Study of blade aspect ratio on a compressor front stage aerodynamic and mechanical design report

A single stage compressor was designed with the intent of demonstrating that, for a tip speed and hub-tip ratio typical of an advanced core compressor front stage, the use of low aspect ratio can permit high levels of blade loading to be achieved at an acceptable level of efficiency. The design pressure ratio is 1.8 at an adiabatic efficiency of 88.5 percent. Both rotor and stator have multiple-circular-arc airfoil sections. Variable IGV and stator vanes permit low speed matching adjustments. The design incorporates an inlet duct representative of an engine transition duct between fan and high pressure compressor

New Insights on Interstellar Gas-Phase Iron

In this paper, we report on the gas-phase abundance of singly-ionized iron (Fe II) for 51 lines of sight, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE). Fe II column densities are derived by measuring the equivalent widths of several ultraviolet absorption lines and subsequently fitting those to a curve of growth. Our derivation of Fe II column densities and abundances creates the largest sample of iron abundances in moderately- to highly-reddened lines of sight explored with FUSE, lines of sight that are on average more reddened than lines of sight in previous Copernicus studies. We present three major results. First, we observe the well-established correlation between iron depletion and and also find trends between iron depletion and other line of sight parameters (e.g. f(H_2), E_(B-V), and A_V), and examine the significance of these trends. Of note, a few of our lines of sight probe larger densities than previously explored and we do not see significantly enhanced depletion effects. Second, we present two detections of an extremely weak Fe II line at 1901.773 A in the archival STIS spectra of two lines of sight (HD 24534 and HD 93222). We compare these detections to the column densities derived through FUSE spectra and comment on the line's f-value and utility for future studies of Fe II. Lastly, we present strong anecdotal evidence that the Fe II f-values derived empirically through FUSE data are more accurate than previous values that have been theoretically calculated, with the probable exception of f_1112.Comment: Accepted for publication in ApJ, 669, 378; see ApJ version for small updates. 53 total pages (preprint format), 7 tables, 11 figure

Rotational CARS application to simultaneous and multiple-point temperature and concentration determination in a turbulent flow

Coherent anti-Stokes Raman scattering (CARS) from the pure rotational Raman lines of N2 is employed to measure the instantaneous (approximately 10 ns) rotational temperature of N2 gas at room temperature and below with good spatial resolution (0.2 x 0.2 x 3.0 cu mm). A broad bandwidth dye laser is used to obtain the entire rotational spectrum from a single laser pulse; the CARS signal is then dispersed by a spectrograph and recorded on an optical multichannel analyzer. A best fit temperature is found in several seconds with the aid of a computer for each experimental spectrum by a least squares comparison with calculated spectra. The model used to calculate the theoretical spectra incorporates the temperature and pressure dependence of the pressure-broadened rotational Raman lines, includes the nonresonant background susceptibility, and assumes that the pump laser has a finite linewidth. Temperatures are fit to experimental spectra recorded over the temperature range of 135 to 296 K, and over the pressure range of .13 to 15.3 atm

Towards a contextual approach to the place–homeless survival nexus: An exploratory case study of Los Angeles County

The characteristics of the immediate locale greatly affect the ability of homeless people to adapt to life on the street and in shelters, with different types of places nurturing different circumstances for survival. Current conceptualizations of the place–survival nexus are too narrow, relying on small-scale, intensive studies of particular places that are known to sustain homeless survival while ignoring more suburban and exurban locales, as well as failing to set these places of survival within the larger socio-economic spaces of the metropolitan area. Further, the literature is heavily qualitative, lacking any kind of ‘‘big picture” quantitative assessment of the nexus. In response, we contribute to the place–survival nexus literature by developing a typology of space for homeless survival and then use interview data to examine the variation in survival strategies across three types of urban space in Los Angeles County. Our results speak to how our innovative and exploratory approach enabled a broader, more extensive and variegated understanding of place–survival among homeless people than previous studie

Health Services in Australia

The establishment of the Federal Health Service stemmed from the need to exclude dangerous infectious diseases from Australia. Disease such as smallpox and plague were constant threats to a country newly settled by Europeans with maritime ties, and cholera was endemic in neighboring countries. There were also the less immediate but acknowledged risks of the introduction into Australia of yellow fever and louse typhus. In other words, the earliest Federal Health Service was essentially a quarantine service -established on the basis of meticulous maritime quarantine and supported by a specially trained staff of quarantine medical officers with a chain of quarantine stations strung around the Australian coastline

Nonelastic nuclear reactions and accompanying gamma radiation

Several aspects of nonelastic nuclear reactions which proceed through the formation of a compound nucleus are dealt with. The full statistical model and the partial statistical model are described and computer programs based on these models are presented along with operating instructions and input and output for sample problems. A theoretical development of the expression for the reaction cross section for the hybrid case which involves a combination of the continuum aspects of the full statistical model with the discrete level aspects of the partial statistical model is presented. Cross sections for level excitation and gamma production by neutron inelastic scattering from the nuclei Al-27, Fe-56, Si-28, and Pb-208 are calculated and compared with avaliable experimental data

The Abundance of Interstellar Fluorine and Its Implications

We report results from a survey of neutral fluorine (F I) in the interstellar medium. Data from the Far Ultraviolet Spectroscopic Explorer (FUSE) were used to analyze 26 lines of sight lying both in the galactic disk and halo, including lines to Wolf-Rayet stars and through known supernova remnants. The equivalent widths of fluorine resonance lines at 951.871 A and 954.827 A were measured or assigned upper limits and combined with a nitrogen curve of growth to obtain F I column densities. These column densities were then used to calculate fluorine depletions. Comparisons are made to the previous study of F I by Federman et al. (2005) and implications for F I formation and depletion are discussed.Comment: 32 pages, 10 figures, Accepted to Ap