14,395 research outputs found
Phonons in aluminum at high temperatures studied by inelastic neutron scattering
Inelastic neutron scattering measurements on aluminum metal were performed at temperatures of 10, 150, 300, 525, and 775 K using direct-geometry Fermi chopper spectrometers. The temperature dependent phonon density of states (DOS) was determined from the scattering, and was used to fit Born–von Kármán models of lattice dynamics. The shifts in the phonon frequencies with increasing temperature were largely explained by the softening of the longitudinal force constants out to third nearest neighbors. A significant broadening of the phonon spectra at high temperatures was also measured. The phonon DOS was used to determine the vibrational contributions to the entropy of aluminum as a function of temperature. All other contributions to the entropy of aluminum were calculated or assessed, and the total entropy was in excellent agreement with the NIST-JANAF compilation [M. W. Chase, J. Phys. Chem. Ref. Data Monogr. 9, 59 (1998)]. Anharmonic effects were attributed to phonon-phonon interactions. The quasiharmonic approximation was generally successful, but its weaknesses are discussed
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Unemployment alters the set-point for life satisfaction
According to set-point theories of subjective well-being, people react to events, but then return to
initial levels of happiness and satisfaction over time. We test this idea by examining reaction and
adaptation to unemployment in a 15-year longitudinal study. In accordance with set-point theory,
individuals first reacted strongly to unemployment and then shifted back toward their former (or
“baseline”) levels of life satisfaction. However, on average, individuals did not completely return to
their former levels of life satisfaction, even after they became re-employed. The findings suggests
that even a short period of unemployment can cause an alteration in a person’s long-term set-point.
Within-person analyses showed, however, that there are considerable individual differences in
reaction and adaptation to unemployment. Although there was substantial stability in life
satisfaction over the years, unemployment did influence long-term levels, thus suggesting that in
addition to personality, long-term subjective well-being can also be influenced by life
circumstances
Electron-phonon interactions and high-temperature thermodynamics of vanadium and its alloys
Inelastic neutron scattering was used to measure the phonon densities of states (DOSs) for pure V and solid solutions of V with 6 to 7at% of Co, Nb, and Pt, at temperatures from 10 K to 1323 K. Ancillary measurements of heat capacity and thermal expansion are reported on V and V-7at%Co and used to help identify the different sources of entropy. Pure V exhibits an anomalous anharmonic stiffening of phonons with increasing temperature. This anharmonicity is suppressed by Co and Pt, but not by isoelectronic Nb solutes. The changes in phonon frequency with alloying and with temperature both correlate to the decrease in electron density of states (DOS) at the Fermi level as calculated using density functional theory. The effects of both temperature and alloying can be understood in terms of an adiabatic electron-phonon interaction (EPI), which broadens sharp features in the electron DOS. These results show that the adiabatic EPI can influence the phonon thermodynamics at temperatures exceeding 1000 K, and that thermal trends of phonons may help assess the strength of the EPI
The Rise of Gay Culture and Why Portland is Different
This paper serves as a short history of the gay movement in Portland, as well as the reasons why Portland’s movement was inherently dissimilar to the movements of other major cities. It begins by providing historical context on the movements of some of Americas biggest cities, focusing primarily on the 1969 events of the Stonewall Riots in New York, the election and assassination of Harvey Milk in San Francisco, and Seattle’s movement for the purpose of comparison. A brief history on homosexuality in Portland’s recent past follows, going on then to the influence of “Darcelle’s” for the growing gay movement in the late 1970s and 1980s. The election of Portland’s first gay mayor, Sam Adams, in 2008 concludes the paper
The Rise of Gay Culture and Why Portland is Different
This paper serves as a short history of the gay movement in Portland, as well as the reasons why Portland’s movement was inherently dissimilar to the movements of other major cities. It begins by providing historical context on the movements of some of Americas biggest cities, focusing primarily on the 1969 events of the Stonewall Riots in New York, the election and assassination of Harvey Milk in San Francisco, and Seattle’s movement for the purpose of comparison. A brief history on homosexuality in Portland’s recent past follows, going on then to the influence of “Darcelle’s” for the growing gay movement in the late 1970s and 1980s. The election of Portland’s first gay mayor, Sam Adams, in 2008 concludes the paper
TARGET2 et l’intégration financière européenne.
Cet article analyse les conséquences de la mise en oeuvre de TARGET2, qui a démarré le 19 novembre 2007, sur la gestion de la liquidité, l’organisation des établissements et l’intégration financière européenne.Intégration financière, liquidité, liquidité intrajournalière, système de paiement, TARGET, TARGET2.
High-Resolution Near-Infrared Imaging and Polarimetry of Four Proto-Planetary Nebulae
High-resolution near-infrared HST NICMOS (F160W, F222M) images and
polarization (2 um) observations were made of four bipolar proto-planetary
nebulae (PPNs): IRAS 17150-3224, IRAS 17441-2411, IRAS 17245-3951, and IRAS
16594-4656. The first three of these are viewed nearly edge-on, and for the
first time the central stars in them are seen. Color maps reveal a reddened
torus between the bipolar lobes in the edge-on cases, with bluer lobes. The
polarization values are high, with maximum values ranging from 40 to 80%. The
polarization patterns are basically centrosymmetric, with some deviations in
the low polarization equatorial regions. For IRAS 17150-3224, circumstellar
arcs are seen at 1.6 um, along with a newly-discovered loop in the equatorial
region. Bright caps are seen at the end of the lobes, indicating that they are
not open-ended. A distinct point-symmetric pattern is seen in the strengths of
the polarization vectors, especially in IRAS 17150-3224. HST NICMOS
observations provide a valuable complement to the WFPC2 visible images in
deriving the basic structure of bipolar PPNs.Comment: 20 pages, 12 figures, accepted for publication in Astronomical
Journal higher resolution figures are available on
http://katherine.as.arizona.edu/~ksu/cv/su_nicmos7840.ps.g
A holistic approach to the evaluation of sustainable housing
Residential housing is often evaluated against single or at best a limited number of similar criteria. These include quantifiable indicators such as energy use and its associated greenhouse gas emissions. It might also include material consumption from an embodied energy or resource use perspective. Social factors or qualitative indicators may be evaluated but are rarely placed or juxtaposed alongside these quantifiable indicators. A one-dimensional approach will be limiting because sustainable development includes both environmental and social factors. This paper describes the methodologies that have been developed to assess housing developments against five quite different criteria. These are: energy use, resource use, neighbourhood character, neighbourhood connectedness and diversity. In each case, high and low sustainability practice has been identified so that ranking is possible. These methodologies have then been tested by evaluating a typical precinct (approximately 400 m by 400 m) of a 1970-80s housing development in a suburb of Geelong. The rankings of the particular precinct have then been combined in a visual way to assist in the evaluation of the housing in a more holistic way. The results of this evaluation method are presented, along with a discussion of the strengths and weaknesses of the methodologies. The research is the outcome of collaboration by a cross-disciplinary group of academics within Deakin’s School of Architecture and Building
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