1,361 research outputs found
A Wireless Double Planar Coil Sensor Arrangement for Monitoring Capacitance Changes Due to Water Uptake Embedded in a Thin Fiber-reinforced Composite
AbstractA wireless, near-field coupled sensor based on two planar spiral coils embedded in a thin fiber-reinforced composite material is presented. The measurement effect exploits the fact that penetrating water changes the effective dielectric permittivity in the volume surrounding the planar coils. This leads to an increase of the sensor self-capacitance and to a decrease of the sensor self-resonant frequency. The sensor targets applications in which non tactile, in-situ monitoring of water uptake, within a confined volume of material, is of interest. In order to describe the general electric behavior a circuit model, considering the sensor and an inductively coupled detection coil, has been developed and verified. An analytic expression for the resonance frequency was deduced. Sensor prototypes were integrated in a glass fiber polypropylene composite. Applied measurements demonstrate the resonance frequency change due to water entering and leaving the material during immersion and drying tests
Leptonic - and -decays: mass effects, polarization effects and radiative corrections
We calculate the radiative corrections to the unpolarized and the four
polarized spectrum and rate functions in the leptonic decay of a polarized into a polarized electron. The new feature of our calculation is that we
keep the mass of the final state electron finite which is mandatory if one
wants to investigate the threshold region of the decay. Analytical results are
given for the energy spectrum and the polar angle distribution of the final
state electron whose longitudinal and transverse polarization is calculated. We
also provide analytical results on the integrated spectrum functions. We
analyze the limit of our general results and investigate the
quality of the approximation. In the case we
discuss in some detail the role of the anomalous helicity flip
contribution of the final electron which survives the limit. The
results presented in this 0203048 also apply to the leptonic decays of
polarized -leptons for which we provide numerical results.Comment: 39 pages, 11 postscript figures added. Updated version. Four
references added. A few text improvements. Final version to appear in
Phys.Rev.
Facility for studying the effects of elevated carbon dioxide concentration and increased temperature on crops
The requirements for the experimental study of the effects of global climate change conditions on plants are outlined. A semi-controlled plant growth facility is described which allows the study of elevated CO2 and temperature, and their interaction on the growth of plants under radiation and temperature conditions similar to the field. During an experiment on winter wheat (cv. Mercia), which ran from December 1990 through to August 1991, the facility maintained mean daytime CO2 concentrations of 363 and 692 cm3 m-3 for targets of 350 and 700 cm3 m-3 respectively. Temperatures were set to follow outside ambient or outside ambient +4-degrees-C, and hourly means were within 0.5-degrees-C of the target for 92% of the time for target temperatures greater than 6-degrees-C. Total photosynthetically active radiation incident on the crop (solar radiation supplemented by artifical light with natural photoperiod) was 2% greater than the total measured outside over the same period
Non-perturbative Propagators, Running Coupling and Dynamical Quark Mass of Landau gauge QCD
The coupled system of renormalized Dyson-Schwinger equations for the quark,
gluon and ghost propagators of Landau gauge QCD is solved within truncation
schemes. These employ bare as well as non-perturbative ansaetze for the
vertices such that the running coupling as well as the quark mass function are
independent of the renormalization point. The one-loop anomalous dimensions of
all propagators are reproduced. Dynamical chiral symmetry breaking is found,
the dynamically generated quark mass agrees well with phenomenological values
and corresponding results from lattice calculations. The effects of unquenching
the system are small. In particular the infrared behavior of the ghost and
gluon dressing functions found in previous studies is almost unchanged as long
as the number of light flavors is smaller than four.Comment: 34 pages, 10 figures, version to be published by Phys. Rev.
Understanding Anthropological Understanding: for a merological anthropology
In this paper I argue for a merological anthropology in which ideas of ‘partiality’ and ‘practical adequacy’ provide a way out of the impasse of relativism which is implied by post-modernism and the related abandonment of a concern with ‘truth’. Ideas such as ‘aptness’ and ‘faithfulness’ enable us to re-establish empirical foundations without having to espouse a simple realism which has been rightly criticised. Ideas taken from ethnomethodology, particularly the way we bootstrap from ‘practical adequacy’ to ‘warrants for confidence’ point to a merological anthropology in which we recognize that we do not and cannot know everything, but that we can have reasons for being confident in the little we know
Slavnov-Taylor identities in Coulomb gauge Yang-Mills theory
The Slavnov-Taylor identities of Coulomb gauge Yang-Mills theory are derived
from the (standard, second order) functional formalism. It is shown how these
identities form closed sets from which one can in principle fully determine the
Green's functions involving the temporal component of the gauge field without
approximation, given appropriate input.Comment: 20 pages, no figure
Unusual thermal stability of a site-ordered MC60 rocksalt structure (M=K, Rb, or Cs)
X-ray diffraction and differential scanning calorimetry of MxC60, with x∼1 and M=K, Rb, or Cs, reveal an unusual T-dependent phase sequence. A low-symmetry ground state is found, while the high-T limit is an ordered rocksalt structure in which only the octahedral sites are occupied. The unusual high-T stability of this ordered phase is attributed to the entropy of molecular orientational disorder and/or thermal disorder of the alkali-metal ions within the octahedral sites. Unique to KxC60 with x1.4, we find at intermediate temperatures an fcc site-disordered lattice gas phase with random occupancy of tetrahedral and octahedral sites, which is thus isostructural with superconducting K3C60
STRAIN DIFFERENCES IN THE EXPRESSION OF THE EPA-1-RESTRICTING ELEMENT
Epa-1-specific cytotoxic T lymphocytes (CTL) lyse epidermal cells (EC) of different Epa-1 + H-2 k strains, such as AKR, CBA, C58, and RF, at different levels. We used an H-2K k -specific monoclonal antibody (mAb) to test the hypothesis that this phenomenon is due to differences in the H-2-restricting element. Initially, we established the specificity of this mAb for the Epa-1-restricting element by demonstrating its capacity to inhibit the lysis of CBA EC by Epa-1-specific CTL. We then used it as the probe in a cellular radioimmunoassay to quantify the expression of the restricting element by EC of different H-2 k strains. We found that C58 and RF EC bound significantly less of the mAb than did CBA EC. Although AKR also bound less of the mAb than did CBA EC, the difference was not statistically significant. To examine the generality of this phenomenon, we quantified the expression of K k antigens on spleen cells (SC) of the same four strains. We found that RF SC, but not AKR or C58 SC, bound significantly less of the K k mAb than did CBA SC. Thus, the differential CTL lysis of Epa-1 + EC of different strains probably reflects differences in expression of the H-2-restricting element rather than of the nominal antigen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75485/1/j.1744-313X.1987.tb00375.x.pd
Relation Between Chiral Susceptibility and Solutions of Gap Equation in Nambu--Jona-Lasinio Model
We study the solutions of the gap equation, the thermodynamic potential and
the chiral susceptibility in and beyond the chiral limit at finite chemical
potential in the Nambu--Jona-Lasinio (NJL) model. We give an explicit relation
between the chiral susceptibility and the thermodynamic potential in the NJL
model. We find that the chiral susceptibility is a quantity being able to
represent the furcation of the solutions of the gap equation and the
concavo-convexity of the thermodynamic potential in NJL model. It indicates
that the chiral susceptibility can identify the stable state and the
possibility of the chiral phase transition in NJL model.Comment: 21 pages, 6 figures, misprints are correcte
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