Two-stage, low noise advanced technology fan. 4: Aerodynamic final report

A two-stage research fan was tested to provide technology for designing a turbofan engine for an advanced, long range commercial transport having a cruise Mach number of 0.85 -0.9 and a noise level 20 EPNdB below current requirements. The fan design tip speed was 365.8m/sec (1200ft/sec);the hub/tip ratio was 0.4; the design pressure ratio was 1.9; and the design specific flow was 209.2 kg/sec/sq m(42.85lbm/sec/sq ft). Two fan-versions were tested: a baseline configuration, and an acoustically treated configuration with a sonic inlet device. The baseline version was tested with uniform inlet flow and with tip-radial and hub-radial inlet flow distortions. The baseline fan with uniform inlet flow attained an efficiency of 86.4% at design speed, but the stall margin was low. Tip-radial distortion increased stall margin 4 percentage points at design speed and reduced peak efficiency one percentage point. Hub-radial distortion decreased stall margin 4 percentage points at all speeds and reduced peak efficiency at design speed 8 percentage points. At design speed, the sonic inlet in the cruise position reduced stall margin one percentage point and efficiency 1.5 to 4.5 percentage points. The sonic inlet in the approach position reduced stall margin 2 percentage points

Girls in The Boat: Sex Differences in Rowing Performance and Participation

Men outperform women in many athletic endeavors due to physiological and anatomical differences (e.g. larger and faster muscle); however, the observed sex differences in elite athletic performance are typically larger than expected, and may reflect sex-related differences in opportunity or incentives. As collegiate rowing in the United States has been largely incentivized for women over the last 20 years, but not men, the purpose of this study was to examine sex differences in elite rowing performance over that timeframe. Finishing times from grand finale races for collegiate championship on-water performances (n = 480) and junior indoor performances (n = 1,280) were compared between men and women across 20 years (1997–2016), weight classes (heavy vs. lightweight) and finishing place. Participation of the numbers of men and women rowers were also quantified across years. Men were faster than women across all finishing places, weight classes and years of competition and performance declined across finishing place for both men and women (P\u3c0.001). Interestingly, the reduction in performance time across finishing place was greater (P\u3c0.001) for collegiate men compared to women in the heavyweight division. This result is opposite to other sports (e.g. running and swimming), and to lightweight rowing in this study, which provides women fewer incentives than in heavyweight rowing. Correspondingly, participation in collegiate rowing has increased by ~113 women per year (P\u3c0.001), with no change (P = 0.899) for collegiate men. These results indicate that increased participation and incentives within collegiate rowing for women vs. men contribute to sex differences in athletic performance

Experimental evaluation of transonic stators, data and performance report, multiple- circular-arc stator A

Transonic stator with multiple circular arc airfoils and minimum curvature tested over range of flow angles and velocities - stator

An investigation of Fe XV emission lines in solar flare spectra

Previously, large discrepancies have been found between theory and observation for Fe XV emission line ratios in solar flare spectra covering the 224-327 A wavelength range, obtained by the Naval Research Laboratory's S082A instrument on board Skylab. These discrepancies have been attributed to either errors in the adopted atomic data or the presence of additional atomic processes not included in the modelling, such as fluorescence. However our analysis of these plus other S082A flare observations (the latter containing Fe XV transitions between 321-482 A), performed using the most recent Fe XV atomic physics calculations in conjunction with a CHIANTI synthetic flare spectrum, indicate that blending of the lines is primarily responsible for the discrepancies. As a result, most Fe XV lines cannot be employed as electron density diagnostics for solar flares, at least at the spectral resolution of S082A and similar instruments (i.e. ~ 0.1 A). An exception is the intensity ratio I(321.8 A)/I(327.0 A), which appears to provide good estimates of the electron density at this spectral resolution.Comment: 6 pages, 3 figures, Astronomy & Astrophysics, in pres

Observations on the water distribution and extractable sugar content in carrot slices after pulsed electric field treatment

peer-reviewedThe impact of pulsed electric field (PEF) processing conditions on the distribution of water in carrot tissue and extractability of soluble sugars from carrot slices was studied. Time domain NMR relaxometry was used to investigate the water proton mobility in PEF-treated carrot samples. Three distinct transverse relaxation peaks were observed in untreated carrots. After PEF treatment only two slightly-overlapping peaks were found; these were attributed to water present in the cytoplasm and vacuole of carrot xylem and phloem tissues. This post-treatment observation indicated an increase in water permeability of tissues and/or a loss of integrity in the tonoplast. In general, the stronger the electric field applied, the lower the area representing transverse relaxation (T2) values irrespective of treatment duration. Moreover an increase in sucrose, β- and α-glucose and fructose concentrations of carrot slice extracts after PEF treatment suggested increases in both cell wall and vacuole permeability as a result of exposure to pulsed electric fields.The authors acknowledge financial support from the Irish Phytochemical Food Network (IPFN) project funded under the Food Institutional Research Measure (FIRM, 06/TNI/AFRC6) of the Irish Department of Agriculture, Food and Marine. Dr. Aguiló-Aguayo thanks Generalitat of Catalonia for the postdoctoral grant Beatriu de Pinós (BP-DGR2010). E. Balagueró thanks the Lifelong Learning Programme for the internship grant Leonardo da Vinci MOTIVA3 (201 1-1-ES1-LEO02-34225)

How should we ‘care’ for LGBT+ students within higher education?

This article draws on a recent U.K. research project about lesbian, gay, bisexual and trans (LGBT+) perspectives on university to examine the implications for pastoral care and other service provision on campus. In a departure from previous scholarship that has tended to understand LGBT+ students as ‘vulnerable’ and/or needing ‘support’, it argues that university spaces should be (re)framed in a way that moves beyond (only) personal or individual ‘care’. The article outlines some of the issues that LGBT+ students may face under the following headings: Curriculum and course content; Discrimination, prejudice and bullying; Facilities and service provision on campus; A continuum of experiences. Following these, a final section draws some conclusions and implications for practice in higher education

Supernova 1996cr: SN 1987A's Wild Cousin?

We report on new VLT optical spectroscopic and multi-wavelength archival observations of SN1996cr, a previously identified ULX known as Circinus Galaxy X-2. Our optical spectrum confirms SN1996cr as a bona fide type IIn SN, while archival imaging isolates its explosion date to between 1995-02-28 and 1996-03-16. SN1996cr is one of the closest SNe (~3.8 Mpc) in the last several decades and in terms of flux ranks among the brightest radio and X-ray SNe ever detected. The wealth of optical, X-ray, and radio observations that exist for this source provide relatively detailed constraints on its post-explosion expansion and progenitor history, including an preliminary angular size constaint from VLBI. The archival X-ray and radio data imply that the progenitor of SN1996cr evacuated a large cavity just prior to exploding: the blast wave likely expanded for ~1-2 yrs before eventually striking the dense circumstellar material which surrounds SN1996cr. The X-ray and radio emission, which trace the progenitor mass-loss rate, have respectively risen by a factor of ~2 and remained roughly constant over the past 7 yr. This behavior is reminiscent of the late rise of SN1987A, but 1000 times more luminous and much more rapid to onset. Complex Oxygen line emission in the optical spectrum further hints at a possible concentric shell or ring-like structure. The discovery of SN1996cr suggests that a substantial fraction of the closest SNe observed in the last several decades have occurred in wind-blown bubbles. An Interplanetary Network position allows us to reject a tentative GRB association with BATSE 4B960202. [Abridged]Comment: 25 pages with tables, 12 figures (color), accepted to ApJ, comments welcome; v2 - updated to reflect the subsequent rejection of our tentative GRB association based on a revised error region from the Interplanetary Network (thanks to Kevin Hurley) and include a few additional references; v3 - corrected some errors in Tables 7 and

Electron-Ion Recombination on Grains and Polycyclic Aromatic Hydrocarbons

With the high-resolution spectroscopy now available in the optical and satellite UV, it is possible to determine the neutral/ionized column density ratios for several different elements in a single cloud. Assuming ionization equilibrium for each element, one can make several independent determinations of the electron density. For the clouds for which such an analysis has been carried out, these different estimates disagree by large factors, suggesting that some process (or processes) besides photoionization and radiative recombination might play an important role in the ionization balance. One candidate process is collisions of ions with dust grains. Making use of recent work quantifying the abundances of polycyclic aromatic hydrocarbon molecules and other grains in the interstellar medium, as well as recent models for grain charging, we estimate the grain-assisted ion recombination rates for several astrophysically important elements. We find that these rates are comparable to the rates for radiative recombination for conditions typical of the cold neutral medium. Including grain-assisted ion recombination in the ionization equilibrium analysis leads to increased consistency in the various electron density estimates for the gas along the line of sight to 23 Orionis. However, not all of the discrepancies can be eliminated in this way; we speculate on some other processes that might play a role. We also note that grain-assisted recombination of H+ and He+ leads to significantly lower electron fractions than usually assumed for the cold neutral medium.Comment: LaTeX(12 pages, 8 figures, uses emulateapj5.sty, apjfonts.sty); submitted to ApJ; corrected typo

Oxygen Gas Phase Abundance Revisited

We present new measurements of the interstellar gas-phase oxygen abundance along the sight lines towards 19 early-type galactic stars at an average distance of 2.6 kpc. We derive O {\small I} column densities from {\it HST}/STIS observations of the weak 1355 \AA intersystem transition. We derive total hydrogen column densities [N(H {\small I})+2N(H$_2$)] using {\it HST}/STIS observations of \lya and {\it FUSE} observations of molecular hydrogen. The molecular hydrogen content of these sight lines ranges from f(H$_2$) = 2N(H$_2$)/[N(H {\small I})+2N(H$_2$)] = 0.03 to 0.47. The average $$ of 6.3$\times10^{21}$ cm$^{-2}$ mag$^{-1}$ with a standard deviation of 15% is consistent with previous surveys. The mean oxygen abundance along these sight lines, which probe a wide range of galactic environments in the distant ISM, is 10$^6$ \oh = $408 \pm 13$ (1 $\sigma$ in the mean). %$({\rm O/H})_{gas} = 408 \pm 14$(1 $\sigma$). We see no evidence for decreasing gas-phase oxygen abundance with increasing molecular hydrogen fraction and the relative constancy of \oh suggests that the component of dust containing the oxygen is not readily destroyed. We estimate that, if 60% of the dust grains are resilient against destruction by shocks, the distant interstellar total oxygen abundance can be reconciliated with the solar value derived from the most recent measurements %by Holweger and by Allende Prieto, Lambert & Asplund: of 10$^6$ \oh$_\odot$ = 517 $\pm$ 58 (1 $\sigma$). We note that the smaller oxygen abundances derived for the interstellar gas within 500 pc %by Meyer, Cardelli & Jura or from nearby B star surveys are consistent with a local elemental deficit.Comment: 9 figures, 37 page