24,887 research outputs found
Molecular Hydrogen in the Lagoon: H2 line emission from Messier 8
The 2.12 micron v=1-0 S(1) line of molecular hydrogen has been imaged in the
Hourglass region of M8. The line is emitted from a roughly bipolar region,
centred around the O7 star Herschel 36. The peak H2 1-0 S(1) line intensity is
8.2 x 10E-15 erg s-1 cm-2 arcsec-2. The line centre emission velocity varies
from -25 kms in the SE lobe to +45 kms in the NW lobe. The distribution is
similar to that of the CO J=3-2 line. The H2 line appears to be shock-excited
when a bipolar outflow from Herschel 36 interacts with the ambient molecular
cloud. The total luminosity of all H2 lines is estimated to be ~ 16 Lsun and
the mass of the hot molecular gas ~9 x 10E-4 Msun (without any correction for
extinction).Comment: 11 pages, 4 figures (1 in colour). Submitted to Publications of the
Astronomical Society of Australia, December 200
Verdi’s six-fours and la parola scenica
Verdi’s operas display many non-normative six-four chords. The question for the opera analyst, however, is not only what occurs musically, but why it does. Is there a dramatic function being served by this mix of harmonic-intervallic instability? We discuss four types of non-normative six-fours in Verdi: the arrival, wonder, evasion, and dissolving. But, even as we individuate these types, we note that they are all similar in one regard: they are all linked to a crucial dramatic statement that Verdi termed la parola scenica, a textual-musical signal that makes a dramatic situation suddenly evident
Time-independent probabilistic seismic hazard assessment in Western Indonesia - issues, insights and new applications
Insights into the use of genetic clustering to delineate seismogenic source zones for input into probabilistic seismic hazard analysis
Hypersonic propulsion research
The NASA Langley Research Center has conducted hypersonic propulsion research since the 1960s. A variety of inlet concepts were explored and characterized. The emphasis of the inlet program was the development of the short (light weight), fixed geometry, side-wall-compression inlets that operate efficiently over a wide Mach number range. As hypersonic combustion tunnels were developed, programs to study the parameters controlling fuel mixing and combustion with single and multiple strut models were conducted using direct connect test techniques. These various tests supported the design of subscale engine test hardware that integrated inlet and combustor technology and allowed the study of the effect of heat release on thrust and combustor/inlet interaction. A number of subscale engine tests have demonstrated predicted performance levels at Mach 4 and 7 simulated flight conditions
The Efficiency of the Chinese Stock Markets: Some Unfinished Business on the Road to Economic Transformation
In his William S. Vickrey address to the International Atlantic Economic association in 2005, Franklin Allen examined the question of how China has managed to grow rapidly in the absence of many of the factors usually considered essential to economic expansion in Western economies. China had no tradition of the rule of law, corruption was rampant, and the financial institutions that could facilitate growth were inadequate and/or dysfunctional. In particular, the stock and bond markets in China were undeveloped and the banking system did not serve as an institution that could effectively channel individual savings into those companies with the highest potential investment opportunities.
Hypersonic propulsion research
The development of technology for the modular airframe integrated scramjet has been the focus of hypersonic propulsion research for several years. An part of this research, a variety of inlet concepts have been explored and characterized. The emphasis of the inlet program has been the development of the short (light weight), fixed geometry, side wall compression inlets that operate efficiently over a wide Mach number range. As hypersonic combustion tunnels were developed, programs to study the parameters controlling fuel mixing and combustion with single and multiple strut models were conducted using direct connect test techniques. These various tests supported the design of subscale engine test hardware that integrated inlet and combustor technology and allowed the study of the effect of heat release on thrust and combustor/inlet interaction. A number of subscale engine tests have shown predicted performance levels at Mach 4 and 7 simulated flight conditions. A few of the highlights from this research program are summarized
The long-term effects of the micrometeoroid and orbital debris environments on materials used in space
The long-term effects of the orbital debris and micrometeoroid environments on materials that are current candidates for use on space vehicles are discussed. In addition, the limits of laboratory testing to determine these effects are defined and the need for space-based data is delineated. The impact effects discussed are divided into primary and secondary surfaces. Primary surfaces are those that are subject to erosion, pitting, the degradation and delamination of optical coatings, perforation of atomic oxygen erosion barriers, vapor coating of optics and the production of secondary ejecta particles. Secondary surfaces are those that are affected by the result of the perforation of primary surfaces, for example, vapor deposition on electronic components and other sensitive equipment, and the production of fragments with damage potential to internal pressurized elements. The material properties and applications that are required to prevent or lessen the effects described, are defined
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