9,431 research outputs found
Study to determine dielectric properties of sandstone, shale, coal, and slate
Triplicate dielectric constant and loss tangent measurements on samples of sandstone, shale, coal, and slate were performed. Each of the three necessary configurations of the coal material was sampled to obtain measurements, with each sample machined parallel to the coal layering orientation. The coal samples were machined perpendicular to the coal layering and measured. They were conditioned at 100% humidity and at room temperature and remeasured; then conditioned in an elevated environment, and remeasured for dielectric properties. The coal data appear to remain relatively constant over the microwave frequency region. At the Ghz frequencies, the relative dielectric constant of coal is slightly higher for the E-field parallel to the layers than for the perpendicular case
Improved liquid-level sensor for cryogenics
Liquid-level indicator, consisting of a diode heated by a resistor, allows simultaneous use of two or three of the liquids nitrogen, hydrogen, and helium. Operation depends on strong temperature-dependence of the forward resistance of a germanium diode and the difference between liquid and vapor in heat-transfer properties
Characterization of High Proper Motion Objects from the Wide-field Infrared Survey Explorer
We present an analysis of high proper motion objects that we have found in a
recent study and in this work with multi-epoch astrometry from the Wide-field
Infrared Survey Explorer (WISE). Using photometry and proper motions from 2MASS
and WISE, we have identified the members of this sample that are likely to be
late type, nearby, or metal poor. We have performed optical and near-infrared
spectroscopy on 41 objects, from which we measure spectral types that range
from M4-T2.5. This sample includes 11 blue L dwarfs and five subdwarfs; the
latter were also classified as such in the recent study by Kirkpatrick and
coworkers. Based on their spectral types and photometry, several of our
spectroscopic targets may have distances of <20 pc with the closest at ~12 pc.
The tangential velocities implied by the spectrophotometric distances and
proper motions indicate that four of the five subdwarfs are probably members of
the Galactic halo while several other objects, including the early-T dwarf WISE
J210529.08-623558.7, may belong to the thick disk.Comment: Astrophysical Journal, in pres
The potential impact on Florida-based marina and boating industries of a post-embargo Cuba: an analysis of geographic, physical, policy and industry trends
The information in this Technical Paper addresses the future of the US-Cuban marina and recreational
boating industries from the geographic, physical, policy making and economic perspectives for a post-embargo Cuba.
Each individual paper builds on the presentations made at the workshop, the information obtained in the subsequent trip
to Cuba and presents in detailed form information which we hope is useful to all readers. (147pp.
Vortex -- Kink Interaction and Capillary Waves in a Vector Superfluid
Interaction of a vortex in a circularly polarized superfluid component of a
2d complex vector field with the phase boundary between superfluid phases with
opposite signs of polarization leads to a resonant excitation of a
``capillary'' wave on the boundary. This leads to energy losses by the
vortex--image pair that has to cause its eventual annihilation.Comment: LaTeX 7 pages, no figure
Investigation of metal flow in bridge die extrusion of Alloy 6063 and subsequent effect on surface quality and weld seam integrity
This paper describes a detailed study of tube extrusion by simulation using finite element method (FEM). The finite element model used one-sixth of symmetry. The extrusion load, emperature evolution and metal flow were predicted. Innovative methods, combining both grid and surface tools, were used to define in detail the flow of material. These showed clearly the inner and outer surface formation mechanisms of the tube extrusion. The seam weld, an important quality indicator, was also evaluated by selecting an appropriate criterion
Proceedings of a seminar on Future Directions for New Zealand Lamb Marketing
A seminar on lamb marketing was
organised to provide a forum for discussion of this important
issue, as New Zealand faces significant changes in the
lamb marketing environment. The increasing importance of
new lamb markets, especially in the Middle East, the
importance of the North American market and the increasing
fragility of the United Kingdom lamb market, make such
discussion very timely. In addition, the market requirement
for lambs with a lower fat content has meant that
lamb grading standards have been more rigorously set and
substantial price schedule penalties have been imposed
for over fatness.
Increasing production, processing and transportation
costs have meant that the farmers share, of the market
price for lamb, has fallen. This means that it has become
even more important to achieve the maximum possible market
return. The achievement of this target must depend on
the markets available, the type of marketing activity undertaken in those markets and the structure of the
industry supporting the marketing effort. The optimum
results may not be available based on the present industry
structure and approach and it was therefore considered
appropriate that alternatives be reviewed and examined
with a view to the future. Includes full text of the papers: Hilgendorf, C. New Zealand lamb marketing: the past and present; Cullwick, T.D.C. The need for a global marketing strategy for lamb and lamb products
Relationships between lower-body muscle structure and, lower-body strength, explosiveness and eccentric leg stiffness in adolescent athletes
The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a counter-movement jump (CMJ) and squat jump (SJ), and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23) and female (n = 7) surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg) undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isomet-ric mid-thigh pull (IMTP). In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73) were identified be-tween the thickness of the vastus lateralis (VL) and lateral gas-trocnemius (LG) muscles, and VL pennation angle and; peak force (PF) in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59) were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59) also present with IMTP PF. These results suggest that greater thick-ness of the VL and LG were related to improved maximal dy-namic and isometric strength, likely due to increased hypertro-phy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle
Physiological Profile of Male Competitive and Recreational Surfers
Surfing consists of both high- and low-intensity paddling of varying durations, using both the aerobic and anaerobic systems. Surf-specific physiological studies lack adequate group sample sizes, and V[Combining Dot Above]O2peak values are yet to determine the differences between competitive and recreational surfers. The purpose of this study was therefore to provide a comprehensive physiological profile of both recreational and competitive surfers. This multisite study involved 62 male surfers, recreational (n = 47) and competitive (n = 15). Anthropometric measurements were conducted followed by dual-energy x-ray absorptiometry, anaerobic testing and finally aerobic testing. V[Combining Dot Above]O2peak was significantly greater in competitive surfers than in recreational surfers (M = 40.71 ± 3.28 vs. 31.25 ± 6.31 ml·kg·min, p \u3c 0.001). This was also paralleled for anaerobic power (M = 303.93 vs. 264.58 W) for competitive surfers. Arm span and lean total muscle mass was significantly (p ≤ 0.01) correlated with key performance variables (V[Combining Dot Above]O2peak and anaerobic power). No significant (p ≥ 0.05) correlations were revealed between season rank and each of the variables of interest (V[Combining Dot Above]O2peak and anaerobic power). Key performance variables (V[Combining Dot Above]O2peak and anaerobic power) are significantly higher in competitive surfers, indicating that this is both an adaptation and requirement in this cohort. This battery of physiological tests could be used as a screening tool to identify an athlete\u27s weaknesses or strengths. Coaches and clinicians could then select appropriate training regimes to address weaknesses
The Youthful Appearance of the 2003 EL61 Collisional Family
We present new solar phase curve observations of the 2003 EL61 collisional
family showing that all the members have light-scattering properties similar to
the bright icy satellites and dwarf planets. Compared to other Kuiper Belt
objects, the five family members we observe (2003 EL61, 2002 TX300, 2003 OP32,
2005 RR43, and 1995 SM55) have conspicuously neutral color (V-I = 0.6-0.8 mag)
and flat phase curves at small phase angles (phase coefficients of 0.0 - 0.1
mag deg-1). Comparing the phase curves we observe for other icy Kuiper Belt
objects to the phase curves of icy satellites, we find that the flat phase
curves of the 2003 EL61 family are an indication they have high albedo surfaces
coated with fresh ice in the last ~100 Myr. We examine possible resurfacing
processes and find none that are plausible. To avoid the influence of cosmic
radiation that darkens and reddens most icy surfaces on times scales > ~100
Myr, the family members must be unusually depleted in carbon, or else the
collision that created the family occurred so recently that the parent body and
fragments have not had time to darken. We also find a rotation period of 4.845
(+/- 0.003) h with amplitude 0.26 (+/- 0.04) mags for 2003 OP32.Comment: 12 pages, 3 tables, 4 figure
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