highly metamorphosed eucrites

We have performed a mineralogical and geochemical study of eight metamorphosed basaltic eucrites. These are classified into granulitic eucrites and type 4-7 eucrites on the basis of their textures and pyroxene mineralogy, and display mineralogical evidence for high temperature metamorphism, including partial melting. In particular, rare earth element (REE) patterns of a number of the eucrites studied show varying degrees of light REE depletion due to partial melting, with subsequent melt extraction. A simple correlation between metamorphic grade, as deduced from pyroxene mineralogy, and the degree of light REE depletion was not detected. This can be explained by the fact that homogenization, exsolution and inversion of pigeonite would have required prolonged heating at moderate temperatures (~800-1000 °C), whereas partial melting would have taken place over a short time interval where temperatures exceeded that of the solidus. The eucrites studied therefore record a two stage thermal regime consisting of short, high temperature reheating events superimposed on long duration global crustal metamorphism. The short reheating events may have been caused by impact events and/or intrusions of hot magmas. The results of this study demonstrate that the thermal history of eucritic crust was more complex than can be explained by a simple burial model alone. In particular, the origin of Stannern trend eucrites requires contamination of Main-Group magmas by partial melts extracted from residual eucrites

Ion-dispersion and rapid electron fluctuations in the cusp: a case study

We present results from co-ordinated measurements with the low altitude REIMEI satellite and the ESR (EISCAT Svalbard Radar), together with other ground-based instruments carried out in February 2006. The results mainly relate to the dayside cusp where clear signatures of so-called ion-dispersion are seen in the satellite data. The cusp ion-dispersion is important for helping to understand the temporal and spatial structure of magnetopause reconnection. Whenever a satellite crosses boundaries of flux tubes or convection cells, cusp structures such as ion-dispersion will always be encountered. In our case we observed 3 distinct steps in the ion energy, but it includes at least 2 more steps as well, which we interpret as temporal features in relation to pulsed reconnection at the magnetopause. In addition, fast variations of the electron flux and energy occurring during these events have been studied in detail. The variations of the electron population, if interpreted as structures crossed by the REIMEI satellite, would map near the magnetopause to similar features as observed previously with the Cluster satellites. These were explained as Alfvén waves originating from an X-line of magnetic reconnection

Buildup of the ring current during periodic loading‐unloading cycles in the magnetotail driven by steady southward interplanetary magnetic field

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95239/1/jgra18825.pd