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Sample records for absorbs infrared radiation

  1. Mushroom plasmonic metamaterial infrared absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-01

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF2 etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  2. Mushroom plasmonic metamaterial infrared absorbers

    SciTech Connect

    Ogawa, Shinpei Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-26

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF{sub 2} etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  3. Optimum combinations of visible and near-infrared reflectances for estimating the fraction of photosynthetically available radiation absorbed by plants

    NASA Technical Reports Server (NTRS)

    Podaire, Alain; Deschamps, Pierre-Yves; Frouin, R.; Asrar, Ghassem

    1991-01-01

    A useful parameter to estimate terrestrial primary productivity, that can be sensed from space, is the daily averaged fraction of Photosynthetically Available Radiation (PAR) absorbed by plants. To evaluate this parameter, investigators have relied on the fact that the relative amount of radiation reflected by a vegetated surface in the visible and near infrared depends on the fraction of the surface covered by the vegetation and therefore, correlates with absorbed PAR. They have used vegetation indices, namely normalized difference and simple ratio, to derive absorbed PAR. The problem with normalized difference and simple ratio is first, they are non linear functions of radiance or reflectance and therefore, cannot be readily applied to heterogeneous targets, second, they are used in generally nonlinear relationships, which make time integrals of the indices not proportional to primary productivity, and third, the relationships depend strongly on the type of canopy and background. To remove these limitations, linear combinations of visible and near infrared reflectances at optimum (one or two) viewing zenith angles are proposed.

  4. Infrared bolometers with silicon nitride micromesh absorbers

    NASA Technical Reports Server (NTRS)

    Bock, J. J.; Turner, A. D.; DelCastillo, H. M.; Beeman, J. W.; Lange, A. E.; Mauskopf, P. D.

    1996-01-01

    Sensitive far infrared and millimeter wave bolometers fabricated from a freestanding membrane of low stress silicon nitride are reported. The absorber, consisting of a metallized silicon nitride micromesh thermally isolated by radial legs of silicon nitride, is placed in an integrating cavity to efficiently couple to single mode or multiple mode infrared radiation. This structure provides low heat capacity, low thermal conduction and minimal cross section to energetic particles. A neutron transmutation doped Ge thermister is bump bonded to the center of the device and read out with evaporated Cr-Au leads. The limiting performance of the micromesh absorber is discussed and the recent results obtained from a 300 mK cold stage are summarized.

  5. Absorber for terahertz radiation management

    DOEpatents

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  6. Solar radiation absorbing material

    DOEpatents

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  7. Ultra-broadband infrared metasurface absorber.

    PubMed

    Guo, Wenliang; Liu, Yuexia; Han, Tiancheng

    2016-09-01

    By using sub-wavelength resonators, metamaterial absorber shows great potential in many scientific and technical applications due to its perfect absorption characteristics. For most practical applications, the absorption bandwidth is one of the most important performance metrics. In this paper, we demonstrate the design of an ultra-broadband infrared absorber based on metasurface. Compared with the prior work [Opt. Express22(S7), A1713-A1724 (2014)], the proposed absorber shows more than twice the absorption bandwidth. The simulated total absorption exceeds 90% from 7.8 to 12.1 um and the full width at half maximum is 50% (from 7.5 to 12.5 μm), which is achieved by using a single layer of metasurface. Further study demonstrates that the absorption bandwidth can be greatly expanded by using two layers of metasurface, i.e. dual-layered absorber. The total absorption of the dual-layered absorber exceeds 80% from 5.2 to 13.7 um and the full width at half maximum is 95% (from 5.1 to 14.1 μm), much greater than those previously reported for infrared spectrum. The absorption decreases with fluctuations as the incident angle increases but remains quasi-constant up to relatively large angles. PMID:27607662

  8. Estimating the radiation absorbed by a human

    NASA Astrophysics Data System (ADS)

    Kenny, Natasha A.; Warland, Jon S.; Brown, Robert D.; Gillespie, Terry G.

    2008-07-01

    The complexities of the interactions between long- and short-wave radiation fluxes and the human body make it inherently difficult to estimate precisely the total radiation absorbed ( R) by a human in an outdoor environment. The purpose of this project was to assess and compare three methods to estimate the radiation absorbed by a human in an outdoor environment, and to compare the impact of applying various skin and clothing albedos ( α h ) on R. Field tests were conducted under both clear and overcast skies to evaluate the performance of applying a cylindrical radiation thermometer (CRT), net radiometer, and a theoretical estimation model to predict R. Three albedos were evaluated: light ( α h = 0.57), medium ( α h = 0.37), and dark ( α h = 0.21). During the sampling periods, the range of error between the methods used to estimate the radiation absorbed by a cylindrical body under clear and overcast skies ranged from 3 to 8%. Clothing and skin albedo had a substantial impact on R, with the mean change in R between the darkest and lightest albedos ranging from 115 to 157 W m - 2 over the sampling period. Radiation is one of the most important variables to consider in outdoor thermal comfort research, as R is often the largest contributor to the human energy balance equation. The methods outlined and assessed in this study can be conveniently applied to provide reliable estimates of the radiation absorbed by a human in an outdoor environment.

  9. Ultraviolet radiation absorbing compounds in marine organisms

    SciTech Connect

    Chalker, B.E.; Dunlap, W.C. )

    1990-01-09

    Studies on the biological effects of solar ultraviolet radiations are becoming increasingly common, in part due to recent interest in the Antarctic ozone hole and in the perceived potential for global climate change. Marine organisms possess many strategies for ameliorating the potentially damaging effects of UV-B (280-320 nm) and the shorter wavelengths of UV-A (320-400nm). One mechanism is the synthesis of bioaccumulation of ultraviolet radiation absorbing compounds. Several investigators have noted the presence of absorbing compounds in spectrophotometer scans of extracts from a variety of marine organisms, particularly algae and coelenterates containing endosymbiotic algae. The absorbing compounds are often mycosporine-like amino acids. Thirteen mycosporine-like amino acids have already been described, and several others have recently been detected. Although, the mycosporine-like amino acids are widely distributed. these compounds are by no means the only type of UV-B absorbing compounds which has been identified. Coumarins from green algae, quinones from sponges, and indoles from a variety of sources are laternative examples which are documented in the natural products literature. When the biological impact of solar ultraviolet radiation is assessed, adequate attention must be devoted to the process of photoadaptation, including the accumulation of ultraviolet radiation absorbing compounds.

  10. Design of integration-ready metasurface-based infrared absorbers

    SciTech Connect

    Ogando, Karim Pastoriza, Hernán

    2015-07-28

    We introduce an integration ready design of metamaterial infrared absorber, highly compatible with many kinds of fabrication processes. We present the results of an exhaustive experimental characterization, including an analysis of the effects of single meta-atom geometrical parameters and collective arrangement. We confront the results with the theoretical interpretations proposed in the literature. Based on the results, we develop a set of practical design rules for metamaterial absorbers in the infrared region.

  11. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Hodgson, Ed; Izenson, Mike; Chan, Weibo; Bue, Grant C.

    2012-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust nonventing system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s Lithium Chloride Absorber Radiator (LCAR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. This water vapor is then captured by solid LiCl in the LCAR with a high enthalpy of absorption, resulting in sufficient temperature lift to reject heat to space by radiation. After the sortie, the LCAR would be heated up and dried in a regenerator to drive off and recover the absorbed evaporant. A engineering development prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The LCAR was able to stably reject 75 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  12. Plasmonically enhanced thermomechanical detection of infrared radiation.

    PubMed

    Yi, Fei; Zhu, Hai; Reed, Jason C; Cubukcu, Ertugrul

    2013-04-10

    Nanoplasmonics has been an attractive area of research due to its ability to localize and manipulate freely propagating radiation on the nanometer scale for strong light-matter interactions. Meanwhile, nanomechanics has set records in the sensing of mass, force, and displacement. In this work, we report efficient coupling between infrared radiation and nanomechanical resonators through nanoantenna enhanced thermoplasmonic effects. Using efficient conversion of electromagnetic energy to mechanical energy in this plasmo-thermomechanical platform with a nanoslot plasmonic absorber integrated directly on a nanobeam mechanical resonator, we demonstrate room-temperature detection of nanowatt level power fluctuations in infrared radiation. We expect our approach, which combines nanoplasmonics with nanomechanical resonators, to lead to optically controlled nanomechanical systems enabling unprecedented functionality in biomolecular and toxic gas sensing and on-chip mass spectroscopy.

  13. Compensated infrared absorption sensor for carbon dioxide and other infrared absorbing gases

    DOEpatents

    Owen, Thomas E.

    2005-11-29

    A gas sensor, whose chamber uses filters and choppers in either a semicircular geometry or annular geometry, and incorporates separate infrared radiation filters and optical choppers. This configuration facilitates the use of a single infrared radiation source and a single detector for infrared measurements at two wavelengths, such that measurement errors may be compensated.

  14. Electromagnetic radiation absorbers and modulators comprising polyaniline

    DOEpatents

    Epstein, Arthur J.; Ginder, John M.; Roe, Mitchell G.; Hajiseyedjavadi, Hamid

    1992-01-01

    A composition for absorbing electromagnetic radiation, wherein said electromagnetic radiation possesses a wavelength generally in the range of from about 1000 Angstroms to about 50 meters, wherein said composition comprises a polyaniline composition of the formula ##STR1## where y can be equal to or greater than zero, and R.sup.1 and R.sup.2 are independently selected from the group containing of H, --OCH.sub.3, --CH.sub.3, --F, --Cl, --Br, --I, NR.sup.3 .sub.2, --NHCOR.sup.3, --OH, --O.sup.-, SR.sup.3, --OCOR.sup.3, --NO.sub.2, --COOH, --COOR.sup.3, --COR.sup.3, --CHO, and --CN, where R.sup.3 is a C.sub.1 to C.sub.8 alkyl, aryl or aralkyl group.

  15. Remote infrared radiation detection using piezoresistive microcantilevers

    SciTech Connect

    Datskos, P.G.; Oden, P.I.; Thundat, T.; Wachter, E.A.; Warmack, R.J.; Hunter, S.R.

    1996-11-01

    A novel micromechanical infrared (IR) radiation sensor has been developed using commercially available piezoresistive microcantilevers. Microcantilevers coated with a heat absorbing layer undergo bending due to the differential stress between the top layer (coating) and the substrate. The bending causes a change in the piezoresistance and is proportional to the amount of heat absorbed. The microcantilever IR sensor exhibits two distinct thermal responses: a fast one ({lt}ms) and a slower one ({approximately}10 ms). A noise equivalent power (at a modulation frequency of 30 Hz) was estimated to be {approximately}70 nW/Hz{sup 1/2}. This value can be further reduced by designing microcantilevers with better thermal isolation that can allow microcantilevers to be used as uncooled IR radiation detectors. {copyright} {ital 1996 American Institute of Physics.}

  16. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Hodgson, Ed; Izenso, Mike; Chan, Weibo; Cupples, Scott

    2011-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust non-venting system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's lithium chloride Heat Pump Radiator (HPR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. The SEAR is evacuated at the onset of operations and thereafter, the water vapor absorption rate of the HPR maintains a low pressure environment for the SWME to evaporate effectively. This water vapor captured by solid LiCl in the HPR with a high enthalpy of absorption, results in sufficient temperature lift to reject most of the heat to space by radiation. After the sortie, the HPR would be heated up in a regenerator to drive off and recover the absorbed evaporant. A one-fourth scale prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The HPR was able to stably reject 60 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  17. Space Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Stephan, Ryan; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2012-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 m2 radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduces the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  18. Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2013-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 sq m radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduce the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  19. Band models and correlations for infrared radiation

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.

    1975-01-01

    Absorption of infrared radiation by various line and band models are briefly reviewed. Narrow band model relations for absorptance are used to develop 'exact' formulations for total absorption by four wide band models. Application of a wide band model to a particular gas largely depends upon the spectroscopic characteristic of the absorbing-emitting molecule. Seven continuous correlations for the absorption of a wide band model are presented and each one of these is compared with the exact (numerical) solutions of the wide band models. Comparison of these results indicate the validity of a correlation for a particular radiative transfer application. In radiative transfer analyses, use of continuous correlations for total band absorptance provides flexibilities in various mathematical operations.

  20. A Broadband Micro-Machined Far-Infrared Absorber

    NASA Technical Reports Server (NTRS)

    Wollack, E. J.; Datesman, A. M.; Jhabvala, C. A.; Miller, K. H.; Quijada, M. A.

    2016-01-01

    The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is greater than 0.95 from 1 to 20 terahertz (300-15 microns) over a temperature range spanning 5-300 degrees Kelvin. The meta-material, realized from an array of tapers approximately 100 microns in length, is largely insensitive to the detailed geometry of these elements and is cryogenically compatible with silicon-based micro-machined technologies. The electromagnetic response is in general agreement with a physically motivated transmission line model.

  1. A broadband micro-machined far-infrared absorber.

    PubMed

    Wollack, E J; Datesman, A M; Jhabvala, C A; Miller, K H; Quijada, M A

    2016-05-01

    The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is >0.95 from 1 to 20 THz (300-15 μm) over a temperature range spanning 5-300 K. The meta-material, realized from an array of tapers ≈100 μm in length, is largely insensitive to the detailed geometry of these elements and is cryogenically compatible with silicon-based micro-machined technologies. The electromagnetic response is in general agreement with a physically motivated transmission line model. PMID:27250445

  2. A broadband micro-machined far-infrared absorber

    NASA Astrophysics Data System (ADS)

    Wollack, E. J.; Datesman, A. M.; Jhabvala, C. A.; Miller, K. H.; Quijada, M. A.

    2016-05-01

    The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is >0.95 from 1 to 20 THz (300-15 μm) over a temperature range spanning 5-300 K. The meta-material, realized from an array of tapers ≈100 μm in length, is largely insensitive to the detailed geometry of these elements and is cryogenically compatible with silicon-based micro-machined technologies. The electromagnetic response is in general agreement with a physically motivated transmission line model.

  3. Micro-electro-mechanically switchable near infrared complementary metamaterial absorber

    SciTech Connect

    Pitchappa, Prakash; Pei Ho, Chong; Kropelnicki, Piotr; Singh, Navab; Kwong, Dim-Lee; Lee, Chengkuo

    2014-05-19

    We experimentally demonstrate a micro-electro-mechanically switchable near infrared complementary metamaterial absorber by integrating the metamaterial layer to be the out of plane movable microactuator. The metamaterial layer is electrostatically actuated by applying voltage across the suspended complementary metamaterial layer and the stationary bottom metallic reflector. Thus, the effective spacing between the metamaterial layer and bottom metal reflector is varied as a function of applied voltage. With the reduction of effective spacing between the metamaterial and reflector layers, a strong spectral blue shift in the peak absorption wavelength can be achieved. With spacing change of 300 nm, the spectral shift of 0.7 μm in peak absorption wavelength was obtained for near infrared spectral region. The electro-optic switching performance of the device was characterized, and a striking switching contrast of 1500% was achieved at 2.1 μm. The reported micro-electro-mechanically tunable complementary metamaterial absorber device can potentially enable a wide range of high performance electro-optical devices, such as continuously tunable filters, modulators, and electro-optic switches that form the key components to facilitate future photonic circuit applications.

  4. Pigments which reflect infrared radiation from fire

    DOEpatents

    Berdahl, P.H.

    1998-09-22

    Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer ({micro}m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 {micro}m or, for cool smoky fires, about 2 {micro}m to about 16 {micro}m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 {micro}m to about 2 {micro}m and thin leafing aluminum flake pigments. 4 figs.

  5. Pigments which reflect infrared radiation from fire

    DOEpatents

    Berdahl, Paul H.

    1998-01-01

    Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer (.mu.m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 .mu.m or, for cool smoky fires, about 2 .mu.m to about 16 .mu.m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 .mu.m to about 2 .mu.m and thin leafing aluminum flake pigments.

  6. Fabrication of metasurface-based infrared absorber structures using direct laser write lithography

    NASA Astrophysics Data System (ADS)

    Fanyaeu, Ihar; Mizeikis, Vygantas

    2016-03-01

    We report fabrication and optical properties of ultra-thin polarization-invariant electromagnetic absorber metasurface for infra-red spectral. The absorber structure, which uses three-dimensional architecture is based on single-turn metallic helices arranged into a periodic square lattice on a metallic substrate, is expected to exhibit total resonant absorption due to balanced coupling between resonances of the helices. The structure was designed using numerical simulations aiming to tune the total absorption resonance to infra-red wavelength range by appropriately downscaling the unit cell of the structure, and taking into account dielectric dispersion and losses of the metal. The designed structures were subsequently fabricated using femtosecond direct laser write technique in a dielectric photoresist, and subsequent metallisation by gold sputtering. In accordance with the expectations, the structure was found to exhibit resonant absorption centred near the wavelength of 6 - 9 µm, with peak absorption in excess of 82%. The absorber metasurface may be applied in various areas of science and technology, such as harvesting infra-red radiation in thermal detectors and energy converters.

  7. Diffuse Cosmic Infrared Background Radiation

    NASA Technical Reports Server (NTRS)

    Dwek, Eli

    2002-01-01

    The diffuse cosmic infrared background (CIB) consists of the cumulative radiant energy released in the processes of structure formation that have occurred since the decoupling of matter and radiation following the Big Bang. In this lecture I will review the observational data that provided the first detections and limits on the CIB, and the theoretical studies explaining the origin of this background. Finally, I will also discuss the relevance of this background to the universe as seen in high energy gamma-rays.

  8. Flexible metamaterial absorbers with multi-band infrared response

    NASA Astrophysics Data System (ADS)

    Dayal, Govind; Ramakrishna, S. Anantha

    2015-01-01

    A flexible metamaterial with a tri-layer metal-dielectric-metal structure is fabricated by combining Excimer laser micromachining of a polyimide sheet and oblique angle physical vapour deposition methods. Excimer laser micromachining is used to generate an array of micro-disks on the flexible polymer sheet followed by physical vapour deposition at normal incidence to produce continuous metal and dielectric layers while oblique angle deposition of metal vapour is used to finally form discrete oblate ellipsoids on top of the micro-disks. The fabricated metamaterial shows multi-band metamaterial absorption exceeding 90% simultaneously over infrared bands centred at 3 µm, 5 µm, and 13.85 µm. The multi-band absorption arises due to multipole resonances of the disk structure and is accurately modelled by electromagnetic simulation as well. A theoretical model of a perfect absorber as an array of optimally impedance matched antennas is also presented.

  9. Near-infrared absorbing semitransparent organic solar cells

    NASA Astrophysics Data System (ADS)

    Meiss, Jan; Holzmueller, Felix; Gresser, Roland; Leo, Karl; Riede, Moritz

    2011-11-01

    We present efficient, semitransparent small molecule organic solar cells. The devices employ an indium tin oxide-free top contact, consisting of thin metal films and an additional organic capping layer for enhanced light in/outcoupling. The solar cell encorporates a bulk heterojunction with the donor material Ph2-benz-bodipy, an infrared absorber. Combination of Ph2-benz-bodipy with C60 as acceptor leads to devices with high open circuit voltages of up to 0.81 V and short circuit current densities of 5-6 mA/cm2, resulting in efficiences of 2.2%-2.5%. At the same time, the devices are highly transparent, with an average transmittance in the visible range (400-750 nm) of up to 47.9%, with peaks at 538 nm of up to 64.2% and an average transmittance in the yellow-green range of up to 61.8%.

  10. Dual-band near-infrared plasmonic perfect absorber assisted by strong coupling between bright-dark nanoresonators

    NASA Astrophysics Data System (ADS)

    Lian, Yudong; Ren, Guobin; Liu, Huaiqing; Gao, Yixiao; Zhu, Bofeng; Wu, Beilei; Jian, Shuisheng

    2016-12-01

    In this paper, a plasmonic structure with subwavelength air groove periodically etched on metallic surface is designed and numerically investigated by using Finite Element Method (FEM). The simulation results reveal that the transverse magnetic (TM) polarized incident wave can be perfectly absorbed by the air grooves due to the metallic ohmic loss of Fabry-Pérot resonance. More importantly, by introducing an additional nanoresonator to form a pair of bright-dark resonators, a dual-band plasmonic nearly-perfect absorber can be achieved and the original single absorption peak splits into two absorption peaks. Moreover, the resonance wavelengths correspond to the absorption peaks can be manipulated by varying the geometric parameters. Furthermore, the proposed absorber is found to have large angle tolerance. This dual-band and angle independent near-infrared plasmonic perfect absorber has potential applications in infrared technology and devices, such as imaging devices, thermal bolometers, solar cells and wavelength selective radiators.

  11. Porphyrin Based Near Infrared-Absorbing Materials for Organic Photovoltaics

    NASA Astrophysics Data System (ADS)

    Zhong, Qiwen

    The conservation and transformation of energy is essential to the survival of mankind, and thus concerns every modern society. Solar energy, as an everlasting source of energy, holds one of the key solutions to some of the most urgent problems the world now faces, such as global warming and the oil crisis. Advances in technologies utilizing clean, abundant solar energy, could be the steering wheel of our societies. Solar cells, one of the major advances in converting solar energy into electricity, are now capturing people's interest all over the globe. While solar cells have been commercially available for many years, the manufacturing of solar cells is quite expensive, limiting their broad based implementation. The cost of solar cell based electricity is 15-50 cents per kilowatt hour (¢/kwh), depending on the type of solar cell, compared to 0.7 ¢/kwh for fossil fuel based electricity. Clearly, decreasing the cost of electricity from solar cells is critical for their wide spread deployment. This will require a decrease in the cost of light absorbing materials and material processing used in fabricating the cells. Organic photovoltaics (OPVs) utilize organic materials such as polymers and small molecules. These devices have the advantage of being flexible and lower cost than conventional solar cells built from inorganic semiconductors (e.g. silicon). The low cost of OPVs is tied to lower materials and fabrication costs of organic cells. However, the current power conversion efficiencies of OPVs are still below 15%, while convention crystalline Si cells have efficiencies of 20-25%. A key limitation in OPVs today is their inability to utilize the near infrared (NIR) portion of the solar spectrum. This part of the spectrum comprises nearly half of the energy in sunlight that could be used to make electricity. The first and foremost step in conversion solar energy conversion is the absorption of light, which nature has provided us optimal model of, which is

  12. Infrared Radiative Properties of Food Materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precisely, infrared radiation is electromagnetic radiation whose wavelength is longer than that of visible light, but shorter than that of terahertz radiation and microwaves. The infrared portion of the electromagnetic spectrum spans roughly three orders of magnitude (750 nm to 100 µm) and has been...

  13. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    NASA Technical Reports Server (NTRS)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  14. Models for infrared atmospheric radiation

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.

    1976-01-01

    Line and band models for infrared spectral absorption are discussed. Radiative transmittance and integrated absorptance of Lorentz, Doppler, and voigt line profiles were compared for a range of parameters. It was found that, for the intermediate path lengths, the combined Lorentz-Doppler (Voigt) profile is essential in calculating the atmospheric transmittance. Narrow band model relations for absorptance were used to develop exact formulations for total absorption by four wide band models. Several continuous correlations for the absorption of a wide band model were compared with the numerical solutions of the wide band models. By employing the line-by-line and quasi-random band model formulations, computational procedures were developed for evaluating transmittance and upwelling atmospheric radiance. Homogeneous path transmittances were calculated for selected bands of CO, CO2, and N2O and compared with experimental measurements. The upwelling radiance and signal change in the wave number interval of the CO fundamental band were also calculated.

  15. Performance of a Multifunctional Space Evaporator- Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Bue, Grant; Quinn, Gregory

    2013-01-01

    The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 sq ft prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable heat rejection from the LCAR.

  16. Performance of a Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection sufficient for most EVA activities by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 ft² prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable rejection of metabolic heat from the LCAR. We used results of these tests to assess future performance potential and suggest approaches for integrating the SEAR system with future space suits.

  17. Spectral estimators of absorbed photosynthetically active radiation in corn canopies

    NASA Technical Reports Server (NTRS)

    Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

    1984-01-01

    Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a LANDSAT MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95% of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50% of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73% of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

  18. Spectral estimators of absorbed photosynthetically active radiation in corn canopies

    NASA Technical Reports Server (NTRS)

    Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

    1985-01-01

    Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a Landsat MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95 percent of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50 percent of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73 percent of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

  19. Global warming due to increasing absorbed solar radiation

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Fasullo, John T.

    2009-04-01

    Global climate models used in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) are examined for the top-of-atmosphere radiation changes as carbon dioxide and other greenhouse gases build up from 1950 to 2100. There is an increase in net radiation absorbed, but not in ways commonly assumed. While there is a large increase in the greenhouse effect from increasing greenhouse gases and water vapor (as a feedback), this is offset to a large degree by a decreasing greenhouse effect from reducing cloud cover and increasing radiative emissions from higher temperatures. Instead the main warming from an energy budget standpoint comes from increases in absorbed solar radiation that stem directly from the decreasing cloud amounts. These findings underscore the need to ascertain the credibility of the model changes, especially insofar as changes in clouds are concerned.

  20. Absorbed radiation by various tissues during simulated endodontic radiography

    SciTech Connect

    Torabinejad, M.; Danforth, R.; Andrews, K.; Chan, C.

    1989-06-01

    The amount of absorbed radiation by various organs was determined by placing lithium fluoride thermoluminescent chip dosimeters at selected anatomical sites in and on a human-like X-ray phantom and exposing them to radiation at 70- and 90-kV X-ray peaks during simulated endodontic radiography. The mean exposure dose was determined for each anatomical site. The results show that endodontic X-ray doses received by patients are low when compared with other radiographic procedures.

  1. Performance enhancement of uncooled infrared focal plane array by integrating metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Ma, Wei; Wen, Yongzheng; Yu, Xiaomei; Feng, Yun; Zhao, Yuejin

    2015-03-01

    This letter presents an infrared (IR) focal plane array (FPA) with metamaterial absorber (MMA) integrated to enhance its performance. A glass substrate, on which arrays of bimaterial cantilevers are fabricated as the thermal-sensitive pixels by a polyimide surface sacrificial process, is employed to allow the optical readout from the back side of the substrate. Whereas the IR wave radiates onto the FPA from the front side, which consequently avoids the energy loss caused by the silicon substrate compared with the previous works. This structure also facilitates the integration of MMA by introducing a layer of periodic square resonators atop the SiNx structural layer to form a metal/dielectric/metal stack with the gold mirror functioning as the ground plane. A comparative experiment was carried out on the FPAs that use MMA and ordinary SiNx as the absorbers, respectively. The performance improvement was verified by the evaluation of the absorbers as well as the imaging results of both FPAs.

  2. Performance enhancement of uncooled infrared focal plane array by integrating metamaterial absorber

    SciTech Connect

    Ma, Wei; Wen, Yongzheng; Yu, Xiaomei

    2015-03-16

    This letter presents an infrared (IR) focal plane array (FPA) with metamaterial absorber (MMA) integrated to enhance its performance. A glass substrate, on which arrays of bimaterial cantilevers are fabricated as the thermal-sensitive pixels by a polyimide surface sacrificial process, is employed to allow the optical readout from the back side of the substrate. Whereas the IR wave radiates onto the FPA from the front side, which consequently avoids the energy loss caused by the silicon substrate compared with the previous works. This structure also facilitates the integration of MMA by introducing a layer of periodic square resonators atop the SiN{sub x} structural layer to form a metal/dielectric/metal stack with the gold mirror functioning as the ground plane. A comparative experiment was carried out on the FPAs that use MMA and ordinary SiN{sub x} as the absorbers, respectively. The performance improvement was verified by the evaluation of the absorbers as well as the imaging results of both FPAs.

  3. Measurement of radiation property of long infrared emitter and examination of infrared radiation heating process

    NASA Astrophysics Data System (ADS)

    Nakano, Y.; Miyanaga, T.; Miyakawa, M.

    1989-05-01

    Long infrared radiation is becoming widely used for process heating, drying and space heating. In order to make more effective use of long infrared radiation, the investigations on measuring method of radiation property of long infrared emitter, the measuring results, and selection of suitable emitters for heating objects, were carried out. Using Fourier transform infrared radiation spectrophotometer, trial manufacture of an apparatus for measuring spectral emissivity of long infrared emitters was conducted and the measuring method was established. By this, the following knowledges on ceramic long infrared emitter were obtained: spectral emissivity almost never depends on temperature of the emitter, variation with time is hardly shown, and radiation efficiency is shown to be 50 to 60 percent. Infrared radiation heating processes on foods and synthetic resins were investigated, and an examination on the method for selecting emitters, which are suitable to materials to be heated, was conducted.

  4. Thermal radiation absorbed by dairy cows in pasture

    NASA Astrophysics Data System (ADS)

    da Silva, Roberto Gomes; Guilhermino, Magda Maria; de Morais, Débora Andréia E. Façanha

    2010-01-01

    The goal of the present paper was to assess a method for estimating the thermal radiation absorbed by dairy cows (0.875 Holstein-0.125 Guzerath) on pasture. A field test was conducted with 472 crossbred dairy cows in three locations of a tropical region. The following environmental data were collected: air temperature, partial vapour pressure, wind speed, black globe temperature, ground surface temperature and solar radiation. Average total radiation absorbed by animals was calculated as {R_{abs}} = 640.0 ± 3.1 W.{m^{ - 2}} . Absorbed short-wave radiation (solar direct, diffuse and reflected) averaged 297.9 ± 2.7 W m-2; long wave (from the sky and from terrestrial surfaces) averaged 342.1 ± 1.5 W m-2. It was suggested that a new environmental measurement, the effective radiant heat load (ERHL), could be used to assess the effective mean radiant temperature ( {T_{mr}^* } ) . Average T_{mr}^* was 101.4 ± 1.2°C, in contrast to the usual mean radiant temperature, {T_{mr}} = 65.1 ± 0.5° C . Estimates of T_{mr}^* were considered as more reliable than those of T mr in evaluating the thermal environment in the open field, because T mr is almost totally associated only with long wave radiation.

  5. Radiation in an Emitting and Absorbing Medium: A Gridless Approach

    SciTech Connect

    GRITZO,LOUIS A.; STRICKLAND,JAMES H.; DESJARDIN,PAUL E.

    2000-07-27

    A gridless technique for the solution of the integral form of the radiative heat flux equation for emitting and absorbing media is presented. Treatment of non-uniform absorptivity and gray boundaries is included. As part of this work, the authors have developed fast multipole techniques for extracting radiative heat flux quantities from the temperature fields of one-dimensional and three-dimensional geometries. Example calculations include those for one-dimensional radiative heat transfer through multiple flame sheets, a three-dimensional enclosure with black walls, and an axisymmetric enclosure with black walls.

  6. Dry Process Based Infrared Sensors with CNT Film Absorber

    NASA Astrophysics Data System (ADS)

    Yoo, Kum-Pyo; Hong, Hyun Pyo; Lim, Lee-Taek; Choi, Chang-Seon; Lee, Dong Il; Lee, Cheol Jin; Park, Chan-Won; Min, Nam Ki

    In this paper, we describe the fabrication and characterization of a front-side micromachined thermopiles consisting of a suspended membrane and a carbon nanotube (CNT) film absorber. Thermocouples of 52 pairs which are composed of phosphorous-doped silicon and aluminum were formed and connected in series. A CNT film collected by filter was transferred on hot junction. A CNT absorber has an absorptance of about 50% in the midinfrared region. The suspended membrane was fabricated by an isotropic silicon dry etching process with XeF2 gas at the front side of the substrates. The output voltage with the CNT film is found to be 250.2 mV at 7 mW of incident power, approximately 1.8 times higher than that of one without an absorber.

  7. Prediction of multiple resonance characteristics by an extended resistor-inductor-capacitor circuit model for plasmonic metamaterials absorbers in infrared.

    PubMed

    Xu, Xiaolun; Li, Yongqian; Wang, Binbin; Zhou, Zili

    2015-10-01

    The resonance characteristics of plasmonic metamaterials absorbers (PMAs) are strongly dependent on geometric parameters. A resistor-inductor-capacitor (RLC) circuit model has been extended to predict the resonance wavelengths and the bandwidths of multiple magnetic polaritons modes in PMAs. For a typical metallic-dielectric-metallic structure absorber working in the infrared region, the developed model describes the correlation between the resonance characteristics and the dimensional sizes. In particular, the RLC model is suitable for not only the fundamental resonance mode, but also for the second- and third-order resonance modes. The prediction of the resonance characteristics agrees fairly well with those calculated by the finite-difference time-domain simulation and the experimental results. The developed RLC model enables the facilitation of designing multi-band PMAs for infrared radiation detectors and thermal emitters. PMID:26421549

  8. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  9. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and adaptability to highly variable thermal environments. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flightlike, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  10. Frequency Integrated Radiation Models for Absorbing and Scattering Media

    NASA Technical Reports Server (NTRS)

    Ripoll, J. F.; Wray, A. A.

    2004-01-01

    The objective of this work is to contribute to the simplification of existing radiation models used in complex emitting, absorbing, scattering media. The application in view is the computation of flows occurring in such complex media, such as certain stellar interiors or combusting gases. In these problems, especially when scattering is present, the complexity of the radiative transfer leads to a high numerical cost, which is often avoided by simply neglecting it. The complexity lies partly in the strong dependence of the spectral coefficients on frequency. Models are then needed to capture the effects of the radiation when one cannot afford to directly solve for it. In this work, the frequency dependence will be modeled and integrated out in order retain only the average effects. A frequency-integrated radiative transfer equation (RTE) will be derived.

  11. Infrared receiver having a cooled radiation detector

    SciTech Connect

    Van Antwerpen, H. C.

    1985-04-09

    An infrared receiver having an infrared radiation detector cooled by means of a cold-gas engine, the thermal contact between a cooling surface of the cold-gas engine and the radiation detector being obtained by an elastic thermally conducting bridge. The cylindrical bridge is comprised of a plurality of turns of a metal strip. Due to the presence of the bridge, a good thermal conduction and further a compensation for differences in thermal expansion coefficients of the materials used are obtained. The infrared receiver is particularly suitable for night vision apparatus.

  12. Improved source of infrared radiation for spectroscopy

    NASA Technical Reports Server (NTRS)

    Burkhard, D. G.; Rao, K. N.

    1971-01-01

    Radiation from a crimped V-groove in the electrically heated metallic element of a high-resolution infrared spectrometer is more intense than that from plane areas adjacent to the element. Radiation from the vee and the flat was compared by alternately focusing on the entrance slit of a spectrograph.

  13. Radiation environments and absorbed dose estimations on manned space missions

    NASA Astrophysics Data System (ADS)

    Curtis, S. B.; Atwell, W.; Beever, R.; Hardy, A.

    In order to make an assessment of radiation risk during manned missions in space, it is necessary first to have as accurate an estimation as possible of the radiation environment within the spacecraft to which the astronauts will be exposed. Then, with this knowledge and the inclusion of body self-shielding, estimations can be made of absorbed doses for various body organs (skin, eye, blood-forming organs, etc.). A review is presented of our present knowledge of the radiation environments and absorbed doses expected for several space mission scenarios selected for our development of the new radiation protection guidelines. The scenarios selected are a 90-day mission at an altitude (450 km) and orbital inclinations (28.5°, 57° and 90°) appropriate for NASA's Space Station, a 15-day sortie to geosynchronous orbit and a 90-day lunar mission. All scenarios chosen yielded dose equivalents between five and ten rem to the blood forming organs if no large solar particle event were encountered. Such particle events could add considerable exposure particularly to the skin and eye for all scenarios except the one at 28.5° orbital inclination.

  14. Coherent tunable far infrared radiation

    NASA Technical Reports Server (NTRS)

    Jennings, D. A.

    1989-01-01

    Tunable, CW, FIR radiation has been generated by nonlinear mixing of radiation from two CO2 lasers in a metal-insulator-metal (MIM) diode. The FIR difference-frequency power was radiated from the MIM diode antenna to a calibrated InSb bolometer. FIR power of 200 nW was generated by 250 mW from each of the CO2 lasers. Using the combination of lines from a waveguide CO2 laser, with its larger tuning range, with lines from CO2, N2O, and CO2-isotope lasers promises complete coverage of the entire FIR band with stepwise-tunable CW radiation.

  15. Propagation of an electromagnetic wave in an absorbing anisotropic medium and infrared transmission of liquid crystals: comparison with experiments.

    PubMed

    Scaife, B K P; Sigarev, A A; Vij, J K; Goodby, J W

    2009-08-01

    The theory of the absorbance of a semi-infinite medium characterized by a second-rank dielectric tensor for the entire electromagnetic spectrum, as given by Scaife and Vij [J. Chem. Phys. 122, 174901 (2005)], is extended to include molecules of prolate spheriodal shape with longitudinal and transverse polarizabilities and to cover the case of elliptically polarized incident radiation. The theory is applied to the infrared transmission experiments of biaxial liquid crystals. It is found that the formula for the dependence on frequency and on angle of polarization of the absorbance A(omega,theta)= -log(10)[10(A(omega,0)) cos(2) theta + (10(-A(omega,pi/2)) sin(2) theta)] is unaffected by the anisotropy of the molecules and by the elliptical polarization of the incident radiation. A small (+/-5%) discrepancy between theory and experiment has been found for bands with high absorbances. It is found that this discrepancy does not depend on birefringence of the sample but may depend on the precise method of absorbance measurement and on effects at the surface of the cell containing the liquid crystal under test.

  16. Transition undulator radiation as bright infrared sources

    SciTech Connect

    Kim, K.J.

    1995-02-01

    Undulator radiation contains, in addition to the usual component with narrow spectral features, a broad-band component in the low frequency region emitted in the near forward direction, peaked at an angle 1/{gamma}, where {gamma} is the relativistic factor. This component is referred to as the transition undulator radiation, as it is caused by the sudden change in the electron`s longitudinal velocity as it enters and leaves the undulator. The characteristic of the transition undulator radiation are analyzed and compared with the infrared radiation from the usual undulator harmonics and from bending magnets.

  17. Space radiation absorbed dose distribution in a human phantom.

    PubMed

    Badhwar, G D; Atwell, W; Badavi, F F; Yang, T C; Cleghorn, T F

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  18. Space radiation absorbed dose distribution in a human phantom

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Atwell, W.; Badavi, F. F.; Yang, T. C.; Cleghorn, T. F.

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  19. Space radiation absorbed dose distribution in a human phantom.

    PubMed

    Badhwar, G D; Atwell, W; Badavi, F F; Yang, T C; Cleghorn, T F

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  20. Design of mid-infrared ultra-wideband metallic absorber based on circuit theory

    NASA Astrophysics Data System (ADS)

    Arik, Kamalodin; Abdollahramezani, Sajjad; Farajollahi, Saeed; Khavasi, Amin; Rejaei, Behzad

    2016-12-01

    An ultra-broadband absorber of light is proposed by using periodic array of ultra-thin metallic ribbons on top of a lossless quarter-wavelength dielectric spacer placed on a metallic reflector. We propose a fully analytical circuit model for the structure, and then the absorber is duly designed based on the impedance matching concept. As a result, normalized bandwidth of 99.5% is realized by the proposed absorbing structure in mid-infrared regime. Performing a numerical optimization algorithm, we could also reach to normalized bandwidth of 103%.

  1. Aqueous infrared carboxylate absorbances: Aliphatic di-acids

    USGS Publications Warehouse

    Cabaniss, S.E.; Leenheer, J.A.; McVey, I.F.

    1998-01-01

    Aqueous attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra of 18 aliphatic di-carboxylic acids are reported as a function of pH. The spectra show isosbestic points and intensity changes which indicate that Beer's law is obeyed, and peak frequencies lie within previously reported ranges for aqueous carboxylates and pure carboxylic acids. Intensity sharing from the symmetric carboxylate stretch is evident in many cases, so that bands which are nominally due to alkyl groups show increased intensity at higher pH. The asymmetric stretch of the HA- species is linearly related to the microscopic acidity constant of the H2A species, with ??pK 2 intervening atoms). The results suggest that aqueous ATR-FTIR may be able to estimate 'intrinsic' pKa values of carboxylic acids, in addition to providing quantitative estimates of ionization. ?? 1998 Elsevier Science B.V. All rights reserved.

  2. Thin-film, wide-angle, design-tunable, selective absorber from near UV to far infrared

    NASA Astrophysics Data System (ADS)

    Nath, Janardan; Maukonen, Douglas; Smith, Evan; Figueiredo, Pedro; Zummo, Guy; Panjwani, Deep; Peale, Robert E.; Boreman, Glenn; Cleary, Justin W.; Eyink, Kurt

    2013-06-01

    We experimentally demonstrate a structured thin film that selectively absorbs incident electromagnetic waves in discrete bands, which by design occur in any chosen range from near UV to far infrared. The structure consists of conducting islands separated from a conducting plane by a dielectric layer. By changing dimensions and materials, we have achieved broad absorption resonances centered at 0.36, 1.1, 14, and 53 microns wavelength. Angle-dependent specular reflectivity spectra are measured using UV-visible or Fourier spectrometers. The peak absorption ranges from 85 to 98%. The absorption resonances are explained using the model of an LCR resonant circuit created by coupling between dipolar plasma resonance in the surface structures and their image dipoles in the ground plane. The resonance wavelength is proportional to the dielectric permittivity and to the linear dimension of the surface structures. These absorbers have application to thermal detectors of electromagnetic radiation.

  3. Wedge immersed thermistor bolometer measures infrared radiation

    NASA Technical Reports Server (NTRS)

    Dreyfus, M. G.

    1965-01-01

    Wedge immersed-thermistor bolometer measures infrared radiation in the atmosphere. The thermistor flakes are immersed by optical contact on a wedge-shaped germanium lens whose narrow dimension is clamped between two complementary wedge-shaped germanium blocks bonded with a suitable adhesive.

  4. Conformal dual-band near-perfectly absorbing mid-infrared metamaterial coating.

    PubMed

    Jiang, Zhi Hao; Yun, Seokho; Toor, Fatima; Werner, Douglas H; Mayer, Theresa S

    2011-06-28

    Metamaterials offer a new approach to create surface coatings with highly customizable electromagnetic absorption from the microwave to the optical regimes. Thus far, efficient metamaterial absorbers have been demonstrated at microwave frequencies, with recent efforts aimed at much shorter terahertz and infrared wavelengths. The present infrared absorbers have been constructed from arrays of nanoscale metal resonators with simple circular or cross-shaped geometries, which provide a single band response. In this paper, we demonstrate a conformal metamaterial absorber with a narrow band, polarization-independent absorptivity of >90% over a wide ±50° angular range centered at mid-infrared wavelengths of 3.3 and 3.9 μm. The highly efficient dual-band metamaterial was realized by using a genetic algorithm to identify an array of H-shaped nanoresonators with an effective electric and magnetic response that maximizes absorption in each wavelength band when patterned on a flexible Kapton and Au thin film substrate stack. This conformal metamaterial absorber maintains its absorption properties when integrated onto curved surfaces of arbitrary materials, making it attractive for advanced coatings that suppress the infrared reflection from the protected surface. PMID:21456579

  5. Conformal dual-band near-perfectly absorbing mid-infrared metamaterial coating.

    PubMed

    Jiang, Zhi Hao; Yun, Seokho; Toor, Fatima; Werner, Douglas H; Mayer, Theresa S

    2011-06-28

    Metamaterials offer a new approach to create surface coatings with highly customizable electromagnetic absorption from the microwave to the optical regimes. Thus far, efficient metamaterial absorbers have been demonstrated at microwave frequencies, with recent efforts aimed at much shorter terahertz and infrared wavelengths. The present infrared absorbers have been constructed from arrays of nanoscale metal resonators with simple circular or cross-shaped geometries, which provide a single band response. In this paper, we demonstrate a conformal metamaterial absorber with a narrow band, polarization-independent absorptivity of >90% over a wide ±50° angular range centered at mid-infrared wavelengths of 3.3 and 3.9 μm. The highly efficient dual-band metamaterial was realized by using a genetic algorithm to identify an array of H-shaped nanoresonators with an effective electric and magnetic response that maximizes absorption in each wavelength band when patterned on a flexible Kapton and Au thin film substrate stack. This conformal metamaterial absorber maintains its absorption properties when integrated onto curved surfaces of arbitrary materials, making it attractive for advanced coatings that suppress the infrared reflection from the protected surface.

  6. Near-infrared radiation curable multilayer coating systems and methods for applying same

    DOEpatents

    Bowman, Mark P; Verdun, Shelley D; Post, Gordon L

    2015-04-28

    Multilayer coating systems, methods of applying and related substrates are disclosed. The coating system may comprise a first coating comprising a near-IR absorber, and a second coating deposited on a least a portion of the first coating. Methods of applying a multilayer coating composition to a substrate may comprise applying a first coating comprising a near-IR absorber, applying a second coating over at least a portion of the first coating and curing the coating with near infrared radiation.

  7. Fabrication and Numerical Characterization of Infrared Metamaterial Absorbers for Refractometric Biosensors

    NASA Astrophysics Data System (ADS)

    Le, Khai Q.; Bai, Jing; Ngo, Quang Minh; Chen, Pai-Yen

    2016-10-01

    We report the successful fabrication of infrared plasmonic metamaterial absorbers by electron beam lithography and the lift-off technique. The absorber consists of periodic arrays of gold (Au) nanostructures deposited on a stack of thin silica spacer and gold film (acting as a mirror) on a silicon wafer. At resonance, we numerically observed a strong field enhancement between the metallic nanostructures and the Au film, resulting in a strong confinement of incident light within the silica spacer and thus a high absorption of up to 80% at infrared wavelengths. Our experimental measurement for reflection coefficients are in excellent agreement with the full-wave simulation results. We show that the resonant absorption spectral response can be used for highly-sensitive, label-free refractive-index biosensors. By tailoring various forms of nanostructures, we investigate their refractive index sensitivities to identity the most sensitive sensor at specific infrared wavelengths.

  8. Infrared microspectroscopy with synchrotron radiation

    SciTech Connect

    Carr, G.L.; Williams, G.P.

    1997-09-01

    Infrared microspectroscopy with a high brightness synchrotron source can achieve a spatial resolution approaching the diffraction limit. However, in order to realize this intrinsic source brightness at the specimen location, some care must be taken in designing the optical system. Also, when operating in diffraction limited conditions, the effective spatial resolution is no longer controlled by the apertures typically used for a conventional (geometrically defined) measurement. Instead, the spatial resolution depends on the wavelength of light and the effective apertures of the microscope`s Schwarzchild objectives. The authors have modeled the optical system from the synchrotron source up to the sample location and determined the diffraction-limited spatial distribution of light. Effects due to the dependence of the synchrotron source`s numerical aperture on wavelength, as well as the difference between transmission and reflection measurement modes, are also addressed. Lastly, they examine the benefits (when using a high brightness source) of an extrinsic germanium photoconductive detector with cone optics as a replacement for the standard MCT detector.

  9. Absorbed dose to water: Standards and traceability for radiation oncology

    SciTech Connect

    Almond, P.R.

    1995-12-31

    Although the need for appropriate quantities and units for ionizing radiation has existed since shortly after discovery of X-rays, the quantities and units in general use today were not completely formalized until about 15 years ago. The development of appropriate national and international standards have also been ongoing. For many years the quantity, exposure, measured in units of roentgen was the national standard and they were also the quantity and units in which radiotherapy was described. With the introduction of megavoltage X-ray and electron-beam equipment and the adoption of the quantity {open_quotes}absorbed-dose{close_quotes} measured in units of rad (or gray) different approaches to calibrating these beams were needed. This was especially the case since the national standard in terms of exposure at a maximum photon energy for {sup 60}Co gamma rays was only available. Since the late 1960s various machine calibration protocols have been published. These protocols have to accommodate changes in modality, energy, quantities and units between the national standard and the user. Because of this, a new definition of traceability is proposed to accommodate the present system. By recording all intercomparisons and parameters used, an auditable calibration chain can be maintained. Even with the introduction of calibration protocols based upon national absorbed dose standards, the proposed traceability definition will still be needed.

  10. Radiative transfer effects on reflected shock waves. II - Absorbing gas.

    NASA Technical Reports Server (NTRS)

    Su, F. Y.; Olfe, D. B.

    1972-01-01

    Radiative cooling effects behind a reflected shock wave are calculated for an absorbing-emitting gas by means of an expansion procedure in the small density ratio across the shock front. For a gray gas shock layer with an optical thickness of order unity or less the absorption integral is simplified by use of the local temperature approximation, whereas for larger optical thicknesses a Rosseland diffusion type of solution is matched with the local temperature approximation solution. The calculations show that the shock wave will attenuate at first and then accelerate to a constant velocity. Under appropriate conditions the gas enthalpy near the wall may increase at intermediate times before ultimately decreasing to zero. A two-band absorption model yields end-wall radiant-heat fluxes which agree well with available shock-tube measurements.

  11. Radiation-induced biomarkers for the detection and assessment of absorbed radiation doses

    PubMed Central

    Rana, Sudha; Kumar, Raj; Sultana, Sarwat; Sharma, Rakesh Kumar

    2010-01-01

    Radiation incident involving living organisms is an uncommon but a very serious situation. The first step in medical management including triage is high-throughput assessment of the radiation dose received. Radiation exposure levels can be assessed from viability of cells, cellular organelles such as chromosome and different intermediate metabolites. Oxidative damages by ionizing radiation result in carcinogenesis, lowering of the immune response and, ultimately, damage to the hematopoietic system, gastrointestinal system and central nervous system. Biodosimetry is based on the measurement of the radiation-induced changes, which can correlate them with the absorbed dose. Radiation biomarkers such as chromosome aberration are most widely used. Serum enzymes such as serum amylase and diamine oxidase are the most promising biodosimeters. The level of gene expression and protein are also good biomarkers of radiation. PMID:21829314

  12. Infrared radiation models for atmospheric methane

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Kratz, D. P.; Caldwell, J.; Kim, S. J.

    1986-01-01

    Mutually consistent line-by-line, narrow-band and broad-band infrared radiation models are presented for methane, a potentially important anthropogenic trace gas within the atmosphere. Comparisons of the modeled band absorptances with existing laboratory data produce the best agreement when, within the band models, spurious band intensities are used which are consistent with the respective laboratory data sets, but which are not consistent with current knowledge concerning the intensity of the infrared fundamental band of methane. This emphasizes the need for improved laboratory band absorptance measurements. Since, when applied to atmospheric radiation calculations, the line-by-line model does not require the use of scaling approximations, the mutual consistency of the band models provides a means of appraising the accuracy of scaling procedures. It is shown that Curtis-Godson narrow-band and Chan-Tien broad-band scaling provide accurate means of accounting for atmospheric temperature and pressure variations.

  13. Nanostructured thin film-based near-infrared tunable perfect absorber using phase-change material

    NASA Astrophysics Data System (ADS)

    Kocer, Hasan

    2015-01-01

    Nanostructured thin film absorbers embedded with phase-change thermochromic material can provide a large level of absorption tunability in the near-infrared region. Vanadium dioxide was employed as the phase-change material in the designed structures. The optical absorption properties of the designed structures with respect to the geometric and material parameters were systematically investigated using finite-difference time-domain computations. Absorption level of the resonance wavelength in the near-IR region was tuned from the perfect absorption level to a low level (17%) with a high positive dynamic range of near-infrared absorption intensity tunability (83%). Due to the phase transition of vanadium dioxide, the resonance at the near-infrared region is being turned on and turned off actively and reversibly under the thermal bias, thereby rendering these nanostructures suitable for infrared camouflage, emitters, and sensors.

  14. Development of an infrared radiative heating model

    NASA Technical Reports Server (NTRS)

    Bergstrom, R. W.; Helmle, L. C.

    1979-01-01

    Infrared radiative transfer solution algorithms used in global circulation models were assessed. Computation techniques applicable to the Ames circulation model are identified. Transmission properties of gaseous CO2, H2O, and O3 are gathered, and a computer program is developed, using the line parameter tape and Voight profile subroutine, which computes the transmission of CO2, H2O, and O3. A computer code designed to compute atmospheric cooling rates was developed.

  15. Imaging spectroscopy of albedo and radiative forcing by light-absorbing impurities in mountain snow

    NASA Astrophysics Data System (ADS)

    Painter, Thomas H.; Seidel, Felix C.; Bryant, Ann C.; McKenzie Skiles, S.; Rittger, Karl

    2013-09-01

    Recent studies show that deposition of dust and black carbon to snow and ice accelerates snowmelt and perturbs regional climate and hydrologic cycles. Radiative forcing by aerosols is often neglected in climate and hydrological models in part due to scarcity of observations. Here we describe and validate an algorithm suite (Imaging Spectrometer-Snow Albedo and Radiative Forcing (IS-SnARF)) that provides quantitative retrievals of snow grain size, snow albedo, and radiative forcing by light-absorbing impurities in snow and ice (LAISI) from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data collected on 15 June 2011 in the Senator Beck Basin Study Area (SBBSA), SW Colorado, USA. Radiative forcing by LAISI is retrieved by the integral of the convolution of spectral irradiance with spectral differences between the spectral albedo (scaled from the observed hemispherical-directional reflectance factor (HDRF)) and modeled clean snow spectral albedo. The modeled surface irradiance at time of acquisition at test sites was 1052 W m-2 compared to 1048 W m-2 measured with the field spectroradiometer measurements, a relative difference of 0.4%. HDRF retrievals at snow and bare soil sites had mean errors relative to in situ measurements of -0.4 ± 0.1% reflectance averaged across the spectrum and root-mean-square errors of 1.5 ± 0.1%. Comparisons of snow albedo and radiative forcing retrievals from AVIRIS with in situ measurements in SBBSA showed errors of 0.001-0.004 and 2.1 ± 5.1 W m-2, respectively. A counterintuitive result was that, in the presence of light absorbing impurities, near-surface snow grain size increased with elevation, whereas we generally expect that at lower elevation the grain size would be larger.

  16. Thermal tuning of infrared resonant absorbers based on hybrid gold-VO{sub 2} nanostructures

    SciTech Connect

    Kocer, Hasan; Butun, Serkan; Aydin, Koray; Banar, Berker; Wang, Kevin; Wu, Junqiao; Tongay, Sefaatttin

    2015-04-20

    Resonant absorbers based on plasmonic materials, metamaterials, and thin films enable spectrally selective absorption filters, where absorption is maximized at the resonance wavelength. By controlling the geometrical parameters of nano/microstructures and materials' refractive indices, resonant absorbers are designed to operate at wide range of wavelengths for applications including absorption filters, thermal emitters, thermophotovoltaic devices, and sensors. However, once resonant absorbers are fabricated, it is rather challenging to control and tune the spectral absorption response. Here, we propose and demonstrate thermally tunable infrared resonant absorbers using hybrid gold-vanadium dioxide (VO{sub 2}) nanostructure arrays. Absorption intensity is tuned from 90% to 20% and 96% to 32% using hybrid gold-VO{sub 2} nanowire and nanodisc arrays, respectively, by heating up the absorbers above the phase transition temperature of VO{sub 2} (68 °C). Phase change materials such as VO{sub 2} deliver useful means of altering optical properties as a function of temperature. Absorbers with tunable spectral response can find applications in sensor and detector applications, in which external stimulus such as heat, electrical signal, or light results in a change in the absorption spectrum and intensity.

  17. High-throughput realization of an infrared selective absorber/emitter by DUV microsphere projection lithography.

    PubMed

    Bonakdar, Alireza; Rezaei, Mohsen; Dexheimer, Eric; Mohseni, Hooman

    2016-01-22

    In this paper, we present a low-cost and high-throughput nanofabrication method to realize metasurfaces that have selective absorption/emission in the mid-infrared region of the electromagnetic spectrum. We have developed DUV projection lithography to produce arbitrary patterns with sub-80 nm feature sizes. As examples of practical applications, we experimentally demonstrate structures with single and double spectral absorption/emission features, and in close agreement with numerical simulation. The fundamental mechanism of perfect absorption is discussed as well. Selective infrared absorbers/emitters are critical elements in realizing efficient thermophotovoltaic cells and high-performance biosensors. PMID:26650855

  18. Benzodipyrrole-based Donor-Acceptor-type Boron Complexes as Tunable Near-infrared-Absorbing Materials.

    PubMed

    Nakamura, Tomoya; Furukawa, Shunsuke; Nakamura, Eiichi

    2016-07-20

    Benzodipyrrole-based donor-acceptor boron complexes were designed and synthesized as near-infrared-absorbing materials. The electron-rich organic framework combined with the Lewis acidic boron co-ordination enabled us to tune the LUMO energy level and the HOMO-LUMO gap (i.e.,the absorption wavelength) by changing the organic acceptor units, the number of boron atoms, and the substituents on the boron atoms.

  19. Dual-band absorber for multispectral plasmon-enhanced infrared photodetection

    NASA Astrophysics Data System (ADS)

    Yu, Peng; Wu, Jiang; Ashalley, Eric; Govorov, Alexander; Wang, Zhiming

    2016-09-01

    For most of the reported metamaterial absorbers, the peak absorption only occurs at one single wavelength. Here, we investigated a dual-band absorber which is based on simple gold nano-rings. Two absorption peaks can be readily achieved in 3-5 µm and 8-14 µm via tuning the width and radius of gold nano-rings and dielectric constant. The average maximum absorption of two bands can be as high as 95.1% (-0.22 dB). Based on the simulation results, the perfect absorber with nano-rings demonstrates great flexibility to create dual-band or triple-band absorption, and thus holds potential for further applications in thermophotovoltaics, multicolor infrared focal plane arrays, optical filters, and biological sensing applications.

  20. Dual-band absorber for multispectral plasmon-enhanced infrared photodetection

    NASA Astrophysics Data System (ADS)

    Yu, Peng; Wu, Jiang; Ashalley, Eric; Govorov, Alexander; Wang, Zhiming

    2016-09-01

    For most of the reported metamaterial absorbers, the peak absorption only occurs at one single wavelength. Here, we investigated a dual-band absorber which is based on simple gold nano-rings. Two absorption peaks can be readily achieved in 3–5 µm and 8–14 µm via tuning the width and radius of gold nano-rings and dielectric constant. The average maximum absorption of two bands can be as high as 95.1% (‑0.22 dB). Based on the simulation results, the perfect absorber with nano-rings demonstrates great flexibility to create dual-band or triple-band absorption, and thus holds potential for further applications in thermophotovoltaics, multicolor infrared focal plane arrays, optical filters, and biological sensing applications.

  1. Angular absorbed dose dependence of internal radiation-generating devices in radiotherapy.

    PubMed

    Bevelacqua, J J

    2012-01-01

    The angular dependence of the absorbed dose from internal radiation-generating devices located within a tumor mass is investigated. Given the systematics of proton and heavy-ion differential scattering cross sections, candidate internal radiation-generating devices will have a relatively constant absorbed dose output beyond a critical angle. Inside this angle, the absorbed dose output is suppressed because elastic and inelastic differential cross sections are peaked in the beam direction. This peaking increases in severity as the particle energy increases and suggests internal radiation-generating devices must have a limited rotation capability to compensate for the depression in the absorbed dose for angles near the beam direction.

  2. The Visualization of Infrared Radiation Using Thermal Sensitive Foils

    ERIC Educational Resources Information Center

    Bochnícek, Zdenek

    2013-01-01

    This paper describes a set of demonstration school experiments where infrared radiation is detected using thermal sensitive foils. The possibility of using standard glass lenses for infrared imaging is discussed in detail. It is shown that with optic components made from glass, infrared radiation up to 2.5 µm of wavelength can be detected. The…

  3. Enhanced spatial near-infrared modulation of graphene-loaded perfect absorbers using plasmonic nanoslits.

    PubMed

    Cai, Yijun; Zhu, Jinfeng; Liu, Qing Huo; Lin, Timothy; Zhou, Jianyang; Ye, Longfang; Cai, Zhiping

    2015-12-14

    Modulating spatial near-infrared light for ultra-compact electro-optic devices is a critical issue in optical communication and imaging applications. To date, spatial near-infrared modulators based on graphene have been reported, but they showed limited modulation effects due to the relatively weak light-graphene interaction. In combination with graphene and metallic nanoslits, we design a kind of ultrathin near-infrared perfect absorber with enhanced spatial modulation effects and independence on a wide range of incident angles. The modulated spectral shift of central wavelength is up to 258.2 nm in the near-infrared range, which is more promising in applications than state-of-the-art devices. The modulation enhancement is attributed to the plasmonic nanoslit mode, in which the optical electric field is highly concentrated in the deep subwavelength scale and the light-graphene interaction is significantly strengthened. The physical insight is deeply revealed by a combination of equivalent circuit and electromagnetic field analysis. The design principles are not only crucial for spatial near-infrared modulators, but also provide a key guide for developing active near-infrared patch nanoantennas based on graphene.

  4. Method for generation of tunable far infrared radiation from two-dimensional plasmons

    NASA Technical Reports Server (NTRS)

    Katz, Joseph (Inventor)

    1989-01-01

    Tunable far infrared radiation is produced from two-dimensional plasmons in a heterostructure, which provides large inversion-layer electron densities at the heterointerface, without the need for a metallic grating to couple out the radiation. Instead, a light interference pattern is produced on the planar surface of the heterostructure using two coherent laser beams of a wavelength selected to be strongly absorbed by the heterostructure in order to penetrate through the inversion layer. The wavelength of the far infrared radiation coupled out can then be readily tuned by varying the angle between the coherent beams, or varying the wavelength of the two interfering coherent beams, thus varying the periodicity of the photoconductivity grating to vary the wavelength of the far infrared radiation being coupled out.

  5. Design and simulation of multi-color infrared CMOS metamaterial absorbers

    NASA Astrophysics Data System (ADS)

    Cheng, Zhengxi; Chen, Yongping; Ma, Bin

    2016-05-01

    Metamaterial electromagnetic wave absorbers, which usually can be fabricated in a low weight thin film structure, have a near unity absorptivity in a special waveband, and therefore have been widely applied from microwave to optical waveband. To increase absorptance of CMOS MEMS devices in 2-5 μmm waveband, multi-color infrared metamaterial absorbers are designed with CSMC 0.5 μmm 2P3M and 0.18 μmm 1P6M CMOS technology in this work. Metal-insulator-metal (MIM) three-layer MMAs and Insulator-metal-insulator-metal (MIMI) four-layer MMAs are formed by CMOS metal interconnect layers and inter metal dielectrics layer. To broaden absorption waveband in 2-5μmm range, MMAs with a combination of different sizes cross bars are designed. The top metal layer is a periodic aluminum square array or cross bar array with width ranging from submicron to several microns. The absorption peak position and intensity of MMAs can be tuned by adjusting the top aluminum micro structure array. Post-CMOS process is adopted to fabricate MMAs. The infrared absorption spectra of MMAs are verified with finite element method simulation, and the effects of top metal structure sizes, patterns, and films thickness are also simulated and intensively discussed. The simulation results show that CMOS MEMS MMAs enhance infrared absorption in 2-20 μmm. The MIM broad MMA has an average absorptance of 0.22 in 2-5 μmm waveband, and 0.76 in 8-14 μm waveband. The CMOS metamaterial absorbers can be inherently integrated in many kinds of MEMS devices fabricated with CMOS technology, such as uncooled bolometers, infrared thermal emitters.

  6. [The study of transpiration influence on plant infrared radiation character].

    PubMed

    Ling, Jun; Zhang, Shuan-Qin; Pan, Jia-Liang; Lian, Chang-Chun; Yang, Hui

    2012-07-01

    Studying vegetation infrared radiation character is the base of developing infrared camouflage and concealment technology of ground military target. Accurate fusion of target and background can be achieved by simulating formation mechanism of vegetation infrared radiation character. Leaf transpiration is characteristic physiological mechanism of vegetation and one of the main factors that influence its infrared radiation character. In the present paper, physical model of leaf energy balance is set up. Based on this model the influence of plant transpiration on leaf temperature is analyzed and calculated. The daily periodic variation of transpiration, leaf temperature and infrared radiation character of typical plants such as camphor tree and holly is actually measured with porometer and infrared thermal imaging system. By contrasting plant leaf with dryness leaf, experimental data indicates that plant transpiration can regulate leaf energy balance effectively and control leaf temperature in a reasonable range and suppress deep range variation of leaf infrared radiation character.

  7. Infrared radiation models for atmospheric ozone

    NASA Technical Reports Server (NTRS)

    Kratz, David P.; Ces, Robert D.

    1988-01-01

    A hierarchy of line-by-line, narrow-band, and broadband infrared radiation models are discussed for ozone, a radiatively important atmospheric trace gas. It is shown that the narrow-band (Malkmus) model is in near-precise agreement with the line-by-line model, thus providing a means of testing narrow-band Curtis-Godson scaling, and it is found that this scaling procedure leads to errors in atmospheric fluxes of up to 10 percent. Moreover, this is a direct consequence of the altitude dependence of the ozone mixing ratio. Somewhat greater flux errors arise with use of the broadband model, due to both a lesser accuracy of the broadband scaling procedure and to inherent errors within the broadband model, despite the fact that this model has been tuned to the line-by-line model.

  8. Infrared-transparent gold nanoparticles converted by tumors to infrared absorbers cure tumors in mice by photothermal therapy.

    PubMed

    Hainfeld, James F; O'Connor, Michael J; Lin, Ping; Qian, Luping; Slatkin, Daniel N; Smilowitz, Henry M

    2014-01-01

    Gold nanoparticles (AuNPs) absorb light and can be used to heat and ablate tumors. The "tissue window" at ∼ 800 nm (near infrared, NIR) is optimal for best tissue penetration of light. Previously, large, 50-150 nm, gold nanoshells and nanorods that absorb well in the NIR have been used. Small AuNPs that may penetrate tumors better unfortunately barely absorb at 800 nm. We show that small AuNPs conjugated to anti-tumor antibodies are taken up by tumor cells that catalytically aggregate them (by enzyme degradation of antibodies and pH effects), shifting their absorption into the NIR region, thus amplifying their photonic absorption. The AuNPs are NIR transparent until they accumulate in tumor cells, thus reducing background heating in blood and non-targeted cells, increasing specificity, in contrast to constructs that are always NIR-absorptive. Treatment of human squamous cell carcinoma A431 which overexpresses epidermal growth factor receptor (EGFr) in subcutaneous murine xenografts with anti-EGFr antibodies conjugated to 15 nm AuNPs and NIR resulted in complete tumor ablation in most cases with virtually no normal tissue damage. The use of targeted small AuNPs therefore provides a potent new method of selective NIR tumor therapy.

  9. Radiation response issues for infrared detectors

    NASA Technical Reports Server (NTRS)

    Kalma, Arne H.

    1990-01-01

    Researchers describe the most important radiation response issues for infrared detectors. In general, the two key degradation mechanisms in infrared detectors are the noise produced by exposure to a flux of ionizing particles (e.g.; trapped electronics and protons, debris gammas and electrons, radioactive decay of neutron-activated materials) and permanent damage produced by exposure to total dose. Total-dose-induced damage is most often the result of charge trapping in insulators or at interfaces. Exposure to short pulses of ionization (e.g.; prompt x rays or gammas, delayed gammas) will cause detector upset. However, this upset is not important to a sensor unless the recovery time is too long. A few detector technologies are vulnerable to neutron-induced displacement damage, but fortunately most are not. Researchers compare the responses of the new technologies with those of the mainstream technologies of PV HgCdTe and IBC Si:As. One important reason for this comparison is to note where some of the newer technologies have the potential to provide significantly improved radiation hardness compared with that of the mainstream technologies, and thus to provide greater motivation for the pursuit of these technologies.

  10. Infrared Signature Masking by Air Plasma Radiation

    NASA Technical Reports Server (NTRS)

    Kruger, Charles H.; Laux, C. O.

    2001-01-01

    This report summarizes the results obtained during a research program on the infrared radiation of air plasmas conducted in the High Temperature Gasdynamics Laboratory at Stanford University under the direction of Professor Charles H. Kruger, with Dr. Christophe O. Laux as Associate Investigator. The goal of this research was to investigate the masking of infrared signatures by the air plasma formed behind the bow shock of high velocity missiles. To this end, spectral measurements and modeling were made of the radiation emitted between 2.4 and 5.5 micrometers by an atmospheric pressure air plasma in chemical and thermal equilibrium at a temperature of approximately 3000 K. The objective was to examine the spectral emission of air species including nitric oxide, atomic oxygen and nitrogen lines, molecular and atomic continua, as well as secondary species such as water vapor or carbon dioxide. The cold air stream injected in the plasma torch contained approximately 330 parts per million of CO2, which is the natural CO2 concentration in atmospheric air at room temperatures, and a small amount of water vapor with an estimated mole fraction of 3.8x10(exp -4).

  11. Black silicon-based infrared radiation source

    NASA Astrophysics Data System (ADS)

    Anwar, Momen; Sabry, Yasser; Basset, Philippe; Marty, Frédéric; Bourouina, Tarik; Khalil, Diaa

    2016-03-01

    Micromachined infrared sources are enabling component for interferometric and spectroscopic sensors. Their compact size and low cost transform bulky instruments to the sensor scale, which is needed for a wide range of applications in the conventional and unconventional environments. The silicon micromachined sources should be engineered to have good emissivity across a large wavelength range because the intrinsic emissivity of silicon is low. This optimization was reported in literature by either the deposition of black metal at the surface of an emitter or the use of deep phonic crystal cavities, which complicates the fabrication technology and results in sharp dip lines in the spectral emissivity, respectively. In this work we report a micromachined infrared radiation source based on a heater on the top of black silicon structure for the first time in the literature, up to the authors' knowledge. The temperature of the device is characterized versus the applied voltage and the radiated spectrum is captured in the 1300 nm to 2500 nm spectral range; limited by the spectrum analysis instrument. The reported source opens the doors for completely integrated MEMS spectral sensors onchip.

  12. Infrared Signature Masking by Air Plasma Radiation

    NASA Technical Reports Server (NTRS)

    Kruger, C. H.; Laux, C. O.

    1998-01-01

    This report describes progress during the second year of our research program on Infrared Signature Masking by Air Plasmas at Stanford University. This program is intended to investigate the masking of infrared signatures by the air plasma formed behind the bow shock of high velocity missiles. Our previous annual report described spectral measurements and modeling of the radiation emitted between 3.2 and 5.5 microns by an atmospheric pressure air plasma in chemical and thermal equilibrium at a temperature of approximately 3100 K. One of our goals was to examine the spectral emission of secondary species such as water vapor or carbon dioxide. The cold air stream injected in the plasma torch contained approximately 330 parts per million Of CO2, which is the natural CO2 concentration in atmospheric air at room temperature, and a small amount of water vapor with an estimated mole fraction of 3.8 x 10(exp -4). As can be seen from Figure 1, it was found that the measured spectrum exhibited intense spectral features due to the fundamental rovibrational bands of NO at 4.9 - 5.5 microns and the V(3) band of CO2 (antisymmetric stretch) at 4.2-4.8 microns. These observations confirmed the well-known fact that infrared signatures between 4.15 - 5.5 microns can be masked by radiative emission in the interceptor's bow-shock. Figure I also suggested that the range 3.2 - 4.15 microns did not contain any significant emission features (lines or continuum) that could mask IR signatures. However, the signal-to-noise level, close to one in that range, precluded definite conclusions. Thus, in an effort to further investigate the spectral emission in the range of interest to signature masking problem, new measurements were made with a higher signal-to-noise ratio and an extended wavelength range.

  13. Symmetric Absorber-Coupled Far-Infrared Microwave Kinetic Inductance Detector

    NASA Technical Reports Server (NTRS)

    U-yen, Kongpop (Inventor); Wollack, Edward J. (Inventor); Brown, Ari D. (Inventor); Stevenson, Thomas R. (Inventor); Patel, Amil A. (Inventor)

    2016-01-01

    The present invention relates to a symmetric absorber-coupled far-infrared microwave kinetic inductance detector including: a membrane having an absorber disposed thereon in a symmetric cross bar pattern; and a microstrip including a plurality of conductor microstrip lines disposed along all edges of the membrane, and separated from a ground plane by the membrane. The conducting microstrip lines are made from niobium, and the pattern is made from a superconducting material with a transition temperature below niobium, including one of aluminum, titanium nitride, or molybdenum nitride. The pattern is disposed on both a top and a bottom of the membrane, and creates a parallel-plate coupled transmission line on the membrane that acts as a half-wavelength resonator at readout frequencies. The parallel-plate coupled transmission line and the conductor microstrip lines form a stepped impedance resonator. The pattern provides identical power absorption for both horizontal and vertical polarization signals.

  14. Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered thin films

    PubMed Central

    Kocer, Hasan; Butun, Serkan; Palacios, Edgar; Liu, Zizhuo; Tongay, Sefaattin; Fu, Deyi; Wang, Kevin; Wu, Junqiao; Aydin, Koray

    2015-01-01

    Plasmonic and metamaterial based nano/micro-structured materials enable spectrally selective resonant absorption, where the resonant bandwidth and absorption intensity can be engineered by controlling the size and geometry of nanostructures. Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition. Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20 nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum. Our numerical and experimental results indicate that the bandwidth of the absorption bands can be controlled by changing the dielectric spacer layer thickness. Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing. PMID:26294085

  15. Electrically tunable metasurface perfect absorbers for ultrathin mid-infrared optical modulators.

    PubMed

    Yao, Yu; Shankar, Raji; Kats, Mikhail A; Song, Yi; Kong, Jing; Loncar, Marko; Capasso, Federico

    2014-11-12

    Dynamically reconfigurable metasurfaces open up unprecedented opportunities in applications such as high capacity communications, dynamic beam shaping, hyperspectral imaging, and adaptive optics. The realization of high performance metasurface-based devices remains a great challenge due to very limited tuning ranges and modulation depths. Here we show that a widely tunable metasurface composed of optical antennas on graphene can be incorporated into a subwavelength-thick optical cavity to create an electrically tunable perfect absorber. By switching the absorber in and out of the critical coupling condition via the gate voltage applied on graphene, a modulation depth of up to 100% can be achieved. In particular, we demonstrated ultrathin (thickness < λ0/10) high speed (up to 20 GHz) optical modulators over a broad wavelength range (5-7 μm). The operating wavelength can be scaled from the near-infrared to the terahertz by simply tailoring the metasurface and cavity dimensions. PMID:25310847

  16. 10.4% Efficient triple organic solar cells containing near infrared absorbers

    NASA Astrophysics Data System (ADS)

    Meerheim, Rico; Körner, Christian; Oesen, Benjamin; Leo, Karl

    2016-03-01

    The efficiency of organic solar cells can be increased by serially stacked subcells with spectrally different absorber materials. For the triple junction devices presented here, we use the small molecule donor materials DCV5T-Me for the green region and Tol2-benz-bodipy or Ph2-benz-bodipy as near infrared absorbers. The broader spectral response allows an efficiency increase from a pure DCV5T-Me triple cell to a triple junction containing a Ph2-benz-bodipy subcell, reaching 10.4%. As often observed for organic photovoltaics, the efficiency is further increased at low light intensities to 11%, which allows improved energy harvesting under real outdoor conditions and better performance indoor.

  17. Near-Infrared Imaging of Six Metal-rich Quasar Absorber Galaxy Fields

    NASA Astrophysics Data System (ADS)

    Straka, Lorrie A.; Kulkarni, Varsha P.; York, Donald G.

    2011-06-01

    Absorption lines in quasar spectra allow us to locate and study intervening galaxies. In order to obtain a clearer picture of these absorber galaxies, we have used the Near-Infrared Camera Fabry-Perot System at Apache Point Observatory to obtain near-infrared broadband images in one or more filters (J and Ks ) of six quasar fields containing metal-rich low-z damped or sub-damped Lyα systems. These data allow us to search for the galaxies and constrain their luminosities. Candidate absorber galaxies are detected at 2farcs01-7farcs38 separation from the quasar in three out of six fields in the J and Ks bands at >3σ level with luminosities ranging from log(L/L sun) = 10.44-10.36 in the J band (for E-Sc type galaxies) and log(L/L sun) = 11.59-10.03 in the Ks band for our detections. We place limits on the remaining fields with no detections of log(L/L sun) <10.83-9.75 for the J band and log(L/L sun) <10.43-10.05 for the Ks band. We are also able to utilize Sloan Digital Sky Survey spectra for each field to calculate optical fluxes and limits as well as limits on star formation rate via [O II]λ3727 emission in spectra. Our data, combined with other recent imaging results for metal-rich absorbers, suggest a possible positive correlation between absorber metallicity and galaxy luminosity, although the samples are still small.

  18. NEAR-INFRARED IMAGING OF SIX METAL-RICH QUASAR ABSORBER GALAXY FIELDS

    SciTech Connect

    Straka, Lorrie A.; Kulkarni, Varsha P.; York, Donald G.

    2011-06-15

    Absorption lines in quasar spectra allow us to locate and study intervening galaxies. In order to obtain a clearer picture of these absorber galaxies, we have used the Near-Infrared Camera Fabry-Perot System at Apache Point Observatory to obtain near-infrared broadband images in one or more filters (J and K{sub s} ) of six quasar fields containing metal-rich low-z damped or sub-damped Ly{alpha} systems. These data allow us to search for the galaxies and constrain their luminosities. Candidate absorber galaxies are detected at 2.''01-7.''38 separation from the quasar in three out of six fields in the J and K{sub s} bands at >3{sigma} level with luminosities ranging from log(L/L{sub sun}) = 10.44-10.36 in the J band (for E-Sc type galaxies) and log(L/L{sub sun}) = 11.59-10.03 in the K{sub s} band for our detections. We place limits on the remaining fields with no detections of log(L/L{sub sun}) <10.83-9.75 for the J band and log(L/L{sub sun}) <10.43-10.05 for the K{sub s} band. We are also able to utilize Sloan Digital Sky Survey spectra for each field to calculate optical fluxes and limits as well as limits on star formation rate via [O II]{lambda}3727 emission in spectra. Our data, combined with other recent imaging results for metal-rich absorbers, suggest a possible positive correlation between absorber metallicity and galaxy luminosity, although the samples are still small.

  19. Far-infrared self-broadening in methylcyanide - Absorber-perturber resonance

    NASA Technical Reports Server (NTRS)

    Buffa, G.; Tarrini, O.; De Natale, P.; Inguscio, M.; Pavone, F. S.; Prevedelli, M.; Evenson, K. M.; Zink, L. R.; Schwaab, G. W.

    1992-01-01

    Using tunable far-infrared spectrometers with high-frequency stability and accuracy, the self-pressure broadening and shift of CH3CN are measured. Evidence of absorber-perturber resonance effects on the collisional line shape are obtained. This tests the theoretical model and its possible improvements and also allows predictions of broadening and shift for a large class of molecules. Moreover, the resonance effect produces a theoretical temperature dependence of self-broadening that is different from what is commonly assumed.

  20. Mid-wave interband cascade infrared photodetectors based on GaInAsSb absorbers

    NASA Astrophysics Data System (ADS)

    Lei, Lin; Li, Lu; Lotfi, Hossein; Jiang, Yuchao; Yang, Rui Q.; Johnson, Matthew B.; Lubyshev, Dmitri; Qiu, Yueming; Fastenau, Joel M.; Liu, Amy W. K.

    2016-10-01

    In this work, we report the demonstration of quaternary GaInAsSb-based mid-wavelength infrared photodetectors with cutoff wavelengths longer than 4 μm at 300 K. Both interband cascade infrared photodetector (ICIP) with a three-stage discrete absorber architecture and conventional one-stage detector structures have been grown by molecular beam epitaxy and investigated in experiments for their electrical and optical properties. High absorption coefficient and gain were observed in both detector structures. The three-stage ICIPs had superior carrier transport over the one-stage detectors. A detectivity as high as 1.0 × 109 cm Hz1/2 W-1 was achieved at 3.3 μm for both one- and three-stage detectors under zero bias at 300 K. The implications of these results are discussed along with potential of GaInAsSb-based ICIPs for high-speed applications.

  1. Biological applications of synchrotron radiation infrared spectromicroscopy.

    PubMed

    Marcelli, Augusto; Cricenti, Antonio; Kwiatek, Wojciech M; Petibois, Cyril

    2012-01-01

    Extremely brilliant infrared (IR) beams provided by synchrotron radiation sources are now routinely used in many facilities with available commercial spectrometers coupled to IR microscopes. Using these intense non-thermal sources, a brilliance two or three order of magnitude higher than a conventional source is achievable through small pinholes (<10 μm) with a high signal to-noise ratio. IR spectroscopy is a powerful technique to investigate biological systems and offers many new imaging opportunities. The field of infrared biological imaging covers a wide range of fundamental issues and applied researches such as cell imaging or tissue imaging. Molecular maps with a spatial resolution down to the diffraction limit may be now obtained with a synchrotron radiation IR source also on thick samples. Moreover, changes of the protein structure are detectable in an IR spectrum and cellular molecular markers can be identified and used to recognize a pathological status of a tissue. Molecular structure and functions are strongly correlated and this aspect is particularly relevant for imaging. We will show that the brilliance of synchrotron radiation IR sources may enhance the sensitivity of a molecular signal obtained from small biosamples, e.g., a single cell, containing extremely small amounts of organic matter. We will also show that SR IR sources allow to study chemical composition and to identify the distribution of organic molecules in cells at submicron resolution is possible with a high signal-to-noise ratio. Moreover, the recent availability of two-dimensional IR detectors promises to push forward imaging capabilities in the time domain. Indeed, with a high current synchrotron radiation facility and a Focal Plane Array the chemical imaging of individual cells can be obtained in a few minutes. Within this framework important results are expected in the next years using synchrotron radiation and Free Electron Laser (FEL) sources for spectro-microscopy and spectral

  2. Infrared band absorptance correlations and applications to nongray radiation. [mathematical models of absorption spectra for nongray atmospheres in order to study air pollution

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Manian, S. V. S.

    1976-01-01

    Various mathematical models for infrared radiation absorption spectra for atmospheric gases are reviewed, and continuous correlations for the total absorptance of a wide band are presented. Different band absorptance correlations were employed in two physically realistic problems (radiative transfer in gases with internal heat source, and heat transfer in laminar flow of absorbing-emitting gases between parallel plates) to study their influence on final radiative transfer results. This information will be applied to the study of atmospheric pollutants by infrared radiation measurement.

  3. Thermal Infrared Radiative Forcing By Atmospheric Aerosol

    NASA Astrophysics Data System (ADS)

    Adhikari, Narayan

    The work mainly focuses on the study of thermal infrared (IR) properties of atmospheric greenhouse gases and aerosols, and the estimation of the aerosol-induced direct longwave (LW) radiative forcing in the spectral region 5-20 mum at the Earth's surface (BOA; bottom of the atmosphere) and the top of the atmosphere (TOA) in cloud-free atmospheric conditions. These objectives were accomplished by conducting case studies on clear sky, smoky, and dusty conditions that took place in the Great Basin of the USA in 2013. Both the solar and thermal IR measurements and a state-of-the-science radiative transfer model, the LBLDIS, a combination of the Line-By-Line Radiative Transfer Model and the Discrete Ordinate Radiative Transfer (DISORT) solver were employed for the study. The LW aerosol forcing is often not included in climate models because the aerosol effect on the LW is often assumed to be negligible. We lack knowledge of aerosol characteristics in the LW region, and aerosol properties exhibit high variability. We have found that the LW TOA radiative forcing due to fine mode aerosols, mainly associated with small biomass burning smoke particles, is + 0.4 W/m2 which seems to be small, but it is similar to the LW radiative forcing due to increase in CO2 concentration in the Earth's atmosphere since the preindustrial era of 1750 (+ 1.6 W/m 2). The LW radiative forcing due to coarse mode aerosols, associated with large airborne mineral dust particles, was found to be as much as + 5.02 W/m2 at the surface and + 1.71 W/m2 at the TOA. All of these significant positive values of the aerosol radiative forcing both at the BOA and TOA indicate that the aerosols have a heating effect in the LW range, which contributes to counterbalancing the cooling effect associated with the aerosol radiative forcing in the shortwave (SW) spectral region. In the meantime, we have found that LW radiative forcing by aerosols is highly sensitive to particle size and complex refractive indices of

  4. Near-infrared absorbance measurements of hemoglobin solutions incubated with glucose

    NASA Astrophysics Data System (ADS)

    Zhernovaya, Olga S.; Tuchin, Valery V.; Meglinski, Igor; Ritchie, Laurie

    2007-02-01

    It is known that glucose influences on spectral properties of blood and hemoglobin and interacts with plasma proteins and hemoglobin in erythrocytes. Changes of optical properties of blood and hemoglobin at glucose concentration within physiological level are important for diagnosis and monitoring of diabetes. The purpose of this study is to investigate the effect of presence of glucose and glycation of hemoglobin on absorbance of aqueous hemoglobin solutions with different glucose concentrations. Measurements were taken using spectrophotometer EQUINOX 55 (Bruker Optic GmbH) in a range 1000-1800 nm. Water has absorption bands in the near-infrared region which may be influenced by glucose presence. We have hypothesized that glucose and hemoglobin, especially glycated hemoglobin, may influence the absorption band of water in solution. The hemoglobin solutions with different amount of glucose (from 0 to 1000 mg/dl with a step 100 mg/dl) were incubated up to 28 days. Our measurements show that presence of glucose affects the spectra of aqueous hemoglobin solutions. The magnitude of absorbance depends on glucose concentration. At the beginning of incubation hemoglobin solution without glucose has the lowest absorbance magnitude, but after a rather long time of incubation (28 days) the absorbance of hemoglobin solutions with glucose become smaller compared to the absorbance of hemoglobin solution without glucose. This fact may be explained by assumption of hemoglobin glycation, when glucose molecules chemically bind to hemoglobin, and water binding to hemoglobin. In the case of water binding to hemoglobin molecules the amount of free water molecules in solution decreases, so the water aborbance is excepted to decrease.

  5. Infrared Camera System for Visualization of IR-Absorbing Gas Leaks

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Immer, Christopher; Cox, Robert

    2010-01-01

    Leak detection and location remain a common problem in NASA and industry, where gas leaks can create hazardous conditions if not quickly detected and corrected. In order to help rectify this problem, this design equips an infrared (IR) camera with the means to make gas leaks of IR-absorbing gases more visible for leak detection and location. By comparing the output of two IR cameras (or two pictures from the same camera under essentially identical conditions and very closely spaced in time) on a pixel-by-pixel basis, one can cancel out all but the desired variations that correspond to the IR absorption of the gas of interest. This can be simply done by absorbing the IR lines that correspond to the gas of interest from the radiation received by one of the cameras by the intervention of a filter that removes the particular wavelength of interest from the "reference" picture. This can be done most sensitively with a gas filter (filled with the gas of interest) placed in front of the IR detector array, or (less sensitively) by use of a suitable line filter in the same location. This arrangement would then be balanced against the unfiltered "measurement" picture, which will have variations from IR absorption from the gas of interest. By suitable processing of the signals from each pixel in the two IR pictures, the user can display only the differences in the signals. Either a difference or a ratio output of the two signals is feasible. From a gas concentration viewpoint, the ratio could be processed to show the column depth of the gas leak. If a variation in the background IR light intensity is present in the field of view, then large changes in the difference signal will occur for the same gas column concentration between the background and the camera. By ratioing the outputs, the same signal ratio is obtained for both high- and low-background signals, even though the low-signal areas may have greater noise content due to their smaller signal strength. Thus, one

  6. Infrared radiation of thin plastic films.

    NASA Technical Reports Server (NTRS)

    Tien, C. L.; Chan, C. K.; Cunnington, G. R.

    1972-01-01

    A combined analytical and experimental study is presented for infrared radiation characteristics of thin plastic films with and without a metal substrate. On the basis of the thin-film analysis, a simple analytical technique is developed for determining band-averaged optical constants of thin plastic films from spectral normal transmittance data for two different film thicknesses. Specifically, the band-averaged optical constants of polyethylene terephthalate and polyimide were obtained from transmittance measurements of films with thicknesses in the range of 0.25 to 3 mil. The spectral normal reflectance and total normal emittance of the film side of singly aluminized films are calculated by use of optical constants; the results compare favorably with measured values.

  7. Nanoantennas for visible and infrared radiation.

    PubMed

    Biagioni, Paolo; Huang, Jer-Shing; Hecht, Bert

    2012-02-01

    Nanoantennas for visible and infrared radiation can strongly enhance the interaction of light with nanoscale matter by their ability to efficiently link propagating and spatially localized optical fields. This ability unlocks an enormous potential for applications ranging from nanoscale optical microscopy and spectroscopy over solar energy conversion, integrated optical nanocircuitry, opto-electronics and density-of-states engineering to ultra-sensing as well as enhancement of optical nonlinearities. Here we review the current understanding of metallic optical antennas based on the background of both well-developed radiowave antenna engineering and plasmonics. In particular, we discuss the role of plasmonic resonances on the performance of nanoantennas and address the influence of geometrical parameters imposed by nanofabrication. Finally, we give a brief account of the current status of the field and the major established and emerging lines of investigation in this vivid area of research.

  8. Radiative Transfer Simulations of Infrared Dark Clouds

    NASA Astrophysics Data System (ADS)

    Pavlyuchenkov, Yaroslav; Wiebe, Dmitry; Fateeva, Anna; Vasyunina, Tatiana

    2011-04-01

    The determination of prestellar core structure is often based on observations of (sub)millimeter dust continuum. However, recently the Spitzer Space Telescope provided us with IR images of many objects not only in emission but also in absorption. We developed a technique to reconstruct the density and temperature distributions of protostellar objects based on radiation transfer (RT) simulations both in mm and IR wavelengths. Best-fit model parameters are obtained with the genetic algorithm. We apply the method to two cores of Infrared Dark Clouds and show that their observations are better reproduced by a model with an embedded heating source despite the lack of 70 μm emission in one of these cores. Thus, the starless nature of massive cores can only be established with the careful case-by-case RT modeling.

  9. Transport of infrared radiation in cuboidal clouds

    NASA Technical Reports Server (NTRS)

    HARSHVARDHAN; Weinman, J. A.; Davies, R.

    1981-01-01

    The transport of infrared radiation in a single cuboidal cloud using a vertical two steam approximation was modeled. The emittance of the top face of the model cloud is always less than that for a plane parallel cloud of the same optical depth. The hemisphere flux escaping from the cloud top has a gradient from the center to the edges which brighten when the cloud is over warmer ground. Cooling rate calculations in the 8 to 13.6 micrometer region show that there is cooling from the sides of the cloud at all levels even when there is heating of the core from the ground below. The radiances exiting from model cuboidal clouds were computed by path integration over the source function obtained with the two stream approximation. It is suggested that the brightness temperature measured from finite clouds will overestimate the cloud top temperature.

  10. Experimental study of acoustic radiation force of an ultrasound beam on absorbing and scattering objects

    SciTech Connect

    Nikolaeva, Anastasiia V. Kryzhanovsky, Maxim A.; Tsysar, Sergey A.; Kreider, Wayne; Sapozhnikov, Oleg A.

    2015-10-28

    Acoustic radiation force is a nonlinear acoustic effect caused by the transfer of wave momentum to absorbing or scattering objects. This phenomenon is exploited in modern ultrasound metrology for measurement of the acoustic power radiated by a source and is used for both therapeutic and diagnostic sources in medical applications. To calculate radiation force an acoustic hologram can be used in conjunction with analytical expressions based on the angular spectrum of the measured field. The results of an experimental investigation of radiation forces in two different cases are presented in this paper. In one case, the radiation force of an obliquely incident ultrasound beam on a large absorber (which completely absorbs the beam) is considered. The second case concerns measurement of the radiation force on a spherical target that is small compared to the beam diameter.

  11. Experimental study of acoustic radiation force of an ultrasound beam on absorbing and scattering objects

    NASA Astrophysics Data System (ADS)

    Nikolaeva, Anastasiia V.; Kryzhanovsky, Maxim A.; Tsysar, Sergey A.; Kreider, Wayne; Sapozhnikov, Oleg A.

    2015-10-01

    Acoustic radiation force is a nonlinear acoustic effect caused by the transfer of wave momentum to absorbing or scattering objects. This phenomenon is exploited in modern ultrasound metrology for measurement of the acoustic power radiated by a source and is used for both therapeutic and diagnostic sources in medical applications. To calculate radiation force an acoustic hologram can be used in conjunction with analytical expressions based on the angular spectrum of the measured field. The results of an experimental investigation of radiation forces in two different cases are presented in this paper. In one case, the radiation force of an obliquely incident ultrasound beam on a large absorber (which completely absorbs the beam) is considered. The second case concerns measurement of the radiation force on a spherical target that is small compared to the beam diameter.

  12. Infrared non-planar plasmonic perfect absorber for enhanced sensitive refractive index sensing

    NASA Astrophysics Data System (ADS)

    Cheng, Yongzhi; Mao, Xue Song; Wu, Chenjun; Wu, Lin; Gong, RongZhou

    2016-03-01

    We present a non-planar all-metal plasmonic perfect absorber (PA) with response polarization independent in infrared region, which can be served as a sensor for enhanced refractive index sensing. Distinct from previous designs, the proposed PA consisted of all metal structured film constructed with an assembly of four-tined rod resonators (FRRs). The PA with a high quality-factor (Q-factor) of 41.2 and an absorbance of 99.9% at 142.6 THz has been demonstrated numerically. The resonance behavior occurs in the space between the rods of the FRRs, which is remarkable different conventional sandwiched structural PAs. Based on equivalent LC circuit theory, the absorption peak can be finely tuned by varying the geometrical dimensions of the FRRs. Furthermore, the resonance frequency shows highly sensitive response to the change of refractive index in the surrounding medium. A careful design for refractive index sensor can yield a sensitivity of 1445 nm/refractive index unit (RIU) and a figure of merit (FOM) of 28.8. The demonstrated design of the plasmonic PA for sensing provides great potential application in enhancing refractive index sensors and the enhanced infrared spectroscopy.

  13. Infrared radiation budget of the Harmattan haze. [West Africa

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.; Weickmann, H. K.

    1975-01-01

    Infrared in situ observations of the West African Harmaltan Haze during the 1974 GATE field phase were conducted to determine the radiative properties of the tropospheric phenomenon and to develop a calculation model for radiative transfer through the haze. Radiometric observations of the dust haze were analyzed for haze infrared transmission. Infrared and tropospheric cooling rates are given together with the haze volume absorption rate.

  14. Theoretical investigation of all-metal-based mushroom plasmonic metamaterial absorbers at infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Kimata, Masafumi

    2015-12-01

    High-performance wavelength-selective infrared (IR) sensors require small pixel structures, a low-thermal mass, and operation in the middle-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) regions for multicolor IR imaging. All-metal-based mushroom plasmonic metamaterial absorbers (MPMAs) were investigated theoretically and were designed to enhance the performance of wavelength-selective uncooled IR sensors. All components of the MPMAs are based on thin layers of metals such as Au without oxide insulators for increased absorption. The absorption properties of the MPMAs were investigated by rigorous coupled-wave analysis. Strong wavelength-selective absorption is realized over a wide range of MWIR and LWIR wavelengths by the plasmonic resonance of the micropatch and the narrow-gap resonance, without disturbance from the intrinsic absorption of oxide insulators. The absorption wavelength is defined mainly by the micropatch size and is longer than its period. The metal post width has less impact on the absorption properties and can maintain single-mode operation. Through-holes can be formed on the plate area to reduce the thermal mass. A small pixel size with reduced thermal mass and wideband single-mode operation can be realized using all-metal-based MPMAs.

  15. [Shaping of electron radiation fields using homogeneous absorbent materials].

    PubMed

    Eichhorn, M; Reis, A; Kraft, M

    1990-01-01

    Proof of shielding and forming by absorbers was done in water phantom dosimetrically. Alterations of isodose course were measured in dependence of primary energy, as well as of thickness and density of the absorber materials. Piacryl or aluminium are not suitable for forming of irregular electron fields. They only effect a reduction of therapeutic range. For primary energies of 10.0 less than or equal to MeV less than or equal to E0- less than or equal to 20.0 MeV lead rubber and wood metal are to recommended in a thickness of less than or equal to 10 mm or less than or equal to 8 mm respectively.

  16. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

    PubMed Central

    Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

    2015-01-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  17. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    PubMed

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.

  18. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    PubMed

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  19. Transport of infrared radiation in cuboidal clouds

    NASA Technical Reports Server (NTRS)

    Harshvardhan, MR.; Weinman, J. A.; Davies, R.

    1981-01-01

    The transport of infrared radiation in a single cuboidal cloud is modeled using a variable azimuth two-stream approximation. Computations are made at 10 microns for a Deirmendjian (1969) C-1 water cloud where the single scattering albedo is equal to 0.638 and the asymmetry parameter is 0.865. The results indicate that the emittance of the top face of the model cloud is always less than that for a plane parallel cloud of the same optical depth. The hemispheric flux escaping from the cloud top possesses a gradient from the center to the edges which are warmer when the cloud is over warmer ground. Cooling rate calculations in the 8-13.6 micron region demonstrate that there is cooling out of the sides of the cloud at all levels even when there is heating of the core from the ground below. The radiances exiting from model cuboidal clouds are computed by path integration over the source function obtained with the two-stream approximation. Results indicate that the brightness temperature measured from finite clouds will overestimate the cloud-top temperature.

  20. Semiconductor-doped glass saturable absorbers for near-infrared solid-state lasers

    NASA Astrophysics Data System (ADS)

    Malyarevich, A. M.; Yumashev, K. V.; Lipovskii, A. A.

    2008-04-01

    A survey of results on use of semiconductor-doped glass saturable absorbers for near-infrared passively mode-locked and Q-switched solid-state lasers is presented. Nanosized semiconductor particles (quantum dots) belong to quantum confined systems where motion of an electron and a hole is defined by the finite size of the nanoparticle. Dependence of the excitonic transition energy on the QDs size provides the possibility to tune the absorption of the glasses embedded with such particles to wavelength of specific light source. IV-VI semiconductor QDs (PbS, PbSe) are of interest for IR application due to their narrow band gap and large exciton Bohr radii. These allow for exciton absorption band at the wavelength through 1-3μm. Nonlinear optical properties of PbS, PbSe, and CuxSe nanoparticles embedded in glass matrices necessary for saturable absorber applications are analyzed. It is shown that these materials can be efficiently used for passive mode locking and Q switching of solid-state lasers based on Nd3+, Yb3+, Cr4+, Tm3+, and Ho3+ ions emitting through 1-2.1μm spectral range.

  1. Metamaterial Absorbers for Infrared Detection of Molecular Self-Assembled Monolayers

    PubMed Central

    Ishikawa, Atsushi; Tanaka, Takuo

    2015-01-01

    The emerging field of plasmonic metamaterials has introduced new degree of freedom to manipulate optical field from nano to macroscopic scale, offering an attractive platform for sensing applications. So far, metamaterial sensor concepts, however, have focused on hot-spot engineering to improve the near-field enhancement, rather than fully exploiting tailored material properties. Here, we present a novel spectroscopic technique based on the metamaterial infrared (IR) absorber allowing for a low-background detection scheme as well as significant plasmonic enhancement. Specifically, we experimentally demonstrate the resonant coupling of plasmonic modes of a metamaterial absorber and IR vibrational modes of a molecular self-assembled monolayer. The metamaterial consisting of an array of Au/MgF2/Au structures exhibits an anomalous absorption at ~3000 cm−1, which spectrally overlaps with C-H stretching vibrational modes. Symmetric/asymmetric C-H stretching modes of a 16-Mercaptohexadecanoic acid monolayer are clearly observed as Fano-like anti-resonance peaks within a broad plasmonic absorption of the metamaterial. Spectral analysis using Fano line-shape fitting reveals the underlying resonant interference in plasmon-molecular coupled systems. Our metamaterial approach achieves the attomole sensitivity with a large signal-to-noise ratio in the far-field measurement, thus may open up new avenues for realizing ultrasensitive IR inspection technologies. PMID:26229011

  2. Near-infrared absorbing boron-dibenzopyrromethenes that serve as light-harvesting sensitizers for polymeric solar cells.

    PubMed

    Kubo, Yuji; Watanabe, Kazuki; Nishiyabu, Ryuhei; Hata, Rieko; Murakami, Akinori; Shoda, Takayuki; Ota, Hitoshi

    2011-09-01

    Hexylthiophene-conjugated boron-dibenzopyrromethenes with benzo[1,3,2]oxazaborinine rings, 1, that absorb near-infrared light with relatively high molecular extinction coefficients have been synthesized. The incorporation of 3-hexylthiophene-conjugated dye 1a at a blend ratio of 5 wt % into a polymeric solar cell based on a P3HT/indene-C(70) bisadduct (IC(70)BA) bulk heterojunction structure improved power conversion efficiency from 3.7 to 4.3%. The present work suggests that well-defined near-infrared absorbing BODIPY analogues can potentially be used as photosensitizers in polymeric solar cells.

  3. Evidence for Solar Cycle Influence on the Infrared Energy Budget and Radiative Cooling of the Thermosphere

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Martin-Torres, F. Javier; Marshall, B. Thomas; Thompson, R. Earl; Williams, Joshua; Turpin, TImothy; Kratz, D. P.; Russell, James M.; Woods, Tom; Gordley, Larry L.

    2007-01-01

    We present direct observational evidence for solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere. By analyzing nearly five years of data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, we show that the annual mean infrared power radiated by the nitric oxide (NO) molecule at 5.3 m has decreased by a factor of 2.9. This decrease is correlated (r = 0.96) with the decrease in the annual mean F10.7 solar index. Despite the sharp decrease in radiated power (which is equivalent to a decrease in the vertical integrated radiative cooling rate), the variability of the power as given in the standard deviation of the annual means remains approximately constant. A simple relationship is shown to exist between the infrared power radiated by NO and the F10.7 index, thus providing a fundamental relationship between solar activity and the thermospheric cooling rate for use in thermospheric models. The change in NO radiated power is also consistent with changes in absorbed ultraviolet radiation over the same time period.

  4. Space Radiation Absorbed Dose Distribution in a Human Phantom Torso

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Yang, T.; Atwell, W.

    2000-01-01

    The flight of a human phantom torso with head that containing active dosimeters at 5 organ sites and 1400 TLDs distributed in 34 1" thick sections is described. Experimental dose rates and quality factors are compared with calculations for shielding distributions at the sites using the Computerized Anatomical Male (CAM) model. The measurements were complemented with those obtained from other instruments. These results have provided the most comprehensive data set to map the dose distribution inside a human and to assess the accuracy of radiation transport models and astronaut radiation risk.

  5. Effect of Index of Refraction on Radiation Characteristics in a Heated Absorbing, Emitting, and Scattering Layer

    NASA Technical Reports Server (NTRS)

    Siegel, R.; Spuckler, C. M.

    1992-01-01

    The effect of the index of refraction on the temperature distribution and radiative heat flux in semitransparent materials, such as some ceramics, is investigated analytically. In the case considered here, a plane layer of a ceramic material is subjected to external radiative heating incident on each of its surfaces; the material emits, absorbs, and isotropically scatters radiation. It is shown that, for radiative equilibrium in a gray layer with diffuse interfaces, the temperature distribution and radiative heat flux for any index of refraction can be obtained in a simple manner from the results for an index of refraction of unity.

  6. Blackbody Infrared Radiative Dissociation of Protonated Oligosaccharides

    NASA Astrophysics Data System (ADS)

    Fentabil, Messele A.; Daneshfar, Rambod; Kitova, Elena N.; Klassen, John S.

    2011-12-01

    The dissociation pathways, kinetics, and energetics of protonated oligosaccharides in the gas phase were investigated using blackbody infrared radiative dissociation (BIRD). Time-resolved BIRD measurements were performed on singly protonated ions of cellohexaose (Cel6), which is composed of β-(1 → 4)-linked glucopyranose rings, and five malto-oligosaccharides (Malx, where x = 4-8), which are composed of α-(1 → 4)-linked glucopyranose units. At the temperatures investigated (85-160 °C), the oligosaccharides dissociate at the glycosidic linkages or by the loss of a water molecule to produce B- or Y-type ions. The Y ions dissociate to smaller Y or B ions, while the B ions yield exclusively smaller B ions. The sequential loss of water molecules from the smallest B ions (B1 and B2) also occurs. Rate constants for dissociation of the protonated oligosaccharides and the corresponding Arrhenius activation parameters (Ea and A) were determined. The Ea and A-factors measured for protonated Malx (x > 4) are indistinguishable within error (~19 kcal mol-1, 1010 s-1), which is consistent with the ions being in the rapid energy exchange limit. In contrast, the Arrhenius parameters for protonated Cel6 (24 kcal mol-1, 1012 s-1) are significantly larger. These results indicate that both the energy and entropy changes associated with the glycosidic bond cleavage are sensitive to the anomeric configuration. Based on the results of this study, it is proposed that formation of B and Y ions occurs through a common dissociation mechanism, with the position of the proton establishing whether a B or Y ion is formed upon glycosidic bond cleavage.

  7. Soft and broadband infrared metamaterial absorber based on gold nanorod/liquid crystal hybrid with tunable total absorption

    NASA Astrophysics Data System (ADS)

    Su, Zhaoxian; Yin, Jianbo; Zhao, Xiaopeng

    2015-11-01

    We design a soft infrared metamaterial absorber based on gold nanorods dispersed in liquid crystal (LC) placed on a gold film and theoretically investigate its total absorption character. Because the nanorods align with the LC molecule, the gold nanorods/LC hybrid exhibits different permittivity as a function of tilt angle of LC. At a certain tilt angle, the absorber shows an omnidirectional total absorption effect. By changing the tilt angle of LC by an external electric field, the total absorption character can be adjusted. The total absorption character also depends on the concentration, geometric dimension of nanorods, and defect of nanorod arrangement in LC. When the LC contains different size of gold nanorods, a broadband absorption can be easily realized. The characteristics including flexibility, omnidirectional, broadband and tunablility make the infrared metamaterial absorber possess potential use in smart metamaterial devices.

  8. Soft and broadband infrared metamaterial absorber based on gold nanorod/liquid crystal hybrid with tunable total absorption

    PubMed Central

    Su, Zhaoxian; Yin, Jianbo; Zhao, Xiaopeng

    2015-01-01

    We design a soft infrared metamaterial absorber based on gold nanorods dispersed in liquid crystal (LC) placed on a gold film and theoretically investigate its total absorption character. Because the nanorods align with the LC molecule, the gold nanorods/LC hybrid exhibits different permittivity as a function of tilt angle of LC. At a certain tilt angle, the absorber shows an omnidirectional total absorption effect. By changing the tilt angle of LC by an external electric field, the total absorption character can be adjusted. The total absorption character also depends on the concentration, geometric dimension of nanorods, and defect of nanorod arrangement in LC. When the LC contains different size of gold nanorods, a broadband absorption can be easily realized. The characteristics including flexibility, omnidirectional, broadband and tunablility make the infrared metamaterial absorber possess potential use in smart metamaterial devices. PMID:26576660

  9. The effect of clouds on the earth's solar and infrared radiation budgets

    NASA Technical Reports Server (NTRS)

    Herman, G. F.; Wu, M.-L. C.; Johnson, W. T.

    1980-01-01

    The effect of global cloudiness on the solar and infrared components of the earth's radiation balance is studied in general circulation model experiments. A wintertime simulation is conducted in which the cloud radiative transfer calculations use realistic cloud optical properties and are fully interactive with model-generated cloudiness. This simulation is compared to others in which the clouds are alternatively non-interactive with respect to the solar or thermal radiation calculations. Other cloud processes (formation, latent heat release, precipitation, vertical mixing) were accurately simulated in these experiments. It is concluded that on a global basis clouds increase the global radiation balance by 40 W/sq m by absorbing longwave radiation, but decrease it by 56 W/sq m by reflecting solar radiation to space. The net cloud effect is therefore a reduction of the radiation balance by 16 W/sq m, and is dominated by the cloud albedo effect. Changes in cloud frequency and distribution and in atmospheric and land temperatures are also reported for the control and for the non-interactive simulations. In general, removal of the clouds' infrared absorption cools the atmosphere and causes additional cloudiness to occur, while removal of the clouds' solar radiative properties warms the atmosphere and causes fewer clouds to form. It is suggested that layered clouds and convective clouds over water enter the climate system as positive feedback components, while convective clouds over land enter as negative components.

  10. Dual-band uncooled infrared sensors employing Fano resonance in plasmonic absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Takagawa, Yousuke; Kimata, Masafumi

    2016-05-01

    Wavelength-selective uncooled infrared (IR) sensors have significant advantages with regard to applications such as fire detection, gas analysis, hazardous materials recognition, and biological analysis. We have previously demonstrated an uncooled IR sensor based on a two-dimensional plasmonic absorber (2D PLA) that exhibited wavelength-selective absorption over a wide range spanning the middle and long-wavelength IR regions. This device had a Au-based 2D periodic dimple-array structure, in which surface plasmon modes were induced, leading to wavelength-selective absorption, such that the absorption wavelength was determined by the period of the surface dimples. However, dual-band operation based on this concept has not yet been investigated, even though the ability to absorb in two different wavelength bands is extremely important for object recognition. In the present study, a dual-band uncooled IR sensor was developed using a 2D PLA with asymmetric dimple periods (2-D PLA-AP). To achieve multiband absorption, the Au-based dimples in this device were fabricated so as to have different periods in the orthogonal x and y directions. Theoretical calculations predicted asymmetric absorption spectra, attributed to Fano resonance in the 2-D PLA-AP. A sensor was subsequently fabricated using complementary metal oxide semiconductor and micromachining techniques. Measurement of the spectral responsivity demonstrated that selective absorption occurred in two different wavelength bands, determined by the dimple periods in the x and y directions. The results obtained in this study will be applicable to the development of advanced sensors capable of multiband detection in the IR region.

  11. Synchrotron radiation as an infrared source.

    PubMed

    Stevenson, J R; Ellis, H; Bartlett, R

    1973-12-01

    The increasing availability of synchrotron radiation sources in a number of geographical regions of the world has motivated an evaluation of the radiation from electron accelerators and storage rings as a possible source for ir spectroscopy. As synchrotron radiation can be analytically described, a direct comparison is made with blackbody radiation for typical solid state spectroscopy. Both existing and proposed synchrotron radiation sources are found to be attractive in the ir. The ultrahigh vacuum environment of the source is compatible with clean surface investigations, the analytical description of the radiation is appropriate for calibration studies, and the continuous nature is suitable for Fourier spectroscopy or whenever a white light source is desirable.

  12. [Characteristics of infrared radiation of meridians and acupoints].

    PubMed

    Zheng, Juan-Juan; Shen, Xue-Yong; Zhao, Yi

    2010-10-01

    Infrared radiation temperature and characteristics of infrared spectrum of meridians and acupoints are summarized in this article. The infrared radiant track along the running course of meridians might be a ubiquitous phenomenon of the vital activity. The high temperature bands below the meridian lines at the cuticular layer are often taken as the manifestation of the tract. It could be induced by various stimulations on acupoints with warm-needling as the best causative method. High temperature and low resistance are considered as 2 features of the acupoint zone. The adenosine-triphosphate energy metabolism of the acupoint zone is higher than the non-point zone, which indicates that essential physiological and pathological information are carried by infrared radiation temperature of acupoint and infrared spectrum of acupoint. However, it is realized that study on characteristics of infrared radiation only is far from enough to reveal the essence of meridians and acupoints. And much still remains to be done in strengthening basic studies of characteristics of infrared radiation, structure pattern of meridians and acupoints as well as volt-ampere characteristics.

  13. Reduced radiation-absorbed dose to tissues with partial panoramic radiography for evaluation of third molars.

    PubMed

    Kircos, L T; Eakle, W S; Smith, R A

    1986-05-01

    The radiation-absorbed doses from panoramic radiography, distal molar radiography, and a partial panoramic radiographic technique that exposes only the third molar region to radiation are compared. Doses of radiation to the submandibular salivary gland were comparable by all three techniques, but doses of radiation to the head and neck were reduced greatly by the partial panoramic radiographic technique. Partial panoramic radiography is a diagnostically satisfactory and a radiologically safer technique for evaluation of third molar pathosis than is panoramic or distal molar radiography. PMID:3458783

  14. Reduced radiation-absorbed dose to tissues with partial panoramic radiography for evaluation of third molars

    SciTech Connect

    Kircos, L.T.; Eakle, W.S.; Smith, R.A.

    1986-05-01

    The radiation-absorbed doses from panoramic radiography, distal molar radiography, and a partial panoramic radiographic technique that exposes only the third molar region to radiation are compared. Doses of radiation to the submandibular salivary gland were comparable by all three techniques, but doses of radiation to the head and neck were reduced greatly by the partial panoramic radiographic technique. Partial panoramic radiography is a diagnostically satisfactory and a radiologically safer technique for evaluation of third molar pathosis than is panoramic or distal molar radiography.

  15. 3-μm Mid-infrared pulse generation using topological insulator as the saturable absorber.

    PubMed

    Li, Jianfeng; Luo, Hongyu; Wang, Lele; Zhao, Chujun; Zhang, Han; Li, Heping; Liu, Yong

    2015-08-01

    We report an 1150-nm diode-pump passively Q-switched Ho3+-doped ZBLAN fiber laser using topological insulator (TI): Bi2Te3 as the saturable absorber (SA). The TI: Bi2Te3 prepared using the cost-effective hydrothermal intercalation/exfoliation method was dropped onto a CaF2 substrate to fabricate the free-space SA component. It has a low saturable peak intensity of 2.12  MW/cm2 and a high modulation depth of 51.3% measured at 2 μm. Inserting this component into a linear-cavity Ho3+-doped ZBLAN fiber laser, stable Q-switched pulses at 2979.9 nm were obtained with the repetition rate of 81.96 kHz and pulse duration of 1.37 μs. The achieved maximum output power and pulse energy were 327.4 mW at a slope efficiency of 11.6% and 3.99 μJ, respectively, only limited by the available pump power. Our work reveals that the TIs are absolutely a class of promising and reliable SAs for pulse generation at 3-μm mid-infrared waveband. PMID:26258382

  16. Colloidal metasurfaces displaying near-ideal and tunable light absorbance in the infrared.

    PubMed

    Rozin, Matthew J; Rosen, David A; Dill, Tyler J; Tao, Andrea R

    2015-01-01

    Metasurfaces are ultrathin, two-dimensional arrays of subwavelength resonators that have been demonstrated to control the flow of light in ways that are otherwise unattainable with natural materials. These arrays are typically composed of metallic Ag or Au nanostructures shaped like split rings, nanowire pairs or nanorods (commonly referred to as meta-atoms) that are arranged to produce a collective optical response spanning an impressive range of properties, from the perfect absorption of incident light to superresolution imaging. However, metasurfaces pose major challenges in their fabrication over large areas, which can be prohibitively expensive and time consuming using conventional nanolithography techniques. Here we show that differently shaped colloidal nanocrystals can be organized into metasurface architectures using robust, scalable assembly methods. These metasurfaces exhibit extreme in-plane electromagnetic coupling that is strongly dependent on nanocrystal size, shape and spacing. Colloidal metasurfaces that display near-ideal electromagnetic absorbance can be tuned from the visible into the mid-infrared wavelengths. PMID:26099835

  17. 3-μm Mid-infrared pulse generation using topological insulator as the saturable absorber.

    PubMed

    Li, Jianfeng; Luo, Hongyu; Wang, Lele; Zhao, Chujun; Zhang, Han; Li, Heping; Liu, Yong

    2015-08-01

    We report an 1150-nm diode-pump passively Q-switched Ho3+-doped ZBLAN fiber laser using topological insulator (TI): Bi2Te3 as the saturable absorber (SA). The TI: Bi2Te3 prepared using the cost-effective hydrothermal intercalation/exfoliation method was dropped onto a CaF2 substrate to fabricate the free-space SA component. It has a low saturable peak intensity of 2.12  MW/cm2 and a high modulation depth of 51.3% measured at 2 μm. Inserting this component into a linear-cavity Ho3+-doped ZBLAN fiber laser, stable Q-switched pulses at 2979.9 nm were obtained with the repetition rate of 81.96 kHz and pulse duration of 1.37 μs. The achieved maximum output power and pulse energy were 327.4 mW at a slope efficiency of 11.6% and 3.99 μJ, respectively, only limited by the available pump power. Our work reveals that the TIs are absolutely a class of promising and reliable SAs for pulse generation at 3-μm mid-infrared waveband.

  18. Detection Wavelength Control of Uncooled Infrared Sensors Using Two-Dimensional Lattice Plasmonic Absorbers

    PubMed Central

    Takagawa, Yousuke; Ogawa, Shinpei; Kimata, Masafumi

    2015-01-01

    Wavelength-selective uncooled infrared (IR) sensors are highly promising for a wide range of applications, such as fire detection, gas analysis and biomedical analysis. We have recently developed wavelength-selective uncooled IR sensors using square lattice two-dimensional plasmonic absorbers (2-D PLAs). The PLAs consist of a periodic 2-D lattice of Au-based dimples, which allow photons to be manipulated using surface plasmon modes. In the present study, a detailed investigation into control of the detection wavelength was conducted by varying the PLA lattice structure. A comparison was made between wavelength-selective uncooled IR sensors with triangular and square PLA lattices that were fabricated using complementary metal oxide semiconductor and micromachining techniques. Selective enhancement of the responsivity could be achieved, and the detection wavelength for the triangular lattice was shorter than that for the square lattice. The results indicate that the detection wavelength is determined by the reciprocal-lattice vector for the PLAs. The ability to control the detection wavelength in this manner enables the application of such PLAs to many types of thermal IR sensors. The results obtained here represent an important step towards multi-color imaging in the IR region. PMID:26067198

  19. Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

    SciTech Connect

    Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H.; Kinge, Sachin

    2015-10-12

    Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO{sub 2} layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10{sup −2} A W{sup −1} and a shot-derived specific detectivity of 3 × 10{sup 9} Jones at 1530 nm wavelength.

  20. Detection Wavelength Control of Uncooled Infrared Sensors Using Two-Dimensional Lattice Plasmonic Absorbers.

    PubMed

    Takagawa, Yousuke; Ogawa, Shinpei; Kimata, Masafumi

    2015-06-10

    Wavelength-selective uncooled infrared (IR) sensors are highly promising for a wide range of applications, such as fire detection, gas analysis and biomedical analysis. We have recently developed wavelength-selective uncooled IR sensors using square lattice two-dimensional plasmonic absorbers (2-D PLAs). The PLAs consist of a periodic 2-D lattice of Au-based dimples, which allow photons to be manipulated using surface plasmon modes. In the present study, a detailed investigation into control of the detection wavelength was conducted by varying the PLA lattice structure. A comparison was made between wavelength-selective uncooled IR sensors with triangular and square PLA lattices that were fabricated using complementary metal oxide semiconductor and micromachining techniques. Selective enhancement of the responsivity could be achieved, and the detection wavelength for the triangular lattice was shorter than that for the square lattice. The results indicate that the detection wavelength is determined by the reciprocal-lattice vector for the PLAs. The ability to control the detection wavelength in this manner enables the application of such PLAs to many types of thermal IR sensors. The results obtained here represent an important step towards multi-color imaging in the IR region.

  1. The interaction of infrared radiation with the eye: A review of the literature

    NASA Technical Reports Server (NTRS)

    Turner, H. S.

    1972-01-01

    A compilation of data concerning the effects of infrared radiation on the eye is presented. Information in the following areas is included: (1) transmission and absorption of infrared radiation by the ocular tissues, (2) range of infrared radiation which is harmful to the ocular tissues, (3) infrared radiation thresholds of the various oscular tissues, and (4) infrared radiation transmission and absorption of current optic materials.

  2. Electronic modulation of infrared radiation in graphene plasmonic resonators.

    PubMed

    Brar, Victor W; Sherrott, Michelle C; Jang, Min Seok; Kim, Seyoon; Kim, Laura; Choi, Mansoo; Sweatlock, Luke A; Atwater, Harry A

    2015-05-07

    All matter at finite temperatures emits electromagnetic radiation due to the thermally induced motion of particles and quasiparticles. Dynamic control of this radiation could enable the design of novel infrared sources; however, the spectral characteristics of the radiated power are dictated by the electromagnetic energy density and emissivity, which are ordinarily fixed properties of the material and temperature. Here we experimentally demonstrate tunable electronic control of blackbody emission from graphene plasmonic resonators on a silicon nitride substrate. It is shown that the graphene resonators produce antenna-coupled blackbody radiation, which manifests as narrow spectral emission peaks in the mid-infrared. By continuously varying the nanoresonator carrier density, the frequency and intensity of these spectral features can be modulated via an electrostatic gate. This work opens the door for future devices that may control blackbody radiation at timescales beyond the limits of conventional thermo-optic modulation.

  3. Electronic modulation of infrared radiation in graphene plasmonic resonators

    NASA Astrophysics Data System (ADS)

    Brar, Victor W.; Sherrott, Michelle C.; Jang, Min Seok; Kim, Seyoon; Kim, Laura; Choi, Mansoo; Sweatlock, Luke A.; Atwater, Harry A.

    2015-05-01

    All matter at finite temperatures emits electromagnetic radiation due to the thermally induced motion of particles and quasiparticles. Dynamic control of this radiation could enable the design of novel infrared sources; however, the spectral characteristics of the radiated power are dictated by the electromagnetic energy density and emissivity, which are ordinarily fixed properties of the material and temperature. Here we experimentally demonstrate tunable electronic control of blackbody emission from graphene plasmonic resonators on a silicon nitride substrate. It is shown that the graphene resonators produce antenna-coupled blackbody radiation, which manifests as narrow spectral emission peaks in the mid-infrared. By continuously varying the nanoresonator carrier density, the frequency and intensity of these spectral features can be modulated via an electrostatic gate. This work opens the door for future devices that may control blackbody radiation at timescales beyond the limits of conventional thermo-optic modulation.

  4. Electronic modulation of infrared radiation in graphene plasmonic resonators.

    PubMed

    Brar, Victor W; Sherrott, Michelle C; Jang, Min Seok; Kim, Seyoon; Kim, Laura; Choi, Mansoo; Sweatlock, Luke A; Atwater, Harry A

    2015-01-01

    All matter at finite temperatures emits electromagnetic radiation due to the thermally induced motion of particles and quasiparticles. Dynamic control of this radiation could enable the design of novel infrared sources; however, the spectral characteristics of the radiated power are dictated by the electromagnetic energy density and emissivity, which are ordinarily fixed properties of the material and temperature. Here we experimentally demonstrate tunable electronic control of blackbody emission from graphene plasmonic resonators on a silicon nitride substrate. It is shown that the graphene resonators produce antenna-coupled blackbody radiation, which manifests as narrow spectral emission peaks in the mid-infrared. By continuously varying the nanoresonator carrier density, the frequency and intensity of these spectral features can be modulated via an electrostatic gate. This work opens the door for future devices that may control blackbody radiation at timescales beyond the limits of conventional thermo-optic modulation. PMID:25948173

  5. Bandwidth control of wavelength-selective uncooled infrared sensors using two-dimensional plasmonic absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Kimata, Masafumi

    2016-05-01

    Although standard uncooled infrared (IR) sensors can be used to record information such as the shape, position, and average radiant intensity of objects, these devices cannot capture color (that is, wavelength) data. Achieving wavelength selectivity would pave the way for the development of advanced uncooled IR sensors capable of providing color information as well as multi-color image sensors that would have significant advantages in applications such as fire detection, gas analysis, hazardous material recognition, and biological analysis. We have previously demonstrated an uncooled IR sensor incorporating a two-dimensional plasmonic absorber (2D PLA) that exhibits wavelength selectivity over a wide range in the mid- and long-IR regions. This PLA has a 2D Au-based periodic array of dimples, in which surface plasmon modes are induced and wavelength-selective absorption occurs. However, the dependence of the absorption bandwidth on certain structural parameters has yet to be clarified. The bandwidth of such devices is a vital factor when considering the practical application of these sensors to tasks such as gas detection. In the present study, control of the bandwidth was theoretically investigated using a rigorous coupled wave analysis approach. It is demonstrated that the dimple sidewall structure has a significant impact on the bandwidth and can be used to control both narrow- and broadband absorption. Increasing the sidewall slope was found to decrease the bandwidth due to suppression of cavity-mode resonance in the depth direction of the dimples. These results will contribute to the development of high-resolution, wavelength-selective uncooled IR sensors.

  6. Infrared Radiation Filament And Metnod Of Manufacture

    DOEpatents

    Johnson, Edward A.

    1998-11-17

    An improved IR radiation source is provided by the invention. A radiation filament has a textured surface produced by seeded ion bombardment of a metal foil which is cut to a serpentine shape and mounted in a windowed housing. Specific ion bombardment texturing techniques tune the surface to maximize emissions in the desired wavelength range and to limit emissions outside that narrow range, particularly at longer wavelengths. A combination of filament surface texture, thickness, material, shape and power circuit feedback control produce wavelength controlled and efficient radiation at much lower power requirements than devices of the prior art.

  7. High speed infrared radiation thermometer, system, and method

    DOEpatents

    Markham, James R.

    2002-01-01

    The high-speed radiation thermometer has an infrared measurement wavelength band that is matched to the infrared wavelength band of near-blackbody emittance of ceramic components and ceramic thermal barrier coatings used in turbine engines. It is comprised of a long wavelength infrared detector, a signal amplifier, an analog-to-digital converter, an optical system to collect radiation from the target, an optical filter, and an integral reference signal to maintain a calibrated response. A megahertz range electronic data acquisition system is connected to the radiation detector to operate on raw data obtained. Because the thermometer operates optimally at 8 to 12 .mu.m, where emittance is near-blackbody for ceramics, interferences to measurements performed in turbine engines are minimized. The method and apparatus are optimized to enable mapping of surface temperatures on fast moving ceramic elements, and the thermometer can provide microsecond response, with inherent self-diagnostic and calibration-correction features.

  8. Polarimeter measures sea state characteristics using emitted infrared radiation

    NASA Technical Reports Server (NTRS)

    Egan, W. G.; Hilgeman, T.

    1977-01-01

    An infrared polarimeter, capable of operating between 1 and 12 micrometers wavelength has been used to measure the polarization of emitted radiation from the sea. The observed polarization at 10.6 micrometers from a smooth sea was found to be positive, indicating the dominance of reflected infrared sky radiation over the emitted. With the appearance of waves, the percent polarization increased, as expected, for a zenith angle well above the Brewster angle for water. This is qualitatively in accordance with a model presented to explain the behavior. Initial analyses indicate that the polarized components of the sea's emitted and reflected radiation are affected by type and direction of waves, angle of viewing, and foam. The effects of variations in these parameters require further delineation. The infrared polarimetric technique appears to be a novel new passive method for remote monitoring of waves.

  9. Dental Enamel Irradiated with Infrared Diode Laser and Photo-Absorbing Cream: Part 2—EDX Study

    PubMed Central

    dos Santos, Edson Aparecido Pereira; Soares, Luís Eduardo Silva; do Espírito Santo, Ana Maria; Martin, Airton Abrahão; Duarte, Danilo Antônio; Pacheco-Soares, Cristina; Brugnera, Aldo

    2009-01-01

    Abstract Objective: The effects of laser-induced compositional changes on the enamel were investigated by energy-dispersive X-ray fluorescence spectrometry (μ-EDX). After cariogenic challenge, we administered treatment of low-level infrared diode laser and a photo-absorbing cream (used to intensify the superficial light absorption). Background Data: Dental caries is considered the most prevalent oral disease. A simple and noninvasive caries preventive regimen is treating tooth enamel with a laser, either alone or in combination with fluoride, which reduces enamel solubility and dissolution rates. High power lasers are still not widely used in private practice. Low-power near-infrared lasers may be an alternative approach. Energy-dispersive μ-EDX is a versatile and nondestructive spectroscopic technique that allows for a qualitative and quantitative elemental analysis of inorganic enamel components, such as calcium and phosphorus. Materials and Methods: Twenty-four extracted or exfoliated caries-free deciduous molars were divided into six groups: 1) control group (CTR-no treatment); 2) infrared laser treatment (L) (λ = 810 nm, 100 mW/cm2, 90 sec, 4.47 J/cm2, 9 J); 3) infrared laser irradiation and photo-absorbing agent (CL); 4) photo-absorbing agent alone (C); 5) infrared laser irradiation and fluoridated photo-absorbing agent (FCL); and 6) fluoridated photo-absorbing agent alone (FC). Samples were analyzed using μ-EDX after two sets of treatments and pH cycling cariogenic challenges. Results: The CL group showed statistically significant increases in calcium and phosphorus (wt%) compared with the CTR group. The Ca/P ratio was similar in the FCL and CTR groups. There was a significant laser-induced reduction compared with the CTR group, and there was a possible modification of the organic balance content in enamel treated with laser and cream. Conclusion: μ-EDX may be able to detect compositional changes in mineral phases of lased enamel under

  10. Infrared radiative energy transfer in gaseous systems

    NASA Technical Reports Server (NTRS)

    Tiwari, Surendra N.

    1991-01-01

    Analyses and numerical procedures are presented to investigate the radiative interactions in various energy transfer processes in gaseous systems. Both gray and non-gray radiative formulations for absorption and emission by molecular gases are presented. The gray gas formulations are based on the Planck mean absorption coefficient and the non-gray formulations are based on the wide band model correlations for molecular absorption. Various relations for the radiative flux and divergence of radiative flux are developed. These are useful for different flow conditions and physical problems. Specific plans for obtaining extensive results for different cases are presented. The procedure developed was applied to several realistic problems. Results of selected studies are presented.

  11. Investigation of Infra-red and Nonequilibrium Air Radiation

    NASA Technical Reports Server (NTRS)

    Kruger, Charles H.; Laux, Christophe O.

    1994-01-01

    This report summarizes the results obtained during a research program on the infrared radiation of air plasmas conducted in the High Temperature Gasdynamics Laboratory at Stanford University. This program was intended to investigate the masking of infrared signatures by the air plasma formed behind the bow shock of high velocity missiles. Prior to this work, the radiative emission of air plasmas in the infrared had been the object of few experimental investigations, and although several infrared systems were already modeled in radiation codes such as NEQAIR, measurements were required to validate numerical predictions and indicate whether all transitions of importance were accounted for in the model. The program was further motivated by the fact that 9 excited states (A, B, C, D, B', F, H, and H') of NO radiate in the infrared, especially between 1 and 1.5 microns where at least 9 transitions involving can be observed. Because these IR transitions are relatively well separated from each other, excited NO states concentrations can be easily measured, thus providing essential information on excited-state chemistry for use in optical diagnostics or in electronic excitation model validation. Detailed comparisons between measured and simulated spectra are presented.

  12. Infrared Radiation from Comet Hale-Bopp

    NASA Astrophysics Data System (ADS)

    Wickramasinghe, Chandra; Hoyle, Fred

    The infrared spectrum of Comet Hale-Bopp over the wavelength range 7.5 to 45 micrometers, obtained when it was at a heliocentric distance of 2.9 AU, is shown to be consistent with a model dominated by a mixed microbial culture including diatoms with an approximately 10% mass contribution from crystalline olivine. Crystalline olivine by itself is unable to account for the data.

  13. Far infrared radiation (FIR): its biological effects and medical applications

    PubMed Central

    Vatansever, Fatma; Hamblin, Michael R.

    2013-01-01

    Far infrared (FIR) radiation (λ = 3–100 μm) is a subdivision of the electromagnetic spectrum that has been investigated for biological effects. The goal of this review is to cover the use of a further sub-division (3– 12 μm) of this waveband, that has been observed in both in vitro and in vivo studies, to stimulate cells and tissue, and is considered a promising treatment modality for certain medical conditions. Technological advances have provided new techniques for delivering FIR radiation to the human body. Specialty lamps and saunas, delivering pure FIR radiation (eliminating completely the near and mid infrared bands), have became safe, effective, and widely used sources to generate therapeutic effects. Fibers impregnated with FIR emitting ceramic nanoparticles and woven into fabrics, are being used as garments and wraps to generate FIR radiation, and attain health benefits from its effects. PMID:23833705

  14. Far infrared radiation (FIR): its biological effects and medical applications.

    PubMed

    Vatansever, Fatma; Hamblin, Michael R

    2012-11-01

    Far infrared (FIR) radiation (λ = 3-100 μm) is a subdivision of the electromagnetic spectrum that has been investigated for biological effects. The goal of this review is to cover the use of a further sub-division (3- 12 μm) of this waveband, that has been observed in both in vitro and in vivo studies, to stimulate cells and tissue, and is considered a promising treatment modality for certain medical conditions. Technological advances have provided new techniques for delivering FIR radiation to the human body. Specialty lamps and saunas, delivering pure FIR radiation (eliminating completely the near and mid infrared bands), have became safe, effective, and widely used sources to generate therapeutic effects. Fibers impregnated with FIR emitting ceramic nanoparticles and woven into fabrics, are being used as garments and wraps to generate FIR radiation, and attain health benefits from its effects.

  15. Transfer of infrared radiation through clouds.

    PubMed

    Kuhn, P M; Weickmann, H K; Lojko, M J; Stearns, L P

    1974-03-01

    Calculations of radiative through and resulting ir cooling of cloud forms is certainly more difficult than observations. Based on observations, a radiative transfer model has been developed for absorption in clouds employing an observationally determined volume absorption coefficient, ranging from 0.0005 to 0.0007 cm(-1). This model does not require any assumption of cloud blackness or thickness and permits clouds to remain partially transparent or opaque as their thickness and absorption dictate. Agreement within a standard deviation of 12.0 W m(-2) between observation and calculation has been maintained in approximately twenty profiles through clouds. The standard deviation was determined from some 140 observations.

  16. Temperature and hydration effects on absorbance spectra and radiation sensitivity of a radiochromic medium

    SciTech Connect

    Rink, Alexandra; Lewis, David F.; Varma, Sangya; Vitkin, I. Alex; Jaffray, David A.

    2008-10-15

    The effects of temperature on real time changes in optical density ({Delta}OD) of GAFCHROMIC EBT film were investigated. The spectral peak of maximum change in absorbance ({lambda}{sub max}) was shown to downshift linearly when the temperature of the film was increased from 22 to 38 degree sign C. The {Delta}OD values were also shown to decrease linearly with temperature, and this decrease could not be attributed to the shift in {lambda}{sub max}. A compensation scheme using {lambda}{sub max} and a temperature-dependent correction factor was investigated, but provided limited improvement. Part of the reason may be the fluctuations in hydration of the active component, which were found to affect both position of absorbance peaks and the sensitivity of the film. To test the effect of hydration, laminated and unlaminated films were desiccated. This shifted both the major and minor absorbance peaks in the opposite direction to the change observed with temperature. The desiccated film also exhibited reduced sensitivity to ionizing radiation. Rehydration of the desiccated films did not reverse the effects, but rather gave rise to another form of the polymer with absorbance maxima upshifted further 20 nm. Hence, the spectral characteristics and sensitivity of the film can be dependent on its history, potentially complicating both real-time and conventional radiation dosimetry.

  17. Temperature and hydration effects on absorbance spectra and radiation sensitivity of a radiochromic medium

    PubMed Central

    Rink, Alexandra; Lewis, David F.; Varma, Sangya; Vitkin, I. Alex; Jaffray, David A.

    2008-01-01

    The effects of temperature on real time changes in optical density (ΔOD) of GAFCHROMIC® EBT film were investigated. The spectral peak of maximum change in absorbance (λmax) was shown to downshift linearly when the temperature of the film was increased from 22 to 38 °C. The ΔOD values were also shown to decrease linearly with temperature, and this decrease could not be attributed to the shift in λmax. A compensation scheme using λmax and a temperature-dependent correction factor was investigated, but provided limited improvement. Part of the reason may be the fluctuations in hydration of the active component, which were found to affect both position of absorbance peaks and the sensitivity of the film. To test the effect of hydration, laminated and unlaminated films were desiccated. This shifted both the major and minor absorbance peaks in the opposite direction to the change observed with temperature. The desiccated film also exhibited reduced sensitivity to ionizing radiation. Rehydration of the desiccated films did not reverse the effects, but rather gave rise to another form of the polymer with absorbance maxima upshifted further 20 nm. Hence, the spectral characteristics and sensitivity of the film can be dependent on its history, potentially complicating both real-time and conventional radiation dosimetry. PMID:18975701

  18. Characterizing SixNy absorbers and support beams for far-infrared/submillimeter transition-edge sensors

    NASA Astrophysics Data System (ADS)

    Beyer, A. D.; Kenyon, M. E.; Echternach, P. M.; Eom, B.-H.; Bueno, J.; Day, P. K.; Bock, J. J.; Bradford, C. M.

    2010-07-01

    We report on the characterization of SixNy (Si-N) optical absorbers and support beams for transition-edge sensors (TESs). The absorbers and support beams measured are suitable to meet ultra-sensitive noise equivalent power (NEP<=10-19W/√Hz) and effective response time (τ) requirements (τ<=100ms) for space-borne far-infrared( IR)/submillimeter(sub-mm) spectrometers, such as the Background Limited far-Infrared/Sub-mm Spectrograph (BLISS) and the SpicA FAR-infrared Instrument (SAFARI) for the SPace Infrared telescope for Cosmology and Astrophysics (SPICA). The thermal response time (τ0) of an absorber suspended by support beams from a lowtemperature substrate depends on the heat capacity (C) of the absorber and the thermal conductance (G) of the support beams (τ0=C/G). In membrane-isolated TESs for BLISS, the effective response time τ is expected to be a factor of 20 smaller than τ0 because of voltage-biased electrothermal feedback operation and assumption of a reasonable open-loop gain, LI~20. We present design specifications for the arrays of membrane-isolated ultra-sensitive TESs for BLISS. Additionally, we measured G and τ0 for two Si-N noise thermometry device (NTD) architectures made using different fabrication processes: (1) a solid membrane Si-N absorber suspended by thin and long Si-N support beams and (2) a wire-mesh Si-N absorber suspended by long, and even thinner, Si-N support beams. The measurements of G and τ0 were designed to test suitability of the Si-N thermal performance to meet the demands of the two SPICA instruments. The solid membrane NTD architecture is similar to the TES architecture for SAFARI and the mesh membrane NTD is similar to that of BLISS TESs. We report measured values of G and C for several BLISS and SAFARI NTD devices. We observe that the heat capacity of the solid membrane devices can be reduced to the order of 1fJ/K at 65mK for devices that are wet etched by KOH. However, C for these devices is found to be on the order

  19. Surface deformation of a thin liquid film under infrared radiation

    NASA Astrophysics Data System (ADS)

    Cui, Nai-Yi

    2013-11-01

    A thin layer of decane liquid floating above the surface of water is compressed in thickness when exposed to a radiation by an infrared laser in normal incidence. This is believed to result from an inward radiation pressure received by the decane film as light crosses successively the air-decane interface and the decane-water interface. The experimental results support Abraham's formulation for the momentum of light. Thermo-effects may also contribute.

  20. Unphysical consequences of negative absorbed power in linear passive scattering: Implications for radiation force and torque.

    PubMed

    Marston, Philip L; Zhang, Likun

    2016-06-01

    Contrary to some claims, the absorbed power associated with linear scattering of sound by passive objects in ideal fluids must be non-negative. Such unphysical claims suggest analytical or computational error, or use of an unphysical constitutive relation for material properties. The close connection with the evaluation of acoustic radiation force on targets according to Westervelt's formulation [J. Acoust. Soc. Am. 29, 26-29 (1957)], recently generalized to certain acoustic beams, is briefly reviewed along with the theory of acoustic radiation torque on axisymmetric targets with power absorption. Applications to viscous dissipation and to issues pertaining to active targets are also examined. PMID:27369138

  1. Cooling systems and hybrid A/C systems using an electromagnetic radiation-absorbing complex

    DOEpatents

    Halas, Nancy J.; Nordlander, Peter; Neumann, Oara

    2015-05-19

    A method for powering a cooling unit. The method including applying electromagnetic (EM) radiation to a complex, where the complex absorbs the EM radiation to generate heat, transforming, using the heat generated by the complex, a fluid to vapor, and sending the vapor from the vessel to a turbine coupled to a generator by a shaft, where the vapor causes the turbine to rotate, which turns the shaft and causes the generator to generate the electric power, wherein the electric powers supplements the power needed to power the cooling unit

  2. Rectenna that converts infrared radiation to electrical energy

    DOEpatents

    Davids, Paul; Peters, David W.

    2016-09-06

    Technologies pertaining to converting infrared (IR) radiation to DC energy are described herein. In a general embodiment, a rectenna comprises a conductive layer. A thin insulator layer is formed on the conductive layer, and a nanoantenna is formed on the thin insulator layer. The thin insulator layer acts as a tunnel junction of a tunnel diode.

  3. Quality Characteristics of Dried Bananas Produced with Infrared Radiation Technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Browning of fruits during drying is a major quality concern. The enzyme polyphenol oxidase has been found to be the main cause of browning in bananas. Infrared radiation (IR) drying could be used to minimize enzymatic browning hence eliminating the need for pre-treatments. This study was to inves...

  4. Feasibility of Jujube peeling using novel infrared radiation heating technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infrared (IR) radiation heating has a promising potential to be used as a sustainable and effective method to eliminate the use of water and chemicals in the jujube-peeling process and enhance the quality of peeled products. The objective of this study was to investigate the feasibility of use IR he...

  5. Novel radiator for carbon dioxide absorbents in low-flow anesthesia.

    PubMed

    Hirabayashi, Go; Mitsui, Takanori; Kakinuma, Takayasu; Ogihara, Yukihiko; Matsumoto, Shohei; Isshiki, Atsushi; Yasuo, Watanabe

    2003-01-01

    During long-term low-flow sevoflurane anesthesia, dew formation and the generation of compound A are increased in the anesthesia circuit because of elevated soda lime temperature. The object of this study was to develop a novel radiator for carbon dioxide absorbents used for long durations of low-flow sevoflurane anesthesia. Eleven female swine were divided into two groups comprising a "radiator" group (n = 5) that used a novel radiator for carbon dioxide absorbents and a "control" group (n = 6) that used a conventional canister. Anesthesia was maintained with N2O, O2, and sevoflurane, and low-flow anesthesia was performed with fresh gas flow at 0.6 L/min for 12 hr. In the "control" group, the soda lime temperature reached more than 40 degrees C and soda lime dried up with severe dew formation in the inspiratory valve. In the "radiator" group, the temperature of soda lime stayed at 30 degrees C, and the water content of soda lime was retained with no dew formation in the inspiratory valve. In addition, compound A concentration was reduced. In conclusion, radiation of soda lime reduced the amounts of condensation formed and the concentration of compound A in the anesthetic circuit, and allowed long term low-flow anesthesia without equipment malfunction.

  6. Search for the Cosmic Infrared Background Radiation using COBE Data

    NASA Technical Reports Server (NTRS)

    Hauser, Michael

    2001-01-01

    This project was initiated to allow completion of the primary investigation of the Diffuse Infrared Background Experiment (DIRBE) on NASA's Cosmic Background Explorer (CORE) mission, and to study the implications of those findings. The Principal Investigator (PI) on this grant was also the Principal Investigator on the DIRBE team. The project had two specific goals: Goal 1: Seek improved limits upon, or detections of, the cosmic infrared background radiation using data from the COBE Diffuse Infrared Background Experiment (DIRBE). Goal 2: Explore the implications of the limits and measured values of the cosmic infrared background for energy releases in the Universe since the formation of the first luminous sources. Both of these goals have been successfully accomplished.

  7. Infrared Radiography: Modeling X-ray Imaging Without Harmful Radiation

    NASA Astrophysics Data System (ADS)

    Zietz, Otto; Mylott, Elliot; Widenhorn, Ralf

    2015-01-01

    Planar x-ray imaging is a ubiquitous diagnostic tool and is routinely performed to diagnose conditions as varied as bone fractures and pneumonia. The underlying principle is that the varying attenuation coefficients of air, water, tissue, bone, or metal implants within the body result in non-uniform transmission of x-ray radiation. Through the detection of transmitted radiation, the spatial organization and composition of materials in the body can be ascertained. In this paper, we describe an original apparatus that teaches these concepts by utilizing near infrared radiation and an up-converting phosphorescent screen to safely probe the contents of an opaque enclosure.

  8. Hot spot generation in energetic materials created by long-wavelength infrared radiation

    SciTech Connect

    Chen, Ming-Wei; You, Sizhu; Suslick, Kenneth S.; Dlott, Dana D.

    2014-02-10

    Hot spots produced by long-wavelength infrared (LWIR) radiation in an energetic material, crystalline RDX (1,3,5-trinitroperhydro-1,3,5-triazine), were studied by thermal-imaging microscopy. The LWIR source was a CO{sub 2} laser operating in the 28-30 THz range. Hot spot generation was studied using relatively low intensity (∼100 W cm{sup −2}), long-duration (450 ms) LWIR pulses. The hot spots could be produced repeatedly in individual RDX crystals, to investigate the fundamental mechanisms of hot spot generation by LWIR, since the peak hot-spot temperatures were kept to ∼30 K above ambient. Hot spots were generated preferentially beneath RDX crystal planes making oblique angles with the LWIR beam. Surprisingly, hot spots were more prominent when the LWIR wavelength was tuned to be weakly absorbed (absorption depth ∼30 μm) than when the LWIR wavelength was strongly absorbed (absorption depth ∼5 μm). This unexpected effect was explained using a model that accounts for LWIR refraction and RDX thermal conduction. The weakly absorbed LWIR is slightly focused underneath the oblique crystal planes, and it penetrates the RDX crystals more deeply, increasing the likelihood of irradiating RDX defect inclusions that are able to strongly absorb or internally focus the LWIR beam.

  9. Estimation of surface melt and absorbed radiation on the Greenland ice sheet using passive microwave data

    NASA Astrophysics Data System (ADS)

    Joshi, Maneesha D.

    1999-09-01

    Passive microwave data from the Defense Meteorological Satellite Program (DMPS) Special Sensor Microwave/Imager (SSM/I) and Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) were used to estimate the extent of melt, melt duration and length of melt season on the Greenland ice sheet for the years 1979--1997. Three techniques---a maximum likelihood classification (MLC), a spectral technique and an edge detection method---were implemented. The MLC and spectral techniques provided estimates of the melt extent, while estimates of the melt extent, the length of the melt season and the duration of melt were obtained from the edge method. Comparisons of the surface melt results with global and coastal (Greenland) temperature data indicated that melt extents were better related to global than coastal temperatures. The reverse was noted for melt season and duration trends. The results suggest an overall increase in warmer spells in summer for the period 1979--1997, as indicated by increasing maximum melt extent on the ice sheet. However, there was no corresponding increase in the overall total melt season and total duration of melt. The annual melt extent and the total melt season/duration showed a sharp drop in 1992, due to the eruption of Mt. Pinatubo in June, 1991. The results indicated that melt extents alone cannot be used to estimate warming or cooling on the ice sheet and that melt duration and season trends should also be examined. These surface melt results were then extended to obtain the absorbed radiation flux on the Greenland ice sheet. The monthly albedo on the ice sheet was estimated by assigning an albedo value that was a function of the length of the melt season. The monthly albedo was used with a solar radiation model to estimate the monthly and annual absorbed shortwave flux on the ice sheet. The computation of absorbed radiation on the Greenland ice sheet gave results consistent with those derived from the Earth Radiation Budget Experiment (ERBE

  10. Investigation of jewelry powders radiating far-infrared rays and the biological effects on human skin.

    PubMed

    Yoo, B H; Park, C M; Oh, T J; Han, S H; Kang, H H; Chang, I S

    2002-01-01

    Far-infrared rays have certain kinds of effects on the human body, especially on skin, blood circulation, and skin cell vitalizing. Some jewelry powders radiate far-infrared rays. Jade has powerful far-infrared ray radiation, and tourmaline has pyroelectric and piezoelectric properties and radiated far-infrared rays. The jewelry powders (fine powdered jade and tourmaline powders) were screened by far-infrared rays for radiation properties and tested for the effects of far-infrared rays on the human skin by temperature observation using an infrared thermal analyzer. PMID:12053208

  11. Investigation of jewelry powders radiating far-infrared rays and the biological effects on human skin.

    PubMed

    Yoo, B H; Park, C M; Oh, T J; Han, S H; Kang, H H; Chang, I S

    2002-01-01

    Far-infrared rays have certain kinds of effects on the human body, especially on skin, blood circulation, and skin cell vitalizing. Some jewelry powders radiate far-infrared rays. Jade has powerful far-infrared ray radiation, and tourmaline has pyroelectric and piezoelectric properties and radiated far-infrared rays. The jewelry powders (fine powdered jade and tourmaline powders) were screened by far-infrared rays for radiation properties and tested for the effects of far-infrared rays on the human skin by temperature observation using an infrared thermal analyzer.

  12. Research on remote sensing of broadband absorbers by using near-infrared diode lasers.

    PubMed

    Geng, Hui; Liu, Jian-Guo; He, Yabai; Zhang, Yu-Jun; Xu, Zhen-Yu; Ruan, Jun; Yao, Lu; Kan, Rui-Feng

    2014-10-01

    This paper reports the development of an experimental technique for optical remote sensing of broadband absorbers in ambient air. Broadband absorbers have been difficult to detect due to a lack of narrow absorption features, which makes it hard to separate them from interference with other absorbing species and background. In combination with a multidimensional linear regression procedure, we have developed a further step to correct for water vapor and background influences. Various physical processes limiting the detection sensitivity were studied and solutions were developed to reduce their influences. Although the received optical signal from backscatter was very weak as no corner cube reflector was used, we have demonstrated the technique on remote sensing of broadband absorption of ethanol vapor in ambient air with a moderate detection limit of 200 ppm · m. This portable handheld system is particularly suitable for quick "point-and-measure" applications. The developed technique is also applicable for detection of other broadband absorbers.

  13. 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.

  14. Surface-enhanced molecular spectroscopy (SEMS) based on perfect-absorber metamaterials in the mid-infrared.

    PubMed

    Li, Yongqian; Su, Lei; Shou, Chen; Yu, Chunmeng; Deng, Jinjun; Fang, Yu

    2013-01-01

    Surface-enhanced infrared absorption spectroscopy has attracted increased attention for direct access to molecular vibrational fingerprints in the mid-infrared. Perfect-absorber metamaterials (PAMs) with multi-band spectral responses and significant enhancement of the local near-field intensity were developed to improve the intrinsic absorption cross sections of absorption spectrum to identify the vibrational spectra of biomolecules. To verify its performance, the proposed infrared PAM array was used to identify the molecular stretches of a Parylene C film. The resonant responses of the infrared PAMs were accurately tuned to the vibrational modes of the C = C target bonds. The vibrational stretches of the C = C moiety were observed and the auto-fluorescence mechanisms of the Parylene C film were monitored. The unique properties of the PAMs indicate that this approach is a promising strategy for surface-enhanced molecular absorption spectroscopy (SEMS) in the mid-infrared region and for the tracking of characteristic molecular vibrational modes. PMID:24091778

  15. Surface-enhanced molecular spectroscopy (SEMS) based on perfect-absorber metamaterials in the mid-infrared

    PubMed Central

    Li, Yongqian; Su, Lei; Shou, Chen; Yu, Chunmeng; Deng, Jinjun; Fang, Yu

    2013-01-01

    Surface-enhanced infrared absorption spectroscopy has attracted increased attention for direct access to molecular vibrational fingerprints in the mid-infrared. Perfect-absorber metamaterials (PAMs) with multi-band spectral responses and significant enhancement of the local near-field intensity were developed to improve the intrinsic absorption cross sections of absorption spectrum to identify the vibrational spectra of biomolecules. To verify its performance, the proposed infrared PAM array was used to identify the molecular stretches of a Parylene C film. The resonant responses of the infrared PAMs were accurately tuned to the vibrational modes of the C = C target bonds. The vibrational stretches of the C = C moiety were observed and the auto-fluorescence mechanisms of the Parylene C film were monitored. The unique properties of the PAMs indicate that this approach is a promising strategy for surface-enhanced molecular absorption spectroscopy (SEMS) in the mid-infrared region and for the tracking of characteristic molecular vibrational modes. PMID:24091778

  16. Near-infrared-absorbing gold nanopopcorns with iron oxide cluster core for magnetically amplified photothermal and photodynamic cancer therapy.

    PubMed

    Bhana, Saheel; Lin, Gan; Wang, Lijia; Starring, Hunter; Mishra, Sanjay R; Liu, Gang; Huang, Xiaohua

    2015-06-01

    We present the synthesis and application of a new type of dual magnetic and plasmonic nanostructures for magnetic-field-guided drug delivery and combined photothermal and photodynamic cancer therapy. Near-infrared-absorbing gold nanopopcorns containing a self-assembled iron oxide cluster core were prepared via a seed-mediated growth method. The hybrid nanostructures are superparamagnetic and show great photothermal conversion efficiency (η=61%) under near-infrared irradiation. Compact and stable nanocomplexes for photothermal-photodynamic therapy were formed by coating the nanoparticles with near-infrared-absorbing photosensitizer silicon 2,3-naphthalocyannie dihydroxide and stabilization with poly(ethylene glycol) linked with 11-mercaptoundecanoic acid. The nanocomplex showed enhanced release and cellular uptake of the photosensitizer with the use of a gradient magnetic field. In vitro studies using two different cell lines showed that the dual mode photothermal and photodynamic therapy with the assistance of magnetic-field-guided drug delivery dramatically improved the therapeutic efficacy of cancer cells as compared to the combination treatment without using a magnetic field and the two treatments alone. The "three-in-one" nanocomplex has the potential to carry therapeutic agents deep into a tumor through magnetic manipulation and to completely eradicate tumors by subsequent photothermal and photodynamic therapies without systemic toxicity.

  17. Biological activities caused by far-infrared radiation

    NASA Astrophysics Data System (ADS)

    Inoué, Shojiro; Kabaya, Morihiro

    1989-09-01

    Contrary to previous presumption, accumulated evidence indicates that far-infrared rays are biologically active. A small ceramic disk that emist far-infrared rays (4 16 μm) has commonly been applied to a local spot or a whole part of the body for exposure. Pioneering attempts to experimentally analyze an effect of acute and chronic radiation of far-infrared rays on living organisms have detected a growth-promoting effect in growing rats, a sleep-modulatory effect in freely behaving rats and an insomiac patient, and a blood circulation-enhancing effect in human skin. Question-paires to 542 users of far-infrared radiator disks embedded in bedelothes revealed that the majority of the users subjectively evaluated an improvement of their health. These effects on living organisms appear to be non-specifically triggered by an exposure to far-infrared rays, which eventually induce an increase in temperature of the body tissues or, more basically, an elevated motility of body fluids due to decrease in size of water clusters.

  18. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of the- art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments. This approach can lead to large loss of water and a significant mass penalty for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. The optimal system is based on a trade-off between the mass of water saved and extra power needed to regenerate the LiCl absorber. This paper describes analysis models and the predicted performance and optimize the size of the SEAR system, estimated size and mass of key components, and power requirements for regeneration. We also present a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  19. Estimation of radiation absorbed doses to the red marrow in radioimmunotherapy

    SciTech Connect

    Macey, D.J.; DeNardo, S.J.; DeNardo, G.L.; DeNardo, D.A.; Sui Shen

    1995-02-01

    Myelotoxicity is the dose-limiting factor in radioimmunotherapy. Traditional methods most commonly used to estimate the radiation adsorbed dose to the bone marrow of patients consider contribution from radionuclide in the blood and/or total body. Targeted therapies, such as radioimmunotherapy, add a third potential source for radiation to the bone marrow because the radiolabeled targeting molecules can accumulate specifically on malignant target cells infiltrating the bone marrow. A non-invasive method for estimating the radiation absorbed dose to the red marrow of patients who have received radiolabeled monoclonal antibodies (MoAb) has been developed and explored. The method depends on determining the cumulated activity in three contributing sources: (1) marrow; (2) blood; and (3) total body. The novel aspect of this method for estimating marrow radiation dose is derivation of the radiation dose for the entire red marrow from radiation dose estimates obtained by detection of cumulated activity in three lumbar vertebrae using a gamma camera. Contributions to the marrow radiation dose form marrow, blood, and total body cumulated activity were determined for patients who received an I-131 labeled MoAb, Lym-1, that reacts with malignant B-lymphocytes of chronic lymphocytic leukemia and nonHodgkin`s lymphoma. Six patients were selected for illustrative purposes because their vertebrae were readily visualized on lumbar images. 32 refs., 6 figs., 1 tab.

  20. Infrared radiative transfer in the dust-free Martian atmosphere

    SciTech Connect

    Crisp, D. )

    1990-08-30

    Gases in the Martian atmosphere, including CO{sub 2}, H{sub 2}O, CO, and O{sub 3}, combine to produce some absorption at most infrared wavelengths. Line-by-line and quasi-random models are used to derive synthetic spectra of dust-free Martian atmospheres. These spectra show where gases absorb most strongly and provide a baseline for comparison with the results from more complete models that include the effects of dust. Gas absorption and emission features at many infrared wavelengths provide a source of contamination that must be removed from remote sensing observations of the Martian surface. For example, the weak reflectance minimum observed at wavelengths near 2.35 {mu}m, which has been interpreted as evidence for a variety of surface materials, is produced almost entirely by atmospheric CO and CO{sub 2} absorption. Isotopic CO{sub 2} bands near 7 and 8 {mu}m and near-infrared water vapor absorption bands partially overlap strong carbonate and hydrate features and frustrate systematic spectroscopic searches for these important candidate surface materials on Mars. In other spectral regions, gas absorption bands provide opportunities to study the structure and composition of the Martian atmosphere. Computed radiances within the strong CO{sub 2} 15-{mu}m band are incorporated into an atmospheric retrieval algorithm to derive the atmospheric temperature structure from Mariner 9 IRIS observations. Absorption and emission by gases also contributes to the energetics of the Martian atmosphere. Near-infrared CO{sub 2} bands absorb enough sunlight to produce globally-averaged solar heating rates that vary from 1 K/Earth day at the surface, to 10 K/Earth day at pressures near 0.01 mbar. Other gases contribute 1-5% of the heating at some levels.

  1. Fabrication of an Absorber-Coupled MKID Detector and Readout for Sub-Millimeter and Far-Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Brown, Ari-David; Hsieh, Wen-Ting; Moseley, S. Harvey; Stevenson, Thomas R.; U-yen, Kongpop; Wollack, Edward J.

    2010-01-01

    We have fabricated absorber-coupled microwave kinetic inductance detector (MKID) arrays for sub-millimeter and far-infrared astronomy. Each detector array is comprised of lambda/2 stepped impedance resonators, a 1.5 micrometer thick silicon membrane, and 380 micrometer thick silicon walls. The resonators consist of parallel plate aluminum transmission lines coupled to low impedance Nb microstrip traces of variable length, which set the resonant frequency of each resonator. This allows for multiplexed microwave readout and, consequently, good spatial discrimination between pixels in the array. The Al transmission lines simultaneously act to absorb optical power and are designed to have a surface impedance and filling fraction so as to match the impedance of free space. Our novel fabrication techniques demonstrate high fabrication yield of MKID arrays on large single crystal membranes and sub-micron front-to-back alignment of the microstrip circuit.

  2. Generating Far-Infrared Radiation By Two-Wave Mixing

    NASA Technical Reports Server (NTRS)

    Borenstain, Shmuel

    1992-01-01

    Far-infrared radiation 1 to 6 GHz generated by two-wave mixing in asymmetrically grown GaAs/AlxGa1-xAs multiple-quantum-well devices. Two near-infrared semiconductor diode lasers phase-locked. Outputs amplified, then combined in semiconductor nonlinear multiple-quantum-well planar waveguide. Necessary to optimize design of device with respect to three factors: high degree of confinement of electromagnetic field in nonlinear medium to maximize power density, phase matching to extend length of zone of interaction between laser beams in non-linear medium, and nonlinear susceptibility. Devices used as tunable local oscillators in heterodyne-detection radiometers.

  3. 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.

  4. Sensitivity of radiation absorbed in the ocean to atmospheric and oceanic parameters in the short wavelength region. I - Cloudless atmosphere

    NASA Astrophysics Data System (ADS)

    Masuda, Kazuhiko; Takashima, Tsutomu

    1988-08-01

    The effects of atmospheric and oceanic parameters on the measured shortwave radiation absorbed in the ocean and on the upward irradiance at the top of the atmosphere were investigated using a model atmosphere-ocean system under the conditions of cloudless atmosphere. The computations showed that, for theta(0) of about 45 deg, the absorbed radiation in the ocean depends mainly on the atmospheric turbidity. Precipitable water vapor and ozone in the atmosphere also affect the absorbed radiation, but they have little effect on the upward irradiance. The surface roughness and whitecaps have little effect on the absorbed radiation or the upward radiance if the surface wind speed is less than about 5 m/sec. Finally, the oceanic hydrosols have little effect on either of these characteristics except when they are of pure scattering type in a turbid condition.

  5. Infrared Signature Masking by Air Plasma Radiation

    NASA Technical Reports Server (NTRS)

    Kruger, C. H.; Laux, C. O.

    1998-01-01

    Detailed measurements and modeling of the spectral emission of an atmospheric pressure air plasma at temperatures up to -3400 K have been made. The cold gas injected in the plasma torch contained an estimated mole fraction of water vapor of approximately 4.5 x 10(exp -3) and an estimated carbon dioxide mole fraction of approximately 3.3 x 10(exp -4). Under these conditions, the minimum level of air plasma emission is found to be between 3.9 and 4.15 microns. Outside this narrow region, significant spectral emission is detected that can be attributed to the fundamental and overtone bands of NO and OH, and to the v(sub 3) and the (v(sub 1)+v(sub 3)) bands Of CO2. Special attention was paid to the effects of ambient air absorption in the optical path between the plasma and the detector. Excellent quantitative agreement is obtained between the measured and simulated spectra, which are both on absolute intensity scales, thus lending confidence in the radiation models incorporated into NEQAIR2-IR over the course of this research program.

  6. Effect of Index of Refraction on Radiation Characteristics in a Heated Absorbing, Emitting, and Scattering Layer

    NASA Technical Reports Server (NTRS)

    Siegel, R.; Spuckler, C. M.

    1992-01-01

    The index of refraction can considerably influence the temperature distribution and radiative heat flow in semitransparent materials such as some ceramics. For external radiant heating, the refractive index influences the amount of energy transmitted into the interior of the material. Emission within a material depends on the square of its refractive index, and hence this emission can be many times that for a biackbody radiating into a vacuum. Since radiation exiting through an interface into a vacuum cannot exceed that of a blackbody, there is extensive reflection at the internal surface of an interface, mostly by total internal reflection. This redistributes energy within the layer and tends to make its temperature distribution more uniform. The purpose of the present analysis is to show that, for radiative equilibrium in a gray layer with diffuse interfaces, the temperature distribution and radiative heat flux for any index of refraction can be obtained very simply from the results for an index of refraction of unity. For the situation studied here, the layer is subjected to external radiative heating incident on each of its surfaces. The material emits, absorbs, and isotropically scatters radiation. For simplicity the index of refraction is unity in the medium surrounding the layer. The surfaces of the layer are assumed diffuse. This is probably a reasonable approximation for a ceramic layer that has not been polished. When transmitted radiation or radiation emitted from the interior reaches the inner surface of an interface, the radiation is diffused and some of it thereby placed into angular directions for which there is total internal reflection. This provides a trapping effect for retaining energy within the layer and tends to equalize its temperature distribution. An analysis of temperature distributions in absorbing-emitting layers, including index of refraction effects, was developed by Gardon (1958) to predict cooling and heat treating of glass plates

  7. Independently tunable dual-band perfect absorber based on graphene at mid-infrared frequencies.

    PubMed

    Zhang, Yuping; Li, Tongtong; Chen, Qi; Zhang, Huiyun; O'Hara, John F; Abele, Ethan; Taylor, Antoinette J; Chen, Hou-Tong; Azad, Abul K

    2015-01-01

    We design a dual-band absorber formed by combining two cross-shaped metallic resonators of different sizes within a super-unit-cell arranged in mirror symmetry. Simulations indicate that absorption efficiencies greater than 99% can be achieved at two different frequencies under normal incidence. We employ a design scheme with graphene integration, which allows independent tuning of individual absorption frequencies by electrostatically changing the Fermi energy of the graphene layer. High absorbance is maintained over a wide incident angle range up to 50 degrees for both TE and TM polarizations. It thus enables a promising way to design electrically tunable absorbers, which may contribute toward the realization of frequency selective detectors for sensing applications.

  8. Independently tunable dual-band perfect absorber based on graphene at mid-infrared frequencies

    DOE PAGES

    Zhang, Yuping; Li, Tongtong; Chen, Qi; Zhang, Huiyun; O’Hara, John F.; Abele, Ethan; Taylor, Antoinette J.; Chen, Hou-Tong; Azad, Abul K.

    2015-12-22

    We design a dual-band absorber formed by combining two cross-shaped metallic resonators of different sizes within a super-unit-cell arranged in mirror symmetry. Simulations indicate that absorption efficiencies greater than 99% can be achieved at two different frequencies under normal incidence. We also employ a design scheme with graphene integration, which allows independent tuning of individual absorption frequencies by electrostatically changing the Fermi energy of the graphene layer. High absorbance is maintained over a wide incident angle range up to 50 degrees for both TE and TM polarizations. Thus, it enables a promising way to design electrically tunable absorbers, which maymore » contribute toward the realization of frequency selective detectors for sensing applications.« less

  9. Independently tunable dual-band perfect absorber based on graphene at mid-infrared frequencies

    SciTech Connect

    Zhang, Yuping; Li, Tongtong; Chen, Qi; Zhang, Huiyun; O’Hara, John F.; Abele, Ethan; Taylor, Antoinette J.; Chen, Hou-Tong; Azad, Abul K.

    2015-12-22

    We design a dual-band absorber formed by combining two cross-shaped metallic resonators of different sizes within a super-unit-cell arranged in mirror symmetry. Simulations indicate that absorption efficiencies greater than 99% can be achieved at two different frequencies under normal incidence. We also employ a design scheme with graphene integration, which allows independent tuning of individual absorption frequencies by electrostatically changing the Fermi energy of the graphene layer. High absorbance is maintained over a wide incident angle range up to 50 degrees for both TE and TM polarizations. Thus, it enables a promising way to design electrically tunable absorbers, which may contribute toward the realization of frequency selective detectors for sensing applications.

  10. Independently tunable dual-band perfect absorber based on graphene at mid-infrared frequencies

    NASA Astrophysics Data System (ADS)

    Zhang, Yuping; Li, Tongtong; Chen, Qi; Zhang, Huiyun; O'Hara, John F.; Abele, Ethan; Taylor, Antoinette J.; Chen, Hou-Tong; Azad, Abul K.

    2015-12-01

    We design a dual-band absorber formed by combining two cross-shaped metallic resonators of different sizes within a super-unit-cell arranged in mirror symmetry. Simulations indicate that absorption efficiencies greater than 99% can be achieved at two different frequencies under normal incidence. We employ a design scheme with graphene integration, which allows independent tuning of individual absorption frequencies by electrostatically changing the Fermi energy of the graphene layer. High absorbance is maintained over a wide incident angle range up to 50 degrees for both TE and TM polarizations. It thus enables a promising way to design electrically tunable absorbers, which may contribute toward the realization of frequency selective detectors for sensing applications.

  11. Independently tunable dual-band perfect absorber based on graphene at mid-infrared frequencies

    PubMed Central

    Zhang, Yuping; Li, Tongtong; Chen, Qi; Zhang, Huiyun; O’Hara, John F.; Abele, Ethan; Taylor, Antoinette J.; Chen, Hou-Tong; Azad, Abul K.

    2015-01-01

    We design a dual-band absorber formed by combining two cross-shaped metallic resonators of different sizes within a super-unit-cell arranged in mirror symmetry. Simulations indicate that absorption efficiencies greater than 99% can be achieved at two different frequencies under normal incidence. We employ a design scheme with graphene integration, which allows independent tuning of individual absorption frequencies by electrostatically changing the Fermi energy of the graphene layer. High absorbance is maintained over a wide incident angle range up to 50 degrees for both TE and TM polarizations. It thus enables a promising way to design electrically tunable absorbers, which may contribute toward the realization of frequency selective detectors for sensing applications. PMID:26689917

  12. Broadening of absorption band by coupled gap plasmon resonances in a near-infrared metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Cong, Jiawei; Yao, Hongbing; Gong, Daolei; Chen, Mingyang; Tong, Yanqun; Fu, Yonghong; Ren, Naifei

    2016-07-01

    We propose a strategy to broaden the absorption band of the conventional metamaterial absorber by incorporating alternating metal/dielectric films. Up to 7-fold increase in bandwidth and ∼95% average absorption are achieved arising from the coupling of induced multiple gap plasmon resonances. The resonance coupling is analytically demonstrated using the coupled oscillator model, which reveals that both the optimal coupling strength and the resonance wavelength matching are required for the enhancement of absorption bandwidth. The presented multilayer design is easily fabricated and readily implanted to other absorber configurations, offering a practical avenue for applications in photovoltaic cells and thermal emitters.

  13. Verification of absorbed dose using diodes in cobalt-60 radiation therapy.

    PubMed

    Gadhi, Muhammad Asghar; Fatmi, Shahab; Chughtai, Gul M; Arshad, Muhammad; Shakil, Muhammad; Rahmani, Uzma Mahmood; Imran, Malik Younas; Buzdar, Saeed Ahmad

    2016-03-01

    The objective of this work was to enhance the quality and safety of dose delivery in the practice of radiation oncology. To achieve this goal, the absorbed dose verification program was initiated by using the diode in vivo dosimetry (IVD) system (for entrance and exit). This practice was implemented at BINO, Bahawalpur, Pakistan. Diodes were calibrated for making absorbed dose measurements. Various correction factors (SSD, dose non-linearity, field size, angle of incidence, and wedge) were determined for diode IVD system. The measurements were performed in phantom in order to validate the IVD procedure. One hundred and nineteen patients were monitored and 995 measurements were performed. For phantom, the percentage difference between measured and calculated dose for entrance setting remained within ±2% and for exit setting ±3%. For patient measurements, the percentage difference between measured and calculated dose remained within ±5% for entrance/open fields and ±7% for exit/wedge/oblique fields. One hundred and nineteen patients and 995 fields have been monitored during the period of 6 months. The analysis of all available measurements gave a mean percent deviation of ±1.19% and standard deviation of ±2.87%. Larger variations have been noticed in oblique, wedge and exit measurements. This investigation revealed that clinical dosimetry using diodes is simple, provides immediate results and is a useful quality assurance tool for dose delivery. It has enhanced the quality of radiation dose delivery and increased/improved the reliability of the radiation therapy practice in BINO.

  14. Theoretical model of infrared radiation of dressed human body indoors

    NASA Astrophysics Data System (ADS)

    Xiong, Zonglong; Yang, Kuntao

    2008-02-01

    The human body detecting by infrared thermography plays an important role in the field of medical treatment, scout and rescuing work after disaster occuring. The infrared image theoretical model is a foundation for a human body detecting because it can improve the ability and efficiency. The essence and significance of the information on the temperature field of the human body in indoor environment is systematically discussed on the basis of physical structure and thermoregulation system. The various factors that influence the body temperature are analyzed, then the method for the calculation of temperature distribution of the surface temperature is introduced. On the basis of the infrared radiation theory, a theoretical model is proposed to calculate the radiant flux intensity of the human body. This model can be applied to many fields.

  15. Broadband infrared vibrational nano-spectroscopy using thermal blackbody radiation.

    PubMed

    O'Callahan, Brian T; Lewis, William E; Möbius, Silke; Stanley, Jared C; Muller, Eric A; Raschke, Markus B

    2015-12-14

    Infrared vibrational nano-spectroscopy based on scattering scanning near-field optical microscopy (s-SNOM) provides intrinsic chemical specificity with nanometer spatial resolution. Here we use incoherent infrared radiation from a 1400 K thermal blackbody emitter for broadband infrared (IR) nano-spectroscopy. With optimized interferometric heterodyne signal amplification we achieve few-monolayer sensitivity in phonon polariton spectroscopy and attomolar molecular vibrational spectroscopy. Near-field localization and nanoscale spatial resolution is demonstrated in imaging flakes of hexagonal boron nitride (hBN) and determination of its phonon polariton dispersion relation. The signal-to-noise ratio calculations and analysis for different samples and illumination sources provide a reference for irradiance requirements and the attainable near-field signal levels in s-SNOM in general. The use of a thermal emitter as an IR source thus opens s-SNOM for routine chemical FTIR nano-spectroscopy. PMID:26698997

  16. Lageos orbit decay due to infrared radiation from earth

    NASA Technical Reports Server (NTRS)

    Rubincam, David Parry

    1987-01-01

    Infrared radiation from the earth may be the principal reason for the decay of Lageos' orbit. The radiation heats up the laser retroreflectors embedded in Lageos' aluminum surface. This creates a north-south temperature gradient on the satellite. The gradient in turn causes a force to be exerted on Lageos because of recoil from photons leaving its surface. The delayed heating of the retroreflectors due to their thermal inertia gives the force a net along-track component which always acts like drag. A simple thermal model for the retroreflectors indicates that this thermal drag accounts for about half the observed average along-track acceleration of -3.3 x 10 to the -10th power m/sec squared. The contribution from the aluminum surface to this effect is negligible. The infrared effect cannot explain the large observed fluctuations in drag which occur mainly when the orbit intersects the earth's shadow.

  17. Lageos orbit decay due to infrared radiation from Earth

    NASA Technical Reports Server (NTRS)

    Rubincam, David Parry

    1987-01-01

    Infrared radiation from the Earth may be the principal reason for the decay of Lageos' orbit. The radiation heats up the laser retroreflectors embedded in Lageos' aluminum surface. This creates a north-south temperature gradient on the satellite. The gradient in turn causes a force to be exerted on Lageos because of recoil from photons leaving its surface. The delayed heating of the retroreflectors due to their thermal inertia gives the force a net along-track component which always acts like drag. A simple thermal model for the retroreflectors indicates that this thermal drag accounts for about half the observed average along-track acceleration of -3.3 x 10 to the -10 power m/sec squared. The contribution from the aluminum surface to this effect is negligible. The infrared effect cannot explain the large observed fluctuations in drag which occur mainly when the orbit intersects the Earth's shadow.

  18. High field CdS detector for infrared radiation

    NASA Technical Reports Server (NTRS)

    Tyagi, R. C.; Robertson, J. B.; Boer, K. W.; Hadley, H. C., Jr. (Inventor)

    1974-01-01

    An infrared radiation detector including a cadmium sulfide platelet having a cathode formed on one of its ends and an anode formed on its other end is presented. The platelet is suitably doped such that stationary high-field domains are formed adjacent the cathode when based in the negative differential conductivity region. A negative potential is applied to the cathode such that a high-field domain is formed adjacent to the cathode. A potential measuring probe is located between the cathode and the anode at the edge of the high-field domain and means are provided for measuring the potential at the probe whereby this measurement is indicative of the infrared radiation striking the platelet.

  19. The Influence of Light Absorbing Aerosols on the Radiation Balance Over Central Greenland

    NASA Astrophysics Data System (ADS)

    Strellis, B.; Bergin, M. H.; Sokolik, I. N.; Dibb, J. E.; Sheridan, P. J.; Ogren, J. A.

    2011-12-01

    The Arctic region has proven to be more responsive to recent changes in climate than other parts of the Earth. A key component of the Arctic climate is the Greenland Ice Sheet, which has the potential to dramatically influence both sea level, depending on the amount of melting that occurs, and climate, through shifts in the regional radiation balance. Light absorbing aerosols from biomass burning, fossil fuel combustion, and dust sources can potentially have a significant impact on the radiation balance of the ice sheet, although at this time we lack the key measurements needed to accurately quantify aerosol forcing over the ice sheet. For this reason a field study was conducted at Summit, Greenland, from May-July of 2012. Our efforts included real-time measurements of aerosol physical and optical properties including size distribution, multi-wavelength scattering (σsp) and backscattering (σbsp) coefficients, and multi-wavelength absorption coefficient (σap), as well as measurements of wavelength dependent aerosol optical depth and spectral snow albedo. The measurements serve as inputs to a radiative transfer model to estimate the direct aerosol radiative forcing at both the surface and top of the atmosphere. Preliminary results indicate that the direct aerosol radiative forcing is often several Wm-2 and is at times greater than 10 Wm-2. The aerosol chemical composition (major ions, elements, and organic and elemental carbon compounds) was also determined through filter sampling and will be discussed in terms of the sources of light absorbing aerosols over central Greenland.

  20. Investigation of infra-red and nonequilibrium air radiation

    NASA Technical Reports Server (NTRS)

    Kruger, Charles H.

    1995-01-01

    This report describes progress on the first year of a research program on the infrared radiation of air plasmas conducted in the High Temperature Gasdynamics Laboratory at Stanford University. This program is intended to investigate the masking of infrared signatures by the air plasma formed behind the bow shock of high velocity missiles. To this date, the radiative emission of air plasmas in the infrared has been the object of few experimental investigations, and although several infrared systems are already modeled in radiation codes such as NEQAIR, measurements are required to validate numerical predictions and indicate whether all transitions of importance are accounted for. The present program is motivated by the fact that 9 excited states (A, B, C, D, B', F, H, and H') of NO radiate in the infrared, especially between 1 and 1.5 microns where at least 9 transitions involving can be observed. Because these IR transitions are relatively well separated from each other, excited NO states concentrations can be easily measured, thus providing essential information on excited-state chemistry for use in optical diagnostics or in electronic excitation model validation. Developing accurate collisional-radiative models for these excited NO states is of importance as the UV-VUV transitions of NO (beta, gamma, epsilon, beta prime, gamma prime) produce a major, if not dominant, fraction of the radiation emitted by air plasmas. During the first year of the program, research has focused on the spectral range 1.0 to 1.5 microns, as detailed in Section 2 of this report. The measurements, conducted in a 50 kW radio-frequency inductively coupled plasma torch operating on air at atmospheric pressure, extend previous shock tube investigations by Wray to a wider spectral range (1.0 to 1.5 microns vs 0.9 to 1.2 microns) and higher temperatures (7600 K in the plasma torch versus 6700 K in the shock-tube). These higher temperatures in the present experiment have made it possible to

  1. Effects of ultraviolet radiation, visible light, and infrared radiation on erythema and pigmentation: a review.

    PubMed

    Sklar, Lindsay R; Almutawa, Fahad; Lim, Henry W; Hamzavi, Iltefat

    2013-01-01

    The effects of ultraviolet radiation, visible light, and infrared radiation on cutaneous erythema, immediate pigment darkening, persistent pigment darkening, and delayed tanning are affected by a variety of factors. Some of these factors include the depth of cutaneous penetration of the specific wavelength, the individual skin type, and the absorption spectra of the different chromophores in the skin. UVB is an effective spectrum to induce erythema, which is followed by delayed tanning. UVA induces immediate pigment darkening, persistent pigment darkening, and delayed tanning. At high doses, UVA (primarily UVA2) can also induce erythema in individuals with skin types I-II. Visible light has been shown to induce erythema and a tanning response in dark skin, but not in fair skinned individuals. Infrared radiation produces erythema, which is probably a thermal effect. In this article we reviewed the available literature on the effects of ultraviolet radiation, visible light, and infrared radiation on the skin in regards to erythema and pigmentation. Much remains to be learned on the cutaneous effects of visible light and infrared radiation.

  2. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of-the-art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments, and or heavy phase change material heat exchangers for thermal storage. These approaches can lead to large loss of water and a significant mass penalties for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. This paper describes analysis models to predict performance and optimize the size of the SEAR system, estimated size and mass of key components, and an assessment of potential mass savings compared with alternative thermal management approaches. We also describe a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  3. Triple-layer Fabry-Perot/SPP aluminum absorber in the visible and near-infrared region.

    PubMed

    Shu, Shiwei; Li, Yang Yang

    2015-03-15

    We report a theoretical study on a novel type of absorber that can achieve near perfect absorption in the visible and near-infrared regions by utilizing the Fabry-Perot and the surface plasmon polariton (SPP) effects. The absorber consists of an Al/dielectric/Al triple-layered structure with the top Al layer consisting of an array of holes. The absorption features can be easily controlled by tuning the structural parameters, particularly the porous features of the top Al layer. When the porous features in the top Al layer are significantly smaller than the wavelength, light absorption is enabled through the Fabry-Perot effect. On the other hand, when the porous features in the top layer are at the subwavelength scale, new absorption peaks emerge due to the SPP effect. Furthermore, when the top Al layer consists of an array of hollow rings, the electric field at the interface between the top Al layer and the middle dielectric layer is greatly enhanced due to the plasmonic effect, indicating that the absorber reported here may be suitable for novel applications, e.g., the surface-enhanced Raman spectroscopy (SERS) substrates.

  4. Atlas of albedo and absorbed solar radiation derived from Nimbus 6 earth radiation budget data set, July 1975 to May 1978

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis; Bess, T. Dale; Rutan, David

    1989-01-01

    An atlas of monthly mean global contour maps of albedo and absorbed solar radiation is presented. The atlas is based on 35 months of continuous measurements from July 1975 through May 1978. The data were retrieved from measurements made by the shortwave wide field-of-view radiometer of the first Earth Radiation Budget (ERB) instrument, which flew on the Nimbus 6 spacecraft in 1975. Profiles of zonal mean albedos and absorbed solar radiation are tabulated. These geographical distributions are provided as a resource for studying the radiation budget of the earth. This atlas of albedo and absorbed solar radiation complements the atlases of outgoing longwave radiation by Bess and Smith in NASA-RP-1185 and RP-1186, also based on the Nimbus 6 and 7 ERB data.

  5. A universal design to realize a tunable perfect absorber from infrared to microwaves.

    PubMed

    Smaali, Rafik; Omeis, Fatima; Moreau, Antoine; Taliercio, Thierry; Centeno, Emmanuel

    2016-01-01

    We propose a design for an universal absorber, characterized by a resonance frequency that can be tuned from visible to microwave frequencies independently of the choice of the metal and the dielectrics involved. An almost perfect absorption up to 99.8% is demonstrated at resonance for all polarization states of light and for a very wide angular aperture. These properties originate from a magnetic Fabry-Perot mode that is confined in a dielectric spacer of λ/100 thickness by a metamaterial layer and a mirror. An extraordinary large funneling through nano-slits explains how light can be trapped in the structure. Simple scaling laws can be used as a recipe to design ultra-thin perfect absorbers whatever the materials and the desired resonance wavelength, making our design truly universal. PMID:27599634

  6. A universal design to realize a tunable perfect absorber from infrared to microwaves.

    PubMed

    Smaali, Rafik; Omeis, Fatima; Moreau, Antoine; Taliercio, Thierry; Centeno, Emmanuel

    2016-09-07

    We propose a design for an universal absorber, characterized by a resonance frequency that can be tuned from visible to microwave frequencies independently of the choice of the metal and the dielectrics involved. An almost perfect absorption up to 99.8% is demonstrated at resonance for all polarization states of light and for a very wide angular aperture. These properties originate from a magnetic Fabry-Perot mode that is confined in a dielectric spacer of λ/100 thickness by a metamaterial layer and a mirror. An extraordinary large funneling through nano-slits explains how light can be trapped in the structure. Simple scaling laws can be used as a recipe to design ultra-thin perfect absorbers whatever the materials and the desired resonance wavelength, making our design truly universal.

  7. A universal design to realize a tunable perfect absorber from infrared to microwaves

    PubMed Central

    Smaali, Rafik; Omeis, Fatima; Moreau, Antoine; Taliercio, Thierry; Centeno, Emmanuel

    2016-01-01

    We propose a design for an universal absorber, characterized by a resonance frequency that can be tuned from visible to microwave frequencies independently of the choice of the metal and the dielectrics involved. An almost perfect absorption up to 99.8% is demonstrated at resonance for all polarization states of light and for a very wide angular aperture. These properties originate from a magnetic Fabry-Perot mode that is confined in a dielectric spacer of λ/100 thickness by a metamaterial layer and a mirror. An extraordinary large funneling through nano-slits explains how light can be trapped in the structure. Simple scaling laws can be used as a recipe to design ultra-thin perfect absorbers whatever the materials and the desired resonance wavelength, making our design truly universal. PMID:27599634

  8. A universal design to realize a tunable perfect absorber from infrared to microwaves

    NASA Astrophysics Data System (ADS)

    Smaali, Rafik; Omeis, Fatima; Moreau, Antoine; Taliercio, Thierry; Centeno, Emmanuel

    2016-09-01

    We propose a design for an universal absorber, characterized by a resonance frequency that can be tuned from visible to microwave frequencies independently of the choice of the metal and the dielectrics involved. An almost perfect absorption up to 99.8% is demonstrated at resonance for all polarization states of light and for a very wide angular aperture. These properties originate from a magnetic Fabry-Perot mode that is confined in a dielectric spacer of λ/100 thickness by a metamaterial layer and a mirror. An extraordinary large funneling through nano-slits explains how light can be trapped in the structure. Simple scaling laws can be used as a recipe to design ultra-thin perfect absorbers whatever the materials and the desired resonance wavelength, making our design truly universal.

  9. Radiation characterization analysis of pushbroom longwave infrared imaging spectrometer

    NASA Astrophysics Data System (ADS)

    Shi, Rongbao; Chen, Yuheng; Zhou, Jiankang; Shen, Weiming

    2013-12-01

    Noise equivalent temperature difference (NETD) is the key parameter characterizing the detectivity of infrared systems. Our developed pushbroom longwave infrared imaging spectrometer works in a waveband between 8μm to 10.5 μm. Its temperature sensitivity property is not only affected by atmosphere attenuation, transmittance of the optical system and the characteristics of electric circuit, but also restricted by the self-radiation. The NETD accurate calculation formula is derived according to its definition. Radiation analysis model of a pushbroom image spectrometer is set up, and its self-radiation is analyzed and calculated at different temperatures, such as 300K, 150K and 120K. Based on the obtained accurate formula, the relationships between the NETD of imaging spectrometer and atmospheric attenuation, F-number, effective pixel area of detector, equivalent noise bandwidth and CCD detectivity are analyzed in detail, and self-radiation is particularly discussed. The work we have done is to provide the basis for parameters determination in spectrometer system.

  10. The interplay between assumed morphology and the direct radiative effect of light-absorbing organic aerosol

    NASA Astrophysics Data System (ADS)

    Saleh, Rawad; Adams, Peter J.; Donahue, Neil M.; Robinson, Allen L.

    2016-08-01

    Mie theory is widely employed in aerosol top-of-the-atmosphere direct radiative effect (DRE) calculations and to retrieve the absorptivity of light-absorbing organic aerosol (OA) from measurements. However, when OA is internally mixed with black carbon, it may exhibit complex morphologies whose optical behavior is imperfectly predicted by Mie theory, introducing bias in the retrieved absorptivities. We performed numerical experiments and global radiative transfer modeling (RTM) to investigate the effect of this bias on the calculated absorption and thus the DRE. We show that using true OA absorptivity, retrieved with a realistic representation of the complex morphology, leads to significant errors in DRE when the RTM employs the simplified Mie theory. On the other hand, when Mie theory is consistently applied in both OA absorptivity retrieval and the RTM, the errors largely cancel out, yielding accurate DRE. As long as global RTMs use Mie theory, they should implement parametrizations of light-absorbing OA derived from retrievals based on Mie theory.

  11. From Anti-greenhouse Effect of Solar Absorbers to Cooling Effect of Greenhouse Gases: A 1-D Radiative Convective Model Study

    NASA Astrophysics Data System (ADS)

    Shia, R.

    2012-12-01

    The haze layer in Titan's upper atmosphere absorbs 90% of the solar radiation, but is inefficient for trapping infrared radiation generated by the surface. Its existence partially compensates for the greenhouse warming and keeps the surface approximately 9°C cooler than would otherwise be expected from the greenhouse effect alone. This is the so called anti-greenhouse effect (McKay et al., 1991). This effect can be used to alleviate the warming caused by the increasing level of greenhouse gases in the Earth's atmosphere. A one-dimensional radiative convective model (Kasting et al., 2009 and references listed there) is used to investigate the anti-greenhouse effect in the Earth atmosphere. Increasing of solar absorbers, e.g. aerosols and ozone, in the stratosphere reduces the surface solar flux and cool the surface. However, the absorption of the solar flux also increases the temperature in the upper atmosphere, while reduces the temperature at the surface. Thus, the temperature profile of the atmosphere changes and the regions with positive vertical temperature gradient are expanded. According to Shia (2010) the radiative forcing of greenhouse gases is directly related to the vertical temperature gradient. Under the new temperature profile increases of greenhouse gases should have less warming effect. When the solar absorbers keep increasing, eventually most of the atmosphere has positive temperature gradient and increasing greenhouse gases would cool the surface (Shia, 2011). The doubling CO2 scenario in the Earth atmosphere is simulated for different levels of solar absorbers using the 1-D RC model. The model results show that if the solar absorber increases to a certain level that less than 50% solar flux reaching the surface, doubling CO2 cools the surface by about 2 C. This means if the snowball Earth is generated by solar absorbers in the stratosphere, increasing greenhouse gases would make it freeze even more (Shia, 2011). References: Kasting, J. et al

  12. Acoustic radiation force and torque on an absorbing compressible particle in an inviscid fluid.

    PubMed

    Silva, Glauber T

    2014-11-01

    Exact formulas of the acoustic radiation force and torque exerted by an arbitrary time-harmonic wave on an absorbing compressible particle that is suspended in an inviscid fluid are presented. It is considered that the particle diameter is much smaller than the incident wavelength, i.e., the so-called Rayleigh scattering limit. Moreover, the particle absorption assumed here is due to the attenuation of compressional waves only. Shear waves inside and outside the particle are neglected, since the inner and outer viscous boundary layer of the particle are supposed to be much smaller than the particle radius. The obtained radiation force formulas are used to establish the trapping conditions of a particle by a single-beam acoustical tweezer based on a spherically focused ultrasound transducer. In this case, it is shown that the particle absorption has a pivotal role in single-beam trapping at the transducer focal region. Furthermore, it is found that only the first-order Bessel vortex beam can generate the radiation torque on a small particle. In addition, numerical evaluation of the radiation force and torque exerted on a benzene and an olive oil droplet suspended in water are presented and discussed. PMID:25373943

  13. Absorbed photosynthetically active radiation of steppe vegetation and sun-view geometry effects on APAR estimates

    NASA Technical Reports Server (NTRS)

    Walter-Shea, E. A.; Blad, B. L.; Mesarch, M. A.; Hays, C. J.; Deering, D. W.; Eck, T. F.

    1992-01-01

    Instantaneous fractions of absorbed photosynthetically active radiation (APAR) were measured at the Streletskaya Steppe Reserve in conjunction with canopy bidirectional-reflected radiation measured at solar zenith angles ranging between 37 and 74 deg during the Kursk experiment (KUREX-91). APAR values were higher for KUREX-91 than those for the first ISLSCP field experiment (FIFE-89) and the amount of APAR of a canopy was a function of solar zenith angle, decreasing as solar zenith angle increased at the resrve. Differences in absorption are attributed to leaf area index (LAI) and leaf angle distribution and subsequently transmitted radiation interactions. LAIs were considerably higher at the reserve than those at the FIFE site. Leaf angle distributions of the reserve approach a uniform distribution while distributions at the FIFE site more closely approximate erectophile distributions. Reflected photosynthetically active radiation (PAR) components at KUREX-91 and FIFE-89 were similar in magnitude and in their response to solar zenith angle. Transmitted PAR increased with increasing solar zenith angle at KUREX-91 and decreased with increasing solar zenith angle at FIFE-89. Transmitted PAR at FIFE-89 was considerably larger than those at KUREX-91.

  14. Acoustic radiation force and torque on an absorbing compressible particle in an inviscid fluid.

    PubMed

    Silva, Glauber T

    2014-11-01

    Exact formulas of the acoustic radiation force and torque exerted by an arbitrary time-harmonic wave on an absorbing compressible particle that is suspended in an inviscid fluid are presented. It is considered that the particle diameter is much smaller than the incident wavelength, i.e., the so-called Rayleigh scattering limit. Moreover, the particle absorption assumed here is due to the attenuation of compressional waves only. Shear waves inside and outside the particle are neglected, since the inner and outer viscous boundary layer of the particle are supposed to be much smaller than the particle radius. The obtained radiation force formulas are used to establish the trapping conditions of a particle by a single-beam acoustical tweezer based on a spherically focused ultrasound transducer. In this case, it is shown that the particle absorption has a pivotal role in single-beam trapping at the transducer focal region. Furthermore, it is found that only the first-order Bessel vortex beam can generate the radiation torque on a small particle. In addition, numerical evaluation of the radiation force and torque exerted on a benzene and an olive oil droplet suspended in water are presented and discussed.

  15. Spatial and spectral distributions of thermal radiation emitted by a semi-infinite body and absorbed by a flat film

    SciTech Connect

    Blandre, Etienne Chapuis, Pierre-Olivier; Vaillon, Rodolphe; Francoeur, Mathieu

    2015-05-15

    We analyze the radiative power emitted by a semi-infinite medium and absorbed by a flat film located in its vicinity. In the near-field regime, if the film is thin enough, the surface waves at the rear interface of the film can contribute to the heat transfer. As a result, the absorbed power can be enhanced farther from the front surface. In the near-to-far field transition regime, temporal coherence of thermal radiation and the associated interferences can be used to shape the spectrum of the transferred radiative heat flux by selecting approriate geometrical parameters. These results highlight possibilities to control both the location where the radiative power is absorbed in the film and the spectral distribution, which are of paramount importance for applications such as near-field thermophotovoltaics.

  16. The TIROS-N high resolution infrared radiation sounder

    NASA Technical Reports Server (NTRS)

    Koenig, E. W.

    1979-01-01

    The high-resolution infrared radiation sounder (HIRS/2) was developed and flown on the Television and Infrared Observation Satellite, N Series (TIROS-N) as one means of obtaining atmospheric vertical profile information. The HIRS/2 receives visible and infrared spectrum radiation through a single telescope and selects 20 narrow spectral channels by means of a rotating filter wheel. A passive radiant cooler provides an operating temperature of 106.7K for the HgCdTe and InSb detectors while the visible detector operates at instrument frame temperature. Low noise amplifiers and digital processing provide 13 bit data for spacecraft data multiplexing and transmission. The qualities of system performance that determine sounding capability are the dynamic range of data collection, the noise equivalent radiance of the system, the registration of the air columns sampled in each channel, and the ability to upgrade the calibration of the instrument to maintain the performance standard throughout life. The basic performance of the instrument in test is described. Early orbital information from the TIROS-N launched on October 13, 1978 are given and some observations on system quality are made.

  17. Effect of UV-C radiation and vapor released from a water hyacinth root absorbent containing bergamot oil to control mold on storage of brown rice.

    PubMed

    Songsamoe, Sumethee; Matan, Narumol; Matan, Nirundorn

    2016-03-01

    The aims of this study were to develop absorbent material from a water hyacinth root containing bergamot oil and to improve its antifungal activity by using ultraviolet C (UV-C) against the growth of A. flavus on the brown rice. Process optimization was studied by the immersion of a water hyacinth root into a water and bergamot oil (300, 500 and 700 μl ml(-1)). The root (absorbent material) was dried at 50, 70, and 90 °C for 10 min. Then, ultraviolet C (UV-C) was used for enhancing the antifungal activity of bergamot oil for 10, 15, and 20 min. The shelf-life of the brown rice with the absorbent after incubation at 25 ° C with 100 % RH for 12 weeks was also investigated. A microscope and a Fourier transform infrared spectroscopy (FTIR) were used to find out possible mode of action. Results indicated that the absorbent material produced from the water hyacinth root containing bergamot oil at 500 μl ml(-1) in the water solution, dried at 70 ° C and UV for 15 min showed the highest antifungal activity in a vapor phase against A. flavus on the brown rice. A microscopy investigation confirmed that the water hyacinth root could absorb bergamot oil from an outside water solution into root cells. Limonene in vapor phase was shown to be a stronger inhibitor than essential oil after UV-C radiation and should be the key factor in boosting bergamot oil antifungal activity. A vapor phase of bergamot oil could be released and inhibit natural mold on the surface of the brown rice for up to 12 weeks; without the absorbent, mold covered the brown rice in only 4 weeks. PMID:27570269

  18. Verification of absorbed dose using diodes in cobalt-60 radiation therapy.

    PubMed

    Gadhi, Muhammad Asghar; Fatmi, Shahab; Chughtai, Gul M; Arshad, Muhammad; Shakil, Muhammad; Rahmani, Uzma Mahmood; Imran, Malik Younas; Buzdar, Saeed Ahmad

    2016-03-01

    The objective of this work was to enhance the quality and safety of dose delivery in the practice of radiation oncology. To achieve this goal, the absorbed dose verification program was initiated by using the diode in vivo dosimetry (IVD) system (for entrance and exit). This practice was implemented at BINO, Bahawalpur, Pakistan. Diodes were calibrated for making absorbed dose measurements. Various correction factors (SSD, dose non-linearity, field size, angle of incidence, and wedge) were determined for diode IVD system. The measurements were performed in phantom in order to validate the IVD procedure. One hundred and nineteen patients were monitored and 995 measurements were performed. For phantom, the percentage difference between measured and calculated dose for entrance setting remained within ±2% and for exit setting ±3%. For patient measurements, the percentage difference between measured and calculated dose remained within ±5% for entrance/open fields and ±7% for exit/wedge/oblique fields. One hundred and nineteen patients and 995 fields have been monitored during the period of 6 months. The analysis of all available measurements gave a mean percent deviation of ±1.19% and standard deviation of ±2.87%. Larger variations have been noticed in oblique, wedge and exit measurements. This investigation revealed that clinical dosimetry using diodes is simple, provides immediate results and is a useful quality assurance tool for dose delivery. It has enhanced the quality of radiation dose delivery and increased/improved the reliability of the radiation therapy practice in BINO. PMID:26753835

  19. Evaluating Direct Radiative Effects of Absorbing Aerosols on Atmospheric Dynamics with Aquaplanet and Regional Model Results

    NASA Astrophysics Data System (ADS)

    Can, Ö.; Tegen, I.; Quaas, J.

    2015-12-01

    Effects of absorbing aerosol on atmospheric dynamics are usually investigated with help of general circulation models or also regional models that represent the atmospheric system as realistic as possible. Reducing the complexity of models used to study the effects of absorbing aerosol on atmospheric dynamics helps to understand underlying mechanisms. In this study, by using ECHAM6 General Circulation Model (GCM) in an Aquaplanet setting and using simplified aerosol climatology, an initial idealization step has been taken. The analysis only considers direct radiative effects, furthering the reduction of complex model results. The simulations include cases including aerosol radiative forcing, no aerosol forcing, coarse mode aerosol forcing only (as approximation for mineral dust forcing) and forcing with increased aerosol absorption. The results showed that increased absorption affects cloud cover mainly in subtropics. Hadley circulation is found to be weakened in the increased absorption case. To compare the results of the idealized model with a more realistic model setting, the results of the regional model COSMO-MUSCAT that includes interactive mineral dust aerosol and considers the effects of dust radiative forcing are also analyzed. The regional model computes the atmospheric circulation for the year 2007 twice, including the feedback of dust and excluding the dust aerosol forcing. It is investigated to which extent the atmospheric response to the dust forcing agrees with the simplified Aquaplanet results. As expected, in the regional model mineral dust causes an increase in the temperature right above the dust layer while reducing the temperature close to the surface. In both models the presence of aerosol forcing leads to increased specific humidity, close to ITCZ. Notwithstanding the difference magnitudes, comparisons of the global aquaplanet and the regional model showed similar patterns. Further detailed comparisons will be presented.

  20. Mid- and far-infrared spectroscopy of ices: optical constants and integrated absorbances.

    PubMed

    Hudgins, D M; Sandford, S A; Allamandola, L J; Tielens, A G

    1993-06-01

    Laboratory spectra through the mid-infrared (4000 to 500 cm-1 [2.5-20 micrometers]) have been used to calculate the optical constants (n and k) and integrated absorption coefficients (A) for a variety of pure and mixed molecular ices of relevance to astrophysics. The ices studied were H2O, CH3OH, CO2, OCS, CH4, CO2 + CH4, CO2 + OCS, CO + CH4, CO + OCS, O2 + CH4, O2 + OCS, N2 + CH4, N2 + OCS, H2O + CH4, H2O + OCS, and H2O + CH3OH + CO + NH3. In addition, the measurements have been extended through the far-infrared (500 to 50 cm-1 [20-200 micrometers]) for the H2O, CH3OH, and H2O + CH3OH + CO + NH3 ices.

  1. Analysis of the radiative budget of Venus atmosphere based on infrared Net Exchange Rate formalism

    NASA Astrophysics Data System (ADS)

    Lebonnois, S.; Eymet, V.; Lee, C.; Vatant d'Ollone, J.

    2015-10-01

    The thick cloud cover present in the atmosphere of Venus between roughly 47 and 70 km of altitude plays a crucial role in the radiative balance of this system,by reflecting more than 75 % of the incoming solar flux back to space, absorbing half of the remaining flux, and being also optically thick over most of the infrared spectral range. The temperature profile of the atmosphere of Venus is characterized by a very hot troposphere from the surface (˜735 K) to roughly 60 km altitude, in the middle clouds. The strong greenhouse effect is provided by the 92 bars of CO2 that is the main constituent of the atmosphere and by the thick cloud layer.

  2. A Fast Infrared Radiative Transfer Model for Overlapping Clouds

    NASA Technical Reports Server (NTRS)

    Niu, Jianguo; Yang, Ping; Huang, Huang-Lung; Davies, James E.; Li, Jun; Baum, Bryan A.; Hu, Yong X.

    2006-01-01

    A fast infrared radiative transfer model (FIRTM2) appropriate for application to both single-layered and overlapping cloud situations is developed for simulating the outgoing infrared spectral radiance at the top of the atmosphere (TOA). In FIRTM2 a pre-computed library of cloud reflectance and transmittance values is employed to account for one or two cloud layers, whereas the background atmospheric optical thickness due to gaseous absorption can be computed from a clear-sky radiative transfer model. FIRTM2 is applicable to three atmospheric conditions: 1) clear-sky, 2) single-layered ice or water cloud, and 3) two simultaneous cloud layers in a column (e.g., ice cloud overlying water cloud). Moreover, FIRTM2 outputs the derivatives (i.e., Jacobians) of the TOA brightness temperature with respect to cloud optical thickness and effective particle size. Sensitivity analyses have been carried out to assess the performance of FIRTM2 for two spectral regions, namely the longwave (LW) band (587.3 - 1179.5/cm) and the short-to-medium wave (SMW) band (1180.1 - 2228.9/cm). The assessment is carried out in terms of brightness temperature differences (BTD) between FIRTM2 and the well-known discrete ordinates radiative transfer model (DISORT), henceforth referred to as BTD (F-D). The BTD (F-D) values for single-layered clouds are generally less than 0.8 K. For the case of two cloud layers (specifically ice cloud over water cloud), the BTD(F-D) values are also generally less than 0.8 K except for the SMW band for the case of a very high altitude (>15 km) cloud comprised of small ice particles. Note that for clear-sky atmospheres, FIRTM2 reduces to the clear-sky radiative transfer model that is incorporated into FIRTM2, and the errors in this case are essentially those of the clear-sky radiative transfer model.

  3. Determination of the absorbed dose and the average LET of space radiation in dependence on shielding conditions.

    PubMed

    Vana, N; Schoner, W; Noll, M; Fugger, M; Akatov, Y; Shurshakov, V

    1999-01-01

    The HTR method, developed for determination of absorbed dose and average LET of mixed radiation fields in space, was applied during several space missions on space station MIR, space shuttles and satellites. The method utilises the changes of peak height ratios in the glow curves in dependence on the linear energy transfer LET. Due to the small size of the dosemeters the evaluation of the variation of absorbed dose and average LET in dependence on the position of the dosemeters inside the space station is possible. The dose and LET distribution was determined during the experiment ADLET where dosemeters were exposed in two positions with different shielding conditions and during two following experiments (MIR-95, MIR-96) using six positions inside the space station. The results were compared with the shielding conditions of the positions. Calculations of the absorbed dose were carried out for comparison. Results have shown that the average LET increases with increasing absorbing thickness while the absorbed dose decreases.

  4. Influence of absorbing aerosols on the inference of solar surface radiation budget and cloud absorption

    SciTech Connect

    Li, Zhanqing

    1998-01-01

    This study addresses the impact of absorbing aerosols on the retrieval of the solar surface radiation budget (SSRB) and on the inference of cloud absorption using multiple global datasets. The data pertain to the radiation budgets at the top of the atmosphere (TOA), at the surface, and to precipitation and tropical biomass burning. Satellite-based SSRB data were derived from the Earth Radiation Budget Experiment and the International Satellite Cloud Climatology Program using different inversion algorithms. A manifestation of the aerosol effect emerges from a zonal comparison between satellite-based and surface-observed SSRB, which shows good agreement in most regions except over the tropical continents active in biomass burning. Another indication arises from the variation of the ratio of cloud radiative forcing at the TOA and at the surface, which was used in many recent studies addressing the cloud absorption problem. The author`s studies showed that the ratio is around unity under most circumstances except when there is heavy urban/industrial pollution or fires. These exceptions register discrepancy between observed and modeled SSRB. The discrepancy is found to increase with decreasing cloudiness, implying that it has more to do with the treatment of aerosols than clouds, although minor influences by other factors may also exist. The largest discrepancy is observed in the month of minimal cloud cover and maximal aerosol loading. The corresponding maximum monthly mean aerosol optical thickness is estimated to be around 1.0 by a parameterization developed in this study. After the effects of aerosols on SSRB are accounted for using biomass burning and precipitation data, disagreements no longer exist between the theory and observation with regard to the transfer of solar radiation. It should be pointed out that the tropical data employed in this study are limited to a small number of continental sites. 75 refs., 9 figs., 1 tab.

  5. Plasmonic materials based on ZnO films and their potential for developing broadband middle-infrared absorbers

    SciTech Connect

    Kesim, Yunus E. Battal, Enes; Okyay, Ali K.

    2014-07-15

    Noble metals such as gold and silver have been extensively used for plasmonic applications due to their ability to support plasmons, yet they suffer from high intrinsic losses. Alternative plasmonic materials that offer low loss and tunability are desired for a new generation of efficient and agile devices. In this paper, atomic layer deposition (ALD) grown ZnO is investigated as a candidate material for plasmonic applications. Optical constants of ZnO are investigated along with figures of merit pertaining to plasmonic waveguides. We show that ZnO can alleviate the trade-off between propagation length and mode confinement width owing to tunable dielectric properties. In order to demonstrate plasmonic resonances, we simulate a grating structure and computationally demonstrate an ultra-wide-band (4–15 μm) infrared absorber.

  6. Stratospheric aerosol properties and their effects on infrared radiation.

    NASA Technical Reports Server (NTRS)

    Remsberg, E. E.

    1973-01-01

    This paper presents a stratospheric aerosol model and infers its effects on terrestrial radiation. Composition of the aerosol is assumed to be concentrated sulfuric acid. An appropriate size distribution has been determined from available size distribution measurements of other investigators. Aerosols composed of concentrated sulfuric acid emit energy in the atmospheric window region of the infrared spectrum, 8-13 microns. Laboratory measurements of optical constant data obtained at room temperature are presented for 75 and 90% aqueous sulfuric acid. Calculations of an aerosol extinction coefficient are then performed by using the above data. Effects of changes in aerosol phase and temperature are discussed but not resolved.

  7. Radiation absorbed dose estimates for [1-carbon-11]-glucose in adults: The effects of hyperinsulinemia

    SciTech Connect

    Powers, W.J. |

    1996-10-01

    As preparation for studies of blood-brain glucose transport in diabetes mellitus, radiation absorbed dose estimates from intravenous administration of [1-{sup 11}C]-glucose for 24 internal organs, lens, blood and total body were calculated for three physiologic conditions: euinsulinemic euglycemia, hyperinsulinemic euglycemia and hyperinsulinemic hyperglycemia. Cumulated activities in blood, insulin-independent and insulin-dependent compartments were calculated from blood time-activity curves in normal human volunteers and macaques. Apportionment of cumulated activity to individual organs in insulin-dependent and insulin-independent compartments was based on previously published data. Absorbed doses were calculated with the computer program MIRDOSE 3 for the 70-kg adult phantom. S for blood was calculated separately. The heart wall, lungs and spleen were the organs receiving the highest dose. The effect of hyperinsulinemia was demonstrated by the increase in adsorbed dose to the muscle, heart and blood with a decrease to other internal organs. This effect was more pronounced during hyperinsulinemic hyperglycemia. Hyperinsulinemia produced a decrease in effective dose due to the decrease in cumulated activity in organs with specified weighting factors greater than 0.05. The effective dose per study for [1-{sup 11}C]-glucose is comparable to that reported for 2-deoxy-[2-{sup 18}F]-glucose. 43 refs., 1 fig., 4 tabs.

  8. Measurement-based estimates of direct radiative effects of absorbing aerosols above clouds

    NASA Astrophysics Data System (ADS)

    Feng, Nan; Christopher, Sundar A.

    2015-07-01

    The elevated layers of absorbing smoke aerosols from western African (e.g., Gabon and Congo) biomass burning activities have been frequently observed above low-level stratocumulus clouds off the African coast, which presents an excellent natural laboratory for studying the effects of aerosols above clouds (AAC) on regional energy balance in tropical and subtropical environments. Using spatially and temporally collocated Moderate Resolution Imaging Spectroradiometer, Ozone Monitoring Instrument (OMI), and Clouds and the Earth's Radiant Energy System data sets, the top-of-atmosphere shortwave aerosol direct shortwave radiative effects (ARE) of absorbing aerosols above low-level water clouds in the southeast Atlantic Ocean was examined in this study. The regional averaged instantaneous ARE has been estimated to be 36.7 ± 20.5 Wm-2 (regional mean ± standard deviation) along with a mean positive OMI Aerosol Index at 1.3 in August 2006 based on multisensors measurements. The highest magnitude of instantaneous ARE can even reach 138.2 Wm-2. We assess that the 660 nm cloud optical depth (COD) values of 8-12 is the critical value above (below) which aerosol absorption (scattering) effect dominates and further produces positive (negative) ARE values. The results further show that ARE values are more sensitive to aerosols above lower COD values than cases for higher COD values. This is among the first studies to provide quantitative estimates of shortwave ARE due to AAC events from an observational perspective.

  9. The influence of infrared radiation on short-term ultraviolet-radiation-induced injuries

    SciTech Connect

    Kaidbey, K.H.; Witkowski, T.A.; Kligman, A.M.

    1982-05-01

    Because heat has been reported to influence adversely short- and long-term ultraviolet (UV)-radiation-induced skin damage in animals, we investigated the short-term effects of infrared radiation on sunburn and on phototoxic reactions to topical methoxsalen and anthracene in human volunteers. Prior heating of the skin caused suppression of the phototoxic response to methoxsalen as evidenced by an increase in the threshold erythema dose. Heat administered either before or after exposure to UV radiation had no detectable influence on sunburn erythema or on phototoxic reactions provoked by anthracene.

  10. Infrared radiation from explosions in a spark-ignition engine

    NASA Technical Reports Server (NTRS)

    Marvin, Charles F , Jr; Caldwell, Frank R; Steele, Sydney

    1935-01-01

    This report presents the results of an investigation to determine the variations in intensity and spectral distribution of the radiant energy emitted by the flames during normal and knocking explosions in an engine. Radiation extending into the infrared was transmitted by a window of fluorite, placed either near the spark plug or over the detonation zone at opposite ends of the combustion chamber. Concave, surface-silvered mirrors focused the beam, first at the slit of a stroboscope which opened for about 2 degrees of crank angle at any desired point in the engine cycle, and then upon the target of a sensitive thermocouple for measuring radiation intensity. Spectral distribution of the radiant energy was determined by placing over the window, one at a time, a series of five filters selected with a view to identifying, as far as possible without the use of a spectrograph, the characteristic emissions of water vapor, carbon dioxide, and incandescent carbon.

  11. Growth of textured thin Au coatings on iron oxide nanoparticles with near infrared absorbance

    PubMed Central

    Ma, L L; Borwankar, A U; Willsey, B W; Yoon, K Y; Tam, J O; Sokolov, K V; Feldman, M D; Milner, T E; Johnston, K P

    2013-01-01

    A homologous series of Au-coated iron oxide nanoparticles, with hydrodynamic diameters smaller than 60 nm was synthesized with very low Auto-iron mass ratios as low as 0.15. The hydrodynamic diameter was determined by dynamic light scattering and the composition by atomic absorption spectroscopy and energy dispersive x-ray spectroscopy (EDS). Unusually low Au precursor supersaturation levels were utilized to nucleate and grow Au coatings on iron oxide relative to formation of pure Au nanoparticles. This approach produced unusually thin coatings, by lowering autocatalytic growth of Au on Au, as shown by transmission electron microscopy (TEM). Nearly all of the nanoparticles were attracted by a magnet indicating a minimal amount of pure Au particles The coatings were sufficiently thin to shift the surface plasmon resonance (SPR) to the near infrared (NIR), with large extinction coefficients., despite the small particle hydrodynamic diameters, observed from dynamic light scattering to be less than 60 nm. PMID:23238021

  12. Note: three wavelengths near-infrared spectroscopy system for compensating the light absorbance by water.

    PubMed

    Bhutta, M Raheel; Hong, Keum-Shik; Kim, Beop-Min; Hong, Melissa Jiyoun; Kim, Yun-Hee; Lee, Se-Ho

    2014-02-01

    Given that approximately 80% of blood is water, we develop a wireless functional near-infrared spectroscopy system that detects not only the concentration changes of oxy- and deoxy-hemoglobin (HbO and HbR) during mental activity but also that of water (H2O). Additionally, it implements a water-absorption correction algorithm that improves the HbO and HbR signal strengths during an arithmetic task. The system comprises a microcontroller, an optical probe, tri-wavelength light emitting diodes, photodiodes, a WiFi communication module, and a battery. System functionality was tested by means of arithmetic-task experiments performed by healthy male subjects. PMID:24593411

  13. SUPERCRITICAL SOLVOTHERMAL SYNTHESIS AND NEAR-INFRARED ABSORBING PROPERTIES OF CsxWO3

    NASA Astrophysics Data System (ADS)

    Guo, Chongshen; Yin, Shu; Huang, Yunfang; Dong, Qiang; Li, Huihui; Sato, Tsugio

    2012-06-01

    CsxWO3 nanoparticles in the range of 20-50 nm have been successfully synthesized by the supercritical solvothermal approach, where after dissolving WCl6 and CsOH in a mixed solution of water, ethanol and oleic acid, the solution was heated at 300°C. The products were characterized by X-ray diffraction, TEM, HR-TEM, EDS, laser particle size analysis and thermographic measurements. CsxWO3 nanoparticles showed the high transparency in the visible region, excellent shielding performance of the near-infrared light and limited reflectance of light in the range of 200-2700 nm, indicating the strong absorption of NIR light on the nanosized CsxWO3. CsxWO3 nanoparticles also exhibited quick conversion of photo-energy to local heat.

  14. Transparent Organic Photodetector using a Near-Infrared Absorbing Cyanine Dye

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Jenatsch, Sandra; de Jonghe, Jelissa; Nüesch, Frank; Steim, Roland; Véron, Anna C.; Hany, Roland

    2015-03-01

    Organic photodetectors are interesting for low cost, large area optical sensing applications. Combining organic semiconductors with discrete absorption bands outside the visible wavelength range with transparent and conductive electrodes allows for the fabrication of visibly transparent photodetectors. Visibly transparent photodetectors can have far reaching impact in a number of areas including smart displays, window-integrated electronic circuits and sensors. Here, we demonstrate a near-infrared sensitive, visibly transparent organic photodetector with a very high average visible transmittance of 68.9%. The transmitted light of the photodetector under solar irradiation exhibits excellent transparency colour perception and rendering capabilities. At a wavelength of 850 nm and at -1 V bias, the photoconversion efficiency is 17% and the specific detectivity is 1012 Jones. Large area photodetectors with an area of 1.6 cm2 are demonstrated.

  15. Transparent organic photodetector using a near-infrared absorbing cyanine dye.

    PubMed

    Zhang, Hui; Jenatsch, Sandra; De Jonghe, Jelissa; Nüesch, Frank; Steim, Roland; Véron, Anna C; Hany, Roland

    2015-03-24

    Organic photodetectors are interesting for low cost, large area optical sensing applications. Combining organic semiconductors with discrete absorption bands outside the visible wavelength range with transparent and conductive electrodes allows for the fabrication of visibly transparent photodetectors. Visibly transparent photodetectors can have far reaching impact in a number of areas including smart displays, window-integrated electronic circuits and sensors. Here, we demonstrate a near-infrared sensitive, visibly transparent organic photodetector with a very high average visible transmittance of 68.9%. The transmitted light of the photodetector under solar irradiation exhibits excellent transparency colour perception and rendering capabilities. At a wavelength of 850 nm and at -1 V bias, the photoconversion efficiency is 17% and the specific detectivity is 10(12) Jones. Large area photodetectors with an area of 1.6 cm(2) are demonstrated.

  16. Note: Three wavelengths near-infrared spectroscopy system for compensating the light absorbance by water

    NASA Astrophysics Data System (ADS)

    Bhutta, M. Raheel; Hong, Keum-Shik; Kim, Beop-Min; Hong, Melissa Jiyoun; Kim, Yun-Hee; Lee, Se-Ho

    2014-02-01

    Given that approximately 80% of blood is water, we develop a wireless functional near-infrared spectroscopy system that detects not only the concentration changes of oxy- and deoxy-hemoglobin (HbO and HbR) during mental activity but also that of water (H2O). Additionally, it implements a water-absorption correction algorithm that improves the HbO and HbR signal strengths during an arithmetic task. The system comprises a microcontroller, an optical probe, tri-wavelength light emitting diodes, photodiodes, a WiFi communication module, and a battery. System functionality was tested by means of arithmetic-task experiments performed by healthy male subjects.

  17. Tunable ultrasonic phononic crystal controlled by infrared radiation

    SciTech Connect

    Walker, Ezekiel; Neogi, Arup E-mail: arup@unt.edu; Reyes, Delfino; Rojas, Miguel Mayorga; Krokhin, Arkadii; Wang, Zhiming E-mail: arup@unt.edu

    2014-10-06

    A tunable phononic crystal based ultrasonic filter was designed by stimulating the phase of the polymeric material embedded in a periodic structure using infrared radiation. The acoustic filter can be tuned remotely using thermal stimulation induced by the infrared radiation. The filter is composed of steel cylinder scatterers arranged periodically in a background of bulk poly (N-isopropylacrylamide) polymer hydrogel. The lattice structure creates forbidden bands for certain sets of mechanical waves that cause it to behave as an ultrasonic filter. Since the bandstructure is determined by not only the arrangement of the scatterers but also the physical properties of the materials composing the scatterers and background, modulating either the arrangement or physical properties will alter the effect of the crystal on propagating mechanical waves. Here, the physical properties of the filter are varied by inducing changes in the polymer hydrogel using an electromagnetic thermal stimulus. With particular focus on the k{sub 00}-wave, the transmission of ultrasonic wave changes by as much as 20 dBm, and band widths by 22% for select bands.

  18. Tunable ultrasonic phononic crystal controlled by infrared radiation

    NASA Astrophysics Data System (ADS)

    Walker, Ezekiel; Reyes, Delfino; Rojas, Miguel Mayorga; Krokhin, Arkadii; Wang, Zhiming; Neogi, Arup

    2014-10-01

    A tunable phononic crystal based ultrasonic filter was designed by stimulating the phase of the polymeric material embedded in a periodic structure using infrared radiation. The acoustic filter can be tuned remotely using thermal stimulation induced by the infrared radiation. The filter is composed of steel cylinder scatterers arranged periodically in a background of bulk poly (N-isopropylacrylamide) polymer hydrogel. The lattice structure creates forbidden bands for certain sets of mechanical waves that cause it to behave as an ultrasonic filter. Since the bandstructure is determined by not only the arrangement of the scatterers but also the physical properties of the materials composing the scatterers and background, modulating either the arrangement or physical properties will alter the effect of the crystal on propagating mechanical waves. Here, the physical properties of the filter are varied by inducing changes in the polymer hydrogel using an electromagnetic thermal stimulus. With particular focus on the k00-wave, the transmission of ultrasonic wave changes by as much as 20 dBm, and band widths by 22% for select bands.

  19. General Strategy for the Bioorthogonal Incorporation of Strongly Absorbing, Solvation-Sensitive Infrared Probes into Proteins

    PubMed Central

    2015-01-01

    A high-sensitivity metal-carbonyl-based IR probe is described that can be incorporated into proteins or other biomolecules in very high yield via Click chemistry. A two-step strategy is demonstrated. First, a methionine auxotroph is used to incorporate the unnatural amino acid azidohomoalanine at high levels. Second, a tricarbonyl (η5-cyclopentadienyl) rhenium(I) probe modified with an alkynyl linkage is coupled via the Click reaction. We demonstrate these steps using the C-terminal domain of the ribosomal protein L9 as a model system. An overall incorporation level of 92% was obtained at residue 109, which is a surface-exposed residue. Incorporation of the probe into a surface site is shown not to perturb the stability or structure of the target protein. Metal carbonyls are known to be sensitive to solvation and protein electrostatics through vibrational lifetimes and frequency shifts. We report that the frequencies and lifetimes of this probe also depend on the isotopic composition of the solvent. Comparison of the lifetimes measured in H2O versus D2O provides a probe of solvent accessibility. The metal carbonyl probe reported here provides an easy and robust method to label very large proteins with an amino-acid-specific tag that is both environmentally sensitive and a very strong absorber. PMID:24749542

  20. Origin of the low frequency radiation emitted by radiative polaritons excited by infrared radiation in planar La2O3 films.

    PubMed

    Vincent-Johnson, Anita J; Schwab, Yosyp; Mann, Harkirat S; Francoeur, Mathieu; Hammonds, James S; Scarel, Giovanna

    2013-01-23

    Upon excitation in thin oxide films by infrared radiation, radiative polaritons are formed with complex angular frequency ω, according to the theory of Kliewer and Fuchs (1966 Phys. Rev. 150 573). We show that radiative polaritons leak radiation with frequency ω(i) to the space surrounding the oxide film. The frequency ω(i) is the imaginary part of ω. The effects of the presence of the radiation leaked out at frequency ω(i) are observed experimentally and numerically in the infrared spectra of La(2)O(3) films on silicon upon excitation by infrared radiation of the 0TH type radiative polariton. The frequency ω(i) is found in the microwave to far infrared region, and depends on the oxide film chemistry and thickness. The presented results might aid in the interpretation of fine structures in infrared and, possibly, optical spectra, and suggest the study of other similar potential sources of electromagnetic radiation in different physical scenarios.

  1. An unexpectedly branched biosynthetic pathway for bacteriochlorophyll b capable of absorbing near-infrared light

    PubMed Central

    Tsukatani, Yusuke; Yamamoto, Haruki; Harada, Jiro; Yoshitomi, Taichi; Nomata, Jiro; Kasahara, Masahiro; Mizoguchi, Tadashi; Fujita, Yuichi; Tamiaki, Hitoshi

    2013-01-01

    Chlorophyllous pigments are essential for photosynthesis. Bacteriochlorophyll (BChl) b has the characteristic C8-ethylidene group and therefore is the sole naturally occurring pigment having an absorption maximum at near-infrared light wavelength. Here we report that chlorophyllide a oxidoreductase (COR), a nitrogenase-like enzyme, showed distinct substrate recognition and catalytic reaction between BChl a- and b-producing proteobacteria. COR from BChl b-producing Blastochloris viridis synthesized the C8-ethylidene group from 8-vinyl-chlorophyllide a. In contrast, despite the highly conserved primary structures, COR from BChl a-producing Rhodobacter capsulatus catalyzes the C8-vinyl reduction as well as the previously known reaction of the C7 = C8 double bond reduction on 8-vinyl-chlorophyllide a. The present data indicate that the plasticity of the nitrogenase-like enzyme caused the branched pathways of BChls a and b biosynthesis, ultimately leading to ecologically different niches of BChl a- and b-based photosynthesis differentiated by more than 150 nm wavelength. PMID:23386973

  2. The distribution of sulfur dioxide and other infrared absorbers on the surface of Io

    USGS Publications Warehouse

    Carlson, R.W.; Smythe, W.D.; Lopes-Gautier, R. M. C.; Davies, A.G.; Kamp, L.W.; Mosher, J.A.; Soderblom, L.A.; Leader, F.E.; Mehlman, R.; Clark, R.N.; Fanale, F.P.

    1997-01-01

    The Galileo Near Infrared Mapping Spectrometer was used to investigate the distribution and properties of sulfur dioxide over the surface of Io, and qualitative results for the anti-Jove hemisphere are presented here. SO2, existing as a frost, is found almost everywhere, but with spatially variable concentration. The exceptions are volcanic hot spots, where high surface temperatures promote rapid vaporization and can produce SO2-free areas. The pervasive frost, if fully covering the cold surface, has characteristic grain sizes of 30 to 100 Urn, or greater. Regions of greater sulfur dioxide concentrations are found. The equatorial Colchis Regio area exhibits extensive snowfields with large particles (250 to 500 ??m diameter, or greater) beneath smaller particles. A weak feature at 3.15 ??m is observed and is perhaps due to hydroxides, hydrates, or water. A broad absorption in the 1 ??m region, which could be caused by iron-containing minerals, shows a concentration in Io'S southern polar region, with an absence in the Pele plume deposition ring. Copyright 1997 by the American Geophysical Union.

  3. Use of narrow-band spectra to estimate the fraction of absorbed photosynthetically active radiation

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G.; Huemmrich, Karl F.; Goward, Samuel N.

    1990-01-01

    A novel approach is proposed for using high-spectral resolution imagers to estimate the fraction of photosynthetically active radiation adsorbed, f(apar), by vegetated land surfaces. In comparison to approaches using broad-band vegetation indices, the proposed method appears to be relatively insensitive to the reflectance of nonphotosynthetically active material beneath the canopy, such as leaf litter or soil. The method is based on a relationship between the second derivative of the reflectance vs wavelength function for terrestrial vegetation and f(apar). The relationship can be defined by the second derivatives in either of two windows, one in the visible region centered at 0.69 micron, another in the near-infrared region centered at 0.74 micron.

  4. Estimating the Direct Radiative Effect of Absorbing Aerosols Overlying Marine Boundary Layer Clouds in the Southeast Atlantic Using MODIS and CALIOP

    NASA Technical Reports Server (NTRS)

    Meyer, Kerry; Platnick, Steven; Oreopoulos, Lazaros; Lee, Dongmin

    2013-01-01

    Absorbing aerosols such as smoke strongly absorb solar radiation, particularly at ultraviolet and visible/near-infrared (VIS/NIR) wavelengths, and their presence above clouds can have considerable implications. It has been previously shown that they have a positive (i.e., warming) direct aerosol radiative effect (DARE) when overlying bright clouds. Additionally, they can cause biased passive instrument satellite retrievals in techniques that rely on VIS/NIR wavelengths for inferring the cloud optical thickness (COT) and effective radius (re) of underlying clouds, which can in turn yield biased above-cloud DARE estimates. Here we investigate Moderate Resolution Imaging Spectroradiometer (MODIS) cloud optical property retrieval biases due to overlying absorbing aerosols observed by Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and examine the impact of these biases on above-cloud DARE estimates. The investigation focuses on a region in the southeast Atlantic Ocean during August and September (2006-2011), where smoke from biomass burning in southern Africa overlies persistent marine boundary layer stratocumulus clouds. Adjusting for above-cloud aerosol attenuation yields increases in the regional mean liquid COT (averaged over all ocean-only liquid clouds) by roughly 6%; mean re increases by roughly 2.6%, almost exclusively due to the COT adjustment in the non-orthogonal retrieval space. It is found that these two biases lead to an underestimate of DARE. For liquid cloud Aqua MODIS pixels with CALIOP-observed above-cloud smoke, the regional mean above-cloud radiative forcing efficiency (DARE per unit aerosol optical depth (AOD)) at time of observation (near local noon for Aqua overpass) increases from 50.9Wm(sup-2)AOD(sup-1) to 65.1Wm(sup-2)AOD(sup -1) when using bias-adjusted instead of nonadjusted MODIS cloud retrievals.

  5. Principal component analysis and radiative transfer modelling of Spitzer Infrared Spectrograph spectra of ultraluminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Hurley, P. D.; Oliver, S.; Farrah, D.; Wang, L.; Efstathiou, A.

    2012-08-01

    The mid-infrared spectra of ultraluminous infrared galaxies (ULIRGs) contain a variety of spectral features that can be used as diagnostics to characterize the spectra. However, such diagnostics are biased by our prior prejudices on the origin of the features. Moreover, by using only part of the spectrum they do not utilize the full information content of the spectra. Blind statistical techniques such as principal component analysis (PCA) consider the whole spectrum, find correlated features and separate them out into distinct components. We further investigate the principal components (PCs) of ULIRGs derived in Wang et al. We quantitatively show that five PCs are optimal for describing the Infrared Spectrograph spectra. These five components (PC1-PC5) and the mean spectrum provide a template basis set that reproduces spectra of all z < 0.35 ULIRGs within the noise. For comparison, the spectra are also modelled with a combination of radiative transfer models of both starbursts and the dusty torus surrounding active galactic nuclei (AGN). The five PCs typically provide better fits than the models. We argue that the radiative transfer models require a colder dust component and have difficulty in modelling strong polycyclic aromatic hydrocarbon features. Aided by the models we also interpret the physical processes that the PCs represent. The third PC is shown to indicate the nature of the dominant power source, while PC1 is related to the inclination of the AGN torus. Finally, we use the five PCs to define a new classification scheme using 5D Gaussian mixture modelling and trained on widely used optical classifications. The five PCs, average spectra for the four classifications and the code to classify objects are made available at: .

  6. Effect of aerosol concentration and absorbing aerosol on the radiation fog life cycle

    NASA Astrophysics Data System (ADS)

    Maalick, Z.; Kühn, T.; Korhonen, H.; Kokkola, H.; Laaksonen, A.; Romakkaniemi, S.

    2016-05-01

    Analogous to cloud formation, the formation and life cycle of fogs is largely influenced by aerosol particles. The objective of this work is to analyze how changes in aerosol properties affect the fog life cycle, with special emphasis on how droplet concentrations change with cloud condensation nuclei (CCN) concentrations and on the effect that absorbing black carbon (BC) particles have on fog dissipation. For our simulation case study, we chose a typical fall time radiation fog at mid-latitudes (45° north) in fairly highly polluted conditions. Our results show that CCN concentrations have a strong influence on the fog lifetime. This is because the immediate effect of CCN on cloud droplet number concentrations (CDNC) is enhanced through two positive feedback loops: (1) Higher CDNC leads to more radiative cooling at the fog top, which leads to even stronger activation and (2) if CDNC is higher, the average droplet size is smaller, which slows down droplet removal through sedimentation. The effect that radiation fogs have on solar surface irradiation is large - the daily mean can change by 50% if CCN concentrations are doubled or halved (considering a reference CCN mixing ratio of 800 #/mg). With the same changes in CCN, the total fog lifetime increases 160 min or decreases 65 min, respectively. Although BC has a noticeable effect on fog height and dissipation time, its relative effect compared to CCN is small, even if BC concentrations are high. The fog formation is very sensitive to initial meteorological conditions which may be altered considerably if fog was present the previous day. This effect was neglected here, and future simulations, which span several days, may thus be a valuable extension of this study.

  7. Absorbing Aerosols Above Cloud: Detection, Quantitative Retrieval, and Radiative Forcing from Satellite-based Passive Sensors

    NASA Astrophysics Data System (ADS)

    Jethva, H.; Torres, O.; Remer, L. A.; Bhartia, P. K.

    2012-12-01

    Light absorbing particles such as carbonaceous aerosols generated from biomass burning activities and windblown dust particles can exert a net warming effect on climate; the strength of which depends on the absorption capacity of the particles and brightness of the underlying reflecting background. When advected over low-level bright clouds, these aerosols absorb the cloud reflected radiation from ultra-violet (UV) to shortwave-IR (SWIR) and makes cloud scene darker-a phenomenon commonly known as "cloud darkening". The apparent "darkening" effect can be seen by eyes in satellite images as well as quantitatively in the spectral reflectance measurements made by space borne sensors over regions where light absorbing carbonaceous and dust aerosols overlay low-level cloud decks. Theoretical radiative transfer simulations support the observational evidence, and further reveal that the strength of the cloud darkening and its spectral signature (or color ratio) between measurements at two wavelengths are a bi-function of aerosol and cloud optical thickness (AOT and COT); both are measures of the total amount of light extinction caused by aerosols and cloud, respectively. Here, we developed a retrieval technique, named as the "color ratio method" that uses the satellite measurements at two channels, one at shorter wavelength in the visible and one at longer wavelength in the shortwave-IR for the simultaneous retrieval of AOT and COT. The present technique requires assumptions on the aerosol single-scattering albedo and aerosol-cloud separation which are supplemented by the Aerosol Robotic Network (AERONET) and space borne CALIOP lidar measurements. The retrieval technique has been tested making use of the near-UV and visible reflectance observations made by the Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) for distinct above-cloud smoke and dust aerosol events observed seasonally over the southeast and tropical Atlantic Ocean

  8. Biological Effects of Sunlight, Ultraviolet Radiation, Visible Light, Infrared Radiation and Vitamin D for Health.

    PubMed

    Holick, Michael F

    2016-03-01

    Humans evolved in sunlight and had depended on sunlight for its life giving properties that was appreciated by our early ancestors. However, for more than 40 years the lay press and various medical and dermatology associations have denounced sun exposure because of its association with increased risk for skin cancer. The goal of this review is to put into perspective the many health benefits that have been associated with exposure to sunlight, ultraviolet A (UVA) ultraviolet B (UVB), visible and infrared radiation.

  9. High near-infrared absorbing Cu5FeS4 nanoparticles for dual-modal imaging and photothermal therapy

    NASA Astrophysics Data System (ADS)

    Zhao, Qi; Yi, Xuan; Li, Meifang; Zhong, Xiaoyan; Shi, Quanliang; Yang, Kai

    2016-07-01

    Multifunctional nanomaterials have shown excellent and promising properties for cancer diagnosis and treatment. Herein, we have developed iron doped copper sulfide (Cu5FeS4) nanoparticles with a non-covalent polyethylene glycol (PEG) coating (Cu5FeS4-PEG) for tumor dual-modal imaging and photothermal therapy (PTT). The obtained Cu5FeS4-PEG nanoparticles with high near-infrared absorbance could be used for phototoacoustic (PA) imaging and PTT, whereas Fe3+ doping offer the nanoparticles the additional property for magnetic resonance (MR) imaging. As shown by PA imaging, Cu5FeS4-PEG exhibit a high tumor uptake (~10% ID g-1) after intravenous injection. In vitro and in vivo cancer treatment further confirm that Cu5FeS4-PEG could act as a novel therapeutic agent for PTT of cancer cells. Our study further promotes the potential applications of multifunctional nanomaterials in a range of tumor diagnoses and treatments.Multifunctional nanomaterials have shown excellent and promising properties for cancer diagnosis and treatment. Herein, we have developed iron doped copper sulfide (Cu5FeS4) nanoparticles with a non-covalent polyethylene glycol (PEG) coating (Cu5FeS4-PEG) for tumor dual-modal imaging and photothermal therapy (PTT). The obtained Cu5FeS4-PEG nanoparticles with high near-infrared absorbance could be used for phototoacoustic (PA) imaging and PTT, whereas Fe3+ doping offer the nanoparticles the additional property for magnetic resonance (MR) imaging. As shown by PA imaging, Cu5FeS4-PEG exhibit a high tumor uptake (~10% ID g-1) after intravenous injection. In vitro and in vivo cancer treatment further confirm that Cu5FeS4-PEG could act as a novel therapeutic agent for PTT of cancer cells. Our study further promotes the potential applications of multifunctional nanomaterials in a range of tumor diagnoses and treatments. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr04444a

  10. Far Infrared Spectrometry of the Cosmic Background Radiation

    DOE R&D Accomplishments Database

    Mather, J. C.

    1974-01-01

    I describe two experiments to measure the cosmic background radiation near 1 mm wavelength. The first was a ground-based search for spectral lines, made with a Fabry-Perot interferometer and an InSb detector. The second is a measurement of the spectrum from 3 to 18 cm{sup -1}, made with a balloon-borne Fourier transform spectrometer. It is a polarizing Michelson interferometer, cooled in liquid helium, and operated with a germanium bolometer. I give the theory of operation, construction details, and experimental results. The first experiment was successfully completed but the second suffered equipment malfunction on its first flight. I describe the theory of Fourier transformations and give a new understanding of convolutional phase correction computations. I discuss for infrared bolometer calibration procedures, and tabulate test results on nine detectors. I describe methods of improving bolometer sensitivity with immersion optics and with conductive film blackening.

  11. Algorithmic vs. finite difference Jacobians for infrared atmospheric radiative transfer

    NASA Astrophysics Data System (ADS)

    Schreier, Franz; Gimeno García, Sebastián; Vasquez, Mayte; Xu, Jian

    2015-10-01

    Jacobians, i.e. partial derivatives of the radiance and transmission spectrum with respect to the atmospheric state parameters to be retrieved from remote sensing observations, are important for the iterative solution of the nonlinear inverse problem. Finite difference Jacobians are easy to implement, but computationally expensive and possibly of dubious quality; on the other hand, analytical Jacobians are accurate and efficient, but the implementation can be quite demanding. GARLIC, our "Generic Atmospheric Radiation Line-by-line Infrared Code", utilizes algorithmic differentiation (AD) techniques to implement derivatives w.r.t. atmospheric temperature and molecular concentrations. In this paper, we describe our approach for differentiation of the high resolution infrared and microwave spectra and provide an in-depth assessment of finite difference approximations using "exact" AD Jacobians as a reference. The results indicate that the "standard" two-point finite differences with 1 K and 1% perturbation for temperature and volume mixing ratio, respectively, can exhibit substantial errors, and central differences are significantly better. However, these deviations do not transfer into the truncated singular value decomposition solution of a least squares problem. Nevertheless, AD Jacobians are clearly recommended because of the superior speed and accuracy.

  12. Secure thermal infrared communications using engineered blackbody radiation

    PubMed Central

    Liang, Xiaoxin; Hu, Fangjing; Yan, Yuepeng; Lucyszyn, Stepan

    2014-01-01

    The thermal (emitted) infrared frequency bands, from 20–40 THz and 60–100 THz, are best known for applications in thermography. This underused and unregulated part of the spectral range offers opportunities for the development of secure communications. The ‘THz Torch' concept was recently presented by the authors. This technology fundamentally exploits engineered blackbody radiation, by partitioning thermally-generated spectral noise power into pre-defined frequency channels; the energy in each channel is then independently pulsed modulated and multiplexing schemes are introduced to create a robust form of short-range secure communications in the far/mid infrared. To date, octave bandwidth (25–50 THz) single-channel links have been demonstrated with 380 bps speeds. Multi-channel ‘THz Torch' frequency division multiplexing (FDM) and frequency-hopping spread-spectrum (FHSS) schemes have been proposed, but only a slow 40 bps FDM scheme has been demonstrated experimentally. Here, we report a much faster 1,280 bps FDM implementation. In addition, an experimental proof-of-concept FHSS scheme is demonstrated for the first time, having a 320 bps data rate. With both 4-channel multiplexing schemes, measured bit error rates (BERs) of < 10−6 are achieved over a distance of 2.5 cm. Our approach represents a new paradigm in the way niche secure communications can be established over short links. PMID:24912871

  13. Secure thermal infrared communications using engineered blackbody radiation

    NASA Astrophysics Data System (ADS)

    Liang, Xiaoxin; Hu, Fangjing; Yan, Yuepeng; Lucyszyn, Stepan

    2014-06-01

    The thermal (emitted) infrared frequency bands, from 20-40 THz and 60-100 THz, are best known for applications in thermography. This underused and unregulated part of the spectral range offers opportunities for the development of secure communications. The `THz Torch' concept was recently presented by the authors. This technology fundamentally exploits engineered blackbody radiation, by partitioning thermally-generated spectral noise power into pre-defined frequency channels; the energy in each channel is then independently pulsed modulated and multiplexing schemes are introduced to create a robust form of short-range secure communications in the far/mid infrared. To date, octave bandwidth (25-50 THz) single-channel links have been demonstrated with 380 bps speeds. Multi-channel `THz Torch' frequency division multiplexing (FDM) and frequency-hopping spread-spectrum (FHSS) schemes have been proposed, but only a slow 40 bps FDM scheme has been demonstrated experimentally. Here, we report a much faster 1,280 bps FDM implementation. In addition, an experimental proof-of-concept FHSS scheme is demonstrated for the first time, having a 320 bps data rate. With both 4-channel multiplexing schemes, measured bit error rates (BERs) of < 10-6 are achieved over a distance of 2.5 cm. Our approach represents a new paradigm in the way niche secure communications can be established over short links.

  14. Secure thermal infrared communications using engineered blackbody radiation.

    PubMed

    Liang, Xiaoxin; Hu, Fangjing; Yan, Yuepeng; Lucyszyn, Stepan

    2014-01-01

    The thermal (emitted) infrared frequency bands, from 20-40 THz and 60-100 THz, are best known for applications in thermography. This underused and unregulated part of the spectral range offers opportunities for the development of secure communications. The 'THz Torch' concept was recently presented by the authors. This technology fundamentally exploits engineered blackbody radiation, by partitioning thermally-generated spectral noise power into pre-defined frequency channels; the energy in each channel is then independently pulsed modulated and multiplexing schemes are introduced to create a robust form of short-range secure communications in the far/mid infrared. To date, octave bandwidth (25-50 THz) single-channel links have been demonstrated with 380 bps speeds. Multi-channel 'THz Torch' frequency division multiplexing (FDM) and frequency-hopping spread-spectrum (FHSS) schemes have been proposed, but only a slow 40 bps FDM scheme has been demonstrated experimentally. Here, we report a much faster 1,280 bps FDM implementation. In addition, an experimental proof-of-concept FHSS scheme is demonstrated for the first time, having a 320 bps data rate. With both 4-channel multiplexing schemes, measured bit error rates (BERs) of < 10(-6) are achieved over a distance of 2.5 cm. Our approach represents a new paradigm in the way niche secure communications can be established over short links. PMID:24912871

  15. Effects of flameless catalytic infrared radiation on Sitophilus oryzae (L.) life stages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory bench top flameless catalytic infrared emitter was evaluated against all life stages of the rice weevil, Sitophilus oryzae (L.), an insect species associated with stored wheat. The infrared radiation emitted was in the 3 to 7 µm range. A non-contact infrared thermometer measured grain t...

  16. Estimation of the absorbed dose in radiation-processed food. 4. EPR measurements on eggshell

    SciTech Connect

    Desrosiers, M.F.; Le, F.G. ); Harewood, P.M.; Josephson, E.S. ); Montesalvo, M. )

    1993-09-01

    Fresh whole eggs treated with ionizing radiation for Salmonellae control testing. The eggshell was then removed and examined by electron paramagnetic resonance (EPR) spectroscopy to determine if EPR could be used to (1) distinguish irradiated from unirradiated eggs and (2) assess the absorbed dose. No EPR signals were detected in unirradiated eggs, while strong signals were measurable for more than 200 days after irradiation. Although a number of EPR signals were measured, the most intense resonance (g = 2.0019) was used for dosimetry throughout the study. This signal was observed to increase linearly with dose (up to [approximately]6 kGy), which decayed [approximately]20% within the first 5 days after irradiation and remained relatively constant thereafter. The standard added-dose method was used to assess, retrospectively, the dose to eggs processed at 0.2, 0.7, and 1.4 kGy. Relatively good results were obtained when measurement was made on the day the shell was reirradiated; with this procedure estimates were better for shell processed at the lower doses.

  17. High near-infrared absorbing Cu5FeS4 nanoparticles for dual-modal imaging and photothermal therapy.

    PubMed

    Zhao, Qi; Yi, Xuan; Li, Meifang; Zhong, Xiaoyan; Shi, Quanliang; Yang, Kai

    2016-07-21

    Multifunctional nanomaterials have shown excellent and promising properties for cancer diagnosis and treatment. Herein, we have developed iron doped copper sulfide (Cu5FeS4) nanoparticles with a non-covalent polyethylene glycol (PEG) coating (Cu5FeS4-PEG) for tumor dual-modal imaging and photothermal therapy (PTT). The obtained Cu5FeS4-PEG nanoparticles with high near-infrared absorbance could be used for phototoacoustic (PA) imaging and PTT, whereas Fe(3+) doping offer the nanoparticles the additional property for magnetic resonance (MR) imaging. As shown by PA imaging, Cu5FeS4-PEG exhibit a high tumor uptake (∼10% ID g(-1)) after intravenous injection. In vitro and in vivo cancer treatment further confirm that Cu5FeS4-PEG could act as a novel therapeutic agent for PTT of cancer cells. Our study further promotes the potential applications of multifunctional nanomaterials in a range of tumor diagnoses and treatments. PMID:27341480

  18. Effects of infrared radiation and heat on human skin aging in vivo.

    PubMed

    Cho, Soyun; Shin, Mi Hee; Kim, Yeon Kyung; Seo, Jo-Eun; Lee, Young Mee; Park, Chi-Hyun; Chung, Jin Ho

    2009-08-01

    Sunlight damages human skin, resulting in a wrinkled appearance. Since natural sunlight is polychromatic, its ultimate effects on the human skin are the result of not only the action of each wavelength separately, but also interactions among the many wavelengths, including UV, visible light, and infrared (IR). In direct sunlight, the temperature of human skin rises to about 40 degrees C following the conversion of absorbed IR into heat. So far, our knowledge of the effects of IR radiation or heat on skin aging is limited. Recent work demonstrates that IR and heat exposure each induces cutaneous angiogenesis and inflammatory cellular infiltration, disrupts the dermal extracellular matrix by inducing matrix metalloproteinases, and alters dermal structural proteins, thereby adding to premature skin aging. This review provides a summary of current research on the effects of IR radiation and heat on aging in human skin in vivo.Journal of Investigative Dermatology Symposium Proceedings (2009) 14, 15-19; doi:10.1038/jidsymp.2009.7.

  19. Infrared radiative transfer through a regular array of cuboidal clouds

    NASA Technical Reports Server (NTRS)

    HARSHVARDHAN; Weinman, J. A.

    1981-01-01

    Infrared radiative transfer through a regular array of cuboidal clouds is studied and the interaction of the sides of the clouds with each other and the ground is considered. The theory is developed for black clouds and is extended to scattering clouds using a variable azimuth two-stream approximation. It is shown that geometrical considerations often dominate over the microphysical aspects of radiative transfer through the clouds. For example, the difference in simulated 10 micron brightness temperature between black isothermal cubic clouds and cubic clouds of optical depth 10, is less than 2 deg for zenith angles less than 50 deg for all cloud fractions when viewed parallel to the array. The results show that serious errors are made in flux and cooling rate computations if broken clouds are modeled as planiform. Radiances computed by the usual practice of area-weighting cloudy and clear sky radiances are in error by 2 to 8 K in brightness temperature for cubic clouds over a wide range of cloud fractions and zenith angles. It is also shown that the lapse rate does not markedly affect the exiting radiances for cuboidal clouds of unit aspect ratio and optical depth 10.

  20. A Thermal Infrared Radiation Parameterization for Atmospheric Studies

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah; Suarez, Max J.; Liang, Xin-Zhong; Yan, Michael M.-H.; Cote, Charles (Technical Monitor)

    2001-01-01

    This technical memorandum documents the longwave radiation parameterization developed at the Climate and Radiation Branch, NASA Goddard Space Flight Center, for a wide variety of weather and climate applications. Based on the 1996-version of the Air Force Geophysical Laboratory HITRAN data, the parameterization includes the absorption due to major gaseous absorption (water vapor, CO2, O3) and most of the minor trace gases (N2O, CH4, CFCs), as well as clouds and aerosols. The thermal infrared spectrum is divided into nine bands. To achieve a high degree of accuracy and speed, various approaches of computing the transmission function are applied to different spectral bands and gases. The gaseous transmission function is computed either using the k-distribution method or the table look-up method. To include the effect of scattering due to clouds and aerosols, the optical thickness is scaled by the single-scattering albedo and asymmetry factor. The parameterization can accurately compute fluxes to within 1% of the high spectral-resolution line-by-line calculations. The cooling rate can be accurately computed in the region extending from the surface to the 0.01-hPa level.

  1. Magnetic Resonance Imaging-Based Radiation-Absorbed Dose Estimation of {sup 166}Ho Microspheres in Liver Radioembolization

    SciTech Connect

    Seevinck, Peter R.; Maat, Gerrit H. van de; Wit, Tim C. de; Vente, Maarten A.D.; Nijsen, Johannes F.W.; Bakker, Chris J.G.

    2012-07-01

    Purpose: To investigate the potential of magnetic resonance imaging (MRI) for accurate assessment of the three-dimensional {sup 166}Ho activity distribution to estimate radiation-absorbed dose distributions in {sup 166}Ho-loaded poly (L-lactic acid) microsphere ({sup 166}Ho-PLLA-MS) liver radioembolization. Methods and Materials: MRI, computed tomography (CT), and single photon emission CT (SPECT) experiments were conducted on an anthropomorphic gel phantom with tumor-simulating gel samples and on an excised human tumor-bearing liver, both containing known amounts of {sup 166}Ho-PLLA-MS. Three-dimensional radiation-absorbed dose distributions were estimated at the voxel level by convolving the {sup 166}Ho activity distribution, derived from quantitative MRI data, with a {sup 166}Ho dose point-kernel generated by MCNP (Monte Carlo N-Particle transport code) and from Medical Internal Radiation Dose Pamphlet 17. MRI-based radiation-absorbed dose distributions were qualitatively compared with CT and autoradiography images and quantitatively compared with SPECT-based dose distributions. Both MRI- and SPECT-based activity estimations were validated against dose calibrator measurements. Results: Evaluation on an anthropomorphic phantom showed that MRI enables accurate assessment of local {sup 166}Ho-PLLA-MS mass and activity distributions, as supported by a regression coefficient of 1.05 and a correlation coefficient of 0.99, relating local MRI-based mass and activity calculations to reference values obtained with a dose calibrator. Estimated MRI-based radiation-absorbed dose distributions of {sup 166}Ho-PLLA-MS in an ex vivo human liver visually showed high correspondence to SPECT-based radiation-absorbed dose distributions. Quantitative analysis revealed that the differences in local and total amounts of {sup 166}Ho-PLLA-MS estimated by MRI, SPECT, and the dose calibrator were within 10%. Excellent agreement was observed between MRI- and SPECT-based dose

  2. ON THE ANISOTROPY OF NUCLEI MID-INFRARED RADIATION IN NEARBY ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Yang, Huan; Wang, JunXian; Liu, Teng E-mail: jxw@ustc.edu.cn

    2015-01-20

    In the center of active galactic nuclei (AGNs), the dusty torus absorbs the radiation from the central engine and reemits in mid-infrared (MIR). Observations have detected moderate anisotropy in the dust MIR emission, in the way that type 1 AGNs (type1s) are mildly brighter in MIR comparing with type 2 sources (type2s). However, type1s and type2s were found to follow statistically the same tight MIR-hard X-ray correlation, suggesting that the MIR emission is highly isotropic assuming that the hard X-ray radiation is inclination independent. We argue that this discrepancy could be solved considering that the hard X-ray emission in AGNs is also mildly anisotropic, as we recently discovered. To verify this diagram, we compare the subarcsecond 12 μm flux densities of type1s and type2s using the [O IV] λ25.89 μm emission line as an isotropic luminosity indicator. We find that on average type1s are brighter in nuclei 12 μm radiation by a factor of 2.6 ± 0.6 than type2s at given [O IV] λ25.89 μm luminosities, confirming the mild anisotropy of the nuclei 12 μm emission. We show that the anisotropy of the 12 μm emission we detected is in good agreement with radiative transfer models of clumpy tori. The fact that type1s and type2s follow the same tight MIR-hard X-ray correlation instead supports that both the MIR emission and hard X-ray emission in AGNs are mildly anisotropic.

  3. Caloric stimulation with near infrared radiation does not induce paradoxical nystagmus.

    PubMed

    Walther, L E; Asenov, D R; Di Martino, E

    2011-04-01

    Near infrared radiation can be used for warm stimulation in caloric irrigation of the equilibrium organ. Aim of this study was to determine whether near infrared radiation offers effective stimulation of the vestibular organ, whether it is well tolerated by the patients and especially whether it is a viable alternative to warm air stimulation in patients with defects of the tympanic membrane and radical mastoid cavities. Patients with perforations of the tympanic membrane (n = 15) and with radical mastoid cavities (n = 13) were tested both with near infrared radiation and warm dry air. A caloric-induced nystagmus could be seen equally effectively and rapidly in all patients. Contrary to stimulation with warm dry air, no paradoxical nystagmus was observed following caloric irrigation with a warm stimulus (near infrared radiation). Results of a questionnaire showed excellent patient acceptance of near infrared stimulation with no arousal effects or unpleasant feeling. In conclusion, near infrared radiation proved to be an alternative method of caloric irrigation to warm dry air in patients with tympanic membrane defects and radical mastoid cavities. Near infrared radiation is pleasant, quick, contact free, sterile and quiet. With this method an effective caloric warm stimulus is available. If near infrared radiation is used for caloric stimulus no evaporative heat loss occurs.

  4. Atlas of albedo and absorbed solar radiation derived from Nimbus 7 earth radiation budget data set, November 1985 to October 1987

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis; Rutan, David; Bess, T. Dale

    1992-01-01

    An atlas of monthly mean global contour maps of albedo and absorbed solar radiation is presented for 21 months from Nov. 1985 to Oct. 1987. These data were retrieved from measurements made by the shortwave wide-field-of-view radiometer of the Earth Radiation Budget (ERB) instrument aboard the Nimbus 7 spacecraft. Profiles of zonal mean albedos and absorbed solar radiation were tabulated. These geographical distributions are provided as a resource for researchers studying the radiation budget of the Earth. The El Nino/Southern Oscillation event of 1986-1987 is included in this data set. This atlas of albedo and absorbed solar radiation extends to 12 years the period covered by two similar atlases: NASA RP-1230 (Jul. 1975 - Oct. 1978) and NASA RP-1231 (Nov. 1978 - Oct. 1985). These three compilations complement the atlases of outgoing longwave radiation by Bess and Smith in NASA RP-1185, RP-1186, and RP-1261, which were also based on the Nimbus 6 and 7 ERB data.

  5. Analysis of the selected optical parameters of filters protecting against hazardous infrared radiation

    PubMed Central

    Gralewicz, Grzegorz; Owczarek, Grzegorz

    2016-01-01

    The paper analyses the selected optical parameters of protective optic filters used for protection of the eyes against hazardous radiation within the visible (VIS) and near infrared (NIR) spectrum range. The indexes characterizing transmission and reflection of optic radiation incident on the filter are compared. As it follows from the completed analysis, the newly developed interference filters provide more effective blocking of infrared radiation in comparison with the currently used protective filters. PMID:26327153

  6. Analysis of the selected optical parameters of filters protecting against hazardous infrared radiation.

    PubMed

    Gralewicz, Grzegorz; Owczarek, Grzegorz

    2016-09-01

    The paper analyses the selected optical parameters of protective optic filters used for protection of the eyes against hazardous radiation within the visible (VIS) and near infrared (NIR) spectrum range. The indexes characterizing transmission and reflection of optic radiation incident on the filter are compared. As it follows from the completed analysis, the newly developed interference filters provide more effective blocking of infrared radiation in comparison with the currently used protective filters.

  7. Improved micro-distribution of antibody-photon absorber conjugates after initial near infrared photoimmunotherapy (NIR-PIT).

    PubMed

    Nagaya, Tadanobu; Nakamura, Yuko; Sato, Kazuhide; Harada, Toshiko; Choyke, Peter L; Kobayashi, Hisataka

    2016-06-28

    Near infrared photoimmunotherapy (NIR-PIT), a targeted cancer therapy which uses an antibody-photo absorber conjugate (APC) and near infrared light exposure, dramatically improves nano-drug delivery into treated tumor beds due to enhanced vascular permeability. We investigated the micro-distribution of APCs in a variety of NIR-PIT treated tumors. Either cetuximab (cet) or trastuzumab (tra) conjugated with IR700 (cet-tra-IR700) was administered, as appropriate, to each mouse model of tumor. Tumor-bearing mice implanted with A431-GFP, MDAMB468-GFP, 3T3Her2-GFP or N87-GFP were separated into 5 groups: group 1=no treatment; group 2=cet-tra-IR700 i.v., no light exposure; group 3=cet-tra-IR700 i.v., NIR light exposure; group 4=cet-tra-IR700 i.v. and additional cet-tra-IR700 i.v. at 24h but no light exposure; group 5=cet-tra-IR700 i.v., NIR light exposure and additional cet-tra-IR700 i.v. immediately after NIR but no additional NIR light exposure. In vivo, ex vivo and microscopic fluorescence imaging was performed. Fluorescence from the surface of the tumor (s-tumor) was compared to fluorescence from deeper areas of the tumor (d-tumor). In general, there was no significant difference in the fluorescence intensity of GFP in the tumors among all groups, however the highest IR700 fluorescence intensity was consistently shown in group 5 tumors due to added APC after NIR-PIT. Fluorescence microscopy in all tumor types demonstrated that GFP relative fluorescence intensity (RFI) in s-tumor was significantly lower in group 3 and 5 (NIR-PIT groups) than in group 1, 2, and 4 (no NIR-PIT) yet there was no significant difference in d-tumor RFI among all groups. IR700 fluorescent RFI in the d-tumor was highest in group 5 (NIR-PIT+additional APC) compared to the other groups. Cell killing after NIR-PIT was primarily on the surface, however, APCs administered immediately after NIR-PIT penetrated deeper into tissue resulting in improved cell killing after a 2nd NIR-PIT session. This

  8. [Estimation of Fraction of Absorbed Photosynthetically Active Radiation for Winter Wheat Based on Hyperspectral Characteristic Parameters].

    PubMed

    Zhang, Chao; Cai, Huan-jie; Li, Zhi-jun

    2015-09-01

    Estimating fraction of absorbed photosynthetically active radiation (FPAR) precisely has great importance for detecting vegetation water content, energy and carbon cycle balance. Based on this, ASD FieldSpec 3 and SunScan canopy analyzer were applied to measure the canopy spectral reflectance and photosynthetically active radiation over whole growth stage of winter wheat. Canopy reflectance spectral data was used to build up 24 hyperspectral characteristic parameters and the correlation between FPAR and different spectral characteristic parameters were analyzed to establish the estimation model of FPAR for winter wheat. The results indicated that there were extremely significant correlations (p<0.01) between FPAR and hyperspectral characteristic parameters except the slope of blue edge (Db). The correlation coefficient between FPAR and the ratio of red edge area to blue edge area (VI4) was the highest, reaching at 0.836. Seven spectral parameters with higher correlation coefficient were selected to establish optimal linear and nonlinear estimation models of FPAR, and the best estimating models of FPAR were obtained by accuracy analysis. For the linear model, the inversin model between green edge and FPAR was the best, with R2, RMSE and RRMSE of predicted model reaching 0.679, 0.111 and 20.82% respectively. For the nonlinear model, the inversion model between VI2 (normalized ratio of green peak to red valley of reflectivity) and FPAR was the best, with R2, RMSE and RRMSE of predicted model reaching 0.724, 0.088 and 21.84% for. In order to further improve the precision of the model, the multiple linear regression and BP neural network methods were used to establish models with multiple high spectral parameters BP neural network model (R2=0.906, RMSE=0.08, RRMSE=16.57%) could significantly improve the inversion precision compared with the single variable model. The results show that using hyperspectral characteristic parameters to estimate FPAR of winter wheat is

  9. Estimating the direct radiative effect of absorbing aerosols overlying marine boundary layer clouds in the southeast Atlantic using MODIS and CALIOP

    NASA Astrophysics Data System (ADS)

    Meyer, Kerry; Platnick, Steven; Oreopoulos, Lazaros; Lee, Dongmin

    2013-05-01

    aerosols such as smoke strongly absorb solar radiation, particularly at ultraviolet and visible/near-infrared (VIS/NIR) wavelengths, and their presence above clouds can have considerable implications. It has been previously shown that they have a positive (i.e., warming) direct aerosol radiative effect (DARE) when overlying bright clouds. Additionally, they can cause biased passive instrument satellite retrievals in techniques that rely on VIS/NIR wavelengths for inferring the cloud optical thickness (COT) and effective radius (re) of underlying clouds, which can in turn yield biased above-cloud DARE estimates. Here we investigate Moderate Resolution Imaging Spectroradiometer (MODIS) cloud optical property retrieval biases due to overlying absorbing aerosols observed by Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and examine the impact of these biases on above-cloud DARE estimates. The investigation focuses on a region in the southeast Atlantic Ocean during August and September (2006-2011), where smoke from biomass burning in southern Africa overlies persistent marine boundary layer stratocumulus clouds. Adjusting for above-cloud aerosol attenuation yields increases in the regional mean liquid COT (averaged over all ocean-only liquid clouds) by roughly 6%; mean re increases by roughly 2.6%, almost exclusively due to the COT adjustment in the non-orthogonal retrieval space. It is found that these two biases lead to an underestimate of DARE. For liquid cloud Aqua MODIS pixels with CALIOP-observed above-cloud smoke, the regional mean above-cloud radiative forcing efficiency (DARE per unit aerosol optical depth (AOD)) at time of observation (near local noon for Aqua overpass) increases from 50.9Wm-2AOD-1 to 65.1Wm-2AOD-1 when using bias-adjusted instead of nonadjusted MODIS cloud retrievals.

  10. Biological Effects of Sunlight, Ultraviolet Radiation, Visible Light, Infrared Radiation and Vitamin D for Health.

    PubMed

    Holick, Michael F

    2016-03-01

    Humans evolved in sunlight and had depended on sunlight for its life giving properties that was appreciated by our early ancestors. However, for more than 40 years the lay press and various medical and dermatology associations have denounced sun exposure because of its association with increased risk for skin cancer. The goal of this review is to put into perspective the many health benefits that have been associated with exposure to sunlight, ultraviolet A (UVA) ultraviolet B (UVB), visible and infrared radiation. PMID:26977036

  11. Infrared [Fe II] Emission Lines from Radiative Atomic Shocks

    NASA Astrophysics Data System (ADS)

    Koo, Bon-Chul; Raymond, John C.; Kim, Hyun-Jeong

    2016-06-01

    [Fe II] emission lines are prominent in the infrared (IR) and important as diagnostic tools for radiative atomic shocks. We investigate the emission characteristics of [Fe II] lines using a shock code developed by te{raymond1979} with updated atomic parameters. We first review general characteristics of the IR [Fe II] emission lines from shocked gas, and derive their fluxes as a function of shock speed and ambient density. We have compiled available IR [Fe II] line observations of interstellar shocks and compare them to the ratios predicted from our model. The sample includes both young and old supernova remnants in the Galaxy and the Large Magellanic Cloud and several Herbig-Haro objects. We find that the observed ratios of the IR [Fe II] lines generally fall on our grid of shock models, but the ratios of some mid-IR lines, e.g., fethreefive/fetwofive, fefive/fetwofive, and fefive/feoneseven, are significantly offset from our model grid. We discuss possible explanations and conclude that while uncertainties in the shock modeling and the observations certainly exist, the uncertainty in atomic rates appears to be the major source of discrepancy.

  12. 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.

  13. Research on infrared radiation characteristics of Pyromark1200 high-temperature coating

    NASA Astrophysics Data System (ADS)

    Song, Xuyao; Huan, Kewei; Dong, Wei; Wang, Jinghui; Zang, Yanzhe; Shi, Xiaoguang

    2014-11-01

    Pyromark 1200 (Tempil Co, USA), which is a type of high-temperature high-emissivity coating, is silicon-based with good thermal radiation performance. Its stably working condition is at the temperature range 589~922 K thus a wide range of applications in industrial, scientific research, aviation, aerospace and other fields. Infrared emissivity is one of the most important factors in infrared radiation characteristics. Data on infrared spectral emissivity of Pyromark 1200 is in shortage, as well as the reports on its infrared radiation characteristics affected by its spray painting process, microstructure and thermal process. The results of this research show that: (1) The coating film critical thickness on the metal base is 10μm according to comparison among different types of spray painting process, coating film thickness, microstructure, which would influence the infrared radiation characteristics of Pyromark 1200 coating. The infrared spectral emissivity will attenuate when the coating film thickness is lower or much higher than that. (2) Through measurements, the normal infrared radiation characteristics is analyzed within the range at the temperature range 573~873 K under normal atmospheric conditions, and the total infrared spectral emissivity of Pyromark 1200 coating is higher than 0.93 in the 3~14 μm wavelength range. (3) The result of 72-hour aging test at the temperature 673 K which studied the effect of thermal processes on the infrared radiation characteristics of the coating shows that the infrared spectral emissivity variation range is approximately 0.01 indicating that Pyromark 1200 coating is with good stability. Compared with Nextel Velvet Coating (N-V-C) which is widely used in optics field, Pyromark 1200 high-temperature coating has a higher applicable temperature and is more suitable for spraying on the material surface which is in long-term operation under high temperature work conditions and requires high infrared spectral emissivity.

  14. Frequency selective infrared sensors

    SciTech Connect

    Davids, Paul; Peters, David W

    2014-11-25

    A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

  15. Frequency selective infrared sensors

    DOEpatents

    Davids, Paul; Peters, David W

    2013-05-28

    A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

  16. Measurements of a prototype synchrotron radiation pumped absorber for future light sources

    SciTech Connect

    Chou, T.S.; Foerster, C.L.; Halama, H.; Lanni, C.

    1988-01-01

    In the new generation of advanced synchrotron light sources, the conventional concept of distributed pumping is no longer suitable for removing the gas load caused by photon stimulated desorption (PSD). A new concept using a combination of photon absorber and pumping station has been designed, constructed, and installed in the U1OB beam line at the VUV ring of the National Synchrotron Light Source. The system consists of an electrically insulated water cooled copper block, a titanium sublimation pump, calibrated BA gauges, a calibrated RGA, and a known conductance. A photon beam 10 milliradian wide and 3.26 milliradian high, having critical energy of 500 eV, is directed on the absorber. PSD yield is studied as a function of total beam dose and absorber surface preparation. The results from this experiment, pump characteristics, design of an absorber pump for future light sources, and the pressure improvement factors will be presented. 5 refs., 7 figs., 1 tab.

  17. Satellite Infrared Radiation Measurements Prior to the Major Earthquakes

    NASA Technical Reports Server (NTRS)

    Ouzounov, Dimitar; Pulintes, S.; Bryant, N.; Taylor, Patrick; Freund, F.

    2005-01-01

    This work describes our search for a relationship between tectonic stresses and increases in mid-infrared (IR) flux as part of a possible ensemble of electromagnetic (EM) phenomena that may be related to earthquake activity. We present and &scuss observed variations in thermal transients and radiation fields prior to the earthquakes of Jan 22, 2003 Colima (M6.7) Mexico, Sept. 28 .2004 near Parkfield (M6.0) in California and Northern Sumatra (M8.5) Dec. 26,2004. Previous analysis of earthquake events has indicated the presence of an IR anomaly, where temperatures increased or did not return to its usual nighttime value. Our procedures analyze nighttime satellite data that records the general condtion of the ground after sunset. We have found from the MODIS instrument data that five days before the Colima earthquake the IR land surface nighttime temperature rose up to +4 degrees C in a 100 km radius around the epicenter. The IR transient field recorded by MODIS in the vicinity of Parkfield, also with a cloud free environment, was around +1 degree C and is significantly smaller than the IR anomaly around the Colima epicenter. Ground surface temperatures near the Parkfield epicenter four days prior to the earthquake show steady increase. However, on the night preceding the quake, a significant drop in relative humidity was indicated, process similar to those register prior to the Colima event. Recent analyses of continuous ongoing long- wavelength Earth radiation (OLR) indicate significant and anomalous variability prior to some earthquakes. The cause of these anomalies is not well understood but could be the result of a triggering by an interaction between the lithosphere-hydrosphere and atmospheric related to changes in the near surface electrical field and/or gas composition prior to the earthquake. The OLR anomaly usually covers large areas surrounding the main epicenter. We have found strong anomalies signal (two sigma) along the epicentral area signals on Dec 21

  18. Intercomparison of three microwave/infrared high resolution line-by-line radiative transfer codes

    NASA Astrophysics Data System (ADS)

    Schreier, F.; Garcia, S. Gimeno; Milz, M.; Kottayil, A.; Höpfner, M.; von Clarmann, T.; Stiller, G.

    2013-05-01

    An intercomparison of three line-by-line (lbl) codes developed independently for atmospheric sounding - ARTS, GARLIC, and KOPRA - has been performed for a thermal infrared nadir sounding application assuming a HIRS-like (High resolution Infrared Radiation Sounder) setup. Radiances for the HIRS infrared channels and a set of 42 atmospheric profiles from the "Garand dataset" have been computed. Results of this intercomparison and a discussion of reasons of the observed differences are presented.

  19. Productivity, absorbed photosynthetically active radiation, and light use efficiency in crops: implications for remote sensing of crop primary production.

    PubMed

    Gitelson, Anatoly A; Peng, Yi; Arkebauer, Timothy J; Suyker, Andrew E

    2015-04-01

    Vegetation productivity metrics such as gross primary production (GPP) at the canopy scale are greatly affected by the efficiency of using absorbed radiation for photosynthesis, or light use efficiency (LUE). Thus, close investigation of the relationships between canopy GPP and photosynthetically active radiation absorbed by vegetation is the basis for quantification of LUE. We used multiyear observations over irrigated and rainfed contrasting C3 (soybean) and C4 (maize) crops having different physiology, leaf structure, and canopy architecture to establish the relationships between canopy GPP and radiation absorbed by vegetation and quantify LUE. Although multiple LUE definitions are reported in the literature, we used a definition of efficiency of light use by photosynthetically active "green" vegetation (LUE(green)) based on radiation absorbed by "green" photosynthetically active vegetation on a daily basis. We quantified, irreversible slowly changing seasonal (constitutive) and rapidly day-to-day changing (facultative) LUE(green), as well as sensitivity of LUE(green) to the magnitude of incident radiation and drought events. Large (2-3-fold) variation of daily LUE(green) over the course of a growing season that is governed by crop physiological and phenological status was observed. The day-to-day variations of LUE(green) oscillated with magnitude 10-15% around the seasonal LUE(green) trend and appeared to be closely related to day-to-day variations of magnitude and composition of incident radiation. Our results show the high variability of LUE(green) between C3 and C4 crop species (1.43 g C/MJ vs. 2.24 g C/MJ, respectively), as well as within single crop species (i.e., maize or soybean). This implies that assuming LUE(green) as a constant value in GPP models is not warranted for the crops studied, and brings unpredictable uncertainties of remote GPP estimation, which should be accounted for in LUE models. The uncertainty of GPP estimation due to facultative and

  20. On the conversion of infrared radiation from fission reactor-based photon engine into parallel beam

    NASA Astrophysics Data System (ADS)

    Gulevich, Andrey V.; Levchenko, Vladislav E.; Loginov, Nicolay I.; Kukharchuk, Oleg F.; Evtodiev, Denis A.; Zrodnikov, Anatoly V.

    2002-01-01

    The efficiency of infrared radiation conversion from photon engine based on fission reactor into parallel photon beam is discussed. Two different ways of doing that are considered. One of them is to use the parabolic mirror to convert of infrared radiation into parallel photon beam. The another one is based on the use of special lattice consisting of numerous light conductors. The experimental facility and some results are described. .

  1. Development of models for thermal infrared radiation above and within plant canopies

    NASA Technical Reports Server (NTRS)

    Paw u, Kyaw T.

    1992-01-01

    Any significant angular dependence of the emitted longwave radiation could result in errors in remotely estimated energy budgets or evapotranspiration. Empirical data and thermal infrared radiation models are reviewed in reference to anisotropic emissions from the plant canopy. The biometeorological aspects of linking longwave models with plant canopy energy budgets and micrometeorology are discussed. A new soil plant atmosphere model applied to anisotropic longwave emissions from a canopy is presented. Time variation of thermal infrared emission measurements is discussed.

  2. Infrared Aerosol Radiative Forcing at the Surface and the Top of the Atmosphere

    NASA Technical Reports Server (NTRS)

    Markowicz, Krzysztof M.; Flatau, Piotr J.; Vogelmann, Andrew M.; Quinn, Patricia K.; Welton, Ellsworth J.

    2003-01-01

    We study the clear-sky aerosol radiative forcing at infrared wavelengths using data from the Aerosol Characterization Experiment (ACE-Asia) cruise of the NOAA R/V Ronald H. Brown. Limited number of data points is analyzed mostly from ship and collocated satellite values. An optical model is derived from chemical measurements, lidar profiles, and visible extinction measurements which is used to and estimate the infrared aerosol optical thickness and the single scattering albedo. The IR model results are compared to detailed Fourier Transform Interferometer based infrared aerosol forcing estimates, pyrgeometer based infrared downward fluxes, and against the direct solar forcing observations. This combined approach attests for the self-consistency of the optical model and allows to derive quantities such as the infrared forcing at the top of the atmosphere or the infrared optical thickness. The mean infrared aerosol optical thickness at 10 microns is 0.08 and the single scattering albedo is 0.55. The modeled infrared aerosol forcing reaches 10 W/sq m during the cruise, which is a significant contribution to the total direct aerosol forcing. The surface infrared aerosol radiative forcing is between 10 to 25% of the shortwave aerosol forcing. The infrared aerosol forcing at the top of the atmosphere can go up to 19% of the solar aerosol forcing. We show good agreement between satellite (CERES instrument) retrievals and model results at the top of the atmosphere. Over the Sea of Japan, the average infrared radiative forcing is 4.6 W/sq m in the window region at the surface and it is 1.5 W/sq m at top of the atmosphere. The top of the atmosphere IR forcing efficiency is a strong function of aerosol temperature while the surface IR forcing efficiency varies between 37 and 55 W/sq m (per infrared optical depth unit). and changes between 10 to 18 W/sq m (per infrared optical depth unit).

  3. Heat localization for targeted tumor treatment with nanoscale near-infrared radiation absorbers.

    PubMed

    Xie, Bin; Singh, Ravi; Torti, F M; Keblinski, Pawel; Torti, Suzy

    2012-09-21

    Focusing heat delivery while minimizing collateral damage to normal tissues is essential for successful nanoparticle-mediated laser-induced thermal cancer therapy. We present thermal maps obtained via magnetic resonance imaging characterizing laser heating of a phantom tissue containing a multiwalled carbon nanotube inclusion. The data demonstrate that heating continuously over tens of seconds leads to poor localization (∼ 0.5 cm) of the elevated temperature region. By contrast, for the same energy input, heat localization can be reduced to the millimeter rather than centimeter range by increasing the laser power and shortening the pulse duration. The experimental data can be well understood within a simple diffusive heat conduction model. Analysis of the model indicates that to achieve 1 mm or better resolution, heating pulses of ∼2 s or less need to be used with appropriately higher heating power. Modeling these data using a diffusive heat conduction analysis predicts parameters for optimal targeted delivery of heat for ablative therapy.

  4. Heat localization for targeted tumor treatment with nanoscale near-infrared radiation absorbers

    NASA Astrophysics Data System (ADS)

    Xie, Bin; Singh, Ravi; Torti, F. M.; Keblinski, Pawel; Torti, Suzy

    2012-09-01

    Focusing heat delivery while minimizing collateral damage to normal tissues is essential for successful nanoparticle-mediated laser-induced thermal cancer therapy. We present thermal maps obtained via magnetic resonance imaging characterizing laser heating of a phantom tissue containing a multiwalled carbon nanotube inclusion. The data demonstrate that heating continuously over tens of seconds leads to poor localization (∼ 0.5 cm) of the elevated temperature region. By contrast, for the same energy input, heat localization can be reduced to the millimeter rather than centimeter range by increasing the laser power and shortening the pulse duration. The experimental data can be well understood within a simple diffusive heat conduction model. Analysis of the model indicates that to achieve 1 mm or better resolution, heating pulses of ∼2 s or less need to be used with appropriately higher heating power. Modeling these data using a diffusive heat conduction analysis predicts parameters for optimal targeted delivery of heat for ablative therapy.

  5. Improved estimates of the radiation absorbed dose to the urinary bladder wall

    NASA Astrophysics Data System (ADS)

    Andersson, Martin; Minarik, David; Johansson, Lennart; Mattsson, Sören; Leide-Svegborn, Sigrid

    2014-05-01

    Specific absorbed fractions (SAFs) have been calculated as a function of the content in the urinary bladder in order to allow more realistic calculations of the absorbed dose to the bladder wall. The SAFs were calculated using the urinary bladder anatomy from the ICRP male and female adult reference computational phantoms. The urinary bladder and its content were approximated by a sphere with a wall of constant mass, where the thickness of the wall depended on the amount of urine in the bladder. SAFs were calculated for males and females with 17 different urinary bladder volumes from 10 to 800 mL, using the Monte Carlo computer program MCNP5, at 25 energies of mono-energetic photons and electrons ranging from 10 KeV to 10 MeV. The decay was assumed to be homogeneously distributed in the urinary bladder content and the urinary bladder wall, and the mean absorbed dose to the urinary bladder wall was calculated. The Monte Carlo simulations were validated against measurements made with thermoluminescent dosimeters. The SAFs obtained for a urine volume of 200 mL were compared to the values calculated for the urinary bladder wall using the adult reference computational phantoms. The mean absorbed dose to the urinary wall from 18F-FDG was found to be 77 µGy/MBq formales and 86 µGy/MBq for females, while for 99mTc-DTPA the mean absorbed doses were 80 µGy/MBq for males and 86 µGy/MBq for females. Compared to calculations using a constant value of the SAF from the adult reference computational phantoms, the mean absorbed doses to the bladder wall were 60% higher for 18F-FDG and 30% higher for 99mTc-DTPA using the new SAFs.

  6. High field CdS detector for infrared radiation

    NASA Technical Reports Server (NTRS)

    Tyagi, R. C.; Boer, K. W.; Hadley, H. C.; Robertson, J. B.

    1972-01-01

    New and highly sensitive method of detecting infrared irradiation makes possible solid state infrared detector which is more sensitive near room temperature than usual photoconductive low band gap semiconductor devices. Reconfiguration of high field domains in cadmium sulphide crystals provides basis for discovery.

  7. Average fetal depth in utero: data for estimation of fetal absorbed radiation dose

    SciTech Connect

    Ragozzino, M.W.; Breckle, R.; Hill, L.M.; Gray, J.E.

    1986-02-01

    To estimate fetal absorbed dose from radiographic examinations, the depth from the anterior maternal surface to the midline of the fetal skull and abdomen was measured by ultrasound in 97 pregnant women. The relationships between fetal depth, fetal presentation, and maternal parameters of height, weight, anteroposterior (AP) thickness, gestational age, placental location, and bladder volume were analyzed. Maternal AP thickness (MAP) can be estimated from gestational age, maternal height, and maternal weight. Fetal midskull and abdominal depths were nearly equal. Fetal depth normalized to MAP was independent or nearly independent of maternal parameters and fetal presentation. These data enable a reasonable estimation of absorbed dose to fetal brain, abdomen, and whole body.

  8. Electro-optic detection of continuous-wave mid-infrared radiation.

    PubMed

    Cao, Hua; Nahata, Ajay

    2002-01-01

    We demonstrate coherent detection of continuous-wave mid-infrared radiation. This radiation is produced by use of conventional difference-frequency mixing and detected via the linear electro-optic effect. The detection process allows for the simultaneous measurement of the amplitude and phase properties of the infrared field. Both processes require an amplitude-modulated optical beam that is derived from the superimposed output of two single-frequency lasers. With appropriate choice of lasers and nonlinear optical crystals, the technique may be applied to any wavelength throughout the far and mid infrared.

  9. Effective disinfection of rough rice using infrared radiation heating.

    PubMed

    Wang, Bei; Khir, Ragab; Pan, Zhongli; El-Mashad, Hamed; Atungulu, Griffiths G; Ma, Haile; McHugh, Tara H; Qu, Wenjuan; Wu, Bengang

    2014-09-01

    The objective of this study was to investigate the effect of infrared (IR) heating and tempering treatments on disinfection of Aspergillus flavus in freshly harvested rough rice and storage rice. Rice samples with initial moisture contents (IMCs) of 14.1 to 27.0% (wet basis) were infected with A. flavus spores before the tests. The infected samples were heated by IR radiation to 60°C in less than 1 min, and then samples were tempered at 60°C for 5, 10, 20, 30, 60, or 120 min. High heating rates and corresponding high levels of moisture removal were achieved using IR heating. The highest total moisture removal was 5.3% for the fresh rice with an IMC of 27.0% after IR heating and then 120 min of tempering. IR heating followed by tempering for 120 min resulted in 2.5- and 8.3-log reductions of A. flavus spores in rough rice with the lowest and highest IMCs, respectively. To study the effect on disinfection of rewetting dried storage rice, the surface of the dry rice was rewetted to achieve IMCs of 14.7 to 19.4% (wet basis). The rewetting process for the dry rice had a significant effect on disinfection. IR heating followed by tempering for 60 min resulted in 7.2-log reductions in A. flavus on rewetted rough rice. The log-linear plus tail model was applied to estimate the tempering time needed to achieve a 5-log reduction of A. flavus in rice of different IMCs. At least 30 and 20 min of tempering were needed for fresh rice and rewetted rice, respectively, with the highest IMCs. The recommended conditions of simultaneous disinfection and drying for fresh rice was IR heating to 60°C followed by tempering for 120 min and natural cooling, resulting in a final MC of 16.5 to 22.0%, depending on the IMC. For the rewetted dry rice with an IMC of 19.4%, the recommended condition for disinfection and drying involved only 20 min of tempering. The final MC of the sample was 13.8%, which is a safe MC for storage rice.

  10. 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

  11. Eye safety related to near infrared radiation exposure to biometric devices.

    PubMed

    Kourkoumelis, Nikolaos; Tzaphlidou, Margaret

    2011-01-01

    Biometrics has become an emerging field of technology due to its intrinsic security features concerning the identification of individuals by means of measurable biological characteristics. Two of the most promising biometric modalities are iris and retina recognition, which primarily use nonionizing radiation in the infrared region. Illumination of the eye is achieved by infrared light emitting diodes (LEDs). Even if few LED sources are capable of causing direct eye damage as they emit incoherent light, there is a growing concern about the possible use of LED arrays that might pose a potential threat. Exposure to intense coherent infrared radiation has been proven to have significant effects on living tissues. The purpose of this study is to explore the biological effects arising from exposing the eye to near infrared radiation with reference to international legislation. PMID:21380486

  12. Eye safety related to near infrared radiation exposure to biometric devices.

    PubMed

    Kourkoumelis, Nikolaos; Tzaphlidou, Margaret

    2011-03-01

    Biometrics has become an emerging field of technology due to its intrinsic security features concerning the identification of individuals by means of measurable biological characteristics. Two of the most promising biometric modalities are iris and retina recognition, which primarily use nonionizing radiation in the infrared region. Illumination of the eye is achieved by infrared light emitting diodes (LEDs). Even if few LED sources are capable of causing direct eye damage as they emit incoherent light, there is a growing concern about the possible use of LED arrays that might pose a potential threat. Exposure to intense coherent infrared radiation has been proven to have significant effects on living tissues. The purpose of this study is to explore the biological effects arising from exposing the eye to near infrared radiation with reference to international legislation.

  13. Variable waveband infrared imager

    SciTech Connect

    Hunter, Scott R.

    2013-06-11

    A waveband imager includes an imaging pixel that utilizes photon tunneling with a thermally actuated bimorph structure to convert infrared radiation to visible radiation. Infrared radiation passes through a transparent substrate and is absorbed by a bimorph structure formed with a pixel plate. The absorption generates heat which deflects the bimorph structure and pixel plate towards the substrate and into an evanescent electric field generated by light propagating through the substrate. Penetration of the bimorph structure and pixel plate into the evanescent electric field allows a portion of the visible wavelengths propagating through the substrate to tunnel through the substrate, bimorph structure, and/or pixel plate as visible radiation that is proportional to the intensity of the incident infrared radiation. This converted visible radiation may be superimposed over visible wavelengths passed through the imaging pixel.

  14. Latest Development of Infrared Radiation Heating for Food Processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infrared (IR) heating could be an alternative technology for thermal and dehydration processing of food and agricultural products with many advantages, including high process and energy efficiencies, high product quality, improved food safety and reduced environmental pollution. This paper reviews ...

  15. Inferring total canopy APAR from PAR bidirectional reflectances and vegetation indices in tallgrass prairie. [Absorbed Photosynthetically Active Radiation

    NASA Technical Reports Server (NTRS)

    Middleton, Elizabeth M.

    1992-01-01

    The fraction of photosynthetically active radiation (PAR) absorbed by a vegetated canopy (APARc) or landscape (APARs) is a critical parameter in climate processes. A grassland study examined: 1) whether APARs can be estimated from PAR bidirectional exitance fractions; and 2) whether APARs is correlated with spectral vegetation indices (SVIs). Data were acquired with a high resolution continuous spectroradiometer at 4 sun angles on grassland sites. APARs was computed from the scattered surface PAR exitance fractions. The nadir APARs value was the most variable diurnally; it provided a good estimate of the average surface APARs at 95 percent. APARc was best represented by exitance factors between 30-60* forward.

  16. Estimating the infrared radiation wavelength emitted by a remote control device using a digital camera

    NASA Astrophysics Data System (ADS)

    Catelli, Francisco; Giovannini, Odilon; Dall Agnol Bolzan, Vicente

    2011-03-01

    The interference fringes produced by a diffraction grating illuminated with radiation from a TV remote control and a red laser beam are, simultaneously, captured by a digital camera. Based on an image with two interference patterns, an estimate of the infrared radiation wavelength emitted by a TV remote control is made.

  17. Estimating the Infrared Radiation Wavelength Emitted by a Remote Control Device Using a Digital Camera

    ERIC Educational Resources Information Center

    Catelli, Francisco; Giovannini, Odilon; Bolzan, Vicente Dall Agnol

    2011-01-01

    The interference fringes produced by a diffraction grating illuminated with radiation from a TV remote control and a red laser beam are, simultaneously, captured by a digital camera. Based on an image with two interference patterns, an estimate of the infrared radiation wavelength emitted by a TV remote control is made. (Contains 4 figures.)

  18. Low-intensity infrared laser radiation influence on the tumor growth

    NASA Astrophysics Data System (ADS)

    Cheida, A. A.; Efimova, E. G.

    2005-08-01

    Infrared laser radiation of low intensity in exposition dose of 25-35 mJicm2 does not cause progress the tumor process. Moreover, disturbing the blood flow in the tumor due to changing synthesis of norepinephrine and histamine this radiation contributes to the damage of the tumor tissue accompanied by the beginning of adaptation reaction in the organism.

  19. Seebeck nanoantennas for the detection and characterization of infrared radiation.

    PubMed

    Briones, Edgar; Cuadrado, Alexander; Briones, Joel; Díaz de León, Ramón; Martínez-Antón, Juan Carlos; McMurtry, Stefan; Hehn, Michel; Montaigne, François; Alda, Javier; González, Francisco Javier

    2014-10-20

    Arrays of metallic thermocouples in the shape of spiral nanoantennas are proposed as infrared detectors, which use the thermoelectric properties of the metallic interfaces to generate electrical DC signals. The responsivity of these types of antennas is evaluated from both theoretical and numerical perspectives pointing out its potential as infrared sensors. Moreover, the same structures can be used to characterize the state of polarization of the optical near fields with a spatial resolution comparable to the wavelength.

  20. Silicone rubber curing by high intensity infrared radiation

    SciTech Connect

    Huang, T.; Tsai, J.; Cherng, C.; Chen, J.

    1994-08-10

    A high-intensity (12 kW) and compact (80 cm) infrared heating oven for fast curing (12 seconds) of tube-like silicone rubber curing studies is reported. Quality inspection by DSC and DMA and results from pilot-scale curing oven all suggest that infrared heating provides a better way of vulcanization regarding to curing time, quality, cost, and spacing over conventional hot air heating. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  1. Infrared A radiation promotes survival of human melanocytes carrying ultraviolet radiation-induced DNA damage.

    PubMed

    Kimeswenger, Susanne; Schwarz, Agatha; Födinger, Dagmar; Müller, Susanne; Pehamberger, Hubert; Schwarz, Thomas; Jantschitsch, Christian

    2016-06-01

    The link between solar radiation and melanoma is still elusive. Although infrared radiation (IR) accounts for over 50% of terrestrial solar energy, its influence on human skin is not well explored. There is increasing evidence that IR influences the expression patterns of several molecules independently of heat. A previous in vivo study revealed that pretreatment with IR might promote the development of UVR-induced non-epithelial skin cancer and possibly of melanoma in mice. To expand on this, the aim of the present study was to evaluate the impact of IR on UVR-induced apoptosis and DNA repair in normal human epidermal melanocytes. The balance between these two effects is a key factor of malignant transformation. Human melanocytes were exposed to physiologic doses of IR and UVR. Compared to cells irradiated with UVR only, simultaneous exposure to IR significantly reduced the apoptotic rate. However, IR did not influence the repair of UVR-induced DNA damage. IR partly reversed the pro-apoptotic effects of UVR via modification of the expression and activity of proteins mainly of the extrinsic apoptotic pathway. In conclusion, IR enhances the survival of melanocytes carrying UVR-induced DNA damage and thereby might contribute to melanomagenesis.

  2. 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

  3. Radiation absorbed dose estimates for oxygen-15 radiopharmaceuticals (H2( V)O, C VO, O VO) in newborn infants

    SciTech Connect

    Powers, W.J.; Stabin, M.; Howse, D.; Eichling, J.O.; Herscovitch, P.

    1988-12-01

    In preparation for measurement of regional cerebral oxygen metabolism by positron emission tomography, radiation absorbed dose estimates for 19 internal organs, blood, and total body were calculated for newborn infants following bolus intravenous administration of H2( V)O and brief inhalation of C VO and O VO. Cumulated activity for each radiopharmaceutical was calculated from a compartmental model based on the known biologic behavior of the compound. Values for mean absorbed dose/unit cumulated activity (S) for internal organs and total body were based on a newborn phantom. S was separately calculated for blood. Total radiopharmaceutical absorbed dose estimates necessary to measure cerebral oxygen metabolism in a 3.51-kg infant based on 0.7 mCi/kg H2( V)O and 1 mCi/kg C VO and O VO were determined to be 1.6 rad to the lung (maximum organ dose), 0.28 rad to the marrow, 0.46 rad to the gonads, and 0.22 rad to total body. These values are similar to those for current clinical nuclear medicine procedures employing /sup 99m/Tc in newborn infants.

  4. Photosynthesis, Growth, and Ultraviolet Irradiance Absorbance of Cucurbita pepo L. Leaves Exposed to Ultraviolet-B Radiation (280-315 nm) 1

    PubMed Central

    Sisson, William B.

    1981-01-01

    Net photosynthesis, growth, and ultraviolet (UV) radiation absorbance were determined for the first leaf of Cucurbita pepo L. exposed to two levels of UV-B irradiation and a UV-B radiation-free control treatment. Absorbance by extracted flavonoid pigments and other UV-B radiation-absorbing compounds from the first leaves increased with time and level of UV-B radiation impinging on leaf surfaces. Although absorbance of UV-B radiation by extracted pigments increased substantially, UV-B radiation attenuation apparently was insufficient to protect completely the photosynthetic apparatus or leaf growth processes. Leaf expansion was repressed by daily exposure to 1365 Joules per meter per day of biologically effective UV-B radiation but not by exposure to 660 Joules per meter per day. Photosynthesis measured through ontogenesis of the first leaf was depressed by both UV-B radiation treatments. Repression of photosynthesis by UV-B radiation was especially evident during the ontogenetic period of maximum photosynthetic activity. PMID:16661610

  5. Non-coherent near infrared radiation protects normal human dermal fibroblasts from solar ultraviolet toxicity.

    PubMed

    Menezes, S; Coulomb, B; Lebreton, C; Dubertret, L

    1998-10-01

    The sun is the most important and universal source of non-ionizing radiation shed on human populations. Life evolved on Earth bathed by this radiation. Solar UV damages cells, leading to deleterious conditions such as photoaging and carcinogenesis in human skin. During the process of evolution, the cells selected dark- and light-dependent repair mechanisms as a defence against these hazardous effects. This study describes the induction by non-coherent infrared radiation (700-2000 nm), in the absence of rising temperature, of a strong cellular defense against solar UV cytotoxicity as well as induction of cell mitosis. Blocking mitoses with arabinoside-cytosine or protein synthesis with cycloheximide did not abolish the protection, leading to the conclusion that this protection is independent of cell division and of protein neosynthesis. The protection provided by infrared radiation against solar UV radiation is shown to be a long-lasting (at least 24 h) and cumulatif phenomenon. Infrared radiation does not protect the lipids in cellular membranes against UVA induced peroxidation. The protection is not mediated by heat shock proteins. Living organisms on the Earth's surface are bathed by infrared radiation every day, before being submitted to solar UV. Thus, we propose that this as yet undescribed natural process of cell protection against solar UV, acquired and preserved through evolutional selection, plays an important role in life maintenance. Understanding and controlling this mechanism could provide important keys to the prevention of solar UV damage of human skin.

  6. A unique combination of infrared and microwave radiation accelerates wound healing.

    PubMed

    Schramm, J Mark; Warner, Dave; Hardesty, Robert A; Oberg, Kerby C

    2003-01-01

    Light or electromagnetic radiation has been reported to enhance wound healing. The use of selected spectra, including infrared and microwave, has been described; however, no studies to date have examined the potential benefit of combining these spectra. In this study, a device that emits electromagnetic radiation across both the infrared and microwave ranges was used. To test the effects of this unique electromagnetic radiation spectrum on wound healing, two clinically relevant wound-healing models (i.e., tensile strength of simple incisions and survival of McFarlane flaps) were selected. After the creation of a simple full-thickness incision (n = 35 rats) or a caudally based McFarlane flap (n = 33 rats), animals were randomly assigned to one of three treatment groups: untreated control, infrared, or combined electromagnetic radiation. Treatment was administered for 30 minutes, twice daily for 18 days in animals with simple incisions, and 15 days in animals with McFarlane flaps. The wound area or flap was harvested and analyzed, blinded to the treatment regimens. A p value of less than 0.05 obtained by analysis of variance was considered to be statistically significant. Animals receiving combined electromagnetic radiation demonstrated increased tensile strength (2.62 N/mm2) compared with animals receiving infrared radiation (2.36 N/mm2) or untreated controls (1.73 N/mm2, p < 0.001). Animals with McFarlane flaps receiving combined electromagnetic radiation had increased flap survival (78.0 percent) compared with animals receiving infrared radiation (69.7 percent) and untreated controls (63.1 percent, p < 0.01). Thus, combined electromagnetic radiation provided a distinct advantage in wound healing that might augment current treatment regimens.

  7. Invisible Misconceptions: Student Understanding of Ultraviolet and Infrared Radiation

    ERIC Educational Resources Information Center

    Libarkin, Julie C.; Asghar, Anila; Crockett, C.; Sadler, Philip

    2011-01-01

    The importance of nonvisible wavelengths for the study of astronomy suggests that student understanding of nonvisible light is an important consideration in astronomy classrooms. Questionnaires, interviews, and panel discussions were used to investigate 6-12 student and teacher conceptions of ultraviolet (UV) and infrared (IR). Alternative…

  8. Drying characteristics and quality of bananas under infrared radiation heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hot air (HA) drying of banana has low drying efficiency and results in undesirable product quality. The objectives of this research were to investigate the feasibility of infrared (IR) heating to improve banana drying rate, evaluate quality of the dried product, and establish models for predicting d...

  9. Development and commercialization of emerging infrared radiation food processing technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to demonstrate a newly developed simultaneous infrared dry-blanching and dehydration (SIRDBD) technology on an industrial scale, a mobile and continuous IR heating system was built and tested to examine its performance for SIRDBD of sliced and diced potatoes. The mobile IR heating equipment...

  10. Effective disinfection of rough rice using infrared radiation heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to investigate the effect of infrared (IR) heating and tempering treatments on disinfection of Aspergillus flavus in freshly harvested rough rice and storage rice. Rice samples with initial moisture contents (IMCs) of 14.1 to 27.0% (wet basis) were infected with A. fl...

  11. AGN Obscuration Through Dusty Infrared Dominated Flows. II. Multidimensional, Radiation-Hydrodynamics Modeling

    NASA Technical Reports Server (NTRS)

    Dorodnitsyn, Anton; Kallman, Tim; Bisno\\vatyiI-Kogan, Gennadyi

    2011-01-01

    We explore a detailed model in which the active galactic nucleus (AGN) obscuration results from the extinction of AGN radiation in a global ow driven by the pressure of infrared radiation on dust grains. We assume that external illumination by UV and soft X-rays of the dusty gas located at approximately 1pc away from the supermassive black hole is followed by a conversion of such radiation into IR. Using 2.5D, time-dependent radiation hydrodynamics simulations in a ux-limited di usion approximation we nd that the external illumination can support a geometrically thick obscuration via out ows driven by infrared radiation pressure in AGN with luminosities greater than 0:05 L(sub edd) and Compton optical depth, Tau(sub T) approx > & 1.

  12. Numerical study on the influence of aluminum on infrared radiation signature of exhaust plume

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Ye, Qing-qing; Li, Shi-peng; Wang, Ning-fei

    2013-09-01

    The infrared radiation signature of exhaust plume from solid propellant rockets has been widely mentioned for its important realistic meaning. The content of aluminum powder in the propellants is a key factor that affects the infrared radiation signature of the plume. The related studies are mostly on the conical nozzles. In this paper, the influence of aluminum on the flow field of plume, temperature distribution, and the infrared radiation characteristics were numerically studied with an object of 3D quadrate nozzle. Firstly, the gas phase flow field and gas-solid multi phase flow filed of the exhaust plume were calculated using CFD method. The result indicates that the Al203 particles have significant effect on the flow field of plume. Secondly, the radiation transfer equation was solved by using a discrete coordinate method. The spectral radiation intensity from 1000-2400 cm-1 was obtained. To study the infrared radiation characteristics of exhaust plume, an exceptional quadrate nozzle was employed and much attention was paid to the influences of Al203 particles in solid propellants. The results could dedicate the design of the divert control motor in such hypervelocity interceptors or missiles, or be of certain meaning to the improvement of ingredients of solid propellants.

  13. Theoretical analysis of infrared radiation shields of spacecraft

    NASA Technical Reports Server (NTRS)

    Shealy, D. L.

    1984-01-01

    For a system of N diffuse, gray body radiation shields which view only adjacent surfaces and space, the net radiation method for enclosures has been used to formulate a system of linear, nonhomogeneous equations in terms of the temperatures to the fourth power of each surface in the coupled system of enclosures. The coefficients of the unknown temperatures in the system of equations are expressed in terms of configuration factors between adjacent surfaces and the emissivities. As an application, a system of four conical radiation shields for a spin stabilized STARPROBE spacecraft has been designed and analyzed with respect to variations of the cone half angles, the intershield spacings, and emissivities.

  14. Balloon measurements of the far-infrared background radiation.

    NASA Technical Reports Server (NTRS)

    Muehlner, D.; Weiss, R.

    1973-01-01

    Description of a balloon-borne radiometer designed to make direct measurements of the background radiation in the spectral range from 1 to 20 cm, and evaluation of the results of two balloon flights performed with the aid of this radiometer. Measurements in five different passbands in the spectral region below 20 per cm were made with a liquid-helium-cooled radiometer in two flights at approximately 40-km altitude. The results obtained are found to be consistent with a 2.7 K thermal radiation background. In addition, an atmospheric radiation of certain magnitude is found to dominate the region above 11 per cm.

  15. A climate index derived from satellite measured spectral infrared radiation. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Abel, M. D.; Fox, S. K.

    1982-01-01

    The vertical infrared radiative emitting structure (VIRES) climate index, based on radiative transfer theory and derived from the spectral radiances typically used to retrieve temperature profiles, is introduced. It is assumed that clouds and climate are closely related and a change in one will result in a change in the other. The index is a function of the cloud, temperature, and moisture distributions. It is more accurately retrieved from satellite data than is cloudiness per se. The VIRES index is based upon the shape and relative magnitude of the broadband weighting function of the infrared radiative transfer equation. The broadband weighting curves are retrieved from simulated satellite infrared sounder data (spectral radiances). The retrieval procedure is described and the error error sensitivities of the method investigated. Index measuring options and possible applications of the VIRES index are proposed.

  16. Absorbed doses and radiation damage during the 11 years of LEP operation

    NASA Astrophysics Data System (ADS)

    Schönbacher, H.; Tavlet, M.

    2004-03-01

    During the 11 years of operation of the large electron-positron collider (LEP), synchrotron radiation was emitted in the tunnel. This ionizing radiation induced degradation in organic insulators and structural materials, as well as in electronics. Annual dosimetric measurements have shown that the level of radiation increased with the ninth power of the beam energy. During the machine shutdowns and at the end of the operation, samples of rigid and flexible polymeric insulators (magnet-coil resins and cable insulations) were taken out and checked for their integrity. The test results are compared with the results obtained during the qualification of the materials, 12-15 years ago. At that time, lifetime predictions were made; they are now compared with the real time-aged materials.

  17. An inverse method for flue gas shielded metal surface temperature measurement based on infrared radiation

    NASA Astrophysics Data System (ADS)

    Zhang, B.; Xu, C. L.; Wang, S. M.

    2016-07-01

    The infrared temperature measurement technique has been applied in various fields, such as thermal efficiency analysis, environmental monitoring, industrial facility inspections, and remote temperature sensing. In the problem of infrared measurement of the metal surface temperature of superheater surfaces, the outer wall of the metal pipe is covered by radiative participating flue gas. This means that the traditional infrared measurement technique will lead to intolerable measurement errors due to the absorption and scattering of the flue gas. In this paper, an infrared measurement method for a metal surface in flue gas is investigated theoretically and experimentally. The spectral emissivity of the metal surface, and the spectral absorption and scattering coefficients of the radiative participating flue gas are retrieved simultaneously using an inverse method called quantum particle swarm optimization. Meanwhile, the detected radiation energy simulated using a forward simulation method (named the source multi-flux method) is set as the input of the retrieval. Then, the temperature of the metal surface detected by an infrared CCD camera is modified using the source multi-flux method in combination with these retrieved physical properties. Finally, an infrared measurement system for metal surface temperature is built to assess the proposed method. Experimental results show that the modified temperature is closer to the true value than that of the direct measured temperature.

  18. Molecular action mechanisms of solar infrared radiation and heat on human skin.

    PubMed

    Akhalaya, M Ya; Maksimov, G V; Rubin, A B; Lademann, J; Darvin, M E

    2014-07-01

    The generation of ROS underlies all solar infrared-affected therapeutic and pathological cutaneous effects. The signaling pathway NF-kB is responsible for the induced therapeutic effects, while the AP-1 for the pathological effects. The different signaling pathways of infrared-induced ROS and infrared-induced heat shock ROS were shown to act independently multiplying the influence on each other by increasing the doses of irradiation and/or increasing the temperature. The molecular action mechanisms of solar infrared radiation and heat on human skin are summarized and discussed in detail in the present paper. The critical doses are determined. Protection strategies against infrared-induced skin damage are proposed.

  19. Validity criterion of the radiative Fourier law for an absorbing and scattering medium.

    PubMed

    Gomart, Hector; Taine, Jean

    2011-02-01

    For radiative heat transfer applications, in particular in homogenized phases of porous media, an exhaustive and accurate validity criterion of the radiative Fourier law, depending only on the logarithmic derivative of the temperature field and an effective absorption coefficient, accounting for possible multiple scattering phenomena, has been established for a semitransparent medium. This effective absorption coefficient is expressed as a function of the absorption coefficient, the albedo, and the scattering asymmetry parameter. The criterion can be applied to semitransparent media that do not follow Beer's laws related to extinction, absorption, and scattering.

  20. Relations for local radiative heat transfer between rectangular boundaries of an absorbing-emitting medium

    NASA Technical Reports Server (NTRS)

    Siegel, R.

    1993-01-01

    An analytical solution was obtained by Siegel (1991, 1992) for local boundary heat fluxes by a radiating medium at uniform temperature in a 2D rectangular region. It is shown here that, after local fluxes from the medium to the walls have been evaluated, it is very easy to compute local fluxes arriving from the adjacent and opposite walls. This extends the previous analysis and provides convenient relations to include radiation from a black boundary, each side of the rectangle being at a different uniform temperature. The final expressions are helpful in performing spectral calculations that must be made for many spectral bands.

  1. Fabrication of an Absorber-Coupled MKID Detector and Readout for Sub-Millimeter and Far-Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Brown, Ari-David; Hsieh, Wen-Ting; Moseley, S. Harvey; Stevenson, Thomas R.; U-yen, Kongpop; Wollack, Edward J.

    2010-01-01

    We have fabricated absorber-coupled microwave kinetic inductance detector (MKID) arrays for sub-millimeter and farinfrared astronomy. Each detector array is comprised of lambda/2 stepped impedance resonators, a 1.5µm thick silicon membrane, and 380µm thick silicon walls. The resonators consist of parallel plate aluminum transmission lines coupled to low impedance Nb microstrip traces of variable length, which set the resonant frequency of each resonator. This allows for multiplexed microwave readout and, consequently, good spatial discrimination between pixels in the array. The Al transmission lines simultaneously act to absorb optical power and are designed to have a surface impedance and filling fraction so as to match the impedance of free space. Our novel fabrication techniques demonstrate high fabrication yield of MKID arrays on large single crystal membranes and sub-micron front-to-back alignment of the microstrip circuit.

  2. Absorption of visible radiation in atmosphere containing mixtures of absorbing and nonabsorbing particles

    NASA Technical Reports Server (NTRS)

    Ackerman, T. P.; Toon, O. B.

    1981-01-01

    The presence of a strongly absorbing material, tentatively identified as graphitic carbon, or 'soot', is indicated by measurements of single-scattering albedo of tropospheric aerosols. Although theoretical calculations based on models of the ways in which soot may mix with other aerosol materials yield the single-scattering albedo values of 0.6, accounted for by a minimum 20% soot by volume, in urban regions and 0.8, yielded by 1-5% soot by volume, in rural settings, it is found that these same values can be produced by similar amounts of the iron oxide magnetite. Magnetite is shown to be indistinguishable from soot by optical measurements performed on bulk samples, and calculation of various mixtures of soot indicate the difficulty of determining aerosol composition by optical scattering techniques.

  3. Effect of rare earth Ce on the far infrared radiation property of iron ore tailings ceramics

    SciTech Connect

    Liu, Jie; Meng, Junping; Liang, Jinsheng; Duan, Xinhui; Huo, Xiaoli; Tang, Qingguo

    2015-06-15

    Highlights: • Detailed process proposed for preparation of iron ore tailings ceramics. • Replace natural minerals with iron ore tailings as raw materials for preparing functional ceramics. • Impact mechanism of Ce on far infrared ceramics, as well as its optimum addition amounts can be obtained. • Propose a new perspective on considering the mechanism of far infrared radiation. - Abstract: A kind of far infrared radiation ceramics was prepared by using iron ore tailings, CaCO{sub 3} and SiO{sub 2} as main raw materials, and Ce as additive. The result of Fourier transform infrared spectroscopy showed that the sample exhibits excellent radiation value of 0.914 when doping 7 wt.% Ce. Ce{sup 4+} dissolved into iron diopside and formed interstitial solid solution with it sintered at 1150 °C. The oxidation of Fe{sup 2+} to Fe{sup 3+} caused by Ce{sup 4+} led to a decrease of crystallite sizes and enhancement of Mg–O and Fe–O vibration in iron diopside, which consequently improved the far infrared radiation properties of iron ore tailings ceramics.

  4. Thermal radiation characteristics of silicon inverse opal in mid infrared range

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Xie, Kai

    2015-03-01

    A binary solvent with large density was used as dispersant for silica spheres, in which silica spheres with large diameter can suspend steadily and disperse very well. With this suspension, fine opals with 2100 nm SiO2 mono-disperse spheres were successfully prepared by solvent evaporation method. Low pressure vapor deposition method was then used to fill the voids of the silica opals with Si, and silicon inverse opal with photonic band gaps in mid infrared region was obtained. The infrared radiation characteristic of resulted sample was examined. It is shown that silicon inverse opal structure is effective in suppressing silicon thermal radiation in the photonic band gap spectral region.

  5. Toward the development of transcriptional biodosimetry for the identification of irradiated individuals and assessment of absorbed radiation dose.

    PubMed

    Brzóska, Kamil; Kruszewski, Marcin

    2015-08-01

    The most frequently used and the best established method of biological dosimetry at present is the dicentric chromosome assay, which is poorly suitable for a mass casualties scenario. This gives rise to the need for the development of new, high-throughput assays for rapid identification of the subjects exposed to ionizing radiation. In the present study, we tested the usefulness of gene expression analysis in blood cells for biological dosimetry. Human peripheral blood from three healthy donors was X-irradiated with doses of 0 (control), 0.6, and 2 Gy. The mRNA level of 16 genes (ATF3, BAX, BBC3, BCL2, CDKN1A, DDB2, FDXR, GADD45A, GDF15, MDM2, PLK3, SERPINE1, SESN2, TNFRSF10B, TNFSF4, and VWCE) was assessed by reverse transcription quantitative PCR 6, 12, 24, and 48 h after exposure with ITFG1 and DPM1 used as a reference genes. The panel of radiation-responsive genes was selected comprising GADD45A, CDKN1A, BAX, BBC3, DDB2, TNFSF4, GDF15, and FDXR. Cluster analysis showed that ΔC t values of the selected genes contained sufficient information to allow discrimination between irradiated and non-irradiated blood samples. The samples were clearly grouped according to the absorbed doses of radiation and not to the time interval after irradiation or to the blood donor. PMID:25972268

  6. Seasonal Variation in Fraction of Absorbed Photosynthetically Active Radiation and Vegetation Properties in Burned Forests in Interior Alaska

    NASA Astrophysics Data System (ADS)

    Iwata, H.; Harazono, Y.; Iwama, C.; Ueyama, M.

    2011-12-01

    Wildfire is a major disturbance in boreal forest ecosystems, and it significantly influences carbon exchange processes. It is important to explicitly incorporate burned areas in estimating regional carbon dioxide (CO2) exchange. A simple approach to quantify regional CO2 exchange is an application of a light-use efficiency model with satellite data. The model calculates CO2 uptake from light-use efficiency and absorbed photosynthetically active radiation (PAR). In the regional application, the fraction of absorbed PAR (FAPAR) provided from MODIS satellite data, together with incident PAR, is often used to calculate absorbed PAR. In spite of the importance of FAPAR in estimating CO2 uptake, an earlier study revealed that the MODIS FAPAR data are overestimated for a burned boreal forest. This study aims to provide ground truth data to validate MODIS FAPAR in other burned boreal forests. It also focuses on obtaining an empirical relationship to estimate seasonal and interannual variation in FAPAR from satellite data such as the normalized difference vegetation index (NDVI) in the early stage of recovery after wildfire. We observed incident, reflected, and transmitted PAR to obtain FAPAR in one- and six-year-old burned black spruce forests. Vegetation properties such as NDVI, leaf area index (LAI), and vegetation cover were also observed to explain seasonal variation of FAPAR. CO2 flux was also continuously monitored using the eddy covariance technique. The analysis showed that MODIS FAPAR was overestimated in the two burned forests, and the degree of overestimation was especially large for the younger burned forest. The relationship between FAPAR and NDVI was similar at the two burned forests, implying that this single relationship can be applied to estimate FAPAR from MODIS NDVI regardless of age after wildfire for the early stage of recovery.

  7. Wavenumber dependent investigation of the terrestrial infrared radiation budget with two versions of the LOWTRAN5 band model

    NASA Technical Reports Server (NTRS)

    Charlock, T. P.

    1984-01-01

    Two versions of the LOWTRAN5 radiance code are used in a study of the earth's clear sky infrared radiation budget in the interval 30 per cm (333.3 microns) to 3530 per cm (2.8 microns). One version uses 5 per cm resolution and temperature dependent molecular absorption coefficients, and the second uses 20 per cm resolution and temperature independent molecular absorption coefficients. Both versions compare well with Nimbus 3 IRIS spectra, with some discrepancies at particular wavenumber intervals. Up and downgoing fluxes, calculated as functions of latitude, are displayed for wavenumbers at which the principle absorbers are active. Most of the variation of the fluxes with latitude is found in the higher wavenumber intervals for both clear and cloudy skies. The main features of the wavenumber integrated cooling rates are explained with reference to calculations in more restricted wavenumber intervals. A tropical lower tropospheric cooling maximum is produced by water vapor continuum effects in the 760-1240 per cm window. A secondary upper tropospheric cooling maximum, with wide meridional extent, is produced by water vapor rotational lines between 30-430 per cm. Water vapor lines throughout the terrestrial infrared spectrum prevent the upflux maximum from coinciding with the surface temperature maximum.

  8. Susceptibility of various life stages of Rhyzopertha dominica (Coleoptera: Bostrichidae) to flameless catalytic infrared radiation.

    PubMed

    Khamis, Moses; Subramanyam, Bhadriraju; Flinn, Paul W; Dogan, Hulya; Jager, Abigail; Gwirtz, Jeffrey A

    2010-08-01

    In laboratory experiments, a flameless catalytic infrared emitter, fueled by propane, was used to disinfest hard red winter wheat, Triticum aestivum L., containing different life stages of the lesser grain borer, Rhyzopertha dominica (F.), an economically important insect species associated with stored wheat in Kansas. The emitter generates infrared radiation in the 3-7-microm range. The life stages of R. dominica exposed to infrared radiation included eggs, larvae in different stages of development, pupae, and 2-wk-old adults. A noncontact infrared thermometer measured grain temperatures continuously during exposures of infested wheat to infrared radiation. The grain temperatures attained were influenced by wheat quantity; distance from the emitter; and exposure time, which in turn influenced effectiveness against various life stages of H. dominica. In general, higher grain temperatures were attained in 113.5 g of wheat as opposed to 227.0 g, and at 8.0 cm from the emitter surface rather than at 12.7 cm, and during a 60-s exposure compared with a 45-s exposure. Logistic regression indicated the probability of death of various life stages of R. dominica was temperature dependent. The log odds ratios showed old larvae were less susceptible to infrared radiation than young larvae. Approximately > or = 94% mortality of all R. dominica life stages occurred when using 113.5 g of wheat, exposed for 60 s at a distance of 8.0 cm from the emitter, resulting in mean +/- SE wheat temperatures that ranged between 107.6 +/- 1.4 and 113.5 +/- 0.5 degrees C. Our results with small grain quantities show flameless catalytic infrared technology to be a promising tool for disinfestation of stored wheat.

  9. Infrared luminescence for real time ionizing radiation detection

    SciTech Connect

    Veronese, Ivan Mattia, Cristina De; Cantone, Marie Claire; Fasoli, Mauro; Chiodini, Norberto; Vedda, Anna; Mones, Eleonora

    2014-08-11

    Radio-luminescence (RL) optical fiber sensors enable a remote, punctual, and real time detection of ionizing radiation. However, the employment of such systems for monitoring extended radiation fields with energies above the Cerenkov threshold is still challenging, since a spurious luminescence, namely, the “stem effect,” is also generated in the passive fiber portion exposed to radiation. Here, we present experimental measurements on Yb-doped silica optical fibers irradiated with photon fields of different energies and sizes. The results demonstrate that the RL of Yb{sup 3+}, displaying a sharp emission line at about 975 nm, is free from any spectral superposition with the spurious luminescence. This aspect, in addition with the suitable linearity, reproducibility, and sensitivity properties of the Yb-doped fibers, paves the way to their use in applications where an efficient stem effect removal is required.

  10. A Far-infrared Undulator for Coherent Synchrotron Radiation and Free Electron Laser at Tohoku University

    NASA Astrophysics Data System (ADS)

    Hama, Hiroyuki; Hinode, Fujio; Kawai, Masayuki; Nanbu, Kenichi; Miyahara, Fusashi; Yasuda, Mafuyu

    2010-06-01

    In order to develop an intense far-infrared radiation source, a high quality electron beam has been studied at Tohoku University, Sendai. The bunch length of the beam expected is very much shorter than terahertz (THz) wavelength, so that coherent spontaneous emission of synchrotron radiation will be a promising high brilliant far-infrared source. An undulator consisting of permanent magnets has been designed in which optional free electron laser (FEL) will be operated in free space mode. Consequently the minimum gap of the undulator is decided to be 54 mm for 0.36 mm radiation to avoid diffraction loss, and then the period length of 10 cm is employed. The undulator may cover a wavelength range from 0.18 to 0.36 mm with the beam energy of 17 MeV. Property of coherent THz radiation from the undulator and possibility of novel pre-bunched THz FEL is discussed.

  11. Biophysical properties affecting vegetative canopy reflectance and absorbed photosynthetically active radiation at the FIFE site

    NASA Technical Reports Server (NTRS)

    Walter-Shea, E. A.; Blad, B. L.; Hays, C. J.; Mesarch, M. A.; Deering, D. W.; Middleton, E. M.

    1992-01-01

    Leaves of the dominant grass species of the ISCLP FIFE site reflect and transmit radiation in a like manner to other healthy green leaves. Visible reflectance factors (RFs) and transmittance factors (TFs) were less for older leaves than younger leaves except during senescence, when RF and TF values were greater. NIR-RF values increased and TF values decreased with leaf age, with the reverse occurring as the leaf went through senescence.

  12. Biophysical properties affecting vegetative canopy reflectance and absorbed photosynthetically active radiation at the FIFE site

    SciTech Connect

    Walter-shea, E.A.; Blad, B.L.; Hays, C.J.; Mesarch, M.A.; Deering, D.W.; Middleton, E.M. NASA, Goddard Space Flight Center, Greenbelt, MD )

    1992-11-01

    Leaves of the dominant grass species of the ISCLP FIFE site reflect and transmit radiation in a like manner to other healthy green leaves. Visible reflectance factors (RFs) and transmittance factors (TFs) were less for older leaves than younger leaves except during senescence, when RF and TF values were greater. NIR-RF values increased and TF values decreased with leaf age, with the reverse occurring as the leaf went through senescence. 39 refs.

  13. Interaction of laser radiation with a low-density structured absorber

    NASA Astrophysics Data System (ADS)

    Rozanov, V. B.; Barishpol'tsev, D. V.; Vergunova, G. A.; Demchenko, N. N.; Ivanov, E. M.; Aristova, E. N.; Zmitrenko, N. V.; Limpouch, I.; Ulschmidt, I.

    2016-02-01

    A theoretical model is proposed for computing simulations of laser radiation interaction with inhomogeneous foam materials doped with heavy elements and undoped materials. The model satisfactorily describes many experiments on the interaction of the first and third harmonics of a 200 J pulsed PALS iodine laser with low-density porous cellulose triacetate targets. The model can be used to analyze experimental data and estimate the reality of experimental results.

  14. Multiple myeloma among atomic bomb survivors in Hiroshima and Nagasaki, 1950-76: relationship to radiation dose absorbed by marrow

    SciTech Connect

    Ichimaru, M.; Ishimaru, T.; Mikami, M.; Matsunaga, M.

    1982-08-01

    The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimated risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure.

  15. Multiple myeloma among atomic bomb survivors in Hiroshima and Nagasaki, 1950-76: relationship to radiation dose absorbed by marrow

    SciTech Connect

    Ichimaru, M.; Ishimaru, T.; Mikami, M.; Matsunaga, M.

    1982-08-01

    The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimaged risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure.

  16. Force, torque, and absorbed energy for a body of arbitrary shape and constitution in an electromagnetic radiation field

    NASA Astrophysics Data System (ADS)

    Farsund, Ø.; Felderhof, B. U.

    1996-02-01

    The force and torque exerted on a body of arbitrary shape and constitution by a stationary radiation field are in principle given by integrals of Minkowski's stress tensor over a surface surrounding the body. Similarly the absorbed energy is given by an integral of the Poynting vector. These integrals are notoriously difficult to evaluate, and so far only spherical bodies have been considered. It is shown here that the integrals may be cast into a simpler form by use of Debye potentials. General expressions for the integrals are derived as sums of bilinear expressions in the coefficients of the expansion of the incident and scattered waves in terms of vector spherical waves. The expressions are simplified for small particles, such as atoms, for which the electric dipole approximation may be used. It is shown that the calculation is also relevant for bodies with nonlinear electromagnetic response.

  17. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: III. Galactic far-infrared radiation

    NASA Astrophysics Data System (ADS)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2015-07-01

    Using the three-component spectral model describing the FIRAS average continuum spectra, the exact analytical expressions for thermodynamic and radiative functions of Galactic far-infrared radiation are obtained. The COBE FIRAS instrument data in the 0.15-2.88 THz frequency interval at the mean temperatures of T1 = 17.72 K, T2 = 14 K and T3 = 6.73 K are used for calculating the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, total emissivity, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume and pressure for the warm, intermediate-temperature and very cold components of the Galactic continuum spectra. The generalized Stefan-Boltzmann law for warm, intermediate-temperature and very cold components is constructed. The temperature dependence of each component is determined by the formula IS-B(T) = σ‧T6. This result is important when we construct the cosmological models of radiative transfer that can be applied inside the Galaxy. Within the framework of the three-component spectral model, the total number of photons in our Galaxy and the total radiation power (total luminosity) emitted from a surface of the Galaxy are calculated. Their values are NGtotal = 1.3780 × 1068 and IGtotal(T) = 1.0482 × 1036 W. Other radiative and thermodynamic properties of the Galactic far-infrared radiation (photon gas) of the Galaxy are calculated. The expressions for astrophysical parameters, such as the entropy density/Boltzmann constant and number density of the Galactic far-infrared photons are obtained. We assume that the obtained analytical expressions for thermodynamic and radiative functions may be useful for describing the continuum spectra of the far-infrared radiation for other galaxies.

  18. The Effects of an Absorbing Smoke Layer on MODIS Marine Boundary Layer Cloud Optical Property Retrievals and Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Meyer, Kerry; Platnick, Steven

    2012-01-01

    Clouds, aerosols, and their interactions are widely considered to be key uncertainty components in our current understanding of the Earth's atmosphere and radiation budget. The work presented here is focused on the quasi-permanent marine boundary layer . (MBL) clouds off the southern Atlantic coast of Africa and the effects on MODIS cloud optical property retrievals (MOD06) of an overlying absorbing smoke layer. During much of August and September, a persistent smoke layer resides over this region, produced from extensive biomass burning throughout the southern African savanna. The resulting absorption, which increases with decreasing wavelength, potentially introduces biases into the MODIS cloud optical property retrievals of the underlying MBL clouds. This effect is more pronounced in the cloud optical thickness retrievals, which over ocean are derived from the wavelength channel centered near 0.86 micron (effective particle size retrievals are derived from the longer-wavelength near-IR channels at 1.6, 2.1, and 3.7 microns). Here, the spatial distributions of the scalar statistics of both the cloud and aerosol layers are first determined from the CALIOP 5 km layer products. Next, the MOD06 look-up tables (LUTs) are adjusted by inserting an absorbing smoke layer of varying optical thickness over the cloud. Retrievals are subsequently performed for a subset of MODIS pixels collocated with the CALIOP ground track, using smoke optical thickness from the CALIOP 5km aerosol layer product to select the appropriate LUT. The resulting differences in cloud optical property retrievals due to the inclusion of the smoke layer in the LUTs will be examined. In addition, the direct radiative forcing of this smoke layer will be investigated from the perspective of the cloud optical property retrieval differences.

  19. Effect of low-intensity infrared and millimeter radiation on higher plants' biopotentials.

    PubMed

    Mironova, E A; Romanovskii, Y M

    2001-01-01

    This article studies the effect of local low-intensity electromagnetic radiation on the bioelectric responses of plants. In our investigation, we used thirty-three wavelengths in the visible and infrared spectrurm regions as well as three wavelengths in the millimeter spectrum region. As a result, we obtained the bioelectric responses of plants to electromagnetic radiation not only in the absorption region of cellular pigments (such as chlorophyll, flavin, and phytochrome) but also in the absorption region of water molecules.

  20. Relative Efficiency of TLD-100 to Linear Energy Transfer Radiation: Correction to Astronaut Absorbed Dose

    NASA Technical Reports Server (NTRS)

    Badhwar, Gautam D.; Cash, B. L.; Semones, E. J.; Yasuda, H.; Fujitaka, K.

    1999-01-01

    Response of thermoluminescent detectors (TLD-100) to high linear energy transfer (LET) particles has been studied using helium, carbon, silicon, and iron ions from the Heavy Ion Medical Accelerator at Chiba (Japan), iron ions from the Brookhaven National Laboratory (NY) Alternate Gradient Synchrotron, and 53, 134, 185, and 232 MeV protons from the Loma Linda accelerator. Using the measured relative (to (137)Cs dose efficiency, and measured LET spectra from a tissue equivalent proportional counter (TEPC) on 20 Space Shuttle flights, and 7 Mir flights, the underestimation of absorbed dose by these detectors has been evaluated. The dose underestimation is between 15-20% depending upon the flight inclination and shielding location. This has been confirmed by direct correlation of measured dose by TEPC and TLD-100 at a low shielded location in the Shuttle mid-deck. A comparison of efficiency- LET data with a compilation of similar data from TLD-700, shows that shapes of the two curves are nearly identical, but that the TLD-100 curve is systematically lower by about 13%, and is the major cause of dose underestimation. These results strongly suggest that TLDs used for crew dose estimation be regularly calibrated using heavy ions.

  1. Relative Efficiency of TLD-100 to High Linear Energy Transfer Radiation: Correction to Astronaut Absorbed Dose

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Cash, B. L.; Semones, E. J.; Yasuda, H.; Fujitaka, K.

    1999-01-01

    Response of thermoluminescent detectors (TLD-100) to high linear energy transfer (LET) particles has been studied using helium, carbon, silicon, and iron ions from the Heavy Ion Medical Accelerator at Chiba (Japan), iron ions from the Brookhaven National Laboratory (NY) Alternate Gradient Synchrotron, and 53, 134, 185, and 232 MeV protons from the Loma Linda accelerator. Using the measured relative (to 137Cs) dose efficiency, and measured LET spectra from a tissue equivalent proportional counter (TEPC) on 20 Space Shuttle flights, and 7 Mir flights, the underestimation of absorbed dose by these detectors has been evaluated. The dose underestimation is between 15-20% depending upon the flight inclination and shielding location. This has been confirmed by direct correlation of measured dose by TEPC and TLD-100 at a low shielded location in the Shuttle mid-deck. A comparison of efficiency- LET data with a compilation of similar data from TLD-700, shows that shapes of the two curves are nearly identical, but that the TLD-100 curve is systematically lower by about 13%, and is the major cause of dose underestimation. These results strongly suggest that TLDs used for crew dose estimation be regularly calibrated using heavy ions.

  2. Infrared Radiography: Modeling X-ray Imaging without Harmful Radiation

    ERIC Educational Resources Information Center

    Zietz, Otto; Mylott, Elliot; Widenhorn, Ralf

    2015-01-01

    Planar x-ray imaging is a ubiquitous diagnostic tool and is routinely performed to diagnose conditions as varied as bone fractures and pneumonia. The underlying principle is that the varying attenuation coefficients of air, water, tissue, bone, or metal implants within the body result in non-uniform transmission of x-ray radiation. Through the…

  3. Assessment of tissue heating under tunable near-infrared radiation.

    PubMed

    Bixler, Joel N; Hokr, Brett H; Denton, Michael L; Noojin, Gary D; Shingledecker, Aurora D; Beier, Hope T; Thomas, Robert J; Rockwell, Benjamin A; Yakovlev, Vladislav V

    2014-01-01

    The time-temperature effects of laser radiation exposure are investigated as a function of wavelength. Here, we report the thermal response of bulk tissue as a function of wavelength from 700 to 1064 nm. Additionally, Monte Carlo simulations were used to verify the thermal response measured and predict damage thresholds based on the response.

  4. IPR 1.0: an efficient method for calculating solar radiation absorbed by individual plants in sparse heterogeneous woody plant communities

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Chen, W.; Li, J.

    2013-12-01

    Climate change may alter the spatial distribution, composition, structure, and functions of plant communities. Transitional zones between biomes, or ecotones, are particularly sensitive to climate change. Ecotones are usually heterogeneous with sparse trees. The dynamics of ecotones are mainly determined by the growth and competition of individual plants in the communities. Therefore it is necessary to calculate solar radiation absorbed by individual plants for understanding and predicting their responses to climate change. In this study, we developed an individual plant radiation model, IPR (version 1.0), to calculate solar radiation absorbed by individual plants in sparse heterogeneous woody plant communities. The model is developed based on geometrical optical relationships assuming crowns of woody plants are rectangular boxes with uniform leaf area density. The model calculates the fractions of sunlit and shaded leaf classes and the solar radiation absorbed by each class, including direct radiation from the sun, diffuse radiation from the sky, and scattered radiation from the plant community. The solar radiation received on the ground is also calculated. We tested the model by comparing with the analytical solutions of random distributions of plants. The tests show that the model results are very close to the averages of the random distributions. This model is efficient in computation, and is suitable for ecological models to simulate long-term transient responses of plant communities to climate change.

  5. Polarization of far-infrared radiation from molecular clouds

    NASA Technical Reports Server (NTRS)

    Novak, G.; Gonatas, D. P.; Hildebrand, R. H.; Platt, S. R.; Dragovan, M.

    1989-01-01

    The paper reports measurements of the polarization of far-infrared emission from dust in nine molecular clouds. Detections were obtained in Mon R2, in the Kleinmann-Low (KL) nebula in Orion, and in Sgr A. Upper limits were set for six other clouds. A comparison of the 100 micron polarization of KL with that previously measured at 270 microns provides new evidence that the polarization is due to emission from magnetically aligned dust grains. Comparing the results for Orion with measurements at optical wavelengths, it is inferred that the magnetic field direction in the outer parts of the Orion cloud is the same as that in the dense core. This direction is nearly perpendicular to the ridge of molecular emission and is parallel to both the molecular outflow in KL and the axis of rotation of the cloud core. In Mon R2, the field direction which the measurements imply does not agree withthat derived from 0.9-2.2 micron polarimetry. The discrepancy is attributed to scattering in the near-infrared. In Orion and Sgr A, where comparisons are possible, the measurements are in good agreement with 10 micron polarization measurements.

  6. Non-LTE diagnositics of infrared radiation of Titan's atmosphere

    NASA Astrophysics Data System (ADS)

    Feofilov, Artem; Rezac, Ladislav; Kutepov, Alexander; Vinatier, Sandrine; Rey, Michael; Nikitin, Andrew; Tyuterev, Vladimir

    2016-06-01

    Yelle (1991) and Garcia-Comas et al, (2011) demonstrated the importance of accounting for the local thermodynamic equilibrium (LTE) breakdown in the middle and upper atmosphere of Titan for the interpretation of infrared radiances measured at these heights. In this work, we make further advance in this field by: • updating the non-LTE model of CH4 emissions in Titan's atmosphere and including a new extended database of CH4 spectroscopic parameters • studying the non-LTE CH4 vibrational level populations and the impact of non-LTE on limb infrared emissions of various CH4 ro-vibrational bands including those at 7.6 and 3.3 µm • implementing our non-LTE model into the LTE-based retrieval algorithm applied by Vinatier et al., (2015) for processing the Cassini/CIRS spectra. We demonstrate that accounting for non-LTE leads to an increase in temperatures retrieved from CIRS 7.6 µm limb emissions spectra (˜10 K at 600 km altitude) and estimate how this affects the trace gas density retrieval. Finally, we discuss the effects of including a large number of weak one-quantum and combinational bands on the calculated daytime limb 3.3 µm emissions and the impact they may have on the CH4 density retrievals from the Cassini VIMS 3.3 µm limb emission observations.

  7. Estimating scattered and absorbed radiation in plant canopies by remote sensing

    NASA Technical Reports Server (NTRS)

    Daughtry, G. S. T.; Ranson, K. J.

    1987-01-01

    Several research avenues are summarized. The relationships of canopy characteristics to multispectral reflectance factors of vegetation are reviewed. Several alternative approaches for incorporating spectrally derived information into plant models are discussed, using corn as the main example. A method is described and evaluated whereby a leaf area index is estimated from measurements of radiation transmitted through plant canopies, using soybeans as an example. Albedo of a big bluestem grass canopy is estimated from 60 directional reflectance factor measurements. Effects of estimating albedo with substantially smaller subsets of data are evaluated.

  8. Tumoral fibrosis effect on the radiation absorbed dose of (177)Lu-Tyr(3)-octreotate and (177)Lu-Tyr(3)-octreotate conjugated to gold nanoparticles.

    PubMed

    Azorín-Vega, E P; Zambrano-Ramírez, O D; Rojas-Calderón, E L; Ocampo-García, B E; Ferro-Flores, G

    2015-06-01

    The aim of this work was to evaluate the tumoral fibrosis effect on the radiation absorbed dose of the radiopharmaceuticals (177)Lu-Tyr(3)-octreotate (monomeric) and (177)Lu-Tyr(3)-octreotate-gold nanoparticles (multimeric) using an experimental HeLa cells tumoral model and the Monte Carlo PENELOPE code. Experimental and computer micro-environment models with or without fibrosis were constructed. Results showed that fibrosis increases up to 33% the tumor radiation absorbed dose, although the major effect on the dose was produced by the type of radiopharmaceutical (112Gy-multimeric vs. 43Gy-monomeric).

  9. Tumoral fibrosis effect on the radiation absorbed dose of (177)Lu-Tyr(3)-octreotate and (177)Lu-Tyr(3)-octreotate conjugated to gold nanoparticles.

    PubMed

    Azorín-Vega, E P; Zambrano-Ramírez, O D; Rojas-Calderón, E L; Ocampo-García, B E; Ferro-Flores, G

    2015-06-01

    The aim of this work was to evaluate the tumoral fibrosis effect on the radiation absorbed dose of the radiopharmaceuticals (177)Lu-Tyr(3)-octreotate (monomeric) and (177)Lu-Tyr(3)-octreotate-gold nanoparticles (multimeric) using an experimental HeLa cells tumoral model and the Monte Carlo PENELOPE code. Experimental and computer micro-environment models with or without fibrosis were constructed. Results showed that fibrosis increases up to 33% the tumor radiation absorbed dose, although the major effect on the dose was produced by the type of radiopharmaceutical (112Gy-multimeric vs. 43Gy-monomeric). PMID:25305748

  10. Absorbed dose measurements for kV-cone beam computed tomography in image-guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Hioki, Kazunari; Araki, Fujio; Ohno, Takeshi; Nakaguchi, Yuji; Tomiyama, Yuuki

    2014-12-01

    In this study, we develope a novel method to directly evaluate an absorbed dose-to-water for kilovoltage-cone beam computed tomography (kV-CBCT) in image-guided radiation therapy (IGRT). Absorbed doses for the kV-CBCT systems of the Varian On-Board Imager (OBI) and the Elekta X-ray Volumetric Imager (XVI) were measured by a Farmer ionization chamber with a 60Co calibration factor. The chamber measurements were performed at the center and four peripheral points in body-type (30 cm diameter and 51 cm length) and head-type (16 cm diameter and 33 cm length) cylindrical water phantoms. The measured ionization was converted to the absorbed dose-to-water by using a 60Co calibration factor and a Monte Carlo (MC)-calculated beam quality conversion factor, kQ, for 60Co to kV-CBCT. The irradiation for OBI and XVI was performed with pelvis and head modes for the body- and the head-type phantoms, respectively. In addition, the dose distributions in the phantom for both kV-CBCT systems were calculated with MC method and were compared with measured values. The MC-calculated doses were calibrated at the center in the water phantom and compared with measured doses at four peripheral points. The measured absorbed doses at the center in the body-type phantom were 1.96 cGy for OBI and 0.83 cGy for XVI. The peripheral doses were 2.36-2.90 cGy for OBI and 0.83-1.06 cGy for XVI. The doses for XVI were lower up to approximately one-third of those for OBI. Similarly, the measured doses at the center in the head-type phantom were 0.48 cGy for OBI and 0.21 cGy for XVI. The peripheral doses were 0.26-0.66 cGy for OBI and 0.16-0.30 cGy for XVI. The calculated peripheral doses agreed within 3% in the pelvis mode and within 4% in the head mode with measured doses for both kV-CBCT systems. In addition, the absorbed dose determined in this study was approximately 4% lower than that in TG-61 but the absorbed dose by both methods was in agreement within their combined

  11. Production of C-Fe-Pd nanocomposites via Infra-red radiation and its structural characterization

    NASA Astrophysics Data System (ADS)

    Kovtun, A. V.; Dzidziguri, E. L.; Muratov, D. G.

    2016-08-01

    The objective of the present study is to produce C-Fe-Pd nanocomposites using pyrolyzed infrared (IR) radiation. The structural characterization was analyzed using X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray fluorescence analysis. In addition, the size of metal nanocomposites as a function of the pyrolysis temperature, and its distribution within the carbon matrix is also characterized.

  12. Moisture removal characteristics of thin layer rough rice under sequenced infrared radiation heating and cooling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice drying with infrared (IR) radiation has been investigated during recent years and showed promising potential with improved quality and energy efficiency. The objective of this study was to further investigate the moisture removal characteristics of thin layer rough rice heated by IR and cooled ...

  13. Drying Characteristics and Quality of Rough Rice Under Infrared Radiation Heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infrared (IR) radiation heating could provide high heating rate and rapid moisture removal for rough rice drying. The objective of this research was to investigate the effect of drying bed thickness on drying characteristics and quality of rough rice under IR heating. The samples of freshly harves...

  14. Drying characteristics and quality of rough rice under infrared radiation heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infrared (IR) radiation heating could provide high heating rate and rapid moisture removal for rough rice drying. The objective of this research was to investigate the effect of the drying bed thickness on drying characteristics and quality of rough rice subjected to IR heating. Samples of freshly ...

  15. High Resolution Infrared Radiation Sounder (HIRS) for the Nimbus F Spacecraft

    NASA Technical Reports Server (NTRS)

    Koenig, E. W.

    1975-01-01

    Flown on Nimbus F in June 1975, the high resolution infrared radiation sounder (HIRS) scans with a geographical resolution of 23KM and samples radiance in seventeen selected spectral channels from visible (.7 micron) to far IR (15 micron). Vertical temperature profiles and atmospheric moisture content can be inferred from the output. System operation and test results are described.

  16. Effect of chlorofluoromethane infrared radiation on zonal atmospheric temperatures

    NASA Technical Reports Server (NTRS)

    Dickinson, R. E.; Donahue, T. M.; Liu, S. C.

    1978-01-01

    Estimates are made of changes in the atmospheric climate due to the radiative effects of 10 ppb of chlorofluoromethanes (CFM's). The estimates are derived on the basis of a 12-layer stratospheric general circulation model with a specified change of ocean temperature. Two tropical maxima in zonal average temperature change were observed: one in the upper troposphere and one centered at the tropopause. The temperature change exceeds the surface temperature change by a factor of at least two. If the 1975 CFM emission rate were to continue indefinitely, stratospheric water-vapor concentrations would increase by up to 60% due to CFM radiative effects. This would reduce ozone concentrations by an additional 4% of the natural ozone column.

  17. Mapping the infrared background radiation from the Shuttle

    NASA Technical Reports Server (NTRS)

    Koch, D.; Fazio, G. G.; Traub, W. A.; Urban, E. W.; Katz, L.; Rieke, G. H.; Gautier, T. N.; Hoffmann, W. F.; Low, F. J.; Poteet, W.

    1981-01-01

    The Spacelab-2 Small Helium-Cooled Infrared Telescope will be used to map extended astronomical sources of low surface brightness emission, to measure the Shuttle induced environment and to develop techniques for managing large volumes of superfluid helium in space. The instrument is an f/4 15.2-cm Herschelian telescope with ten photoconductor detectors in the focal plane. This paper describes the hardware and software aspects of the instrument with emphasis on mission operations. In particular, a description is given of the observing plan formulated to meet the scientific and engineering objectives, the scan drive system, the precautions in design and operation necessary to prevent the sun, moon, and earth from adversely affecting the observations, the implications of thruster firings, and the on-board experiment computer application software to control the scanning of the telescope and support on-board displays.

  18. A perturbative treatment of aerosol scattering of infrared radiation

    NASA Technical Reports Server (NTRS)

    Yueh, W. R.; Chameides, W. L.

    1979-01-01

    Calculations of long-wave atmospheric heating and cooling rates using the rate equations of Rodgers and Walshaw (1966) with the Malkmus (1967) random band model are presented. A perturbation scheme is developed for the inclusion of aerosol scattering effects in the numerical calculation. Unlike the flux differencing method for calculating long-wave heating and cooling rates, this scheme allows aerosol effects to be included in a simple manner with only a small additional use of computer time. The calculations indicate good agreement with those of previous investigators and demonstrate the expected equivalence of the flux-differencing method and the flux-divergence equation of Rodgers and Walshaw (1966), even at stratospheric altitudes. It is found that aerosols lead to a net heating in the lower troposphere due to infrared scattering and absorption.

  19. Resonant infrared detector with substantially unit quantum efficiency

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam (Inventor); Mcmurray, Robert E., Jr. (Inventor)

    1994-01-01

    A resonant infrared detector includes an infrared-active layer which has first and second parallel faces and which absorbs radiation of a given wavelength. The detector also includes a first tuned reflective layer, disposed opposite the first face of the infrared-active layer, which reflects a specific portion of the radiation incident thereon and allows a specific portion of the incident radiation at the given wavelength to reach the infrared-active layer. A second reflective layer, disposed opposite the second face of the infrared-active layer, reflects back into the infrared-active layer substantially all of the radiation at the given wavelength which passes through the infrared-active layer. The reflective layers have the effect of increasing the quantum efficiency of the infrared detector relative to the quantum efficiency of the infrared-active layer alone.

  20. Formation of gold branched plates in diluted solutions of poly(vinylpyrrolidone) and their use for the fabrication of near-infrared-absorbing films and coatings.

    PubMed

    Pardiñas-Blanco, Iván; Hoppe, Cristina E; Piñeiro-Redondo, Yolanda; López-Quintela, M Arturo; Rivas, José

    2008-02-01

    Ribbon-like and branched gold nano- and microstructures were produced by simple heating of diluted aqueous solutions of poly(vinylpyrrolidone) (PVP) and HAuCl4. The reaction was carried out in a one-pot, one-step process at mild temperatures. Modification of the synthesis variables allowed the obtaining of structures with different sizes and branching degrees which formed stable hydrosols with characteristic colors. A mechanism for the growth of the crystals was proposed, based on the aggregation of metal units followed by reorientation and attachment processes facilitated by the presence of low concentrations of the polymer. These anisotropic structures were used to obtain large-area porous coatings on metallic, plastic, and glass substrates and to synthesize homogeneous polymer composites. The resulting gold-modified materials showed an important increase of absorption in the near-infrared (NIR) region of the electromagnetic spectrum, which could find interesting applications in the development of NIR-absorbing filters and coatings.

  1. Thermal imaging method to visualize a hidden painting thermally excited by far infrared radiations

    NASA Astrophysics Data System (ADS)

    Davin, T.; Wang, X.; Chabane, A.; Pawelko, R.; Guida, G.; Serio, B.; Hervé, P.

    2015-06-01

    The diagnosis of hidden painting is a major issue for cultural heritage. In this paper, a non-destructive active infrared thermographic technique was considered to reveal paintings covered by a lime layer. An extended infrared spectral range radiation was used as the excitation source. The external long wave infrared energy source delivered to the surface is then propagated through the material until it encounters a painting zone. Due to several thermal effects, the sample surface then presents non-uniformity patterns. Using a high sensitive infrared camera, the presence of covered pigments can thus be highlighted by the analysis of the non-stationary phenomena. Reconstituted thermal contrast images of mural samples covered by a lime layer are shown.

  2. Effects of ozone and UV-B radiation on growth, UV-B absorbing pigments, and antioxidants in soybean

    SciTech Connect

    Miller, J.E. North Carolina State Univ., Raleigh ); Pursley, W.A. )

    1990-05-01

    Depletion of stratospheric ozone is projected to cause increased UV-B radiation at the earth's surface. Some research suggests that increased UV-B radiation may be detrimental to crop growth. Current levels of ozone in the troposphere are known to suppress plant growth. Since these two stresses occur concurrently, field experiments were performed to determine their separate and combined effects on growth and physiological responses of soybean. Ozone treatments were controlled with open-top chambers, and UV-B treatments were administered with filtered lamps. Ozone (0.06 ppm mean 12-hr per day concentration during the 6 wk growth period) significantly suppressed biomass of leaves, stems, and roots throughout vegetative and early reproductive growth compared to controls receiving 0.025 ppm ozone. While plant biomass was often slightly less in elevated UV-B treatments (treatments approximating 25 to 28% depletion of stratospheric ozone), results usually were not significant. Significant interactions of ozone and UV-B usually reflected less than additive response of biomass to the two stresses in combination. Glutathione content and glutathione reductase activity were reduced by UV-B but increased by ozone. Ascorbate and UV-B absorbing pigments were increased by UV-B and unaffected by ozone. No consistent interactions of ozone and UV-B on these components were found.

  3. Determination of absorbed dose in high-energy electron and photon radiation by means of an uncalibrated ionization chamber.

    PubMed

    Klevenhagen, S C

    1991-02-01

    The aim of this study was to develop a dosimetric method based on an ionization chamber which has an uncalibrated sensitive volume but which behaves as a Bragg-Gray cavity in high-energy radiation. The new type of chamber developed in the course of this study has a variable volume and is constructed from water-similar materials. It can be used in a water phantom directly in a beam of a therapy megavoltage machine under clinical conditions. The chamber allows absorbed dose to be determined from first principles, overcoming many of the problems encountered with conventional dosimetry based on calibrated chambers. The study involved an intercomparison of the performance of the new chamber in high-energy electron and photon radiation with the conventional calibrated chambers employed according to the established dosimetry protocols. Good agreement was found between these dosimetric methods and it may therefore be concluded that the method developed in this work can be successfully employed for absolute dosimetry. The new chamber is a promising device for research in various aspects of dosimetry.

  4. AGN Obscuration Through Dusty Infrared Dominated Flows. 1; Radiation-Hydrodynamics Solution for the Wind

    NASA Technical Reports Server (NTRS)

    Dorodnitsyn, A.; Bisnovatyi-Kogan. G. S.; Kallman, T.

    2011-01-01

    We construct a radiation-hydrodynamics model for the obscuring toroidal structure in active galactic nuclei. In this model the obscuration is produced at parsec scale by a dense, dusty wind which is supported by infrared radiation pressure on dust grains. To find the distribution of radiation pressure, we numerically solve the 2D radiation transfer problem in a flux limited diffusion approximation. We iteratively couple the solution with calculations of stationary 1D models for the wind, and obtain the z-component of the velocity. Our results demonstrate that for AGN luminosities greater than 0.1 L(sub edd) external illumination can support a geometrically thick obscuration via outflows driven by infrared radiation pressure. The terminal velocity of marginally Compton-thin models (0.2 < tau(sub T) < 0.6), is comparable to or greater than the escape velocity. In Compton thick models the maximum value of the vertical component of the velocity is lower than the escape velocity, suggesting that a significant part of our torus is in the form of failed wind. The results demonstrate that obscuration via normal or failed infrared-driven winds is a viable option for the AGN torus problem and AGN unification models. Such winds can also provide an important channel for AGN feedback.

  5. Infrared radiation emerging from smoke produced by brush fires

    NASA Technical Reports Server (NTRS)

    Weinman, J. A.; Olson, W. S.; Harshvardhan, M.

    1981-01-01

    The IR radiative transport properties of brush fire smoke clouds, computed for a model with finite horizontal dimensions as well as the more common plane-parallel model, are presented. The finite model is a three-dimensional version of the two-stream approximation applied to cubic clouds of steam, carbon, and silicates. Assumptions are made with regard to the shape and size distributions of the smoke particles. It is shown that 11.5-micron radiometry can detect fires beneath smoke clouds if the path integrated mass density of the smoke is less than or equal to 3 g/sq m.

  6. Infrared radiation emerging from smoke produced by brush fires.

    PubMed

    Weinman, J A; Harshvardhan, H; Olson, W S

    1981-01-15

    This study presents the IR radiative transport properties of brush fire smoke clouds computed for a model with finite horizontal dimensions as well as the more common plane-parallel model. The finite model is a 3-D version of the two-stream approximation applied to cubic clouds of steam, carbon, and silicates. Assumptions are made with regard to the shape and size distributions of the smoke particles. It is shown that 11.5-microm radiometry can detect fires beneath smoke clouds if the path integrated mass density of the smoke is less, similar3 g/m(2).

  7. Efficient far-infrared thermal bremsstrahlung radiation from a heterojunction bipolar transistor

    SciTech Connect

    Chung, Pei-Kang; Yen, Shun-Tung

    2015-08-28

    We investigate the far-infrared thermal radiation properties of a heterojunction bipolar transistor. The device conveniently provides a high electric field for electrons to heat the lattice and the electron gas in a background with ions embedded. Because of very high effective temperature of the electron gas in the collector, the electron-ion bremsstrahlung makes efficient the thermal radiation in the far-infrared region. The transistor can yield a radiation power of 0.1 mW with the spectral region between 2 and 75 THz and a power conversion efficiency of 6 × 10{sup −4}. Such output contains a power of 20 μW in the low-frequency part (2–20 THz) of the spectrum.

  8. Absorbed Radiation Dose in Radiosensitive Organs Using 64- and 320-Row Multidetector Computed Tomography: A Comparative Study

    PubMed Central

    Khan, Atif N.; Nikolic, Boris; Khan, Mohammad K.; Kang, Jian; Khosa, Faisal

    2014-01-01

    Aim. To determine absorbed radiation dose (ARD) in radiosensitive organs during prospective and full phase dose modulation using ECG-gated MDCTA scanner under 64- and 320-row detector modes. Methods. Female phantom was used to measure organ radiation dose. Five DP-3 radiation detectors were used to measure ARD to lungs, breast, and thyroid using the Aquilion ONE scanner in 64- and 320-row modes using both prospective and dose modulation in full phase acquisition. Five measurements were made using three tube voltages: 100, 120, and 135 kVp at 400 mA at heart rate (HR) of 60 and 75 bpm for each protocol. Mean acquisition was recorded in milligrays (mGy). Results. Mean ARD was less for 320-row versus 64-row mode for each imaging protocol. Prospective EKG-gated imaging protocol resulted in a statistically lower ARD using 320-row versus 64-row modes for midbreast (6.728 versus 19.687 mGy, P < 0.001), lung (6.102 versus 21.841 mGy, P < 0.001), and thyroid gland (0.208 versus 0.913 mGy; P < 0.001). Retrospective imaging using 320- versus 64-row modes showed lower ARD for midbreast (10.839 versus 43.169 mGy, P < 0.001), lung (8.848 versus 47.877 mGy, P < 0.001), and thyroid gland (0.057 versus 2.091 mGy; P < 0.001). ARD reduction was observed at lower kVp and heart rate. Conclusions. Dose reduction to radiosensitive organs is achieved using 320-row compared to 64-row modes for both prospective and retrospective gating, whereas 64-row mode is equivalent to the same model 64-row MDCT scanner. PMID:25170427

  9. The development of early pediatric models and their application to radiation absorbed dose calculations

    SciTech Connect

    Poston, J.W.

    1989-12-31

    This presentation will review and describe the development of pediatric phantoms for use in radiation dose calculations . The development of pediatric models for dose calculations essentially paralleled that of the adult. In fact, Snyder and Fisher at the Oak Ridge National Laboratory reported on a series of phantoms for such calculations in 1966 about two years before the first MIRD publication on the adult human phantom. These phantoms, for a newborn, one-, five-, ten-, and fifteen-year old, were derived from the adult phantom. The ``pediatric`` models were obtained through a series of transformations applied to the major dimensions of the adult, which were specified in a Cartesian coordinate system. These phantoms suffered from the fact that no real consideration was given to the influence of these mathematical transformations on the actual organ sizes in the other models nor to the relation of the resulting organ masses to those in humans of the particular age. Later, an extensive effort was invested in designing ``individual`` pediatric phantoms for each age based upon a careful review of the literature. Unfortunately, the phantoms had limited use and only a small number of calculations were made available to the user community. Examples of the phantoms, their typical dimensions, common weaknesses, etc. will be discussed.

  10. The development of early pediatric models and their application to radiation absorbed dose calculations

    SciTech Connect

    Poston, J.W.

    1989-01-01

    This presentation will review and describe the development of pediatric phantoms for use in radiation dose calculations . The development of pediatric models for dose calculations essentially paralleled that of the adult. In fact, Snyder and Fisher at the Oak Ridge National Laboratory reported on a series of phantoms for such calculations in 1966 about two years before the first MIRD publication on the adult human phantom. These phantoms, for a newborn, one-, five-, ten-, and fifteen-year old, were derived from the adult phantom. The pediatric'' models were obtained through a series of transformations applied to the major dimensions of the adult, which were specified in a Cartesian coordinate system. These phantoms suffered from the fact that no real consideration was given to the influence of these mathematical transformations on the actual organ sizes in the other models nor to the relation of the resulting organ masses to those in humans of the particular age. Later, an extensive effort was invested in designing individual'' pediatric phantoms for each age based upon a careful review of the literature. Unfortunately, the phantoms had limited use and only a small number of calculations were made available to the user community. Examples of the phantoms, their typical dimensions, common weaknesses, etc. will be discussed.

  11. Spatial variations in natural background radiation: absorbed dose rates in air in Colorado.

    PubMed

    Stone, J M; Whicker, R D; Ibrahim, S A; Whicker, F W

    1999-05-01

    Large and small-scale spatial variations in natural ambient background radiation dose rates in Colorado were investigated at 1,150 specific locations with particular attention to 40 of the more populated areas along the Front Range of the Rocky Mountains. Total dose rates (including cosmic and terrestrial components) in Front Range communities below 2,000 m elevation averaged 135 nGy h(-1). Terrestrial dose rates had a coefficient of variation of 17%. Communities above 2,000 m had a mean total dose rate of 196 nGy h(-1), and a terrestrial dose rate coefficient of variation of 17%. Across all Front Range communities, the coefficient of variation for terrestrial dose rates was 22%. Within individual communities, coefficient of variation values for terrestrial dose rates ranged from 3 to 21%. Smaller-scale spatial variability (to within a few meters) was relatively small (coefficient of variation values generally ranged from 3 to 7%). A significant linear relationship (r2 = 0.83) between the size of area surveyed (km2) and coefficient of variation value for terrestrial dose rates was found. West of the Continental Divide, the terrestrial component accounted for roughly 60% of total measured dose rates, while east of the Continental Divide, where enriched granitic source rocks and associated soils are prevalent, the terrestrial component generally accounted for two-thirds or more of total dose rates. PMID:10201565

  12. Scattering matrix of infrared radiation by ice finite circular cylinders.

    PubMed

    Xu, Lisheng; Ding, Jilie; Cheng, Andrew Y S

    2002-04-20

    Scattering matrix characteristics of polydisperse, randomly oriented, small ice crystals modeled by finite circular cylinders with various ratios of the length to diameter (L/D) ratio are calculated by use of the exact T-matrix approach, with emphasis on the thermal infrared spectral region that extends from the atmospheric short-wave IR window to the far-IR wavelengths to as large as 30 microm. The observed ice crystal size distribution and the well-known power-law distribution are considered. The results of the extensive calculations show that the characteristics of scattering matrix elements of small ice circular cylinders depend strongly on wavelengths and refractive indices, particle size distributions, and the L/D ratios. The applicability of the power-law distribution and particle shapes for light scattering calculations for small ice crystals is discussed. The effects of the effective variance of size distribution on light scattering characteristics are addressed. It seems from the behavior of scattering matrix elements of small ice crystals that the combination of 25 and 3.979 microm has some advantages and potential applications for remote sensing of cirrus and other ice clouds.

  13. Thermal damage of tissue during near-infrared laser irradiation with assistance of light-absorbing dye

    NASA Astrophysics Data System (ADS)

    Gnyawali, Surya C.; Le, Kelvin; Le, Henry; Wicksted, James P.; Bartels, Kenneth E.; Liu, Hong; Chen, Yichao; Chen, Wei R.

    2008-02-01

    The selective photothermal-tissue interaction using dye enhancement has been proven to be effective in minimizing the peripheral normal tissue damage during cancer treatment. It is important that the tissue-thermal damage be analyzed and the damage rate process be estimated before the photothermal-immunotherapy for cancer treatment. In this study, we have used the EMT6 mouse tumor model for the laser-tumor treatment with a simultaneous surface temperature measurement using infrared thermography. The images acquired were processed to obtain the temperature profiles. The saturation temperature and corresponding time of irradiation from the temporal profiles were used to calculate the damage parameter using Arrhenius rate process equation. The damage parameters obtained from six mice were compared. Our results of in vivo study show that the damage analyses agree with the previous in vitro study on skins.

  14. The role of near infrared radiation in photoaging of the skin.

    PubMed

    Schroeder, Peter; Haendeler, Judith; Krutmann, Jean

    2008-07-01

    Infrared (IR) radiation is non-ionizing, electromagnetic radiation with wavelengths between 760 nm and 1 mm, which is further divided into IRA, IRB and IRC. IR accounts for more than half of the solar energy that reaches the human skin. While IRB and IRC do not penetrate deeply into the skin, more than 65% of IRA reaches the dermis. Human skin is increasingly exposed to IRA-radiation; most relevant sources are (i) natural solar radiation consisting of over 30% IRA, (ii) artificial IRA sources used for therapeutic or wellness purposes and (iii) artificial UV sources contaminated with IRA. As part of natural sunlight, IRA significantly contributes to extrinsic skin aging. This article reviews the cutaneous effects of IRA-radiation, the underlying molecular mechanisms and the available protective strategies.

  15. Ambient temperature-independent dual-band mid-infrared radiation thermometry.

    PubMed

    Lü, You; He, Xin; Wei, Zhong-Hui; Sun, Zhi-Yuan; Chang, Song-Tao

    2016-03-20

    For temperature measurements of targets at low temperatures, dual-band radiation thermometry using mid-infrared detectors has been investigated extensively. However, the accuracy is greatly affected by the reflected ambient radiation and stray radiation, which depend on the ambient temperature. To ensure measurement accuracy, an improved dual-band measurement model is established by considering the reflected ambient radiation and the stray radiation. The effect of ambient temperature fluctuation on temperature measurement is then further analyzed in detail. Experimental results of measuring a gray-body confirm that the proposed method yields high accuracy at varying ambient temperatures. This method provides a practical approach to remove the effect of ambient temperature fluctuations on temperature measurements.

  16. Method and apparatus for reducing radiation exposure through the use of infrared data transmission

    DOEpatents

    Austin, Frank S.; Hance, Albert B.

    1989-01-01

    A method and apparatus is described for transmitting information, for exae, dosimetry data from a hazardous environment such as a radioactive area to a remote relatively safe location. A radiation detector senses the radiation and generates an electrical signal which is fed as a binary coded decimal signal to an infrared transmitter having a microprocessor. The microprocessor formats the detected information into digits of data and modulates a 40 kHz oscillator, the output of which is fed to and intensity modulates one or more infrared emitting diodes. The infrared signal from the diodes is transmitted to a portable hand-held infrared receiver remote from the hazardous environment. The receiver includes an infrared sensitive diode which decodes the data and generates an electrical signal which is coupled to a microcomputer. The microcomputer synchronizes itself to the transmitter, reads the digits of data as they are received, sums the digits and compares the sum with a checksum signal generated and transmitted from the transmitter. If a match of the checksum signals exists, the received data is displayed, otherwise it is described and the receiver conditions itself for the next transmission of data.

  17. Dynamics of photoprocesses induced by femtosecond infrared radiation in free molecules and clusters of iron pentacarbonyl

    NASA Astrophysics Data System (ADS)

    Kompanets, V. O.; Lokhman, V. N.; Poydashev, D. G.; Chekalin, S. V.; Ryabov, E. A.

    2016-04-01

    The dynamics of photoprocesses induced by femtosecond infrared radiation in free Fe(CO)5 molecules and their clusters owing to the resonant excitation of vibrations of CO bonds in the 5-μm range has been studied. The technique of infrared excitation and photoionization probing (λ = 400 nm) by femtosecond pulses has been used in combination with time-of-flight mass spectrometry. It has been found that an infrared pulse selectively excites vibrations of CO bonds in free molecules, which results in a decrease in the yield of the Fe(CO)5 + molecular ion. Subsequent relaxation processes have been analyzed and the results have been interpreted. The time of the energy transfer from excited vibrations to other vibrations of the molecule owing to intramolecular relaxation has been measured. The dynamics of dissociation of [Fe(CO)5] n clusters irradiated by femtosecond infrared radiation has been studied. The time dependence of the yield of free molecules has been measured under different infrared laser excitation conditions. We have proposed a model that well describes the results of the experiment and makes it possible, in particular, to calculate the profile of variation of the temperature of clusters within the "evaporation ensemble" concept. The intramolecular and intracluster vibrational relaxation rates in [Fe(CO)5] n clusters have been estimated.

  18. Geometrical gradients in the distribution of temperature and absorbed ultraviolet radiation in ocular tissues.

    PubMed

    Sliney, David H

    2002-01-01

    The geographical variations in the incidence of age-related ocular changes such as presbyopia and cataracts and diseases such as pterygium and droplet keratopathies have led to theories pointing to sunlight, ultraviolet radiation (UVR) exposure and ambient temperature as potential etiological factors. Some epidemiological evidence also points to an association of age-related macular degeneration to sunlight exposure. The actual distribution of sunlight exposure and the determination of temperature variations of different tissues within the anterior segment of the eye are difficult to assess. Of greatest importance are the geometrical factors that influence selective UVR exposures to different segments of the lens, cornea and retina. Studies show that the temperature of the lens and cornea varies by several degrees depending upon climate, and that the incidence of nuclear cataract incidence is greater in areas of higher ambient temperature (i.e., in the tropics). Likewise, sunlight exposure to local areas of the cornea, lens and retina varies greatly in different environments. However, epidemiological studies of the influence of environmental UVR in the development of cataract, pterygium, droplet keratopathies and age-related macular degeneration have produced surprisingly inconsistent findings. The lack of consistent results is seen to be due largely to either incomplete or erroneous estimates of outdoor UV exposure dose. Geometrical factors dominate the determination of UVR exposure of the eye. The degree of lid opening limits ocular exposure to rays entering at angles near the horizon. Clouds redistribute overhead UVR to the horizon sky. Mountains, trees and building shield the eye from direct sky exposure. Most ground surfaces reflect little UVR. The result is that highest UVR exposure occurs during light overcast where the horizon is visible and ground surface reflection is high. By contrast, exposure in a high mountain valley (lower ambient temperature) with

  19. An infrared radiation routine for use in numerical atmospheric models

    NASA Technical Reports Server (NTRS)

    Chow, M.-D.; Arking, A.

    1978-01-01

    Previous methods for calculating radiative fluxes due to water vapor and CO2 absorption bands are extended to take into consideration the entire water vapor and CO2 bands, including e-type absorption in the window region and the overlapping of different absorptions. Cooling rate profiles in the water vapor bands for a tropical atmosphere were computed by a detailed line-by-line method and by a far-wing approximation method, and the error of both methods is less than 0.2 C/day. Cooling rate profiles in the 15 micron band including overlapping of CO2 absorption with water vapor were calculated by a method in which flux transmittance is computed by means of a linear expansion and the multiplication rule, and maximum errors of 0.3 C/day were found in comparison with the exact line-by-line method.

  20. The 3D plant canopy radiative transfer analysis in an Alaskan black spruce forest: the characteristics of fraction of absorbed photosynthetically active radiation in the heterogeneous landscape

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Suzuki, R.; Nagai, S.; Nakai, T.; Kim, Y.

    2012-12-01

    Over the last couple of decades, the three dimensional plant canopy radiative transfer models have been developed, improved and used for the retrievals of biophysical variables of vegetative surface. Fraction of absorbed photosynthetically active radiation (FAPAR) by plant canopy, a similar variable to heating rate in the atmosphere, is one of the important biophysical variables to infer the terrestrial plant canopy photosynthesis. FAPAR can be estimated by the radiative transfer model inversion or the empirical relationships between FAPAR and vegetation indices such as normalized difference vegetation index (NDVI). To date, some global FAPAR products are publicly available. These products are estimated from the moderate resolution satellites such as MODIS and SPOT-VEGETATION. One may apply the similar FAPAR algorithms to higher spatial resolution satellites if the ecosystem structures are horizontally homogeneous, which means that the adjacent satellite pixels have a similar spectral properties. If the vegetation surface is highly heterogeneous, "domain average FAPAR", which assumes no net horizontal radiation fluxes, can be unrealistically high (more than 1). In this presentation, we analyzed the characteristics of FAPAR in a heterogeneous landscape. As a case study, we selected our study site in a sparse black spruce forest in Alaska. We conducted the field campaigns to measure forest structural and optical properties that are used in the radiative transfer simulation. We used a 3D radiative transfer, FLiES (Kobayashi, H. and H. Iwabuchi (2008), A coupled 1-D atmosphere and 3-D canopy radiative transfer model for canopy reflectance, light environment, and photosynthesis simulation in a heterogeneous landscape, Remote Sensing of Environment, 112, 173-185) to create a high resolution simulated spectral reflectance and FAPAR images over the course of the growing season. From the analysis, we show (1) FAPAR with no net horizontal fluxes assumption can be higher than

  1. Infrared characteristic radiation of water condensation and freezing in connection with atmospheric phenomena

    NASA Astrophysics Data System (ADS)

    Tatartchenko, Vitali A.

    2010-07-01

    This paper considers the emission of infrared characteristic radiation during the first order phase transitions of water (condensation and crystallization). Experimental results are analyzed in terms of their correspondence to the theoretical models. These models are based on the assumption that the particle's (atom, molecule, or cluster) transition from the higher energetic level (vapor or liquid) to a lower one (liquid or crystal) produces an emission of one or more photons. The energy of these photons depends on the latent energy of the phase transition and the character of bonds formed by the particle in the new phase. Based on experimental data, the author proposes a model explaining the appearance of a window of transparency for the characteristic radiation in the substances when first order phase transitions take place. The effect under investigation must play a very important role in atmospheric phenomena: it is one of the sources of Earth's cooling; formation of hailstorm clouds in the atmosphere is accompanied by intensive characteristic infrared radiation that could be detected for process characterization and meteorological warnings. The effect can be used for atmospheric heat accumulation. Together with the energy of wind, falling water, and solar energy, fog and cloud formation could give us a forth source of ecologically pure energy. Searching for the presence of water in the atmospheres of other planets might also be possible using this technique. Furthermore, this radiation might explain the red color and infrared emission of Jupiter.

  2. Mid- to Far-Infrared Spectral Energy Distribution of the Diffuse Galactic Radiation

    NASA Astrophysics Data System (ADS)

    Onaka, Takashi; Tokura, Daisuke; Sakon, Itsuki; Tajiri, Yuka Y.; Takagi, Toshinobu; Shibai, Hiroshi

    2007-01-01

    Mid-infrared (MIR; 12-60 μm) diffuse emission in the Galactic plane and the Carina Nebula is investigated relative to the far-infrared (FIR; >=100 μm) emission. Observations show that the ratio of the 12 μm emission to the total FIR intensity is more or less constant in the Galactic plane but exhibits a slight decrease followed by an increase as the FIR color becomes bluer in the Carina Nebula. The constancy is compatible with predictions from models of stochastic heating of very small grains or infrared fluorescence of polycyclic aromatic hydrocarbons. The decrease can be attributed to a weakening of the unidentified infrared band emission in strong radiation fields. Contrarily, the ratio of the 25 and 60 μm emission to FIR intensity increases linearly with field strength, which is incompatible with the model predictions. The Carina Nebula data show a much bluer FIR color than the Galactic plane, whereas the ratio of MIR to FIR emission is in a range similar to that of the plane. We interpret these characteristics in terms of a superposition of emission from dust grains in various radiation field strengths. The linear increase can be accounted for by an increasing contribution from emission by dust grains in strong radiation environments, whereas the shift in FIR color between the Galactic plane and the Carina Nebula can be attributed to different contributions from grains in weak radiation fields. Other possibilities, such as the effect of multiphoton processes, variations in the incident radiation spectrum, and possible contributions from iron grains, have also been examined, but none can account for the observations consistently. Applications of the present model to external galaxies are also discussed.

  3. Near infrared radiation damage mechanism in the lens

    NASA Astrophysics Data System (ADS)

    Söderberg, Per G.; Talebizadeh, Nooshin; Galichanin, Konstantin; Kronschläger, Martin; Schulmeister, Karl; Yu, Zhaohua

    2015-03-01

    The current data strongly indicates that there is no photochemical effect of in vivo exposure to 1090 nm near IRR radiation within the pupil. Four groups of 20 Sprague-Dawley rats were unilaterally exposed in vivo to 96 W·cm-2 centered inside the pupil for 10, 18, 33 and 60 min, respectively depending on group belonging. This resulted in radiant exposure doses of 57, 103, 198 and 344 kJ·cm-2. Temperature evolution at the limbus during the exposure and difference of intensity of forward light scattering between the exposed and the contralateral not exposed eye was measured at 1 week after exposure. The temperature at the limbus was found to increase exponentially towards an asymptote with an asymptote temperature of around 7 °C and a time constant (1/k) of around 15 s. No increase of light scattering was found despite that the cumulated radiant exposure dose was [80;250] times the threshold for photochemically induced cataract suggested by previous empirical data. It is concluded that at 1090 nm near IRR there is no photochemical effect.

  4. [Research on Spectrum Radiation Characteristics of a New Type Infrared/ Ultraviolet Dual Color Decoy].

    PubMed

    Chen, Chun-sheng; Dai, Meng-yan; Liu, Hai-feng; Xie, Chang-you; Zhang, Tong; Fang, Guo-feng

    2015-07-01

    The advantage of traditional MTV infrared decoys which are mainly consist of magnesium, Teflon and VITON is that it emits high radiant energy, so it is an effective countermeasure to traditional seekers which seek the target by heat source. The spectral radiant intensity which generated from high temperature combustion of MTV infrared decoys in near infrared region and ultraviolet band is very high, and that in Mid-IR region is relative lower, however the radiant intensity of real jet fighter in ultraviolet band is low and the infrared radiant intensity ratio of Mid-IR to near IR band is greater than 1. Thus, the traditional MTV infrared decoys are hardly able to counter the seekers equipped with dual color combined guidance system. Based on the spectral matching principle, we designed and prepared a new infrared/ultraviolet dual color decoy which is mainly consist of oxidant (wt% 45-75), fuel (wt% 10-25), energetic binder (wt% 25-50) and additives. We conducted theoretical calculations on combustion products of the reagent combinations using CEA (Chemic equilibrium & Application) software and initially determined the content of each component of the decoy formulation on the basis of the calculations results, then investigated the infrared radiation characteristics of decoys employing SR5000 spectrum radiometer and remote sensing interferometer spectrometer Tensor37 and analyzed the possible reasons for test results difference of the two systems separately from the test principle and calculation method, the testing environment, stability of testing results and other aspects. We studied the ultraviolet radiation characteristics of decoys using S2000 fiber optical spectrometer and the test results were consistent with the fighter ultraviolet radiant intensity which gained from theoretical calculation. We researched on the temperature characteristics of decoys by Imager IR 8325 mid-infrared thermal imager and it turned out that the dual color decoy is similar to the

  5. [Research on Spectrum Radiation Characteristics of a New Type Infrared/ Ultraviolet Dual Color Decoy].

    PubMed

    Chen, Chun-sheng; Dai, Meng-yan; Liu, Hai-feng; Xie, Chang-you; Zhang, Tong; Fang, Guo-feng

    2015-07-01

    The advantage of traditional MTV infrared decoys which are mainly consist of magnesium, Teflon and VITON is that it emits high radiant energy, so it is an effective countermeasure to traditional seekers which seek the target by heat source. The spectral radiant intensity which generated from high temperature combustion of MTV infrared decoys in near infrared region and ultraviolet band is very high, and that in Mid-IR region is relative lower, however the radiant intensity of real jet fighter in ultraviolet band is low and the infrared radiant intensity ratio of Mid-IR to near IR band is greater than 1. Thus, the traditional MTV infrared decoys are hardly able to counter the seekers equipped with dual color combined guidance system. Based on the spectral matching principle, we designed and prepared a new infrared/ultraviolet dual color decoy which is mainly consist of oxidant (wt% 45-75), fuel (wt% 10-25), energetic binder (wt% 25-50) and additives. We conducted theoretical calculations on combustion products of the reagent combinations using CEA (Chemic equilibrium & Application) software and initially determined the content of each component of the decoy formulation on the basis of the calculations results, then investigated the infrared radiation characteristics of decoys employing SR5000 spectrum radiometer and remote sensing interferometer spectrometer Tensor37 and analyzed the possible reasons for test results difference of the two systems separately from the test principle and calculation method, the testing environment, stability of testing results and other aspects. We studied the ultraviolet radiation characteristics of decoys using S2000 fiber optical spectrometer and the test results were consistent with the fighter ultraviolet radiant intensity which gained from theoretical calculation. We researched on the temperature characteristics of decoys by Imager IR 8325 mid-infrared thermal imager and it turned out that the dual color decoy is similar to the

  6. A far-infrared radiative closure study in the Arctic: Application to water vapor

    NASA Astrophysics Data System (ADS)

    Delamere, J. S.; Clough, S. A.; Payne, V. H.; Mlawer, E. J.; Turner, D. D.; Gamache, R. R.

    2010-09-01

    Far-infrared (λ > 15.0 μm) (far-IR) radiative processes provide a large fraction of Earth's outgoing longwave radiation and influence upper tropospheric vertical motion. Water vapor, because of its abundance and strong absorption properties over an extended spectral range, is the primary source of these radiative processes. Historically, the lack of spectrally resolved radiometric instruments and the opacity of the lower atmosphere have precluded extensive studies of far-IR water vapor absorption properties. The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program has organized a series of field experiments, the Radiative Heating in Underexplored Bands Campaigns (RHUBC), to address this deficiency. The first phase of RHUBC took place in 2007 at the ARM North Slope of Alaska Climate Research Facility. Measurements taken before and during this campaign have provided the basis for a clear-sky radiative closure study aimed at reducing key uncertainties associated with far-IR radiative transfer models. Extended-range Atmospheric Emitted Radiance Interferometer infrared radiance observations taken in clear sky conditions were compared against calculations from the Line-By-Line Radiative Transfer Model. The water vapor column amounts used in these calculations were retrieved from 183 GHz radiometer measurements. The uncertainty in these integrated water vapor retrievals is approximately 2%, a notable improvement over past studies. This far-IR radiative closure study resulted in an improvement to the Mlawer-Tobin Clough-Kneiyzs-Davies (MT_CKD) water vapor foreign continuum model and updates to numerous, far-IR water vapor line parameters from their values in the circa 2006 version of the HITRAN molecular line parameter database.

  7. Aerosol radiative effects in the ultraviolet, visible, and near-infrared spectral ranges using long-term aerosol data series over the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Mateos, D.; Antón, M.; Toledano, C.; Cachorro, V. E.; Alados-Arboledas, L.; Sorribas, M.; Costa, M. J.; Baldasano, J. M.

    2014-12-01

    A better understanding of aerosol radiative properties is a crucial challenge for climate change studies. This study aims at providing a complete characterization of aerosol radiative effects in different spectral ranges within the shortwave (SW) solar spectrum. For this purpose, long-term data sets of aerosol properties from six AERONET stations located in the Iberian Peninsula (southwestern Europe) have been analyzed in terms of climatological characterization and inter-annual changes. Aerosol information was used as input for the libRadtran model in order to determine the aerosol radiative effect (ARE) at the surface in the ultraviolet (AREUV), visible (AREVIS), near-infrared (ARENIR), and the entire SW range (ARESW) under cloud-free conditions. Over the whole Iberian Peninsula, yearly aerosol radiative effects in the different spectral ranges were found to be -1.1 < AREUV < -0.7, -5.7 < AREVIS < -3.5, -2.6 < ARENIR < -1.6, and -8.8 < ARESW < -5.7 (in W m-2). Monthly means of ARE showed a seasonal pattern with larger values in spring and summer. The aerosol forcing efficiency (AFE), ARE per unit of aerosol optical depth, has also been evaluated in the four spectral ranges. AFE exhibited a dependence on single scattering albedo as well as a weaker one on the Ångström exponent. AFE is larger (in absolute value) for small and absorbing particles. The contributions of the UV, VIS, and NIR ranges to the SW efficiency varied with the aerosol types. The predominant aerosol size determined the fractions AFEVIS/AFESW and AFENIR/AFESW. The AFEVIS was the dominant contributor for all aerosol types, although non-absorbing large particles caused more even contribution of VIS and NIR intervals. The AFEUV / AFESW ratio showed a higher value in the case of absorbing fine particles.

  8. Efficient and robust method for simultaneous reconstruction of the temperature distribution and radiative properties in absorbing, emitting, and scattering media

    NASA Astrophysics Data System (ADS)

    Niu, Chun-Yang; Qi, Hong; Huang, Xing; Ruan, Li-Ming; Tan, He-Ping

    2016-11-01

    A rapid computational method called generalized sourced multi-flux method (GSMFM) was developed to simulate outgoing radiative intensities in arbitrary directions at the boundary surfaces of absorbing, emitting, and scattering media which were served as input for the inverse analysis. A hybrid least-square QR decomposition-stochastic particle swarm optimization (LSQR-SPSO) algorithm based on the forward GSMFM solution was developed to simultaneously reconstruct multi-dimensional temperature distribution and absorption and scattering coefficients of the cylindrical participating media. The retrieval results for axisymmetric temperature distribution and non-axisymmetric temperature distribution indicated that the temperature distribution and scattering and absorption coefficients could be retrieved accurately using the LSQR-SPSO algorithm even with noisy data. Moreover, the influences of extinction coefficient and scattering albedo on the accuracy of the estimation were investigated, and the results suggested that the reconstruction accuracy decreased with the increase of extinction coefficient and the scattering albedo. Finally, a non-contact measurement platform of flame temperature field based on the light field imaging was set up to validate the reconstruction model experimentally.

  9. A radiochromic folm dosimeter for gamma radiation in the absorbed-dose range 0.1-10 kGy

    NASA Astrophysics Data System (ADS)

    Khan, Hasan M.; Farahani, Mahnaz; William L., McLaughlin

    A commercially available leuco-dye film (FWT-63-02), having a thickness of 0.55 mm, has been investigated spectrophotometrically for its characteristics as a radiochromic dosimeter and for its potential use in food-irradiation applications. The γ-ray irradiation of the nearly colorless, transparent film induces blue color with an absorption maximum at 600 nm. The increase in absorbance at 600 nm per unit thickness of film (Δ A mm -1) is linear with dose in the dose range up to 8 kGy, with a slope of 0.91 mm -1·kGy -1. After a modest additional increase during the first day following irradiation, the radiation-induced color is stable when stored at room temperature at least for 5 weeks. The response slope is 16% higher when stored at 60°C, however, after the initial 1-day increase it is stable for several weeks when stored at that temperature. The response of the dosimeter is independent of dose rate in the range 0.5-170 Gy min -1.

  10. Plasmon-enhanced energy transfer for improved upconversion of infrared radiation in doped-lanthanide nanocrystals.

    PubMed

    Sun, Qi-C; Mundoor, Haridas; Ribot, Josep C; Singh, Vivek; Smalyukh, Ivan I; Nagpal, Prashant

    2014-01-01

    Upconversion of infrared radiation into visible light has been investigated for applications in photovoltaics and biological imaging. However, low conversion efficiency due to small absorption cross-section for infrared light (Yb(3+)), and slow rate of energy transfer (to Er(3+) states) has prevented application of upconversion photoluminescence (UPL) for diffuse sunlight or imaging tissue samples. Here, we utilize resonant surface plasmon polaritons (SPP) waves to enhance UPL in doped-lanthanide nanocrystals. Our analysis indicates that SPP waves not only enhance the electromagnetic field, and hence weak Purcell effect, but also increase the rate of resonant energy transfer from Yb(3+) to Er(3+) ions by 6 fold. While we do observe strong metal mediated quenching (14-fold) of green fluorescence on flat metal surfaces, the nanostructured metal is resonant in the infrared and hence enhances the nanocrystal UPL. This strong Coulombic effect on energy transfer can have important implications for other fluorescent and excitonic systems too.

  11. Antenna-coupled thin-film far-infrared radiation detectors

    NASA Astrophysics Data System (ADS)

    Yasuoka, Yoshizumi; Kobayashi, Hiroaki; Shimizu, Takashi

    1996-06-01

    The 4 slot array antenna for 700 GHz far-infrared radiation are fabricated on the fused quartz substrates, making use of the dimensions obtained from the model experiments in the microwave region, and the power gain and directivity are obtained experimentally. The properties of fabricated array antenna agree with the theory, and 4 slot array antenna on the substrate of which thickness is odd multiples of a quarter dielectric wavelength improve the power gain by 5 dB compared with the single slot antenna on both sides of air and dielectric. These experimental data indicate that the fabricated antennas show the antenna pattern expected from the theory and work as array antennas for 700 GHz far- infrared laser radiation.

  12. Ultraviolet radiation effects on the infrared damage rate of a thermal control coating

    NASA Technical Reports Server (NTRS)

    Bass, J. A.

    1972-01-01

    The effects of ultraviolet radiation on the infrared reflectance of ZnO silicone white thermal coatings were investigated. Narrow band ultraviolet radiation for wavelengths in the 2200A to 3500A range by a monochromator and a high pressure, 150-W Eimac xenon lamp. The sample was irradiated while in a vacuum of at least 0.000001 torr, and infrared reflectance was measured in situ with a spectroreflectometer at 19,500A. Reflectance degradation was studied as a function of wavelength, time, intensity, and dose. Damage was wavelength dependent at constant exposure, but no maximum was evident above the shortest wavelength investigated here. The degradation rate at constant intensity was an exponential function of time and varies with intensity.

  13. Estimates of the generation of available potential energy by infrared radiation

    NASA Technical Reports Server (NTRS)

    Hansen, A. R.; Nagle, R. L.

    1984-01-01

    Data from the National Meteorological Center and net outgoing infrared radiation (IR) data measured by NOAA satellites for January 1977 are used to compute estimates of the spectral and spatial contributions to the net generation of available potential energy in the Northern Hemisphere due to infrared radiation. Although these estimates are necessarily crude, the results obtained indicate that IR causes destruction of both zonal and eddy available potential energy. The contributions from midlatitudes to the zonal and eddy generation are about -5.0 W/sq m and about -0.6 W/sq m, respectively. The eddy generation is due almost entirely to stationary wavenumbers one and two. Comparison with earlier studies and computation of Newtonian cooling coefficients are discussed.

  14. Case control study to assess the possibility of decrease the risk of osteoradionecrosis in relation to the dose of radiation absorbed by the jaw

    PubMed Central

    Carini, Fabrizio; Bucalo, Concetta; Saggese, Vito; Monai, Dario; Porcaro, Gianluca

    2012-01-01

    Summary Aims the assessment of the limit dose for the organs at risk in external radiotherapy is a fundamental step to guarantee an optimal risk-benefit ratio. The aim of this study was to assess, through contouring the single dental cavities, the absorbed radiation dose on irradiated alveolar bones during the treatment of cervico-facial tumours, so as to test the correlation between the absorbed dose of radiation at alveolar level and the level of individual surgical risk for osteonecrosis. Materials and methods we selected 45 out of 89 patients on the basis of different exclusion criteria. Nine of these patients showed evidence of osteoradionecrosis. The patients were treated either with 3D conformational radiation therapy (3D-CRT) or with intensity-modulated radiation therapy (IMRT), there after alveolar bones were contoured using computed axial tomography (CAT scans) carried out following oncological and dental treatment. The dose-volume histograms (DVH) were obtained on the basis of such data, which included those relating to the dental cavities in addition to those inherent to the tumours and the organs at risk. Results all patients, irrespective of type of treatment, received an average of 60 to 70 grays in 30/35 sittings. The patients treated with IMRT showed higher variation in absorbed radiation dose than those treated with 3D-CRT. The alveolar encirclement allowed the assessment of the absorbed radiation dose, and consequently it also allowed to assess the individual surgical risk for osteonecrosis in patients with head and neck tumours who underwent radiography treatment. Conclusions the study of DVH allows the assessment of limit dose and the detection of the areas at greater risk for osteoradionecrosis before dental surgery. PMID:23285316

  15. Dynamic response of UV-absorbing compounds, quantum yield and the xanthophyll cycle to diel changes in UV-B and photosynthetic radiations in an aquatic liverwort.

    PubMed

    Fabón, Gabriel; Monforte, Laura; Tomás-Las-Heras, Rafael; Núñez-Olivera, Encarnación; Martínez-Abaigar, Javier

    2012-01-01

    We studied the diel responses of the liverwort Jungermannia exsertifolia subsp. cordifolia to radiation changes under laboratory conditions. The samples were exposed to three radiation regimes: P (only PAR), PA (PAR+UV-A), and PAB (PAR+UV-A+UV-B). The day was divided in four periods: darkness, a first low-PAR period, the high-PAR plus UV period, and a second low-PAR period. After 15 days of culture, we measured photosynthetic pigments, chlorophyll fluorescence and UV-absorbing compounds in the four periods of the day on two consecutive days. With respect to UV-absorbing compounds, we analyzed their global amount (as the bulk UV absorbance of methanolic extracts) and the concentration of seven hydroxycinnamic acid derivatives, both in the soluble (mainly vacuolar) and insoluble (cell wall-bound) fractions of the plant extracts. PAB samples increased the bulk UV absorbance of the soluble and insoluble fractions, and the concentrations of p-coumaroylmalic acid in the soluble fraction and p-coumaric acid in the cell wall. Most of these variables showed significant diel changes and responded within a few hours to radiation changes (more strongly to UV-B), increasing at the end of the period of high-PAR plus UV. F(v)/F(m), Φ(PSII), NPQ and the components of the xanthophyll cycle showed significant and quick diel changes in response to high PAR, UV-A and UV-B radiation, indicating dynamic photoinhibition and protection of PSII from excess radiation through the xanthophyll cycle. Thus, the liverwort showed a dynamic protection and acclimation capacity to the irradiance level and spectral characteristics of the radiation received.

  16. The application of color display techniques for the analysis of Nimbus infrared radiation data

    NASA Technical Reports Server (NTRS)

    Allison, L. J.; Cherrix, G. T.; Ausfresser, H.

    1972-01-01

    A color enhancement system designed for the Applications Technology Satellite (ATS) spin scan experiment has been adapted for the analysis of Nimbus infrared radiation measurements. For a given scene recorded on magnetic tape by the Nimbus scanning radiometers, a virtually unlimited number of color images can be produced at the ATS Operations Control Center from a color selector paper tape input. Linear image interpolation has produced radiation analyses in which each brightness-color interval has a smooth boundary without any mosaic effects. An annotated latitude-longitude gridding program makes it possible to precisely locate geophysical parameters, which permits accurate interpretation of pertinent meteorological, geological, hydrological, and oceanographic features.

  17. Solar panel thermal cycling testing by solar simulation and infrared radiation methods

    NASA Technical Reports Server (NTRS)

    Nuss, H. E.

    1980-01-01

    For the solar panels of the European Space Agency (ESA) satellites OTS/MAROTS and ECS/MARECS the thermal cycling tests were performed by using solar simulation methods. The performance data of two different solar simulators used and the thermal test results are described. The solar simulation thermal cycling tests for the ECS/MARECS solar panels were carried out with the aid of a rotatable multipanel test rig by which simultaneous testing of three solar panels was possible. As an alternative thermal test method, the capability of an infrared radiation method was studied and infrared simulation tests for the ultralight panel and the INTELSAT 5 solar panels were performed. The setup and the characteristics of the infrared radiation unit using a quartz lamp array of approx. 15 sq and LN2-cooled shutter and the thermal test results are presented. The irradiation uniformity, the solar panel temperature distribution, temperature changing rates for both test methods are compared. Results indicate the infrared simulation is an effective solar panel thermal testing method.

  18. The effect of near-infrared MLS laser radiation on cell membrane structure and radical generation.

    PubMed

    Kujawa, Jolanta; Pasternak, Kamila; Zavodnik, Ilya; Irzmański, Robert; Wróbel, Dominika; Bryszewska, Maria

    2014-09-01

    The therapeutic effects of low-power laser radiation of different wavelengths and light doses are well known, but the biochemical mechanism of the interaction of laser light with living cells is not fully understood. We have investigated the effect of MLS (Multiwave Locked System) laser near-infrared irradiation on cell membrane structure, functional properties, and free radical generation using human red blood cells and breast cancer MCF-4 cells. The cells were irradiated with low-intensity MLS near-infrared (simultaneously 808 nm, continuous emission and 905 nm, pulse emission, pulse-wave frequency, 1,000 or 2,000 Hz) laser light at light doses from 0 to 15 J (average power density 212.5 mW/cm(2), spot size was 3.18 cm(2)) at 22 °C, the activity membrane bound acetylcholinesterase, cell stability, anti-oxidative activity, and free radical generation were the parameters used in characterizing the structural and functional changes of the cell. Near-infrared low-intensity laser radiation changed the acetylcholinesterase activity of the red blood cell membrane in a dose-dependent manner: There was a considerable increase of maximal enzymatic rate and Michaelis constant due to changes in the membrane structure. Integral parameters such as erythrocyte stability, membrane lipid peroxidation, or methemoglobin levels remained unchanged. Anti-oxidative capacity of the red blood cells increased after MLS laser irradiation. This irradiation induced a time-dependent increase in free radical generation in MCF-4 cells. Low-intensity near-infrared MLS laser radiation induces free radical generation and changes enzymatic and anti-oxidative activities of cellular components. Free radical generation may be the mechanism of the biomodulative effect of laser radiation.

  19. Pursuit of quantum monodromy in the far-infrared and mid-infrared spectra of NCNCS using synchrotron radiation.

    PubMed

    Winnewisser, Manfred; Winnewisser, Brenda P; De Lucia, Frank C; Tokaryk, Dennis W; Ross, Stephen C; Billinghurst, Brant E

    2014-09-01

    Quantum monodromy has a dramatic and defining impact on all those physical properties of chain-molecules that depend on a large-amplitude bending coordinate, including in particular the distribution of the ro-vibrational energy levels. As revealed by its pure rotational (a-type) spectrum [B. P. Winnewisser et al., Phys. Chem. Chem. Phys., 2010, 12, 8158-8189] cyanogen iso-thiocyanate, NCNCS, is a particularly illuminating exemplar of quantum monodromy: it clearly shows the distinctive monodromy-induced dislocation of the ro-vibrational energy level pattern for its low-lying bending mode. This dislocation centers on a lattice defect in the energy vs. momentum map of the ro-vibrational levels at the top of the barrier to linearity, and represents an example of an excited state quantum phase transition [D. Larese and F. Iachello, J. Mol. Struct., 2011, 1006, 611-628]. To complete the data, so far limited to ΔJ = +1 transitions, we decided to measure the high-resolution far-infrared band of the large-amplitude bending vibration ν7, and, if possible, mid-infrared bands. This Perspectives article presents our ongoing progress towards this goal, beginning with the description of how to predict line positions and intensities of the a- and b-type bands of the large amplitude bending mode using the Generalized-SemiRigid-Bender (GSRB) Hamiltonian for NCNCS and ab initio dipole moment functions [B. P. Winnewisser et al., Phys. Chem. Chem. Phys., 2010, 12, 8158-8189]. We include background information about synchrotron physics to clarify the advantages and limitations of that radiation source for our experiments. Details of the chemical preparation and sample handling, leading to the realization that NCNCS is 50 kJ mol(-1) lower in energy than its isomer S(CN)2 [Z. Kisiel et al., J. Phys. Chem. A, 2013, 117, 13815-13824] are included. We present the far-infrared and mid-infrared spectrum of NCNCS obtained at the Canadian Light Source synchrotron, using the IFS 125HR Bruker

  20. [Effects of Light Near-Infrared Radiation on Rats Assessed by Succinate Dehydrogenase Activity in Lymphocytes on Blood Smears].

    PubMed

    Khunderyakova, N V; Zakharchenko, A V; Zakharchenko, M V; Muller, H; Fedotcheva, I; Kondrashova, M N

    2015-01-01

    Biological effects of light near infrared radiation (850 nm), with modulation acoustic frequency of 101 Hz, was studied. The study was conducted on rats, the effect was recorded by succinate dehydrogenase activity in lymphocytes on the blood smear after administration of the activating dose of adrenaline, which simulates the state of the organism in the early stages of the pathogenic effects (stress). A pronounced regulating effect of infrared radiation on the activity of succinate dehydrogenase in animals activated by adrenaline was shown. Infrared radiation has a normalizing effect reducing the degree of inhibition or activation of the enzyme induced by adrenaline and had no effect on the control animals. Thus, by modulating the activity of succinate dehydrogenase infrared radiation regulates energy production in the mitochondria supported by the most powerful oxidation substrate--succinic acid, which is especially pronounced under stress. PMID:26841503

  1. [Effects of Light Near-Infrared Radiation on Rats Assessed by Succinate Dehydrogenase Activity in Lymphocytes on Blood Smears].

    PubMed

    Khunderyakova, N V; Zakharchenko, A V; Zakharchenko, M V; Muller, H; Fedotcheva, I; Kondrashova, M N

    2015-01-01

    Biological effects of light near infrared radiation (850 nm), with modulation acoustic frequency of 101 Hz, was studied. The study was conducted on rats, the effect was recorded by succinate dehydrogenase activity in lymphocytes on the blood smear after administration of the activating dose of adrenaline, which simulates the state of the organism in the early stages of the pathogenic effects (stress). A pronounced regulating effect of infrared radiation on the activity of succinate dehydrogenase in animals activated by adrenaline was shown. Infrared radiation has a normalizing effect reducing the degree of inhibition or activation of the enzyme induced by adrenaline and had no effect on the control animals. Thus, by modulating the activity of succinate dehydrogenase infrared radiation regulates energy production in the mitochondria supported by the most powerful oxidation substrate--succinic acid, which is especially pronounced under stress.

  2. Effect of infrared and X-ray radiation on thymus cells and the rate of growth of Ehrlich carcinoma.

    PubMed

    Dyukina, A R; Zaichkina, S I; Rozanova, O M; Aptikaeva, G F; Romanchenko, S P; Sorokina, S S

    2012-09-01

    We studied the effect of infrared light with a wavelength of 850 nm and modulated frequency of 101 Hz and X-ray radiation on the induction of cross-adaptive and radiation responses in the thymus and on the rate of tumor growth in mice in vivo. Preliminary exposure to infrared and X-ray radiation was shown to result in recovery in thymus weight after irradiation in a dose of 1.5 Gy and also inhibited the growth rate of Ehrlich carcinoma. These data attest to common mechanisms of the adaptive response induced by infrared and X-ray radiation in mice. Infrared light can be used as an adaptogen to adapt the animals to adverse factors.

  3. Properties of QSO Metal-line Absorption Systems at High Redshifts: Nature and Evolution of the Absorbers and New Evidence on Escape of Ionizing Radiation from Galaxies

    NASA Astrophysics Data System (ADS)

    Boksenberg, Alec; Sargent, Wallace L. W.

    2015-05-01

    Using Voigt-profile-fitting procedures on Keck High Resolution Spectrograph spectra of nine QSOs, we identify 1099 C IV absorber components clumped in 201 systems outside the Lyman forest over 1.6 <~ z <~ 4.4. With associated Si IV, C II, Si II and N V where available, we investigate the bulk statistical and ionization properties of the components and systems and find no significant change in redshift for C IV and Si IV while C II, Si II and N V change substantially. The C IV components exhibit strong clustering, but no clustering is detected for systems on scales from 150 km s-1 out to 50,000 km s-1. We conclude that the clustering is due entirely to the peculiar velocities of gas present in the circumgalactic media of galaxies. Using specific combinations of ionic ratios, we compare our observations with model ionization predictions for absorbers exposed to the metagalactic ionizing radiation background augmented by proximity radiation from their associated galaxies and find that the generally accepted means of radiative escape by transparent channels from the internal star-forming sites is spectrally not viable for our stronger absorbers. We develop an active scenario based on runaway stars with resulting changes in the efflux of radiation that naturally enable the needed spectral convergence, and in turn provide empirical indicators of morphological evolution in the associated galaxies. Together with a coexisting population of relatively compact galaxies indicated by the weaker absorbers in our sample, the collective escape of radiation is sufficient to maintain the intergalactic medium ionized over the full range 1.9 < z <~ 4.4. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck

  4. PROPERTIES OF QSO METAL-LINE ABSORPTION SYSTEMS AT HIGH REDSHIFTS: NATURE AND EVOLUTION OF THE ABSORBERS AND NEW EVIDENCE ON ESCAPE OF IONIZING RADIATION FROM GALAXIES

    SciTech Connect

    Boksenberg, Alec; Sargent, Wallace L. W.

    2015-05-15

    Using Voigt-profile-fitting procedures on Keck High Resolution Spectrograph spectra of nine QSOs, we identify 1099 C IV absorber components clumped in 201 systems outside the Lyman forest over 1.6 ≲ z ≲ 4.4. With associated Si IV, C II, Si II  and N V where available, we investigate the bulk statistical and ionization properties of the components and systems and find no significant change in redshift for C IV and Si IV while C II, Si II  and N V change substantially. The C IV components exhibit strong clustering, but no clustering is detected for systems on scales from 150 km s{sup –1} out to 50,000 km s{sup –1}. We conclude that the clustering is due entirely to the peculiar velocities of gas present in the circumgalactic media of galaxies. Using specific combinations of ionic ratios, we compare our observations with model ionization predictions for absorbers exposed to the metagalactic ionizing radiation background augmented by proximity radiation from their associated galaxies and find that the generally accepted means of radiative escape by transparent channels from the internal star-forming sites is spectrally not viable for our stronger absorbers. We develop an active scenario based on runaway stars with resulting changes in the efflux of radiation that naturally enable the needed spectral convergence, and in turn provide empirical indicators of morphological evolution in the associated galaxies. Together with a coexisting population of relatively compact galaxies indicated by the weaker absorbers in our sample, the collective escape of radiation is sufficient to maintain the intergalactic medium ionized over the full range 1.9 < z ≲ 4.4.

  5. Selective Pyroelectric Detection of Millimetre Waves Using Ultra-Thin Metasurface Absorbers

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Sergei A.; Paulish, Andrey G.; Navarro-Cía, Miguel; Arzhannikov, Andrey V.

    2016-02-01

    Sensing infrared radiation is done inexpensively with pyroelectric detectors that generate a temporary voltage when they are heated by the incident infrared radiation. Unfortunately the performance of these detectors deteriorates for longer wavelengths, leaving the detection of, for instance, millimetre-wave radiation to expensive approaches. We propose here a simple and effective method to enhance pyroelectric detection of the millimetre-wave radiation by combining a compact commercial infrared pyro-sensor with a metasurface-enabled ultra-thin absorber, which provides spectrally- and polarization-discriminated response and is 136 times thinner than the operating wavelength. It is demonstrated that, due to the small thickness and therefore the thermal capacity of the absorber, the detector keeps the high response speed and sensitivity to millimetre waves as the original infrared pyro-sensor does against the regime of infrared detection. An in-depth electromagnetic analysis of the ultra-thin resonant absorbers along with their complex characterization by a BWO-spectroscopy technique is presented. Built upon this initial study, integrated metasurface absorber pyroelectric sensors are implemented and tested experimentally, showing high sensitivity and very fast response to millimetre-wave radiation. The proposed approach paves the way for creating highly-efficient inexpensive compact sensors for spectro-polarimetric applications in the millimetre-wave and terahertz bands.

  6. Selective Pyroelectric Detection of Millimetre Waves Using Ultra-Thin Metasurface Absorbers

    PubMed Central

    Kuznetsov, Sergei A.; Paulish, Andrey G.; Navarro-Cía, Miguel; Arzhannikov, Andrey V.

    2016-01-01

    Sensing infrared radiation is done inexpensively with pyroelectric detectors that generate a temporary voltage when they are heated by the incident infrared radiation. Unfortunately the performance of these detectors deteriorates for longer wavelengths, leaving the detection of, for instance, millimetre-wave radiation to expensive approaches. We propose here a simple and effective method to enhance pyroelectric detection of the millimetre-wave radiation by combining a compact commercial infrared pyro-sensor with a metasurface-enabled ultra-thin absorber, which provides spectrally- and polarization-discriminated response and is 136 times thinner than the operating wavelength. It is demonstrated that, due to the small thickness and therefore the thermal capacity of the absorber, the detector keeps the high response speed and sensitivity to millimetre waves as the original infrared pyro-sensor does against the regime of infrared detection. An in-depth electromagnetic analysis of the ultra-thin resonant absorbers along with their complex characterization by a BWO-spectroscopy technique is presented. Built upon this initial study, integrated metasurface absorber pyroelectric sensors are implemented and tested experimentally, showing high sensitivity and very fast response to millimetre-wave radiation. The proposed approach paves the way for creating highly-efficient inexpensive compact sensors for spectro-polarimetric applications in the millimetre-wave and terahertz bands. PMID:26879250

  7. Selective Pyroelectric Detection of Millimetre Waves Using Ultra-Thin Metasurface Absorbers.

    PubMed

    Kuznetsov, Sergei A; Paulish, Andrey G; Navarro-Cía, Miguel; Arzhannikov, Andrey V

    2016-01-01

    Sensing infrared radiation is done inexpensively with pyroelectric detectors that generate a temporary voltage when they are heated by the incident infrared radiation. Unfortunately the performance of these detectors deteriorates for longer wavelengths, leaving the detection of, for instance, millimetre-wave radiation to expensive approaches. We propose here a simple and effective method to enhance pyroelectric detection of the millimetre-wave radiation by combining a compact commercial infrared pyro-sensor with a metasurface-enabled ultra-thin absorber, which provides spectrally- and polarization-discriminated response and is 136 times thinner than the operating wavelength. It is demonstrated that, due to the small thickness and therefore the thermal capacity of the absorber, the detector keeps the high response speed and sensitivity to millimetre waves as the original infrared pyro-sensor does against the regime of infrared detection. An in-depth electromagnetic analysis of the ultra-thin resonant absorbers along with their complex characterization by a BWO-spectroscopy technique is presented. Built upon this initial study, integrated metasurface absorber pyroelectric sensors are implemented and tested experimentally, showing high sensitivity and very fast response to millimetre-wave radiation. The proposed approach paves the way for creating highly-efficient inexpensive compact sensors for spectro-polarimetric applications in the millimetre-wave and terahertz bands. PMID:26879250

  8. Infrared radiative properties of alumina up to the melting point: A first-principles study

    NASA Astrophysics Data System (ADS)

    Yang, J. Y.; Xu, M.; Liu, L. H.

    2016-11-01

    The high thermal emission of alumina dominates the radiative heat transfer of rocket exhaust plume. Yet numerous experimental measurements on radiative properties of alumina at high temperatures vary considerably from each other and cannot provide physical insight into the underlying mechanism. In this work, the ab initio molecular dynamics (AIMD) method and ab initio parameterized Drude model are combined to predict the radiative properties of alumina for temperatures up to 2327 K (the melting point) in the spectral range 1-12 μm. Contributed by different microscopic processes, the optical absorption of alumina in the spectral range 1-4 and 4-12 μm is described by two distinct methods. In the spectral range 4-12 μm, the multi-phonon process mainly contributes to optical absorption and can be simulated by the AIMD method based on the linear response theory. While in the spectral range 1-4 μm, the optical absorption is mainly caused by intrinsic carriers and can be effectively described by the ab initio parameterized Drude model. The first-principles calculations can successfully predict the infrared radiative properties of alumina at high temperatures and well reproduce the literature experiments. Moreover, the theoretical simulations verify that alumina can retain its semiconducting character even in the liquid phase and there emerges sharp increase in the near-infrared optical absorption of alumina upon melting.

  9. Radiation temperature measurement method for semitransparent materials using one-channel infrared pyrometer.

    PubMed

    Fu, Tairan; Liu, Jiangfan; Zong, Anzhou

    2014-10-10

    Semitransparent zinc sulfide (ZnS) crystal materials are widely used as the infrared-transmitting windows for optical instruments operating in long wavelengths. This paper describes a temperature measurement method for high-temperature ZnS materials using the one-channel optical pyrometer based on a theoretical model of radiation transfer in semitransparent plates. Numerical analyses of the radiation properties of ZnS plate are used to optimize the spectral band for the optical pyrometry. The optimized measurement spectral band is based on a trade-off between the measurement radiation intensity and the signal-to-noise ratio (SNR) for the ZnS material. The effective waveband emittance of one-dimensional (1D) ZnS plates is analyzed for various experimental conditions (temperatures, thicknesses, and direction angles) for the one-channel infrared pyrometer with the optimized measurement spectral response. The analysis can be used to improve radiation temperature measurements of semitransparent ZnS materials in applications. PMID:25322390

  10. [Use of infrared radiations in the freeze-drying of foods (author's transl)].

    PubMed

    Maltini, E; Giangiacomo, R

    1976-01-01

    Use of near infrared radiation as heating source in freeze drying of food products, appear to be interesting both for the efficiency of the process and for its economical aspect. In the present paper the results obtained in freeze drying runs with heating plates and I.R. radiations are described. The obtained results show that: with increasing trays load of product, the I.R. system is more efficient than the traditional one; the product quality obtained is higher for I.R. radiation, especially with higher tray loads; the heat flux output of the I.R. system is much lower than the one of the heating plates, at the same level of subliming water.

  11. These images show thermal infrared radiation from Jupiter at different wavelengths which are diagnos

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images show thermal infrared radiation from Jupiter at different wavelengths which are diagnostic of physical phenomena The 7.85-micron image in the upper left shows stratospheric temperatures which are elevated in the region of the A fragment impact (to the left of bottom). Temperatures deeper in the atmosphere near 150-mbar are shown by the 17.2-micron image in the upper right. There is a small elevation of temperatures at this depth, indicated by the arrow, and confirmed by other measurements near this wavelength. This indicates that the influence of the impact of fragment A on the troposphere has been minimal. The two images in the bottom row show no readily apparent perturbation of the ammmonia condensate cloud field near 600 mbar, as diagnosed by 8.57-micron radiation, and deeper cloud layers which are diagnosed by 5-micron radiation.

  12. Shifting of infrared radiation using rotational raman resonances in diatomic molecular gases

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A device for shifting the frequency of infrared radiation from a CO.sub.2 laser by stimulated Raman scattering in either H.sub.2 or D.sub.2. The device of the preferred embodiment comprises an H.sub.2 Raman laser having dichroic mirrors which are reflective for 16 .mu.m radiation and transmittive for 10 .mu.m, disposed at opposite ends of an interaction cell. The interaction cell contains a diatomic molecular gas, e.g., H.sub.2, D.sub.2, T.sub.2, HD, HT, DT and a capillary waveguide disposed within the cell. A liquid nitrogen jacket is provided around the capillary waveguide for the purpose of cooling. In another embodiment the input CO.sub.2 radiation is circularly polarized using a Fresnel rhomb .lambda./4 plate and applied to an interaction cell of much longer length for single pass operation.

  13. Infrared radiation in the mesosphere and lower thermosphere: energetic effects and coupling with lower atmosphere

    NASA Astrophysics Data System (ADS)

    Feofilov, Artem; Kutepov, Alexander; Rezac, Ladislav

    2013-04-01

    The translational degrees of freedom of atmospheric molecular and atomic gaseous compounds represent the heat reservoir. This reservoir obtains or loses energy due to a number of sources and sinks, among them heating and cooling related to various types of mass motions, redistribution of energy released in the course of various photochemical reactions (the translational energy, the chemical energy and the nascent electronic, vibration and rotational energy of the reaction products), and absorption and emission of the infrared (IR) radiation. In the latter case, one deals with interaction between matter and the IR radiative field, which, for the case of the mesosphere/lower thermosphere (MLT), includes the atmospheric radiation formed in these layers, the upwelling radiation from the ground and lower atmosphere, and, during daytime, the IR solar radiation. In this talk, we address the energetic effects of IR radiation in the MLT and its radiative coupling with lower atmosphere by analyzing the interaction between IR radiation and matter. In the MLT, this interaction is strongly affected by the situation when vibrational (and in its upper part also rotational) excitation of the molecules does not obey Boltzmann's law with the local kinetic temperature. As a result, the IR radiation emitted in these layers does not reflect the thermal state of matter. This situation is referred to as the breakdown of local thermodynamic equilibrium (LTE) for the vibrational (or rotational-vibrational) degrees of freedom. Detailed treatment of non-LTE plays a crucial role for estimating thermal effects of the IR radiation as well as for the diagnostics of space-based IR observations. We discuss the peculiarities of the non-LTE radiation formation in the IR bands of CO2, O3, and H2O molecules, estimate radiative cooling/heating rates for typical atmospheric scenarios, and analyze sensitivity of the MLT radiative energy balance to various mechanisms of populating/depopulating molecular

  14. Technical report series on global modeling and data assimilation. Volume 3: An efficient thermal infrared radiation parameterization for use in general circulation models

    NASA Technical Reports Server (NTRS)

    Suarex, Max J. (Editor); Chou, Ming-Dah

    1994-01-01

    A detailed description of a parameterization for thermal infrared radiative transfer designed specifically for use in global climate models is presented. The parameterization includes the effects of the main absorbers of terrestrial radiation: water vapor, carbon dioxide, and ozone. While being computationally efficient, the schemes compute very accurately the clear-sky fluxes and cooling rates from the Earth's surface to 0.01 mb. This combination of accuracy and speed makes the parameterization suitable for both tropospheric and middle atmospheric modeling applications. Since no transmittances are precomputed the atmospheric layers and the vertical distribution of the absorbers may be freely specified. The scheme can also account for any vertical distribution of fractional cloudiness with arbitrary optical thickness. These features make the parameterization very flexible and extremely well suited for use in climate modeling studies. In addition, the numerics and the FORTRAN implementation have been carefully designed to conserve both memory and computer time. This code should be particularly attractive to those contemplating long-term climate simulations, wishing to model the middle atmosphere, or planning to use a large number of levels in the vertical.

  15. Effect of infrared and microwave radiations on properties of Indian Horse Chestnut starch.

    PubMed

    Shah, Umar; Gani, Adil; Ashwar, Bilal Ahmad; Shah, Asima; Wani, Idrees Ahmed; Masoodi, Farooq Ahmad

    2016-03-01

    Starch extracted from Indian Horse Chestnut (IHCN) was subjected to infrared and microwave radiations for different time intervals (15 s, 30 s, & 45 s) at constant dose. The structural change of MW and IR radiated IHCN starches were determined by Fourier transform-infra red spectroscopy. The increased peak intensity at 3240 cm(-1) of treated starch represents more exposure of hydroxyl groups due to radiation. Granule morphology of native starch showed round and elliptical granules with smooth surfaces. However radiation treatment resulted in the development of surface cracks. Effect of radiation on physicochemical properties of starch revealed increase in water absorption capacity and light transmittance and decrease in apparent amylose content, pH, and syneresis. The peak, trough, final, and setback viscosities were significantly reduced with increase in treatment time. Radiated starches displayed significantly lower values of To,Tp, and ΔHgel than native starch. Further antioxidant activities were evaluated by DPPH and FRAP assays. Results showed significant improvement in antioxidant activity of starch by both MW and IR treatments.

  16. Contrail microphysical properties and radiative forcing over the Northern Hemisphere derived using MODIS infrared observations

    NASA Astrophysics Data System (ADS)

    Bedka, S. T.; Minnis, P.; Duda, D. P.; Spangenberg, D.; Chee, T.; Khlopenkov, K. V.

    2015-12-01

    One of the primary ways that air traffic affects the Earth's radiation budget is through the formation of contrails. In order to quantify the radiative impact of contrails, one must assess their macro and microphysical properties (e.g. contrail temperature, optical depth and effective particle size) as well as the characteristics of the environment in which they occur (e.g. background radiation field and cloud properties). In-situ measurements of contrail microphysical properties are limited, and hence the retrieval of such properties from remotely sensed satellite data is useful. This paper details the ongoing progress being made to retrieve contrail properties and calculate the contrail radiative forcing from 2 years of MODIS (Moderate Resolution Imaging Spectroradiometer) Aqua and Terra data. Contrail microphysical properties from the seasonal months (January, April, July, October) of 2006 and 2012 are derived using an infrared-only heritage algorithm developed at NASA Langley for the Clouds and the Earth's Radiant Energy System (CERES) program. Results are subset by day/night, although the same retrieval algorithm will be used for all granules. Contrail properties and background cloud properties are then used as input into the Fu-Liou radiative transfer model to compute the overall contrail radiative forcing.

  17. Quantitative proteomics reveals middle infrared radiation-interfered networks in breast cancer cells.

    PubMed

    Chang, Hsin-Yi; Li, Ming-Hua; Huang, Tsui-Chin; Hsu, Chia-Lang; Tsai, Shang-Ru; Lee, Si-Chen; Huang, Hsuan-Cheng; Juan, Hsueh-Fen

    2015-02-01

    Breast cancer is one of the leading cancer-related causes of death worldwide. Treatment of triple-negative breast cancer (TNBC) is complex and challenging, especially when metastasis has developed. In this study, we applied infrared radiation as an alternative approach for the treatment of TNBC. We used middle infrared (MIR) with a wavelength range of 3-5 μm to irradiate breast cancer cells. MIR significantly inhibited cell proliferation in several breast cancer cells but did not affect the growth of normal breast epithelial cells. We performed iTRAQ-coupled LC-MS/MS analysis to investigate the MIR-triggered molecular mechanisms in breast cancer cells. A total of 1749 proteins were identified, quantified, and subjected to functional enrichment analysis. From the constructed functionally enriched network, we confirmed that MIR caused G2/M cell cycle arrest, remodeled the microtubule network to an astral pole arrangement, altered the actin filament formation and focal adhesion molecule localization, and reduced cell migration activity and invasion ability. Our results reveal the coordinative effects of MIR-regulated physiological responses in concentrated networks, demonstrating the potential implementation of infrared radiation in breast cancer therapy.

  18. Quantitative proteomics reveals middle infrared radiation-interfered networks in breast cancer cells.

    PubMed

    Chang, Hsin-Yi; Li, Ming-Hua; Huang, Tsui-Chin; Hsu, Chia-Lang; Tsai, Shang-Ru; Lee, Si-Chen; Huang, Hsuan-Cheng; Juan, Hsueh-Fen

    2015-02-01

    Breast cancer is one of the leading cancer-related causes of death worldwide. Treatment of triple-negative breast cancer (TNBC) is complex and challenging, especially when metastasis has developed. In this study, we applied infrared radiation as an alternative approach for the treatment of TNBC. We used middle infrared (MIR) with a wavelength range of 3-5 μm to irradiate breast cancer cells. MIR significantly inhibited cell proliferation in several breast cancer cells but did not affect the growth of normal breast epithelial cells. We performed iTRAQ-coupled LC-MS/MS analysis to investigate the MIR-triggered molecular mechanisms in breast cancer cells. A total of 1749 proteins were identified, quantified, and subjected to functional enrichment analysis. From the constructed functionally enriched network, we confirmed that MIR caused G2/M cell cycle arrest, remodeled the microtubule network to an astral pole arrangement, altered the actin filament formation and focal adhesion molecule localization, and reduced cell migration activity and invasion ability. Our results reveal the coordinative effects of MIR-regulated physiological responses in concentrated networks, demonstrating the potential implementation of infrared radiation in breast cancer therapy. PMID:25556991

  19. Near-infrared radiation absorption properties of covellite (CuS) using first-principles calculations

    NASA Astrophysics Data System (ADS)

    Xiao, Lihua; Wu, Jianming; Ran, Jingyu; Liu, Yike; Qiu, Wei; Lu, Fanghai; Shao, Fang; Tang, Dongsheng; Peng, Ping

    2016-08-01

    First-principles density functional theory was used to investigate the electronic structure, optical properties and the origin of the near-infrared (NIR) absorption of covellite (CuS). The calculated lattice constant and optical properties are found to be in reasonable agreement with experimental and theoretical findings. The electronic structure reveals that the valence and conduction bands of covellite are determined by the Cu 3d and S 3p states. By analyzing its optical properties, we can fully understand the potential of covellite (CuS) as a NIR absorbing material. Our results show that covellite (CuS) exhibits NIR absorption due to its metal-like plasma oscillation in the NIR range.

  20. Applications of infrared synchrotron radiation to microanalysis of advanced composite systems

    SciTech Connect

    Meilunas, R.; Carr, G.L.; Tobin, A.

    1995-12-31

    The utility of characterizing both polymer and ceramic matrix composites, using the enhanced sensitivity provided by an infrared microscope integrated with a synchrotron light source, is investigated. It is shown that by substitution of the conventional infrared globar source in the microscope with high brightness IR synchrotron radiation, an increase in spectral sensitivity for both microtransmission and microreflectance can be obtained over significantly reduced sampling (aperture) areas. The improved microreflectance capability is found to considerably simplify the characterization of structural composites by eliminating the difficult microtome sectioning typically required for IR microanalysis over small (< 10 x 10 micron) sample areas. Application of the technique to thermo-oxidative stability studies of polyimide / carbon fiber composite and silicon carboxide glass (Blackglas) / Nextel fiber ceramic matrix composite systems is presented.

  1. Performance of the HIRS/2 instrument on TIROS-N. [High Resolution Infrared Radiation Sounder

    NASA Technical Reports Server (NTRS)

    Koenig, E. W.

    1980-01-01

    The High Resolution Infrared Radiation Sounder (HIRS/2) was developed and flown on the TIROS-N satellite as one means of obtaining atmospheric vertical profile information. The HIRS/2 receives visible and infrared spectrum radiation through a single telescope and selects 20 narrow radiation channels by means of a rotating filter wheel. A passive radiant cooler provides an operating temperature of 106.7 K for the HgCdTe and InSb detectors while the visible detector operates at instrument frame temperature. Low noise amplifiers and digital processing provide 13 bit data for spacecraft data multiplexing and transmission. The qualities of system performance that determine sounding capability are the dynamic range of data collection, the noise equivalent radiance of the system, the registration of the air columns sampled in each channel and the ability to upgrade the calibration of the instrument to maintain the performance standard throughout life. The basic features, operating characteristics and performance of the instrument in test are described. Early orbital information from the TIROS-N launched on October 13, 1978 is given and some observations on system quality are made.

  2. Susceptibility of Tribolium castaneum (Coleoptera: Tenebrionidae) life stages to flameless catalytic infrared radiation.

    PubMed

    Khamis, Moses; Subramanyam, Bhadriraju; Flinn, Paul W; Dogan, Hulya; Gwirtz, Jeffrey A

    2011-02-01

    The susceptibility of various life stages of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), a pest of stored wheat, Triticum aestivum L., to flameless catalytic infrared radiation in the 3-7-microm range was evaluated in the laboratory. Immature stages were collected from flour infested with T. castaneum adults only for 1 d. Stages collected after 1 d represented eggs (collected on day 0); those collected after 7, 14, and 21 d from day 0 represented larvae in different developmental stages, whereas those collected after 24 d represented pupae. Adults (2 wk old) were collected after 42 d. Each of these stages was exposed for 45 or 60 s in 113.5 or 227.0 g of wheat at a distance of 8.0 or 12.7 cm from a bench top infrared emitter. The mean temperatures attained during exposures were measured continuously using a noncontact infrared thermometer connected to a computer. The mean grain temperatures attained increased with an increase in exposure time and were inversely related to distance from the emitter. Grain quantity least influenced mean temperatures attained. Pupae were the least susceptible stage and larvae collected after 7 d were the most susceptible stage. Variation in probability of death of various life stages decreased with an increase in mean grain temperatures attained. All life stages were killed after a 60-s exposure at a distance of 8.0 cm from the emitter in 113.5 g of wheat, where the mean +/- SE temperatures attained ranged from 107.6 +/- 1.2 to 111.4 +/- 0.5 degrees C. Our laboratory results using small grain quantities and short exposure times showed that flameless catalytic infrared radiation can be a valuable tool for managing insects in stored organic and nonorganic wheat.

  3. 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

  4. A method for computing visible and infrared polarized monochromatic radiation in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Wauben, W. M. F.; de Haan, J. F.; Hovenier, J. W.

    1994-02-01

    In this paper we present a computational method, based on the so-called adding principle, for calculating the polarized monochromatic radiation in plane-parallel vertically inhomogeneous atmospheres. Our computer code is verified by comparing numerical results with those obtained by other investigators using different methods. We consider not only the well-known case of illumination by a unidirectional beam of light at the top of the atmosphere, but also illumination by isotropically radiating internal sources and illumination by an isotropically radiating ground surface below the atmosphere. Numerical results for all relevant Stokes parameters are tabulated for a two-layer atmosphere containing molecules and haze particles. These results pertain to the three types of illumination mentioned above. Furthermore, we describe some general features of polarized radiation in an optically thick homogeneous atmosphere containing cloud C1 water droplets. It is shown that multiple scattering of radiation in such a cloudy atmosphere may not be ignored at infrared wavelengths if molecular absorption is negligible.

  5. Using Fourier transform infrared (FT-IR) absorbance spectroscopy and multivariate analysis to study the effect of chlorine-induced bacterial injury in water.

    PubMed

    Al-Qadiri, Hamzah M; Al-Alami, Nivin I; Al-Holy, Murad A; Rasco, Barbara A

    2008-10-01

    The effect of chlorine-induced bacterial injury on spectral features using Fourier transform infrared (FT-IR) absorbance spectroscopy was studied using a mixed bacterial culture of (1:1) ca. 500 CFU/mL each Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 15442 in 0.9% saline. Bacterial cells were treated with 0, 0.3, or 1.0 ppm of initial free chlorine (21 degrees C, 1 h of contact time). Chlorine-injured and dead bacterial cells retained the ATR spectral properties of uninjured or live cells in the region of C-O-C stretching vibrations of polysaccharides, indicative of the cell wall peptidoglycan layer and lipopolysaccharide outer leaflet. This confirms the observations of others that extensive bacterial membrane damage is not a key factor in the inactivation of bacteria by chlorine. The bactericidal effect of chlorine caused changes in the spectral features of bacterial ester functional groups of lipids, structural proteins, and nucleic acids, with apparent denaturation reflected between 1800 and 1300 cm (-1) for injured bacterial cells. Three-dimensional principal component analysis (PCA) showed distinct segregation and clustering of chlorine-treated and untreated cells. Cells exposed to chlorine at 0.3 or 1.0 ppm could be distinguished from the untreated control 73 and 80% of the time, respectively, using soft independent modeling of class analogy (SIMCA) analysis. This study suggests that FT-IR spectroscopy may be applicable for detecting the presence of injured and viable but not culturable (VBNC) waterborne pathogens that are underestimated or not discernible using conventional microbial techniques.

  6. Soil moisture estimation using reflected solar and emitted thermal infrared radiation

    NASA Technical Reports Server (NTRS)

    Jackson, R. D.; Cihlar, J.; Estes, J. E.; Heilman, J. L.; Kahle, A.; Kanemasu, E. T.; Millard, J.; Price, J. C.; Wiegand, C. L.

    1978-01-01

    Classical methods of measuring soil moisture such as gravimetric sampling and the use of neutron moisture probes are useful for cases where a point measurement is sufficient to approximate the water content of a small surrounding area. However, there is an increasing need for rapid and repetitive estimations of soil moisture over large areas. Remote sensing techniques potentially have the capability of meeting this need. The use of reflected-solar and emitted thermal-infrared radiation, measured remotely, to estimate soil moisture is examined.

  7. Pulsed mid-infrared radiation from spectral broadening in laser wakefield simulations

    SciTech Connect

    Zhu, W.; Palastro, J. P.; Antonsen, T. M.

    2013-07-15

    Spectral red-shifting of high power laser pulses propagating through underdense plasma can be a source of ultrashort mid-infrared (MIR) radiation. During propagation, a high power laser pulse drives large amplitude plasma waves, depleting the pulse energy. At the same time, the large amplitude plasma wave provides a dynamic dielectric response that leads to spectral shifting. The loss of laser pulse energy and the approximate conservation of laser pulse action imply that spectral red-shifts accompany the depletion. In this paper, we investigate, through simulation, the parametric dependence of MIR generation on pulse energy, initial pulse duration, and plasma density.

  8. 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.

  9. Extinction of visible and infrared radiation in rain Comparison of theory and experiment

    NASA Technical Reports Server (NTRS)

    Ulbrich, C. W.; Atlas, D.

    1985-01-01

    A critical review is given of the experimental and theoretical results concerning the measurement of rainfall using optical extinction, i.e., the attenuation of radiation with wavelength less than or equal to that of the infrared band. It is shown that rainfall rates found from an empirical relation involving optical extinction generally display average deviations without regard for sign of only 25 percent when compared with those measured by raingages directly beneath the optical beam. It is also shown that the differences between experimental and theoretical results can be explained in terms of variations of the shape of the raindrop size distribution, i.e., deviations from exponentiality.

  10. Absorption of infrared radiation by electrons in the field of a neutral hydrogen atom

    NASA Technical Reports Server (NTRS)

    Stallcop, J. R.

    1974-01-01

    An analytical expression for the absorption coefficient is developed from a relationship between the cross-section for inverse bremsstrahlung absorption and the cross-section for electron-atom momentum transfer; it is accurate for those photon frequencies v and temperatures such that hv/kT is small. The determination of the absorption of infrared radiation by free-free transitions of the negative hydrogen ion has been extended to higher temperatures. A simple analytical expression for the absorption coefficient has been derived.

  11. Photoblepharokeratoconjunctivitis caused by invisible infrared radiation emitted from a green laser pointer.

    PubMed

    Khedr, Yahya A H; Khedr, Abdulla H

    2014-01-01

    There are a wide variety of laser pointers sold to the general public. Among those are the high-powered diode-pumped solid-state lasers (>5 mW), which do not follow the laser safety regulations for packing, and are sold as regular lasers without the infrared (IR) filters. In this case report, we encountered a patient with photoblepharokeratoconjunctivitis caused by the invisible IR radiations emitted from a green laser pointer. Owing to the thermal effect of the invisible IR rays led to the disease. PMID:24618868

  12. Extension of radiative transfer code MOMO, matrix-operator model to the thermal infrared - Clear air validation by comparison to RTTOV and application to CALIPSO-IIR

    NASA Astrophysics Data System (ADS)

    Doppler, Lionel; Carbajal-Henken, Cintia; Pelon, Jacques; Ravetta, François; Fischer, Jürgen

    2014-09-01

    1-D radiative transfer code Matrix-Operator Model (MOMO), has been extended from [0.2-3.65 μm] the band to the whole [0.2-100 μm] spectrum. MOMO can now be used for the computation of a full range of radiation budgets (shortwave and longwave). This extension to the longwave part of the electromagnetic radiation required to consider radiative transfer processes that are features of the thermal infrared: the spectroscopy of the water vapor self- and foreign-continuum of absorption at 12 μm and the emission of radiation by gases, aerosol, clouds and surface. MOMO's spectroscopy module, Coefficient of Gas Absorption (CGASA), has been developed for computation of gas extinction coefficients, considering continua and spectral line absorptions. The spectral dependences of gas emission/absorption coefficients and of Planck's function are treated using a k-distribution. The emission of radiation is implemented in the adding-doubling process of the matrix operator method using Schwarzschild's approach in the radiative transfer equation (a pure absorbing/emitting medium, namely without scattering). Within the layer, the Planck-function is assumed to have an exponential dependence on the optical-depth. In this paper, validation tests are presented for clear air case studies: comparisons to the analytical solution of a monochromatic Schwarzschild's case without scattering show an error of less than 0.07% for a realistic atmosphere with an optical depth and a blackbody temperature that decrease linearly with altitude. Comparisons to radiative transfer code RTTOV are presented for simulations of top of atmosphere brightness temperature for channels of the space-borne instrument MODIS. Results show an agreement varying from 0.1 K to less than 1 K depending on the channel. Finally MOMO results are compared to CALIPSO Infrared Imager Radiometer (IIR) measurements for clear air cases. A good agreement was found between computed and observed radiance: biases are smaller than 0.5 K

  13. Enhanced thermal radiation in terahertz and far-infrared regime by hot phonon excitation in a field effect transistor

    SciTech Connect

    Chung, Pei-Kang; Yen, Shun-Tung

    2014-11-14

    We demonstrate the hot phonon effect on thermal radiation in the terahertz and far-infrared regime. A pseudomorphic high electron mobility transistor is used for efficiently exciting hot phonons. Boosting the hot phonon population can enhance the efficiency of thermal radiation. The transistor can yield at least a radiation power of 13 μW and a power conversion efficiency higher than a resistor by more than 20%.

  14. Status of the solar and infrared radiation submodels in the LLNL 1-D and 2-D chemical-transport models

    SciTech Connect

    Grant, K.E.; Taylor, K.E.; Ellis, J.S.; Wuebbles, D.J.

    1987-07-01

    The authors have implemented a series of state of the art radiation transport submodels in previously developed one dimensional and two dimensional chemical transport models of the troposphere and stratosphere. These submodels provide the capability of calculating accurate solar and infrared heating rates. They are a firm basis for further radiation submodel development as well as for studying interactions between radiation and model dynamics under varying conditions of clear sky, clouds, and aerosols. 37 refs., 3 figs.

  15. The polarization of the far-infrared radiation from the Galactic center

    NASA Technical Reports Server (NTRS)

    Werner, M. W.; Davidson, J. A.; Morris, M.; Novak, G.; Platt, S. R.

    1988-01-01

    The first detection of linear polarization of the far-infrared (100-micron) radiation from the about 3-pc-diameter dust ring surrounding the galactic nucleus is reported. The percentage of polarization is between 1 and 2 percent at the three measured positions. It is argued that the polarized radiation is produced by thermal emission from elongated interstellar grains oriented by the local magnetic field. The dust ring is optically thin at 100 microns; therefore the observations sample dust through the entire depth of the cloud and are free of confusing effects due to embedded sources, scattering, or selective absorption. These data provide the first information about the configuration of the magnetic field in the dust ring.

  16. Dichroic filters to protect milliwatt far-infrared detectors from megawatt ECRH radiation.

    PubMed

    Bertschinger, G; Endres, C P; Lewen, F; Oosterbeek, J W

    2008-10-01

    Dichroic filters have been used to shield effectively the far infrared (FIR) detectors at the interferometer/polarimeter on TEXTOR. The filters consist of metal foils with regular holes, the hole diameter, the mutual spacing and the thickness of the foils are chosen to transmit radiation at the design frequency with transmission >90%. The attenuation at the low frequency end of the bandpass filter is about 30 dB per octave, the high frequency transmission is between 20% and 40%. The filters have been used to block the stray radiation from the megawatt microwave heating beam to the detectors of the FIR interferometer, operating with power on the detector in the milliwatt range. If required, the low frequency attenuation can be still enhanced, without compromising the transmission in the passband. The FIR interferometer used for plasma density and position control is no longer disturbed by electromagnetic waves used for plasma heating.

  17. Infrared radiation from hot cones on cool conifers attracts seed-feeding insects

    PubMed Central

    Takács, Stephen; Bottomley, Hannah; Andreller, Iisak; Zaradnik, Tracy; Schwarz, Joseph; Bennett, Robb; Strong, Ward; Gries, Gerhard

    2008-01-01

    Foraging animals use diverse cues to locate resources. Common foraging cues have visual, auditory, olfactory, tactile or gustatory characteristics. Here, we show a foraging herbivore using infrared (IR) radiation from living plants as a host-finding cue. We present data revealing that (i) conifer cones are warmer and emit more near-, mid- and long-range IR radiation than needles, (ii) cone-feeding western conifer seed bugs, Leptoglossus occidentalis (Hemiptera: Coreidae), possess IR receptive organs and orient towards experimental IR cues, and (iii) occlusion of the insects' IR receptors impairs IR perception. The conifers' cost of attracting cone-feeding insects may be offset by occasional mast seeding resulting in cone crops too large to be effectively exploited by herbivores. PMID:18945664

  18. Retinal safety of near infrared radiation in photovoltaic restoration of sight

    PubMed Central

    Lorach, H.; Wang, J.; Lee, D. Y.; Dalal, R.; Huie, P.; Palanker, D.

    2015-01-01

    Photovoltaic restoration of sight requires intense near-infrared light to effectively stimulate retinal neurons. We assess the retinal safety of such radiation with and without the retinal implant. Retinal damage threshold was determined in pigmented rabbits exposed to 880nm laser radiation. The 50% probability (ED50) of retinal damage during 100s exposures with 1.2mm diameter beam occurred at 175mW, corresponding to a modeled temperature rise of 12.5°C. With the implant, the same temperature was reached at 78mW, close to the experimental ED50 of 71mW. In typical use conditions, the retinal temperature rise is not expected to exceed 0.43°C, well within the safety limits for chronic use. PMID:26819813

  19. Infrared radiation from hot cones on cool conifers attracts seed-feeding insects.

    PubMed

    Takács, Stephen; Bottomley, Hannah; Andreller, Iisak; Zaradnik, Tracy; Schwarz, Joseph; Bennett, Robb; Strong, Ward; Gries, Gerhard

    2009-02-22

    Foraging animals use diverse cues to locate resources. Common foraging cues have visual, auditory, olfactory, tactile or gustatory characteristics. Here, we show a foraging herbivore using infrared (IR) radiation from living plants as a host-finding cue. We present data revealing that (i) conifer cones are warmer and emit more near-, mid- and long-range IR radiation than needles, (ii) cone-feeding western conifer seed bugs, Leptoglossus occidentalis (Hemiptera: Coreidae), possess IR receptive organs and orient towards experimental IR cues, and (iii) occlusion of the insects' IR receptors impairs IR perception. The conifers' cost of attracting cone-feeding insects may be offset by occasional mast seeding resulting in cone crops too large to be effectively exploited by herbivores.

  20. Infrared radiation suppresses ultraviolet B-induced sunburn-cell formation.

    PubMed

    Danno, K; Horio, T; Imamura, S

    1992-01-01

    Sunburn cell (SC) formation, a quantifiable measure of epidermal cell injury induced in mouse ear skin by ultraviolet-B (UVB) radiation (290-320 nm), was significantly decreased by pre-exposure to infrared radiation (IR), which elevated the surface temperature of ear lobes to 37-42 degrees C. An autoradiographic study demonstrated that the basal cell labelling indices were significantly reduced in a surface temperature-dependent manner by pre-exposure to IR. Taken together with our previous findings that SC formation depends upon the ratio of cycling to non-cycling cells, the present findings suggest that IR retards the cell cycle and, as a result, decreases SC formation. SC counts were not altered by post-UVB exposure to IR. The effect of IR or the IR-induced increase in surface temperature should be considered when studying cutaneous damage by UVB and sunlight.

  1. Effect of UV-B radiation on UV absorbing compounds and pigments of moss and lichen of Schirmacher oasis region, East Antarctica.

    PubMed

    Singh, J; Gautam, S; Bhushan Pant, A

    2012-01-01

    The survival of Antarctic flora under ozone depletion depends on their ability to acclimate against increasing UV—B radiation by employing photo protective mechanisms either by avoiding or repairing UV—B damage. A fifteen days experiment was designed to study moss (Bryum argenteum) and lichen (Umbilicaria aprina) under natural UV—B exposure and under UV filter frames at the Maitri region of Schirmacher oasis, East Antarctica. Changes in UV absorbing compounds, phenolics, carotenoids and chlorophyll content were studied for continuous fifteen days and significant changes were observed in the UV exposed plants of B. argenteum and U. aprina. The change in the UV absorbing compounds was more significant in B. argenteum (P<0.0001) than U. aprina (P<0.0002). The change in phenolic contents and total carotenoid content was significant (P<0.0001) in both B. argenteum and lichen U. aprina indicating that the increase in UV absorbing compounds, phenolic contents and total carotenoid content act as a protective mechanism against the deleterious effect of UV—B radiations.

  2. Aerosol radiative effects in the ultraviolet, visible, and near-infrared spectral ranges using long-term aerosol data series over the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Mateos, D.; Antón, M.; Toledano, C.; Cachorro, V. E.; Alados-Arboledas, L.; Sorribas, M.; Costa, M. J.; Baldasano, J. M.

    2014-04-01

    A better understanding of the aerosol radiative properties is a crucial challenge for climate change studies. This study aims to provide a complete characterization of aerosol radiative effects in different spectral ranges within the shortwave (SW) solar spectrum. For this purpose, long-term datasets of aerosol properties from six AERONET stations located in the Iberian Peninsula (Southwestern Europe) are analyzed in term of climatology characterization and trends. Aerosol information is used as input to the libRadtran model in order to determine the aerosol radiative effect at the surface in the ultraviolet (AREUV), visible (AREVIS), near-infrared (ARENIR), and the entire SW range (ARESW) under cloud-free conditions. Over the whole Iberian Peninsula, aerosol radiative effects in the different spectral ranges are: -1.1 < AREUV < -0.7 W m-2, -5.7 < AREVIS < -3.8 W m-2, -2.8 < ARENIR < -1.7 W m-2, and -9.5 < ARESW < -6.1 W m-2. The four variables showed positive statistically significant trends between 2004 and 2012, e.g., ARESW increased +3.6 W m-2 per decade. This fact is linked to the decrease in the aerosol load, which presents a trend of -0.04 per unit of aerosol optical depth at 500 nm per decade, hence a reduction of aerosol effect on solar radiation at the surface is seen. Monthly means of ARE show a seasonal pattern with larger values in spring and summer. The aerosol forcing efficiency (AFE), ARE per unit of aerosol optical depth, is also evaluated in the four spectral ranges. AFE exhibits a dependence on single scattering albedo and a weaker one on Ångström exponent. AFE is larger (in absolute value) for small and absorbing particles. The contributions of the UV, VIS, and NIR ranges to the SW efficiency vary with the aerosol types. Aerosol size determines the fractions of AFEVIS/AFESW and AFENIR/AFESW. VIS range is the dominant region for all types, although non-absorbing large particles cause a more equal contribution of VIS and NIR intervals. The AFEUV

  3. Dependence of the absorption of pulsed CO{sub 2}-laser radiation by silane on wavenumber, fluence, pulse duration, temperature, optical path length, and pressure of absorbing and nonabsorbing gases

    SciTech Connect

    Blazejowski, J.; Gruzdiewa, L.; Rulewski, J.; Lampe, F.W.

    1995-05-15

    The absorption of three lines [{ital P}(20), 944.2 cm{sup {minus}1}; {ital P}(14), 949.2 cm{sup {minus}1}; and {ital R}(24), 978.5 cm{sup {minus}1}] of the pulsed CO{sub 2} laser (00{sup 0}1--10{sup 0}0 transition) by SiH{sub 4} was measured at various pulse energy, pulse duration, temperature, optical path length, and pressure of the compound and nonabsorbing foreign gases. In addition, low intensity infrared absorption spectrum of silane was compared with high intensity absorption characteristics for all lines of the pulsed CO{sub 2} laser. The experimental dependencies show deviations from the phenomenological Beer--Lambert law which can be considered as arising from the high intensity of an incident radiation and collisions of absorbing molecules with surroundings. These effects were included into the expression, being an extended form of the Beer--Lambert law, which reasonably approximates all experimental data. The results, except for extending knowledge on the interaction of a high power laser radiation with matter, can help understanding and planning processes leading to preparation of silicon-containing technologically important materials.

  4. Physically based parameterizations of the short-wave radiative characteristics of weakly absorbing optically thick media: application to liquid-water clouds.

    PubMed

    Kokhanovsky, A A; Nakajima, T; Zege, E P

    1998-07-20

    We propose the physically based parameterization of the radiative characteristics of liquid-water clouds as functions of the wavelength, effective radius, and refractive index of particles, liquid-water path, ground albedo, and solar and observation angles. The formulas obtained are based on the approximate analytical solutions of the radiative transfer equation for optically thick, weakly absorbing layers and the geometrical optics approximation for local optical characteristics of cloud media. The accuracy of the approximate formulas was studied with an exact radiative transfer code. The relative error of the approximate formula for the reflection function at nadir observations was less then 15% for an optical thickness larger than 10 and a single-scattering albedo larger than 0.95.

  5. Evolution of structure and infrared radiation properties for ferrite-based amorphous coating

    NASA Astrophysics Data System (ADS)

    Lu, Lei; Fan, Xi'an; Zhang, Jianyi; Hu, Xiaoming; Li, Guangqiang; Zhang, Zhan

    2014-10-01

    The ferrite-based amorphous coatings with high infrared radiation properties have been successfully prepared on the surface of carbon steel substrate by plasma spraying process. The phase, morphology, microstructure, thermal behavior and infrared emissivity were determined by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and infrared spectroscopy. The prepared coating could keep amorphous structure when the ambient temperature was below 700 °C and it would crystallize gradually with further increasing the temperature. The amorphous structure is confirmed to be constructive for improving the emissivity of ferrite-based coatings, especially in the 3-8 μm band. The emissivity of the amorphous coating obtained by plasma spraying was over 0.8 in 3-8 μm band at 800 °C, which was higher than that of the coating with same composition prepared by conventional brushing method. The excellent thermal shock resistance of the coatings makes them to be good candidates for sensible energy-saving materials, which could work for long term at 1000 °C.

  6. Broadband near-field infrared spectromicroscopy using photothermal probes and synchrotron radiation.

    PubMed

    Donaldson, Paul M; Kelley, Chris S; Frogley, Mark D; Filik, Jacob; Wehbe, Katia; Cinque, Gianfelice

    2016-02-01

    In this paper, we experimentally demonstrate the use of infrared synchrotron radiation (IR-SR) as a broadband source for photothermal near-field infrared spectroscopy. We assess two methods of signal transduction; cantilever resonant thermal expansion and scanning thermal microscopy. By means of rapid mechanical chopping (50-150 kHz), we modulate the IR-SR at rates matching the contact resonance frequencies of atomic force microscope (AFM) cantilevers, allowing us to record interferograms yielding Fourier transform infrared (FT-IR) photothermal absorption spectra of polystyrene and cyanoacrylate films. Complementary offline measurements using a mechanically chopped CW IR laser confirmed that the resonant thermal expansion IR-SR measurements were below the diffraction limit, with a spatial resolution better than 500 nm achieved at a wavelength of 6 μm, i.e. λ/12 for the samples studied. Despite achieving the highest signal to noise so far for a scanning thermal microscopy measurement under conditions approaching near-field (dictated by thermal diffusion), the IR-SR resonant photothermal expansion FT-IR spectra measured were significantly higher in signal to noise in comparison with the scanning thermal data.

  7. Infrared Heater Used in Qualification Testing of International Space Station Radiators

    NASA Technical Reports Server (NTRS)

    Ziemke, Robert A.

    2004-01-01

    Two heat rejection radiator systems for the International Space Station (ISS) have undergone thermal vacuum qualification testing at the NASA Glenn Research Center (GRC), Plum Brook Station, Sandusky, Ohio. The testing was performed in the Space Power Facility (SPF), the largest thermal vacuum chamber in the world. The heat rejection system radiator was tested first; it removes heat from the ISS crew living quarters. The second system tested was the photovoltaic radiator (PVR), which rejects heat from the ISS photovoltaic arrays and the electrical power-conditioning equipment. The testing included thermal cycling, hot- and cold-soaked deployments, thermal gradient deployments, verification of the onboard heater controls, and for the PVR, thermal performance tests with ammonia flow. Both radiator systems are orbital replacement units for ease of replacement on the ISS. One key to the success of these tests was the performance of the infrared heater system. It was used in conjunction with a gaseous-nitrogen-cooled cryoshroud in the SPF vacuum chamber to achieve the required thermal vacuum conditions for the qualification tests. The heater, which was designed specifically for these tests, was highly successful and easily met the test requirements. This report discusses the heating requirements, the heater design features, the design approach, and the mathematical basis of the design.

  8. Time Resolved Detection of Infrared Synchrotron Radiation at DAΦNE

    NASA Astrophysics Data System (ADS)

    Bocci, A.; Marcelli, A.; Pace, E.; Drago, A.; Piccinini, M.; Guidi, M. Cestelli; Sali, D.; Morini, P.; Piotrowski, J.

    2007-01-01

    Synchrotron radiation is characterized by a very wide spectral emission from IR to X-ray wavelengths and a pulsed structure that is a function of the source time structure. In a storage ring, the typical temporal distance between two bunches, whose duration is a few hundreds of picoseconds, is on the nanosecond scale. Therefore, synchrotron radiation sources are a very powerful tools to perform time-resolved experiments that however need extremely fast detectors. Uncooled IR devices optimized for the mid-IR range with sub-nanosecond response time, are now available and can be used for fast detection of intense IR sources such as synchrotron radiation storage rings. We present here different measurements of the pulsed synchrotron radiation emission at DAΦNE (Double Annular Φ-factory for Nice Experiments), the collider of the Laboratori Nazionali of Frascati (LNF) of the Istituto Nazionale di Fisica Nucleare (INFN), performed with very fast uncooled infrared detectors with a time resolution of a few hundreds of picoseconds. We resolved the emission time structure of the electron bunches of the DAΦNE collider when it works in a normal condition for high energy physics experiments with both photovoltaic and photoconductive detectors. Such a technology should pave the way to new diagnostic methods in storage rings, monitoring also source instabilities and bunch dynamics.

  9. Mesoscopic modeling of the response of human dental enamel to mid-infrared radiation

    NASA Astrophysics Data System (ADS)

    Vila Verde, Ana; Ramos, Marta; Stoneham, A. M.

    2006-03-01

    Ablation of human dental enamel, a composite biomaterial with water pores, is of significant importance in minimally invasive laser dentistry but progress in the area is hampered by the lack of optimal laser parameters. We use mesoscopic finite element models of this material to study its response to mid-infrared radiation. Our results indicate that the cost-effective, off-the-shelf CO2 laser at λ = 10.6 μm may in fact ablate enamel precisely, reproducibly and with limited unwanted side effects such as cracking or heating, provided that a pulse duration of 10 μs is used. Furthermore, our results also indicate that the Er:YAG laser (λ = 2.94 μm), currently popular for laser dentistry, may in fact cause unwanted deep cracking in the enamel when regions with unusually high water content are irradiated, and also provide an explanation for the large range of ablation threshold values observed for this material. The model may be easily adapted to study the response of any composite material to infrared radiation and thus may be useful for the scientific community.

  10. Middle infrared radiation induces G2/M cell cycle arrest in A549 lung cancer cells.

    PubMed

    Chang, Hsin-Yi; Shih, Meng-Her; Huang, Hsuan-Cheng; Tsai, Shang-Ru; Juan, Hsueh-Fen; Lee, Si-Chen

    2013-01-01

    There were studies investigating the effects of broadband infrared radiation (IR) on cancer cell, while the influences of middle-infrared radiation (MIR) are still unknown. In this study, a MIR emitter with emission wavelength band in the 3-5 µm region was developed to irradiate A549 lung adenocarcinoma cells. It was found that MIR exposure inhibited cell proliferation and induced morphological changes by altering the cellular distribution of cytoskeletal components. Using quantitative PCR, we found that MIR promoted the expression levels of ATM (ataxia telangiectasia mutated), ATR (ataxia-telangiectasia and Rad3-related and Rad3-related), TP53 (tumor protein p53), p21 (CDKN1A, cyclin-dependent kinase inhibitor 1A) and GADD45 (growth arrest and DNA-damage inducible), but decreased the expression levels of cyclin B coding genes, CCNB1 and CCNB2, as well as CDK1 (Cyclin-dependent kinase 1). The reduction of protein expression levels of CDC25C, cyclin B1 and the phosphorylation of CDK1 at Thr-161 altogether suggest G(2)/M arrest occurred in A549 cells by MIR. DNA repair foci formation of DNA double-strand breaks (DSB) marker γ-H2AX and sensor 53BP1 was induced by MIR treatment, it implies the MIR induced G(2)/M cell cycle arrest resulted from DSB. This study illustrates a potential role for the use of MIR in lung cancer therapy by initiating DSB and blocking cell cycle progression.

  11. Cosmic ray modulation of infra-red radiation in the atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, Karen; Lockwood, Michael

    2013-04-01

    Cosmic rays produce small charged clusters, known as molecular cluster ions, as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by charged clusters has not hitherto been observed. Here we describe results from an atmospheric experiment where a thermopile filter radiometer tuned to a 9.15μm absorption band, already associated with infra-red absorption of molecular cluster ions, was used to monitor changes following events identified by a cosmic ray telescope sensitive to high energy (>400MeV) particles, principally muons at the surface. The change in longwave radiation in this absorption band due to molecular cluster ions is 7 mWm-2 for each event recorded by the cosmic ray telescope. The integrated atmospheric energy change for each event is 1.9 Jm-2, whereas the energy density of a typical air shower (40m radius from a 10GeV primary) is estimated to be 10-13 Jm-2, representing a direct amplification factor of 1012. This infra-red absorption from molecular cluster-ions is expected to occur continuously and globally, but calculations suggest that it has only a small effect on climate.

  12. Infrared Radiative Properties of Yttria-Stabilized Zirconia Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Eldridge, Jeff I.; Spuckler, Charles M.; Street, Ken W.; Markham, Jim R.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    The infrared (IR) transmittance and reflectance of translucent thermal barrier coatings (TBCs) have important implications for both the performance of these coatings as radiation barriers and emitters as well as affecting measurements of TBC thermal conductivity, especially as TBCs are being pushed to higher temperatures. In this paper, the infrared spectral directional-hemispherical transmittance and reflectance of plasma-sprayed 8wt% yttria-stabilized zirconia (8YSZ) TBCs are reported. These measurements are compared to those for single crystal YSZ specimens to show the effects of the plasma-sprayed coating microstructure. It is shown that the coatings exhibit negligible absorption at wavelengths up to about 5 micrometers, and that internal scattering rather than surface reflections dominates the hemispherical reflectance. The translucent nature of the 8YSZ TBCs results in the absorptance/emittance and reflectance of TBC-coated substrates depending on the TBC thickness, microstructure, as well as the radiative properties of the underlying substrate. The effects of these properties on TBC measurements and performance are discussed.

  13. Anomalous Polarization May Improve Infrared Detectors

    NASA Technical Reports Server (NTRS)

    Yang, Chan-Lon; Pan, Dee-Son

    1990-01-01

    New configurations proposed for quantum-well devices. Simplifies alignment, increases sensitivity, and opens up more possibilities in design of quantum-well detectors of infrared radiation. In detector made according to proposed concept, light incident broadside on front surface absorbed. No special waveguide structures required.

  14. [Research on infrared radiation characteristics of skin covering two acupuncture points in the hand and forearm, NeiGuan and LaoGong points].

    PubMed

    Wang, Zhen; Yu, Wenlong; Cui, Han; Shi, Huafeng; Jin, Lei

    2013-06-01

    In order to research the infrared radiation characteristics of the skin covering Traditional Chinese acupuncture points, which are NeiGuan in the forearm and LaoGong in the center of the palm, we detected continuously the infrared radiation spectra of the human body surface by using Fourier Transform Infrared Spectroscopy. The experimental results showed that firstly, the differences of the infrared radiation spectra of the human body surface were obvious between individuals. Secondly, the infrared radiation intensity of the human body surface changed with time changing. The infrared radiation intensity in two special wavelength ranges (wavelengths from 6. 79 microm to 6. 85 microm and from 13. 6 microm to 14. 0 microm) changed much more than that in other ranges obviously. Thirdly, the proportions of the infrared radiation spectra changed, which were calculated from the spectra of two different aupuncture points, were same in these two special wavelength ranges, but their magnitude changes were different. These results suggested that the infrared radiation of acupuncture points have the same biological basis, and the mechanism of the infrared radiation in these two special wavelength ranges is different from other tissue heat radiation.

  15. Structural changes caused by radiation-induced reduction and radiolysis: the effect of X-ray absorbed dose in a fungal multicopper oxidase

    PubMed Central

    De la Mora, Eugenio; Lovett, Janet E.; Blanford, Christopher F.; Garman, Elspeth F.; Valderrama, Brenda; Rudino-Pinera, Enrique

    2012-01-01

    X-ray radiation induces two main effects at metal centres contained in protein crystals: radiation-induced reduction and radiolysis and a resulting decrease in metal occupancy. In blue multicopper oxidases (BMCOs), the geometry of the active centres and the metal-to-ligand distances change depending on the oxidation states of the Cu atoms, suggesting that these alterations are catalytically relevant to the binding, activation and reduction of O2. In this work, the X-ray-determined three-dimensional structure of laccase from the basidiomycete Coriolopsis gallica (Cg L), a high catalytic potential BMCO, is described. By combining spectroscopic techniques (UV–Vis, EPR and XAS) and X-ray crystallography, structural changes at and around the active copper centres were related to pH and absorbed X-­ray dose (energy deposited per unit mass). Depletion of two of the four active Cu atoms as well as low occupancies of the remaining Cu atoms, together with different conformations of the metal centres, were observed at both acidic pH and high absorbed dose, correlating with more reduced states of the active coppers. These observations provide additional evidence to support the role of flexibility of copper sites during O2 reduction. This study supports previous observations indicating that interpretations regarding redox state and metal coordination need to take radiation effects explicitly into account. PMID:22525754

  16. Extrapolation algorithm to Forecast the Dynamics of Accumulation of the Absorbed Dose at the International Space Station, according to the Radiation Monitoring System Data

    NASA Astrophysics Data System (ADS)

    Lishnevskii, Andrey

    The ISS service module is equipped with the radiation monitoring system (RMS) which provides data for the daily estimation of the radiation environment on board the station. The sensitive elements of the RMS are silicon semiconductor detectors and ionization chambers. The data obtained in quiet radiation environment allowed to determine the contribution to the absorbed radiation dose due to galactic cosmic rays and the Earth’s inner radiation belt. The corresponding analysis was conducted for the 2005-2011 period. As a result empirical relations were obtained allowing to calculate the dose for one crossing of the area of the South Atlantic Anomaly. The initial parameters for the calculation are longitude and altitude on which the ISS trajectory crosses this area. The obtained empirical relations allowed to develop a simple calculation algorithm for the short-term forecasting of the dynamics of accumulation of the radiation dose at the ISS which is based on the assumption that the current level of contribution to the daily dose of galactic cosmic rays and the structure of the Earth’s inner radiation belt at the station flight altitude remains unchanged within a few days. The results of the analysis of the ISS RMS data which was conducted using the developed calculation algorithm for the period from 2005 to 2011 (the period in which solar cycle 23 ended and solar cycle 24 began) showed the possibility to implement a short-term (1-2 days) forecast of the dynamics of accumulation of the dose on board the station with an acceptable error (of no more than 30 percent). Besides, the developed forecast algorithm for the growth phase of the 24th solar cycle (2011-2014) was verified. The algorithm developed for forecasting the radiation environment may be used to process and analyse the current RMS information when providing effective radiation safety for the ISS crew.

  17. The phase transition in VO2 probed using x-ray, visible and infrared radiations

    NASA Astrophysics Data System (ADS)

    Kumar, Suhas; Strachan, John Paul; Kilcoyne, A. L. David; Tyliszczak, Tolek; Pickett, Matthew D.; Santori, Charles; Gibson, Gary; Williams, R. Stanley

    2016-02-01

    Vanadium dioxide (VO2) is a model system that has been used to understand closely occurring multiband electronic (Mott) and structural (Peierls) transitions for over half a century due to continued scientific and technological interests. Among the many techniques used to study VO2, the most frequently used involve electromagnetic radiation as a probe. Understanding of the distinct physical information provided by different probing radiations is incomplete, mostly owing to the complicated nature of the phase transitions. Here, we use transmission of spatially averaged infrared (λ = 1.5 μm) and visible (λ = 500 nm) radiations followed by spectroscopy and nanoscale imaging using x-rays (λ = 2.25-2.38 nm) to probe the same VO2 sample while controlling the ambient temperature across its hysteretic phase transitions and monitoring its electrical resistance. We directly observed nanoscale puddles of distinct electronic and structural compositions during the transition. The two main results are that, during both heating and cooling, the transition of infrared and visible transmission occurs at significantly lower temperatures than the Mott transition, and the electronic (Mott) transition occurs before the structural (Peierls) transition in temperature. We use our data to provide insights into possible microphysical origins of the different transition characteristics. We highlight that it is important to understand these effects because small changes in the nature of the probe can yield quantitatively, and even qualitatively, different results when applied to a non-trivial multiband phase transition. Our results guide more judicious use of probe type and interpretation of the resulting data.

  18. Adding method of delta-four-stream spherical harmonic expansion approximation for infrared radiative transfer parameterization

    NASA Astrophysics Data System (ADS)

    Wu, Kun; Zhang, Feng; Min, Jinzhong; Yu, Qiu-Run; Wang, Xin-Yue; Ma, Leiming

    2016-09-01

    The adding method, which could calculate the infrared radiative transfer (IRT) in inhomogeneous atmosphere with multiple layers, has been applied to δ -four-stream discrete-ordinates method (DOM). This scheme is referred as δ -4DDA. However, there is a lack of application for adding method of δ -four-stream spherical harmonic expansion approximation (SHM) to solve infrared radiative transfer through multiple layers. In this paper, the adding method for δ -four-stream SHM (δ -4SDA) will be obtained and the accuracy of it will be evaluated as well. The result of δ -4SDA in an idealized medium with homogeneous optical property is significantly more accurate than that of the adding method for δ -two-stream DOM (δ -2DDA). The relative errors of δ -2DDA can be over 15% in thin optical depths for downward emissivity, while errors of δ -4SDA are bounded by 2%. However, the result of δ -4SDA is slightly less accurate than that of δ -4DDA. In a radiation model with realistic atmospheric profile considering gaseous transmission, the accuracy for heating rate of δ -4SDA is significantly superior than that of δ -2DDA, especially for the cloudy sky. The accuracy for heating rate of δ -4SDA is slightly less accurate than that of δ -4DDA under water cloud conditions, while it is superior than that of δ -4DDA in ice cloud cases. Beside, the computational efficiency of δ -4SDA is higher than that of δ -4DDA.

  19. 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)

  20. Radiation stability of visible and near-infrared optical and magneto-optical properties of terbium gallium garnet crystals.

    PubMed

    Geist, Brian; Ronningen, Reginald; Stolz, Andreas; Bollen, Georg; Kochergin, Vladimir

    2015-04-01

    Perspectives of terbium gallium garnet, Tb₃Ga₅O₁₂ (TGG), for the use of radiation-resistant high magnetic field sensing are studied. Long-term radiation stability of the TGG crystals was analyzed by comparing the optical and magneto-optical properties of a radiation-exposed TGG crystal (equivalent neutron dose 6.3×10¹³ n/cm²) to the properties of TGG control samples. Simulations were also performed to predict radiation damage mechanisms in the TGG crystal. Radiation-induced increase in the absorbance at shorter wavelengths was observed as well as a reduction in the Faraday effect while no degradation of magneto-optical effect was observed when at wavelengths above 600 nm. This suggests that TGG crystal would be a good candidate for use in magneto-optical radiation-resistant magnetic field sensors. PMID:25967201

  1. Radiation stability of visible and near-infrared optical and magneto-optical properties of terbium gallium garnet crystals.

    PubMed

    Geist, Brian; Ronningen, Reginald; Stolz, Andreas; Bollen, Georg; Kochergin, Vladimir

    2015-04-01

    Perspectives of terbium gallium garnet, Tb₃Ga₅O₁₂ (TGG), for the use of radiation-resistant high magnetic field sensing are studied. Long-term radiation stability of the TGG crystals was analyzed by comparing the optical and magneto-optical properties of a radiation-exposed TGG crystal (equivalent neutron dose 6.3×10¹³ n/cm²) to the properties of TGG control samples. Simulations were also performed to predict radiation damage mechanisms in the TGG crystal. Radiation-induced increase in the absorbance at shorter wavelengths was observed as well as a reduction in the Faraday effect while no degradation of magneto-optical effect was observed when at wavelengths above 600 nm. This suggests that TGG crystal would be a good candidate for use in magneto-optical radiation-resistant magnetic field sensors.

  2. An accurate parameterization of the infrared radiative properties of cirrus clouds for climate models

    SciTech Connect

    Fu, Q.; Sun, W.B.; Yang, P.

    1998-09-01

    An accurate parameterization is presented for the infrared radiative properties of cirrus clouds. For the single-scattering calculations, a composite scheme is developed for randomly oriented hexagonal ice crystals by comparing results from Mie theory, anomalous diffraction theory (ADT), the geometric optics method (GOM), and the finite-difference time domain technique. This scheme employs a linear combination of single-scattering properties from the Mie theory, ADT, and GOM, which is accurate for a wide range of size parameters. Following the approach of Q. Fu, the extinction coefficient, absorption coefficient, and asymmetry factor are parameterized as functions of the cloud ice water content and generalized effective size (D{sub ge}). The present parameterization of the single-scattering properties of cirrus clouds is validated by examining the bulk radiative properties for a wide range of atmospheric conditions. Compared with reference results, the typical relative error in emissivity due to the parameterization is {approximately}2.2%. The accuracy of this parameterization guarantees its reliability in applications to climate models. The present parameterization complements the scheme for the solar radiative properties of cirrus clouds developed by Q. Fu for use in numerical models.

  3. The effects of narrow-band middle infrared radiation in enhancing the antitumor activity of paclitaxel.

    PubMed

    Tsai, Shang-Ru; Sheu, Bor-Ching; Huang, Pei-Shen; Lee, Si-Chen

    2016-01-01

    Paclitaxel is used as an adjuvant to enhance the effectiveness of ionization radiation therapy; however, high-energy radiation often damages the healthy cells surrounding cancer cells. Low-energy, middle-infrared radiation (MIR) has been shown to prevent tissue damage, and recent studies have begun combining MIR with paclitaxel. However, the cytotoxic effects of this treatment combination remain unclear, and the mechanism underlying its effects on HeLa cells has yet to be elucidated. This study investigated the effectiveness of treating HeLa human cervical cancer cells with a combination of paclitaxel for 48 h in conjunction with narrow-band MIR from 3.0 to 5.0 μm. This combined treatment significantly inhibited the growth of HeLa cells. Specifically, results from Annexin V-FITC/PI apoptosis detection and cell mitochondrial membrane potential analyses revealed an increase in apoptotic cell death and a collapse of mitochondrial membrane potential. One possible mechanism underlying cellular apoptosis is an increase in oxidative stress. These preliminary findings provide evidence to support the combination of narrow-band MIR with paclitaxel as an alternative approach in the treatment of human cervical cancer.

  4. An Accurate Parameterization of the Infrared Radiative Properties of Cirrus Clouds for Climate Models.

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Yang, Ping; Sun, W. B.

    1998-09-01

    An accurate parameterization is presented for the infrared radiative properties of cirrus clouds. For the single-scattering calculations, a composite scheme is developed for randomly oriented hexagonal ice crystals by comparing results from Mie theory, anomalous diffraction theory (ADT), the geometric optics method (GOM), and the finite-difference time domain technique. This scheme employs a linear combination of single-scattering properties from the Mie theory, ADT, and GOM, which is accurate for a wide range of size parameters. Following the approach of Q. Fu, the extinction coefficient, absorption coefficient, and asymmetry factor are parameterized as functions of the cloud ice water content and generalized effective size (Dge). The present parameterization of the single-scattering properties of cirrus clouds is validated by examining the bulk radiative properties for a wide range of atmospheric conditions. Compared with reference results, the typical relative error in emissivity due to the parameterization is 2.2%. The accuracy of this parameterization guarantees its reliability in applications to climate models. The present parameterization complements the scheme for the solar radiative properties of cirrus clouds developed by Q. Fu for use in numerical models.

  5. The effect of multiple scattering on radiative transmission measurements in a two-dimensional absorbing-scattering medium

    NASA Astrophysics Data System (ADS)

    Yuen, W. W.; Dunaway, W.

    1985-06-01

    A successive approximation procedure is developed to determine the scattering correction to the Beer-Lambert law in the evaluation of geometric mean transmittance in a general multi-dimensional absorbing and scattering medium. At each step of the approximation, the evaluation of an upper and lower bound of the scattering correction requires only a single integral over the volume of the scattering medium. This represents a great reduction in mathematical complexity compared to the direct numerical approach. First-order results for a two-dimensional rectangular absorbing and scattering medium are presented. They are shown to be quite accurate in the optically thin limit and useful for engineering application for media with arbitrary optical thickness. Some interesting conclusions concerning the qualitative physical behavior of the scattering correction are also generated.

  6. Stable 1.25 watts CW far infrared laser radiation at the 119 micron methanol line

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam; Pickett, Herbert M.

    1987-01-01

    Far-infrared CW radiation of 1.25 watts has been obtained at the 119 micron methanol line with a CO2 pump power of 125 watts, and the maximum frequency fluctuation of the free running laser is measured to be less than + or - 100 kHz per hour. Reflecting optics have been used, when possible, to minimize CO2 degradation, and the frequency stability is ensured by cooling the input and output couplers. The input and output assemblies within the lasing medium are enclosed to minimize the external effects on the cavity length and to eliminate the mechanical instabilities associated with the use of bellows. The vibrational bottle-neck is broken by cooling the resonator wall to 5 deg and adding He as the buffer gas.

  7. Slot Antenna Coupled Thin-Film Warm Carrier Far-Infrared Radiation Detectors

    NASA Astrophysics Data System (ADS)

    Yasuoka, Yoshizumi; Suzuki, Kenji

    Slot antenna coupled thin-film warm carrier devices were fabricated, and the detection properties were investigated at 94 and 700 GHz. Two-dimensional 8 × 3 slot antenna arrays fed by a coplanar waveguide were used as the antennas. The thin-film antennas were fabricated with a photolithographic method, and the warm carrier detectors, which have the contact area of 8 × 10-10 cm2, were fabricated with an electron beam lithographic method. The experimental results indicate that the fabricated devices receive the far-infrared radiation with antenna and rectified it with non-linear I-V characteristic. By changing the antenna from the single slot antenna to the two-dimensional 8 × 3 slot antenna array, the detected sensitivity improved by 11 dB.

  8. Bonding and electronic states of boron in silicon nanowires characterized by an infrared synchrotron radiation beam.

    PubMed

    Fukata, N; Jevasuwan, W; Ikemoto, Y; Moriwaki, T

    2015-04-28

    The infrared synchrotron radiation (IR-SR) beamline of SPring-8 as an IR light source was applied to characterize boron (B) atoms in silicon nanowires (SiNWs). The use of an IR-SR beam with much higher brilliance than conventional IR light sources and a wide range of wavenumbers from visible to far IR regions made it possible to detect a local vibrational mode of B in SiNWs. The use of this technique has also made it possible to detect other IR peaks related to transitions of a bound hole from the ground state of a B acceptor atom to excited states, clarifying the electronic state of B acceptors in SiNWs.

  9. Structural changes caused by radiation-induced reduction and radiolysis: the effect of X-ray absorbed dose in a fungal multicopper oxidase

    SciTech Connect

    De la Mora, Eugenio; Lovett, Janet E.; Blanford, Christopher F.; Garman, Elspeth F.; Valderrama, Brenda; Rudino-Pinera, Enrique

    2012-05-01

    Radiation-induced reduction, radiolysis of copper sites and the effect of pH value together with the concomitant geometrical distortions of the active centres were analysed in several fungal (C. gallica) laccase structures collected at cryotemperature. This study emphasizes the importance of careful interpretation when the crystallographic structure of a metalloprotein is described. X-ray radiation induces two main effects at metal centres contained in protein crystals: radiation-induced reduction and radiolysis and a resulting decrease in metal occupancy. In blue multicopper oxidases (BMCOs), the geometry of the active centres and the metal-to-ligand distances change depending on the oxidation states of the Cu atoms, suggesting that these alterations are catalytically relevant to the binding, activation and reduction of O{sub 2}. In this work, the X-ray-determined three-dimensional structure of laccase from the basidiomycete Coriolopsis gallica (Cg L), a high catalytic potential BMCO, is described. By combining spectroscopic techniques (UV–Vis, EPR and XAS) and X-ray crystallography, structural changes at and around the active copper centres were related to pH and absorbed X-ray dose (energy deposited per unit mass). Depletion of two of the four active Cu atoms as well as low occupancies of the remaining Cu atoms, together with different conformations of the metal centres, were observed at both acidic pH and high absorbed dose, correlating with more reduced states of the active coppers. These observations provide additional evidence to support the role of flexibility of copper sites during O{sub 2} reduction. This study supports previous observations indicating that interpretations regarding redox state and metal coordination need to take radiation effects explicitly into account.

  10. Application and possible mechanisms of combining LLLT (low level laser therapy), infrared hyperthermia and ionizing radiation in the treatment of cancer

    NASA Astrophysics Data System (ADS)

    Abraham, Edward H.; Woo, Van H.; Harlin-Jones, Cheryl; Heselich, Anja; Frohns, Florian

    2014-02-01

    Benefit of concomitant infrared hyperthermia and low level laser therapy and ionizing radiation is evaluated in this study. The purpose/objectives: presentation with locally advanced bulky superficial tumors is clinically challenging. To enhance the efficacy of chemotherapy and IMRT (intensity-modulated radiation therapy) and/or electron beam therapy we have developed an inexpensive and clinically effective infrared hyperthermia approach that combines black-body infrared radiation with halogen spectrum radiation and discrete wave length infrared clinical lasers LLLT. The goal is to produce a composite spectrum extending from the far infrared to near infrared and portions of the visible spectrum with discrete penetrating wavelengths generated by the clinical infrared lasers with frequencies of 810 nm and/or 830 nm. The composite spectrum from these sources is applied before and after radiation therapy. We monitor the surface and in some cases deeper temperatures with thermal probes, but use an array of surface probes as the limiting safe thermal constraint in patient treatment while at the same time maximizing infrared entry to deeper tissue layers. Fever-grade infrared hyperthermia is produced in the first centimeters while non-thermal infrared effects act at deeper tissue layers. The combination of these effects with ionizing radiation leads to improved tumor control in many cancers.

  11. The infrared radiation temperature characteristic of acupoints of mammary gland hyperplasia patients.

    PubMed

    Zheng, Juanjuan; Zhao, Yi; Wang, Yafang; Hu, Shengfang; Lu, Ping; Shen, Xueyong

    2013-01-01

    Objective. To ascertain pathological information on hyperplasia of mammary glands (HMG) of patients via the infrared radiation temperature of acupoints. Method. Patients with HMG and healthy controls were tested using an infrared thermal imager. Results. In controls, no significant difference in temperature was observed between points with the same name (P > 0.05). The temperature of all tested points was found to be higher in the group with HMG than in that of the healthy controls, except for the left and right Zusanli (ST36). The temperature of the right Rugen (ST18), Guanyuan (CV4), Qihai (CV6), and Hegu (LI4) reached a statistically significant heightened level (P = 0.046~P < 0.001). The temperature of the Zusanli (ST36) and Hegu (LI4) present on the right side was significantly higher than that of the left (P = 0.001 and P = 0.004, resp.), while the temperature of the left Youmen (KI21) was significantly higher than that of the right (P = 0.008). Conclusion. The temperature of the bilateral acupoints in healthy controls was symmetrical, and the raised temperatures observed of the Rugen (ST18), Guanyuan (CV4), Qihai (CV6), and Hegu (LI4) acupoints of HMG patients and the imbalance of the temperature of the bilateral acupoints Zusanli (ST36), Youmen (KI21), and Hegu (LI4) carried special pathological information about HMG disease. PMID:24327822

  12. Q-switching of mid-infrared Er:YAG laser and its radiation delivery system

    NASA Astrophysics Data System (ADS)

    Jelinkova, Helena; Koranda, Petr; Nemec, Michal; Sulc, Jan; Cech, Miroslav; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji

    2004-09-01

    Q-switching of mid-infrared Er:YAG laser was obtained with an electro-optical shutter. For that the LiNbO3 Pockels cell was used in transversal quarter-wave arrangement with the Brewster angle cut faces used as a polarizer. Parameters and dependences of this Q-switched system were investigated, i.e. a pulse length and generated pulse energy, delay between switching of flashlamp and Q-switch circuit, high voltage applied on Pockels cell were measured and optimized. The resulted giant pulse length and energy was 60 ns and 55 mJ, respectively. This generated pulse was obtained for the applied voltage around 1.4 kV and for the optimum delay value 450 us. Problem of mid-infrared giant pulse delivery, which is needed for various technological applications, was solved by a specially designed cyclic olefin polymer coated silver hollow glass (COP/Ag) waveguide. Parameters of this waveguide were: diameter 700/850 um and length 1 m. The measured transmission was 74 % which corresponded to delivered intensity 86 MW/cm2. Q-switched Er:YAG laser radiation in connection with this special delivery system gives a possibility of the surgical treatment in many medicine branches, for example ophthalmology, urology or dentistry.

  13. Simultaneous heat and mass transfer in polymer solutions exposed to intermittent infrared radiation heating

    SciTech Connect

    Chen, J.J.; Lin, J.D.

    1998-06-01

    Drying is one of the essential steps in a number of industrial applications, such as the preserving of food and the drying of paint, pulp, and paper. The quality of paper tubes is significantly affected by the heat and mass transfer process. The drying of polymer solution plays a crucial role in the manufacturer of photographic film, synthetic fibers, adhesives, and a variety of other polymeric products. During drying of wet materials, simultaneous heat and mass transfer occurs both inside the medium and in the boundary layer of the drying agent. Drying is one of the most energy-consuming processes in the industrial sector and can also be very time consuming as, for example, in conventional convective drying by hot air, while minimum cost and energy consumption and maximum product quality are among the main concerns in industry today. Here, a theoretical study is performed that describes heat transfer and moisture variation while a polymer solution is exposed to high-intensity infrared radiation flux and/or an airflow. While the intermittent heating is considered, the authors investigate the influences of various radiation and convection parameters on the transfer of heat and moisture variation of coated layers on an optically thick substrate. During the tempering stage in the intermittent heating process, the convective mass transfer is included to simulate the ambient air in reality. The effects of radiation and convection parameters on the transfer processes are presented in terms of the rate of water content removal, heat transfer, and moisture distributions. Numerical results show that the rate of water removal from the polymer solution is dominated by both the adsorbed radiative heat energy and the distributions of water mass fraction in the polymer solution.

  14. Jet-Cooled Spectroscopy on the Ailes Infrared Beamline of the Synchrotron Radiation Facility Soleil

    NASA Astrophysics Data System (ADS)

    Georges, Robert

    2015-06-01

    The Advanced Infrared Line Exploited for Spectroscopy (AILES) extracts the bright far infrared (FIR) synchrotron continuum of the third generation radiation facility SOLEIL. This beamline is equipped with a high resolution (10-3 cm-1) Bruker IFS125 Fourier transform spectrometer which can be operated in the FIR but also in the mid and near infrared by using its internal conventional sources. The jet-AILES consortium (IPR, PhLAM, MONARIS, SOLEIL) has implemented a supersonic-jet apparatus on the beamline to record absorption spectra at very low temperature (5-50 K) and in highly supersaturated gaseous conditions. Heatable slit-nozzles of various lengths and widths are used to set properly the stagnation conditions. A mechanical pumping (roots pumps) was preferred for its ability to evacuate important mass flow rates and therefore to boost the experimental sensitivity of the set-up, the counterpart being a non-negligible consumption of both carrier (argon, helium or nitrogen) and spectroscopic gases. Various molecular systems were investigated up to now using the Jet-AILES apparatus. The very low temperature achieved in the gas expansion was either used to simplify the rotation-vibration structure of monomers, such as SF6, CF4 or naphthalene, or to stabilize the formation of weakly bonded molecular complexes such as the trimer of HF or the dimer of acetic acid. The nucleation of water vapor and the nuclear spin conversion of water were also investigated under free-jet conditions in the mid infrared. High-resolution spectroscopy and analysis of the νb{2} + νb{3} combination band of SF6 in a supersonic jet expansion. V. Boudon, P. Asselin, P. Soulard, M. Goubet, T. R. Huet, R. Georges, O. Pirali, P. Roy, Mol. Phys. 111, 2154-2162 (2013) The far infrared spectrum of naphthalene characterized by high resolution synchrotron FTIR spectroscopy and anharmonic DFT calculations. O. Pirali, M. Goubet, T.R. Huet, R. Georges, P. Soulard, P. Asselin, J. Courbe, P. Roy and M

  15. The expression revealing variation trend about radiation resistance of aromatic polymers serving in nuclear environment over absorbed dose

    NASA Astrophysics Data System (ADS)

    Lu, Shuangying; Hu, Huasi; Hu, Guang; Liu, Bin

    2015-03-01

    For polymeric materials applied in nuclear environment, the macroscopic properties usually remain unchanged after irradiation for several years or decades up to a threshold dose at which the deterioration of materials begins to take place. In this paper, the general radiation response of aromatic polymers is firstly reviewed and discussed. Then percolation theory is employed innovatively to elucidate the critical phenomenon over the service life for polymeric materials with high radiation resistance. For a better quantitative evaluation, a novel two-parameter radiation resistance model is proposed by the method of analogy between two nuclear-related phenomena. Six epoxy systems are employed from the published literatures to verify the novel model and the result shows that it is reliable and helpful in not only estimating the radiation damage over the service period but also multi-objective optimum design of polymeric materials.

  16. Metasurface Broadband Solar Absorber

    PubMed Central

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-01-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. PMID:26828999

  17. Metasurface Broadband Solar Absorber.

    PubMed

    Azad, Abul K; Kort-Kamp, Wilton J M; Sykora, Milan; Weisse-Bernstein, Nina R; Luk, Ting S; Taylor, Antoinette J; Dalvit, Diego A R; Chen, Hou-Tong

    2016-01-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure.

  18. Metasurface Broadband Solar Absorber

    DOE PAGES

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-02-01

    Here, we demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Moreover, our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributionsmore » to elucidate how the absorption occurs within the metasurface structure.« less

  19. Metasurface Broadband Solar Absorber.

    PubMed

    Azad, Abul K; Kort-Kamp, Wilton J M; Sykora, Milan; Weisse-Bernstein, Nina R; Luk, Ting S; Taylor, Antoinette J; Dalvit, Diego A R; Chen, Hou-Tong

    2016-01-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. PMID:26828999

  20. Nighttime Infrared radiative cooling and opacity inferred by REMS Ground Temperature Sensor Measurements

    NASA Astrophysics Data System (ADS)

    Martín-Torres, Javier; Paz Zorzano, María; Pla-García, Jorge; Rafkin, Scot; Lepinette, Alain; Sebastián, Eduardo; Gómez-Elvira, Javier; REMS Team

    2013-04-01

    Due to the low density of the Martian atmosphere, the temperature of the surface is controlled primarily by solar heating, and infrared cooling to the atmosphere and space, rather than heat exchange with the atmosphere. In the absence of solar radiation the infrared (IR) cooling, and then the nighttime surface temperatures, are directly controlled by soil termal inertia and atmospheric optical thickness (τ) at infrared wavelengths. Under non-wind conditions, and assuming no processes involving latent heat changes in the surface, for a particular site where the rover stands the main parameter controlling the IR cooling will be τ. The minimal ground temperature values at a fixed position may thus be used to detect local variations in the total dust/aerosols/cloud tickness. The Ground Temperature Sensor (GTS) and Air Temperature Sensor (ATS) in the Rover Environmental Monitoring Station (REMS) on board the Mars Science Laboratory (MSL) Curiosity rover provides hourly ground and air temperature measurements respectively. During the first 100 sols of operation of the rover, within the area of low thermal inertia, the minimal nightime ground temperatures reached values between 180 K and 190 K. For this season the expected frost point temperature is 200 K. Variations of up to 10 K have been observed associated with dust loading at Gale at the onset of the dust season. We will use these measurements together with line-by-line radiative transfer simulations using the Full Transfer By Optimized LINe-by-line (FUTBOLIN) code [Martín-Torres and Mlynczak, 2005] to estimate the IR atmospheric opacity and then dust/cloud coverage over the rover during the course of the MSL mission. Monitoring the dust loading and IR nightime cooling evolution during the dust season will allow for a better understanding of the influence of the atmosphere on the ground temperature and provide ground truth to models and orbiter measurements. References Martín-Torres, F. J. and M. G. Mlynczak

  1. Effect of Berry Size and Sodium Hydroxide Pretreatment on the Drying Characteristics of Blueberries under Infrared Radiation Heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research studied the effect on the drying characteristics of blueberries under infrared radiation (IR) heating of berry size and dipping pretreatment in hot sodium hydroxide (NaOH) solution. Changes in the microstructure and diffusion coefficient of the berries after the NaOH pretreatment were...

  2. Protective effect of infrared-A radiation against damage induced by UVB radiation in the melan-a cell line.

    PubMed

    Portantiolo Lettnin, Aline; Teixeira Santos Figueiredo Salgado, Mariana; Gonsalez Cruz, Camila; Manoel Rodrigues da Silva-Júnior, Flávio; Cunha Gonzalez, Vinícius; de Souza Votto, Ana Paula; Santos Trindade, Gilma; de Moraes Vaz Batista Filgueira, Daza

    2016-10-01

    The present work evaluated the infrared-A (IR-A) protective effect using a light-emitting diode (LED) lamp against the cytotoxic effects of ultraviolet B radiation (UVB). Effects on cell viability (Trypan blue assay), DNA damage (comet assay), lipid peroxidation (FOX method), reactive oxygen species production and antioxidant capacity were analyzed in melan-a, a non-tumoral murine melanocytic cell line. To define the doses used in the interaction experiments between IR-A+UVB, dose/response curves were made after exposure to IR-A or UVB. The IR-A dose chosen was 0.8J/cm(2) because this dose caused no significant inhibition of proliferation effects and viability decreased. For UVB exposure, a dose of 0.015J/cm(2), which showed a decrease in viable cell number by approximately 50% in relation to control until 72h, was selected. For IR-A+UVB, cell proliferation recovery was showed, decreasing DNA damage and lipid peroxide content when compared to UVB alone. Besides, the results obtained for ROS and antioxidant capacity showed that the protection observed was probably not related to decreased oxidative stress. In conclusion, non-thermal IR-A was capable of protecting the melan-a cells from UVB induced damage. PMID:27567083

  3. Protective effect of infrared-A radiation against damage induced by UVB radiation in the melan-a cell line.

    PubMed

    Portantiolo Lettnin, Aline; Teixeira Santos Figueiredo Salgado, Mariana; Gonsalez Cruz, Camila; Manoel Rodrigues da Silva-Júnior, Flávio; Cunha Gonzalez, Vinícius; de Souza Votto, Ana Paula; Santos Trindade, Gilma; de Moraes Vaz Batista Filgueira, Daza

    2016-10-01

    The present work evaluated the infrared-A (IR-A) protective effect using a light-emitting diode (LED) lamp against the cytotoxic effects of ultraviolet B radiation (UVB). Effects on cell viability (Trypan blue assay), DNA damage (comet assay), lipid peroxidation (FOX method), reactive oxygen species production and antioxidant capacity were analyzed in melan-a, a non-tumoral murine melanocytic cell line. To define the doses used in the interaction experiments between IR-A+UVB, dose/response curves were made after exposure to IR-A or UVB. The IR-A dose chosen was 0.8J/cm(2) because this dose caused no significant inhibition of proliferation effects and viability decreased. For UVB exposure, a dose of 0.015J/cm(2), which showed a decrease in viable cell number by approximately 50% in relation to control until 72h, was selected. For IR-A+UVB, cell proliferation recovery was showed, decreasing DNA damage and lipid peroxide content when compared to UVB alone. Besides, the results obtained for ROS and antioxidant capacity showed that the protection observed was probably not related to decreased oxidative stress. In conclusion, non-thermal IR-A was capable of protecting the melan-a cells from UVB induced damage.

  4. Epidermal UV-A absorbance and whole-leaf flavonoid composition in pea respond more to solar blue light than to solar UV radiation.

    PubMed

    Siipola, Sari M; Kotilainen, Titta; Sipari, Nina; Morales, Luis O; Lindfors, Anders V; Robson, T Matthew; Aphalo, Pedro J

    2015-05-01

    Plants synthesize phenolic compounds in response to certain environmental signals or stresses. One large group of phenolics, flavonoids, is considered particularly responsive to ultraviolet (UV) radiation. However, here we demonstrate that solar blue light stimulates flavonoid biosynthesis in the absence of UV-A and UV-B radiation. We grew pea plants (Pisum sativum cv. Meteor) outdoors, in Finland during the summer, under five types of filters differing in their spectral transmittance. These filters were used to (1) attenuate UV-B; (2) attenuate UV-B and UV-A < 370 nm; (3) attenuate UV-B and UV-A; (4) attenuate UV-B, UV-A and blue light; and (5) as a control not attenuating these wavebands. Attenuation of blue light significantly reduced the flavonoid content in leaf adaxial epidermis and reduced the whole-leaf concentrations of quercetin derivatives relative to kaempferol derivatives. In contrast, UV-B responses were not significant. These results show that pea plants regulate epidermal UV-A absorbance and accumulation of individual flavonoids by perceiving complex radiation signals that extend into the visible region of the solar spectrum. Furthermore, solar blue light instead of solar UV-B radiation can be the main regulator of phenolic compound accumulation in plants that germinate and develop outdoors.

  5. Epidermal UV-A absorbance and whole-leaf flavonoid composition in pea respond more to solar blue light than to solar UV radiation.

    PubMed

    Siipola, Sari M; Kotilainen, Titta; Sipari, Nina; Morales, Luis O; Lindfors, Anders V; Robson, T Matthew; Aphalo, Pedro J

    2015-05-01

    Plants synthesize phenolic compounds in response to certain environmental signals or stresses. One large group of phenolics, flavonoids, is considered particularly responsive to ultraviolet (UV) radiation. However, here we demonstrate that solar blue light stimulates flavonoid biosynthesis in the absence of UV-A and UV-B radiation. We grew pea plants (Pisum sativum cv. Meteor) outdoors, in Finland during the summer, under five types of filters differing in their spectral transmittance. These filters were used to (1) attenuate UV-B; (2) attenuate UV-B and UV-A < 370 nm; (3) attenuate UV-B and UV-A; (4) attenuate UV-B, UV-A and blue light; and (5) as a control not attenuating these wavebands. Attenuation of blue light significantly reduced the flavonoid content in leaf adaxial epidermis and reduced the whole-leaf concentrations of quercetin derivatives relative to kaempferol derivatives. In contrast, UV-B responses were not significant. These results show that pea plants regulate epidermal UV-A absorbance and accumulation of individual flavonoids by perceiving complex radiation signals that extend into the visible region of the solar spectrum. Furthermore, solar blue light instead of solar UV-B radiation can be the main regulator of phenolic compound accumulation in plants that germinate and develop outdoors. PMID:25040832

  6. High-Dose 131I-Tositumomab (Anti-CD20) Radioimmunotherapy for Non-Hodgkin's Lymphoma: Adjusting Radiation Absorbed Dose to Actual Organ Volumes

    SciTech Connect

    Rajendran, Joseph G.; Fisher, Darrell R.; Gopal, A K.; Durack, L. D.; Press, O. W.; Eary, Janet F.

    2004-06-01

    Radioimmunotherapy (RIT) using 131I-tositumomab has been used successfully to treat relapsed or refractory B-cell non-Hodgin's lymphoma (NHL). Our approach to treatment planning has been to determine limits on radiation absorbed close to critical nonhematopoietic organs. This study demonstrates the feasibility of using CT to adjust for actual organ volumes in calculating organ-specific absorbed dose estimates. Methods: Records of 84 patients who underwent biodistribution studies after a trace-labeled infusion of 131I-tositumomab for RIT (January 1990 and April 2003) were reviewed. Serial planar -camera images and whole-body Nal probe counts were obtained to estimate 131I-antibody source-organ residence times as recommended by the MIRD Committee. The source-organ residence times for standard man or woman were adjusted by the ratio of the MIRD phantom organ mass to the CT-derived organ mass. Results: The mean radiation absorbed doses (in mGy/MBq) for our data using the MIRD model were lungs= 1.67; liver= 1.03; kidneys= 1.08; spleen= 2.67; and whole body= 0.3; and for CT volume-adjusted organ volumes (in mGy/MBq) were lungs= 1.30; liver= 0.92; kidneys= 0.76; spleen= 1.40; and whole body= 0.22. We determined the following correlation coefficients between the 2 methods for the various organs; lungs, 0.49; (P= 0.0001); liver, 0.64 (P= 0.004); kidneys, 0.45 (P= 0.0001), for the residence times. For therapy, patients received mean 131I administered activities of 19.2 GBq (520 mCi) after adjustment for CT-derived organ mass compared with 16.0 GBq (433 mCi) that would otherwise have been given had therapy been based only using standard MIRD organ volumes--a statistically significant difference (P= 0.0001). Conclusion: We observed large variations in organ masses among our patients. Our treatments were planned to deliver the maximally tolerated radiation dose to the dose-limiting normal organ. This work provides a simplified method for calculating patient-specific radiation

  7. Simulations of Radiation Heat Transfer in Design of Alternative Infrared Emitters

    NASA Astrophysics Data System (ADS)

    Loufek, J.

    The article presents a numerical model of radiation heat transfer. The model is designed to bring a support for innovation in heating shell moulds. Such shell moulds are used in the process of creating leather imitation by slush moulding method. The model description aims at the relevant radiation heat transfer processes. The contribution also provides comparison between model results and relevant measured values to outline that described model corresponds with real behaviour. One of the aims of the work is the use of the eventual simulation tool for a design such a shape of reflector that will be suitable for required criteria. According to that, the article describes the heat distribution and characteristics of considered infrared emitters. This implemented tool, along with the optimization algorithms, can be used to find out the best position or shape of emitters. After the particular model design, during the process of its calibration, the simulated values are needed to be compared with the real measured values. The article briefly demonstrates the mentioned procedure as a utility for practical usage.

  8. Wavelength-dependent penetration depth of near infrared radiation into cartilage.

    PubMed

    Padalkar, M V; Pleshko, N

    2015-04-01

    Articular cartilage is a hyaline cartilage that lines the subchondral bone in the diarthrodial joints. Near infrared (NIR) spectroscopy is emerging as a nondestructive modality for the evaluation of cartilage pathology; however, studies regarding the depth of penetration of NIR radiation into cartilage are lacking. The average thickness of human cartilage is about 1-3 mm, and it becomes even thinner as OA progresses. To ensure that spectral data collected is restricted to the tissue of interest, i.e. cartilage in this case, and not from the underlying subchondral bone, it is necessary to determine the depth of penetration of NIR radiation in different wavelength (frequency) regions. In the current study, we establish how the depth of penetration varies throughout the NIR frequency range (4000-10 000 cm(-1)). NIR spectra were collected from cartilage samples of different thicknesses (0.5 mm to 5 mm) with and without polystyrene placed underneath. A separate NIR spectrum of polystyrene was collected as a reference. It was found that the depth of penetration varied from ∼1 mm to 2 mm in the 4000-5100 cm(-1) range, ∼3 mm in the 5100-7000 cm(-1) range, and ∼5 mm in the 7000-9000 cm(-1) frequency range. These findings suggest that the best NIR region to evaluate cartilage with no subchondral bone contribution is in the range of 4000-7000 cm(-1).

  9. Infrared transmission through cirrus clouds: a radiative model for target detection.

    PubMed

    Liou, K N; Takano, Y; Ou, S C; Heymsfield, A; Kreiss, W

    1990-05-01

    An IR transmission model for thin and subvisual cirrus clouds composed of hexagonal ice crystals with a specific use for target detection has been developed. The present model includes parameterizations of the ice crystal size distribution and the position of cirrus clouds in terms of ambient temperature. To facilitate the scattering and absorption calculations for hexagonal column and plate crystals in connection with transmission calculations, we have developed parameterized equations for their single scattering properties by using the results computed from a geometric ray-tracing program. The successive order-of-scattering approach has been used to account for multiple scattering of ice crystals associated with a target-detector system. The direct radiance, path radiance, and radiances produced by multiple scattering and background radiation involving cirrus clouds have been computed for 3.7- and 10-,microm wavelengths. We show that the background radiance at the 3.7-,microm wavelength is relatively small so that a high contrast may be obtained using this wavelength for the detection of airborne and ground-based objects in the presence of thin cirrus clouds. Finally, using the present model, including a simple prediction scheme for the ice crystal size distribution and cloud position, the transmission of infrared radiation through cirrus clouds can be efficiently evaluated if the target-detector geometry is defined.

  10. An appraisal of the need for infrared radiation protection in sunscreens.

    PubMed

    Diffey, Brian; Cadars, Benoît

    2016-03-01

    Many sunscreens incorporate agents that are said to protect against infrared (IR) damage in the skin but we lack any real data on their benefit in the context of normal human behaviour in the sun. The object of this study was to examine typical IR exposure levels to the sun and industrial sources in order to decide whether there is a need for sunscreens to contain agents that protect against IR radiation, specifically the IR-A waveband. We reviewed claims currently made by products offering protection against IR-A and studies on the biological and clinical effects attributed to IR-A, and compared IR-A exposure levels from these studies with those typically received from the sun and from industrial sources. We found that annual levels of IR-A exposure resulting from typical behaviour in the sun are commensurate with those experienced occupationally by workers exposed to industrial sources of IR, such as steel and glass furnaces. Yet these workers appear to suffer little in the way of chronic skin damage. We conclude that there is not compelling evidence to demonstrate that observable, deleterious cutaneous effects are occurring at doses of solar IR radiation corresponding to those experienced by populations in their normal environments and for this reason we believe it is premature to incorporate IR protection into topical sunscreens and to make claims related to ageing of the skin that consumers may expect to see. PMID:26846677

  11. Cosmic ray modulation of infra-red radiation in the atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, K. L.; Lockwood, M.

    2013-03-01

    Cosmic rays produce molecular cluster ions as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by charged clusters has not hitherto been observed. In an atmospheric experiment, a narrowband thermopile filter radiometer centred on 9.15 μm, an absorption band previously associated with infra-red absorption of molecular cluster ions, was used to monitor changes following events identified by a cosmic ray telescope sensitive to high-energy (>400 MeV) particles, principally muons. The average change in longwave radiation in this absorption band due to molecular cluster ions is 7 mWm-2. The integrated atmospheric energy density for each event is 2 Jm-2, representing an amplification factor of 1012 compared to the estimated energy density of a typical air shower. This absorption is expected to occur continuously and globally, but calculations suggest that it has only a small effect on climate.

  12. Radiative transfer model for aerosols at infrared wavelengths for passive remote sensing applications: revisited.

    PubMed

    Ben-David, Avishai; Davidson, Charles E; Embury, Janon F

    2008-11-01

    We introduced a two-dimensional radiative transfer model for aerosols in the thermal infrared [Appl. Opt.45, 6860-6875 (2006)APOPAI0003-693510.1364/AO.45.006860]. In that paper we superimposed two orthogonal plane-parallel layers to compute the radiance due to a two-dimensional (2D) rectangular aerosol cloud. In this paper we revisit the model and correct an error in the interaction of the two layers. We derive new expressions relating to the signal content of the radiance from an aerosol cloud based on the concept of five directional thermal contrasts: four for the 2D diffuse radiance and one for direct radiance along the line of sight. The new expressions give additional insight on the radiative transfer processes within the cloud. Simulations for Bacillus subtilis var. niger (BG) bioaerosol and dustlike kaolin aerosol clouds are compared and contrasted for two geometries: an airborne sensor looking down and a ground-based sensor looking up. Simulation results suggest that aerosol cloud detection from an airborne platform may be more challenging than for a ground-based sensor and that the detection of an aerosol cloud in emission mode (negative direct thermal contrast) is not the same as the detection of an aerosol cloud in absorption mode (positive direct thermal contrast).

  13. Wavelength-Dependent Penetration Depth of Near Infrared Radiation into Cartilage

    PubMed Central

    Padalkar, M.V.; Pleshko, N.

    2015-01-01

    Articular cartilage is a hyaline cartilage that lines the subchondral bone in a diarthrodial joint. Near infrared (NIR) spectroscopy has been emerging as a nondestructive modality for evaluation of cartilage pathology. However, studies of the depth of penetration of NIR radiation into cartilage are lacking. The average thickness of human cartilage is about 1-3 mm, and it becomes even thinner as OA progresses. To ensure that the spectral data collected is restricted to the tissue of interest i.e. cartilage in this case, and not from the underlying subchondral bone, it is necessary to determine the depth of penetration of NIR radiation in different wavelength (frequency) regions. In the current study we establish how the depth of penetration varies throughout the NIR frequency range (4000-10000 cm-1). NIR spectra were collected from cartilage samples of different thicknesses (0.5 mm to 5 mm) with and without polystyrene placed underneath. A separate NIR spectrum of polystyrene was collected as a reference. It was found that the depth of penetration varied from ∼1 mm to 2 mm in the 4000-5100 cm-1 range, to ∼3 mm in the 5100-7000 cm-1 range, and to ∼5 mm in the 7000-9000 cm-1 frequency range. These findings suggest that the best NIR region to evaluate cartilage only with no subchondral bone contribution is between 4000-7000 cm-1. PMID:25630381

  14. Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings

    NASA Technical Reports Server (NTRS)

    Johnson, C. F.; Brown, C. S.; Wheeler, R. M.; Sager, J. C.; Chapman, D. K.; Deitzer, G. F.

    1996-01-01

    Oat (Avena sativa cv Seger) seedlings were irradiated with IR light-emitting diode (LED) radiation passed through a visible-light-blocking filter. Infrared LED irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. Thus, the oat seedlings in this study were able to detect IR LED radiation. These findings call into question the use of IR LED as a safe-light for some photosensitive plant response experiments. These findings also expand the defined range of wavelengths involved in radiation-gravity (light-gravity) interactions to include wavelengths in the IR region of the spectrum.

  15. Local changes in arterial oxygen saturation induced by visible and near-infrared light radiation.

    PubMed

    Yesman, S S; Mamilov, S O; Veligotsky, D V; Gisbrecht, A I

    2016-01-01

    In this study, we investigate the efficiency of laser radiation on oxyhemoglobin (HbO2) rate in blood vessels and its wavelength dependence. The results of in vivo experimental measurements of the laser-induced photodissociation of HbO2 in cutaneous blood vessels in the visible and near-infrared (IR) spectral range are presented. Arterial oxygen saturation (SpO2) was measured by a method of fingertip pulse oximetry, which is based on the measurement of the modulated pulse wave of the blood. The light irradiating the finger was provided by corresponding light-emitting diodes (LED) at 15 wavelengths in the 400-940 nm spectrum range. Statistical results with a value of p < 0.05 were viewed as being significant for all volunteers. The results show that there is a decrease in SpO2 in the blood under the influence of the transcutaneous laser irradiation. Three maxima in the spectral range (530, 600, and 850 nm) are revealed, wherein decrease in the relative concentration of SpO2 reaches 5 % ± 0.5 %. Near-IR radiation plays a dominant role in absorption of laser radiation by oxyhemoglobin in deeper layers of tissue blood vessels. The obtained data correlate with the processes of light propagation in biological tissue. The observed reduction in SpO2 indicates the process of photodissociation of HbO2 in vivo and may result in local increase in O2 in the tissue. Such laser-induced enrichment of tissue oxygenation can be used in phototherapy of pathologies, where the elimination of local tissue hypoxia is critical. PMID:26637304

  16. Local changes in arterial oxygen saturation induced by visible and near-infrared light radiation.

    PubMed

    Yesman, S S; Mamilov, S O; Veligotsky, D V; Gisbrecht, A I

    2016-01-01

    In this study, we investigate the efficiency of laser radiation on oxyhemoglobin (HbO2) rate in blood vessels and its wavelength dependence. The results of in vivo experimental measurements of the laser-induced photodissociation of HbO2 in cutaneous blood vessels in the visible and near-infrared (IR) spectral range are presented. Arterial oxygen saturation (SpO2) was measured by a method of fingertip pulse oximetry, which is based on the measurement of the modulated pulse wave of the blood. The light irradiating the finger was provided by corresponding light-emitting diodes (LED) at 15 wavelengths in the 400-940 nm spectrum range. Statistical results with a value of p < 0.05 were viewed as being significant for all volunteers. The results show that there is a decrease in SpO2 in the blood under the influence of the transcutaneous laser irradiation. Three maxima in the spectral range (530, 600, and 850 nm) are revealed, wherein decrease in the relative concentration of SpO2 reaches 5 % ± 0.5 %. Near-IR radiation plays a dominant role in absorption of laser radiation by oxyhemoglobin in deeper layers of tissue blood vessels. The obtained data correlate with the processes of light propagation in biological tissue. The observed reduction in SpO2 indicates the process of photodissociation of HbO2 in vivo and may result in local increase in O2 in the tissue. Such laser-induced enrichment of tissue oxygenation can be used in phototherapy of pathologies, where the elimination of local tissue hypoxia is critical.

  17. Internal absorber solar collector

    DOEpatents

    Sletten, Carlyle J.; Herskovitz, Sheldon B.; Holt, F. S.; Sletten, E. J.

    1981-01-01

    Thin solar collecting panels are described made from arrays of small rod collectors consisting of a refracting dielectric rod lens with an absorber imbedded within it and a reflecting mirror coated on the back side of the dielectric rod. Non-tracking collector panels on vertical walls or roof tops receive approximately 90% of solar radiation within an acceptance zone 60.degree. in elevation angle by 120.degree. or more in the azimuth sectors with a collector concentration ratio of approximately 3.0. Miniaturized construction of the circular dielectric rods with internal absorbers reduces the weight per area of glass, plastic and metal used in the collector panels. No external parts or insulation are needed as heat losses are low due to partial vacuum or low conductivity gas surrounding heated portions of the collector. The miniature internal absorbers are generally made of solid copper with black selective surface and the collected solar heat is extracted at the collector ends by thermal conductivity along the absorber rods. Heat is removed from end fittings by use of liquid circulants. Several alternate constructions are provided for simplifying collector panel fabrication and for preventing the thermal expansion and contraction of the heated absorber or circulant tubes from damaging vacuum seals. In a modified version of the internal absorber collector, oil with temperature dependent viscosity is pumped through a segmented absorber which is now composed of closely spaced insulated metal tubes. In this way the circulant is automatically diverted through heated portions of the absorber giving higher collector concentration ratios than theoretically possible for an unsegmented absorber.

  18. The combination of infrared and microwave radiation to quantify trace elements in organic samples by ICP OES.

    PubMed

    Dantas, A N S; Matos, W O; Gouveia, S T; Lopes, G S

    2013-03-30

    Sample-decomposition methods using microwave radiation in closed systems have been commonly used in the analysis of inorganic constituents; however, these methods are limited to small amounts of organic samples. This work proposes the combined use of infrared radiation and microwave radiation (IR-MW) to increase the amount of organic samples digested. The determination of Al, Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn in human-feed samples was accomplished by ICP OES. The results were in agreement with those obtained from conventional decomposition by microwave radiation (closed system). The results obtained using the proposed IR-MW system for standard reference material (whole milk powder, NIST 8435) were also compared. Agreements of 85-100% were obtained for Al, Ca, Cu, Fe, K, Mg, Na, P and Zn in the standard reference material. The IR-MW system is simple to implement and cheap because it uses commercially available infrared lamps and allows the use of infrared radiation in the microwave-digestion vessel. Additionally, it is possible to reach better precision in the analysis of the human-feed samples using the IR-MW system. The proposed method also allows total digestion of large sample amounts or samples rich in organic compounds can also be performed in the IR-MW system using small volumes of nitric acid.

  19. Investigation on the effect of MR elastomer based adaptive vibration absorbers on the radiated sound from circular elastic plates

    NASA Astrophysics Data System (ADS)

    Hemmatian, M.; Sedaghati, R.

    2016-04-01

    This study aims to investigate the effect of using magnetorheological elastomer (MRE)-based adaptive tuned vibration absorbers (ATVA) on the sound transmission in an elastic plate. Sound transmission loss (STL) of an elastic circular thin plate is analytically studied. The plate is excited by a plane acoustic wave as an incident sound and the displacement of the plate is calculated using corresponding mode shapes of the system for clamped boundary condition. Rayleigh integral approach is used to express the transmitted sound pressure in terms of the plate's displacement modal amplitude. In order to increase sound transmission loss of the plate, the MRE-based ATVA is considered. The basic idea is to be able to change the stiffness of the ATVA by varying magnetic field in order to reduce the transmitted acoustic energy of the host structure in a wide frequency range. Here, a MRE-based ATVA under the shear mode consisting of an oscillator mass, magnetic conductor, coils and MRE is investigated. In order to predict the viscoelastic characteristics of the field-dependent MRE based on the applied magnetic field, the double pole model is used. Finally, MRE-based ATVAs are integrated with the plate to absorb the plate energy with the aim of decreasing the transmitted sound power. Results show that plate with integrated MRE-based ATVAs suppresses the axisymmetric vibration of the plate and thus considerably improves the STL. Parametric studies on the influence of the position of MRE-based ATVAs and the effects of applied current on their performance are also presented.

  20. Nanowire-based frequency-selective capacitive photodetector for resonant detection of infrared radiation at room temperature

    SciTech Connect

    Bandyopadhyay, Saumil

    2014-07-14

    Characteristics of a capacitive infrared photodetector that works at room temperature by registering a change in capacitance upon illumination are reported. If used in an ideal resonant inductor-resistor-capacitor circuit, it can exhibit zero dark current, zero standby power dissipation, infinite detectivity, and infinite light-to-dark contrast ratio. It is also made frequency-selective by employing semiconductor nanowires that selectively absorb photons of energies close to the nanowire's bandgap. Based on measured parameters, the normalized detectivity is estimated to be ∼3 × 10{sup 7} Jones for 1.6 μm IR wavelength at room temperature.