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Sample records for root surface radiated

  1. Lunar Surface Radiation Display

    NASA Astrophysics Data System (ADS)

    Burke, James; Albalat, Andrea Jaime; Tlustos, Reinhard

    2014-05-01

    Effects of the lunar surface environment can be observed with a simple passive experiment consisting of small material samples placed in view of a lander or rover camera. This paper will describe, advocate and demonstrate the creation, ideally by students or young professionals, of a small standard sample holder, for example a string of different glass beads in front of a white or detector background, that can be replicated and installed on any of the coming series of lunar surface spacecraft. Effects of solar and cosmic ionizing radiation and local temperature, such as darkening and annealing, will be readily apparent in different kinds of glass, plastic and crystalline beads. Costs of preparation and installation, and impact on the main mission, can be kept to a level essentially negligible in proportion to project budgets.

  2. Solar radiation on inclined surfaces

    NASA Astrophysics Data System (ADS)

    1980-05-01

    Mean monthly values of daily shortwave radiation on inclined surfaces are presented for 13 locations in India. Values of direct, diffuse sky, reflected, and total shortwave radiation incident on an inclined surface are given for 9 slope angles (measured from the horizontal) and 8 aspects. All the data are computed using measured values of the total shortwave radiation on a horizontal surface according to the techniques described. Maximum and minimum values of direct solar radiation during each month are underlined and marked by asterisk respectively. Actual and potential users of radiation data, particularly those in the fields of agriculture, horticulture, forestry, architecture, heating and ventilating engineering, and photovoltaic systems, it is hoped, would find this publication useful in planning and designing of solar radiation devices.

  3. Surface Power Radiative Cooling Tests

    NASA Astrophysics Data System (ADS)

    Vaughn, Jason; Schneider, Todd

    2006-01-01

    Terrestrial nuclear power plants typically maintain their temperature through convective cooling, such as water and forced air. However, the space environment is a vacuum environment, typically 10-8 Torr pressure, therefore in proposed missions to the lunar surface, power plants would have to rely on radiative cooling to remove waste heat. Also, the Martian surface has a very tenuous atmosphere (e.g. ~5 Torr CO2), therefore, the main heat transfer method on the Martian surface is also radiative. Because of the lack of atmosphere on the Moon and the tenuous atmosphere on Mars, surface power systems on both the Lunar and Martian surface must rely heavily on radiative heat transfer. Because of the large temperature swings on both the lunar and the Martian surfaces, trying to radiate heat is inefficient. In order to increase power system efficiency, an effort is underway to test various combinations of materials with high emissivities to demonstrate their ability to survive these degrading atmospheres to maintain a constant radiator temperature improving surface power plant efficiency. An important part of this effort is the development of a unique capability that would allow the determination of a materials emissivity at high temperatures. A description of the test capability as well as initial data is presented.

  4. Surface Power Radiative Cooling Tests

    SciTech Connect

    Vaughn, Jason; Schneider, Todd

    2006-01-20

    Terrestrial nuclear power plants typically maintain their temperature through convective cooling, such as water and forced air. However, the space environment is a vacuum environment, typically 10-8 Torr pressure, therefore in proposed missions to the lunar surface, power plants would have to rely on radiative cooling to remove waste heat. Also, the Martian surface has a very tenuous atmosphere (e.g. {approx}5 Torr CO2), therefore, the main heat transfer method on the Martian surface is also radiative. Because of the lack of atmosphere on the Moon and the tenuous atmosphere on Mars, surface power systems on both the Lunar and Martian surface must rely heavily on radiative heat transfer. Because of the large temperature swings on both the lunar and the Martian surfaces, trying to radiate heat is inefficient. In order to increase power system efficiency, an effort is underway to test various combinations of materials with high emissivities to demonstrate their ability to survive these degrading atmospheres to maintain a constant radiator temperature improving surface power plant efficiency. An important part of this effort is the development of a unique capability that would allow the determination of a materials emissivity at high temperatures. A description of the test capability as well as initial data is presented.

  5. Surface modification of tooth root canal after application of an X-ray opaque waveguide

    NASA Astrophysics Data System (ADS)

    Dostálová, T.; Jelínková, H.; Šulc, J.; Němec, M.; Koranda, P.; Bartoňová, M.; Radina, P.; Miyagi, M.; Shi, Y.-W.; Matsuura, Y.

    The interest in endodontic use of dental laser systems has been increasing. With the development of thin and flexible delivery systems for various wavelengths, laser applications in endodontics may become even more desirable. The aim of this study is to check the X-ray opacity of a hollow waveguide and to observe the results after laser root canal treatment. The root canal systems of 10 molars were treated endodontically by laser. For the laser radiation source, an Er:YAG laser system generating a wavelength of 2940 nm and an Alexandrite laser system generating a wavelength of 375 nm were used. The hollow waveguide used was checked under X-ray . A root canal surface treated by laser radiation was analyzed by a scanning electron microscope (SEM). The special hollow glass waveguide used was visible in the root canal system under X-ray imaging. Surface modification of the root canal after laser treatment was not found. After conventional treatment the root canal was enlarged. The surface was covered with a smear layer. After application of both laser systems, the smear layer was removed. The resulting canal surface was found to be clean and smooth. Under SEM observation open dentinal tubules were visible. No cracks were present, nor were surface modifications observed.

  6. Root canal surface after application of an x-ray opaque waveguide

    NASA Astrophysics Data System (ADS)

    Dostalova, Tatjana; Jelinkova, Helena; Bartonova, Marie; Sulc, Jan; Nemec, Michal; Koranda, Petr; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji

    2004-05-01

    The success of endodontic treatment depends on the methods used for shaping, cleaning, disinfecting, and sealing of a root canal. In the last few decades, big progress has been achieved in the application of the following methods: manual instrumentation, sonic and ultrasonic devices, and rotary instruments. The procedures used in the root canal system preparation result in a smear layer creation. The aim of this study was to give more precision to the smear layer removal using laser radiation. The root canal systems of 20 human teeth were treated endodontically. As laser radiation sources, Er:YAG laser system generating a wavelength of 2940 nm (rep. rate 1.5 Hz, spot size diameter 320 um, number of pulses 55, energy 100 mJ) and Alexandrite laser system generating a wavelength of 375 nm (rep. rate 1 Hz, spot size diameter 320 um, number of pulses 200, energy 1 mJ) were used. As a delivery system, a hollow glass waveguide with the special X-ray contrast cover was used. The flexible waveguide was moved via root canal and the laser radiation cleaned the wall surface. After application of Er:YAG laser radiation, the smear layer was fully removed, the surface was clean and smooth, and in the SEM investigation the open dentinal tubules were visible. No cracks were determined. The surface modifications were also not observed after endodontic preparation as well as Alexandrite laser radiation therapy. The whole treatment can be checked by X-ray machine.

  7. Characterization of Root Surface and Endorhizosphere Pseudomonads in Relation to Their Colonization of Roots

    PubMed Central

    van Peer, Ron; Punte, Helma L. M.; de Weger, Letty A.; Schippers, Bob

    1990-01-01

    An extensive colonization of the endorhizosphere by fluorescent pseudomonads was observed in tomato plants grown on artificial substrates. These studies reveal that a significantly higher percentage of pseudomonads obtained from the endorhizosphere (30%) reduced plant growth than those obtained from the root surface (4%). Lipopolysaccharide patterns, cell envelope protein patterns, and other biochemical characteristics indicated that Pseudomonas isolates obtained from the endorhizosphere are distinct from Pseudomonas isolates obtained from the root surface. Isolates from the endorhizosphere especially were able to recolonize the endorhizosphere of both sterile and nonsterile tomato roots. The ability of the endorhizosphere isolates to colonize the endorhizosphere significantly correlated with their agglutination by tomato root agglutinin but did not correlate with chemotaxis to seed exudates of tomato. No correlation between colonization of the endorhizosphere and agglutination by root agglutinin could be demonstrated for the root surface isolates. We propose that agglutination of specific Pseudomonas strains by root agglutinin is of importance in the initial phase of adherence of bacteria to the root surface. Images PMID:16348258

  8. Surface wave chemical detector using optical radiation

    DOEpatents

    Thundat, Thomas G.; Warmack, Robert J.

    2007-07-17

    A surface wave chemical detector comprising at least one surface wave substrate, each of said substrates having a surface wave and at least one measurable surface wave parameter; means for exposing said surface wave substrate to an unknown sample of at least one chemical to be analyzed, said substrate adsorbing said at least one chemical to be sensed if present in said sample; a source of radiation for radiating said surface wave substrate with different wavelengths of said radiation, said surface wave parameter being changed by said adsorbing; and means for recording signals representative of said surface wave parameter of each of said surface wave substrates responsive to said radiation of said different wavelengths, measurable changes of said parameter due to adsorbing said chemical defining a unique signature of a detected chemical.

  9. [XPS analysis of tea plant leaf and root surface].

    PubMed

    Fang, Jiang-yu; Wan, Xiao-chun

    2008-09-01

    XPS was applied to analyze the surface chemical composition and structure of the tea plant leaf and root. It was detected that the surface is made up of mainly 4 elements: C, O, N and Al, with little P and F in abaxial leaf. Based on the botanic epidermis structure and the chemical composition, with the help of the standard spectrum data bank on line and the wood XPS study results, and through line Gaussian and Lorentizian the mixed, the binding energy of C(1s) of the leaf surface was classified as 3 types: the first was C1, with the electron binding energy of 285 eV, from C-C or C-H group, representing lipid compound like cutin and wax. C2 with the binding energy of 286.35 eV in the adaxial and 286.61 eV in the abaxial, came from the single bond of carbon and oxygen C-O, mainly standing for cellulose. C3 with the binding energy of approximately 288 eV (288.04 eV in adaxial and 288.09 eV in abaxial) was the sign of C=O group, which is acyl in protein with the confirmation of N(1s) (399-401 eV)and O(1s) analyses. In the root surface, besides the same compounds of cutin and wax (C1, binding energy 285 eV), cellulose (C2, binding energy 286.49 eV) and protein (C3, binding energy 288.78 eV)as in the leaf, there appeared C5 type with the binding energy of 283.32 eV. Because it was lower than C1, it was estimated as carbon linking to metal. Both the leaf and the root surfaces didn't have C4, a type of O-C=O, which is common in wood surface with the highest oxidated carbon of 289-289.5 eV binding energy, indicating that organic acid secreted by the root existed freely on the root surface, without any chemical association with the surface compounds. The results of the separated spectrum of O(1s) supported the above C(1s) results. By the ratio of each type of C, there were more oxygen groups in the abaxial than in the adaxial, implicating more active chemical properties on the abaxial. Compared with the leaf, cutin and wax was little in the root and oxygen groups were many

  10. Reflective overcoats for radiation control surfaces

    NASA Technical Reports Server (NTRS)

    White, Susan M.

    1991-01-01

    Theoretical models are developed to predict the surface properties of a coating layer composed of particles of a known size distribution, applied to an opaque substrate, such as a metal or reaction cured glass (RCG). The surface temperature attained at radiative equilibrium by an overcoated surface subject to a given heat flux is calculated. The incident radiation was assumed to exhibit the spectral distribution characteristic of a black body at different temperatures or equivalently, having different peak wavelengths, with the energy level scaled to give a range of desired surface radiative heat fluxes. This approach allows a straightforward comparison of the thernal response of a surface to incident radiation having the energy predominantly in a characteristic wavelength band and a well-defined spectral distribution. The ratio of the radiative heat flux to the total heat flux was varied, and the different geometric and material parameters of such overcoat layers were explored. The model was applied to representative surface heating rates to the Aeroasssisted Flight Experiment (AFE) and to Aeroassisted Space Transfer Vehicles (ASTVs). The predicted radiative energy flux to the surface of the AFE vehicle gives a single-point comparison of the surface temperatures attained with and without a selective-reflector overcoat on the vehicle surface. The specific objective of this work is to identify the most desirable radiative properties of an overcoat/substrate system for this environment.

  11. Surface radiation budget for climate applications

    NASA Technical Reports Server (NTRS)

    Suttles, J. T. (Editor); Ohring, G. (Editor)

    1986-01-01

    The Surface Radiation Budget (SRB) consists of the upwelling and downwelling radiation fluxes at the surface, separately determined for the broadband shortwave (SW) (0 to 5 micron) and longwave (LW) (greater than 5 microns) spectral regions plus certain key parameters that control these fluxes, specifically, SW albedo, LW emissivity, and surface temperature. The uses and requirements for SRB data, critical assessment of current capabilities for producing these data, and directions for future research are presented.

  12. Decadal Variations in Surface Solar Radiation

    NASA Astrophysics Data System (ADS)

    Wild, M.

    2007-05-01

    Satellite estimates provide some information on the amount of solar radiation absorbed by the planet back to the 1980s. The amount of solar radiation reaching the Earth surface can be traced further back in time, untill the 1960s at widespread locations and into the first half of the 20th Century at selected sites. These surface sites suggest significant decadal variations in solar radiation incident at the surface, with indication for a widespread dimming from the 1960s up to the mid 1980s, and a recovery thereafter. Indications for changes in surface solar radiation may also be seen in observatinal records of diurnal temperature range, which provide a better global coverage than the radiation measurrements. Trends in diurnal temperature ranges over global land surfaces show, after decades of decline, a distinct tendency to level off since the mid 1980s. This provides further support for a significant shift in surface solar radiation during the 1980s. There is evidence that the changes in surface solar radiation are linked to associated changes in atmospheric aerosol. Variations in scattering sulfur and absorbing black carbon aerosols are in line with the variations in surface solar radiation. This suggests that at least a part of the variations in surface solar radiation should also be seen in the clear sky planetary albedo. Model simulations with a GCM which includes a sophisticated interactive treatment of aerosols and their emission histories (ECHAM5 HAM), can be used to address this issue. The model is shown to be capable of reproducing the reversal from dimming to brightening under cloud-free conditions in many parts of the world, in line with observational evidence. Associated changes can also be seen in the clear sky planetary albedo, albeit of smaller magnitude.

  13. Effect of diode laser radiation in root canal wall dentine: a microbiological study

    NASA Astrophysics Data System (ADS)

    Gutknecht, Norbert; Conrads, Georg; Apel, Christian; Schubert, Claus; Lampert, Friedrich

    2000-03-01

    The aim of this study was to investigate the antibacterial effect of a diode laser in deep root canal dentine. The microbial colonization of root canal dentine can lead to failures in conventional endodontic treatment if only an inadequate bacterial reduction is achieved through canal treatment and chemical disinfection. 100 micrometer, 300 micrometer and 500 micrometer bovine dentine slices obtained by longitudinal sections were sterilized and inoculated on one side with an Enterococcus faecalis suspension. Laser radiation was performed on the opposite side with the diode laser, emits light at 810 nm and operates in the continuous wave mode (cw). Radiation was performed using a 400 micrometer tapered fiber tip at an angle of approx. 5 degrees to the surface over a period of 30 s. The output power at the distal end of the tip was 0.6 watt. The bacteria were then eluted through vibration and cultured on blood agar plates. The colony count reflected the antibacterial effect of laser radiation as a function of the layer thickness. A mean bacterial reduction of 74% was achieved even with a 500 micrometer thick slice. This investigation indicates that the diode laser can support the bacterial reduction in endodontic treatment.

  14. Development of a space radiation Monte Carlo computer simulation based on the FLUKA and ROOT codes.

    PubMed

    Pinsky, L S; Wilson, T L; Ferrari, A; Sala, P; Carminati, F; Brun, R

    2001-01-01

    This NASA funded project is proceeding to develop a Monte Carlo-based computer simulation of the radiation environment in space. With actual funding only initially in place at the end of May 2000, the study is still in the early stage of development. The general tasks have been identified and personnel have been selected. The code to be assembled will be based upon two major existing software packages. The radiation transport simulation will be accomplished by updating the FLUKA Monte Carlo program, and the user interface will employ the ROOT software being developed at CERN. The end-product will be a Monte Carlo-based code which will complement the existing analytic codes such as BRYNTRN/HZETRN presently used by NASA to evaluate the effects of radiation shielding in space. The planned code will possess the ability to evaluate the radiation environment for spacecraft and habitats in Earth orbit, in interplanetary space, on the lunar surface, or on a planetary surface such as Mars. Furthermore, it will be useful in the design and analysis of experiments such as ACCESS (Advanced Cosmic-ray Composition Experiment for Space Station), which is an Office of Space Science payload currently under evaluation for deployment on the International Space Station (ISS). FLUKA will be significantly improved and tailored for use in simulating space radiation in four ways. First, the additional physics not presently within the code that is necessary to simulate the problems of interest, namely the heavy ion inelastic processes, will be incorporated. Second, the internal geometry package will be replaced with one that will substantially increase the calculation speed as well as simplify the data input task. Third, default incident flux packages that include all of the different space radiation sources of interest will be included. Finally, the user interface and internal data structure will be melded together with ROOT, the object-oriented data analysis infrastructure system. Beyond

  15. Development of a space radiation Monte Carlo computer simulation based on the FLUKA and ROOT codes.

    PubMed

    Pinsky, L S; Wilson, T L; Ferrari, A; Sala, P; Carminati, F; Brun, R

    2001-01-01

    This NASA funded project is proceeding to develop a Monte Carlo-based computer simulation of the radiation environment in space. With actual funding only initially in place at the end of May 2000, the study is still in the early stage of development. The general tasks have been identified and personnel have been selected. The code to be assembled will be based upon two major existing software packages. The radiation transport simulation will be accomplished by updating the FLUKA Monte Carlo program, and the user interface will employ the ROOT software being developed at CERN. The end-product will be a Monte Carlo-based code which will complement the existing analytic codes such as BRYNTRN/HZETRN presently used by NASA to evaluate the effects of radiation shielding in space. The planned code will possess the ability to evaluate the radiation environment for spacecraft and habitats in Earth orbit, in interplanetary space, on the lunar surface, or on a planetary surface such as Mars. Furthermore, it will be useful in the design and analysis of experiments such as ACCESS (Advanced Cosmic-ray Composition Experiment for Space Station), which is an Office of Space Science payload currently under evaluation for deployment on the International Space Station (ISS). FLUKA will be significantly improved and tailored for use in simulating space radiation in four ways. First, the additional physics not presently within the code that is necessary to simulate the problems of interest, namely the heavy ion inelastic processes, will be incorporated. Second, the internal geometry package will be replaced with one that will substantially increase the calculation speed as well as simplify the data input task. Third, default incident flux packages that include all of the different space radiation sources of interest will be included. Finally, the user interface and internal data structure will be melded together with ROOT, the object-oriented data analysis infrastructure system. Beyond

  16. First global WCRP shortwave surface radiation budget dataset

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Charlock, T. P.; Staylor, W. F.; Pinker, R. T.; Laszlo, I.; Ohmura, A.; Gilgen, H.; Konzelman, T.; Dipasquale, R. C.; Moats, C. D.

    1995-01-01

    Shortwave radiative fluxes that reach the earth's surface are key factors that influence atmospheric and oceanic circulations as well as surface climate. Yet, information on these fluxes is meager. Surface site data are generally available from only a limited number of observing stations over land. Much less is known about the large-scale variability of the shortwave radiative fluxes over the oceans, which cover most of the globe. Recognizing the need to produce global-scale fields of such fluxes for use in climate research, the World Climate Research Program has initiated activities that led to the establishment of the Surface Radiation Budget Climatology Project with the ultimate goal to determine various components of the surface radiation budget from satellite data. In this paper, the first global products that resulted from this activity are described. Monthly and daily data on a 280-km grid scale are available. Samples of climate parameters obtainable from the dataset are presented. Emphasis is given to validation and limitations of the results. For most of the globe, satellite estimates have bias values between +/- 20 W/sq m and root mean square (rms) values are around 25 W/sq m. There are specific regions with much larger uncertainties however.

  17. The radiation from apertures in curved surfaces

    NASA Technical Reports Server (NTRS)

    Pathak, P. H.; Kouyoumjian, R. G.

    1973-01-01

    The geometrical theory of diffraction is extended to treat the radiation from apertures or slots in convex, perfectly-conducting surfaces. It is assumed that the tangential electric field in the aperture is known so that an equivalent, infinitesimal source can be defined at each point in the aperture. Surface rays emanate from this source which is a caustic of the ray system. A launching coefficient is introduced to describe the excitation of the surface ray modes. If the field radiated from the surface is desired, the ordinary diffraction coefficients are used to determine the field of the rays shed tangentially from the surface rays. The field of the surface ray modes is not the field on the surface; hence if the mutual coupling between slots is of interest, a second coefficient related to the launching coefficient must be employed. In the region adjacent to the shadow boundary, the component of the field directly radiated from the source is presented by Fock-type functions. In the illuminated region the incident radiation from the source (this does not include the diffracted field components) is treated by geometrical optics. This extension of the geometrical theory of diffraction is applied to calculate the radiation from slots on elliptic cylinders, spheres and spheroids.

  18. Reverse surface-polariton cherenkov radiation.

    PubMed

    Tao, Jin; Wang, Qi Jie; Zhang, Jingjing; Luo, Yu

    2016-01-01

    The existence of reverse Cherenkov radiation for surface plasmons is demonstrated analytically. It is shown that in a metal-insulator-metal (MIM) waveguide, surface plasmon polaritons (SPPs) excited by an electron moving at a speed higher than the phase velocity of SPPs can generate Cherenkov radiation, which can be switched from forward to reverse direction by tuning the core thickness of the waveguide. Calculations are performed in both frequency and time domains, demonstrating that a radiation pattern with a backward-pointing radiation cone can be achieved at small waveguide core widths, with energy flow opposite to the wave vector of SPPs. Our study suggests the feasibility of generating and steering electron radiation in simple plasmonic systems, opening the gate for various applications such as velocity-selective particle detections. PMID:27477061

  19. Reverse surface-polariton cherenkov radiation

    NASA Astrophysics Data System (ADS)

    Tao, Jin; Wang, Qi Jie; Zhang, Jingjing; Luo, Yu

    2016-08-01

    The existence of reverse Cherenkov radiation for surface plasmons is demonstrated analytically. It is shown that in a metal-insulator-metal (MIM) waveguide, surface plasmon polaritons (SPPs) excited by an electron moving at a speed higher than the phase velocity of SPPs can generate Cherenkov radiation, which can be switched from forward to reverse direction by tuning the core thickness of the waveguide. Calculations are performed in both frequency and time domains, demonstrating that a radiation pattern with a backward-pointing radiation cone can be achieved at small waveguide core widths, with energy flow opposite to the wave vector of SPPs. Our study suggests the feasibility of generating and steering electron radiation in simple plasmonic systems, opening the gate for various applications such as velocity-selective particle detections.

  20. Reverse surface-polariton cherenkov radiation.

    PubMed

    Tao, Jin; Wang, Qi Jie; Zhang, Jingjing; Luo, Yu

    2016-01-01

    The existence of reverse Cherenkov radiation for surface plasmons is demonstrated analytically. It is shown that in a metal-insulator-metal (MIM) waveguide, surface plasmon polaritons (SPPs) excited by an electron moving at a speed higher than the phase velocity of SPPs can generate Cherenkov radiation, which can be switched from forward to reverse direction by tuning the core thickness of the waveguide. Calculations are performed in both frequency and time domains, demonstrating that a radiation pattern with a backward-pointing radiation cone can be achieved at small waveguide core widths, with energy flow opposite to the wave vector of SPPs. Our study suggests the feasibility of generating and steering electron radiation in simple plasmonic systems, opening the gate for various applications such as velocity-selective particle detections.

  1. Reverse surface-polariton cherenkov radiation

    PubMed Central

    Tao, Jin; Wang, Qi Jie; Zhang, Jingjing; Luo, Yu

    2016-01-01

    The existence of reverse Cherenkov radiation for surface plasmons is demonstrated analytically. It is shown that in a metal-insulator-metal (MIM) waveguide, surface plasmon polaritons (SPPs) excited by an electron moving at a speed higher than the phase velocity of SPPs can generate Cherenkov radiation, which can be switched from forward to reverse direction by tuning the core thickness of the waveguide. Calculations are performed in both frequency and time domains, demonstrating that a radiation pattern with a backward-pointing radiation cone can be achieved at small waveguide core widths, with energy flow opposite to the wave vector of SPPs. Our study suggests the feasibility of generating and steering electron radiation in simple plasmonic systems, opening the gate for various applications such as velocity-selective particle detections. PMID:27477061

  2. Parametric Study of Variable Emissivity Radiator Surfaces

    NASA Technical Reports Server (NTRS)

    Grob, Lisa M.; Swanson, Theodore D.

    2000-01-01

    The goal of spacecraft thermal design is to accommodate a high function satellite in a low weight and real estate package. The extreme environments that the satellite is exposed during its orbit are handled using passive and active control techniques. Heritage passive heat rejection designs are sized for the hot conditions and augmented for the cold end with heaters. The active heat rejection designs to date are heavy, expensive and/or complex. Incorporating an active radiator into the design that is lighter, cheaper and more simplistic will allow designers to meet the previously stated goal of thermal spacecraft design Varying the radiator's surface properties without changing the radiating area (as with VCHP), or changing the radiators' views (traditional louvers) is the objective of the variable emissivity (vary-e) radiator technologies. A parametric evaluation of the thermal performance of three such technologies is documented in this paper. Comparisons of the Micro-Electromechanical Systems (MEMS), Electrochromics, and Electrophoretics radiators to conventional radiators, both passive and active are quantified herein. With some noted limitations, the vary-e radiator surfaces provide significant advantages over traditional radiators and a promising alternative design technique for future spacecraft thermal systems.

  3. Mitigation of radiation induced surface contamination

    DOEpatents

    Klebanoff, Leonard E.; Stulen, Richard H.

    2003-01-01

    A process for mitigating or eliminating contamination and/or degradation of surfaces having common, adventitious atmospheric contaminants adsorbed thereon and exposed to radiation. A gas or a mixture of gases is introduced into the environment of a surface(s) to be protected. The choice of the gaseous species to be introduced (typically a hydrocarbon gas, water vapor, or oxygen or mixtures thereof) is dependent upon the contaminant as well as the ability of the gaseous species to bind to the surface to be protected. When the surface and associated bound species are exposed to radiation reactive species are formed that react with surface contaminants such as carbon or oxide films to form volatile products (e.g., CO, CO.sub.2) which desorb from the surface.

  4. Surface contributions to radiated sound power.

    PubMed

    Marburg, Steffen; Lösche, Eric; Peters, Herwig; Kessissoglou, Nicole

    2013-06-01

    This paper presents a method to identify the surface areas of a vibrating structure that contribute to the radiated sound power. The surface contributions of the structure are based on the acoustic radiation modes and are computed for all boundaries of the acoustic domain. The surface contributions are compared to the acoustic intensity, which is a common measure for near-field acoustic energy. Sound intensity usually has positive and negative values that correspond to energy sources and sinks on the surface of the radiating structure. Sound from source and sink areas partially cancel each other and only a fraction of the near-field acoustic energy reaches the far-field. In contrast to the sound intensity, the surface contributions are always positive and no cancelation effects exist. The technique presented here provides a method to localize the relevant radiating surface areas on a vibrating structure. To illustrate the method, the radiated sound power from a baffled square plate is presented. PMID:23742325

  5. Root surface temperature rises in vitro during root canal obturation using hybrid and microseal techniques.

    PubMed

    Lipski, Mariusz

    2005-04-01

    The aim of this in vitro study was to measure the temperature rise on the outer surface of roots during filling with hybrid technique and Microseal. Twenty extracted human maxillary and mandibular premolars with a single canal were randomly divided into two groups of 10 teeth each. In the first group, the teeth were filled with hybrid technique (thermomechanical compaction with Engine Plugger used following lateral condensation of the apical part of the canal), the second group was filled using Microseal. After root canal obturation the filling material was removed and the obturation procedure was repeated. A total of 20 obturations in each group were performed. Temperature changes were measured using a thermal imaging camera. The temperature of certain regions of the mesial surface was analyzed and the highest temperature values were recorded. Statistical analysis was performed using the Mann-Whitney U test. The mean increase of temperature during the hybrid technique with Engine Plugger was 23.8 degrees C, while during Microseal it was significantly lower (p = 0.000001) at 5.5 degrees C. The temperature rise generated by Microseal was below the critical level and should not damage supporting structures, however, the hybrid technique generated a relatively high temperature rise that may cause periodontal tissue damage.

  6. Surface wave effects on microstrip antenna radiation

    NASA Astrophysics Data System (ADS)

    Roudot, Bertrand; Mosig, Juan; Gardiol, Fred

    1988-03-01

    Surface waves play a significant role in phased arrays of microstrip antennas, and cannot be neglected, as has been habitually done in the use of approximate models. Attention is presently given to sophisticated integral equation techniques furnishing accurate design data for the analysis and synthesis of microstrip patch antennas, taking into account surface waves and losses within the structure. Secondary radiation produced by scattering of the surface waves on the border of a finite dielectric substrate is determined by these means.

  7. Profilometric analysis of root surfaces after using various polishing agents

    PubMed Central

    Jana, Anjan; Chakraborty, Abhijit; Pal, Tamal Kanti; Datta, Someswar

    2016-01-01

    Background: Polishing is an important step in oral prophylaxis procedure which retards further accumulation of plaque on the root surfaces. Though polishing was done with various abrasive particles with different sizes over a long period of time, it was never been highlighted to evaluate the ideal polishing material and the particle size that would produce the ideal surface smoothness (Ra <0.2 μm). Materials and Methods: The present study was carried out on 70 periodontally involved, caries-free extracted human teeth from 42 patients. All the teeth were collected from the region of incisors, canines, and premolars. In vitro scaling and root planing were performed by piezoelectric scaler and Gracey's area specific curettes, respectively. All the teeth were grouped at random into control and experimental. The collections of abrasive materials were done directly from the market, and the different particle sizes were prepared in the laboratory. Experimentation: The polishing was done at a constant speed of 200 rpm with cylindrical nylon bristle brush followed by rubber prophy cup. Each group belonging to control and experimental was subjected to profilometric study for evaluation of surface roughness. Results: Regular polishing abrasives are not able to produce the surface smoothness of our desire level (i.e., Ra <0.2 μm), which can be achieved only by submicron-sized particles. Conclusion: Regular size polishing particles available in the market (>5 μm) are not able to produce the surface smoothness <0.2 μm. Only, submicron sized particles are able to produce the desired smoothness. PMID:27041833

  8. Atmospheric radiation model for water surfaces

    NASA Technical Reports Server (NTRS)

    Turner, R. E.; Gaskill, D. W.; Lierzer, J. R.

    1982-01-01

    An atmospheric correction model was extended to account for various atmospheric radiation components in remotely sensed data. Components such as the atmospheric path radiance which results from singly scattered sky radiation specularly reflected by the water surface are considered. A component which is referred to as the virtual Sun path radiance, i.e. the singly scattered path radiance which results from the solar radiation which is specularly reflected by the water surface is also considered. These atmospheric radiation components are coded into a computer program for the analysis of multispectral remote sensor data over the Great Lakes of the United States. The user must know certain parameters, such as the visibility or spectral optical thickness of the atmosphere and the geometry of the sensor with respect to the Sun and the target elements under investigation.

  9. What is the Best Root Surface Treatment for Avulsed Teeth?

    PubMed Central

    Tuna, Elif B; Yaman, Duygu; Yamamato, Seiko

    2014-01-01

    Dental avulsion is the most severe type of traumatic tooth injuries since it causes damage to several structures and results in avulsion of the tooth from its socket. Management protocols for avulsed teeth should include management of the pulp and periodontal ligament (PDL) cells in order to improve the long-term prognosis and survival of these teeth. The prognosis of the treatment as well as the survival of an avulsed tooth depends on intrinsic and extrinsic factors, such as the duration of the tooth’s extra-alveolar period, replantation time, the type of storage medium, PDL status and duration of splinting. Recent research has led to the development of storage media. However, there is not yet a single solution that fulfills all requirements to be considered as the ideal medium for temporary storage of avulsed teeth, and research on this field should carry on. On the other hand in case of delayed replantation, due to the great risk of tooth loss after avulsion, different root surface treatments have been proposed to prevent and delay root resorption before replantation. For this purpose, researchers have applied some different root surface treatment modalities in delayed replantation of avulsed teeth. Several protocols have been used to maintain PDL viability; some involve fluorides, steroids, sodium alendronate, enamel matrix derivatives (EMD) and basic fibroblast growth factor (bFGF, FGF-2). Among these applications, bFGF shows promising results in the regeneration of natural tooth structures and tissues. Better understanding of mechanism of bFGF may help to improve new technologies of regeneration of tooth structures. PMID:25317212

  10. Europa Surface Radiation Environment for Lander Assessment

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Sturner, Steven J.

    2006-01-01

    The Jovian magnetospheric particle environment at Europa's surface is critical to assessment of landed astrobiological experiments in three respects: (1) the landing site must be chosen for the best prospects for detectable organic or inorganic signs of Life, e.g. regions of freshly emergent flows from the subsurface; (2) lander systems must reach the surface through the Jovian magnetospheric environment and operate long enough on the surface to return useful data; (3) lander instrumentation must be capable of detecting signs of life in the context of the local environmental radiation and associated chemistry. The Galileo, Voyager, and Pioneer missions have provided a wealth of data on energetic particle intensities throughout the Jovian magnetosphere including from many flybys of Europa. cumulative radiation dosages for spacecraft enroute to Europa can be well characterized, but knowledge of the surface radiation environment is very limited. Energetic electrons should primarily impact the trailing hemisphere with decreasing intensity towards the center of the leading hemisphere and are the most significant radiation component down to meter depths in the surface regolith due to secondary interactions. Observed surface distribution for sulfates is suggestive of electron irradiation but may have alternative interpretations. Having much-larger magnetic gyroradii than electrons, energetic protons and heavier ions irradiate more of the global surface. The particular orientations of electron, proton, and ion gyromotion would project into corresponding directional (e.g., east-west) anisotropies of particle flu into the surface. Particular topographic features at the landing site may therefore offer shielding from part of the incident radiation.

  11. Bioremediation of phenolic compounds from water with plant root surface peroxidases

    SciTech Connect

    Adler, P.R.; Arora, R.; El Ghaouth, A.

    1994-09-01

    Peroxidases have been shown to polymerize phenolic compounds, thereby removing them from solution by precipitation. Others have studied the role of root surface associated peroxidases as a defense against fungal root pathogens; however, their use in detoxification of organic pollutants in vivo at the root surface has not been studied. Two plant species, waterhyacinth [Eichhornia crassipes (C. Mart) Solms-Laub.] and tomato (Lycopersicon esculentum L.), were tested for both in vitro and in vivo peroxidase activity on the root surface. In vitro studies indicated that root surface peroxidase activities were 181 and 78 nmol tetraguaiacol formed min{sup -1} g{sup -1} root fresh wt., for tomato and waterhyacinth, respectively. Light microscope studies revealed that guaiacol was polymerized in vivo at the root surface. Although peroxidase was evenly distributed on tomato roots, it was distributed patchily on waterhyacinth roots. In vitro studies using gas chromatography-mass spectrometry (GC-MS) showed that the efficiency of peroxidase to polymerize phenols vary with phenolic compound. We suggest that plants may be utilized as a source of peroxidases for removal of phenolic compounds that are on the EPA priority pollutant list and that root surface peroxidases may minimize the absorption of phenolic compounds into plants by precipitating them at the root surface. In this study we have identified a new use for root-associated proteins in ecologically engineering plant systems for bioremediation of phenolic compounds in the soil and water environment. 25 refs., 2 figs., 2 tabs.

  12. Root hairs aid soil penetration by anchoring the root surface to pore walls

    PubMed Central

    Bengough, A. Glyn; Loades, Kenneth; McKenzie, Blair M.

    2016-01-01

    The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3–3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0–1.5g cm−3). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm−3 soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm−3 soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm−3). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm−3 soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. PMID:26798027

  13. Ultraviolet Radiation on the Surface of Mars

    NASA Technical Reports Server (NTRS)

    Catling, D. C.; Cockell, C. S.; McKay, C. P.

    1999-01-01

    An evaluation of the ultraviolet (UV) flux incident on the Martian surface is important for a number of issues. UV-induced photolysis of water changes the chemistry of the soil and atmosphere, inducing its oxidizing nature. Alternatively, UV may directly affect surface chemistry by generating silicate defects. UV also rapidly degrades organic material delivered by meteoritic infall. Consequently, UV affects the overall chemistry of the Martian surface and atmosphere. The extent of UV breakdown of organic molecules is also relevant to concerns regarding contaminants on lander or rover surfaces that could interfere with life-detection experiments causing "false positives". The radiation flux at a point on the surface of Mars depends on factors such as cloud cover, atmospheric dust loading, season, local time, and latitude. Previously, the UV spectrum incident on the surface of Mars has been calculated from a simple radiative transfer model. Limitations of this earlier model include no accounting for the effect of dust, which may be a perennial constituent of the atmosphere, and also the use of gas absorption data measured at room temperature that overestimate absorption for lower Martian temperatures. We present an updated model for UV radiation (200-400 nm) that incorporates dust and more recent data for the solar spectrum, gas absorption, and UV surface albedo. Additional information is contained in the original extended abstract.

  14. Tooth root growth impairment after mantle radiation in long-term survivors of Hodgkin's disease

    SciTech Connect

    McGinnis, J.P. Jr.; Hopkins, K.P.; Thompson, E.I.; Hustu, H.O.

    1985-10-01

    The tooth root growth impairment that resulted from 35 to 37 Gy mantle port radiation in 47 long-term survivors of childhood Hodgkin's disease was quantified and related to specific age groups and categories of teeth. Root measurements of the mandibular permanent canines, first and second premolars, and first and second molars were made from sequential panoramic radiographs taken at the time of radiation therapy and after the closure of root apexes. The severity of root growth impairment was greatest in patients who received radiation during the early stages of odontogenesis. With later stages of odontogenesis, and as the age increased at the time of treatment, less impairment occurred. The potential difficulties of using repeated panoramic radiographs to assess tooth lengths in longitudinal studies also were discussed.

  15. A Radiation Analysis of Lunar Surface Habitats

    NASA Astrophysics Data System (ADS)

    de Angelis, G.; Wilson, J. W.; Tripathi, R. K.; Clowdsley, M. S.

    2002-01-01

    An analysis is performed on the radiation environment found on the surface of the Moon, and applied to different possible lunar base mission scenarios. An optimization technique has been used to minimize the astronaut radiation exposure and at the same time control the effect of shielding, in terms of mass addition and material choice, as a mission cost driver. The optimization process performs minimization of mass along all phases of a mission scenario, considered in terms of time frame, equipment, location, crew characteristics and performance required, radiation exposure annual and career limit constraints (those proposed in NCRP 132), and implementation of the ALARA principle. On the lunar surface the most important contribution to radiation exposure is given by background Galactic Cosmic Rays (GCR) particles, and by locally induced particles, mostly neutrons, generated by interaction between GCRs and surface material. In this environment manned habitats are to host future crews involved in the construction and/or in the utilization of moon based infrastructure. Three different kinds of lunar missions are considered in the analysis, Moon Base Construction Phase, during which astronauts are on the surface just to build an outpost for future resident crews, Moon Base Outpost Phase, during which astronaut crews are resident but continuing exploration and installation activities, and Moon Base Routine Phase, with shifting resident crews. In each scenario various kinds of habitats, from very simple shelters to more complex bases, are considered in detail (e.g, shape, thickness, materials, etc) with considerations of various shielding strategies. The results for all scenarios clearly showed that the direct exposure to the space environment like in transfers and EVAs phases gives the most of the dose, with the proposed shielded habitats and shelters giving quite a good protection from radiation. Material choice and distribution in the habitable sections of spacecraft

  16. Evaluation of Arctic broadband surface radiation measurements

    NASA Astrophysics Data System (ADS)

    Matsui, N.; Long, C. N.; Augustine, J.; Halliwell, D.; Uttal, T.; Longenecker, D.; Niebergall, O.; Wendell, J.; Albee, R.

    2012-02-01

    The Arctic is a challenging environment for making in-situ surface radiation measurements. A standard suite of radiation sensors is typically designed to measure incoming and outgoing shortwave (SW) and thermal infrared, or longwave (LW), radiation. Enhancements may include various sensors for measuring irradiance in narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that keep sensors and shading devices trained on the sun along its diurnal path. High quality measurements require striking a balance between locating stations in a pristine undisturbed setting free of artificial blockage (such as from buildings and towers) and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data in the Arctic include solar tracker malfunctions, rime/frost/snow deposition on the protective glass domes of the radiometers and operational problems due to limited operator access in extreme weather conditions. In this study, comparisons are made between the global and component sum (direct [vertical component] + diffuse) SW measurements. The difference between these two quantities (that theoretically should be zero) is used to illustrate the magnitude and seasonality of arctic radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both SW and LW measurements. Solutions to these operational problems that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols are proposed.

  17. Arabidopsis thaliana sku mutant seedlings show exaggerated surface-dependent alteration in root growth vector.

    PubMed

    Rutherford, R; Masson, P H

    1996-08-01

    Roots of wild-type Arabidopsis thaliana seedlings in the Wassilewskija (WS) and Landsberg erecta (Ler) ecotypes often grow aslant on vertical agar surfaces. Slanted root growth always occurs to the right of the gravity vector when the root is viewed through the agar surface, and is not observed in the Columbia ecotype. Right-slanted root growth is surface-dependent and does not result directly from directional environmental stimuli or gradients in the plane of skewing. We have isolated two partially dominant mutations in WS (sku1 and sku2) that show an exaggerated right-slanting root-growth phenotype on agar surfaces. The right-slanting root-growth phenotype of wild-type and mutant roots is not the result of diagravitropism or of an alteration in root gravitropism. It is accompanied by a left-handed rotation of the root about its axis within the elongation zone, the rate of which positively correlates with the degree of right-slanted curvature. Our data suggest that the right-slanting root growth phenotype results from an endogenous structural asymmetry that expresses itself by a directional root-tip rotation.

  18. Arabidopsis thaliana sku mutant seedlings show exaggerated surface-dependent alteration in root growth vector

    NASA Technical Reports Server (NTRS)

    Rutherford, R.; Masson, P. H.

    1996-01-01

    Roots of wild-type Arabidopsis thaliana seedlings in the Wassilewskija (WS) and Landsberg erecta (Ler) ecotypes often grow aslant on vertical agar surfaces. Slanted root growth always occurs to the right of the gravity vector when the root is viewed through the agar surface, and is not observed in the Columbia ecotype. Right-slanted root growth is surface-dependent and does not result directly from directional environmental stimuli or gradients in the plane of skewing. We have isolated two partially dominant mutations in WS (sku1 and sku2) that show an exaggerated right-slanting root-growth phenotype on agar surfaces. The right-slanting root-growth phenotype of wild-type and mutant roots is not the result of diagravitropism or of an alteration in root gravitropism. It is accompanied by a left-handed rotation of the root about its axis within the elongation zone, the rate of which positively correlates with the degree of right-slanted curvature. Our data suggest that the right-slanting root growth phenotype results from an endogenous structural asymmetry that expresses itself by a directional root-tip rotation.

  19. [Improvement of root parameters in land surface model (LSM )and its effect on the simulated results].

    PubMed

    Cai, Kui-ye; Liu, Jing-miao; Zhang, Zheng-qiu; Liang, Hong; He, Xiao-dong

    2015-10-01

    In order to improve root parameterization in land surface model, the sub-model for root in CERES-Maize was coupled in the SSiB2 after calibrating of maize parameters in SSiB2. The effects of two improved root parameterization schemes on simulated results of land surface flux were analyzed. Results indicated that simulation accuracy of land surface flux was enhanced when the root module provided root depth only with the SSiB2 model (scheme I). Correlation coefficients between observed and simulated values of latent flux and sensible flux increased during the whole growing season, and RMSE of linear fitting decreased. Simulation accuracy of CO2 flux was also enhanced from 121 days after sowing to mature period. On the other hand, simulation accuracy of the flux was enhanced when the root module provided root depth and root length density simultaneously for the SSiB2 model (scheme II). Compared with the scheme I, the scheme II was more comprehensive, while its simulation accuracy of land surface flux decreased. The improved root parameterization in the SSiB2 model was better than the original one, which made simulated accuracy of land-atmospheric flux improved. The scheme II overestimated root relative growth in the surface layer soil, so its simulated accuracy was lower than that of the scheme I. PMID:26995920

  20. Root Surface Bio-modification with Erbium Lasers- A Myth or a Reality??

    PubMed

    Lavu, Vamsi; Sundaram, Subramoniam; Sabarish, Ram; Rao, Suresh Ranga

    2015-01-01

    The objective of this literature review was to critically review the evidence available in the literature regarding the expediency of erbium family of lasers for root bio modification as a part of periodontal therapy. The literature search was performed on the Pubmed using MeSH words such as "lasers/therapeutic use, scaling, dental calculus, tooth root/anatomy and histology, ultrasonic therapy". The studies were screened and were grouped as follows: those evaluating a) efficacy for calculus removal with the Erbium family of laser b) root surface changes following Er YAG and Er Cr YSGG application c) comparative studies of the Er YAG, Er Cr YSGG lasers versus conventional methods of root surface modification d) Bio compatibility of root surface following Erbium laser treatment e) Studies on the combined efficacy of laser root modification with conventional methods towards root surface bio-modification f) Studies on effectiveness of root surface bio-modification prior to root coverage procedures. In conclusion, the erbium family has a proven anti-bacterial action, predictable calculus removal, minimal root substance removal, and appears to favor cell attachment. The Erbium family of lasers appears to be a useful adjunct for the management of periodontal disease. PMID:25713635

  1. Root Surface Bio-modification with Erbium Lasers- A Myth or a Reality??

    PubMed

    Lavu, Vamsi; Sundaram, Subramoniam; Sabarish, Ram; Rao, Suresh Ranga

    2015-01-01

    The objective of this literature review was to critically review the evidence available in the literature regarding the expediency of erbium family of lasers for root bio modification as a part of periodontal therapy. The literature search was performed on the Pubmed using MeSH words such as "lasers/therapeutic use, scaling, dental calculus, tooth root/anatomy and histology, ultrasonic therapy". The studies were screened and were grouped as follows: those evaluating a) efficacy for calculus removal with the Erbium family of laser b) root surface changes following Er YAG and Er Cr YSGG application c) comparative studies of the Er YAG, Er Cr YSGG lasers versus conventional methods of root surface modification d) Bio compatibility of root surface following Erbium laser treatment e) Studies on the combined efficacy of laser root modification with conventional methods towards root surface bio-modification f) Studies on effectiveness of root surface bio-modification prior to root coverage procedures. In conclusion, the erbium family has a proven anti-bacterial action, predictable calculus removal, minimal root substance removal, and appears to favor cell attachment. The Erbium family of lasers appears to be a useful adjunct for the management of periodontal disease.

  2. Effects of nature of cooling surface on radiator performance

    NASA Technical Reports Server (NTRS)

    Parsons, S R; Kleinschmidt, R V

    1921-01-01

    This report discusses the effects of roughness, smoothness, and cleanness of cooling surfaces on the performance of aeronautic radiators, as shown by experimental work, with different conditions of surface, on (1) heat transfer from a single brass tube and from a radiator; (2) pressure drop in an air stream in a single brass tube and in a radiator; (3) head resistance of a radiator; and (4) flow of air through a radiator. It is shown that while smooth surfaces are better than rough, the surfaces usually found in commercial radiators do not differ enough to show marked effect on performance, provided the surfaces are kept clean.

  3. Polysaccharide extraction from Sphallerocarpus gracilis roots by response surface methodology.

    PubMed

    Ma, Tingting; Sun, Xiangyu; Tian, Chengrui; Luo, Jiyang; Zheng, Cuiping; Zhan, Jicheng

    2016-07-01

    The extraction process of Sphallerocarpus gracilis root polysaccharides (SGRP) was optimized using response surface methodology with two methods [hot-water extraction (HWE) and ultrasonic-assisted extraction (UAE)]. The antioxidant activities of SGRP were determined, and the structural features of the untreated materials (HWE residue and UAE residue) and the extracted polysaccharides were compared by scanning electron microscopy. Results showed that the optimal UAE conditions were extraction temperature of 81°C, extraction time of 1.7h, liquid-solid ratio of 17ml/g, ultrasonic power of 300W and three extraction cycles. The optimal HWE conditions were 93°C extraction temperature, 3.6h extraction time, 21ml/g liquid-solid ratio and three extraction cycles. UAE offered a higher extraction yield with a shorter time, lower temperature and a lower solvent consumption compared with HWE, and the extracted polysaccharides possessed a higher antioxidant capacity. Therefore, UAE could be used as an alternative to conventional HWE for SGRP extraction. PMID:27032488

  4. Holmium:YAG laser: effects of various treatments on root surface topography and acid resistance

    NASA Astrophysics Data System (ADS)

    Holt, Raleigh A.; Nordquist, Robert E.

    1996-04-01

    The effects of Holmium:YAG laser energy with and without a topical fluoride mixture (resin to NaF) was compared with two types of topical fluorides on surface topography and resistance to acid destruction of root surfaces. Scanning electron microscopy (SEM) was used to evaluate the effects of the selected treatments on surface topography before acid exposure. Toluidine blue dye was used to test the permeability of root surfaces after acid exposures. SEM examinations of the dentinal root surfaces showed consistently smooth surfaces with tubule closures when using topical resin to fluoride and HO:YAG laser treatment; in contrast, HO:YAG laser energy treatment alone exhibited increased roughness of root surfaces. Topical fluoride applications alone presented surfaces similar to untreated control sites. Toluidine blue dye penetration into root surfaces of the fluoride/laser-treated root surfaces showed significantly less dye penetration after acid exposures than controls and other treatment protocols. The results of this study indicate that the resin-fluoride application and holmium:YAG irradiation effectively produced increased smoothness and increased resistance to destruction of root surfaces in human extracted teeth under these in vitro conditions.

  5. How and why do root apices sense light under the soil surface?

    PubMed Central

    Mo, Mei; Yokawa, Ken; Wan, Yinglang; Baluška, František

    2015-01-01

    Light can penetrate several centimeters below the soil surface. Growth, development and behavior of plant roots are markedly affected by light despite their underground lifestyle. Early studies provided contrasting information on the spatial and temporal distribution of light-sensing cells in the apical region of root apex and discussed the physiological roles of plant hormones in root responses to light. Recent biological and microscopic advances have improved our understanding of the processes involved in the sensing and transduction of light signals, resulting in subsequent physiological and behavioral responses in growing root apices. Here, we review current knowledge of cellular distributions of photoreceptors and their signal transduction pathways in diverse root tissues and root apex zones. We are discussing also the roles of auxin transporters in roots exposed to light, as well as interactions of light signal perceptions with sensing of other environmental factors relevant to plant roots. PMID:26442084

  6. Biophysical characterization and surface radiation balance

    NASA Technical Reports Server (NTRS)

    Walter-Shea, Elizabeth A.; Blad, Blaine L.; Mesarch, Mark A.; Hays, Cynthia J.; Starks, Patrick J.

    1993-01-01

    The Kursk 1991 Experiment (KUREX-91) was conducted as one of a suite of international studies to develop capabilities to monitor global change. The studies were designed specifically to understand the earth's land-surface vegetation and atmospheric boundary layer interaction. An intensive field campaign was conducted at a site near Kursk, Russia during the month of July in 1991 by a team of international scientists to aid in the understanding of land-surface-atmosphere interactions in an agricultural/grassland setting. We were one of several teams of scientists participating at KUREX-91 at the Streletskaya Steppe Researve near Kursk, Russia. The main goals of our research were to: (1) characterize biophysical properties of the prairie vegetation; and (2) to characterize radiation regime through measurements and from estimates derived from canopy bidirectional reflectance data. Four objectives were defined to achieve these goals: (1) determine dependence of leaf optical properties on leaf water potential of some dominant species in discrete wavebands in the visible, near-infrared, and mid-infrared (spanning 0.4-2.3 microns range); (2) characterize the effective leaf area index (LAI) and leaf angle distribution of prairie vegetation; (3) characterize the radiation regime of the prairie vegetation through measures of the radiation balance components; and (4) examine, develop, and test methods for estimating albedo, APAR, and LAI from canopy bidirectional reflectance data. Papers which were the result of the research efforts are included.

  7. Annual Cycle of Surface Longwave Radiation

    NASA Technical Reports Server (NTRS)

    Mlynczak, Pamela E.; Smith, G. Louis; Wilber, Anne C.; Stackhouse, Paul W.

    2011-01-01

    The annual cycles of upward and downward longwave fluxes at the Earth s surface are investigated by use of the NASA/GEWEX Surface Radiation Budget Data Set. Because of the immense difference between the heat capacity of land and ocean, the surface of Earth is partitioned into these two categories. Principal component analysis is used to quantify the annual cycles. Over land, the first principal component describes over 95% of the variance of the annual cycle of the upward and downward longwave fluxes. Over ocean the first term describes more than 87% of these annual cycles. Empirical orthogonal functions show the corresponding geographical distributions of these cycles. Phase plane diagrams of the annual cycles of upward longwave fluxes as a function of net shortwave flux show the thermal inertia of land and ocean.

  8. A QTL Study for Regions Contributing to Arabidopsis thaliana Root Skewing on Tilted Surfaces.

    PubMed

    Vaughn, Laura M; Masson, Patrick H

    2011-07-01

    Plant root systems must grow in a manner that is dictated by endogenous genetic pathways, yet sensitive to environmental input. This allows them to provide the plant with water and nutrients while navigating a heterogeneous soil environment filled with obstacles, toxins, and pests. Gravity and touch, which constitute important cues for roots growing in soil, have been shown to modulate root architecture by altering growth patterns. This is illustrated by Arabidopsis thaliana roots growing on tilted hard agar surfaces. Under these conditions, the roots are exposed to both gravity and touch stimulation. Consequently, they tend to skew their growth away from the vertical and wave along the surface. This complex growth behavior is believed to help roots avoid obstacles in nature. Interestingly, A. thaliana accessions display distinct growth patterns under these conditions, suggesting the possibility of using this variation as a tool to identify the molecular mechanisms that modulate root behavior in response to their mechanical environment. We have used the Cvi/Ler recombinant inbred line population to identify quantitative trait loci that contribute to root skewing on tilted hard agar surfaces. A combination of fine mapping for one of these QTL and microarray analysis of expression differences between Cvi and Ler root tips identifies a region on chromosome 2 as contributing to root skewing on tilted surfaces, potentially by modulating cell wall composition.

  9. Surface daytime net radiation estimation using artificial neural networks

    DOE PAGES

    Jiang, Bo; Zhang, Yi; Liang, Shunlin; Zhang, Xiaotong; Xiao, Zhiqiang

    2014-11-11

    Net all-wave surface radiation (Rn) is one of the most important fundamental parameters in various applications. However, conventional Rn measurements are difficult to collect because of the high cost and ongoing maintenance of recording instruments. Therefore, various empirical Rn estimation models have been developed. This study presents the results of two artificial neural network (ANN) models (general regression neural networks (GRNN) and Neuroet) to estimate Rn globally from multi-source data, including remotely sensed products, surface measurements, and meteorological reanalysis products. Rn estimates provided by the two ANNs were tested against in-situ radiation measurements obtained from 251 global sites between 1991–2010more » both in global mode (all data were used to fit the models) and in conditional mode (the data were divided into four subsets and the models were fitted separately). Based on the results obtained from extensive experiments, it has been proved that the two ANNs were superior to linear-based empirical models in both global and conditional modes and that the GRNN performed better and was more stable than Neuroet. The GRNN estimates had a determination coefficient (R2) of 0.92, a root mean square error (RMSE) of 34.27 W·m–2 , and a bias of –0.61 W·m–2 in global mode based on the validation dataset. In conclusion, ANN methods are a potentially powerful tool for global Rn estimation.« less

  10. Regional Climatology and Surface Radiation Budget

    NASA Technical Reports Server (NTRS)

    Wilber, Anne C.; Smith, G. Louis; Stackhouse, Paul W., Jr.

    1999-01-01

    The climatology and surface radiation budget (SRB) of a region are intimately related. This paper presents a brief examination of this relationship. An 8-year surface radiation budget data set has been developed based on satellite measurements. In that data set and in this paper a region is defined as a quasi-square 2.5o in latitude and approximately the same physical distance in longitude. A pilot study by Wilber et al. (1998) showed a variety of behaviors of the annual cycles for selected regions. Selected desert regions form a loop in a specific part of the plot, with large NLW and large NSW. Tropical wet regions form much smaller loops in a different part of the plot, with small NLW and large NSW. For regions selected in high latitude the annual cycles form nearly linear figures in another part of the plot. The question arises as to whether these trajectories are characteristic of the climatology of the region or simply the behavior of the few regions selected from the set of 6596 regions. In order to address this question, it is necessary to classify the climatology of the each region, e.g. as classified by Koeppen (1936) or Trenwarthe and Horne (1980). This paper presents a method of classifying climate of the regions on the basis of the surface radiation behavior such that the results are very similar to the classification of Trenwarthe and Horne. The characteristics of the annual cycle of SRB components can then be investigated further, based on the climate classification of each region.

  11. Growth and Movement of Spot Inoculated Rhizobium meliloti on the Root Surface of Alfalfa 1

    PubMed Central

    Caetano-Anollés, Gustavo; Wrobel-Boerner, Elizabeth; Bauer, Wolfgang D.

    1992-01-01

    Inoculum droplets of approximately 10 nanoliter volume and containing about 10 Rhizobium meliloti cells were placed onto the root surface of alfalfa seedlings in plastic growth pouches at either the root tip, the position of the smallest emergent root hairs, or at a site midway between these points. The droplets were initially confined to an area of about 0.2 square millimeter at the point of application. By 48 and 96 hours after inoculation, the inoculum bacteria and their progeny were distributed over several centimeters of the root between the initial site of deposition and the growing root tip, reaching densities of 103 to 104 bacteria per centimeter near the site of initial deposition and decreasing exponentially from that point toward the root tip. Graphite particles deposited on the root surface close to the growing tip were similarly distributed along the root length by 48 and 96 hours, suggesting that passive displacement by root cell elongation was primarily responsible for the spread of bacteria. A nonmotile mutant of R. meliloti colonized alfalfa roots to the same extent as the wild type and was usually distributed in the same manner, indicating that bacterial motility contributed little under these conditions to long distance spread of the bacteria. However, when applied in low numbers, R. meliloti mutants defective in motility or chemotaxis were considerably less efficient in initiating nodules near the point of inoculation than the wild type. This implies that motility and/or chemotaxis contribute significantly to local exploration for suitable infection sites. Almost all nodules on the primary root formed within a few millimeters of the spot-inoculation site, indicating that, under our experimental conditions, movement and multiplication of R. meliloti on the root surface were not sufficient to maintain an adequate population in the infectible region of the root during root growth. PMID:16668744

  12. Er:YAG and alexandrite laser radiation propagation in the root canal and its effect on bacteria

    NASA Astrophysics Data System (ADS)

    Jelinkova, Helena; Dostalova, Tatjana; Duskova, Jana; Miyagi, Mitsunobu; Shoji, Shigeru; Sulc, Jan; Nemec, Michal

    1999-05-01

    The goal of the study was to verify differences between the alexandrite and Er:YAG laser energy distribution in the root canal and in the surrounding dentin and bone tissues. For the experiment, two lasers were prepared: the Er:YAG laser (λ=2.94 μm) with a delivery system fluorocarbon polymer-coated silver hollow glass waveguide ended by a special sapphire tip and the alexandrite laser (λ=0.75 μm) with a silicon fiber. The Er:YAG laser was operated in a free-running mode, the length of the generated pulses was 250 μsec and the output energy ranged from 100 to 350 mJ. The pulse length of the free- running alexandrite laser was 70 μsec and the output energy was ranged from 80 up to 200 mJ. For the experiment prepared root canals of molars were used. It was ascertained that the radiation of the alexandrite laser passes through the root canal and hits the surrounding tissue. Nocardia asteroids, Filaments, Micrococcus albus, Lactobacillus sp and Streptococcus sanguis colonies were treated by the Er:YAG or alexandrite laser radiation. The surface was checked by scanning electron microscopy. From the result it follows that the Er:YAG laser destroyed microbial colonies but the differences is in the depth of the affected area.

  13. X-ray photoelectron spectroscopy surface analysis of aluminum ion stress in barley roots. [Hordeum vulgare

    SciTech Connect

    Millard, M.M.; Foy, C.D.; Coradetti, C.A.; Reinsel, M.D. )

    1990-06-01

    X-ray photoelectron spectroscopy (XPS) has been used to analyze root surface changes when Dayton barley (Hordeum vulgare) (Al tolerant) and Kearney barley (Al sensitive) seedlings were grown in nutrient solution in the presence and absence of 37.0 micromolar Al. The electron spectra from root surfaces contained strong lines in order of decreasing intensity from organic forms of carbon, oxygen, and nitrogen and weak lines due to inorganic elements in the form of anions and cations on the surface. The surface composition of root tips from Kearney was C, 65.6%; 0, 26.8%; N, 4.4% and tips from Dayton was C, 72.7%; O, 23.6%; N, 1.9%, grown in the absence of aluminum. Electron lines characteristic of nitrate, potassium, chloride, phosphate were also present in the spectra from those roots. Dayton roots grown in the presence of 37.0 micromolar aluminum contained 2.1% aluminum while Kearney contained 1.3% aluminum. The ratio of aluminum to phosphate was close to 1.0. Dayton roots usually contained twice as much aluminum phosphate in the surface region as Kearney. Dayton may be less susceptible to Al toxic effects by accumulation of aluminum phosphate on the root surface which then acts as a barrier to the transport of aluminum into the interior of the roots.

  14. Effects of wastewater discharge on formation of Fe plaque on root surface and radial oxygen loss of mangrove roots.

    PubMed

    Pi, N; Tam, N F Y; Wong, M H

    2010-02-01

    Effects of wastewater discharge on radial oxygen loss (ROL), formation of iron (Fe) plaque on root surface, and their correlations in Bruguiera gymnorrhiza (L.) Poir and Excoecaria agallocha L. were investigated. ROL along a lateral root increased more rapidly in control than that in strong wastewater (with pollutant concentrations ten times of that in municipal sewage, 10NW) treatment, but less Fe plaque was formed in control for both plants. For B. gymnorrhiza receiving 10NW, Fe plaque formation was more at basal and mature zones than at root tip, while opposite trend was shown in E. agallocha. At day 0, the correlation between ROL and Fe plaque was insignificant, but negative and positive correlations were found in 10NW and control, respectively, at day 105, suggesting that more ROL was induced leading to more Fe plaque. However, excess Fe plaque also served as a 'barrier' to prevent excessive ROL in 10NW plants. PMID:19782449

  15. Validation and Spatiotemporal Analysis of CERES Surface Net Radiation Product

    DOE PAGES

    Jia, Aolin; Jiang, Bo; Liang, Shunlin; Zhang, Xiaotong; Ma, Han

    2016-01-23

    The Clouds and the Earth’s Radiant Energy System (CERES) generates one of the few global satellite radiation products. The CERES ARM Validation Experiment (CAVE) has been providing long-term in situ observations for the validation of the CERES products. However, the number of these sites is low and their distribution is globally sparse, and particularly the surface net radiation product has not been rigorously validated yet. Therefore, additional validation efforts are highly required to determine the accuracy of the CERES radiation products. In this study, global land surface measurements were comprehensively collected for use in the validation of the CERES netmore » radiation (Rn) product on a daily (340 sites) and a monthly (260 sites) basis, respectively. The validation results demonstrated that the CERES Rn product was, overall, highly accurate. The daily validations had a Mean Bias Error (MBE) of 3.43 W·m−2, Root Mean Square Error (RMSE) of 33.56 W·m−2, and R2 of 0.79, and the monthly validations had an MBE of 3.40 W·m−2, RMSE of 25.57 W·m−2, and R2 of 0.84. The accuracy was slightly lower for the high latitudes. Following the validation, the monthly CERES Rn product, from March 2000 to July 2014, was used for a further analysis. We analysed the global spatiotemporal variation of the Rn, which occurred during the measurement period. In addition, two hot spot regions, the southern Great Plains and south-central Africa, were then selected for use in determining the driving factors or attribution of the Rn variation. We determined that Rn over the southern Great Plains decreased by −0.33 W·m−2 per year, which was mainly driven by changes in surface green vegetation and precipitation. In south-central Africa, Rn decreased at a rate of −0.63 W·m−2 per year, the major driving factor of which was surface green vegetation.« less

  16. Thermographic assessment of heat generated on the root surface during post space preparation.

    PubMed

    Hussey, D L; Biagioni, P A; McCullagh, J J; Lamey, P J

    1997-05-01

    The mechanical preparation of a post space in a root filled tooth is commonly carried out using rotating instruments in a slow handpiece. This procedure creates frictional heat which may be transferred to the root surface. In this investigation, the temperature changes on the root surface of 12 root filled, extracted human premolar teeth during preparation of post spaces were analysed using an infrared thermal imaging camera. A rotational speed of 8000 r.p.m. was used and the teeth were prepared with size 2 and 3 Peeso reamers and a red Parapost drill to the optimal length. The results indicate that very large temperatures are generated on the root surface and that this is greatest during the Parapost preparation stage. The long-term clinical effects of post space preparation by engine driven drills would warrant further investigation.

  17. Radiation guiding with surface plasmon polaritons

    NASA Astrophysics Data System (ADS)

    Han, Zhanghua; Bozhevolnyi, Sergey I.

    2013-01-01

    Surface plasmon polaritons (SPPs) are electromagnetic (EM) modes propagating along metal-dielectric interfaces, in which surface collective excitations of free electrons in the metal are coupled to evanescent EM fields in the dielectric. Various SPP modes can be supported by flat and curved, single and multiple surfaces, exhibiting remarkable properties, including the possibility of concentrating EM fields beyond the diffraction limit, i.e. on the nanoscale, while enhancing local field strengths by several orders of magnitude. This unique feature of SPP modes, along with the ever-increasing demands for miniaturization of photonic components and circuits, generates an exponentially growing interest in SPP-mediated radiation guiding and SPP-based waveguide components. Here we review the current status of this rapidly developing field, starting with a brief presentation of the main planar SPP modes along with the techniques employed for their excitation and manipulation by sets of nanoparticles. We then describe in detail various SPP-based waveguide configurations that ensure two-dimensional mode confinement in the plane perpendicular to the propagation direction and compare their characteristics. Excitation of SPP waveguide modes and recent progress in the development of SPP-based waveguide components are also discussed, concluding with our outlook on challenges and possible future developments in this field.

  18. Parametrization of net radiation at the surface using data from the Wangara experiment

    SciTech Connect

    Edson, R T

    1980-07-01

    Hourly Wangara boundary layer data (Clark et al., 1971) was used to substantiate previously derived empirical equations of the surface radiation budget. These equations only require measurements taken by a surface observer in order to be evaluated. A parameterization was made for infrared (IR) radiation. From this procedure, a residual radiation was obtained from the measured daytime net radiation data in order to approximate short wave (SW) radiation. Diurnal trends in radiation and other related meteorological parameters were also evaluated. For IR radiation, the Brunt equation was found to adequately represent effective radiation without clouds. IR attenuation (K-values) of 0.89, 0.64, and 0.51 were calculated for low, middle, and high clouds, respectively. A modification of Beer's Law was derived to evaluate the residual radiation under clear skies as suggested by Flowers et al. (1969) for SW radiation. With the surface albedo assumed at 0.15, a mean turbidity coefficient of 0.16 was determined. Also, the square root of the optical air mass was found to best represent the data in this equation. An analysis of SW cloud attenuation coefficients (C-values) from the residual radiation proved inconclusive. Of considerable importance is the finding that cloud attenuation of the residual radiation behaved nonlinearly. Whereas solutions as high as the fourth order fit the data at noon, quadratic solutions fit well near sunset and sunrise. Overall; relative deviations during the day of the combined parameterization were approximately 20% at noon and just less than 30% for periods up to one hour before sunset or sunrise. Predictions within these one-hour periods, however, contained considerable error, partially due, to the scatter and small magnitude of the measurements. Diurnal trends in surface radiation and other meteorological parameters were established.

  19. Lunar surface fission power supplies: Radiation issues

    SciTech Connect

    Houts, M.G.; Lee, S.K.

    1994-07-01

    A lunar space fission power supply shield that uses a combination of lunar regolith and materials brought from earth may be optimal for early lunar outposts and bases. This type of shield can be designed such that the fission power supply does not have to be moved from its landing configuration, minimizing handling and required equipment on the lunar surface. Mechanisms for removing heat from the lunar regolith are built into the shield, and can be tested on earth. Regolith activation is greatly reduced compared with a shield that uses only regolith, and it is possible to keep the thermal conditions of the fission power supply close to these seen in free space. For a well designed shield, the additional mass required to be brought fro earth should be less than 1000 kg. Detailed radiation transport calculations confirm the feasibility of such a shield.

  20. Thermal and microstructural effects of nanosecond pulsed Nd:YAG laser irradiation on tooth root surface

    NASA Astrophysics Data System (ADS)

    Wilder-Smith, Petra B. B.; Arrastia-Jitosho, Anna-Marie A.; Grill, G.; Liaw, Lih-Huei L.; Berns, Michael W.

    1995-05-01

    Plaque, calculus and altered cementum removal by scaling and root planing is a fundamental procedure in periodontal treatment. However, the residual smear layer contains cytotoxic and inflammatory mediators which adversely affect healing. Chemical smear layer removal is also problematic. In previous investigations effective smear layer removal was achieved using long pulsed irradiation at 1.06 (mu) . However, laser irradiation was not adequate as an alternative to scaling and root planing procedures and concurrent temperature rises exceeded thermal thresholds for pulpal and periodontal safety. It was the aim of this study to determine whether nanosecond pulsed irradiation at 1.06 (mu) could be used as an alternative or an adjunct to scaling and root planing. Sixty freshly extracted teeth were divided as follows: 5 control, 5 root planed only, 25 irradiated only, 25 root planed and irradiated. Irradiation was performed at fluences of 0.5 - 2.7 J/cm2, total energy densities of 12 - 300 J/cm2, frequencies of 2 - 10 Hz using the Medlite (Continuum) laser. Irradiation-induced thermal events were recorded using a thermocouple within the root canal and a thermal camera to monitor surface temperatures. SEM demonstrated effective smear layer removal with minimal microstructural effects. Surface temperatures increased minimally (< 3 C) at all parameters, intrapulpal temperature rises remained below 4 C at 2 and 5 Hz, F < 0.5 J/cm2. Without prior scaling and root planing, laser effects did not provide an adequately clean root surface.

  1. Sorption of fibronectin to human root surfaces in vitro

    SciTech Connect

    Mendieta, C.; Caravana, C.; Fine, D.H. )

    1990-05-01

    The purpose of this study was to determine the conditions that favor the sorption and retention of human plasma fibronectin to cementum. Rectangular root segments prepared from teeth extracted for orthodontic reasons were mounted on a capillary pipette and immersed in solutions of {sup 125}I fibronectin for assay of cementum sorption under various conditions. Kinetic studies showed sorption to be rapid, with 77% of the maximum fibronectin sorption occurring within 1 minute. Fibronectin sorption was reduced when added in conjunction with serum and was inhibited by monovalent ions (such as sodium), but enhanced in the presence of divalent cations (such as calcium). Exposure of cementum to serum partially blocked subsequent sorption of fibronectin, while cementum bound fibronectin was eluted by subsequent exposure to serum. Treatment of cementum with citric acid pH 1.1 (4 minutes) followed by 5% sodium hypochlorite (5 minutes) caused a significant increase in fibronectin sorption with maximum retention upon subsequent exposure to serum (P less than 0.05). Fibronectin sorption to cementum was: rapid, electrostatic in nature, competitive, reversible, Ca+(+)-facilitated, and maximized by prior treatment of the root with citric acid and sodium hypochlorite. It is concluded that sorption of fibronectin to cementum can be achieved for clinical gain; however, conditions of application can significantly influence both accumulation and subsequent release of root sorbed material.

  2. Calculus removal on a root cement surface by ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Kraft, Johan F.; Vestentoft, Kasper; Christensen, Bjarke H.; Løvschall, Henrik; Balling, Peter

    2008-01-01

    Ultrashort-pulse-laser ablation of dental calculus (tartar) and cement is performed on root surfaces. The investigation shows that the threshold fluence for ablation of calculus is a factor of two to three times smaller than that of a healthy root cement surface. This indicates that ultrashort laser pulses may provide an appropriate tool for selective removal of calculus with minimal damage to the underlying root cement. Future application of an in situ profiling technique allows convenient on-line monitoring of the ablation process.

  3. Toward Improved Solar Irradiance Forecasts: Derivation of Downwelling Surface Shortwave Radiation in Arizona from Satellite

    NASA Astrophysics Data System (ADS)

    Kim, Chang Ki; Holmgren, William F.; Stovern, Michael; Betterton, Eric A.

    2016-07-01

    Over the past few decades, substantial progress has been made in the retrieval of surface shortwave radiation from satellite measurements for the Earth's energy budget as well as solar energy applications. We present a new algorithm to derive the downwelling surface shortwave radiation for the Southwestern US using geostationary satellite products. A look-up table generated by the Goddard Space Flight Center Radiative Transfer Model is employed to derive the shortwave radiation at the ground by comparing observed and modeled top of atmosphere shortwave albedo. The algorithm was compared to ground observation stations at three locations, such as the University of Arizona, the University of Nevada, Las Vegas, and Desert Rock, NV. For all sky conditions, the average values of root-mean-square error between the instantaneous estimates and in situ measurements ranged from 84.2 to 89.4 W m-2 and were 30 W m-2 when evaluated on daily time scales. The error statistics were considerably better for clear sky than for cloudy sky. The average values of instantaneous root-mean-square error for the clear-sky conditions range from 39.4 to 43.7 W m-2, while average root-mean-square error for the cloudy-sky conditions is between 137.0 and 141.2 W m-2.

  4. Surface daytime net radiation estimation using artificial neural networks

    SciTech Connect

    Jiang, Bo; Zhang, Yi; Liang, Shunlin; Zhang, Xiaotong; Xiao, Zhiqiang

    2014-11-11

    Net all-wave surface radiation (Rn) is one of the most important fundamental parameters in various applications. However, conventional Rn measurements are difficult to collect because of the high cost and ongoing maintenance of recording instruments. Therefore, various empirical Rn estimation models have been developed. This study presents the results of two artificial neural network (ANN) models (general regression neural networks (GRNN) and Neuroet) to estimate Rn globally from multi-source data, including remotely sensed products, surface measurements, and meteorological reanalysis products. Rn estimates provided by the two ANNs were tested against in-situ radiation measurements obtained from 251 global sites between 1991–2010 both in global mode (all data were used to fit the models) and in conditional mode (the data were divided into four subsets and the models were fitted separately). Based on the results obtained from extensive experiments, it has been proved that the two ANNs were superior to linear-based empirical models in both global and conditional modes and that the GRNN performed better and was more stable than Neuroet. The GRNN estimates had a determination coefficient (R2) of 0.92, a root mean square error (RMSE) of 34.27 W·m–2 , and a bias of –0.61 W·m–2 in global mode based on the validation dataset. In conclusion, ANN methods are a potentially powerful tool for global Rn estimation.

  5. Surface Disinfestation of Resting Spores of Plasmodiophora brassicae Used to Infect Hairy Roots of Brassica spp.

    PubMed

    Asano, T; Kageyama, K; Hyakumachi, M

    1999-04-01

    ABSTRACT Resting spores of Plasmodiophora brassicae were surface-disinfested by treatment with 2% chloramine-T for 20 min and then with an antibiotic solution (1,000 ppm of colistin sulfate, 1,000 ppm of vancomycin hydrochloride, and 6,000 ppm of cefotaxime sodium) for 1 day. The disinfested resting spores were used to inoculate hairy roots of cabbage (Brassica oleracea var. capitata cv. Fuji Wase), Chinese cabbage (B. pekinensis cv. Musou Hakusai), turnip (B. rapa var. rapifera cv. Wase Okabu), and rape (B. napus line Dc 119). Differences among hosts in susceptibility to clubroot in hairy roots were evident. Chinese cabbage and turnip hairy roots supported the highest percentages of root hair infection (53.3 to 80%) and the greatest production of zoosporangial groups (8.5 to 32.5 per root). Moreover, gall formation was observed only on Chinese cabbage and turnip hairy roots. The morphology of zoo-sporangia, plasmodia, and resting spores in diseased hairy roots was found to be identical to that in infected intact plants by both light and scanning electron microscopy. Pathogenicity tests confirmed the infectivity of resting spores produced in hairy roots. Thus, the hairy root culture technique should prove useful as a dual culture system for P. brassicae.

  6. Root surface temperature rise of mandibular first molar during root canal filling with high-temperature thermoplasticized Gutta-Percha in the dog.

    PubMed

    Lipski, M; Woźniak, K; Lichota, D; Nowicka, A

    2011-01-01

    This in vitro study evaluated the temperature rise on the outer root surface of the mandibular first molar following root canal filling using the high-temperature, thermoplasticized, Gutta-Percha technique (HTTG) (BeeFill) in the dog. Twelve extracted dog mandibular first molars were used. After root canal preparation, the teeth were filled with thermoplasticized Gutta-Percha and root canal sealer. Temperature changes on the vestibular surfaces of the mesial and distal roots of mandibular first molars were measured using a thermal imaging camera. The results of this in vitro study showed that using HTTG to fill mandibular first molars in dogs produces a safe temperature rise on the root surface and, therefore, should not damage the periodontal ligament and/or surrounding tissues.

  7. Deposition of corrosion products from dowels on human dental root surfaces measured with proton microprobe technique

    NASA Astrophysics Data System (ADS)

    Brune, D.; Brunell, G.; Lindh, U.

    1982-06-01

    Distribution of copper, mercury and zinc on human teeth root surfaces adjacent to dowels of gold alloy or brass as well as dowels of brass in conjunction with an amalgam crown has been measured with a proton microprobe using PIXE techniques. Upper limits of the contents of gold and silver on the root surfaces were established. Pronounced concentration profiles of copper and zinc were observed on the root surfaces of teeth prepared with dowels of brass. The dowel of gold alloy revealed only zinc deposition. The major part of copper on the root surfaces is assumed to arise from corrosion of the dowels, and has been transported to the surface by diffusion through the dential tubuli. Zinc in the volume analysed is a constituent of dentin tissue as well as a corrosion product of the brass dowel. Part of the zinc level could also be ascribed to erosion of the zinc phosphate cement matrix. The volumes analysed were (25×25×25)μm 3. The levels of copper, mercury and zinc on the tooth root surfaces attained values up to about 200, 20 and 600 ppm, respectively.

  8. Status of the Space Radiation Monte Carlos Simulation Based on FLUKA and ROOT

    NASA Technical Reports Server (NTRS)

    Andersen, Victor; Carminati, Federico; Empl, Anton; Ferrari, Alfredo; Pinsky, Lawrence; Sala, Paola; Wilson, Thomas L.

    2002-01-01

    The NASA-funded project reported on at the first IWSSRR in Arona to develop a Monte-Carlo simulation program for use in simulating the space radiation environment based on the FLUKA and ROOT codes is well into its second year of development, and considerable progress has been made. The general tasks required to achieve the final goals include the addition of heavy-ion interactions into the FLUKA code and the provision of a ROOT-based interface to FLUKA. The most significant progress to date includes the incorporation of the DPMJET event generator code within FLUKA to handle heavy-ion interactions for incident projectile energies greater than 3GeV/A. The ongoing effort intends to extend the treatment of these interactions down to 10 MeV, and at present two alternative approaches are being explored. The ROOT interface is being pursued in conjunction with the CERN LHC ALICE software team through an adaptation of their existing AliROOT software. As a check on the validity of the code, a simulation of the recent data taken by the ATIC experiment is underway.

  9. Isolation of a novel mutant gene for soil-surface rooting in rice (Oryza sativa L.)

    PubMed Central

    2013-01-01

    Background Root system architecture is an important trait affecting the uptake of nutrients and water by crops. Shallower root systems preferentially take up nutrients from the topsoil and help avoid unfavorable environments in deeper soil layers. We have found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. In this study, we examined the genetic and physiological characteristics of this mutant. Results The primary roots of the mutant showed no gravitropic response from the seedling stage on, whereas the gravitropic response of the shoots was normal. Segregation analyses by using an F2 population derived from a cross between the soil-surface rooting mutant and wild-type Nipponbare indicated that the trait was controlled by a single recessive gene, designated as sor1. Fine mapping by using an F2 population derived from a cross between the mutant and an indica rice cultivar, Kasalath, revealed that sor1 was located within a 136-kb region between the simple sequence repeat markers RM16254 and 2935-6 on the terminal region of the short arm of chromosome 4, where 13 putative open reading frames (ORFs) were found. We sequenced these ORFs and detected a 33-bp deletion in one of them, Os04g0101800. Transgenic plants of the mutant transformed with the genomic fragment carrying the Os04g0101800 sequence from Nipponbare showed normal gravitropic responses and no soil-surface rooting. Conclusion These results suggest that sor1, a rice mutant causing soil-surface rooting and altered root gravitropic response, is allelic to Os04g0101800, and that a 33-bp deletion in the coding region of this gene causes the mutant phenotypes. PMID:24280269

  10. Measurement of solar radiation at the Earth's surface

    NASA Technical Reports Server (NTRS)

    Bartman, F. L.

    1982-01-01

    The characteristics of solar energy arriving at the surface of the Earth are defined and the history of solar measurements in the United States presented. Radiation and meteorological measurements being made at solar energy meteorological research and training sites and calibration procedures used there are outlined. Data illustrating the annual variation in daily solar radiation at Ann Arbor, Michigan and the diurnal variation in radiation at Albuquerque, New Mexico are presented. Direct normal solar radiation received at Albuquerque is contrasted with that received at Maynard, Massachusetts. Average measured global radiation for a period of one year for four locations under clear skies, 50% cloud cover, and 100% cloud cover is given and compared with the solar radiation at the top of the atmosphere. The May distribution of mean daily direct solar radiation and mean daily global solar radiation over the United States is presented. The effects of turbidity on the direct and circumsolar radiation are shown.

  11. Comparison of Root Surface Roughness Produced By Hand Instruments and Ultrasonic Scalers: An Invitro Study

    PubMed Central

    Das, Swarga Jyoti; Sonowal, Saindhya Tora; Chawla, Jitendra

    2015-01-01

    Background Instrumentation on tooth surface for debridement of hard and soft debris forms the basis of periodontal therapy. This involves periodic removal of accumulated material using different methods of instrumentation. An ideal instrument should eliminate all the deposits from the root surfaces with no or minimal alteration of the natural morphology. Aim To compare the root surface roughness after root planing performed with gracey curette and by ultrasonic scalers (Satelec P-5 Booster) set at different power modes. Materials and Methods The root surface roughness and its surface microtopography resulting from the use of Gracey curette, ultrasonic instrument at low, medium and high power setting on 35 healthy premolars extracted for orthodontic treatment purpose were examined using Optical Profilometer and the surface topography was assessed using Field Emission Microscope. Statistical Analysis Analysis of variance (ANOVA) test was used to observe the variance in a particular variable is partitioned into components attributable to different sources of variation. Duncan multiple range tests were used to determine whether three or more means differ significantly. Results and Conclusion The mean roughness was found to be the highest in group where Scaling and Root Planing (SRP) was performed using ultrasonic scaler at low power mode (3.03±1.54 μm) whereas the lowest surface roughness was seen on the samples where SRP was performed using ultrasonic scaler at medium power mode. The surface roughness in group where SRP was performed with ultrasonic scaler at high power mode (2.22±0.74μm) was found to be similar to that of group in which root planing was carried out using curette (2.24±1.71μm). PMID:26675445

  12. Mobile phone radiation inhibits Vigna radiata (mung bean) root growth by inducing oxidative stress.

    PubMed

    Sharma, Ved Parkash; Singh, Harminder Pal; Kohli, Ravinder Kumar; Batish, Daizy Rani

    2009-10-15

    During the last couple of decades, there has been a tremendous increase in the use of cell phones. It has significantly added to the rapidly increasing EMF smog, an unprecedented type of pollution consisting of radiation in the environment, thereby prompting the scientists to study the effects on humans. However, not many studies have been conducted to explore the effects of cell phone EMFr on growth and biochemical changes in plants. We investigated whether EMFr from cell phones inhibit growth of Vigna radiata (mung bean) through induction of conventional stress responses. Effects of cell phone EMFr (power density: 8.55 microW cm(-2); 900 MHz band width; for 1/2, 1, 2, and 4 h) were determined by measuring the generation of reactive oxygen species (ROS) in terms of malondialdehyde and hydrogen peroxide (H(2)O(2)) content, root oxidizability and changes in levels of antioxidant enzymes. Our results showed that cell phone EMFr significantly inhibited the germination (at > or =2 h), and radicle and plumule growths (> or =1 h) in mung bean in a time-dependent manner. Further, cell phone EMFr enhanced MDA content (indicating lipid peroxidation), and increased H(2)O(2) accumulation and root oxidizability in mung bean roots, thereby inducing oxidative stress and cellular damage. In response to EMFr, there was a significant upregulation in the activities of scavenging enzymes, such as superoxide dismutases, ascorbate peroxidases, guaiacol peroxidases, catalases and glutathione reductases, in mung bean roots. The study concluded that cell phone EMFr inhibit root growth of mung bean by inducing ROS-generated oxidative stress despite increased activities of antioxidant enzymes.

  13. Influence of low-intensity laser radiation upon the microflora of carious cavities and root canal

    NASA Astrophysics Data System (ADS)

    Shumilovitch, Bogdan R.; Nekrylov, Valery; Mazo, Leonid

    1995-04-01

    Laser stomatology- a relatively young branch of stomatology -has been developing actively lately. Bactericidal action of laser radiation enables to use it widely for processing carious cavities and root canals in the treatment of caries and its complications. 113 patients were studied by us. The 40 patients had antiseptic procedure of the caries cavity and then the procedure of laser therapy, so micro-organisms were found out in 26% cases. The 63 patients had antiseptic procedure only, so micro-organisms were found out in 70% cases. Control group were consisted of patients, where laser therapy was carried out without antiseptic remedies.

  14. Surface Radiation from GOES: A Physical Approach; Preprint

    SciTech Connect

    Habte, A.; Sengupta, M.; Wilcox, S.

    2012-09-01

    Models to compute Global Horizontal Irradiance (GHI) and Direct Normal Irradiance (DNI) have been in development over the last 3 decades. These models can be classified as empirical or physical, based on the approach. Empirical models relate ground based observations with satellite measurements and use these relations to compute surface radiation. Physical models consider the radiation received from the earth at the satellite and create retrievals to estimate surface radiation. While empirical methods have been traditionally used for computing surface radiation for the solar energy industry the advent of faster computing has made operational physical models viable. The Global Solar Insolation Project (GSIP) is an operational physical model from NOAA that computes GHI using the visible and infrared channel measurements from the GOES satellites. GSIP uses a two-stage scheme that first retrieves cloud properties and uses those properties in a radiative transfer model to calculate surface radiation. NREL, University of Wisconsin and NOAA have recently collaborated to adapt GSIP to create a 4 km GHI and DNI product every 30 minutes. This paper presents an outline of the methodology and a comprehensive validation using high quality ground based solar data from the National Oceanic and Atmospheric Administration (NOAA) Surface Radiation (SURFRAD) (http://www.srrb.noaa.gov/surfrad/sitepage.html) and Integrated Surface Insolation Study (ISIS) http://www.srrb.noaa.gov/isis/isissites.html), the Solar Radiation Research Laboratory (SRRL) at National Renewable Energy Laboratory (NREL), and Sun Spot One (SS1) stations.

  15. Can the KTP laser change the cementum surface of healthy and diseased teeth providing an acceptable root surface for fibroblast attachment?

    NASA Astrophysics Data System (ADS)

    Mailhot, Jason M.; Garnick, Jerry J.

    1996-04-01

    The purpose of our research is to determine the effects of KTP laser on root cementum and fibroblast attachment. Initial work has been completed in testing the effect of different energy levels on root surfaces. From these studies optimal energy levels were determined. In subsequent studies the working distance and exposure time required to obtain significant fibroblast attachment to healthy cementum surfaces were investigated. Results showed that lased cemental surfaces exhibited changes in surface topography which ranged from a melted surface to an apparent slight fusion of the surface of the covering smear layer. When the optimal energy level was used, fibroblasts demonstrate attachment on the specimens, resulting in the presence of a monolayer of cells on the control surfaces as well as on the surfaces lased with this energy level. The present study investigates the treatment of pathological root surfaces and calculus with a KTP laser utilizing these optimal parameters determine previously. Thirty single rooted teeth with advanced periodontal disease and ten healthy teeth were obtained, crowns were sectioned and roots split longitudinally. Forty test specimens were assigned into 1 of 4 groups; pathologic root--not lased, pathologic root--lased, root planed root and health root planed root. Human gingival fibroblasts were seeded on specimens and cultured for 24 hours. Specimens were processed for SEM. The findings suggest that with the KTP laser using a predetermined energy level applied to pathological root surfaces, the lased surfaces provided an unacceptable surface for fibroblast attachment. However, the procedural control using healthy root planed surfaces did demonstrate fibroblast attachment.

  16. In Vivo Delivery of Tinospora cordifolia Root Extract Preventing Radiation-Induced Dystrophies in Mice Ovaries

    PubMed Central

    Sharma, Riddhi

    2015-01-01

    Unconscious and unplanned radiation exposures are a severe threat to gonads particularly ovaries. The present study aims at finding radioprotective effect of Tinospora cordifolia (Willd.) Miers root extract (TCRE) in ovaries. Swiss albino mice were divided into four groups: Group 1 served as “normal” and is administered double distilled water and Group 2 is given TCRE with optimum dosage selected as 75 mg/mice. Group 3 serving the purpose of “irradiated control” were exposed to 2.5 Gy gamma radiation. Group 4 (experimental) were administered optimum dosage of TCRE with prior exposure to 2.5 Gy gamma radiation. Follicle cell counts were scored at autopsy intervals of 24 hrs, 3 days, 7 days, 15 days, and 30 days after gamma irradiation. To understand the mechanism of radioprotection, lipid peroxidation (LPO) and glutathione (GSH) levels were also measured in all groups. TCRE supplementation rendered significant protection to ovaries by restoring follicle counts; it also reduced LPO levels and increased GSH levels in ovaries. It implies that TCRE administration protects ovaries against radiation exposure. PMID:26357520

  17. In Vivo Delivery of Tinospora cordifolia Root Extract Preventing Radiation-Induced Dystrophies in Mice Ovaries.

    PubMed

    Sharma, Riddhi

    2015-01-01

    Unconscious and unplanned radiation exposures are a severe threat to gonads particularly ovaries. The present study aims at finding radioprotective effect of Tinospora cordifolia (Willd.) Miers root extract (TCRE) in ovaries. Swiss albino mice were divided into four groups: Group 1 served as "normal" and is administered double distilled water and Group 2 is given TCRE with optimum dosage selected as 75 mg/mice. Group 3 serving the purpose of "irradiated control" were exposed to 2.5 Gy gamma radiation. Group 4 (experimental) were administered optimum dosage of TCRE with prior exposure to 2.5 Gy gamma radiation. Follicle cell counts were scored at autopsy intervals of 24 hrs, 3 days, 7 days, 15 days, and 30 days after gamma irradiation. To understand the mechanism of radioprotection, lipid peroxidation (LPO) and glutathione (GSH) levels were also measured in all groups. TCRE supplementation rendered significant protection to ovaries by restoring follicle counts; it also reduced LPO levels and increased GSH levels in ovaries. It implies that TCRE administration protects ovaries against radiation exposure. PMID:26357520

  18. Root surface acid phosphatases and their role in phosphorus assimilation by Eriophorum vaginatum

    SciTech Connect

    Kroehler, C.J.; Linkins, A.E.

    1988-01-01

    Eriophorum vaginatum is a dominant plant in much of the arctic tundra ecosystem where phosphorus is frequently a limiting nutrient. The mineralization of this organic phosphorus was thought to be principally controlled by microbial respiration, however, more recent work shows that extracellular soil phosphatases are the principal regulators. The existence of plant root and mycorrhizal surface phosphatases which are capable of hydrolyzing organic phosphorus compounds, suggests that soil organic phosphorus may be directly utilized by plants. Since E. vaginatum is a tussock forming sedge with a very dense annually produced rooting system which can exploit most of the tussock soil volume, its surface phosphatases may play a dominant role in organic phosphorus hydrolysis into inorganic phosphorus. Of equal significance would be the potential for this activity to contribute to the phosphorus nutrition through the coupling of phosphorus hydrolysis on the root and root uptake of the resultant inorganic phosphorus. Phosphatase activity was investigated and found to be uniformly distributed along the surface of the root. Kinetic analysis of the enzyme gave estimates of 9.23 mM for the apparent Km and 1.61 * 10/sup -3/ ..mu..moles mm-2 hr/sup -1/ for the apparent Vmax. Saturation values for E. vaginatum phosphatases are about 3 times higher than average soil solution organic phosphorus concentrations. 12 refs., 4 figs.

  19. Evaluation of arctic broadband surface radiation measurements

    NASA Astrophysics Data System (ADS)

    Matsui, N.; Long, C. N.; Augustine, J.; Halliwell, D.; Uttal, T.; Longenecker, D.; Nievergall, O.; Wendell, J.; Albee, R.

    2011-08-01

    The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that rotate sensors and shading devices that track the sun. High quality measurements require striking a balance between locating sensors in a pristine undisturbed location free of artificial blockage (such as buildings and towers) and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data include solar tracker malfunctions, rime/frost/snow deposition on the instruments and operational problems due to limited operator access in extreme weather conditions. In this study, a comparison is made between the global and component sum (direct [vertical component] + diffuse) shortwave measurements. The difference between these two quantities (that theoretically should be zero) is used to illustrate the magnitude and seasonality of radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both shortwave and longwave measurements. Solutions to these operational problems are proposed that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols.

  20. Evaluation of Arctic Broadband Surface Radiation Measurements

    SciTech Connect

    Matsui, N.; Long, Charles N.; Augustine, J. A.; Halliwell, D.; Uttal, Taneil; Longenecker, D.; Niebergale, J.; Wendell, J.; Albee, R.

    2012-02-24

    The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that rotate sensors and shading devices that track the sun. High quality measurements require striking a balance between locating sensors in a pristine undisturbed location free of artificial blockage (such as buildings and towers) and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data include solar tracker malfunctions, rime/frost/snow deposition on the instruments and operational problems due to limited operator access in extreme weather conditions. In this study, a comparison is made between the global and component sum (direct [vertical component] + diffuse) shortwave measurements. The difference between these two quantities (that theoretically should be zero) is used to illustrate the magnitude and seasonality of radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both shortwave and longwave measurements. Solutions to these operational problems are proposed that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols.

  1. Interaction of hyperthermia and radiation: the survival surface.

    PubMed

    Loshek, D D; Orr, J S; Solomonidis, E

    1977-12-01

    The interaction of hyperthermia and radiation on cell survival is illustrated by the increase in sensitivity to radiation caused by hyperthermia and the increase in sensitivity to hyperthermia caused by radiation. A method of expressing the total response to a combination of these two agents by means of a survival surface in three dimensions is explained and discussed. A simple mathematical model of the suface is formulated in which is a first order interaction term is separated from the two terms representing unperturbed radiation survival and unperturbed hyperthermia survival. An experiment is described in which survival data points were obtained for 77 combinations of radiation and hypertermia doses in the form of a matrix. These data points are plotted as 11 radiation survival curves and seven hyperthermia survival curves. The results are also analysed to give the parameters of the survival surface model. The model with its three components is shown to be a good approximation to the experimental results. PMID:588919

  2. Fast microstructuring of silica glasses surface by NIR laser radiation

    NASA Astrophysics Data System (ADS)

    Kostyuk, G. K.; Sergeev, M. M.; Zakoldaev, R. A.; Yakovlev, E. B.

    2015-05-01

    The glass surface microstructuring technology using laser radiation with NIR wavelength (λ=1.064 μm) was revealed in this work. Glass plates were placed on the cellular graphite surface. Focused laser radiation passed through the glass plate and interacted with cellular graphite. The radiation heated the graphite surface and thus the high temperature influenced the back side of the glass plate. After consecutive laser scans, having certain periods and interruptions of laser radiation, the microstructures with depth ~0.5 μm were formed. Besides, in this work we suggested the method to calculate optical characteristics of formed elements. It was experimentally shown that these microstructures could be used to form phase diffraction gratings (PDGs) and random phase plates (RPPs). We experimentally demonstrated the possibility of these elements being used as RPPs which are suitable for multimode laser radiation homogenization and as PDGs which are suitable for laser simultaneous processing of metal films.

  3. Combined surface radiation and free convection in cavities

    SciTech Connect

    Balaji, C.; Venkateshan, S.P. )

    1994-04-01

    The combined surface radiation and free convection problem are numerically investigated at low or moderate temperature levels for cavities with A in the range of 2-20. The correlations for heat convection and heat radiation across the cavity is given, which showed that correlation for radiation is superior to the parallel plate formula. The temperature profiles are obtained by solving flow equations which accounted the effect of turbulence. 11 refs.

  4. Effect of phosphorus levels on the protein profiles of secreted protein and root surface protein of rice.

    PubMed

    Shinano, Takuro; Yoshimura, Tomoko; Watanabe, Toshihiro; Unno, Yusuke; Osaki, Mitsuru; Nanjo, Yohei; Komatsu, Setsuko

    2013-11-01

    Plant roots are complicated organs that absorb water and nutrients from the soil. Roots also play an essential role in protecting plants from attack by soil pathogens and develop a beneficial role with some soil microorganisms. Plant-derived rhizosphere proteins (e.g., root secretory proteins and root surface binding proteins) are considered to play important roles in developing mutual relationships in the rhizosphere. In the rhizosphere, where plant roots meet the surrounding environment, it has been suggested that root secretory protein and root surface binding protein are important factors. Furthermore, it is not known how the physiological status of the plant affects the profile of these proteins. In this study, rice plants were grown aseptically, with or without phosphorus nutrition, and proteins were obtained from root bathing solution (designated as root secretory proteins) and obtained using 0.2 M CaCl2 solution (designated as root surface binding proteins). The total number of identified proteins in the root bathing solution was 458, and the number of root surface binding proteins was 256. More than half of the proteins were observed in both fractions. Most of the proteins were categorized as either having signal peptides or no membrane transport helix sites. The functional categorization suggested that most of the proteins seemed to have secretory pathways and were involved in defense/disease-related functions. These characteristics seem to be unique to rhizosphere proteins, and the latter might be part of the plants strategy to defeat pathogens in the soil. The low phosphorus treatment significantly increased the number of pathogenesis-related proteins in the root secretory proteins, whereas the change was small in the case of the root surface binding proteins. The results suggested that the roots are actively and selectively secreting protein into the rhizosphere. PMID:24083427

  5. Effects of root planing procedures with hand instrument or erbium, chromium:yttrium-scandium-gallium-garnet laser irradiation on the root surfaces: a comparative scanning electron microscopy study.

    PubMed

    Hakki, Sema S; Berk, Gizem; Dundar, Niyazi; Saglam, Mehmet; Berk, Nukhet

    2010-05-01

    The purpose of this study was to investigate the efficiency of hand instrumentation and laser irradiation on calculus removal from the root surfaces, in vitro. Thirty-two human teeth, extracted for periodontal reasons, were used in this study. Root surfaces of single-rooted teeth were treated by different methods including (1) conventional hand instruments; (2) hand instruments and tetracycline-hydrochloride (Tet-HCl); (3) erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation, setting I (short pulse); (4) Er,Cr:YSGG laser irradiation, setting II (long pulse). Three premolar teeth, extracted for orthodontic reasons, served as control. The morphology of the root surfaces was evaluated by light and scanning electron microscopy. Energy dispersive X-ray (EDX) analysis was performed to compare the mineral content of root surfaces treated with hand instrumentation and lasing procedures. The results of this study demonstrated that all treatments were efficient in calculus removal from the root surfaces. Thermal changes, including melting and carbonization, were not observed in either lasing procedure. The surface was rougher in the laser groups than in the groups treated with hand instruments. Moreover, roughness was greater in the long-pulse laser setting than in the short-pulse setting. While increased calcium (Ca) and decreased phosphate (P) (weight concentration percent) were observed in all treatments when compared with the control, laser procedures resulted in a more similar mineral content than in the groups treated with hand instruments. Based on these findings, laser procedures, when used in appropriate settings, are capable of performing scaling and root planing in the treatment of periodontitis. It may be concluded that short pulse laser may be more suitable for the micro-morphology of the root surface. However, additional in vitro and clinical studies are necessary to clarify the success of laser in periodontal therapy. PMID:19219484

  6. Root-surface phosphatase activity in shrublands across a European gradient: effects of warming.

    PubMed

    Estiarte, M; Peuuelas, J; Sardans, J; Emmett, B A; Sowerby, A; Beier, C; Schmidt, I K; Tietema, A; Van Meeteren, M J M; Kovacs-Lang, E; Mathe, P; De Angelis, P; De Dato, G

    2008-01-01

    Root-surface phosphatase activities were measured in natural and semi-natural shrublands across an European climatic gradient of temperature and rainfall including Wales (WL), Denmark (DK), Netherlands (NL), Hungary (HU), Italy (IT) and Spain (SP). In each site a warming experiment was conducted since 1999 or 2001 by means of passive night-time warming using reflective curtains that covered the vegetation at night. The treatments increased yearly average soil temperatures around 0. 8 degrees C in most of sites. Root-surface phosphatase activity values ranged between 56 mg PNP g(-1) h(-1) in IT and 3.5 mg PNP g(-1) h(-1) in HU. Warming had no effect on root-surface phosphatase activity across the sites and only in Hungary a slight increase was detected. Plants at Mediterranean sites (IT, SP) showed a higher root-surface phosphatase activity than plants at temperate sites (WL, NL, DK). We suggest it might be an adaptation of plant species evolved under Mediterranean climate that allows them a) to compensate in wet period for the decrease in phosphatase activity, and thus P uptake, during drought periods, and/or b) to benefit from soluble organic P flushes following the frequent drying-rewetting episodes experienced by soils in Mediterranean ecosystems. PMID:18831327

  7. [Fine root biomass and carbon storage in surface soil of Cinnamomum camphora plantation in rainy area of West China].

    PubMed

    Wei, Peng; Li, Xian-Wei; Fan, Chuan; Zhang, Teng-Fei; Liu, Yun-Ke; Su, Yu; Yang, Zheng-Ju

    2013-10-01

    Fine root in forest ecosystems plays an important role in global C cycle. In this study, a measurement was made on the fine root biomass and carbon storage in the surface soil (0-30 cm) of a 31 year-old Cinnamomum camphora plantation in the Rainy Area of West China in November, 2010-December, 2011. The total biomass and carbon storage of the fine roots (living and dead) in the surface soil were 1592.29 kg x hm(-2) and 660.68 kg C x hm(-2), in which, living fine roots accounted for 91.1% and 91.8% respectively. The total biomass and carbon storage of the first five order living roots and dead roots decreased significantly with increasing soil depth, and the living root biomass and carbon storage increased significantly with root order. The sum of the biomass and carbon storage of living and dead fine roots was the largest in autumn and the smallest in winter, but the biomass and carbon storage of the dead fine roots were the largest in winter and the smallest in summer. The biomass and carbon storage of the first two order roots were the largest in summer and the smallest in winter, while those of the last three order roots were the largest in autumn and the smallest in winter. The spatial heterogeneity of soil moisture and nutrients was the main factor affecting the fine root biomass and carbon storage.

  8. Radiation Exchange Between Stratus Clouds and Polar Marine Surfaces

    NASA Astrophysics Data System (ADS)

    Freese, D.; Kottmeier, Ch.

    The radiative energy exchange between arctic sea-ice and stratiform clouds is studied by means of aircraft measurements and a two-stream radiation transfer model. The data have been obtained by flights of two identically instrumented aircraft during the Radiation and Eddy Flux Experiments REFLEX I in autumn 1991 and REFLEX II in winter 1993 over the arctic marginal ice zone of Fram Strait. The instrumental equipment comprised Eppley pyranometers and pyrgeometers, which measure the solar and terrestrial upwelling and downwelling hemispheric radiation flux densities, and a line-scan-camera on one aircraft to monitor the surface structure of the sea-ice. An empirical parametrization of the albedo of partly ice-covered ocean surfaces is obtained from the data, which describes the albedo increasing linearly with the concentration of the snow-covered sea-ice and with the cosine of the sun zenith angle at sun elevations below 10°. Cloud optical parameters, such as single scattering albedo, asymmetry factor and shortwave and longwave height-dependent extinction coefficient are determined by adjusting modeled radiation flux densities to observations. We found significant influence of the multiple reflection of shortwave radiation between the ice surface and the cloud base on the radiation regime. Consistent with the data, a radiation transfer model shows that stratus clouds of 400 m thickness with common cloud parameters may double the global radiation at the surface of sea-ice compared to open water values. The total cloud-surface-albedo under these circumstances is 30% larger over sea-ice than over water. Parametrizations of the global and reflected radiation above and below stratus clouds are proposed on the basis of the measurements and modeling. The upwelling and downwelling longwave emission of stratus clouds with thicknesses of more than 500 m can be satisfactorily estimated by Stefan's law with an emissivity of nearly 1 and when the maximum air temperature within

  9. Annual Cycle of Cloud Forcing of Surface Radiation Budget

    NASA Technical Reports Server (NTRS)

    Wilber, Anne C.; Smith, G. Louis; Stackhouse, Paul W., Jr.; Gupta, Shashi K.

    2006-01-01

    The climate of the Earth is determined by its balance of radiation. The incoming and outgoing radiation fluxes are strongly modulated by clouds, which are not well understood. The Earth Radiation Budget Experiment (Barkstrom and Smith, 1986) provided data from which the effects of clouds on radiation at the top of the atmosphere (TOA) could be computed (Ramanathan, 1987). At TOA, clouds increase the reflected solar radiation, tending to cool the planet, and decrease the OLR, causing the planet to retain its heat (Ramanathan et al., 1989; Harrison et al., 1990). The effects of clouds on radiation fluxes are denoted cloud forcing. These shortwave and longwave forcings counter each other to various degrees, so that in the tropics the result is a near balance. Over mid and polar latitude oceans, cloud forcing at TOA results in large net loss of radiation. Here, there are large areas of stratus clouds and cloud systems associated with storms. These systems are sensitive to surface temperatures and vary strongly with the annual cycle. During winter, anticyclones form over the continents and move to the oceans during summer. This movement of major cloud systems causes large changes of surface radiation, which in turn drives the surface temperature and sensible and latent heat released to the atmosphere.

  10. Evaluation of Chlorine Dioxide Irrigation Solution on the Microhardness and Surface Roughness of Root Canal Dentin.

    PubMed

    Ballal, Nidambur Vasudev; Khandewal, Deepika; Karthikeyan, Saravana; Somayaji, Krishnaraj; Foschi, Federico

    2015-12-01

    The aim of this study was to evaluate the effect of chlorine dioxide and various other more common irrigation solutions on the microhardness and surface roughness of root canal dentin. Fifty human maxillary central incisors were sectioned longitudinally and treated for 1 minute with 5 ml of the following aqueous solutions (v/v%): Group 1: 13.8% chlorine dioxide, Group 2: 17% ethylene diamine tetraacetic acid (EDTA). Group 3: 7% maleic acid, Group 4: 2.5% sodium hypochlorite (5 ml/min), Group 5: Saline (control). Specimens were subjected to microhardness and surface roughness testing. Chlorine dioxide and sodium hypochlorite reduced the microhardness more than other test agents. The highest surface roughness was produced with maleic acid. Chlorine dioxide should be used cautiously during chemomechanical preparation of the root canal system in order to prevent untoward damage to the teeth. PMID:26767238

  11. Evaluation of Chlorine Dioxide Irrigation Solution on the Microhardness and Surface Roughness of Root Canal Dentin.

    PubMed

    Ballal, Nidambur Vasudev; Khandewal, Deepika; Karthikeyan, Saravana; Somayaji, Krishnaraj; Foschi, Federico

    2015-09-01

    The aim of this study was to evaluate the effect of chlorine dioxide and various other more common irrigation solutions on the microhardness and surface roughness of root canal dentin. Fifty human maxillary central incisors were sectioned longitudinally and treated for 1 minute with 5 ml of the following aqueous solutions (v/v%): Group 1:13.8% chlorine dioxide, Group 2:17% ethylene diamine tetraacetic acid (EDTA). Group 3: 7% maleic acid, Group 4: 2.5% sodium hypochlorite (5ml/min), Group 5: Saline (control). Specimens were subjected to microhardness and surface roughness testing. Chlorine dioxide and sodium hypochlorite reduced the microhardness more than other test agents. The highest surface roughness was produced with maleic acid. Chlorine dioxide should be used cautiously during chemomechanical preparation of the root canal system in order to prevent untoward damage to the teeth. PMID:26591249

  12. [Relationship between surface UV radiation and air pollution in Beijing].

    PubMed

    An, Jun-lin; Wang, Yue-si; Li, Xin; Sun, Yang; Shen, Shuang-he

    2008-04-01

    Based on the data of solar radiation and air pollutants collected in Beijing, the relationship between surface ultraviolet (UV) radiation and the content of air pollutants were analyzed, using the radiative transfer model TUV4.4 (Tropospheric Ultraviolet Visible). The results show that average total ozone content is 329 DU and higher in winter and spring, lower in summer and autumn. The inverse relationship exists between ground level UV radiation and total ozone content. This study also shows that a substantial reduction (up to 50%) in the UV radiation on days with high levels of air pollution. Larger fluctuations are found in UV radiation in the summer. The effects of clouds and air pollution on UV are higher than on total solar radiation, and the reduction in UV is about twice as large as the total solar radiation values. Strong reduction in the UV radiation reaching the ground is associated with the increase of tropospheric ozone and nitrogen oxides in Beijing. The correlation coefficient between ozone concentration and decrease in UV radiation is 0.70 in the early afternoon.

  13. Radiation exposure for manned Mars surface missions

    NASA Astrophysics Data System (ADS)

    Simonsen, Lisa C.; Nealy, John E.; Townsend, Lawrence W.; Wilson, John W.

    1990-03-01

    The Langley cosmic ray transport code and the Langley nucleon transport code (BRYNTRN) are used to quantify the transport and attenuation of galactic cosmic rays (GCR) and solar proton flares through the Martian atmosphere. Surface doses are estimated using both a low density and a high density carbon dioxide model of the atmosphere which, in the vertical direction, provides a total of 16 g/sq cm and 22 g/sq cm of protection, respectively. At the Mars surface during the solar minimum cycle, a blood-forming organ (BFO) dose equivalent of 10.5 to 12 rem/yr due to galactic cosmic ray transport and attenuation is calculated. Estimates of the BFO dose equivalents which would have been incurred from the three large solar flare events of August 1972, November 1960, and February 1956 are also calculated at the surface. Results indicate surface BFO dose equivalents of approximately 2 to 5, 5 to 7, and 8 to 10 rem per event, respectively. Doses are also estimated at altitudes up to 12 km above the Martian surface where the atmosphere will provide less total protection.

  14. Radiative transfer modeling of surface chemical deposits

    NASA Astrophysics Data System (ADS)

    Reichardt, Thomas A.; Kulp, Thomas J.

    2016-05-01

    Remote detection of a surface-bound chemical relies on the recognition of a pattern, or "signature," that is distinct from the background. Such signatures are a function of a chemical's fundamental optical properties, but also depend upon its specific morphology. Importantly, the same chemical can exhibit vastly different signatures depending on the size of particles composing the deposit. We present a parameterized model to account for such morphological effects on surface-deposited chemical signatures. This model leverages computational tools developed within the planetary and atmospheric science communities, beginning with T-matrix and ray-tracing approaches for evaluating the scattering and extinction properties of individual particles based on their size and shape, and the complex refractive index of the material itself. These individual-particle properties then serve as input to the Ambartsumian invariant imbedding solution for the reflectance of a particulate surface composed of these particles. The inputs to the model include parameters associated with a functionalized form of the particle size distribution (PSD) as well as parameters associated with the particle packing density and surface roughness. The model is numerically inverted via Sandia's Dakota package, optimizing agreement between modeled and measured reflectance spectra, which we demonstrate on data acquired on five size-selected silica powders over the 4-16 μm wavelength range. Agreements between modeled and measured reflectance spectra are assessed, while the optimized PSDs resulting from the spectral fitting are then compared to PSD data acquired from independent particle size measurements.

  15. Reconstructed structures of nanosized co islands on Ag/Ge(111) mean square root of 3 x mean square root of 3 surfaces.

    PubMed

    Fu, Tsu-Yi; Tsay, Sung-Lin; Lin, Chun-Liang

    2008-02-01

    Structural evolution of Co/Ag/Ge(111) at high temperatures was studied by using scanning tunneling microscopy and low energy electron diffraction. The mean square root of 3 x mean square root of 3-Ag layer between the substrate Ge( 11) and Co adatoms can avoid the formation of Co-Ge compounds below 800 K. The Co atoms nucleate to form islands where mean square root of 13 x mean square root of 13 or 2 x 2 reconstructions were observed after annealing between 373 K and 737 K. The mean square root of 13 x mean square root of 13 structure with mirror symmetry relative to [-211], [11-2], and [1-21] axes was observed for 1-2 layer Co islands. Co islands with over 2 layers appear 2 x 2 structure. All reconstruction structures of the nano-sized Co islands and substrate Ag/Ge(111) mean square root of 3 x mean square root of 3 surface were analyzed using the atomic hard sphere model. The bright protrusions of these reconstructions all sit in the centers of Ag or Ge trimers, which were predicted to have maximum binding energy.

  16. Estimation of Surface Net Radiation from Operational Meteorological Measurements Using Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Geraldo Ferreira, A.; Lopez-Baeza, Ernesto; Soria-Olivas, Emilio; Serrano Lopez, Antonio J.

    2012-07-01

    The study of net radiation at the surface (Rn) is of fundamental importance because this parameter defines the total amount of energy that is available for the physical and biological processes such as air and soil warming and evapotranspiration, the latter being used to optimize the quality and yield of crops, water resources planning, weather forecasting, etc. Despite its importance, the net radiation is measured only in a very few number of standard weather stations. This work presents a methodology based on artificial neural networks (ANN), by modeling the relationships between net radiation and common meteorological variables measured at meteorological stations. The meteorological parameters used as input to the ANN models were: wind velocity and direction, surface and air temperature, relative humidity, and soil moisture and temperature. The output parameter was Rn. A comparison has been made between Rn estimates provided by the neural models and in situ measured Rn values. The statistical results given in terms of low root mean square error and mean absolute error show that the proposed methodology is suitable to estimate net radiation at surface from common meteorological variables.

  17. Combined effects of Lanthanum(III) and elevated Ultraviolet-B radiation on root nitrogen nutrient in soybean seedlings.

    PubMed

    Huang, Guangrong; Wang, Lihong; Sun, Zhaoguo; Li, Xiaodong; Zhou, Qing; Huang, Xiaohua

    2015-02-01

    Rare earth element pollution and elevated ultraviolet-B (UV-B) radiation occur simultaneously in some regions, but the combined effects of these two factors on plants have not attracted enough attention. Nitrogen nutrient is vital to plant growth. In this study, the combined effects of lanthanum(III) and elevated UV-B radiation on nitrate reduction and ammonia assimilation in soybean (Glycine max L.) roots were investigated. Treatment with 0.08 mmol L(-1) La(III) did not change the effects of elevated UV-B radiation on nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (GOGAT), glutamate dehydrogenase (GDH), nitrate, ammonium, amino acids, or soluble protein in the roots. Treatment with 0.24 mmol L(-1) La(III) and elevated UV-B radiation synergistically decreased the NR, NiR, GS, and GOGAT activities as well as the nitrate, amino acid, and soluble protein levels, except for the GDH activity and ammonium content. Combined treatment with 1.20 mmol L(-1) La(III) and elevated UV-B radiation produced severely deleterious effects on all test indices, and these effects were stronger than those induced by La(III) or elevated UV-B radiation treatment alone. Following the withdrawal of La(III) and elevated UV-B radiation, all test indices for the combined treatments with 0.08/0.24 mmol L(-1) La(III) and elevated UV-B radiation recovered to a certain extent, but they could not recover for treatments with 1.20 mmol L(-1) La(III) and elevated UV-B radiation. In summary, combined treatment with La(III) and elevated UV-B radiation seriously affected nitrogen nutrition in soybean roots through the inhibition of nitrate reduction and ammonia assimilation.

  18. Effect of nickel titanium file design on the root surface strain and apical microcracks.

    PubMed

    Jamleh, Ahmed; Adorno, Carlos G; Ebihara, Arata; Suda, Hideaki

    2016-04-01

    The aim of this study was to determine the effect of nickel titanium file design on the root surface strain generated and apical microcracks caused during canal shaping. Thirty-three mandibular incisors were distributed into LightSpeed X, FlexMaster and a control group. A strain gauge was fixed apically on the proximal root surface to determine the maximum strain during canal shaping. Except for the control group, all root canals were enlarged to size 50. Images were taken after removing the apical 1 and 2 mm of the root end. Mean maximum strain values and presence of microcracks were statistically compared using the t-test and chi-square test, respectively. During canal shaping, the strain increased cumulatively with mean maximum strains of 808.2 ± 228.8 and 525.1 ± 168.9 microstrain in LightSpeed X and FlexMaster, respectively (P = 0.004). Both systems caused comparable microcracks. Although LightSpeed X produced higher maximum strain, no difference in microcrack development was found between both systems.

  19. Subcellular distribution of uranium in the roots of Spirodela punctata and surface interactions

    NASA Astrophysics Data System (ADS)

    Nie, Xiaoqin; Dong, Faqin; Liu, Ning; Liu, Mingxue; Zhang, Dong; Kang, Wu; Sun, Shiyong; Zhang, Wei; Yang, Jie

    2015-08-01

    The subcellular distribution of uranium in roots of Spirodela punctata (duckweed) and the process of surface interaction were studied upon exposure to U (0, 5-200 mg/L) at pH 5. The concentration of uranium in each subcelluar fraction increased significantly with increasing solution U level, after 200 mg/L uranium solution treatment 120 h, the proportion of uranium concentration approximate as 8:2:1 in the cell wall organelle and cytosol fractions of roots of S. punctata. OM SEM and EDS showed after 5-200 mg/L U treatment 4-24 h, some intracellular fluid released from the root cells, after 100 mg/L U treatment 48 h, the particles including 35% Fe (wt%) and other organic matters such as EPS released from the cells, most of the uranium bound onto the root surface and contacted with phosphorus ligands and formed as nano-scales U-P lamellar crystal, similar crystal has been found in the cell wall and organelle fractions after 50 mg/L U treatment 120 h. FTIR and XPS analyses result indicates the uranium changed the band position and shapes of phosphate group, and the region of characteristic peak belongs to U(VI) and U(IV) were also observed.

  20. Mechanical touch responses of Arabidopsis TCH1-3 mutant roots on inclined hard-agar surface

    NASA Astrophysics Data System (ADS)

    Zha, Guodong; Wang, Bochu; Liu, Junyu; Yan, Jie; Zhu, Liqing; Yang, Xingyan

    2016-01-01

    The gravity-induced mechanical touch stimulus can affect plant root architecture. Mechanical touch responses of plant roots are an important aspect of plant root growth and development. Previous studies have reported that Arabidopsis TCH1-3 genes are involved in mechano-related events, how-ever, the physiological functions of TCH1-3 genes in Arabidopsis root mechanoresponses remain unclear. In the present study, we applied an inclined hard agar plate method to produce mechanical touch stimulus, and provided evidence that altered mechanical environment could influence root growth. Furthermore, tch1-3 Arabidopsis mutants were investigated on inclined agar surfaces to explore the functions of TCH1-3 genes on Arabidopsis root mechanoresponses. The results showed that two tch2 mutants, cml24-2 and cml24-4, exhibited significantly reduced root length, biased skewing, and decreased density of lateral root. In addition, primary root length and density of lateral root of tch3 (cml12-2) was significantly decreased on inclined agar surfaces. This study indicates that the tch2 and tch3 mutants are hypersensitive to mechanical touch stimulus, and TCH2 (CML24-2 and CML24-4) and TCH3 (CML12-2) genes may participate in the mechanical touch response of Arabidopsis roots.

  1. The radiation of surface wave energy: Implications for volcanic tremor

    NASA Astrophysics Data System (ADS)

    Haney, M. M.; Denolle, M.; Lyons, J. J.; Nakahara, H.

    2015-12-01

    The seismic energy radiated by active volcanism is one common measurement of eruption size. For example, the magnitudes of individual earthquakes in volcano-tectonic (VT) swarms can be summed and expressed in terms of cumulative magnitude, energy, or moment release. However, discrepancies exist in current practice when treating the radiated energy of volcano seismicity dominated by surface waves. This has implications for volcanic tremor, since eruption tremor typically originates at shallow depth and is made up of surface waves. In the absence of a method to compute surface wave energy, estimates of eruption energy partitioning between acoustic and seismic waves typically assume seismic energy is composed of body waves. Furthermore, without the proper treatment of surface wave energy, it is unclear how much volcanic tremor contributes to the overall seismic energy budget during volcanic unrest. To address this issue, we derive, from first principles, the expression of surface wave radiated energy. In contrast with body waves, the surface wave energy equation is naturally expressed in the frequency domain instead of the time domain. We validate our result by reproducing an analytical solution for the radiated power of a vertical force source acting on a free surface. We further show that the surface wave energy equation leads to an explicit relationship between energy and the imaginary part of the surface wave Green's tensor at the source location, a fundamental property recognized within the field of seismic interferometry. With the new surface wave energy equation, we make clear connections to reduced displacement and propose an improved formula for the calculation of surface wave reduced displacement involving integration over the frequency band of tremor. As an alternative to reduced displacement, we show that reduced particle velocity squared is also a valid physical measure of tremor size, one based on seismic energy rate instead of seismic moment rate. These

  2. 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.

  3. Strong emission of terahertz radiation from nanostructured Ge surfaces

    SciTech Connect

    Kang, Chul; Maeng, Inhee; Kee, Chul-Sik; Leem, Jung Woo; Yu, Jae Su; Kim, Tae Heon; Lee, Jong Seok

    2015-06-29

    Indirect band gap semiconductors are not efficient emitters of terahertz radiation. Here, we report strong emission of terahertz radiation from germanium wafers with nanostructured surfaces. The amplitude of THz radiation from an array of nano-bullets (nano-cones) is more than five (three) times larger than that from a bare-Ge wafer. The power of the terahertz radiation from a Ge wafer with an array of nano-bullets is comparable to that from n-GaAs wafers, which have been widely used as a terahertz source. We find that the THz radiation from Ge wafers with the nano-bullets is even more powerful than that from n-GaAs for frequencies below 0.6 THz. Our results suggest that introducing properly designed nanostructures on indirect band gap semiconductor wafers is a simple and cheap method to improve the terahertz emission efficiency of the wafers significantly.

  4. Strain Distribution in Root Surface Dentin of Maxillary Central Incisors during Lateral Compaction

    PubMed Central

    Pilo, Raphael; Metzger, Zvi; Brosh, Tamar

    2016-01-01

    Aim To precisely quantify the circumferential strains created along the radicular dentin of maxillary incisors during a simulated clinical procedure of lateral compaction. Methods Six miniature strain gauges were bonded on the roots of fourteen recently extracted maxillary central incisors that were subjected to root canal instrumentation. The strain gauges were bonded at three levels (apical, middle, and coronal) and four aspects (buccal, lingual, mesial, and distal) of the roots. Each tooth was embedded in a PVC cylinder containing polyvinyl-siloxane impression material. Root filling was then performed by simulating the clinical procedure of lateral compaction using nickel-titanium finger spreaders. The force applied to the spreader and the strains developing in the surface root dentin were continuously recorded at a frequency of 10 Hz. Results The highest strains that developed during lateral compaction were in the mesial and distal aspects at the apical level of the root. The magnitudes of the maximal mesial/distal strains at the apical as well as the mid-root levels were approximately 2.5–3 times higher than those at the buccal/lingual aspects (p = 0.041). The strains decreased significantly (p<0.04) from the apical through the mid-root levels to the coronal level, yielding gradients of 2.5- and 6-fold, respectively. The mesial and distal strains were consistently tensile and did not differ significantly; however, the buccal strains were generally 35–65% higher than the lingual strains (p = 0.078). Lateral compaction resulted in the gradual build-up of residual strains, resulting in generation of a 'stair-step' curve. These strains declined gradually and almost completely disappeared after 1000 sec. Conclusions With proper mounting of several miniature strain gauges at various levels and aspects of the root, significant circumferential strains can be monitored under clinically relevant compaction forces. The residual strains at the end of lateral

  5. A Study of Surface Temperatures, Clouds and Net Radiation

    NASA Technical Reports Server (NTRS)

    Dhuria, Harbans

    1996-01-01

    This study focused on the seasonal relationships and interactions of climate parameters such as the surface temperatures, net radiation, long wave flux, short wave flux, and clouds on a global basis. Five years of observations (December 1984 to November 1989) from the Earth Radiation Budget Experiment (ERBE) and the International Satellite Cloud Climatology Program (ISCCP) were used to study both seasonal variations and interannual variations by use of a basic radiation budget equation. In addition, the study was extended to include an analysis of the cloud forcing due El-Nino's impact on the ERBE parameters.

  6. Tunable directive radiation of surface-plasmon diffraction gratings.

    PubMed

    Lee, Youngkyu; Hoshino, Kazunori; Alù, Andrea; Zhang, Xiaojing

    2013-02-11

    We experimentally demonstrate tunable radiation from a periodic array of plasmonic nanoscatterers, tailored to convert surface plasmon polaritons into directive leaky modes. Extending our previous studies on efficient directional beaming based on leaky-wave radiation from periodic gratings driven by a subwavelength slit, we experimentally show dynamic beam sweeping by tuning the directional leaky-wave mechanism in real-time. Two alternative tuning mechanisms, wavelength- and index-mediated beam sweeping, are employed to modify the relative phase of scattered light at each grating edge and provide the required modification of the radiation angle.

  7. Space radiation dose estimates on the surface of Mars.

    PubMed

    Simonsen, L C; Nealy, J E; Townsend, L W; Wilson, J W

    1990-01-01

    A future goal of the U.S. space program is a commitment to the manned exploration and habitation of Mars. An important consideration of such missions is the exposure of crew members to the damaging effects of ionizing radiation from high-energy galactic cosmic ray fluxes and solar proton flares. The crew will encounter the most harmful radiation environment in transit to Mars from which they must be adequately protected. However, once on the planet's surface, the Martian environment should provide a significant amount of protection from free-space radiative fluxes. In current Mars scenario descriptions, the crew flight time to Mars is estimated to be anywhere from 7 months to over a year each way, with stay times on the surface ranging from 20 days to 2 years. To maintain dose levels below established astronaut limits, dose estimates need to be determined for the entire mission length. With extended crew durations on the surface anticipated, the characterization of the Mars radiation environment is important in assessing all radiation protection requirements. This synopsis focuses on the probable doses incurred by surface inhabitants from the transport of galactic cosmic rays and solar protons through the Mars atmosphere. PMID:11537609

  8. 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

  9. Effect of energy (J) on temperature changes at apical root surface when using Er:YAG laser to enlarge root canals

    NASA Astrophysics Data System (ADS)

    Pecora, Jesus D.; Brugnera, Aldo, Jr.; Zanin, Fatima A. A.; Marchesan, Melissa A.; Daghastanli, Naser A.; Silva, Reginaldo S.

    2000-03-01

    The use of lasers for cleaning, shaping and disinfecting root canals must not produce heat which damages periapical tissue and alveolar bone. The aim of the present study was to determine the increase of external temperature at the apical surface of the root canal after Er:YAG laser irradiation with a 250 micrometer diameter fiberoptic guide with and without distilled and deionized water at 3 different total energies. Thirty single-rooted teeth were instrumented to #25 K-file using distilled and deionized water for irrigation. They were divided into three groups according to total energy (15J, 30J and 45J with 15 Hz and 140 mJ per pulse). Each group was irradiated with water and then without water. The increase in temperature at the apical root surface was measured with a multimeter and a thermocouple. Changes in apical temperature were significantly different in all groups (p less than 0.01; 15 J less than 45 J less than 30 J). Less time was necessary for return to initial room temperature at 15 J. We conclude that in vitro use of the Er:YAG laser (total energy of 15, 30, and 45 J) increased external apical root temperature and that the root canal must be filled with distilled and deionized water to reduce the risk of an increase in temperature.

  10. First global WCRP shortwave surface radiation budget dataset

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Charlock, T. P.; Staylor, W. F.; Pinker, R. T.; Laszlo, I.; Ohmura, A.; Gilgen, H.; Konzelman, T.; DiPasquale, R. C.; Moats, C. D.

    1995-01-01

    Shortwave radiative fluxes that reach the Earth's surface are key factors that influence atmospheric and oceanic circulations as well as surface climate. Yet, information on these fluxes is meager. Surface site data are generally available from only a limited number of observing stations over land. Much less is known about the large-scale variability of the shortwave radiative fluxes over the oceans, which cover most of the globe. Recognizing the need to produce global-scale fields of such fluxes for use in climate research, the World Climate Research Program has initiated activities that led to the establishment of the Surface Radiation Budget Climatology Project with the ultimate goal to determine various components of the surface radiation budget from satellite data. In this paper, the first global products that resulted from this activity are described. Monthly and daily data on a 280-km grid scale are available. Samples of climate parameters obtainable from the dataset are presented. Emphasis is given to validation and limitations of the results. For most of the globe, satellite estimates have bias values between +/- 20 W/sq m and rms values are around 25 W/sq m. There are specific regions with much larger uncertainties however.

  11. Exposure to 915 MHz radiation induces micronuclei in Vicia faba root tips.

    PubMed

    Gustavino, Bianca; Carboni, Giovanni; Petrillo, Roberto; Paoluzzi, Giovanni; Santovetti, Emanuele; Rizzoni, Marco

    2016-03-01

    The increasing use of mobile phones and wireless networks raised a great debate about the real carcinogenic potential of radiofrequency-electromagnetic field (RF-EMF) exposure associated with these devices. Conflicting results are reported by the great majority of in vivo and in vitro studies on the capability of RF-EMF exposure to induce DNA damage and mutations in mammalian systems. Aimed at understanding whether less ambiguous responses to RF-EMF exposure might be evidenced in plant systems with respect to mammalian ones, in the present work the mutagenic effect of RF-EMF has been studied through the micronucleus (MN) test in secondary roots of Vicia faba seedlings exposed to mobile phone transmission in controlled conditions, inside a transverse electro magnetic (TEM) cell. Exposure of roots was carried out for 72h using a continuous wave (CW) of 915 MHz radiation at three values of equivalent plane wave power densities (23, 35 and 46W/m(2)). The specific absorption rate (SAR) was measured with a calorimetric method and the corresponding values were found to fall in the range of 0.4-1.5W/kg. Results of three independent experiments show the induction of a significant increase of MN frequency after exposure, ranging from a 2.3-fold increase above the sham value, at the lowest SAR level, up to a 7-fold increase at the highest SAR. These findings are in agreement with the limited number of data on cytogenetic effects detected in other plant systems exposed to mobile phone RF-EMF frequencies and clearly show the capability of radiofrequency exposure to induce DNA damage in this eukaryotic cell system.

  12. Exposure to 915 MHz radiation induces micronuclei in Vicia faba root tips.

    PubMed

    Gustavino, Bianca; Carboni, Giovanni; Petrillo, Roberto; Paoluzzi, Giovanni; Santovetti, Emanuele; Rizzoni, Marco

    2016-03-01

    The increasing use of mobile phones and wireless networks raised a great debate about the real carcinogenic potential of radiofrequency-electromagnetic field (RF-EMF) exposure associated with these devices. Conflicting results are reported by the great majority of in vivo and in vitro studies on the capability of RF-EMF exposure to induce DNA damage and mutations in mammalian systems. Aimed at understanding whether less ambiguous responses to RF-EMF exposure might be evidenced in plant systems with respect to mammalian ones, in the present work the mutagenic effect of RF-EMF has been studied through the micronucleus (MN) test in secondary roots of Vicia faba seedlings exposed to mobile phone transmission in controlled conditions, inside a transverse electro magnetic (TEM) cell. Exposure of roots was carried out for 72h using a continuous wave (CW) of 915 MHz radiation at three values of equivalent plane wave power densities (23, 35 and 46W/m(2)). The specific absorption rate (SAR) was measured with a calorimetric method and the corresponding values were found to fall in the range of 0.4-1.5W/kg. Results of three independent experiments show the induction of a significant increase of MN frequency after exposure, ranging from a 2.3-fold increase above the sham value, at the lowest SAR level, up to a 7-fold increase at the highest SAR. These findings are in agreement with the limited number of data on cytogenetic effects detected in other plant systems exposed to mobile phone RF-EMF frequencies and clearly show the capability of radiofrequency exposure to induce DNA damage in this eukaryotic cell system. PMID:26476436

  13. Effect of Mulch Surface Color on Root-knot of Tomato Grown in Simulated Planting Beds

    PubMed Central

    Fortnum, B. A.; Kasperbauer, M. J.; Decoteau, D. R.

    2000-01-01

    The effect of different-colored polyethylene mulches on quantity and spectra of reflected light, plant morphology, and root-knot disease was studied in tomato (Lycopersicon esculentum) grown in simulated planting beds. Tomato plants were inoculated with Meloidogyne incognita at initial populations (Pi) of 0, 1,000, 10,000, or 50,000 eggs/plant, and grown in a greenhouse for 50 days over white, red, or black mulch. Soil temperature was kept constant among the mulch treatments by placing an insulation barrier between the colored mulch and the soil surface. Soil temperature varied less than 0.5 °C between soil chambers at solar noon. Tomatoes grown over white mulch received more reflected photosynthetic light and had greater shoot weights (27%), root weights (32%), and leaf area (20%) than plants grown over black mulch. Plants grown over red mulch received a higher far-red-to-red ratio in the reflected light. Mulch color altered the plant's response to root-knot nematode infection by changing the distribution of mass in axillary shoots. At high Pi, axillary leaf area and leaf weight were greater in tomato grown over white mulch than when grown over red mulch. The root-gall index was lower for plants grown over white mulch than similar plants grown over red mulch. PMID:19270954

  14. Surface plasmon amplification by stimulated emission of radiation (SPASER)

    DOEpatents

    Stockman, Mark I.; Bergman, David J.

    2009-08-04

    A nanostructure is used to generate a highly localized nanoscale optical field. The field is excited using surface plasmon amplification by stimulated emission of radiation (SPASER). The SPASER radiation consists of surface plasmons that undergo stimulated emission, but in contrast to photons can be localized within a nanoscale region. A SPASER can incorporate an active medium formed by two-level emitters, excited by an energy source, such as an optical, electrical, or chemical energy source. The active medium may be quantum dots, which transfer excitation energy by radiationless transitions to a resonant nanosystem that can play the same role as a laser cavity in a conventional laser. The transitions are stimulated by the surface plasmons in the nanostructure, causing the buildup of a macroscopic number of surface plasmons in a single mode.

  15. ENSO surface longwave radiation forcing over the tropical Pacific

    NASA Astrophysics Data System (ADS)

    Pavlakis, K. G.; Hatzidimitriou, D.; Drakakis, E.; Matsoukas, C.; Fotiadi, A.; Hatzianastassiou, N.; Vardavas, I.

    2006-12-01

    We have studied the spatial and temporal variation of the surface longwave radiation (downwelling and net) over a 21-year period in the tropical and subtropical Pacific Ocean (40 S-40 N, 90 E-75 W). The fluxes were computed using a deterministic model for atmospheric radiation transfer, along with satellite data from the ISCCP-D2 database and reanalysis data from NCEP/NCAR (acronyms explained in main text), for the key atmospheric and surface input parameters. An excellent correlation was found between the downwelling longwave radiation (DLR) anomaly and the Niño-3.4 index time-series, over the Niño-3.4 region located in the central Pacific. A high anti-correlation was also found over the western Pacific (15-0 S, 105-130 E). There is convincing evidence that the time series of the mean downwelling longwave radiation anomaly in the western Pacific precedes that in the Niño-3.4 region by 3-4 months. Thus, the downwelling longwave radiation anomaly is a complementary index to the SST anomaly for the study of ENSO events and can be used to asses whether or not El Niño or La Niña conditions prevail. Over the Niño-3.4 region, the mean DLR anomaly values range from +20 Wm-2 during El Niño episodes to -20 Wm-2 during La Niña events, while over the western Pacific (15-0 S, 105-130 E) these values range from -15 Wm-2 to +10 Wm-2, respectively. The long- term average (1984-2004) distribution of the net surface longwave radiation to the surface over the tropical and subtropical Pacific for the three month period November-December-January shows a net thermal cooling of the ocean surface. When El Niño conditions prevail, the thermal radiative cooling in the central and south-eastern tropical Pacific becomes weaker by 10 Wm-2 south of the equator in the central Pacific (7-0 S, 160-120 W) for the three-month period of NDJ, because the DLR increase is larger than the increase in surface thermal emission. In contrast

  16. Shortwave spectral radiative forcing of cumulus clouds from surface observations

    NASA Astrophysics Data System (ADS)

    Kassianov, E.; Barnard, J.; Berg, L. K.; Long, C. N.; Flynn, C.

    2011-04-01

    The spectral changes of the shortwave total, direct and diffuse cloud radiative forcing (CRF) at surface are examined for the first time using spectrally resolved all-sky flux observations and clear-sky fluxes. The latter are computed applying a physically based approach, which accounts for the spectral changes of aerosol optical properties and surface albedo. Application of this approach to 13 summertime days with single-layer continental cumuli demonstrates: (i) the substantial contribution of the diffuse component to the total CRF, (ii) the well-defined spectral variations of total CRF in the visible spectral region, and (iii) the strong statistical relationship between spectral (500 nm) and shortwave broadband values of total CRF. Our results suggest that the framework based on the visible narrowband fluxes can provide important radiative quantities for rigorous evaluation of radiative transfer parameterizations and also can be applied for estimation of the shortwave broadband CRF.

  17. Assessment of non-carious root surface defects in areas of gingival recession: A descriptive study

    PubMed Central

    Jacob, Caroline-Annette; Nainar, Deepavalli-Arumuga

    2016-01-01

    Background The purpose of this descriptive study was to observe the distribution of four different classes of non-carious cervical root surface discrepancies in teeth with gingival recession. Additionally to explore the different treatment modalities in the literature for each of these defects. Material and Methods A total of 150 subjects with at least one labial gingival recession were included in the study. 1400 teeth were evaluated using 2.5 X magnification loupes and UNC -15 probe for the presence of the cemento-enamel junction and step like defects according to Pini-Prato’s classification: A-, identifiable CEJ without defect; A+, identifiable CEJ with defect; B-, unidentifiable CEJ without defect, B+, unidentifiable CEJ with defect. Further a comprehensive electronic and hand search of pubmed indexed journals was performed to identify appropriate treatment modalities for these defects and their predictability following restorative/surgical or combination of both. Results A total of 1400 teeth with exposed root surfaces were examined (793 Maxillary; 607 mandibular). 499 teeth were A-, 405 were A+, 322 were B+ and 174 were B-. The distribution of these defects in different teeth was: 36% premolars, 32% molars, 21% incisors and 11% canines, collectively 68% in the aesthetic zone. Conclusions Majority of these lesions are in the maxillary aesthetic zone. Hence the presence of the CEJ and the defect must be taken into account while managing these defects surgically. Key words:Cervical abrasion, gingival recession, magnification loupes, root coverage, step defects. PMID:27703607

  18. Evaluation of surface energy and radiation balance systems for FIFE

    NASA Technical Reports Server (NTRS)

    Fritschen, Leo J.; Qian, Ping

    1988-01-01

    The energy balance and radiation balance components were determined at six sites during the First International Satellite Land Surface Climatology Project Field Experiment (FIFE) conducted south of Manhattan, Kansas during the summer of 1987. The objectives were: to determine the effect of slope and aspect, throughout a growing season, on the magnitude of the surface energy balance fluxes as determined by the Energy Balance Method (EBM); to investigate the calculation of the soil heat flux density at the surface as calculated from the heat capacity and the thermal conductivity equations; and to evaluate the performance of the Surface Energy and Radiation Balance System (SERBS). A total of 17 variables were monitored at each site. They included net, solar (up and down), total hemispherical (up and down), and diffuse radiation, soil temperature and heat flux density, air and wet bulb temperature gradients, wind speed and direction, and precipitation. A preliminary analysis of the data, for the season, indicate that variables including net radiation, air temperature, vapor pressure, and wind speed were quite similar at the sites even though the sites were as much as 16 km apart and represented four cardinal slopes and the top of a ridge.

  19. Morphological Changes Of The Root Surface And Fracture Resistance After Treatment Of Root Fracture By CO2 Laser And Glass Ionomer Or Mineral Trioxide Aggregates

    NASA Astrophysics Data System (ADS)

    Badr, Y. A.; Abd El-Gawad, L. M.; Ghaith, M. E.

    2009-09-01

    This in vitro study evaluates the morphological changes of the root surface and fracture resistance after treatment of root cracks by CO2 laser and glass Ionomer or mineral trioxide aggregates (MTA). Fifty freshly extracted human maxillary central incisor teeth with similar dimension were selected. Crowns were sectioned at the cemento-enamel junction, and the lengths of the roots were adjusted to 13 mm. A longitudinal groove with a dimension of 1×5 mm2 and a depth of 1.5 mm was prepared by a high speed fissure bur on the labial surface of the root. The roots were divided into 5 groups: the 10 root grooves in group 1 were remained unfilled and were used as a control group. The 10 root grooves in group 2 were filled with glass Ionomer, 10 root grooves in group 3 were filled with MTA, the 10 root grooves in group 4 were filled with glass Ionomer and irradiated by CO2 laser and the 10 root grooves in group 5 were filled with MTA and irradiated with CO2 laser. Scanning electron microscopy was performed for two samples in each group. Tests for fracture strength were performed using a universal testing machine and a round tip of a diameter of 4 mm. The force was applied vertically with a constant speed of 1 mm min 1. For each root, the force at the time of fracture was recorded in Newtons. Results were evaluated statistically with ANOVA and Turkey's Honestly Significant Difference (HSD) tests. SEM micrographs revealed that the melted masses and the plate-like crystals formed a tight Chemical bond between the cementum and glass Ionomer and melted masses and globular like structure between cementum and MTA. The mean fracture resistance was the maximum fracture resistance in group 5 (810.8 N). Glass Ionomer and MTA with the help of CO2 laser can be an alternative to the treatment of tooth crack or fracture. CO2 laser increase the resistance of the teeth to fracture.

  20. Basipetal propagation of gravity-induced surface pH changes along primary roots of Lepidium sativum L.

    PubMed

    Monshausen, Gabriele B; Sievers, Andreas

    2002-10-01

    While there is ample evidence for a role of auxin in root gravitropism, the seeming rapidity of gravi-induced changes in electrical parameters has so far been an argument against auxin being a primary signal in gravitropic signal transmission. To address this problem, we re-investigated the effect of gravistimulation on membrane voltages of Lepidium sativum L. and Vigna mungo L. root cells. In our hands, gravistimulation did not induce changes in membrane voltage in cells of the root cap statenchyma, root meristem or apical elongation zone that can be correlated with the orientation of the cells relative to the gravity vector. While these results challenge a model of rapid electrically based signal transmission, there is evidence for a slower signal propagation along gravistimulated L. sativum roots. Using multiple proton-selective microelectrodes to simultaneously measure surface pH on opposite root flanks at different distances from the root tip, we observed gravi-induced asymmetric pH changes at the surface of all investigated root zones. Upon gravistimulation, the surface pH decreased on the physically upper root flank and increased on the lower flank. The pH asymmetry appeared first [2.1+/-0.4 min (mean +/- SD) after tilting] at the root cap and then - with incrementing lag times - at the meristem (after 2.5+/-0.3 min at 300 micro m from root tip; after 3.7+/-0.4 min at 700 micro m) and apical elongation zone (4.8+/-0.5 min at 1,000 micro m), suggesting a basipetal progression of differential surface acidification at a rate of 250-350 micro m min(-1), consistent with reported auxin transport rates.

  1. The NOAA Integrated Surface Irradiance Study (ISIS) - A new surface radiation monitoring program

    SciTech Connect

    Hicks, B.B.; DeLuisi, J.J.

    1996-12-01

    This paper describes a new radiation monitoring program, the Integrated Surface Irradiance Study (ISIS), that builds upon and takes over from earlier NOAA networks monitoring components of solar radiation [both the visible component (SOLRAD) and the shortwave component that causes sunburn, UV-B] across the continental United States. ISIS is implemented in two levels. Level 1 addresses incoming radiation only, and level 2 addresses the surface radiation balance. Level 2 also constitutes the SURFRAD (Surface Radiation) program of the NOAA Office of Global Programs, specifically intended to provide radiation data to support large-scale hydrologic studies that will be conducted under the Global Energy and Water Cycle Experiment. Eventually, it is planned for level 2 sites to monitor all components of the surface energy balance. Both levels of ISIS will eventually measure both visible and UV radiation components. At present, there are nine sites that are considered to be at ISIS level 1 standard and an additional four level 2 SURFRAD sites. A 10th level 1 site will be in operation soon. Plans call for an increase in the number of sites of both kinds, up to about 15 ISIS sites, of which 6 will be at the SURFRAD level. 20 refs., 2 figs., 1 tab.

  2. ENSO surface longwave radiation forcing over the tropical Pacific

    NASA Astrophysics Data System (ADS)

    Pavlakis, K. G.; Hatzidimitriou, D.; Drakakis, E.; Matsoukas, C.; Fotiadi, A.; Hatzianastassiou, N.; Vardavas, I.

    2007-04-01

    We have studied the spatial and temporal variation of the surface longwave radiation (downwelling and net) over a 21-year period in the tropical and subtropical Pacific Ocean (40 S-40 N, 90 E-75 W). The fluxes were computed using a deterministic model for atmospheric radiation transfer, along with satellite data from the ISCCP-D2 database and reanalysis data from NCEP/NCAR (acronyms explained in main text), for the key atmospheric and surface input parameters. An excellent correlation was found between the downwelling longwave radiation (DLR) anomaly and the Niño-3.4 index time-series, over the Niño-3.4 region located in the central Pacific. A high anti-correlation was also found over the western Pacific (15-0 S, 105-130 E). There is convincing evidence that the time series of the mean downwelling longwave radiation anomaly in the western Pacific precedes that in the Niño-3.4 region by 3-4 months. Thus, the downwelling longwave radiation anomaly is a complementary index to the SST anomaly for the study of ENSO events and can be used to asses whether or not El Niño or La Niña conditions prevail. Over the Niño-3.4 region, the mean DLR anomaly values range from +20 Wm-2 during El Niño episodes to -20 Wm-2 during La Niña events, while over the western Pacific (15-0 S, 105-130 E) these values range from -15 Wm-2 to +10 Wm-2, respectively. The long- term average (1984-2004) distribution of the net downwelling longwave radiation at the surface over the tropical and subtropical Pacific for the three month period November-December-January shows a net thermal cooling of the ocean surface. When El Niño conditions prevail, the thermal radiative cooling in the central and south-eastern tropical Pacific becomes weaker by 10 Wm-2 south of the equator in the central Pacific (7-0 S, 160-120 W) for the three-month period of NDJ, because the DLR increase is larger than the increase in surface thermal emission. In contrast

  3. Predicting root zone soil moisture with satellite near-surface moisture data in semiarid environments

    NASA Astrophysics Data System (ADS)

    Manfreda, S.; Baldwin, D. C.; Keller, K.; Smithwick, E. A. H.; Caylor, K. K.

    2015-12-01

    One of the most critical variables in semiarid environment is the soil water content that represents a controlling factor for both ecological and hydrological processes. Soil moisture monitoring over large scales may be extremely useful, but it is limited by the fact that most of the available tools provides only surface measurements not representative of the effective amount of water stored in the subsurface. Therefore, a methodology able to infer root-zone soil moisture starting from surface measurements is highly desirable. Recently a new simplified formulation has been introduced to provide a formal description of the mathematical relationship between surface measurements and root-zone soil moisture (Manfreda et al., HESS 2014). This is a physically based approach derived from the soil water balance equation, where different soil water loss functions have been explored in order to take into account for the non-linear processes governing soil water fluxes. The study highlighted that the soil loss function is the key for such relationship that is therefore strongly influenced by soil type and physiological plant types. The new formulation has been tested on soil moisture based on measurements taken from the African Monsoon Multidisciplinary Analysis (AMMA) and the Soil Climate Analysis Network (SCAN) databases. The method sheds lights on the physical controls for soil moisture dynamics and on the possibility to use such a simplified method for the description of root-zone soil moisture. Furthermore, the method has been also couple with an Enasamble Kalman Filter (EnKF) in order to optimize its performances for the large scale monitoring based the new satellite near-surface moisture data (SMAP). The optimized SMAR-EnKF model does well in both wet and dry climates and across many different soil types (51 SCAN locations) providing a strategy for real-time soil moisture monitoring.

  4. Surface Solar Radiation in North America: Observations, Reanalyses, Satellite and Derived Products

    NASA Astrophysics Data System (ADS)

    Slater, A. G.

    2015-12-01

    Observations of daily surface solar/shortwave radiation data from over 4000 stations have been gathered, covering much of the lower 48 continental states of the US as well as portions of Alberta and British Columbia, Canada. The quantity of data increases almost linearly from 1998 when only several hundred stations had data. A quality control procedure utilizing threshold values along with computing the clear sky radiation envelope for individual stations was implemented to both screen bad data and rescue informative data. Over two thirds of the observations are seen as acceptable. Fifteen different surface solar radiation products are assessed relative to observations, including reanalyses (20thC, CFSRR, ERAI, JRA-55, MERRA, NARR, NCEP), derived products (CRU_NCEP, DAYMET, GLDAS, GSWP3, MsTMIP, NLDAS) and two satellite products (CERES and GOES). All except the CERES product are daily or finer in temporal resolution. The root mean square error of spatial biases is greater than 18Wm-2 for 13 of the 15 products over the summer season (June, July, August). None of the daily resolution products fulfill all three desirable criteria of low (<5%) annual or seasonal bias, high correlation with observed cloudiness and correct distribution of clear sky radiation. Some products display vestiges of underlying algorithm issues (e.g. from MTCLIM ver4.3) or bias correction methods. A new bias correction method is introduced that preserves clear sky radiation values and better replicates cloudiness statistics. The current quantity of data over the continental US suggests a solar radiation product based on, or enhanced with, observations is feasible.

  5. Ultraviolet Radiation-induced Alteration of Martian Surface Materials

    NASA Technical Reports Server (NTRS)

    Yen, A. S.

    1999-01-01

    The nature and origin of martian surface materials cannot be fully characterized without addressing the unusual reactivity of the soil and the effects of exposure to the unique martian environment. Our laboratory experiments show that ultraviolet radiation at the martian surface can result in the oxidation of metal atoms and the creation of reactive oxygen species on grain surfaces. This process is important in understanding the nature and evolution of martian soils. It can explain the reactivity discovered by the Viking Landers and possibly the origin of the ferric component of the soil.

  6. Changes in biologically active ultraviolet radiation reaching the Earth's surface.

    PubMed

    Madronich, S; McKenzie, R L; Björn, L O; Caldwell, M M

    1998-10-01

    Stratospheric ozone levels are near their lowest point since measurements began, so current ultraviolet-B (UV-B) radiation levels are thought to be close to their maximum. Total stratospheric content of ozone-depleting substances is expected to reach a maximum before the year 2000. All other things being equal, the current ozone losses and related UV-B increases should be close to their maximum. Increases in surface erythemal (sunburning) UV radiation relative to the values in the 1970s are estimated to be: about 7% at Northern Hemisphere mid-latitudes in winter/spring; about 4% at Northern Hemisphere mid-latitudes in summer/fall; about 6% at Southern Hemisphere mid-latitudes on a year-round basis; about 130% in the Antarctic in spring; and about 22% in the Arctic in spring. Reductions in atmospheric ozone are expected to result in higher amounts of UV-B radiation reaching the Earth's surface. The expected correlation between increases in surface UV-B radiation and decreases in overhead ozone has been further demonstrated and quantified by ground-based instruments under a wide range of conditions. Improved measurements of UV-B radiation are now providing better geographical and temporal coverage. Surface UV-B radiation levels are highly variable because of cloud cover, and also because of local effects including pollutants and surface reflections. These factors usually decrease atmospheric transmission and therefore the surface irradiances at UV-B as well as other wavelengths. Occasional cloud-induced increases have also been reported. With a few exceptions, the direct detection of UV-B trends at low- and mid-latitudes remains problematic due to this high natural variability, the relatively small ozone changes, and the practical difficulties of maintaining long-term stability in networks of UV-measuring instruments. Few reliable UV-B radiation measurements are available from pre-ozone-depletion days. Satellite-based observations of atmospheric ozone and clouds are

  7. Numerical simulation of the radiation environment on Martian surface

    NASA Astrophysics Data System (ADS)

    Zhao, L.

    2015-12-01

    The radiation environment on the Martian surface is significantly different from that on earth. Existing observation and studies reveal that the radiation environment on the Martian surface is highly variable regarding to both short- and long-term time scales. For example, its dose rate presents diurnal and seasonal variations associated with atmospheric pressure changes. Moreover, dose rate is also strongly influenced by the modulation from GCR flux. Numerical simulation and theoretical explanations are required to understand the mechanisms behind these features, and to predict the time variation of radiation environment on the Martian surface if aircraft is supposed to land on it in near future. The high energy galactic cosmic rays (GCRs) which are ubiquitous throughout the solar system are highly penetrating and extremely difficult to shield against beyond the Earth's protective atmosphere and magnetosphere. The goal of this article is to evaluate the long term radiation risk on the Martian surface. Therefore, we need to develop a realistic time-dependent GCR model, which will be integrated with Geant4 transport code subsequently to reproduce the observed variation of surface dose rate associated with the changing heliospheric conditions. In general, the propagation of cosmic rays in the interplanetary medium can be described by a Fokker-Planck equation (or Parker equation). In last decade,we witnessed a fast development of GCR transport models within the heliosphere based on accurate gas-dynamic and MHD backgrounds from global models of the heliosphere. The global MHD simulation produces a more realistic pattern of the 3-D heliospheric structure, as well as the interface between the solar system and the surrounding interstellar space. As a consequence, integrating plasma background obtained from global-dependent 3-D MHD simulation and stochastic Parker transport simulation, we expect to produce an accurate global physical-based GCR modulation model. Combined

  8. Simulation and Comparison of Martian Surface Ionization Radiation

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Zeitlin, Cary; Hassler, Donald M.; Cucinotta, Francis A.

    2013-01-01

    The spectrum of energetic particle radiation and corresponding doses at the surface of Mars is being characterized by the Radiation Assessment Detector (RAD), one of ten science instruments on the Mars Science Laboratory (MSL) Curiosity Rover. The time series of dose rate for the first 300 Sols after landing on Mars on August 6, 2012 is presented here. For the comparison to RAD measurements of dose rate, Martian surface ionization radiation is simulated by utilizing observed space quantities. The GCR primary radiation spectrum is calculated by using the Badhwar-O'Neill 2011 (BO11) galactic cosmic ray (GCR) model, which has been developed by utilizing all balloon and satellite GCR measurements since 1955 and the newer 1997-2012 Advanced Composition Explorer (ACE) measurements. In the BO11 model, solar modulation of the GCR primary radiation spectrum is described in terms of the international smoothed sunspot number and a time delay function. For the transport of the impingent GCR primary radiation through Mars atmosphere, a vertical distribution of atmospheric thickness at each elevation is calculated using the vertical profiles of atmospheric temperature and pressure made by Mars Global Surveyor measurements. At Gale Crater in the southern hemisphere, the seasonal variation of atmospheric thickness is accounted for the daily atmospheric pressure measurements of the MSL Rover Environmental Monitoring Station (REMS) by using low- and high-density models for cool- and warm-season, respectively. The spherically distributed atmospheric distance is traced along the slant path, and the resultant directional shielding by Martian atmosphere is coupled with Curiosity vehicle for dose estimates. We present predictions of dose rate and comparison to the RAD measurements. The simulation agrees to within +/- 20% with the RAD measurements showing clearly the variation of dose rate by heliospheric conditions, and presenting the sensitivity of dose rate by atmospheric pressure

  9. The effect of surface roughness on the transmission of microwave radiation through a planetary surface

    NASA Technical Reports Server (NTRS)

    Golden, L. M.

    1979-01-01

    To account for surface roughness, the transmission of microwave radiation through a planetary surface to an observer is treated by a Monte Carlo technique. Sizable effects are found near the limb of the planet, and they should be included in analyses of high-resolution observations and high-precision integrated disk observations.

  10. Effect of lipid/polysaccharide ratio on surface activity of model root mucilage in its solid and liquid states

    NASA Astrophysics Data System (ADS)

    Chen, Fengxian; Arye, Gilboa

    2016-04-01

    The rhizosphere can be defined as the volume of soil around living roots, which is influenced by root activity. The biological, chemical and physical conditions that prevail in the rhizosphere are significantly different from those of the bulk soil. Plant roots can release diverse organic materials in the rhizosphere which may have different effects on its bio-chemo-physical activity. Among these exudates is the root mucilage which can play a role on the maintenance of root-soil contact, lubrication of the root tip, protection of roots from desiccation and disease, stabilization of soil micro-aggregates and the selective absorption and storage of ions. The surface activity of the root mucilage at the liquid-air interface deduced from its surface tension depression relative to water, implying on its amphiphilic nature. Consequently as the rhizosphere dry out, hydrophobic functional groups may exhibit orientation at the solid-air interface and thus, the wettability of the rhizosphere may temporarily decrease. The major fraction of the root mucilage comprise of polysaccharides and to a much lesser extent, amino acids, organic acids, and phospholipids. The most frequent polysaccharide and phospholipids detected in root mucilage are polygalacturonic acid (PGA) and Phosphatidylcholine (PC), respectively. The latter, is thought to be main cause for the surface active nature of root mucilage. Nevertheless, the role and function of root mucilage in the rhizosphere is commonly studied based on model root mucilage that comprise of only one component, where the most frequent ones are PGA or PC (or lecithin). The main objective of this study was to quantify the effect of concentration and PGA/PC ratios on the wettability of a model rhizosphere soil and the surface tension of the model root mucilage at the liquid-air interface. The PGA/PC mixtures were measured for their equilibrium and dynamic surface tension using the Wilhelmy-Plate method. Quartz sand or glass slides were

  11. Factors related to the quantity of subgingival calculus in proximal root surfaces.

    PubMed

    Martínez-Canut, P; Benlloch, D; Izquierdo, R

    1999-08-01

    The aim of this study was to determine the association between the quantity of subgingival calculus and the following factors: type and severity of periodontal disease, age, gender and tobacco consumption. A sample of 622 periodontal patients was studied. The radiographically detectable subgingival calculus in proximal root surfaces was recorded in periapical radiographs, considering the number of surfaces without calculus and the number of surfaces exhibiting deposits equal or greater than I mm. The association between the subgingival calculus and the factors under study was analyzed by distinct non-parametric tests. A statistically significant association was found between the absence/presence of subgingival calculus and the type and severity of periodontal disease (p<0.001), tobacco consumption (p=0.0049) and age (p<0.001). The quantity of radiographically-detectable subgingival calculus increased with increasing age and severity of the disease. However, the reverse association was found in smokers, which presented more surfaces free of calculus (p=0.0377) and less surfaces exhibiting deposits equal or greater than 1 mm. The amount of subgingival calculus decreased as the quantity of tobacco consumed increased (p=0.0129), and such differences were more significant in those smoker patients with severe periodontitis (p= 0.0065). An explanation is presented to justify these latter findings, since most literature supports that the presence of calculus is higher in smokers. According to the results of this study, more radiographically-detectable subgingival calculus in proximal root surfaces was found with increasing severity of the disease, with increasing age and with the absence of tobacco consumption.

  12. Aeolian removal of dust from radiator surfaces on Mars

    SciTech Connect

    Gaier, J.R.; Perez-Davis, M.E.; Rutledge, S.K.; Hotes, D.

    1994-09-01

    Simulated radiator surfaces made of arc-textured copper and niobium-one percent-zirconium, and ion beam textured graphite and carbon-carbon composite were fabricated and their integrated spectral emittance characterized from 300 to 3000 K. A thin layer of aluminum oxide, basalt, or iron (III) oxide dust was then deposited on them, and they were subjected to low pressure winds in the Martian Surface Wind Tunnel. It has been found that dust deposited on simulated radiator surfaces may or may not seriously lower their integrated spectral emittance, depending upon the characteristics of the dust. With Al{sub 2}O{sub 3} there is no appreciable degradation of emittance on a dusted sample, with basaltic dust there is a 10-20 percent degradation, and with Fe{sub 2}O{sub 3} a 20-40 percent degradation. It was also found that very high winds on dusted highly textured surfaces can result in their abrasion. Degradation in emittance due to abrasion was found to vary with radiator material. Arc-textured copper and Nb-1%Zr was found to be more susceptible to emittance degradation than graphite or carbon-carbon composite. The most abrasion occurred at low angles, peaking at the 22.5{degrees} test samples.

  13. Aeolian removal of dust from radiator surfaces on Mars

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Perez-Davis, Marla E.; Rutledge, Sharon K.; Hotes, Deborah

    1990-01-01

    Simulated radiator surfaces made of arc-textured Cu and Nb-1 percent-Zr and ion beam textured graphite and C-C composite were fabricated and their integrated spectral emittance characterized from 300 to 3000 K. A thin layer of aluminum oxide, basalt, or iron (III) oxide dust was then deposited on them, and they were subjected to low pressure winds in the Martian Surface Wind Tunnel. It was found that dust deposited on simulated radiator surfaces may or may not seriously lower their integrated spectral emittance, depending upon the characteristics of the dust. With Al2O3 there is no appreciable degradation of emittance on a dusted sample, with basaltic dust there is a 10 to 20 percent degradation, and with Fe2O3 a 20 to 40 percent degradation. It was also found that very high winds on dusted highly textured surfaces can result in their abrasion. Degradation in emittance due to abrasion was found to vary with radiator material. Arc-textured Cu and Nb-1 percent Zr was found to be more susceptible to emittance degradation than graphite or C-C composite. The most abrasion occurred at low angles, peaking at the 22.5 deg test samples.

  14. Heat generation on root surfaces after KTP:NdYAG use in endodontic treatment

    NASA Astrophysics Data System (ADS)

    Nammour, S.; Kowalyk, Kenneth; Valici, Ch.; Guillaume, Patrick

    1997-05-01

    The canals of 30 recently extracted human teeth were filled with a photosensitizer. A series of 5 shots, separated by a resting time of 1 second also, was delivered by means of the KTP:YAG fiber tip. The temperature increases were measured on the topical point of the root surfaces by the use of a thermocouple. For laser settings, the rises were always below the safety threshold of 7 C. We conclude that the KTP:NdYAG laser can be harmless for periodontal tissues under some conditions.

  15. Proximity of the mandibular molar root apex from the buccal bone surface: a cone-beam computed tomographic study

    PubMed Central

    Kim, Dokyung; Jin, Myoung-Uk

    2016-01-01

    Objectives The purpose of this study was to evaluate the proximity of the mandibular molar apex to the buccal bone surface in order to provide anatomic information for apical surgery. Materials and Methods Cone-beam computed tomography (CBCT) images of 127 mandibular first molars and 153 mandibular second molars were analyzed from 160 patients' records. The distance was measured from the buccal bone surface to the root apex and the apical 3.0 mm on the cross-sectional view of CBCT. Results The second molar apex and apical 3 mm were located significantly deeper relative to the buccal bone surface compared with the first molar (p < 0.01). For the mandibular second molars, the distance from the buccal bone surface to the root apex was significantly shorter in patients over 70 years of age (p < 0.05). Furthermore, this distance was significantly shorter when the first molar was missing compared to nonmissing cases (p < 0.05). For the mandibular first molars, the distance to the distal root apex of one distal-rooted tooth was significantly greater than the distance to the disto-buccal root apex (p < 0.01). In mandibular second molar, the distance to the apex of C-shaped roots was significantly greater than the distance to the mesial root apex of non-C-shaped roots (p < 0.01). Conclusions For apical surgery in mandibular molars, the distance from the buccal bone surface to the apex and apical 3 mm is significantly affected by the location, patient age, an adjacent missing anterior tooth, and root configuration. PMID:27508159

  16. Radiative energy transport on the surface of an ice sheet

    NASA Astrophysics Data System (ADS)

    Cathles, Lawrence Maclagan, IV

    Both surface roughness and surface conditions of an ice sheet affect the exchange of energy between the atmosphere and an ice sheet. Potential feedbacks exist where the absorbed energy on the surface changes the surface in such a way that more energy is absorbed. One such feedback occurs when a supraglacial lake absorbs energy and sub-lake melting occurs, which deepens the lake, and reduces the albedo. While another feedback exists from topography which creates non-uniform absorption of sunlight, causing surface geometries to change as melting occurs, affecting how energy is absorbed on the surface. The influence of these feedbacks on the surface energy balance of ice sheet are not well understood, and motivate the work presented here. To assess the influences of surface conditions and surface topography on the radiative budget of an ice sheet, the two feedback cases were studied separately. The effect of the surface condition was determined using a two-stream radiative transfer model for a two layer system, where the top layer could be either ice, snow, or water, and the second layer was ice. An analytical solution for the albedo of a supraglacial lake as a function of water depth was derived, and showed that a supraglacial lake can reduce the albedo by fifty percent. Multispectral analysis is required for surfaces where liquid water is present, but little additional accuracy is gained beyond 18 spectral bands. Complex surface topography has a significant effect on the absorption of energy due to multiple reflections between the surface and its self. A numerical model was developed to determine the absorption of insolation on an arbitrary two-dimensional surface. The absorbed radiation forces an ice ablation model evolving the surface topography through an ablation season. Results from numerical simulations show that there is a strong latitudinal dependence on how surface features evolve through an ablation season. At high latitudes, the aspect ratio of surface

  17. The SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) Product

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf; Crow, Wade; Koster, Randal; Kimball, John

    2010-01-01

    The Soil Moisture Active and Passive (SMAP) mission is being developed by NASA for launch in 2013 as one of four first-tier missions recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space in 2007. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, the high resolution soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. In this paper we describe the assimilation of SMAP observations for the generation of the planned SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) product. The SMAP mission makes simultaneous active (radar) and passive (radiometer) measurements in the 1.26-1.43 GHz range (L-band) from a sun-synchronous low-earth orbit. Measurements will be obtained across a 1000 km wide swath using conical scanning at a constant incidence angle (40 deg). The radar resolution varies from 1-3 km over the outer 70% of the swath to about 30 km near the center of the swath. The radiometer resolution is 40 km across the entire swath. The radiometer measurements will allow high-accuracy but coarse resolution (40 km) measurements. The radar measurements will add significantly higher resolution information. The radar is however very sensitive to surface roughness and vegetation structure. The combination of the two measurements allows optimal blending of the advantages of each instrument. SMAP directly observes only surface soil moisture (in the top 5 cm of the soil column). Several of the key applications targeted by SMAP, however, require knowledge of root zone soil moisture (approximately top 1 m of the soil column), which is not directly measured by SMAP. The foremost objective of the SMAP L4_SM product is to fill this gap and provide estimates of root zone soil moisture

  18. Outgroup effects on root position and tree topology in the AFLP phylogeny of a rapidly radiating lineage of cichlid fish☆

    PubMed Central

    Kirchberger, Paul C.; Sefc, Kristina M.; Sturmbauer, Christian; Koblmüller, Stephan

    2014-01-01

    Phylogenetic analyses of rapid radiations are particularly challenging as short basal branches and incomplete lineage sorting complicate phylogenetic inference. Multilocus data of presence-absence polymorphisms such as obtained by AFLP genotyping overcome some of the difficulties, but also present their own intricacies. Here we analyze >1000 AFLP markers to address the evolutionary history of the Limnochromini, a cichlid fish lineage endemic to Lake Tanganyika, and to test for potential effects of outgroup composition on tree topology. The data support previous mitochondrial evidence on the tribe’s taxonomy by confirming the polyphyly of the genus Limnochromis and – in contradiction to a recent taxonomic revision – nesting the genus Greenwoodochromis within the Limnochromini. Species relationships suggest that ecological segregation occurred during the rapid basal radiation of the Limnochromini. The large phylogenetic distance between candidate outgroup taxa and the Limnochromini radiation caused random outgroup effects. Bootstrap support for ingroup nodes was lower in outgroup-rooted than in midpoint-rooted trees, and root positions and ingroup tree topologies varied in response to the composition of the outgroup. These observations suggest that the predisposition for homoplastic evolution makes AFLP-based phylogenetic analyses particularly susceptible to random biases introduced by too-distant outgroup taxa. PMID:24055738

  19. Mars Surface Ionizing Radiation Environment: Need for Validation

    NASA Astrophysics Data System (ADS)

    Wilson, J. W.; Kim, M. Y.; Clowdsley, M. S.; Heinbockel, J. H.; Tripathi, R. K.; Singleterry, R. C.; Shinn, J. L.; Suggs, R.

    1999-01-01

    Protection against the hazards from exposure to ionizing radiation remains an unresolved issue in the Human Exploration and Development of Space (HEDS) enterprise [1]. The major uncertainty is the lack of data on biological response to galactic cosmic ray (GCR) exposures but even a full understanding of the physical interaction of GCR with shielding and body tissues is not yet available and has a potentially large impact on mission costs. "The general opinion is that the initial flights should be short-stay missions performed as fast as possible (so-called 'Sprint' missions) to minimize crew exposure to the zero-g and space radiation environment, to ease requirements on system reliability, and to enhance the probability of mission success." The short-stay missions tend to have long transit times and may not be the best option due to the relatively long exposure to zero-g and ionizing radiation. On the other hand the short-transit missions tend to have long stays on the surface requiring an adequate knowledge of the surface radiation environment to estimate risks and to design shield configurations. Our knowledge of the surface environment is theoretically based and suffers from an incomplete understanding of the physical interactions of GCR with the Martian atmosphere, Martian surface, and intervening shield materials. An important component of Mars surface robotic exploration is the opportunity to test our understanding of the Mars surface environment. The Mars surface environment is generated by the interaction of Galactic Cosmic Rays (GCR) and Solar Particle Events (SPEs) with the Mars atmosphere and Mars surface materials. In these interactions, multiple charged ions are reduced in size and secondary particles are generated, including neutrons. Upon impact with the Martian surface, the character of the interactions changes as a result of the differing nuclear constituents of the surface materials. Among the surface environment are many neutrons diffusing from

  20. Radiation Shielding Options for the Affordable Fission Surface Power System

    SciTech Connect

    Craft, Aaron E.; King, Jeffrey C.

    2009-03-16

    The Affordable Fission Surface Power System (AFSPS) is a proposed power source for an outpost capable of housing six humans for up to six weeks on the lunar surface and emphasizes the design principles of low risk and affordability over high performance. The radiation shield is the most massive component of the reactor system and its effect on launch mass greatly affects the affordability of the AFSPS. Potential shielding materials include lithium hydride, enriched boron-10 carbide, water, borated water, beryllium, boron-doped beryllium and zirconium hydride. Zirconium hydride is the most effective neutron attenuator and also significantly attenuates gamma radiation, but at a significant mass penalty. The other neutron attenuating materials all require the addition of a tungsten layer to provide significant gamma attenuation. Based on neutron radiation alone, lithium hydride is the lightest of the potential attenuators, followed by water and borated water. When gamma radiation is also considered, the lithium hydride/tungsten shield is shown to be the lightest composite shield with a combined mass of 3246 kg, followed by the borated water/tungsten shield (3479 kg). The boron carbide/tungsten shield has a total mass of 4129 kg, but represents significantly less development risk.

  1. SALTS AND RADIATION PRODUCTS ON THE SURFACE OF EUROPA

    SciTech Connect

    Brown, M. E.; Hand, K. P.

    2013-04-15

    The surface of Europa could contain the compositional imprint of an underlying interior ocean, but competing hypotheses differ over whether spectral observations from the Galileo spacecraft show the signature of ocean evaporates or simply surface radiation products unrelated to the interior. Using adaptive optics at the W. M. Keck Observatory, we have obtained spatially resolved spectra of most of the disk of Europa at a spectral resolution {approx}40 times higher than seen by the Galileo spacecraft. These spectra show a previously undetected distinct signature of magnesium sulfate salts on Europa, but the magnesium sulfate is confined to the trailing hemisphere and spatially correlated with the presence of radiation products like sulfuric acid and SO{sub 2}. On the leading, less irradiated, hemisphere, our observations rule out the presence of many of the proposed sulfate salts, but do show the presence of distorted water ice bands. Based on the association of the potential MgSO{sub 4} detection on the trailing side with other radiation products, we conclude that MgSO{sub 4} is also a radiation product, rather than a constituent of a Europa ocean brine. Based on ocean chemistry models, we hypothesize that, prior to irradiation, magnesium is primarily in the form of MgCl{sub 2}, and we predict that NaCl and KCl are even more abundant, and, in fact, dominate the non-ice component of the leading hemisphere. We propose observational tests of this new hypothesis.

  2. Salts and Radiation Products on the Surface of Europa

    NASA Astrophysics Data System (ADS)

    Brown, M. E.; Hand, K. P.

    2013-04-01

    The surface of Europa could contain the compositional imprint of an underlying interior ocean, but competing hypotheses differ over whether spectral observations from the Galileo spacecraft show the signature of ocean evaporates or simply surface radiation products unrelated to the interior. Using adaptive optics at the W. M. Keck Observatory, we have obtained spatially resolved spectra of most of the disk of Europa at a spectral resolution ∼40 times higher than seen by the Galileo spacecraft. These spectra show a previously undetected distinct signature of magnesium sulfate salts on Europa, but the magnesium sulfate is confined to the trailing hemisphere and spatially correlated with the presence of radiation products like sulfuric acid and SO2. On the leading, less irradiated, hemisphere, our observations rule out the presence of many of the proposed sulfate salts, but do show the presence of distorted water ice bands. Based on the association of the potential MgSO4 detection on the trailing side with other radiation products, we conclude that MgSO4 is also a radiation product, rather than a constituent of a Europa ocean brine. Based on ocean chemistry models, we hypothesize that, prior to irradiation, magnesium is primarily in the form of MgCl2, and we predict that NaCl and KCl are even more abundant, and, in fact, dominate the non-ice component of the leading hemisphere. We propose observational tests of this new hypothesis.

  3. Clouds, surface temperature, and the tropical and subtropical radiation budget

    NASA Technical Reports Server (NTRS)

    Dhuria, Harbans L.; Kyle, H. Lee

    1980-01-01

    Solar energy drives both the Earth's climate and biosphere, but the absorbed energy is unevenly distributed over the Earth. The tropical regions receive excess energy which is then transported by atmospheric and ocean currents to the higher latitudes. All regions at a given latitude receive the same top of the atmosphere solar irradiance (insolation). However, the net radiation received from the Sun in the tropics and subtropics varies greatly from one region to another depending on local conditions. Over land, variations in surface albedo are important. Over both land and ocean, surface temperature, cloud amount, and cloud type are also important. The Nimbus-7 cloud and Earth radiation budget (ERB) data sets are used to examine the affect of these parameters.

  4. Radiation shielding in transit to Mars and on the surface

    NASA Astrophysics Data System (ADS)

    Conway, Edmund J.; Townsend, Lawrence W.

    An evaluation is presented of the current understanding of the space radiation environment and the primary considerations of spacecrew exposure effects and limits. By using a two-solar particle event scenario for a 'sprint' mission to Mars, estimates are developed for the requisite shielding of the transfer vehicle and Martian surface habitat. Many uncertainties, however, are noted to have gone into these mission dose estimates; the combination of these uncertainties into an error-bar on shield mass lies beyond current capabilities.

  5. Radiation shielding in transit to Mars and on the surface

    NASA Technical Reports Server (NTRS)

    Conway, Edmund J.; Townsend, Lawrence W.

    1992-01-01

    An evaluation is presented of the current understanding of the space radiation environment and the primary considerations of spacecrew exposure effects and limits. By using a two-solar particle event scenario for a 'sprint' mission to Mars, estimates are developed for the requisite shielding of the transfer vehicle and Martian surface habitat. Many uncertainties, however, are noted to have gone into these mission dose estimates; the combination of these uncertainties into an error-bar on shield mass lies beyond current capabilities.

  6. Comparing the effects of root surface scaling with ultrasound instruments and Er,Cr:YSGG laser.

    PubMed

    Noori, Zohre Tabibzadeh; Fekrazad, Reza; Eslami, Behnam; Etemadi, Ardavan; Khosravi, Shabnam; Mir, Maziar

    2008-07-01

    There are several studies done to show the comparability of laser scaling and root planing with routine methods. The most suitable wavelengths for such an application are reported as 2,940 and 2,780 nm. The superficial interactions of the current wavelength with root surface is investigated in this study to compare the crater and crack formation during the procedures between ultrasound and Er,Cr:yttrium-scandium-gallium garnet (YSGG; 2,780 nm) laser-treated teeth. Thirty human teeth with calculus on their root surface, which were extracted because of the severe periodontitis, were selected for this interventional in vitro study. Calculus area were divided into two equal parts: One of them was prepared for Er,Cr:YSGG (Biolase, Waterlase, USA) laser irradiation and the other one for ultrasound treatment (Dentsply cavitron, DENTSPLY International, USA). The Er,Cr:YSGG laser was specified as follows: pulse energy = 50 mJ, power = 1 W, wavelength = 2,780 nm, pulse repetition rate = 20 pulse per seconds, tip length = 6 mm, and tip diameter = 600 microm. Nineteen of the laser samples (95%) and eight of ultrasound ones (40%) out of 20 samples in each group had craters showing a statistical significant difference (p < 0.001). The number and depth of these craters are also evaluated. Thirteen samples of the laser cases (65%) and all samples of the ultrasound group showed cracks with significant differences (p = 0.008). In addition, the number and width of cracks in both groups are reported. As a general conclusion, the laser-treated samples show more craters but less cracks. PMID:17764026

  7. Simulation of the UV-radiation at the Martian surface

    NASA Astrophysics Data System (ADS)

    Kolb, C.; Stimpfl, P.; Krenn, H.; Lammer, H.; Kargl, G.; Abart, R.; Patel, M. R.

    The UV-radiation at the Martian surface is for several reasons of importance. UV radiation can cause specific damages in the DNA-containing living systems and is involved in the formation of catalytically produced oxidants such as superoxide ions and peroxides. These are capable to oxidize and subsequently destroy organic matter. Lab simulations are necessary to investigate and understand the effects of organic matter removal at the Martian surface. We designed a radiation apparatus which simulates the solar spectrum at the Martian surface between 200 and 700 nm. The system consists of an UV-enhanced xenon arc lamp and special exchangeable filter-sets and mirrors for simulating the effects of the Martian atmospheric column and dust loading. A special collimating system bundles the final parallel beam so that the intensity at the target spot is independent from the distance between the ray source and the sample. The system was calibrated by means of an optical photo-spectrometer to align the ray output with the theoretical target spectrum and to ensure spectral homogeneity. We present preliminary data on calibration and performance of our system, which is integrated in the Austrian Mars simulation facility.

  8. In vitro infrared thermographic assessment of root surface temperature rises during thermafil retreatment using system B.

    PubMed

    Lipski, Mariusz; Woźniak, Krzysztof

    2003-06-01

    The purpose of this in vitro study was to measure the temperature rise on the outer root surface during retreatment of Thermafil using the System B HeatSource. Twenty extracted human maxillary premolars were filled with Thermafil with plastic carriers and divided into two groups of 10 teeth each. In group 1, Thermafil obturators were retrieved using System B HeatSource fitted with a medium plugger at a temperature of 225 degrees C. The plugger was placed first on the buccal, then on the lingual of the plastic carrier for 5 s each. This melted the gutta-percha and softened the plastic carrier. In group 2, Thermafil obturators were retrieved in the same manner except that the heated plugger was placed for 8 s. The temperature changes on the outer root surfaces were recorded using a thermal imaging camera. Thermafil retreatment in vitro using a System B HeatSource causes temperature rises ranging from 26.7 degrees C to 46.0 degrees C. This finding could possibly have implications for creating injury of the periodontal tissues.

  9. Root surface temperature rises in vitro during root canal obturation with thermoplasticized gutta-percha on a carrier or by injection.

    PubMed

    Lipski, Mariusz

    2004-06-01

    The aim of this in vitro study was to measure the temperature rise on the outer root surfaces of teeth during four different root canal obturation techniques. Sixty extracted human maxillary and mandibular premolars with a single canal were used. After root canal cleaning and shaping, the teeth were randomly divided into four groups of 15 teeth each and obturated with Thermafil obturators or Soft-Core obturators using Ultrafil or Trifecta low-temperature thermoplasticized gutta-percha techniques. Temperature changes on the external mesial root surfaces were measured using a thermal imaging camera. Lower temperature rises were found for Ultrafil and Trifecta techniques (2.14 degrees C and 2.03 degrees C, respectively) than for Thermafil and Soft-Core techniques (3.87 degrees C and 3.67 degrees C, respectively). These findings suggest that solid core gutta-percha combined with low-temperature injectable gutta-percha obturation techniques may impose less risk for thermal damage to the surrounding periradicular tissues.

  10. Simultaneous Quantitative and Qualitative Analysis of Flavonoids from Ultraviolet-B Radiation in Leaves and Roots of Scutellaria baicalensis Georgi Using LC-UV-ESI-Q/TOF/MS

    PubMed Central

    Tang, Wen-Ting; Fang, Min-Feng; Liu, Xiao; Yue, Ming

    2014-01-01

    Scutellaria baicalensis Georgi is one of the most widely used traditional Chinese herbal medicines. It has been used for anti-inflammatory, anticancer, antibacterial activities, and so forth. Long-term enhanced ultraviolet-B (UV-B) radiation caused more effect on leaves than on roots of the plant. Liquid chromatography-ultraviolet detection coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (LC-UV-ESI-Q/TOF/MS) method was applied for simultaneous quantitative and qualitative analysis of flavonoids in leaves and roots of S. baicalensis by enhanced UV-B radiation. Both low-intensity radiation and high-intensity radiation were not significantly increaseing the contents of baicalin, wogonoside, and wogonin in roots. However different intensity of radiation has different effects on several flavonoids in leaves. Both low-intensity radiation and high-intensity radiation had no significant effect on contents of baicalin and tectoridin in leaves; the content of scutellarin was significantly decreased by low-intensity radiation; chrysin was detected in low-intensity radiation and high-intensity radiation, and chrysin content is the highest in low-intensity radiation, but chrysin was not detected in control group. Different changes of different flavonoids under enhanced UV-B radiation indicate that induction on flavonoids is selective by enhanced UV-B radiation. PMID:24757579

  11. Changes in Surface Radiation and Associated Effects on Climate

    NASA Astrophysics Data System (ADS)

    Wild, M.

    2005-12-01

    Variations in solar and thermal radiation incident at the Earth's surface profoundly affect the human environment. Increasing greenhouse gas concentrations in the atmosphere enhance the greenhouse effect at the surface manifest as a gradual increase of thermal radiation from the atmosphere down to the surface. Recent analyses of observational records confirm this expectation. Yet not only the thermal fluxes, but also solar fluxes are currently undergoing major changes. A decline of solar radiation at the land surface has become apparent in many observational records prior to 1990, a phenomenon now popularly known as "global dimming." Dimming of solar radiation was probably caused by increased air pollution, and associated levels of aerosol, as well as increasing cloud amounts. The dimming of solar radiation may also be the cause of reduced evaporation between 1960 and 1990 measured worldwide with evaporation pans, documenting the potential influence of solar dimming on the global hydrological cycle. Newly available surface observations from 1990 to present show, however, that the solar dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the mid-1980s. The brightening is consistent with reduction in cloudiness and an atmosphere which has recently become more transparent for sunlight. This has been favored by reduced aerosol loadings related to enhanced air pollution control and the economic breakdown in formerly communist countries in the late 1980s. The transition towards more sunlight at the Earth's surface since the late 1980s after decades of decline may have significantly affected surface climate and the global hydrological cycle. While from the 1960s to the 1980s the dimming of sunlight might have been able to counterbalance and mask to some extent the increasing greenhouse effect, leading to only moderate global temperature changes observed in this period, this has no longer been the case after the mid 1980s. The

  12. Measurement of Net Fluxes of Ammonium and Nitrate at the Surface of Barley Roots Using Ion-Selective Microelectrodes 1

    PubMed Central

    Henriksen, Gordon H.; Raman, D. Raj; Walker, Larry P.; Spanswick, Roger M.

    1992-01-01

    Net fluxes of NH4+ and NO3− into roots of 7-day-old barley (Hordeum vulgare L. cv Prato) seedlings varied both with position along the root axis and with time. These variations were not consistent between replicate plants; different roots showed unique temporal and spatial patterns of uptake. Axial scans of NH4+ and NO3− net fluxes were conducted along the apical 7 centimeters of seminal roots of intact barley seedlings in solution culture using ion-selective microelectrodes in the unstirred layer immediately external to the root surface. Theoretically derived relationships between uptake and concentration gradients, combined with experimental observations of the conditions existing in our experimental system, permitted evaluation of the contribution of bulk water flow to ion movement in the unstirred layer, as well as a measure of the spatial resolution of the microelectrode flux estimation technique. Finally, a method was adopted to assess the accuracy of this technique. PMID:16668947

  13. Scanning electronic microscopy analysis of the apical surface after of root-end resection with different methods.

    PubMed

    Bernardes, Ricardo Affonso; Húngaro Duarte, Marco Antonio; Vivan, Rodrigo Ricci; Baldi, Jarcio V; Vasconcelos, Bruno C; Bramante, Clóvis Monteiro

    2015-01-01

    To compare the time dispensed and the surface characteristics when a root-end resection was performed with a surgical ultrasonic device (VarioSurg, NSK, Japan) or with a Zekrya bur. Forty distal roots of freshly extracted mandibular molars were selected and divided into four different groups: (G1) stainless steel insert with ultrasound; (G2) diamond insert with ultrasound; (G3) stainless steel and diamond inserts with ultrasound, and (G4) Zekrya burs. The time required for the root-end resection was timed and the surface characteristics were evaluated via scanning electronic microscopy. The median times for the root-end resections were: 115.9 s for G1, 249.8 s for G2, 112.7 s for G3, and 7.44 s for G4, the latter presented a smoother root-end surface. There was no statistically significant difference in the comparisons between G3 group and G4 group (Zekrya burs). The other groups where the root-end resections were with ultrasonic devices proportioned a prolonged time to resection with irregular surfaces. PMID:25652816

  14. Melatonin in Glycyrrhiza uralensis: response of plant roots to spectral quality of light and UV-B radiation.

    PubMed

    Afreen, F; Zobayed, S M A; Kozai, T

    2006-09-01

    Melatonin (N-acetyl-5-methoxytryptamine) is known to be synthesized and secreted by the pineal gland in vertebrates. Evidence for the occurrence of melatonin in the roots of Glycyrrhiza uralensis plants and the response of this plant to the spectral quality of light including red, blue and white light (control) and UV-B radiation (280-315 nm) for the synthesis of melatonin were investigated. Melatonin was extracted and quantified in seed, root, leaf and stem tissues and results revealed that the root tissues contained the highest concentration of melatonin; melatonin concentrations also increased with plant development. After 3 months of growth under red, blue and white fluorescent lamps, the melatonin concentrations were highest in red light exposed plants and varied depending on the wavelength of light spectrum in the following order red > blue > or = white light. Interestingly, in a more mature plant (6 months) melatonin concentration was increased considerably; the increments in concentration were X4, X5 and X3 in 6-month-old red, blue and white light exposed (control) plants, respectively. The difference in melatonin concentrations between blue and white light exposed (control) plants was not significant. The concentration of melatonin quantified in the root tissues was highest in the plants exposed to high intensity UV-B radiation for 3 days followed by low intensity UV-B radiation for 15 days. The reduction of melatonin under longer periods of UV-B exposure indicates that melatonin synthesis may be related to the integrated (intensity and duration) value of UV-B irradiation. Melatonin in G. uralensis plant is presumably for protection against oxidative damage caused as a response to UV irradiation.

  15. Comparison of Different Global Information Sources Used in Surface Radiative Flux Calculation: Radiative Properties of the Surface

    NASA Technical Reports Server (NTRS)

    Zhang, Yuanchong; Rossow, William B.; Stackhouse, Paul W., Jr.

    2007-01-01

    Direct estimates of surface radiative fluxes that resolve regional and weather-scale variabilty over the whole globe with reasonable accuracy have only become possible with the advent of extensive global, mostly satellite, datasets within the past couple of decades. The accuracy of these fluxes, estimated to be about 10-15 W per square meter is largely limited by the accuracy of the input datasets. The leading uncertainties in the surface fluxes are no longer predominantly induced by clouds but are now as much associated with uncertainties in the surface and near-surface atmospheric properties. This study presents a fuller, more quantitative evaluation of the uncertainties for the surface albedo and emissivity and surface skin temperatures by comparing the main available global datasets from the Moderate-Resolution Imaging Spectroradiometer product, the NASA Global Energy and Water Cycle Experiment Surface Radiation Budget project, the European Centre for Medium-Range Weather Forecasts, the National Aeronautics and Space Administration, the National Centers for Environmental Prediction, the International Satellite Cloud Climatology Project (ISCCP), the Laboratoire de Meteorologie Dynamique, NOAA/NASA Pathfinder Advanced Very High Resolution Radiometer project, NOAA Optimum Interpolation Sea Surface Temperature Analysis and the Tropical Rainfall Measuring Mission (TRMM) Microwave Image project. The datasets are, in practice, treated as an ensemble of realizations of the actual climate such that their differences represent an estimate of the uncertainty in their measurements because we do not possess global truth datasets for these quantities. The results are globally representative and may be taken as a generalization of our previous ISCCP-based uncertainty estimates for the input datasets. Surface properties have the primary role in determining the surface upward shortwave (SW) and longwave (LW) flux. From this study, the following conclusions are obtained

  16. Surface plasmon amplification by stimulated emission of radiation: quantum generation of coherent surface plasmons in nanosystems.

    PubMed

    Bergman, David J; Stockman, Mark I

    2003-01-17

    We make a step towards quantum nanoplasmonics: surface plasmon fields of a nanosystem are quantized and their stimulated emission is considered. We introduce a quantum generator for surface plasmon quanta and consider the phenomenon of surface plasmon amplification by stimulated emission of radiation (spaser). Spaser generates temporally coherent high-intensity fields of selected surface plasmon modes that can be strongly localized on the nanoscale, including dark modes that do not couple to far-zone electromagnetic fields. Applications and related phenomena are discussed. PMID:12570577

  17. The Martian Radiation Environment from Orbit and on the Surface

    NASA Technical Reports Server (NTRS)

    Reedy, R. C.; Howe, S. D.

    1999-01-01

    A good knowledge of the Martian radiation environment and its interactions with Mars is needed for many reasons. It is needed to help unfold the results of the Mars-2001 orbiter's gamma-ray spectrometer (GRS) and neutron spectrometers (NS) to determine elemental abundances on the Martian surface. It is needed to interpret the measurements of the Martian Radiation Environment Experiments (MARIE) on both the Mars 2001 orbiter and lander. It is needed to calculate production rates of cosmogenic nuclides that will be measured in samples returned from Mars. It is needed to determine the doses that astronauts would receive in Martian orbit and especially on the surface of Mars. We discuss the two types of energetic particles in the vicinity of Mars and the nature of their interactions. Solar energetic particles (SEPs) occur very rarely but can have high fluxes that are dangerous in space. However, their energies are low enough that few solar energetic particles reach the surface of Mars. Their interactions can be fairly easily modeled because SEPs create few secondary particles. Galactic cosmic rays (GCRs) have high energies and are the dominant source of energetic particles on the Martian surface, mainly secondary neutrons. Modeling their interactions is complicated because of the range of nuclei in the GCR and their high energies. Work at Los Alamos on GCR interactions will be presented.

  18. Effects of the Nd:YAG laser and combined treatments on in vitro fibroblast attachment to root surfaces.

    PubMed

    Thomas, D; Rapley, J; Cobb, C; Spencer, P; Killoy, W

    1994-01-01

    The purpose of this in vitro study was to evaluate the effects of the Nd:YAG laser either alone or in combination with root planning or air-powder abrasive treatment on fibroblast attachment to non-diseased root surfaces. 28, 4 x 4 mm root specimens and four disc-shaped root specimens 6 mm in diameter were obtained from unerupted 3rd molars. The root segments were randomly assigned to 4 treatment groups: (1) control; (2) laser-only treated; (3) laser treated followed by root planning; (4) laser treated followed by air-powder abrasive treatment. Laser-treated root specimens were exposed for 1 min with the Nd:YAG laser calibrated at an energy setting of 75 mJ at 20 pulses/s using a 320 microns contact fiber. The contact fiber was held parallel to the root segments and the root segments were kept moist with distilled water. Following the prescribed treatments, the root specimens were incubated with fibroblast cultures and then prepared for SEM examination. Results of cell counts of fibroblasts attached to specimens within each treatment group yielded the following means and standard deviations: control groups, 181.64 +/- 44.74; lased only, 78.57 +/- 21.35; lased and root planed 125.35 +/- 26.13; and lased followed by an air-powder abrasive, 177.28 +/- 55.71. Application of ANOVA followed by the Dunn Multiple Comparison test revealed significant differences (p < 0.01) in the number of attached cells between the control and laser-only treated groups; and between the laser-only and laser/air-powder abrasive treated groups.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8126242

  19. Computer-based video digitizer analysis of surface extension in maize roots: kinetics of growth rate changes during gravitropism

    NASA Technical Reports Server (NTRS)

    Ishikawa, H.; Hasenstein, K. H.; Evans, M. L.

    1991-01-01

    We used a video digitizer system to measure surface extension and curvature in gravistimulated primary roots of maize (Zea mays L.). Downward curvature began about 25 +/- 7 min after gravistimulation and resulted from a combination of enhanced growth along the upper surface and reduced growth along the lower surface relative to growth in vertically oriented controls. The roots curved at a rate of 1.4 +/- 0.5 degrees min-1 but the pattern of curvature varied somewhat. In about 35% of the samples the roots curved steadily downward and the rate of curvature slowed as the root neared 90 degrees. A final angle of about 90 degrees was reached 110 +/- 35 min after the start of gravistimulation. In about 65% of the samples there was a period of backward curvature (partial reversal of curvature) during the response. In some cases (about 15% of those showing a period of reverse bending) this period of backward curvature occurred before the root reached 90 degrees. Following transient backward curvature, downward curvature resumed and the root approached a final angle of about 90 degrees. In about 65% of the roots showing a period of reverse curvature, the roots curved steadily past the vertical, reaching maximum curvature about 205 +/- 65 min after gravistimulation. The direction of curvature then reversed back toward the vertical. After one or two oscillations about the vertical the roots obtained a vertical orientation and the distribution of growth within the root tip became the same as that prior to gravistimulation. The period of transient backward curvature coincided with and was evidently caused by enhancement of growth along the concave and inhibition of growth along the convex side of the curve, a pattern opposite to that prevailing in the earlier stages of downward curvature. There were periods during the gravitropic response when the normally unimodal growth-rate distribution within the elongation zone became bimodal with two peaks of rapid elongation separated by

  20. Conjugate natural convection flow over a vertical surface with radiation

    NASA Astrophysics Data System (ADS)

    Siddiqa, Sadia; Hossain, Md. Anwar; Gorla, Rama Subba Reddy

    2016-06-01

    Numerical study of conjugate natural convection flow over a finite vertical surface with radiation is reported in this article. Rosseland diffusion approximation is used to express the radiative heat flux term. The governing boundary-layer equations are made dimensionless by means of a suitable form of non-similarity transformation. These equations are obtained in three regimes: (1) upstream (when ξ → 0), (2) downstream (when ξ → ∞ ) and (3) entire regime and are solved numerically. The solutions in the upstream and downstream regimes are obtained via shooting method whereas two-point implicit finite difference method is used to get the solutions for the entire regime. It is seen that asymptotic solutions give accurate results when compared with the numerical solution of the entire regime. The results indicate that the flow field and the temperature distributions are greatly influenced by thermal radiation parameter , R_d, surface temperature parameter, θ _w and Prandtl number Pr. It is established from the analysis that recirculation occurs in the flow specifically for R_d=1.5.

  1. Radiative interactions with micromachined surfaces: Spectral polarized emittance. Final report

    SciTech Connect

    Zemel, J.N.

    1995-05-01

    This report covers work aimed at obtaining additional information on the electromagnetic emissions from heated, microstructured surface. Earlier work had established that thermal emission was a useful means for obtaining broad band information on the electromagnetic properties of these surfaces. Among the earlier results obtained was a demonstration that there was an increased amount of coherent radiation emitted from these structures. Also found was that the nature of the emission was dependent on the carrier concentration of the emitting material as well as the details of the geometry of surface structures. Described in this report is the normal polarized emissivity of undoped silicon gratings of different dimensions measured with a new emissometer. Deep grating fabrication, formation of a titanium silicide layer, and wafer cutting is described.

  2. Radiative Properties of Smoke and Aerosol Over Land Surfaces

    NASA Technical Reports Server (NTRS)

    King, Michael D.

    2000-01-01

    This talk discusses smoke and aerosol's radiative properties with particular attention to distinguishing the measurement over clear sky from clouds over land, sea, snow, etc. surfaces, using MODIS Airborne Simulator data from (Brazil, arctic sea ice and tundra and southern Africa, west Africa, and other ecosystems. This talk also discusses the surface bidirectional reflectance using Cloud Absorption Radiometer, BRDF measurements of Saudi Arabian desert, Persian Gulf, cerrado and rain forests in Brazil, sea ice, tundra, Atlantic Ocean, Great Dismal Swamp, Kuwait oil fire smoke. Recent upgrades to instrument (new TOMS UVA channels at 340 and 380 planned use in Africa (SAFARI 2000) and possibly for MEIDEX will also be discussed. This talk also plans to discuss the spectral variation of surface reflectance over land and the sensitivity of off-nadir view angles to correlation between visible near-infrared reflectance for use in remote sensing of aerosol over land.

  3. The influence of root surface distance to alveolar bone and periodontal ligament on periodontal wound healing

    PubMed Central

    2016-01-01

    Purpose The purpose of this animal study was to perform a 3-dimensional micro-computed tomography (micro-CT) analysis in order to investigate the influence of root surface distance to the alveolar bone and the periodontal ligament on periodontal wound healing after a guided tissue regeneration (GTR) procedure. Methods Three adult Sus scrofa domesticus specimens were used. The study sample included 6 teeth, corresponding to 2 third mandibular incisors from each animal. After coronectomy, a circumferential bone defect was created in each tooth by means of calibrated piezoelectric inserts. The experimental defects had depths of 3 mm, 5 mm, 7 mm, 9 mm, and 11 mm, with a constant width of 2 mm. One tooth with no defect was used as a control. The defects were covered with a bioresorbable membrane and protected with a flap. After 6 months, the animals were euthanised and tissue blocks were harvested and preserved for micro-CT analysis. Results New alveolar bone was consistently present in all experimental defects. Signs of root resorption were observed in all samples, with the extent of resorption directly correlated to the vertical extent of the defect; the medial third of the root was the most commonly affected area. Signs of ankylosis were recorded in the defects that were 3 mm and 7 mm in depth. Density and other indicators of bone quality decreased with increasing defect depth. Conclusions After a GTR procedure, the periodontal ligament and the alveolar bone appeared to compete in periodontal wound healing. Moreover, the observed decrease in bone quality indicators suggests that intrabony defects beyond a critical size cannot be regenerated. This finding may be relevant for the clinical application of periodontal regeneration, since it implies that GTR has a dimensional limit. PMID:27800213

  4. Root Surface Roughness After Scaling and Root Planing with Er:YAG Laser Compared to Hand and Ultrasonic Instruments by Profilometry

    PubMed Central

    Yaghini, Jaber; Naghsh, Narges; Attaei, Elaheh; Birang, Reza; Birang, Ehsan

    2015-01-01

    Objectives: Scaling and root planing (SRP) is one of the most commonly used procedures during periodontal treatment. The aim of this study was to evaluate the root surface roughness after SRP with erbium: yttrium aluminum garnet (Er:YAG) laser compared to ultrasonic and hand instruments. Materials and Methods: In this experimental study, 56 extracted sound single-rooted teeth with moderate level of calculus were selected and randomly divided into four groups: SRP was performed with Er:YAG laser (100 mJ pulse, 1W, 10Hz, VSP and contact mode, with 50% water and air) in group one, hand instrument in group two and ultrasonic tool in group three. Group four was considered as the control group. After SRP, all samples were cut by Servocut cutting machine into pieces with 3×3×2mm dimensions. The samples were mounted in acrylic resin. The surface roughness of the samples was evaluated with profilometry, and the data were analyzed using one-way ANOVA and Tukey’s test in SPSS software. Results: Surface roughness was higher in laser and lower in ultrasonic group compared to other groups. There was a significant difference in surface roughness between laser and ultrasonic groups (P=0.043), but there was no significant difference in surface roughness among other groups (P>0.05). Conclusion: The results of this study showed that surface roughness after SRP with Er:YAG laser was not higher than that after manual SRP, but the former value was higher than that after SRP with ultrasonic instrument. PMID:27559349

  5. Dependence of phenanthrene dissipation in mangrove sediment on the distance to root surface of Kandelia obovata L.

    PubMed

    Fang, Yu; Yan, Chong-Ling; Du, Jing-Na; Yu, Jun-Yi

    2012-07-01

    We explored the relationship between the distance from roots and rhizosphere-mediated phenanthrene (PHE) dissipation in planted mangrove sediment. A compartmentalized device (rhizobox) was used that separated root surface and four consecutive rhizosphere layers that extended 0-2, 2-4, 4-6, and >6 mm away from the root surface. Kandelia obovata L. Druce seedlings were grown for 4 months in sediment spiked with 10 mgkg(-1) PHE. PHE dissipation, microbial community structure and enzymatic activities at millimeter scale in the vicinity of plant roots were analyzed. Results indicated significant differences in PHE dissipation through the various layers in the planted rhizobox. PHE dissipation exhibited the most rapid loss in the 0-2 mm near-rhizosphere layer, the lowest in far-rhizosphere (>6 mm) layer. Microbial community structure as indicated by denaturing gradient gel electrophoresis (DGGE) profiles showed that special bacterial species and larger bacterial numbers were observed in near-rhizosphere layers. Depending on the distance to root surface, near-rhizosphere bacterial species and enzymatic activities were more abundant than root compartment and far-rhizosphere, resulting in rapid dissipation of PHE. PMID:22908629

  6. Extension of Kirchhoff's formula to radiation from moving surfaces

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Myers, M. K.

    1988-01-01

    Kirchhoff's formula for radiation from a closed surface has been used recently for prediction of the noise of high speed rotors and propellers. Because the closed surface on which the boundary data are prescribed in these cases is in motion, an extension of Kirchhoff's formula to this condition is required. In this paper such a formula, obtained originally by Morgans for the interior problem, is derived for regions exterior to surfaces moving at speeds below the wave propagation speed by making use of some results of generalized function theory. It is shown that the usual Kirchhoff formula is a special case of the main result of the paper. The general result applies to a deformable surface. However, the special form it assumes for a rigid surface in motion is also noted. In addition, Morgans' result is further extended by showing that edge line integrals appear in the formula when applied to a surface that is piecewise smooth. Some possible areas of application of the formula to problems of current interest in aeroacoustics are discussed.

  7. Extension of Kirchhoff's formula to radiation from moving surfaces

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Myers, M. K.

    1987-01-01

    Kirchhoff's formula for radiation from a closed surface has been used recently for prediction of the noise of high speed rotors and propellers. Because the closed surface on which the boundary data are prescribed in these cases is in motion, an extension of Kirchhoff's formula to this condition is required. In this paper such a formula, obtained originally by Morgans for the interior problem, is derived for regions exterior to surfaces moving at speeds below the wave propagation speed by making use of some results of generalized function theory. It is shown that the usual Kirchhoff formula is a special case of the main result of the paper. The general result applies to a deformable surface. However, the special form it assumes for a rigid surface in motion is also noted. In addition, Morgans' result is further extended by showing that edge line integrals appear in the formula when applied to a surface that is piecewise smooth. Some possible areas of application of the formula to problems of current interest in aeroacoustics are discussed.

  8. Gravitational radiation antennas - History, observations, and lunar surface opportunities

    NASA Astrophysics Data System (ADS)

    Weber, J.

    1990-03-01

    The paper discusses the suitability of the lunar surface for observing the quadrupole modes with a long-period accelerometer as well as gravitational radiation by means of a low-frequency bar and interferometer antennas. The theoretical background of gravitational radiation antennas is described emphasizing the General theory of Relativity. One measurement method involves the use of an elastic solid such as an aluminum cylinder whose length changes as spacetime curvature changes. The second method described involves the use of a Michelson interferometer which measures fractional changes in length. Results of the measurements are given for the period during the supernova 1987A, and applications of the experimental apparatuses to lunar gravitational observations are discussed. The large cross sections of the lunar quadrupole modes make the moon a good place for the use of a long-period accelerometer.

  9. Contribution of root respiration to soil surface CO2 flux in a boreal black spruce chronosequence.

    PubMed

    Bond-Lamberty, Ben; Wang, Chuankuan; Gower, Stith T

    2004-12-01

    We quantified the contributions of root respiration (RC) and heterotrophic respiration to soil surface CO2 flux (RS) by comparing trenched and untrenched plots in well-drained and poorly drained stands of a black spruce (Picea mariana (Mill.) BSP) fire chronosequence in northern Manitoba, Canada. Our objectives were to: (1) test different equations for modeling RS as a function of soil temperature; and (2) model annual RS and RC for the chronosequence from continuous soil temperature measurements. The choice of equation to model RS strongly affected annual RS and RC, with an Arrhenius-based model giving the best fit to the data, especially at low temperatures. Modeled values of annual RS were positively correlated with soil temperature at 2-cm depth and were affected by year of burn and trenching, but not by soil drainage. During the growing season, measured RC was low in May, peaked in late July and declined to low values by the end of the growing season. Annual RC was < 5% of RS in the recently burned stands, approximately 40% in the 21-year-old stands and 5-15% in the oldest (152-year-old) stands. Evidence suggests that RC may have been underestimated in the oldest stands, with residual root decay from trenching accounting for 5-10% of trenched plot RS at most sites. PMID:15465701

  10. Intracanal Antibiotic Medication for Sustained Root Surface Disinfection–A Laboratory Evaluation

    PubMed Central

    Zaruba, Markus Tobias Winfried; Filli, Tilla; Rechenberg, Dan-Krister; Thurnheer, Thomas; Attin, Thomas; Schmidlin, Patrick Roger

    2015-01-01

    Purpose: To measure the release of an antibiotic mixture of ciprofloxacin, cerfuroxim and metronidazole (TreVitaMix, TVM) through human dentine and to assess the growth inhibition of Fusobacterium nucleatum. Material and Methods: Twenty-four extracted human incisors were scaled and endodontically treated. Root canals were either filled with antibiotic tri-mixture (TVM) or with the carrier material alone (propylene glycol, PG) and were coronally and apically sealed with a flowable composite. Transradicular medicament release was spectrophotometrically measured at 277 nm in simulated body fluid for up to 21 days. In a second part, an agar diffusion assay (F. nucleatum) with representative TVM concentrations as determined in the first part was performed to study the growth inhibition. Samples were anaerobical incubated for 48 h and inhibition zones were measured. Results: TVM was spectrophotometrically detectable in the immersion solution and released in decreasing concentrations up to 21 days (222.5 ± 65.2 mg/ml at day 1 and 35.1 ± 15.6 mg/ml at day 21). In addition, inhibition zones were shown in the agar diffusion assay at representative TVM concentrations. The carrier material showed no antibacterial effect. Conlusion: TVM showed the potential to penetrate through dentine and to inhibit bacterial growth. Therefore, it might have the potential to disinfect the outer root surface in perio-endo lesions, but further research is needed to confirm these observations. PMID:26966464

  11. Surface summertime radiative forcing by shallow cumuli at the Atmospheric Radiation Measurement Southern Great Plains site

    SciTech Connect

    Berg, Larry K.; Kassianov, Evgueni I.; Long, Charles N.; Mills Jr., David L.

    2011-01-08

    Although shallow cumuli are common over large areas of the globe, their impact on the surface radiative forcing has not been carefully evaluated. This study addresses this shortcoming by analyzing data from days with shallow cumuli collected over eight summers (2000-2007) at the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility (collectively ACRF) Southern Great Plains site. During periods with clouds, the average shortwave and longwave radiative forcings are 45.5 W m-2 and +11.6 W m-2, respectively. The forcing has been defined so that a negative (positive) forcing indicates a surface cooling (warming). On average, the shortwave forcing is negative, however, instances with positive shortwave forcing are observed approximately 20% of the time. These positive values of shortwave forcing are associated with three-dimensional radiative effects of the clouds. The three-dimensional effects are shown to be largest for intermediate cloud amounts. The magnitude of the three-dimensional effects decreased with averaging time, but it is not negligibly small even for large averaging times as long as four hours.

  12. Global Surface Ultraviolet Radiation Climatology from TOMS and ERBE Data

    NASA Technical Reports Server (NTRS)

    Lubin, Dan

    1998-01-01

    The overall goal of this project has been to develop a method for calculating the distribution of solar ultraviolet radiation (UVR) over most of the earth's surface using NASA's Total Ozone Mapping Spectrometer (TOMS) and Earth Radiation Budget Experiment (ERBE) data, and to use this method to develop a UVR climatology that is useful in the context of the global ozone depletion issue. The research carried out with this support has resulted the following accomplishments: (1) a radioactive transfer method. based on the delta-Eddington approximation, was successfully developed; (2) the method was applied to the five years of overlapping TOMS and ERBE Monthly-Hourly data to examine the impact of global variability in cloud cover on trends in surface UVR; (3) a presentation was made on effects of stratospheric ozone depletion; (4) the radioactive transfer model was finally applied to all daylight hours to make a through study of the global effect of cloud cover;and (6) a five-year global climatology of surface UVR based on all of the research has been prepared for general distribution.

  13. Charactering the Surface Radiation Budget over the Tibetan Plateau Using Ground Observations, Reanalysis, and Satellite Datasets

    NASA Astrophysics Data System (ADS)

    Shi, Q.; Liang, S.

    2013-12-01

    The importance of the surface radiation budget (SRB) over the Tibetan Plateau (TP) to impact not only the local climate but also the remote area (i.e., the drought and flood in China) attracts increasing attentions in the scientific communities. Observed evidences support a continuous dimming trend with predominant warming, wind stilling, and moistening trends since 1980s. Cautions, however, need to be exercised when using ground observations or satellite retrievals alone, which are limited with large errors and sparse distributions, respectively. This study aims to characterize the monthly SRB at 0.5° over the TP extending two decades by incorporating multiple datasets, including ground-measured datasets, reanalysis datasets, and satellite datasets. The fused SRB was first generated using a multiple linear regression method to synthesize reanalysis and satellite datasets with ground observations from 1984 to 2007, and was then applied not only to analyze the characteristics (spatial distribution, temporal variation, and trend) of the SRB but also to compare with selected atmospheric (cloud cover, precipitation, and water vapor) and surface (temperature, snow cover, and the Normalized Difference Vegetation Index (NDVI)) anomalies over the TP. The cross validation results suggested that the fused data lowered the root mean square errors (RMSEs) at the monthly scale (<19 W/m2) by constraining uncertainties from multiple sources (i.e., inputs, preprocessing, and data fusion). The major finding is that the interaction of solar dimming with changes of surface albedo has dominated the marked decrease of all-wave net radiation since the mid-1980s regardless of the increase of downward longwave radiation (that counteracts the increase of upward longwave radiation). Furthermore, the weakening and strengthening of the relationships between the components of SRB and the correlated variables of atmospheric or surface conditions exhibit a seasonal dependency over the TP, where

  14. Response of nickel surface to pulsed fusion plasma radiations

    SciTech Connect

    Niranjan, Ram Rout, R. K. Srivastava, R. Gupta, Satish C.; Chakravarthy, Y.; Patel, N. N.; Alex, P.

    2014-04-24

    Nickel based alloys are being projected as suitable materials for some components of the next generation fusion reactor because of compatible thermal, electrical and mechanical properties. Pure nickel material is tested here for possibility of similar application purpose. Nickel samples (> 99.5 % purity) are exposed here to plasma radiations produced due to D-D fusion reaction inside an 11.5 kJ plasma focus device. The changes in the physical properties of the nickel surface at microscopic level which in turn change the mechanical properties are analyzed using scanning electron microscope, optical microscope, glancing incident X-ray diffractometer and Vicker's hardness gauge. The results are reported here.

  15. Response of nickel surface to pulsed fusion plasma radiations

    NASA Astrophysics Data System (ADS)

    Niranjan, Ram; Rout, R. K.; Srivastava, R.; Chakravarthy, Y.; Patel, N. N.; Alex, P.; Gupta, Satish C.

    2014-04-01

    Nickel based alloys are being projected as suitable materials for some components of the next generation fusion reactor because of compatible thermal, electrical and mechanical properties. Pure nickel material is tested here for possibility of similar application purpose. Nickel samples (> 99.5 % purity) are exposed here to plasma radiations produced due to D-D fusion reaction inside an 11.5 kJ plasma focus device. The changes in the physical properties of the nickel surface at microscopic level which in turn change the mechanical properties are analyzed using scanning electron microscope, optical microscope, glancing incident X-ray diffractometer and Vicker's hardness gauge. The results are reported here.

  16. Large Scale Surface Radiation Budget from Satellite Observation

    NASA Technical Reports Server (NTRS)

    Pinker, R. T.

    1995-01-01

    During the current reporting period, the focus of our work was on preparing and testing an improved version of our Surface Radiation Budget algorithm for processing the ISCCP D1 data routinely at the SRB Satellite Data Analysis Center (SDAC) at NASA Langley Research Center. The major issues addressed are related to gap filling and to testing whether observations made from ERBE could be used to improve current procedures of converting narrowband observations, as available from ISCCP, into broadband observations at the TOA. The criteria for selecting the optimal version are to be based on results of intercomparison with ground truth.

  17. Variability of surface solar radiation in unforced CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Folini, Doris; Wild, Martin

    2016-04-01

    We examine the natural variability of surface solar radiation (SSR) under pre-industrial conditions with time-invariant forcing in control runs in global climate simulations of the latest coupled model intercomparison project, CMIP5. We consider global and regional scales, as well as annual and seasonal data. Special emphasis is given to the likelihood of spurious SSR trends. To address this question, we determine for each model the range of linear SSR trends as function of the number of years over which the trend is taken. We discuss our findings with regard to potential aerosol induced dimming and its detectability in the second half of the 20th century.

  18. Impact of buildings on surface solar radiation over urban Beijing

    NASA Astrophysics Data System (ADS)

    Zhao, Bin; Liou, Kuo-Nan; Gu, Yu; He, Cenlin; Lee, Wee-Liang; Chang, Xing; Li, Qinbin; Wang, Shuxiao; Tseng, Hsien-Liang R.; Leung, Lai-Yung R.; Hao, Jiming

    2016-05-01

    The rugged surface of an urban area due to varying buildings can interact with solar beams and affect both the magnitude and spatiotemporal distribution of surface solar fluxes. Here we systematically examine the impact of buildings on downward surface solar fluxes over urban Beijing by using a 3-D radiation parameterization that accounts for 3-D building structures vs. the conventional plane-parallel scheme. We find that the resulting downward surface solar flux deviations between the 3-D and the plane-parallel schemes are generally ±1-10 W m-2 at 800 m grid resolution and within ±1 W m-2 at 4 km resolution. Pairs of positive-negative flux deviations on different sides of buildings are resolved at 800 m resolution, while they offset each other at 4 km resolution. Flux deviations from the unobstructed horizontal surface at 4 km resolution are positive around noon but negative in the early morning and late afternoon. The corresponding deviations at 800 m resolution, in contrast, show diurnal variations that are strongly dependent on the location of the grids relative to the buildings. Both the magnitude and spatiotemporal variations of flux deviations are largely dominated by the direct flux. Furthermore, we find that flux deviations can potentially be an order of magnitude larger by using a finer grid resolution. Atmospheric aerosols can reduce the magnitude of downward surface solar flux deviations by 10-65 %, while the surface albedo generally has a rather moderate impact on flux deviations. The results imply that the effect of buildings on downward surface solar fluxes may not be critically significant in mesoscale atmospheric models with a grid resolution of 4 km or coarser. However, the effect can play a crucial role in meso-urban atmospheric models as well as microscale urban dispersion models with resolutions of 1 m to 1 km.

  19. Rhizophagus irregularis MUCL 41833 can colonize and improve P uptake of Plantago lanceolata after exposure to ionizing gamma radiation in root organ culture.

    PubMed

    Kothamasi, David; Wannijn, Jean; van Hees, May; Nauts, Robin; van Gompel, Axel; Vanhoudt, Nathalie; Cranenbrouck, Sylvie; Declerck, Stéphane; Vandenhove, Hildegarde

    2016-04-01

    Long-lived radionuclides such as (90)Sr and (137)Cs can be naturally or accidentally deposited in the upper soil layers where they emit β/γ radiation. Previous studies have shown that arbuscular mycorrhizal fungi (AMF) can accumulate and transfer radionuclides from soil to plant, but there have been no studies on the direct impact of ionizing radiation on AMF. In this study, root organ cultures of the AMF Rhizophagus irregularis MUCL 41833 were exposed to 15.37, 30.35, and 113.03 Gy gamma radiation from a (137)Cs source. Exposed spores were subsequently inoculated to Plantago lanceolata seedlings in pots, and root colonization and P uptake evaluated. P. lanceolata seedlings inoculated with non-irradiated AMF spores or with spores irradiated with up to 30.35 Gy gamma radiation had similar levels of root colonization. Spores irradiated with 113.03 Gy gamma radiation failed to colonize P. lanceolata roots. P content of plants inoculated with non-irradiated spores or of plants inoculated with spores irradiated with up to 30.35 Gy gamma radiation was higher than in non-mycorrhizal plants or plants inoculated with spores irradiated with 113.03 Gy gamma radiation. These results demonstrate that spores of R. irregularis MUCL 41833 are tolerant to chronic ionizing radiation at high doses. PMID:26467250

  20. The Martian surface radiation environment - Influence of higher atmospheric pressure and surface or sub-surface water

    NASA Astrophysics Data System (ADS)

    Ehresmann, B.; Böhm, E.; Kohler, J.; Martin, C.; Wimmer-Schweingruber, R. F.; Reitz, G.; Hassler, D. M.; Zeitlin, C. J.

    2011-12-01

    The Noachian epoch (~4.5 - 3.5 billion years ago) is a promising era for a possible emergence of life on Mars. The presence of runoff channels in areas formed during the Noachian suggests that liquid water existed at least sporadically during that time, with liquid water being regarded as a prerequisite for life. To have sustained liquid water, the atmospheric pressure on Noachian Mars must have been significantly higher than in the present. When considering the possibility of life on Noachian Mars, one conceivable restriction is given by the ionizing radiation environment. Using PLANETOCOSMICS- and GEANT4-simulation codes, we calculate the radiation environment on the Martian surface and the resulting radiation exposure for different atmospheric conditions. Here, we present absorbed dose rates resulting from galactic-cosmic-proton and alpha-particle-induced radiation environments, as well as changes of these rates caused by an increase of atmospheric pressure. Furthermore, we analyze which influence the presence of liquid surface water or sub-surface water-ice would have on the radiation environment under these different atmospheric conditions.

  1. Toward Improved Solar Irradiance Forecasts: Comparison of Downwelling Surface Shortwave Radiation in Arizona Derived from Satellite with the Gridded Datasets

    NASA Astrophysics Data System (ADS)

    Kim, Chang Ki; Holmgren, William F.; Stovern, Michael; Betterton, Eric A.

    2016-08-01

    The downwelling surface shortwave radiation derived from geostationary satellite imagery was compared with the available datasets for the Southwestern United States. The averaged root mean square errors for our instantaneous estimates ranged from 95.0 to 122.7 W m-2, which is lower than those derived from the MODerate resolution Imaging Spectroradiometer (MODIS). The Modern Era Retrospective-analysis for Research and Applications (MERRA) products were used to compare the hourly mean solar insolation. The three hourly mean downwelling surface shortwave radiation was evaluated by comparing the North American Regional Reanalysis (NARR) and the Clouds and the Earth's Radiant Energy System (CERES) products. Our estimates show the better performance than MERRA, NARR and CERES datasets because of coarse resolution that limits determining the solar dimming due to small clouds.

  2. Surface modification of nanoparticles for radiation curable acrylate clear coatings

    NASA Astrophysics Data System (ADS)

    Bauer, F.; Gläsel, H.-J.; Hartmann, E.; Bilz, E.; Mehnert, R.

    2003-08-01

    To obtain transparent, scratch and abrasion resistant coatings a high content of nanosized silica and alumina filler was embedded in radiation-curable acrylate formulations by acid catalyzed silylation using trialkoxysilanes. 29SiMAS NMR and MALDI-TOF mass spectrometry were employed to elucidate the structure of the surface-grafted methacryloxypropyl-, vinyl- and n-propyl-trimethoxysilane. In accordance with NMR findings, MALDI-TOF MS showed highly condensed oligomeric siloxanes of more than 20 monomeric silane units. A ladder-like structure of bound polysiloxanes is proposed rather than a simplified picture of tridentate silane bonding. Hence, silane coupling agents do not only modify the chemical nature of the filler surface but also strongly effect the rheological properties of the acrylate nanodispersions.

  3. On surface Raman scattering and luminescence radiation in boron carbide.

    PubMed

    Werheit, H; Filipov, V; Schwarz, U; Armbrüster, M; Leithe-Jasper, A; Tanaka, T; Shalamberidze, S O

    2010-02-01

    The discrepancy between Raman spectra of boron carbide obtained by Fourier transform Raman and conventional Raman spectrometry is systematically investigated. While at photon energies below the exciton energy (1.560 eV), Raman scattering of bulk phonons of boron carbide occurs, photon energies exceeding the fundamental absorption edge (2.09 eV) evoke additional patterns, which may essentially be attributed to luminescence or to the excitation of Raman-active processes in the surface region. The reason for this is the very high fundamental absorption in boron carbide inducing a very small penetration depth of the exciting laser radiation. Raman excitations essentially restricted to the boron carbide surface region yield spectra which considerably differ from bulk phonon ones, thus indicating structural modifications.

  4. Changes in biologically active ultraviolet radiation reaching the Earth's surface.

    PubMed

    McKenzie, Richard L; Björn, Lars Olof; Bais, Alkiviadis; Ilyasad, Mohammad

    2003-01-01

    Since publication of the 1998 UNEP Assessment, there has been continued rapid expansion of the literature on UV-B radiation. Many measurements have demonstrated the inverse relationship between column ozone amount and UV radiation, and in a few cases long-term increases due to ozone decreases have been identified. The quantity, quality and availability of ground-based UV measurements relevant to assessing the environmental impacts of ozone changes continue to improve. Recent studies have contributed to delineating regional and temporal differences due to aerosols, clouds, and ozone. Improvements in radiative transfer modelling capability now enable more accurate characterization of clouds, snow-cover, and topographical effects. A standardized scale for reporting UV to the public has gained wide acceptance. There has been increased use of satellite data to estimate geographic variability and trends in UV. Progress has been made in assessing the utility of satellite retrievals of UV radiation by comparison with measurements at the Earth's surface. Global climatologies of UV radiation are now available on the Internet. Anthropogenic aerosols play a more important role in attenuating UV irradiances than has been assumed previously, and this will have implications for the accuracy of UV retrievals from satellite data. Progress has been made inferring historical levels of UV radiation using measurements of ozone (from satellites or from ground-based networks) in conjunction with measurements of total solar radiation obtained from extensive meteorological networks. We cannot yet be sure whether global ozone has reached a minimum. Atmospheric chlorine concentrations are beginning to decrease. However, bromine concentrations are still increasing. While these halogen concentrations remain high, the ozone layer remains vulnerable to further depletion from events such as volcanic eruptions that inject material into the stratosphere. Interactions between global warming and

  5. Changes in biologically active ultraviolet radiation reaching the Earth's surface.

    PubMed

    McKenzie, Richard L; Björn, Lars Olof; Bais, Alkiviadis; Ilyasad, Mohammad

    2003-01-01

    Since publication of the 1998 UNEP Assessment, there has been continued rapid expansion of the literature on UV-B radiation. Many measurements have demonstrated the inverse relationship between column ozone amount and UV radiation, and in a few cases long-term increases due to ozone decreases have been identified. The quantity, quality and availability of ground-based UV measurements relevant to assessing the environmental impacts of ozone changes continue to improve. Recent studies have contributed to delineating regional and temporal differences due to aerosols, clouds, and ozone. Improvements in radiative transfer modelling capability now enable more accurate characterization of clouds, snow-cover, and topographical effects. A standardized scale for reporting UV to the public has gained wide acceptance. There has been increased use of satellite data to estimate geographic variability and trends in UV. Progress has been made in assessing the utility of satellite retrievals of UV radiation by comparison with measurements at the Earth's surface. Global climatologies of UV radiation are now available on the Internet. Anthropogenic aerosols play a more important role in attenuating UV irradiances than has been assumed previously, and this will have implications for the accuracy of UV retrievals from satellite data. Progress has been made inferring historical levels of UV radiation using measurements of ozone (from satellites or from ground-based networks) in conjunction with measurements of total solar radiation obtained from extensive meteorological networks. We cannot yet be sure whether global ozone has reached a minimum. Atmospheric chlorine concentrations are beginning to decrease. However, bromine concentrations are still increasing. While these halogen concentrations remain high, the ozone layer remains vulnerable to further depletion from events such as volcanic eruptions that inject material into the stratosphere. Interactions between global warming and

  6. Focused terahertz radiation formed by coherently scattered surface plasmon polaritons from partially uncorrugated metal surfaces

    NASA Astrophysics Data System (ADS)

    Monnai, Y.; Shinoda, H.; Hillmer, H.

    2011-09-01

    We present that a focus of terahertz radiation can be tailored based on coherent scattering of surface plasmon polaritons (SPPs) from a partially defected metal corrugation based on numerical simulations. The introduction of teeth defects in the corrugation allows coupling of the guided SPPs with the radiation and the far-field behavior is tailored by the spatial arrangement of such defects. The proposed structures serve as a kind of planar lenses which are quite thin and inexpensive. Promising applications include interfacing lens antennas between terahertz plasmonic integrated circuits and the external free space, which make terahertz systems very compact and low-cost.

  7. Urban Surface Radiative Energy Budgets Determined Using Aircraft Scanner Data

    NASA Technical Reports Server (NTRS)

    Luvall, Jeffrey C.; Quattrochi, Dale A.; Rickman, Doug L.; Estes, Maury G.; Arnold, James E. (Technical Monitor)

    2002-01-01

    the surface energy budget. Knowledge of it is important in any attempt to describe the radiative and mass fluxes which occur at the surface. Use of energy terms in modeling surface energy budgets allows the direct comparison of various land surfaces encountered in a urban landscape, from vegetated (forest and herbaceous) to non-vegetated (bare soil, roads, and buildings). These terms are also easily measured using remote sensing from aircraft or satellite platforms allowing one to examine the spacial variability. The partitioning of energy budget terms depends on the surface type. In natural landscapes, the partitioning is dependent on canopy biomass, leaf area index, aerodynamic roughness, and moisture status, all of which are influenced by the development stage of the ecosystem. In urban landscapes, coverage by man-made materials substantially alters the surface face energy budget. The remotely sensed data obtained from aircraft and satellites, when properly calibrated allows the measurement of important terms in the radiative surface energy budget a urban landscape scale.

  8. Niche and host-associated functional signatures of the root surface microbiome.

    PubMed

    Ofek-Lalzar, Maya; Sela, Noa; Goldman-Voronov, Milana; Green, Stefan J; Hadar, Yitzhak; Minz, Dror

    2014-01-01

    Plant microbiomes are critical to host adaptation and impact plant productivity and health. Root-associated microbiomes vary by soil and host genotype, but the contribution of these factors to community structure and metabolic potential has not been fully addressed. Here we characterize root microbial communities of two disparate agricultural crops grown in the same natural soil in a controlled and replicated experimental system. Metagenomic (genetic potential) analysis identifies a core set of functional genes associated with root colonization in both plant hosts, and metatranscriptomic (functional expression) analysis revealed that most genes enriched in the root zones are expressed. Root colonization requires multiple functional capabilities, and these capabilities are enriched at the community level. Differences between the root-associated microbial communities from different plants are observed at the genus or species level, and are related to root-zone environmental factors. PMID:25232638

  9. Niche and host-associated functional signatures of the root surface microbiome.

    PubMed

    Ofek-Lalzar, Maya; Sela, Noa; Goldman-Voronov, Milana; Green, Stefan J; Hadar, Yitzhak; Minz, Dror

    2014-09-18

    Plant microbiomes are critical to host adaptation and impact plant productivity and health. Root-associated microbiomes vary by soil and host genotype, but the contribution of these factors to community structure and metabolic potential has not been fully addressed. Here we characterize root microbial communities of two disparate agricultural crops grown in the same natural soil in a controlled and replicated experimental system. Metagenomic (genetic potential) analysis identifies a core set of functional genes associated with root colonization in both plant hosts, and metatranscriptomic (functional expression) analysis revealed that most genes enriched in the root zones are expressed. Root colonization requires multiple functional capabilities, and these capabilities are enriched at the community level. Differences between the root-associated microbial communities from different plants are observed at the genus or species level, and are related to root-zone environmental factors.

  10. Projections onto the Pareto surface in multicriteria radiation therapy optimization

    SciTech Connect

    Bokrantz, Rasmus E-mail: rasmus.bokrantz@raysearchlabs.com; Miettinen, Kaisa

    2015-10-15

    Purpose: To eliminate or reduce the error to Pareto optimality that arises in Pareto surface navigation when the Pareto surface is approximated by a small number of plans. Methods: The authors propose to project the navigated plan onto the Pareto surface as a postprocessing step to the navigation. The projection attempts to find a Pareto optimal plan that is at least as good as or better than the initial navigated plan with respect to all objective functions. An augmented form of projection is also suggested where dose–volume histogram constraints are used to prevent that the projection causes a violation of some clinical goal. The projections were evaluated with respect to planning for intensity modulated radiation therapy delivered by step-and-shoot and sliding window and spot-scanned intensity modulated proton therapy. Retrospective plans were generated for a prostate and a head and neck case. Results: The projections led to improved dose conformity and better sparing of organs at risk (OARs) for all three delivery techniques and both patient cases. The mean dose to OARs decreased by 3.1 Gy on average for the unconstrained form of the projection and by 2.0 Gy on average when dose–volume histogram constraints were used. No consistent improvements in target homogeneity were observed. Conclusions: There are situations when Pareto navigation leaves room for improvement in OAR sparing and dose conformity, for example, if the approximation of the Pareto surface is coarse or the problem formulation has too permissive constraints. A projection onto the Pareto surface can identify an inaccurate Pareto surface representation and, if necessary, improve the quality of the navigated plan.

  11. [The radiation-increased synthesis of phytochelatins in roots of gamma-irradiated barley seedlings].

    PubMed

    Danilin, I A; Dikarev, V G; Geras'kin, S A

    2004-01-01

    It was shown that gamma-irradiation and cadmium nitrate increased synthesis of phytochelatins in roots of barley seedlings. The stimulation of synthesis of phytochelatins in gamma-irradiated plants was shown for the first time. The results obtained indicate more important role of phytochelatins in intercellular metabolism than heavy-metal-binding.

  12. Radiation induced chemical activity at iron and copper oxide surfaces

    NASA Astrophysics Data System (ADS)

    Reiff, Sarah C.

    The radiolysis of three iron oxides, two copper oxides, and aluminum oxide with varying amounts of water were performed using gamma-rays and 5 MeV 4He ions. The adsorbed water on the surfaces was characterized using temperature programmed desorption and diffuse reflectance infrared spectroscopy, which indicated that all of the oxides had chemisorbed water on the surface. Physisorbed water was observed on the Fe2O 3 and Al2O3 surfaces as well. Molecular hydrogen was produced from adsorbed water only on Fe2O3 and Al 2O3, while the other compounds did not show any hydrogen production due to the low amounts of water on the surfaces. Slurries of varying amounts of water were also examined for hydrogen production, and they showed yields that were greater than the yield for bulk water. However, the yields of hydrogen from the copper compounds were much lower than those of the iron suggesting that the copper oxides are relatively inert to radiation induced damage to nearby water. X-ray diffraction measurements did not show any indication of changes to the bulk crystal structure due to radiolysis for any of the oxides. The surfaces of the oxides were analyzed using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). For the iron samples, FeO and Fe3O4, Raman spectroscopy revealed areas of Fe2O3 had formed following irradiation with He ions. XPS indicated the formation of a new oxygen species on the iron oxide surfaces. Raman spectroscopy of the copper oxides did not reveal any changes in the surface composition, however, XPS measurements showed a decrease in the amount of OH groups on the surface of Cu2O, while for the CuO samples the amount of OH groups were found to increase following radiolysis. Pristine Al2O3 showed the presence of a surface oxyhydroxide layer which was observed to decrease following radiolysis, consistent with the formation of molecular hydrogen.

  13. Grey-body surface radiation coupled with conduction and convection for general geometries

    NASA Astrophysics Data System (ADS)

    Engelman, Michael; Jamnia, Mohammad-Ali

    1991-11-01

    This paper presents a numerical technique for the simulation of the effects of grey-diffuse surface radiation on the temperature field of fluid flows using FIDAP, a general purpose incompressible, viscous fluid code. The radiating surface relationships assume a non-participating medium, constant surface temperature and heat fluxes at the discretized elemental level. The technique involves the decoupling of energy and radiation exchange equations. A concept of macrosurfaces, each containing a number of radiating boundary surfaces, is introduced. These boundary macroelements then carry the information from the radiating boundary into the fluid regime. A number of simulations illustrating the algorithm are presented.

  14. Numerical solution of fluid flow and heat tranfer problems with surface radiation

    NASA Technical Reports Server (NTRS)

    Ahuja, S.; Bhatia, K.

    1995-01-01

    This paper presents a numerical scheme, based on the finite element method, to solve strongly coupled fluid flow and heat transfer problems. The surface radiation effect for gray, diffuse and isothermal surfaces is considered. A procedure for obtaining the view factors between the radiating surfaces is discussed. The overall solution strategy is verified by comparing the available results with those obtained using this approach. An analysis of a thermosyphon is undertaken and the effect of considering the surface radiation is clearly explained.

  15. Measurement of Bremsstrahlung radiation for in vivo monitoring of 14C tracer distribution between fruit and roots of kiwifruit (Actinidia arguta) cuttings.

    PubMed

    Black, Marykate Z; Minchin, Peter E H; Gould, Nick; Patterson, Kevin J; Clearwater, Michael J

    2012-10-01

    In vivo measurements of (14)C tracer distribution have usually involved monitoring the β(-) particles produced as (14)C decays. These particles are only detectable over short distances, limiting the use of this technique to thin plant material. In the present experiments, X-ray detectors were used to monitor the Bremsstrahlung radiation emitted since β(-) particles were absorbed in plant tissues. Bremsstrahlung radiation is detectable through larger tissue depths. The aim of these experiments was to demonstrate the Bremsstrahlung method by monitoring in vivo tracer-labelled photosynthate partitioning in small kiwifruit (Actinidia arguta (Siebold & Zucc.) Planch. ex Miq.) plants in response to root pruning. A source shoot, consisting of four leaves, was pulse labelled with (14)CO(2). Detectors monitored import into a fruit and the root system, and export from a source leaf. Repeat pulse labelling enabled the comparison of pre- and post-treatment observations within an individual plant. Diurnal trends were observed in the distribution of tracer, with leaf export reduced at night. Tracer accumulated in the roots declined after approximately 48 h, which may have resulted from export of (14)C from the roots in carbon skeletons. Cutting off half the roots did not affect tracer distribution to the remaining half. Tracer distribution to the fruit was increased after root pruning, demonstrating the higher competitive strength of the fruit than the roots for carbohydrate supply. Increased partitioning to the fruit following root pruning has also been demonstrated in kiwifruit field trials.

  16. Near-polytropic stellar simulations with a radiative surface

    NASA Astrophysics Data System (ADS)

    Barekat, A.; Brandenburg, A.

    2014-11-01

    Context. Studies of solar and stellar convection often employ simple polytropic setups using the diffusion approximation instead of solving the proper radiative transfer equation. This allows one to control separately the polytropic index of the hydrostatic reference solution, the temperature contrast between top and bottom, and the Rayleigh and Péclet numbers. Aims: Here we extend such studies by including radiative transfer in the gray approximation using a Kramers-like opacity with freely adjustable coefficients. We study the properties of such models and compare them with results from the diffusion approximation. Methods: We use the Pencil code, which is a high-order finite difference code where radiation is treated using the method of long characteristics. The source function is given by the Planck function. The opacity is written as κ = κ0ρaTb, where a = 1 in most cases, b is varied from -3.5 to + 5, and κ0 is varied by four orders of magnitude. We adopt a perfect monatomic gas. We consider sets of one-dimensional models and perform a comparison with the diffusion approximation in one- and two-dimensional models. Results: Except for the case where b = 5, we find one-dimensional hydrostatic equilibria with a nearly polytropic stratification and a polytropic index close to n = (3 - b)/(1 + a), covering both convectively stable (n> 3/2) and unstable (n< 3/2) cases. For b = 3 and a = -1, the value of n is undefined a priori and the actual value of n depends then on the depth of the domain. For large values of κ0, the thermal adjustment time becomes long, the Péclet and Rayleigh numbers become large, and the temperature contrast increases and is thus no longer an independent input parameter, unless the Stefan-Boltzmann constant is considered adjustable. Conclusions: Proper radiative transfer with Kramers-like opacities provides a useful tool for studying stratified layers with a radiative surface in ways that are more physical than what is possible with

  17. Can radiation therapy treatment planning system accurately predict surface doses in postmastectomy radiation therapy patients?

    SciTech Connect

    Wong, Sharon; Back, Michael; Tan, Poh Wee; Lee, Khai Mun; Baggarley, Shaun; Lu, Jaide Jay

    2012-07-01

    Skin doses have been an important factor in the dose prescription for breast radiotherapy. Recent advances in radiotherapy treatment techniques, such as intensity-modulated radiation therapy (IMRT) and new treatment schemes such as hypofractionated breast therapy have made the precise determination of the surface dose necessary. Detailed information of the dose at various depths of the skin is also critical in designing new treatment strategies. The purpose of this work was to assess the accuracy of surface dose calculation by a clinically used treatment planning system and those measured by thermoluminescence dosimeters (TLDs) in a customized chest wall phantom. This study involved the construction of a chest wall phantom for skin dose assessment. Seven TLDs were distributed throughout each right chest wall phantom to give adequate representation of measured radiation doses. Point doses from the CMS Xio Registered-Sign treatment planning system (TPS) were calculated for each relevant TLD positions and results correlated. There were no significant difference between measured absorbed dose by TLD and calculated doses by the TPS (p > 0.05 (1-tailed). Dose accuracy of up to 2.21% was found. The deviations from the calculated absorbed doses were overall larger (3.4%) when wedges and bolus were used. 3D radiotherapy TPS is a useful and accurate tool to assess the accuracy of surface dose. Our studies have shown that radiation treatment accuracy expressed as a comparison between calculated doses (by TPS) and measured doses (by TLD dosimetry) can be accurately predicted for tangential treatment of the chest wall after mastectomy.

  18. Comparison of Surface Radiation Budget Satellite algorithms for downwelled shortwave irradiance with Wisconsin Fire/SRB surface-truth data

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Staylor, W. F.; Darnell, W. L.; Chou, M. D.; Dedieu, G.; Deschamps, P. Y.; Ellis, J.; Gautier, C.; Frouin, R.; Rossow, W. B.

    1990-01-01

    Surface radiation instruments were operated at various locations during the Wisconsin First ISSCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE) and Surface Radiation Budget (SRB) experiment in October 1986. Satellite data were distributed to scientists who had previously developed satellite algorithms to estimate downwelled shortwave irradiance. Results of intercomparison of ground-truth values with the satellite-derived estimates are described.

  19. Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces

    NASA Technical Reports Server (NTRS)

    Rutherford, R.; Gallois, P.; Masson, P. H.

    1998-01-01

    Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes of trp5-2wvc1, trp2-1 and trp3-1 seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole, trp5-2wvc1 mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.

  20. Effect of Citric Acid and Ethylenediaminetetraacetic Acid on the Surface Morphology of Young and Old Root Dentin

    PubMed Central

    Scelza, Miriam Zaccaro; de Noronha, Fernando; da Silva, Licinio Esmeraldo; Maurício, Marcos; Gallito, Marco Antonio; Scelza, Pantaleo

    2016-01-01

    Introduction: The aim of this in vitro study was to evaluate the effect of 10% citric acid and 17% ethylenediaminetetraacetic acid (EDTA) irrigating solutions on the surface morphology of young and old root dentin by determining the number and diameter of dentinal tubules using scanning electron microscopy (SEM). Methods and Materials: Fifty healthy human teeth collected from young (≤30 years) and old (≥60 years) individuals (n=25) were first prepared with a Largo bur #2 to produce smear layer on the root canal surface. Subsequently, the crowns and the root middle and apical thirds were sectioned and removed, and the cervical thirds were sectioned vertically in the buccal-lingual direction into two equal halves. The obtained samples were then immersed in 2.5% sodium hypochlorite for 30 min and randomly separated into two treatment groups for each age group. In each age group, ten samples were selected as controls and did not receive any type of treatment. The rest of the specimens were then rinsed, dried and treated for 4 min with 10% citric acid or 17% EDTA. The samples were then assessed with SEM regarding the number and diameter of dentinal tubules. All data were assessed using Student’s t-test. The level of significance was set at 0.05. Results: Regardless of the type of treatment, no significant differences were observed in the number of open tubules between the young and old root dentin (P>0.05). Nonetheless, the diameter of the tubules in the old root dentin was larger when 17% EDTA was used (P<0.05). Both, young and old root dentin did not differ with the 10% citric acid treatment (P>0.05). Conclusion: The results showed that 17% EDTA treatment induced a significant demineralization in old root dentin. PMID:27471529

  1. DELAYED TOOTH REPLANTATION AFTER ROOT SURFACE TREATMENT WITH SODIUM HYPOCHLORITE AND SODIUM FLUORIDE: HISTOMORPHOMETRIC ANALYSIS IN RATS

    PubMed Central

    Sottovia, André Dotto; Sonoda, Celso Koogi; Poi, Wilson Roberto; Panzarini, Sônia Regina; Lauris, José Roberto Pereira

    2006-01-01

    In cases of delayed tooth replantation, non-vital periodontal ligament remnants have been removed with sodium hypochlorite in an attempt to control root resorption. Nevertheless, reports of its irritating potential in contact with the alveolar connective tissue have been described. Therefore, this study evaluated the healing process on delayed replantation of rat teeth, after periodontal ligament removal by different treatment modalities. Twenty-four rats, assigned to 3 groups (n=8), had their upper right incisor extracted and left on the workbench for desiccation during 60 min. Afterwards, the teeth in group I were immersed in saline for 2 min. In group II, root surfaces were scrubbed with gauze soaked in saline for 2 min; and in group III, scrubbing was done with gauze soaked in 1% sodium hypochlorite solution. Thereafter, root surfaces were etched with 37% phosphoric acid and immersed in 2% acidulate-phosphate sodium fluoride solution, at pH 5.5. Root canals were filled with a calcium hydroxide-based paste and the teeth were replanted. The animals were sacrificed 60 days postoperatively and the pieces containing the replanted teeth were processed and paraffin-embedded. Semi-serial transversally sections were obtained from the middle third of the root and stained with hematoxylin and eosin for histomorphometric analysis. Data were analyzed statistically using Kruskal-Wallis and Dunn's tests. The results showed that root structure and cementum extension were more affected by resorption in group III (p<0.05). All groups were affected by root resorption but the treatment performed in group III was the least effective for its control. The treatment accomplished in groups I and II yielded similar results to each other. PMID:19089038

  2. Sensor intercomparison of distributed surface radiation measurement system

    NASA Astrophysics Data System (ADS)

    Dou, Baocheng; Wen, Jianguang; Li, Xiuhong; Liu, Qiang; Xiao, Qing; Bai, Junhua; Peng, Jingjing; Lin, Xingwen; Zhang, Zhigang; Wu, Xiaodan; Cai, Erli; Zhang, Jialin; Chang, Chongyan

    2015-12-01

    The Wireless Sensor Networks of Coarse-resolution Pixel Parameters (CPP-WSN) was established to monitor the heterogeneity of coarse spatial resolution pixel, with consideration of different categories of land surface parameters in Huailai, Hebei province, China (40.349°N, 115.785°E). The observation network of radiation parameters (RadNet) in CPP-WSN was developed for multi-band radiation measurement and consisted of 6 nodes covering 2km*2km area to capture its heterogeneity. Each node employed four sensors to observe the five radiation parameters. The number and location of nodes in RadNet were determined through the representativeness-based sampling method. Thus, the RadNet is a distributed observation system with nodes work synchronously and measurements used together. The intercomparison experiment for RadNet is necessary and was conducted in Huailai Remote Sensing Station from 5th Aug to 10th Aug in 2012. Time series observations from various sensors were collected and analyzed. The maximum relative differences among sensors of UVR, SWR, LWR, PAR, and LST are 4.83%, 5.3%, 3.71%, 11%, and 0.54%, respectively. Sensor/parameter differences indeed exist and are considerable large for PAR, SWR, UVR, and LWR, which cannot be ignored. The linear normalization and quadratic polynomial normalization perform similar for CUV5/UVR, PQS1/PAR, CNR4/SWR, and SI-111/LST. As for CNR4/LWR, quadratic polynomial normalization show higher accuracy than linear normalization, especially in node2, node4, and node5. Thus, the LWR measured by CNR4 is proved to be nonlinear, and should be normalized with quadratic polynomial coefficients for higher precision.

  3. Calibration facilities for borehole and surface environmental radiation measurements

    SciTech Connect

    Stromswold, D.C.

    1994-04-01

    Measuring radiation from contaminated soil and buildings is important in the cleanup of land areas and facilities. It provides the means for quantifying the amount of contamination and assessing the success of efforts to restore areas to acceptable conditions for public use. Instruments that measure in situ radiation from natural or radiochemically-contaminated earth formations must be calibrated in appropriate facilities to provide quantitative assessments of concentrations of radionuclides. For instruments that are inserted into boreholes, these calibration facilities are typically special models having holes for probe insertion and having sufficient size to appear radiometrically ``infinite`` in extent. The US Department of Energy (DOE) has such models at Hanford, Washington, and Grand Junction, Colorado. They are concrete cylinders having a central borehole and containing known, enhanced amounts of K, U, and Th for spectral gamma-ray measurements. Additional models contain U for calibrating neutron probes for fissile materials and total-count gamma-ray probes. Models for calibrating neutron probes for moisture measurements in unsaturated formations exist for steel-cased boreholes at Hanford and for uncased boreholes at the DOE`s Nevada Test Site. Large surface pads are available at Grand Junction for portable, vehicle-mounted, or airplane-mounted spectral gamma-ray detectors.

  4. Formation of micron and submicron structures on a zirconium oxide surface exposed to nanosecond laser radiation

    SciTech Connect

    Ganin, D V; Mikolutskiy, S I; Khomich, V Yu; Yamshchikov, V A; Tokarev, V N; Shmakov, V A

    2014-04-28

    Possibility of forming quasi-periodic structures of micron and submicron dimensions on a surface of zirconium dioxide under the action of eximer ArF laser radiation is shown experimentally and theoretically. (interaction of laser radiation with matter)

  5. Do satellites detect trends in surface solar radiation?

    PubMed

    Pinker, R T; Zhang, B; Dutton, E G

    2005-05-01

    Long-term variations in solar radiation at Earth's surface (S) can affect our climate, the hydrological cycle, plant photosynthesis, and solar power. Sustained decreases in S have been widely reported from about the year 1960 to 1990. Here we present an estimate of global temporal variations in S by using the longest available satellite record. We observed an overall increase in S from 1983 to 2001 at a rate of 0.16 watts per square meter (0.10%) per year; this change is a combination of a decrease until about 1990, followed by a sustained increase. The global-scale findings are consistent with recent independent satellite observations but differ in sign and magnitude from previously reported ground observations. Unlike ground stations, satellites can uniformly sample the entire globe. PMID:15879215

  6. Aerosol and its Radiative Impact on Surface Solar Radiation in China

    NASA Astrophysics Data System (ADS)

    Li, Z.

    2007-05-01

    As a fast developing country covering a large territory, China is experiencing rapid environmental changes. High concentrations of aerosols with diverse properties are emitted in the region, providing a unique opportunity for understanding the impact of environmental changes on climate. Until very recently, few observational studies were conducted in this important source regions. The East Asian Study of Tropospheric Aerosols: an International Regional Experiment (EAST-AIRE) attempts to characterize the physical, optical and chemical properties of the aerosols and their effects on climate over China. Some preliminary results will be presented using continuous high-quality measurements of aerosol, cloud and radiative quantities made at the EAST-AIRE baseline stations in northern and southern China. Both regions are often covered by a thick layer of haze (with a yearly mean aerosol optical depth 0.7-0.8) due primarily to anthropogenic emissions of moderately strong absorbing aerosols, leading exceptionally large aerosol radiative effect at the surface in broadband, PAR and ultraviolet radiation. The boundary atmosphere is thus heated dramatically during the daytime, which may affect atmospheric stability and cloud formation.

  7. Healing of periodontal defects treated with enamel matrix proteins and root surface conditioning--an experimental study in dogs.

    PubMed

    Sakallioğlu, Umur; Açikgöz, Gökhan; Ayas, Bülent; Kirtiloğlu, Tuğrul; Sakallioğlu, Eser

    2004-05-01

    Application of enamel matrix proteins has been introduced as an alternative method for periodontal regenerative therapy. It is claimed that this approach provides periodontal regeneration by a biological approach, i.e. creating a matrix on the root surfaces that promotes cementum, periodontal ligament (PDL) and alveolar bone regeneration, thus mimicking the events occurring during tooth development. Although there have been numerous in vitro and in vivo studies demonstrating periodontal regeneration, acellular cementum formation and clinical outcomes via enamel matrix proteins usage, their effects on the healing pattern of soft and hard periodontal tissues are not well-established and compared with root conditioning alone. In the present study, the effects of Emdogain (Biora, Malmö, Sweden), an enamel matrix derivative mainly composed of enamel matrix proteins (test), on periodontal wound healing were evaluated and compared with root surface conditioning (performed with 36% orthophosphoric acid) alone (control) histopathologically and histomorphometrically by means of the soft and hard tissue profile of periodontium. An experimental periodontitis model performed at premolar teeth of four dogs were used in the study and the healing pattern of periodontal tissues was evaluated at days 7, 14, 21, 28 (one dog at each day), respectively. At day 7, soft tissue attachment evaluated by means of connective tissue and/or epithelial attachment to the root surfaces revealed higher connective tissue attachment rate in the test group and the amount of new connective tissue proliferation in the test group was significantly greater than the control group (p<0.01). New bone formation by osteoconduction initiated at day 14 in the test and control group. At day 21, the orientation of supra-alveolar and PDL fibers established, and new cementum formation observed in both groups. At day 28, although regenerated cementum was cellular in all of the roots in the control samples, an

  8. Filimonas endophytica sp. nov., isolated from surface-sterilized root of Cosmos bipinnatus.

    PubMed

    Han, Ji-Hye; Kim, Tae-Su; Joung, Yochan; Kim, Seung Bum

    2015-12-01

    A Gram-stain-negative, yellow, motile by gliding, filamentous bacterium, designated SR 2-06T, was isolated from surface-sterilized root of garden cosmos. 16S rRNA gene sequence analysis indicated that SR 2-06T was related most closely to Filimonas lacunae YT21T of the family Chitinophagaceae at a sequence similarity of 96.90 %, while levels of similarity to other related taxa were less than 93.08 %. Strain SR 2-06T exhibited similar features to F. lacunae in that it contained MK-7 as the major respiratory quinone, and iso-C15 : 1 G, iso-C15 : 0 and a summed feature consisting of C16 : 1ω6c and/or C16 : 1ω7c as the major fatty acids. However, strain SR 2-06T was distinguished from F. lacunae using a combination of physiological and biochemical properties. The cellular polar lipids were phosphatidylethanolamine, unknown aminophospholipids, unknown aminolipids, an unknown phospholipid and unidentified polar lipids. The DNA G+C content was 46.0 mol%. The phenotypic and phylogenetic evidence clearly indicates that strain SR 2-06T represents a novel species of the genus Filimonas, for which the name Filimonas endophytica sp. nov. is proposed. The type strain is SR 2-06T ( = KCTC 42060T = JCM 19844T).

  9. Tunable surface plasmon instability leading to emission of radiation

    SciTech Connect

    Gumbs, Godfrey; Iurov, Andrii; Huang, Danhong; Pan, Wei

    2015-08-07

    We propose a new approach for energy conversion from a dc electric field to tunable terahertz emission based on hybrid semiconductors by combining two-dimensional (2D) crystalline layers and a thick conducting material with possible applications for chemical analysis, security scanning, medical (single-molecule) imaging, and telecommunications. The hybrid nano-structure may consist of a single or pair of sheets of graphene, silicene, or a 2D electron gas. When an electric current is passed through a 2D layer, we discover that two low-energy plasmon branches exhibit a characteristic loop in their dispersion before they merge into an unstable region beyond a critical wave vector q{sub c}. This finite q{sub c} gives rise to a wavenumber cutoff in the emission dispersion of the surface plasmon induced instability and emission of radiation (spiler). However, there is no instability for a single driven layer far from the conductor, and the instability of an isolated pair of 2D layers occurs without a wavenumber cutoff. The wavenumber cutoff is found to depend on the conductor electron density, layer separation, distances of layers from the conductor surface, and the driving-current strength.

  10. Estimating photosynthetically available radiation at the ocean surface from GOCI data

    NASA Astrophysics Data System (ADS)

    Frouin, Robert; McPherson, John

    2012-09-01

    A technique is presented to estimate photosynthetically available radiation (PAR) at the ocean surface from Geostationary Ocean Color Imager (GOCI) data. The sensor is adapted to the problem, since it measures at visible wavelengths and does not saturate over clouds, and the hourly data provides adequate temporal sampling to describe diurnal variability of clouds. Instantaneous surface PAR is computed as the difference between the solar irradiance incident at the top of the atmosphere (known) and the solar irradiance reflected back to space (derived from GOCI radiance), taking into account absorption and scattering by the clear atmosphere (modeled). Knowledge of pixel composition is not required. Apart from planetary albedo and sun zenith angle, the model parameters are fixed at their climatological values. The instantaneous PAR estimates at hourly intervals are integrated over time to provide daily values. The technique is applied to GOCI imagery acquired on 5 April 2011, and the GOCI daily PAR estimates are compared with those obtained from MODerate Resolution Imaging Spectrometer (MODIS) data. Agreement is good between the two types of estimates, with a coefficient of determination ( r 2) of 0.778, a bias of 0.23 Em-2d-1 (0.5% with higher GOCI values), and a root-mean-squared difference of 5.00 Em-2d-1 (11.2%). Differences in cloudy conditions are attributed to daily cloudiness changes not captured by the MODIS observations. The comparison statistics indicate that GOCI PAR estimates have acceptable accuracy for regional studies of aquatic photosynthesis.

  11. SYRA3 COST Action--Microbeam radiation therapy: Roots and prospects.

    PubMed

    Bravin, Alberto; Olko, Pawel; Schültke, Elisabeth; Wilkens, Jan J

    2015-09-01

    Microbeam radiation therapy (MRT) is an irradiation modality for therapeutic purposes which uses arrays of collimated quasi parallel microbeams, each up to 100 μm wide, to deliver high radiation doses. Several studies have reported the extraordinary tolerance of normal tissues to MRT irradiation; conversely, MRT has been shown to be highly efficient on tumor growth control. The original and most widely developed application of MRT, yet in the preclinical phase, consists in using spatially fractionated X-ray beams issued from a synchrotron radiation source in the treatment of brain tumors. More recently, MRT has been tested in successful pioneering assays to reduce or interrupt seizures in preclinical models of epilepsy. The MRT concept has also been extended to proton therapy. The development of MRT towards its clinical implementation is presently driven by an EU-supported consortium of laboratories from 16 countries within the COST Action TD1205 (SYRA3). The results of the first SYRA3 workshop on "Radiation Therapy with Synchrotron Radiation: Achievements and Challenges" held in Krakow (Poland) during March 25-26 2014 are summarized in this issue with an overview presented in this paper. The papers reflect the multidisciplinary international activities of SYRA3. The topics covered in this focus issue include medical physics aspects, pre-clinical studies, clinical applications, and an industrial perspective; finally an outlook towards future prospects of compact sources and proton microbeams. PMID:26123367

  12. Cloudy sky shortwave radiative closure for a Baseline Surface Radiation Network site

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Knap, Wouter H.; Stammes, Piet

    2011-04-01

    A shortwave radiative closure analysis for cloudy skies is presented for the Cabauw Baseline Surface Radiation Network (BSRN) site (51.97°N, 4.93°E). The cloudy cases are carefully selected to be overcast, single-layer, homogeneous, nonprecipitating water clouds. We selected in total 639 cases on 9 days between May 2008 and May 2009 and on 30 January 2007. The Doubling-Adding KNMI (DAK) code is used to simulate global irradiances. The cloud optical thickness is derived from the cloud liquid water path from microwave radiometer (MWR) measurements and the MODIS L2 cloud effective radius product. The scattering phase matrix of the cloud particles is calculated using a Mie code with the two-parameter Gamma size distribution. The MWR integrated water vapor column and an aerosol climatology are also used in the simulations. The cloudy cases cover a large range of liquid water path (30-400 g/m2), water vapor column (0.7-3.1 cm), and solar zenith angle (41°-75°). The mean difference between simulated global irradiances and BSRN measurements is 6 W/m2 (5%), with a standard deviation of 14 W/m2 (13%). This difference is within the uncertainties of the model input parameters and measurement errors. The correlation coefficient between the measured and simulated global irradiances is 0.95. The good closure results demonstrate the high quality of the MODIS effective radius data and MWR liquid water path data and the accuracy of the DAK model for the selected water cloud cases. Furthermore, the effects of clouds, aerosols, water vapor, and surface albedo on the global irradiance have been analyzed carefully. The sensitivity study shows that in order to achieve the closure with an uncertainty of a few W/m2, more frequent effective radius data, simultaneous aerosol and cloud measurements, and surface albedo measurements are essential.

  13. Mapping photosynthetically available radiation at the sea surface using GOCI

    NASA Astrophysics Data System (ADS)

    Choi, Jongkuk; Kim, Jihye; Yang, Hyun; Moon, Jeong-Eon; Frouin, Robert

    2016-04-01

    Photosynthetically available radiation (PAR) controls the composition of marine ecosystem by affecting the growth of phytoplankton, thus estimating PAR at the ocean surface accurately is important to understand the marine ecological environment. Although many studies have been attempted to estimate PAR employing ocean colour satellite data since 2003, previous studies using data from the polar orbit systems had spatial and temporal limitations to estimate accurate daily PAR. Here, we estimate daily PAR from Geostationary Ocean Colour Imager (GOCI) which collects data eight times a day at an hour interval in daytime and compare it with in-situ measurement and MODIS-based daily PAR. The algorithm we developed in this study, employed GOCI visible bands (centred at (412, 443, 490, 555, 660, 680 nm) which belongs to the range of PAR by calculating albedo at the layer of clouds and the sea surface to estimate daily PAR. The resultant value was validated by comparing the in-situ measurements acquired from an ocean research station, Socheongcho between February and May 2015, which showed a similar pattern with somewhat GOCI-base PAR's overestimations. The comparison with the results from MODIS, a polar orbit system showed that a good agreement with each other was illustrated at clear sky conditions, while MODIS showed some over- or underestimations at cloudy conditions with irregular patterns. This study shows that GOCI can estimate effectively the daily PAR with its advantages of acquiring data more frequently than other polar orbit ocean colour satellites by reducing the uncertainties induced by insufficient images to map the daily PAR at ocean surface.

  14. An In-Situ Root-Imaging System in the Context of Surface Detection of CO2

    NASA Astrophysics Data System (ADS)

    Apple, M. E.; Prince, J. B.; Bradley, A. R.; Zhou, X.; Lakkaraju, V. R.; Male, E. J.; Pickles, W.; Thordsen, J. J.; Dobeck, L.; Cunningham, A.; Spangler, L.

    2009-12-01

    Carbon sequestration is a valuable method of spatially confining CO2 belowground. The Zero Emissions Research Technology, (ZERT), site is an experimental facility in a former agricultural field on the Montana State University campus in Bozeman, Montana, where CO2 was experimentally released at a rate of 200kg/day in 2009 into a 100 meter underground injection well running parallel to the ground surface. This injection well, or pipe, has deliberate leaks at intervals, and CO2 travels from these leaks upward to the surface of the ground. The ZERT site is a model system designed with the purpose of testing methods of surface detection of CO2. One important aspect of surface detection is the determination of the effects of CO2 on the above and belowground portions of plants growing above sequestration fields. At ZERT, these plants consist of a pre-existing mixture of herbaceous species present at the agricultural field. Species growing at the ZERT site include several grasses, Dactylis glomerata (Orchard Grass), Poa pratensis (Kentucky Bluegrass), and Bromus japonicus (Japanese Brome); the nitrogen-fixing legumes Medicago sativa, (Alfalfa), and Lotus corniculatus, (Birdsfoot trefoil); and an abundance of Taraxacum officinale, (Dandelion). Although the aboveground parts of the plants at high CO2 are stressed, as indicated by changes in hyperspectral plant signatures, leaf fluorescence and leaf chlorophyll content, we are interested in determining whether the roots are also stressed. To do so, we are combining measurements of soil conductivity and soil moisture with root imaging. We are using an in-situ root-imaging system manufactured by CID, Inc. (Camas, WA), along with image analysis software (Image-J) to analyze morphometric parameters in the images and to determine what effects, if any, the presence of leaking and subsequently upwelling CO2 has on the phenology of root growth, growth and turnover of individual fine and coarse roots, branching patterns, and root

  15. Simultaneous decay of contact-angle and surface-tension during the rehydration of air-dried root mucilage

    NASA Astrophysics Data System (ADS)

    Arye, Gilboa; Chen, Fengxian

    2016-04-01

    Plants can extract or exude water and solutes at their root surface. Among the root exudates, the mucilage exhibits a surfactant like properties - depressing the surface-tension (ST, mN/m) at the water-air interface. The amphipathic nature of some of the mucilage molecules (e.g. lipids) is thought to be the reason for its surfactant like behavior. As the rhizosphere dries out, re-orientation and/or re-configuration of amphipathic molecules at the solid-air interface, may impart hydrophobic nature to the rhizosphere. Our current knowledge on the ST of natural and/or model root mucilage is based on measurements of the equilibrium ST. However, adsorption of amphipathic molecules at the water-air interface is not reached instantaneously. The hydrophobic nature of the rhizosphere was deduced from the initial advancing CA, commonly calculated from the first few milliseconds up to few seconds (depending on the method employed). We hypothesized that during the rehydration of the root mucilage; both quantities are dynamic. Processes such as water absorbance and dissolution, may vary the interfacial tensions as a function of time. Consequently, simultaneous reduction of both CA and ST as a function of time can be expected. The main objective of this study was to characterize and quantify the extent, persistency and dynamic of the CA and ST during rehydration of air-dried root mucilage. The study was involved with measurements of dynamic and equilibrium ST using the pedant drop or Wilhelmy plate method, respectively. Glass slides were coated with naturally occurring or model root mucilage and the CA of a sessile drop was measured optically, as a function of time. The results were analyzed based on the Young-Dupré and Young-Laplace equations, from which the simultaneous decay of CA and ST was deduced. The implication for the wettability and water flow in the rhizosphere will be discussed.

  16. Imaging crustal roots in the Europe-Mediterranean region: a surface wave perspective

    NASA Astrophysics Data System (ADS)

    Villaseñor, Antonio

    2016-04-01

    The thickness of crustal roots is a fundamental constrain to understand the geodynamic evolution of mountain ranges. Crustal thickness can be inferred from a variety of geophysical observables (e.g. gravity anomalies, active and passive seismic methods, etc). Deep seismic sounding (DSS) using controlled sources usually provides the most accurate images of the crustal structure and thickness. However it is an expensive method, and often only used for 2D profiles. On the other hand, passive seismology experiments based on earthquakes or ambient noise have generally lower resolution, but are cheaper to conduct and can provide 3D images. As a result of the success of USArray, experiments consisting of dense deployments of broadband seismometers have become the modern standard approach for imaging continental regions. This, in combination with the densification of permanent regional monitoring networks and the use of seismic ambient noise, has allowed to use surface waves to image with increased resolution regions such as Europe and the Mediterranean basin. Surface waves are not very sensitive to the location of discontinuities such as the Moho, but can provide good constraints on the lateral variation of crustal thickness. Here, by combining continuous recordings of array experiments and permanent networks, I present a new tomographic model of surface wave velocities in the Europe-Mediterranean region that can be used as a proxy for crustal thickness. Large low velocity anomalies corresponding to thick crust are observed as expected in mountain ranges such as the Atlas, Pyrenees and Alps where crustal thickening has occurred as a result of continental collision. In addition, similarly large low velocity anomalies are observed in regions where slab roll-back/break-off has occurred (Betic-Rif, NW and SE Carpathians, Apennines, western Balkan peninsula). While these anomalies might not all be originated by thick crust, in some cases such as the Rif-western Betics

  17. Auditory Evaluation of Sound Signals Radiated by a Vibrating Surface

    NASA Astrophysics Data System (ADS)

    MEUNIER, S.; HABAULT, D.; CANÉVET, G.

    2001-11-01

    This paper presents a combination of vibroacoustic and psychoacoustic studies of sounds radiated by a vibrating structure. The calculated sound field is the sound pressure radiated by a baffled thin-plate structure immersed in a fluid, on the surface of which the acceleration is given. Various configurations are selected for the time and space functions of the acceleration variable, each configuration leading to a particular acoustic signal (a low-frequency tone complex in our case). These signals are then transformed into sound files, which are used as test signals in psychoacoustic experiments for assessing their perceptual attributes and quality. Two experiments were run. In the first one, the unpleasantness of a series of signals at different levels was measured by direct estimation and compared with their calculated loudness and sharpness using Zwicker's model. The same measurements were repeated with the signals set to the same maximum amplitude. In the second experiment, the pleasantness of another series of sounds at equal loudness was measured, as well as dissimilarity and preference on pairs of these sounds. An MDS analysis was run to extract auditory attributes that could account for the perceived differences between sounds and correlate with the estimated pleasantness. The results from the first experiment show that pleasantness is always highly (and negatively) correlated with loudness. The same holds for sharpness, when sounds are played at the same maximum amplitude. The second experiment shows that the perceptual attributes revealed by the MDS analysis are related to pitch and timbre, the latter being highly correlated with pleasantness. Overall, this study confirms the interest of extending vibroacoustic studies to a more complete “psychomechanical” investigation of the whole process of sound generation. It is suggested that such investigations may apply to product sound quality and to active or passive noise control, by providing

  18. [Effect of iron plaque formation of root surface on as uptake by rice seedlings grown on different types of soils].

    PubMed

    Guo, Wei; Lin, Xian-yong; Cheng, Wang-da

    2010-02-01

    The objective of study was to investigate the effect of the amount of iron plaque of root surface on As uptake by rice seedlings grown on 14 types of soils. These results indicated that there were significant differences in the amounts of iron plaque (1.15-61.97 mg/g) formed on rice root surface among different soils. The amount of non-crystalloid Fe oxide in different submerged soils is one of main influencing factors. There was a significant positive correlation between As concentrations in iron plaque (0-1376 mg/kg) and the amount of iron plaque (r = 0.85, n=14, p < 0.05), but no significant correlation with the extractable As concentration of 14 types of soils. There were also significant positive correlation between As concentrations in shoot (0.400-12.98 mg/kg) and root (3.860-576.2 mg/kg) and the amounts of iron plaque respectively but not significant correlation with the extractable As concentrations of 14 types of soils (r = 0.88, n=14, p < 0.05; r = 0.91, n=14, p < 0.05). Moreover, there was a significant positive correlation between specific arsenic uptake (0.005-0.670 mg/g) and the amount of iron plaque (r = 0.91, n=14, p < 0.05). However, there was no significant correlation between shoot-As% and the amount of iron plaque. These results showed that the iron plaque on root surface was the pool of As in rhizosphere and increased As uptake but did not affect As transportation from rice root to shoot. PMID:20391723

  19. Improving satellite-retrieved surface radiative fluxes in polar regions using a smart sampling approach

    NASA Astrophysics Data System (ADS)

    Van Tricht, Kristof; Lhermitte, Stef; Gorodetskaya, Irina V.; van Lipzig, Nicole P. M.

    2016-10-01

    The surface energy budget (SEB) of polar regions is key to understanding the polar amplification of global climate change and its worldwide consequences. However, despite a growing network of ground-based automatic weather stations that measure the radiative components of the SEB, extensive areas remain where no ground-based observations are available. Satellite remote sensing has emerged as a potential solution to retrieve components of the SEB over remote areas, with radar and lidar aboard the CloudSat and CALIPSO satellites among the first to enable estimates of surface radiative long-wave (LW) and short-wave (SW) fluxes based on active cloud observations. However, due to the small swath footprints, combined with a return cycle of 16 days, questions arise as to how CloudSat and CALIPSO observations should be optimally sampled in order to retrieve representative fluxes for a given location. Here we present a smart sampling approach to retrieve downwelling surface radiative fluxes from CloudSat and CALIPSO observations for any given land-based point-of-interest (POI) in polar regions. The method comprises a spatial correction that allows the distance between the satellite footprint and the POI to be increased in order to raise the satellite sampling frequency. Sampling frequency is enhanced on average from only two unique satellite overpasses each month for limited-distance sampling < 10 km from the POI, to 35 satellite overpasses for the smart sampling approach. This reduces the root-mean-square errors on monthly mean flux estimates compared to ground-based measurements from 23 to 10 W m-2 (LW) and from 43 to 14 W m-2 (SW). The added value of the smart sampling approach is shown to be largest on finer temporal resolutions, where limited-distance sampling suffers from severely limited sampling frequencies. Finally, the methodology is illustrated for Pine Island Glacier (Antarctica) and the Greenland northern interior. Although few ground-based observations are

  20. Evaluation of root water uptake in the ISBA-A-gs land surface model using agricultural yield statistics over France

    NASA Astrophysics Data System (ADS)

    Canal, N.; Calvet, J.-C.; Decharme, B.; Carrer, D.; Lafont, S.; Pigeon, G.

    2014-12-01

    The simulation of root water uptake in land surface models is affected by large uncertainties. The difficulty in mapping soil depth and in describing the capacity of plants to develop a rooting system is a major obstacle to the simulation of the terrestrial water cycle and to the representation of the impacts of drought. In this study, long time series of agricultural statistics are used to evaluate and constrain root water uptake models. The inter-annual variability of cereal grain yield and permanent grassland dry matter yield is simulated over France by the Interactions between Soil, Biosphere and Atmosphere, CO2-reactive (ISBA-A-gs) generic land surface model (LSM). The two soil profile schemes available in the model are used to simulate the above-ground biomass (Bag) of cereals and grasslands: a two-layer force-restore (FR-2L) bulk reservoir model and a multi-layer diffusion (DIF) model. The DIF model is implemented with or without deep soil layers below the root zone. The evaluation of the various root water uptake models is achieved by using the French agricultural statistics of Agreste over the 1994-2010 period at 45 cropland and 48 grassland départements, for a range of rooting depths. The number of départements where the simulated annual maximum Bag presents a significant correlation with the yield observations is used as a metric to benchmark the root water uptake models. Significant correlations (p value < 0.01) are found for up to 29 and 77% of the départements for cereals and grasslands, respectively. A rather neutral impact of the most refined versions of the model is found with respect to the simplified soil hydrology scheme. This shows that efforts should be made in future studies to reduce other sources of uncertainty, e.g. by using a more detailed soil and root density profile description together with satellite vegetation products. It is found that modelling additional subroot-zone base flow soil layers does not improve (and may even degrade

  1. Changes in the size of the apparent surface area and adsorption energy of the rye roots by low pH and the presence of aluminium ions induced

    NASA Astrophysics Data System (ADS)

    Szatanik-Kloc, Alicja

    2016-07-01

    The plant reactions on Al-stress include i.a. change of the surface area of the roots, which in the physicochemistry of plants characterizes the transport of water and ions through the root. The object of this study is the specific surface area of the roots of plants which are tolerant to aluminium, such as rye. Plants of rye were grown in a nutrient solution for 14 days at pH 4.5 in the presence of Al3+ ions of concentration 10, 20, and 40 mg dm-3. The control plants were grown continuously at pH 7 or pH 4.5 without Al3+. The apparent surface area and adsorption energy of the plants roots were determined from water vapour adsorption - desorption data. The apparent surface area of roots growing in the aluminium was (with respect to control) statistically significantly lower. There were no statistically significant differences in the apparent surface area of the roots which grew in pH 7, pH 4.5 without Al3+. The average water vapour adsorption energy of the root surface, under stress conditions decreased. In the roots grown in the presence of Al+3, there was a slight decrease in high energy adsorption centres and an increase in the amount of low-energy centres.

  2. High-emittance surfaces for high-temperature space radiator applications

    NASA Astrophysics Data System (ADS)

    Banks, Bruce A.; Miller, Sharon K.; Hotes, Deborah

    1991-01-01

    Anticipated space power systems which employ nuclear or solar dynamic power technologies may be required to reject waste heat at temperatures up to 950K. High temperature radiators will be required to have high thermal emittance surfaces which are durable to elevated temperatures as well as the operational space environment. Additional performance and durability threats such as extreme temperature variations and low earth orbital atomic oxygen impose challenging constraints upon the selection of suitable radiator surfaces. Traditional surface coatings which are acceptable for high emittance low temperature radiators may spall or degrade in an environment where large temperature changes high temperatures and atomic oxygen is present. Surface roughening and/or chemical modifications which produce high emittance surfaces that are an integral part of the radiator substrate may have much greater durability than coatings applied to radiator substrates. A variety of surface modification techniques have been evaluated for emittance enhancement of radiator surfaces. These techniques include: acid etching heat treating abrasion sputter texturing electro-chemical texturing arc texturing and atomic oxygen beam texturing. Candidate radiator surface materials investigated include: Nb-1 Zr Cu Ti Ti-6 Al-4 v 304 stainless steel Al6061-T6 Mo W and Ta. Results of durability evaluation of selected radiator surfaces in an atomic oxygen environment is also presented. 1.

  3. Enhancing Bremsstrahlung Radiation using Front Surface Target Structures

    NASA Astrophysics Data System (ADS)

    Jiang, Sheng; Krygier, Andrew; Schumacher, Douglass; Freeman, Richard; Akli, Kramer

    2014-10-01

    X-ray or γ-ray sources generated by laser solid interactions have many potential applications in different fields including X-ray radiography, pair production and photonuclear physics. Recent studies with 3D PIC modeling have shown that large scale front-surface target structures can significantly increase the energy and narrow the angular distribution of hot electrons compared to that for a regular flat target. These characteristics of electrons are crucial for further Bremsstrahlung production using a high-Z converter target. The corresponding Bremsstrahlung radiation covers a wide energy range and can be as high as 100 MeV. By performing the Monte-Carlo simulations we find that the peak γ-ray brightness is 6 . 0 * 1019 s-1 mm-2 mrad-2 at 10 MeV and 1 . 4 * 1019 s-1 mm-2 mrad-2 at 100 MeV (0.1% bandwidth), which is comparable to other tunable γ-ray sources. The brightness for high energy γ-rays (>50 MeV) is one or a few orders of magnitude higher using the structured target than the flat target. Simulation and preliminary experimental results will be presented. This work is supported by AFOSR Young Investigator Program and NNSA with computing time from the Ohio Supercomputer Center.

  4. The Effects of Landcover Pattern on Urban Surface Net Radiation Retrieved by Remote Sensing

    NASA Astrophysics Data System (ADS)

    Zhao, X.

    2015-12-01

    Taking Xiamen city as the study area, this research retrieved surface net radiation using meteorological data and Landsat 5 TM images of the four seasons in the year 2009. Meanwhile the 65 different landscape metrics of each analysis unit were acquired using landscape analysis method. Then the most effective landscape metrics affecting surface net radiation were determined by correlation analysis, partial correlation analysis, stepwise regression method, etc. At both class and landscape levels, this paper comprehensively analyzed the temporal and spatial variations of the surface net radiation as well as the effects of land cover pattern on it in Xiamen from a multi-seasonal perspective. The results showed that: Xiamen's surface net radiation is the maximum in summer, followed by spring, autumn. The surface net radiation in winter is the minimum. Net radiation flux is higher for water and forestland and is lower for built-up land and bare land, etc. The spatial composition of land cover pattern shows significant influence on surface net radiation. The proportion of bare land and the proportion of forest land are effective and important factors which affect the changes of surface net radiation all the year round. But the spatial allocation of land cover pattern has no significant influence on surface net radiation. Moreover, the proportion of forest land is more capable for explaining surface net radiation than the proportion of bare land. Its total annual explanatory ability is better than the latter. So the proportion of forest land is the most important and continuously effective factor which affects and explains the cross-seasonal differences of surface net radiation. This study is helpful in exploring the formation and evolution mechanism of urban heat island. It also gave theoretical hints and realistic guidance for urban planning and sustainable development.

  5. Satellite estimates of shortwave surface radiation and atmospheric meteorology for the BOREAS experiment region

    NASA Technical Reports Server (NTRS)

    Moats, C. D.; Whitlock, C. H.; Lecroy, S. R.; Dipasquale, R. C.

    1994-01-01

    This report provides background data for the Boreal Ecosystem Atmosphere Study (BOREAS) sites, including daily, seasonal, interannual, and spatial variability of shortwave (SW) radiation at the Earth's surface. This background data, from the Version 1.1 SW data set, was provided by the Surface Radiation Budget (SRB) Climatology Project established by the World Climate Research Program (WCRP).

  6. The "Chocolate Experiment"--A Demonstration of Radiation Absorption by Different Colored Surfaces

    ERIC Educational Resources Information Center

    Fung, Dennis

    2015-01-01

    In the typical "cookbook" experiment comparing the radiation absorption rates of different colored surfaces, students' hands are commonly used as a measurement instrument to demonstrate that dull black and silvery surfaces are good and poor absorbers of radiation, respectively. However, college students are often skeptical about using…

  7. Optical radiation from the interaction of energetic atoms, ions, electrons, and photons with surfaces

    NASA Technical Reports Server (NTRS)

    Tolk, N. H.; Albridge, R. G.; Haglund, R. F., Jr.; Mendenhall, M. H.

    1985-01-01

    Heavy particle, electron, and UV photon bombardment of solid surfaces has been recently observed to result in the emission of infrared, visible, and ultraviolet radiation. This effect occurs over a wide range of incident projectile energies. Line radiation arising from transitions between discrete atomic or molecular levels may be attributed to the decay of excited particles which have been sputtered or electronically/chemically desorbed from the surface. Broadband continuum radiation, which is also observed, is believed to arise either from fluorescence of the near surface bulk or from the radiative decay of desorbed excited clusters. Spacecraft, in the ambient near Earth environment, are subject to such bombardment. The dynamics of energetic particle and photon beam interactions with surfaces which lead to surface erosion and glow phenomena will be treated. In addition, projected experimental and theoretical studies of oxygen and nitrogen beam surface interactions on materials characteristic of spacecraft surfaces will be discussed.

  8. In vitro infrared thermographic assessment of root surface temperatures generated by high-temperature thermoplasticized injectable gutta-percha obturation technique.

    PubMed

    Lipski, Mariusz

    2006-05-01

    The aim of this in vitro study was to measure the temperature rises on the outer surface of roots produced by high-temperature thermoplasticized injectable gutta-percha technique. Thirty extracted human teeth with a single canal (15 maxillary central incisors and 15 mandibular central incisors) were used in this study. After root canal cleaning and shaping, the teeth were obturated with the injected gutta-percha heated to 160 degrees C (Obtura II). Temperature changes on the whole mesial outer surface of the roots was measured using an infrared thermal imaging camera. It showed that the use of gutta-percha heated to 160 degrees C to fill the maxillary central incisors and mandibular central incisors resulted in the rises of the root surface temperature by 8.5 degrees C and 22.1 degrees C, respectively. In conclusion, the injection of the gutta-percha heated to 160 degrees C into the root canal of maxillary central incisors produces temperature on the outer root surfaces below the theoretical critical level and, therefore, should not cause damage to supporting periradicular tissues. The injection of gutta-percha into the root canal space of the mandibular central incisors in vitro, resulted in an elevation of the root surface temperature by more than 10 degrees C.

  9. Development of a Space Radiation Monte-Carlo Computer Simulation Based on the FLUKE and Root Codes

    NASA Technical Reports Server (NTRS)

    Pinsky, L. S.; Wilson, T. L.; Ferrari, A.; Sala, Paola; Carminati, F.; Brun, R.

    2001-01-01

    The radiation environment in space is a complex problem to model. Trying to extrapolate the projections of that environment into all areas of the internal spacecraft geometry is even more daunting. With the support of our CERN colleagues, our research group in Houston is embarking on a project to develop a radiation transport tool that is tailored to the problem of taking the external radiation flux incident on any particular spacecraft and simulating the evolution of that flux through a geometrically accurate model of the spacecraft material. The output will be a prediction of the detailed nature of the resulting internal radiation environment within the spacecraft as well as its secondary albedo. Beyond doing the physics transport of the incident flux, the software tool we are developing will provide a self-contained stand-alone object-oriented analysis and visualization infrastructure. It will also include a graphical user interface and a set of input tools to facilitate the simulation of space missions in terms of nominal radiation models and mission trajectory profiles. The goal of this project is to produce a code that is considerably more accurate and user-friendly than existing Monte-Carlo-based tools for the evaluation of the space radiation environment. Furthermore, the code will be an essential complement to the currently existing analytic codes in the BRYNTRN/HZETRN family for the evaluation of radiation shielding. The code will be directly applicable to the simulation of environments in low earth orbit, on the lunar surface, on planetary surfaces (including the Earth) and in the interplanetary medium such as on a transit to Mars (and even in the interstellar medium). The software will include modules whose underlying physics base can continue to be enhanced and updated for physics content, as future data become available beyond the timeframe of the initial development now foreseen. This future maintenance will be available from the authors of FLUKA as

  10. Evaluation of root water uptake in the ISBA-A-gs land surface model using agricultural yield statistics over France

    NASA Astrophysics Data System (ADS)

    Canal, N.; Calvet, J.-C.; Decharme, B.; Carrer, D.; Lafont, S.; Pigeon, G.

    2014-05-01

    The interannual variability of cereal grain yield and permanent grassland dry matter yield is simulated over French sites by the Interactions between Soil, Biosphere and Atmosphere, CO2-reactive (ISBA-A-gs) generic Land Surface Model (LSM). The two soil profile schemes available in the model are used to simulate the above-ground biomass (Bag) of cereals and grasslands: a 2-layer force-restore (FR-2L) bulk reservoir model and a multi-layer diffusion (DIF) model. The DIF model is implemented with or without deep soil layers below the root-zone. The evaluation of the various root water uptake models is achieved by using the French agricultural statistics of Agreste over the 1994-2010 period at 45 cropland and 48 grassland sites, for a range of rooting depths. The number of sites where the simulated annual maximum Bag presents a significant correlation with the yield observations is used as a metric to benchmark the root water uptake models. Significant correlations (p value < 0.01) are found for up to 29% of the cereal sites and 77% of the grassland sites. It is found that modelling additional subroot zone base flow soil layers does not improve (and may even degrade) the representation of the interannual variability of the vegetation above-ground biomass. These results are particularly robust for grasslands as calibrated simulations are able to represent the extreme 2003 and 2007 years corresponding to unfavourable and favourable fodder production, respectively.

  11. The Effect of Non-Lambertian Surface Reflectance on Aerosol Radiative Forcing

    SciTech Connect

    Ricchiazzi, P.; O'Hirok, W.; Gautier, C.

    2005-03-18

    Surface reflectance is an important factor in determining the strength of aerosol radiative forcing. Previous studies of radiative forcing assumed that the reflected surface radiance is isotropic and does not depend on incident illumination angle. This Lambertian reflection model is not a very good descriptor of reflectance from real land and ocean surfaces. In this study we present computational results for the seasonal average of short and long wave aerosol radiative forcing at the top of the atmosphere and at the surface. The effect of the Lambertian assumption is found through comparison with calculations using a more detailed bi-direction reflectance distribution function (BRDF).

  12. Spatial Patterns of Radiative Forcing and Surface Temperature Response

    NASA Astrophysics Data System (ADS)

    Shindell, D. T.

    2014-12-01

    Examination of radiative forcing (RF), a key measure of changes in the energy balance of the Earth, facilitates understanding of the role of various drivers of climate change. For short-lived compounds, the RF can be highly inhomogeneous geographically. The relationship between the spatial patterns of RF and climate response is poorly characterized, however. Here we examine the relationship between RF and surface temperature response in the latest generation of climate models. We find that the geographic distribution of historical changes in aerosol and ozone RF strongly influences the response, leading to substantial regional differences with respect to the response to quasi-uniform well-mixed greenhouse gases (WMGHG). In particular, the response in the Northern Hemisphere (NH) extratropics and tropics follows the forcing in those regions fairly closely. There is a stronger global sensitivity to historical aerosol plus ozone RF than to WMGHG RF with equivalent global mean value, as noted previously [D T Shindell, 2014] and a stronger response in much of the NH extratropics, especially in and downwind of industrialized areas. The enhanced response is shown to be particularly large over land plus polar ocean areas, where transient response occurs more rapidly and strong snow and ice albedo feedbacks operate. This response is not attributable to greater forcing over those regions, but rather appears to reflect a broad sensitivity of NH extratropical land areas to NH extratropical forcing. The models show substantial diversity in the enhancement of land+polar ocean response to aerosols plus ozone relative to WMGHG, and for ocean response some models show reduced sensitivity to aerosols plus ozone (though the multi-model mean shows an enhancement), suggesting that different representations of land and ocean adjustment timescales and regional heat transport contribute greatly to the differences in response to inhomogeneous forcing. In addition, areas with greatest

  13. Radiation effects on the surfaces of the Galilean satellites

    NASA Astrophysics Data System (ADS)

    Johnson, R. E.; Carlson, R. W.; Cooper, J. F.; Paranicas, C.; Moore, M. H.; Wong, M. C.

    Early observations and results; Charged particle bombardment, variability; Dose vs.depth: radiation and regolith formation, trapping and escape; Radiation effects: irradiation of ice, irradiation of SO2 and sulfur - pure and in ice, irradiation of CO2 and carbon species in ice, irradiation of salts and acids, adsorption; Summary of satellite irradiation effects: Metis, Amalthea and Thebe, Io, Europa, Ganymede, Callisto.

  14. Retrieving high-resolution surface solar radiation with cloud parameters derived by combining MODIS and MTSAT data

    NASA Astrophysics Data System (ADS)

    Tang, Wenjun; Qin, Jun; Yang, Kun; Liu, Shaomin; Lu, Ning; Niu, Xiaolei

    2016-03-01

    Cloud parameters (cloud mask, effective particle radius, and liquid/ice water path) are the important inputs in estimating surface solar radiation (SSR). These parameters can be derived from MODIS with high accuracy, but their temporal resolution is too low to obtain high-temporal-resolution SSR retrievals. In order to obtain hourly cloud parameters, an artificial neural network (ANN) is applied in this study to directly construct a functional relationship between MODIS cloud products and Multifunctional Transport Satellite (MTSAT) geostationary satellite signals. In addition, an efficient parameterization model for SSR retrieval is introduced and, when driven with MODIS atmospheric and land products, its root mean square error (RMSE) is about 100 W m-2 for 44 Baseline Surface Radiation Network (BSRN) stations. Once the estimated cloud parameters and other information (such as aerosol, precipitable water, ozone) are input to the model, we can derive SSR at high spatiotemporal resolution. The retrieved SSR is first evaluated against hourly radiation data at three experimental stations in the Haihe River basin of China. The mean bias error (MBE) and RMSE in hourly SSR estimate are 12.0 W m-2 (or 3.5 %) and 98.5 W m-2 (or 28.9 %), respectively. The retrieved SSR is also evaluated against daily radiation data at 90 China Meteorological Administration (CMA) stations. The MBEs are 9.8 W m-2 (or 5.4 %); the RMSEs in daily and monthly mean SSR estimates are 34.2 W m-2 (or 19.1 %) and 22.1 W m-2 (or 12.3 %), respectively. The accuracy is comparable to or even higher than two other radiation products (GLASS and ISCCP-FD), and the present method is more computationally efficient and can produce hourly SSR data at a spatial resolution of 5 km.

  15. Retrieving high-resolution surface solar radiation with cloud parameters derived by combining MODIS and MTSAT data

    NASA Astrophysics Data System (ADS)

    Tang, W.; Qin, J.; Yang, K.; Liu, S.; Lu, N.; Niu, X.

    2015-12-01

    Cloud parameters (cloud mask, effective particle radius and liquid/ice water path) are the important inputs in determining surface solar radiation (SSR). These parameters can be derived from MODIS with high accuracy but their temporal resolution is too low to obtain high temporal resolution SSR retrievals. In order to obtain hourly cloud parameters, the Artificial Neural Network (ANN) is applied in this study to directly construct a functional relationship between MODIS cloud products and Multi-functional Transport Satellite (MTSAT) geostationary satellite signals. Meanwhile, an efficient parameterization model for SSR retrieval is introduced and, when driven with MODIS atmospheric and land products, its root mean square error (RMSE) is about 100 W m-2 for 44 Baseline Surface Radiation Network (BSRN) stations. Once the estimated cloud parameters and other information (such as aerosol, precipitable water, ozone and so on) are input to the model, we can derive SSR at high spatio-temporal resolution. The retrieved SSR is first evaluated against hourly radiation data at three experimental stations in the Haihe River Basin of China. The mean bias error (MBE) and RMSE in hourly SSR estimate are 12.0 W m-2 (or 3.5 %) and 98.5 W m-2 (or 28.9 %), respectively. The retrieved SSR is also evaluated against daily radiation data at 90 China Meteorological Administration (CMA) stations. The MBEs are 9.8 W m-2 (5.4 %); the RMSEs in daily and monthly-mean SSR estimates are 34.2 W m-2 (19.1 %) and 22.1 W m-2 (12.3 %), respectively. The accuracy is comparable or even higher than other two radiation products (GLASS and ISCCP-FD), and the present method is more computationally efficient and can produce hourly SSR data at a spatial resolution of 5 km.

  16. Extracting Metrics for Three-dimensional Root Systems: Volume and Surface Analysis from In-soil X-ray Computed Tomography Data.

    PubMed

    Suresh, Niraj; Stephens, Sean A; Adams, Lexor; Beck, Anthon N; McKinney, Adriana L; Varga, Tamas

    2016-01-01

    Plant roots play a critical role in plant-soil-microbe interactions that occur in the rhizosphere, as well as processes with important implications to climate change and crop management. Quantitative size information on roots in their native environment is invaluable for studying root growth and environmental processes involving plants. X-ray computed tomography (XCT) has been demonstrated to be an effective tool for in situ root scanning and analysis. We aimed to develop a costless and efficient tool that approximates the surface and volume of the root regardless of its shape from three-dimensional (3D) tomography data. The root structure of a Prairie dropseed (Sporobolus heterolepis) specimen was imaged using XCT. The root was reconstructed, and the primary root structure was extracted from the data using a combination of licensed and open-source software. An isosurface polygonal mesh was then created for ease of analysis. We have developed the standalone application imeshJ, generated in MATLAB(1), to calculate root volume and surface area from the mesh. The outputs of imeshJ are surface area (in mm(2)) and the volume (in mm(3)). The process, utilizing a unique combination of tools from imaging to quantitative root analysis, is described. A combination of XCT and open-source software proved to be a powerful combination to noninvasively image plant root samples, segment root data, and extract quantitative information from the 3D data. This methodology of processing 3D data should be applicable to other material/sample systems where there is connectivity between components of similar X-ray attenuation and difficulties arise with segmentation. PMID:27168248

  17. Extracting Metrics for Three-dimensional Root Systems: Volume and Surface Analysis from In-soil X-ray Computed Tomography Data.

    PubMed

    Suresh, Niraj; Stephens, Sean A; Adams, Lexor; Beck, Anthon N; McKinney, Adriana L; Varga, Tamas

    2016-01-01

    Plant roots play a critical role in plant-soil-microbe interactions that occur in the rhizosphere, as well as processes with important implications to climate change and crop management. Quantitative size information on roots in their native environment is invaluable for studying root growth and environmental processes involving plants. X-ray computed tomography (XCT) has been demonstrated to be an effective tool for in situ root scanning and analysis. We aimed to develop a costless and efficient tool that approximates the surface and volume of the root regardless of its shape from three-dimensional (3D) tomography data. The root structure of a Prairie dropseed (Sporobolus heterolepis) specimen was imaged using XCT. The root was reconstructed, and the primary root structure was extracted from the data using a combination of licensed and open-source software. An isosurface polygonal mesh was then created for ease of analysis. We have developed the standalone application imeshJ, generated in MATLAB(1), to calculate root volume and surface area from the mesh. The outputs of imeshJ are surface area (in mm(2)) and the volume (in mm(3)). The process, utilizing a unique combination of tools from imaging to quantitative root analysis, is described. A combination of XCT and open-source software proved to be a powerful combination to noninvasively image plant root samples, segment root data, and extract quantitative information from the 3D data. This methodology of processing 3D data should be applicable to other material/sample systems where there is connectivity between components of similar X-ray attenuation and difficulties arise with segmentation.

  18. Evaluation of surface energy and radiation balance systems on the Konza Prairie

    NASA Technical Reports Server (NTRS)

    Fritschen, Leo J.

    1987-01-01

    Four Surface Energy and Radiation Balance Systems (SERBS) were installed and operated for two weeks in Kansas during July of 1986. Surface energy and radiation balances were investigated on six sites on the Konza Prairie about 3 km south of Manhattan, Kansas. Measurements were made to allow the computation of these radiation components: total solar and diffuse radiation, reflected solar radiation, net radiation, and longwave radiation upward and downward. Measurements were made to allow the computation of the sensible and latent heat fluxes by the Bowen ratio method using differential psychrometers on automatic exchange mechanisms. The report includes a description of the experimental sites, data acquisition systems and sensors, data acquisitions system operating instructions, and software used for data acquisition and analysis. In addition, data listings and plots of the energy balance components for all days and systems are given.

  19. Radiative and Non-Radiative Lifetime Engineering of Quantum Dots in Multiple Solvents by Surface Atom Stoichiometry and Ligands

    PubMed Central

    Omogo, Benard; Aldana, Jose F.; Heyes, Colin D.

    2013-01-01

    CdTe quantum dots have unique characteristics that are promising for applications in photoluminescence, photovoltaics or optoelectronics. However, wide variations of the reported quantum yields exist and the influence of ligand-surface interactions that are expected to control the excited state relaxation processes remains unknown. It is important to thoroughly understand the fundamental principles underlying these relaxation processes to tailor the QDs properties to their application. Here, we systematically investigate the roles of the surface atoms, ligand functional groups and solvent on the radiative and non-radiative relaxation rates. Combining a systematic synthetic approach with X-ray photoelectron, quantitative FT-IR and time-resolved visible spectroscopies, we find that CdTe QDs can be engineered with average radiative lifetimes ranging from nanoseconds up to microseconds. The non-radiative lifetimes are anticorrelated to the radiative lifetimes, although they show much less variation. The density, nature and orientation of the ligand functional groups and the dielectric constant of the solvent play major roles in determining charge carrier trapping and excitonic relaxation pathways. These results are used to propose a coupled dependence between hole-trapping on Te atoms and strong ligand coupling, primarily via Cd atoms, that can be used to engineer both the radiative and non-radiative lifetimes. PMID:23543893

  20. Estimates of surface ultraviolet radiation over north America using Geostationary Operational Environmental Satellites observations

    NASA Astrophysics Data System (ADS)

    Gadhavi, H.; Pinker, R. T.; Laszlo, I.

    2008-11-01

    Information on ultraviolet (UV) radiative fluxes is needed for public safety, understanding biodiversity, and for chemical transport modeling. Space-based observations can provide homogeneous and systematic estimates of the UV flux over large regions. In the past, UV flux estimates have been made from polar orbiting satellites; such estimates lack information on diurnal variability that can result in significant errors in UV dose (diurnally integrated UV flux). An algorithm has been developed to estimate diurnally varying spectral UV flux at the surface based on information from geostationary satellites (cloud amount, surface albedo and aerosols) and from polar orbiting satellites (ozone). Algorithm evaluation is done by comparison with ground-based observations made between January 1998 and December 2000 over eighteen stations of the United States Department of Agriculture (USDA)'s UV monitoring network. A good agreement between ground-based observations and satellite estimates is found with a mean bias (satellite - ground) of +3.5% for all-sky (cloudy + clear) cases. A negative mean bias of the same magnitude is found for clear-sky cases. Root mean square (RMS) differences are 25% and 14% for all-sky and clear-sky cases, respectively. Using simulations, it is shown that when only one observation near noontime is used to estimate UV dose, errors in the range of -61% to 48% can result, depending on cloud conditions. The RMS difference is 9% and it increases to 13% when off-noon hour (±2 hrs) observations are used to estimate the UV flux over Queenstown, MD.

  1. Intrapulpal temperature changes during root surface irradiation with dual-wavelength laser (2780 and 940 nm): in vitro study

    NASA Astrophysics Data System (ADS)

    Franzen, Rene; Rashidisangsary, Borna; Ozturan, Seda; Vanweersch, Leon; Gutknecht, Norbert

    2015-01-01

    The present study evaluated the intrapulpal thermal changes that occurred during the treatment of the root surfaces with a laser system emitting Er,Cr:YSGG 2780- and 940-nm diode laser irradiation in an alternating sequence. Thirty single-rooted human teeth were collected. The teeth were divided into three groups (n=10 each) and irradiated with Er,Cr:YSGG alone or combined with a 940-nm diode laser. To investigate the intrapulpal temperature changes, specimens were embedded in a resin block with a set of thermocouples introduced at different positions within the root canals. The first group was irradiated with only Er,Cr:YSGG (25 mJ, 50 Hz, 50 μs pulse duration, water and air spray); the second group was irradiated with Er,Cr:YSGG (same setting) and a 940-nm diode (2 W, chopped mode with 20% duty cycle); the third group was irradiated with Er,Cr:YSGG (same setting) and a diode (2 W, chopped mode with 50% duty cycle). During all irradiations, thermal changes were recorded in real time with thermocouples. While group 3 showed thermal rises on average of 1.68±0.98°C in the pulp chamber, groups 1 and 2 showed average temperature rises of <0.5°C. The combined laser emission of 2780 and 940 nm is a promising way for root surface debridement without inducing intrapulpal thermal damage when using an appropriate water/air spray. All measured temperatures were considerably below the critical value of 5.6°C.

  2. Hypothetical Protein Avin_16040 as the S-Layer Protein of Azotobacter vinelandii and Its Involvement in Plant Root Surface Attachment

    PubMed Central

    Jong, Bor Chyan

    2015-01-01

    A proteomic analysis of a soil-dwelling, plant growth-promoting Azotobacter vinelandii strain showed the presence of a protein encoded by the hypothetical Avin_16040 gene when the bacterial cells were attached to the Oryza sativa root surface. An Avin_16040 deletion mutant demonstrated reduced cellular adherence to the root surface, surface hydrophobicity, and biofilm formation compared to those of the wild type. By atomic force microscopy (AFM) analysis of the cell surface topography, the deletion mutant displayed a cell surface architectural pattern that was different from that of the wild type. Escherichia coli transformed with the wild-type Avin_16040 gene displayed on its cell surface organized motifs which looked like the S-layer monomers of A. vinelandii. The recombinant E. coli also demonstrated enhanced adhesion to the root surface. PMID:26276116

  3. Surface photoconductivity of organosilicate glass dielectrics induced by vacuum-ultraviolet radiation

    NASA Astrophysics Data System (ADS)

    Zheng, H.; Nichols, M. T.; Pei, D.; Nishi, Y.; Shohet, J. L.

    2013-08-01

    The temporary increase in the electrical surface conductivity of low-k organosilicate glass (SiCOH) during exposure to vacuum-ultraviolet radiation (VUV) is investigated. To measure the photoconductivity, patterned "comb structures" are deposited on dielectric films and exposed to synchrotron radiation in the range of 8-25 eV, which is in the energy range of most plasma vacuum-ultraviolet radiation. The change in photo surface conductivity induced by VUV radiation may be beneficial in limiting charging damage of dielectrics by depleting the plasma-deposited charge.

  4. Surface photoconductivity of organosilicate glass dielectrics induced by vacuum-ultraviolet radiation

    SciTech Connect

    Zheng, H.; Nichols, M. T.; Pei, D.; Shohet, J. L.; Nishi, Y.

    2013-08-14

    The temporary increase in the electrical surface conductivity of low-k organosilicate glass (SiCOH) during exposure to vacuum-ultraviolet radiation (VUV) is investigated. To measure the photoconductivity, patterned “comb structures” are deposited on dielectric films and exposed to synchrotron radiation in the range of 8–25 eV, which is in the energy range of most plasma vacuum-ultraviolet radiation. The change in photo surface conductivity induced by VUV radiation may be beneficial in limiting charging damage of dielectrics by depleting the plasma-deposited charge.

  5. Relationship Between Landcover Pattern and Surface Net Radiation in AN Coastal City

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Liu, L.; Liu, X.; Zhao, Y.

    2016-06-01

    Taking Xiamen city as the study area this research first retrieved surface net radiation using meteorological data and Landsat 5 TM images of the four seasons in the year 2009. Meanwhile the 65 different landscape metrics of each analysis unit were acquired using landscape analysis method. Then the most effective landscape metrics affecting surface net radiation were determined by correlation analysis, partial correlation analysis, stepwise regression method, etc. At both class and landscape levels, this paper comprehensively analyzed the temporal and spatial variations of the surface net radiation as well as the effects of land cover pattern on it in Xiamen from a multi-seasonal perspective. The results showed that the spatial composition of land cover pattern shows significant influence on surface net radiation while the spatial allocation of land cover pattern does not. The proportions of bare land and forest land are effective and important factors which affect the changes of surface net radiation all the year round. Moreover, the proportion of forest land is more capable for explaining surface net radiation than the proportion of bare land. So the proportion of forest land is the most important and continuously effective factor which affects and explains the cross-seasonal differences of surface net radiation. This study is helpful in exploring the formation and evolution mechanism of urban heat island. It also gave theoretical hints and realistic guidance for urban planning and sustainable development.

  6. Effects of Er,Cr:YSGG Laser Treatment on Human Gingival Fibroblast Attachment, Viability and Morphology of Root Surface: An In Vitro Study.

    PubMed

    Amid, Reza; Azizi, Elahe; Ardakani, Mohammad Reza Talebi; Ashnagar, Sajjad; Moiahedi, Seyed Masoud

    2016-05-01

    Rehabilitation of periodontal support is the main goal of therapies for periodontitis. Hand instrumentation with curettes, piezoelectric ultrasonic scalers and lasers, such as Er,Cr:YSGG, are used for this purpose. This study was designed to evaluate human gingival fibroblast viability attachment to root surfac after modification with the mentioned therapeutic alternatives. Lasers showed significantly lower cell viability after 72 hours compared to hand instrumentation and ultrasound, probably due to more irregular root surfaces after treatment. PMID:27290823

  7. Ultraviolet Radiation-Elicited Enhancement of Isoflavonoid Accumulation, Biosynthetic Gene Expression, and Antioxidant Activity in Astragalus membranaceus Hairy Root Cultures.

    PubMed

    Jiao, Jiao; Gai, Qing-Yan; Wang, Wei; Luo, Meng; Gu, Cheng-Bo; Fu, Yu-Jie; Ma, Wei

    2015-09-23

    In this work, Astragalus membranaceus hairy root cultures (AMHRCs) were exposed to ultraviolet radiation (UV-A, UV-B, and UV-C) for promoting isoflavonoid accumulation. The optimum enhancement for isoflavonoid production was achieved in 34-day-old AMHRCs elicited by 86.4 kJ/m(2) of UV-B. The resulting isoflavonoid yield was 533.54 ± 13.61 μg/g dry weight (DW), which was 2.29-fold higher relative to control (232.93 ± 3.08 μg/g DW). UV-B up-regulated the transcriptional expressions of all investigated genes involved in isoflavonoid biosynthetic pathway. PAL and C4H were found to be two potential key genes that controlled isoflavonoid biosynthesis. Moreover, a significant increase was noted in antioxidant activity of extracts from UV-B-elicited AMHRCs (IC50 values = 0.85 and 1.08 mg/mL) in comparison with control (1.38 and 1.71 mg/mL). Overall, this study offered a feasible elicitation strategy to enhance isoflavonoid accumulation in AMHRCs and also provided a basis for metabolic engineering of isoflavonoid biosynthesis in the future.

  8. Ultraviolet Radiation-Elicited Enhancement of Isoflavonoid Accumulation, Biosynthetic Gene Expression, and Antioxidant Activity in Astragalus membranaceus Hairy Root Cultures.

    PubMed

    Jiao, Jiao; Gai, Qing-Yan; Wang, Wei; Luo, Meng; Gu, Cheng-Bo; Fu, Yu-Jie; Ma, Wei

    2015-09-23

    In this work, Astragalus membranaceus hairy root cultures (AMHRCs) were exposed to ultraviolet radiation (UV-A, UV-B, and UV-C) for promoting isoflavonoid accumulation. The optimum enhancement for isoflavonoid production was achieved in 34-day-old AMHRCs elicited by 86.4 kJ/m(2) of UV-B. The resulting isoflavonoid yield was 533.54 ± 13.61 μg/g dry weight (DW), which was 2.29-fold higher relative to control (232.93 ± 3.08 μg/g DW). UV-B up-regulated the transcriptional expressions of all investigated genes involved in isoflavonoid biosynthetic pathway. PAL and C4H were found to be two potential key genes that controlled isoflavonoid biosynthesis. Moreover, a significant increase was noted in antioxidant activity of extracts from UV-B-elicited AMHRCs (IC50 values = 0.85 and 1.08 mg/mL) in comparison with control (1.38 and 1.71 mg/mL). Overall, this study offered a feasible elicitation strategy to enhance isoflavonoid accumulation in AMHRCs and also provided a basis for metabolic engineering of isoflavonoid biosynthesis in the future. PMID:26370303

  9. WCRP surface radiation budget shortwave data product description, version 1.1

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Charlock, T. P.; Staylor, W. F.; Pinker, R. T.; Laszlo, I.; Dipasquale, R. C.; Ritchey, N. A.

    1993-01-01

    Shortwave radiative fluxes which reach the Earth's surface are key elements that influence both atmospheric and oceanic circulation. The World Climate Research Program has established the Surface Radiation Budget climatology project with the ultimate goal of determining the various components of the surface radiation budget from satellite data on a global scale. This report describes the first global product that is being produced and archived as part of that effort. The interested user can obtain the monthly global data sets free of charge using e-mail procedures.

  10. The WCRP/GEWEX Surface Radiation Budget Project Release 2: First Results at 1 Degree Resolution

    NASA Technical Reports Server (NTRS)

    Stackhouse, Paul W., Jr.; Cox, Stephen J.; Gupta, Shashi K.; DiPasquale, Roberta C.; Brown, Donald E.

    1999-01-01

    The earth s surface radiative budget in the solar wavelengths (i.e., shortwave) and thermal infrared wavelengths (i.e., longwave) is an important component of Earth s global energy balance and climate. As such, it was identified as a priority need by the World Climate Research Programme (WCRP) and thus a program was instituted at NASA to estimate the radiative flux quantities at the surface from space observations. The Surface Radiation Budget (SRB) Project was created and later included as a component of the Global Energy and Water Cycle Experiment (GEWEX) under the auspices of the WCRP.

  11. Clear-sky radiation trends derived from ground-based observations of surface solar radiation over Europe

    NASA Astrophysics Data System (ADS)

    Bartók, Blanka; Hakuba, Maria Z.; Sanchez-Lorenzo, Arturo; Wild, Martin

    2015-04-01

    Trends in clear-sky radiation reflect the changes in the radiatively active components of the atmosphere without considering the effect of clouds. In this way analyzing the long term changes in clear-sky radiation gives a better overview over the changes in aerosol content in the atmosphere, having significant direct radiative effect on surface solar radiation but no long term records of direct aerosol measurements exist. In this study, the linear trends of clear-sky radiation records over Europe are analyzed based on daily observations from 26 stations for the period of 1964-2013, which have been obtained from the Word Radiation Data Center (WRDC). The daily data has been checked for temporal homogeneity by applying the MASH method (Szentimrey, 2003). The separation of clear-sky situation is elaborated using three approaches. In the first approach the clear-sky situations are detected based on a clearness index, namely the ratio of the surface solar radiation to the extraterrestrial solar irradiation. In the second approach the observed values of surface solar radiation are compared to the climatology of clear-sky surface solar radiation calculated by the MAGIC radiation code (Muller et al. 2009). In the third approach clear-sky days are detected based on synoptic cloudiness observations. Overall, in all approaches the trends of clear-sky radiation may also depend on the thresholds of clear-sky days. Consequently, in order to eliminate this methodological error in all cases different thresholds are chosen and the sensitivity of clear-sky radiation trends with respect to the thresholds is quantified. In order to verify the reliability of the empirical thresholds, a verification of clear-sky detection is envisaged through a comparison with the values obtained by a high time resolution clear-sky detection and interpolation algorithm (Long and Ackermann, 2000) making use of the high quality data from the Baseline Surface Radiation Network (BSRN).The trends of clear

  12. SU-E-J-217: Accuracy Comparison Between Surface and Volumetric Registrations for Patient Setup of Head and Neck Radiation Therapy

    SciTech Connect

    Kim, Y; Li, R; Na, Y; Jenkins, C; Xing, L; Lee, R

    2014-06-01

    Purpose: Optical surface imaging has been applied to radiation therapy patient setup. This study aims to investigate the accuracy of the surface registration of the optical surface imaging compared with that of the conventional method of volumetric registration for patient setup in head and neck radiation therapy. Methods: Clinical datasets of planning CT and treatment Cone Beam CT (CBCT) were used to compare the surface and volumetric registrations in radiation therapy patient setup. The Iterative Closest Points based on point-plane closest method was implemented for surface registration. We employed 3D Slicer for rigid volumetric registration of planning CT and treatment CBCT. 6 parameters of registration results (3 rotations and 3 translations) were obtained by the two registration methods, and the results were compared. Digital simulation tests in ideal cases were also performed to validate each registration method. Results: Digital simulation tests showed that both of the registration methods were accurate and robust enough to compare the registration results. In experiments with the actual clinical data, the results showed considerable deviation between the surface and volumetric registrations. The average root mean squared translational error was 2.7 mm and the maximum translational error was 5.2 mm. Conclusion: The deviation between the surface and volumetric registrations was considerable. Special caution should be taken in using an optical surface imaging. To ensure the accuracy of optical surface imaging in radiation therapy patient setup, additional measures are required. This research was supported in part by the KIST institutional program (2E24551), the Industrial Strategic technology development program (10035495) funded by the Ministry of Trade, Industry and Energy (MOTIE, KOREA), and the Radiation Safety Research Programs (1305033) through the Nuclear Safety and Security Commission, and the NIH (R01EB016777)

  13. Shallow Subsurface Soil Moisture Dynamics in the Root-Zone and Bulk Soil of Sparsely Vegetated Land Surfaces as Impacted by Near-Surface Atmospheric State

    NASA Astrophysics Data System (ADS)

    Trautz, A.; Illangasekare, T. H.; Tilton, N.

    2015-12-01

    Soil moisture is a fundamental state variable that provides the water necessary for plant growth and evapotranspiration. Soil moisture has been extensively studied in the context of bare surface soils and root zones. Less attention has focused on the effects of sparse vegetation distributions, such as those typical of agricultural cropland and other natural surface environments, on soil moisture dynamics. The current study explores root zone, bulk soil, and near-surface atmosphere interactions in terms of soil moisture under different distributions of sparse vegetation using multi-scale laboratory experimentation and numerical simulation. This research is driven by the need to advance our fundamental understanding of soil moisture dynamics in the context of improving water conservation and next generation heat and mass transfer numerical models. Experimentation is performed in a two-dimensional 7.3 m long intermediate scale soil tank interfaced with a climate-controlled wind tunnel, both of which are outfitted with current sensor technologies for measuring atmospheric and soil variables. The soil tank is packed so that a sparsely vegetated soil is surrounded by bulk bare soil; the two regions are separated by porous membranes to isolate the root zone from the bulk soil. Results show that in the absence of vegetation, evaporation rates vary along the soil tank in response to longitudinal changes in humidity; soil dries fastest upstream where evaporation rates are highest. In the presence of vegetation, soil moisture in the bulk soil closest to a vegetated region decreases more rapidly than the bulk soil farther away. Evapotranspiration rates in this region are also higher than the bulk soil region. This study is the first step towards the development of more generalized models that account for non-uniformly distributed vegetation and land surfaces exhibiting micro-topology.

  14. Importance of root HTO uptake in controlling land-surface tritium dynamics after an-acute HT deposition: a numerical experiment.

    PubMed

    Ota, Masakazu; Nagai, Haruyasu; Koarashi, Jun

    2012-07-01

    To investigate the role of belowground root uptake of tritiated water (HTO) in controlling land-surface tritium (T) dynamics, a sophisticated numerical model predicting tritium behavior in an atmosphere-vegetation-soil system was developed, and numerical experiments were conducted using the model. The developed model covered physical tritiated hydrogen (HT) transport in a multilayered atmosphere and soil, as well as microbial oxidation of HT to HTO in the soil, and it was incorporated into a well-established HTO-transfer organically bound tritium (OBT)-formation model. The model performance was tested through the simulation of an existing HT-release experiment. Numerical experiments involving a hypothetical acute HT exposure to a grassland field with a range of rooting depths showed that the HTO release from the leaves to the atmosphere, driven by the root uptake of the deposited HTO, can exceed the HTO evaporation from the ground surface to the atmosphere when root water absorption preferentially occurs beneath the ground surface. Such enhanced soil-leaf-atmosphere HTO transport, caused by the enhanced root HTO uptake, increased HTO concentrations in both the surface atmosphere and in the cellular water of the leaf. Consequently, leaf OBT assimilation calculated for shallow rooting depths increased by nearly an order of magnitude compared to that for large rooting depths. PMID:22390945

  15. The initial attachment of cemental fibrils to the root dentin surface in acellular and cellular cementogenesis in rat molars.

    PubMed

    Yamamoto, T; Domon, T; Takahashi, S; Islam, M N; Suzuki, R

    2001-03-01

    To elucidate the initial attachment mechanism of cemental fibrils to the root dentin surface in acellular and cellular cementogenesis, developing rat molars were observed by light microscopy and scanning electron microscopy combined with NaOH maceration. The NaOH maceration was used to observe details of the positional association of cemental and dentinal fibrils during cementogenesis. An initial hematoxylin stained, cementum layer began to form on the root dentin surface with the first dentin mineralization in both acellular and cellular cementogenesis. The initial attachment of cemental fibrils to the dentin surface also began at this point. At the initial attachment the intermingling of cemental and dentinal fibrils occurred only in places. With advanced cementogenesis the initial cementum layer became the fibril-poor cemento-dentinal junction. This suggests that cemental fibrils attach on the initial cementum layer, and not directly on dentinal fibrils, so that the layer results in the fibril-poor cemento-dentinal junction. The present study suggests that an intervening adhesive is necessary for the cemento-dentinal attachment at any stage of cementogenesis in rat molars. PMID:11325058

  16. Energy and radiation balance components for three grass surfaces near Kursk, Russia

    NASA Technical Reports Server (NTRS)

    Fritschen, Leo J.

    1992-01-01

    The energy and radiation balance components were determined over three grass surfaces, located on the Streletskaya steppe during July 1991. The Bowen ratio energy balance method was used to determine the sensible and latent heat flux densities using six computer controlled systems. A total of 126 variables were sampled, including global, diffuse, and reflected solar radiation, long wave radiation (up and down), net radiation, photosynthetically active radiation above and below the vegetation, infrared surface temperatues, soil temperature and heat flow, air temperature and vapor pressure at two levels, wind speed and direction, and precipitation. The ranking of the sites from greatest to smallest for net radiation and latent heat flux density were preserve, mowed in 1990, and mowed in 1991. The ranking of the sites from greatest to smallest for sensible heat flux density were mowed in 1990, mowed in 1991, and preserve.

  17. Coherent and tunable terahertz radiation from graphene surface plasmon polaritons excited by an electron beam

    SciTech Connect

    Liu, Shenggang Hu, Min; Chen, Xiaoxing; Zhang, Ping; Gong, Sen; Zhao, Tao; Zhong, Renbin; Zhang, Chao

    2014-05-19

    Although surface plasmon polaritons (SPPs) resonance in graphene can be tuned in the terahertz regime, transforming such SPPs into coherent terahertz radiation has not been achieved. Here, we propose a graphene-based coherent terahertz radiation source with greatly enhanced intensity. The radiation works at room temperature, it is tunable and can cover the whole terahertz regime. The radiation intensity generated with this method is 400 times stronger than that from SPPs at a conventional dielectric or semiconducting surface and is comparable to that from the most advanced photonics source such as a quantum cascade laser. The physical mechanism for this strong radiation is presented. The phase diagrams defining the parameters range for the occurrence of radiation is also shown.

  18. In vitro assessment of a calcium-fluoroaluminosilicate glass-based desensitizer for the prevention of root surface demineralization.

    PubMed

    Miyajima, Hiroyuki; Ishimoto, Takuya; Ma, Sai; Chen, Jihua; Nakano, Takayoshi; Imazato, Satoshi

    2016-01-01

    The purpose of this study was to evaluate the ability of a calcium-fluoroaluminosilicate glass-based desensitizer (Nanoseal) to protect against root demineralization in vitro. Nanoseal was applied to human root dentin, which was immersed in acidic buffer for 72 h, or exposed to pH cycling by immersing in distilled water or mineralizing solution for 24 h intermediately during 48 h-acid attack. Demineralization was evaluated by μ-CT, and mineral loss (ML) and lesion depth (LD) were determined from mineral density profiles. ML and LD in all treatment groups were significantly smaller compared with control. The Nanoseal-treated group with pH cycling using mineralizing solution had the lowest ML and LD. Analysis using an EPMA demonstrated calcium and phosphorous were incorporated into the superficial layer of specimens in the Nanoseal-treated groups, suggesting Nanoseal modified the dentin surface, making it resistant to demineralization. Application of Nanoseal is an effective method for protecting root from demineralization. PMID:27251995

  19. Colonization on Root Surface by a Phenanthrene-Degrading Endophytic Bacterium and Its Application for Reducing Plant Phenanthrene Contamination

    PubMed Central

    Liu, Juan; Liu, Shuang; Sun, Kai; Sheng, Yuehui; Gu, Yujun; Gao, Yanzheng

    2014-01-01

    A phenanthrene-degrading endophytic bacterium, Pn2, was isolated from Alopecurus aequalis Sobol grown in soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Based on morphology, physiological characteristics and the 16S rRNA gene sequence, it was identified as Massilia sp. Strain Pn2 could degrade more than 95% of the phenanthrene (150 mg·L−1) in a minimal salts medium (MSM) within 48 hours at an initial pH of 7.0 and a temperature of 30°C. Pn2 could grow well on the MSM plates with a series of other PAHs, including naphthalene, acenaphthene, anthracene and pyrene, and degrade them to different degrees. Pn2 could also colonize the root surface of ryegrass (Lolium multiflorum Lam), invade its internal root tissues and translocate into the plant shoot. When treated with the endophyte Pn2 under hydroponic growth conditions with 2 mg·L−1 of phenanthrene in the Hoagland solution, the phenanthrene concentrations in ryegrass roots and shoots were reduced by 54% and 57%, respectively, compared with the endophyte-free treatment. Strain Pn2 could be a novel and useful bacterial resource for eliminating plant PAH contamination in polluted environments by degrading the PAHs inside plants. Furthermore, we provide new perspectives on the control of the plant uptake of PAHs via endophytic bacteria. PMID:25247301

  20. Clear-sky shortwave radiative closure for the Cabauw Baseline Surface Radiation Network site, Netherlands

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Knap, Wouter H.; Kuipers Munneke, Peter; Stammes, Piet

    2009-07-01

    In this paper a clear-sky shortwave closure analysis is presented for the Baseline Surface Radiation Network (BSRN) site of Cabauw, Netherlands (51.97°N, 4.93°E). The analysis is based on an exceptional period of fine weather during the first half of May 2008, resulting in a selection of 72 comparisons, on 6 days, between BSRN measurements and Doubling Adding KNMI (DAK) model simulations of direct, diffuse, and global irradiances. The data span a wide range of aerosol properties, water vapor columns, and solar zenith angles. The model input consisted of operational Aerosol Robotic Network (AERONET) aerosol products and radiosonde data. The wavelength dependence of the aerosol optical thickness, single scattering albedo, and asymmetry parameter was taken into account. On the basis of these data, excellent closure was obtained: the mean differences between model and measurements are 2 W/m2 (+0.2%) for the direct irradiance, 1 W/m2 (+0.8%) for the diffuse irradiance, and 2 W/m2 (+0.3%) for the global irradiance. The good results were obtained because of proper specification of the DAK model input and the high quality of the AERONET and BSRN measurements. The sensitivity of the achieved closure to uncertainties in the aerosol optical thickness, single scattering albedo, and asymmetry parameter was examined. Furthermore, several sensitivity experiments related to the wavelength dependence of the aerosol optical properties and the treatment of water vapor were performed. It appeared that a correct description of the wavelength dependence of the aerosol optical properties is important for achieving broadband closure. However, broadband closure can also be obtained by means of using spectrally averaged values of the single scattering albedo and the asymmetry parameter. Cancellation of errors in different parts of the solar spectrum also contributes to the achieved closure.

  1. Clear-sky shortwave radiative closure for the Cabauw Baseline Surface Radiation Network site, the Netherlands

    NASA Astrophysics Data System (ADS)

    Wang, P.; Knap, W. H.; Kuipers Munneke, P.; Stammes, P.

    2009-04-01

    During the last two decades, several attempts have been made to achieve agreement between clear-sky shortwave broadband irradiance models and surface measurements of direct and diffuse irradiance. In general, models and measurements agreed well for the direct component but closing the gap for diffuse irradiances remained problematic. The number of studies reporting a satisfactory degree of closure for both direct and diffuse irradiance is still limited, which motivated us to perform the study presented here. In this paper a clear-sky shortwave closure analysis is presented for the Baseline Surface Radiation Network (BSRN) site of Cabauw, the Netherlands (51.97 °N, 4.93 °E). The analysis is based on an exceptional period of fine weather in the first half of May 2008 during the Intensive Measurement Period At the Cabauw Tower (IMPACT), an activity of the European Integrated project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI). Although IMPACT produced a wealth of data, it was decided to conduct the closure analysis using routine measurements only, provided by BSRN and the Aerosol Robotic Network (AERONET), completed with radiosonde obervations. The rationale for this pragmatic approach is the possibility of applying the method presented here to other periods and (BSRN) sites, where routine measurements are readily available, without having to deal with the investments and restrictions of an intensive observation period. The analysis is based on a selection of 72 comparisons on 6 days between BSRN measurements and Doubling Adding KNMI (DAK) model simulations of direct, diffuse, and global irradiance. The data span a wide range of aerosol properties, water vapour columns, and solar zenith angles. The model input consisted of operational Aerosol Robotic Network (AERONET) aerosol products and radiosonde data. On the basis of these data excellent closure was obtained: the mean differences between model and measurements are 2 W/m2 (+0.2%) for direct

  2. Influence of tip wear of piezoelectric ultrasonic scalers on root surface roughness at different working parameters. A profilometric and atomic force microscopy study.

    PubMed

    Arabaci, T; Cicek, Y; Dilsiz, A; Erdogan, İ Y; Kose, O; Kizildağ, A

    2013-02-01

    Roughness on tooth surfaces is reported to facilitate the reestablishment of microbial dental plaque. Hence, the main goal of dental scaling is to remove bacterial plaque and obtain smoother tooth surfaces. This study was aimed to assess the influence of tip wear of ultrasonic scaler inserts on root surface roughness at different working parameters. Twenty piezoelectric ultrasonic scaler inserts (10 worn/10 new) were selected to examine the erosion ratio (ER) on the scaler tips and to assess the influence of tip wear on root surface roughness. Erosion on the tip surfaces was evaluated under atomic force microscopy (AFM). Root samples were prepared and instrumented by new (Group I) and worn (Group II) inserts at different working parameters. Roughness change (Rc) on root surfaces after instrumentation was examined under profilometer and compared between and within the groups. Statistically significant differences were found between the mean ERs of new and worn tips (P < 0.01). The results of this study showed that tip angulation and instrument power strongly influenced the Rc values on instrumented samples (P < 0.05). It was also revealed that tip wear influenced the Rc values on root surfaces especially at 45° tip angulation (P < 0.05). Therefore, tip wear should also be considered as much as the other parameters to minimize the surface roughness during ultrasonic treatment.

  3. Neutron radiative capture methods for surface elemental analysis

    USGS Publications Warehouse

    Trombka, J.I.; Senftle, F.; Schmadebeck, R.

    1970-01-01

    Both an accelerator and a 252Cf neutron source have been used to induce characteristic gamma radiation from extended soil samples. To demonstrate the method, measurements of the neutron-induced radiative capture and activation gamma rays have been made with both Ge(Li) and NaI(Tl) detectors, Because of the possible application to space flight geochemical analysis, it is believed that NaI(Tl) detectors must be used. Analytical procedures have been developed to obtain both qualitative and semiquantitative results from an interpretation of the measured NaI(Tl) pulse-height spectrum. Experiment results and the analytic procedure are presented. ?? 1970.

  4. Multiwavelength pyrometer for gray and non-gray surfaces in the presence of interfering radiation

    NASA Technical Reports Server (NTRS)

    Ng, Daniel L. P. (Inventor)

    1994-01-01

    A method and apparatus for detecting the temperature of gray and non-gray bodies in the presence of interfering radiation are presented. A gray body has a constant emissivity less than 1 and a non-gray body has an emissivity which varies with wavelength. The emissivity and reflectivity of the surface is determined over a range of wavelengths. Spectra are also measured of the extraneous interference radiation source and the surface of the object to be measured in the presence of the extraneous interference radiation source. An auxiliary radiation source is used to determine the reflectivity of the surface and also the emissivity. The measured spectrum of the surfaces in the presence of the extraneous interference radiation source is set equal to the emissivity of the surface multiplied by a Planck function containing a temperature term T plus the surface reflectivity multiplied by the spectrum of the extraneous interference radiation source. The equation is then solved for T to determine the temperature of the surface.

  5. Role of surface plasmon polaritons and other waves in the radiation of resonant optical dipole antennas.

    PubMed

    Jia, Hongwei; Liu, Haitao; Zhong, Ying

    2015-02-13

    The radiation of an electric dipole emitter can be drastically enhanced if the emitter is placed in the nano-gap of a metallic dipole antenna. By assuming that only surface plasmon polaritons (SPPs) are excited on the antenna, we build up an intuitive pure-SPP model that is able to comprehensively predict the electromagnetic features of the antenna radiation, such as the total or radiative emission rate and the far-field radiation pattern. With the model we can distinguish the respective contributions from SPPs and from other surface waves to the antenna radiation. It is found that for antennas with long arms that support higher-order resonances, SPPs provide a dominant contribution to the antenna radiation, while for other cases, the contribution of surface waves other than SPPs should be considered. The model reveals an intuitive picture that the enhancement of the antenna radiation is due to surface waves that are resonantly excited on the two antenna arms and that are further coupled into the nano-gap or scattered into free space. From the model we can derive a phase-matching condition that predicts the antenna resonance and the resultant enhanced radiation. The model is helpful for a physical understanding and intuitive design of antenna devices.

  6. Influence of Clouds On The Surface Radiative Balance For Two Mediterranean Sites

    NASA Astrophysics Data System (ADS)

    Bortoli, D.; Costa, M. J.; Nardino, M.

    Clouds strongly affect the Earth's climate influencing the surface radiative balance by reducing the incident solar radiation and increasing the downward longwave flux. Al- though the quantitative impact of clouds on the surface radiative balance is necessarily associated with great uncertainties due to the complexity and variation of the under- lying parameters, cloud radiative forcing is one of the main regulating factors of the Earth's climate. The present work aims at determining the effect of cloud coverage on the surface radiative balance, in order to contribute for a better understanding of local variations in the Mediterranean climate. Measurements of the cloud cover index (CCI) require the presence of an observer capable of quantifying cloud amounts in the sky in sight above the measurements' site. Since such measurements are not always available the cloud cover index is re- trieved using two different methodologies. On one hand the CCI is computed from the surface radiometer measurements throughout a parameterisation. On the other it is retrieved using a bi-spectral algorithm based on the METEOSAT satellite measure- ments from the visible and infrared spectral regions. Results of the CCI are compared with co-located observations to perform a general check against the available "ground truth". At the same time the CCI values obtained from both methodologies are inter- compared. Results of the CCI and their implications on the surface radiative balance are presented for the two Mediterranean sites selected, one located in Italy and the other in the south of Portugal. The cloud radiative forcing calculations show a cooling effect of the surface in presence of clouds for both sites. Moreover, a seasonal dependence is obtained, with a stronger cooling effect during summer. Acknowledgements: The work was supported by Instituto de Cooperação Científica e Tecnológica Internacional (ICCTI) - Portugal and Consiglio Nazionale delle Ricerche (CNR) - Italy

  7. Surface deformation effects induced by radiation pressure and electrostriction forces in dielectric solids

    NASA Astrophysics Data System (ADS)

    Astrath, N. G. C.; Lukasievicz, G. V. B.; Malacarne, L. C.; Bialkowski, S. E.

    2013-06-01

    The surface displacement produced by radiation pressure and electrostriction forces is investigated considering the commonly accepted theories proposed by Minkowski and Abraham for the energy-momentum tensor. The contributions are modeled considering each effect separately assuming non-absorbing and absorbing solids and the thermoelastic deformation equations are solved numerically. We show that the surface deformation profiles as calculated by the Minkowski or Abraham momenta give different surface curvature, which could in principle be detected by measuring the surface displacement. Finally, an all-optical pump-probe photothermal method to detect the radiation pressure and electrostriction forces in transparent dielectric solids is proposed.

  8. From dimming to brightening: decadal changes in solar radiation at Earth's surface.

    PubMed

    Wild, Martin; Gilgen, Hans; Roesch, Andreas; Ohmura, Atsumu; Long, Charles N; Dutton, Ellsworth G; Forgan, Bruce; Kallis, Ain; Russak, Viivi; Tsvetkov, Anatoly

    2005-05-01

    Variations in solar radiation incident at Earth's surface profoundly affect the human and terrestrial environment. A decline in solar radiation at land surfaces has become apparent in many observational records up to 1990, a phenomenon known as global dimming. Newly available surface observations from 1990 to the present, primarily from the Northern Hemisphere, show that the dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the late 1980s. This reversal is reconcilable with changes in cloudiness and atmospheric transmission and may substantially affect surface climate, the hydrological cycle, glaciers, and ecosystems. PMID:15879214

  9. From Dimming to Brightening: Decadal Changes in Solar Radiation at Earth's Surface

    SciTech Connect

    Wild, Martin F.; Gilgen, Hans; Roesch, Andreas; Ohmura, Atsumu; Long, Charles N.; Dutton, Ellsworth G.; Forgan, B. W.; Kallis, A.; Russak, V.; Tsvetkov, Anatoly

    2005-05-06

    Variations in solar radiation incident at Earth's surface profoundly affect the human and terrestrial environment. A decline in solar radiation at land surfaces has become apparent in many observational records up to 1990, a phenomenon known as global dimming. Newly available surface observations from 1990 to the present, primarily from the Northern Hemisphere, show that the dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the late 1980s. This reversal is reconcilable with changes in cloudiness and atmospheric transmission and may substantially affect surface climate, the hydrological cycle, glaciers, and ecosystems.

  10. A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study

    PubMed Central

    Prasanthi, Nalam NVD; Rambabu, Tanikonda; Sajjan, Girija S; Varma, K Madhu; Satish, R Kalyan; Padmaja, M

    2016-01-01

    Aim: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. Materials and Methods: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. Statistical Analysis: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. Results: Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. Conclusion: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems.

  11. A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study

    PubMed Central

    Prasanthi, Nalam NVD; Rambabu, Tanikonda; Sajjan, Girija S; Varma, K Madhu; Satish, R Kalyan; Padmaja, M

    2016-01-01

    Aim: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. Materials and Methods: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. Statistical Analysis: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. Results: Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. Conclusion: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems. PMID:27656062

  12. Solar Irradiance Changes And Photobiological Effects At Earth's Surface Following Astrophysical Ionizing Radiation Events

    NASA Astrophysics Data System (ADS)

    Thomas, Brian; Neale, Patrick

    2016-01-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth for decades. Although there is some direct biological damage on the surface from redistributed radiation several studies have indicated that the greatest long term threat is from ozone depletion and subsequent heightened solar ultraviolet (UV) radiation. It is known that organisms exposed to this irradiation experience harmful effects such as sunburn and even direct damage to DNA, proteins, or other cellular structures. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In the present work, we employed a radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light). Using biological weighting functions we have considered a wide range of effects, including: erythema and skin cancer in humans; inhibition of photosynthesis in the diatom Phaeodactylum sp. and dinoflagellate Prorocentrum micans inhibition of carbon fixation in Antarctic phytoplankton; inhibition of growth of oat (Avena sativa L. cv. Otana) seedlings; and cataracts. We found that past work overestimated UVB irradiance, but that relative estimates for increase in exposure to DNA damaging radiation are still similar to our improved calculations. We also found that the intensity of biologically damaging radiation varies widely with organism and specific impact considered; these results have implications for biosphere-level damage following astrophysical ionizing radiation events. When considering changes in surface-level visible light irradiance, we found that, contrary to previous assumptions, a decrease in irradiance is only present for a short time in

  13. Evaluating solar radiation on a tilted surfaces - a study case in Timis (Romania)

    NASA Astrophysics Data System (ADS)

    Vasar, C.; Prostean, O.; Prostean, G.

    2016-02-01

    In the last years the usage of solar energy has grown considerably in Romania, as well as in Europe, stimulated by various factors as government programs, green pricing policies, decreasing of photovoltaic components cost etc. Also, the rising demand of using Solar Energy Conversion Systems (SECS) is driven by the desire of individuals or companies to obtain energy from a clean renewable source. In many applications, remote consumers far from other energetic grids can use solar systems more cost-effectively than extending the grid to reach the location. Usually the solar energy is measured or forecast on horizontal surface, but in SECS there is needed the total solar radiation incident on the collector surface, that is oriented in a position that maximize the harvested energy. There are many models that convert the solar radiation from horizontal surface to a tilted surface, but they use empirical coefficients and the accuracy is influenced by different facts as geographical location or sky conditions. Such models were used considering measured values for solar radiation on horizontal plane, in the western part of Romania. Hourly values measured for global solar irradiation on the horizontal plane, diffuse solar irradiation on the horizontal plane and reflected solar irradiation by ground are used to compute the total solar radiation incident on different tilted surfaces. The calculated incident radiation is then compared with the real radiation measured on tilted surface in order to evaluate the performance of the considered conversion models.

  14. An Analytical Solution of Radiative Transfer in the Coupled Atmosphere-Ocean System with Rough Surface

    NASA Technical Reports Server (NTRS)

    Jin, Zhonghai; Charlock, Thomas P.; Rutledge, Ken; Knut Stamnes; Wang, Yingjian

    2006-01-01

    Using the efficient discrete-ordinate method, we present an analytical solution for radiative transfer in the coupled atmosphere-ocean system with rough air-water interface. The theoretical formulations of the radiative transfer equation and solution are described. The effects of surface roughness on radiation field in the atmosphere and ocean are studied and compared with measurements. The results show that ocean surface roughness has significant effects on the upwelling radiation in the atmosphere and the downwelling radiation in the ocean. As wind speed increases, the angular domain of sunglint broadens, the surface albedo decreases, and the transmission to ocean increases. The downward radiance field in the upper ocean is highly anisotropic, but this anisotropy decreases rapidly as surface wind increases and as depth in ocean increases. The effects of surface roughness on radiation also depend greatly on both wavelength and angle of incidence (i.e., solar elevation); these effects are significantly smaller throughout the spectrum at high sun. The model-observation discrepancies may indicate that the Cox-Munk surface roughness model is not sufficient for high wind conditions.

  15. EFFECTS OF LASER RADIATION ON MATTER: Growth of periodic structures on the surface of germanium subjected to pulsed laser radiation

    NASA Astrophysics Data System (ADS)

    Barsukov, D. O.; Gusakov, G. M.; Frolov, A. I.

    1991-12-01

    An experimental investigation was made of the dynamics of growth of periodic surface structures due to the interaction with pulsed laser radiation. Samples of Ge were subjected to laser pulses (λ = 1.06 μm, τ = 70 ns) with energy densities in the range 0.5-5.5 J/cm2. An investigation was made of the dynamics of the first-order diffraction of probe (λ = 0.53 μm) laser pulses with a time resolution 4 ns when p- and s-polarized laser radiation was incident at angles close to normal. A strong nonlinearity of the growth of such periodic surface structures was observed. The energy density from which such growth began depended on the quality of the polished Ge surface. The parameters of the dynamics of the growth of these structures were estimated.

  16. Spatial regression between soil surface elevation, water storage in root zone and biomass productivity of alfalfa within an irrigated field

    NASA Astrophysics Data System (ADS)

    Zeyliger, Anatoly; Ermolaeva, Olga

    2014-05-01

    Efficiency of water use for the irrigation purposes is connected to the variety of circumstances, factors and processes appearing along the transportation path of water from its sources to the root zone of the plant. Water efficiency of agricultural irrigation is connected with variety of circumstances, the impacts and the processes occurring during the transportation of water from water sources to plant root zone. Agrohydrological processes occur directly at the irrigated field, these processes linked to the infiltration of the applied water subsequent redistribution of the infiltrated water within the root zone. One of them are agrohydrological processes occurring directly on an irrigated field, connected with infiltration of water applied for irrigation to the soil, and the subsequent redistribution of infiltrated water in the root zone. These processes have the strongly pronounced spatial character depending on the one hand from a spatial variation of some hydrological characteristics of soils, and from other hand with distribution of volume of irrigation water on a surface of the area of an irrigated field closely linked with irrigation technology used. The combination of water application parameters with agrohydrological characteristics of soils and agricultural vegetation in each point at the surface of an irrigated field leads to formation of a vector field of intensity of irrigation water. In an ideal situation, such velocity field on a soil surface should represent uniform set of vertically directed collinear vectors. Thus values of these vectors should be equal to infiltration intensities of water inflows on a soil surface. In soil profile the field of formed intensities of a water flow should lead to formation in it of a water storage accessible to root system of irrigated crops. In practice this ideal scheme undergoes a lot of changes. These changes have the different nature, the reasons of occurrence and degree of influence on the processes connected

  17. Diversity patterns of Rhizobiaceae communities inhabiting soils, root surfaces and nodules reveal a strong selection of rhizobial partners by legumes.

    PubMed

    Miranda-Sánchez, Fabiola; Rivera, Javier; Vinuesa, Pablo

    2016-09-01

    Current knowledge about rhizobial diversity patterns in non-nodule habitats is scarce, limiting our understanding of basic aspects of rhizobial ecology like competitiveness for nodule occupancy and host effects on community structure. We used a combination of cultivation-dependent and independent approaches to analyse alpha and beta diversity patterns of Rhizobiaceae communities from a conserved seasonally dry tropical forest site in central Mexico and two nearby agricultural fields. Lineage-specific recA amplicon libraries were generated from soil DNA and their sequences compared with those from root surface and nodule isolates recovered in trapping experiments from two native Acacia species and two Phaseolus vulgaris cultivars. Rarefaction analyses revealed that Rhizobiaceae diversity in soils is larger than on root surfaces, and smallest in nodules. A 'rare biosphere'-like distribution of species was found in the three habitats. Multivariate statistical analyses demonstrated that the plant genus exerted a stronger influence than the land-usage regime on the diversity of rhizobia associated with hosts. Rhizobium etli was the dominant Rhizobiaceae found in the soil libraries. It dominated nodulation of Acacia spp. and predominately harboured symbiovar mimosae-like nodC genes. A novel Rhizobium lineage (Rsp1) dominated bean nodulation. Specialist and generalist genotypes for host nodulation were detected in both species. PMID:26395550

  18. Assimilation of Smos Observations to Generate a Prototype SMAP Level 4 Surface and Root-Zone Soil Moisture Product

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; De Lannoy, Gabrielle J. M.; Crow, Wade T.; Koster, Randal D.; Kimball, John

    2012-01-01

    The Soil Moisture Active and Passive (SMAP; [1]) mission is being implemented by NASA for launch in October 2014. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, the high-resolution soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. The Soil Moisture and Ocean Salinity (SMOS; [2]) mission was launched by ESA in November 2009 and has since been observing L-band (1.4 GHz) upwelling passive microwaves. In this paper we describe our use of SMOS brightness temperature observations to generate a prototype of the planned SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) product [5].

  19. EFFECTS OF LASER RADIATION ON MATTER: Role of the external photoelectric effect in surface microprocessing

    NASA Astrophysics Data System (ADS)

    Ageev, Vladimir P.; Konov, Vitalii I.; Krechetov, A. I.

    1990-08-01

    An analysis is made of the photoemission of electrons in gases when the surface of a solid is subjected to high-intensity ultraviolet laser radiation which does not cause surface heating. Various situations are considered in which generation of high local electric fields and of a dense cloud of charged particles near the surface may alter and even determine the mechanism of laser-stimulated processes on surfaces of solids.

  20. Near-surface silica does not increase radiative heat dissipation from plant leaves

    NASA Astrophysics Data System (ADS)

    Olof Björn, Lars; Li, Shaoshan

    2011-07-01

    It has been suggested that plants are able to increase radiative heat dissipation from their leaves by depositing near-surface silica, in this way increasing emissivity of infrared radiation and lowering leaf temperature. In order to test this theory, we have compared emissivity and radiative dissipation over the mid-infrared range 2.5-22.3 μm of leaves of plants that accumulate silica and plants that do not. Our data do not support the theory that accumulation of silica increases radiative heat dissipation by plant leaves.

  1. Smart Surfaces: New Coatings & Paints with Radiation Detection Functionality

    SciTech Connect

    Farmer, J; Choi, J

    2007-03-12

    Paints are being developed and tested that might ultimately be able to detect radiological agents in the environment by incorporating special pigments into an organic polymeric binder that can be applied as a paint or coatings. These paints detect radioactive sources and contaminants with inorganic or organic scintillation or thermo-luminescent pigments, which are selected based upon the radiation ({alpha}, {beta}, {gamma} or n) to be detected, and are shown in Figure 1.

  2. Clinical evaluation of demineralization and remineralization of intact root surface lesions in the clinic by a quantitative light-induced fluorescence system.

    PubMed

    Durmusoglu, Oykü; Tağtekin, Dilek Arslantunali; Yanikoğlu, Funda

    2012-03-01

    Detection of demineralization of root surface caries is an important issue since preventive approaches prolong tooth life. Quantitative light-induced fluorescence (QLF) has been shown to be useful for the laboratory assessment of demineralization of root surfaces. The aim of this study was to determine the demineralization and remineralization of root surface intact and cavitated caries lesions using a QLF system as a nondestructive in vivo method. Noncavitated and demineralized root surface lesions were detected and scored using the QLF system. Oral hygiene education was given and periodontal cleaning was completed before the remineralization treatment. After obtaining baseline QLF data, the patients were informed about the remineralization treatment. Fluoride varnish was applied to the carious lesions at the baseline visit, and the patients were then reviewed after 1, 2, 3 and 4 weeks, with QLF assessment and fluoride varnish application repeated at each review. Repeated-measures ANOVA (α = 0.05) showed significant differences between ΔQ values at each visit (p < 0.001); ΔQ showed marked decreases at all the cut-off values (15, 20, 25, 30). The changes in ΔQ were not affected by the cut-off value. The ΔQ values of QLF showed differences at all visits. The QLF system was able to detect early root surface caries lesions in vivo. Bifluoride 12 varnish improved mineral levels as shown by the QLF system. The treatment response to chemicals of intact noncavitated root surface carious lesions could be followed nondestructively in the clinic using QLF to quantify remineralization at recall visits. Teeth with root surface caries can be kept by controlling their remineralization.

  3. Effect of enhanced UV-B radiation on methane emission in a paddy field and rice root exudation of low-molecular-weight organic acids.

    PubMed

    He, Yongmei; Zhan, Fangdong; Li, Yuan; Xu, Weiwei; Zu, Yanqun; Yue, Ming

    2016-06-01

    A local rice variety, "Baijiaolaojing", was grown in a paddy field in the Yuanyang rice terraces under ambient and supplemental levels of ultraviolet-B (UV-B, 280-315 nm) radiation. The effects of enhanced UV-B radiation (5 and 10 kJ m(-2) d(-1)) on methane emissions in the paddy field were evaluated using a closed-chamber gas chromatography-based system, and the contents of low-molecular-weight organic acids (LMWOAs) in root exudates were determined by high-performance liquid chromatography (HPLC). Peaks in methane emissions in the paddy field were detected at 60, 80 and 100 days after rice transplantation. The highest level of cumulative methane emissions occurred at the tillering stage, followed by the jointing-booting and maturity stages. The lowest level was found at the flowering stage. The enhanced UV-B radiation did not change the seasonal variation in methane emissions in the paddy field; however, it induced a significant increase in the flux of methane emissions at the jointing-booting and maturity stages, as well as a significant increase in the cumulative flux of methane emissions throughout the growth period. In addition, the enhanced UV-B radiation caused an increase in the contents of oxalic acid and succinic acid and a decrease in the contents of tartaric acid and malic acid in rice root exudates. Furthermore, a significant positive correlation (r = 0.725, p < 0.01) was found between the content of oxalic acid and the methane emissions in the paddy field. The results indicated that enhanced UV-B radiation promoted methane emissions in the paddy field, which was closely associated with its impact on the exudation of LMWOAs by rice roots. PMID:27194164

  4. Radiative decay engineering 3. Surface plasmon-coupled directional emission

    PubMed Central

    Lakowicz, Joseph R.

    2009-01-01

    A new method of fluorescence detection that promises to increase sensitivity by 20- to 1000-fold is described. This method will also decrease the contribution of sample autofluorescence to the detected signal. The method depends on the coupling of excited fluorophores with the surface plasmon resonance present in thin metal films, typically silver and gold. The phenomenon of surface plasmon-coupled emission (SPCE) occurs for fluorophores 20–250 nm from the metal surface, allowing detection of fluorophores over substantial distances beyond the metal–sample interface. SPCE depends on interactions of the excited fluorophore with the metal surface. This interaction is independent of the mode of excitation; that is, it does not require evanescent wave or surface-plasmon excitation. In a sense, SPCE is the inverse process of the surface plasmon resonance absorption of thin metal films. Importantly, SPCE occurs over a narrow angular distribution, converting normally isotropic emission into easily collected directional emission. Up to 50% of the emission from unoriented samples can be collected, much larger than typical fluorescence collection efficiencies near 1% or less. SPCE is due only to fluorophores near the metal surface and may be regarded as emission from the induced surface plasmons. Autofluorescence from more distal parts of the sample is decreased due to decreased coupling. SPCE is highly polarized and autofluorescence can be further decreased by collecting only the polarized component or only the light propagating with the appropriate angle. Examples showing how simple optical configurations can be used in diagnostics, sensing, or biotechnology applications are presented. Surface plasmon-coupled emission is likely to find widespread applications throughout the biosciences. PMID:14690679

  5. Convection and surface tension profiles for aqueous droplet under microwave radiation

    NASA Astrophysics Data System (ADS)

    Kanazawa, Yushin; Asada, Masahiro; Asakuma, Yusuke; Honda, Itsuro; Phan, Chi; Parmar, Harisinh; Pareek, Vishnu; Evans, Geoffrey

    2014-08-01

    Application of microwave irradiation for chemical processes, such as emulsification and polymerization, has been reported [1,2]. Surfactant free emulsion can be produced with the help of microwave irradiation. Surface tension is an important property for the industrial process such as foaming/defoaming, wetting/dewetting and flotation. Similarly, the interfacial tension plays crucial role in separation and mixing process of two immiscible liquids, which are important unit operations of the fundamental chemical engineering. In practice, surface and interfacial tensions are often altered by introducing surfactants. In our previous research [3,4], specific property for surface tension of water droplet with salt under microwave radiation was found. For example, lower surface tension after the radiation was measured. The formation of nano-bubble will explain this behavior. Normally, the surface tension of aqueous solution increases with the salt concentration because cation and anion collect water molecule more strongly as a solvation. However, the exact mechanism of surface tension reduction by microwave radiation is not clear. We tried not only measurement of surface tension but also convection in the droplet during microwave radiation. This study investigates the influence of microwave on surface tension of aqueous solution. Moreover, relation between the concentration, temperature and droplet shape, which are related with surface tension.

  6. Application of adsorption methods to determine the effect of pH and Cu-stress on the changes in the surface properties of the roots

    NASA Astrophysics Data System (ADS)

    Szatanik-Kloc, Alicja

    2014-10-01

    Rye plants were grown in a nutrient solution prepared according to Hoagland for 2 weeks at pH 7, next for 14 days at pH 4.5 (without Cu+2) and in the presence of 20, 50, or 100 mg dm-3 copper ions. The control plants were grown continuously at pH 7. The physicochemical surface properties of the roots were examined using two adsorbates - polar (water vapour) and non-polar (nitrogen). The surface properties of the roots grown at pH 4.5 without Cu+2 were apparently the same as those of controls. The roots of rye which grew in the presence of Cu+2 were characterized by lower (relative to controls) specific surface area values. Statistically significant differences in the size of the apparent surface area (determined by water vapour) were reported for roots incubated with copper ions at a concentration of 20 and 50 mg dm-3. The average water vapour adsorption energy of the root surface decreased under the stress conditions. There were no statistically significant differences for the free surface area and characteristic energy of nitrogen adsorption.

  7. Interaction of soft x-ray laser pulse radiation with aluminum surface: Nano-meter size surface modification

    SciTech Connect

    Ishino, Masahiko; Faenov, Anatoly; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Tamotsu, Satoshi; Pikuz, Tatiana; Inogamov, Nail; Zhakhovsky, Vasily; Skobelev, Igor; Fortov, Vladimir; Khohlov, Viktor; Shepelev, Vadim; Ohba, Toshiyuki; Kaihori, Takeshi; Ochi, Yoshihiro; Imazono, Takashi; Kawachi, Tetsuya

    2012-07-11

    Interaction of soft x-ray laser radiation with material and caused modification of the exposed surface has both physical and practical interests. We irradiated the focusing soft x-ray laser (SXRL) pulses having a wavelength of 13.9 nm and the duration of 7 ps to aluminum (Al) surface. After the SXRL irradiation process, the irradiated Al surface was observed with a scanning electron microscope. The surface modifications caused by SXRL single pulse exposure were clearly seen. In addition, it was found that the conical structures having around 100 nm in diameters were formed in the shallow features. The nano-meter size modified structures at Al surface induced by SXRL pulse is interesting as the newly surface structure. Hence, the SXRL beam would be a candidate for a tool of micromachining. We also provide a thermomechanical modeling of SXRL interaction with Al briefly to explain the surface modification.

  8. Evaluation and Applications of the satellite-based CM SAF Solar Surface Radiation Climate Data Set

    NASA Astrophysics Data System (ADS)

    Trentmann, J.; Herzog, S.; Kothe, S.; Mueller, R. W.; Pfeifroth, U.; Ahrens, B.; Sanchez-Lorenzo, A.

    2015-12-01

    The incoming surface solar radiation has been defined as an essential climate variable by GCOS. It is mandatory to monitor this part of the earth's energy balance, and thus gain insights on the state and variability of the climate system. In addition, data sets of surface solar radiation have received increased attention over the recent years as an important source of information for solar energy applications. The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) is deriving surface solar radiation from geostationary and polar-orbiting satellite instruments. While CM SAF is focusing on high-quality long-term climate data records, operational data is also provided with a short time latency within about 2 weeks. Here we present the SARAH data set (Solar Surface Radiation Dataset - Heliosat) based on Meteosat satellite observations. SARAH provides hourly, daily- and monthly-averaged data of the effective cloud albedo (CAL), the direct normalized solar radiation (DNI) and the solar irradiance (SIS) from 1983 to 2013 for the full view of the Meteosat satellite (i.e, Europe, Africa, parts of South America, and the Atlantic ocean). The data sets are generated with a high spatial resolution of 0.05 deg allowing for detailed regional studies, and are available in netcdf-format at no cost without restrictions at www.cmsaf.eu. The mean absolute bias (i.e., the accuracy) of the SARAH data set as compared to surface reference observations has been determined to be 5.5 W/m2 for SIS and 8.2 W/m2 for DNI, i.e., within the accuracy of the ground-based measurements. The interannual and decadal variability of the SARAH SIS data are comparable to surface observations in Europe, although with a tendency to underestimate the mean increase in surface solar radiation (1.65 W/m2/dec compared to 3.3 W/m2/dec). Substantial temporal and spatial variability in the overall increase in surface solar radiation is found in the SARAH data set. Temporal changes in the frequency

  9. Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover.

    PubMed

    Hassler, Donald M; Zeitlin, Cary; Wimmer-Schweingruber, Robert F; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L; Brinza, David E; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P

    2014-01-24

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

  10. Mars' Surface Radiation Environment Measured with the Mars Science Laboratory's Curiosity Rover

    NASA Astrophysics Data System (ADS)

    Hassler, Donald M.; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L.; Brinza, David E.; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A.; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A.; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P.; MSL Science Team; Kemppinen, Osku; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; Berger, Thomas; Matthia, Daniel; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Lasue, Jérémie; Lee, Qiu-Mei; Maurice, Sylvestre; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Dromart, Gilles; Robert, François; Sautter, Violaine; Le Mouélic, Stéphane; Mangold, Nicolas; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Wiens, Roger C.; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Williams, Rebecca M. E.; Yingst, Aileen; Lewis, Kevin; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Hamilton, Victoria; Peterson, Joseph; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; García, César Martín; Mueller-Mellin, Reinhold; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

    2014-01-01

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

  11. Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover.

    PubMed

    Hassler, Donald M; Zeitlin, Cary; Wimmer-Schweingruber, Robert F; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L; Brinza, David E; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P

    2014-01-24

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment. PMID:24324275

  12. Surface solar ultraviolet radiation for paleoatmospheric levels of oxygen and ozone

    NASA Technical Reports Server (NTRS)

    Levine, J. S.

    1980-01-01

    Many investigators have concluded that the level of solar ultraviolet radiation (200-300 nm) reaching the surface was a key parameter in the origin and evolution of life on earth. The level of solar ultraviolet radiation between 200 and 300 nm is controlled primarily by molecular absorption by ozone, whose presence is strongly coupled to the level of molecular oxygen. In this paper, a series of calculations is presented of the solar ultraviolet radiation reaching the surface for oxygen levels ranging from 0.0001 the present atmospheric level to the present level. The solar spectrum between 200 and 300 nm has been divided into 34 spectral intervals. For each spectral interval, the solar ultraviolet radiation reaching the earth's surface has been calculated by considering the attenuation of the incoming beam due to ozone and oxygen absorption. A one-dimensional photochemical model of the atmosphere was used for these calculations.

  13. Solar irradiance changes and photobiological effects at earth's surface following astrophysical ionizing radiation events.

    PubMed

    Thomas, Brian C; Neale, Patrick J; Snyder, Brock R

    2015-03-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in surface-level solar ultraviolet radiation. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In this work, we employed the Tropospheric Ultraviolet and Visible (TUV) radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light) for clear-sky conditions and fixed aerosol parameter values. We also considered a wide range of biological effects on organisms ranging from humans to phytoplankton. We found that past work overestimated UVB irradiance but that relative estimates for increase in exposure to DNA-damaging radiation are still similar to our improved calculations. We also found that the intensity of biologically damaging radiation varies widely with organism and specific impact considered; these results have implications for biosphere-level damage following astrophysical ionizing radiation events. When considering changes in surface-level visible light irradiance, we found that, contrary to previous assumptions, a decrease in irradiance is only present for a short time in very limited geographical areas; instead we found a net increase for most of the modeled time-space region. This result has implications for proposed climate changes associated with ionizing radiation events.

  14. Solar irradiance changes and photobiological effects at earth's surface following astrophysical ionizing radiation events.

    PubMed

    Thomas, Brian C; Neale, Patrick J; Snyder, Brock R

    2015-03-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in surface-level solar ultraviolet radiation. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In this work, we employed the Tropospheric Ultraviolet and Visible (TUV) radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light) for clear-sky conditions and fixed aerosol parameter values. We also considered a wide range of biological effects on organisms ranging from humans to phytoplankton. We found that past work overestimated UVB irradiance but that relative estimates for increase in exposure to DNA-damaging radiation are still similar to our improved calculations. We also found that the intensity of biologically damaging radiation varies widely with organism and specific impact considered; these results have implications for biosphere-level damage following astrophysical ionizing radiation events. When considering changes in surface-level visible light irradiance, we found that, contrary to previous assumptions, a decrease in irradiance is only present for a short time in very limited geographical areas; instead we found a net increase for most of the modeled time-space region. This result has implications for proposed climate changes associated with ionizing radiation events. PMID:25692406

  15. Transient Heat Transfer in a Semitransparent Radiating Layer with Boundary Convection and Surface Reflections

    NASA Technical Reports Server (NTRS)

    Siegel, Robert

    1996-01-01

    Surface convection and refractive index are examined during transient radiative heating or cooling of a grey semitransparent layer with internal absorption, emission and conduction. Each side of the layer is exposed to hot or cold radiative surroundings, while each boundary is heated or cooled by convection. Emission within the layer and internal reflections depend on the layer refractive index. The reflected energy and heat conduction distribute energy across the layer and partially equalize the transient temperature distributions. Solutions are given to demonstrate the effect of radiative heating for layers with various optical thicknesses, the behavior of the layer heated by radiation on one side and convectively cooled on the other, and a layer heated by convection while being cooled by radiation. The numerical method is an implicit finite difference procedure with non-uniform space and time increments. The basic method developed in earlier work is expanded to include external convection and incident radiation.

  16. Potential of a New Lunar Surface Radiator Concept for Hot Lunar Thermal Environments

    NASA Technical Reports Server (NTRS)

    Ochoa, Dustin A.; Vogel, Matthew R.; Trevino, Luis A.; Stephan, Ryan A.

    2008-01-01

    The optimum radiator configuration in hot lunar thermal environments is one in which the radiator is parallel to the ground and has no view to the hot lunar surface. However, typical spacecraft configurations have limited real estate available for top-mounted radiators, resulting in a desire to use the spacecraft s vertically oriented sides. Vertically oriented, flat panel radiators will have a large view factor to the lunar surface, and thus will be subjected to significant incident lunar infrared heat. Consequently, radiator fluid temperatures will need to exceed approx.325 K (assuming standard spacecraft radiator optical properties) in order to provide positive heat rejection at lunar noon. Such temperatures are too high for crewed spacecraft applications in which a heat pump is to be avoided. A recent study of vertically oriented radiator configurations subjected to lunar noon thermal environments led to the discovery of a novel radiator concept that yielded positive heat rejection at lower fluid temperatures. This radiator configuration, called the Upright Lunar Terrain Radiator Assembly (ULTRA), has exhibited superior performance to all previously analyzed concepts in terms of heat rejection in the lunar noon thermal environment. A key benefit of the ULTRA is the absence of louvers or other moving parts and its simple geometry. Analysis of the ULTRA for a lunar extravehicular activity (EVA) portable life support system (PLSS) is shown to provide moderate heat rejection, on average, at all solar incident angles assuming an average radiator temperature of 294 K, whereas prior concepts exhibited insignificant heat rejection or heat absorption at higher incident angles. The performance of the ULTRA for a lunar lander is also discussed and compared to the performance of a vertically oriented, flat panel radiator at various lunar latitudes.

  17. Ultrastructural changes on the root surface in "pressure zone" after experimental movement of teeth in young rats fed a low calcium and vitamin D-deficient diet.

    PubMed

    Bielaczyc, A; Gołebiewska, M

    1997-01-01

    Dietary calcium and vitamin D-deficiency, as a potential biological factor in etiopathogenesis of root resorption occurring during orthodontic tooth movement, still remains controversial. The aim of the present investigation was to assess the ultrastructural changes on the surface of the root in "pressure zone" after orthodontic tooth movement in rats fed a low calcium and vitamin D-deficient diet. The studies were carried out on 20 young Wistar rats. The results from the scanning electron microscopic showed the increased root resorption in "pressure zone" after orthodontic tooth movement in rats fed a low calcium and vitamin D-deficient diet.

  18. Numerical simulation of thermocapillary convection at surface modification by impulse laser radiation

    NASA Astrophysics Data System (ADS)

    Popov, V. N.; Kovalev, O. B.; Smirnova, E. M.

    2012-03-01

    Numerical simulation of metal surface alloying with impulse laser radiation has been performed. Impulse intensity influence on melt hydrodynamics and alloying substance distribution has been evaluated. For substance material, the authors used data on iron including dependence of surface tension on melt temperature and admixture concentration.

  19. Landscape pattern change analyses of land surface radiation during the city expansion in Jinan City

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoyan; Gao, Zhiqiang

    2007-09-01

    The issues of urbanization and Land Use / Cover Change (LUCC) are both hot topics in the global change research which are now bound by human survival and development. This article takes the Shandong Jinan City as case study, and analyzing the impact of LUCC on land surface temperature and radiation during the urbanization advancement. This paper uses two periods of multi-temporal Landsat TM/ETM image data, and combining plenty of resources and choosing feasible classification system, and integrating remote sensing and geographic information systems (GIS) for detecting land cover change. We obtain the Land Use / Cover (LUC) maps of Jinan by visual interpretation and the LUC transfer matrix through GIS technique. And then we analyze the causes of LUCC. Retrieve out the land surface temperature and the land surface radiation by using single Landsat TM/ETM 6 thermal infrared data and weather data. We obtain the surface temperature and radiation distribution maps. Considering the transform of LUC, we analyze their impacts on land surface temperature and radiation in the region. Analyzing and describing the space pattern and time change of the impacts of land use and urbanization on land surface temperature and radiation during the past 6 years in Jinan. And provide a foundation to the researches of urbanization process mechanism and environment protection.

  20. Space radiation dose estimates on the surface of Mars

    NASA Astrophysics Data System (ADS)

    Simonsen, Lisa C.; Nealy, John E.; Townsend, Lawrence W.; Wilson, John W.

    1990-08-01

    The Langley cosmic ray transport code and the Langley nucleon transport code (BRYNTRN) are used to quantify the transport and attenuation of galactic cosmic rays (GCR) and solar proton flares through the Martian atmosphere. Surface doses are estimated using both a low density and a high density carbon dioxide model of the atmosphere which, in the vertical direction, provides a total of 16 g/sq cm and 22 g/sq cm of protection, respectively. At the Mars surface during the solar minimum cycle, a blood-forming organ (BFO) dose equivalent of 10.5 to 12 rem/yr due to galactic cosmic ray transport and attenuation is calculated. Estimates of the BFO dose equivalents which would have been incurred from the three large solar flare events of August 1972, November 1960, and February 1956 are also calculated at the surface. Results indicate surface BFO dose equivalents of approximately 2 to 5, 5 to 7, and 8 to 10 rem per event, respectively. Doses are also estimated at altitudes up to 12 km above the Martian surface where the atmosphere will provide less total protection.

  1. Global Aerosol Radiative Forcing using Satellite and Surface Measurements

    NASA Astrophysics Data System (ADS)

    Patadia, F.; Christopher, S. A.

    2007-12-01

    Over the industrial period, aerosols have increased due to human activities and their effects on climate are the largest source of uncertainty in the current IPCC estimates of global climate forcing due to human activities. Inhomogeneous distribution of aerosols in space and time poses a challenge in their characterization and requires global measurements to assess their effects and reduce the associated uncertainties. In this paper we use global measurements from both satellite and ground based observations for one year time period to estimate the shortwave aerosol radiative forcing (SWARF) at the top-of-atmosphere (TOA) and discuss the associated uncertainties. For this, aerosol properties (optical depth) derived from AErosol RObotic NETwork (AERONET), a federation of ground-based remote sensing instruments, are used in this paper in conjunction with measurements of the TOA shortwave flux from CERES instrument (onboard Terra satellite). High spectral and spatial resolution observations from Imager (MODIS) will be used to identify clear sky conditions within CERES foot print and GOCART results will also be used for separating aerosol types. Global aerosol forcing and corresponding radiative forcing efficiencies will be presented as a function of major aerosol types [including anthropogenic (sulfate, soot, black carbon) and natural (dust) aerosols], region and season. This study should serve as a useful constraint for both numerical modeling simulations and satellite based estimates of SWARF.

  2. Global Aerosol Radiative Forcing Using Satellite and Surface Measurements

    NASA Astrophysics Data System (ADS)

    Patadia, F.; Christopher, S. A.

    2008-05-01

    Over the industrial period, aerosols have increased due to human activities and their effects on climate are the largest source of uncertainty in the current IPCC estimates of global climate forcing due to human activities. Inhomogeneous distribution of aerosols in space and time poses a challenge in characterizing their properties and requires global measurements to assess their effects and reduce the associated uncertainties. In this paper we use global measurements from both satellite and ground based observations for one year time period to estimate the shortwave aerosol radiative forcing (SWARF) at the top-of-atmosphere (TOA) and discuss the associated uncertainties. For this, aerosol properties (optical depth) derived from AErosol RObotic NETwork (AERONET), a federation of ground-based remote sensing instruments, are used in this paper in conjunction with measurements of the TOA shortwave flux from CERES instrument (onboard Terra satellite). High spectral and spatial resolution observations from Imager (MODIS) is used to identify clear sky conditions within CERES foot print and GOCART results will also be used for separating aerosol types. Global aerosol forcing and corresponding radiative forcing efficiencies will be presented as a function of major aerosol types [including anthropogenic (sulfate, soot, black carbon) and natural (dust) aerosols], region and season. This study should serve as a useful constraint for both numerical modeling simulations and satellite based estimates of SWARF.

  3. Comparison of Martian Surface Radiation Predictions to the Measurements of Mars Science Laboratory Radiation Assessment Detector (MSL/RAD)

    NASA Astrophysics Data System (ADS)

    Kim, M. H. Y.; Cucinotta, F.; Zeitlin, C. J.; Hassler, D.; Ehresmann, B.; Rafkin, S. C.; Wimmer-Schweingruber, R. F.; Böttcher, S. I.; Boehm, E.; Guo, J.; Kohler, J.; Martin-Garcia, C.; Reitz, G.; Posner, A.

    2014-12-01

    For the analysis of radiation risks to astronauts and planning exploratory space missions, detailed knowledge of particle spectra is an important factor. Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Mars Science Laboratory Radiation Assessment Detector (MSL-RAD) on the Curiosity rover since August 2012, and particle fluxes for a wide range of ion species (up to several hundred MeV/u) and high energy neutrons (8 - 1000 MeV) have been available for the first 200 sols. Although the data obtained on the surface of Mars for 200 sols are limited in the narrow energy spectra, the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code are compared to the data. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used, which includes direct knockout, evaporation and nuclear coalescence. Daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station are implemented into transport calculations for describing the daily column depth of atmosphere. Particles impinging on top of the Martian atmosphere reach the RAD after traversing varying depths of atmosphere that depend on the slant angles, and the model accounts for shielding of the RAD by the rest of the instrument. Calculations of stopping particle spectra are in good agreement with the RAD measurements for the first 200 sols by accounting changing heliospheric conditions and atmospheric pressure. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and thus increase the accuracy of the predictions of future radiation environments on Mars. These contributions lend support to the understanding of radiation health risks to

  4. Comparison of Martian Surface Radiation Predictions to the Measurements of Mars Science Laboratory Radiation Assessment Detector (MSL/RAD)

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Cucinotta, Francis A.; Zeitlin, Cary; Hassler, Donald M.; Ehresmann, Bent; Rafkin, Scot C. R.; Wimmer-Schweingruber, Robert F; Boettcher, Stephan; Boehm, Eckart; Guo, Jingnan; Koehler, Jan; Martin, Cesar; Reitz, Guenther; Posner, Erik

    2014-01-01

    For the analysis of radiation risks to astronauts and planning exploratory space missions, detailed knowledge of particle spectra is an important factor. Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Mars Science Laboratory Radiation Assessment Detector (MSL-RAD) on the Curiosity rover since August 2012, and particle fluxes for a wide range of ion species (up to several hundred MeV/u) and high energy neutrons (8 - 1000 MeV) have been available for the first 200 sols. Although the data obtained on the surface of Mars for 200 sols are limited in the narrow energy spectra, the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code are compared to the data. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used, which includes direct knockout, evaporation and nuclear coalescence. Daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station are implemented into transport calculations for describing the daily column depth of atmosphere. Particles impinging on top of the Martian atmosphere reach the RAD after traversing varying depths of atmosphere that depend on the slant angles, and the model accounts for shielding of the RAD by the rest of the instrument. Calculations of stopping particle spectra are in good agreement with the RAD measurements for the first 200 sols by accounting changing heliospheric conditions and atmospheric pressure. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and thus increase the accuracy of the predictions of future radiation environments on Mars. These contributions lend support to the understanding of radiation health risks to

  5. Experimental study of influence of smooth surface reflectance and diffuse reflectance on estimation of root mean square roughness.

    PubMed

    Mendeleyev, V Ya; Skovorodko, S N

    2011-03-28

    To estimate the root mean square roughness (σ) of a surface from reflected power, it is necessary to know the diffuse reflectance (DR) and the reflectance (SSR) of a smooth surface made from the same material as the rough surface. In our study, σ is estimated from value of power reflected from one-dimensionally rough steel surfaces in the specular direction without considering SSR and DR. An expression describing dependence of an error of the estimation on SSR and DR is derived. Linear polarized light with λ=660 nm and the azimuth of polarization of 49° was used in the experiment. The angle of incidence was varied from 30° to 74°. It was found that absolute relative errors caused by influence of SSR and DR are smaller than 0.03 in the angular ranges of 46-54° and 30-58° for σ=10.2 nm and σ = 49.8 nm, respectively. Out of these ranges, SSR is the main reason for the errors lying in the wide range of ~0.05-2.5.

  6. Spectral emissivity measurements of land-surface materials and related radiative transfer simulations

    NASA Technical Reports Server (NTRS)

    Wan, Z.; Ng, D.; Dozier, J.

    1994-01-01

    Spectral radiance measurements have been made in the laboratory and in the field for deriving spectral emissivities of some land cover samples with a spectroradiometer and an auxiliary radiation source in the wavelength range 2.5-14.5 micrometers. A easy and quick four-step method (four steps to measure the sample and a diffuse reflecting plate surface under sunshine and shadowing conditions, respectively) has been used for simultaneous determination of surface temperature and emissivity. We emphasized in-situ measurements in combination with radiative transfer simulations, and an error analysis for basic assumptions in deriving spectral emissivity of land-surface samples from thermal infrared measurements.

  7. X-ray photoemission analysis of chemically modified TlBr surfaces for improved radiation detectors

    DOE PAGES

    Nelson, A. J.; Voss, L. F.; Beck, P. R.; Graff, R. T.; Conway, A. M.; Nikolic, R. J.; Payne, S. A.; Lee, J. -S.; Kim, H.; Cirignano, L.; et al

    2013-01-12

    We subjected device-grade TlBr to various chemical treatments used in room temperature radiation detector fabrication to determine the resulting surface composition and electronic structure. As-polished TlBr was treated separately with HCl, SOCl2, Br:MeOH and HF solutions. High-resolution photoemission measurements on the valence band electronic structure and Tl 4f, Br 3d, Cl 2p and S 2p core lines were used to evaluate surface chemistry and shallow heterojunction formation. Surface chemistry and valence band electronic structure were correlated with the goal of optimizing the long-term stability and radiation response.

  8. Increased transmission of ultraviolet radiation to the surface due to stratospheric scattering

    SciTech Connect

    Davies, R. )

    1993-04-20

    The author presents calculations which show that stratospheric scattering can result in enhanced ultraviolet transmission to the earths surface through the ozone hole. In general the solar radiation to the earths surface is lower over the Antarctic, even with the ozone hole, because the solar zenith angle is so large. However, in the case with a combined ozone hole, and stratospheric aerosol presence (eg from volcanic activity), then it is possible the ultraviolet radiation reaching the earths surface at high latitudes in the Antarctic can exceed that in the equatorial regions at short wavelengths. The enhancement depends upon large solar zenith angles and absorption optical depth.

  9. Impact of Asian Dust on Global Surface Air Quality and Radiation Budget

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Yu, Hongbin; Ginoux, Paul

    2006-01-01

    Dust originating from Asian deserts and desertification areas can be transported regionally and globally to affect surface air quality, visibility, and radiation budget not only at immediate downwind locations (e.g., eastern Asia) but also regions far away from the sources (e.g., North America). Deposition of Asian dust to the North Pacific Ocean basin influences the ocean productivity. In this study, we will use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, remote sensing data form satellite and from the ground-based network, and in-situ data from aircraft and surface observations to address the following questions: - What are the effects of Asian dust on the surface air quality and visibility over Asia and North America? - What are the seasonal and spatial variations of dust deposition to the North Pacific Ocean? How does the Asian dust affect surface radiation budget?

  10. Studies of the net surface radiative flux from satellite radiances during FIFE

    NASA Technical Reports Server (NTRS)

    Frouin, Robert

    1993-01-01

    Studies of the net surface radiative flux from satellite radiances during First ISLSCP Field Experiment (FIFE) are presented. Topics covered include: radiative transfer model validation; calibration of VISSR and AVHRR solar channels; development and refinement of algorithms to estimate downward solar and terrestrial irradiances at the surface, including photosynthetically available radiation (PAR) and surface albedo; verification of these algorithms using in situ measurements; production of maps of shortwave irradiance, surface albedo, and related products; analysis of the temporal variability of shortwave irradiance over the FIFE site; development of a spectroscopy technique to estimate atmospheric total water vapor amount; and study of optimum linear combinations of visible and near-infrared reflectances for estimating the fraction of PAR absorbed by plants.

  11. Radiation magnetohydrodynamic simulation of plasma formed on a surface by a megagauss field

    NASA Astrophysics Data System (ADS)

    Esaulov, A. A.; Bauer, B. S.; Makhin, V.; Siemon, R. E.; Lindemuth, I. R.; Awe, T. J.; Reinovsky, R. E.; Struve, K. W.; Desjarlais, M. P.; Mehlhorn, T. A.

    2008-03-01

    Radiation magnetohydrodynamic modeling is used to study the plasma formed on the surface of a cylindrical metallic load, driven by megagauss magnetic field at the 1MA Zebra generator (University of Nevada, Reno). An ionized aluminum plasma is used to represent the “core-corona” behavior in which a heterogeneous Z -pinch consists of a hot low-density corona surrounding a dense low-temperature core. The radiation dynamics model included simultaneously a self-consistent treatment of both the opaque and transparent plasma regions in a corona. For the parameters of this experiment, the boundary of the opaque plasma region emits the major radiation power with Planckian black-body spectrum in the extreme ultraviolet corresponding to an equilibrium temperature of 16eV . The radiation heat transport significantly exceeds the electron and ion kinetic heat transport in the outer layers of the opaque plasma. Electromagnetic field energy is partly radiated (13%) and partly deposited into inner corona and core regions (87%). Surface temperature estimates are sensitive to the radiation effects, but the surface motion in response to pressure and magnetic forces is not. The general results of the present investigation are applicable to the liner compression experiments at multi-MA long-pulse current accelerators such as Atlas and Shiva Star. Also the radiation magnetohydrodynamic model discussed in the paper may be useful for understanding key effects of wire array implosion dynamics.

  12. Radiation magnetohydrodynamic simulation of plasma formed on a surface by a megagauss field.

    PubMed

    Esaulov, A A; Bauer, B S; Makhin, V; Siemon, R E; Lindemuth, I R; Awe, T J; Reinovsky, R E; Struve, K W; Desjarlais, M P; Mehlhorn, T A

    2008-03-01

    Radiation magnetohydrodynamic modeling is used to study the plasma formed on the surface of a cylindrical metallic load, driven by megagauss magnetic field at the 1MA Zebra generator (University of Nevada, Reno). An ionized aluminum plasma is used to represent the "core-corona" behavior in which a heterogeneous Z-pinch consists of a hot low-density corona surrounding a dense low-temperature core. The radiation dynamics model included simultaneously a self-consistent treatment of both the opaque and transparent plasma regions in a corona. For the parameters of this experiment, the boundary of the opaque plasma region emits the major radiation power with Planckian black-body spectrum in the extreme ultraviolet corresponding to an equilibrium temperature of 16 eV. The radiation heat transport significantly exceeds the electron and ion kinetic heat transport in the outer layers of the opaque plasma. Electromagnetic field energy is partly radiated (13%) and partly deposited into inner corona and core regions (87%). Surface temperature estimates are sensitive to the radiation effects, but the surface motion in response to pressure and magnetic forces is not. The general results of the present investigation are applicable to the liner compression experiments at multi-MA long-pulse current accelerators such as Atlas and Shiva Star. Also the radiation magnetohydrodynamic model discussed in the paper may be useful for understanding key effects of wire array implosion dynamics.

  13. The Impact of Cloud Type on Surface Radiation and Road Pavement Temperature

    NASA Astrophysics Data System (ADS)

    Walker, C. L.; Anderson, A.; Chapman, M.; Drobot, S.

    2012-12-01

    Forecast systems provide decision support for end-users ranging from the solar energy industry to municipalities concerned with winter road maintenance. The racing community also relies on racetrack pavement temperature forecast systems because tire friction decreases as temperature increases, affecting vehicle performance. Race crews perform vehicle maintenance (e.g., tire pressure and suspension adjustments) to maximize traction given a forecasted racetrack temperature. Many forecast systems suffer from inaccurate radiation forecasts resulting in part from a lack of information relating radiation to cloud types. This research seeks to improve the forecasts by determining how cloud type impacts the amount of solar radiation reaching the surface. Cloud type information was obtained from the Naval Research Laboratory Cloud Classifier algorithm and radiation data were obtained from a Davis Weather Station. A theoretical maximum solar radiation distribution was calculated. Cloud type-radiation distribution analyses from Salisbury, North Carolina during May-June 2012 indicated that low clouds allowed approximately 20% of the maximum possible radiation to reach the surface, mid level clouds 32%, high clouds 40% and cumuliform types 34%. A categorical regression analysis revealed 33% of the variation in solar radiation on cloudy case days can be explained by cloud type. Inclusion of clear case days with apparent variability lowered this to 7% suggesting another influence on radiation. A similar bulk statistical analysis is in progress on a much larger data set obtained from the Oklahoma Mesonet. This work lays the foundation for use of satellite cloud type information in order to improve the output of forecast systems. Distribution of mean solar radiation measured at the surface for all nine case studies, sorted by cloud type height characteristics, where n represents the sample size.

  14. An Improved Algorithm for Retrieving Surface Downwelling Longwave Radiation from Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Zhou, Yaping; Kratz, David P.; Wilber, Anne C.; Gupta, Shashi K.; Cess, Robert D.

    2006-01-01

    Retrieving surface longwave radiation from space has been a difficult task since the surface downwelling longwave radiation (SDLW) are integrations from radiation emitted by the entire atmosphere, while those emitted from the upper atmosphere are absorbed before reaching the surface. It is particularly problematic when thick clouds are present since thick clouds will virtually block all the longwave radiation from above, while satellites observe atmosphere emissions mostly from above the clouds. Zhou and Cess developed an algorithm for retrieving SDLW based upon detailed studies using radiative transfer model calculations and surface radiometric measurements. Their algorithm linked clear sky SDLW with surface upwelling longwave flux and column precipitable water vapor. For cloudy sky cases, they used cloud liquid water path as an additional parameter to account for the effects of clouds. Despite the simplicity of their algorithm, it performed very well for most geographical regions except for those regions where the atmospheric conditions near the surface tend to be extremely cold and dry. Systematic errors were also found for areas that were covered with ice clouds. An improved version of the algorithm was developed that prevents the large errors in the SDLW at low water vapor amounts. The new algorithm also utilizes cloud fraction and cloud liquid and ice water paths measured from the Cloud and the Earth's Radiant Energy System (CERES) satellites to separately compute the clear and cloudy portions of the fluxes. The new algorithm has been validated against surface measurements at 29 stations around the globe for the Terra and Aqua satellites. The results show significant improvement over the original version. The revised Zhou-Cess algorithm is also slightly better or comparable to more sophisticated algorithms currently implemented in the CERES processing. It will be incorporated in the CERES project as one of the empirical surface radiation algorithms.

  15. Influence of snow cover changes on surface radiation and heat balance based on the WRF model

    NASA Astrophysics Data System (ADS)

    Yu, Lingxue; Liu, Tingxiang; Bu, Kun; Yang, Jiuchun; Chang, Liping; Zhang, Shuwen

    2016-07-01

    The snow cover extent in mid-high latitude areas of the Northern Hemisphere has significantly declined corresponding to the global warming, especially since the 1970s. Snow-climate feedbacks play a critical role in regulating the global radiation balance and influencing surface heat flux exchange. However, the degree to which snow cover changes affect the radiation budget and energy balance on a regional scale and the difference between snow-climate and land use/cover change (LUCC)-climate feedbacks have been rarely studied. In this paper, we selected Heilongjiang Basin, where the snow cover has changed obviously, as our study area and used the WRF model to simulate the influences of snow cover changes on the surface radiation budget and heat balance. In the scenario simulation, the localized surface parameter data improved the accuracy by 10 % compared with the control group. The spatial and temporal analysis of the surface variables showed that the net surface radiation, sensible heat flux, Bowen ratio, temperature and percentage of snow cover were negatively correlated and that the ground heat flux and latent heat flux were positively correlated with the percentage of snow cover. The spatial analysis also showed that a significant relationship existed between the surface variables and land cover types, which was not obviously as that for snow cover changes. Finally, six typical study areas were selected to quantitatively analyse the influence of land cover types beneath the snow cover on heat absorption and transfer, which showed that when the land was snow covered, the conversion of forest to farmland can dramatically influence the net radiation and other surface variables, whereas the snow-free land showed significantly reduced influence. Furthermore, compared with typical land cover changes, e.g., the conversion of forest into farmland, the influence of snow cover changes on net radiation and sensible heat flux were 60 % higher than that of land cover changes

  16. Ultraviolet radiation effects on fruit surface respiration and chlorophyll fluorescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-value fruit crops are exposed to a range of environmental conditions that can reduce fruit quality. Solar injury (SI) or sunburn is a common disorder in tropical, subtropical and temperate climates and is related to: 1) high fruit surface temperature, 2) high visible light intensity, and 3) ul...

  17. Waveguide-coupled directional Raman radiation for surface analysis.

    PubMed

    Chen, Chen; Li, Jin-Yang; Wang, Li; Lu, Dan-Feng; Qi, Zhi-Mei

    2015-09-01

    Kretschmann-type waveguide structures, including Plasmon Waveguide (PW) and Resonant Mirror (RM), have been applied in interfacial Raman spectroscopy due to the following unique features: (1) unlike the classic surface enhanced Raman scattering (SERS) substrates made of either gold or silver, both PW and RM can be prepared using a large variety of inexpensive materials; (2) the field enhancement factors using these structures can be theoretically predicted and experimentally controlled, which enables us to manipulate the surface Raman sensitivity with high repeatability; (3) the use of transverse electric (TE) and transverse magnetic (TM) modes for Raman excitation allows us to evaluate the orientation of target molecules immobilized on the waveguide surface; (4) the unwanted impact of noble metals on the Raman fingerprints of target molecules, which is often observed for conventional SERS substrates, can be avoided upon the use of dielectric waveguides. In this paper, guided-mode-coupled directional Raman emission, which is an additional important feature of the waveguide Raman technique, was theoretically investigated based on the optical reciprocity theorem combined with the Fresnel equations. The simulation results indicate that the directional Raman emission from a dipole located within the field confinement and penetration depth of a guided mode depends on both the orientation of the dipole and its distance from the waveguide surface. Raman light from the TE-oriented dipoles is launched into the prism coupler at the TE-mode resonance angle and that from the non-TE-oriented dipoles propagates at the TM-mode resonance angle. The intensity of the guided-mode-excited Raman signal propagating at the mode resonance angle is proportional to the fourth power of the mode field (E(4)) at the depth of the dipole from the waveguide surface. This means that the guided-mode-excited and guided-mode-coupled directional Raman spectroscopy has a detection depth that is as

  18. A Radiation Dosimeter Concept for the Lunar Surface Environment

    NASA Technical Reports Server (NTRS)

    Adams, James H.; Christl, Mark J.; Watts, John; Kuznetsov, Eugeny N.; Parnell, Thomas A.; Pendleton, Geoff N.

    2007-01-01

    A novel silicon detector configuration for radiation dose measurements in an environment where solar energetic particles are of most concern is described. The dosimeter would also measure the dose from galactic cosmic rays. In the lunar environment a large range in particle flux and ionization density must be measured and converted to dose equivalent. This could be accomplished with a thick (e.g. 2mm) silicon detector segmented into cubic volume elements "voxels" followed by a second, thin monolithic silicon detector. The electronics needed to implement this detector concept include analog signal processors (ASIC) and a field programmable gate array (FPGA) for data accumulation and conversion to linear energy transfer (LET) spectra and to dose-equivalent (Sievert). Currently available commercial ASIC's and FPGA's are suitable for implementing the analog and digital systems.

  19. The radiation refinement of polystyrene surface applied in immunoanalysis

    NASA Astrophysics Data System (ADS)

    Pipota, J.; Plaček, V.; Vacek, K.; Burianová, T.

    1993-10-01

    Polystyrene, material frequently used for ELISA microtiter plates, was modified by gamma irradiation in order to enhance the passive absorption binding capacity of immunoglobuline E. The dependences of this capacity increase on dose and irradiation conditions (atmosphere, presence of water) permitted the optimization this treatment of plates up to the technological scale. However the increase of passive absorption in the case of low-molecular weight synthetic peptides, such as anti-EBNA, was not sufficient and the reason for this remains to be clarified. Radiation grafting made it possible to fix the hydrazide functional group onto the polysterene. It offers the possibility to of binding the proteins, via covalent linkage, with the carbonyl group formed by the oxidation of carbohydrates included in the protein molecule.

  20. Improvement in Clouds and the Earth's Radiant Energy System/Surface and Atmosphere Radiation Budget Dust Aerosol Properties, Effects on Surface Validation of Clouds and Radiative Swath

    SciTech Connect

    Rutan, D.; Rose, F.; Charlock, T.P.

    2005-03-18

    Within the Clouds and the Earth's Radiant Energy System (CERES) science team (Wielicki et al. 1996), the Surface and Atmospheric Radiation Budget (SARB) group is tasked with calculating vertical profiles of heating rates, globally, and continuously, beneath CERES footprint observations of Top of Atmosphere (TOA) fluxes. This is accomplished using a fast radiative transfer code originally developed by Qiang Fu and Kuo-Nan Liou (Fu and Liou 1993) and subsequently highly modified by the SARB team. Details on the code and its inputs can be found in Kato et al. (2005) and Rose and Charlock (2002). Among the many required inputs is characterization of the vertical column profile of aerosols beneath each footprint. To do this SARB combines aerosol optical depth information from the moderate-resolution imaging spectroradiometer (MODIS) instrument along with aerosol constituents specified by the Model for Atmosphere and Chemical Transport (MATCH) of Collins et al. (2001), and aerosol properties (e.g. single scatter albedo and asymmetry parameter) from Tegen and Lacis (1996) and OPAC (Hess et al. 1998). The publicly available files that include these flux profiles, called the Clouds and Radiative Swath (CRS) data product, available from the Langley Atmospheric Sciences Data Center (http://eosweb.larc.nasa.gov/). As various versions of the code are completed, publishable results are named ''Editions.'' After CRS Edition 2A was finalized it was found that dust aerosols were too absorptive. Dust aerosols have subsequently been modified using a new set of properties developed by Andy Lacis and results have been released in CRS Edition 2B. This paper discusses the effects of changing desert dust aerosol properties, which can be significant for the radiation budget in mid ocean, a few thousand kilometers from the source regions. Resulting changes are validated via comparison of surface observed fluxes from the Saudi Solar Village surface site (Myers et al. 1999), and the E13 site

  1. Radiation Environment and Surface Radiolytic Interactions at Mimas

    NASA Technical Reports Server (NTRS)

    Cooper, J. F.; Sittler, E. C.; Lipatov, A. S.; Sturner, S. J.; Paranicas, C.; Cooper, P. D.

    2010-01-01

    Saturn's innermost principal moon Mimas shares the distinction with Europa at Jupiter of being the most irradiated icy moon in its respective planetary system, although the energetic electron energy flux at Mimas is forty times smaller than at Europa. High energy (> 10 MeV) proton fluxes are low in this moon's orbital corridor, likely since slowly diffusing protons from the weak but steady source of cosmic ray albedo neutron decay (CRAND) cannot accumulate without impacting the moon surface. Lower energy proton fluxes are also evidently suppressed in this orbital region. Plasma ion and electron fluxes are also low apparently due to cooling by interaction with E-ring dust and neutral gas from Enceladus. Due to energy-dependent effects of longitudinal gradient-curvature drift for the electrons, the trailing hemisphere is mainly irradiated by electrons at energies below 1 MeV that drift relative to Mimas in the prograde direction of orbital motion around Saturn, while higher energy electrons primarily impact the leading hemisphere. Plasma ions in the inner magnetosphere of Saturn are mainly pickup ions forming from the dissociation products of Enceladus plume water molecules, additionally including some contribution from photosputtering of the main rings, and do not introduce new elemental materials at Mimas via surface implantation from the corotating plasma. Thus the primary interaction at the surface is radiolytic chemistry induced in pure water ice by relatively deep penetration of the energetic electrons to millimeter and greater depths, as compared to the micron depths impacted by the corotating plasma ions. If surface erosion by sputtering from relatively low fluxes of the plasma and more energetic ions is indeed ineffective, then molecular products (OH, H2O2, 02, 03) of the radiolytic interactions may accumulate in the meters-deep impact regolith of the surface ices. An effect of regolith trapped gas accumulation could be to increase porosity and reduce

  2. Radiation Environment and Surface Radiolytic Interactions at Mimas

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.; Sittler, E. C.; Lipatov, A. S.; Sturner, S. J.; Paranicas, C.; Cooper, P. D.

    2010-12-01

    Saturn’s innermost principal moon Mimas shares the distinction with Europa at Jupiter of being the most irradiated icy moon in its respective planetary system, although the energetic electron energy flux at Mimas is forty times smaller than at Europa. High energy (> 10 MeV) proton fluxes are low in this moon’s orbital corridor, likely since slowly diffusing protons from the weak but steady source of cosmic ray albedo neutron decay (CRAND) cannot accumulate without impacting the moon surface. Lower energy proton fluxes are also evidently suppressed in this orbital region. Plasma ion and electron fluxes are also low apparently due to cooling by interaction with E-ring dust and neutral gas from Enceladus. Due to energy-dependent effects of longitudinal gradient-curvature drift for the electrons, the trailing hemisphere is mainly irradiated by electrons at energies below 1 MeV that drift relative to Mimas in the prograde direction of orbital motion around Saturn, while higher energy electrons primarily impact the leading hemisphere. Plasma ions in the inner magnetosphere of Saturn are mainly pickup ions forming from the dissociation products of Enceladus plume water molecules, additionally including some contribution from photosputtering of the main rings, and do not introduce new elemental materials at Mimas via surface implantation from the corotating plasma. Thus the primary interaction at the surface is radiolytic chemistry induced in pure water ice by relatively deep penetration of the energetic electrons to millimeter and greater depths, as compared to the micron depths impacted by the corotating plasma ions. If surface erosion by sputtering from relatively low fluxes of the plasma and more energetic ions is indeed ineffective, then molecular products (OH, H2O2, O2, O3) of the radiolytic interactions may accumulate in the meters-deep impact regolith of the surface ices. An effect of regolith trapped gas accumulation could be to increase porosity and reduce

  3. Survey of surface roughness properties of synchrotron radiation optics

    SciTech Connect

    Takacs, P.Z.; Colbert, J.; Church, E.L.

    1986-03-01

    Measurements of surface roughness were made on a large number of grazing incidence mirrors delivered for use at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The measurements were made with a WYKO optical profiler using a 2.5X and a 10X objective and analyzed with our PROFILE code to generate an average periodogram representation for each surface. The data is presented in the form of representative profiles with all of the periodogram curves arranged according to figure type. Analysis of the periodograms allows one to compute bandwidth-limited values for RMS roughness and slope, to provide valuable feedback information to manufacturers regarding compliance with specifications, and to predict the performance of the optic at x-ray wavelengths.

  4. Terahertz radiation from bismuth surface induced by femtosecond laser pulses.

    PubMed

    Ilyakov, I E; Shishkin, B V; Fadeev, D A; Oladyshkin, I V; Chernov, V V; Okhapkin, A I; Yunin, P A; Mironov, V A; Akhmedzhanov, R A

    2016-09-15

    We report on the first experimental observation of terahertz (THz) wave generation from bismuth mono- and polycrystalline samples irradiated by femtosecond laser pulses. Dependencies of the THz signal on the crystal orientation, optical pulse energy, incidence angle, and polarization are presented and discussed together with features of the sample surfaces. The optical-to-THz conversion efficiency was up to two orders of magnitude higher than for metal at a moderate fluence of ∼1  mJ/cm2. We also found nonlinear effects not previously observed using other metal and semiconductor materials: (a) asymmetry of THz response with respect to a half-turn of a sample around its normal, (b) THz polarization control by orientation of the sample surface, and PMID:27628379

  5. XUV metrology: surface analysis with extreme ultraviolet radiation

    NASA Astrophysics Data System (ADS)

    Banyay, M.; Juschkin, L.; Bücker, T.; Loosen, P.; Bayer, A.; Barkusky, F.; Döring, S.; Peth, C.; Mann, K.; Blaschke, H.; Balasa, I.; Ristau, D.

    2009-05-01

    The utilization of nanostructured materials for modern applications gained more and more importance during the last few years. As examples super-fluorescent quantum dots, the use of carbon nano tubes (CNTs) in microelectronics, electrospun fibers in filter membranes, thin film coatings for solar cells, mirrors or LEDs, semiconductor electronics, and functionalized surfaces may be named to address only a few topics. To optimize the systems and enable the full range of capabilities of nanostructures a thorough characterization of the surface-near topography (e.g. roughness, thickness, lateral dimension) as well as of the chemical composition is essential. As a versatile tool for spatial and chemical characterization XUV reflectometry, scatterometry and diffractometry is proposed. Three different experimental setups have been realized evaluating spectral resolved reflectance under constant incidence angle, angular resolved reflectance at a constant wavelength, or a combined approach using laboratory scaled XUV sources to gain insight into chemical composition, film thickness and surface/interface roughness. Experiments on near-edge X-ray absorption fine structure spectroscopy (NEXAFS) at the carbon K-edge have been performed. The investigated systems range from synthetic polymers (PMMA, PI) over organic substances (humic acids) to biological matter (lipids), delivering unique spectra for each compound. Thus NEXAFS spectroscopy using a table-top XUV source could be established as a highly surface sensitive fingerprint method for chemical analysis. Future extended experiments will investigate the silicon L-edge where e.g. silicon oxide interlayers below high-k or other nano-layered material on Sisubstrates depict a technological important group of composite systems.

  6. The SMAP level 4 surface and root zone soil moisture data assimilation product

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The NASA Soil Moisture Active Passive (SMAP) mission is scheduled for launch in January 2015 and will provide L-band radar and radiometer observations that are sensitive to surface soil moisture (in the top few centimeters of the soil column). For several of the key applications targeted by SMAP, ho...

  7. Genomic diversity of Pseudomonas spp. isolated from aerial or root surfaces of plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among the diverse strains of Pseudomonas fluorescens and Pseudomonas chlororaphis inhabiting plant surfaces are those that protect plants from infection by pathogens. To explore the diversity of these bacteria, we derived genomic sequences of seven strains that suppress plant disease. Along with t...

  8. The SMAP Level 4 surface and root-zone soil moisture product

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Slated for launch in 2015, the NASA Soil Moisture Active/Passive mission represents a generational advance in our ability to globally observe time and space variations in surface soil moisture fields. The SMAP mission concept is based on the integrated use of L-band active radar and passive radiome...

  9. Radiation damage from single heavy ion impacts on metal surfaces

    SciTech Connect

    Donnelly, S.E.; Birtcher, R.C.

    1998-06-01

    The effects of single ion impacts on the surfaces of films of Au, Ag, In and Pb have been studied using in-situ transmission electron microscopy. On all of these materials, individual ion impacts produce surface craters, in some cases, with associated expelled material. The cratering efficiency scales with the density of the irradiated metal. For very thin Au foils ({approx} 20--50 nm), in some cases individual ions are seen to punch small holes completely through the foil. Continued irradiation results in a thickening of the foil. The process giving rise to crater and hole formation and other changes observed in the thin foils has been found to be due to pulsed localized flow--i.e. melting and flow due to the thermal spikes arising from individual ion impacts. Experiments carried out on thin films of silver sandwiched between SiO{sub 2} layers have indicated that pulsed localized flow also occurs in this system and contributes to the formation of Ag nanoclusters in SiO{sub 2}--a system of interest for its non-linear optical properties. Calculation indicates that, when ion-induced, collision cascades occur near surfaces (within {approx} 5 nm) with energy densities sufficient to cause melting, craters are formed. Crater formation occurs as a result of the explosive outflow of material from the hot molten core of the cascade. Processes occurring in the sandwiched layer are less well understood.

  10. Performances study of UWB monopole antennas using half-elliptic radiator conformed on elliptical surface

    NASA Astrophysics Data System (ADS)

    Djidel, S.; Bouamar, M.; Khedrouche, D.

    2016-04-01

    This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.

  11. Plasma formation on a metal surface under combined action of laser and microwave radiation

    SciTech Connect

    Gavrilyuk, A P; Shaparev, N Ya

    2013-10-31

    By means of numerical modelling of the combined effect of laser (1.06 mm) and microwave (10{sup 10} – 10{sup 13} s{sup -1}) radiation on the aluminium surface in vacuum it is shown that the additional action of microwave radiation with the frequency 10{sup 12} s{sup -1} provides complete ionisation of the metal vapour (for the values of laser radiation duration and intensity used in the calculations), while in the absence of microwave radiation the vapour remains weakly ionised. The mathematical model used accounts for the processes, occurring in the condensed phase (heat conduction, melting), the evaporation and the kinetic processes in the resulting vapour. (interaction of laser radiation with matter. laser plasma)

  12. "Intelligent Ensemble" Projections of Precipitation and Surface Radiation in Support of Agricultural Climate Change Adaptation

    NASA Technical Reports Server (NTRS)

    Taylor, Patrick C.; Baker, Noel C.

    2015-01-01

    Earth's climate is changing and will continue to change into the foreseeable future. Expected changes in the climatological distribution of precipitation, surface temperature, and surface solar radiation will significantly impact agriculture. Adaptation strategies are, therefore, required to reduce the agricultural impacts of climate change. Climate change projections of precipitation, surface temperature, and surface solar radiation distributions are necessary input for adaption planning studies. These projections are conventionally constructed from an ensemble of climate model simulations (e.g., the Coupled Model Intercomparison Project 5 (CMIP5)) as an equal weighted average, one model one vote. Each climate model, however, represents the array of climate-relevant physical processes with varying degrees of fidelity influencing the projection of individual climate variables differently. Presented here is a new approach, termed the "Intelligent Ensemble, that constructs climate variable projections by weighting each model according to its ability to represent key physical processes, e.g., precipitation probability distribution. This approach provides added value over the equal weighted average method. Physical process metrics applied in the "Intelligent Ensemble" method are created using a combination of NASA and NOAA satellite and surface-based cloud, radiation, temperature, and precipitation data sets. The "Intelligent Ensemble" method is applied to the RCP4.5 and RCP8.5 anthropogenic climate forcing simulations within the CMIP5 archive to develop a set of climate change scenarios for precipitation, temperature, and surface solar radiation in each USDA Farm Resource Region for use in climate change adaptation studies.

  13. Radiation Heat Transfer Between Diffuse-Gray Surfaces Using Higher Order Finite Elements

    NASA Technical Reports Server (NTRS)

    Gould, Dana C.

    2000-01-01

    This paper presents recent work on developing methods for analyzing radiation heat transfer between diffuse-gray surfaces using p-version finite elements. The work was motivated by a thermal analysis of a High Speed Civil Transport (HSCT) wing structure which showed the importance of radiation heat transfer throughout the structure. The analysis also showed that refining the finite element mesh to accurately capture the temperature distribution on the internal structure led to very large meshes with unacceptably long execution times. Traditional methods for calculating surface-to-surface radiation are based on assumptions that are not appropriate for p-version finite elements. Two methods for determining internal radiation heat transfer are developed for one and two-dimensional p-version finite elements. In the first method, higher-order elements are divided into a number of sub-elements. Traditional methods are used to determine radiation heat flux along each sub-element and then mapped back to the parent element. In the second method, the radiation heat transfer equations are numerically integrated over the higher-order element. Comparisons with analytical solutions show that the integration scheme is generally more accurate than the sub-element method. Comparison to results from traditional finite elements shows that significant reduction in the number of elements in the mesh is possible using higher-order (p-version) finite elements.

  14. Radiative surface temperatures of the burned and unburned areas in a tallgrass prairie

    NASA Technical Reports Server (NTRS)

    Asrar, G.; Harris, T. R.; Lapitan, R. L.; Cooper, D. I.

    1988-01-01

    This study was conducted in a natural tallgrass prairie area in the Flint Hills of Kansas. The objective was to evaluate the surface radiative temperatures of burned and unburned treatments of the grassland as a means of delineating the areas covered by each treatment. Burning is used to remove the senescent vegetation resulting from the previous year's growth. Surface temperatures were obtained in situ and by an airborne scanner. Burned and unburned grass canopies had distinctly different diurnal surface radiative temperatures. Measurements of surface energy balance components revealed a difference in partitioning of the available energy between the two canopies, which resulted in the difference in their measured surface temperatures. The magnitude of this difference is dependent on the time of measurements and topographic conditions.

  15. Surface modification of dental tissues by KrF excimer laser radiation

    NASA Astrophysics Data System (ADS)

    Sivakumar, M.; Oliveira, V.; Vilar, R.

    2007-02-01

    Laser treatment is a promising technique for dental applications such as caries removal, dental hypersensitivity reduction and improvement of the bond strength between dentin and restoration materials. In this study the topographic and morphological changes induced in enamel and dentin surfaces by treating with KrF excimer laser radiation were studied as a function of the number of laser pulses and radiation fluence by scanning electron microscopy and optical profilometry. For enamel, independently of the fluence used, material removal occurs preferentially at the prisms sheaths, leading to the formation of surface pits of a few micrometers. For dentin, a cone-like topography develops when the tubules are approximately parallel to the laser beam direction and the radiation fluence is within the range 0.5 to 1.5 J/cm2. For higher fluences, the treated surfaces are flat and covered with a layer of re-solidified materials.

  16. Modeling the spectrum of infrasonic hydroacoustic radiation generated by the sea surface under storm conditions

    NASA Astrophysics Data System (ADS)

    Zapevalov, A. S.; Pokazeev, K. V.

    2016-09-01

    Generation of infrasonic radiation into a water medium by sea surface waves is analyzed. The analysis is carried out for the situation in which the infrasound is generated by surface waves with frequencies close to those of dominant waves. The presence of two wave systems on the sea surface is assumed: swell and wind waves. It is shown that if the frequencies of spectral peaks of wind waves and swell diverge by 20%, the maximum value of the radiation spectrum decreases by approximately 40% (if the general directions of the two wave systems are oriented strictly towards each other). A deviation of the general directions of the two wave systems from the opposite direction by 45° leads to a decrease in the maximum value of the radiation spectrum by more than two times.

  17. Assessment of Satellite Surface Radiation Products in Highland Regions with Tibet Instrumental Data

    NASA Technical Reports Server (NTRS)

    Yang, Kun; Koike, Toshio; Stackhouse, Paul; Mikovitz, Colleen

    2006-01-01

    This study presents results of comparisons between instrumental radiation data in the elevated Tibetan Plateau and two global satellite products: the Global Energy and Water Cycle Experiment - Surface Radiation Budget (GEWEX-SRB) and International Satellite Cloud Climatology Project - Flux Data (ISCCP-FD). In general, shortwave radiation (SW) is estimated better by ISCCP-FD while longwave radiation (LW) is estimated better by GEWEX-SRB, but all the radiation components in both products are under-estimated. Severe and systematic errors were found in monthly-mean SRB SW (on plateau-average, -48 W/sq m for downward SW and -18 W/sq m for upward SW) and FD LW (on plateau-average, -37 W/sq m for downward LW and -62 W/sq m for upward LW) for radiation. Errors in monthly-mean diurnal variations are even larger than the monthly mean errors. Though the LW errors can be reduced about 10 W/sq m after a correction for altitude difference between the site and SRB and FD grids, these errors are still higher than that for other regions. The large errors in SRB SW was mainly due to a processing mistake for elevation effect, but the errors in SRB LW was mainly due to significant errors in input data. We suggest reprocessing satellite surface radiation budget data, at least for highland areas like Tibet.

  18. Surface and aerosol models for use in radiative transfer codes

    NASA Astrophysics Data System (ADS)

    Hart, Quinn J.

    1991-08-01

    Absolute reflectance-based radiometric calibrations of Landsat-5 Thematic Mapper (TM) are improved with the inclusion of a method to invert optical-depth measurements to obtain aerosol-particle size distributions, and a non-Lambertian surface reflectance model. The inverted size distributions can predict radiances varying from the previously assumed jungian distributions by as much as 5 percent, though the reduction in the estimated error is less than one percent. Comparison with measured diffuse-to-global ratios show that neither distribution consistently predicts the ratio accurately, and this is shown to be a large contributor to calibration uncertainties. An empirical model for the surface reflectance of White Sands, using a two-degree polynomial fit as a function of scattering angle, was employed. The model reduced estimated errors in radiance predictions by up to one percent. Satellite calibrations dating from October, 1984 were reprocessed using the improved methods and linear estimations of satellite counts per unit radiance versus time since launch were determined which showed a decrease over time for the first four bands.

  19. Alteration in the inherent metallic and surface properties of nickel-titanium root canal instruments to enhance performance, durability and safety: a focused review.

    PubMed

    Gutmann, J L; Gao, Y

    2012-02-01

    The expanded use of nickel-titanium (NiTi) rotary instruments in root canal procedures has led to the development of a wide variety of shapes, designs and applications. Root canal anatomy has not changed, however, and the same challenges exist in both initial treatment and the revision of unacceptable treatment. These challenges include application with high levels of achievement and low to no levels of adverse effects, such as instrument fracture, root canal wall ledging, dentine wall perforation and so forth. To that end, many manufacturers have been seeking ways to alter the presently available and wide range of root canal instrument designs, with a focus on altering the surface of the alloy or altering the alloy microstructure with post-machining or post-twisting heat treatment. This focused review will address the impact that these modifications have had on instrument flexibility, resistance to cyclic fatigue and cutting efficiency.

  20. Surface characterization of gallium nitride modified with peptides before and after exposure to ionizing radiation in solution.

    PubMed

    Berg, Nora G; Nolan, Michael W; Paskova, Tania; Ivanisevic, Albena

    2014-12-30

    An aqueous surface modification of gallium nitride was employed to attach biomolecules to the surface. The modification was a simple two-step process using a single linker molecule and mild temperatures. The presence of the peptide on the surface was confirmed with X-ray photoelectron spectroscopy. Subsequently, the samples were placed in water baths and exposed to ionizing radiation to examine the effects of the radiation on the material in an environment similar to the body. Surface analysis confirmed degradation of the surface of GaN after radiation exposure in water; however, the peptide molecules successfully remained on the surface following exposure to ionizing radiation. We hypothesize that during radiation exposure of the samples, the radiolysis of water produces peroxide and other reactive species on the sample surface. Peroxide exposure promotes the formation of a more stable layer of gallium oxyhydroxide which passivates the surface better than other oxide species.

  1. A Review of Textured Surfaces, Paints, and Coatings for Space Radiator Applications

    NASA Astrophysics Data System (ADS)

    Jaworske, Donald A.

    2004-02-01

    Future space nuclear power systems will require large radiators to dissipate excess thermal energy. Such radiators may be composed of carbon-carbon composite fins made from high thermal conductivity graphite fibers or may be a more traditional honeycomb structure with face sheets composed of a suitable high temperature metal. In either case, the surface of the radiator must have a high emittance at the desired operating temperature, envisioned to be in the range of 400 to 900 K, and must be durable for the length of the mission, envisioned to be ten years. Existing thermal control paints and coatings may be applicable at the low end of the envisioned temperature range, but may not be applicable at elevated temperatures. Hence, other avenues of emittance enhancement need to be explored. Previous work has identified a number of promising technologies that may be useful for enhancing the emittance of candidate surfaces, including texturing the radiator surface via sand blasting, oxidation at elevated temperature, and exposure to atomic oxygen. This paper will review existing candidate thermal control paints and coatings to identify their strengths and weaknesses and will review other promising technologies that have been proposed in the past few years to enhance the emittance of radiator surfaces.

  2. Complete trapping of electromagnetic radiation using surface magnetoplasmons.

    PubMed

    Shen, Linfang; Wang, Zhuoyuan; Deng, Xiaohua; Wu, Jin-Jei; Yang, Tzong-Jer

    2015-04-15

    Because the dispersion properties of surface magnetoplasmons (SMPs) in a magnetized plasmonic material closely depend on its cladding dielectric, it is possible to completely trap SMPs in a system consisting of a plasmonic material with cladding of a dielectric heterostructure. By using a semiconductor, our finite element simulation (performed using the software COMSOL) shows that terahertz one-way SMPs in such a system can be completely trapped at the interface of the heterostructure and hence, a focused subwavelength-scale hotspot with dramatically enhanced field is generated. Moreover, a one-way SMP pulse in this system can also be completely trapped, and the wave packet can be compressed into a stable hotspot on the subwavelength scale. PMID:25872091

  3. Variation of solar cell sensitivity and solar radiation on tilted surfaces

    NASA Technical Reports Server (NTRS)

    Klucher, T. M.

    1978-01-01

    The validity is studied that one of various insolation models used to compute solar radiation incident on tilted surfaces from global data measured on horizontal surfaces. The variation of solar cell sensitivity to solar radiation is determined over a wide range of atmospheric condition. A new model was formulated that reduced the deviations between measured and predicted insolation to less than 3 percent. Evaluation of solar cell sensitivity data indicates small change (2-3 percent) in sensitivity from winter to summer for tilted cells. The feasibility of using such global data as a means for calibrating terrestrial solar cells is discussed.

  4. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam.

    PubMed

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-01-01

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 10(5) W/cm(2). The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime. PMID:26525516

  5. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam

    PubMed Central

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-01-01

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 105 W/cm2. The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime. PMID:26525516

  6. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam.

    PubMed

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-11-03

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 10(5) W/cm(2). The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime.

  7. Influence of Ice Particle Surface Roughening on the Global Cloud Radiative Effect

    NASA Technical Reports Server (NTRS)

    Yi, Bingqi; Yang, Ping; Baum, Bryan A.; LEcuyer, Tristan; Oreopoulos, Lazaros; Mlawer, Eli J.; Heymsfield, Andrew J.; Liou, Kuo-Nan

    2013-01-01

    Ice clouds influence the climate system by changing the radiation budget and large-scale circulation. Therefore, climate models need to have an accurate representation of ice clouds and their radiative effects. In this paper, new broadband parameterizations for ice cloud bulk scattering properties are developed for severely roughened ice particles. The parameterizations are based on a general habit mixture that includes nine habits (droxtals, hollow/solid columns, plates, solid/hollow bullet rosettes, aggregate of solid columns, and small/large aggregates of plates). The scattering properties for these individual habits incorporate recent advances in light-scattering computations. The influence of ice particle surface roughness on the ice cloud radiative effect is determined through simulations with the Fu-Liou and the GCM version of the Rapid Radiative Transfer Model (RRTMG) codes and the National Center for Atmospheric Research Community Atmosphere Model (CAM, version 5.1). The differences in shortwave (SW) and longwave (LW) radiative effect at both the top of the atmosphere and the surface are determined for smooth and severely roughened ice particles. While the influence of particle roughening on the single-scattering properties is negligible in the LW, the results indicate that ice crystal roughness can change the SW forcing locally by more than 10 W m(exp -2) over a range of effective diameters. The global-averaged SW cloud radiative effect due to ice particle surface roughness is estimated to be roughly 1-2 W m(exp -2). The CAM results indicate that ice particle roughening can result in a large regional SW radiative effect and a small but nonnegligible increase in the global LW cloud radiative effect.

  8. The effects of atomic oxygen on the thermal emittance of high temperature radiator surfaces

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Hotes, Deborah L.; Paulsen, Phillip E.

    1989-01-01

    Radiator surfaces on high temperature space power systems such as SP-100 space nuclear power system must maintain a high emittance level in order to reject waste heat effectively. One of the primary materials under consideration for the radiators is carbon-carbon composite. Since carbon is susceptible to attack by atomic oxygen in the low earth orbital environment, it is important to determine the durability of carbon composites in this environment as well as the effect atomic oxygen has on the thermal emittance of the surface if it is to be considered for use as a radiator. Results indicate that the thermal emittance of carbon-carbon composite (as low as 0.42) can be enhanced by exposure to a directed beam of atomic oxygen to levels above 0.85 at 800 K. This emittance enhancement is due to a change in the surface morphology as a result of oxidation. High aspect ratio cones are formed on the surface which allow more efficient trapping of incident radiation. Erosion of the surface due to oxidation is similar to that for carbon, so that at altitudes less than approximately 600 km, thickness loss of the radiator could be significant (as much as 0.1 cm/year). A protective coating or oxidation barrier forming additive may be needed to prevent atomic oxygen attack after the initial high emittance surface is formed. Textured surfaces can be formed in ground based facilities or possibly in space if emittance is not sensitive to the orientation of the atomic oxygen arrival that forms the texture.

  9. The effects of atomic oxygen on the thermal emittance of high temperature radiator surfaces

    SciTech Connect

    Rutledge, S.K.; Hotes, D.L.; Paulsen, P.E.

    1994-09-01

    Radiator surfaces on high temperature space power systems such as the SP-100 space nuclear power system must maintain a high emittance level in order to reject waste heat effectively. one of the primary materials under consideration for the radiators is carbon-carbon composite. Since carbon is susceptible to attack by atomic oxygen in the low Earth orbital environment, it is important to determine the durability of carbon composites in this environment as well as the effect atomic oxygen has on the thermal emittance of the surface if it is to be considered for use as a radiator. Results indicate that the thermal emittance of carbon-carbon composite (as low as 0.42) can be enhanced by exposure to a directed beam of atomic oxygen to levels above 0.85 at 800 K. This emittance enhancement is due to a change in the surface morphology as a result of oxidation. High aspect ratio cones are formed on the surface which allow more efficient trapping of incident radiation. Erosion of the surface due to oxidation is similar to that for carbon; so that at altitudes less than {approximately}600 km, thickness loss of the radiator could be significant (as much as 0.1 cm/year). A protective coating or oxidation barrier forming additive may be needed to prevent atomic oxygen attack after the initial high emittance surface is formed. Textured surfaces can be formed in ground based facilities or possibly in space if emittance is not sensitive to the orientation of the atomic oxygen arrival that forms the texture.

  10. A Climatology of Surface Cloud Radiative Effects at the ARM Tropical Western Pacific Sites

    SciTech Connect

    McFarlane, Sally A.; Long, Charles N.; Flaherty, Julia E.

    2013-04-01

    Cloud radiative effects on surface downwelling fluxes are investigated using long-term datasets from the three Atmospheric Radiation Measurement (ARM) sites in the Tropical Western Pacific (TWP) region. The Nauru and Darwin sites show significant variability in sky cover, downwelling radiative fluxes, and surface cloud radiative effect (CRE) due to El Niño and the Australian monsoon, respectively, while the Manus site shows little intra-seasonal or interannual variability. Cloud radar measurement of cloud base and top heights are used to define cloud types so that the effect of cloud type on the surface CRE can be examined. Clouds with low bases contribute 71-75% of the surface shortwave (SW) CRE and 66-74% of the surface longwave (LW) CRE at the three TWP sites, while clouds with mid-level bases contribute 8-9% of the SW CRE and 12-14% of the LW CRE, and clouds with high bases contribute 16-19% of the SW CRE and 15-21% of the LW CRE.

  11. Multi-decadal Change of Atmospheric Aerosols and their Effect on Surface Radiation

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diel, Thomas; Streets, David; Wild, Martin; Qian, Yun; Yu, Hongbin; Tan, Qian; Bian, Huisheng; Wang. Weiguo

    2012-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model GOCART along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007 during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. Particularly: (1) We compare the model calculated clear sky downward radiation at the surface with surface network data from Baseline Surface Radiation Network (BSRN) and CMA (2) We compare the model and surface data with satellite derived downward radiation products from ISCCP and SRB (3) We analyze the long-term global and regional aerosol trends in major anthropogenic source regions (North America, Europe, Asia) that have been experiencing considerable changes of emissions during the three decades, dust and biomass burning regions that have large interannual variability, downwind regions that are directly affected by the changes in the source area, and remote regions that are considered to representing "background" conditions.

  12. Interaction of surface plasmon polaritons in heavily doped GaN microstructures with terahertz radiation

    NASA Astrophysics Data System (ADS)

    Melentev, G. A.; Shalygin, V. A.; Vorobjev, L. E.; Panevin, V. Yu.; Firsov, D. A.; Riuttanen, L.; Suihkonen, S.; Korotyeyev, V. V.; Lyaschuk, Yu. M.; Kochelap, V. A.; Poroshin, V. N.

    2016-03-01

    We present the results of experimental and theoretical studies of the surface plasmon polariton excitations in heavily doped GaN epitaxial layers. Reflection and emission of radiation in the frequency range of 2-20 THz including the Reststrahlen band were investigated for samples with grating etched on the sample surface, as well as for samples with flat surface. The reflectivity spectrum for p-polarized radiation measured for the sample with the surface-relief grating demonstrates a set of resonances associated with excitations of different surface plasmon polariton modes. Spectral peculiarities due to the diffraction effect have been also revealed. The characteristic features of the reflectivity spectrum, namely, frequencies, amplitudes, and widths of the resonance dips, are well described theoretically by a modified technique of rigorous coupled-wave analysis of Maxwell equations. The emissivity spectra of the samples were measured under epilayer temperature modulation by pulsed electric field. The emissivity spectrum of the sample with surface-relief grating shows emission peaks in the frequency ranges corresponding to the decay of the surface plasmon polariton modes. Theoretical analysis based on the blackbody-like radiation theory well describes the main peculiarities of the observed THz emission.

  13. Satellite-based surface solar radiation data provided by CM SAF - Solar energy applications

    NASA Astrophysics Data System (ADS)

    Trentmann, Jörg; Müller, Richard W.; Posselt, Rebekka; Stöckli, Reto

    2013-04-01

    The planning of solar power plants requires accurate estimates of the solar energy available at the surface. Satellite observations provide useful information on the cloud coverage, which is one of the main factors modulating the solar surface radiation. This information can be used to estimate the solar surface radiation from satellite. Observations from geostationary satellites allow the retrieval of the surface solar radiation with high temporal (up to hourly) and spatial (approx. 5 km) resolution. The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) is deriving surface solar radiation from geostationary and polar-orbiting satellite instruments. While CM SAF is focusing on the generation of high-quality long-term climate data records, also operationally data is provided in short time latency within 8 weeks. CM SAF has already released one data set based on geostationary Meteosat satellite covering 1983 to 2005 (doi: 10.5676/EUM_SAF_CM/RAD_MVIRI/V001) and one global data set based on measurements of the polar-orbiting AVHRR instruments covering 1982 to 2009 (doi: 10.5676/EUM_SAF_CM/CLARA_AVHRR/V001). Here, we present details and applications of the CM SAF surface radiation data generated from the observations of the geostationary Meteosat satellites. The climate data set is available at high spatial (0.03 x 0.03 deg) and temporal (hourly, daily, monthly) resolutions. Besides global radiation, also the direct beam component is provided, which is for instance required for the estimation of the energy generated by solar thermal plants. Based on comparisons with surface observations the accuracy of CM SAF surface solar radiation data is better than 10 W/m2 on a monthly basis and 25 W/m2 on a daily basis. The data sets are well documented (incl. validation using surface observations) and available in netcdf-format at no cost without restrictions at www.cmsaf.eu. Solar energy applications of the data include the Photovoltaic Geographical

  14. [Effects of soil surface mulching on solar greenhouse grafted and own-rooted cucumber growth and soil environment].

    PubMed

    Zhai, Sheng; Liang, Yinli; Wang, Juyuan

    2005-12-01

    The study on the effects of different soil surface mulching models, including wheat straw mulching (WS), plastic film mulching (PF), and wheat straw plus plastic film mulching (WP), on the growth of solar greenhouse grafted and own-rooted cucumber and on soil environment showed that soil surface mulching not only increased the individuals of pistillate flower, improved its differentiation and development, shortened fruit-developing period, increased fruit weight, reduced fruit malformation percentage, but also raised total yield. Among the test mulching models, WP was better than WS and PF, and the effects were superior on grafted than on own-rooted cucumber. Soil surface mulching also had considerable effects on soil environment, but the effects varied with different modules. For example, under field condition, the diurnal change of soil temperature was a single-peak curve, with its peak higher and appeared at 14:30 in 5 cm and 10 cm soil depth, but lower and appeared later in deeper soil layers. In this study, WS lowered the maximum soil temperature and raised the minimum soil temperature, making soil temperature quite stable, while PF raised the maximum soil temperature much higher and enhanced the minimum soil temperature less than WS and WP, making the largest variation range of soil temperature. WP played a role of raising soil temperature and kept it stable. Similar to the diurnal change of soil temperature at 5 cm and 10 cm depth, that of soil respiration rate was also a single-peak curve. The soil respiration rate in all treatmentg was significantly higher than that of CK, and WP had a higher soil respiration rate than PF and WS. There was a significant positive correlation between soil respiration rate and soil temperature at 5 cm and 10 cm depth. By the end of the experiment, soil bulk density at the depth of 0-20 cm was measured, which was significantly lower in WS and WP than in CK and PF. The difference in soil bulk density was gradually inconspicuous

  15. 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.

  16. Measuring and modeling near-surface reflected and emitted radiation fluxes at the FIFE site

    NASA Technical Reports Server (NTRS)

    Blad, Blaine L.; Walter-Shea, Elizabeth A.; Starks, Patrick J.; Vining, Roel C.; Hays, Cynthia J.; Mesarch, Mark A.

    1990-01-01

    Information is presented pertaining to the measurement and estimation of reflected and emitted components of the radiation balance. Information is included about reflectance and transmittance of solar radiation from and through the leaves of some grass and forb prairie species, bidirectional reflectance from a prairie canopy is discussed and measured and estimated fluxes are described of incoming and outgoing longwave and shortwave radiation. Results of the study showed only very small differences in reflectances and transmittances for the adaxial and abaxial surfaces of grass species in the visible and infrared wavebands, but some differences in the infrared wavebands were noted for the forbs. Reflectance from the prairie canopy changed as a function of solar and view zenith angles in the solar principal plane with definite asymmetry about nadir. The surface temperature of prairie canopies was found to vary by as much as 5 C depending on view zenith and azimuth position and on the solar azimuth. Aerodynamic temperature calculated from measured sensible heat fluxes ranged from 0 to 3 C higher than nadir-viewed temperatures. Models were developed to estimate incoming and reflected shortwave radiation from data collected with a Barnes Modular Multiband Radiometer. Several algorithms for estimating incoming longwave radiation were evaluated and compared to actual measures of that parameter. Net radiation was calculated using the estimated components of the shortwave radiation streams, determined from the algorithms developed, and from the longwave radiation streams provided by the Brunt, modified Deacon, and the Stefan-Boltzmann models. Estimates of net radiation were compared to measured values and found to be within the measurement error of the net radiometers used in the study.

  17. The WCRP/GEWEX Surface Radiation Budget Project Release 2: An Assessment of Surface Fluxes at 1 Degree Resolution

    NASA Technical Reports Server (NTRS)

    Stackhouse, P. W., Jr.; Gupta, S. K.; Cox, S. J.; Chiacchio, M.; Mikovitz, J. C.

    2004-01-01

    The U.S. National Aeronautics and Space Administration (NASA) based Surface Radiation Budget (SRB) Project in association with the World Climate Research Programme Global Energy and Water Cycle Experiment (WCRP/GEWEX) is preparing a new 1 deg x 1 deg horizontal resolution product for distribution scheduled for release in early 2001. The new release contains several significant upgrades from the previous version. This paper summarizes the most significant upgrades and presents validation results as an assessment of the new data set.

  18. A transcriptional regulator of the LuxR-UhpA family, FlcA, controls flocculation and wheat root surface colonization by Azospirillum brasilense Sp7.

    PubMed

    Pereg-Gerk, L; Paquelin, A; Gounon, P; Kennedy, I R; Elmerich, C

    1998-03-01

    Genetic complementation of a spontaneous mutant, impaired in flocculation, Congo red binding, and colonization of root surface, led to the identification of a new regulatory gene in Azospirillum brasilense Sp7, designated flcA. The deduced amino acid sequence of flcA shared high similarity with a family of transcriptional activators of the LuxR-UphA family. The most significant match was with the AgmR protein, an activator for glycerol metabolism in Pseudomonas aeruginosa. Derivatives of Sp7 resulting from site-directed Tn5 mutagenesis in the flcA coding sequence were constructed by marker exchange. Characterization of the resulting mutant strains showed that flcA controls the production of capsular polysaccharides, the flocculation process in culture, and the colonization of the root surface of wheat. This study provides new information on the genetic control of the mechanism of plant root colonization by Azospirillum.

  19. Method for surface plasmon amplification by stimulated emission of radiation (SPASER)

    DOEpatents

    Stockman, Mark I.; Bergman, David J.

    2011-09-13

    A nanostructure is used to generate a highly localized nanoscale optical field. The field is excited using surface plasmon amplification by stimulated emission of radiation (SPASER). The SPASER radiation consists of surface plasmons that undergo stimulated emission, but in contrast to photons can be localized within a nanoscale region. A SPASER can incorporate an active medium formed by two-level emitters, excited by an energy source, such as an optical, electrical, or chemical energy source. The active medium may be quantum dots, which transfer excitation energy by radiationless transitions to a resonant nanosystem that can play the same role as a laser cavity in a conventional laser. The transitions are stimulated by the surface plasmons in the nanostructure, causing the buildup of a macroscopic number of surface plasmons in a single mode.

  20. Effect of Joule heating and thermal radiation in flow of third grade fluid over radiative surface.

    PubMed

    Hayat, Tasawar; Shafiq, Anum; Alsaedi, Ahmed

    2014-01-01

    This article addresses the boundary layer flow and heat transfer in third grade fluid over an unsteady permeable stretching sheet. The transverse magnetic and electric fields in the momentum equations are considered. Thermal boundary layer equation includes both viscous and Ohmic dissipations. The related nonlinear partial differential system is reduced first into ordinary differential system and then solved for the series solutions. The dependence of velocity and temperature profiles on the various parameters are shown and discussed by sketching graphs. Expressions of skin friction coefficient and local Nusselt number are calculated and analyzed. Numerical values of skin friction coefficient and Nusselt number are tabulated and examined. It is observed that both velocity and temperature increases in presence of electric field. Further the temperature is increased due to the radiation parameter. Thermal boundary layer thickness increases by increasing Eckert number. PMID:24454694

  1. Solar irradiance computations compared with observations at the Baseline Surface Radiation Network Payerne site

    SciTech Connect

    Nowak, Daniela; Vuilleumier, Laurent; Long, Charles N.; Ohmura, Atsumu

    2008-07-18

    Radiative transfer model calculations of solar fluxes during cloud free periods often show considerable discrepancies with surface radiation observations. Many efforts have been undertaken to explain the differences between modeled and observed shortwave downward radiation (SDR). In this study, MODTRAN4v3r1TM (designed later simply as MODTRANTM) was used for model simulations and compared with high quality radiation observations of the Baseline Surface Radiation Network (BSRN) site at Payerne, Switzerland. Results are presented for cloud free shortwave downward radiation calculations. The median differences of modeled minus observed global SDR are small (< 1%) and within the instrumental error. The differences of modeled and observed direct and diffuse SDR show larger discrepancies of -1.8% and 5.2% respectively. The diffuse SDR is generally overestimated by the model and more important, the model to observation linear regression slope and zero-intercept differs significantly from their ideal values of 1 and 0. Possible reasons for the discrepancies are presented and discussed and some modifications are investigated for decreasing such differences between modeled and observed diffuse SDR. However, we could not resolve all the discrepancies. The best agreement is obtained when comparing model simulations whose 550nm aerosol optical depth input is inferred from observations using nine spectral channels, and using BSRN observations performed with a new and more precise shading disk and sun tracker system. In this case, the median bias between model simulations and observed diffuse SDR is -0.4 Wm-2 (< 1%).

  2. Progress in Projecting Solar Radiation at the Earth's Surface in Climate Models

    NASA Astrophysics Data System (ADS)

    Collins, W.; Fildier, B.; Feldman, D.

    2015-12-01

    Projecting changes in solar radiation at the Earth's surface in futureclimates is a critical input to forecast surface irradiance for solarenergy. We demonstrate the current state of the art using theensemble of opportunity assembled for the Coupled ModelIntercomparison Project (CMIP5) and the Fifth Assessment Report (AR5)of the Intergovernmental Panel on Climate Change (IPCC). The reliability of these projections depends upon the accuracy of theunderlying radiation codes, the fidelity of these codes to themeasured optical properties of key radiatively active atmosphericconstituents, and the realism of future projections of theseatmospheric constituents. These constituents include aerosols,clouds, water vapor, greenhouse gases that absorb near-infraredsunlight. Since the realism of future projections of anthropogenicaerosol species is contingent on the underlying scenario, we focus onthe other challenges in forecasting surface irradiance. Regarding accuracy, we demonstrate that current GCM shortwaveparameterizations often exhibit quite small errors relative tobenchmark radiative transfer codes. In addition, recent work hasbracketed the uncertainties in solar irradiance associated withcomplex cloud geometries. There is also an emerging consensus howcloud radiative effects will evolve in a warmer climate. However,there is evidence that current GCM codes still exhibit systematicerrors in the near-infrared water vapor bands, particularly for moistsub-tropical atmospheres. These errors will become more acute aswater vapor feedbacks, combined with global warming, increase thetotal precipitable water in the Earth's atmosphere.

  3. Distinct impact of different types of aerosols on surface solar radiation in China

    NASA Astrophysics Data System (ADS)

    Yang, Xin; Zhao, Chuanfeng; Zhou, Lijing; Wang, Yang; Liu, Xiaohong

    2016-06-01

    Observations of surface direct solar radiation (DSR) and visibility, particulate matter with aerodynamic diameters less than 2.5 µm (PM2.5), together with the aerosol optical thickness (AOT) taken from Moderate-Resolution Imaging Spectroradiometer and Multiangle Imaging Spectroradiometer, were investigated to gain insight into the impact of aerosol pollution on surface solar radiation in China. The surface DSR decreased during 2004-2014 compared with 1993~2003 over eastern China, but no clear reduction was observed in remote regions with cleaner air. Significant correlations of visibility, PM2.5, and regionally averaged AOT with the surface DSR over eastern China indicate that aerosol pollution greatly affects the energy available at the surface. The net loss of surface solar radiation also reduces the surface ground temperature over eastern China. However, the slope of the linear variation of the radiation with respect to atmospheric visibility is distinctly different at different stations, implying that the main aerosol type varies regionally. The largest slope value occurs at Zhengzhou and indicates that the aerosol absorption in central China is the highest, and lower slope values suggest relatively weakly absorbing types of aerosols at other locations. The spatial distribution of the linear slopes agrees well with the geographical distribution of the absorbing aerosols derived from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations and Ozone Monitoring Instrument over China. The regional correlation between a larger slope value and higher absorbance properties of aerosols indicates that the net effects of aerosols on the surface solar energy and corresponding climatic effects are dependent on both aerosol amount and optical properties.

  4. The Martian surface radiation environment - a comparison of models and MSL/RAD measurements

    NASA Astrophysics Data System (ADS)

    Matthiä, Daniel; Ehresmann, Bent; Lohf, Henning; Köhler, Jan; Zeitlin, Cary; Appel, Jan; Sato, Tatsuhiko; Slaba, Tony; Martin, Cesar; Berger, Thomas; Boehm, Eckart; Boettcher, Stephan; Brinza, David E.; Burmeister, Soenke; Guo, Jingnan; Hassler, Donald M.; Posner, Arik; Rafkin, Scot C. R.; Reitz, Günther; Wilson, John W.; Wimmer-Schweingruber, Robert F.

    2016-03-01

    Context: The Radiation Assessment Detector (RAD) on the Mars Science Laboratory (MSL) has been measuring the radiation environment on the surface of Mars since August 6th 2012. MSL-RAD is the first instrument to provide detailed information about charged and neutral particle spectra and dose rates on the Martian surface, and one of the primary objectives of the RAD investigation is to help improve and validate current radiation transport models. Aims: Applying different numerical transport models with boundary conditions derived from the MSL-RAD environment the goal of this work was to both provide predictions for the particle spectra and the radiation exposure on the Martian surface complementing the RAD sensitive range and, at the same time, validate the results with the experimental data, where applicable. Such validated models can be used to predict dose rates for future manned missions as well as for performing shield optimization studies. Methods: Several particle transport models (GEANT4, PHITS, HZETRN/OLTARIS) were used to predict the particle flux and the corresponding radiation environment caused by galactic cosmic radiation on Mars. From the calculated particle spectra the dose rates on the surface are estimated. Results: Calculations of particle spectra and dose rates induced by galactic cosmic radiation on the Martian surface are presented. Although good agreement is found in many cases for the different transport codes, GEANT4, PHITS, and HZETRN/OLTARIS, some models still show large, sometimes order of magnitude discrepancies in certain particle spectra. We have found that RAD data is helping to make better choices of input parameters and physical models. Elements of these validated models can be applied to more detailed studies on how the radiation environment is influenced by solar modulation, Martian atmosphere and soil, and changes due to the Martian seasonal pressure cycle. By extending the range of the calculated particle spectra with respect to

  5. In vitro studies of the ablation mechanism of periodontopathic bacteria and decontamination effect on periodontally diseased root surfaces by erbium:yttrium-aluminum-garnet laser.

    PubMed

    Akiyama, Fumihiko; Aoki, Akira; Miura-Uchiyama, Mako; Sasaki, Katia M; Ichinose, Shizuko; Umeda, Makoto; Ishikawa, Isao; Izumi, Yuichi

    2011-03-01

    The erbium:yttrium-aluminum-garnet (Er:YAG) laser is now increasingly used in periodontal therapy. The purpose of this study was to investigate the effect of Er:YAG laser irradiation on the morphology of periodontopathic bacteria and to compare the bacterial elimination effect of the laser and the ultrasonic scaler on diseased root surfaces in vitro. Colonies of Porphyromonas gingivalis were exposed to a single-pulse Er:YAG laser at 40 mJ and were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Also, 20 pairs of periodontally diseased root surfaces with subgingival calculi of freshly extracted teeth were treated by Er:YAG laser scaling at 40 mJ/pulse (14.2 J/cm(2) per pulse) and 10 Hz with water spray or ultrasonic scaling, or were not treated. The efficiency of each treatment was determined as the area treated per second, and the treated surfaces were examined by SEM. The material scraped from the treated root surfaces was cultured in aerobic and anaerobic conditions, and the numbers of colony forming units (CFUs) were compared. SEM and TEM showed that the Er:YAG laser had easily ablated the bacterial colony, leaving an ablation spot with a crater and the surrounding affected area showing melted branch-like structures. The laser irradiation was as equally effective and efficient as the ultrasonic scaler in performing root surface debridement. The CFUs after laser treatment were significantly fewer than those after ultrasonic scaling in aerobic and anaerobic culture conditions. Er:YAG laser ablates periodontopathic bacteria with thermal vaporization, and its bacterial elimination effect on the diseased root surfaces appears to be superior to that of the ultrasonic scaler.

  6. Surface Emissivity Maps for Use in Satellite Retrievals of Longwave Radiation

    NASA Technical Reports Server (NTRS)

    Wilber, Anne C.; Kratz, David P.; Gupta, Shashi K.

    1999-01-01

    Accurate accounting of surface emissivity is essential for the retrievals of surface temperature from remote sensing measurements, and for the computations of longwave (LW) radiation budget of the Earth?s surface. Past studies of the above topics assumed that emissivity for all surface types, and across the entire LW spectrum is equal to unity. There is strong evidence, however, that emissivity of many surface materials is significantly lower than unity, and varies considerably across the LW spectrum. We have developed global maps of surface emissivity for the broadband LW region, the thermal infrared window region (8-12 micron), and 12 narrow LW spectral bands. The 17 surface types defined by the International Geosphere Biosphere Programme (IGBP) were adopted as such, and an additional (18th) surface type was introduced to represent tundra-like surfaces. Laboratory measurements of spectral reflectances of 10 different surface materials were converted to corresponding emissivities. The 10 surface materials were then associated with 18 surface types. Emissivities for the 18 surface types were first computed for each of the 12 narrow spectral bands. Emissivities for the broadband and the window region were then constituted from the spectral band values by weighting them with Planck function energy distribution.

  7. 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.

  8. An Improved Algorithm for Retrieving Surface Downwelling Longwave Radiation from Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Zhou, Yaping; Kratz, David P.; Wilber, Anne C.; Gupta, Shashi K.; Cess, Robert D.

    2007-01-01

    Zhou and Cess [2001] developed an algorithm for retrieving surface downwelling longwave radiation (SDLW) based upon detailed studies using radiative transfer model calculations and surface radiometric measurements. Their algorithm linked clear sky SDLW with surface upwelling longwave flux and column precipitable water vapor. For cloudy sky cases, they used cloud liquid water path as an additional parameter to account for the effects of clouds. Despite the simplicity of their algorithm, it performed very well for most geographical regions except for those regions where the atmospheric conditions near the surface tend to be extremely cold and dry. Systematic errors were also found for scenes that were covered with ice clouds. An improved version of the algorithm prevents the large errors in the SDLW at low water vapor amounts by taking into account that under such conditions the SDLW and water vapor amount are nearly linear in their relationship. The new algorithm also utilizes cloud fraction and cloud liquid and ice water paths available from the Cloud and the Earth's Radiant Energy System (CERES) single scanner footprint (SSF) product to separately compute the clear and cloudy portions of the fluxes. The new algorithm has been validated against surface measurements at 29 stations around the globe for Terra and Aqua satellites. The results show significant improvement over the original version. The revised Zhou-Cess algorithm is also slightly better or comparable to more sophisticated algorithms currently implemented in the CERES processing and will be incorporated as one of the CERES empirical surface radiation algorithms.

  9. Efficient conversion of surface-plasmon-like modes to spatial radiated modes

    SciTech Connect

    Xu, Jun Jun; Zhang, Hao Chi; Zhang, Qian; Cui, Tie Jun

    2015-01-12

    We propose a spoof surface plasmon polariton (SPP) emitter which is composed of ultrathin corrugated metallic strips, exhibiting the directional radiation property. The spoof SPP emitter provides a way to quickly convert the SPP mode to a radiated mode. By controlling phase modulations produced by the phase-gradient metasurface on the ultrathin metallic strips, we demonstrate theoretically and experimentally that spoof SPP waves are converted into spatial propagating waves with high efficiency, which are further radiated with flexible beam steering. The proposed method sets up a link between SPP waves and radiation waves in a highly controllable way, which would possibly open an avenue in designing new kinds of microwave and optical elements in engineering.

  10. A theory for the radiation of magnetohydrodynamic surface waves and body waves into the solar corona

    NASA Technical Reports Server (NTRS)

    Davila, Joseph M.

    1988-01-01

    The Green's function for the slab coronal hole is obtained explicitly. The Fourier integral representation for the radiated field inside and outside the coronal hole waveguide is obtained. The radiated field outside the coronal hole is calculated using the method of steepest descents. It is shown that the radiated field can be written as the sum of two contributions: (1) a contribution from the integral along the steepest descent path and (2) a contribution from all the poles of the integrand between the path of the original integral and the steepest descent path. The free oscillations of the waveguide can be associated with the pole contributions in the steepest descent representation for the Green's function. These pole contributions are essentially generalized surface waves with a maximum amplitude near the interface which separates the plasma inside the coronal hole from the surrounding background corona. The path contribution to the integral is essentially the power radiated in body waves.

  11. Soil Moisture Active Passive (SMAP) Mission Level 4 Surface and Root Zone Soil Moisture (L4_SM) Product Specification Document

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; Ardizzone, Joseph V.; Kim, Gi-Kong; Lucchesi, Robert A.; Smith, Edmond B.; Weiss, Barry H.

    2015-01-01

    This is the Product Specification Document (PSD) for Level 4 Surface and Root Zone Soil Moisture (L4_SM) data for the Science Data System (SDS) of the Soil Moisture Active Passive (SMAP) project. The L4_SM data product provides estimates of land surface conditions based on the assimilation of SMAP observations into a customized version of the NASA Goddard Earth Observing System, Version 5 (GEOS-5) land data assimilation system (LDAS). This document applies to any standard L4_SM data product generated by the SMAP Project. The Soil Moisture Active Passive (SMAP) mission will enhance the accuracy and the resolution of space-based measurements of terrestrial soil moisture and freeze-thaw state. SMAP data products will have a noteworthy impact on multiple relevant and current Earth Science endeavors. These include: Understanding of the processes that link the terrestrial water, the energy and the carbon cycles, Estimations of global water and energy fluxes over the land surfaces, Quantification of the net carbon flux in boreal landscapes Forecast skill of both weather and climate, Predictions and monitoring of natural disasters including floods, landslides and droughts, and Predictions of agricultural productivity. To provide these data, the SMAP mission will deploy a satellite observatory in a near polar, sun synchronous orbit. The observatory will house an L-band radiometer that operates at 1.40 GHz and an L-band radar that operates at 1.26 GHz. The instruments will share a rotating reflector antenna with a 6 meter aperture that scans over a 1000 km swath.

  12. Tuning near field radiative heat flux through surface excitations with a metal insulator transition.

    PubMed

    van Zwol, P J; Ranno, L; Chevrier, J

    2012-06-01

    The control of heat flow is a formidable challenge due to lack of good thermal insulators. Promising new opportunities for heat flow control were recently theoretically discovered for radiative heat flow in near field, where large heat flow contrasts may be achieved by tuning electronic excitations on surfaces. Here we show experimentally that the phase transition of VO2 entails a change of surface polariton states that significantly affects radiative heat transfer in near field. In all cases the Derjaguin approximation correctly predicted radiative heat transfer in near field, but it underestimated the far field limit. Our results indicate that heat flow contrasts can be realized in near field that can be larger than those obtained in far field. PMID:23003960

  13. The `Chocolate Experiment' - A Demonstration of Radiation Absorption by Different Colored Surfaces

    NASA Astrophysics Data System (ADS)

    Fung, Dennis

    2015-12-01

    In the typical "cookbook" experiment comparing the radiation absorption rates of different colored surfaces, students' hands are commonly used as a measurement instrument to demonstrate that dull black and silvery surfaces are good and poor absorbers of radiation, respectively. However, college students are often skeptical about using their bare hands in this experiment because they learned in early science lessons that skin is not a reliable detector of heat transfer. Moreover, when the experiment is conducted in a school laboratory, it is often difficult for students to perceive the slight differences in heat transfer on the dull black and silvery aluminum leaves attached to their hands. Rather than replacing students' bare hands with such sophisticated apparatus as a data logger and temperature probe, I suggest using a simple (and delicious!) low-cost instrument, i.e., chocolate, which simply melts when it receives radiation.

  14. The Nature of Clouds and Their Effects on the Surface Radiative Energy Budget

    NASA Astrophysics Data System (ADS)

    Long, C.; Ackerman, T. P.; Gaustad, K.; Barnard, J.; Turner, D.

    2005-12-01

    Recently significant progress has been made in inferring cloud effects and cloud macrophysical properties using surface measurements of broadband irradiance and basic meteorological variables. These "Flux Analysis" methodologies build on the original work by Long and Ackerman (2000), who show that these techniques include a high degree of repeatability since both the clear-sky and all-sky values include the same measuring instrument characteristics. Examples of the Flux Analysis methodology applied to measurements from various ARM and BSRN sites spanning the years of available data will be presented. These results include analyses of shortwave (SW) and longwave (LW) all-sky and clear-sky climatology; SW, LW, and net cloud effects; total (daylight) and LW effective (24 hour) fractional sky cover; cloud transmissivity and visible optical thickness; and estimates of cloud field effective radiating temperature and radiating surface height. Preliminary results of the upwelling components of clear-sky and cloud effect will also be presented, and used to infer the total net surface radiative cloud forcing. Through these examples, the nature of cloudiness and the resultant influence on the surface radiative energy budget will be described.

  15. Impacts of Climate Change and Land use Changes on Land Surface Radiation and Energy Budgets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface radiation and energy budgets are critical to address a variety of scientific and application issues related to climate trends, weather predictions, hydrologic and biogeophysical modeling, and the monitoring of ecosystem health and agricultural crops. This is an introductory paper to t...

  16. Radiation climate map for analyzing risks to astronauts on the mars surface from galactic cosmic rays

    NASA Astrophysics Data System (ADS)

    Saganti, Premkumar B.; Cucinotta, Francis A.; Wilson, John W.; Simonsen, Lisa C.; Zeitlin, Cary

    2004-01-01

    The potential risks for late effects including cancer, cataracts, and neurological disorders due to exposures to the galactic cosmic rays (GCR) is a large concern for the human exploration of Mars. Physical models are needed to project the radiation exposures to be received by astronauts in transit to Mars and on the Mars surface, including the understanding of the modification of the GCR by the Martian atmosphere and identifying shielding optimization approaches. The Mars Global Surveyor (MGS) mission has been collecting Martian surface topographical data with the Mars Orbiter Laser Altimeter (MOLA). Here we present calculations of radiation climate maps of the surface of Mars using the MOLA data, the radiation transport model HZETRN (high charge and high energy transport), and the quantum multiple scattering fragmentation model, QMSFRG. Organ doses and the average number of particle hits per cell nucleus from GCR components (protons, heavy ions, and neutrons) are evaluated as a function of the altitude on the Martian surface. Approaches to improve the accuracy of the radiation climate map, presented here using data from the 2001 Mars Odyssey mission, are discussed.

  17. Radiation Climate Map for Analyzing Risks to Astronauts on the Mars Surface from Galactic Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Saganti, Premkumar B.; Cucinotta, Francis A.; Wilson, John W.; Simonsen, Lisa C.; Zeitlin, Cary

    The potential risks for late effects including cancer, cataracts, and neurological disorders due to exposures to the galactic cosmic rays (GCR) is a large concern for the human exploration of Mars. Physical models are needed to project the radiation exposures to be received by astronauts in transit to Mars and on the Mars surface, including the understanding of the modification of the GCR by the Martian atmosphere and identifying shielding optimization approaches. The Mars Global Surveyor (MGS) mission has been collecting Martian surface topographical data with the Mars Orbiter Laser Altimeter (MOLA). Here we present calculations of radiation climate maps of the surface of Mars using the MOLA data, the radiation transport model HZETRN (high charge and high energy transport), and the quantum multiple scattering fragmentation model, QMSFRG. Organ doses and the average number of particle hits per cell nucleus from GCR components (protons, heavy ions, and neutrons) are evaluated as a function of the altitude on the Martian surface. Approaches to improve the accuracy of the radiation climate map, presented here using data from the 2001 Mars Odyssey mission, are discussed.

  18. Observation of radiative surface plasmons in metal-oxide-metal tunnel junctions

    NASA Technical Reports Server (NTRS)

    Donohue, J. F.; Yang, E. Y.

    1986-01-01

    A peak in the UV region of the spectrum of light emitted from metal-oxide-metal (MOM) tunnel junctions has been observed at room temperature. Both the amplitude and wavelength of the peak are sensitive to applied junction bias. The UV peak corresponds to the normal or radiative surface plasmon mode while a visible peak, also present in the present spectra and reported in past MOM literature, is due to the tangential or nonradiative mode. The radiative mode requires no surface roughness or gratings for photon coupling. The results show that it is possible to obtain radiative surface plasmon production followed by a direct decay into photons with MOM tunnel diodes. A MOM diode with a double anode structure is found to emit light associated only with the nonradiative mode. The thickness dependence of the UV peak, along with the experimental results of the double anode MOM diode and the ratio of the UV peak to visible peak, support the contention that the UV light emission is indeed due to the radiative surface plasmon.

  19. Surface energy and radiation budgets in a steppe ecosystem in the Upper Columbia River Gorge

    SciTech Connect

    Whiteman, C.D.; Allwine, K.J.; Bian, X.

    1994-08-01

    Measurements of radiation and surface energy budget components are presented for a semiarid grassland-steppe ecosystem in the Upper Columbia River Gorge (45{degrees}45`25.6 inches N, 120{degrees}01`39.3 inches W, 190 m) for June 2-27, 1991. Over this period, the ratio of sensible to latent heat flux (the Bowen ratio) averaged 5.0, and mean daily surface energy balance totals were: net radiation, 9.23; ground heat flux, 1.25; latent heat flux, 1.32; and sensible heat flux, 6.66 MJ m{sup {minus}2} d{sup {minus}1}, where the mean daily nonradiative fluxes were directed away from the surface, and the mean daily radiative flux was directed toward the surface. On clear days, the site received from 0.71 to 0.76 of the theoretical extraterrestrial solar radiation. Albedo over the 26-d period varied from 0.17 to 0.21. Daily and daytime average values of the components are summarized, and a plot is presented of the 30-min average values of all components for the entire period.

  20. Observational determination of surface radiative forcing by CO2 from 2000 to 2010.

    PubMed

    Feldman, D R; Collins, W D; Gero, P J; Torn, M S; Mlawer, E J; Shippert, T R

    2015-03-19

    The climatic impact of CO2 and other greenhouse gases is usually quantified in terms of radiative forcing, calculated as the difference between estimates of the Earth's radiation field from pre-industrial and present-day concentrations of these gases. Radiative transfer models calculate that the increase in CO2 since 1750 corresponds to a global annual-mean radiative forcing at the tropopause of 1.82 ± 0.19 W m(-2) (ref. 2). However, despite widespread scientific discussion and modelling of the climate impacts of well-mixed greenhouse gases, there is little direct observational evidence of the radiative impact of increasing atmospheric CO2. Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations-the Southern Great Plains and the North Slope of Alaska-are derived from Atmospheric Emitted Radiance Interferometer spectra together with ancillary measurements and thoroughly corroborated radiative transfer calculations. The time series both show statistically significant trends of 0.2 W m(-2) per decade (with respective uncertainties of ±0.06 W m(-2) per decade and ±0.07 W m(-2) per decade) and have seasonal ranges of 0.1-0.2 W m(-2). This is approximately ten per cent of the trend in downwelling longwave radiation. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance.

  1. Observational determination of surface radiative forcing by CO2 from 2000 to 2010.

    PubMed

    Feldman, D R; Collins, W D; Gero, P J; Torn, M S; Mlawer, E J; Shippert, T R

    2015-03-19

    The climatic impact of CO2 and other greenhouse gases is usually quantified in terms of radiative forcing, calculated as the difference between estimates of the Earth's radiation field from pre-industrial and present-day concentrations of these gases. Radiative transfer models calculate that the increase in CO2 since 1750 corresponds to a global annual-mean radiative forcing at the tropopause of 1.82 ± 0.19 W m(-2) (ref. 2). However, despite widespread scientific discussion and modelling of the climate impacts of well-mixed greenhouse gases, there is little direct observational evidence of the radiative impact of increasing atmospheric CO2. Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations-the Southern Great Plains and the North Slope of Alaska-are derived from Atmospheric Emitted Radiance Interferometer spectra together with ancillary measurements and thoroughly corroborated radiative transfer calculations. The time series both show statistically significant trends of 0.2 W m(-2) per decade (with respective uncertainties of ±0.06 W m(-2) per decade and ±0.07 W m(-2) per decade) and have seasonal ranges of 0.1-0.2 W m(-2). This is approximately ten per cent of the trend in downwelling longwave radiation. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance. PMID:25731165

  2. Observational determination of surface radiative forcing by CO2 from 2000 to 2010

    SciTech Connect

    Feldman, Daniel R.; Collins, William D.; Gero, P. Johnathan; Torn, Margaret S.; Mlawer, Eli J.; Shippert, Timothy R.

    2015-02-25

    The climatic impact of CO2 and other greenhouse gases is usually quantified in terms of radiative forcing1, calculated as the difference between estimates of the Earth’s radiation field from pre-industrial and present-day concentrations of these gases. Radiative transfer models calculate that the increase in CO2 since 1750 corresponds to a global annual-mean radiative forcing at the tropopause of 1.82 ± 0.19 W m-2 (ref. 2). However, despite widespread scientific discussion and modelling of the climate impacts of well-mixed greenhouse gases, there is little direct observational evidence of the radiative impact of increasing atmospheric CO2. Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations—the Southern Great Plains and the North Slope of Alaska—are derived from Atmospheric Emitted Radiance Interferometer spectra3 together with ancillary measurements and thoroughly corroborated radiative transfer calculations4. The time series both show statistically significant trends of 0.2 W m-2 per decade (with respective uncertainties of ±0.06 W m-2 per decade and ±0.07 W m-2 per decade) and have seasonal ranges of 0.1–0.2 W m-2. This is approximately ten per cent of the trend in downwelling longwave radiation5, 6, 7. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance.

  3. Reflight of the Solid Surface Combustion Experiment: Flame Radiation Near Extinction

    NASA Technical Reports Server (NTRS)

    Altenkirch, R. A.; Bundy, M. F.; Tang, L.; Bhattacharjee, S.; Sacksteder, K.; Delichatsios, M. A.

    1999-01-01

    In flame spreading in quiescent and low-velocity opposing flows, effects of surface reradiation and flame radiation are important in establishing the spread rate and whether the flame, once ignited, survives to steady spread or extinguishes after a time long compared to the ignition event. A reflight of the Solid Surface Combustion Experiment (SSCE), supported by modelling, demonstrates that for thick, flat fuels, the ultimate fate of the flame is extinction rather than steady spread. A mismatch between the thermal scale in the gas, driven by radiation, and the species diffusion scale, driven by mass diffusion, develops such that the high temperature regions of the flame are ultimately located in a region to which oxygen cannot be supplied at a sufficient rate to sustain reaction, and extinction occurs. Results of the experiment conducted on Space Shuttle mission STS 85 on 9 August 1997 are reviewed. For the flat surface geometry, while the hydrodynamic phenomena associated with opposed-flow flame spread may be treated two dimensionally, the radiative effects are three dimensional, and so modelling the radiative processes, with the mismatch in dimensionality, is difficult. The cylindrical geometry at least one long compared to the radius, provides a configuration in which the radiative processes for spread in the axial direction are two dimensional, thus simplifying the modelling. The cylindrical geometry allows for the development of more sophisticated radiative models without the complication of dimensionality concerns, e.g., discrete transfer, which is discussed in detail by Bundy (1998). Additionally, the cylindrical geometry results in a "focussing" of the heat transfer to the surface and may allow for steady spread for radii that for thick fuels of the same half-thickness there is no steady spread.

  4. Mercury net methylation in five tropical flood plain regions of Brazil: high in the root zone of floating macrophyte mats but low in surface sediments and flooded soils.

    PubMed

    Guimarães, J R; Meili, M; Hylander, L D; de Castro e Silva, E; Roulet, M; Mauro, J B; de Lemos, R

    2000-10-16

    In aquatic systems, bottom sediments have often been considered as the main methylmercury (MeHg) production site. In tropical floodplain areas, however, floating meadows and flooded forests extend over large areas and can be important Hg methylating sites. We present here a cross-system comparison of the Hg net methylation capacity in surface sediments, flooded soils and roots of floating aquatic macrophytes, assayed by in situ incubation with 203Hg and extraction of formed Me203 Hg by acid leaching and toluene. The presence of mono-MeHg was confirmed by thin layer chromatography and other techniques. Study areas included floodplain lakes in the Amazon basin (Tapajós, Negro and Amazon rivers), the Pantanal floodplain (Paraguay river basin), freshwater coastal lagoons in Rio de Janeiro and oxbow lakes in the Mogi-Guaçú river, São Paulo state. Different Hg levels were added in assays performed in 1994-1998, but great care was taken to standardise all other test parameters, to allow data comparisons. Net MeHg production was one order of magnitude higher (mean 13.8%, range 0.28-35) in the living or decomposing roots of floating or rooted macrophyte mats (Eichhornia azurea, E. crassipes, Paspalum sp., Eleocharis sellowiana, Salvinia sp., S. rotundifolia and Scirpus cubensis) than in the surface layer of underlying lake sediments (mean 0.6%, range 0.022-2.5). Methylation in flooded soils presented a wide range and was in some cases similar to the one found in macrophyte roots but usually much lower. In a Tapajós floodplain lake, natural concentrations of MeHg in soil and sediment cores taken along a lake-forest transect agreed well with data on net methylation potentials in the same samples. E. azurea, E. crassipes and Salvinia presented the highest methylation potentials, up to 113 times higher than in sediments. Methylation in E. azurea from six lakes of the Paraguay and Cuiabá rivers, high Pantanal, was determined in the 1998 dry and wet seasons and ranged from

  5. The forward scattering of microwave solar radiation from a water surface

    NASA Technical Reports Server (NTRS)

    Wentz, F. J.

    1978-01-01

    The forward scattering of microwave solar radiation from both smooth and rough water surfaces is computed. The smooth surface is assumed specular, and the rough surface is represented by a two-scale surface, for which two small-scale perturbation parameters, 0.10 and 0.25, are considered. The contribution of the scattered sunlight to the antenna temperature is found using the scalar approximation, and the results are compared with radiometer measurements. The overall agreement is good, but in some cases the smooth-surface measurements are higher than the computations. This discrepancy possibly indicates an absolute calibration error or a slight misalignment of the antennas' boresights. The computations for the two perturbation parameters bracket the rough-surface measurements except when the sun's mirror image is far removed from the boresight direction. The small disagreement in this case may be due to a peaked large-scale slope distribution.

  6. Reducing Strength Prevailing at Root Surface of Plants Promotes Reduction of Ag+ and Generation of Ag0/Ag2O Nanoparticles Exogenously in Aqueous Phase

    PubMed Central

    Pardha-Saradhi, Peddisetty; Yamal, Gupta; Peddisetty, Tanuj; Sharmila, Peddisetty; Nagar, Shilpi; Singh, Jyoti; Nagarajan, Rajamani; Rao, Kottapalli S.

    2014-01-01

    Potential of root system of plants from wide range of families to effectively reduce membrane impermeable ferricyanide to ferrocyanide and blue coloured 2,6-dichlorophenol indophenol (DCPIP) to colourless DCPIPH2 both under non-sterile and sterile conditions, revealed prevalence of immense reducing strength at root surface. As generation of silver nanoparticles (NPs) from Ag+ involves reduction, present investigations were carried to evaluate if reducing strength prevailing at surface of root system can be exploited for reduction of Ag+ and exogenous generation of silver-NPs. Root system of intact plants of 16 species from 11 diverse families of angiosperms turned clear colorless AgNO3 solutions, turbid brown. Absorption spectra of these turbid brown solutions showed silver-NPs specific surface plasmon resonance peak. Transmission electron microscope coupled with energy dispersive X-ray confirmed the presence of distinct NPs in the range of 5–50 nm containing Ag. Selected area electron diffraction and powder X-ray diffraction patterns of the silver NPs showed Bragg reflections, characteristic of crystalline face-centered cubic structure of Ag0 and cubic structure of Ag2O. Root system of intact plants raised under sterile conditions also generated Ag0/Ag2O-NPs under strict sterile conditions in a manner similar to that recorded under non-sterile conditions. This revealed the inbuilt potential of root system to generate Ag0/Ag2O-NPs independent of any microorganism. Roots of intact plants reduced triphenyltetrazolium to triphenylformazon and impermeable ferricyanide to ferrocyanide, suggesting involvement of plasma membrane bound dehydrogenases in reduction of Ag+ and formation of Ag0/Ag2O-NPs. Root enzyme extract reduced triphenyltetrazolium to triphenylformazon and Ag+ to Ag0 in presence of NADH, clearly establishing potential of dehydrogenases to reduce Ag+ to Ag0, which generate Ag0/Ag2O-NPs. Findings presented in this manuscript put forth a novel, simple

  7. Investigation of seasonal dynamics of β- and γ-radiation Helds vertical profile in the surface atmospheric layer

    NASA Astrophysics Data System (ADS)

    Ryabkina, K. S.; Kondratyeva, A. G.; Nagorskiy, P. M.; Yakovleva, V. S.

    2016-06-01

    This paper is devoted to the seasonal dynamics of β- and γ-radiation field vertical profile in the surface atmospheric layer study. The findings revealed the following: a) significant seasonal variation in vertical distribution characteristics fields β- and γ-radiation b) reduced β-radiation flux density and γ-radiation dose with increasing height is maintained in the range of spring and fall, namely, starting with snow melt and finishing its setting; c) distortion vertical profile in the winter season, an inverse relationship β-flux density and dose rate of γ-radiation from the heights above the earth's surface was registered.

  8. Leaky-Wave Radiations by Modulating Surface Impedance on Subwavelength Corrugated Metal Structures.

    PubMed

    Cai, Ben Geng; Li, Yun Bo; Ma, Hui Feng; Jiang, Wei Xiang; Cheng, Qiang; Cui, Tie Jun

    2016-01-01

    One-dimensional (1D) subwavelength corrugated metal structures has been described to support spoof surface plasmon polaritons (SPPs). Here we demonstrate that a periodically modulated 1D subwavelength corrugated metal structure can convert spoof SPPs to propagating waves. The structure is fed at the center through a slit with a connected waveguide on the input side. The subwavelength corrugated metal structure on the output surface is regarded as metasurface and modulated periodically to realize the leaky-wave radiation at the broadside. The surface impedance of the corrugated metal structure is modulated by using cosine function and triangle-wave function, respectively, to reach the radiation effect. Full wave simulations and measuremental results are presented to validate the proposed design. PMID:27035269

  9. Leaky-Wave Radiations by Modulating Surface Impedance on Subwavelength Corrugated Metal Structures

    PubMed Central

    Cai, Ben Geng; Li, Yun Bo; Ma, Hui Feng; Jiang, Wei Xiang; Cheng, Qiang; Cui, Tie Jun

    2016-01-01

    One-dimensional (1D) subwavelength corrugated metal structures has been described to support spoof surface plasmon polaritons (SPPs). Here we demonstrate that a periodically modulated 1D subwavelength corrugated metal structure can convert spoof SPPs to propagating waves. The structure is fed at the center through a slit with a connected waveguide on the input side. The subwavelength corrugated metal structure on the output surface is regarded as metasurface and modulated periodically to realize the leaky-wave radiation at the broadside. The surface impedance of the corrugated metal structure is modulated by using cosine function and triangle-wave function, respectively, to reach the radiation effect. Full wave simulations and measuremental results are presented to validate the proposed design. PMID:27035269

  10. Measurement of Net Fluxes of Ammonium and Nitrate at the Surface of Barley Roots Using Ion-Selective Microelectrodes 1

    PubMed Central

    Henriksen, Gordon H.; Bloom, Arnold J.; Spanswick, Roger M.

    1990-01-01

    Neutral carrier-based liquid membrane ion-selective microelectrodes for NH4+ and NO3− were developed and used to investigate inorganic nitrogen acquisition in two varieties of barley, Hordeum vulgare L. cv Olli and H. vulgare L. cv Prato, originating in cold and warm climates, respectively. In the present paper, the methods used in the fabrication of ammonium- and nitrate-selective microelectrodes are described, and their application in the study of inorganic nitrogen uptake is demonstrated. Net ionic fluxes of NH4+ and NO3− were measured in the unstirred layer of solution immediately external to the root surface. The preference for the uptake of a particular ionic form was examined by measuring the net flux of the predominant form of inorganic nitrogen, with and without the alternative ion in solution. Net flux of NH4+ into the cold-adapted variety remained unchanged when equimolar concentrations (200 micromolar) of NH4+ and NO3− were present. Similarly, net flux of NO3− into the warm-adapted variety was not affected when NH4+ was also present in solution. The high temporal and spatial resolution afforded by ammonium- and nitrate-selective microelectrodes permits a detailed examination of inorganic nitrogen acquisition and its component ionic interactions. PMID:16667447

  11. Temperature changes on the root surfaces of mandibular incisors after an 810-nm high-intensity intracanal diode laser irradiation

    NASA Astrophysics Data System (ADS)

    da Fonseca Alvarez, Andrea; Moura-Netto, Cacio; Daliberto Frugoli, Alexandre; Fernando, Casemiro; Correa Aranha, Ana Cecilia; Davidowicz, Harry

    2012-01-01

    Temperature changes caused by laser irradiation can promote damage to the surrounding dental tissues. In this study, we evaluated the temperature changes of recently extracted human mandibular incisors during intracanal irradiation with an 810-nm diode laser at different settings. Fifty mandibular incisors were enlarged up to an apical size of ISO No. 40 file. After the final rinse with 17% ethylenediaminetetraacetic acid, 0.2% lauryl sodium sulfate biologic detergent, and sterile water, samples were irradiated with circular movements from apex to crown through five different settings of output power (1.5, 2.0, 2.5, 3.0, and 3.5 W) in continuous mode. The temperature changes were measured on both sides of the apical and middle root thirds using two thermopar devices. A temperature increase of 7 °C was considered acceptable as a safe threshold when applying the diode laser. Results: The results showed that only 3.5-W output power increased the outer surface temperature above the critical value. Conclusion: The recommended output power can be stipulated as equal to or less than 3 W to avoid overheating during diode laser irradiation on thin dentin walls.

  12. Desulfovibrio zosterae sp. nov., a new sulfate reducer isolated from surface-sterilized roots of the seagrass Zostera marina.

    PubMed

    Nielsen, J T; Liesack, W; Finster, K

    1999-04-01

    A sulfate-reducing bacterium, designated strain lacT, was isolated from surface-sterilized roots of the benthic macrophyte Zostera marina. Cells were motile by means of a single polar flagellum. Strain lacT utilized lactate, pyruvate, malate, ethanol, L-alanine, fumarate, choline and fructose with sulfate as electron acceptor. In addition, fumarate, pyruvate and fructose were also degraded without an external electron acceptor. Sulfate could be substituted with thiosulfate, sulfite and elemental sulfur. Optimal growth was observed between 32.5 and 34.5 degrees C, at an NaCl concentration of 0.2 M and in a pH range between 6.8 and 7.3. The G + C content of the DNA was 42.7 +/- 0.2 mol%. Desulfoviridin and catalase were present. Strain lacT contained c-type cytochromes. Comparative 16S rRNA gene sequence analysis and the fatty acid pattern grouped this isolate into the genus Desulfovibrio. However, strain lacT differs from all other described Desulfovibrio species on the bases of its 16S rRNA gene sequence, the G + C content, its cellular lipid pattern and the utilization pattern of substrates. These characteristics establish strain lacT (= DSM 11974T) as a novel species of the genus Desulfovibrio, for which the name Desulfovibrio zosterae sp. nov. is proposed.

  13. Observations of albedo and radiation balance over postforest land surfaces in the eastern Amazon Basin

    SciTech Connect

    Giambelluca, T.W.; Nullet, M.A.; Ziegler, A.D.

    1997-05-01

    Regional climatic change, including significant reductions in Amazon Basin evaporation and precipitation, has been predicted by numerical simulations of total tropical forest removal. These results have been shown to be very sensitive to the prescription of the albedo shift associated with conversion from forest to a replacement land cover. Modelers have so far chosen to use an {open_quotes}impoverished grassland{close_quotes} scenario to represent the postforest land surface. This choice maximizes the shifts in land surface parameters, especially albedo (fraction of incident shortwave radiation reflected by the surface). Recent surveys show secondary vegetation to be the dominant land cover for some deforested areas of the Amazon. This paper presents the results of field measurements of radiation flux over various deforested surfaces on a small farm in the eastern Amazonian state of Para. The albedo of fields in active use was as high as 0.176, slightly less than the 0.180 recently determined for Amazonian pasture and substantially less than the 0.19 commonly used in GCM simulations of deforestation. For 10-yr-old secondary vegetation, albedo was 0.135, practically indistinguishable from the recently published mean primary forest albedo of 0.134. Measurements of surface temperature and net radiation show that, despite similarity in albedo, secondary vegetation differs from primary forest in energy and mass exchange. The elevation of midday surface temperature above air temperature was found to be greatest for actively and recently farmed land, declining with time since abandonment. Net radiation was correspondingly lower for fields in active or recent use. Using land cover analyses of the region surrounding the study area for 1984, 1988, and 1991, the pace of change in regional-mean albedo is estimated to have declined and appears to be leveling at a value less than 0.03 above that of the original forest cover. 41 refs., 3 figs., 8 tabs.

  14. Role of Rhizobium endoglucanase CelC2 in cellulose biosynthesis and biofilm formation on plant roots and abiotic surfaces

    PubMed Central

    2012-01-01

    Background The synthesis of cellulose is among the most important but poorly understood biochemical processes, especially in bacteria, due to its complexity and high degree of regulation. In this study, we analyzed both the production of cellulose by all known members of the Rhizobiaceae and the diversity of Rhizobium celABC operon predicted to be involved in cellulose biosynthesis. We also investigated the involvement in cellulose production and biofilm formation of celC gene encoding an endoglucanase (CelC2) that is required for canonical symbiotic root hair infection by Rhizobium leguminosarum bv. trifolii. Results ANU843 celC mutants lacking (ANU843ΔC2) or overproducing cellulase (ANU843C2+) produced greatly increased or reduced amounts of external cellulose micro fibrils, respectively. Calcofluor-stained cellulose micro fibrils were considerably longer when formed by ANU843ΔC2 bacteria rather than by the wild-type strain, in correlation with a significant increase in their flocculation in batch culture. In contrast, neither calcofluor-stained extracellular micro fibrils nor flocculation was detectable in ANU843C2+ cells. To clarify the role of cellulose synthesis in Rhizobium cell aggregation and attachment, we analyzed the ability of these mutants to produce biofilms on different surfaces. Alteration of wild-type CelC2 levels resulted in a reduced ability of bacteria to form biofilms both in abiotic surfaces and in planta. Conclusions Our results support a key role of the CelC2 cellulase in cellulose biosynthesis by modulating the length of the cellulose fibrils that mediate firm adhesion among Rhizobium bacteria leading to biofilm formation. Rhizobium cellulose is an essential component of the biofilm polysaccharidic matrix architecture and either an excess or a defect of this “building material” seem to collapse the biofilm structure. These results position cellulose hydrolytic enzymes as excellent anti-biofilm candidates. PMID:22970813

  15. In situ investigation of the mechanisms of the transport to tissues of polycyclic aromatic hydrocarbons adsorbed onto the root surface of Kandelia obovata seedlings.

    PubMed

    Li, Ruilong; Zhu, Yaxian; Zhang, Yong

    2015-06-01

    A novel method for in situ determination of the polycyclic aromatic hydrocarbons (PAHs) adsorbed onto the root surface of Kandelia obovata seedlings was established using laser-induced time-resolved nanosecond fluorescence spectroscopy (LITRF). The linear dynamic ranges for the established method were 1.5-1240ng/spot for phenanthrene, 1.0-1360ng/spot for pyrene and 5.0-1220ng/spot for benzo[a]pyrene. Then, the mechanisms of PAHs transport from the Ko root surface to tissues were investigated. The three-phase model including fast, slow and very slow fractions was superior to the single or dual-phase model to describe the PAHs transport processes. Moreover, the fast fraction of PAHs transport process was mainly due to passive movement, while the slow and very slow fractions were not. Passive movement was the main process of B[a]P adsorbed onto Ko root surface transport to tissues. In addition, the extent of the PAHs transport to Ko root tissues at different salinity were evaluated.

  16. Near-field radiative heat transfer between arbitrarily shaped objects and a surface

    NASA Astrophysics Data System (ADS)

    Edalatpour, Sheila; Francoeur, Mathieu

    2016-07-01

    A fluctuational electrodynamics-based formalism for calculating near-field radiative heat transfer between objects of arbitrary size and shape and an infinite surface is presented. The surface interactions are treated analytically via Sommerfeld's theory of electric dipole radiation above an infinite plane. The volume integral equation for the electric field is discretized using the thermal discrete dipole approximation (T-DDA). The framework is verified against exact results in the sphere-surface configuration and is applied to analyze near-field radiative heat transfer between a complex-shaped probe and an infinite plane, both made of silica. It is found that, when the probe tip size is approximately equal to or smaller than the gap d separating the probe and the surface, coupled localized surface phonon (LSPh)-surface phonon-polariton (SPhP) mediated heat transfer occurs. In this regime, the net spectral heat rate exhibits four resonant modes due to LSPhs along the minor axis of the probe, while the net total heat rate in the near field follows a d-0.3 power law. Conversely, when the probe tip size is much larger than the separation gap d , heat transfer is mediated by SPhPs, resulting in two resonant modes in the net spectral heat rate, corresponding to those of a single emitting silica surface, while the net total heat rate approaches a d-2 power law. It is also demonstrated that a complex-shaped probe can be approximated by a prolate spheroidal electric dipole when the thermal wavelength is larger than the major axis of the spheroidal dipole and when the separation gap d is much larger than the radius of curvature of the dipole tip facing the surface.

  17. EFFECT OF SURFACE PREPARATION TECHNIQUE ON THE RADIATION DETECTOR PERFORMANCEOF CDZNTE

    SciTech Connect

    Duff, M

    2007-05-23

    Synthetic CdZnTe (CZT) semiconducting crystals are highly suitable for the room temperature-based detection of gamma radiation. The surface preparation of Au contacts on surfaces of CZT detectors is typically conducted after (1) polishing to remove artifacts from crystal sectioning and (2) chemical etching, which removes residual mechanical surface damage however etching results in a Te rich surface layer that is prone to oxidize. Our studies show that CZT surfaces that are only polished (as opposed to polished and etched) can be contacted with Au and will yield lower surface currents. Due to their decreased dark currents, these as-polished surfaces can be used in the fabrication of gamma detectors exhibiting a higher performance than polished and etched surfaces with relatively less peak tailing and greater energy resolution. CdZnTe or ''CZT'' crystals are attractive to use in homeland security applications because they detect radiation at room temperature and do not require low temperature cooling as with silicon- and germanium-based detectors. Relative to germanium and silicon detectors, CZT is composed of higher Z elements and has a higher density, which gives it greater ''stopping power'' for gamma rays making a more efficient detector. Single crystal CZT materials with high bulk resistivity ({rho}>10{sup 10} {Omega} x cm) and good mobility-lifetime products are also required for gamma-ray spectrometric applications. However, several factors affect the detector performance of CZT are inherent to the as grown crystal material such as the presence of secondary phases, point defects and the presence of impurities (as described in a literature review by R. James and researchers). These and other factors can limit radiation detector performance such as low resistivity, which causes a large electronic noise and the presence of traps and other heterogeneities, which result in peak tailing and poor energy resolution.

  18. Radiation induced surface modification and contamination for EUV lithography and fusion applications

    NASA Astrophysics Data System (ADS)

    Al-Ajlony, Al-Montaser Bellah

    Al-Montaser Bellah Al-Ajlony. Ph.D., Purdue University, May 2014. Radiation Induced Surface Modification and Contamination for EUV Lithography and Fusion Applications. Major Professor: Ahmed Hassanein. The effect of ionizing radiation on materials surfaces is of major interest for many engineering applications. The importance of this topic rises from the severity of the implications that a surface at a certain application might suffer due its interaction with some sort of ionizing radiation. The severity of implication is not always related to the severity of the radiation, in many applications the concern comes from the over-sensitivity of the surface to a low doses of radiations. One example of these sensitive applications is the extreme ultraviolet (EUV) induced surface contaminations of the optics in EUV lithography devices. In this application, a small dose of ionizing radiation (EUV at 13.5 nm wavelength) can cause slight change in the chemical composition of the irradiated surface. This change in chemical composition can cause large change in the surface optical properties of the irradiated surface (EUV optics). This degradation in reflectivity is an issue that needs to be avoided. On the other extreme where intense radiation is implemented, the main concern of the radiation-surface interaction comes from the severity of the irradiation process. The plasma-facing component (PFC) in future thermonuclear devices represent the ultimate example where the materials might be exposed to severe irradiation processes. Under such extreme irradiation processes, some candidate PFC materials exhibit the formation of very fine and fragile nanostructure (Fuzz) that can be washed out into the fusion device plasma and stop the fusion reaction. These two extreme examples of the radiation-surface interaction were selected to be my PhD research topic. The change in chemical properties of Ru surface during exposure to a 13.5 nm wavelength of EUV light radiation was investigated

  19. Measurement of the surface wavelength distribution of narrow-band radiation by a colorimetric method

    SciTech Connect

    Kraiskii, A V; Mironova, T V; Sultanov, T T

    2010-09-10

    A method is suggested for determining the wavelength of narrow-band light from a digital photograph of a radiating surface. The digital camera used should be appropriately calibrated. The accuracy of the wavelength measurement is better than 1 nm. The method was tested on the yellow doublet of mercury spectrum and on the adjacent continuum of the incandescent lamp radiation spectrum. By means of the method suggested the homogeneity of holographic sensor swelling was studied in stationary and transient cases. (laser applications and other topics in quantum electronics)

  20. A three dimensional radiative transfer method for optical remote sensing of vegetated land surfaces

    NASA Technical Reports Server (NTRS)

    Asrar, Ghassem; Myneni, Ranga B.; Choudhury, Bhaskar J.

    1991-01-01

    In the application of remote sensing at optical wavelengths to vegetated surfaces from satellite borne high resolution instruments, an understanding of the various physical mechanisms that contribute to the measured signal is important. A numerical method of solving the radiative transfer equation in three dimensions is reported. The reliability of coding and accuracy of the algorithm are evaluated by benchmarching. Parametrization of the methods and results of a simulation are presented. The method is tested with experimental data of canopy bidirectional reflectance factors. The effect of spatial heterogeneity on the relationship between the simple ratio and normalized vrs absorbed Photosynthetically Active Radiation (PAR) is discussed.

  1. Average latitudinal variation in ultraviolet radiation at the earth's surface. [biological sensitivity and dosage

    NASA Technical Reports Server (NTRS)

    Johnson, F. S.; Mo, T.; Green, A. E. S.

    1976-01-01

    Tabulated values are presented for ultraviolet radiation at the earth's surface as a function of wavelength, latitude, and season, for clear sky and seasonally and latitudinally averaged ozone amounts. These tabulations can be combined with any biological sensitivity function in order to obtain the seasonal and latitudinal variation of the corresponding effective doses. The integrated dosages, based on the erythemal sensitivity curve and on the Robertson-Berger sunburn-meter sensitivity curve, have also been calculated, and these are found to vary with latitude and season in very nearly the same way as 307 and 314 nm radiation, respectively.

  2. Air Temperature estimation from Land Surface temperature and solar Radiation parameters

    NASA Astrophysics Data System (ADS)

    Lazzarini, Michele; Eissa, Yehia; Marpu, Prashanth; Ghedira, Hosni

    2013-04-01

    Air Temperature (AirT) is a fundamental parameter in a wide range of applications such as climate change studies, weather forecast, energy balance modeling, efficiency of Photovoltaic (PV) solar cells, etc. Air temperature data are generally obtained through regular measurements from meteorological stations. The distribution of these stations is normally sparse, so the spatial pattern of this parameter cannot be accurately estimated by interpolation methods. This work investigated the relationship between Air Temperature measured at meteorological stations and spatially contiguous measurements derived from Remote Sensing techniques, such as Land Surface Temperature (LST) maps, emissivity maps and shortwave radiation maps with the aim of creating a continuous map of AirT. For LST and emissivity, MSG-SEVIRI LST product from Land Surface Analysis Satellite Applications Facility (LSA-SAF) has been used. For shortwave radiation maps, an Artificial Neural Networks ensemble model has been developed and previously tested to create continuous maps from Global Horizontal Irradiance (GHI) point measurements, utilizing six thermal channels of MSG-SEVIRI. The testing sites corresponded to three meteorological stations located in the United Arab Emirates (UAE), where in situ measurements of Air Temperature were available. From the starting parameters, energy fluxes and net radiation have been calculated, in order to have information on the incoming and outgoing long-wave radiation and the incoming short-wave radiation. The preliminary analysis (day and Night measurements, cloud free) showed a strong negative correlation (0.92) between Outgoing long-wave radiation - GHI and LST- AirT, with a RMSE of 1.84 K in the AirT estimation from the initial parameters. Regression coefficients have been determined and tested on all the ground stations. The analysis also demonstrated the predominant impact of the incoming short-wave radiation in the AirT hourly variation, while the incoming

  3. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    NASA Astrophysics Data System (ADS)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  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. Macroscopic Degeneracy of Zero-Mode Rotating Surface States in 3D Dirac and Weyl Semimetals under Radiation.

    PubMed

    González, José; Molina, Rafael A

    2016-04-15

    We investigate the development of novel surface states when 3D Dirac or Weyl semimetals are placed under circularly polarized electromagnetic radiation. We find that the hybridization between inverted Floquet bands opens, in general, a gap, which closes at so-called exceptional points found for complex values of the momentum. This corresponds to the appearance of midgap surface states in the form of evanescent waves decaying from the surface exposed to the radiation. We observe a phenomenon reminiscent of Landau quantization by which the midgap surface states get a large degeneracy proportional to the radiation flux traversing the surface of the semimetal. We show that all of these surface states carry angular current, leading to an angular modulation of their charge that rotates with the same frequency of the radiation, which should manifest in the observation of a macroscopic chiral current in the irradiated surface. PMID:27127980

  6. Relative ultraviolet spectral intensity of direct solar radiation, sky radiation and surface reflections. Relative contribution of natural sources to the outdoor UV irradiation of man.

    PubMed

    Kromann, N; Wulf, H C; Eriksen, P; Brodthagen, H

    1986-04-01

    Relative measurements of UVA and UVB radiation from the sun and the sky, as well as the reflected intensity from various land and water surfaces, have been carried out in the Copenhagen area. The measurements were taken in January and in the period April through July and supplemented by measurements in Greenland during May. Likewise, the angular distribution of direct solar radiation and sky radiation close to the direction of the sun was measured with a 0.5 degree field of view. Absolute UV irradiances were measured with detector-filter combinations. Calculations of the relative contributions of direct solar radiation, sky radiation and reflected radiation to the irradiation of a standing person show, in particular, that if seawater with waves is the surrounding scene, its reflected radiation will account for more than 10% of the received UV dose.

  7. A comparative scanning electron microscopy study between hand instrument, ultrasonic scaling and erbium doped:Yttirum aluminum garnet laser on root surface: A morphological and thermal analysis

    PubMed Central

    Mishra, Mitul Kumar; Prakash, Shobha

    2013-01-01

    Background and Objectives: Scaling and root planing is one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time consuming. In search of more efficient and less difficult instrumentation, investigators have proposed lasers as an alternative or as adjuncts to scaling and root planing. Hence, the purpose of the present study was to evaluate the effectiveness of erbium doped: Yttirum aluminum garnet (Er:YAG) laser scaling and root planing alone or as an adjunct to hand and ultrasonic instrumentation. Subjects and Methods: A total of 75 freshly extracted periodontally involved single rooted teeth were collected. Teeth were randomly divided into five treatment groups having 15 teeth each: Hand scaling only, ultrasonic scaling only, Er:YAG laser scaling only, hand scaling + Er:YAG laser scaling and ultrasonic scaling + Er:YAG laser scaling. Specimens were subjected to scanning electron microscopy and photographs were evaluated by three examiners who were blinded to the study. Parameters included were remaining calculus index, loss of tooth substance index, roughness loss of tooth substance index, presence or absence of smear layer, thermal damage and any other morphological damage. Results: Er:YAG laser treated specimens showed similar effectiveness in calculus removal to the other test groups whereas tooth substance loss and tooth surface roughness was more on comparison with other groups. Ultrasonic treated specimens showed better results as compared to other groups with different parameters. However, smear layer presence was seen more with hand and ultrasonic groups. Very few laser treated specimens showed thermal damage and morphological change. Interpretation and Conclusion: In our study, ultrasonic scaling specimen have shown root surface clean and practically unaltered. On the other hand, hand instrument have produced a plane surface, but removed more

  8. Surface radiation climatology for Ny-Ålesund, Svalbard (78.9° N), basic observations for trend detection

    NASA Astrophysics Data System (ADS)

    Maturilli, Marion; Herber, Andreas; König-Langlo, Gert

    2015-04-01

    At Ny-Ålesund (78.9° N), Svalbard, surface radiation measurements of up- and downward short- and longwave radiation are operated since August 1992 in the frame of the Baseline Surface Radiation Network (BSRN), complemented with surface and upper air meteorology since August 1993. The long-term observations are the base for a climatological presentation of the surface radiation data. Over the 21-year observation period, ongoing changes in the Arctic climate system are reflected. Particularly, the observations indicate a strong seasonality of surface warming and related changes in different radiation parameters. The annual mean temperature at Ny-Ålesund has risen by +1.3 ± 0.7 K per decade, with a maximum seasonal increase during the winter months of +3.1 ± 2.6 K per decade. At the same time, winter is also the season with the largest long-term changes in radiation, featuring an increase of +15.6 ± 11.6 Wm-2 per decade in the downward longwave radiation. Furthermore, changes in the reflected solar radiation during the months of snow melt indicate an earlier onset of the warm season by about 1 week compared to the beginning of the observations. The supplementary dataset of Ny-Ålesund surface radiation measurements (available at http://dx.doi.org/10.1594/PANGAEA.150000) provides a valuable data source for the validation of satellite instruments and climate models.

  9. Factors controlling spatio-temporal variation in carbon dioxide efflux from surface litter, roots, and soil organic matter at four rain forest sites in the eastern Amazon

    NASA Astrophysics Data System (ADS)

    Metcalfe, D. B.; Meir, P.; AragãO, L. E. O. C.; Malhi, Y.; da Costa, A. C. L.; Braga, A.; GonçAlves, P. H. L.; de Athaydes, J.; de Almeida, S. S.; Williams, M.

    2007-12-01

    This study explored biotic and abiotic causes for spatio-temporal variation in soil respiration from surface litter, roots, and soil organic matter over one year at four rain forest sites with different vegetation structures and soil types in the eastern Amazon, Brazil. Estimated mean annual soil respiration varied between 13-17 t C ha-1 yr-1, which was partitioned into 0-2 t C ha-1 yr-1 from litter, 6-9 t C ha-1 yr-1 from roots, and 5-6 t C ha-1 yr-1 from soil organic matter. Litter contribution showed no clear seasonal change, though experimental precipitation exclusion over a one-hectare area was associated with a ten-fold reduction in litter respiration relative to unmodified sites. The estimated mean contribution of soil organic matter respiration fell from 49% during the wet season to 32% in the dry season, while root respiration contribution increased from 42% in the wet season to 61% during the dry season. Spatial variation in respiration from soil, litter, roots, and soil organic matter was not explained by volumetric soil moisture or temperature. Instead, spatial heterogeneity in litter and root mass accounted for 44% of observed spatial variation in soil respiration (p < 0.001). In particular, variation in litter respiration per unit mass and root mass accounted for much of the observed variation in respiration from litter and roots, respectively, and hence total soil respiration. This information about patterns of, and underlying controls on, respiration from different soil components should assist attempts to accurately model soil carbon dioxide fluxes over space and time.

  10. Polyglycerol dendrimers immobilized on radiation grafted poly-HEMA hydrogels: Surface chemistry characterization and cell adhesion

    NASA Astrophysics Data System (ADS)

    Higa, Olga Z.; Faria, Henrique Antonio Mendonça; de Queiroz, Alvaro A. A.

    2014-05-01

    Radiation induced grafting of poly(2-hydroxyethylmethacrylate) (PHEMA) on low density polyethylene (LDPE) films and subsequent immobilization of poly(glycerol) dendrimer (PGLD) has been performed with the aim to improve cell adhesion and proliferation on the surface of the polymer, in order to enhance their properties for bone tissue engineering scaffolding applications. Radiation grafting of PHEMA onto LDPE was promoted by γ-ray radiation. The covalent immobilization of PGLD on LDPE-g-PHEMA surface was performed by using a dicyclohexyl carbodiimide (DCC)/N,N-dimethylaminopyridine (DMAP) method. The occurrence of grafting polymerization of PHEMA and further immobilization of PGLD was quantitatively confirmed by photoelectron spectroscopy (XPS) and fluorescence, respectively. The LDPE-g-PHEMA surface topography after PGLD coupling was studied by atomic force microscopy (AFM). The hydrophilicity of the LDPE-g-PHEMA film was remarkably improved compared to that of the ungrafted LDPE. The core level XPS ESCA spectrum of PHEMA-grafted LDPE showed two strong peaks at 286.6 eV (from hydroxyl groups and ester groups) and 289.1 eV (from ester groups) due to PHEMA brushes grafted onto LDPE surfaces. The results from the cell adhesion studies show that MCT3-E1 cells tended to spread more slowly on the LDPE-g-PHEMA than on the LDPE-g-PHEMA-i-PGLD.

  11. Aerosols attenuating the solar radiation collected by solar tower plants: The horizontal pathway at surface level

    NASA Astrophysics Data System (ADS)

    Elias, Thierry; Ramon, Didier; Dubus, Laurent; Bourdil, Charles; Cuevas-Agulló, Emilio; Zaidouni, Taoufik; Formenti, Paola

    2016-05-01

    Aerosols attenuate the solar radiation collected by solar tower plants (STP), along two pathways: 1) the atmospheric column pathway, between the top of the atmosphere and the heliostats, resulting in Direct Normal Irradiance (DNI) changes; 2) the grazing pathway close to surface level, between the heliostats and the optical receiver. The attenuation along the surface-level grazing pathway has been less studied than the aerosol impact on changes of DNI, while it becomes significant in STP of 100 MW or more. Indeed aerosols mostly lay within the surface atmospheric layer, called the boundary layer, and the attenuation increases with the distance covered by the solar radiation in the boundary layer. In STP of 100 MW or more, the distance between the heliostats and the optical receiver becomes large enough to produce a significant attenuation by aerosols. We used measured aerosol optical thickness and computed boundary layer height to estimate the attenuation of the solar radiation at surface level at Ouarzazate (Morocco). High variabilities in aerosol amount and in vertical layering generated a significant magnitude in the annual cycle and significant inter-annual changes. Indeed the annual mean of the attenuation caused by aerosols over a 1-km heliostat-receiver distance was 3.7% in 2013, and 5.4% in 2014 because of a longest desert dust season. The monthly minimum attenuation of less than 3% was observed in winter and the maximum of more than 7% was observed in summer.

  12. Multi-Decadal Change of Atmospheric Aerosols and their Effect on Surface Radiation

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Streets, David; Wild, Martin; Qian, Yun; Yu, Hongbin; Tan, Qian; Bian, Huisheng; Wang, Weiguo

    2011-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model, GOCART, along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007 during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. Particularly: (1) We compare the model calculated clear sky downward radiation at the surface with surface network data from BSRN and CMA (2) We compare the model and surface data with satellite derived downward radiation products from ISCCP and SRS (3) We analyze the long-term global and regional aerosol trends in major anthropogenic source regions (North America, Europe, Asia) that have been experiencing considerable changes of emissions during the three decades, dust and biomass burning regions that have large interannual variability, downwind regions that are directly affected by the changes in the source area, and remote regions that are considered to representing "background" conditions. The comparisons and methods from this study can be applied to multiple model analysis in the AeroCom framework.

  13. A new formulation of electromagnetic wave scattering using an on-surface radiation boundary condition approach

    NASA Technical Reports Server (NTRS)

    Kriegsmann, Gregory A.; Taflove, Allen; Umashankar, Koradar R.

    1987-01-01

    A new formulation of electromagnetic wave scattering by convex, two-dimensional conducting bodies is reported. This formulation, called the on-surface radiation condition (OSRC) approach, is based upon an expansion of the radiation condition applied directly on the surface of a scatterer. It is now shown that application of a suitable radiation condition directly on the surface of a convex conducting scatterer can lead to substantial simplification of the frequency-domain integral equation for the scattered field, which is reduced to just a line integral. For the transverse magnetic case, the integrand is known explicitly. For the transverse electric case, the integrand can be easily constructed by solving an ordinary differential equation around the scatterer surface contour. Examples are provided which show that OSRC yields computed near and far fields which approach the exact results for canonical shapes such as the circular cylinder, square cylinder, and strip. Electrical sizes for the examples are ka = 5 and ka = 10. The new OSRC formulation of scattering may present a useful alternative to present integral equation and uniform high-frequency approaches for convex cylinders larger than ka = 1. Structures with edges or corners can also be analyzed, although more work is needed to incorporate the physics of singular currents at these discontinuities. Convex dielectric structures can also be treated using OSRC.

  14. High resolution surface solar radiation patterns over Eastern Mediterranean: Satellite, ground-based, reanalysis data and radiative transfer simulations

    NASA Astrophysics Data System (ADS)

    Alexandri, G.; Georgoulias, A.; Meleti, C.; Balis, D.

    2013-12-01

    Surface solar radiation (SSR) and its long and short term variations play a critical role in the modification of climate and by extent of the social and financial life of humans. Thus, SSR measurements are of primary importance. SSR is measured for decades from ground-based stations for specific spots around the planet. During the last decades, satellite observations allowed for the assessment of the spatial variability of SSR at a global as well as regional scale. In this study, a detailed spatiotemporal view of the SSR over Eastern Mediterranean is presented at a high spatial resolution. Eastern Mediterranean is affected by various aerosol types (continental, sea, dust and biomass burning particles) and encloses countries with significant socioeconomical changes during the last decades. For the aims of this study, SSR data from satellites (Climate Monitoring Satellite Application Facility - CM SAF) and our ground station in Thessaloniki, a coastal city of ~1 million inhabitants in northern Greece, situated in the heart of Eastern Mediterranean (Eppley Precision pyranometer and Kipp & Zonen CM-11 pyranometer) are used in conjunction with radiative transfer simulations (Santa Barbara DISORT Atmospheric Radiative Transfer - SBDART). The CM SAF dataset used here includes monthly mean SSR observations at a high spatial resolution of 0.03x0.03 degrees for the period 1983-2005. Our ground-based SSR observations span from 1983 until today. SBDART radiative transfer simulations were implemented for a number of spots in the area of study in order to calculate the SSR. High resolution (level-2) aerosol and cloud data from MODIS TERRA and AQUA satellite sensors were used as input, as well as ground-based data from the AERONET. Data from other satellites (Earth Probe TOMS, OMI, etc) and reanalysis projects (ECMWF) were used where needed. The satellite observations, the ground-based measurements and the model estimates are validated against each other. The good agreement

  15. Effect of wing sweep, angle of attack, Reynolds number, and wing root fillet on the interference heating to the wing windward surface of an entry vehicle configuration

    NASA Technical Reports Server (NTRS)

    Clark, L. E.

    1972-01-01

    The phase-change-coating technique was used to study the interference heating to the windward surface of 14 deg, 25 deg, and 50 deg swept wings of an entry vehicle configuration. One wing root of each model was faired to the fuselage with a fillet. Tests were made at Mach 8 at angles of attack of 0 deg, 20 deg, 40 deg, and 60 deg and at free-stream Reynolds numbers based on model length of 0.47 and 1.7 million. Bow shock impingement heating was found to increase in magnitude and affected area with increasing angle of attack until at a higher angle of attack it decreases; this angle of attack is lower for a 50 deg swept wing. Wing root interference heating was found to increase with angle of attack up to 40 deg and then to remain approximately constant. Consequently, wing root interference heating becomes the major type of interference heating at large angles of attack, and this occurs at a lower angle of attack for the highest sweep angle. A wing leading-edge root fillet reduces the peak in wing root interference heating near the leading edge, and increasing Reynolds number increases the level of interference heating.

  16. PASSIVATION OF SEMICONDUCTOR SURFACES FOR IMPROVED RADIATION DETECTORS: X-RAY PHOTOEMISSION ANALYSIS

    SciTech Connect

    Nelson, A; Conway, A; Reinhardt, C; Ferreira, J; Nikolic, R; Payne, S

    2007-12-10

    Surface passivation of device-grade radiation detector materials was investigated using x-ray photoelectron spectroscopy in combination with transport property measurements before and after various chemical treatments. Specifically Br-MeOH (2% Br), KOH with NH{sub 4}F/H{sub 2}O{sub 2} and NH{sub 4}OH solutions were used to etch, reduce and oxidize the surface of Cd{sub (1-x)}Zn{sub x}Te semiconductor crystals. Scanning electron microscopy was used to evaluate the resultant microscopic surface morphology. Angle-resolved high-resolution photoemission measurements on the valence band electronic structure and core lines were used to evaluate the surface chemistry of the chemically treated surfaces. Metal overlayers were then deposited on these chemically treated surfaces and the I-V characteristics measured. The measurements were correlated to understand the effect of interface chemistry on the electronic structure at these interfaces with the goal of optimizing the Schottky barrier height for improved radiation detector devices.

  17. Polarization radiation in the planetary atmosphere delimited by a heterogeneous diffusely reflecting surface

    NASA Technical Reports Server (NTRS)

    Strelkov, S. A.; Sushkevich, T. A.

    1983-01-01

    Spatial frequency characteristics (SFC) and the scattering functions were studied in the two cases of a uniform horizontal layer with absolutely black bottom, and an isolated layer. The mathematical model for these examples describes the horizontal heterogeneities in a light field with regard to radiation polarization in a three dimensional planar atmosphere, delimited by a heterogeneous surface with diffuse reflection. The perturbation method was used to obtain vector transfer equations which correspond to the linear and nonlinear systems of polarization radiation transfer. The boundary value tasks for the vector transfer equation that is a parametric set and one dimensional are satisfied by the SFC of the nonlinear system, and are expressed through the SFC of linear approximation. As a consequence of the developed theory, formulas were obtained for analytical calculation of albedo in solving the task of dissemination of polarization radiation in the planetary atmosphere with uniform Lambert bottom.

  18. Preparation of clean InP(100) surfaces studied by synchrotron radiation photoemission

    NASA Astrophysics Data System (ADS)

    Sun, Yun; Liu, Zhi; Machuca, Francisco; Pianetta, Piero; Spicer, William E.

    2003-01-01

    The chemical cleaning of indium phosphide (InP),(100) surfaces is studied systematically by using photoemission electron spectroscopy. In order to achieve the necessary surface sensitivity and spectral resolution, synchrotron radiation with photon energies ranging from 60 to 600 eV are used to study the indium 4d, phosphorus 2p, carbon 1s, and oxygen 1s core levels, and the valence band. Typical H2SO4:H2O2:H2O solutions used to etch GaAs(100) surfaces are applied to InP(100) surfaces. It is found that the resulting surface species are significantly different from those found on GaAs(100) surfaces and that a second chemical cleaning step using a strong acid is required to remove residual surface oxide. This two-step cleaning process leaves the surface oxide free and with approximately 0.4 ML of elemental phosphorus, which is removed by vacuum annealing. The carbon coverage is also reduced dramatically from approximately 1 to about 0.05 ML. The chemical reactions are investigated, the resulting InP surface species at different cleaning stages are determined, and the optimum cleaning procedure is presented.

  19. The effect of CO2 laser irradiation plus fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement or composite resin restorations

    NASA Astrophysics Data System (ADS)

    Rodrigues, S. R.; Moraes, M.; Hanashiro, F. S.; Youssef, M. N.; Brugnera Junior, A.; Nobre-dos-Santos, M.; de Souza-Zaroni, W. C.

    2016-02-01

    Although the cariostatic effects of CO2 laser on the root surface have been shown, there is scarce information regarding its effects on root secondary caries. The objective of this research was to investigate the effect of the association of CO2 laser and a fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to composite-resin or glass-ionomer-cement restorations. Dental blocks of human roots were divided into two groups: composite resin (CR) or glass ionomer cement (GIC). Subsequently, the blocks were divided into four subgroups (n  =  10): C, non-fluoride dentifrice; FD, fluoride dentifrice; L, CO2 laser with an energy density of 6.0 J cm-2  +  non-fluoride dentifrice; and L  +  FD, CO2 laser  +  fluoride dentifrice. The blocks were subjected to pH cycling to simulate a high cariogenic challenge. Dental demineralization around the restorations was quantified by microhardness analysis. The results were subjected to analysis of variance (ANOVA) and the Tukey-Kramer test (p  ⩽  0.05). As for mineral loss, it can be observed that all the groups that were treated with a fluoride dentifrice and laser, used alone or not, were statistically similar and superior to the RC-C group. It was concluded that CO2 laser irradiation and a fluoride dentifrice used alone or combined with each other are efficient surface treatments for preventing secondary root caries, regardless of the restorative material used.

  20. Effect of Er: YAG or Nd:YAG Laser Exposure on Fluorosed and Non-Fluorosed Root Surfaces: An In Vitro Study

    PubMed Central

    Ghosh, Saubhik; Dhingra, Kunaal; Patil, Roopa

    2015-01-01

    Background and aims: Fluorosis affects tooth mineralization. The therapeutic benefit provided by lasers on fluorosed and non fluorosed cementum requires studying and comparing. The aim of this study was to evaluate and compare the root surface changes following Er:YAG or Nd:YAG laser irradiation on periodontally healthy fluorosed versus non-fluorosed teeth by scanning electron microscopy (SEM). Materials and methods: A total of 76 periodontally healthy fluorosed (FH) and non-fluorosed (NFH) teeth specimens were included in this study. In one group, the experimental root specimens were irradiated using Er:YAG or with Nd:YAG laser in the other. A SEM evaluation was performed to assess the laser induced ultra structural changes in the root surface followed by statistical analysis using Fisher's exact test. Results: It was observed that both FH and NFH groups were similarly affected by Nd:YAG or Er:YAG laser. However, the former caused more surface changes than the latter on melting of surface (p=0.12 for FH and p=0.08 for NFH), and Er:YAG laser caused more smear layer formation (p=0.51 for FH and p=0.16 for NFH). Conclusion: Results suggest that undesirable morphological changes were observed almost similarly in FH and NFH groups using Er:YAG or Nd:YAG laser. Hence further in-vitro studies at lower energy settings followed by clinical trials are required in this aspect. PMID:26246689

  1. A contactless methodology of picking up micro-particles from rigid surfaces by acoustic radiation force.

    PubMed

    Jia, Kun; Yang, Keji; Fan, Zongwei; Ju, Bing-Feng

    2012-01-01

    Controlled movement and pick up of small object from a rigid surface is a primary challenge in many applications. In this paper, a contactless methodology of picking up micro-particles within deionized water from rigid surfaces by acoustic radiation force is presented. In order to achieve this, an acoustic radiation force was generated by 1.75 MHz transducers. A custom built setup facilitates the optimization of the sound field by varying the parameters such as sound source size and source position. The three-dimensional pressure distributions are measured and its relative sound field is also characterized accordingly. The standing wave field has been formed and it is mainly composed of two obliquely incident plane waves and their reflectors. We demonstrated the gripping and positioning of silica beads, SiO(2), and aluminum micro-particles of 100 μm to 500 μm in size with this method using acoustic radiation force. The acoustic radiation force generated is well controlled, contactless, and in the tens of nano-Newton range which allowed us to manipulate relative big micro objects such as MEMS components as well as moving objects such as living cells. The proposed method provided an alternative form of contactless operating environment with scalable dimensions suitable for the manipulating of small objects. This permits high-throughput processing and reduction in time required for MEMS assembling, cell biomechanics, and biotechnology applications.

  2. A contactless methodology of picking up micro-particles from rigid surfaces by acoustic radiation force

    NASA Astrophysics Data System (ADS)

    Jia, Kun; Yang, Keji; Fan, Zongwei; Ju, Bing-Feng

    2012-01-01

    Controlled movement and pick up of small object from a rigid surface is a primary challenge in many applications. In this paper, a contactless methodology of picking up micro-particles within deionized water from rigid surfaces by acoustic radiation force is presented. In order to achieve this, an acoustic radiation force was generated by 1.75 MHz transducers. A custom built setup facilitates the optimization of the sound field by varying the parameters such as sound source size and source position. The three-dimensional pressure distributions are measured and its relative sound field is also characterized accordingly. The standing wave field has been formed and it is mainly composed of two obliquely incident plane waves and their reflectors. We demonstrated the gripping and positioning of silica beads, SiO2, and aluminum micro-particles of 100 μm to 500 μm in size with this method using acoustic radiation force. The acoustic radiation force generated is well controlled, contactless, and in the tens of nano-Newton range which allowed us to manipulate relative big micro objects such as MEMS components as well as moving objects such as living cells. The proposed method provided an alternative form of contactless operating environment with scalable dimensions suitable for the manipulating of small objects. This permits high-throughput processing and reduction in time required for MEMS assembling, cell biomechanics, and biotechnology applications.

  3. Radiative Forcing at the Surface by Clouds, Aerosols, and Water Vapor Over Tropical Oceans

    NASA Astrophysics Data System (ADS)

    Key, E.; Minnett, P.; Szczodrak, G.; Caniaux, G.; Voss, K.; Bourras, D.

    2007-12-01

    Data from recent campaigns conducted in the tropical Atlantic and Indian Oceans provide thorough testbeds for determining the contribution of clouds, aerosols, and water vapor to surface radiative forcing, with particular focus on areas of extreme SST gradients. Oceanographic cruises conducted during the African Monsoon Multidisciplinary Analysis included sampling monsoon onset in the Gulf of Guinea, which was characterized nearshore by rain and haze, the latter being a combination of water vapor and continental and pollution aerosols. Offshore and nearer to the equatorial cold tongue, the ITCZ was the dominant northern hemisphere cloud feature, while drier, cooler air masses existed south of the equator. The R/V Ronald H. Brown, operating a north-south transect along 23 W, encountered both atmospheric tropical wave conditions as well as dry Saharan Air Layers. In the Indian Ocean, the N/O Le Suroit occupied a point station near a positive SST anomaly to observe the onset of convection associated with the MJO and strong diurnal warming signatures. Combining radiative and turbulent flux data with measured and modeled profiles of the marine and atmospheric boundary layer, the evolution and interaction of the total air-sea column is observed. Particular emphasis is placed on the radiative forcing of clouds, aerosols, and water vapor on the sea surface skin temperature, towards the improvement of current diurnal warming models, which simplify atmospheric radiative effects into a general cloud parameter.

  4. Transformation of surface plasmon polaritons to radiation in graphene in terahertz regime

    NASA Astrophysics Data System (ADS)

    Gong, Sen; Zhao, Tao; Sanderson, Matthew; Hu, Min; Zhong, Renbin; Chen, Xiaoxing; Zhang, Ping; Zhang, Chao; Liu, Shenggang

    2015-06-01

    We demonstrate a concept that allows direct excitation of surface plasmon polaritons (SPPs) by a moving electron bunch above a single layer graphene sheet deposited on a dielectric substrate without any additional coupling requirements. We show that if the two-dimensional current in the graphene is dominated by the third order nonlinear effect when the surface electric field exceeds a moderate strength of ˜5 kV/cm, the SPP mode can cross the light line although the group velocity remains much smaller than the speed of light. This effect gives rise to direct transformation of SPPs into radiation. The underlying mechanism of the crossing of the SPP dispersion into the light line is the energy shift of charged particles in the nonlinear regime and the finite transport scattering time in graphene. Both the energy and lifetime of the SPPs increase with the field intensity. The radiation intensity and frequency can be tuned with an AC bias.

  5. Manifestation of topological surface electron states in the photoelectromagnetic effect induced by terahertz laser radiation

    NASA Astrophysics Data System (ADS)

    Galeeva, A. V.; Egorova, S. G.; Chernichkin, V. I.; Tamm, M. E.; Yashina, L. V.; Rumyantsev, V. V.; Morozov, S. V.; Plank, H.; Danilov, S. N.; Ryabova, L. I.; Khokhlov, D. R.

    2016-09-01

    We demonstrate that measurements of the photoelectromagnetic effect using terahertz laser radiation may provide a unique opportunity to discriminate between the topological surface states and other highly conductive surface electron states. We performed a case study of mixed (Bi{}1-xIn x )2Se3 crystals undergoing a topological phase transformation due to the transition from the inverse to the direct electron energy spectrum in the crystal bulk at variation of the composition x. We show that for the topological insulator phase, the photoelectromagnetic effect amplitude is defined by the number of incident radiation quanta, whereas for the trivial insulator phase, it depends on the power in a laser pulse irrespective of its wavelength. We assume that such behavior is attributed to a strong damping of the electron-electron interaction in the topological insulator phase compared to the trivial insulator.

  6. Radiation protection using Martian surface materials in human exploration of Mars.

    PubMed

    Kim, M H; Thibeault, S A; Wilson, J W; Heilbronn, L; Kiefer, R L; Weakley, J A; Dueber, J L; Fogarty, T; Wilkins, R

    2001-01-01

    To develop materials for shielding astronauts from the hazards of GCR, natural Martian surface materials are considered for their potential as radiation shielding for manned Mars missions. The modified radiation fluences behind various kinds of Martian rocks and regolith are determined by solving the Boltzmann equation using NASA Langley's HZETRN code along with the 1977 Solar Minimum galactic cosmic ray environmental model. To develop structural shielding composite materials for Martian surface habitats, theoretical predictions of the shielding properties of Martian regolith/polyimide composites has been computed to assess their shielding effectiveness. Adding high-performance polymer binders to Martian regolith to enhance structural properties also enhances the shielding properties of these composites because of the added hydrogenous constituents. Heavy ion beam testing of regolith simulant/polyimide composites is planned to validate this prediction. Characterization and proton beam tests are performed to measure structural properties and to compare the shielding effects on microelectronic devices, respectively. PMID:11770542

  7. Effects of dust accumulation and removal on radiator surfaces on Mars

    SciTech Connect

    Gaier, J.R.; Perez-Davis, M.E.; Rutledge, S.K.; Hotes, D.; Olle, R.

    1991-01-01

    Tests were carried out to assess the impact of wind blown dust accumulation and abrasion on radiator surfaces on Mars. High emittance arc-textured copper (Cu) and niobium-1%-zirconium (Nb-1%Zr) samples were subjected to basaltic dust laden wind at Martian pressure (1000 Pa) at speeds varying from 19 to 97 m/s in the Martian Surface Wind Tunnel at NASA Ames Research Center. The effect of accumulated dust was also observed by pre-dusting some of the samples before the test. Radiator degradation was determined by measuring the change in the emittance after dust was deposited and/or removed. The principal mode of degradation was abrasion. Arc-textured Nb-1%Zr proved to be more susceptible to degradation than Cu, and pre-dusting appeared to have lessened the abrasion.

  8. Transformation of surface plasmon polaritons to radiation in graphene in terahertz regime

    SciTech Connect

    Gong, Sen; Zhao, Tao; Hu, Min; Zhong, Renbin; Chen, Xiaoxing; Zhang, Ping; Liu, Shenggang; Sanderson, Matthew; Zhang, Chao

    2015-06-01

    We demonstrate a concept that allows direct excitation of surface plasmon polaritons (SPPs) by a moving electron bunch above a single layer graphene sheet deposited on a dielectric substrate without any additional coupling requirements. We show that if the two-dimensional current in the graphene is dominated by the third order nonlinear effect when the surface electric field exceeds a moderate strength of ∼5 kV/cm, the SPP mode can cross the light line although the group velocity remains much smaller than the speed of light. This effect gives rise to direct transformation of SPPs into radiation. The underlying mechanism of the crossing of the SPP dispersion into the light line is the energy shift of charged particles in the nonlinear regime and the finite transport scattering time in graphene. Both the energy and lifetime of the SPPs increase with the field intensity. The radiation intensity and frequency can be tuned with an AC bias.

  9. Manifestation of topological surface electron states in the photoelectromagnetic effect induced by terahertz laser radiation

    NASA Astrophysics Data System (ADS)

    Galeeva, A. V.; Egorova, S. G.; Chernichkin, V. I.; Tamm, M. E.; Yashina, L. V.; Rumyantsev, V. V.; Morozov, S. V.; Plank, H.; Danilov, S. N.; Ryabova, L. I.; Khokhlov, D. R.

    2016-09-01

    We demonstrate that measurements of the photoelectromagnetic effect using terahertz laser radiation may provide a unique opportunity to discriminate between the topological surface states and other highly conductive surface electron states. We performed a case study of mixed (Bi{}1-xIn x )2Se3 crystals undergoing a topological phase transformation due to the transition from the inverse to the direct electron energy spectrum in the crystal bulk at variation of the composition x. We show that for the topological insulator phase, the photoelectromagnetic effect amplitude is defined by the number of incident radiation quanta, whereas for the trivial insulator phase, it depends on the power in a laser pulse irrespective of its wavelength. We assume that such behavior is attributed to a strong damping of the electron–electron interaction in the topological insulator phase compared to the trivial insulator.

  10. Electron Radiation Effects on Diethylsilane Covered Si (100) Surfaces Studied by Temperature Programmed Desorption

    NASA Astrophysics Data System (ADS)

    Petrany, Peter; Young, Vashawn; Kimberlin, Kevin R.; Lozano, Jose; Craig, James H.; Wang, Paul W.

    2003-03-01

    Ethylated silicon or germanium containing molecules are promising candidates to fabricate hetero-junction atomic layer epitaxy SiGe devices. However, thermal processes to dissociate unwanted ligands from parent molecules after dosing are not suitable for low thermal budget fabrication processes. Preliminary results of the electron radiation induced dissociation and/or desorption of diethylsilane (DES) covered Si (100) surfaces are reported. DES molecules were dosed onto Si surfaces at 120 K and the thermally desorbed species with and without 600 eV electron radiation were investigated by temperature programmed desorption (TPD). Electron beam dissociation effects as well as electron induced state changes reflected in TPD spectra will be discussed for several different initial gas exposures at 120 K. * Corresponding author

  11. Multi-Decadal Variations of Atmospheric Aerosols and Their Effects on Surface Radiation Trends

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Wild, Martin; Qian, Yun; Yu, Hongbin; Streets, David; Bian, Huisheng; Wang, Weiguo

    2010-01-01

    We present an investigation on multi-decadal changes of atmospheric aerosols and their effects on surface radiation using a global chemistry transport model along with the near-term to long-term data records. We focus on a 28-year time period of satellite era from 1980 to 2007, during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. We analyze the long-term global and regional aerosol trends and their relationship to the changes of aerosol and precursor emissions and assess the role aerosols play in the multi-decadal change of solar radiation reaching the surface (known as "dimming" or "brightening") at different regions of the world.

  12. Ultraviolet radiation climatology of the Earth`s surface and lower atmosphere. Final report

    SciTech Connect

    Madronich, S.; Stamnes, K.

    1999-03-01

    Ultraviolet (UV) radiation is the driving force of tropospheric chemistry and is furthermore detrimental to most living tissues. A three year modeling program was carried out to characterize the UV radiation in the lower atmosphere, with the objective of development a climatology of UV biologically active radiation, and of photo-dissociation reaction rates that are key to tropospheric chemistry. A comprehensive model, the Tropospheric Ultraviolet-Visible (TUV) model, was developed and made available to the scientific community. The model incorporates updated spectroscopic data, recent advances in radiative transfer theory, and allows flexible customization for the needs of different users. The TUV model has been used in conjunction with satellite-derived measurements of total atmospheric ozone and cloud amount, to develop a global climatology of UV radiation reaching the surface of the Earth. Initial validation studies are highly encouraging, showing that model predictions agree with direct measurements to ca. 5--10% at times when environmental conditions are well known, and to 10--30% for monthly averages when local environmental conditions can only be estimated remotely from satellite-based measurements. Additional validation studies are continuing.

  13. Image Formation by Incoherent and Coherent Transition Radiation from Flat and Rough Surfaces

    SciTech Connect

    Stupakov, Gennady; /SLAC

    2012-03-01

    In this paper we derive equations for the image formation of transverse profile of a relativistic beam obtained by means of optical transition radiation (OTR) from flat and rough metal surfaces. The motivation behind this study lies in the desire to suppress coherent transition radiation (COTR) observed in experiments at modern free electron lasers. The physical mechanism behind the problem of COTR is that the OTR is predominantly radiated at small angles of order of 1/{gamma} where {gamma} is the relativistic factor of the beam. This means that the transverse formation size of the image is of order of {bar {lambda}}{gamma} where {bar {lambda}} = {lambda}/2{pi} with {lambda} the radiation wavelength. For relativistic beams this can be comparable or even exceed the transverse size of the beam, which would mean that the image of the beam has very little to do with its transverse profile. It is fortuitous, however, that the incoherent image is formed by adding radiation energy of electrons and results in the transverse formation size being of order of {bar {lambda}}/{theta}{sub a}, with {theta}{sub a} is the aperture angle of the optical system. The COTR image, in contrast, is formed by adding electromagnetic field of electrons, and leads to the formation size {bar {lambda}}{gamma}. In situations when the COTR intensity exceeds that of OTR the COTR imaging makes the diagnostic incapable of measuring the beam profile.

  14. Tropical Trends in Surface Radiation Budgets in the Context of Global Trends

    NASA Astrophysics Data System (ADS)

    Pinker, Rachel T.; Zhang, Banglin; Ma, Yingtao

    2016-04-01

    For assessment of variability and trends in the Earth Radiation Balance, information is needed at climatic time scales. Satellite observations have been instrumental for advancing the understanding of radiative balance at global scale, however, the length of available satellite records is limited due to the frequent changes in the observing systems. In this paper we report on an effort to synthesize satellite observations from independent sources to estimates shortwave and longwave surface radiative fluxes at climatic time scales and use them to learn about their variability and trends with a focus on the tropics. From a comparison with similar global trends an attempt will be made to learn about possible causes of what is observed. The radiative fluxes were derived in the framework of the MEaSURES and NEWS programs; they are evaluated against ground observations and compared to independent satellite and model estimates. Attention is given to updates of knowledge on the radiative balance as compared to what is known from shorter time records.

  15. BOREAS RSS-14 Level -3 Gridded Radiometer and Satellite Surface Radiation Images

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Hodges, Gary; Smith, Eric A.

    2000-01-01

    The BOREAS RSS-14 team collected and processed GOES-7 and -8 images of the BOREAS region as part of its effort to characterize the incoming, reflected, and emitted radiation at regional scales. This data set contains surface radiation parameters, such as net radiation and net solar radiation, that have been interpolated from GOES-7 images and AMS data onto the standard BOREAS mapping grid at a resolution of 5 km N-S and E-W. While some parameters are taken directly from the AMS data set, others have been corrected according to calibrations carried out during IFC-2 in 1994. The corrected values as well as the uncorrected values are included. For example, two values of net radiation are provided: an uncorrected value (Rn), and a value that has been corrected according to the calibrations (Rn-COR). The data are provided in binary image format data files. Some of the data files on the BOREAS CD-ROMs have been compressed using the Gzip program. See section 8.2 for details. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  16. Mixed Convection with Conduction and Surface Radiation from a Vertical Channel with Discrete Heating

    NASA Astrophysics Data System (ADS)

    Londhe, S. D.; Rao, C. G.

    2013-10-01

    A numerical investigation into fluid flow and heat transfer for the geometry of a vertical parallel plate channel subjected to conjugate mixed convection with radiation is attempted here. The channel considered has three identical flush-mounted discrete heat sources in its left wall, while the right wall that does not contain any heat source acts as a sink. Air, assumed to be a radiatively non-participating and having constant thermophysical properties subject to the Boussinesq approximation, is the cooling agent. The heat generated in the left wall gets conducted along it and is later dissipated by mixed convection and radiation. The governing equations, considered in their full strength sans the boundary layer approximations, are converted into vorticity-stream function form and are then normalized. These equations along with pertinent boundary conditions are solved through finite volume method coupled with Gauss-Seidel iterative technique. The effects of modified Richardson number, surface emissivity, thermal conductivity and aspect ratio on local temperature distribution along the channel, maximum channel temperature and relative contributions of mixed convection and radiation have been thoroughly studied. The prominence of radiation in the present problem has been highlighted.

  17. Mapping the downwelling atmospheric radiation at the Earth's surface: A research strategy

    NASA Technical Reports Server (NTRS)

    Raschke, E.

    1986-01-01

    A strategy is presented along with background material for determining downward atmospheric radiation at the Earth's surface on a regional scale but over the entire globe, using available information on the temperature and humidity of the air near the ground and at cloud base altitudes. Most of these parameters can be inferred from satellite radiance measurements. Careful validation of the derived radiances will be required using ground-based direct measurements of radiances, to avoid systematic biases of these derived field quantities.

  18. Nano-cones Formed on a Surface of Semiconductors by Laser Radiation: Technology, Model and Properties

    NASA Astrophysics Data System (ADS)

    Medvid', A.; Onufrijevs, P.

    2011-12-01

    The new laser method for nanostructures formation on a surface of semiconductors Si, Ge, GaAs and SiGe, CdZnTe solid solutions is proposed. For the first time was shown the possibility of graded band gap structure formation in elementary semiconductors. Thermogradient effect has a main role in initial stage of nano-cones and graded band gap structure formation by laser radiation in semiconductors.

  19. Radiation measurement above the lunar surface by Kaguya gamma-ray spectrometer

    NASA Astrophysics Data System (ADS)

    Hasebe, Nobuyuki; Nagaoka, Hiroshi; Kusano, Hiroki; Hareyama, Matoko; Ideguchi, Yusuke; Shimizu, Sota; Shibamura, Eido

    The lunar surface is filled with various ionizing radiations such as high energy galactic particles, albedo particles and secondary radiations of neutrons, gamma rays and other elementary particles. A high-resolution Kaguya Gamma-Ray Spectrometer (KGRS) was carried on the Japan’s lunar explorer SELENE (Kaguya), the largest lunar orbiter since the Apollo missions. The KGRS instrument employed, for the first time in lunar exploration, a high-purity Ge crystal to increase the identification capability of elemental gamma-ray lines. The Ge detector is surrounded by BGO and plastic counters as for anticoincidence shields. The KGRS measured gamma rays in the energy range from 200 keV to 13 MeV with high precision to determine the chemical composition of the lunar surface. It provided data on the abundance of major elements over the entire lunar surface. In addition to the gamma-ray observation by the KGRS, it successfully measured the global distribution of fast neutrons. In the energy spectra of gamma-rays observed by the KGRS, several saw-tooth- peaks of Ge are included, which are formed by the collision interaction of lunar fast neutrons with Ge atoms in the Ge crystal. With these saw-tooth-peaks analysis, global distribution of neutrons emitted from the lunara surface was successfully created, which was compared with the previous results obtained by Lunar Prospector neutron maps. Another anticoincidence counter, the plastic counter with 5 mm thickness, was used to veto radiation events mostly generated by charged particles. A single photomultiplier serves to count scintillation light from the plastic scintillation counter. The global map of counting rates observed by the plastic counter was also created, implying that the radiation counting rate implies the geological distribution, in spite that the plastic counter mostly measures high energy charged particles and energetic neutrons. These results are presented and discussed.

  20. RADIATION ACCESS ZONE AND VENTILATION CONFINEMENT ZONE CRITERIA FOR THE MGR SURFACE FACILITIES

    SciTech Connect

    D. A. Padula

    2000-09-13

    The objectives of this technical report are to: (1) Establish the criteria for Radiation Access Zone (RAZ) designation. (2) Establish the criteria for the Ventilation Confinement Zone (VCZ) designation. The scope will be to formulate the RAZ and VCZ zoning designation for the Monitored Geologic Repository (MGR) surface facilities and to apply the zoning designations to the current Waste Handling Building (WHB), Waste Treatment Building (WTB), and Carrier Preparation Building (CPB) configurations.

  1. Radiation exposure to the orbiting lunar station and lunar surface related to reusable nuclear shuttle operations

    NASA Technical Reports Server (NTRS)

    Hutchinson, P. I.

    1972-01-01

    The radiation environment created by the Reusable Nuclear Vehicle (RNS) in performing its normal mission functions while in the lunar vicinity and the impact of that environment on the Orbiting Lunar Station (OLS) and/or the lunar surface are examined. Lunar surface exposures from the operating reactor were evaluated for both the arrival and departure burns and while there is little probability that manned bases would lie along the paths in which measurable exposures would be recorded, the analyses do indicate the need to consider this possibility in planning such operations. Conclusions supported by the analyses and recommended operational constraints for the RNS are presented.

  2. The Radiation Environment on the Martian Surface and during MSL's Cruise to Mars

    NASA Astrophysics Data System (ADS)

    Hassler, D. M.; Zeitlin, C.; Wimmer-Schweingruber, R. F.

    2012-12-01

    An important part of assessing present and past habitability of Mars is to understand and characterize "life limiting factors" on the surface, such as the radiation environment. Radiation exposure is also a major concern for future human missions and characterizing the radiation environment, both on the surface of Mars and inside the spacecraft during the cruise to Mars, provides critical information to aid in the planning for future human exploration of Mars. RAD was the first MSL instrument to start collecting data, beginning its science investigation during cruise (10 days after launch) and making the first ever measurements of the radiation environment on another planet. RAD is an energetic particle analyzer designed to characterize a broad spectrum of energetic particle radiation including galactic cosmic rays, solar energetic particles, and secondary neutrons created both in the Mars atmosphere and regolith. RAD observations consist of a time series of periodic (typically hourly) measurements of charged particles from protons (Z=1) up to iron (Z=26) for energies above >10 MeV/nucleon, as well as neutrons from 10 to ~ 100 MeV. These synoptic observations are designed to characterize both the short term variability associated with the onset of solar energetic particle events as well as the long term variability of galactic cosmic rays over the solar cycle. RAD measurements will also be used to quantify the flux of biologically hazardous radiation at the surface of Mars today, and determine how these fluxes vary on diurnal, seasonal, solar cycle and episodic (flare, storm) timescales. These measurements will allow calculations of the depth in rock or soil to which this flux, when integrated over long timescales, provides a lethal dose for known terrestrial organisms. Through such measurements, we can learn how deep below the surface life would have to be, or have been in the past, to be protected. This talk will discuss the results obtained during the ~7 months

  3. The Radiation Environment on the Martian Surface and during MSL's Cruise to Mars

    NASA Astrophysics Data System (ADS)

    Hassler, Donald M.; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; Ehresmann, Bent; Rafkin, Scot; Martin, Cesar; Boettcher, Stephan; Koehler, Jan; Guo, Jingnan; Brinza, David E.; Reitz, Guenther; Posner, Arik; the MSL Science Team

    2013-04-01

    An important part of assessing present and past habitability of Mars is to understand and characterize "life limiting factors" on the surface, such as the radiation environment. Radiation exposure is also a major concern for future human missions and characterizing the radiation environment, both on the surface of Mars and inside the spacecraft during the cruise to Mars, provides critical information to aid in the planning for future human exploration of Mars. RAD was the first MSL instrument to start collecting data, beginning its science investigation during cruise (10 days after launch) and making the first ever measurements of the radiation environment on another planet. RAD is an energetic particle analyzer designed to characterize a broad spectrum of energetic particle radiation including galactic cosmic rays, solar energetic particles, and secondary neutrons created both in the Mars atmosphere and regolith. RAD observations consist of a time series of periodic (typically hourly) measurements of charged particles from protons (Z=1) up to iron (Z=26) for energies above >10 MeV/nucleon, as well as neutrons from 10 to ~ 100 MeV. These synoptic observations are designed to characterize both the short term variability associated with the onset of solar energetic particle events as well as the long term variability of galactic cosmic rays over the solar cycle. RAD measurements will also be used to quantify the flux of biologically hazardous radiation at the surface of Mars today, and determine how these fluxes vary on diurnal, seasonal, solar cycle and episodic (flare, storm) timescales. These measurements will allow calculations of the depth in rock or soil to which this flux, when integrated over long timescales, provides a lethal dose for known terrestrial organisms. Through such measurements, we can learn how deep below the surface life would have to be, or have been in the past, to be protected. This talk will discuss the results obtained during the ~7 months

  4. Polarized radiance fields under a dynamic ocean surface: a three-dimensional radiative transfer solution

    SciTech Connect

    You Yu; Zhai Pengwang; Kattawar, George W.; Yang Ping

    2009-06-01

    The hybrid matrix operator, Monte Carlo (HMOMC) method previously reported [Appl. Opt.47, 1063-1071 (2008)APOPAI0003-693510.1364/AO.47.001063] is improved by neglecting higher-order terms in the coupling of the matrix operators and by introducing a dual grid scheme. The computational efficiency for solving the vector radiative transfer equation in a full 3D coupled atmosphere-surface-ocean system is substantially improved, and, thus, large-scale simulations of the radiance distribution become feasible. The improved method is applied to the computation of the polarized radiance field under realistic surface waves simulated by the power spectral density method. To the authors' best knowledge, this is the first time that the polarized radiance field under a dynamic ocean surface and the underwater image of an object above such an ocean surface have been reported.

  5. Effect of spine-like surface structures on the radiative properties of microorganism

    NASA Astrophysics Data System (ADS)

    Dong, J.; Zhao, J. M.; Liu, L. H.

    2016-04-01

    Many species of microorganisms possess spine-like surface structures. In this paper, we built a sphere with surface spines (SSS) model to represent such featured particles. The volume fraction of surface spines varied from 0% to 22% and the effects of the relative length, number, and radius of the spines on the radiation characteristics were studied using the discrete dipole approximation method with a complex relative refractive index of m=1.05+0.005i. Meanwhile, the approximations by the equivalent volume sphere (EVS) and the core shell sphere (CSS) models were examined. Surface spines led to increased scattering and absorption cross sections and asymmetry parameter. The EVS model overestimated the scattering cross section and underestimated the asymmetry parameter of SSS, the relative errors of which can exceed 10%, but EVS predicted the absorption cross section well. The CSS model combined with the Maxwell-Garnett mixing rule predicted the integral radiation parameters with relative errors less than 5% in all the cases, which was also valid for relative refractive indices with an imaginary part up to 0.1 and a real part up to 1.2. The resonance peaks of the phase function and Mueller matrix elements in the back scattering directions were damped out due to the existence of surface spines for size parameters larger than 10, which could not be captured by either the EVS or the CSS models.

  6. Interannual Variability in Radiative Cloud Effects and Cloud Macrophysical Properties From Surface Measurements

    NASA Astrophysics Data System (ADS)

    Long, C. N.; Ackerman, T. P.; Gaustad, K. L.; Turner, D. D.; Barnard, J. C.

    2005-12-01

    Recently significant progress has been made in inferring cloud effects and cloud macrophysical properties using surface measurements of broadband irradiance and basic meteorological variables. These "Flux Analysis" methodologies build on the original work by Long and Ackerman (2000), who show that these techniques include a high degree of repeatability since both the clear-sky and all-sky values include the same measuring instrument characteristics. Thus the resultant all-sky/clear-sky ratios and differences, while not reflecting improvement in the absolute accuracy inherent in the measurements, do lend themselves well to trend analyses. We will present results of the Flux Analysis methodology applied to measurements from various ARM and BSRN sites spanning the years of available data. These results include analyses of shortwave (SW) and longwave (LW) all-sky and clear-sky climatology; SW, LW, and net cloud effects; total (daylight) and LW effective (24 hour) fractional sky cover; cloud visible optical thickness; and estimates of cloud field effective radiating temperature and radiating surface height. Preliminary results of the upwelling components of clear-sky and cloud effect will also be presented, and used to infer the total net surface radiative cloud forcing.

  7. Initiation techniques and the vacuum-ultraviolet-radiation efficiency of a stabilized multichannel surface discharge

    NASA Astrophysics Data System (ADS)

    Tcheremiskine, V. I.; Uteza, O. P.; Sentis, M. L.; Mikheev, L. D.

    2006-01-01

    Multichannel surface discharges possess a number of advantageous characteristics for the optical pumping of photochemically driven lasers. This work reports on a type of large-area low-inductance sources of intense UV-VUV (vacuum-ultraviolet) radiation based on spatially stabilized multichannel discharges in gases. The discharges consist of several dozens of closely located parallel plasma channels initiated synchronously along a dielectric surface on the area of several hundred square centimeters. In comparison with a large-area diffuse surface discharge, the plasma confinement within relatively thin channels greatly improves the efficiency of the discharge emission in the VUV spectral range. Several techniques are introduced, which allow a synchronous formation and homogeneous development of multiple spatially stabilized discharge channels. Technical efficiency of the discharge radiation within the spectral range of 120-200nm reaches 5% and an effective brightness temperature of the radiating plasma exceeds 20kK. Synchronous operation of a number of multichannel discharge modules producing high-intensity submicrosecond optical pulses is demonstrated, which is of importance for the pump source scaling and geometrical adaptation.

  8. Effects of sulfate aerosol on the central Pennsylvania surface shortwave radiation budget. Master's thesis

    SciTech Connect

    Guimond, P.W.

    1994-12-01

    Surface radiation measurements are taken simultaneously with measurements of meteorological variables including temperature, pressure, relative humidity, and visibility to evaluate the impact of sulfate haze on the surface radiation budget. A relationship is sought between flux losses due only to aerosol and relative humidity, visibility or both, with the goal of facilitating parameterization of sulfate hazes by climate modelers. At the same time, a rotating shadowband radiometer (RSR) is compared with a more costly sun photometer to determine the feasibility of substituting the former for the latter in future research. It is found that depletion of surface radiation due to aerosol is typically ten to twenty percent of initial insolation, and that the losses can be correlated with zenith angle, relative humidity and optical depth. In the case of flux loss as a function of optical depth, the two are related in a nearly linear fashion. It is also discovered that the RSR has a predictable error owing to a wider field of view than the sun photometer, and can be used as a replacement for the former by correcting for the error.

  9. A Retrospective, Iterative, Geometry-Based (RIGB) tilt-correction method for radiation observed by automatic weather stations on snow-covered surfaces: application to Greenland

    NASA Astrophysics Data System (ADS)

    Wang, Wenshan; Zender, Charles S.; van As, Dirk; Smeets, Paul C. J. P.; van den Broeke, Michiel R.

    2016-03-01

    Surface melt and mass loss of the Greenland Ice Sheet may play crucial roles in global climate change due to their positive feedbacks and large fresh-water storage. With few other regular meteorological observations available in this extreme environment, measurements from automatic weather stations (AWS) are the primary data source for studying surface energy budgets, and for validating satellite observations and model simulations. Station tilt, due to irregular surface melt, compaction and glacier dynamics, causes considerable biases in the AWS shortwave radiation measurements. In this study, we identify tilt-induced biases in the climatology of surface shortwave radiative flux and albedo, and retrospectively correct these by iterative application of solar geometric principles. We found, over all the AWS from the Greenland Climate Network (GC-Net), the Kangerlussuaq transect (K-transect) and the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) networks, insolation on fewer than 40 % of clear days peaks within ±0.5 h of solar noon time, with the largest shift exceeding 3 h due to tilt. Hourly absolute biases in the magnitude of surface insolation can reach up to 200 W m-2, with respect to the well-understood clear-day insolation. We estimate the tilt angles and their directions based on the solar geometric relationship between the simulated insolation at a horizontal surface and the observed insolation by these tilted AWS under clear-sky conditions. Our adjustment reduces the root mean square error (RMSE) against references from both satellite observation and reanalysis by 16 W m-2 (24 %), and raises the correlation coefficients with them to above 0.95. Averaged over the whole Greenland Ice Sheet in the melt season, the adjustment in insolation to compensate station tilt is ˜ 11 W m-2, enough to melt 0.24 m of snow water equivalent. The adjusted diurnal cycles of albedo are smoother, with consistent semi-smiling patterns. The seasonal

  10. Interpretation of Impact Features on the Surface of the WFPC-2 Radiator

    NASA Technical Reports Server (NTRS)

    Anz-Meador, P. D.; Christiansen, Eric L.; Kou, J.-C.

    2011-01-01

    An examination of the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC-2) radiator assembly was conducted at NASA Goddard Space Flight Center (GSFC) during the summer of 2009. Immediately apparent was the predominance of impact features resident only in the thermal paint layer; similar phenomenology was observed during a prior survey of the WFPC-1 radiator. As well, larger impact features displayed spallation zones, darkened areas, and other features not encountered in impacts onto bare surfaces. Whereas the characterization of impact features by depth and diameter on unpainted surfaces has been long established, the mitigation provided by the painted layer presented a challenge to further analysis of the WFPC-2 features; a literature search revealed no systematic characterization of the ballistic limit equations of painted or coated surfaces. In order to characterize the impactors responsible for the observed damage, an understanding of the cratering and spallation phenomenology of the painted surface was required. To address that challenge, NASA sponsored a series of hypervelocity calibration shots at the White Sands Test Facility (WSTF). This effort required the following activities: the production, painting, and artificial ageing of test coupons in a manner similar to the actual radiator; the determination of the test matrix parameters projectile diameter and material (mass density), impact velocity, and impact angle, so as to enable both an adequate characterization of the impact by projectile and impact geometry and support hydrocode modeling to fill in and extend the applicability of the calibration shots; the selection of suitable projectiles; logistics; and an analysis of feature characteristics upon return of the coupons. This paper reports the results of the test campaign and presents ballistic limit equations for painted surfaces. We also present initial results of our interpretation methodologies.

  11. An ultraviolet simulator for the incident Martian surface radiation and its applications

    NASA Astrophysics Data System (ADS)

    Kolb, C.; Abart, R.; Bérces, A.; Garry, J. R. C.; Hansen, A. A.; Hohenau, W.; Kargl, G.; Lammer, H.; Patel, M. R.; Rettberg, P.; Stan-Lotter, H.

    2005-10-01

    Ultraviolet (UV) radiation can act on putative organic/biological matter at the Martian surface in several ways. Only absorbed, but not transmitted or reflected, radiation energy can be photo-chemically effective. The most important biological UV effects are due to photochemical reactions in nucleic acids, DNA or RNA, which constitute the genetic material of all cellular organisms and viruses. Protein or lipid effects generally play a minor role, but they are also relevant in some cases. UV radiation can induce wavelengths-specific types of DNA damage. At the same time it can also induce the photo-reversion reaction of a UV induced DNA photoproduct of nucleic acid bases, the pyrimidine dimers. Intense UVB and UVC radiation, experienced on early Earth and present-day Mars, has been revealed to be harmful to all organisms, including extremophile bacteria and spores. Moreover, the formation of oxidants, catalytically produced in the Martian environment through UV irradiation, may be responsible for the destruction of organic matter on Mars. Following this, more laboratory simulations are vital in order to investigate and understand UV effects on organic matter in the case of Mars. We have designed a radiation apparatus that simulates the anticipated Martian UV surface spectrum between 200 and 400 nm (UVC UVA). The system comprises a UV enhanced xenon arc lamp, special filter-sets and mirrors to simulate the effects of the Martian atmospheric column and dust loading. We describe the technical setup and performance of the system and discuss its uses for different applications. The design is focused on portability, therefore, the Mars-UV simulator represents a device for several different Mars simulation facilities with specific emphasis on Mars research topics.

  12. Features and causes of recent surface solar radiation dimming and brightening patterns

    NASA Astrophysics Data System (ADS)

    Hatzianastassiou, N.; Papadimas, C. D.; Matsoukas, C.; Pavlakis, K.; Fotiadi, A.; Wild, M.; Vardavas, I.

    2012-04-01

    Incoming solar radiation at the Earth's surface has undergone substantial decreases/increases on decadal timescales in the second half of 20th century. More specifically, surface measurements have indicated a widespread decrease of surface solar radiation (SSR) from the 1950s to the 1980s, described as global dimming, followed by a period with either no more decrease or even an increase at various locations worldwide till the end of 1990s, namely a global brightening. These measured patterns of SSR are, in general, in line with SSR fluxes computed with radiative transfer models (RTMs) using satellite input data, while efforts are currently being made to reproduce them with regional or global climate models. The advantage of reproducing SSR dimming/brightening with RTMs is that an almost complete coverage of the globe is possible, whereas dimming/brightening patterns are obtained under both clear- and all-sky conditions. Moreover, an even more important and incomparable advantage of the use of RTMs for reproducing SSR dimming/brightening, is that it makes possible the identification of their causes in terms of specific radiative forcing agents, and the assessment and quantification of their relative contribution to GDB, which is of major importance for understanding current and future climate changes. In the present study, first an update of SSR dimming/brightening at global scale beyond 2000 is attempted using a spectral RTM along with a variety of satellite and reanalyses input data. The results are obtained at scales varying from the regional to continental/hemispherical/global, and are validated through comparisons against quality surface measurements from reference global networks such as GEBA (Global Energy Balance Archive) and BSRN (Baseline Surface Radiation Network). An inter-hemispherical difference is revealed up to 2007, consisting in a clear dimming in the South Hemisphere (SH), against a no clear dimming/brightening signal in North Hemisphere (NH

  13. Effect of Spectrally Varying Albedo of Vegetation Surfaces on Shortwave Radiation Fluxes and Aerosol Direct Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Zhu, L.; Martins, J. V.; Yu, H.

    2012-01-01

    This study develops an algorithm for representing detailed spectral features of vegetation albedo based on Moderate Resolution Imaging Spectrometer (MODIS) observations at 7 discrete channels, referred to as the MODIS Enhanced Vegetation Albedo (MEVA) algorithm. The MEVA algorithm empirically fills spectral gaps around the vegetation red edge near 0.7 micrometers and vegetation water absorption features at 1.48 and 1.92 micrometers which cannot be adequately captured by the MODIS 7 channels. We then assess the effects of applying MEVA in comparison to four other traditional approaches to calculate solar fluxes and aerosol direct radiative forcing (DRF) at the top of atmosphere (TOA) based on the MODIS discrete reflectance bands. By comparing the DRF results obtained through the MEVA method with the results obtained through the other four traditional approaches, we show that filling the spectral gap of the MODIS measurements around 0.7 micrometers based on the general spectral behavior of healthy green vegetation leads to significant improvement in the instantaneous aerosol DRF at TOA (up to 3.02Wm(exp -2) difference or 48% fraction of the aerosol DRF, .6.28Wm(exp -2), calculated for high spectral resolution surface reflectance from 0.3 to 2.5 micrometers for deciduous vegetation surface). The corrections of the spectral gaps in the vegetation spectrum in the near infrared, again missed by the MODIS reflectances, also contributes to improving TOA DRF calculations but to a much lower extent (less than 0.27Wm(exp -2), or about 4% of the instantaneous DRF). Compared to traditional approaches, MEVA also improves the accuracy of the outgoing solar flux between 0.3 to 2.5 micrometers at TOA by over 60Wm(exp -2) (for aspen 3 surface) and aerosol DRF by over 10Wm(exp -2) (for dry grass). Specifically, for Amazon vegetation types, MEVA can improve the accuracy of daily averaged aerosol radiative forcing in the spectral range of 0.3 to 2.5 micrometers at equator at the

  14. Effect of Increasing Doses of γ-Radiation on Bone Marrow Stromal Cells Grown on Smooth and Rough Titanium Surfaces

    PubMed Central

    Huang, Bo; Guang, Mengkai; Ye, Jun; Gong, Ping; Tang, Hua

    2015-01-01

    Radiation therapy for oral and maxillofacial tumors could damage bone marrow stromal cells (BMSCs) in jaw, which caused dental implant failure. However, how radiation affects BMSCs on SLA (sandblasted with large-grits, acid-etched) surfaces is still unknown. The aim of this study was to investigate effect of different dose of γ-radiation on BMSCs on SLA and PT (polished titanium) surfaces. Rat BMSCs were radiated with 2, 4, and 8 Gy γ-radiation and then seeded on both surfaces. Cell adhesion, spreading, and proliferation were tested. The osteogenesis and the adipogenesis ability were examined by Alizarin-Red and Oil-Red staining, respectively. Real-time PCR was performed to detect osteogenic (osteocalcin, OCN; runt-related transcription factor 2, Runx2) and adipogenic (peroxisome proliferator-activated receptor gamma, PPARγ) gene expression at days 7 and 14 postirradiation. Results showed that γ-radiation reduced cell proliferation, adhesion, spreading, and osteogenic differentiation. 2 Gy radiation promoted adipogenic differentiation, but it was significantly decreased when dosage reached 4 Gy. In conclusion, results suggest that γ-radiation influenced BMSCs behaviors in a dosage-dependent manner except adipogenic differentiation, low dose promoted it, and high dose inhibited it. This effect was influenced by surface characteristics, which may explain the different failure rate of various implants in patients after radiation. PMID:26257788

  15. Status of the Development of Low Cost Radiator for Surface Fission Power - II

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Maxwell, Taylor; Anderson, William G.; Wagner, Corey; Wrosch, Matthew; Briggs, Maxwell H.

    2016-01-01

    NASA Glenn Research Center (GRC) is developing fission power system technology for future Lunar and Martian surface power applications. The systems are envisioned in the 10 to 100kWe range and have an anticipated design life of 8 to 15 years with no maintenance. NASA GRC is currently setting up a 55 kWe non-nuclear system ground test in thermal-vacuum to validate technologies required to transfer reactor heat, convert the heat into electricity, reject waste heat, process the electrical output, and demonstrate overall system performance. The paper reports on the development of the heat pipe radiator to reject the waste heat from the Stirling convertors. Reducing the radiator mass, size, and cost is essential to the success of the program. To meet these goals, Advanced Cooling Technologies, Inc. (ACT) and Vanguard Space Technologies, Inc. (VST) are developing a single facesheet radiator with heat pipes directly bonded to the facesheet. The facesheet material is a graphite fiber reinforced composite (GFRC) and the heat pipes are titanium/water Variable Conductance Heat Pipes (VCHPs). By directly bonding a single facesheet to the heat pipes, several heavy and expensive components can be eliminated from the traditional radiator design such as, POCO"TM" foam saddles, aluminum honeycomb, and a second facesheet. As mentioned in previous papers by the authors, the final design of the waste heat radiator is described as being modular with independent GFRC panels for each heat pipe. The present paper reports on test results for a single radiator module as well as a radiator cluster consisting of eight integral modules. These tests were carried out in both ambient and vacuum conditions. While the vacuum testing of the single radiator module was performed in the ACT's vacuum chamber, the vacuum testing of the eight heat pipe radiator cluster took place in NASA GRC's vacuum chamber to accommodate the larger size of the cluster. The results for both articles show good agreement

  16. Clouds, radiation, and the diurnal cycle of sea surface temperature in the tropical Western Pacific

    SciTech Connect

    Webster, P.J.; Clayson, C.A.; Curry, J.A.

    1996-04-01

    In the tropical Western Pacific (TWP) Ocean, the clouds and the cloud-radiation feedback can only be understood in the context of air/sea interactions and the ocean mixed layer. Considerable interest has been shown in attempting to explain why sea surface temperature (SST) rarely rises above 30{degrees}C, and gradients of the SST. For the most part, observational studies that address this issue have been conducted using monthly cloud and SST data, and the focus has been on intraseasonal and interannual time scales. For the unstable tropical atmosphere, using monthly averaged data misses a key feedback between clouds and SST that occurs on the cloud-SST coupling time scale, which was estimated to be 3-6 days for the unstable tropical atmosphere. This time scale is the time needed for a change in cloud properties, due to the change of ocean surface evaporation caused by SST variation, to feed back to the SST variation, to feed back to the SST through its effect on the surface heat flux. This paper addresses the relationship between clouds, surface radiation flux and SST of the TWP ocean over the diurnal cycle.

  17. A radiosity-based model to compute the radiation transfer of soil surface

    NASA Astrophysics Data System (ADS)

    Zhao, Feng; Li, Yuguang

    2011-11-01

    A good understanding of interactions of electromagnetic radiation with soil surface is important for a further improvement of remote sensing methods. In this paper, a radiosity-based analytical model for soil Directional Reflectance Factor's (DRF) distributions was developed and evaluated. The model was specifically dedicated to the study of radiation transfer for the soil surface under tillage practices. The soil was abstracted as two dimensional U-shaped or V-shaped geometric structures with periodic macroscopic variations. The roughness of the simulated surfaces was expressed as a ratio of the height to the width for the U and V-shaped structures. The assumption was made that the shadowing of soil surface, simulated by U or V-shaped grooves, has a greater influence on the soil reflectance distribution than the scattering properties of basic soil particles of silt and clay. Another assumption was that the soil is a perfectly diffuse reflector at a microscopic level, which is a prerequisite for the application of the radiosity method. This radiosity-based analytical model was evaluated by a forward Monte Carlo ray-tracing model under the same structural scenes and identical spectral parameters. The statistics of these two models' BRF fitting results for several soil structures under the same conditions showed the good agreements. By using the model, the physical mechanism of the soil bidirectional reflectance pattern was revealed.

  18. Local Adaptive Calibration of the GLASS Surface Incident Shortwave Radiation Product Using Smoothing Spline

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Liang, S.; Wang, G.

    2015-12-01

    Incident solar radiation (ISR) over the Earth's surface plays an important role in determining the Earth's climate and environment. Generally, can be obtained from direct measurements, remotely sensed data, or reanalysis and general circulation models (GCMs) data. Each type of product has advantages and limitations: the surface direct measurements provide accurate but sparse spatial coverage, whereas other global products may have large uncertainties. Ground measurements have been normally used for validation and occasionally calibration, but transforming their "true values" spatially to improve the satellite products is still a new and challenging topic. In this study, an improved thin-plate smoothing spline approach is presented to locally "calibrate" the Global LAnd Surface Satellite (GLASS) ISR product using the reconstructed ISR data from surface meteorological measurements. The influences of surface elevation on ISR estimation was also considered in the proposed method. The point-based surface reconstructed ISR was used as the response variable, and the GLASS ISR product and the surface elevation data at the corresponding locations as explanatory variables to train the thin plate spline model. We evaluated the performance of the approach using the cross-validation method at both daily and monthly time scales over China. We also evaluated estimated ISR based on the thin-plate spline method using independent ground measurements at 10 sites from the Coordinated Enhanced Observation Network (CEON). These validation results indicated that the thin plate smoothing spline method can be effectively used for calibrating satellite derived ISR products using ground measurements to achieve better accuracy.

  19. Seasonal variation of surface and atmospheric cloud radiative forcing over the globe derived from satellite data

    NASA Technical Reports Server (NTRS)

    Gupta, Shashi K.; Staylor, W. Frank; Darnell, Wayne L.; Wilber, Anne C.; Ritchey, Nancy A.

    1993-01-01

    Global distributions of surface and atmospheric cloud radiative forcing parameters have been derived using parameterized radiation models with satellite meteorological data from the International Satellite Cloud Climatology Project, and directly measured top-of-atmosphere radiative fluxes from the Earth Radiation Budget Experiment. Specifically, shortwave, longwave, and total cloud forcing at the surface, and column-averaged values of longwave cloud forcing of the atmosphere were derived for the midseasonal months of April, July, and October 1985 and January 1986, covering a complete annual cycle. Seasonal variability is illustrated by comparing the results for July 1985 and January 1986, which represent the seasonal extremes. Surface shortwave cloud forcing is always negative, representing a cooling of the surface, with strongest cooling (-120 to -180 W/sq m) occurring over midlatitude storm tracks of the summer hemisphere. Surface longwave cloud forcing is always positive, representing a warming of the surface, with strongest warming (60 to 75 W/sq m) occurring over storm tracks of the winter hemisphere. Zonal averages show the entire summer hemisphere dominated by shortwave cooling, the middle and high latitudes of the winter hemisphere dominated by longwave warming, and a broad zone of transition in between. The globally averaged total cloud forcing amounts to a cooling throughout the year, ranging from a low of about -12 W/sq m for July 1985 to a high of about -25 W/sq m for January 1986. The longwave cloud forcing of the atmosphere shows a strong warming over deep convective regions in the tropics and a moderate cooling outside the tropics, amounting to a weak cooling (-2 to -5 W/sq m) in the global average. Comparisons of the results with general circulation model simulations show broad qualitative agreement regarding the locations of prominent warming and cooling regions. Quantitative comparisons, on the other hand, show significant differences between the

  20. Analysis of solar radiation on the surface estimated from GWNU solar radiation model with temporal resolution of satellite cloud fraction

    NASA Astrophysics Data System (ADS)

    Zo, Il-Sung; Jee, Joon-Bum; Lee, Kyu-Tae; Kim, Bu-Yo

    2016-08-01

    Preliminary analysis with a solar radiation model is generally performed for photovoltaic power generation projects. Therefore, model accuracy is extremely important. The temporal and spatial resolutions used in previous studies of the Korean Peninsula were 1 km × 1 km and 1-h, respectively. However, calculating surface solar radiation at 1-h intervals does not ensure the accuracy of the geographical effects, and this parameter changes owing to atmospheric elements (clouds, aerosol, ozone, etc.). Thus, a change in temporal resolution is required. In this study, one-year (2013) analysis was conducted using Chollian geostationary meteorological satellite data from observations recorded at 15-min intervals. Observation data from the intensive solar site at Gangneung-Wonju National University (GWNU) showed that the coefficient of determination (R²), which was estimated for each month and season, increased, whereas the standard error (SE) decreased when estimated in 15-min intervals over those obtained in 1-h intervals in 2013. When compared with observational data from 22 solar sites of the Korean Meteorological Administration (KMA), R2 was 0.9 or higher on average, and over- or under-simulated sites did not exceed 3 sites. The model and 22 solar sites showed similar values of annual accumulated solar irradiation, and their annual mean was similar at 4,998 MJ m-2 (3.87 kWh m-2). These results show a difference of approximately ± 70 MJ m-2 (± 0.05 kWh m-2) from the distribution of the Korean Peninsula estimated in 1-h intervals and a higher correlation at higher temporal resolution.

  1. More Frequent Cloud Free Sky and Less Surface Solar Radiation in China from 1955-2000

    NASA Technical Reports Server (NTRS)

    Qian, Yun; Kaiser, Dale P.; Leung, L. Ruby; Xu, Ming

    2006-01-01

    In this study, we used newly available data frorn extended weather stations and time period to reveal that much of China has experienced significant decreases in cloud cover over the last half of the Twentieth century. This conclusion is supported by analysis of the more reliably observed frequency of cloud-free sky and overcast sky. We estimated that the total cloud cover and low cloud cover in China have decreased 0.88% and 0.33% per decade, respectively, and cloud-free days have increased 0.60% and overcast days decreased 0.78% per decade from 1954-2001. Meanwhile, both solar radiation and pan evaporation have decreased in China, with'solar radiation decreasing 3.1 w/square m and pan evaporation decreasing 39 mm per decade. Combining these results with findings of previous studies, we speculated that increased air pollution may have produced a fog-like haze that reflected/absorbed radiation from the sun and resulted in less solar radiation reaching the surface, despite concurrent increasing trends in cloud-free sky over China.

  2. Synergistic effects of ultraviolet radiation, thermal cycling and atomic oxygen on altered and coated Kapton surfaces

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Bruckner, Eric J.; Rodriguez, Elvin

    1992-01-01

    The photovoltaic (PV) power system for Space Station Freedom (SSF) uses solar array blankets which provide structural support for the solar cells and house the electrical interconnections. In the low earth orbital (LEO) environment where SSF will be located, surfaces will be exposed to potentially damaging environmental conditions including solar ultraviolet (UV) radiation, thermal cycling, and atomic oxygen. It is necessary to use ground based tests to determine how these environmental conditions would affect the mass loss and optical properties of candidate SSF blanket materials. Silicone containing, silicone coated, and SiO(x) coated polyimide film materials were exposed to simulated LEO environmental conditions to determine their durability and whether the environmental conditions of UV, thermal cycling and oxygen atoms act synergistically on these materials. A candidate PV blanket material called AOR Kapton, a polysiloxane polyimide cast from a solution mixture, shows an improvement in durability to oxygen atoms erosion after exposure to UV radiation or thermal cycling combined with UV radiation. This may indicate that the environmental conditions react synergistically with this material, and the damage predicted by exposure to atomic oxygen alone is more severe than that which would occur in LEO where atomic oxygen, thermal cycling and UV radiation are present together.

  3. Synergistic effects of ultraviolet radiation, thermal cycling, and atomic oxygen on altered and coated Kapton surfaces

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Bruckner, Eric J.; Rodriguez, Elvin

    1992-01-01

    The photovoltaic (PV) power system for Space Station Freedom (SSF) uses solar array blankets which provide structural support for the solar cells and house the electrical interconnections. In the low Earth orbital (LEO) environment where SSF will be located, surfaces will be exposed to potentially damaging environmental conditions including solar ultraviolet (UV) radiation, thermal cycling, and atomic oxygen. It is necessary to use ground based tests to determine how these environmental conditions would affect the mass loss and optical properties of candidate SSF blanket materials. Silicone containing, silicone coated, and SiO(x) coated polyimide film materials were exposed to simulated LEO environmental conditions to determine there durability and whether the environmental conditions of UV, thermal cycling and oxygen atoms act synergistically on these materials. A candidate PV blanket material called AOR Kapton, a polysiloxane polyimide cast from a solution mixture, shows an improvement in durability to oxygen atoms erosion after exposure to UV radiation or thermal cycling combined with UV radiation. This may indicate that the environmental conditions react synergistically with this material, and the damage predicted by exposure to atomic oxygen alone is more severe than that which would occur in LEO where atomic oxygen, thermal cycling and UV radiation are present together.

  4. Surface Radiation Survey at the Shepley’s Hill Remediation Site, Devens, Massachusettes

    SciTech Connect

    J. R. Giles; C. P. Oertel; L. G. Roybal

    2009-09-01

    The Idaho National Laboratory (INL) provided technical support for ongoing environmental remediation activities at the Shepley’s Hill remediation site, near Devens, MA. The technical support included the completion of a radiation survey of naturally occurring radioactive materials (NORM) at Shepley’s Hill, Shepley’s Hill landfill cover, and Red Cove areas. The objective of the radiation survey was to assess the ability of the INL backpack sodium iodide spectroscopy (BaSIS) system to detect elevated levels of NORM that may be associated with radon-222 emanation from near surface and subsurface fractures in the area. It is postulated that these fracture zones provide subsurface conduits for the transport of environmental contaminants. As such, location of these fracture sets will proved EPA Region 1 with the means for completing the development of an accurate site conceptual model. The results of the radiological survey show that some of the radiological anomalies correlate with currently mapped rock outcrops; however, not all of the rock outcrops in the surveyed area have been mapped. As such, it is not conclusive that all of the radiological anomalies correspond with surface rock outcrops. EPA Region 1 intends to perform a more comprehensive correlation of the radiation data collected with the BaSIS system with additional data sets such as detailed bedrock structural mapping, 2-dimensional resistivity profiling, and high-resolution topographic mapping. The results of this effort will be used in consideration of designing a potential follow-on effort for mapping of radon.

  5. Clear-Sky Surface Solar Radiation During South China Sea Monsoon Experiment

    NASA Technical Reports Server (NTRS)

    Lin, Po-Hsiung; Chou, Ming-Dah; Ji, Qiang; Tsay, Si-Chee; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Downward solar fluxes measured at Dungsha coral island (20 deg. 42 min. N, 116 deg. 43 min. E) during the South China Sea Monsoon Experiment (May-June 1998) have been calibrated and compared with radiative transfer calculations for three clear-sky days. Model calculations use water vapor and temperature profiles from radiosound measurements and the aerosol optical thickness derived from sunphotometric radiance measurements at the surface. Results show that the difference between observed and model-calculated downward fluxes is less than 3% of the daily mean. Averaged over the three clear days, the difference reduces to 1%. The downward surface solar flux averaged over the three days is 314 W per square meters from observations and 317 W per square meters from model calculations, This result is consistent with a previous study using TOGA CAORE measurements, which found good agreements between observations and model calculations. This study provides an extra piece of useful information on the modeling of radiative transfer, which fills in the puzzle of the absorption of solar radiation in the atmosphere.

  6. Experimental study of radiation power flux on the target surface during high heat plasma irradiation

    NASA Astrophysics Data System (ADS)

    Litunovsky, V. N.; Ovchinnikov, I. B.; Titov, V. A.

    2001-03-01

    Some new data of the experimental study of visible radiation from the plasma shielding layer (SL) on the target surface during high heat plasma-material interaction are given in the report. The experiments were performed on the VIKA facility. Long pulse ( τp=0.36 ms) high power ( Pirr˜100 GW m -2 plasma streams were used for irradiation of graphite and tungsten samples. The target inclination ( α=0° normal irradiation; 45°; 70°) and magnetic field ( B=0 to 3 T) were varied in experiments. It is shown that the values of ( Δλ≈400 to 700 nm) visible radiation power flux (VRPF) on the target