Quiet, Clean, Short-Haul Experimental Engine (QCSEE) Over-The-Wing (OTW) engine acoustic design

The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the over-the-wing (OTW) nacelle acoustic treatment design are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the OTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment

Quiet Clean Short-haul Experimental Engine (QCSEE). Core engine noise measurements

Noise measurements were taken on a turbofan engine which uses the same core, with minor modifications, employed on the quiet clean short-haul experimental engine (QCSEE) propulsion systems. Both nearfield and farfield noise measurements were taken in order to determine the core internally generated noise levels. The resulting noise measurements were compared to predicted combustor and turbine noise levels, to verify or improve the predicted QCSEE combustor and turbine noise levels

TF34 Quiet Nacelle nearfield acoustic test results

The results of the nearfield acoustic tests conducted on the TF34 Quiet Nacelle are presented. The high fan noise suppression levels being sought (26 PNdB reduction in aft noise) necessitated the use of an extensive system of special nearfield acoustic instrumentation to properly evaluate the suppression achieved. The design, operation, and test results from each of these nearfield acoustic instrumentation systems are presented

Quiet, Clean, Short-Haul, Experimental Engine (QCSEE) Under-The-Wing (UTW) engine acoustic design

The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the under-the-wing (UTW) engine boilerplate and composite nacelle acoustic treatment designs are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the UTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment

Theory and astrophysical consequences of a magnetized torus around a rapidly rotating black hole

(Abbrev.) We analyze the topology, lifetime, and emissions of a torus around a black hole formed in hypernovae and black hole-neutron star coalescence. The torus is ab initio uniformly magnetized, represented by two counter oriented current-rings, and develops a state of suspended accretion against a "magnetic wall" around the black hole. Magnetic stability of the torus gives rise to a new fundamental limit EB/Ek<0.1 for the ratio of poloidal magnetic field energy-to-kinetic energy. The lifetime of rapid spin of the black hole is effectively defined by the timescale of dissipation of black hole-spin energy in the horizon, and satisfies T= 40s (MH/7MSun)(R/6MH)^4(0.03MH/MT) for a black hole of mass MH surrounded by a torus of mass MT and radius R. The torus converts a major fraction Egw/Erot=0.1 into gravitational radiation through a finite number of multipole mass-moments, and a smaller fraction into MeV neutrinos and baryon-rich winds. At a source distance of 100Mpc, these emissions over N=2e4 periods give rise to a characteristic strain amplitude \sqrt{N}hchar=6e-21. We argue that torus winds create an open magnetic flux-tube on the black hole, which carries a minor and standard fraction Ej/Erot=1e-3 in baryon-poor outflows to infinity. We identify this baryon poor output of tens of seconds with GRBs with contemporaneous and strongly correlated emissions in gravitational radiation, conceivably at multiple frequencies. Ultimately, this leaves a black hole binary surrounded by a supernova remnant.Comment: To appear in ApJ (44p

Proposed gravitational wave background from black hole-torus systems

Cosmological gamma-ray bursts may be powered by rotating black holes with contemporaneous emission of gravitational radiation from a surrounding torus. We calculate the resulting stochastic background radiation assuming strong cosmological evolution and a uniform black hole mass distribution of M= (4--14)M_odot. The predicted spectral flux density corresponds to a peak spectral closure density of (1--2) times 10^{-7}, and has comparable contributions at 450 Hz times kappa and over 300--450 Hz times kappa from nearby and distant sources, respectively, where kappa refers to an uncertainty factor of order unity in the radius of the torus. For two optimized advanced LIGO-type detectors the proposed gravitational wave background could be detectable within a year of integration.Comment: To appear in Ap

Jizz and the joy of pattern recognition:virtuosity, discipline and the agency of insight in UK naturalists’ arts of seeing

Approaches to visual skilling from anthropology and STS have tended to highlight the forces of discipline and control in understanding how shared visual accounts of the world are created in the face of potential differences brought about by multi-sensorial perception. Drawing upon a range of observational and interview material from an immersion in naturalist training and biological recording activities between 2003 and 2009, I focus upon jizz, a distinct form of gestalt perception much coveted by naturalist communities in the UK. Jizz is described as a tacit and embodied way of seeing that instantaneously reveals the identity of a species, relying upon but simultaneously suspending the arduous and meticulous study of an organism’s diagnostic characteristics. I explore the potential and limitations of jizz to allow for both visual precision and an enchanted and varied form of encounter with nature. In so doing, I explore how the specific characteristics of wild, intangible and irreverent virtuoso performance work closely together with disciplining taxonomic standards. As such, discipline and irreverence work together, are mutually enabling, and allow for an accommodation rather than a segregation of potential difference brought about by perceptual variety

Dopamine D_2-receptor activation elicits akinesia, rigidity, catalepsy, and tremor in mice expressing hypersensitive 4 nicotinic receptors via a cholinergic-dependent mechanism

Recent studies suggest that high-affinity neuronal nicotinic acetylcholine receptors (nAChRs) containing α4 and β2 subunits (α4β2*) functionally interact with G-protein-coupled dopamine (DA) D_2 receptors in basal ganglia. We hypothesized that if a functional interaction between these receptors exists, then mice expressing an M2 point mutation (Leu9'Ala) rendering 4 nAChRs hypersensitive to ACh may exhibit altered sensitivity to a D_2-receptor agonist. When challenged with the D_(2)R agonist, quinpirole (0.5–10 mg/kg), Leu9'Ala mice, but not wild-type (WT) littermates, developed severe, reversible motor impairment characterized by rigidity, catalepsy, akinesia, and tremor. While striatal DA tissue content, baseline release, and quinpirole-induced DA depletion did not differ between Leu9'Ala and WT mice, quinpirole dramatically increased activity of cholinergic striatal interneurons only in mutant animals, as measured by increased c-Fos expression in choline acetyltransferase (ChAT)-positive interneurons. Highlighting the importance of the cholinergic system in this mouse model, inhibiting the effects of ACh by blocking muscarinic receptors, or by selectively activating hypersensitive nAChRs with nicotine, rescued motor symptoms. This novel mouse model mimics the imbalance between striatal DA/ACh function associated with severe motor impairment in disorders such as Parkinson’s disease, and the data suggest that a D_(2)R–α4*-nAChR functional interaction regulates cholinergic interneuron activity.—Zhao-Shea, R., Cohen, B. N., Just, H., McClure-Begley, T., Whiteaker, P., Grady, S. R., Salminen, O., Gardner, P. D., Lester, H. A., Tapper, A. R. Dopamine D2-receptor activation elicits akinesia, rigidity, catalepsy, and tremor in mice expressing hypersensitive α4 nicotinic receptors via a cholinergic-dependent mechanism