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Sample records for black chrome solar

  1. Selective coating for solar panels. [using black chrome and black nickel

    NASA Technical Reports Server (NTRS)

    Mcdonald, G. E. (Inventor)

    1977-01-01

    The energy absorbing properties of solar heating panels are improved by depositing a black chrome coating of controlled thickness on a specially prepared surface of a metal substrate. The surface is prepared by depositing a dull nickel on the substrate, and the black chrome is plated on this low emittance surface to a thickness between 0.5 micron and 2.5 microns.

  2. Fundamental studies of black chrome for solar collector use

    NASA Technical Reports Server (NTRS)

    Mcdonald, G.; Buzek, B.; Curtis, H.

    1976-01-01

    The thicknesses of black chrome plated for various times have been measured from electron photomicrographs and correlated with the solar spectrum absorptance and infrared emittance as calculated from spectral reflectance measurements. The maximum absorptance is reached at an average thickness of 0.5 micrometer. The emittance increases only slightly up to 1.0 micrometer but increases rapidly at thickness above 1.0 micrometer.

  3. Refinement in black chrome for use as a solar selective coating

    NASA Technical Reports Server (NTRS)

    Mcdonald, G. E.

    1974-01-01

    Black chrome is significant as a solar selective coating because the current extensive use of black chrome in the electroplating industry as a durable decorative finish makes black chrome widely available on a commercial scale and potentially low in cost as a solar selective coating. Black-chrome deposits were modified by underplating with dull nickel or by being plated on rough surfaces. Both of these procedures increased the visible absorptance. There was no change in the infrared reflectance for the dull-nickel - black-chrome combination from that reported for the bright-nickel - black-chrome combination. However, the bright-nickel - black-chrome coating plated on rough surfaces indicated a slight decrease in infrared reflectance. As integrated over the solar spectrum for air mass 2, the reflectance of the dull-nickel - black-chrome coating was 0.077, of the bright-nickel - black-chrome coating plated on a 0.75-micron (30-microinch) surface was 0.070, of the bright-nickel - black-chrome coating plated on a 2.5 micron (100-microinch) surface was 0.064. The corresponding values for the bright-nickel - black-chrome coating on a 0.0125-micron (0.5-microinch) surface, two samples of black nickel, and two samples of Nextrel black paint were 0.132, 0.123, 0.133, and 0.033, respectively.

  4. Optical modeling of black chrome solar-selective coatings

    SciTech Connect

    Sweet, J.N.; Pettit, R.B.

    1982-07-01

    Various investigations of coating microstructure are reviewed and the results of these studies are used to develop a picture of the microstructure of black chrome films plated from the Harshaw Chromonyx bath. In this model, the black chrome film is composed of roughly spherical particles which may tend to cluster together. These particles in turn are composed of small crystallites of metallic chrome and various oxides of chrome. The film void volume fraction appears to be greater than or equal to 0.6. The microstructural picture has been idealized to facilitate calculations of the spectral reflectance for films deposited onto nickel substrates and for freestanding or stripped films. In the idealized model, the metallic chromium is assumed to be in the form of spherical crystallites with concentric shells of Cr/sub 2/O/sub 3/ and the crystallite volume fraction is assumed to increase with depth into the film. Various experimental data are utilized to define film thickness, average volume fraction of Cr + Cr/sub 2/O/sub 3/, and volume ratio of Cr to Cr + Cr/sub 2/O/sub 3/. Both the Maxwell-Garnett (MG) and the Bruggeman effective medium theories for the dielectric constant of a composite media are reviewed. The extension of the MG theory to high inclusion volume fractions is discussed. Various forms of the MG theory and the Bruggeman theory are then utilized in reflectance calculations for both regular and stripped films.The results indicate that the MG formalism provides the best overall description of the optical response of black chrome films. Both model and experiment show that the solar absorptance initially decreases slowly as the amount of Cr/sub 2/O/sub 3/ increases; however a rapid decrease occurs when the Cr/sub 2/O/sub 3/ content passes 70 vol %.

  5. Oxidation of electrodeposited black chrome selective solar absorber films

    SciTech Connect

    Holloway, P.H.; Shanker, K.; Pettit, R.B.; Sowell, R.R.

    1980-01-01

    X-ray photoelectron and Auger electron spectroscopies have been used to study the composition and oxidation of electrodeposited black chrome films. The outer layer of the film is Cr/sub 2/O/sub 3/ with the inner layer being a continuously changing mixture of Cr + Cr/sub 2/O/sub 3/. Initially, approximately 40% by volume of the film is combined as Cr/sub 2/O/sub 3/, and the volume percentage of Cr/sub 2/O/sub 3/ increases to greater than 60% after only 136 hours at 250/sup 0/C. After approximately 3600 hours at 400/sup 0/C, the volume percentage of Cr/sub 2/O/sub 3/ increased to as high as 80%. The thermal emittance decreased approximately linearly with increasing oxide content, while the solar absorptance remained constant until the percentage of Cr/sub 2/O/sub 3/ exceeded approximately 70%. Oxidation was slower when the Cr/sup +3/ concentration in the plating bath was reduced from 16 g/l to 8 g/l, and when black chrome was deposited on stainless steel rather than sulfamate nickel.

  6. Variation of solar-selective properties of black chrome with plating time

    NASA Technical Reports Server (NTRS)

    Mcdonald, G. E.; Curtis, H. B.

    1975-01-01

    The spectral reflectance properties of a commercially prepared black chrome over dull nickel, both plated on steel, for various plating times of the black chrome were measured. The plating current was 180 amperes per square foot. Values of absorptance integrated over the solar spectrum, and of infrared emittance integrated over black-body radiation at 250 F were obtained. It is shown that plating between one and two minutes produces the optimum combination of highest heat absorbed and lowest heat lost by radiation.

  7. Metallurgical analysis and high temperature degradation of the black chrome solar selective absorber

    SciTech Connect

    Lampert, C.M.

    1980-03-01

    The characteristics of black chrome, a solar selective absorber, have been the object of much interest by solar materials scientists. For this study, a well known coating, Harshaw Chemical Company's Chromonyx was selected for detailed scrutiny of its properties and degradation modes when exposed to high temperatures. Both as-plated and annealed microstructural models were presented. Technical means used in this microstructural characterization were: scanning and transmission electron microscopy, Auger depth profiling hemispherical reflectance and energy dispersive x-ray analysis. From these results a physical metallurgical model for wavelength selective properties of the coating was developed. Thus, it was observed that black chrome degraded as Cr/sub 2/O/sub 3/ oxide particles grew and chromium depleted. This effect was pronounced in air and to a lesser degree in medium vacuum. Oxidation by preferential diffusion and outgassing which causes structural changes, may take place.

  8. Black-chrome solar-selective coatings electrodeposited on metallized-glass tubes

    SciTech Connect

    Grimmer, D P; Collier, R K

    1981-01-01

    Glass tubes, initially metallized with thin layers of chromium and copper, were electroplated with copper and black chrome. The optical properties of the black-chrome-plated tubes were excellent with ..cap alpha../sub s/ approx. = 0.94 and epsilon/sub TH/ (25/sup 0/C) approx. = 0.08. Thermal-cycling tests of the tubes revealed relatively stable optical properties until temperatures around 400/sup 0/C in vacuum were reached.

  9. Surface structure and the optical properties of black chrome

    NASA Astrophysics Data System (ADS)

    Smith, G. B.; McPhedran, R. C.; Derrick, G. H.

    1985-04-01

    A new optical model is presented for solar-selective black chrome. Surface texture is shown to be the primary factor which gives thin films of black chrome a uniformly high absorptance in the visible and near-infrared regions. Internal composition of the films is a secondary influence on their optical properties. We present results consistent with experimental data obtained from films having widely varying structures and compositions, both before and after heat treatment. Our optical model does not rely on the quasistatic approximation, hitherto universally employed in theoretical studies of solar-selective black chrome. Instead, we use a rigorous diffraction formulation for doubly-periodic surfaces (bigratings). The key parameters of the surface morphology are determined from stereo-pair electronmicrographs, and are used in the bigrating model. We present the predicted variation of spectral absorptance with wavelength, as well as integrated absorptance and thermal emittance, for roughened chromium. We give results both for bare metal, and for the metal conformally overcoated either with a thin layer of Cr2O3 or with a Cr/Cr2O3 cermet. Various shapes of surface features are examined, and surface profile is shown not to be crucial in determining optical properties.

  10. Microstructural and mechanical property evaluation of black chrome and zinc oxide coated solar collectors. Annual report No. II, June 1979-March 1980

    SciTech Connect

    Inal, O T

    1980-01-01

    Plating parameters for black-chrome system were optimized with respect to selectivity utilizing simplex evolutionary operation procedures in sixteen sets of experiments. Overgrowths produced with the optimized parameters were then evaluated for optical, structural, thermal stability and mechanical properties. It is observed that the coatings produced possess consistently high selectivity values (approx. 10), are durable against exposure to high temperature (> 400/sup 0/C in air and > 500/sup 0/C in neutral atmosphere), are well attached to their structure (> 340 kg/cm/sup 2/), and are quite ductile (bent to 131.5/sup 0/ previous to fracture) and reasonably remain so following exposure to 500/sup 0/C (2 hrs) in air (84.2% bend previous to fracture). Black zinc oxide surfaces created on leaf zinc, electroplated zinc on steel, and hot-dip zinc coated steel substrates show selectivity values that vary between 6-9, are seen to maintain their physical integrity as well as optical properties following exposure to 250/sup 0/C (2 hrs) in air, possess high strength of attachment to their substrates (> 285 kg/cm/sup 2/), and are quite ductile (170/sup 0/ bend previous to fracture) and maintain a reasonably high ductility (121/sup 0/ bend previous to fracture) following exposure to 250/sup 0/C (2 hrs) in air. Structural analysis of both overgrowths show them to consist of oxide particles within which elemental component of the oxide is seen to be distributed in the unassociated form. The plating parameters utilized in deposition of the coatings are seen to alter quantity and distribution of the elemental component and effect optical properties of these surfaces. These composite particles are seen to be of various sizes but the distribution of these particles are seen to be constant throughout the overgrowth.

  11. Survey of coatings for solar collectors. [ceramic enamels and chromium

    NASA Technical Reports Server (NTRS)

    Mcdonald, G. E.

    1974-01-01

    Ceramic enamel is found to be more solar selective, (i.e., has high solar absorptance in combination with low infrared emittance) than organic enamel, but neither is as solar selective as black chrome, black copper, black zinc, or black nickel. Ceramic enamel is matched only by black chrome in durability and wide availability. Ceramic enamel and organic enamel have approximately the same cost, and both are currently slightly lower in cost than black chrome, black copper, or black zinc. Black nickel is relatively unavailable and, because of that, realistic cost comparisons are not possible.

  12. Solar selective black cobalt: preparation, structure, and thermal stability

    SciTech Connect

    Smith, G.B.; Ignatiev, A.; Zajac, G.

    1980-08-01

    In the quest for an electroplated selective black coating stable to 500 /sup 0/C in air, black cobalts have been prepared by three techniques to yield (a) plated cobalt sulphides, (b) plated cobalt oxide-hydroxide, and (c) cobalt oxide prepared by thermal oxidation of electropolated cobalt metal. The optical properties of the various coatings are analyzed before and after exposure to air for extended periods of time at temperatures in the 300 /sup 0/--500 /sup 0/C range. The sulfide black cobalt is not acceptable as a high-temperature selective absorber due to severe thermal degradation. The plated oxide is a good selective absorber to about 400 /sup 0/C, and the thermally oxidized black to a slightly higher temperature, but degrades at 500 /sup 0/C. Structure studies via scanning electron microscopy (SEM), Auger electron spectroscopy (AES), and x-ray photoemission spectroscopy (XPS) are reported which yield a full account of the coating chemistry before and after heating. The studies reveal that the high solar absorptance of the acceptable black cobalt coatings is due to a continuation of a porous outer layer grading into nondense oxides of cobalt; either CoO or Co/sub 3/O/sub 4/, depending on the film. Absorption is intrinsic but not due to metal particles as in black chrome. A limited amount of optical degradation occurs upon heating the oxide black cobalt in air due to oxidation of hydroxide. However, the major degradation problem is shown to be substrate oxidation in contrast to black chrome where film oxidation is the principal problem.

  13. Black Liquid Solar Collector Demonstrator.

    ERIC Educational Resources Information Center

    Weichman, F. L.; Austen, D. J.

    1979-01-01

    Describes the details of constructing, and use of, a solar collector. Uses a black liquid to absorb the energy, the thermosyphon effect to drive the liquid through the collector, and a floodlamp as a surrogate sun. (GA)

  14. Solar energy absorption characteristics and the effects of heat on the optical properties of several coatings

    NASA Technical Reports Server (NTRS)

    Lowery, J. R.

    1981-01-01

    The solar energy absorption characteristics of several high temperature coatings were determined and effects of heat on these coatings were evaluated. Included in the investigation were an electroplated alloy of black chrome and vanadium, electroplated black chrome, and chemically colored 316 stainless steel. Each of the coatings possessed good selective solar energy absorption properties at laboratory ambient temperature. Measured at a temperature of 700 K (800 F), the emittances of black chrome, black chrome vanadium, and colored stainless steel were 0.11, 0.61, and 0.15, respectively. Black chrome and black chrome vanadium did not degrade optically in the presence of high heat (811 K (1000 F)). Chemically colored stainless steel showed slight optical degradation when exposed to moderately high heat (616 K (650 F)0, but showed more severe degradation at exposure temperatures beyond this level. Each of the coatings showed good corrosion resistance to a salt spray environment.

  15. Survey of coatings for solar collectors

    NASA Technical Reports Server (NTRS)

    Mcdonald, G. E.

    1975-01-01

    Optimum solar selective properties of black chrome require some tailoring of current and time for plating solution being used. Black zinc is produced from high zinc electroplate by subsequent conversion with chromate dip. Measurements have also been made of reflectance of previously known solar selective coatings of black copper and electroplated black nickel.

  16. Optimized Selective Coatings for Solar Collectors

    NASA Technical Reports Server (NTRS)

    Mcdonald, G.; Curtis, H. B.

    1967-01-01

    The spectral reflectance properties of black nickel electroplated over stainless steel and of black copper produced by oxidation of copper sheet were measured for various plating times of black nickel and for various lengths of time of oxidation of the copper sheet, and compared to black chrome over nickel and to converted zinc. It was determined that there was an optimum time for both plating of black nickel and for the oxidation of copper black. At this time the solar selective properties show high absorptance in the solar spectrum and low emittance in the infrared. The conditions are compared for production of optimum optical properties for black nickel, black copper, black chrome, and two black zinc conversions which at the same conditions had absorptances of 0.84, 0.90, 0.95, 0.84, and 0.92, respectively, and emittances of 0.18, 0.08, 0.09, 0.10, and 0.08, respectively.

  17. The CHROME Honors Program

    NASA Technical Reports Server (NTRS)

    Wilson, Eleanor

    2002-01-01

    The CHROME Honors Program was designed as a two-week residential program for 9th and 1Oth grade students participating in CHROME clubs. The curriculum focused on the health sciences with instruction from: (1) the science and health curriculum of the Dozoretz National Program for Minorities in Applied Sciences (DNIMAS) Program of Norfolk State University (NSU); (2) the humanities curriculum of the NSU Honors Program; (3) NASA-related curriculum in human physiology. An Advisory Committee was formed to work with the Project Coordinator in the design of the summer program.

  18. Absorptive coating for aluminum solar panels

    NASA Technical Reports Server (NTRS)

    Desmet, D.; Jason, A.; Parr, A.

    1979-01-01

    Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

  19. Solar absorption characteristics of several coatings and surface finishes. [for solar energy collectors

    NASA Technical Reports Server (NTRS)

    Lowery, J. R.

    1977-01-01

    Solar absorption characteristics are established for several films potentially favorable for use as receiving surfaces in solar energy collectors. Included in the investigation were chemically produced black films, black electrodeposits, and anodized coatings. It was found that black nickel exhibited the best combination of selective optical properties of any of the coatings studied. A serious drawback to black nickel was its high susceptibility to degradation in the presence of high moisture environments. Electroplated black chrome generally exhibited high solar absorptivities, but the emissivity varied considerably and was also relatively high under some conditions. The black chrome had the greatest moisture resistance of any of the coatings tested. Black oxide coatings on copper and steel substrates showed the best combination of selective optical properties of any of the chemical conversion films studied.

  20. ALTERNATIVE TO CHROME ETCHING PROCESSES FOR METALS

    EPA Science Inventory

    Several industries, including the National Center for Manufacturing Science have initiated programs for chrome abatement. The programs, however, generally focus on chrome reduction by use of existing technologies and do not address the elimination of chrome in pretreatment proces...

  1. Thermal properties of carbon black aqueous nanofluids for solar absorption

    PubMed Central

    2011-01-01

    In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency. PMID:21767359

  2. Solar absorber material stability under high solar flux

    NASA Astrophysics Data System (ADS)

    Ignatiev, A.; Zajac, G.; Smith, G. B.

    1982-04-01

    Solar absorbing Black Chrome coatings have been exposed to high temperatures (350-400 C) under high solar fluxes (0.4 to 2.0 MW/sq m) to test for their stability under actual operating conditions. Field tests at the White Sands Solar Furnace have shown higher stability than expected from oven tested samples. Laboratory studies utilizing spectrally selective concentrated solar simulated radiation have indicated that the cause of the higher stability under solar irradiation is photo-stimulated desorption of oxygen bearing species at the absorber surface and resultant reduced oxidation of the absorber.

  3. Historically Black Colleges and Universities (HBCU) Solar Radiation Monitoring Network

    DOE Data Explorer

    The Historically Black Colleges and Universities (HBCU) Solar Radiation Monitoring Network operated from November 1985 through December 1996. The six-station network provided 5-minute averaged measurements of global and diffuse horizontal solar irradiance. The data were processed at the National Renewable Energy Laboratory (NREL) to improve the assessment of the solar radiation resources in the southeastern United States. Three of the stations also measured the direct-normal solar irradiance with a pyrheliometer mounted in an automatic sun tracker. All data are archived in the Standard Broadband Format (SBF) with quality-assessment indicators. Monthly data summaries and plots are also available for each month. In January 1997 the HBCU sites became part of the CONFRRM solar monitoring network.

  4. Low-Chrome/Chrome Free Refractories for Slagging Gasifiers

    SciTech Connect

    Bennett, J.P.; Kwong, K.-S.; Powell, C.P.; Thomas, H.; Petty, A.V., Jr.

    2007-01-01

    Gasifiers are containment vessels used to react carbon-containing materials with oxygen and water, producing syngas (CO and H2) that is used in chemical and power production. It is also a potential source of H2 in a future hydrogen economy. Air cooled slagging gasifiers are one type of gasifier, operating at temperatures from 1275-1575º C and at pressures of 400 psi or higher. They typically use coal or petroleum coke as the carbon source, materials which contain ash impurities that liquefy at the gasification temperatures, producing liquid slag in quantities of 100 or more tons/day, depending on the carbon fed rate and the percent ash present in the feedstock. The molten slag is corrosive to refractory linings, causing chemical dissolution and spalling. The refractory lining is composed of chrome oxide, alumina, and zirconia; and is replaced every 3-24 months. Gasifier users would like greater on-line availability and reliability of gasifier liners, something that has impacted gasifier acceptance by industry. Research is underway at NETL to improve refractory service life and to develop a no-chrome or low-chrome oxide alternative refractory liner. Over 250 samples of no- or low-chrome oxide compositions have been evaluated for slag interactions by cup testing; with potential candidates for further studies including those with ZrO2, Al2O3, and MgO materials. The development of improved liner materials is necessary if technologies such as IGCC and DOE’s Near Zero Emissions Advanced Fossil Fuel Power Plant are to be successful and move forward in the marketplace.

  5. Chrome - Free Aluminum Coating System

    NASA Technical Reports Server (NTRS)

    Bailey, John H.; Gugel, Jeffrey D.

    2010-01-01

    This slide presentation concerns the program to qualify a chrome free coating for aluminum. The program was required due to findings by OSHA and EPA, that hexavalent chromium, used to mitigate corrosion in aerospace aluminum alloys, poses hazards for personnel. This qualification consisted of over 4,000 tests. The tests revealed that a move away from Cr+6, required a system rather than individual components and that the maximum corrosion protection required pretreatment, primer and topcoat.

  6. Optimization of black diamond films for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Bellucci, Alessandro; Calvani, Paolo; Girolami, Marco; Orlando, Stefano; Polini, Riccardo; Trucchi, Daniele M.

    2016-09-01

    Black diamond, namely a surface textured diamond film able to absorb efficiently the sunlight, is developed by the use of ultrashort pulse laser treatments. With the aim of fabricating a 2D periodic surface structure, a double-step texturing process is implemented and compared to the single-step one, able to induce the formation of 1D periodic structures. Although the obtained sub-microstructure does not show a regular 2D periodicity, a solar absorptance of about 98% is achieved as well as a quantum efficiency enhanced of one order of magnitude with respect to the 1D periodic surface texturing.

  7. Hex Chrome Free Coatings for Electronics Overview

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2013-01-01

    The overall objective of the Hex Chrome Free Coatings for Electronics project is to evaluate and test pretreatment coating systems not containing hexavalent chrome in avionics and electronics housing applications. This objective will be accomplished by testing strong performing coating systems from prior NASA and DoD testing or new coating systems as determined by the stakeholders.

  8. Viscoelasticity Studies for Chrome-Free Leather

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chrome-free leather such as glutaraldehyde-tanned leather behaves very differently from chrome-tanned leather. Information regarding its viscoelasticity has not been reported. Hysteresis and stress relaxation are two essential properties associated with viscoelasticity. We have designed a cyclic ...

  9. Waste minimization in chrome plating

    SciTech Connect

    Scheuer, J.; Walter, K.; Nastasi, M.

    1996-09-01

    This is the final report of a one year laboratory directed research and development project at the Los Alamos National Laboratory (LANL). Traditional wet chemical electroplating techniques utilize toxic materials and pose environmental hazards in the disposal of primary baths and waste waters. Pollutants include metals and nonmetals, such as oil, grease, phosphates, and toxic and organic compounds. This project is focused on development of plasma source ion implantation (PSII), a novel and cost-effective surface modification technique, to minimize and ultimately eliminate waste generated in chrome plating. We are collaborating with and industrial partner to design material systems, utilize the PSII processes in existing Los Alamos experimental facilities, and analyze both material and performance characteristics.

  10. Characterizations of the mirror attenuator mosaic - Solar diffuser plate

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Avis, Lee M.; Gibson, M. A.; Kopia, Leonard P.

    1992-01-01

    The mirror attenuator mosaic (MAM), a solar diffuser plate, was used for the flight calibration of the broadband shortwave (0.2-5-microns) and total (0.2 to greater than 200-microns) Earth Radiation Budget Experiment scanning thermistor bolometer radiometers. The MAM solar-reflecting surface consisted of a tightly packed array of vacuum-deposited aluminum, concave spherical mirrors, while its solar-absorbing surface consisted of black chrome. The effective reflectance of the MAM was constant to within +/- 2 percent after almost 2 years in orbit, a marked improvement over earlier solar diffusers.

  11. Gold-black as IR Absorber and Solar Cell Enhancer

    SciTech Connect

    Peale, Robert E.; Cleary, Justin W.; Ishimaru, Manabu; Smith, C. W.; Baillie, K.; Colwell, J. E.; Beck, Kenneth M.; Joly, Alan G.; Edwards, Oliver; Fredricksen, C. J.

    2010-03-01

    Infrared absorbance and visible/near-IR excited plasmon resonances are investigated in gold-black, a porous nano-structured conducting film. A two level full factorial optimization study with evaporation-chamber pressure, boat current, substrate temperature, and degree of polymer infusion (for hardening) was performed. Polymer infusion was found generally to reduce absorbance in the long wave IR but has little effect at THz wavelengths, although for samples with the highest absorbance there is a slight improvement in the absorbance figure of merit (FOM) in both wavelength regimes. The characteristic length scales of the structured films vary considerably as a function of deposition parameters, but the IR FOM is found to be only weakly correlated with these distributions, which are determined by wavelet analysis of scanning electron micrographs images. Initial investigations of gold-black by photoelectron emission microscopy (PEEM) reveal plasmon resonances, which have potential to enhance the efficiency of thin film solar cells. For films with different characteristic length scales, the plasmon resonances appear in portions of the film with similar length scales.

  12. Can we afford to replace chrome?

    NASA Astrophysics Data System (ADS)

    Shelden, Gilbert V.; He, Long; Hector, Scott D.; Trybula, Walt

    2004-12-01

    Chrome-based absorbers have been the mainstay of the photomask industry for three decades. While chrome is attractive because of its durability and opacity, it conversely poses challenges for etch and repair. Due to large capital investments, any new absorber must be designed to work with existing scanners, mask writers, and mask inspection tools. Furthermore changing absorber materials may not improve defect control in mask blank fabrication, which is a paramount concern in blank fabrication. Consequently, blank manufacturers are reluctant to change from chrome. In terms of return on investment (ROI), the only driver to switch technologies is achieving higher mask and wafer yields. This is a reasonable assumption as both etch and repair tool suppliers believe a non-chrome material like tantalum (Ta) compounds would significantly improve their capabilities with known technologies. A high level estimate shows that with even aggressive improvement assumptions, a 100% conversion from chrome does not save money. Based on the current International SEMATECH (ISMT) cost of ownership (COO) model and improved yields for critical dimension (CD) and defects, a case can be made for converting at and below 100 nm ground rules. An industry wide conversion from chrome to a non-chrome absorber is estimated to cost $100M. By contrast, blank suppliers are reportedly spending "multiple" millions of dollars to improve chrome per year. A widespread concern is whether binary optical masks have enough life left to provide sufficient ROI. Optical lithography will continue to be of use in the foreseeable future. Even as leading-edge production moves to new technology, the main manufacturing volumes will continue to create significant demand for masks for 100 nm to 45 nm for many years. With the industry currently pushing extreme ultraviolet lithography (EUVL), the best situation would be for EUVL and optical lithography to choose the same absorber material. This creates a winning situation

  13. Chrome doped gallium arsenide evaluation

    SciTech Connect

    Pocha, M.D.; Morse, J.D.; Brazes, W.F.

    1987-10-10

    We received, for free, two sets of Chrome doped Gallium Arsenide (GaAs:Cr) wafers, one from Cominco Electronic Materials, Inc., and the other from Furakawa Electric Co., for the purpose of evaluation as potential material for high speed photoconductive detectors. In return for the free material we promised to give the two manufacturers feed back on our evaluation of these wafers. The primary purpose of this report is to present the results of our evaluation of these wafers and conclusions regarding the usefulness of heavily doped GaAs:Cr for photoconductive detectors. We have found that response times of less than 100 ps (FWHM) are possible with GaAs:Cr detectors, but that there are several time constants to the decay which result in very long ''tails'' to the impulse response of these detectors. These long tails are unacceptable for most detector applications, but there may be some special cases where GaAs:Cr could be used. 5 figs., 1 tab.

  14. Test results, Industrial Solar Technology parabolic trough solar collector

    SciTech Connect

    Dudley, V.E.; Evans, L.R.; Matthews, C.W.

    1995-11-01

    Sandia National Laboratories and Industrial Solar Technology are cost-sharing development of advanced parabolic trough technology. As part of this effort, several configurations of an IST solar collector were tested to determine the collector efficiency and thermal losses with black chrome and black nickel receiver selective coatings, combined with aluminized film and silver film reflectors, using standard Pyrex{reg_sign} and anti-reflective coated Pyrex{reg_sign} glass receiver envelopes. The development effort has been successful, producing an advanced collector with 77% optical efficiency, using silver-film reflectors, a black nickel receiver coating, and a solgel anti-reflective glass receiver envelope. For each receiver configuration, performance equations were empirically derived relating collector efficiency and thermal losses to the operating temperature. Finally, equations were derived showing collector performance as a function of input insolation value, incident angle, and operating temperature.

  15. Two ten-billion-solar-mass black holes at the centres of giant elliptical galaxies.

    PubMed

    McConnell, Nicholas J; Ma, Chung-Pei; Gebhardt, Karl; Wright, Shelley A; Murphy, Jeremy D; Lauer, Tod R; Graham, James R; Richstone, Douglas O

    2011-12-01

    Observational work conducted over the past few decades indicates that all massive galaxies have supermassive black holes at their centres. Although the luminosities and brightness fluctuations of quasars in the early Universe suggest that some were powered by black holes with masses greater than 10 billion solar masses, the remnants of these objects have not been found in the nearby Universe. The giant elliptical galaxy Messier 87 hosts the hitherto most massive known black hole, which has a mass of 6.3 billion solar masses. Here we report that NGC 3842, the brightest galaxy in a cluster at a distance from Earth of 98 megaparsecs, has a central black hole with a mass of 9.7 billion solar masses, and that a black hole of comparable or greater mass is present in NGC 4889, the brightest galaxy in the Coma cluster (at a distance of 103 megaparsecs). These two black holes are significantly more massive than predicted by linearly extrapolating the widely used correlations between black-hole mass and the stellar velocity dispersion or bulge luminosity of the host galaxy. Although these correlations remain useful for predicting black-hole masses in less massive elliptical galaxies, our measurements suggest that different evolutionary processes influence the growth of the largest galaxies and their black holes.

  16. Black wildebeest seek shade less and use solar orientation behavior more than do blue wildebeest.

    PubMed

    Lease, Hilary M; Murray, Ian W; Fuller, Andrea; Hetem, Robyn S

    2014-10-01

    Many ungulates, including wildebeest, seek shade and orient their bodies relative to incoming solar radiation in order to reduce environmental heat loads. Blue (Connochaetes taurinus) and black wildebeest (Connochaetes gnou), which co-exist artificially in some reserves in South Africa, are thought to adopt different thermoregulatory behaviors to mitigate high environmental heat loads. However, whether or not blue and black wildebeest use different behaviors to reduce heat loads in regions where they co-occur has never previously been examined. We compared the shade seeking and solar orientation behavior of free-ranging blue and black wildebeest in summer at three locations in South Africa where both species co-occur. We found that blue wildebeest exhibited more shade seeking behavior than did black wildebeest at all times of day, at all study sites. Black wildebeest remained in the sun but were more likely than blue wildebeest to orient their bodies parallel to the sun at all study sites, a behavior which reduces the amount of surface area exposed to incoming radiation. Black wildebeest were most likely to employ parallel solar orientation during the hottest times of the day when the sun was not directly overhead (i.e., solar noon ± 1 hour). We thus demonstrate that co-occurring blue and black wildebeest use different thermoregulatory behaviors to reduce high heat loads. It is possible that the lack of shade in the historical distribution of black wildebeest led to selective pressure for reliance on solar orientation. Differences in thermoregulatory behavior can affect species-specific heat loads, habitat use, body mass, fitness and grazing activity. Such differences may also allow blue and black wildebeest to inhabit separate microclimates within the same habitat, provided there is sufficient heterogeneity in vegetation structure, potentially facilitating reproductive isolation. PMID:25436964

  17. Black wildebeest seek shade less and use solar orientation behavior more than do blue wildebeest.

    PubMed

    Lease, Hilary M; Murray, Ian W; Fuller, Andrea; Hetem, Robyn S

    2014-10-01

    Many ungulates, including wildebeest, seek shade and orient their bodies relative to incoming solar radiation in order to reduce environmental heat loads. Blue (Connochaetes taurinus) and black wildebeest (Connochaetes gnou), which co-exist artificially in some reserves in South Africa, are thought to adopt different thermoregulatory behaviors to mitigate high environmental heat loads. However, whether or not blue and black wildebeest use different behaviors to reduce heat loads in regions where they co-occur has never previously been examined. We compared the shade seeking and solar orientation behavior of free-ranging blue and black wildebeest in summer at three locations in South Africa where both species co-occur. We found that blue wildebeest exhibited more shade seeking behavior than did black wildebeest at all times of day, at all study sites. Black wildebeest remained in the sun but were more likely than blue wildebeest to orient their bodies parallel to the sun at all study sites, a behavior which reduces the amount of surface area exposed to incoming radiation. Black wildebeest were most likely to employ parallel solar orientation during the hottest times of the day when the sun was not directly overhead (i.e., solar noon ± 1 hour). We thus demonstrate that co-occurring blue and black wildebeest use different thermoregulatory behaviors to reduce high heat loads. It is possible that the lack of shade in the historical distribution of black wildebeest led to selective pressure for reliance on solar orientation. Differences in thermoregulatory behavior can affect species-specific heat loads, habitat use, body mass, fitness and grazing activity. Such differences may also allow blue and black wildebeest to inhabit separate microclimates within the same habitat, provided there is sufficient heterogeneity in vegetation structure, potentially facilitating reproductive isolation.

  18. Chrome pyrope: an inclusion in natural diamond.

    PubMed

    Meyer, H O

    1968-06-28

    Electron probe analyses of garnets that are rich in magnesium and that occur as inclusions in natural diamonds show that the chrome-garnet end member, Mg(3)Cr(2)Si(3)O(12), is a major constituent (30 percent). PMID:17817353

  19. NASA TEERM Hexavalent Chrome Alternatives Projects

    NASA Technical Reports Server (NTRS)

    Rothgeb, Matt

    2009-01-01

    This slide presentation reviews the NASA/DOD projects to select an alternative to hexavalent chrome in the aerospace industry. The Phase I process of the project performed: (1) Evaluation and testing of non-chromated coating systems as replacements for hexavalent chrome coatings in aircraft and aerospace applications. (2) Testing of coating systems to DoD and NASA specifications for corrosion resistance and adhesion. (3) Bare corrosion resistance and atmospheric exposure will be focus areas of Phase II Testing. The description includes a chart that summarizes the 3000 hour salt fog test results. The second phase of the project includes (1) Evaluation and testing of coating systems that do not contain hexavalent chrome as replacements for aerospace applications. (2) Evaluation of coatings at Beach Test Site and Launch Complex 39B (3) Evaluation of non-chrome coatings for electronic housings (bare corrosion resistance and electrical impedance) is a part of this round of testing. This project was performed for the Technology Evaluation for Environmental Risk Mitigation (TEERM)

  20. Listening to the beat of a 400 solar-mass, middle-weight black hole

    NASA Astrophysics Data System (ADS)

    Pasham, Dheeraj R.; Strohmayer, Tod E.; Mushotzky, Richard

    2015-01-01

    Accreting X-ray point sources with luminosities exceeding the Eddington limit of a 20 solar mass black hole are referred to as ultraluminous X-ray sources. The brightest of these have long been suspected to host intermediate-mass black holes (mass range of a few 100-1000 solar masses). On such object is M82 X-1, thought to be an intermediate-mass black hole because of its extremely high X-ray luminosity and variability characteristics, although some models suggested that its mass may be only of the order of 20 solar masses. The previous mass estimates were based on scaling relations which used low-frequency characteristic timescales which have large intrinsic uncertainties. In stellar-mass black holes we know that the high frequency quasi-periodic oscillations that occur in a 3:2 frequency ratio (100-450 Hz) are stable and scale inversely with black hole mass with a reasonably small dispersion. The discovery of such stable oscillations thus potentially offers an alternative and less ambiguous mass determination for intermediate-mass black holes, but has hitherto not been realized. I will discuss the discovery of stable, twin-peak (3:2 frequency ratio) X-ray quasi-periodic oscillations from M82 X-1 at the frequencies of 3.32 Hz and 5.07 Hz and how this helps overcome the systematic uncertainties present in previous studies. Assuming we can extend the stellar-mass relationship, I estimate its black hole mass to be 428+-105 solar masses. This work was recently published in Nature (DOI:10.1038/nature13710). I will also discuss future prospects of detecting more of such oscillations to weigh other intermediate-mass black hole candidates.

  1. A 17-billion-solar-mass black hole in a group galaxy with a diffuse core.

    PubMed

    Thomas, Jens; Ma, Chung-Pei; McConnell, Nicholas J; Greene, Jenny E; Blakeslee, John P; Janish, Ryan

    2016-04-21

    Quasars are associated with and powered by the accretion of material onto massive black holes; the detection of highly luminous quasars with redshifts greater than z = 6 suggests that black holes of up to ten billion solar masses already existed 13 billion years ago. Two possible present-day 'dormant' descendants of this population of 'active' black holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres of the Leo and Coma galaxy clusters, which together form the central region of the Great Wall--the largest local structure of galaxies. The most luminous quasars, however, are not confined to such high-density regions of the early Universe; yet dormant black holes of this high mass have not yet been found outside of modern-day rich clusters. Here we report observations of the stellar velocity distribution in the galaxy NGC 1600--a relatively isolated elliptical galaxy near the centre of a galaxy group at a distance of 64 megaparsecs from Earth. We use orbit superposition models to determine that the black hole at the centre of NGC 1600 has a mass of 17 billion solar masses. The spatial distribution of stars near the centre of NGC 1600 is rather diffuse. We find that the region of depleted stellar density in the cores of massive elliptical galaxies extends over the same radius as the gravitational sphere of influence of the central black holes, and interpret this as the dynamical imprint of the black holes. PMID:27049949

  2. A 17-billion-solar-mass black hole in a group galaxy with a diffuse core.

    PubMed

    Thomas, Jens; Ma, Chung-Pei; McConnell, Nicholas J; Greene, Jenny E; Blakeslee, John P; Janish, Ryan

    2016-04-21

    Quasars are associated with and powered by the accretion of material onto massive black holes; the detection of highly luminous quasars with redshifts greater than z = 6 suggests that black holes of up to ten billion solar masses already existed 13 billion years ago. Two possible present-day 'dormant' descendants of this population of 'active' black holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres of the Leo and Coma galaxy clusters, which together form the central region of the Great Wall--the largest local structure of galaxies. The most luminous quasars, however, are not confined to such high-density regions of the early Universe; yet dormant black holes of this high mass have not yet been found outside of modern-day rich clusters. Here we report observations of the stellar velocity distribution in the galaxy NGC 1600--a relatively isolated elliptical galaxy near the centre of a galaxy group at a distance of 64 megaparsecs from Earth. We use orbit superposition models to determine that the black hole at the centre of NGC 1600 has a mass of 17 billion solar masses. The spatial distribution of stars near the centre of NGC 1600 is rather diffuse. We find that the region of depleted stellar density in the cores of massive elliptical galaxies extends over the same radius as the gravitational sphere of influence of the central black holes, and interpret this as the dynamical imprint of the black holes.

  3. NASA TEERM Hexavalent Chrome Alternatives Projects

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt; Rothgeb, Matt

    2011-01-01

    This slide presentation reviews the NASA project to select an alternative to hexavalent chrome in the aerospace industry. Included is a recent historic testing and research that the Agency has performed on (1) the external tank, (2) the shuttle orbiter, (3) the Shuttle Rocket Booster, and (4) the Space Shuttle Main Engine. Other related Technology Evaluation for Environmental Risk Mitigation (TEERM) projects are reviewed. The Phase I process of the project performed testing of alternatives the results are shown in a chart for different coating systems. International collaboration was also reviewed. Phase II involves further testing of pretreatment and primers for 6 and 12 months of exposure to conditions at Launch Pad and the beach. Further test were performed to characterize the life cycle corrosion of the space vehicles. A new task is described as a joint project with the Department of Defense to identify a Hex Chrome Free Coatings for Electronics.

  4. A 400-solar-mass black hole in the galaxy M82.

    PubMed

    Pasham, Dheeraj R; Strohmayer, Tod E; Mushotzky, Richard F

    2014-09-01

    M82 X-1, the brightest X-ray source in the galaxy M82, has been thought to be an intermediate-mass black hole (100 to 10,000 solar masses) because of its extremely high luminosity and variability characteristics, although some models suggest that its mass may be only about 20 solar masses. The previous mass estimates were based on scaling relations that use low-frequency characteristic timescales which have large intrinsic uncertainties. For stellar-mass black holes, we know that the high-frequency quasi-periodic oscillations (100-450 hertz) in the X-ray emission that occur in a 3:2 frequency ratio are stable and scale in frequency inversely with black hole mass with a reasonably small dispersion. The discovery of such stable oscillations thus potentially offers an alternative and less ambiguous means of mass determination for intermediate-mass black holes, but has hitherto not been realized. Here we report stable, twin-peak (3:2 frequency ratio) X-ray quasi-periodic oscillations from M82 X-1 at frequencies of 3.32 ± 0.06 hertz and 5.07 ± 0.06 hertz. Assuming that we can extrapolate the inverse-mass scaling that holds for stellar-mass black holes, we estimate the black hole mass of M82 X-1 to be 428 ± 105 solar masses. In addition, we can estimate the mass using the relativistic precession model, from which we get a value of 415 ± 63 solar masses. PMID:25132552

  5. A 400-solar-mass black hole in the galaxy M82.

    PubMed

    Pasham, Dheeraj R; Strohmayer, Tod E; Mushotzky, Richard F

    2014-09-01

    M82 X-1, the brightest X-ray source in the galaxy M82, has been thought to be an intermediate-mass black hole (100 to 10,000 solar masses) because of its extremely high luminosity and variability characteristics, although some models suggest that its mass may be only about 20 solar masses. The previous mass estimates were based on scaling relations that use low-frequency characteristic timescales which have large intrinsic uncertainties. For stellar-mass black holes, we know that the high-frequency quasi-periodic oscillations (100-450 hertz) in the X-ray emission that occur in a 3:2 frequency ratio are stable and scale in frequency inversely with black hole mass with a reasonably small dispersion. The discovery of such stable oscillations thus potentially offers an alternative and less ambiguous means of mass determination for intermediate-mass black holes, but has hitherto not been realized. Here we report stable, twin-peak (3:2 frequency ratio) X-ray quasi-periodic oscillations from M82 X-1 at frequencies of 3.32 ± 0.06 hertz and 5.07 ± 0.06 hertz. Assuming that we can extrapolate the inverse-mass scaling that holds for stellar-mass black holes, we estimate the black hole mass of M82 X-1 to be 428 ± 105 solar masses. In addition, we can estimate the mass using the relativistic precession model, from which we get a value of 415 ± 63 solar masses.

  6. Improvement of black nickel coatings. [product development for use in solar collectors

    NASA Technical Reports Server (NTRS)

    Peterson, R. E.; Lin, J. H.

    1976-01-01

    Selectively absorbing black nickel coatings are among the most optically efficient low cost coatings for use on flat plate solar collectors. However, a current Ni-Zn-S-O coating in use is quite susceptible to a humid environment, degrading badly in less than ten days at 38 C (100 F) at 95 percent relative humidity. Therefore, a black nickel formula was developed which can withstand such exposures with no loss of optical efficiency, solar absorption of 0.92 and an infrared emittance (at 100 C) of 1.00 were still present after 14 days of humidity exposure. This compares to a solar absorptance of only 0.72 for the previous formula after a similar time period. The electroplating bath and conditions were changed to obtain the more stable coating configuration. The effect of bath composition, temperature, pH, and plating current density and time on the coating composition, spectral optical properties and durability were investigated systematically.

  7. Ultrasound assisted chrome tanning: Towards a clean leather production technology.

    PubMed

    Mengistie, Embialle; Smets, Ilse; Van Gerven, Tom

    2016-09-01

    Nowadays, there is a growing demand for a cleaner, but still effective alternative for production processes like in the leather industry. Ultrasound (US) assisted processing of leather might be promising in this sense. In the present paper, the use of US in the conventional chrome tanning process has been studied at different pH, temperature, tanning time, chrome dose and US exposure time by exposing the skin before tanning and during tanning operation. Both prior exposure of the skin to US and US during tanning improves the chrome uptake and reduces the shrinkage significantly. Prior exposure of the skin to US increase the chrome uptake by 13.8% or reduces the chrome dose from 8% to 5% (% based on skin weight) and shorten the process time by half while US during tanning increases the chrome uptake by 28.5% or reduces the chrome dose from 8% to 4% (half) and the tanning time to one third compared to the control without US. Concomitantly, the resulting leather quality (measured as skin shrinkage) improved from 5.2% to 3.2% shrinkage in the skin exposed to US prior tanning and to 1.3% in the skin exposed to US during the tanning experiment. This study confirms that US chrome tanning is an effective and eco-friendly tanning process which can produce a better quality leather product in a shorter process time with a lower chromium dose.

  8. Hexavalent Chrome Free Coatings for Electronics Applications: Joint Test Report

    NASA Technical Reports Server (NTRS)

    Rothgeb, Matt; Kessel, Kurt

    2013-01-01

    The overall objective of the Hexavalent Chrome Free Coatings for Electronics Applications project is to evaluate and test pretreatments not containing hexavalent chrome in avionics and electronics housing applications. This objective will be accomplished by testing strong performing coating systems from prior NASA and DoD testing or new coating systems as determined by the stakeholders.

  9. A 17-billion-solar-mass black hole in a group galaxy with a diffuse core

    NASA Astrophysics Data System (ADS)

    Thomas, Jens; Ma, Chung-Pei; McConnell, Nicholas J.; Greene, Jenny E.; Blakeslee, John P.; Janish, Ryan

    2016-04-01

    Quasars are associated with and powered by the accretion of material onto massive black holes; the detection of highly luminous quasars with redshifts greater than z = 6 suggests that black holes of up to ten billion solar masses already existed 13 billion years ago. Two possible present-day ‘dormant’ descendants of this population of ‘active’ black holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres of the Leo and Coma galaxy clusters, which together form the central region of the Great Wall—the largest local structure of galaxies. The most luminous quasars, however, are not confined to such high-density regions of the early Universe; yet dormant black holes of this high mass have not yet been found outside of modern-day rich clusters. Here we report observations of the stellar velocity distribution in the galaxy NGC 1600—a relatively isolated elliptical galaxy near the centre of a galaxy group at a distance of 64 megaparsecs from Earth. We use orbit superposition models to determine that the black hole at the centre of NGC 1600 has a mass of 17 billion solar masses. The spatial distribution of stars near the centre of NGC 1600 is rather diffuse. We find that the region of depleted stellar density in the cores of massive elliptical galaxies extends over the same radius as the gravitational sphere of influence of the central black holes, and interpret this as the dynamical imprint of the black holes.

  10. NASA TEERM Hexavalent Chrome Alternatives Projects

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.; Rothgeb, Matthew

    2011-01-01

    The overall objective of the Hex Chrome Free Coatings for Electronics project is to evaluate and test pretreatment coating systems not containing hexavalent chrome in avionics and electronics housing applications. This objective will be accomplished by testing strong performing coating systems from prior NASA and DoD testing or new coating systems as determined by the stakeholders. The technical stakeholders have agreed that this protocol will focus specifically on Class 3 coatings. Original Equipment Manufacturers (OEMs), depots, and support contractors have to be prepared to deal with an electronics supply chain that increasingly provides parts with lead-free finishes, some labeled no differently and intermingled with their SnPb counterparts. Allowance of lead-free components presents one of the greatest risks to the reliability of military and aerospace electronics. The introduction of components with lead-free terminations, termination finishes, or circuit boards presents a host of concerns to customers, suppliers, and maintainers of aerospace and military electronic systems such as: 1. Electrical shorting due to tin whiskers 2. Incompatibility of lead-free processes and parameters (including higher melting points of lead-free alloys) with other materials in the system 3. Unknown material properties and incompatibilities that could reduce solder joint reliability

  11. Solar Hot Water Heater

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The solar panels pictured below, mounted on a Moscow, Idaho home, are part of a domestic hot water heating system capable of providing up to 100 percent of home or small business hot water needs. Produced by Lennox Industries Inc., Marshalltown, Iowa, the panels are commercial versions of a collector co-developed by NASA. In an effort to conserve energy, NASA has installed solar collectors at a number of its own facilities and is conducting research to develop the most efficient systems. Lewis Research Center teamed with Honeywell Inc., Minneapolis, Minnesota to develop the flat plate collector shown. Key to the collector's efficiency is black chrome coating on the plate developed for use on spacecraft solar cells, the coating prevents sun heat from "reradiating," or escaping outward. The design proved the most effective heat absorber among 23 different types of collectors evaluated in a Lewis test program. The Lennox solar domestic hot water heating system has three main components: the array of collectors, a "solar module" (blue unit pictured) and a conventional water heater. A fluid-ethylene glycol and water-is circulated through the collectors to absorb solar heat. The fluid is then piped to a double-walled jacket around a water tank within the solar module.

  12. Antireflection and SiO2 Surface Passivation by Liquid-Phase Chemistry for Efficient Black Silicon Solar Cells: Preprint

    SciTech Connect

    Yuan, H. C.; Oh, J.; Zhang, Y.; Kuznetsov, O. A.; Flood, D. J.; Branz, H. M.

    2012-06-01

    We report solar cells with both black Si antireflection and SiO2 surface passivation provided by inexpensive liquid-phase chemistry, rather than by conventional vacuum-based techniques. Preliminary cell efficiency has reached 16.4%. Nanoporous black Si antireflection on crystalline Si by aqueous etching promises low surface reflection for high photon utilization, together with lower manufacturing cost compared to vacuum-based antireflection coating. Ag-nanoparticle-assisted black Si etching and post-etching chemical treatment recently developed at NREL enables excellent control over the pore diameter and pore separation. Performance of black Si solar cells, including open-circuit voltage, short-circuit current density, and blue response, has benefited from these improvements. Prior to this study, our black Si solar cells were all passivated by thermal SiO2 produced in tube furnaces. Although this passivation is effective, it is not yet ideal for ultra-low-cost manufacturing. In this study, we report, for the first time, the integration of black Si with a proprietary liquid-phase deposition (LPD) passivation from Natcore Technology. The Natcore LPD forms a layer of <10-nm SiO2 on top of the black Si surface in a relatively mild chemical bath at room temperature. We demonstrate black Si solar cells with LPD SiO2 with a spectrum-weighted average reflection lower than 5%, similar to the more costly thermally grown SiO2 approach. However, LPD SiO2 provides somewhat better surface-passivation quality according to the lifetime analysis by the photo-conductivity decay measurement. Moreover, black Si solar cells with LPD SiO2 passivation exhibit higher spectral response at short wavelength compared to those passivated by thermally grown SiO2. With further optimization, the combination of aqueous black Si etching and LPD could provide a pathway for low-cost, high-efficiency crystalline Si solar cells.

  13. Efficient Black Silicon Solar Cells with Multi-Scale Surface Texture

    NASA Astrophysics Data System (ADS)

    Toor, Fatima; Nemeth, William; Page, Matthew; Wang, Qi; Branz, Howard; Yuan, Hao-Chih

    2011-03-01

    A nanostructured, density-graded surface layer can replace conventional quarter-wavelength coatings as the anti-reflection layer in photovoltaics. If the layer is comprised of structures smaller than the wavelength of the incident light and the density is graded across more than about half the wavelength of the light, reflection is strongly suppressed (H. M. Branz et al., APL {94} 2009). We developed an inexpensive liquid etch technique for silicon to produce ``black Si'' based upon this physics. However, the problem of high carrier recombination within this nanostructured layer must be overcome to improve beyond the present best solar cell with its confirmed 16.8% black silicon sunlight-to-electricity conversion efficiency (H-C. Yuan et al., APL {95} 2009). In this work, we combine the black Si layer with conventional KOH-etched pyramidal surface texture (Y. Xiu et al., Langmuir {24 }2008) at micron-scale. Pyramids contribute anti-reflection based on geometric optics. Combining the pyramids with nanostructures only 100 nm deep provides reflectivity below 2% across a wavelength range from 350 - 1000 nm. To-date, we have obtained a solar cell efficiency of 17% with a Voc of 613 mV, Jsc of 35 mA/cm2 and fill-factor of 78%. These cells have improved blue response compared to the best planar black Si cells.

  14. Comparison under a simulated sun of two black-nickel-coated flat-plate solar collectors with a nonselective black-paint-coated collector

    NASA Technical Reports Server (NTRS)

    Simon, F. F.

    1975-01-01

    A performance evaluation was made of two, black nickel coated, flat plate solar collectors. Collector performance was determined under a simulated sun for a wide range of inlet temperatures, including the temperature required for solar powered absorption air conditioning. For a basis of comparison a performance test was made on a traditional, two glass, nonselective, black paint coated, flat plate collector. Performance curves and performance parameters are presented to point out the importance of the design variables which determine an efficient collector. A black nickel coated collector was found to be a good performer at the conditions expected for solar powered absorption air conditioning. This collector attained a thermal efficiency of 50 percent at an inlet temperature of 366 K (200 F) and an incident flux of 946 watts/sq m (300 Btu/hr-sq ft).

  15. The effects of solar radiation and black body re-radiation on thermal comfort.

    PubMed

    Hodder, Simon; Parsons, Ken

    2008-04-01

    When the sun shines on people in enclosed spaces, such as in buildings or vehicles, it directly affects thermal comfort. There is also an indirect effect as surrounding surfaces are heated exposing a person to re-radiation. This laboratory study investigated the effects of long wave re-radiation on thermal comfort, individually and when combined with direct solar radiation. Nine male participants (26.0 +/- 4.7 years) took part in three experimental sessions where they were exposed to radiation from a hot black panel heated to 100 degrees C; direct simulated solar radiation of 600 Wm(-2) and the combined simulated solar radiation and black panel radiation. Exposures were for 30 min, during which subjective responses and mean skin temperatures were recorded. The results showed that, at a surface temperature of 100 degrees C (close to maximum in practice), radiation from the flat black panel provided thermal discomfort but that this was relatively small when compared with the effects of direct solar radiation. It was concluded that re-radiation, from a dashboard in a vehicle, for example, will not have a major direct influence on thermal comfort and that existing models of thermal comfort do not require a specific modification. These results showed that, for the conditions investigated, the addition of re-radiation from internal components has an effect on thermal sensation when combined with direct solar radiation. However, it is not considered that it will be a major factor in a real world situation. This is because, in practice, dashboards are unlikely to maintain very high surface temperatures in vehicles without an unacceptably high air temperature. This study quantifies the contribution of short- and long-wave radiation to thermal comfort. The results will aid vehicle designers to have a better understanding of the complex radiation environment. These include direct radiation from the sun as well as re-radiation from the dashboard and other internal surfaces

  16. The effects of solar radiation and black body re-radiation on thermal comfort.

    PubMed

    Hodder, Simon; Parsons, Ken

    2008-04-01

    When the sun shines on people in enclosed spaces, such as in buildings or vehicles, it directly affects thermal comfort. There is also an indirect effect as surrounding surfaces are heated exposing a person to re-radiation. This laboratory study investigated the effects of long wave re-radiation on thermal comfort, individually and when combined with direct solar radiation. Nine male participants (26.0 +/- 4.7 years) took part in three experimental sessions where they were exposed to radiation from a hot black panel heated to 100 degrees C; direct simulated solar radiation of 600 Wm(-2) and the combined simulated solar radiation and black panel radiation. Exposures were for 30 min, during which subjective responses and mean skin temperatures were recorded. The results showed that, at a surface temperature of 100 degrees C (close to maximum in practice), radiation from the flat black panel provided thermal discomfort but that this was relatively small when compared with the effects of direct solar radiation. It was concluded that re-radiation, from a dashboard in a vehicle, for example, will not have a major direct influence on thermal comfort and that existing models of thermal comfort do not require a specific modification. These results showed that, for the conditions investigated, the addition of re-radiation from internal components has an effect on thermal sensation when combined with direct solar radiation. However, it is not considered that it will be a major factor in a real world situation. This is because, in practice, dashboards are unlikely to maintain very high surface temperatures in vehicles without an unacceptably high air temperature. This study quantifies the contribution of short- and long-wave radiation to thermal comfort. The results will aid vehicle designers to have a better understanding of the complex radiation environment. These include direct radiation from the sun as well as re-radiation from the dashboard and other internal surfaces.

  17. Preliminary study of a solar selective coating system using black cobalt oxide for high temperature solar collectors

    NASA Technical Reports Server (NTRS)

    Mcdonald, G.

    1980-01-01

    Black cobalt oxide coatings were deposited on thin layers of silver or gold which had been deposited on oxidized stainless steel substrates. The reflectance properties of these coatings were measured at various thicknesses of cobalt oxide for integrated values of the solar and infrared spectrum. The values of absorptance and emittance were calculated from the measured reflectance values before and after exposure in air at 650 C for 1000 hours. Also, these cobalt oxide/noble metal/oxide diffusion barrier coatings have absorptances greater than 0.90 and emittances of approximately 0.20 even after about 1000 hours at 650 C.

  18. Quality Improvement of Chrome-Diamond Coatings on Flowing Chrome Plating

    NASA Astrophysics Data System (ADS)

    Belyaev, V. N.; Koslyuk, A. Yu; Lobunets, A. V.; Andreyev, A. S.

    2016-04-01

    The research results of the process of flowing chrome plating of internal surfaces of long-length cylindrical articles with the usage of electrolyte with ultra-dispersed diamonds when continuous article rotation, while chromium-plating, are presented. During experiments the following varying technological parameters: electrolyte temperature and article frequency rotation were chosen, and experimental samples were obtained. Estimation of porosity, micro-hardness, thickness of chrome coatings and uniformity were performed as well as the precipitation structure by the method of scanning electron microscopy. The results showed that the use of ultra-dispersed diamonds and realization of the scheme with rotation of detail-cathode when flowing chromium-plating allows one to increase servicing characteristics of the coating due to the decrease of grains size of chrome coating and porosity, and due to the increase of micro-hardness, so confirming the efficiency of using the suggested scheme of coating application and the given type of ultra-dispersed fillers when chromium-plating.

  19. Preliminary study of a solar selective coating system using black cobalt oxide for high temperature solar collectors

    NASA Technical Reports Server (NTRS)

    Mcdonald, G.

    1980-01-01

    Black cobalt oxide coatings (high solar absorptance layer) were deposited on thin layers of silver or gold (low emittance layer) which had been previously deposited on oxidized (diffusion barrier layer) stainless steel substrates. The reflectance properties of these coatings were measured at various thicknesses of cobalt for integrated values of the solar and infrared spectrum. The values of absorptance and emittance were calculated from the measured reflectance values, before and after exposure in air at 650 C for approximately 1000 hours. Absorptance and emittance were interdependent functions of the weight of cobalt oxide. Also, these cobalt oxide/noble metal/oxide diffusion barrier coatings have absorptances greater than 0.90 and emittances of approximately 0.20 even after about 1000 hours at 650 C.

  20. Structural and optical properties of copper-coated substrates for solar thermal absorbers

    NASA Astrophysics Data System (ADS)

    Pratesi, Stefano; De Lucia, Maurizio; Meucci, Marco; Sani, Elisa

    2016-10-01

    Spectral selectivity, i.e. merging a high absorbance at sunlight wavelengths to a low emittance at the wavelengths of thermal spectrum, is a key characteristics for materials to be used for solar thermal receivers. It is known that spectrally selective absorbers can raise the receiver efficiency for all solar thermal technologies. Tubular sunlight receivers for parabolic trough collector (PTC) systems can be improved by the use of spectrally selective coatings. Their absorbance is increased by deposing black films, while the thermal emittance is minimized by the use of properly-prepared substrates. In this work we describe the intermediate step in the fabrication of black-chrome coated solar absorbers, namely the fabrication and characterization of copper coatings on previously nickel-plated stainless steel substrates. We investigate the copper surface features and optical properties, correlating them to the coating thickness and to the deposition process, in the perspective to assess optimal conditions for solar absorber applications.

  1. Molecular spectroscopic study for suggested mechanism of chrome tanned leather

    NASA Astrophysics Data System (ADS)

    Nashy, Elshahat H. A.; Osman, Osama; Mahmoud, Abdel Aziz; Ibrahim, Medhat

    2012-03-01

    Collagen represents the structural protein of the extracellular matrix, which gives strength of hides and/or skin under tanning process. Chrome tan is the most important tanning agent all over the world. The methods for production of leather evolved over several centuries as art and engineering with little understanding of the underlying science. The present work is devoted to suggest the most probable mechanistic action of chrome tan on hide proteins. First the affect of Cr upon hide protein is indicated by the studied mechanical properties. Then the spectroscopic characterization of the hide protein as well as chrome tanned leather was carried out with Horizontal Attenuated Total Reflection (HATR) FT-IR. The obtained results indicate how the chromium can attached with the active sites of collagen. Molecular modeling confirms that chromium can react with amino as well as carboxylate groups. Four schemes were obtained to describe the possible interactions of chrome tan with hide proteins.

  2. CAPSULE REPORT: HARD CHROME FUME SUPPRESSANTS & CONTROL TECHNOLOGIES

    EPA Science Inventory

    All existing information which includes the information extrapolated from the Hard Chrome Pollution Prevention Demonstration Project(s) and other sources derived from plating facilities and industry contacts, will be condensed and featured in this document. At least five chromium...

  3. LABORATORY STUDY FOR THE REDUCTION OF CHROME (VI) TO CHROME (III) USING SODIUM METABISULFITE UNDER ACIDIC CONDITIONS

    SciTech Connect

    DUNCAM JB; GUTHRIE MD; LUECK KJ; AVILA M

    2007-07-18

    This report describes the results from RPP-PLAN-32738, 'Test Plan for the Effluent Treatment Facility to Reduce Chrome(VI) to Chrome(I1I) in the Secondary Waste Stream', using sodium metabisulfite. Appendix A presents the report as submitted by the Center for Laboratory Sciences (CLS) to CH2M HILL Hanford Group, Inc. The CLS carried out the laboratory effort under Contract Number 21065, release Number 30. This report extracts the more pertinent aspects of the laboratory effort.

  4. Flexible thin-film black gold membranes with ultrabroadband plasmonic nanofocusing for efficient solar vapour generation.

    PubMed

    Bae, Kyuyoung; Kang, Gumin; Cho, Suehyun K; Park, Wounjhang; Kim, Kyoungsik; Padilla, Willie J

    2015-12-14

    Solar steam generation has been achieved by surface plasmon heating with metallic nanoshells or nanoparticles, which have inherently narrow absorption bandwidth. For efficient light-to-heat conversion from a wider solar spectrum, we employ adiabatic plasmonic nanofocusing to attain both polarization-independent ultrabroadband light absorption and high plasmon dissipation loss. Here we demonstrate large area, flexible thin-film black gold membranes, which have multiscale structures of varying metallic nanoscale gaps (0-200 nm) as well as microscale funnel structures. The adiabatic nanofocusing of self-aggregated metallic nanowire bundle arrays produces average absorption of 91% at 400-2,500 nm and the microscale funnel structures lead to average reflection of 7% at 2.5-17 μm. This membrane allows heat localization within the few micrometre-thick layer and continuous water provision through micropores. We efficiently generate water vapour with solar thermal conversion efficiency up to 57% at 20 kW m(-2). This new structure has a variety of applications in solar energy harvesting, thermoplasmonics and related technologies.

  5. Flexible thin-film black gold membranes with ultrabroadband plasmonic nanofocusing for efficient solar vapour generation.

    PubMed

    Bae, Kyuyoung; Kang, Gumin; Cho, Suehyun K; Park, Wounjhang; Kim, Kyoungsik; Padilla, Willie J

    2015-01-01

    Solar steam generation has been achieved by surface plasmon heating with metallic nanoshells or nanoparticles, which have inherently narrow absorption bandwidth. For efficient light-to-heat conversion from a wider solar spectrum, we employ adiabatic plasmonic nanofocusing to attain both polarization-independent ultrabroadband light absorption and high plasmon dissipation loss. Here we demonstrate large area, flexible thin-film black gold membranes, which have multiscale structures of varying metallic nanoscale gaps (0-200 nm) as well as microscale funnel structures. The adiabatic nanofocusing of self-aggregated metallic nanowire bundle arrays produces average absorption of 91% at 400-2,500 nm and the microscale funnel structures lead to average reflection of 7% at 2.5-17 μm. This membrane allows heat localization within the few micrometre-thick layer and continuous water provision through micropores. We efficiently generate water vapour with solar thermal conversion efficiency up to 57% at 20 kW m(-2). This new structure has a variety of applications in solar energy harvesting, thermoplasmonics and related technologies. PMID:26657535

  6. Flexible thin-film black gold membranes with ultrabroadband plasmonic nanofocusing for efficient solar vapour generation

    PubMed Central

    Bae, Kyuyoung; Kang, Gumin; Cho, Suehyun K.; Park, Wounjhang; Kim, Kyoungsik; Padilla, Willie J.

    2015-01-01

    Solar steam generation has been achieved by surface plasmon heating with metallic nanoshells or nanoparticles, which have inherently narrow absorption bandwidth. For efficient light-to-heat conversion from a wider solar spectrum, we employ adiabatic plasmonic nanofocusing to attain both polarization-independent ultrabroadband light absorption and high plasmon dissipation loss. Here we demonstrate large area, flexible thin-film black gold membranes, which have multiscale structures of varying metallic nanoscale gaps (0–200 nm) as well as microscale funnel structures. The adiabatic nanofocusing of self-aggregated metallic nanowire bundle arrays produces average absorption of 91% at 400–2,500 nm and the microscale funnel structures lead to average reflection of 7% at 2.5–17 μm. This membrane allows heat localization within the few micrometre-thick layer and continuous water provision through micropores. We efficiently generate water vapour with solar thermal conversion efficiency up to 57% at 20 kW m−2. This new structure has a variety of applications in solar energy harvesting, thermoplasmonics and related technologies. PMID:26657535

  7. GSDO Program Hexavalent Chrome Alternatives: Final Pretreatments Test Report

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2013-01-01

    Hexavalent chrome free pretreatments should be considered for use on Ground Support Equipment (OSE) and Electrical Ground Support Equipment (EOSE). Both of the hexavalent chrome free pretreatments (Metalast TCP HF and SurTec 650C) evaluated by this project met, and in some instances exceeded, the requirements ofMIL-DTL-5541 "Chemical Conversion Coatings on Aluminum and Aluminum Alloys". For DC resistance measurements, both Metalast TCP HF and SurTec (!50C met initial requirements following assembly and in many cases continued to maintain passing readings for the duration of testing.

  8. 40 CFR 415.340 - Applicability; description of the chrome pigments production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... chrome pigments production subcategory. 415.340 Section 415.340 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Chrome Pigments Production Subcategory § 415.340 Applicability; description of the chrome pigments production subcategory. This subpart applies to discharges to waters of the United States...

  9. 40 CFR 415.340 - Applicability; description of the chrome pigments production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... chrome pigments production subcategory. 415.340 Section 415.340 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Chrome Pigments Production Subcategory § 415.340 Applicability; description of the chrome pigments production subcategory. This subpart applies to discharges to waters of the United States...

  10. 40 CFR 415.340 - Applicability; description of the chrome pigments production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... chrome pigments production subcategory. 415.340 Section 415.340 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Chrome Pigments Production Subcategory § 415.340 Applicability; description of the chrome pigments production subcategory. This subpart applies to discharges to waters of the United States...

  11. 40 CFR 415.340 - Applicability; description of the chrome pigments production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... chrome pigments production subcategory. 415.340 Section 415.340 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Chrome Pigments Production Subcategory § 415.340 Applicability; description of the chrome pigments production subcategory. This subpart applies to discharges to waters of the United States...

  12. 40 CFR 415.340 - Applicability; description of the chrome pigments production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... chrome pigments production subcategory. 415.340 Section 415.340 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Chrome Pigments Production Subcategory § 415.340 Applicability; description of the chrome pigments production subcategory. This subpart applies to discharges to waters of the United States...

  13. Efficient black silicon solar cell with a density-graded nanoporous surface: Optical properties, performance limitations, and design rules

    NASA Astrophysics Data System (ADS)

    Yuan, Hao-Chih; Yost, Vernon E.; Page, Matthew R.; Stradins, Paul; Meier, Daniel L.; Branz, Howard M.

    2009-09-01

    We study optical effects and factors limiting performance of our confirmed 16.8% efficiency "black silicon" solar cells. The cells incorporate density-graded nanoporous surface layers made by a one-step nanoparticle-catalyzed etch and reflect less than 3% of the solar spectrum, with no conventional antireflection coating. The cells are limited by recombination in the nanoporous layer which decreases short-wavelength spectral response. The optimum density-graded layer depth is then a compromise between reflectance reduction and recombination loss. Finally, we propose universal design rules for high-efficiency solar cells based on density-graded surfaces.

  14. Black silicon solar cell: analysis optimization and evolution towards a thinner and flexible future

    NASA Astrophysics Data System (ADS)

    Bardhan Roy, Arijit; Dhar, Arup; Choudhuri, Mrinmoyee; Das, Sonali; Minhaz Hossain, S.; Kundu, Avra

    2016-07-01

    Analysis and optimization of silicon nano-structured geometry (black silicon) for photovoltaic applications has been reported. It is seen that a unique class of geometry: micro-nanostructure has the potential to find a balance between the conflicting interests of reduced reflection for wide angles of incidence, reduced surface area enhancement due to the nano-structuring of the substrate and reduced material wastage due to the etching of the silicon substrate to realize the geometry itself. It is established that even optimally designed micro-nanostructures would not be useful for conventional wafer based approaches. The work presents computational studies on how such micro-nanostructures are more potent for future ultra-thin monocrystalline silicon absorbers. For such ultra-thin absorbers, the optimally designed micro-nanostructures provide additional advantages of advanced light management capabilities as it behaves as a lossy 2D photonic crystal making the physically thin absorber optically thick along with the ability to collect photo-generated carriers orthogonal to the direction of light (radial junction) for unified photon–electron harvesting. Most significantly, the work answers the key question on how thin the monocrystalline solar absorber should be so that optimum micro-nanostructure would be able to harness the incident photons ensuring proper collection so as to reach the well-known Shockley–Queisser limit of solar cells. Flexible ultra-thin monocrystalline silicon solar cells have been fabricated using nanosphere lithography and MacEtch technique along with a synergistic association of crystalline and amorphous silicon technologies to demonstrate its physical and technological flexibilities. The outcomes are relevant so that nanotechnology may be seamlessly integrated into the technology roadmap of monocrystalline silicon solar cells as the silicon thickness should be significantly reduced without compromising the efficiency within the next decade.

  15. Black silicon solar cell: analysis optimization and evolution towards a thinner and flexible future

    NASA Astrophysics Data System (ADS)

    Bardhan Roy, Arijit; Dhar, Arup; Choudhuri, Mrinmoyee; Das, Sonali; Minhaz Hossain, S.; Kundu, Avra

    2016-07-01

    Analysis and optimization of silicon nano-structured geometry (black silicon) for photovoltaic applications has been reported. It is seen that a unique class of geometry: micro-nanostructure has the potential to find a balance between the conflicting interests of reduced reflection for wide angles of incidence, reduced surface area enhancement due to the nano-structuring of the substrate and reduced material wastage due to the etching of the silicon substrate to realize the geometry itself. It is established that even optimally designed micro-nanostructures would not be useful for conventional wafer based approaches. The work presents computational studies on how such micro-nanostructures are more potent for future ultra-thin monocrystalline silicon absorbers. For such ultra-thin absorbers, the optimally designed micro-nanostructures provide additional advantages of advanced light management capabilities as it behaves as a lossy 2D photonic crystal making the physically thin absorber optically thick along with the ability to collect photo-generated carriers orthogonal to the direction of light (radial junction) for unified photon-electron harvesting. Most significantly, the work answers the key question on how thin the monocrystalline solar absorber should be so that optimum micro-nanostructure would be able to harness the incident photons ensuring proper collection so as to reach the well-known Shockley-Queisser limit of solar cells. Flexible ultra-thin monocrystalline silicon solar cells have been fabricated using nanosphere lithography and MacEtch technique along with a synergistic association of crystalline and amorphous silicon technologies to demonstrate its physical and technological flexibilities. The outcomes are relevant so that nanotechnology may be seamlessly integrated into the technology roadmap of monocrystalline silicon solar cells as the silicon thickness should be significantly reduced without compromising the efficiency within the next decade.

  16. Black silicon solar cell: analysis optimization and evolution towards a thinner and flexible future.

    PubMed

    Roy, Arijit Bardhan; Dhar, Arup; Choudhuri, Mrinmoyee; Das, Sonali; Hossain, S Minhaz; Kundu, Avra

    2016-07-29

    Analysis and optimization of silicon nano-structured geometry (black silicon) for photovoltaic applications has been reported. It is seen that a unique class of geometry: micro-nanostructure has the potential to find a balance between the conflicting interests of reduced reflection for wide angles of incidence, reduced surface area enhancement due to the nano-structuring of the substrate and reduced material wastage due to the etching of the silicon substrate to realize the geometry itself. It is established that even optimally designed micro-nanostructures would not be useful for conventional wafer based approaches. The work presents computational studies on how such micro-nanostructures are more potent for future ultra-thin monocrystalline silicon absorbers. For such ultra-thin absorbers, the optimally designed micro-nanostructures provide additional advantages of advanced light management capabilities as it behaves as a lossy 2D photonic crystal making the physically thin absorber optically thick along with the ability to collect photo-generated carriers orthogonal to the direction of light (radial junction) for unified photon-electron harvesting. Most significantly, the work answers the key question on how thin the monocrystalline solar absorber should be so that optimum micro-nanostructure would be able to harness the incident photons ensuring proper collection so as to reach the well-known Shockley-Queisser limit of solar cells. Flexible ultra-thin monocrystalline silicon solar cells have been fabricated using nanosphere lithography and MacEtch technique along with a synergistic association of crystalline and amorphous silicon technologies to demonstrate its physical and technological flexibilities. The outcomes are relevant so that nanotechnology may be seamlessly integrated into the technology roadmap of monocrystalline silicon solar cells as the silicon thickness should be significantly reduced without compromising the efficiency within the next decade

  17. Black silicon solar cell: analysis optimization and evolution towards a thinner and flexible future.

    PubMed

    Roy, Arijit Bardhan; Dhar, Arup; Choudhuri, Mrinmoyee; Das, Sonali; Hossain, S Minhaz; Kundu, Avra

    2016-07-29

    Analysis and optimization of silicon nano-structured geometry (black silicon) for photovoltaic applications has been reported. It is seen that a unique class of geometry: micro-nanostructure has the potential to find a balance between the conflicting interests of reduced reflection for wide angles of incidence, reduced surface area enhancement due to the nano-structuring of the substrate and reduced material wastage due to the etching of the silicon substrate to realize the geometry itself. It is established that even optimally designed micro-nanostructures would not be useful for conventional wafer based approaches. The work presents computational studies on how such micro-nanostructures are more potent for future ultra-thin monocrystalline silicon absorbers. For such ultra-thin absorbers, the optimally designed micro-nanostructures provide additional advantages of advanced light management capabilities as it behaves as a lossy 2D photonic crystal making the physically thin absorber optically thick along with the ability to collect photo-generated carriers orthogonal to the direction of light (radial junction) for unified photon-electron harvesting. Most significantly, the work answers the key question on how thin the monocrystalline solar absorber should be so that optimum micro-nanostructure would be able to harness the incident photons ensuring proper collection so as to reach the well-known Shockley-Queisser limit of solar cells. Flexible ultra-thin monocrystalline silicon solar cells have been fabricated using nanosphere lithography and MacEtch technique along with a synergistic association of crystalline and amorphous silicon technologies to demonstrate its physical and technological flexibilities. The outcomes are relevant so that nanotechnology may be seamlessly integrated into the technology roadmap of monocrystalline silicon solar cells as the silicon thickness should be significantly reduced without compromising the efficiency within the next decade.

  18. Optical characterization of nanopillar black silicon for plasmonic and Solar cell application

    NASA Astrophysics Data System (ADS)

    Gartia, M. R.; Chen, Y.; Xu, Z.; Bordain, Y. C.; Eichorst, J.; Mabon, J. C.; Soares, J. A. N. de T.; Clegg, R. M.; Liu, G. L.

    2011-10-01

    With the goal of improving photo-absorption of photovoltaic device and for plasmonic application we have fabricated nanopillar black silicon devices through etching-passivation technique which does not require any photomask and whole wafer scale uniformity is achieved at room temperature in a short time. We have carried out thorough optical characterization for nanopillar black silicon devices to be used for solar cell and plasmonic applications. Cathodoluminescence (CL), current dependent CL spectroscopy, photoluminescence (at room temperature and 77 K), Raman spectroscopy, reflectance and absorption measurement have been performed on the device. A thin layer of Ag is deposited to render with plasmonic property and the plasmonic effect is probed using surface plasmon enhanced fluorescence, angle dependent reflectance measurements, high resolution cathodoluminescence (CL), surface enhanced Raman spectroscopy (SERS) measurement and Fluorescence Lifetime Imaging Microscopy (FLIM) experiment. We obtained reduction in optical reflection of ~ 12 times on b-Si substrate from UV to NIR range, the nanostructured fluorescence enhancement of ~40 times and the Raman scattering enhancement factor of 6.4×107.

  19. Influence of black silicon surfaces on the performance of back-contacted back silicon heterojunction solar cells.

    PubMed

    Ziegler, Johannes; Haschke, Jan; Käsebier, Thomas; Korte, Lars; Sprafke, Alexander N; Wehrspohn, Ralf B

    2014-10-20

    The influence of different black silicon (b-Si) front side textures prepared by inductively coupled reactive ion etching (ICP-RIE) on the performance of back-contacted back silicon heterojunction (BCB-SHJ) solar cells is investigated in detail regarding their optical performance, black silicon surface passivation and internal quantum efficiency. Under optimized conditions the effective minority carrier lifetime measured on black silicon surfaces passivated with Al(2)O(3) can be higher than lifetimes measured for the SiO(2)/SiN(x) passivation stack used in the reference cells with standard KOH textures. However, to outperform the electrical current of silicon back-contact cells, the black silicon back-contact cell process needs to be optimized with aspect to chemical and thermal stability of the used dielectric layer combination on the cell.

  20. Chrome induced nasal septal perforation-An occupational hazard.

    PubMed

    Krishna, N Joshi

    2004-04-01

    86 patients, working in a chemical factory dealing with Chrome manufacturing job, were referred by Health Inspectai to F S 1 S Hospital O PD 32 patients out of above were found to be having Nasal septal perforation and were recommended to Medical Board for consideration of compensation as cases of Occupational hazard.

  1. Nanostructured photoelectrochemical solar cell for nitrogen reduction using plasmon-enhanced black silicon.

    PubMed

    Ali, Muataz; Zhou, Fengling; Chen, Kun; Kotzur, Christopher; Xiao, Changlong; Bourgeois, Laure; Zhang, Xinyi; MacFarlane, Douglas R

    2016-04-20

    Ammonia (NH3) is one of the most widely produced chemicals worldwide. It has application in the production of many important chemicals, particularly fertilizers. It is also, potentially, an important energy storage intermediate and clean energy carrier. Ammonia production, however, mostly uses fossil fuels and currently accounts for more than 1.6% of global CO2 emissions (0.57  Gt in 2015). Here we describe a solar-driven nanostructured photoelectrochemical cell based on plasmon-enhanced black silicon for the conversion of atmospheric N2 to ammonia producing yields of 13.3 mg m(-2) h(-1) under 2 suns illumination. The yield increases with pressure; the highest observed in this work was 60 mg m(-2) h(-1) at 7 atm. In the presence of sulfite as a reactant, the process also offers a direct solar energy route to ammonium sulfate, a fertilizer of economic importance. Although the yields are currently not sufficient for practical application, there is much scope for improvement in the active materials in this cell.

  2. Nanostructured photoelectrochemical solar cell for nitrogen reduction using plasmon-enhanced black silicon.

    PubMed

    Ali, Muataz; Zhou, Fengling; Chen, Kun; Kotzur, Christopher; Xiao, Changlong; Bourgeois, Laure; Zhang, Xinyi; MacFarlane, Douglas R

    2016-01-01

    Ammonia (NH3) is one of the most widely produced chemicals worldwide. It has application in the production of many important chemicals, particularly fertilizers. It is also, potentially, an important energy storage intermediate and clean energy carrier. Ammonia production, however, mostly uses fossil fuels and currently accounts for more than 1.6% of global CO2 emissions (0.57  Gt in 2015). Here we describe a solar-driven nanostructured photoelectrochemical cell based on plasmon-enhanced black silicon for the conversion of atmospheric N2 to ammonia producing yields of 13.3 mg m(-2) h(-1) under 2 suns illumination. The yield increases with pressure; the highest observed in this work was 60 mg m(-2) h(-1) at 7 atm. In the presence of sulfite as a reactant, the process also offers a direct solar energy route to ammonium sulfate, a fertilizer of economic importance. Although the yields are currently not sufficient for practical application, there is much scope for improvement in the active materials in this cell. PMID:27093916

  3. Nanostructured photoelectrochemical solar cell for nitrogen reduction using plasmon-enhanced black silicon

    PubMed Central

    Ali, Muataz; Zhou, Fengling; Chen, Kun; Kotzur, Christopher; Xiao, Changlong; Bourgeois, Laure; Zhang, Xinyi; MacFarlane, Douglas R.

    2016-01-01

    Ammonia (NH3) is one of the most widely produced chemicals worldwide. It has application in the production of many important chemicals, particularly fertilizers. It is also, potentially, an important energy storage intermediate and clean energy carrier. Ammonia production, however, mostly uses fossil fuels and currently accounts for more than 1.6% of global CO2 emissions (0.57  Gt in 2015). Here we describe a solar-driven nanostructured photoelectrochemical cell based on plasmon-enhanced black silicon for the conversion of atmospheric N2 to ammonia producing yields of 13.3 mg m−2 h−1 under 2 suns illumination. The yield increases with pressure; the highest observed in this work was 60 mg m−2 h−1 at 7 atm. In the presence of sulfite as a reactant, the process also offers a direct solar energy route to ammonium sulfate, a fertilizer of economic importance. Although the yields are currently not sufficient for practical application, there is much scope for improvement in the active materials in this cell. PMID:27093916

  4. Nanostructured photoelectrochemical solar cell for nitrogen reduction using plasmon-enhanced black silicon

    NASA Astrophysics Data System (ADS)

    Ali, Muataz; Zhou, Fengling; Chen, Kun; Kotzur, Christopher; Xiao, Changlong; Bourgeois, Laure; Zhang, Xinyi; Macfarlane, Douglas R.

    2016-04-01

    Ammonia (NH3) is one of the most widely produced chemicals worldwide. It has application in the production of many important chemicals, particularly fertilizers. It is also, potentially, an important energy storage intermediate and clean energy carrier. Ammonia production, however, mostly uses fossil fuels and currently accounts for more than 1.6% of global CO2 emissions (0.57 Gt in 2015). Here we describe a solar-driven nanostructured photoelectrochemical cell based on plasmon-enhanced black silicon for the conversion of atmospheric N2 to ammonia producing yields of 13.3 mg m-2 h-1 under 2 suns illumination. The yield increases with pressure; the highest observed in this work was 60 mg m-2 h-1 at 7 atm. In the presence of sulfite as a reactant, the process also offers a direct solar energy route to ammonium sulfate, a fertilizer of economic importance. Although the yields are currently not sufficient for practical application, there is much scope for improvement in the active materials in this cell.

  5. 17.1%-Efficient Multi-Scale-Textured Black Silicon Solar Cells without Dielectric Antireflection Coating: Preprint

    SciTech Connect

    Toor, F.; Page, M. R.; Branz, H. M.; Yuan, H. C.

    2011-07-01

    In this work we present 17.1%-efficient p-type single crystal Si solar cells with a multi-scale-textured surface and no dielectric antireflection coating. Multi-scale texturing is achieved by a gold-nanoparticle-assisted nanoporous etch after conventional micron scale KOH-based pyramid texturing (pyramid black etching). By incorporating geometric enhancement of antireflection, this multi-scale texturing reduces the nanoporosity depth required to make silicon 'black' compared to nanoporous planar surfaces. As a result, it improves short-wavelength spectral response (blue response), previously one of the major limiting factors in 'black-Si' solar cells. With multi-scale texturing, the spectrum-weighted average reflectance from 350- to 1000-nm wavelength is below 2% with a 100-nm deep nanoporous layer. In comparison, roughly 250-nm deep nanopores are needed to achieve similar reflectance on planar surface. Here, we characterize surface morphology, reflectivity and solar cell performance of the multi-scale textured solar cells.

  6. Discovery of a 12 billion solar mass black hole at redshift 6.3 and its challenge to the black hole/galaxy co-evolution at cosmic dawn

    NASA Astrophysics Data System (ADS)

    Wu, Xue-Bing; Wang, Feige; Fan, Xiaohui; Yi, Weimin; Zuo, Wenwen; Bian, Fuyan; Jiang, Linhua; McGreer, Ian; Wang, Ran; Yang, Jinyi; Yang, Qian; Thompson, David; Beletsky, Yuri

    2015-08-01

    To date about 40 quasars with redshifts z>6 have been discovered. Each quasar harbors a black hole with a mass of about one billion solar masses. The existence of such black holes when the Universe was less than one billion years after the Big Bang presents significant challenges to theories of the formation and growth of black holes and the black hole/galaxy co-evolution. I will report a recent discovery of an ultra-luminous quasar at redshift z=6.30, which has an observed optical and near-infrared luminosity a few times greater than those of previously known z>6 quasars. With near-infrared spectroscopy, we obtain a black hole mass of about 12 billion solar masses, which is well consistent with the mass derived by assuming an Eddington-limited accretion. This ultra-luminous quasar with a 12 billion solar mass black hole at z>6 provides a unique laboratory to the study of the mass assembly and galaxy formation around the most massive black holes in the early Universe. It raises further challenges to the black hole/galaxy co-evolution in the epoch of cosmic reionization because the black hole needs to grow much faster than the host galaxy.

  7. High Temperature Brush Seal Tuft Testing of Selected Nickel-Chrome and Cobalt-Chrome Superalloys

    NASA Technical Reports Server (NTRS)

    Fellenstein, James A.; DellaCorte, Christopher; Moore, Kenneth D.; Boyes, Esther

    1997-01-01

    The tribology of brush seals is of considerable interest to turbine engine designers because bristle wear continues to limit long term seal performance and life. To provide better materials characterization and foster the development of improved seals, NASA Lewis has developed a brush seal tuft tester. In this test, a 'paintbrush' sample tuft is loaded under constant contact pressure against the outside diameter of a rotating journal. With this configuration, load and friction are directly measured and accurate wear measurements are possible. Previously reported research using this facility showed excellent data repeatability and wear morphology similar to published seal data and dynamic rig tests. This paper is an update of the ongoing research into the tribology of brush seals. The effects of wire materials processing on seal wear and the tribological results for three journal coatings are discussed. Included in the materials processing were two nickel-chrome superalloys each processed to two different yield strengths. The results suggest that seal wear is dependent more on material composition than processing conditions.

  8. Detection of a novel pigment network feature in reticulated black solar lentigo by high-resolution epiluminescence microscopy.

    PubMed

    Haas, Norbert; Hermes, Barbara; Henz, Beate M

    2002-06-01

    Epiluminescence light microscopy (ELM) of pigmented skin lesions has led to a catalog of pigment network (PN) features. The objective of this study was to determine whether high-resolution ELM detects additional pigment structures not seen with conventional ELM. Epiluminescence light microscopy was performed by placing the lens of a standard light microscope directly on the skin surface, with resulting enhanced optical resolution compared with ELM systems currently in general use. Eight reticulated black solar lentigines were studied. All lesions were viewed and analyzed using dermatoscopic criteria for the PN. In addition, they were all photographed, excised, and examined histologically. Two subtypes of black solar lentigines could be distinguished using generally accepted dermatoscopic criteria for the PN. Furthermore, a new pigment structure was detected, namely, pigment spots of equal color, shape, and size, which were regularly superimposed on and juxtaposed to the PN. Clinicopathologic correlation showed these spots to represent individual hyperpigmented corneocytes. Because such cells result from physiologic excessive pigment translocation via the epidermal melanocytic unit, we called them pigmented corneocytes. Pigmented corneocytes were seen in seven of eight black solar lentigines. The ELM technique presented here allows for more detailed analysis and classification of the PN components. Pigmented corneocytes are proposed as an additional dermatoscopic criterion.

  9. Fatigue of alumina-based ceramics and chrome carbide composites

    NASA Astrophysics Data System (ADS)

    Kireitseu, Maksim V.; Yerakhavets, Liudmila; Nemerenco, Ion; Basenuk, Vladimir L.

    2003-10-01

    The paper was revealed a fatigue in the alumina-chrome carbide composite. The trapped crack front resembles a collinear array of microcracks interspersed by grains rich in transformable precipitates. This micromechanical model provides a reasonable explanation for the observed fatigue crack growth. A numerical procedure similar to the one used in the analysis of the array of collinear cracks, based on complex potentials and dislocation formalism is also used to simulate fatigue of composite coatings based on oxide ceramics and chrome carbide. Assuming power-law crack growth, it is found that the crack growth rate decreases with the applied stress intensity factor in the initial stage of fatigue crack growth. Depending on the applied load and the amount of transformation, the growth rate either goes through a minimum before increasing to the normal crack regime, or the rate continues to decrease until the crack is arrested. A detailed parametric study of the phenomenon of fatigue crack arrest in composite coatings based on oxide ceramics and chrome carbide reveals that the combination of transformation strength parameter and applied load determines whether or not crack arrest will occur, irrespective of the initial crack length. Based on the parametric study a simple linear relationship between the applied load and the minimum transformation strength parameter necessary to cause crack arrest has been developed. it will be found useful in the design against fatigue by predicting the maximum toad at which crack arrest can be expected.

  10. An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30.

    PubMed

    Wu, Xue-Bing; Wang, Feige; Fan, Xiaohui; Yi, Weimin; Zuo, Wenwen; Bian, Fuyan; Jiang, Linhua; McGreer, Ian D; Wang, Ran; Yang, Jinyi; Yang, Qian; Thompson, David; Beletsky, Yuri

    2015-02-26

    So far, roughly 40 quasars with redshifts greater than z = 6 have been discovered. Each quasar contains a black hole with a mass of about one billion solar masses (10(9) M Sun symbol). The existence of such black holes when the Universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the coevolution of black holes and galaxies. Here we report the discovery of an ultraluminous quasar, SDSS J010013.02+280225.8, at redshift z = 6.30. It has an optical and near-infrared luminosity a few times greater than those of previously known z > 6 quasars. On the basis of the deep absorption trough on the blue side of the Lyman-α emission line in the spectrum, we estimate the proper size of the ionized proximity zone associated with the quasar to be about 26 million light years, larger than found with other z > 6.1 quasars with lower luminosities. We estimate (on the basis of a near-infrared spectrum) that the black hole has a mass of ∼1.2 × 10(10) M Sun symbol, which is consistent with the 1.3 × 10(10) M Sun symbol derived by assuming an Eddington-limited accretion rate. PMID:25719667

  11. An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30.

    PubMed

    Wu, Xue-Bing; Wang, Feige; Fan, Xiaohui; Yi, Weimin; Zuo, Wenwen; Bian, Fuyan; Jiang, Linhua; McGreer, Ian D; Wang, Ran; Yang, Jinyi; Yang, Qian; Thompson, David; Beletsky, Yuri

    2015-02-26

    So far, roughly 40 quasars with redshifts greater than z = 6 have been discovered. Each quasar contains a black hole with a mass of about one billion solar masses (10(9) M Sun symbol). The existence of such black holes when the Universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the coevolution of black holes and galaxies. Here we report the discovery of an ultraluminous quasar, SDSS J010013.02+280225.8, at redshift z = 6.30. It has an optical and near-infrared luminosity a few times greater than those of previously known z > 6 quasars. On the basis of the deep absorption trough on the blue side of the Lyman-α emission line in the spectrum, we estimate the proper size of the ionized proximity zone associated with the quasar to be about 26 million light years, larger than found with other z > 6.1 quasars with lower luminosities. We estimate (on the basis of a near-infrared spectrum) that the black hole has a mass of ∼1.2 × 10(10) M Sun symbol, which is consistent with the 1.3 × 10(10) M Sun symbol derived by assuming an Eddington-limited accretion rate.

  12. A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source.

    PubMed

    Motch, C; Pakull, M W; Soria, R; Grisé, F; Pietrzyński, G

    2014-10-01

    Most ultraluminous X-ray sources have a typical set of properties not seen in Galactic stellar-mass black holes. They have luminosities of more than 3 × 10(39) ergs per second, unusually soft X-ray components (with a typical temperature of less than about 0.3 kiloelectronvolts) and a characteristic downturn in their spectra above about 5 kiloelectronvolts. Such puzzling properties have been interpreted either as evidence of intermediate-mass black holes or as emission from stellar-mass black holes accreting above their Eddington limit, analogous to some Galactic black holes at peak luminosity. Recently, a very soft X-ray spectrum was observed in a rare and transient stellar-mass black hole. Here we report that the X-ray source P13 in the galaxy NGC 7793 is in a binary system with a period of about 64 days and exhibits all three canonical properties of ultraluminous sources. By modelling the strong optical and ultraviolet modulations arising from X-ray heating of the B9Ia donor star, we constrain the black hole mass to be less than 15 solar masses. Our results demonstrate that in P13, soft thermal emission and spectral curvature are indeed signatures of supercritical accretion. By analogy, ultraluminous X-ray sources with similar X-ray spectra and luminosities of up to a few times 10(40) ergs per second can be explained by supercritical accretion onto massive stellar-mass black holes. PMID:25297432

  13. A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source.

    PubMed

    Motch, C; Pakull, M W; Soria, R; Grisé, F; Pietrzyński, G

    2014-10-01

    Most ultraluminous X-ray sources have a typical set of properties not seen in Galactic stellar-mass black holes. They have luminosities of more than 3 × 10(39) ergs per second, unusually soft X-ray components (with a typical temperature of less than about 0.3 kiloelectronvolts) and a characteristic downturn in their spectra above about 5 kiloelectronvolts. Such puzzling properties have been interpreted either as evidence of intermediate-mass black holes or as emission from stellar-mass black holes accreting above their Eddington limit, analogous to some Galactic black holes at peak luminosity. Recently, a very soft X-ray spectrum was observed in a rare and transient stellar-mass black hole. Here we report that the X-ray source P13 in the galaxy NGC 7793 is in a binary system with a period of about 64 days and exhibits all three canonical properties of ultraluminous sources. By modelling the strong optical and ultraviolet modulations arising from X-ray heating of the B9Ia donor star, we constrain the black hole mass to be less than 15 solar masses. Our results demonstrate that in P13, soft thermal emission and spectral curvature are indeed signatures of supercritical accretion. By analogy, ultraluminous X-ray sources with similar X-ray spectra and luminosities of up to a few times 10(40) ergs per second can be explained by supercritical accretion onto massive stellar-mass black holes.

  14. Flat-Plate Solar-Collector Performance Evaluation with a Solar Simulator as a Basis for Collector Selection and Performance Prediction

    NASA Technical Reports Server (NTRS)

    Simon, F. F.

    1975-01-01

    The use of a solar simulator for performance determination permits collector testing under standard conditions of wind, ambient temperature, flow rate and sun. The performance results determined with the simulator have been found to be in good agreement with outdoor performance results. The measured thermal efficiency and evaluation of 23 collectors are reported which differ according to absorber material (copper, aluminum, steel), absorber coating (nonselective black paint, selective copper oxide, selective black nickel, selective black chrome), type of glazing material (glass, Tedlar, Lexan, antireflection glass), the use of honeycomb material and the use of vacuum to prevent thermal convection losses. The collectors were given performance rankings based on noon-hour solar conditions and all-day solar conditions. The determination with the simulator of an all-day collector performance was made possible by tests at different incident angles. The solar performance rankings were made based on whether the collector is to be used for pool heating, hot water, absorption air conditioning, heating, or for a solar Rankine machine.

  15. Solar neutrinos and the influences of opacity, thermal instability, additional neutrino sources, and a central black hole on solar models

    NASA Technical Reports Server (NTRS)

    Stothers, R. B.; Ezer, D.

    1972-01-01

    Significant quantities that affect the internal structure of the sun are examined for factors that reduce the temperature near the sun's center. The four factors discussed are: opacity, central black hole, thermal instability, and additional neutrino sources.

  16. Fountain pen nanochemistry: Atomic force control of chrome etching

    NASA Astrophysics Data System (ADS)

    Lewis, Aaron; Kheifetz, Yuri; Shambrodt, Efim; Radko, Anna; Khatchatryan, Edward; Sukenik, Chaim

    1999-10-01

    In this report we demonstrate a general method for affecting chemical reactions with a high degree of spatial control that has potentially wide applicability in science and technology. Our technique is based on complexing the delivery of liquid or gaseous materials through a cantilevered micropipette with an atomic force microscope that is totally integrated into a conventional optical microscope. Controlled etching of chrome is demonstrated without detectable effects on the underlying glass substrate. This simple combination allows for the nanometric spatial control of the whole world of chemical reactions in defined regions of surfaces. Applications of the technique in critical areas such as mask repair are likely.

  17. Polymeric Coatings Containing Antioxidants to Improve UV- and Heat Resistance of Chrome-Free Leather

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For automotive upholstery leather, UV and heat resistance are very important qualities, particularly for non-chrome-tanned (chrome-free) leather. One of our research endeavors has focused on an environmentally friendly finishing process that will improve the UV and heat resistance of automobile uph...

  18. Hysteresis and Stress Relaxation Studies for a Fibrous Collagen Material: Chrome-free Leather

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal hides are the most valuable coproduct of the meat industry, and most of those hides are converted into leather. Due to concerns over the use and disposal of chrome-tanned leather, the leather industry is now facing increasing scrutiny over its use of chrome as a tanning agent. The use of no...

  19. Treatments to enhance properties of chrome-free (wet white) leather

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of chrome-free or wet white leather, predominantly for upholstery leather, is fast approaching that which has been traditionally tanned with chrome. Recycling of auto parts, specifically the car seats, is driving the momentum towards this type of leather. Wet white leathers are sometime...

  20. FINAL REPORT FOR THE REDUCTION OF CHROME (VI) TO CHROME (III) IN THE SECONDARY WASTE STREAM OF THE EFFLUENT TREATMENT FACILITY

    SciTech Connect

    DUNCAN JB; GUTHRIE MD

    2008-08-29

    This report documents the laboratory results of RPP-PLAN-35958, Test Plan for the Effluent Treatment Facility to Reduce Chrome (VI) to Chrome (III) in the Secondary Waste Stream With the exception of the electrochemical corrosion scans, all work was carried out at the Center for Laboratory Science (CLS) located at the Columbia Basin College. This document summarizes the work carried out at CLS and includes the electrochemical scans and associated corrosion rates for 304 and 316L stainless steel.

  1. Evaluation of selective solar absorber surfaces. Semi-annual report, October 1, 1980-March 24, 1981

    SciTech Connect

    Osiecki, R.A.

    1981-04-01

    Testing of sample selective solar absorber coatings is reported. The first goal is to attempt to accelerate the optical property degradation of the coatings through exposure to a high humidity/high temperature environment. The second goal is the subsequent analysis of degraded and non-degraded coatings in an effort to determine the degradation mechanisms which operate on each coating. Surfaces tested included black chrome on aluminum, on copper, and on nickel plated copper, copper oxide/copper on mild steel, nickel-chromium oxide on nickel foil, chromate conversion coating, and a thickness sensitive silicone based paint. The optical properties of the samples in environmental exposure are tabulated. These properties include solar absorptance and near-normal emittance. (LEW)

  2. The effect of chrome adhesion layer on quartz resonator aging.

    SciTech Connect

    Wessendorf, Kurt O.; Ohlhausen, James Anthony

    2011-03-01

    This SAND report documents a late start LDRD designed to determine the possible aging effects of a quartz resonator gold adhesion layer. Sandia uses quartz resonators for applications. These applications require a very stable frequency source with excellent aging (low drift) characteristics. These parts are manufactured by one of our qualified vendors outside Sandia Laboratories, Statek Corp. Over the years we, Sandia and the vendor, have seen aging variations that have not been completely explained by the typical mechanisms known in the industry. One theory was that the resonator metallization may be contributing to the resonator aging. This LDRD would allow us to test and analyze a group of resonators with known differentiating metallization and via accelerated aging determine if a chrome adhesion layer used to accept the final gold plating may contribute to poor aging. We worked with our main vendor to design and manufacture a set of quartz resonators with a wide range of metallization thickness ratios between the chrome and gold that will allow us determine the cause of this aging and which plating thickness ratios provide the best aging performance while not degrading other key characteristics.

  3. Optoelectronic properties of Black-Silicon generated through inductively coupled plasma (ICP) processing for crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    Hirsch, Jens; Gaudig, Maria; Bernhard, Norbert; Lausch, Dominik

    2016-06-01

    The optoelectronic properties of maskless inductively coupled plasma (ICP) generated black silicon through SF6 and O2 are analyzed by using reflection measurements, scanning electron microscopy (SEM) and quasi steady state photoconductivity (QSSPC). The results are discussed and compared to capacitively coupled plasma (CCP) and industrial standard wet chemical textures. The ICP process forms parabolic like surface structures in a scale of 500 nm. This surface structure reduces the average hemispherical reflection between 300 and 1120 nm up to 8%. Additionally, the ICP texture shows a weak increase of the hemispherical reflection under tilted angles of incidence up to 60°. Furthermore, we report that the ICP process is independent of the crystal orientation and the surface roughness. This allows the texturing of monocrystalline, multicrystalline and kerf-less wafers using the same parameter set. The ICP generation of black silicon does not apply a self-bias on the silicon sample. Therefore, the silicon sample is exposed to a reduced ion bombardment, which reduces the plasma induced surface damage. This leads to an enhancement of the effective charge carrier lifetime up to 2.5 ms at 1015 cm-3 minority carrier density (MCD) after an atomic layer deposition (ALD) with Al2O3. Since excellent etch results were obtained already after 4 min process time, we conclude that the ICP generation of black silicon is a promising technique to substitute the industrial state of the art wet chemical textures in the solar cell mass production.

  4. Formation of artificial pores in nano-TiO2 photo-electrode films using acetylene-black for high-efficiency, dye-sensitized solar cells

    PubMed Central

    Cho, Tae-Yeon; Han, Chi-Whan; Jun, Yongseok; Yoon, Soon-Gil

    2013-01-01

    Acetylene-black paste without a light scattering layer was applied to meso-porous TiO2 photo-electrode films with a crystalline framework, a low residual carbon, and a tunable morphological pore size. The thermal-treated TiO2 photo-electrode films had an increased acetylene-black concentration with an increase in artificial pores and a decrease in residual carbon. The performance of dye-sensitized solar cells (DSSCs) was enhanced by the use of the TiO2 photo-anode pastes at various acetylene-black concentrations. The photo-conversion efficiency of the DSSCs using TiO2 photo-electrode films with 1.5 wt% acetylene-black was enhanced from 7.98 (no acetylene-black) to 9.75% without the integration of a light- scattering layer. PMID:23511122

  5. [A case of chrome asthma induced by exposure to the stone cutter dust].

    PubMed

    Onizuka, Reiko; Tanabe, Kimiko; Nakayama, Yoshihisa; Fukuchi, Tetsuroh; Nakata, Kazunori; Hiki, Toshinobu

    2006-12-01

    The case of a forty-six year old, male patient with asthma caused by exposure to dust containing chrome is presented. When the patient was nineteen years old, he started working as a stonemason in a factory. He cut and ground stone with a stone-cutter to make statues and tombstones. Three years after staring to work, contact dermatitis was observed on his arms and hands. Within six years of work, he suffered from chronic coughing. After eight years, he experienced bronchial asthma attacks with wheezing and dyspnea. He had been exposed to dust for eight years before developing asthma. The symptoms increased gradually. He fell into severe asthma attacks causing unconsciousness and dyspnea. Several common therapies were not effective. The characteristics of his clinical course and occupational history suggested that the asthma must be caused by exposure to dust containing metal generated in the factory. Skin Patch Tests (SPT) were performed for cobalt, copper, iron, chrome, tin, and manganese salt. The result of the SPT indicated a strong positive result for potassium dichromate and positive for chromium sulfate, but did not show any indications in the control or for other metallic salt. Fluorescent X-ray analysis detected that chrome was present in the powder dust under the stone-cutter machine. However, the fluorescent X-ray analysis did not detect chrome in the stone materials. It was suggested that chrome must be contained in the metal dust generated from the steel cutter used to cut off and grind the stone. The metal component in the used cutter edge and the unused cutter edge were analyzed with electro-probe microanalyzer (EPMA). The result revealed that chrome was contained in the used, dull cutter edge and not in the new sharp cutter edge. Thus, the patient had been exposed to the dust containing chrome generated from part of the stainless steel of cutter. He had sensitized to chrome and this had caused the occupational chrome-asthma.

  6. Hexavalent Chrome Free Coatings for Electronics Applications: Joint Test Report

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt

    2012-01-01

    Regardless of the corrosivity of the environment, all metals require periodic maintenance activity to guard against the insidious effects of corrosion and thus ensure that alloys meet or exceed design or performance life. The standard practice for protecting metallic substrates is the application of a coating system. Applied coating systems work via a variety of methods (barrier, galvanic, and/or inhibitor) and adhere to the substrate through a combination of chemical and physical bonds. For years hexavalent chromium has been a widely used element within applied coating systems because of its self healing and corrosion resistant properties. Occupational Safety and Health Administration (OSHA) studies have concluded that hexavalent chromium (hex chrome) is carcinogenic and poses significant risk to human health. On May 5, 2011 amendments to the Defense Federal Acquisition Regulation Supplement (DFARS) were issued in the Federal Register. Subpart 223.73 prohibits contracts from requiring hexavalent chromium in deliverables unless certain exceptions apply. These exceptions include authorization from a general or flag officer and members of the Senior Executive Service from a Program Executive Office, and unmodified legacy systems. Otherwise, Subpart 252.223-7008 provides the contract clause prohibiting contractors from using or delivering hexavalent chromium in a concentration greater than 0.1 percent by weight for all new contracts and to be included down to subcontractors for supplies, maintenance and repair services, and construction materials. National Aeronautics and Space Administration (NASA), Department of Defense (DoD), and industry stakeholders continue to search for alternatives to hex chrome in coatings applications that meet their performance requirements in corrosion protection, cost, operability, and health and safety, while typically specifying that performance must be equal to or greater than existing systems.

  7. GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence

    NASA Astrophysics Data System (ADS)

    Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Bejger, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fong, H.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gehrels, N.; Gemme, G.; Geng, P.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hamilton, H.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jian, L.; Jiménez-Forteza, F.; Johnson, W. W.; Johnson-McDaniel, N. K.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chi-Woong; Kim, Chunglee; Kim, J.; Kim, K.; Kim, N.; Kim, W.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Lewis, J. B.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Nedkova, K.; Nelemans, G.; Nelson, T. J. N.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Setyawati, Y.; Shaddock, D. A.; Shaffer, T.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stevenson, S. P.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tomlinson, C.; Tonelli, M.; Tornasi, Z.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; Boyle, M.; Hemberger, D.; Kidder, L. E.; Lovelace, G.; Ossokine, S.; Scheel, M.; Szilagyi, B.; Teukolsky, S.; LIGO Scientific Collaboration; Virgo Collaboration

    2016-06-01

    We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5 σ . The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3. 4-0.9+0.7×10-22 . The inferred source-frame initial black hole masses are 14.2-3.7+8.3 M⊙ and 7. 5-2.3+2.3 M⊙, and the final black hole mass is 20.8-1.7+6.1 M⊙. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 44 0-190+180 Mpc corresponding to a redshift of 0.0 9-0.04+0.03. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

  8. [Experiment results of conduction, spectral induced polarization and dielectric characteristics for chrome-contaminated soil].

    PubMed

    Nai, Chang-Xin; Liu, Yu-Qiang; Liu, Hao-Rui; Dong, Lu

    2011-03-01

    The resistivity, complex resistivity and complex permittivity of the chrome-contaminated soil were studied. Under the different pollution concentration and water content in the soil samples conditions, the relations between the resistivity, complex resistivity and complex permittivity of the chrome-contaminated soil and water content and the concentration of pollution were analyzed. When adding chrome pollution with different concentrations and water content, the experimental results show that the resistivity and complex resistivity of all the soil samples decreased with the pollution concentration and water content increased; but the phase of complex resistivity, which reflects the soil's capacitance, decreased below the 20 kHz and increase above the 20 kHz frequency. The real part and imaginary part of complex resostivity increased with the increase of pollution concentration and water content. The concentration of chrome pollutions and water content were the two main factor to determine the soil electrical characteristics.

  9. Magnetic microphases in chrome-spinels from alpine-type ultramafic rocks, Central Urals

    NASA Astrophysics Data System (ADS)

    Sherendo, T. A.; Mitrofanov, V. Ya.; Martyshko, P. S.; Vazhenin, V. A.; Pamyatnykh, L. A.; Alekseev, A. V.

    2014-05-01

    The ore and accessory chrome-spinels from metamorphosed dunites of the Cr-bearing Klyuchevskoi alpine-type ultramafic massif are studied. As a result of use of thermomagnetic analysis in the range of 4-900 K, magnetic resonance spectroscopy, and magnetic-force microscopy, secondary magnetic Fe3+-enriched microphases chaotically distributed in the primary nonmagnetic mineral were revealed for the first time in accessory chrome-spinels. It was established that the metamorphosed accessory chrome-spinels produce the magnetic properties of the host rocks and the primary nonmagnetic chrome-spinels forming ore bodies remains almost unaltered. This originates the contrast of magnetic properties between the ore body and host rocks and provides the geomagnetic anomaly in the ore-hosting zone.

  10. Investigation of Ceramic, Graphite, and Chrome-plated Graphite Nozzles on Rocket Engine

    NASA Technical Reports Server (NTRS)

    Kinney, George R; Lidman, William G

    1949-01-01

    The use of ceramic material for rocket nozzles and the effectiveness of preventing oxidation and erosion of graphite nozzles by chrome-plating the internal surface were investigated. A supported ceramic nozzle, cracked by initial operation, was operated a second time without further cracking or damage. Chrome-plating the internal surface of graphite nozzles effectively prevented oxidation and erosion that occurred during operation with unprotected graphite.

  11. Nondestructive detection of lead chrome green in tea by Raman spectroscopy

    PubMed Central

    Li, Xiao-Li; Sun, Chan-Jun; Luo, Liu-Bin; He, Yong

    2015-01-01

    Raman spectroscopy was first adopted for rapid detecting a hazardous substance of lead chrome green in tea, which was illegally added to tea to disguise as high-quality. 160 samples of tea infusion with different concentrations of lead chrome green were prepared for Raman spectra acquirement in the range of 2804 cm−1–230 cm−1 and the spectral intensities were calibrated with relative intensity standards. Then wavelet transformation (WT) was adopted to extract information in different time and frequency domains from Raman spectra, and the low-frequency approximation signal (ca4) was proved as the most important information for establishment of lead chrome green measurement model, and the corresponding partial least squares (PLS) regression model obtained good performance in prediction with Rp and RMSEP of 0.936 and 0.803, respectively. To further explore the important wavenumbers closely related to lead chrome green, successive projections algorithm (SPA) was proposed. Finally, 8 characteristic wavenumbers closely related to lead chrome green were obtained and a more convenient and fast model was also developed. These results proved the feasibility of Raman spectroscopy for nondestructive detection of lead chrome green in tea quality control. PMID:26508516

  12. Nondestructive detection of lead chrome green in tea by Raman spectroscopy.

    PubMed

    Li, Xiao-Li; Sun, Chan-Jun; Luo, Liu-Bin; He, Yong

    2015-01-01

    Raman spectroscopy was first adopted for rapid detecting a hazardous substance of lead chrome green in tea, which was illegally added to tea to disguise as high-quality. 160 samples of tea infusion with different concentrations of lead chrome green were prepared for Raman spectra acquirement in the range of 2804 cm(-1)-230 cm(-1) and the spectral intensities were calibrated with relative intensity standards. Then wavelet transformation (WT) was adopted to extract information in different time and frequency domains from Raman spectra, and the low-frequency approximation signal (ca4) was proved as the most important information for establishment of lead chrome green measurement model, and the corresponding partial least squares (PLS) regression model obtained good performance in prediction with Rp and RMSEP of 0.936 and 0.803, respectively. To further explore the important wavenumbers closely related to lead chrome green, successive projections algorithm (SPA) was proposed. Finally, 8 characteristic wavenumbers closely related to lead chrome green were obtained and a more convenient and fast model was also developed. These results proved the feasibility of Raman spectroscopy for nondestructive detection of lead chrome green in tea quality control. PMID:26508516

  13. A comparison of black, blue, and white backgrounds for high density solar modules

    NASA Astrophysics Data System (ADS)

    Hoelscher, J. F.; Artigliere, F.; Preis, S.; Stepanian, G.

    The electrical output of a photovoltaic module is affected through two different mechanisms when the color of the back is varied: The light trapping effect and, indirectly, through the difference in cell temperature. To determine the magnitude of each of these effects, experiments were performed on modules with three different backs, (1) black (on both sides), (2) white (on both sides), and (3) blue (on the sun side) and white (on the back side). It was determined that the module with the white back was most efficient. The blue-backed module produced 1.6 percent less power and the black-backed module produced 3.6 percent less power (than the white) at 100 mw/sq cm illumination.

  14. GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence.

    PubMed

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    2016-06-17

    We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4_{-0.9}^{+0.7}×10^{-22}. The inferred source-frame initial black hole masses are 14.2_{-3.7}^{+8.3}M_{⊙} and 7.5_{-2.3}^{+2.3}M_{⊙}, and the final black hole mass is 20.8_{-1.7}^{+6.1}M_{⊙}. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440_{-190}^{+180}  Mpc corresponding to a redshift of 0.09_{-0.04}^{+0.03}. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

  15. GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence.

    PubMed

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Mezzani, F; Miao, H; Michel, C; Middleton, H; Mikhailov, E E; Milano, L; Miller, A L; Miller, A; Miller, B B; Miller, J; Millhouse, M; Minenkov, Y; Ming, J; Mirshekari, S; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moggi, A; Mohan, M; Mohapatra, S R P; Montani, M; Moore, B C; Moore, C J; Moraru, D; Moreno, G; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, G; Muir, A W; Mukherjee, Arunava; Mukherjee, D; Mukherjee, S; Mukund, N; Mullavey, A; Munch, J; Murphy, D J; Murray, P G; Mytidis, A; Nardecchia, I; Naticchioni, L; Nayak, R K; Nedkova, K; Nelemans, G; Nelson, T J N; Neri, M; Neunzert, A; Newton, G; Nguyen, T T; Nielsen, A B; Nissanke, S; Nitz, A; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Oberling, J; Ochsner, E; O'Dell, J; Oelker, E; Ogin, G H; Oh, J J; Oh, S H; Ohme, F; Oliver, M; Oppermann, P; Oram, Richard J; O'Reilly, B; O'Shaughnessy, R; Ottaway, D J; Overmier, H; Owen, B J; Pai, A; Pai, S A; Palamos, J R; Palashov, O; Palomba, C; 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Rolland, L; Rollins, J G; Roma, V J; Romano, J D; Romano, R; Romanov, G; Romie, J H; Rosińska, D; Rowan, S; Rüdiger, A; Ruggi, P; Ryan, K; Sachdev, S; Sadecki, T; Sadeghian, L; Sakellariadou, M; Salconi, L; Saleem, M; Salemi, F; Samajdar, A; Sammut, L; Sanchez, E J; Sandberg, V; Sandeen, B; Sanders, J R; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Sauter, O E S; Savage, R L; Sawadsky, A; Schale, P; Schilling, R; Schmidt, J; Schmidt, P; Schnabel, R; Schofield, R M S; Schönbeck, A; Schreiber, E; Schuette, D; Schutz, B F; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Setyawati, Y; Shaddock, D A; Shaffer, T; Shahriar, M S; Shaltev, M; Shapiro, B; Shawhan, P; Sheperd, A; Shoemaker, D H; Shoemaker, D M; Siellez, K; Siemens, X; Sieniawska, M; Sigg, D; Silva, A D; Singer, A; Singer, L P; Singh, A; Singh, R; Singhal, A; Sintes, A M; Slagmolen, B J J; Smith, J R; Smith, N D; Smith, R J E; Son, E J; Sorazu, B; Sorrentino, F; Souradeep, T; Srivastava, A K; Staley, A; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stephens, B C; Stevenson, S P; Stone, R; Strain, K A; Straniero, N; Stratta, G; Strauss, N A; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Sun, L; Sunil, S; Sutton, P J; Swinkels, B L; Szczepańczyk, M J; Tacca, M; Talukder, D; Tanner, D B; Tápai, M; Tarabrin, S P; Taracchini, A; Taylor, R; Theeg, T; Thirugnanasambandam, M P; Thomas, E G; Thomas, M; Thomas, P; Thorne, K A; Thrane, E; Tiwari, S; Tiwari, V; Tokmakov, K V; Toland, K; Tomlinson, C; Tonelli, M; Tornasi, Z; Torres, C V; Torrie, C I; Töyrä, D; Travasso, F; Traylor, G; Trifirò, D; Tringali, M C; Trozzo, L; Tse, M; Turconi, M; Tuyenbayev, D; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; Vallisneri, M; van Bakel, N; van Beuzekom, M; van den Brand, J F J; Van Den Broeck, C; Vander-Hyde, D C; van der Schaaf, L; van Heijningen, J V; van Veggel, A A; Vardaro, M; Vass, S; Vasúth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Vetrano, F; Viceré, A; Vinciguerra, S; Vine, D J; Vinet, J-Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Voss, D V; Vousden, W D; Vyatchanin, S P; Wade, A R; Wade, L E; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, M; Wang, X; Wang, Y; Ward, R L; Warner, J; Was, M; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Wen, L; Weßels, P; Westphal, T; Wette, K; Whelan, J T; Whiting, B F; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Woehler, J; Worden, J; Wright, J L; Wu, D S; Wu, G; Yablon, J; Yam, W; Yamamoto, H; Yancey, C C; Yu, H; Yvert, M; Zadrożny, A; Zangrando, L; Zanolin, M; Zendri, J-P; Zevin, M; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhou, Z; Zhu, X J; Zucker, M E; Zuraw, S E; Zweizig, J; Boyle, M; Hemberger, D; Kidder, L E; Lovelace, G; Ossokine, S; Scheel, M; Szilagyi, B; Teukolsky, S

    2016-06-17

    We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4_{-0.9}^{+0.7}×10^{-22}. The inferred source-frame initial black hole masses are 14.2_{-3.7}^{+8.3}M_{⊙} and 7.5_{-2.3}^{+2.3}M_{⊙}, and the final black hole mass is 20.8_{-1.7}^{+6.1}M_{⊙}. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440_{-190}^{+180}  Mpc corresponding to a redshift of 0.09_{-0.04}^{+0.03}. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity. PMID:27367379

  16. Calculations of Solar Shortwave Heating Rates due to Black Carbon and Ozone Absorption Using in Situ Measurements

    NASA Technical Reports Server (NTRS)

    Gao, R. S.; Hall, S. R.; Swartz, W. H.; Spackman, J. R.; Watts, L. A.; Fahey, D. W.; Aikin, K. C.; Shetter, R. E.; Bui, T. P.

    2008-01-01

    Results for the solar heating rates in ambient air due to absorption by black-carbon (BC) containing particles and ozone are presented as calculated from airborne observations made in the tropical tropopause layer (TTL) in January-February 2006. The method uses airborne in situ observations of BC particles, ozone and actinic flux. Total BC mass is obtained along the flight track by summing the masses of individually detected BC particles in the range 90 to 600-nm volume-equivalent diameter, which includes most of the BC mass. Ozone mixing ratios and upwelling and partial downwelling solar actinic fluxes were measured concurrently with BC mass. Two estimates used for the BC wavelength-dependent absorption cross section yielded similar heating rates. For mean altitudes of 16.5, 17.5, and 18.5 km (0.5 km) in the tropics, average BC heating rates were near 0.0002 K/d. Observed BC coatings on individual particles approximately double derived BC heating rates. Ozone heating rates exceeded BC heating rates by approximately a factor of 100 on average and at least a factor of 4, suggesting that BC heating rates in this region are negligible in comparison.

  17. Experimental investigation of a nanofluid absorber employed in a low-profile, concentrated solar thermal collector

    NASA Astrophysics Data System (ADS)

    Li, Qiyuan; Zheng, Cheng; Mesgari, Sara; Hewakuruppu, Yasitha L.; Hjerrild, Natasha; Crisostomo, Felipe; Morrison, Karl; Woffenden, Albert; Rosengarten, Gary; Scott, Jason A.; Taylor, Robert A.

    2015-12-01

    Recent studies [1-3] have demonstrated that nanotechnology, in the form of nanoparticles suspended in water and organic liquids, can be employed to enhance solar collection via direct volumetric absorbers. However, current nanofluid solar collector experimental studies are either relevant to low-temperature flat plate solar collectors (<100 °C) [4] or higher temperature (>100 °C) indoor laboratory-scale concentrating solar collectors [1, 5]. Moreover, many of these studies involve in thermal properties of nanofluid (such as thermal conductivity) enhancement in solar collectors by using conventional selective coated steel/copper tube receivers [6], and no full-scale concentrating collector has been tested at outdoor condition by employing nanofluid absorber [2, 6]. Thus, there is a need of experimental researches to evaluate the exact performance of full-scale concentrating solar collector by employing nanofluids absorber at outdoor condition. As reported previously [7-9], a low profile (<10 cm height) solar thermal concentrating collector was designed and analysed which can potentially supply thermal energy in the 100-250 °C range (an application currently met by gas and electricity). The present study focuses on the design and experimental investigation of a nanofluid absorber employed in this newly designed collector. The nanofluid absorber consists of glass tubes used to contain chemically functionalized multi-walled carbon nanotubes (MWCNTs) dispersed in DI water. MWCNTs (average diameter of 6-13 nm and average length of 2.5-20 μm) were functionalized by potassium persulfate as an oxidant. The nanofluids were prepared with a MCWNT concentration of 50 +/- 0.1 mg/L to form a balance between solar absorption depth and viscosity (e.g. pumping power). Moreover, experimentally comparison of the thermal efficiency between two receivers (a black chrome-coated copper tube versus a MWCNT nanofluid contained within a glass tubetube) is investigated. Thermal

  18. Floatable, Self-Cleaning, and Carbon-Black-Based Superhydrophobic Gauze for the Solar Evaporation Enhancement at the Air-Water Interface.

    PubMed

    Liu, Yiming; Chen, Jingwei; Guo, Dawei; Cao, Moyuan; Jiang, Lei

    2015-06-24

    Efficient solar evaporation plays an indispensable role in nature as well as the industry process. However, the traditional evaporation process depends on the total temperature increase of bulk water. Recently, localized heating at the air-water interface has been demonstrated as a potential strategy for the improvement of solar evaporation. Here, we show that the carbon-black-based superhydrophobic gauze was able to float on the surface of water and selectively heat the surface water under irradiation, resulting in an enhanced evaporation rate. The fabrication process of the superhydrophobic black gauze was low-cost, scalable, and easy-to-prepare. Control experiments were conducted under different light intensities, and the results proved that the floating black gauze achieved an evaporation rate 2-3 times higher than that of the traditional process. A higher temperature of the surface water was observed in the floating gauze group, revealing a main reason for the evaporation enhancement. Furthermore, the self-cleaning ability of the superhydrophobic black gauze enabled a convenient recycling and reusing process toward practical application. The present material may open a new avenue for application of the superhydrophobic substrate and meet extensive requirements in the fields related to solar evaporation. PMID:26027770

  19. Floatable, Self-Cleaning, and Carbon-Black-Based Superhydrophobic Gauze for the Solar Evaporation Enhancement at the Air-Water Interface.

    PubMed

    Liu, Yiming; Chen, Jingwei; Guo, Dawei; Cao, Moyuan; Jiang, Lei

    2015-06-24

    Efficient solar evaporation plays an indispensable role in nature as well as the industry process. However, the traditional evaporation process depends on the total temperature increase of bulk water. Recently, localized heating at the air-water interface has been demonstrated as a potential strategy for the improvement of solar evaporation. Here, we show that the carbon-black-based superhydrophobic gauze was able to float on the surface of water and selectively heat the surface water under irradiation, resulting in an enhanced evaporation rate. The fabrication process of the superhydrophobic black gauze was low-cost, scalable, and easy-to-prepare. Control experiments were conducted under different light intensities, and the results proved that the floating black gauze achieved an evaporation rate 2-3 times higher than that of the traditional process. A higher temperature of the surface water was observed in the floating gauze group, revealing a main reason for the evaporation enhancement. Furthermore, the self-cleaning ability of the superhydrophobic black gauze enabled a convenient recycling and reusing process toward practical application. The present material may open a new avenue for application of the superhydrophobic substrate and meet extensive requirements in the fields related to solar evaporation.

  20. Flight solar calibrations using the Mirror Attenuator Mosaic (MAM): Low scattering mirror

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III

    1992-01-01

    Measurements of solar radiances reflected from the mirror attenuator mosaic (MAM) were used to calibrate the shortwave portions of the Earth Radiation Budget Experiment (ERBE) thermistor bolometer scanning radiometers. The MAM is basically a low scattering mirror which has been used to attenuate and reflect solar radiation into the fields of view for the broadband shortwave (0.2 to 5 micrometers) and total (0.2 to 50.0+ micrometers) ERBE scanning radiometers. The MAM assembly consists of a tightly packed array of aluminum, 0.3175-cm diameter concave spherical mirrors and field of view limiting baffles. The spherical mirrors are masked by a copper plate, electro-plated with black chrome. Perforations (0.14 centimeter in diameter) in the copper plate serve as apertures for the mirrors. Black anodized aluminum baffles limit the MAM clear field of view to 7.1 degrees. The MAM assemblies are located on the Earth Radiation Budget Satellite (ERBS) and on the National Oceanic and Atmospheric Administration NOAA-9 and NOAA-10 spacecraft. The 1984-1985 ERBS and 1985-1986 NOAA-9 solar calibration datasets are presented. Analyses of the calibrations indicate that the MAM exhibited no detectable degradation in its reflectance properties and that the gains of the shortwave scanners did not change. The stability of the shortwave radiometers indicates that the transmission of the Suprasil W1 filters did not degrade detectably when exposed to Earth/atmosphere-reflected solar radiation.

  1. Comparison of selective transmitters for solar thermal applications.

    PubMed

    Taylor, Robert A; Hewakuruppu, Yasitha; DeJarnette, Drew; Otanicar, Todd P

    2016-05-10

    Solar thermal collectors are radiative heat exchangers. Their efficacy is dictated predominantly by their absorption of short wavelength solar radiation and, importantly, by their emission of long wavelength thermal radiation. In conventional collector designs, the receiver is coated with a selectively absorbing surface (Black Chrome, TiNOx, etc.), which serves both of these aims. As the leading commercial absorber, TiNOx consists of several thin, vapor deposited layers (of metals and ceramics) on a metal substrate. In this technology, the solar absorption to thermal emission ratio can exceed 20. If a solar system requires an analogous transparent component-one which transmits the full AM1.5 solar spectrum, but reflects long wavelength thermal emission-the technology is much less developed. Bespoke "heat mirrors" are available from optics suppliers at high cost, but the closest mass-produced commercial technology is low-e glass. Low-e glasses are designed for visible light transmission and, as such, they reflect up to 50% of available solar energy. To address this technical gap, this study investigated selected combinations of thin films that could be deposited to serve as transparent, selective solar covers. A comparative numerical analysis of feasible materials and configurations was investigated using a nondimensional metric termed the efficiency factor for selectivity (EFS). This metric is dependent on the operation temperature and solar concentration ratio of the system, so our analysis covered the practical range for these parameters. It was found that thin films of indium tin oxide (ITO) and ZnS-Ag-ZnS provided the highest EFS. Of these, ITO represents the more commercially viable solution for large-scale development. Based on these optimized designs, proof-of-concept ITO depositions were fabricated and compared to commercial depositions. Overall, this study presents a systematic guide for creating a new class of selective, transparent

  2. Comparison of selective transmitters for solar thermal applications.

    PubMed

    Taylor, Robert A; Hewakuruppu, Yasitha; DeJarnette, Drew; Otanicar, Todd P

    2016-05-10

    Solar thermal collectors are radiative heat exchangers. Their efficacy is dictated predominantly by their absorption of short wavelength solar radiation and, importantly, by their emission of long wavelength thermal radiation. In conventional collector designs, the receiver is coated with a selectively absorbing surface (Black Chrome, TiNOx, etc.), which serves both of these aims. As the leading commercial absorber, TiNOx consists of several thin, vapor deposited layers (of metals and ceramics) on a metal substrate. In this technology, the solar absorption to thermal emission ratio can exceed 20. If a solar system requires an analogous transparent component-one which transmits the full AM1.5 solar spectrum, but reflects long wavelength thermal emission-the technology is much less developed. Bespoke "heat mirrors" are available from optics suppliers at high cost, but the closest mass-produced commercial technology is low-e glass. Low-e glasses are designed for visible light transmission and, as such, they reflect up to 50% of available solar energy. To address this technical gap, this study investigated selected combinations of thin films that could be deposited to serve as transparent, selective solar covers. A comparative numerical analysis of feasible materials and configurations was investigated using a nondimensional metric termed the efficiency factor for selectivity (EFS). This metric is dependent on the operation temperature and solar concentration ratio of the system, so our analysis covered the practical range for these parameters. It was found that thin films of indium tin oxide (ITO) and ZnS-Ag-ZnS provided the highest EFS. Of these, ITO represents the more commercially viable solution for large-scale development. Based on these optimized designs, proof-of-concept ITO depositions were fabricated and compared to commercial depositions. Overall, this study presents a systematic guide for creating a new class of selective, transparent

  3. Recycling of Chrome Tanned Leather Dust in Acrylonitrile Butadiene Rubber

    NASA Astrophysics Data System (ADS)

    El-Sabbagh, Salwa H.; Mohamed, Ola A.

    2010-06-01

    Concerns on environmental waste problem caused by chrome tanned leather wastes in huge amount have caused an increasing interest in developing this wastes in many composite formation. This leather dust was used as filler in acrylonitrile butadiene rubber (NBR) before treatment and after treatment with ammonia solution and sod. formate. Different formulations of NBR/ leather dust (untreated-treated with ammonia solution—treated with sod. formate) composites are prepared. The formed composite exhibit a considerable improvement in some of their properties such as rheometric characteristics especially with composites loaded with treated leather dust. Tensile strength, modulus at 100% elongation, hardness and youngs modulus were improved then by further loading start to be steady or decrease. Cross linking density in toluene were increased by incorporation of leather dust treated or untreated resulting in decreases in equilibrium swelling. Distinct increase in the ageing coefficient of both treated and untreated leather with drop in NBR vulcanizates without leather dust. Addition of leather dust treated or untreated exhibit better thermal stability.

  4. Nitrogen and boron ion implantation into electrodeposited hard chrome

    SciTech Connect

    Walter, K.C.; Tesmer, J.R.; Scarborough, W.K.; Woodring, J.S.; Nastasi, M.; Kern, K.T.

    1996-10-01

    Electrodeposited hard chrome was ion implanted with N alone, B alone, and a combination. Separate N and B implantation was done at 75 keV and incident doses of 2, 4, and 8x10{sup 17} at/cm{sup 2}. Samples with both N/B implants used 75 keV and incident dose levels of 4x10{sup 17} N- and B-at/cm{sup 2}. Beam-line system was used. Retained dose was measured using ion beam analysis, which indicated most of the incident dose was retained. Surface hardness, wear coefficient, and friction coefficient were determined by nanohardness indentation and pin-on-disk wear. At a depth of 50 nm, surface hardness increased from 18{+-}1 GPa (unimplanted) to a max of 23{+-}4 GPa for B implant and 26{+-}1 GPa for N implant. the wear coefficient was reduced by 1.3x to 7.4x, depending on implantation. N implant results in lower wear coefficients than B implant.

  5. 40 CFR 425.10 - Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS LEATHER TANNING AND FINISHING... finished leather by chemically dissolving the hide hair, chrome tanning, and retan-wet finishing....

  6. Solar-collector-materials exposure to the IPH site environment. Volume 1. Final report

    SciTech Connect

    Morris, V.L.

    1982-01-01

    In-situ environmental exposure tests were conducted at nine proposed intermediate-temperature Industrial Process Heat (IPH) sites. Three types of reflector materials were evaluated for survivability at the nine sites: second-surface silvered glass, aluminized acrylic FEK-244 film on aluminumsubstrate and Alzak (electropolished aluminum) on aluminium substrate. Black chrome absorber material and low-iron float glass were evaluated for thermal, photochemical, and environmental degradation. The reflector specimens were monitored for decreases in specular and hemispherical reflectance due to soil buildup. The absorber material was evaluated for changes in solar absorptivity and emissivity, and the float glass was monitored for changes in transmissivity. Surface and subsurface defects on all materials were examined microscopically and, where deemed of note, were documented photographically.

  7. Solar-collector materials exposure to the IPH site environment. Final report

    SciTech Connect

    Morris, V.L.

    1982-01-01

    In-situ environmental exposure tests were conducted at nine proposed intermediate-temperature Industrial Process Heat (IPH) sites. Three types of reflector materials were evaluated for survivability at the nine sites: second-surface silvered glass, aluminized acrylic FEK-244 film on aluminum substrate, and Alzak (electropolished aluminum) on aluminum substrate. Black chrome absorber material and low-iron float glass were evaluated for thermal, photochemical, and environmental degradation. The reflector specimens were monitored for decreases in specular and hemispherical reflectance due to soil buildup. The absorber material was evaluated for changes in solar absorptivity and emissivity, and the float glass was monitored for changes in transmissivity. Surface and subsurface defects on all materials were examined microscopically and, where deemed of note, were documented photographically.

  8. Toward a planar black silicon technology for 50 μm-thin crystalline silicon solar cells.

    PubMed

    Song, Jae-Won; Nam, Yoon-Ho; Park, Min-Joon; Yoo, Bongyoung; Cho, Jun-Sik; Wehrspohn, Ralf B; Lee, Jung-Ho

    2016-09-01

    Auger and surface recombinations are major drawbacks that deteriorate a photon-to-electron conversion efficiencies in nanostructured (NS) Si solar cells. As an alternative to conventional frontside nanostructuring, we report how backside nanostructuring is beneficial for carrier collection during photovoltaic operation that utilizes a 50-μm-thin wafer. Ultrathin (4.3-nm-thin) zinc oxide was also effective for providing passivated tunneling contacts at the nanostructured backsides, which led to the enhancement of 24% in power conversion efficiency.

  9. The X-Ray Properties of Million Solar Mass Black Holes

    NASA Astrophysics Data System (ADS)

    Plotkin, Richard. M.; Gallo, Elena; Haardt, Francesco; Miller, Brendan P.; Wood, Callum J. L.; Reines, Amy E.; Wu, Jianfeng; Greene, Jenny E.

    2016-07-01

    We present new Chandra X-ray observations of seven low-mass black holes ({M}{{BH}}≈ {10}6 {M}⊙ ) accreting at low-bolometric Eddington ratios between -2.0≲ {log}{L}{{bol}}/{L}{{Edd}}≲ -1.5. We compare the X-ray properties of these seven low-mass active galactic nuclei (AGNs) to a total of 73 other low-mass AGNs in the literature with published Chandra observations (with Eddington ratios extending from -2.0≲ {log}{L}{{bol}}/{L}{{Edd}}≲ -0.1). We do not find any statistical differences between the low and high Eddington ratio low-mass AGNs in the distributions of their X-ray to ultraviolet luminosity ratios ({α }{{ox}}), or in their X-ray spectral shapes. Furthermore, the {α }{{ox}} distribution of low-{L}{{bol}}/{L}{{Edd}} AGNs displays an X-ray weak tail that is also observed within high-{L}{{bol}}/{L}{{Edd}} objects. Our results indicate that between -2≲ {log}{L}{{bol}}/{L}{{Edd}}≲ -0.1, there is no systematic change in the structure of the accretion flow for active galaxies hosting {10}6 {M}⊙ black holes. We examine the accuracy of current bolometric luminosity estimates for our low-{L}{{bol}}/{L}{{Edd}} objects with new Chandra observations, and it is plausible that their Eddington ratios could be underestimated by up to an order of magnitude. If so, then in analogy with weak emission line quasars, we suggest that accretion from a geometrically thick, radiatively inefficient “slim disk” could explain their diverse properties in {α }{{ox}}. Alternatively, if current Eddington ratios are correct (or overestimated), then the X-ray weak tail would imply that there is diversity in disk/corona couplings among individual low-mass objects. Finally, we conclude by noting that the {α }{{ox}} distribution for low-mass black holes may have favorable consequences for the epoch of cosmic reionization being driven by AGN.

  10. Toward a planar black silicon technology for 50 μm-thin crystalline silicon solar cells.

    PubMed

    Song, Jae-Won; Nam, Yoon-Ho; Park, Min-Joon; Yoo, Bongyoung; Cho, Jun-Sik; Wehrspohn, Ralf B; Lee, Jung-Ho

    2016-09-01

    Auger and surface recombinations are major drawbacks that deteriorate a photon-to-electron conversion efficiencies in nanostructured (NS) Si solar cells. As an alternative to conventional frontside nanostructuring, we report how backside nanostructuring is beneficial for carrier collection during photovoltaic operation that utilizes a 50-μm-thin wafer. Ultrathin (4.3-nm-thin) zinc oxide was also effective for providing passivated tunneling contacts at the nanostructured backsides, which led to the enhancement of 24% in power conversion efficiency. PMID:27607725

  11. Solar Success Story at Moanalua Terrace

    SciTech Connect

    Not Available

    1999-03-01

    Solar systems prove to be the environmentally and economically sound choice for heating water in U.S. Navy housing at Moanalua Terrace in Pearl Harbor, Hawaii. Hawaii is a perfect environment for solar water heating,'' according to Alan Ikeda, a Housing Management Specialist with the Pacific Naval Facility Engineering Command Housing Department in Pearl Harbor, Hawaii. ''The sun shines most of the time, we don't have to worry about freezing, the state offers a 35% solar tax credit, and our local utility supports the purchase and installation of solar systems with generous rebates.'' The Hawaiian Electric Company's (HECO's) $1,500 per unit rebate for solar water heaters installed on new construction helped persuade the Navy to take advantage of Hawaii's solar resource and install solar water heaters on family housing units. At Moanalua Terrace, the Navy had demolished 752 units of family housing, which they are rebuilding in four phases. Designers decided to use the opportunity to give the solar systems a try. When the 100 homes in Phase I were built, money was not available for solar water heaters. However, Ikeda subsequently secured a $130,000 grant from the U.S. Department of Energy's (DOE's) Federal Energy Management Program (FEMP) to retrofit the Phase I homes with solar systems. In retrofit applications, HECO rebates $800 per unit ($80,000 total) on approved equipment, and Pearl Harbor Family Housing will pay the difference of the estimated $340,000 total cost, or about $130,000. The 136 units built during Phase II of the Moanalua Terrace project included solar systems in their specifications, so the Navy was able to take advantage of the $1,500 per system HECO rebate for approved solar water heaters in new construction. The Navy chose direct (open-loop) active systems that circulate potable water through flat-plate collectors coated with a black chrome selective surface. Each system consists of a 4-foot by 8-foot (1.2-m by 2.4-m) collector made by American

  12. Hexavalent Chrome Free Coatings for Electronics: Electromagnetic Interference (EMI) Shielding Effectiveness (SE)

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2016-01-01

    Determine the suitability of trivalent chromium conversion coatings that meet the requirements of MIL-DTL-5541, Type II, for use in applications where high-frequency electrical performance is important. Evaluate the ability of hexavalent chrome free pretreated aluminum to form adequate EMI seals, and maintain that seal while being subjected to harsh environmental conditions. Assess the performance of trivalent chromium pretreatments against a known control hexavalent chrome pretreatment before and after they have been exposed to a set of environmental conditions. It is known that environmental testing causes a decrease in shielding effectiveness when hexavalent chrome pretreatments are used (Alodine 1200s). Need to determine how shielding effectiveness will be affected with the use of hexavalent chrome free pretreatments. Performance will be assessed by evaluating shielding effectiveness (SE) test data from a variety of test samples comprised of different aluminum types and/or conversion coatings. The formation of corrosion will be evaluated between the mating surfaces and gasket to assess the corrosion resistant properties of the pretreatments, comparing the hexavalent control to the hexavalent chrome free pretreatments.

  13. A conceptual model for determining career choice of CHROME alumna based on farmer's conceptual models

    NASA Astrophysics Data System (ADS)

    Moore, Lisa Simmons

    This qualitative program evaluation examines the career decision-making processes and career choices of nine, African American women who participated in the Cooperating Hampton Roads Organization for Minorities in Engineering (CHROME) and who graduated from urban, rural or suburban high schools in the year 2000. The CHROME program is a nonprofit, pre-college intervention program that encourages underrepresented minority and female students to enter science, technically related, engineering, and math (STEM) career fields. The study describes career choices and decisions made by each participant over a five-year period since high school graduation. Data was collected through an Annual Report, Post High School Questionnaires, Environmental Support Questionnaires, Career Choice Questionnaires, Senior Reports, and standardized open-ended interviews. Data was analyzed using a model based on Helen C. Farmer's Conceptual Models, John Ogbu's Caste Theory and Feminist Theory. The CHROME program, based on its stated goals and tenets, was also analyzed against study findings. Findings indicated that participants received very low levels of support from counselors and teachers to pursue STEM careers and high levels of support from parents and family, the CHROME program and financial backing. Findings of this study also indicated that the majority of CHROME alumna persisted in STEM careers. The most successful participants, in terms of undergraduate degree completion and occupational prestige, were the African American women who remained single, experienced no critical incidents, came from a middle class to upper middle class socioeconomic background, and did not have children.

  14. Inline detection of Chrome degradation on binary 193nm photomasks

    NASA Astrophysics Data System (ADS)

    Dufaye, Félix; Sippel, Astrid; Wylie, Mark; García-Berríos, Edgardo; Crawford, Charles; Hess, Carl; Sartelli, Luca; Pogliani, Carlo; Miyashita, Hiroyuki; Gough, Stuart; Sundermann, Frank; Brochard, Christophe

    2013-09-01

    193nm binary photomasks are still used in the semiconductor industry for the lithography of some critical layers for the nodes 90nm and 65nm, with high volumes and over long periods. However, these 193nm binary photomasks can be impacted by a phenomenon of chrome oxidation leading to critical dimensions uniformity (CDU) degradation with a pronounced radial signature. If not detected early enough, this CDU degradation may cause defectivity issues and lower yield on wafers. Fortunately, a standard cleaning and repellicle service at the mask shop has been demonstrated as efficient to remove the grown materials and get the photomask CD back on target.Some detection methods have been already described in literature, such as wafer CD intrafield monitoring (ACLV), giving reliable results but also consuming additional SEM time with less precision than direct photomask measurement. In this paper, we propose another approach, by monitoring the CDU directly on the photomask, concurrently with defect inspection for regular requalification to production for wafer fabs. For this study, we focused on a Metal layer in a 90nm technology node. Wafers have been exposed with production conditions and then measured by SEM-CD. Afterwards, this photomask has been measured with a SEM-CD in mask shop and also inspected on a KLA-Tencor X5.2 inspection system, with pixels 125 and 90nm, to evaluate the Intensity based Critical Dimension Uniformity (iCDU) option. iCDU was firstly developed to provide feed-forward CDU maps for scanner intrafield corrections, from arrayed dense structures on memory photomasks. Due to layout complexity and differing feature types, CDU monitoring on logic photomasks used to pose unique challenges.The selection of suitable feature types for CDU monitoring on logic photomasks is no longer an issue, since the transmitted intensity map gives all the needed information, as shown in this paper. In this study, the photomask was heavily degraded after more than 18,000 300

  15. Efficient Nanostructured 'Black' Silicon Solar Cell by Copper-Catalyzed Metal-Assisted Etching

    SciTech Connect

    Toor, Fatima; Oh, Jihun; Branz, Howard M.

    2014-09-13

    Here, we produce low-reflectivity nanostructured ‘black’ silicon (bSi) using copper (Cu) nanoparticles as the catalyst for metal-assisted etching and demonstrate a 17.0%-efficient Cu-etched bSi solar cell without any vacuum-deposited anti-reflection coating. We found that the concentration ratio of HF to H2O2 in the etch solution provides control of the nanostructure morphology. The solar-spectrum-weighted average reflection (Rave) for bSi is as low as 3.1% on Cu-etched planar samples; we achieve lower reflectivity by nanostructuring of micron-scale pyramids. Successful Cu-based anti-reflection etching requires a concentration ratio [HF]/[H2O2] ≥ 3. Our 17.0%-efficient Cu-etched bSi photovoltaic cell with a pyramid-texture has a Rave of 3% and an open circuit voltage (Voc) of 616 mV that might be further improved by reducing near-surface phosphorus (P) densities.

  16. Development of a low-temperature, low-cost, black liquid solar collector. Phase II. Semi-annual report, September 1, 1979-February 29, 1980

    SciTech Connect

    Landstrom, D. K.; Talbert, S. G.; McGinniss, V. D.

    1980-03-20

    The research efforts during these first 6 months of Phase II have been directed toward (1) evaluating the long-term durability of various plastic materials and solar collector designs, (2) obtaining sufficient outdoor performance data to design a full-scale demonstration of a black-liquid solar collector for a commercial application, (3) teaming with a company willing to commercialize black liquid plastic collectors, and (4) incorporating improved black liquids with the identified plastic collector designs. Besides conducting indoor weathering tests of various plastic materials, two outdoor automated test facilities have been built. One unit has been in use for about 2 winter months at Battelle in Columbus, Ohio, and the other unit is ready for testing in Phoenix, Arizona, by Ramada Energy Systems, Inc., a collector manufacturing company. Since Ramada Energy Systems has been working with extruded polycarbonate panels, Battelle has been working to date with extruded acrylic panel designs. Other potential plastics for solar collectors will be evaluated later in this program.

  17. 40 CFR 425.10 - Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Applicability; description of the hair... FINISHING POINT SOURCE CATEGORY Hair Pulp, Chrome Tan, Retan-Wet Finish Subcategory § 425.10 Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory. The provisions of this subpart...

  18. 40 CFR 425.10 - Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Applicability; description of the hair... FINISHING POINT SOURCE CATEGORY Hair Pulp, Chrome Tan, Retan-Wet Finish Subcategory § 425.10 Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory. The provisions of this subpart...

  19. 40 CFR 425.20 - Applicability; description of the hair save, chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Applicability; description of the hair... FINISHING POINT SOURCE CATEGORY Hair Save, Chrome Tan, Retan-Wet Finish Subcategory § 425.20 Applicability; description of the hair save, chrome tan, retan-wet finish subcategory. The provisions of this subpart...

  20. 40 CFR 425.20 - Applicability; description of the hair save, chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Applicability; description of the hair... FINISHING POINT SOURCE CATEGORY Hair Save, Chrome Tan, Retan-Wet Finish Subcategory § 425.20 Applicability; description of the hair save, chrome tan, retan-wet finish subcategory. The provisions of this subpart...

  1. 40 CFR 425.20 - Applicability; description of the hair save, chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Applicability; description of the hair... FINISHING POINT SOURCE CATEGORY Hair Save, Chrome Tan, Retan-Wet Finish Subcategory § 425.20 Applicability; description of the hair save, chrome tan, retan-wet finish subcategory. The provisions of this subpart...

  2. 40 CFR 425.20 - Applicability; description of the hair save, chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the hair... POINT SOURCE CATEGORY Hair Save, Chrome Tan, Retan-Wet Finish Subcategory § 425.20 Applicability; description of the hair save, chrome tan, retan-wet finish subcategory. The provisions of this subpart...

  3. 40 CFR 425.10 - Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the hair... POINT SOURCE CATEGORY Hair Pulp, Chrome Tan, Retan-Wet Finish Subcategory § 425.10 Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory. The provisions of this subpart...

  4. 40 CFR 425.10 - Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Applicability; description of the hair... FINISHING POINT SOURCE CATEGORY Hair Pulp, Chrome Tan, Retan-Wet Finish Subcategory § 425.10 Applicability; description of the hair pulp, chrome tan, retan-wet finishing subcategory. The provisions of this subpart...

  5. Black light visualized solar lentigines on the shoulders and upper back are associated with objectively measured UVR exposure and cutaneous malignant melanoma.

    PubMed

    Idorn, Luise Winkel; Datta, Pameli; Heydenreich, Jakob; Philipsen, Peter Alshede; Wulf, Hans Christian

    2015-02-01

    Previous studies on the association of solar lentigines with ultraviolet radiation (UVR) exposure have been based on retrospective questionnaires about UVR exposure. We aimed to investigate the association between solar lentigines and UVR exposure in healthy individuals using objective measurements, and to investigate the association between solar lentigines and cutaneous malignant melanoma (CMM). Forty-eight patients with CMM and 48 controls that matched the patients individually by age, sex, constitutive skin type and occupation participated. Solar lentigines on the shoulders and upper back were counted and graded into 3 categories using black light photographs to show sun damage. Current UVR exposure in healthy controls was assessed by personal electronic UVR dosimeters that measured time-related UVR and by corresponding exposure diaries during a summer season. Sunburn history was assessed by interviews. Among controls, the number of solar lentigines was positively associated with daily hours spent outdoors between noon and 3 pm on holidays (P = 0.027), days at the beach (P = 0.048) and reported number of life sunburns (P < 0.001). Compared with matched controls CMM patients had a higher number of solar lentigines (P = 0.044). There was a positive association between CMM and higher solar lentigines grade; Category III versus Category I (P = 0.002) and Category II versus Category I (P = 0.014). Our findings indicate that solar lentigines in healthy individuals are associated with number of life sunburns, as well as time spent outdoors around noon on holidays and beach trips during a summer season, most likely reflecting past UVR exposure, and that solar lentigines are a risk factor for CMM.

  6. Enhanced solar energy absorption by internally-mixed black carbon in snow grains

    NASA Astrophysics Data System (ADS)

    Flanner, M. G.; Liu, X.; Zhou, C.; Penner, J. E.; Jiao, C.

    2012-05-01

    Here we explore light absorption by snowpack containing black carbon (BC) particles residing within ice grains. Basic considerations of particle volumes and BC/snow mass concentrations show that there are generally 0.05-109 BC particles for each ice grain. This suggests that internal BC is likely distributed as multiple inclusions within ice grains, and thus the dynamic effective medium approximation (DEMA) (Chýlek and Srivastava, 1983) is a more appropriate optical representation for BC/ice composites than coated-sphere or standard mixing approximations. DEMA calculations show that the 460 nm absorption cross-section of BC/ice composites, normalized to the mass of BC, is typically enhanced by factors of 1.8-2.1 relative to interstitial BC. BC effective radius is the dominant cause of variation in this enhancement, compared with ice grain size and BC volume fraction. We apply two atmospheric aerosol models that simulate interstitial and within-hydrometeor BC lifecycles. Although only ~2% of the atmospheric BC burden is cloud-borne, 71-83% of the BC deposited to global snow and sea-ice surfaces occurs within hydrometeors. Key processes responsible for within-snow BC deposition are development of hydrophilic coatings on BC, activation of liquid droplets, and subsequent snow formation through riming or ice nucleation by other species and aggregation/accretion of ice particles. Applying deposition fields from these aerosol models in offline snow and sea-ice simulations, we calculate that 32-73% of BC in global surface snow resides within ice grains. This fraction is smaller than the within-hydrometeor deposition fraction because meltwater flux preferentially removes internal BC, while sublimation and freezing within snowpack expose internal BC. Incorporating the DEMA into a global climate model, we simulate increases in BC/snow radiative forcing of 43-86%, relative to scenarios that apply external optical properties to all BC. We show that snow metamorphism driven by

  7. Enhanced Solar Energy Absorption by Internally-mixed Black Carbon in Snow Grains

    SciTech Connect

    Flanner, M. G.; Liu, Xiaohong; Zhou, Cheng; Penner, Joyce E.; Jiao, C.

    2012-05-30

    Here we explore light absorption by snowpack containing black carbon (BC) particles residing within ice grains. Basic considerations of particle volumes and BC/snow mass concentrations show that there are generally 0:05-109 BC particles for each ice grain. This suggests that internal BC is likely distributed as multiple inclusions within ice grains, and thus the dynamic effective medium approximation (DEMA) (Chylek and Srivastava, 1983) is a more appropriate optical representation for BC/ice composites than coated-sphere or standard mixing approximations. DEMA calculations show that the 460 nm absorption cross-section of BC/ice composites, normalized to the mass of BC, is typically enhanced by factors of 1.8-2.1 relative to interstitial BC. BC effective radius is the dominant cause of variation in this enhancement, compared with ice grain size and BC volume fraction. We apply two atmospheric aerosol models that simulate interstitial and within-hydrometeor BC lifecycles. Although only {approx}2% of the atmospheric BC burden is cloud-borne, 71-83% of the BC deposited to global snow and sea-ice surfaces occurs within hydrometeors. Key processes responsible for within-snow BC deposition are development of hydrophilic coatings on BC, activation of liquid droplets, and subsequent snow formation through riming or ice nucleation by other species and aggregation/accretion of ice particles. Applying deposition fields from these aerosol models in offline snow and sea-ice simulations, we calculate that 32-73% of BC in global surface snow resides within ice grains. This fraction is smaller than the within-hydrometeor deposition fraction because meltwater flux preferentially removes internal BC, while sublimation and freezing within snowpack expose internal BC. Incorporating the DEMA into a global climate model, we simulate increases in BC/snow radiative forcing of 43-86%, relative to scenarios that apply external optical properties to all BC. We show that snow metamorphism

  8. Composite films of carbon black nanoparticles and sulfonated-polythiophene as flexible counter electrodes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Li, Chun-Ting; Lee, Chi-Ta; Li, Sie-Rong; Lee, Chuan-Pei; Chiu, I.-Ting; Vittal, R.; Wu, Nae-Lih; Sun, Shih-Sheng; Ho, Kuo-Chuan

    2016-01-01

    A composite film based on carbon black nanoparticles and sulfonated-poly(thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-diyl) (CB-NPs/s-PT) is formed on a flexible titanium foil for the use as the electro-catalytic counter electrode (CE) of dye-sensitized solar cells (DSSCs). The CB-NPs provide the large amount of electro-catalytic active sites for the composite film, and the s-PT polymer serves as a conductive binder to enhance the inter-particle linkage among CB-NPs and to improve the adhesion between the composite film and the flexible substrate. The flexible CB-NPs/s-PT composite film is designed to possess good electro-catalytic ability for I-/I3- redox couple by providing large active sites and rapid reduction kinetic rate constant of I3- . The cell with a CB-NPs/s-PT CE exhibits a good cell efficiency (η) of 9.02 ± 0.01% at 100 mW cm-2, while the cell with a platinum CE shows an η of only 8.36 ± 0.02% under the same conditions. At weak light illuminations (20-80 mW cm-2), a DSSC with CB-NPs/s-PT CE still exhibits η's of 7.20 ± 0.04-9.08 ± 0.02%. The low-cost CB-NPs/s-PT CE not only renders high cell efficiency to its DSSC but also shows a great potential to replace the expensive platinum; moreover it is suitable for large-scale production or for indoor applications.

  9. CHROME: An Approach to Teaching the Concept of Inter-Functional Cooperation in Services Organizations

    ERIC Educational Resources Information Center

    Johnson, Lester W.

    2010-01-01

    When teaching a services course (e.g., Services Marketing) it is essential that students understand that marketing/management, operations and human resource management within the service organization be fully coordinated. One useful acronym used to remind students of this need is "CHROME", standing for Communications, Human Resources,…

  10. Enhanced photovoltaic performance of inverted pyramid-based nanostructured black-silicon solar cells passivated by an atomic-layer-deposited Al2O3 layer.

    PubMed

    Chen, Hong-Yan; Lu, Hong-Liang; Ren, Qing-Hua; Zhang, Yuan; Yang, Xiao-Feng; Ding, Shi-Jin; Zhang, David Wei

    2015-10-01

    Inverted pyramid-based nanostructured black-silicon (BS) solar cells with an Al2O3 passivation layer grown by atomic layer deposition (ALD) have been demonstrated. A multi-scale textured BS surface combining silicon nanowires (SiNWs) and inverted pyramids was obtained for the first time by lithography and metal catalyzed wet etching. The reflectance of the as-prepared BS surface was about 2% lower than that of the more commonly reported upright pyramid-based SiNW BS surface over the whole of the visible light spectrum, which led to a 1.7 mA cm(-2) increase in short circuit current density. Moreover, the as-prepared solar cells were further passivated by an ALD-Al2O3 layer. The effect of annealing temperature on the photovoltaic performance of the solar cells was investigated. It was found that the values of all solar cell parameters including short circuit current, open circuit voltage, and fill factor exhibit a further increase under an optimized annealing temperature. Minority carrier lifetime measurements indicate that the enhanced cell performance is due to the improved passivation quality of the Al2O3 layer after thermal annealing treatments. By combining these two refinements, the optimized SiNW BS solar cells achieved a maximum conversion efficiency enhancement of 7.6% compared to the cells with an upright pyramid-based SiNWs surface and conventional SiNx passivation.

  11. South Dakota School of Mines, Keystone, South Dakota solar-energy-system performanceevaluation, June 1980-April 1981

    SciTech Connect

    Eck, T.F.

    1981-01-01

    The South Dakota School of Mines site is the Mount Rushmore National Memorial Visitor's Center in Keystone, South Dakota. The active solar energy system is a retrofit designed to supply 45% of the heating load and 53% of the observation room cooling load. The system is equipped with 2000 square feet of flat-plate collector panels double-glazed with a black chrome absorber surface; 3000 gallons of water in an insulated tank for sensible heat storage; a two-stage fuel oil furnace for auxiliary heating; and direct expansion electric air conditioning units for auxiliary cooling. The actual heating and cooling provided are 42% and 12% respectively. The solar fraction, solar savings ratio, conventional fueld savings, electrical energy expense, system performance factor, and solar system coefficient of performance are among the performance data listed. A control problem is reported that kept the collector pump running 24 hours a day for 18 days. Performance data are given for each subsystem as well as for the overall system. Typical system operation and the system operating sequence for a day are given. The system's use of solar energy and the percentage of losses are given. Also included are a system description, performance evaluation techniques and equations, long-term weather data, chemical analysis of the antifreeze solutions, sensor technology, and typical weather and performance data for a month. (LEW)

  12. Exposure of eggs to solar UV-B leads to reduced hatching rates in two sparid fishes, red sea bream Pagrus major and black sea bream Acanthopagrus schlegeli.

    PubMed

    Fukunishi, Y; Masuda, R; Yamashita, Y

    2010-02-01

    Hatching success was examined under exposure to solar ultraviolet radiation (UVR) using filters to give three different light conditions [C1: UV-B, UV-A and photosynthetically active radiation (PAR), C2: UV-A and PAR, C3: PAR] in red Pagrus major and black Acanthopagrus schlegeli sea bream. Hatching rate of both species was reduced by an exposure over a 2 day period to UVR and was not significantly different between two species under the three light conditions. PMID:20666911

  13. A 15.65-solar-mass black hole in an eclipsing binary in the nearby spiral galaxy M 33.

    PubMed

    Orosz, Jerome A; McClintock, Jeffrey E; Narayan, Ramesh; Bailyn, Charles D; Hartman, Joel D; Macri, Lucas; Liu, Jiefeng; Pietsch, Wolfgang; Remillard, Ronald A; Shporer, Avi; Mazeh, Tsevi

    2007-10-18

    Stellar-mass black holes are found in X-ray-emitting binary systems, where their mass can be determined from the dynamics of their companion stars. Models of stellar evolution have difficulty producing black holes in close binaries with masses more than ten times that of the Sun (>10; ref. 4), which is consistent with the fact that the most massive stellar black holes known so far all have masses within one standard deviation of 10. Here we report a mass of (15.65 +/- 1.45) for the black hole in the recently discovered system M 33 X-7, which is located in the nearby galaxy Messier 33 (M 33) and is the only known black hole that is in an eclipsing binary. To produce such a massive black hole, the progenitor star must have retained much of its outer envelope until after helium fusion in the core was completed. On the other hand, in order for the black hole to be in its present 3.45-day orbit about its (70.0 +/- 6.9) companion, there must have been a 'common envelope' phase of evolution in which a significant amount of mass was lost from the system. We find that the common envelope phase could not have occurred in M 33 X-7 unless the amount of mass lost from the progenitor during its evolution was an order of magnitude less than what is usually assumed in evolutionary models of massive stars. PMID:17943124

  14. A 15.65-solar-mass black hole in an eclipsing binary in the nearby spiral galaxy M 33.

    PubMed

    Orosz, Jerome A; McClintock, Jeffrey E; Narayan, Ramesh; Bailyn, Charles D; Hartman, Joel D; Macri, Lucas; Liu, Jiefeng; Pietsch, Wolfgang; Remillard, Ronald A; Shporer, Avi; Mazeh, Tsevi

    2007-10-18

    Stellar-mass black holes are found in X-ray-emitting binary systems, where their mass can be determined from the dynamics of their companion stars. Models of stellar evolution have difficulty producing black holes in close binaries with masses more than ten times that of the Sun (>10; ref. 4), which is consistent with the fact that the most massive stellar black holes known so far all have masses within one standard deviation of 10. Here we report a mass of (15.65 +/- 1.45) for the black hole in the recently discovered system M 33 X-7, which is located in the nearby galaxy Messier 33 (M 33) and is the only known black hole that is in an eclipsing binary. To produce such a massive black hole, the progenitor star must have retained much of its outer envelope until after helium fusion in the core was completed. On the other hand, in order for the black hole to be in its present 3.45-day orbit about its (70.0 +/- 6.9) companion, there must have been a 'common envelope' phase of evolution in which a significant amount of mass was lost from the system. We find that the common envelope phase could not have occurred in M 33 X-7 unless the amount of mass lost from the progenitor during its evolution was an order of magnitude less than what is usually assumed in evolutionary models of massive stars.

  15. 40 CFR 425.20 - Applicability; description of the hair save, chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS LEATHER TANNING AND FINISHING... cattle-like hides into finished leather by hair save unhairing, chrome tanning, and retan-wet finishing....

  16. Astrophysics: Monster black holes

    NASA Astrophysics Data System (ADS)

    Cappellari, Michele

    2011-12-01

    A combination of ground-based and spacecraft observations has uncovered two black holes of 10 billion solar masses in the nearby Universe. The finding sheds light on how these cosmic monsters co-evolve with galaxies.

  17. Patients with metal-on-metal articulation in trapeziometacarpal total joint arthroplasty may have elevated serum chrome and cobalt.

    PubMed

    Hansen, T B; Dremstrup, L; Stilling, M

    2013-10-01

    Serum chrome and cobalt was measured in 50 patients with trapeziometacarpal total joint replacement with metal-on-metal articulation and compared with serum chrome and cobalt values in 23 patients with trapeziometacarpal total joint replacement with metal-on-polyethylene articulation. In 10 of 50 (20%) patients with metal-on-metal articulation, slightly elevated serum chrome or cobalt values were found compared with only one in 23 (4%) patients with metal-on-polyethylene articulation. All metal values were lower than accepted 'normal values' for metal-on-metal hip arthroplasty and so considered not to be a general health risk. However, the mean disabilities of the arm, shoulder and hand (DASH) score was 24 in patients with elevated serum chrome or cobalt compared with 10 in patients with normal metal values (p < 0.05) suggesting a local clinical effect of the elevated serum chrome or cobalt values. We recommend that patients with trapeziometacarpal total joint replacement with metal-on-metal articulation are followed with DASH score and radiological examination every 3-5 years and serum chrome and cobalt should be analysed in symptomatic cases to learn more about possible local complications leading to, or arising from, metal debris.

  18. Deposition of Hard Chrome Coating onto Heat Susceptible Substrates by Low Power Microwave Plasma Spray

    NASA Astrophysics Data System (ADS)

    Redza, Ahmad; Yasui, Toshiaki; Fukumoto, Masahiro

    2016-02-01

    Microwave plasma spray requires relatively low power, which is lower than 1 kW in comparison to other plasma spraying method. Until now, we are able to deposit Cu and Hydroxyapatite coating onto heat susceptible substrate, CFRP which are difficult for conventional plasma spray due to the excessive heat input. In this paper, a hard chromium coating was deposited onto SUS304 and CFRP by a low power microwave plasma spray technique. By controlling the working gas flow rate and spraying distance, a hard chrome coating with thickness of approximately 30 μm was successfully deposited onto CFRP substrate with hardness of 1110 Hv0.05. Furthermore, the coating produced here is higher than that produced by hard chrome plating.

  19. NASA and ESA Collaboration on Hexavalent Chrome Alternatives: Pretreatments Only Final Test Report

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2015-01-01

    Hexavalent chromium (hex chrome or CR(VI)) is a widely used element within applied coating systems because of its self-healing and corrosion-resistant properties. The replacement of hex chrome in the processing of aluminum for aviation and aerospace applications remains a goal of great significance. Aluminum is the major manufacturing material of structures and components in the space flight arena. The National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) are engaged in a collaborative effort to test and evaluate alternatives to hexavalent chromium containing corrosion coating systems. NASA and ESA share common risks related to material obsolescence associated with hexavalent chromium used in corrosion-resistant coatings.

  20. A simple method for the use of gallocyanin-chrome alum as an electron strain.

    PubMed

    Sandritter, W; Riede, U; Kiefer, G

    1981-03-01

    A method has been elaborated for the demonstration of DNA in the electron microscope. The method uses glutaraldehyde fixed tissue pieces from which RNA has been removed by incubation with RNase. DNA is stained by gallocyanin-chrome alum in the tissue block. Embedding and cutting is done in the usual manner. The method is based on histochemical observations at the light microscope level which show sufficient specificity and a good stoichiometry of the staining reaction.

  1. Chemometrics models for assessment of oxidative stress risk in chrome-electroplating workers.

    PubMed

    Zendehdel, Rezvan; Shetab-Boushehri, Seyed Vahid; Azari, Mansoor R; Hosseini, Vajihe; Mohammadi, Hamidreza

    2015-04-01

    Oxidative stress is the main cause of hexavalant chromium-induced damage in chrome electroplating workers. The main goal of this study is toxicity analysis and the possibility of toxicity risk categorizing in the chrome electroplating workers based on oxidative stress parameters as prognostic variables. We assessed blood chromium levels and biomarkers of oxidative stress such as lipid peroxidation, thiol (SH) groups and antioxidant capacity of plasma. Data were subjected to principle component analysis (PCA) and artificial neuronal network (ANN) to obtain oxidative stress pattern for chrome electroplating workers. Blood chromium levels increased from 4.42 ppb to 10.6 ppb. Induction of oxidative stress was observed by increased in lipid peroxidation (22.38 ± 10.47 μM versus 14.74 ± 4.82 μM, p < 0.0008), decreased plasma antioxidant capacity (3.17 ± 1.35 μM versus 7.74 ± 4.45 μM, p < 0.0001) and plasma total thiol (SH groups) (0.21 ± 0.07 μM versus 0.45 ± 0.41 μM, p < 0.0042) in comparison to controls. Based on the oxidative parameters, two groups were identified by PCA methods. One category is workers with the risk of oxidative stress and second group is subjects with probable risk of oxidative stress induction. ANN methods can predict oxidative-risk category for assessment of toxicity induction in chrome electroplaters. The result showed multivariate modeling can be interpreted as the induced biochemical toxicity in the workers exposed to hexavalent chromium. Different occupation groups were assessed on the basis of risk level of oxidative stress which could further justify proceeding engineering control measures.

  2. A simple method for the use of gallocyanin-chrome alum as an electron strain.

    PubMed

    Sandritter, W; Riede, U; Kiefer, G

    1981-03-01

    A method has been elaborated for the demonstration of DNA in the electron microscope. The method uses glutaraldehyde fixed tissue pieces from which RNA has been removed by incubation with RNase. DNA is stained by gallocyanin-chrome alum in the tissue block. Embedding and cutting is done in the usual manner. The method is based on histochemical observations at the light microscope level which show sufficient specificity and a good stoichiometry of the staining reaction. PMID:6163861

  3. Comparative statistical analysis of chrome and vegetable tanning effluents and their effects on related soil.

    PubMed

    Tariq, Saadia R; Shah, Munir H; Shaheen, Nazia

    2009-09-30

    Two tanning units of Pakistan, namely, Kasur and Mian Channun were investigated with respect to the tanning processes (chrome and vegetable, respectively) and the effects of the tanning agents on the quality of soil in vicinity of tanneries were evaluated. The effluent and soil samples from 16 tanneries each of Kasur and Mian Channun were collected. The levels of selected metals (Na, K, Ca, Mg, Fe, Cr, Mn, Co, Cd, Ni, Pb and Zn) were determined by using flame atomic absorption spectrophotometer under optimum analytical conditions. The data thus obtained were subjected to univariate and multivariate statistical analyses. Most of the metals exhibited considerably higher concentrations in the effluents and soils of Kasur compared with those of Mian Channun. It was observed that the soil of Kasur was highly contaminated by Na, K, Ca and Mg emanating from various processes of leather manufacture. Furthermore, the levels of Cr were also present at much enhanced levels than its background concentration due to the adoption of chrome tanning. The levels of Cr determined in soil samples collected from the vicinity of Mian Channun tanneries were almost comparable to the background levels. The soil of this city was found to have contaminated only by the metals originating from pre-tanning processes. The apportionment of selected metals in the effluent and soil samples was determined by a multivariate cluster analysis, which revealed significant differences in chrome and vegetable tanning processes.

  4. High temperature brush seal tuft testing of metallic bristles versus chrome carbide

    NASA Technical Reports Server (NTRS)

    Fellenstein, James A.; DellaCorte, Christopher; Moore, Kenneth D.; Boyes, Esther

    1996-01-01

    The tribology of brush seals is of considerable interest to turbine engine designers because bristle wear continues to limit long term seal performance and life. To provide better materials characterization and foster the development of improved seals, NASA Lewis has developed a brush seal tuft tester. In this test, a 'paintbrush' sample tuft is loaded under constant contact pressure against the outside diameter of a rotating journal. With this configuration a direct measurement of load and friction is made. Accurate wear rate measurements are possible due to the known contact pressure. Previously reported baseline research using this facility showed good data repeatability and wear morphology similar to published seal data. This paper extends and expands the database for candidate brush seal materials. A series of tuft tests were completed to evaluate the performance of five high temperature superalloy wires sliding against plasma sprayed nichrome-bonded chrome carbide. Wire materials were either nickel-chrome or cobalt-chrome based superalloys. Good corroboration of the tuft results with dynamic seal rig tests was observed; giving additional confidence in the tuft test as a screening and development tool.

  5. Efficiency Enhancement of Nanotextured Black Silicon Solar Cells Using Al2O3/TiO2 Dual-Layer Passivation Stack Prepared by Atomic Layer Deposition.

    PubMed

    Wang, Wei-Cheng; Tsai, Meng-Chen; Yang, Jason; Hsu, Chuck; Chen, Miin-Jang

    2015-05-20

    In this study, efficient nanotextured black silicon (NBSi) solar cells composed of silicon nanowire arrays and an Al2O3/TiO2 dual-layer passivation stack on the n(+) emitter were fabricated. The highly conformal Al2O3 and TiO2 surface passivation layers were deposited on the high-aspect-ratio surface of the NBSi wafers using atomic layer deposition. Instead of the single Al2O3 passivation layer with a negative oxide charge density, the Al2O3/TiO2 dual-layer passivation stack treated with forming gas annealing provides a high positive oxide charge density and a low interfacial state density, which are essential for the effective field-effect and chemical passivation of the n(+) emitter. In addition, the Al2O3/TiO2 dual-layer passivation stack suppresses the total reflectance over a broad range of wavelengths (400-1000 nm). Therefore, with the Al2O3/TiO2 dual-layer passivation stack, the short-circuit current density and efficiency of the NBSi solar cell were increased by 11% and 20%, respectively. In conclusion, a high efficiency of 18.5% was achieved with the NBSi solar cells by using the n(+)-emitter/p-base structure passivated with the Al2O3/TiO2 stack.

  6. Efficiency Enhancement of Nanotextured Black Silicon Solar Cells Using Al2O3/TiO2 Dual-Layer Passivation Stack Prepared by Atomic Layer Deposition.

    PubMed

    Wang, Wei-Cheng; Tsai, Meng-Chen; Yang, Jason; Hsu, Chuck; Chen, Miin-Jang

    2015-05-20

    In this study, efficient nanotextured black silicon (NBSi) solar cells composed of silicon nanowire arrays and an Al2O3/TiO2 dual-layer passivation stack on the n(+) emitter were fabricated. The highly conformal Al2O3 and TiO2 surface passivation layers were deposited on the high-aspect-ratio surface of the NBSi wafers using atomic layer deposition. Instead of the single Al2O3 passivation layer with a negative oxide charge density, the Al2O3/TiO2 dual-layer passivation stack treated with forming gas annealing provides a high positive oxide charge density and a low interfacial state density, which are essential for the effective field-effect and chemical passivation of the n(+) emitter. In addition, the Al2O3/TiO2 dual-layer passivation stack suppresses the total reflectance over a broad range of wavelengths (400-1000 nm). Therefore, with the Al2O3/TiO2 dual-layer passivation stack, the short-circuit current density and efficiency of the NBSi solar cell were increased by 11% and 20%, respectively. In conclusion, a high efficiency of 18.5% was achieved with the NBSi solar cells by using the n(+)-emitter/p-base structure passivated with the Al2O3/TiO2 stack. PMID:25919200

  7. Enhancement of Efficiency of a Solar Cell Fabricated on Black Si Made by Inductively Coupled Plasma-Reactive Ion Etching Process: A Case Study of a n-CdS/p-Si Heterojunction Cell.

    PubMed

    Katiyar, Ajit K; Mukherjee, S; Zeeshan, M; Ray, Samit K; Raychaudhuri, A K

    2015-10-28

    We show that a significant enhancement of solar cell efficiency can be achieved in cells fabricated on black Si made using inductively coupled plasma-reactive ion etching (ICP-RIE). The ICP-RIE-fabricated black Si results in an array of vertically oriented defect-free Si nanocones (average height ∼150 nm; apex diameter ∼25 nm) exhibiting an average reflectance ≤2% over most of the relevant solar spectral range. The enabling role of the ultralow reflectance of the nanostructured black Si has been demonstrated using a heterojunction solar cell fabricated by depositing a n-type CdS film on p-Si nanocones followed by a transparent conducting coating of Al-doped ZnO (AZO). The fabricated n-CdS/p-Si heterojunction exhibits promising power conversion efficiency close to 3%, up from a mere efficient 0.15% for a similar cell fabricated on a planar Si. The effect of the fabrication process for the black Si on solar cell performance has been investigated through the measurements of carrier lifetime and surface recombination velocity. The accompanying model and simulation analysis shows that the conical structure leads to the effective dielectric constant varying smoothly from the value of the air at the top to the value of Si at the base over the length of the nanocone, leading to a substantial reduction of its reflectance.

  8. Low-mass black holes as the remnants of primordial black hole formation

    NASA Astrophysics Data System (ADS)

    Greene, Jenny E.

    2012-12-01

    Bridging the gap between the approximately ten solar mass `stellar mass' black holes and the `supermassive' black holes of millions to billions of solar masses are the elusive `intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ~104-105Msolar black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

  9. Photocatalytic degradation of the diazo dye naphthol blue black in water using MWCNT/Gd,N,S-TiO2 nanocomposites under simulated solar light.

    PubMed

    Mamba, Gcina; Mbianda, Xavier Yangkou; Mishra, Ajay Kumar

    2015-07-01

    A simple sol-gel method was employed to prepare gadolinium, nitrogen and sulphur tridoped titania decorated on oxidised multiwalled carbon nanotubes (MWCNT/Gd,N,S-TiO2), using titanium (IV) butoxide and thiourea as titanium and nitrogen and sulphur source, respectively. Samples of varying gadolinium loadings (0.2%, 0.6%, 1.0% and 3.0% Gd3+) relative to titania were prepared to investigate the effect of gadolinium loading and the amounts of carbon nanotubes, nitrogen and sulphur were kept constant for all the samples. Furthermore, the prepared nanocomposites were evaluated for the degradation of naphthol blue black (NBB) in water under simulated solar light irradiation. Higher degradation efficiency (95.7%) was recorded for the MWCNT/Gd,N,S-TiO2 (0.6% Gd) nanocomposites. The higher photocatalytic activity is attributed to the combined effect of improved visible light absorption and charge separation due to the synergistic effect of Gd, MWCNTs, N, S and TiO2. Total organic carbon (TOC) analysis revealed a higher degree of complete mineralisation of naphthol blue black (78.0% TOC removal) which minimises the possible formation of toxic degradation by-products such as the aromatic amines. The MWCNT/Gd,N,S-TiO2 (0.6% Gd) was fairly stable and could be re-used for five times, reaching a maximum degradation efficiency of 91.8% after the five cycles.

  10. Improved in situ hybridization and G-banding by pretreatment with Denhardt's solution and gelatin-chrome alum.

    PubMed

    Lee, G M; Rasch, E M; Musich, P R

    1985-11-01

    Various pretreatments of metaphase spreads were examined to obtain optimal DNA labelling patterns while maintaining chromosome integrity during in situ hybridization procedures. Preparations of African green monkey (AGM) chromosomes fixed in methanol-acetic acid (CV-1 cell line) were treated by coating with Denhardt's solution, dilute gelatin-chrome alum, nonfat instant dry milk dissolved in saline-citrate solution (SSC) and/or acetylation prior to denaturation of chromosomal DNA in 70% formamide-2 X SSC for 2 min at 70 degrees C. A 3H-labelled, cloned DNA fragment of the highly repetitive AGM component alpha DNA was hybridized to the chromosomes by incubation at 45 degrees C for 16 h. Treatment with gelatin-chrome alum prior to denaturation greatly improved chromosome morphology and decreased background, but reduced pericentromeric labelling. Sequential treatment with 5 X Denhardt's solution followed by gelatin-chrome alum resulted in enhanced specificity of labelling and excellent chromosome morphology, as well as reduced levels of background. Acetylation had little effect after pretreatment with gelatin-chrome alum, but reduced background levels after pretreatment with Denhardt's solution. Chromosomes treated with Denhardt's solution plus gelatin-chrome alum can be routinely G-banded using trypsin after in situ hybridization.

  11. A mathematical model of ionic transport in a porous diaphragm of a chrome-alum cell

    NASA Astrophysics Data System (ADS)

    Vidal, Roberto; Duby, Paul; West, Alan C.

    1994-06-01

    A model of the homogeneous chemistry and transport processes within the separator of a chrome-alum electrowinning cell is introduced, discussed, and compared to experiment. The influences of diffusion, electromigration, and convection are included; it is found that convection was the dominant mode of transport for the experimental conditions. Simulation results explain experimental observations concerning an apparent disappearance of dichromate ions produced at the cell anode. The relation between potential drop across the diaphragm and the current and fluid flow is also illustrated. The model is used to recommend future experimental and theoretical work.

  12. Evacuated tubular solar collector with internal reflector and heatpipe

    SciTech Connect

    Imani, K.; Ikeda, N.; Sumida, I.

    1983-12-01

    An evacuated tubular solar collector, was developed to provide 130/sup 0/C water for an industrial system. The collector consisted of 6 glass-tubes (100 mm O.D.), the internal silver ion-plated reflector, and copper heatpipes coated by the chrome-black selective absorber. The absorptance and the emittance of the absorber was measured to be 95% and 12%, respectively. The cross-section of reflector was composed of involute curve, straight line and envelope curve. The straight line was used to widen the aperture of reflector, and the envelope curve was designed to focus the 30/sup 0/ incident light on the heatpipe surface. The acceptance angle, concentration ratio and reflectivity was 60/sup 0/, 1.3, and 93%, respectively. The tip of heatpipe, which east side was horizontally 0.7/sup 0/ declined, was bent upwards to accommodate the freezing space to working fluid of 100 cm/sup 3/ water. The west side of heatpipe (22.22 mm O.D.) was connected to the coaxial heat exchanger with the internal fins. The effective colletor area was 1.43 m/sup 2/, while the total installation area was 1.92 m/sup 2/ (2.86m X 0.67m).

  13. Soybean plant growth study conducted using purified protein hydrolysate-based fertilizer made from chrome-tanned leather waste.

    PubMed

    Pati, Anupama; Chaudhary, Rubina

    2015-12-01

    Leather processing discharges enormous amount of chrome containing leather solid waste which creates a major disposal problem. Chrome-tanned leather solid waste is a complex of collagen and chromium. The presence of chromium limits protein application in fertilizer industry. The purified protein hydrolysate with zero chromium could be used as a nitrogen source for fertilizer formulation. In this study, an attempt has been made to employ purified protein hydrolysate derived from chrome-tanned leather shavings (CTLS) in formulation of fertilizer. The formulated fertilizer (1–3 t ha(-1)) is employed as nitrogen source in production of soybean. Plant growth study demonstrates that formulated fertilizer dosage 3 t ha(-1) produced similar effects of commercial fertilizer-treated plants. Application of formulated fertilizer yielded higher seed in plant than commercial fertilizer.

  14. CORROSION STUDY FOR THE EFFLUENT TREATMENT FACILITY (ETF) CHROME (VI) REDUCTANT SOLUTION USING 304 & 316L STAINLESS STEEL

    SciTech Connect

    DUNCAN, J.B.

    2007-06-27

    The Effluent Treatment Facility has developed a method to regenerate spent resin from the groundwater pump and treat intercepting chrome(VI) plumes (RPP-RPT-32207, Laboratory Study on Regeneration of Spent DOWEX 21K 16-20 Mesh Ion Exchange Resin). Subsequent laboratory studies have shown that the chrome(VI) may be reduced to chrome(III) by titrating with sodium metabisulfite to an oxidation reduction potential (ORP) of +280 mV at a pH of 2. This test plan describes the use of cyclic potentiodynamic polarization and linear polarization techniques to ascertain the electrochemical corrosion and pitting propensity of the 304 and 316L stainless steel in the acidified reducing the solution that will be contained in either the secondary waste receiver tank or concentrate tank.

  15. 40 CFR 425.30 - Applicability; description of the hair save or pulp, non-chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Applicability; description of the hair... TANNING AND FINISHING POINT SOURCE CATEGORY Hair Save or Pulp, Non-Chrome Tan, Retan-Wet Finish Subcategory § 425.30 Applicability; description of the hair save or pulp, non-chrome tan, retan-wet...

  16. 40 CFR 425.30 - Applicability; description of the hair save or pulp, non-chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Applicability; description of the hair... TANNING AND FINISHING POINT SOURCE CATEGORY Hair Save or Pulp, Non-Chrome Tan, Retan-Wet Finish Subcategory § 425.30 Applicability; description of the hair save or pulp, non-chrome tan, retan-wet...

  17. 40 CFR 425.30 - Applicability; description of the hair save or pulp, non-chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Applicability; description of the hair... TANNING AND FINISHING POINT SOURCE CATEGORY Hair Save or Pulp, Non-Chrome Tan, Retan-Wet Finish Subcategory § 425.30 Applicability; description of the hair save or pulp, non-chrome tan, retan-wet...

  18. Environmental impact studies of Chrome rollers used by cotton roller ginning industries and design and development of pollution free chromeless RCF rollers.

    PubMed

    Singh, Gurdeep; Iyer, G Vijayan

    2004-01-01

    This study focuses on environmental chromium contamination and pollution caused by the use of Chrome Composite Leather-Clad (CCLC) rollers commonly used in cotton roller ginning industries and attempts to eliminate this problem by providing eco-friendly chrome-less rollers.

  19. 40 CFR 425.30 - Applicability; description of the hair save or pulp, non-chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the hair... FINISHING POINT SOURCE CATEGORY Hair Save or Pulp, Non-Chrome Tan, Retan-Wet Finish Subcategory § 425.30 Applicability; description of the hair save or pulp, non-chrome tan, retan-wet finish subcategory....

  20. 40 CFR 425.30 - Applicability; description of the hair save or pulp, non-chrome tan, retan-wet finish subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the hair... FINISHING POINT SOURCE CATEGORY Hair Save or Pulp, Non-Chrome Tan, Retan-Wet Finish Subcategory § 425.30 Applicability; description of the hair save or pulp, non-chrome tan, retan-wet finish subcategory....

  1. Infrared, spectral, directional-hemispherical reflectance of fused silica, Teflon polytetrafluoroethylene polymer, chrome oxide ceramic particle surface, Pyromark 2500 paint, Krylon 1602 paint, and Duraflect coating

    NASA Astrophysics Data System (ADS)

    Persky, Merle J.; Szczesniak, Martin

    2008-04-01

    Infrared, spectral, directional-hemispherical reflectivity measurements of polished fused silica, Teflon polytetrafluoroethylene polymer, chrome oxide ceramic particle surface, Pyromark 2500 paint, Krylon 1602 paint, and Duraflect coating are provided. The reflectance was measured with an estimated accuracy of 0.01 to 0.02 units and a precision of 0.005 units. All the surfaces were measured at ambient temperatures. Additionally, the chrome oxide ceramic particle surface was measured at 486 K and the Pyromark 2500 at four temperatures to 877 K. Polarization measurements are also provided for fused silica, Duraflect, chrome oxide ceramic particle surface, and Pyromark 2500 paint. Separate diffuse and specular reflectance components for the Duraflect and chrome oxide ceramic surfaces are included. Fresnel-based predictions for fused silica parallel and perpendicular polarized reflections are compared to measurements. It is notable that the Pyromark 2500 and chrome oxide ceramic particle surfaces exhibit a significant lack of manufacturing repeatability.

  2. Radiation induced graft copolymerization of methyl methacrylate onto chrome-tanned pig skins

    NASA Astrophysics Data System (ADS)

    Pietrucha, K.; Pȩkala, W.; Kroh, J.

    Graft copolymerization of methyl methacrylate (MMA) onto chrome-tanned pig skins was carried out by the irradiation with 60Co ?-rays. The grafted polymethyl methacrylate (PMMA) chains were isolated by acid hydrolysis of the collagen backbone in order to characterize the graft copolymers. Proof of grafting was obtained through the detection of amino acid endgroups in the isolated grafts by reaction with ninhydrin. The grafting yield of MMA in aqueous emulsion was found to be higher than that for pure MMA and MMA in acetone. The degree of grafting increases with increasing monomer concentration in emulsion and reaches maximum at radiation dose ca 15 kGy. The yield of grafting is very high - ca 90% of monomer converts into copolymer and only 10% is converted into homopolymer. The present paper reports the physical properties of chrome-tanned pig skins after graft polymerization with MMA in emulsion. Modified leathers are more resistant against water absorption and abrasion in comparison with unmodified ones. They have more uniform structure over the whole surface, greater thickness and stiffness. The results reported seem to indicate that MMA may be used in the production of shoe upper and sole leathers. The mechanism of some of the processes occuring during radiation grafting of MMA in water emulsion on tanned leathers has been also suggested and discussed.

  3. EVIDENCE FOR HIGH-FREQUENCY QPOs WITH A 3:2 FREQUENCY RATIO FROM A 5000 SOLAR MASS BLACK HOLE

    SciTech Connect

    Pasham, Dheeraj R.; Cenko, S. Bradley; Mushotzky, Richard F.; Tombesi, Francesco; Zoghbi, Abderahmen; Miller, Jon E-mail: brad.cenko@nasa.gov E-mail: richard@astro.umd.edu E-mail: jonmm@umich.edu

    2015-09-20

    Following the discovery of 3:2 resonance quasi-periodic oscillations (QPOs) in M82X-1, we have constructed power density spectra (PDS) of all 15 (sufficiently long) XMM-Newton observations of the ultraluminous X-ray source NGC 1313 X-1 (L{sub X} ≈ 2 × 10{sup 40} erg s{sup −1}). We detect a strong QPO at a frequency of 0.29 ± 0.01 Hz in data obtained on 2012 December 16. Subsequent searching of all the remaining observations for a 3:2/2:3 frequency pair revealed a feature at 0.46 ± 0.02 Hz on 2003 December 13 (frequency ratio of 1.59 ± 0.09). The global significance of the 0.29 Hz feature considering all frequencies between 0.1 and 4 Hz is >3.5σ. The significance of the 0.46 ± 0.02 Hz QPO is >3.5σ for a search at 2/3 and 3/2 of 0.29 Hz. We also detect lower-frequency QPOs (32.9 ± 2.6 and 79.7 ± 1.2 mHz). All the QPOs are superimposed on a continuum consisting of flat-topped, band-limited noise, breaking into a power law at a frequency of 16 ± 3 mHz and white noise at ≳0.1 Hz. NGC 1313 X-1's PDS is analogous to stellar-mass black holes’ (StMBHs) PDS in the so-called steep power-law state, but with the respective frequencies (both QPOs and break frequencies) scaled down by a factor of ∼1000. Using the inverse mass-to-high-frequency QPO scaling of StMBHs, we estimate NGC 1313 X-1's black hole mass to be 5000 ± 1300 M{sub ⊙}, consistent with an inference from the scaling of the break frequency. However, the implied Eddington ratio, L{sub Edd} > 0.03 ± 0.01, is significantly lower compared to that of StMBHs in the steep power-law state (L{sub Edd} ≳ 0.2)

  4. Reflection contrast microscopy within chrome-alum haematoxylin stained thick tissue-sections.

    PubMed

    Filler, T J; Rickert, C H; Fassnacht, U K; Pera, F

    1994-06-01

    This paper introduces two innovations in reflection contrast microscopy (RCM): (1) an extended application for qualitative light microscopic investigations; and (2) a novel method for quantification in cytochemistry. (1) We found out that RCM cannot only be used for surface characterizations and in thin sections but also within thick tissue-sections. The use of the RCM technique is demonstrated on slides of the supraoptic nucleus (SON) of the rat stained with chrome-alum haematoxylin: Among all the stained structures only neurosecretory granules are found to cause reflections. The visualization of the neurosecretion and its distribution is more distinct and of sharper contrast than in bright field microscopy. (2) The improved differentiation allows the quantification of neurosecretion in tissue-sections by combining RCM with grey-scale image analysis.

  5. Detection and differentiation of microbial siderophores by isoelectric focusing and chrome azurol S overlay.

    PubMed

    Koedam, N; Wittouck, E; Gaballa, A; Gillis, A; Höfte, M; Cornelis, P

    1994-10-01

    Siderophores are microbial, low molecular weight iron-chelating compounds. Fluorescent Pseudomonads produce different, strain-specific fluorescent siderophores (pyoverdines) as well as non-fluorescent siderophores in response to low iron conditions. We present an isoelectric focusing method applicable to unpurified as well as to purified pyoverdine samples where the fluorescent siderophores are visualized under UV illumination. Siderophores from different Pseudomonas sp., amongst which are P. aeruginosa, P. fluorescens and P. putida, including egg yolk, rhizospheric and clinical isolates as well as some derived Tn5 mutants were separated by this technique. Different patterns could be observed for strains known to produce different siderophores. The application of the chrome azurol S assay as a gel overlay further allows immediate detection of non-fluorescent siderophores or possibly degradation products with residual siderophore activity. The method was also applied to other microbial siderophores such as deferrioxamine B. PMID:7812113

  6. Studying the effects of modified surface chemistry on chrome migration in binary photomasks

    NASA Astrophysics Data System (ADS)

    Kossow, Christopher; Kirlin, Peter; Green, Michael

    2013-09-01

    Migration of the Cr/CrxOy film in binary photomasks during use in 193nm photolithography has been observed for some time in the semiconductor industry. This phenomenon leads to a shift in the reticle critical dimensions (CDs) that worsen with increased exposure eventually resulting in wafer yield loss. This paper studies the impact of varying annealing conditions on the CrxOy species on the surface of the mask. Further, we examined the effect of a surface condition with maximized Cr2O3 content on the 193nm-induced chrome migration phenomenon. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-Ray Photoelectron Spectroscopy (XPS) were used to characterize the composition of the Cr/CrxOy film. A 193nm accelerated exposure test bench was used to induce film migration in samples of varying surface chemistry.

  7. Enhancing Surface Finish of Additively Manufactured Titanium and Cobalt Chrome Elements Using Laser Based Finishing

    NASA Astrophysics Data System (ADS)

    Gora, Wojciech S.; Tian, Yingtao; Cabo, Aldara Pan; Ardron, Marcus; Maier, Robert R. J.; Prangnell, Philip; Weston, Nicholas J.; Hand, Duncan P.

    Additive manufacturing (AM) offers the possibility of creating a complex free form object as a single element, which is not possible using traditional mechanical machining. Unfortunately the typically rough surface finish of additively manufactured parts is unsuitable for many applications. As a result AM parts must be post-processed; typically mechanically machined and/or and polished using either chemical or mechanical techniques (both of which have their limitations). Laser based polishing is based on remelting of a very thin surface layer and it offers potential as a highly repeatable, higher speed process capable of selective area polishing, and without any waste problems (no abrasives or liquids). In this paper an in-depth investigation of CW laser polishing of titanium and cobalt chrome AM elements is presented. The impact of different scanning strategies, laser parameters and initial surface condition on the achieved surface finish is evaluated.

  8. Comparison of back side chrome focus monitor to focus self-metrology of an immersion scanner

    NASA Astrophysics Data System (ADS)

    D'havé, Koen; Machida, Takahiro; Laidler, David; Cheng, Shaunee

    2007-03-01

    Monitoring of the focus performance is recognized to be an important part of a periodic scanner health check, but can one simply apply all techniques that have been used for dry scanners to immersion scanners? And if so how do such techniques compare to scanner self-metrology tests that are used to set up the tool? In this paper we look at one specific off-line focus characterization technique, Back Side Chrome (BSC), which we then try to match with results obtained from two self-metrology focus tests, available on the scanner chosen for this work. The latter tests are also used to set up the immersion scanner. We point out a few concerns, discuss their effect and indicate that for each generation of immersion tool one should redo the entire exercise.

  9. NASA and ESA Collaboration on Hexavalent Chrome Alternatives Pretreatments Only Interim Test Report

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2015-01-01

    NASA and ESA continue to search for an alternative to hexavalent chromium in coatings applications that meet their performance requirements in corrosion protection, cost, operability, and health and safety, while typically specifying that performance must be equal to or greater than existing systems. The overall objective of the collaborative effort between NASA TEERM and ESA is to test and evaluate coating systems (pretreatments, pretreatments with primer, and pretreatments with primer and topcoat) as replacements for hexavalent chrome coatings in aerospace applications. This objective will be accomplished by testing promising coatings identified from previous NASA, ESA, Department of Defense (DOD), and other project experience. Additionally, several new materials will be analyzed according to ESA-identified specifications.

  10. The effect of inhaled chromium on different exhaled breath condensate biomarkers among chrome-plating workers.

    PubMed

    Caglieri, Andrea; Goldoni, Matteo; Acampa, Olga; Andreoli, Roberta; Vettori, Maria Vittoria; Corradi, Massimo; Apostoli, Pietro; Mutti, Antonio

    2006-04-01

    Chromium is corrosive, cytotoxic, and carcinogenic for humans and can induce acute and chronic lung tissue toxicity. The aim of this study was to investigate Cr levels in exhaled breath condensate (EBC) of workers exposed to Cr(VI) and to assess their relationship with biochemical changes in the airways by analyzing EBC biomarkers of oxidative stress, namely, hydrogen peroxide (H2O2) and malondialdehyde (MDA). EBC samples were collected from 24 chrome-plating workers employed in a chrome-plating plant both before and after the Friday work shift and before the work shift on the following Monday. Cr-EBC levels increased from the beginning (5.3 microg/L) to the end of Friday (6.4 microg/L) but were considerably lower on Monday morning (2.8 microg/L). A similar trend was observed for H2O2-EBC levels (which increased from 0.36 microM to 0.59 microM on Friday and were 0.19 microM on Monday morning) and MDA-EBC levels (which increased from 8.2 nM to 9.7 nM on Friday and were 6.6 nM on Monday). Cr-EBC levels correlated with those of H2O2-EBC (r = 0.54, p < 0.01) and MDA-EBC (r = 0.59, p < 0.01), as well as with urinary Cr levels (r = 0.25, p < 0.05). The results of this study demonstrate that EBC is a suitable matrix that can be used to investigate both Cr levels and biomarkers of free radical production sampling the epithelial-lining fluid of workers exposed to Cr(VI).

  11. Determination of hexavalent chromium in exhaled breath condensate and environmental air among chrome plating workers

    PubMed Central

    Goldoni, Matteo; Caglieri, Andrea; Poli, Diana; Vettori, Maria Vittoria; Corradi, Massimo; Apostoli, Pietro; Mutti, Antonio

    2006-01-01

    Chromium speciation has attracted attention because of the different toxicity of Cr(III), which is considered relatively non-toxic, and Cr(VI), which can cross cell membranes mainly as a chromate anion and has been classified as a class I human carcinogen. The aims of the present study were to measure soluble Cr(VI) levels in environmental samples, to develop a simple method of quantifying Cr(VI) in exhaled breath condensate (EBC), and to follow the kinetics of EBC Cr(VI) in chrome plating workers. Personal air samples were collected from 10 chrome platers; EBC was collected from the same workers immediately after the work shift on Tuesday and before the work shift on the following Wednesday. Environmental and EBC Cr(VI) levels were determined by means of colorimetry and electrothermal absorption atomic spectrometry, respectively. The method of detecting Cr(VI) in environmental air was based on the extraction of the Cr(VI)-diphenylcarbazide (Cr(VI)–DPC) complex in 1-butanol, whereas EBC Cr(VI) was determined using a solvent extraction of Cr(VI) as an ion pair with tetrabutylammonium ion, and subsequent direct determination of the complex (Cr(VI)–DPC) in EBC. Kinetic data showed that airborne Cr(VI) was reduced by 50% in airway lining fluid sampled at the end of exposure and that there was a further 50% reduction after about 15 h. The persistence of Cr(VI) in EBC supports the use of EBC in assessing target tissue levels of Cr(VI). PMID:17047732

  12. Black holes, compact objects and solar system tests in non-relativistic general covariant theory of gravity

    SciTech Connect

    Greenwald, Jared; Satheeshkumar, V.H.; Wang, Anzhong E-mail: VHSatheeshkumar@baylor.edu

    2010-12-01

    We study spherically symmetric static spacetimes generally filled with an anisotropic fluid in the nonrelativistic general covariant theory of gravity. In particular, we find that the vacuum solutions are not unique, and can be expressed in terms of the U(1) gauge field A. When solar system tests are considered, severe constraints on A are obtained, which seemingly pick up the Schwarzschild solution uniquely. In contrast to other versions of the Horava-Lifshitz theory, non-singular static stars made of a perfect fluid without heat flow can be constructed, due to the coupling of the fluid with the gauge field. These include the solutions with a constant pressure. We also study the general junction conditions across the surface of a star. In general, the conditions allow the existence of a thin matter shell on the surface. When applying these conditions to the perfect fluid solutions with the vacuum ones as describing their external spacetimes, we find explicitly the matching conditions in terms of the parameters appearing in the solutions. Such matching is possible even without the presence of a thin matter shell.

  13. Acceleration of black hole universe

    NASA Astrophysics Data System (ADS)

    Zhang, T. X.; Frederick, C.

    2014-01-01

    Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

  14. Green chemistry approaches to leather tanning process for making chrome-free leather by unnatural amino acids.

    PubMed

    Krishnamoorthy, G; Sadulla, S; Sehgal, P K; Mandal, Asit Baran

    2012-05-15

    In the present study, green and sustainable method or eco-friendly approaches to tanning process based on unnatural D-amino acids (D-AA)-aldehyde (Ald) as a substitute for chrome-free tanning has been attempted. The distribution of optically active D-AA in tanned leather, the hydrothermal stability, the mechanical properties and resistance to collagenolytic activity of tanned leather, the evaluation of eco-friendly characteristics were investigated. Scanning electron microscopic (SEM) and Atomic force microscopic (AFM) analyses indicate the surface morphology and roughness, respectively, of the tanned leather collagen matrix. Shrinkage and Differential scanning calorimetric (DSC) analyses shows that the shrinkage temperature (T(s)) and denaturation temperature (T(d)) of tanned leather are related to the content of D-AA+Ald present in the leather matrix. It has been found that the T(s) of D-AA tanned leather is more than that of Ald tanned leather and also more or less equal to chrome tanned leather. Environmental impact assessment (EIA) shows that the developed process results in significant reduction in total solids content (TSC) and improves better biodegradability of organic compound present in the effluent compared to chrome tanning. PMID:22421341

  15. Green chemistry approaches to leather tanning process for making chrome-free leather by unnatural amino acids.

    PubMed

    Krishnamoorthy, G; Sadulla, S; Sehgal, P K; Mandal, Asit Baran

    2012-05-15

    In the present study, green and sustainable method or eco-friendly approaches to tanning process based on unnatural D-amino acids (D-AA)-aldehyde (Ald) as a substitute for chrome-free tanning has been attempted. The distribution of optically active D-AA in tanned leather, the hydrothermal stability, the mechanical properties and resistance to collagenolytic activity of tanned leather, the evaluation of eco-friendly characteristics were investigated. Scanning electron microscopic (SEM) and Atomic force microscopic (AFM) analyses indicate the surface morphology and roughness, respectively, of the tanned leather collagen matrix. Shrinkage and Differential scanning calorimetric (DSC) analyses shows that the shrinkage temperature (T(s)) and denaturation temperature (T(d)) of tanned leather are related to the content of D-AA+Ald present in the leather matrix. It has been found that the T(s) of D-AA tanned leather is more than that of Ald tanned leather and also more or less equal to chrome tanned leather. Environmental impact assessment (EIA) shows that the developed process results in significant reduction in total solids content (TSC) and improves better biodegradability of organic compound present in the effluent compared to chrome tanning.

  16. In-Situ Fabrication of a Self-Aligned Selective Emitter Silicon Solar Cell Using the Gold Top Contacts To Facilitate the Synthesis of a Nanostructured Black Silicon Antireflective Layer Instead of an External Metal Nanoparticle Catalyst.

    PubMed

    Lu, Yen-Tien; Barron, Andrew R

    2015-06-10

    Silicon solar cells with nanopore-type black silicon (b-Si) antireflection (AR) layers and self-aligned selective emitter (SE) are reported in which the b-Si structure is prepared without the traditional addition of a nanoparticle (NP) catalyst. The contact-assisted chemical etching (CACE) method is reported here for the first time, in which the metal top contacts on silicon solar cell surfaces function as the catalysts for b-Si fabrication and the whole etching process can be done in minutes at room temperature. The CACE method is based on the metal-assisted chemical etching (MACE) solution but without or metal precursor in the Si etchant (HF:H2O2:H2O), and the Au top contacts, or catalysts, are not removed from the solar cell surface after the etching. The effects of etching time, HF and H2O2 concentration, and the HF:H2O2 ratio on the b-Si morphology, surface reflectivity, and solar cell efficiency have been investigated. Higher [HF] and [H2O2] with longer etching time cause collapse of the b-Si nanoporous structure and penetration of the p-n junctions, which are detrimental to the solar cell efficiency. The b-Si solar cell fabricated with the HF:H2O2:H2O volume ratio of 3:3:20 and a 3 min etch time shows the highest efficiency 8.99% along with a decrease of reflectivity from 36.1% to 12.6% compared to that of the nonetched Si solar cell.

  17. Black Consciousness

    ERIC Educational Resources Information Center

    Hraba, Joseph; Siegman, Jack

    1974-01-01

    Black militancy is treated as an instance of class consciousness with criteria and scales developed to measure black consciousness and "self-placement" into black consciousness. These dimensions are then investigated with respect to the social and symbolic participation in the ideology of the black movement on the part of a sample of black…

  18. Black holes

    PubMed Central

    Brügmann, B.; Ghez, A. M.; Greiner, J.

    2001-01-01

    Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries. PMID:11553801

  19. Mid-term survivorship and clinical outcomes of cobalt-chrome and oxidized zirconium on highly crosslinked polyethylene

    PubMed Central

    Petis, Stephen M.; Vasarhelyi, Edward M.; Lanting, Brent A.; Howard, James L.; Naudie, Douglas D.R.; Somerville, Lyndsay E.; McCalden, Richard W.

    2016-01-01

    Background The choice of bearing articulation for total hip arthroplasty in younger patients is amenable to debate. We compared mid-term patient-reported outcomes and survivorship across 2 different bearing articulations in a young patient cohort. Methods We reviewed patients with cobalt-chrome or oxidized zirconium on highly crosslinked polyethylene who were followed prospectively between 2004 and 2012. Kaplan–Meier analysis was used to determine predicted cumulative survivorship at 5 years with all-cause and aseptic revisions as the outcome. We compared patient-reported outcomes, including the Harris hip score (HHS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Short-form 12 (SF-12) scores. Results A total of 622 patients were followed during the study period. Mean follow-up was 8.2 (range 2.0–10.6) years for cobalt-chrome and 7.8 (range 2.1–10.7) years for oxidized zirconium. Mean age was 54.9 ± 10.6 years for cobalt-chrome and 54.8 ± 10.7 years for oxidized zirconium. Implant survivorship was 96.0% (95% confidence interval [CI] 94.9%–97.1%) for cobalt-chrome and 98.7% (95% CI 98.0%–99.4%) for oxidized zirconium on highly crosslinked polyethylene for all-cause revisions, and 97.2% (95% CI 96.2%–98.2%) for cobalt-chrome and 99.0% (95% CI 98.4%–99.6%) for oxidized zirconium for aseptic revisions. An age-, sex- and diagnosis-matched comparison of the HHS, WOMAC and SF-12 scores demonstrated no significant changes in clinical outcomes across the groups. Conclusion Both bearing surface couples demonstrated excellent mid-term survivorship and outcomes in young patient cohorts. Future analyses on wear and costs are warranted to elicit differences between the groups at long-term follow-up. PMID:26812409

  20. Formation of Cr(III) hydroxides from chrome alum solutions. 1: Precipitation of active chromium hydroxide

    SciTech Connect

    Avena, M.J.; Giacomelli, C.E.; De Pauli, C.P.

    1996-06-25

    The hydrolysis of Cr(III) and precipitation of colloidal chromium hydroxides are important processes occurring in soils and natural waters. The formation of active chromium hydroxide, Cr(OH){sub 3}{center_dot}3H{sub 2}O, was studied through potentiometric titrations and turbidimetric measurements. UV-Vis and IR spectroscopies were also employed to characterize the synthesized solid. The rapid addition of NaOH solution to aqueous chrome alum (KCr(SO{sub 4}){sub 2}{center_dot}12H{sub 2}O) solutions caused the immediate precipitation of the active material. Only monomeric Cr(III) species seemed to be participating in the precipitation process; neither chromium polymers nor complexes with anions (SO{sub 4}{sup 2{minus}}, Cl{sup {minus}}, NO{sub 3}{sup {minus}}, ClO{sub 4}{sup {minus}}) influenced the fast formation of Cr(OH){sub 3}{center_dot}3H{sub 2}O. Titration studies allowed the determination of several hydrolysis and precipitation constants for Cr(III). Nevertheless, they cannot be used for the estimate of Cr(OH){sub 3}{sup 0} formation constant.

  1. Safe disposal of toxic chrome buffing dust generated from leather industries.

    PubMed

    Swarnalatha, S; Srinivasulu, T; Srimurali, M; Sekaran, G

    2008-01-31

    The high concentration of trivalent chromium along with organic/inorganic compounds in chrome buffing dust (CBD), the solid waste discharged from leather industries, causes severe groundwater contamination on land co-disposal and chronic air pollution during thermal incineration. In the present investigation, CBD was subjected to starved air incineration (SAI) at 800 degrees C in a thermal incinerator under different flow rates of oxygen to optimize the oxygen required to incinerate the organic compounds and simultaneously preventing the conversion of Cr(3+) to Cr(6+). The energy audit of SAI of buffing dust under the external supply of oxygen was carried out under different incineration conditions. The bottom ash from SAI was effectively solidified/stabilized using Portland cement and fine aggregate. The solidified blocks were tested for unconfined compressive strength and heavy metal leaching. Unconfined compressive strength of the blocks was in the range of 120-180 kg/cm(2). The stabilization of chromium(III) in the cement gel matrix was confirmed using Scanning Electron Microscopy SEM, Electron Paramagnetic Resonance spectroscopy (EPR) and X-ray diffraction spectroscopy (XRD). Leachability studies through TCLP on solidified blocks were carried out to determine the degree of leaching of chromium and organic compounds (expressed as COD) under standard conditions.

  2. Leaching behavior of chromium in chrome shaving generated in tanning process and its stabilization.

    PubMed

    Erdem, Mehmet; Ozverdi, Arzu

    2008-08-15

    In this study, leaching properties and pollution potential of chromium in chrome shaving (CS), which is a solid residue of leather industry, containing 2.27% Cr were investigated and thermal stabilization procedure was applied to the CS for chromium immobilization. For this purpose, firstly, effects of the liquid/solid ratio, contact time, pH and sequential extraction on the leaching behavior of chromium in the CS were studied. It was determined that the CS-caused chromium pollution is a hazardous material for environment. Thermal stabilization procedure was applied to the CS in the temperature range of 250-500 degrees C for the chromium immobilization. Effective stabilization of chromium in the CS was achieved by heating of CS at 350 degrees C under CO(2) atmosphere. Leaching experiments were also carried out with the samples obtained from the stabilization process and the results compared with that of the CS. Also, TCLP test method was applied to the samples to determine pollution potentials and discharge situations of the CS and its stabilization products. While the chromium concentrations in the test solutions of all samples stabilized thermally at above 350 degrees C were below the USEPA regulatory limit of 5 mg/l, the concentration of chromium leached out from the CS was 30-fold bigger than the USEPA regulatory limit.

  3. Review of black surfaces for space-borne infrared systems

    NASA Astrophysics Data System (ADS)

    Persky, M. J.

    1999-05-01

    Low reflectivity (``black'') surface treatments for space-borne infrared systems are reviewed. The uses of black surfaces in general, as well as for specific space-borne applications are discussed. Compositions of a wide variety of surface treatments with examples of experimental data to characterize performances are provided. Specific treatments included are: Ames 24E paint; AZKO 463 (Sikkens, Cat-A-Lac) paint; Ball IR black paint; Chemglaze (Aeroglaze) Z306 and Z302 paints; Eccosorb 268E paint; Parsons Black paint; black anodize; black Hardlub; black Hardcoat; Martin Black; InfraBlack; Enhanced Martin Black; Ebonal C; Teflon; ion beam textured; appliqués black chrome; black etched beryllium on beryllium; plasma sprayed boron on beryllium; plasma sprayed beryllium on beryllium; boron carbide on POCO graphite; and Kapton. Data presented for some but not all of the surfaces include: spectrally integrated, 5-25 μm hemispherical-directional reflectance; spectral reflectance at wavelengths between 2 and 500 μm for a variety of incident angles from 5° to 80° and bidirectional reflectance at a number of wavelengths between 5 and 300 μm for a variety of incident angles from 0° to 80°. The instrumentation employed to obtain these data is briefly described. Long term stability of optical performance, as well as manufacturing reproducibility is demonstrated for several of the surfaces. Outgassing and atomic oxygen interaction information is also included. Methodology for calorimetric measurement of hemispherical emittance as an alternative to optical measurements is given.

  4. Macrophages detoxify the genotoxic and cytotoxic effects of surgical cobalt chrome alloy particles but not quartz particles on human cells in vitro.

    PubMed

    Papageorgiou, I; Shadrick, V; Davis, S; Hails, L; Schins, R; Newson, R; Fisher, J; Ingham, E; Case, C P

    2008-08-25

    Particles of surgical cobalt chrome alloy are cytotoxic and genotoxic to human fibroblasts in vitro. In vivo orthopaedic patients are exposed to cobalt chrome particles as a result of wear of a joint replacement. Many of the wear debris particles that are produced are phagocytosed by macrophages that accumulate at the site of the worn implant and are disseminated to local and distant lymph nodes the liver and the spleen. In this study we have tested whether this process of phagocytosis could have altered the cytotoxic and genotoxic properties of the cobalt chrome particles. Quartz particles have been investigated as a control. Micron-sized particles of cobalt chrome alloy were internalised by either white cells of peripheral blood or by THP-1 monocytes for 1 week and 1 day, respectively. The particles were then extracted and presented at different doses to fibroblasts for 1 day. There was a reduction of the cytotoxicity and genotoxicity of the cobalt chrome particles after phagocytosis by white cells or THP-1 cells. Cobalt chrome particles that were internalised by fibroblasts also showed a reduction of their cytotoxicity but not their genotoxicity. In contrast the cytotoxicity and genotoxicity of quartz particles was increased after internalisation by THP-1 cells. The surface morphology of the cobalt chrome particles but not the quartz particles was changed after phagocytosis by THP-1 cells. This study suggests that the genotoxic and cytotoxic properties of particles that fall within the size range for phagocytosis may be highly complex in vivo and depend on the combination of material type and previous phagocytosis. These results may have relevance for particle exposure from orthopaedic implants and from environmental or industrial pollution.

  5. Low-mass black holes as the remnants of primordial black hole formation.

    PubMed

    Greene, Jenny E

    2012-01-01

    Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

  6. Low-mass black holes as the remnants of primordial black hole formation.

    PubMed

    Greene, Jenny E

    2012-01-01

    Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism. PMID:23250434

  7. Quantitative mineralogical characterization of chrome ore beneficiation plant tailing and its beneficiated products

    NASA Astrophysics Data System (ADS)

    Das, S. K.

    2015-04-01

    Mineralogical characterization and liberation of valuable minerals are primary concerns in mineral processing industries. The present investigation focuses on quantitative mineralogy, elemental deportment, and locking-liberation characteristics of the beneficiation of tailings from a chrome ore beneficiation plant in the Sukinda region, Odisha; methods used for the study of the beneficiated tailings are QEMSCAN®, X-ray diffraction (XRD), and mineral chemistry by a scanning electron microscope equipped with an energy-dispersive spectrometer (SEM-EDS). The tailing sample was fine grained (69.48wt% below 45 μm size), containing 20.25wt% Cr2O3 and 39.19wt% Fe2O3, with a Cr:Fe mass ratio of 0.51. Mineralogical investigations using QEMSCAN studies revealed that chromite, goethite, and gibbsite are the dominant mineral phases with minor amounts of hematite, kaolinite, and quartz. The sample contained 34.22wt% chromite, and chromite liberation is more than 80% for grains smaller than 250 μm in size. Based on these results, it was predicted that liberated chromite and high-grade middling chromite particles could be separated from the gangue by various concentration techniques. The tailing sample was beneficiated by hydrocyclone, tabling, wet high-intensity magnetic separation (WHIMS), and flotation in order to recover the chromite. A chromite concentrate with 45.29wt% Cr2O3 and a Cr:Fe mass ratio of 1.85 can be produced from these low-grade chromite ore beneficiation plant rejects.

  8. Influence of particle size and reactive oxygen species on cobalt chrome nanoparticle-mediated genotoxicity.

    PubMed

    Raghunathan, Vijay Krishna; Devey, Michael; Hawkins, Sue; Hails, Lauren; Davis, Sean A; Mann, Stephen; Chang, Isaac T; Ingham, Eileen; Malhas, Ashraf; Vaux, David J; Lane, Jon D; Case, Charles P

    2013-05-01

    Patients with cobalt chrome (CoCr) metal-on-metal (MOM) implants may be exposed to a wide size range of metallic nanoparticles as a result of wear. In this study we have characterised the biological responses of human fibroblasts to two types of synthetically derived CoCr particles [(a) from a tribometer (30 nm) and (b) thermal plasma technology (20, 35, and 80 nm)] in vitro, testing their dependence on nanoparticle size or the generation of oxygen free radicals, or both. Metal ions were released from the surface of nanoparticles, particularly from larger (80 nm) particles generated by thermal plasma technology. Exposure of fibroblasts to these nanoparticles triggered rapid (2 h) generation of reactive oxygen species (ROS) that could be eliminated by inhibition of NADPH oxidase, suggesting that it was mediated by phagocytosis of the particles. The exposure also caused a more prolonged, MitoQ sensitive production of ROS (24 h), suggesting involvement of mitochondria. Consequently, we recorded elevated levels of aneuploidy, chromosome clumping, fragmentation of mitochondria and damage to the cytoskeleton particularly to the microtubule network. Exposure to the nanoparticles resulted in misshapen nuclei, disruption of mature lamin B1 and increased nucleoplasmic bridges, which could be prevented by MitoQ. In addition, increased numbers of micronuclei were observed and these were only partly prevented by MitoQ, and the incidence of micronuclei and ion release from the nanoparticles were positively correlated with nanoparticle size, although the cytogenetic changes, modifications in nuclear shape and the amount of ROS were not. These results suggest that cells exhibit diverse mitochondrial ROS-dependent and independent responses to CoCr particles, and that nanoparticle size and the amount of metal ion released are influential.

  9. Development of environmentally friendly non-chrome conversion coatings for cold-rolled steel

    NASA Astrophysics Data System (ADS)

    Zhang, Jinming

    Steel producers use various organic and inorganic coatings to protect cold-rolled steel (CRS) sheets from corrosion during shipment and storage. It is well known that CRS sheets can be protected from corrosion by galvanizing, phosphating, chromating, topcoating with organic, or their combinations. The chromate rinsing is particularly effective for preventing white rusting of galvanized steel. But there is an increasing interest in a replacement for the chromating process because of environmental and health concerns. The objective of the present work is to develop a chrome-free conversion coating for steel sheets. Various carboxylic acids and their salts have been studied for coating phosphated electrogalvanized (EG) steel sheets, including 10-undecenoic acid (UA), oleic acid (OA), and other fatty acids such as stearic acid (SA) and palmitic acid (PA). When they were used alone, or subsequently coated with resin, they could produce a highly hydrophobic surface and improve the corrosion resistance. Thiols such as 1-octadecanethiol (ODT) can form a self-assembled monolayer on metal substrates. This close-packed monolayer could provide an excellent corrosion resistance for EG steel sheets. It was capable of withstanding 50˜60 hours of salt spray test (SST) although its thickness was only a few nanometers. The EG steel itself usually started rusting only after 2˜4 hours of salt spray. In another coating system, thiols were mixed with a conventional resin to improve the corrosion resistance of EG steel. This new technique gave 100˜120 hours of corrosion resistance. When the resin was applied directly on EG steel surface, its corrosion resistance was less than 72 hours. It was shown that further optimization of this technique increased the corrosion resistance to 200 hours and more in the standard SST.

  10. Black Appalachians.

    ERIC Educational Resources Information Center

    Waage, Fred, Ed.; Cabbell, Ed, Ed.

    1986-01-01

    This issue of "Now and Then" focuses on black Appalachians, their culture, and their history. It contains local histories, articles, and poems and short stories by Appalachian blacks. Articles include: "A Mountain Artist's Landscape," a profile of artist Rita Bradley by Pat Arnow; "A Part and Apart," a profile of black historian Ed Cabbell by Pat…

  11. Talking Black.

    ERIC Educational Resources Information Center

    Abrahams, Roger D.

    This book contains essays which focus on the systems of communication that operate within and between various social segments of Afro-American communities in the United States. The essays are presented under the following headings: (1) "Getting Into It: Black Talk, Black Life and the Academic," (2) "'Talking My Talk': Black Talk Varieties and…

  12. Black Students.

    ERIC Educational Resources Information Center

    Edwards, Harry

    The black student revolt did not start with the highly publicized activities of the black students at San Francisco State College. The roots of the revolt lie deeply imbedded within the history and structure of the overall black liberation struggle in America. The beginnings of this revolt can be found in the students of Southern Negro colleges in…

  13. Black Psychology.

    ERIC Educational Resources Information Center

    Jones, Reginald L., Ed.

    The contents of the present volume, designed to bring together in a single place writings by the new black psychologists and other black social and behavioral scientists, are organized in seven parts, as follows: Part I, "Black Psychology: Perspectives," includes articles by Cedric Clark, Wade W. Nobles, Doris P. Mosby, Joseph White, and William…

  14. Poultry feed based on protein hydrolysate derived from chrome-tanned leather solid waste: creating value from waste.

    PubMed

    Chaudhary, Rubina; Pati, Anupama

    2016-04-01

    Leather industry generates huge amount of chrome-containing leather solid waste which creates major environment problems to tanners worldwide. Chrome-tanned leather solid waste is primarily chromium complex of collagen protein. The presence of chromium limits its protein application in animal feed industry. The purified protein hydrolysate with zero chromium could be used in poultry feed. In this study, an attempt has been made to assess performance of poultry with purified protein hydrolysate as a feed derived from chrome-tanned leather waste as partial replacement of soyabean meal as a sole source of protein for growing broiler chickens. Growth study was conducted to evaluate the effect of feeding protein hydrolysate on performance and physiochemical characteristics of meat of broiler chickens. Two experimental diets containing various levels of protein hydrolysate (EI-20 % and EII-30 %) were evaluated. The comparative study was performed as control with soyabean meal. Daily feed intake, body weight gain and feed conversion ratio were measured from day 8 to day 35. At the end of the study, birds were randomly selected and slaughtered to evaluate for physiochemical characteristics of meat. Diet had significant effects on feed intake and body weight gain. Birds fed with 20 and 30 % protein hydrolysate consumed 9.5 and 17.5 % higher amount of feed and gained 6.5 and 16.6 % higher than soyabean meal-fed birds. The current study produced evidence that protein hydrolysate can replace up to 75 % of soyabean meal in broiler diets without affecting either growth performance or meat characteristics.

  15. Detrital chrome spinel evidence for a Neotethyan intra-oceanic island arc collision with India in the Paleocene

    NASA Astrophysics Data System (ADS)

    Baxter, Alan T.; Aitchison, Jonathan C.; Ali, Jason R.; Chan, Jacky Sik-Lap; Chan, Gavin Heung Ngai

    2016-10-01

    Models that support a single collision scenario for India and Eurasia are incompatible with the evidence that an intra-oceanic island arc (IOIA) existed within the Neotethyan Ocean. Understanding the spatial and temporal extent of any IOIA is crucial for India-Eurasia collision studies as the entire ocean, including any intra-oceanic features, must have been consumed or emplaced prior to continental collision. Here, we review what is known about the Neotethyan IOIA and report evidence from sedimentary successions in NW India and southern Tibet to constrain when and where it was emplaced. We use detrital mineral geochemistry and supporting provenance and age data to identify the source of the sediments and compare the timing of erosion of IOIA-derived material in both regions. Detrital chrome spinels, extracted from distinct sedimentary horizons in southern Tibet (Sangdanlin) and NW India (Ladakh), exhibit similar average geochemical values (TiO2 = 0.09 and 0.24%, Cr# = 0.66 and 0.68 and Mg# = 0.45 and 0.53, respectively) and supra-subduction zone (SSZ), forearc peridotite signatures. Furthermore, they overlap with in-situ chrome spinels reported from the Spongtang Ophiolite in NW India and the Sangsang Ophiolite in southern Tibet. As with many of the ophiolitic remnants that crop out in and adjacent to the Yarlung-Tsangpo and Indus suture zones (YTSZ and ISZ respectively), the Spongtang and Sangsang ophiolites formed in an IOIA setting. Linking the source of the detrital chrome spinels to those analysed from remnant IOIA massifs in the YTSZ and ISZ is strong evidence for the emplacement of the IOIA onto the Indian margin. The timing of the IOIA collision with India is constrained by the depositional ages of the chrome spinel-bearing sediments to the end of the Paleocene (Thanetian) in southern Tibet and the Early Eocene in NW India. This indirectly provides a maximum age constraint of Late Paleocene-Early Eocene for intercontinental collision between India and

  16. Evidence for Degradation of the Chrome Yellows in Van Gogh's Sunflowers: A Study Using Noninvasive In Situ Methods and Synchrotron-Radiation-Based X-ray Techniques.

    PubMed

    Monico, Letizia; Janssens, Koen; Hendriks, Ella; Vanmeert, Frederik; Van der Snickt, Geert; Cotte, Marine; Falkenberg, Gerald; Brunetti, Brunetto Giovanni; Miliani, Costanza

    2015-11-16

    This paper presents firm evidence for the chemical alteration of chrome yellow pigments in Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam). Noninvasive in situ spectroscopic analysis at several spots on the painting, combined with synchrotron-radiation-based X-ray investigations of two microsamples, revealed the presence of different types of chrome yellow used by Van Gogh, including the lightfast PbCrO4 and the sulfur-rich PbCr1-x Sx O4 (x≈0.5) variety that is known for its high propensity to undergo photoinduced reduction. The products of this degradation process, i.e., Cr(III) compounds, were found at the interface between the paint and the varnish. Selected locations of the painting with the highest risk of color modification by chemical deterioration of chrome yellow are identified, thus calling for careful monitoring in the future. PMID:26482035

  17. Evidence for Degradation of the Chrome Yellows in Van Gogh's Sunflowers: A Study Using Noninvasive In Situ Methods and Synchrotron-Radiation-Based X-ray Techniques.

    PubMed

    Monico, Letizia; Janssens, Koen; Hendriks, Ella; Vanmeert, Frederik; Van der Snickt, Geert; Cotte, Marine; Falkenberg, Gerald; Brunetti, Brunetto Giovanni; Miliani, Costanza

    2015-11-16

    This paper presents firm evidence for the chemical alteration of chrome yellow pigments in Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam). Noninvasive in situ spectroscopic analysis at several spots on the painting, combined with synchrotron-radiation-based X-ray investigations of two microsamples, revealed the presence of different types of chrome yellow used by Van Gogh, including the lightfast PbCrO4 and the sulfur-rich PbCr1-x Sx O4 (x≈0.5) variety that is known for its high propensity to undergo photoinduced reduction. The products of this degradation process, i.e., Cr(III) compounds, were found at the interface between the paint and the varnish. Selected locations of the painting with the highest risk of color modification by chemical deterioration of chrome yellow are identified, thus calling for careful monitoring in the future.

  18. Final Test Report: Hexavalent Chrome Free Coatings for Electronics Electromagnetic Interference (EMI) Shielding Effectiveness (SE)

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2016-01-01

    The test results for Salt Spray Resistance, Static Heat and Humidity and Marine Environment can be found in Sections 3.1.3.3, 3.1.4.3 and 3.1.5.3 respectively. In summary, both the Metalast TCP and SurTec 650 Type 2 conversion coatings perform very similar to the incumbent Type 1 conversion coating against both 6061 and 5052 aluminum under all three test conditions. Significant prior work was performed to select the aluminum and conversion coating included within this test cycle; Reference - NASA GSDO Program Hexavalent Chrome Alternatives Final Pretreatments Test Report Task Order: NNH12AA45D September 01, 2013. As illustrated in the data, the 6061 aluminum panels SLIGHTLY out-performed the 5052 aluminum panels. Individual shielding effectiveness graphs for each panel are included within Appendix C and D. One other notable effect found during review of the data is that the Test Panels exposed to B117 Salt Fog reduced in shielding effectiveness significantly more than the Marine Environment Test Panels. The shielding effectiveness of the Marine Test Panels was approximately 20dB higher than the Test Panels that underwent B117 Salt Fog Exposure. The intent of this evaluation was not to maximize shielding effectiveness values. The same Parker Chomerics Cho-Seal 6503 gasket material was used for all panels with aluminum and conversion coating variants. A typical EMI gasket design for corrosive environments would be done quite differently. The intent was to execute a test that would provide the best possible evaluation of different aluminum materials and conversion coatings in corrosive environments. The test program achieved this intent. The fact that the two aluminums and two Type II conversion coatings performed similar to the incumbent Type 1 conversion coating is a positive outcome. It was desired to have an outcome that further differentiation the performance of two aluminum types and two conversion coating types but this could not be extracted by the test

  19. The fatigue life of contoured cobalt chrome posterior spinal fusion rods.

    PubMed

    Nguyen, T-Q; Buckley, J M; Ames, C; Deviren, V

    2011-02-01

    Intraoperative contouring of posterior rods in lumbar arthrodesis constructs introduces stress concentrations that can substantially reduce fatigue life. The sensitivity of titanium (Ti) and stainless steel (SS) to intraoperative contouring has been established in the literature; however, notch sensitivity has yet to be quantified for cobalt chrome (CoCr), which is now being advocated for use in posterior arthrodesis constructs. The goal of this study is to evaluate the sensitivity of CoCr rods to intraoperative contouring for posterior lumbar screwrod arthrodesis constructs. In this paper lumbar bilateral vertebrectomy models are constructed based on ASTM F1717-01 with curved rods (26-30 degrees total curvature) and poly-axial pedicle screws. Three types of constructs are assembled: first, 5.5 mm SS rods with SS screws (6.5 x 35 mm), second, 6.0 mm Ti rods with Ti screws (7.5 x 35 mm), and third, 6.0 mm CoCr rods with Ti screws (7.5 x 35 mm). All specimens are tested at 4 Hz in dynamic axial compression-bending with a load ratio of ten and maximum load levels of 250, 400, and 700 N until run-out at 2 000 000 cycles. Results are presented that show that the fatigue life of CoCr constructs tend to be greater than Ti constructs at all levels. At the 400 N maximum loading, CoCr lasts an average of 350 000 cycles longer than the Ti constructs. The CoCr constructs are able to sustain the 250 N load until run-out at 2 000 000 cycles but they fail at high load levels (maximum 700 N). The CoCr constructs fail at the neck of the Ti screw at high loads whereas Ti screws fail at the notch induced by contouring. Since CoCr is compatible with magnetic resonance imaging and has high static strength characteristics, the results of this study suggest that it may be an appropriate substitute for Ti. PMID:21428153

  20. Effects of surface roughness and chrome plating of punch tips on the sticking tendencies of model ibuprofen formulations.

    PubMed

    Roberts, Matthew; Ford, James L; MacLeod, Graeme S; Fell, John T; Smith, George W; Rowe, Philip H

    2003-09-01

    The sticking of three model ibuprofen-lactose formulations with respect to compaction force and the surface quality of the upper punch were assessed. Compaction was performed at 10, 25 or 40 kN using an instrumented single-punch tablet press. Two sets of 12.5-mm flat-faced punches were used to evaluate the influence of surface quality. A third set of chrome-plated tooling was also used. Surface profiles (Taylor Hobson Talysurf 120) of the normal tooling upper punches indicated a large difference in quality. The punches were subsequently classified as old (Ra = 0.33 microm) or new (Ra = 0.04 microm) where Ra is the mean of all positive deviations from zero. Surface profiles of sample tablets were also obtained. Following compaction, ibuprofen attached to the face was quantified by spectroscopy. Punch surface roughness, compaction force and the blend composition were all significant factors contributing to sticking. Chrome plating of punch faces increased sticking at a low compaction force but decreased sticking at higher forces. Surface roughness of the tablets did not correlate with the corresponding data for sticking, indicating that this is not a suitable method of quantifying sticking.

  1. Black holes in the Milky Way Galaxy

    PubMed Central

    Filippenko, Alexei V.

    1999-01-01

    Extremely strong observational evidence has recently been found for the presence of black holes orbiting a few relatively normal stars in our Milky Way Galaxy and also at the centers of some galaxies. The former generally have masses of 4–16 times the mass of the sun, whereas the latter are “supermassive black holes” with millions to billions of solar masses. The evidence for a supermassive black hole in the center of our galaxy is especially strong. PMID:10468548

  2. Black holes in the milky way galaxy.

    PubMed

    Filippenko, A V

    1999-08-31

    Extremely strong observational evidence has recently been found for the presence of black holes orbiting a few relatively normal stars in our Milky Way Galaxy and also at the centers of some galaxies. The former generally have masses of 4-16 times the mass of the sun, whereas the latter are "supermassive black holes" with millions to billions of solar masses. The evidence for a supermassive black hole in the center of our galaxy is especially strong.

  3. Environmental Durability of Electroplated Black Chromium

    NASA Technical Reports Server (NTRS)

    Lowery, J. R.

    1983-01-01

    Report describes tests of durability of electroplated black chromium coatings on solar-collector panels in rural, industrial, and seacoast environments for 60, 36, and 13 months, respectively. Black-chromium coating showed exceptionally-good optical durability in all three environments.

  4. Green microwave switching from oxygen rich yellow anatase to oxygen vacancy rich black anatase TiO₂ solar photocatalyst using Mn(II) as 'anatase phase purifier'.

    PubMed

    Ullattil, Sanjay Gopal; Periyat, Pradeepan

    2015-12-01

    Green and rapid microwave syntheses of 'yellow oxygen rich' (YAT-150) and 'black oxygen vacancy rich' (BAT-150) anatase TiO2 nanoparticles are reported for the first time. YAT-150 was synthesized using only titanium(iv) butoxide and water as precursors. The in situ precursor modification by Mn(ii) acetate switched anatase TiO2 from YAT-150 to BAT-150. The entry of Mn(2+) into the crystal lattice of anatase TiO2 paved the way for peak texturing in the existing peak orientations along with the origin of three new anatase TiO2 peaks in the (103), (213) and (105) directions. The as synthesized ultra-small (∼5 nm) yellow and black anatase TiO2 nanoparticles were found to be two fold and four fold more photoactive than the commercially available photocatalyst Degussa-P25 under sunlight illumination. PMID:26523536

  5. The First Black Holes

    NASA Astrophysics Data System (ADS)

    Abel, T.

    star. Within this wide range of possible initial masses the death of these star will lead very different remnants (Heger and Woosley 2001). In the case of stars with masses larger than 260 solar mass no metals may be released in black holes are the natural outcome. This may be an interesting possibility to form intermediate mass black holes which are attractive seeds to be nurtured to the super-massive black holes observed in the centers of nearby galaxies. However, no metals would be released and it would prove difficult to understand the transition to the formation of low mass metal enriched population II stars. Stars with masses below 140 solar masses would enrich the intergalactic medium as well as form massive black holes. The coincidence of the Kelvin Helmholtz time with our computed accretion times at about 120 solar masses may argue in favor of such smaller masses. These first black holes may well leave the halos in which they formed for even rather modest kick velocities >~ 10 km/s. Nevertheless, up to about one hundred thousand of these first black holes may remain in the Milky Way. The realization that structure formation began within one hundred million years after big bang makes it difficult to study observationally these first crucial steps. Future observatories have hence to focus on larger collecting areas and wavelengths for which the universe is transparent up to redshifts of 30. XEUS offers the chance to open a new window to these so far dark ages. The limiting masses quoted here rely on stellar models of primordial stars that do not include rotation, magnetic fields or mass loss and hence are somewhat uncertain.

  6. The Black Hole Universe Model

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi

    2014-06-01

    The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin

  7. No supermassive black hole in M33?

    PubMed

    Merritt, D; Ferrarese, L; Joseph, C L

    2001-08-10

    We observed the nucleus of M33, the third-brightest galaxy in the Local Group, with the Space Telescope Imaging Spectrograph at a resolution at least a factor of 10 higher than previously obtained. Rather than the steep rise expected within the radius of gravitational influence of a supermassive black hole, the random stellar velocities showed a decrease within a parsec of the center of the galaxy. The implied upper limit on the mass of the central black hole is only 3000 solar masses, about three orders of magnitude lower than the dynamically inferred mass of any other supermassive black hole. Detecting black holes of only a few thousand solar masses is observationally challenging, but it is critical to establish how supermassive black holes relate to their host galaxies, and which mechanisms influence the formation and evolution of both. PMID:11463879

  8. Influence du chrome et du niobium sur l'équilibre α-γ dans les aluminiures de titane

    NASA Astrophysics Data System (ADS)

    Daloz, D.; Hazotte, A.; Lacaze, J.; Charpentier, M.

    2004-12-01

    L’influence du chrome et du niobium sur les transformations et équilibres de phases des aluminiures de titane dans le domaine biphasé a/g est étudiée par analyse thermique différentielle, dilatomètrie, et métallographie quantitative après traitements thermiques suivis de trempe. Les compositions et les taux de phases à l’équilibre sont déterminés pour différentes températures du domaine biphasé a/g. Les résultats sont comparés aux calculs thermodynamiques réalisés à l’aide d’une banque de données relative aux intermétalliques de base Ti-Al.

  9. The Evaluation of a Modified Chrome Oxide Based High Temperature Solid Lubricant Coating for Foil Gas Bearings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Chris

    1998-01-01

    This paper describes the friction and wear performance of PS304, a modified chrome oxide based coating, for foil gas bearings. PS304 contains 60 wt% NiCr binder, 20 wt% Cr2O3 hardener, and 10 wt% each Ag, and BaF2/CaF2 lubricants. For evaluation, the coating is plasma spray deposited onto test journals which are slid against a superalloy partial arc foil bearing. The test load was 10 KPa (1.5 psi) and the bearings were run under start/stop cyclic conditions. The data show good wear performance of the bearing, especially at temperatures above 25 deg. C. Bearing friction was moderate (micron approx. or equal to 0.4) over the entire temperature range. Based upon the results obtained, the PS304 coating has promise for high temperature, oil-free turbomachinery applications.

  10. Thermodynamic Assessment of Chrome-Spinel Formation in Laser-Sintered Coatings with Cr2O3 Particles

    NASA Astrophysics Data System (ADS)

    Krivilyov, Mikhail; Kharanzhevskiy, Evgeny; Reshetnikov, Sergey; Beyers, Lesley J.

    2016-06-01

    Formation of a thin passive layer has been performed using short pulse laser dispersion of Cr2O3 particles in a C22 steel substrate. As a result, the coating's corrosion resistance is substantially improved compared to unprocessed samples. Microstructure analysis by TEM, XPS, and XRD showed that laser processing leads to dissolution of Cr2O3 with formation of Cr and Fe oxides, chrome-spinel, and metallic Cr dispersed in alpha and gamma Fe. Thermodynamic assessment revealed that the formation of pure chromium is caused by reduction of Cr2O3 and oxidation of iron. This reaction is promoted by shifting of chemical equilibrium at elevated temperatures in the molten zone under short pulse laser processing.

  11. Removal of Cr(III) from chrome tanning wastewater by adsorption using two natural carbonaceous materials: Eggshell and powdered marble.

    PubMed

    Elabbas, Saliha; Mandi, Laila; Berrekhis, Fatima; Pons, Marie Noelle; Leclerc, Jean Pierre; Ouazzani, Naaila

    2016-01-15

    In the present paper, eggshell and powdered marble, two carbonaceous materials, were used to remove Cr(III) ions from a real chrome tanning wastewater. The effects of initial effluent pH, adsorbent dose, contact time and temperature were studied. The maximum uptake of chromium ions was obtained at pH 5.0 with the dose 20 g L(-1) and 12 g L(-1) for eggshell and powdered marble respectively. Adsorption equilibrium was reached after 14 h contact time for eggshell and only after 30 min for powdered marble. Under these conditions, almost 99% Cr(III) was removed from chrome tanning wastewater having an initial concentration of chromium of 3.21 g L(-1). Kinetic data were satisfactorily described by a pseudo-second order chemical sorption model. The equilibrium rate constant was notably greater for powdered marble than for eggshell with 1.142·10(-3) (g mg(-1) min(-1)) and 0.041·10(-3) (g mg(-1) min(-1)) respectively. The adsorption isotherm were well described by a Langmuir model and showed that the interaction of chromium with the two adsorbents surface is a localized monolayer adsorption with a smaller energy constant for the powdered marble than for eggshell (0.020 (L mg(-1)) and 0.083 (L mg(-1)) respectively). The powdered marble was able to adsorb faster a large amount of Cr (III) in comparison to eggshell. The use of a standardized lettuce seed bioassay allowed evaluating a better effectiveness of the Cr adsorption on the powdered marble, removing up to 40% of the treated effluent toxicity than by eggshell 25%. The powdered marble could be considered as an effective, low cost carbonaceous material to be used for chromium removal from tanning wastewater.

  12. Removal of Cr(III) from chrome tanning wastewater by adsorption using two natural carbonaceous materials: Eggshell and powdered marble.

    PubMed

    Elabbas, Saliha; Mandi, Laila; Berrekhis, Fatima; Pons, Marie Noelle; Leclerc, Jean Pierre; Ouazzani, Naaila

    2016-01-15

    In the present paper, eggshell and powdered marble, two carbonaceous materials, were used to remove Cr(III) ions from a real chrome tanning wastewater. The effects of initial effluent pH, adsorbent dose, contact time and temperature were studied. The maximum uptake of chromium ions was obtained at pH 5.0 with the dose 20 g L(-1) and 12 g L(-1) for eggshell and powdered marble respectively. Adsorption equilibrium was reached after 14 h contact time for eggshell and only after 30 min for powdered marble. Under these conditions, almost 99% Cr(III) was removed from chrome tanning wastewater having an initial concentration of chromium of 3.21 g L(-1). Kinetic data were satisfactorily described by a pseudo-second order chemical sorption model. The equilibrium rate constant was notably greater for powdered marble than for eggshell with 1.142·10(-3) (g mg(-1) min(-1)) and 0.041·10(-3) (g mg(-1) min(-1)) respectively. The adsorption isotherm were well described by a Langmuir model and showed that the interaction of chromium with the two adsorbents surface is a localized monolayer adsorption with a smaller energy constant for the powdered marble than for eggshell (0.020 (L mg(-1)) and 0.083 (L mg(-1)) respectively). The powdered marble was able to adsorb faster a large amount of Cr (III) in comparison to eggshell. The use of a standardized lettuce seed bioassay allowed evaluating a better effectiveness of the Cr adsorption on the powdered marble, removing up to 40% of the treated effluent toxicity than by eggshell 25%. The powdered marble could be considered as an effective, low cost carbonaceous material to be used for chromium removal from tanning wastewater. PMID:26598282

  13. REDSHIFT 6.4 HOST GALAXIES OF 10{sup 8} SOLAR MASS BLACK HOLES: LOW STAR FORMATION RATE AND DYNAMICAL MASS

    SciTech Connect

    Willott, Chris J.; Omont, Alain; Bergeron, Jacqueline

    2013-06-10

    We present Atacama Large Millimeter Array observations of rest-frame far-infrared continuum and [C II] line emission in two z = 6.4 quasars with black hole masses of Almost-Equal-To 10{sup 8} M{sub Sun }. CFHQS J0210-0456 is detected in the continuum with a 1.2 mm flux of 120 {+-} 35 {mu}Jy, whereas CFHQS J2329-0301 is undetected at a similar noise level. J2329-0301 has a star formation rate limit of <40 M{sub Sun} yr{sup -1}, considerably below the typical value at all redshifts for this bolometric luminosity. Through comparison with hydro simulations, we speculate that this quasar is observed at a relatively rare phase where quasar feedback has effectively shut down star formation in the host galaxy. [C II] emission is also detected only in J0210-0456. The ratio of [C II] to far-infrared luminosity is similar to that of low-redshift galaxies of comparable luminosity, suggesting that the previous finding of an offset in the relationships between this ratio and far-infrared luminosity at low and high redshifts may be partially due to a selection effect due to the limited sensitivity of previous continuum data. The [C II] line of J0210-0456 is relatively narrow (FWHM = 189 {+-} 18 km s{sup -1}), indicating a dynamical mass substantially lower than expected from the local black hole-velocity dispersion correlation. The [C II] line is marginally resolved at 0.''7 resolution with the blue and red wings spatially offset by 0.''5 (3 kpc) and a smooth velocity gradient of 100 km s{sup -1} across a scale of 6 kpc, possibly due to the rotation of a galaxy-wide disk. These observations are consistent with the idea that stellar mass growth lags black hole accretion for quasars at this epoch with respect to more recent times.

  14. An Ultra-luminous Quasar at z = 5.363 with a Ten Billion Solar Mass Black Hole and a Metal-rich DLA at z ∼ 5

    NASA Astrophysics Data System (ADS)

    Wang, Feige; Wu, Xue-Bing; Fan, Xiaohui; Yang, Jinyi; Cai, Zheng; Yi, Weimin; Zuo, Wenwen; Wang, Ran; McGreer, Ian D.; Ho, Luis C.; Kim, Minjin; Yang, Qian; Bian, Fuyan; Jiang, Linhua

    2015-07-01

    We report the discovery of an ultra-luminous quasar J030642.51+185315.8 (hereafter J0306+1853) at redshift 5.363, which hosts a supermassive black hole with {M}{BH}=(1.07+/- 0.27)× {10}10 {M}ȯ . With an absolute magnitude {M}1450=-28.92 and a bolometric luminosity {L}{bol}∼ 3.4× {10}14{L}ȯ , J0306+1853 is one of the most luminous objects in the early universe. It is not likely to be a beamed source based on its small flux variability, low radio loudness, and normal broad emission lines. In addition, a z=4.986 damped Lyα system (DLA) with [{{M}}/{{H}}]=-1.3+/- 0.1, among the most metal-rich DLAs at z≳ 5, is detected in the absorption spectrum of this quasar. This ultra-luminous quasar puts strong constraints on the bright end of the quasar luminosity function and massive end of the black hole mass function. It will provide a unique laboratory for the study of BH growth and the co-evolution between a BH and the host galaxy with multi-wavelength follow-up observations. The future high-resolution spectra will give more insight into the DLA and other absorption systems along the line of sight of J0306+1853.

  15. Black Lawyers

    ERIC Educational Resources Information Center

    Ware, Gilbert

    1977-01-01

    Notes that blacks are destined to remain strangers in the land of opportunity and in the system of justice, except as persons suspected, accused, arrested, prosecuted, imprisoned, executed--all in disproportionate numbers. (Author/AM)

  16. Black tea

    MedlinePlus

    ... flow. Some people use black tea for preventing tooth decay and kidney stones. In combination with various other ... that men who get more phytoestrogens in their diet have a lower risk of developing lung cancer ...

  17. Black psyllium

    MedlinePlus

    Herbs and supplements that might lower blood sugarBlack psyllium might decrease blood sugar by decreasing how much ... absorbs from foods. Taking it along with other herbs and supplements that might also lower blood sugar ...

  18. Solar thermoelectric generator

    DOEpatents

    Toberer, Eric S.; Baranowski, Lauryn L.; Warren, Emily L.

    2016-05-03

    Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. A novel detailed balance model for STEGs is provided and applied to both state-of-the-art and idealized materials. STEGs can produce electricity by using sunlight to heat one side of a thermoelectric generator. While concentrated sunlight can be used to achieve extremely high temperatures (and thus improved generator efficiency), the solar absorber also emits a significant amount of black body radiation. This emitted light is the dominant loss mechanism in these generators. In this invention, we propose a solution to this problem that eliminates virtually all of the emitted black body radiation. This enables solar thermoelectric generators to operate at higher efficiency and achieve said efficient with lower levels of optical concentration. The solution is suitable for both single and dual axis solar thermoelectric generators.

  19. The Crisis in Black and Black.

    ERIC Educational Resources Information Center

    Hutchinson, Earl Ofari

    These essays explore why the historic conflict between blacks and whites in the United States has become a crisis that divides many African Americans. The changing racial dynamic is not marked by conflicts. between the black middle class and the poor, black men and women, the black intellectual elite and rappers, black politicians and the urban…

  20. Hexavalent Chrome Free Coatings for Electronics Electromagnetic Interference (EMI) Shielding Effectiveness (SE) Interim Test Report

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2015-01-01

    Test specimen configuration was provided by Parker Chomerics. The EMI gasket used in this project was Cho-Seal 6503E. Black oxide alloy steel socket head bolts were used to hold the plates together. Non-conductive spacers were used to control the amount of compression on the gaskets. The following test fixture specifications were provided by Parker Chomerics. The CHO-TP09 test plate sets selected for this project consist of two aluminum plates manufactured to the specifications detailed in CHO­-TP09. The first plate, referred to as the test frame, is illustrated in Figure 1. The test frame is designed with a cutout in the center and two alternating bolt patterns. One pattern is used to bolt the test frame to the corresponding test cover plate (Figure 2), forming a test plate set. The second pattern accepts the hardware used to mount the fully assembled test plate set to the main adapter plate (Figure 3).

  1. When Charged Black Holes Merge

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-08-01

    necessary to produce each phenomenon. For a 10-solar-mass black hole, he finds that the merger can generate a fast radio burst if the black holes charge is more than ~1012 Coulombs (roughly one billion times the charge that travels through a AA battery from full to empty). If its charge is more than ~1016 Coulombs, it can generate a gamma-ray burst.Limits on ChargeZhangs calculations are not just useful in the hypothetical scenario where black holes are charged. They could, in fact, be a way of testing whether black holes are charged.As we accumulate future gravitational-wave observations (and with two observations by LIGO already announced, it seems likely that there will be many more), we will grow a larger sample of follow-up observations in radio through gamma-ray wavelengths. Our detections or our lack of detections of fast radio bursts or gamma-ray bursts associated with these black-hole mergers will allow us to set some of the first real limits on the charge of black holes.CitationBing Zhang 2016 ApJ 827 L31. doi:10.3847/2041-8205/827/2/L31

  2. Energy from solar balloons

    SciTech Connect

    Grena, Roberto

    2010-04-15

    Solar balloons are hot air balloons in which the air is heated directly by the sun, by means of a black absorber. The lift force of a tethered solar balloon can be used to produce energy by activating a generator during the ascending motion of the balloon. The hot air is then discharged when the balloon reaches a predefined maximum height. A preliminary study is presented, along with an efficiency estimation and some considerations on possible realistic configurations. (author)

  3. Evidences for Black Hole Formation by Complete Stellar Collapse

    NASA Astrophysics Data System (ADS)

    Mirabel, Igor Felix

    2016-07-01

    One of the most critical parameters that determines the formation of binary black holes is the range of masses of black holes that may form by direct collapse, namely, with no energetic supernova kicks that would unbound the stellar binary. Theoretical models set mass ranges and limits for black hole formation through the complete collapse of the stellar progenitor. However, observational constraints for those mass limits have been elusive. Since the velocity of a stellar black hole encodes the history of its formation and evolution, it may provide observational constraints on the strength of kicks by natal supernova explosions in the formation of the black hole. Based on the motion in three dimensions of five black hole binaries in our Galaxy it is found that the three black holes with < 10 solar masses are runaway black hole binaries due to kicks from natal supernovae, whereas the two black holes with 10 to 15 solar masses remained in their birth place and must have been form by complete or almost complete collapse of the progenitor star. These observations show that there may be binary black holes with components having masses as low as 10 solar masses, which suggests that a significant fraction of massive stellar binaries would end as black hole binaries that would produce a large stochastic gravitational-wave background.

  4. Black Literature vs. Black Studies: Three Lynchings

    ERIC Educational Resources Information Center

    Williams, Melvin G.

    1977-01-01

    Considers three works by black authors, all dealing with lynchings, that may be used in a black literature course to introduce students to the esthetic dimension of black literature, as well as to its cultural and racial significance. (GW)

  5. Radio Detections During Two State Transitions of the Intermediate-Mass Black Hole HLX-1

    NASA Technical Reports Server (NTRS)

    Webb, Natalie; Cseh, David; Lenc, Emil; Godet, Olivier; Barret, Didier; Corbel, Stephane; Farrell, Sean; Fender, Robert; Gehrels, Neil; Heywood, Ian

    2012-01-01

    Relativistic jets are streams of plasma moving at appreciable fractions of the speed of light. They have been observed from stellar-mass black holes (approx. 3 to 20 solar masses) as well as supermassive black holes (approx.. 10(exp 6) to 10(exp 9) Solar Mass) found in the centers of most galaxies. Jets should also be produced by intermediate-mass black holes (approx. 10(exp 2) to 10(exp 5) Solar Mass), although evidence for this third class of black hole has, until recently, been weak. We report the detection of transient radio emission at the location of the intermediate-mass black hole candidate ESO 243-49 HLX-1, which is consistent with a discrete jet ejection event. These observations also allow us to refine the mass estimate of the black hole to be between approx. 9 × 10(exp 3) Solar Mass and approx. 9 × 10(exp 4) Solar Mass.

  6. Counseling Blacks

    ERIC Educational Resources Information Center

    Vontress, Clemmont E.

    1970-01-01

    Blacks have developed unique environmental perceptions, values, and attitudes, making it difficult for counselors to establish and maintain positive rapport. This article examines attitudinal ingredients posited by Carl Rogers for relevance to this problem, and suggests in-service training to help counselors and other professionals relate…

  7. Black Cohosh

    MedlinePlus

    ... from the Women's Health Initiative randomized controlled trial. Journal of the American Medical Association 288: 321-333, 2002. [ PubMed abstract ] Gunn TR, Wright IM: The use of black and blue cohosh in labour. New Zealand Medical Journal 109: 410-411, 1996. [ PubMed abstract ] Finkle RS, ...

  8. Black English.

    ERIC Educational Resources Information Center

    Bailey, Charles-James N.

    This paper, presented as part of a military lecture series given by the Division of Continuing Education and Community Service Speakers' Bureau of the University of Hawaii to military personnel at Schofield Barracks and Fort Shafter, investigates the origins and present status of Black English. A discussion of early studies in the Gullah dialect…

  9. Black Adolescents.

    ERIC Educational Resources Information Center

    Jones, Reginald L., Ed.

    This volume presents an overview of contemporary black adolescents from social, psychological, economic, educational, medical, historical, and comparative perspectives, with most emphasizing the roles that race, socioeconomic status, and environmental forces play in this critical period. The volume includes 19 chapters by various authors arranged…

  10. Black Hills

    Atmospheric Science Data Center

    2014-05-15

    article title:  Drought in the Black Hills     View ... and western South Dakota remain in the midst of a severe drought. This set of images and maps from NASA's Multi-angle Imaging ... the 2000 and 2004 dates. As the vegetation faded with the drought, the  albedo  at the surface increased. Albedo measures the ...

  11. Black America.

    ERIC Educational Resources Information Center

    San Francisco Unified School District, CA.

    This is a selected bibliography of some good and some outstanding audio-visual educational materials in the library of the Educational Materials Bureau, Audio-Visual Education Section, that may be considered by particular interest in the study of black Americans. The bibliography is arranged alphabetically within these subject areas: I. African…

  12. Solar industrial process heat: A study of applications and attitudes

    NASA Astrophysics Data System (ADS)

    Wilson, V.

    1981-04-01

    Data were gathered through site visits to 100 industrial plants. The site specific data suggests several possible near term market opportunities for solar thermal energy systems. Plants using electricity as their primary fuel for industrial process heat were identified, on the basis of their high fuel prices, as attractive early entry markets for solar energy. Additional opportunities were reflected in plants that had accomplished much of their conservation plans, or bad sizeable percentages of their operating budgets committed to energy expenses. A suitability analysis identified eleven industrial plants as highly suitable for solar thermal applications, they included producers of fluid milk, pottery, canned and bottled soft drinks, fabricated structural metal, refined petroleum, aluminum cans, chrome and nickel plating and stamped frame metal and metal finishings.

  13. A review on management of chrome-tanned leather shavings: a holistic paradigm to combat the environmental issues.

    PubMed

    Pati, Anupama; Chaudhary, Rubina; Subramani, Saravanabhavan

    2014-10-01

    Raw hide/skins come to the tanners as a by-product of meat industry which is converted into value-added leather as product for fashion market. Leather manufacturing is a chemical process of natural biological matrix. It employs a huge quantity of water and inorganic and organic chemicals for processing and thereby discharges solid and liquid wastes into the environment. One of the potential solid wastes generated from leather industry is chrome-tanned leather shavings (CTLSs), and its disposal is increasingly becoming a huge challenge on disposal to tanners due to presence of heavy metal chromium. Hence, finding a sustainable solution to the CTLS disposal problem is a prime challenge for global tanners and researchers. This paper aims to the deeper review of various disposal methods on CTLS such as protein, chromium, and energy recovery processes and its utilization methodologies. Sustainable technologies have been developed to overcome CTLS solid wastes emanating from leather processing operations. Further, this review paper brings a broader classification of developed methodologies for treatment of CTLSs. PMID:24906828

  14. The potential application of a Cobalt Chrome Molybdenum femoral stem with functionally graded orthotropic structures manufactured using Laser Melting technologies.

    PubMed

    Hazlehurst, K B; Wang, C J; Stanford, M

    2013-12-01

    The cementless fixation of porous coated femoral stems is a common technique employed for Total Hip Arthroplasty (THA). With the rate of revision surgery appearing to rise and younger more active patients requiring primary surgery it can be thought that alternative methods for increasing implant longevity need to be considered. The stress shielding of periprosthetic bone still remains a contributing factor to implant loosening, caused through a mismatch in stiffness between the implant and the bone. However, the ability to achieve stiffness matching characteristics is being realised through the use of Additive Layer Manufacturing (ALM) technologies and Functionally Graded Materials (FGM). This paper proposes an alternative design methodology for a monoblock Cobalt Chrome Molybdenum (CoCrMo) femoral stem. It hypothesises that a femoral stem suitable for cementless fixation can be manufactured using Laser Melting (LM) technology offering orthotropic functionally graded porous structures with similar mechanical properties to human bone. The structure and mechanical properties of the natural femur have been used as a basis for the design criteria which hypothesises that through a combination of numerical analysis and physical testing, an optimal design can be proposed to provide a lightweight, customised femoral stem that can reduce the risk of implant loosening through stress shielding whilst maintaining bone-implant interface stability.

  15. A review on management of chrome-tanned leather shavings: a holistic paradigm to combat the environmental issues.

    PubMed

    Pati, Anupama; Chaudhary, Rubina; Subramani, Saravanabhavan

    2014-10-01

    Raw hide/skins come to the tanners as a by-product of meat industry which is converted into value-added leather as product for fashion market. Leather manufacturing is a chemical process of natural biological matrix. It employs a huge quantity of water and inorganic and organic chemicals for processing and thereby discharges solid and liquid wastes into the environment. One of the potential solid wastes generated from leather industry is chrome-tanned leather shavings (CTLSs), and its disposal is increasingly becoming a huge challenge on disposal to tanners due to presence of heavy metal chromium. Hence, finding a sustainable solution to the CTLS disposal problem is a prime challenge for global tanners and researchers. This paper aims to the deeper review of various disposal methods on CTLS such as protein, chromium, and energy recovery processes and its utilization methodologies. Sustainable technologies have been developed to overcome CTLS solid wastes emanating from leather processing operations. Further, this review paper brings a broader classification of developed methodologies for treatment of CTLSs.

  16. Thermal behaviour of chrome shavings and of sludges recovered after digestion of tanned solid wastes with calcium hydroxide

    SciTech Connect

    Tahiri, S. . E-mail: t_soufiane@yahoo.fr; Albizane, A.; Messaoudi, A.; Azzi, M.; Bennazha, J.; Younssi, S. Alami; Bouhria, M.

    2007-07-01

    The thermal behaviour of chrome shavings and of sludges recovered after digestion of tanned wastes with Ca(OH){sub 2} was studied. Ashes obtained after incineration of wastes at various temperatures were analysed by X-ray diffraction and EDX method. The main crystallized phases present in the ash obtained at 600 deg. C are Cr{sub 2}O{sub 3} and NaCl. The diffractograms revealed an increase in the intensities of the chromium oxide peaks and a very notable decrease of the amount of sodium chloride at 1100 deg. C. EDX analysis revealed a total disappearance of the chlorine peak at this temperature. Scanning electron micrographs show that the waste lost its fibrous aspect when the temperature increases. Formation of aggregates was noted after 550 deg. C. Combustion of organic matters and decarbonation phenomenon are the main stages observed on GTA and DTA curves of sludges. These phenomena are, respectively, exothermic and endothermic. The diffractogram of sludges recorded at 550 deg. C, in the presence of a constant oxygen surplus, revealed the presence of CaCrO{sub 4} and CaCO{sub 3}.

  17. Gamma rays from accretion onto rotating black holes

    NASA Technical Reports Server (NTRS)

    Collins, M. S.

    1979-01-01

    Ionized matter falling onto an isolated rotating black hole will be heated sufficiently that proton-proton collisions will produce mesons, including neutral pions, which decay into gamma rays. For massive (1000-solar mass) black holes, the resulting gamma-ray luminosity may exceed 10 to the 36th erg/s with a spectrum peaked near 20 MeV.

  18. A comparison of Staphylococcus aureus biofilm formation on cobalt-chrome and titanium-alloy spinal implants.

    PubMed

    Patel, Shalin S; Aruni, Wilson; Inceoglu, Serkan; Akpolat, Yusuf T; Botimer, Gary D; Cheng, Wayne K; Danisa, Olumide A

    2016-09-01

    The use of cobalt chrome (CoCr) implants in spinal surgery has become increasingly popular. However, there have been no studies specifically comparing biofilm formation on CoCr with that of titanium-alloy spinal implants. The objective of this study was to compare the difference in propensity for biofilm formation between these two materials, as it specifically relates to spinal rods. Staphylococcus aureus subsp. Aureus (ATCC 6538) were incubated with two different types of spinal rods composed of either CoCr or titanium-alloy. The spinal rods were then subject to a trypsin wash to allow for isolation of the colonized organism and associated biofilms. The associated optical density values (OD) from the bacterial isolates were obtained and the bacterial solutions were plated on brain-heart infusion agar plates and the resultant colony-forming units (CFU) were counted. The OD values for the titanium-alloy rods were 1.105±0.096nm (mean±SD) and 1.040±0.026nm at 48hours and 96hours, respectively. In contrast, the OD values for the CoCr rods were 1.332±0.161nm and 1.115±0.207nm at 48 and 96hours, respectively (p<0.05). The CFU values were 1481±417/100mm(2) and 745±159/100mm(2) at 48 and 96hours, respectively for the titanium-alloy group. These values were significantly lower than the CFU values obtained from the CoCr group which were 2721±605/100mm(2) and 928±88/100mm(2) (p<0.001) at both 48 and 96hours respectively. Our findings, evaluating both the OD and CFU values, indicate that implants composed of CoCr had a higher proclivity towards biofilm formation compared to titanium-alloy implants. PMID:27396378

  19. A comparison of Staphylococcus aureus biofilm formation on cobalt-chrome and titanium-alloy spinal implants.

    PubMed

    Patel, Shalin S; Aruni, Wilson; Inceoglu, Serkan; Akpolat, Yusuf T; Botimer, Gary D; Cheng, Wayne K; Danisa, Olumide A

    2016-09-01

    The use of cobalt chrome (CoCr) implants in spinal surgery has become increasingly popular. However, there have been no studies specifically comparing biofilm formation on CoCr with that of titanium-alloy spinal implants. The objective of this study was to compare the difference in propensity for biofilm formation between these two materials, as it specifically relates to spinal rods. Staphylococcus aureus subsp. Aureus (ATCC 6538) were incubated with two different types of spinal rods composed of either CoCr or titanium-alloy. The spinal rods were then subject to a trypsin wash to allow for isolation of the colonized organism and associated biofilms. The associated optical density values (OD) from the bacterial isolates were obtained and the bacterial solutions were plated on brain-heart infusion agar plates and the resultant colony-forming units (CFU) were counted. The OD values for the titanium-alloy rods were 1.105±0.096nm (mean±SD) and 1.040±0.026nm at 48hours and 96hours, respectively. In contrast, the OD values for the CoCr rods were 1.332±0.161nm and 1.115±0.207nm at 48 and 96hours, respectively (p<0.05). The CFU values were 1481±417/100mm(2) and 745±159/100mm(2) at 48 and 96hours, respectively for the titanium-alloy group. These values were significantly lower than the CFU values obtained from the CoCr group which were 2721±605/100mm(2) and 928±88/100mm(2) (p<0.001) at both 48 and 96hours respectively. Our findings, evaluating both the OD and CFU values, indicate that implants composed of CoCr had a higher proclivity towards biofilm formation compared to titanium-alloy implants.

  20. Contemporary Black Theatre.

    ERIC Educational Resources Information Center

    Thomas, Pearl

    The distinguishable black theatre in America, mirroring a distinguishable black experience, is an artistic product which demands audience involvement. Both the Afro-American oral tradition and the art of gesture are integral aspects of black theatre. In addition, the tragedy found black theatre is not tragedy in the classic sense, as blacks feel…

  1. Smoking Cessation among Blacks.

    ERIC Educational Resources Information Center

    Stotts, R. Craig; And Others

    1991-01-01

    Lung cancer is a serious health problem among blacks, with a mortality rate of 119 per 100,000 black males, compared to 81 per 100,000 for white males. Smoking cessation efforts are most successful when tailored to the black community, using black community networks and broadcast media for black audiences. (SLD)

  2. Solar pond

    NASA Technical Reports Server (NTRS)

    Miller, C. G.; Stephens, J. B. (Inventor)

    1978-01-01

    Shallow pools of liquid to collect low-temperature solar generated thermal energy are described. Narrow elongated trenches, grouped together over a wide area, are lined with a heat-absorbing black liner. The heat-absorbing liquid is kept separate from the thermal energy removing fluid by means such as clear polyethylene material. The covering for the pond may be a fluid or solid. If the covering is a fluid, fire fighting foam, continuously generated, or siloons are used to keep the surface covering clean and insulated. If the thermal energy removing fluid is a gas, a fluid insulation layer contained in a flat polyethlene tubing is used to cover the pond. The side of the tube directed towards the sun is treated to block out ultraviolet radiation and trap in infrared radiation.

  3. Solar astronomy

    NASA Technical Reports Server (NTRS)

    Rosner, Robert; Noyes, Robert; Antiochos, Spiro K.; Canfield, Richard C.; Chupp, Edward L.; Deming, Drake; Doschek, George A.; Dulk, George A.; Foukal, Peter V.; Gilliland, Ronald L.

    1991-01-01

    An overview is given of modern solar physics. Topics covered include the solar interior, the solar surface, the solar atmosphere, the Large Earth-based Solar Telescope (LEST), the Orbiting Solar Laboratory, the High Energy Solar Physics mission, the Space Exploration Initiative, solar-terrestrial physics, and adaptive optics. Policy and related programmatic recommendations are given for university research and education, facilitating solar research, and integrated support for solar research.

  4. Why Black-on-Black Homicide?

    ERIC Educational Resources Information Center

    Jeff, Morris F. X., Jr.

    1981-01-01

    The causes of homicides committed against Blacks by Blacks are examined. Major preventive measures are said to be equal opportunity, better jobs, reduction of racial discrimination, elimination of organized crime, removal of drugs from community, and better schools. (JCD)

  5. The Australian Geographic Team Marsupial solar-powered car

    SciTech Connect

    Allen, G.R.; Storey, J.W.V.

    1988-01-01

    As in all vehicles of this type, low weight and aerodynamic drag must be achieved without compromising safety, and in an extremely rugged structure. This has been done by using a chrome-molybdenum steel space-frame, surrounded by a Kevlar/foam sandwich body shell. The solar panel wing, which uses a laminar flow section to obtain low drag, does not tilt except when the vehicle is stationary. A high degree of redundancy is built into the vehicle; for example there are two motors and transmissions, the solar array is divided into seven parallel sub-arrays, and the power electronics is multiply redundant. Built entirely in the garage of a suburban house, the Australian Geographic Team Marsupial car cost less than US$50,000 to construct.

  6. Solar heated vacuum flask

    SciTech Connect

    Posnansky, M.

    1980-04-08

    The wall of a protective jacket of a vacuum flask, containing a double-walled vessel whose walls are permeable to solar radiation , includes parts capable of being swung open. These parts and a wall part situated between them each have a reflective coating. The reflective surfaces of these coatings, viewed in crosssection, extend along a parabola when the movable wall parts are opened out, so that incident solar radiation is collected in the core zone of the vessel. A solar-radiation absorbing member may be disposed in this core zone, E.G., a metal tube having a black outer surface. Liquid contents of such a vacuum flask can be heated by means of solar energy.

  7. Black Hole Observations - Towards the Event Horizon

    NASA Astrophysics Data System (ADS)

    Britzen, Silke

    Black Holes are probably the most elusive solutions of Einstein's theory of General Relativity. Despite numerous observations of the direct galactic environment and indirect influence of astrophysical black holes (e.g. jets, variable emission across the wavelength spectrum, feedback processes, etc.) -- a direct proof of their existence is still lacking. This article highlights some aspects deduced from many observations and concentrates on the experimental results with regard to black holes with masses from millions to billions of solar masses. The focus will be on the challenges and remaining questions. The Event Horizon Telescopce (EHT) project to image the photon sphere of Sgr A* and its potential is briefly sketched. This instrumental approach shall lead to highest resolution observations of the supermassive black hole at the center of the Milky Way (Sgr A*).

  8. Detection of hazardous pollutants in chrome-tanned leather using locally developed laser-induced breakdown spectrometer.

    PubMed

    Nasr, M M; Gondal, Mohammed Asharf; Seddigi, Z S

    2011-04-01

    Highly toxic contaminants like Cr, As, and Pb were detected in chrome-tanning process of animal skin to produce leather by applying locally developed laser-induced breakdown spectrometer. An Nd-YAG laser with 1,064 nm wavelength was focused on the surface of leather samples (natural and manufactured) to generate a plasma spark and spectrally resolved spectra were used for identification and quantification of contaminants. The leather samples were collected from a tannery located in industrial cities of Riyadh and Jeddah, Saudi Arabia. The study was carried out on fully, half manufactured (wet blue leather), and natural hide (skin). To the best of our knowledge, this is the first attempt where laser-induced breakdown spectroscopy (LIBS) technique has been applied for the analysis of leather before and after tanning process. The maximum concentration of different elements of environmental significance like chromium, lead, arsenic, sulfur, magnesium were 199, 289, 31, 38, and 39 ppm, respectively, in one of the manufactured leather samples. The limit of detection (LOD) of our LIBS system for chromium, lead, arsenic, sulfur, and magnesium were 2, 3, 1.5,7, and 3 ppm, respectively. The safe permissible limit for tanned leather for highly toxic elements like chromium, lead, and arsenic are 1, 0.5, 0.01 ppm, respectively, as prescribed in Environmental Regulation Standards for Saudi Industries set by Royal Commission Jubail, Saudi Arabia. The LIBS technique is superior to other conventional techniques like ICP or atomic absorption that a little or no sample preparation is required, no chemicals are needed, multi-elemental analysis is possible for all kinds of samples (natural and anthropogenic materials), microgram of sample is essential, and LIBS could be applied for remote analysis. It is highly selective and sensitivity higher than ICP, and as no sample and chemicals are required, it is cost effective for multi-sample analysis per unit time as compared with other

  9. Deposition Technique For Chemical Free Black Coatings On Metals

    NASA Astrophysics Data System (ADS)

    Carton, J. G.; Cobbe, N.; O'Donoghue, J.; Pambaguian, L.; Norman, A.; Liedtke, V.; McCaul, T.

    2012-07-01

    Coatings having specific thermo-optical properties are necessary to manage the temperature equilibrium in space hardware. Incumbent black body coatings have a need to extend their operating temperature as well as increase the range of substrate materials that can be coated; in addition, issues relating to outgassing can limit the application of black body coatings. In this paper a relatively new coating technology, CoBlast, is used to deposit material on to titanium substrates, to produce a black body surface; SolarBlack. CoBlast, replaces the oxide layer of reactive metals with a fused thin surface. The process is uniquely non-complex, requiring no thermal input, no wet chemistry and is performed in an ambient temperature and pressure environment. Thermo optical and micro-structure analysis of SolarBlack was completed and the characterisation results including thermo cycling, up to 700°C, are discussed.

  10. Kinetic model of the thermal pyrolysis of chrome tanned leather treated with NaOH under different conditions using thermogravimetric analysis.

    PubMed

    Bañón, E; Marcilla, A; García, A N; Martínez, P; León, M

    2016-02-01

    The thermal decomposition of chrome tanned leather before and after a soaking treatment with NaOH was studied using thermogravimetric analysis (TGA). The effect of the solution concentration (0.2M and 0.5M) and the soaking time (5min and 15min) was evaluated. TGA experiments at four heating rates (5, 10, 15 and 20°Cmin(-1)) were run in a nitrogen atmosphere for every treatment condition. A kinetic model was developed considering the effect of the three variables studied, i.e.: the NaOH solution concentration, the soaking time and the heating rate. The proposed model for chrome tanned leather pyrolysis involves a set of four reactions, i.e.: three independent nth order reactions, yielding the corresponding products and one of them undergoing a successive cero order reaction. The model was successfully applied simultaneously to all the experimental data obtained. The evaluation of the kinetic parameters obtained (activation energy, pre-exponential factor and reaction order) allowed a better understanding of the effect of the alkali treatment on these wastes.

  11. A numerical investigation into the influence of the properties of cobalt chrome cellular structures on the load transfer to the periprosthetic femur following total hip arthroplasty.

    PubMed

    Hazlehurst, Kevin Brian; Wang, Chang Jiang; Stanford, Mark

    2014-04-01

    Stress shielding of the periprosthetic femur following total hip arthroplasty is a problem that can promote the premature loosening of femoral stems. In order to reduce the need for revision surgery it is thought that more flexible implant designs need to be considered. In this work, the mechanical properties of laser melted square pore cobalt chrome molybdenum cellular structures have been incorporated into the design of a traditional monoblock femoral stem. The influence of incorporating the properties of cellular structures on the load transfer to the periprosthetic femur was investigated using a three dimensional finite element model. Eleven different stiffness configurations were investigated by using fully porous and functionally graded approaches. This investigation confirms that the periprosthetic stress values depend on the stiffness configuration of the stem. The numerical results showed that stress shielding is reduced in the periprosthetic Gruen zones when the mechanical properties of cobalt chrome molybdenum cellular structures are used. This work identifies that monoblock femoral stems manufactured using a laser melting process, which are designed for reduced stiffness, have the potential to contribute towards reducing stress shielding.

  12. Evaluating the Relationship between Slabbing of Cr2O3/MgO Refractories Used in Steelmaking and Spalling of High Chrome Oxide Refractories Used in Gasification

    SciTech Connect

    Bennett, J.P.; Thomas, H.; Kwong, K.-S.

    2006-10-01

    Because of its excellent corrosion resistance and high temperature properties, chrome oxide refractories have been used in a number of severe service environments, including steelmaking and gasification. Refractory failure of Cr2O3/MgO or MgO/Cr2O3 refractories in steelmaking can involve a phenomena called slabbing, peeling, or chemical spalling. A similar failure mechanism exists in the high chrome oxide materials used in gasification. Gasifiers contain the reaction between a carbon feedstock, water, and oxygen under reducing conditions; producing H2 and CO used in chemicals or as fuel for power plants. A slagging gasifier typically operates between 1250- 1575°C, and with pressures between 300-1000 psi. Gasification refractory failure is by chemical dissolution and/or by spalling. Spalling is caused by slag penetration of the porous refractory surface and by expansion differences between the penetrated/non-penetrated areas, and is exacerbated by thermal cycling. Similarities between slabbing of steelmaking refractories and spalling of gasification refractories will be discussed.

  13. Kinetic model of the thermal pyrolysis of chrome tanned leather treated with NaOH under different conditions using thermogravimetric analysis.

    PubMed

    Bañón, E; Marcilla, A; García, A N; Martínez, P; León, M

    2016-02-01

    The thermal decomposition of chrome tanned leather before and after a soaking treatment with NaOH was studied using thermogravimetric analysis (TGA). The effect of the solution concentration (0.2M and 0.5M) and the soaking time (5min and 15min) was evaluated. TGA experiments at four heating rates (5, 10, 15 and 20°Cmin(-1)) were run in a nitrogen atmosphere for every treatment condition. A kinetic model was developed considering the effect of the three variables studied, i.e.: the NaOH solution concentration, the soaking time and the heating rate. The proposed model for chrome tanned leather pyrolysis involves a set of four reactions, i.e.: three independent nth order reactions, yielding the corresponding products and one of them undergoing a successive cero order reaction. The model was successfully applied simultaneously to all the experimental data obtained. The evaluation of the kinetic parameters obtained (activation energy, pre-exponential factor and reaction order) allowed a better understanding of the effect of the alkali treatment on these wastes. PMID:26603567

  14. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  15. Graduating Black Males

    ERIC Educational Resources Information Center

    Bell, Edward Earl

    2010-01-01

    Background: The graduation numbers for Black males are dismal, chilling, and undeniably pathetic. The nation graduates only 47% of Black males who enter the 9th grade. The infusion of federal dollars and philanthropic support will not stop the trajectory of Black males who drop out of school. Black males face an upheaval educational battle;…

  16. Black Teachers on Teaching.

    ERIC Educational Resources Information Center

    Foster, Michele

    The importance to the black community of teaching as a profession can be seen in reference material and other literature about blacks, but this book is unique in presenting the voices of black teachers themselves. The stories of 20 black teachers, born between 1905 and 1973, are told in their own voices. These 20 life interviews collect the…

  17. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  18. Black holes in the early Universe.

    PubMed

    Volonteri, Marta; Bellovary, Jillian

    2012-12-01

    The existence of massive black holes (MBHs) was postulated in the 1960s, when the first quasars were discovered. In the late 1990s their reality was proven beyond doubt in the Milky way and a handful nearby galaxies. Since then, enormous theoretical and observational efforts have been made to understand the astrophysics of MBHs. We have discovered that some of the most massive black holes known, weighing billions of solar masses, powered luminous quasars within the first billion years of the Universe. The first MBHs must therefore have formed around the time the first stars and galaxies formed. Dynamical evidence also indicates that black holes with masses of millions to billions of solar masses ordinarily dwell in the centers of today's galaxies. MBHs populate galaxy centers today, and shone as quasars in the past; the quiescent black holes that we detect now in nearby bulges are the dormant remnants of this fiery past. In this review we report on basic, but critical, questions regarding the cosmological significance of MBHs. What physical mechanisms led to the formation of the first MBHs? How massive were the initial MBH seeds? When and where did they form? How is the growth of black holes linked to that of their host galaxy? The answers to most of these questions are works in progress, in the spirit of these reports on progress in physics.

  19. Black holes in the early Universe

    NASA Astrophysics Data System (ADS)

    Volonteri, Marta; Bellovary, Jillian

    2012-12-01

    The existence of massive black holes (MBHs) was postulated in the 1960s, when the first quasars were discovered. In the late 1990s their reality was proven beyond doubt in the Milky way and a handful nearby galaxies. Since then, enormous theoretical and observational efforts have been made to understand the astrophysics of MBHs. We have discovered that some of the most massive black holes known, weighing billions of solar masses, powered luminous quasars within the first billion years of the Universe. The first MBHs must therefore have formed around the time the first stars and galaxies formed. Dynamical evidence also indicates that black holes with masses of millions to billions of solar masses ordinarily dwell in the centers of today's galaxies. MBHs populate galaxy centers today, and shone as quasars in the past; the quiescent black holes that we detect now in nearby bulges are the dormant remnants of this fiery past. In this review we report on basic, but critical, questions regarding the cosmological significance of MBHs. What physical mechanisms led to the formation of the first MBHs? How massive were the initial MBH seeds? When and where did they form? How is the growth of black holes linked to that of their host galaxy? The answers to most of these questions are works in progress, in the spirit of these reports on progress in physics.

  20. Black holes in the early Universe.

    PubMed

    Volonteri, Marta; Bellovary, Jillian

    2012-12-01

    The existence of massive black holes (MBHs) was postulated in the 1960s, when the first quasars were discovered. In the late 1990s their reality was proven beyond doubt in the Milky way and a handful nearby galaxies. Since then, enormous theoretical and observational efforts have been made to understand the astrophysics of MBHs. We have discovered that some of the most massive black holes known, weighing billions of solar masses, powered luminous quasars within the first billion years of the Universe. The first MBHs must therefore have formed around the time the first stars and galaxies formed. Dynamical evidence also indicates that black holes with masses of millions to billions of solar masses ordinarily dwell in the centers of today's galaxies. MBHs populate galaxy centers today, and shone as quasars in the past; the quiescent black holes that we detect now in nearby bulges are the dormant remnants of this fiery past. In this review we report on basic, but critical, questions regarding the cosmological significance of MBHs. What physical mechanisms led to the formation of the first MBHs? How massive were the initial MBH seeds? When and where did they form? How is the growth of black holes linked to that of their host galaxy? The answers to most of these questions are works in progress, in the spirit of these reports on progress in physics. PMID:23099537

  1. Discovering the Solar System

    NASA Astrophysics Data System (ADS)

    Jones, Barrie W.

    1999-04-01

    Discovering the Solar System Barrie W. Jones The Open University, Milton Keynes, UK Discovering the Solar System is a comprehensive, up-to-date account of the Solar System and of the ways in which the various bodies have been investigated and modelled. The approach is thematic, with sequences of chapters on the interiors of planetary bodies, on their surfaces, and on their atmospheres. Within each sequence there is a chapter on general principles and processes followed by one or two chapters on specific bodies. There is also an introductory chapter, a chapter on the origin of the Solar System, and a chapter on asteroids, comets and meteorites. Liberally illustrated with diagrams, black and white photographs and colour plates, Discovering the Solar System also features: * tables of essential data * question and answers within the text * end of section review questions with answers and comments Discovering the Solar System is essential reading for all undergraduate students for whom astronomy or planetary science are components of their degrees, and for those at a more advanced level approaching the subject for the first time. It will also be of great interest to non-specialists with a keen interest in astronomy. A small amount of scientific knowledge is assumed plus familiarity with basic algebra and graphs. There is no calculus. Praise for this book includes: ".certainly qualifies as an authoritative text. The author clearly has an encyclopedic knowledge of the subject." Meteorics and Planetary Science ".liberally doused with relevant graphs, tables, and black and white figures of good quality." EOS, Transactions of the American Geophysical Union ".one of the best books on the Solar System I have seen. The general accuracy and quality of the content is excellent." Journal of the British Astronomical Association

  2. The Black Holes in the Hearts of Galaxies

    NASA Technical Reports Server (NTRS)

    Rigby, Jane

    2010-01-01

    In the past 20 years, astronomers have discovered that almost every galaxy contains a black hole at its center. These black holes outweigh our sun by a factor of a million to a billion. Surprisingly, there's a very tight connection between the size of the galaxy and its central black hole -- the bigger the galaxy, the bigger the black hole. We don't know why this relationship exists -- how can a black hole, with a sphere of influence the size of our solar system, know what kind of galaxy it inhabits? What processes create this relationship? I'll explore these topics, and show how new space telescopes are helping us discover thousands of black holes and explore how they evolve with time.

  3. The Black Black Woman and the Black Middle Class.

    ERIC Educational Resources Information Center

    Jeffers, Trellie

    1981-01-01

    Reprint of a 1973 article that describes the discrimination that particularly dark-skinned Black women suffer, especially at the hands of a color-conscious Black middle class. Calls for dark women to look to the African appearance and working-class roots as sources of pride and strength. (GC)

  4. Award-Winning Etching Process Cuts Solar Cell Costs (Revised) (Fact Sheet)

    SciTech Connect

    Not Available

    2011-05-01

    The NREL "black silicon" nanocatalytic wet-chemical etch is an inexpensive, one-step method to minimize reflections from crystalline silicon solar cells. The technology enables high-efficiency solar cells without the use of expensive antireflection coatings.

  5. NASA Observatory Confirms Black Hole Limits

    NASA Astrophysics Data System (ADS)

    2005-02-01

    The very largest black holes reach a certain point and then grow no more, according to the best survey to date of black holes made with NASA's Chandra X-ray Observatory. Scientists have also discovered many previously hidden black holes that are well below their weight limit. These new results corroborate recent theoretical work about how black holes and galaxies grow. The biggest black holes, those with at least 100 million times the mass of the Sun, ate voraciously during the early Universe. Nearly all of them ran out of 'food' billions of years ago and went onto a forced starvation diet. Focus on Black Holes in the Chandra Deep Field North Focus on Black Holes in the Chandra Deep Field North On the other hand, black holes between about 10 and 100 million solar masses followed a more controlled eating plan. Because they took smaller portions of their meals of gas and dust, they continue growing today. "Our data show that some supermassive black holes seem to binge, while others prefer to graze", said Amy Barger of the University of Wisconsin in Madison and the University of Hawaii, lead author of the paper describing the results in the latest issue of The Astronomical Journal (Feb 2005). "We now understand better than ever before how supermassive black holes grow." One revelation is that there is a strong connection between the growth of black holes and the birth of stars. Previously, astronomers had done careful studies of the birthrate of stars in galaxies, but didn't know as much about the black holes at their centers. DSS Optical Image of Lockman Hole DSS Optical Image of Lockman Hole "These galaxies lose material into their central black holes at the same time that they make their stars," said Barger. "So whatever mechanism governs star formation in galaxies also governs black hole growth." Astronomers have made an accurate census of both the biggest, active black holes in the distance, and the relatively smaller, calmer ones closer by. Now, for the first

  6. NASA Observatory Confirms Black Hole Limits

    NASA Astrophysics Data System (ADS)

    2005-02-01

    The very largest black holes reach a certain point and then grow no more, according to the best survey to date of black holes made with NASA's Chandra X-ray Observatory. Scientists have also discovered many previously hidden black holes that are well below their weight limit. These new results corroborate recent theoretical work about how black holes and galaxies grow. The biggest black holes, those with at least 100 million times the mass of the Sun, ate voraciously during the early Universe. Nearly all of them ran out of 'food' billions of years ago and went onto a forced starvation diet. Focus on Black Holes in the Chandra Deep Field North Focus on Black Holes in the Chandra Deep Field North On the other hand, black holes between about 10 and 100 million solar masses followed a more controlled eating plan. Because they took smaller portions of their meals of gas and dust, they continue growing today. "Our data show that some supermassive black holes seem to binge, while others prefer to graze", said Amy Barger of the University of Wisconsin in Madison and the University of Hawaii, lead author of the paper describing the results in the latest issue of The Astronomical Journal (Feb 2005). "We now understand better than ever before how supermassive black holes grow." One revelation is that there is a strong connection between the growth of black holes and the birth of stars. Previously, astronomers had done careful studies of the birthrate of stars in galaxies, but didn't know as much about the black holes at their centers. DSS Optical Image of Lockman Hole DSS Optical Image of Lockman Hole "These galaxies lose material into their central black holes at the same time that they make their stars," said Barger. "So whatever mechanism governs star formation in galaxies also governs black hole growth." Astronomers have made an accurate census of both the biggest, active black holes in the distance, and the relatively smaller, calmer ones closer by. Now, for the first

  7. Surfing a Black Hole

    NASA Astrophysics Data System (ADS)

    2002-10-01

    wavebands between 1.6 and 3.5 µm. The compact objects are stars and their colours indicate their temperature (blue = "hot", red = "cool"). There is also diffuse infrared emission from interstellar dust between the stars. The two yellow arrows mark the position of the black hole candidate "SgrA*" at the very centre of the Milky Way galaxy. The scale is indicated; the 1 light-year bar subtends an angle of 8 arcsec in the sky. The centre of our Milky Way galaxy is located in the southern constallation Sagittarius (The Archer) and is "only" 26,000 light-years away [5]. On high-resolution images, it is possible to discern thousands of individual stars within the central, one light-year wide region (this corresponds to about one-quarter of the distance to "Proxima Centauri", the star nearest to the solar system). Using the motions of these stars to probe the gravitational field, observations with the 3.5-m New Technology Telescope (NTT) at the ESO La Silla Observatory (Chile) (and subsequently at the 10-m Keck telescope , Hawaii, USA) over the last decade have shown that a mass of about 3 million times that of the Sun is concentrated within a radius of only 10 light-days [5] of the compact radio and X-ray source SgrA* ("Sagittarius A") at the center of the star cluster. This means that SgrA* is the most likely counterpart of the putative black hole and, at the same time, it makes the Galactic Center the best piece of evidence for the existence of such supermassive black holes . However, those earlier investigations could not exclude several other, non-black hole configurations. "We then needed even sharper images to settle the issue of whether any configuration other than a black hole is possible and we counted on the ESO VLT telescope to provide those" , explains Reinhard Genzel , Director at the Max-Planck Institute for Extraterrestrial Physics (MPE) in Garching near Munich (Germany) and member of the present team. "The new NAOS-CONICA (NACO) instrument, built in a close

  8. What Black Business Leaders Can Do for the Black Community.

    ERIC Educational Resources Information Center

    Johnson, John H.

    1985-01-01

    The existence of viable Black businesses is a statement of productivity and hope for the Black community. Black business leaders can help Black America by giving, soliciting, and lending money; by setting examples; by advocating for Black economic progress and change; and by providing opportunities for Black youth. (GC)

  9. NASA Now: Black Holes

    NASA Video Gallery

    In this NASA Now episode, Dr. Daniel Patnaude talks about how his team discovered a baby black hole, why this is important and how black holes create tidal forces. Throughout his discussion, Patnau...

  10. Black widow spider (image)

    MedlinePlus

    ... the southern areas of the United States. The black widow makes her home in wood piles, under eaves, and other undisturbed places. The bite of a black widow can be serious and require medical attention. ...

  11. The Black Studies Boondoggle

    ERIC Educational Resources Information Center

    Long, Richard A.

    1970-01-01

    Indicates tendencies dangerous to the basic purpose of Black Studies, and identifies four external challeges--imperialism, paternalism, nihilism, and materialism. An internal challenge is considered to be the use of European and Establishment constructs to analyze black reality. (DM)

  12. Black and white psychiatrists: therapy with blacks.

    PubMed

    Jones, B E; Gray, B A

    1985-01-01

    This paper is one of a series of reports on the findings of a survey on psychotherapy with nonpsychotic black patients and black and white psychiatrists. The responses of the two groups of psychiatrists are presented and analyzed, focusing on their clinical experiences with their black patients. The differences between the two groups of psychiatrists on the presenting problems, unconscious conflicts, and role of racism with their black patients are among the clinical areas examined and discussed.The psychiatrists treated similar types of black male and female patients; however, the survey results indicate that a large proportion of white psychiatrists have little or no experience treating blacks. Although there were more similarities than differences in responses of black and white psychiatrists to clinical questions, there were differences in the frequency and order in which problems were rated. For example, both groups of psychiatrists rated developing new coping mechanisms as the most frequent problem in stages of the treatment process for both sexes. However, white psychiatrists rated a majority of the problems in stages of the treatment process as occurring more frequently than did black psychiatrists. The findings substantiate difficulties with clinical treatment by a therapist who has a racial, ethnic, or cultural background different from that of his patient.

  13. Black Hole Boldly Goes Where No Black Hole Has Gone Before

    NASA Astrophysics Data System (ADS)

    2007-01-01

    contains millions of these black holes. Black holes are, by definition, invisible. But the region around them can flare up periodically when the black hole feeds. As gas falls into a black hole, it will heat to high temperatures and radiate brightly, particularly in X-rays. Maccarone's team found one such stellar-mass black hole by chance feeding in a globular cluster in a galaxy named NGC 4472, about fifty million light-years away in the Virgo Cluster. XMM-Newton is extremely sensitive to variable X-ray sources and can efficiently search across large patches of the sky. The team also used NASA's Chandra X-ray Observatory, which has superb angular resolution to pinpoint the X-ray source's location. This allowed them to match up the position of the X-ray source with optical images to prove that the black hole was indeed in a globular cluster. Globular clusters are some of the oldest structures in the universe, containing stars over 12 thousand million years old. Black holes in a cluster would likely have formed many thousand millions of years ago, which is why astronomers have assumed they would have been kicked out a long time ago. Details in the X-ray light detected by XMM-Newton leave little doubt that this is a black hole - the object is too bright, and varies by too much to be anything else. In fact, the source is 'extra bright', - an Ultraluminous X-ray object, or ULX. ULXs are brighter than the 'Eddington limit' for stellar mass black holes, the brightness level at which the outward force from X-rays is expected balance the powerful gravitational forces from the black hole. Thus it is often suggested that the ULXs might be intermediate mass black holes - black holes of thousands of solar masses, heavier than the 10-solar-mass stellar black holes, and lighter than the million to thousand million solar mass black holes in quasars. These black holes might then be the missing links between the black holes formed in the death throes of massive stars and the ones in the

  14. Black holes without firewalls

    NASA Astrophysics Data System (ADS)

    Larjo, Klaus; Lowe, David A.; Thorlacius, Larus

    2013-05-01

    The postulates of black hole complementarity do not imply a firewall for infalling observers at a black hole horizon. The dynamics of the stretched horizon, that scrambles and reemits information, determines whether infalling observers experience anything out of the ordinary when entering a large black hole. In particular, there is no firewall if the stretched horizon degrees of freedom retain information for a time of the order of the black hole scrambling time.

  15. Accelerating black diholes and static black dirings

    SciTech Connect

    Teo, Edward

    2006-01-15

    We show how a recently discovered black-ring solution with a rotating 2-sphere can be turned into two new solutions of Einstein-Maxwell-dilaton theory. The first is a four-dimensional solution describing a pair of oppositely charged, extremal black holes--known as a black dihole--undergoing uniform acceleration. The second is a five-dimensional solution describing a pair of concentric, static extremal black rings carrying opposite dipole charges--a so-called black diring. The properties of both solutions, which turn out to be formally very similar, are analyzed in detail. We also present, in an appendix, an accelerating version of the Zipoy-Voorhees solution in four-dimensional Einstein gravity.

  16. Accretion of Ghost Condensate by Black Holes

    SciTech Connect

    Frolov, A

    2004-06-02

    The intent of this letter is to point out that the accretion of a ghost condensate by black holes could be extremely efficient. We analyze steady-state spherically symmetric flows of the ghost fluid in the gravitational field of a Schwarzschild black hole and calculate the accretion rate. Unlike minimally coupled scalar field or quintessence, the accretion rate is set not by the cosmological energy density of the field, but by the energy scale of the ghost condensate theory. If hydrodynamical flow is established, it could be as high as tenth of a solar mass per second for 10MeV-scale ghost condensate accreting onto a stellar-sized black hole, which puts serious constraints on the parameters of the ghost condensate model.

  17. Marketing for Black Alums.

    ERIC Educational Resources Information Center

    Harris, Tracy A.

    1994-01-01

    Considers need for colleges and universities to develop effective marketing plan for recruitment of black students. Highlights advantages of designing marketing plan for recruitment of black alumni to assist in recruitment and retention of black students. Identifies key indicators that often hinder institutions in their recruitment of black…

  18. The Nearest Black Hole

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald (Technical Monitor); Garcia, Michael

    2005-01-01

    The goal of this program is to study black holes, both in our Galaxy and in nearby galaxies. We aim to study both 'stellar mass' x-ray binaries containing black holes (both in our Galaxy and in nearby galaxies), and super-massive black holes in nearby galaxies.

  19. The Non-Black Teacher, Black Literature, and Black Students

    ERIC Educational Resources Information Center

    Shepard, Ray Anthony

    1970-01-01

    Criticizes Keneth Kinnamon's advice in his article Afro-American Literature, the Black Revolution, and Ghetto High Schools," English Journal," vol. 5., no. 2 (February 1970), pp. 189-94 (see TE 200 536). (SW)

  20. The black tide model of QSOs

    NASA Technical Reports Server (NTRS)

    Young, P. J.; Shields, G. A.; Wheeler, J. C.

    1977-01-01

    The paper develops certain aspects of a model wherein a QSO is a massive black hole located in a dense galactic nucleus, with its growth and luminosity fueled by tidal disruption of passing stars. Cross sections for tidal disruptions are calculated, taking into account the thermal energy of stars, relativistic effects, and partial disruption removing only the outer layers of a star. Accretion rates are computed for a realistic distribution of stellar masses and evolutionary phases, the effect of the black hole on the cluster distribution is examined, and the red-giant disruption rate is evaluated for hole mass of at least 300 million solar masses, the cutoff of disruption of main-sequence stars. The results show that this black-tide model can explain QSO luminosities of at least 1 trillion suns if the black hole remains almost maximally Kerr as it grows above 100 million solar masses and if 'loss-cone' depletion of the number of stars in disruptive orbits is unimportant.

  1. Observational Signatures of High-Redshift Quasars and Local Relics of Black Hole Seeds

    NASA Astrophysics Data System (ADS)

    Reines, Amy E.; Comastri, Andrea

    2016-10-01

    Observational constraints on the birth and early evolution of massive black holes come from two extreme regimes. At high redshift, quasars signal the rapid growth of billion-solar-mass black holes and indicate that these objects began remarkably heavy and/or accreted mass at rates above the Eddington limit. At low redshift, the smallest nuclear black holes known are found in dwarf galaxies and provide the most concrete limits on the mass of black hole seeds. Here, we review current observational work in these fields that together are critical for our understanding of the origin of massive black holes in the Universe.

  2. Searching for Intermediate Mass Black Holes with Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Sadeghian, Laleh; Wade, Leslie

    2016-03-01

    Intermediate Mass Black Holes (IMBHs) are conjectured to occupy the mass space between stellar-mass and super-massive black holes, roughly between 100 and 105 solar masses. The coalescence and merger of IMBH binaries with masses of a few hundred solar masses is an intriguing possible source of gravitational waves for Advanced LIGO and Advanced Virgo. A single detection of an IMBH binary merger would provide the first unambiguous proof of IMBH existence. Searches for these sources have started on data collected by the Advanced LIGO since September 2015. In this talk I will present a search method for these sources in the advanced detector era, based on known signal morphology.

  3. Magnetized static black Saturn

    SciTech Connect

    Yazadjiev, Stoytcho S.

    2008-06-15

    We present a new static solution to the 5D Einstein-Maxwell equations describing a static black hole surrounded by a nonrotating dipole black ring. The configuration is kept in equilibrium by an external magnetic field interacting with the dipole charge of the black ring. The properties of the black Saturn-like configuration are studied and the basic physical quantities are calculated. The solution demonstrates 2-fold continuous nonuniqueness of the 5D magnetized static neutral black objects for fixed total mass and Melvin background.

  4. Black Hole Battery

    NASA Astrophysics Data System (ADS)

    Levin, Janna; D'Orazio, Daniel

    2016-03-01

    Black holes are dark dead stars. Neutron stars are giant magnets. As the neutron star orbits the black hole, an electronic circuit forms that generates a blast of power just before the black hole absorbs the neutron star whole. The black hole battery conceivably would be observable at cosmological distances. Possible channels for luminosity include synchro-curvature radiation, a blazing fireball, or even an unstable, short-lived black hole pulsar. As suggested by Mingarelli, Levin, and Lazio, some fraction of the battery power could also be reprocessed into coherent radio emission to populate a subclass of fast radio bursts.

  5. Searching for Black Holes

    NASA Technical Reports Server (NTRS)

    Garica, M.

    2001-01-01

    In 1995 we proposed to carry out ground-based observations in order to securely identify stellar mass black holes in our galaxy. This type 4 proposal under NASA's UV, Visible, and Gravitational Astrophysics program compliments NASA's space-based research by following up black hole candidates found and studied with space-based observatories, in order to determine if they are indeed black holes. While our primary goal is to securely identify black holes by measuring their masses, a secondary goal is identifying unique visible-range signatures for black holes.

  6. Nonstationary analogue black holes

    NASA Astrophysics Data System (ADS)

    Eskin, Gregory

    2014-12-01

    We study the existence of analogue nonstationary spherically symmetric black holes. The prime example is the acoustic model see Unruh (1981 Phys. Rev. Lett. 46 1351). We consider also a more general class of metrics that could be useful in other physical models of analogue black and white holes. We give examples of the appearance of black holes and of disappearance of white holes. We also discuss the relation between the apparent and the event horizons for the case of analogue black holes. In the end we study the inverse problem of determination of black or white holes by boundary measurements for the spherically symmetric nonstationary metrics.

  7. Fine pitch grids for an x-ray solar imaging spectrometer fabricated by optical lithography and XeF2 etching

    NASA Astrophysics Data System (ADS)

    Brennen, Reid A.; Hecht, Michael H.; Wiberg, Dean V.; Manion, Steven; Bonivert, William D.; Hruby, Jill M.; Pister, Kristofer S. J.; Kruglick, Ezekiel J.

    1995-09-01

    We have developed fine pitch, sub-collimating X-ray grids for an instrument in the High Energy Solar Spectroscopic Imager (HESSI), a proposed NASA mission. In addition to high- energy X-rays, the instrument requires collimation of photons with energies of less than 4 keV such that free-standing grids are required that have no material between the grid slats. We have fabricated 25 micrometer thick gold grids that can collimate photons from visible light up to 30 keV X-rays. They are 55 millimeters in diameter and have 200 micrometer thick silicon support structures. The fabrication process starts with 200 micrometer thick 3 inch wafers onto which a 50 angstrom chrome, 300 angstrom gold electroplating strike is e-beam evaporated. A 25 micrometer thick optical resist is deposited on the wafers using a low spin rate. The resist is exposed and developed and an oxygen plasma clean is performed to fully strip resist residue from the strike. 25 micrometers of gold is then plated in the resist mold, resulting in a gold grid with photoresist between each gold slat. The wafer is turned over and a 50 micrometer dry resist is patterned such that it has a array of 1 by 4 millimeter openings to the silicon. The silicon is etched through to the chrome/gold strike using a xenon difluoride etching process. Both types of photoresist are removed with acetone followed by a piranha clean and the chrome/gold strike is removed with a hydrochloric acid and hydrogen peroxide chrome etch which also slowly etches gold.

  8. IMAGES OF BLACK AMERICANS

    PubMed Central

    Fiske, Susan T.; Bergsieker, Hilary B.; Russell, Ann Marie; Williams, Lyle

    2013-01-01

    Images of Black Americans are becoming remarkably diverse, enabling Barack Obama to defy simple-minded stereotypes and succeed. Understood through the Stereotype Content Model’s demonstrably fundamental trait dimensions of perceived warmth and competence, images of Black Americans show three relevant patterns. Stereotyping by omission allows non-Blacks to accentuate the positive, excluding any lingering negativity but implying it by its absence; specifically, describing Black Americans as gregarious and passionate suggests warmth but ignores competence and implies its lack. Obama’s credentials prevented him from being cast as incompetent, though the experience debate continued. His legendary calm and passionate charisma saved him on the warmth dimension. Social class subtypes for Black Americans differentiate dramatically between low-income Blacks and Black professionals, among both non-Black and Black samples. Obama clearly fit the moderately warm, highly competent Black-professional subtype. Finally, the campaign’s events (and nonevents) allowed voter habituation to overcome non-Blacks’ automatic emotional vigilance to Black Americans. PMID:24235974

  9. Thermal to electrical energy converter based on black Si

    NASA Astrophysics Data System (ADS)

    Nishijima, Y.; Balčytis, A.; Komatsu, R.; Yamamura, T.; Seniutinas, G.; Wong, B. T.; Juodkazis, S.

    2015-03-01

    Photo-thermal - to - electrical converter is demonstrated by using a commercial Peltier Bi-Te element with a hot contact made out of nanotextured Si (black-Si). Black-Si with colloidal Au nanoparticles is shown to further increase the efficiency of thermal-to-electrical conversion. Peculiarities of heat harvesting using black-Si with plasmonic Au nanoparticles at different gold densities are analyzed. Solar radiation absorption and electric field enhancement in plain and Au nanoparticle decorated black-Si was simulated using finite difference time domain (FDTD) method. Thermal conduction in nanotextured black-Si was explained using phonon Monte-Carlo simulations at the nanoscale. Strategies for creating larger thermal gradient on Peltier element using nanotextured light absorbers is discussed.

  10. Songlines from Direct Collapse Seed Black Holes

    NASA Astrophysics Data System (ADS)

    Aykutalp, Aycin; Wise, John; Spaans, Marco; Meijerink, Rowin

    2015-01-01

    In the last decade, the growth of supermassive black holes (SMBHs) has been intricately linked to galaxy formation and evolution, and is a key ingredient in the assembly of galaxies. Observations of SMBHs with masses of 109 solar at high redshifts (z~7) poses challenges to the theory of seed black hole formation and their growth in young galaxies. Fundamental to understanding their existence within the first billion years after the Big Bang, is the identification of their formation processes, growth rate and evolution through cosmic time. We perform cosmological hydrodynamic simulations following the growth of direct collapse seed black holes (DCBH) including X-ray irradiation from the central black hole, stellar feedback both from metal-free and metal-rich stars and H2 self-shielding. These simulations demonstrate that X-ray irradiation from the central black hole regulates its growth and influence the formation of stellar population in the host halo. In particular, X-ray radiation enhances H2 formation in metal-free gas and initially induces the star formation in the halo. However, in the long term, X-ray irradiation from the accreting seed DCBH stifles the initial growth relative to the Eddington rate argument. This further complicates the explanation for the existence of SMBHs in the early universe.

  11. Black hole based tests of general relativity

    NASA Astrophysics Data System (ADS)

    Yagi, Kent; Stein, Leo C.

    2016-03-01

    General relativity has passed all solar system experiments and neutron star based tests, such as binary pulsar observations, with flying colors. A more exotic arena for testing general relativity is in systems that contain one or more black holes. Black holes are the most compact objects in the Universe, providing probes of the strongest-possible gravitational fields. We are motivated to study strong-field gravity since many theories give large deviations from general relativity only at large field strengths, while recovering the weak-field behavior. In this article, we review how one can probe general relativity and various alternative theories of gravity by using electromagnetic waves from a black hole with an accretion disk, and gravitational waves from black hole binaries. We first review model-independent ways of testing gravity with electromagnetic/gravitational waves from a black hole system. We then focus on selected examples of theories that extend general relativity in rather simple ways. Some important characteristics of general relativity include (but are not limited to) (i) only tensor gravitational degrees of freedom, (ii) the graviton is massless, (iii) no quadratic or higher curvatures in the action, and (iv) the theory is four-dimensional. Altering a characteristic leads to a different extension of general relativity: (i) scalar-tensor theories, (ii) massive gravity theories, (iii) quadratic gravity, and (iv) theories with large extra dimensions. Within each theory, we describe black hole solutions, their properties, and current and projected constraints on each theory using black hole based tests of gravity. We close this review by listing some of the open problems in model-independent tests and within each specific theory.

  12. Solar Energy.

    ERIC Educational Resources Information Center

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  13. Solar energy

    NASA Technical Reports Server (NTRS)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  14. Solar energy

    NASA Astrophysics Data System (ADS)

    Rapp, D.

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  15. Solar Systems

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The solar collectors shown are elements of domestic solar hot water systems produced by Solar One Ltd., Virginia Beach, Virginia. Design of these systems benefited from technical expertise provided Solar One by NASA's Langley Research Center. The company obtained a NASA technical support package describing the d e sign and operation of solar heating equipment in NASA's Tech House, a demonstration project in which aerospace and commercial building technology are combined in an energy- efficient home. Solar One received further assistance through personal contact with Langley solar experts. The company reports that the technical information provided by NASA influenced Solar One's panel design, its selection of a long-life panel coating which increases solar collection efficiency, and the method adopted for protecting solar collectors from freezing conditions.

  16. Effects of Chrome Contamination on the Performance of La0.6Sr0.4Co0.2Fe0.8O­3 Cathode Used in Solid Oxide Fuel Cells

    SciTech Connect

    Kim, Jin Yong Y.; Sprenkle, Vince L.; Canfield, Nathan L.; Meinhardt, Kerry D.; Chick, Lawrence A.

    2006-04-01

    Chrome poisoning effects of various Cr-containing metal sources on the electrochemical performance of the La0.6Sr0.4Co0.2Fe0.8O­3 (LSCF6428) cathode have been investigated. It was found that chromia-forming metals caused significant fade in power density due to the chrome poisoning, while alumina-forming alloys exhibited no influence on the cell degradation. This degradation caused by the chrome poisoning was accelerated at higher operating temperatures. Microstructural analysis conducted on the cells tested with chromia-formers exhibited the formation of a strontium chromate phase in the entire cathode, leading to the homogeneous distribution of Cr in the cathode. Although the Mn-containing chromia former such as Crofer22 formed a continuous layer of the Cr-Mn oxide scale on the mesh surface, it was not effective enough to prevent Cr poisoning of the cathode. In contrast, alumina-formers such as Haynes214 and Kanthal formed a continuous layer of the alumina scale, resulting in no Cr contamination in the LSCF cathode.

  17. Quantization of Black Holes

    NASA Astrophysics Data System (ADS)

    He, Xiao-Gang; Ma, Bo-Qiang

    We show that black holes can be quantized in an intuitive and elegant way with results in agreement with conventional knowledge of black holes by using Bohr's idea of quantizing the motion of an electron inside the atom in quantum mechanics. We find that properties of black holes can also be derived from an ansatz of quantized entropy Δ S = 4π k Δ R/{{-{λ }}}, which was suggested in a previous work to unify the black hole entropy formula and Verlinde's conjecture to explain gravity as an entropic force. Such an Ansatz also explains gravity as an entropic force from quantum effect. This suggests a way to unify gravity with quantum theory. Several interesting and surprising results of black holes are given from which we predict the existence of primordial black holes ranging from Planck scale both in size and energy to big ones in size but with low energy behaviors.

  18. Advanced Solar Power Systems

    NASA Technical Reports Server (NTRS)

    Atkinson, J. H.; Hobgood, J. M.

    1984-01-01

    The Advanced Solar Power System (ASPS) concentrator uses a technically sophisticated design and extensive tooling to produce very efficient (80 to 90%) and versatile energy supply equipment which is inexpensive to manufacture and requires little maintenance. The advanced optical design has two 10th order, generalized aspheric surfaces in a Cassegrainian configuration which gives outstanding performance and is relatively insensitive to temperature changes and wind loading. Manufacturing tolerances also have been achieved. The key to the ASPS is the direct absorption of concentrated sunlight in the working fluid by radiative transfers in a black body cavity. The basic ASPS design concepts, efficiency, optical system, and tracking and focusing controls are described.

  19. Black branes as piezoelectrics.

    PubMed

    Armas, Jay; Gath, Jakob; Obers, Niels A

    2012-12-14

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

  20. Naked black holes

    SciTech Connect

    Horowitz, G.T.; Ross, S.F.

    1997-08-01

    It is shown that there are large static black holes for which all curvature invariants are small near the event horizon, yet any object which falls in experiences enormous tidal forces {ital outside} the horizon. These black holes are charged and near extremality, and exist in a wide class of theories including string theory. The implications for cosmic censorship and the black hole information puzzle are discussed. {copyright} {ital 1997} {ital The American Physical Society}

  1. Black branes as piezoelectrics.

    PubMed

    Armas, Jay; Gath, Jakob; Obers, Niels A

    2012-12-14

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six. PMID:23368298

  2. What Black Educators are Saying.

    ERIC Educational Resources Information Center

    Wright, Nathan, Jr., Ed.

    Contents of this book are comprised of five groups of articles: Part I. The Black Educator: "Education for black humanism; a way of approaching it," Preston Wilcox; "The new black dimension in our society," Olivia Pearl Stokes; "The black teacher and black Power," Leslie Campbell; and, "The difference," Leslie Campbell. Part II. The White…

  3. Stability of Black Holes and Black Branes

    NASA Astrophysics Data System (ADS)

    Hollands, Stefan; Wald, Robert M.

    2013-08-01

    We establish a new criterion for the dynamical stability of black holes in D ≥ 4 spacetime dimensions in general relativity with respect to axisymmetric perturbations: Dynamical stability is equivalent to the positivity of the canonical energy, {{E}}, on a subspace, {{T}}, of linearized solutions that have vanishing linearized ADM mass, momentum, and angular momentum at infinity and satisfy certain gauge conditions at the horizon. This is shown by proving that—apart from pure gauge perturbations and perturbations towards other stationary black holes—{{E}} is nondegenerate on {{T}} and that, for axisymmetric perturbations, {{E}} has positive flux properties at both infinity and the horizon. We further show that {{E}} is related to the second order variations of mass, angular momentum, and horizon area by {{E} = δ^2 M -sum_A Ω_A δ^2 J_A - κ/8πδ^2 A}, thereby establishing a close connection between dynamical stability and thermodynamic stability. Thermodynamic instability of a family of black holes need not imply dynamical instability because the perturbations towards other members of the family will not, in general, have vanishing linearized ADM mass and/or angular momentum. However, we prove that for any black brane corresponding to a thermodynamically unstable black hole, sufficiently long wavelength perturbations can be found with {{E} < 0} and vanishing linearized ADM quantities. Thus, all black branes corresponding to thermodynmically unstable black holes are dynamically unstable, as conjectured by Gubser and Mitra. We also prove that positivity of {{E}} on {{T}} is equivalent to the satisfaction of a " local Penrose inequality," thus showing that satisfaction of this local Penrose inequality is necessary and sufficient for dynamical stability. Although we restrict our considerations in this paper to vacuum general relativity, most of the results of this paper are derived using general Lagrangian and Hamiltonian methods and therefore can be

  4. Black nightshade poisoning

    MedlinePlus

    Nightshade poisoning; Morelle noire poisoning; Wonderberry poisoning ... Black nightshade poisoning can affect many areas of the body. EYES, EARS, NOSE, MOUTH, AND THROAT Dry mouth Enlarged (dilated) pupils ...

  5. Black stain - a review.

    PubMed

    Ronay, Valerie; Attin, Thomas

    2011-01-01

    The purpose of this review was to summarise the fundamentals about black stain, its diagnosis and possible differential diagnoses as well as its microbiology and therapy. In addition, various studies investigating the relationship between black stain and dental caries are examined. Many studies report lower caries prevalence in children with black stain, but this finding could not be confirmed by all authors. Also, a negative relation between degree of staining and caries severity has been described. Reasons for these results are not yet clear but it was speculated that they are related to the specific oral microflora described in black stain-affected individuals. PMID:21594205

  6. Wear and migration of highly cross-linked and conventional cemented polyethylene cups with cobalt chrome or Oxinium femoral heads: a randomized radiostereometric study of 150 patients.

    PubMed

    Kadar, Thomas; Hallan, Geir; Aamodt, Arild; Indrekvam, Kari; Badawy, Mona; Skredderstuen, Arne; Havelin, Leif Ivar; Stokke, Terje; Haugan, Kristin; Espehaug, Birgitte; Furnes, Ove

    2011-08-01

    This randomized study was performed to compare wear and migration of five different cemented total hip joint articulations in 150 patients. The patients received either a Charnley femoral stem with a 22.2 mm head or a Spectron EF femoral stem with a 28 mm head. The Charnley articulated with a γ-sterilized Charnley Ogee acetabular cup. The Spectron EF was used with either EtO-sterilized non-cross-linked polyethylene (Reflection All-Poly) or highly cross-linked (Reflection All-Poly XLPE) cups, combined with either cobalt chrome (CoCr) or Oxinium femoral heads. The patients were followed with repeated RSA measurements for 2 years. After 2 years, the EtO-sterilized non-cross-linked Reflection All-Poly cups had more than four times higher proximal penetration than its highly cross-linked counterpart. Use of Oxinium femoral heads did not affect penetration at 2 years compared to heads made of CoCr. Further follow-up is needed to evaluate the benefits, if any, of Oxinium femoral heads in the clinical setting. The Charnley Ogee was not outperformed by the more recently introduced implants in our study. We conclude that this prostheses still represents a standard against which new implants can be measured.

  7. A novel electrochemical sensor for the analysis of β-agonists: the poly(acid chrome blue K)/graphene oxide-nafion/glassy carbon electrode.

    PubMed

    Lin, Xiaoyun; Ni, Yongnian; Kokot, Serge

    2013-09-15

    A novel modified electrode was constructed by the electro-polymerization of 4,5-dihydroxy-3-[(2-hydroxy-5-sulfophenyl)azo]-2,7-naphthalenedisulfonic acid trisodium salt (acid chrome blue K (ACBK)) at a graphene oxide (GO)-nafion modified glassy carbon electrode (GCE). The characterization of an electrochemically synthesized poly-ACBK/GO-nafion film was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques, and the results were interpreted and compared at each stage of the electrode construction. Electrochemical oxidation of eight β-agonists - clenbuterol, salbutamol, terbutaline, ractopamine, dopamine, dobutamine, adrenaline, and isoprenaline, was investigated by CV at the different electrodes. At the poly-ACBK/GO-nafion/GCE, the linear sweep voltammetry peak currents of the eight β-agonists increased linearly with their concentrations in the range of 1.0-36.0 ng mL(-1), respectively, and their corresponding limits of detection (LODs) were within the 0.58-1.46 ng mL(-1) range. This electrode showed satisfactory reproducibility and stability, and was used successfully for the quantitative analysis of clenbuterol in pork samples.

  8. Tribological evaluation of PS300: A new chrome oxide based solid lubricant coating sliding against Al2O3 From 25 to 650 C

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Laskowski, J. A.

    1996-01-01

    This paper presents the tribological characteristics of Al203 sliding against PS300; a chrome oxide based self lubricating coating. Al203 pins were slid against PS300 coated superalloy disks in air, under a 4.9 N load at velocities of 1 to 8 m/s. At a sliding velocity of 1 m/s, friction ranged from 0.6 at 25 C to 0.2 at 650 C. Wear factors for the Al203 pins were in the 10(exp -7) mm(exp 3)/N-m range and for the PS300 coating was in the 10(exp -5) mm(exp 3)/N-m range. The test results suggest that increased surface temperature resulting from either frictional heating, generated by increased sliding velocity, or ambient heating caused a reduction in friction and wear of the sliding couple. Based upon these results, the tested material combination is a promising candidate for high temperature wear applications.

  9. Magnetic property variation in carbon steel and chrome-molybdenum steel as a function of uniaxial stress noncoaxial with the magnetic field (abstract)

    SciTech Connect

    Sablik, M.J. ); Kaminski, D.A.; Jiles, D.C.; Biner, S.B. )

    1993-05-15

    Magnescope[sup 1] magnetic measurements were made on carbon steel specimens ranging from 0.1--0.8 wt %C and on chrome-molybdenum steel specimens cut from electric power plant pipes previously in service. The carbon steel specimens were heat-treated using three procedures: (1) spheroidization, (2) quenching, and (3) quench and tempering. The specimens were subjected to uniaxial tension up to 40 ksi. The inspection head was aligned so that the magnetic field was oriented at different angles with respect to the stress axis. Magnetic properties (such as coercivity and maximum differential permeability) were extracted from digitized magnetic hysteresis loop measurements. Magnetic properties were studied as a function of stress at each angle of stress-field orientation. To our knowledge, such a comprehensive study of noncoaxial stress and field effects has never been accomplished before for such a wide variety of steel specimens. Results for the various materials are presented for different orientation angles and compared to numerical results from the noncoaxial magnetomechanical hysteresis model of Sablik [ital et] [ital al].[sup 2

  10. A new critical dimension metrology for chrome-on-glass substrates based on s-parameter measurements extracted from coplanar waveguide test structures

    NASA Astrophysics Data System (ADS)

    Nwokoye, Chidubem A.; Zaghloul, Mona; Cresswell, Michael W.; Allen, Richard A.; Murabito, Christine E.

    2006-10-01

    The technical objective of the work reported here is to assess whether radio-frequency (RF) measurements made on coplanar waveguide (CPW) test structures, which are replicated in conducting material on insulating substrates, could be employed to extract the critical dimension (CD) of the signal line using its center-to-center separation from the groundlines as a reference. The specific near-term objective is to assess whether this CPW-based CD-metrology has sensitivity and repeatability competitive with the other metrology techniques that are now used for chrome-on-glass (COG) photomasks. An affirmative answer is encouraging because advancing to a non-contact and non-vacuum implementation would then seem possible for this application. Our modeling of specific cases shows that, when the pitch of the replicated lines of the CPW is maintained constant, the sensitivity of its characteristic impedance to the CDs of the signal and ground lines is approximately 60 Ω/μm. This is a potentially useful result. For the same implementation, the quantity ∂C/∂w has a value of approximately 45 (pF/m)/μm, which appears to be large enough to provide acceptable accuracy.

  11. The Black Caucus Votes No

    ERIC Educational Resources Information Center

    Urban Review, 1972

    1972-01-01

    From a statement on media practices regarding the dissemination of a wide range of documentary and other programming about the state of Black America without any input, consultation, or decisions by black Americans, issued by the Congressional Black Caucus. (JM)

  12. Solar Collectors

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Solar Energy's solar panels are collectors for a solar energy system which provides heating for a drive-in bank in Akron, OH. Collectors were designed and manufactured by Solar Energy Products, a firm established by three former NASA employees. Company President, Frank Rom, an example of a personnel-type technology transfer, was a Research Director at Lewis Research Center, which conducts extensive solar heating and cooling research, including development and testing of high-efficiency flat-plate collectors. Rom acquired solar energy expertise which helped the company develop two types of collectors, one for use in domestic/commercial heating systems and the other for drying grain.

  13. Massive Black Hole Implicated in Stellar Destruction

    NASA Astrophysics Data System (ADS)

    2010-01-01

    of Alabama who led the study. Irwin and his colleagues obtained optical spectra of the object using the Magellan I and II telescopes in Las Campanas, Chile. These data reveal emission from gas rich in oxygen and nitrogen but no hydrogen, a rare set of signals from globular clusters. The physical conditions deduced from the spectra suggest that the gas is orbiting a black hole of at least 1,000 solar masses. The abundant amount of oxygen and absence of hydrogen indicate that the destroyed star was a white dwarf, the end phase of a solar-type star that has burned its hydrogen leaving a high concentration of oxygen. The nitrogen seen in the optical spectrum remains an enigma. "We think these unusual signatures can be explained by a white dwarf that strayed too close to a black hole and was torn apart by the extreme tidal forces," said coauthor Joel Bregman of the University of Michigan. Theoretical work suggests that the tidal disruption-induced X-ray emission could stay bright for more than a century, but it should fade with time. So far, the team has observed there has been a 35% decline in X-ray emission from 2000 to 2008. The ULX in this study is located in NGC 1399, an elliptical galaxy about 65 million light years from Earth. Irwin presented these results at the 215th meeting of the American Astronomical Society in Washington, DC. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

  14. Integrated solar collector

    DOEpatents

    Tchernev, Dimiter I.

    1985-01-01

    A solar collector having a copper panel in a contiguous space relationship with a condenser-evaporator heat exchanger located under the panel, the panel having a honeycomb-like structure on its interior defining individual cells which are filled with zeolite loaded, in its adsorbed condition, with 18 to 20% by weight of water. The interior of the panel and heat exchanger are maintained at subatmospheric pressure of about 0.1 to 1 psia. The panel and heat exchanger are insulated on their lateral sides and bottoms and on the top of the heat exchange. The panel has a black coating on its top which is exposed to and absorbs solar energy. Surrounding the insulation (which supports the panel) is an extruded aluminum framework which supports a pair of spaced-apart glass panels above the solar panel. Water in conduits from a system for heating or cooling or both is connected to flow into an inlet and discharge from outlet of a finned coil received within the heat exchanger. The collector panel provides heat during the day through desorption and condensing of water vapor from the heated solar panel in the heat exchanger and cools at night by the re-adsorption of the water vapor from the heat exchanger which lowers the absolute pressure within the system and cools the heat exchange coils by evaporation.

  15. Black Studies Year One.

    ERIC Educational Resources Information Center

    Long, Richard A.

    Though Dubois tried to begin a series of scientific studies on the Negro problem in America more than 70 years ago, only recently have attempts been made to present a true history of the Black man in institutions of higher learning. Until that time, the experience of the Black man was defined in Euro-American terms, or in most cases was completely…

  16. Black Males Left Behind

    ERIC Educational Resources Information Center

    Mincy, Ronald B., Ed.

    2006-01-01

    Despite the overall economic gains in the 1990s, many young black men continue to have the poorest life chances of anyone in our society. Joblessness and low earnings among these less-educated young adults are contributing to reductions in marriage, increases in nonmarital childbearing, and a host of other social problems. In "Black Males Left…

  17. The Black Woman's Burden

    ERIC Educational Resources Information Center

    Hayes, Dianne

    2012-01-01

    Not even the first lady of the most powerful nation in the world is immune to stereotypes that have plagued Black women since first setting foot on American soil. Stereotypes of being the "angry Black woman" and curiosity about differences in appearance still persist from the academy to 1600 Pennsylvania Ave. As African-American women rise in…

  18. Black English: Two Viewpoints.

    ERIC Educational Resources Information Center

    Kleederman, Frances

    This paper focuses on the two main schools of thought concerning the structure of Black English and its relationship to other dialects. One approach is that of the social dialectologists who claim that Black English shares features and origins of white non-standard Southern speech; the frequency with which specific features occur in actual speech…

  19. Learning Mathematics while Black

    ERIC Educational Resources Information Center

    Martin, Danny Bernard

    2012-01-01

    While research by scholars has contributed greatly to an emerging knowledge base on Black children and mathematics, there continues to be a dire need for insightful research that de-centers longstanding accounts that have contributed to the construction of Black children as mathematically illiterate and as less than ideal learners relative to…

  20. Black Families. Interdisciplinary Perspectives.

    ERIC Educational Resources Information Center

    Cheatham, Harold E., Ed.; Stewart, James B., Ed.

    Since the early 1960s, the black family has been characterized as pathological. This six-part collection of 18 research studies presents alternative approaches to understanding the special characteristics of black families. Part I, "Theoretical and Methodological Perspectives," comprises a comparison of the pioneering work of W. E. B. Du Bois and…

  1. Black Women in Sport.

    ERIC Educational Resources Information Center

    Green, Tina Sloan; And Others

    An overview of the achievements of black women in sports is presented in this collection of essays, biographical sketches, and philosophical investigations. The work is divided into five chapters, the first of which focuses on prejudice (racial and sexual), absence of black women as subjects in the research base, work/home/family pressures, black…

  2. Arbitrators, Blacks and Discipline

    ERIC Educational Resources Information Center

    Jennings, Kenneth

    1975-01-01

    A discussion of the handling of disciplinary problems of black employees concludes that management should be concerned because of the effect that grievance resolution may have on the company's overall employee discipline program and the additional appeal alternatives available to the black employee. (Author/EA)

  3. Black phosphorus gas sensors.

    PubMed

    Abbas, Ahmad N; Liu, Bilu; Chen, Liang; Ma, Yuqiang; Cong, Sen; Aroonyadet, Noppadol; Köpf, Marianne; Nilges, Tom; Zhou, Chongwu

    2015-05-26

    The utilization of black phosphorus and its monolayer (phosphorene) and few-layers in field-effect transistors has attracted a lot of attention to this elemental two-dimensional material. Various studies on optimization of black phosphorus field-effect transistors, PN junctions, photodetectors, and other applications have been demonstrated. Although chemical sensing based on black phosphorus devices was theoretically predicted, there is still no experimental verification of such an important study of this material. In this article, we report on chemical sensing of nitrogen dioxide (NO2) using field-effect transistors based on multilayer black phosphorus. Black phosphorus sensors exhibited increased conduction upon NO2 exposure and excellent sensitivity for detection of NO2 down to 5 ppb. Moreover, when the multilayer black phosphorus field-effect transistor was exposed to NO2 concentrations of 5, 10, 20, and 40 ppb, its relative conduction change followed the Langmuir isotherm for molecules adsorbed on a surface. Additionally, on the basis of an exponential conductance change, the rate constants for adsorption and desorption of NO2 on black phosphorus were extracted for different NO2 concentrations, and they were in the range of 130-840 s. These results shed light on important electronic and sensing characteristics of black phosphorus, which can be utilized in future studies and applications.

  4. Black Craftsmen Through History.

    ERIC Educational Resources Information Center

    Myers, Robin

    This report traces the evolution of the black craftsmen from ancient Egypt to the present. Special attention is given to the restricted use of black craftsmen under slavery, and the added problems they faced after being freed. Business and union discimination is described, along with recent government and private efforts to achieve equal…

  5. They Made Black History.

    ERIC Educational Resources Information Center

    Elward, Thomas J.

    1981-01-01

    Reviews the history of Black music education in the public schools of Washington, D.C., from 1869 through the 1920s. Appended (on pp38-39) are historical notes on Black composers James Weldon Johnson and John Rosamond Johnson, and their song "Lift Ev'ry Voice and Sing." (Author/SJL)

  6. Grumblings from an Awakening Black Hole

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-11-01

    In June of this year, after nearly three decades of sleep, the black hole V404 Cygni woke up and began grumbling. Scientists across the globe scrambled to observe the sudden flaring activity coming from this previously peaceful black hole. And now were getting the first descriptions of what weve learned from V404 Cygs awakening!Sudden OutburstV404 Cyg is a black hole of roughly nine solar masses, and its in a binary system with a low-mass star. The black hole pulls a stream of gas from the star, which then spirals in around the black hole, forming an accretion disk. Sometimes the material simply accumulates in the disk but every two or three decades, the build-up of gas suddenly rushes toward the black hole as if a dam were bursting.The sudden accretion in these events causes outbursts of activity from the black hole, its flaring easily visible to us. The last time V404 Cyg exhibited such activity was in 1989, and its been rather quiet since then. Our telescopes are of course much more powerful and sensitive now, nearly three decades later so when the black hole woke up and began flaring in June, scientists were delighted at the chance to observe it.The high variability of V404 Cyg is evident in this example set of spectra, where time increases from the bottom panel to the top. [King et al. 2015]Led by Ashley King (Einstein Fellow at Stanford University), a team of scientists observed V404 Cyg with the Chandra X-ray Observatory, obtaining spectra of the black hole during its outbursts. The black hole flared so brightly during its activity that the team had to take precautions to protect the CCDs in their detector from radiation damage! Now the group has released the first results from their analysis.Windy DiskThe primary surprise from V404 Cyg is its winds. Many stellar-mass black holes have outflows of mass, either in the form of directed jets emitted from their centers, or in the form of high-energy winds isotropically emitted from their accretion disks. But V404

  7. Contact dermatitis in blacks.

    PubMed

    Berardesca, E; Maibach, H I

    1988-07-01

    Black skin is characterized by structural and functional differences such as increased stratum corneum cohesion, melanin content, and stratum corneum layers. These differences seem to make black skin difficult for irritants and light to penetrate, thus explaining the common opinion that skin in blacks is harder and develops contact dermatitis less frequently. The paucity of interpretable epidemiologic data and of clinical and experimental studies does not permit confirmation of this hypothesis, and the few data available are controversial. This article describes the main physiologic differences between black and white barrier function and reviews the literature on irritation, sensitization, and transcutaneous penetration. We found that the data are still too incomplete to generalize on the resistance, or lack thereof, of black skin (versus white skin) to chemical irritation, sensitization, and penetration. PMID:3048818

  8. American Black Duck

    USGS Publications Warehouse

    Longcore, J.R.; Clugston, D.A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    A brief summary of the annual cycle of the American Black duck (Anas rubripes) is presented. The history of the American black duck population is tracked by the Mid-Winter Index (MWI) and related to annual harvest. Previous to effective restrictions in the United States in 1982 and later in Canada, the MWI was declining significantly at about 4% annually. Since restrictions were established the black duck population has stabilized, but to reach the goal of 260,000 wintering black ducks in the Atlantic Flyway continued or even more restrictions will be necessary. If the number of breeding pairs can be increased from current levels the black duck population is expected to increase.

  9. Contact dermatitis in blacks.

    PubMed

    Berardesca, E; Maibach, H I

    1988-07-01

    Black skin is characterized by structural and functional differences such as increased stratum corneum cohesion, melanin content, and stratum corneum layers. These differences seem to make black skin difficult for irritants and light to penetrate, thus explaining the common opinion that skin in blacks is harder and develops contact dermatitis less frequently. The paucity of interpretable epidemiologic data and of clinical and experimental studies does not permit confirmation of this hypothesis, and the few data available are controversial. This article describes the main physiologic differences between black and white barrier function and reviews the literature on irritation, sensitization, and transcutaneous penetration. We found that the data are still too incomplete to generalize on the resistance, or lack thereof, of black skin (versus white skin) to chemical irritation, sensitization, and penetration.

  10. Solar Cooking

    Atmospheric Science Data Center

    2014-09-25

    ... (kWh/m2/day) Amount of electromagnetic energy (solar radiation) incident on the surface of the earth. Also referred to as total or global solar radiation.   Midday insolation (kWh/m2/day) Average ...

  11. Solar Lentigo

    MedlinePlus

    ... hyperpigmented) lesion caused by natural or artificial ultraviolet (UV) light. Solar lentigines may be single or multiple. This ... simplex) because it is caused by exposure to UV light. Solar lentigines are benign, but they do indicate ...

  12. Direct formation of supermassive black holes via multi-scale gas inflows in galaxy mergers.

    PubMed

    Mayer, L; Kazantzidis, S; Escala, A; Callegari, S

    2010-08-26

    Observations of distant quasars indicate that supermassive black holes of billions of solar masses already existed less than a billion years after the Big Bang. Models in which the 'seeds' of such black holes form by the collapse of primordial metal-free stars cannot explain the rapid appearance of these supermassive black holes because gas accretion is not sufficiently efficient. Alternatively, these black holes may form by direct collapse of gas within isolated protogalaxies, but current models require idealized conditions, such as metal-free gas, to prevent cooling and star formation from consuming the gas reservoir. Here we report simulations showing that mergers between massive protogalaxies naturally produce the conditions for direct collapse into a supermassive black hole with no need to suppress cooling and star formation. Merger-driven gas inflows give rise to an unstable, massive nuclear gas disk of a few billion solar masses, which funnels more than 10(8) solar masses of gas to a sub-parsec-scale gas cloud in only 100,000 years. The cloud undergoes gravitational collapse, which eventually leads to the formation of a massive black hole. The black hole can subsequently grow to a billion solar masses on timescales of about 10(8) years by accreting gas from the surrounding disk.

  13. Black holes and beyond

    SciTech Connect

    Mathur, Samir D.

    2012-11-15

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome 'remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a 'fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole. - Highlights: Black-Right-Pointing-Pointer The information paradox is a serious problem. Black-Right-Pointing-Pointer To solve it we need to find 'hair' on black holes. Black-Right-Pointing-Pointer In string theory we find 'hair' by the fuzzball construction. Black-Right-Pointing-Pointer Fuzzballs help to resolve many other issues in gravity.

  14. Nucleosynthesis in the neighborhood of a black hole

    NASA Technical Reports Server (NTRS)

    Chakrabarti, Sandip K.

    1986-01-01

    The preliminary results from simulations of nucleosynthesis inside a thick accretion disk around a black hole are discussed as a function of the accretion rate, the viscosity parameter, and the mass of the black hole. Results for the Bondi accretion case are also presented. Taking the case of a 10-solar mass and a 10 to the 6th-solar mass central Schwarzschild hole, detailed evolution of a representative element of matter as it accretes into the hole is presented in the case when the initial abundance (at the outer edge of the disk) is the same as the solar abundance. It is suggested that such studies may eventually shed light on the composition of the outgoing jets observed in the active galaxies and SS433.

  15. Solar Equipment

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A medical refrigeration and a water pump both powered by solar cells that convert sunlight directly into electricity are among the line of solar powered equipment manufactured by IUS (Independent Utility Systems) for use in areas where conventional power is not available. IUS benefited from NASA technology incorporated in the solar panel design and from assistance provided by Kerr Industrial Applications Center.

  16. Buying Solar.

    ERIC Educational Resources Information Center

    Dawson, Joe

    Presented are guidelines for buying solar systems for the individual consumer. This is intended to help the consumer reduce many of the risks associated with the purchase of solar systems, particularly the risks of fraud and deception. Engineering terms associated with solar technology are presented and described to enable the consumer to discuss…

  17. Evaluation of selective solar-absorber surfaces. Semi-annual report, March 25-September 24, 1981

    SciTech Connect

    Osiecki, R.A.

    1981-10-01

    The goals of the study reported are: to induce the degradation of the optical properties of selected samples of surface finishes by exposing them to a high humidity/high temperature environment for extended periods of time; and to analyze the degraded and non-degraded surface finishes to determine the operative degradation mechanism in each surface finish. The eight surface finishes tested include: black chrome on aluminum, on copper, and on nickel-plated copper; copper oxide/copper on mild steel; nickel-chromium oxide on nickel foil; a chromate conversion coating; and a thickness sensitive, silicone based paint. Values of the spectral reflectance, absorptance, and emittance are presented for degraded samples. Surface analysis is reported complete for some of the samples. (LEW)

  18. Black Literature vs. Black Studies: Three Lynchings.

    ERIC Educational Resources Information Center

    Williams, Melvin G.

    When studying Afro-American literature, even in an English class rather than Black Studies class, both student interest and the topic tend to lead discussion toward sociological, not literary, aspects. However, the teacher should emphasize repeatedly the aesthetic dimensions of an artistic work as well as the various literary forms in which a…

  19. Formation of Supermassive Black Hole Seeds

    NASA Astrophysics Data System (ADS)

    Latif, Muhammad A.; Ferrara, Andrea

    2016-10-01

    The detection of quasars at z > 6 unveils the presence of supermassive black holes of a few billion solar masses. The rapid formation process of these extreme objects remains a fascinating and open issue. Such discovery implies that seed black holes must have formed early on, and grown via either rapid accretion or BH/galaxy mergers. In this theoretical review, we discuss in detail various BH seed formation mechanisms and the physical processes at play during their assembly. We discuss the three most popular BH formation scenarios, involving the (i) core-collapse of massive stars, (ii) dynamical evolution of dense nuclear star clusters, (iii) collapse of a protogalactic metal free gas cloud. This article aims at giving a broad introduction and an overview of the most advanced research in the field.

  20. Untapped Resources: "Styling" in Black Students' Writing for Black Audiences.

    ERIC Educational Resources Information Center

    Redd, Teresa M.

    Two studies compared the impact of black and white audiences on black students' writing style. In the first study, eight students in an all-black intermediate composition class completed one argumentative draft addressed to black opponents and one addressed to white opponents on two different topics. The essays were examined for stylistic features…

  1. The next Black America: Obstacles amidst opportunities for Black families.

    PubMed

    Armah, Tichianaa

    2015-09-01

    In this article, the author offers personal accounts on how she feels about the current Black America and obstacles that people face reaching for opportunities for Black families. Focus relies on the current state of Black America, poverty, schools, academic achievement, raising children in the next Black America and much more. (PsycINFO Database Record

  2. The next Black America: Obstacles amidst opportunities for Black families.

    PubMed

    Armah, Tichianaa

    2015-09-01

    In this article, the author offers personal accounts on how she feels about the current Black America and obstacles that people face reaching for opportunities for Black families. Focus relies on the current state of Black America, poverty, schools, academic achievement, raising children in the next Black America and much more. (PsycINFO Database Record PMID:26460716

  3. Black Studies and Black People in the Future

    ERIC Educational Resources Information Center

    Stewart, James B.

    1976-01-01

    Suggests that the demise of Black Studies would foreshadow the future deterioration of the material conditions of black people, a situation which all elements of the black community want to preclude as a possible future for black people. (Author/AM)

  4. On the Charter Question: Black Marxism and Black Nationalism

    ERIC Educational Resources Information Center

    Stern, Mark; Hussain, Khuram

    2015-01-01

    This article brings two black intellectual traditions to bear on the question of charter schools: black Marxism and black nationalism. The authors examine the theoretical and rhetorical devices used to talk about charters schools by focusing on how notions of "black liberation" are deployed by the charter movement, and to what end. The…

  5. Los Alamos optical-materials reliability, maintainability, and exposure testing program

    SciTech Connect

    Moore, S.W.

    1983-04-01

    Methods and results are presented of exposure testing of developmental or advanced materials, nonselective coatings, selective paints, antireflection-treated glass, and heat mirror glazing for the DOE Active Heating and Cooling Materials testing program. Results of investigations of collectors from a number of solar facilities relative to the durability and degradation of their optical materials are also presented. These include: black chrome durability study; Norton Air Force Base polycarbonate glazing study; Perl-Mac/Miromit black nickel study; and black paint investigations.

  6. ULTRAMASSIVE BLACK HOLE COALESCENCE

    SciTech Connect

    Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter E-mail: k.holley@vanderbilt.edu

    2015-01-10

    Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production.

  7. Solar nutrinos

    NASA Technical Reports Server (NTRS)

    Bahcall, J. N.

    1981-01-01

    The topics covered include: an overview of the subject of solar neutrinos, a brief summary of the theory of stellar evolution, a description of the main sources of solar neutrinos, a brief summary of the results of the Brookhaven C1-37 experiment, an anaysis of the principal solar neutrino experiments, and a discussion of how solar neutrino experiments can be used to detect the collapse of stars in the Galaxy. A description of how the Ga-71 experiment can be used to decide whether the origin of the present discrepancy between theory and observation lies in conventional solar models or conventional physics is presented.

  8. Solar flair.

    PubMed Central

    Manuel, John S

    2003-01-01

    Design innovations and government-sponsored financial incentives are making solar energy increasingly attractive to homeowners and institutional customers such as school districts. In particular, the passive solar design concept of daylighting is gaining favor among educators due to evidence of improved performance by students working in daylit classrooms. Electricity-generating photovoltaic systems are also becoming more popular, especially in states such as California that have high electric rates and frequent power shortages. To help spread the word about solar power, the U.S. Department of Energy staged its first-ever Solar Decathlon in October 2002. This event featured solar-savvy homes designed by 14 college teams. PMID:12573926

  9. Solar flair.

    PubMed

    Manuel, John S

    2003-02-01

    Design innovations and government-sponsored financial incentives are making solar energy increasingly attractive to homeowners and institutional customers such as school districts. In particular, the passive solar design concept of daylighting is gaining favor among educators due to evidence of improved performance by students working in daylit classrooms. Electricity-generating photovoltaic systems are also becoming more popular, especially in states such as California that have high electric rates and frequent power shortages. To help spread the word about solar power, the U.S. Department of Energy staged its first-ever Solar Decathlon in October 2002. This event featured solar-savvy homes designed by 14 college teams.

  10. Solar Optics

    SciTech Connect

    Rozsnyai, B.F.

    2000-10-04

    Solar opacities are presented from the center of the Sun to the photosphere. The temperatures, densities and hydrogen mass fractions are taken from the standard solar model. For the heavy element abundances the Grevesse mixture is used. In the solar interior photoabsorption is dominated by free-free absorption and they compare two sets of opacities based on two different models for the inverse bremsstrahlung. The radiative luminosities calculated from the two sets of opacities are compared with those predicted by previous models of the standard solar model and also with the known luminosity of the Sun. pressures, specific heats and the speed of sound in the solar plasma are also presented.

  11. Solar flair.

    PubMed

    Manuel, John S

    2003-02-01

    Design innovations and government-sponsored financial incentives are making solar energy increasingly attractive to homeowners and institutional customers such as school districts. In particular, the passive solar design concept of daylighting is gaining favor among educators due to evidence of improved performance by students working in daylit classrooms. Electricity-generating photovoltaic systems are also becoming more popular, especially in states such as California that have high electric rates and frequent power shortages. To help spread the word about solar power, the U.S. Department of Energy staged its first-ever Solar Decathlon in October 2002. This event featured solar-savvy homes designed by 14 college teams. PMID:12573926

  12. Design investigation of solar powered lasers for space applications

    NASA Technical Reports Server (NTRS)

    Taussig, R.; Bruzzone, C.; Quimby, D.; Nelson, L.; Christiansen, W.; Neice, S.; Cassady, P.; Pindroh, A.

    1979-01-01

    The feasibility of solar powered lasers for continuous operation in space power transmission was investigated. Laser power transmission in space over distances of 10 to 100 thousand kilometers appears possible. A variety of lasers was considered, including solar-powered GDLs and EDLs, and solar-pumped lasers. An indirect solar-pumped laser was investigated which uses a solar-heated black body cavity to pump the lasant. Efficiencies in the range of 10 to 20 percent are projected for these indirect optically pumped lasers.

  13. Measuring Black Hole Spin

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    1999-09-01

    WE PROPOSE TO CARRY OUT A SYSTEMATIC STUDY OF EMISSION AND ABSORPTION SPECTRAL FEATURES THAT ARE OFTEN SEEN IN X-RAY SPECTRA OF BLACK HOLE BINARIES. THE EXCELLENT SENSITIVITY AND ENERGY RESOLUTION OF THE ACIS/HETG COMBINATION WILL NOT ONLY HELP RESOLVE AMBIGUITIES IN INTERPRETING THESE FEATURES, BUT MAY ALLOW MODELLING OF THE EMISSION LINE PROFILES IN DETAIL. THE PROFILES MAY CONTAIN INFORMATION ON SUCH FUNDAMENTAL PROPERTIES AS THE SPIN OF BLACK HOLES. THEREFORE, THIS STUDY COULD LEAD TO A MEASUREMENT OF BLACK HOLE SPIN FOR SELECTED SOURCES. THE RESULT CAN THEN BE DIRECTLY COMPARED WITH THOSE FROM PREVIOUS STUDIES BASED ON INDEPENDENT METHODS.

  14. Solar Energy: Solar System Economics.

    ERIC Educational Resources Information Center

    Knapp, Henry H., III

    This module on solar system economics is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies.…

  15. Solar Sailing

    NASA Technical Reports Server (NTRS)

    Johnson, Les

    2009-01-01

    Solar sailing is a topic of growing technical and popular interest. Solar sail propulsion will make space exploration more affordable and offer access to destinations within (and beyond) the solar system that are currently beyond our technical reach. The lecture will describe solar sails, how they work, and what they will be used for in the exploration of space. It will include a discussion of current plans for solar sails and how advanced technology, such as nanotechnology, might enhance their performance. Much has been accomplished recently to make solar sail technology very close to becoming an engineering reality and it will soon be used by the world s space agencies in the exploration of the solar system and beyond. The first part of the lecture will summarize state-of-the-art space propulsion systems and technologies. Though these other technologies are the key to any deep space exploration by humans, robots, or both, solar-sail propulsion will make space exploration more affordable and offer access to distant and difficult destinations. The second part of the lecture will describe the fundamentals of space solar sail propulsion and will describe the near-, mid- and far-term missions that might use solar sails as a propulsion system. The third part of the lecture will describe solar sail technology and the construction of current and future sailcraft, including the work of both government and private space organizations.

  16. Possible evolution of supermassive black holes from FRI quasars

    NASA Astrophysics Data System (ADS)

    Kim, Matthew I.; Christian, Damian J.; Garofalo, David; D'Avanzo, Jaclyn

    2016-08-01

    We explore the question of the rapid buildup of black hole mass in the early universe employing a growing black hole mass-based determination of both jet and disc powers predicted in recent theoretical work on black hole accretion and jet formation. Despite simplified, even artificial assumptions about accretion and mergers, we identify an interesting low probability channel for the growth of one billion solar mass black holes within hundreds of millions of years of the big bang without appealing to super Eddington accretion. This result is made more compelling by the recognition of a connection between this channel and an end product involving active galaxies with FRI radio morphology but weaker jet powers in mildly sub-Eddington accretion regimes. While FRI quasars have already been shown to occupy a small region of the available parameter space for black hole feedback in the paradigm, we further suggest that the observational dearth of FRI quasars is also related to their connection to the most massive black hole growth due to both these FRIs high redshifts and relative weakness. Our results also allow us to construct the AGN (active galactic nucleus) luminosity function at high redshift, that agree with recent studies. In short, we produce a connection between the unexplained paucity of a given family of AGNs and the rapid growth of supermassive black holes, two heretofore seemingly unrelated aspects of the physics of AGNs.

  17. Using an Infrared Thermometer for Solar Pyranometry

    ERIC Educational Resources Information Center

    Fiedler, B. H.

    2011-01-01

    The simple hand-held infrared thermometer can be used to measure the temperature of surfaces of different reflectivity exposed to sunlight and wind. From four temperature measurements of black and white panels in windy and wind-sheltered conditions, together with the two wind speed measurements, both the flux of incident solar radiation and the…

  18. Enhancement of Solar Water Pasteurization with Reflectors

    PubMed Central

    Safapour, Negar; Metcalf, Robert H.

    1999-01-01

    A simple and reliable method that could be used in developing countries to pasteurize milk and water with solar energy is described. A cardboard reflector directs sunshine onto a black jar, heating water to pasteurizing temperatures in several hours. A reusable water pasteurization indicator verifies that pasteurization temperatures have been reached. PMID:9925631

  19. Five-year comparison of wear using oxidised zirconium and cobalt-chrome femoral heads in total hip arthroplasty: a multicentre randomised controlled trial.

    PubMed

    Jassim, S S; Patel, S; Wardle, N; Tahmassebi, J; Middleton, R; Shardlow, D L; Stephen, A; Hutchinson, J; Haddad, F S

    2015-07-01

    Oxidised zirconium (OxZi) has been developed as an alternative bearing surface for femoral heads in total hip arthroplasty (THA). This study has investigated polyethylene wear, functional outcomes and complications, comparing OxZi and cobalt-chrome (CoCr) as part of a three-arm, multicentre randomised controlled trial. Patients undergoing THA from four institutions were prospectively randomised into three groups. Group A received a CoCr femoral head and highly cross-linked polyethylene (XLPE) liner; Group B received an OxZi femoral head and XLPE liner; Group C received an OxZi femoral head and ultra-high molecular weight polyethylene (UHMWPE) liner. At five years, 368 patients had no statistically significant differences in short-form-36 (p = 0.176 mental, p = 0.756 physical), Western Ontario and McMaster Universities Osteoarthritis Index (p = 0.847), pain scores (p = 0.458) or complications. The mean rate of linear wear was 0.028 mm/year (standard deviation (SD) 0.010) for Group A, 0.023 mm/year (SD 0.010) for Group B, and 0.09 mm/year (SD 0.045) for Group C. Penetration was significantly higher in the UHMWPE liner group compared with both XLPE liner groups (p < 0.001) but no significant difference was noted between CoCr and OxZi when articulating with XLPE (p = 0.153). In this, the largest randomised study of this bearing surface, it appears that using a XLPE acetabular liner is more important in reducing THA component wear than the choice of femoral head bearing, at mid-term follow-up. There is a non-significant trend towards lower wear, coupling OxZi rather than CoCr with XLPE but long-term analysis is required to see if this observation changes with time and becomes significant. PMID:26130341

  20. Five-year comparison of wear using oxidised zirconium and cobalt-chrome femoral heads in total hip arthroplasty: a multicentre randomised controlled trial.

    PubMed

    Jassim, S S; Patel, S; Wardle, N; Tahmassebi, J; Middleton, R; Shardlow, D L; Stephen, A; Hutchinson, J; Haddad, F S

    2015-07-01

    Oxidised zirconium (OxZi) has been developed as an alternative bearing surface for femoral heads in total hip arthroplasty (THA). This study has investigated polyethylene wear, functional outcomes and complications, comparing OxZi and cobalt-chrome (CoCr) as part of a three-arm, multicentre randomised controlled trial. Patients undergoing THA from four institutions were prospectively randomised into three groups. Group A received a CoCr femoral head and highly cross-linked polyethylene (XLPE) liner; Group B received an OxZi femoral head and XLPE liner; Group C received an OxZi femoral head and ultra-high molecular weight polyethylene (UHMWPE) liner. At five years, 368 patients had no statistically significant differences in short-form-36 (p = 0.176 mental, p = 0.756 physical), Western Ontario and McMaster Universities Osteoarthritis Index (p = 0.847), pain scores (p = 0.458) or complications. The mean rate of linear wear was 0.028 mm/year (standard deviation (SD) 0.010) for Group A, 0.023 mm/year (SD 0.010) for Group B, and 0.09 mm/year (SD 0.045) for Group C. Penetration was significantly higher in the UHMWPE liner group compared with both XLPE liner groups (p < 0.001) but no significant difference was noted between CoCr and OxZi when articulating with XLPE (p = 0.153). In this, the largest randomised study of this bearing surface, it appears that using a XLPE acetabular liner is more important in reducing THA component wear than the choice of femoral head bearing, at mid-term follow-up. There is a non-significant trend towards lower wear, coupling OxZi rather than CoCr with XLPE but long-term analysis is required to see if this observation changes with time and becomes significant.

  1. The Price of "Black Dominance."

    ERIC Educational Resources Information Center

    Hoberman, John

    2000-01-01

    Discusses the harmful effects of stereotyping black males as athletes, noting that over-identification with athletes and the world of physical performance limits black children's development by discouraging academic achievement. Examines the negative influence of mass media focus on black athletes, rappers, and stylized ghetto blackness. Discusses…

  2. Black Managers in White Corporations.

    ERIC Educational Resources Information Center

    Fernandez, John P.

    The study examines the major determinants of the career patterns of black managers in white businesses and the effects of corporations on their black managers' identities and relationships to the black community. Analyzed were occupational mobility theories; white and black managers' career patterns, goals, and related factors; company employment…

  3. Precocious Supermassive Black Holes Challenge Theories

    NASA Astrophysics Data System (ADS)

    2004-11-01

    NASA's Chandra X-ray Observatory has obtained definitive evidence that a distant quasar formed less than a billion years after the Big Bang contains a fully-grown supermassive black hole generating energy at the rate of twenty trillion Suns. The existence of such massive black holes at this early epoch of the Universe challenges theories of the formation of galaxies and supermassive black holes. Astronomers Daniel Schwartz and Shanil Virani of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA observed the quasar, known as SDSSp J1306, which is 12.7 billion light years away. Since the Universe is estimated to be 13.7 billion years old, we see the quasar as it was a billion years after the Big Bang. They found that the distribution of X-rays with energy, or X-ray spectrum, is indistinguishable from that of nearby, older quasars. Likewise, the relative brightness at optical and X-ray wavelengths of SDSSp J1306 was similar to that of the nearby group of quasars. Optical observations suggest that the mass of the black hole is about a billion solar masses. Illustration of Quasar SDSSp J1306 Illustration of Quasar SDSSp J1306 Evidence of another early-epoch supermassive black hole was published previously by a team of scientists from the California Institute of Technology and the United Kingdom using the XMM-Newton X-ray satellite. They observed the quasar SDSSp J1030 at a distance of 12.8 billion light years and found essentially the same result for the X-ray spectrum as the Smithsonian scientists found for SDSSp J1306. Chandra's precise location and spectrum for SDSSp J1306 with nearly the same properties eliminate any lingering uncertainty that precocious supermassive black holes exist. "These two results seem to indicate that the way supermassive black holes produce X-rays has remained essentially the same from a very early date in the Universe," said Schwartz. "This implies that the central black hole engine in a massive galaxy was formed very soon

  4. Introducing the Black Hole

    ERIC Educational Resources Information Center

    Ruffini, Remo; Wheeler, John A.

    1971-01-01

    discusses the cosmology theory of a black hole, a region where an object loses its identity, but mass, charge, and momentum are conserved. Include are three possible formation processes, theorized properties, and three way they might eventually be detected. (DS)

  5. Charging black Saturn?

    NASA Astrophysics Data System (ADS)

    Chng, Brenda; Mann, Robert; Radu, Eugen; Stelea, Cristian

    2008-12-01

    We construct new charged static solutions of the Einstein-Maxwell field equations in five dimensions via a solution generation technique utilizing the symmetries of the reduced Lagrangian. By applying our method on the multi-Reissner-Nordström solution in four dimensions, we generate the multi-Reissner-Nordström solution in five dimensions. We focus on the five-dimensional solution describing a pair of charged black objects with general masses and electric charges. This solution includes the double Reissner-Nordström solution as well as the charged version of the five-dimensional static black Saturn. However, all the black Saturn configurations that we found contain either a conical or naked singularity. We also obtain a non-extremal configuration of charged black strings that reduces in the extremal limit to a Majumdar-Papapetrou like solution in five dimensions.

  6. Tuberculosis in Blacks

    MedlinePlus

    ... the United States is declining, there is decreased awareness of TB signs and symptoms among health care ... working on projects designed to educate and raise awareness about TB in black communities. In one project, ...

  7. Illuminating black holes

    NASA Astrophysics Data System (ADS)

    Barr, Ian A.; Bull, Anne; O’Brien, Eileen; Drillsma-Milgrom, Katy A.; Milgrom, Lionel R.

    2016-07-01

    Two-dimensional shadows formed by illuminating vortices are shown to be visually analogous to the gravitational action of black holes on light and surrounding matter. They could be useful teaching aids demonstrating some of the consequences of general relativity.

  8. Black hole accretion.

    PubMed

    Narayan, Ramesh; Quataert, Eliot

    2005-01-01

    Black holes are most often detected by the radiation produced when they gravitationally pull in surrounding gas, in a process called accretion. The efficiency with which the hot gas radiates its thermal energy strongly influences the geometry and dynamics of the accretion flow. Both radiatively efficient thin disks and radiatively inefficient thick disks are observed. When the accreting gas gets close to the central black hole, the radiation it produces becomes sensitive to the spin of the hole and the presence of an event horizon. Analysis of the luminosities and spectra of accreting black holes has yielded tantalizing evidence for both rotating holes and event horizons. Numerical simulations imply that the relativistic jets often seen from accreting black holes may be powered in part by the spin of the hole. PMID:15637269

  9. Janus black holes

    NASA Astrophysics Data System (ADS)

    Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.

    2011-10-01

    In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.

  10. The Illinois Black Codes.

    ERIC Educational Resources Information Center

    Bridges, Roger D.; Daley, Harry

    1996-01-01

    Presents an excellent lesson plan discussing the repressive racial legislation that remained enforced in Illinois even after the repeal of slavery. Background material also covers the black communities' response to these racist laws. Includes teaching suggestions, handouts, and activities. (MJP)

  11. The Most Massive Black Holes in Small Galaxies

    NASA Astrophysics Data System (ADS)

    van den Bosch, Remco

    2012-10-01

    Massive galaxies represent the extreme of galaxy formation and contain the most massive black holes {BH}, as reflected in the scaling relations of BH masses with galaxy velocity dispersions {M-sigma} and luminosities {M-L}. Our spectroscopic survey of 600 nearby galaxies revealed 17 galaxies with extremely high velocity dispersions {indicating BH masses of 10^10 solar masses} and at the same time shockingly small sizes {<2 kpc} and {bulge} luminosities. For one of these galaxies archival HST imaging allowed us to measure an extremely big BH mass of 23 billion solar masses, and confirm it is hosted by a small disk-dominated galaxy of only 90 billion solar masses in stars. This demonstrates that the BH in this system did not co-evolve with its host galaxy the way others are thought to have. It is imperative to go beyond a single anecdotal example to a real sample of galaxies with small bulges and suspected monster black holes. Here we propose to obtain HST imaging of the other 16 galaxies. The WFC3 imaging is required to resolve their small bulge and put accurate constraints {in combination with our spectroscopy} on their black hole mass. A significant sample of compact galaxies with very high black hole masses would be in stark conflict with the popular co-evolution picture and could form the missing link between local galaxies and the quiescent compact nugget galaxies found at z 2.

  12. Helical superconducting black holes.

    PubMed

    Donos, Aristomenis; Gauntlett, Jerome P

    2012-05-25

    We construct novel static, asymptotically five-dimensional anti-de Sitter black hole solutions with Bianchi type-VII(0) symmetry that are holographically dual to superconducting phases in four spacetime dimensions with a helical p-wave order. We calculate the precise temperature dependence of the pitch of the helical order. At zero temperature the black holes have a vanishing entropy and approach domain wall solutions that reveal homogenous, nonisotropic dual ground states with an emergent scaling symmetry.

  13. Beyond Black and White.

    ERIC Educational Resources Information Center

    Comer, James P.

    Black and white conflict is a by-product of a more basic problem: the failure of this society to develop a social system that enables all people to meet their basic human needs at a reasonable level. Until this is done, we will not be able to move beyond black and white. The underlying problem is related to a sudden acceleration of human history…

  14. Can Blacks Be Racists? Black-on-Black Principal Abuse in an Urban School Setting

    ERIC Educational Resources Information Center

    Khalifa, Muhammad

    2015-01-01

    This study examines Black student and parental perceptions of exclusionary practices of Black school principals. I ask why students and parents viewed two Black principals as contributing to abusive and exclusionary school environments that marginalized Black students. After a two-year ethnographic study, it was revealed that exclusionary…

  15. Award-Winning Etching Process Cuts Solar Cell Costs (Fact Sheet)

    SciTech Connect

    Not Available

    2013-08-01

    NREL scientists have invented the 'black silicon' nanocatalytic wet-chemical etch, an inexpensive, one-step process that literally turns the solar cells black, allowing them to absorb more than 98% of incident sunlight. The process costs just a few cents per watt of solar-cell power-producing capacity. Increases in manufactured cell efficiencies of up to 0.8% are possible because of the reduced reflectance of black silicon. This would reduce silicon solar module costs by $5-$10 per module.

  16. Charged Galileon black holes

    SciTech Connect

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar E-mail: christos.charmousis@th.u-psud.fr

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  17. Braneworld Black Holes

    NASA Astrophysics Data System (ADS)

    Whisker, Richard

    2008-10-01

    In this thesis we investigate black holes in the Randall-Sundrum braneworld scenario. We begin with an overview of extra-dimensional physics, from the original proposal of Kaluza and Klein up to the modern braneworld picture of extra dimensions. A detailed description of braneworld gravity is given, with particular emphasis on its compatibility with experimental tests of gravity. We then move on to a discussion of static, spherically symmetric braneworld black hole solutions. Assuming an equation of state for the ``Weyl term'', which encodes the effects of the extra dimension, we are able to classify the general behaviour of these solutions. We then use the strong field limit approach to investigate the gravitational lensing properties of some candidate braneworld black hole solutions. It is found that braneworld black holes could have significantly different observational signatures to the Schwarzschild black hole of standard general relativity. Rotating braneworld black hole solutions are also discussed, and we attempt to generate rotating solutions from known static solutions using the Newman-Janis complexification ``trick''.

  18. Searching for Black Holes

    NASA Technical Reports Server (NTRS)

    Garcia, M.

    1998-01-01

    Our UV/VIS work concentrates on black hole X-ray nova. These objects consist of two stars in close orbit, one of which we believe is a black hole - our goal is to SHOW that one is a black hole. In order to reach this goal we carry out observations in the Optical, UV, IR and X-ray bands, and compare the observations to theoretical models. In the past year, our UV/VIS grant has provided partial support (mainly travel funds and page charges) for work we have done on X-ray nova containing black holes and neutron stars. We have been very successful in obtaining telescope time to support our project - we have completed approximately a dozen separate observing runs averaging 3 days each, using the MMT (5M), Lick 3M, KPNO 2.1M, CTIO 4M, CTIO 1.5M, and the SAO/WO 1.2M telescopes. These observations have allowed the identification of one new black hole (Nova Oph 1977), and allowed the mass of another to be measured (GS2000+25). Perhaps our most exciting new result is the evidence we have gathered for the existence of 'event horizons' in black hole X-ray nova.

  19. Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods. Part 5. Effects of nonoriginal surface coatings into the nature and distribution of chromium and sulfur species in chrome yellow paints.

    PubMed

    Monico, Letizia; Janssens, Koen; Vanmeert, Frederik; Cotte, Marine; Brunetti, Brunetto Giovanni; Van der Snickt, Geert; Leeuwestein, Margje; Salvant Plisson, Johanna; Menu, Michel; Miliani, Costanza

    2014-11-01

    The darkening of lead chromate yellow pigments, caused by a reduction of the chromate ions to Cr(III) compounds, is known to affect the appearance of several paintings by Vincent van Gogh. In previous papers of this series, we demonstrated that the darkening is activated by light and depends on the chemical composition and crystalline structure of the pigments. In this work, the results of Part 2 are extended and complemented with a new study aimed at deepening the knowledge of the nature and distribution of Cr and S species at the interface between the chrome yellow paint and the nonoriginal coating layer. For this purpose, three microsamples from two varnished paintings by Van Gogh and a waxed low relief by Gauguin (all originally uncoated) have been examined. Because nonoriginal coatings are often present in artwork by Van Gogh and contemporaries, the understanding of whether or not their application has influenced the morphological and/or physicochemical properties of the chrome yellow paint underneath is relevant in view of the conservation of these masterpieces. In all the samples studied, microscopic X-ray fluorescence (μ-XRF) and X-ray absorption near edge structure (μ-XANES) investigations showed that Cr(III)-based alteration products are present in the form of grains inside the coating (generally enriched of S species) and also homogeneously widespread at the paint surface. The distribution of Cr(III) species may be explained by the mechanical friction caused by the coating application by brush that picked up and redistributed the superficial Cr compounds, likely already present in the reduced state as result of the photodegradation process. The analysis of the XANES profiles allowed us to obtain new insights into the nature of the Cr(III) alteration products, that were identified as sulfate-, oxide-, organo-metal-, and chloride-based compounds. Building upon the knowledge acquired through the examination of original paint samples and from the

  20. Modeling motion of a small black hole through a star or a planet

    NASA Astrophysics Data System (ADS)

    Turova, Victoria; Panin, Alexander

    2012-10-01

    In some scenarios of Big Bang the fluctuations of density in early universe result in the formation of various sized primordial black holes. The black holes of mass range 10^10 -10^22 kg are suitable candidates for a dark matter (or at least for a part of it). Such black holes could from time to time pass via Solar system or Sun or even Earth. What would a trajectory of a small black hole passing through Sun or through Earth look like? Would a black hole slow down and stuck consuming matter and causing cataclysmic collapse of Earth or Sun, or would it just pass? What other effects would take place? We model computationally a motion of a small black hole moving with various initial velocities (10- 1000 km/sec) through a planet-like and a star-like body of various density distributions. The results of this modeling are presented.

  1. Radio detections during two state transitions of the intermediate-mass black hole HLX-1.

    PubMed

    Webb, Natalie; Cseh, David; Lenc, Emil; Godet, Olivier; Barret, Didier; Corbel, Stephane; Farrell, Sean; Fender, Robert; Gehrels, Neil; Heywood, Ian

    2012-08-01

    Relativistic jets are streams of plasma moving at appreciable fractions of the speed of light. They have been observed from stellar-mass black holes (~3 to 20 solar masses, M(⊙)) as well as supermassive black holes (~10(6) to 10(9) M(⊙)) found in the centers of most galaxies. Jets should also be produced by intermediate-mass black holes (~10(2) to 10(5) M(⊙)), although evidence for this third class of black hole has, until recently, been weak. We report the detection of transient radio emission at the location of the intermediate-mass black hole candidate ESO 243-49 HLX-1, which is consistent with a discrete jet ejection event. These observations also allow us to refine the mass estimate of the black hole to be between ~9 × 10(3) M(⊙) and ~9 × 10(4) M(⊙).

  2. Black Sea in Bloom

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image shows bright, turquoise-colored swirls across the surface of the Black Sea, signifying the presence of a large phytoplankton bloom. Scientists have observed similar blooms recurring annually, roughly this same time of year. The Sea of Azov, which is the smaller body of water located just north of the Black Sea in this image, also shows a high level of biological activity currently ongoing. The brownish pixels in the Azov are probably sediments carried in from high waters upstream. This scene was acquired by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on May 4, 2002. According to the Black Sea Environment Programme's Marine Hydrophysical Institute, the Black Sea is 'one of the marine areas of the world most damaged by human activities.' The coastal zone around these Eastern European inland water bodies is densely populated-supporting a permanent population of roughly 16 million people and another 4 million tourists each year. Six countries border with the Black Sea, including Ukraine to the north, Russia and Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west. Because it is isolated from the world's oceans, and because there is an extensive drainage network of rivers that empty into it, the Black Sea has a unique and delicate water balance which is very important for supporting its marine ecosystem. Of particular concern to scientists is the salinity, water level, and nutrient levels of the Black Sea's waters, all of which are, unfortunately, being impacted by human activities. Within the last three decades the combination of increased nutrient loads from human sources together with pollution and over-harvesting of fisheries has resulted in a sharp decline in water quality. Scientists from each of the Black Sea's bordering nations are currently working together to study the issues and formulate a joint, international strategy for saving this unique marine ecosystem

  3. Black Sea Becomes Turquoise

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image shows bright, turquoise-colored swirls across the surface of the Black Sea, signifying the presence of a large phytoplankton bloom. Scientists have observed similar blooms recurring annually, roughly this same time of year. The Sea of Azov, which is the smaller body of water located just north of the Black Sea in this image, also shows a high level of color variance. The brownish pixels in the Azov are probably due to sediments carried in from high waters and snowmelt from upstream. This scene was acquired by the Moderate Resolution Imaging Spectroradiometer, flying aboard NASA's Terra satellite, on May 14, 2002. According to the Black Sea Environment Programme's Marine Hydrophysical Institute, the Black Sea is ?one of the marine areas of the world most damaged by human activities.? The coastal zone around these Eastern European inland water bodies is densely populated'supporting a permanent population of roughly 16 million people and another 4 million tourists each year. Six countries border with the Black Sea, including Ukraine to the north, Russia and Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west. Because it is isolated from the world's oceans, and because there is an extensive drainage network of rivers that empty into it, the Black Sea has a unique and delicate water balance which is very important for supporting its marine ecosystem. Of particular concern to scientists is the salinity, water level, and nutrient levels of the Black Sea's waters, all of which are, unfortunately, being impacted by human activities. Within the last three decades the combination of increased nutrient loads from human sources together with pollution and over-harvesting of fisheries has resulted in a sharp decline in water quality. Scientists from each of the Black Sea's bordering nations are currently working together to study the issues and formulate a joint, international strategy for saving this unique marine ecosystem

  4. Solar greenhouse

    SciTech Connect

    Baldwin, R.E.

    1980-04-01

    A solar greenhouse is disclosed wherein plants are grown and utilized as collectors to absorb solar radiation and produce heat laden humidified air through the process of evapotranspiration. This humidified air is then further heated by solar energy. Energy is then extracted from the humidified air by cooling the air and condensing the water vapor within the air. The extracted heat can then be stored and utilized as required to heat the greenhouse and plants.

  5. The formation and evolution of massive black holes.

    PubMed

    Volonteri, M

    2012-08-01

    The past 10 years have witnessed a change of perspective in the way astrophysicists think about massive black holes (MBHs), which are now considered to have a major role in the evolution of galaxies. This appreciation was driven by the realization that black holes of millions of solar masses and above reside in the center of most galaxies, including the Milky Way. MBHs also powered active galactic nuclei known to exist just a few hundred million years after the Big Bang. Here, I summarize the current ideas on the evolution of MBHs through cosmic history, from their formation about 13 billion years ago to their growth within their host galaxies.

  6. The formation and evolution of massive black holes.

    PubMed

    Volonteri, M

    2012-08-01

    The past 10 years have witnessed a change of perspective in the way astrophysicists think about massive black holes (MBHs), which are now considered to have a major role in the evolution of galaxies. This appreciation was driven by the realization that black holes of millions of solar masses and above reside in the center of most galaxies, including the Milky Way. MBHs also powered active galactic nuclei known to exist just a few hundred million years after the Big Bang. Here, I summarize the current ideas on the evolution of MBHs through cosmic history, from their formation about 13 billion years ago to their growth within their host galaxies. PMID:22859482

  7. Solar Physics

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    The areas of emphasis are: (1) develop theoretical models of the transient release of magnetic energy in the solar atmosphere, e.g., in solar flares, eruptive prominences, coronal mass ejections, etc.; (2) investigate the role of the Sun's magnetic field in the structuring of solar corona by the development of three-dimensional numerical models that describe the field configuration at various heights in the solar atmosphere by extrapolating the field at the photospheric level; (3) develop numerical models to investigate the physical parameters obtained by the ULYSSES mission; (4) develop numerical and theoretical models to investigate solar activity effects on the solar wind characteristics for the establishment of the solar-interplanetary transmission line; and (5) develop new instruments to measure solar magnetic fields and other features in the photosphere, chromosphere transition region and corona. We focused our investigation on the fundamental physical processes in solar atmosphere which directly effect our Planet Earth. The overall goal is to establish the physical process for the Sun-Earth connections.

  8. Solar Simulator

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Oriel Corporation's simulators have a high pressure xenon lamp whose reflected light is processed by an optical system to produce a uniform solar beam. Because of many different types of applications, the simulators must be adjustable to replicate many different areas of the solar radiation spectrum. Simulators are laboratory tools for such purposes as testing and calibrating solar cells, or other solar energy systems, testing dyes, paints and pigments, pharmaceuticals and cosmetic preparations, plant and animal studies, food and agriculture studies and oceanographic research.

  9. Thermodynamic black di-rings

    SciTech Connect

    Iguchi, Hideo; Mishima, Takashi

    2010-10-15

    Previously the five dimensional S{sup 1}-rotating black rings have been superposed in a concentric way by some solitonic methods, and regular systems of two S{sup 1}-rotating black rings were constructed by the authors and then Evslin and Krishnan (we called these solutions 'black di-rings'). In this place we show some characteristics of the solutions of five dimensional black di-rings, especially in thermodynamic equilibrium. After the summary of the di-ring expressions and their physical quantities, first we comment on the equivalence of the two different solution sets of the black di-rings. Then the existence of thermodynamic black di-rings is shown, in which both isothermality and isorotation between the inner black ring and the outer black ring are realized. We also give detailed analysis of peculiar properties of the thermodynamic black di-ring including discussion about a certain kind of thermodynamic stability (instability) of the system.

  10. Black rings at large D

    NASA Astrophysics Data System (ADS)

    Tanabe, Kentaro

    2016-02-01

    We study the effective theory of slowly rotating black holes at the infinite limit of the spacetime dimension D. This large D effective theory is obtained by integrating the Einstein equation with respect to the radial direction. The effective theory gives equations for non-linear dynamical deformations of a slowly rotating black hole by effective equations. The effective equations contain the slowly rotating Myers-Perry black hole, slowly boosted black string, non-uniform black string and black ring as stationary solutions. We obtain the analytic solution of the black ring by solving effective equations. Furthermore, by perturbation analysis of effective equations, we find a quasinormal mode condition of the black ring in analytic way. As a result we confirm that thin black ring is unstable against non-axisymmetric perturbations. We also include 1 /D corrections to the effective equations and discuss the effects by 1 /D corrections.

  11. STIS RECORDS A BLACK HOLE'S SIGNATURE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The colorful 'zigzag' on the right is not the work of a flamboyant artist, but the signature of a supermassive black hole in the center of galaxy M84, discovered by Hubble Space Telescope's Space Telescope Imaging Spectrograph (STIS). The image on the left, taken with Hubble's Wide Field Planetary and Camera 2 shows the core of the galaxy where the suspected black hole dwells. Astronomers mapped the motions of gas in the grip of the black hole's powerful gravitational pull by aligning the STIS's spectroscopic slit across the nucleus in a single exposure. The STIS data on the right shows the rotational motion of stars and gas along the slit. The change in wavelength records whether an object is moving toward or away from the observer. The larger the excursion from the centerline -- as seen as a green and yellow picture element (pixels) along the center strip, the greater the rotational velocity. If no black hole were present, the line would be nearly vertical across the scan. Instead, STIS's detector found the S-shape at the center of this scan, indicating a rapidly swirling disk of trapped material encircling the black hole. Along the S-shape from top to bottom, velocities skyrocket as seen in the rapid, dramatic swing to the left (blueshifted or approaching gas), then the region in the center simultaneously records the enormous speeds of the gas both approaching and receding for orbits in the immediate vicinity of the black hole, and then an equivalent swing from the right, back to the center line. STIS measures a velocity of 880,000 miles per hour (400 kilometers per second) within 26 light-years of the galaxy's center, where the black hole dwells. This motion allowed astronomers to calculate that the black hole contains at least 300 million solar masses. (Just as the mass of our Sun can be calculated from the orbital radii and speeds of the planets.) This observation demonstrates a direct connection between a supermassive black hole and activity (such as radio

  12. Black holes and beyond

    NASA Astrophysics Data System (ADS)

    Mathur, Samir D.

    2012-11-01

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome 'remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a 'fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole.

  13. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, John

    2009-01-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  14. Infrared Spectroscopy of Black Hole Candidates

    NASA Astrophysics Data System (ADS)

    Colgan, S. W. J.; Cotera, A. S.; Maloney, P. R.; Hollenbach, D. J.

    2000-05-01

    ISO LWS and SWS observations of the solar mass black hole candidates 1E1740.7-2942 and GRS1758-258 are presented. For 1E1740.7-2942, it has been suggested that the luminosity is provided in whole or part by Bondi-Hoyle accretion from a surrounding black hole (Bally & Leventhal 1991, Nat, 353, 234). Maloney etal. (1997, ApJ 482, L41) have predicted that detectable far-infrared line emission from [OI] (63 microns), [CII] (158 microns), [SiII] (35 microns) and other lines will arise from black holes which are embedded in molecular clouds. No strong line emission associated with either 1E1740.7-2942 or GRS1758-258 was detected, implying either that 1) these sources are not embedded in dense molecular clouds, or 2) that their average X-ray luminosity over the past 100 years is significantly lower than its current value. The measured upper limits to the line fluxes are compared with the models of Maloney etal. to constrain the properties of the ISM in the vicinity of these X-ray sources. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.

  15. Solar Technologies

    ERIC Educational Resources Information Center

    von Hippel, Frank; Williams, Robert H.

    1975-01-01

    As fossil fuels decrease in availability and environmental concerns increase, soalr energy is becoming a potential major energy source. Already solar energy is used for space heating in homes. Proposals for solar-electric generating systems include land-based or ocean-based collectors and harnessing wind and wave power. Photosynthesis can also…

  16. Solar Sprint

    ERIC Educational Resources Information Center

    Tabor, Richard; Anderson, Stephen

    2007-01-01

    In the "Solar Sprint" activity, students design, test, and race a solar-powered car built with Legos. The use of ratios is incorporated to simulate the actual work of scientists and engineers. This method encourages fourth-grade students to think about multiple variables and stimulates their curiosity when an activity doesn't come out as…

  17. Solar Eclipse

    Atmospheric Science Data Center

    2013-04-19

    ...   View Larger Image On June 10, 2002 the Moon obscured the central portion of the solar disk in a phenomenon known as an annular solar eclipse. Partial phases of the eclipse were visible throughout much of southeast Asia and North ...

  18. Strengths of Black Families: A Black Community's Perspective.

    ERIC Educational Resources Information Center

    Royse, David D.; Turner, Gladys T.

    1980-01-01

    Research on Black families should use a nondeviant perspective. Strengths in Black families, such as kinship, work orientation, adaptability of family roles, achievement, and religious orientation, are too often overlooked. (JAC)

  19. Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.

    PubMed

    Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-11-28

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.

  20. Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.

    PubMed

    Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-11-28

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet. PMID:25378461

  1. Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods. 3. Synthesis, characterization, and detection of different crystal forms of the chrome yellow pigment.

    PubMed

    Monico, Letizia; Janssens, Koen; Miliani, Costanza; Brunetti, Brunetto Giovanni; Vagnini, Manuela; Vanmeert, Frederik; Falkenberg, Gerald; Abakumov, Artem; Lu, Yinggang; Tian, He; Verbeeck, Johan; Radepont, Marie; Cotte, Marine; Hendriks, Ella; Geldof, Muriel; van der Loeff, Luuk; Salvant, Johanna; Menu, Michel

    2013-01-15

    The painter, Vincent van Gogh, and some of his contemporaries frequently made use of the pigment chrome yellow that is known to show a tendency toward darkening. This pigment may correspond to various chemical compounds such as PbCrO(4) and PbCr(1-x)S(x)O(4), that may each be present in various crystallographic forms with different tendencies toward degradation. Investigations by X-ray diffraction (XRD), mid-Fourier Transform infrared (FTIR), and Raman instruments (benchtop and portable) and synchrotron radiation-based micro-XRD and X-ray absorption near edge structure spectroscopy performed on oil-paint models, prepared with in-house synthesized PbCrO(4) and PbCr(1-x)S(x)O(4), permitted us to characterize the spectroscopic features of the various forms. On the basis of these results, an extended study has been carried out on historic paint tubes and on embedded paint microsamples taken from yellow-orange/pale yellow areas of 12 Van Gogh paintings, demonstrating that Van Gogh effectively made use of different chrome yellow types. This conclusion was also confirmed by in situ mid-FTIR investigations on Van Gogh's Portrait of Gauguin (Van Gogh Museum, Amsterdam). PMID:23050489

  2. Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods. 3. Synthesis, characterization, and detection of different crystal forms of the chrome yellow pigment.

    PubMed

    Monico, Letizia; Janssens, Koen; Miliani, Costanza; Brunetti, Brunetto Giovanni; Vagnini, Manuela; Vanmeert, Frederik; Falkenberg, Gerald; Abakumov, Artem; Lu, Yinggang; Tian, He; Verbeeck, Johan; Radepont, Marie; Cotte, Marine; Hendriks, Ella; Geldof, Muriel; van der Loeff, Luuk; Salvant, Johanna; Menu, Michel

    2013-01-15

    The painter, Vincent van Gogh, and some of his contemporaries frequently made use of the pigment chrome yellow that is known to show a tendency toward darkening. This pigment may correspond to various chemical compounds such as PbCrO(4) and PbCr(1-x)S(x)O(4), that may each be present in various crystallographic forms with different tendencies toward degradation. Investigations by X-ray diffraction (XRD), mid-Fourier Transform infrared (FTIR), and Raman instruments (benchtop and portable) and synchrotron radiation-based micro-XRD and X-ray absorption near edge structure spectroscopy performed on oil-paint models, prepared with in-house synthesized PbCrO(4) and PbCr(1-x)S(x)O(4), permitted us to characterize the spectroscopic features of the various forms. On the basis of these results, an extended study has been carried out on historic paint tubes and on embedded paint microsamples taken from yellow-orange/pale yellow areas of 12 Van Gogh paintings, demonstrating that Van Gogh effectively made use of different chrome yellow types. This conclusion was also confirmed by in situ mid-FTIR investigations on Van Gogh's Portrait of Gauguin (Van Gogh Museum, Amsterdam).

  3. Rotating black droplet

    NASA Astrophysics Data System (ADS)

    Fischetti, Sebastian; Santos, Jorge E.

    2013-07-01

    We construct the gravitational dual, in the Unruh state, of the "jammed" phase of a CFT at strong coupling and infinite N on a fixed five-dimensional rotating Myers-Perry black hole with equal angular momenta. When the angular momenta are all zero, the solution corresponds to the five-dimensional generalization of the solution first studied in [1]. In the extremal limit, when the angular momenta of the Myers-Perry black hole are maximum, the Unruh, Boulware and Hartle-Hawking states degenerate. We give a detailed analysis of the corresponding holographic stress energy tensor for all values of the angular momenta, finding it to be regular at the horizon in all cases. We compare our results with existent literature on thermal states of free field theories on black hole backgrounds.

  4. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  5. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2010-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wove detection, testing general relativity, and astrophysics.

  6. Turbulent black holes.

    PubMed

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  7. Turbulent black holes.

    PubMed

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids. PMID:25768746

  8. Bringing Black Holes Home

    NASA Astrophysics Data System (ADS)

    Furmann, John M.

    2003-03-01

    Black holes are difficult to study because they emit no light. To overcome this obstacle, scientists are trying to recreate a black hole in the laboratory. The article gives an overview of the theories of Einstein and Hawking as they pertain to the construction of the Large Hadron Collider (LHC) near Geneva, Switzerland, scheduled for completion in 2006. The LHC will create two beams of protons traveling in opposing directions that will collide and create a plethora of scattered elementary particles. Protons traveling in opposite directions at very high velocities may create particles that come close enough to each other to feel their compacted higher dimensions and create a mega force of gravity that can create tiny laboratory-sized black holes for fractions of a second. The experiments carried out with LHC will be used to test modern string theory and relativity.

  9. Black ring deconstruction

    SciTech Connect

    Gimon, Eric; Gimon, Eric G.; Levi, Thomas S.

    2007-06-22

    We present a sample microstate for a black ring in four and five dimensional language. The microstate consists of a black string microstate with an additional D6-brane. We show that with an appropriate choice of parameters the piece involving the black string microstate falls down a long AdS throat, whose M-theory lift is AdS_3 x S2. We wrap a spinning dipole M2-brane on the S2 in the probe approximation. In IIA, this corresponds to a dielectric D2-brane carrying only D0-charge. We conjecture this is the firstapproximation to a cloud of D0-branes blowing up due to their non-abelian degrees of freedom and the Myers effect.

  10. Design fabrication and testing of ceramic solar absorber plates

    SciTech Connect

    Sisson, J.C.

    1983-01-01

    The effects of fabrication procedures on the thermal performance of various ceramic systems for active solar applications were investigated. A shale-based structural clay body was used as a standard. This body was also coated with silicon carbide, a glossy black glaze and a matte black glaze. Metal samples used included copper, aluminum and aluminum coated with a flat black paint. Experiments were performed using a solar test box linked to an automated data acquisition system. Temperatures of samples were recorded at 3 min. intervals for 4 h solar periods. An F-statistical analysis was performed on the resulting data and was correlated with total solar emittance, total solar reflectance and monochromatic reflectance as a function of incident wavelength. The information above was also utilized in developing a computer model used to simulate the performance of various materials in active solar testing. Results suggest that a structural clay body fired to maturity and coated with a matte black glaze could be commercially useful for applications requiring large quantities of heated water.

  11. A thermal control surface for the Solar Orbiter

    NASA Astrophysics Data System (ADS)

    Doherty, Kevin A. J.; Carton, James G.; Norman, Andrew; McCaul, Terry; Twomey, Barry; Stanton, Kenneth T.

    2015-12-01

    A high-absorptivity/high-emissivity (flat absorber) bone char-based thermal control surface known as SolarBlack has been developed for use on rigid and flexible metallic substrates, including titanium, aluminium, copper, stainless steel, Inconel and magnesium alloys. This work describes the thermo-optical properties, stability, and qualification of this surface for use on the European Space Agency's Solar Orbiter mission. SolarBlack is deposited using a proprietry coating technique known as CoBlast and currently stands as the baseline coating for the spacecraft's front surface heat-shield, which is composed of 50 μm titanium foils (1.3×0.3 m) that have been constructed to cover the 3.1×2.4 m2 shield. The heat shield makes use of the material's highly stable ratio of solar absorptance to near-normal thermal emissivity (αs/εN) as well as its low electrical resistivity to regulate both temperature and electrostatic dissipation in service. SolarBlack also currently stands as the baseline surface for the High-gain and Medium-gain antennae as well as a number of other components on the spacecraft. The thermo-optical stability of SolarBlack was determined using the STAR Facility space environment simulator in ESTEC., Material characterisation was carried out using: SEM, UV/Vis/NIR spectrometry, and IR emissometry. The coating performance was verified on the Structural Thermal Model using ESA's Large Space Simulator.

  12. Slowly balding black holes

    SciTech Connect

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-15

    The 'no-hair' theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively ''frozen in'' the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes N{sub B}=e{Phi}{sub {infinity}}/({pi}c({h_bar}/2{pi})), where {Phi}{sub {infinity}}{approx_equal}2{pi}{sup 2}B{sub NS}R{sub NS}{sup 3}/(P{sub NS}c) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole's magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  13. Slowly balding black holes

    NASA Astrophysics Data System (ADS)

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-01

    The “no-hair” theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively “frozen in” the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes NB=eΦ∞/(πcℏ), where Φ∞≈2π2BNSRNS3/(PNSc) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole’s magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  14. Sowing Black Hole Seeds: Forming Direct Collapse Black Holes With Realistic Lyman-Werner Radiation Fields in Cosmological Simulations

    NASA Astrophysics Data System (ADS)

    Holley-Bockelmann, Kelly; Dunn, Glenna; Bellovary, Jillian M.; Christensen, Charlotte

    2016-01-01

    Luminous quasars detected at redshifts z > 6 require that the first black holes form early and grow to ~109 solar masses within one Gyr. Our work uses cosmological simulations to study the formation and early growth of direct collapse black holes. In the pre-reionization epoch, molecular hydrogen (H2) causes gas to fragment and form Population III stars, but Lyman-Werner radiation can suppress H2 formation and allow gas to collapse directly into a massive black hole. The critical flux required to inhibit H2 formation, Jcrit, is hotly debated, largely due to the uncertainties in the source radiation spectrum, H2 self-shielding, and collisional dissociation rates. Here, we test the power of the direct collapse model in a non-uniform Lyman-Werner radiation field, using an updated version of the SPH+N-body tree code Gasoline with H2 non-equilibrium abundance tracking, H2 cooling, and a modern SPH implementation. We vary Jcrit from 30 to 104 J21 to study the effect on seed black holes, focusing on black hole formation as a function of environment, halo mass, metallicity, and proximity of the Lyman-Werner source. We discuss the constraints on massive black hole occupation fraction in the quasar epoch, and implications for reionization, high-redshift X-ray background radiation, and gravitational waves.

  15. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.

    2010-01-01

    Black-hole mergers take place in regions of very strong and dynamical gravitational fields, and are among the strongest sources of gravitational radiation. Probing these mergers requires solving the full set of Einstein's equations of general relativity numerically. For more than 40 years, progress towards this goal has been very slow, as numerical relativists encountered a host of difficult problems. Recently, several breakthroughs have led to dramatic progress, enabling stable and accurate calculations of black-hole mergers. This article presents an overview of this field, including impacts on astrophysics and applications in gravitational wave data analysis.

  16. Characterizing Black Hole Mergers

    NASA Technical Reports Server (NTRS)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  17. Infinitely coloured black holes

    NASA Astrophysics Data System (ADS)

    Mavromatos, Nick E.; Winstanley, Elizabeth

    2000-04-01

    We formulate the field equations for SU (icons/Journals/Common/infty" ALT="infty" ALIGN="TOP"/> ) Einstein-Yang-Mills theory, and use an analytic approximation to elucidate the properties of spherically symmetric black hole solutions. This model may be motivated by string theory considerations, given the enormous gauge symmetries which characterize string theory. The solutions simplify considerably in the presence of a negative cosmological constant, particularly for the limiting cases of a very large cosmological constant or very small gauge field. The black holes possess infinite amounts of gauge field hair, and we speculate on possible consequences of this for quantum decoherence, which, however, we do not tackle here.

  18. Black-pigmented sputum

    PubMed Central

    Martínez-Girón, Rafael; Mosquera-Martínez, Joaquín; Martínez-Torre, Santiago

    2013-01-01

    Black-pigmented sputum, also called “melanoptysis,” is a symptom that may be observed in certain pathologies such us coal workers’ pneumoconiosis (anthracosis). The cavitation and liquefaction of a fibrosed mass by an infectious process (tuberculosis, infections by anaerobes, etc.) or by ischemic necrosis may cause expectoration of a blackish secretion. We report the case of a patient with labor precedents as a coal worker, from whom abundant black sputum was obtained in the course of an incidental expectoration. Cyto-histological findings are shown and a differential diagnosis is established. PMID:24648674

  19. Euclidean black hole vortices

    NASA Technical Reports Server (NTRS)

    Dowker, Fay; Gregory, Ruth; Traschen, Jennie

    1991-01-01

    We argue the existence of solutions of the Euclidean Einstein equations that correspond to a vortex sitting at the horizon of a black hole. We find the asymptotic behaviors, at the horizon and at infinity, of vortex solutions for the gauge and scalar fields in an abelian Higgs model on a Euclidean Schwarzschild background and interpolate between them by integrating the equations numerically. Calculating the backreaction shows that the effect of the vortex is to cut a slice out of the Schwarzschild geometry. Consequences of these solutions for black hole thermodynamics are discussed.

  20. REPORT TO CONGRESS ON BLACK CARBON

    EPA Science Inventory

    The Report to Congress on Black Carbon describes domestic and international sources of black carbon emissions, and summarizes available scientific information on the climate effects of black carbon. Further, the Report evaluates available black carbon mitigation options and thei...

  1. Black Television: Avenue of Power

    ERIC Educational Resources Information Center

    Douglas, Pamela

    1973-01-01

    Analyzes a few of the prominent issues in black television, examining public television, commercial television, black ownership of stations, cable television, and some projections for the future. (Author/JM)

  2. Aspects of hairy black holes

    SciTech Connect

    Anabalón, Andrés; Astefanesei, Dumitru

    2015-03-26

    We review the existence of exact hairy black holes in asymptotically flat, anti-de Sitter and de Sitter space-times. We briefly discuss the issue of stability and the charging of the black holes with a Maxwell field.

  3. Conquering the Black Girl Blues.

    PubMed

    Jones, Lani Valencia; Guy-Sheftall, Beverly

    2015-10-01

    An examination of the literature on epidemiology, etiology, and use of services for this population reveals an insufficient application of culturally congruent approaches to intervening with black women. An exploration of the social work practice literature and other relevant fields indicate that black feminist perspectives offer the opportunity to gain a clearer understanding of the intersection and influence of oppression among black women struggling with psychiatric issues and provide a useful framework for mental health practice with this population. This article discusses the evolving black feminist thought and summarizes the scholarship on black women's mental health services needs and utilization issues. The article includes a discussion of black feminisms as an emerging mental health perspective, arguing that black feminist perspectives in therapy provide an ideal framework for services that are responsive to the values and health needs of black women. The article concludes with a case vignette that illustrates some of its points.

  4. Conquering the Black Girl Blues.

    PubMed

    Jones, Lani Valencia; Guy-Sheftall, Beverly

    2015-10-01

    An examination of the literature on epidemiology, etiology, and use of services for this population reveals an insufficient application of culturally congruent approaches to intervening with black women. An exploration of the social work practice literature and other relevant fields indicate that black feminist perspectives offer the opportunity to gain a clearer understanding of the intersection and influence of oppression among black women struggling with psychiatric issues and provide a useful framework for mental health practice with this population. This article discusses the evolving black feminist thought and summarizes the scholarship on black women's mental health services needs and utilization issues. The article includes a discussion of black feminisms as an emerging mental health perspective, arguing that black feminist perspectives in therapy provide an ideal framework for services that are responsive to the values and health needs of black women. The article concludes with a case vignette that illustrates some of its points. PMID:26489355

  5. Black Musicians Leading the Way.

    ERIC Educational Resources Information Center

    Music Educators Journal, 1982

    1982-01-01

    Describes the careers and musical achievements of Blacks who were forerunners in jazz, blues, gospel, music, spirituals, band music, classical music, ragtime, and opera. The list was compiled to provide teachers with historical background information for "Black History Month." (AM)

  6. Solar electricity and solar fuels

    NASA Astrophysics Data System (ADS)

    Spiers, David J.

    1989-04-01

    The nature of solar radiation and its variation with location is described. The distribution of energy in the solar spectrum places immediate limits on the theoretical efficiency of conversion processes, since practical absorbers cannot convert all wavelengths received to useful energy. The principles of solar energy conversion methods are described. Absorption of solar energy can give rise to direct electrical generation, heating, or chemical change. Electrical generation from sunlight can be achieved by photovoltaic systems directly or by thermal systems which use solar heat to drive a heat engine and generator. The technology used and under research for promising ways of producing electricity or fuel from solar energy is described. Photovoltaic technology is established today for remote area, small power applications, and photovoltaic module sales alone are over 100 million dollars per year at present. The photovoltaic market has grown steadily since the mid-1970's, as prices have fallen continuously. Future energy options are briefly described. The merits of a sustainable energy economy, based on renewable energy resources, including solar energy, are emphasized, as this seems to provide the only hope of eliminating the problems caused by the build-up of atmospheric carbon dioxide, acid rain pollution and nuclear waste disposal. There is no doubt that clean fuels which were derived from solar energy and either did not involve carbon dioxide and used atmospheric carbon dioxide as the source dioxide as the source of carbon would be a worthy ideal. Methods described could one day achieve this.

  7. Dance of Two Monster Black Holes

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-03-01

    This past December, researchers all over the world watched an outburst from the enormous black hole in OJ 287 an outburst that had been predicted years ago using the general theory of relativity.Outbursts from Black-Hole OrbitsOJ 287 is one of the largest supermassive black holes known, weighing in at 18 billion solar masses. Located about 3.5 billion light-years away, this monster quasar is bright enough that it was first observed as early as the 1890s. What makes OJ 287 especially interesting, however, is that its light curve exhibits prominent outbursts roughly every 12 years.Diagram illustrating the orbit of the secondary black hole (shown in blue) in OJ 287 from 2000 to 2023. We see outbursts (the yellow bubbles) every time the secondary black hole crosses the accretion disk (shown in red, ina side view) surrounding the primary (the black circle). [Valtonen et al. 2016]What causes the outbursts? Astronomers think that there is a second supermassive black hole, ~100 times smaller, inspiraling as it orbits the central monster and set to merge within the next 10,000 years. In this model, the primary black hole of OJ 287 is surrounded by a hot accretion disk. As the secondary black hole orbits the primary, it regularly punches through this accretion disk, heating the material and causing the release of expanding bubbles of hot gas pulled from the disk. This gas then radiates thermally, causing the outbursts we see.Attempts to model this scenario using Newtonian orbits all fail; the timing of the secondary black holes crossings through the accretion disk (as measured by when we see the outbursts) can only be explained by a model incorporating general-relativistic effects on the orbit. Careful observations and precise timing of these outbursts therefore provide an excellent test of general relativity.Watching a Predicted CrossingThe model of OJ 287 predicted another disk crossing in December 2015, so professional and amateur astronomers around the world readied more

  8. Solar ponds

    SciTech Connect

    Jayadev, T.S.; Edesess, M.

    1980-04-01

    This report first describes the different types of solar ponds including the nonconvecting salt gradient pond and various saltless pond designs. It then discusses the availability and cost of salts for salt gradient ponds, and compares the economics of salty and saltless ponds as a function of salt cost. A simple computational model is developed to approximate solar pond performance. This model is later used to size solar ponds for district heating and industrial process heat applications. For district heating, ponds are sized to provide space conditioning for a group of homes, in different regions of the United States. Size requirements is on the order of one acre for a group of 25 to 50 homes. An economic analysis is performed of solar ponds used in two industrial process heat applications. The analysis finds that solar ponds are competitive when conventional heat sources are priced at $5 per million Btu and expected to rise in price at a rate of 10% per year. The application of solar ponds to the generation of electricity is also discussed. Total solar pond potential for displacing conventional energy sources is estimated in the range of from one to six quadrillion Btu per year in the near and intermediate future.

  9. Solar sail

    SciTech Connect

    Drexler, K.E.

    1986-09-30

    This patent describes a solar sail propulsion system comprising: solar sail means for intercepting light pressure to produce thrust, the solar sail means being a thin metal film; tension truss means having two ends attached at one end to the solar sail means for transferring the thrust from the solar sail and for preventing gross deformation of the solar sail under light pressure, the solar sail means being a plurality of separate generally two-dimensional pieces joined by springs to the tension truss means; a payload attached to the other end of the tension truss means, the tension truss means comprising a plurality of attachment means for attaching shroud lines to the top of the tension truss means and a plurality of the shroud lines attached to the attachment means at one of their ends and the payload at the other; a plurality of reel means attached to the shroud lines for controllably varying the length of the lines; and a plurality of reflective panel means attached to the sail means for controlling the orientation of the system.

  10. Solar ponds

    SciTech Connect

    Jayadev, T.S.; Edesess, M.

    1980-04-01

    The different types of solar ponds are described, including the nonconvecting salt gradient pond and various saltless pond designs. Then the availability and cost of salts for salt gradient ponds are discussed and costs are compared. A simple computational model is developed to approximate solar pond performance. This model is later used to size solar ponds for district heating and industrial process heat applications. For district heating, ponds are sized to provide space conditioning for a group of homes, in different regions of the United States. Size requirement is on the order of one acre for a group of 25 to 50 homes. An economic analysis is performed of solar ponds used in two industrial process heat applications. The analysis finds that solar ponds are competitive when conventional heat sources are priced at $5 per million Btu and expected to rise in price at a rate of 10% per year. The application of solar ponds to the generation of electricity is also discussed. Total solar pond potential for displacing conventional energy sources is estimated in the range of from one to six quadrillion Btu per year in the near and intermediate future.

  11. Unusual satellite data: A black hole?. [International Ultraviolet Explorer observations

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Data obtained by the NASA-launched European Space Agency's International Ultraviolet Explorer satellite suggests the possibility of a massive black hole at the center of some globular clusters (star groups) in our galaxy. Six of these clusters, three of them X-ray sources, were closely examined. Onboard short wavelength UV instrumentation penetrated the background denseness of the clusters 15,000 light years away where radiation, probably from a group of 10 to 20 bright blue stars orbiting the core, was observed. The stars may well be orbiting a massive black hole the size of 1,000 solar systems. The existence of the black hole is uncertain. The dynamics of the stars must be studied first to determine how they rotate in relation to the center of the million-star cluster. This may better indicate what provides the necessary gravitational pull that holds them in orbit.

  12. Accretion of a ghost condensate by black holes

    SciTech Connect

    Frolov, Andrei V.

    2004-09-15

    The intent of this paper is to point out that the accretion of a ghost condensate by black holes could be extremely efficient. We analyze steady-state spherically symmetric flows of the ghost fluid in the gravitational field of a Schwarzschild black hole and calculate the accretion rate. Unlike minimally coupled scalar field or quintessence, the accretion rate is set not by the cosmological energy density of the field, but by the energy scale of the ghost condensate theory. If hydrodynamical flow is established, it could be as high as a tenth of a solar mass per second for 10 MeV scale ghost condensate accreting onto a stellar-sized black hole, which puts serious constraints on the parameters of the ghost condensate model.

  13. Black Male Images in Films

    ERIC Educational Resources Information Center

    Ward, Francis

    1974-01-01

    Argues that the "super" image of the black male in films served three essential purposes: it gave blacks whatever therapy they needed from films; it had hot box office appeal; and it kept white in control of the images blacks have had of themselves. (Author/JM)

  14. Black Responses to Environmental Constraints

    ERIC Educational Resources Information Center

    Paris, Peter

    1978-01-01

    There is general agreement that various types of environmental forces have resulted in the victimization of Black Americans. Victimization implies a condition of passivity. This article challenges that perspective by demonstrating the distinctive role of the Black churches in helping Blacks maintain self-respect and act on their environment.…

  15. Black Psychologists Discuss Behavior Modification.

    ERIC Educational Resources Information Center

    Bardo, Harold R.; And Others

    The primary purpose of this paper is to discuss reasons why blacks should be concerned and actively involved with practices in behavior modification. The concern is that as these techniques are refined it becomes more important to be sure blacks should be involved at all levels of the application of these procedures when other blacks are subjects…

  16. Black Students in White Skins

    ERIC Educational Resources Information Center

    Snell, Joel C.

    2008-01-01

    Of the 281 million Americans, "Scientific American" estimates that White Africans (21% of White Caucasians) have Black heritage. This article discusses the present state of black elite and the transformation of black students in the United States. Some strategies to become a "white" student are also discussed.

  17. Community Attitudes toward Black English

    ERIC Educational Resources Information Center

    Hoover, Mary Rhodes

    1978-01-01

    Describes research in which 28 black parents and community people were polled as to their attitudes toward vernacular and standard Black English. Attitudes were assessed in four domains--school, home, community and playground--and in four channels--reading, speaking, writing and listening. Standard Black English was preferred in all domains and…

  18. Black English: A Community Language.

    ERIC Educational Resources Information Center

    Davis, France A.

    Black English, the particular variation of the English language used by many American Negroes, is frequently condemned as inferior to standard English by arbiters of language usage, but many Negroes find the structures and style of black English satisfactory for their communication needs. Black English is the result of a complex, developmental…

  19. Uncovering Black Womanhood in Engineering

    ERIC Educational Resources Information Center

    Gibson, Sheree L.; Espino, Michelle M.

    2016-01-01

    Despite the growing research that outlines the experiences of Blacks and women undergraduates in engineering, little is known about Black women in this field. The purpose of this qualitative study was to uncover how eight Black undergraduate women in engineering understood their race and gender identities in a culture that can be oppressive to…

  20. Black Athletes at the Millennium.

    ERIC Educational Resources Information Center

    Harrison, C. Keith

    2000-01-01

    Analyzes Harry Edwards' theories and solutions regarding black male athletes, discussing the single-minded pursuit of sports glory by black males to the exclusion of cultural, educational, and social needs. Examines the systemic channeling of black males by American institutions, noting that though this system promotes opportunity for all,…

  1. Black Progress: Convergence or Cleavage?

    ERIC Educational Resources Information Center

    Hill, Robert B.

    1982-01-01

    The popular view of a permanent Black underclass falling farther behind an expanding Black middle class is disputed by empirical evidence that the underclass is experiencing upward mobility. The discrepancy stems from social scientists' overreliance on cross-sectional data rather than longitudinal data in analyzing economic change among Blacks.…

  2. Grant and the Black Soldier.

    ERIC Educational Resources Information Center

    Lambert, Robert G., Jr.

    General Ulysses S. Grant reflected the prevailing views of his community and times concerning social attitudes. Although opposed to slavery, he was not a strong advocate of liberties and rights for black people. Like President Lincoln, Grant at first opposed use of black troops in the Civil War. On July 17, 1862 black recruitment was approved and…

  3. Health Issues Facing Black Women.

    ERIC Educational Resources Information Center

    Reid, Inez Smith

    Black women in the United States experience a high incidence of serious health problems and, as a group, receive insufficient and inadequate medical care. The death rate for black women suffering from breast cancer has increased substantially since 1950. Also of great concern is the high incidence of cervical cancer in low income black women…

  4. Blacks, Science, and American Education.

    ERIC Educational Resources Information Center

    Pearson, Willie, Jr., Ed.; Bechtel, H. Kenneth, Ed.

    Blacks are severely underrepresented in the American scientific community; fewer than two percent of all scientists with doctorates in this country are black. Despite civil rights legislation and integration of schools, school systems still fail to encourage black students to consider and prepare for careers in the sciences. In this book, eight…

  5. African Psychology and Black Personality Testing.

    ERIC Educational Resources Information Center

    Baldwin, Joseph A.

    1987-01-01

    The following instruments for measuring Black personality use the world view and cultural orientations of Africa have been developed and are described: (1) the Black Personality Questionnaire; (2) the Black Preference Inventory; (3) the Black Opinion Scale; (4) the Themes of Black Awareness Test; (5) the Themes Concerning Blacks Test; and (6) the…

  6. Solar industrial process heat: a study of applications and attitudes. Final report

    SciTech Connect

    Wilson, V.

    1981-04-01

    Actual field data are provided on potential near-term (within 5 to 7 years) industrial markets for solar thermal technologies. Data were gathered through site visits to 100 industrial plants, representing fourteen industrial groups, as identified by 2-digit Standard Industrial Classification codes (SICs), and geographically distributed over 31 states. The site specific data suggests several possible near-term market opportunities for solar thermal energy systems. Plants using electricity as their primary fuel for industrial process heat were identified, on the basis of their high fuel prices, as attractive early-entry markets for solar energy. Additional opportunities were reflected in plants that had accomplished much of their conservation plans, or had sizeable percentages of their operating budgets committed to energy expenses. A suitability analysis identified eleven industrial plants as highly suitable for solar thermal applications, they included producers of fluid milk, pottery, canned and bottled soft drinks, fabricated structural metal, refined petroleum, aluminum cans, chrome and nickel plating and stamped frame metal and metal finishings.

  7. Solar Two

    SciTech Connect

    Not Available

    1998-04-01

    Solar Two is a concentrating solar power plant that can supply electric power on demand to the local utility, Southern California Edison Company. It can do so because it operates not only during sunny parts of the day, but it can store enough thermal energy from the sun to operate during cloudy periods and after dark, for up to three hours, at its rated output of 10 megawatts (MW). For the first time ever, a utility scale solar power plant can supply electricity when the utility needs it most, to satisfy the energy requirements of its customers.

  8. Solar chemical process for sludge treatment

    SciTech Connect

    Boyko, M.

    1980-03-04

    A solar chemical process for converting sewer sludge from a gelatinous mass into a manageable product suitable for fertilizer includes the manufacture of a carbonaceous product by treating cellulose waste such as newspaper with sulfuric acid and heating the mixture until the cellulose product becomes substantially black. The black product is mixed with sludge in a ratio to produce a grainy product that can be chlorinated for sterility and spread as fertilizer. In a modified version of the process, coal ash is added to the sludge with the carbonaceous product for its nutrient value, and sand may be added with the coal ash to aid in aeration of the soil.

  9. Newborn Black Holes

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

  10. When Black Holes Collide

    NASA Technical Reports Server (NTRS)

    Baker, John

    2010-01-01

    Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

  11. The Black Freshman Network.

    ERIC Educational Resources Information Center

    Lewis, Jerry J.

    1986-01-01

    Georgia State's minority retention program provides academic and social support for black freshmen by referral to appropriate campus personnel or resources for assistance with academic, financial, personal, social, and career planning problems. It uses peer counseling, faculty mentors, nonacademic staff participation, and social events to…

  12. Black College Enterprise.

    ERIC Educational Resources Information Center

    Roach, Ronald

    1999-01-01

    Under the leadership of President David H. Swinton, Benedict College (North Carolina) has provided leadership and support for local economic development, benefitting both the community and the school. Trustees invested college endowment funds to help save the sole black-owned banking institution in the state, which now promises to become a…

  13. Black History Speech

    ERIC Educational Resources Information Center

    Noldon, Carl

    2007-01-01

    The author argues in this speech that one cannot expect students in the school system to know and understand the genius of Black history if the curriculum is Eurocentric, which is a residue of racism. He states that his comments are designed for the enlightenment of those who suffer from a school system that "hypocritically manipulates Black…

  14. Keeping Black Poetry Alive

    ERIC Educational Resources Information Center

    Mehta, Diane

    2006-01-01

    Thomas Sayers Ellis, assistant professor of creative writing at New York's Sarah Lawrence College, is one of many scholars fighting for the soul of Black poetry, a struggle that takes place largely off-campus. Unless one is accepted into a top-level graduate poetry program, such as Boston University's program or the Iowa Writing Workshop, a poet's…

  15. Moulting Black Holes

    NASA Astrophysics Data System (ADS)

    Bena, Iosif; Chowdhury, Borun D.; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2012-03-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no black holes were thought to exist.

  16. Black hole magnetospheres

    SciTech Connect

    Nathanail, Antonios; Contopoulos, Ioannis

    2014-06-20

    We investigate the structure of the steady-state force-free magnetosphere around a Kerr black hole in various astrophysical settings. The solution Ψ(r, θ) depends on the distributions of the magnetic field line angular velocity ω(Ψ) and the poloidal electric current I(Ψ). These are obtained self-consistently as eigenfunctions that allow the solution to smoothly cross the two singular surfaces of the problem, the inner light surface inside the ergosphere, and the outer light surface, which is the generalization of the pulsar light cylinder. Magnetic field configurations that cross both singular surfaces (e.g., monopole, paraboloidal) are uniquely determined. Configurations that cross only one light surface (e.g., the artificial case of a rotating black hole embedded in a vertical magnetic field) are degenerate. We show that, similar to pulsars, black hole magnetospheres naturally develop an electric current sheet that potentially plays a very important role in the dissipation of black hole rotational energy and in the emission of high-energy radiation.

  17. The Black Studies Debate.

    ERIC Educational Resources Information Center

    Gordon, Jacob U., Ed.; Rosser, James M., Ed.

    Beginning with the selection of Professor Newby, who attempts to reveal the role which historians, perhaps more specifically white historians, have played and continue to play in the perpetuation of racism in American culture, this anthology concludes with an analysis of the present status of Black Studies. W. Arthur Lewis' critical essay attempts…

  18. [Thematic Issue: Black Theatre.

    ERIC Educational Resources Information Center

    Morrison, Carl F., Jr., Ed.

    "Nummo" refers to "the word" or "word force." The aim of this publication is to provide a common forum for the utilization of the word force in exploring the opinions and creations of black community, educational, and professional theatre artists and scholars. This issue includes a play called "The Twilight Dinner" by Lennox Brown; a review of…

  19. Survival: Black/White.

    ERIC Educational Resources Information Center

    Halpern, Florence

    This book was written to communicate to others how the author became involved in the lives of the southeastern black people and how her perception and understanding of them changed as the result of that involvement. The plan of this book is as follows: the first and, by far the longer, part is devoted to descriptions and examples of the way in…

  20. Black at Higher Education

    ERIC Educational Resources Information Center

    Kadi-Hanifi, Karima

    2013-01-01

    This is an exploratory paper, drawing on the author's experiences as well as those of three other black lecturers in Higher Education (HE). Three interviews were carried out, asking the same five questions around themes of concern to the author. These are about the learning and teaching approaches used by these lecturers; their experiences of…

  1. Black Families. Third Edition.

    ERIC Educational Resources Information Center

    McAdoo, Harriette Pipes, Ed.

    The chapters of this collection explore the experiences of black families in the United States and Africa, today and in the past. They are: (1) "African American Families: A Historical Note" (John Hope Franklin); (2) "African American Families and Family Values" (Niara Sudarkasa); (3) "Old-Time Religion: Benches Can't Say 'Amen'" (William Harrison…

  2. Black Phosphorus RF Transistor

    NASA Astrophysics Data System (ADS)

    Wang, Han; Wang, Xiaomu; Xia, Fengnian; Wang, Luhao; Jiang, Hao; Xia, Qiangfei; Chin, Mattew L.; Dubey, Madan; Han, Shu-Jen

    2015-03-01

    Few-layer and thin film form of layered black phosphorus (BP) has recently emerged as a promising material for applications in high performance thin film electronics and infrared optoelectronics. Layered BP offers a ~ 0.3eV bandgap and high mobility, leading to transistor devices with decent on/off ratio and high on-state current density. Here, we demonstrate the GHz frequency operation of black phosphorus field-effect transistor for the first time. BP transistors demonstrated here show excellent current saturation with an on-off ratio exceeding 2 × 103. The S-parameter characterization is performed for the first time on black phosphorus transistors, giving a 12 GHz short-circuit current-gain cut-off frequency and 20 GHz maximum oscillation frequency in 300 nm channel length devices. A current density in excess of 270 mA/mm and DC transconductance above 180 mS/mm are achieved for hole conductions. The results reveal the promising potential of black phosphorus transistors for enabling the next generation thin film transistor technology that can operate in the multi-GHz frequency range and beyond.

  3. Teaching the Black Experience.

    ERIC Educational Resources Information Center

    Kirschenbaum, Howard

    1968-01-01

    Instructional materials and teaching approaches can be used to get students to seriously and constructively confront problems in race relations which they will eventually have to solve. For example, Richard Wright's "Black Boy," an anthology of Negro poetry or a collection of poems on race relations, and such films as "Where is Prejudice?" can…

  4. Empowering Young Black Males

    ERIC Educational Resources Information Center

    Kafele, Baruti K.

    2012-01-01

    Of all the challenges we face in education today, the author can think of none greater than the challenge of motivating, educating, and empowering black male learners. The fact that this group of students is in crisis is evident on multiple levels, starting with graduation rates. According to the Schott Foundation (2008), the U.S. high school…

  5. Black Phosphorus Terahertz Photodetectors.

    PubMed

    Viti, Leonardo; Hu, Jin; Coquillat, Dominique; Knap, Wojciech; Tredicucci, Alessandro; Politano, Antonio; Vitiello, Miriam Serena

    2015-10-01

    The first room-temperature terahertz (THz)-frequency nanodetector exploiting a 10 nm thick flake of exfoliated crystalline black phosphorus as an active channel of a field-effect transistor, is devised. By engineering and embedding planar THz antennas for efficient light harvesting, the first technological demonstration of a phosphorus-based active THz device is described. PMID:26270791

  6. Black Community Development.

    ERIC Educational Resources Information Center

    Harris, William M.

    This published dissertation discusses the community development process as applied to urban black ghettoes. It provides extensive documentation on the many issues, concepts, and procedures in the field of community development. The method employed in collecting the data is a through review of existing literature in the topical areas for relevance…

  7. Gasification of black liquor

    DOEpatents

    Kohl, Arthur L.

    1987-07-28

    A concentrated aqueous black liquor containing carbonaceous material and alkali metal sulfur compounds is treated in a gasifier vessel containing a relatively shallow molten salt pool at its bottom to form a combustible gas and a sulfide-rich melt. The gasifier vessel, which is preferably pressurized, has a black liquor drying zone at its upper part, a black liquor solids gasification zone located below the drying zone, and a molten salt sulfur reduction zone which comprises the molten salt pool. A first portion of an oxygen-containing gas is introduced into the gas space in the gasification zone immediatley above the molten salt pool. The remainder of the oxygen-containing gas is introduced into the molten salt pool in an amount sufficient to cause gasification of carbonaceous material entering the pool from the gasification zone but not sufficient to create oxidizing conditions in the pool. The total amount of the oxygen-containing gas introduced both above the pool and into the pool constitutes between 25 and 55% of the amount required for complete combustion of the black liquor feed. A combustible gas is withdrawn from an upper portion of the drying zone, and a melt in which the sulfur content is predominantly in the form of alkali metal sulfide is withdrawn from the molten salt sulfur reduction zone.

  8. Gasification of black liquor

    DOEpatents

    Kohl, A.L.

    1987-07-28

    A concentrated aqueous black liquor containing carbonaceous material and alkali metal sulfur compounds is treated in a gasifier vessel containing a relatively shallow molten salt pool at its bottom to form a combustible gas and a sulfide-rich melt. The gasifier vessel, which is preferably pressurized, has a black liquor drying zone at its upper part, a black liquor solids gasification zone located below the drying zone, and a molten salt sulfur reduction zone which comprises the molten salt pool. A first portion of an oxygen-containing gas is introduced into the gas space in the gasification zone immediately above the molten salt pool. The remainder of the oxygen-containing gas is introduced into the molten salt pool in an amount sufficient to cause gasification of carbonaceous material entering the pool from the gasification zone but not sufficient to create oxidizing conditions in the pool. The total amount of the oxygen-containing gas introduced both above the pool and into the pool constitutes between 25 and 55% of the amount required for complete combustion of the black liquor feed. A combustible gas is withdrawn from an upper portion of the drying zone, and a melt in which the sulfur content is predominantly in the form of alkali metal sulfide is withdrawn from the molten salt sulfur reduction zone. 2 figs.

  9. Black Literature? Of Course!

    ERIC Educational Resources Information Center

    Geyer, Donna

    1969-01-01

    The inclusion of Afro-American literature in high schools either as an elective course or as a unit within an American literature course provides opportunities for Black students to gain, from members of their own race, pride in themselves and belief in the possibility of personal achievement. Title selection should depend upon class make-up. For…

  10. Dictionary of Black Culture.

    ERIC Educational Resources Information Center

    Baskin, Wade; Runes, Richard N.

    This dictionary is an encyclopedic survey of the cultural background and development of the black American, covering the basic issues, events, contributions and biographies germane to the subject. The author-compiler is Chairman of Classical Languages Department at Southeastern State College, Durant, Oklahoma. Richard Runes is practicing law as a…

  11. Chrome alloy welding fume study.

    PubMed

    Vorpahl, K W; Jordan, P T; Mathews, E J

    1976-10-01

    Breathing zone samples obtained at a production arc welding operation employing approximately 90 welders demonstrated excessive exposure to chromium from the welding of high chromium alloy steel. Breathing zone samples were collected inside welding helmets. Methods considered for reducing employee exposure included local exhaust ventilation and the use of air-supplied helmets. Air-supplied helmets were chosen as best suited for the production scheme and suitable devices were subsequently developed that reduced breathing zone contaminant levels well below applicable standards.

  12. SETI among galaxies by virtue of black holes

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2012-09-01

    In two recent papers (Refs. Maccone (2011, 2009) [1,2]) this author proved that the radio communications among any pair of stars within our Galaxy are feasible with modest transmitted powers if the gravitational lenses of both stars are exploited. In the present paper we extend those innovative results to the case of radio communications among nearby galaxies. We show that the radio communications among galaxies may become feasible if the supermassive black holes, usually located at the center of galaxies, are exploited as gravitational lenses. In other words, a massive black hole may be regarded as a huge focusing device for radio waves being transmitted out of that galaxy and/or being received from another galaxy. This happens because a black hole is such a highly massive and compact object that all electromagnetic waves flying by its surface are highly deflected by its gravitational field and made to focus at a comparatively short distance from the black hole itself.Next we consider the possibility of building radio bridges between our own Galaxy (the Milky Way) and other nearby galaxies. This possibility is serious because, since 1974, astronomers have come to known that a supermassive black hole called Sagittarius A* does exist at the center of our Galaxy. In 2002 its mass was estimated to be of the order of 2.6 million solar masses, and in 2008 this estimate was increased to 4.31 million solar masses. Furthermore, in 2004 a team of astronomers reported the discovery of a potential intermediate-class black hole called GCIRS 13E orbiting around SgrA* at about three light-years and having an estimated mass of 1,300 solar masses. These two big black holes could be our Galaxy's “antennae” for communications with alien civilizations harboring in other nearby galaxies.We mathematically show that the following radio bridges may be created between SgrA* and the supermassive black hole located at the center of the nearby galaxies:The SgrA*-Andromeda's (M31) P2

  13. Magnetic fields during the formation of supermassive black holes

    NASA Astrophysics Data System (ADS)

    Latif, M. A.; Schleicher, D. R. G.; Schmidt, W.

    2014-05-01

    Observations of quasars at z > 6 report the existence of a billion solar mass black holes. Comprehending their formation in such a short time-scale is a matter of ongoing research. One of the most promising scenarios to assemble supermassive black holes is a monolithic collapse of protogalactic gas clouds in atomic cooling haloes with Tvir ≥ 104 K. In this paper, we study the amplification and impact of magnetic fields during the formation of seed black holes in massive primordial haloes. We perform high-resolution cosmological magnetohydrodynamic simulations for four distinct haloes and follow their collapse for a few free-fall times until the simulations reach a peak density of 7 × 10-10 g cm-3. Our findings show that irrespective of the initial seed field, the magnetic field strength reaches a saturated state in the presence of strong accretion shocks. Under such conditions, the growth time becomes very short and amplification occurs rapidly within a small fraction of the free-fall time. We find that the presence of such strong magnetic fields provides additional support against gravity and helps in suppressing fragmentation. Massive clumps of a few hundred solar masses are formed at the end of our simulations and high accretion rates of 1 M⊙ yr-1 are observed. We expect that in the presence of such accretion rates, the clumps will grow to form supermassive stars of ˜105 M⊙. Overall, the role of the magnetic fields seems supportive for the formation of massive black holes.

  14. Solar chulha

    NASA Astrophysics Data System (ADS)

    Jadhao, P. H.; Patrikar, S. R.

    2016-05-01

    The main goal of the proposed system is to transfer energy from sun to the cooking load that is located in the kitchen. The energy is first collected by the solar collector lens system and two curve bars of same radius of curvature are mounted parallel and adjacent to each other at different height the solar collector is clamed on this two bars such that solar collector is exactly perpendicular to sunlight. The topology includes an additional feature which is window in the wall through which the beam is collimated is directed in the of kitchen. The solar energy that is collected is directed by the mirror system into the kitchen, where it is redirected to cooking platform located in the kitchen. The special feature in this system full Indian meal can be made since cooking platform is indoors.

  15. Solar dryer

    SciTech Connect

    Dodelin, R.W.; Hurst, D.W.; Osos, G.R.

    1984-02-07

    Fabrics are dried by tumbling the fabrics in a drying chamber into which hot air is introduced. The hot air is formed by passing ambient air through a solar heater to heat the air to a first temperature, and then further heating the air with a second heater such as a burner. The burner can be one which burns a fuel in the presence of combustion air. The combustion air can be a portion of the air that is passed through the solar heater. After drying the fabrics by this method, the drying zone can be cooled and the fabrics can be further dried by passing air through the solar heater, and then without further heating the air that has passed through the solar heater, introducing the air to the drying chamber.

  16. Solar cell

    SciTech Connect

    Frank, R.I.; Kaplow, R.

    1980-08-26

    An improved solar cell designed for optimum efficiency is comprised of a plurality of series connected unit solar cells formed from a common substrate of semiconductor material. Each unit solar cell has spaced elongate sidewalls, and a ''dead space'' area between adjoining sidewalls of adjacent units is made substantially smaller than an active, light receiving area, extending between the opposite sidewalls of each individual unit. In addition, the width of the active area is concisely limited to ensure that radiation incident on the active area is incident at a point which is spaced from the p-n junction of each unit by no more than a predetermined optimum distance. Reducing the ''dead space'' area while concisely limiting the width of the active area provides improved solar cell performance without requiring focusing lenses.

  17. Solar Energy

    ERIC Educational Resources Information Center

    Building Design and Construction, 1977

    1977-01-01

    Describes 21 completed projects now using solar energy for heating, cooling, or electricity. Included are elementary schools in Atlanta and San Diego, a technical school in Detroit, and Trinity University in San Antonio, Texas. (MLF)

  18. Solar Nexus.

    ERIC Educational Resources Information Center

    Murphy, Jim

    1980-01-01

    The design team for the Solar Energy Research Institute (SERI) has pushed the state of the energy art to its current limits for the initial phase, with provisions for foreseeable and even speculative future applications. (Author/MLF)

  19. "Survivor" Black Holes May Be Mid-Sized

    NASA Astrophysics Data System (ADS)

    2010-04-01

    New evidence from NASA's Chandra X-ray Observatory and ESA's XMM-Newton strengthens the case that two mid-sized black holes exist close to the center of a nearby starburst galaxy. These "survivor" black holes avoided falling into the center of the galaxy and could be examples of the seeds required for the growth of supermassive black holes in galaxies, including the one in the Milky Way. For several decades, scientists have had strong evidence for two distinct classes of black hole: the stellar-mass variety with masses about ten times that of the Sun, and the supermassive ones, located at the center of galaxies, that range from hundreds of thousands to billions of solar masses. But a mystery has remained: what about black holes that are in between? Evidence for these objects has remained controversial, and until now there were no strong claims of more than one such black hole in a single galaxy. Recently, a team of researchers has found signatures in X-ray data of two mid-sized black holes in the starburst galaxy M82 located 12 million light years from Earth. "This is the first time that good evidence for two mid-sized black holes has been found in one galaxy," said Hua Feng of the Tsinghua University in China, who led two papers describing the results. "Their location near the center of the galaxy might provide clues about the origin of the Universe's largest black holes - supermassive black holes found in the centers of most galaxies." One possible mechanism for the formation of supermassive black holes involves a chain reaction of collisions of stars in compact star clusters that results in the buildup of extremely massive stars, which then collapse to form intermediate-mass black holes. The star clusters then sink to the center of the galaxy, where the intermediate-mass black holes merge to form a supermassive black hole. In this picture, clusters that were not massive enough or close enough to the center of the galaxy to fall in would survive, as would any

  20. Growth of Primordial Black Holes

    NASA Astrophysics Data System (ADS)

    Harada, Tomohiro

    Primordial black holes have important observational implications through Hawking evaporation and gravitational radiation as well as being a candidate for cold dark matter. Those black holes are assumed to have formed in the early universe typically with the mass scale contained within the Hubble horizon at the formation epoch and subsequently accreted mass surrounding them. Numerical relativity simulation shows that primordial black holes of different masses do not accrete much, which contrasts with a simplistic Newtonian argument. We see that primordial black holes larger than the 'super-horizon' primordial black holes have decreasing energy and worm-hole like struture, suggesting the formation through quamtum processes.