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Sample records for hard infrared black

  1. Hard, infrared black coating with very low outgassing

    SciTech Connect

    Kuzmenko, P J; Behne, D M; Casserly, T; Boardman, W; Upadhyaya, D; Boinapally, K; Gupta, M; Cao, Y

    2008-06-02

    Infrared astronomical instruments require absorptive coatings on internal surfaces to trap scattered and stray photons. This is typically accomplished with any one of a number of black paints. Although inexpensive and simple to apply, paint has several disadvantages. Painted surfaces can be fragile, prone to shedding particles, and difficult to clean. Most importantly, the vacuum performance is poor. Recently a plasma enhanced chemical vapor deposition (PECVD) process was developed to apply thick (30 {micro}m) diamond-like carbon (DLC) based protective coatings to the interior of oil pipelines. These DLC coatings show much promise as an infrared black for an ultra high vacuum environment. The coatings are very robust with excellent cryogenic adhesion. Their total infrared reflectivity of < 10% at normal incidence approaches that of black paints. We measured outgas rates of <10{sup -12} Torr liter/sec cm{sup 2}, comparable to bare stainless steel.

  2. Dressed Hard States and Black Hole Soft Hair

    NASA Astrophysics Data System (ADS)

    Mirbabayi, Mehrdad; Porrati, Massimo

    2016-11-01

    A recent, intriguing Letter by Hawking, Perry, and Strominger suggests that soft photons and gravitons can be regarded as black hole hair and may be relevant to the black hole information paradox. In this Letter we make use of factorization theorems for infrared divergences of the S matrix to argue that by appropriately dressing in and out hard states, the soft-quanta-dependent part of the S matrix becomes essentially trivial. The information paradox can be fully formulated in terms of dressed hard states, which do not depend on soft quanta.

  3. Dressed Hard States and Black Hole Soft Hair.

    PubMed

    Mirbabayi, Mehrdad; Porrati, Massimo

    2016-11-18

    A recent, intriguing Letter by Hawking, Perry, and Strominger suggests that soft photons and gravitons can be regarded as black hole hair and may be relevant to the black hole information paradox. In this Letter we make use of factorization theorems for infrared divergences of the S matrix to argue that by appropriately dressing in and out hard states, the soft-quanta-dependent part of the S matrix becomes essentially trivial. The information paradox can be fully formulated in terms of dressed hard states, which do not depend on soft quanta.

  4. Black phosphorus mid-infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Xu, Mei; Gu, Yuqian; Peng, Ruoming; Youngblood, Nathan; Li, Mo

    2017-04-01

    Few-layer black phosphorus (BP) has emerged as a promising 2D material for photodetection in the mid-infrared spectral range given its narrow bandgap. However, a comprehensive understanding of BP photodetector's response in the mid-infrared is still lacking. In this paper, we study the photoresponse of few-layer BP photodetector in the mid-infrared range from 2.5 to 3.7 µm. We identify broadband photoresponse of BP photodetectors in the mid-infrared and observe saturation of the response with optical power. Through frequency and time domain measurements, we have also identified the two dominate mechanisms in our device to be due to the photovoltaic and photogating effects. Our results provide valuable information for optimization of BP mid-infrared photodetectors toward rivaling the current infrared photodetection technology based on compound semiconductors.

  5. Advanced infrared optically black baffle materials

    SciTech Connect

    Seals, R.D.; Egert, C.M. ); Allred, D.D. . Dept. of Physics and Astronomy)

    1990-01-01

    Infrared optically black baffle surfaces are an essential component of many advanced optical systems. All internal surfaces in advanced infrared optical sensors that require stray light management to achieve resolution are of primary concern in baffle design. Current industrial materials need improvements to meet advanced optical sensor systems requirements for optical, survivability, and endurability. Baffles are required to survive and operate in potentially severe environments. Robust diffuse-absorptive black surfaces, which are (1) thermally and mechanically stable to threats of x-ray, launch, and in-flight maneuver conditions, with specific densities to allow an acceptable weight load, (2) handleable during assembly, (3) cleanable, and (4) adaptive to affordable manufacturing, are required as optical baffle materials. In this paper an overview of recently developed advanced infrared optical baffle materials, requirements, manufacturing strategies, and the Optics MODIL (Manufacturing Operations Development and Integration Laboratory) Advanced Baffle Program will be discussed. 11 refs., 15 figs., 2 tabs.

  6. MODELING THE HARD STATES OF THREE BLACK HOLE CANDIDATES

    SciTech Connect

    Zhang Hui; Yuan Feng; Chaty, Sylvain

    2010-07-10

    Simultaneous multiwavelength observations were recently performed for three black hole candidates-SWIFT J1753.5-0127, GRO J1655-40, and XTE J1720-318. In this paper, we test the accretion-jet model originally proposed for XTE J1118+480 by investigating the hard state of these three sources using this model. The accretion flow in the model is composed of an inner hot accretion flow and an outer truncated thin disk. We find that the model satisfactorily explains the spectrum ranging from radio to X-rays, with the radio and X-ray spectra dominated by the synchrotron and thermal Comptonization emissions in the jet and the hot accretion flow, respectively, with the infrared and optical being the sum of the emissions from the jet, hot accretion flow, and the truncated thin disk. Similar to the case of XTE J1118+480, the model can also explain, although only qualitatively in some cases, the observed timing features including quasi-periodic oscillation, and positive and negative time lags between the optical and X-ray emissions detected in SWIFT J1753.5-0127. The origin of the ejection events detected in XTE J1720-318 is also briefly discussed.

  7. A Universal Definition and Categorization of Black Holes Hardness States:

    NASA Astrophysics Data System (ADS)

    Filothodoros, Alexandros

    2016-07-01

    We show our progress in using a method that will categorize the hardness states of accreting black holes, regardless of the instrument used. We use all the public data available from MAXI, SWIFT/BAT , RXTE and XMM-NEWTON and focus mostly on the almost simultaneous data.

  8. Moisture influence on near-infrared prediction of wheat hardness

    NASA Astrophysics Data System (ADS)

    Windham, William R.; Gaines, Charles S.; Leffler, Richard G.

    1991-02-01

    Recently near infrared (NTR) reflectance instrumentation has been used to provide an empirical measure of wheat hardness. This hardness scale is based on the radiation scattering properties of meal particles at 1680 and 2230 nm. Hard wheats have a larger mean particles size (PS) after grinding than soft wheats. However wheat kernel moisture content can influence mean PS after grinding. The objective of this study was to determine the sensitivity of MR wheat hardness measurements to moisture content and to make the hardness score independent of moisture by correcting hardness measurements for the actual moisture content of measured samples. Forty wheat cultivars composed of hard red winter hard red spring soft red winter and soft white winter were used. Wheat kernel subsamples were stored at 20 40 60 and 80 relative humidity (RH). After equilibration samples were ground and the meal analyzed for hardness score (HS) and moisture. HS were 48 50 54 and 65 for 20 40 60 and 80 RH respectively. Differences in HS within each wheat class were the result of a moisture induced change in the PS of the meal. An algorithm was developed to correct HS to 11 moisture. This correction provides HS that are nearly independent of moisture content. 1.

  9. Hard X-ray observations of ultraluminous infrared galaxies

    NASA Technical Reports Server (NTRS)

    Rieke, G. H.

    1988-01-01

    X-ray flux upper limits of 2-10 keV for ultraluminous infrared galaxies were drawn from the HEAO A-1 data base. The hard X-ray luminosities of these sources are much weaker relative to their total luminosities than would be expected for Seyfert 1 galaxies or quasi-stellar objects. Because of the low level of interstellar extinction for hard X-rays, this result suggests that the ultraluminous galaxies are not powered by embedded QSOs that are otherwise similar to other QSOs. Three other possibilities are: (1) the infrared galaxies may contain a form of X-ray-quiet active nucleus; (2) the X-ray sources in active nuclei may not turn on until after the circumnuclear gas has cleared; or (3) the bulk of the infrared luminosity in these galaxies may be generated by intense circumnuclear star formation.

  10. Hard X-ray observations of ultraluminous infrared galaxies

    SciTech Connect

    Rieke, G.H.

    1988-08-01

    X-ray flux upper limits of 2-10 keV for ultraluminous infrared galaxies were drawn from the HEAO A-1 data base. The hard X-ray luminosities of these sources are much weaker relative to their total luminosities than would be expected for Seyfert 1 galaxies or quasi-stellar objects. Because of the low level of interstellar extinction for hard X-rays, this result suggests that the ultraluminous galaxies are not powered by embedded QSOs that are otherwise similar to other QSOs. Three other possibilities are: (1) the infrared galaxies may contain a form of X-ray-quiet active nucleus; (2) the X-ray sources in active nuclei may not turn on until after the circumnuclear gas has cleared; or (3) the bulk of the infrared luminosity in these galaxies may be generated by intense circumnuclear star formation. 27 references.

  11. Radiation hardness by design for mixed signal infrared readout circuit applications

    NASA Astrophysics Data System (ADS)

    Gaalema, Stephen; Gates, James; Dobyns, David; Pauls, Greg; Wall, Bruce

    2013-09-01

    Readout integrated circuits (ROICs) to support space-based infrared detection applications often have severe radiation tolerance requirements. Radiation hardness-by-design (RHBD) significantly enhances the radiation tolerance of commercially available CMOS and custom radiation hardened fabrication techniques are not required. The combination of application specific design techniques, enclosed gate architecture nFETs and intrinsic thin oxide radiation hardness of 180 nm process node commercial CMOS allows realization of high performance mixed signal circuits. Black Forest Engineering has used RHBD techniques to develop ROICs with integrated A/D conversion that operate over a wide range of temperatures (40K-300K) to support infrared detection. ROIC radiation tolerance capability for 256x256 LWIR area arrays and 1x128 thermopile linear arrays is presented. The use of 130 nm CMOS for future ROIC RHBD applications is discussed.

  12. Infrared Spectroscopy of Black Hole Candidates

    NASA Technical Reports Server (NTRS)

    Colgan, Sean W.; Cotera, A. S.; Maloney, P. R.; Hollenbach, D. J.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    ISO LWS and SWS observations of the approx. 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 et al. (1997, ApJ482, L41) have predicted that detectable far-infrared line emission from [0I] (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 et al.to constrain the properties of the ISM in the vicinity of these X-ray sources.

  13. Infrared Spectroscopy of Black Hole Candidates

    NASA Technical Reports Server (NTRS)

    Colgan, Sean W.; Cotera, A. S.; Maloney, P. R.; Hollenbach, D. J.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    ISO LWS and SWS observations of the approx. 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 et al. (1997, ApJ482, L41) have predicted that detectable far-infrared line emission from [0I] (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 et al.to constrain the properties of the ISM in the vicinity of these X-ray sources.

  14. Galactic Black Holes in the Hard State: A Multi-Wavelength View of Accretion and Ejection

    NASA Technical Reports Server (NTRS)

    Kalemci; Tomsick, John A.; Migliari; Corbel; Markoff

    2010-01-01

    The canonical hard state is associated with emission from all three fundamental accretion components: the accretion disk, the hot accretion disk corona and the jet. On top of these, the hard state also hosts very rich temporal variability properties (low frequency QPOs in the PDS, time lags, long time scale evolution). Our group has been working on the major questions of the hard state both observationally (with mult i-wavelength campaigns using RXTE, Swift, Suzaku, Spitzer, VLA, ATCA, SMARTS) and theoretically (through jet models that can fit entire SEDs). Through spectral and temporal analysis we seek to determine the geometry of accretion components, and relate the geometry to the formation and emission from a jet. In this presentation I will review the recent contributions of our group to the field, including the Swift results on the disk geometry at low accretion rates, the jet model fits to the hard state SEDs (including Spitzer data) of GRO J1655-40, and the final results on the evolution of spectral (including X-ray, radio and infrared) and temporal properties of elected black holes in the hard states. I will also talk about impact of ASTROSAT to the science objective of our group.

  15. Galactic Black Holes in the Hard State: A Multi-Wavelength View of Accretion and Ejection

    NASA Technical Reports Server (NTRS)

    Kalemci; Tomsick, John A.; Migliari; Corbel; Markoff

    2010-01-01

    The canonical hard state is associated with emission from all three fundamental accretion components: the accretion disk, the hot accretion disk corona and the jet. On top of these, the hard state also hosts very rich temporal variability properties (low frequency QPOs in the PDS, time lags, long time scale evolution). Our group has been working on the major questions of the hard state both observationally (with mult i-wavelength campaigns using RXTE, Swift, Suzaku, Spitzer, VLA, ATCA, SMARTS) and theoretically (through jet models that can fit entire SEDs). Through spectral and temporal analysis we seek to determine the geometry of accretion components, and relate the geometry to the formation and emission from a jet. In this presentation I will review the recent contributions of our group to the field, including the Swift results on the disk geometry at low accretion rates, the jet model fits to the hard state SEDs (including Spitzer data) of GRO J1655-40, and the final results on the evolution of spectral (including X-ray, radio and infrared) and temporal properties of elected black holes in the hard states. I will also talk about impact of ASTROSAT to the science objective of our group.

  16. Absorption of infrared radiation by human dental hard substances

    NASA Astrophysics Data System (ADS)

    Roth, Klaus K.; Duczynski, Edwin W.; von der Heide, Hans-Joachim; Struve, Bert

    1993-12-01

    Absorption spectra of enamel, dentin, synthetic hydroxyapatite and deionized water were taken in the wavelength band 500 to 3000 nm. It could be shown that infrared radiation is mainly absorbed in the aqueous components of dental hard tissues. Because of their decreased water content extinctions measured are slightly lower than those of deionized water. Furthermore, mineral absorptions could be detected in the range of 2760 to 2840 nm with a maximum at 2800 nm in enamel and a smaller one at 2500 nm in dentin.

  17. Cryogenic emissivity properties of Ball Infrared Black

    NASA Astrophysics Data System (ADS)

    Franck, Randy; Renbarger, Michael

    2012-06-01

    Ball Aerospace and Technologies Corporation (BATC) developed a unique thermal control coating named Ball InfraRed BlackTM (BIRBTM). The coating generates a highly diffuse surface with a large effective surface area ideal for thermal radiative applications. Independent testing demonstrates excellent emissivity properties across the cryogenic region, especially at temperatures <50K where other products tend to roll off. Emissivity in this region exceeds that of other commercially available thermal control coatings. The proprietary coating was developed for use on spacecraft thermal radiators, but also has application to terrestrial cryogenic and vacuum systems. The coating is qualified for spaceflight, demonstrating outstanding adhesion after thermal cycling and vibration testing. Critical material properties for BIRBTM are characterized. BIRBTM is durable and cleanable with proper handling. BIRBTM has the additional benefit of being static-dissipative, making it ideal for direct exposure to the space environment. Additionally, contamination control properties are optimized, achieving low total outgassing rates and demonstrating particle cleanliness to meet stringent requirements for optical instruments. Thermal systems realize enhanced performance and/or substantial mass savings by applying BIRBTM to the radiator surface. To date, BIRBTM has been applied to several large cryogenic radiators for use on space-based thermal control systems.

  18. Infrared fingerprints of few-layer black phosphorus.

    PubMed

    Zhang, Guowei; Huang, Shenyang; Chaves, Andrey; Song, Chaoyu; Özçelik, V Ongun; Low, Tony; Yan, Hugen

    2017-01-06

    Black phosphorus is an infrared layered material. Its bandgap complements other widely studied two-dimensional materials: zero-gap graphene and visible/near-infrared gap transition metal dichalcogenides. Although highly desirable, a comprehensive infrared characterization is still lacking. Here we report a systematic infrared study of mechanically exfoliated few-layer black phosphorus, with thickness ranging from 2 to 15 layers and photon energy spanning from 0.25 to 1.36 eV. Each few-layer black phosphorus exhibits a thickness-dependent unique infrared spectrum with a series of absorption resonances, which reveals the underlying electronic structure evolution and serves as its infrared fingerprints. Surprisingly, unexpected absorption features, which are associated with the forbidden optical transitions, have been observed. Furthermore, we unambiguously demonstrate that controllable uniaxial strain can be used as a convenient and effective approach to tune the electronic structure of few-layer black phosphorus. Our study paves the way for black phosphorus applications in infrared photonics and optoelectronics.

  19. Infrared fingerprints of few-layer black phosphorus

    NASA Astrophysics Data System (ADS)

    Zhang, Guowei; Huang, Shenyang; Chaves, Andrey; Song, Chaoyu; Özçelik, V. Ongun; Low, Tony; Yan, Hugen

    2017-01-01

    Black phosphorus is an infrared layered material. Its bandgap complements other widely studied two-dimensional materials: zero-gap graphene and visible/near-infrared gap transition metal dichalcogenides. Although highly desirable, a comprehensive infrared characterization is still lacking. Here we report a systematic infrared study of mechanically exfoliated few-layer black phosphorus, with thickness ranging from 2 to 15 layers and photon energy spanning from 0.25 to 1.36 eV. Each few-layer black phosphorus exhibits a thickness-dependent unique infrared spectrum with a series of absorption resonances, which reveals the underlying electronic structure evolution and serves as its infrared fingerprints. Surprisingly, unexpected absorption features, which are associated with the forbidden optical transitions, have been observed. Furthermore, we unambiguously demonstrate that controllable uniaxial strain can be used as a convenient and effective approach to tune the electronic structure of few-layer black phosphorus. Our study paves the way for black phosphorus applications in infrared photonics and optoelectronics.

  20. Infrared fingerprints of few-layer black phosphorus

    PubMed Central

    Zhang, Guowei; Huang, Shenyang; Chaves, Andrey; Song, Chaoyu; Özçelik, V. Ongun; Low, Tony; Yan, Hugen

    2017-01-01

    Black phosphorus is an infrared layered material. Its bandgap complements other widely studied two-dimensional materials: zero-gap graphene and visible/near-infrared gap transition metal dichalcogenides. Although highly desirable, a comprehensive infrared characterization is still lacking. Here we report a systematic infrared study of mechanically exfoliated few-layer black phosphorus, with thickness ranging from 2 to 15 layers and photon energy spanning from 0.25 to 1.36 eV. Each few-layer black phosphorus exhibits a thickness-dependent unique infrared spectrum with a series of absorption resonances, which reveals the underlying electronic structure evolution and serves as its infrared fingerprints. Surprisingly, unexpected absorption features, which are associated with the forbidden optical transitions, have been observed. Furthermore, we unambiguously demonstrate that controllable uniaxial strain can be used as a convenient and effective approach to tune the electronic structure of few-layer black phosphorus. Our study paves the way for black phosphorus applications in infrared photonics and optoelectronics. PMID:28059084

  1. 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.

  2. Azimuthal asymmetries in QCD hard scattering: infrared safe but divergent

    NASA Astrophysics Data System (ADS)

    Catani, Stefano; Grazzini, Massimiliano; Sargsyan, Hayk

    2017-06-01

    We consider high-mass systems of two or more particles that are produced by QCD hard scattering in hadronic collisions. We examine the azimuthal correlations between the system and one of its particles. We point out that the perturbative QCD computation of such azimuthal correlations and asymmetries can lead to divergent results at fixed perturbative orders. The fixed-order divergences affect basic (and infrared safe) quantities such as the total cross section at fixed (and arbitrary) values of the azimuthal-correlation angle φ. Examples of processes with fixed-order divergences are heavy-quark pair production, associated production of vector bosons and jets, dijet and diboson production. A noticeable exception is the production of high-mass lepton pairs through the Drell-Yan mechanism of quark-antiquark annihilation. However, even in the Drell-Yan process, fixed-order divergences arise in the computation of QED radiative corrections. We specify general conditions that produce the divergences by discussing their physical origin in fixed-order computations. We show lowest-order illustrative results for cos( nφ) asymmetries (with n = 1 , 2 , 4 , 6) in top-quark pair production and associated production of a vector boson and a jet at the LHC. The divergences are removed by a proper all-order resummation procedure of the perturbative contributions. Resummation leads to azimuthal asymmetries that are finite and computable. We present first quantitative results of such a resummed computation for the cos(2 φ) asymmetry in top-quark pair production at the LHC.

  3. [Identification of hardness of licorice single seed using near infrared spectroscopy].

    PubMed

    Sun, Qun; Li, Jun-Hui; Wang, Jian-Hua; Sun, Bao-Qi

    2009-10-01

    To break the dilemma on judging hard seeds and soft seeds of licorice and other legume families nondestructively, a distinguishing model for the hardness of licorice single seed was tried to be built by near infrared reflectance spectroscopy with distinguished partial least squares(DPLS). A total of 244 licorice seeds were divided into three groups: calibration set (120 samples), validation set (60 samples) and prediction set (64 samples), and each group has the same number of hard seeds and soft seeds. To eliminate the human error as far as possible, a specially made sample cup was designed for spectrum acquisition. Then the locations of the seed and the fiber-optic probe were fixed during each spectrum acquisition process. The influences of different replicate time, different spectral region and different calibration samples on the identification rate were compared. The result indicated that four replicates could increase the identification rate of the model significantly, the identification rates of the model of four replicates in calibration, validation and prediction set samples were 95.83%, 95.00% and 96.88% respectively, while that of one replicate were 93.33%, 91.67% and 82.81% respectively. The model of the spectral region between 4,000 and 80,000 cm(-1) was better than that of other regions, and the identification rate in calibration, validation and prediction set samples were 95.53%, 95.94% and 94.53% respectively. Even with different samples, the predication rates were all more than 90%. The identification rates of hard seed and soft seed in prediction set samples were 92.50% and 96.56% respectively. The prediction for seeds with different size and different color showed that this model was not suitable for bigger and smaller seeds, especially not for black seeds. NIR offered a new way to distinguish the hardness of licorice singe seed quickly, precisely and nondestructively, which will advance the study on the mechanism of hardness of crop seeds.

  4. Mid-infrared time-resolved photoconduction in black phosphorus

    NASA Astrophysics Data System (ADS)

    Suess, Ryan J.; Leong, Edward; Garrett, Joseph L.; Zhou, Tong; Salem, Reza; Munday, Jeremy N.; Murphy, Thomas E.; Mittendorff, Martin

    2016-12-01

    Black phosphorus has attracted interest as a material for use in optoelectronic devices due to many favorable properties such as a high carrier mobility, field-effect, and a direct bandgap that can range from 0.3 eV in its bulk crystalline form to 1.7-2.0 eV for a single atomic layer. The low bandgap energy for multilayer black phosphorus consisting of more than approximately five atomic layers allows for direct transition photoabsorption that enables detection of light out to mid-infrared frequencies. In this work, we characterize the room temperature optical response of a black phosphorus photoconductive detector at wavelengths ranging from 1.56 to 3.75 μm. Pulsed autocorrelation measurements in the near-infrared regime reveal a strong, sub-linear photocurrent nonlinearity with a response time of 1 ns, indicating that gigahertz electrical bandwidth is feasible. Time resolved photoconduction measurements covering near- and mid-infrared frequencies show a fast 65 ps rise time, followed by a carrier relaxation with a time scale that matches the intrinsic limit determined by autocorrelation. The sublinear photoresponse is shown to be caused by a reduction in the carrier relaxation time as more energy is absorbed in the black phosphorus flake and is well described by a carrier recombination model that is nonlinear with excess carrier density. The device exhibits a measured noise-equivalent power of 530 pW Hz-1/2, which is the value expected for Johnson noise limited performance. The fast and sensitive room temperature photoresponse demonstrates that black phosphorus is a promising new material for mid-infrared optoelectronics.

  5. Infrared and colorimetric characterization of discolored kiln-dried hard maple lumber

    Treesearch

    Benjamin E. Dawson-Andoh; Michael Wiemann; Laurent Matuana; John Baumgras

    2004-01-01

    Discoloration of hard maple lumber commonly occurs during kiln-drying. In this study, discolored andnondiscolored kiln-dried hard maple lumber boards were characterized using a colorimetric method and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). Colorimetric measurements (L*, a*, b*) were found to be in good agreement with visual...

  6. Black surfaces for infrared, aerospace, and cryogenic applications

    NASA Astrophysics Data System (ADS)

    Kralik, Tomas; Katsir, Dina

    2009-05-01

    Coatings with high absorption or emission of thermal radiation are often required in infrared, space and cryogenic applications. It is much more difficult to generate a surface which is sufficiently "black" at cryogenic temperatures than at room or elevated temperatures. An experimental study was carried out to compare the thermal emissivity and absorptivity of a variety of black coatings on copper and aluminum substrates at temperatures in the range from 10 K to 300 K and the results are presented in this paper. The surfaces tested include paints and thin-film coatings.

  7. Self-organized, effective medium Black Silicon for infrared antireflection

    NASA Astrophysics Data System (ADS)

    Steglich, Martin; Käsebier, Thomas; Schrempel, Frank; Kley, Ernst-Bernhard; Tünnermann, Andreas

    2015-03-01

    Statistical Black Silicon antireflection structures for the mid-infrared spectral region, fabricated by Inductively Coupled Plasma Reactive Ion Etching, are investigated. Upon variation of etch duration scaling of the structure morphologies is observed and related to the optical losses in specular transmittance. By means of statistical morphology analysis, an effective medium criterion for the examined structures is derived that can be used as a design rule for maximizing sample transmittance at a given wavelength. To obtain Black Silicon antireflection structures with elevated bandwidth, an additional deep-etch step is proposed and demonstrated.

  8. Powerful jets from black hole X-ray binaries in low/hard X-ray states

    NASA Astrophysics Data System (ADS)

    Fender, R. P.

    2001-03-01

    Four persistent (Cygnus X-1, GX 339-4, GRS 1758-258 and 1E 1740.7-2942) and three transient (GS 2023+38, GRO J0422+32 and GS 1354-64) black hole X-ray binary systems have been extensively observed at radio wavelengths during extended periods in the low/hard X-ray state, which is characterized in X-rays by a hard power-law spectrum and strong variability. All seven systems show a persistent flat or inverted (in the sense that α>~0, where Sν~να) radio spectrum in this state, markedly different from the optically thin radio spectra exhibited by most X-ray transients within days of outburst. Furthermore, in none of the systems is a high-frequency cut-off to this spectral component detected, and there is evidence that it extends to near-infrared or optical regimes. Luminous persistent hard X-ray states in the black hole system GRS 1915+105 produce a comparable spectrum. This spectral component is considered to arise in synchrotron emission from a conical, partially self-absorbed jet, of the same genre as those originally considered for active galactic nuclei. Whatever the physical origin of the low/hard X-ray states, these self-similar outflows are an ever-present feature. The power in the jet component is likely to be a significant (>=5per cent) and approximately fixed fraction of the total accretion luminosity. The correlation between hard X-ray and synchrotron emission in all the sources implies that the jets are intimately related to the Comptonization process, and do not have very large bulk Lorentz factors, unless the hard X-ray emission is also beamed by the same factor.

  9. Infrared sensor with precisely patterned Au black absorption layer

    NASA Astrophysics Data System (ADS)

    Hirota, Masaki; Morita, Shinichi

    1998-10-01

    Thermoelectric infrared sensors has been fabricated by adding to the CMOS process a surface micromachining technique and a highly accurate process for forming an infrared radiation absorbing layer. The sensor, or thermopile, consists of alternating areas of p-type and n-type polysilicon connected in series on a Si3N4 layer. An anisotropic etching technique using hydrazine is employed to form a thermally isolated membrane. While a Au-black layer for infrared radiation absorption provides the best absorption efficiency over a broad infrared wavelength region, it has been difficult to pattern the layer precisely. Patterning is accomplished by forming the Au-black layer by a low-pressure vapor deposition technique on amorphous Si and a PSG sacrificial layer and then removing it on PSG by the lift-off technique or wet etching PSG. This technique makes it possible to obtain a Au-black pattern with the same degree of accuracy as with the CMOS process. As a result, sensor performance has been improved and a device array has also been achieved. A simple sensor design method has been established by which simulations are easily conducted using a thermal equivalent circuit based on the CMOS process. Prototype sensors, having external dimensions of 160 micrometer X 160 micrometer, achieved responsivity of 300, 149 and 60 V/W and a time constant of 2.0, 0.46 and 0.27 msec in the air, respectively. These performance figures surpass the performance reported to date for thermoelectric infrared sensors.

  10. Infrared Echoes of a Black Hole Eating a Star Illustration

    NASA Image and Video Library

    2016-09-15

    This illustration shows a glowing stream of material from a star as it is being devoured by a supermassive black hole in a tidal disruption flare. When a star passes within a certain distance of a black hole -- close enough to be gravitationally disrupted -- the stellar material gets stretched and compressed as it falls into the black hole. In the process of being accreted, the gas heats up and creates a lot of optical and ultraviolet light, which destroys nearby dust but merely heats dust further out. The farther dust that is heated emits a large amount of infrared light. In recent years, a few dozen such flares have been discovered, but they are not well understood. Astronomers gained new insights into tidal disruption flares thanks to data from NASA's Wide-field Infrared Survey Explorer (WISE). Studies using WISE data characterized tidal disruption flares by studying how surrounding dust absorbs and re-emits their light, like echoes. This approach allowed scientists to measure the energy of flares from stellar tidal disruption events more precisely than ever before. http://photojournal.jpl.nasa.gov/catalog/PIA20027

  11. Measuring black carbon spectral extinction in the visible and infrared

    NASA Astrophysics Data System (ADS)

    Smith, A. J. A.; Peters, D. M.; McPheat, R.; Lukanihins, S.; Grainger, R. G.

    2015-09-01

    This work presents measurements of the spectral extinction of black carbon aerosol from 400 nm to 15 μm. The aerosol was generated using a Miniature Combustion Aerosol Standard soot generator and then allowed to circulate in an aerosol cell where its extinction was measured using a grating spectrometer in the visible and a Fourier transform spectrometer in the infrared. Size distribution, number concentration, and mass extinction cross sections have also been obtained using single-particle aerosol samplers. A mean mass extinction cross section at 550 nm of 8.3 ± 1.6 m2 g-1 is found which, assuming a reasonable single scatter albedo of 0.2, corresponds to a mass absorption cross section of 6.6 ± 1.3 m2 g-1. This compares well with previously reported literature values. Computer analysis of electron microscope images of the particles provides independent confirmation of the size distribution as well as fractal parameters of the black carbon aerosol. The aerosol properties presented in this work are representative of very fresh, uncoated black carbon aerosol. After atmospheric processing of such aerosols (which could include mixing with other constituents and structural changes), different optical properties would be expected.

  12. Adolescent Black Holes May be Hard to Find

    NASA Astrophysics Data System (ADS)

    Elvis, Martin; Chakravorty, Susmita

    2017-08-01

    Finding adolescent black holes that are growing rapidly from their seed masses is a major goal of the next generation of large observatories. We have examined how these early quasars may appear in terms of their broad emission lines (BELs) in the optical and ultraviolet. We find that below 10**6 Msol, the equivalent widths of the BELs drop precipitously. Moreover, if the BELs originate in clouds that form as the cool phase of a multi-phase medium, then for metallicities Z/Zsol ~< 3, the thermal instabilities that create them will not exist. However, in observed quasars at high redshift Z/Zsol is >> 3, so quasars are preferentially found in special environments, perhaps with deep potential wells. The population that we see though could be biased by the Z/Zsol > 3 requirement. A stronger argument is that the thermal instability leading to cool clouds is predominantly due to line emission by iron. Iron comes primarily from type 1a supernovae, which take of order 1 billion years to ignite. Hence iron should be under-abundant relative to other elements until z ~ 6 - 7. That the highest redshift quasar is at z = 7.1 may be a consequence of this requirement. Quasars above z ~ 7 could still be found by their rest-frame ultraviolet or X-ray continuum.

  13. Infrared identification of hard X-ray sources in the Galaxy

    NASA Astrophysics Data System (ADS)

    Nebot Gómez-Morán, A.; Motch, C.; Pineau, F.-X.; Carrera, F. J.; Pakull, M. W.; Riddick, F.

    2015-09-01

    The nature of the low- to intermediate-luminosity (LX ˜ 1032-34 erg s-1) source population revealed in hard band (2-10 keV) X-ray surveys of the Galactic plane is poorly understood. To overcome such problem, we cross-correlated the XMM-Newton 3XMM-DR4 survey with the infrared Two Micron All Sky Survey and Galactic Legacy Infrared Mid-Plane Survey Extraordinaire catalogues. We identified reliable X-ray-infrared associations for 690 sources. We selected 173 sources having hard X-ray spectra, typical of hard X-ray high-mass stars (kT > 5 keV), and 517 sources having soft X-ray spectra, typical of active coronae. About 18 per cent of the soft sources are classified in the literature: ˜91 per cent as stars, with a minor fraction of Wolf-Rayet (WR) stars. Roughly 15 per cent of the hard sources are classified in the literature: ˜68 per cent as high-mass X-ray stars single or in binary systems (WR, Be and high-mass X-ray binaries - HMXBs), with a small fraction of G and B stars. We carried out infrared spectroscopic pilot observations at the William Herschel Telescope for five hard X-ray sources. Three of them are high-mass stars with spectral types WN7-8h, Ofpe/WN9 and Be, and LX ˜ 1032-1033erg s-1. One source is a colliding-wind binary, while another source is a colliding-wind binary or a supergiant fast X-ray transient in quiescence. The Be star is a likely γ-Cas system. The nature of the other two X-ray sources is uncertain. The distribution of hard X-ray sources in the parameter space made of X-ray hardness ratio, infrared colours and X-ray-to-infrared flux ratio suggests that many of the unidentified sources are new γ-Cas analogues, WRs and low LX HMXBs. However, the nature of the X-ray population with Ks ≥ 11 and average X-ray-to-infrared flux ratio remains unconstrained.

  14. [Determination of Hard Rate of Alfalfa (Medicago sativa L.) Seeds with Near Infrared Spectroscopy].

    PubMed

    Wang, Xin-xun; Chen, Ling-ling; Zhang, Yun-wei; Mao, Pei-sheng

    2016-03-01

    Alfalfa (Medicago sativa L.) is the most commonly grown forage crop due to its better quality characteristics and high adaptability in China. However, there was 20%-80% hard seeds in alfalfa which could not be identified easily from non hard seeds which would cause the loss of seed utilization value and plant production. This experiment was designed for 121 samples of alfalfa. Seeds were collected according to different regions, harvested year and varieties. 31 samples were artificial matched as hard rates ranging from 20% to 80% to establish a model for hard seed rate by near infrared spectroscopy (NIRS) with Partial Least Square (PLS). The objective of this study was to establish a model and to estimate the efficiency of NIRS for determining hard rate of alfalfa seeds. The results showed that the correlation coefficient (R2(cal)) of calibration model was 0.981 6, root mean square error of cross validation (RMSECV) was 5.32, and the ratio of prediction to deviation (RPD) was 3.58. The forecast model in this experiment presented the satisfied precision. The proposed method using NIRS technology is feasible for identification and classification of hard seed in alfalfa. A new method, as nondestructive testing of hard seed rate, was provided to theoretical basis for fast nondestructive detection of hard seed rates in alfalfa.

  15. An Infrared Search for Binary Companions to White Dwarfs with Hard X-Ray Emission

    NASA Astrophysics Data System (ADS)

    O'Dwyer, Ian J.; Gruendl, Robert; Chu, You-Hua; Guerrero, Martin A.

    2002-08-01

    A white dwarf (WD) can emit soft (≪ 0.4 keV) X-rays, if it is hot enough, i.e., T_eff > 30,000 K for a pure hydrogen atmosphere or T_eff > 100,000 K for a hydrogen and helium atmosphere. A WD can also emit harder (> 0.5 keV) X-rays, if it has a close binary companion and mass transfer takes place, e.g., dwarf novae, polars, and cataclysmic variables. We found a large number of hard X-ray emitting WDs by cross-correlating the McCook & Sion (1999) catalog of WDs with the ROSAT point source database. We have verified the position of the WD, analysed the ROSAT data and extracted X-ray spectra to confirm the hard X-ray component. Since the only current explanation for hard X-ray emission from a WD involves a stellar companion and only five of the ~40 WDs that exhibit hard X-ray emission are known binary systems, we wish to investigate whether hard X-ray emssion is a useful diagnostic for the presence of companions to WDs. We request KPNO 2.1m SQIID near infrared photometric observations of a sample of 34 WDs, 23 of which exhibit hard X-ray emission, to look for an infrared excess consistent with the presence of a stellar companion.

  16. Detecting and Segregating Black Tip-Damaged Wheat Kernels Using Visible and Near Infrared Spectroscopy

    USDA-ARS?s Scientific Manuscript database

    Detection of individual wheat kernels with black tip symptom (BTS) and black tip damage (BTD) was demonstrated using near infrared reflectance spectroscopy (NIRS) and silicon light-emitting-diode (LED) based instruments. The two instruments tested, a single kernel near-infrared spectroscopy instrume...

  17. Ultrafast Nonlinear Excitation Dynamics of Black Phosphorus Nanosheets from Visible to Mid-Infrared.

    PubMed

    Wang, Kangpeng; Szydłowska, Beata M; Wang, Gaozhong; Zhang, Xiaoyan; Wang, Jing Jing; Magan, John J; Zhang, Long; Coleman, Jonathan N; Wang, Jun; Blau, Werner J

    2016-07-26

    The recent progress on black phosphorus makes it a promising candidate material for broadband nanophotonic devices, especially operating in the mid-infrared spectral region. Here, the excited carrier dynamics and nonlinear optical response of unoxidized black phosphorus nanosheets and their wavelength dependence were systematically studied from 800 nm to 2.1 μm. The wavelength-dependent relaxation times of black phosphorus nanosheets are determined to be 360 fs to 1.36 ps with photon energies from 1.55 to 0.61 eV. In a comparative study with graphene, we found that black phosphorus has a faster carrier relaxation in near- and mid-infrared region. With regard to nonlinear optical absorption, the response of black phosphorus significantly increases from near- to mid-infrared, and black phosphorus is also confirmed to be better as saturable absorber to MoS2 in infrared region.

  18. Microprocessing of human hard tooth tissues surface by mid-infrared erbium lasers radiation

    NASA Astrophysics Data System (ADS)

    Belikov, Andrey V.; Shatilova, Ksenia V.; Skrypnik, Alexei V.

    2015-03-01

    A new method of hard tooth tissues laser treatment is described. The method consists in formation of regular microdefects on tissue surface by mid-infrared erbium laser radiation with propagation ratio M2<2 (Er-laser microprocessing). Proposed method was used for preparation of hard tooth tissues surface before filling for improvement of bond strength between tissues surface and restorative materials, microleakage reduction between tissues surface and restorative materials, and for caries prevention as a result of increasing microhardness and acid resistance of tooth enamel.

  19. Infrared photometry of the black hole candidate Sagittarius A*

    NASA Technical Reports Server (NTRS)

    Close, Laird M.; Mccarthy, Donald W. JR.; Melia, Fulvio

    1995-01-01

    An infrared source has been imaged within 0.2 +/- 0.3 arcseconds of the unique Galactic center radio source Sgr A* High angular resolution (averaged value of the Full Width at Half Maximum (FWHM) approximately 0.55 arcseconds) was achieved by rapid (approximately 50 Hz) real-time images motion compensation. The source's near-infrared magnitudes (K = 12.1 +/- 0.3, H = 13.7 +/- 0.3, and J = 16.6 +/- 0.4) are consistent with a hot object reddened by the local extinction A(sub v) approximately 27). At the 3 sigma level of confidence, a time series of 80 images limits the source variability to less than 50% on timescales from 3 to 30 minutes. The photometry is consistent with the emission from a simple accretion disk model for a approximately 1 x 10(exp 6) solar mass black hole. However, the fluxes are also consistent with a hot luminous (L approximately 10(exp 3.5) to 10(exp 4-6) solar luminosity) central cluster star positionally coincident with Sgr A*.

  20. Compensating the Degradation of Near-Infrared Absorption of Black Silicon Caused by Thermal Annealing.

    PubMed

    Wang, Yanchao; Gao, Jinsong; Yang, Haigui; Wang, Xiaoyi; Shen, Zhenfeng

    2016-12-01

    We propose the use of thin Ag film deposition to remedy the degradation of near-infrared (NIR) absorption of black Si caused by high-temperature thermal annealing. A large amount of random and irregular Ag nanoparticles are formed on the microstructural surface of black Si after Ag film deposition, which compensates the degradation of NIR absorption of black Si caused by thermal annealing. The formation of Ag nanoparticles and their contributions to NIR absorption of black Si are discussed in detail.

  1. How to predict the sugariness and hardness of melons: A near-infrared hyperspectral imaging method.

    PubMed

    Sun, Meijun; Zhang, Dong; Liu, Li; Wang, Zheng

    2017-03-01

    Hyperspectral imaging (HSI) in the near-infrared (NIR) region (900-1700nm) was used for non-intrusive quality measurements (of sweetness and texture) in melons. First, HSI data from melon samples were acquired to extract the spectral signatures. The corresponding sample sweetness and hardness values were recorded using traditional intrusive methods. Partial least squares regression (PLSR), principal component analysis (PCA), support vector machine (SVM), and artificial neural network (ANN) models were created to predict melon sweetness and hardness values from the hyperspectral data. Experimental results for the three types of melons show that PLSR produces the most accurate results. To reduce the high dimensionality of the hyperspectral data, the weighted regression coefficients of the resulting PLSR models were used to identify the most important wavelengths. On the basis of these wavelengths, each image pixel was used to visualize the sweetness and hardness in all the portions of each sample. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. IS THE LATE NEAR-INFRARED BUMP IN SHORT-HARD GRB 130603B DUE TO THE LI-PACZYNSKI KILONOVA?

    SciTech Connect

    Jin, Zhi-Ping; Fan, Yi-Zhong; Wei, Da-Ming; Xu, Dong; Wu, Xue-Feng

    2013-09-20

    Short-hard gamma-ray bursts (GRBs) are widely believed to be produced by the merger of two binary compact objects, specifically by two neutron stars or by a neutron star orbiting a black hole. According to the Li-Paczynski kilonova model, the merger would launch sub-relativistic ejecta and a near-infrared/optical transient would then occur, lasting up to days, which is powered by the radioactive decay of heavy elements synthesized in the ejecta. The detection of a late bump using the Hubble Space Telescope (HST) in the near-infrared afterglow light curve of the short-hard GRB 130603B is indeed consistent with such a model. However, as shown in this Letter, the limited HST near-infrared light curve behavior can also be interpreted as the synchrotron radiation of the external shock driven by a wide mildly relativistic outflow. In such a scenario, the radio emission is expected to peak with a flux of ∼100 μJy, which is detectable for current radio arrays. Hence, the radio afterglow data can provide complementary evidence on the nature of the bump in GRB 130603B. It is worth noting that good spectroscopy during the bump phase in short-hard bursts can test the validity of either model above, analogous to spectroscopy of broad-lined Type Ic supernova in long-soft GRBs.

  3. Hard X-ray spectra of neutron stars and black hole candidates

    NASA Technical Reports Server (NTRS)

    Durouchoux, P.; Mahoney, W.; Clenet, Y.; Ling, J.; Wallyn, P.; Wheaton, W.; Corbet, S.; Chapuis, C.

    1997-01-01

    The hard X-ray behavior of several X-ray binary systems containing a neutron star or a black hole candidate is analyzed in an attempt to determine the specific signature of these categories of compact objects. Limiting the consideration to two subclasses of neutron stars, Atoll sources and non-pulsating Z sources, it appears that only the Atoll sources have a spectral behavior similar to black holes. It is proposed that Atoll sources are weakly magnetized neutron stars, whereas Z sources are small radius moderate magnetized neutron stars. Large magnetic fields funnel the accreting matter, thus preventing spherical accretion and free fall if the neutron star radius is smaller than the last stable accreting orbit. Weak magnetic fields do not have this effect, and blackbody soft photons from the stellar surface are upscattered on the relativistic infalling matter, leading to excess hard X-rays. This excess is visible in two of the observed Atoll sources and in the spectrum of a black hole candidate. In the case of a Z source, a lack of photons was remarked, providing a possible signature to distinguish between these classes of objects.

  4. Hard X-ray spectra of neutron stars and black hole candidates

    NASA Technical Reports Server (NTRS)

    Durouchoux, P.; Mahoney, W.; Clenet, Y.; Ling, J.; Wallyn, P.; Wheaton, W.; Corbet, S.; Chapuis, C.

    1997-01-01

    The hard X-ray behavior of several X-ray binary systems containing a neutron star or a black hole candidate is analyzed in an attempt to determine the specific signature of these categories of compact objects. Limiting the consideration to two subclasses of neutron stars, Atoll sources and non-pulsating Z sources, it appears that only the Atoll sources have a spectral behavior similar to black holes. It is proposed that Atoll sources are weakly magnetized neutron stars, whereas Z sources are small radius moderate magnetized neutron stars. Large magnetic fields funnel the accreting matter, thus preventing spherical accretion and free fall if the neutron star radius is smaller than the last stable accreting orbit. Weak magnetic fields do not have this effect, and blackbody soft photons from the stellar surface are upscattered on the relativistic infalling matter, leading to excess hard X-rays. This excess is visible in two of the observed Atoll sources and in the spectrum of a black hole candidate. In the case of a Z source, a lack of photons was remarked, providing a possible signature to distinguish between these classes of objects.

  5. Cosmological evolution of supermassive black holes in galactic centers unveiled by hard X-ray observations.

    PubMed

    Ueda, Yoshihiro

    2015-01-01

    We review the current understanding of the cosmological evolution of supermassive black holes in galactic centers elucidated by X-ray surveys of active galactic nuclei (AGNs). Hard X-ray observations at energies above 2 keV are the most efficient and complete tools to find "obscured" AGNs, which are dominant populations among all AGNs. Combinations of surveys with various flux limits and survey area have enabled us to determine the space number density and obscuration properties of AGNs as a function of luminosity and redshift. The results have essentially solved the origin of the X-ray background in the energy band below ∼10 keV. The downsizing (or anti-hierarchical) evolution that more luminous AGNs have the space-density peak at higher redshifts has been discovered, challenging theories of galaxy and black hole formation. Finally, we summarize unresolved issues on AGN evolution and prospects for future X-ray missions.

  6. Cosmological evolution of supermassive black holes in galactic centers unveiled by hard X-ray observations

    PubMed Central

    UEDA, Yoshihiro

    2015-01-01

    We review the current understanding of the cosmological evolution of supermassive black holes in galactic centers elucidated by X-ray surveys of active galactic nuclei (AGNs). Hard X-ray observations at energies above 2 keV are the most efficient and complete tools to find “obscured” AGNs, which are dominant populations among all AGNs. Combinations of surveys with various flux limits and survey area have enabled us to determine the space number density and obscuration properties of AGNs as a function of luminosity and redshift. The results have essentially solved the origin of the X-ray background in the energy band below ∼10 keV. The downsizing (or anti-hierarchical) evolution that more luminous AGNs have the space-density peak at higher redshifts has been discovered, challenging theories of galaxy and black hole formation. Finally, we summarize unresolved issues on AGN evolution and prospects for future X-ray missions. PMID:25971656

  7. Hard x-ray phase contrast imaging of black lipid membranes

    SciTech Connect

    Beerlink, A.; Mell, M.; Tolkiehn, M.; Salditt, T.

    2009-11-16

    We report hard x-ray phase contrast imaging of black lipid membranes, freely suspended over a micromachined aperture in an aqueous solution. Biomolecular and organic substances can thus be probed in hydrated environments by parallel beam propagation imaging, using coherent multi-kilo-electronvolt x-ray radiation. The width of the thinning film can be resolved from analysis of the intensity fringes in the Fresnel diffraction regime down to about 200 nm. The thinning process, in which solvent is expelled from the space in between two opposing monolayers, is monitored, and the domain walls between coexisting domains of swollen and thinned membrane patches are characterized.

  8. THE HARD X-RAY SPECTRUM OF NGC 1365: SCATTERED LIGHT, NOT BLACK HOLE SPIN

    SciTech Connect

    Miller, L.; Turner, T. J.

    2013-08-10

    Active galactic nuclei (AGNs) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (1) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (2) neglect of the effect of Compton scattering on transmitted spectra, and (3) inadequate modeling of the spectrum of scattered X-rays. The scattered spectrum is geometry-dependent and, for high global covering factors, may dominate above 10 keV. We further show that, in models of circumnuclear gas, the suppression of the observed hard X-ray flux by reprocessing may be no larger than required by the ''light bending'' model invoked for inner disk reflection, and the expected emission line strengths lie within the observed range. We conclude that the time-invariant ''red wing'' in AGN X-ray spectra is probably caused by continuum transmitted through and scattered from circumnuclear gas, not by highly redshifted line emission, and that measurement of black hole spin is not possible.

  9. Hard X-Rays from a Complete Sample of the Brightest Ultraluminous Infrared Galaxies

    NASA Technical Reports Server (NTRS)

    Sanders, David B.

    2003-01-01

    We were awarded 70kS of XMM-Newton spacecraft time using the Epic pn camera to observe three ultraluminous infrared galaxies (ULIGs) in order to measure the spectral shape of their hard X-Ray emission, and to use this information to search for the presence of an highly obscured active galactic nucleus (AGN), and to separate out the contributions from a putative starburst. By observing three objects we hope to be able to better assess the role of AGN in the complete class of ULIGs and therefore to better constrain their contribution to the X-ray background. XMM-Newton was deemed to be better suited to our proposed measurements of ULIGs than the Chandra X-ray observatory due to its larger aperture and better sensitivity to hard (2-10 keV) X-rays.

  10. Hard X-Rays from a Complete Sample of the Brightest Ultraluminous Infrared Galaxies

    NASA Technical Reports Server (NTRS)

    Sanders, David B.

    2003-01-01

    We were awarded 70kS of XMM-Newton spacecraft time using the Epic pn camera to observe three ultraluminous infrared galaxies (ULIGs) in order to measure the spectral shape of their hard X-Ray emission, and to use this information to search for the presence of an highly obscured active galactic nucleus (AGN), and to separate out the contributions from a putative starburst. By observing three objects we hope to be able to better assess the role of AGN in the complete class of ULIGs and therefore to better constrain their contribution to the X-ray background. XMM-Newton was deemed to be better suited to our proposed measurements of ULIGs than the Chandra X-ray observatory due to its larger aperture and better sensitivity to hard (2-10 keV) X-rays.

  11. Bait stations, hard mast, and black bear population growth in Great Smoky Mountains National Park

    USGS Publications Warehouse

    Clark, Joseph D.; van Manen, Frank T.; Pelton, Michael R.

    2005-01-01

    Bait-station surveys are used by wildlife managers as an index to American black bear (Ursus americanus) population abundance, but the relationship is not well established. Hard mast surveys are similarly used to assess annual black bear food availability which may affect mortality and natality rates. We used data collected in Great Smoky Mountains National Park (GSMNP) from 1989 to 2003 to determine whether changes in the bait-station index (ΔBSI) were associated with estimated rates of bear population growth (λ) and whether hard mast production was related to bear visitation to baits. We also evaluated whether hard mast production from previous years was related to λ. Estimates of λ were based on analysis of capture-recapture data with the Pradel temporal symmetry estimator. Using the Akaike's Information Criterion (AIC), our analysis revealed no direct relationship between ΔBSI and λ. A simulation analysis indicated that our data were adequate to detect a relationship had one existed. Model fit was marginally improved when we added total oak mast production of the previous year as an interaction term suggesting that the BSI was confounded with environmental variables. Consequently the utility of the bait-station survey as a population monitoring technique is questionable at the spatial and temporal scales we studied. Mast survey data, however, were valuable covariates of λ. Population growth for a given year was negatively related to oak mast production 4 and 5 years prior. That finding supported our hypothesis that mast failures can trigger reproductive synchrony, which may not be evident from the trapped sample until years later.

  12. A DEEP RADIO SURVEY OF HARD STATE AND QUIESCENT BLACK HOLE X-RAY BINARIES

    SciTech Connect

    Miller-Jones, J. C. A.; Jonker, P. G.; Maccarone, T. J.; Calvelo, D. E.; Nelemans, G.

    2011-09-20

    We have conducted a deep radio survey of a sample of black hole X-ray binaries in the hard and quiescent states to determine whether any systems were sufficiently bright for astrometric follow-up with high-sensitivity very long baseline interferometric arrays. The one hard-state system, Swift J1753.5-0127, was detected at a level of 0.5 mJy beam{sup -1}. All 11 quiescent systems were not detected. In the three cases with the highest predicted quiescent radio brightnesses (GRO J0422+32, XTE J1118+480, and GRO J1655-40), the new capabilities of the Expanded Very Large Array were used to reach noise levels as low as 2.6 {mu}Jy beam{sup -1}. None of the three sources were detected to 3{sigma} upper limits of 8.3, 7.8, and 14.2 {mu}Jy beam{sup -1}, respectively. These observations represent the most stringent constraints to date on quiescent radio emission from black hole X-ray binaries. The uncertainties in the source distances, quiescent X-ray luminosities at the times of the observations, and the power-law index of the empirical correlation between radio and X-ray luminosities make it impossible to determine whether these three sources are significantly less luminous in the radio band than expected. Thus it is not clear whether that correlation holds all the way down to quiescence for all black hole X-ray binaries.

  13. Selection of infrared black(s) for the Space Infra-Red Telescope Facility (SIRTF): a surface-by-surface performance comparison

    NASA Astrophysics Data System (ADS)

    Dinger, Ann S.

    1994-10-01

    SIRTF, the Space Infrared Telescope Facility, is planned to be the final one of NASA's four great observatories. It is a cryogenically cooled telescope designed to perform background- limited observations at all wavelengths between 2 and 220 micrometers . This stringent straylight requirement necessitates the use of infrared black coatings on all non-optical telescope surfaces. In order to make an informed decision, the SIRTF Study Office supported a long- range program to characterize the performance of a variety of black coatings over the full SIRTF wavelength range. Measurements of both specular reflectance and BRDF made by Sheldon Smith were incorporated into a model that predicts the blacks' BRDF coefficients at other wavelengths. The restrahlen reflectance peaks of Martin Black and Martin Infrablack at 2.2 and 5.4 micrometers are included in the model. An APART analysis of the current SIRTF telescope design was performed at wavelengths of 2.2, 3.5, 12.5, 60, and 200 micrometers . Evaluation of the relative performances of Martin Optical Black and Ames 24E2 on several critical surfaces led to the conclusion that the SIRTF straylight rejection could be enhanced by selecting different coatings for different surfaces. A very diffuse black is best on the mirror stops and secondary support struts, while a specular black could be a better choice for the vaned telescope barrel. Many coatings that are black and diffusely scattering at short wavelengths become quite bright and specular at long wavelengths. Extreme caution must be taken when using a black that becomes specular on any surface that can be seen from the telescope plane.

  14. Self-organized, effective medium black silicon antireflection structures for silicon optics in the mid-infrared

    NASA Astrophysics Data System (ADS)

    Steglich, Martin; Käsebier, Thomas; Kley, Ernst-Bernhard; Tünnermann, Andreas

    2016-09-01

    Thanks to its high quality and low cost, silicon is the material of choice for optical devices operating in the mid-infrared (MIR; 2 μm to 6 μm wavelength). Unfortunately in this spectral region, the refractive index is comparably high (about 3.5) and leads to severe reflection losses of about 30% per interface. In this work, we demonstrate that self-organized, statistical Black Silicon structures, fabricated by Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE), can be used to effectively suppress interface reflection. More importantly, it is shown that antireflection can be achieved in an image-preserving, non-scattering way. This enables Black Silicon antireflection structures (ARS) for imaging applications in the MIR. It is demonstrated that specular transmittances of 97% can be easily achieved on both flat and curved substrates, e.g. lenses. Moreover, by a combined optical and morphological analysis of a multitude of different Black Silicon ARS, an effective medium criterion for the examined structures is derived that can also be used as a design rule for maximizing sample transmittance in a desired wavelength range. In addition, we show that the mechanical durability of the structures can be greatly enhanced by coating with hard dielectric materials like diamond-like carbon (DLC), hence enabling practical applications. Finally, the distinct advantages of statistical Black Silicon ARS over conventional AR layer stacks are discussed: simple applicability to topological substrates, absence of thermal stress and cost-effectiveness.

  15. Maize kernel hardness classification by near infrared (NIR) hyperspectral imaging and multivariate data analysis.

    PubMed

    Williams, Paul; Geladi, Paul; Fox, Glen; Manley, Marena

    2009-10-27

    The use of near infrared (NIR) hyperspectral imaging and hyperspectral image analysis for distinguishing between hard, intermediate and soft maize kernels from inbred lines was evaluated. NIR hyperspectral images of two sets (12 and 24 kernels) of whole maize kernels were acquired using a Spectral Dimensions MatrixNIR camera with a spectral range of 960-1662 nm and a sisuChema SWIR (short wave infrared) hyperspectral pushbroom imaging system with a spectral range of 1000-2498 nm. Exploratory principal component analysis (PCA) was used on absorbance images to remove background, bad pixels and shading. On the cleaned images, PCA could be used effectively to find histological classes including glassy (hard) and floury (soft) endosperm. PCA illustrated a distinct difference between glassy and floury endosperm along principal component (PC) three on the MatrixNIR and PC two on the sisuChema with two distinguishable clusters. Subsequently partial least squares discriminant analysis (PLS-DA) was applied to build a classification model. The PLS-DA model from the MatrixNIR image (12 kernels) resulted in root mean square error of prediction (RMSEP) value of 0.18. This was repeated on the MatrixNIR image of the 24 kernels which resulted in RMSEP of 0.18. The sisuChema image yielded RMSEP value of 0.29. The reproducible results obtained with the different data sets indicate that the method proposed in this paper has a real potential for future classification uses.

  16. Prediction of tablet hardness based on near infrared spectra of raw mixed powders by chemometrics.

    PubMed

    Otsuka, Makoto; Yamane, Ikuro

    2006-07-01

    The purpose of this research is to elucidate the effect of lubricant mixing on tablet hardness by near-infrared (NIR) chemometrics as a basic study of process analytical technology. Formulation cellulose (F-C) consisted of sulpyrine (SP), microcrystalline cellulose (MC), and magnesium stearate (MgSt). Formulation lactose/starch (F-L) consisted of SP bulk drug powder, spray-dried lactose (SL), corn starch (CS), and MgSt. First, F-L and F-C without MgSt were mixed in a twin-shell mixer for 60 min. MgSt was added to the mixed powder, and was mixed for various mixing times, after which the mixed powders were compressed by 8-mm diameter punch and die. NIR spectra of raw mixed powders of F-L and F-C were taken using a reflection type of Fourier transform NIR spectra spectrometer, and chemometric analysis was performed using principal component regression (PCR). The tablet hardnesses of F-L and F-C decreased with increasing mixing time. All NIR spectra of the mixed powders of F-L and F-C fluctuated depending on mixing time. In order to predict tablet hardness before tablet compression, NIR spectra of F-L and F-C mixed powders were analyzed and evaluated for hardness by PCR. The minimum standard error of cross-validation values could be realized by using five- and six-principal component models, respectively. In the cases of F-L and F-C, the relationships between the actual and predicted tablet hardnesses showed straight lines, respectively. In the regression vectors of F-L and FC, the peaks related to hydrogen groups of SP, CS, and MC appeared as positive peaks. In contrast, the peaks related to hydrocarbon due to MgSt appeared as negative peaks in the regression vectors. The calibration models to evaluate the tablet hardness were obtained based on NIR spectra of raw mixed powders by PCR. This approach to predicting tablet hardness prior to compression could be used as a routine test to indicate the quality of the final product without spending time and energy to produce

  17. TRACING THE REVERBERATION LAG IN THE HARD STATE OF BLACK HOLE X-RAY BINARIES

    SciTech Connect

    De Marco, B.; Ponti, G.; Nandra, K.; Muñoz-Darias, T.

    2015-11-20

    We report results obtained from a systematic analysis of X-ray lags in a sample of black hole X-ray binaries, with the aim of assessing the presence of reverberation lags and studying their evolution during outburst. We used XMM-Newton and simultaneous Rossi X-ray Timing Explorer (RXTE) observations to obtain broadband energy coverage of both the disk and the hard X-ray Comptonization components. In most cases the detection of reverberation lags is hampered by low levels of variability-power signal-to-noise ratio (typically when the source is in a soft state) and/or short exposure times. The most detailed study was possible for GX 339-4 in the hard state, which allowed us to characterize the evolution of X-ray lags as a function of luminosity in a single source. Over all the sampled frequencies (∼0.05–9 Hz), we observe the hard lags intrinsic to the power-law component, already well known from previous RXTE studies. The XMM-Newton soft X-ray response allows us to detail the disk variability. At low frequencies (long timescales) the disk component always leads the power-law component. On the other hand, a soft reverberation lag (ascribable to thermal reprocessing) is always detected at high frequencies (short timescales). The intrinsic amplitude of the reverberation lag decreases as the source luminosity and the disk fraction increase. This suggests that the distance between the X-ray source and the region of the optically thick disk where reprocessing occurs gradually decreases as GX 339-4 rises in luminosity through the hard state, possibly as a consequence of reduced disk truncation.

  18. A magnetic model for low/hard state of black hole binaries

    NASA Astrophysics Data System (ADS)

    Ye, Yong-Chun; Wang, Ding-Xiong; Huang, Chang-Yin; Cao, Xiao-Feng

    2016-03-01

    A magnetic model for the low/hard state (LHS) of two black hole X-ray binaries (BHXBs), H1743-322 and GX 339-4, is proposed based on transport of the magnetic field from a companion into an accretion disk around a black hole (BH). This model consists of a truncated thin disk with an inner advection-dominated accretion flow (ADAF). The spectral profiles of the sources are fitted in agreement with the data observed at four different dates corresponding to the rising phase of the LHS. In addition, the association of the LHS with a quasi-steady jet is modeled based on transport of magnetic field, where the Blandford-Znajek (BZ) and Blandford-Payne (BP) processes are invoked to drive the jets from BH and inner ADAF. It turns out that the steep radio/X-ray correlations observed in H1743-322 and GX 339-4 can be interpreted based on our model.

  19. Interpretation of the hardness-luminosity diagram of black-hole X-ray transients

    NASA Astrophysics Data System (ADS)

    Kylafis, Nikolaos; Belloni, Tomaso

    Black-hole X-ray transients (BHTs) often exhibit during their outbursts a characteristic q-shaped curve in a hardness-luminosity diagram. A rich phenomenology has been accumulated over the years regarding this diagram. It is desirable to have a physical picture of BHTs over the entire q-shaped curve, which hopefully will have predictive power. Such a physical picture is proposed here and it relies on two assumptions, easily justifiable. The first is that the mass-accretion rate to the black hole in a BHT outburst has a generic “bell-shaped” form. This is guaranteed by the observational fact that all BHTs start their outburst and end it at the quiescent state, i.e., at very low accretion rates. The mass-accretion rate increases, reaches values close to the Eddington rate, and decreases again. The second assumption is that at low accretion rates the accretion disk is geometrically thick, ADAF-like, while at high accretion rates it is thin. This assumption is generally accepted. Unlike phenomenological pictures typically invoked for BHTs, our physical picture explains the formation and the destruction of jets as well as why BHTs traverse the q-shaped curve always in the counterclockwise direction and that no BHT is expected to ever traverse it in the clockwise direction. In addition, it explains the q-shaped curve with only one parameter, the accretion rate.

  20. Mid-infrared mode-locked pulse generation with multilayer black phosphorus as saturable absorber.

    PubMed

    Qin, Zhipeng; Xie, Guoqiang; Zhao, Chujun; Wen, Shuangchun; Yuan, Peng; Qian, Liejia

    2016-01-01

    A mid-infrared saturable absorber mirror is successfully fabricated by transferring the mechanically exfoliated black phosphorus onto the gold-coated mirror. With the as-prepared black phosphorus saturable absorber mirror, a continuous-wave passively mode-locked Er:ZBLAN fiber laser is demonstrated at the wavelength of 2.8 μm, which delivers a maximum average output power of 613 mW, a repetition rate of 24 MHz, and a pulse duration of 42 ps. To the best of our knowledge, this is the first time a black phosphorus mode-locked laser at 2.8 μm wavelength has been demonstrated. Our results demonstrate the feasibility of black phosphorus flake as a new two-dimensional material for application in mid-infrared ultrafast photonics.

  1. Data-driven imbalance and hard particle detection in rotating machinery using infrared thermal imaging

    NASA Astrophysics Data System (ADS)

    Janssens, Olivier; Loccufier, Mia; Van de Walle, Rik; Van Hoecke, Sofie

    2017-05-01

    Currently, temperature-based condition monitoring cannot be used to accurately identify potential faults early in a rotating machines' lifetime since temperature changes are only detectable when the fault escalates. However, currently only point measurements, i.e. thermocouples, are used. In this article, infrared thermal imaging is used which - as opposed to simple thermocouples - provides spatial temperature information. This information proves crucial for the identification of several machine conditions and faults. In this paper the conditions considered are outer-raceway damage in bearings, hard-particle contamination in lubricant and several gradations of shaft imbalance. The fault detection is done using an image processing and machine learning solution which can accurately detect the majority of the faults and conditions in our data set.

  2. Multi-spectral black meta-infrared detectors (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Krishna, Sanjay

    2016-09-01

    There is an increased emphasis on obtaining imaging systems with on-demand spectro-polarimetric information at the pixel level. Meta-infrared detectors in which infrared detectors are combined with metamaterials are a promising way to realize this. The infrared region is appealing due to the low metallic loss, large penetration depth of the localized field and the larger feature sizes compared to the visible region. I will discuss approaches to realize multispectral detectors including our recent work on double metal meta-material design combined with Type II superlattices that have demonstrated enhanced quantum efficiency (collaboration with Padilla group at Duke University).

  3. Evaluation of a pyroelectric detector with a carbon multiwalled nanotube black coating in the infrared.

    PubMed

    Theocharous, E; Deshpande, R; Dillon, A C; Lehman, J

    2006-02-20

    The performance of a pyroelectric detector with a carbon multiwalled nanotube coating was evaluated in the 0.9-14 microm wavelength range. The relative spectral responsivity of this detector was shown to be flat over most of the wavelength range examined, and the spectral flatness was shown to be comparable to the best infrared black coatings currently available. This finding is promising because black coatings with spectrally flat absorbance profiles are usually associated with the highest absorbance values. The performance of the detector (in terms of noise equivalent power and specific detectivity) was limited by the very thick (250 microm thick) LiNbO3 pyroelectric crystal onto which the coating was deposited. The responsivity of this detector was shown to be linear in the 0.06-2.8 mW radiant power range, and its spatial uniformity was comparable to that of other pyroelectric detectors that use different types of black coating. The carbon nanotube coatings were reported to be much more durable than other infrared black coatings, such as metal blacks, that are commonly used to coat thermal detectors in the infrared. This, in combination with their excellent spectral flatness, suggests that carbon nanotube coatings appear extremely promising for thermal detection applications in the infrared.

  4. Near-infrared and optical observations of the failed outbursts of black hole binary XTE J1550-564

    NASA Astrophysics Data System (ADS)

    Curran, P. A.; Chaty, S.

    2013-09-01

    Context. A number of low mass X-ray binaries (LMXBs) undergo "failed outbursts" in which, instead of evolving through the canonical states, they remain in a hard state throughout the outburst. While the sources of X-ray and radio emission in the hard state are relatively well understood, the origin of the near-infrared (NIR) and optical emission is more complex though it likely stems from an amalgam of different emission processes, occurring as it does, at the intersecting wavelengths of those processes. Aims: We aim to identify the NIR/optical emission region(s) during a number of failed outbursts of one such LMXB and black hole candidate, XTE J1550-564, in order to confirm or refute their classification as hard-state, failed outbursts. Methods: We present unique NIR/optical images and spectra, obtained with the ESO-New Technology Telescope, during the failed outbursts of 2001 and 2000. We compare the NIR/optical photometric, timing, and spectral properties with those expected for the different emission mechanisms in the various LMXB states. Results: The NIR/optical data are consistent with having come from reprocessing of X-rays in the accretion disk, with no evidence of direct thermal emission from the disk itself. However, the observed variability in high-cadence NIR light curves suggest that the radio jet extends and contributes to the NIR wavelengths. Conclusions: We find that these failed outbursts did not transition to an intermediate state but remained in a true, hard state where there was no sign of jet quenching or deviation from the observed hard state correlations. Based on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility.

  5. Hard X-Ray Emission of the Luminous Infrared Galaxy NGC 6240 as Observed by Nustar

    NASA Technical Reports Server (NTRS)

    Puccetti, S.; Comastri, A.; Bauer, F. E.; Brandt, W. N.; Fiore, F.; Harrison, F. A.; Luo, B.; Stern, D.; Urry, C. M.; Alexander, D. M.; Annuar, A.; Arévalo, P.; Balokovic, M.; Boggs, S. E.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Koss, M. J.; La Massa, S.; Marinucci, A.; Ricci, C.; Walton, D. J.; Zappacosta, L.; Zhang, W.

    2016-01-01

    We present a broadband (approx.0.3-70 keV) spectral and temporal analysis of NuSTAR observations of the luminous infrared galaxy NGC 6240 combined with archival Chandra, XMM-Newton, and BeppoSAX data. NGC 6240 is a galaxy in a relatively early merger state with two distinct nuclei separated by approx.1.5. Previous Chandra observations resolved the two nuclei and showed that they are both active and obscured by Compton-thick material. Although they cannot be resolved by NuSTAR, we were able to clearly detect, for the first time, both the primary and the reflection continuum components thanks to the unprecedented quality of the NuSTAR data at energies >10 keV. The NuSTAR hard X-ray spectrum is dominated by the primary continuum piercing through an absorbing column density which is mildly optically thick to Compton scattering (tau approx. = 1.2, NH approx. 1.5×10(exp 24)/sq cm. We detect moderately hard X-ray (>10 keV) flux variability up to 20% on short (15-20 ks) timescales. The amplitude of the variability is largest at approx..30 keV and is likely to originate from the primary continuum of the southern nucleus. Nevertheless, the mean hard X-ray flux on longer timescales (years) is relatively constant. Moreover, the two nuclei remain Compton-thick, although we find evidence of variability in the material along the line of sight with column densities NH < or = 2×10(exp 23)/sq cm over long (approx.3-15 yr) timescales. The observed X-ray emission in the NuSTAR energy range is fully consistent with the sum of the best-fit models of the spatially resolved Chandra spectra of the two nuclei.

  6. Hard X-Ray Emission of the Luminous Infrared Galaxy NGC 6240 as Observed by Nustar

    NASA Technical Reports Server (NTRS)

    Puccetti, S.; Comastri, A.; Bauer, F. E.; Brandt, W. N.; Fiore, F.; Harrison, F. A.; Luo, B.; Stern, D.; Urry, C. M.; Alexander, D. M.; hide

    2016-01-01

    We present a broadband (approx.0.3-70 keV) spectral and temporal analysis of NuSTAR observations of the luminous infrared galaxy NGC 6240 combined with archival Chandra, XMM-Newton, and BeppoSAX data. NGC 6240 is a galaxy in a relatively early merger state with two distinct nuclei separated by approx.1.5. Previous Chandra observations resolved the two nuclei and showed that they are both active and obscured by Compton-thick material. Although they cannot be resolved by NuSTAR, we were able to clearly detect, for the first time, both the primary and the reflection continuum components thanks to the unprecedented quality of the NuSTAR data at energies >10 keV. The NuSTAR hard X-ray spectrum is dominated by the primary continuum piercing through an absorbing column density which is mildly optically thick to Compton scattering (tau approx. = 1.2, NH approx. 1.5×10(exp 24)/sq cm. We detect moderately hard X-ray (>10 keV) flux variability up to 20% on short (15-20 ks) timescales. The amplitude of the variability is largest at approx..30 keV and is likely to originate from the primary continuum of the southern nucleus. Nevertheless, the mean hard X-ray flux on longer timescales (years) is relatively constant. Moreover, the two nuclei remain Compton-thick, although we find evidence of variability in the material along the line of sight with column densities NH < or = 2×10(exp 23)/sq cm over long (approx.3-15 yr) timescales. The observed X-ray emission in the NuSTAR energy range is fully consistent with the sum of the best-fit models of the spatially resolved Chandra spectra of the two nuclei.

  7. Detection of the first infra-red quasi-periodic oscillation in a black hole X-ray binary

    NASA Astrophysics Data System (ADS)

    Kalamkar, M.; Casella, P.; Uttley, P.; O'Brien, K.; Russell, D.; Maccarone, T.; van der Klis, M.; Vincentelli, F.

    2016-08-01

    We present the analysis of fast variability of Very Large Telescope/ISAAC (Infrared Spectrometer And Array Camera) (infra-red), XMM-Newton/OM (optical) and EPIC-pn (X-ray), and RXTE/PCA (X-ray) observations of the black hole X-ray binary GX 339-4 in a rising hard state of its outburst in 2010. We report the first detection of a quasi-periodic oscillation (QPO) in the infra-red band (IR) of a black hole X-ray binary. The QPO is detected at 0.08 Hz in the IR as well as two optical bands (U and V). Interestingly, these QPOs are at half the X-ray QPO frequency at 0.16 Hz, which is classified as the type-C QPO; a weak sub-harmonic close to the IR and optical QPO frequency is also detected in X-rays. The band-limited sub-second time-scale variability is strongly correlated in IR/X-ray bands, with X-rays leading the IR by over 120 ms. This short time delay, shape of the cross-correlation function and spectral energy distribution strongly indicate that this band-limited variable IR emission is the synchrotron emission from the jet. A jet origin for the IR QPO is strongly favoured, but cannot be definitively established with the current data. The spectral energy distribution indicates a thermal disc origin for the bulk of the optical emission, but the origin of the optical QPO is unclear. We discuss our findings in the context of the existing models proposed to explain the origin of variability.

  8. J-Black: a stray light coating for optical and infrared systems

    NASA Astrophysics Data System (ADS)

    Waddell, Patrick; Black, David S.

    2016-07-01

    A new stray light coating, called J-Black, has been developed for NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA). The coating is a layered composition of Nextel-Suede 3101 primers and top coats and silicon carbide grit. J-Black has been applied to large areas of the SOFIA airborne telescope and is currently operating within the open cavity environment of the Boeing 747. Over a series of discrete filter bands, from 0.4 to 21 microns, J-Black optical and infrared reflectivity performance is compared with other available coatings. Measured total reflectance values are less than 2% at the longest wavelengths, including at high incidence angles. Detailed surface structure characteristics are also compared via electron and ion microscopy. Environmental tests applicable for aerospace applications are presented, as well as the detailed steps required to apply the coating.

  9. Determination of Endosperm Protein Secondary Structure in Hard Wheat Breeding Lines using Synchrotron Infrared Microspectroscopy

    SciTech Connect

    Wetzel, D.; Bonwell, E; Fritz, T; Fritz, A

    2008-01-01

    One molecular aspect of mature hard wheat protein quality for breadmaking is the relative amount of endosperm protein in the {alpha}-helix form compared with that in other secondary structure forms including {beta}-sheet. Modeling of {alpha}-helix and {beta}-sheet absorption bands that contribute to the amide I band at 1650 cm{sup -1} was applied to more than 1500 spectra in this study. The microscopic view of wheat endosperm is dominated by many large starch granules with protein in between. The spectrum produced from in situ microspectroscopy of this mixture is dominated by carbohydrate bands from the large starch granules that fill up the field. The high spatial resolution achievable with synchrotron infrared microspectroscopy enables revealing good in situ spectra of the protein located interstitially. Synchrotron infrared microspectroscopic mapping of 4 {mu}m thick frozen sections of endosperm in the subaleurone region provides spectra from a large number of pixels. Pixels with protein-dominated spectra are sorted out from among adjacent pixels to minimize the starch absorption and scattering contributions. Subsequent data treatment to extract information from the amide I band requires a high signal to noise ratio. Although spectral interference of the carbohydrate band on the amide band is not a problem, the scattering produced by the large starch granules diminishes the signal to noise ratio throughout the spectrum. High density mapping was done on beamlines U2B and U10B at the National Synchrotron Light Source at Brookhaven National Laboratory, Upton, NY. Mapping with a single masked spot size of 5.5 {mu}m diameter or confocal 5 {mu}mX5{mu}m spot size, respectively, on the two beamlines used produced spectra for new breeding lines under current consideration. Appropriate data treatment allows calculation of a numerical estimate of the {alpha}-helix population relative to other secondary protein structures from the position and shape of the amide I

  10. Determination of Endosperm Protein Secondary Structure in Hard Wheat Breeding Lines using Synchrotron Infrared Microspectroscopy

    SciTech Connect

    Bonwell,E.; Fisher, T.; Fritz, A.; Wetzel, D.

    2008-01-01

    One molecular aspect of mature hard wheat protein quality for breadmaking is the relative amount of endosperm protein in the a-helix form compared with that in other secondary structure forms including {beta}-sheet. Modeling of a-helix and {beta}-sheet absorption bands that contribute to the amide I band at 1650 cm-1 was applied to more than 1500 spectra in this study. The microscopic view of wheat endosperm is dominated by many large starch granules with protein in between. The spectrum produced from in situ microspectroscopy of this mixture is dominated by carbohydrate bands from the large starch granules that fill up the field. The high spatial resolution achievable with synchrotron infrared microspectroscopy enables revealing good in situ spectra of the protein located interstitially. Synchrotron infrared microspectroscopic mapping of 4 {mu}m thick frozen sections of endosperm in the subaleurone region provides spectra from a large number of pixels. Pixels with protein-dominated spectra are sorted out from among adjacent pixels to minimize the starch absorption and scattering contributions. Subsequent data treatment to extract information from the amide I band requires a high signal to noise ratio. Although spectral interference of the carbohydrate band on the amide band is not a problem, the scattering produced by the large starch granules diminishes the signal to noise ratio throughout the spectrum. High density mapping was done on beamlines U2B and U10B at the National Synchrotron Light Source at Brookhaven National Laboratory, Upton, NY. Mapping with a single masked spot size of 5.5 {mu}m diameter or confocal 5 {mu}m x 5 {mu}m spot size, respectively, on the two beamlines used produced spectra for new breeding lines under current consideration. Appropriate data treatment allows calculation of a numerical estimate of the a-helix population relative to other secondary protein structures from the position and shape of the amide I absorption band. Current

  11. Development of a new approach based on midwave infrared spectroscopy for post-consumer black plastic waste sorting in the recycling industry.

    PubMed

    Rozenstein, Offer; Puckrin, Eldon; Adamowski, Jan

    2017-10-01

    Waste sorting is key to the process of waste recycling. Exact identification of plastic resin and wood products using Near Infrared (NIR, 1-1.7µm) sensing is currently in use. Yet, dark targets characterized by low reflectance, such as black plastics, are hard to identify by this method. Following the recent success of Midwave Infrared (MWIR, 3-12µm) measurements to identify coloured plastic polymers, the aim of this study was to assess whether this technique is applicable to sorting black plastic polymers and wood products. We performed infrared reflectance contact measurements of 234 plastic samples and 29 samples of wood and paper products. Plastic samples included black, coloured and transparent Polyethylene Terephthalate (PET), Polyethylene (PE), Polyvinyl Chloride (PVC), Polypropylene (PP), Polylactic acid (PLA) and Polystyrene (PS). The spectral signatures of the black and coloured plastic samples were compared with clear plastic samples and signatures documented in the literature to identify the polymer spectral features in the presence of coloured material. This information was used to determine the spectral bands that best suit the sorting of black plastic polymers. The main NIR-MWIR absorption features of wood, cardboard and paper were identified as well according to the spectral measurements. Good agreement was found between our measurements and the absorption features documented in the literature. The new approach using MWIR spectral features appears to be useful for black plastics as it overcomes some of the limitations in the NIR region to identify them. The main limitation of this technique for industrial applications is the trade-off between the signal-to-noise ratio of the sensor operating in standoff mode and the speed at which waste is moved under the sensor. This limitation can be resolved by reducing the system's spectral resolution to 16cm(-1), which allows for faster spectra acquisition while maintaining a reasonable signal-to-noise ratio

  12. Nondestructive tablet hardness testing by near-infrared spectroscopy: a new and robust spectral best-fit algorithm.

    PubMed

    Kirsch, J D; Drennen, J K

    1999-03-01

    A new algorithm using common statistics was proposed for nondestructive near-infrared (near-IR) spectroscopic tablet hardness testing over a range of tablet potencies. The spectral features that allow near-IR tablet hardness testing were evaluated. Cimetidine tablets of 1-20% potency and 1-7 kp hardness were used for the development and testing of a new spectral best-fit algorithm for tablet hardness prediction. Actual tablet hardness values determined via a destructive diametral crushing test were used for construction of calibration models using principal component analysis/principal component regression (PCA/PCR) or the new algorithm. Both methods allowed the prediction of tablet hardness over the range of potencies studied. The spectral best-fit method compared favorably to the multivariate PCA/PCR method, but was easier to develop. The new approach offers advantages over wavelength-based regression models because the calculation of a spectral slope averages out the influence of individual spectral absorbance bands. The ability to generalize the hardness calibration over a range of potencies confirms the robust nature of the method.

  13. Infrared Emission from Kilonovae: The Case of the Nearby Short Hard Burst GRB 160821B

    NASA Astrophysics Data System (ADS)

    Kasliwal, Mansi M.; Korobkin, Oleg; Lau, Ryan M.; Wollaeger, Ryan; Fryer, Christopher L.

    2017-07-01

    We present constraints on Ks-band emission from one of the nearest short hard gamma-ray bursts, GRB 160821B, at z = 0.16, at three epochs. We detect a red relativistic afterglow from the jetted emission in the first epoch but do not detect any excess kilonova emission in the second two epochs. We compare upper limits obtained with Keck I/MOSFIRE to multi-dimensional radiative transfer models of kilonovae, that employ composition-dependent nuclear heating and LTE opacities of heavy elements. We discuss eight models that combine toroidal dynamical ejecta and two types of wind and one model with dynamical ejecta only. We also discuss simple, empirical scaling laws of predicted emission as a function of ejecta mass and ejecta velocity. Our limits for GRB 160821B constrain the ejecta mass to be lower than 0.03 M ⊙ for velocities greater than 0.1 c. At the distance sensitivity range of advanced LIGO, similar ground-based observations would be sufficiently sensitive to the full range of predicted model emission including models with only dynamical ejecta. The color evolution of these models shows that I-K color spans 7-16 mag, which suggests that even relatively shallow infrared searches for kilonovae could be as constraining as optical searches.

  14. OPTICAL AND NEAR-INFRARED MONITORING OF THE BLACK HOLE X-RAY BINARY GX 339-4 DURING 2002-2010

    SciTech Connect

    Buxton, Michelle M.; Bailyn, Charles D.; Capelo, Holly L.; Chatterjee, Ritaban; Dincer, Tolga; Kalemci, Emrah; Tomsick, John A.

    2012-06-15

    We present the optical/infrared (O/IR) light curve of the black hole X-ray binary GX 339-4 collected at the SMARTS 1.3 m telescope from 2002 to 2010. During this time the source has undergone numerous state transitions including hard-to-soft state transitions when we see large changes in the near-IR flux accompanied by modest changes in optical flux, and three rebrightening events in 2003, 2005, and 2007 after GX 339-4 transitioned from the soft state to the hard. All but one outburst show similar behavior in the X-ray hardness-intensity diagram. We show that the O/IR colors follow two distinct tracks that reflect either the hard or soft X-ray state of the source. Thus, either of these two X-ray states can be inferred from O/IR observations alone. From these correlations we have constructed spectral energy distributions of the soft and hard states. During the hard state, the near-IR data have the same spectral slope as simultaneous radio data when GX 339-4 was in a bright optical state, implying that the near-IR is dominated by a non-thermal source, most likely originating from jets. Non-thermal emission dominates the near-IR bands during the hard state at all but the faintest optical states, and the fraction of non-thermal emission increases with increasing optical brightness. The spectral slope of the optical bands indicate that a heated thermal source is present during both the soft and hard X-ray states, even when GX 339-4 is at its faintest optical state. We have conducted a timing analysis of the light curve for the hard and soft states and find no evidence of a characteristic timescale within the range of 4-230 days.

  15. NEW CONSTRAINTS ON THE BLACK HOLE LOW/HARD STATE INNER ACCRETION FLOW WITH NuSTAR

    SciTech Connect

    Miller, J. M.; King, A. L.; Tomsick, J. A.; Boggs, S. E.; Bachetti, M.; Wilkins, D.; Christensen, F. E.; Craig, W. W.; Fabian, A. C.; Kara, E.; Grefenstette, B. W.; Harrison, F. A.; Hailey, C. J.; Stern, D. K; Zhang, W. W.

    2015-01-20

    We report on an observation of the Galactic black hole candidate GRS 1739–278 during its 2014 outburst, obtained with NuSTAR. The source was captured at the peak of a rising ''low/hard'' state, at a flux of ∼0.3 Crab. A broad, skewed iron line and disk reflection spectrum are revealed. Fits to the sensitive NuSTAR spectra with a number of relativistically blurred disk reflection models yield strong geometrical constraints on the disk and hard X-ray ''corona''. Two models that explicitly assume a ''lamp post'' corona find its base to have a vertical height above the black hole of h=5{sub −2}{sup +7} GM/c{sup 2} and h = 18 ± 4 GM/c {sup 2} (90% confidence errors); models that do not assume a ''lamp post'' return emissivity profiles that are broadly consistent with coronae of this size. Given that X-ray microlensing studies of quasars and reverberation lags in Seyferts find similarly compact coronae, observations may now signal that compact coronae are fundamental across the black hole mass scale. All of the models fit to GRS 1739–278 find that the accretion disk extends very close to the black hole—the least stringent constraint is r{sub in}=5{sub −4}{sup +3} GM/c{sup 2}. Only two of the models deliver meaningful spin constraints, but a = 0.8 ± 0.2 is consistent with all of the fits. Overall, the data provide especially compelling evidence of an association between compact hard X-ray coronae and the base of relativistic radio jets in black holes.

  16. Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre.

    PubMed

    Genzel, R; Schödel, R; Ott, T; Eckart, A; Alexander, T; Lacombe, F; Rouan, D; Aschenbach, B

    2003-10-30

    Recent measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* (refs 4, 5) at the Galactic Centre is a 3.6-million-solar-mass black hole. Sgr A* is remarkably faint in all wavebands other than the radio region, however, which challenges current theories of matter accretion and radiation surrounding black holes. The black hole's rotation rate is not known, and therefore neither is the structure of space-time around it. Here we report high-resolution infrared observations of Sgr A* that reveal 'quiescent' emission and several flares. The infrared emission originates from within a few milliarcseconds of the black hole, and traces very energetic electrons or moderately hot gas within the innermost accretion region. Two flares exhibit a 17-minute quasi-periodic variability. If the periodicity arises from relativistic modulation of orbiting gas, the emission must come from just outside the event horizon, and the black hole must be rotating at about half of the maximum possible rate.

  17. Microanatomy of Passerine hard-cornified tissues: beak and claw structure of the Black-capped Chickadee (Poecile atricapillus)

    USGS Publications Warehouse

    Van Hemert, Caroline R.; Handel, Colleen M.; Blake, J.; Swor, Rhonda; O'Hara, Todd M.

    2012-01-01

    The microanatomy of healthy beaks and claws in passerine birds has not been well described in the literature, despite the importance of these structures in avian life. Histological processing of hard-cornified tissues is notoriously challenging and only a few reports on effective techniques have been published. An emerging epizootic of beak deformities among wild birds in Alaska and the Pacific Northwest region of North America recently highlighted the need for additional baseline information about avian hard-cornified structures. In this study, we examine the beak and claw of the Black-capped Chickadee (Poecile atricapillus), a common North American passerine that is affected by what has been described as “avian keratin disorder.” We use light and scanning electron microscopy and high-magnification radiography to document the healthy microanatomy of these tissues and identify features of functional importance. We also describe detailed methods for histological processing of avian hard-cornified structures and discuss the utility of special stains. Results from this study will assist in future research on the functional anatomy and pathology of hard-cornified structures and will provide a necessary reference for ongoing investigations of avian keratin disorder in Black-capped Chickadees and other wild passerine species.

  18. Microanatomy of passerine hard-cornified tissues: Beak and claw structure of the black-capped chickadee (Poecile atricapillus)

    USGS Publications Warehouse

    Van Hemert, C.; Handel, C.M.; Blake, J.E.; Swor, R.M.; O'Hara, T. M.

    2012-01-01

    The microanatomy of healthy beaks and claws in passerine birds has not been well described in the literature, despite the importance of these structures in avian life. Histological processing of hard-cornified tissues is notoriously challenging and only a few reports on effective techniques have been published. An emerging epizootic of beak deformities among wild birds in Alaska and the Pacific Northwest region of North America recently highlighted the need for additional baseline information about avian hard-cornified structures. In this study, we examine the beak and claw of the Black-capped Chickadee (Poecile atricapillus), a common North American passerine that is affected by what has been described as "avian keratin disorder." We use light and scanning electron microscopy and high-magnification radiography to document the healthy microanatomy of these tissues and identify features of functional importance. We also describe detailed methods for histological processing of avian hard-cornified structures and discuss the utility of special stains. Results from this study will assist in future research on the functional anatomy and pathology of hard-cornified structures and will provide a necessary reference for ongoing investigations of avian keratin disorder in Black-capped Chickadees and other wild passerine species. ?? 2011 Wiley Periodicals, Inc.

  19. Microanatomy of passerine hard-cornified tissues: beak and claw structure of the black-capped chickadee (Poecile atricapillus).

    PubMed

    Van Hemert, Caroline; Handel, Colleen M; Blake, John E; Swor, Rhonda M; O'Hara, Todd M

    2012-02-01

    The microanatomy of healthy beaks and claws in passerine birds has not been well described in the literature, despite the importance of these structures in avian life. Histological processing of hard-cornified tissues is notoriously challenging and only a few reports on effective techniques have been published. An emerging epizootic of beak deformities among wild birds in Alaska and the Pacific Northwest region of North America recently highlighted the need for additional baseline information about avian hard-cornified structures. In this study, we examine the beak and claw of the Black-capped Chickadee (Poecile atricapillus), a common North American passerine that is affected by what has been described as "avian keratin disorder." We use light and scanning electron microscopy and high-magnification radiography to document the healthy microanatomy of these tissues and identify features of functional importance. We also describe detailed methods for histological processing of avian hard-cornified structures and discuss the utility of special stains. Results from this study will assist in future research on the functional anatomy and pathology of hard-cornified structures and will provide a necessary reference for ongoing investigations of avian keratin disorder in Black-capped Chickadees and other wild passerine species.

  20. Black Arsenic-Phosphorus: Layered Anisotropic Infrared Semiconductors with Highly Tunable Compositions and Properties

    NASA Astrophysics Data System (ADS)

    Liu, Bilu; Zhou, Chongwu

    2D layered materials with diverse properties have attracted significant interest in the past decade. The layered materials discovered so far have covered a wide, yet discontinuous electromagnetic spectral range from semimetallic graphene, insulating boron nitride, to semiconductors with bandgaps from middle infrared to visible light. Here, we introduce new layered semiconductors, black arsenic-phosphorus (b-AsP), with highly tunable chemical compositions and electronic and optical properties. Transport and infrared absorption studies demonstrate the semiconducting nature of b-AsP with tunable bandgaps, ranging from 0.3 to 0.15 eV. These bandgaps fall into long-wavelength infrared (LWIR) regime and cannot be readily reached by other layered materials. Moreover, polarization-resolved infrared absorption and Raman studies reveal in-plane anisotropic properties of b-AsP. This family of layered b-AsP materials extend the electromagnetic spectra covered by 2D layered materials to the LWIR regime, and may find unique applications for future all 2D layered material based devices. Ref. Liu, B., et al., Black Arsenic-Phosphorus: Layered Anisotropic Infrared Semiconductors with Highly Tunable Compositions and Properties. Adv. Mater., 2015, 27, 4423-4429.

  1. James Q. Qilson on John Ogbu: Convincing Black Students that Studying Hard Is Not "Acting White."

    ERIC Educational Resources Information Center

    Wilson, James Q.

    2003-01-01

    Reflects on John Ogbu's explanations for the wide academic achievement gap between black and white students, explaining Ogbu's view that black students' poor performance reflects their incorporation of the beliefs of white society and their subsequent academic self-doubt leads to self-elimination. Notes the importance of telling black children…

  2. Particle contamination from Martin Optical Black. [in design of barrel baffle of Infrared Astronomical Satellite

    NASA Technical Reports Server (NTRS)

    Young, P. J.; Noll, R.; Andreozzi, L.; Hope, J.

    1981-01-01

    The design of the barrel baffle of the Infrared Astronomical Satellite (IRAS) Optical Subsystem to minimize production of particulate contamination is described. The configuration of the 50-inch long, 28.5-inch diameter baffle required pop-rivet assembly after coating with Martin Optical Black for stray light suppression. An experiment to determine the contamination produced at assembly led to the modification of the baffle construction to preclude such damage to the coated surfaces.

  3. Particle contamination from Martin Optical Black. [in design of barrel baffle of Infrared Astronomical Satellite

    NASA Technical Reports Server (NTRS)

    Young, P. J.; Noll, R.; Andreozzi, L.; Hope, J.

    1981-01-01

    The design of the barrel baffle of the Infrared Astronomical Satellite (IRAS) Optical Subsystem to minimize production of particulate contamination is described. The configuration of the 50-inch long, 28.5-inch diameter baffle required pop-rivet assembly after coating with Martin Optical Black for stray light suppression. An experiment to determine the contamination produced at assembly led to the modification of the baffle construction to preclude such damage to the coated surfaces.

  4. Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Electro-optical Applications

    DTIC Science & Technology

    2010-05-01

    BLISS ATTN RDRL SE E T BOWER ATTN RDRL SED E M LITZ ATTN RDRL SED P A LELIS ATTN RDRL SED P B MORGAN ATTN RDRL SED P K JONES...Meissner, and Priyalal Wijewarnasuriya ARL -TR-5202 May 2010 Approved for public release...Research Laboratory Adelphi, MD 20783-1197 ARL -TR-5202 May 2010 Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared

  5. SUZAKU OBSERVATION OF THE BLACK HOLE CANDIDATE MAXI J1836-194 IN A HARD/INTERMEDIATE SPECTRAL STATE

    SciTech Connect

    Reis, R. C.; Miller, J. M.; Reynolds, M. T.; Fabian, A. C.; Walton, D. J.

    2012-05-20

    We report on a Suzaku observation of the newly discovered X-ray binary MAXI J1836-194. The source is found to be in the hard/intermediate spectral state and displays a clear and strong relativistically broadened iron emission line. We fit the spectra with a variety of phenomenological, as well as physically motivated disk reflection models, and find that the breadth and strength of the iron line are always characteristic of emission within a few gravitational radii around a black hole. This result is independent of the continuum used and strongly points toward the central object in MAXI J1836-194 being a stellar mass black hole rotating with a spin of a = 0.88 {+-} 0.03 (90% confidence). We discuss this result in the context of spectral state definitions, physical changes (or lack thereof) in the accretion disk, and on the potential importance of the accretion disk corona in state transitions.

  6. Theoretical analysis of tablet hardness prediction using chemoinformetric near-infrared spectroscopy.

    PubMed

    Tanabe, Hideaki; Otsuka, Kuniko; Otsuka, Makoto

    2007-07-01

    In order to clarify the theoretical basis of the variability in the measurement of tablet hardness by compression pressure, NIR spectroscopic methods were used to predict tablet hardness of the formulations. Tablets (200 mg, 8 mm in diameter) consisting of berberine chloride, lactose, and potato starch were formed at various compression pressures (59, 78, 98, 127, 195 MPa). The hardness and the distribution of micropores were measured. The reflectance NIR spectra of various compressed tablets were used as a calibration set to establish a calibration model to predict tablet hardness by principal component regression (PCR) analysis. The distribution of micropores was shifted to a smaller pore size with increasing compression pressure. The total pore volume of tablets decreased as the compression pressure increased. The hardness increased as the compression pressure increased. The hardness could be predicted using a calibration model consisting of 7 principal components (PCs) obtained by PCR. The relationship between the predicted and the actual hardness values exhibited a straight line, an R(2) of 0.925. In order to understand the theoretical analysis (scientific background) of calibration models used to evaluate tablet hardness, the standard error of cross validation (SEV) values, the loading vectors of each PC and the regression vector were investigated. The result obtained with the calibration models for hardness suggested that the regression vector might involve physical and chemical factors. In contrast, the porosity could be predicted using a calibration model composed of 2 PCs. The relationship between the predicted and the actual total pore volume showed a straight line with R(2) = 0.801. The regression vector of the total pore volume might be due to physical factors.

  7. Prediction of drug content and hardness of intact tablets using artificial neural network and near-infrared spectroscopy.

    PubMed

    Chen, Y; Thosar, S S; Forbess, R A; Kemper, M S; Rubinovitz, R L; Shukla, A J

    2001-08-01

    The purpose of this study was to predict drug content and hardness of intact tablets using artificial neural networks (ANN) and near-infrared spectroscopy (NIRS). Tablets for the drug content study were compressed from mixtures of Avicel PH-101, 0.5% magnesium stearate, and varying concentrations (0%, 1%, 2%, 5%, 10%, 20%, and 40% w/w) of theophylline. Tablets for the hardness study were compressed from mixtures of Avicel PH-101 and 0.5% magnesium stearate at varying compression forces ranging from 0.4 to 1 ton. An Intact Analyzer was used to obtain near infrared spectra from the tablets with varying drug contents, whereas a Rapid Content Analyzer (RCA) was used to obtain spectral data from the tablets with varying hardness. Two sets of tablets from each batch (i.e., tablets with varying drug content and hardness) were randomly selected. One set of tablets was used to generate appropriate calibration models, while the other set was used as the unknown (test) set. A total of 10 ANN calibration models (5 each with 10 and 160 inputs at appropriate wavelengths) and five separate 4-factor partial least squares (PLS) calibration models were generated to predict drug contents of the test tablets from the spectral data. For the prediction of tablet hardness, two ANN calibration models (one each with 10 and 160 inputs) and two 4-factor PLS calibration models were generated and used to predict the hardness of test tablets. The PLS calibration models were generated using Vision software. Prediction of drug contents of test tablets using the ANN calibration models generated with 10 inputs was significantly better than the prediction obtained with the ANN calibration models with 160 inputs. For tablets with low drug concentrations (less than or equal to 2% w/w) prediction of drug content was better with either of the two ANN calibration models than with the PLS calibration models. However, prediction of drug contents of tablets with greater than or equal to 5% w/w drug was

  8. Scattering characteristics of Martin Black at 118 microns. [from Infrared Astronomical Satellite telescope baffles

    NASA Technical Reports Server (NTRS)

    Brooks, L. D.; Hubbs, J. E.; Bartell, F. O.; Wolfe, W. L.

    1982-01-01

    BRDF (bidirectional reflectance distribution function) values for 0.000118 m radiation at different angles of incidence and different scattering angles from the Infrared Astronomical Satellite telescope baffle coated with Martin Black are presented. Data from scatterometer experiments are collected and the BRDF and beta - beta sub 0 (sin theta sub s - sin theta sub 0) values are calculated based on the geometry, the voltage readings, the attenuators in the beam, and the calculated reference levels. A composite curve of forward and backward scattering data for several angles of incidence shows a peak near the specular direction (beta - beta sub 0 = 0), which is the instrument profile reduced by the 20% specular reflection of the Martin Black. The nonspecular part of the reflectivity indicates the slightly specular but largely Lambertian character of the coating. Data for the specular reflectivity as a function of the incidence angle unexpectedly shows a decrease in the specular reflectance with increasing angle of incidence.

  9. Differentiating ``hard'' from ``soft'' woods using Fourier transform infrared and Fourier transform spectroscopy

    NASA Astrophysics Data System (ADS)

    Evans, P. A.

    The Fourier transform Raman and Fourier transform infrared spectra of six soft- and six hardwoods are presented in this paper. In contrast to conventional Raman spectroscope using visible excitation, the use of a near-infrared laser induced far less fluorescence, and this enabled high quality spectra to be obtained. It is shown that it is possible to differentiate between the two types of wood using both techniques, and the reasons for these differences are discussed.

  10. BAT AGN Spectroscopic Survey - IV: Near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray Emission

    NASA Astrophysics Data System (ADS)

    Lamperti, Isabella; Koss, Michael; Trakhtenbrot, Benny; Schawinski, Kevin; Ricci, Claudio; Oh, Kyuseok; Landt, Hermine; Riffel, Rogério; Rodríguez-Ardila, Alberto; Gehrels, Neil; Harrison, Fiona; Masetti, Nicola; Mushotzky, Richard; Treister, Ezequiel; Ueda, Yoshihiro; Veilleux, Sylvain

    2017-01-01

    We provide a comprehensive census of the near-Infrared (NIR, 0.8-2.4 μm) spectroscopic properties of 102 nearby (z < 0.075) active galactic nuclei (AGN), selected in the hard X-ray band (14-195 keV) from the Swift-Burst Alert Telescope (BAT) survey. With the launch of the James Webb Space Telescope this regime is of increasing importance for dusty and obscured AGN surveys. We measure black hole masses in 68% (69/102) of the sample using broad emission lines (34/102) and/or the velocity dispersion of the Ca II triplet or the CO band-heads (46/102). We find that emission line diagnostics in the NIR are ineffective at identifying bright, nearby AGN galaxies because ([Fe II] 1.257μm/Paβ and H2 2.12μm/Brγ) identify only 25% (25/102) as AGN with significant overlap with star forming galaxies and only 20% of Seyfert 2 have detected coronal lines (6/30). We measure the coronal line emission in Seyfert 2 to be weaker than in Seyfert 1 of the same bolometric luminosity suggesting obscuration by the nuclear torus. We find that the correlation between the hard X-ray and the [Fe II] coronal line luminosity is significantly better than with the [O III] λ5007 luminosity. Finally, we find 3/29 galaxies (10%) that are optically classified as Seyfert 2 show broad emission lines in the NIR. These AGN have the lowest levels of obscuration among the Seyfert 2s in our sample (log NH < 22.43 cm-2), and all show signs of galaxy-scale interactions or mergers suggesting that the optical broad emission lines are obscured by host galaxy dust.

  11. BAT AGN Spectroscopic Survey - IV: Near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray Emission

    NASA Astrophysics Data System (ADS)

    Lamperti, Isabella; Koss, Michael; Trakhtenbrot, Benny; Schawinski, Kevin; Ricci, Claudio; Oh, Kyuseok; Landt, Hermine; Riffel, Rogério; Rodríguez-Ardila, Alberto; Gehrels, Neil; Harrison, Fiona; Masetti, Nicola; Mushotzky, Richard; Treister, Ezequiel; Ueda, Yoshihiro; Veilleux, Sylvain

    2017-05-01

    We provide a comprehensive census of the near-infrared (NIR, 0.8-2.4 μm) spectroscopic properties of 102 nearby (z < 0.075) active galactic nuclei (AGN), selected in the hard X-ray band (14-195 keV) from the Swift-Burst Alert Telescope survey. With the launch of the James Webb Space Telescope, this regime is of increasing importance for dusty and obscured AGN surveys. We measure black hole masses in 68 per cent (69/102) of the sample using broad emission lines (34/102) and/or the velocity dispersion of the Ca ii triplet or the CO band-heads (46/102). We find that emission-line diagnostics in the NIR are ineffective at identifying bright, nearby AGN galaxies because [Fe ii] 1.257 μm/Paβ and H2 2.12 μm/Brγ identify only 25 per cent (25/102) as AGN with significant overlap with star-forming galaxies and only 20 per cent of Seyfert 2 have detected coronal lines (6/30). We measure the coronal line emission in Seyfert 2 to be weaker than in Seyfert 1 of the same bolometric luminosity suggesting obscuration by the nuclear torus. We find that the correlation between the hard X-ray and the [Si vi] coronal line luminosity is significantly better than with the [O iii] λ5007 luminosity. Finally, we find 3/29 galaxies (10 per cent) that are optically classified as Seyfert 2 show broad emission lines in the NIR. These AGN have the lowest levels of obscuration among the Seyfert 2s in our sample (log NH < 22.43 cm-2), and all show signs of galaxy-scale interactions or mergers suggesting that the optical broad emission lines are obscured by host galaxy dust.

  12. Effect of heat treatment on the far-infrared emission spectra and fine structures of black tourmaline.

    PubMed

    Meng, Junping; Liang, Jinsheng; Liu, Jie; Ding, Yan; Gan, Kun

    2014-05-01

    Mineral black tourmaline powders were heat-treated at different temperatures. Their crystal structure was studied by X-ray diffractometer. Their infrared absorption and emission spectra before and after the heat treatment were analyzed by the Fourier transform infrared spectrometer. The corresponding fine structures were discussed in detail. The results showed that the powders possessed higher infrared emissivity at the band where they showed stronger infrared absorption. However, there is no certain correlation between the peak intensity of infrared absorption and emissivity values at the same frequency. Because of the crystal shrinkage of c-axis, the electronic transitions were stimulated between different energy levels, and the abilities of infrared absorption and emission were enhanced with increasing the temperature of heat treatment.

  13. Oxygen impact on the electronic and vibrational properties of black phosphorus probed by synchrotron infrared nanospectroscopy

    NASA Astrophysics Data System (ADS)

    Grasseschi, D.; Bahamon, D. A.; Maia, F. C. B.; Castro Neto, A. H.; Freitas, R. O.; de Matos, C. J. S.

    2017-09-01

    Black phosphorus (BP) is a layered crystalline structure presenting a thickness-tunable direct bandgap and a high charge carrier mobility, with, therefore, enormous interest to photonics, optoelectronics and electronics. However, BP’s high susceptibility to oxidation when exposed to ambient conditions is a critical challenge for its implementation into functional systems. Here, we investigate the degradation of BP flakes exposed to various environmental conditions by synchrotron infrared nanospectroscopy (SINS). As a near-field based technique, SINS provides sub-diffractional mid-infrared images and spectra from nano-sized domains. Supported by density functional theory (DFT) calculations, our SINS spectra reveal the formation of nanoscale PO x domains, with x between 0.5 and 1, and a 100 meV red shift in the bandgap of flakes exposed to air for a few minutes. On the other hand, exposure to air for 24 h led to the preferential formation of H3PO4, with complete removal of the electronic transitions from the mid-infrared spectral window, while a long (1 month) exposure to low O2 levels mainly led to the formation of P4O8 and P4O9 species. The SINS analysis allows correlating the morphology of oxidized samples to the oxide type, thus, contributing to a comprehensive characterization of the BP degradation process.

  14. Long-Wave Infrared Thermophotonic Imaging of Demineralization in Dental Hard Tissue

    NASA Astrophysics Data System (ADS)

    Ojaghi, A.; Parkhimchyk, A.; Tabatabaei, N.

    2016-08-01

    Dental caries remains the most prevalent chronic disease in both children and adults worldwide. To address this prevalence through disease prevention and management, dentists need tools capable of detecting caries at early stages of formation. Looking into the physics of light propagation in teeth, this study presents a clinically and commercially viable platform technology for thermophotonic detection of early dental caries using an inexpensive long-wavelength infrared (LWIR; 8 μm to 14 μm) camera. The developed system incorporates intensity-modulated light to generate a thermal-wave field inside enamel and uses the subsequent infrared emission of the thermal-wave field to detect early caries. It was found that the greater light absorption at caries sites shifts the thermal-wave field centroid, providing contrast between early caries and intact enamel. Use of LWIR detection band in dental samples is novel and beneficial over the conventional mid-wavelength infrared band (3 μm to 5 μm) as it suppresses the masking effect of the instantaneous radiative emission from subsurface features due to the minimal transmittance of enamel in the LWIR band. The efficacy of the LWIR system is verified though experiments carried out on nonbiological test samples as well as on teeth with natural and artificially induced caries. The results suggest that the developed LWIR technology is an affordable early dental caries detection system suitable for commercialization/translation to Dentistry.

  15. A `high-hard' outburst of the black hole X-ray binary GS 1354-64

    NASA Astrophysics Data System (ADS)

    Koljonen, K. I. I.; Russell, D. M.; Corral-Santana, J. M.; Armas Padilla, M.; Muñoz-Darias, T.; Lewis, F.; Coriat, M.; Bauer, F. E.

    2016-07-01

    We study in detail the evolution of the 2015 outburst of GS 1354-64 (BW Cir) at optical, UV and X-ray wavelengths using Faulkes Telescope South/Las Cumbres Observatory Global Telescope Network, Small & Moderate Aperture Research Telescope System and Swift. The outburst was found to stay in the hard X-ray state, albeit being anomalously luminous with a peak luminosity of LX > 0.15 LEdd, which could be the most luminous hard state observed in a black hole X-ray binary. We found that the optical/UV emission is tightly correlated with the X-ray emission, consistent with accretion disc irradiation and/or a jet producing the optical emission. The X-ray spectra can be fitted well with a Comptonization model, and show softening towards the end of the outburst. In addition, we detect a QPO in the X-ray light curves with increasing centroid frequency during the peak and decay periods of the outburst. The long-term optical light curves during quiescence show a statistically significant, slow rise of the source brightness over the 7 years prior to the 2015 outburst. This behaviour as well as the outburst evolution at all wavelengths studied can be explained by the disc instability model with irradiation and disc evaporation/condensation.

  16. A Good Hard Look at Growing Supermassive Black Holes in the Distant Universe

    NASA Astrophysics Data System (ADS)

    Brandt, W. Niel; Chandra Deep Fields Team

    2017-01-01

    Sensitive cosmic X-ray surveys with the Chandra, XMM-Newton, and now NuSTAR observatories have revolutionized our ability to find and study distant active galactic nuclei (AGNs), the main sites of supermassive black hole growth in the Universe. I will describe some of the resulting discoveries about the demographics, physics, and ecology of distant AGNs with an emphasis on the deepest Chandra surveys, the Chandra Deep Fields. Some specific topics covered will include (1) robust X-ray spectral and variability characterization of the AGNs producing most of cosmic accretion power; (2) the demographics of AGNs in the first galaxies as revealed by direct detection and stacking; (3) AGN/galaxy interactions as investigated via the host properties of X-ray AGNs; and (4) the cosmic balance of power between supermassive black holes and stars. I will also briefly describe other remarkable discoveries coming from the deepest X-ray surveys; e.g., measurements of the evolving X-ray binary populations of normal and starburst galaxies. I will end by discussing some key outstanding questions and new observations and missions aiming to answer them.

  17. On the physical and geometrical properties responsible for the highly absorbing nature of black materials in the infrared

    NASA Astrophysics Data System (ADS)

    Meier, Steven Robert

    Black surfaces are of paramount importance in the design of terrestrial and space-borne optical systems. Optical designers can choose from a variety of black materials to suppress reflected and scattered stray light. Among these applications are the suppression of unwanted reflection or scattering of light in optical systems, solar collectors, blackbody absorbers, thermal insulators, telescope housing and baffles where stray light reduction is vital, and cold stops and light shields for infrared detectors. The physical mechanisms responsible for understanding the highly absorbing nature of black materials in the infrared spectral region are investigated in this dissertation. We present experimental data on the optical, surface, and constituent properties of black materials. In addition, we developed unique optical instrumentation to characterize the hemispherical reflectance and scattering properties of these materials as a function of incident angle and state of polarization. We compared the experimental data to theoretical rough surface scattering models to understand the absorption mechanisms of these black materials and found good agreement. Furthermore, results from a new, highly absorbing black material in the infrared wavelength regime, known as carbon aerogels, are presented and shown to be superior or equivalent to existing black materials used by optical designers. In addition, we presented a new cylindrical-spherical cavity enclosure and calculated the apparent emissivity along the bounding surfaces of this new cavity enclosure. To our knowledge, this was the first calculation of the apparent emissivity for a cavity enclosure with obscuration. Finally, we proposed several improvements for each individual black material in order to achieve even higher absorption levels.

  18. Nano-imaging in the black-body infrared near-field.

    NASA Astrophysics Data System (ADS)

    Jones, Andrew C.; Raschke, Markus B.

    2010-03-01

    In order to probe material properties on the nanoscale, Scanning Near-field Optical Microscopy (SNOM) traditionally relies on the use of external far-field light sources. Recent experiments have demonstrated the alternative use of the evanescent thermal black-body radiation in scattering-SNOM [1]. Here, we explore the use of both heated samples and heated probe tips for scattering type SNOM in combination with Fourier transform infrared spectroscopy (FTIR) of the scattered thermal blackbody near-field radiation of IR nano-antennas and surface phonon excitations. We relate the observed and theoretically expected signal strength with the resonantly enhanced electromagnetic near-field density of states. Our result illustrates the potential as well as the limitations of the use of thermal evanescent fields for nano-imaging. [1] De Wilde, Y. et al. Nature. 444:740-743 (2006)

  19. High-brightness table-top hard X-ray source driven by sub-100-femtosecond mid-infrared pulses

    NASA Astrophysics Data System (ADS)

    Weisshaupt, Jannick; Juvé, Vincent; Holtz, Marcel; Ku, Shinan; Woerner, Michael; Elsaesser, Thomas; Ališauskas, Skirmantas; Pugžlys, Audrius; Baltuška, Andrius

    2014-12-01

    Ultrafast structural dynamics in the condensed phase represents a key topic of current physics, chemistry and materials science. Femtosecond hard X-ray pulses are important structure probes that have been applied in time-resolved X-ray absorption and diffraction. Optical pump/X-ray probe schemes with compact laser-driven table-top sources have allowed for tiny changes of diffracted intensity to be measured with X-ray photon statistics, which has set the ultimate sensitivity limit. To address the strong quest for a higher X-ray flux, here we present the first hard X-ray plasma source driven by intense mid-infrared sub-100-fs pulses at 3.9 μm. The comparably long optical period allows for accelerating electrons from the Cu target to very high kinetic energies and for generating a characteristic Kα flux of 109 photons per pulse, 25 times more than with our 800 nm driver. Theoretical simulations account for the experimental results in a wide range of driving fields and predict a further enhancement of X-ray flux.

  20. Hard X-ray emission of the luminous infrared galaxy NGC 6240 as observed by NuSTAR

    NASA Astrophysics Data System (ADS)

    Puccetti, S.; Comastri, A.; Bauer, F. E.; Brandt, W. N.; Fiore, F.; Harrison, F. A.; Luo, B.; Stern, D.; Urry, C. M.; Alexander, D. M.; Annuar, A.; Arévalo, P.; Baloković, M.; Boggs, S. E.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Koss, M. J.; La Massa, S.; Marinucci, A.; Ricci, C.; Walton, D. J.; Zappacosta, L.; Zhang, W.

    2016-01-01

    We present a broadband (~0.3-70 keV) spectral and temporal analysis of NuSTAR observations of the luminous infrared galaxy NGC 6240 combined with archival Chandra, XMM-Newton, and BeppoSAX data. NGC 6240 is a galaxy in a relatively early merger state with two distinct nuclei separated by ~1.̋5. Previous Chandra observations resolved the two nuclei and showed that they are both active and obscured by Compton-thick material. Although they cannot be resolved by NuSTAR, we were able to clearly detect, for the first time, both the primary and the reflection continuum components thanks to the unprecedented quality of the NuSTAR data at energies >10 keV. The NuSTAR hard X-ray spectrum is dominated by the primary continuum piercing through an absorbing column density which is mildly optically thick to Compton scattering (τ ≃ 1.2, NH ~ 1.5 × 1024 cm-2). We detect moderately hard X-ray (>10 keV) flux variability up to 20% on short (15-20 ks) timescales. The amplitude of the variability is largest at ~30 keV and is likely to originate from the primary continuum of the southern nucleus. Nevertheless, the mean hard X-ray flux on longer timescales (years) is relatively constant. Moreover, the two nuclei remain Compton-thick, although we find evidence of variability in the material along the line of sight with column densities NH ≤ 2 × 1023 cm-2 over long (~3-15 yr) timescales. The observed X-ray emission in the NuSTAR energy range is fully consistent with the sum of the best-fit models of the spatially resolved Chandra spectra of the two nuclei.

  1. Near-infrared absorptance enhancement and device application of nanostructured black silicon fabricated by metal-assist chemical etching

    NASA Astrophysics Data System (ADS)

    Huang, Lieyun; Zhong, Hao; Liao, Naiman; Long, Fei; Guo, Guohui; Li, Wei

    2016-11-01

    We use metal-assist chemical etching (MCE) method to fabricate nanostructured black silicon on the surface of C-Si. In our MCE process, a chemical reduction reaction of silver cation (Ag+) will happen on the surface of silicon substrate, and at the same time the silicon atoms around Ag particles are oxidized and dissolved, generating nanopores and finally forming a layer called black silicon on the top of the substrates. The nanopores have diameter and depth of about 400 nm and 2 μm, respectively. Furthermore, these modified surfaces show higher light absorptance in near-infrared range (800 to 2500 nm) compared to that of C-Si with polished surfaces, and the maximum light absorptance increases significantly up to 95% in the wavelength region of 400 to 2500 nm. The Si-PIN photoelectronic detector based on this type of black silicon, in which the black silicon layer is directly set as the photosensitive surface, has a substantial increase in responsivity with about 80 nm red shift of peak responsivity, particularly at near-infrared wavelengths, rising to 0.57 A/W at 1060 nm and 0.37 A/W at 1100 nm, respectively. Our recent novel results clearly indicate that nanostructured black silicon made by MCE has a potential application in near-infrared photoelectronic detectors.

  2. Infrared spectroscopy of laser-irradiated dental hard tissues using the Advanced Light Source

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Breunig, Thomas

    2001-04-01

    FTIR spectroscopy used in the specular reflectance mode is well suited for resolving thermally induced changes in dental hard tissue as a result of laser irradiation. High spatial resolution is achievable with a high brightness synchrotron radiation source such as the ALS at Lawrence Berkeley National Laboratory. IR spectra of modified enamel were acquired after laser ablation using several laser wavelengths from the UV to the mid-IR. Specific areas of laser ablation craters were probed non-destructively with 10-micrometers spatial resolution. The chemical composition of the crater walls deviates markedly from that of hydroxyapatite after Er:YAG and CO2 laser irradiation without added water. New mineral phases were resolved that have not been previously observed using conventional IR spectroscopy.

  3. Room temperature high-detectivity mid-infrared photodetectors based on black arsenic phosphorus

    PubMed Central

    Long, Mingsheng; Gao, Anyuan; Wang, Peng; Xia, Hui; Ott, Claudia; Pan, Chen; Fu, Yajun; Liu, Erfu; Chen, Xiaoshuang; Lu, Wei; Nilges, Tom; Xu, Jianbin; Wang, Xiaomu; Hu, Weida; Miao, Feng

    2017-01-01

    The mid-infrared (MIR) spectral range, pertaining to important applications, such as molecular “fingerprint” imaging, remote sensing, free space telecommunication, and optical radar, is of particular scientific interest and technological importance. However, state-of-the-art materials for MIR detection are limited by intrinsic noise and inconvenient fabrication processes, resulting in high-cost photodetectors requiring cryogenic operation. We report black arsenic phosphorus–based long-wavelength IR photodetectors, with room temperature operation up to 8.2 μm, entering the second MIR atmospheric transmission window. Combined with a van der Waals heterojunction, room temperature–specific detectivity higher than 4.9 × 109 Jones was obtained in the 3- to 5-μm range. The photodetector works in a zero-bias photovoltaic mode, enabling fast photoresponse and low dark noise. Our van der Waals heterojunction photodetectors not only exemplify black arsenic phosphorus as a promising candidate for MIR optoelectronic applications but also pave the way for a general strategy to suppress 1/f noise in photonic devices. PMID:28695200

  4. Mid-infrared-selected quasars. I. Virial black hole mass and eddington ratios

    SciTech Connect

    Dai, Y. Sophia; Elvis, Martin; Fazio, Giovanni G.; Huang, Jia-Sheng; Wilkes, Belinda J.; Bergeron, Jacqueline; Omont, Alain; Willmer, Christopher N. A.; Papovich, Casey

    2014-08-20

    We provide a catalog of 391 mid-infrared-selected (MIR; 24 μm) broad-emission-line (BEL; type 1) quasars in the 22 deg{sup 2} SWIRE Lockman Hole field. This quasar sample is selected in the MIR from Spitzer MIPS with S {sub 24} > 400 μJy, jointly with an optical magnitude limit of r (AB) < 22.5 for broad line identification. The catalog is based on MMT and Sloan Digital Sky Survey (SDSS) spectroscopy to select BEL quasars, extending the SDSS coverage to fainter magnitudes and lower redshifts, and recovers a more complete quasar population. The MIR-selected quasar sample peaks at z ∼ 1.4 and recovers a significant and constant (20%) fraction of extended objects with SDSS photometry across magnitudes, which were not included in the SDSS quasar survey dominated by point sources. This sample also recovers a significant population of z < 3 quasars at i > 19.1. We then investigate the continuum luminosity and line profiles of these MIR quasars, and estimate their virial black hole masses and the Eddington ratios. The supermassive black hole mass shows evidence of downsizing, although the Eddington ratios remain constant at 1 < z < 4. Compared to point sources in the same redshift range, extended sources at z < 1 show systematically lower Eddington ratios. The catalog and spectra are publicly available online.

  5. A Near Infrared Light Triggered Hydrogenated Black TiO2 for Cancer Photothermal Therapy.

    PubMed

    Ren, Wenzhi; Yan, Yong; Zeng, Leyong; Shi, Zhenzhi; Gong, An; Schaaf, Peter; Wang, Dong; Zhao, Jinshun; Zou, Baobo; Yu, Hongsheng; Chen, Ge; Brown, Eric Michael Bratsolias; Wu, Aiguo

    2015-07-15

    White TiO2 nanoparticles (NPs) have been widely used for cancer photodynamic therapy based on their ultraviolet light-triggered properties. To date, biomedical applications using white TiO2 NPs have been limited, since ultraviolet light is a well-known mutagen and shallow penetration. This work is the first report about hydrogenated black TiO2 (H-TiO2 ) NPs with near infrared absorption explored as photothermal agent for cancer photothermal therapy to circumvent the obstacle of ultraviolet light excitation. Here, it is shown that photothermal effect of H-TiO2 NPs can be attributed to their dramatically enhanced nonradiative recombination. After polyethylene glycol (PEG) coating, H-TiO2 -PEG NPs exhibit high photothermal conversion efficiency of 40.8%, and stable size distribution in serum solution. The toxicity and cancer therapy effect of H-TiO2 -PEG NPs are relative systemically evaluated in vitro and in vivo. The findings herein demonstrate that infrared-irradiated H-TiO2 -PEG NPs exhibit low toxicity, high efficiency as a photothermal agent for cancer therapy, and are promising for further biomedical applications.

  6. Dichotomy Between Black Hole and Neutron Star Accretion: Effect of Hard Surface

    NASA Astrophysics Data System (ADS)

    Dhang, Prasun; Mukhopadhyay, Banibrata; Sharma, Prateek

    2016-07-01

    Estimates of accretion rate on to compact objects have been explored based on the well-known, spherically symmetric, inviscid, steady-state solution given by Bondi. This solution assumes that there is a sink of mass at the center -- which in case of a black hole (BH) corresponds to the advection of matter across the event horizon. Other stars, such as a neutron star (NS), have surfaces and hence the infalling matter has to come to rest at the surface. We study the initial value problem in which the matter distribution is uniform and at rest at time t=0 with different inner radial boundary conditions for BHs and NSs: inflow boundary condition valid for BHs; and reflective or settling boundary condition for NSs. We obtain a similarity solution for the flow with inner inflow and reflective boundary conditions (assuming a cold ambient medium) and compare with numerical simulations of the Euler equations. One-dimensional simulations show the formation of an outward propagating and a standing shock in NS system for reflective and settling boundary conditions respectively. Two-dimensional simulations show that both these flows are unstable (locally to convection and globally to a standing shock instability). Numerical simulations show that in steady state, spherical accretion rate on to a NS for reflective boundary condition is suppressed by orders of magnitude compared to that on to a BH.

  7. The evolution of the disc variability along the hard state of the black hole transient GX 339-4

    NASA Astrophysics Data System (ADS)

    De Marco, B.; Ponti, G.; Muñoz-Darias, T.; Nandra, K.

    2015-12-01

    We report on the analysis of hard-state power spectral density function (PSD) of GX 339-4 down to the soft X-ray band, where the disc significantly contributes to the total emission. At any luminosity probed, the disc in the hard state is intrinsically more variable than in the soft state. However, the fast decrease of disc variability as a function of luminosity, combined with the increase of disc intensity, causes a net drop of fractional variability at high luminosities and low energies, which reminds the well-known behaviour of disc-dominated energy bands in the soft state. The peak frequency of the high-frequency Lorentzian (likely corresponding to the high-frequency break seen in active galactic nuclei, AGN) scales with luminosity, but we do not find evidence for a linear scaling. In addition, we observe that this characteristic frequency is energy dependent. We find that the normalization of the PSD at the peak of the high-frequency Lorentzian decreases with luminosity at all energies, though in the soft band this trend is steeper. Together with the frequency shift, this yields quasi-constant high-frequency (5-20 Hz) fractional rms at high energies, with less than 10 per cent scatter. This reinforces previous claims suggesting that the high-frequency PSD solely scales with black hole mass. On the other hand, this constancy breaks down in the soft band (where the scatter increases to ˜30 per cent). This is a consequence of the additional contribution from the disc component, and resembles the behaviour of optical variability in AGN.

  8. A search for and characterization of the infrared emission from our galaxy's supermassive black hole

    NASA Astrophysics Data System (ADS)

    Hornstein, Seth David

    Ever since its discovery over 30 years ago, the radio source Sgr A* has been suspected of being associated with a supermassive black hole at the center of our Galaxy. Motivated by detections of extreme variability from Sgr A* at X-ray wavelengths, this dissertation uses a variety of observational and analysis techniques to analyze twelve years of infrared observations focused on the Galactic Center using the Keck 10 m telescopes. From speckle and natural guide star adaptive optics (AO) two-micron observations collected from 1995--2004, I present detection limits for Sgr A*'s IR emission from 36 individual observations. Collectively, these detection limits establish a dereddened upper limit of 19 mJy ( K obs = 14.73 mag) for three-hour outbursts occurring on the order of once per day and rule out the possibility of the outbursts being created by a model involving direct heating of thermal electrons unless additional restrictions are applied. Additionally, the single deepest image of the data set limits Sgr A*'s quiescent dereddened IR emission to be below 2 mJy ( K obs = 17.17 mag). With advancing technology, infrared detections of Sgr A* quickly emerged and revealed a variable source with similar outburst durations as the X-ray outbursts but occurring much more frequently. Using results from the Keck laser guide star AO system, I present the first time-series of Sgr A*'s broadband infrared color measurements throughout several outbursting events, including the largest detected IR outburst to date. These observations reveal that Sgr A*'s spectral index of a = -0.6 ± 0.2 ( F n 0( n a ) is independent of intensity, wavelength, time, or outburst. When coupled with X- ray observations showing a similar, and also constant, spectral index in the X- ray domain, these results imply that while the X-ray emission is most likely from synchrotron self-Compton scattering of the electron energy distribution responsible for the infrared emission, it cannot be coupled to electrons

  9. SWIFT AND RXTE OBSERVATIONS OF THE BLACK HOLE TRANSIENT GX 339-4 IN THE HARD STATE BETWEEN OUTBURSTS

    SciTech Connect

    Allured, Ryan; Tomsick, John A.; Kaaret, Philip; Yamaoka, Kazutaka E-mail: jtomsick@ssl.berkeley.edu E-mail: yamaoka@stelab.nagoya-u.ac.jp

    2013-09-10

    We use simultaneous Swift and RXTE observations of the black hole binary GX 339-4 to measure the inner radius of its accretion disk in the hard state down to 0.4% L{sub Edd} via modeling of the thermal disk emission and the relativistically broadened iron line. For the luminosity range covered in this work, our results rule out a significantly truncated disk at 100-1000 R{sub g} as predicted by the advection-dominated accretion flow paradigm. The measurements depend strongly on the assumed emission geometry, with most results providing no clear picture of radius evolution. If the inclination is constrained to roughly 20 Degree-Sign , however, the measurements based on the thermal disk emission suggest a mildly receding disk at a luminosity of 0.4% L{sub Edd}. The iron abundance varies between {approx}1 and 2 solar abundances, with the i = 20 Degree-Sign results indicating a negative correlation with luminosity, though this is likely due to a change in disk illumination geometry.

  10. The Causal Connection Between Disc and Power-Law Variability in Hard State Black Hole X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Uttley, P.; Wilkinson, T.; Cassatella, P.; Wilms, J.; Pottschimdt, K.; Hanke, M.; Boeck, M.

    2010-01-01

    We use the XMM-Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. \\Ve show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time-delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few ms, consistent with the disc variations being dominated by X-ray heating by the power-law, with the short lag corresponding to the light-travel time between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.

  11. A dichotomy between the hard state spectral properties of black hole and neutron star X-ray binaries

    NASA Astrophysics Data System (ADS)

    Burke, M. J.; Gilfanov, M.; Sunyaev, R.

    2017-04-01

    We analyse the spectra of black hole (BH) and neutron star (NS) X-ray binaries (XBs) in the hard state using archival RXTE observations. We find that there is a clear dichotomy in the strength of Comptonization between NS and BH sources, as measured by both the Compton y-parameter and the amplification factor A, with distinct groups of BH and NS XBs separated at y ∼ 0.9 and A ∼ 3. The electron temperature kTe can occupy a broad range in BH systems, from kTe ∼ 30 to 200 keV, whereas for NSs kTe is peaked at ∼15-25 keV, but can extend to higher values. The difference between BHs and NSs in y implies that kTe is higher at a given optical depth for BH XBs. Our results also imply that for NS systems the accreting material loses ∼1/2-2/3 of its energy through Comptonization in the corona. The remaining energy is released on the surface of the NS, making it a powerful source of soft radiation, which alters the properties of the Comptonizing corona. Finally, we find evidence at the ∼2.4σ confidence level that Comptonization parameters may be correlated with the NS spin, whereas no correlation with the BH spin is found. Our results highlight a further observational distinction between BH and NS XBs, which is a consequence of NSs possessing a physical surface.

  12. The Causal Connection Between Disc and Power-Law Variability in Hard State Black Hole X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Uttley, P.; Wilkinson, T.; Cassatella, P.; Wilms, J.; Pottschimdt, K.; Hanke, M.; Boeck, M.

    2010-01-01

    We use the XMM-Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. \\Ve show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time-delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few ms, consistent with the disc variations being dominated by X-ray heating by the power-law, with the short lag corresponding to the light-travel time between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.

  13. Infrared absorber based on sandwiched two-dimensional black phosphorus metamaterials.

    PubMed

    Wang, Jiao; Jiang, Yannan

    2017-03-06

    As a direct band gap two-dimensional (2D) semiconductor material, black phosphorus (BP) bridges the characteristics of graphene, with a zero or near-zero band gap, and transition metal dichalcogenides, with a wide band gap. In the infrared (IR) regime, 2D BP materials can harvest electromagnetic energy due to losses derived from its surface conductivity. In this paper, we propose an IR absorber design comprising 2D BP metamaterials sandwiched between dielectric layers. The multilayered sandwich-like absorber structure is mounted on a full reflective gold mirror, which forms a Fabry-Perot resonator to strengthen light-matter interactions. Harvested surface plasmons are excited around the 2D BP metamaterial edges, and the incident IR light can be efficiently dissipated by increasing the number of layers of the sandwich-like structure (NLSS). The physical absorption mechanism can be attributed to the destructive interference from the metamaterials, which can be enhanced with increasing NLSS. Here, a phase difference of about 180° is obtained between the directly reflected wave from the first interface and the emergent wave derived from the superposition of the multiple reflections among the resonator, and the amplitude of the emergent wave is steadily reduced to a value close to that of the directly reflected wave with increasing NLSS for incident transverse-magnetic polarized IR illumination.

  14. Air-stable few-layer black phosphorus phototransistor for near-infrared detection

    NASA Astrophysics Data System (ADS)

    Na, Junhong; Park, Kichul; Kim, Jin Tae; Choi, Won Kook; Song, Yong-Won

    2017-02-01

    We have demonstrated a few-layer black phosphorus (BP) phototransistor of stable operation in ambient air environment and at near-infrared light (λ = 1550 nm). The air-stable electronic and optoelectronic properties of the few-layer BP phototransistor have been achieved by a proper Al2O3 passivation. The optical identification method and qualitative and quantitative electrical characterizations of the few-layer BP phototransistor in dark state confirmed that the device performance was robust in ambient air, to further chemical treatments, and storage of more than six months. In addition, the low-frequency noise characterizations had revealed that the noise spectral density related to the sensitivity of phototransistor was reduced. Owing to the suppression of interaction between few-layer BP and adsorbates arising from the Al2O3 passivation, a fast rise time of the few-layer BP phototransistor, less than 100 μs, had been observed, demonstrating the intrinsic photoresponse properties of few-layer BP. The low dark current of ˜4 nA at the operation bias and the reasonable responsivity of ˜6 mA W-1 were obtained under the condition lacking adsorbates interactions. Internally, the dark current and responsivity level was tunable by changing the operation bias. Our results are close to the intrinsic properties of the few-layer BP phototransistor, implying that it can be a building block of functioned few-layer BP photodetectors.

  15. Mid-Infrared Selected Quasars I: Virial Black Hole Mass and Eddington Ratios

    NASA Astrophysics Data System (ADS)

    Dai, Yu Sophia; Elvis, Martin; Bergeron, Jacqueline; Fazio, Giovanni G.; Huang, Jiasheng; Wilkes, Belinda J.; Willmar, Christopher

    2014-06-01

    We provide a catalog of 391 mid-infrared-selected (MIR, 24μm) broad-emission-line (BEL, type 1) quasars in the 20 square deg SWIRE Lockman Hole field. This quasar sample is selected in the MIR from Spitzer MIPS with S24 >0.4mJy, and jointly with an optical magnitude limit of r (AB)= 22.5. The catalog is based on MMT spectroscopy to select BEL quasars, and extends the SDSS coverage to fainter magnitudes and a more complete quasar population. The MIR-selected quasar sample peaks at z ˜1.4, and shows a significant and constant (20%) fraction of objects with extended SDSS photometry, previously missed by the SDSS optical point source dominant color selection. This sample also recovers a significant population of z < 3 quasars at i > 19.1, previously dropped by SDSS for efficiency consideration. We also investigate the continuum luminosity and line profile of these MIR quasars, estimate their virial black hole masses, and provide the Eddington ratios. The SMBH mass shows evidence of downsizing, though the Eddington ratios remain constant at 1 < z < 4. Compared to point sources in the same redshift range, extended sources at z < 1 show systematically lower Eddington ratios. The catalog and spectra will be publicly available online.

  16. Air-stable few-layer black phosphorus phototransistor for near-infrared detection.

    PubMed

    Na, Junhong; Park, Kichul; Kim, Jin Tae; Choi, Won Kook; Song, Yong-Won

    2017-02-24

    We have demonstrated a few-layer black phosphorus (BP) phototransistor of stable operation in ambient air environment and at near-infrared light (λ = 1550 nm). The air-stable electronic and optoelectronic properties of the few-layer BP phototransistor have been achieved by a proper Al2O3 passivation. The optical identification method and qualitative and quantitative electrical characterizations of the few-layer BP phototransistor in dark state confirmed that the device performance was robust in ambient air, to further chemical treatments, and storage of more than six months. In addition, the low-frequency noise characterizations had revealed that the noise spectral density related to the sensitivity of phototransistor was reduced. Owing to the suppression of interaction between few-layer BP and adsorbates arising from the Al2O3 passivation, a fast rise time of the few-layer BP phototransistor, less than 100 μs, had been observed, demonstrating the intrinsic photoresponse properties of few-layer BP. The low dark current of ∼4 nA at the operation bias and the reasonable responsivity of ∼6 mA W(-1) were obtained under the condition lacking adsorbates interactions. Internally, the dark current and responsivity level was tunable by changing the operation bias. Our results are close to the intrinsic properties of the few-layer BP phototransistor, implying that it can be a building block of functioned few-layer BP photodetectors.

  17. The Accreting Black Hole Swift J1753.5-0127 from Radio to Hard X-Ray

    NASA Astrophysics Data System (ADS)

    Tomsick, John A.; Rahoui, Farid; Kolehmainen, Mari; Miller-Jones, James; Fürst, Felix; Yamaoka, Kazutaka; Akitaya, Hiroshi; Corbel, Stéphane; Coriat, Mickael; Done, Chris; Gandhi, Poshak; Harrison, Fiona A.; Huang, Kuiyun; Kaaret, Philip; Kalemci, Emrah; Kanda, Yuka; Migliari, Simone; Miller, Jon M.; Moritani, Yuki; Stern, Daniel; Uemura, Makoto; Urata, Yuji

    2015-07-01

    We report on multiwavelength measurements of the accreting black hole Swift J1753.5-0127 in the hard state at low luminosity (L ˜ 2.7 × 1036 erg s-1 assuming a distance of d = 3 kpc) in 2014 April. The radio emission is optically thick synchrotron, presumably from a compact jet. We take advantage of the low extinction (E(B-V)=0.45 from earlier work) and model the near-IR to UV emission with a multitemperature disk model. Assuming a black hole mass of MBH = 5 M⊙ and a system inclination of i = 40°, the fits imply an inner radius for the disk of Rin/Rg > 212d3(MBH/5 M⊙)-1, where Rg is the gravitational radius of the black hole and d3 is the distance to the source in units of 3 kpc. The outer radius is Rout/Rg=90,000 d3(MBH/5 M⊙)-1, which corresponds to 6.6 × 1010 d3 cm, consistent with the expected size of the disk given previous measurements of the size of the companion's Roche lobe. The 0.5-240 keV energy spectrum measured by Swift/X-ray Telescope (XRT), Suzaku (XIS, PIN, and GSO), and Nuclear Spectroscopic Telescope Array is relatively well characterized by an absorbed power law with a photon index of Γ = 1.722 ± 0.003 (90% confidence error), but a significant improvement is seen when a second continuum component is added. Reflection is a possibility, but no iron line is detected, implying a low iron abundance. We are able to fit the entire (radio to 240 keV) spectral energy distribution (SED) with a multitemperature disk component, a Comptonization component, and a broken power law, representing the emission from the compact jet. The broken power law cannot significantly contribute to the soft X-ray emission, and this may be related to why Swift J1753.5-0127 is an outlier in the radio/X-ray correlation. The broken power law (i.e., the jet) might dominate above 20 keV, which would constrain the break frequency to be between 2.4 × 1010 and 3.6 × 1012 Hz. Although the fits to the full SED do not include significant thermal emission in the X-ray band

  18. Lighthouse in the dust: infrared echoes of periodic emission from massive black hole binaries★

    NASA Astrophysics Data System (ADS)

    D'Orazio, Daniel J.; Haiman, Zoltán

    2017-09-01

    The optical and UV emission from sub-parsec massive black hole binaries (MBHBs) in active galactic nuclei (AGNs) is believed to vary periodically, on time-scales comparable to the binary's orbital time. If driven by accretion rate fluctuations, the variability could be isotropic. If dominated by relativistic Doppler modulation, the variability should instead be anisotropic, resembling a rotating forward-beamed lighthouse. We consider the infrared (IR) reverberation of either type of periodic emission by pc-scale circumbinary dust tori. We predict the phase and amplitude of IR variability as a function of the ratio of dust light crossing time to the source variability period, and of the torus inclination and opening angle. We enumerate several differences between the isotropic and anisotropic cases. Interestingly, for a nearly face-on binary with an inclined dust torus, the Doppler boost can produce IR variability without any observable optical/UV variability. Such orphan-IR variability would have been missed in optical searches for periodic AGNs. We apply our models to time-domain WISE IR data from the MBHB candidate PG 1302-102 and find consistency with dust reverberation by both isotropically emitting and Doppler-boosted sources in the shorter wavelength W1-W2 (2.8 → 5.3 μm) bands. We constrain the dust torus to be thin (aspect ratio ∼ 0.1), with an inner radius at 1-5 pc. More generally, our dust-echo models will aid in identifying new MBHB candidates, determining their nature and constraining the physical properties of MBHBs and their dust tori.

  19. LOCAL LUMINOUS INFRARED GALAXIES. III. CO-EVOLUTION OF BLACK HOLE GROWTH AND STAR FORMATION ACTIVITY?

    SciTech Connect

    Alonso-Herrero, Almudena; Hernan-Caballero, Antonio; Pereira-Santaella, Miguel; Rieke, George H.; Diamond-Stanic, Aleksandar M.; Wang Yiping; Rigopoulou, Dimitra

    2013-03-10

    Local luminous infrared (IR) galaxies (LIRGs) have both high star formation rates (SFR) and a high AGN (Seyfert and AGN/starburst composite) incidence. Therefore, they are ideal candidates to explore the co-evolution of black hole (BH) growth and star formation (SF) activity, not necessarily associated with major mergers. Here, we use Spitzer/IRS spectroscopy of a complete volume-limited sample of local LIRGs (distances of <78 Mpc). We estimate typical BH masses of 3 Multiplication-Sign 10{sup 7} M{sub Sun} using [Ne III] 15.56 {mu}m and optical [O III] {lambda}5007 gas velocity dispersions and literature stellar velocity dispersions. We find that in a large fraction of local LIRGs, the current SFR is taking place not only in the inner nuclear {approx}1.5 kpc region, as estimated from the nuclear 11.3 {mu}m PAH luminosities, but also in the host galaxy. We next use the ratios between the SFRs and BH accretion rates (BHAR) to study whether the SF activity and BH growth are contemporaneous in local LIRGs. On average, local LIRGs have SFR to BHAR ratios higher than those of optically selected Seyferts of similar active galactic nucleus (AGN) luminosities. However, the majority of the IR-bright galaxies in the revised-Shapley-Ames Seyfert sample behave like local LIRGs. Moreover, the AGN incidence tends to be higher in local LIRGs with the lowest SFRs. All of this suggests that in local LIRGs there is a distinct IR-bright star-forming phase taking place prior to the bulk of the current BH growth (i.e., AGN phase). The latter is reflected first as a composite and then as a Seyfert, and later as a non-LIRG optically identified Seyfert nucleus with moderate SF in its host galaxy.

  20. Supermassive black holes and their host galaxies. II. The correlation with near-infrared luminosity revisited

    SciTech Connect

    Läsker, Ronald; Van de Ven, Glenn; Ferrarese, Laura; Shankar, Francesco

    2014-01-01

    We present an investigation of the scaling relations between supermassive black hole (SMBH) masses, M {sub •}, and their host galaxies' K-band bulge (L {sub bul}) and total (L {sub tot}) luminosities. The wide-field WIRCam imager at the Canada-France-Hawaii-Telescope was used to obtain the deepest and highest resolution near-infrared images available for a sample of 35 galaxies with securely measured M {sub •}, selected irrespective of Hubble type. For each galaxy, we derive bulge and total magnitudes using a two-dimensional image decomposition code that allows us to account, if necessary, for large- and small-scale disks, cores, bars, nuclei, rings, envelopes, and spiral arms. We find that the present-day M {sub •}-L {sub bul} and M {sub •}-L {sub tot} relations have consistent intrinsic scatter, suggesting that M {sub •} correlates equally well with bulge and total luminosity of the host. Our analysis provides only mild evidence of a decreased scatter if the fit is restricted to elliptical galaxies. The log-slopes of the M {sub •}-L {sub bul} and M {sub •}-L {sub tot} relations are 0.75 ± 0.10 and 0.92 ± 0.14, respectively. However, while the slope of the M {sub •}-L {sub bul} relation depends on the detail of the image decomposition, the characterization of M {sub •}-L {sub tot} does not. Given the difficulties and ambiguities of decomposing galaxy images into separate components, our results indicate that L {sub tot} is more suitable as a tracer of SMBH mass than L {sub bul}, and that the M {sub •}-L {sub tot} relation should be used when studying the co-evolution of SMBHs and galaxies.

  1. Supermassive black holes and their host galaxies. I. Bulge luminosities from dedicated near-infrared data

    SciTech Connect

    Läsker, Ronald; Van de Ven, Glenn; Ferrarese, Laura

    2014-01-01

    In an effort to secure, refine, and supplement the relation between central supermassive black hole masses, M {sub •}, and the bulge luminosities of their host galaxies, L {sub bul}, we obtained deep, high spatial resolution K-band images of 35 nearby galaxies with securely measured M {sub •}, using the wide-field WIRCam imager at the Canada-France-Hawaii-Telescope. A dedicated data reduction and sky subtraction strategy was adopted to estimate the brightness and structure of the sky, a critical step when tracing the light distribution of extended objects in the near-infrared. From the final image product, bulge and total magnitudes were extracted via two-dimensional profile fitting. As a first order approximation, all galaxies were modeled using a simple Sérsic-bulge+exponential-disk decomposition. However, we found that such models did not adequately describe the structure that we observed in a large fraction of our sample galaxies which often include cores, bars, nuclei, inner disks, spiral arms, rings, and envelopes. In such cases, we adopted profile modifications and/or more complex models with additional components. The derived bulge magnitudes are very sensitive to the details and number of components used in the models, although total magnitudes remain almost unaffected. Usually, but not always, the luminosities and sizes of the bulges are overestimated when a simple bulge+disk decomposition is adopted in lieu of a more complex model. Furthermore, we found that some spheroids are not well fit when the ellipticity of the Sérsic model is held fixed. This paper presents the details of the image processing and analysis, while we discuss how model-induced biases and systematics in bulge magnitudes impact the M {sub •}-L {sub bul} relation in a companion paper.

  2. The Nature of Hard X-Ray (3–24 keV) Detected Luminous Infrared Galaxies in the COSMOS Field

    NASA Astrophysics Data System (ADS)

    Matsuoka, Kenta; Ueda, Yoshihiro

    2017-04-01

    We investigate the nature of far-infrared (70 μm) and hard X-ray (3–24 keV) selected galaxies in the COSMOS field detected with both Spitzer and the Nuclear Spectroscopic Telescope Array (NuSTAR). By matching the Spitzer-COSMOS catalog with the NuSTAR-COSMOS catalog, we obtain a sample consisting of a hyperluminous infrared galaxy with {log}({L}{IR}/{L}ȯ )≥slant 13, 12 ultraluminous infrared galaxies with 12≤slant {log} ({L}{IR}/{L}ȯ )≤slant 13, and 10 luminous infrared galaxies with 11≤slant {log} ({L}{IR}/{L}ȯ )≤slant 12, i.e., 23 Hy/U/LIRGs in total. Using their X-ray hardness ratios, we find that 12 sources are obscured active galactic nuclei (AGNs) with absorption column densities of {N}{{H}}> {10}22 cm‑2, including several Compton-thick ({N}{{H}}∼ {10}24 cm‑2) AGN candidates. On the basis of the infrared (60 μm) and intrinsic X-ray luminosities, we examine the relation between star formation (SF) and AGN luminosities of the 23 Hy/U/LIRGs. We find that the correlation is similar to that of the optically selected AGNs reported by Netzer, whereas local, far-infrared selected U/LIRGs show higher SF-to-AGN luminosity ratios than the average of our sample. This result suggests that our Hy/U/LIRGs detected both with Spitzer and NuSTAR are likely situated in a transition epoch between AGN-rising and cold-gas diminishing phases in SF-AGN evolutional sequences. The nature of a Compton-thick AGN candidate newly detected above 8 keV with NuSTAR (ID 245 in Civano et al.) is briefly discussed.

  3. Black hole accretion disks - Electrodynamic coupling of accretion-disk coronae and the partitioning of soft and hard X-ray emission

    NASA Technical Reports Server (NTRS)

    Kuperus, M.; Ionson, J. A.

    1985-01-01

    It is demonstrated that the observed large ratio of hard to soft X-ray emission and the bimodel behavior of black hole accreting X-ray sources such as Cygnus X-1 can be described in terms of a magnetically structured accretion disk corona which is electrodynamically coupled to the disk turbulent motions while the disk is thermodynamically coupled to the corona as described by a feedback parameter delta. The observed ratio of hard to soft X-ray emission is independent of the disk thickness, and weakly dependent of the disk parameter alpha relating the disk viscous stresses to the total pressure. Observed values of the luminosity ratio point towards strong differences of the feedback of the low state compared to the high state, in the sense that low state means small feedback (delta less than 0.2) and high state means strong feedback delta of about 0.5.

  4. Black hole accretion disks - Electrodynamic coupling of accretion-disk coronae and the partitioning of soft and hard X-ray emission

    NASA Technical Reports Server (NTRS)

    Kuperus, M.; Ionson, J. A.

    1985-01-01

    It is demonstrated that the observed large ratio of hard to soft X-ray emission and the bimodel behavior of black hole accreting X-ray sources such as Cygnus X-1 can be described in terms of a magnetically structured accretion disk corona which is electrodynamically coupled to the disk turbulent motions while the disk is thermodynamically coupled to the corona as described by a feedback parameter delta. The observed ratio of hard to soft X-ray emission is independent of the disk thickness, and weakly dependent of the disk parameter alpha relating the disk viscous stresses to the total pressure. Observed values of the luminosity ratio point towards strong differences of the feedback of the low state compared to the high state, in the sense that low state means small feedback (delta less than 0.2) and high state means strong feedback delta of about 0.5.

  5. Kinetic analysis of reactions of Si-based epoxy resins by near-infrared spectroscopy, 13C NMR and soft-hard modelling.

    PubMed

    Garrido, Mariano; Larrechi, Maria Soledad; Rius, F Xavier; Mercado, Luis Adolfo; Galià, Marina

    2007-02-05

    Soft- and hard-modelling strategy was applied to near-infrared spectroscopy data obtained from monitoring the reaction between glycidyloxydimethylphenyl silane, a silicon-based epoxy monomer, and aniline. On the basis of the pure soft-modelling approach and previous chemical knowledge, a kinetic model for the reaction was proposed. Then, multivariate curve resolution-alternating least squares optimization was carried out under a hard constraint, that compels the concentration profiles to fulfil the proposed kinetic model at each iteration of the optimization process. In this way, the concentration profiles of each species and the corresponding kinetic rate constants of the reaction, unpublished until now, were obtained. The results obtained were contrasted with 13C NMR. The joint interval test of slope and intercept for detecting bias was not significant (alpha=5%).

  6. Deposition and characterization of far-infrared absorbing gold black films

    NASA Technical Reports Server (NTRS)

    Advena, Donna J.; Bly, Vincent T.; Cox, J. T.

    1993-01-01

    A process is described for producing gold black films with high absorptance in the far IR. The optical and electrical properties of these films have been studied with particular emphasis on the absorptance of films at wavelengths as long as 50 microns. A substantial decrease in absorptance near 50 microns has been observed for pure gold black films on aging in air. This degradation can be largely avoided by alloying the gold with a small percentage of copper during the deposition. Preliminary results on two methods for delineating gold black films are also presented.

  7. Deposition and characterization of far-infrared absorbing gold black films

    NASA Technical Reports Server (NTRS)

    Advena, Donna J.; Bly, Vincent T.; Cox, J. T.

    1993-01-01

    A process is described for producing gold black films with high absorptance in the far IR. The optical and electrical properties of these films have been studied with particular emphasis on the absorptance of films at wavelengths as long as 50 microns. A substantial decrease in absorptance near 50 microns has been observed for pure gold black films on aging in air. This degradation can be largely avoided by alloying the gold with a small percentage of copper during the deposition. Preliminary results on two methods for delineating gold black films are also presented.

  8. Near-infrared observations of the black hole transient GRS 1716-249.

    NASA Astrophysics Data System (ADS)

    Joshi, Vishal; Vadwale, Santosh; Ganesh, Shashikiran

    2017-03-01

    We report near-infrared photometric observations of GRS 1716-249 during the on-going outburst (ATel #9876, #9895, #10036, #10069). Observations were carried out on UT 20.99 March 2017 with the Mount Abu 1.2 meter telescope (+ PRL Near-Infrared Imager/Spectrograph).

  9. Broadband X-Ray Spectra of GX 339-4 and the Geometry of Accreting Black Holes in the Hard State

    NASA Technical Reports Server (NTRS)

    Tomsick, John A.; Kalemci, Emrah; Kaaret, Philip; Markoff, Sera; Corbel, Stephane; Migliari, Simone; Fender, Rob; Bailyn, Charles D.; Buxton, Michelle M.

    2008-01-01

    A major question in the study of black hole binaries involves our understanding of the accretion geometry when the sources are in the "hard" state, with an X-ray energy spectrum dominated by a hard power-law component and radio emission coming from a steady "compact" jet. Although the common hard state picture is that the accretion disk is truncated, perhaps at hundreds of gravitational radii (Rg) from the black hole, recent results for the recurrent transient GX 339-4 by Miller and coworkers show evidence for disk material very close to the black hole's innermost stable circular orbit. That work studied GX 339-4 at a luminosity of approximately 5% of the Eddington limit (L(sub Edd) and used parameters from a relativistic reflection model and the presence of a thermal component as diagnostics. Here we use similar diagnostics but extend the study to lower luminosities (2.3% and 0.8% L(sub Edd)) using Swift and RXTE observations of GX 339-4. We detect a thermal component with an inner disk temperature of approximately 0.2 keV at 2.3% L (sub Edd). At both luminosities, we detect broad features due to iron K-alpha that are likely related to reflection of hard X-rays off disk material. If these features are broadened by relativistic effects, they indicate that the material resides within 10 Rg, and the measurements are consistent with the disk's inner radius remaining at approximately 4 Rg down to 0.8% L(sub Edd). However, we also discuss an alternative model for the broadening, and we note that the evolution of the thermal component is not entirely consistent with the constant inner radius interpretation. Finally, we discuss the results in terms of recent theoretical work by Liu and co-workers on the possibility that material may condense out of an Advection-Dominated Accretion Flow to maintain an inner optically thick disk.

  10. Broadband X-Ray Spectra of GX 339-4 and the Geometry of Accreting Black Holes in the Hard State

    NASA Technical Reports Server (NTRS)

    Tomsick; Kalemci; Kaaret; Markoff; Corbel; Migliari; Fender; Bailyn; Buxton

    2008-01-01

    A major question in the study of black hole binaries involves our understanding of the accretion geometry when the sources are in the "hard" state. In this state, the X-ray energy spectrum is dominated by a hard power-law component and radio observations indicate the presence of a steady and powerful "compact" jet. Although the common hard state picture is that the accretion disk is truncated, perhaps at hundreds of gravitational radii (R(sub g)) from the black hole, recent results for the recurrent transient GX 339-4 by Miller and co-workers show evidence for optically thick material very close to the black hole's innermost stable circular orbit. That work focused on an observation of GX 339-4 at a luminosity of about 5% of the Eddington limit (L(sub Edd)) and used parameters from a relativistic reflection model and the presence of a soft, thermal component as diagnostics. In this work, we use similar diagnostics, but extend the study to lower luminosities (2.3% and 0.8% L(sub Edd)) using Swift and RXTE observations of GX 339-4. We detect a thermal component with an inner disk temperature of approx.0.2 keV at 2.3% L(sub Edd). At 0.8% L(sub Edd), the spectrum is consistent with the presence of such a component, but the component is not required with high confidence. At both luminosities, we detect broad features due to iron Ka that are likely related to reflection of hard X-rays off the optically thick material. If these features are broadened by relativistic effects, they indicate that optically thick material resides within 10 R(sub g) down to 0.8% L(sub Edd), and the measurements are consistent with the inner radius of the disk remaining at approx.4 R(sub g) down to this level. However, we also discuss an alternative model for the broadening, and we note that the evolution of the thermal component is not entirely consistent with the constant inner radius interpretation. Finally, we discuss the results in terms of recent theoretical work by Liu and co-workers on

  11. Broadband X-Ray Spectra of GX 339-4 and the Geometry of Accreting Black Holes in the Hard State

    NASA Technical Reports Server (NTRS)

    Tomsick; Kalemci; Kaaret; Markoff; Corbel; Migliari; Fender; Bailyn; Buxton

    2008-01-01

    A major question in the study of black hole binaries involves our understanding of the accretion geometry when the sources are in the "hard" state. In this state, the X-ray energy spectrum is dominated by a hard power-law component and radio observations indicate the presence of a steady and powerful "compact" jet. Although the common hard state picture is that the accretion disk is truncated, perhaps at hundreds of gravitational radii (R(sub g)) from the black hole, recent results for the recurrent transient GX 339-4 by Miller and co-workers show evidence for optically thick material very close to the black hole's innermost stable circular orbit. That work focused on an observation of GX 339-4 at a luminosity of about 5% of the Eddington limit (L(sub Edd)) and used parameters from a relativistic reflection model and the presence of a soft, thermal component as diagnostics. In this work, we use similar diagnostics, but extend the study to lower luminosities (2.3% and 0.8% L(sub Edd)) using Swift and RXTE observations of GX 339-4. We detect a thermal component with an inner disk temperature of approx.0.2 keV at 2.3% L(sub Edd). At 0.8% L(sub Edd), the spectrum is consistent with the presence of such a component, but the component is not required with high confidence. At both luminosities, we detect broad features due to iron Ka that are likely related to reflection of hard X-rays off the optically thick material. If these features are broadened by relativistic effects, they indicate that optically thick material resides within 10 R(sub g) down to 0.8% L(sub Edd), and the measurements are consistent with the inner radius of the disk remaining at approx.4 R(sub g) down to this level. However, we also discuss an alternative model for the broadening, and we note that the evolution of the thermal component is not entirely consistent with the constant inner radius interpretation. Finally, we discuss the results in terms of recent theoretical work by Liu and co-workers on

  12. Broadband X-Ray Spectra of GX 339-4 and the Geometry of Accreting Black Holes in the Hard State

    NASA Technical Reports Server (NTRS)

    Tomsick, John A.; Kalemci, Emrah; Kaaret, Philip; Markoff, Sera; Corbel, Stephane; Migliari, Simone; Fender, Rob; Bailyn, Charles D.; Buxton, Michelle M.

    2008-01-01

    A major question in the study of black hole binaries involves our understanding of the accretion geometry when the sources are in the "hard" state, with an X-ray energy spectrum dominated by a hard power-law component and radio emission coming from a steady "compact" jet. Although the common hard state picture is that the accretion disk is truncated, perhaps at hundreds of gravitational radii (Rg) from the black hole, recent results for the recurrent transient GX 339-4 by Miller and coworkers show evidence for disk material very close to the black hole's innermost stable circular orbit. That work studied GX 339-4 at a luminosity of approximately 5% of the Eddington limit (L(sub Edd) and used parameters from a relativistic reflection model and the presence of a thermal component as diagnostics. Here we use similar diagnostics but extend the study to lower luminosities (2.3% and 0.8% L(sub Edd)) using Swift and RXTE observations of GX 339-4. We detect a thermal component with an inner disk temperature of approximately 0.2 keV at 2.3% L (sub Edd). At both luminosities, we detect broad features due to iron K-alpha that are likely related to reflection of hard X-rays off disk material. If these features are broadened by relativistic effects, they indicate that the material resides within 10 Rg, and the measurements are consistent with the disk's inner radius remaining at approximately 4 Rg down to 0.8% L(sub Edd). However, we also discuss an alternative model for the broadening, and we note that the evolution of the thermal component is not entirely consistent with the constant inner radius interpretation. Finally, we discuss the results in terms of recent theoretical work by Liu and co-workers on the possibility that material may condense out of an Advection-Dominated Accretion Flow to maintain an inner optically thick disk.

  13. Infrared heterodyne spectroscopy of astronomical and laboratory sources at 8.5 micron. [absorption line profiles of nitrogen oxide and black body emission from Moon and Mars

    NASA Technical Reports Server (NTRS)

    Mumma, M.; Kostiuk, T.; Cohen, S.; Buhl, D.; Vonthuna, P. C.

    1974-01-01

    The first infrared heterodyne spectrometer using tuneable semiconductor (PbSe) diode lasers has been constructed and was used near 8.5 micron to measure absorption line profiles of N2O in the laboratory and black body emission from the Moon and from Mars. Spectral information was recorded over a 200 MHz bandwidth using an 8-channel filter bank. The resolution was 25 MHz and the minimum detectable (black body) power was 1 x 10 to the minus 16th power watts for 8 minutes of integration. The results demonstrate the usefulness of heterodyne spectroscopy for the study of remote and local sources in the infrared.

  14. Increased intramuscular fat improves both 'chewiness' and 'hardness' as defined in ISO5492:1992 of beef Longissimus muscle of Holstein × Japanese black F1 steers.

    PubMed

    Sasaki, Keisuke; Motoyama, Michiyo; Narita, Takumi

    2012-04-01

    It is considered that high-fat beef is more 'tender' than low-fat beef in Japanese consumers. However, 'tenderness' which has been an important beef characteristic, has not been commonly defined. ISO5492:1992 provides internationally established items for sensory texture analysis with simple definitions, and the items classified under 'chewiness' and 'hardness' as defined in the international standard are characterized as useful texture descriptors for beef. The aim of this study was to investigate the effects of intramuscular fat on beef texture using the ISO5492 texture vocabulary. Longissimus muscles were harvested from Holstein × Japanese black F1 beef steers with different intramuscular fat levels and were subjected to sensory tests by a trained panel using ISO5492:1992 texture terms. Correspondence analysis indicated that the intramuscular fat level was related to both 'chewiness' and 'hardness' and the intensities of these characteristics decreased as intramuscular fat increased. These findings suggest that intramuscular fat improves both 'chewiness' and 'hardness' as defined in ISO5492:1992. © 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

  15. "Man, This Is Hard": A Case Study of How Race and Religion Affect Cross-Racial Interaction for Black Students

    ERIC Educational Resources Information Center

    Park, Julie J.

    2012-01-01

    This study examines how multiple facets of students' identities affect their experiences with cross-racial interaction. I consider how the intersection between two identity categories--race and religion--affected six Black students' experiences with cross-racial interaction in a multiracial religious student organization. While the pursuit of…

  16. Swift/BAT hard X-ray monitoring: A New Outburst of Black Hole Transient H1743-322

    NASA Astrophysics Data System (ADS)

    Lin, Jie; Yu, Wenfei; Yan, Zhen; Zhang, Hui; Zhang, Wenda

    2016-02-01

    H 1743-322 is one of the a few black hole transients which undergo frequent outbursts in the past decade. From December 2009 to June 2015, it has turned into outbursts for at least eight times (ATEL #2364, #2774, #3277, #3842, #4418, #5241, #6474, and #7607), and its outbursts take place rather regularly with recurrence time of about 7-8 months.

  17. A new deep, hard X-ray survey of M31: Identifying Black Holes and Neutron Stars in the X-ray Binary Population of our Nearest Neighbor

    NASA Astrophysics Data System (ADS)

    Wik, Daniel R.; Hornschemeier, Ann E.; Yukita, Mihoko; Ptak, Andrew; Lehmer, Bret; Maccarone, Thomas J.; Antoniou, Vallia; Zezas, Andreas; Harrison, Fiona; Stern, Daniel; Venters, Tonia M.; Williams, Benjamin F.; Eracleous, Michael; Plucinsky, Paul P.; Pooley, David A.

    2016-04-01

    X-ray binaries (XRBs) trace old and new stellar populations in galaxies, and thus star formation history and star formation rate. X-ray emission from XRBs may be responsible for significant amounts of heating of the early Intergalactic Medium (IGM) at Cosmic Dawn and may also play a significant role in reionization. Until recently, the hard emission from these populations could only be studied for XRBs in our own galaxy, where it is often difficult to measure accurate distances and thus luminosities. The launch of NuSTAR, the first focusing hard X-ray observatory, has allowed us to resolve the brightest XRBs (down to LX ~ few times 10^38 erg/s) in galaxies like NGC 253, M83, and M82 up to 4 Mpc away. To reach much lower X-ray luminosities that are more typical of XRBs in the Milky Way (Lx <~ 10^37 erg/s), we have observed M31 in 4 NuSTAR fields for more than 1 Ms total exposure, covering younger stellar population in a swath of the disk (within the footprint of the Panchromatic Hubble Andromeda Treasury (PHAT) Survey) and the older populations of the bulge. We detect 120 sources in the 4-25 keV band and over 40 hard band (12-25 keV) accreting black holes and neutron stars, distinguished by their spectral shape in this band. The luminosity function (LF) of the hard band detected sources are compared to Swift/BAT-derived LFs of the Milky Way population, which reveals an excess of luminous sources in M31 when correcting for star formation rate and stellar mass. We also discuss implications for this updated understanding of XRB populations on early-Universe measurements in, e.g., the 7 Ms Chandra Deep Field survey.

  18. The black hole mass of NGC 4151. II. Stellar dynamical measurement from near-infrared integral field spectroscopy

    SciTech Connect

    Onken, Christopher A.; Ferrarese, Laura; Valluri, Monica; Brown, Jonathan S.; McGregor, Peter J.; Peterson, Bradley M.; Pogge, Richard W.; Bentz, Misty C.; Vestergaard, Marianne; Storchi-Bergmann, Thaisa; Riffel, Rogemar A. E-mail: mvalluri@umich.edu

    2014-08-10

    We present a revised measurement of the mass of the central black hole (M{sub BH} ) in the Seyfert 1 galaxy NGC 4151. The new stellar dynamical mass measurement is derived by applying an axisymmetric orbit-superposition code to near-infrared integral field data obtained using adaptive optics with the Gemini Near-infrared Integral Field Spectrograph (NIFS). When our models attempt to fit both the NIFS kinematics and additional low spatial resolution kinematics, our results depend sensitively on how χ{sup 2} is computed—probably a consequence of complex bar kinematics that manifest immediately outside the nuclear region. The most robust results are obtained when only the high spatial resolution kinematic constraints in the nuclear region are included in the fit. Our best estimates for the black hole mass and H-band mass-to-light ratio are M{sub BH} ∼ 3.76 ± 1.15 × 10{sup 7} M{sub ☉} (1σ error) and Y{sub H} ∼ 0.34 ± 0.03 M{sub ☉}/L{sub ☉} (3σ error), respectively (the quoted errors reflect the model uncertainties). Our black hole mass measurement is consistent with estimates from both reverberation mapping (3.57{sub −0.37}{sup +0.45}×10{sup 7} M{sub ⊙}) and gas kinematics (3.0{sub −2.2}{sup +0.75}×10{sup 7} M{sub ⊙}; 1σ errors), and our best-fit mass-to-light ratio is consistent with the photometric estimate of Y{sub H} = 0.4 ± 0.2 M{sub ☉}/L{sub ☉}. The NIFS kinematics give a central bulge velocity dispersion σ{sub c} = 116 ± 3 km s{sup –1}, bringing this object slightly closer to the M{sub BH}-σ relation for quiescent galaxies. Although NGC 4151 is one of only a few Seyfert 1 galaxies in which it is possible to obtain a direct dynamical black hole mass measurement—and thus, an independent calibration of the reverberation mapping mass scale—the complex bar kinematics makes it less than ideally suited for this purpose.

  19. Technical note: determination of corn hardness in diverse corn germplasm using near-infrared reflectance baseline shift as a measure of grinding resistance.

    PubMed

    Hoffman, P C; Ngonyamo-Majee, D; Shaver, R D

    2010-04-01

    Vitreousness and Stenvert kernel hardness characteristics in corn germplasm have been related to in situ and in vivo starch digestibility in lactating dairy cows. Because of the tedious nature of determining vitreousness by manual dissection or conducting Stenvert hardness measurements, it is challenging to screen corn germplasm for animal performance potential. The resistance of corn to grinding is typically measured in a Stenvert mill and quantified by grinding time and column height. The baseline shift (BLS) of near-infrared reflectance spectroscopy, which is a normal artifact of grinding-induced particle size differentiation, was calculated and evaluated as an alternative measure of grinding resistance. Stenvert grind time, column height, BLS, and ruminal DM degradability (RDMD) of 31 diverse corn germplasm harvested in triplicate at 2 maturities were made. After grinding, total and 6 partial (100 nm) BLS were calculated [Sigma x(i)+x(j)..., where x(i)=log(10)(1/R) at the ith nanometer and R=reflectance] and compared with vitreousness, Stenvert grinding time, column height, or RDMD of corns using correlation and regression procedures. Total and all partial BLS were correlated with vitreousness, Stenvert measures, and RDMD. Relationships between BLS and vitreousness, Stenvert measures, or RDMD were stronger for partial BLS at shorter near-infrared wavelengths (1,080-1,180 nm) than at longer wavelengths (i.e., 2,280-2,380 nm) or total near-infrared BLS (1,000-2,498 nm). The partial BLS from 1,080 to 1,180 nm and vitreousness were better related to RDMD of corn germplasm than Stenvert grind time or column height.

  20. Thermogravimetric-Fourier transform infrared spectrometric analysis of CO2 gasification of reed (Phragmites australis) kraft black liquor.

    PubMed

    Yang, Qing; Yin, Xiuli; Wu, Chuangzhi; Wu, Shubin; Guo, Daliang

    2012-03-01

    CO(2) gasification of the reed (Phragmites australis) kraft black liquor (KBL) and its water-soluble lignin (WSL) was analyzed by thermogravimetry coupled with Fourier transform infrared spectrometry (TG-FTIR). In KBL gasification, major mass loss of KBL occurred between 150 and 1000°C, followed by a further slow mass loss until the heating was stopped and the TG curve leveled off. The TG profiles of the WSL and the KBL were similar during gasification; however, the differential thermogravimetry (DTG) curves and mass decrease from 300°C of the TG curves of the WSL and the KBL were different because of their dissimilar ingredients. The CO formation mechanism was the same and independent of structural types of lignins between reed and wood in their KBL CO(2) gasification.

  1. Structural analysis of lignin residue from black liquor and its thermal performance in thermogravimetric-Fourier transform infrared spectroscopy.

    PubMed

    Hu, Jun; Xiao, Rui; Shen, Dekui; Zhang, Huiyan

    2013-01-01

    Structural characteristics of benzene-ethanol-extracted lignin (BEL) and acetone-extracted lignin (AL) precipitated from black liquor were identified by elemental analysis, FTIR, (13)C NMR, and (1)H NMR, while the thermal behaviors were examined with thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR). The frequency of β-O-4 bonds per 100 C9 monomeric units was 28 and 17 for BEL and AL. Two-stage pyrolysis processes were observed for the two lignins. The mass loss rate of the initial solvent evolution stage (110-180 °C) of BEL was greater than that of AL. The two lignins presented slightly different mass loss curves and evolution profiles of gases in the main pyrolysis stage (280-500 °C). A global kinetic model was proposed for lignin pyrolysis and activation energies of 39.5 and 38.8 kJ/mol was obtained for BEL and AL. The results enhance understanding of lignin pyrolysis and facilitate commercial utilization of black-liquor lignin.

  2. Novel calibrations of virial black hole mass estimators in active galaxies based on X-ray luminosity and optical/near-infrared emission lines

    NASA Astrophysics Data System (ADS)

    Ricci, F.; La Franca, F.; Onori, F.; Bianchi, S.

    2017-02-01

    Context. It is currently only possible to accurately weigh, through reverberation mapping (RM), the masses of super massive black holes (BHs) in active galactic nuclei (AGN) for a small group of local and bright broad line AGN. Statistical demographic studies can be carried out considering the empirical scaling relation between the size of the broad line region (BLR) and the AGN optical continuum luminosity. There are still biases, however, against low-luminosity or reddened AGN, in which the rest-frame optical radiation can be severely absorbed or diluted by the host galaxy and the BLR emission lines can be hard to detect. Aims: Our purpose is to widen the applicability of virial-based single-epoch (SE) relations to measure reliably the BH masses for low-luminosity or intermediate and type 2 AGN, which the current methodology misses. We achieve this goal by calibrating virial relations based on unbiased quantities: the hard X-ray luminosities in the 2-10 keV and 14-195 keV bands that are less sensitive to galaxy contamination, and the full width at half maximum (FWHM) of the most important rest-frame near-infrared (NIR) and optical BLR emission lines. Methods: We built a sample of RM AGN with both X-ray luminosity, broad optical and NIR FWHM measurements available to calibrate new virial BH mass estimators. Results: We found that the FWHM of the Hα, Hβ, and NIR lines (i.e. Paα, Paβ, and He iλ10830) all correlate with each other with negligible or small offsets. This result allowed us to derive virial BH mass estimators based on either the 2-10 keV or 14-195 keV luminosity. We also took into account the recent determination of the different virial coefficients, f, for pseudo- and classical bulges. By splitting the sample according to the bulge type and adopting separate f factors, we found that our virial relations predict BH masses of AGN hosted in pseudo-bulges 0.5 dex smaller than in classical bulges. Assuming the same average f factor for both populations

  3. Spectral and timing properties of the black hole X-ray binary H1743–322 in the low/hard state studied with Suzaku

    SciTech Connect

    Shidatsu, M.; Ueda, Y.; Hori, T.; Yamada, S.; Done, C.; Yamaoka, K.; Kubota, A.; Nagayama, T.; Moritani, Y.

    2014-07-10

    We report on the results from Suzaku observations of the Galactic black hole X-ray binary H1743–322 in the low/hard state during its outburst in 2012 October. We appropriately take into account the effects of dust scattering to accurately analyze the X-ray spectra. The time-averaged spectra in the 1-200 keV band are dominated by a hard power-law component of a photon index of ≈1.6 with a high-energy cutoff at ≈60 keV, which is well described with the Comptonization of the disk emission by the hot corona. We estimate the inner disk radius from the multi-color disk component, and find that it is 1.3-2.3 times larger than the radius in the high/soft state. This suggests that the standard disk was not extended to the innermost stable circular orbit. A reflection component from the disk is detected with R = Ω/2π ≈ 0.6 (Ω is the solid angle). We also successfully estimate the stable disk component independent of the time-averaged spectral modeling by analyzing short-term spectral variability on a ∼1 s timescale. A weak low-frequency quasi-periodic oscillation at 0.1-0.2 Hz is detected, whose frequency is found to correlate with the X-ray luminosity and photon index. This result may be explained by the evolution of the disk truncation radius.

  4. Repeated short-term spectral softening in the low/hard state of the Galactic black hole candidate Swift J1753.5-0127

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Akifumi; Yamada, Shin'ya; Nakahira, Satoshi; Matsuoka, Masaru; Negoro, Hitoshi; Mihara, Tatehiro; Tamagawa, Toru

    2015-02-01

    We report MAXI and Swift observations of short-term spectral softenings of the Galactic black hole X-ray binary Swift J1753.5-0127 in the low/hard state. These softening events are characterized by a simultaneous increase of soft X-rays (2-4 keV) and a decrease of hard X-rays (15-50 keV) lasting for a few tens of days. The X-ray energy spectra during the softening periods can be reproduced with a model consisting of a multi-color disk blackbody and its Comptonized component. The fraction of the Comptonized component decreased from 0.30 to 0.15 when the spectrum became softer; meanwhile the inner disk temperature (Tin) increased from 0.2 to 0.45 keV. These results imply that the softening events are triggered by a short-term increase of the mass accretion rate. During the observed spectral softening events, the disk flux (Fdisk) and Tin did not obey the Fdisk ∝ (Tin )4 relation, suggesting that the inner disk radius does not reach the innermost stable circular orbit.

  5. THE EFFECT OF CORONAL RADIATION ON A RESIDUAL INNER DISK IN THE LOW/HARD SPECTRAL STATE OF BLACK HOLE X-RAY BINARY SYSTEMS

    SciTech Connect

    Liu, B. F.; Taam, Ronald E. E-mail: r-taam@northwestern.edu

    2011-01-01

    Thermal conduction between a cool accretion disk and a hot inner corona can result in either evaporation of the disk or condensation of the hot corona. At low mass accretion rates, evaporation dominates and can completely remove the inner disk. At higher mass accretion rates, condensation becomes more efficient in the very inner regions, so that part of the mass accretes via a weak (initially formed) inner disk which is separated from the outer disk by a fully evaporated region at mid radii. At still higher mass accretion rates, condensation dominates everywhere, so there is a continuous cool disk extending to the innermost stable circular orbit. We extend these calculations by including the effect of irradiation by the hot corona on the disk structure. The flux which is not reflected is reprocessed in the disk, adding to the intrinsic thermal emission from gravitational energy release. This increases the seed photons for Compton cooling of the hot corona, enhancing condensation of the hot flow, and reinforcing the residual inner disk rather than evaporating it. Our calculations confirm that a residual inner disk can coexist with a hard, coronally dominated spectrum over the range of 0.006< m-dot <0.016 (for {alpha} = 0.2). This provides an explanation for the weak thermal component seen recently in the low/hard state of black hole X-ray binary systems.

  6. Effects of super-hard rice bread blended with black rice bran on amyloid β peptide production and abrupt increase in postprandial blood glucose levels in mice.

    PubMed

    Nakamura, Sumiko; Hara, Takashi; Joh, Toshio; Kobayashi, Atsushi; Yamazaki, Akira; Kasuga, Kensaku; Ikeuchi, Takeshi; Ohtsubo, Ken'ichi

    2017-02-01

    Alzheimer's disease and type 2 diabetes are very serious diseases with the latter having been suggested to cause the former. We prepared super-hard rice bread blended with black rice bran (SRBBB), which contained a high amount of resistant starch that showed strong inhibitory activities against β-secretase and acetylcholinesterase even after heating. Black rice bran showed greater β-secretase inhibitory activity (3.6-fold) than Koshihikari rice. The bran contained more oleic acid and anthocyanin, meaning that it is potentially a biofunctional food with a high antioxidant capacity. Furthermore, aged mice, which were fed a SRBBB diet for four weeks, showed lower amyloid β 40 peptide in the blood than mice fed a commercial diet (p < 0.01). Additionally, their initial blood glucose levels (BGLs) after 12 weeks of being fed SRBBB were significantly lower than those in the control group. Taken together, our results indicate SRBBB shows promise for inhibiting not only amyloid β production, but also abrupt increases in postprandial BGLs.

  7. Low-Luminosity AGN As Analogues of Galactic Black Holes in the Low/Hard State: Evidence from X-Ray Timing of NGC 4258

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Uttley, P.

    2005-01-01

    We present a broadband power spectral density function (PSD) measured from extensive RXTE monitoring data of the low-luminosity AGN NGC 4258, which has an accurate, maser-determined black hole mass of (3.9 plus or minus 0.1) x 10(exp 7) solar mass. We constrain the PSD break time scale to be greater than 4.5 d at greater than 90% confidence, which appears to rule out the possibility that NGC 4258 is an analogue of black hole X-ray binaries (BHXRBs) in the high/soft state. In this sense, the PSD of NGC 4258 is different to that of some more-luminous Seyferts, which appear similar to the PSDs of high/soft state X-ray binaries. This result supports previous analogies between LLAGN and X-ray binaries in the low/hard state based on spectral energy distributions, indicating that the AGN/BHXRB analogy is valid across a broad range of accretion rates.

  8. Infrared

    NASA Astrophysics Data System (ADS)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  9. A process analytical technology approach based on near infrared spectroscopy: tablet hardness, content uniformity, and dissolution test measurements of intact tablets.

    PubMed

    Blanco, Marcelo; Alcalá, Manel; González, Josep M; Torras, Ester

    2006-10-01

    Near infrared spectroscopy (NIRS) is a nondestructive analytical technique that enables simultaneous measurements of chemical composition (viz. the content in active pharmaceutical ingredient, API) and various physical properties (viz. tablet hardness and dissolution profile) in pharmaceutical tablets. In this work, partial least squares (PLS) calibration models and discriminant partial least squares (DPLS) classification models were constructed by using calibration sets consisting of laboratory samples alone. The laboratory samples were mixtures of the API and excipients that were pressed into tablets. API content, tablet hardness, and dissolution measurements of intact tablets were made by using three different calibration models that are fast--results can be obtained within a few seconds--, simple and robust--they involve minimal analyst intervention--, and clean--they use no toxic reagent and produce no toxic waste. Based on the results, the proposed NIR method is an effective alternative to current reference methods for the intended purpose. The advantages provided by NIR spectroscopy in this context confirm its potential for inclusion in process analytical technologies in the pharmaceutical industry.

  10. Mid-infrared ultrafast carrier dynamics in thin film black phosphorus

    NASA Astrophysics Data System (ADS)

    Iyer, Vasudevan; Ye, Peide; Xu, Xianfan

    2017-06-01

    Black phosphorus is emerging as a promising semiconductor for electronic and optoelectronic applications. To study fundamental carrier properties, we performed ultrafast femtosecond pump-probe spectroscopy on thin film black phosphorus mechanically exfoliated on a glass substrate. Carriers (electrons and holes) were excited to high energy levels and the process of carrier relaxation through phonon emission and recombination was probed. We used a wide range of probing wavelengths up to and across the band gap to study the evolution of the relaxation dynamics at different energy levels. Our experiments revealed a plethora of important physical phenomena. The fast relaxation time constants, associated with carrier-phonon scattering, steadily increase as the energy of the probe beam approaches the band gap energy, which was determined to be 0.31 eV, and the carrier recombination rate was obtained when the probe wavelength was tuned to match the band gap energy. The carrier-phonon scattering rates were found to be similar along the armchair and zigzag directions, therefore, the anisotropic carrier mobility reported in literature is mainly due to the difference in effective mass of carriers along different directions. The ultrafast spectroscopy data further revealed the oxidation induced surface charges. Our results highlight the importance of using the spectroscopy technique, in this case, in the mid-IR range, to uncover useful physical processes.

  11. Dusty Gas Accretion onto Massive Black Holes and Infrared Diagnosis of the Eddington Ratio

    NASA Astrophysics Data System (ADS)

    Yajima, Hidenobu; Ricotti, Massimo; Park, KwangHo; Sugimura, Kazuyuki

    2017-09-01

    Evidence for dust around supermassive black holes (SMBHs) in the early universe is strongly suggested by recent observations. However, the accretion mechanism of SMBHs in dusty gas is not well understood yet. We investigate the growth of intermediate-mass black holes (IMBHs) of ˜ {10}4{--}{10}6 {M}⊙ in dusty clouds by using one-dimensional radiative-hydrodynamics simulations. We find that the accretion of dusty gas onto IMBHs proceeds gently with small fluctuations of the accretion rate, whereas that of pristine gas causes more violent periodic bursts. At dust-to-gas mass ratios similar to the solar neighborhood, the time-averaged luminosity becomes smaller than that for primordial gas by one order of magnitude and the time-averaged Eddington ratio ranges from ˜ {10}-4 to ˜ {10}-2 in clouds with initial gas densities of {n}{{H}}=10{--}1000 {{cm}}-3. Our calculations show that the effect of dust opacity alone is secondary compared to the radiation pressure on dust in regulating the BH growth. We also derive spectral energy distributions at IR bands by calculating dust thermal emission and show that the flux ratio between λ ≲ 20 μ {{m}} and ≳ 100 μ {{m}} is closely related to the Eddington ratio. Thermal emission from hot dust near the BH dominates only during the phase of high accretion, producing higher flux density at ≲ 20 μ {{m}}. Therefore, we suggest that a combination of mid-IR observations by the James Webb Space Telescope and far-IR observations by ALMA or Spitzer can be used to estimate the Eddington ratio of massive BHs. We also extend our simple modeling to SMBHs of {10}8{--}{10}9 {M}⊙ and show that ALMA can detect SMBHs of ˜ {10}9 {M}⊙ at z≳ 5.

  12. Temporal evolution of liquid-assisted hard bio-tissue ablation with infrared pulsed lasers under a liquid environment

    NASA Astrophysics Data System (ADS)

    Chen, Faner; Li, Qiang; Hua, Mingxin; Zhan, Zhenlin; Xie, Shusen; Zhang, Xianzeng

    2016-10-01

    Liquid-assisted hard biotissue ablation with the pulsed lasers takes advantages in precision and compatibility than mechanical tools in traditional surgery. The objective of this study was to monitor the dynamic process of the cavitation bubble evolution induced by Ho:YAG laser under water and identify the opening time of channel formation between the fiber tip to the target tissue surface. A free-running Ho:YAG laser was used in the experiment. The wavelength was 2.1 μm with a pulse duration of 350 us and pulse energy varied from 500 mJ to 2000 mJ. The high-speed camera (PCO. dimax, Germany, PCO) applied to monitor the whole ablation process was setting at a frame rate of 52000 frames/s. The results showed that the cavitation bubble induced by laser energy experienced an oscillation process including occurrence, expansion, contraction and subsequent collapse. A channel connected the fiber tip and target tissue surface was formed during the dynamic process which allowed the following pulse energy transmitted through the channel with a relative low absorption and directly interacted with the target tissue. The beginning time of channel formation, as well as the duration of channel opening, as functions of incident laser energy were also presented. A micro-explosion was observed near the tissue surface during the bubble collapse, which may contribute to produce a clean cut, reduce the thermal injury and improve the morphology of ablation crater.

  13. A MODEL FOR THE CORRELATION OF HARD X-RAY INDEX WITH EDDINGTON RATIO IN BLACK HOLE X-RAY BINARIES

    SciTech Connect

    Qiao, Erlin; Liu, B. F.

    2013-02-10

    Observations show that there is a positive correlation between the Eddington ratio {lambda} and hard X-ray index {Gamma} for {lambda} {approx}> 0.01, and there is an anti-correlation between {lambda} and {Gamma} for {lambda} {approx}< 0.01 in black hole X-ray binaries (with {lambda} = L {sub bol}/L {sub Edd}). In this work, we theoretically investigate the correlation between {Gamma} and {lambda} within the framework of a disk-corona model. We improve the model by taking into account all cooling processes, including synchrotron and self-Compton radiations in the corona, Comptonization of the soft photons from the underlying accretion disk, and the bremsstrahlung radiations. Presuming that the coronal flow above the disk can reach up to the 0.1 Eddington rate at the outer region, we calculate the structure of the two-phase accretion flows and the emergent spectra for accretion rates from 0.003 to 0.1. We find that at accretion rates larger than bsim0.01 Eddington rate, a fraction of coronal gas condenses into the disk and an inner disk can be sustained by condensation. In this case, the X-ray emission is dominated by the scattering of the soft photon from the underlying disk in the corona. The emission from the inner disk and corona can produce the positive correlation between {lambda} and {Gamma}. While at accretion rates lower than bsim0.01 Eddington accretion rate, the inner disk vanishes completely by evaporation, and the accretion is dominated by advection-dominated accretion flows (ADAFs), in which the X-ray emission is produced by the Comptonization of the synchrotron and bremsstrahlung photons of ADAF itself. The emission from ADAFs can produce the anti-correlation between {lambda} and {Gamma}. We show that our model can roughly explain the observed evolution of {Gamma}{sub 3-25keV} with L {sub 0.5-25keV}/L {sub Edd} for the black hole X-ray transient H1743-322 in the decay of 2003 from the thermal-dominated state to low/hard state.

  14. Hard X-Ray Variability of the Black Hole Candidate GRO J0422+32 During its 1992 Outburst

    NASA Technical Reports Server (NTRS)

    vanderHooft, F.; Kouveliotou, C.; vanParadijs, J.; Paciesas, W. S.; Lewin, W. H. G.; Crary, D. J.; Finger, M. H.; Harmon, B. A.; Zhang, S. N.; vanderKlis, M.

    1999-01-01

    We have studied the hard X-ray variability of the soft X-ray transient GRO J0422+32 with BATSE (Burst and Transient Source Experiment) in the 20-100 keV energy band. Our analysis covers 180 days following the first X-ray detection of the source on August 5, 1992, fully covering its primary and secondary X-ray outbursts. We compute power density spectra (PDSs) in the 20-50, 50-100, and 20-100 keV energy bands, in the frequency interval 0.002-0.488 Hz. The PDSs of GRO J0422+32 are approximately flat up to a break frequency, and decay as a power law above it, with index approximately 1. During the first 70 days of the X-ray outburst, the PDSs of GRO J0422+32 show a significant quasi-periodic oscillation (QPO) peak near approximately 0.2 Hz, superposed on the power-law tail. The break frequency of the PDSs obtained during the primary X-ray outburst of GRO J0422+32 occurs at 0.041 +/- 0.006 Hz; during the secondary outburst, the break is at 0.081 +/- 0.015 Hz. The power density at the break ranged between 44% and 89% / square root of Hz (20-100 keV). The canonical anticorrelation between the break frequency and the power density at the break, observed in Cyg X-1 and other BHCs in the low state, is not observed in the PDSs of GRO J0422+32. We compare our results with those of similar variability studies of Cyg X-1. The relation between the spectral slope and the amplitude of the X-ray variations of GRO J0422+32 is similar to that of Cyg X-1; however, the relation between the hard X-ray flux and the amplitude of its variation is opposite to what has been found in Cyg X-1. Phase lags between the X-ray flux variations of GRO J0422+32 at high and low photon energies could only be derived during the first 30 days of its outburst. During this period, the variations in the 50-100 keV band lag those in the 20-50 keV energy band by an approximately constant phase difference of 0.039(3) rad in the frequency interval 0.02-0.20 Hz. The time lags of GRO J0422+32 during the first 30

  15. Hard X-Ray Variability of the Black Hole Candidate GRO J0422+32 During its 1992 Outburst

    NASA Technical Reports Server (NTRS)

    VanderHooft, F.; Kouveliotou, C.; VanParadijs, J.; Paciesas, W. S.; Lewin, W. H. G.; VanderKlis, M.; Crary, D. J.; Finger, M. H.; Harmon, B. A.; Zhang, S. N.

    1998-01-01

    We have studied the hard X-ray variability of the soft X-ray transient GRO J0422+32 with the Burst and Transient Source Experiment (BATSE) in the 20-100 keV energy band. Our analysis covers 180 days following the first X-ray detection of the source on 1992 August 3, fully covering its primary and secondary X-ray outburst. We computed power density spectra (PDSS) in the 20-50, 50-100, and 20-100 keV energy bands., in the frequency interval 0.002-0.488 Hz. The PDSs of GRO J0422+32 are approximately flat up to a break frequency and decay as a power law above, with index about 1. During the first 70 days of the X-ray outburst, the PDSs of GRO J0422+32 show a significant QPO Peak near about 0.2 Hz, superposed on the power-law tail. The break frequency of the PDSs obtained during the primary X-ray outburst of GRO J0422+32 occurs at 0.041+/-0.006 Hz; during the secondary outburst the break is at 0.081q0.01.5 Hz. The power density at the break ranged between 44 and 89% Hz(exp -1/2) 20-100 keV). The canonical anticorrelation between the break frequency and the power density at the break, observed in Cyg X-1 and other BHCs in the low state, is not observed in the PDSs of GRO J0422+32. We compare our results with those of similar variability studies of Cyg X-1. The relation between the spectral slope and the amplitude of the X-ray variations of GRO J0422+32 is similar to that of Cyg X-1.

  16. Use of color, color infrared, black and white films, and video systems in detecting health, stress, and disease in vegetation

    NASA Astrophysics Data System (ADS)

    Blazquez, Carlos H.

    1991-02-01

    Ground and aerial experiments were conducted with color (NC) color infrared (CIR) and black and white film and video systems to compare the limitations! advantages of each method of image acquisition with photographs of natural vegetation including cypress stands wetlands and cultivated crops such as: tomatoes cucumbers and citrus. Image analysis with a Linear Measuring System (LMS) and a scanning densitometer were used to quantify healthy stressed and diseased foliage!canopy of each crop for comparisons with visual estimates. videography and photography were useful in delineating topographic features and location of vegetation. The NC video systems yielded images that distinctly separated healthy and dying foliage but did not compare with the CIR video or photography in outlining distinct areas of stress and disease. Aerial photography provided a synoptic view of the fields and cypress stands not otherwise possible. CIR images were easier to process with the LMS than NC video or photographic frames. CIR video and photographic systems produced clearer differences between healthy and stressed foliage. Spectral curves produced with the scanning densitometer correlated well with visual grading of health and stress. . 2.

  17. Tracking a hard state radio-quiet to radio-loud transition in the black hole X-ray binary Swift J1753.5-0127

    NASA Astrophysics Data System (ADS)

    Kolehmainen, M.; Fender, R.; Miller-Jones, J.; Jonker, P.; Anderson, G.; Homan, J.; Sivakoff, G.

    2015-07-01

    A lot of effort has gone into trying to explain the two radio/X-ray correlation tracks seen in the low/hard state of black hole binaries in recent years. The standard correlation of the form L_{R}∝ L^{0.6±0.1}_{X} is clearly paired with a lower, radio-quiet track with a slope of ˜1-1.4, although a generally accepted cause for this remains unclear. We present simultaneous radio/X-ray observations of Swift J1753.5-0127, spanning over a year in time, which seem to confirm the steep-slope radio-quiet nature of the source. Our X-ray-faint sample complements previous higher luminosity observations, making Swift J1753 one of the best sampled sources in L_{X}-L_{R}. We find that the source shows possible signs of dual track behaviour, as it moves from the radio-quiet track towards the standard correlation track with decreasing X-ray flux. We discuss possible physical explanations for this behaviour, but find no obvious parameters to explain the observed transition.

  18. Explore protein molecular structure in endosperm tissues in newly developed black and yellow type canola seeds by using synchrotron-based Fourier transform infrared microspectroscopy.

    PubMed

    Theodoridou, Katerina; Vail, Sally; Yu, Peiqiang

    2014-01-01

    This study was conducted to characterize the protein molecular structure in endosperm tissues in newly developed black and yellow-type canola seeds by using synchrotron-based Fourier transform infrared microspectroscopy. The results showed that the yellow canola seeds contained relatively lower (P<0.05) percentage of β-sheet and amide I and amide II area compared to the black-type canola seed. This might be an indication that the protein value of the yellow canola seeds as food or feed is different from that of the black canola seeds. The multivariate molecular spectral analyses (AHCA, PCA) showed that there were not significant molecular structural differences in the protein amide I and amide II fingerprint region (ca. 1720-1480 cm(-1)) between the yellow and the black-type of canola seed. It can be concluded that both the yellow and the black-seeded canola contain the same proteins but in different ratios. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Investigating the Physics of Hard X-ray Outbursts from the Galactic Center Supermassive Black Hole Sagittarius A* with NuSTAR

    NASA Astrophysics Data System (ADS)

    Zhang, Shuo; NuSTAR Galactic Plane Survey Working Group

    2016-01-01

    The Galactic center supermassive black hole (SMBH) Sagittarius A* (Sgr A*) is remarkably underluminous with a bolometric luminosity about 10-9 times its Eddington luminosity. It is the closest SMBH and thus an ideal target for investigation of galactic nuclei and their activity cycles. This goal can be fulfilled by studying its current, past and possible future outbursts. Its current X-ray quiescent state, with a luminosity of LX ~ 1033 erg s-1, is punctuated by X-ray flares up to a few times 1035 erg s-1, whose origin is poorly understood. With 638.6 ks NuSTAR observation of Sgr A*, I collected nine X-ray flares which are detected up to 79 keV, and studied their timing behavior using the Bayesian block analysis. The broadband (3-79 keV) spectroscopic studies show that the X-ray flares can have a range of photon indexes, which can be explained by the magnetic reconnection scenario. During the flares, Sgr A* is still orders of magnitudes lower than its Eddington luminosity. Whether it has ever experienced more substantial increases in activity as observed in low-luminosity Active Galactic Nuclei is still under discussion. Indication of such past activity of Sgr A* has come from the Galactic center molecular clouds (GCMCs). I use the hard X-ray emission from Sgr B2, the densest GCMC, to constrain the past Sgr A* X-ray outburst, resulting in LX~5×1038 erg s-1 with a photon index of Γ=2.2±0.4. I also discovered different timing variability from different cloud substructures, which can further constrain the past Sgr A* outburst and the cloud structure. Future giant outburst from Sgr A* could be triggered by dust/gas infall. Although the G2 infall event has not caused any increased X-ray activity from Sgr A*, there has been evidence that it caused flare behavior changes. Ongoing hard X-ray monitoring of Sgr A* will address this remaining puzzle.

  20. Determining the radio active galactic nuclei contribution to the radio-far-infrared correlation using the black hole Fundamental Plane relation

    NASA Astrophysics Data System (ADS)

    Wong, O. Ivy; Koss, M. J.; Schawinski, K.; Kapińska, A. D.; Lamperti, I.; Oh, K.; Ricci, C.; Berney, S.; Trakhtenbrot, B.

    2016-08-01

    We investigate the 1.4-GHz radio properties of 92 nearby (z < 0.05) ultra-hard X-ray selected active galactic nuclei (AGNs) from the Swift Burst Alert Telescope (BAT) sample. Through the ultra-hard X-ray selection, we minimize the biases against obscured or Compton-thick AGNs as well as confusion with emission derived from star formation that typically affect AGN samples selected from the ultraviolet, optical and infrared wavelengths. We find that all the objects in our sample of nearby, ultra-hard X-ray selected AGNs are radio quiet; 83 per cent of the objects are classed as high-excitation galaxies and 17 per cent as low-excitation galaxies. While these low-z BAT sources follow the radio-far-infrared correlation in a similar fashion to star-forming galaxies, our analysis finds that there is still significant AGN contribution in the observed radio emission from these radio-quiet AGNs. In fact, the majority of our BAT sample occupy the same X-ray-radio Fundamental Plane as has been observed in other samples, which include radio-loud AGNs - evidence that the observed radio emission (albeit weak) is connected to the AGN accretion mechanism, rather than star formation.

  1. Fingerprints of the first black holes? Crosscorrelationg the Near-Infrared and X-ray background in COSMOS

    NASA Astrophysics Data System (ADS)

    Hasinger, Guenther

    Unresolved cosmic backgrounds carry information about the populations of stars and black holes not accessible by any other current observational technique. Studies using both Spitzer and AKARI have revealed large-scale fluctuations in the Cosmic Infrared Background (CIB) after subtracting resolved sources to faint levels. The signal, which is stronger than all foreground contributions, has been attributed to the earliest light in the universe. Other teams, by using Spitzer and CIBER, suggested that this signal could originate from stars tidally stripped from their parent galaxies at low redshift as a result of mergers. Only sensitive multi-wavelength observations can distinguish between these radically different interpretations. Recently our team discovered an intriguing cross-correlation signal between the unresolved CIB and X-ray background (CXB) suggesting significant black hole populations among the CIB sources (C13). The analysis used data from Spitzer and Chandra in an overlapping 8'x45' region of the All-Wavelength Extended Groth strip International Survey (AEGIS), probing the clustering of the underlying sources to angular scales 20', but the experiment is limited by the size and the elongated configuration of the field. Here we propose to use the much more extended multiwavelength observations in the COSMOS field to obtain new constraints on this important debate. Spitzer has recently completed the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH), which observed the full 2 square degree COSMOS field to about half the depth of the AEGIS field, but a 20 times larger sky area. SPLASH, focusing on the COSMOS field with excellent multi-wavelength coverage from space and ground-based observatories, is ideally suited to study the CIB to better precision and at larger scales than available so far. We propose to cross-correlate the Spitzer unresolved CIB to the unresolved CXB observed by Chandra and XMM-Newton. Chandra has covered the full 2 deg2 COSMOS

  2. SPATIALLY RESOLVED [Fe II] 1.64 {mu}m EMISSION IN NGC 5135: CLUES FOR UNDERSTANDING THE ORIGIN OF THE HARD X-RAYS IN LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Colina, L.; Pereira-Santaella, M.; Alonso-Herrero, A.; Arribas, S.; Bedregal, A. G.

    2012-04-20

    Spatially resolved near-IR and X-ray imaging of the central region of the luminous infrared galaxy (LIRG) NGC 5135 is presented. The kinematical signatures of strong outflows are detected in the [Fe II] 1.64 {mu}m emission line in a compact region at 0.9 kpc from the nucleus. The derived mechanical energy release is consistent with a supernova rate of 0.05-0.1 yr{sup -1}. The apex of the outflowing gas spatially coincides with the strongest [Fe II] emission peak and with the dominant component of the extranuclear hard X-ray emission. All these features provide evidence for a plausible direct physical link between supernova-driven outflows and the hard X-ray emitting gas in an LIRG. This result is consistent with model predictions of starbursts concentrated in small volumes and with high thermalization efficiencies. A single high-mass X-ray binary (HMXB) as the major source of the hard X-ray emission, although not favored, cannot be ruled out. Outside the active galactic nucleus, the hard X-ray emission in NGC 5135 appears to be dominated by the hot interstellar medium produced by supernova explosions in a compact star-forming region, and not by the emission due to HMXBs. If this scenario is common to (ultra)luminous infrared galaxies, the hard X-rays would only trace the most compact ({<=}100 pc) regions with high supernova and star formation densities, therefore a lower limit to their integrated star formation. The star formation rate derived in NGC 5135 based on its hard X-ray luminosity is a factor of two and four lower than the values obtained from the 24 {mu}m and soft X-ray luminosities, respectively.

  3. The discrimination potential of ultraviolet-visible spectrophotometry, thin layer chromatography, and Fourier transform infrared spectroscopy for the forensic analysis of black and blue ballpoint inks.

    PubMed

    Causin, Valerio; Casamassima, Rosario; Marega, Carla; Maida, Pietro; Schiavone, Sergio; Marigo, Antonio; Villari, Antonino

    2008-11-01

    The knowledge of the discriminating power of analytical techniques used for the differentiation of writing inks can be useful when interpreting results. Ultraviolet-visible (UV-VIS) spectrophotometry, thin layer chromatography (TLC), and diffuse reflectance Fourier transform infrared spectroscopy (FT-IR) were used to examine a population of 21 black and 12 blue ballpoint writing inks. Based on corroborative results of these methods, the discrimination power for UV-VIS, TLC, and FT-IR was determined to be 100% and 98% for the black and blue inks, respectively. Generally, TLC and UV-VIS can be used to differentiate the colorant components (i.e., dyes and some pigments) found in inks. As FT-IR can be utilized to identify some of the noncolorant components, it was determined to be an excellent complementary technique that can be implemented into an analytical scheme for ink analysis.

  4. Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers

    PubMed Central

    Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

    2016-01-01

    Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers. PMID:27457338

  5. Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers.

    PubMed

    Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

    2016-07-26

    Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers.

  6. Hardness testing

    SciTech Connect

    Not Available

    1987-01-01

    This technical manual is a handbook dealing with all aspects of hardness testing. Every hardness testing method is fully covered, from Rockwell to ultrasonic hardness testing. Specific hardness testing problems are also discussed, and methods are offered for many applications. One chapter examines how to select the correct hardness testing method. A directory of manufacturers, distributors and suppliers of hardness testing equipment and supplies in the United States and Canada is also included. The book consist of eight chapters and an appendix. It discusses common concepts of hardness, and the theories and methods of hardness testing. Coverage includes specific hardness testing methods - Brinell, Rockwell, Vickers, and microhardness testing; and other hardness testing methods, such as scleroscope, ultrasonic, scratch and file testing, and hardness evaluation by eddy current testing.

  7. Chemical composition of contemporary black printing inks based on infrared spectroscopy: basic information for the characterization and discrimination of artistic prints.

    PubMed

    Vila, Anna; Ferrer, Núria; García, Jose F

    2007-05-15

    This article aims to provide the basic information necessary to afford the discrimination of artistic prints based on chemical information. The presence of original and non-original prints in the art market is a real problem, especially for contemporary artists. Most of the non-original elements can be distinguished on the basis of their stylistics and printing characteristics, but sometimes this information is not enough. To facilitate discrimination in these cases, we propose to add, to the previously indicated aspects, the chemical information of the materials involved in the production of the original series (inks, paper and pencil). Comparison of the composition of any element with that established for the original series will permit the attribution of any doubtful element. This article is focused on the evaluation of this approach by determining the chemical composition of contemporary black printing inks by infrared spectroscopy and by searching, on the basis of the information obtained, for criteria capable to discriminate between prints made of different inks. The success of the approach with this set of inks could easily be extended to the study of colour inks. The study also includes the characterization and discrimination of black pigments because they are the most characteristic component of these inks and because this information can also be useful for other artistic studies. The procedure proposed permits the analysis of inks with minimum deterioration of the artwork. Results indicate the capability of the approach because, following the procedure, it is possible to distinguish between black pigments attending to the presence of hydroxyapatite, silicate and some other specific bands, whereas black inks can be discriminated by paying attention to the inclusion in their composition of such pigments as bone black, Prussian blue, mars brown or other specific bands. Scanning electron microscopy analyses have corroborated the results obtained.

  8. [Prediction of soil organic carbon in different soil fractions of black soils in Northeast China using near-infrared reflectance spectroscopy].

    PubMed

    Fan, Ru-qin; Yang, Xue-ming; Zhang, Xiao-ping; Shen, Yan; Liang, Ai-zhen; Shi, Xiu-huan; Wei, Shou-cai; Chen, Xue-wen

    2012-02-01

    The soil organic carbon (SOC) associated with different soil fractions varies in the composition and dynamics. The present work is aimed to evaluate the potential of near infrared spectroscopy (NIRS) to predict SOC content in different soil fractions of black soils. SOC contents of 136 black soil samples in China were analyzed and the NIR spectra were collected using a VECTOR/22 (Fourier transform infrared spectroscopy). Partial least squares (PLS) regression with cross validation was used to develop calibrations between reference data and NIRS spectra (n = 100) which were validated using an independent set of samples (n = 36). Predictions for water-sieved aggregate associated organic carbon were generally good with R2 (coefficient of determination) ranging from 0.69 to 0.82 and the RPD (residual prediction deviation) from 1.2 to 1.8. NIRS well predicted the SOC in < 53 microm mineral fraction (R2 = 0.97, RPD = 5.4), but the prediction for SOC in 250-2 000 microm or in 53-250 microm particulate matter fractions was poor. However, the prediction for the SOC in 53-2 000 microm fraction was good (R2 = 0.79, RPD = 2.2). In addition, NIRS very well predicted the SOC in fine particle fraction (< 20 microm) (R2 = 0.93, RPD = 3.8). Accordingly, NIRS showed a good potential to predict SOC in some soil fractions and could reduce tedious laboratory analysis.

  9. Evaluation of canning quality traits in black beans (Phaseolus vulgaris L.) by visible/near-infrared spectroscopy

    USDA-ARS?s Scientific Manuscript database

    Black bean (Phaseolus vulgaris L.) processing presents unique challenges because of discoloration, breakage, development of undesirable textures and off-flavors during canning and storage. These quality issues strongly affect processing standards and consumer acceptance for beans. In this research, ...

  10. Monitoring decay of black gum wood (Nyssa sylvatica) during growth of the shiitake mushroom (Lentinula edodes) using diffuse reflectance infrared spectroscopy.

    PubMed

    Vane, Christopher H

    2003-05-01

    Abstract diffuse reflectance infrared spectroscopy (DRIFT) and elemental analysis were employed to monitor biodegradation of black gum wood (Nyssa sylvatica) during growth of the shiitake mushroom (Lentinula edodes). Black gum was decayed for up to 4.3 years by L. edodes, during which time it was sampled at 19, 31, and 52 months. Biodegraded woods displayed increased % O (w/w) and decreased % C (w/w) relative to the undecayed control. The DRIFT spectra of decayed black gum showed a decrease in relative intensity of absorption bands at 1735 cm(-1) assigned to carboxyl functional groups from xylans and an increase in the absorption band at 1640 cm(-1) assigned to conjugated carbonyl groups originating from lignin. Xylan decay was rapid initially but slowed after 19 months; however, oxidative decay of the lignin side chains occurred throughout the 52-month decay period. Overall elemental and DRIFT data show that both polysaccharides and lignin were decayed during cultivation of the edible white-rot fungus.

  11. Multi-frequency studies of Galactic X-ray sources populations. Hard X-ray Galactic sources of low to intermediate L_X A search for isolated accreting black holes

    NASA Astrophysics Data System (ADS)

    Motch, C.; Pakull, M. W.

    Our Galaxy harbours a large population of X-ray sources of intermediate to low X-ray luminosity (typically L_X from 1027 to 1034 erg s-1). At energies below 2 keV, active coronae completely dominate the X-ray landscape. However, the nature and the properties of the Galactic sources detected at energies ga 2 keV is much less constrained. Optical follow-up spectroscopic observations show that in addition to cataclysmic variables (CVs) and very active stellar coronae, massive stars (colliding wind binaries, quiescent high-mass X-ray binaries and gamma -Cas analogs) account for a sizable fraction of the Galactic hard X-ray sources at medium flux (F_X ga 10-13 erg s-1cm). Cross-correlations of the 2XMM-DR3 catalogue with 2MASS and GLIMPSE confirm the presence above 2 keV of a large population of coronally active binaries, probably of the BY Dra and RS CVn types, in addition to many distant and absorbed massive stars. We also report the results of a specific optical identification campaign aiming at studying the nature of the optically faint hard X-ray sources and at constraining the surface density of black holes (BHs), either isolated and accreting from the interstellar medium or in quiescent binaries. Not astonishingly, most of our sample of 14 optically faint and X-ray hard sources are identified with CVs and Me stars. We do not find any likely counterpart in only three cases. Our observations also allow us to put an upper limit of 0.2 BH deg-2 at F_X = 1.3 10-13 erg s-1cm in directions toward the center of our Galaxy. This implies a combined Bondi-Hoyle and dotM to L_X efficiency of accretion onto black holes of less than 10-3.

  12. Metal-Free Photocatalyst for H2 Evolution in Visible to Near-Infrared Region: Black Phosphorus/Graphitic Carbon Nitride.

    PubMed

    Zhu, Mingshan; Kim, Sooyeon; Mao, Liang; Fujitsuka, Mamoru; Zhang, Junying; Wang, Xinchen; Majima, Tetsuro

    2017-09-20

    In the drive toward green and sustainable chemistry, exploring efficient and stable metal-free photocatalysts with broadband solar absorption from the UV to near-infrared region for the photoreduction of water to H2 remains a big challenge. To this end, a binary nanohybrid (BP/CN) of two-dimensional (2D) black phosphorus (BP) and graphitic carbon nitride (CN) was designed and used as a metal-free photocatalyst for the first time. During irradiation of BP/CN in water with >420 and >780 nm light, solid H2 gas was generated, respectively. Owing to the interfacial interaction between BP and CN, efficient charge transfer occurred, thereby enhancing the photocatalytic performance. The efficient charge-trapping and transfer processes were thoroughly investigated with time-resolved diffuse reflectance spectroscopic measurement. The present results show that BP/CN is a metal-free photocatalyst for artificial photosynthesis and renewable energy conversion.

  13. Dual-wavelength Q-switched Er:SrF2 laser with a black phosphorus absorber in the mid-infrared region.

    PubMed

    Liu, Jingjing; Liu, Jie; Guo, Zhinan; Zhang, Han; Ma, Weiwei; Wang, Jingya; Su, Liangbi

    2016-12-26

    An efficient Er:SrF2 crystal, lightly Er-doped to a concentration of 4at.%, was successfully grown by the traditional Bridgman method and displayed excellent spectral properties. A diode-end-pumped passively Q-switched dual-wavelength laser, operating at 2.79 μm wavelength, was demonstrated with this crystal by using black phosphorus as the saturable absorber (BP-SA). In the compact passively Q-switched Er:SrF2 laser, the maximum average output power of 180 mW was achieved at an absorbed pump power of 2.47 W, with a pulse duration of 702 ns and a repetition rate of 77.03 kHz. To the best of our knowledge, this is the first reported application of BP-SA to dual-wavelength pulse laser operation in the mid-infrared region.

  14. It's Hard to Be Who You Don't See: An Exploration of Black Male High School Students' Perspectives on Becoming Teachers

    ERIC Educational Resources Information Center

    Goings, Ramon B.; Bianco, Margarita

    2016-01-01

    The goal of this qualitative study was to explore the perspectives of high school age Black males (N = 22) regarding factors that influence or deter their consideration of becoming teachers. Participants were enrolled in a yearlong, pre-collegiate course designed to introduce high school students to the teaching profession. Qualitative analysis of…

  15. It's Hard to Be Who You Don't See: An Exploration of Black Male High School Students' Perspectives on Becoming Teachers

    ERIC Educational Resources Information Center

    Goings, Ramon B.; Bianco, Margarita

    2016-01-01

    The goal of this qualitative study was to explore the perspectives of high school age Black males (N = 22) regarding factors that influence or deter their consideration of becoming teachers. Participants were enrolled in a yearlong, pre-collegiate course designed to introduce high school students to the teaching profession. Qualitative analysis of…

  16. Flaring Black Hole Artist Concept

    NASA Image and Video Library

    2011-09-20

    This artist concept illustrates what the flaring black hole called GX 339-4 might look like. Infrared observations from NASA WISE reveal the best information yet on the chaotic and extreme environments of this black hole jets.

  17. Black layers on historical architecture.

    PubMed

    Toniolo, Lucia; Zerbi, Carlotta M; Bugini, Roberto

    2009-03-01

    The external surface of any building in urban polluted environment is unavoidably destined to be covered with layers that assume a grey to black colour and are generally called 'black crusts'. These, according to standard protocols and glossary, are deteriorated surface layers of stone material; they can have variable thickness, are hard and fragile and can detach spontaneously from the substrate, which, in general, is quite decayed. Plain visual examination may lead to consider 'black crusts' all similar, whilst only a careful diagnostic investigation can distinguish 'black crusts' and the consequences of their formation on stone substrates. In this paper, various black layers on marble are studied and compared and the morphological and compositional characteristics discussed according to the related mechanisms of formation. Differences between old (hundred years) and recent crusts (30 years) are investigated and pointed out. Samples of black crusts collected from the Milan Cathedral façade (Candoglia Marble) have been studied and compared with the careful and synergic employ of traditional techniques: optical (transmission and reflected VIS light) and electron microscopy, X-ray spectrometry and micro-Fourier transform infrared spectroscopy. Visual examination of loose fragments does not allow to point out outstanding differences amongst the various samples; black layers have similar main mineral components, gypsum and airborne particles, with different spatial distribution. The microscopic studies allowed to point out the porosity differences, the gypsum crystallisation habit, different amount of embedded particles, level and progress of marble decay. The observations lead to define three main types of black crusts: black crust deriving from marble sulphation, compact deposit and encrustation due to exogenic materials deposition. Black crusts show evidence of sulphation in progress, without a clear continuity solution between crust and marble; the lack of

  18. A New Deep, Hard X-ray Survey of M31: Monitoring Black Hole and Neutron Star Accretion States in the X-ray Binary Population of Our Nearest Neighbor

    NASA Astrophysics Data System (ADS)

    Wik, Daniel R.; Hornschemeier, Ann E.; Yukita, Mihoko; Ptak, Andrew; Lehmer, Bret; Maccarone, Thomas J.; Antoniou, Vallia; Zezas, Andreas; Harrison, Fiona; Stern, Daniel; Venters, Tonia M.; Williams, Benjamin F.; Eracleous, Michael; Plucinsky, Paul P.; Pooley, David A.

    2016-01-01

    X-ray binaries (XRBs) trace old and new stellar populations in galaxies, and thus star formation history and star formation rate. X-ray emission from XRBs may be responsible for significant amounts of heating of the early Intergalactic Medium at Cosmic Dawn and may also play a significant role in reionization. Until recently, the hard emission from these populations could only be studied for XRBs in our own galaxy, where it is often difficult to measure accurate distances and thus luminosities. The launch of NuSTAR, the first focusing hard X-ray observatory, has allowed us to resolve the brightest XRBs (down to LX ~ few times 1038 erg/s) in galaxies like NGC 253, M83, and M82 up to 4 Mpc away. To reach much lower X-ray luminosities that are more typical of XRBs in the Milky Way (LX <~ 1037 erg/s), we have observed M31 in 3 NuSTAR fields, up to 5 visits apiece for more than 1 Ms total exposure, mostly within the footprint of the Panchromatic Hubble Andromeda Treasury (PHAT) Survey. Our monitoring campaign reveals over 40 accreting black holes and neutron stars -- distinguished from each other by their spectral shape in the hard band -- some of which undergo state changes over the month-long timescales captured by our legacy survey to date. We also discuss implications for this updated understanding of XRB populations on early-Universe measurements in, e.g., the 7 Ms Chandra Deep Field survey.

  19. Very black infrared detector from vertically aligned carbon nanotubes and electric-field poling of lithium tantalate.

    PubMed

    Lehman, John; Sanders, Aric; Hanssen, Leonard; Wilthan, Boris; Zeng, Jinan; Jensen, Christopher

    2010-09-08

    Vertically aligned multiwall carbon nanotubes were grown by water-assisted chemical vapor deposition on a large-area lithium tantalate pyroelectric detector. The processing parameters are nominally identical to those by which others have achieved the "world's darkest substance" on a silicon substrate. The pyroelectric detector material, though a good candidate for such a coating, presents additional challenges and outcomes. After coating, a cycle of heating, electric field poling, and cooling was employed to restore the spontaneous polarization perpendicular to the detector electrodes. The detector responsivity is reported along with imaging as well as visible and infrared reflectance measurements of the detector and a silicon witness sample. We find that the detector responsivity is slightly compromised by the heat of processing and the coating properties are substrate dependent. However, it is possible to achieve nearly ideal values of detector reflectance uniformly less than 0.1% from 400 nm to 4 microm and less than 1% from 4 to 14 microm.

  20. Hard tooth tissue removal by short and long Er:YAG or Er,Cr:YSGG mid-infrared laser radiation

    NASA Astrophysics Data System (ADS)

    Jelínková, H.; Dostálová, T.; Remeš, M.; Šulc, J.; Němec, M.; Fibrich, M.

    2017-02-01

    Hard dental tissue removal by laser radiation is an alternative treatment to conventional dental-drilling procedures. The advantages of this therapy are fast and localized treatment of hard dental tissue and painlessness. The most effective systems for those purposes are Er-lasers generating radiation at wavelengths of around 3 μm. The aim of this study was qualitative and quantitative examination of human dentin and ivory tissue removal by pulsed free-running (FR) and Q-switched (QSW) Er:YAG and Er,Cr:YSGG laser radiations. From the obtained results it follows that generally Er:YAG laser has lower threshold for the tissue removal in both FR and QSW regimes. Furthermore, the FR Er:YAG and Er,Cr:YSGG radiation can be effective for both dentin and ivory ablation and can prepare smooth cavities without side effects. The QSW regime is useful preferably for precise ablation of a starting tooth defect and for the part of the tooth very close to the gum. This regime is excellent for micro-preparation or for tooth treatment of children.

  1. Feasibility study on identification of green, black and Oolong teas using near-infrared reflectance spectroscopy based on support vector machine (SVM)

    NASA Astrophysics Data System (ADS)

    Chen, Quansheng; Zhao, Jiewen; Fang, C. H.; Wang, Dongmei

    2007-03-01

    Near-infrared (NIR) spectroscopy has been successfully utilized for the rapid identification of green, black and Oolong teas. The spectral features of each category are reasonably differentiated in the NIR region, and the spectral differences provided enough qualitative spectral information for identification. Support vector machine as a pattern recognition was applied to attain the differentiation of the three tea categories in this study. The top five latent variables are extracted by principal component analysis as the input of SVM classifiers. The identification results of the three tea categories were achieved by the RBF SVM classifiers and the polynomial SVM classifiers in different parameters. The best identification accuracies were up to 90%, 100% and 93.33%, respectively, when training, while, 90%, 100% and 95% when test. It was obtained using the RBF SVM classifier with σ = 0.5. The overall results ensure that NIR spectroscopy combined with SVM discrimination method can be efficiently utilized for rapid and simple identification of the different tea categories.

  2. Feasibility study on identification of green, black and Oolong teas using near-infrared reflectance spectroscopy based on support vector machine (SVM).

    PubMed

    Chen, Quansheng; Zhao, Jiewen; Fang, C H; Wang, Dongmei

    2007-03-01

    Near-infrared (NIR) spectroscopy has been successfully utilized for the rapid identification of green, black and Oolong teas. The spectral features of each category are reasonably differentiated in the NIR region, and the spectral differences provided enough qualitative spectral information for identification. Support vector machine as a pattern recognition was applied to attain the differentiation of the three tea categories in this study. The top five latent variables are extracted by principal component analysis as the input of SVM classifiers. The identification results of the three tea categories were achieved by the RBF SVM classifiers and the polynomial SVM classifiers in different parameters. The best identification accuracies were up to 90%, 100% and 93.33%, respectively, when training, while, 90%, 100% and 95% when test. It was obtained using the RBF SVM classifier with sigma=0.5. The overall results ensure that NIR spectroscopy combined with SVM discrimination method can be efficiently utilized for rapid and simple identification of the different tea categories.

  3. Au/La2 Ti2 O7 Nanostructures Sensitized with Black Phosphorus for Plasmon-Enhanced Photocatalytic Hydrogen Production in Visible and Near-Infrared Light.

    PubMed

    Zhu, Mingshan; Cai, Xiaoyan; Fujitsuka, Mamoru; Zhang, Junying; Majima, Tetsuro

    2017-02-13

    Efficient utilization of solar energy is a high-priority target and the search for suitable materials as photocatalysts that not only can harvest the broad wavelength of solar light, from UV to near-infrared (NIR) region, but also can achieve high and efficient solar-to-hydrogen conversion is one of the most challenging missions. Herein, using Au/La2 Ti2 O7 (BP-Au/LTO) sensitized with black phosphorus (BP), a broadband solar response photocatalyst was designed and used as efficient photocatalyst for H2 production. The optimum H2 production rates of BP-Au/LTO were about 0.74 and 0.30 mmol g(-1)  h(-1) at wavelengths longer than 420 nm and 780 nm, respectively. The broad absorption of BP and plasmonic Au contribute to the enhanced photocatalytic activity in the visible and NIR light regions. Time-resolved diffuse reflectance spectroscopy revealed efficient interfacial electron transfer from excited BP and Au to LTO which is in accordance with the observed high photoactivities.

  4. Black hollow silicon oxide nanoparticles as highly efficient photothermal agents in the second near-infrared window for in vivo cancer therapy.

    PubMed

    Yu, Xujiang; Yang, Kai; Chen, Xiaoyuan; Li, Wanwan

    2017-10-01

    Semiconductor nanoparticles with localized surface plasmon resonance (LSPR) have gained increasing interest due to their potential for use in nanomedicine, particularly in the area of cancer photothermal therapy. In this study, we have synthesized non-stoichiometric hollow silicon oxide nanoparticles (H-SiOx NPs) using a magnesiothermic reduction process. The black NPs generated a desired LSPR in the second near-infrared (NIR-II) window, as was demonstrated by a photothermal conversion efficiency of up to 48.6% at 1064 nm. Such an efficiency is the highest reported among the noble metal and semiconductor-based NPs as NIR-II PTT photothermal agents. In addition, H-SiOx NPs exhibited excellent in vivo photoacoustic (PA) imaging properties, and thus can be used for highly efficient in vivo cancer treatment via irradiation with a 1064 nm laser, even at 0.6 W cm(-2). The findings described are the first to demonstrate the existence of LSPR in non-stoichiometric silicon-based nanoparticles with a low-toxicity degradation pathway for in vivo application, and provide new insights towards understanding the role of new semiconductor nanoparticles in nanomedicine. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. First Results from the 7 Ms Chandra Deep Field-South Survey: A Good Hard Look at Growing Supermassive Black Holes in the Distant Universe

    NASA Astrophysics Data System (ADS)

    Brandt, William; Chandra Deep Fields Team

    2017-01-01

    Sensitive cosmic X-ray surveys with the Chandra, XMM-Newton, and now NuSTAR observatories have revolutionized our ability to find and study distant active galactic nuclei (AGNs), the main sites of supermassive black hole growth in the Universe. I will describe some recent discoveries about the demographics, physics, and ecology of distant AGNs coming from the deepest Chandra survey to date, the 7 Ms Chandra Deep Field-South. Some specific topics covered will include (1) robust X-ray spectral and variability characterization of the AGNs producing most of cosmic accretion power; (2) the demographics of AGNs in the first galaxies as revealed by direct detection and stacking; and (3) AGN/galaxy interactions as investigated via the host properties of X-ray AGNs. I will also briefly describe other remarkable discoveries coming from this survey; e.g., measurements of the evolving X-ray binary populations of normal and starburst galaxies.

  6. EXTENDED SUBMILLIMETER EMISSION OF THE GALACTIC CENTER AND NEAR-INFRARED/SUBMILLIMETER VARIABILITY OF ITS SUPERMASSIVE BLACK HOLE

    SciTech Connect

    Garcia-Marin, M.; Eckart, A.; Witzel, G.; Bremer, M.; Kunneriath, D.; Sabha, N.; Straubmeier, C.; Weiss, A.; Zamaninasab, M.; Morris, M. R.; Schoedel, R.; Nishiyama, S.; Baganoff, F.; Karas, V.; Dovciak, M.; Duschl, W. J.; Moultaka, J.; Najarro, F.; Muzic, K.; Vogel, S. N.

    2011-09-10

    The innermost tens of parsecs of our Galaxy are characterized by the presence of molecular cloud complexes surrounding Sgr A*, the radiative counterpart of the supermassive black hole ({approx}4 x 10{sup 6} M{sub sun}) at the Galactic center. We seek to distinguish the different physical mechanisms that dominate the molecular clouds at the Galactic center, with special emphasis on the circumnuclear disk (CND). We also want to study the energy flow and model the variable emission of Sgr A*. Our study is based on NIR and submillimeter (sub-mm) observations. Using sub-mm maps, we describe the complex morphology of the molecular clouds and the circumnuclear disk, along with their masses (of order 10{sup 5}-10{sup 6} M{sub sun}), and derive also the temperature and spectral index maps of the regions under study. We conclude that the average temperature of the dust is 14 {+-} 4 K. The spectral index map shows that the 20 and 50 km s{sup -1} clouds are dominated by dust emission. Comparatively, in the CND and its surroundings the spectral indices decrease toward Sgr A* and range between about 1 and -0.6. These values are mostly explained with a combination of dust, synchrotron, and free-free emission in different ratios. The presence of non-thermal emission also accounts for the apparent low temperatures derived in these areas, indicating their unreliability. The Sgr A* light curves show significant flux density excursions in both the NIR and sub-mm domains. We have defined a classification system to account for the NIR variability of Sgr A*. Also, we have modeled on the NIR/sub-mm events. From our modeling results we can infer a sub-mm emission delay with respect to the NIR; we argue that the delay is due to the adiabatic expansion of the synchrotron source components.

  7. Extended Submillimeter Emission of the Galactic Center and Near-infrared/submillimeter Variability of Its Supermassive Black Hole

    NASA Astrophysics Data System (ADS)

    García-Marín, M.; Eckart, A.; Weiss, A.; Witzel, G.; Bremer, M.; Zamaninasab, M.; Morris, M. R.; Schödel, R.; Kunneriath, D.; Nishiyama, S.; Baganoff, F.; Dovčiak, M.; Sabha, N.; Duschl, W. J.; Moultaka, J.; Karas, V.; Najarro, F.; Mužić, K.; Straubmeier, C.; Vogel, S. N.; Krips, M.; Wiesemeyer, H.

    2011-09-01

    The innermost tens of parsecs of our Galaxy are characterized by the presence of molecular cloud complexes surrounding Sgr A*, the radiative counterpart of the supermassive black hole (~4 × 106 M sun) at the Galactic center. We seek to distinguish the different physical mechanisms that dominate the molecular clouds at the Galactic center, with special emphasis on the circumnuclear disk (CND). We also want to study the energy flow and model the variable emission of Sgr A*. Our study is based on NIR and submillimeter (sub-mm) observations. Using sub-mm maps, we describe the complex morphology of the molecular clouds and the circumnuclear disk, along with their masses (of order 105-106 M sun), and derive also the temperature and spectral index maps of the regions under study. We conclude that the average temperature of the dust is 14 ± 4 K. The spectral index map shows that the 20 and 50 km s-1 clouds are dominated by dust emission. Comparatively, in the CND and its surroundings the spectral indices decrease toward Sgr A* and range between about 1 and -0.6. These values are mostly explained with a combination of dust, synchrotron, and free-free emission in different ratios. The presence of non-thermal emission also accounts for the apparent low temperatures derived in these areas, indicating their unreliability. The Sgr A* light curves show significant flux density excursions in both the NIR and sub-mm domains. We have defined a classification system to account for the NIR variability of Sgr A*. Also, we have modeled on the NIR/sub-mm events. From our modeling results we can infer a sub-mm emission delay with respect to the NIR; we argue that the delay is due to the adiabatic expansion of the synchrotron source components. Based on observations made with ESO APEX and VLT telescopes under programme 081.B-0648(B). Based also on SCUBA/JCMT archive data, project M98AU64.

  8. Studies on Nephrite and Jadeite Jades by Fourier Transform Infrared (ftir) and Raman Spectroscopic Techniques

    NASA Astrophysics Data System (ADS)

    Tan, T. L.; Ng, L. L.; Lim, L. C.

    2013-10-01

    The mineralogical properties of black nephrite jade from Western Australia are studied by Fourier transform infrared (FTIR) spectroscopy using both transmission and specular reflectance techniques in the 4000-400 cm-1 wavenumber region. The infrared absorption peaks in the 3700-3600 cm-1 region which are due to the O-H stretching mode provides a quantitative analysis of the Fe/(Fe+Mg) ratio in the mineral composition of jade samples. The Fe/(Fe+Mg) percentage in black nephrite is found to be higher than that in green nephrite, but comparable to that of actinolite (iron-rich nephrite). This implies that the mineralogy of black nephrite is closer to actinolite than tremolite. The jade is also characterized using Raman spectroscopy in the 1200-200 cm-1 region. Results from FTIR and Raman spectroscopic data of black nephrite jade are compared with those of green nephrite jade from New Zealand and jadeite jade from Myanmar. Black nephrite appears to have a slightly different chemical composition from green nephrite. Spectra from FTIR and Raman spectroscopic techniques were found to be useful in differentiating black nephrite, green nephrite, and green jadeite jades. Furthermore, data on refractive index, specific gravity, and hardness of black nephrite jade are measured and compared with those of green nephrite and of jadeite jade.

  9. Prediction of canned black bean texture (Phaseolus vulgaris L.) from intact dry seeds using visible/near infrared spectroscopy and hyperspectral imaging data.

    PubMed

    Mendoza, Fernando A; Cichy, Karen A; Sprague, Christy; Goffnett, Amanda; Lu, Renfu; Kelly, James D

    2017-06-05

    Texture is a major quality parameter for the acceptability of canned whole beans. Prior knowledge of this quality trait before processing would be useful to guide variety development by bean breeders and optimize handling protocols by processors. The objective of this study was to evaluate and compare the predictive power of visible and near infrared reflectance spectroscopy (visible/NIRS, 400-2498 nm) and hyperspectral imaging (HYPERS, 400-1000 nm) techniques for predicting texture of canned black beans from intact dry seeds. Black beans were grown in Michigan (USA) over three field seasons. The samples exhibited phenotypic variability for canned bean texture due to genetic variability and processing practice. Spectral preprocessing methods (i.e. smoothing, first and second derivatives, continuous wavelet transform, and two-band ratios), coupled with a feature selection method, were tested for optimizing the prediction accuracy in both techniques based on partial least squares regression (PLSR) models. Visible/NIRS and HYPERS were effective in predicting texture of canned beans using intact dry seeds, as indicated by their correlation coefficients for prediction (Rpred ) and standard errors of prediction (SEP). Visible/NIRS was superior (Rpred  = 0.546-0.923, SEP = 7.5-1.9 kg 100 g(-1) ) to HYPERS (Rpred  = 0.401-0.883, SEP = 7.6-2.4 kg 100 g(-1) ), which is likely due to the wider wavelength range collected in visible/NIRS. However, a significant improvement was reached in both techniques when the two-band ratios preprocessing method was applied to the data, reducing SEP by at least 10.4% and 16.2% for visible/NIRS and HYPERS, respectively. Moreover, results from using the combination of the three-season data sets based on the two-band ratios showed that visible/NIRS (Rpred  = 0.886, SEP = 4.0 kg 100 g(-1) ) and HYPERS (Rpred  = 0.844, SEP = 4.6 kg 100 g(-1) ) models were consistently successful in predicting

  10. Infrared heating

    NASA Astrophysics Data System (ADS)

    1983-11-01

    The transfer of energy by radiation whose limits lie between 1 mm and 400 mm is indicated. The radiation used lies practically completely in the infrared region. Its use therefore depends on the thermal radiation laws (black body or integral receiver laws). These laws were derived mathematically in accordance with the properties of an ideal body, the so-called ""integral receiver'' (formerly black body). According to definition this integral receiver has the property of absorbing completely all incident electromagnetic radiation. From these the following laws were deduced: (1) All bodies with a temperature above absolute zero emit a radiation. (2) The energy emitted by the integral receiver is proportional to the 4th power of the absolute temperature. (3) The emission theoretically comprizes the whole radiation. (4) The radiation comprizing the emission spectrum does not transport the same amount of energy at every wavelength.

  11. CROSS-CORRELATING COSMIC INFRARED AND X-RAY BACKGROUND FLUCTUATIONS: EVIDENCE OF SIGNIFICANT BLACK HOLE POPULATIONS AMONG THE CIB SOURCES

    SciTech Connect

    Cappelluti, N.; Comastri, A.; Kashlinsky, A.; Mather, J. C.; Moseley, S. H.; Arendt, R. G.; Finoguenov, A.; Fazio, G. G.; Hasinger, G.; Miyaji, T.

    2013-05-20

    In order to understand the nature of the sources producing the recently uncovered cosmic infrared background (CIB) fluctuations, we study cross-correlations between the fluctuations in the source-subtracted CIB from Spitzer/IRAC data and the unresolved cosmic X-ray background from deep Chandra observations. Our study uses data from the EGS/AEGIS field, where both data sets cover an {approx_equal} 8' Multiplication-Sign 45' region of the sky. Our measurement is the cross-power spectrum between the IR and X-ray data. The cross-power signal between the IRAC maps at 3.6 {mu}m and 4.5 {mu}m and the Chandra [0.5-2] keV data has been detected, at angular scales {approx}> 20'', with an overall significance of {approx_equal} 3.8{sigma} and {approx_equal} 5.6{sigma}, respectively. At the same time we find no evidence of significant cross-correlations at the harder Chandra bands. The cross-correlation signal is produced by individual IR sources with 3.6 {mu}m and 4.5 {mu}m magnitudes m{sub AB} {approx}> 25-26 and [0.5-2] keV X-ray fluxes <<7 Multiplication-Sign 10{sup -17} erg cm{sup 2} s{sup -1}. We determine that at least 15%-25% of the large scale power of the CIB fluctuations is correlated with the spatial power spectrum of the X-ray fluctuations. If this correlation is attributed to emission from accretion processes at both IR and X-ray wavelengths, this implies a much higher fraction of accreting black holes than among the known populations. We discuss the various possible origins for the cross-power signal and show that neither local foregrounds nor the known remaining normal galaxies and active galactic nuclei can reproduce the measurements. These observational results are an important new constraint on theoretical modeling of the near-IR CIB fluctuations.

  12. Black Newspapers: Overlooked Barometers. NCRIEEO Tipsheet, Number 1.

    ERIC Educational Resources Information Center

    Columbia Univ., New York, NY. National Center for Research and Information on Equal Educational Opportunity.

    Black newspapers should not go unnoticed by school administrators, as they too often are. Black people have a long and proud history of intraracial communication. More than 200 "black" periodicals work hard at forming, leading, and interpreting for black communities. No black community is totally dependent upon the standard white-owned and…

  13. Can remote infrared cameras be used to differentiate small, sympatric mammal species? A case study of the black-tailed dusky antechinus, Antechinus arktos and co-occurring small mammals in southeast Queensland, Australia

    PubMed Central

    Dennis, Todd E.; Baker, Andrew M.

    2017-01-01

    The black-tailed dusky antechinus (Antechinus arktos) is an endangered, small carnivorous marsupial endemic to Australia, which occurs at low population density along with abundant sympatric populations of other small mammals: Antechinus stuartii, Rattus fuscipes and Melomys cervinipes. Using A. arktos as a model species, we aimed to evaluate the effectiveness of infrared digital camera traps for detecting and differentiating small mammals and to comment on the broad applicability of this methodology. We also sought to understand how the detection probabilities of our target species varied over time and characterize their activity patterns. We installed 11 infrared cameras at one of only three known sites where A. arktos occurs for five consecutive deployments. Cameras were fixed to wooden stakes and oriented vertically, 35 cm above ground, directly facing bait containers. Using this method, we successfully recorded and identified individuals from all four species of small mammal known previously in the area from live trapping, including A. arktos. This validates the effectiveness of the infrared camera type and orientation for small mammal studies. Periods of activity for all species were highly coincident, showing a strong peak in activity during the same two-hour period immediately following sunset. A. arktos, A. stuartii and M. cervinipes also displayed a strong negative linear relationship between detection probability and days since deployment. This is an important finding for camera trapping generally, indicating that routine camera deployment lengths (of one-to-two weeks) between baiting events may be too long when targeting some small mammals. PMID:28792958

  14. Can remote infrared cameras be used to differentiate small, sympatric mammal species? A case study of the black-tailed dusky antechinus, Antechinus arktos and co-occurring small mammals in southeast Queensland, Australia.

    PubMed

    Gray, Emma L; Dennis, Todd E; Baker, Andrew M

    2017-01-01

    The black-tailed dusky antechinus (Antechinus arktos) is an endangered, small carnivorous marsupial endemic to Australia, which occurs at low population density along with abundant sympatric populations of other small mammals: Antechinus stuartii, Rattus fuscipes and Melomys cervinipes. Using A. arktos as a model species, we aimed to evaluate the effectiveness of infrared digital camera traps for detecting and differentiating small mammals and to comment on the broad applicability of this methodology. We also sought to understand how the detection probabilities of our target species varied over time and characterize their activity patterns. We installed 11 infrared cameras at one of only three known sites where A. arktos occurs for five consecutive deployments. Cameras were fixed to wooden stakes and oriented vertically, 35 cm above ground, directly facing bait containers. Using this method, we successfully recorded and identified individuals from all four species of small mammal known previously in the area from live trapping, including A. arktos. This validates the effectiveness of the infrared camera type and orientation for small mammal studies. Periods of activity for all species were highly coincident, showing a strong peak in activity during the same two-hour period immediately following sunset. A. arktos, A. stuartii and M. cervinipes also displayed a strong negative linear relationship between detection probability and days since deployment. This is an important finding for camera trapping generally, indicating that routine camera deployment lengths (of one-to-two weeks) between baiting events may be too long when targeting some small mammals.

  15. Infrared imaging of varicose veins

    NASA Astrophysics Data System (ADS)

    Noordmans, Herke Jan; de Zeeuw, Raymond; Verdaasdonk, Ruud M.; Wittens, Cees H. A.

    2004-06-01

    It has been established that varicose veins are better visualized with infrared photography. As near-infrared films are nowadays hard to get and to develop in the digital world, we investigated the use of digital photography of varicose veins. Topics that are discussed are illumination setup, photography and digital image enhancement and analysis.

  16. Thermopile detector radiation hard readout

    NASA Astrophysics Data System (ADS)

    Gaalema, Stephen; Van Duyne, Stephen; Gates, James L.; Foote, Marc C.

    2010-08-01

    The NASA Jupiter Europa Orbiter (JEO) conceptual payload contains a thermal instrument with six different spectral bands ranging from 8μm to 100μm. The thermal instrument is based on multiple linear arrays of thermopile detectors that are intrinsically radiation hard; however, the thermopile CMOS readout needs to be hardened to tolerate the radiation sources of the JEO mission. Black Forest Engineering is developing a thermopile readout to tolerate the JEO mission radiation sources. The thermal instrument and ROIC process/design techniques are described to meet the JEO mission requirements.

  17. Black-to-Transmissive Electrochromism with Visible-to-Near-Infrared Switching of a Co(II)-Based Metallo-Supramolecular Polymer for Smart Window and Digital Signage Applications.

    PubMed

    Hsu, Chih-Yu; Zhang, Jian; Sato, Takashi; Moriyama, Satoshi; Higuchi, Masayoshi

    2015-08-26

    Black-to-transmissive electrochromism has been obtained with a Co(II)-based metallo-supramolecular polymer (polyCo). Thin films of polyCo, based on bisterpyridine ligand assembled with Co(II) metal ion, were constructed by spray casting the polymer onto ITO glass. With such simple fabricating means to form good-quality films, polyCo films show stable switching at the central metal ion of the Co(II)/Co(I) redox reaction when immersed in aqueous solution. With an increase in the pH of the aqueous electrolyte solution from neutral, the film exhibits a color response due to the interaction between the d-orbital electron and hydroxide ions affecting the d-d* transition. As a result, a nearly transparent-to-black electrochromic performance can be achieved with a transmittance difference at 550 nm of 74.3% (81.9-7.6%) in pH 13 solution. The light absorption of the film can be tuned over light regions from visible to near-infrared with a large attenuation.

  18. Intelligent evaluation of color sensory quality of black tea by visible-near infrared spectroscopy technology: A comparison of spectra and color data information

    NASA Astrophysics Data System (ADS)

    Ouyang, Qin; Liu, Yan; Chen, Quansheng; Zhang, Zhengzhu; Zhao, Jiewen; Guo, Zhiming; Gu, Hang

    2017-06-01

    Instrumental test of black tea samples instead of human panel test is attracting massive attention recently. This study focused on an investigation of the feasibility for estimation of the color sensory quality of black tea samples using the VIS-NIR spectroscopy technique, comparing the performances of models based on the spectra and color information. In model calibration, the variables were first selected by genetic algorithm (GA); then the nonlinear back propagation-artificial neural network (BPANN) models were established based on the optimal variables. In comparison with the other models, GA-BPANN models from spectra data information showed the best performance, with the correlation coefficient of 0.8935, and the root mean square error of 0.392 in the prediction set. In addition, models based on the spectra information provided better performance than that based on the color parameters. Therefore, the VIS-NIR spectroscopy technique is a promising tool for rapid and accurate evaluation of the sensory quality of black tea samples.

  19. Intelligent evaluation of color sensory quality of black tea by visible-near infrared spectroscopy technology: A comparison of spectra and color data information.

    PubMed

    Ouyang, Qin; Liu, Yan; Chen, Quansheng; Zhang, Zhengzhu; Zhao, Jiewen; Guo, Zhiming; Gu, Hang

    2017-06-05

    Instrumental test of black tea samples instead of human panel test is attracting massive attention recently. This study focused on an investigation of the feasibility for estimation of the color sensory quality of black tea samples using the VIS-NIR spectroscopy technique, comparing the performances of models based on the spectra and color information. In model calibration, the variables were first selected by genetic algorithm (GA); then the nonlinear back propagation-artificial neural network (BPANN) models were established based on the optimal variables. In comparison with the other models, GA-BPANN models from spectra data information showed the best performance, with the correlation coefficient of 0.8935, and the root mean square error of 0.392 in the prediction set. In addition, models based on the spectra information provided better performance than that based on the color parameters. Therefore, the VIS-NIR spectroscopy technique is a promising tool for rapid and accurate evaluation of the sensory quality of black tea samples.

  20. Black Voices

    ERIC Educational Resources Information Center

    McGowan, Jr., Martin J.

    1969-01-01

    "A television show by blacks for blacks--coupled with a program of training for black television technicians--was the basic concept of the Black Voices" series aired over KTCA-TV and KTCI-TV in Minneapolis and St. Paul during the 1968-1969 television season. The series was designed to provide understanding among blacks of the Twin…

  1. 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.

  2. A Sky Chock-Full of Black Holes

    NASA Image and Video Library

    2012-08-29

    With its all-sky infrared survey, NASA Wide-field Infrared Survey Explorer, or WISE, has identified millions of quasar candidates. Quasars are supermassive black holes with masses millions to billions times greater than our sun.

  3. Thermodynamic hardness and the maximum hardness principle

    NASA Astrophysics Data System (ADS)

    Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto

    2017-08-01

    An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T-1(I -A ) , where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.

  4. Thermodynamic hardness and the maximum hardness principle.

    PubMed

    Franco-Pérez, Marco; Gázquez, José L; Ayers, Paul W; Vela, Alberto

    2017-08-21

    An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T(-1)(I-A), where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.

  5. THE VARIABLE NEAR-INFRARED COUNTERPART OF THE MICROQUASAR GRS 1758–258

    SciTech Connect

    Luque-Escamilla, Pedro L.

    2014-12-10

    We present a new study of the microquasar system GRS 1758–258 in the near-infrared domain based on archival observations with the Hubble Space Telescope and the NICMOS camera. In addition to confirming the near-infrared counterpart pointed out by Muñoz-Arjonilla et al., we show that this object displays significant photometric variability. From its average magnitudes, we also find that GRS 1758–258 fits well within the correlation between the optical/near-infrared and X-ray luminosity known to exist for low-mass, black-hole candidate X-ray binaries in a hard state. Moreover, the spectral energy distribution built using all radio, near-infrared, and X-ray data available closest in time to the NICMOS observations can be reasonably interpreted in terms of a self-absorbed radio jet and an irradiated accretion disk model around a stellar-mass black hole. All these facts match the expected behavior of a compact binary system and strengthen our confidence in the counterpart identification.

  6. 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

  7. Black Culture

    ERIC Educational Resources Information Center

    Brown, Angela Khristin

    2013-01-01

    The migration of blacks in North America through slavery became united. The population of blacks passed down a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape…

  8. Black holes.

    PubMed

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

    2001-09-11

    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.

  9. Black Alcoholism.

    ERIC Educational Resources Information Center

    Watts, Thomas D.; Wright, Roosevelt

    1988-01-01

    Examines some aspects of the problem of alcoholism among Blacks, asserting that Black alcoholism can best be considered in an ecological, environmental, sociocultural, and public health context. Notes need for further research on alcoholism among Blacks and for action to reduce the problem of Black alcoholism. (NB)

  10. Graybody Factors and Infrared Divergences

    NASA Astrophysics Data System (ADS)

    Anderson, Paul; Fabbri, Alessandro; Balbinot, Roberto; Parentani, Renaud

    2015-04-01

    A method of computing the gray-body factors for static spherically symmetric and BEC acoustic black holes using a Volterra integral equation is given. The results are used to investigate infrared divergences in the particle number, two-point function, point-split stress-energy tensor and density-density correlation function. Infrared divergences in the particle number and two-point function occur if the gray-body factor approaches a nonzero constant in the zero frequency limit, as happens for Schwarzschild-de Sitter black holes and BEC acoustic black holes. However, no infrared divergences occur in the point-split stress-energy tensor or the density-density correlation function. Supported in part by the National Science Foundation under Grant Nos. PHY-0856050 and PHY-1308325.

  11. Complete multiwavelength evolution of Galactic black hole transients during outburst decay. I. Conditions for 'compact' jet formation

    SciTech Connect

    Kalemci, E.; Dinçer, T.; Chun, Y. Y.; Tomsick, J. A.; Buxton, M. M.; Bailyn, C. D.

    2013-12-20

    Compact, steady jets are observed in the near infrared and radio bands in the hard state of Galactic black hole transients as their luminosity decreases and the source moves toward a quiescent state. Recent radio observations indicate that the jets turn off completely in the soft state; therefore, multiwavelength monitoring of black hole transients is essential to probe the formation of jets. In this work, we conducted a systematic study of all black hole transients with near infrared and radio coverage during their outburst decays. We characterized the timescales of changes in X-ray spectral and temporal properties and also in near infrared and/or in radio emission. We confirmed that state transitions occur in black hole transients at a very similar fraction of their respective Eddington luminosities. We also found that the near infrared flux increase that could be due to the formation of a compact jet is delayed by a time period of days with respect to the formation of a corona. Finally, we found a threshold disk Eddington luminosity fraction for the compact jets to form. We explain these results with a model such that the increase in the near infrared flux corresponds to a transition from a patchy, small-scale height corona along with an optically thin outflow to a large-scale height corona that allows for collimation of a steady compact jet. We discuss the timescale of jet formation in terms of transport of magnetic fields from the outer parts of the disk, and we also consider two alternative explanations for the multiwavelength emission: hot inner accretion flows and irradiation.

  12. Hardness methods for testing maize kernels.

    PubMed

    Fox, Glen; Manley, Marena

    2009-07-08

    Maize is a highly important crop to many countries around the world, through the sale of the maize crop to domestic processors and subsequent production of maize products and also provides a staple food to subsistance farms in undeveloped countries. In many countries, there have been long-term research efforts to develop a suitable hardness method that could assist the maize industry in improving efficiency in processing as well as possibly providing a quality specification for maize growers, which could attract a premium. This paper focuses specifically on hardness and reviews a number of methodologies as well as important biochemical aspects of maize that contribute to maize hardness used internationally. Numerous foods are produced from maize, and hardness has been described as having an impact on food quality. However, the basis of hardness and measurement of hardness are very general and would apply to any use of maize from any country. From the published literature, it would appear that one of the simpler methods used to measure hardness is a grinding step followed by a sieving step, using multiple sieve sizes. This would allow the range in hardness within a sample as well as average particle size and/or coarse/fine ratio to be calculated. Any of these parameters could easily be used as reference values for the development of near-infrared (NIR) spectroscopy calibrations. The development of precise NIR calibrations will provide an excellent tool for breeders, handlers, and processors to deliver specific cultivars in the case of growers and bulk loads in the case of handlers, thereby ensuring the most efficient use of maize by domestic and international processors. This paper also considers previous research describing the biochemical aspects of maize that have been related to maize hardness. Both starch and protein affect hardness, with most research focusing on the storage proteins (zeins). Both the content and composition of the zein fractions affect

  13. Education and Black Struggle: Notes from the Colonized World.

    ERIC Educational Resources Information Center

    Institute of the Black World, Atlanta, GA.

    The contents of this document are organized in six parts, as follows. Part I "IBW and the Vocation of the Black Scholar," includes "The Vocation of the Black Scholar and the Struggles of the Black Community," Vincent Harding. Part II "Colonial Ideology and Colonized Resistance," includes: "African Independence…

  14. Black Contributors to Educational Technology.

    ERIC Educational Resources Information Center

    Greene, John W.; McJulien, Wesley J.

    1987-01-01

    Recognizes and profiles seven outstanding black contributors to the field of educational technology: Harry A. Johnson, Lionel Sebastian Duncan, John W. Greene, Edward O. Minor, Howard A. Myrick, Diane T. Hopkins, Wesley Joseph McJulien, and Louis T. Harding. (LRW)

  15. Black Contributors to Educational Technology.

    ERIC Educational Resources Information Center

    Greene, John W.; McJulien, Wesley J.

    1987-01-01

    Recognizes and profiles seven outstanding black contributors to the field of educational technology: Harry A. Johnson, Lionel Sebastian Duncan, John W. Greene, Edward O. Minor, Howard A. Myrick, Diane T. Hopkins, Wesley Joseph McJulien, and Louis T. Harding. (LRW)

  16. Hard X-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.

    1981-01-01

    Past hard X-ray and lower energy satellite instruments are reviewed and it is shown that observation above 20 keV and up to hundreds of keV can provide much valuable information on the astrophysics of cosmic sources. To calculate possible sensitivities of future arrays, the efficiencies of a one-atmosphere inch gas counter (the HEAO-1 A-2 xenon filled HED3) and a 3 mm phoswich scintillator (the HEAO-1 A-4 Na1 LED1) were compared. Above 15 keV, the scintillator was more efficient. In a similar comparison, the sensitivity of germanium detectors did not differ much from that of the scintillators, except at high energies where the sensitivity would remain flat and not rise with loss of efficiency. Questions to be addressed concerning the physics of active galaxies and the diffuse radiation background, black holes, radio pulsars, X-ray pulsars, and galactic clusters are examined.

  17. Infrared Investigations.

    ERIC Educational Resources Information Center

    Lascours, Jean; Albe, Virginie

    2001-01-01

    Describes a series of simple and nontraditional experiments that enable students to discover the properties of infrared radiation by studying the propagation, reflection, diffusion, and refraction of infrared. The experiments rely on two modules, an infrared transmitter and an infrared receiver. (SAH)

  18. Infrared Investigations.

    ERIC Educational Resources Information Center

    Lascours, Jean; Albe, Virginie

    2001-01-01

    Describes a series of simple and nontraditional experiments that enable students to discover the properties of infrared radiation by studying the propagation, reflection, diffusion, and refraction of infrared. The experiments rely on two modules, an infrared transmitter and an infrared receiver. (SAH)

  19. Discovery and X-ray Monitoring of a New Black Hole Candidate XTE J1752-223

    NASA Astrophysics Data System (ADS)

    Shaposhnikov, Nikolai; Swank, J. H.; Markwardt, C. B.; Krimm, H.

    2010-03-01

    On October 23, 2009 a new X-ray transient source XTE J1752-223 was discovered by RXTE during observations scanning the Galactic Bulge region. Source identification in the optical, infra-red, and radio immediately followed. The first pointed RXTE observation, three days after the discovery, revealed a very hard non-thermal energy spectrum and strong iron line emission. After the initial rise the source flux leveled off and showed very stable properties for more than a month of monitoring observations until the Sun was too close for RXTE to observe. We analyzed RXTE data collected during this monitoring campaign. The aperiodic fast variability properties are strongly reminiscent of the extreme hard states shown by the well known black hole binary Cygnus X-1, as well as several other black hole candidates. The overall similarity of the source properties to those of other Galactic black holes classify XTE J1752-223 as a new stellar black hole candidate. We compare spectral and variability properties of XTE J1752-223 to Cygnus X-1 and discuss possible implications for various mechanisms of non-thermal emission.

  20. Infrared source test

    SciTech Connect

    Ott, L.

    1994-11-15

    The purpose of the Infrared Source Test (IRST) is to demonstrate the ability to track a ground target with an infrared sensor from an airplane. The system is being developed within the Advance Technology Program`s Theater Missile Defense/Unmanned Aerial Vehicle (UAV) section. The IRST payload consists of an Amber Radiance 1 infrared camera system, a computer, a gimbaled mirror, and a hard disk. The processor is a custom R3000 CPU board made by Risq Modular Systems, Inc. for LLNL. The board has ethernet, SCSI, parallel I/O, and serial ports, a DMA channel, a video (frame buffer) interface, and eight MBytes of main memory. The real-time operating system VxWorks has been ported to the processor. The application code is written in C on a host SUN 4 UNIX workstation. The IRST is the result of a combined effort by physicists, electrical and mechanical engineers, and computer scientists.

  1. Ordering of hard particles between hard walls

    NASA Astrophysics Data System (ADS)

    Chrzanowska, A.; Teixeira, P. I. C.; Ehrentraut, H.; Cleaver, D. J.

    2001-05-01

    The structure of a fluid of hard Gaussian overlap particles of elongation κ = 5, confined between two hard walls, has been calculated from density-functional theory and Monte Carlo simulations. By using the exact expression for the excluded volume kernel (Velasco E and Mederos L 1998 J. Chem. Phys. 109 2361) and solving the appropriate Euler-Lagrange equation entirely numerically, we have been able to extend our theoretical predictions into the nematic phase, which had up till now remained relatively unexplored due to the high computational cost. Simulation reveals a rich adsorption behaviour with increasing bulk density, which is described semi-quantitatively by the theory without any adjustable parameters.

  2. Black Art.

    ERIC Educational Resources Information Center

    Baraka, Amiri

    1987-01-01

    Discusses black art as not only an expression of black life but as revolutionary art. It must be collective, functional, and committing. It must also be anti-racist, anti-capitalist, and anti-imperialist. (LHW)

  3. Forensic analysis of black coral (Order Antipatharia).

    PubMed

    Espinoza, Edgard O; Scanlan, Michael D; McClure, Pamela J; Baker, Barry W

    2012-03-10

    Fourier-transform infrared spectroscopy (FTIR), discriminate analysis, X-ray fluorescence spectrometry (XRF), and stereoscopic microscopy were used to separate black coral forensic evidence items from similarly appearing items manufactured from plastics, bovid keratin, and mangrove wood. In addition, novel observations were made of bromine and iodine relationships in black coral that have not been previously reported.

  4. 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…

  5. 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…

  6. 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…

  7. Diamondlike Protective Coats For Infrared Windows

    NASA Technical Reports Server (NTRS)

    Swec, Diane M.; Banks, Bruce A.; Mirtich, Michael J.

    1992-01-01

    Report describes experiments in which four infrared-transparent window materials were coated with diamondlike carbon films. Purpose to investigate ability of films to protect infrared windows against erosion by rain and wind-blown hard particles. Diamondlike films chosen as protective coats because they are transparent over broad spectral range and resist attack by chemicals, moisture, and abrasion. Experiments yield mixed results.

  8. Session: Hard Rock Penetration

    SciTech Connect

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  9. Hardness Tester for Polyur

    NASA Technical Reports Server (NTRS)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  10. Hardness Tester for Polyur

    NASA Technical Reports Server (NTRS)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  11. Black Holes

    NASA Astrophysics Data System (ADS)

    Luminet, Jean-Pierre

    1992-09-01

    Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.

  12. A GENERAL RELATIVISTIC MODEL OF ACCRETION DISKS WITH CORONAE SURROUNDING KERR BLACK HOLES

    SciTech Connect

    You Bei; Cao Xinwu; Yuan Yefei E-mail: cxw@shao.ac.cn

    2012-12-20

    We calculate the structure of a standard accretion disk with a corona surrounding a massive Kerr black hole in the general relativistic frame, in which the corona is assumed to be heated by the reconnection of the strongly buoyant magnetic fields generated in the cold accretion disk. The emergent spectra of accretion disk-corona systems are calculated by using the relativistic ray-tracing method. We propose a new method to calculate the emergent Comptonized spectra from the coronae. The spectra of disk-corona systems with a modified {alpha}-magnetic stress show that both the hard X-ray spectral index and the hard X-ray bolometric correction factor L{sub bol}/L{sub X,2-10keV} increase with the dimensionless mass accretion rate, which is qualitatively consistent with the observations of active galactic nuclei. The fraction of the power dissipated in the corona decreases with increasing black hole spin parameter a, which leads to lower electron temperatures of the coronae for rapidly spinning black holes. The X-ray emission from the coronae surrounding rapidly spinning black holes becomes weak and soft. The ratio of the X-ray luminosity to the optical/UV luminosity increases with the viewing angle, while the spectral shape in the X-ray band is insensitive to the viewing angle. We find that the spectral index in the infrared waveband depends on the mass accretion rate and the black hole spin a, which deviates from the f{sub {nu}}{proportional_to}{nu}{sup 1/3} relation expected by the standard thin disk model.

  13. The hard metal diseases

    SciTech Connect

    Cugell, D.W. )

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.66 references.

  14. The hard metal diseases.

    PubMed

    Cugell, D W

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.

  15. A COMPARISON OF X-RAY AND MID-INFRARED SELECTION OF OBSCURED ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Eckart, Megan E.; Harrison, Fiona A.; McGreer, Ian D.; Helfand, David J.; Stern, Daniel

    2010-01-01

    , unbiased census of supermassive black hole growth and evolution, a combination of sensitive infrared, X-ray, and hard X-ray selection is required. We conclude by discussing what samples will be provided by upcoming survey missions such as WISE, eROSITA, and NuSTAR.

  16. Dynamic hardness of metals

    NASA Astrophysics Data System (ADS)

    Liang, Xuecheng

    Dynamic hardness (Pd) of 22 different pure metals and alloys having a wide range of elastic modulus, static hardness, and crystal structure were measured in a gas pulse system. The indentation contact diameter with an indenting sphere and the radius (r2) of curvature of the indentation were determined by the curve fitting of the indentation profile data. r 2 measured by the profilometer was compared with that calculated from Hertz equation in both dynamic and static conditions. The results indicated that the curvature change due to elastic recovery after unloading is approximately proportional to the parameters predicted by Hertz equation. However, r 2 is less than the radius of indenting sphere in many cases which is contradictory to Hertz analysis. This discrepancy is believed due to the difference between Hertzian and actual stress distributions underneath the indentation. Factors which influence indentation elastic recovery were also discussed. It was found that Tabor dynamic hardness formula always gives a lower value than that directly from dynamic hardness definition DeltaE/V because of errors mainly from Tabor's rebound equation and the assumption that dynamic hardness at the beginning of rebound process (Pr) is equal to kinetic energy change of an impact sphere over the formed crater volume (Pd) in the derivation process for Tabor's dynamic hardness formula. Experimental results also suggested that dynamic to static hardness ratio of a material is primarily determined by its crystal structure and static hardness. The effects of strain rate and temperature rise on this ratio were discussed. A vacuum rotating arm apparatus was built to measure Pd at 70, 127, and 381 mum sphere sizes, these results exhibited that Pd is highly depended on the sphere size due to the strain rate effects. P d was also used to substitute for static hardness to correlate with abrasion and erosion resistance of metals and alloys. The particle size effects observed in erosion were

  17. Organizing Your Hard Disk.

    ERIC Educational Resources Information Center

    Stocker, H. Robert; Hilton, Thomas S. E.

    1991-01-01

    Suggests strategies that make hard disk organization easy and efficient, such as making, changing, and removing directories; grouping files by subject; naming files effectively; backing up efficiently; and using PATH. (JOW)

  18. Organizing Your Hard Disk.

    ERIC Educational Resources Information Center

    Stocker, H. Robert; Hilton, Thomas S. E.

    1991-01-01

    Suggests strategies that make hard disk organization easy and efficient, such as making, changing, and removing directories; grouping files by subject; naming files effectively; backing up efficiently; and using PATH. (JOW)

  19. Radiation from hard objects

    SciTech Connect

    Canavan, G.H.

    1997-02-01

    The inference of the diameter of hard objects is insensitive to radiation efficiency. Deductions of radiation efficiency from observations are very sensitive - possibly overly so. Inferences of the initial velocity and trajectory vary similarly, and hence are comparably sensitive.

  20. Portable infrared reflectometer for evaluating emittance

    NASA Astrophysics Data System (ADS)

    Jaworske, Donald A.; Skowronski, Timothy J.

    2000-01-01

    Optical methods are frequently used to evaluate the emittance of candidate spacecraft thermal control materials. One new optical method utilizes a portable infrared reflectometer capable of obtaining spectral reflectance of an opaque surface in the range of 2 to 25 microns using a Michelson-Type FTIR interferometer. This miniature interferometer collects many infrared spectra over a short period of time. It also allows the size of the instrument to be small such that spectra can be collected in the laboratory or in the field. Infrared spectra are averaged and integrated with respect to the room temperature black body spectrum to yield emittance at 300 K. Integrating with respect to other black body spectra yields emittance values at other temperatures. Absorption bands in the spectra may also be used for chemical species identification. The emittance of several samples was evaluated using this portable infrared reflectometer, an old infrared reflectometer equipped with dual rotating black body cavities, and a bench top thermal vacuum chamber. Samples for evaluation were purposely selected such that a range of emittance values and thermal control material types would be represented, including polished aluminum, Kapton®, silvered Teflon®, and the inorganic paint Z-93-P. Results indicate an excellent linear relationship between the room temperature emittance calculated from infrared spectral data and the emittance obtained from the dual rotating black body cavities and thermal vacuum chamber. The prospect of using the infrared spectral data for chemical species identification will also be discussed. .

  1. INFRARED CLASSIFICATION AND LUMINOSITIES FOR DUSTY ACTIVE GALACTIC NUCLEI AND THE MOST LUMINOUS QUASARS

    SciTech Connect

    Weedman, Daniel; Sargsyan, Lusine; Houck, James; Barry, Donald; Lebouteiller, Vianney

    2012-12-20

    Mid-infrared spectroscopic measurements from the Infrared Spectrometer (IRS) on Spitzer are given for 125 hard X-ray active galactic nuclei (AGNs; 14-195 keV) from the Swift Burst Alert Telescope (BAT) sample and for 32 AGNs with black hole masses (BHMs) from reverberation mapping. The 9.7 {mu}m silicate feature in emission or absorption defines an infrared AGN classification describing whether AGNs are observed through dust clouds, indicating that 55% of the BAT AGNs are observed through dust. The mid-infrared dust continuum luminosity is shown to be an excellent indicator of intrinsic AGN luminosity, scaling closely with the hard X-ray luminosity, log {nu}L{sub {nu}}(7.8 {mu}m)/L(X) = -0.31 {+-} 0.35, and independent of classification determined from silicate emission or absorption. Dust luminosity scales closely with BHM, log {nu}L{sub {nu}}(7.8 {mu}m) = (37.2 {+-} 0.5) + 0.87 log BHM for luminosity in erg s{sup -1} and BHM in M{sub Sun }. The 100 most luminous type 1 quasars as measured in {nu}L{sub {nu}}(7.8 {mu}m) are found by comparing Sloan Digital Sky Survey (SDSS) optically discovered quasars with photometry at 22 {mu}m from the Wide-Field Infrared Survey Explorer (WISE), scaled to rest frame 7.8 {mu}m using an empirical template determined from IRS spectra. The most luminous SDSS/WISE quasars have the same maximum infrared luminosities for all 1.5 < z < 5, reaching total infrared luminosity L{sub IR} = 10{sup 14.4} L{sub Sun }. Comparing with dust-obscured galaxies from Spitzer and WISE surveys, we find no evidence of hyperluminous obscured quasars whose maximum infrared luminosities exceed the maximum infrared luminosities of optically discovered quasars. Bolometric luminosities L{sub bol} estimated from rest-frame optical or ultraviolet luminosities are compared to L{sub IR}. For the local AGN, the median log L{sub IR}/L{sub bol} = -0.35, consistent with a covering factor of 45% for the absorbing dust clouds. For the SDSS/WISE quasars, the median log L

  2. Localized Surface Plasmons in Nanostructured Monolayer Black Phosphorus.

    PubMed

    Liu, Zizhuo; Aydin, Koray

    2016-06-08

    Plasmonic materials provide electric-field localization and light confinement at subwavelength scales due to strong light-matter interaction around resonance frequencies. Graphene has been recently studied as an atomically thin plasmonic material for infrared and terahertz wavelengths. Here, we theoretically investigate localized surface plasmon resonances (LSPR) in a monolayer, nanostructured black phosphorus (BP). Using finite-difference time-domain simulations, we demonstrate LSPRs at mid-infrared and far-infrared wavelength regime in BP nanoribbon and nanopatch arrays. Because of strong anisotropic in-plane properties of black phosphorus emerging from its puckered crystal structure, black phosphorus nanostructures provide polarization dependent, anisotropic plasmonic response. Electromagnetic simulations reveal that monolayer black phosphorus nanostructures can strongly confine infrared radiation in an atomically thin material. Black phosphorus can find use as a highly anisotropic plasmonic devices.

  3. 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…

  4. 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…

  5. Backyard Infrared Trapping

    NASA Astrophysics Data System (ADS)

    Gibbons, Thomas C.

    2014-12-01

    In this time of concern over climate change due to the atmospheric greenhouse effect,1 teachers often choose to extend relevant classroom work by the use of physical models to test statements. Here we describe an activity in which inexpensive backyard models made from cardboard boxes covered with various household transparent materials allow students to explore how transmission of visible and infrared light can affect the temperature.2 Our basic setup is shown schematically in Fig. 1, in which a black-lined box with a thermometer in contact with the bottom is covered with transparent (to visible light) household materials.

  6. The Dynamic Infrared Sky

    NASA Astrophysics Data System (ADS)

    Kasliwal, Mansi M.; SPIRITS (Spitzer InfraRed Intensive Transients Survey) Team

    2017-01-01

    The dynamic infrared sky is hitherto largely unexplored. I will present the SPitzer InfraRed Intensive Transients Survey (SPIRITS) --- a systematic search of 194 nearby galaxies within 30 Mpc, on timescales ranging between a week to a year, to a depth of 20 mag with Spitzer's IRAC camera. SPIRITS has already uncovered over 95 explosive transients and over 1200 strong variables. Of these, 37 infrared transients are especially interesting as they have no optical counterparts whatsoever even with deep limits from Keck and HST. Interpretation of these new discoveries may include (i) the birth of massive binaries that drive shocks in their molecular cloud, (ii) stellar mergers with dusty winds, (iii) 8--10 solar mass stars experiencing e-capture induced collapse in their cores, (iv) enshrouded supernovae, or (v) formation of stellar mass black holes. SPIRITS reveals that the infrared sky is not just as dynamic as the optical sky; it also provides access to unique, elusive signatures in stellar astrophysics.

  7. Softeners for hardness removal.

    PubMed

    Shetty, Rashma; Manjunath, N T; Babu, B T Suresh

    2005-10-01

    The depletion of water resources, both surface and subsurface and deterioration of water quality made researchers and policy makers to think of the possible remedies to make water sources potable / wholesome. There is a need to address the problems of hardness and fluoride in subsurface water on priority basis. In this direction, bench scale studies were conducted to evaluate the performance of water softeners. Indepth studies were carried out at University B.D.T College of Engineering, Davangere, Karnataka, to assess the performance of bench scale softeners of D to H ratio 1:2, 1:3, 1:4 in removing hardness of varied concentrations from both synthetic and natural water samples. Studies revealed that irrespective of D to H ratio of softeners, the waters having hardness concentration up to 1000 mg/l can be treated to the same degree (81.68% and above). The findings of regeneration studies and cost economics are also summarized in this paper.

  8. Enhanced performance of VOx-based bolometer using patterned gold black absorber

    NASA Astrophysics Data System (ADS)

    Smith, Evan M.; Panjwani, Deep; Ginn, James; Warren, Andrew; Long, Christopher; Figuieredo, Pedro; Smith, Christian; Perlstein, Joshua; Walter, Nick; Hirschmugl, Carol; Peale, Robert E.; Shelton, David J.

    2015-06-01

    Patterned highly absorbing gold black film has been selectively deposited on the active surfaces of a vanadium-oxide-based infrared bolometer array. Patterning by metal lift-off relies on protection of the fragile gold black with an evaporated oxide, which preserves gold black's near unity absorption. This patterned gold black also survives the dry-etch removal of the sacrificial polyimide used to fabricate the air-bridge bolometers. Infrared responsivity is substantially improved by the gold black coating without significantly increasing noise. The increase in the time constant caused by the additional mass of gold black is a modest 14%.

  9. Budgeting in Hard Times.

    ERIC Educational Resources Information Center

    Parrino, Frank M.

    2003-01-01

    Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

  10. Budgeting in Hard Times.

    ERIC Educational Resources Information Center

    Parrino, Frank M.

    2003-01-01

    Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

  11. Running in Hard Times

    ERIC Educational Resources Information Center

    Berry, John N., III

    2009-01-01

    Roberta Stevens and Kent Oliver are campaigning hard for the presidency of the American Library Association (ALA). Stevens is outreach projects and partnerships officer at the Library of Congress. Oliver is executive director of the Stark County District Library in Canton, Ohio. They have debated, discussed, and posted web sites, Facebook pages,…

  12. Running in Hard Times

    ERIC Educational Resources Information Center

    Berry, John N., III

    2009-01-01

    Roberta Stevens and Kent Oliver are campaigning hard for the presidency of the American Library Association (ALA). Stevens is outreach projects and partnerships officer at the Library of Congress. Oliver is executive director of the Stark County District Library in Canton, Ohio. They have debated, discussed, and posted web sites, Facebook pages,…

  13. CSI: Hard Drive

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2008-01-01

    Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

  14. Black tea

    MedlinePlus

    ... But this does not seem to occur in humans.Flutamide (Eulexin)The body breaks down flutamide (Eulexin) ... much medicine the body absorbs. To avoid this interaction, avoid black tea 1 hour before and 2 ...

  15. Connections Between Jet Formation and Multiwavelength Spectral Evolution in Black Hole Transients

    NASA Technical Reports Server (NTRS)

    Kakemci, Emrah; Chun, Yoon-Young; Dincer, Tolga; Buxton, Michelle; Tomsick, John A.; Corbel, Stephane; Kaaret, Philip

    2011-01-01

    Multiwavelength observations are the key to understand conditions of jet formation in Galactic black hole transient (GBHT) systems. By studying radio and optical-infrared evolution of such systems during outburst decays, the compact jet formation can be traced. Comparing this with X-ray spectral and timing evolution we can obtain physical and geometrical conditions for jet formation, and study the contribution of jets to X-ray emission. In this work, first X-ray evolution - jet relation for XTE J1752-223 will be discussed. This source had very good coverage in X-rays, optical, infrared and radio. A long exposure with INTEGRAL also allowed us to study gamma-ray behavior after the jet turns on. We will also show results from the analysis of data from GX 339-4 in the hard state with SUZAKU at low flux levels. The fits to iron line fluorescence emission show that the inner disk radius increases by a factor of greater than 27 with respect to radii in bright states. This result, along with other disk radius measurements in the hard state will be discussed within the context of conditions for launching and sustaining jets.

  16. Connections between jet formation and multiwavelength spectral evolution in black hole transients

    NASA Astrophysics Data System (ADS)

    Kalemci, Emrah; Chun, Yoon-Young; Dinçer, Tolga; Buxton, Michelle; Tomsick, John A.; Corbel, Stephane; Kaaret, Philip

    2011-02-01

    Multiwavelength observations are the key to understand conditions of jet formation in Galactic black hole transient (GBHT) systems. By studying radio and optical-infrared evolution of such systems during outburst decays, the compact jet formation can be traced. Comparing this with X-ray spectral and timing evolution we can obtain physical and geometrical conditions for jet formation, and study the contribution of jets to X-ray emission. In this work, first X-ray evolution - jet relation for XTE J1752-223 will be discussed. This source had very good coverage in X-rays, optical, infrared and radio. A long exposure with INTEGRAL also allowed us to study gamma-ray behavior after the jet turns on. We will also show results from the analysis of data from GX 339-4 in the hard state with SUZAKU at low flux levels. The fits to iron line fluorescence emission show that the inner disk radius increases by a factor of >27 with respect to radii in bright states. This result, along with other disk radius measurements in the hard state will be discussed within the context of conditions for launching and sustaining jets.

  17. Connections Between Jet Formation and Multiwavelength Spectral Evolution in Black Hole Transients

    NASA Technical Reports Server (NTRS)

    Kakemci, Emrah; Chun, Yoon-Young; Dincer, Tolga; Buxton, Michelle; Tomsick, John A.; Corbel, Stephane; Kaaret, Philip

    2011-01-01

    Multiwavelength observations are the key to understand conditions of jet formation in Galactic black hole transient (GBHT) systems. By studying radio and optical-infrared evolution of such systems during outburst decays, the compact jet formation can be traced. Comparing this with X-ray spectral and timing evolution we can obtain physical and geometrical conditions for jet formation, and study the contribution of jets to X-ray emission. In this work, first X-ray evolution - jet relation for XTE J1752-223 will be discussed. This source had very good coverage in X-rays, optical, infrared and radio. A long exposure with INTEGRAL also allowed us to study gamma-ray behavior after the jet turns on. We will also show results from the analysis of data from GX 339-4 in the hard state with SUZAKU at low flux levels. The fits to iron line fluorescence emission show that the inner disk radius increases by a factor of greater than 27 with respect to radii in bright states. This result, along with other disk radius measurements in the hard state will be discussed within the context of conditions for launching and sustaining jets.

  18. X-RAY, OPTICAL, AND INFRARED OBSERVATIONS OF GX 339-4 DURING ITS 2011 DECAY

    SciTech Connect

    Dincer, Tolga; Kalemci, Emrah; Buxton, Michelle M.; Bailyn, Charles D.; Tomsick, John A.; Corbel, Stephane

    2012-07-01

    We report multiwavelength observations of the black hole transient GX 339-4 during its outburst decay in 2011 using the data from RXTE, Swift, and SMARTS. Based on the X-ray spectral, temporal, and optical and infrared (OIR) properties, the source evolved from the soft intermediate to the hard state. Twelve days after the start of the transition toward the hard state, a rebrightening was observed simultaneously in the optical and the infrared bands. Spectral energy distributions (SEDs) were created from observations at the start, and close to the peak of the rebrightening. The excess OIR emission above the smooth exponential decay yields flat spectral slopes for these SEDs. Assuming that the excess is from a compact jet, we discuss the possible locations of the spectral break that mark the transition from optically thick to optically thin synchrotron components. Only during the rising part of the rebrightening, we detected fluctuations with the binary period of the system. We discuss a scenario that includes irradiation of the disk in the intermediate state, irradiation of the secondary star during OIR rise, and jet emission dominating during the peak to explain the entire evolution of the OIR light curve.

  19. Psychosocial Correlates of Alcohol Consumption among Black College Students.

    ERIC Educational Resources Information Center

    Ford, Denyce S.; Carr, Peggy G.

    1990-01-01

    Examined impact of psychosocial variables on drinking among 505 Black college students. Lack of social support was best predictor of drinking of hard alcoholic beverages among Black college males. Respondents who began drinking at younger age, had parents who approved of drinking, and had friends who drank were more likely to drink light and hard…

  20. Modeling Manhood: Reimagining Black Male Identities in School

    ERIC Educational Resources Information Center

    Givens, Jarvis R.; Nasir, Na'ilah; ross, kihana; de Royston, Maxine McKinney

    2016-01-01

    This paper examines the process by which stereotypical mainstream representations of black males (as hard, as anti-school, and as disconnected from the domestic sphere) were reimagined in all-black, all-male manhood development classes for 9th graders in urban public high schools. Findings show that instructors debunked stereotypes and created new…

  1. Psychosocial Correlates of Alcohol Consumption among Black College Students.

    ERIC Educational Resources Information Center

    Ford, Denyce S.; Carr, Peggy G.

    1990-01-01

    Examined impact of psychosocial variables on drinking among 505 Black college students. Lack of social support was best predictor of drinking of hard alcoholic beverages among Black college males. Respondents who began drinking at younger age, had parents who approved of drinking, and had friends who drank were more likely to drink light and hard…

  2. Modeling Manhood: Reimagining Black Male Identities in School

    ERIC Educational Resources Information Center

    Givens, Jarvis R.; Nasir, Na'ilah; ross, kihana; de Royston, Maxine McKinney

    2016-01-01

    This paper examines the process by which stereotypical mainstream representations of black males (as hard, as anti-school, and as disconnected from the domestic sphere) were reimagined in all-black, all-male manhood development classes for 9th graders in urban public high schools. Findings show that instructors debunked stereotypes and created new…

  3. Slender Galaxy with Robust Black Hole

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This plot of data from NASA's Spitzer Space Telescope indicates that a flat, spiral galaxy called NGC 3621 has a feeding, supermassive black hole lurking within it -- a surprise considering that astronomers thought this particular class of super-thin galaxies lacked big black holes.

    The data were captured by Spitzer's infrared spectrograph, an instrument that cracks infrared light open to reveal the signatures of elements. In this case, the data, or spectrum, for NGC 3621, shows the signature of highly ionized neon -- a sure sign of an active, supermassive black hole. Only a black hole that is actively consuming gas and stars has enough energy to ionize neon to this state. The other features in this plot are polycyclic aromatic hydrocarbons and chlorine, produced in the gas surrounding stars.

    The results challenge current theories, which hold that supermassive black holes require the bulbous central bulges that poke out from many spiral galaxies to form and grow. NGC 3621 is the second disk galaxy without any bulge found to harbor a supermassive black hole; the first, found in 2003, is NGC 4395. Astronomers have also used Spitzer to find six other mega black holes in thin spirals with only minimal bulges. Together, the findings indicate that, for a galaxy, being plump in the middle is not a necessary condition for growing a rotund black hole.

  4. Slender Galaxy with Robust Black Hole

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This plot of data from NASA's Spitzer Space Telescope indicates that a flat, spiral galaxy called NGC 3621 has a feeding, supermassive black hole lurking within it -- a surprise considering that astronomers thought this particular class of super-thin galaxies lacked big black holes.

    The data were captured by Spitzer's infrared spectrograph, an instrument that cracks infrared light open to reveal the signatures of elements. In this case, the data, or spectrum, for NGC 3621, shows the signature of highly ionized neon -- a sure sign of an active, supermassive black hole. Only a black hole that is actively consuming gas and stars has enough energy to ionize neon to this state. The other features in this plot are polycyclic aromatic hydrocarbons and chlorine, produced in the gas surrounding stars.

    The results challenge current theories, which hold that supermassive black holes require the bulbous central bulges that poke out from many spiral galaxies to form and grow. NGC 3621 is the second disk galaxy without any bulge found to harbor a supermassive black hole; the first, found in 2003, is NGC 4395. Astronomers have also used Spitzer to find six other mega black holes in thin spirals with only minimal bulges. Together, the findings indicate that, for a galaxy, being plump in the middle is not a necessary condition for growing a rotund black hole.

  5. Edge plasmons in monolayer black phosphorus

    NASA Astrophysics Data System (ADS)

    Bao, Zhi-Wei; Wu, Hong-Wei; Zhou, Yu

    2016-12-01

    In this paper, we numerically investigate the edge plasmons in monolayer black phosphorus. It is found that the complex effective indexes of these modes depend on the molecular configuration of the edge. We have calculated the ratio of the real over the imaginary part of the mode effective index, and the results indicate that such edge modes indeed possess outstanding propagation performances in the mid-infrared. In the case of black phosphorus nanoribbon, it seems that only the anti-symmetric modes have low losses, and may be of use in applications. Compared with those at the edge of monolayer black phosphorus, the propagation performances can be further enhanced due to the mode coupling between the two edges. In the end, the effects of substrates are discussed. Our study shows that monolayer black phosphorus may be regarded as a promising candidate for plasmonic applications in the mid-infrared.

  6. Hairy Black Holes in Theories with Massive Gravitons

    NASA Astrophysics Data System (ADS)

    Volkov, Mikhail S.

    This is a brief survey of the known black hole solutions in the theories of ghost-free bigravity and massive gravity. Various black holes exist in these theories, in particular those supporting a massive graviton hair. However, it seems that solutions which could be astrophysically relevant are the same as in General Relativity, or very close to them. Therefore, the no-hair conjecture essentially applies, and so it would be hard to detect the graviton mass by observing black holes.

  7. [Creative work of Greene Vardiman Black].

    PubMed

    Ilić, Dragan V; Zagradjanin, Danica

    2011-01-01

    Over hundred years has elapsed since the publication of "Operative Dentistry" (1908), a book by the famous odontologist and scientist Greene Vardiman Black. Throughout all his life Black worked hard on education, research, lecturing, publishing and teaching others. The innovator in many fields of dental medicine, particularly conservative therapy, he patented numerous inventions, implemented the standardization of instruments and procedures, constructed stomatological drills, gnathodynamometer, material hardness testing moulds, micrometer and microtome. Black is the author of more than 500 articles and innovations, as well as several exceptional books that are considered as classic within the domain of the dental literature, and which many generations were educated on. One can certainly say that Black occupies the honorary position among the eminent personalities of dental scientist as one of the founders of contemporary stomatology. If we take into consideration Black as to his merits in operative dentistry and wider, it could be confirmed that the epoch of contemporary dentistry could be divided into the era before Black, when many dental procedures were performed without scientific foundation, the time during Black when many dilemmas were resolved in operative dentistry branches backed up by laboratory investigations, and finally the homage period of the 20th century when the application of his postulates, instruments and conclusions were gradually being abandoned giving way to modern doctrines and materials due to the rapid advancement of industry of dental materials and operative techniques in modern stomatology all of which should be credited to the development of basic sciences.

  8. Infrared Measurement

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A Jet Propulsion Laboratory Technical Support Package (TSP) describing a technique for processing data from an infrared radiometer assisted a manufacturer of laminates for printed circuit boards. To reduce emissions and lower the cost of producing prepreg (a continuous glass cloth, or web, impregnated with epoxy resin and partially cured by applying heat), Norplex Oak switched to infrared treating towers. The TSP confirmed the company's computer prediction of heat flux patterns, provided information that allowed the company to modify infrared treaters for consistency, and furnished a basis for development of optimal heater placements. The treaters are now successfully operating at increased speeds with improved product consistency.

  9. Unemployment: Hard-Core or Hard-Shell?

    ERIC Educational Resources Information Center

    Lauer, Robert H.

    1972-01-01

    The term hard-core'' makes the unemployed culpable; the term hard shell'' shifts the burden to the employer, and the evidence from the suburban plant indicates that a substantial part of the problem must lie there. (DM)

  10. Super-Hard Superconductivity

    NASA Astrophysics Data System (ADS)

    Adams, Philip; Prozorov, Ruslan

    2005-03-01

    We present the magnetic response of Type-II superconductivity in the extreme pinning limit, where screening currents within an order of magnitude of the Ginzburg-Landau depairing critical current density develop upon the application of a magnetic field. We show that this ``super-hard'' limit is well approximated in highly disordered, cold drawn, Nb wire whose magnetization response is characterized by a cascade of Meissner-like phases, each terminated by a catastrophic collapse of the magnetization. Direct magneto-optic measurements of the flux penetration depth in the virgin magnetization branch are in excellent agreement with the exponential model in which Jc(B)=Jco(-B/Bo), where Jco˜5x10^6 A/cm^2 for Nb. The implications for the fundamental limiting hardness of a superconductor will be discussed.

  11. Multiwavelength Observations of the Black Hole Candidate XTE J1550-564 during the 2000 Outburst

    NASA Astrophysics Data System (ADS)

    Jain, Raj K.; Bailyn, Charles D.; Orosz, Jerome A.; McClintock, Jeffrey E.; Remillard, Ronald A.

    2001-06-01

    We report optical, infrared, and X-ray light curves for the outburst, in 2000, of the black hole candidate XTE J1550-564. We find that the start of the outburst in the H and V bands precedes that seen in the Rossi X-Ray Timing Explorer All-Sky Monitor by 11.5+/-0.9 and 8.8+/-0.6 days, respectively; a similar delay has been observed in two other systems. About 50 days after the primary maxima in the VIH light curves, we find secondary maxima, most prominently in H. This secondary peak is absent in the X-ray light curve but coincides with a transition to the low/hard state. We suggest that this secondary peak may be due to nonthermal emission associated with the formation of a jet.

  12. Life under a black sun

    NASA Astrophysics Data System (ADS)

    Opatrný, Tomáš; Richterek, Lukáš; Bakala, Pavel

    2017-01-01

    Life is dependent on the income of energy with low entropy and the disposal of energy with high entropy. On Earth, the low-entropy energy is provided by solar radiation and the high-entropy energy is disposed of as infrared radiation emitted into cold space. Here, we turn the situation around and imagine the cosmic background radiation as the low-entropy source of energy for a planet orbiting a black hole into which the high-entropy energy is expelled. We estimate the power that can be produced by thermodynamic processes on such a planet, with a particular interest in planets orbiting a fast rotating Kerr black hole as in the science fiction movie Interstellar. We also briefly discuss a reverse Dyson sphere absorbing cosmic background radiation from the outside and dumping waste energy to a black hole inside.

  13. The Sexual Stereotype of the Black Male.

    ERIC Educational Resources Information Center

    Davis, Gary L.; Cross, Herbert J.

    This paper presents the results of a study to examine the existence of sexual stereotyping of black males by white college students. Subjects were 180 male and 180 female white undergraduates; they were tested in sexually segregated groups. Each read one of three types of pornographic stories (hard-core, erotic realism, or sexual fantasy). The…

  14. Harvard, Harvard: He's Perfect and He's Black.

    ERIC Educational Resources Information Center

    Barrett, Paul M.

    1999-01-01

    Describes the higher educational experiences of Lawrence Mungin, an African American who attended Harvard University and Harvard Law School. Mungin believed that working hard and being the good Black would lead to success in the White world. Despite his credentials, he was given trivial work at the law firm that hired him and that he later sued.…

  15. The Sexual Stereotype of the Black Male.

    ERIC Educational Resources Information Center

    Davis, Gary L.; Cross, Herbert J.

    This paper presents the results of a study to examine the existence of sexual stereotyping of black males by white college students. Subjects were 180 male and 180 female white undergraduates; they were tested in sexually segregated groups. Each read one of three types of pornographic stories (hard-core, erotic realism, or sexual fantasy). The…

  16. Broadband Correlations Provide Evidence for Synchrotron Self-Compton X-rays from the Black Hole Binary GX 339-4

    SciTech Connect

    Coriat, M.; Corbel, S.; Buxton, M. M.; Baylin, C. D.

    2009-05-11

    GX 339-4 has been one of the key sources for unravelling the accretion ejection coupling in accreting stellar mass black holes. After a long period of quiescence between 1999 and 2002, GX 339-4 underwent a series of 4 outbursts that have been intensively observed by many ground based observatories (radio/infrared/optical) and satellites (X-rays). Here, we present some specific results of these broad band observational campaigns, focusing on the optical-infrared/X-ray flux correlations over the four outbursts. Thanks to our extensive data-set, we found a strong OIR/X-ray correlation over four decades with the presence of a break in the correlation index. These results seem to favour a synchrotron self-Compton origin for the X-ray emission in GX 339-4 during the hard state and could also provide an indirect detection of the break frequency in the synchrotron spectrum of the compact jets.

  17. Why Infrared?

    ERIC Educational Resources Information Center

    Harris, J. R.

    1973-01-01

    Discusses applications of techniques developed for the remote sensing of infrared radiation. In addition to military applications, remote sensing has become important in collecting environmental data and detecting ecological problems. (JR)

  18. Why Infrared?

    ERIC Educational Resources Information Center

    Harris, J. R.

    1973-01-01

    Discusses applications of techniques developed for the remote sensing of infrared radiation. In addition to military applications, remote sensing has become important in collecting environmental data and detecting ecological problems. (JR)

  19. Periodically kicked hard oscillators.

    PubMed

    Cecchi, G. A.; Gonzalez, D. L.; Magnasco, M. O.; Mindlin, G. B.; Piro, O.; Santillan, A. J.

    1993-01-01

    A model of a hard oscillator with analytic solution is presented. Its behavior under periodic kicking, for which a closed form stroboscopic map can be obtained, is studied. It is shown that the general structure of such an oscillator includes four distinct regions; the outer two regions correspond to very small or very large amplitude of the external force and match the corresponding regions in soft oscillators (invertible degree one and degree zero circle maps, respectively). There are two new regions for intermediate amplitude of the forcing. Region 3 corresponds to moderate high forcing, and is intrinsic to hard oscillators; it is characterized by discontinuous circle maps with a flat segment. Region 2 (low moderate forcing) has a certain resemblance to a similar region in soft oscillators (noninvertible degree one circle maps); however, the limit set of the dynamics in this region is not a circle, but a branched manifold, obtained as the tangent union of a circle and an interval; the topological structure of this object is generated by the finite size of the repelling set, and is therefore also intrinsic to hard oscillators.

  20. SUPER HARD SURFACED POLYMERS

    SciTech Connect

    Mansur, Louis K; Bhattacharya, R; Blau, Peter Julian; Clemons, Art; Eberle, Cliff; Evans, H B; Janke, Christopher James; Jolly, Brian C; Lee, E H; Leonard, Keith J; Trejo, Rosa M; Rivard, John D

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  1. Infrared astronomy

    SciTech Connect

    Neugebauer, G.; Soifer, B.T.; Matthews, K.

    1981-03-01

    Several observational programs in infrared astronomy are described and significant findings are briefly discussed. The near infrared work concentrates largely on the use of the 5 m Hale telescope in spectroscopic and photometric studies of extragalactic sources. Observations of the P alpha line profile in a low redshift quasar, X-ray bursters, reflection nebula, and cataclysmic variables are included. Millimeter continuum observations of dust emission from quasars and galactic molecular clouds are also discussed. Finally, improvements to instrumentation are reported.

  2. Staking Tool for Hard Metals

    NASA Technical Reports Server (NTRS)

    Stein, J. A.

    1982-01-01

    Simple tool stakes hard-steel parts--that is, forces one part into recess on another, deforming receiving part so that it restrains inserted one. Tool allows small machine shops to stake hard steel without massive presses. Can be used, for example, to insert ball and spring into hard steel snap-tool body such as that used to turn socket wrenches. Use is not limited to hard steel; can be used as well to assemble parts made of softer materials.

  3. Investigation of fluids as filling of a biomimetic infrared sensor based on the infrared receptors of pyrophilous insects

    NASA Astrophysics Data System (ADS)

    Kahl, T.; Li, N.; Schmitz, H.; Bousack, H.

    2012-04-01

    The beetle Melanophila acuminata is highly dependent on forest fires. The burned wood serves as food for the larvae and the adults copulate on the burned areas to put their eggs in the freshly burned trees. To be able to detect forest fires from great distances the beetle developed a highly sensitive infrared receptor which works according to a photomechanical principle. The beetle has two pit organs, one on each lateral side, of which each houses around 70 dome shaped infrared receptors. These IR-receptors consist of a hard outer cuticular shell and an inner microfluidic core. When IR-radiation is absorbed, the pressure in the core increases due to the thermal expansion. This results in a deflection of a dendritic tip of a mechanosensitiv neuron which generates the signal. This biological principle was transferred into a new kind of un-cooled technical infrared receptor. To demonstrate the functional principle and the feasibility of this IR-sensor a macroscopic demonstrator sensor was build. It consisted of an inner fluid filled cavity (pressure chamber), an IR-transmissive window and a membrane. The deflection of the membrane due to the absorbed IR-energy was measured by a sensitive commercial capacitive sensor. In the experiments ethanol with added black ink, a mix of ethanol and glucose with additional absorber, air with additional absorber and water were used as fillings of the cavity and compared against each other. In order to get insights into the physics of the results of the experiments accompanying simulations using FEM methods and analytical calculations have been performed. The results showed that ethanol and air as fillings of the cavity caused the largest deflection of the membrane. Furthermore it turned out that the thermal expansion of the sensor housing material has an important influence. The comparison of the measured deflection with calculated deflections showed a good concordance.

  4. The Black Books Roundup.

    ERIC Educational Resources Information Center

    Black Scholar, 1982

    1982-01-01

    Lists "Black and Black related" books available from American and some British publishing companies. Also provides lists of publishers and bookstores that carry works relevant to Blacks and Black studies. (GC)

  5. Unveiling early black holes with JWST

    NASA Astrophysics Data System (ADS)

    Natarajan, Priyamvada

    The formation of direct collapse black hole seeds with masses ~104 - 105 ~M⊙ could help explain the assembly of supermassive black holes powering high redshift quasars. Conditions conducive to the formation of these massive initial seeds exist at high redshift. Halos hosting these massive seeds merge promptly with a nearby galaxy. These early stage mergers at high redshift produce a new class of transient galaxies that contain an accreting black hole that is over-massive compared to the newly acquired stellar component - Obese Black hole Galaxies (OBGs). During this phase, the accretion luminosity of the direct collapse black hole seed exceeds that of the acquired stellar component. Here we calculate the multi-wavelength spectrum of this short-lived OBG stage, and show that there exist unique observational signatures in long wavelengths spanning near, mid to far-infrared that should be detectable by instruments aboard the upcoming James Webb Space Telescope (JWST).

  6. Obituary: Harding Eugene (Gene) Smith, Jr., 1947-2007

    NASA Astrophysics Data System (ADS)

    Lonsdale, Carol; Soifer, Tom

    2009-01-01

    Harding Eugene Smith Junior, or Gene, as he was known to family, friends, and colleagues, passed away after an automobile accident in Encinitas, California, on 16 August 2007. He was 60 years old. Gene had recently retired from UCSD after thirty years of service. A memorial service was held at Quail Botanical Gardens in Encinitas, California, on 23 August 2007. A web page is dedicated to his memory at http://harding.smith.muchloved.com, where contributions of memories are invited. Gene was born in San Jose, California in 1947, to Harding Eugene Smith Senior, and Bernice Smith (nee Smith). Harding Smith Senior was an air-force navigator; therefore Gene spent his childhood moving from one air-force base to another. Although an only child, Gene was very close to his cousin Meg, whom he lived nearby to in Gilroy for a time, and the two were like brother and sister. The elder Harding Smith was lost in action over Cambodia in the mid-sixties. Gene was a dedicated student, a boy scout, and a Presidential Scholar. He majored in Physics at Caltech, where he also took a lively interest in the football team and the Glee Club, and was elected a House Officer. To his close friends, he was known at Caltech as Smitty, and the closest of them was Rob Drew, who gave a glimpse into that period of Gene's life at the memorial: "Gene arrived early at campus his first year, in response to an invitation to join the football team. Gene's size and features reminded the head coach of a long-forgotten player named 'Johnson.' After a few days of confusion, Gene simply replaced the name on his helmet. 'Johnson!' coach would yell, 'get in there!' If Johnson was going to get to play, Gene was going to be the best Johnson available!" Gene spent the summer of 1966 working at Kitt Peak, where his lifetime love of observing with ground-based telescopes began, though he learned some things the hard way, such as the fact that trying to squeeze 40,000 numbers onto a computer that stored only 32

  7. Hard metal composition

    DOEpatents

    Sheinberg, Haskell

    1986-01-01

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 weight percent boron carbide and the remainder a metal mixture comprising from 70 to 90 percent tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 to 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  8. Hard metal composition

    DOEpatents

    Sheinberg, H.

    1983-07-26

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 wt % boron carbide and the remainder a metal mixture comprising from 70 to 90% tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 and 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  9. 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…

  10. 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…

  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. 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…

  13. Black Willow

    Treesearch

    R. M. Krinard

    1980-01-01

    Black willow and other species of Salix together comprise a majority of the stocking. Cottonwood is the chief associate, particularly in the early stages, but green ash, sycamore, pecan, persimmon, waterlocust, American elm, baldcypress, red maple, sugarberry, box-elder, and in some areas, silver maple are invaders preceding the next successional stage.

  14. 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 ...

  15. Prediction of kernel density of corn using single-kernel near infrared spectroscopy

    USDA-ARS?s Scientific Manuscript database

    Corn hardness as is an important property for dry and wet-millers, food processors and corn breeders developing hybrids for specific markets. Of the several methods used to measure hardness, kernel density measurements are one of the more repeatable methods to quantify hardness. Near infrared spec...

  16. Orthognathic surgery norms for American black patients.

    PubMed

    Connor, A M; Moshiri, F

    1985-02-01

    Upon analyzing the literature, it becomes apparent that the hard- and soft-tissue norms of blacks differ from those of whites. However, these established black norms are not complete when evaluating potential surgical cases. Therefore, the intent of this study was to establish black norms that will be valuable aids for diagnosis in such cases. Lateral cephalometric radiographs were taken of 50 white adults (25 male, 25 female) and 50 black North American adults (25 male, 25 female). All subjects met the following criteria: 18 to 50 years of age; a normal Class I skeletal and dental relationship without any severe anteroposterior, vertical, or transverse discrepancies; and a balanced profile. The tracings involved 24 measurements that were analyzed with a digitizer. Sexual differentiation was included within each measurement. Significant differences between white and black subjects were found in the following areas: hard tissue (SNA, ANB, mandibular length, and the Wits analysis); dental (anterior dental height [ADH], amount of tooth exposure at rest, upper incisor-palatal plane [UI-PP], and lower incisor-mandibular plane [LI-MP]); and soft tissue (nasolabial angle [NLA], upper lip length [ULL], lower lip length [LLL], throat length [TL], and the lip-chin-throat angle [LCTA]). From a practical point of view, this study can be used by orthodontists and oral surgeons to aid in the diagnosis of black patients contemplating orthognathic surgery.

  17. Revisiting the definition of local hardness and hardness kernel.

    PubMed

    Polanco-Ramírez, Carlos A; Franco-Pérez, Marco; Carmona-Espíndola, Javier; Gázquez, José L; Ayers, Paul W

    2017-05-17

    An analysis of the hardness kernel and local hardness is performed to propose new definitions for these quantities that follow a similar pattern to the one that characterizes the quantities associated with softness, that is, we have derived new definitions for which the integral of the hardness kernel over the whole space of one of the variables leads to local hardness, and the integral of local hardness over the whole space leads to global hardness. A basic aspect of the present approach is that global hardness keeps its identity as the second derivative of energy with respect to the number of electrons. Local hardness thus obtained depends on the first and second derivatives of energy and electron density with respect to the number of electrons. When these derivatives are approximated by a smooth quadratic interpolation of energy, the expression for local hardness reduces to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba. However, when one combines the first directional derivatives with smooth second derivatives one finds additional terms that allow one to differentiate local hardness for electrophilic attack from the one for nucleophilic attack. Numerical results related to electrophilic attacks on substituted pyridines, substituted benzenes and substituted ethenes are presented to show the overall performance of the new definition.

  18. Infrared Camera

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A sensitive infrared camera that observes the blazing plumes from the Space Shuttle or expendable rocket lift-offs is capable of scanning for fires, monitoring the environment and providing medical imaging. The hand-held camera uses highly sensitive arrays in infrared photodetectors known as quantum well infrared photo detectors (QWIPS). QWIPS were developed by the Jet Propulsion Laboratory's Center for Space Microelectronics Technology in partnership with Amber, a Raytheon company. In October 1996, QWIP detectors pointed out hot spots of the destructive fires speeding through Malibu, California. Night vision, early warning systems, navigation, flight control systems, weather monitoring, security and surveillance are among the duties for which the camera is suited. Medical applications are also expected.

  19. Hard Metal Disease

    PubMed Central

    Bech, A. O.; Kipling, M. D.; Heather, J. C.

    1962-01-01

    In Great Britain there have been no published reports of respiratory disease occurring amongst workers in the hard metal (tungsten carbide) industry. In this paper the clinical and radiological findings in six cases and the pathological findings in one are described. In two cases physiological studies indicated mild alveolar diffusion defects. Histological examination in a fatal case revealed diffuse pulmonary interstitial fibrosis with marked peribronchial and perivascular fibrosis and bronchial epithelial hyperplasia and metaplasia. Radiological surveys revealed the sporadic occurrence and low incidence of the disease. The alterations in respiratory mechanics which occurred in two workers following a day's exposure to dust are described. Airborne dust concentrations are given. The industrial process is outlined and the literature is reviewed. The toxicity of the metals is discussed, and our findings are compared with those reported from Europe and the United States. We are of the opinion that the changes which we would describe as hard metal disease are caused by the inhalation of dust at work and that the component responsible may be cobalt. Images PMID:13970036

  20. Infrared and Raman investigation of rare-earth phosphate glasses for potential use as radioactive waste forms. Historically Black Colleges and Universities Radioactive Waste Management Research Program: Final technical report

    SciTech Connect

    Morgan, S.

    1986-11-10

    This project was designed to investigate the properties of the rare-earth phosphate glasses CeO{sub 2}-P{sub 2}O{sub 5} and Pr{sub 2}O{sub 3}-P{sub 2}O{sub 5} for potential use as radioactive waste glasses. The research involved determination of the glass-forming region, loading capacity, and optimum processing parameters of the glasses. Structural studies of the unloaded host glasses and glasses loaded with simulated waste elements were to be done using Raman, infrared and infrared reflection spectroscopy. Leach testing and spectroscopic studies of the corroded surfaces were also to be performed.

  1. Infrared Thermometer

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Diatek Corporation, San Diego, CA and the Jet Propulsion Lab developed the Diatek Model 7000 aural thermometer which weighs only eight ounces, and measures temperature in less than two seconds using infrared astronomy technology to measure the amount of infrared energy emitted by the eardrum (the same way temperature of stars and planets is measured). This method avoids contact with mucous membranes, virtually eliminating the possibility of cross infection, and permits temperature measurement of newborn, critically ill, or incapacitated patients. Diatek Corporation was purchased by Welch Allyn Inc. The Diatek Model 7000 is now marketed as SureTemp.

  2. Infrared astronomy

    NASA Technical Reports Server (NTRS)

    Gillett, Frederick; Houck, James; Bally, John; Becklin, Eric; Brown, Robert Hamilton; Draine, Bruce; Frogel, Jay; Gatley, Ian; Gehrz, Robert; Hildebrand, Roger

    1991-01-01

    The decade of 1990's presents an opportunity to address fundamental astrophysical issues through observations at IR wavelengths made possible by technological and scientific advances during the last decade. The major elements of recommended program are: the Space Infrared Telescope Facility (SIRTF), the Stratospheric Observatory For Infrared Astronomy (SOFIA) and the IR Optimized 8-m Telescope (IRO), a detector and instrumentation program, the SubMilliMeter Mission (SMMM), the 2 Microns All Sky Survey (2MASS), a sound infrastructure, and technology development programs. Also presented are: perspective, science opportunities, technical overview, project recommendations, future directions, and infrastructure.

  3. Infrared Images

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Earth objects emit natural radiation invisible to the unaided human eye, but visible to infrared scanning devices such as the device developed by Inframetrics, Inc. Such devices serve a number of purposes ranging from detection of heat loss in buildings for energy conservation measures, to examining heat output of industrial machinery for trouble shooting and preventive maintenance. Representative of system is Model 525, a small, lightweight field instrument that scans infrared radiation and translates its findings to a TV picture of the temperature pattern in the scene being viewed. An accessory device permits viewing the thermal radiation in color.

  4. Exposing Black Holes Disguised in Dust

    NASA Image and Video Library

    2012-08-29

    This zoomed-in view of a portion of the all-sky survey from NASA Wide-field Infrared Survey Explorer shows a collection of quasar candidates shown in yellow circles. Quasars are supermassive black holes feeding off gas and dust.

  5. Black Talk and Black Education

    ERIC Educational Resources Information Center

    Abrahams, Roger D.

    1969-01-01

    Demonstrates the need for cultural relativity in avoiding stereotyped reactions to the language of the lower-class black child. Appears in "The Florida FL Reporter special anthology issue, "Linguistic-Cultural Differences and American Education. The central portion of this essay is part of the opening argument of the author's forthcoming book…

  6. 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…

  7. 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…

  8. Survey Of Infrared-Absorbing Coatings

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon M.; Howitt, Richard V.

    1990-01-01

    Carbon black and silicon carbide grit low reflectance additives. Report presents results of survey of candidate materials for use as attenuators of stray radiation in far-infrared telescopes. More than 40 reflectance spectra at 17 degrees incidence, in wave-length range from 20 to 500 micrometer, obtained from variety of coatings, binders, and additives.

  9. Variations on Black Themes: English, Black Literature.

    ERIC Educational Resources Information Center

    Randolph, Gloria D.

    Variations on Black Themes, an introductory course in the study of black literature, permits students to make cursory examination of representative works of many black writers for the purpose of identifying major writers and recurring themes. The course content includes: introduction to some works of major Black American authors; identification of…

  10. Infrared Thermometers

    ERIC Educational Resources Information Center

    Schaefers, John

    2006-01-01

    An infrared (IR) thermometer lab offers the opportunity to give science students a chance to measure surface temperatures, utilizing off-the-shelf technology. Potential areas of study include astronomy (exoplanets), electromagnetic spectrum, chemistry, evaporation rates, anatomy, crystal formation, and water or liquids. This article presents one…

  11. Infrared Thermometers

    ERIC Educational Resources Information Center

    Schaefers, John

    2006-01-01

    An infrared (IR) thermometer lab offers the opportunity to give science students a chance to measure surface temperatures, utilizing off-the-shelf technology. Potential areas of study include astronomy (exoplanets), electromagnetic spectrum, chemistry, evaporation rates, anatomy, crystal formation, and water or liquids. This article presents one…

  12. Infrared telescope

    NASA Technical Reports Server (NTRS)

    Karr, G. R.; Hendricks, J. B.

    1985-01-01

    The development of the Infrared Telescope for Spacelab 2 is discussed. The design, development, and testing required to interface a stationary superfluid helium dewar with a scanning cryostate capable of operating in the zero-g environment in the space shuttle bay is described.

  13. HOST GALAXY PROPERTIES OF THE SWIFT BAT ULTRA HARD X-RAY SELECTED ACTIVE GALACTIC NUCLEUS

    SciTech Connect

    Koss, Michael; Mushotzky, Richard; Veilleux, Sylvain; Winter, Lisa M.; Baumgartner, Wayne; Tueller, Jack; Gehrels, Neil; Valencic, Lynne

    2011-10-01

    We have assembled the largest sample of ultra hard X-ray selected (14-195 keV) active galactic nucleus (AGN) with host galaxy optical data to date, with 185 nearby (z < 0.05), moderate luminosity AGNs from the Swift BAT sample. The BAT AGN host galaxies have intermediate optical colors (u - r and g - r) that are bluer than a comparison sample of inactive galaxies and optically selected AGNs from the Sloan Digital Sky Survey (SDSS) which are chosen to have the same stellar mass. Based on morphological classifications from the RC3 and the Galaxy Zoo, the bluer colors of BAT AGNs are mainly due to a higher fraction of mergers and massive spirals than in the comparison samples. BAT AGNs in massive galaxies (log M{sub *} >10.5) have a 5-10 times higher rate of spiral morphologies than in SDSS AGNs or inactive galaxies. We also see enhanced far-infrared emission in BAT AGN suggestive of higher levels of star formation compared to the comparison samples. BAT AGNs are preferentially found in the most massive host galaxies with high concentration indexes indicative of large bulge-to-disk ratios and large supermassive black holes. The narrow-line (NL) BAT AGNs have similar intrinsic luminosities as the SDSS NL Seyferts based on measurements of [O III] {lambda}5007. There is also a correlation between the stellar mass and X-ray emission. The BAT AGNs in mergers have bluer colors and greater ultra hard X-ray emission compared to the BAT sample as a whole. In agreement with the unified model of AGNs, and the relatively unbiased nature of the BAT sources, the host galaxy colors and morphologies are independent of measures of obscuration such as X-ray column density or Seyfert type. The high fraction of massive spiral galaxies and galaxy mergers in BAT AGNs suggest that host galaxy morphology is related to the activation and fueling of local AGN.

  14. Blazars in Hard X-rays

    NASA Astrophysics Data System (ADS)

    Ghisellini, Gabriele

    2009-05-01

    Although blazars are thought to emit most of their luminosity in the γ-ray band, there are subclasses of them very prominent in hard X-rays. These are the best candidates to be studied by Simbol-X. They are at the extremes of the blazar sequence, having very small or very high jet powers. The former are the class of TeV emitting BL Lacs, whose synchrotron emission often peaks at tens of keV or more. The latter are the blazars with the most powerful jets, have high black hole masses accreting at high (i.e. close to Eddington) rates. These sources are predicted to have their high energy peak even below the MeV band, and therefore are very promising candidates to be studied with Simbol-X.

  15. Black oesophagus.

    PubMed

    Pereira, Olga; Figueira-Coelho, João; Picado, Bárbara; Costa, José Neves

    2013-01-29

    Acute oesophageal necrosis, also known as 'Black Oesophagus', is a rare endoscopic finding since its first description by Goldenberg in 1990. In endoscopic studies, the frequency ranged from 0.01% to 0.2%. The aetiology is undefined and is probably multifactorial. A 62-year-old woman, with chronic alcoholism, was admitted to the internal medicine department for dehydration and marked malnutrition problems. Melaena was detected, and oesophagogastroduodenoscopy showed black mucosa of the lower two-thirds of the oesophagus and candidiasis. The patient gradually recovered after conservative treatments (intravenous proton pump inhibitor and total parental nutrition) and fluconazole. Oesophagus stricture was developed after 1 month, and balloon dilatation was performed successfully.

  16. TIME-DEPENDENT INFRARED STUDIES.

    DTIC Science & Technology

    INFRARED RESEARCH, TIME , INFRARED PHENOMENA, INFRARED RADIATION, INFRARED SPECTROSCOPY, HIGH ALTITUDE, SOLAR ATMOSPHERE, TRANSMISSIONS(MECHANICAL), VIBRATION, QUANTUM THEORY, CALIBRATION, INFRARED SCANNING.

  17. Janka hardness using nonstandard specimens

    Treesearch

    David W. Green; Marshall Begel; William Nelson

    2006-01-01

    Janka hardness determined on 1.5- by 3.5-in. specimens (2×4s) was found to be equivalent to that determined using the 2- by 2-in. specimen specified in ASTM D 143. Data are presented on the relationship between Janka hardness and the strength of clear wood. Analysis of historical data determined using standard specimens indicated no difference between side hardness...

  18. [The black death in Norway].

    PubMed

    Oeding, P

    1990-06-30

    The old Icelandic annals tell that the Black Death came to Bergen, Norway, in 1349 with a ship from England. This was probably at the beginning of September. From Bergen the plague spread rapidly northwards and southwards along the coast and over land to Eastern Norway. The Black Death remained in Norway for approximately six months. The epidemic must have been started by infected black rats and rat fleas in the grain cargo of the ship. The account in the annals, and experiences from other countries, indicate that pneumonic plague was dominant in Bergen at the start of the epidemic. After that the Black Death must have spread partly as pneumonic plague but mainly probably as bubonic plague, transmitted via human fleas from person to person. The rats cannot have played a part except in the initial phase. The annals say that 2/3 of Norway's population died. This is probably a big exaggeration. The mortality in Norway can hardly have been more than 40-50%. Even this is high compared with an estimated mortality of approximately 33% in England and on the continent.

  19. Research on infrared imaging illumination model based on materials

    NASA Astrophysics Data System (ADS)

    Hu, Hai-he; Feng, Chao-yin; Guo, Chang-geng; Zheng, Hai-jing; Han, Qiang; Hu, Hai-yan

    2013-09-01

    In order to effectively simulate infrared features of the scene and infrared high light phenomenon, Based on the visual light illumination model, according to the optical property of all material types in the scene, the infrared imaging illumination models are proposed to fulfill different materials: to the smooth material with specular characteristic, adopting the infrared imaging illumination model based on Blinn-Phone reflection model and introducing the self emission; to the ordinary material which is similar to black body without highlight feature, ignoring the computation of its high light reflection feature, calculating simply the material's self emission and its reflection to the surrounding as its infrared imaging illumination model, the radiation energy under zero range of visibility can be obtained according to the above two models. The OpenGl rendering technology is used to construct infrared scene simulation system which can also simulate infrared electro-optical imaging system, then gets the synthetic infrared images from any angle of view of the 3D scenes. To validate the infrared imaging illumination model, two typical 3D scenes are made, and their infrared images are calculated to compare and contrast with the real collected infrared images obtained by a long wave infrared band imaging camera. There are two major points in the paper according to the experiment results: firstly, the infrared imaging illumination models are capable of producing infrared images which are very similar to those received by thermal infrared camera; secondly, the infrared imaging illumination models can simulate the infrared specular feature of relative materials and common infrared features of general materials, which shows the validation of the infrared imaging illumination models. Quantitative analysis shows that the simulation images are similar to the collected images in the aspects of main features, but their histogram distribution does not match very well, the

  20. Infrared floodlight

    DOEpatents

    Levin, Robert E.; English, George J.

    1986-08-05

    An infrared floodlight assembly designed particularly for security purposes and including a heat-conducting housing, a lens secured to the housing to provide a closure therefor, and a floodlight located within (and surrounded by) the housing. The floodlight combines the use of a tungsten halogen light source and dichroic hot and cold mirrors for directing substantially only infrared radiation toward the assembly's forward lens. Visible radiation is absorbed by the housing's interior wall(s) and, optionally, by a filter located between the floodlight and lens. An optional means may be used within the floodlight to reflect all forward radiation back toward the paraboloidal hot mirror or, alternatively, to reflect only visible radiation in this direction. The dichroic hot and cold mirrors preferably each comprise a glass substrate having multiple layers of titanium dioxide and silicon dioxide thereon.

  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. Black Eye: First Aid

    MedlinePlus

    First aid Black eye: First aid Black eye: First aid By Mayo Clinic Staff A black eye is caused by bleeding under the skin around the eye. Most injuries that cause a black eye aren't serious. But a black eye ...

  3. 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)

  4. 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…

  5. Infrared Arrays

    NASA Astrophysics Data System (ADS)

    McLean, I.; Murdin, P.

    2000-11-01

    Infrared arrays are small electronic imaging devices subdivided into a grid or `array' of picture elements, or pixels, each of which is made of a material sensitive to photons (ELECTROMAGNETIC RADIATION) with wavelengths much longer than normal visible light. Typical dimensions of currently available devices are about 27-36 mm square, and formats now range from 2048×2048 pixels for the near-infra...

  6. A gapless hard wall: magnetic catalysis in bulk and boundary

    NASA Astrophysics Data System (ADS)

    Bolognesi, Stefano; Laia, João N.; Tong, David; Wong, Kenny

    2012-07-01

    We study various aspects of fermions and their chiral condensates, both in the bulk of AdS4 spacetime and in the dual boundary theory. For the most part, we focus on a geometry with an infra-red hard wall. We show that, contrary to common lore, there exist boundary conditions in which the hard wall gives rise to a discrete, but gapless, fermionic spectrum. In such a setting, the presence of a magnetic field induces a bulk fermion condensate which spontaneously breaks CP invariance. We develop the holographic dictionary between composite operators and show that this bulk condensate has the interpretation of boundary magnetic catalysis involving a double-trace operator. Finally, we explain how one can replace the hard wall with bulk magnetic monopoles. In such a framework, magnetic catalysis can be viewed as a consequence of the Callan-Rubakov effect.

  7. Infrared backscattering

    NASA Technical Reports Server (NTRS)

    Bohren, Craig F.; Nevitt, Timothy J.; Singham, Shermila Brito

    1989-01-01

    All particles in the atmosphere are not spherical. Moreover, the scattering properties of randomly oriented nonspherical particles are not equivalent to those of spherical particles no matter how the term equivalent is defined. This is especially true for scattering in the backward direction and at the infrared wavelengths at which some atmospheric particles have strong absorption bands. Thus calculations based on Mie theory of infrared backscattering by dry or insoluble atmospheric particles are suspect. To support this assertion, it was noted that peaks in laboratory-measured infrared backscattering spectra show appreciable shifts compared with those calculated using Mie theory. One example is ammonium sulfate. Some success was had in modeling backscattering spectra of ammonium sulfate particles using a simple statistical theory called the continuous distribution of ellipsoids (CDE) theory. In this theory, the scattering properties of an ensemble are calculated. Recently a modified version of this theory was applied to measured spectra of scattering by kaolin particles. The particles were platelike, so the probability distribution of ellipsoidal shapes was chosen to reflect this. As with ammonium sulfate, the wavelength of measured peak backscattering is shifted longward of that predicted by Mie theory.

  8. Infrared retina

    DOEpatents

    Krishna, Sanjay [Albuquerque, NM; Hayat, Majeed M [Albuquerque, NM; Tyo, J Scott [Tucson, AZ; Jang, Woo-Yong [Albuquerque, NM

    2011-12-06

    Exemplary embodiments provide an infrared (IR) retinal system and method for making and using the IR retinal system. The IR retinal system can include adaptive sensor elements, whose properties including, e.g., spectral response, signal-to-noise ratio, polarization, or amplitude can be tailored at pixel level by changing the applied bias voltage across the detector. "Color" imagery can be obtained from the IR retinal system by using a single focal plane array. The IR sensor elements can be spectrally, spatially and temporally adaptive using quantum-confined transitions in nanoscale quantum dots. The IR sensor elements can be used as building blocks of an infrared retina, similar to cones of human retina, and can be designed to work in the long-wave infrared portion of the electromagnetic spectrum ranging from about 8 .mu.m to about 12 .mu.m as well as the mid-wave portion ranging from about 3 .mu.m to about 5 .mu.m.

  9. Overview: Hard Rock Penetration

    SciTech Connect

    Dunn, J.C.

    1992-08-01

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  10. Overview - Hard Rock Penetration

    SciTech Connect

    Dunn, James C.

    1992-03-24

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling Organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  11. Overview: Hard Rock Penetration

    SciTech Connect

    Dunn, J.C.

    1992-01-01

    The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

  12. Black Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Black Sea in eastern Russia is experiencing an ongoing phytoplankton bloom. This image, the most recent in a series that began in early may, shows the waters to be even more colorful than before. part of the increased brightness may be due to the presence of sun glint , especially in the center of the sea. However, more organisms appear to be present as well, their photosynthetic pigments reflecting different wavelengths of light.This Moderate Resolution Imaging Spectroradiometer (MODIS) image was captured on June 15, 2002.

  13. Black Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Black Sea in eastern Russia is experiencing an ongoing phytoplankton bloom. This image, the most recent in a series that began in early may, shows the waters to be even more colorful than before. part of the increased brightness may be due to the presence of sun glint , especially in the center of the sea. However, more organisms appear to be present as well, their photosynthetic pigments reflecting different wavelengths of light.This Moderate Resolution Imaging Spectroradiometer (MODIS) image was captured on June 15, 2002.

  14. Measuring the Hardness of Minerals

    ERIC Educational Resources Information Center

    Bushby, Jessica

    2005-01-01

    The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

  15. Black widow spider

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002858.htm Black widow spider To use the sharing features on this page, please enable JavaScript. The black widow spider has a shiny black body with a red ...

  16. Far infrared supplement: Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

    Gezari, D. Y.; Schmitz, M.; Mead, J. M.

    1984-01-01

    The Far Infrared Supplement: catalog of infrared observations summarizes all infrared astronomical observations at far infrared wavelengths published in the scientific literature between 1965 and 1982. The Supplement list contains 25% of the observations in the full catalog of infrared observations (C10), and essentially eliminates most visible stars from the listings. The Supplement is more compact than the main Catalog (it does not contain the bibliography and position index of the C10), and is intended for easy reference during astronomical observations.

  17. The asymptotic form of non-global logarithms, black disc saturation, and gluonic deserts

    NASA Astrophysics Data System (ADS)

    Neill, Duff

    2017-01-01

    We develop an asymptotic perturbation theory for the large logarithmic behavior of the non-linear integro-differential equation describing the soft correlations of QCD jet measurements, the Banfi-Marchesini-Smye (BMS) equation. This equation captures the late-time evolution of radiating color dipoles after a hard collision. This allows us to prove that at large values of the control variable (the non-global logarithm, a function of the infra-red energy scales associated with distinct hard jets in an event), the distribution has a gaussian tail. We compute the decay width analytically, giving a closed form expression, and find it to be jet geometry independent, up to the number of legs of the dipole in the active jet. Enabling the asymptotic expansion is the correct perturbative seed, where we perturb around an anzats encoding formally no real emissions, an intuition motivated by the buffer region found in jet dynamics. This must be supplemented with the correct application of the BFKL approximation to the BMS equation in collinear limits. Comparing to the asymptotics of the conformally related evolution equation encountered in small-x physics, the Balitisky-Kovchegov (BK) equation, we find that the asymptotic form of the non-global logarithms directly maps to the black-disc unitarity limit of the BK equation, despite the contrasting physical pictures. Indeed, we recover the equations of saturation physics in the final state dynamics of QCD.

  18. The asymptotic form of non-global logarithms, black disc saturation, and gluonic deserts

    DOE PAGES

    Neill, Duff

    2017-01-25

    Here, we develop an asymptotic perturbation theory for the large logarithmic behavior of the non-linear integro-differential equation describing the soft correlations of QCD jet measurements, the Banfi-Marchesini-Smye (BMS) equation. Furthermore, this equation captures the late-time evolution of radiating color dipoles after a hard collision. This allows us to prove that at large values of the control variable (the non-global logarithm, a function of the infra-red energy scales associated with distinct hard jets in an event), the distribution has a gaussian tail. We also compute the decay width analytically, giving a closed form expression, and find it to be jet geometrymore » independent, up to the number of legs of the dipole in the active jet. By enabling the asymptotic expansion we find that the perturbative seed is correct; we perturb around an anzats encoding formally no real emissions, an intuition motivated by the buffer region found in jet dynamics. This must be supplemented with the correct application of the BFKL approximation to the BMS equation in collinear limits. Comparing to the asymptotics of the conformally related evolution equation encountered in small-x physics, the Balitisky-Kovchegov (BK) equation, we find that the asymptotic form of the non-global logarithms directly maps to the black-disc unitarity limit of the BK equation, despite the contrasting physical pictures. Indeed, we recover the equations of saturation physics in the final state dynamics of QCD.« less

  19. 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)

  20. 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)

  1. Beta Backscatter Measures the Hardness of Rubber

    NASA Technical Reports Server (NTRS)

    Morrissey, E. T.; Roje, F. N.

    1986-01-01

    Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

  2. Thin coatings and films hardness evaluation

    NASA Astrophysics Data System (ADS)

    Matyunin, V. M.; Marchenkov, A. Yu; Demidov, A. N.; Karimbekov, M. A.

    2016-10-01

    The existing thin coatings and films hardness evaluation methods based on indentation with pyramidal indenter on various scale levels are expounded. The impact of scale factor on hardness values is performed. The experimental verification of several existing hardness evaluation methods regarding the substrate hardness value and the “coating - substrate” composite hardness value is made.

  3. Beta Backscatter Measures the Hardness of Rubber

    NASA Technical Reports Server (NTRS)

    Morrissey, E. T.; Roje, F. N.

    1986-01-01

    Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

  4. Infrared Heaters

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The heating units shown in the accompanying photos are Panelbloc infrared heaters, energy savers which burn little fuel in relation to their effective heat output. Produced by Bettcher Manufacturing Corporation, Cleveland, Ohio, Panelblocs are applicable to industrial or other facilities which have ceilings more than 12 feet high, such as those pictured: at left the Bare Hills Tennis Club, Baltimore, Maryland and at right, CVA Lincoln- Mercury, Gaithersburg, Maryland. The heaters are mounted high above the floor and they radiate infrared energy downward. Panelblocs do not waste energy by warming the surrounding air. Instead, they beam invisible heat rays directly to objects which absorb the radiation- people, floors, machinery and other plant equipment. All these objects in turn re-radiate the energy to the air. A key element in the Panelbloc design is a coating applied to the aluminized steel outer surface of the heater. This coating must be corrosion resistant at high temperatures and it must have high "emissivity"-the ability of a surface to emit radiant energy. The Bettcher company formerly used a porcelain coating, but it caused a production problem. Bettcher did not have the capability to apply the material in its own plant, so the heaters had to be shipped out of state for porcelainizing, which entailed extra cost. Bettcher sought a coating which could meet the specifications yet be applied in its own facilities. The company asked The Knowledge Availability Systems Center, Pittsburgh, Pennsylvania, a NASA Industrial Applications Center (IAC), for a search of NASA's files

  5. A VARIABLE MID-INFRARED SYNCHROTRON BREAK ASSOCIATED WITH THE COMPACT JET IN GX 339-4

    SciTech Connect

    Gandhi, P.; Khangulyan, D.; Blain, A. W.; Russell, D. M.; Markoff, S.; Casella, P.; Malzac, J.; Corbel, S.; D'Avanzo, P.; Lewis, F. W.; Cadolle Bel, M.; Goldoni, P.; Wachter, S.; Mainzer, A.

    2011-10-10

    Many X-ray binaries remain undetected in the mid-infrared, a regime where emission from their compact jets is likely to dominate. Here, we report the detection of the black hole binary GX 339-4 with the Wide-field Infrared Survey Explorer (WISE) during a very bright, hard accretion state in 2010. Combined with a rich contemporaneous multiwavelength data set, clear spectral curvature is found in the infrared, associated with the peak flux density expected from the compact jet. An optically thin slope of {approx} -0.7 and a jet radiative power of >6 x 10{sup 35} erg s{sup -1} (d/8 kpc){sup 2} are measured. A {approx}24 hr WISE light curve shows dramatic variations in mid-infrared spectral slope on timescales at least as short as the satellite orbital period {approx}95 minutes. There is also significant change during one pair of observations spaced by only 11 s. These variations imply that the spectral break associated with the transition from self-absorbed to optically thin jet synchrotron radiation must be varying across the full wavelength range of {approx}3-22 {mu}m that WISE is sensitive to, and more. Based on four-band simultaneous mid-infrared detections, the break is constrained to frequencies of {approx}4.6{sup +3.5} {sub -2.0} x 10{sup 13} Hz in at least two epochs of observation, consistent with a magnetic field B {approx} 1.5({+-} 0.8) x 10{sup 4} G assuming a single-zone synchrotron emission region. The observed variability implies that either B or the size of the acceleration zone above the jet base is being modulated by factors of {approx}10 on relatively short timescales.

  6. On the Nature of the Hard X-ray Sources SWIFT J1907.3-2050, IGR J12123-5802 and IGR J19552+0044

    NASA Technical Reports Server (NTRS)

    Bernardini, F.; De Martino, D.; Mukai, K.; Falanga, M.; Andruchow, I.; Bonnet-Bidaud, J.-M.; Masetti, N.; Gonzalez Buitrago, D. H.; Mouchet, M.; Tovmassian, G.

    2013-01-01

    The INTEGRAL and Swift hard X-ray surveys have identified a large number of new sources, among which many are proposed as Cataclysmic Variables (CVs). Here we present the first detailed study of three X-ray selected CVs, Swift J1907.3-2050, IGRJ12123-5802, and IGRJ19552+0044 based on XMM-Newton, Suzaku, Swift observations and ground based optical and archival near-infrared/infrared data. Swift J1907.3-2050 is highly variable from hours to months-years at all wavelengths. No coherent X-ray pulses are detected but rather transient features. The X-ray spectrum reveals a multi-temperature optically thin plasma absorbed by complex neutral material and a soft black body component arising from a small area. These characteristics are remarkably similar to those observed in magnetic CVs. A supra-solar abundance of nitrogen could arise from nuclear processed material from the donor star. Swift J1907.3-2050 could be a peculiar magnetic CV with the second longest (20.82 hours) binary period. IGRJ12123-5802 is variable in the X-rays on a timescale of greater than or approximately 7.6 hours. No coherent pulsations are detected, but its spectral characteristics suggest that it could be a magnetic CV of the Intermediate Polar (IP) type. IGRJ19552+0044 shows two X-ray periods, approximately 1.38 hours and approximately 1.69 hours and a X-ray spectrum characterized by a multi-temperature plasma with little absorption. We derive a low accretion rate, consistent with a CV below the orbital period gap. Its peculiar near-infrared/infrared spectrum suggests a contribution from cyclotron emission. It could either be a pre-polar or an IP with the lowest degree of asynchronism.

  7. Black chrome on commercially electroplated tin as a solar selecting coating

    NASA Technical Reports Server (NTRS)

    Mcdonald, G. E.

    1977-01-01

    The reflectance properties of black chrome electroplated on commercially electroplated tin were measured for various black chrome plating times for both the solar and infrared spectrum. The values of absorptance and emittance were calculated from the measured reflectance values. The results indicate that the optimum combination of the highest absorptance in the solar region and the lowest emittance in the infrared of the black chrome plated on commercially electroplated tin is obtained for a black chrome plating time of between one and two minutes.

  8. Dissonant black droplets and black funnels

    NASA Astrophysics Data System (ADS)

    Fischetti, Sebastian; Santos, Jorge E.; Way, Benson

    2017-08-01

    A holographic field theory on a fixed black hole background has a gravitational dual represented by a black funnel or a black droplet. These states are ‘detuned’ when the temperature of the field theory near the horizon does not match the temperature of the background black hole. In particular, the gravitational dual to the Boulware state must be a detuned solution. We construct detuned droplets and funnels dual to a Schwarzschild background and show that the Boulware phase is represented by a droplet. We also construct hairy black droplets associated to a low-temperature scalar condensation instability and show that they are thermodynamically preferred to their hairless counterparts.

  9. Nanoindentation hardness of mineralized tissues.

    PubMed

    Oyen, Michelle L

    2006-01-01

    A series elastic and plastic deformation model [Sakai, M., 1999. The Meyer hardness: a measure for plasticity? Journal of Materials Research 14(9), 3630-3639] is used to deconvolute the resistance to plastic deformation from the plane strain modulus and contact hardness parameters obtained in a nanoindentation test. Different functional dependencies of contact hardness on the plane strain modulus are examined. Plastic deformation resistance values are computed from the modulus and contact hardness for engineering materials and mineralized tissues. Elastic modulus and plastic deformation resistance parameters are used to calculate elastic and plastic deformation components, and to examine the partitioning of indentation deformation between elastic and plastic. Both the numerical values of plastic deformation resistance and the direct computation of deformation partitioning reveal the intermediate mechanical responses of mineralized composites when compared with homogeneous engineering materials.

  10. Some preliminary evaluations of black coating on aluminium AA2219 alloy produced by plasma electrolytic oxidation (PEO) process for space applications

    NASA Astrophysics Data System (ADS)

    Shrestha, S.; Merstallinger, A.; Sickert, D.; Dunn, B. D.

    2003-09-01

    This paper describes the results of a study of a black coating produced on aluminium AA2219 alloy using a process that involves creation of a hard ceramic oxide layer on the surface of the alloy by plasma electrolytic oxidation (PEO) known as the 'KERONITE®' process. Coating microstructure has been examined and the coating characteristics such as porosity, hardness, adhesion and phase composition were measured. The thermo-optical properties such as solar absorptance 'as' and normal infrared emittance 'en-IR' of the coating were measured in the 'as-prepared' condition and after environmental exposures to humidity, thermal cycling and UV-radiation in vacuum and to thermal shock. Comparison was made with alternative coatings produced using standard black anodising processes. The study also looked at the cold welding and friction behaviours of the coated alloy in vacuum and in an ambient laboratory environment. Standard spacecraft materials tests were conducted on the coated disc against an AISI 52100 steel ball and also against a coated pin using a pin-on-disc apparatus. Parameters such as friction coefficient and wear depth were measured and the cold welding behaviours were investigated. Test results were compared with the data generated for NiCr plated and anodised coatings. Corrosion performance was assessed using a salt spray exposure test and using an accelerated electrochemical test method. In addition, the study looked at the effect of post coating sealing with a sol-gel solution.

  11. Far infrared supplement: Catalog of infrared observations

    NASA Technical Reports Server (NTRS)

    Gezari, D. Y.; Schmitz, M.; Mead, J. M.

    1982-01-01

    The development of a new generation of orbital, airborne and ground-based infrared astronomical observatory facilities, including the infrared astronomical satellite (IRAS), the cosmic background explorer (COBE), the NASA Kuiper airborne observatory, and the NASA infrared telescope facility, intensified the need for a comprehensive, machine-readable data base and catalog of current infrared astronomical observations. The Infrared Astronomical Data Base and its principal data product, this catalog, comprise a machine-readable library of infrared (1 micrometer to 1000 micrometers) astronomical observations published in the scientific literature since 1965.

  12. Far infrared supplement: Catalog of infrared observations

    NASA Astrophysics Data System (ADS)

    Gezari, Daniel Y.; Schmitz, Marion; Mead, Jaylee M.

    1982-10-01

    The development of a new generation of orbital, airborne and ground-based infrared astronomical observatory facilities, including the infrared astronomical satellite (IRAS), the cosmic background explorer (COBE), the NASA Kuiper airborne observatory, and the NASA infrared telescope facility, intensified the need for a comprehensive, machine-readable data base and catalog of current infrared astronomical observations. The Infrared Astronomical Data Base and its principal data product, this catalog, comprise a machine-readable library of infrared (1 micrometer to 1000 micrometers) astronomical observations published in the scientific literature since 1965.

  13. 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;…

  14. 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.

  15. QPOs from black-hole candidates

    NASA Astrophysics Data System (ADS)

    Kitamoto, Shunji

    1989-11-01

    Ginga observed the following black-hole candidates: Cyg X-1, LMC X-1, LMC X-3, GX339-4, GS2000+25 and GS2023+39. Observed properties about Quasi-Periodic Oscillation (QPO) and time variation of these black hole candidates are presented. The observed properties of the time variations of GX 339-4 and LMC X-1 suggest that the energy spectrum is composed of a soft and a hard component. The hard component of GX339-4 has two states. Rapid alternations of these states suggest that the size of the hard component emitting region is less than 2.8 times 10 to the 9th power cm. Significant time lags of high energy and also low energy X-rays in reference to the X-rays in the energy range between 2.3 keV were found. Cyg X-1 and GS2023+339 do not show QPO but they show violent time variation. These sources also show hard X-ray lags.

  16. Growing supermassive black holes in the late stages of galaxy mergers are heavily obscured

    NASA Astrophysics Data System (ADS)

    Ricci, C.; Bauer, F. E.; Treister, E.; Schawinski, K.; Privon, G. C.; Blecha, L.; Arevalo, P.; Armus, L.; Harrison, F.; Ho, L. C.; Iwasawa, K.; Sanders, D. B.; Stern, D.

    2017-01-01

    Mergers of galaxies are thought to cause significant gas inflows to the inner parsecs, which can activate rapid accretion onto supermassive black holes (SMBHs), giving rise to Active Galactic Nuclei (AGN). During a significant fraction of this process, SMBHs are predicted to be enshrouded by gas and dust. Studying 52 galactic nuclei in infrared-selected local Luminous and Ultra-luminous infrared galaxies in different merger stages in the hard X-ray band, where radiation is less affected by absorption, we find that the amount of material around SMBHs increases during the last phases of the merger. We find that the fraction of Compton-thick (CT, N_ H≥ 10^{24} cm^{-2}) AGN in late merger galaxies is higher (f_ CT=65^{+12}_{-13}%) than in local hard X-ray selected AGN (f CT = 27 ± 4%), and that obscuration reaches its maximum when the nuclei of the two merging galaxies are at a projected distance of D12 ≃ 0.4 - 10.8 kiloparsecs (f_ CT=77_{-17}^{+13}%). We also find that all AGN of our sample in late merger galaxies have N_ H> 10^{23} cm^{-2}, which implies that the obscuring material covers 95^{+4}_{-8}% of the X-ray source. These observations show that the material is most effectively funnelled from the galactic scale to the inner tens of parsecs during the late stages of galaxy mergers, and that the close environment of SMBHs in advanced mergers is richer in gas and dust with respect to that of SMBHs in isolated galaxies, and cannot be explained by the classical AGN unification model in which the torus is responsible for the obscuration.

  17. Surfing a Black Hole

    NASA Astrophysics Data System (ADS)

    2002-10-01

    . PR Photo 23b/02 : NACO image of the central region of the Milky Way (close-up) . PR Photo 23c/02 : Orbit of the star "S2" around the central Black Hole. PR Video Clip 02/02 : Motion of "S2" and other stars around the central Black Hole. Quasars and Black Holes Ever since the discovery of the quasars (quasi-stellar radio sources) in 1963, astrophysicists have searched for an explanation of the energy production in these most luminous objects in the Universe. Quasars reside at the centres of galaxies, and it is believed that the enormous energy emitted by these objects is due to matter falling onto a supermassive Black Hole, releasing gravitational energy through intense radiation before that material disappears forever into the hole (in physics terminology: "passes beyond the event horizon" [4]). To explain the prodigious energy production of quasars and other active galaxies, one needs to conjecture the presence of black holes with masses of one million to several billion times the mass of the Sun. Much evidence has been accumulating during the past years in support of the above "accreting black hole" model for quasars and other galaxies, including the detection of dark mass concentrations in their central regions. However, an unambiguous proof requires excluding all possible other, non-black hole configurations of the central mass concentration. For this, it is imperative to determine the shape of the gravitational field very close to the central object - and this is not possible for the distant quasars due to technological limitations of the currently available telescopes. The centre of the Milky Way ESO PR Photo 23a/02 ESO PR Photo 23a/02 [Preview - JPEG: 400 x 427 pix - 95k [Normal - JPEG: 800 x 853 pix - 488k] Caption : PR Photo 23a/02 is a reproduction of an image of the innermost area of the Milky Way, only a few light-years across, obtained in mid-2002 with the NACO instrument [3] at the 8.2-m VLT YEPUN telescope. It combines frames in three infrared

  18. Hardness, density, and shrinkage characteristics of silk-oak from Hawaii

    Treesearch

    R. L. Youngs

    1964-01-01

    Shrinkage, specific gravity, and hardness of two shipments of silk-oak (Grevillea robusta) from Hawaii were evaluated to provide basic information pertinent to the use of the wood for cabinet and furniture purposes. The wood resembles Hawaii-grown shamel ash (Fraxinus uhdei ) in the properties evaluated. Shrinkage compares well with that of black cherry, silver maple,...

  19. Examining a Sample of Black Deaf Individuals on the Deaf Acculturation Scale

    ERIC Educational Resources Information Center

    Nelson Schmitt, Shawn S.; Leigh, Irene W.

    2015-01-01

    The current study sought to identify and analyze how Black deaf and hard-of-hearing people conceptualize their deaf and hard-of-hearing identities. That is, what cultural and linguistic factors are involved and how do they interact? An existing measure of Deaf cultural identity, the Deaf Acculturation Scale (DAS), was used to evaluate these…

  20. Examining a Sample of Black Deaf Individuals on the Deaf Acculturation Scale

    ERIC Educational Resources Information Center

    Nelson Schmitt, Shawn S.; Leigh, Irene W.

    2015-01-01

    The current study sought to identify and analyze how Black deaf and hard-of-hearing people conceptualize their deaf and hard-of-hearing identities. That is, what cultural and linguistic factors are involved and how do they interact? An existing measure of Deaf cultural identity, the Deaf Acculturation Scale (DAS), was used to evaluate these…

  1. Searching for Dual AGNs in Galaxy Mergers: Understanding Double-Peaked [O III] and Ultra Hard X-rays as Selection Method

    NASA Astrophysics Data System (ADS)

    McGurk, Rosalie C.; Max, Claire E.; Medling, Anne; Shields, Gregory A.

    2015-01-01

    When galaxies merge, gas accretes onto both central supermassive black holes. Thus, one expects to see close pairs of active galactic nuclei (AGNs), or dual AGNs, in a fraction of galaxy mergers. However, finding them remains a challenge. The presence of double-peaked [O III] or of ultra hard X-rays have been proposed as techniques to select dual AGNs efficiently. We studied a sample of double-peaked narrow [O III] emitting AGNs from SDSS DR7. By obtaining new and archival high spatial resolution images taken with the Keck 2 Laser Guide Star Adaptive Optics system and the near-infrared (IR) camera NIRC2, we showed that 30% of double-peaked [O III] emission line SDSS AGNs have two spatial components within a 3' radius. However, spatially resolved spectroscopy or X-ray observations are needed to confirm these galaxy pairs as systems containing two AGNs. We followed up these spatially-double candidate dual AGNs with integral field spectroscopy from Keck OSIRIS and Gemini GMOS and with long-slit spectroscopy from Keck NIRSPEC and Shane Kast Double Spectrograph. We find double-peaked emitters are caused sometimes by dual AGN and sometimes by outflows or narrow line kinematics. We also performed Chandra X-ray ACIS-S observations on 12 double-peaked candidate dual AGNs. Using our observations and 8 archival observations, we compare the distribution of X-ray photons to our spatially double near-IR images, measure X-ray luminosities and hardness ratios, and estimate column densities. By assessing what fraction of double-peaked emission line SDSS AGNs are true dual AGNs, we can better determine whether double-peaked [O III] is an efficient dual AGN indicator and constrain the statistics of dual AGNs. A second technique to find dual AGN is the detection of ultra hard X-rays by the Swift Burst Alert Telescope. We use CARMA observations to measure and map the CO(1-0) present in nearby ultra-hard X-ray Active Galactic Nuclei (AGNs) merging with either a quiescent companion

  2. 'Diamondlike' carbon films - Optical absorption, dielectric properties, and hardness dependence on deposition parameters

    NASA Technical Reports Server (NTRS)

    Natarajan, V.; Lamb, J. D.; Woollam, J. A.; Liu, D. C.; Gulino, D. A.

    1985-01-01

    An RF plasma deposition system was used to prepare amorphous 'diamondlike' carbon films. The source gases for the RF system include methane, ethylene, propane, and propylene, and the parameters varied were power, dc substrate bias, and postdeposition anneal temperature. Films were deposited on various substrates. The main diagnostics were optical absorption in the visible and in the infrared, admittance as a function of frequency, hardness, and Auger and ESCA spectroscopy. Band gap is found to depend strongly on RF power level and band gaps up to 2.7 eV and hardness up to 7 Mohs were found. There appears to be an inverse relationship between hardness and optical band gap.

  3. 'Diamondlike' carbon films - Optical absorption, dielectric properties, and hardness dependence on deposition parameters

    NASA Technical Reports Server (NTRS)

    Natarajan, V.; Lamb, J. D.; Woollam, J. A.; Liu, D. C.; Gulino, D. A.

    1985-01-01

    An RF plasma deposition system was used to prepare amorphous 'diamondlike' carbon films. The source gases for the RF system include methane, ethylene, propane, and propylene, and the parameters varied were power, dc substrate bias, and postdeposition anneal temperature. Films were deposited on various substrates. The main diagnostics were optical absorption in the visible and in the infrared, admittance as a function of frequency, hardness, and Auger and ESCA spectroscopy. Band gap is found to depend strongly on RF power level and band gaps up to 2.7 eV and hardness up to 7 Mohs were found. There appears to be an inverse relationship between hardness and optical band gap.

  4. Reproducing Black's experiments: freezing point depression and supercooling of water

    NASA Astrophysics Data System (ADS)

    Güémez, J.; Fiolhais, C.; Fiolhais, M.

    2002-01-01

    We carried out two historical experiments referred to by Joseph Black, one on freezing mixtures of salted water with ice and another on freezing supercooled pure water by a small disturbance. The results confirm thermodynamical predictions for the depression of the freezing point of salted water and for the latent heat of freezing of supercooled water respectively, which came after Black. The depression of the freezing point can hardly be fitted in the framework of the caloric theory of heat, which was taken for granted by Black, and the instantaneous freezing of supercooled water also poses some difficulties for that theory.

  5. Optical charaterization of black appliques

    NASA Astrophysics Data System (ADS)

    Snail, Keith A.; Brown, Dennis P.; Costantino, Joseph P.; Shemano, Wendy C.; Schmidt, Carl W.; Lynn, William F.; Seaman, Christopher L.; Knowles, Timothy R.

    1996-11-01

    For some stray light applications, it may be advantageous to use a black applique rather than a conventional black coating. Appliques consist of a free-standing sheet of black material and an adhesive or other means for attaching the applique to a substrate. In this paper the optical scatter in the visible and infrared of black appliques from Battelle, Dupont, Edmund Scientific, Energy Science Laboratory, Inc. (ESLI), Rippey and Rodel is reported and compared to Martin Black. The Rippey and Rodel appliques are sold as polishing cloths for the semiconductor industry, whereas the ESLI applique was originally developed as a low sputter yield coating. The Battelle applique consists of a carbon loaded polyurethane film with a surface which is heat molded into a micro-grooved pattern. The ESLI applique consists of high aspect ratio fibers mounted in an adhesive base and was the blackest applique of all those investigated. For an incidence angle of 10 degrees, a scattering angle of 45 degrees and a wavelength of 632.8 nm, the BRDF of the best ESLI applique was 3 multiplied by 10-4, compared to 1 multiplied by 10-3 for the best Battelle applique, 1.5 multiplied by 10-3 for a representative Martin Black sample and 1.8 multiplied by 10-3 for the Edmund applique. The Battelle applique is quasi-diffuse due to its surface microstructure, with a higher BRDF (2-5 multiplied by 10-3) at scatter angles less than 15 degrees For a wavelength of 10.6 micrometer, an incidence angle of 7.5 degrees and a scatter angle of 45 degrees, the BRDF of the ESLI coating (1 multiplied by 10-3) was slightly higher than Martin Black (8 multiplied by 10 -4), with the Battelle applique exhibiting strong dependences on scatter angle and groove orientation. In the 2 - 14 micrometer spectral range, the directional hemispherical reflectance of the ESLI coating at a 20 degree incidence angle is below 0.45% and only weakly dependent on incidence angle to 60 degrees. In- plane and cross-plane BRDF

  6. Infrared Measurements of Possible IR Filter Materials

    NASA Astrophysics Data System (ADS)

    Koller, Daniel; Ediss, G. A.; Mihaly, Laszlo; Carr, G. L.

    A Fourier Transform Infrared Spectrometer (FTS) was used to obtain the transmission spectra of candidate materials for use as infrared (IR) filters in cryogenic receivers. The data cover the range from 50 cm-1 (~1.5 THz), well below the peak of the 300 K black body spectrum, to 5000 cm-1 (~150 THz). Z-cut quartz, Goretex, Zitex G and Zitex A, High Density Polyethylene (HDPE), Teflon (PTFE), Fluorogold and Black Polyethylene were measured. The relative effectiveness of each material as a filter is determined by integrating the transmission spectrum multiplied by the Planck distribution to obtain a normalized attenuation for the mid-IR band. Measurements at both room temperature and 8 K are compared.

  7. Infrared Measurements of Possible IR Filter Materials

    SciTech Connect

    Koller,D.; Ediss, G.; Mihaly, L.; Carr, G.

    2006-01-01

    A Fourier Transform Infrared Spectrometer (FTS) was used to obtain the transmission spectra of candidate materials for use as infrared (IR) filters in cryogenic receivers. The data cover the range from 50 cm-1 ({approx}1.5 THz), well below the peak of the 300 K black body spectrum, to 5000 cm-1 ({approx}150 THz), Z-cut quartz, Gore-Tex, Zitex G and Zitex A, High Density Polyethylene (HDPE), Teflon (PTFE), Fluorogold and Black Polyethylene were measured. The relative effectiveness of each material as a filter is determined by integrating the transmission spectrum multiplied by the Planck distribution to obtain a normalized attenuation for the mid-IR band. Measurements at both room temperature and 8 K are compared.

  8. Far-infrared surveys of the sky.

    PubMed

    Hoffmann, W F; Woolf, N J; Frederick, C L; Low, F J

    1967-07-14

    A series of far-infrared surveys of the sky is searching for thermal radiation from interstellar grains and for other localized sources of far-infrared radiation. A balloon-borne germanium bolometer, cooled by liquid helium, is used in association with a telescope and spectral filters. During two initial flights the response to a black-body source was mainly between 300 and 360 microns. Approximately half the celestial sphere was surveyed, including most of the northern Milky Way. The angular resolution was 2 degrees. Moon was the only source of thermal radiation detected. The upper limit on the differential flux, relative to background, from other sources was 2 x 10(-23) watt per square centimeter per hertz, corresponding to an antenna temperature of 0.6 degrees K in the Rayleigh-Jeans approximation, or 10 degrees K for a black body.

  9. Electrically conductive black optical paint

    NASA Technical Reports Server (NTRS)

    Birnbaum, M. M.; Metzler, E. C.; Cleland, E. L.

    1983-01-01

    An electrically conductive flat black paint has been developed for use on the Galileo spacecraft which will orbit Jupiter in the late 1980s. The paint, designed for equipment operating in high-energy radiation fields, has multipurpose functions. Its electrical conductivity keeps differential charging of the spacecraft external surfaces and equipment to a minimum, preventing the buildup of electrostatic fields and arcing. Its flat black aspect minimizes the effects of stray light and unwanted reflectances, when used in optical instruments and on sunshades. Its blackness is suitable, also, for thermal control, when the paint is put on spacecraft surfaces. The paint has good adherence properties, as measured by tape tests, when applied properly to a surface. The electrically conductive paint which was developed has the following characteristics: an electrical resistivity of 5 x 10 to the 7th ohms per square; a visual light total reflectance of approximately 5 percent; an infrared reflectance of 0.13 measured over a spectrum from 10 to the (-5.5) power to 0.001 meter; a solar absorptivity, alpha-s, of 0.93, and a thermal emissivity, epsilon, of 0.87, resulting in an alpha-s/epsilon of 1.07. The formula for making the paint and the process for applying it are described.

  10. 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

  11. Searching for High-energy, Horizon-scale Emissions from Galactic Black Hole Transients during Quiescence

    NASA Astrophysics Data System (ADS)

    Lin, L. C.-C.; Pu, Hung-Yi; Hirotani, Kouichi; Kong, Albert K. H.; Matsushita, Satoki; Chang, Hsiang-Kuang; Inoue, Makoto; Tam, Pak-Hin T.

    2017-08-01

    We search for the gamma-ray counterparts of stellar-mass black holes using the long-term Fermi archive to investigate the electrostatic acceleration of electrons and positrons in the vicinity of the event horizon. We achieve this by applying the pulsar outer-gap model to their magnetospheres. When a black hole transient (BHT) is in a low-hard or quiescent state, the radiatively inefficient accretion flow cannot emit enough MeV photons that are required to sustain the force-free magnetosphere in the polar funnel via two-photon collisions. In this charge-starved gap region, an electric field arises along the magnetic field lines to accelerate electrons and positrons into ultra-relativistic energies. These relativistic leptons emit copious Gamma-rays via the curvature and inverse-Compton (IC) processes. It is found that these gamma-ray emissions exhibit a flaring activity when the plasma accretion rate typically stays between 0.01% and 0.005% of the Eddington value for rapidly rotating, stellar-mass black holes. By analyzing the detection limit determined from archival Fermi/Large Area Telescope data, we find that the 7-year averaged duty cycle of such flaring activities should be less than 5% and 10% for XTE J1118+480 and 1A 0620-00, respectively, and that the detection limit is comparable to the theoretical prediction for V404 Cyg. It is predicted that the gap emission can be discriminated from the jet emission if we investigate the high-energy spectral behavior or observe nearby BHTs during deep quiescence simultaneously in infrared wavelength and very-high energies.

  12. Quantitative analysis of incipient mineral loss in hard tissues

    NASA Astrophysics Data System (ADS)

    Matvienko, Anna; Mandelis, Andreas; Hellen, Adam; Jeon, Raymond; Abrams, Stephen; Amaechi, Bennett

    2009-02-01

    A coupled diffuse-photon-density-wave and thermal-wave theoretical model was developed to describe the biothermophotonic phenomena in multi-layered hard tissue structures. Photothermal Radiometry was applied as a safe, non-destructive, and highly sensitive tool for the detection of early tooth enamel demineralization to test the theory. Extracted human tooth was treated sequentially with an artificial demineralization gel to simulate controlled mineral loss in the enamel. The experimental setup included a semiconductor laser (659 nm, 120 mW) as the source of the photothermal signal. Modulated laser light generated infrared blackbody radiation from teeth upon absorption and nonradiative energy conversion. The infrared flux emitted by the treated region of the tooth surface and sub-surface was monitored with an infrared detector, both before and after treatment. Frequency scans with a laser beam size of 3 mm were performed in order to guarantee one-dimensionality of the photothermal field. TMR images showed clear differences between sound and demineralized enamel, however this technique is destructive. Dental radiographs did not indicate any changes. The photothermal signal showed clear change even after 1 min of gel treatment. As a result of the fittings, thermal and optical properties of sound and demineralized enamel were obtained, which allowed for quantitative differentiation of healthy and non-healthy regions. In conclusion, the developed model was shown to be a promising tool for non-invasive quantitative analysis of early demineralization of hard tissues.

  13. Infrared Emission from the Smallest Active Galaxies

    NASA Astrophysics Data System (ADS)

    Barth, Aaron; Greene, Jenny; Ho, Luis

    2006-05-01

    Virtually all of our current knowledge of black hole demographics, both in nearby inactive galaxies and in AGNs, comes from observations of black holes with masses between a few million and a few billion solar masses in host galaxies with stellar velocity dispersions between about 70 and 400 km/sec. Searching for smaller black holes in low-mass galaxies can yield important clues to the origin and early evolution of supermassive black holes, and AGN surveys are the best available way to identify such objects. Using the Sloan Digital Sky Survey, we have identified 19 Seyfert 1 galaxies with black hole mass below 10^6 solar masses (Greene & Ho 2004), and 20 Seyfert 2 galaxies having stellar velocity dispersions smaller than 70 km/sec as determined by new Keck observations. These AGN samples offer a unique opportunity to study the very early growth stages of black holes and their host galaxies. Spitzer observations of mid-infrared emission will be the best available calorimeter of the energetics of these tiny AGNs. Our primary goal is to determine the infrared contribution to the bolometric luminosities, which will be a key to understanding the black hole accretion rates. From the infrared spectral shapes we will constrain the dust temperatures and search for silicate features in emission or absorption that may indicate the presence of an obscuring torus, and which will help to determine whether the Type 1 and Type 2 objects differ primarily as a result of our viewing angle, as in classic AGN unified models. PAH features and narrow emission lines will be used to diagnose the relative contributions of AGN and star formation to the infrared luminosity. To accomplish these goals, we request IRS staring-mode spectroscopy in the SL2, SL1, LL2, and LL1 settings for our Sloan-selected sample of 19 Seyfert 1s and 20 Seyfert 2s, as well as NGC 4395 and POX 52, which are the prototypical nearby examples of Seyfert nuclei in dwarf host galaxies.

  14. 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)

  15. Survey of material for an infrared-opaque coating

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon M.; Howitt, Richard V.

    1986-01-01

    More than 40 reflectance spectra in the range from 20 to 500 microns have been obtained of a variety of coatings, binders, and additives to identify promising components of an infrared-opaque coating for the Space Infrared Telescope Facility. Certain combinations of materials showed a specular reflectance below 0.1 throughout the spectral range measured. In addition to estimating the optical constants of several combination coatings, this survey also supports three qualitative conclusions: (1) promising 'off-the-shelf' binders of different additives are Chemglaze Z-306, ECP-2200, and De Soto Black; (2) carbon black is very effective reducing far-infrared reflectance; and (3) the far-infrared reflectance from coatings containing 80 SiC grit is consistently lower than that from similar coatings containing TlBr powder.

  16. Survey of Material for an Infrared-Opaque Coating

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon M.; Howitt, Richard V.

    1986-01-01

    More than 40 reflectance spectra in the range from 20 to 500 microns have been obtained for a variety of coatings, binders, and additives to identify promising components of an infrared-opaque coating for the Space Infrared Telescope Facility. Certain combinations of materials showed a specular reflectance below 0.1 throughout the spectral range measured. In addition to estimating the optical constants of several combination coatings, this survey also supports three qualitative conclusions: (1) promising off-the-shelf binders of different additives are Chemglaze Z-306, ECP-2200, and De Soto Black; (2) carbon black is very effective in reducing far-infrared reflectance; (3) the far-infrared reflectance from coatings containing 80 SiC grit is consistently lower than that from similar coatings containing TiBr powder.

  17. Chemical and Electrochemical Synthesis of Platinum Black.

    PubMed

    Stanca, S E; Hänschke, F; Ihring, A; Zieger, G; Dellith, J; Kessler, E; Meyer, H-G

    2017-04-21

    We present electrochemical and chemical synthesis of platinum black at room temperature in aqueous and non-aqueous media. X-ray analysis established the purity and crystalline nature. The electron micrographs indicate that the nanostructures consist of platinum crystals that interconnect to form porous assemblies. Additionally, the electron micrographs of the platinum black thin layer, which was electrochemically deposited on different metallic and semiconductive substrates (aluminium, platinum, silver, gold, tin-cooper alloy, indium-tin-oxide, stainless steel, and copper), indicate that the substrate influences its porous features but not its absorbance characteristics. The platinum black exhibited a broad absorbance and low reflectance in the ultraviolet, visible, and infrared regions. These characteristics make this material suitable for use as a high-temperature resistant absorber layer for the fabrication of microelectronics.

  18. Effect of Black Rice Powder Levels on Quality Properties of Emulsion-type Sausage

    PubMed Central

    2016-01-01

    The effects of black rice powder on the quality of sausage were investigated. Samples were prepared with 0% (control), 1%, 3%, and 5% black rice powder. With increasing black rice powder content, the moisture and ash content of sausage increased, while protein content was significantly less than that observed for the control (p<0.05). The fat content in samples containing 5% black rice powder was significantly less than that observed for other samples (p<0.05). With increasing black rice powder content, the pH of uncooked and cooked samples increased. In addition, lightness, redness, and yellowness decreased. With increasing content of black rice powder, emulsion stability decreased. On the other hand, with increasing black rice powder content, cooking yield increased. As compared to the other samples, those containing high content of black rice powder exhibited higher viscosity. With increasing black rice powder content, the hardness of samples decreased, while the gumminess and chewiness of samples containing black rice powder were less than those observed for the control (p<0.05). Moreover, with increasing black rice powder content, the flavor, juiciness, and overall acceptability of samples increased. In addition, the tenderness of samples containing 3% and 5% black rice powder was significantly greater than that observed for the control and sample containing 1% black rice powder (p<0.05). In addition to the economic benefits, black rice powder can be used to improve quality characteristics. PMID:28115884

  19. 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

  20. Black Hole Spills Kaleidoscope of Color

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This new false-colored image from NASA's Hubble, Chandra and Spitzer space telescopes shows a giant jet of particles that has been shot out from the vicinity of a type of supermassive black hole called a quasar. The jet is enormous, stretching across more than 100,000 light-years of space -- a size comparable to our own Milky Way galaxy!

    Quasars are among the brightest objects in the universe. They consist of supermassive black holes surrounded by turbulent material, which is being heated up as it is dragged toward the black hole. This hot material glows brilliantly, and some of it gets blown off into space in the form of powerful jets.

    The jet pictured here is streaming out from the first known quasar, called 3C273, discovered in 1963. A kaleidoscope of colors represents the jet's assorted light waves. X-rays, the highest-energy light in the image, are shown at the far left in blue (the black hole itself is well to the left of the image). The X-rays were captured by Chandra. As you move from left to right, the light diminishes in energy, and wavelengths increase in size. Visible light recorded by Hubble is displayed in green, while infrared light caught by Spitzer is red. Areas where visible and infrared light overlap appear yellow.

  1. Black Hole Spills Kaleidoscope of Color

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This new false-colored image from NASA's Hubble, Chandra and Spitzer space telescopes shows a giant jet of particles that has been shot out from the vicinity of a type of supermassive black hole called a quasar. The jet is enormous, stretching across more than 100,000 light-years of space -- a size comparable to our own Milky Way galaxy!

    Quasars are among the brightest objects in the universe. They consist of supermassive black holes surrounded by turbulent material, which is being heated up as it is dragged toward the black hole. This hot material glows brilliantly, and some of it gets blown off into space in the form of powerful jets.

    The jet pictured here is streaming out from the first known quasar, called 3C273, discovered in 1963. A kaleidoscope of colors represents the jet's assorted light waves. X-rays, the highest-energy light in the image, are shown at the far left in blue (the black hole itself is well to the left of the image). The X-rays were captured by Chandra. As you move from left to right, the light diminishes in energy, and wavelengths increase in size. Visible light recorded by Hubble is displayed in green, while infrared light caught by Spitzer is red. Areas where visible and infrared light overlap appear yellow.

  2. Hard Work and Hard Data: Getting Our Message Out.

    ERIC Educational Resources Information Center

    Glau, Gregory R.

    Unless questions about student performance and student retention can be answered and unless educators are proactive in finding and publicizing such information, basic writing programs cannot determine if what they are doing is working. Hard data, especially from underrepresented groups, is needed to support these programs. At Arizona State…

  3. Magnetic levitation for hard superconductors

    SciTech Connect

    Kordyuk, A.A.

    1998-01-01

    An approach for calculating the interaction between a hard superconductor and a permanent magnet in the field-cooled case is proposed. The exact solutions were obtained for the point magnetic dipole over a flat ideally hard superconductor. We have shown that such an approach is adaptable to a wide practical range of melt-textured high-temperature superconductors{close_quote} systems with magnetic levitation. In this case, the energy losses can be calculated from the alternating magnetic field distribution on the superconducting sample surface. {copyright} {ital 1998 American Institute of Physics.}

  4. Future hard disk drive systems

    NASA Astrophysics Data System (ADS)

    Wood, Roger

    2009-03-01

    This paper briefly reviews the evolution of today's hard disk drive with the additional intention of orienting the reader to the overall mechanical and electrical architecture. The modern hard disk drive is a miracle of storage capacity and function together with remarkable economy of design. This paper presents a personal view of future customer requirements and the anticipated design evolution of the components. There are critical decisions and great challenges ahead for the key technologies of heads, media, head-disk interface, mechanics, and electronics.

  5. Polarized synchrotron emission in quiescent black hole X-ray transients

    NASA Astrophysics Data System (ADS)

    Russell, David M.; Shahbaz, Tariq; Lewis, Fraser; Gallo, Elena

    2016-12-01

    We present near-infrared polarimetric observations of the black hole X-ray binaries Swift J1357.2-0933 and A0620-00. In both sources, recent studies have demonstrated the presence of variable infrared synchrotron emission in quiescence, most likely from weak compact jets. For Swift J1357.2-0933, we find that the synchrotron emission is polarized at a level of 8.0 ± 2.5 per cent (a 3.2σ detection of intrinsic polarization). The mean magnitude and rms variability of the flux (fractional rms of 19-24 per cent in KS band) agree with previous observations. These properties imply a continuously launched (stable on long time-scales), highly variable (on short time-scales) jet in the Swift J1357.2-0933 system in quiescence, which has a moderately tangled magnetic field close to the base of the jet. We find that for A0620-00, there are likely to be three components to the optical-infrared polarization; interstellar dust along the line of sight, scattering within the system, and an additional source that changes the polarization position angle in the reddest (H and KS) wavebands. We interpret this as a stronger contribution of synchrotron emission, and by subtracting the line-of-sight polarization, we measure an excess of ˜1.25 ± 0.28 per cent polarization and a position angle of the magnetic field vector that is consistent with being parallel with the axis of the resolved radio jet. These results imply that weak jets in low-luminosity accreting systems have magnetic fields which possess similarly tangled fields compared to the more luminous, hard state jets in X-ray binaries.

  6. Infrared emission from tidal disruption events - probing the pc-scale dust content around galactic nuclei

    NASA Astrophysics Data System (ADS)

    Lu, Wenbin; Kumar, Pawan; Evans, Neal J.

    2016-05-01

    Recent UV-optical surveys have been successful in finding tidal disruption events (TDEs), in which a star is tidally disrupted by a supermassive black hole (BH). These TDEs release a huge amount of radiation energy Erad ˜ 1051-1052 erg into the circum-nuclear medium. If the medium is dusty, most of the radiation energy will be absorbed by dust grains within ˜1 pc from the BH and re-radiated in the infrared. We calculate the dust emission light curve from a 1D radiative transfer model, taking into account the time-dependent heating, cooling and sublimation of dust grains. We show that the dust emission peaks at 3-10 μm and has typical luminosities between 1042 and 1043 erg s-1 (with sky covering factor of dusty clouds ranging from 0.1 to 1). This is detectable by current generation of telescopes. In the near future, James Webb Space Telescope will be able to perform photometric and spectroscopic measurements, in which silicate or polycyclic aromatic hydrocarbon features may be found. Dust grains are non-spherical and may be aligned with the magnetic field, so the dust emission may be significantly polarized. Observations at rest-frame wavelength ≥ 2 μm have only been reported from two TDE candidates, SDSS J0952+2143 and SwiftJ1644+57. Although consistent with the dust emission from TDEs, the mid-infrared fluxes of the two events may be from other sources. Long-term monitoring is needed to draw a firm conclusion. We also point out two nearby TDE candidates (ASASSN-14ae and -14li) where the dust emission may be currently detectable. Detection of dust infrared emission from TDEs would provide information regarding the dust content and its distribution in the central pc of non-active galactic nuclei, which is hard to probe otherwise.

  7. Dynamic indentation hardness of materials

    NASA Astrophysics Data System (ADS)

    Koeppel, Brian James

    Indentation hardness is one of the simplest and most commonly used measures for quickly characterizing material response under static loads. Hardness may mean resistance to cutting to a machinist, resistance to wear to a tribologist, or a measure of flow stress to a design engineer. In this simple technique, a predetermined force is applied to an indenter for 5-30 seconds causing it to penetrate a specimen. By measuring the load and the indentation size, a hardness value is determined. However, the rate of deformation during indenter penetration is of the order of 10sp{-4}\\ ssp{-1}. In most practical applications, such as high speed machining or impact, material deforms at strain rates in excess of 10sp3{-}10sp5\\ ssp{-1}. At such high rates, it is well established that the plastic behavior of materials is considerably different from their static counterpart. For example, materials exhibit an increase in their yield stress, flow stress, fracture stress, and fracture toughness at high strain rates. Hence, the use of static hardness as an indicator of material response under dynamic loads may not be appropriate. Accordingly, a simple dynamic indentation hardness tester is developed for characterizing materials at strain rates similar to those encountered in realistic situations. The experimental technique uses elastic stress wave propagation phenomena in a slender rod. The technique is designed to deliver a single indentation load of 100-200 mus duration. Similar to static measurements, the dynamic hardness is determined from the measured load and indentation size. Hardness measurements on a range of metals have revealed that the dynamic hardness is consistently greater than the static hardness. The increase in hardness is strongly dependent on the crystal structure of the material. The observed trends in hardness are also found to be consistent with the yield and flow stresses of these materials under uniaxial compression. Therefore, it is suggested that the

  8. The Smallest Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Greene, Jenny

    2012-03-01

    I discuss our ongoing efforts to search for the smallest supermassive black holes (BHs) with masses of 10^4-10^6 Msun. The number density and location of these enigmatic sources provide some of our only observational constraints on the first primordial seed BHs. Merging BHs in this mass range are expected to be strong gravitational wave sources. Finally, since these BHs live in very different environments from their more massive cousins, they allow us to study the interactions between BHs and galaxies in a new way. Unfortunately, low-mass BHs are hard to find. I will discuss the known BHs in this mass regime and the path forward to a definitive understanding of the population.

  9. The Hard X-ray Variability of the LMC X-1 system

    NASA Astrophysics Data System (ADS)

    Grefenstette, Brian; Fuerst, Felix; Miller, Jon M.; Nowak, Michael; Smith, David M.; Tomsick, John; Walton, Dom; Wilms, Joern; Bachetti, Matteo

    2017-08-01

    Only two parameters are needed to completely describe the physics of a black hole: its mass and its spin. This is true for both stellar mass black holes as well as for the supermassive black holes that reside in the centers of most galaxies. While these two parameters are fundamental to our understanding of black holes, accurately measuring the spin of a black hole is a challenge in modern astrophysics and many spins of black hole systems are only measurable when the system goes into outburst and the luminosity increases to nearly the Eddington limit from quiescence (˜1e-6 Eddington). Persistently accreting systems, in contrast, should instead allow to probe accretion physics in a more steady-state accretion mode. We report on NuSTAR and XMM observations of the persistent wind-fed black hole binary LMC X-1, which is a moderately accreting (10% Eddington) system. Over two NuSTAR epochs and one joint NuSTAR-XMM observations we find significant variation in the hardness and intensity of the source as well as an X-ray flare observed by both XMM and NusTAR. The variability of the source impacts the measurement of the spin of the black hole and the interpretation of the X-ray spectrum. We will discuss our findings, and the implications of these results.

  10. Performance evaluation of an infrared thermocouple.

    PubMed

    Chen, Chiachung; Weng, Yu-Kai; Shen, Te-Ching

    2010-01-01

    The measurement of the leaf temperature of forests or agricultural plants is an important technique for the monitoring of the physiological state of crops. The infrared thermometer is a convenient device due to its fast response and nondestructive measurement technique. Nowadays, a novel infrared thermocouple, developed with the same measurement principle of the infrared thermometer but using a different detector, has been commercialized for non-contact temperature measurement. The performances of two-kinds of infrared thermocouples were evaluated in this study. The standard temperature was maintained by a temperature calibrator and a special black cavity device. The results indicated that both types of infrared thermocouples had good precision. The error distribution ranged from -1.8 °C to 18 °C as the reading values served as the true values. Within the range from 13 °C to 37 °C, the adequate calibration equations were the high-order polynomial equations. Within the narrower range from 20 °C to 35 °C, the adequate equation was a linear equation for one sensor and a two-order polynomial equation for the other sensor. The accuracy of the two kinds of infrared thermocouple was improved by nearly 0.4 °C with the calibration equations. These devices could serve as mobile monitoring tools for in situ and real time routine estimation of leaf temperatures.

  11. Performance Evaluation of an Infrared Thermocouple

    PubMed Central

    Chen, Chiachung; Weng, Yu-Kai; Shen, Te-Ching

    2010-01-01

    The measurement of the leaf temperature of forests or agricultural plants is an important technique for the monitoring of the physiological state of crops. The infrared thermometer is a convenient device due to its fast response and nondestructive measurement technique. Nowadays, a novel infrared thermocouple, developed with the same measurement principle of the infrared thermometer but using a different detector, has been commercialized for non-contact temperature measurement. The performances of two-kinds of infrared thermocouples were evaluated in this study. The standard temperature was maintained by a temperature calibrator and a special black cavity device. The results indicated that both types of infrared thermocouples had good precision. The error distribution ranged from −1.8 °C to 18 °C as the reading values served as the true values. Within the range from 13 °C to 37 °C, the adequate calibration equations were the high-order polynomial equations. Within the narrower range from 20 °C to 35 °C, the adequate equation was a linear equation for one sensor and a two-order polynomial equation for the other sensor. The accuracy of the two kinds of infrared thermocouple was improved by nearly 0.4 °C with the calibration equations. These devices could serve as mobile monitoring tools for in situ and real time routine estimation of leaf temperatures. PMID:22163458

  12. Hard Trying and These Recipes

    ERIC Educational Resources Information Center

    Atwell, Nancie

    2003-01-01

    Writers thrive when they are motivated to work hard, have regular opportunities to practice and reflect, and benefit from a knowledgeable teacher who knows writing. Student feedback to lessons during writing workshop helped guide Nancie Atwell in her quest to provide the richest and most efficient path to better writing.

  13. Playing the Numbers: Hard Choices

    ERIC Educational Resources Information Center

    Doyle, William R.

    2009-01-01

    Stateline.org recently called this recession the worst in 50 years for state budgets. As has been the case in past economic downturns, higher education looks to be particularly hard hit. Funds from the American Recovery and Relief Act may have postponed some of the difficulty for many colleges and universities, but the outlook for public higher…

  14. Metrics for Hard Goods Merchandising.

    ERIC Educational Resources Information Center

    Cooper, Gloria S., Ed.; Magisos, Joel H., Ed.

    Designed to meet the job-related metric measurement needs of students interested in hard goods merchandising, this instructional package is one of five for the marketing and distribution cluster, part of a set of 55 packages for metric instruction in different occupations. The package is intended for students who already know the occupational…

  15. Hard Knocks in Tyrrhena Terra

    NASA Image and Video Library

    2017-02-02

    NASA Mars Reconnaissance Orbiter observed a small portion of a dark crater floor in the Tyrrhena Terra region of Mars. This is largely ancient hard bedrock that has been cratered by numerous impacts over the eons. http://photojournal.jpl.nasa.gov/catalog/PIA11179

  16. FATIGUE OF BIOMATERIALS: HARD TISSUES

    PubMed Central

    Arola, D.; Bajaj, D.; Ivancik, J.; Majd, H.; Zhang, D.

    2009-01-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions. PMID:20563239

  17. "We, the Black Americans"

    ERIC Educational Resources Information Center

    Federal Aid Planner, 1972

    1972-01-01

    Information gathered during the 1970 census reports on the changing economic and social conditions of U. S. blacks. Comparative data for blacks and whites is provided covering income, education, voter participation, housing, life style, and residence location. (Author/DN)

  18. Counseling Black Adolescent Parents

    ERIC Educational Resources Information Center

    Gilbert, Gwendolyn C.

    1974-01-01

    Black adolescent parents need counsel from social workers who are able to intervene with a discerning knowledge of concepts, such as neocolonialism, survival, and liberation, that are important to them and to the black community. (Author)

  19. Black widow spider (image)

    MedlinePlus

    This is a black widow spider. Note the red "hour glass" on the abdomen. The bite of the black widow can produce severe symptoms but is seldom fatal, except in young children and older adults. (Image courtesy ...

  20. NASA Now: Black Holes

    NASA Image and Video Library

    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...

  1. Black hole hair removal

    NASA Astrophysics Data System (ADS)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-07-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair — degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  2. Empowering Rhetoric: Black Students Writing Black Panthers.

    ERIC Educational Resources Information Center

    Pough, Gwendolyn D.

    2002-01-01

    Examines Black student responses to Black Panther Party documents and how those documents moved the students toward change. Maintains that by allowing the classroom to function as a public space which students can discuss the issues that matter to them, teachers can help to foster and encourage student activism and ultimately their empowerment.…

  3. Patterning of oxide-hardened gold black by photolithography and metal lift-off

    Treesearch

    Deep Panjwani; Mehmet Yesiltas; Janardan Nath; D.E. Maukonen; Imen Rezadad; Evan M. Smith; R.E. Peale; Carol Hirschmugl; Julia Sedlmair; Ralf Wehlitz; Miriam Unger; Glenn Boreman

    2014-01-01

    A method to pattern infrared-absorbing gold black by conventional photolithography and lift-off is described. A photo-resist pattern is developed on a substrate by standard photolithography. Gold black is deposited over the whole by thermal evaporation in an inert gas at

  4. No-go theorem for slowly rotating black holes in Hořava-Lifshitz gravity.

    PubMed

    Barausse, Enrico; Sotiriou, Thomas P

    2012-11-02

    We consider slowly rotating, stationary, axisymmetric black holes in the infrared limit of Hořava-Lifshitz gravity. We show that such solutions do not exist, provided that they are regular everywhere apart from the central singularity. This has profound implications for the viability of the theory, considering the astrophysical evidence for the existence of black holes with nonzero spin.

  5. HUBBLE'S INFRARED GALAXY GALLERY

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Astronomers have used the NASA Hubble Space Telescope to produce an infrared 'photo essay' of spiral galaxies. By penetrating the dust clouds swirling around the centers of these galaxies, the telescope's infrared vision is offering fresh views of star birth. These six images, taken with the Near Infrared Camera and Multi-Object Spectrometer, showcase different views of spiral galaxies, from a face-on image of an entire galaxy to a close-up of a core. The top row shows spirals at diverse angles, from face-on, (left); to slightly tilted, (center); to edge-on, (right). The bottom row shows close-ups of the hubs of three galaxies. In these images, red corresponds to glowing hydrogen, the raw material for star birth. The red knots outlining the curving spiral arms in NGC 5653 and NGC 3593, for example, pinpoint rich star-forming regions where the surrounding hydrogen gas is heated by intense ultraviolet radiation from young, massive stars. In visible light, many of these regions can be hidden from view by the clouds of gas and dust in which they were born. The glowing hydrogen found inside the cores of these galaxies, as in NGC 6946, may be due to star birth; radiation from active galactic nuclei (AGN), which are powered by massive black holes; or a combination of both. White is light from middle-age stars. Clusters of stars appear as white dots, as in NGC 2903. The galaxy cores are mostly white because of their dense concentration of stars. The dark material seen in these images is dust. These galaxies are part of a Hubble census of about 100 spiral galaxies. Astronomers at Space Telescope Science Institute took these images to fill gaps in the scheduling of a campaign using the NICMOS-3 camera. The data were non-proprietary, and were made available to the entire astronomical community. Filters: Three filters were used: red, blue, and green. Red represents emission at the Paschen Alpha line (light from glowing hydrogen) at a wavelength of 1.87 microns. Blue shows the

  6. HUBBLE'S INFRARED GALAXY GALLERY

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Astronomers have used the NASA Hubble Space Telescope to produce an infrared 'photo essay' of spiral galaxies. By penetrating the dust clouds swirling around the centers of these galaxies, the telescope's infrared vision is offering fresh views of star birth. These six images, taken with the Near Infrared Camera and Multi-Object Spectrometer, showcase different views of spiral galaxies, from a face-on image of an entire galaxy to a close-up of a core. The top row shows spirals at diverse angles, from face-on, (left); to slightly tilted, (center); to edge-on, (right). The bottom row shows close-ups of the hubs of three galaxies. In these images, red corresponds to glowing hydrogen, the raw material for star birth. The red knots outlining the curving spiral arms in NGC 5653 and NGC 3593, for example, pinpoint rich star-forming regions where the surrounding hydrogen gas is heated by intense ultraviolet radiation from young, massive stars. In visible light, many of these regions can be hidden from view by the clouds of gas and dust in which they were born. The glowing hydrogen found inside the cores of these galaxies, as in NGC 6946, may be due to star birth; radiation from active galactic nuclei (AGN), which are powered by massive black holes; or a combination of both. White is light from middle-age stars. Clusters of stars appear as white dots, as in NGC 2903. The galaxy cores are mostly white because of their dense concentration of stars. The dark material seen in these images is dust. These galaxies are part of a Hubble census of about 100 spiral galaxies. Astronomers at Space Telescope Science Institute took these images to fill gaps in the scheduling of a campaign using the NICMOS-3 camera. The data were non-proprietary, and were made available to the entire astronomical community. Filters: Three filters were used: red, blue, and green. Red represents emission at the Paschen Alpha line (light from glowing hydrogen) at a wavelength of 1.87 microns. Blue shows the

  7. Hard processes in hadronic interactions

    SciTech Connect

    Satz, H. |; Wang, X.N.

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason - and in fact its original trigger - is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, we discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behaviour it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time and work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERn in Geneva andin July 1994 at LBL in Berkeley.

  8. Hard processes in hadronic interactions

    SciTech Connect

    Satz, H. |; Wang, X.N.

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason--and in fact its original trigger--is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, the authors discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behavior it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time to work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERN in Geneva and in July 1994 at LBL in Berkeley. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  9. Black Hole Thermodynamics

    NASA Astrophysics Data System (ADS)

    Israel, Werner

    This chapter reviews the conceptual developments on black hole thermodynamics and the attempts to determine the origin of black hole entropy in terms of their horizon area. The brick wall model and an operational approach are discussed. An attempt to understand at the microlevel how the quantum black hole acquires its thermal properties is included. The chapter concludes with some remarks on the extension of these techniques to describing the dynamical process of black hole evaporation.

  10. 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.

  11. Hard X-Ray Emission of X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, P.

    1999-01-01

    The primary goal of this proposal was to perform an accurate measurement of the broadband x-ray spectrum of a neutron-star low-mass x-ray binary found in a hard x-ray state. This goal was accomplished using data obtained under another proposal, which has provided exciting new information on the hard x-ray emission of neutron-star low-mass x-ray binaries. In "BeppoSAX Observations of the Atoll X-Ray Binary 4U0614+091", we present our analysis of the spectrum of 4U0614+091 over the energy band from 0.3-150 keV. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220 keV, or as a non-thermal powerlaw. Such a very hard x-ray spectrum has not been previously seen from neutron-star low-mass x-ray binaries. We also detected a spectral feature that can be interpreted as reprocessing, via Compton reflection, of the direct emission by an optically-thick disk and found a correlation between the photon index of the power-law tail and the fraction of radiation reflected which is similar to the correlation found for black hole candidate x-ray binaries and Seyfert galaxies. A secondary goal was to measure the timing properties of the x-ray emission from neutronstar low-mass x-ray binaries in their low/hard states.

  12. Black Carbon Measurement and Modeling in the Arabian Peninsula

    NASA Astrophysics Data System (ADS)

    Zawad, Faisal Al; Khoder, Mamdouh; Almazroui, Mansour; Alghamdi, Mansour; Lihavainen, Heikki; Hyvarinen, Antti; Henriksson, Svante

    2017-04-01

    Black carbon is an important atmospheric aerosol as an effective factor in public health, changing the global and regional climate, and reducing visibility. Black carbon absorbs light, warms the atmosphere, and modifies cloud droplets and the amount of precipitation. In spite of this significance, knowledge of black carbon over the Arabian Peninsula is hard to find in literature until recently. The total mass of black carbon and wind direction and speeds were measured continuously at Hada Al-Sham, Saudi Arabia for the year 2013. In addition, a state of the art global aerosol - climate model (ECHAM5-HAM) was used to determine black carbon climatology over the Arabian Peninsula. Simulation of the model was carried out for the years eight years (2004 - 2011). The daily mean values of the concentrations of black carbon had a minimum of 15.0 ng/m3 and a maximum of 6372 ng/m3 with a mean of at 1899 ng/m3. The diurnal pattern of black carbon showed higher values overnight, and steady low values during daytimes caused by sea and land breezes. Seasons of black carbon vary over the Arabian Peninsula, and the longest is in the Northern Region where it lasts from July to October. High concentrations of black carbon at Hada Al-Sham was observed with a mean of 1.9 µm/m3, and seasons of black carbon vary widely across the Arabian Peninsula. Assessment of the effects of black carbon over the Arabian Peninsula on the global radiation balance. Initiating a black carbon monitoring network is highly recommended to assess its impacts on health, environment, and climate.

  13. Black Studies Perspectives

    ERIC Educational Resources Information Center

    Adams, Russell L.

    1977-01-01

    Discusses the proposition that the black studies movement is but a continuing aspect of our general battle for survival and liberation in a fluctuatingly hostile environment, and that a part of what is seen today in the black studies movement is but a fluctuation in a fight and an expression of black collective awareness dating back to the…

  14. To Liberate Black Actors.

    ERIC Educational Resources Information Center

    Riley, Clayton

    1983-01-01

    Three things will help to change American theater's unsatisfactory climate for Blacks and its growing mediocrity: (1) an end to the cultural dependence on British theater; (2) an examination of America's racial history in "White" as well as "Black" productions; and (3) abandonment of the notion that Blacks and Whites can flourish in isolation from…

  15. The Black Experience.

    ERIC Educational Resources Information Center

    Allen, Lee E., Ed.

    1974-01-01

    This issue of "The Leaflet" focuses on the black experience. Included are four poems by Lawrence Johnson, "Little Girl Black,""Be's That Way Sometime,""My Blackness," and "Three Songs of Freedom"; two papers originally presented at the 1973 New England Association of Teachers of English Conference, "Teaching English to the Disadvantaged in Large…

  16. Genocide and Black Ecology

    ERIC Educational Resources Information Center

    Sinnette, Calvin H.

    1972-01-01

    Contends that the survival of black people is in serious jeopardy as is evidenced in contemporary discussions on the worldwide plight of black people, and that an exhaustive study of the problem in its many dimensions is seriously lacking; the moral and ethical issues of genocide require examination from a black perspective. (JW)

  17. Asymmetric Black Diholes

    SciTech Connect

    Manko, V. S.; Sanchez-Mondragon, J.; Ruiz, E.

    2009-05-01

    In the present paper we enlarge the list of black dihole spacetimes by introducing the notion of asymmetric black diholes which describe configurations composed of two static charged black holes endowed with unequal masses and equal but opposite charges. The asymmetric dihole solutions are considered both in the Einstein-Maxwell and Einstein-Maxwell-dilaton theories.

  18. The Black Woman.

    ERIC Educational Resources Information Center

    Browne, Juanita M.

    The Black woman has been the transmitter of culture in the black community. Two of the important roles of African women were perpetuated during slavery and continue until today. They are her role in economic endeavor and her close bond with her children. The woman in African society was additionally politically significant. The black woman has…

  19. Black Veterans Return

    ERIC Educational Resources Information Center

    Fendrich, James; Pearson, Michael

    1970-01-01

    This is a survey study of black veterans' attitudes toward white authorities, the "law and order controversy, racial separatism, violence, and black identification. Results of the survey are held to suggest that alienation will move a substantial proportion of these veterans into the black radical movement. (KG)

  20. 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.

  1. Hard X-Ray-selected AGNs in Low-mass Galaxies from the NuSTAR Serendipitous Survey

    NASA Astrophysics Data System (ADS)

    Chen, C.-T. J.; Brandt, W. N.; Reines, A. E.; Lansbury, G.; Stern, D.; Alexander, D. M.; Bauer, F.; Del Moro, A.; Gandhi, P.; Harrison, F. A.; Hickox, R. C.; Koss, M. J.; Lanz, L.; Luo, B.; Mullaney, J. R.; Ricci, C.; Trump, J. R.

    2017-03-01

    We present a sample of 10 low-mass active galactic nuclei (AGNs) selected from the 40-month Nuclear Spectroscopic Telescope Array (NuSTAR) serendipitous survey. The sample is selected to have robust NuSTAR detections at 3{--}24 {keV}, to be at z< 0.3, and to have optical r-band magnitudes at least 0.5 mag fainter than an {L}\\star galaxy at its redshift. The median values of absolute magnitude, stellar mass, and 2–10 X-ray luminosity of our sample are < {M}r> =-20.03, < {M}\\star > =4.6× {10}9 {M}ȯ , and < {L}2-10{keV}> =3.1× {10}42 erg s‑1, respectively. Five objects have detectable broad Hα emission in their optical spectra, indicating black hole masses of (1.1{--}10.4)× {10}6 {M}ȯ . We find that {30}-10+17 % of the galaxies in our sample do not show AGN-like optical narrow emission lines, and one of the 10 galaxies in our sample, J115851+4243.2, shows evidence for heavy X-ray absorption. This result implies that a non-negligible fraction of low-mass galaxies might harbor accreting massive black holes that are missed by optical spectroscopic surveys and < 10 {keV} X-ray surveys. The mid-IR colors of our sample also indicate that these optically normal low-mass AGNs cannot be efficiently identified with typical AGN selection criteria based on Wide Field Infrared Survey Explorer colors. While the hard (> 10 keV) X-ray-selected low-mass AGN sample size is still limited, our results show that sensitive NuSTAR observations are capable of probing faint hard X-ray emission originating from the nuclei of low-mass galaxies out to moderate redshift (z< 0.3), thus providing a critical step in understanding AGN demographics in low-mass galaxies.

  2. Fourier Transform Infrared Spectroscopic Studies Of Wheat In The Mid Infrared

    NASA Astrophysics Data System (ADS)

    Olinger, Jill M.; Griffiths, Peter R.

    1989-12-01

    Official grain standards of the United States state that wheat may be divided into seven classes which are: Durum, Red Durum, Hard Red Spring, Hard Red Winter, Soft Red Winter, White, and Mixed.1 Most end uses of wheat involve converting the grain into flour through one of a variety of grinding methods. The quality of wheat-based products is often very dependent upon the type or class of wheat which was used to make the flour. Pasta products, for example, are made almost exclusively from the flour of durum wheats, which are the hardest of the wheats listed above. The highest quality breads are produced using flour from wheats classed as hard, whereas cakes, cookies and pastries are considered best when flour from wheats classed as soft are used. It is obvious then that the capability of determining the class of a particular wheat, especially with respect to hardness, is of economic importance to growers, processors, and merchants of wheat and wheat products. Hardness has been measured in many different ways 2-5 but, as of yet, no one method has become the method of choice. This paper reports on the use of principal components analysis (PCA) of mid infrared diffuse reflectance (DR) spectra of diluted ground wheats to aid in the classification of those wheats with respect to their hardness. The theory and mathematics involved in a principal component analysis have been described elsewhere.9

  3. THE CHANDRA VIEW OF NGC 4178: THE LOWEST MASS BLACK HOLE IN A BULGELESS DISK GALAXY?

    SciTech Connect

    Secrest, N. J.; Satyapal, S.; Gliozzi, M.; Cheung, C. C.; Seth, A. C.; Boeker, T.

    2012-07-01

    Using high-resolution Chandra data, we report the presence of a weak X-ray point source coincident with the nucleus of NGC 4178, a late-type bulgeless disk galaxy known to have high-ionization mid-infrared (mid-IR) lines typically associated with active galactic nuclei (AGNs). Although the faintness of this source precludes a direct spectral analysis, we are able to infer its basic spectral properties using hardness ratios. X-ray modeling, combined with the nuclear mid-IR characteristics, suggests that NGC 4178 may host a highly absorbed AGN accreting at a high rate with a bolometric luminosity on order of 10{sup 43} erg s{sup -1}. The black hole mass estimate, based on our Chandra data and archival Very Large Array data using the most recent fundamental plane relations, is {approx}10{sup 4}-10{sup 5} M{sub Sun }, possibly the lowest mass nuclear black hole currently known. There are also three off-nuclear sources, two with a similar brightness to the nuclear source at 36'' and 32'' from the center. As with the nuclear source, hardness ratios are used to estimate spectra for these two sources, and both are consistent with a simple power-law (PL) model with absorption. These two sources have X-ray luminosities of the order of {approx}10{sup 38} erg s{sup -1}, which place them at the threshold between X-ray binaries and ultraluminous X-ray sources (ULXs). The third off-nuclear source, located 49'' from the center, is the brightest source detected, with an X-ray luminosity of {approx}10{sup 40} erg s{sup -1}. Its spectrum is well fit with an absorbed PL model, suggesting that it is a ULX. We also fit its spectrum with the Bulk Motion Comptonization model and suggest that this source is consistent with an intermediate-mass black hole of mass (6 {+-} 2) Multiplication-Sign 10{sup 3} M{sub Sun }.

  4. Disc-jet Coupling in the 2009 Outburst of the Black Hole Candidate H1743-322

    NASA Technical Reports Server (NTRS)

    Miller-Jones, J. C. A.; Sivakoff, G. R.; Altamirano, D.; Coriat, M.; Corbel, S.; Dhawan, V.; Krimm, H. A.; Remillard, R. A.; Rupen, M. P.; Russell, D. M.; Fender, R. P.; Heinz, S.; Kording, E. G.; Maitra, D.; Markoff, S.; Migliari, S.; Sarazin, C. L.; Tudose, V.

    2012-01-01

    We present an intensive radio and X-ray monitoring campaign on the 2009 outburst of the Galactic black hole candidate X-ray binary H1743-322. With the high angular resolution of the Very Long Baseline Array, we resolve the jet ejection event and measure the proper motions of the jet ejecta relative to the position of the compact core jets detected at the beginning of the outburst. This allows us to accurately couple the moment when the jet ejection event occurred with X-ray spectral and timing signatures. We find that X-ray timing signatures are the best diagnostic of the jet ejection event in this outburst, which occurred as the X-ray variability began to decrease and the Type C quasi-periodic oscillations disappeared from the X-ray power density spectrum. However, this sequence of events does not appear to be replicated in all black hole X-ray binary outbursts, even within an individual source. In our observations of H1743-322, the ejection was contemporaneous with a quenching of the radio emission, prior to the start of the major radio flare. This contradicts previous assumptions that the onset of the radio flare marks the moment of ejection. The jet speed appears to vary between outbursts with a positive correlation outburst luminosity. The compact core radio jet reactivated on transition to the hard intermediate state at the end of the outburst and not when the source reached the low hard spectral state. Comparison with the known near-infrared behaviour of the compact jets suggests a gradual evolution of the compact jet power over a few days near beginning the and end of an outburst

  5. Disentangling the NIR/optical emission of the black hole XTE J1650-500 during outburst

    NASA Astrophysics Data System (ADS)

    Curran, P. A.; Chaty, S.; Zurita Heras, J. A.

    2012-11-01

    Context. While the sources of X-ray and radio emission in the different states of low-mass X-ray binaries are relatively well understood, the origin of the near-infrared (NIR) and optical emission is more often debated. It is likely that the NIR/optical flux originates from an amalgam of different emission regions, because it occurs at the intersecting wavelengths of multiple processes. Aims: We aim to identify the NIR/optical emission region(s) of one such low-mass X-ray binary and black hole candidate, XTE J1650-500, via photometric, timing, and spectral analyses. Methods: We present unique NIR/optical images and spectra, obtained with the ESO-New Technology Telescope, during the peak of the 2001 outburst of XTE J1650-500. Results: The data suggest that the NIR/optical flux is due to a combination of emission mechanisms including a significant contribution from X-ray reprocessing and, at early times in the hard state, a relativistic jet that is NIR/radio dim compared to similar sources. Conclusions: The jet of XTE J1650-500 is relatively weak compared to that of other black hole low-mass X-ray binaries, possibly because we observe as it is being "turned off" or quenched at the state transition. While there are several outliers to the radio-X-ray correlation of the hard state of low-mass X-ray binaries, XTE J1650-500 is the first example of an outlier to the NIR/optical-X-ray correlation. Based on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility.

  6. 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.

  7. Black Male-Black Female Relationships: The Perceptions of 155 Middle-Class Black Men.

    ERIC Educational Resources Information Center

    Cazenave, Noel A.

    1983-01-01

    Surveyed middle-class Black men (N=155) concerning their perceptions of Black male-female relationships. A majority reported that Black women had more opportunity than Black men; a large minority felt that Black women were partly responsible for the relative low status of Black men. Most preferred traditional gender roles. (WAS)

  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. Molecular hardness and softness, local hardness and softness, hardness and softness kernels, and relations among these quantities

    NASA Astrophysics Data System (ADS)

    Berkowitz, Max; Parr, Robert G.

    1988-02-01

    Hardness and softness kernels η(r,r') and s(r,r') are defined for the ground state of an atomic or molecular electronic system, and the previously defined local hardness and softness η(r) and s(r) and global hardness and softness η and S are obtained from them. The physical meaning of s(r), as a charge capacitance, is discussed (following Huheey and Politzer), and two alternative ``hardness'' indices are identified and briefly discussed.

  10. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, M.S.; Schuster, G.J.; Skorpik, J.R.

    1997-07-08

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part. 12 figs.

  11. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, Morris S.; Schuster, George J.; Skorpik, James R.

    1997-01-01

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part.

  12. Transpecific microsatellites for hard pines.

    PubMed

    Shepherd, M.; Cross, M.; Maguire, L.; Dieters, J.; Williams, G.; Henry, J.

    2002-04-01

    Microsatellites are difficult to recover from large plant genomes so cross-specific utilisation is an important source of markers. Fifty microsatellites were tested for cross-specific amplification and polymorphism to two New World hard pine species, slash pine ( Pinus elliottii var. elliottii) and Caribbean pine ( P. caribaea var. hondurensis). Twenty-nine (58%) markers amplified in both hard pine species, and 23 of these 29 were polymorphic. Soft pine (subgenus Strobus) microsatellite markers did amplify, but none were polymorphic. Pinus elliottii var. elliottii and P. caribaea var. hondurensis showed mutational changes in the flanking regions and the repeat motif that were informative for Pinus spp. phylogenetic relationships. Most allele length variation could be attributed to variability in repeat unit number. There was no evidence for ascertainment bias.

  13. Use of archive aerial photography for monitoring black mangrove populations

    USDA-ARS?s Scientific Manuscript database

    A study was conducted on the south Texas Gulf Coast to evaluate archive aerial color-infrared (CIR) photography combined with supervised image analysis techniques to quantify changes in black mangrove [Avicennia germinans (L.) L.] populations over a 26-year period. Archive CIR film from two study si...

  14. Microwave assisted hard rock cutting

    DOEpatents

    Lindroth, David P.; Morrell, Roger J.; Blair, James R.

    1991-01-01

    An apparatus for the sequential fracturing and cutting of subsurface volume of hard rock (102) in the strata (101) of a mining environment (100) by subjecting the volume of rock to a beam (25) of microwave energy to fracture the subsurface volume of rock by differential expansion; and , then bringing the cutting edge (52) of a piece of conventional mining machinery (50) into contact with the fractured rock (102).

  15. Rad-Hard Silicon Detectors

    NASA Astrophysics Data System (ADS)

    Giorgi, Marco

    2005-06-01

    For the next generation of High Energy Physics (HEP) Experiments silicon microstrip detectors working in harsh radiation environments with excellent performances are necessary. The irradiation causes bulk and surface damages that modify the electrical properties of the detector. Solutions like AC coupled strips, overhanging metal contact, <100> crystal lattice orientation, low resistivity n-bulk and Oxygenated substrate are studied for rad-hard detectors. The paper presents an outlook of these technologies.

  16. Schwannoma of the hard palate

    PubMed Central

    Sahoo, Pradyumna Kumar; Mandal, Palash Kumar; Ghosh, Saradindu

    2014-01-01

    Schwannomas are benign encapsulated perineural tumors. The head and neck region is the most common site. Intraoral origin is seen in only 1% of cases, tongue being the most common site; its location in the palate is rare. We report a case of hard-palate schwannoma with bony erosion which was immunohistochemically confirmed. The tumor was excised completely intraorally. After two months of follow-up, the defect was found to be completely covered with palatal mucosa. PMID:25298716

  17. Hard-to-fill vacancies.

    PubMed

    Williams, Ruth

    2010-09-29

    Skills for Health has launched a set of resources to help healthcare employers tackle hard-to-fill entry-level vacancies and provide sustainable employment for local unemployed people. The Sector Employability Toolkit aims to reduce recruitment and retention costs for entry-level posts and repare people for employment through pre-job training programmes, and support employers to develop local partnerships to gain access to wider pools of candidates and funding streams.

  18. A radiation-hard, low-background multiplexer design for spacecraft imager applications

    NASA Technical Reports Server (NTRS)

    Staller, Craig; Ramirez, Luis; Niblack, Curtiss; Blessinger, Michael; Kleinhans, William

    1992-01-01

    A possible multiplexer design for the focal plane for the Cassini Visible and Infrared Mapping Spectrometer (VIMS) is reviewed. The instrument's requirements for the multiplexed array are summarized. The VIMS instrument has a modest radiation-hardness requirement due to the trajectory and planetary environments in which the instrument will be required to operate. The total ionizing dose hardness requirement is a few tens of kilorads. A thin-gate oxide of a few hundred angstroms thickness is to be used. Field hardness is to be achieved by guard bands or hardened dielectric isolation. The design is argued to meet the low-noise and radiation-hardness required for imaging at Saturn. The design is versatile enough to provide double-correlated and double-uncorrelated sampling, which is accomplished in the signal processing electronics outside the focal plane.

  19. Black Holes (With 16 figures)

    NASA Astrophysics Data System (ADS)

    Novikov, Igor

    Astrophysics of Black Holes Introduction The Origin of Stellar Black Holes A Nonrotating Black Hole Introduction Schwarzschild Gravitational Field Motion of Photons Along the Radial Direction Radial Motion of Nonrelativistic Particles The Puzzle of the Gravitational Radius R and T Regions Two Types of T-Regions Gravitational Collapse and White Holes Eternal Black Hole? Black Hole Celestial Mechanics Circular Motion Around a Black Hole Gravitational Capture of Particles by a Black Hole Corrections for Gravitational Radiation A Rotating Black Hole Introduction Gravitational Field of a Rotating Black Hole Specific Reference Frames General Properties of the Spacetime of a Rotating Black Hole; - Spacetime Inside the Horizon Celestial Mechanics of a Rotating Black Hole Motion of Particle in the Equatorial Plane Motion of Particles off the Equatorial Plane Peculiarities of the Gravitational Capture of Bodies by a Rotating - Black Hole Electromagnetic Fields Near a Black Hole Introduction Maxwell's Equations in the Neighborhood of a Rotating Black Hole Stationary Electrodynamics Boundary Conditions at the Event Horizon Electromagnetic Fields in Vacuum Magnetosphere of a Black Hole Some Aspects of Physics of Black Holes, Wormholes, and Time Machines Observational Appearence of the Black Holes in the Universe Black Holes in the Interstellar Medium Disk Accretion Black Holes in Stellar Binary Systems Black Holes in Galactic Centers Dynamical Evidence for Black Holes in Galaxy Nuclei Primordial Black Holes Acknowledgements References

  20. Why Are Drugs So Hard to Quit?

    MedlinePlus Videos and Cool Tools

    ... Quitting drugs is hard because addiction is a brain disease. Your brain is like a control tower that sends out ... and choices. Addiction changes the signals in your brain and makes it hard to feel OK without ...

  1. Fast multi-wavelength variability from a black hole

    NASA Astrophysics Data System (ADS)

    O'Brien, Kieran

    2011-10-01

    Correlated fast multi-wavelength variability is quickly becoming a key tool for studying the physics of accretion and ejection of relativistic jets. Using simultaneous X-ray and near-infrared data we have recently discovered vibrations from a relativistic jet down to 62.5 ms time scale, which allowed us to estimate the speed and the size of the jet. We have also shown that the properties of the jet depend on the spectral state of the black hole. We propose to monitor the outburst evolution of a black hole transient with XMM, simultaneously with ground-based optical and infrared facilities, in order to apply the same technique to different spectral states. We propose to perform 10 short XMM observations (7 ks each) of an active black hole, in order to cover the different stages of the outburst.

  2. Infrared: Beyond the Visible

    NASA Image and Video Library

    Infrared: Beyond the Visible, is a fast, fun look at why infrared light matters to astronomy, and what the Webb Space Telescope will search for once it's in orbit. Caption file available at: http:/...

  3. Jupiter Scar in Infrared

    NASA Image and Video Library

    2011-01-26

    These infrared images obtained from NASA Infrared Telescope Facility in Mauna Kea, Hawaii, show before and aftereffects from particle debris in Jupiter atmosphere after an object hurtled into the atmosphere on July 19, 2009.

  4. Infrared particle detection for battery electrode foils

    NASA Astrophysics Data System (ADS)

    Just, P.; Ebert, L.; Echelmeyer, T.; Roscher, M. A.

    2013-11-01

    Failures of electrochemical cells caused by internal shorts still are an important issue to be faced by the cell manufacturers and their customers. A major cause for internal shorts are contaminated electrode foils. These contaminations have to be detected securely via a non-destructive inspection technique integrated into the electrode manufacturing process. While optical detection already is state of the art, infrared detection of particles finds a new field of application in the battery electrode manufacturing process. This work presents two approaches focusing on electrode inspection by electromagnetic radiation (visible and infrared). Copper foils with a carbon based coating were intentionally contaminated by slivers of aluminum and copper as well as by abraded coating particles. Optical excitation by a flash and a luminescent lamp was applied at different angles in order to detect the reflected visible radiation. A laser impulse was used to heat up the specimen for infrared inspection. Both approaches resulted in setups providing a high contrast between contaminations and the coated electrode foil. It is shown that infrared detection offers a higher security thanks to its reliance on absorbance and emissivity instead of reflectivity as it is used for optical detection. Infrared Detection offers a potential since it is hardly influenced by the particle's shape and orientation and the electrode's waviness.

  5. Am I My Brother's Teacher? Black Undergraduates, Racial Socialization, and Peer Pedagogies in Predominantly White Postsecondary Contexts

    ERIC Educational Resources Information Center

    Harper, Shaun R.

    2013-01-01

    The aims of this article are twofold: (a) to review an extensive body of research that focuses almost exclusively on racial problems Black students face at predominantly White institutions (PWIs) and (b) to provide insights into how Black students manage to productively navigate racist college and university environments. Hardly anything has been…

  6. Am I My Brother's Teacher? Black Undergraduates, Racial Socialization, and Peer Pedagogies in Predominantly White Postsecondary Contexts

    ERIC Educational Resources Information Center

    Harper, Shaun R.

    2013-01-01

    The aims of this article are twofold: (a) to review an extensive body of research that focuses almost exclusively on racial problems Black students face at predominantly White institutions (PWIs) and (b) to provide insights into how Black students manage to productively navigate racist college and university environments. Hardly anything has been…

  7. Racial Battle Fatigue and the "Mis"Education of Black Men: Racial Microaggressions, Societal Problems, and Environmental Stress

    ERIC Educational Resources Information Center

    Smith, William A.; Hung, Man; Franklin, Jeremy D.

    2011-01-01

    Black men's lives are racialized contradictions, They are told that contemporary educational and professional institutions--particularly historically White institutions (HWls)--are places where, through hard work, they can achieve the so-called American dream. However, for far too many Black men, HWIs represent racial climates that are replete…

  8. An intermediate-mass black hole candidate in M51?

    NASA Astrophysics Data System (ADS)

    Earnshaw, H. M.

    2016-05-01

    We present the current results of an investigation into M51 ULX-7, using archival data from XMM-Newton, Chandra and NuSTAR, and optical and radio data from HST and VLA. The source has a consistently hard power-law X-ray spectrum and high short-term variability. This is unusual variability behaviour for a ULX, as we would expect highly variable ULXs to have soft energy spectra. The power spectrum features a break at ˜ 10-3 Hz, from low frequency spectral index α=0.1 to high frequency spectral index α=0.8, analogous to the low frequency break found in power spectra of black holes accreting in the low/hard state. We do not observe a corresponding high frequency break, however taking the white noise level as a frequency lower limit of the break, we can calculate a black hole mass upper limit of 9.12×104 M⊙, assuming that the ULX is in the low/hard state. While there is no radio detection, we find a flux density upper limit of 87 μJy/beam. Using the X-ray/radio fundamental plane, we calculate a black hole mass upper limit of 1.95×105 M⊙. Therefore, this ULX is consistent with being an IMBH accreting in the low/hard state.

  9. Black heel a minor hazard of sport.

    PubMed

    Wilkinson, D S

    1977-09-01

    "Black heel" (calcaneal petechiae) is a traumatic lesion affecting the back or posterolateral aspect of the heel. It is seen almost exclusively in adolescentes or young adults engaged in active sports, notably basketball, but also football, lacrosse, tennis, and so forth. The lesion is disposed horizontally at the upper dege of the calcaneal fat-pad and consists of grouped punctate hemorrhages, the nature of which is revealed by repeated paring of the lesion. The nature of the pigment is shown by specialized stains. "Black heel" is probably more common than is realized. It is likely to be cuased by a shearing or pinching stress from abrupt contact of th foot with a floor or hard ground. As it si usually symptomless, it may be disregarded or only observed by chance. However, it has been confused clinically with a melaonoa, and as it is such a trivial self-healing process, it is important that it be recognized for what it is.

  10. Are artificial neural networks black boxes?

    PubMed

    Benitez, J M; Castro, J L; Requena, I

    1997-01-01

    Artificial neural networks are efficient computing models which have shown their strengths in solving hard problems in artificial intelligence. They have also been shown to be universal approximators. Notwithstanding, one of the major criticisms is their being black boxes, since no satisfactory explanation of their behavior has been offered. In this paper, we provide such an interpretation of neural networks so that they will no longer be seen as black boxes. This is stated after establishing the equality between a certain class of neural nets and fuzzy rule-based systems. This interpretation is built with fuzzy rules using a new fuzzy logic operator which is defined after introducing the concept of f-duality. In addition, this interpretation offers an automated knowledge acquisition procedure.

  11. Ten shades of black

    NASA Astrophysics Data System (ADS)

    Hod, Shahar

    2015-09-01

    The holographic principle has taught us that, as far as their entropy content is concerned, black holes in (3 + 1)-dimensional curved spacetimes behave as ordinary thermodynamic systems in flat (2 + 1)-dimensional spacetimes. In this paper, we point out that the opposite behavior can also be observed in black-hole physics. To show this we study the quantum Hawking evaporation of near-extremal Reissner-Nordström (RN) black holes. We first point out that the black-hole radiation spectrum departs from the familiar radiation spectrum of genuine (3 + 1)-dimensional perfect black-body emitters. In particular, the would be black-body thermal spectrum is distorted by the curvature potential which surrounds the black-hole and effectively blocks the emission of low-energy quanta. Taking into account the energy-dependent gray-body factors which quantify the imprint of passage of the emitted radiation quanta through the black-hole curvature potential, we reveal that the (3 + 1)-dimensional black holes effectively behave as perfect black-body emitters in a flat (9 + 1)-dimensional spacetime.

  12. Warren G. Harding and the Press.

    ERIC Educational Resources Information Center

    Whitaker, W. Richard

    There are many parallels between the Richard M. Nixon administration and Warren G. Harding's term: both Republicans, both touched by scandal, and both having a unique relationship with the press. But in Harding's case the relationship was a positive one. One of Harding's first official acts as president was to restore the regular White House news…

  13. 30 CFR 56.15002 - Hard hats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hard hats. 56.15002 Section 56.15002 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Personal Protection § 56.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or plant where falling...

  14. 30 CFR 57.15002 - Hard hats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hard hats. 57.15002 Section 57.15002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Underground § 57.15002 Hard hats. All persons shall wear suitable hard hats when in or around a mine or...

  15. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  16. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  17. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  18. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  19. 7 CFR 201.57 - Hard seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at..., are to be counted as “hard seed.” If at the end of the germination period provided for legumes, okra... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at...

  20. Modeling and analyzing characteristics of self-infrared radiation on airplane-skin

    NASA Astrophysics Data System (ADS)

    Li, Zhaozhao; Wu, Wenyuan; Wu, Chengguo; Yang, Yuntao; Huang, Yanhua; Sunxiaobo, Zhuan

    2016-01-01

    The characteristic of the self-infrared radiation of airplane-skin is very important for the stealth performance of airplane. Based on the theory of the airplane-skin temperature field, the distribution of the atmospheric temperature field and the principle of the black-body radiation function the self-infrared radiation model was established. In specified flight conditions, the influence of the atmospheric temperature, the speed of flight, the emissivity and the sight angle detection on the self-infrared radiation of the airplane skin were analyzed. Through the simulation of infrared radiation, some results under different flight states are obtained. The simulation results show that skin infrared radiation energy mainly concentrate on the far infrared wavebands, and various factors have different effects on the infrared radiation of skin. This conclusion can help reduce the infrared radiation and improve the stealth performance of airplane in the engineering design and the selection of flight conditions.

  1. AN EVOLVING COMPACT JET IN THE BLACK HOLE X-RAY BINARY MAXI J1836-194

    SciTech Connect

    Russell, D. M.; Russell, T. D.; Miller-Jones, J. C. A.; Soria, R.; Slaven-Blair, T.; Curran, P. A.; O'Brien, K.; Sivakoff, G. R.; Lewis, F.; Markoff, S.; Altamirano, D.; Homan, J.; Rupen, M. P.; Dhawan, V.; Belloni, T. M.; Cadolle Bel, M.; Casella, P.; Corbel, S.; Gallo, E.; and others

    2013-05-10

    We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836-194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from {approx}10{sup 11} to {approx}4 Multiplication-Sign 10{sup 13} Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process.

  2. An Evolving Compact Jet in the Black Hole X-Ray Binary Maxi J1836-194

    NASA Technical Reports Server (NTRS)

    Russell, D. M.; Russell, T. D.; Miller-Jones, J. C. A.; O'Brien, K.; Soria, R.; Sivakoff, G. R.; Slaven-Blair, T.; Lewis, F.; Markoff, S.; Homan, J.; Altanirano, D.; Curran, P. A.; Rupen, M. P.; Belloni, T. M.; Cadolle Bel, M.; Casella, P.; Corbel, S.; Dhawan, V.; Fender, R. P.; Gallo, E.; Gandhi, P.; Heinz, S.; Koerding, E. G.; Krimm, H. A.; Maitra, D.

    2013-01-01

    We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836-194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from approx 10(exp 11) to approx 4 × 10(exp 13) Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process.

  3. An Evolving Compact Jet in the Black Hole X-Ray Binary MAXI J1836-194

    NASA Astrophysics Data System (ADS)

    Russell, D. M.; Russell, T. D.; Miller-Jones, J. C. A.; O'Brien, K.; Soria, R.; Sivakoff, G. R.; Slaven-Blair, T.; Lewis, F.; Markoff, S.; Homan, J.; Altamirano, D.; Curran, P. A.; Rupen, M. P.; Belloni, T. M.; Cadolle Bel, M.; Casella, P.; Corbel, S.; Dhawan, V.; Fender, R. P.; Gallo, E.; Gandhi, P.; Heinz, S.; Körding, E. G.; Krimm, H. A.; Maitra, D.; Migliari, S.; Remillard, R. A.; Sarazin, C. L.; Shahbaz, T.; Tudose, V.

    2013-05-01

    We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836-194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from ~1011 to ~4 × 1013 Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process. Based on observations collected at the European Southern Observatory, Chile, under ESO Program IDs 087.D-0914 and 089.D-0970.

  4. Observational signatures of binary supermassive black holes

    SciTech Connect

    Roedig, Constanze; Krolik, Julian H.; Miller, M. Coleman

    2014-04-20

    Observations indicate that most massive galaxies contain a supermassive black hole, and theoretical studies suggest that when such galaxies have a major merger, the central black holes will form a binary and eventually coalesce. Here we discuss two spectral signatures of such binaries that may help distinguish them from ordinary active galactic nuclei. These signatures are expected when the mass ratio between the holes is not extreme and the system is fed by a circumbinary disk. One such signature is a notch in the thermal continuum that has been predicted by other authors; we point out that it should be accompanied by a spectral revival at shorter wavelengths and also discuss its dependence on binary properties such as mass, mass ratio, and separation. In particular, we note that the wavelength λ {sub n} at which the notch occurs depends on these three parameters in such a way as to make the number of systems displaying these notches ∝λ{sub n}{sup 16/3}; longer wavelength searches are therefore strongly favored. A second signature, first discussed here, is hard X-ray emission with a Wien-like spectrum at a characteristic temperature ∼100 keV produced by Compton cooling of the shock generated when streams from the circumbinary disk hit the accretion disks around the individual black holes. We investigate the observability of both signatures. The hard X-ray signal may be particularly valuable as it can provide an indicator of black hole merger a few decades in advance of the event.

  5. The Relationship Between Grain Hardness, Dough Mixing Parameters and Bread-Making Quality in Winter Wheat

    PubMed Central

    Salmanowicz, Bolesław P.; Adamski, Tadeusz; Surma, Maria; Kaczmarek, Zygmunt; Karolina, Krystkowiak; Kuczyńska, Anetta; Banaszak, Zofia; Ługowska, Bogusława; Majcher, Małgorzata; Obuchowski, Wiktor

    2012-01-01

    The influence of grain hardness, determined by using molecular markers and physical methods (near-infrared (NIR) technique and particle size index—PSI) on dough characteristics, which in turn were determined with the use of a farinograph and reomixer, as well as bread-making properties were studied. The material covered 24 winter wheat genotypes differing in grain hardness. The field experiment was conducted at standard and increased levels of nitrogen fertilization. Results of molecular analyses were in agreement with those obtained by the use of physical methods for soft-grained lines. Some lines classified as hard (by physical methods) appeared to have the wild-type Pina and Pinb alleles, similar to soft lines. Differences in dough and bread-making properties between lines classified as hard and soft on the basis of molecular data appeared to be of less significance than the differences between lines classified as hard and soft on the basis of physical analyses of grain texture. Values of relative grain hardness at the increased nitrogen fertilization level were significantly higher. At both fertilization levels the NIR parameter determining grain hardness was significantly positively correlated with the wet gluten and sedimentation values, with most of the rheological parameters and bread yield. Values of this parameter correlated with quality characteristics in a higher degree than values of particle size index. PMID:22605973

  6. The relationship between grain hardness, dough mixing parameters and bread-making quality in winter wheat.

    PubMed

    Salmanowicz, Bolesław P; Adamski, Tadeusz; Surma, Maria; Kaczmarek, Zygmunt; Karolina, Krystkowiak; Kuczyńska, Anetta; Banaszak, Zofia; Lugowska, Bogusława; Majcher, Małgorzata; Obuchowski, Wiktor

    2012-01-01

    The influence of grain hardness, determined by using molecular markers and physical methods (near-infrared (NIR) technique and particle size index-PSI) on dough characteristics, which in turn were determined with the use of a farinograph and reomixer, as well as bread-making properties were studied. The material covered 24 winter wheat genotypes differing in grain hardness. The field experiment was conducted at standard and increased levels of nitrogen fertilization. Results of molecular analyses were in agreement with those obtained by the use of physical methods for soft-grained lines. Some lines classified as hard (by physical methods) appeared to have the wild-type Pina and Pinb alleles, similar to soft lines. Differences in dough and bread-making properties between lines classified as hard and soft on the basis of molecular data appeared to be of less significance than the differences between lines classified as hard and soft on the basis of physical analyses of grain texture. Values of relative grain hardness at the increased nitrogen fertilization level were significantly higher. At both fertilization levels the NIR parameter determining grain hardness was significantly positively correlated with the wet gluten and sedimentation values, with most of the rheological parameters and bread yield. Values of this parameter correlated with quality characteristics in a higher degree than values of particle size index.

  7. Infrared detectors for Earth observation

    NASA Astrophysics Data System (ADS)

    Barnes, K.; Davis, R. P.; Knowles, P.; Shorrocks, N.

    2016-05-01

    IASI (Infrared Atmospheric Sounding Interferometer), developed by CNES and launched since 2006 on the Metop satellites, is established as a major source of data for atmospheric science and weather prediction. The next generation - IASI NG - is a French national contribution to the Eumetsat Polar System Second Generation on board of the Metop second generation satellites and is under development by Airbus Defence and Space for CNES. The mission aim is to achieve twice the performance of the original IASI instrument in terms of sensitivity and spectral resolution. In turn, this places very demanding requirements on the infrared detectors for the new instrument. Selex ES in Southampton has been selected for the development of the infrared detector set for the IASI-NG instruments. The wide spectral range, 3.6 to 15.5 microns, is covered in four bands, each served by a dedicated detector design, with a common 4 x 4 array format of 1.3 mm square macropixels. Three of the bands up to 8.7 microns employ photovoltaic MCT (mercury cadmium telluride) technology and the very long wave band employs photoconductive MCT, in common with the approach taken between Airbus and Selex ES for the SEVIRI instrument on Second Generation Meteosat. For the photovoltaic detectors, the MCT crystal growth of heterojunction photodiodes is by the MOVPE technique (metal organic vapour phase epitaxy). Novel approaches have been taken to hardening the photovoltaic macropixels against localised crystal defects, and integrating transimpedance amplifiers for each macropixel into a full-custom silicon read out chip, which incorporates radiation hard design.

  8. Uniformly accelerated black holes

    NASA Astrophysics Data System (ADS)

    Letelier, Patricio S.; Oliveira, Samuel R.

    2001-09-01

    The static and stationary C metric are examined in a generic framework and their interpretations studied in some detail, especially those with two event horizons, one for the black hole and another for the acceleration. We find that (i) the spacetime of an accelerated static black hole is plagued by either conical singularities or a lack of smoothness and compactness of the black hole horizon, (ii) by using standard black hole thermodynamics we show that accelerated black holes have a higher Hawking temperature than Unruh temperature of the accelerated frame, and (iii) the usual upper bound on the product of the mass and acceleration parameters (<1/27) is just a coordinate artifact. The main results are extended to accelerated rotating black holes with no significant changes.

  9. Exploring Black Hole Dynamics

    NASA Astrophysics Data System (ADS)

    Chung, Hyeyoun

    2015-10-01

    This thesis explores the evolution of different types of black holes, and the ways in which black hole dynamics can be used to answer questions about other physical systems. We first investigate the differences in observable gravitational effects between a four-dimensional Randall-Sundrum (RS) braneworld universe compared to a universe without the extra dimension, by considering a black hole solution to the braneworld model that is localized on the brane. When the brane has a negative cosmological constant, then for a certain range of parameters for the black hole, the intersection of the black hole with the brane approximates a Banados-Teitelboim-Zanelli (BTZ) black hole on the brane with corrections that fall off exponentially outside the horizon. We compute the quasinormal modes of the braneworld black hole, and compare them to the known quasinormal modes of the three-dimensional BTZ black hole. We find that there are two distinct regions for the braneworld black hole solutions that are reflected in the dependence of the quasinormal modes on the black hole mass. The imaginary parts of the quasinormal modes display phenomenological similarities to the quasinormal modes of the three-dimensional BTZ black hole, indicating that nonlinear gravitational effects may not be enough to distinguish between a lower-dimensional theory and a theory derived from a higher-dimensional braneworld. Secondly, we consider the evolution of non-extremal black holes in N=4, d=2 supergravity, and investigate how such black holes might evolve over time if perturbed away from extremality. We study this problem in the probe limit by finding tunneling amplitudes for a Dirac field in a single-centered background, which gives the decay rates for the emission of charged probe black holes from the central black hole. We find that there is no minimum to the potential for the probe particles at a finite distance from the central black hole, so any probes that are emitted escape to infinity. If

  10. Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Loeb, Abraham

    2007-04-01

    Recent data indicates that almost all galaxies possess a supermassive black hole at their center. When gas accretes onto the black hole it heats-up and shines, resulting in the appearance of a bright quasar. The earliest quasars are found to exist only a billion years after the big-bang. I will describe recent observations of both the nearest and the most distant supermassive black holes in the universe. The formation and evolution of the black hole population can be described in the context of popular models for galaxy formation. I will describe the key questions that drive current research on supermassive black holes and present theoretical work on the radiative and hydrodynamic effects that quasars have on their cosmic habitat. Within the coming decade it would be possible to test general relativity by monitoring over time, and possibly even imaging, the polarized emission from hot spots around the black hole in the center of our Galaxy (SgrA*).

  11. The hard problem of cooperation.

    PubMed

    Eriksson, Kimmo; Strimling, Pontus

    2012-01-01

    Based on individual variation in cooperative inclinations, we define the "hard problem of cooperation" as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition) change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior.

  12. The Hard Problem of Cooperation

    PubMed Central

    Eriksson, Kimmo; Strimling, Pontus

    2012-01-01

    Based on individual variation in cooperative inclinations, we define the “hard problem of cooperation” as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition) change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior. PMID:22792282

  13. Radiation hard electronics for LHC

    NASA Astrophysics Data System (ADS)

    Raymond, M.; Millmore, M.; Hall, G.; Sachdeva, R.; French, M.; Nygård, E.; Yoshioka, K.

    1995-02-01

    A CMOS front end electronics chain is being developed by the RD20 collaboration for microstrip detector readout at LHC. It is based on a preamplifier and CR-RC filter, analogue pipeline and an analogue signal processor. Amplifiers and transistor test structures have been constructed and evaluated in detail using a Harris 1.2 μm radiation hardened CMOS process. Progress with larger scale elements, including 32 channel front end chips, is described. A radiation hard 128 channel chip, with a 40 MHz analogue multiplexer, is to be submitted for fabrication in July 1994 which will form the basis of the readout of the tracking system of the CMS experiment.

  14. Micromagnetic Modeling of Hard Magnets

    NASA Astrophysics Data System (ADS)

    Fidler, J.

    1997-03-01

    The increasing impact of magnetic materials on many modern industries will continue well into the next century. Besides recording materials and soft magnetic devices , also hard magnetic materials are key components in transportation and information technologies, machines and many other systems. For the better understanding and the development of high performance permanent magnets a detailed understanding of the magnetization mechanisms leading to an improvement of the coercive field is necessary. Various approaches have been proposed to describe the coercivity of permanent magnets. Besides the micromagnetic approach of the nucleation of reversed domains, the expansion mechanism or the domain wall propagation, also other phenomenological approaches taking into account the magnetocrystalline anisotropy energy and the magnetic viscosity have been used. The hysteresis properties are governed by a combination of the intrinsic properties of the material, such as saturation polarization, magnetic exchange and magnetocrystalline anisotropy. The other important factors are the microstructural parameters, such as grain size, the orientation of the easy axes of the grains and the distribution of phases. The role of intergranular structure between the grains plays a significant role determining the magnetic properties, if the grain diameter is in the nanometer scale. It is intended to show the relationship between the magnetization reversal behavior and the real microstructure of various types of hard magnets, especially of rare earth permanent magnets. The theoretical treatment of the magnetization reversal processes is performed in the framework of the continuum theory of micromagnetism. Starting from a real microstructure, characterized by optical and electron microscopic techniques, the influence of the dipolar and the exchange interaction between hard magnetic grains has been demonstrated mainly on Nd-Fe-B magnets. We developed a numerical algorithm on the basis of

  15. Radiation Hardness Assurance (RHA) Guideline

    NASA Technical Reports Server (NTRS)

    Campola, Michael J.

    2016-01-01

    Radiation Hardness Assurance (RHA) consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the mission space environment. The subset of interests for NEPP and the REAG, are EEE parts. It is important to register that all of these undertakings are in a feedback loop and require constant iteration and updating throughout the mission life. More detail can be found in the reference materials on applicable test data for usage on parts.

  16. Hard Scattering Studies at Jlab

    SciTech Connect

    Harutyun Avagyan; Peter Bosted; Volker Burkert; Latifa Elouadrhiri

    2005-09-01

    We present current activities and future prospects for studies of hard scattering processes using the CLAS detector and the CEBAF polarized electron beam. Kinematic dependences of single and double spin asymmetries have been measured in a wide kinematic range at CLAS with a polarized NH{sub 3} and unpolarized liquid hydrogen targets. It has been shown that the data are consistent with factorization and observed target and beam asymmetries are in good agreement with measurements performed at higher energies, suggesting that the high energy-description of the semi-inclusive DIS process can be extended to the moderate energies of JLab measurements.

  17. 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.

  18. The Nearest Black Holes

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); Garcia, M.

    2003-01-01

    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. This program facilitates this study by funding related travel, computer equipment, and partial salary for a post-doc.

  19. The Nearest Black Holes

    NASA Technical Reports Server (NTRS)

    Garcia, M.; Oliversen, Ronald J. (Technical Monitor)

    2004-01-01

    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. This program facilitate this study by funding related travel, computer equipment, and partial salary for a post-doc.

  20. 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…

  1. 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…

  2. Hardness correlation for uranium and its alloys

    SciTech Connect

    Humphreys, D L; Romig, Jr, A D

    1983-03-01

    The hardness of 16 different uranium-titanium (U-Ti) alloys was measured on six (6) different hardness scales (R/sub A/, R/sub B/, R/sub C/, R/sub D/, Knoop, and Vickers). The alloys contained between 0.75 and 2.0 wt % Ti. All of the alloys were solutionized (850/sup 0/C, 1 h) and ice-water quenched to produce a supersaturated martensitic phase. A range of hardnesses was obtained by aging the samples for various times and temperatures. The correlation of various hardness scales was shown to be virtually identical to the hardness-scale correlation for steels. For more-accurate conversion from one hardness scale to another, least-squares-curve fits were determined for the various hardness-scale correlations. 34 figures, 5 tables.

  3. Asymptotic black holes

    NASA Astrophysics Data System (ADS)

    Ho, Pei-Ming

    2017-04-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  4. Evidence for black holes.

    PubMed

    Begelman, Mitchell C

    2003-06-20

    Black holes are common objects in the universe. Each galaxy contains large numbers-perhaps millions-of stellar-mass black holes, each the remnant of a massive star. In addition, nearly every galaxy contains a supermassive black hole at its center, with a mass ranging from millions to billions of solar masses. This review discusses the demographics of black holes, the ways in which they interact with their environment, factors that may regulate their formation and growth, and progress toward determining whether these objects really warp spacetime as predicted by the general theory of relativity.

  5. Quasar Outflows and Black Hole Masses

    NASA Astrophysics Data System (ADS)

    Coatman, Liam; Hewett, Paul; Banerji, Manda; Richards, Gordon; Hennawi, Joseph; Prochaska, Jason X.

    2016-08-01

    Black-hole masses are crucial to understanding the physics of the connection between quasars and their host galaxies and measuring cosmic black hole-growth. At high redshift, z > 2, black hole masses are normally derived using the velocity-width of the CIV broad emission line, based on the assumption that the observed velocity-widths arise from virial-induced motions. In many quasars, the CIV-emission line exhibits significant blue asymmetries ('blueshifts') with the line centroid displaced by up to thousands of km/s to the blue. These blueshifts almost certainly signal the presence of strong outflows, most likely originating in a disc wind. Using both archival data and new observations, we have obtained near-infrared spectra, including the Ha and/or Hb emission lines, for ~400 luminous (L_Bol = 45.5-48.5 erg/s) SDSS quasars, at redshifts 1.5 < z < 4, with CIV emission lines spanning the full-range of blueshifts present in the population. A strong correlation between CIV-velocity width and blueshift is found and, at large blueshifts, >2000 km/s, the velocity-widths appear to be dominated by non-virial motions. Using the Ha/Hb emission to provide black hole masses free from non-virial contributions, we are able to derive a quantitative correction to the CIV-based black-hole masses as a function of blueshift. This correction reduces the scatter between Ha/Hb and CIV velocity widths to just ~0.1 dex. Without the correction, black hole masses would be overestimated by a factor of nine at the largest blueshifts. With a suitable systemic redshift-estimation algorithm, this correction can be straightforwardly applied based only on information contained in the rest-frame UV spectra.

  6. Removal of brownish-black tarnish on silver-copper alloy objects with sodium glycinate

    NASA Astrophysics Data System (ADS)

    de Figueiredo, João Cura D.'Ars; Asevedo, Samara Santos; Barbosa, João Henrique Ribeiro

    2014-10-01

    This article has the principal aim of presenting a new method of chemical cleaning of tarnished silver-copper alloy objects. The chemical cleaning must be harmless to the health, selective to tarnish removal, and easy to use. Sodium glycinate was selected for the study. The reactions of sodium glycinate with tarnish and the silver-copper alloy were evaluated. Products of the reaction, the lixiviated material, and the esthetics of silver-copper alloy coins (used as prototypes) were studied to evaluate if the proposed method can be applied to the cleaning of silver objects. Silver-copper alloys can be deteriorated through a uniform and superficial corrosion process that produces brownish-black tarnish. This tarnish alters the esthetic of the object. The cleaning of artistic and archeological objects requires more caution than regular cleaning, and it must take into account the procedures for the conservation and restoration of cultural heritage. There are different methods for cleaning silver-copper alloy objects, chemical cleaning is one of them. We studied two chemical cleaning methods that use sodium glycinate and sodium acetylglycinate solutions. Silver-copper alloy coins were artificially corroded in a basic thiourea solution and immersed in solutions of sodium glycinate and sodium acetylglycinate. After immersion, optical microscopy and scanning electron microscopy of the surfaces were studied. The sodium glycinate solution was shown to be very efficient in removing the brownish-black tarnish. Absorption spectroscopy measured the percentage of silver and copper lixiviated in immersion baths, and very small quantities of these metals were detected. Infrared absorption spectroscopy and X-ray fluorescence characterized the obtained products. The greater efficiency of the sodium glycinate solution compared to the sodium acetylglycinate solution was explained by chelation and Hard-Soft Acid-Base Theory with the aid of quantum chemical calculations.

  7. Effects of Water Hardness on Textile Detergency Performance in Aqueous Cleaning Systems.

    PubMed

    Gotoh, Keiko; Horibe, Kaori; Mei, Yang; Tsujisaka, Toshiyuki

    2016-01-01

    The effects of water hardness on textile detergency in aqueous solutions were systematically investigated using four surfactants: sodium oleate (OLNa), linear dodecylbenzene sulfonate (LAS), sodium dodecyl sulfate (AS), and polyoxyethylene (10) dodecyl ether (AE). Water hardness was adjusted according to the standard procedure described in IEC 60734:2012. As expected, by adding hardness salts the surface tension of the OLNa solution increased. Surprisingly, the addition of hardness salts lowers the surface tension for the LAS and AS solutions. In the case of the AE solution, hardness salt did not affect the surface tension. A decrease in transmittance and foamability after adding hardness salts was observed for every anionic surfactant solution, indicating that anionic surfactants can combine with divalent ions to form insoluble precipitates. Detergency experiments were performed using cotton plain-woven and towel fabrics soiled with a carbon black and oleic acid mixture. One piece each of untreated and soiled fabric were stacked and placed horizontally in detergent solution with or without hardness salts. As a mechanical action of soil removal, the shaking of 190 spm was applied. Soil removal and redeposition due to washing were evaluated from changes in values of the Kubelka-Munk function for both fabrics. With increasing water hardness, soil removal decreased and redeposition increased. In order of decreasing detergency, the surfactants were as follows: LAS > OLNa ≈ AS > AE. The results indicate that precipitates, formed by reaction of LAS or AS with hardness salts, are strongly adsorbed on the water surface because of their hydrophobicity, but they have no detergency power. The field emission scanning electron microscopic observation and X-ray photoelectron spectroscopic analysis showed that Ca(LAS)2 precipitation clung to fiber surfaces, and remained on the surfaces after washing. Significant changes in the cotton fabric due to washing were observed in

  8. The physics of black hole x ray novae

    NASA Technical Reports Server (NTRS)

    Wheeler, J. C.; Kim, S.-W.; Moscoso, M. D.; Mineshige, S.

    1994-01-01

    X-ray transients that are established or plausible black hole candidates have been discovered at a rate of about one per year in the galaxy for the last five years. There are now well over a dozen black hole candidates, most being in the category of X-ray novae with low-mass companions. There may be hundreds of such transient systems in the galaxy yet to be discovered. Classic black hole candidates like Cygnus X-1 with massive companions are in the minority, and their census in the galaxy and magellanic clouds is likely to be complete. The black hole X-ray novae (BHXN) do not represent only the most common environment in which to discover black holes. Their time dependence gives a major new probe with which to study the physics of accretion into black holes. The BHXN show both a soft X-ray flux from an optically thick disk and a hard power law tail that is reminiscent of AGN spectra. The result may be new insight into the classical systems like Cyg X-1 and LMC X-1 that show similar power law tails, but also to accretion into supermassive black holes and AGN.

  9. Towards infrared image understanding

    NASA Astrophysics Data System (ADS)

    Foulkes, Peter

    An extensive literature survey has revealed that the majority of previous work in infrared image processing ha ignored the processes leading to the formation of infrared images. Processing has normally either been restricted to simple low-level image enhancement convolutions or has consisted of algorithms copied from computer vision without regard for the inherent differences between infrared and visible images. In this thesis, we address the problem of infrared image formation and derive an irradiance equation for simple infrared scenes. We consider the complications caused by mutual illumination of one or more bodies and indicate how the infrared irradiance equation can also be specified for more complex scenes. The infrared irradiance equation we derive is solved in closed form for some simple geometries for both Lambertian and non-Lambertian surfaces. An infrared imager has been built and is described. Images taken with the imager of a variety of scene geometries show that the experimental results compare favorably with the theoretically derived equations, indicating the validity of the theoretical analysis. We describe how a knowledge of the formation of infrared images can be used to predict the image irradiance pattern of a particular object. We also show how, with a knowledge of the radiance properties and surface geometry of the object, it is possible to detect instances of that object in a scene. Examples are given of successful object detection based on an understanding of the image irradiance. We present a brief history of infrared imagers and a description of the principles on which modern infrared imagers are based. In addition to the survey of the literature published on infrared image processing, a brief summary of some techniques from the computer vision literature and their suitability to infrared image processing is given. A selection of vision techniques are applied to both infrared and visible images to verify conclusions reached in the thesis.

  10. Towards Infrared Image Understanding

    NASA Astrophysics Data System (ADS)

    Foulkes, Peter

    Available from UMI in association with The British Library. Requires signed TDF. An extensive literature survey has revealed that the majority of previous work in infrared image processing has ignored the processes leading to the formation of infrared images. Processing has normally either been restricted to simple low-level image enhancement convolutions or has consisted of algorithms copied from computer vision without regard for the inherent differences between infrared and visible images. In this thesis, we address the problem of infrared image formation and derive an irradiance equation for simple infrared scenes. We consider the complications caused by mutual illumination of one or more bodies and indicate how the infrared irradiance equation can also be specified for more complex scenes. The infrared irradiance equation we derive is solved in closed form for some simple geometries for both Lambertian and non-Lambertian surfaces. An infrared imager has been built and is described. Images taken with the imager of a variety of scene geometries show that the experimental results compare favourably with the theoretically derived equations, indicating the validity of the theoretical analysis. We describe how a knowledge of the formation of infrared images can be used to predict the image irradiance pattern of a particular object. We also show how, with a knowledge of the radiance properties and surface geometry of the object, it is possible to detect instances of that object in a scene. Examples are given of successful object detection based on an understanding of the image irradiance. We present a brief history of infrared imagers and a description of the principles on which modern infrared imagers are based. In addition to the survey of the literature published on infrared image processing, a brief summary of some techniques from the computer vision literature and their suitability to infrared image processing is given. A selection of vision techniques are

  11. Hard and Soft Safety Verifications

    NASA Technical Reports Server (NTRS)

    Wetherholt, Jon; Anderson, Brenda

    2012-01-01

    The purpose of this paper is to examine the differences between and the effects of hard and soft safety verifications. Initially, the terminology should be defined and clarified. A hard safety verification is datum which demonstrates how a safety control is enacted. An example of this is relief valve testing. A soft safety verification is something which is usually described as nice to have but it is not necessary to prove safe operation. An example of a soft verification is the loss of the Solid Rocket Booster (SRB) casings from Shuttle flight, STS-4. When the main parachutes failed, the casings impacted the water and sank. In the nose cap of the SRBs, video cameras recorded the release of the parachutes to determine safe operation and to provide information for potential anomaly resolution. Generally, examination of the casings and nozzles contributed to understanding of the newly developed boosters and their operation. Safety verification of SRB operation was demonstrated by examination for erosion or wear of the casings and nozzle. Loss of the SRBs and associated data did not delay the launch of the next Shuttle flight.

  12. AGN in the Swift/BAT and INTEGRAL Hard X-ray Surveys

    NASA Technical Reports Server (NTRS)

    Beckmann, Volker; Tueller, Jack; Baumgartner, Wayne; Markwardt, Craig; Mushotzky, Richard; Skinner, Gerry

    2008-01-01

    Two hard X-ray surveys are in progress at this time. They provide a unique new window on compact objects and black holes. I will discuss how these two surveys complement each other and the potential for improved coordination that could yield significant near term results in both sensitivity and time coverage. I will pay particular attention to the discovery of faint sources including new results from the 36 month survey from Swift/Burst Alert Telescope (BAT).

  13. AGN in the Swift/BAT and INTEGRAL Hard X-ray Surveys

    NASA Technical Reports Server (NTRS)

    Beckmann, Volker; Tueller, Jack; Baumgartner, Wayne; Markwardt, Craig; Mushotzky, Richard; Skinner, Gerry

    2008-01-01

    Two hard X-ray surveys are in progress at this time. They provide a unique new window on compact objects and black holes. I will discuss how these two surveys complement each other and the potential for improved coordination that could yield significant near term results in both sensitivity and time coverage. I will pay particular attention to the discovery of faint sources including new results from the 36 month survey from Swift/Burst Alert Telescope (BAT).

  14. Black phosphorus photodetector for multispectral, high-resolution imaging.

    PubMed

    Engel, Michael; Steiner, Mathias; Avouris, Phaedon

    2014-11-12

    Black phosphorus is a layered semiconductor that is intensely researched in view of applications in optoelectronics. In this letter, we investigate a multilayer black phosphorus photodetector that is capable of acquiring high-contrast (V > 0.9) images both in the visible (λVIS = 532 nm) as well as in the infrared (λIR = 1550 nm) spectral regime. In a first step, by using photocurrent microscopy, we map the active area of the device and we characterize responsivity and gain. In a second step, by deploying the black phosphorus device as a point-like detector in a confocal microsope setup, we acquire diffraction-limited optical images with submicron resolution. The results demonstrate the usefulness of black phosphorus as an optoelectronic material for hyperspectral imaging applications.

  15. One high performance technology of infrared scene projection

    NASA Astrophysics Data System (ADS)

    Wang, Hong-jie; Qian, Li-xun; Cao, Chun; Li, Zhuo

    2014-11-01

    Infrared scenes generation technologies are used to simulate the infrared radiation characteristics of target and background in the laboratory. They provide synthetic infrared imagery for thermal imager test and evaluation application in the infrared imaging systems. At present, many Infrared scenes generation technologies have been widely used, and they make a lot of achievements. In this paper, we design and manufacture one high performance IR scene generation technology, and the whole thin film type transducer is the key, which is fabricated based on micro electro mechanical systems (MEMS). The specific MEMS technological process parameters are obtained from a large number of experiments. The properties of infrared scene generation chip are investigated experimentally. It achieves high resolution, high frame, and reliable performance, which can meet the requirements of most simulation system. The radiation coefficient of the thin film transducer is measured to be 0.86. The frame rate is 160 Hz. The emission spectrum is from 2μm to 12μm in infrared band. Illuminated by the visible light with different intensities the equivalent black body temperature of transducer could be varied in the range of 290K to 440K. The spatial resolution is more than 256×256.The geometric distortion and the uniformity of the generated infrared scene is 5 percent. The infrared scene generator based on the infrared scene generation chip include three parts, which are visual image projector, visual to thermal transducer and the infrared scene projector. The experimental results show that this thin film type infrared scene generation chip meets the requirements of most of hardware-in-the-loop scene simulation systems for IR sensors testing.

  16. Infrared Sapce Astrometry missions: JASMINE

    NASA Astrophysics Data System (ADS)

    Gouda, Naoteru

    2015-08-01

    JASMINE is an abbreviation for Japan Astrometry Satellite Mission for INfrared Exploration. We are now focusing on the development of two projects, those are Nano-JASMINE and Small-JASMINE. The Nano-JASMINE micro-satellite project, with a primary mirror aperture of 5-cm class, is currently underway to test part of the technologies used for Small-JASMINE and to produce scientific results based on the astrometric information of bright objects in the neighboring space. Despite its small aperture, the satellite is capable of a level of observational precision comparable to the Hipparcos satellite, and the combination of the observational data from Nano-JASMINE and the Hipparcos Catalogue is expected to produce more precise data on proper motions and annual parallaxes. The satellite is scheduled for launch in the near future. An additional plan is underway to launch a small-scale JASMINE satellite (Small-JASMINE), with a primary mirror aperture of 30-cm class, in around FY 2021. This satellite will engage in observations of only a limited area around the bulge and certain specific astronomical objects.. The main scientific objective of Small-JASMINE is to clarify the dynamical structure of the Galactic nuclear bulge and search for observational relics of a sequential merger of multiple black holes to form the supermassive black hole at the Galactic center. In particular, our main goal is that Small-JASMINE will provide an understanding of the past evolution processes of the supermassive black hole and a prediction of the future activities of our Galactic center through knowledge of the gravitational potential in the Galactic nuclear bulge, and that this understanding can contribute to a better understanding of the co-evolution of the supermassive black holes and bulges in external galaxies. Next to this primary goal, Small-JASMINE will have many other scientific targets. Small-JASMINE can measure the same target every 100 minutes, so it is useful to resolve phenomena

  17. Black Silicon for Next-Generation Infrared Sensors

    DTIC Science & Technology

    2012-08-01

    3 0 0 n m Ion-implant chalcogen (S, Se, Te) into p-Si (1) Pulsed-laser melting ( PLM ) “heals” implant damage Crystalline Si, supersaturated...34@ N 0.50 ro E ~ 0 0.25 c A = (1 - R - T) I (1 - R) fs-laser doping , , lon implant+ PLM doping ,..,1020 em""’ chalcogens silicon w fer S.Si

  18. Hard Gamma Ray Emission from the Starburst Galaxy NGC 253

    NASA Technical Reports Server (NTRS)

    Jackson, James M.; Marscher, Alan M.

    1996-01-01

    We have completed the study to search for hard gamma ray emission from the starburst galaxy NGC 253. Since supernovae are thought to provide the hard gamma ray emission from the Milky Way, starburst galaxies, with their extraordinarily high supernova rates, are prime targets to search for hard gamma ray emission. We conducted a careful search for hard gamma ray emission from NGC 253 using the archival data from the EGRET experiment aboard the CGRO. Because this starburst galaxy happens to lie near the South Galactic Pole, the Galactic gamma ray background is minimal. We found no significant hard gamma ray signal toward NGC 253, although a marginal signal of about 1.5 sigma was found. Because of the low Galactic background, we obtained a very sensitive upper limit to the emission of greater than 100 MeV gamma-rays of 8 x 10(exp -8) photons/sq cm s. Since we expected to detect hard gamma ray emission, we investigated the theory of gamma ray production in a dense molecular medium. We used a leaky-box model to simulate diffusive transport in a starburst region. Since starburst galaxies have high infrared radiation fields, we included the effects of self-Compton scattering, which are usually ignored. By modelling the expected gamma-ray and synchrotron spectra from NGC 253, we find that roughly 5 - 15% of the energy from supernovae is transferred to cosmic rays in the starburst. This result is consistent with supernova acceleration models, and is somewhat larger than the value derived for the Galaxy (3 - 10%). Our calculations match the EGRET and radio data very well with a supernova rate of 0.08/ yr, a magnetic field B approx. greater than 5 x 10(exp -5) G, a density n approx. less than 100/sq cm, a photon density U(sub ph) approx. 200 eV/sq cm, and an escape time scale tau(sub 0) approx. less than 10 Myr. The models also suggest that NGC 253 should be detectable with only a factor of 2 - 3 improvement in sensitivity. Our results are consistent with the standard picture

  19. Plasmonic black metals in resonant nanocavities

    NASA Astrophysics Data System (ADS)

    Bora, Mihail; Behymer, Elaine M.; Dehlinger, Dietrich A.; Britten, Jerald A.; Larson, Cindy C.; Chang, Allan S. P.; Munechika, Keiko; Nguyen, Hoang T.; Bond, Tiziana C.

    2013-06-01

    We investigate a plasmonic resonant structure tunable from ultra-violet to near infrared wavelengths with maximum absorbance strength over 95% due to a highly efficient coupling with incident light. Additional harmonics are excited at higher frequencies extending the absorbance range to multiple wavelengths. We propose the concept of a plasmonic black metal nanoresonator that exhibits broadband absorbance characteristics by spacing the modes closer through increasing the resonator length and by employing adiabatic plasmonic nano-focusing on the tapered end of the cavity.

  20. Universal diffusion in incoherent black holes

    NASA Astrophysics Data System (ADS)

    Blake, Mike

    2016-10-01

    We study charge and energy diffusion in simple holographic theories with broken translational symmetry. We find that when the effects of momentum relaxation are very strong the diffusion constants take universal values Dc˜De˜ℏvB2/(kBT ) . Here vB is the velocity of the butterfly effect and the coefficients of proportionality depend only on the scaling exponents of the infra-red fixed point. Our results suggest that diffusion in these incoherent black holes is controlled by τ ˜ℏ/(kBT ) independently of the mechanism of momentum relaxation.