77 FR 14061 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Northern Spotted Owl

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-08

... conservation. Experimental management of the barred owl threat is being addressed through a separate decision... move forward with a study on the experimental removal of barred owls. We will release the EIS for... experimental removal study, that decision will not include a determination on whether or how barred owls would...

VIEW OF SHEAR (ELECTRIC POWERED), SCALE HOUSE TO LEFT. BARS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF SHEAR (ELECTRIC POWERED), SCALE HOUSE TO LEFT. BARS ARE PLACED ON WEIGHING SCALE SHOWN LOWER LEFT. 15-TON CLEVELAND CRANE HANDLES BARS FOR FINAL LOADING INTO RAILROAD CARS (12" BAY) AND FOR MOVING FROM TABLE TO SHEAR TABLE. - Cambria Iron Company, Gautier Works, 12" Mill, Clinton Street & Little Conemaugh River, Johnstown, Cambria County, PA

A piezo-bar pressure probe

NASA Technical Reports Server (NTRS)

Friend, W. H.; Murphy, C. L.; Shanfield, I.

1967-01-01

Piezo-bar pressure type probe measures the impact velocity or pressure of a moving debris cloud. It measures pressures up to 200,000 psi and peak pressures may be recorded with a total pulse duration between 5 and 65 musec.

Characterizing bars in low surface brightness disc galaxies

NASA Astrophysics Data System (ADS)

Peters, Wesley; Kuzio de Naray, Rachel

2018-05-01

In this paper, we use B-band, I-band, and 3.6 μm azimuthal light profiles of four low surface brightness galaxies (LSBs; UGC 628, F568-1, F568-3, F563-V2) to characterize three bar parameters: length, strength, and corotation radius. We employ three techniques to measure the radius of the bars, including a new method using the azimuthal light profiles. We find comparable bar radii between the I-band and 3.6 μm for all four galaxies when using our azimuthal light profile method, and that our bar lengths are comparable to those in high surface brightness galaxies (HSBs). In addition, we find the bar strengths for our galaxies to be smaller than those for HSBs. Finally, we use Fourier transforms of the B-band, I-band, and 3.6 μm images to characterize the bars as either `fast' or `slow' by measuring the corotation radius via phase profiles. When using the B- and I-band phase crossings, we find three of our galaxies have faster than expected relative bar pattern speeds for galaxies expected to be embedded in centrally dense cold dark matter haloes. When using the B-band and 3.6 μm phase crossings, we find more ambiguous results, although the relative bar pattern speeds are still faster than expected. Since we find a very slow bar in F563-V2, we are confident that we are able to differentiate between fast and slow bars. Finally, we find no relation between bar strength and relative bar pattern speed when comparing our LSBs to HSBs.

Kinematic imprints from the bar and spiral structures in the galatic disk

NASA Astrophysics Data System (ADS)

Figueras, F.; Antoja, T.; Valenzuela, O.; Romero-Gómez, M.; Pichardo, B.; Moreno, E.

2011-12-01

At 140 years of the discovery of the moving groups, these stellar streams are emerging as powerful tools to constrain the models for the spiral arms and the Galactic bar in the Gaia era. From the kinematic-age-metallicity analysis in the solar neighbourhood it is now well established that some of these kinematic structures have a dynamical origin, different from the classical cluster disruption hypothesis. Test particle simulations allow us to definitively establish that these local structures can be created by the dynamical resonances of material spiral arms and not exclusively by the Galactic bar. First studies to evaluate the capabilities of the future Gaia data to detect and characterize moving groups at 2-6 kpc from the solar neighborhood are discussed.

A pilot study examining density of suppression measurement in strabismus.

PubMed

Piano, Marianne; Newsham, David

2015-01-01

Establish whether the Sbisa bar, Bagolini filter (BF) bar, and neutral density filter (NDF) bar, used to measure density of suppression, are equivalent and possess test-retest reliability. Determine whether density of suppression is altered when measurement equipment/testing conditions are changed. Our pilot study had 10 subjects aged ≥18 years with childhood-onset strabismus, no ocular pathologies, and no binocular vision when manifest. Density of suppression upon repeated testing, with clinic lights on/off, and using a full/reduced intensity light source, was investigated. Results were analysed for test-retest reliability, equivalence, and changes with alteration of testing conditions. Test-retest reliability issues were present for the BF bar (median 6 filter change from first to final test, p = 0.021) and NDF bar (median 5 filter change from first to final test, p = 0.002). Density of suppression was unaffected by environmental illumination or fixation light intensity variations. Density of suppression measurements were higher when measured with the NDF bar (e.g. NDF bar = 1.5, medium suppression, vs BF bar = 6.5, light suppression). Test-retest reliability issues may be present for the two filter bars currently still under manufacture. Changes in testing conditions do not significantly affect test results, provided the same filter bar is used consistently for testing. Further studies in children with strabismus having active amblyopia treatment would be of benefit. Despite extensive use of these tests in the UK, this is to our knowledge the first study evaluating filter bar equivalence/reliability.

Observations from behind the bar: changing patrons' behaviours in response to smoke-free legislation in Scotland.

PubMed

Hilton, Shona; Cameron, Jane; MacLean, Alice; Petticrew, Mark

2008-07-14

"Smoke-Free" legislation prohibiting smoking in all enclosed public places was introduced in March 2006. This qualitative study presents insights from bar workers about their observations of the changing social bar environment, changing patrons' behaviours and challenges bar workers have faced in managing smoke-free legislation. Twelve in-depth interviews were conducted between November 2006 and January 2007 with a purposively-selected sample of bar workers, identified from a larger quantitative study evaluating the impact of the legislation in Scotland [the Bar Workers' Health and Environmental Tobacco Smoke Exposure project (BHETSE)]. Bar workers all spoke of the improvements the legislation had brought to their working lives and the greater comfort it appeared to offer patrons. Bar workers reported that patrons were generally quick to accept and comply with the new law, and that families had become a greater feature of pub life since the legislation. However, they expressed concerns that older men seemed to have had most difficulty adjusting to the legislation and lack of knowledge about the best practices they should adopt in order to reduce the risks of unattended drinks being spiked and of anti-social behaviour associated with patrons moving outside to smoke. Smoke-free legislation is changing the social context of smoking in Scotland. Further research to assess the impact the legislation is having on older male smokers and on the incidence of drink spiking would be useful. More specifically, bar workers would benefit from guidance on how to manage issues arising from patrons moving outside to smoke.

Dancing around the Black Hole

NASA Astrophysics Data System (ADS)

2001-08-01

ISAAC Finds "Cool" Young Stellar Systems at the Centres of Active Galaxies Summary Supermassive Black Holes are present at the centres of many galaxies, some weighing hundreds of millions times more than the Sun. These extremely dense objects cannot be observed directly, but violently moving gas clouds and stars in their strong gravitational fields are responsible for the emission of energetic radiation from such "active galaxy nuclei" (AGN) . A heavy Black Hole feeds agressively on its surroundings . When the neighbouring gas and stars finally spiral into the Black Hole, a substantial fraction of the infalling mass is transformed into pure energy. However, it is not yet well understood how, long before this dramatic event takes place, all that material is moved from the outer regions of the galaxy towards the central region. So how is the food for the central Black Hole delivered to the table in the first place? To cast more light on this central question, a team of French and Swiss astronomers [1] has carried out a series of trailblazing observations with the VLT Infrared Spectrometer And Array Camera (ISAAC) on the VLT 8.2-m ANTU telescope at the ESO Paranal Observatory. The ISAAC instrument is particularly well suited to this type of observations. Visible light cannot penetrate the thick clouds of dust and gas in the innermost regions of active galaxies, but by recording the infrared light from the stars close to the Black Hole , their motions can be studied. By charting those motions in the central regions of three active galaxies (NGC 1097, NGC 1808 and NGC 5728), the astronomers were able to confirm the presence of "nuclear bars" in all three. These are dynamical structures that "open a road" for the flow of material towards the innermost region. Moreover, the team was surprised to discover signs of a young stellar population near the centres of these galaxies - stars that have apparently formed quite recently in a central gas disk. Such a system is unstable, however, and will soon disrupt. At some moment, many of those young stars may get too close to the monster in the centre and suffer an unhappy fate... PR Photo 25a/01 : The active galaxy NGC 1097 (R-band image) PR Photo 25b/01 : The active galaxy NGC 1808 (H-band image) PR Photo 25c/01 : The active galaxy NGC 5728 (K-band image) PR Photo 25d/01 : Schematic drawing of the various structural components mentioned in the text. PR Photo 25e/01 : ISAAC spectrum (2.3 µm) of the central region of NGC 1808 PR Photo 25f/01 : Stellar motions at the centre of NGC 1808 Central black holes in galaxies ESO PR Photo 25a/01 ESO PR Photo 25a/01 [Preview - JPEG: 400 x 489 pix - 39k] [Normal - JPEG: 800 x 977 pix - 296k] ESO PR Photo 25b/01 ESO PR Photo 25b/01 [Preview - JPEG: 400 x 499 pix - 40k] [Normal - JPEG: 800 x 997 pix - 168k] ESO PR Photo 25c/01 ESO PR Photo 25c/01 [Preview - JPEG: 400 x 488 pix - 47k] [Normal - JPEG: 800 x 975 pix - 384k] Caption : Photos of three active galaxies that were observed with ISAAC during the present programme. They show NGC 1097 (R-band; Photo 25a/01) and the central areas of NGC 1808 (H-band; Photo 25b/01) and NGC 5728 (K-band; Photo 25c/01). The bar-like structures and the luminous centres where the Black Holes are located are well visible - they are discussed in the text. The distances to these galaxies are approximately 55, 35 and 120 million light-years, respectively; the local scales are indicated in the photos. Technical information about these photos is available below. Recent research with space- and ground-based astronomical telescopes indicate that there are very heavy Black Holes at the centres of most galaxies. There is also general agreement among scientists that many of the closest neighbours of our own Milky Way Galaxy, for example the large spiral Andromeda Galaxy and the peculiar Centaurus A galaxy (cf. ESO PR 04/01 ), do contain central black holes with masses from millions to billions of solar masses [2]. Black Holes have an extremely intense gravitational field and as light can not escape from them, they are dark and invisible. Indeed, with presently available observational tools, they cannot be detected directly, only by effects resulting from interaction with their immediate surroundings. A small fraction of the black holes in galaxies are thus revealed by the spectacular activity they trigger in the central part of their hosts. Attracted by that heavy object, enormous quantities of gas (mostly hydrogen) spiral inwards towards the black hole. A disk-shaped structure forms in which the gas moves ever faster around the black hole while enormous amounts of energy are radiated at all wavelengths [3]. Getting the food to the Black Hole A great debate is now going on among scientists about how exactly the black holes are "fed". How is the gas first transported into the disk to fuel the seemingly insatiable supermassive black hole? It is still not well understood how the gas is moved from the outside to within a distance of 1000 light-years of the centre. Various violent processes have been mentioned in this context, like the merger of galaxies. A fine example of such an event was recently observed at the distant quasar HE 1013-2136 with the ESO Very Large Telescope, cf. ESO PR 13/01. The role of "nuclear bars" ESO PR Photo 25d/01 ESO PR Photo 25d/01 [Preview - JPEG: 364 x 400 pix - 89k] [Normal - JPEG: 727 x 800 pix - 264k] Caption : PR Photo 25d/01 is a schematic drawing of the various components of a double-barred galaxy, as mentioned in the text. Another possibility to move the gas inwards is the presence of bar-like structures at the centres of some galaxies, so-called "nuclear bars" . They look like small versions of the well-known, beautiful large-scale bar-like structures seen in galaxies like NGC 1365 (cf. ESO PR Photos 08a-e/99 ), but the responsible dynamical processes may possibly be somewhat different. Photo 25d/01 shows the various components that are discussed here in a schematic way. Acting as a gravitational brush, a bar that is thousands of light-years long efficiently "sweeps" the gas in that galaxy towards its core. When sufficient material has collected there, that matter may become dynamically "decoupled", forming a smaller bar at the centre of the larger "primary" bar. Such a "nuclear bar" may then, at least in theory, take over and let the gas move further inwards towards the central black hole. Until now, nuclear bars have mostly been seen on detailed images as small, elongated structures embedded within the larger primary bars - such structures may ressemble a "Russian doll". In addition, nuclear bars have been detected indirectly due to their gravitational effects, by means of very accurate measurements of the motions of the gas in the central region in a few galaxies. A first observational campaign by a team of French and Swiss astronomers [1] with the ESO Very Large Telescope (VLT) has now brought new, important insights about these nuclear bars. ISAAC spectra of the innermost regions of three active galaxies ESO PR Photo 25e/01 ESO PR Photo 25e/01 [Preview - JPEG: 400 x 424 pix - 40k] [Normal - JPEG: 800 x 847 pix - 256k] ESO PR Photo 25f/01 ESO PR Photo 25f/01 [Preview - JPEG: 400 x 241 pix - 40k] [Normal - JPEG: 800 x 401 pix - 112k] Caption : PR Photo 25e/01 is a reproduction of a long-slit ISAAC spectrum of the central region of the active galaxy NGC 1808 . It is in the 2.3 µm spectral region and the wavelength increases towards right. Several strong, vertical bands are seen; they are caused by CO-molecules in the atmospheres of the stars in this area. The bright band at the centre corresponds to the nucleus of the galaxy within which the central black hole is located. The characteristic S-shape is a result of the rotation of the stars around this centre, due to the Doppler effect. Technical information about this photo is available below. In the left half of PR Photo 25f/01 , the measured velocities (ordinate) of the stars near the centre of NGC 1808 are plotted at different distances from the nucleus (abscissa). The right half shows the corresponding curve after "removal" of the effect from the rotation - the remaining spread is a direct measure of the "velocity dispersion" and the individual stellar motions. As can be clearly seen, the width of the "band" decreases towards the centre, indicating the presence of a "dynamically cool" central stellar system. For more details, see the text. The scientists embarked upon a project with the goal of investigating in detail the motions of stars in the central regions of some active, comparatively "nearby" galaxies. As the innermost regions of such galaxies are usually quite dusty, the observations were carried out in infrared light that penetrates the dust clouds much better than does visible light. Thanks to its high efficiency and excellent imaging quality and spectral resolution, the VLT Infrared Spectrometer And Array Camera (ISAAC) is superbly suited for such work. Several galaxies with active centres were selected for the first observing runs in 1999 and 2000, among these NGC 1097, NGC 1808 and NGC 5728 that are shown in PR Photos 25a-c/01 . Infrared spectra were obtained in the 2.3 µm wavelength region in which a number of molecular spectral bands are seen, cf. PR Photo 25e/01 . They are caused by carbon monoxide ( 12 CO) molecules in the atmospheres of the stars located near the centres of the galaxies. Stellar motions By measuring the exact wavelengths of these molecular bands, it is possible to determine (from the Doppler effect), first, the mean velocity of the stars ( PR Photo 25f/01 ; left) and, secondly, the spread in this velocity (known as the "velocity dispersion" ; right). The first value reflects the general speed with which the stars move around the central black hole. The second indicates the extent to which the individual stellar motions deviate from that mean value. The comparison with the flight of a swarm of bees is useful: the mean velocity tells how fast the swarm moves forward as a whole - this is the ordered motion of the group. The second value instead indicates how much (or how fast) the individual bees move around inside the swarm - this is the spread in random velocities among the bees. Dynamical temperature is another concept defined by velocity dispersion. A warm gas is a gas where the molecules swarm around at high random speeds, while the molecules in a cold gas have low velocity dispersion. Astronomers often borrow this terminology and refer to stellar systems with low velocity dispersions as "dynamically cool systems". Confirming the "nuclear bars"... When "mapped" over the entire central area of a galaxy, these stellar velocity values provide detailed information about the gravitational field, and thus the mass distribution in the innermost region of the galaxy. The ISAAC observations did confirm the presence of "nuclear bars" in NGC 1097, NGC 1808 and NGC 5728. They also showed that these bars are truly "decoupled" stellar systems - their motions are only determined by the mass distribution in that area. ...and discovering a "dynamically cool" stellar system! However, the astronomers were very surprised to discover that in all three galaxies, the velocity dispersion is decreasing towards the centre, exactly contrary to what is predicted by simple models . The likely reason is the presence in the central region of a "newborn" system of stars whose individual velocities have not yet had time to "heat up". The project leader, Eric Emsellem explains: "Slower individual stellar motions correspond to a lower 'dynamical temperature' of the stellar system in this innermost region. We interpret this as evidence for a recent infall of gas that was induced by the nuclear bar. This has created a new gaseous disk at the centre of the galaxy, which has given birth to new stars. They all move around the black hole with more or less the same circular velocity as the gas from which they were born" . Agreement between observations and models This interesting scenario is supported by recent, extensive model computations by the team. In these computer models, large numbers of "stars" (mass points) move in a model galaxy with both a large and a nuclear bar, as observed in the three galaxies. Herve Wozniak refers to them as "self-consistent N-body simulations" and explains why the team is enthusiastic: "When our models also include star formation in the gas in the central region, a new, "dynamically cool" component of young stars emerges and mixes with the old stellar population" . He goes on: "The light from those young stars is superposed on that from the older ones in that area. Because of this, the overall "velocity dispersion" in the central region is then smaller than what it is further out. This is exactly as we observed in the ISAAC spectra obtained in the present programme" . Eric Emsellem points out that such a "dynamically cold" system is unstable and cannot last very long . "Soon it will "heat up" due to complex dynamical processes. It is quite possible that some of these stars will eventually end up as food for the hungry Black Hole.." Prospects With these new high-resolution infrared observations of the structure and the objects in the innermost regions of active galaxies, ISAAC and the VLT are paving the way for future studies of the processes that take place in the immediate neighbourhood of the central black holes. More active galaxies will now be observed with this method and it will be interesting to see if the presently discovered "cool" and young stellar systems represent a common phenomenon or not. More information The first stages of the research project reported in this Press Release are described in a scientific article ("Dynamics of embedded bars and the connection with AGN" by E. Emsellem et al.) that appeared in the European research journal Astronomy & Astrophysics (Vol. 368, p. 52). Two other articles about the new models and the implied properties of the central stellar population of young stars will follow. Notes [1]: The team consists of Eric Emsellem (Principal Investigator, Centre de Recherche Astronomique de Lyon, France), Didier Greusard and Daniel Friedli (Geneva Observatory, Switzerland), Francoise Combes (DEMIRM, Paris, France), Herve Wozniak (Marseille Observatory, France), Emmanuel Pecontal (Centre de Recherche Astronomique de Lyon, France) and Stephane Leon (University of Cologne, Germany). [2]: Black Holes represent an extreme physical phenomenon; if the Earth were to become one, it would measure no more than a few millimetres across. The gravitational field around a black hole is so intense that even light can not escape from it. [3]: On its most energetic and dramatic scale, this scenario results in a quasar , a type of object first discovered in 1963. In this case, the highly energetic centre of a galaxy completely outshines the outer structures and the "quasi-stellar object" appears star-like in smaller telescopes. Technical information about the photos PR Photo 25a/01 with NGC 1097 is a reproduction from the ESO LV archive, extracted via the Hypercat facility. It is based on a 2-hour photographic exposure in the R-band (Kodak IIIa-F emulsion + RG630 filtre) with the ESO 1-m Schmidt Telescope at La Silla and covers a field of about 35 x 35 arcmin 2. On this and the following photos, North is up and East is left. PR Photo 25b/01 of the central region of NGC 1808 was reproduced from an H-band (1.6 µm) image obtained with the IRAC2 camera (now decommissioned) at the MPG/ESO 2.2-m telescope on La Silla. The exposure time was 50 sec and the field measures 2.0 x 2.1 arcmin 2 (original pixel size = 0.52 arcsec). PR Photo 25c/01 of the central region of NGC 5728 was obtained at the 3.5-m Canada-France-Hawaii Telescope (CFHT) and the Adaptive-Optics PUEO instrument; the K-band (2.3 µm) exposure lasted 60 sec and the field measures 38 X 38 arcsec 2. PR Photo 25e/01 shows a raw, long-slit IR-spectrum in the 2.3 µm wavelength region, obtained with ISAAC along the major axis of this galaxy.

Light-front holographic distribution amplitudes of pseudoscalar mesons and their application to B -meson decays

DOE PAGES

Chang, Qin; Brodsky, Stanley J.; Li, Xin-Qiang

2017-05-30

In this article the dynamical spin effects of the light-front holographic wave functions for light pseudoscalar mesons are studied. These improved wave functions are then confronted with a number of hadronic observables: the decay constants of π and K mesons, their ξ -moments, the pion-to-photon transition form factor, and the pure annihilationmore » $$\\bar{B}_s$$ → π + π - and $$\\bar{B}_d$$ → K + K - decays. Taking f π , fK , and their ratio fK / f π as constraints, we perform a χ 2 analysis for the holographic parameters, including the mass scale parameter $$\\sqrtλ$$ and the effective quark masses, and find that the fitted results are quite consistent with the ones obtained from the light-quark hadronic Regge trajectories. In addition, we also show that the end point divergence appearing in the pure annihilation $$\\bar{B}_s$$ → π + π - and $$\\bar{B}_d$$ → K + K - decays can be controlled well by using these improved light-front holographic distribution amplitudes.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

The SLD Collaboration

Average charged multiplicities have been measured separately for {ital b, c} and light quark ({ital u, d, s}) events from Z{sup 0} decays at SLD. Impact parameters of charged tracks were used to select enriched samples of {ital b} and light quark events. We measured the charged multiplicities: {bar {ital n}}{sub {ital uds}} = 19.80 {+-} 0.09 ({ital stat}) {+-} 0.57 ({ital syst}), {bar {ital n}}{sub {ital c}} = 21.17 {+-} 0.44 ({ital stat}) {+-} 1.01 ({ital syst}) and {bar {ital n}}{sub {ital b}}{+-}23.14 {+-} 0.09 ({ital stat}) {+-} 1.03 ({ital syst}) (PRELIMINARY), from which we derived the differences betweenmore » the total average charged multiplicities of {ital c} or {ital b} quark events and light quark events: {delta}{bar {ital n}}{sub {ital c}} = 1.37 {+-} 0.45 ({ital stat}) {+-} 0.86 ({ital syst}) and {delta}{bar {ital n}}{sub {ital b}} = 3.34 {+-} 0. 13 ({ital stat}) {+-} 0.77 ({ital syst}) (PRELIMINARY). We compared these measurements with those at lower center-of-mass energies and with QCD predictions.« less

Enabling Narrow(est) IWA Coronagraphy with STIS BAR5 and BAR10 Occulters

NASA Astrophysics Data System (ADS)

Schneider, Glenn; Gaspar, Andras; Debes, John; Gull, Theodore; Hines, Dean; Apai, Daniel; Rieke, George

2017-09-01

The Space Telescope Imaging Spectrograph's (STIS) BAR5 coronagraphic occulter was designed to provide high-contrast, visible-light, imaging in close (> 0.15") angular proximity to bright point-sources. We explored and verified the functionality and utility of the BAR5 occulter. We also investigated, and herein report on, the use of the BAR10 rounded corners as narrow-angle occulters and compare IWA vs. contrast performance for the BAR5, BAR10, and Wedge occulters. With that, we provide recommendations for the most efficacious BAR5 and BAR10 use on-orbit in support of GO science.

Optical fiber sensor based on a polymer optical fiber macro-bend to study thermal expansion of metals

NASA Astrophysics Data System (ADS)

Pakdeevanich, Paradorn

2018-05-01

Thermal expansion is an important parameter for characterization of metals. As metal is heated, the molecules vibrate more violently and expand in all direction. Investigators have focused to study the thermal strain. However, the amount of expansion is difficult to measure. An attempt has been made to develop an apparatus using optical technique. The principle of this system is the transformation of length changes into changes of light intensity. The purpose of this work is to design and develop an optical fiber sensor based on a macro-bend of a polymer optical fiber. In this system, thermal expansion of metal was converted into the rolling of a needle in which placed beneath a flat bar of metal. Optical fiber sensor was attached to the ended section of a needle. As the crimp tube of the fiber sensor was moved due to thermal expansion of metal, the bend radii of optical fiber sensor was changed. As a sequence, the loss induced by the bending effect was depended on the expansion of metal that changed with temperature. In this study, we utilized optical fiber sensor to monitor and compare the thermal expansion of copper, brass and aluminum. According to our experimental results, the linear response with temperature was reported. The measured values of coefficient of thermal expansion was analyzed to be 0.45, 0.35 and 0.32 a.u./°C for aluminum bar, brass bar and copper bar, respectively. In addition, the effect of the size of the diameter of a needle on the response of bending loss was investigated.

Tunable reflecting terahertz filter based on chirped metamaterial structure

PubMed Central

Yang, Jing; Gong, Cheng; Sun, Lu; Chen, Ping; Lin, Lie; Liu, Weiwei

2016-01-01

Tunable reflecting terahertz bandstop filter based on chirped metamaterial structure is demonstrated by numerical simulation. In the metamaterial, the metal bars are concatenated to silicon bars with different lengths. By varying the conductivity of the silicon bars, the reflectivity, central frequency and bandwidth of the metamaterial could be tuned. Light illumination could be introduced to change the conductivity of the silicon bars. Numerical simulations also show that the chirped metamaterial structure is insensitive to the incident angle and polarization-dependent. The proposed chirped metamaterial structure can be operated as a tunable bandstop filter whose modulation depth, bandwidth, shape factor and center frequency can be controlled by light pumping. PMID:27941833

THEORY AND MEASUREMENT OF VISUAL MECHANISMS

PubMed Central

Crozier, W. J.; Wolf, Ernst

1944-01-01

Flicker contours for a square image of 3° visual angle, centered 6° on the temporal side of the fovea, the light sectored at a focus, are strikingly modified if the same illuminated area is arranged in four squares separated by a narrow opaque cross. The "cone" curves are made much steeper, and their abscissae of inflection (τ' are at higher intensities; Fmax. is not greatly changed, but alters less with change of light-time fraction in the flash cycle (tL). This modification is accompanied by a great enlargement of the scotopic segment of the duplex curves, consistent with the theory of the integrative relations of neural effects in the two groups of units involved. The changes are not consistent with the view that flicker end-points are determined by the activation of retinal cells with a fixed spatial distribution of invariable thresholds. At tL = 0.50 the 3° subdivided area gives very nearly the same contour as does a square 6° x 6°, with the same total perimeter of light-dark separation; the "edge effect" thus suggested is complicated by differences in the dependence of Fmax. and τ' upon tL. When an image pattern is produced by a grid of light bars separated by equally broad opaque spaces (10° x 10° over-all, centered at the fovea), the photopic flicker contours are made very steep and their midpoints are situated at quite low intensities, while the "rod" contribution tends to be more completely fused with the "cone" than is found for fields not subdivided. However, instead of a progressive increase of τ' with tL the curves for tL = 0.75 and 0.90 lie respectively below that for tL = 0.25 and 0.50 for a field of four broader stripes (1.43°) and both are below tL = 0.25 for a field of seven narrower stripes (0.77°). These latter changes are discussed in terms of the participation of subsidiary phenomena involving so called "γ movement." It is pointed out that since in these data σ1/Im is for each set of conditions a statistically constant quantity with a characteristic breadth of scatter σσ, it is possible to calculate a "coefficient of internal correlation" r which is a function of the conditions (as: image area, location, wave length of light, structure of image, light-time fraction) and which describes a property of any entire contour. The changes in r, as a function of the conditions of flicker excitation, reflect changes in the neural organization responsible for the liminal discrimination of flicker. It is shown that as consequence of simple changes in the image field, three parameters, as of the probability summation, are required for the description of a simplex flicker contour—since each of these is independently modifiable as to its magnitude and in its dependence on the light-time fraction. Subdivision of the image, with light sectored at a focus, produces in part only the changes in the flicker contour which we have earlier labelled the "pecten effect." In the latter, with light not sectored at a focus but with bar images moving across a field with inclined fixed opaque bars, the "cone" slope (dF/d log I) is sharply increased for tL > 0.50, but not below tL = 0.50, and the value of τ' is much less than it "should be." Consequently, the change in contrast brought about by the moving contact of light/dark borders is the significant factor in the "pecten effect," not simply pulsatile interruption of the light. PMID:19873392

The economic impact of a smoke-free bylaw on restaurant and bar sales in Ottawa, Canada.

PubMed

Luk, Rita; Ferrence, Roberta; Gmel, Gerhard

2006-05-01

On 1 August 2001, the City of Ottawa (Canada's Capital) implemented a smoke-free bylaw that completely prohibited smoking in work-places and public places, including restaurants and bars, with no exemption for separately ventilated smoking rooms. This paper evaluates the effects of this bylaw on restaurant and bar sales. DATA AND MEASURES: We used retail sales tax data from March 1998 to June 2002 to construct two outcome measures: the ratio of licensed restaurant and bar sales to total retail sales and the ratio of unlicensed restaurant sales to total retail sales. Restaurant and bar sales were subtracted from total retail sales in the denominator of these measures. We employed an interrupted time-series design. Autoregressive integrated moving average (ARIMA) intervention analysis was used to test for three possible impacts that the bylaw might have on the sales of restaurants and bars. We repeated the analysis using regression with autoregressive moving average (ARMA) errors method to triangulate our results. Outcome measures showed declining trends at baseline before the bylaw went into effect. Results from ARIMA intervention and regression analyses did not support the hypotheses that the smoke-free bylaw had an impact that resulted in (1) abrupt permanent, (2) gradual permanent or (3) abrupt temporary changes in restaurant and bar sales. While a large body of research has found no significant adverse impact of smoke-free legislation on restaurant and bar sales in the United States, Australia and elsewhere, our study confirms these results in a northern region with a bilingual population, which has important implications for impending policy in Europe and other areas.

Are some gestalt principles deployed more readily than others during early development? The case of lightness versus form similarity.

PubMed

Quinn, Paul C; Bhatt, Ramesh S

2006-10-01

Four experiments investigated how readily infants achieve perceptual organization by lightness and form similarity. Infants were (a) familiarized with elements that could be organized into rows or columns on the basis of lightness or form similarity and tested with vertical versus horizontal bars depicting the familiar versus novel organization or (b) familiarized with bars and tested with elements. For lightness similarity, generalization occurred in both tasks; however, for form similarity, generalization occurred only in the elements --> bars task. The findings indicate that lightness similarity is more readily deployed than form similarity and are discussed in the context of (a) whether the difference reflects speed of application or experience-based learning, (b) evidence from visual agnosic patients and the time course of application of the principles in healthy adults, and (c) development of dorsal and ventral visual processing streams. Copyright 2006 APA.

A New Species of Tiger Pleco Panaqolus (Siluriformes: Loricariidae) from the Xingu Basin, Brazil

PubMed Central

Melo de Sousa, Leandro

2016-01-01

Panaqolus tankei is described from the Xingu River, Brazil. The new species is diagnosed from P. albomaculatus, P. dentex, P. nix, P. nocturnus, and P. koko by its color pattern consisting of dark and light diagonal bars on the body and bands on the fins (vs. body and fins without bars or bands); from P. albivermis, P. maccus, and P. purusiensis by the width of the dark bars being more or less the same of the light bars (vs. dark bars at least two or three times wider than light bars) and from P. changae by the absence of vermiculation on the head (vs. vermiculation present on head). The new species differs from P. gnomus by the orientation of the bars from posterodorsal to anteroventral direction (vs. anterodorsal to posteroventral direction), and from P. claustellifer by the orientation of the bands in the dorsal fin that are not parallel to the margin (vs. parallel to the margin). The barcoding region (COI) was sequenced for the new species, sequences were deposited in GenBank and were compared with congeners from other drainages. With regard to the current construction of a hydroelectric power plant (a so-called mega dam) in the Xingu River, herewith we increase knowledge of the river Xingu’s ichthyofauna and, thus improve the assessment of the impacts of that construction on the river. PMID:27828981

A New Species of Tiger Pleco Panaqolus (Siluriformes: Loricariidae) from the Xingu Basin, Brazil.

PubMed

Cramer, Christian Andreas; Melo de Sousa, Leandro

2016-01-01

Panaqolus tankei is described from the Xingu River, Brazil. The new species is diagnosed from P. albomaculatus, P. dentex, P. nix, P. nocturnus, and P. koko by its color pattern consisting of dark and light diagonal bars on the body and bands on the fins (vs. body and fins without bars or bands); from P. albivermis, P. maccus, and P. purusiensis by the width of the dark bars being more or less the same of the light bars (vs. dark bars at least two or three times wider than light bars) and from P. changae by the absence of vermiculation on the head (vs. vermiculation present on head). The new species differs from P. gnomus by the orientation of the bars from posterodorsal to anteroventral direction (vs. anterodorsal to posteroventral direction), and from P. claustellifer by the orientation of the bands in the dorsal fin that are not parallel to the margin (vs. parallel to the margin). The barcoding region (COI) was sequenced for the new species, sequences were deposited in GenBank and were compared with congeners from other drainages. With regard to the current construction of a hydroelectric power plant (a so-called mega dam) in the Xingu River, herewith we increase knowledge of the river Xingu's ichthyofauna and, thus improve the assessment of the impacts of that construction on the river.

Comparative study of (0001) and (11\\bar{2}2) InGaN based light emitting diodes

NASA Astrophysics Data System (ADS)

Pristovsek, Markus; Humphreys, Colin J.; Bauer, Sebastian; Knab, Manuel; Thonke, Klaus; Kozlowski, Grzegorz; O'Mahony, Donagh; Maaskant, Pleun; Corbett, Brian

2016-05-01

We have systematically investigated the doping of (11\\bar{2}2) with Si and Mg by metal-organic vapour phase epitaxy for light emitting diodes (LEDs). By Si doping of GaN we reached electron concentrations close to 1020 cm-3, but the topography degrades above mid 1019 cm-3. By Mg doping we reached hole concentrations close to 5 × 1017 cm-3, using Mg partial pressures about 3× higher than those for (0001). Exceeding the maximum Mg partial pressure led to a quick degradation of the sample. Low resistivities as well as high hole concentrations required a growth temperature of 900 °C or higher. At optimised conditions the electrical properties as well as the photoluminescence of (11\\bar{2}2) p-GaN were similar to (0001) p-GaN. The best ohmic p-contacts were achieved by NiAg metallisation. A single quantum well LED emitting at 465 nm was realised on (0001) and (11\\bar{2}2). Droop (sub-linear increase of the light output power) occurred at much higher current densities on (11\\bar{2}2). However, the light output of the (0001) LED was higher than that of (11\\bar{2}2) until deep in the droop regime. Our LEDs as well as those in the literature indicate a reduction in efficiency from (0001) over semi-polar to non-polar orientations. We propose that reduced fields open a loss channel for carriers.

Steering system for a train of rail-less vehicles

DOEpatents

Voight, Edward T.

1983-01-01

A steering system for use with a multiple vehicle train permits tracking without rails of one vehicle after another. This system is particularly useful for moving conveyor systems into and out of curved paths of room and pillar underground mine installations. The steering system features an elongated steering bar pivotally connected to each of adjacent vehicles at end portions of the bar permitting angular orientation of each vehicle in respect to the steering bar and other vehicles. Each end portion of the steering bar is linked to the near pair of vehicle wheels through wheel yoke pivot arms about king pin type pivots. Movement of the steering bar about its pivotal connection provides proportional turning of the wheels to effect steering and tracking of one vehicle following another in both forward and reverse directions.

Enabling Handicapped Nonreaders to Independently Obtain Information: Initial Development of an Inexpensive Bar Code Reader System.

ERIC Educational Resources Information Center

VanBiervliet, Alan

A project to develop and evaluate a bar code reader system as a self-directed information and instructional aid for handicapped nonreaders is described. The bar code technology involves passing a light sensitive pen or laser over a printed code with bars which correspond to coded numbers. A system would consist of a portable device which could…

THE VELOCITY DISTRIBUTION OF NEARBY STARS FROM HIPPARCOS DATA. II. THE NATURE OF THE LOW-VELOCITY MOVING GROUPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bovy, Jo; Hogg, David W., E-mail: jo.bovy@nyu.ed

2010-07-10

The velocity distribution of nearby stars ({approx}<100 pc) contains many overdensities or 'moving groups', clumps of comoving stars, that are inconsistent with the standard assumption of an axisymmetric, time-independent, and steady-state Galaxy. We study the age and metallicity properties of the low-velocity moving groups based on the reconstruction of the local velocity distribution in Paper I of this series. We perform stringent, conservative hypothesis testing to establish for each of these moving groups whether it could conceivably consist of a coeval population of stars. We conclude that they do not: the moving groups are neither trivially associated with their eponymousmore » open clusters nor with any other inhomogeneous star formation event. Concerning a possible dynamical origin of the moving groups, we test whether any of the moving groups has a higher or lower metallicity than the background population of thin disk stars, as would generically be the case if the moving groups are associated with resonances of the bar or spiral structure. We find clear evidence that the Hyades moving group has higher than average metallicity and weak evidence that the Sirius moving group has lower than average metallicity, which could indicate that these two groups are related to the inner Lindblad resonance of the spiral structure. Further, we find weak evidence that the Hercules moving group has higher than average metallicity, as would be the case if it is associated with the bar's outer Lindblad resonance. The Pleiades moving group shows no clear metallicity anomaly, arguing against a common dynamical origin for the Hyades and Pleiades groups. Overall, however, the moving groups are barely distinguishable from the background population of stars, raising the likelihood that the moving groups are associated with transient perturbations.« less

Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity.

PubMed

Sousa, Cláudia; de Winter, Lenneke; Janssen, Marcel; Vermuë, Marian H; Wijffels, René H

2012-01-01

The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (P(O)₂= 0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06 day(-1), respectively. An increase of the P(CO)₂from 0.007 to 0.02 bar at P(O₂) of 0.84 bar resulted in an increase in the growth rate from 1.06 to 1.36 day(-1). These results confirm that the reduction of algal growth at high oxygen concentrations at sub-saturating light conditions is mainly caused by competitive inhibition of Rubisco. This negative effect on growth can be overcome by restoring the O(2)/CO(2) ratio by an increase in the partial carbon dioxide pressure. In comparison to general practice (P(O(2)) = 0.42 bar), working at partial O(2) pressure of 0.84 bar could reduce the energy requirement for degassing by a factor of 3-4. Copyright © 2011 Elsevier Ltd. All rights reserved.

Electromagnetic near-field coupling induced polarization conversion and asymmetric transmission in plasmonic metasurfaces

NASA Astrophysics Data System (ADS)

Peng, Yu-Xiang; Wang, Kai-Jun; He, Meng-Dong; Luo, Jian-Hua; Zhang, Xin-Min; Li, Jian-Bo; Tan, Shi-Hua; Liu, Jian-Qiang; Hu, Wei-Da; Chen, Xiaoshuang

2018-04-01

In this paper, we demonstrate the effect of polarization conversion in a plasmonic metasurface structure, in which each unit cell consists of a metal bar and four metal split-ring resonators (SRRs). Such effect is attributed to the fact that the dark plasmon mode of SRRs (bar), which radiates cross-polarized component, is induced by the bright plasmon mode of bar (SRRs) due to the electromagnetic near-field coupling between bar and SRRs. We find that there are two ways to achieve a large cross-polarized component in our proposed metasurface structure. The first way is realized when the dark plasmon mode of bar (SRRs) is in resonance, while at this time the bright plasmon mode of SRRs (bar) is not at resonant state. The second way is realized when the bright plasmon mode of SRRs (bar) is resonantly excited, while the dark plasmon mode of bar (SRRs) is at nonresonant state. It is also found that the linearly polarized light can be rotated by 56.50 after propagation through the metasurface structure. Furthermore, our proposed metasurface structure exhibits an asymmetric transmission for circularly polarized light. Our findings take a further step in developing integrated metasurface-based photonics devices for polarization manipulation and modulation.

GEO Optical Data Association with Concurrent Metric and Photometric Information

NASA Astrophysics Data System (ADS)

Dao, P.; Monet, D.

Data association in a congested area of the GEO belt with occasional visits by non-resident objects can be treated as a Multi-Target-Tracking (MTT) problem. For a stationary sensor surveilling the GEO belt, geosynchronous and near GEO objects are not completely motionless in the earth-fixed frame and can be observed as moving targets. In some clusters, metric or positional information is insufficiently accurate or up-to-date to associate the measurements. In the presence of measurements with uncertain origin, star tracks (residuals) and other sensor artifacts, heuristic techniques based on hard decision assignment do not perform adequately. In the MMT community, Bar-Shalom [2009 Bar-Shalom] was first in introducing the use of measurements to update the state of the target of interest in the tracking filter, e.g. Kalman filter. Following Bar-Shalom’s idea, we use the Probabilistic Data Association Filter (PDAF) but to make use of all information obtainable in the measurement of three-axis-stabilized GEO satellites, we combine photometric with metric measurements to update the filter. Therefore, our technique Concurrent Spatio- Temporal and Brightness (COSTB) has the stand-alone ability of associating a track with its identity –for resident objects. That is possible because the light curve of a stabilized GEO satellite changes minimally from night to night. We exercised COSTB on camera cadence data to associate measurements, correct mistags and detect non-residents in a simulated near real time cadence. Data on GEO clusters were used.

Shape distortions and Gestalt grouping in anorthoscopic perception

PubMed Central

Aydın, Murat; Herzog, Michael H.; Öğmen, Haluk

2011-01-01

When a figure moves behind a stationary narrow slit, observers often report seeing the figure as a whole, a phenomenon called slit viewing or anorthoscopic perception. Interestingly, in slit viewing, the figure is perceived compressed along the axis of motion. As with other perceptual distortions, it is unclear whether the perceptual space in the vicinity of the slit or the representation of the figure itself undergoes compression. In a psychophysical experiment, we tested these two hypotheses. We found that the percept of a stationary bar, presented within the slit, was not distorted even when at the same time a circle underwent compression by moving through the slit. This result suggests that the compression of form results from figural rather than from space compression. In support of this hypothesis, we found that when the bar was perceptually grouped with the circle, the bar appeared compressed. Our results show that, in slit viewing, the distortion occurs at a non-retinotopic level where grouped objects are jointly represented. PMID:19757947

fMRI identifies chronotype-specific brain activation associated with attention to motion--why we need to know when subjects go to bed.

PubMed

Reske, Martina; Rosenberg, Jessica; Plapp, Sabrina; Kellermann, Thilo; Shah, N Jon

2015-05-01

Human cognition relies on attentional capacities which, among others, are influenced by factors like tiredness or mood. Based on their inherent preferences in sleep and wakefulness, individuals can be classified as specific "chronotypes". The present study investigated how early, intermediate and late chronotypes (EC, IC, LC) differ neurally on an attention-to-motion task. Twelve EC, 18 IC and 17 LC were included into the study. While undergoing functional magnetic resonance imaging (fMRI) scans, subjects looked at vertical bars in an attention-to-motion task. In the STATIONARY condition, subjects focused on a central fixation cross. During Fix-MOVING and Attend-MOVING, bars were moving horizontally. Only during the Attend-MOVING, subjects were required to attend to changes in the velocity of bars and indicate those by button presses. A two-way repeated measures ANOVA probed group by attentional load effects. The dorsolateral prefrontal cortex (DLPFC), insula and anterior cingulate cortex showed group by attention specific activations. Specifically, EC and LC presented attenuated DLPFC activation under high attentional load (Attend-MOVING), while EC showed less anterior insula activation than IC. LC compared to IC exhibited attenuation of superior parietal cortex. Our study reveals that individual sleep preferences are associated with characteristic brain activation in areas crucial for attention and bodily awareness. These results imply that considering sleep preferences in neuroimaging studies is crucial when administering cognitive tasks. Our study also has socio-economic implications. Task performance in non-optimal times of the day (e.g. shift workers), may result in cognitive impairments leading to e.g. increased error rates and slower reaction times. Copyright © 2015 Elsevier Inc. All rights reserved.

Spectroscopy of snake states using a graphene Hall bar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milovanović, S. P., E-mail: slavisa.milovanovic@gmail.com; Ramezani Masir, M., E-mail: mrmphys@gmail.com; Peeters, F. M., E-mail: francois.peeters@ua.ac.be

2013-12-02

An approach to observe snake states in a graphene Hall bar containing a pn-junction is proposed. The magnetic field dependence of the bend resistance in a ballistic graphene Hall bar structure containing a tilted pn-junction oscillates as a function of applied magnetic field. We show that each oscillation is due to a specific snake state that moves along the pn-interface. Furthermore, depending on the value of the magnetic field and applied potential, we can control the lead in which the electrons will end up and hence control the response of the system.

Lateral masking in cycling displays: the relative importance of separation, flanker duration, and interstimulus interval for object-mediated updating.

PubMed

Hein, Elisabeth; Moore, Cathleen M

2010-01-01

A central bar repeatedly presented in alternation with two flanking bars can lead to the disappearance of the central bar. Recently it has been suggested that this masking effect could be explained by object-mediated updating: the information from the central bar is integrated into the representation of the flankers, leading not only to the disappearance of the central bar as a separate object, but also to the perception of the flankers in apparent motion between their real position and the position of the central bar. This account suggests that the visibility of the central bar should depend on the same factors as those that influence the construction and maintenance of object representations. Therefore separation between central bar and flankers should not influence visibility as long as the time interval between them is adequate to make an interpretation of the scene in terms of one object moving from one location to the other possible location. We found that if the time interval between the central bar and the flankers is neither too short nor too long, the central bar becomes invisible even at large separations. These findings are inconsistent with traditional accounts of the cycling lateral masking displays in terms of local inhibitory mechanisms.

Signatures of the Galactic bar on stellar kinematics unveiled by APOGEE

NASA Astrophysics Data System (ADS)

Palicio, Pedro A.; Martinez-Valpuesta, Inma; Prieto, Carlos Allende; Vecchia, Claudio Dalla; Zamora, Olga; Zasowski, Gail; Fernandez-Trincado, J. G.; Masters, Karen L.; García-Hernández, D. A.; Roman-Lopes, Alexandre

2018-05-01

Bars are common galactic structures in the local universe that play an important role in the secular evolution of galaxies, including the Milky Way. In particular, the velocity distribution of individual stars in our galaxy is useful to shed light on stellar dynamics, and provides information complementary to that inferred from the integrated light of external galaxies. However, since a wide variety of models reproduce the distribution of velocity and the velocity dispersion observed in the Milky Way, we look for signatures of the bar on higher-order moments of the line-of-sight velocity (V_los) distribution. We make use of two different numerical simulations -one that has developed a bar and one that remains nearly axisymmetric- to compare them with observations in the latest APOGEE data release (SDSS DR14). This comparison reveals three interesting structures that support the notion that the Milky Way is a barred galaxy. A high skewness region found at positive longitudes constrains the orientation angle of the bar, and is incompatible with the orientation of the bar at ℓ = 0° proposed in previous studies. We also analyse the V_los distributions in three regions, and introduce the Hellinger distance to quantify the differences among them. Our results show a strong non-Gaussian distribution both in the data and in the barred model, confirming the qualitative conclusions drawn from the velocity maps. In contrast to earlier work, we conclude it is possible to infer the presence of the bar from the kurtosis distribution.

Light-meson masses in an unquenched quark model

DOE PAGES

Chen, Xiaoyun; Ping, Jialun; Roberts, Craig D.; ...

2018-05-17

We perform a coupled-channels calculation of the masses of light mesons with the quantum numbers IJ P=-, (I,J) = 0,1, by includingmore » $$q\\bar{q}$$ and ($$q\\bar{q}$$) 2 components in a nonrelativistic chiral quark model. The coupling between two- and four-quark configurations is realized through a 3P 0 quark-pair creation model. With the usual form of this operator, the mass shifts are large and negative, an outcome which raises serious issues of validity for the quenched quark model. Therefore, we introduce some improvements of the 3P 0 operator in order to reduce the size of the mass shifts. By introducing two simple factors, physically well motivated, the coupling between $$q\\bar{q}$$ and ($$q\\bar{q}$$) 2 components is weakened, producing mass shifts that are around 10%–20% of hadron bare masses.« less

Light-meson masses in an unquenched quark model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xiaoyun; Ping, Jialun; Roberts, Craig D.

We perform a coupled-channels calculation of the masses of light mesons with the quantum numbers IJ P=-, (I,J) = 0,1, by includingmore » $$q\\bar{q}$$ and ($$q\\bar{q}$$) 2 components in a nonrelativistic chiral quark model. The coupling between two- and four-quark configurations is realized through a 3P 0 quark-pair creation model. With the usual form of this operator, the mass shifts are large and negative, an outcome which raises serious issues of validity for the quenched quark model. Therefore, we introduce some improvements of the 3P 0 operator in order to reduce the size of the mass shifts. By introducing two simple factors, physically well motivated, the coupling between $$q\\bar{q}$$ and ($$q\\bar{q}$$) 2 components is weakened, producing mass shifts that are around 10%–20% of hadron bare masses.« less

Signatures of the Galactic bar on stellar kinematics unveiled by APOGEE

NASA Astrophysics Data System (ADS)

Palicio, Pedro A.; Martinez-Valpuesta, Inma; Allende Prieto, Carlos; Dalla Vecchia, Claudio; Zamora, Olga; Zasowski, Gail; Fernandez-Trincado, J. G.; Masters, Karen L.; García-Hernández, D. A.; Roman-Lopes, Alexandre

2018-07-01

Bars are common galactic structures in the local universe that play an important role in the secular evolution of galaxies, including the Milky Way. In particular, the velocity distribution of individual stars in our galaxy is useful to shed light on stellar dynamics, and provides information complementary to that inferred from the integrated light of external galaxies. However, since a wide variety of models reproduce the distribution of velocity and the velocity dispersion observed in the Milky Way, we look for signatures of the bar on higher order moments of the line-of-sight velocity (V_{los}) distribution. We use two different numerical simulations - one that has developed a bar and one that remains nearly axisymmetric - to compare them with observations in the latest Apache Point Observatory Galactic Evolution Experiment data release (SDSS DR14). This comparison reveals three interesting structures that support the notion that the Milky Way is a barred galaxy. A high-skewness region found at positive longitudes constrains the orientation angle of the bar, and is incompatible with the orientation of the bar at ℓ = 0° proposed in previous studies. We also analyse the V_{los} distributions in three regions, and introduce the Hellinger distance to quantify the differences among them. Our results show a strong non-Gaussian distribution both in the data and in the barred model, confirming the qualitative conclusions drawn from the velocity maps. In contrast to earlier work, we conclude it is possible to infer the presence of the bar from the kurtosis distribution.

Experimental Study on Basic Mechanical Properties of BFRP Bars

NASA Astrophysics Data System (ADS)

Fan, Xiaochun; Xu, Ting; Zhou, Zhengrong; Zhou, Xun

2017-10-01

Basalt Fiber Reinforced Polymer (BFRP) bars have the advantages of corrosion resistance, high strength, light weight, good dielectric properties, and they are new type of green reinforced alternative material. In order to determine the mechanical properties of BFRP bars, the tensile strength of basalt fiber bars was necessary to be studied. The diameters of the basalt fiber bars were compared by means of uniaxial tensile test in this article. Then the stress-strain curve can be drawn out. The results show that the stress - strain curve of BFRP bars present straight line relation, and there is no sign before failure; there is no yield platform on the stress-strain curve of BFRP bars, which are typical brittle material;the tensile strength of BFRP bars is about 3 times higher than that of ordinary steel bars. and the elastic modulus is about 1/5 of that of ordinary steel; the ultimate tensile strength of BFRP bars varies little with the increase of diameter, but there exist some differences in modulus values.

Dark, Thin Fracture-Filling Material

NASA Image and Video Library

2015-11-11

These images and overlay bar charts from the Chemistry and Camera (ChemCam) instrument on NASA's Curiosity Mars rover indicate where some high-potassium material is localized within mineral veins at "Garden City." The two images are from ChemCam's Remote Micro-Imager. Each covers an area just over an inch wide (scale bars are in millimeters) in veins at the Garden City site on lower Mount Sharp. The overlay charts show comparisons of potassium (blue) and iron (red) in the mineral veins' compositions determined by reading the spectra of light induced by zapping points in each area with ChemCam's laser. Mineral veins such as these form where fluids move through fractured rocks, depositing minerals in the fractures and affecting chemistry of the surrounding rock. The thin layer of dark fracture-filling material in the image on the right contains much more potassium than the other local material on the left, indicating either different fluid compositions or local variations in the rock. The image on the left was taken on April 4, 2015, during the 946th Martian day, or sol, of Curiosity's work on Mars. The image on the right was taken on Sol 936, on March 25, 2015. A broader view of the prominent mineral veins at Garden City is at PIA19161. http://photojournal.jpl.nasa.gov/catalog/PIA19923

Chasing Shadows: Rotation of the Azimuthal Asymmetry in the TW Hya Disk

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debes, John H.; Poteet, Charles A.; Hines, Dean

2017-02-01

We have obtained new images of the protoplanetary disk orbiting TW Hya in visible, total intensity light with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope ( HST ), using the newly commissioned BAR5 occulter. These HST /STIS observations achieved an inner working angle of ∼0.″2, or 11.7 au, probing the system at angular radii coincident with recent images of the disk obtained by ALMA and in polarized intensity near-infrared light. By comparing our new STIS images to those taken with STIS in 2000 and with NICMOS in 1998, 2004, and 2005, we demonstrate that TW Hya’smore » azimuthal surface brightness asymmetry moves coherently in position angle. Between 50 au and 141 au we measure a constant angular velocity in the azimuthal brightness asymmetry of 22.°7 yr{sup −1} in a counterclockwise direction, equivalent to a period of 15.9 yr assuming circular motion. Both the (short) inferred period and lack of radial dependence of the moving shadow pattern are inconsistent with Keplerian rotation at these disk radii. We hypothesize that the asymmetry arises from the fact that the disk interior to 1 au is inclined and precessing owing to a planetary companion, thus partially shadowing the outer disk. Further monitoring of this and other shadows on protoplanetary disks potentially opens a new avenue for indirectly observing the sites of planet formation.« less

4. Light tower and keeper's house ,view west, southeast and ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Light tower and keeper's house ,view west, southeast and northeast sides - Baker Island Light, Lightkeeper's House, Just east of Cranberry Isles, at entrance to Frenchman Bay, Bar Harbor, Hancock County, ME

1. Keeper's house and light tower, view northeast, northwest and ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Keeper's house and light tower, view northeast, northwest and southwest sides - Baker Island Light, Lightkeeper's House, Just east of Cranberry Isles, at entrance to Frenchman Bay, Bar Harbor, Hancock County, ME

Mutual transformation of light waves by reflection holograms in photorefractive crystals of the 4-bar 3m symmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naunyka, V. N.; Shepelevich, V. V., E-mail: vasshep@inbox.ru

2011-05-15

The mutual transformation of light waves in the case of their simultaneous diffraction from a bulk reflection phase hologram, which was formed in a cubic photorefractive crystal of the 4-bar 3m symmetry class, has been studied. The indicator surfaces of the polarization-optimized values of the relative intensity of the object wave, which make it possible to determine the amplification of this wave for any crystal cut, are constructed. The linear polarization azimuths at which the energy exchange between the light waves reaches a maximum are found numerically for crystals of different cuts.

6. Light tower, detail of stairs leading from first landing ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Light tower, detail of stairs leading from first landing to cupola, looking east - Baker Island Light, Lightkeeper's House, Just east of Cranberry Isles, at entrance to Frenchman Bay, Bar Harbor, Hancock County, ME

5. Light tower and corner of keeper's house, view northeast, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Light tower and corner of keeper's house, view northeast, northwest and southwest sides - Baker Island Light, Lightkeeper's House, Just east of Cranberry Isles, at entrance to Frenchman Bay, Bar Harbor, Hancock County, ME

Visual Technology Research Simulator (VTRS) Human Performance Research: Phase III.

DTIC Science & Technology

1981-11-01

you will intercept the glideslope and a centered meatball at approximately 4500 feet from the ramp. When the meatball approaches centerball you are to...this system with two horizontal bars (to represent the datum bars) and a moving dot (referred to as the ball or the meatball ). The system is...At two balls low the meatball starts to flash. Plus or minus two balls is the maximum effective range of the system. The ball will be lost off the top

Measurement of elliptic flow of light nuclei at s N N = 200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV at the BNL Relativistic Heavy Ion Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.

Here we present measurements of second-order azimuthal anisotropy ( v 2 ) at midrapidity ( |y| < 1.0 ) for light nuclei d , t , 3He (formore » $$\\sqrt{s}$$$_{NN}$$ = 200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and antinuclei$$\\bar{d}$$ ( $$\\sqrt{s}$$$_{NN}$$ = 200 , 62.4, 39, 27, and 19.6 GeV) and 3 ¯¯¯¯¯ He ( $$\\sqrt{s}$$$_{NN}$$ = 200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The v 2 for these light nuclei produced in heavy-ion collisions is compared with those for p and $$\\bar{p}$$. We observe mass ordering in nuclei v 2 ( p T) at low transverse momenta ( p T < 2.0 GeV/c). We also find a centrality dependence of v 2 for d and $$\\bar{d}$$ . The magnitude of v 2 for t and 3He agree within statistical errors. Light-nuclei v 2 are compared with predictions from a blast-wave model. Atomic mass number ( A ) scaling of light-nuclei v 2 (p T) seems to hold for p T / A < 1.5 GeV/c . Results on light-nuclei v 2 from a transport-plus-coalescence model are consistent with the experimental measurements.« less

Measurement of elliptic flow of light nuclei at s N N = 200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV at the BNL Relativistic Heavy Ion Collider

DOE PAGES

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; ...

2016-09-23

Here we present measurements of second-order azimuthal anisotropy ( v 2 ) at midrapidity ( |y| < 1.0 ) for light nuclei d , t , 3He (formore » $$\\sqrt{s}$$$_{NN}$$ = 200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and antinuclei$$\\bar{d}$$ ( $$\\sqrt{s}$$$_{NN}$$ = 200 , 62.4, 39, 27, and 19.6 GeV) and 3 ¯¯¯¯¯ He ( $$\\sqrt{s}$$$_{NN}$$ = 200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The v 2 for these light nuclei produced in heavy-ion collisions is compared with those for p and $$\\bar{p}$$. We observe mass ordering in nuclei v 2 ( p T) at low transverse momenta ( p T < 2.0 GeV/c). We also find a centrality dependence of v 2 for d and $$\\bar{d}$$ . The magnitude of v 2 for t and 3He agree within statistical errors. Light-nuclei v 2 are compared with predictions from a blast-wave model. Atomic mass number ( A ) scaling of light-nuclei v 2 (p T) seems to hold for p T / A < 1.5 GeV/c . Results on light-nuclei v 2 from a transport-plus-coalescence model are consistent with the experimental measurements.« less

Smooth moves: bar and nightclub tobacco promotions that target young adults.

PubMed

Sepe, Edward; Ling, Pamela M; Glantz, Stanton A

2002-03-01

This article describes the tobacco industry's use of bars and nightclubs to encourage smoking among young adults. Previously secret tobacco industry marketing documents were analyzed. Tobacco industry bar and nightclub promotions in the 1980s and 1990s included aggressive advertising, tobacco brand--sponsored activities, and distribution of samples. Financial incentives for club owners and staff were used to encourage smoking through peer influence. Increased use of these strategies occurred concurrently with an increase in smoking among persons aged 18 through 24 years. The tobacco industry's bar and nightclub promotions are not yet politically controversial and are not regulated by the 1998 Master Settlement Agreement between the industry and the states. Tobacco control advocates should include young adults in research and advocacy efforts and should design interventions to counter this industry strategy to solidify smoking patterns and recruit young adult smokers.

Smooth Moves: Bar and Nightclub Tobacco Promotions That Target Young Adults

PubMed Central

Sepe, Edward; Ling, Pamela M.; Glantz, Stanton A.

2002-01-01

Objectives. This article describes the tobacco industry's use of bars and nightclubs to encourage smoking among young adults. Methods. Previously secret tobacco industry marketing documents were analyzed. Results. Tobacco industry bar and nightclub promotions in the 1980s and 1990s included aggressive advertising, tobacco brand–sponsored activities, and distribution of samples. Financial incentives for club owners and staff were used to encourage smoking through peer influence. Increased use of these strategies occurred concurrently with an increase in smoking among persons aged 18 through 24 years. Conclusions. The tobacco industry's bar and nightclub promotions are not yet politically controversial and are not regulated by the 1998 Master Settlement Agreement between the industry and the states. Tobacco control advocates should include young adults in research and advocacy efforts and should design interventions to counter this industry strategy to solidify smoking patterns and recruit young adult smokers. PMID:11867322

Former WWII Fighter Pilot Finds New Home Near Family

MedlinePlus

... Navigation Bar Home Current Issue Past Issues Feature: Senior Living Former WWII Fighter Pilot Finds New Home ... in Kalispell, Mont. Advice On a Move to Senior Living: Investigate your new surroundings. Talk to those ...

Coupled π π , K K ¯ scattering in P -wave and the ρ resonance from lattice QCD

DOE PAGES

Wilson, David J.; Briceño, Raúl A.; Dudek, Jozef J.; ...

2015-11-02

In this study, we determine elastic and coupled-channel amplitudes for isospin-1 meson-meson scattering inmore » $P$-wave, by calculating correlation functions using lattice QCD with light quark masses such that $$m_\\pi = 236$$ MeV in a cubic volume of $$\\sim (4 \\,\\mathrm{fm})^3$$. Variational analyses of large matrices of correlation functions computed using operator constructions resembling $$\\pi\\pi$$, $$K\\overline{K}$$ and $$q\\bar{q}$$, in several moving frames and several lattice irreducible representations, leads to discrete energy spectra from which scattering amplitudes are extracted. In the elastic $$\\pi\\pi$$ scattering region we obtain a detailed energy-dependence for the phase-shift, corresponding to a $$\\rho$$ resonance, and we extend the analysis into the coupled-channel $$K\\overline{K}$$ region for the first time, finding a small coupling between the channels.« less

Shoreface response and recovery to Hurricane Sandy: Fire Island, NY

USGS Publications Warehouse

Nelson, Timothy R.; Hapke, Cheryl J.; Wang, Ping; Rosati, Julie D.; Cheng, Jun

2015-01-01

The shoreface of Fire Island was extensively modified by Hurricane Sandy and subsequent storms in the following winter months. The changes were evaluated using various morphometrics of the shoreface from four bathymetric surveys, one prior to Hurricane Sandy, and three over the course of twenty months following Sandy. The datasets show that the nearshore bar system moved offshore to deeper water depths following Hurricane Sandy with volume lost from the subaerial beach and surfzone. Following the offshore shift, the nearshore bar system increased in size, the trough deepened, and there has been gradual landward movement of the nearshore bar. The steepening of the upper shoreface, landward translation of the profile, and loss of sediment is indicative of barrier island transgression.

Measurement of the top quark mass in the $$t\\bar{t}\\rightarrow\\text{ lepton+jets }$$→ and $$t\\bar{t}\\rightarrow\\text{dilepton}$$ → channels using $$\\sqrt{s}=7$$TeV ATLAS data

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2015-07-17

The top quark mass was measured in the channelsmore » $$t\\bar{t}$$→ lepton+jets and $$t\\bar{t}$$→ dilepton (lepton = e,μ) based on ATLAS data recorded in 2011. The data were taken at the LHC with a proton–proton centre-of-mass energy of √s = 7 TeV and correspond to an integrated luminosity of 4.6 fb –1. The $$t\\bar{t}$$→ lepton+jets analysis uses a three-dimensional template technique which determines the top quark mass together with a global jet energy scale factor (JSF), and a relative b-to-light-jet energy scale factor (bJSF), where the terms b-jets and light-jets refer to jets originating from b-quarks and u, d, c, s-quarks or gluons, respectively. The analysis of the $$t\\bar{t}$$→ dilepton channel exploits a one-dimensional template method using the m ℓb observable, defined as the average invariant mass of the two lepton+b-jet pairs in each event. The top quark mass is measured to be 172.33 ± 0.75 (stat + JSF + bJSF) ± 1.02(syst) GeV, and 173.79 ± 0.54(stat) ± 1.30(syst) GeV in the $$t\\bar{t}$$→ lepton+jets and $$t\\bar{t}$$→ dilepton channels, respectively. Thus, the combination of the two results yields m top = 172.99 ± 0.48(stat) ± 0.78(syst) GeV, with a total uncertainty of 0.91 GeV.« less

Monte Carlo simulation of a dynamical fermion problem: The light q sup 2 q sup 2 system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grondin, G.

1991-01-01

We present results from a Guided Random Walk Monte Carlo simulation of the light q{sup 2}{bar q}{sup 2} system in a Coulomb-plus-linear quark potential model using an Intel iPSC/860 hypercube. A solvable model problem is first considered, after which we study the full q{sup 2}{bar q}{sup 2} system in (J,I) = (2,2) and (2,0) sectors. We find evidence for no bound states below the vector-vector threshold in these systems. 17 refs., 6 figs.

Arrangement for multiplexing and intensity splitting light beams for interface into fiber optic cables

DOEpatents

Johnson, Steve A.

1990-01-01

An arrangement especially suitable for use in a laser apparatus for converting a plurality of different input light beams, for example copper vapor laser beams, into a plurality of substantially identical light beams is disclosed herein. This arrangement utilizes an optical mixing bar which is preferably integrally formed as a single unit and which includes a main body for mixing light therein, a flat input surface on one end of the main body, and a multi-faceted output face on the opposite end of the main body. This arrangement also includes means for directing the plurality of different input light beams onto the input face of the mixing base, whereby to cause the different beams to mix within the main body of the mixing bar and exit the latter from its multi-faceted output face as the desired plurality of substantially identical output beams.

33 CFR 162.134 - Connecting waters from Lake Huron to Lake Erie; traffic rules.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Regional Director General. (3) Between Fighting Island Channel South Light and Bar Point Pier Light 29D, no.... (4) Between the west end of Belle Isle and Peche Island Light, vessels may only overtake vessels... Light 2 and Russell Island Light 33, vessels may only overtake vessels engaged in towing. (2) Between...

33 CFR 162.134 - Connecting waters from Lake Huron to Lake Erie; traffic rules.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Regional Director General. (3) Between Fighting Island Channel South Light and Bar Point Pier Light 29D, no.... (4) Between the west end of Belle Isle and Peche Island Light, vessels may only overtake vessels... Light 2 and Russell Island Light 33, vessels may only overtake vessels engaged in towing. (2) Between...

Resonance Trapping in the Galactic Disc and Halo and its Relation with Moving Groups

NASA Astrophysics Data System (ADS)

Pichardo, Barbara; Moreno, Edmundo; william, schuster B.

2015-08-01

With the use of a detailed Milky Way nonaxisymmetric potential, observationally and dynamically constrained, the eects of the bar and the spiral arms in the Galaxy are studied in the disc and in the stellar halo. Especially the trapping of stars in the disk and Galactic halo by resonances on the Galactic plane created by the Galactic bar has been analysed in detail. To this purpose, a new method is presented to delineate the trapping regions using empirical diagrams of some orbital properties obtained in the Galactic potential. In these diagrams we plot in the inertial Galactic frame a characteristic orbital energy versus a characteristic orbital angular momentum, or versus the orbital Jacobi constant in the reference frame of the bar, when this is the only nonaxisymmetric component in the Galactic potential. With these diagrams some trapping regions are obtained in the disc and halo using a sample of disc stars and halo stars in the solar neighborhood. We compute several families of periodic orbits on the Galactic plane, some associated with this resonant trapping. In particular, we nd that the trapping eect of these resonances on the Galactic plane can extend some kpc from this plane, trapping stars in the Galactic halo. The purpose of our analysis is to investigate if the trapping regions contain some known moving groups in our Galaxy. We have applied our method to the Kapteyn group, a moving group in the halo, and we have found that this group appears not to be associated with a particular resonance on the Galactic plane.

THE MASS PROFILE AND SHAPE OF BARS IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G): SEARCH FOR AN AGE INDICATOR FOR BARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Taehyun; Lee, Myung Gyoon; Sheth, Kartik

2015-01-20

We have measured the radial light profiles and global shapes of bars using two-dimensional 3.6 μm image decompositions for 144 face-on barred galaxies from the Spitzer Survey of Stellar Structure in Galaxies. The bar surface brightness profile is correlated with the stellar mass and bulge-to-total (B/T) ratio of their host galaxies. Bars in massive and bulge-dominated galaxies (B/T > 0.2) show a flat profile, while bars in less massive, disk-dominated galaxies (B/T ∼ 0) show an exponential, disk-like profile with a wider spread in the radial profile than in the bulge-dominated galaxies. The global two-dimensional shapes of bars, however, are rectangular/boxy, independentmore » of the bulge or disk properties. We speculate that because bars are formed out of disks, bars initially have an exponential (disk-like) profile that evolves over time, trapping more disk stars to boxy bar orbits. This leads bars to become stronger and have flatter profiles. The narrow spread of bar radial profiles in more massive disks suggests that these bars formed earlier (z > 1), while the disk-like profiles and a larger spread in the radial profile in less massive systems imply a later and more gradual evolution, consistent with the cosmological evolution of bars inferred from observational studies. Therefore, we expect that the flatness of the bar profile can be used as a dynamical age indicator of the bar to measure the time elapsed since the bar formation. We argue that cosmic gas accretion is required to explain our results on bar profile and the presence of gas within the bar region.« less

Study of the weak annihilation contributions in charmless \\varvec{B_s→ VV} decays

NASA Astrophysics Data System (ADS)

Chang, Qin; Li, Xiaonan; Li, Xin-Qiang; Sun, Junfeng

2017-06-01

In this paper, in order to probe the spectator-scattering and weak annihilation contributions in charmless B_s→ VV (where V stands for a light vector meson) decays, we perform the χ ^2-analyses for the endpoint parameters within the QCD factorization framework, under the constraints from the measured \\bar{B}s→ ρ ^0φ , φ K^{*0}, φ φ and K^{*0}\\bar{K}^{*0} decays. The fitted results indicate that the endpoint parameters in the factorizable and nonfactorizable annihilation topologies are non-universal, which is also favored by the charmless B→ PP and PV (where P stands for a light pseudo-scalar meson) decays observed in previous work. Moreover, the abnormal polarization fractions f_{L,\\bot }(\\bar{B}s→ K^{*0}\\bar{K}^{*0})=(20.1± 7.0)%,(58.4± 8.5)% measured by the LHCb collaboration can be reconciled through the weak annihilation corrections. However, the branching ratio of \\bar{B}s→ φ K^{*0} decay exhibits a tension between the data and theoretical result, which dominates the contributions to χ _min^2 in the fits. Using the fitted endpoint parameters, we update the theoretical results for the charmless B_s→ VV decays, which will be further tested by the LHCb and Belle-II experiments in the near future.

Effect of E85 on RCCI Performance and Emissions on a Multi-Cylinder Light-Duty Diesel Engine - SAE World Congress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curran, Scott; Hanson, Reed M; Wagner, Robert M

2012-01-01

This paper investigates the effect of E85 on load expansion and FTP modal point emissions indices under reactivity controlled compression ignition (RCCI) operation on a light-duty multi-cylinder diesel engine. A General Motors (GM) 1.9L four-cylinder diesel engine with the stock compression ratio of 17.5:1, common rail diesel injection system, high-pressure exhaust gas recirculation (EGR) system and variable geometry turbocharger was modified to allow for port fuel injection with gasoline or E85. Controlling the fuel reactivity in-cylinder by the adjustment of the ratio of premixed low-reactivity fuel (gasoline or E85) to direct injected high reactivity fuel (diesel fuel) has been shownmore » to extend the operating range of high-efficiency clean combustion (HECC) compared to the use of a single fuel alone as in homogeneous charge compression ignition (HCCI) or premixed charge compression ignition (PCCI). The effect of E85 on the Ad-hoc federal test procedure (FTP) modal points is explored along with the effect of load expansion through the light-duty diesel speed operating range. The Ad-hoc FTP modal points of 1500 rpm, 1.0bar brake mean effective pressure (BMEP); 1500rpm, 2.6bar BMEP; 2000rpm, 2.0bar BMEP; 2300rpm, 4.2bar BMEP; and 2600rpm, 8.8bar BMEP were explored. Previous results with 96 RON unleaded test gasoline (UTG-96) and ultra-low sulfur diesel (ULSD) showed that with stock hardware, the 2600rpm, 8.8bar BMEP modal point was not obtainable due to excessive cylinder pressure rise rate and unstable combustion both with and without the use of EGR. Brake thermal efficiency and emissions performance of RCCI operation with E85 and ULSD is explored and compared against conventional diesel combustion (CDC) and RCCI operation with UTG 96 and ULSD.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aad, G.; Abbott, B.; Abdallah, J.

The top quark mass was measured in the channelsmore » $$t\\bar{t}$$→ lepton+jets and $$t\\bar{t}$$→ dilepton (lepton = e,μ) based on ATLAS data recorded in 2011. The data were taken at the LHC with a proton–proton centre-of-mass energy of √s = 7 TeV and correspond to an integrated luminosity of 4.6 fb –1. The $$t\\bar{t}$$→ lepton+jets analysis uses a three-dimensional template technique which determines the top quark mass together with a global jet energy scale factor (JSF), and a relative b-to-light-jet energy scale factor (bJSF), where the terms b-jets and light-jets refer to jets originating from b-quarks and u, d, c, s-quarks or gluons, respectively. The analysis of the $$t\\bar{t}$$→ dilepton channel exploits a one-dimensional template method using the m ℓb observable, defined as the average invariant mass of the two lepton+b-jet pairs in each event. The top quark mass is measured to be 172.33 ± 0.75 (stat + JSF + bJSF) ± 1.02(syst) GeV, and 173.79 ± 0.54(stat) ± 1.30(syst) GeV in the $$t\\bar{t}$$→ lepton+jets and $$t\\bar{t}$$→ dilepton channels, respectively. Thus, the combination of the two results yields m top = 172.99 ± 0.48(stat) ± 0.78(syst) GeV, with a total uncertainty of 0.91 GeV.« less

Lightweight device to stimulate and monitor human vestibulo-ocular reflex

NASA Technical Reports Server (NTRS)

McStravick, M. Catherine (Inventor); Proctor, David R. (Inventor); Wood, Scott J. (Inventor)

1989-01-01

A helmet formed of a rigid shell is disclosed. The shell is lined with several air filled bladders to contact firmly the head of a user. The shell has a rigid chin bar supporting a bite bar connected fixedly to a mouthpiece bearing against the teeth and hard palate to firmly anchor the helmet without movement. The outer shell surface supports various air pumping bulbs and accelerometers. Separate left and right visor pivot on the side guided in a central tongue and groove track to move optical lens mounts into the user's field of vision. The chin bar is connected to the shell by a pair of releasable clasps. A safety lanyard connects to the clasps to quickly pull pins from the clasps to enable quick release in case of motion sickness.

Output Error Analysis of Planar 2-DOF Five-bar Mechanism

NASA Astrophysics Data System (ADS)

Niu, Kejia; Wang, Jun; Ting, Kwun-Lon; Tao, Fen; Cheng, Qunchao; Wang, Quan; Zhang, Kaiyang

2018-03-01

Aiming at the mechanism error caused by clearance of planar 2-DOF Five-bar motion pair, the method of equivalent joint clearance of kinematic pair to virtual link is applied. The structural error model of revolute joint clearance is established based on the N-bar rotation laws and the concept of joint rotation space, The influence of the clearance of the moving pair is studied on the output error of the mechanis. and the calculation method and basis of the maximum error are given. The error rotation space of the mechanism under the influence of joint clearance is obtained. The results show that this method can accurately calculate the joint space error rotation space, which provides a new way to analyze the planar parallel mechanism error caused by joint space.

DETAIL VIEW OF BASE OF CAST IRON TOWER SHOWING THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL VIEW OF BASE OF CAST IRON TOWER SHOWING THE FABRICATING MARK OF STARBUCK IRON WORKS, TROY, NY - Bidwell Bar Suspension Bridge & Stone Toll House, Near Lake Oroville (moved from fork of Feather River), Oroville, Butte County, CA

Method and an apparatus to control the lateral motion of a long metal bar being formed by a mechanical process such as rolling or drawing

DOEpatents

Chang, Tzyy-Shuh; Huang, Hsun-Hau; Lin, Chang-Hung

2007-10-02

An adjustable guide, includes two or more mechanisms each having a rotatable retaining element containing a retaining groove with a variable radius in its perimeter surface. The grooves form a guidance path to control the lateral, i.e. non-axial, motion of a long bar moving along a longitudinal axis during a production process.The diameter of the guidance path varies according to the variable radii of the grooves. The guidance path increases in size at a predetermined rate, from a point of origin to an end point on the retaining groove. Rotating the retaining elements causes the diameter of the retaining grooves to change so that the size of the guidance path can be changed to match the diameter of the bar being rolled, size of the guidance path can be changed to fit the diameter of a new bar rolled without having to exchange the guide for a different sized guide, reduce fiction between the bar and the guide, a media, such as compressed air, can be injected between the retaining elements via orifices.Each retaining element is attached to a mounting apparatus. The mounting apparatus can be fixed or flexible. The flexible mounting apparatus includes one or more springs and one or more shock absorbers. A force neutral position of the flexible mounting apparatus is designed to be located on the predetermined ideal bar path line. The flexible mounting apparatus dissipates kinetic energy from the bar thereby reducing the bar's lateral motion relative to the ideal bar path line.The damping ratio of the mounting apparatus can be adjustable to alter the product's vibration mode to enable better control of the bar's lateral motion.

Parker Solar Probe Light Bar Test

NASA Image and Video Library

2018-06-05

In the Astrotech processing facility in Titusville, Florida, near NASA's Kennedy Space Center, on Tuesday, June 5, 2018, technicians and engineers perform light bar testing on NASA's Parker Solar Probe. The Parker Solar Probe will launch on a United Launch Alliance Delta IV Heavy rocket from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida no earlier than Aug. 4, 2018. The mission will perform the closest-ever observations of a star when it travels through the Sun's atmosphere, called the corona. The probe will rely on measurements and imaging to revolutionize our understanding of the corona and the Sun-Earth connection.

Effect of dynamic oxygen concentrations on the growth of Neochloris oleoabundans at sub-saturating light conditions.

PubMed

Sousa, Claudia; Valev, Dimitar; Vermuë, Marian H; Wijffels, Rene H

2013-08-01

In tubular photobioreactors micro-algae continuously experience dynamically changing oxygen and light conditions when circulating from the solar receiver to the dark degasser. These changes in oxygen concentration and light were simulated in a CSTR using sub-saturating light intensity. Elongation of the residence time in the solar receiver from 30 to 300 min was also investigated. Specific growth rates measured at constant low oxygen concentration PO2=0.21 bar were; 1.14 ± 0.06 day(-1) using continuous light 0.80 ± 0.16 day(-1) with 30 min light and 1.09 ± 0.05 day(-1) with 300 min light. The effect of dynamically changing oxygen concentrations from PO2=0.21 to 0.63 bar followed by degassing resulted in similar specific growth rates. The exposure of the algae cells to dark periods in the degasser has a bigger negative impact than the temporary exposure to accumulating oxygen concentrations in the solar receiver. This shows that considerable energy savings for degassing are possible. Copyright © 2013 Elsevier Ltd. All rights reserved.

Method and apparatus to control the lateral motion of a long metal bar being formed by a mechanical process such as rolling or drawing

DOEpatents

Chang, Tzyy-Shuh [Ann Arbor, MI; Huang, Hsun-Hau [Ann Arbor, MI; Lin, Chang-Hung [Ypsilanti, MI

2011-01-04

An apparatus to control lateral motion of a bar moving along a guidance path includes a pair of rotatable hubs each having at least first and second rollers at locations around the perimeter of the hub. The first roller has a first retaining groove of a first radius and the second roller has a second groove of a second radius smaller than the first radius. Each hub further includes at least one guiding element located between the rollers with a guide channel extending in the outer surface. A mounting system allows the hubs to be rotated between first and second positions. In the first position the first rollers oppose each other forming a guideway having a first, enlarged diameter for capturing a free end of an approaching bar. In the second position the second rollers form a second, smaller diameter to match the actual size of the bar.

An Elegant Galaxy in an Unusual Light

NASA Astrophysics Data System (ADS)

2010-09-01

A new image taken with the powerful HAWK-I camera on ESO's Very Large Telescope at Paranal Observatory in Chile shows the beautiful barred spiral galaxy NGC 1365 in infrared light. NGC 1365 is a member of the Fornax cluster of galaxies, and lies about 60 million light-years from Earth. NGC 1365 is one of the best known and most studied barred spiral galaxies and is sometimes nicknamed the Great Barred Spiral Galaxy because of its strikingly perfect form, with the straight bar and two very prominent outer spiral arms. Closer to the centre there is also a second spiral structure and the whole galaxy is laced with delicate dust lanes. This galaxy is an excellent laboratory for astronomers to study how spiral galaxies form and evolve. The new infrared images from HAWK-I are less affected by the dust that obscures parts of the galaxy than images in visible light (potw1037a) and they reveal very clearly the glow from vast numbers of stars in both the bar and the spiral arms. These data were acquired to help astronomers understand the complex flow of material within the galaxy and how it affects the reservoirs of gas from which new stars can form. The huge bar disturbs the shape of the gravitational field of the galaxy and this leads to regions where gas is compressed and star formation is triggered. Many huge young star clusters trace out the main spiral arms and each contains hundreds or thousands of bright young stars that are less than ten million years old. The galaxy is too remote for single stars to be seen in this image and most of the tiny clumps visible in the picture are really star clusters. Over the whole galaxy, stars are forming at a rate of about three times the mass of our Sun per year. While the bar of the galaxy consists mainly of older stars long past their prime, many new stars are born in stellar nurseries of gas and dust in the inner spiral close to the nucleus. The bar also funnels gas and dust gravitationally into the very centre of the galaxy, where astronomers have found evidence for the presence of a super-massive black hole, well hidden among myriads of intensely bright new stars. NGC 1365, including its two huge outer spiral arms, spreads over around 200 000 light-years. Different parts of the galaxy take different times to make a full rotation around the core of the galaxy, with the outer parts of the bar completing one circuit in about 350 million years. NGC 1365 and other galaxies of its type have come to more prominence in recent years with new observations indicating that the Milky Way could also be a barred spiral galaxy. Such galaxies are quite common - two thirds of spiral galaxies are barred according to recent estimates, and studying others can help astronomers understand our own galactic home. More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the world's largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

Touchscreen Tablets: Coordinating Action and Perception for Mathematical Cognition.

PubMed

Duijzer, Carolien A C G; Shayan, Shakila; Bakker, Arthur; Van der Schaaf, Marieke F; Abrahamson, Dor

2017-01-01

Proportional reasoning is important and yet difficult for many students, who often use additive strategies, where multiplicative strategies are better suited. In our research we explore the potential of an interactive touchscreen tablet application to promote proportional reasoning by creating conditions that steer students toward multiplicative strategies. The design of this application (Mathematical Imagery Trainer) was inspired by arguments from embodied-cognition theory that mathematical understanding is grounded in sensorimotor schemes. This study draws on a corpus of previously treated data of 9-11 year-old students, who participated individually in semi-structured clinical interviews, in which they solved a manipulation task that required moving two vertical bars at a constant ratio of heights (1:2). Qualitative analyses revealed the frequent emergence of visual attention to the screen location halfway along the bar that was twice as high as the short bar. The hypothesis arose that students used so-called "attentional anchors" (AAs)-psychological constructions of new perceptual structures in the environment that people invent spontaneously as their heuristic means of guiding effective manual actions for managing an otherwise overwhelming task, in this case keeping vertical bars at the same proportion while moving them. We assumed that students' AAs on the mathematically relevant points were crucial in progressing from additive to multiplicative strategies. Here we seek farther to promote this line of research by reanalyzing data from 38 students (aged 9-11). We ask: (1) What quantitative evidence is there for the emergence of AAs?; and (2) How does the transition from additive to multiplicative reasoning take place when solving embodied proportions tasks in interaction with the touchscreen tablet app? We found that: (a) AAs appeared for all students; (b) the AA-types were few across the students; (c) the AAs were mathematically relevant (top of the bars and halfway along the tall bar); (d) interacting with the tablet was crucial for the AAs' emergence; and (e) the vast majority of students progressed from additive to multiplicative strategies (as corroborated with oral utterances). We conclude that touchscreen applications have the potential to create interaction conditions for coordinating action and perception into mathematical cognition.

Touchscreen Tablets: Coordinating Action and Perception for Mathematical Cognition

PubMed Central

Duijzer, Carolien A. C. G.; Shayan, Shakila; Bakker, Arthur; Van der Schaaf, Marieke F.; Abrahamson, Dor

2017-01-01

Proportional reasoning is important and yet difficult for many students, who often use additive strategies, where multiplicative strategies are better suited. In our research we explore the potential of an interactive touchscreen tablet application to promote proportional reasoning by creating conditions that steer students toward multiplicative strategies. The design of this application (Mathematical Imagery Trainer) was inspired by arguments from embodied-cognition theory that mathematical understanding is grounded in sensorimotor schemes. This study draws on a corpus of previously treated data of 9–11 year-old students, who participated individually in semi-structured clinical interviews, in which they solved a manipulation task that required moving two vertical bars at a constant ratio of heights (1:2). Qualitative analyses revealed the frequent emergence of visual attention to the screen location halfway along the bar that was twice as high as the short bar. The hypothesis arose that students used so-called “attentional anchors” (AAs)—psychological constructions of new perceptual structures in the environment that people invent spontaneously as their heuristic means of guiding effective manual actions for managing an otherwise overwhelming task, in this case keeping vertical bars at the same proportion while moving them. We assumed that students’ AAs on the mathematically relevant points were crucial in progressing from additive to multiplicative strategies. Here we seek farther to promote this line of research by reanalyzing data from 38 students (aged 9–11). We ask: (1) What quantitative evidence is there for the emergence of AAs?; and (2) How does the transition from additive to multiplicative reasoning take place when solving embodied proportions tasks in interaction with the touchscreen tablet app? We found that: (a) AAs appeared for all students; (b) the AA-types were few across the students; (c) the AAs were mathematically relevant (top of the bars and halfway along the tall bar); (d) interacting with the tablet was crucial for the AAs’ emergence; and (e) the vast majority of students progressed from additive to multiplicative strategies (as corroborated with oral utterances). We conclude that touchscreen applications have the potential to create interaction conditions for coordinating action and perception into mathematical cognition. PMID:28228739

Tobacco free workplace policies and low socioeconomic status female bartenders in San Francisco.

PubMed

Moore, Roland S; Lee, Juliet P; Antin, Tamar M J; Martin, Scott E

2006-09-01

Multiple studies have found that, compared with employees in other settings, workers in bars and restaurants have been exposed to high levels of secondhand smoke, putting them at increased risk for health complications. Among these bar employees are many women of low socioeconomic status (SES). Smoke free workplace ordinances have been extended to bars and restaurants in cities and states throughout the USA; some bars, however, continue to be out of compliance with these laws. The objective of this study is to assess the relation between bartender gender and smoke free workplace compliance in bars. This paper reports on analyses of observational data on compliance with smoke free workplace policy in 121 randomly selected bars together with qualitative data from semi-structured interviews with bartenders and patrons in bars. San Francisco County bars. Findings from this research showed that smoke free policy non-compliance was associated with bars in which women were bartenders, increasing their tobacco exposure compared with male bartenders. In interviews, although some female bartenders expressed ambivalence toward the smoke free ordinance, many others described experiencing positive health and social consequences when the bars in which they worked could eliminate interior smoking. The analyses presented here shed light on the benefits of improving the workplace environment for low SES female bartenders through the extension of strong smoke free workplace policies to all workplaces, including bars.

Movement patterns of Bar-headed Geese Anser indicus during breeding and post-breeding periods at Qinghai Lake, China

USGS Publications Warehouse

Cui, Peng; Hou, Yuansheng; Tang, Mingjie; Zhang, Haiting; Zuohua, Yuanchun; Yin, Zuohua; Li, Tianxian; Guo, Shan; Xing, Zhi; He, Yubang; Prosser, Diann J.; Newman, Scott H.; Takekawa, John Y.; Yan, Baoping; Lei, Fumin

2011-01-01

The highly pathogenic avian influenza (HPAI) H5N1 outbreak at Qinghai Lake, China, in 2005 caused the death of over 6,000 migratory birds, half of which were Bar-headed Geese Anser indicus. Understanding the movements of this species may inform monitoring of outbreak risks for HPAI viruses; thus, we investigated the movement patterns of 29 Bar-headed Geese at Qinghai Lake, China during 2007 and 2008 by using high resolution GPS satellite telemetry. We described the movements and distribution of marked Bar-headed Geese during the pre-nesting, nesting, and moulting periods. Of 21 Bar-headed Geese with complete transmission records, 3 moved to other areas during the nesting period: 2 to Jianghe wetland (50 km northwest of Qinghai Lake) and 1 to Cuolongka Lake (220 km northwest of Qinghai Lake) during the nesting period. We identified nesting attempts of 7 of the marked geese at Qinghai Lake. Four completed successful nesting attempts according to our rules of judgment for the breeding status, and 2 geese lost broods soon after hatching (hereafter referred to as unsuccessful breeders). Of 18 geese present at Qinghai Lake during the nesting period, 9 (6 non-breeders, 2 successful breeders and 1 unsuccessful breeder) remained at Qinghai Lake during the moulting period; and 9 (5 non-breeders, 4 unsuccessful breeders) left Qinghai Lake for moulting. Kuhai Lake, Donggeicuona Lake, Alake Lake, Zhaling-Eling Lake area and Huangheyuan wetland area were used as moulting sites. Geese that moulted at Qinghai Lake, Cuolongka Lake, Kuhai Lake, Donggeicuona Lake and Alake Lake also moved to Zhaling-Eling Lake area or Huangheyuan wetland area and stayed there for several days prior to autumn migration. Mean home range and core area estimates did not differ significantly by sex, year and between breeders and non-breeders.

Movement patterns of Bar-headed Geese Anser indicus during breeding and post-breeding periods at Qinghai Lake, China

USGS Publications Warehouse

Cui, P.; Hou, Y.; Tang, M.; Zhang, H.; Zhou, Y.; Yin, Z.; Li, T.; Guo, S.; Xing, Z.; He, Y.; Prosser, D.J.; Newman, S.H.; Takekawa, John Y.; Yan, B.; Lei, F.

2011-01-01

The highly pathogenic avian influenza (HPAI) H5N1 outbreak at Qinghai Lake, China, in 2005 caused the death of over 6,000 migratory birds, half of which were Bar-headed Geese Anser indicus. Understanding the movements of this species may inform monitoring of outbreak risks for HPAI viruses; thus, we investigated the movement patterns of 29 Bar-headed Geese at Qinghai Lake, China during 2007 and 2008 by using high resolution GPS satellite telemetry. We described the movements and distribution of marked Bar-headed Geese during the pre-nesting, nesting, and moulting periods. Of 21 Bar-headed Geese with complete transmission records, 3 moved to other areas during the nesting period: 2 to Jianghe wetland (50 km northwest of Qinghai Lake) and 1 to Cuolongka Lake (220 km northwest of Qinghai Lake) during the nesting period. We identified nesting attempts of 7 of the marked geese at Qinghai Lake. Four completed successful nesting attempts according to our rules of judgment for the breeding status, and 2 geese lost broods soon after hatching (hereafter referred to as unsuccessful breeders). Of 18 geese present at Qinghai Lake during the nesting period, 9 (6 non-breeders, 2 successful breeders and 1 unsuccessful breeder) remained at Qinghai Lake during the moulting period; and 9 (5 non-breeders, 4 unsuccessful breeders) left Qinghai Lake for moulting. Kuhai Lake, Donggeicuona Lake, Alake Lake, Zhaling-Eling Lake area and Huangheyuan wetland area were used as moulting sites. Geese that moulted at Qinghai Lake, Cuolongka Lake, Kuhai Lake, Donggeicuona Lake and Alake Lake also moved to Zhaling-Eling Lake area or Huangheyuan wetland area and stayed there for several days prior to autumn migration. Mean home range and core area estimates did not differ significantly by sex, year and between breeders and non-breeders. ?? 2010 Dt. Ornithologen-Gesellschaft e.V.

Light-Drag Enhancement by a Highly Dispersive Rubidium Vapor.

PubMed

Safari, Akbar; De Leon, Israel; Mirhosseini, Mohammad; Magaña-Loaiza, Omar S; Boyd, Robert W

2016-01-08

The change in the speed of light as it propagates through a moving material has been a subject of study for almost two centuries. This phenomenon, known as the Fresnel light-drag effect, is quite small and usually requires a large interaction path length and/or a large velocity of the moving medium to be observed. Here, we show experimentally that the observed drag effect can be enhanced by over 2 orders of magnitude when the light beam propagates through a moving slow-light medium. Our results are in good agreement with the theoretical prediction, which indicates that, in the limit of large group indices, the strength of the light-drag effect is proportional to the group index of the moving medium.

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR LIGHT PEN OPERATION AND VERIFICATION OF SCANNED BAR CODES (UA-D-33.0)

EPA Science Inventory

The purpose of this SOP is to define the steps needed to operate the light pens, and verify the values produced by light pens used in the Arizona NHEXAS project and the "Border" study. Keywords: data; equipment; light pens.

The National Human Exposure Assessment Survey (NHEXAS)...

10. SOUTHEAST EXTERIOR CORNER. During demolition large iron bars were ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. SOUTHEAST EXTERIOR CORNER. During demolition large iron bars were found embedded in the south brick walls about 11 courses above the water table. These were possibly used to secure the roof structure of a shed which housed the fire engine of the Relief Fire Company (see Articles of Agreement, 1815, papers of the Central Philadelphia Meeting), which specified that the Engine House was to be situated at the northeast corner of the lot. Perhaps at some later date the shed was moved. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

House moves to block Internet censorship.

PubMed

Mirken, B

1995-08-18

Congress has created conflicting amendments to the Communications Decency Act, an amendment to the telecommunications deregulation bill. The Senate amendment contains sweeping language barring objectionable communications online. Observers fear this will block online distribution of AIDS prevention information as well as bar responses by activist's of drug companies and government officials. The House amendments seek to protect online services from liability if they restrict access to objectionable materials, while another amendment seeks to modify obscenity laws to criminalize only some forms of online speech. These conflicts are to be resolved in a House-Senate conference committee whose meeting date is yet to be decided.

A comparison of two soldering techniques on the misfit of bar-retained implant-supported overdentures.

PubMed

Alvarez, Angel; Lafita, Pedro; de Llanos, Hector; Gago, Angel; Brizuela, Aritza; Ellacuria, Joseba J

2014-02-01

This study was conducted to measure and compare the effect of the soldering method (torch soldering or ceramic furnace soldering) used for soldering bars to bar-retained, implant-supported overdentures on the fit between the bar gold cylinder and implant transgingival abutment. Thirty-two overdenture implant bars were manufactured and screw retained into two Bränemark implants, which were attached to a cow rib. The bars were randomly distributed in two groups: a torch-soldering group and a porcelain-furnace soldering group. Then all bars were cut and soldered using a torch and a ceramic furnace. The fit between the bar gold cylinders and implant transgingival abutments was measured with a light microscope on the opposite side to the screw tightening side before and after the bar soldering procedure. The data obtained were statistically processed for paired and independent data. The average misfit for all bars before soldering was 33.83 to 54.04 μm. After cutting and soldering the bars, the misfit increased up to a range of 71.74 to 78.79 μm. Both before and after the soldering procedure, the bars soldered using a torch showed a higher misfit when compared to the bars soldered using a porcelain furnace. After the soldering procedure, the misfit was slightly lower on the left side of the bars, which had been soldered using a ceramic furnace. According to our data, the soldering of bars using the torch or furnace oven soldering techniques does not improve the misfit of one-piece cast bars on two implants. The lower misfit was obtained using the porcelain furnace soldering technique. © 2013 by the American College of Prosthodontists.

The morphology and migration of transverse bars off the west-central Florida coast

USGS Publications Warehouse

Gelfenbaum, G.; Brooks, G.R.

2003-01-01

A series of migrating shore-normal sandbars with wavelengths of 75-120 m and heights up to 2 m have been identified off the northern tip of Anna Maria Island, a barrier island on the west-central Florida coast. Similar features have been described elsewhere since the 1930s and termed 'transverse bars'. The transverse bars identified off Anna Maria Island are found for about 3 km along the coast and extend 4 km offshore, well outside the normal surf-zone width. No cusps or any other associated beach expression is evident despite the fact that the bars come to within about 75 m of the beach. Sediments on the crests of the bars are a well-sorted fine quartz sand, whereas sediments in the troughs are a poorly sorted coarse carbonate shell hash. Historical aerial photographs and repeated high-resolution bathymetric surveys provide a means of quantifying the migration of the transverse bars. Analyses of orthorectified aerial photographs from the early 1940s through the mid 1990s clearly show movement or migration taking place in the bar field. In the 40-yr period from 1951 to 1991, the southern edge of the bar field moved 200-350 m to the south, with an average long-term migration rate of 8 m/yr. Repeated bathymetric surveys over an 8-month period give an average short-term migration rate of 21 m/yr to the south. Wave and current measurements suggest that southerly winds associated with the passage of cold fronts drive near-bed currents to the south that are strong enough to initiate sediment transport and cause the southerly migration of the transverse bars.

Burst-by-burst laser frequency monitor

NASA Technical Reports Server (NTRS)

Esproles, Carlos (Inventor)

1994-01-01

The invention is a system for real-time frequency monitoring and display of an RF burst where the burst frequency is analyzed and displayed on a burst-by-burst basis in order to allow for frequency control. Although the invention was made for monitoring the laser frequency of a LIDAR system, it has other applications where realtime monitoring is required. The novelty of the invention resides in the use of a counter that is reset at the beginning of each unit time of monitoring and then gated for a unit of time. The invention also has an LED bar graph for displaying the measure of frequency at the end of each unit time in either a bar length mode or a moving dot mode. In the latter mode, the operator makes necessary adjustments to maintain the dot at the center of the bar graph.

Probing lepton-flavour universality with K→ π ν \\bar{ν } decays

NASA Astrophysics Data System (ADS)

Bordone, Marzia; Buttazzo, Dario; Isidori, Gino; Monnard, Joachim

2017-09-01

We analyse the rare processes K→ π ν \\bar{ν } in view of the recent hints of violations of lepton-flavour universality (LFU) observed in B meson decays. If, as suggested by present data, the new interactions responsible for LFU violations couple mainly to the third generation of left-handed fermions, K→ π ν \\bar{ν } decays turn out to be particularly interesting: these are the only kaon decays with third-generation leptons (the τ neutrinos) in the final state. In order to relate B-physics anomalies and K decays we adopt an effective field theory approach, assuming that the new interactions satisfy an approximate U(2)_q× U(2)_ℓ flavour symmetry. In this framework we show that O(1) deviations from the Standard Model predictions in K→ π ν \\bar{ν } branching ratios, closely correlated to similar effects in B→ K^{(*)}ν \\bar{ν }, are naturally expected. The correlation of B(K → π ν \\bar{ν }), B(B→ K^{(*)}ν \\bar{ν }), and the LFU violations in B decays would provide a very valuable tool to shed more light on this interesting phenomenon.

Reading Three Israeli Bat/Bar Mitzvah Curricula as Gender, Theological, and Autobiographical Texts

ERIC Educational Resources Information Center

Bacon, Brenda Socachevsky

2008-01-01

This article analyzes three curricula for the bat/bar-mitzvah year of the public religious, Tali and public schools in Israel. It compares their views on gender and theology, and throws light on the intersection of gender, religion and education in Israeli society. It shows how the messages of the public religious and public schools serve to…

Modeling the Elastic and Damping Properties of the Multilayered Torsion Bar-Blade Structure of Rotors of Light Helicopters of the New Generation 2. Finite-Element Approximation of Blades and a Model of Coupling of the Torsion Bar with the Blades

NASA Astrophysics Data System (ADS)

Paimushin, V. N.; Shishkin, V. M.

2016-01-01

A rod-shape finite element with twelve degrees of freedom is proposed for modeling the elastic and damping properties of rotor blades with regard to their geometric stiffness caused by rotation of the rotor. A model of coupling of the torsion bar with blades is developed based on the hypothesis of linear deplanation of the connecting section of the torsion bar and a special transition element to ensure the compatibility of displacements of the torsion bar and blades upon their vibrations in the flapping and rotation planes. Numerical experiments were carried out to test and assess the validity of the model developed. Suggestions are made for ensuring unconditional stability of the iteration method in a subspace in determining the specified number of modes and frequencies of free vibrations of the torsion bar-blade structure.

Light-quark, heavy-quark systems: An update

NASA Astrophysics Data System (ADS)

Grinstein, B.

1993-06-01

We review many of the recently developed applications of Heavy Quark Effective Theory techniques. After a brief update on Luke's theorem, we describe striking relations between heavy baryon form factors, and how to use them to estimate the accuracy of the extraction of (vert bar)V(sub cb)(vert bar). We discuss factorization and compare with experiment. An elementary presentation, with sample applications, of reparametrization invariance comes next. The final and most extensive chapter in this review deals with phenomenological lagrangians that incorporate heavy-quark spin-flavor as well as light quark chiral symmetries. We compile many interesting results and discuss the validity of the calculations.

Modeling the Elastic and Damping Properties of the Multilayered Torsion Bar-Blade Structure of Rotors of Light Helicopters of the New Generation. 1. Finite-Element Approximation of the Torsion Bar

NASA Astrophysics Data System (ADS)

Paimushin, V. N.; Shishkin, V. M.

2015-11-01

A prismatic semiquadratic element with a nonclassical approximation of its displacements is suggested for modeling the composite and soft layers of a torsion bar and multilayered plate-rod structures. The stiffness, weight, damping, and geometric stiffness matrices of the above-mentioned element are obtained. Expressions for computing stresses in the finite element under the action of static loads and vibrations in the resonance zone are presented. Test examples confirming the validity of the element suggested are given. An example of finite element determination of the dynamic response of a multilayered torsion bar in the resonant mode is considered.

Effect of flaxseed flour incorporation on the physical properties and consumer acceptability of cereal bars.

PubMed

Khouryieh, H; Aramouni, F

2013-12-01

Extensive research has revealed numerous nutritional and health benefits of flaxseed due primarily to its nutrients content. The objective of this study was to evaluate the effect of flaxseed flour addition on the physical and sensory characteristics of cereal bars. Four formulations of the flaxseed cereal bars were prepared by partially replacing oats with flaxseed flour added at levels of 0 (control), 6%, 12% and 18%. There were no significant differences (p > 0.05) in water activity, moisture and firmness values between the flaxseed bars and control. Flaxseed addition significantly (p < 0.05) decreased lightness and increased redness of the bars. There were no significant differences (p > 0.05) between the 12% flax cereal bars and the control with respect to sensory attributes and overall acceptability. The overall acceptability for both 12% flax bars and the control was in between 'like moderately' and 'like slightly' on the 9-point hedonic scale. The overall acceptability was most highly correlated with flavor acceptability for both control (r = 0.80) and 12% flax (r = 0.82) cereal bars. Flaxseed bars provided 12% dietary fiber of the daily recommended value. These results indicated that flaxseed flour incorporation up to 12% substantially enhanced the nutritional qualities of the cereal bars without affecting their sensory and quality properties.

Nondestructive evaluation of epoxy-coated reinforcing bars in concrete using bi-electrode half-cell potential techniques.

DOT National Transportation Integrated Search

2006-01-01

This study evaluated two half-cell mapping methods for nondestructive evaluation of epoxy-coated rebar (ECR) in concrete: the semi-fixed bi-electrode and the moving bi-electrode methods. These methods were expected to provide early detection of corro...

A BRIGHT RING OF STAR BIRTH AROUND A GALAXY'S CORE

NASA Technical Reports Server (NTRS)

2002-01-01

n image from NASA's Hubble Space Telescope reveals clusters of infant stars that formed in a ring around the core of the barred-spiral galaxy NGC 4314. This stellar nursery, whose inhabitants were created within the past 5 million years, is the only place in the entire galaxy where new stars are being born. The Hubble image is being presented today (June 11) at the American Astronomical Society meeting in San Diego, Calif. This close-up view by Hubble also shows other interesting details in the galaxy's core: dust lanes, a smaller bar of stars, dust and gas embedded in the stellar ring, and an extra pair of spiral arms packed with young stars. These details make the center resemble a miniature version of a spiral galaxy. While it is not unusual to have dust lanes and rings of gas in the centers of galaxies, it is uncommon to have spiral arms full of young stars in the cores. NGC 4314 is one of the nearest (only 40 million light-years away in the constellation Coma Berenices) examples of a galaxy with a ring of infant stars close to the core. This stellar ring - whose radius is 1,000 light-years - is a great laboratory to study star formation in galaxies. The left-hand image, taken in February 1996 by the 30-inch telescope Prime Focus Camera at the McDonald Observatory in Texas, shows the entire galaxy, including the bar of stars bisecting the core and the outer spiral arms, which begin near the ends of this bar. The box around the galaxy's core pinpoints the focus of the Hubble image. The right-hand image shows Hubble's close-up view of the galaxy's core, taken in December 1995 by the Wide Field and Planetary Camera 2. The bluish-purple clumps that form the ring are the clusters of infant stars. Two dark, wispy lanes of dust and a pair of blue spiral arms are just outside the star-forming ring. The lanes of dust are being shepherded into the ring by the longer, primary stellar bar seen in the ground-based (left-hand) image. The gas is trapped inside the ring through the stars' gravitational attraction. The two spiral arms outside the ring are probably unrelated to the dust lanes, and seem to contain very little dust or gas. The stars in these spiral arms are bluer than most of the galaxy, indicating that many of them are relatively young, less than 200 million years old. However, they are older than those in the ring. This information suggests that the neighborhood of star formation is moving closer to the galaxy's core. Another interpretation has the arms formed through the gravitational interaction of the embedded bar and ring of stars, causing them to spray outward. This picture was created by combining images taken in ultraviolet, blue, visible, infrared, and H-alpha. The purple color represents hydrogen gas being excited by hot, young star clusters. Credits: G. Fritz Benedict, Andrew Howell, Inger Jorgensen, David Chapell (University of Texas), Jeffery Kenney (Yale University), and Beverly J. Smith (CASA, University of Colorado), and NASA. We gratefully acknowledge the support of the Hubble Space Telescope Astrometry Science Team: Principal Investigator W.H. Jefferys, R. Duncombe, P. Shelus, B. McArthur (University of Texas), P. Hemenway (University of Rhode Island), O. Franz (Lowell Observatory), A. Whipple (Allied-Signal Corp.), Wm. van Altena (Yale University), and, L. Fredrick (University of Virginia).

Tobacco free workplace policies and low socioeconomic status female bartenders in San Francisco

PubMed Central

Moore, Roland S; Lee, Juliet P; Antin, Tamar M J; Martin, Scott E

2006-01-01

Study objective Multiple studies have found that, compared with employees in other settings, workers in bars and restaurants have been exposed to high levels of secondhand smoke, putting them at increased risk for health complications. Among these bar employees are many women of low socioeconomic status (SES). Smoke free workplace ordinances have been extended to bars and restaurants in cities and states throughout the USA; some bars, however, continue to be out of compliance with these laws. The objective of this study is to assess the relation between bartender gender and smoke free workplace compliance in bars. Design This paper reports on analyses of observational data on compliance with smoke free workplace policy in 121 randomly selected bars together with qualitative data from semi‐structured interviews with bartenders and patrons in bars. Setting San Francisco County bars. Main results Findings from this research showed that smoke free policy non‐compliance was associated with bars in which women were bartenders, increasing their tobacco exposure compared with male bartenders. In interviews, although some female bartenders expressed ambivalence toward the smoke free ordinance, many others described experiencing positive health and social consequences when the bars in which they worked could eliminate interior smoking. Conclusions The analyses presented here shed light on the benefits of improving the workplace environment for low SES female bartenders through the extension of strong smoke free workplace policies to all workplaces, including bars. PMID:17708011

Kupier prize lecture: Sources of solar-system carbon

NASA Technical Reports Server (NTRS)

Anders, Edward; Zinner, Ernst

1994-01-01

We have tried to deconvolve Solar-System carbon into its sources, on the basis of C-12/C-13 ratios (equivalent to R). Interstellar SiC in meteorites, representing greater than 4.6-Ga-old stardust from carbon stars, is isotopically heavier (bar R = 38 +/- 2) than Solar-System carbon (89), implying that the latter contains an additional, light component. A likely source are massive stars, mainly Type II supernovae and Wolf-Rayet stars, which, being O-rich, eject their C largely as CO rather than carbonaceous dust. The fraction of such light C in the Solar System depends on R(sub light) in the source. For R(sub light) = 180-1025 (as in 'Group 4' meteoritic graphite spherules, which apparently came from massive stars greater than 4.6 Ga ago), the fraction of light C is 0.79-0.61. Similar results are obtained for present-day data on red giants and interstellar gas. Although both have become enriched in C-13 due to galactic evolution (to bar-R = 20 and 57), the fraction of the light component in interstellar gas again is near 0.7. (Here bar R represents the mean of a mixture calculated via atom fractions; it is not identical to the arithmetic mean R). Interstellar graphite, unlike SiC, shows a large peak at R approximately equal 90, near the solar value. Although some of the grains may be of local origin, others show anomalies in other elements and hence are exotic. Microdiamonds, with R = 93, also are exotic on the basis of their Xe and N. Apparently R approximately 90 was a fairly common composition 4.6 Ga ago, of stars as well as the ISM.

Automatic ball bar for a coordinate measuring machine

DOEpatents

Jostlein, H.

1997-07-15

An automatic ball bar for a coordinate measuring machine determines the accuracy of a coordinate measuring machine having at least one servo drive. The apparatus comprises a first and second gauge ball connected by a telescoping rigid member. The rigid member includes a switch such that inward radial movement of the second gauge ball relative to the first gauge ball causes activation of the switch. The first gauge ball is secured in a first magnetic socket assembly in order to maintain the first gauge ball at a fixed location with respect to the coordinate measuring machine. A second magnetic socket assembly secures the second gauge ball to the arm or probe holder of the coordinate measuring machine. The second gauge ball is then directed by the coordinate measuring machine to move radially inward from a point just beyond the length of the ball bar until the switch is activated. Upon switch activation, the position of the coordinate measuring machine is determined and compared to known ball bar length such that the accuracy of the coordinate measuring machine can be determined. 5 figs.

Automatic ball bar for a coordinate measuring machine

DOEpatents

Jostlein, Hans

1997-01-01

An automatic ball bar for a coordinate measuring machine determines the accuracy of a coordinate measuring machine having at least one servo drive. The apparatus comprises a first and second gauge ball connected by a telescoping rigid member. The rigid member includes a switch such that inward radial movement of the second gauge ball relative to the first gauge ball causes activation of the switch. The first gauge ball is secured in a first magnetic socket assembly in order to maintain the first gauge ball at a fixed location with respect to the coordinate measuring machine. A second magnetic socket assembly secures the second gauge ball to the arm or probe holder of the coordinate measuring machine. The second gauge ball is then directed by the coordinate measuring machine to move radially inward from a point just beyond the length of the ball bar until the switch is activated. Upon switch activation, the position of the coordinate measuring machine is determined and compared to known ball bar length such that the accuracy of the coordinate measuring machine can be determined.

Electromagnetic energy harvesting from a dual-mass pendulum oscillator

NASA Astrophysics Data System (ADS)

Wang, Hongyan; Tang, Jiong

2016-04-01

This paper presents the analysis of a type of vibration energy harvester composed of an electromagnetic pendulum oscillator combined to an elastic main structure. In this study, the elastic main structure connected to the base is considered as a single degree-of-freedom (DOF) spring-mass-damper subsystem. The electromagnetic pendulum oscillator is considered as a dual-mass two-frequency subsystem, which is composed of a hollow bar with a tip winded coil and a magnetic mass with a spring located in the hollow bar. As the pendulum swings, the magnetic mass can move along the axial direction of the bar. Thus, the relative motion between the magnet and the coil induces a wire current. A mathematical model of the coupled system is established. The system dynamics a 1:2:1 internal resonance. Parametric analysis is carried out to demonstrate the effect of the excitation acceleration, excitation frequency, load resistance, and frequency tuning parameters on system performance.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR LIGHT PEN OPERATION AND VERIFICATION OF SCANNED BAR CODES (UA-D-33.0)

EPA Science Inventory

The purpose of this SOP is to define the steps needed to operate the light pens, and verify the values produced by light pens used in the Arizona NHEXAS project and the Border study. Keywords: data; equipment; light pens.

The U.S.-Mexico Border Program is sponsored by the Envir...

Aperture synthesis observations of CO emission from the Nucleus of IC 342

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lo, K.Y.; Berge, G.L.; Claussen, M.J.

1984-07-15

We present the first aperture synthesis maps of lambda2.6 mm CO (J = 1-0) emission from an external galaxy, IC 342. The 7'' resolution maps of the nuclear region were made with the Owens Valley Millimeter-Wave Interferometr. They reveal that the CO source is distributed in a bar, 300 pc x > or approx. =1500 pc, with a veloity gradient across the width of the bar. The observations suggest that the molecular gas in the nucleus is moving in response to an oval gravitational potential. The implications of an oval potential on enhanced star formation and other activities are discussed.

The electromagnetic multipole moments of the charged open-flavor {Z}_{\\bar{c}q} states

NASA Astrophysics Data System (ADS)

Azizi, K.; Özdem, U.

2018-05-01

The electromagnetic multipole moments of the open-flavor {Z}\\bar{cq} states are investigated by assuming a diquark–antidiquark picture for their internal structure and quantum numbers {J}{PC}={1}+- for their spin-parity. In particular, their magnetic and quadrupole moments are extracted in the framework of light-cone QCD sum rule by the help of the photon distribution amplitudes. The electromagnetic multipole moments of the open-flavor {Z}\\bar{cq} states are important dynamical observables, which encode valuable information on their underlying structure. The results obtained for the magnetic moments of different structures are considerably large and can be measured in future experiments. We obtain very small values for the quadrupole moments of {Z}\\bar{cq} states indicating a nonspherical charge distribution.

The opercular mouth-opening mechanism of largemouth bass functions as a 3D four-bar linkage with three degrees of freedom.

PubMed

Olsen, Aaron M; Camp, Ariel L; Brainerd, Elizabeth L

2017-12-15

The planar, one degree of freedom (1-DoF) four-bar linkage is an important model for understanding the function, performance and evolution of numerous biomechanical systems. One such system is the opercular mechanism in fishes, which is thought to function like a four-bar linkage to depress the lower jaw. While anatomical and behavioral observations suggest some form of mechanical coupling, previous attempts to model the opercular mechanism as a planar four-bar have consistently produced poor model fits relative to observed kinematics. Using newly developed, open source mechanism fitting software, we fitted multiple three-dimensional (3D) four-bar models with varying DoF to in vivo kinematics in largemouth bass to test whether the opercular mechanism functions instead as a 3D four-bar with one or more DoF. We examined link position error, link rotation error and the ratio of output to input link rotation to identify a best-fit model at two different levels of variation: for each feeding strike and across all strikes from the same individual. A 3D, 3-DoF four-bar linkage was the best-fit model for the opercular mechanism, achieving link rotational errors of less than 5%. We also found that the opercular mechanism moves with multiple degrees of freedom at the level of each strike and across multiple strikes. These results suggest that active motor control may be needed to direct the force input to the mechanism by the axial muscles and achieve a particular mouth-opening trajectory. Our results also expand the versatility of four-bar models in simulating biomechanical systems and extend their utility beyond planar or single-DoF systems. © 2017. Published by The Company of Biologists Ltd.

Hadro-quarkonia dynamics and Z{sub b} states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Danilkin, I. V.; Orlovsky, V. D., E-mail: orlovskii@itep.ru; Simonov, Yu. A.

2013-09-15

Dynamics of hadro-quarkonium system is formulated, based on the channel coupling of a light hadron (h) and heavy quarkonium (QQ-bar) to heavy-light mesons (Qq-bar, Q-barq). Equations for hadro-quarkonium amplitudes and resonance positions are written explicitly, and numerically calculated for the special case of {pi} Greek-Upsilon-With-Hook-Symbol (nS) (n = 1, 2, 3). It is also shown that the recently observed by Belle two peaks Z{sub b}(10610) and Z{sub b}(10650) are in agreement with the proposed theory. It is demonstrated that theory predicts peaks at the BB*, B*B* thresholds in all available {pi} Greek-Upsilon-With-Hook-Symbol (nS) channels.

Scale dependence of open c{\\bar{c}} and b{\\bar{b}} production in the low x region

NASA Astrophysics Data System (ADS)

Oliveira, E. G. de; Martin, A. D.; Ryskin, M. G.

2017-03-01

The `optimal' factorization scale μ _0 is calculated for open heavy quark production. We find that the optimal value is μ _F=μ _0˜eq 0.85√{p^2_T+m_Q^2} ; a choice which allows us to resum the double-logarithmic, (α _s ln μ ^2_F ln (1/x))^n corrections (enhanced at LHC energies by large values of ln (1/x)) and to move them into the incoming parton distributions, PDF(x,μ _0^2). Besides this result for the single inclusive cross section (corresponding to an observed heavy quark of transverse momentum p_T), we also determined the scale for processes where the acoplanarity can be measured; that is, events where the azimuthal angle between the quark and the antiquark may be determined experimentally. Moreover, we discuss the important role played by the 2→ 2 subprocesses, gg→ Q\\bar{Q} at NLO and higher orders. In summary, we achieve a better stability of the QCD calculations, so that the data on c{\\bar{c}} and b{\\bar{b}} production can be used to further constrain the gluons in the small x, relatively low scale, domain, where the uncertainties of the global analyses are large at present.

Redshift distortions of galaxy correlation functions

NASA Technical Reports Server (NTRS)

Fry, J. N.; Gaztanaga, Enrique

1994-01-01

To examine how peculiar velocities can affect the two-, three-, and four-point redshift correlation functions, we evaluate volume-average correlations for configurations that emphasize and minimize redshift distortions for four different volume-limited samples from each of the CfA, SSRS, and IRAS redshift catalogs. We present the results as the correlation length r(sub 0) and power index gamma of the two-point correlations, bar-xi(sub 0) = (r(sub 0)/r)(exp gamma), and as the hierarchical amplitudes of the three- and four-point functions, S(sub 3) = bar-xi(sub 3)/bar-xi(exp 2)(sub 2) and S(sub 4) = bar-xi(sub 4)/bar-xi(exp 3)(sub 2). We find a characteristic distortion for bar-xi(sub 2), the slope gamma is flatter and the correlation length is larger in redshift space than in real space; that is, redshift distortions 'move' correlations from small to large scales. At the largest scales (up to 12 Mpc), the extra power in the redshift distribution is compatible with Omega(exp 4/7)/b approximately equal to 1. We estimate Omega(exp 4/7)/b to be 0.53 +/- 0.15, 1.10 +/- 0.16, and 0.84 +/- 0.45 for the CfA, SSRS, and IRAS catalogs. Higher order correlations bar-xi(sub 3) and bar-xi(sub 4) suffer similar redshift distortions but in such a way that, within the accuracy of our ananlysis, the normalized amplitudes S(sub 3) and S(sub 4) are insensitive to this effect. The hierarchical amplitudes S(sub 3) and S(sub 4) are constant as a function of scale between 1 and 12 Mpc and have similar values in all samples and catalogs, S(sub 3) approximately equal to 2 and S(sub 4) approximately equal to 6, despite the fact that bar-xi(sub 2), bar-xi(sub 3), and bar-xi(sub 4) differ from one sample to another by large factors (up to a factor of 4 in bar-xi(sub 2), 8 for bar-xi(sub 3), and 12 for bar-xi(sub 4)). The agreement between the independent estimations of S(sub 3) and S(sub 4) is remarkable given the different criteria in the selection of galaxies and also the difference in the resulting range of densities, luminosities, and locations between samples.

PDZ binding to the BAR domain of PICK1 is elucidated by coarse-grained molecular dynamics.

PubMed

He, Yi; Liwo, Adam; Weinstein, Harel; Scheraga, Harold A

2011-01-07

A key regulator of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor traffic, PICK1 is known to interact with over 40 other proteins, including receptors, transporters and ionic channels, and to be active mostly as a homodimer. The current lack of a complete PICK1 structure determined at atomic resolution hinders the elucidation of its functional mechanisms. Here, we identify interactions between the component PDZ and BAR domains of PICK1 by calculating possible binding sites for the PDZ domain of PICK1 (PICK1-PDZ) to the homology-modeled, crescent-shaped dimer of the PICK1-BAR domain using multiplexed replica-exchange molecular dynamics (MREMD) and canonical molecular dynamics simulations with the coarse-grained UNRES force field. The MREMD results show that the preferred binding site for the single PDZ domain is the concave cavity of the BAR dimer. A second possible binding site is near the N-terminus of the BAR domain that is linked directly to the PDZ domain. Subsequent short canonical molecular dynamics simulations used to determine how the PICK1-PDZ domain moves to the preferred binding site on the BAR domain of PICK1 revealed that initial hydrophobic interactions drive the progress of the simulated binding. Thus, the concave face of the BAR dimer accommodates the PDZ domain first by weak hydrophobic interactions and then the PDZ domain slides to the center of the concave face, where more favorable hydrophobic interactions take over. Copyright © 2010 Elsevier Ltd. All rights reserved.

SEARCH FOR EXTRATERRESTRIAL ANTINEUTRINO SOURCES WITH THE KamLAND DETECTOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gando, A.; Gando, Y.; Ichimura, K.

2012-02-01

We present the results of a search for extraterrestrial electron antineutrinos ({nu}-bar{sub e}'s) in the energy range 8.3 MeV < E{sub {nu}}-bar{sub e} < 31.8 MeV using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of {sup 8}B solar {nu}{sub e}'s converting into {nu}-bar{sub e}'s at 5.3 Multiplication-Sign 10{sup -5} (90% CL), if we assume an undistorted {nu}-bar{sub e} shape. This limit corresponds to a solar {nu}-bar{sub e} flux ofmore » 93 cm{sup -2} s{sup -1} or an event rate of 1.6 events (kton - year){sup -1} above the energy threshold (E{sub {nu}}-bar{sub e}>=8.3 MeV). The present data also allows us to set more stringent limits on the diffuse supernova neutrino flux and on the annihilation rates for light dark matter particles.« less

Heavy-to-light scalar form factors from Muskhelishvili-Omnès dispersion relations

NASA Astrophysics Data System (ADS)

Yao, D.-L.; Fernandez-Soler, P.; Albaladejo, M.; Guo, F.-K.; Nieves, J.

2018-04-01

By solving the Muskhelishvili-Omnès integral equations, the scalar form factors of the semileptonic heavy meson decays D→ π \\bar{ℓ }ν _ℓ , D→ {\\bar{K}} \\bar{ℓ }ν _ℓ , {\\bar{B}}→ π ℓ \\bar{ν }_ℓ and {\\bar{B}}_s→ K ℓ \\bar{ν }_ℓ are simultaneously studied. As input, we employ unitarized heavy meson-Goldstone boson chiral coupled-channel amplitudes for the energy regions not far from thresholds, while, at high energies, adequate asymptotic conditions are imposed. The scalar form factors are expressed in terms of Omnès matrices multiplied by vector polynomials, which contain some undetermined dispersive subtraction constants. We make use of heavy quark and chiral symmetries to constrain these constants, which are fitted to lattice QCD results both in the charm and the bottom sectors, and in this latter sector to the light-cone sum rule predictions close to q^2=0 as well. We find a good simultaneous description of the scalar form factors for the four semileptonic decay reactions. From this combined fit, and taking advantage that scalar and vector form factors are equal at q^2=0, we obtain |V_{cd}|=0.244± 0.022, |V_{cs}|=0.945± 0.041 and |V_{ub}|=(4.3± 0.7)× 10^{-3} for the involved Cabibbo-Kobayashi-Maskawa (CKM) matrix elements. In addition, we predict the following vector form factors at q^2=0: |f_+^{D→ η }(0)|=0.01± 0.05, |f_+^{D_s→ K}(0)|=0.50 ± 0.08, |f_+^{D_s→ η }(0)|=0.73± 0.03 and |f_+^{{\\bar{B}}→ η }(0)|=0.82 ± 0.08, which might serve as alternatives to determine the CKM elements when experimental measurements of the corresponding differential decay rates become available. Finally, we predict the different form factors above the q^2-regions accessible in the semileptonic decays, up to moderate energies amenable to be described using the unitarized coupled-channel chiral approach.

Rayleigh-Brillouin light scattering spectroscopy of nitrous oxide (N2O)

NASA Astrophysics Data System (ADS)

Wang, Y.; Liang, K.; van de Water, W.; Marques, W.; Ubachs, W.

2018-02-01

High signal-to-noise and high-resolution light scattering spectra are measured for nitrous oxide (N2O) gas at an incident wavelength of 403.00 nm, at 90° scattering, at room temperature and at gas pressures in the range 0.5 - 4 bar. The resulting Rayleigh-Brillouin light scattering spectra are compared to a number of models describing in an approximate manner the collisional dynamics and energy transfer in this gaseous medium of this polyatomic molecular species. The Tenti-S6 model, based on macroscopic gas transport coefficients, reproduces the scattering profiles in the entire pressure range at less than 2% deviation at a similar level as does the alternative kinetic Grad's 6-moment model, which is based on the internal collisional relaxation as a decisive parameter. A hydrodynamic model fails to reproduce experimental spectra for the low pressures of 0.5-1 bar, but yields very good agreement ( < 1%) in the pressure range 2 - 4 bar. While these three models have a different physical basis the internal molecular relaxation derived can for all three be described in terms of a bulk viscosity of ηb ∼(6 ± 2) ×10-5 Pa · s. A 'rough-sphere' model, previously shown to be effective to describe light scattering in SF6 gas, is not found to be suitable, likely in view of the non-sphericity and asymmetry of the N-N-O structured linear polyatomic molecule.

Effects of Gravel Bars on Nutrient Spiraling in Bedrock-Alluvium Streams

NASA Astrophysics Data System (ADS)

Iobst, B. R.; Carroll, E. P.; Furbish, D. J.

2007-05-01

The importance of the connection between nutrient transport and local stream geomorphology is becoming increasingly important. Studies have shown that the interconnectivity of nutrient cycles in the downstream direction is in part controlled by the distribution and size of gravel bars in low order streams, as hyporheic flow occurs dominantly through alternate and mid-channel gravel bars. For this investigation multiple gravel bars in a 3rd order bedrock-alluvium stream were studied to determine general relationships between nutrient spiraling and hyporheic flow. The first goal was to understand (1) the extent to which water moves through hyporheic zones and (2) the basic chemistry of the hyporheic water. The second part of the study was to understand how nutrients, notably nitrogen, are affected in their cycling by the relatively long residence times encountered in gravel bars during hyporheic flow. Wells were installed along a 600 m reach of Panther Creek, KY in selected bars, as well as in a secondary location involving a grid installation pattern in one large bar. Results have shown that hyporheic flow through gravel bars is an important factor in influencing stream chemistry. Background water chemistry surveys have shown that certain parameters, specifically ammonium and nitrogen concentrations vary downstream, and that the dominant control over these changes is gravel bar location. Rhodamine WT was used in field tracer tests to track the travel times of water through bars as well as partitioning of water between the open channel and hyporheic flows. Further tests will be conducted utilizing a stable isotope study to determine how nitrogen is affected by hyporheic flow, and what implications this has for nutrient transport. We expect results to show that the spacing and size of gravel bars is a dominant control in key nutrient spiraling parameters, namely uptake lengths and overall nitrogen cycling rates. This has implications for how natural systems will respond to human impacts, both through the modification of the physical template of stream systems as well as increased anthropogenic loading of nitrogen.

A visual horizon affects steering responses during flight in fruit flies.

PubMed

Caballero, Jorge; Mazo, Chantell; Rodriguez-Pinto, Ivan; Theobald, Jamie C

2015-09-01

To navigate well through three-dimensional environments, animals must in some way gauge the distances to objects and features around them. Humans use a variety of visual cues to do this, but insects, with their small size and rigid eyes, are constrained to a more limited range of possible depth cues. For example, insects attend to relative image motion when they move, but cannot change the optical power of their eyes to estimate distance. On clear days, the horizon is one of the most salient visual features in nature, offering clues about orientation, altitude and, for humans, distance to objects. We set out to determine whether flying fruit flies treat moving features as farther off when they are near the horizon. Tethered flies respond strongly to moving images they perceive as close. We measured the strength of steering responses while independently varying the elevation of moving stimuli and the elevation of a virtual horizon. We found responses to vertical bars are increased by negative elevations of their bases relative to the horizon, closely correlated with the inverse of apparent distance. In other words, a bar that dips far below the horizon elicits a strong response, consistent with using the horizon as a depth cue. Wide-field motion also had an enhanced effect below the horizon, but this was only prevalent when flies were additionally motivated with hunger. These responses may help flies tune behaviors to nearby objects and features when they are too far off for motion parallax. © 2015. Published by The Company of Biologists Ltd.

Internal quantum efficiency and carrier dynamics in semipolar (2021) InGaN/GaN light-emitting diodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okur, Serdal; Nami, Mohsen; Rishinaramangalam, Ashwin K.

Here, the internal quantum efficiencies (IQE) and carrier lifetimes of semipolar (more » $$20\\bar{2}$$$\\bar{1}$$) InGaN/GaN LEDs with different active regions are measured using temperature-dependent, carrier-density-dependent, and time-resolved photoluminescence. Three active regions are investigated: one 12-nm-thick single quantum well (SQW), two 6-nm-thick QWs, and three 4-nm-thick QWs. The IQE is highest for the 12-nm-thick SQW and decreases as the well width decreases. The radiative lifetimes are similar for all structures, while the nonradiative lifetimes decrease as the well width decreases. The superior IQE and longer nonradiative lifetime of the SQW structure suggests using thick SQW active regions for high brightness semipolar ($$20\\bar{2}$$$\\bar{1}$$) LEDs.« less

Internal quantum efficiency and carrier dynamics in semipolar (2021) InGaN/GaN light-emitting diodes

DOE PAGES

Okur, Serdal; Nami, Mohsen; Rishinaramangalam, Ashwin K.; ...

2017-01-26

Here, the internal quantum efficiencies (IQE) and carrier lifetimes of semipolar (more » $$20\\bar{2}$$$\\bar{1}$$) InGaN/GaN LEDs with different active regions are measured using temperature-dependent, carrier-density-dependent, and time-resolved photoluminescence. Three active regions are investigated: one 12-nm-thick single quantum well (SQW), two 6-nm-thick QWs, and three 4-nm-thick QWs. The IQE is highest for the 12-nm-thick SQW and decreases as the well width decreases. The radiative lifetimes are similar for all structures, while the nonradiative lifetimes decrease as the well width decreases. The superior IQE and longer nonradiative lifetime of the SQW structure suggests using thick SQW active regions for high brightness semipolar ($$20\\bar{2}$$$\\bar{1}$$) LEDs.« less

Dispersion effects in the miscible displacement of two fluids in a duct of large aspect ratio

NASA Astrophysics Data System (ADS)

Zhang, J.; Frigaard, I. A.

We study miscible displacements in long ducts in the dispersive limit of small \\varepsilon Pe, where \\varepsilon ≪ 1 is the inverse aspect ratio and Pe the Péclet number. We consider the class of generalized Newtonian fluids, with specified closure laws for the fluid properties of the concentration-dependent mixture. Regardless of viscosity ratio and the constitutive laws of the pure fluids, for sufficiently small \\varepsilon Pe these displacements are characterized by rapid cross-stream diffusion and slow streamwise dispersion, i.e. the concentration appears to be near-uniform across the duct and spreads slowly as it translates. Using the multiple-scales method we derive the leading-order asymptotic approximation to the average fluid concentration bar{c}_0. We show that bar{c}_0 evolves on the slow timescale t ˜ (\\varepsilon Pe)^{-1}, and satisfies a nonlinear diffusion equation in a frame of reference moving with the mean speed of the flow. In the case that the two fluids have identical rheologies and the concentration represents a passive tracer, the diffusion equation is linear. For Newtonian fluids we recover the classical results of Taylor (l953), Aris (1956), and for power-law fluids those of Vartuli et al. (1995). In the case that the fluids differ and/or that mixing is non-passive, bar{c}_0 satisfies a nonlinear diffusion equation in the moving frame of reference. Given a specific mixing/closure law for the rheological properties, we are able to compute the dispersive diffusivity D_T(bar{c}_0) and predict spreading along the channel. We show that D_T(bar{c}_0) can vary significantly with choice of mixing law and discuss why. This also opens the door to possibilities of controlling streamwise spreading by the rheological design of reactive mixtures, i.e. including chemical additives such that the rheology of the mixture behaves very differently to the rheology of either pure fluid. Computed examples illustrate the potential effects that might be achieved.

Judder-Induced Edge Flicker at Zero Spatial Contrast

NASA Technical Reports Server (NTRS)

Larimer, James; Feng, Christine; Gille, Jennifer; Cheung, Victor

2004-01-01

Judder is a motion artifact that degrades the quality of video imagery. Smooth motion appears jerky and can appear to flicker along the leading and trailing edge of the moving object. In a previous paper, we demonstrated that the strength of the edge flicker signal depended upon the brightness of the scene and the contrast of the moving object relative to the background. Reducing the contrast between foreground and background reduced the flicker signal. In this report, we show that the contrast signal required for judder-induced edge flicker is due to temporal contrast and not simply to spatial contrast. Bars made of random dots of the same dot density as the background exhibit edge flicker when moved at sufficient rate.

The study of two barred galaxies with curious kinematical features

NASA Astrophysics Data System (ADS)

Saburova, A. S.; Katkov, I. Y.; Khoperskov, S. A.; Zasov, A. V.; Uklein, R. I.

2017-09-01

We performed long-slit spectral observations of two SB-type galaxies: NGC 5347 and UGC 1344. They were previously suspected as the galaxies with unusually low mass-to-light ratios (on the ground of mass estimates from the H I linewidths), which are in conflict with their observed colours. The observations were conducted at the Russian 6-m telescope. The aim of this study was to clarify the kinematics and structure, as well as the properties of stellar populations of the galaxies. The results of observations disproved the peculiarly low mass-to-light ratios of both galaxies. The most probable reasons of underestimation of their masses are discussed. We tried to reproduce the main observed features of kinematical profiles of the galaxies in the N-body simulations of barred galaxies. We found that both galaxies possess central components of different structures. Indeed, the age and velocity dispersion of stellar population in NGC 5347 are low in its innermost part in comparison to that of the bulge or a bar, which agrees with the presence of nuclear kinematically decoupled disc. It probably was formed due to the bar that supplied the inner region with gas. The kinematical profiles of the second galaxy UGC 1344 give evidence in favour of the central peanut-shaped bulge. In spite of the different luminosities of the two galaxies, they possess nearly equal (close to solar) central stellar abundance and the flattening of the stellar metallicity gradient in the bar regions. However, in the less luminous NGC 5347, the mean stellar age is younger than that in UGC 1344.

One leptoquark to unify them? Neutrino masses and unification in the light of (g - 2)μ, R D (⋆) and RK anomalies

NASA Astrophysics Data System (ADS)

Popov, Oleg; White, G. A.

2017-10-01

Leptoquarks have been proposed as a possible explanation of anomalies in B bar ↦D* τ ν bar decays, the apparent anomalies in (g - 2) μ experiments and a violation of lepton universality. Motivated by this, we examine other motivations of leptoquarks: radiatively induced neutrino masses in the presence of a discrete symmetry that prevents a tree level see-saw mechanism, gauge coupling unification, and vacuum stability at least up to the unification scale. We present a new model for radiatively generating a neutrino mass which can significantly improve gauge coupling unification at one loop. We discuss this, and other models in the light of recent work on flavour anomalies.

Simulating a slow bar in the low surface brightness galaxy UGC 628

NASA Astrophysics Data System (ADS)

Chequers, Matthew H.; Spekkens, Kristine; Widrow, Lawrence M.; Gilhuly, Colleen

2016-12-01

We present a disc-halo N-body model of the low surface brightness galaxy UGC 628, one of the few systems that harbours a `slow' bar with a ratio of corotation radius to bar length of R ≡ R_c/a_b ˜ 2. We select our initial conditions using SDSS DR10 photometry, a physically motivated radially variable mass-to-light ratio profile, and rotation curve data from the literature. A global bar instability grows in our submaximal disc model, and the disc morphology and dynamics agree broadly with the photometry and kinematics of UGC 628 at times between peak bar strength and the onset of buckling. Prior to bar formation, the disc and halo contribute roughly equally to the potential in the galaxy's inner region, giving the disc enough self-gravity for bar modes to grow. After bar formation, there is significant mass redistribution, creating a baryon-dominated inner and dark matter-dominated outer disc. This implies that, unlike most other low surface brightness galaxies, UGC 628 is not dark matter dominated everywhere. Our model nonetheless implies that UGC 628 falls on the same relationship between dark matter fraction and rotation velocity found for high surface brightness galaxies, and lends credence to the argument that the disc mass fraction measured at the location where its contribution to the potential peaks is not a reliable indicator of its dynamical importance at all radii.

Optical characterization of the oceanic unicellular cyanobacterium Synechococcus grown under a day-night cycle in natural irradiance

NASA Technical Reports Server (NTRS)

Stramski, Dariusz; Shalapyonok, Alexi; Reynolds, Rick A.

1995-01-01

The optical properties of the ocenanic cyanobacterium Synechococcus (clone WH8103) were examined in a nutrient-replete laboratory culture grown under a day-night cycle in natural irradiance. Measurements of the spectral absorption and beam attenuation coefficients, the size distribution of cells in suspension, and microscopic analysis of samples were made at intervals of 2-4 hours for 2 days. These measurements were used to calculate the optical properties at the level of a single 'mean' cell representative of the acutal population, specifically, the optical cross sections for spectral absorption bar-(sigma(sub a)), scattering bar-sigma(sub b))(lambda), and attentuation bar-(sigma(sub c))(lambda). In addition, concurrent determinations of chlorophyll a and particulate organic carbon allowed calculation of the Chl a- and C-specific optical coefficients. The refractive index of cells was derived from the observed data using a theory of light absorption and scattering by homogeneous spheres. Low irradiance because of cloudy skies resulted in slow division rates of cells in the culture. The percentage of dividing cells was unusually high (greater than 30%) throughout the experiment. The optical cross sections varied greatly over a day-night cycle, with a minimum near dawn or midmorning and maximum near dusk. During daylight hours, bar-(sigma(sub b)) and bar-(sigma(sub c)) can increase more than twofold and bar-(sigma(sub a) by as much as 45%. The real part of the refractive index n increaed during the day; changes in n had equal or greater effect than the varying size distribution on changes in bar-(sigma(sub c)) and bar-(sigma(sub b)). The contribution of changes in n to the increase of bar-(sigma(sub c))(660) during daylight hours was 65.7% and 45.1% on day 1 and 2, respectively. During the dark period, when bar-(sigma(sub c))(660) decreased by a factor of 2.9, the effect of decreasing n was dominant (86.3%). With the exception of a few hours during the second light period, the imaginary part of the refractive index n' showed little variation over a day-night cycle, and bar-(sigma(sub a)) was largely controlled by variations in cell size. The real part of the refractive index at lambda = 660 nm was correlated with the intracellular C concentration and the imaginary part at lambda = 678 nm with the intracellular Chl a concentration. The C-specfic attenuation coefficient showed significant diel variability, which has implications for the estimation of oceanic primary production from measurements of diel variability in beam attenuation. This study provides strong evidence that diel variability is an important component of the optical characterization of marine phytoplankton.

Northern Spotted Owl (Strix occidentalis caurina) Genome: Divergence with the Barred Owl (Strix varia) and Characterization of Light-Associated Genes

PubMed Central

Henderson, James B.; Wall, Jeffrey D.; Emerling, Christopher A.; Fuchs, Jérôme; Runckel, Charles; Mindell, David P.; Bowie, Rauri C. K.; DeRisi, Joseph L.; Dumbacher, John P.

2017-01-01

Abstract We report here the assembly of a northern spotted owl (Strix occidentalis caurina) genome. We generated Illumina paired-end sequence data at 90× coverage using nine libraries with insert lengths ranging from ∼250 to 9,600 nt and read lengths from 100 to 375 nt. The genome assembly is comprised of 8,108 scaffolds totaling 1.26 × 109 nt in length with an N50 length of 3.98 × 106 nt. We calculated the genome-wide fixation index (FST) of S. o. caurina with the closely related barred owl (Strix varia) as 0.819. We examined 19 genes that encode proteins with light-dependent functions in our genome assembly as well as in that of the barn owl (Tyto alba). We present genomic evidence for loss of three of these in S. o. caurina and four in T. alba. We suggest that most light-associated gene functions have been maintained in owls and their loss has not proceeded to the same extent as in other dim-light-adapted vertebrates. PMID:28992302

The Role of 2D Circulation in Sand Bar Migration

NASA Astrophysics Data System (ADS)

Splinter, K. D.; Holman, R. A.; Plant, N. G.; Holland, K. T.

2006-12-01

Models of bar dynamics typically involve moments of the cross-shore flow, with offshore movement associated with the strong offshore directed undertow and onshore migration related to wave asymmetry and skewness [Gallagher, et al., 1998]. Based on these hypotheses, models and laboratory studies have used the alongshore-mean bar position and alongshore-uniform wave conditions (a 1DH approach) to study bar response to varying wave conditions. Commonly, cases of offshore migration were reproduced with reasonable accuracy, but predictions of onshore migration were less successful. However, examination of time-exposure images of waves show that during periods of offshore migration, bars tend to be alongshore uniform and move rapidly offshore, but during onshore migration, sand bars are rarely straight, instead becoming very sinuous, violating the 1DH approach. We hypothesize that under milder wave conditions, the 2DH circulation associated with this alongshore-variable morphology is, in fact, largely responsible for increased onshore net sand transport and the resulting onshore bar movement. We extend the work of Plant et al. [in review] that relates bar position, sinuosity, and wave forcing within a dynamical feedback model. The model consists of coupled differential equations that govern the rates of change of cross-shore position and horizontal sinuosity as a function of the current cross-shore position and sinuosity and a proxy for wave forcing. Using a short data set from Duck, NC, they solve for the unknown coupling coefficients by doing a least-squares fit. They find that the coefficients for the self-interaction terms have a negative sign, indicating the overall system is stable. The coefficients of the cross-interaction terms (the effect of sinuosity on rate of change of bar position and visa versa), however, are non-zero and have opposite signs indicating the systems are coupled and stability is not affected by these terms. We expand this study, relating bar position, sinuosity, and incident wave conditions, over a one-year period of time-exposure images of Palm Beach, Australia. The resulting analysis produces clear links between bar sinuosity and the rate of change of mean bar position, suggesting a 2DH approach should be used when modeling bar migration. Gallagher, E. L., et al. (1998), Observations of sand bar evolution on a natural beach, Journal of Geophysical Research, 103, 3203-3215. Plant, N. G., et al. (in review), A dynamical attractor governs beach response to storms, Journal of Geophysical Research.

[Dynamics of tuning to orientation of cross-like figures in neurons from the cat visual cortex].

PubMed

Lazareva, N A; Tsutskiridze, D Iu; Shevelev, I A; Novikova, R V; Tikhomirov, A S; Sharaev, G A

2003-01-01

Dynamics of tuning to orientation of flashing light bar and to orientation of cross-like figure was studied by a temporal slices method in 87 neurons of the cat primary visual cortex. Tuning was plotted by spikes number in the entire response and in its successive fragments with a step of 20 ms. It was found that successive dynamic shift of preferred orientation of a bar was typical for 87% units, white such shift of preferred orientation of a cross was met in 75% of cases. Comparison of tuning dynamics for bar and cross allowed to separate units into three groups: the first one (58.6% of cases) with larger dynamic shift of a bar preferred orientation then of a cross (74.9 +/- 5.8 degrees [symbol: see text] 29.8 +/- 4.1 degrees, correspondingly, p < 0.00001), the second group (21.5%) with opposite effect (24.2 +/- 5.2 degrees and 69.2 +/- 10.0 degrees, p < 0.0002) and the third group (19.8%) without significant shift of preferred orientation of bar and cross and without difference in their dynamics. Possible mechanisms of the preferred orientation dynamics and its difference for bar and cross are discussed.

[Amaranth bars enriched with fructans: acceptability and nutritional value].

PubMed

Dias Capriles, Vanessa; Gomes Arêas, José Alfredo

2010-09-01

There is an increasing appeal for convenience foods with potential health benefits to the consumer. Raw materials with high nutritional value and functional properties must be used on the development of these food products. Amaranth is a gluten-free grain with high nutrition value. Inulin and oligofructose are prebiotic ingredients presenting effects as the enhancement of calcium absorption. Amaranth bars enriched with inulin and oligofructose were developed in the flavors: banana, Brazilian nuts and dried grape, coconut, peach, strawberry and wall nut. The proximate composition were determined and compared to commercial cereal bars, available in traditional (n=59), light (n=60), diet (n=8), with soy (n=10) and quinoa (n=1) categories. Amaranth bars present mean global acceptance values from 6.3 to 7.6 on a 9-point hedonic scale, nutritional advantages as compared to commercial cereal bars (caloric reduction and higher levels of dietary fiber). Although amaranth is an unknown raw material in Brazil, it shows good potential to be used in the manufacturing of ready-to-eat products. As they are gluten free, these amaranth bars are also an alternative product for celiacs, also contributing to the enhancement of calcium absorption, a problem frequently observed in these patients.

"At Sea": Reversibility in Teaching and Learning

ERIC Educational Resources Information Center

Cavicchi, Elizabeth Mary

2018-01-01

An equal-armed balance at equilibrium--the bar is horizontal--tips into disequilibrium upon displacing a weight. Equilibrium is restored by reversing that move--putting the weight back where it was, or doing the same on the other side. Piaget adopted the idea of equilibration to describe how the intellect, in relating to the world, develops.…

Photosynthetic Energy Transduction | Bioenergy | NREL

Science.gov Websites

a large lighter green oval. There is a black line moving from one green bar to the other indicating blue oval labeled "FDX" and one green arrow pointing into the oval, labeled "electrons images with the third red line connecting the top of one L-shape to the bottom of the next L-shape

36 CFR 1192.107 - Restrooms.

Code of Federal Regulations, 2012 CFR

2012-07-01

... shelves may overlap the clear floor space at a lower height provided they can be easily folded up or moved... of the toilet seat. Seats shall not be sprung to return to a lifted position. (3) A grab bar at least... mobility aids and shall be connected to such a space by an unobstructed path having a minimum width of 32...

36 CFR § 1192.107 - Restrooms.

Code of Federal Regulations, 2013 CFR

2013-07-01

... shelves may overlap the clear floor space at a lower height provided they can be easily folded up or moved... of the toilet seat. Seats shall not be sprung to return to a lifted position. (3) A grab bar at least... mobility aids and shall be connected to such a space by an unobstructed path having a minimum width of 32...

36 CFR 1192.107 - Restrooms.

Code of Federal Regulations, 2014 CFR

2014-07-01

... shelves may overlap the clear floor space at a lower height provided they can be easily folded up or moved... of the toilet seat. Seats shall not be sprung to return to a lifted position. (3) A grab bar at least... mobility aids and shall be connected to such a space by an unobstructed path having a minimum width of 32...

Anxiety and Uncertainty in Aesthetic Education

ERIC Educational Resources Information Center

Schiralli, Martin

2002-01-01

In choosing a title for what might well be his least successful long poem, W. H. Auden nonetheless succeeded brilliantly in the far more ambitious task of naming an age. Set in his version of the urban Waste Land, a New York bar, "The Age of Anxiety" probes the dislocations of the modern consciousness as its four principal characters move uneasily…

Deriving the pattern speed using dynamical modelling of gas flows in barred galaxies .

NASA Astrophysics Data System (ADS)

Pérez, I.; Freeman, K. C.; Fux, R.; Zurita, A.

In this paper we analyse the methodology to derive the bar pattern speed from dynamical simulations. The results are robust to the changes in the vertical-scale height and in the mass-to-light (M/L) ratios. There is a small range of parameters for which the kinematics can be fitted. We have also taken into account the use of different type of dynamical modelling and the effect of using 2-D vs 1-D models in deriving the pattern speeds. We conclude that the derivation of the bar streaming motions and strength and position of shocks is not greatly affected by the fluid dynamical model used. We show new results on the derivation of the pattern speed for NGC 1530. The best fit pattern speed is around 10 km s-1 kpc-1 , which corresponds to a R_cor/R_bar = 1.4, implying a slower bar than previously derived from more indirect assumptions. With this pattern speed, the global and most local kinematic features are beautifully reproduced. However, the simulations fail to reproduce the velocity gradients close to some bright HII regions in the bar. We have shown from the study of the H{alpha } equivalent widths that the HII regions that are located further away from the bar dust-lane in its leading side, downstream from the main bar dust-lane, are older than the rest by 1.5-2.5 Myr. In addition, a clear spatial correlation was found between the location of HII regions, dust spurs on the trailing side of the bar dust-lane, and the loci of maximum velocity gradients parallel to the bar major axis.

Cherenkov radiation of superluminal particles

NASA Astrophysics Data System (ADS)

Rohrlich, Daniel; Aharonov, Yakir

2002-10-01

Any charged particle moving faster than light through a medium emits Cherenkov radiation. We show that charged particles moving faster than light through the vacuum emit Cherenkov radiation. How can a particle move faster than light? The weak speed of a charged particle can exceed the speed of light. By definition, the weak velocity w is <Ψfin|v|Ψin>/<Ψfin|Ψin>, where v is the velocity operator and |Ψin> and |Ψfin> are, respectively, the states of a particle before and after a velocity measurement. We discuss the consistency of weak values and show that superluminal weak speed is consistent with relativistic causality.

Light quark Yukawa couplings from Higgs kinematics

DOE PAGES

Soreq, Yotam; Zhu, Hua Xing; Zupan, Jure

2016-12-13

We show that the normalized Higgs production p T and y h distributions are sensitive probes of Higgs couplings to light quarks. For up and/or down quark Yukawa couplings comparable to the SM b quark Yukawa themore » $$\\bar{u}u$$ or $$\\bar{d}d$$ fusion production of the Higgs could lead to appreciable softer p T distribution than in the SM. The rapidity distribution, on the other hand, becomes more forward. Here, we find that, owing partially to a downward fluctuation, one can derive competitive bounds on the two couplings using ATLAS measurements of normalized p T distribution at 8TeV. With 300 fb -1 at 13TeV LHC one could establish flavor non-universality of the Yukawa couplings in the down sector.« less

Palateless custom bar supported overdenture: a treatment modality to treat patient with severe gag reflex.

PubMed

Singh, Kunwarjeet; Gupta, Nidhi

2012-01-01

To suggest a custom bar supported overdenture treatment modality for prosthodontic management of patients with severe gag reflex. Some patients have a severe gag reflex and cannot tolerate conventional maxillary complete dentures with maximum palatal coverage and extensions of all borders. The condition further gets complicated in patients suffering from respiratory problems along with severe gag reflex. Severe gagging acts as a barrier to treat such patients with accepted clinical procedures and prevent patients from wearing the prosthesis. By saving some of the remaining natural teeth and fabricating, a horse shoe shape palateless simple tooth or bar supported overdenture can be successfully used for treating such patients. The remaining maxillary right and left canines were prepared with the tapered round end diamond bur to receive copings of custom bar after intentional root canal treatment of same teeth. Impression was made with light body and putty of the polyvinyl siloxane elastomer with double step putty wash technique. Impression was poured with die stone. Wax pattern of copings with bar was fabricated with inlay wax which was invested and casted. After retrieving the bar, it was finished and its fit was evaluated. The coping-bar assembly was finally cemented with the glass ionomer cement. Palateless overdenture was fabricated by conventional technique used for the fabrication of complete denture. Palateless custom bar supported overdenture procedure can be successfully used for the management of patients with severe gag reflex with improved denture retention, stability, chewing efficiency and comfort of the patient.

Mass spectra and decay properties of the c\\bar{c} meson

NASA Astrophysics Data System (ADS)

Chaturvedi, Raghav; Kumar Rai, Ajay

2018-06-01

In this article we present the result of c\\bar{c} meson mass calculation by solving the Schrödinger equation numerically considering the Coulomb plus linear potential. The spin-hyperfine, spin-orbit and tensor components of one-gluon-exchange interactions are employed to obtain the mass spectra of c\\bar{c} meson. The calculated mass spectra are compared with the latest results of PDG and are found to be in good accordance. The Regge trajectories of the calculated mass spectra have also been constructed. The values of the wave function are extracted and employed to calculate the leptonic decay constant, γγ, gg, e+e-, light hadron (LH) and γγγ decay widths of S-wave 0^{-+} and 1^{- -} states of c\\bar{c} meson, the widths have been calculated by Van Royen-Weisskopf formula and by NRQCD mechanism incorporating relativistic corrections of order ν2. The γγ and gg decay widths of χ0 and χ2 states of c\\bar{c} meson have also been calculated. The calculated decay constants and widths have been compared with the experimental results.

NASA Tech Briefs, May 2005

NASA Technical Reports Server (NTRS)

2005-01-01

Topics covered include: Fastener Starter; Multifunctional Deployment Hinges Rigidified by Ultraviolet; Temperature-Controlled Clamping and Releasing Mechanism; Long-Range Emergency Preemption of Traffic Lights; High-Efficiency Microwave Power Amplifier; Improvements of ModalMax High-Fidelity Piezoelectric Audio Device; Alumina or Semiconductor Ribbon Waveguides at 30 to 1,000 GHz; HEMT Frequency Doubler with Output at 300 GHz; Single-Chip FPGA Azimuth Pre-Filter for SAR; Autonomous Navigation by a Mobile Robot; Software Would Largely Automate Design of Kalman Filter; Predicting Flows of Rarefied Gases; Centralized Planning for Multiple Exploratory Robots; Electronic Router; Piezo-Operated Shutter Mechanism Moves 1.5 cm; Two SMA-Actuated Miniature Mechanisms; Vortobots; Ultrasonic/Sonic Jackhammer; Removing Pathogens Using Nano-Ceramic-Fiber Filters; Satellite-Derived Management Zones; Digital Equivalent Data System for XRF Labeling of Objects; Identifying Objects via Encased X-Ray-Fluorescent Materials - the Bar Code Inside; Vacuum Attachment for XRF Scanner; Simultaneous Conoscopic Holography and Raman Spectroscopy; Adding GaAs Monolayers to InAs Quantum-Dot Lasers on (001) InP; Vibrating Optical Fibers to Make Laser Speckle Disappear; Adaptive Filtering Using Recurrent Neural Networks; and Applying Standard Interfaces to a Process-Control Language.

Variation and decomposition of the partial molar volume of small gas molecules in different organic solvents derived from molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Klähn, Marco; Martin, Alistair; Cheong, Daniel W.; Garland, Marc V.

2013-12-01

The partial molar volumes, bar V_i, of the gas solutes H2, CO, and CO2, solvated in acetone, methanol, heptane, and diethylether are determined computationally in the limit of infinite dilution and standard conditions. Solutions are described with molecular dynamics simulations in combination with the OPLS-aa force field for solvents and customized force field for solutes. bar V_i is determined with the direct method, while the composition of bar V_i is studied with Kirkwood-Buff integrals (KBIs). Subsequently, the amount of unoccupied space and size of pre-formed cavities in pure solvents is determined. Additionally, the shape of individual solvent cages is analyzed. Calculated bar V_i deviate only 3.4 cm3 mol-1 (7.1%) from experimental literature values. Experimental bar V_i variations across solutions are reproduced qualitatively and also quantitatively in most cases. The KBI analysis identifies differences in solute induced solvent reorganization in the immediate vicinity of H2 (<0.7 nm) and solvent reorganization up to the third solvation shell of CO and CO2 (<1.6 nm) as the origin of bar V_i variations. In all solutions, larger bar V_i are found in solvents that exhibit weak internal interactions, low cohesive energy density and large compressibility. Weak internal interactions facilitate solvent displacement by thermal solute movement, which enhances the size of solvent cages and thus bar V_i. Additionally, attractive electrostatic interactions of CO2 and the solvents, which do not depend on internal solvent interactions only, partially reversed the bar V_i trends observed in H2 and CO solutions where electrostatic interactions with the solvents are absent. More empty space and larger pre-formed cavities are found in solvents with weak internal interactions, however, no evidence is found that solutes in any considered solvent are accommodated in pre-formed cavities. Individual solvent cages are found to be elongated in the negative direction of solute movement. This wake behind the moving solute is more pronounced in case of mobile H2 and in solvents with weaker internal interactions. However, deviations from a spherical solvent cage shape do not influence solute-solvent radial distribution functions after averaging over all solvent cage orientations and hence do not change bar V_i. Overall, the applied methodology reproduces bar V_i and its variations reliably and the used bar V_i decompositions identify the underlying reasons behind observed bar V_i variations.

33 CFR 110.55 - Connecticut River, Conn.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Vicinity of Mouse Island Bar below Portland. On the north side of the river shoreward of lines described as follows: (1) Beginning at a point bearing 02°, 175 yards, from Mouse Island 73 Light; thence 270°, 480... bearing 02°, 175 yards, from Mouse Island 73 Light; thence 70°, 400 yards; and thence 350°, approximately...

33 CFR 110.55 - Connecticut River, Conn.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Vicinity of Mouse Island Bar below Portland. On the north side of the river shoreward of lines described as follows: (1) Beginning at a point bearing 02°, 175 yards, from Mouse Island 73 Light; thence 270°, 480... bearing 02°, 175 yards, from Mouse Island 73 Light; thence 70°, 400 yards; and thence 350°, approximately...

Vaccines Stop Illness

MedlinePlus

Skip Navigation Bar Home Current Issue Past Issues Vaccines Stop Illness Past Issues / Spring 2008 Table of ... meningitis won't infect, cripple, or kill children. Vaccine Safety In light of recent questions about vaccine ...

Tool setting device

DOEpatents

Brown, Raymond J.

1977-01-01

The present invention relates to a tool setting device for use with numerically controlled machine tools, such as lathes and milling machines. A reference position of the machine tool relative to the workpiece along both the X and Y axes is utilized by the control circuit for driving the tool through its program. This reference position is determined for both axes by displacing a single linear variable displacement transducer (LVDT) with the machine tool through a T-shaped pivotal bar. The use of the T-shaped bar allows the cutting tool to be moved sequentially in the X or Y direction for indicating the actual position of the machine tool relative to the predetermined desired position in the numerical control circuit by using a single LVDT.

An electron microscopy examination of primary recrystallization in TD-nickel.

NASA Technical Reports Server (NTRS)

Petrovic, J. J.; Ebert, L. J.

1972-01-01

Primary recrystallization in TD-nickel 1 in. bar has previously been regarded as the process by which the initial fine grain structure is converted to a coarse grain size (increases in grain size by 500 times) under suitable deformation and annealing conditions. This process is dependent on deformation mode. While it occurs readily after rolling transverse to the bar axis and annealing (800 C), it is completely inhibited by longitudinal rolling and swaging deformations, even for very high (1320 C) annealing temperatures. A transmission electron microscopy examination of deformation and annealing substructures indicates that primary recrystallization in TD-nickel 1 in. bar actually occurs on the sub-light optical level, to produce a grain structure similar in size to the initial fine grained state.

Image decomposition of barred galaxies and AGN hosts

NASA Astrophysics Data System (ADS)

Gadotti, Dimitri Alexei

2008-02-01

I present the results of multicomponent decomposition of V and R broad-band images of a sample of 17 nearby galaxies, most of them hosting bars and active galactic nuclei (AGN). I use BUDDA v2.1 to produce the fits, allowing the inclusion of bars and AGN in the models. A comparison with previous results from the literature shows a fairly good agreement. It is found that the axial ratio of bars, as measured from ellipse fits, can be severely underestimated if the galaxy axisymmetric component is relatively luminous. Thus, reliable bar axial ratios can only be determined by taking into account the contributions of bulge and disc to the light distribution in the galaxy image. Through a number of tests, I show that neglecting bars when modelling barred galaxies can result in an overestimation of the bulge-to-total luminosity ratio of a factor of 2. Similar effects result when bright, type 1 AGN are not considered in the models. By artificially redshifting the images, I show that the structural parameters of more distant galaxies can in general be reliably retrieved through image fitting, at least up to the point where the physical spatial resolution is ~1.5kpc. This corresponds, for instance, to images of galaxies at z = 0.05 with a seeing full width at half-maximum (FWHM) of 1.5arcsec, typical of the Sloan Digital Sky Survey (SDSS). In addition, such a resolution is also similar to what can be achieved with the Hubble Space Telescope (HST), and ground-based telescopes with adaptive optics, at z ~ 1-2. Thus, these results also concern deeper studies such as COSMOS and SINS. This exercise shows that disc parameters are particularly robust, but bulge parameters are prone to errors if its effective radius is small compared to the seeing radius, and might suffer from systematic effects. For instance, the bulge-to-total luminosity ratio is systematically overestimated, on average, by 0.05 (i.e. 5 per cent of the galaxy total luminosity). In this low-resolution regime, the effects of ignoring bars are still present, but AGN light is smeared out. I briefly discuss the consequences of these results to studies of the structural properties of galaxies, in particular on the stellar mass budget in the local Universe. With reasonable assumptions, it is possible to show that the stellar content in bars can be similar to that in classical bulges and elliptical galaxies. Finally, I revisit the cases of NGC4608 and 5701 and show that the lack of stars in the disc region inside the bar radius is significant. Accordingly, the best-fitting model for the former uses a Freeman type II disc.

NGC 1291

NASA Image and Video Library

2007-11-14

This image from NASA Galaxy Evolution Explorer shows the galaxy NGC 1291, located about 33 million light-years away in the constellation Eridanus. NGC 1291 is notable for its unusual inner bar and outer ring structure.

Cure width potential for MOD resin composite molar restorations.

PubMed

Palin, William M; Senyilmaz, Dilek P; Marquis, Peter M; Shortall, Adrian C

2008-08-01

To investigate the capability of modern light-curing units exhibiting differences in emission spectra and light source exit window dimensions, for "one-shot" full-width curing of extensive (molar MOD) resin composite restorations. Specimens of Tetric (TT), Tetric Ceram HB (TC), Tetric Evoceram (TE) and Tetric Ceram Bleach (TB) resin composites containing varying ratios of Lucirin (TPO) and/or camphorquinone (CQ) photoinitiators were packed into a bar-shaped mould (12 mm length x 2 mm width x 2 mm thickness). Each product was irradiated using a halogen (Optilux 401; QTH), a conventional LED (LEDemetron; LED) and two so-called "third generation" oval-footprint LED light-curing units (LCUs) of the same model. The latter featured bimodal emission spectra (blue and ultraviolet diodes) with either high (unmodified output) and approximately 50% (modified output) blue light intensity (UltraLume-5; ULs, ULm, respectively). Vickers hardness number was obtained across the lateral extent of the bar at 1mm increments from the centre point on both upper and lower surfaces of the specimens. Significant linear relationships (R(2)=0.71-0.98) for each distance from the central position of all LCUs were identified between measured light intensity and corresponding upper and lower surface hardness values for each product (P<0.05). No significant differences (P>0.05) were recorded in total upper surface hardness of TC or TE cured with LED (68.7+/-3.2 and 70.5+/-2.5) or ULm (56.8+/-2.0 and 57.7+/-2.0). However, upper surface hardness of TT (CQ only) cured with ULm was significantly decreased (P<0.05) compared with other LCUs. When the ratio of hardness at the edge to central positions of the bar-shaped specimens for either surface was calculated, no significant difference (P>0.05) was identified for TB (containing TPO and decreased CQ) cured with either ULs or ULm (P>0.05) and was significantly increased (P<0.05) when cured with ULs compared with LED and QTH. Variability in light intensity across the curing-tip face, spectral output of dental light-curing units and differences in product photoinitiator chemistry all influence curing efficiency significantly across the width of extensive resin composite geometries.

18. Photocopy of photograph. VIEW WITHIN POSTMORTEM CELL OF MANIPULATOR ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. Photocopy of photograph. VIEW WITHIN POST-MORTEM CELL OF MANIPULATOR ARMS BEING USED TO MOVE METAL BARS FROM ONE LOCATION TO ANOTHER. Photographer unknown, ca. 1965, original photograph and negative on file at the Remote Sensing Laboratory, Department of Energy, Nevada Operations Office. - Nevada Test Site, Engine Maintenance Assembly & Disassembly Facility, Area 25, Jackass Flats, Mercury, Nye County, NV

Moving beyond the Bar Plot and the Line Graph to Create Informative and Attractive Graphics

ERIC Educational Resources Information Center

Larson-Hall, Jenifer

2017-01-01

Graphics are often mistaken for a mere frill in the methodological arsenal of data analysis when in fact they can be one of the simplest and at the same time most powerful methods of communicating statistical information (Tufte, 2001). The first section of the article argues for the statistical necessity of graphs, echoing and amplifying similar…

Wyoming Community College Commission Agency 5 Year Strategic Plan, 2015-2019

ERIC Educational Resources Information Center

Wyoming Community College Commission, 2017

2017-01-01

In 2009, the Wyoming Community College Commission was tasked to create a blue-ribbon panel that would forge a Strategic Plan for the Community College System as a whole. This 5 year strategic plan will serve as a road map moving forward, barring any new legislative, commission or federal requirements that may require a change in the agency's…

Wyoming Community College Commission Agency 5 Year Strategic Plan, 2014-2018

ERIC Educational Resources Information Center

Wyoming Community College Commission, 2017

2017-01-01

In 2009, the Wyoming Community College Commission was tasked to create a blue-ribbon panel that would forge a Strategic Plan for the Community College System as a whole. This 5 year strategic plan will serve as a road map moving forward, barring any new legislative, commission or federal requirements that may require a change in the agency's…

Transport in the barrier billiard

NASA Astrophysics Data System (ADS)

Saberi Fathi, S. M.; Ettoumi, W.; Courbage, M.

2016-06-01

We investigate transport properties of an ensemble of particles moving inside an infinite periodic horizontal planar barrier billiard. A particle moves among bars and elastically reflects on them. The motion is a uniform translation along the bars' axis. When the tangent of the incidence angle, α , is fixed and rational, the second moment of the displacement along the orthogonal axis at time n , , is either bounded or asymptotic to K n2 , when n →∞ . For irrational α , the collision map is ergodic and has a family of weakly mixing observables, the transport is not ballistic, and autocorrelation functions decay only in time average, but may not decay for a family of irrational α 's. An exhaustive numerical computation shows that the transport may be superdiffusive or subdiffusive with various rates or bounded strongly depending on the values of α . The variety of transport behaviors sounds reminiscent of well-known behavior of conservative systems. Considering then an ensemble of particles with nonfixed α , the system is nonergodic and certainly not mixing and has anomalous diffusion with self-similar space-time properties. However, we verified that such a system decomposes into ergodic subdynamics breaking self-similarity.

Fabry-Perot sensors for the monitoring of FRP reinforced bridge decks

NASA Astrophysics Data System (ADS)

Benmokrane, Brahim; Quirion, Marco; El-Salakawy, Ehab; Debaiky, Ahmed S.; Lackey, Tom

2004-07-01

The extensive use of deicing salts in Canada during winter times is identified as the main reason behind the deterioration of highway bridges and parking garages. To fight this infrastructure crisis, Fibre Reinforced Polymers (FRP) has become a very attractive alternative to traditional reinforcing steel due to their non-corrosive nature and light weight. The replacement of steel with Glass FRP bars in bridge deck slabs has been extensively researched in the last few years. This paper presents the first efforts to implement these bars in two highway bridges in Quebec, Canada, and Vermont, USA. These projects are aimed to prove the feasibility of using GFRP bars in bridge construction. GFRP bars were used as reinforcement for parts of the deck slabs in the two bridges while traditional steel was used in the remaining parts. Fibre Optic Sensors (FOS) were used to measure strains in the concrete, reinforcing bars and steel girders. The sensors were surface mounted on the bars or steel girders using standard glue, or embedded in concrete. Static and dynamic testing of the bridges was done using loaded trucks placed for maximum stresses. The design, construction, testing, and results obtained from the bridges are briefly outlined in this paper. The results indicated the accuracy of the sensors and their feasibility for bridge construction and remote monitoring.

Linking human impacts within an estuary to ebb-tidal delta evolution

USGS Publications Warehouse

Dallas, Kate L.; Barnard, Patrick L.

2009-01-01

San Francisco Bay, California, USA is among the most anthropogenically altered estuaries in the entire United States, but the impact on sediment transport to the coastal ocean has not been quantified. Analysis of four historic bathymetric surveys has revealed large changes to the morphology of the San Francisco Bar, an ebb-tidal delta at the mouth of the San Francisco Bay. From 1873 to 2005 the bar eroded an average of 80 cm, which equates to a total volume loss of 100 + 65 x 106 m3 of sediment. Comparison of the surveys indicates the entire ebb delta has contracted radially while its crest has moved landward an average of 1 km. Compilation of historic records reveals that 130 x 106 m3 of sediment has been permanently removed from the San Francisco Bay and adjacent coastal ocean. Constriction of the bar is hypothesized to be from a decrease in sediment supply from San Francisco Bay, a reduction in the tidal prism of the estuary, and/or a reduction in the input of hydraulic mining debris. Changes to the morphology of the San Francisco Bar have likely altered wave refraction and focusing patterns on adjacent beaches and may be a factor in persistent beach erosion occurring in the area.

A light for anaesthetists.

PubMed

Flowerdew, R M

1976-11-01

A new type of lighting device is incorporated into the ether screen cross-bar, enabling better illumination of the patient's face. A 12-V, DC power supply is used. The temperature, with vacuum-assisted cooling, should not cause burns to an unconscious patient. Assessment of patient colour was evaluated and found to be reliable. The lamp must not be used with flammable anaesthetic agents.

Northern Spotted Owl (Strix occidentalis caurina) Genome: Divergence with the Barred Owl (Strix varia) and Characterization of Light-Associated Genes.

PubMed

Hanna, Zachary R; Henderson, James B; Wall, Jeffrey D; Emerling, Christopher A; Fuchs, Jérôme; Runckel, Charles; Mindell, David P; Bowie, Rauri C K; DeRisi, Joseph L; Dumbacher, John P

2017-10-01

We report here the assembly of a northern spotted owl (Strix occidentalis caurina) genome. We generated Illumina paired-end sequence data at 90× coverage using nine libraries with insert lengths ranging from ∼250 to 9,600 nt and read lengths from 100 to 375 nt. The genome assembly is comprised of 8,108 scaffolds totaling 1.26 × 109 nt in length with an N50 length of 3.98 × 106 nt. We calculated the genome-wide fixation index (FST) of S. o. caurina with the closely related barred owl (Strix varia) as 0.819. We examined 19 genes that encode proteins with light-dependent functions in our genome assembly as well as in that of the barn owl (Tyto alba). We present genomic evidence for loss of three of these in S. o. caurina and four in T. alba. We suggest that most light-associated gene functions have been maintained in owls and their loss has not proceeded to the same extent as in other dim-light-adapted vertebrates. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Elegant spiral hides a hungry monster

NASA Image and Video Library

2015-10-12

NGC 4639 is a beautiful example of a type of galaxy known as a barred spiral. It lies over 70 million light-years away in the constellation of Virgo and is one of about 1500 galaxies that make up the Virgo Cluster. In this image, taken by the NASA/ESA Hubble Space Telescope, one can clearly see the bar running through the bright, round core of the galaxy. Bars are found in around two thirds of spiral galaxies, and are thought to be a natural phase in their evolution. The galaxy’s spiral arms are sprinkled with bright regions of active star formation. Each of these tiny jewels is actually several hundred light-years across and contains hundreds or thousands of newly formed stars. But NGC 4639 also conceals a dark secret in its core — a massive black hole that is consuming the surrounding gas. This is known as an active galactic nucleus (AGN), and is revealed by characteristic features in the spectrum of light from the galaxy and by X-rays produced close to the black hole as the hot gas plunges towards it. Most galaxies are thought to contain a black hole at the centre. NGC 4639 is in fact a very weak example of an AGN, demonstrating that AGNs exist over a large range of activity, from galaxies like NGC 4639 to distant quasars, where the parent galaxy is almost completely dominated by the emissions from the AGN.

Two new species of Melanorivulus (Cyprinodontiformes: Cynolebiidae) from Rio Verde drainage, Upper Rio Paraná basin, Brazil.

PubMed

Volcan, Matheus Vieira; Klotzel, Bruno; Lanés, Luis Esteban Krause

2017-02-21

Two new species of the genus Melanorivulus are herein described from the middle Rio Verde drainage, upper Rio Paraná basin, Mato Grosso do Sul, Brazil. Both new species are members of the Melanorivulus pictus clade, diagnosed by having ventral process of angulo-articular vestigial and flanks intense greenish blue or greenish golden to purplish blue above anal fin base in males. Melanorivulus nigropunctatus, new species, from wetlands of a small drainage tributary of right side of the Rio Verde, differs from all other congeners by possessing black dots over the head and body in both sexes and pectoral fin orange with a dark grey margin in males. Melanorivulus ofaie, new species, is found in a similar environment, but at the opposite margin of the Rio Verde. It is distinguished by males presenting flank greenish blue to light blue, with seven to nine oblique chevron-like red bars, ventral portion of head whitish with dark brown spots, dorsal fin yellow with two to three transverse broad red oblique stripes and distal region red, anal fin light orangish yellow, basal area light blue with short red bars and distal portion with a dark red margin, and caudal fin yellow or orangish yellow with three to four vertical red bars in the dorsal and middle portions, sometimes with a orange distal margin. Both new species are considered endangered due to the loss and degradation of their habitat.

Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation.

PubMed

Lawrence, Michael A; Leib, Daniel J; Ostrowski, Stephanie J; Carlson, Lara A

2017-05-01

Lawrence, MA, Leib, DJ, Ostrowski, SJ, and Carlson, LA. Nonlinear analysis of an unstable bench press bar path and muscle activation. J Strength Cond Res 31(5): 1206-1211, 2017-Unstable resistance exercises are typically performed to improve the ability of stabilizing muscles to maintain joint integrity under a load. The purpose of this study was to examine the effects of an unstable load (as provided by a flexible barbell and a load suspended by elastic bands) on the bar path, the primary musculature, and stabilizing musculature while bench pressing using nonlinear analyses. Fifteen resistance-trained men (age 24.2 ± 2.7 years, mass 84.1 ± 12.0 kg, height 1.77 ± 0.05 m, 9.9 ± 3.4 years of lifting experience, and bench press 1 repetition maximum (RM) 107.5 ± 25.9 kg) volunteered for this study. Subjects pressed 2 sets of 5 repetitions in both stable (total load 75% 1RM) and unstable (total load 60% 1RM) conditions using a standard barbell and a flexible Earthquake bar, respectively. Surface electromyography was used to detect muscle activity of primary movers (pectoralis major, anterior deltoid, and triceps) and bar stabilizing musculature (latissimus dorsi, middle and posterior deltoid, biceps brachii, and upper trapezius). During the unstable condition, the bar moved in more ways and was less predictable in the mediolateral and anteroposterior directions. However, the muscle activation patterns of all muscles were more constrained with the unstable barbell. These findings suggest that the unstable condition was more challenging to control, but subjects controlled the instability by contracting their muscles in a more stable pattern or "staying tight" throughout the exercise.

The Observation of the Structure of M23C6/ γ Coherent Interface in the 100Mn13 High Carbon High Manganese Steel

NASA Astrophysics Data System (ADS)

Xu, Zhenfeng; Ding, Zhimin; Liang, Bo

2018-03-01

The M23C6 carbides precipitate along the austenite grain boundary in the 100Mn13 high carbon high manganese steel after 1323 K (1050 °C) solution treatment and subsequent 748 K (475 °C) aging treatment. The grain boundary M23C6 carbides not only spread along the grain boundary and into the incoherent austenite grain, but also grow slowly into the coherent austenite grain. On the basis of the research with optical microscope, a further investigation for the M23C6/ γ coherent interface was carried out by transmission electron microscope (TEM). The results show that the grain boundary M23C6 carbides have orientation relationships with only one of the adjacent austenite grains in the same planes: (\\bar{1}1\\bar{1})_{{{M}_{ 2 3} {C}_{ 6} }} //(\\bar{1}1\\bar{1})_{γ } , (\\bar{1}11)_{{{M}_{ 2 3} {C}_{ 6} }} //(\\bar{1}11)_{γ } ,[ 1 10]_{{{M}_{ 2 3} {C}_{ 6} }} //[ 1 10]_{γ } . The flat M23C6/ γ coherent interface lies on the low indexed crystal planes {111}. Moreover, in M23C6/ γ coherent interface, there are embossments which stretch into the coherent austenite grain γ. Dislocations distribute in the embossments and coherent interface frontier. According to the experimental observation, the paper suggests that the embossments can promote the M23C6/ γ coherent interface move. Besides, the present work has analyzed chemical composition of experimental material and the crystal structures of austenite and M23C6, which indicates that the transformation can be completed through a little diffusion for C atoms and a simple variant for austenite unit cell.

Speed skills: measuring the visual speed analyzing properties of primate MT neurons.

PubMed

Perrone, J A; Thiele, A

2001-05-01

Knowing the direction and speed of moving objects is often critical for survival. However, it is poorly understood how cortical neurons process the speed of image movement. Here we tested MT neurons using moving sine-wave gratings of different spatial and temporal frequencies, and mapped out the neurons' spatiotemporal frequency response profiles. The maps typically had oriented ridges of peak sensitivity as expected for speed-tuned neurons. The preferred speed estimate, derived from the orientation of the maps, corresponded well to the preferred speed when moving bars were presented. Thus, our data demonstrate that MT neurons are truly sensitive to the object speed. These findings indicate that MT is not only a key structure in the analysis of direction of motion and depth perception, but also in the analysis of object speed.

Search for a light charged Higgs boson in the decay channel $$H^{+} \\rightarrow c\\bar{s}$$ in $$t\\bar{t}$$ events using pp collisions at $$\\sqrt{s} = 7\\ \\mathrm{TeV}$$ with the ATLAS detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aad, G.; Abajyan, T.; Abbott, B.

2013-06-06

A search for a charged Higgs boson (H +) inmore » $$t\\bar{t}$$decays is presented, where one of the top quarks decays via t →H + b, followed by H + → two jets ($$c\\bar{s}$$). The other top quark decays to Wb, where the W boson then decays into a lepton (e/μ) and a neutrino. The data were recorded in pp collisions at √ s = 7 TeV by the ATLAS detector at the LHC in 2011, and correspond to an integrated luminosity of 4.7 fb -1. Finally, with no observation of a signal, 95 % confidence level (CL) upper limits are set on the decay branching ratio of top quarks to charged Higgs bosons varying between 5 % and 1 % for H + masses between 90 GeV and 150 GeV, assuming B(H + →cs) = 100%.« less

Overview of the Development of Australian Combat Ration Packs

DTIC Science & Technology

2014-12-01

g) Variety B Serve Size (g) Retort Meal Chilli Con Carne 1 x 250 FD Meal Veal Italienne 1 x 110 Instant Oriental Noodles 1 x 74 White Rice 2 x 125...retort pouch meal freeze dried meal flexible retort pouch meal light meals (soup, noodles , steak bar, canned fish)  noodles steak bar...Items Common to all HWRP Menus Cracked Pepper Vita Wheat 1x36 g instant coffee 1x3.5 g tea bags# 1x2.5 g cheddar cheese (canned) 1x56 g cappuccino

Fiber optic coupling of a microlens conditioned, stacked semiconductor laser diode array

DOEpatents

Beach, Raymond J.; Benett, William J.; Mills, Steven T.

1997-01-01

The output radiation from the two-dimensional aperture of a semiconductor laser diode array is efficiently coupled into an optical fiber. The two-dimensional aperture is formed by stacking individual laser diode bars on top of another in a "rack and stack" configuration. Coupling into the fiber is then accomplished using individual microlenses to condition the output radiation of the laser diode bars. A lens that matches the divergence properties and wavefront characteristics of the laser light to the fiber optic is used to focus this conditioned radiation into the fiber.

KSR2 Is an Essential Regulator of AMP Kinase, Energy Expenditure, and Insulin Sensitivity

DTIC Science & Technology

2009-11-04

Metabolism 10, 366–378, November 4, 2009 ª2009 Elsevier Inc. acyl-CoA molecules into the mitochondria for oxidation. By inhibiting ACC, AMPK inhibits the...bars, n = 8 for each sex) and ksr2!/! mice (dark bars, n = 6 males, n = 11 females) during light (1 p.m.) and dark (9 p.m.) cycles (left panel). (C...impaired by the disruption of ksr2. Respiratory quotient (RQ) is lower in ksr2!/! mice during the dark cycle relative to wild-type mice (Figure 5A and

Alignment Tool For Inertia Welding

NASA Technical Reports Server (NTRS)

Snyder, Gary L.

1991-01-01

Compact, easy-to-use tool aligns drive bar of inertia welder over hole in stub. Ensures drive bar concentric to hole within 0.002 in. (0.051 mm.). Holds two batteries and light bulb. Electrical circuit completed, providing current to bulb when pin in contact with post. When pin centered in post hole, it does not touch post, and lamp turns off. Built for use in making repair welds on liquid-oxygen-injector posts in Space Shuttle main engine. Version having suitably modified dimensions used to facilitate alignment in other forests of post.

Bedload and river hydraulics - Inferences from the East Fork River, Wyoming

USGS Publications Warehouse

Leopold, Luna Bergere; Emmett, William W.

1997-01-01

During 1973-79, bedload data were collected in a sophisticated trap on a river of moderate size, the East Fork. The transport rate was measured most days through a full snowmelt season, and the rate was determined separately for eight zones across the channel width. The quantitative data are unique and unlikely to be repeated. Nor need they be, because as a result of this effort a practical bedload sampler was adequately tested against full river measurement.It was shown that bedload moves sporadically and randomly on the river bed. Therefore, transport rate is highly variable in short periods of time. There is also a wide variance from day to day. Yet, different rivers have transport rates, which are functions of discharge, depth, and sediment size, that are clearly distinct. Comparison of computed and measured transport rates indicates that a major problem remains: What grain size is representative of the bedload when there is a wide or heterogeneous particle-size distribution? Size of the bedload in motion may be very different from the size of bed material obtained from samples of the streambed.For general computation, the river channel slope may be averaged, and it may be assumed that water-surface slope does not change materially with changing discharge. Indeed, this generality is correct, in that, compared with depth, velocity, and width, slope is conservative at-a-station. However, in more detail, slope changes importantly with discharge in short reaches of channel, and those changes are very different in pool and riffle.These local changes in slope are not merely an aspect of a detailed longitudinal profile but involve cross-channel as well as down-channel components. The pool and riffle sequence involves not only undulation of bed elevation and bar formation on alternate sides of the channel, but alternation of the zone of superovulation of the water surface, and changing relation of watersurface slope to discharge. These details can be seen only in the full topography of the water surface. Riffles fill during high flow and scour at low flow. Changes in local water-surface slope illustrate this process. Pools are a storage zone for sediment in the low-flow season. Even though large volumes of sediment move, the distance moved is not large—in the East Fork River, sand of size 0.5-1 millimeter moved 650 meters during the 1979 snowmelt runoff season.Bedload transport is greatest over or near bars and not in the deepest part of the channel. Direct observation of the locus of sediment transport indicates that this locus moves from one side of the channel to the other in concert with the occurrence of alternate bars. Separately, data indicate that at constant stream power, transport rate increases as depth decreases.

77 FR 52 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 23

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-03

... located in front of the depressor plate. (2) The angle between the front edge of the cutting bar and the... and under the depressor plate, impeding a sea turtle from rising above the dredge. By moving the... their scallop trips before being able to fish. The Council may choose to address this issue in other VMS...

Raising the Bar for the Training of College Teachers: An Interview with Victor Benassi

ERIC Educational Resources Information Center

Wimer, David J.

2006-01-01

Victor A. Benassi earned his bachelor's degree from California State College and his PhD in psychology from the City University of New York. After working in the Department of Psychology at California State University at Long Beach, he moved to the University of New Hampshire (UNH) in 1982. He is currently Professor of Psychology and Professor of…

Application of high-speed photography to chip refining

NASA Astrophysics Data System (ADS)

Stationwala, Mustafa I.; Miller, Charles E.; Atack, Douglas; Karnis, A.

1991-04-01

Several high speed photographic methods have been employed to elucidate the mechanistic aspects of producing mechanical pulp in a disc refiner. Material flow patterns of pulp in a refmer were previously recorded by means of a HYCAM camera and continuous lighting system which provided cine pictures at up to 10,000 pps. In the present work an IMACON camera was used to obtain several series of high resolution, high speed photographs, each photograph containing an eight-frame sequence obtained at a framing rate of 100,000 pps. These high-resolution photographs made it possible to identify the nature of the fibrous material trapped on the bars of the stationary disc. Tangential movement of fibre floes, during the passage of bars on the rotating disc over bars on the stationary disc, was also observed on the stator bars. In addition, using a cinestroboscopic technique a large number of high resolution pictures were taken at three different positions of the rotating disc relative to the stationary disc. These pictures were computer analyzed, statistically, to determine the fractional coverage of the bars of the stationary disc with pulp. Information obtained from these studies provides new insights into the mechanism of the refining process.

Procedure for utilizing the lift and thrust forces of ornithopters

NASA Technical Reports Server (NTRS)

Bezard, C.

1985-01-01

This procedure is distinguished by two beating wings which together describe, in space, a succession of interlaced triangles. On these wings, whose incidence varies automatically, identical forces are exerted: simultaneous lift and thrust when they make their descent, which is inclined toward the front of the craft, and lift alone when they make their ascent, which is inclined toward the rear of the craft and follows a slide horizontal movement. A mechanical device makes these movements possible. It includes: two wings with hollow profiles, connected by a framework located above a rigid frame and attached to it by bars with joints. These bars are moved with control rods which gear down the drive force. A mechanism with elastic bands or springs automatically varies the incidence of the wings.

Load Variation Influences on Joint Work During Squat Exercise in Reduced Gravity

NASA Technical Reports Server (NTRS)

DeWitt, John K.; Fincke, Renita S.; Logan, Rachel L.; Guilliams, Mark E.; Ploutz-Snyder, Lori L.

2011-01-01

Resistance exercises that load the axial skeleton, such as the parallel squat, are incorporated as a critical component of a space exercise program designed to maximize the stimuli for bone remodeling and muscle loading. Astronauts on the International Space Station perform regular resistance exercise using the Advanced Resistive Exercise Device (ARED). Squat exercises on Earth entail moving a portion of the body weight plus the added bar load, whereas in microgravity the body weight is 0, so all load must be applied via the bar. Crewmembers exercising in microgravity currently add approx.70% of their body weight to the bar load as compensation for the absence of the body weight. This level of body weight replacement (BWR) was determined by crewmember feedback and personal experience without any quantitative data. The purpose of this evaluation was to utilize computational simulation to determine the appropriate level of BWR in microgravity necessary to replicate lower extremity joint work during squat exercise in normal gravity based on joint work. We hypothesized that joint work would be positively related to BWR load.

A new mechanically braked bicycle ergometer with electronic read out.

PubMed

Bonde-Petersen, F

1983-01-01

The ergometer is mechanically braked by a band in series with a spring. Each end of the band passes over one of two spherical ball bearings, and is attached to the free end of a spring steel bar mounted on the same plate as the two ball bearings. By means of a spindle and cogwheel the plate can be tilted in such a way as to vary the tension in the braking band. The spring steel bar is furnished with four strain-gauges coupled as a Wheatstone's bridge. The system forms a differential force transducer measuring the differences in tension between the two ends of the band. A force is, therefore, only recorded if the flywheel is moving, because at rest forces influencing the bar from the band will be opposite and equal. The ergometer offers certain advantages over the conventional mechanically braked ergometers because it has an electronic read out, and it can be used in field studies. It is independent of the attitude in relation to the vertical, and can thus be used on tilting platforms or in weightless conditions.

Functional Analysis With a Barcoder Yeast Gene Overexpression System

PubMed Central

Douglas, Alison C.; Smith, Andrew M.; Sharifpoor, Sara; Yan, Zhun; Durbic, Tanja; Heisler, Lawrence E.; Lee, Anna Y.; Ryan, Owen; Göttert, Hendrikje; Surendra, Anu; van Dyk, Dewald; Giaever, Guri; Boone, Charles; Nislow, Corey; Andrews, Brenda J.

2012-01-01

Systematic analysis of gene overexpression phenotypes provides an insight into gene function, enzyme targets, and biological pathways. Here, we describe a novel functional genomics platform that enables a highly parallel and systematic assessment of overexpression phenotypes in pooled cultures. First, we constructed a genome-level collection of ~5100 yeast barcoder strains, each of which carries a unique barcode, enabling pooled fitness assays with a barcode microarray or sequencing readout. Second, we constructed a yeast open reading frame (ORF) galactose-induced overexpression array by generating a genome-wide set of yeast transformants, each of which carries an individual plasmid-born and sequence-verified ORF derived from the Saccharomyces cerevisiae full-length EXpression-ready (FLEX) collection. We combined these collections genetically using synthetic genetic array methodology, generating ~5100 strains, each of which is barcoded and overexpresses a specific ORF, a set we termed “barFLEX.” Additional synthetic genetic array allows the barFLEX collection to be moved into different genetic backgrounds. As a proof-of-principle, we describe the properties of the barFLEX overexpression collection and its application in synthetic dosage lethality studies under different environmental conditions. PMID:23050238

Light propagation in the Solar System for astrometry on sub-micro-arcsecond level

NASA Astrophysics Data System (ADS)

Zschocke, Sven

2018-04-01

We report on recent advancement in the theory of light propagation in the Solar System aiming at sub-micro-arcsecond level of accuracy: (1) A solution for the light ray in 1.5PN approximation has been obtained in the field of N arbitrarily moving bodies of arbitrary shape, inner structure, oscillations, and rotational motion. (2) A solution for the light ray in 2PN approximation has been obtained in the field of one arbitrarily moving pointlike body.

Multisensory Motion Perception in 3–4 Month-Old Infants

PubMed Central

Nava, Elena; Grassi, Massimo; Brenna, Viola; Croci, Emanuela; Turati, Chiara

2017-01-01

Human infants begin very early in life to take advantage of multisensory information by extracting the invariant amodal information that is conveyed redundantly by multiple senses. Here we addressed the question as to whether infants can bind multisensory moving stimuli, and whether this occurs even if the motion produced by the stimuli is only illusory. Three- to 4-month-old infants were presented with two bimodal pairings: visuo-tactile and audio-visual. Visuo-tactile pairings consisted of apparently vertically moving bars (the Barber Pole illusion) moving in either the same or opposite direction with a concurrent tactile stimulus consisting of strokes given on the infant’s back. Audio-visual pairings consisted of the Barber Pole illusion in its visual and auditory version, the latter giving the impression of a continuous rising or ascending pitch. We found that infants were able to discriminate congruently (same direction) vs. incongruently moving (opposite direction) pairs irrespective of modality (Experiment 1). Importantly, we also found that congruently moving visuo-tactile and audio-visual stimuli were preferred over incongruently moving bimodal stimuli (Experiment 2). Our findings suggest that very young infants are able to extract motion as amodal component and use it to match stimuli that only apparently move in the same direction. PMID:29187829

NICMOS FINDS A GOLDEN RING AT THE HEART OF A GALAXY

NASA Technical Reports Server (NTRS)

2002-01-01

The revived Near Infrared Camera and Multi-Object Spectrometer (NICMOS) aboard NASA's Hubble Space Telescope has pierced the dusty disk of the 'edge-on' galaxy NGC 4013 and peered all the way to the galactic core. To the surprise of astronomers, NICMOS found a brilliant band-like structure, that may be a ring of newly formed stars [yellow band in middle photo] seen edge-on. In the visible-light view of the galaxy [top photo], the star-forming ring cannot be seen because it is embedded in dust. The most prominent feature in the visible-light image -- taken by the Wide Field and Planetary Camera 2 (WFPC2) -- is the thin, dark band of gas and dust, which is about 500 light-years thick. NICMOS enables the Hubble telescope to see in near-infrared wavelengths of light, so that it can penetrate the dust that obscures the inner hub of the galaxy. The ring-like structure spied by NICMOS encircles the core and is about 720 light-years wide, which is the typical size of most star-forming rings found in disk galaxies. The small ring is churning out stars at a torrid pace. The Milky Way Galaxy, for example, is more than 10,000 times larger than the ring. If the Milky Way produced stars at the same rate, it would be making 1,000 times more stars a year. The human eye cannot see infrared light, so colors have been assigned to correspond with near-infrared wavelengths. The blue light represents shorter near-infrared wavelengths and the red light corresponds to longer wavelengths. The ring-like structure is seen more clearly in the photo at bottom. This picture, taken with a filter sensitive to hydrogen, shows the glow of stars and gas. Astronomers used this information to calculate the rate of star formation in the ring-like structure. The extremely bright star near the center of each picture is a nearby foreground star belonging to our own Milky Way. Rings of developing stars are common in barred spiral galaxies, which have 'bars' of stars and gas slicing across their disks. The bars funnel gas to the galactic cores. But gravitational disturbances near the cores cause gas to accumulate into a lane or a ring. The gas then condenses to form stars. Because NGC 4013 is seen edge-on, astronomers don't know whether a bar of gas or some other mechanism formed the ring-like structure. NGC 4013, which looks similar to our Milky Way Galaxy, resides in the constellation Ursa Major, 55 million light-years from Earth. The middle picture is a color composite image that was made by combining photographs taken with the J-band, H-band, and Paschen-alpha filters. The bottom picture was taken with the Paschen-alpha filter. The images were taken on May 12. Credits for NICMOS images: NASA, the NICMOS Group (STScI, ESA), and the NICMOS Science Team (University of Arizona) Credits for WFPC2 image: NASA, the Hubble Heritage Team (STScI/AURA) and ESA

Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from pp-bar; Collisions at √s = 1.96 TeV

DOE PAGES

Aaltonen, T.

2011-07-11

We present the results of a search for a very light CP-odd Higgs boson a 1 0 originating from top quark decays t→H ±b → W ±(*)a 1 0b, and subsequently decaying into τ +τ -. Using a data sample corresponding to an integrated luminosity of 2.7 fb -1 collected by the CDF II detector in pp-bar collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20 GeV/c. Observed events are consistent with background sources, and 95% C.L. limitsmore » are set on the branching ratio of t→H ±b for various masses of H ± and a 1 0.« less

Influence of agronomic variables on the composition of mate tea leaves (Ilex paraguariensis) extracts obtained from CO2 extraction at 30 degrees C and 175 bar.

PubMed

Esmelindro, Angela Aquino; Girardi, Jonathan Dos Santos; Mossi, Altemir; Jacques, Rosângela Assis; Dariva, Cláudio

2004-04-07

The aim of this work is to assess the influence of light intensity (plants with direct sun exposure and in a controlled light intensity) and age of leaves (6-24 months) on the characteristics of the extracts of mate tea leaves obtained from carbon dioxide at high pressures. Samples of mate were collected in an experiment conducted under agronomic control at Industria e Comercio de Erva-Mate Barão LTDA, Brazil. The content of selected organic compounds of the extracts was evaluated by gas chromatography together with mass spectrometry. Quantitative analysis of caffeine, theobromine, phytol, vitamin E, squalene, and stigmasterol was performed, and the results showed that field variables exert a strong influence on the liquid yield and on the chemical distribution of the extracts.

Plasmonic Circuit Theory for Multiresonant Light Funneling to a Single Spatial Hot Spot.

PubMed

Hughes, Tyler W; Fan, Shanhui

2016-09-14

We present a theoretical framework, based on plasmonic circuit models, for generating a multiresonant field intensity enhancement spectrum at a single "hot spot" in a plasmonic device. We introduce a circuit model, consisting of an array of coupled LC resonators, that directs current asymmetrically in the array, and we show that this circuit can funnel energy efficiently from each resonance to a single element. We implement the circuit model in a plasmonic nanostructure consisting of a series of metal bars of differing length, with nearest neighbor metal bars strongly coupled electromagnetically through air gaps. The resulting nanostructure resonantly traps different wavelengths of incident light in separate gap regions, yet it funnels the energy of different resonances to a common location, which is consistent with our circuit model. Our work is important for a number of applications of plasmonic nanoantennas in spectroscopy, such as in single-molecule fluorescence spectroscopy or Raman spectroscopy.

Scintillation Detector for the Measurement of Ultra-Heavy Cosmic Rays on the Super-TIGER Experiment

NASA Technical Reports Server (NTRS)

Link, Jason

2011-01-01

We discuss the design and construction of the scintillation detectors for the Super-TIGER experiment. Super-TIGER is a large-area (5.4sq m) balloon-borne experiment designed to measure the abundances of cosmic-ray nuclei between Z= 10 and Z=56. It is based on the successful TIGER experiment that flew in Antarctica in 2001 and 2003. Super-TIGER has three layers of scintillation detectors, two Cherenkov detectors and a scintillating fiber hodoscope. The scintillation detector employs four wavelength shifter bars surrounding the edges of the scintillator to collect the light from particles traversing the detector. PMTs are optically coupled at both ends of the bars for light collection. We report on laboratory performance of the scintillation counters using muons. In addition we discuss the design challenges and detector response over this broad charge range including the effect of scintilator saturation.

Linear encoding device

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

1993-01-01

A Linear Motion Encoding device for measuring the linear motion of a moving object is disclosed in which a light source is mounted on the moving object and a position sensitive detector such as an array photodetector is mounted on a nearby stationary object. The light source emits a light beam directed towards the array photodetector such that a light spot is created on the array. An analog-to-digital converter, connected to the array photodetector is used for reading the position of the spot on the array photodetector. A microprocessor and memory is connected to the analog-to-digital converter to hold and manipulate data provided by the analog-to-digital converter on the position of the spot and to compute the linear displacement of the moving object based upon the data from the analog-to-digital converter.

A comparison of peak power in the shoulder press and shoulder throw.

PubMed

Dalziel, W M; Neal, R J; Watts, M C

2002-09-01

The ability to generate peak power is central for performance in many sports. Currently two distinct resistance training methods are used to develop peak power, the heavy weight/slow velocity and light weight/fast velocity regimes. When using the light weight/fast velocity power training method it was proposed that peak power would be greater in a shoulder throw exercise compared with a normal shoulder press. Nine males performed three lifts in the shoulder press and shoulder throw at 30% and 40% of their one repetition maximum (1RM). These lifts were performed identically, except for the release of the bar in the throw condition. A potentiometer attached to the bar measured displacement and duration of the lifts. The time of bar release in the shoulder throw was determined with a pressure switch. ANOVA was used to examine statistically significant differences where the level of acceptance was set at p < 0.05. Peak power was found to be significantly greater in the shoulder throw at 30% of 1 RM condition [F, (1, 23) = 2.325 p < 0.051 and at 40% of 1 RM [F, (1, 23) = 2.905 p < 0.05] compared to values recorded for the respective shoulder presses. Peak power was also greater in the 30% of 1 RM shoulder throw (510 +/- 103W) than in the 40% of 1 RM shoulder press (471 +/- 96W). Peak power was produced significantly later in the shoulder throw versus the shoulder press. This differing power reflected a greater bar velocity of the shoulder throw at both assigned weights compared with the shoulder press.

Gravel sediment routing from widespread, low-intensity landscape disturbance, Current River basin, Missouri

USGS Publications Warehouse

Jacobson, Robert B.; Gran, K.B.

1999-01-01

During the last 160 years, land-use changes in the Ozarks have had the potential to cause widespread, low-intensity delivery of excess amounts of gravel-sized sediment to stream channels. Previous studies have indicated that this excess gravel bedload is moving in wave-like forms through Ozarks drainage basins. The longitudinal, areal distribution of gravel bars along 160 km of the Current River, Missouri, was evaluated to determine the relative effects of valley-scale controls, tributary basin characteristics, and lagged sediment transport in creating areas of gravel accumulations. The longitudinal distribution of gravel-bar area shows a broad scale wave-like form with increases in gravel-bar area weakly associated with tributary junctions. Secondary peaks of gravel area with 1·8–4·1 km spacing (disturbance reaches) are superimposed on the broad form. Variations in valley width explain some, but not all, of the short-spacing variation in gravel-bar area. Among variables describing tributary drainage basin morphometry, present-day land use and geologic characteristics, only drainage area and road density relate even weakly to gravel-bar areal inventories. A simple, channel network-based sediment routing model shows that many of the features of the observed longitudinal gravel distribution can be replicated by uniform transport of sediment from widespread disturbances through a channel network. These results indicate that lagged sediment transport may have a dominant effect on the synoptic spatial distribution of gravel in Ozarks streams; present-day land uses are only weakly associated with present-day gravel inventories; and valley-scale characteristics have secondary controls on gravel accumulations in disturbance reaches.

Pressure probe study of the water relations of Phycomyces blakesleeanus sporangiophores

NASA Technical Reports Server (NTRS)

Cosgrove, D. J.; Ortega, J. K.; Shropshire, W. Jr

1987-01-01

The physical characteristics which govern the water relations of the giant-celled sporangiophore of Phycomyces blakesleeanus were measured with the pressure probe technique and with nanoliter osmometry. These properties are important because they govern water uptake associated with cell growth and because they may influence expansion of the sporangiophore wall. Turgor pressure ranged from 1.1 to 6.6 bars (mean = 4.1 bars), and was the same for stage I and stage IV sporangiophores. Sporangiophore osmotic pressure averaged 11.5 bars. From the difference between cell osmotic pressure and turgor pressure, the average water potential of the sporangiophore was calculated to be about -7.4 bars. When sporangiophores were submerged under water, turgor remained nearly constant. We propose that the low cell turgor pressure is due to solutes in the cell wall solution, i.e., between the cuticle and the plasma membrane. Membrane hydraulic conductivity averaged 4.6 x 10(-6) cm s-1 bar-1, and was significantly greater in stage I sporangiophores than in stage IV sporangiophores. Contrary to previous reports, the sporangiophore is separated from the supporting mycelium by septa which prevent bulk volume flow between the two regions. The presence of a wall compartment between the cuticle and the plasma membrane results in anomalous osmosis during pressure clamp measurements. This behavior arises because of changes in solute concentration as water moves into or out of the wall compartment surrounding the sporangiophore. Theoretical analysis shows how the equations governing transient water flow are altered by the characteristics of the cell wall compartment.

A study of extraterrestrial antineutrino sources with the KamLAND detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

The KamLAND Collaboration; Gando, A.; Gando, Y.

2011-05-18

We present the results of a search for extraterrestrial electron antineutrinos ({bar {nu}}{sub e}'s) in the energy range 8.3 MeV < E{sub {bar {nu}}}{sub e} < 30.8 MeV using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of {sup 8}B solar {nu}{sub e}'s converting into {bar {nu}}{sub e}'s at 5.3 x 10{sup -5} (90% C.L.). The present data also allows us to set more stringent limits on the diffuse supernovamore » neutrino flux and on the annihilation rates for light dark matter particles.« less

Effect of high-pressure homogenization preparation on mean globule size and large-diameter tail of oil-in-water injectable emulsions.

PubMed

Peng, Jie; Dong, Wu-Jun; Li, Ling; Xu, Jia-Ming; Jin, Du-Jia; Xia, Xue-Jun; Liu, Yu-Ling

2015-12-01

The effect of different high pressure homogenization energy input parameters on mean diameter droplet size (MDS) and droplets with > 5 μm of lipid injectable emulsions were evaluated. All emulsions were prepared at different water bath temperatures or at different rotation speeds and rotor-stator system times, and using different homogenization pressures and numbers of high-pressure system recirculations. The MDS and polydispersity index (PI) value of the emulsions were determined using the dynamic light scattering (DLS) method, and large-diameter tail assessments were performed using the light-obscuration/single particle optical sensing (LO/SPOS) method. Using 1000 bar homogenization pressure and seven recirculations, the energy input parameters related to the rotor-stator system will not have an effect on the final particle size results. When rotor-stator system energy input parameters are fixed, homogenization pressure and recirculation will affect mean particle size and large diameter droplet. Particle size will decrease with increasing homogenization pressure from 400 bar to 1300 bar when homogenization recirculation is fixed; when the homogenization pressure is fixed at 1000 bar, the particle size of both MDS and percent of fat droplets exceeding 5 μm (PFAT 5 ) will decrease with increasing homogenization recirculations, MDS dropped to 173 nm after five cycles and maintained this level, volume-weighted PFAT 5 will drop to 0.038% after three cycles, so the "plateau" of MDS will come up later than that of PFAT 5 , and the optimal particle size is produced when both of them remained at plateau. Excess homogenization recirculation such as nine times under the 1000 bar may lead to PFAT 5 increase to 0.060% rather than a decrease; therefore, the high-pressure homogenization procedure is the key factor affecting the particle size distribution of emulsions. Varying storage conditions (4-25°C) also influenced particle size, especially the PFAT 5 . Copyright © 2015. Published by Elsevier B.V.

Standards Get Boost on the Hill: Bills before Congress Aim to Raise the Bar in States

ERIC Educational Resources Information Center

Olson, Lynn

2007-01-01

This article focuses on the standards debate in the context of renewing the 5-year-old No Child Left Behind Act. The politically sensitive idea of increasing the rigor of state standards and tests by linking them to standards set at the national level is getting a push from prominent lawmakers as Congress moves to reauthorize the No Child Left…

Eddy-Current Detection of Cracks in Tubes

NASA Technical Reports Server (NTRS)

Parent, R.; Kettering, D.

1987-01-01

Nondestructive device tests narrow, sharply-bent metal tubes. Eddycurrent probe detects incipient cracks inside small metal tubes. Tube-centering device consisting of pair of opposed bars ensures tube centered on eddy-current coil. Probe moves along length of bent tube to inspect repeatably for cracks. Compatible with tubes of different cross sections, oval, flattened, square, rectangular,or irregular. Adapts for inspecting formed tubes in petrochemical, automotive, nuclear, and medical equipment.

Phenotype-limited distributions: short-billed birds move away during times that prey bury deeply

PubMed Central

Duijns, Sjoerd; van Gils, Jan A.; Smart, Jennifer; Piersma, Theunis

2015-01-01

In our seasonal world, animals face a variety of environmental conditions in the course of the year. To cope with such seasonality, animals may be phenotypically flexible, but some phenotypic traits are fixed. If fixed phenotypic traits are functionally linked to resource use, then animals should redistribute in response to seasonally changing resources, leading to a ‘phenotype-limited’ distribution. Here, we examine this possibility for a shorebird, the bar-tailed godwit (Limosa lapponica; a long-billed and sexually dimorphic shorebird), that has to reach buried prey with a probing bill of fixed length. The main prey of female bar-tailed godwits is buried deeper in winter than in summer. Using sightings of individually marked females, we found that in winter only longer-billed individuals remained in the Dutch Wadden Sea, while the shorter-billed individuals moved away to an estuary with a more benign climate such as the Wash. Although longer-billed individuals have the widest range of options in winter and could therefore be selected for, counterselection may occur during the breeding season on the tundra, where surface-living prey may be captured more easily with shorter bills. Phenotype-limited distributions could be a widespread phenomenon and, when associated with assortative migration and mating, it may act as a precursor of phenotypic evolution. PMID:26543585

Phenotype-limited distributions: short-billed birds move away during times that prey bury deeply.

PubMed

Duijns, Sjoerd; van Gils, Jan A; Smart, Jennifer; Piersma, Theunis

2015-06-01

In our seasonal world, animals face a variety of environmental conditions in the course of the year. To cope with such seasonality, animals may be phenotypically flexible, but some phenotypic traits are fixed. If fixed phenotypic traits are functionally linked to resource use, then animals should redistribute in response to seasonally changing resources, leading to a 'phenotype-limited' distribution. Here, we examine this possibility for a shorebird, the bar-tailed godwit (Limosa lapponica; a long-billed and sexually dimorphic shorebird), that has to reach buried prey with a probing bill of fixed length. The main prey of female bar-tailed godwits is buried deeper in winter than in summer. Using sightings of individually marked females, we found that in winter only longer-billed individuals remained in the Dutch Wadden Sea, while the shorter-billed individuals moved away to an estuary with a more benign climate such as the Wash. Although longer-billed individuals have the widest range of options in winter and could therefore be selected for, counterselection may occur during the breeding season on the tundra, where surface-living prey may be captured more easily with shorter bills. Phenotype-limited distributions could be a widespread phenomenon and, when associated with assortative migration and mating, it may act as a precursor of phenotypic evolution.

Watching single molecules dance

NASA Astrophysics Data System (ADS)

Mehta, Amit Dinesh

Molecular motors convert chemical energy, from ATP hydrolysis or ion flow, into mechanical motion. A variety of increasingly precise mechanical probes have been developed to monitor and perturb these motors at the single molecule level. Several outstanding questions can be best approached at the single molecule level. These include: how far does a motor progress per energy quanta consumed? how does its reaction cycle respond to load? how many productive catalytic cycles can it undergo per diffusional encounter with its track? and what is the mechanical stiffness of a single molecule connection? A dual beam optical trap, in conjunction with in vitro ensemble motility assays, has been used to characterize two members of the myosin superfamily: muscle myosin II and chick brain myosin V. Both move the helical polymer actin, but myosin II acts in large ensembles to drive muscle contraction or cytokinesis, while myosin V acts in small numbers to transport vesicles. An optical trapping apparatus was rendered sufficiently precise to identify a myosin working stroke with 1nm or so, barring systematic errors such as those perhaps due to random protein orientations. This and other light microscopic motility assays were used to characterize myosin V: unlike myosin II this vesicle transport protein moves through many increments of travel while remaining strongly bound to a single actin filament. The step size, stall force, and travel distance of myosin V reveal a remarkably efficient motor capable of moving along a helical track for over a micrometer without significantly spiraling around it. Such properties are fully consistent with the putative role of an organelle transport motor, present in small numbers to maintain movement over long ranges relative to cellular size scales. The contrast between myosin II and myosin V resembles that between a human running on the moon and one walking on earth, where the former allows for faster motion when in larger ensembles but for less travel distance when in smaller ones.

Fiber optic coupling of a microlens conditioned, stacked semiconductor laser diode array

DOEpatents

Beach, R.J.; Benett, W.J.; Mills, S.T.

1997-04-01

The output radiation from the two-dimensional aperture of a semiconductor laser diode array is efficiently coupled into an optical fiber. The two-dimensional aperture is formed by stacking individual laser diode bars on top of another in a ``rack and stack`` configuration. Coupling into the fiber is then accomplished using individual microlenses to condition the output radiation of the laser diode bars. A lens that matches the divergence properties and wavefront characteristics of the laser light to the fiber optic is used to focus this conditioned radiation into the fiber. 3 figs.

Efficiency Measurement of VANDLE Modules

NASA Astrophysics Data System (ADS)

Peters, William; Matei, C.; Cizewski, J. A.; O'Malley, P. D.; Spassova, I.; Bardayan, D.; Blackmon, J. C.; Brune, C.; Massey, T.; Grzywacz, R. K.; Madurga, M.; Sarazin, F.; Raiola, F.

2010-02-01

The Versatile Array of Neutron Detectors at Low Energy (VANDLE) is a new array of plastic scintillator bars being developed at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL). The modular design enables optimization of different configurations for particular experiments, such as (d,n) and beta-delayed neutron-decay experiments, with rare ion beams. Two prototype modules were moved to the Edwards Accelerator Laboratory at Ohio University to measure their efficiency using a calibrated ^27Al(d,n) reaction as a neutron source. Results show that one bar with a cross section of 3x3 cm^2 is over 25% efficient to neutrons around 1 MeV with sensitivity down to 100 keV neutrons. Other design features such as wrapping and coupling will be presented, as well as results from resolution tests. )

Social and Structural Constraints on Disclosure and Informed Consent for HIV Survey Research Involving Female Sex Workers and their Bar Managers in the Philippines

PubMed Central

Urada, Lianne A.; Simmons, Janie

2014-01-01

This qualitative study explored the ethical issues of female sex workers’ (FSWs) participation in HIV prevention research. Twenty female bar/spa workers and 10 venue managers in the Philippines underwent individual semi-structured interviews; three community advisory board meetings informed the study design and interpretation of findings. Results: Informed consent was constrained by perceived government coercion and skepticism that research results would translate into community benefits. Disclosure was constrained by distrust in confidentiality and perceived intrusiveness of survey questions. FSWs and managers were frustrated by the government's inability to stop police from using condoms as evidence of prostitution. Findings suggest HIV interventions move beyond didactic prevention workshops to include FSWs in intervention design and implementation, and to reduce social and structural constraints on participation. PMID:24572081

Light-fuelled transport of large dendrimers and proteins.

PubMed

Koskela, Jenni E; Liljeström, Ville; Lim, Jongdoo; Simanek, Eric E; Ras, Robin H A; Priimagi, Arri; Kostiainen, Mauri A

2014-05-14

This work presents a facile water-based supramolecular approach for light-induced surface patterning. The method is based upon azobenzene-functionalized high-molecular weight triazine dendrimers up to generation 9, demonstrating that even very large globular supramolecular complexes can be made to move in response to light. We also demonstrate light-fuelled macroscopic movements in native biomolecules, showing that complexes of apoferritin protein and azobenzene can effectively form light-induced surface patterns. Fundamentally, the results establish that thin films comprising both flexible and rigid globular particles of large diameter can be moved with light, whereas the presented material concepts offer new possibilities for the yet marginally explored biological applications of azobenzene surface patterning.

Emission wavelength tuning of fluorescence by fine structural control of optical metamaterials with Fano resonance

PubMed Central

Moritake, Y.; Kanamori, Y.; Hane, K.

2016-01-01

We demonstrated fine emission wavelength tuning of quantum dot (QD) fluorescence by fine structural control of optical metamaterials with Fano resonance. An asymmetric-double-bar (ADB), which was composed of only two bars with slightly different bar lengths, was used to obtain Fano resonance in the optical region. By changing the short bar length of ADB structures with high dimensional accuracy in the order of 10 nm, resonant wavelengths of Fano resonance were controlled from 1296 to 1416 nm. Fluorescence of QDs embedded in a polymer layer on ADB metamaterials were modified due to coupling to Fano resonance and fine tuning from 1350 to 1376 nm was observed. Wavelength tuning of modified fluorescence was reproduced by analysis using absorption peaks of Fano resonance. Tuning range of modified fluorescence became narrow, which was interpreted by a simple Gaussian model and resulted from comparable FWHM in QD fluorescence and Fano resonant peaks. The results will help the design and fabrication of metamaterial devices with fluorophores such as light sources and biomarkers. PMID:27622503

A Compliant Four-bar Linkage Mechanism that Makes the Fingers of a Prosthetic Hand More Impact Resistant

PubMed Central

Choi, Kyung Yun; Akhtar, Aadeel; Bretl, Timothy

2017-01-01

Repeated mechanical failure due to accidental impact is one of the main reasons why people with upper-limb amputations abandon commercially-available prosthetic hands. To address this problem, we present the design and evaluation of a compliant four-bar linkage mechanism that makes the fingers of a prosthetic hand more impact resistant. Our design replaces both the rigid input and coupler links with a monolithic compliant bone, and replaces the follower link with three layers of pre-stressed spring steel. This design behaves like a conventional four-bar linkage but adds lateral compliance and eliminates a pin joint, which is a main site of failure on impact. Results from free-end and fixed-end impact tests show that, compared to those made with a conventional four-bar linkage, fingers made with our design absorb up to 11% more energy on impact with no mechanical failure. We also show the integration of these fingers in a prosthetic hand that is low-cost, light-weight, and easy to assemble, and that has grasping performance comparable to commercially-available hands. PMID:29527386

Deformation of periodic nanovoid structures in Mg single crystals

NASA Astrophysics Data System (ADS)

Xu, Shuozhi; Su, Yanqing; Zare Chavoshi, Saeed

2018-01-01

Large scale molecular dynamics (MD) simulations in Mg single crystal containing periodic cylindrical voids subject to uniaxial tension along the z direction are carried out. Models with different initial void sizes and crystallographic orientations are explored using two interatomic potentials. It is found that (i) a larger initial void always leads to a lower yield stress, in agreement with an analytic prediction; (ii) in the model with x[\\bar{1}100]-y[0001]-z[11\\bar{2}0] orientations, the two potentials predict different types of tension twins and phase transformation; (iii) in the model with x[0001]-y[11\\bar{2}0]-z[\\bar{1}100] orientations, the two potentials identically predict the nucleation of edge dislocations on the prismatic plane, which then glide away from the void, resulting in extrusions at the void surface; in the case of the smallest initial void, these surface extrusions pinch the void into two voids. Besides bringing new physical understanding of the nanovoid structures, our work highlights the variability and uncertainty in MD simulations arising from the interatomic potential, an issue relatively lightly addressed in the literature to date.

Constraints on new physics from K → π ν {\\bar{ν }}

NASA Astrophysics Data System (ADS)

He, Xiao-Gang; Valencia, German; Wong, Keith

2018-06-01

We study generic effects of new physics on the rare decay modes K_L → π ^0 ν {\\bar{ν }} and K^+ → π ^+ ν {\\bar{ν }}. We discuss several cases: left-handed neutrino couplings; right handed neutrino couplings; neutrino lepton flavour violating (LFV) interactions; and Δ I =3/2 interactions. The first of these cases has been studied before as it covers many new physics extensions of the standard model; the second one requires the existence of a new light (sterile) right-handed neutrino and its contribution to both branching ratios is always additive to the SM. The case of neutrino LFV couplings introduces a CP conserving contribution to K_L → π ^0 ν {\\bar{ν }} which affects the rates in a similar manner as a right handed neutrino as neither one of these interferes with the standard model amplitudes. Finally, we consider new physics with Δ I =3/2 interactions to go beyond the Grossman-Nir bound. We find that the rare kaon rates are only sensitive to new physics scales up to a few GeV for this scenario.

Time-of-flight depth image enhancement using variable integration time

NASA Astrophysics Data System (ADS)

Kim, Sun Kwon; Choi, Ouk; Kang, Byongmin; Kim, James Dokyoon; Kim, Chang-Yeong

2013-03-01

Time-of-Flight (ToF) cameras are used for a variety of applications because it delivers depth information at a high frame rate. These cameras, however, suffer from challenging problems such as noise and motion artifacts. To increase signal-to-noise ratio (SNR), the camera should calculate a distance based on a large amount of infra-red light, which needs to be integrated over a long time. On the other hand, the integration time should be short enough to suppress motion artifacts. We propose a ToF depth imaging method to combine advantages of short and long integration times exploiting an imaging fusion scheme proposed for color imaging. To calibrate depth differences due to the change of integration times, a depth transfer function is estimated by analyzing the joint histogram of depths in the two images of different integration times. The depth images are then transformed into wavelet domains and fused into a depth image with suppressed noise and low motion artifacts. To evaluate the proposed method, we captured a moving bar of a metronome with different integration times. The experiment shows the proposed method could effectively remove the motion artifacts while preserving high SNR comparable to the depth images acquired during long integration time.

On wave dark matter in spiral and barred galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez-Medina, Luis A.; Matos, Tonatiuh; Bray, Hubert L., E-mail: lmedina@fis.cinvestav.mx, E-mail: bray@math.duke.edu, E-mail: tmatos@fis.cinvestav.mx

2015-12-01

We recover spiral and barred spiral patterns in disk galaxy simulations with a Wave Dark Matter (WDM) background (also known as Scalar Field Dark Matter (SFDM), Ultra-Light Axion (ULA) dark matter, and Bose-Einstein Condensate (BEC) dark matter). Here we show how the interaction between a baryonic disk and its Dark Matter Halo triggers the formation of spiral structures when the halo is allowed to have a triaxial shape and angular momentum. This is a more realistic picture within the WDM model since a non-spherical rotating halo seems to be more natural. By performing hydrodynamic simulations, along with earlier test particlesmore » simulations, we demonstrate another important way in which wave dark matter is consistent with observations. The common existence of bars in these simulations is particularly noteworthy. This may have consequences when trying to obtain information about the dark matter distribution in a galaxy, the mere presence of spiral arms or a bar usually indicates that baryonic matter dominates the central region and therefore observations, like rotation curves, may not tell us what the DM distribution is at the halo center. But here we show that spiral arms and bars can develop in DM dominated galaxies with a central density core without supposing its origin on mechanisms intrinsic to the baryonic matter.« less

Uncertainty in the delayed neutron fraction in fuel assembly depletion calculations

NASA Astrophysics Data System (ADS)

Aures, Alexander; Bostelmann, Friederike; Kodeli, Ivan A.; Velkov, Kiril; Zwermann, Winfried

2017-09-01

This study presents uncertainty and sensitivity analyses of the delayed neutron fraction of light water reactor and sodium-cooled fast reactor fuel assemblies. For these analyses, the sampling-based XSUSA methodology is used to propagate cross section uncertainties in neutron transport and depletion calculations. Cross section data is varied according to the SCALE 6.1 covariance library. Since this library includes nu-bar uncertainties only for the total values, it has been supplemented by delayed nu-bar uncertainties from the covariance data of the JENDL-4.0 nuclear data library. The neutron transport and depletion calculations are performed with the TRITON/NEWT sequence of the SCALE 6.1 package. The evolution of the delayed neutron fraction uncertainty over burn-up is analysed without and with the consideration of delayed nu-bar uncertainties. Moreover, the main contributors to the result uncertainty are determined. In all cases, the delayed nu-bar uncertainties increase the delayed neutron fraction uncertainty. Depending on the fuel composition, the delayed nu-bar values of uranium and plutonium in fact give the main contributions to the delayed neutron fraction uncertainty for the LWR fuel assemblies. For the SFR case, the uncertainty of the scattering cross section of U-238 is the main contributor.

Boundary states at reflective moving boundaries

NASA Astrophysics Data System (ADS)

Acosta Minoli, Cesar A.; Kopriva, David A.

2012-06-01

We derive and evaluate boundary states for Maxwell's equations, the linear, and the nonlinear Euler gas-dynamics equations to compute wave reflection from moving boundaries. In this study we use a Discontinuous Galerkin Spectral Element method (DGSEM) with Arbitrary Lagrangian-Eulerian (ALE) mapping for the spatial approximation, but the boundary states can be used with other methods, like finite volume schemes. We present four studies using Maxwell's equations, one for the linear Euler equations, and one more for the nonlinear Euler equations. These are: reflection of light from a plane mirror moving at constant velocity, reflection of light from a moving cylinder, reflection of light from a vibrating mirror, reflection of sound from a plane wall and dipole sound generation by an oscillating cylinder in an inviscid flow. The studies show that the boundary states preserve spectral convergence in the solution and in derived quantities like divergence and vorticity.

Association Between Facial Rejuvenation and Observer Ratings of Youth, Attractiveness, Success, and Health

PubMed Central

Bater, Kristin L.; Papel, Ira D.; Kontis, Theda C.; Byrne, Patrick J.; Boahene, Kofi D. O.; Nellis, Jason C.; Ishii, Masaru

2017-01-01

Importance Surgical procedures for the aging face—including face-lift, blepharoplasty, and brow-lift—consistently rank among the most popular cosmetic services sought by patients. Although these surgical procedures are broadly classified as procedures that restore a youthful appearance, they may improve societal perceptions of attractiveness, success, and health, conferring an even larger social benefit than just restoring a youthful appearance to the face. Objectives To determine if face-lift and upper facial rejuvenation surgery improve observer ratings of age, attractiveness, success, and health and to quantify the effect of facial rejuvenation surgery on each individual domain. Design, Setting, and Participants A randomized clinical experiment was performed from August 30 to September 18, 2016, using web-based surveys featuring photographs of patients before and after facial rejuvenation surgery. Observers were randomly shown independent images of the 12 patients; within a given survey, observers saw either the preoperative or postoperative photograph of each patient to reduce the possibility of priming. Observers evaluated patient age using a slider bar ranging from 30 to 80 years that could be moved up or down in 1-year increments, and they ranked perceived attractiveness, success, and health using a 100-point visual analog scale. The bar on the 100-point scale began at 50; moving the bar to the right corresponded to a more positive rating in these measures and moving the bar to the left, a more negative rating. Main Outcomes and Measures A multivariate mixed-effects regression model was used to understand the effect of face-lift and upper facial rejuvenation surgery on observer perceptions while accounting for individual biases of the participants. Ordinal rank change was calculated to understand the clinical effect size of changes across the various domains after surgery. Results A total of 504 participants (333 women, 165 men, and 6 unspecified; mean age, 29 [range, 18-70] years) successfully completed the survey. A multivariate mixed-effects regression model revealed a statistically significant change in age (–4.61 years; 95% CI, –4.97 to –4.25) and attractiveness (6.72; 95% CI, 5.96-7.47) following facial rejuvenation surgery. Observer-perceived success (3.85; 95% CI, 3.12-4.57) and health (7.65; 95% CI; 6.87-8.42) also increased significantly as a result of facial rejuvenation surgery. Conclusions and Relevance The data presented in this study demonstrate that patients are perceived as younger and more attractive by the casual observer after undergoing face-lift and upper facial rejuvenation surgery. These procedures also improved ratings of perceived success and health in our patient population. These findings suggest that facial rejuvenation surgery conveys an even larger societal benefit than merely restoring a youthful appearance to the face. Level of Evidence NA. PMID:28448667

Swarmathon 2017

NASA Image and Video Library

2017-04-19

At the Kennedy Space Center Visitor Complex, students monitor progress as their Swarmie robots as they search for "resources." The goal is for the robots to pick up cubes with AprilTags, which are similar to bar codes. The Swarmies then move the cubes to a white square in the center of the completion arena. The small, four-wheeled robots are designed to effectively and efficiently locate hidden resources while astronauts explore distant destinations such as the moon or Mars.

Measurement and simulation of deformation and stresses in steel casting

NASA Astrophysics Data System (ADS)

Galles, D.; Monroe, C. A.; Beckermann, C.

2012-07-01

Experiments are conducted to measure displacements and forces during casting of a steel bar in a sand mold. In some experiments the bar is allowed to contract freely, while in others the bar is manually strained using embedded rods connected to a frame. Solidification and cooling of the experimental castings are simulated using a commercial code, and good agreement between measured and predicted temperatures is obtained. The deformations and stresses in the experiments are simulated using an elasto-viscoplastic finite-element model. The high temperature mechanical properties are estimated from data available in the literature. The mush is modeled using porous metal plasticity theory, where the coherency and coalescence solid fraction are taken into account. Good agreement is obtained between measured and predicted displacements and forces. The results shed considerable light on the modeling of stresses in steel casting and help in developing more accurate models for predicting hot tears and casting distortions.

Modeling And Simulation Of Bar Code Scanners Using Computer Aided Design Software

NASA Astrophysics Data System (ADS)

Hellekson, Ron; Campbell, Scott

1988-06-01

Many optical systems have demanding requirements to package the system in a small 3 dimensional space. The use of computer graphic tools can be a tremendous aid to the designer in analyzing the optical problems created by smaller and less costly systems. The Spectra Physics grocery store bar code scanner employs an especially complex 3 dimensional scan pattern to read bar code labels. By using a specially written program which interfaces with a computer aided design system, we have simulated many of the functions of this complex optical system. In this paper we will illustrate how a recent version of the scanner has been designed. We will discuss the use of computer graphics in the design process including interactive tweaking of the scan pattern, analysis of collected light, analysis of the scan pattern density, and analysis of the manufacturing tolerances used to build the scanner.

Drinking Context and Drinking Problems Among Black, White, and Hispanic Men and Women in the 1984, 1995, and 2005 U.S. National Alcohol Surveys*

PubMed Central

Nyaronga, Dan; Greenfield, Thomas K.; McDaniel, Patricia A.

2009-01-01

Objective: The purpose of this study was to investigate the preferred drinking contexts of different gender and ethnic groups (white, black, and Hispanic men and women), by examining where these groups do most of their drinking and to what extent drinking contexts preferences are associated with certain drinking-related consequences. Method: The study used data from the 1984, 1995, and 2005 U.S. National Alcohol Surveys. Among current drinkers, cluster analyses of volume drunk in six contexts (restaurants, bars, others' parties, or when spending a quiet evening at home, having friends drop over at home, and hanging out in public places) were used to classify individuals by their drinking context preferences in each gender by ethnicity subgroup. Results: We identified three highly similar drinking context-preference clusters within each of the six subgroups: (1) bar-plus group (did most drinking in bars, plus much in other venues), (2) home group (did most drinking at home, and a fair amount elsewhere), and (3) light group (drank almost nothing quietly at home and also less in other settings than the other two clusters). For a number of ethnic-by-gender groups, context preference group assignment predicted drinking-related problems, over and above general drinking patterns. For example, for all groups, the bar-plus preference group relative to the light group showed higher risk of arguments, fighting, and drunk driving, after taking into account the volume consumed, frequency of heavy drinking, age, and year of survey. Conclusions: Examining individuals' preferred drinking contexts may provide important information to augment overall drinking patterns in risk and prevention studies. PMID:19118387

Hubble Spots a Barred Lynx Spiral

NASA Image and Video Library

2017-12-08

Discovered by British astronomer William Herschel over 200 years ago, NGC 2500 lies about 30 million light-years away in the northern constellation of Lynx. As this NASA/ESA Hubble Space Telescope image shows, NGC 2500 is a particular kind of spiral galaxy known as a barred spiral, its wispy arms swirling out from a bright, elongated core. Barred spirals are actually more common than was once thought. Around two-thirds of all spiral galaxies — including the Milky Way — exhibit these straight bars cutting through their centers. These cosmic structures act as glowing nurseries for newborn stars, and funnel material towards the active core of a galaxy. NGC 2500 is still actively forming new stars, although this process appears to be occurring very unevenly. The upper half of the galaxy — where the spiral arms are slightly better defined — hosts many more star-forming regions than the lower half, as indicated by the bright, dotted islands of light. There is another similarity between NGC 2500 and our home galaxy. Together with Andromeda, Triangulum and many smaller natural satellites, the Milky Way is part of the Local Group of galaxies, a gathering of over 50 galaxies all loosely held together by gravity. NGC 2500 forms a similar group with some of its nearby neighbors, including NGC 2541, NGC 2552, NGC 2537 and the bright, Andromeda-like spiral NGC 2481 (known collectively as the NGC 2841 group). Image Credit: ESA/Hubble/NASA NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Two-dimensional receptive-field organization in striate cortical neurons of the cat.

PubMed

Sun, M; Bonds, A B

1994-01-01

The two-dimensional organization of receptive fields (RFs) of 44 cells in the cat visual cortex and four cells from the cat LGN was measured by stimulation with either dots or bars of light. The light bars were presented in different positions and orientations centered on the RFs. The RFs found were arbitrarily divided into four general types: Punctate, resembling DOG filters (11%); those resembling Gabor filters (9%); elongate (36%); and multipeaked-type (44%). Elongate RFs, usually found in simple cells, could show more than one excitatory band or bifurcation of excitatory regions. Although regions inhibitory to a given stimulus transition (e.g. ON) often coincided with regions excitatory to the opposite transition (e.g. OFF), this was by no means the rule. Measurements were highly repeatable and stable over periods of at least 1 h. A comparison between measurements made with dots and with bars showed reasonable matches in about 40% of the cases. In general, bar-based measurements revealed larger RFs with more structure, especially with respect to inhibitory regions. Inactivation of lower cortical layers (V-VI) by local GABA injection was found to reduce sharpness of detail and to increase both receptive-field size and noise in upper layer cells, suggesting vertically organized RF mechanisms. Across the population, some cells bore close resemblance to theoretically proposed filters, while others had a complexity that was clearly not generalizable, to the extent that they seemed more suited to detection of specific structures. We would speculate that the broadly varying forms of cat cortical receptive fields result from developmental processes akin to those that form ocular-dominance columns, but on a smaller scale.

A Modified Split Hopkinson Pressure Bar Approach for Mimicking Dynamic Oscillatory Stress Fluctuations During Earthquake Rupture

NASA Astrophysics Data System (ADS)

Braunagel, M. J.; Griffith, W. A.

2017-12-01

Past experimental work has demonstrated that rock failure at high strain rates occurs by fragmentation rather than discrete fracture and is accompanied by a dramatic increase in rock strength. However, these observations are difficult to reconcile with the assertion that pulverized rocks in fault zones are the product of impulsive stresses during the passage of earthquake ruptures, as the distance from the principal slip zones of some pulverized rock is too great to exceed fragmentation transition. One potential explanation to this paradox that has been suggested is that repeated loading over the course of multiple earthquake ruptures may gradually reduce the pulverization threshold, in terms of both strain rate and strength. We propose that oscillatory loading during a single earthquake rupture may further lower these pulverization thresholds, and that traditional dynamic experimental approaches, such as the Split Hopkinson Pressure Bar (SHPB) wherein load is applied as a single, smooth, sinusoidal compressive wave, may not reflect natural loading conditions. To investigate the effects of oscillatory compressive loading expected during earthquake rupture propagation, we develop a controlled cyclic loading model on a SHPB apparatus utilizing two striker bars connected by an elastic spring. Unlike traditional SHPB experiments that utilize a gas gun to fire a projectile bar and generate a single compressive wave on impact with the incident bar, our modified striker bar assembly oscillates while moving down the gun barrel and generates two separate compressive pulses separated by a lag time. By modeling the modified assembly as a mass-spring-mass assembly accelerating due to the force of the released gas, we can predict the compression time of the spring upon impact and therefore the time delay between the generation of the first and second compressive waves. This allows us to predictably control load cycles with durations of only a few hundred microseconds. Initial experimental results demonstrate that fragmentation of Westerly Granite samples occurs at lower stresses and strain rates than those expected from traditional SHPB experiments.

Dissecting a Light Echo

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on image for audio animation

This animation illustrates how a light echo works, and how an optical illusion of material moving outward is created.

A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one.

The animation starts by showing the explosion of a star, which results in a flash of light that moves outward in all directions. The direction of our line of sight from Earth is indicated by the blue arrow.

When the light flash reaches surrounding dust, shown here as three dark clouds, the dust is heated up, creating infrared light that begins to travel toward Earth (indicated by the red arrows). Dust closest to the explosion lights up first, while the explosion's shock wave takes longer to reach more distant material. This results in light from different parts of the cloud reaching Earth at different times, creating the illusion of motion over time.

As the animation shows, the inclination of the cloud toward our line of sight can result in the material seeming to move both away from and toward the central star.

River channel bars and dunes - Theory of kinematic waves

USGS Publications Warehouse

Langbein, Walter Basil; Leopold, Luna Bergere

1968-01-01

A kinematic wave is a grouping cf moving objects in zones along a flow path and through which the objects pass. These concentrations may be characterized by a simple relation between the speed of the moving objects and their spacing as a result of interaction between them.Vehicular traffic has long been known to have such properties. Data are introduced to show that beads carried by flowing water in a narrow flume behave in an analogous way. The flux or transport of objects in a single lane of traffic is greatest when the objects are spaced about two diameters apart; beads in a single-lane flume as well as highway traffic conform to this property.By considering the sand in a pipe or flume to a depth affected by dune movement, it is shown that flux-concentration curves similar to the previously known cases can be constructed from experimental data. From the kinematic point of view, concentration of particles in dunes and other wave bed forms results when particles in transport become more numerous or closely spaced and interact to reduce the effectiveness of the ambient water to move them.Field observations over a 5-year period are reported in which individual rocks were painted for identification and placed at various spacings on the bed of ephemeral stream in New Mexico, to study the effect of storm flows on rock movement. The data on about 14,000 rocks so observed show the effect of variable spacing which is quantitatively as well as qualitatively comparable to the spacing effect on small glass beads in a flume. Dunes and gravel bars may be considered kinematic waves caused by particle interaction, and certain of their properties can be related to the characteristics of the flux-concentration curve.

In-situ measurement of concentrated solar flux and distribution at the aperture of a central solar receiver

NASA Astrophysics Data System (ADS)

Ferriere, Alain; Volut, Mikael; Perez, Antoine; Volut, Yann

2016-05-01

A flux mapping system has been designed, implemented and experimented at the top of the Themis solar tower in France. This system features a moving bar associated to a CCD video camera and a flux gauge mounted onto the bar used as reference measurement for calibration purpose. Images and flux signal are acquired separately. The paper describes the equipment and focus on the data processing to issue the distribution of flux density and concentration at the aperture of the solar receiver. Finally, the solar power entering into the receiver is estimated by integration of flux density. The processing is largely automated in the form of a dedicated software with fast execution. A special attention is paid to the accuracy of the results, to the robustness of the algorithm and to the velocity of the processing.

Morphodynamic modeling of a large inside sandbar and its dextral morphology in a convergent estuary: Qiantang Estuary, China

NASA Astrophysics Data System (ADS)

Xie, Dongfeng; Gao, Shu; Wang, Zheng Bing; Pan, Cunhong; Wu, Xiuguang; Wang, Qiushun

2017-08-01

We investigate the evolution of a large-scale sand body, a unique type of sandbars in a convergent estuary. Specifically, we analyze and simulate the sand deposition system (defined as an inside bar) in the Qiantang Estuary (QE) in China. The deposit is 130 km long and up to 10 m thick and is characterized by a dextral morphology in the lower QE. Numerical simulation is carried out using an idealized horizontal 2-D morphodynamic model mimicking the present QE settings. Our results indicate that the morphological evolution is controlled by the combination of river discharge and tides. The seasonal and interannual cycles of river discharges play a major role on the inside bar evolution. The bar is eroding during high river discharge periods, but accretion prevails during low river discharge periods. Meanwhile, the highest part of the sand body can move downstream or upstream by several kilometers, modifying the seasonal sediment exchange patterns. We also show that the Coriolis force plays an important role on the dextral morphology patterns in wide, convergent estuaries. It induces a significant lateral water level difference and a large-scale gyre of residual sediment transport. Subsequently, the seaward tail of the inside bar shifts southward to help create a condition for the development of tidal flats in the lower reach of the estuary. The lateral bed level differences induced by Coriolis force are up to several meters. Coriolis effects also modify the behavior of flood and ebb tidal channels.

Comparisons of MOVES Light-duty Gasoline NOx Emission Rates with Real-world Measurements

NASA Astrophysics Data System (ADS)

Choi, D.; Sonntag, D.; Warila, J.

2017-12-01

Recent studies have shown differences between air quality model estimates and monitored values for nitrogen oxides. Several studies have suggested that the discrepancy between monitored and modeled values is due to an overestimation of NOx from mobile sources in EPA's emission inventory, particularly for light-duty gasoline vehicles. EPA's MOtor Vehicle Emission Simulator (MOVES) is an emission modeling system that estimates emissions for cars, trucks and other mobile sources at the national, county, and project level for criteria pollutants, greenhouse gases, and air toxics. Studies that directly measure vehicle emissions provide useful data for evaluating MOVES when the measurement conditions are properly accounted for in modeling. In this presentation, we show comparisons of MOVES2014 to thousands of real-world NOx emissions measurements from individual light-duty gasoline vehicles. The comparison studies include in-use vehicle emissions tests conducted on chassis dynamometer tests in support of Denver, Colorado's Vehicle Inspection & Maintenance Program and remote sensing data collected using road-side instruments in multiple locations and calendar years in the United States. In addition, we conduct comparisons of MOVES predictions to fleet-wide emissions measured from tunnels. We also present details on the methodology used to conduct the MOVES model runs in comparing to the independent data.

Sedimentology of Upper Cretaceous Coffee sands in north-central Mississippi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, E.J.

1984-09-01

The Upper Cretaceous Coffee Group within the Desha basin of Mississippi is composed of two major lithologies, a light to dark marlstone and a series of white, fine to medium-grained siltstones and sandstones. The two source areas for the sands are the Sharkey platform to the south and the southern Appalachians. The presence of hydrocarbons has been described at the outcrop and in subsurface cuttings and cores. Depositional environments in the shallow shelf consist of lagoons, barrier island bars, offshore bars, and surge channel deposits. Southwest regional dip of approximately 40 ft/mi (8 m/km) is reflected on all Upper Cretaceousmore » horizons.« less

Left right asymmetry of nuclear shadowing in charged current DIS

NASA Astrophysics Data System (ADS)

Fiore, R.; Zoller, V. R.

2006-01-01

We study the shadowing effect in highly asymmetric diffractive interactions of left- and right-handed W-bosons with atomic nuclei. The target nucleus is found to be quite transparent for the charmed-strange Fock component of the light-cone W+ in the helicity state λ = + 1 and rather opaque for the csbar dipole with λ = - 1. The shadowing correction to the structure function ΔxF3 = x F3νN - x F3νbarN extracted from νFe and νbar Fe data is shown to make up about 20% in the kinematical range of CCFR/NuTeV.

Quantitative NO-LIF imaging in high-pressure flames

NASA Astrophysics Data System (ADS)

Bessler, W. G.; Schulz, C.; Lee, T.; Shin, D.-I.; Hofmann, M.; Jeffries, J. B.; Wolfrum, J.; Hanson, R. K.

2002-07-01

Planar laser-induced fluorescence (PLIF) images of NO concentration are reported in premixed laminar flames from 1-60 bar exciting the A-X(0,0) band. The influence of O2 interference and gas composition, the variation with local temperature, and the effect of laser and signal attenuation by UV light absorption are investigated. Despite choosing a NO excitation and detection scheme with minimum O2-LIF contribution, this interference produces errors of up to 25% in a slightly lean 60 bar flame. The overall dependence of the inferred NO number density with temperature in the relevant (1200-2500 K) range is low (<±15%) because different effects cancel. The attenuation of laser and signal light by combustion products CO2 and H2O is frequently neglected, yet such absorption yields errors of up to 40% in our experiment despite the small scale (8 mm flame diameter). Understanding the dynamic range for each of these corrections provides guidance to minimize errors in single shot imaging experiments at high pressure.

Unique bar-like sulfur-doped C3N4/TiO2 nanocomposite: Excellent visible light driven photocatalytic activity and mechanism study

NASA Astrophysics Data System (ADS)

Zhao, Yu; Xu, Shiping; Sun, Xiang; Xu, Xing; Gao, Baoyu

2018-04-01

In this work, a nanocomposite of TiO2 nanoparticles coupled with sulfur-doped C3N4 (S-C3N4) laminated layer was successfully fabricated using a facile impregnation method and the nanocomposite exhibited superior photocatalytic activity in pollutant removal under visible light irradiation, compared to bare TiO2, g-C3N4 and binary C3N4-TiO2 nanocomposite. The enhanced photocatalytic activity was benefited from the efficient migration and transformation of electron-hole (e--h+) pairs, improved visible light absorption capability, and relatively large specific surface area induce by sulfur doping. Interestingly, the introduction of sulfur changes regulated the morphology of g-C3N4 leading to the formation of ultrathin g-C3N4 layer nanosheet assemblies and unique bar-like g-C3N4/TiO2 nanocomposite, which is beneficial for the outstanding performance of the product. In addition, trapping experiment was carried out to identify the main active species in the photocatalytic reaction over the S-C3N4/TiO2 photocatalyst, and functional mechanism of the composite was proposed. This work may provide new ideas for the fabrication and utilization of highly efficient photocatalyst with excellent visible light response in environmental purification applications.

111. DETAIL OF FILTER DISCS ON DENVER FILTER IN CO91107. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

111. DETAIL OF FILTER DISCS ON DENVER FILTER IN CO-91-107. AS DISCS SLOWLY ROTATE, VACUUM INSIDE DISCS ATTRACT SLURRY IN THE SUMP AND DEWATERS CONCENTRATE AS DISCS MOVE THROUGH AIR. FURTHER ROTATION PASSES A BAR TO SCRAPE OFF DRIED METAL CONCENTRATE, ASSISTED BY BLASTS OF COMPRESSED AIR. METAL CONCENTRATE READY FOR SHIPMENT TO SMELTER FALLS INTO BIN BELOW. EIMCO FILTERS OPERATE SIMILARLY. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

Determining biological tissue optical properties via integrating sphere spatial measurements

DOEpatents

Baba, Justin S [Knoxville, TN; Letzen, Brian S [Coral Springs, FL

2011-01-11

An optical sample is mounted on a spatial-acquisition apparatus that is placed in or on an enclosure. An incident beam is irradiated on a surface of the sample and the specular reflection is allowed to escape from the enclosure through an opening. The spatial-acquisition apparatus is provided with a light-occluding slider that moves in front of the sample to block portions of diffuse scattering from the sample. As the light-occluding slider moves across the front of the sample, diffuse light scattered into the area of the backside of the light-occluding slider is absorbed by back side surface of the light-occluding slider. By measuring a baseline diffuse reflectance without a light-occluding slider and subtracting measured diffuse reflectance with a light-occluding slider therefrom, diffuse reflectance for the area blocked by the light-occluding slider can be calculated.

Supersymmetric Properties of Hadron Physics from Light-Front Holography and Superconformal Algebra and other Advances in Light-Front QCD

NASA Astrophysics Data System (ADS)

Brodsky, Stanley J.

2018-05-01

Light-front holography, together with superconformal algebra, have provided new insights into the physics of color confinement and the spectroscopy and dynamics of hadrons. As shown by de Alfaro, Fubini and Furlan, a mass scale can appear in the equations of motion without affecting the conformal invariance of the action if one adds a term to the Hamiltonian proportional to the dilatation operator or the special conformal operator. If one applies the procedure of de Alfaro et al. to the frame-independent light-front Hamiltonian, it leads uniquely to a confining q \\bar{q} potential κ ^4 ζ ^2, where ζ ^2 is the light-front radial variable related in momentum space to the q \\bar{q} invariant mass. The same result, including spin terms, is obtained using light-front holography—the duality between the front form and AdS_5, the space of isometries of the conformal group—if one modifies the action of AdS_5 by the dilaton e^{κ ^2 z^2} in the fifth dimension z. When one generalizes this procedure using superconformal algebra, the resulting light-front eigensolutions lead to a a unified Regge spectroscopy of meson, baryon, and tetraquarks, including supersymmetric relations between their masses and their wavefunctions. One also predicts hadronic light-front wavefunctions and observables such as structure functions, transverse momentum distributions, and the distribution amplitudes. The mass scale κ underlying confinement and hadron masses can be connected to the parameter Λ_{\\overline{MS}} in the QCD running coupling by matching the nonperturbative dynamics to the perturbative QCD regime. The result is an effective coupling α _s(Q^2) defined at all momenta. The matching of the high and low momentum transfer regimes determines a scale Q_0 which sets the interface between perturbative and nonperturbative hadron dynamics. I also discuss a number of applications of light-front phenomenology.

Error analysis of mechanical system and wavelength calibration of monochromator

NASA Astrophysics Data System (ADS)

Zhang, Fudong; Chen, Chen; Liu, Jie; Wang, Zhihong

2018-02-01

This study focuses on improving the accuracy of a grating monochromator on the basis of the grating diffraction equation in combination with an analysis of the mechanical transmission relationship between the grating, the sine bar, and the screw of the scanning mechanism. First, the relationship between the mechanical error in the monochromator with the sine drive and the wavelength error is analyzed. Second, a mathematical model of the wavelength error and mechanical error is developed, and an accurate wavelength calibration method based on the sine bar's length adjustment and error compensation is proposed. Based on the mathematical model and calibration method, experiments using a standard light source with known spectral lines and a pre-adjusted sine bar length are conducted. The model parameter equations are solved, and subsequent parameter optimization simulations are performed to determine the optimal length ratio. Lastly, the length of the sine bar is adjusted. The experimental results indicate that the wavelength accuracy is ±0.3 nm, which is better than the original accuracy of ±2.6 nm. The results confirm the validity of the error analysis of the mechanical system of the monochromator as well as the validity of the calibration method.

HUBBLE CAPTURES THE HEART OF STAR BIRTH

NASA Technical Reports Server (NTRS)

2002-01-01

NASA Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) has captured a flurry of star birth near the heart of the barred spiral galaxy NGC 1808. On the left are two images, one superimposed over the other. The black-and-white picture is a ground-based view of the entire galaxy. The color inset image, taken with the Hubble telescope's Wide Field and Planetary Camera 2 (WFPC2), provides a close-up view of the galaxy's center, the hotbed of vigorous star formation. The ground-based image shows that the galaxy has an unusual, warped shape. Most spiral galaxies are flat disks, but this one has curls of dust and gas at its outer spiral arms (upper right-hand corner and lower left-hand corner). This peculiar shape is evidence that NGC 1808 may have had a close interaction with another nearby galaxy, NGC 1792, which is not in the picture Such an interaction could have hurled gas towards the nucleus of NGC 1808, triggering the exceptionally high rate of star birth seen in the WFPC2 inset image. The WFPC2 inset picture is a composite of images using colored filters that isolate red and infrared light as well as light from glowing hydrogen. The red and infrared light (seen as yellow) highlight older stars, while hydrogen (seen as blue) reveals areas of star birth. Colors were assigned to this false-color image to emphasize the vigorous star formation taking place around the galaxy's center. NGC 1808 is called a barred spiral galaxy because of the straight lines of star formation on both sides of the bright nucleus. This star formation may have been triggered by the rotation of the bar, or by matter which is streaming along the bar towards the central region (and feeding the star burst). Filaments of dust are being ejected from the core into a faint halo of stars surrounding the galaxy's disk (towards the upper left corner) by massive stars that have exploded as supernovae in the star burst region. The portion of the galaxy seen in this 'wide-field' image is about 35,000 light-years across. The right-hand image, taken by WFPC2, provides a closer look at the flurry of star birth at the galaxy's core. The star clusters (blue) can be seen (and many more are likely obscured) amid thick lanes of gas and dust. This image shows that stars are often born in compact clusters within star bursts, and that dense gas and dust heavily obscures the star burst region. The brightest knot of star birth seen here is probably a giant cluster of stars, about 100 light-years in diameter, at the very center of the galaxy. The other star clusters are about 10 to 50 light-years in diameter. The entire star burst region shown here is about 3,000 light-years across. This galaxy is about 40 million light-years away in the southern constellation Columba. The observation was taken Aug. 14, 1997, and was the last of 13 Hubble Space Telescope amateur programs. Credits: Jim Flood, an amateur astronomer affiliated with Sperry Observatory at Union College in New Jersey, and Max Mutchler, a member of the Space Telescope Science Institute staff who volunteered to work with Jim.

An Enduring Rapidly Moving Storm as a Guide to Saturn's Equatorial Jet's Complex Structure

NASA Technical Reports Server (NTRS)

Sanchez-Lavega, A.; Garcia-Melendo, E.; Perez-Hoyos, S.; Hueso, R.; Wong, M. H.; Simon, A.; Sanz-Requena, J. F.; Antunano, A.; Barrado-Izagirre, N.; Garate-Lopez, I.;

Chloroplasts do not have a polarity for light-induced accumulation movement.

PubMed

Tsuboi, Hidenori; Yamashita, Hiroko; Wada, Masamitsu

2009-01-01

Chloroplast photorelocation movement in green plants is generally mediated by blue light. However, in cryptogam plants, including ferns, mosses, and algae, both red light and blue light are effective. Although the photoreceptors required for this phenomenon have been identified, the mechanisms underlying this movement response are not yet known. In order to analyze this response in more detail, chloroplast movement was induced in dark-adapted Adiantum capillus-veneris gametophyte cells by partial cell irradiation with a microbeam of red and/or blue light. In each case, chloroplasts were found to move toward the microbeam-irradiated area. A second microbeam was also applied to the cell at a separate location before the chloroplasts had reached the destination of the first microbeam. Under these conditions, chloroplasts were found to change their direction of movement without turning and move toward the second microbeam-irradiated area after a lag time of a few minutes. These findings indicate that chloroplasts can move in any direction and do not exhibit a polarity for chloroplast accumulation movement. This phenomenon was analyzed in detail in Adiantum and subsequently confirmed in Arabidopsis thaliana palisade cells. Interestingly, the lag time for direction change toward the second microbeam in Adiantum was longer in the red light than in the blue light. However, the reason for this discrepancy is not yet understood.

Evaluation of video detection systems, volume 2 : effects of illumination conditions in the performance of video detection systems.

DOT National Transportation Integrated Search

2009-05-01

The evaluation of three Video Detection Systems (VDS) at an instrumented signalized intersection in Rantoul : Illinois, at both stop bar and advance detection zones, was performed under a wide range of lighting and : weather conditions. The evaluated...

Polarization methods for diode laser excitation of solid state lasers

DOEpatents

Holtom, Gary R.

2008-11-25

A mode-locked laser employs a coupled-polarization scheme for efficient longitudinal pumping by reshaped laser diode bars. One or more dielectric polarizers are configured to reflect a pumping wavelength having a first polarization and to reflect a lasing wavelength having a second polarization. A Yb-doped gain medium can be used that absorbs light having a first polarization and emits light having a second polarization. Using such pumping with laser cavity dispersion control, pulse durations of less than 100 fs can be achieved.

Learning about Lasers

ERIC Educational Resources Information Center

Roberts, Larry

2011-01-01

The word laser is an acronym. It stands for Light Amplification by Stimulated Emission of Radiation. Lasers, invented in 1958, are used to cut and fuse materials, accurately survey long distances, communicate across fiber-optic phone lines, produce 3D pictures, make special effects, help navigation, and read bar codes for cash registers. A laser…

Cylindrical microlens with an internally reflecting surface and a method of fabrication

DOEpatents

Beach, Raymond J.; Freitas, Barry L.

2004-03-23

A fast (high numerical aperture) cylindrical microlens, which includes an internally reflective surface, that functions to deviate the direction of the light that enters the lens from its original propagation direction is employed in optically conditioning laser diodes, laser diode arrays and laser diode bars.

A Cylindrical Microlens With An Internally Reflective Surface And A Method Of Fabrication

DOEpatents

Beach, Raymond J.; Freitas, Barry L.

2005-09-27

A fast (high numerical aperture) cylindrical microlens, which includes an internally reflective surface, that functions to deviate the direction of the light that enters the lens from its original propagation direction is employed in optically conditioning laser diodes, laser diode arrays and laser diode bars.

Galaxy NGC5398

NASA Image and Video Library

2003-07-25

This is an ultraviolet color image of the galaxy NGC5398 taken by NASA Galaxy Evolution Explorer on June 7, 2003. NGC5398 is a barred spiral galaxy located 60 million light-years from Earth. The star formation is concentrated in the two bright regions of the image. http://photojournal.jpl.nasa.gov/catalog/PIA04633

Electromagnetic Gun With Commutated Coils

NASA Technical Reports Server (NTRS)

Elliott, David G.

1991-01-01

Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.

Repair, Evaluation, Maintenance, and Rehabilitation Research Program. Underwater Repair of Concrete Damaged by Abrasion-Erosion

DTIC Science & Technology

1991-12-01

and compatible placement tech- niques that can ensure successful and cost effective repairs of scour holes of different sizes and depths under water...bridge foundation in Japan. The valve was attached to the bottom of a pump line and was moved to cast concrete in successive layers at several locations...surfaces, reinforc- ing steel, and dowel bars in order to ensure successful and durable repairs. Thi. is ( specizlly important since it is not practical to

Environmental Mapping by a HERO-1 Robot Using Sonar and a Laser Barcode Scanner.

DTIC Science & Technology

1983-12-01

can be labled with an x-y type coordinate grid allowing the rover to directly read * its location as it moves along. A different approach is to...uses a two-dimensional grid of two character barcodes as reference objects. Since bar codes are designed to be read in either of two orientations (top...Processing Laboratory at AFIT (see Appendix B for listing). Navigation grid codes consist of two digits running consecutively from 00 to FF, yielding 256

Measurement of the Effective Weak Mixing Angle in $$p\\bar{p}\\rightarrow Z/\\gamma^* \\rightarrow \\ell^+\\ell^-$$ Events

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abazov, Victor Mukhamedovich; et al.

2017-10-11

We present a measurement of the effective weak mixing angle parametermore » $$\\sin^2\\theta_\\text{eff}^{\\ell}$$, in $$p\\bar{p}\\rightarrow Z/\\gamma^* \\rightarrow \\mu^+\\mu^-$$ events at a center of mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider and corresponding to 8.6 fb$$^{-1}$$ of integrated luminosity. The measured value of $$\\sin^2\\theta_\\text{eff}^{\\ell}[\\mu\\mu]=0.23016 \\pm 0.00064$$ is further combined with the result from the D0 measurement in $$p\\bar{p}\\rightarrow Z/\\gamma^{*}\\rightarrow e^{+} e^{-}$$ events, resulting in $$\\sin^2\\theta_\\text{eff}^{\\ell} [\\text{comb.}]=0.23095 \\pm 0.00040$$. This combined result is the most precise measurement from a single experiment at a hadron collider and is the most precise determination using the coupling of the $$Z/\\gamma^*$$ to light quarks.« less

Standalone BISON Fuel Performance Results for Watts Bar Unit 1, Cycles 1-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clarno, Kevin T.; Pawlowski, Roger; Stimpson, Shane

2016-03-07

The Consortium for Advanced Simulation of Light Water Reactors (CASL) is moving forward with more complex multiphysics simulations and increased focus on incorporating fuel performance analysis methods. The coupled neutronics/thermal-hydraulics capabilities within the Virtual Environment for Reactor Applications Core Simulator (VERA-CS) have become relatively stable, and major advances have been made in analysis efforts, including the simulation of twelve cycles of Watts Bar Nuclear Unit 1 (WBN1) operation. While this is a major achievement, the VERA-CS approaches for treating fuel pin heat transfer have well-known limitations that could be eliminated through better integration with the BISON fuel performance code. Severalmore » approaches are being implemented to consider fuel performance, including a more direct multiway coupling with Tiamat, as well as a more loosely coupled one-way approach with standalone BISON cases. Fuel performance typically undergoes an independent analysis using a standalone fuel performance code with manually specified input defined from an independent core simulator solution or set of assumptions. This report summarizes the improvements made since the initial milestone to execute BISON from VERA-CS output. Many of these improvements were prompted through tighter collaboration with the BISON development team at Idaho National Laboratory (INL). A brief description of WBN1 and some of the VERA-CS data used to simulate it are presented. Data from a small mesh sensitivity study are shown, which helps justify the mesh parameters used in this work. The multi-cycle results are presented, followed by the results for the first three cycles of WBN1 operation, particularly the parameters of interest to pellet-clad interaction (PCI) screening (fuel-clad gap closure, maximum centerline fuel temperature, maximum/minimum clad hoop stress, and cumulative damage index). Once the mechanics of this capability are functioning, future work will target cycles with known or suspected PCI failures to determine how well they can be estimated.« less

Revisiting the Tale of Hercules: How Stars Orbiting the Lagrange Points Visit the Sun

NASA Astrophysics Data System (ADS)

Pérez-Villegas, Angeles; Portail, Matthieu; Wegg, Christopher; Gerhard, Ortwin

2017-05-01

We propose a novel explanation for the Hercules stream consistent with recent measurements of the extent and pattern speed of the Galactic bar. We have adapted a made-to-measure dynamical model tailored for the Milky Way to investigate the kinematics of the solar neighborhood (SNd). The model matches the 3D density of the red clump giant stars (RCGs) in the bulge and bar as well as stellar kinematics in the inner Galaxy, with a pattern speed of 39 km s-1 kpc-1. Cross-matching this model with the Gaia DR1 TGAS data combined with RAVE and LAMOST radial velocities, we find that the model naturally predicts a bimodality in the U-V-velocity distribution for nearby stars which is in good agreement with the Hercules stream. In the model, the Hercules stream is made of stars orbiting the Lagrange points of the bar which move outward from the bar’s corotation radius to visit the SNd. While the model is not yet a quantitative fit of the velocity distribution, the new picture naturally predicts that the Hercules stream is more prominent inward from the Sun and nearly absent only a few 100 pc outward of the Sun, and plausibly explains that Hercules is prominent in old and metal-rich stars.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van den Bergh, Sidney, E-mail: sidney.vandenbergh@nrc.gc.ca

Lenticular galaxies with M{sub B} < -21.5 are almost exclusively unbarred, whereas both barred and unbarred objects occur at fainter luminosity levels. This effect is observed both for objects classified in blue light, and for those that were classified in the infrared. This result suggests that the most luminous (massive) S0 galaxies find it difficult to form bars. As a result, the mean luminosity of unbarred lenticular galaxies in both B and IR light is observed to be {approx}0.4 mag brighter than that of barred lenticulars. A small contribution to the observed luminosity difference that is found between SA0 andmore » SB0 galaxies may also be due to the fact that there is an asymmetry between the effects of small classification errors on SA0 and SB0 galaxies. An elliptical (E) galaxy might be misclassified as a lenticular (S0) or an S0 as an E. However, an E will never be misclassified as an SB0, nor will an SB0 ever be called an E. This asymmetry is important because E galaxies are typically twice as luminous as S0 galaxies. The present results suggest that the evolution of luminous lenticular galaxies may be closely linked to that of elliptical galaxies, whereas fainter lenticulars might be more closely associated with ram-pressure stripped spiral galaxies. Finally, it is pointed out that fine details of the galaxy formation process might account for some of the differences between the classifications of the same galaxy by individual competent morphologists.« less

Laser damage metrology in biaxial nonlinear crystals using different test beams

NASA Astrophysics Data System (ADS)

Hildenbrand, Anne; Wagner, Frank R.; Akhouayri, Hassan; Natoli, Jean-Yves; Commandre, Mireille

2008-01-01

Laser damage measurements in nonlinear optical crystals, in particular in biaxial crystals, may be influenced by several effects proper to these materials or greatly enhanced in these materials. Before discussion of these effects, we address the topic of error bar determination for probability measurements. Error bars for the damage probabilities are important because nonlinear crystals are often small and expensive, thus only few sites are used for a single damage probability measurement. We present the mathematical basics and a flow diagram for the numerical calculation of error bars for probability measurements that correspond to a chosen confidence level. Effects that possibly modify the maximum intensity in a biaxial nonlinear crystal are: focusing aberration, walk-off and self-focusing. Depending on focusing conditions, propagation direction, polarization of the light and the position of the focus point in the crystal, strong aberrations may change the beam profile and drastically decrease the maximum intensity in the crystal. A correction factor for this effect is proposed, but quantitative corrections are not possible without taking into account the experimental beam profile after the focusing lens. The characteristics of walk-off and self-focusing have quickly been reviewed for the sake of completeness of this article. Finally, parasitic second harmonic generation may influence the laser damage behavior of crystals. The important point for laser damage measurements is that the amount of externally observed SHG after the crystal does not correspond to the maximum amount of second harmonic light inside the crystal.

RESONANT CLUMPING AND SUBSTRUCTURE IN GALACTIC DISKS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molloy, Matthew; Smith, Martin C.; Shen, Juntai

2015-05-10

We describe a method to extract resonant orbits from N-body simulations, exploiting the fact that they close in frames rotating with a constant pattern speed. Our method is applied to the N-body simulation of the Milky Way by Shen et al. This simulation hosts a massive bar, which drives strong resonances and persistent angular momentum exchange. Resonant orbits are found throughout the disk, both close to the bar and out to the very edges of the disk. Using Fourier spectrograms, we demonstrate that the bar is driving kinematic substructure even in the very outer parts of the disk. We identifymore » two major orbit families in the outskirts of the disk, one of which makes significant contributions to the kinematic landscape, namely, the m:l = 3:−2 family, resonating with the bar. A mechanism is described that produces bimodal distributions of Galactocentric radial velocities at selected azimuths in the outer disk. It occurs as a result of the temporal coherence of particles on the 3:−2 resonant orbits, which causes them to arrive simultaneously at pericenter or apocenter. This resonant clumping, due to the in-phase motion of the particles through their epicycle, leads to both inward and outward moving groups that belong to the same orbital family and consequently produce bimodal radial velocity distributions. This is a possible explanation of the bimodal velocity distributions observed toward the Galactic anticenter by Liu et al. Another consequence is that transient overdensities appear and dissipate (in a symmetric fashion), resulting in a periodic pulsing of the disk’s surface density.« less

Experimental effective intensity of steady and flashing light emitting diodes for aircraft anti-collision lighting.

DOT National Transportation Integrated Search

2013-08-01

Research was conducted to determine the effective intensity of flashing lights that incorporate light-emitting diodes (LEDs). LEDs require less power and have the ability to flash without the addition of moving parts. Compared with incandescent bulbs...

Space requirement of a prefabricated bar on two interforaminal implants: a prospective clinical study.

PubMed

Albrecht, Dominic; Ramierez, Ami; Kremer, Urs; Katsoulis, Joannis; Mericske-Stern, Regina; Enkling, Norbert

2015-02-01

This clinical study measured the dimensional changes of existing lower complete dentures due to the integration of a prefabricated implant bar. Additionally, the impact of this dimensional change on patient satisfaction and oral function was analyzed. Twenty edentulous patients (10 men/10 women; aged 65.9 ± 11.8 years) received two interforaminal implants. Subsequent to surgery, a chair side adapted, prefabricated bar (SFI Bar(®), C+M, Biel, Switzerland) was inserted, and the matrix was polymerized into the existing lower denture. The change of the denture's lingual dimension was recorded by means of a bicolored, silicone denture duplicate that was sectioned in the oro-vestibular direction in the regions of the symphysis (S) and the implants (I-left, I-right). On the sections, the dimensional increase was measured using a light microscope. Six months after bar insertion, patients answered a standardized questionnaire. All dentures exhibited increased lingual volume, more extensively at S than at I (P = 0.001). At S, the median diagonal size of the denture was doubled (+4.33 mm), and at I, the median increase was 50% (I-left/-right = +2.66/+2.62 mm). The original denture size influenced the volume increase (P = 0.024): smaller dentures led to a larger increase. The amount of denture increase did not have negative impact on either self-perceived oral function or patient satisfaction. Approximately, 95% of the patients were satisfied with the treatment results. The lingual size of a lower denture was enlarged by the integration of a prefabricated bar without any negative side effects. Thus, this attachment system is suitable to convert an existing full denture into an implant-supported overdenture. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Explanation of low efficiency droop in semipolar (202¯1¯) InGaN/GaN LEDs through evaluation of carrier recombination coefficients

NASA Astrophysics Data System (ADS)

Monavarian, Morteza; Rashidi, Arman; Aragon, Andrew; Oh, Sang H.; Nami, Mohsen; DenBaars, Steve P.; Feezell, Daniel

2017-08-01

We report the carrier dynamics and recombination coefficients in single-quantum-well semipolar $(20\\bar 2\\bar 1)$ InGaN/GaN light-emitting diodes emitting at 440 nm with 93% peak internal quantum efficiency. The differential carrier lifetime is analyzed for various injection current densities from 5 $A/cm^2$ to 10 $kA/cm^2$, and the corresponding carrier densities are obtained. The coupling of internal quantum efficiency and differential carrier lifetime vs injected carrier density ($n$) enables the separation of the radiative and nonradiative recombination lifetimes and the extraction of the Shockley-Read-Hall (SRH) nonradiative ($A$), radiative ($B$), and Auger ($C$) recombination coefficients and their $n$-dependency considering the saturation of the SRH recombination rate and phase-space filling. The results indicate a three to four-fold higher $A$ and a nearly two-fold higher $B_0$ for this semipolar orientation compared to that of $c$-plane reported using a similar approach [A. David and M. J. Grundmann, Appl. Phys. Lett. 96, 103504 (2010)]. In addition, the carrier density in semipolar $(20\\bar 2\\bar 1)$ is found to be lower than the carrier density in $c$-plane for a given current density, which is important for suppressing efficiency droop. The semipolar LED also shows a two-fold lower $C_0$ compared to $c$-plane, which is consistent with the lower relative efficiency droop for the semipolar LED (57% vs. 69%). The lower carrier density, higher $B_0$ coefficient, and lower $C_0$ (Auger) coefficient are directly responsible for the high efficiency and low efficiency droop reported in semipolar $(20\\bar 2\\bar 1)$ LEDs.

Direct manipulation of tool-like masters for controlling a master-slave surgical robotic system.

PubMed

Zhang, Linan; Zhou, Ningxin; Wang, Shuxin

2014-12-01

Robotic-assisted minimally invasive surgery (MIS) can benefit both patients and surgeons. However, the learning curve for robotically assisted procedures can be long and the total system costs are high. Therefore, there is considerable interest in new methods and lower cost controllers for a surgical robotic system. In this study, a knife-master and a forceps-master, shaped similarly to a surgical knife and forceps, were developed as input devices for control of a master-slave surgical robotic system. In addition, a safety strategy was developed to eliminate the master-slave orientation difference and stabilize the surgical system. Master-slave tracking experiments and a ring-and-bar experiment showed that the safety tracking strategy could ensure that the robot system moved stably without any tremor in the tracking motion. Subjects could manipulate the surgical tool to achieve the master-slave operation with less training compared to a mechanical master. Direct manipulation of the small, light and low-cost surgical tools to control a robotic system is a possible operating mode. Surgeons can operate the robotic system in their own familiar way, without long training. The main potential safety issues can be solved by the proposed safety control strategy. Copyright © 2013 John Wiley & Sons, Ltd.

Influence of survey strategy and interpolation model on DEM quality

NASA Astrophysics Data System (ADS)

Heritage, George L.; Milan, David J.; Large, Andrew R. G.; Fuller, Ian C.

2009-11-01

Accurate characterisation of morphology is critical to many studies in the field of geomorphology, particularly those dealing with changes over time. Digital elevation models (DEMs) are commonly used to represent morphology in three dimensions. The quality of the DEM is largely a function of the accuracy of individual survey points, field survey strategy, and the method of interpolation. Recommendations concerning field survey strategy and appropriate methods of interpolation are currently lacking. Furthermore, the majority of studies to date consider error to be uniform across a surface. This study quantifies survey strategy and interpolation error for a gravel bar on the River Nent, Blagill, Cumbria, UK. Five sampling strategies were compared: (i) cross section; (ii) bar outline only; (iii) bar and chute outline; (iv) bar and chute outline with spot heights; and (v) aerial LiDAR equivalent, derived from degraded terrestrial laser scan (TLS) data. Digital Elevation Models were then produced using five different common interpolation algorithms. Each resultant DEM was differentiated from a terrestrial laser scan of the gravel bar surface in order to define the spatial distribution of vertical and volumetric error. Overall triangulation with linear interpolation (TIN) or point kriging appeared to provide the best interpolators for the bar surface. Lowest error on average was found for the simulated aerial LiDAR survey strategy, regardless of interpolation technique. However, comparably low errors were also found for the bar-chute-spot sampling strategy when TINs or point kriging was used as the interpolator. The magnitude of the errors between survey strategy exceeded those found between interpolation technique for a specific survey strategy. Strong relationships between local surface topographic variation (as defined by the standard deviation of vertical elevations in a 0.2-m diameter moving window), and DEM errors were also found, with much greater errors found at slope breaks such as bank edges. A series of curves are presented that demonstrate these relationships for each interpolation and survey strategy. The simulated aerial LiDAR data set displayed the lowest errors across the flatter surfaces; however, sharp slope breaks are better modelled by the morphologically based survey strategy. The curves presented have general application to spatially distributed data of river beds and may be applied to standard deviation grids to predict spatial error within a surface, depending upon sampling strategy and interpolation algorithm.

Scavenging of ammonia by raindrops in Saturn's great storm clouds

NASA Astrophysics Data System (ADS)

Delitsky, M. L.; Baines, Kevin

2016-10-01

Observations of the great Saturn storms of 2010-2011 by Cassini instruments showed a very large depletion in atmospheric ammonia. While dynamics will play a role, the very high solubility of ammonia in water may be another important contributor to ammonia depletion in storms. Ammonia exists in Earth's atmosphere and rainstorms dissolve ammonia to a great degree, leaving almost no NH3 in the atmosphere. Studies by Elperin et al (2011, 2013) show that scavenging of ammonia is greatest as a rainstorm starts and lessens as raindrops fall, tapering off to almost zero by the time the rain reaches the ground (Elperin et al 2009). Ammonia is reaching saturation as it dissolves in the aqueous solution. As concentration increases, NH3 is then converted to aqueous species (NH3)x.(H2O)y (Max and Chapados 2013).Ammonia has the highest solubility in water compared to all other gases in the Saturn atmosphere. The Henry's Law constant for NH3 in water is 60 M/atm at 25 C. For H2S, it is 0.001 M/atm. In Saturn storms, it is "raining UP": As water-laden storm clouds convectively rise, ammonia gas will be scavenged and go into solution to a great degree, whilst all the other gases remain mostly in the gas phase. Aqueous ammonia acts as an antifreeze: if ammonia is dissolved in water cloud droplets to the limit of its solubility, as water droplets rise, they can stay liquid (and continue to scavenge NH3) to well below their normal freezing point of 0 Celsius (273 K). The freezing point for a 30 wt % water-ammonia solution is ~189 K. The pressure level where T = 189 K is at 2.8 bars. The normal freezing point of water occurs at the 9 bar pressure level in Saturn's atmosphere. 2.8 bars occurs at the -51 km altitude (below the 1 bar level). 9 bars is at the -130 km level: a difference of 79 km. A water droplet containing 30 wt% NH3 can move upwards from 9 bars to 2.8 bars (79 km) and still remain liquid, only freezing above that altitude. Calculations by the E-AIM model show that ammonia becomes the dominant species as the water droplets rise and cool. Ammonia will be effectively depleted as it is scavenged into water droplets in Saturn's storms.

Stimulation of hair cells with ultraviolet light

NASA Astrophysics Data System (ADS)

Azimzadeh, Julien B.; Fabella, Brian A.; Hudspeth, A. J.

2018-05-01

Hair bundles are specialized organelles that transduce mechanical inputs into electrical outputs. To activate hair cells, physiologists have resorted to mechanical methods of hair-bundle stimulation. Here we describe a new method of hair-bundle stimulation, irradiation with ultraviolet light. A hair bundle illuminated by ultraviolet light rapidly moves towards its tall edge, a motion typically associated with excitatory stimulation. The motion disappears upon tip-link rupture and is associated with the opening of mechanotransduction channels. Hair bundles can be induced to move sinusoidally with oscillatory modulation of the stimulation power. We discuss the implications of ultraviolet stimulation as a novel hair-bundle stimulus.

Amazon river flow regime and flood recessional agriculture: Flood stage reversals and risk of annual crop loss

NASA Astrophysics Data System (ADS)

Coomes, Oliver T.; Lapointe, Michel; Templeton, Michael; List, Geneva

2016-08-01

The annual flood cycle is an important driver of ecosystem structure and function in large tropical rivers such as the Amazon. Riparian peasant communities rely on river fishing and annual floodplain agriculture, closely adapted to the recession phase of the flood pulse. This article reports on a poorly documented but important challenge facing farmers practicing flood recessional agriculture along the Amazon river: frequent, unpredictable stage reversals (repiquetes) which threaten to ruin crops growing on channel bars. We assess the severity of stage reversals for rice production on exposed river mud bars (barreales) near Iquitos, Peru. Crop loss risk is estimated based on a quantitative analysis of 45 years of daily Amazon stage data and field data from floodplain communities nearby in the Muyuy archipelago, upstream of Iquitos. Rice varieties selected, elevations of silt rich bars where rice is sown, as well as planting and harvest dates are analyzed in the light of the timing, frequencies and amplitudes of observed stage reversals that have the potential to destroy growing rice. We find that unpredictable stage reversals can produce substantial crop losses and shorten significantly the length of average growing seasons on lower elevation river bars. The data reveal that local famers extend planting down to lower bar elevations where the mean probabilities of re-submergence before rice maturity (due to reversals) approach 50%, below which they implicitly consider that the risk of crop loss outweighs the potential reward of planting.

Constraints on light mediators: Confronting dark matter searches with B physics

NASA Astrophysics Data System (ADS)

Schmidt-Hoberg, Kai; Staub, Florian; Winkler, Martin Wolfgang

2013-12-01

Light scalars appear in many well-motivated extensions of the Standard Model including supersymmetric models with additional gauge singlets. Such scalars could mediate the interactions between dark matter and nuclei, giving rise to the tentative signals observed by several dark matter direct detection experiments including CDMS-Si. In this Letter, we derive strong new limits on light scalar mediators by using the LHCb, Belle and BaBar searches for rare ϒ and B decays. These limits rule out significant parts of the parameter space favored by CDMS-Si. Nevertheless, as current searches are not optimized for investigating weakly coupled light scalars, a further increase in experimental sensitivity could be achieved by relaxing requirements in the event selection.

Creating stimuli for the study of biological-motion perception.

PubMed

Dekeyser, Mathias; Verfaillie, Karl; Vanrie, Jan

2002-08-01

In the perception of biological motion, the stimulus information is confined to a small number of lights attached to the major joints of a moving person. Despite this drastic degradation of the stimulus information, the human visual apparatus organizes the swarm of moving dots into a vivid percept of a moving biological creature. Several techniques have been proposed to create point-light stimuli: placing dots at strategic locations on photographs or films, video recording a person with markers attached to the body, computer animation based on artificial synthesis, and computer animation based on motion-capture data. A description is given of the technique we are currently using in our laboratory to produce animated point-light figures. The technique is based on a combination of motion capture and three-dimensional animation software (Character Studio, Autodesk, Inc., 1998). Some of the advantages of our approach are that the same actions can be shown from any viewpoint, that point-light versions, as well as versions with a full-fleshed character, can be created of the same actions, and that point lights can indicate the center of a joint (thereby eliminating several disadvantages associated with other techniques).

Three-Dimensional Analysis of Voids in AM60B Magnesium Tensile Bars Using Computed Tomography Imagery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waters, A M

2001-05-01

In an effort to increase automobile fuel efficiency as well as decrease the output of harmful greenhouse gases, the automotive industry has recently shown increased interest in cast light metals such as magnesium alloys in an effort to increase weight savings. Currently several magnesium alloys such as AZ91 and AM60B are being used in structural applications for automobiles. However, these magnesium alloys are not as well characterized as other commonly used structural metals such as aluminum. This dissertation presents a methodology to nondestructively quantify damage accumulation due to void behavior in three dimensions in die-cast magnesium AM60B tensile bars asmore » a function of mechanical load. Computed tomography data was acquired after tensile bars were loaded up to and including failure, and analyzed to characterize void behavior as it relates to damage accumulation. Signal and image processing techniques were used along with a cluster labeling routine to nondestructively quantify damage parameters in three dimensions. Void analyses were performed including void volume distribution characterization, nearest neighbor distance calculations, shape parameters, and volumetric renderings of voids in the alloy. The processed CT data was used to generate input files for use in finite element simulations, both two- and three-dimensional. The void analyses revealed that the overwhelming source of failure in each tensile bar was a ring of porosity within each bar, possibly due to a solidification front inherent to the casting process. The measured damage parameters related to void nucleation, growth, and coalescence were shown to contribute significantly to total damage accumulation. Void volume distributions were characterized using a Weibull function, and the spatial distributions of voids were shown to be clustered. Two-dimensional finite element analyses of the tensile bars were used to fine-tune material damage models and a three-dimensional mesh of an extracted portion of one tensile bar including voids was generated from CT data and used as input to a finite element analysis.« less

GETTING TO THE HEART OF A GALAXY

NASA Technical Reports Server (NTRS)

2002-01-01

This collage of images in visible and infrared light reveals how the barred spiral galaxy NGC 1365 is feeding material into its central region, igniting massive star birth and probably causing its bulge of stars to grow. The material also is fueling a black hole in the galaxy's core. A galaxy's bulge is a central, football-shaped structure composed of stars, gas, and dust. The black-and-white image in the center, taken by a ground-based telescope, displays the entire galaxy. But the telescope's resolution is not powerful enough to reveal the flurry of activity in the galaxy's hub. The blue box in the galaxy's central region outlines the area observed by the NASA Hubble Space Telescope's visible-light camera, the Wide Field and Planetary Camera 2 (WFPC2). The red box pinpoints a narrower view taken by the Hubble telescope's infrared camera, the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). A barred spiral is characterized by a lane of stars, gas, and dust slashing across a galaxy's central region. It has a small bulge that is dominated by a disk of material. The spiral arms begin at both ends of the bar. The bar is funneling material into the hub, which triggers star formation and feeds the bulge. The visible-light picture at upper left is a close-up view of the galaxy's hub. The bright yellow orb is the nucleus. The dark material surrounding the orb is gas and dust that is being funneled into the central region by the bar. The blue regions pinpoint young star clusters. In the infrared image at lower right, the Hubble telescope penetrates the dust seen in the WFPC2 picture to reveal more clusters of young stars. The bright blue dots represent young star clusters; the brightest of the red dots are young star clusters enshrouded in dust and visible only in the infrared image. The fainter red dots are older star clusters. The WFPC2 image is a composite of three filters: near-ultraviolet (3327 Angstroms), visible (5552 Angstroms), and near-infrared (8269 Angstroms). The NICMOS image, taken at a wavelength of 16,000 Angstroms, was combined with the visible and near-infrared wavelengths taken by WFPC2. The WFPC2 image was taken in January 1996; the NICMOS data were taken in April 1998. Credits for the ground-based image: Allan Sandage (The Observatories of the Carnegie Institution of Washington) and John Bedke (Computer Sciences Corporation and the Space Telescope Science Institute) Credits for the WFPC2 image: NASA and John Trauger (Jet Propulsion Laboratory) Credits for the NICMOS image: NASA, ESA, and C. Marcella Carollo (Columbia University)

Position indicator

DOEpatents

Tanner, David E.

1981-01-01

A nuclear reactor system is described in which a position indicator is provided for detecting and indicating the position of a movable element inside a pressure vessel. The movable element may be a valve element or similar device which moves about an axis. Light from a light source is transmitted from a source outside the pressure vessel to a first region inside the pressure vessel in alignment with the axis of the movable element. The light is redirected by a reflector prism to a second region displaced radially from the first region. The reflector prism moves in response to movement of the movable element about its axis such that the second region moves arcuately with respect to the first region. Sensors are arrayed in an arc corresponding to the arc of movement of the second region and signals are transmitted from the sensors to the exterior of the reactor vessel to provide indication of the position of the movable element.

Optic probe for multiple angle image capture and optional stereo imaging

DOEpatents

Malone, Robert M.; Kaufman, Morris I.

2016-11-29

A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

Photonic Doppler velocimetry lens array probe incorporating stereo imaging

DOEpatents

Malone, Robert M.; Kaufman, Morris I.

2015-09-01

A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

Novel packaging for CW and QCW diode laser modules for operation with high power and duty cycles

NASA Astrophysics Data System (ADS)

Fassbender, Wilhelm; Lotz, Jens; Kissel, Heiko; Biesenbach, Jens

2018-02-01

Continuous wave (CW) and quasi-continuous wave (QCW) operated diode laser bars and arrays have found a wide range of industrial, medical, scientific, military and space applications with a broad variety in wavelength, pulse energy, pulse duration and beam quality. Recent applications require even higher power, duty cycles and power density. The heat loss will be dissipated by conductive cooling or liquid cooling close to the bars. We present the latest performance and reliability data of two novel high-brightness CW and QCW arrays of customized and mass-production modules, in compact and robust industry design for operation with high power and high duty cycles. All designs are based on single diode packages consisting of 10mm laser bars, soft or hard soldered between expansion matched submounts. The modular components cover a wide span of designs which differ basically in water/conduction (active/passive) cooled, single, linear (horizontal and vertical) arranged designs, as well as housed and unhoused modules. The different assembling technologies of active and passive cooled base plates affect the heat dissipation and therefore the reachable power at different QCW operating conditions, as well as the lifetime. As an example, a package consisting of 8 laser diodes, connected to a 28.8*13.5*7.0mm3 DCB (direct copper bonded) submount, passively or actively cooled is considered. This design is of particular interest for mobile applications seamless module to module building system, with an infinite number of laser bars at 1.7mm pitch. Using 940nm bars we can reach an optical output power per bar of 450W at 25°C base plate temperature with 10Hz, 1.2% duty cycle and 1.2ms pulse duration. As an additional example, micro channel coolers can be vertically stacked up to 50 diodes with a 1,15mm pitch. This design is suitable for all applications, demanding also compactness and light weight and high power density. Using near infrared bars and others, we can reach an optical output power of 250W per bar at 25°C coolant temperature at CW operation.

THE HST/ACS COMA CLUSTER SURVEY. VIII. BARRED DISK GALAXIES IN THE CORE OF THE COMA CLUSTER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marinova, Irina; Jogee, Shardha; Weinzirl, Tim

2012-02-20

We use high-resolution ({approx}0.''1) F814W Advanced Camera for Surveys (ACS) images from the Hubble Space Telescope ACS Treasury survey of the Coma cluster at z {approx} 0.02 to study bars in massive disk galaxies (S0s), as well as low-mass dwarf galaxies in the core of the Coma cluster, the densest environment in the nearby universe. Our study helps to constrain the evolution of bars and disks in dense environments and provides a comparison point for studies in lower density environments and at higher redshifts. Our results are: (1) we characterize the fraction and properties of bars in a sample ofmore » 32 bright (M{sub V} {approx}< -18, M{sub *} > 10{sup 9.5} M{sub Sun }) S0 galaxies, which dominate the population of massive disk galaxies in the Coma core. We find that the measurement of a bar fraction among S0 galaxies must be handled with special care due to the difficulty in separating unbarred S0s from ellipticals, and the potential dilution of the bar signature by light from a relatively large, bright bulge. The results depend sensitively on the method used: the bar fraction for bright S0s in the Coma core is 50% {+-} 11%, 65% {+-} 11%, and 60% {+-} 11% based on three methods of bar detection, namely, strict ellipse fit criteria, relaxed ellipse fit criteria, and visual classification. (2) We compare the S0 bar fraction across different environments (the Coma core, A901/902, and Virgo) adopting the critical step of using matched samples and matched methods in order to ensure robust comparisons. We find that the bar fraction among bright S0 galaxies does not show a statistically significant variation (within the error bars of {+-}11%) across environments which span two orders of magnitude in galaxy number density (n {approx} 300-10,000 galaxies Mpc{sup -3}) and include rich and poor clusters, such as the core of Coma, the A901/902 cluster, and Virgo. We speculate that the bar fraction among S0s is not significantly enhanced in rich clusters compared to low-density environments for two reasons. First, S0s in rich clusters are less prone to bar instabilities as they are dynamically heated by harassment and are gas poor as a result of ram pressure stripping and accelerated star formation. Second, high-speed encounters in rich clusters may be less effective than slow, strong encounters in inducing bars. (3) We also take advantage of the high resolution of the ACS ({approx}50 pc) to analyze a sample of 333 faint (M{sub V} > -18) dwarf galaxies in the Coma core. Using visual inspection of unsharp-masked images, we find only 13 galaxies with bar and/or spiral structure. An additional eight galaxies show evidence for an inclined disk. The paucity of disk structures in Coma dwarfs suggests that either disks are not common in these galaxies or that any disks present are too hot to develop instabilities.« less

Study on the near-field non-linearity (SMILE) of high power diode laser arrays

NASA Astrophysics Data System (ADS)

Zhang, Hongyou; Jia, Yangtao; Li, Changxuan; Zah, Chung-en; Liu, Xingsheng

2018-02-01

High power laser diodes have been found a wide range of industrial, space, medical applications, characterized by high conversion efficiency, small size, light weight and a long lifetime. However, due to thermal induced stress, each emitter in a semiconductor laser bar or array is displaced along p-n junction, resulting of each emitter is not in a line, called Near-field Non-linearity. Near-field Non-linearity along laser bar (also known as "SMILE") determines the outcome of optical coupling and beam shaping [1]. The SMILE of a laser array is the main obstacle to obtain good optical coupling efficiency and beam shaping from a laser array. Larger SMILE value causes a larger divergence angle and a wider line after collimation and focusing, respectively. In this letter, we simulate two different package structures based on MCC (Micro Channel Cooler) with Indium and AuSn solders, including the distribution of normal stress and the SMILE value. According to the theoretical results, we found the distribution of normal stress on laser bar shows the largest in the middle and drops rapidly near both ends. At last, we did another experiment to prove that the SMILE value of a laser bar was mainly affected by the die bonding process, rather than the operating condition.

Search for a light charged Higgs boson decaying to $$ \\mathrm{ c \\bar{s} } $$ in pp collisions at $$ \\sqrt{s} =$$ 8 TeV

DOE PAGES

Khachatryan, Vardan

2015-12-29

Our search for a light charged Higgs boson, originating from the decay of a top quark and subsequently decaying into a charm quark and a strange antiquark, is presented. The data used in the analysis correspond to an integrated luminosity of 19.7 fb -1 recorded in proton-proton collisions at √s = 8 TeV by the CMS experiment at the LHC. The search is performed in the process tt - W ±bH ∓b -, where the W boson decays to a lepton (electron or muon) and a neutrino. Furthermore, the decays lead to a final state comprising an isolated lepton, atmore » least four jets and large missing transverse energy. No significant deviation is observed in the data with respect to the standard model predictions, and model-independent upper limits are set on the branching fraction B(t→ H +b), ranging from 1.2 to 6.5% for a charged Higgs boson with mass between 90 and 160 GeV, under the assumption that B(H + →cs -) = 100%.« less

Hybrid tunnel junction contacts to III-nitride light-emitting diodes

NASA Astrophysics Data System (ADS)

Young, Erin C.; Yonkee, Benjamin P.; Wu, Feng; Oh, Sang Ho; DenBaars, Steven P.; Nakamura, Shuji; Speck, James S.

2016-02-01

In this work, we demonstrate highly doped GaN p-n tunnel junction (TJ) contacts on III-nitride heterostructures where the active region of the device and the top p-GaN layers were grown by metal organic chemical vapor deposition and highly doped n-GaN was grown by NH3 molecular beam epitaxy to form the TJ. The regrowth interface in these hybrid devices was found to have a high concentration of oxygen, which likely enhanced tunneling through the diode. For optimized regrowth, the best tunnel junction device had a total differential resistivity of 1.5 × 10-4 Ω cm2, including contact resistance. As a demonstration, a blue-light-emitting diode on a (20\\bar{2}\\bar{1}) GaN substrate with a hybrid tunnel junction and an n-GaN current spreading layer was fabricated and compared with a reference sample with a transparent conducting oxide (TCO) layer. The tunnel junction LED showed a lower forward operating voltage and a higher efficiency at a low current density than the TCO LED.

Seeing the Light

ERIC Educational Resources Information Center

Sportel, Samuel; Bruxvoort, Crystal; Jadrich, James

2009-01-01

Conceptually, students are typically introduced to light as a type of wave. However, children struggle to understand this model because it is highly abstract. Light can be represented more concretely using the photon model. According to this scientific model, light emanates from sources as tiny "packets" of energy (called "photons") that move in…

The integration of habits maintained by food and water reinforcement through stimulus compounding.

PubMed Central

Weiss, S J; Schindler, C W; Eason, R

1988-01-01

In Experiment 1, a light and a tone were correlated independently with water reinforcement of bar pressing by rats. With different naive subjects in Experiment 2, one of these stimuli was correlated with food and the other with water reinforcement (counterbalanced). In both experiments the absence of tone and light signaled extinction. Tests of stimulus-reinforcer independence in Experiment 2 indicated that tone and light controlled behavior whose rate was specifically affected by deprivation state. In the stimulus-compounding tests of both experiments, response rates were higher to tone-plus-light than to tone or light presented alone (additive summation). This is the first report of additive summation produced through compounding stimuli paired with different reinforcers. The results are discussed in the context of the effects of incentive motivation on operant performance. PMID:3193056

Projection of controlled repeatable real-time moving targets to test and evaluate motion imagery quality

NASA Astrophysics Data System (ADS)

Scopatz, Stephen D.; Mendez, Michael; Trent, Randall

2015-05-01

The projection of controlled moving targets is key to the quantitative testing of video capture and post processing for Motion Imagery. This presentation will discuss several implementations of target projectors with moving targets or apparent moving targets creating motion to be captured by the camera under test. The targets presented are broadband (UV-VIS-IR) and move in a predictable, repeatable and programmable way; several short videos will be included in the presentation. Among the technical approaches will be targets that move independently in the camera's field of view, as well targets that change size and shape. The development of a rotating IR and VIS 4 bar target projector with programmable rotational velocity and acceleration control for testing hyperspectral cameras is discussed. A related issue for motion imagery is evaluated by simulating a blinding flash which is an impulse of broadband photons in fewer than 2 milliseconds to assess the camera's reaction to a large, fast change in signal. A traditional approach of gimbal mounting the camera in combination with the moving target projector is discussed as an alternative to high priced flight simulators. Based on the use of the moving target projector several standard tests are proposed to provide a corresponding test to MTF (resolution), SNR and minimum detectable signal at velocity. Several unique metrics are suggested for Motion Imagery including Maximum Velocity Resolved (the measure of the greatest velocity that is accurately tracked by the camera system) and Missing Object Tolerance (measurement of tracking ability when target is obscured in the images). These metrics are applicable to UV-VIS-IR wavelengths and can be used to assist in camera and algorithm development as well as comparing various systems by presenting the exact scenes to the cameras in a repeatable way.

A novel single-ended readout depth-of-interaction PET detector fabricated using sub-surface laser engraving.

PubMed

Uchida, H; Sakai, T; Yamauchi, H; Hakamata, K; Shimizu, K; Yamashita, T

2016-09-21

We propose a novel scintillation detector design for positron emission tomography (PET), which has depth of interaction (DOI) capability and uses a single-ended readout scheme. The DOI detector contains a pair of crystal bars segmented using sub-surface laser engraving (SSLE). The two crystal bars are optically coupled to each other at their top segments and are coupled to two photo-sensors at their bottom segments. Initially, we evaluated the performance of different designs of single crystal bars coupled to photomultiplier tubes at both ends. We found that segmentation by SSLE results in superior performance compared to the conventional method. As the next step, we constructed a crystal unit composed of a 3  ×  3  ×  20 mm 3 crystal bar pair, with each bar containing four layers segmented using the SSLE. We measured the DOI performance by changing the optical conditions for the crystal unit. Based on the experimental results, we then assessed the detector performance in terms of the DOI capability by evaluating the position error, energy resolution, and light collection efficiency for various crystal unit designs with different bar sizes and a different number of layers (four to seven layers). DOI encoding with small position error was achieved for crystal units composed of a 3  ×  3  ×  20 mm 3 LYSO bar pair having up to seven layers, and with those composed of a 2  ×  2  ×  20 mm 3 LYSO bar pair having up to six layers. The energy resolution of the segment in the seven-layer 3  ×  3  ×  20 mm 3 crystal bar pair was 9.3%-15.5% for 662 keV gamma-rays, where the segments closer to the photo-sensors provided better energy resolution. SSLE provides high geometrical accuracy at low production cost due to the simplicity of the crystal assembly. Therefore, the proposed DOI detector is expected to be an attractive choice for practical small-bore PET systems dedicated to imaging of the brain, breast, and small animals.

Face pumping of thin, solid-state slab lasers with laser diodes.

PubMed

Faulstich, A; Baker, H J; Hall, D R

1996-04-15

A new technique for face pumping of slab lasers uses transfer of light from 10 quasi-cw laser diode bars through a slotted mirror into a rectangular, highly ref lective pump chamber, giving efficient multipass pumping of a thin Nd:glass slab laser. A slope efficiency of 28% and a maximum pulse energy of 65 mJ have been obtained, and gain and loss measurements with thickness t = 0.45-1.04 mm have confirmed the 1/t scaling of gain in thin slabs and the high efficiency of pump light transfer.

Hubble Sees Elegant Spiral Hiding a Hungry Monster

NASA Image and Video Library

2017-12-08

NGC 4639 is a beautiful example of a type of galaxy known as a barred spiral. It lies over 70 million light-years away in the constellation of Virgo and is one of about 1,500 galaxies that make up the Virgo Cluster. In this image, taken by the NASA/ESA Hubble Space Telescope, one can clearly see the bar running through the bright, round core of the galaxy. Bars are found in around two-thirds of spiral galaxies, and are thought to be a natural phase in their evolution. The galaxy’s spiral arms are sprinkled with bright regions of active star formation. Each of these tiny jewels is actually several hundred light-years across and contains hundreds or thousands of newly formed stars. But NGC 4639 also conceals a dark secret in its core — a massive black hole that is consuming the surrounding gas. This is known as an active galactic nucleus (AGN), and is revealed by characteristic features in the spectrum of light from the galaxy and by X-rays produced close to the black hole as the hot gas plunges towards it. Most galaxies are thought to contain a black hole at the center. NGC 4639 is in fact a very weak example of an AGN, demonstrating that AGNs exist over a large range of activity, from galaxies like NGC 4639 to distant quasars, where the parent galaxy is almost completely dominated by the emissions from the AGN. Image credit: ESA/Hubble & NASA NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Our Chaotic Neighbor

NASA Image and Video Library

2006-09-01

This vibrant image from NASA's Spitzer Space Telescope shows the Large Magellanic Cloud, a satellite galaxy to our own Milky Way galaxy. The infrared image, a mosaic of more than 100,000 individual tiles, offers astronomers a unique chance to study the lifecycle of stars and dust in a single galaxy. Nearly one million objects are revealed for the first time in this Spitzer view, which represents about a 1,000-fold improvement in sensitivity over previous space-based missions. Most of the new objects are dusty stars of various ages populating the Large Magellanic Cloud; the rest are thought to be background galaxies. The blue color in the picture, seen most prominently in the central bar, represents starlight from older stars. The chaotic, bright regions outside this bar are filled with hot, massive stars buried in thick blankets of dust. The red clouds contain cooler interstellar gas and molecular-sized dust grains illuminated by ambient starlight. The Large Magellanic Cloud, located 160,000 light-years from Earth, is one of a handful of dwarf galaxies that orbit our own Milky Way. It is approximately one-third as wide as the Milky Way, and, if it could be seen in its entirety, would cover the same amount of sky as a grid of about 480 full moons. About one-third of the whole galaxy can be seen in the Spitzer image. This picture is a composite of infrared light captured by Spitzer's infrared array camera. Light with wavelengths of 8 and 5.8 microns is red and orange: 4.5-micron light is green; and 3.6-micron light is blue. http://photojournal.jpl.nasa.gov/catalog/PIA07136

The SAMI Galaxy Survey: gas streaming and dynamical M/L in rotationally supported systems

NASA Astrophysics Data System (ADS)

Cecil, G.; Fogarty, L. M. R.; Richards, S.; Bland-Hawthorn, J.; Lange, R.; Moffett, A.; Catinella, B.; Cortese, L.; Ho, I.-T.; Taylor, E. N.; Bryant, J. J.; Allen, J. T.; Sweet, S. M.; Croom, S. M.; Driver, S. P.; Goodwin, M.; Kelvin, L.; Green, A. W.; Konstantopoulos, I. S.; Owers, M. S.; Lawrence, J. S.; Lorente, N. P. F.

2016-02-01

Line-of-sight velocities of gas and stars can constrain dark matter (DM) within rotationally supported galaxies if they trace circular orbits extensively. Photometric asymmetries may signify non-circular motions, requiring spectra with dense spatial coverage. Our integral-field spectroscopy of 178 galaxies spanned the mass range of the Sydney-AAO Multi-object integral field spectrograph (SAMI) Galaxy Survey. We derived circular speed curves (CSCs) of gas and stars from non-parametric fits out to r ˜ 2re. For 12/14 with measured H I profiles, ionized gas and H I maximum velocities agreed. We fitted mass-follows-light models to 163 galaxies by approximating the radial light profile as nested, very flattened mass homeoids viewed as a Sérsic form. Fitting broad-band spectral energy distributions to Sloan Digital Sky Survey images gave median stellar mass/light 1.7 assuming a Kroupa initial mass function (IMF) versus 2.6 dynamically. Two-thirds of the dynamical mass/light measures were consistent with star+remnant IMFs. One-fifth required upscaled starlight to fit, hence comparable mass of unobserved baryons and/or DM distributed like starlight across the SAMI aperture that came to dominate motions as the starlight CSCs declined rapidly. The rest had mass distributed differently from light. Subtracting fits of Sérsic radial profiles to 13 VIKING Z-band images revealed residual weak bars. Near the bar major axis, we assessed m = 2 streaming velocities, and found deviations usually <30 km s-1 from the CSC; three showed no deviation. Thus, asymmetries rarely influenced the CSC despite colocated shock-indicating, emission-line flux ratios in more than 2/3 of our sample.

Light and heavy touch reduces postural sway and modifies axial tone in Parkinson’s disease

PubMed Central

Franzén, Erika; Paquette, Caroline; Gurfinkel, Victor; Horak, Fay

2014-01-01

Background Light touch with a stable object reduces postural sway by increasing axial postural tone in healthy subjects. However, it is unknown whether subjects with Parkinson’s disease (PD), who have more postural sway and higher axial postural tone than healthy subjects, can benefit from haptic touch. Objective To investigate the effect of light and heavy touch on postural stability and hip tone in subjects with PD. Methods Fourteen subjects with mid-stage PD, and 14 healthy control subjects were evaluated during quiet standing with eyes closed with their arms: 1) crossed, 2) lightly touching a fixed rigid bar in front of them and 3) firmly gripping the bar. Postural sway was measured with a forceplate and axial hip tone was quantified using a unique device that measures the resistance of the hips to yaw rotation while maintaining active stance. Results Subjects with PD significantly decreased their postural sway with light or heavy touch (p<0.001 vs. arms crossed), similarly as control subjects. Without touch, hip tone was larger in PD subjects. With touch, however, tone values were similar in both groups. This change in hip tone with touch was highly correlated with the initial amount of tone (PD: r=− 0.72 to −0.95 and controls: r=−0.74 to−0.85). Conclusions We showed, for the first time, that subjects with PD benefit from touch similarly to control subjects and that despite higher axial postural tone, PD subjects are able to modulate their tone with touch. Future studies should investigate the complex relationship between touch and postural tone. PMID:22415944

The role of the faceguard in the production of flexion injuries to the cervical spine in football.

PubMed

Melvin, W J; Dunlop, H W; Hetherington, R F; Kerr, J W

1965-11-20

The precise role of the single-bar face mask in producing major flexion violence to the cervical spine has been studied by review of game movies, analysis of the radiographs and detailed interviews with two players who sustained fractures of cervical spine. The single-bar face mask can become fixed in the ground, thereby forcing a runner's head down onto his chest as the trunk moves forward. Preventive measures embodying modifications in the face mask, strict coaching in football techniques and the institution of safety factors in the playing rules are proposed. Appreciation of the mechanism of injury is urged in order to encourage careful inspection of protective head gear as well as to direct the attention of team physicians to the possibility of serious flexion injury to the cervical spine occurring without dramatic evidence. This report is not a plea for abandonment of the face mask but rather a suggestion for careful selection of a safe and efficient mask.

STS-56 Earth observation of a sun-glinted ocean along the coast of Somalia

NASA Technical Reports Server (NTRS)

1993-01-01

STS-56 Earth observation taken aboard Discovery, Orbiter Vehicle (OV) 103, is of a sun-glinted ocean along the northeastern coast of Somalia. The small island of Xaafuun is connected to the mainland by a well-developed double tombolo-two sand bars. Between the two toombolos a lagoon is formed which gradually fills with sediment and becomes a flat sand bar. Better known double tombolos include those of Gibraltar, the now-partially submerged giant tombolos forming Adam's Bridge (Palk Strait) connecting Sri Lanka to India, Monte Argentario in Italy, and Long Island, New York. Such tombolos usually indicate a constant sediment source and a strong unidirectional or bi-directional (monsoonal) long shore current. In this case, sediment is provided by the plumes of the major African rivers debauching into the Mozambique Channel. The sediment is carried predominately to the northeast along the coast by the swiftly moving monsoonal Agulhas Current. Visible in this scene are internal waves, shear

The Sidebar Computer Program, a seismic-shaking intensity meter: users' manual and software description

USGS Publications Warehouse

Evans, John R.

2003-01-01

The SideBar computer program provides a visual display of seismic shaking intensity as recorded at one specific seismograph. This software allows a user to tap into the seismic data recorded on that specific seismograph and to display the overall level of shaking at the single location where that seismograph resides (usually the same place the user is). From this shaking level, SideBar also estimates the potential for damage nearby. SideBar cannot tell you the “Richter magnitude” of the earthquake (see box), only how hard the ground shook locally and this estimate of how much damage is likely in the neighborhood. This combination of local effects is called the “seismic intensity”. SideBar runs on a standard desktop or laptop PC, and is intended for the media, schools, emergency responders, and any other group hosting a seismograph and who want to know immediately after an earthquake the levels of shaking measured by that instrument. These local values can be used to inform the public and help initiate appropriate local emergency response activities in the minutes between the earthquake and availability of the broader coverage provided by the USGS over the Web, notably by ShakeMap. For example, for instruments installed in schools, the level of shaking and likely damage at the school could immediately be Web broadcast and parents could quickly determine the likely safety of their children—their biggest postearthquake concern. Also, in the event of a Web outage, SideBar may be a continuing primary source of local emergency response information for some additional minutes. Specifically, SideBar interprets the peak level of acceleration (that is, the force of shaking, as a percentage of the force of gravity) as well as the peak velocity, or highest speed, at which the ground moves. Using these two basic measurements, SideBar computes what is called Instrumental Intensity—a close approximation of the Modified Mercalli Intensity scale, or “MMI” (using the Wald et al., 1999a, relationships between acceleration, velocity, and shaking intensity). Intensity is a measure of local shaking strength and the potential for damage—of how bad the earthquake effects were locally. The intensity level is what SideBar displays most prominently on the PC monitor. Intensity is shown as a large, colored bar that gets taller and changes color up a rainbow from blues toward reds as the shaking level increases. As opposed to earthquake magnitudes, which are reported as decimal values (like “7.6”), intensity is traditionally given as a Roman numeral, with “I” to “X+” assigned to levels of potential damage and perceived shaking strength. For good measure, SideBar shows the actual values of the force of shaking (peak ground acceleration as a percentage of gravity) and the speed of ground motion (peak ground velocity in inches per second, by default, or in centimeters per second, if you wish), both these values as decimal numbers. SideBar also remembers the most recent earthquakes (for up to one week), and can store as many of these previous earthquakes as the user allows (and as the user’s PC has room for)—typically thousands. SideBar also remembers forever the three largest earthquakes it has seen and all earthquakes over intensity IV so that one never loses particularly important events.

Stable heavy pentaquarks in constituent models

NASA Astrophysics Data System (ADS)

Richard, J.-M.; Valcarce, A.; Vijande, J.

2017-11-01

It is shown that standard constituent quark models produce (c bar cqqq) hidden-charm pentaquarks, where c denotes the charmed quark and q a light quark, which lie below the lowest threshold for spontaneous dissociation and thus are stable in the limit where the internal c bar c annihilation is neglected. The binding is a cooperative effect of the chromoelectric and chromomagnetic components of the interaction, and it disappears in the static limit with a pure chromoelectric potential. Their wave function contains color sextet and color octet configurations for the subsystems and can hardly be reduced to a molecular state made of two interacting hadrons. These pentaquark states could be searched for in the experiments having discovered or confirmed the hidden-charm meson and baryon resonances.

Symmetrical Taylor impact of glass bars

NASA Astrophysics Data System (ADS)

Murray, N. H.; Bourne, N. K.; Field, J. E.; Rosenberg, Z.

1998-07-01

Brar and Bless pioneered the use of plate impact upon bars as a technique for investigating the 1D stress loading of glass but limited their studies to relatively modest stresses (1). We wish to extend this technique by applying VISAR and embedded stress gauge measurements to a symmetrical version of the test in which two rods impact one upon the other. Previous work in the laboratory has characterised the glass types (soda-lime and borosilicate)(2). These experiments identify the failure mechanisms from high-speed photography and the stress and particle velocity histories are interpreted in the light of these results. The differences in response of the glasses and the relation of the fracture to the failure wave in uniaxial strain are discussed.

The GlueX DIRC detector

NASA Astrophysics Data System (ADS)

Barbosa, F.; Bessuille, J.; Chudakov, E.; Dzhygadlo, R.; Fanelli, C.; Frye, J.; Hardin, J.; Kelsey, J.; Patsyuk, M.; Schwarz, C.; Schwiening, J.; Stevens, J.; Shepherd, M.; Whitlatch, T.; Williams, M.

2017-12-01

The GlueX DIRC (Detection of Internally Reflected Cherenkov light) detector is being developed to upgrade the particle identification capabilities in the forward region of the GlueX experiment at Jefferson Lab. The GlueX DIRC will utilize four existing decommissioned BaBar DIRC bar boxes, which will be oriented to form a plane roughly 4 m away from the fixed target of the experiment. A new photon camera has been designed that is based on the SuperB FDIRC prototype. The full GlueX DIRC system will consist of two such cameras, with the first planned to be built and installed in 2017. We present the current status of the design and R&D, along with the future plans of the GlueX DIRC detector.

Performance and Results for Quartz Detector for the SuperHMS Spectrometer at Hall C Jefferson Lab

NASA Astrophysics Data System (ADS)

Griego, Benjamin F., Jr.

A quartz detector has been constructed to be part of the trigger system for the Super High Momentum Spectrometer (SHMS). The SHMS will play a pivotal role in carrying out the 12 -- GeV physics program at Hal -- C Jefferson Lab. The quartz hodoscope consists of twenty one fused silica bars. Each bar is 125 cm long, 5.5 cm wide, 2.5 cm thick, and is viewed by a UV -- sensitive PMT on each end. The quartz hodoscope's task is to provide a clean detection of charged particles, a high level of background suppression, and an accurate tracking efficiency determination. Initial test results of the quartz detectors which include light yield and position resolution will be presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soreq, Yotam; Zhu, Hua Xing; Zupan, Jure

We show that the normalized Higgs production p T and y h distributions are sensitive probes of Higgs couplings to light quarks. For up and/or down quark Yukawa couplings comparable to the SM b quark Yukawa themore » $$\\bar{u}u$$ or $$\\bar{d}d$$ fusion production of the Higgs could lead to appreciable softer p T distribution than in the SM. The rapidity distribution, on the other hand, becomes more forward. Here, we find that, owing partially to a downward fluctuation, one can derive competitive bounds on the two couplings using ATLAS measurements of normalized p T distribution at 8TeV. With 300 fb -1 at 13TeV LHC one could establish flavor non-universality of the Yukawa couplings in the down sector.« less

The austral peregrine falcon: Color variation, productivity, and pesticides

USGS Publications Warehouse

Ellis, D.H.

1985-01-01

The austral peregrine falcon (Falco peregrinus cassini) was studied in the Andean foot- hills and across the Patagonian steppe from November to December 1981. The birds under study (18 pairs) were reproducing at or near normal (pre-DDT) levels for other races. Pesticide residues, while elevated, were well below the values associated with reproductive failure in other populations. With one exception, eggshells were not abnormally thin. The peregrine falcon in Patagonia exhibits extreme color variation. Pallid birds are nearly pure white below (light cream as juveniles), whereas normally pigmented birds are black-crowned and conspicuously barred with black ventrally. Rare individuals of the Normal Phase display black heads, broad black ventral barring, and warm reddish-brown ventral background coloration.

Hybrid catadioptric system for advanced optical cavity velocimetry

DOEpatents

Frayer, Daniel K.

2018-02-06

A probe including reflector is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface by the probe and then reflected back from the surface, is Doppler shifted by the moving surface, collected into probe, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to one or more lens groups and a reflector, such as a parabolic reflector having a mirrored interior surface.

Developing LAr Scintillation Light Collection Ideas in the Short Baseline Neutrino Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szelc, A. M.

2016-02-08

Scintillation light is becoming the most rapidly developing feature of Liquid Argon Time Projection Chamber (LArTPC) neutrino detectors due to its capability to enhance and expand their physics reach traditionally based on charge readout. The SBND detector, set to be built on the Booster Neutrino Beam Line at Fermilab, is in a unique position to test novel liquid argon scintillation light readout systems in a detector with physics neutrino events. The different ideas under consideration by the collaboration are described, including an array of PMTs detecting direct light, SiPM coupled lightguide bars and a setup which uses PMTs/SiPMS and wavelengthmore » shifter covered reflector foils, as well as their respective strengths and physics foci and the benchmarks used to compare them.« less

14 CFR 91.209 - Aircraft lights.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Aircraft lights. 91.209 Section 91.209... Requirements § 91.209 Aircraft lights. No person may: (a) During the period from sunset to sunrise (or, in... position lights; (2) Park or move an aircraft in, or in dangerous proximity to, a night flight operations...

14 CFR 91.209 - Aircraft lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Aircraft lights. 91.209 Section 91.209... Requirements § 91.209 Aircraft lights. No person may: (a) During the period from sunset to sunrise (or, in... position lights; (2) Park or move an aircraft in, or in dangerous proximity to, a night flight operations...

14 CFR 91.209 - Aircraft lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Aircraft lights. 91.209 Section 91.209... Requirements § 91.209 Aircraft lights. No person may: (a) During the period from sunset to sunrise (or, in... position lights; (2) Park or move an aircraft in, or in dangerous proximity to, a night flight operations...

14 CFR 91.209 - Aircraft lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Aircraft lights. 91.209 Section 91.209... Requirements § 91.209 Aircraft lights. No person may: (a) During the period from sunset to sunrise (or, in... position lights; (2) Park or move an aircraft in, or in dangerous proximity to, a night flight operations...

14 CFR 91.209 - Aircraft lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Aircraft lights. 91.209 Section 91.209... Requirements § 91.209 Aircraft lights. No person may: (a) During the period from sunset to sunrise (or, in... position lights; (2) Park or move an aircraft in, or in dangerous proximity to, a night flight operations...

4D Light Field Imaging System Using Programmable Aperture

NASA Technical Reports Server (NTRS)

Bae, Youngsam

2012-01-01

Complete depth information can be extracted from analyzing all angles of light rays emanated from a source. However, this angular information is lost in a typical 2D imaging system. In order to record this information, a standard stereo imaging system uses two cameras to obtain information from two view angles. Sometimes, more cameras are used to obtain information from more angles. However, a 4D light field imaging technique can achieve this multiple-camera effect through a single-lens camera. Two methods are available for this: one using a microlens array, and the other using a moving aperture. The moving-aperture method can obtain more complete stereo information. The existing literature suggests a modified liquid crystal panel [LC (liquid crystal) panel, similar to ones commonly used in the display industry] to achieve a moving aperture. However, LC panels cannot withstand harsh environments and are not qualified for spaceflight. In this regard, different hardware is proposed for the moving aperture. A digital micromirror device (DMD) will replace the liquid crystal. This will be qualified for harsh environments for the 4D light field imaging. This will enable an imager to record near-complete stereo information. The approach to building a proof-ofconcept is using existing, or slightly modified, off-the-shelf components. An SLR (single-lens reflex) lens system, which typically has a large aperture for fast imaging, will be modified. The lens system will be arranged so that DMD can be integrated. The shape of aperture will be programmed for single-viewpoint imaging, multiple-viewpoint imaging, and coded aperture imaging. The novelty lies in using a DMD instead of a LC panel to move the apertures for 4D light field imaging. The DMD uses reflecting mirrors, so any light transmission lost (which would be expected from the LC panel) will be minimal. Also, the MEMS-based DMD can withstand higher temperature and pressure fluctuation than a LC panel can. Robotics need near complete stereo images for their autonomous navigation, manipulation, and depth approximation. The imaging system can provide visual feedback

Progress in reliable single emitters and laser bars for efficient CW-operation in the near-infrared emission range

NASA Astrophysics Data System (ADS)

Zorn, Martin; Hülsewede, Ralf; Pietrzak, Agnieszka; Meusel, Jens; Sebastian, Jürgen

2015-03-01

Laser bars, laser arrays, and single emitters are highly-desired light sources e.g. for direct material processing, pump sources for solid state and fiber lasers or medical applications. These sources require high output powers with optimal efficiency together with good reliability resulting in a long lifetime of the device. Desired wavelengths range from 760 nm in esthetic skin treatment over 915 nm, 940 nm and 976 nm to 1030 nm for direct material processing and pumping applications. In this publication we present our latest developments for the different application-defined wavelengths in continuouswave operation mode. At 760nm laser bars with 30 % filling factor and 1.5 mm resonator length show optical output powers around 90-100 W using an optimized design. For longer wavelengths between 915 nm and 1030 nm laser bars with 4 mm resonator length and 50 % filling factor show reliable output powers above 200 W. The efficiency reached lies above 60% and the slow axis divergence (95% power content) is below 7°. Further developments of bars tailored for 940 nm emission wavelength reach output powers of 350 W. Reliable single emitters for effective fiber coupling having emitter widths of 90 μm and 195 μm are presented. They emit optical powers of 12 W and 24 W, respectively, at emission wavelengths of 915 nm, 940 nm and 976 nm. Moreover, reliability tests of 90 μm-single emitters at a power level of 12W currently show a life time over 3500 h.

Building the Peanut: Simulations and Observations of Peanut-shaped Structures and Ansae in Face-on Disk Galaxies

NASA Astrophysics Data System (ADS)

Saha, Kanak; Graham, Alister W.; Rodríguez-Herranz, Isabel

2018-01-01

Peanut/x-shaped features observed in a significant fraction of disk galaxies are thought to have formed from vertically buckled bars. Despite being three-dimensional structures, they are preferentially detected in near edge-on projection. Only a few galaxies are found to have displayed such structures when their disks are relatively face-on—suggesting that either they are generally weak in face-on projection or many may be hidden by the light of their galaxy’s face-on disk. Here, we report on three (collisionless) simulated galaxies displaying peanut-shaped structures when their disks are seen both face-on and edge-on—resembling a three-dimensional peanut or dumbbell. Furthermore, these structures are accompanied by ansae and an outer ring at the end of the bar—as seen in real galaxies such as IC 5240. The same set of quantitative parameters used to measure peanut structures in real galaxies has been determined for the simulated galaxies, and a broad agreement is found. In addition, the peanut length grows in tandem with the bar, and is a maximum at half the length of the bar. Beyond the cutoff of these peanut structures, toward the end of the bar, we discover a new positive/negative feature in the B 6 radial profile associated with the isophotes of the ansae/ring. Our simulated, self-gravitating, three-dimensional peanut structures display cylindrical rotation even in the near-face-on disk projection. In addition, we report on a kinematic pinch in the velocity map along the bar minor axis, matching that seen in the surface density map.

Characterization of galactic bars from 3.6 μm S4G imaging

NASA Astrophysics Data System (ADS)

Díaz-García, S.; Salo, H.; Laurikainen, E.; Herrera-Endoqui, M.

2016-03-01

Context. Stellar bars play an essential role in the secular evolution of disk galaxies because they are responsible for the redistribution of matter and angular momentum. Dynamical models predict that bars become stronger and longer in time, while their rotation speed slows down. Aims: We use the Spitzer Survey of Stellar Structure in Galaxies (S4G) 3.6 μm imaging to study the properties (length and strength) and fraction of bars at z = 0 over a wide range of galaxy masses (M∗ ≈ 108-1011 M⊙) and Hubble types (-3 ≤ T ≤ 10). Methods: We calculated gravitational forces from the 3.6 μm images for galaxies with a disk inclination lower than 65°. We used the maximum of the tangential-to-radial force ratio in the bar region (Qb) as a measure of the bar-induced perturbation strength for a sample of ~600 barred galaxies. We also used the maximum of the normalized m = 2 Fourier density amplitude (A2max) to characterize the bar. Bar sizes were estimated I) visually; II) from ellipse fitting; III) from the radii of the strongest torque; and iv) from the radii of the largest m = 2 Fourier amplitude in the bar region. By combining our force calculations with the H I kinematics from the literature, we estimated the ratio of the halo-to-stellar mass (Mh/M∗) within the optical disk and by further using the universal rotation curve models, we obtained a first-order model of the rotation curve decomposition of 1128 disk galaxies. Results: We probe possible sources of uncertainty in our Qb measurements: the assumed scale height and its radial variation, the influence of the spiral arms torques, the effect of non-stellar emission in the bar region, and the dilution of the bar forces by the dark matter halo (our models imply that only ~10% of the disks in our sample are maximal). We find that for early- and intermediate-type disks (-3 ≤ T< 5), the relatively modest influence of the dark matter halo leads to a systematic reduction of the mean Qb by about 10-15%, which is of the same order as the uncertainty associated with estimating the vertical scale height. The halo correction on Qb becomes important for later types, implying a reduction of ~20-25% for T = 7-10. Whether the halo correction is included or not, the mean Qb shows an increasing trend with T. However, the mean A2max decreases for lower mass late-type systems. These opposing trends are most likely related to the reduced force dilution by bulges when moving towards later type galaxies. Nevertheless, when treated separately, both the early- and late-type disk galaxies show a strong positive correlation between Qb and A2max. For spirals the mean ɛ ≈ 0.5 is nearly independent of T, but it drops among S0s (≈0.2). The Qb and ɛ show a relatively tight dependence, with only a slight difference between early and late disks. For spirals, all our bar strength indicators correlate with the bar length (scaled to isophotal size). Late-type bars are longer than previously found in the literature. The bar fraction shows a double-humped distribution in the Hubble sequence (~75% for Sab galaxies), with a local minimum at T = 4 (~40%), and it drops for M∗ ≲ 109.5-10 M⊙. If we use bar identification methods based on Fourier decomposition or ellipse fitting instead of the morphological classification, the bar fraction decreases by ~30-50% for late-type systems with T ≥ 5 and correlates with Mh/M∗. Our Mh/M∗ ratios agree well with studies based on weak lensing analysis, abundance matching, and halo occupation distribution methods, under the assumption that the halo inside the optical disk contributes roughly a constant fraction of the total halo mass (~4%). Conclusions: We find possible evidence for the growth of bars within a Hubble time; as (1) bars in early-type galaxies show larger density amplitudes and disk-relative sizes than their intermediate-type counterparts; and (2) long bars are typically strong. We also observe two clearly distinct types of bars, between early- and intermediate-type galaxies (T< 5) on one side, and the late-type systems on the other, based on the differences in the bar properties. Most likely this distinction is connected to the higher halo-to-stellar ratio that we observe in later types, which affects the disk stability properties. Full Tables A.1-A.3, the tabulated radial force profiles, and the rotation curve decomposition model of each individual galaxy are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/587/A160

Interaction of compass sensing and object-motion detection in the locust central complex.

PubMed

Bockhorst, Tobias; Homberg, Uwe

2017-07-01

Goal-directed behavior is often complicated by unpredictable events, such as the appearance of a predator during directed locomotion. This situation requires adaptive responses like evasive maneuvers followed by subsequent reorientation and course correction. Here we study the possible neural underpinnings of such a situation in an insect, the desert locust. As in other insects, its sense of spatial orientation strongly relies on the central complex, a group of midline brain neuropils. The central complex houses sky compass cells that signal the polarization plane of skylight and thus indicate the animal's steering direction relative to the sun. Most of these cells additionally respond to small moving objects that drive fast sensory-motor circuits for escape. Here we investigate how the presentation of a moving object influences activity of the neurons during compass signaling. Cells responded in one of two ways: in some neurons, responses to the moving object were simply added to the compass response that had adapted during continuous stimulation by stationary polarized light. By contrast, other neurons disadapted, i.e., regained their full compass response to polarized light, when a moving object was presented. We propose that the latter case could help to prepare for reorientation of the animal after escape. A neuronal network based on central-complex architecture can explain both responses by slight changes in the dynamics and amplitudes of adaptation to polarized light in CL columnar input neurons of the system. NEW & NOTEWORTHY Neurons of the central complex in several insects signal compass directions through sensitivity to the sky polarization pattern. In locusts, these neurons also respond to moving objects. We show here that during polarized-light presentation, responses to moving objects override their compass signaling or restore adapted inhibitory as well as excitatory compass responses. A network model is presented to explain the variations of these responses that likely serve to redirect flight or walking following evasive maneuvers. Copyright © 2017 the American Physiological Society.

Method and apparatus for testing a forward-moving strand

DOEpatents

Ducommun, Joel; Vulliens, Philippe

1980-01-01

In a method for testing a continuously forward-moving strand a light beam which passes along a plane that extends approximately perpendicularly to the longitudinal axis of the strand is introduced into the strand. The brightness value is measured on a place of the strand exterior which is distal from the light incidence place by means of at least one photoelectronic element disposed directly on the strand exterior and the measured result is evaluated in a gating circuit which is electrically connected to the photoelectronic element.

Turbulence- and particle-resolved modeling of self-formed channels

NASA Astrophysics Data System (ADS)

Schmeeckle, M. W.

2016-12-01

A numerical model is presented that combines a large eddy simulation (LES) of turbulent water motion and a discrete element method (DEM) simulation of all sediment particles forming a small alluvial river. All simulations are begun with a relatively narrow and deep channel and a constant body force is applied to the fluid. At very small applied force at the critical shear stress for sediment motion the channel becomes wider and shallower. Transport on the banks becomes very small with larger transport at the center of the channel. However, even the very small bank transport resulted in continued net downslope motion and channel widening; bedload diffusion from higher transport areas of the channel is not sufficient to counteract downslope transport. This simulation will be extended over much longer times to determine whether an equilibrium straight channel with transport is possible without varying the water discharge. Simulations at slightly higher fluid forcing results in the development of alternate bars. Particle size segregation occurs in all simulations at multiple scales. At the smallest scale, turbulent structures induce small scale depressions; larger particles preferentially move to lower elevations of the depressions. Sloping beds at banks and bars also increase size segregation. However, bar translation mixes segregated sediments. Granular modeling of river channels appears to be a fruitful method for testing and developing continuum ideas of channel pattern formation and size segregation.

Turbulence-and particle-resolved modeling of self-formed channels

NASA Astrophysics Data System (ADS)

Schmeeckle, M. W.

2017-12-01

A numerical model is presented that combines a large eddy simulation (LES) of turbulent water motion and a discrete element method (DEM) simulation of all sediment particles forming a small alluvial river. All simulations are begun with a relatively narrow and deep channel and a constant body force is applied to the fluid. At very small applied force at the critical shear stress for sediment motion the channel becomes wider and shallower. Transport on the banks becomes very small with larger transport at the center of the channel. However, even the very small bank transport resulted in continued net downslope motion and channel widening; bedload diffusion from higher transport areas of the channel is not sufficient to counteract downslope transport. This simulation will be extended over much longer times to determine whether an equilibrium straight channel with transport is possible without varying the water discharge. Simulations at slightly higher fluid forcing results in the development of alternate bars. Particle size segregation occurs in all simulations at multiple scales. At the smallest scale, turbulent structures induce small scale depressions; larger particles preferentially move to lower elevations of the depressions. Sloping beds at banks and bars also increase size segregation. However, bar translation mixes segregated sediments. Granular modeling of river channels appears to be a fruitful method for testing and developing continuum ideas of channel pattern formation and size segregation.

Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing

PubMed Central

de Alcantara, Naasson P.; da Silva, Felipe M.; Guimarães, Mateus T.; Pereira, Matheus D.

2015-01-01

This paper presents a theoretical and experimental study on the use of Eddy Current Testing (ECT) to evaluate corrosion processes in steel bars used in reinforced concrete structures. The paper presents the mathematical basis of the ECT sensor built by the authors; followed by a finite element analysis. The results obtained in the simulations are compared with those obtained in experimental tests performed by the authors. Effective resistances and inductances; voltage drops and phase angles of wound coil are calculated using both; simulated and experimental data; and demonstrate a strong correlation. The production of samples of corroded steel bars; by using an impressed current technique is also presented. The authors performed experimental tests in the laboratory using handmade sensors; and the corroded samples. In the tests four gauges; with five levels of loss-of-mass references for each one were used. The results are analyzed in the light of the loss-of-mass and show a strong linear behavior for the analyzed parameters. The conclusions emphasize the feasibility of the proposed technique and highlight opportunities for future works. PMID:26712754

Nd:YLF laser for airborne/spaceborne laser ranging

NASA Technical Reports Server (NTRS)

Dallas, Joseph L.; Selker, Mark D.

1993-01-01

In order to meet the need for light weight, long lifetime, efficient, short pulse lasers, a diode-pumped, Nd:YLF oscillator and regenerative amplifier is being developed. The anticipated output is 20 mJ per 10 picosecond pulse, running at a repetition rate of 40 Hz. The fundamental wavelength is at 1047 nm. The oscillator is pumped by a single laser diode bar and mode locked using an electro-optic, intra-cavity phase modulator. The output from the oscillator is injected as a seed into the regenerative amplifier. The regenerative amplifier laser crystal is optically pumped by two 60W quasi-cw laser diode bars. Each diode is collimated using a custom designed micro-lens bar. The injected 10 ps pulse from the oscillator is kept circulating within the regenerative amplifier until this nanojoule level seed pulse is amplified to 2-3 millijoules. At this point the pulse is ejected and sent on to a more standard single pass amplifier where the energy is boosted to 20 mJ. The footprint of the entire laser (oscillator-regenerative amplifier-amplifier) will fit on a 3 by 4 ft. optical pallet.

Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing.

PubMed

de Alcantara, Naasson P; da Silva, Felipe M; Guimarães, Mateus T; Pereira, Matheus D

2015-12-24

This paper presents a theoretical and experimental study on the use of Eddy Current Testing (ECT) to evaluate corrosion processes in steel bars used in reinforced concrete structures. The paper presents the mathematical basis of the ECT sensor built by the authors; followed by a finite element analysis. The results obtained in the simulations are compared with those obtained in experimental tests performed by the authors. Effective resistances and inductances; voltage drops and phase angles of wound coil are calculated using both; simulated and experimental data; and demonstrate a strong correlation. The production of samples of corroded steel bars; by using an impressed current technique is also presented. The authors performed experimental tests in the laboratory using handmade sensors; and the corroded samples. In the tests four gauges; with five levels of loss-of-mass references for each one were used. The results are analyzed in the light of the loss-of-mass and show a strong linear behavior for the analyzed parameters. The conclusions emphasize the feasibility of the proposed technique and highlight opportunities for future works.

HUBBLE UNVEILS A GALAXY IN LIVING COLOR

NASA Technical Reports Server (NTRS)

2002-01-01

In this view of the center of the magnificent barred spiral galaxy NGC 1512, NASA Hubble Space Telescope's broad spectral vision reveals the galaxy at all wavelengths from ultraviolet to infrared. The colors (which indicate differences in light intensity) map where newly born star clusters exist in both 'dusty' and 'clean' regions of the galaxy. This color-composite image was created from seven images taken with three different Hubble cameras: the Faint Object Camera (FOC), the Wide Field and Planetary Camera 2 (WFPC2), and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). NGC 1512 is a barred spiral galaxy in the southern constellation of Horologium. Located 30 million light-years away, relatively 'nearby' as galaxies go, it is bright enough to be seen with amateur telescopes. The galaxy spans 70,000 light-years, nearly as much as our own Milky Way galaxy. The galaxy's core is unique for its stunning 2,400 light-year-wide circle of infant star clusters, called a 'circumnuclear' starburst ring. Starbursts are episodes of vigorous formation of new stars and are found in a variety of galaxy environments. Taking advantage of Hubble's sharp vision, as well as its unique wavelength coverage, a team of Israeli and American astronomers performed one of the broadest and most detailed studies ever of such star-forming regions. The results, which will be published in the June issue of the Astronomical Journal, show that in NGC 1512 newly born star clusters exist in both dusty and clean environments. The clean clusters are readily seen in ultraviolet and visible light, appearing as bright, blue clumps in the image. However, the dusty clusters are revealed only by the glow of the gas clouds in which they are hidden, as detected in red and infrared wavelengths by the Hubble cameras. This glow can be seen as red light permeating the dark, dusty lanes in the ring. 'The dust obscuration of clusters appears to be an on-off phenomenon,' says Dan Maoz, who headed the collaboration. 'The clusters are either completely hidden, enshrouded in their birth clouds, or almost completely exposed.' The scientists believe that stellar winds and powerful radiation from the bright, newly born stars have cleared away the original natal dust cloud in a fast and efficient 'cleansing' process. Aaron Barth, a co-investigator on the team, adds: 'It is remarkable how similar the properties of this starburst are to those of other nearby starbursts that have been studied in detail with Hubble.' This similarity gives the astronomers the hope that, by understanding the processes occurring in nearby galaxies, they can better interpret observations of very distant and faint starburst galaxies. Such distant galaxies formed the first generations of stars, when the universe was a fraction of its current age. Circumstellar star-forming rings are common in the universe. Such rings within barred spiral galaxies may in fact comprise the most numerous class of nearby starburst regions. Astronomers generally believe that the giant bar funnels the gas to the inner ring, where stars are formed within numerous star clusters. Studies like this one emphasize the need to observe at many different wavelengths to get the full picture of the processes taking place.

Effects of fluid viscosity on a moving sonoluminescing bubble.

PubMed

Sadighi-Bonabi, Rasoul; Mirheydari, Mona; Rezaee, Nastaran; Ebrahimi, Homa

2011-08-01

Based on the quasi-adiabatic model, the parameters of the bubble interior for a moving single bubble sonoluminescence in water, adiponitrile, and N-methylformamide are calculated for various fluid viscosities. By using a complete form of the hydrodynamic force, the bubble trajectory is calculated for a moving single bubble sonoluminescence (m-SBSL). It is found that as the fluid viscosity increases, the unique circular path changes to an ellipsoidal and then linear form and along this incrementally increase of viscosity the light intensity increases. By using the Bremsstrahlung model to describe the bubble radiation, gradual increase of the viscosity results in brighter emissions. It is found that in fluids with higher viscosity the light intensity decreases as time passes.

A search for resonances decaying into a Higgs boson and a new particle X in the XH → qqbb final state with the ATLAS detector

DOE PAGES

Aaboud, M.; Aad, G.; Abbott, B.; ...

2018-04-10

In this paper, a search for heavy resonances decaying into a Higgs boson (H) and a new particle (X) is reported, utilizing 36.1 fb -1 of proton–proton collision data atmore » $$\\sqrt{s}$$ = 13 TeV collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle X is assumed to decay to a pair of light quarks, and the fully hadronic final state XH → $$q\\bar{q}$$'$$b\\bar{b}$$ is analysed. The search considers the regime of high XH resonance masses, where the X and H bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large radius parameter. A two-dimensional phase space of XH mass versus X mass is scanned for evidence of a signal, over a range of XH resonance mass values between 1 TeV and 4 TeV, and for X particles with masses from 50 GeV to 1000 GeV. All search results are consistent with the expectations for the background due to Standard Model processes, and 95% CL upper limits are set, as a function of XH and X masses, on the production cross-section of the XH → $$q\\bar{q}$$'$$b\\bar{b}$$ resonance.« less

THE VERTICAL X-SHAPED STRUCTURE IN THE MILKY WAY: EVIDENCE FROM A SIMPLE BOXY BULGE MODEL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Zhaoyu; Shen Juntai, E-mail: jshen@shao.ac.cn

2012-09-20

A vertical X-shaped structure in the Galactic bulge was recently reported. Here, we present evidence of a similar X-shaped structure in the Shen et al. 2010 bar/boxy bulge model that simultaneously matches the stellar kinematics successfully. The X-shaped structure is found in the central region of our bar/boxy bulge model and is qualitatively consistent with the observed one in many aspects. End-to-end separations of the X-shaped structure in the radial and vertical directions are roughly 3 kpc and 1.8 kpc, respectively. The X-shaped structure contains about 7% of light in the boxy bulge region, but it is significant enough tomore » be identified in observations. An X-shaped structure naturally arises in the formation of bar/boxy bulges and is mainly associated with orbits trapped around the vertically extended x{sub 1} family. Like the bar in our model, the X-shaped structure tilts away from the Sun-Galactic center line by 20 Degree-Sign . The X-shaped structure becomes increasingly symmetric about the disk plane, so the observed symmetry may indicate that it formed at least a few billion years ago. The existence of the vertical X-shaped structure suggests that the formation of the Milky Way bulge is shaped mainly by internal disk dynamical instabilities.« less

A search for resonances decaying into a Higgs boson and a new particle X in the XH → qqbb final state with the ATLAS detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aaboud, M.; Aad, G.; Abbott, B.

In this paper, a search for heavy resonances decaying into a Higgs boson (H) and a new particle (X) is reported, utilizing 36.1 fb -1 of proton–proton collision data atmore » $$\\sqrt{s}$$ = 13 TeV collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle X is assumed to decay to a pair of light quarks, and the fully hadronic final state XH → $$q\\bar{q}$$'$$b\\bar{b}$$ is analysed. The search considers the regime of high XH resonance masses, where the X and H bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large radius parameter. A two-dimensional phase space of XH mass versus X mass is scanned for evidence of a signal, over a range of XH resonance mass values between 1 TeV and 4 TeV, and for X particles with masses from 50 GeV to 1000 GeV. All search results are consistent with the expectations for the background due to Standard Model processes, and 95% CL upper limits are set, as a function of XH and X masses, on the production cross-section of the XH → $$q\\bar{q}$$'$$b\\bar{b}$$ resonance.« less

The bar-halo interaction - I. From fundamental dynamics to revised N-body requirements

NASA Astrophysics Data System (ADS)

Weinberg, Martin D.; Katz, Neal

2007-02-01

A galaxy remains near equilibrium for most of its history. Only through resonances can non-axisymmetric features, such as spiral arms and bars, exert torques over large scales and change the overall structure of the galaxy. In this paper, we describe the resonant interaction mechanism in detail, derive explicit criteria for the particle number required to simulate these dynamical processes accurately using N-body simulations, and illustrate them with numerical experiments. To do this, we perform a direct numerical solution of perturbation theory, in short, by solving for each orbit in an ensemble and make detailed comparisons with N-body simulations. The criteria include: sufficient particle coverage in phase space near the resonance and enough particles to minimize gravitational potential fluctuations that will change the dynamics of the resonant encounter. These criteria are general in concept and can be applied to any dynamical interaction. We use the bar-halo interaction as our primary example owing to its technical simplicity and astronomical ubiquity. Some of our more surprising findings are as follows. First, the inner Lindblad like resonance, responsible for coupling the bar to the central halo cusp, requires more than equal-mass particles within the virial radius or inside the bar radius for a Milky Way like bar in a Navarro, Frenk & White profile. Secondly, orbits that linger near the resonance receive more angular momentum than orbits that move through the resonance quickly. Small-scale fluctuations present in state-of-the-art particle-particle simulations can knock orbits out of resonance, preventing them from lingering and, thereby, decrease the torque per orbit. This can be offset by the larger number of orbits affected by the resonance due to the diffusion. However, noise from orbiting substructure remains at least an order of magnitude too small to be of consequence. Applied to N-body simulations, the required particle numbers are sufficiently high for scenarios of interest that apparent convergence in particle number is misleading: the convergence with N may still be in the noise-dominated regime. State-of-the-art simulations are not adequate to follow all aspects of secular evolution driven by the bar-halo interaction. It is not possible to derive particle number requirements that apply to all situations, for example, more subtle interactions may be even more difficult to simulate. Therefore, we present a procedure to test the requirements for individual N-body codes to the actual problem of interest.

A Toxoplasma gondii Class XIV Myosin, Expressed in Sf9 Cells with a Parasite Co-chaperone, Requires Two Light Chains for Fast Motility*

PubMed Central

Bookwalter, Carol S.; Kelsen, Anne; Leung, Jacqueline M.; Ward, Gary E.; Trybus, Kathleen M.

2014-01-01

Many diverse myosin classes can be expressed using the baculovirus/Sf9 insect cell expression system, whereas others have been recalcitrant. We hypothesized that most myosins utilize Sf9 cell chaperones, but others require an organism-specific co-chaperone. TgMyoA, a class XIVa myosin from the parasite Toxoplasma gondii, is required for the parasite to efficiently move and invade host cells. The T. gondii genome contains one UCS family myosin co-chaperone (TgUNC). TgMyoA expressed in Sf9 cells was soluble and functional only if the heavy and light chain(s) were co-expressed with TgUNC. The tetratricopeptide repeat domain of TgUNC was not essential to obtain functional myosin, implying that there are other mechanisms to recruit Hsp90. Purified TgMyoA heavy chain complexed with its regulatory light chain (TgMLC1) moved actin in a motility assay at a speed of ∼1.5 μm/s. When a putative essential light chain (TgELC1) was also bound, TgMyoA moved actin at more than twice that speed (∼3.4 μm/s). This result implies that two light chains bind to and stabilize the lever arm, the domain that amplifies small motions at the active site into the larger motions that propel actin at fast speeds. Our results show that the TgMyoA domain structure is more similar to other myosins than previously appreciated and provide a molecular explanation for how it moves actin at fast speeds. The ability to express milligram quantities of a class XIV myosin in a heterologous system paves the way for detailed structure-function analysis of TgMyoA and identification of small molecule inhibitors. PMID:25231988

Phosphor thermometry system

DOEpatents

Beshears, David L.; Sitter, Jr., David N.; Andrews, William H.; Simpson, Marc L.; Abston, Ruth A.; Cates, Michael R.; Allison, Steve W.

2000-01-01

An apparatus for measuring the temperature of a moving substrate includes an air gun with a powder inlet port in communication with the outlet port of a powder reservoir, an air inlet port in communication with a pressurized air source, and an outlet nozzle spaced from and directed toward the moving substrate. The air gun is activated by the air pulses to spray controlled amounts of the powdered phosphor onto the moving substrate, where the phosphor assumes the temperature of the moving substrate. A laser produces light pulses, and optics direct the light pulses onto the phosphor on the moving substrate, in response to which the phosphor emits a luminescence with a decay rate indicative of the temperature of the phosphor. A collection lens is disposed to focus the luminescence, and a photodetector detects the luminescence focused by the collection lens and produces an electrical signal that is characteristic of the brightness of the luminescence. A processor analyzes the electrical signal to determine the decay characteristic of the luminescence and to determine the temperature of the phosphor from the decay characteristic.

Effect of parameters in moving average method for event detection enhancement using phase sensitive OTDR

NASA Astrophysics Data System (ADS)

Kwon, Yong-Seok; Naeem, Khurram; Jeon, Min Yong; Kwon, Il-bum

2017-04-01

We analyze the relations of parameters in moving average method to enhance the event detectability of phase sensitive optical time domain reflectometer (OTDR). If the external events have unique frequency of vibration, then the control parameters of moving average method should be optimized in order to detect these events efficiently. A phase sensitive OTDR was implemented by a pulsed light source, which is composed of a laser diode, a semiconductor optical amplifier, an erbium-doped fiber amplifier, a fiber Bragg grating filter, and a light receiving part, which has a photo-detector and high speed data acquisition system. The moving average method is operated with the control parameters: total number of raw traces, M, number of averaged traces, N, and step size of moving, n. The raw traces are obtained by the phase sensitive OTDR with sound signals generated by a speaker. Using these trace data, the relation of the control parameters is analyzed. In the result, if the event signal has one frequency, then the optimal values of N, n are existed to detect the event efficiently.

Continuing Studies of Planetary Atmospheres Associated with Experiments on the Galileo Jupiter Probe and Infrared Observations of Venus

NASA Technical Reports Server (NTRS)

Ragent, Boris

1998-01-01

The results of the nephelometer experiment conducted aboard the Probe of the Galileo mission to Jupiter are presented. The tenuous clouds and sparse particulate matter in the relatively particle-free 5-micron "hot spot" region of the Probe's descent were documented from about 0.46 bars to about 12 bars. Three regions of apparent coherent structure were noted, in addition to many indications of extremely small particle concentrations along the descent path. From the first valid measurement at about 0.46 bars down to about 0.55 bars a feeble decaying lower portion of a cloud, corresponding with the predicted ammonia particle cloud, was encountered. A denser, but still very modest, particle structure was present in the pressure regime extending from about 0.76 to a distinctive base at 1.34 bars, and is compatible with the expected ammonium hydrosulfide cloud. No massive water cloud was encountered, although below the second structure, a small, vertically thin layer at about 1.65 bars may be detached from the cloud above, but may also be water condensation, compatible with reported measurements of water abundance from other Galileo Mission experiments. A third small signal region, extending from about 1.9 to 4.5 bars, exhibited quite weak but still distinctive structure, and, although the identification of the light scatterers in this region is uncertain, may also be a water cloud perhaps associated with lateral atmospheric motion and/or reduced to a small mass density by atmospheric subsidence or other explanations. Rough descriptions of the particle size distributions and cloud properties in these regions have been derived, although they may be imprecise because of the small signals and experimental difficulties. These descriptions document the small number densities of particles, the moderate particle sizes, generally in the slightly submicron to few micron range, and the resulting small optical depths, mass densities due to particles, column particle number loading and column mass loading in the atmosphere encountered by the Galileo Probe during its descent.

Continuing Studies of Planetary Atmospheres Associated With Experiments on the Galileo Jupiter Probe and Infrared Observations of Venus

NASA Technical Reports Server (NTRS)

Goodman,Jindra; Ragent, Boris

1998-01-01

The results of the nephelometer experiment conducted aboard the Probe of the Galileo mission to Jupiter are presented. The tenuous clouds and sparse particulate matter in the relatively particle-free 5-micron "hot spot" region of the Probe's descent were documented from about 0.46 bars to about 12 bars. Three regions of apparent coherent structure were noted, in addition to many indications of extremely small particle concentrations along the descent path. From the first valid measurement at about 0.46 bars down to about 0.55 bars a feeble decaying lower portion of a cloud, corresponding with the predicted ammonia particle cloud, was encountered. A denser, but still very modest, particle structure was present in the pressure regime extending from about 0.76 to a distinctive base at 1.34 bars, and is compatible with the expected ammonium hydrosulfide cloud. No massive water cloud was encountered, although below the second structure, a small, vertically thin layer at about 1.65 bars may be detached from the cloud above, but may also be water condensation, compatible with reported measurements of water abundance from other Galileo Mission experiments. A third small signal region, extending from about 1.9 to 4.5 bars, exhibited quite weak but still distinctive structure, and, although the identification of the light scatterers in this region is uncertain, may also be a water cloud perhaps associated with lateral atmospheric motion and/or reduced to a small mass density by atmospheric subsidence or other explanations. Rough descriptions of the particle size distributions and cloud properties in these regions have been derived, although they may be imprecise because of the small signals and experimental difficulties. These descriptions document the small number densities of particles, the moderate particle sizes, generally in the slightly submicron to few micron range, and the resulting small optical depths, mass densities due to particles, column particle number loading and column mass loading in the atmosphere encountered by the Galileo Probe during its descent.

Taylor impact of glass bars

NASA Astrophysics Data System (ADS)

Murray, Natalie; Bourne, Neil; Field, John

1997-07-01

Brar and Bless pioneeered the use of plate impact upon bars as a technique for investigating the 1D stress loading of glass. We wish to extend this technique by applying VISAR and embedded stress gauge measurements to a symmetrical version of the test. In this configuration two rods impact one upon the other in a symmetrical version of the Taylor test geometry in which the impact is perfectly rigid in the centre of mass frame. Previous work in the laboratory has characterised the three glass types (float, borosilicate and a high density lead glass). These experiments will identify the 1D stress failure mechanisms from high-speed photography and the stress and particle velocity histories will be interpreted in the light of these results. The differences in response of the three glasses will be highlighted.

Surfactant antimony enhanced indium incorporation on InGaN (000 1 bar) surface: A DFT study

NASA Astrophysics Data System (ADS)

Zhang, Yiou; Zhu, Junyi

2016-03-01

InGaN is an ideal alloy system for optoelectronic devices due its tunable band gap. Yet high-quality InGaN requires high In concentration, which is a challenging issue that limits its use in green-light LEDs and other devices. In this paper, we investigated the surfactant effect of Sb on the In incorporation on InGaN (000 1 bar) surface via first-principles approaches. Surface phase diagram was also constructed to determine surface structures under different growth conditions. By analyzing surface stress under different structures, we found that Sb adatom can induce tensile sites in the cation layer, enhancing the In incorporation. These findings may provide fundamental understandings and guidelines for the growth of InGaN with high In concentration.

The GlueX DIRC detector

DOE PAGES

Barbosa, F.; Bessuille, J.; Chudakov, E.; ...

2017-02-03

We present the GlueX DIRC (Detection of Internally Reflected Cherenkov light) detector that is being developed to upgrade the particle identification capabilities in the forward region of the GlueX experiment at Jefferson Lab. The GlueX DIRC will utilize four existing decommissioned BaBar DIRC bar boxes, which will be oriented to form a plane roughly 4 m away from the fixed target of the experiment. A new photon camera has been designed that is based on the SuperB FDIRC prototype. The full GlueX DIRC system will consist of two such cameras, with the first planned to be built and installed inmore » 2017. In addition, we present the current status of the design and R&D, along with the future plans of the GlueX DIRC detector.« less

The DIRC front-end electronics chain for BaBar

NASA Astrophysics Data System (ADS)

Bailly, P.; Chauveau, J.; Del Buono, L.; Genat, J. F.; Lebbolo, H.; Roos, L.; Zhang, B.; Beigbeder, C.; Bernier, R.; Breton, D.; Caceres, T.; Chase, R.; Ducorps, A.; Hrisoho, A.; Imbert, P.; Sen, S.; Tocut, V.; Truong, K.; Wormser, G.; Zomer, F.; Bonneaud, G.; Dohou, F.; Gastaldi, F.; Matricon, P.; Renard, C.; Thiebaux, C.; Vasileiadis, G.; Verderi, M.; Oxoby, G.; Va'Vra, J.; Warner, D.; Wilson, R. J.

1999-08-01

The detector of Internally Reflected Cherenkov light (DIRC) of the BaBar detector (SLAC Stanford, USA) measures better than 1 ns the arrival time of Cherenkov photoelectrons, detected in a 11 000 phototubes array and their amplitude spectra. It mainly comprises of 64-channel DIRC Front-End Boards (DFB) equipped with eight full-custom Analog chips performing zero-cross discrimination with 2 mV threshold and pulse shaping, four full-custom Digital TDC chips for timing measurements with 500 ps binning and a readout logic selecting hits in the trigger window, and DIRC Crate Controller cards (DCC) serializing the data collected from up to 16 DFBs onto a 1.2 Gb/s optical link. Extensive test of the pre-production chips have been performed as well as system tests.

Radiation Blocking Lenses

NASA Technical Reports Server (NTRS)

1989-01-01

Biomedical Optical Company of America's (BOCA) suntiger lenses, similar in principle to natural filters in the eyes of hawks and eagles, bar 99 percent of potentially harmful wavelengths, while allowing visually useful colors of light (red, orange, green) to pass through. They also improve visual acuity, night vision and haze or fog visibility. The lenses evolved from work done by James B. Stephens and Dr. Charles G. Miller of the Jet Propulsion Laboratory. They developed a formula and produced a commercial welding curtain that absorbs, filters, and scatters light. This research led to protective glasses now used by dentists, workers in hazardous environments, CRT operators and skiers.

Sediment storage time in a simulated meandering river's floodplain, comparisons of point bar and overbank deposits

NASA Astrophysics Data System (ADS)

Ackerman, T. R.; Pizzuto, J. E.

2016-12-01

Sediment may be stored briefly or for long periods in alluvial deposits adjacent to rivers. The duration of sediment storage may affect diagenesis, and controls the timing of sediment delivery, affecting the propagation of upland sediment signals caused by tectonics, climate change, and land use, and the efficacy of watershed management strategies designed to reduce sediment loading to estuaries and reservoirs. Understanding the functional form of storage time distributions can help to extrapolate from limited field observations and improve forecasts of sediment loading. We simulate stratigraphy adjacent to a modeled river where meander migration is driven by channel curvature. The basal unit is built immediately as the channel migrates away, analogous to a point bar; rules for overbank (flood) deposition create thicker deposits at low elevations and near the channel, forming topographic features analogous to natural levees, scroll bars, and terraces. Deposit age is tracked everywhere throughout the simulation, and the storage time is recorded when the channel returns and erodes the sediment at each pixel. 210 ky of simulated run time is sufficient for the channel to migrate 10,500 channel widths, but only the final 90 ky are analyzed. Storage time survivor functions are well fit by exponential functions until 500 years (point bar) or 600 years (overbank) representing the youngest 50% of eroded sediment. Then (until an age of 12 ky, representing the next 48% (point bar) or 45% (overbank) of eroding sediment), the distributions are well fit by heavy tailed power functions with slopes of -1 (point bar) and -0.75 (overbank). After 12 ky (6% of model run time) the remainder of the storage time distributions become exponential (light tailed). Point bar sediment has the greatest chance (6%) of eroding at 120 years, as the river reworks recently deposited point bars. Overbank sediment has an 8% chance of eroding after 1 time step, a chance that declines by half after 3 time steps. The high probability of eroding young overbank deposits occurs as the river reworks recently formed natural levees. These results show that depositional environment affects river floodplain storage times shorter than a few centuries, and suggest that a power law distribution with a truncated tail may be the most reasonable functional fit.

Development of the auto-steering software and equipment technology (ASSET)

NASA Astrophysics Data System (ADS)

McKay, Mark D.; Anderson, Matthew O.; Wadsworth, Derek C.

2003-09-01

The Idaho National Engineering and Environmental Laboratory (INEEL), through collaboration with INSAT Co., has developed a low cost robotic auto-steering system for parallel contour swathing. The capability to perform parallel contour swathing while minimizing "skip" and "overlap" is a necessity for cost-effective crop management within precision agriculture. Current methods for performing parallel contour swathing consist of using a Differential Global Position System (DGPS) coupled with a light bar system to prompt an operator where to steer. The complexity of operating heavy equipment, ensuring proper chemical mixture and application, and steering to a light bar indicator can be overwhelming to an operator. To simplify these tasks, an inexpensive robotic steering system has been developed and tested on several farming implements. This development leveraged research conducted by the INEEL and Utah State University. The INEEL-INSAT Auto-Steering Software and Equipment Technology provides the following: 1) the ability to drive in a straight line within +/- 2 feet while traveling at least 15 mph, 2) interfaces to a Real Time Kinematic (RTK) DGPS and sub-meter DGPS, 3) safety features such as Emergency-stop, steering wheel deactivation, computer watchdog deactivation, etc., and 4) a low-cost, field-ready system that is easily adapted to other systems.

INTERGALACTIC 'PIPELINE' FUNNELS MATTER BETWEEN COLLIDING GALAXIES

NASA Technical Reports Server (NTRS)

2002-01-01

This visible-light picture, taken by NASA's Hubble Space Telescope, reveals an intergalactic 'pipeline' of material flowing between two battered galaxies that bumped into each other about 100 million years ago. The pipeline [the dark string of matter] begins in NGC 1410 [the galaxy at left], crosses over 20,000 light-years of intergalactic space, and wraps around NGC 1409 [the companion galaxy at right] like a ribbon around a package. Although astronomers have taken many stunning pictures of galaxies slamming into each other, this image represents the clearest view of how some interacting galaxies dump material onto their companions. These results are being presented today at the 197th meeting of the American Astronomical Society in San Diego, CA. Astronomers used the Space Telescope Imaging Spectrograph to confirm that the pipeline is a continuous string of material linking both galaxies. Scientists believe that the tussle between these compact galaxies somehow created the pipeline, but they're not certain why NGC 1409 was the one to begin gravitationally siphoning material from its partner. And they don't know where the pipeline begins in NGC 1410. More perplexing to astronomers is that NGC 1409 is seemingly unaware that it is gobbling up a steady flow of material. A stream of matter funneling into the galaxy should have fueled a spate of star birth. But astronomers don't see it. They speculate that the gas flowing into NGC 1409 is too hot to gravitationally collapse and form stars. Astronomers also believe that the pipeline itself may contribute to the star-forming draught. The pipeline, a pencil-thin, 500 light-year-wide string of material, is moving a mere 0.02 solar masses of matter a year. Astronomers estimate that NGC 1409 has consumed only about a million solar masses of gas and dust, which is not enough material to spawn some of the star-forming regions seen in our Milky Way. The low amount means that there may not be enough material to ignite star birth in NGC 1409, either. The glancing blow between the galaxies was enough, however, to toss stars deep into space and ignite a rash of star birth in NGC 1410. The arms of NGC 1410, an active, gas-rich spiral galaxy classified as a Seyfert, are awash in blue, the signature color of star-forming regions. The bar of material bisecting the center of NGC 1409 also is a typical byproduct of galaxy collisions. Astronomers expect more fireworks to come. The galaxies are doomed to continue their game of 'bumper cars,' hitting each other and moving apart several times until finally merging in another 200 million years. The galaxies' centers are only 23,000 light-years apart, which is slightly less than Earth's distance from the center of the Milky Way. They are bound together by gravity, orbiting each other at 670,000 miles an hour (1 million kilometers an hour). The galaxies reside about 300 million light-years from Earth in the constellation Taurus. The Hubble picture was taken Oct. 25, 1999. Credits: NASA, William C. Keel (University of Alabama, Tuscaloosa)

Optical sectioning microscopes with no moving parts using a micro-stripe array light emitting diode.

PubMed

Poher, V; Zhang, H X; Kennedy, G T; Griffin, C; Oddos, S; Gu, E; Elson, D S; Girkin, M; French, P M W; Dawson, M D; Neil, M A

2007-09-03

We describe an optical sectioning microscopy system with no moving parts based on a micro-structured stripe-array light emitting diode (LED). By projecting arbitrary line or grid patterns onto the object, we are able to implement a variety of optical sectioning microscopy techniques such as grid-projection structured illumination and line scanning confocal microscopy, switching from one imaging technique to another without modifying the microscope setup. The micro-structured LED and driver are detailed and depth discrimination capabilities are measured and calculated.

Spherical grating monochromator with interferometer control and in-vacuum reference

NASA Astrophysics Data System (ADS)

Holly, D. J.; Mason, W. P.; Sailor, T.; Smith, R. E.; Wahl, D.

2002-03-01

Physical Science Laboratory's new generation of spherical grating monochromators incorporates a laser interferometer to control scan angle and an in-vacuum absolute angle reference, as well as other improvements. The design accommodates up to six gratings which can be moved axially (under motor control, with encoder position readback) at any scan angle. The gratings are cooled by means of spring-loaded clamps which conduct heat to a water-cooled plate. The instruments feature hollow roller bearings on the scan axis to minimize bearing runout, and a pseudosine-bar drive for precise control of grating angle. The interferometer angle-measuring optics are mounted inside the vacuum chamber and measure the angle between the grating scan axis and the instrument's granite base. The laser interferometer measures the grating angle with a resolution of approximately 0.02 arcsec over the entire scan range of 40°. To provide a reference for the interferometer angle measurement, we have built an in-vacuum optical reference which uses custom chrome-on-glass reticles mounted inside the vacuum chamber. Collimated light from a source outside the vacuum passes through the reticles to yield quadrature signals which precisely define an absolute reference angle for the interferometer. Repeatability of the grating angle is within a range of ±0.05 arcsec. Two of these instruments are in operation at SRRC (Taiwan) and a third instrument has been delivered to NSLS (Brookhaven).

Calibration method for video and radiation imagers

DOEpatents

Cunningham, Mark F [Oak Ridge, TN; Fabris, Lorenzo [Knoxville, TN; Gee, Timothy F [Oak Ridge, TN; Goddard, Jr., James S.; Karnowski, Thomas P [Knoxville, TN; Ziock, Klaus-peter [Clinton, TN

2011-07-05

The relationship between the high energy radiation imager pixel (HERIP) coordinate and real-world x-coordinate is determined by a least square fit between the HERIP x-coordinate and the measured real-world x-coordinates of calibration markers that emit high energy radiation imager and reflect visible light. Upon calibration, a high energy radiation imager pixel position may be determined based on a real-world coordinate of a moving vehicle. Further, a scale parameter for said high energy radiation imager may be determined based on the real-world coordinate. The scale parameter depends on the y-coordinate of the moving vehicle as provided by a visible light camera. The high energy radiation imager may be employed to detect radiation from moving vehicles in multiple lanes, which correspondingly have different distances to the high energy radiation imager.

[Comparison of film-screen combinations in contrast-detail diagram and with interactive image analysis. 3: Trimodal histograms of gray scale distribution in bar groups of lead pattern images].

PubMed

Hagemann, G; Eichbaum, G; Stamm, G

1998-05-01

The following four screen film combinations were compared: a) a combination of anticrossover film and UV-light emitting screens, b) a combination of blue-light emitting screens and film and c) two conventional green fluorescing screen film combinations. Radiographs of a specially designed plexiglass phantom (0.2 x 0.2 x 0.12 m3) with bar patterns of lead and plaster and of air, respectively were obtained using the following parameters: 12 pulse generator, 0.6 mm focus size, 4.7 mm aluminum prefilter, a grid with 40 lines/cm (12:1) and a focus-detector distance of 1.15 m. Image analysis was performed using an Ibas system and a Zeiss Kontron computer. Display conditions were the following: display distance 0.12 m, a vario film objective 35/70 (Zeiss), a video camera tube with a PbO photocathode, 625 lines (Siemens Heimann), an Ibas image matrix of 512 x 512 pixels with a spatial resolution of ca. 7 cycles/mm, the projected matrix area was 5000 micron 2. Maxima in the histograms of a grouped bar pattern were estimated as mean values from the bar and gap regions ("mean value method"). They were used to calculate signal contrast, standard deviations of the means and scatter fraction. Comparing the histograms with respect to spatial resolution and kV setting a clear advantage of the UVR system becomes obvious. The quantitative analysis yielded a maximum spatial resolution of approx. 3 cycles/mm for the UVR system at 60 kV which decreased to half of this value at 117 kV caused by the increasing influence of scattered radiation. A ranking of screen-film systems with respect to image quality and dose requirement is presented. For its evaluation an interactive image analysis using the mean value method was found to be superior to signal/noise ratio measurements and visual analysis in respect to diagnostic relevance and saving of time.

Structure from Motion vs. the Kinect: Comparisons of River Field Measurements at the 10-2 to 102 meter Scales

NASA Astrophysics Data System (ADS)

Fonstad, M. A.; Dietrich, J. T.

2014-12-01

At the very smallest spatial scales of fluvial field analysis, measurements made historically in situ are often now supplemented, or even replaced by, remote sensing methods. This is particularly true in the case of topographic and particle size measurement. In the field, the scales of in situ observation usually range from millimeters up to hundreds of meters. Two recent approaches for remote mapping of river environments at the scales of historical in situ observations are (1) camera-based structure from motion (SfM), and (2) active patterned-light measurement with devices such as the Kinect. Even if only carried by hand, these two approaches can produce topographic datasets over three to four orders of magnitude of spatial scale. Which approach is most useful? Previous studies have demonstrated that both SfM and the Kinect are precise and accurate over in situ field measurement scales; we instead turn to alternate comparative metrics to help determine which tools might be best for our river measurement tasks. These metrics might include (1) the ease of field use, (2) which general environments are or are not amenable to measurement, (3) robustness to changing environmental conditions, (4) ease of data processing, and (5) cost. We test these metrics in a variety of bar-scale fluvial field environments, including a large-river cobble bar, a sand-bedded river point bar, and a complex mountain stream bar. The structure from motion approach is field-equipment inexpensive, is viable over a wide range of environmental conditions, and is highly spatially scalable. The approach requires some type of spatial referencing to make the data useful. The Kinect has the advantages of an almost real-time display of collected data, so problems can be detected quickly, being fast and easy to use, and the data are collected with arbitrary but metric coordinates, so absolute referencing isn't needed to use the data for many problems. It has the disadvantages of its light field generally being unable to penetrate water surfaces, becoming unusable in strong sunlight, and providing so much data as to be sometimes unwieldy in the data processing stage.

Salmonella penetration through eggshells of chickens of different genetic backgrounds.

PubMed

Rathgeber, Bruce M; McCarron, Paige; Budgell, Krista L

2013-09-01

Eggs have been identified as a source of salmonellosis, making the transmission of Salmonella to eggs of great concern to the poultry industry. The goal of this experiment was to determine the ability of Salmonella to penetrate the eggshell of 5 different breeds of noncommercial chicken, Barred Plymouth Rock, White Leghorn, Brown Leghorn, Fayoumi, and Light Sussex, and 1 commercial Lohmann LSL-Lite. Egg weight, breaking force, shell weight, and shell thickness measurements were taken for 30 eggs per breed. A 1 cm in diameter hole was cut out from the narrow end of 30 additional eggs per breed. The shells were filled with plate count agar containing tetracycline and 0.1% 2,3,5-triphenyl terazolium chloride and sealed with paraffin wax. Agar-filled eggs were submerged for 1 min in an overnight culture of tetracycline-resistant Salmonella Heidelberg and incubated at 37°C for 40 h. Eggs were candled and visual colonies were counted and reported as cfu per egg and cfu per gram of shell. The SAS mixed model was used to evaluate differences between breeds for egg quality characteristics and the number of cfu per egg and per gram of shell. Commercial layers (62.6 g) and Barred Plymouth Rock (61.5 g) produced the largest eggs, whereas Fayoumi (47.1 g) produced the smallest (P < 0.05). Force to break the shell was lowest (P < 0.05) for Barred Plymouth Rock (3.6 kg) and greatest for the commercial (4.4 kg), White Leghorn (4.4 kg), and Fayoumi (4.2 kg). Bacteria penetrating the shell was lowest (P < 0.05) for Barred Plymouth Rock (10.7 cfu/g) and highest for Light Sussex (27.7 cfu/g) and Brown Leghorn (27.2 cfu/g), with other breeds intermediate. These results indicate that there are breed-specific influences on the ability of an egg to resist Salmonella, which cannot be explained by shell quality measurements. Further investigations are warranted to determine the contributing factors to shell penetration by bacteria. This study highlights the value in maintaining heritage chicken breeds as a genetic resource for the future.

[Comparison of film-screen combination in a contrast detail diagram and with interactive image analysis. 1: Contrast detail diagram].

PubMed

Hagemann, G; Eichbaum, G

1997-07-01

The following three film-screen combinations were compared: a) a combination of anticrossover film and UV-light emitting screens, b) a combination of blue-light emitting screens and film, and c) a conventional green fluorescing screen film combination. Radiographs of a specially designed plexiglass phantom (0.2 x 0.2 x 0.12 m3) were obtained that contained bar patterns of lead and plaster (calcium sulfate) to test high and intermediate contrast resolution and bar patterns of air to test low contrast resolution, respectively. An aluminum step wedge was integrated to evaluate dose-density curves of the radiographs. The dose values for the various step thicknesses were measured as percentage of the dose value in air for 60, 81, and 117 kV. Exposure conditions were the following: 12 pulse generator, 0.6 mm focus size, 4.7 mm aluminum prefilter, a grid with 40 lines/cm (12:1), and a focus-detector distance of 1.15 m. The thresholds of visible bars of the various pattern materials were assessed by seven radiologists, one technician, and the authors. The resulting contrast detail diagram could not prove any significant differences between the three tested screen film combinations. The pairwise comparison, however, found 8 of the 18 paired differences to be statistically significant between the conventional and the two new screen-film combinations. The authors concluded that subjective visual assessment of the threshold in a contrast detail study alone is of only limited value to grade image quality if no well-defined criteria are used (BIR report 20 [1989] 137-139). The statistical approach of paired differences of the estimated means appeared to be more appropriate.

Hubble Sees Galaxies Spiraling around Leo

NASA Image and Video Library

2014-04-18

Shown here is a spiral galaxy known as NGC 3455, which lies some 65 million light-years away from us in the constellation of Leo (the Lion). Galaxies are classified into different types according to their structure and appearance. This classification system is known as the Hubble Sequence, named after its creator Edwin Hubble. In this image released 14, April, 2014, NGC 3455 is known as a type SB galaxy — a barred spiral. Barred spiral galaxies account for approximately two thirds of all spirals. Galaxies of this type appear to have a bar of stars slicing through the bulge of stars at their center. The SB classification is further sub-divided by the appearance of a galaxy's pinwheeling spiral arms; SBa types have more tightly wound arms, whereas SBc types have looser ones. SBb types, such as NGC 3455, lie in between. NGC 3455 is part of a pair of galaxies — its partner, NGC 3454, lies out of frame. This cosmic duo belong to a group known as the NGC 3370 group, which is in turn one of the Leo II groups, a large collection of galaxies scattered some 30 million light-years to the right of the Virgo cluster. This image is from Hubble's Advanced Camera for Surveys. Credit: ESA/Hubble & NASA, Acknowledgement: Nick Rose NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Preliminary assessment of channel stability and bed-material transport along Hunter Creek, southwestern Oregon

USGS Publications Warehouse

Jones, Krista L.; Wallick, J. Rose; O'Connor, Jim E.; Keith, Mackenzie K.; Mangano, Joseph F.; Risley, John C.

2011-01-01

This preliminary assessment of (1) bed-material transport in the Hunter Creek basin, (2) historical changes in channel condition, and (3) supplementary data needed to inform permitting decisions regarding instream gravel extraction revealed the following: Along the lower 12.4 km (kilometers) of Hunter Creek from its confluence with the Little South Fork Hunter Creek to its mouth, the river has confined and unconfined segments and is predominately alluvial in its lowermost 11 km. This 12.4-km stretch of river can be divided into two geomorphically distinct study reaches based primarily on valley physiography. In the Upper Study Reach (river kilometer [RKM] 12.4-6), the active channel comprises a mixed bed of bedrock, boulders, and smaller grains. The stream is confined in the upper 1.4 km of the reach by a bedrock canyon and in the lower 2.4 km by its valley. In the Lower Study Reach (RKM 6-0), where the area of gravel bars historically was largest, the stream flows over bed material that is predominately alluvial sediments. The channel alternates between confined and unconfined segments. The primary human activities that likely have affected bed-material transport and the extent and area of gravel bars are (1) historical and ongoing aggregate extraction from gravel bars in the study area and (2) timber harvest and associated road construction throughout the basin. These anthropogenic activities likely have varying effects on sediment transport and deposition throughout the study area and over time. Although assessing the relative effects of these anthropogenic activities on sediment dynamics would be challenging, the Hunter Creek basin may serve as a case study for such an assessment because it is mostly free of other alterations to hydrologic and geomorphic processes such as flow regulation, dredging, and other navigation improvements that are common in many Oregon coastal basins. Several datasets are available that may support a more detailed physical assessment of Hunter Creek. The entire study area has been captured in aerial photographs at least once per decade since the 1940s. This temporally rich photograph dataset would support quantitative analyses of changes in channel planform as well as vegetation cover. Light Detection And Ranging (LiDAR) data collected in 2008 would facilitate hydraulic and sediment-transport modeling and characterization of bar elevations throughout most of the study area. Few studies describing channel morphology and sediment transport exist for the Hunter Creek basin. The most detailed study reported channel incision and bank instability as well as the loss of point bars and pools in the lower 3.9 km of Hunter Creek from slightly downstream of its confluence with Yorke Creek to its mouth (EA Engineering, Sci-ence, and Technology, 1998). Repeat channel cross-sections collected from 1994 to 2010 at four bridges indicate that Hunter Creek is dynamic and subject to channel shifting, aggradation, and incision. Despite this dynamism, the channel at three bridge crossings showed little net change in thalweg elevation during this period. However, the channel thalweg aggraded 0.55 m from 2004 to 2008 near the bridge at RKM 3.5. Systematic delineation of gravel bars from aerial photographs collected in 1940, 1965, 2005, and 2009 indicates a 52-percent reduction in the area of bed-material sediment throughout the study area from 1940 to 2009. Net bar loss was greatest in the Lower Study Reach from RKM 1-4 and mainly is associ-ated with the encroachment of vegetation onto upper-bar surfaces lacking apparent vegetation in 1940. Bar-surface material was approximately equal in size to bar-subsurface material at Conn Creek Bar, whereas it was distinctly coarser than the subsurface material at Menasha Bar. Armoring ratios, which indicate the coarseness of the bar surface relative to the bar subsurface, were calculated as 0.97 for Conn Creek Bar and 1.5 for Menasha Bar. These ratios tentatively show that

Experimental Study of W Z Intermediate Bosons Associated Production with the CDF Experiment at the Tevatron Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pozzobon, Nicola; /Pisa U.

Studying WZ associated production at the Fermilab Tevatron Collider is of great importance for two main reasons. On the one hand, this process would be sensitive to anomalies in the triple gauge couplings such that any deviation from the value predicted by the Standard Model would be indicative of new physics. In addition, by choosing to focus on the final state where the Z boson decays to b{bar b} pairs, the event topology would be the same as expected for associated production of a W and a Standard Model light Higgs boson (m{sub H} {approx}< 135 GeV) which decays intomore » b{bar b} pairs most of times. The process WH {yields} W b{bar b} has an expected {sigma} {center_dot} B about five times lower than WZ {yields} Wb{bar b} for m{sub H} {approx_equal} 120 GeV. Therefore, observing this process would be a benchmark for an even more difficult search aiming at discovering the light Higgs in the WH {yields} Wb{bar b} process. After so many years of Tevatron operation only a weak WZ signal was recently observed in the full leptonic decay channel, which suffers from much less competition from background. Searching for the Z in the b{bar b} decay channel in this process is clearly a very challenging endeavour. In the work described in this thesis, WZ production is searched for in a final state where the W decays leptonically to an electron-neutrino pair or a muon-neutrino pair, with associated production of a jet pair consistent with Z decays. A set of candidate events is obtained by applying appropriate cuts to the parameters of events collected by wide acceptance leptonic triggers. To improve the signal fraction of the selected events, an algorithm was used to tag b-flavored jets by means of their content of long lived b-hadrons and corrections were developed to the jet algorithm to improve the b-jet energy resolution for a better reconstruction of the Z mass. In order to sense the presence of a signal one needs to estimate the amount of background. The relative content of heavy flavor jets in the dominant W+multijet background is assumed as predicted by theory. This technique was originally developed in CDF to measure the t{bar t} production cross section in the final state with W + 3 or more jets. This thesis was conceived as the first attempt within CDF to apply a customized version of it to look for evidence of diboson production in the final state with aW and two jets. Extracting the signal in this channel is very hard since with such a small number of jets the background is two orders of magnitude greater than the signal. Moreover, since the signal to background ratio is very small, the expected sensitivity depends critically on the theoretical uncertainties on the amount of background. While work is in progress to understand this background more reliably, this analysis provides an estimate of the achievable upper limit on the WZ production cross section.« less

An investigation of noncompliant toilet room designs for assisted toileting.

PubMed

Sanford, Jon; Bosch, Sheila J

2013-01-01

By comparing an Americans with Disabilities Act Accessibility Guidelines (ADAAG) compliant design with alternative designs, this pilot study resulted in recommendations for designing patient bathrooms to facilitate assisted toileting. The ADA Accessibility Guidelines were developed primarily to address the needs of disabled populations, such as returning Vietnam veterans, with sufficient upper body strength to transfer independently directly from a wheelchair to the toilet. However, the majority of older persons with disabilities (90%) stand to transfer to the toilet, rather than laterally moving from the wheelchair to the toilet. The research used a repeated measures research design to evaluate caregiver responses during assisted toileting for various toilet configurations. The study included 20 patients who were transferred onto and off of a toilet for each of four different configurations by one or two caregivers. Toileting trials were videotaped and analyzed by an occupational therapist. Additionally, caregivers completed five-question, self-report surveys after each toileting trial. Survey data indicate that staff members prefer the largest of the tested configurations, where the centerline of the toilet is 30 inches from the sidewall, rather than the 18 inches required by the ADAAG, and where there are two fold-down grab bars provided. Caregivers perceived the grab bar locations as better for helping them safely transfer subjects in a modified (non-ADAAG) configuration, and also that the grab bar style in a modified configuration (non-ADAAG) improved safety when transferring subjects. Although caregivers were observed to safely transfer residents to and from the toilet for all configurations tested, regulations regarding accessibility of patient bathrooms should acknowledge the perceived benefits of increasing the distance from the sidewall to the centerline of the toilet to as much as 30 inches and allowing two fold-down grab bars instead of the required sidewall and back-wall grab bars. ADA, toilet room design, healthcare design, evidence-based design, human factors, safety, staffPreferred Citation: Sanford, J., & Bosch, S. (2013). An investigation of noncompliant toilet room designs for assisted toileting. Health Environments Research & Design Journal 6(2), pp 43-57.

Soliton-induced relativistic-scattering and amplification.

PubMed

Rubino, E; Lotti, A; Belgiorno, F; Cacciatori, S L; Couairon, A; Leonhardt, U; Faccio, D

2012-01-01

Solitons are of fundamental importance in photonics due to applications in optical data transmission and also as a tool for investigating novel phenomena ranging from light generation at new frequencies and wave-trapping to rogue waves. Solitons are also moving scatterers: they generate refractive index perturbations moving at the speed of light. Here we found that such perturbations scatter light in an unusual way: they amplify light by the mixing of positive and negative frequencies, as we describe using a first Born approximation and numerical simulations. The simplest scenario in which these effects may be observed is within the initial stages of optical soliton propagation: a steep shock front develops that may efficiently scatter a second, weaker probe pulse into relatively intense positive and negative frequency modes with amplification at the expense of the soliton. Our results show a novel all-optical amplification scheme that relies on soliton induced scattering.

Flies and humans share a motion estimation strategy that exploits natural scene statistics

PubMed Central

Clark, Damon A.; Fitzgerald, James E.; Ales, Justin M.; Gohl, Daryl M.; Silies, Marion A.; Norcia, Anthony M.; Clandinin, Thomas R.

2014-01-01

Sighted animals extract motion information from visual scenes by processing spatiotemporal patterns of light falling on the retina. The dominant models for motion estimation exploit intensity correlations only between pairs of points in space and time. Moving natural scenes, however, contain more complex correlations. Here we show that fly and human visual systems encode the combined direction and contrast polarity of moving edges using triple correlations that enhance motion estimation in natural environments. Both species extract triple correlations with neural substrates tuned for light or dark edges, and sensitivity to specific triple correlations is retained even as light and dark edge motion signals are combined. Thus, both species separately process light and dark image contrasts to capture motion signatures that can improve estimation accuracy. This striking convergence argues that statistical structures in natural scenes have profoundly affected visual processing, driving a common computational strategy over 500 million years of evolution. PMID:24390225

Large Fizeau's light-dragging effect in a moving electromagnetically induced transparent medium.

PubMed

Kuan, Pei-Chen; Huang, Chang; Chan, Wei Sheng; Kosen, Sandoko; Lan, Shau-Yu

2016-10-03

As one of the most influential experiments on the development of modern macroscopic theory from Newtonian mechanics to Einstein's special theory of relativity, the phenomenon of light dragging in a moving medium has been discussed and observed extensively in different types of systems. To have a significant dragging effect, the long duration of light travelling in the medium is preferred. Here we demonstrate a light-dragging experiment in an electromagnetically induced transparent cold atomic ensemble and enhance the dragging effect by at least three orders of magnitude compared with the previous experiments. With a large enhancement of the dragging effect, we realize an atom-based velocimeter that has a sensitivity two orders of magnitude higher than the velocity width of the atomic medium used. Such a demonstration could pave the way for motional sensing using the collective state of atoms in a room temperature vapour cell or solid state material.

Polarization Perception Device

NASA Technical Reports Server (NTRS)

Whitehead, Victor S. (Inventor); Coulson, Kinsell L. (Inventor)

1997-01-01

A polarization perception device comprises a base and a polarizing filter having opposite broad sides and a centerline perpendicular thereto. The filter is mounted on the base for relative rotation and with a major portion of the area of the filter substantially unobstructed on either side. A motor on the base automatically moves the filter angularly about its centerline at a speed slow enough to permit changes in light transmission by virtue of such movement to be perceived as light-dark pulses by a human observer, but fast enough so that the light phase of each such pulse occurs prior to fading of the light phase image of the preceding pulse from the observer's retina. In addition to an observer viewing a scene in real time through the filter while it is so angularly moved, or instead of such observation, the scene can be photographed, filmed or taped by a camera whose lens is positioned behind the filter.

Polarization perception device

NASA Technical Reports Server (NTRS)

Whitehead, Victor S. (Inventor); Coulson, Kinsel L. (Inventor)

1992-01-01

A polarization perception device comprises a base and a polarizing filter having opposite broad sides and a centerline perpendicular thereto. The filter is mounted on the base for relative rotation and with a major portion of the area of the filter substantially unobstructed on either side. A motor on the base automatically moves the filter angularly about its centerline at a speed slow enough to permit changes in light transmission by virtue of such movement to be perceived as light-dark pulses by a human observer, but fast enough so that the light phase of each such pulse occurs prior to fading of the light phase image of the preceding pulse from the observer's retina. In addition to an observer viewing a scene in real time through the filter while it is so angularly moved, or instead of such observation, the scene can be photographed, filmed or taped by a camera whose lens is positioned behind the filter.

Physical conditions at the base of a fast moving antarctic ice stream.

PubMed

Engelhardt, H; Humphrey, N; Kamb, B; Fahnestock, M

1990-04-06

Boreholes drilled to the bottom of ice stream B in the West Antarctic Ice Sheet reveal that the base of the ice stream is at the melting point and the basal water pressure is within about 1.6 bars of the ice overburden pressure. These conditions allow the rapid ice streaming motion to occur by basal sliding or by shear deformation of unconsolidated sediments that underlie the ice in a layer at least 2 meters thick. The mechanics of ice streaming plays a role in the response of the ice sheet to climatic change.

Decentralized control

NASA Technical Reports Server (NTRS)

Steffen, Chris

1990-01-01

An overview of the time-delay problem and the reliability problem which arise in trying to perform robotic construction operations at a remote space location are presented. The effects of the time-delay upon the control system design will be itemized. A high level overview of a decentralized method of control which is expected to perform better than the centralized approach in solving the time-delay problem is given. The lower level, decentralized, autonomous, Troter Move-Bar algorithm is also presented (Troters are coordinated independent robots). The solution of the reliability problem is connected to adding redundancy to the system. One method of adding redundancy is given.

Evaluation of a passive optical based end of service life indicator (ESLI) for organic vapor respirator cartridges

PubMed Central

Checky, Melissa; Frankel, Kevin; Goddard, Denise; Johnson, Erik; Thomas, J. Christopher; Zelinsky, Maria; Javner, Cassidy

2016-01-01

ABSTRACT A passive visual end of service life indicator (ESLI) for certain organic vapors has been attached to the inside wall of an organic vapor respirator cartridge. The opposite side of the ESLI touches activated carbon inside the cartridge. During use, organic vapors moving through the cartridge adsorb into both the carbon and the ESLI. The cartridge body is clear so that when vapor concentrations meet a certain threshold, the user may observe the progressive development of an indicator bar down the side of the ESLI. The cartridge is deemed ready to change when any part of the indicator bar touches a marked end line. The performance of the ESLI was observed when the cartridge was tested against a variety of organic vapors, exposure concentrations above the minimum indication level, humidities, temperatures, flow rates, and mixtures. In all cases, the ESLI indicated end of service life with more than 10% cartridge service life remaining (which is a NIOSH test criteria). The results were also compared to mathematical predictions of cartridge service life. PMID:26418577

Formation of vortex line around the glass transition in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nojima, T.; Kakinuma, A.; Kuwasawa, Y.

1996-12-01

Two components of current-induced electric fields in ab plane, E{sub x} and E{sub y}, have been measured simultaneously on YBCO(123) films around the glass transition temperature T{sub g} in magnetic fields H with components (H{sub 0}, H{sub 0}, 0.1H{sub 0}), where x and y axes are parallel to the direction of the current density and c axis, respectively. In this condition, a finite transverse field E{sub y} almost equal to E{sub x} can be observed if the vortex lines form and move along the Lorentz force. In each H, the ratio {vert_bar}E{sub y}/E{sub x}{vert_bar} at a low current limit, whichmore » is zero far above T{sub g}, increases in the critical region and transfers to unity below T{sub g}. The authors results indicate that the vortices become lines with long range correlation along H direction at the vortex glass transition without receiving the effect of the intrinsic pinning.« less

Micropole undulator

DOEpatents

Csonka, P.L.; Tatchyn, R.O.

1989-01-24

Micropole undulators for use in the generation of x-rays from moving charged particles and methods for manufacturing such undulators are disclosed. One type of micropole undulator has two jaws containing rows of spaced apart poles arranged so that each pole produces a magnetic field aligned with all other similar fields. An external biasing field extends through the jaws so that an overall undulator field of substantially sinusoidal shape and substantially zero average value extends along the undulator axis. Preferably, the poles are bars formed of a magnetizable, but unmagnetized, material so that, after the jaws are assembled, all of the bars can be magnetized simultaneously in a uniform magnetic field of suitable strength. Another type of micropole undulator incorporates two parallel layers which have been magnetized to provide rows of alternating magnetic fields extending in opposite directions, the layers being positioned between the pole faces of a highly magnetically permeable material with the south poles of one layer opposite the north poles of the other. Poles in the layers are formed by subjecting successive regions of each layer to oppositely directed and suitably varied magnetizing forces. 16 figs.

Micropole undulator

DOEpatents

Csonka, Paul L.; Tatchyn, Roman O.

1989-01-24

Micropole undulators for use in the generation of x-rays from moving charged particles and methods for manufacturing such undulators are disclosed. One type of micropole undulator has two jaws containing rows of spaced apart poles arranged so that each pole produces a magnetic field aligned with all other similar fields. An external biasing field extends through the jaws so that an overall undulator field of substantially sinusoidal shape and substantially zero average value extends along the undulator axis. Preferably, the poles are bars formed of a magnetizable, but unmagnetized, material so that, after the jaws are assembled, all of the bars can be magnetized simultaneously in a uniform magnetic field of suitable strength. Another type of micropole undulator incorporates two parallel layers which have been magnetized to provide rows of alternating magnetic fields extending in opposite directions, the layers being positioned between the pole faces of a highly magnetically permeable material with the south poles of one layer opposite the north poles of the other. Poles in the layers are formed by subjecting successive regions of each layer to oppositely directed and suitably varied magnetizing forces.

Detrending moving average algorithm for multifractals

NASA Astrophysics Data System (ADS)

Gu, Gao-Feng; Zhou, Wei-Xing

2010-07-01

The detrending moving average (DMA) algorithm is a widely used technique to quantify the long-term correlations of nonstationary time series and the long-range correlations of fractal surfaces, which contains a parameter θ determining the position of the detrending window. We develop multifractal detrending moving average (MFDMA) algorithms for the analysis of one-dimensional multifractal measures and higher-dimensional multifractals, which is a generalization of the DMA method. The performance of the one-dimensional and two-dimensional MFDMA methods is investigated using synthetic multifractal measures with analytical solutions for backward (θ=0) , centered (θ=0.5) , and forward (θ=1) detrending windows. We find that the estimated multifractal scaling exponent τ(q) and the singularity spectrum f(α) are in good agreement with the theoretical values. In addition, the backward MFDMA method has the best performance, which provides the most accurate estimates of the scaling exponents with lowest error bars, while the centered MFDMA method has the worse performance. It is found that the backward MFDMA algorithm also outperforms the multifractal detrended fluctuation analysis. The one-dimensional backward MFDMA method is applied to analyzing the time series of Shanghai Stock Exchange Composite Index and its multifractal nature is confirmed.

Notes sur les mouvements recursifs (Notes on Regressive Moves).

ERIC Educational Resources Information Center

Auchlin, Antoine; And Others

1981-01-01

Examines the phenomenon of regressive moves (retro-interpretation) in the light of a hypothesis according to which the formation of complex and hierarchically organized conversation units is subordinated to the linearity of discourse. Analyzes a transactional exchange, describing the interplay of integration, anticipation, and retro-interpretation…

New Forensics Methods Looking More Like CSI: Rapid DNA Analysis, Proteomics, and New Technology Increasingly Impact Forensics Investigations.

PubMed

Mertz, Leslie

2017-01-01

If CSI and those other police procedural TV shows are to be believed, criminals don't have a chance. A finger smudge on a light switch, a flake of skin, or a sweat-stained fiber is all the information an investigator needs to positively identify the perpetrator and put him or her behind bars.

The Secret Lives of Galaxies

NASA Technical Reports Server (NTRS)

2001-01-01

The ground-based image in visible light locates the hub imaged with the Hubble Space Telescope. This barred galaxy feeds material into its hub, igniting star birth. The Hubble NICMOS instrument penetrates beneath the dust to reveal clusters of young stars. Footage shows ground-based, WFPC2, and NICMOS images of NGS 1365. An animation of a large spiral galaxy zooms from the edge to the galactic bulge.

Characterization of the actuator of EMIR configurable slit unit

NASA Astrophysics Data System (ADS)

Mato Martínez, A.; Núñez Cagigal, M.; Barreto Cabrera, M.; Garzón López, F.; Patrón, J.; Teuwen, M.

2016-07-01

EMIR1,2 (Espectrógrafo Multiobjeto Infra-Rojo) is a wide field multi-object spectrograph already installed in the Nasmyth focus of GTC (Gran Telescopio Canarias). It operates in the near-infrared (NIR), in the wavelength range from 0.9 μm to 2.5 μm and it will include several mechanism working in cryogenic conditions. A key component of EMIR is the CSU (Configurable Slit Unit), which is a robotic cryo-mechanism used to generate a multi-slit configuration and a long slit on EMIR focal plane when working in spectroscopic mode. The system has 110 sliding bars which can be configured at cryogenic working temperature to create up to 55 slits with a high position accuracy and repeatability. The movement of the bars is performed by an actuator which allows reaching a relatively high speed for the coarse movement and controllable steps up to 2 microns for the fine positioning. This subsystem has been designed and manufactured by the Dutch company Janssen Precision Engineering (JPE) and the Spanish company NTE-SENER. Afterwards, it was thoroughly verified at the IAC (Instituto de Astrofísica de Canarias) facilities. In this paper, the CSU will be briefly described. One of the more important parts of the CSU is the actuators, which move the bars by means of a stick-slip effect. A set of tests designed for characterizing and improving the robustness and performance of the actuators will be presented. Finally, an overview of the current CSU performance will be presented.

TRACING THE HERCULES STREAM AROUND THE GALAXY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bovy, Jo, E-mail: jb2777@nyu.ed

2010-12-20

It has been proposed that the Hercules stream, a group of co-moving stars in the solar neighborhood offset from the bulk of the velocity distribution, is the result of resonant interactions between stars in the outer disk and the Galactic bar. So far it has only been seen in the immediate solar neighborhood, but the resonance model makes a prediction over a large fraction of the Galactic disk. I predict the distribution of stellar velocities and the changing Hercules feature in this distribution as a function of location in the Galactic disk in a simple model for the Galaxy andmore » the bar that produces the observed Hercules stream. The Hercules feature is expected to be strong enough to be unambiguously detected in the distribution of line-of-sight velocities in selected directions. I identify quantitatively the most promising lines of sight for detection in line-of-sight velocities using the Kullback-Leibler divergence between the predictions of the resonance model and an axisymmetric model; these directions are at 250{sup 0} {approx}< l {approx}< 290{sup 0}. The predictions presented here are only weakly affected by distance uncertainties, assumptions about the distribution function in the stellar disk, and the details of the Galactic potential including the effect of spiral structure. Gaia and future spectroscopic surveys of the Galactic disk such as APOGEE and HERMES will be able to robustly test the origin of the Hercules stream and constrain the properties of the Galactic bar.« less

Focusing light inside dynamic scattering media with millisecond digital optical phase conjugation

PubMed Central

Liu, Yan; Ma, Cheng; Shen, Yuecheng; Shi, Junhui; Wang, Lihong V.

2017-01-01

Wavefront shaping based on digital optical phase conjugation (DOPC) focuses light through or inside scattering media, but the low speed of DOPC prevents it from being applied to thick, living biological tissue. Although a fast DOPC approach was recently developed, the reported single-shot wavefront measurement method does not work when the goal is to focus light inside, instead of through, highly scattering media. Here, using a ferroelectric liquid crystal based spatial light modulator, we develop a simpler but faster DOPC system that focuses light not only through, but also inside scattering media. By controlling 2.6 × 105 optical degrees of freedom, our system focused light through 3 mm thick moving chicken tissue, with a system latency of 3.0 ms. Using ultrasound-guided DOPC, along with a binary wavefront measurement method, our system focused light inside a scattering medium comprising moving tissue with a latency of 6.0 ms, which is one to two orders of magnitude shorter than those of previous digital wavefront shaping systems. Since the demonstrated speed approaches tissue decorrelation rates, this work is an important step toward in vivo deep-tissue non-invasive optical imaging, manipulation, and therapy. PMID:28815194

VizieR Online Data Catalog: BVI photometry of LMC bar variables (Di Fabrizio+, 2005)

NASA Astrophysics Data System (ADS)

di Fabrizio, L.; Clementini, G.; Maio, M.; Bragaglia, A.; Carretta, E.; Gratton, R.; Montegriffo, P.; Zoccali, M.

2005-01-01

We present the Johnson-Cousins B,V and I time series data obtained for 162 variable stars (135 RR Lyrae, 4 candidate Anomalous Cepheids, 11 Classical Cepheids, 11 eclipsing binaries and 1 delta Scuti star) in two 13x13 square arcmin areas close to the bar of the Large Magellanic Cloud. The photometric observations presented in this paper were carried out at the 1.54m Danish telescope located in La Silla, Chile, on the nights 4-7 January 1999, UT, and 23-24 January 2001, UT, respectively. In the paper we give coordinates, finding charts, periods, epochs, amplitudes, and mean quantities (intensity- and magnitude-averaged luminosities) of the variables with full coverage of the light variations, along with a discussion of the pulsation properties of the RR Lyrae stars in the sample. (8 data files).

Experimental Equipment Validation for Methane (CH4) and Carbon Dioxide (CO2) Hydrates

NASA Astrophysics Data System (ADS)

Saad Khan, Muhammad; Yaqub, Sana; Manner, Naathiya; Ani Karthwathi, Nur; Qasim, Ali; Mellon, Nurhayati Binti; Lal, Bhajan

2018-04-01

Clathrate hydrates are eminent structures regard as a threat to the gas and oil industry in light of their irritating propensity to subsea pipelines. For natural gas transmission and processing, the formation of gas hydrate is one of the main flow assurance delinquent has led researchers toward conducting fresh and meticulous studies on various aspects of gas hydrates. This paper highlighted the thermodynamic analysis on pure CH4 and CO2 gas hydrates on the custom fabricated equipment (Sapphire cell hydrate reactor) for experimental validation. CO2 gas hydrate formed at lower pressure (41 bar) as compared to CH4 gas hydrate (70 bar) while comparison of thermodynamic properties between CH4 and CO2 also presented in this study. This preliminary study could provide pathways for the quest of potent hydrate inhibitors.

Optimizing the Construction of the A1 Collaboration Neutron Detector

NASA Astrophysics Data System (ADS)

Chinn, Edward; A1 Collaboration

2016-09-01

We report on the design and construction of a frame designed to optimize both the time efficiency and construction quality of the large scintillator elements These elements will be assembled to form a neutron detector for use by the A1 Collaboration at the Institute for Nuclear Physics in Mainz, Germany. The design had to provide adequate support for the 20 kg scintillator bars while gluing light guides and photomultiplier tubes to both sides of the bars using optical cement. The optical cement requires approximately 24 hours to dry and 100 bars have to be glued with this apparatus. To address each of these issues, several different prototypes were designed and reviewed. The selected apparatus minimized size to meet space constraints, with reduced material cost and provided the most time-efficient way to build the neutron detector. Once the schematic design was selected, we produced technical drawings in AutoDesk Inventor. Assembled the structure and completed gluing of the first batch of scintillators, in order to verify the performance. This apparatus was successful at producing high quality scintillators which were evaluated using cosmic rays. National Science Foundation Grant No. IIA-1358175.

The Origin of Gravitation

NASA Astrophysics Data System (ADS)

Zheng, Sheng Ming

2012-10-01

In the natural world, people have discovered four kinds of forces: electromagnetic force, gravitation, weak force, and strong force. Although the gravitation has been discovered more than three hundred years, its mechanism of origin is unclear until today. While investigating the origin of gravitation, I do some experiments discover the moving photons produce gravitation. This discovery shows the origin of gravitation. Meanwhile I do some experiments discover the light interference fringes are produced by the gravitation: my discovery demonstrate light is a particle, but is not a wave-particle duality. Furthermore, applications of this discovery to other moving particles show a similar effect. In a word: the micro particle moving produce gravitation and electromagnetic force. Then I do quantity experiment get a general formula: Reveal the essence of gravitational mass and the essence of electric charge; reveal the origin of gravitation and the essence of matter wave. Along this way, I unify the gravitation and electromagnetic force. Namely I find a natural law that from atomic world to star world play in moving track. See website: https://www.lap-publishing.com/catalog/details/store/gb/book/978-3-8473-2658-8/mechanism-of-interaction-in-moving-matter

Image Reconstruction from Data Collected with an Imaging Interferometer

NASA Astrophysics Data System (ADS)

DeSantis, Z. J.; Thurman, S. T.; Hix, T. T.; Ogden, C. E.

The intensity distribution of an incoherent source and the spatial coherence function at some distance away are related by a Fourier transform, via the Van Cittert-Zernike theorem. Imaging interferometers measure the spatial coherence of light propagated from the incoherently illuminated object by combining light from spatially separated points to measure interference fringes. The contrast and phase of the fringe are the amplitude and phase of a Fourier component of the source’s intensity distribution. The Fiber-Coupled Interferometer (FCI) testbed is a visible light, lab-based imaging interferometer designed to test aspects of an envisioned ground-based interferometer for imaging geosynchronous satellites. The front half of the FCI testbed consists of the scene projection optics, which includes an incoherently backlit scene, located at the focus of a 1 m aperture f/100 telescope. The projected light was collected by the back half of the FCI testbed. The collection optics consisted of three 11 mm aperture fiber-coupled telescopes. Light in the fibers was combined pairwise and dispersed onto a sensor to measure the interference fringe as a function of wavelength, which produces a radial spoke of measurements in the Fourier domain. The visibility function was sampled throughout the Fourier domain by recording fringe data at many different scene rotations and collection telescope separations. Our image reconstruction algorithm successfully produced images for the three scenes we tested: asymmetric pair of pinholes, U.S. Air Force resolution bar target, and satellite scene. The bar target reconstruction shows detail and resolution near the predicted resolution limit. This research was developed with funding from the Defense Advanced Research Projects Agency (DARPA). The views, opinions and/or findings expressed are those of the author(s) and should not be interpreted as reflecting the official views or policies of the Department of Defense or the U.S. Government.

CARMA observations of Galactic cold cores: searching for spinning dust emission

NASA Astrophysics Data System (ADS)

Tibbs, C. T.; Paladini, R.; Cleary, K.; Muchovej, S. J. C.; Scaife, A. M. M.; Stevenson, M. A.; Laureijs, R. J.; Ysard, N.; Grainge, K. J. B.; Perrott, Y. C.; Rumsey, C.; Villadsen, J.

2015-11-01

We present the first search for spinning dust emission from a sample of 34 Galactic cold cores, performed using the CARMA interferometer. For each of our cores, we use photometric data from the Herschel Space Observatory to constrain bar{N}H, bar{T}d, bar{n}H, and bar{G}0. By computing the mass of the cores and comparing it to the Bonnor-Ebert mass, we determined that 29 of the 34 cores are gravitationally unstable and undergoing collapse. In fact, we found that six cores are associated with at least one young stellar object, suggestive of their protostellar nature. By investigating the physical conditions within each core, we can shed light on the cm emission revealed (or not) by our CARMA observations. Indeed, we find that only three of our cores have any significant detectable cm emission. Using a spinning dust model, we predict the expected level of spinning dust emission in each core and find that for all 34 cores, the predicted level of emission is larger than the observed cm emission constrained by the CARMA observations. Moreover, even in the cores for which we do detect cm emission, we cannot, at this stage, discriminate between free-free emission from young stellar objects and spinning dust emission. We emphasize that although the CARMA observations described in this analysis place important constraints on the presence of spinning dust in cold, dense environments, the source sample targeted by these observations is not statistically representative of the entire population of Galactic cores.

A Comparative Morphological Study of the Jugal and Quadratojugal in Early Birds and Their Dinosaurian Relatives.

PubMed

Wang, Min; Hu, Han

2017-01-01

The zygoma (called jugal bar) in modern birds accounts for a large portion of the ventral margin of the cranium. As a delicate and rod-like element, the jugal bar is functionally integrated into the avian cranial kinesis, a unique property that allows the beak to be elevated or depressed with respect to the braincase and thus distinguishes birds from all other modern vertebrates. Developmental studies show that the jugal bar of modern birds is formed by the fusion of the jugal and quadratojugal that are ossified from separated centers. However, those two bones are unfused and exhibit complicated morphological variations in basal birds and their dinosaurian relatives. Moreover, the jugal and quadratojugal form rigid articulations with the postorbital and squamosal, respectively, consequently hindering the movement of the upper jaw in most non-avian dinosaurs and some basal birds. A comparative study of the jugal and quadratojugal morphology of basal birds and their close relatives such as dromaeosaurids and oviraptorids elucidates how modern birds has achieved its derived jugal bar morphology, and sheds light on the evolution of the postorbital configuration of birds. We propose that numerous morphological modifications of those two elements (morphology changes and reduced articulation with other elements) took place in early bird history, and some of them pertinent to the refinement of the cranial kinesis. Anat Rec, 300:62-75, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Asymptotic analysis of quasilinear parabolic-hyperbolic equations describing the large longitudinal motion of a light viscoelastic bar with a heavy attachment

NASA Astrophysics Data System (ADS)

Yip, Shui Cheung

We study the longitudinal motion of a nonlinearly viscoelastic bar with one end fixed and the other end attached to a heavy tip mass. This problem is a precise continuum mechanical analog of the basic discrete mechanical problem of the motion of a mass point on a (massless) spring. This motion is governed by an initial-boundary-value problem for a class of third-order quasilinear parabolic-hyperbolic partial differential equations subject to a nonstandard boundary condition, which is the equation of motion of the tip mass. The ratio of the mass of the bar to that of the tip mass is taken to be a small parameter varepsilon. We prove that this problem has a unique regular solution that admits a valid asymptotic expansion, including an initial-layer expansion, in powers of varepsilon for varepsilon near 0. The fundamental constitutive hypothesis that the tension be a uniformly monotone function of the strain rate plays a critical role in a delicate proof that each term of the initial layer expansion decays exponentially in time. These results depend on new decay estimates for the solution of quasilinear parabolic equations. The constitutive hypothesis that the viscosity become large where the bar nears total compression leads to important uniform bounds for the strain and the strain rate. Higher-order energy estimates support the proof by the Schauder Fixed-Point Theorem of the existence of solutions having a level of regularity appropriate for the asymptotics.

Fine structure of the pecten oculi of the barred owl (Strix varia).

PubMed

Smith, B J; Smith, S A; Braekevelt, C R

1996-01-01

The pecten oculi of the barred owl (Strix varia) has been examined by light and transmission electron microscopy. The pecten in this species is of the pleated type and is small in comparison to the size of the ocular globe. The pecten consists of 8-10 accordion-like folds that are linked apically by a pigmented tissue bridge. Each fold contains numerous capillaries, larger supply and drainage vessels, and abundant pleomorphic melanocytes. Most of these capillaries are extremely specialized vessels that possess plentiful microfolds on both the luminal and abluminal surfaces. Some capillaries however display only a few microfolds. The endothelial cell bodies are extremely attenuated, with most organelles located near the nucleus. All capillaries are surrounded by a very thick fibrillar basal lamina, which is thought to provide structural support to these small vessels. Pericytes are commonly found within these thickened basal laminae. Numerous melanocytes are also present, with processes that form an incomplete sheath around the capillaries. These processes are also presumed to provide structural support for the capillaries. As in other avian species, the morphology of the barred owl pecten is indicative of extensive involvement in substance transport. When compared to the pecten of more visually-oriented species, this pecten is smaller, has fewer folds, and displays a reduced number of microfolds within the capillaries. In these and other features, the barred owl pecten is similar to the pecten of the great horned owl (Bubo virginianus).

Light-Front Holography, Light-Front Wavefunctions, and Novel QCD Phenomena

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.

2012-02-16

Light-Front Holography is one of the most remarkable features of the AdS/CFT correspondence. In spite of its present limitations it provides important physical insights into the nonperturbative regime of QCD and its transition to the perturbative domain. This novel framework allows hadronic amplitudes in a higher dimensional anti-de Sitter (AdS) space to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The model leads to an effective confining light-front QCD Hamiltonian and a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z inmore » AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound-state wavefunctions, and thus the fall-off as a function of the invariant mass of the constituents. The soft-wall holographic model modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics - a semi-classical frame-independent first approximation to the spectra and light-front wavefunctions of meson and baryons. The model predicts a Regge spectrum of linear trajectories with the same slope in the leading orbital angular momentum L of hadrons and the radial quantum number n. The hadron eigensolutions projected on the free Fock basis provides the complete set of valence and non-valence light-front Fock state wavefunctions {Psi}{sub n/H} (x{sub i}, k{sub {perpendicular}i}, {lambda}{sub i}) which describe the hadron's momentum and spin distributions needed to compute the direct measures of hadron structure at the quark and gluon level, such as elastic and transition form factors, distribution amplitudes, structure functions, generalized parton distributions and transverse momentum distributions. The effective confining potential also creates quark-antiquark pairs from the amplitude q {yields} q{bar q}q. Thus in holographic QCD higher Fock states can have any number of extra q{bar q} pairs. We discuss the relevance of higher Fock-states for describing the detailed structure of space and time-like form factors. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method in order to systematically include the QCD interaction terms. A new perspective on quark and gluon condensates is also obtained.« less

Electromagnetic multipole moments of the P_c^+(4380) pentaquark in light-cone QCD

NASA Astrophysics Data System (ADS)

Özdem, U.; Azizi, K.

2018-05-01

We calculate the electromagnetic multipole moments of the P_c^+(4380) pentaquark by modeling it as the diquark-diquark-antiquark and {\\bar{D}}^*Σ _c molecular state with quantum numbers J^P = 3/2^-. In particular, the magnetic dipole, electric quadrupole and magnetic octupole moments of this particle are extracted in the framework of light-cone QCD sum rule. The values of the electromagnetic multipole moments obtained via two pictures differ substantially from each other, which can be used to pin down the underlying structure of P_c^+(4380). The comparison of any future experimental data on the electromagnetic multipole moments of the P_c^+(4380) pentaquark with the results of the present work can shed light on the nature and inner quark organization of this state.

Full spectrum optical safeguard

DOEpatents

Ackerman, Mark R.

2008-12-02

An optical safeguard device with two linear variable Fabry-Perot filters aligned relative to a light source with at least one of the filters having a nonlinear dielectric constant material such that, when a light source produces a sufficiently high intensity light, the light alters the characteristics of the nonlinear dielectric constant material to reduce the intensity of light impacting a connected optical sensor. The device can be incorporated into an imaging system on a moving platform, such as an aircraft or satellite.

Nespolia moving the Neurospat Hardware in the Columbus Module during Expedition 26

NASA Image and Video Library

2010-12-20

ISS026-E-012919 (20 Dec. 2010) --- European Space Agency astronaut Paolo Nespoli, Expedition 26 flight engineer, moves the Neurospat hardware (including light shield and frame) used for the Bodies in the Space Environment (BISE) experiment, in the Columbus Module aboard the International Space Station.

The orbital motion of the quintuplet cluster—a common origin for the arches and quintuplet clusters?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stolte, A.; Hußmann, B.; Habibi, M.

2014-07-10

We investigate the orbital motion of the Quintuplet cluster near the Galactic center with the aim of constraining formation scenarios of young, massive star clusters in nuclear environments. Three epochs of adaptive optics high-angular resolution imaging with the Keck/NIRC2 and Very Large Telescope/NAOS-CONICA systems were obtained over a time baseline of 5.8 yr, delivering an astrometric accuracy of 0.5-1 mas yr{sup –1}. Proper motions were derived in the cluster reference frame and were used to distinguish cluster members from the majority of the dense field star population toward the inner bulge. Fitting the cluster and field proper motion distributions withmore » two-dimensional (2D) Gaussian models, we derive the orbital motion of the cluster for the first time. The Quintuplet is moving with a 2D velocity of 132 ± 15 km s{sup –1} with respect to the field along the Galactic plane, which yields a three-dimensional orbital velocity of 167 ± 15 km s{sup –1} when combined with the previously known radial velocity. From a sample of 119 stars measured in three epochs, we derive an upper limit to the velocity dispersion of σ{sub 1D} < 10 km s{sup –1} in the core of the Quintuplet cluster. Knowledge of the three velocity components of the Quintuplet allows us to model the cluster orbit in the potential of the inner Galaxy. Under the assumption that the Quintuplet is located in the central 200 pc at the present time, these simulations exclude the possibility that the cluster is moving on a circular orbit. Comparing the Quintuplet's orbit with our earlier measurements of the Arches' orbit, we discuss the possibility that both clusters originated in the same area of the central molecular zone (CMZ). According to the model of Binney et al., two families of stable cloud orbits are located along the major and minor axes of the Galactic bar, named x1 and x2 orbits, respectively. The formation locus of these clusters is consistent with the outermost x2 orbit and might hint at cloud collisions at the transition region between the x1 and x2 orbital families located at the tip of the minor axis of the Galactic bar. The formation of young, massive star clusters in circumnuclear rings is discussed in the framework of the channeling in of dense gas by the bar potential. We conclude that the existence of a large-scale bar plays a major role in supporting ongoing star and cluster formation, not only in nearby spiral galaxies with circumnuclear rings, but also in the Milky Way's CMZ.« less

Seven Experiments to Test the Local Lorentz Invariance of c

NASA Technical Reports Server (NTRS)

Gezari, Daniel Y.

2005-01-01

The speed of light has never been measured directly with a moving detector to test the fundamental assertion of special relativity that c is invariant to motion of the observer. Seven simple experiments are proposed, four of which could test the invariance of c to motion of the detector. Three other observations of moving sources could test Einstein s second postulate and the relativity of stellar aberration. There are lingering concerns that the speed of light may depend on the motion of the observer, after all. This issue can now be resolved by experiment.

Distributed proximity sensor system having embedded light emitters and detectors

NASA Technical Reports Server (NTRS)

Lee, Sukhan (Inventor)

1990-01-01

A distributed proximity sensor system is provided with multiple photosensitive devices and light emitters embedded on the surface of a robot hand or other moving member in a geometric pattern. By distributing sensors and emitters capable of detecting distances and angles to points on the surface of an object from known points in the geometric pattern, information is obtained for achieving noncontacting shape and distance perception, i.e., for automatic determination of the object's shape, direction and distance, as well as the orientation of the object relative to the robot hand or other moving member.

Recent Measurement of Flavor Asymmetry of Antiquarks in the Proton by Drell–Yan Experiment SeaQuest at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagai, Kei

A measurement of the flavor asymmetry of the antiquarks (more » $$\\bar{d}$$ and $$\\bar{u}$$) in the proton is described in this thesis. The proton consists of three valence quarks, sea quarks, and gluons. Antiquarks in the proton are sea quarks. They are generated from the gluon splitting: g → q + $$\\bar{q}$$. According to QCD (Quantum Chromodynamics), the gluon splitting is independent of quark flavor. It suggests that the amounts of $$\\bar{d}$$ and $$\\bar{u}$$ should be the same in the proton. However, the NMC experiment at CERN found that the amount of $$\\bar{d}$$ is larger than that of $$\\bar{u}$$ in the proton using the deep inelastic scattering in 1991. This result is obtained for $$\\bar{d}$$ and $$\\bar{u}$$ integrated over Bjorken x. Bjorken x is the fraction of the momentum of the parton to that of the proton. The NA51 experiment (x ~ 0.2) at CERN and E866/NuSea experiment (0.015 < x < 0.35) at Fermilab measured the flavor asymmetry of the antiquarks ($$\\bar{d}$$/$$\\bar{u}$$) in the proton as a function of x using Drell–Yan process. The experiments reported that the flavor symmetry is broken over all measured x values. Understanding the flavor asymmetry of the antiquarks in the proton is a challenge of the QCD. The theo- retical investigation from the first principle of QCD such as lattice QCD calculation is important. In addition, the QCD effective models and hadron models such as the meson cloud model can also be tested with the flavor asymmetry of antiquarks. From the experimental side, it is important to measure with higher accuracy and in a wider x range. The SeaQuest (E906) experiment measures $$\\bar{d}$$/$$\\bar{u}$$ at large x (0.15 < x < 0.45) accurately to understand its behavior. The SeaQuest experiment is a Drell–Yan experiment at Fermi National Accelerator Laboratory (Fermilab). In the Drell–Yan process of proton-proton reaction, an antiquark in a proton and a quark in another proton annihilate and create a virtual photon, which then decays into a muon pair (q$$\\bar{q}$$ → γ* → µ +µ -). The SeaQuest experiment uses a 120 GeV proton beam extracted from Fermilab’s Main Injector. The proton beam interacts with hydrogen and deuterium targets. The SeaQuest spectrometer detects the muon pairs from the Drell–Yan process. The $$\\bar{d}$$/$$\\bar{u}$$ ratio at 0.1 < x < 0.58 is extracted from the number of detected Drell–Yan muon pairs. After the detector construction, commissioning run and detector upgrade, the SeaQuest experiment started the physics data acquisition from 2013. We finished so far three periods of physics data acquisition. The fourth period is in progress. The detector construction, detector performance evaluation, data taking and data analysis for the flavor asymmetry of the antiquarks $$\\bar{d}$$/$$\\bar{u}$$ in the proton are my contribution to SeaQuest. The cross section ratio of Drell–Yan process in p- p and p-d reactions is obtained from dimuon yields. In the experiment with high beam intensity, it is important to control the tracking efficiency of charged particles through the magnetic spectrometer. The tracking efficiency depends on the chamber occupancy, and the appropriate method for the correction is important. The chamber occupancy is the number of hits in drift chambers. A new method of the correction for the tracking efficiency is developed based on the occupancy, and applied to the data. This method reflects the real response of the drift chambers. Therefore, the systematic error is well controlled by this method. The flavor asymmetry of antiquarks is obtained at 0.1 < x < 0.58. At 0.1 < x < 0.45, the result is $$\\bar{d}$$/$$\\bar{u}$$ > 1. The result at 0.1 < x < 0.24 agrees with the E866 result. The result at x > 0.24, however, disagrees with the E866 result. The result at 0.45 < x < 0 the statistical errors. u¯ results extracted from experiments are used to investigate the validity of the theoretical models. The present experimental result provides the data points in wide x region. It is useful for understanding the proton structure in the light of QCD and effective hadron models. The present result has a practical application as well. Antiquark distributions are important as inputs to simulations of hadron reactions such as W± production in various experiments. The new knowledge on antiquark distributions helps to improve the precision of the simulations.« less

Outdoor smoking behaviour and support for outdoor smoking restrictions before and after France's national smoking ban.

PubMed

Kennedy, Ryan David; Behm, Ilan; Craig, Lorraine; Thompson, Mary E; Fong, Geoffrey T; Guignard, Romain; Beck, Francois

2012-02-01

On January 1, 2008, the French government implemented a national ban on indoor smoking in hospitality venues. Survey results indicate the indoor ban has been successful at dramatically reducing indoor smoking; however, there are reports of an increased number of outdoor hospitality spaces (patios) where smoking can take place. This study sought to understand if the indoor ban simply moved smoking to the outdoors, and to assess levels of support for smoking restrictions in outdoor hospitality settings after the smoke-free law. Telephone interviews were conducted among 1067 adult smokers before and after the 2008 indoor ban as part of the International Tobacco Control (ITC) France Survey. Among other topics, this survey measures how the smoking ban has influenced smoking behaviour relevant to outdoor sections of hospitality venues. In addition, 414 non-smoking adults and 164 respondents who had quit smoking between waves were also asked about support for outdoor smoking restrictions. Reported smoking outdoors at cafés/pubs/bars increased from 33.6% of smokers at Wave 1 to 75.9% at Wave 2. At restaurants, smoking outdoors increased from 28.9% to 59.0%. There was also an increase in reported non-smoking for both visits to cafés/pubs/bars, and restaurants from 13.4% to 24.7%, and 30.4% to 40.8% respectively. The majority of smokers (74.5%), non-smokers (89.4%) and quitters (74.0%) support a partial or complete ban on smoking in outdoor areas of restaurants. The indoor smoking ban moved smoking to outdoor spaces; however, the ban is also associated with increased non-smoking behaviour. The majority of respondents support outdoor smoking restrictions in patio environments.

Outdoor smoking behaviour and support for outdoor smoking restrictions before and after France's national smoking ban

PubMed Central

Kennedy, Ryan David; Behm, Ilan; Craig, Lorraine; Thompson, Mary E.; Fong, Geoffrey T.; Guignard, Romain; Beck, Francois

2012-01-01

Background: On January 1, 2008, the French government implemented a national ban on indoor smoking in hospitality venues. Survey results indicate the indoor ban has been successful at dramatically reducing indoor smoking; however, there are reports of an increased number of outdoor hospitality spaces (patios) where smoking can take place. This study sought to understand if the indoor ban simply moved smoking to the outdoors, and to assess levels of support for smoking restrictions in outdoor hospitality settings after the smoke-free law. Methods: Telephone interviews were conducted among 1067 adult smokers before and after the 2008 indoor ban as part of the International Tobacco Control (ITC) France Survey. Among other topics, this survey measures how the smoking ban has influenced smoking behaviour relevant to outdoor sections of hospitality venues. In addition, 414 non-smoking adults and 164 respondents who had quit smoking between waves were also asked about support for outdoor smoking restrictions. Results: Reported smoking outdoors at cafés/pubs/bars increased from 33.6% of smokers at Wave 1 to 75.9% at Wave 2. At restaurants, smoking outdoors increased from 28.9% to 59.0%. There was also an increase in reported non-smoking for both visits to cafés/pubs/bars, and restaurants from 13.4% to 24.7%, and 30.4% to 40.8% respectively. The majority of smokers (74.5%), non-smokers (89.4%) and quitters (74.0%) support a partial or complete ban on smoking in outdoor areas of restaurants. Conclusion: The indoor smoking ban moved smoking to outdoor spaces; however, the ban is also associated with increased non-smoking behaviour. The majority of respondents support outdoor smoking restrictions in patio environments. PMID:22294782

Simple quality assurance method of dynamic tumor tracking with the gimbaled linac system using a light field.

PubMed

Miura, Hideharu; Ozawa, Shuichi; Hayata, Masahiro; Tsuda, Shintaro; Yamada, Kiyoshi; Nagata, Yasushi

2016-09-08

We proposed a simple visual method for evaluating the dynamic tumor tracking (DTT) accuracy of a gimbal mechanism using a light field. A single photon beam was set with a field size of 30 × 30 mm2 at a gantry angle of 90°. The center of a cube phantom was set up at the isocenter of a motion table, and 4D modeling was performed based on the tumor and infrared (IR) marker motion. After 4D modeling, the cube phantom was replaced with a sheet of paper, which was placed perpen-dicularly, and a light field was projected on the sheet of paper. The light field was recorded using a web camera in a treatment room that was as dark as possible. Calculated images from each image obtained using the camera were summed to compose a total summation image. Sinusoidal motion sequences were produced by moving the phantom with a fixed amplitude of 20 mm and different breathing periods of 2, 4, 6, and 8 s. The light field was projected on the sheet of paper under three conditions: with the moving phantom and DTT based on the motion of the phantom, with the moving phantom and non-DTT, and with a stationary phantom for comparison. The values of tracking errors using the light field were 1.12 ± 0.72, 0.31 ± 0.19, 0.27 ± 0.12, and 0.15 ± 0.09 mm for breathing periods of 2, 4, 6, and 8s, respectively. The tracking accuracy showed dependence on the breath-ing period. We proposed a simple quality assurance (QA) process for the tracking accuracy of a gimbal mechanism system using a light field and web camera. Our method can assess the tracking accuracy using a light field without irradiation and clearly visualize distributions like film dosimetry. © 2016 The Authors.

VLSI Implementation of Digital Fourier Transforms.

DTIC Science & Technology

1982-11-01

If we use this lemna and the identities (29) and (30) to expand (34). we arrive at ",)(l., , )BR l - ) • • , ,, - - , (36) :.:"s "’" n -( 01)/(L...moving potential wells, that travel along the surface of the silicon crystal. Information is contained as a packet of minority carriers in these moving...drain areas (figure 29). Charge coupled devices on the other hand move minority carriers through lightly doped substrate regions close to the surface. The

Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

NASA Astrophysics Data System (ADS)

Biernaux, J.; Magain, P.; Hauret, C.

2017-08-01

Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system. Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars. Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure the flux within the Einstein radius and to compute secure error bars to all of our results.

Searches for dark photons at e{sup +}e{sup −} colliders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bossi, Fabio

2013-11-07

Searches for new, light, neutral vector particles are being pursued by several different experiments in the world, using e{sup +}e{sup −} collsion data at center-of-mass energies ranging between ∼1 and ∼10 GeV. In this paper I will review the most recent results from KLOE, BESIII, BaBar and Belle and briefly discuss open issues and future perspectives in the field.

Impact of Fiber Optics on System Reliability and Maintainability

DTIC Science & Technology

1988-06-01

200 3-23 Log-normal plot showing the general relationship between emitter lifetime and case temperature . . .. 217 Chapter 4. PHOTODECTORS AND...stereo equipment use infrared signals to transmit the control information. Infrared light is also used in security systems for motion and intrusion...detection. Most modern grocery stores have laser scanners at the checkout line to read the bar code information printed on the packages. Infrared radar

Motion vision is independent of color in Drosophila

PubMed Central

Yamaguchi, Satoko; Wolf, Reinhard; Desplan, Claude; Heisenberg, Martin

2008-01-01

Whether motion vision uses color contrast is a controversial issue that has been investigated in several species, from insects to humans. We used Drosophila to answer this question, monitoring the optomotor response to moving color stimuli in WT and genetic variants. In the fly eye, a motion channel (outer photoreceptors R1–R6) and a color channel (inner photoreceptors R7 and R8) have been distinguished. With moving bars of alternating colors and high color contrast, a brightness ratio of the two colors can be found, at which the optomotor response is largely missing (point of equiluminance). Under these conditions, mutant flies lacking functional rhodopsin in R1–R6 cells do not respond at all. Furthermore, genetically eliminating the function of photoreceptors R7 and R8 neither alters the strength of the optomotor response nor shifts the point of equiluminance. We conclude that the color channel (R7/R8) does not contribute to motion detection as monitored by the optomotor response. PMID:18353989

Motion vision is independent of color in Drosophila.

PubMed

Yamaguchi, Satoko; Wolf, Reinhard; Desplan, Claude; Heisenberg, Martin

2008-03-25

Whether motion vision uses color contrast is a controversial issue that has been investigated in several species, from insects to humans. We used Drosophila to answer this question, monitoring the optomotor response to moving color stimuli in WT and genetic variants. In the fly eye, a motion channel (outer photoreceptors R1-R6) and a color channel (inner photoreceptors R7 and R8) have been distinguished. With moving bars of alternating colors and high color contrast, a brightness ratio of the two colors can be found, at which the optomotor response is largely missing (point of equiluminance). Under these conditions, mutant flies lacking functional rhodopsin in R1-R6 cells do not respond at all. Furthermore, genetically eliminating the function of photoreceptors R7 and R8 neither alters the strength of the optomotor response nor shifts the point of equiluminance. We conclude that the color channel (R7/R8) does not contribute to motion detection as monitored by the optomotor response.

Moving from affirmation to liberation in psychological practice with transgender and gender nonconforming clients.

PubMed

Singh, Anneliese A

2016-11-01

While affirmative approaches with transgender and gender nonconforming (TGNC) clients are gaining momentum within psychological practice (American Counseling Association, 2010; American Psychological Association, 2015), there is a simultaneous and pressing need to move beyond TGNC-affirmative to TGNC-liberatory approaches to more fully address how societal gender binaries influence both psychologist and client. Psychologists may use the lens of liberation psychology (Martín-Baró, 1996) to transform the ways they work with TGNC clients. Using this perspective, psychologists can reflect on their own gender journey and experiences, identify how cisgender privilege influences counseling and psychological practice, and advocate for TGNC people to be better served in the settings in which they work. Psychologists are then able to engage in social change on behalf of, and in collaboration with, TGNC people in ways that simultaneously liberate psychologists from their own gender oppression experiences. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Quick actuating closure

NASA Technical Reports Server (NTRS)

White, III, Dorsey E. (Inventor); Updike, deceased, Benjamin T. (Inventor); Allred, Johnny W. (Inventor)

1989-01-01

A quick actuating closure for a pressure vessel 80 in which a wedge ring 30 with a conical outer surface 31 is moved forward to force shear blocks 40, with conical inner surfaces 41, radially outward to lock an end closure plug 70 within an opening 81 in the pressure vessel 80. A seal ring 60 and a preload ramp 50 sit between the shear blocks 40 and the end closure plug 70 to provide a backup sealing capability. Conical surfaces 44 and 55 of the preload ramp 50 and the shear blocks 40 interact to force the seal ring 60 into shoulders 73 and 85 in the end closure plug 70 and opening 81 to form a tight seal. The end closure plug 70 is unlocked by moving the wedge ring 30 rearward, which causes T-bars 32 of the wedge ring 30 riding within T -slots 42 of the shear blocks 40 to force them radially inward. The end closure plug 70 is then removed, allowing access to the interior of the pressure vessel 80.

Instrument Package Manipulation Through the Generation and Use of an Attenuated-Fluent Gas Fold

NASA Technical Reports Server (NTRS)

Breen, Daniel P.

2012-01-01

This document discusses a technique that provides a means for suspending large, awkward loads, instrument packages, components, and machinery in a stable, controlled, and precise manner. In the baseplate of the test machine, a pattern of grooves and ports is installed that when pressurized generates an attenuated- fluent gas fold providing a low-cost, near-zero-coefficient-of-friction lubrication boundary layer that supports the object evenly, and in a predictable manner. Package movement control requires minimal force. Aids to repeatable travel and positional accuracy can be added via the addition of simple guide bars and stops to the floor or object being moved. This allows easily regulated three-axis motions. Loads of extreme weight and size can be moved and guided by a single person, or by automated means, using minimal force. Upon removal of the attenuated fluent gas fold, the object returns to a stable resting position without impact forces affecting the object.

Reaction CH3 + OH studied over the 294-714 K temperature and 1-100 bar pressure ranges.

PubMed

Sangwan, Manuvesh; Chesnokov, Evgeni N; Krasnoperov, Lev N

2012-08-30

Reaction of methyl radicals with hydroxyl radicals, CH(3) + OH → products (1) was studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 294-714 K temperature and 1-100 bar pressure ranges (bath gas He). Methyl radicals were produced by photolysis of acetone at 193.3 nm. Hydroxyl radicals were generated in reaction of electronically excited oxygen atoms O((1)D), produced in the photolysis of N(2)O at 193.3 nm, with H(2)O. Temporal profiles of CH(3) were recorded via absorption at 216.4 nm using xenon arc lamp and a spectrograph; OH radicals were monitored via transient absorption of light from a dc discharge H(2)O/Ar low pressure resonance lamp at ca. 308 nm. The absolute intensity of the photolysis light inside the reactor was determined by an accurate in situ actinometry based on the ozone formation in the presence of molecular oxygen. The results of this study indicate that the rate constant of reaction 1 is pressure independent within the studied pressure and temperature ranges and has slight negative temperature dependence, k(1) = (1.20 ± 0.20) × 10(-10)(T/300)(-0.49) cm(3) molecule(-1) s(-1).

The analysis of optical-electro collimated light tube measurement system

NASA Astrophysics Data System (ADS)

Li, Zhenhui; Jiang, Tao; Cao, Guohua; Wang, Yanfei

2005-12-01

A new type of collimated light tube (CLT) is mentioned in this paper. The analysis and structure of CLT are described detail. The reticle and discrimination board are replaced by a optical-electro graphics generator, or DLP-Digital Light Processor. DLP gives all kinds of graphics controlled by computer, the lighting surface lies on the focus of the CLT. The rays of light pass through the CLT, and the tested products, the image of aim is received by variant focus objective CCD camera, the image can be processed by computer, then, some basic optical parameters will be obtained, such as optical aberration, image slope, etc. At the same time, motorized translation stage carry the DLP moving to simulate the limited distance. The grating ruler records the displacement of the DLP. The key technique is optical-electro auto-focus, the best imaging quality can be gotten by moving 6-D motorized positioning stage. Some principal questions can be solved in this device, for example, the aim generating, the structure of receiving system and optical matching.

Haptic Tracking Permits Bimanual Independence

ERIC Educational Resources Information Center

Rosenbaum, David A.; Dawson, Amanda A.; Challis, John H.

2006-01-01

This study shows that in a novel task--bimanual haptic tracking--neurologically normal human adults can move their 2 hands independently for extended periods of time with little or no training. Participants lightly touched buttons whose positions were moved either quasi-randomly in the horizontal plane by 1 or 2 human drivers (Experiment 1), in…

Study on the Dose Uncertainties in the Lung during Passive Proton Irradiation with a Proton Beam Range Compensator

NASA Astrophysics Data System (ADS)

Yoo, Seung Hoon; Son, Jae Man; Yoon, Myonggeun; Park, Sung Yong; Shin, Dongho; Min, Byung Jun

2018-06-01

A moving phantom is manufactured for mimicking lung model to study the dose uncertainty from CT number-stopping power conversion and dose calculation in the soft tissue, light lung tissue and bone regions during passive proton irradiation with compensator smearing value. The phantom is scanned with a CT system, and a proton beam irradiation plan is carried out with the use of a treatment planning system (Eclipse). In the case of the moving phantom, a RPM system is used for respiratory gating. The uncertainties in the dose distribution between the measured data and the planned data are investigated by a gamma analysis with 3%-3 mm acceptance criteria. To investigate smearing effect, three smearing values (0.3 cm, 0.7 cm, 1.2 cm) are used to for fixed and moving phantom system. For both fixed and moving phantom, uncertainties in the light lung tissue are severe than those in soft tissue region in which the dose uncertainties are within clinically tolerable ranges. As the smearing value increases, the uncertainty in the proton dose distribution decreases.

Compressional and Shear Wakes in a 2D Dusty Plasma Crystal

NASA Astrophysics Data System (ADS)

Nosenko, V.; Goree, J.; Ma, Z. W.; Dubin, D. H. E.

2001-10-01

A 2D crystalline lattice can vibrate with two kinds of sound waves, compressional and shear (transverse), where the latter has a much slower sound speed. When these waves are excited by a moving supersonic disturbance, the superposition of the waves creates a Mach cone, i.e., a V-shaped wake. In our experiments, the supersonic disturbance was a moving spot of argon laser light, and this laser light applied a force, due to radiation pressure, on the particles. The beam was swept across the lattice in a controlled and repeatable manner. The particles were levitated in an argon rf discharge. By moving the laser spot faster than the shear sound speed c_t, but slower than the compressional sound speed c_l, we excited a shear wave Mach cone. Alternatively, by moving the laser spot faster than c_l, we excited both cones. In addition to Mach cones, we also observed a wake structure that arises from the compressional wave’s dispersion. We compare our results to Dubin’s theory (Phys. Plasmas 2000) and to molecular dynamics (MD) simulations.

Sensory integration of a light touch reference in human standing balance.

PubMed

Assländer, Lorenz; Smith, Craig P; Reynolds, Raymond F

2018-01-01

In upright stance, light touch of a space-stationary touch reference reduces spontaneous sway. Moving the reference evokes sway responses which exhibit non-linear behavior that has been attributed to sensory reweighting. Reweighting refers to a change in the relative contribution of sensory cues signaling body sway in space and light touch cues signaling finger position with respect to the body. Here we test the hypothesis that the sensory fusion process involves a transformation of light touch signals into the same reference frame as other sensory inputs encoding body sway in space, or vice versa. Eight subjects lightly gripped a robotic manipulandum which moved in a circular arc around the ankle joint. A pseudo-randomized motion sequence with broad spectral characteristics was applied at three amplitudes. The stimulus was presented at two different heights and therefore different radial distances, which were matched in terms of angular motion. However, the higher stimulus evoked a significantly larger sway response, indicating that the response was not matched to stimulus angular motion. Instead, the body sway response was strongly related to the horizontal translation of the manipulandum. The results suggest that light touch is integrated as the horizontal distance between body COM and the finger. The data were well explained by a model with one feedback loop minimizing changes in horizontal COM-finger distance. The model further includes a second feedback loop estimating the horizontal finger motion and correcting the first loop when the touch reference is moving. The second loop includes the predicted transformation of sensory signals into the same reference frame and a non-linear threshold element that reproduces the non-linear sway responses, thus providing a mechanism that can explain reweighting.

Sensory integration of a light touch reference in human standing balance

PubMed Central

Smith, Craig P.; Reynolds, Raymond F.

2018-01-01

In upright stance, light touch of a space-stationary touch reference reduces spontaneous sway. Moving the reference evokes sway responses which exhibit non-linear behavior that has been attributed to sensory reweighting. Reweighting refers to a change in the relative contribution of sensory cues signaling body sway in space and light touch cues signaling finger position with respect to the body. Here we test the hypothesis that the sensory fusion process involves a transformation of light touch signals into the same reference frame as other sensory inputs encoding body sway in space, or vice versa. Eight subjects lightly gripped a robotic manipulandum which moved in a circular arc around the ankle joint. A pseudo-randomized motion sequence with broad spectral characteristics was applied at three amplitudes. The stimulus was presented at two different heights and therefore different radial distances, which were matched in terms of angular motion. However, the higher stimulus evoked a significantly larger sway response, indicating that the response was not matched to stimulus angular motion. Instead, the body sway response was strongly related to the horizontal translation of the manipulandum. The results suggest that light touch is integrated as the horizontal distance between body COM and the finger. The data were well explained by a model with one feedback loop minimizing changes in horizontal COM-finger distance. The model further includes a second feedback loop estimating the horizontal finger motion and correcting the first loop when the touch reference is moving. The second loop includes the predicted transformation of sensory signals into the same reference frame and a non-linear threshold element that reproduces the non-linear sway responses, thus providing a mechanism that can explain reweighting. PMID:29874252

Impact of the winter 2013-2014 series of severe Western Europe storms on a double-barred sandy coast: Beach and dune erosion and megacusp embayments

NASA Astrophysics Data System (ADS)

Castelle, Bruno; Marieu, Vincent; Bujan, Stéphane; Splinter, Kristen D.; Robinet, Arhur; Sénéchal, Nadia; Ferreira, Sophie

2015-06-01

The winter of 2013/2014 was characterized by a striking pattern of temporal and spatial extreme storm wave clustering in Western Europe. The 110-km long Gironde coast, SW France, was exposed to the most energetic wave conditions over the last 18 years. The period was outstanding in terms of the available energy to move sediment and cause large-scale erosion with the 2-month average significant wave height (Hs) exceeding 3.6 m, just below the 0.95 quantile, and 4 distinct 10-year return period storms with Hs > 9 m. These storm waves caused unprecedented beach and dune erosion along the Gironde coast, including severely damaged sea defences at the coastal towns. At the end of the winter, dune erosion scarp height was highly variable alongshore and often exceeded 10 m. Megacusp embayments were observed along the Gironde coast with an average alongshore spacing of 1000 m in the south progressively decreasing to 500 m in the north, with an average cross-shore amplitude of 20 m. While beach megacusps were previously observed to systematically couple to the inner bar along the Gironde coast during low- to moderate-energy wave conditions, severe storm-driven megacusp embayments cutting the dune were found to be enforced and coupled to the outer crescentic bar. A detailed inspection of the 1500 m-long bimonthly topographic surveys of Truc Vert beach shows that in early January 2014 the outstanding shore-normal incident storm swell 'Hercules', with Hs and peak wave period Tp peaking at 9.6 m and 22 s, respectively, triggered the formation of a localized megacusp embayment with the erosion scarp height exceeding 6 m in its centre where the dune retreat reached 30 m. The subsequent storms progressively smoothed the megacusp by the end of the winter, mostly through severe erosion of the megacusp horns. Because of the very long period (16 s < Tp < 23 s) storm waves with persistent shore-normal incidence, the well-developed outer crescentic bar observed prior to the winter did not straighten. Instead, the outer-bar three-dimensionality developed further, particularly during 'Hercules'. Our observations indicate that both the antecedent outer sandbar morphology and storm wave characteristics, including period and angle of incidence, govern patterns of beach and dune erosion along open multiple-barred sandy coasts during severe storms.

Sensor modeling and demonstration of a multi-object spectrometer for performance-driven sensing

NASA Astrophysics Data System (ADS)

Kerekes, John P.; Presnar, Michael D.; Fourspring, Kenneth D.; Ninkov, Zoran; Pogorzala, David R.; Raisanen, Alan D.; Rice, Andrew C.; Vasquez, Juan R.; Patel, Jeffrey P.; MacIntyre, Robert T.; Brown, Scott D.

2009-05-01

A novel multi-object spectrometer (MOS) is being explored for use as an adaptive performance-driven sensor that tracks moving targets. Developed originally for astronomical applications, the instrument utilizes an array of micromirrors to reflect light to a panchromatic imaging array. When an object of interest is detected the individual micromirrors imaging the object are tilted to reflect the light to a spectrometer to collect a full spectrum. This paper will present example sensor performance from empirical data collected in laboratory experiments, as well as our approach in designing optical and radiometric models of the MOS channels and the micromirror array. Simulation of moving vehicles in a highfidelity, hyperspectral scene is used to generate a dynamic video input for the adaptive sensor. Performance-driven algorithms for feature-aided target tracking and modality selection exploit multiple electromagnetic observables to track moving vehicle targets.

Catching the Light - The Entwined History of Light and Mind

NASA Astrophysics Data System (ADS)

Zajonc, Arthur

1995-04-01

In 1910, the surgeons Moreau and LePrince wrote about their successful operation on an eight-year-old boy who had been blind since birth because of cataracts. When the boy's eyes were healed they removed the bandages and, waving a hand in front of the child's physically perfect eyes, asked him what he saw. "I don't know," was his only reply. What he saw was only a varying brightness in front of him. However, when allowed to touch the hand as it began to move, he cried out in a voice of triumph, "It's moving!" He could feel it move, but he still needed laboriously to learn to see it move. Light and eyes were not enough to grant him sight. How, then, do we see? What's the difference between seeing and perception? What is light? From ancient times to the present, from philosophers to quantum physicists, nothing has so perplexed, so fascinated, so captivated the mind as the elusive definition of light. In Catching the Light , Arthur Zajonc takes us on an epic journey into history, tracing how humans have endeavored to understand the phenomenon of light. Blending mythology, religion, science, literature, and painting, Zajonc reveals in poetic detail the human struggle to identify the vital connection between the outer light of nature and the inner light of the human spirit. He explains the curiousness of the Greeks' blue and green "color blindness": Odysseus gazing longingly at the "wine-dark sea"; the use of chloros (green) as the color of honey in Homer's Odessey ; and Euripides' use of the color green to describe the hue of tears and blood. He demonstrates the complexity of perception through the work of Paul Cézanne--the artist standing on the bank of a river, painting the same scene over and over again, the motifs multiplying before his eyes. And Zajonc goes on to show how our quest for an understanding of light, as well as the conclusions we draw, reveals as much about the nature of our own psyche as it does about the nature of light itself. For the ancient Egyptians the nature of light was clear--it simply was the gaze of God. In the hands of the ancient Greeks, light had become the luminous inner fire whose ethereal effluence brought sight. In our contemporary world of modern quantum physics, science plays the greatest part in our theories of light's origin--from scientific perspectives such as Sir Isaac Newton's "corpuscular theory of light" and Michael Faraday's "lines of force" to such revolutionary ideas as Max Planck's "discrete motion of a pendulum" (the basis of quantum mechanics), Albert Einstein's "particles of light" and "theory of relativity," and Niels Bohr's "quantum jumps." Yet the metaphysical aspects of the scientific search, Zajonc shows, still loom large. For the physicist Richard Feynman, a quantum particle travels all paths, eventually distilling to one path whose action is least--the most beautiful path of all. Whatever light is, here is where we will find it. With rare clarity and unmatched lyricism, Zajonc illuminates the profound implications of the relationships between the multifaceted strands of human experience and scientific endeavor. A fascinating search into our deepest scientific mystery, Catching the Light is a brilliant synthesis that will both entertain and inform.

Metal Hydride Compression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Terry A.; Bowman, Robert; Smith, Barton

Conventional hydrogen compressors often contribute over half of the cost of hydrogen stations, have poor reliability, and have insufficient flow rates for a mature FCEV market. Fatigue associated with their moving parts including cracking of diaphragms and failure of seal leads to failure in conventional compressors, which is exacerbated by the repeated starts and stops expected at fueling stations. Furthermore, the conventional lubrication of these compressors with oil is generally unacceptable at fueling stations due to potential fuel contamination. Metal hydride (MH) technology offers a very good alternative to both conventional (mechanical) and newly developed (electrochemical, ionic liquid pistons) methodsmore » of hydrogen compression. Advantages of MH compression include simplicity in design and operation, absence of moving parts, compactness, safety and reliability, and the possibility to utilize waste industrial heat to power the compressor. Beyond conventional H2 supplies of pipelines or tanker trucks, another attractive scenario is the on-site generating, pressuring and delivering pure H 2 at pressure (≥ 875 bar) for refueling vehicles at electrolysis, wind, or solar generating production facilities in distributed locations that are too remote or widely distributed for cost effective bulk transport. MH hydrogen compression utilizes a reversible heat-driven interaction of a hydride-forming metal alloy with hydrogen gas to form the MH phase and is a promising process for hydrogen energy applications [1,2]. To deliver hydrogen continuously, each stage of the compressor must consist of multiple MH beds with synchronized hydrogenation & dehydrogenation cycles. Multistage pressurization allows achievement of greater compression ratios using reduced temperature swings compared to single stage compressors. The objectives of this project are to investigate and demonstrate on a laboratory scale a two-stage MH hydrogen (H 2) gas compressor with a feed pressure of >50 bar and a delivery pressure ≥ 875 bar of high purity H 2 gas using the scheme shown in Figure 1. Progress to date includes the selection of two candidate metal hydrides for each compressor stage, supplier engagement and synthesis of small samples, and the beginning of in-depth characterization of their thermodynamics, kinetics, and hydrogen capacities for optimal performance with respect to energy requirements and efficiency. Additionally, bed design trade studies are underway and will be finalized in FY18. Subsequently, the prototype two-stage compressor will be fabricated, assembled and experimentally evaluated in FY19.« less

Dust lanes in backlit galaxies: first results from the STARSMOG survey

NASA Astrophysics Data System (ADS)

Keel, William C.; Bradford, Sarah; Holwerda, Benne; Conselice, Christopher; Baldry, Ivan; Bland-Hawthorn, Jonathan; Driver, Simon P.; Dunne, Loretta; Liske, Jochen; Robotham, Aaron; Tuffs, Richard

2017-01-01

STARSMOG is an HST WFC3 snapshot survey of dust attenuation in overlapping backlit galaxies, planned to span the range of morphological type and luminosity of dust-rich galaxies. The target list came from the Galaxy Zoo and GAMA catalogs, imposing a minimum redshift difference to guarantee large line-of-sight separations, virtually eliminating scattering corrections and avoiding potentially distorted interacting systems. These include the first flocculent spirals studied with the occulting-galaxy approach. We present results from the geometrically most favorable subset of 9 pairs from the 54 observed STARSMOG systems. The data quality and intensity of background light let us map dust features with attenuations of only a few per cent in the red F606W band. Organized dust lanes show sharp outer boundaries in disks, and are absent in galaxies of late Hubble type. Many Sb-Sc disks show a dusty web of criss-crossing lanes, some nearly at right angles to the overall spiral pattern. Particularly favorable cases constraint the scale height of starlight in the foreground disks, through comparison of the light loss in regions with and without background light. The covering fraction of dust at various attenuation levels is consistent between barred and nonbarred spirals, although dust features may be more concentrated in azimuth when a bar is present (and concentrated in an annulus when a stellar resonance ring is seen). Together with our previous data on much more limited samples or at lower resolution,these results add to a picture where galaxies of similar morphology may have quite different attenuation patterns with radius for both arm and interarm dust.

Different amplitude and time distribution of the sound of light and classical music

NASA Astrophysics Data System (ADS)

Diodati, P.; Piazza, S.

2000-08-01

Several pieces of different musical kinds were studied measuring $N(A)$, the output amplitude of a peak detector driven by the electric signal arriving to the loudspeaker. Fixed a suitable threshold $\\bar{A}$, we considered $N(A)$, the number of times that $A(t)>\\bar{A}$, each of them we named event and $N(t)$, the distribution of times $t$ between two consecutive events. Some $N(A)$ and $N(t)$ distributions are displayed in the reported logarithmic plots, showing that jazz, pop, rock and other popular rhythms have noise-distribution, while classical pieces of music are characterized by more complex statistics. We pointed out the extraordinary case of the aria ``\\textit{La calunnia \\`{e} un venticello}'', where the words describe an avalanche or seismic process, calumny, and the rossinian music shows $N(A)$ and $N(t)$ distribution typical of earthquakes.

Aspects of spatial dispersion in the optical properties of a vacuum-dielectric interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, D.L.; Rimbey, P.R.

1976-09-15

We have examined the relationship between the polarizibility for a two-phase (vacuum-dielectric) system and the use of additional boundary conditions and the like, as regards the response of systems exhibiting spatial dispersion. As a consequence we are able to derive information about induced-charge and current densities and the continuity of the field quantities across the interface. It is shown that it is not possible to resonantly excite longitudinal bulk modes with incident light in the formalism of Rimbey-Mahan. We have derived sum rules in wave-vector space on bulk polaritions in homogeneous isotropic systems. In the case of nonhomogeneous perfect crystalsmore » in which the bulk response is described by the matrix epsilon-bar (Q, Q'), we have solved formally for the surface impedance in terms of an assumed arbitrary epsilon-bar (Q, Q'), by means of an extension of the Fuchs-Kliewer formalism. (AIP)« less

The DIRC front-end electronics chain for BaBar

NASA Astrophysics Data System (ADS)

Bailly, P.; Beigbeder, C.; Bernier, R.; Breton, D.; Bonneaud, G.; Caceres, T.; Chase, R.; Chauveau, J.; Del Buono, L.; Dohou, F.; Ducorps, A.; Gastaldi, F.; Genat, J. F.; Hrisoho, A.; Imbert, P.; Lebbolo, H.; Matricon, P.; Oxoby, G.; Renard, C.; Roos, L.; Sen, S.; Thiebaux, C.; Truong, K.; Tocut, V.; Vasileiadis, G.; Va'Vra, J.; Verderi, M.; Warner, D.; Wilson, R. J.; Wormser, G.; Zhang, B.; Zomer, F.

2000-12-01

Recent results from the Front-End electronics of the Detector of Internally Reflected Cerenkov light (DIRC) for the BaBar experiment at SLAC (Stanford, USA) are presented. It measures to better than 1 ns the arrival time of Cerenkov photoelectrons detected in a 11000 phototubes array and their amplitude spectra. It mainly comprises 64-channel DIRC Front-End Boards (DFB) equipped with eight full-custom analog chips performing zero-cross discrimination with 2 mV threshold and pulse shaping, four full-custom digital time to digital chips (TDC) for timing measurements with 500 ps binning and a readout logic selecting hits in the trigger window, and DIRC Crate Controller cards (DCC) serializing the data collected front up to 16 DFBs onto a 1.2 Gb/s optical link. Extensive test results of the pre-production chips are presented, as well as system tests.

A common neonicotinoid pesticide, thiamethoxam, alters honey bee activity, motor functions, and movement to light.

PubMed

Tosi, S; Nieh, J C

2017-11-09

Honey bees provide key ecosystem services. To pollinate and to sustain the colony, workers must walk, climb, and use phototaxis as they move inside and outside the nest. Phototaxis, orientation to light, is linked to sucrose responsiveness and the transition of work from inside to outside the nest, and is also a key component of division of labour. However, the sublethal effects of pesticides on locomotion and movement to light are relatively poorly understood. Thiamethoxam (TMX) is a common neonicotinoid pesticide that bees can consume in nectar and pollen. We used a vertical arena illuminated from the top to test the effects of acute and chronic sublethal exposures to TMX. Acute consumption (1.34 ng/bee) impaired locomotion, caused hyperactivity (velocity: +109%; time moving: +44%) shortly after exposure (30 min), and impaired motor functions (falls: +83%; time top: -43%; time bottom: +93%; abnormal behaviours: +138%; inability to ascend: +280%) over a longer period (60 min). A 2-day chronic exposure (field-relevant daily intakes of 1.42-3.48 ng/bee/day) impaired bee ability to ascend. TMX increased movement to light after acute and chronic exposure. Thus, TMX could reduce colony health by harming worker locomotion and, potentially, alter division of labour if bees move outside or remain outdoors.

Effective Light Directed Assembly of Building Blocks with Microscale Control.

PubMed

Dinh, Ngoc-Duy; Luo, Rongcong; Christine, Maria Tankeh Asuncion; Lin, Weikang Nicholas; Shih, Wei-Chuan; Goh, James Cho-Hong; Chen, Chia-Hung

2017-06-01

Light-directed forces have been widely used to pattern micro/nanoscale objects with precise control, forming functional assemblies. However, a substantial laser intensity is required to generate sufficient optical gradient forces to move a small object in a certain direction, causing limited throughput for applications. A high-throughput light-directed assembly is demonstrated as a printing technology by introducing gold nanorods to induce thermal convection flows that move microparticles (diameter = 40 µm to several hundreds of micrometers) to specific light-guided locations, forming desired patterns. With the advantage of effective light-directed assembly, the microfluidic-fabricated monodispersed biocompatible microparticles are used as building blocks to construct a structured assembly (≈10 cm scale) in ≈2 min. The control with microscale precision is approached by changing the size of the laser light spot. After crosslinking assembly of building blocks, a novel soft material with wanted pattern is approached. To demonstrate its application, the mesenchymal stem-cell-seeded hydrogel microparticles are prepared as functional building blocks to construct scaffold-free tissues with desired structures. This light-directed fabrication method can be applied to integrate different building units, enabling the bottom-up formation of materials with precise control over their internal structure for bioprinting, tissue engineering, and advanced manufacturing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Automated real-time detection of defects during machining of ceramics

DOEpatents

Ellingson, W.A.; Sun, J.

1997-11-18

Apparatus for the automated real-time detection and classification of defects during the machining of ceramic components employs an elastic optical scattering technique using polarized laser light. A ceramic specimen is continuously moved while being machined. Polarized laser light is directed onto the ceramic specimen surface at a fixed position just aft of the machining tool for examination of the newly machined surface. Any foreign material near the location of the laser light on the ceramic specimen is cleared by an air blast. As the specimen is moved, its surface is continuously scanned by the polarized laser light beam to provide a two-dimensional image presented in real-time on a video display unit, with the motion of the ceramic specimen synchronized with the data acquisition speed. By storing known ``feature masks`` representing various surface and sub-surface defects and comparing measured defects with the stored feature masks, detected defects may be automatically characterized. Using multiple detectors, various types of defects may be detected and classified. 14 figs.

Automated real-time detection of defects during machining of ceramics

DOEpatents

Ellingson, William A.; Sun, Jiangang

1997-01-01

Apparatus for the automated real-time detection and classification of defects during the machining of ceramic components employs an elastic optical scattering technique using polarized laser light. A ceramic specimen is continuously moved while being machined. Polarized laser light is directed onto the ceramic specimen surface at a fixed position just aft of the machining tool for examination of the newly machined surface. Any foreign material near the location of the laser light on the ceramic specimen is cleared by an air blast. As the specimen is moved, its surface is continuously scanned by the polarized laser light beam to provide a two-dimensional image presented in real-time on a video display unit, with the motion of the ceramic specimen synchronized with the data acquisition speed. By storing known "feature masks" representing various surface and sub-surface defects and comparing measured defects with the stored feature masks, detected defects may be automatically characterized. Using multiple detectors, various types of defects may be detected and classified.

A new linear structured light module based on the MEMS micromirror

NASA Astrophysics Data System (ADS)

Zhou, Peng; Shen, Wenjiang; Yu, Huijun

2017-10-01

A new linear structured light module based on the Micro-Electro-Mechanical System (MEMS) two-dimensional scanning micromirror was designed and created. This module consists of a laser diode, a convex lens, and the MEMS micromirror. The laser diode generates the light and the convex lens control the laser beam to converge on a single point with large depth of focus. The fast scan in horizontal direction of the micromirror will turn the laser spot into a homogenous laser line. Meanwhile, the slow scan in vertical direction of the micromirror will move the laser line in the vertical direction. The width of the line generated by this module is 300μm and the length is 120mm and the moving distance is 100mm at 30cm away from the module. It will promote the development of industrial detection.

Quantum channels from reflections on moving mirrors.

PubMed

Gianfelici, Giulio; Mancini, Stefano

2017-11-16

Light reflection on a mirror can be thought as a simple physical effect. However if this happens when the mirror moves a rich scenario opens up. Here we aim at analyzing it from a quantum communication perspective. In particular, we study the kind of quantum channel that arises from (Gaussian) light reflection upon an accelerating mirror. Two competing mechanisms emerge in such a context, namely photons production by the mirror's motion and interference between modes. As consequence we find out a quantum amplifier channel and quantum lossy channel respectively below and above a threshold frequency (that depends on parameters determining mirror's acceleration). Exactly at the threshold frequency the channel behaves like a purely classical additive channel, while it becomes purely erasure for large frequencies. In addition the time behavior of the channel is analyzed by employing wave packets expansion of the light field.

Feeding the Monster

NASA Astrophysics Data System (ADS)

2005-10-01

Near-infrared images of the active galaxy NGC 1097, obtained with the NACO adaptive optics instrument on ESO's Very Large Telescope, disclose with unprecedented detail a complex central network of filamentary structure spiralling down to the centre of the galaxy. These observations provide astronomers with new insights on how super-massive black holes lurking inside galaxies get fed. "This is possibly the first time that a detailed view of the channelling process of matter, from the main part of the galaxy down to the very end in the nucleus is released," says Almudena Prieto (Max-Planck Institute, Heidelberg, Germany), lead author of the paper describing these results. Located at a distance of about 45 million light-years in the southern constellation Fornax (the Furnace), NGC 1097 is a relatively bright, barred spiral galaxy seen face-on. At magnitude 9.5, and thus just 25 times fainter than the faintest object that can be seen with the unaided eye, it appears in small telescopes as a bright, circular disc. NGC 1097 is a very moderate example of an Active Galactic Nucleus (AGN), whose emission is thought to arise from matter (gas and stars) falling into oblivion in a central black hole. However, NGC 1097 possesses a comparatively faint nucleus only, and the black hole in its centre must be on a very strict "diet": only a small amount of gas and stars is apparently being swallowed by the black hole at any given moment. Astronomers have been trying to understand for a long time how the matter is "gulped" down towards the black hole. Watching directly the feeding process requires very high spatial resolution at the centre of galaxies. This can be achieved by means of interferometry as was done with the VLTI MIDI instrument on the central parts of another AGN, NGC 1068 (see ESO PR 17/03), or with adaptive optics [1]. Thus, astronomers [2] obtained images of NGC 1097 with the adaptive optics NACO instrument attached to Yepun, the fourth Unit Telescope of ESO's VLT. These new images probe with unprecedented detail the presence and extent of material in the very proximity of the nucleus. The resolution achieved with the images is about 0.15 arcsecond, corresponding to about 30 light-years across. For comparison, this is only 8 times the distance between the Sun and its nearest star, Proxima Centauri. ESO PR Photo 33b/05 ESO PR Photo 33b/05 Filamentary Structures in NGC 1097 [Preview - JPEG: 400 x 570 pix - 275k] [Normal - JPEG: 800 x 1140 pix - 900k] [Full Res - JPEG: 1422 x 2026 pix - 2.6M] Caption: ESO PR Photo 33b/05: The left image shows the same central region as imaged in PR Photo 33a/05 but this time as seen in the J-Ks colour. It clearly shows the nucleus, the central spiral arms extending up to 1,300 light-years from the centre, and the star-forming ring. The right image shows the same but after a masking process has been applied to suppress the central stellar light of the galaxy. The central spiral arms are now seen as dark channels, some extending up to the star-forming ring. North is up and East is to the left. As can be seen in last year's image (see ESO PR Photo 35d/04), NGC 1097 has a very strong bar and a prominent star-forming ring inside it. Interior to the ring, a secondary bar crosses the nucleus almost perpendicular to the primary bar. The newly released NACO near-infrared images show in addition more than 300 star-forming regions, a factor four larger than previously known from Hubble Space Telescope images. These "HII regions" can be seen as white spots in ESO PR Photo 33a/05. At the centre of the ring, a moderate active nucleus is located. Details from the nucleus and its immediate surroundings are however outshone by the overwhelming stellar light of the galaxy seen as the bright diffuse emission all over the image. The astronomers therefore applied a masking technique that allowed them to suppress the stellar light (see ESO PR Photo 33b/05). This unveils a bright nucleus at the centre, but mostly a complex central network of filamentary structures spiralling down to the centre. "Our analysis of the VLT/NACO images of NGC 1097 shows that these filaments end up at the very centre of the galaxy", says co-author Juha Reunanen from ESO. "This network closely resembles those seen in computer models", adds co-worker Witold Maciejewski from the University of Oxford, UK. "The nuclear filaments revealed in the NACO images are the tracers of cold dust and gas being channelled towards the centre to eventually ignite the AGN." The astronomers also note that the curling of the spiral pattern in the innermost 300 light-years seem indeed to confirm the presence of a super-massive black hole in the centre of NGC 1097. Such a black hole in the centre of a galaxy causes the nuclear spiral to wind up as it approaches the centre, while in its absence the spiral would be unwinding as it moves closer to the centre. An image of NGC 1097 and its small companion, NGC 1097A, was taken in December 2004, in the presence of Chilean President Lagos with the VIMOS instrument on ESO's Very Large Telescope (VLT). It is available as ESO PR Photo 35d/04. More information This ESO Press Photo is based on research published in the October issue of Astronomical Journal, vol. 130, p. 1472 ("Feeding the Monster: The Nucleus of NGC 1097 at Subarcsecond Scales in the Infrared with the Very Large Telescope", by M. Almudena Prieto, Witold Maciejewski, and Juha Reunanen).

Six-degree-of-freedom parallel minimanipulator with three inextensible limbs

NASA Technical Reports Server (NTRS)

Tahmasebi, Farhad (Inventor); Tsai, Lung-Wen (Inventor)

1994-01-01

A Six-Degree-of-Freedom Parallel-Manipulator having three inextensible limbs for manipulating a platform is described. The three inextensible limbs are attached via universal joints to the platform at non-collinear points. Each of the inextensible limbs is also attached via universal joints to a two-degree-of-freedom parallel driver such as a five-bar linkage, a pantograph, or a bidirectional linear stepper motor. The drivers move the lower ends of the limbs parallel to a fixed base and thereby provide manipulation of the platform. The actuators are mounted on the fixed base without using any power transmission devices such as gears or belts.

Optical Measurement Technology For Aluminium Extrusions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moe, Per Thomas; Willa-Hansen, Arnfinn; Stoeren, Sigurd

2007-04-07

Optical measurement techniques such as laser scanning, structured light scanning and photogrammetry can be used for accurate shape control for aluminum extrusion and downstream processes. The paper presents the fundamentals of optical shape measurement. Furthermore, it focuses on how full-field in- and off-line shape measurement during pure-bending of aluminum extrusions has been performed with stripe projection (structured light) using white light. Full field shape measurement is difficult to implement industrially, but is very useful as a laboratory tool. For example, it has been clearly shown how moderate internal air pressure (less than 5 bars) can significantly reduce undesirable cross-sectional shapemore » distortions during pure bending, and how buckling of the compressive flange occurs at an early stage. Finally, a stretch-bending set-up with adaptive shape control using internal gas pressure and optical techniques is presented.« less

The descriptive epidemiology of local restaurant smoking regulations in Massachusetts: an analysis of the protection of restaurant customers and workers.

PubMed

Skeer, M; Siegel, M

2003-06-01

To describe the range of restaurant smoking regulations in the 351 cities and towns in Massachusetts, and to analyse the level of protection from secondhand smoke exposure guaranteed by these regulations. We obtained the local restaurant smoking regulations for each town, analysing them in terms of the protection of restaurant workers, bar workers, and adult and youth restaurant customers. The percentage of restaurant patrons and workers and bar workers who are protected from secondhand smoke exposure by the current smoking regulations in Massachusetts. As of June 2002, 225 towns had local restaurant smoking regulations. Of these, 69 (30.7%) do not allow smoking in restaurants, 10 (4.4%) restrict smoking to adult only restaurants, 64 (28.4%) restrict smoking to enclosed, separately ventilated areas, and 82 (36.4%) restrict smoking to areas that need not be enclosed and separately ventilated. Of the 174 towns that, at a minimum, restrict smoking to bar areas or separately ventilated areas, 35 (20.1%) allow variances. Overall, 60 towns, covering only 17.7% of the population, completely ban smoking in restaurants. As a result, 81.3% of adult restaurant customers, 81.2% of youth customers, 82.3% of restaurant workers, and 87.0% of bar workers are not guaranteed protection from secondhand smoke in restaurants. Despite the widespread adoption of local restaurant smoking regulations in Massachusetts, the majority of restaurant customers and workers remain unprotected from secondhand smoke exposure. In light of this, public health practitioners must stop compromising the protection of customers and workers from secondhand smoke exposure in restaurants.

An intervention to reduce sitting and increase light-intensity physical activity at work: Design and rationale of the ‘Stand & Move at Work’ group randomized trial

PubMed Central

Buman, Matthew P.; Mullane, Sarah L.; Toledo, Meynard J.; Rydell, Sarah A.; Gaesser, Glenn A.; Crespo, Noe C.; Hannan, Peter; Feltes, Linda; Vuong, Brenna; Pereira, Mark A

2016-01-01

Background American workers spend 70–80% of their time at work being sedentary. Traditional approaches to increase moderate-vigorous physical activity (MVPA) may be perceived to be harmful to productivity. Approaches that target reductions in sedentary behavior and/or increases in standing or light-intensity physical activity [LPA] may not interfere with productivity and may be more feasible to achieve through small changes accumulated throughout the workday. Methods/Design This group randomized trial (i.e., cluster randomized trial) will test the relative efficacy of two sedentary behavior focused interventions in 24 worksites across two states (N=720 workers). The MOVE+ intervention is a multilevel individual, social, environmental, and organizational intervention targeting increases in light-intensity physical activity in the workplace. The STAND+ intervention is the MOVE+ intervention with the addition of the installation and use of sit-stand workstations to reduce sedentary behavior and enhance light-intensity physical activity opportunities. Our primary outcome will be objectively-measured changes in sedentary behavior and light-intensity physical activity over 12 months, with additional process measures at 3 months and longer-term sustainability outcomes at 24 months. Our secondary outcomes will be a clustered cardiometabolic risk score (comprised of fasting glucose, insulin, triglycerides, HDL-cholesterol, and blood pressure), workplace productivity, and job satisfaction. Discussion This study will determine the efficacy of a multilevel workplace intervention (including the use of a sit-stand workstation) to reduce sedentary behavior and increase LPA and concomitant impact on cardiometabolic health, workplace productivity, and satisfaction. PMID:27940181

Direction selectivity in the larval zebrafish tectum is mediated by asymmetric inhibition.

PubMed

Grama, Abhinav; Engert, Florian

2012-01-01

The extraction of the direction of motion is an important computation performed by many sensory systems and in particular, the mechanism by which direction-selective retinal ganglion cells (DS-RGCs) in the retina acquire their selective properties, has been studied extensively. However, whether DS-RGCs simply relay this information to downstream areas or whether additional and potentially de novo processing occurs in these recipient structures is a matter of great interest. Neurons in the larval zebrafish tectum, the largest retino-recipent area in this animal, show direction-selective (DS) responses to moving visual stimuli but how these properties are acquired is still unknown. In order to study this, we first used two-photon calcium imaging to classify the population responses of tectal cells to bars moving at different speeds and in different directions. Subsequently, we performed in vivo whole cell electrophysiology on these DS tectal neurons and we found that their inhibitory inputs were strongly biased toward the null direction of motion, whereas the excitatory inputs showed little selectivity. In addition, we found that excitatory currents evoked by a stimulus moving in the preferred direction occurred before the inhibitory currents whereas a stimulus moving in the null direction evoked currents in the reverse temporal order. The membrane potential modulations resulting from these currents were enhanced by the spike generation mechanism to generate amplified direction selectivity in the spike output. Thus, our results implicate a local inhibitory circuit in generating direction selectivity in tectal neurons.

Direction selectivity in the larval zebrafish tectum is mediated by asymmetric inhibition

PubMed Central

Grama, Abhinav; Engert, Florian

2012-01-01

The extraction of the direction of motion is an important computation performed by many sensory systems and in particular, the mechanism by which direction-selective retinal ganglion cells (DS-RGCs) in the retina acquire their selective properties, has been studied extensively. However, whether DS-RGCs simply relay this information to downstream areas or whether additional and potentially de novo processing occurs in these recipient structures is a matter of great interest. Neurons in the larval zebrafish tectum, the largest retino-recipent area in this animal, show direction-selective (DS) responses to moving visual stimuli but how these properties are acquired is still unknown. In order to study this, we first used two-photon calcium imaging to classify the population responses of tectal cells to bars moving at different speeds and in different directions. Subsequently, we performed in vivo whole cell electrophysiology on these DS tectal neurons and we found that their inhibitory inputs were strongly biased toward the null direction of motion, whereas the excitatory inputs showed little selectivity. In addition, we found that excitatory currents evoked by a stimulus moving in the preferred direction occurred before the inhibitory currents whereas a stimulus moving in the null direction evoked currents in the reverse temporal order. The membrane potential modulations resulting from these currents were enhanced by the spike generation mechanism to generate amplified direction selectivity in the spike output. Thus, our results implicate a local inhibitory circuit in generating direction selectivity in tectal neurons. PMID:22969706

Feature-selective attention in healthy old age: a selective decline in selective attention?

PubMed

Quigley, Cliodhna; Müller, Matthias M

2014-02-12

Deficient selection against irrelevant information has been proposed to underlie age-related cognitive decline. We recently reported evidence for maintained early sensory selection when older and younger adults used spatial selective attention to perform a challenging task. Here we explored age-related differences when spatial selection is not possible and feature-selective attention must be deployed. We additionally compared the integrity of feedforward processing by exploiting the well established phenomenon of suppression of visual cortical responses attributable to interstimulus competition. Electroencephalogram was measured while older and younger human adults responded to brief occurrences of coherent motion in an attended stimulus composed of randomly moving, orientation-defined, flickering bars. Attention was directed to horizontal or vertical bars by a pretrial cue, after which two orthogonally oriented, overlapping stimuli or a single stimulus were presented. Horizontal and vertical bars flickered at different frequencies and thereby elicited separable steady-state visual-evoked potentials, which were used to examine the effect of feature-based selection and the competitive influence of a second stimulus on ongoing visual processing. Age differences were found in feature-selective attentional modulation of visual responses: older adults did not show consistent modulation of magnitude or phase. In contrast, the suppressive effect of a second stimulus was robust and comparable in magnitude across age groups, suggesting that bottom-up processing of the current stimuli is essentially unchanged in healthy old age. Thus, it seems that visual processing per se is unchanged, but top-down attentional control is compromised in older adults when space cannot be used to guide selection.

Partial recovery of hemiparesis following hemispherectomy in infant monkeys.

PubMed

Burke, Mark W; Zangenehpour, Shahin; Ptito, Maurice

2010-01-22

Hemiparesis, unilateral weakness or partial paralysis, is a common outcome following hemispherectomy in humans. We use the non-human primate as an invaluable translational model for our understanding of developmental plasticity in response to hemispherectomy. Three infant vervet monkeys (Chlorocebus sabeus) underwent hemispherectomy at a median age of 9 weeks and two additional monkeys at 48 months. Gross motor assessment was conducted in a large open field that contained a horizontal bar spanning the width of the cage. Subjects were assessed yearly following surgery in infantile lesions for a period of 3 years. Adult-lesioned subjects were assessed 40 months following surgery. Shortly after surgery both infant and adult-lesioned subjects were unable to move the contralateral side of their body, but all subjects were able to walk within 6 months following surgery. At each time point the lower limb gait was normal in infant-lesioned subjects with no apparent limp or dragging, however the upper limb demonstrated significant impairment. Horizontal bar crossing was significantly impaired during the first 24 months following surgery. Adult-lesioned subjects also displayed upper limb movement impairments similar to infant-lesioned subjects. In addition the adult-lesioned subjects displayed a noticeable lower limb limp, which was not observed in the infant-lesioned group. Both groups at each time point showed a propensity for ipsiversive turning. The upper limb gait impairment and horizontal bar crossing of lesioned subjects are reminiscent of hemiparesis seen in hemisperectomized humans with the young-lesioned subjects showing a greater propensity for recovery. (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Microbial survey of ready-to-eat salad ingredients sold at retail reveals the occurrence and the persistence of Listeria monocytogenes Sequence Types 2 and 87 in pre-packed smoked salmon.

PubMed

Chau, Man Ling; Aung, Kyaw Thu; Hapuarachchi, Hapuarachchige Chanditha; Lee, Pei Sze Valarie; Lim, Pei Ying; Kang, Joanne Su Lin; Ng, Youming; Yap, Hooi Ming; Yuk, Hyun-Gyun; Gutiérrez, Ramona Alikiiteaga; Ng, Lee Ching

2017-02-28

As the preparation of salads involves extensive handling and the use of uncooked ingredients, they are particularly vulnerable to microbial contamination. This study aimed to determine the microbial safety and quality of pre-packed salads and salad bar ingredients sold in Singapore, so as to identify public health risks that could arise from consuming salads and to determine areas for improvement in the management of food safety. The most frequently encountered organism in pre-packed salad samples was B. cereus, particularly in pasta salads (33.3%, 10/30). The most commonly detected organism in salad bar ingredients was L. monocytogenes, in particular seafood ingredients (44.1%, 15/34), largely due to contaminated smoked salmon. Further investigation showed that 21.6% (37/171) of the pre-packed smoked salmon sold in supermarkets contained L. monocytogenes. Significantly higher prevalence of L. monocytogenes and higher Standard Plate Count were detected in smoked salmon at salad bars compared to pre-packed smoked salmon in supermarkets, which suggested multiplication of the organism as the products move down the supply chain. Further molecular analysis revealed that L. monocytogenes Sequence Type (ST) 2 and ST87 were present in a particular brand of pre-packed salmon products over a 4-year period, implying a potential persistent contamination problem at the manufacturing level. Our findings highlighted a need to improve manufacturing and retail hygiene processes as well as to educate vulnerable populations to avoid consuming food prone to L. monocytogenes contamination.

A Novel Light Trapping Phenomenon in Fluid Media.

ERIC Educational Resources Information Center

Devlin, J. C.; Tolles, W. M.

1979-01-01

Describes an experiment on light trapping in thin liquid films. Injection of a thin layer of solution at the boundary of a moving solvent is utilized to create a thin fluid sheet having an index of refraction greater than that of the surrounding medium. (Author/SA)

Light-Steered Isotropic Semiconductor Micromotors.

PubMed

Chen, Chuanrui; Mou, Fangzhi; Xu, Leilei; Wang, Shaofei; Guan, Jianguo; Feng, Zunpeng; Wang, Quanwei; Kong, Lei; Li, Wei; Wang, Joseph; Zhang, Qingjie

2017-01-01

Intelligent photoresponsive isotropic semiconductor micromotors are developed by taking advantage of the limited penetration depth of light to induce asymmetrical surface chemical reactions. Independent of the Brownian motion of themselves, the as-proposed isotropic micromotors are able to continuously move with both motion direction and speed just controlled by light, as well as precisely manipulate particles for nanoengineering. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Angry Birds in Space

NASA Astrophysics Data System (ADS)

Halford, A. J.

2017-12-01

When space computers first started listening into space radio, they noticed that there were radio noises that happened on the morning side of the Earth. Because these waves sounded like noises birds make in the morning, we named these waves after them. These bird sounding waves can move around the Earth, flying up and down, and sometimes move into an area where there is more stuff. This area is also much colder than where these bird noises are first made. When the waves move into this cold area where there is more stuff, they start to sound like angry birds instead of happy birds. Both of these waves, the happy and angry bird sounding waves, are very important to our understanding of how the tiny things in space move and change. Sometimes the waves which sound like birds can push these tiniest of things into the sky. The happy bird sounding waves can push the tiniest things quickly while the angry bird sounding waves push the tinest of things more slowly. When the tiny things fall into the sky, they create beautiful space lights and light that burns which can hurt people in up goers and not so up goers as well as our things like phones, and space computers. We study these waves that sound like birds to better understand when and where the tiny things will fall. That way we can be prepared and enjoy watching the pretty space lights at night with no worries.

High Power Laser Diode Array Qualification and Guidelines for Space Flight Environments

NASA Technical Reports Server (NTRS)

Eegholm, Niels; Ott, Melanie; Stephen, Mark; Leidecker, Henning

2005-01-01

Semiconductor laser diodes emit coherent light by simulated emission generated inside the cavity formed by the cleaved end facets of a slab of semiconductor that is typically less than a millimeter in any dimension for single emitters. The diode is pumped by current injection in the p-n junction through the metallic contacts. Laser diodes emitting in the range of 0.8 micron to 1.06 micron have a wide variety of applications from pumping erbium doped fiber amplifiers, dual-clad fiber lasers, solid-state lasers used in telecom, aerospace, military, medical purposes and all the way to CD players, laser printers and other consumer and industrial products. Laser diode bars have many single emitters side by side and spaced approximately .5 mm on a single slab of semiconductor material approximately .5 mm x 10 mm. The individual emitters are connected in parallel maintaining the voltage at -2V but increasing the current to 50-100A/bar. Stacking these laser diode bars in multiple layers, 2 to 20+ high, yields high power laser diode arrays capable of emitting several hundreds of Watts. Electrically the bars are wired in series increasing the voltage by 2V/bar but maintaining the total current at 50-100A. These arrays are one of the enabling technologies for efficient, high power solid-state lasers. Traditionally these arrays are operated in QCW (Quasi CW) mode with pulse widths 10-200 (mu)s and with repetition rates of 10-200Hz. In QCW mode the wavelength and the output power of the laser reaches steady-state but the temperature does not. The advantage is a substantially higher output power than in CW mode, where the output power would be limited by the internal heating and hence the thermal and heat sinking properties of the device. The down side is a much higher thermal induced mechanical stress caused by the constant heating and cooling cycle inherent to the QCW mode.

HUBBLE SEES CHANGES IN GAS SHELL AROUND NOVA CYGNI 1992

NASA Technical Reports Server (NTRS)

2002-01-01

The European Space Agency's ESA Faint Object Camera utilizing the corrective optics provided by NASA's COSTAR (Corrective Optics Space Telescope Axial Replacement), has given astronomers their best look yet at a rapidly ballooning bubble of gas blasted off a star. The shell surrounds Nova Cygni 1992, which erupted on February 19, 1992. A nova is a thermonuclear explosion that occurs on the surface of a white dwarf star in a double star system. The new HST image [right] reveals an elliptical and slightly lumpy ring-like structure. The ring is the edge of a bubble of hot gas blasted into space by the nova. The shell is so thin that the FOC does not resolve its true thickness, even with HST's restored vision. An HST image taken on May 31 1993, [left] 467 days after the explosion, provided the first glimpse of the ring and a mysterious bar-like structure. But the image interpretation was severely hampered by HST's optical aberration, that scattered light from the central star which contaminated the ring's image. A comparison of the pre and post COSTAR/FOC images reveals that the ring has evolved in the seven months that have elapsed between the two observations. The ring has expanded from a diameter of approximately 74 to 96 billion miles. The bar-like structure seen in the earlier HST image has disappear. These changes might confirm theories that the bar was produced by a dense layer of gas thrown off in the orbital plane of the double star system. The gas has subsequently grown more tenuous and so the bar has faded. The ring has also grown noticeably more oblong since the earlier image. This suggests the hot gas is escaping more rapidly above and below the system's orbital plane. As the gas continues escaping the ring should grow increasingly egg-shaped in the coming years. HST's newly improved sensitivity and high resolution provides a unique opportunity to understand the novae by resolving the effects of the explosion long before they can be resolved in ground based telescopes. Nova Cygni is 10,430 light years away (as measured directly from the ring's diameter), and located in the summer constellation Cygnus the Swan. Credit: F. Paresce, R. Jedrzejewski (STScI) NASA/ESA PHOTO RELEASE NO.: STScI-PR94-06

Structural properties of faint low surface brightness galaxies

NASA Astrophysics Data System (ADS)

Pahwa, Isha; Saha, Kanak

2018-05-01

We study the structural properties of Low Surface Brightness galaxies (LSB) using a sample of 263 galaxies observed by the Green Bank Telescope (Schneider et al. 1992). We perform 2D decompositions of these galaxies in the SDSS g, r and i bands using the GALFIT software. Our decomposition reveals that about 60% of these galaxies are bulgeless i.e., their light distributions are well modelled by pure exponential disks. The rest of the galaxies were fitted with two components: a Sersic bulge and an exponential disk. Most of these galaxies have bulge-to-total (B/T) ratio less than 0.1. However, of these 104 galaxies, 20% have B/T > 0.1 i.e., hosting significant bulge component and they are more prominent amongst the fainter LSBs. According to g - r colour criteria, most of the LSB galaxies in our sample are blue, with only 7 classified as red LSBs. About 15% of the LSB galaxies (including both blue and red) in our sample host stellar bars. The incidence of bars is more prominent in relatively massive blue LSB galaxies with very high gas fraction. These findings may provide important clues to the formation and evolution of LSB galaxies - in particular on the bar/bulge formation in faint LSB disks.

Single top quark production as a probe of anomalous tqγ and tqZ couplings at the FCC-ee

NASA Astrophysics Data System (ADS)

Khanpour, Hamzeh; Khatibi, Sara; Yanehsari, Morteza Khatiri; Najafabadi, Mojtaba Mohammadi

2017-12-01

In this paper, a detailed study to probe the top quark Flavour-Changing Neutral Currents (FCNC) tqγ and tqZ at the future e-e+ collider FCC-ee in two different center-of-mass energies of 240 and 350 GeV is presented. A set of useful variables are proposed and used in a multivariate technique to separate signal e-e+ → Z / γ → t q bar (t bar q) from Standard Model background processes. The study includes a fast detector simulation based on the DELPHES package to consider the detector effects. The upper limits on the FCNC branching ratios at 95% confidence level (CL) in terms of the integrated luminosity are presented. It is shown that with 300 fb-1 of integrated luminosity of data, FCC-ee would be able to exclude the effective coupling strengths above O (10-4 -10-5) which is corresponding to branching fraction of O (0.01 - 0.001)%. We show that moving to a high-luminosity regime leads to a significant improvement on the upper bounds on the top quark FCNC couplings to a photon or a Z boson.

Percentiles of the run-length distribution of the Exponentially Weighted Moving Average (EWMA) median chart

NASA Astrophysics Data System (ADS)

Tan, K. L.; Chong, Z. L.; Khoo, M. B. C.; Teoh, W. L.; Teh, S. Y.

2017-09-01

Quality control is crucial in a wide variety of fields, as it can help to satisfy customers’ needs and requirements by enhancing and improving the products and services to a superior quality level. The EWMA median chart was proposed as a useful alternative to the EWMA \\bar{X} chart because the median-type chart is robust against contamination, outliers or small deviation from the normality assumption compared to the traditional \\bar{X}-type chart. To provide a complete understanding of the run-length distribution, the percentiles of the run-length distribution should be investigated rather than depending solely on the average run length (ARL) performance measure. This is because interpretation depending on the ARL alone can be misleading, as the process mean shifts change according to the skewness and shape of the run-length distribution, varying from almost symmetric when the magnitude of the mean shift is large, to highly right-skewed when the process is in-control (IC) or slightly out-of-control (OOC). Before computing the percentiles of the run-length distribution, optimal parameters of the EWMA median chart will be obtained by minimizing the OOC ARL, while retaining the IC ARL at a desired value.

Telescoping magnetic ball bar test gage

DOEpatents

Bryan, J.B.

1982-03-15

A telescoping magnetic ball bar test gage for determining the accuracy of machine tools, including robots, and those measuring machines having non-disengagable servo drives which cannot be clutched out. Two gage balls are held and separated from one another by a telescoping fixture which allows them relative radial motional freedom but not relative lateral motional freedom. The telescoping fixture comprises a parallel reed flexure unit and a rigid member. One gage ball is secured by a magnetic socket knuckle assembly which fixes its center with respect to the machine being tested. The other gage ball is secured by another magnetic socket knuckle assembly which is engaged or held by the machine in such manner that the center of that ball is directed to execute a prescribed trajectory, all points of which are equidistant from the center of the fixed gage ball. As the moving ball executes its trajectory, changes in the radial distance between the centers of the two balls caused by inaccuracies in the machine are determined or measured by a linear variable differential transformer (LVDT) assembly actuated by the parallel reed flexure unit. Measurements can be quickly and easily taken for multiple trajectories about several different fixed ball locations, thereby determining the accuracy of the machine.

Computer modeling of dynamic necking in bars

NASA Astrophysics Data System (ADS)

Partom, Yehuda; Lindenfeld, Avishay

2017-06-01

Necking of thin bodies (bars, plates, shells) is one form of strain localization in ductile materials that may lead to fracture. The phenomenon of necking has been studied extensively, initially for quasistatic loading and then also for dynamic loading. Nevertheless, many issues concerning necking are still unclear. Among these are: 1) is necking a random or deterministic process; 2) how does the specimen choose the final neck location; 3) to what extent do perturbations (material or geometrical) influence the neck forming process; and 4) how do various parameters (material, geometrical, loading) influence the neck forming process. Here we address these issues and others using computer simulations with a hydrocode. Among other things we find that: 1) neck formation is a deterministic process, and by changing one of the parameters influencing it monotonously, the final neck location moves monotonously as well; 2) the final neck location is sensitive to the radial velocity of the end boundaries, and as motion of these boundaries is not fully controlled in tests, this may be the reason why neck formation is sometimes regarded as a random process; and 3) neck formation is insensitive to small perturbations, which is probably why it is a deterministic process.

Alert Response to Motion Onset in the Retina

PubMed Central

Chen, Eric Y.; Marre, Olivier; Fisher, Clark; Schwartz, Greg; Levy, Joshua; da Silveira, Rava Azeredo

2013-01-01

Previous studies have shown that motion onset is very effective at capturing attention and is more salient than smooth motion. Here, we find that this salience ranking is present already in the firing rate of retinal ganglion cells. By stimulating the retina with a bar that appears, stays still, and then starts moving, we demonstrate that a subset of salamander retinal ganglion cells, fast OFF cells, responds significantly more strongly to motion onset than to smooth motion. We refer to this phenomenon as an alert response to motion onset. We develop a computational model that predicts the time-varying firing rate of ganglion cells responding to the appearance, onset, and smooth motion of a bar. This model, termed the adaptive cascade model, consists of a ganglion cell that receives input from a layer of bipolar cells, represented by individual rectified subunits. Additionally, both the bipolar and ganglion cells have separate contrast gain control mechanisms. This model captured the responses to our different motion stimuli over a wide range of contrasts, speeds, and locations. The alert response to motion onset, together with its computational model, introduces a new mechanism of sophisticated motion processing that occurs early in the visual system. PMID:23283327

Use of Statistical Analysis of Acoustic Emission Data on Carbon-Epoxy COPV Materials-of-Construction for Enhanced Felicity Ratio Onset Determination

NASA Technical Reports Server (NTRS)

Abraham, Arick Reed A.; Johnson, Kenneth L.; Nichols, Charles T.; Saulsberry, Regor L.; Waller, Jess M.

2012-01-01

Broadband modal acoustic emission (AE) data were acquired during intermittent load hold tensile test profiles on Toray T1000G carbon fiber-reinforced epoxy (C/Ep) single tow specimens. A novel trend seeking statistical method to determine the onset of significant AE was developed, resulting in more linear decreases in the Felicity ratio (FR) with load, potentially leading to more accurate failure prediction. The method developed uses an exponentially weighted moving average (EWMA) control chart. Comparison of the EWMA with previously used FR onset methods, namely the discrete (n), mean (n (raised bar)), normalized (n%) and normalized mean (n(raised bar)%) methods, revealed the EWMA method yields more consistently linear FR versus load relationships between specimens. Other findings include a correlation between AE data richness and FR linearity based on the FR methods discussed in this paper, and evidence of premature failure at lower than expected loads. Application of the EWMA method should be extended to other composite materials and, eventually, composite components such as composite overwrapped pressure vessels. Furthermore, future experiments should attempt to uncover the factors responsible for infant mortality in C/Ep strands.

Particulate Matter Speciation Profiles for Light-duty Gasoline Vehicles in the United States

EPA Science Inventory

Representative particulate matter (PM2.5) profiles for particles less than or equal to 2.5 micrometers are estimated from the Kansas City Light-Duty Vehicle Emissions Study for use in the US EPA’s vehicle emission model, the Motor Vehicle Emission Simulator (MOVES). The profiles ...

White light velocity interferometer

DOEpatents

Erskine, D.J.

1999-06-08

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

Multiple-Fiber-Optic Probe For Light-Scattering Measurements

NASA Technical Reports Server (NTRS)

Dhadwal, Harbans Singh; Ansari, Rafat R.

1996-01-01

Multiple-fiber-optical probe developed for use in measuring light scattered at various angles from specimens of materials. Designed for both static and dynamic light-scattering measurements of colloidal dispersions. Probe compact, rugged unit containing no moving parts and remains stationary during operation. Not restricted to operation in controlled, research-laboratory environment. Positioned inside or outside light-scattering chamber. Provides simultaneous measurements at small angular intervals over range of angles, made to include small scattering angles by orienting probe in appropriate direction.

Pressure-sensitive optrode

DOEpatents

Hirschfeld, T.B.

1985-04-09

An apparatus and method are disclosed for sensing changes in pressure and for generating optical signals related to changes in pressure. Light from a fiber optic is directed to a movable surface which is coated with a light-responsive material, and which moves relative to the end of the fiber optic in response to changes in pressure. The same fiber optic collects a portion of the reflected or emitted light from the movable surface. Changes in pressure are determined by measuring changes in the amount of light collected. 5 figs.

Achromatic phase-matching second harmonic generation for a tunable laser

DOEpatents

Jacobson, A.G.; Bisson, S.; Trebino, R.

1998-01-20

An optical system uses a nonlinear optical medium to alter the frequency of a relatively narrow band light source tunable over a plurality of different frequencies using an optical system for passively directing light to the nonlinear medium at a correct phase matching angle. In this manner, the light from the tunable light source can be efficiently frequency-doubled or frequency-tripled without the need of moving parts. An all prism design provides a system of optimal efficiency. 6 figs.

Achromatic phase-matching second harmonic generation for a tunable laser

DOEpatents

Jacobson, Alexander Gerson; Bisson, Scott; Trebino, Rick

1998-01-01

An optical system uses a nonlinear optical medium to alter the frequency of a relatively narrow band light source tunable over a plurality of different frequencies using an optical system for passively directing light to the nonlinear medium at a correct phase matching angle. In this manner, the light from the tunable light source can be efficiently frequency-doubled or frequency-tripled without the need of moving parts. An all prism design provides a system of optimal efficiency.

White light velocity interferometer

DOEpatents

Erskine, David J.

1997-01-01

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

White light velocity interferometer

DOEpatents

Erskine, David J.

1999-01-01

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

White light velocity interferometer

DOEpatents

Erskine, D.J.

1997-06-24

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

Dynamic Optical Grating Device and Associated Method for Modulating Light

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Chu, Sang-Hyon (Inventor)

2012-01-01

A dynamic optical grating device and associated method for modulating light is provided that is capable of controlling the spectral properties and propagation of light without moving mechanical components by the use of a dynamic electric and/or magnetic field. By changing the electric field and/or magnetic field, the index of refraction, the extinction coefficient, the transmittivity, and the reflectivity fo the optical grating device may be controlled in order to control the spectral properties of the light reflected or transmitted by the device.

Motion compensation for structured light sensors

NASA Astrophysics Data System (ADS)

Biswas, Debjani; Mertz, Christoph

2015-05-01

In order for structured light methods to work outside, the strong background from the sun needs to be suppressed. This can be done with bandpass filters, fast shutters, and background subtraction. In general this last method necessitates the sensor system to be stationary during data taking. The contribution of this paper is a method to compensate for the motion if the system is moving. The key idea is to use video stabilization techniques that work even if the illuminator is switched on and off from one frame to another. We used OpenCV functions and modules to implement a robust and efficient method. We evaluated it under various conditions and tested it on a moving robot outdoors. We will demonstrate that one can not only do 3D reconstruction under strong ambient light, but that it is also possible to observe optical properties of the objects in the environment.

Multipoint photonic doppler velocimetry using optical lens elements

DOEpatents

Frogget, Brent Copely; Romero, Vincent Todd

2014-04-29

A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Combs, S.K.; Milora, S.L.; Foust, C.R.

1989-05-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities (>2 km/s) are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-1 volume (less than or equal to55 bar) provides the gas to accelerate a 25.4-mm-diam piston in a 1-m-long pump tube; a burst disk or a fast valve initiates the accelerationmore » process in the first stage. As the piston travels the length of the pump tube, the downstream gas (initially at <1 bar) is compressed (to pressures up to 2600 bar) and thus is driven to high temperature (approx. =5000 K). This provides the driving force for acceleration of a 4-mm pellet in a 1-m-long gun barrel. In preliminary tests using helium as the driver in both stages, 35-mg plastic pellets have been accelerated to speeds as high as 4.0 km/s. Projectiles composed of hydrogen ice will have a mass in the range from 5 to 20 mg ( rhoapprox. =0.087, 0.20, and 0.32 g/cm/sup 3/ for frozen hydrogen isotopes). However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of approx. =3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications.« less

Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Combs, S.K.; Milora, S.L.; Foust, C.R.

1988-01-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities (>2 km/s) are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-l volume (/<=/55-bar) provides the gas to accelerate a 25.4-mm-diam piston in a 1-m-long pump tube; a burst disk or a fast valve initiates the acceleration process in the first stage.more » As the piston travels the length of the pump tube, the downstream gas (initially at <1 bar) is compressed (to pressures up to 2600 bar) and thus is driven to high temperature (approx.5000 K). This provides the driving force for acceleration of a 4-mm pellet in a 1-m-long gun barrel. In preliminary tests using helium as the driver in both stages, 35-mg plastic pellets have been accelerated to speeds as high as 3.8 km/s. Projectiles composed of hydrogen ice will have a mass in the range from 5 to 20 mg (/rho/ approx. 0.087, 0.20, and 0.32 g/cm/sup 3/ for frozen hydrogen isotopes). However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of approx.3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications. 25 refs., 6 figs., 1 tab.« less

Fracto-mechanoluminescent light emission of EuD4TEA-PDMS composites subjected to high strain-rate compressive loading

NASA Astrophysics Data System (ADS)

Ryu, Donghyeon; Castaño, Nicolas; Bhakta, Raj; Kimberley, Jamie

2017-08-01

The objective of this study is to understand light emission characteristics of fracto-mechanoluminescent (FML) europium tetrakis(dibenzoylmethide)-triethylammonium (EuD4TEA) crystals under high strain-rate compressive loading. As a sensing material that can play a pivotal role for the self-powered impact sensor technology, it is important to understand transformative light emission characteristics of the FML EuD4TEA crystals under high strain-rate compressive loading. First, EuD4TEA crystals were synthesized and embedded into polydimethylsiloxane (PDMS) elastomer to fabricate EuD4TEA-PDMS composite test specimens. Second, the prepared EuD4TEA-PDMS composites were tested using the modified Kolsky bar setup equipped with a high-speed camera. Third, FML light emission was captured to yield 12 bit grayscale video footage, which was processed to quantify the FML light emission. Finally, quantitative parameters were generated by taking into account pixel values and population of pixels of the 12 bit grayscale images to represent FML light intensity. The FML light intensity was correlated with high strain-rate compressive strain and strain rate to understand the FML light emission characteristics under high strain-rate compressive loading that can result from impact occurrences.

R&D of a High-Performance DIRC Detector for a Future Electron-Ion Collider

NASA Astrophysics Data System (ADS)

Allison, Stacey Lee

An Electron-Ion Collider (EIC) is proposed as the next big scientific facility to be built in the United States, costing over $1 billion in design and construction. Each detector concept for the electron/ion beam interaction point is integrated into a large solenoidal magnet. The necessity for excellent hadronic particle identification (pion/kaon/proton) in the barrel region of the solenoid has pushed research and development (R&D) towards a new, high-performance Detection of Internally Reflected Cherenkov light (DIRC) detector design. The passage of a high energy charged particle through a fused silica bar of the DIRC generates optical Cherenkov radiation. A large fraction of this light propagates by total internal reflection to the end of the bar, where the photon trajectories expand in a large volume before reaching a highly segmented photo-detector array. The spatial and temporal distribution of the Cherenkov light at the photo-detector array allows one to reconstruct the angle of emission of the light relative to the incident charged particle track. In order to reach the desired performance of 3sigma pi/K separation at 6 GeV/c particle momentum a new 3-layer spherical lens focusing optic with a lanthanum crown glass central layer was designed to have a nearly flat focal plane. In order to validate the EIC DIRC simulation package, a synergistic test beam campaign was carried out in 2015 at the CERN PS with the PANDA Barrel DIRC group using a prototype DIRC detector. Along with the analysis of the CERN test beam data, measurements of the focal plane of the 3-layer lens were performed using a custom-built laser setup at Old Dominion University. Radiation hardness of the lanthanum crown glass was tested using a 160 keV X-ray source and a monochromator at the Catholic University of America. Results of these test-bench experiments and the analysis of the 2015 CERN test beam data are presented here.

R&D of a high-performance DIRC detector for a future electron-ion collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allison, Staceu L.

An Electron-Ion Collider (EIC) is proposed as the next big scientific facility to be built in the United States, costing over $1 billion in design and construction. Each detector concept for the electron/ion beam interaction point is integrated into a large solenoidal magnet. The necessity for excellent hadronic particle identification (pion/kaon/proton) in the barrel region of the solenoid has pushed research and development (R&D) towards a new, high-performance Detection of Internally Reflected Cherenkov light (DIRC) detector design. The passage of a high energy charged particle through a fused silica bar of the DIRC generates optical Cherenkov radiation. A large fractionmore » of this light propagates by total internal reflection to the end of the bar, where the photon trajectories expand in a large volume before reaching a highly segmented photo-detector array. The spatial and temporal distribution of the Cherenkov light at the photo-detector array allows one to reconstruct the angle of emission of the light relative to the incident charged particle track. In order to reach the desired performance of 3sigma pi/K separation at 6 GeV/c particle momentum a new 3-layer spherical lens focusing optic with a lanthanum crown glass central layer was designed to have a nearly at focal plane. In order to validate the EIC DIRC simulation package, a synergistic test beam campaign was carried out in 2015 at the CERN PS with the PANDA Barrel DIRC group using a prototype DIRC detector. Along with the analysis of the CERN test beam data, measurements of the focal plane of the 3-layer lens were performed using a custom-built laser setup at Old Dominion University. Radiation hardness of the lanthanum crown glass was tested using a 160 keV X-ray source and a monochromator at the Catholic University of America. Results of these test-bench experiments and the analysis of the 2015 CERN test beam data are presented here.« less

Cobalt–iron nano catalysts supported on TiO{sub 2}–SiO{sub 2}: Characterization and catalytic performance in Fischer–Tropsch synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feyzi, Mostafa, E-mail: Dalahoo2011@yahoo.com; Yaghobi, Nakisa; Eslamimanesh, Vahid

2015-12-15

Graphical abstract: The Co–Fe/TiO{sub 2}–SiO{sub 2} catalysts were prepared. The prepared catalysts were tested for light olefins and C{sub 5}–C{sub 12} production. The best operational conditions are 250 °C, H{sub 2}/CO = 1/1 under 5 bar pressure. - Highlights: • The TiO{sub 2}–SiO{sub 2} supported cobalt–iron catalysts were prepared via sol–gel method. • The best operational conditions were 250 °C, GHSV = 2000 h{sup −1}, H{sub 2}/CO = 1/1 and 5 bar. • The (Co/Fe)/TiO{sub 2}–SiO{sub 2} is efficient catalyst for light olefins and C{sub 5}–C{sub 12} production. - Abstract: A series of Co–Fe catalysts supported on TiO{sub 2}–SiO{sub 2}more » were prepared by the sol–gel method. This research investigated the effects of (Co/Fe) wt.%, the solution pH, different Co/Fe molar ratio, calcination conditions and different promoters on the catalytic performance of cobalt–iron catalysts for the Fisher–Tropsch synthesis (FTS). It was found that the catalyst containing 35 wt.% (Co–Fe)/TiO{sub 2}–SiO{sub 2} (Co/Fe molar ratio is 80/20) promoted with 1.5 wt.% Cu and calcined in air atmosphere at 600 °C for 7 h with a heating rate of 3 °C min{sup −1} is an optimal nano catalyst for converting synthesis gas to light olefins and C{sub 5}–C{sub 12} hydrocarbons. The effects of operational conditions such as the H{sub 2}/CO ratio, gas hourly space velocity (GHSV), different reaction temperature, and reaction pressure were investigated. The results showed that the best operational conditions for optimal nano catalyst are 250 °C, GHSV = 2000 h{sup −1}, H{sub 2}/CO molar ratio 1/1 under 5 bar total pressure. Catalysts and precursors were characterized by, X-ray diffraction (XRD), scanning electron microcopy (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), temperature program reduction (TPR) and N{sub 2} adsorption–desorption measurements.« less

Meteor showers in review

NASA Astrophysics Data System (ADS)

Jenniskens, Peter

2017-09-01

Recent work on meteor showers is reviewed. New data is presented on the long duration showers that wander in sun-centered ecliptic coordinates. Since the early days of meteor photography, much progress has been made in mapping visual meteor showers, using low-light video cameras instead. Now, some 820,000 meteoroid orbits have been measured by four orbit surveys during 2007-2015. Mapped in sun-centered ecliptic coordinates in 5° intervals of solar longitude, the data show a number of long duration (>15 days) meteor showers that have drifting radiants and speeds with solar longitude. 18 showers emerge from the antihelion source and follow a drift pattern towards high ecliptic latitudes. 27 Halley-type showers in the apex source move mostly towards lower ecliptic longitudes, but those at high ecliptic latitudes move backwards. Also, 5 low-speed showers appear between the toroidal ring and the apex source, moving towards the antihelion source. Most other showers do not last long, or do not move much in sun-centered ecliptic coordinates. The surveys also detected episodic showers, which mostly document the early stages of meteoroid stream formation. New data on the sporadic background have shed light on the dynamical evolution of the zodiacal cloud.

Modeling some two-dimensional relativistic phenomena using an educational interactive graphics software

NASA Astrophysics Data System (ADS)

Sastry, G. P.; Ravuri, Tushar R.

1990-11-01

This paper describes several relativistic phenomena in two spatial dimensions that can be modeled using the collision program of Spacetime Software. These include the familiar aberration, the Doppler effect, the headlight effect, and the invariance of the speed of light in vacuum, in addition to the rather unfamiliar effects like the dragging of light in a moving medium, reflection at moving mirrors, Wigner rotation of noncommuting boosts, and relativistic rotation of shrinking and expanding rods. All these phenomena are exhibited by tracings of composite computer printouts of the collision movie. It is concluded that an interactive educational graphics software with pleasing visuals can have considerable investigative power packed within it.

When superfluids are a drag

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, David C

2008-01-01

The article considers the dramatic phenomenon of seemingly frictionless flow of slow-moving superfluids. Specifically the question of whether an object in a superfluid flow experiences any drag force is addressed. A brief account is given of the history of this problem and it is argued that recent advances in ultracold atomic physics can shed much new light on this problem. The article presents the commonly held notion that sufficiently slow-moving superfluids can flow without drag and also discusses research suggesting that scattering quantum fluctuations might cause drag in a superfluid moving at any speed.

The Use of Pristine and Intercalated Graphite Fiber Composites as Buss Bars in Lead-Acid Batteries

NASA Technical Reports Server (NTRS)

Opaluch, Amanda M.

2004-01-01

This study was conducted as a part of the Firefly Energy Space Act Agreement project to investigate the possible use of composite materials in lead acid batteries. Specifically, it examined the use of intercalated graphite composites as buss bars. Currently, buss bars of these batteries are made of lead, a material that is problematic for several reasons. Over time, the lead is subject to both corrosion at the positive plate and sulfation at the negative plate, resulting in decreased battery life. In addition, the weight and size of the lead buss bars make for a heavy and cumbersome battery that is undesirable. Functionality and practicality of lead buss bars is adequate at best; consequently, investigation of more efficient composite materials would be advantageous. Practically speaking, graphite composites have a low density that is nearly one fourth that of its lead counterpart. A battery made of less dense materials would be more attractive to the consumer and the producer because it would be light and convenient. More importantly, low weight would be especially beneficial because it would result in greater overall power density of the battery. In addition to power density, use of graphite composite materials can also increase the life of the battery. From a functional standpoint, corrosion and sulfation at the positive and negative plates are major obstacles when considering how to extend battery life. Neither of these reactions are a factor when graphite composites replace lead parts because graphite is chemically non-reactive with the electrolyte within the battery. Without the problem of corrosion or sulfation, battery life expectancy can be almost doubled. The replacement of lead battery parts with composite materials is also more environmentally favorable because of easy disposal of organic materials. For this study, both pristine and bromine intercalated single-ply graphite fiber composites were created. The composites were fabricated in such a way as to facilitate their use in a 3" x 1/2" buss bar test cell. The prime objective of this investigation was to examine the effectiveness of a variety of graphite composite materials to act as buss bars and carry the current to and from the positive and negative battery plates. This energy transfer can be maximized by use of materials with high conductivity to minimize the buss resistance. Electrical conductivity of composites was measured using both a contactless eddy current probe and a four point measurement. In addition, the stability of these materials at battery-use conditions was characterized.

Light propagation in gas-filled kagomé hollow core photonic crystal fibres

NASA Astrophysics Data System (ADS)

Rodrigues, Sílvia M. G.; Facão, Margarida; Ferreira, Mário F. S.

2018-04-01

We study the propagation of light in kagomé hollow core photonic crystal fibres (HC-PCFs) filled with three different noble gases, namely, helium, xenon and argon. Various properties, including the guided modes, the group-velocity dispersion, and the nonlinear parameter were determined. The zero dispersion wavelength and the nonlinear parameter vary with the gas pressure which may be used to tune the generation of new frequencies using the same pump laser and the same fibre. In the case of the kagomé HC-PCF filled with xenon, the zero dispersion wavelength shifts from 693 to 1973 nm when the pressure is increased from 1 to 150bar, while the effective Kerr nonlinearity becomes comparable to that of silica. We have simulated the propagation of femtosecond pulses launched at 790 nm in order to study the generation of supercontinuum and UV light in kagomé HC-PCFs filled with the noble gases.

Does platelet count in platelet-rich plasma influence slope, maximal amplitude and lag phase in healthy individuals? Results of light transmission aggregometry.

PubMed

Chandrashekar, Vani

2015-01-01

Light transmission aggregometry lacks in standardisation and normal reference values are not widely available. The aims of our study were to establish reference ranges for aggregation, slope and lag phase in healthy controls with platelet counts between 150 and 450 × 10(9)/l in platelet-rich plasma (PRP) as well as evaluate the influence of platelet count. Ninety-nine subjects were evaluated with four agonists and divided into two groups based on platelet count and the groups were compared by Student's t-test. There was no difference between the means of the two groups for amplitude and slope barring the lag phase for collagen. Platelet counts between 150 and 450 × 10(9)/l have no effects on light transmission aggregometry and hence adjustment of platelet count is not necessary.

Prospects of discovering stable double-heavy tetraquarks at a Tera-Z factory

NASA Astrophysics Data System (ADS)

Ali, Ahmed; Parkhomenko, Alexander Ya.; Qin, Qin; Wang, Wei

2018-07-01

Motivated by a number of theoretical considerations, predicting the deeply bound double-heavy tetraquarks T[ u bar d bar ]{ bb }, T[ u bar s bar ]{ bb } and T[ d bar s bar ]{ bb }, we explore the potential of their discovery at Tera-Z factories. Using the process Z → b b bar b b bar , we calculate, employing the Monte Carlo generators MadGraph5_aMC@NLO and Pythia6, the phase space configuration in which the bb pair is likely to fragment as a diquark. In a jet-cone, defined by an invariant mass interval mbb < M T[ q bar qbar‧ ]{ bb } + ΔM, the sought-after tetraquarks T[ q bar qbar‧ ]{ bb } as well as the double-bottom baryons, Ξbb0,-, and Ωbb- , can be produced. Using the heavy quark-diquark symmetry, we estimate B (Z → T[ u bar d bar ]{ bb } + b bar b bar) = (1.2-0.3+1.0) ×10-6, and about a half of this for the T[ u bar s bar ]{ bb } and T[ d bar s bar ]{ bb } . We also present an estimate of their lifetimes using the heavy quark expansion, yielding τ (T[ q bar qbar‧ ]{ bb }) ≃ 800 fs. Measuring the tetraquark masses would require decays, such as T[ u bar d bar ]{ bb } - →B-D-π+, T [ u bar d bar ]{ bb } - → J / ψK‾0B-, T[ u bar d bar ]{ bb } - → J / ψK-B‾0, T[ u bar s bar ]{ bb } - → Ξbc0 Σ-, and T[ d bar s bar ]{ bb } 0 → Ξbc0 Σbar0, with subsequent decay chains in exclusive non-leptonic final states. We estimate a couple of the decay widths and find that the product branching ratios do not exceed 10-5. Hence, a good fraction of these modes will be required for a discovery of T[ q bar qbar‧ ]{ bb } at a Tera-Z factory.

Integration of organic LEDs with inorganic LEDs for a hybrid lighting system

NASA Astrophysics Data System (ADS)

Kong, H. J.; Park, J. W.; Kim, Y. M.

2013-01-01

We demonstrate that a surface-emitting hybrid light source can be realized by a combination of organic and inorganic light-emitting devices (LEDs). To this end, a blue inorganic LED bar is deployed at one side of a transparent light guide plate (LGP), and a yellow organic LED (OLED) is in contact with the rear surface of the LGP. In such a configuration, it is found that the overall luminance is almost equivalent to the sum of the luminances measured from each light source, and the overall luminance uniformity is determined mainly by the luminance uniformity of the OLED panel at high luminances. We have achieved a white color showing the Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (x = 0.34, y = 0.33), the power efficiency of 9.3 lm/W, the luminance uniformity of 63% at the luminance of 3100 cd m-2, the color rendering index as high as 89.3, and the correlated color temperature finely tunable within the range between 3000 and 8000 K. Such a system facilitates color tuning by adjusting their luminous intensities and hence the implementation of the emotional lighting system.

Breakthrough bargaining.

PubMed

Kolb, D M; Williams, J

2001-02-01

Unspoken, subtle parts of a bargaining process--also known as the shadow negotiation--can set the tone for a successful negotiation. Deborah Kolb and Judith Williams, whose book The Shadow Negotiation was the starting point for this article, say there are three strategies businesspeople can use to guide these hidden interactions. Power moves are used when two negotiating parties hold unequal power--for instance, subordinates and bosses; new and existing employees; and people of different races, ages, or genders. These strategies, such as casting the status quo in an unfavorable light, can help parties realize that they must negotiate: they will be better off if they do and worse off if they don't. Process moves affect how negotiation issues are received by both sides in the process, even though they do not address substantive issues. Working outside of the actual bargaining process, one party can suggest ideas or marshal support that can shape the agenda and influence how others view the negotiation. Appreciative moves alter the tone or atmosphere so that a more collaborative exchange is possible. They shift the dynamics of the shadow negotiation away from the adversarial--helping parties to save face--and thus build trust and encourage dialogue. These strategic moves don't guarantee that all bargainers will walk away winners, but they help to get stalled negotiations moving--out of the dark of unspoken power plays and into the light of true dialogue.

An intervention to reduce sitting and increase light-intensity physical activity at work: Design and rationale of the 'Stand & Move at Work' group randomized trial.

PubMed

Buman, Matthew P; Mullane, Sarah L; Toledo, Meynard J; Rydell, Sarah A; Gaesser, Glenn A; Crespo, Noe C; Hannan, Peter; Feltes, Linda; Vuong, Brenna; Pereira, Mark A

2017-02-01

American workers spend 70-80% of their time at work being sedentary. Traditional approaches to increase moderate-vigorous physical activity (MVPA) may be perceived to be harmful to productivity. Approaches that target reductions in sedentary behavior and/or increases in standing or light-intensity physical activity [LPA] may not interfere with productivity and may be more feasible to achieve through small changes accumulated throughout the workday METHODS/DESIGN: This group randomized trial (i.e., cluster randomized trial) will test the relative efficacy of two sedentary behavior focused interventions in 24 worksites across two states (N=720 workers). The MOVE+ intervention is a multilevel individual, social, environmental, and organizational intervention targeting increases in light-intensity physical activity in the workplace. The STAND+ intervention is the MOVE+ intervention with the addition of the installation and use of sit-stand workstations to reduce sedentary behavior and enhance light-intensity physical activity opportunities. Our primary outcome will be objectively-measured changes in sedentary behavior and light-intensity physical activity over 12months, with additional process measures at 3months and longer-term sustainability outcomes at 24months. Our secondary outcomes will be a clustered cardiometabolic risk score (comprised of fasting glucose, insulin, triglycerides, HDL-cholesterol, and blood pressure), workplace productivity, and job satisfaction DISCUSSION: This study will determine the efficacy of a multi-level workplace intervention (including the use of a sit-stand workstation) to reduce sedentary behavior and increase LPA and concomitant impact on cardiometabolic health, workplace productivity, and satisfaction. ClinicalTrials.gov Identifier: NCT02566317 (date of registration: 10/1/2015). Copyright © 2016 Elsevier Inc. All rights reserved.

Processing Research on Chemically Vapor Deposited Silicon Nitride

DTIC Science & Technology

1981-12-01

forming silicon carbide to reduce free silicon content. (b) Boron and aluminum were selected as two single-valence elements with small atomic radii which...obtained in cold wall (CW-3) runs were sliced into small flexure bars (19.1x3.2xt(mm) where t = thickness) if they appeared to be of suitable quality...discussed later. Addition of borcn trichloride in small amounts (Run 8) caused Formation of a light blue translucent deposit which contained at least one

U.S. Army Concept of Operations and Standard Operating Procedure for Acquisition Program Managers Using Item Unique Identification

DTIC Science & Technology

2017-09-01

Figure 58. Click on run ................................................................................................61 Figure 59. Top view of...engines, helicopter rotors, and turbine blades , and so forth Creating Marks Readable with a Scanner 4.  Simple techniques to follow:  Make the light...spreadsheet with data Figure 58. Click on Menu bar and find “View” then click on “Macros.” Click on run Figure 59. 62 Top view of xml spreadsheet

Evolutionary Artificial Neural Network Weight Tuning to Optimize Decision Making for an Abstract Game

DTIC Science & Technology

2010-03-01

separate LoA heuristic. If any of the examined heuristics produced competitive player , then the final measurement was a success . Barring that, a...if offline training actually results in a successful player . Whereas offline learning plays many games and then trains as many networks as desired...a competitive Lines of Action player , shedding light on the difficulty of developing a neural network to model such a large and complex solution

CHANGES IN THE CRAB PULSAR

NASA Technical Reports Server (NTRS)

2002-01-01

Scientists are learning more about how pulsars work by studying a series of Hubble Space Telescope images of the heart of the Crab Nebula. The images, taken over a period of several months, show that the Crab is a far more dynamic object than previously understood. At the center of the nebula lies the Crab Pulsar. The pulsar is a tiny object by astronomical standards -- only about six miles across -- but has a mass greater than that of the Sun and rotates at a rate of 30 times a second. As the pulsar spins its intense magnetic field whips around, acting like a sling shot, accelerating subatomic particles and sending them hurtling them into space at close to the speed of light. The tiny pulsar and its wind are the powerhouse for the entire Crab Nebula, which is 10 light-years across -- a feat comparable to an object the size of a hydrogen atom illuminating a volume of space a kilometer across. The three pictures shown here, taken from the series of Hubble images, show dramatic changes in the appearance of the central regions of the nebula. These include wisp-like structures that move outward away from the pulsar at half the speed of light, as well as a mysterious 'halo' which remains stationary, but grows brighter then fainter over time. Also seen are the effects of two polar jets that move out along the rotation axis of the pulsar. The most dynamic feature seen -- a small knot that 'dances around' so much that astronomers have been calling it a 'sprite' -- is actually a shock front (where fast-moving material runs into slower-moving material)in one of these polar jets. The telescope captured the images with the Wide Field and Planetary Camera 2 using a filter that passes light of wavelength around 550 nanometers, near the middle of the visible part of the spectrum. The Crab Nebula is located 7,000 light-years away in the constellation Taurus. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

Caspase Inhibition with XIAP as an Adjunct to AAV Vector Gene-Replacement Therapy: Improving Efficacy and Prolonging the Treatment Window

PubMed Central

Yao, Jingyu; Jia, Lin; Khan, Naheed; Zheng, Qiong-Duan; Moncrief, Ashley; Hauswirth, William W.; Thompson, Debra A.; Zacks, David N.

2012-01-01

Purpose AAV-mediated gene therapy in the rd10 mouse, with retinal degeneration caused by mutation in the rod cyclic guanosine monophosphate phosphodiesterase β-subunit (PDEβ) gene, produces significant, but transient, rescue of photoreceptor structure and function. This study evaluates the ability of AAV-mediated delivery of X-linked inhibitor of apoptosis (XIAP) to enhance and prolong the efficacy of PDEβ gene-replacement therapy. Methods Rd10 mice were bred and housed in darkness. Two groups of animals were generated: Group 1 received sub-retinal AAV5-XIAP or AAV5-GFP at postnatal age (P) 4 or 21 days; Group 2 received sub-retinal AAV5-XIAP plus AAV5- PDEβ, AAV5-GFP plus AAV5- PDEβ, or AAV- PDEβ alone at age P4 or P21. Animals were maintained for an additional 4 weeks in darkness before being moved to a cyclic-light environment. A subset of animals from Group 1 received a second sub-retinal injection of AAV8-733-PDEβ two weeks after being moved to the light. Histology, immunohistochemistry, Western blots, and electroretinograms were performed at different times after moving to the light. Results Injection of AAV5-XIAP alone at P4 and 21 resulted in significant slowing of light-induced retinal degeneration, as measured by outer nuclear thickness and cell counts, but did not result in improved outer segment structure and rhodopsin localization. In contrast, co-injection of AAV5-XIAP and AAV5-PDEβ resulted in increased levels of rescue and decreased rates of retinal degeneration compared to treatment with AAV5-PDEβ alone. Mice treated with AAV5-XIAP at P4, but not P21, remained responsive to subsequent rescue by AAV8-733-PDEβ when injected two weeks after moving to a light-cycling environment. Conclusions Adjunctive treatment with the anti-apoptotic gene XIAP confers additive protective effect to gene-replacement therapy with AAV5-PDEβ in the rd10 mouse. In addition, AAV5-XIAP, when given early, can increase the age at which gene-replacement therapy remains effective, thus effectively prolonging the window of opportunity for therapeutic intervention. PMID:22615940

Associations Between Rate of Force Development Metrics and Throwing Velocity in Elite Team Handball Players: a Short Research Report

PubMed Central

Marques, Mário C.; Saavedra, Francisco J.; Abrantes, Catarina; Aidar, Felipe J.

2011-01-01

Performance assessment has become an invaluable component of monitoring participant’s development in distinct sports, yet limited and contradictory data are available in trained subjects. The purpose of this study was to examine the relationship between ball throwing velocity during a 3-step running throw in elite team handball players and selected measures of rate of force development like force, power, velocity, and bar displacement during a concentric only bench press exercise in elite male handball players. Fitteen elite senior male team handball players volunteered to participate. Each volunteer had power and bar velocity measured during a concentric only bench press test with 25, 35, and 45 kg as well as having one-repetition maximum strength determined. Ball throwing velocity was evaluated with a standard 3-step running throw using a radar gun. The results of this study indicated significant associations between ball velocity and time at maximum rate of force development (0, 66; p<0.05) and rate of force development at peak force (0,56; p<0.05) only with 25kg load. The current research indicated that ball velocity was only median associated with maximum rate of force development with light loads. A training regimen designed to improve ball-throwing velocity in elite male team handball players should emphasize bench press movement using light loads. PMID:23487363

Hybrid reflection type metasurface of nano-antennas designed for optical needle field generation

NASA Astrophysics Data System (ADS)

Wang, Shiyi; Zhan, Qiwen

2015-03-01

We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid optical antennas for comprehensive spatial engineering the properties of optical fields. Its capability is illustrated with an example to create a radially polarized vectorial beam for optical needle field generation. Functioning as local quarter-wave-plates (QWP), the MIM metasurface is designed to convert circularly polarized incident into local linear polarization to create an overall radial polarization with corresponding binary phases and desired normalized amplitude modulation ranged from 0.07 to 1. To obtain enough degrees of freedom, the optical-antenna layer comprises periodic arrangements of double metallic nano-bars with perpendicular placement and single nano-bars respectively for different amplitude modulation requirements. Both of the antennas enable to introduce π/2 retardation while reaching the desired modulation range both for phase and amplitude. Through adjusting the antennas' geometry and array carefully, we shift the gap-surface plasmon resonances facilitated by optical antennas to realize the manipulation of vectorial properties. Designed at 1064 nm wavelength, the particularly generated vectorial light output can be further tightly focused by a high numerical aperture objective to obtain longitudinally polarized flat-top focal field. The so-called optical needle field is a promising candidate for novel applications that transcend disciplinary boundaries. The proposed metasurface establishes a new class of compact optical components based on nano-scale structures, leading to compound functions for vectorial light generation.

Associations between rate of force development metrics and throwing velocity in elite team handball players: a short research report.

PubMed

Marques, Mário C; Saavedra, Francisco J; Abrantes, Catarina; Aidar, Felipe J

2011-09-01

Performance assessment has become an invaluable component of monitoring participant's development in distinct sports, yet limited and contradictory data are available in trained subjects. The purpose of this study was to examine the relationship between ball throwing velocity during a 3-step running throw in elite team handball players and selected measures of rate of force development like force, power, velocity, and bar displacement during a concentric only bench press exercise in elite male handball players. Fitteen elite senior male team handball players volunteered to participate. Each volunteer had power and bar velocity measured during a concentric only bench press test with 25, 35, and 45 kg as well as having one-repetition maximum strength determined. Ball throwing velocity was evaluated with a standard 3-step running throw using a radar gun. The results of this study indicated significant associations between ball velocity and time at maximum rate of force development (0, 66; p<0.05) and rate of force development at peak force (0,56; p<0.05) only with 25kg load. The current research indicated that ball velocity was only median associated with maximum rate of force development with light loads. A training regimen designed to improve ball-throwing velocity in elite male team handball players should emphasize bench press movement using light loads.

Photo-triggering and secondary electron produced ionization in electric discharge ArF* excimer lasers

NASA Astrophysics Data System (ADS)

Xiong, Zhongmin; Kushner, Mark J.

2011-10-01

Electric discharge excimer lasers are sustained in multi-atmosphere attaching gas mixtures that are typically preionized to enable a reproducible, uniform glow, which maximizes optical quality and gain. This preionization is often accomplished using UV light produced by a corona discharge within the plasma cavity. To quantify the relationship between corona discharge properties and those of the laser discharge, the triggering of electron avalanche by preionizing UV light in an electric discharge-pumped ArF* excimer laser was numerically investigated using a two-dimensional model. The preionizing UV fluxes were generated by a corona-bar discharge driven by the same voltage pulse as the main discharge sustained in a multi-atmospheric Ne/Ar/Xe/F2 gas mixture. The resulting peak photo-electron density in the inter-electrode spacing is around 108 cm-3, and its distribution is biased toward the UV source. The preionization density increases with increasing dielectric constant and capacitance of the corona bar. The symmetry and uniformity of the discharge are, however, improved significantly once the main avalanche develops. In addition to bulk electron impact ionization, the ionization generated by sheath accelerated secondary electrons was found to be important in sustaining the discharge current at experimentally observed values. At peak current, the magnitude of the ionization by sheath accelerated electrons is comparable to that from bulk electron impact in the vicinity of the cathode.

On measurement of the isotropy of the speed of light

DOE PAGES

Wojtsekhowski, B.

2014-10-22

Three experimental concepts investigating possible anisotropy of the speed of light are presented. They are based on i) beam deflection in a 180° magnetic arc, ii) narrow resonance production in an electron-positron collider, and iii) the ratio of magnetic moments of an electron and a positron moving in opposite directions.

Circadian Rhythm of Pyrocystis fusiformis

NASA Astrophysics Data System (ADS)

Weishaar, B.

2016-12-01

For the Academy of Science St. Louis Science Fair, I tested how different photoperiods affect the morphology of Pyrocystis fusiformis with respect to the placement and formation of the chloroplasts. I set up four different rooms to observe the effect the different times in the photoperiod on location of chloroplasts in the cell. At 3:00pm, one room has been in the dark for 12 hours, one for 6 hours, one had been in the light phase for 12 hours and the fourth in the light phase for 6 hours. P fusiformis samples were obtained from each room, observed, photographed at X100 power, and categorized as being a 1, 2, 3, or 4 depending on the position of the chloroplasts. The samples in the different rooms were observed once a week for two weeks, then the samples were rotated to see if P. fusiformis would synchronize the same to the new photoperiod. It was observed that the cells changed morphological stages in the circadian cycle, the chloroplasts moved further away from the nucleus when exposed to light and moved closer to the nucleus when experiencing no light.

Twin imaging phenomenon of integral imaging.

PubMed

Hu, Juanmei; Lou, Yimin; Wu, Fengmin; Chen, Aixi

2018-05-14

The imaging principles and phenomena of integral imaging technique have been studied in detail using geometrical optics, wave optics, or light filed theory. However, most of the conclusions are only suit for the integral imaging systems using diffused illumination. In this work, a kind of twin imaging phenomenon and mechanism has been observed in a non-diffused illumination reflective integral imaging system. Interactive twin images including a real and a virtual 3D image of one object can be activated in the system. The imaging phenomenon is similar to the conjugate imaging effect of hologram, but it base on the refraction and reflection instead of diffraction. The imaging characteristics and mechanisms different from traditional integral imaging are deduced analytically. Thin film integral imaging systems with 80μm thickness have also been made to verify the imaging phenomenon. Vivid lighting interactive twin 3D images have been realized using a light-emitting diode (LED) light source. When the LED is moving, the twin 3D images are moving synchronously. This interesting phenomenon shows a good application prospect in interactive 3D display, argument reality, and security authentication.

Measuring Gravitation Using Polarization Spectroscopy

NASA Technical Reports Server (NTRS)

Matsko, Andrey; Yu, Nan; Maleki, Lute

2004-01-01

A proposed method of measuring gravitational acceleration would involve the application of polarization spectroscopy to an ultracold, vertically moving cloud of atoms (an atomic fountain). A related proposed method involving measurements of absorption of light pulses like those used in conventional atomic interferometry would yield an estimate of the number of atoms participating in the interferometric interaction. The basis of the first-mentioned proposed method is that the rotation of polarization of light is affected by the acceleration of atoms along the path of propagation of the light. The rotation of polarization is associated with a phase shift: When an atom moving in a laboratory reference interacts with an electromagnetic wave, the energy levels of the atom are Doppler-shifted, relative to where they would be if the atom were stationary. The Doppler shift gives rise to changes in the detuning of the light from the corresponding atomic transitions. This detuning, in turn, causes the electromagnetic wave to undergo a phase shift that can be measured by conventional means. One would infer the gravitational acceleration and/or the gradient of the gravitational acceleration from the phase measurements.

Star formation quenching in green valley galaxies at 0.5 ≲ z ≲ 1.0 and constraints with galaxy morphologies

NASA Astrophysics Data System (ADS)

Nogueira-Cavalcante, J. P.; Gonçalves, T. S.; Menéndez-Delmestre, K.; Sheth, K.

2018-01-01

We calculate the star formation quenching time-scales in green valley galaxies at intermediate redshifts (z ∼ 0.5-1) using stacked zCOSMOS spectra of different galaxy morphological types: spheroidal, disc-like, irregular and merger, dividing disc-like galaxies further into unbarred, weakly barred and strongly barred, assuming a simple exponentially decaying star formation history model and based on the H δ absorption feature and the 4000 Å break. We find that different morphological types present different star formation quenching time-scales, reinforcing the idea that the galaxy morphology is strongly correlated with the physical processes responsible for quenching star formation. Our quantification of the star formation quenching time-scale indicates that discs have typical time-scales 60 per cent to five times longer than that of galaxies presenting spheroidal, irregular or merger morphologies. Barred galaxies, in particular, present the slowest transition time-scales through the green valley. This suggests that although secular evolution may ultimately lead to gas exhaustion in the host galaxy via bar-induced gas inflows that trigger star formation activity, secular agents are not major contributors in the rapid quenching of galaxies at these redshifts. Galaxy interaction, associated with the elliptical, irregular and merger morphologies, contributes, to a more significant degree, to the fast transition through the green valley at these redshifts. In light of previous works suggesting that both secular and merger processes are responsible for the star formation quenching at low redshifts, our results provide an explanation to the recent findings that star formation quenching happened at a faster pace at z ∼ 0.8.

The descriptive epidemiology of local restaurant smoking regulations in Massachusetts: an analysis of the protection of restaurant customers and workers

PubMed Central

Skeer, M; Siegel, M

2003-01-01

Objectives: To describe the range of restaurant smoking regulations in the 351 cities and towns in Massachusetts, and to analyse the level of protection from secondhand smoke exposure guaranteed by these regulations. Design: We obtained the local restaurant smoking regulations for each town, analysing them in terms of the protection of restaurant workers, bar workers, and adult and youth restaurant customers. Main outcome measure: The percentage of restaurant patrons and workers and bar workers who are protected from secondhand smoke exposure by the current smoking regulations in Massachusetts. Results: As of June 2002, 225 towns had local restaurant smoking regulations. Of these, 69 (30.7%) do not allow smoking in restaurants, 10 (4.4%) restrict smoking to adult only restaurants, 64 (28.4%) restrict smoking to enclosed, separately ventilated areas, and 82 (36.4%) restrict smoking to areas that need not be enclosed and separately ventilated. Of the 174 towns that, at a minimum, restrict smoking to bar areas or separately ventilated areas, 35 (20.1%) allow variances. Overall, 60 towns, covering only 17.7% of the population, completely ban smoking in restaurants. As a result, 81.3% of adult restaurant customers, 81.2% of youth customers, 82.3% of restaurant workers, and 87.0% of bar workers are not guaranteed protection from secondhand smoke in restaurants. Conclusions: Despite the widespread adoption of local restaurant smoking regulations in Massachusetts, the majority of restaurant customers and workers remain unprotected from secondhand smoke exposure. In light of this, public health practitioners must stop compromising the protection of customers and workers from secondhand smoke exposure in restaurants. PMID:12773735

Fluvial bar dynamics in large meandering rivers with different sediment supply in the Amazon River basin

NASA Astrophysics Data System (ADS)

Monegaglia, Federico; Zolezzi, Guido; Tubino, Marco; Henshaw, Alex

2017-04-01

Sediments in the large meandering rivers of the Amazon basin are known to be supplied by sources providing highly different magnitudes of sediment input and storage, ranging from the sediment-rich Andean region to the sediment-poor Central Trough. Recent observations have highlighted how such differences in sediment supply have an important, net effect on the rates of planform activity of meandering rivers in the basin, in terms of meander migration and frequency of cutoffs. In this work we quantify and discuss the effect of sediment supply on the organization of macroscale sediment bedforms on several large meandering rivers in the Amazon basin, and we link our findings with those regarding the rates of planform activity. Our analysis is conducted through the newly developed software PyRIS, which enables us to perform extensive multitemporal analysis of river morphodynamics from multispectral remotely sensed Landsat imagery in a fully automated fashion. We show that large rivers with low sediment supply tend to develop alternate bars that consistently migrate through long reaches, characterized at the same time by limited planform development. On the contrary, high sediment supply is associated with the development of point bars that are well-attached to the evolving meander bends and that follow temporal oscillations around the bend apexes, which in turn show rapid evlution towards complex meander shapes. Finally, rivers with intermediate rates of sediment supply develop rather steady point bars associated with slowly migrating, regular meanders. We finally discuss the results of the image analysis in the light of the properties of river planform metrics (like channel curvature and width) for the examined classes of river reaches with different sediment supply rates.

Surface tension mediated conversion of light to work

DOEpatents

Okawa, David; Pastine, Stefan J; Zettl, Alexander K; Frechet, Jean M. J

2014-12-02

Disclosed are a method and apparatus for converting light energy to mechanical energy by modification of surface tension on a supporting fluid. The apparatus comprises an object which may be formed as a composite object comprising a support matrix and a highly light absorptive material. The support matrix may comprise a silicon polymer. The highly light absorptive material may comprise vertically aligned carbon nanotubes (VANTs) embedded in the support matrix. The composite object is supported on a fluid. By exposing the highly light absorptive material to light, heat is generated, which changes the surface tension of the composite object, causing it to move physically within the fluid.

Optically controlled electrophoresis with a photoconductive substrate

NASA Astrophysics Data System (ADS)

Inami, Wataru; Nagashima, Taiki; Kawata, Yoshimasa

2018-05-01

A photoconductive substrate is used to perform electrophoresis. Light-induced micro-particle flow manipulation is demonstrated without using a fabricated flow channel. The path along which the particles were moved was formed by an illuminated light pattern on the substrate. Because the substrate conductivity and electric field distribution can be modified by light illumination, the forces acting on the particles can be controlled. This technique has potential applications as a high functionality analytical device.

Valve-sparing options in tetralogy of Fallot surgery.

PubMed

Bacha, Emile

2012-01-01

Given late outcomes of patients with tetralogy of Fallot repaired in the 1970s and 1980s, as well as a better understanding of the late deleterious effects of pulmonary regurgitation, there is a tendency toward preservation of the pulmonary valve function during primary repair of tetralogy of Fallot. The bar keeps moving downward, to include smaller and more dysmorphic pulmonary valves. This article reviews some useful indications and techniques for valve-sparing options, including intraoperative balloon dilation and cusp reconstruction using a patch. Just like other valve repair techniques, no one technique can be applied uniformly, and surgeons must master a wide armamentarium of techniques. Copyright © 2012 Elsevier Inc. All rights reserved.

Optical programmable Boolean logic unit.

PubMed

Chattopadhyay, Tanay

2011-11-10

Logic units are the building blocks of many important computational operations likes arithmetic, multiplexer-demultiplexer, radix conversion, parity checker cum generator, etc. Multifunctional logic operation is very much essential in this respect. Here a programmable Boolean logic unit is proposed that can perform 16 Boolean logical operations from a single optical input according to the programming input without changing the circuit design. This circuit has two outputs. One output is complementary to the other. Hence no loss of data can occur. The circuit is basically designed by a 2×2 polarization independent optical cross bar switch. Performance of the proposed circuit has been achieved by doing numerical simulations. The binary logical states (0,1) are represented by the absence of light (null) and presence of light, respectively.

Interactions between Channel Morphology and the Propagation of Coarse Sediment Augmentations Downstream from Dams

NASA Astrophysics Data System (ADS)

Gaeuman, D. A.; Dickenson, S.; Pyles, M.

2009-12-01

Gravel augmentations are being implemented in a number of streams where natural recruitment of gravel is impeded by dams. Uncertainties relevant to the management of gravel augmentations include the quantities of gravel needed to achieve habitat benefits at downstream locations and the temporal and spatial scales over which those benefits that will be realized. The solution to such questions depends to a large extent on how gravel slugs evolve as the material is transported downstream, i.e., whether the gravel translates downstream as a coherent wave or whether it tends to disperse. A number of recent studies conducted in laboratory flumes or by numerical simulation that gravels slugs tend to disperse rather than translate. However, these studies do not consider the influence of channel morphology on slug behavior. Initial monitoring results based from 2 California streams suggest that natural channel morphology suppresses slug dispersion because the gravel tends to accumulate in discrete deposition zones. Field mapping and about 200 tracer stones implanted with passive integrated transponder (PIT) tags show that gravel recruitment piles of about 80 tons each placed in Grass Valley Creek in 2007 and 2008 were deposited as 2 new bars immediately downstream. The more upstream of the 2 bars formed during the 2007 winter and spring flood season, whereas the more downstream bar did not appear until the following year. A sharp deposition front and an absence of tracers in the reaches downstream strongly suggest that none of the added gravel was transported downstream beyond the area of bar formation in either year. A relatively small proportion of the mobilized tracer particles (59%) were located following the 2007 flood season, probably due to deep burial in the newly deposited bar and to radio interference caused by the high concentration of tracers in a small area. The proportion of newly introduced or previously-located tracers that were relocated in 2009 was considerably higher (88%), suggesting that average burial depths decrease as the deposition front moves downstream. In addition, about one quarter of the tracers that were missing in 2008 were recovered in 2009, indicating that some of the particles buried during the first flood season were exhumed the following year. Changes in bed topography downstream from a gravel augmentation in the Trinity River provide additional evidence that the presence of discrete deposition zones in stream channels tends to suppress gravel dispersion. Repeat bathymetric surveys conducted in the Trinity River before and after placement of 1000 tons of gravel during a 2008 high-flow event show that a quantity of gravel equivalent to the augmentation volume was deposited on the first bar downstream from the augmentation point.

Using a Fuzzy Light Sensor to Improve the Efficiency of Solar Panels

NASA Astrophysics Data System (ADS)

Suryono; Suseno, Jatmiko Endro; Sulistiati, Ainie Khuriati Riza; Prahara, Tahan

2018-02-01

Solar panel efficiency can be increased by improving the quality of photovoltaic material, the effectiveness of electronic circuit, and the light source tracking model. This research is aimed at improving the quality of solar panels by tracking light source using a fuzzy logic sensor. A fuzzy light sensor property is obtained from two LDR (light dependent resistor) light sensors installed in parallel to each other and is given a light separator in between them. Both sensors are mounted on a solar panel. Sensor output is acquired using a 12 bit ADC from an ATSAM3XE microcontroller and is then sent to a computer using WIFI radio. A PID (Proportional-Integral-Derivative) control algorithm is used to manage the position of the solar panel in line with the input given by the fuzzy light sensor. This control mechanism works based on the margin of fuzzy membership from both sensors that is used to move a motor DC that in turn moves the solar panel. Experimental results show a characteristically symmetrical fuzzy membership of both sensors with a reflected correlation of R=0.9981 after gains from both sensors are arranged with a program. Upon being tested in the field, this system was capable of improving the performance of solar panels in gaining power compared to their original fixed position. The discrepancy was evident when the angle of incoming sunlight approached both 0° and 180°. Further calculations of data acquired by the fuzzy light sensor show increased solar panel power efficiency by up to 5.6%.

Light, genotype, and abscisic acid affect chloroplast positioning in guard cells of Arabidopsis thaliana leaves in distinct ways.

PubMed

Königer, Martina; Jessen, Brita; Yang, Rui; Sittler, Dorothea; Harris, Gary C

2010-09-01

The goal of this study was to investigate the effects of light intensity, genotype, and various chemical treatments on chloroplast movement in guard cells of Arabidopsis thaliana leaves. After treatment at various light intensities (dark, low, and high light), leaf discs were fixed with glutaraldehyde, and imaged using confocal laser microscopy. Each chloroplast was assigned a horizontal (close to pore, center, or epidermal side) and vertical (outer, middle, inner) position. White light had a distinct effect on chloroplast positioning, most notably under high light (HL) when chloroplasts on the upper leaf surface of wild-type (WT) moved from epidermal and center positions toward the pore. This was not the case for phot1-5/phot2-1 or phot2-1 plants, thus phototropins are essential for chloroplast positioning in guard cells. In npq1-2 mutants, fewer chloroplasts moved to the pore position under HL than in WT plants, indicating that white light can affect chloroplast positioning also in a zeaxanthin-dependent way. Cytochalasin B inhibited the movement of chloroplasts to the pore under HL, while oryzalin did not, supporting the idea that actin plays a role in the movement. The movement along actin cables is dependent on CHUP1 since chloroplast positioning in chup1 was significantly altered. Abscisic acid (ABA) caused most chloroplasts in WT and phot1-5/phot2-1 to be localized in the center, middle part of the guard cells irrespective of light treatment. This indicates that not only light but also water stress influences chloroplast positioning.

The mechanisms and boundary conditions of the Einstellung effect in chess: evidence from eye movements.

PubMed

Sheridan, Heather; Reingold, Eyal M

2013-01-01

In a wide range of problem-solving settings, the presence of a familiar solution can block the discovery of better solutions (i.e., the Einstellung effect). To investigate this effect, we monitored the eye movements of expert and novice chess players while they solved chess problems that contained a familiar move (i.e., the Einstellung move), as well as an optimal move that was located in a different region of the board. When the Einstellung move was an advantageous (but suboptimal) move, both the expert and novice chess players who chose the Einstellung move continued to look at this move throughout the trial, whereas the subset of expert players who chose the optimal move were able to gradually disengage their attention from the Einstellung move. However, when the Einstellung move was a blunder, all of the experts and the majority of the novices were able to avoid selecting the Einstellung move, and both the experts and novices gradually disengaged their attention from the Einstellung move. These findings shed light on the boundary conditions of the Einstellung effect, and provide convergent evidence for Bilalić, McLeod, & Gobet (2008)'s conclusion that the Einstellung effect operates by biasing attention towards problem features that are associated with the familiar solution rather than the optimal solution.

Development of a dual-ended readout detector with segmented crystal bars made using a subsurface laser engraving technique

NASA Astrophysics Data System (ADS)

Mohammadi, Akram; Yoshida, Eiji; Nishikido, Fumihiko; Nitta, Munetaka; Shimizu, Keiji; Sakai, Toshiaki; Yamaya, Taiga

2018-01-01

Depth of interaction (DOI) information is indispensable to improving the sensitivity and spatial resolution of positron emission tomography (PET) systems, especially for small field-of-view PET such as small animal PET and human brain PET. We have already developed a series of X’tal cube detectors for isotropic spatial resolution and we obtained the best isotropic resolution of 0.77 mm for detectors with six-sided readout. However, it is still challenging to apply the detector for PET systems due to the high cost of six-sided readout electronics and carrying out segmentation of a monolithic cubic scintillator in three dimensions using the subsurface laser engraving (SSLE) technique. In this work, we propose a more practical X’tal cube with a two-sided readout detector, which is made of crystal bars segmented in the height direction only by using the SSLE technique. We developed two types of prototype detectors with a 3 mm cubic segment and a 1.5 mm cubic segment by using 3  ×  3  ×  20 mm3 and 1.5  ×  1.5  ×  20 mm3 crystal bars segmented into 7 and 13 DOI segments, respectively, using the SSLE technique. First, the performance of the detector, composed of one crystal bar with different DOI segments and two thorough silicon via (TSV) multi-pixel photon counters (MPPCs) as readout at both ends of the crystal bar, were evaluated in order to demonstrate the capability of the segmented crystal bars as a DOI detector. Then, performance evaluation was carried out for a 4  ×  4 crystal array of 3  ×  3  ×  20 mm3 with 7 DOI segments and an 8  ×  8 crystal array of 1.5  ×  1.5  ×  20 mm3 with 13 DOI segments. Each readout included a 4  ×  4 channel of the 3  ×  3 mm2 active area of the TSV MPPCs. The three-dimensional position maps of the detectors were obtained by the Anger-type calculation. All the segments in the 4  ×  4 array were identified very clearly when there was air between the crystal bars, as each crystal bar was coupled to one channel of the MPPCs; however, it was necessary to optimize optical conditions between crystal bars for the 8  ×  8 array because of light sharing between crystal bars coupled to one channel of the MPPCs. The optimization was performed for the 8  ×  8 array by inserting reflectors fully or partially between the crystal bars and the best crystal identification performance was obtained with the partial reflectors between the crystal bars. The mean energy resolutions at the 511 keV photo peak for the 4  ×  4 array with air between the crystal bars and for the 8  ×  8 array with partial reflectors between the crystal bars were 10.1%  ±  0.3% and 10.8%  ±  0.8%, respectively. Timing resolutions of 783  ±  36 ps and 1.14  ±  0.22 ns were obtained for the detectors composed of the 4  ×  4 array and the 8  ×  8 array with partial reflectors, respectively. These values correspond to single photon timing resolutions. Practical X’tal cubes with 3 mm and 1.5 mm DOI resolutions and two-sided readout were developed.

Development of a dual-ended readout detector with segmented crystal bars made using a subsurface laser engraving technique.

PubMed

Mohammadi, Akram; Yoshida, Eiji; Nishikido, Fumihiko; Nitta, Munetaka; Shimizu, Keiji; Sakai, Toshiaki; Yamaya, Taiga

2018-01-11

Depth of interaction (DOI) information is indispensable to improving the sensitivity and spatial resolution of positron emission tomography (PET) systems, especially for small field-of-view PET such as small animal PET and human brain PET. We have already developed a series of X'tal cube detectors for isotropic spatial resolution and we obtained the best isotropic resolution of 0.77 mm for detectors with six-sided readout. However, it is still challenging to apply the detector for PET systems due to the high cost of six-sided readout electronics and carrying out segmentation of a monolithic cubic scintillator in three dimensions using the subsurface laser engraving (SSLE) technique. In this work, we propose a more practical X'tal cube with a two-sided readout detector, which is made of crystal bars segmented in the height direction only by using the SSLE technique. We developed two types of prototype detectors with a 3 mm cubic segment and a 1.5 mm cubic segment by using 3  ×  3  ×  20 mm 3 and 1.5  ×  1.5  ×  20 mm 3 crystal bars segmented into 7 and 13 DOI segments, respectively, using the SSLE technique. First, the performance of the detector, composed of one crystal bar with different DOI segments and two thorough silicon via (TSV) multi-pixel photon counters (MPPCs) as readout at both ends of the crystal bar, were evaluated in order to demonstrate the capability of the segmented crystal bars as a DOI detector. Then, performance evaluation was carried out for a 4  ×  4 crystal array of 3  ×  3  ×  20 mm 3 with 7 DOI segments and an 8  ×  8 crystal array of 1.5  ×  1.5  ×  20 mm 3 with 13 DOI segments. Each readout included a 4  ×  4 channel of the 3  ×  3 mm 2 active area of the TSV MPPCs. The three-dimensional position maps of the detectors were obtained by the Anger-type calculation. All the segments in the 4  ×  4 array were identified very clearly when there was air between the crystal bars, as each crystal bar was coupled to one channel of the MPPCs; however, it was necessary to optimize optical conditions between crystal bars for the 8  ×  8 array because of light sharing between crystal bars coupled to one channel of the MPPCs. The optimization was performed for the 8  ×  8 array by inserting reflectors fully or partially between the crystal bars and the best crystal identification performance was obtained with the partial reflectors between the crystal bars. The mean energy resolutions at the 511 keV photo peak for the 4  ×  4 array with air between the crystal bars and for the 8  ×  8 array with partial reflectors between the crystal bars were 10.1%  ±  0.3% and 10.8%  ±  0.8%, respectively. Timing resolutions of 783  ±  36 ps and 1.14  ±  0.22 ns were obtained for the detectors composed of the 4  ×  4 array and the 8  ×  8 array with partial reflectors, respectively. These values correspond to single photon timing resolutions. Practical X'tal cubes with 3 mm and 1.5 mm DOI resolutions and two-sided readout were developed.

Local readout enhancement for detuned signal-recycling interferometers

NASA Astrophysics Data System (ADS)

Rehbein, Henning; Müller-Ebhardt, Helge; Somiya, Kentaro; Li, Chao; Schnabel, Roman; Danzmann, Karsten; Chen, Yanbei

2007-09-01

High power detuned signal-recycling interferometers currently planned for second-generation interferometric gravitational-wave detectors (for example Advanced LIGO) are characterized by two resonances in the detection band, an optical resonance and an optomechanical resonance which is upshifted from the suspension pendulum frequency due to the so-called optical-spring effect. The detector’s sensitivity is enhanced around these two resonances. However, at frequencies below the optomechanical resonance frequency, the sensitivity of such interferometers is significantly lower than non-optical-spring configurations with comparable circulating power; such a drawback can also compromise high-frequency sensitivity, when an optimization is performed on the overall sensitivity of the interferometer to a class of sources. In this paper, we clarify the reason for such a low sensitivity, and propose a way to fix this problem. Motivated by the optical-bar scheme of Braginsky, Gorodetsky, and Khalili, we propose to add a local readout scheme which measures the motion of the arm-cavity front mirror, which at low frequencies moves together with the arm-cavity end mirror, under the influence of gravitational waves. This scheme improves the low-frequency quantum-noise-limited sensitivity of optical-spring interferometers significantly and can be considered as an incorporation of the optical-bar scheme into currently planned second-generation interferometers. On the other hand it can be regarded as an extension of the optical-bar scheme. Taking compact binary inspiral signals as an example, we illustrate how this scheme can be used to improve the sensitivity of the planned Advanced LIGO interferometer, in various scenarios, using a realistic classical-noise budget. We also discuss how this scheme can be implemented in Advanced LIGO with relative ease.

International Space Station Laboratory "Destiny" Hardware Move From MSFC to KSC

NASA Technical Reports Server (NTRS)

Welch, Andrew C.

2003-01-01

The transportation and handling of space flight hardware always demands the utmost care and planning. This was especially true when it came time to move the International Space Station lab module "Destiny" from its manufacturing facility at the Marshall Space Flight Center (MSFC) to the launch facility at the Kennedy Space Center in Florida. Good logistics management was the key to the coordination of the large team required to move the lab from the MSFC manufacturing facility 12 miles to the Huntsville International Airport. Overhead signs, power lines, and traffic lights had to be removed, law enforcement had to be coordinated and a major highway had to be completely shut down during the transportation phase of the move. The team responded well, and the move was accomplished on time with no major difficulties.

Search for a low-mass pseudoscalar Higgs boson produced in association with a $$b\\bar{b}$$ pair in pp collisions at √s = 8 TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khachatryan, Vardan

A search is reported for a light pseudoscalar Higgs boson decaying to a pair of τ leptons, produced in association with amore » $$b\\bar{b}$$ pair, in the context of two-Higgs-doublet models. The results are based on pp collision data at a centre-of-mass energy of 8 TeV collected by the CMS experiment at the LHC and corresponding to an integrated luminosity of 19.7 fb -1. Pseudoscalar boson masses between 25 and 80 GeV are probed. There was no evidence for a pseudoscalar boson found and upper limits were set on the production cross section times branching fraction to t pairs between 7 and 39 pb at the 95% confidence level. This search excludes a pseudoscalar Higgs boson with mass below 80 GeV, in Type II two-Higgs-doublet models with a negative coupling of standard model-like Higgs boson to down-type fermions.« less

Running bumps from stealth bosons

NASA Astrophysics Data System (ADS)

Aguilar-Saavedra, J. A.

2018-03-01

For the `stealth bosons' S, light boosted particles with a decay S → A A → q \\bar{q} q \\bar{q} into four quarks and reconstructed as a single fat jet, the groomed jet mass has a strong correlation with groomed jet substructure variables. Consequently, the jet mass distribution is strongly affected by the jet substructure selection cuts when applied on the groomed jet. We illustrate this fact by recasting a CMS search for low-mass dijet resonances and show a few representative examples. The mass distributions exhibit narrow and wide bumps at several locations in the 100-300 GeV range, between the masses of the daughter particles A and the parent particle S, depending on the jet substructure selection. This striking observation introduces several caveats when interpreting and comparing experimental results, for the case of non-standard signatures. The possibility that a single boosted particle decaying hadronically produces multiple bumps, at quite different jet masses, and depending on the event selection, brings the anomaly chasing game to the next level.

The Secular Evolution Of Disc Galaxies And The Origin Of Exponential And Double Exponential Surface Density Profiles

NASA Astrophysics Data System (ADS)

Elmegreen, Bruce G.

2016-10-01

Exponential radial profiles are ubiquitous in spiral and dwarf Irregular galaxies, but the origin of this structural form is not understood. This talk will review the observations of exponential and double exponential disks, considering both the light and the mass profiles, and the contributions from stars and gas. Several theories for this structure will also be reviewed, including primordial collapse, bar and spiral torques, clump torques, galaxy interactions, disk viscosity and other internal processes of angular momentum exchange, and stellar scattering off of clumpy structure. The only process currently known that can account for this structure in the most theoretically difficult case is stellar scattering off disks clumps. Stellar orbit models suggest that such scattering can produce exponentials even in isolated dwarf irregulars that have no bars or spirals, little shear or viscosity, and profiles that go out too far for the classical Mestel case of primordial collapse with specific angular momentum conservation.

Search for a low-mass pseudoscalar Higgs boson produced in association with a $$b\\bar{b}$$ pair in pp collisions at √s = 8 TeV

DOE PAGES

Khachatryan, Vardan

2016-05-06

A search is reported for a light pseudoscalar Higgs boson decaying to a pair of τ leptons, produced in association with amore » $$b\\bar{b}$$ pair, in the context of two-Higgs-doublet models. The results are based on pp collision data at a centre-of-mass energy of 8 TeV collected by the CMS experiment at the LHC and corresponding to an integrated luminosity of 19.7 fb -1. Pseudoscalar boson masses between 25 and 80 GeV are probed. There was no evidence for a pseudoscalar boson found and upper limits were set on the production cross section times branching fraction to t pairs between 7 and 39 pb at the 95% confidence level. This search excludes a pseudoscalar Higgs boson with mass below 80 GeV, in Type II two-Higgs-doublet models with a negative coupling of standard model-like Higgs boson to down-type fermions.« less

Search for a pseudoscalar boson decaying into a Z boson and the 125 GeV Higgs boson in ℓ⁺ℓ⁻$$b\\bar{b}$$ final states

DOE PAGES

Khachatryan, Vardan

2015-07-09

Results are reported on a search for decays of a pseudoscalar A boson into a Z boson and a light scalar h boson, where the Z boson decays into a pair of oppositely-charged electrons or muons, and the h boson decays intomore » $$b\\bar{b}$$. The search is based on data from proton–proton collisions at a center-of-mass energy √s = 8 TeV collected with the CMS detector, corresponding to an integrated luminosity of 19.7 fb⁻¹. The h boson is assumed to be the standard model-like Higgs boson with a mass of 125 GeV. With no evidence for signal, upper limits are obtained on the product of the production cross section and the branching fraction of the A boson in the Zh channel. Results are also interpreted in the context of two Higgs doublet models.« less

A linear model fails to predict orientation selectivity of cells in the cat visual cortex.

PubMed Central

Volgushev, M; Vidyasagar, T R; Pei, X

1996-01-01

1. Postsynaptic potentials (PSPs) evoked by visual stimulation in simple cells in the cat visual cortex were recorded using in vivo whole-cell technique. Responses to small spots of light presented at different positions over the receptive field and responses to elongated bars of different orientations centred on the receptive field were recorded. 2. To test whether a linear model can account for orientation selectivity of cortical neurones, responses to elongated bars were compared with responses predicted by a linear model from the receptive field map obtained from flashing spots. 3. The linear model faithfully predicted the preferred orientation, but not the degree of orientation selectivity or the sharpness of orientation tuning. The ratio of optimal to non-optimal responses was always underestimated by the model. 4. Thus non-linear mechanisms, which can include suppression of non-optimal responses and/or amplification of optimal responses, are involved in the generation of orientation selectivity in the primary visual cortex. PMID:8930828

Simulation of Watts Bar Unit 1 Initial Startup Tests with Continuous Energy Monte Carlo Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Godfrey, Andrew T; Gehin, Jess C; Bekar, Kursat B

2014-01-01

The Consortium for Advanced Simulation of Light Water Reactors* is developing a collection of methods and software products known as VERA, the Virtual Environment for Reactor Applications. One component of the testing and validation plan for VERA is comparison of neutronics results to a set of continuous energy Monte Carlo solutions for a range of pressurized water reactor geometries using the SCALE component KENO-VI developed by Oak Ridge National Laboratory. Recent improvements in data, methods, and parallelism have enabled KENO, previously utilized predominately as a criticality safety code, to demonstrate excellent capability and performance for reactor physics applications. The highlymore » detailed and rigorous KENO solutions provide a reliable nu-meric reference for VERAneutronics and also demonstrate the most accurate predictions achievable by modeling and simulations tools for comparison to operating plant data. This paper demonstrates the performance of KENO-VI for the Watts Bar Unit 1 Cycle 1 zero power physics tests, including reactor criticality, control rod worths, and isothermal temperature coefficients.« less

Recent Results from the Daya Bay Experiment

NASA Astrophysics Data System (ADS)

Yu, Z. Y.; Daya Bay Collaboration

2017-09-01

The Daya Bay reactor neutrino experiment was designed to precisely measure the neutrino oscillation parameter θ 13 via the relative comparison of neutrino rates and spectra at different baselines. Eight identically designed detectors were deployed in two near experimental halls and a far hall. Six 2.9 GWth nuclear power reactors served as intense {\\bar ν _e} sources. Since Dec. 2011, the experiment has been running stably. The latest neutrino oscillation results were based on 1230 days of data. Analysis using a three-flavor oscillation model yielded sin22θ 13 = 0.0841 ± 0.0027(stat.) ± 0.0019(syst.), and effective neutrino mass-squared difference ≤ft| {Δ mee^2} \\right| = ≤ft( {2.50 +/- 0.06≤ft( {stat.} \\right) +/- 0.06≤ft( {syst.} \\right)} \\right) × {10 - 3}e{V^2}. Besides, results from the absolute measurement of reactor {\\bar ν _e} flux and energy spectrum, and a search for a light sterile neutrino are also presented.

The New BaBar Data Reconstruction Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceseracciu, Antonio

2003-06-02

The BaBar experiment is characterized by extremely high luminosity, a complex detector, and a huge data volume, with increasing requirements each year. To fulfill these requirements a new control system has been designed and developed for the offline data reconstruction system. The new control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of OO design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system is activelymore » distributed, enforces the separation between different processing tiers by using different naming domains, and glues them together by dedicated brokers. It provides a powerful Finite State Machine framework to describe custom processing models in a simple regular language. This paper describes this new control system, currently in use at SLAC and Padova on {approx}450 CPUs organized in 12 farms.« less

The BaBar Data Reconstruction Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceseracciu, A

2005-04-20

The BaBar experiment is characterized by extremely high luminosity and very large volume of data produced and stored, with increasing computing requirements each year. To fulfill these requirements a Control System has been designed and developed for the offline distributed data reconstruction system. The control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of OO design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system ismore » distributed in a hierarchical way: the top-level system is organized in farms, farms in services, and services in subservices or code modules. It provides a powerful Finite State Machine framework to describe custom processing models in a simple regular language. This paper describes the design and evolution of this control system, currently in use at SLAC and Padova on {approx}450 CPUs organized in 9 farms.« less

Overview on new diode lasers for defense applications

NASA Astrophysics Data System (ADS)

Neukum, Joerg

2012-11-01

Diode lasers have a broad wavelength range, from the visible to beyond 2.2μm. This allows for various applications in the defense sector, ranging from classic pumping of DPSSL in range finders or target designators, up to pumping directed energy weapons in the 50+ kW range. Also direct diode applications for illumination above 1.55μm, or direct IR countermeasures are of interest. Here an overview is given on some new wavelengths and applications which are recently under discussion. In this overview the following aspects are reviewed: • High Power CW pumps at 808 / 880 / 940nm • Pumps for DPAL - Diode Pumped Alkali Lasers • High Power Diode Lasers in the range < 1.0 μm • Scalable Mini-Bar concept for high brightness fiber coupled modules • The Light Weight Fiber Coupled module based on the Mini-Bar concept Overall, High Power Diode Lasers offer many ways to be used in new applications in the defense market.

Searching for beauty-fully bound tetraquarks using lattice nonrelativistic QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, Ciaran; Eichten, Estia; Davies, Christine T. H.

Motivated by multiple phenomenological considerations, we perform the first search for the existence of amore » $$\\bar{bb}bb$$ tetraquark bound state with a mass below the lowest noninteracting bottomonium-pair threshold using the first-principles lattice nonrelativistic QCD methodology. Here, we use a full S-wave color/spin basis for the $$\\bar{bb}bb$$ operators in the three 0 ++, 1 +- and 2 ++ channels. We employ four gluon field ensembles at multiple lattice spacing values ranging from a=0.06–0.12 fm, all of which include u, d, s and c quarks in the sea, and one ensemble which has physical light-quark masses. Additionally, we perform novel exploratory work with the objective of highlighting any signal of a near threshold tetraquark, if it existed, by adding an auxiliary potential into the QCD interactions. With our results we find no evidence of a QCD bound tetraquark below the lowest noninteracting thresholds in the channels studied.« less

The BaBar Data Reconstruction Control System

NASA Astrophysics Data System (ADS)

Ceseracciu, A.; Piemontese, M.; Tehrani, F. S.; Pulliam, T. M.; Galeazzi, F.

2005-08-01

The BaBar experiment is characterized by extremely high luminosity and very large volume of data produced and stored, with increasing computing requirements each year. To fulfill these requirements a control system has been designed and developed for the offline distributed data reconstruction system. The control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of object oriented (OO) design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system is distributed in a hierarchical way: the top-level system is organized in farms, farms in services, and services in subservices or code modules. It provides a powerful finite state machine framework to describe custom processing models in a simple regular language. This paper describes the design and evolution of this control system, currently in use at SLAC and Padova on /spl sim/450 CPUs organized in nine farms.

Searching for beauty-fully bound tetraquarks using lattice nonrelativistic QCD

DOE PAGES

Hughes, Ciaran; Eichten, Estia; Davies, Christine T. H.

2018-03-14

Motivated by multiple phenomenological considerations, we perform the first search for the existence of amore » $$\\bar{bb}bb$$ tetraquark bound state with a mass below the lowest noninteracting bottomonium-pair threshold using the first-principles lattice nonrelativistic QCD methodology. Here, we use a full S-wave color/spin basis for the $$\\bar{bb}bb$$ operators in the three 0 ++, 1 +- and 2 ++ channels. We employ four gluon field ensembles at multiple lattice spacing values ranging from a=0.06–0.12 fm, all of which include u, d, s and c quarks in the sea, and one ensemble which has physical light-quark masses. Additionally, we perform novel exploratory work with the objective of highlighting any signal of a near threshold tetraquark, if it existed, by adding an auxiliary potential into the QCD interactions. With our results we find no evidence of a QCD bound tetraquark below the lowest noninteracting thresholds in the channels studied.« less