52,031 research outputs found
Concentrations of trace elements and compounds in the airborne suspended particulate matter in Cleveland, Ohio, from August 1971 to August 1972 and their dependence on wind direction: Complete data listing and concentration roses
Concentrations of 75 chemical constituents in the airborne particulate matter were measured in Cleveland, Ohio during 1971 and 1972. Daily values, maxima, geometric means and their standard deviations covering a 1-year period (45 to 50 sampling days) at each of 16 sites are presented on microfiche for 60 elements, and for a lesser number of days for 10 polycyclic aromatic hydrocarbon compounds (PAH), the aliphatic hydrocarbon compounds (AH) as a group and carbon. In addition, concentration roses showing directional properties are presented for 39 elements, 10 PAH and the AH as a group. The elements (except carbon) are shown both in terms of concentration and percentage of the suspended particulate matter
Cygnus X-2, super-Eddington mass transfer, and pulsar binaries
We consider the unusual evolutionary state of the secondary star in Cygnus
X-2. Spectroscopic data give a low mass (M_2 \simeq 0.5 - 0.7\msun) and yet a
large radius (R_2 \simeq 7\rsun) and high luminosity (L_2 \simeq 150\lsun).
We show that this star closely resembles a remnant of early massive Case B
evolution, during which the neutron star ejected most of the \sim 3\msun
transferred from the donor (initial mass M_{\rm 2i}\sim 3.6\msun) on its
thermal time-scale yr. As the system is far too wide to result from
common-envelope evolution, this strongly supports the idea that a neutron star
efficiently ejects the excess inflow during super--Eddington mass transfer.
Cygnus X-2 is unusual in having had an initial mass ratio in a narrow critical range near . Smaller lead to long-period systems with the former donor near the Hayashi line,
and larger to pulsar binaries with shorter periods and relatively
massive white dwarf companions. The latter naturally explain the surprisingly
large companion masses in several millisecond pulsar binaries. Systems like
Cygnus X-2 may thus be an important channel for forming pulsar binaries.Comment: 9 pages, 4 encapsulated figures, LaTeX, revised version with a few
typos corrected and an appendix added, accepted by MNRA
An experimental study of fluidization processes under lunar conditions
Fluidized ash flow in simulated lunar soil
Master/slave manipulator system
System capabilities are equivalent to mobility, dexterity, and strength of human arm. Arrangement of torque motor, harmonic drive, and potentiometer combination allows all power and control leads to pass through center of slave with position-transducer arrangement of master, and "stovepipe joint" is incorporated for manipulator applications
Anthropomorphic master/slave manipulator system
An anthropomorphic master/slave manipulator system including master arm apparatus with a plurality of master tubular articulated portions is outlined. Objectives of this investion were to provide a system that accurately and smoothly simulates human limb movement at a remote location. The system has a high frequency response, a high structural stiffness and a design that protects the components of the slave mechanism. Simulation of human movements is possible in outer space, underwater, and in a hazardous environment such as in a high radiation area. The equivalent ability, dexterity, and strength of a human arm are simulated
Fe I and Fe II Abundances of Solar-Type Dwarfs in the Pleiades Open Cluster
We have derived Fe abundances of 16 solar-type Pleiades dwarfs by means of an
equivalent width analysis of Fe I and Fe II lines in high-resolution spectra
obtained with the Hobby - Eberly Telescope and High Resolution Spectrograph.
Abundances derived from Fe II lines are larger than those derived from Fe I
lines (herein referred to as over-ionization) for stars with Teff < 5400 K, and
the discrepancy (deltaFe = [Fe II/H] - [Fe I/H]) increases dramatically with
decreasing Teff, reaching over 0.8 dex for the coolest stars of our sample. The
Pleiades joins the open clusters M 34, the Hyades, IC 2602, and IC 2391, and
the Ursa Major moving group, demonstrating ostensible over-ionization trends.
The Pleiades deltaFe abundances are correlated with Ca II infrared triplet and
Halpha chromospheric emission indicators and relative differences therein.
Oxygen abundances of our Pleiades sample derived from the high-excitation O I
triplet have been previously shown to increase with decreasing Teff, and a
comparison with the deltaFe abundances suggests that the over-excitation
(larger abundances derived from high excitation lines relative to low
excitation lines) and over-ionization effects that have been observed in cool
open cluster and disk field main sequence (MS) dwarfs share a common origin.
Star-to-star Fe I abundances have low internal scatter, but the abundances of
stars with Teff < 5400 K are systematically higher compared to the warmer
stars. The cool star [Fe I/H] abundances cannot be connected directly to
over-excitation effects, but similarities with the deltaFe and O I triplet
trends suggest the abundances are dubious. Using the [Fe I/H] abundances of
five stars with Teff > 5400 K, we derive a mean Pleiades cluster metallicity of
[Fe/H] = +0.01 +/- 0.02.Comment: 32 pages, 7 figures, 7 tables; accepted by PAS
Solar radio burst and in situ determination of interplanetary electron density
A few interplanetary electron density scales which were derived from the analysis of interplanetary solar radio burst are discussed and compared to a model derived from 1974 to 1980 Helios 1 and 2 in situ density observations made in the 0.3 to 1.0 AU range. The Helios densities were normalized to 1976 with the aid of IMP and ISEE data at 1 AU, and were then sorted into 0.1 AU bins and logarithmically averaged within each bin. The best fit to these 1976-normalized, bin averages is N(R(AU)) = 6.1 R(-2.10)/cu cm. This model is in rather good agreement with the solar burst determination if the radiation is assumed to be on the second harmonic of the plasma frequency. This analysis also suggests that the radio emissions tend to be produced in regions denser than the average where the density gradient decreases faster with distance than the observed R(-2.10)
Cepstral analysis based on the Glimpse proportion measure for improving the intelligibility of HMM-based synthetic speech in noise
In this paper we introduce a new cepstral coefficient extraction method based on an intelligibility measure for speech in noise, the Glimpse Proportion measure. This new method aims to increase the intelligibility of speech in noise by modifying the clean speech, and has applications in scenarios such as public announcement and car navigation systems. We first explain how the Glimpse Proportion measure operates and further show how we approximated it to integrate it into an existing spectral envelope parameter extraction method commonly used in the HMM-based speech synthesis framework. We then demonstrate how this new method changes the modelled spectrum according to the characteristics of the noise and show results for a listening test with vocoded and HMM-based synthetic speech. The test indicates that the proposed method can significantly improve intelligibility of synthetic speech in speech shaped noise. Index Terms — cepstral coefficient extraction, objective measure for speech intelligibility, Lombard speech, HMM-based speech synthesis 1
Ion engine thrust vector study, phase 2 Quarterly report
Performance prediction for expected thrust misalignment in electron bombardment ion thruste
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