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Sample records for radiometry saber kinetic

  1. Errors in Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) Kinetic Temperature Caused by Non-Local Thermodynamic Equilibrium Model Parameters

    NASA Technical Reports Server (NTRS)

    Garcia-Comas, Maya; Lopez-Puertas, M.; Funke, B.; Bermejo-Pantaleon, D.; Marshall, Benjamin T.; Mertens, Christopher J.; Remsberg, Ellis E.; Mlynczak, Martin G.; Gordley, L. L.; Russell, James M.

    2008-01-01

    The vast set of near global and continuous atmospheric measurements made by the SABER instrument since 2002, including daytime and nighttime kinetic temperature (T(sub k)) from 20 to 105 km, is available to the scientific community. The temperature is retrieved from SABER measurements of the atmospheric 15 micron CO2 limb emission. This emission separates from local thermodynamic equilibrium (LTE) conditions in the rarefied mesosphere and thermosphere, making it necessary to consider the CO2 vibrational state non-LTE populations in the retrieval algorithm above 70 km. Those populations depend on kinetic parameters describing the rate at which energy exchange between atmospheric molecules take place, but some of these collisional rates are not well known. We consider current uncertainties in the rates of quenching of CO2 (v2 ) by N2 , O2 and O, and the CO2 (v2 ) vibrational-vibrational exchange to estimate their impact on SABER T(sub k) for different atmospheric conditions. The T(sub k) is more sensitive to the uncertainty in the latter two and their effects depend on altitude. The T(sub k) combined systematic error due to non-LTE kinetic parameters does not exceed +/- 1.5 K below 95 km and +/- 4-5 K at 100 km for most latitudes and seasons (except for polar summer) if the Tk profile does not have pronounced vertical structure. The error is +/- 3 K at 80 km, +/- 6 K at 84 km and +/- 18 K at 100 km under the less favourable polar summer conditions. For strong temperature inversion layers, the errors reach +/- 3 K at 82 km and +/- 8 K at 90 km. This particularly affects tide amplitude estimates, with errors of up to +/- 3 K.

  2. Sounding of the atmosphere using broadband emission radiometry (SABER): sensor design, performance, and lessons learned

    NASA Astrophysics Data System (ADS)

    Brown, Steven B.; Jensen, Mark; Jensen, Scott; Hansen, Glen; Zollinger, Lorin; Esplin, Roy; Miller, James B.

    2006-08-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, a 10-channel infrared (1.27 - 16.9 μm) radiometer, was launched on the TIMED (Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics) satellite in December 2001 from Vandenburg Air Force Base. SABER is being used to measure earthlimb emissions and to characterize infrared radiation, allowing calculation of cooling rates and determination of composition and temperature profiles in the mesosphere, lower thermosphere, and ionosphere (60-180 km). The SABER telescope is an on-axis Cassegrain design with a picket-fence tuning fork chopper at the first focus and a clamshell re-imager to focus the image on the focal plane. The telescope was designed to reject stray light from the Earth and atmosphere outside the instrument's instantaneous field-of-view (IFOV). The baffle assembly contains a single-axis scan mirror, which permits the 2 km vertical IFOV of each detector to be scanned from the Earth to a 400 km tangent height. The telescope and baffle assembly are cooled to 220 K by a dedicated radiator. The focal plane assembly is cooled to 75 K by a miniature cryogenic refrigerator. Field programmable gate arrays are used to implement state machine algorithms for control and operation of the instrument and subsystems. Although originally designed for a two-year lifetime requirement, the SABER instrument has been in continuous operation since January 2002. This paper discusses the SABER instrument design and innovations developed to achieve the required performance, along with instrument performance and lessons learned from the program.

  3. Kinetic Temperature and Carbon Dioxide from Broadband Infrared Limb Emission Measurements Taken from the TIMED/SABER Instrument

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Russell III, James M.; Mlynczak, Martin G.; She, Chiao-Yao; Schmidlin, Francis J.; Goldberg, Richard A.; Lopez-Puertas, Manuel; Wintersteiner, Peter P.; Picard, Richard H.; Winick, Jeremy R.; hide

    2008-01-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment is one of four instruments on NASA's Thermosphere-Ionosphere-Energetics and Dynamics (TIMED) satellite. SABER measures broadband infrared limb emission and derives vertical profiles of kinetic temperature (Tk) from the lower stratosphere to approximately 120 km, and vertical profiles of carbon dioxide (CO2) volume mixing ratio (vmr) from approximately 70 km to 120 km. In this paper we report on SABER Tk/CO2 data in the mesosphere and lower thermosphere (MLT) region from the version 1.06 dataset. The continuous SABER measurements provide an excellent dataset to understand the evolution and mechanisms responsible for the global two-level structure of the mesopause altitude. SABER MLT Tk comparisons with ground-based sodium lidar and rocket falling sphere Tk measurements are generally in good agreement. However, SABER CO2 data differs significantly from TIME-GCM model simulations. Indirect CO2 validation through SABER-lidar MLT Tk comparisons and SABER-radiation transfer comparisons of nighttime 4.3 micron limb emission suggest the SABER-derived CO2 data is a better representation of the true atmospheric MLT CO2 abundance compared to model simulations of CO2 vmr.

  4. Kinetic temperature and carbon dioxide from broadband infrared limb emission measurements taken from the TIMED/SABER instrument

    NASA Astrophysics Data System (ADS)

    Mertens, Christopher J.; Russell, James M., III; Mlynczak, Martin G.; She, Chiao-Yao; Schmidlin, Francis J.; Goldberg, Richard A.; López-Puertas, Manuel; Wintersteiner, Peter P.; Picard, Richard H.; Winick, Jeremy R.; Xu, Xiaojing

    2009-01-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment is one of four instruments on NASA’s Thermosphere Ionosphere Energetics and Dynamics (TIMED) satellite. SABER measures broadband infrared limb emission and derives vertical profiles of kinetic temperature (Tk) from the lower stratosphere to approximately 120 km, and vertical profiles of carbon dioxide (CO2) volume mixing ratio (vmr) from approximately 70 km to 120 km. In this paper we report on SABER Tk/CO2 data in the mesosphere and lower thermosphere (MLT) region from the version 1.06 dataset. The continuous SABER measurements provide an excellent dataset to understand the evolution and mechanisms responsible for the global two-level structure of the mesopause altitude. SABER MLT Tk comparisons with ground-based sodium lidar and rocket falling sphere Tk measurements are generally in good agreement. However, SABER CO2 data differs significantly from TIME-GCM model simulations. Indirect CO2 validation through SABER-lidar MLT Tk comparisons and SABER-radiation transfer comparisons of nighttime 4.3 μm limb emission suggest the SABER-derived CO2 data is a better representation of the true atmospheric MLT CO2 abundance compared to model simulations of CO2 vmr.

  5. Retrieval of Kinetic Temperature and Carbon Dioxide Abundance from Non-Local Thermodynamic Equilibrium Limb Emission Measurements made by the SABER Experiment on the TIMED Satellite

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Mlynczak, Martin G.; Lopez-Puertas, Manuel; Wintersteiner, Peter P.; Picard, Richard H.; Winick, Jeremy R.; Gordley, Larry L.; Russell, James M., III

    2002-01-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment was launched onboard the TIMED satellite in December, 2001. SABER is designed to provide measurements of the key radiative and chemical sources and sinks of energy in the mesosphere and lower thermosphere (MLT). SABER measures Earth limb emission in 10 broadband radiometer channels ranging from 1.27 micrometers to 17 micrometers. Measurements are made both day and night over the latitude range from 54 deg. S to 87 deg. N with alternating hemisphere coverage every 60 days. In this paper we concentrate on retrieved profiles of kinetic temperature (T(sub k)) and CO2 volume mixing ratio (vmr), inferred from SABER-observed 15 micrometer and 4.3 micrometer limb emissions, respectively. SABER-measured limb radiances are in non-local thermodynamic equilibrium (non-LTE) in the MLT region. The complexity of non-LTE radiation transfer combined with the large volume of data measured by SABER requires new retrieval approaches and radiative transfer techniques to accurately and efficiently retrieve the data products. In this paper we present the salient features of the coupled non-LTE T(sub k)/CO2 retrieval algorithm, along with preliminary results.

  6. Retrieval of kinetic temperature and carbon dioxide from measurements of broadband Earth limb emission taken from the TIMED/SABER instrument

    NASA Astrophysics Data System (ADS)

    Mertens, C. J.; Russell, J. M.; Mlynczak, M. G.; She, C.-Y.; Schmidlin, F. J.; Goldberg, R. A.; Saber Team

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment was launched onboard the TIMED satellite in December 2001. SABER has beendesigned to provide measurements of the key radiative and chemical sources and sinks of energy in the mesosphere and lower thermosphere (MLT), in order to achieve major advances in understanding the structure, energetics, chemistry, and dynamics of the MLT region from 60-180 km. SABER measures Earth limb emission in 10 broadband radiometer channels ranging from 1.27 um to 15 um. Measurements aremade both day and night over the latitude range from 54S to 87N with alternating hemisphere coverage every 60 days. The continuous sounding of SABER provides 2200 vertical scans of limb radiance per channel per day, which are used to retrieve vertical profiles, with 2 km altitude resolution, of kinetic temperature (Tk), O3, H2O, and CO2 volume mixing ratios (vmr), and volume emission rates fromO2(1-delta), OH(v=3-5), OH(v=7-9), and NO.MLT infrared limb emissions are in non-local thermodynamic equilibrium (non-LTE), requiring complex non-LTE radiation transfer algorithms and novel retrieval approaches to derive the key data products. In this paper we concentrate on Tk and CO2, which are retrieved simultaneously from SABER's 15 um and 4.3 um radiometer channels, respectively. We show SABER Tk/CO2 results at mid-latitudes and during polar summer and winter seasons, along with Tk comparisons with ground-based and in-situ measurements. SABER-lidar Tk comparisons at Fort Collins, CO provide an indirect validation of the SABER-retrieved CO2 profiles.

  7. Kinetics of the drying process of an anti-adherent coating using Photothermal Radiometry and Micro-Raman

    NASA Astrophysics Data System (ADS)

    Hurtado-Castañeda, D. M.; Fernández, J.; Velázquez, R.; Estévez, M.; Vargas, S.; Rodríguez, R.; Rodríguez, M. E.

    2005-06-01

    The kinetics of the drying process of a new anti-adherent (anti-graffiti) polymeric coating containing organic solvent was determined using Photothermal Radiometry (PTR) and Micro-Raman (μ-R) Spectroscopy. PTR Spectroscopy was used to study, in real time, the kinetics of the drying process in samples protected with coatings with and without anti-adherent molecules. These were applied on a metal and silicon substrates. The PTR spectrum for coating without anti-adherent, shows a single relaxation time, while for coating containing anti-adherent shows two relaxation times corresponding to two different mechanisms: the solvent evaporation and the molecular re-arrangements of the two different molecular species present in the coating; the kinetic of the solvent evaporation is strongly dependent, as expected, on the solvent concentration.

  8. Quantitative evaluation of simulated human enamel caries kinetics using photothermal radiometry and modulated luminescence

    NASA Astrophysics Data System (ADS)

    Hellen, Adam; Mandelis, Andreas; Finer, Yoav; Amaechi, Bennett T.

    2011-03-01

    Photothermal radiometry and modulated luminescence (PTR-LUM) is a non-destructive methodology applied toward the detection, monitoring and quantification of dental caries. The purpose of this study was to evaluate the efficacy of PTRLUM to detect incipient caries lesions and quantify opto-thermophysical properties as a function of treatment time. Extracted human molars (n=15) were exposed to an acid demineralization gel (pH 4.5) for 10 or 40 days in order to simulate incipient caries lesions. PTR-LUM frequency scans (1 Hz - 1 kHz) were performed prior to and during demineralization. Transverse Micro-Radiography (TMR) analysis followed at treatment conclusion. A coupled diffusephoton- density-wave and thermal-wave theoretical model was applied to PTR experimental amplitude and phase data across the frequency range of 4 Hz - 354 Hz, to quantitatively evaluate changes in thermal and optical properties of sound and demineralized enamel. Excellent fits with small residuals were observed experimental and theoretical data illustrating the robustness of the computational algorithm. Increased scattering coefficients and poorer thermophysical properties were characteristic of demineralized lesion bodies. Enhanced optical scattering coefficients of demineralized lesions resulted in poorer luminescence yield due to scattering of both incident and converted luminescent photons. Differences in the rate of lesion progression for the 10-day and 40-day samples points to a continuum of surface and diffusion controlled mechanism of lesion formation. PTR-LUM sensitivity to changes in tooth mineralization coupled with opto-thermophysical property extraction illustrates the technique's potential for non-destructive quantification of enamel caries.

  9. Influence of Solar-Geomagnetic Disturbances on SABER Measurements of 4.3 Micrometer Emission and the Retrieval of Kinetic Temperature and Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Winick, Jeremy R.; Picard, Richard H.; Evans, David S.; Lopez-Puertas, Manuel; Wintersteiner, Peter P.; Xu, Xiaojing; Mlynczak, Martin G.; Russell, James M., III

    2008-01-01

    Thermospheric infrared radiance at 4.3 micrometers is susceptible to the influence of solar-geomagnetic disturbances. Ionization processes followed by ion-neutral chemical reactions lead to vibrationally excited NO(+) (i.e., NO(+)(v)) and subsequent 4.3 micrometer emission in the ionospheric E-region. Large enhancements of nighttime 4.3 m emission were observed by the TIMED/SABER instrument during the April 2002 and October-November 2003 solar storms. Global measurements of infrared 4.3 micrometer emission provide an excellent proxy to observe the nighttime E-region response to auroral dosing and to conduct a detailed study of E-region ion-neutral chemistry and energy transfer mechanisms. Furthermore, we find that photoionization processes followed by ion-neutral reactions during quiescent, daytime conditions increase the NO(+) concentration enough to introduce biases in the TIMED/SABER operational processing of kinetic temperature and CO2 data, with the largest effect at summer solstice. In this paper, we discuss solar storm enhancements of 4.3 micrometer emission observed from SABER and assess the impact of NO(+)(v) 4.3 micrometer emission on quiescent, daytime retrievals of Tk/CO2 from the SABER instrument.

  10. Estimated synoptic distributions of SABER data

    NASA Astrophysics Data System (ADS)

    Lingenfelser, G.; Remsberg, E.; Harvey, V.; Grose, W.

    2003-04-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument aboard the TIMED (Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics) satellite has been obtaining measurements since January 2002. The Version 1.01 Level 2A LTE temperature data have been compared with temperature data obtained by other satellites, lidars, and falling spheres. The agreement between the SABER temperature profiles and those for other data sets indicate that the Version 1.01 SABER LTE temperature versus pressure distributions are suitable to use in dynamical studies of the middle atmosphere through the calculation of winds and potential vorticity. A first step in the calculation of dynamical parameters is to use a sequential estimation technique to obtain synoptic temperature distributions from the asynoptic SABER satellite data. The algorithm that was used in the LIMS data mapping has been updated and applied to the SABER temperature data to generate Fourier coefficients which are output at noon UT for each day as a function of latitude. From these spectral coefficients, synoptic temperature fields are estimated. The estimated data will be compared with assimilated fields in an attempt to further assess the quality of the SABER data.

  11. Theory of zone radiometry

    NASA Technical Reports Server (NTRS)

    Farmer, R. C.; Audeh, B. J.

    1973-01-01

    A spectroscopic instrumentation system was developed which was used to measure temperature and concentration distributions in axisymmetric and two dimensional combusting flows. This measurement technique is known as zone radiometry.

  12. SABER Optical Design

    SciTech Connect

    Erickson, R.; Bane, K.; Emma, P.; Nosochkov, y.; /SLAC

    2006-07-07

    SABER, the South Arc Beam Experimental Region, is a proposed new beam line facility designed to replace the Final Focus Test Beam at SLAC. In this paper, we outline the optical design features and beam parameters now envisioned for SABER. A magnetic chicane to compress positron bunches for SABER and a bypass line that could transport electrons or positrons from the two-thirds point of the linac to SABER, bypassing the LCLS systems, are also discussed.

  13. On the weighting of SABER temperature profiles for comparison with ground based hydroxyl rotational temperatures.

    NASA Astrophysics Data System (ADS)

    French, William; Mulligan, Frank

    2010-05-01

    Kinetic temperature profiles are retrieved from limb-emission radiance measurements of CO2 at 15 and 4.3 um by the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument on the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) satellite. Profiles extend from about 20-120km and measurements are available since the spacecraft launch in Dec-2001. Hydroxyl (6-2) band rotational temperatures are measured using a ground-based scanning spectrometer at Davis station, Antarctica (68°S, 78°E). Measurements are available each year since 1995 on nights between early February and late October, when the sun is more than 6° below the horizon. In order to compare temperatures from these two instruments we must derive hydroxyl layer equivalent temperatures for the SABER profiles using a weighting function which represents the hydroxyl layer profile. In this study, we examine a number of different weighting profiles to determine the best equivalent to hydroxyl nightly average temperatures at Davis. These profiles include (1) the customary Gaussian peaked at 87km and width 8km [Baker and Stair, 1988 :Physica Scripta. 37 611-622], (2) the layer profile derived from WINDIIUARS hydroxyl height profiles [She and Lowe, 1998 :JASTP 60, 1573-1583], (3) layer profiles derived from the hydroxyl volume emission rate (VER) from the SABER OH-B channel at 1.6um, which contains the Meinel OH(4-2) and OH(5-3) bands and (4) a Gaussian fitted to the SABER hydroxyl VER peak. The comparison is made with approximately 2500 SABER retrievals from overpasses within 500km of Davis station, and with solar zenith angle >97°, which have coincident hydroxyl temperature measurements over the 8 winters between 2002 and 2009. Due to the satellite 60 day yaw cycle the sampling over Davis has occurred in approximately the same three time intervals each year; between days 75-140, 196-262 and 323-014, however the latter interval is entirely rejected on the solar zenith

  14. Analysis of the February 2002 stratospheric warming using SABER data

    NASA Astrophysics Data System (ADS)

    Grose, W.; Lingenfelser, G.; Remsberg, E.; Harvey, V.

    2003-04-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument began acquiring data in January 2002. Version 1.01 Level 2A LTE temperature data have been compared with various correlative data sources (e.g. satellites, lidar, and falling spheres). These results generally show good agreement in the stratosphere. Synoptic temperature distributions are being generated from the SABER data using a sequential estimation technique which was developed for the use with the Nimbus 7 LIMS data. From these temperature distributions, corresponding synoptic fields of geopotential height and geostrophic winds can be obtained. The evolution of the lower stratosphere of the Northern Hemisphere during the warming of February 2002 will be analyzed using these SABER data and compared with a similar analysis using assimilated data.

  15. Microwave radiometry and applications

    NASA Astrophysics Data System (ADS)

    Polívka, Jiří

    1995-09-01

    The radiometry in general is a method of detecting the radiation of matter. All material bodies and substances radiate energy in the form of electromagnetic waves according to Planck s Law. The frequency spectrum of such thermal radiation is determined, beyond the properties of a blackbody, by the emissivity of surfaces and by the temperature of a particular body. Also, its reflectivity and dispersion take part. Investigating the intensity of radiation and its spectral distribution, one may determine the temperature and characterize the radiating body as well as the ambient medium, all independently of distance. With the above possibilities, the radiometry represents a base of scientific method called remote sensing. Utilizing various models, temperature of distant bodies and images of observed scenes can be determined from the spatial distribution of radiation. In this method, two parameters are of paramount importance: the temperature resolution, which flows out from the detected energy, and the spatial resolution (or, angular resolution), which depends upon antenna size with respect to wavelength. An instrument usable to conduct radiometric observations thus consists of two basic elements: a detector or radiometer, which determines the temperature resolution, and an antenna which determines the angular or spatial resolution. For example, a photographic camera consists of an objective lens (antenna) and of a sensitive element (a film or a CCD). In remote sensing, different lenses and reflectors and different sensors are employed, both adjusted to a particular spectrum region in which certain important features of observed bodies and scenes are present: frequently, UV and IR bands are used. The microwave radiometry utilizes various types of antennas and detectors and provides some advantages in observing various scenes: the temperature resolution is recently being given in milikelvins, while the range extends from zero to millions of Kelvins. Microwaves also offer

  16. Fourteen Years of Atomic Hydrogen from SABER

    NASA Astrophysics Data System (ADS)

    Hunt, L. A.; Mlynczak, M. G.

    2015-12-01

    We present results for atomic hydrogen in the mesopause region (80-100 km) derived from measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the TIMED satellite. SABER has been measuring the vertical distribution of infrared radiation emitted by various atmospheric gases for nearly 14 years, providing important information about chemical species, including atomic oxygen, atomic hydrogen, ozone and hydroxyl; temperature; and the radiation budget in the upper atmosphere. The methodology for the derivation of daytime and nighttime concentrations and volume mixing ratios will be presented. Zonal mean and global average daytime and nighttime concentrations of H, which demonstrate excellent agreement between 87 and 95 km, have been calculated and the results are compared with observations from the Solar Mesosphere Explorer (SME) satellite made nearly 30 years ago. Variability over the course of the SABER mission will be shown, including the apparent inverse dependence on the solar cycle, which stems from the temperature dependence of various reaction rate coefficients for H photochemistry. Results for H near solar max will be compared for Solar Cycles 23 and 24.

  17. The SABER Experiment on the TIMED Mission: The Operational Data Processing System

    NASA Astrophysics Data System (ADS)

    Gordley, L. L.; Marshall, B. T.; Mertens, C. J.; Wang, Y.; Jacobson, S. B.; Burton, J. C.; Russell, J. M.; Mlynczak, M. G.

    2002-05-01

    This paper will review the system (both software and hardware) used for operational processing of data taken by SABER (Sounding of the Atmosphere using Broadband Emission Radiometry). The SABER experiment was launched aboard the TIMED satellite December 7, 2001 and began science operations January 8, 2002. SABER data will be used to refine the understanding of dynamical and photo-chemical processes in the mesosphere and lower thermosphere. Code for analyzing SABER measurments must rigorously model non-LTE (Local Thermodynamic Equilibrium) processes. If data inversion is to proceed at speeds matching or exceeding measurment collection, then operational processing demands both fast robust radiative transfer codes and efficient computer architecture. The operational codes developed for SABER are based on the rapid GATS BANDPAK algorithms and validated by results from several independent non-LTE research models. Executing these codes on a Beowulf PC cluster enables operational processing at data collection speeds with rigorous and fully coupled non-LTE models.

  18. Landsat Radiometry Project

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This final report summarizes three years of work characterizing the radiometry of the Landsat 4, 5 and 7 Thematic Mappers. It is divided into six sections that are representative of the major areas of effort: 1) Internal Calibrator Lamp Monitoring; 2) Vicarious Calibration; 3) Relative Gain Analysis; 4) Outgassing; 5) Landsat 4 Absolute Calibration; and 6) Landsat 5 Scene Invariant Analysis. Each section provides a summary overview of the work that has been performed at SDSU. Major results are highlighted. In several cases, references are given to publications that have developed from this work, Several team members contributed to this report: Tim Ruggles, Dave Aaron, Shriharsha Madhavan, Esad Micijevic, Cory Mettler, and Jim Dewald. At the end of the report is a summary section.

  19. "Saber" and "Conocer."

    ERIC Educational Resources Information Center

    Taylor, Kathy

    1985-01-01

    Attempts to redefine the meaning of the two Spanish verbs "saber" and "conocer" and explores some possible extralinguistic factors affecting their usage. Shows that "conocer" represents knowledge which is firsthand and that this type of knowledge is a building block for the more thorough, systematic knowledge represented by "saber." (SED)

  20. Digital Receiver for Microwave Radiometry

    NASA Technical Reports Server (NTRS)

    Ellingson, Steven W.; Hampson, Grant A.; Johnson, Joel T.

    2005-01-01

    A receiver proposed for use in L-band microwave radiometry (for measuring soil moisture and sea salinity) would utilize digital signal processing to suppress interfering signals. Heretofore, radio frequency interference has made it necessary to limit such radiometry to a frequency band about 20 MHz wide, centered at .1,413 MHz. The suppression of interference in the proposed receiver would make it possible to expand the frequency band to a width of 100 MHz, thereby making it possible to obtain greater sensitivity and accuracy in measuring moisture and salinity

  1. Multibaseline gravitational wave radiometry

    NASA Astrophysics Data System (ADS)

    Talukder, Dipongkar; Mitra, Sanjit; Bose, Sukanta

    2011-03-01

    We present a statistic for the detection of stochastic gravitational wave backgrounds (SGWBs) using radiometry with a network of multiple baselines. We also quantitatively compare the sensitivities of existing baselines and their network to SGWBs. We assess how the measurement accuracy of signal parameters, e.g., the sky position of a localized source, can improve when using a network of baselines, as compared to any of the single participating baselines. The search statistic itself is derived from the likelihood ratio of the cross correlation of the data across all possible baselines in a detector network and is optimal in Gaussian noise. Specifically, it is the likelihood ratio maximized over the strength of the SGWB and is called the maximized-likelihood ratio (MLR). One of the main advantages of using the MLR over past search strategies for inferring the presence or absence of a signal is that the former does not require the deconvolution of the cross correlation statistic. Therefore, it does not suffer from errors inherent to the deconvolution procedure and is especially useful for detecting weak sources. In the limit of a single baseline, it reduces to the detection statistic studied by Ballmer [Classical Quantum Gravity 23, S179 (2006).CQGRDG0264-938110.1088/0264-9381/23/8/S23] and Mitra et al. [Phys. Rev. DPRVDAQ1550-7998 77, 042002 (2008).10.1103/PhysRevD.77.042002]. Unlike past studies, here the MLR statistic enables us to compare quantitatively the performances of a variety of baselines searching for a SGWB signal in (simulated) data. Although we use simulated noise and SGWB signals for making these comparisons, our method can be straightforwardly applied on real data.

  2. Cementum on Smilodon sabers.

    PubMed

    Riviere, Holliston L; Wheeler, H Todd

    2005-07-01

    The maxillary canines of Smilodon californicus Bovard, 1907 have a deeply curved cementoenamel junction. The gingiva of modern cats is attached to the tooth at the cementoenamel junction and provides tactile and other dental information to the animal. The presence of cementum at the cervix of the maxillary canines, also called sabers, would indicate that the gingiva in Smilodon was attached in this region. Such an attachment would be advantageous, providing stability and sensory input for the large tooth. Also, gingiva at the cervix would impact the manner in which the teeth were used. Previous study using scanning electron microscopy of dental casts was indirect. The purpose of this study was to confirm by direct methods the presence of cementum at the cervix of Smilodon californicus sabers. Parts of three Smilodon californicus sabers were sectioned and examined with light and scanning electron microscopy (EDS). In addition, percent weight of calcium and phosphorus was measured in enamel, dentin, and cementum using electron dispersive spectroscopy. Cementum was identified in the cervical region of each saber. Spectroscopy confirmed that the tissue is calcified and the mineral is hydroxyapatite. Percent calcium and percent phosphorus of individual tissues were highly variable between specimens. However, the ratios of calcium to phosphorus were not significantly different from the hydroxyapatite standard. In the future, bite models will have to take the presence of soft tissues into account.

  3. Performance analysis in saber.

    PubMed

    Aquili, Andrea; Tancredi, Virginia; Triossi, Tamara; De Sanctis, Desiree; Padua, Elvira; DʼArcangelo, Giovanna; Melchiorri, Giovanni

    2013-03-01

    Fencing is a sport practiced by both men and women, which uses 3 weapons: foil, épée, and saber. In general, there are few scientific studies available in international literature; they are limited to the performance analysis of fencing bouts, yet there is nothing about saber. There are 2 kinds of competitions in the World Cup for both men and women: the "FIE GP" and "A." The aim of this study was to carry out a saber performance analysis to gain useful indicators for the definition of a performance model. In addition, it is expected to verify if it could be influenced by the type of competition and if there are differences between men and women. Sixty bouts: 33 FIE GP and 27 "A" competitions (35 men's and 25 women's saber bouts) were analyzed. The results indicated that most actions are offensive (55% for men and 49% for women); the central area of the piste is mostly used (72% for men and 67% for women); the effective fighting time is 13.6% for men and 17.1% for women, and the ratio between the action and break times is 1:6.5 for men and 1:5.1 for women. A lunge is carried out every 23.9 seconds by men and every 20 seconds by women, and a direction change is carried out every 65.3 seconds by men and every 59.7 seconds by women. The data confirm the differences between the saber and the other 2 weapons. There is no significant difference between the data of the 2 different kinds of competitions.

  4. Atomic Hydrogen in the Mesopause Region Derived From the SABER Instrument

    NASA Astrophysics Data System (ADS)

    Martin-Torres, F. J.; Mlynczak, M. G.; Russell, J. M.; Marsh, D.; Smith, A.

    2005-12-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument simultaneously measures temperature, density, ozone, and emission from the high-lying states of the hydroxyl (OH) radical. Near the mesopause the excited OH states are produced directly from the reaction of atomic hydrogen and ozone. Measurements of emission from these states can be used to derive the density of atomic hydrogen in the airglow layer of this region. SABER is now providing measurements of atomic hydrogen continuously, night and day. In this paper we review the derivation of the atomic hydrogen from SABER measurements and compare results with photochemical model calculations. The uncertainty of the H abundance due to the non-LTE rate coefficients used in the analysis of the OH airglow is also assessed.

  5. Optical and solar radiometry standards and traceability

    SciTech Connect

    Wells, C.V.

    1995-09-01

    This paper presents an overview of the concept of traceability for optical and solar radiometry measurements, current measurement standards and consensus standards, and measurement uncertainty analysis. The inter-relationships between traceability, standards and uncertainty will be shown. This overview will provide some foundations for other papers in this Workshop. In the late 1970`s, the solar energy research community encountered difficulties when comparing efficiency measurements of flat-plate solar thermal collectors-the efficiency measurements and tests made at participating laboratories revealed differences that were larger than would be expected from the errors believed to be present in the measurement processes used then. The differences were found to be largely due to the solar radiation measurements. There are lessons to be learned from that situation for PV radiometry activities. The concept of traceability and its impact on PV radiometry, is explained and related to standards and calibration, measurement uncertainty analysis, measurement standards, consensus standards, and measurement quality assurance. The concept of traceability and its impact on PV radiometry, is explained and related to standards and calibration, measurement uncertainty analysis, measurement standards, consensus standards, and measurement quality assurance. The measurement reference standards that support the PV optical and solar radiometry will be described. Basic concepts of measurement uncertainty analysis will be highlighted, and extensive references to the literature are given. Consensus standards applicable to PV radiometry work will be noted.

  6. Energetics of the Thermosphere in Polar Regions Observed by SABER

    NASA Astrophysics Data System (ADS)

    Hunt, L. A.; Mlynczak, M. G.

    2015-12-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on NASA's TIMED satellite has been measuring the vertical distribution of infrared radiation emitted by various atmospheric gases for nearly 14 years, providing important information about chemical species, including atomic oxygen, hydrogen, ozone and hydroxyl; temperature; and the radiation budget in the upper atmosphere. From these measurements, the infrared power and energy radiated by nitric oxide (NO) at 5.3 µm and carbon dioxide (CO2) at 15 µm have been computed. These infrared emissions have been shown to be a mechanism for the dissipation of the atmospheric heating that results from geoeffective solar storm energy, serving as a natural thermostat to cool the atmosphere to pre-storm conditions. We present the response in the polar region to several storm events that have occurred during the SABER mission, including the location of maximum response and a comparison of the relative NO and CO2 cooling that occurred, since they are each driven by different factors.

  7. Simultaneous retrieval of T(p) and CO2 VMR from two-channel non-LTE limb radiances and application to daytime SABER/TIMED measurements

    NASA Astrophysics Data System (ADS)

    Rezac, L.; Kutepov, A.; Russell, J. M.; Feofilov, A. G.; Yue, J.; Goldberg, R. A.

    2015-08-01

    The kinetic temperature, Tk, and carbon dioxide, CO2 density, are key parameters that characterize the energetics and dynamics of the mesosphere and lower thermosphere (MLT) region. The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on-board the Thermosphere-Ionosphere-Mesosphere-Energetics and Dynamics (TIMED) satellite has been providing global, simultaneous measurements of limb radiance in 10 spectral channels continuously since late January 2002. In this paper we (1) present a methodology for a self-consistent simultaneous retrieval of temperature/pressure, Tk(p), and CO2 volume mixing ratio (VMR) from the broadband infrared limb measurements in the 15 and 4.3 μm channels, and (2) qualitatively describe the first results on the CO2 VMR and Tk obtained from application of this technique to the SABER 15 and 4.3 μm channels, including issues, which demand additional constraints to be applied. The self-consistent two-channel retrieval architecture updates parameters at all altitudes simultaneously, and it is built upon iterative switching between two retrieval modules, one for CO2 and one for Tk. A detailed study of sensitivity, stability and convergence was carried out to validate the algorithm. The Tk/CO2 VMR distribution can be reliably retrieved without biases connected with this non-linear inverse problem starting with an initial guess as far as ±20% of CO2 VMR and ±15 K from the solution (as global shift, or somewhat larger if only local deviations are considered). In polar summer toward high latitudes the retrieved CO2 VMR profile shows a local peak around 90 km. We discuss details of this feature and show that: (a) it is not an algorithm artifact or instability, (b) additional a priori constraints are needed in order to obtain a physical profile and to remove this peak, and (c) several possibilities are explored as to uncover the real cause of this feature, but no firm conclusion can be reached at this time. This

  8. Scientific results from the SABER Experiment on the TIMED Satellite: 2002 - 2011

    NASA Astrophysics Data System (ADS)

    Russell, J. M.; Mlynczak, M. G.

    2011-12-01

    The primary science goal of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment on the TIMED satellite is to achieve major advances in understanding the structure, energetics, chemistry, and dynamics in the atmospheric region extending from 60 to 180 km altitude. The SABER instrument has been observing the atmosphere nearly continuously since data collection began in January of 2002 using the technique of spectral broadband limb emission radiometry applied in 10 infrared spectral bands ranging from 1.27 to 17μm. Four bands - three in the 15μm band and one in the 4.3μm band of CO2, are used to retrieve temperature and CO2 concentrations and to correct retrievals for spacecraft motion effects. The remaining bands are used to retrieve O3, H2O, [O], [H],and energetics parameters, and to measure atmospheric heating and cooling. The measured limb emission profiles are being processed on the ground to provide vertical temperature, constituent and other parameter profiles with 2 km altitude resolution. Measurements are made both night and day over the latitude range from 52 degrees to 83 degrees with alternating hemisphere coverage every 60 days. During the time SABER has been operating, many solar storms have occurred and data have been collected over the range from solar maximum in 2002 to the 2009 solar minimum and up to the present day. The temporal and geographic coverage provided by SABER has provided path finding observations on the atmospheric effects of these events. In addition, the battery of measurements made by SABER has yielded new information on atmospheric energetics effects over the solar cycle including radiative cooling due to the 15μm CO2 and 5.3μm NO bands. Numerous synergistic science studies have been conducted with data from the AIM satellite that is dedicated to the study of noctilucent clouds (NLCs) including the driving parameters that control the start and end of the NLC season, the relationship between

  9. Biomedical imaging with radio-frequency radiometry

    NASA Astrophysics Data System (ADS)

    Nguyen, Andrew

    2009-03-01

    We present a technique for biomedical imaging without radiation. The technique is based on the principles of thermal radiation and RF radiometry, which can be used to generate tomographic images for medical diagnosis such as early detection of breast cancer. Thermal radiation refers to the blackbody radiation emitted by matter, which extends all through the electromagnetic spectrum. By wirelessly measuring this thermal radiation transmitted by the patient's body and internal tissues at RF frequencies using RF radiometry, a mapping of the temperature distribution can be established, from which information such as images of the body and internal tissues can be formed. Biomedical imaging using RF radiometry is valuable for biomedical imaging applications as it promises to retain the full benefits of RF imaging without exposing patients to radiation, thus benefiting not only patients but also health-care professionals and industries.

  10. Increasing carbon dioxide concentration in the upper atmosphere observed by SABER

    NASA Astrophysics Data System (ADS)

    Yue, Jia; Russell, James; Jian, Yongxiao; Rezac, Ladislav; Garcia, Rolando; López-Puertas, Manuel; Mlynczak, Martin G.

    2015-09-01

    Carbon dioxide measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument between 2002 and 2014 were analyzed to reveal the rate of increase of CO2 in the mesosphere and lower thermosphere. The CO2 data show a trend of ~5% per decade at ~80 km and below, in good agreement with the tropospheric trend observed at Mauna Loa. Above 80 km, the SABER CO2 trend is larger than in the lower atmosphere, reaching ~12% per decade at 110 km. The large relative trend in the upper atmosphere is consistent with results from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). On the other hand, the CO2 trend deduced from the Whole Atmosphere Community Climate Model remains close to 5% everywhere. The spatial coverage of the SABER instrument allows us to analyze the CO2 trend as a function of latitude for the first time. The trend is larger in the Northern Hemisphere than in the Southern Hemisphere mesopause above 80 km. The agreement between SABER and ACE-FTS suggests that the rate of increase of CO2 in the upper atmosphere over the past 13 years is considerably larger than can be explained by chemistry-climate models.

  11. Increasing carbon dioxide concentration in the upper atmosphere observed by SABER

    NASA Astrophysics Data System (ADS)

    Yue, J.; Russell, J. M., III; Jian, Y.; Rezac, L.; Garcia, R. R.; Lopez-Puertas, M.; Mlynczak, M. G.

    2015-12-01

    Carbon dioxide measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument between 2002 and 2014 were analyzed to reveal the rate of increase of CO2 in the mesosphere and lower thermosphere. The CO2 data show a trend of ~5% per decade at ~80 km and below, in good agreement with the tropospheric trend observed at Mauna Loa. Above 80 km, the SABER CO2 trend is larger than in the lower atmosphere, reaching ~12% per decade above 110 km. The large relative trend in the upper atmosphere is consistent with results from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). On the other hand, the CO2 trend deduced from the Whole Atmosphere Community Climate Model (WACCM) remains close to 5% everywhere. The spatial coverage of the SABER instrument allows us to analyze the CO2 trend as a function of latitude for the first time. The trend is larger in the northern hemisphere than in the southern hemisphere mesopause above 80 km. The agreement between SABER and ACE-FTS suggests that the rate of increase of CO2 in the upper atmosphere over the past 13 years is considerably larger than can be explained by chemistry-climate models.

  12. Profiling Atmospheric Water Vapor by Microwave Radiometry.

    NASA Astrophysics Data System (ADS)

    Wang, J. R.; King, J. L.; Wilheit, T. T.; Szejwach, G.; Gesell, L. H.; Nieman, R. A.; Niver, D. S.; Krupp, B. M.; Gagliano, J. A.

    1983-05-01

    High-altitude microwave radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric water vapor profiles over both land and water. An algorithm based on an extended Kaiman-Bucy filter was implemented and applied for the water vapor retrieval. The results show great promise in atmospheric water vapor profiling by microwave radiometry heretofore not attainable at lower frequencies.

  13. Profiling atmospheric water vapor by microwave radiometry

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Wilheit, T. T.; Szejwach, G.; Gesell, L. H.; Nieman, R. A.; Niver, D. S.; Krupp, B. M.; Gagliano, J. A.; King, J. L.

    1983-01-01

    High-altitude microwave radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric water vapor profiles over both land and water. An algorithm based on an extended kalman-Bucy filter was implemented and applied for the water vapor retrieval. The results show great promise in atmospheric water vapor profiling by microwave radiometry heretofore not attainable at lower frequencies.

  14. Profiling atmospheric water vapor by microwave radiometry

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Wilheit, T. T.; Szejwach, G.; Gesell, L. H.; Nieman, R. A.; Niver, D. S.; Krupp, B. M.; Gagliano, J. A.; King, J. L.

    1983-01-01

    High-altitude microwave radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric water vapor profiles over both land and water. An algorithm based on an extended kalman-Bucy filter was implemented and applied for the water vapor retrieval. The results show great promise in atmospheric water vapor profiling by microwave radiometry heretofore not attainable at lower frequencies.

  15. Optical stability testing of the fiber support technology (FiST) focal plane assembly of the SABER instrument

    NASA Astrophysics Data System (ADS)

    Jensen, Scott M.; Batty, J. Clair; Esplin, Roy W.; Felt, Matthew J.

    1998-09-01

    The focal plane assembly of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument is supported using Fiber Support Technology (FiST) which utilizes high performance fibers in tension to mechanically support and thermally isolate a cooled component from a warm environment. Details of this approach were presented in detail at SPIE meeting in Denver in 1996. The SABER team deemed it necessary to perform optical stability testing on this never-before-flown technology for supporting focal plane assemblies to determine if precise positioning could be maintained through vibration and thermal cycling. After subjecting the support system to vibration and thermal cycling, the angular orientation between the warm outer support structure and the inner cold block was measured. Since the outer support structure serves as the reference location for positioning the focal plane assembly and the cold block is where the detectors reside, it was possible to determine if FiST meets the optical stability requirements for the SABER instrument. The results from this testing are presented, discussed, and compared to the optical requirements of the SABER instrument. A brief summary of current thermal and mechanical enhancements to the system will also be discussed.

  16. Water vapor radiometry research and development phase

    NASA Technical Reports Server (NTRS)

    Resch, G. M.; Chavez, M. C.; Yamane, N. L.; Barbier, K. M.; Chandlee, R. C.

    1985-01-01

    This report describes the research and development phase for eight dual-channel water vapor radiometers constructed for the Crustal Dynamics Project at the Goddard Space Flight Center, Greenbelt, Maryland, and for the NASA Deep Space Network. These instruments were developed to demonstrate that the variable path delay imposed on microwave radio transmissions by atmospheric water vapor can be calibrated, particularly as this phenomenon affects very long baseline interferometry measurement systems. Water vapor radiometry technology can also be used in systems that involve moist air meteorology and propagation studies.

  17. Submillimeter-Wave Cloud Ice Radiometry

    NASA Technical Reports Server (NTRS)

    Walter, Steven J.

    1999-01-01

    Submillimeter-wave cloud ice radiometry is a new and innovative technique for characterizing cirrus ice clouds. Cirrus clouds affect Earth's climate and hydrological cycle by reflecting incoming solar energy, trapping outgoing IR radiation, sublimating into vapor, and influencing atmospheric circulation. Since uncertainties in the global distribution of cloud ice restrict the accuracy of both climate and weather models, successful development of this technique could provide a valuable tool for investigating how clouds affect climate and weather. Cloud ice radiometry could fill an important gap in the observational capabilities of existing and planned Earth-observing systems. Using submillimeter-wave radiometry to retrieve properties of ice clouds can be understood with a simple model. There are a number of submillimeter-wavelength spectral regions where the upper troposphere is transparent. At lower tropospheric altitudes water vapor emits a relatively uniform flux of thermal radiation. When cirrus clouds are present, they scatter a portion of the upwelling flux of submillimeter-wavelength radiation back towards the Earth as shown in the diagram, thus reducing the upward flux o f energy. Hence, the power received by a down-looking radiometer decreases when a cirrus cloud passes through the field of view causing the cirrus cloud to appear radiatively cool against the warm lower atmospheric thermal emissions. The reduction in upwelling thermal flux is a function of both the total cloud ice content and mean crystal size. Radiometric measurements made at multiple widely spaced frequencies permit flux variations caused by changes in crystal size to be distinguished from changes in ice content, and polarized measurements can be used to constrain mean crystal shape. The goal of the cloud ice radiometry program is to further develop and validate this technique of characterizing cirrus. A multi-frequency radiometer is being designed to support airborne science and

  18. Submillimeter-Wave Cloud Ice Radiometry

    NASA Technical Reports Server (NTRS)

    Walter, Steven J.

    1999-01-01

    Submillimeter-wave cloud ice radiometry is a new and innovative technique for characterizing cirrus ice clouds. Cirrus clouds affect Earth's climate and hydrological cycle by reflecting incoming solar energy, trapping outgoing IR radiation, sublimating into vapor, and influencing atmospheric circulation. Since uncertainties in the global distribution of cloud ice restrict the accuracy of both climate and weather models, successful development of this technique could provide a valuable tool for investigating how clouds affect climate and weather. Cloud ice radiometry could fill an important gap in the observational capabilities of existing and planned Earth-observing systems. Using submillimeter-wave radiometry to retrieve properties of ice clouds can be understood with a simple model. There are a number of submillimeter-wavelength spectral regions where the upper troposphere is transparent. At lower tropospheric altitudes water vapor emits a relatively uniform flux of thermal radiation. When cirrus clouds are present, they scatter a portion of the upwelling flux of submillimeter-wavelength radiation back towards the Earth as shown in the diagram, thus reducing the upward flux o f energy. Hence, the power received by a down-looking radiometer decreases when a cirrus cloud passes through the field of view causing the cirrus cloud to appear radiatively cool against the warm lower atmospheric thermal emissions. The reduction in upwelling thermal flux is a function of both the total cloud ice content and mean crystal size. Radiometric measurements made at multiple widely spaced frequencies permit flux variations caused by changes in crystal size to be distinguished from changes in ice content, and polarized measurements can be used to constrain mean crystal shape. The goal of the cloud ice radiometry program is to further develop and validate this technique of characterizing cirrus. A multi-frequency radiometer is being designed to support airborne science and

  19. Energy Budget of the Thermosphere and Mesosphere from 15 Years of SABER Observations

    NASA Astrophysics Data System (ADS)

    Hunt, L. A.; Mlynczak, M. G.; Marshall, B. T.; Russell, J. M., III

    2016-12-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite has provided nearly 15 years of continuous measurements in the mesosphere and thermosphere and operations are ongoing. The SABER instrument has performed exceptionally well since its launch in December 2001, and several more years of observations are eagerly anticipated. SABER is a limb-scanning instrument that makes vertical profile measurements of infrared radiance in ten channels chosen to permit retrieval or derivation of a variety of data products. These include radiative emission of NO at 5.3 μm and CO2 at 15 μm, two key components that govern radiative cooling of the atmosphere above 100 km. Other channels provide information about the thermal structure and elements of the energy budget of the upper mesosphere. From SABER radiances, we determine amounts of atomic oxygen and hydrogen, radiative cooling by CO2, solar heating by O3 and O2, and chemical heating from a suite of exothermic reactions over the vertical range of 65-100 km. We have observed changes in the energy budgets of these regions from mid-solar cycle 23 to the current downturn in solar cycle 24, encompassing portions of two very different solar cycles and the unusually long solar minimum between them. This talk focuses on the natural variability in the composition and energy budget of the mesosphere and lower thermosphere imposed by the variability of the Sun over the past 15 years.

  20. Revised Correlation between Odin/OSIRIS PMC Properties and Coincident TIMED/SABER Mesospheric Temperatures

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Petelina, S. V.; Kutepov, A. A.; Pesnell, W. D.; Goldberg, R. A.; Llewellyn, E. J.; Russell, J. M.

    2006-01-01

    The Optical Spectrograph and Infrared Imaging System (OSIRIS) instrument on board the Odin satellite detects Polar Mesospheric Clouds (PMCs) through the enhancement in the limb-scattered solar radiance. The Sounding of the Atmosphere using the Broadband Emission Radiometry (SABER) instrument on board the TIMED satellite is a limb scanning infrared radiometer that measures temperature and vertical profiles and energetic parameters for minor constituents in the mesosphere and lower thermosphere. The combination of OSIRIS and SABER data has been previously used to statistically derive thermal conditions for PMC existence [Petelina et al., 2005]. a, A.A. Kutepov, W.D. Pesnell, In this work, we employ the simultaneous common volume measurements of PMCs by OSIRIS and temperature profiles measured by SABER for the Northern Hemisphere summers of 2002-2005 and corrected in the polar region by accounting for the vibrational-vibrational energy exchange among the CO2 isotopes [Kutepov et al., 2006]. For each of 20 coincidences identified within plus or minus 1 degree latitude, plus or minus 2 degrees longitude and less than 1 hour time the frost point temperatures were calculated using the corresponding SABER temperature profile and water vapor densities of 1,3, and 10 ppmv. We found that the PMC presence and brightness correlated only with the temperature threshold that corresponds to the frost point. The absolute value of the temperature below the frost point, however, didn't play a significant role in the intensity of PMC signal for the majority of selected coincidences. The presence of several bright clouds at temperatures above the frost point is obviously related to the limitation of the limb geometry when some near- or far-field PMCs located at higher (and warmer) altitudes appear to be at lower altitudes.

  1. Revised Correlation between Odin/OSIRIS PMC Properties and Coincident TIMED/SABER Mesospheric Temperatures

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Petelina, S V.; Kutepov, A. A.; Pesnell, W. D.; Goldberg, R. A.; Llewellyn, E. J.; Russell, J. M.

    2006-01-01

    The Optical Spectrograph and Infrared Imaging System (OSIRIS) instrument on board the Odin satellite detects Polar Mesospheric Clouds (PMCs) through the enhancement in the limb scattered solar radiance. The Sounding of the Atmosphere using the Broadband Emission Radiometry (SABER) instrument on board the TIMED satellite is a limb scanning infrared radiometer that measures temperature and vertical profiles and energetic parameters for minor constituents in the mesosphere and lower thermosphere. The combination of OSIRIS and SABER data has been previously used to statistically derive thermal conditions for PMC existence [Petelina et al., 2005]. In this work, we employ the simultaneous common volume measurements of PMCs by OSIRIS and temperature profiles measured by SABER for the Northern Hemisphere summers of 2002-2005 and corrected in the polar region by accounting for the vibrational-vibrational energy exchange among the CO2 isotopes [Kutepov et al., 2006]. For each of 20 coincidences identified within plus or minus 1 degree latitude, plus or minus 2 degrees longitude and less than 1 hour time the frost point temperatures were calculated using the corresponding SABER temperature profile and water vapor densities of 1,3, and 10 ppmv. We found that the PMC presence and brightness correlated only with the temperature threshold that corresponds to the frost point. The absolute value of the temperature below the frost point, however, didn't play a significant role in the intensity of PMC signal for the majority of selected coincidences. The presence of several bright clouds at temperatures above the frost point is obviously related to the limitation of the limb geometry when some near- or far-field PMCs located at higher (and warmer) altitudes appear to be at lower altitudes.

  2. SABER-School Finance: Data Collection Instrument

    ERIC Educational Resources Information Center

    King, Elizabeth; Patrinos, Harry; Rogers, Halsey

    2015-01-01

    The aim of the SABER-school finance initiative is to collect, analyze and disseminate comparable data about education finance systems across countries. SABER-school finance assesses education finance systems along six policy goals: (i) ensuring basic conditions for learning; (ii) monitoring learning conditions and outcomes; (iii) overseeing…

  3. 100 years of photometry and radiometry

    NASA Astrophysics Data System (ADS)

    Hardis, Jonathan E.

    2001-06-01

    Measurement of light is an old subject, though the past 100 years have seen significant advances. 100 years ago, photometry - the art and science of measuring light as it is perceived by people - had the greater technological importance. Even today SI (the metric system) retains a base unit for photometry, the candela. However, early work at NBS included pivotal projects in the field of radiometry - the measurement of the physical characteristics of light. These included the validation of Planck's newly-minted theory of blackbody radiation, determining the radiation constants with good accuracy, and the definitive analysis of the spectral responsivity of human vision, so as to relate photometry to radiometry. This latter work has only increased in importance over the past 75 years as the definition of the candela has changed and improved. Today, NIST makes radiometric, and hence photometric measurements, with unprecedented precision. Cryogenic radiometers based on the principle of electrical substitution measure optical flux with uncertainties of 0.02%. Additional facilities enable measurement of spectral responsivity, spectral radiance, and spectral irradiance. Novel detectors, such as light-traps, allow the best accuracy to be transferred from the primary standards to routinely-used instruments and to calibration customers. Filtered detectors are used to realize photometric scales, radiation temperature scales, and other specialized measurements. Indeed, the story of the metrology of light is the story of continuous improvement, both driven by and enabled by advances in technology. We touch upon some of these as a prelude to the other talks in this Conference.

  4. Analysis of dental materials by photothermal radiometry

    NASA Astrophysics Data System (ADS)

    Conde-Contreras, M.; Tiessler, V.; Cucina, A.; Quintana, P.; Alvarado-Gil, Juan J.

    2005-02-01

    The analysis of teeth is an interesting field, given the importance of these pieces for the individual or for humanity in the case of remains recovered from an archeologically site; therefore, the development of non-destructive techniques is important to study these materials. Photothermal techniques are ones of the most interesting possibilities; they are based in the generation of a train of thermal waves inside of a material due to the illumination with modulated light. Among these techniques photothermal radiometry has an outstanding role, since it is a non-contact technique, based in the detection of infrared emission of the samples heated with the laser. The experimental configuration consists of an Ar laser beam that impinges on the surface of the teeth and the infrared radiation generated is measured using a HgCdTe IR detector. Results for the analysis of cracks on teeth and the low frequency profiles are presented. A strong influence of the signal due to the microstructure of teeth is observed. Furthermore, surface effects are analyzed changing the color of teeth when whitening products are applied. The process of whitening is monitored in real time by optical spectroscopy in the visible and by photothermal radiometry.

  5. Estuarine Salinity Mapping From Airborne Radiometry

    NASA Astrophysics Data System (ADS)

    Walker, J. P.; Gao, Y.; Cook, P. L. M.; Ye, N.

    2016-12-01

    Estuaries are critical ecosystems providing both ecological habitat and human amenity including boating and recreational fishing. Salinity gradients, caused by the mixing of fresh and salt water, exert an overwhelming control on estuarine ecology and biogeochemistry as well as being a key tracer for model calibration. At present, salinity monitoring within estuaries typically uses point measurements or underway boat-based methods, which makes sensing of localised phenomena such as upwelling of saline bottom water difficult. This study has pioneered the use of airborne radiometry (passive microwave) sensing as a new method to remotely quantify estuarine salinity, allowing rapid production of high resolution surface salinity maps. The airborne radiometry mapping was conducted for the Gippsland Lakes, the largest estuary in Australia, in February, July, October and November of 2015, using the Polarimetric L-band Microwave Radiometer (PLMR). Salinity was retrieved from the brightness temperature collected by PLMR with results validated against boat sampling conducted concurrently with each flight. Results showed that the retrieval accuracy of the radiative transfer model was better than 5 ppt for most flights. The spatial, temporal and seasonal variations of salinity observed in this study are also analysed and discussed.

  6. Advances in radiometry for ocean color

    USGS Publications Warehouse

    Brown, S.W.; Clark, D.K.; Johnson, B.C.; Yoon, H.; Lykke, K.R.; Flora, S.J.; Feinholz, M.E.; Souaidia, N.; Pietras, C.; Stone, T.C.; Yarbrough, M.A.; Kim, Y.S.; Barnes, R.A.; Mueller, J.L.

    2004-01-01

    We have presented a number of recent developments in radiometry that directly impact the uncertainties achievable in ocean-color research. Specifically, a new (2000) U. S. national irradiance scale, a new LASER-based facility for irradiance and radiance responsivity calibrations, and applications of the LASER facility for the calibration of sun photometers and characterization of spectrographs were discussed. For meaningful long-time-series global chlorophyll-a measurements, all instruments involved in radiometric measurements, including satellite sensors, vicarious calibration sensors, sensors used in the development of bio-optical algorithms and atmospheric characterization need to be fully characterized and corrected for systematic errors, including, but not limited to, stray light. A unique, solid-state calibration source is under development to reduce the radiometric uncertainties in ocean color instruments, in particular below 400 nm. Lunar measurements for trending of on-orbit sensor channel degradation were described. Unprecedented assessments, within 0.1 %, of temporal stability and drift in a satellite sensor's radiance responsivity are achievable with this approach. These developments advance the field of ocean color closer to the desired goal of reducing the uncertainty in the fundamental radiometry to a small component of the overall uncertainty in the derivation of remotely sensed ocean-color data products such as chlorophyll a.

  7. Microwave radiometry; Its importance to the detection of cancer

    SciTech Connect

    Carr, K.L. )

    1989-12-01

    This paper discusses developments in the medical uses of microwave radiometry, particularly in relation to the early detection of cancer, as well as the significance of and progress in related antenna technology.

  8. Viking lander camera radiometry calibration report, volume 1

    NASA Technical Reports Server (NTRS)

    Wolf, M. R.; Atwood, D. L.; Morrill, M. E.

    1977-01-01

    The test methods and data reduction techniques used to determine and remove instrumental signatures from Viking Lander camera radiometry data are described. Gain, offset, and calibration constants are presented in tables.

  9. Advances in Solar Radiometry and Metrology

    SciTech Connect

    Myers, D.; Andreas, A.; Reda, I.; Gotseff, P.; Wilcox, S.; Stoffel, T.; Anderberg, M.

    2005-01-01

    The Solar Radiometry and Metrology task at the National Renewable Energy Laboratory (NREL) provides traceable optical radiometric calibrations and measurements to photovoltaic (PV) researchers and the PV industry. Traceability of NREL solar radiometer calibrations to the World Radiometric Reference (WRR) was accomplished during the NREL Pyrheliometer Comparison in October 2003. The task has calibrated 10 spectral and more than 180 broadband radiometers for solar measurements. Other accomplishments include characterization of pyranometer thermal offset errors with laboratory and spectral modeling tools; developing a simple scheme to correct pyranometer data for known responsivity variations; and measuring detailed spectral distributions of the NREL High Intensity Pulsed Solar Simulator (HIPSS) as a function of lamp voltage and time. The optical metrology functions support the NREL Measurement and Characterization Task effort for ISO 17025 accreditation of NREL Solar Reference Cell Calibrations. Optical metrology functions have been integrated into the NREL quality system and audited for ISO17025 compliance.

  10. Subsurface discontinuity detection by microwave radiometry.

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Edgerton, A. T.

    1971-01-01

    Brief description of a joint program undertaken near Austin and San Antonio, Tex., to detect the presence of subsurface voids such as caverns and tunnels by microwave radiometry. Mi crowave radiometric temperature measurements using both vertical and horizontal polarization were taken with fixed-view angle traverses across three sites at two locations. No unambiguous correlation between the microwave temperature contours and the subsurface voids was observed at either location, but a correlation between microwave temperature and moisture patterns was observed at both locations. The large microwave temperature anomalies observed at all three sites indicated a sensitivity to near-surface structure and moisture distribution. A close correlation was noted between low soil-bearing strength values and the tunnel location at the San Antonio site.

  11. SABER Observations of the OH Meinel Airglow Variability Near the Mesopause

    NASA Technical Reports Server (NTRS)

    Marsh, Daniel R.; Smith, Anne K.; Mlynczak, Martin G.

    2005-01-01

    The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, one of four on board the TIMED satellite, observes the OH Meinel emission at 2.0 m that peaks near the mesopause. The emission results from reactions between members of the oxygen and hydrogen chemical families that can be significantly affected by mesopause dynamics. In this study we compare SABER measurements of OH Meinel emission rates and temperatures with predictions from a 3-dimensional chemical dynamical model. In general, the model is capable of reproducing both the observed diurnal and seasonal OH Meinel emission variability. The results indicate that the diurnal tide has a large effect on the overall magnitude and temporal variation of the emission in low latitudes. This tidal variability is so dominant that the seasonal cycle in the nighttime emission depends very strongly on the local time of the analysis. At higher latitudes, the emission has an annual cycle that is due mainly to transport of oxygen by the seasonally reversing mean circulation.

  12. Geometry and Radiometry Invariant Matched Manifold Detection.

    PubMed

    Sharon, Ran; Francos, Joseph M; Hagege, Rami R

    2017-09-01

    Consider a set of deformable objects undergoing geometric and radiometric transformations. As a result of the action of these transformations, the set of different realizations of each object is generally a manifold in the space of observations. Assuming the geometric deformations an object undergoes, belong to some finite dimensional family, it has been shown that the universal manifold embedding (UME) provides a set of nonlinear operators that universally maps each of the different manifolds, where each manifold is generated by the set all of possible appearances of a single object, into a distinct linear subspace of an Euclidean space. In this paper, we generalize this framework to the case where the observed object undergoes both an affine geometric transformation, and a monotonic radiometric transformation, and present a novel framework for the detection and recognition of the deformable objects. Applying to each of the observations an operator that makes it invariant to monotonic amplitude transformations, but is geometry-covariant with the affine transformation, the set of all possible observations on that object is mapped by the UME into a single linear subspace-invariant with respect to both the geometric and radiometric transformations. The embedding of the space of observations is independent of the specific observed object; hence it is universal. The invariant representation of the object is the basis of a matched manifold detection and tracking framework of objects that undergo complex geometric and radiometric deformations: the observed surface is tessellated into a set of tiles such that the deformation of each one is well approximated by an affine geometric transformation and a monotonic transformation of the measured intensities. Since each tile is mapped by the radiometry invariant UME to a distinct linear subspace, the detection and tracking problems are solved by evaluating distances between linear subspaces. Classification in this context

  13. Mesospheric Water Vapor Retrieved from SABER/TIMED Measurements

    NASA Technical Reports Server (NTRS)

    Feofilov, Arte, G.; Yankovsky, Valentine A.; Marshall, Benjamin T.; Russell, J. M., III; Pesnell, W. D.; Kutepov, Alexander A.; Goldberg, Richard A.; Gordley, Larry L.; Petelina, Svetlama; Mauilova, Rada O.; Garaci-A-Comas, M.

    2007-01-01

    The SABER instrument on board the TIMED satellite is a limb scanning infrared radiometer designed to measure temperature and minor constituent vertical profiles and energetics parameters in the mesosphere and lower thermosphere (MLT) The H2O concentrations are retrieved from 6.3 micron band radiances. The interpretation of this radiance requires developing a non-LTE H2O model that includes energy exchange processes with the system of O3 and O2 vibrational levels populated at the daytime through a number of photoabsorption and photodissociation processes. We developed a research model base on an extended H2O non-LTE model of Manuilova coupled with the novel model of the electronic kinetics of the O2 and O3 photolysis products suggested by Yankosvky and Manuilova. The performed study of this model helped u to develop and test an optimized operational model for interpretation of SABER 6.3 micron band radiances. The sensitivity of retrievals to the parameters of the model is discussed. The H2O retrievals are compared to other measurements for different seasons and locations.

  14. Mesospheric Water Vapor Retrieved from SABER/TIMED Measurements

    NASA Technical Reports Server (NTRS)

    Feofilov, Arte, G.; Yankovsky, Valentine A.; Marshall, Benjamin T.; Russell, J. M., III; Pesnell, W. D.; Kutepov, Alexander A.; Goldberg, Richard A.; Gordley, Larry L.; Petelina, Svetlama; Mauilova, Rada O.; hide

    2007-01-01

    The SABER instrument on board the TIMED satellite is a limb scanning infrared radiometer designed to measure temperature and minor constituent vertical profiles and energetics parameters in the mesosphere and lower thermosphere (MLT) The H2O concentrations are retrieved from 6.3 micron band radiances. The interpretation of this radiance requires developing a non-LTE H2O model that includes energy exchange processes with the system of O3 and O2 vibrational levels populated at the daytime through a number of photoabsorption and photodissociation processes. We developed a research model base on an extended H2O non-LTE model of Manuilova coupled with the novel model of the electronic kinetics of the O2 and O3 photolysis products suggested by Yankosvky and Manuilova. The performed study of this model helped u to develop and test an optimized operational model for interpretation of SABER 6.3 micron band radiances. The sensitivity of retrievals to the parameters of the model is discussed. The H2O retrievals are compared to other measurements for different seasons and locations.

  15. Refinement of Phobos Ephemeris Using Mars Orbiter Laser Altimeter Radiometry

    NASA Technical Reports Server (NTRS)

    Neumann, G. A.; Bills, B. G.; Smith, D. E.; Zuber, M. T.

    2004-01-01

    Radiometric observations from the Mars Orbiter Laser Altimeter (MOLA) can be used to improve the ephemeris of Phobos, with particular interest in refining estimates of the secular acceleration due to tidal dissipation within Mars. We have searched the Mars Orbiter Laser Altimeter (MOLA) radiometry data for shadows cast by the moon Phobos, finding 7 such profiles during the Mapping and Extended Mission phases, and 5 during the last two years of radiometry operations. Preliminary data suggest that the motion of Phobos has advanced by one or more seconds beyond that predicted by the current ephemerides, and the advance has increased over the 5 years of Mars Global Surveyor (MGS) operations.

  16. Refinement of Phobos Ephemeris Using Mars Orbiter Laser Altimeter Radiometry

    NASA Technical Reports Server (NTRS)

    Neumann, G. A.; Bills, B. G.; Smith, D. E.; Zuber, M. T.

    2004-01-01

    Radiometric observations from the Mars Orbiter Laser Altimeter (MOLA) can be used to improve the ephemeris of Phobos, with particular interest in refining estimates of the secular acceleration due to tidal dissipation within Mars. We have searched the Mars Orbiter Laser Altimeter (MOLA) radiometry data for shadows cast by the moon Phobos, finding 7 such profiles during the Mapping and Extended Mission phases, and 5 during the last two years of radiometry operations. Preliminary data suggest that the motion of Phobos has advanced by one or more seconds beyond that predicted by the current ephemerides, and the advance has increased over the 5 years of Mars Global Surveyor (MGS) operations.

  17. Atmospheric Compensation for Uplink Arrays via Radiometry

    NASA Technical Reports Server (NTRS)

    Nessel, James A.; Acosta, Roberto J.

    2010-01-01

    Uplink arrays for communications applications are gaining increased visibility within the NASA and military community due to the enhanced flexibility and reliability they provide. When compared with the conventional large, single aperture antennas currently comprising the Deep Space Network (DSN), for example, smaller aperture antenna arrays have the benefits of providing fault tolerance (reduced single-point failure), reduced maintenance cost, and enhanced capabilities such as electronic beam-steering and multi-beam operation. However, signal combining of antenna array elements spaced many wavelengths apart becomes problematic due to the inherent instability of earth's turbulent atmosphere, particularly at the frequencies of interest to the DSN (i.e., Ka-band). Degradation in the power combining of the individual elements comprising the array arises due to uncorrelated phase errors introduced as the signals propagate through the troposphere. It is well known that the fundamental source of this error is due to the inhomogeneous distribution of water vapor in the atmosphere [1]. Several techniques have been proposed to circumvent this issue, including the use of phase calibration towers and a moon bounce to generate a feedback loop which would provide a means of intermittent calibration of the system phase errors (thermal drifts, atmosphere) [2,3]. However, these techniques require repositioning of the antenna elements to perform this operation which ultimately results in reduced system availability. And, though they are sufficient for compensating for slow varying phase drifts, they are insufficient to compensate for faster varying phase errors, such as those introduced by the atmosphere. In this paper, preliminary radiometry and interferometry measurements collected by the NASA Glenn Research Center are analyzed and indicate that the use of optimized water vapor radiometers as a feedback system in a communications platform could provide the necessary atmospheric

  18. Integration and Enhancement of the Saber Wargame

    DTIC Science & Technology

    1993-12-01

    34dentification to be saved by the component. 77 ACTIVATE Figure 36. State Diagram for Work-Button Object I Modif cmt CREATE BI IDLE MDF Figure 37...cases this can cause images to appear warped when shown on various systems. The solution is to use a unit of length rather than the pixel. Saber uses the

  19. Long-term Changes Of Global Gravity Waves Derived From SABER Temperature Observations

    NASA Astrophysics Data System (ADS)

    Yue, J.; Liu, X.; Xu, J.; Garcia, R. R.; Russell, J. M., III; Mlynczak, M. G.; Wu, D. L.

    2016-12-01

    The global gravity wave (GW) potential energy (PE) per unit mass is derived from SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) temperatures profiles over the past 14 years (2002-2015). Since the SABER data cover longer than one solar cycle, multivariate linear regression is applied to calculate the long-term changes of global GWs and the responses of global GWs to the solar activity, to the QBO (quasi-biennial oscillation) and to the ENSO (El Niño-Southern Oscillation). We find a significant positive long-term change of GW PE at around 60°N in July at 75-90 km, in agreement with the ground radar observations at a similar latitude and height range. Both the monthly and the annual mean long-term changes of GWs are significant at around 60°S. Specifically, the annual mean positive long-term change has a peak of 12-15% per decade at 45°S-60°S and below 80 km, which suggests that eddy diffusion coefficient is increasing in some places. A significant positive long-term change of GWs at around 60°S could be supported by the stronger polar stratospheric jets derived from MERRA (Modern Era Retrospective-analysis for Research and Applications). The response of GWs to solar activity is negative in the lower and middle latitudes and is positive in the higher latitudes. The response of GWs to QBO (as indicated by 30 mb zonal winds over the equator) is negative in the tropical upper stratosphere and extending to higher latitudes at higher altitudes. The response of GWs to ENSO (as indicated by the MEI index) is positive in the tropical upper stratosphere.

  20. Water Vapor, Temperature, and Ice Particles in Polar Mesosphere as Measured by SABER/TIMED and OSIRIS/Odin Instruments

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Petelina, S. V.; Kutepov, A. A.; Pesnell, W. D.; Goldberg, R. A.

    2009-01-01

    Although many new details on the properties of mesospheric ice particles that farm Polar Mesospheric Clouds (PMCs) and also cause polar mesospheric summer echoes have been recently revealed, certain aspects of mesospheric ice microphysics and dynamics still remain open. The detailed relation between PMC parameters and properties of their environment, as well as interseasonal and interhemispheric differences and trends in PMC properties that are possibly related to global change, are among those open questions. In this work, mesospheric temperature and water vapor concentration measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite are used to study the properties of PMCs with respect to the surrounding atmosphere. The cloud parameters, namely location, brightness, and altitude, are obtained from the observations made by the Optical Spectrograph and Infrared Imager System (OSIRIS) on the Odin satellite. About a thousand of simultaneous common volume measurements made by SABER and OSIRIS in both hemispheres from 2002 until 2008 are used. The correlation between PMC brightness (and occurrence rate) and temperatures at PMC altitudes and at the mesopause is analysed. The relation between PMC parameters, frost point temperature, and gaseous water vapor content in and below the cloud is also discussed. Interseasonal and interhemispheric differences and trends in the above parameters, as well as in PMC peak altitudes and mesopause altitudes are evaluated.

  1. Daily estimates of the migrating tide and zonal mean temperature in the mesosphere and lower thermosphere derived from SABER data

    NASA Astrophysics Data System (ADS)

    Ortland, David A.

    2017-04-01

    Satellites provide a global view of the structure in the fields that they measure. In the mesosphere and lower thermosphere, the dominant features in these fields at low zonal wave number are contained in the zonal mean, quasi-stationary planetary waves, and tide components. Due to the nature of the satellite sampling pattern, stationary, diurnal, and semidiurnal components are aliased and spectral methods are typically unable to separate the aliased waves over short time periods. This paper presents a data processing scheme that is able to recover the daily structure of these waves and the zonal mean state. The method is validated by using simulated data constructed from a mechanistic model, and then applied to Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature measurements. The migrating diurnal tide extracted from SABER temperatures for 2009 has a seasonal variability with peak amplitude (20 K at 95 km) in February and March and minimum amplitude (less than 5 K at 95 km) in early June and early December. Higher frequency variability includes a change in vertical structure and amplitude during the major stratospheric warming in January. The migrating semidiurnal tide extracted from SABER has variability on a monthly time scale during January through March, minimum amplitude in April, and largest steady amplitudes from May through September. Modeling experiments were performed that show that much of the variability on seasonal time scales in the migrating tides is due to changes in the mean flow structure and the superposition of the tidal responses to water vapor heating in the troposphere and ozone heating in the stratosphere and lower mesosphere.

  2. Pulsed photothermal radiometry in investigation of tissue destruction caused by CO2 laser action

    NASA Astrophysics Data System (ADS)

    Chebotareva, Galina P.; Zubov, Boris V.; Nikitin, Alexander P.; Rakcheev, Anatolii P.; Alexeeva, Larisa R.

    1994-12-01

    Pulsed photothermal radiometry (PPTR) of tissue based on the analysis of thermal radiation kinetics measured from tissue at laser heating is an effective method of laser-tissue interaction investigation. The processes of destruction under laser radiation action (coagulation, fusion and welding), which are characterized by definite dynamics of temperature in the region of laser heating, have been studied. The amplitude and kinetics of the thermal signal registered by PPTR technique depend on space and temporal temperature changes in the zone of heating, which is conditioned by the regime of laser action and internal processes in tissue. In the present study the investigation of thermal tissue destruction under action of high-power pulsed CO2 and YAG:Er-laser radiation has been carried out using PPTR. Soft and hard tissues have been examined. The nonlinear dependencies of thermal emission kinetics, the thermal signal amplitude, and the integral absorption on laser energy density are presented and discussed. We represent PPTR as a technique which can be used for the definition of the destruction threshold and for the regulation of laser action on tissue. PPTR method has been applied in clinics with the aim of more accurate definition of CO2 pulsed medical laser radiation dose for treatment of patients with different dermatological diseases.

  3. Thermal mapping of the lunar surface. [using infrared radiometry

    NASA Technical Reports Server (NTRS)

    Raine, W. L.

    1973-01-01

    A program of lunar infrared radiometry which uses large area scanning is described, and procedures for atmospheric attenuation correction and data reduction to temperature by relative radiometry are outlined. Flow charts of the computer data reduction program are shown which contain the astrometric analysis from ephemeral data. The scan data, taken on 10 evenings in 1971 and 1972 in the 10 to 12 micron window, are presented as isothermal contour maps of the lunar disc. More than 160 areas of anomalous thermal emission were found in the lunar darkside data. Eclipse cooling curves, measured in the same wavelength band for 7 lunar regions during the eclipse of February 10, 1971, are also presented. Errors of the scan and eclipse data were calculated from accuracy estimates of the parameters.

  4. A young region on Enceladus revealed by 2 cm radiometry?

    NASA Astrophysics Data System (ADS)

    Ries, P.; Janssen, M.

    2014-04-01

    On 5 November 2011, the Cassini spacecraft had a flyby of Enceladus dedicated to its synthetic aperture radar (SAR) instrument. In the course of that flyby, approximately 80% of Enceladus' surface was also observed serendipitously with the microwave radiometer operating concurrently at 2.2 cm. The radiometry data is analyzed and shown to drop sharply in the leading hemisphere's smooth terrain. This drop is also demonstrated in a series of unresolved distant radiometry measurements spread out over the ten years of the Cassini mission. However, the anomaly is absent from distant unresolved RADAR measurements and not visible in SAR imaging. The anomaly is most likely caused by a young surface (<100MYr in age) which has not yet been processed by micrometeoroid impacts below the electromagnetic skin depth (3 m).

  5. Detection of subclinical synovial inflammation by microwave radiometry.

    PubMed

    Zampeli, Evangelia; Raftakis, Ioannis; Michelongona, Archontoula; Nikolaou, Chara; Elezoglou, Antonia; Toutouzas, Konstantinos; Siores, Elias; Sfikakis, Petros P

    2013-01-01

    Microwave Radiometry is a non-invasive method which determines within seconds the in vivo temperature of internal tissues at a depth of 3-7 cm with an accuracy of ±0.2°C. In this proof-of-concept study, we tested the hypothesis that, in absence of relevant clinical signs, increased local temperature detected by microwave radiometry reflects subclinical synovial inflammation, using ultrasound as reference method. Knees of healthy controls, subjects with recent knee trauma and symptom-free patients with rheumatoid arthritis (RA) or osteoarthritis were examined by placing the microwave radiometry sensor, a) at the upper one third of the anterior surface of the thigh (control-point), and b) over the suprapatellar recess. Ultrasound was performed immediately after and the possible presence of fluid and/or synovitis was correlated with microwave radiometry findings. In 30 healthy and 10 injured knees the temperature was always lower than thigh (32.3±1.1 and 31.8±1.4 versus 34.1±0.9 and 33.6±1.2°C with a difference (ΔΤ) of -1.8±0.2 and -1.9±0.4°C respectively). Of 40 RA and 20 osteoarthritis knees examined, ultrasound findings indicative of subclinical inflammation (fluid effusion and/or Doppler signal) were found in 24 and 12, respectively, in which the temperature was higher than healthy knees and ΔΤ was lower (-0.9±0.7 in RA and -1.0±0.5 in osteoarthritis versus -1.8±0.2°C, p<0.001). The 5 RA knees with power Doppler findings indicative of grade 2 inflammation had a ΔΤ 3 times lower compared to healthy (-0.6±0.6, p = 0.007), whereas the 9 RA and the 7 osteoarthritis knees with additionally fluid effusion, had even lower ΔΤ (-0.4±0.7, p<0.001). Using a safe, rapid and easy-to-perform method, such as microwave radiometry, thermal changes within the knee joint may reflect non-clinically apparent joint inflammation. Refinement of this method, including production of sensors for small joints, could result to the development of the ideal objective

  6. Detection of Subclinical Synovial Inflammation by Microwave Radiometry

    PubMed Central

    Zampeli, Evangelia; Raftakis, Ioannis; Michelongona, Archontoula; Nikolaou, Chara; Elezoglou, Antonia; Toutouzas, Konstantinos; Siores, Elias; Sfikakis, Petros P.

    2013-01-01

    Objective Microwave Radiometry is a non-invasive method which determines within seconds the in vivo temperature of internal tissues at a depth of 3–7 cm with an accuracy of ±0.2°C. In this proof-of-concept study, we tested the hypothesis that, in absence of relevant clinical signs, increased local temperature detected by microwave radiometry reflects subclinical synovial inflammation, using ultrasound as reference method. Methods Knees of healthy controls, subjects with recent knee trauma and symptom-free patients with rheumatoid arthritis (RA) or osteoarthritis were examined by placing the microwave radiometry sensor, a) at the upper one third of the anterior surface of the thigh (control-point), and b) over the suprapatellar recess. Ultrasound was performed immediately after and the possible presence of fluid and/or synovitis was correlated with microwave radiometry findings. Results In 30 healthy and 10 injured knees the temperature was always lower than thigh (32.3±1.1 and 31.8±1.4 versus 34.1±0.9 and 33.6±1.2°C with a difference (ΔΤ) of −1.8±0.2 and −1.9±0.4°C respectively). Of 40 RA and 20 osteoarthritis knees examined, ultrasound findings indicative of subclinical inflammation (fluid effusion and/or Doppler signal) were found in 24 and 12, respectively, in which the temperature was higher than healthy knees and ΔΤ was lower (−0.9±0.7 in RA and −1.0±0.5 in osteoarthritis versus −1.8±0.2°C, p<0.001). The 5 RA knees with power Doppler findings indicative of grade 2 inflammation had a ΔΤ 3 times lower compared to healthy (−0.6±0.6, p = 0.007), whereas the 9 RA and the 7 osteoarthritis knees with additionally fluid effusion, had even lower ΔΤ (−0.4±0.7, p<0.001). Conclusion Using a safe, rapid and easy-to-perform method, such as microwave radiometry, thermal changes within the knee joint may reflect non-clinically apparent joint inflammation. Refinement of this method, including production of sensors for small joints

  7. FOREWORD: New Developments and Applications in Optical Radiometry III

    NASA Astrophysics Data System (ADS)

    Fröhlich, C.

    1991-01-01

    The Proceedings published in this special issue of Metrologia are of New Developments and Applications in Optical Radiometry III, a meeting held in Davos, Switzerland, from 20 22 September 1990, organized by the Physikalisch-Meteorologisches Observatorium Davos (PMOD). As the title indicates it was the third in a series of such meetings: the first was organized by P V Foukal and took place in 1985 at Atmospheric and Environmental Research, Inc., in Cambridge, Mass., USA; the second was in 1988 at the National Physical Laboratory in Teddington, UK, organized by N P Fox and D H Nettleton. The idea of these meetings is to provide a platform to present and discuss developments and problem areas in optical radiometry among scientists working in different fields, such as metrology and solar radiometry. The choice of Davos as the meeting place was favoured by the fact that the 7th International Pyrheliometer Comparison (IPC VII) was held in autumn 1990 at PMOD. Although IPC is mainly technical and aimed at the worldwide standardization of pyrheliometers (radiometers used for solar measurements in meteorology), both communities—metrology and meteorology—have overlapping radiometric interests and a thorough exchange of ideas is important for the advancement of the field. The ever-increasing number of participants reveals the general interest in the topic and the next meeting, planned for spring 1992 in the United States, will be organized by B Guenther of the NASA/Goddard Space Flight Center, Greenbelt, Md, USA. The programme was divided into four sessions: Radiometric Scales, Radiometers and Quantum Detectors, Source Radiometry, and Solar Radiometry and Space Applications. A total of 47 papers were presented and most are published here. All contributions were refereed and cleared for publication by a board of four guest editors, one for each session: J L Gardner, L-P Boivin, D H Nettleton and B R Barkstrom. The pre-eminent value of the editors' work is manifested by

  8. Mesospheric H2O Concentrations Retrieved from SABER/TIMED Measurements

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Marshall, B. T.; Garcia-Comas, M.; Kutepov, A. A.; Lopez-Puertas, M.; Manuilova, R. O.; Yankovsky, V.A.; Goldberg, R. A.; Gordley, L. L.; Petelin, S.; Russell, J. M., III

    2008-01-01

    The SABER instrument on board the TIMED Satellite is a limb scanning infrared radiometer designed to measure temperature and minor constituent vertical profiles and energetics parameters in the mesosphere and lower thermosphere (MLT). The H2O concentrations are retrieved from 6.3 micron band radiances. The populations of H2O(v2) vibrational levels are in non-Local Thermodynamic Equilibrium (non-LTE) above approximately 55 km altitude and the interpretation of 6.3 micron radiance requires utilizing non-LTE H2O model that includes various energy exchange processes in the system of H2O vibrational levels coupled with O2, N2, and CO2 vibrational levels. We incorporated these processes including kinetics of O2/O3 photolysis products to our research non-LTE H2O model and applied it for the development and optimization of SABER operational model. The latter has been validated using simultaneous SCISAT1/ACE occultation measurements. This helped us to estimate CO2(020)-O2(X,v=I), O2(X,v=I)- H2O(010), and O2(X,v=1) O rates at mesopause temperatures that is critical for an adequate interpretation of non-LTE H2O radiances in the MLT. The first distributions of seasonal and meridional H2O concentrations retrieved from SABER 6.3 micron radiances applying an updated non-LTE H2O model are demonstrated and discussed.

  9. Mesospheric H2O Concentrations Retrieved from SABER/TIMED Measurements

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Marshall, B. T.; Garcia-Comas, M.; Kutepov, A. A.; Lopez-Puertas, M.; Manuilova, R. O.; Yankovsky, V.A.; Goldberg, R. A.; Gordley, L. L.; Petelin, S.; hide

    2008-01-01

    The SABER instrument on board the TIMED Satellite is a limb scanning infrared radiometer designed to measure temperature and minor constituent vertical profiles and energetics parameters in the mesosphere and lower thermosphere (MLT). The H2O concentrations are retrieved from 6.3 micron band radiances. The populations of H2O(v2) vibrational levels are in non-Local Thermodynamic Equilibrium (non-LTE) above approximately 55 km altitude and the interpretation of 6.3 micron radiance requires utilizing non-LTE H2O model that includes various energy exchange processes in the system of H2O vibrational levels coupled with O2, N2, and CO2 vibrational levels. We incorporated these processes including kinetics of O2/O3 photolysis products to our research non-LTE H2O model and applied it for the development and optimization of SABER operational model. The latter has been validated using simultaneous SCISAT1/ACE occultation measurements. This helped us to estimate CO2(020)-O2(X,v=I), O2(X,v=I)- H2O(010), and O2(X,v=1) O rates at mesopause temperatures that is critical for an adequate interpretation of non-LTE H2O radiances in the MLT. The first distributions of seasonal and meridional H2O concentrations retrieved from SABER 6.3 micron radiances applying an updated non-LTE H2O model are demonstrated and discussed.

  10. A comparison of ground-based hydroxyl airglow temperatures with SABER/TIMED measurements over 23° N, India

    NASA Astrophysics Data System (ADS)

    Parihar, Navin; Singh, Dupinder; Gurubaran, Subramanian

    2017-03-01

    Ground-based observations of OH (6, 2) Meinel band nightglow were carried out at Ranchi (23.3° N, 85.3° E), India, during January-March 2011, December 2011-May 2012 and December 2012-March 2013 using an all-sky imaging system. Near the mesopause, OH temperatures were derived from the OH (6, 2) Meinel band intensity information. A limited comparison of OH temperatures (TOH) with SABER/TIMED measurements in 30 cases was performed by defining almost coincident criterion of ±1.5° latitude-longitude and ±3 min of the ground-based observations. Using SABER OH 1.6 and 2.0 µm volume emission rate profiles as the weighing function, two sets of OH-equivalent temperature (T1. 6 and T2. 0 respectively) were estimated from its kinetic temperature profile for comparison with OH nightglow measurements. Overall, fair agreement existed between ground-based and SABER measurements in the majority of events within the limits of experimental errors. Overall, the mean value of OH-derived temperatures and SABER OH-equivalent temperatures were 197.3 ± 4.6, 192.0 ± 10.8 and 192.7 ± 10.3 K, and the ground-based temperatures were 4-5 K warmer than SABER values. A difference of 8 K or more is noted between two measurements when the peak of the OH emission layer lies in the vicinity of large temperature inversions. A comparison of OH temperatures derived using different sets of Einstein transition probabilities and SABER measurements was also performed; however, OH temperatures derived using Langhoff et al. (1986) transition probabilities were found to compare well.

  11. FOREWORD: New Developments and Applications in Optical Radiometry IV

    NASA Astrophysics Data System (ADS)

    Guenther, B.

    1993-01-01

    The Proceedings published in this special issue of Metrologia are from New Developments and Applications in Optical Radiometry IV, also known as the NEWRAD '92 Conference. The conference was held from 5 7 October 1992 in Baltimore, Maryland, USA, and was organized through the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center in Greenbelt, Maryland. The 1992 Conference was the fourth in a series of occasional international meetings held to integrate the activities of the space radiometry community with those of the laboratory metrology community. The location of Maryland was chosen to bring the meeting back to the hemisphere of the Americas where the first of the series was held. NASA/Goddard was chosen as the sponsoring organization for this meeting because of the number and diversity of space measurement programmes which are managed there, and because of its proximity to the United States National Institute of Standards and Technology. The general organization of the meeting included sessions on the Earth Observing System (which I chaired), the Shuttle Atlas I Mission and UV Calibrations (chaired by E Hilsenrath, NASA/Goddard), Cryogenic Radiometry (N Fox, NPL), Detector Radiometry (T Quinn, BIPM), Space-based Applications (J Metzdorf, PTB) and Ground-based Applications (C Cromer, NIST). Thirty-eight papers were presented orally, and poster sessions were also provided. Most of the presentations are represented in these Proceedings. The fifth meeting in this occasional series is scheduled for 19 21 September 1994 in Berlin. The Conference institutional host is the PTB, and the convener is Dr Joachim Fischer, Secretary. The success of the meeting derived principally from the individual contributions of the presenters and the interest and attention of all the participants. The success of these Proceedings is attributable to the individual authors, the guest editors and the referees of the papers. Each paper was subjected to a critical

  12. Vacuum ultraviolet radiometry with a stabilized hydrogen arc.

    NASA Technical Reports Server (NTRS)

    Ott, W. R.; Wiese, W. L.; Fieffe-Prevost, P.; Nakai, Y.

    1971-01-01

    Use of the spectral radiation emitted from a dense hydrogen plasma of at least 12,000 K, which is in local thermodynamic equilibrium (LTE), as a light source for vacuum UV radiometry. Its spectroscopic qualities are exactly known, and except for a few strongly Stark-broadened Lyman lines, its spectrum in the vacuum UV is essentially continuous. The calculated continuum output of this source for typical operating conditions is compared with the UV output of the tungsten strip lamp and the carbon arc.

  13. Kapitza thermal resistance studied by high-frequency photothermal radiometry

    SciTech Connect

    Horny, Nicolas; Chirtoc, Mihai; Hamaoui, Georges; Fleming, Austin; Ban, Heng

    2016-07-18

    Kapitza thermal resistance is determined using high-frequency photothermal radiometry (PTR) extended for modulation up to 10 MHz. Interfaces between 50 nm thick titanium coatings and silicon or stainless steel substrates are studied. In the used configuration, the PTR signal is not sensitive to the thermal conductivity of the film nor to its optical absorption coefficient, thus the Kapitza resistance is directly determined from single thermal parameter fits. Results of thermal resistances show the significant influence of the nature of the substrate, as well as of the presence of free electrons at the interface.

  14. Multiple Peaks in SABER Mesospheric OH Emission Altitude Profiles

    NASA Astrophysics Data System (ADS)

    Rozum, J. C.; Ware, G. A.; Baker, D. J.; Mlynczak, M. G.; Russell, J. M.

    2012-12-01

    Since January 2002, the SABER instrument aboard the TIMED satellite has been performing limb-scan measurements of the altitude distribution of the hydroxyl airglow. The majority of the SABER 1.6 μm and 2.0 μm OH volume emission rate (VER) profiles manifest a single peak at around 90 km, and are roughly gaussian in shape. However, a significant number (approximately 10% in nighttime) of these VER profiles have an irregular characteristic of multiple peaks that are comparable in brightness to the absolute maximum. The origin of these multiple peaks in SABER profiles is currently being studied. Single peak and irregular SABER OH VER profiles are compared with OH VER altitude curves obtained via theoretical vertical distribution models. In addition, we compare SABER profiles with OH VER altitude profiles obtained from rocket-borne radiometric experiments. The techniques of Liu and Shepherd's analysis of double-peaked emission profiles obtained by the Wind Imaging Interferometer (WINDII) using similar scan geometry are applied. The geographical distribution of the SABER nighttime multiple-peak VER profiles in the 1.6 μm and 2.0 μm channels is presented, as are the distributions of these profiles with respect to instrument-scan geometry parameters. It is noted that during the night, multiple peak profiles are more common at equatorial latitudes. A relationship has been found between the geographical distribution of two-peaked profiles and spatial orientation of the SABER instrument's viewing field.

  15. Water Vapor Remote Sensing Techniques: Radiometry and Solar Spectrometry

    NASA Astrophysics Data System (ADS)

    Somieski, A.; Buerki, B.; Cocard, M.; Geiger, A.; Kahle, H.-G.

    The high variability of atmospheric water vapor content plays an important role in space geodesy, climatology and meteorology. Water vapor has a strong influence on transatmospheric satellite signals, the Earth's climate and thus the weather forecasting. Several remote sensing techniques have been developed for the determination of inte- grated precipitable water vapor (IPWV). The Geodesy and Geodynamics Lab (GGL) utilizes the methods of Water Vapor Radiometry and Solar Spectrometry to quantify the amount of tropospheric water vapor and its temporal variations. The Water Vapor Radiometer (WVR) measures the radiation intensity of the atmosphere in a frequency band ranging from 20 to 32 GHz. The Solar Atmospheric MOnitoring Spectrome- ter (SAMOS) of GGL is designed for high-resolution measurements of water vapor absorption lines using solar radiation. In the framework of the ESCOMPTE (ExpÊrience sur Site pour COntraindre les Mod- Éles de Pollution atmosphÊrique et de Transport d'Emissions) field campaign these instruments have been operated near Marseille in 2001. They have aquired a long time series of integrated precipitable water vapor content (IPWV). The accuracy of IPWV measured by WVR and SAMOS is 1 kg/m2. Furthermore meteorological data from radiosondes were used to calculate the IPWV in order to provide comparisons with the results of WVR and SAMOS. The methods of Water Vapor Radiometry and So- lar Spectrometry will be discussed and first preliminary results retrieved from WVR, SAMOS and radiosondes during the ESCOMPTE field campaign will be presented.

  16. Nonintrusive noncontacting frequency-domain photothermal radiometry of caries

    NASA Astrophysics Data System (ADS)

    El-Sharkawy, Yasser H.; Abd-Elwahab, Bassam

    2010-04-01

    Among diffusion methods, photothermal radiometry (PTR) has the ability to penetrate and yield information about an opaque medium well beyond the range of conventional optical imaging. Owing to this ability, pulsed-laser PTR has been extensively used in turbid media such as biological tissues to study the sub-surface deposition of laser radiation, a task that may be difficult or impossible for many optical methods due to excessive scattering and absorption. In this paper considers the achievements of Pulsed Photothermal Radiometry using IR camera in the investigation of physical properties of biological materials and the diagnostics of the interaction of laser radiation with biological materials. A three-dimensional heat conduction formulation with the use of three-dimensional optical diffusion is developed to derive a turbid frequency-domain PTR model. The present photo-thermal model for frequency-domain PTR may prove useful for non-contact; non-invasive, in situ evaluate the depth profilometric imaging capabilities of FDPTR in monitoring carious and artificial subsurface lesions in human teeth.

  17. Absolute Temperature Monitoring Using RF Radiometry in the MRI Scanner

    PubMed Central

    El-Sharkawy, AbdEl-Monem M.; Sotiriadis, Paul P.; Bottomley, Paul A.; Atalar, Ergin

    2007-01-01

    Temperature detection using microwave radiometry has proven value for noninvasively measuring the absolute temperature of tissues inside the body. However, current clinical radiometers operate in the gigahertz range, which limits their depth of penetration. We have designed and built a noninvasive radiometer which operates at radio frequencies (64 MHz) with ∼100-kHz bandwidth, using an external RF loop coil as a thermal detector. The core of the radiometer is an accurate impedance measurement and automatic matching circuit of 0.05 Ω accuracy to compensate for any load variations. The radiometer permits temperature measurements with accuracy of ±0.1°K, over a tested physiological range of 28° C–40° C in saline phantoms whose electric properties match those of tissue. Because 1.5 T magnetic resonance imaging (MRI) scanners also operate at 64 MHz, we demonstrate the feasibility of integrating our radiometer with an MRI scanner to monitor RF power deposition and temperature dosimetry, obtaining coarse, spatially resolved, absolute thermal maps in the physiological range. We conclude that RF radiometry offers promise as a direct, noninvasive method of monitoring tissue heating during MRI studies and thereby providing an independent means of verifying patient-safe operation. Other potential applications include titration of hyper- and hypo-therapies. PMID:18026562

  18. Activity maps of gravity waves and triads derived from CHAMP and SABER data

    NASA Astrophysics Data System (ADS)

    Wernicke, Jeannette; Wüst, Sabine; Bittner, Michael

    Gravity waves have significant influence on the circulation and thermal structure of the atmo-sphere by transporting energy and momentum. One mechanism of coupling multiple altitudinal levels is the nonlinear wave-wave interaction called triad: two gravity waves can form a third one with different physical properties that can transport energy and momentum to areas far away from its origin. Due to the coarse spatial resolution most global circulation models are unable to resolve gravity waves. So, the effects have to be parameterised. In order to obtain a realistic representation it is important to expand the knowledge about the physical properties of gravity waves. Activity maps of gravity waves and triads are retrieved using satellite measurements from CHAMP (CHAllenging Minisatellite Payload) and SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) in an area (50° N, 10° W) to (43° N, 20° E) during the years 2001 to 2008. To retrieve these maps temperature profiles are analysed using the innovative detrending algo-rithm ECUS-D (Ensemble of CUbic Splines for Detrending) to separate background temper-ature and wave signatures. For gravity waves an activity index is calculated. The dominant wavelengths are estimated and searched for nonlinearities. To analyse different observational filters the measurements are compared to each other and to the results of campaign SIGMA-1 (Satellite Validation Impact of Gravity Waves in the Middle Atmosphere). SIGMA-1 is based mainly on radiosonde measurements with high temporal reso-lution at the observatory Hohenpeißenberg and additional synoptic measurements of radiosonde stations in the surrounding region.

  19. Hand-held radiometry: A set of notes developed for use at the Workshop of Hand-held radiometry

    NASA Technical Reports Server (NTRS)

    Jackson, R. D.; Pinter, P. J., Jr.; Reginato, R. J.; Idso, S. B. (Principal Investigator)

    1980-01-01

    A set of notes was developed to aid the beginner in hand-held radiometry. The electromagnetic spectrum is reviewed, and pertinent terms are defined. View areas of multiband radiometers are developed to show the areas of coincidence of adjacent bands. The amounts of plant cover seen by radiometers having different fields of view are described. Vegetation indices are derived and discussed. Response functions of several radiometers are shown and applied to spectrometer data taken over 12 wheat plots, to provide a comparison of instruments and bands within and among instruments. The calculation of solar time is reviewed and applied to the calculation of the local time of LANDSAT satellite overpasses for any particular location in the Northern Hemisphere. The use and misuse of hand-held infrared thermometers are discussed, and a procedure for photographic determination of plant cover is described. Some suggestions are offered concerning procedures to be followed when collecting hand-held spectral and thermal data. A list of references pertinent to hand-held radiometry is included.

  20. Climatology of terdiurnal tide in the mesosphere and lower thermosphere from TIMED SABER/TIDI, ground-based sodium lidar and NCAR TIME-GCM model

    NASA Astrophysics Data System (ADS)

    Yue, J.; Wu, Q.; Xu, J.; Liu, H.; Hagan, M. E.; Maute, A. I.; Yuan, T.; She, C.; Russell, J. M.

    2011-12-01

    In this paper, we investigate the nature of the terdiurnal tide (8 hour period) in the mesosphere and lower thermosphere (MLT), using the Colorado State University (CSU) temperature/wind sodium lidar data set (41N, 105W) (5 years, 2002 to 2006), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature and Doppler interferometer (TIDI) wind measurement for 7 years (2003 to 2009) both onboard of Thermosphere-ionosphere-Mesosphere-Energetics and Dynamics (TIMED) satellite, and the Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model runs (TIME-GCM). The seasonal variability and global structure of the terdiurnal tide will be provided. The amplitude of the terdiurnal tide depends heavily on season, latitude and altitude. For example, at northern mid-latitude, the maximum amplitudes in horizontal wind (20 m/s) and temperature (8 K) appear at 100 km in late winter from the lidar measurement, while it is the weakest in summer. SABER measurement reveals that the maximum of the terdiurnal tide temperature above 100 km occurs near equinox at mid-latitude. TIDI wind finds that the maximum amplitude in meridional wind at mid-latitude is before and after the solstice. The vertical wavelength of the terdiurnal tide will be estimated. The comparison between the TIME-GCM and the observations will enhance our understandings of the excitation, propagation and dissipation of the terdiurnal tide in the atmosphere. This will benefit our future study of the terdiurnal tidal impact in the thermosphere/ionosphere coupling.

  1. Comparison of OH and O2 rotational temperatures with SABER and SCIAMACHY temperatures in the context of the first NDMC measurement campaign

    NASA Astrophysics Data System (ADS)

    Wildner, Sabrina

    2010-05-01

    The Network for the Detection of Mesopause Change (NDMC) is a global program with the mission to promote international cooperation among research groups investigating the mesopause region (80-100km). From September 01 to October 31, 2009, the first global NDMC measurement campaign has been conducted. The main objective of this campaign was to investigate hemispheric asymmetries and planetary wave activities in the mesopause region. The intensity and temperature were derived from OH and O2 emissions using optical instruments such as spectrometers and photometers. Mesopause temperatures obtained from satellite observations with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the TIMED satellite and from satellite observations with the SCanning Imaging Absorption spectroMeter for the Atmospheric CHartograpY (SCIAMACHY) instrument on board the ENVISAT satellite are compared with the rotational temperatures obtained during the NDMC campaign by ground-based airglow spectrometers. This campaign dataset provides an excellent opportunity for the intercomparison of rotational temperatures obtained with a large ensemble of ground based airglow instruments at different locations with satellite based measurements. Data for intercomparison are chosen following equal miss time and miss distance criteria for every instrument location. Airglow-equivalent temperatures are derived from the satellite temperature profiles by applying an appropriate weighting function. The differences at each location between temperatures from SABER, SCIAMACHY and corresponding ground based NDMC instruments are presented.

  2. Directional Radiometry and Radiative Transfer: the Convoluted Path From Centuries-old Phenomenology to Physical Optics

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael I.

    2014-01-01

    This Essay traces the centuries-long history of the phenomenological disciplines of directional radiometry and radiative transfer in turbid media, discusses their fundamental weaknesses, and outlines the convoluted process of their conversion into legitimate branches of physical optics.

  3. Feasibility Study of Radiometry for Airborne Detection of Aviation Hazards

    NASA Technical Reports Server (NTRS)

    Gimmestad, Gary G.; Papanicolopoulos, Chris D.; Richards, Mark A.; Sherman, Donald L.; West, Leanne L.; Johnson, James W. (Technical Monitor)

    2001-01-01

    Radiometric sensors for aviation hazards have the potential for widespread and inexpensive deployment on aircraft. This report contains discussions of three aviation hazards - icing, turbulence, and volcanic ash - as well as candidate radiometric detection techniques for each hazard. Dual-polarization microwave radiometry is the only viable radiometric technique for detection of icing conditions, but more research will be required to assess its usefulness to the aviation community. Passive infrared techniques are being developed for detection of turbulence and volcanic ash by researchers in this country and also in Australia. Further investigation of the infrared airborne radiometric hazard detection approaches will also be required in order to develop reliable detection/discrimination techniques. This report includes a description of a commercial hyperspectral imager for investigating the infrared detection techniques for turbulence and volcanic ash.

  4. Fiscal Year 2005 Solar Radiometry and Metrology Task Accomplishments

    SciTech Connect

    Myers, D.; Andreas, A.; Reda, I.; Gotseff, P.; Wilcox, S.; Stoffel, T.; Anderberg, M.; Kay, B.; Bowen, A.

    2005-11-01

    The National Renewable Energy Laboratory (NREL) Solar Radiometry and Metrology task provides traceable optical radiometric calibrations and measurements to photovoltaic (PV) researchers and the PV industry. Traceability of NREL solar radiometer calibrations to the World Radiometric Reference (WRR) was accomplished during Pyrheliometer Comparison at NREL in October 2004. Ten spectral and more than 200 broadband radiometers for solar measurements were calibrated this year. We measured detailed spectral distributions of the NREL and PV industry Pulsed Solar Simulators and are analyzing the influence of environmental variables on radiometer uncertainty. New systems for indoor and outdoor solar radiometer calibrations and ultraviolet (UV) spectral measurements and UV radiometer calibrations were purchased and tested. Optical metrology functions support the NREL Measurement and Characterization Task effort for ISO 17025 accreditation of NREL Solar Reference Cell Calibrations and have been integrated into the NREL quality system and audited for ISO17025 compliance.

  5. High-resolution submillimeter-wave radiometry of supersonic flow

    NASA Technical Reports Server (NTRS)

    Dionne, G. F.; Weiss, J. A.; Fitzgerald, J. F.; Fetterman, H. R.; Litvak, M. M.

    1983-01-01

    The recent development of a high-resolution submillimeter-wave heterodyne radiometer has made possible the first measurements of H2O molecule rotational line excitation temperatures and detailed profiles in supersonic flow. Absorption signals were measured across the flow for the 2/11/ from 2//02/ (752 GHz) para-H2O rotational transition against a hot background. These signals decrease downstream owing to the volume expansion of the gas away from the sonic nozle exit in the high-vacuum chamber. Radiative transfer calculations based on the large-velocity-gradient approximation and multilevel statistical equilibrium agree with these results and with the measured spectral line shapes. The data reveal nearly isentropic gas expansion and cooling. These studies have shown that submillimeter-wave heterodyne radiometry can be useful for remote sensing of supersonic flow with low mass flux, provided the signal transmission is through a dry or thin atmosphere.

  6. Photothermal Radiometry and Diffuse Reflectance Analysis of Thermally Treated Bones

    NASA Astrophysics Data System (ADS)

    Trujillo, S.; Martínez-Torres, P.; Quintana, P.; Alvarado-Gil, Juan Jose

    2010-05-01

    Different fields such as archaeology, biomedicine, forensic science, and pathology involve the analysis of burned bones. In this work, the effects of successive thermal treatments on pig long bones, measured by photothermal radiometry and diffuse reflectance are reported. Measurements were complemented by X-ray diffraction and infrared spectroscopy. Samples were thermally treated for 1 h within the range of 25 °C to 350 °C. The thermal diffusivity and reflectance increase in the low-temperature range, reaching a maximum around 125 °C and decaying at higher temperatures. These results are the consequence of complex modifications occurring in the inorganic and organic bone structure. For lower temperatures dehydration, dehydroxilation, and carbonate loss processes are dominant, followed by collagen denaturing and decompositions, which have an influence on the bone microstructure.

  7. Refined treatment of single-edge diffraction effects in radiometry.

    PubMed

    Shirley, Eric L

    2016-08-01

    This work treats diffraction corrections in radiometry for cases of point and extended sources in cylindrically symmetrical three-element systems. It considers diffraction effects for spectral power and total power in cases of Planck sources. It improves upon an earlier work by the author by giving a simpler rendering of leading terms in asymptotic expansions for diffraction effects and reliable estimates for the remainders. This work also demonstrates a framework for accelerating the treatment of extended sources and simplifying the calculation of diffraction effects over a range of wavelengths. This is especially important in the short-wavelength region, where dense sampling of wavelength values is in principle necessitated by the rapidly oscillatory behavior of diffraction effects as a function of wavelength. We demonstrate the methodology's efficacy in two radiometric applications.

  8. Target contrast considerations in millimeter wave radiometry for airborne navigation

    NASA Technical Reports Server (NTRS)

    Mayer, A.

    1971-01-01

    Target signal requirements for aircraft navigation systems that use radiometric receivers which map thermally emitted power radiated by terrain or power radiated by ground-based beacons are discussed. For selected millimeter wavelength bands, microwaves suffer relatively little degradation by absorption or scattering on passage through the atmosphere, despite extreme weather variations. Interest centers on 8-millimeter waves because of component availability, portability (small size), high image resolution, and all-weather capability at this wavelength. The idea of radiometric airborne navigation is introduced. Elements of radiometry, terrain radiation, and atmospheric transmission characteristics are reviewed. Data pertaining to these elements at 8 mm wavelength are collected. Calculation of radiometric contrasts is discussed for some simple models of terrain targets.

  9. SABER: The Searchable Annotated Bibliography of Education Research in Astronomy

    NASA Astrophysics Data System (ADS)

    Bruning, David H.; Bailey, J. M.; Brissenden, G.

    2006-12-01

    Starting a new research project in astronomy education is hard because the literature is scattered throughout many journals. Relevant astronomy education research may be in psychology journals, science education journals, physics education journals, or even in science journals themselves. Tracking the vast realm of literature is difficult, especially since libraries do not carry many of these journals and related abstracting services. SABER is an online resource (http://astronomy.uwp.edu/saber/) that was started in 2001 specifically to reduce this “scatter” by compiling into one place an annotated bibliography of relevant education research articles. The database now includes more than 150 articles specifically addressing astronomy education research. Visit SABER and see what it can do for you.

  10. SABER: The Searchable Annotated Bibliography of Education Research in Astronomy

    NASA Astrophysics Data System (ADS)

    Bruning, David; Bailey, Janelle M.; Brissenden, Gina

    Starting a new research project can be a challenge, but especially so in education research because the literature is scattered throughout many journals. Relevant astronomy education research may be in psychology journals, science education journals, physics education journals, or even in science journals. Tracking the vast realm of literature is difficult, especially because libraries frequently do not subscribe to many of the relevant journals and abstracting services. The Searchable Annotated Bibliography of Education Research (SABER) is an online resource that was started to service the needs of the astronomy education community, specifically to reduce this "scatter" by compiling an annotated bibliography of education research articles in one electronic location. Although SABER started in 2001, the database has a new URL—http://astronom- y.uwp.edu/saber/—and has recently undergone a major update.

  11. Detecting volcanism on Titan and Venus with microwave radiometry

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.; Le Gall, Alice; Janssen, Michael A.

    2016-05-01

    The detection by spaceborne instrumentation of infrared thermal emission from volcanic eruptions is well-established on Earth, but is challenged on Venus and Titan by their optically-thick atmospheres. Microwave radiometry in principle offers the ability to detect emission from surface thermal anomalies on these worlds due to greater atmospheric transparency: microwaves also offer the prospect of sensing the shallow subsurface and thus may detect warmth from lava flows for longer than surface infrared emission. However, satellite microwave instruments typically have low spatial resolution (10s of km) so volcanic heat is diluted in the wide instrument footprint. We examine the prospects for the detection of volcanic deposits by microwave, given likely planetary eruption rates and lava flow deposit geometries, using Mt Etna as a template. Nondetection of prominent hotspots in Cassini data may imply that the resurfacing rate is lower than ∼2 km3/yr, five times smaller than the expression of an Earth-like fraction of geothermal heat flow as latent heat in extrusive volcanism.

  12. Quantum Tunneling Sb-Heterostructures for Millimeter Wave Radiometry

    NASA Astrophysics Data System (ADS)

    Schulman, Joel N.

    2003-03-01

    Imaging in the millimeter wavelength range has been making rapid progress as high speed electronics increase in frequency. Applications include viewing through adverse visibility conditions (fog, smoke, dust, precipitation) and also the relative transparency of clothing (concealed-weapons-detection) and some building materials (through-the-wall-detection). Atmospheric radiometry (climate assessment and weather prediction) already depend heavily on this wavelength range. Astronomical applications include incorporation in instruments for cosmic microwave background detection. An important ingredient is a diode that "rectifies" in a special way. It must convert input power, i.e., voltage squared, into a DC voltage output -- a "square-law" detector. We have recently found that quantum tunneling through an InAs/AlSb/GaAlSb heterostructure system provides the ideal physical mechanism for this purpose.1,2 We will present our results to date, demonstrating how a close coupling of semiconductor quantum tunneling theory with electrical engineering know-how have brought an "exotic" quantum phenomon to practical and economic application. 1. "Sb-heterostructure interband backward diodes" J.N. Schulman and D.H. Chow. IEEE Electron Device Letters 21, 353-355 (2000). 2. "High-Performance Antimonide-Based Heterostructure Backward Diodes for Millimeter-wave Detection" P. Fay, J. N. Schulman, S. Thomas III, D. H. Chow, Y. K. Boegeman, and K. S. Holabird, IEEE Electron Device Letters 23, 585-587 (2002).

  13. Accurate Radiometry from Space: An Essential Tool for Climate Studies

    NASA Technical Reports Server (NTRS)

    Fox, Nigel; Kaiser-Weiss, Andrea; Schmutz, Werner; Thome, Kurtis; Young, Dave; Wielicki, Bruce; Winkler, Rainer; Woolliams, Emma

    2011-01-01

    The Earth s climate is undoubtedly changing; however, the time scale, consequences and causal attribution remain the subject of significant debate and uncertainty. Detection of subtle indicators from a background of natural variability requires measurements over a time base of decades. This places severe demands on the instrumentation used, requiring measurements of sufficient accuracy and sensitivity that can allow reliable judgements to be made decades apart. The International System of Units (SI) and the network of National Metrology Institutes were developed to address such requirements. However, ensuring and maintaining SI traceability of sufficient accuracy in instruments orbiting the Earth presents a significant new challenge to the metrology community. This paper highlights some key measurands and applications driving the uncertainty demand of the climate community in the solar reflective domain, e.g. solar irradiances and reflectances/radiances of the Earth. It discusses how meeting these uncertainties facilitate significant improvement in the forecasting abilities of climate models. After discussing the current state of the art, it describes a new satellite mission, called TRUTHS, which enables, for the first time, high-accuracy SI traceability to be established in orbit. The direct use of a primary standard and replication of the terrestrial traceability chain extends the SI into space, in effect realizing a metrology laboratory in space . Keywords: climate change; Earth observation; satellites; radiometry; solar irradiance

  14. Tower-Perturbation Measurements in Above-Water Radiometry

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Zibordi, Giuseppe; Berthon, Jean-Francois; DAlimonte, Davide; vanderLinde, Dirk; Brown, James W.

    2003-01-01

    This report documents the scientific activities which took place during June 2001 and June 2002 on the Acqua Alta Oceanographic Tower (AAOT) in the northern Adriatic Sea. The primary objective of these field campaigns was to quantify the effect of platform perturbations (principally reflections of sunlight onto the sea surface) on above-water measurements of water-leaving radiances. The deployment goals documented in this report were to: a) collect an extensive and simultaneous set of above- and in-water optical measurements under predominantly clear-sky conditions; b) establish the vertical properties of the water column using a variety of ancillary measurements, many of which were taken coincidently with the optical measurements; and c) determine the bulk properties of the environment using a diversity of atmospheric, biogeochemical, and meteorological techniques. A preliminary assessment of the data collected during the two field campaigns shows the perturbation in above-water radiometry caused by a large offshore structure is very similar to that caused by a large research vessel.

  15. Study of blood flow sensing with microwave radiometry

    NASA Technical Reports Server (NTRS)

    Porter, R. A.; Wentz, F. J., III

    1973-01-01

    A study and experimental investigation has been performed to determine the feasibility of measuring regional blood flow and volume in man by means of microwave radiometry. An indication was expected of regional blood flow from measurement of surface and subsurface temperatures with a sensitive radiometer. Following theoretical modeling of biological tissue, to determine the optimum operating frequency for adequate sensing depth, a sensitive microwave radiometer was designed for operation at 793 MHz. A temperature sensitivity of of 0.06 K rms was realized in this equipment. Measurements performed on phantom tissue models, consisting of beef fat and lean beefsteak showed that the radiometer was capable of sensing temperatures from a depth between 3.8 and 5.1 cm. Radiometric and thermodynamic temperature measurements were also performed on the hind thighs of large dogs. These showed that the radiometer could sense subsurface temperatures from a depth of, at least, 1.3 cm. Delays caused by externally-generated RF interference, coupled with the lack of reliable blood flow measurement equipment, prevented correlation of radiometer readings with reginal blood flow. For the same reasons, it was not possible to extend the radiometric observations to human subjects.

  16. Possible Influence of Aperture Heating on VIRGO Radiometry on SOHO

    NASA Astrophysics Data System (ADS)

    Frohlich, C.

    2010-12-01

    The early increase, first observed by the PMO6V radiometer on VIRGO/SOHO, indicates that aperture heating may be a problem for solar radiometry, not only in space, but also on ground. Heating of the precision aperture in front of the receiver cavity increases the irradiance in proportion to the incoming solar radiation and the emitted radiation from the aperture is added to the irradiance measured. Similar effects are also observed in ACRIMs and the HF on NIMBUS-7 and seem to be inherent to radiometers with the precision aperture directly in front of the cavity and the view limiting one at some distance in front. With this arrangement the precision aperture is illuminated during the measurement phase only and the measured irradiance increased accordingly. In TIM on SORCE the precision aperture is in front of the radiometer and the cavity entrance area determines the view angle. This avoids the influence of aperture heating and it may explain - at least part of - the fact that TIM measures lower values than the classical radiometers. Experimentally this effect is very difficult to determine directly and the result of thermal-model calculations and air-vacuum ratios with different amount of aperture heating are used to learn more about the magnitude of this effect. An estimate of this effect for the PMO6V/VIRGO instrument is presented.

  17. Volatile organic compound monitoring by photo acoustic radiometry

    SciTech Connect

    Sollid, J.E.; Trujillo, V.L.; Limback, S.P.; Woloshun, K.A.

    1995-12-01

    Two methods for sampling and analyzing volatile organics in subsurface pore gas were developed for use at the Hazardous Waste Disposal Site at Los Alamos National Laboratory. One is Thermal Desorption Gas Chromatography Mass Spectrometry (TDGCMS), the other is Photoacoustic Radiometry (PAR). Presented here are two years worth of experience and lessons learned as both techniques matured. The sampling technique is equally as important as the analysis method. PAR is a nondispersive infrared technique utilizing band pass filters in the region from 1 to 15 {mu}m. A commercial instrument, the Model 1302 Multigas Analyzer, made by Bruel and Kjaer, was adapted for field use. To use the PAR there must be some a priori knowledge of the constellation of analytes to be measured. The TDGCMS method is sensitive to 50 analytes. Hence TDGCMS is used in an initial survey of the site to determine what compounds are present and at what concentration. Once the major constituents of the soil-gas vapor plume are known the PAR can be configured to monitor for the five analytes of most interest. The PAR can analyse a sample in minutes, while in the field. The PAR is also quite precise in controlled situations.

  18. The Traceable Radiometry Underpinning Terrestrial and Helio Studies (TRUTHS) mission

    NASA Astrophysics Data System (ADS)

    Green, Paul D.; Fox, Nigel P.; Lobb, Daniel; Friend, Jonathan

    2015-10-01

    TRUTHS (Traceable Radiometry Underpinning Terrestrial- and Helio-Studies) is a proposed small satellite mission to enable a space-based climate observing system capable of delivering data of the quality needed to provide the information needed by policy makers to make robust mitigation and adaptation decisions. This is achieved by embedding trust and confidence in the data and derived information (tied to international standards) from both its own measurements and by upgrading the performance and interoperability of other EO platforms, such as the Sentinels by in-flight reference calibration. TRUTHS would provide measurements of incoming (total and spectrally resolved) and global reflected spectrally and spatially (50 m) solar radiation at the 0.3% uncertainty level. These fundamental climate data products can be convolved into the building blocks for many ECVs and EO applications as envisaged by the 2015 ESA science strategy; in a cost effective manner. We describe the scientific drivers for the TRUTHS mission and how the requirements for the climate benchmarking and cross-calibration reference sensor are both complementary and simply implemented, with a small additional complexity on top of heritage calibration schemes. The calibration scheme components and the route to SI-traceable Earth-reflected solar spectral radiance and solar spectral irradiance are described.

  19. Non-invasive thermometry with multi-frequency microwave radiometry.

    PubMed

    Mizushina, S; Shimizu, T; Sugiura, T

    1992-01-01

    The present status of the development of a non-invasive thermometer based on microwave radiometry at our laboratory is reported. We have developed a model fitting technique combined with a Monte Carlo technique to retrieve temperature-depth profiles from multi (4-6)-frequency-band microwave radiometric data along with confidence intervals (2-sigma) of tissue temperatures as a function of depth. In order to make the radiometric technique compatible with the heating, brightness temperatures are measured through a 1 cm thick water bolus. Results of phantom experiments are presented to demonstrate the above capabilities of the method. Numerical simulation studies have shown that 2-sigma intervals would be 1.0 K or less over a 0-4 cm range and 1.4 K at 5 cm from the surface with using a six-band, 1-5 GHz radiometer having brightness temperature resolution of 0.03 K (3 s integration time). The six-band instrument is currently being assembled at our laboratory.

  20. Accurate Radiometry from Space: An Essential Tool for Climate Studies

    NASA Technical Reports Server (NTRS)

    Fox, Nigel; Kaiser-Weiss, Andrea; Schmutz, Werner; Thome, Kurtis; Young, Dave; Wielicki, Bruce; Winkler, Rainer; Woolliams, Emma

    2011-01-01

    The Earth s climate is undoubtedly changing; however, the time scale, consequences and causal attribution remain the subject of significant debate and uncertainty. Detection of subtle indicators from a background of natural variability requires measurements over a time base of decades. This places severe demands on the instrumentation used, requiring measurements of sufficient accuracy and sensitivity that can allow reliable judgements to be made decades apart. The International System of Units (SI) and the network of National Metrology Institutes were developed to address such requirements. However, ensuring and maintaining SI traceability of sufficient accuracy in instruments orbiting the Earth presents a significant new challenge to the metrology community. This paper highlights some key measurands and applications driving the uncertainty demand of the climate community in the solar reflective domain, e.g. solar irradiances and reflectances/radiances of the Earth. It discusses how meeting these uncertainties facilitate significant improvement in the forecasting abilities of climate models. After discussing the current state of the art, it describes a new satellite mission, called TRUTHS, which enables, for the first time, high-accuracy SI traceability to be established in orbit. The direct use of a primary standard and replication of the terrestrial traceability chain extends the SI into space, in effect realizing a metrology laboratory in space . Keywords: climate change; Earth observation; satellites; radiometry; solar irradiance

  1. History of Solar Radiometry and the World Radiometric Reference

    NASA Astrophysics Data System (ADS)

    Fröhlich, C.

    1991-01-01

    The history of solar radiometry since the first pyrheliometer of Pouillet is presented. After the invention of the Ångström and the Smithsonian pyrheliometers around the turn of this century two different "scales" were in use. Comparisons with absolute cavity radiometers developed in America and Europe have been performed since about 1910 which show remarkably accurate measurements in terms of the SI units. However, these results have never been accepted and several rules have been established to reference radiation measurements in the meteorological community and to remedy the unsatisfactory fact of having different "scales". Unfortunately none of these rules led to a reference close to the SI units of irradiance, confusing the issue even more. With the advent of modern absolute radiometers in the late 1960s the situation improved and led to the definition of the World Radiometric Reference in use by the meteorological community since 1981. This reference has an estimated accuracy of 0,3% and guarantees the worldwide homogeneity of radiation measurements within 0,1% precision.

  2. RFI Risk Reduction Activities Using New Goddard Digital Radiometry Capabilities

    NASA Technical Reports Server (NTRS)

    Bradley, Damon; Kim, Ed; Young, Peter; Miles, Lynn; Wong, Mark; Morris, Joel

    2012-01-01

    The Goddard Radio-Frequency Explorer (GREX) is the latest fast-sampling radiometer digital back-end processor that will be used for radiometry and radio-frequency interference (RFI) surveying at Goddard Space Flight Center. The system is compact and deployable, with a mass of about 40 kilograms. It is intended to be flown on aircraft. GREX is compatible with almost any aircraft, including P-3, twin otter, C-23, C-130, G3, and G5 types. At a minimum, the system can function as a clone of the Soil Moisture Active Passive (SMAP) ground-based development unit [1], or can be a completely independent system that is interfaced to any radiometer, provided that frequency shifting to GREX's intermediate frequency is performed prior to sampling. If the radiometer RF is less than 200MHz, then the band can be sampled and acquired directly by the system. A key feature of GREX is its ability to simultaneously sample two polarization channels simultaneously at up to 400MSPS, 14-bit resolution each. The sampled signals can be recorded continuously to a 23 TB solid-state RAID storage array. Data captures can be analyzed offline using the supercomputing facilities at Goddard Space Flight Center. In addition, various Field Programmable Gate Array (FPGA) - amenable radiometer signal processing and RFI detection algorithms can be implemented directly on the GREX system because it includes a high-capacity Xilinx Virtex-5 FPGA prototyping system that is user customizable.

  3. Theory of noncontact point thermal sensing by fiber-optic radiometry.

    PubMed

    Zur, A; Katzir, A

    1992-01-01

    This paper formulates a theory of noncontact point thermal sensing by fiber-optic radiometry. This theory covers the field of mid- and far-infrared fibers that are suitable for low-temperature radiometry. However, new problems arise in the infrared range, the emission of thermal radiation from the fiber itself due to infrared absorption introduces perturbations into the radiometry, and this must be taken into consideration. The model presented is based on three-dimensional optical geometry of bounded and tunneling skew rays and yields an analytical expression for the inclination and the skewness angle distribution of the guided power collected by the fiber from various layers of a thermal body. The effective field of view, the surface resolution, and the temperature resolution of fiber-optic radiometry are discussed. Thermal sensing by direct coupling is shown to have an advantage over the coupling of a focusing lens located behind the fiber tip. A formulation of fiber emissivity is presented that quantifies the suppression of radiometric perturbations in fiber-optic thermal sensing. Bulk and surface absorption in the fiber core and cladding absorption are all taken into consideration deriving emissivity. Combining the transmissivity and emissivity of the fiber, we propose a measurable criterion, a figure of merit, for fiber-optic radiometry.

  4. Global and Seasonal Visualization of Mesospheric OH Emissions from SABER

    NASA Astrophysics Data System (ADS)

    Baker, D. J.; Reese, K. B.; Fielding, R. L.; Mlynczak, M. G.; Russell, J. M.

    2005-05-01

    On December 7, 2001, SABER, a cooled multichannel radiometer, was launched aboard the NASA TIMED satellite into a 625 km orbit and is functioning as planned. In January of 2002 the SABER instrument began returning airglow limb scan measurements from around the globe. Data now available include 65% of the year 2002, 75% of the year 2003, and nearly 100% of the year 2004. Experimental data were taken from SABER for two of SABER's ten radiometric channels centered at λ = 1.6 μm and λ = 2.06 μm as a measure of different levels of OH excitation. The objective of the research analysis reported in this paper is the optimal display of the three-dimensional dynamics of the global OH infrared airglow. Volume emission rate (VER) as a function of latitude, longitude, altitude, and time was computed. An investigation into seasonal effects on the global distribution of the OH airglow was performed for expanded 2004 data. Interpolation methods for optimizing geographic visualization were analyzed and compared. The Kriging method was found to have superior visualization and minimal mean squared error. The maximum VER often was found to be greater near the equator compared with values at high latitudes. Furthermore, the peak VER observed at the equator occurred at lower altitudes. In addition, seasonal differences between the two emission bands were explored and will be presented.

  5. Determination of combustion gas temperatures by infrared radiometry in sooting and nonsooting flames

    NASA Technical Reports Server (NTRS)

    Lyons, Valerie J.; Gracia-Salcedo, Carmen M.

    1989-01-01

    Flame temperatures in nonsooting and sooting environments were successfully measured by radiometry for pre-mixed propane-oxygen laminar flames stabilized on a water-cooled, porous sintered-bronze burner. The measured temperatures in the nonsooting flames were compared with fine-wire thermocouple measurements. The results show excellent agreement below 1700 K, and when the thermocouple measurements were corrected for radiation effects, the agreement was good for even higher temperatures. The benefits of radiometry are: (1) the flow is not disturbed by an intruding probe, (2) calibration is easily done using a blackbody source, and (3) measurements can be made even with soot present. The theory involved in the radiometry measurements and the energy balance calculations used to correct the thermocouple temperature measurements are discussed.

  6. Modulated IR radiometry for determining thermal properties and basic characteristics of titanium thin films

    SciTech Connect

    Apreutesei, Mihai; Lopes, Claudia; Vaz, Filipe; Macedo, Francisco; Borges, Joel

    2014-07-01

    Titanium thin films of different thicknesses were prepared by direct current magnetron sputtering to study modulated infrared (IR) radiometry as a tool for analyzing film thickness. Thickness was varied by regularly increasing the deposition time, keeping all the other deposition parameters constant. The influence of film thickness on morphological, structural, and electrical properties of the titanium coatings also was investigated. The experimental results revealed a systematic grain growth with increasing film thickness, along with enhanced film crystallinity, which led to increased electrical conductivity. Using the results obtained by modulated IR radiometry, the thickness of each thin film was calculated. These thickness values were then compared with the coating thickness measurements obtained by scanning electron microscopy. The values confirmed the reliability of modulated IR radiometry as an analysis tool for thin films and coatings, and for determining thicknesses in the micrometer range, in particular.

  7. In Vivo Skin Solvent Penetration Measurements Using Opto-thermal Radiometry and Fingerprint Sensor

    NASA Astrophysics Data System (ADS)

    Xiao, Perry; Ou, X.; Ciortea, L. I.; Berg, E. P.; Imhof, R. E.

    2012-11-01

    This latest study on in vivo transdermal drug delivery by using opto-thermal radiometry and a capacitance-based fingerprint sensor is presented. A small amount of solvent was applied on the test sites of a volar forearm for a few minutes; opto-thermal measurements and fingerprint sensor measurements were performed both before the solvent application and periodically after. The results showed that, by selecting different detection wavelengths, opto-thermal radiometry could give the information either on the water concentration within skin or the solvent concentration within skin. The capacitance-based fingerprint sensor could clearly visualize solvent penetration through in vivo human skin, as it generated dynamic two-dimensional (2D) images of solvent distribution within skin, and combining with tape stripping, it was also possible to get solvent 3D depth profiles within skin. The correlation between opto-thermal transient emission radiometry and fingerprint sensor measurements was also evaluated.

  8. Radiometry simulation within the end-to-end simulation tool SENSOR

    NASA Astrophysics Data System (ADS)

    Wiest, Lorenz; Boerner, Anko

    2001-02-01

    12 An end-to-end simulation is a valuable tool for sensor system design, development, optimization, testing, and calibration. This contribution describes the radiometry module of the end-to-end simulation tool SENSOR. It features MODTRAN 4.0-based look up tables in conjunction with a cache-based multilinear interpolation algorithm to speed up radiometry calculations. It employs a linear reflectance parameterization to reduce look up table size, considers effects due to the topology of a digital elevation model (surface slope, sky view factor) and uses a reflectance class feature map to assign Lambertian and BRDF reflectance properties to the digital elevation model. The overall consistency of the radiometry part is demonstrated by good agreement between ATCOR 4-retrieved reflectance spectra of a simulated digital image cube and the original reflectance spectra used to simulate this image data cube.

  9. Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) Observations of Polar Winter Conditions in 2009; Comparisons with Years 2002-2008

    DTIC Science & Technology

    2011-02-03

    POLAR WINTER CONDITIONS IN 2009; COMPARISONS WITH YEARS 2002-2008 Peter P. Wintersteiner ARCON Corporation 260 Bear Hill Road Waltham...NUMBER ARCON Corporation 260 Bear Hill Rd. Waltham, MA 02451-1080 AFRL/RVBYM 9. SPONSORING... ARCON Corporation according to the provisions of contract #FA8718-04-C-0031. Much of this work was done during the fifth year in which it was in effect

  10. Microwave array applicator for radiometry-controlled superficial hyperthermia

    NASA Astrophysics Data System (ADS)

    Stauffer, Paul R.; Jacobsen, Svein; Neuman, Daniel

    2001-06-01

    Hyperthermia therapy has been shown clinically effective for a variety of skin diseases but current heating equipment is inadequate for most patients. This effort describes the design and performance of a flexible microstrip array applicator intended for heating large regions of tissue over contoured anatomy while at the same time monitoring temperature of the underlying tissue by non-invasive radiometric sensing of blackbody radiation from the heated volume. For this dual purpose applicator, an array of broadband Archimedean spiral receive antennas is integrated into an array of Dual Concentric Conductor heating apertures. Applicator heating uniformity is assessed with electric field scans in homogenous muscle phantoms and with measured temperature distributions in clinical treatments of chestwall recurrence of breast carcinoma. The data demonstrate precisely controlled heating out to the perimeter of large (40 x 13 cm2) multiaperture conformal array applicators. Capabilities of the radiometry system are assessed by correlation of brightness temperatures measured in phantom loads of known temperature distribution as seen through an intervening 5 mm thick water bolus at constant 40°C. The radiometer demonstrates excellent sensitivity and an accuracy of +0.1-0.45°C for temperature measurements up to 5 cm deep in phantom when using a one dimensional weighting function analysis and up to 6 independent 500 MHz bandwidths within the 1-4 GHz range. The data clearly indicate that both heating and radiometric thermometry are possible using the same thin and flexible printed circuit board microstrip array applicator. Once development is complete, this dual mode conformal array applicator with multiplexed radiometric display system should provide significantly improved uniformity and ease of heating large area superficial tissue disease.

  11. Io's heat flow from infrared radiometry: 1983-1993

    NASA Technical Reports Server (NTRS)

    Veeder, Glenn J.; Matson, Dennis L.; Johnson, Torrence V.; Blaney, Diana L.; Goguen, Jay D.

    1994-01-01

    We report the following results from a decade of infrared radiometry of Io: (1) The average global heat flow is more than approx. 2.5 W/sq.m, (2) large warm (less than or equal to 200 K) volcanic regions dominate the global heat flow, (3) smal high-temperature (greater than or = 300 K) 'hotspots' contribute little to the average heat flow, (4) thermal anomalies on the leading hemisphere contribute about half of the heat flow, (5) a substantial amount of heat is radiated during Io's night, (6) high-temperature (greater than or = 600 K) 'outbursts' occurred during approx. 4% of the nights we observed, (7) 'Loki' is the brightest, persistent, infrared emission feature, and (8) some excess emission is always present at the longitude of Loki, but its intensity and other characteristics change between apparitions. Observations of Io at M(4.8 micrometer), 8.7 micrometer, N(10 micrometer), and Q(20 micrometer) with the Infrared Telescope Facility presented here were collected during nine apparitions between 1983 and 1993. These measurements provide full longitudinal coveraged as well as an eclipse observation and the detection of two outbursts. Reflected sunlight, passive thermal emission, and radiation from thermal anomalies all contribute to the observed flux densities. We find that a new thermophysical model is required to match all the data. Two key elements of this model are (1) a 'thermal reservoir' unit which lowers daytime temperatures, and (2) the 'thermal pedestal effect' which shifts to shorter wavelengths the spectral emission due to the reradiation of solar energy absorbed by the thermal anomalies. The thermal anomalies are modeled with a total of 10 source components at five locations. Io's heat flow is the sum of the power from these components.

  12. Traceable radiometry underpinning terrestrial- and helio-studies (TRUTHS)

    NASA Astrophysics Data System (ADS)

    Fox, N.; Aiken, J.; Barnett, J. J.; Briottet, X.; Carvell, R.; Frohlich, C.; Groom, S. B.; Hagolle, O.; Haigh, J. D.; Kieffer, H. H.; Lean, J.; Pollock, D. B.; Quinn, T.; Sandford, M. C. W.; Schaepman, M.; Shine, K. P.; Schmutz, W. K.; Teillet, P. M.; Thome, K. J.; Verstraete, M. M.; Zalewski, E.

    2003-12-01

    The Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS) mission offers a novel approach to the provision of key scientific data with unprecedented radiometric accuracy for Earth Observation (EO) and solar studies, which will also establish well-calibrated reference targets/standards to support other EO missions. This paper presents the TRUTHS mission and its objectives. TRUTHS will be the first satellite mission to calibrate its EO instrumentation directly to Sl in orbit, overcoming the usual uncertainties associated with drifts of sensor gain and spectral shape by using an electrical rather than an optical standard as the basis of its calibration. The range of instruments flown as part of the payload will also provide accurate input data to improve atmospheric radiative transfer codes by anchoring boundary conditions, through simultaneous measurements of aerosols, particulates and radiances at various heights. Therefore, TRUTHS will significantly improve the performance and accuracy of EO missions with broad global or operational aims, as well as more dedicated missions. The provision of reference standards will also improve synergy between missions by reducing errors due to different calibration biases and offer cost reductions for future missions by reducing the demands for on-board calibration systems. Such improvements are important for the future success of strategies such as Global Monitoring for Environment and Security (GMES) and the implementation and monitoring of international treaties such as the Kyoto Protocol. TRUTHS will achieve these aims by measuring the geophysical variables of solar and lunar irradiance, together with both polarised and unpolarised spectral radiance of the Moon, Earth and its atmosphere. Published by Elsevier Ltd on behalf of COSPAR.

  13. Traceable Radiometry Underpinning Terrestrial - and Helio- Studies (TRUTHS)

    USGS Publications Warehouse

    Fox, N.; Aiken, J.; Barnett, J.J.; Briottet, X.; Carvell, R.; Frohlich, C.; Groom, S.B.; Hagolle, O.; Haigh, J.D.; Kieffer, H.H.; Lean, J.; Pollock, D.B.; Quinn, T.; Sandford, M.C.W.; Schaepman, M.; Shine, K.P.; Schmutz, W.K.; Teillet, P.M.; Thome, K.J.; Verstraete, M.M.; Zalewski, E.

    2003-01-01

    The Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS) mission offers a novel approach to the provision of key scientific data with unprecedented radiometric accuracy for Earth Observation (EO) and solar studies, which will also establish well-calibrated reference targets/standards to support other EO missions. This paper presents the TRUTHS mission and its objectives. TRUTHS will be the first satellite mission to calibrate its EO instrumentation directly to SI in orbit, overcoming the usual uncertainties associated with drifts of sensor gain and spectral shape by using an electrical rather than an optical standard as the basis of its calibration. The range of instruments flown as part of the payload will also provide accurate input data to improve atmospheric radiative transfer codes by anchoring boundary conditions, through simultaneous measurements of aerosols, particulates and radiances at various heights. Therefore, TRUTHS will significantly improve the performance and accuracy of EO missions with broad global or operational aims, as well as more dedicated missions. The provision of reference standards will also improve synergy between missions by reducing errors due to different calibration biases and offer cost reductions for future missions by reducing the demands for on-board calibration systems. Such improvements are important for the future success of strategies such as Global Monitoring for Environment and Security (GMES) and the implementation and monitoring of international treaties such as the Kyoto Protocol. TRUTHS will achieve these aims by measuring the geophysical variables of solar and lunar irradiance, together with both polarised and unpolarised spectral radiance of the Moon, Earth and its atmosphere. Published by Elsevier Ltd of behalf of COSPAR.

  14. Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS)

    USGS Publications Warehouse

    Fox, N.; Aiken, J.; Barnett, J.J.; Briottet, X.; Carvell, R.; Frohlich, C.; Groom, S.B.; Hagolle, O.; Haigh, J.D.; Kieffer, H.H.; Lean, J.; Pollock, D.B.; Quinn, T.; Sandford, M.C.W.; Schaepman, M.; Shine, K.P.; Schmutz, W.K.; Teillet, P.M.; Thome, K.J.; Verstraete, M.M.; Zalewski, E.; ,

    2002-01-01

    The Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS) mission offers a novel approach to the provision of key scientific data with unprecedented radiometric accuracy for Earth Observation (EO) and solar studies, which will also establish well-calibrated reference targets/standards to support other EO missions. This paper will present the TRUTHS mission and its objectives. TRUTHS will be the first satellite mission to calibrate its instrumentation directly to SI in orbit, overcoming the usual uncertainties associated with drifts of sensor gain and spectral shape by using an electrical rather than an optical standard as the basis of its calibration. The range of instruments flown as part of the payload will also provide accurate input data to improve atmospheric radiative transfer codes by anchoring boundary conditions, through simultaneous measurements of aerosols, particulates and radiances at various heights. Therefore, TRUTHS will significantly improve the performance and accuracy of Earth observation missions with broad global or operational aims, as well as more dedicated missions. The provision of reference standards will also improve synergy between missions by reducing errors due to different calibration biases and offer cost reductions for future missions by reducing the demands for on-board calibration systems. Such improvements are important for the future success of strategies such as Global Monitoring for Environment and Security (GMES) and the implementation and monitoring of international treaties such as the Kyoto Protocol. TRUTHS will achieve these aims by measuring the geophysical variables of solar and lunar irradiance, together with both polarised and un-polarised spectral radiance of the Moon, and the Earth and its atmosphere.

  15. Low-latitude gravity wave variances in the mesosphere and lower thermosphere derived from SABER temperature observation and compared with model simulation of waves generated by deep tropical convection

    NASA Astrophysics Data System (ADS)

    Walterscheid, R. L.; Christensen, A. B.

    2016-10-01

    A portion of waves generated by deep convection have scales and amplitudes large enough to be detected by spaceborne instruments. We have analyzed temperature data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) satellite for subtidal-scale fluctuations. Filtering was applied both vertically and horizontally to extract wave variances. We have analyzed the altitude region between 70 and 130 km and focus on the variances at equatorial latitudes for the altitude region between 70 and 120 km as a function of season, local time intervals, geographical location, and altitude. We find significant variances where convection is particularly prolific (Intertropical Convergence Zone) and at altitudes where wave trapping is known to be favored (e.g., the lower thermospheric duct). The locations of significant variances persist from year to year. Standard deviations of a few tens of kelvins are found. We have also performed simulations of the response to deep tropical convection with a time-dependent, high-resolution fully compressible dynamical model. Our simulations give wave amplitudes that agree reasonably well with the observed amplitudes and show layering that is consistent with the observations. Our main finding is that significant variations seen in TIMED/SABER temperature data have a convective wave source and are concentrated in layers where thermal ducts occur.

  16. Detection of Vesicoureteral Reflux using Microwave Radiometry – System Characterization with Tissue Phantoms

    PubMed Central

    Maccarini, Paolo; De Luca, Valeria; Tognolatti, Piero; Bardati, Fernando; Snow, Brent; Stauffer, Paul

    2011-01-01

    Microwave (MW) radiometry is proposed for passive monitoring of kidney temperature to detect vesicoureteral reflux (VUR) of urine that is externally heated by a MW hyperthermia device and thereafter reflows from the bladder to kidneys during reflux. Here we characterize in tissue-mimicking phantoms the performance of a 1.375 GHz radiometry system connected to an electromagnetically (EM) shielded microstrip log spiral antenna optimized for VUR detection. Phantom EM properties are characterized using a coaxial dielectric probe and network analyzer (NA). Power reflection and receive patterns of the antenna are measured in layered tissue phantom. Receiver spectral measurements are used to assess EM shielding provided by a metal cup surrounding the antenna. Radiometer and fiberoptic temperature data are recorded for varying volumes (10–30 mL) and temperatures (40–46°C) of the urine phantom at 35 mm depth surrounded by 36.5°C muscle phantom. Directional receive pattern with about 5% power spectral density at 35 mm target depth and better than −10dB return loss from tissue load are measured for the antenna. Antenna measurements demonstrate no deterioration in power reception and effective EM shielding in the presence of the metal cup. Radiometry power measurements are in excellent agreement with the temperature of the kidney phantom. Laboratory testing of the radiometry system in temperature controlled phantoms supports the feasibility of passive kidney thermometry for VUR detection. PMID:21257366

  17. Titan's surface from the Cassini RADAR radiometry data during SAR mode

    USGS Publications Warehouse

    Paganelli, F.; Janssen, M.A.; Lopes, R.M.; Stofan, E.; Wall, S.D.; Lorenz, R.D.; Lunine, J.I.; Kirk, R.L.; Roth, L.; Elachi, C.

    2008-01-01

    We present initial results on the calibration and interpretation of the high-resolution radiometry data acquired during the Synthetic Aperture Radar (SAR) mode (SAR-radiometry) of the Cassini Radar Mapper during its first five flybys of Saturn's moon Titan. We construct maps of the brightness temperature at the 2-cm wavelength coincident with SAR swath imaging. A preliminary radiometry calibration shows that brightness temperature in these maps varies from 64 to 89 K. Surface features and physical properties derived from the SAR-radiometry maps and SAR imaging are strongly correlated; in general, we find that surface features with high radar reflectivity are associated with radiometrically cold regions, while surface features with low radar reflectivity correlate with radiometrically warm regions. We examined scatterplots of the normalized radar cross-section ??0 versus brightness temperature, outlining signatures that characterize various terrains and surface features. The results indicate that volume scattering is important in many areas of Titan's surface, particularly Xanadu, while other areas exhibit complex brightness temperature variations consistent with variable slopes or surface material and compositional properties. ?? 2007.

  18. Detection of vesicoureteral reflux using microwave radiometry-system characterization with tissue phantoms.

    PubMed

    Arunachalam, Kavitha; Maccarini, Paolo; De Luca, Valeria; Tognolatti, Piero; Bardati, Fernando; Snow, Brent; Stauffer, Paul

    2011-06-01

    Microwave (MW) radiometry is proposed for passive monitoring of kidney temperature to detect vesicoureteral reflux (VUR) of urine that is externally heated by a MW hyperthermia device and thereafter reflows from the bladder to kidneys during reflux. Here, we characterize in tissue-mimicking phantoms the performance of a 1.375 GHz radiometry system connected to an electromagnetically (EM) shielded microstrip log spiral antenna optimized for VUR detection. Phantom EM properties are characterized using a coaxial dielectric probe and network analyzer (NA). Power reflection and receive patterns of the antenna are measured in layered tissue phantom. Receiver spectral measurements are used to assess EM shielding provided by a metal cup surrounding the antenna. Radiometer and fiberoptic temperature data are recorded for varying volumes (10-30 mL) and temperaturesg (40-46°C) of the urine phantom at 35 mm depth surrounded by 36.5°C muscle phantom. Directional receive pattern with about 5% power spectral density at 35 mm target depth and better than -10 dB return loss from tissue load are measured for the antenna. Antenna measurements demonstrate no deterioration in power reception and effective EM shielding in the presence of the metal cup. Radiometry power measurements are in excellent agreement with the temperature of the kidney phantom. Laboratory testing of the radiometry system in temperature-controlled phantoms supports the feasibility of passive kidney thermometry for VUR detection.

  19. Modeling the Detectability of Vesicoureteral Reflux using Microwave Radiometry

    PubMed Central

    Arunachalam, Kavitha; Maccarini, Paolo F.; De Luca, Valeria; Bardati, Fernando; Snow, Brent W.; Stauffer, Paul R

    2010-01-01

    We present the modeling efforts on antenna design, frequency selection and receiver sensitivity estimation to detect vesicoureteral reflux (VUR) using microwave (MW) radiometry as the warm urine from the bladder maintained at fever range temperature using a MW hyperthermia device reflows into the kidneys. Radiometer center frequency (fc), frequency band (Δf), and aperture radius (ra) of the physical antenna for kidney temperature monitoring are determined using a simplified universal antenna model with circular aperture. Anatomical information extracted from computed tomography (CT) images of children age 4–6 years is used to construct a layered 3D tissue model. Radiometric antenna efficiency is evaluated in terms of the ratio between the power collected from the target at depth and the total power received by the antenna (η). Power ratio of the theoretical antenna is used to design a microstrip log spiral antenna with directional radiation pattern over fc ± Δf/2. Power received by the log spiral from the deep target is enhanced using a thin low-loss dielectric matching layer. A cylindrical metal cup is proposed to shield the antenna from electromagnetic interference (EMI). Transient thermal simulations are carried out to determine the minimum detectable change in antenna brightness temperature (δTB) for 15–25 mL urine refluxes at 40–42°C located 35 mm from the skin surface. Theoretical antenna simulations indicate maximum η over 1.1–1.6 GHz for ra = 30–40 mm. Simulations of the 35 mm radius tapered log spiral yielded higher power ratio over fc ± Δf/2 for the 35–40 mm deep targets in the presence of an optimal matching layer. Radiometric temperature calculations indicate δTB ≥ 0.1 K for the 15 mL urine at 40°C and 35 mm depth. Higher η and δTB were observed for the antenna and matching layer inside the metal cup. Reflection measurements of the log spiral in saline phantom are in agreement with the simulation data. Numerical study suggests

  20. Gravitational wave radiometry: Mapping a stochastic gravitational wave background

    NASA Astrophysics Data System (ADS)

    Mitra, Sanjit; Dhurandhar, Sanjeev; Souradeep, Tarun; Lazzarini, Albert; Mandic, Vuk; Bose, Sukanta; Ballmer, Stefan

    2008-02-01

    Virgo detectors that will be sensitive to sources within a thousand times larger spatial volume, could provide promising data sets for GW radiometry.

  1. Mapping Greenland's Firn Aquifer using L-band Microwave Radiometry

    NASA Astrophysics Data System (ADS)

    Miller, J.; Bringer, A.; Jezek, K. C.; Johnson, J. T.; Scambos, T. A.; Long, D. G.

    2016-12-01

    Greenland's recently discovered firn aquifer is one of the most interesting, yet still mysterious, components of the ice sheet system. Many open questions remain regarding timescales of refreezing and/or englacial drainage of liquid meltwater, and the connections of firn aquifers to the subglacial hydrological system. If liquid meltwater production at the surface of the Greenland ice sheet continues to increase, subsequent increases in the volume of mobile liquid meltwater retained within Greenland's firn aquifer may increase the possibility of crevasse-deepening via hydrofracture. Hydrofracture is an important component of supraglacial lake drainage leading to at least temporary accelerated flow velocities and ice sheet mass balance changes. Firn aquifers may also support hydrofracture-induced drainage and thus are potentially capable of significantly influencing ice sheet mass balance and sea level rise. Spaceborne L-band microwave radiometers provide an innovative tool for ice-sheet wide mapping of the spatiotemporal variability of Greenland's firn aquifer. Both refreezing and englacial drainage may be observable given the sensitivity of the microwave response to the upper surface of liquid meltwater retained within snow and firn pore space as well as the ability of L band instruments to probe the ice sheet from the surface to the firn-ice transition at pore close-off depth. Here we combine L-band (1.4 GHz) brightness temperature observations from multiple sources to demonstrate the potential of mapping firn aquifers on ice sheets using L-band microwave radiometry. Data sources include the interferometric MIRAS instrument aboard ESA's Soil Moisture and Ocean Salinity (SMOS) satellite mission and the radiometer aboard NASA's Soil Moisture Active Passive (SMAP) satellite mission. We will also present mulit-frequency L-band brightness temperature data (0.5-2 GHz) that will be collected over several firn aquifer areas on the Greenland ice sheet by the Ohio State

  2. Global and Seasonal Distributions of Mesospheric OH Emissions from SABER

    NASA Astrophysics Data System (ADS)

    Baker, D. J.; Fielding, R. L.; Aston, R. C.; Hancock, J. J.; Reese, K. B.; Mlynczak, M. G.; Russell, J. M.

    2004-12-01

    On December 7, 2001, SABER, a cooled multichannel radiometer, was launched aboard the TIMED satellite. In January of 2002 the SABER instrument began returning airglow limb scan measurements from around the globe. Data now available include 65% of 2002, 75% of 2003, and 40% of 2004. Experimental data were taken from SABER for two radiometric channels centered at λ =1.6 μ m and 2.06 μ m. Volume emission rates (VER) were computed at the peaks of the OH layer profiles and then the magnitudes were displayed as a function of the latitude and longitude of the tangent point of the observation. The Mlynczak unfiltering algorithm for OH emissions was used to obtain absolute values for the maximum VER of the total sequence of OH vibration-rotation band emissions. The maximum VER was found to be greater near the equator compared with high latitudes. In addition, seasonal effects on the global distribution of the nighttime OH airglow were explored for the available data in 2002, 2003, and part of 2004. Algorithmic methods of optimized geographic visualization for this unprecedented wealth of mesospheric airglow data were also explored.

  3. Remote Sensing of Tropical Cyclones: Applications from Microwave Radiometry and Global Navigation Satellite System Reflectometry

    NASA Astrophysics Data System (ADS)

    Morris, Mary

    Tropical cyclones (TCs) are important to observe, especially over the course of their lifetimes, most of which is spent over the ocean. Very few in situ observations are available. Remote sensing has afforded researchers and forecasters the ability to observe and understand TCs better. Every remote sensing platform used to observe TCs has benefits and disadvantages. Some remote sensing instruments are more sensitive to clouds, precipitation, and other atmospheric constituents. Some remote sensing instruments are insensitive to the atmosphere, which allows for unobstructed observations of the ocean surface. Observations of the ocean surface, either of surface roughness or emission can be used to estimate ocean surface wind speed. Estimates of surface wind speed can help determine the intensity, structure, and destructive potential of TCs. While there are many methods by which TCs are observed, this thesis focuses on two main types of remote sensing techniques: passive microwave radiometry and Global Navigation Satellite System reflectometry (GNSS-R). First, we develop and apply a rain rate and ocean surface wind speed retrieval algorithm for the Hurricane Imaging Radiometer (HIRAD). HIRAD, an airborne passive microwave radiometer, operates at C-band frequencies, and is sensitive to rain absorption and emission, as well as ocean surface emission. Motivated by the unique observing geometry and high gradient rain scenes that HIRAD typically observes, a more robust rain rate and wind speed retrieval algorithm is developed. HIRAD's observing geometry must be accounted for in the forward model and retrieval algorithm, if high rain gradients are to be estimated from HIRAD's observations, with the ultimate goal of improving surface wind speed estimation. Lastly, TC science data products are developed for the Cyclone Global Navigation Satellite System (CYGNSS). The CYGNSS constellation employs GNSS-R techniques to estimate ocean surface wind speed in all precipitating

  4. All-sky, narrowband, gravitational-wave radiometry with folded data

    NASA Astrophysics Data System (ADS)

    Thrane, Eric; Mitra, Sanjit; Christensen, Nelson; Mandic, Vuk; Ain, Anirban

    2015-06-01

    Gravitational-wave radiometry is a powerful tool by which weak signals with unknown signal morphologies are recovered through a process of cross correlation. Radiometry has been used, e.g., to search for persistent signals from known neutron stars such as Scorpius X-1. In this paper, we demonstrate how a more ambitious search—for persistent signals from unknown neutron stars—can be efficiently carried out using folded data, in which an entire ˜year-long observing run is represented as a single sidereal day. The all-sky, narrowband radiometer search described here will provide a computationally tractable means to uncover gravitational-wave signals from unknown, nearby neutron stars in binary systems, which can have modulation depths of ≈0.1 - 2 Hz . It will simultaneously provide a sensitive search algorithm for other persistent, narrowband signals from unexpected sources.

  5. Microwave radiometry for continuous non-contact temperature measurements during microwave heating.

    PubMed

    Stephan, Karl D; Pearce, John A

    2005-01-01

    Temperature measurement during microwave heating in industrial and commercial processes can improve quality, throughput, and energy conservation. Conventional ways of measuring temperature inside a microwave oven cavity are costly, inconvenient, or unsuitable for high-volume industrial applications. In this paper, we describe the theory of microwave radiometry as applied to the measurement of temperature during microwave heating. By extending the theory of radiative transfer to the case of thermal microwave radiation inside a cavity, we show that the same characteristics which make a microwave cavity suitable for heating materials also assist in obtaining meaningful temperature data with microwave radiometry. We present experimental data from the heating of liquid and solid materials which confirm the essential features of the theory, and show agreement between this method and more conventional methods of +/-4 degrees C.

  6. EBE/ECE Radiometry on COMPASS Tokamak - Design and First Measurements

    SciTech Connect

    Zajac, J.; Preinhaelter, J.; Urban, J.; Sestak, D.; Nanobashvili, S.

    2009-11-26

    COMPASS tokamak has started its operation in IPP Prague recently. A new 16-channel radiometry system has been designed and manufactured for the electron Bernstein/cyclotron wave emission (EBE/ECE) experiments. For EBE studies, based on EBW-X-O mode conversion, radiometry in Ka-band (26.5-40 GHz will be used which corresponds to the fundamental EC harmonics for the low-B{sub t}(B{sub o}{approx}1.2 T) tokamak operation. Alternatively, an E-band antenna and front-end (60-73.5/76.5-90 GHz) will be used with the same 16-channel receiver for the conventional second harmonics ECE diagnostics. In the contribution the design of the system is described as well as the initial testing measurements on tokamak COMPASS.

  7. Wavelength-modulated differential photothermal radiometry: Theory and experimental applications to glucose detection in water

    NASA Astrophysics Data System (ADS)

    Mandelis, Andreas; Guo, Xinxin

    2011-10-01

    A differential photothermal radiometry method, wavelength-modulated differential photothermal radiometry (WM-DPTR), has been developed theoretically and experimentally for noninvasive, noncontact biological analyte detection, such as blood glucose monitoring. WM-DPTR features analyte specificity and sensitivity by combining laser excitation by two out-of-phase modulated beams at wavelengths near the peak and the base line of a prominent and isolated mid-IR analyte absorption band (here the carbon-oxygen-carbon bond in the pyran ring of the glucose molecule). A theoretical photothermal model of WM-DPTR signal generation and detection has been developed. Simulation results on water-glucose phantoms with the human blood range (0-300 mg/dl) glucose concentration demonstrated high sensitivity and resolution to meet wide clinical detection requirements. The model has also been validated by experimental data of the glucose-water system obtained using WM-DPTR.

  8. Fundamental principles of absolute radiometry and the philosophy of this NBS program (1968 to 1971)

    NASA Technical Reports Server (NTRS)

    Geist, J.

    1972-01-01

    A description is given work performed on a program to develop an electrically calibrated detector (also called absolute radiometer, absolute detector, and electrically calibrated radiometer) that could be used to realize, maintain, and transfer a scale of total irradiance. The program includes a comprehensive investigation of the theoretical basis of absolute detector radiometry, as well as the design and construction of a number of detectors. A theoretical analysis of the sources of error is also included.

  9. Remote sensing of the atmosphere of Mars using infrared pressure modulation and filter radiometry

    NASA Technical Reports Server (NTRS)

    Mccleese, D. J.; Schofield, J. T.; Zurek, R. W.; Martonchik, J. V.; Haskins, R. D.

    1986-01-01

    The study of the atmosphere and climate of Mars will soon be advanced considerably by the Mars Observer mission. This paper describes the atmospheric sounder for this mission and how it will measure key Martian atmospheric parameters using IR gas correlation and filter radiometry. The instrument now under development will provide high-resolution vertical profiles of atmospheric temperature, pressure, water vapor, dust, and clouds using limb sounding techniques as well as nadir observations of surface thermal properties and polar radiative balance.

  10. Approach of the measurement of thermal diffusivity of mural paintings by front face photothermal radiometry

    NASA Astrophysics Data System (ADS)

    Candoré, Jean Charles; Bodnar, J. L.; Detalle, Vincent; Remy, B.; Grossel, Philippe

    2010-03-01

    In this paper we present, in an experimental way, the possibilities of front face photothermal radiometry to measure, in situ, the longitudinal thermal diffusivity of mural paintings. First, we present the principle of the method of measurement. Then, we present the experimental device implemented for the study. Finally, we show, using the experimental study of a plaster sample, the photothermal method allows in a particular case, a good approximation of the parameter longitudinal thermal diffusivity.

  11. Dielectric Wakefield Accelerator Experiments at the SABER Facility

    SciTech Connect

    Kanareykin, A.; Thompson, M.C.; Berry, M.K.; Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; Badakov, H.; Cook, A.M.; Rosenzweig, J.B.; Tikhoplav, R.; Travish, G.; Muggli, P.; /Southern California U.

    2008-01-28

    Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC Final Focus Test Beam (FFTB), are foreseen to be produced at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of multi-GV/m in plasmas. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 um and 200 um ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in fused silica (with full data analysis still ongoing) [1]. With the construction and commissioning of the SABER facility at SLAC, new experiments would be made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and proof of acceleration in tubes >10 cm in length. This collaboration will investigate breakdown thresholds and accelerating fields in new materials including CVD diamond. Here we describe the experimental plans, beam parameters, simulations, and progress to date as well as future prospects for machines based of DWA structures.

  12. Occurrence of steam pops during irrigated RF ablation: novel insights from microwave radiometry.

    PubMed

    Koruth, Jacob S; Dukkipati, Srinivas; Gangireddy, Sandeep; McCarthy, John; Spencer, Darren; Weinberg, Alan D; Miller, Marc A; D'Avila, Andre; Reddy, Vivek Y

    2013-11-01

    The disparity between catheter and tissue temperatures during irrigated RF ablation frustrates one's ability to predict steam pops. Microwave radiometry allows for "volumetric" temperature assessment-i.e., within a circumscribed volume around the catheter tip-permitting, direct assessment of temperature during ablation. The aim of this study was to examine (i) the ability of microwave radiometry to predict steam pops, and (ii) compare this to traditional parameters such as power, catheter temperature, and impedance. Irrigated RF ablation was performed in 8 sheep using the Tempasure ablation catheter in all chambers. Power, impedance, catheter tip, and volumetric temperature were continually monitored. Ablation was terminated after a pop or at 60 seconds. A pop was defined as an audible or visualized pop (intracardiac echocardiography). Predictors of pops were determined by univariate and multivariate GEE logistic regression modeling. A total of 48 pops occurred during 143 lesions applied at 20-50 W. There was no association between the chamber of the heart and the occurrence of pops. The rate of rise of volumetric temperature (greater than 1.5 °C/s) was the single best predictor of pops (OR: 88.8 [95% CI: 12-604], P < 0.0007). Pops only occurred above a maximum volumetric temperature threshold of 89 °C. During irrigated RF ablation, steam pop occurrence can be predicted by both, the rate of rise and the maximum volumetric temperature measured by microwave radiometry. © 2013 Wiley Periodicals, Inc.

  13. Titan's surface from Cassini RADAR SAR and high resolution radiometry data of the first five flybys

    USGS Publications Warehouse

    Paganelli, F.; Janssen, M.A.; Stiles, B.; West, R.; Lorenz, R.D.; Lunine, J.I.; Wall, S.D.; Callahan, P.; Lopes, R.M.; Stofan, E.; Kirk, R.L.; Johnson, W.T.K.; Roth, L.; Elachi, C.; ,

    2007-01-01

    The first five Titan flybys with Cassini's Synthetic Aperture RADAR (SAR) and radiometer are examined with emphasis on the calibration and interpretation of the high-resolution radiometry data acquired during the SAR mode (SAR-radiometry). Maps of the 2-cm wavelength brightness temperature are obtained coincident with the SAR swath imaging, with spatial resolution approaching 6 km. A preliminary calibration shows that brightness temperature in these maps varies from 64 to 89 K. Surface features and physical properties derived from the SAR-radiometry maps and SAR imaging are strongly correlated; in general, we find that surface features with high radar reflectivity are associated with radiometrically cold regions, while surface features with low radar reflectivity correlate with radiometrically warm regions. We examined scatterplots of the normalized radar cross-section ??0 versus brightness temperature, finding differing signatures that characterize various terrains and surface features. Implications for the physical and compositional properties of these features are discussed. The results indicate that volume scattering is important in many areas of Titan's surface, particularly Xanadu, while other areas exhibit complex brightness temperature variations consistent with variable slopes or surface material and compositional properties. ?? 2007 Elsevier Inc.

  14. Experimental evaluation of theoretical sea surface reflectance factors relevant to above-water radiometry.

    PubMed

    Zibordi, Giuseppe

    2016-03-21

    Determination of the water-leaving radiance LW through above-water radiometry requires knowledge of accurate reflectance factors ρ of the sea surface. Publicly available ρ relevant to above-water radiometry include theoretical data sets generated: i. by assuming a sky radiance distribution accounting for aerosols and multiple scattering, but neglecting polarization, and quantifying sea surface effects through Cox-Munk wave slope statistics; or differently ii. accounting for polarization, but assuming an ideal Rayleigh sky radiance distribution, and quantifying sea surface effects through modeled wave elevation and slope variance spectra. The impact on above-water data products of differences between those factors ρ was quantified through comparison of LW from the Ocean Color component of the Aerosol Robotic Network (AERONET-OC) with collocated LW from in-water radiometry. Results from the analysis of radiance measurements from the sea performed with 40 degrees viewing angle and 90 degrees azimuth offset with respect to the sun plane, indicated a slightly better agreement between above- and in-water LW determined for wind speeds tentatively lower than 4 m s-1 with ρ computed accounting for aerosols, multiple scattering and Cox-Munk surfaces. Nevertheless, analyses performed by partitioning the investigated data set also indicated that actual ρ values would exhibit dependence on sun zenith comprised between those characterizing the two sets of reflectance factors.

  15. Titan's Surface from Cassini RADAR SAR and High Resolution Radiometry Data of the First Five Flybys

    NASA Technical Reports Server (NTRS)

    Paganelli, F.; Janssen, M. A.; Stiles, B.; West, R.; Lorenz, R. D.; Lunine, J. I.; Wall, S. D.; Callahan, P.; Lopes, R. M.; Stofan, E.; Kirk, R. L.; Johnson, W. T. K.; Roth, L.; Elachi, C.

    2007-01-01

    The first five Titan flybys with Cassini's Synthetic Aperture RADAR (SAR) and radiometer are examined with emphasis on the calibration and interpretation of the high-resolution radiometry data acquired during the SAR mode (SAR-radiometry). Maps of the 2-cm wavelength brightness temperature are obtained coincident with the SAR swath imaging, with spatial resolution approaching 6 km. A preliminary calibration shows that brightness temperature in these maps varies from 64 to 89 K. Surface features and physical properties derived from the SAR-radiometry maps and SAR imaging are strongly correlated; in general, we find that surface features with high radar reflectivity are associated with radiometrically cold regions, while surface features with low radar reflectivity correlate with radiometrically warm regions. We examined scatterplots of the normalized radar cross-section sigma(exp o) versus brightness temperature, finding differing signatures that characterize various terrains and surface features. Implications for the physical and compositional properties of these features are discussed. The results indicate that volume scattering is important in many areas of Titan's surface, particularly Xanadu, while other areas exhibit complex brightness temperature variations consistent with variable slopes or surface material and compositional properties.

  16. Familia and Comunidad-Based Saberes: Learning in an Indigenous Heritage Community

    ERIC Educational Resources Information Center

    Urrieta, Luis, Jr.

    2013-01-01

    This article explores how children and youth learned indigenous heritage "saberes" (knowings) through intent community participation in Nocutzepo, Mexico. The "familia" (family) and "comunidad" (community)-based saberes were valuable for skills acquisition, but most important for learning indigenous forms of…

  17. Familia and Comunidad-Based Saberes: Learning in an Indigenous Heritage Community

    ERIC Educational Resources Information Center

    Urrieta, Luis, Jr.

    2013-01-01

    This article explores how children and youth learned indigenous heritage "saberes" (knowings) through intent community participation in Nocutzepo, Mexico. The "familia" (family) and "comunidad" (community)-based saberes were valuable for skills acquisition, but most important for learning indigenous forms of…

  18. High-temperature measurement techniques for the application in photometry, radiometry and thermometry

    NASA Astrophysics Data System (ADS)

    Hartmann, Jürgen

    2009-01-01

    Well characterised sources of thermal radiation are essential for photometry, radiometry, and thermometry. They serve as reference radiators for the calibration of detectors and radiance sources. Thermal radiation sources are advantageous for this purpose compared to other radiance sources such as lamps or LEDs because they possess a continuous spectrum of the emitted spectral radiance, which, for blackbody sources, can be calculated analytically using Planck’s law of radiation. For application in thermometry, blackbody sources starting from temperatures near absolute zero to temperatures up to 3000 ∘C are needed for the calibration of radiation thermometers. For application in photometry and radiometry high intensity sources of radiation in the visible and UV region of the optical spectrum were required. This latter requirement is met by blackbody sources at temperatures well above 2000 ∘C. An ideal reference source should always emit the same amount of radiation at any time of use. This is realised by fixed-point radiators. Such radiators are based on a phase transition of a substance, at high temperatures the melting and freezing points of metals. However, current metal fixed-points are limited to relatively low temperatures. In the present work innovative techniques necessary for research into high-temperature thermal radiation sources are developed and thoroughly described. Starting with variable temperature blackbody sources the techniques required are: Precise apertures determination and detailed characterisation of the applied optical detectors. The described techniques are then used to undertake research into the development of high-temperature fixed-points above the copper fixed-point for application in photometry, radiometry, and thermometry. Applying these sophisticated techniques it was shown that these new high-temperature fixed-points are reproducible and repeatable to better than 100 mK at temperatures up to nearly 3200 K. Finally, a forward

  19. Assessing the effect of vegetation in the estimation of soil properties with field VNIR radiometry

    NASA Astrophysics Data System (ADS)

    Melendez-Pastor, I.; Córdoba-Sola, P.; Navarro-Pedreño, J.; Gómez, I.; Koch, M.

    2009-04-01

    Spectroradiometric soil surveys (field radiometry) are a valuable technique for soil classification and properties estimation. Field radiometry combines -in a relatively easy-to-use procedure- a fast, accurate and non-destructive sampling method. A wide range of soil properties have been quantitatively estimated with field or laboratory radiometry. In addition, field radiometry is a basic stage in remote sensing studies. It allows the up-scaling process of soil, vegetation or water parameters from the ground level to the airborne or spaceborne sensors level. Field radiometry plays a crucial role in training and validation stages of quantitative remote sensing. A complex problem in remote sensing appears when several components are mixed within a pixel and the resulting pixel's spectrum is a combination of the individual components. This work assess the effect of vegetation in soil properties estimation with linear regression models. Field spectra were taken from soil-vegetation mixtures under natural illumination with a portable spectroradiometer in the visible and near-infrared (VNIR) spectral range. Soil and vegetation samples for each radiometric sampling point were taken and analyzed in laboratory. Soil moisture content and soil organic carbon measured by the LOI (Loss-On-Ignition) method (Konen et al. 2002) were used in this approach. A derivative analysis of field spectra was used to determine the position and magnitude of absorption bands according to the method employed by Melendez-Pastor et al. (2008). Pearson correlations between soil parameters and each spectral band were computed and correlograms for the first and second derivate were obtained. Maximum (approximates to +1) and minimum (approximates to -1) Pearson correlations were used to normalize correlograms between 0 to 1. High relatively correlated bands (with values ranging from 0 to 0.1 or from 0-9 to 1 for the normalized correlograms) were identified and used as explicative variables in the

  20. Characterization of a Digital Microwave Radiometry System for Noninvasive Thermometry using Temperature Controlled Homogeneous Test Load

    PubMed Central

    Arunachalam, K; Stauffer, P R; Maccarini, PF; Jacobsen, S; Sterzer, F

    2009-01-01

    Microwave radiometry has been proposed as a viable noninvasive thermometry approach for monitoring subsurface tissue temperatures and potentially controlling power levels of multielement heat applicators during clinical hyperthermia treatments. With the evolution of technology, several analog microwave radiometry devices have been developed for biomedical applications. In this paper, we describe a digital microwave radiometer with built-in electronics for signal processing and automatic self-calibration. Performance of the radiometer with an Archimedean spiral receive antenna is evaluated over a bandwidth of 3.7–4.2GHz in homogeneous and layered water test loads. Controlled laboratory experiments over the range of 30–50°C characterize measurement accuracy, stability, repeatability and penetration depth sensitivity. The ability to sense load temperature through an intervening water coupling bolus of 6mm thickness is also investigated. To assess clinical utility and sensitivity to electromagnetic interference (EMI), experiments are conducted inside standard clinical hyperthermia treatment rooms with no EM shielding. The digital radiometer provided repeatable measurements with 0.075°C resolution and standard deviation of 0.217°C for homogeneous and layered tissue loads at temperatures between 32–45°C. Within the 3.7–4.2GHz band, EM noise rejection was good other than some interference from overhead fluorescent lights in the same room as the radiometer. The system response obtained for ideal water loads suggests that this digital radiometer should be useful for estimating subcutaneous tissue temperatures under a 6mm waterbolus used during clinical hyperthermia treatments. The accuracy and stability data obtained in water test loads of several configurations support our expectation that single band radiometry should be sufficient for sub-surface temperature monitoring and power control of large multielement array superficial hyperthermia applicators. PMID

  1. Effects of two large solar energetic particle events on middle atmosphere nighttime odd hydrogen and ozone content: Aura/MLS and TIMED/SABER measurements

    NASA Astrophysics Data System (ADS)

    Verkhoglyadova, O. P.; Wang, S.; Mlynczak, M. G.; Hunt, L. A.; Zank, G. P.

    2015-01-01

    is well established that large solar energetic particle (SEP) events affect ozone in the middle atmosphere through chemical reactions involving odd hydrogen (HOx) species. We analyze global middle atmospheric effects at local nighttime for two large SEP events during the intervals of 7-17 November 2004 and 20-30 August 2005. Properties of the SEP events and concomitant geomagnetic storms are discussed using in situ measurements. Temporal dynamics and latitudinal distribution of HOx and ozone densities inferred from measurements by the Aura/MLS (Microwave Limb Sounder) instrument are analyzed. We show statistically significant increases of nighttime hydroxyl (OH) density in the middle atmosphere up to 5°106 cm-3 in the latitude range from 70° down to 50° latitude in northern and to -40° latitude in southern hemispheres in connection with peaks in proton fluxes of >10 MeV energy range measured by GOES spacecraft. During the storm main phases, the nighttime OH density increases were observed around ±50° in southern and northern hemispheres in the altitude range of 65-80 km. There is a correspondence between averaged nighttime OH partial column density (in 0.005 to 0.1 hPa pressure range) in the polar latitudes and energetic proton (>10 MeV) fluxes. Corresponding statistically significant nighttime ozone destructions up to 45% are observed from 70° down to 60° latitude in the northern and southern hemispheres. The SEP impulsive phases correspond to onsets of ozone density depletions. Larger relative ozone destructions are observed in the northern hemisphere in November and in the southern hemisphere in August. Simultaneous measurements of ozone density by the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry (TIMED/SABER) instrument independently confirm the MLS results.

  2. Satellite microwave radiometry of sea ice of polar regions: a review

    NASA Astrophysics Data System (ADS)

    Tikhonov, V. V.; Raev, M. D.; Sharkov, E. A.; Boyarskii, D. A.; Repina, I. A.; Komarova, N. Yu.

    2016-12-01

    This is a review of methods of passive microwave satellite monitoring of the sea-ice cover in polar regions. We briefly describe the microwave radiometers launched into the Earth's orbit and provide data used in studies of Arctic and Antarctic sea ice. We give a detailed description of currently used algorithms for determining the sea-ice concentration and cover in polar regions according to satellite microwave radiometry. The methods for constructing these algorithms and their related drawbacks are considered. The final section of this paper briefly analyzes the studies that compare current algorithms with each other, with radar data, infrared data, and data of visual ship observations.

  3. Comparison of photoacoustic radiometry to gas chromatography/mass spectrometry methods for monitoring chlorinated hydrocarbons

    SciTech Connect

    Sollid, J.E.; Trujillo, V.L.; Limback, S.P.; Woloshun, K.A.

    1996-03-01

    A comparison of two methods of gas chromatography mass spectrometry (GCMS) and a nondispersive infrared technique, photoacoustic radiometry (PAR), is presented in the context of field monitoring a disposal site. First is presented an historical account describing the site and early monitoring to provide an overview. The intent and nature of the monitoring program changed when it was proposed to expand the Radiological Waste Site close to the Hazardous Waste Site. Both the sampling methods and analysis techniques were refined in the course of this exercise.

  4. SABERS. Stand-Alone ADIC Binary Exploitation Resources System. Volume II.

    DTIC Science & Technology

    1981-09-01

    revere, side it neconnwo’ mid Identify by block number) Data Base Management Systems ADCOM Applications Transaction Processing Orbital Mechanics G aphic...Systems * and improved analyst capability for the ADCOM Intelligence Center (ADIC) and its missions. In addition, SABERS has developed system software...structure. SABERS was developed to provide a set of tools for demonstrating improvements to space and missile analysts at the ADCOM Intelligence Center

  5. Evaluation of AERONET precipitable water vapor versus microwave radiometry, GPS, and radiosondes at ARM sites

    NASA Astrophysics Data System (ADS)

    Pérez-Ramírez, Daniel; Whiteman, David N.; Smirnov, Alexander; Lyamani, Hassan; Holben, Brent N.; Pinker, Rachel; Andrade, Marcos; Alados-Arboledas, Lucas

    2014-08-01

    In this paper we present comparisons of Aerosol Robotic Network (AERONET) precipitable water vapor (W) retrievals from Sun photometers versus radiosonde observations and other ground-based retrieval techniques such as microwave radiometry (MWR) and GPS. The comparisons make use of the extensive measurements made within the U.S. Department of Energy Atmospheric Radiation Measurement Program (ARM), mainly at their permanent sites located at the Southern Great Plains (Oklahoma, U.S.), Nauru Islands, and Barrow (Alaska, U.S.). These places experience different types of weather which allows the comparison of W under different conditions. Radiosonde and microwave radiometry data were provided by the ARM program while the GPS data were obtained from the SOUMINET network. In general, W obtained by AERONET is lower than those obtained by MWR and GPS by ~6.0-9.0% and ~6.0-8.0%, respectively. The AERONET values are also lower by approximately 5% than those obtained from the numerous balloon-borne radiosondes launched at the Southern Great Plains. These results point toward a consistent dry bias in the retrievals of W by AERONET of approximately 5-6% and a total estimated uncertainty of 12-15%. Differences with respect to MWR retrievals are a function of solar zenith angle pointing toward a possible bias in the MWR retrievals. Finally, the ability of AERONET precipitable water vapor retrievals to provide long-term records of W in diverse climate regimes is demonstrated.

  6. A laboratory module on radiometry, photometry and colorimetry for an undergraduate optics course

    NASA Astrophysics Data System (ADS)

    Polak, Robert D.

    2014-07-01

    The bachelor's degree in Physics at Loyola University Chicago requires both an upper-division course in Optics as well as a companion Optics Laboratory course. Recently, the laboratory course has undergone dramatic changes. Traditional weekly laboratories have been replaced with three laboratory modules, where students focus on a single topic over several weeks after which the students submit a laboratory report written in the style of a journal article following American Institute of Physics style manual. With this method, students are able to gain a deeper understanding of the specific topic areas of radiometry, photometry and colorimetry, lens design and aberrations, and polarization and interference while using industry-standard equipment and simulation software. In particular, this work will provide the details of the laboratory module on radiometry, photometry and colorimetry where students use a photoradiometer and integrating sphere to characterize the optical properties of an LCD monitor, light bulb and a fiber optic light source calculating properties such as luminous flux, luminous intensity, luminance, CIE color coordinates, NTSC ratio, color temperature and luminous efficacy.

  7. Validation of microwave radiometry for measuring the internal temperature profile of human tissue

    NASA Astrophysics Data System (ADS)

    Levick, A.; Land, D.; Hand, J.

    2011-06-01

    A phantom target with a known linear temperature gradient has been developed for validating microwave radiometry for measuring internal temperature profiles within human tissue. The purpose of the phantom target is to simulate the temperature gradient found within the surface layers of a baby's brain during hypothermal neuroprotection therapy, in which the outer surface of the phantom represents the skin surface and the inner surface the brain core. The target comprises a volume of phantom tissue material with similar dielectric properties to high water-content human tissue, contained between two copper plates at known temperatures. The antenna of a microwave radiometer is in contact with one surface of the phantom material. We have measured the microwave temperature of the phantom with microwave radiometry in a frequency band of 3.0-3.5 GHz. Our microwave temperature measurements have small 0.05 °C (type A) uncertainties associated with random effects and provide temperatures consistent with values determined using theoretical models of the antenna-target system within uncertainties. The measurements are in good agreement with the major signal contribution being formed over a near plane-wave response within the material with a much smaller contribution from close to the antenna face.

  8. Heating of industrial sewing machine needles: FEA model and verification using IR radiometry

    NASA Astrophysics Data System (ADS)

    Li, Qinwen; Liasi, Evangelos; Simon, Daniel L.; Du, Ruxu; Bujas-Dimitrijevic, Jasmina; Chen, Anshi

    1999-03-01

    With the use of synthetic fabrics and threads in high speed sewing, needle heating due to friction between the needle and the fabric becomes a serious problem which limits further increase of the sewing speed. The high temperature in the needle can accelerate thread wear, cause wear at the needle eye, and damage the thread. It can also scorch the fabric, as well as temper and weaken the needle itself. Experimental methods, such as: infrared radiometry, infrared pyrometry, etc., have been applied to analyze this problem in previous studies. They revealed some important factors that affect the needle peak steady state temperature. In this study the numerical (FEA) model developed to simulate the needle heating is fine tuned and verified via infrared radiometry. The FEA model incorporates detailed needle geometry and the effects of thread on needle heating. It deals with a transient heat transfer process with time and position dependent boundary conditions. It correlates various important factors that affect the needle heating, such as needle characteristics, fabric properties, and sewing conditions to the needle temperature distribution. Given various needle geometries, sewing conditions, and fabric properties, the model can simulate the needle heating process, including the initial heating phase and the steady state. It can also predict the temperature distribution in the needle as well as the time to reach steady state. The trends of the simulation results correlate well with experiments.

  9. High-efficiency non-uniformity correction for wide dynamic linear infrared radiometry system

    NASA Astrophysics Data System (ADS)

    Li, Zhou; Yu, Yi; Tian, Qi-Jie; Chang, Song-Tao; He, Feng-Yun; Yin, Yan-He; Qiao, Yan-Feng

    2017-09-01

    Several different integration times are always set for a wide dynamic linear and continuous variable integration time infrared radiometry system, therefore, traditional calibration-based non-uniformity correction (NUC) are usually conducted one by one, and furthermore, several calibration sources required, consequently makes calibration and process of NUC time-consuming. In this paper, the difference of NUC coefficients between different integration times have been discussed, and then a novel NUC method called high-efficiency NUC, which combines the traditional calibration-based non-uniformity correction, has been proposed. It obtains the correction coefficients of all integration times in whole linear dynamic rangesonly by recording three different images of a standard blackbody. Firstly, mathematical procedure of the proposed non-uniformity correction method is validated and then its performance is demonstrated by a 400 mm diameter ground-based infrared radiometry system. Experimental results show that the mean value of Normalized Root Mean Square (NRMS) is reduced from 3.78% to 0.24% by the proposed method. In addition, the results at 4 ms and 70 °C prove that this method has a higher accuracy compared with traditional calibration-based NUC. In the meantime, at other integration time and temperature there is still a good correction effect. Moreover, it greatly reduces the number of correction time and temperature sampling point, and is characterized by good real-time performance and suitable for field measurement.

  10. Infrared radiometry of dental enamel during Er:YAG and Er:YSGG laser irradiation

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Visuri, Steven R.; Featherstone, John D.; Walsh, Joseph T.; Seka, Wolf D.; Glena, Richard E.; McCormack, Sandra M.; Wigdor, Harvey A.

    1996-10-01

    Time-resolved infrared radiometry was used to measure surface temperatures during pulsed Er:YSGG and Er:YAG laser irradiation of dental enamel. Scanning electron microscopy (SEM) was used to determine the melting and vaporization thresholds and to characterize other changes in the surface morphology. The magnitude and temporal evolution of the surface temperature during multiple-pulse irradiation of the tissue was dependant on the wavelength, fluence, and pre- exposure to laser pulses. Radiometry and SEM micrographs indicate that ablation is initiated at temperatures well below the melting and vaporization temperatures of the carbonated hydroxyapatite mineral component. Ablation occurred at lower surface temperatures and at a lower fluences for Er:YAG than for Er:YSGG laser irradiation: 400 degrees C versus 800 degrees C and above 7 J/cm2 versus 18/Jcm2, respectively. However, the measured surface temperatures were higher at (lambda) equals 2.79 (Mu) m than at (lambda) equals 2.94 during low fluence irradiation. Spatially dependent absorption in the enamel matrix is proposed to explain this apparent contradiction.

  11. Monitoring local heating around an interventional MRI antenna with RF radiometry

    PubMed Central

    Ertürk, M. Arcan; El-Sharkawy, AbdEl-Monem M.; Bottomley, Paul A.

    2015-01-01

    Purpose: Radiofrequency (RF) radiometry uses thermal noise detected by an antenna to measure the temperature of objects independent of medical imaging technologies such as magnetic resonance imaging (MRI). Here, an active interventional MRI antenna can be deployed as a RF radiometer to measure local heating, as a possible new method of monitoring device safety and thermal therapy. Methods: A 128 MHz radiometer receiver was fabricated to measure the RF noise voltage from an interventional 3 T MRI loopless antenna and calibrated for temperature in a uniformly heated bioanalogous gel phantom. Local heating (ΔT) was induced using the antenna for RF transmission and measured by RF radiometry, fiber-optic thermal sensors, and MRI thermometry. The spatial thermal sensitivity of the antenna radiometer was numerically computed using a method-of-moment electric field analyses. The gel’s thermal conductivity was measured by MRI thermometry, and the localized time-dependent ΔT distribution computed from the bioheat transfer equation and compared with radiometry measurements. A “H-factor” relating the 1 g-averaged ΔT to the radiometric temperature was introduced to estimate peak temperature rise in the antenna’s sensitive region. Results: The loopless antenna radiometer linearly tracked temperature inside a thermally equilibrated phantom up to 73 °C to within ±0.3 °C at a 2 Hz sample rate. Computed and MRI thermometric measures of peak ΔT agreed within 13%. The peak 1 g-average temperature was H = 1.36 ± 0.02 times higher than the radiometric temperature for any media with a thermal conductivity of 0.15–0.50 (W/m)/K, indicating that the radiometer can measure peak 1 g-averaged ΔT in physiologically relevant tissue within ±0.4 °C. Conclusions: Active internal MRI detectors can serve as RF radiometers at the MRI frequency to provide accurate independent measures of local and peak temperature without the artifacts that can accompany MRI thermometry or

  12. Monitoring local heating around an interventional MRI antenna with RF radiometry.

    PubMed

    Ertürk, M Arcan; El-Sharkawy, AbdEl-Monem M; Bottomley, Paul A

    2015-03-01

    Radiofrequency (RF) radiometry uses thermal noise detected by an antenna to measure the temperature of objects independent of medical imaging technologies such as magnetic resonance imaging (MRI). Here, an active interventional MRI antenna can be deployed as a RF radiometer to measure local heating, as a possible new method of monitoring device safety and thermal therapy. A 128 MHz radiometer receiver was fabricated to measure the RF noise voltage from an interventional 3 T MRI loopless antenna and calibrated for temperature in a uniformly heated bioanalogous gel phantom. Local heating (ΔT) was induced using the antenna for RF transmission and measured by RF radiometry, fiber-optic thermal sensors, and MRI thermometry. The spatial thermal sensitivity of the antenna radiometer was numerically computed using a method-of-moment electric field analyses. The gel's thermal conductivity was measured by MRI thermometry, and the localized time-dependent ΔT distribution computed from the bioheat transfer equation and compared with radiometry measurements. A "H-factor" relating the 1 g-averaged ΔT to the radiometric temperature was introduced to estimate peak temperature rise in the antenna's sensitive region. The loopless antenna radiometer linearly tracked temperature inside a thermally equilibrated phantom up to 73 °C to within ±0.3 °C at a 2 Hz sample rate. Computed and MRI thermometric measures of peak ΔT agreed within 13%. The peak 1 g-average temperature was H = 1.36 ± 0.02 times higher than the radiometric temperature for any media with a thermal conductivity of 0.15-0.50 (W/m)/K, indicating that the radiometer can measure peak 1 g-averaged ΔT in physiologically relevant tissue within ±0.4 °C. Active internal MRI detectors can serve as RF radiometers at the MRI frequency to provide accurate independent measures of local and peak temperature without the artifacts that can accompany MRI thermometry or the extra space needed to accommodate alternative

  13. REVIEW ARTICLE: Photometry, radiometry and 'the candela': evolution in the classical and quantum world

    NASA Astrophysics Data System (ADS)

    Zwinkels, Joanne C.; Ikonen, Erkki; Fox, Nigel P.; Ulm, Gerhard; Rastello, Maria Luisa

    2010-10-01

    The metrological fields of photometry and radiometry and their associated units are closely linked through the current definition of the base unit of luminous intensity—the candela. These fields are important to a wide range of applications requiring precise and accurate measurements of electromagnetic radiation and, in particular, the amount of radiant energy (light) that is perceived by the human eye. The candela has been one of the base units since the inception of the International System of Units (SI) and is the only base unit that quantifies a fundamental biological process—human vision. This photobiological process spans an enormous dynamic range of light levels from a few-photon interaction involved in triggering the vision mechanism to a level of more than 1015 photons per second that is accommodated by the visual response under bright daylight conditions. This position paper, prepared by members of the Task Group on the SI of the Consultative Committee for Photometry and Radiometry Strategic Planning Working Group (CCPR WG-SP), reviews the evolution of these fields of optical radiation measurements and their consequent impact on definitions and realization of the candela. Over the past several decades, there have been significant developments in sources, detectors, measuring instruments and techniques, that have improved the measurement of photometric and radiometric quantities for classical applications in lighting design, manufacturing and quality control processes involving optical sources, detectors and materials. These improved realizations largely underpin the present (1979) definition of the candela. There is no consensus on whether this radiant-based definition fully satisfies the current and projected needs of the optical radiation community. There is also no consensus on whether a reformulation of the definition of the candela in terms of photon flux will be applicable to the lighting community. However, there have been significant recent

  14. Cassini SAR, radiometry, scatterometry and altimetry observations of Titan's dune fields

    USGS Publications Warehouse

    Le, Gall A.; Janssen, M.A.; Wye, L.C.; Hayes, A.G.; Radebaugh, J.; Savage, C.; Zebker, H.; Lorenz, R.D.; Lunine, J.I.; Kirk, R.L.; Lopes, R.M.C.; Wall, S.; Callahan, P.; Stofan, E.R.; Farr, Tom

    2011-01-01

    Large expanses of linear dunes cover Titan's equatorial regions. As the Cassini mission continues, more dune fields are becoming unveiled and examined by the microwave radar in all its modes of operation (SAR, radiometry, scatterometry, altimetry) and with an increasing variety of observational geometries. In this paper, we report on Cassini's radar instrument observations of the dune fields mapped through May 2009 and present our key findings in terms of Titan's geology and climate. We estimate that dune fields cover ???12.5% of Titan's surface, which corresponds to an area of ???10millionkm2, roughly the area of the United States. If dune sand-sized particles are mainly composed of solid organics as suggested by VIMS observations (Cassini Visual and Infrared Mapping Spectrometer) and atmospheric modeling and supported by radiometry data, dune fields are the largest known organic reservoir on Titan. Dune regions are, with the exception of the polar lakes and seas, the least reflective and most emissive features on this moon. Interestingly, we also find a latitudinal dependence in the dune field microwave properties: up to a latitude of ???11??, dune fields tend to become less emissive and brighter as one moves northward. Above ???11?? this trend is reversed. The microwave signatures of the dune regions are thought to be primarily controlled by the interdune proportion (relative to that of the dune), roughness and degree of sand cover. In agreement with radiometry and scatterometry observations, SAR images suggest that the fraction of interdunes increases northward up to a latitude of ???14??. In general, scattering from the subsurface (volume scattering and surface scattering from buried interfaces) makes interdunal regions brighter than the dunes. The observed latitudinal trend may therefore also be partially caused by a gradual thinning of the interdunal sand cover or surrounding sand sheets to the north, thus allowing wave penetration in the underlying

  15. Monitoring local heating around an interventional MRI antenna with RF radiometry

    SciTech Connect

    Ertürk, M. Arcan; El-Sharkawy, AbdEl-Monem M.; Bottomley, Paul A.

    2015-03-15

    Purpose: Radiofrequency (RF) radiometry uses thermal noise detected by an antenna to measure the temperature of objects independent of medical imaging technologies such as magnetic resonance imaging (MRI). Here, an active interventional MRI antenna can be deployed as a RF radiometer to measure local heating, as a possible new method of monitoring device safety and thermal therapy. Methods: A 128 MHz radiometer receiver was fabricated to measure the RF noise voltage from an interventional 3 T MRI loopless antenna and calibrated for temperature in a uniformly heated bioanalogous gel phantom. Local heating (ΔT) was induced using the antenna for RF transmission and measured by RF radiometry, fiber-optic thermal sensors, and MRI thermometry. The spatial thermal sensitivity of the antenna radiometer was numerically computed using a method-of-moment electric field analyses. The gel’s thermal conductivity was measured by MRI thermometry, and the localized time-dependent ΔT distribution computed from the bioheat transfer equation and compared with radiometry measurements. A “H-factor” relating the 1 g-averaged ΔT to the radiometric temperature was introduced to estimate peak temperature rise in the antenna’s sensitive region. Results: The loopless antenna radiometer linearly tracked temperature inside a thermally equilibrated phantom up to 73 °C to within ±0.3 °C at a 2 Hz sample rate. Computed and MRI thermometric measures of peak ΔT agreed within 13%. The peak 1 g-average temperature was H = 1.36 ± 0.02 times higher than the radiometric temperature for any media with a thermal conductivity of 0.15–0.50 (W/m)/K, indicating that the radiometer can measure peak 1 g-averaged ΔT in physiologically relevant tissue within ±0.4 °C. Conclusions: Active internal MRI detectors can serve as RF radiometers at the MRI frequency to provide accurate independent measures of local and peak temperature without the artifacts that can accompany MRI thermometry or

  16. Atomic oxygen, atomic hydrogen, and chemical heating rates derived from SABER

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.

    The SABER instrument on the TIMED satellite measures the infrared OH airglow at 2.0 um in the terrestrial mesosphere. These measurements are inverted to provide the volume emissions rates of the OH(9-7 + 8-6) bands. These high-lying bands are formed directly upon the reaction of atomic hydrogen and ozone and thus the measured volume emission rate is a direct measure of the rate of reaction. The SABER OH emission rates and the measured SABER ozone are used to derive the concentration of atomic hydrogen in the mesopause region. The emission rate is also a direct measure of the rate of energy deposition due to the reaction of atomic hydrogen and ozone. Rates of chemical heating are then readily derived upon provision of atmospheric temperature and density from SABER. Under the assumption of photochemical steady state in the production and loss of ozone, the emission rates can also be used to derive atomic oxygen. The abundances of H and O enable the computation of rates of chemical heating due to numerous exothermic reactions. A key to these derivations lies in the knowledge of the rate of quenching/reaction of vibrationally excited OH with atomic oxygen. We present the SABER airglow models, data inversion approach, and results for O, H, and chemical heating.

  17. Differential thermal wave radiometry for noninvasive blood glucose monitoring: feasibility analysis

    NASA Astrophysics Data System (ADS)

    Telenkov, Sergey A.

    2004-04-01

    Blood glucose monitoring is essential for management of diabetes especially for those patients who requires regular insulin injections. A reliable noninvasive technique may eliminate inconvenience associated with frequent skin puncture to draw blood for measurement by a standard meter. Laser-induced thermal waves in tissue and detection of resulting IR response may provide a valuable approach to development of noninvasive glucose sensor. The present report analyzes radiometric response of tissue at the two wavelengths in mid-IR spectral band with phase-sensitive detection to evaluate feasibility of differential phase radiometry for noninvasive glucose monitoring. Sensitivity of the differential phase method is computed using two models of laser-tissue interaction: homogeneous light absorption and a discrete chromophore heating.

  18. Study of the heat transfer in solids using infrared photothermal radiometry and simulation by COMSOL Multiphysics.

    PubMed

    Suarez, V; Hernández Wong, J; Nogal, U; Calderón, A; Rojas-Trigos, J B; Juárez, A G; Marín, E

    2014-01-01

    It is reported the study of the heat transfer through a homogeneous and isotropic solid exited by square periodic light beam on its front surface. For this, we use the Infrared Photothermal Radiometry in order to obtain the evolution of the temperature difference on the rear surface of three samples, silicon, copper and wood, as a function of the exposure time. Also, we solved the heat transport equation for this problem with the boundary conditions congruent with the physical situation, by means of numerical simulation based in finite element analysis. Our results show a good agreement between the experimental and numerical simulated results, which demonstrate the utility of this methodology for the study of the thermal response of solids.

  19. Photothermal radiometry and modulated luminescence examination of demineralized and remineralized dental lesions

    NASA Astrophysics Data System (ADS)

    Hellen, A.; Mandelis, A.; Finer, Y.

    2010-03-01

    Dental caries involves continuous challenges of acid-induced mineral loss and a counteracting process of mineral recovery. As an emerging non-destructive methodology, photothermal radiometry and modulated luminescence (PTR-LUM) has shown promise in measuring changes in tooth mineral content. Human molars (n=37) were subjected to demineralization in acid gel (pH 4.5, 10 days), followed by incubation in remineralisation solutions (pH 6.7, 4 weeks) without or with fluoride (1 or 1000 ppm). PTR-LUM frequency scans (1 Hz - 1 kHz) were performed prior to and during demineralization and remineralization treatments. Transverse Micro-Radiography (TMR) analysis followed at treatment conclusion. The non-fluoridated group exhibited opposite amplitude and phase trends to those of the highly fluoridated group: smaller phase lag and larger amplitude. These results point to a complex interplay between surface and subsurface processes during remineralization, confining the thermal-wave centroid toward the dominating layer.

  20. Propagation of nonparaxial partially coherent fields across interfaces using generalized radiometry.

    PubMed

    Petruccelli, Jonathan C; Alonso, Miguel A

    2009-09-01

    A radiometric framework is described for modeling the propagation of nonparaxial scalar fields of any degree of coherence past planar boundaries (or composite interfaces) between homogeneous, isotropic nonabsorptive media in three dimensions. The transformation is shown to be, to lowest order, that predicted by classical radiometry but potentially including a Goos-Hänchen shift. Higher-order corrections take the form of coefficients multiplied by derivatives of the basic estimate. The accuracy of the radiometric term, along with second-order derivative corrections, are examined for Gaussian Schell-model fields of varying width and states of coherence. This technique is found to work well for most such fields but to fail in reflection for fields with significant total-internally-reflected components.

  1. Capturing a failure of an ASIC in-situ, using infrared radiometry and image processing software

    NASA Technical Reports Server (NTRS)

    Ruiz, Ronald P.

    2003-01-01

    Failures in electronic devices can sometimes be tricky to locate-especially if they are buried inside radiation-shielded containers designed to work in outer space. Such was the case with a malfunctioning ASIC (Application Specific Integrated Circuit) that was drawing excessive power at a specific temperature during temperature cycle testing. To analyze the failure, infrared radiometry (thermography) was used in combination with image processing software to locate precisely where the power was being dissipated at the moment the failure took place. The IR imaging software was used to make the image of the target and background, appear as unity. As testing proceeded and the failure mode was reached, temperature changes revealed the precise location of the fault. The results gave the design engineers the information they needed to fix the problem. This paper describes the techniques and equipment used to accomplish this failure analysis.

  2. Depth determination of chromophores in human skin by pulsed photothermal radiometry

    SciTech Connect

    Milner, T.E. |; Smithies, D.J.; Goodman, D.M.; Nelson, J.S. |; Goodman, D.M.; Lau, A.

    1996-07-01

    We report on the application of pulsed photothermal radiometry (PPTR) to determine the depth of {ital in}-{ital vitro} and {ital in}-{ital vivo} subsurface chromophores in biological materials. Measurements provided by PPTR in combination with a nonnegative constrained conjugate-gradient algorithm are used to determine the initial temperature distribution in a biological material immediately following pulsed laser irradiation. Within the experimental error, chromophore depths (50{endash}450 {mu}m) in 55 {ital in}-{ital vitro} collagen phantoms determined by PPTR and optical low-coherence reflectometry are equivalent. The depths of port-wine-stain blood vessels determined by PPTR correlate very well with their locations found by computer-assisted microscopic observation of histologic sections. The mean blood-vessel depth deduced from PPTR and histologic observation is statistically indistinguishable ({ital p}{lt}0.94). {copyright} {ital 1996 Optical Society of America.}

  3. The use of undulator radiation in VUV and soft x-ray radiometry

    SciTech Connect

    Kincaid, B.M.

    1991-11-01

    A new generation of synchrotron radiation light sources covering the VUV, soft x-ray and hard x-ray and spectral regions is under construction in several countries, designed specifically to use periodic magnetic undulators and low-emittance electron or positron beams to produce high-brightness near-diffraction-limited synchrotron radiation beams. It should be possible to use specially designed undulators and wigglers in the new synchrotron light facilities as tunable narrow band radiometric sources in the VUV and soft x-ray regions. An introduction to the physics of undulator radiation is followed by a discussion of some of the consequences of maximizing source performance, including high beam power, harmonics, optics contamination, and the unusual spectral and angular properties of undulator radiation. The limitations of the presently planned undulators as radiometric sources and the design criteria for a possible radiometry undulator will be discussed.

  4. Determination of radii of satellites and asteroids from radiometry and photometry.

    NASA Technical Reports Server (NTRS)

    Morrison, D.

    1973-01-01

    Visual photometry, which measures reflected solar radiation, can be combined with infrared radiometry, which measures absorbed and reradiated solar energy, to determine the albedo and hence the radius of small solar system objects. Equations and graphical solutions for radius and albedo are presented for cases where the object is at opposition, in equilibrium with the insolation, and has unit values for phase integral and infrared emissivities. Each of these assumptions is then discussed, and expressions are given for the dependence of the derived parameters on the assumptions. The Galilean satellites, whose radii are well known, provide a calibration of this technique. Applications are then discussed to Saturn's satellites Iapetus and Rhea and to asteroids (1) Ceres, (4) Vesta, and (324) Bamberga. It is shown that the technique is not subject to major systematic errors and that it is possible to derive radii, particularly for dark objects, with uncertainties of less than 10%.

  5. Quantitative characterization of traumatic bruises by combined pulsed photothermal radiometry and diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Vidovič, Luka; Milanič, Matija; Randeberg, Lise L.; Majaron, Boris

    2015-02-01

    We apply diffuse reflectance spectroscopy (DRS) and pulsed photothermal radiometry (PPTR) for characterization of the bruise evolution process. While DRS provides information in a wide range of visible wavelengths, the PPTR enables extraction of detailed depth distribution and concentration profiles of selected absorbers (e.g. melanin, hemoglobin). In this study, we simulate experimental DRS spectra and PPTR signals using the Monte Carlo technique and focus on characterization of a suitable fitting approach for their analysis. We find inverse Monte Carlo to be superior to the diffusion approximation approach for the inverse analysis of DRS spectra. The analysis is then augmented with information obtainable by the fitting of the PPTR signal. We show that both techniques can be coupled in a combined fitting approach. The combining of two complementary techniques improves the robustness and accuracy of the inverse analysis, enabling a comprehensive quantitative characterization of the bruise evolution dynamics.

  6. A Cryogenic Radiometry Based Spectral Responsivity Scale at the National Metrology Centre

    NASA Astrophysics Data System (ADS)

    Xu, Gan; Huang, Xuebo

    This paper describes the spectral responsivity scale established at the National Metrology Centre (NMC) based on cryogenic radiometry. A primary standard - a mechanically pumped cryogenic radiometer together with a set of intensity-stabilised lasers provides traceability for optical power measurement with an uncertainty in the order of 10-4 at 14 discrete wavelengths in the spectral range from 350 nm to 800 nm. A silicon trap detector, with its absolute responsivity calibrated against the cryogenic radiometer is used as a transfer standard for the calibration of other detectors using a specially built spectral comparator. The relative spectral responsivity of a detector at other wavelengths can be determined through the use of a cavity pyroelectric detector and the extrapolation technique. With this scale, NMC is capable to calibrate the spectral responsivity of different type of photo detectors from 250 nm to 1640 nm with an uncertainty range from 3.7% to 0.3%.

  7. Depth determination of chromophores in human skin by pulsed photothermal radiometry

    NASA Astrophysics Data System (ADS)

    Milner, Thomas E.; Smithies, Derek J.; Goodman, Dennis M.; Nelson, J. Stuart; Goodman, Dennis M.; Lau, Alice

    1996-07-01

    We report on the application of pulsed photothermal radiometry (PPTR) to determine the depth of in-vitro and in-vivo subsurface chromophores in biological materials. Measurements provided by PPTR in combination with a nonnegative constrained conjugate-gradient algorithm are used to determine the initial temperature distribution in a biological material immediately following pulsed laser irradiation. Within the experimental error, chromophore depths (50-450 mu m) in 55 in-vitro collagen phantoms determined by PPTR and optical low-coherence reflectometry are equivalent. The depths of port-wine-stain blood vessels determined by PPTR correlate very well with their locations found by computer-assisted microscopic observation of histologic sections. The mean blood-vessel depth deduced from PPTR and histologic observation is statistically indistinguishable (p greater than 0.94).

  8. Opto-Thermal Transient Emission Radiometry (OTTER) to image diffusion in nails in vivo.

    PubMed

    Xiao, P; Zheng, X; Imhof, R E; Hirata, K; McAuley, W J; Mateus, R; Hadgraft, J; Lane, M E

    2011-03-15

    This work describes the first application of Opto-Thermal Transient Emission Radiometry (OTTER), an infrared remote sensing technique, to probe the extent to which solvents permeate the human nail in vivo. Decanol, glycerol and butyl acetate were selected as model solvents. After application of the solvents, individually, to human volunteers, OTTER was used to depth profile the solvents. The permeation rate of the solvents was ranked as glycerol>decanol>butyl acetate. It is possible that some of the butyl acetate may have evaporated during the experiment. The ability of decanol to extract lipids from biological tissue is also considered. These preliminary results demonstrate the potential of OTTER as a tool to identify optimal excipients with which to target drugs to the nail. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Proposed Definitions of Some Technical Terms Frequently Used in Microwave Radiometry for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Shiue, James C.; Zukor, Dorothy J. (Technical Monitor)

    2000-01-01

    The use of microwave radiometry for remote sensing is a relatively young field. As a result, there are no standard definitions of many frequently used technical terms; a lot of which are conventional usages carried-over from optical remote sensing, and a lot more are shared with electrical or microwave engineering. Sometimes the divergent notions and assumptions originating from a different field may cause ambiguity or confusions. It is proposed that we establish a list of frequently used terms, together with their 'standard' definitions and hope that they will gradually gain general acceptance by the remote sensing community. It would be even more useful if the IEEE community can set up a standard committee of sort to develop and maintain the standards. To minimize the effort, the existing terms should be kept or reinterpreted as much as possible. For example, the term 'Instantaneous Field of View' (IFOV), originally coming from the optical remote sensing field, is now appearing in microwave remote sensing literature frequently. The IFOV refers to the 'beam width' or the 'diameter' of the beam's geometrical projection on earth surface. Since the definition of 'beam width' is different for an optical system versus a microwave antenna, the use of IFOV in microwave radiometry needed to be clarified. Also, the meaning of the IFOV will be different depending upon whether the beam is scanning or not, and how the scanning takes place, e.g. 'continuous scanning' vs 'stare-and-step scan.' From this one term alone, it is clear that more subtle meanings must be spell out in detail and a 'standard' definition would help in understanding and comparing systems and data in the literature. A selected list of terms with their suggested definitions will be discussed in this presentation.

  10. I. R. emission measurements of shocked rocket propellants by time-resolved infrared radiometry

    SciTech Connect

    Von Holle, W.G.

    1983-02-14

    This report is a summary of the results of the application of time-resolved radiometry to the study of SDT in VRP, VOY, FKM and ALTU-16. Some of the data have been previously reported. An attempt is made to integrate and correlate all the data in order to arrive at conclusions about the effect of the composition of these propellants on their response to shock stimulus. These propellants were chosen to represent extremes of sensitivity and composition. After a brief description of the gun experiments, the bare propellants results are discussed, followed by KCl overlay experiments. Finally, shredded VRO-2B gun-impact experiments which were done to elucidate the nature of the reactions occurring in porous systems, important for understanding DDT and XDT, are described. Results of infrared radiometry experiments have provided time-resolved temperature and fraction reacted data for a series of shocked propellants with different composition. Results on free surfaces demonstrated the heterogeneity of shock-induced reaction and indicated a wide range of responses. VOY and FKM were found to be highly reactive; VRP and ALTU-16 almost inert. KCl crystal confined experiments allowed the heterogeneity of the shock induced reaction to be confirmed, and the evolution of reaction under pressure was compared to 9404. Confinement smooths the differences between propellants, but VOY remains the standout from the rest.The ordering of shock induced reactivity follows the ordering of calculated HEX and flame temperatures. The KCl experiments show a large early pressure-dependent change in reaction rate which is inconsistent with manganin gauge pressure measurements. The most likely explanation seems to be a rapid binder decomposition reaction, which is highly pressure dependent and which would lead to large pressure increases at longer run distances than available in these experiments.

  11. Studying the MLT by a Combined Analysis of SABER/TIMED and Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Kutepov, A. A.; Pesnell, W. D.; Goldberg, R. A.; Zecha, M.; Gerding, M.; Luebken, F. J.; Fiedler, J.; vonZhan, U.; Russell, J. M., III

    2006-01-01

    The SABER instrument on board the TIMED Satellite is a limb scanning infrared radiometer designed to measure temperature and minor constituent vertical profiles and energetics parameters in the mesosphere and lower thermosphere (MLT). The measurements have been performed continuously since January 25, 2002 to provide excellent coverage for both hemispheres. The Leibniz-Institute of Atmospheric Physics (LAP) at Kuehlungsborn, Germany (54N, 12E) operates two lidar instruments, using three different temperature measurement methods, optimized for three altitude ranges. The total altitude range of the lidar installation lies from 1 to 105 km. Another instrument used for intercomparison is the ALOMAR RMR lidar, located at Andoya, Norway (69N, 16E). We have searched the SABER and lidar datasets for coincidental common volume measurements within plus or minus 1 degree in latitude, plus or minus 2 degrees in longitude and approx. 1 hour in time for the sake of (a) comparison of measured temperatures; (b) validation of the models used in SABER data analysis; and (c) extracting new information about MLT parameters. In this work we applied the non-LTE ALI-ARMS code designed to calculate the nonequilibrium radiance in different viewing geometries to the analysis of measurements which satisfied these search criteria. The results of this analysis (a) support the application of higher value of CO2-O quenching rate (6e-12 cubic centimeters per second) by the non-LTE temperature retrievals from the SABER 15 micrometer limb radiance data, and (b) demonstrate the importance of accounting for the vibrational-vibrational energy exchange among the CO2 isotopes for accurate temperature retrievals. Using temperature profiles obtained in lidar measurements as inputs for the retrieval algorithm we also retrieved the nighttime CO2 densities from the SABER 15 micrometer limb radiances and compared them with the model and climatology CO2 data used in the SABER nighttime temperature retrievals.

  12. Studying the MLT by a Combined Analysis of SABER/TIMED and Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Kutepov, A. A.; Pesnell, W. D.; Goldberg, R. A.; Zecha, M.; Gerding, M.; Luebken, F. J.; Fiedler, J.; vonZhan, U.; Russell, J. M., III

    2006-01-01

    The SABER instrument on board the TIMED Satellite is a limb scanning infrared radiometer designed to measure temperature and minor constituent vertical profiles and energetics parameters in the mesosphere and lower thermosphere (MLT). The measurements have been performed continuously since January 25, 2002 to provide excellent coverage for both hemispheres. The Leibniz-Institute of Atmospheric Physics (LAP) at Kuehlungsborn, Germany (54N, 12E) operates two lidar instruments, using three different temperature measurement methods, optimized for three altitude ranges. The total altitude range of the lidar installation lies from 1 to 105 km. Another instrument used for intercomparison is the ALOMAR RMR lidar, located at Andoya, Norway (69N, 16E). We have searched the SABER and lidar datasets for coincidental common volume measurements within plus or minus 1 degree in latitude, plus or minus 2 degrees in longitude and approx. 1 hour in time for the sake of (a) comparison of measured temperatures; (b) validation of the models used in SABER data analysis; and (c) extracting new information about MLT parameters. In this work we applied the non-LTE ALI-ARMS code designed to calculate the nonequilibrium radiance in different viewing geometries to the analysis of measurements which satisfied these search criteria. The results of this analysis (a) support the application of higher value of CO2-O quenching rate (6e-12 cubic centimeters per second) by the non-LTE temperature retrievals from the SABER 15 micrometer limb radiance data, and (b) demonstrate the importance of accounting for the vibrational-vibrational energy exchange among the CO2 isotopes for accurate temperature retrievals. Using temperature profiles obtained in lidar measurements as inputs for the retrieval algorithm we also retrieved the nighttime CO2 densities from the SABER 15 micrometer limb radiances and compared them with the model and climatology CO2 data used in the SABER nighttime temperature retrievals.

  13. Single-frequency and multiband microwave radiometry for feasible brain conductivity variation imaging during reactions to external stimuli

    NASA Astrophysics Data System (ADS)

    Karanasiou, I. S.; Uzunoglu, N. K.

    2006-12-01

    Recent research results imply that microwave radiometry may exhibit the capability of detecting local variations of the conductivity attributes of the media under measurement. The contactless measurements in question are a function of the geometrical spatial properties of a newly developed microwave radiometry imaging system (MiRaIS), comprising an ellipsoidal conductive wall cavity. The proposed methodology is based on single-frequency and multiband microwave radiometry in conjunction with the implementation of an ellipsoidal reflector to achieve focusing on the areas of interest. The theoretical fundamentals as well as an overview of the system modules and past experimental results are herein presented, forming the background and context on which current and future research is based. Experimentation using small water phantoms in order to verify the system's focusing properties and saline solution phantoms in order to investigate the system's capability of sensing conductivity changes at various microwave frequencies with a sensitive multiband receiver has been conducted. The results show that local resistance variations in small phantoms can be detected at microwave frequencies by the MiRaIS. Combining these experimental data with previous human experimental results, the feasibility of brain conductivity variation imaging during reactions to external stimuli by the proposed system is examined and discussed in the present paper.

  14. Ozone and temperature decadal responses to solar variability in the stratosphere and lower mesosphere, based on measurements from SABER on TIMED

    NASA Astrophysics Data System (ADS)

    Huang, Frank T.; Mayr, Hans G.; Russell, James M., III; Mlynczak, Martin G.

    2016-09-01

    We have derived ozone and temperature responses to solar variability over a solar cycle, from 2002 to 2014 at 20-60 km and 48° S-48° N, based on data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite. Simultaneous results for ozone and temperature with this kind of spatial coverage have not been previously available, and they provide the opportunity to study correlations between ozone and temperature responses. In previous studies, there has not been general agreement on the details or, at times, even the broad behavior of the responses to decadal solar variability. New results from a different dataset should supply new information on this important and interesting subject. A multiple regression is applied to obtain responses as a function of the solar 10.7 cm flux. Positive responses mean that they are larger at solar maximum than at solar minimum of the solar cycle. Both ozone and temperature responses are found be positive or negative, depending on location. Generally, from ˜ 25 to 60 km, the ozone and temperature responses are mostly out of phase (negatively correlated) with each other as a function of solar variability, with some exceptions in the lower altitudes. These negative correlations are maintained even though the individual ozone (temperature) responses can change signs as a function of altitude and latitude, because the corresponding temperature (ozone) responses change signs in step with each other. From ˜ 50 to 60 km, ozone responses are relatively small, varying from ˜ -1 to ˜ 2 % 100 sfu-1 (solar flux units), while temperature responses can approach ˜ 2 °K 100 sfu-1. From ˜ 25 to ˜ 40 km, the ozone responses have become mostly positive at all latitudes and approach a maximum of ˜ 5 % 100 sfu-1 near the Equator and ˜ 30-35 km. In contrast, at low latitudes, the temperature responses have become negative but also

  15. Lunar Phase Function at 1064 Nm from Lunar Orbiter Laser Altimeter Passive and Active Radiometry

    NASA Technical Reports Server (NTRS)

    Barker, M. K.; Sun, X.; Mazarico, E.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

    2016-01-01

    We present initial calibration and results of passive radiometry collected by the Lunar Orbiter Laser Altimeter onboard the Lunar Reconnaissance Orbiter over the course of 12 months. After correcting for time- and temperature-dependent dark noise and detector responsivity variations, the LOLA passive radiometry measurements are brought onto the absolute radiance scale of the SELENE Spectral Profiler. The resulting photometric precision is estimated to be 5%. We leverage the unique ability of LOLA to measure normal albedo to explore the 1064 nm phase function's dependence on various geologic parameters. On a global scale, we find that iron abundance and optical maturity (quantified by FeO and OMAT) are the dominant controlling parameters. Titanium abundance (TiO2), surface roughness on decimeter to decameter scales, and soil thermo- physical properties have a smaller effect, but the latter two are correlated with OMAT, indicating that exposure age is the driving force behind their effects in a globally-averaged sense. The phase function also exhibits a dependence on surface slope at approximately 300 m baselines, possibly the result of mass wasting exposing immature material and/or less space weathering due to reduced sky visibility. Modeling the photometric function in the Hapke framework, we find that, relative to the highlands, the maria exhibit decreased backscattering, a smaller opposition effect (OE) width, and a smaller OE amplitude. Immature highlands regolith has a higher backscattering fraction and a larger OE width compared to mature highlands regolith. Within the maria, the backscattering fraction and OE width show little dependence on TiO2 and OMAT. Variations in the phase function shape at large phase angles are observed in and around the Copernican-aged Jackson crater, including its dark halo, a putative impact melt deposit. Finally, the phase function of the Reiner Gamma Formation behaves more optically immature than is typical for its composition

  16. Lunar phase function at 1064 nm from Lunar Orbiter Laser Altimeter passive and active radiometry

    NASA Astrophysics Data System (ADS)

    Barker, M. K.; Sun, X.; Mazarico, E.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

    2016-07-01

    We present initial calibration and results of passive radiometry collected by the Lunar Orbiter Laser Altimeter onboard the Lunar Reconnaissance Orbiter over the course of 12 months. After correcting for time- and temperature-dependent dark noise and detector responsivity variations, the LOLA passive radiometry measurements are brought onto the absolute radiance scale of the SELENE Spectral Profiler. The resulting photometric precision is estimated to be ∼5%. We leverage the unique ability of LOLA to measure normal albedo to explore the 1064 nm phase function's dependence on various geologic parameters. On a global scale, we find that iron abundance and optical maturity (quantified by FeO and OMAT) are the dominant controlling parameters. Titanium abundance (TiO2), surface roughness on decimeter to decameter scales, and soil thermophysical properties have a smaller effect, but the latter two are correlated with OMAT, indicating that exposure age is the driving force behind their effects in a globally-averaged sense. The phase function also exhibits a dependence on surface slope at ∼300 m baselines, possibly the result of mass wasting exposing immature material and/or less space weathering due to reduced sky visibility. Modeling the photometric function in the Hapke framework, we find that, relative to the highlands, the maria exhibit decreased backscattering, a smaller opposition effect (OE) width, and a smaller OE amplitude. Immature highlands regolith has a higher backscattering fraction and a larger OE width compared to mature highlands regolith. Within the maria, the backscattering fraction and OE width show little dependence on TiO2 and OMAT. Variations in the phase function shape at large phase angles are observed in and around the Copernican-aged Jackson crater, including its dark halo, a putative impact melt deposit. Finally, the phase function of the Reiner Gamma Formation behaves more optically immature than is typical for its composition and OMAT

  17. IAP RAS microwave radiometry complex: sounding atmospheric thermal structure from the ground up to 55km.

    NASA Astrophysics Data System (ADS)

    Belikovich, Mikhail; Shvetsov, Alexander; Ryskin, Vitaly; Mukhin, Dmitry; Kulikov, Mikhail; Feigin, Alexander

    2016-04-01

    Thermal structure is the key characteristic of the atmosphere. Depending on the altitude, it is measured by different methods. In troposphere a plethora of in-situ techniques exists while in middle atmosphere remote sensing is primary type of measurement. The remote sensing is conducted in different wavelengths: optical, infrared and microwave. Satellite based measurements are the most popular kind of remote sensing measurements as it provides global coverage. Ground based passive microwave remote sensing technique has its place when one need permanent monitoring with high time resolution in order to study short-term local events like gravity waves. Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS) develops multi-purpose radiometry complex for constant atmospheric monitoring. For now, it measures temperature profiles from ground to 55km, tropospheric water vapor and ozone. It consists of several radiometers with spectral bands ranging from 20 to 112 GHz. In 2015 two radiometers were added in order to measure thermal structure at surface level and troposphere: scanning device operating in 55-59GHz, and device at 50-55GHz. The change led to modifying the retrieval software. The work presents the description of the radiometry complex and corresponding retrieval software. The main part is devoted to new radiometers and enhancements in retrieval procedure. The retrieval algorithms are described: for each device separately and for the whole temperature retrieval part of the complex. The use of the single procedure for the group of radiometers helps to merge the profile with each other correctly. The main issue of the single procedure (numerical complexity aside) is dealing with the possible difference in calibration of the devices. Error analysis of the procedures is conducted. The characteristics of the complex and the retrieval algorithms are presented. The capabilities of the algorithms are shown on simulated and real data; the last one was

  18. Lunar Phase Function at 1064 Nm from Lunar Orbiter Laser Altimeter Passive and Active Radiometry

    NASA Technical Reports Server (NTRS)

    Barker, M. K.; Sun, X.; Mazarico, E.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

    2016-01-01

    We present initial calibration and results of passive radiometry collected by the Lunar Orbiter Laser Al- timeter onboard the Lunar Reconnaissance Orbiter over the course of 12 months. After correcting for time- and temperature-dependent dark noise and detector responsivity variations, the LOLA passive radiometry measurements are brought onto the absolute radiance scale of the SELENE Spectral Profiler. The resulting photometric precision is estimated to be approximately 5%. We leverage the unique ability of LOLA to measure normal albedo to explore the 1064 nm phase function's dependence on various geologic parameters. On a global scale, we find that iron abundance and optical maturity (quantified by FeO and OMAT) are the dominant controlling parameters. Titanium abundance (TiO2 ), surface roughness on decimeter to decameter scales, and soil thermophysical properties have a smaller effect, but the latter two are correlated with OMAT, indicating that exposure age is the driving force behind their effects in a globally-averaged sense. The phase function also exhibits a dependence on surface slope at approximately 300 m baselines, possibly the result of mass wasting exposing immature material and/or less space weathering due to reduced sky visibility. Modeling the photometric function in the Hapke framework, we find that, relative to the highlands, the maria exhibit decreased backscattering, a smaller opposition effect (OE) width, and a smaller OE amplitude. Immature highlands regolith has a higher backscattering fraction and a larger OE width compared to mature highlands regolith. Within the maria, the backscattering fraction and OE width show little dependence on TiO2 and OMAT. Variations in the phase function shape at large phase angles are observed in and around the Copernican-aged Jackson crater, including its dark halo, a putative impact melt deposit. Finally, the phase function of the Reiner Gamma Formation behaves more optically immature than is typical for its

  19. Reference data for bone mineral density in Swedish women using digital x-ray radiometry.

    PubMed

    Arvidsson, Bo; Bodin, Lennart; Rask, Eva; Schvarcz, Erik; Möller, Margareta

    2013-01-01

    During the last decade, digital X-ray radiometry (DXR) has been used to measure bone mineral density (BMD) in the metacarpal bones. The aim of this study was to establish Swedish reference material for bone mass in women, measured in the metacarpal bones with DXR, and compare these data with the data from the manufacturer. A sample of 1440 women aged 20-79yr living in Örebro County was randomly assigned from the population register. Microdose mammography was used (Sectra MDM L30; Sectra Imtec AB, Linköping, Sweden) to measure BMD. Cole's LMS method was used to calculate DXR. Six hundred sixty-nine (48.3%) women participated. Peak bone mass occurred at the age of 43.4yr with a BMD of 0.597g/cm(2) (standard deviation: 0.050). Our Swedish data correlated well with the manufacturer's material. Only among women aged 50-59yr did BMD differ, where the Swedish sample had lower values. The LMS method can be used to describe the DXR data and provide a more detailed picture of bone density distribution. DXR-BMD in Swedish women aged 20-79yr is equivalent to findings from other studies, showing the same distribution of BMD in most age groups except for ages 50-59yr. Copyright © 2013 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  20. Non-invasive detection of osteoporotic bone loss using photothermal radiometry and modulated luminescence

    NASA Astrophysics Data System (ADS)

    Kwan, Chi-Hang; Matvienko, Anna; Mandelis, Andreas

    2008-02-01

    Osteoporosis is a skeletal disorder characterized by a compromised bone strength predisposing a person to an increased risk of fracture. The early detection of osteoporosis is important to a successful treatment. Current prominent bone densitometry techniques include, among others, Dual Energy X-Ray Absorptiometry (DEXA) and Mechanical Response Tissue Analysis (MRTA). However, DEXA uses ionizing radiation and MRTA results are often unreliable. Simultaneous Photothermal Radiometry (PTR) and Modulated Luminescence (LUM) measurements can be a non-ionizing, noninvasive and reliable alternative to the aforementioned diagnostics techniques. Controlled mineral loss was simulated with sequential etching of a human skull bone. During the experiments, a low-power modulated laser illuminated the sample surface. The absorbed incident optical energy was then re-emitted either non-radiatively, in the form of thermal waves (PTR), or radiatively as lumimescence light emission (LUM). The experimental setup consisted of a semiconductor laser (635 nm, 20 mW), two lock-in amplifiers, a mercury-cadmium-telluride IR detector for PTR, a photodiode for LUM and a computer. A one-dimensional, one-layer theoretical model for LUM and PTR was developed to analyze the experimental data and extract optical and thermal properties of the sample.

  1. Optical coherency of sunphotometry, sky radiometry and lidar measurements during the early phase of Pacific 2001

    NASA Astrophysics Data System (ADS)

    O'Neill, N. T.; Strawbridge, K. B.; Thulasiraman, S.; Zhang, J.; Royer, A.; Freemantle, J.

    2004-11-01

    Passive sunphotometry and sky radiometry data at sites in the Lower Fraser Valley (Langley-Lochiel) and Saturna Island were synchronously acquired with ground-based scanning lidar (Rapid Acquisition Scanning Aerosol Lidar, RASCAL) and airborne lidar (AERosol Imaging Airborne Lidar, AERIAL) during the Pacific 2001 Air Quality Study. The temporal and spatial behavior of these optical measurements is investigated during a pollution event which occurred from 13 to 16 August 2001. A mid-day minimum in lidar-derived extinction to backscatter ratios (Sa) values, was attributed, at least in part, to the relative humidity (RH) induced optical influence of the column integrated fine mode and/or coarse mode particles in the PBL. Systematically larger Sa values predicted by the sunphotometer and sky radiance inversions were hypothesized to be due to differences between the retrieved refractive index and the actual refractive index of the coarse mode. Aerosol optical depth differences were within maximum error bounds (0.02) when comparing the sunphotometry with spatial maps derived from AERIAL transects. Daily temporal trends of optical and microphysical parameters derived from sunphotometry and sky radiance data at this site were consistent with information deduced from the lidar and meteorological data; while the daily aerosol optical depth decrease was clearly associated with particle removal induced by daytime sea-breeze advection, a significant-to-dominant part of this decrease was associated with decreasing RH growth effects on at least one day.

  2. Geological and Structural Patterns on Titan Enhanced Through Cassini's SAR PCA and High-Resolution Radiometry

    NASA Astrophysics Data System (ADS)

    Paganelli, F.; Schubert, G.; Lopes, R. M. C.; Malaska, M.; Le Gall, A. A.; Kirk, R. L.

    2016-12-01

    The current SAR data coverage on Titan encompasses several areas in which multiple radar passes are present and overlapping, providing additional information to aid the interpretation of geological and structural features. We exploit the different combinations of look direction and variable incidence angle to examine Cassini Synthetic Aperture RADAR (SAR) data using the Principal Component Analysis (PCA) technique and high-resolution radiometry, as a tool to aid in the interpretation of geological and structural features. Look direction and variable incidence angle is of particular importance in the analysis of variance in the images, which aid in the perception and identification of geological and structural features, as extensively demonstrated in Earth and planetary examples. The PCA enhancement technique uses projected non-ortho-rectified SAR imagery in order to maintain the inherent differences in scattering and geometric properties due to the different look directions, while enhancing the geometry of surface features. The PC2 component provides a stereo view of the areas in which complex surface features and structural patterns can be enhanced and outlined. We focus on several areas of interest, in older and recently acquired flybys, in which evidence of geological and structural features can be enhanced and outlined in the PC1 and PC2 components. Results of this technique provide enhanced geometry and insights into the interpretation of the observed geological and structural features, thus allowing a better understanding towards the geology and tectonics on Titan.

  3. Photothermal radiometry parametric identifiability theory for reliable and unique nondestructive coating thickness and thermophysical measurements

    NASA Astrophysics Data System (ADS)

    Guo, X.; Mandelis, A.; Tolev, J.; Tang, K.

    2017-03-01

    In this paper, we present a detailed reliability analysis of estimated parameters to a three-layer theoretical model of photothermal radiometry frequency domain signals by applying parameter identifiability conditions from two steel samples coated with ˜10 μm and 20 μm thick ceramic coating, to measure the thermophysical parameters of the coating, such as thermal diffusivity, thermal conductivity, and coating thickness. The three parameters are unique only when their sensitivity coefficients are linearly independent over the range of measurements. The study demonstrates the complexity of the identifiable experimental conditions through identifiability maps (calculated nonidentifiable locations) and sensitivity coefficient plots, even when the three separated parameters are grouped into two parameters. The validation of the reliability analysis theory by comparing the independently measured, with the fitted thicknesses of two coatings under random and optimized conditions, underscore the great importance of identifiability analysis (sensitivity coefficient plots) in the design of experiments for reliable parameter extractions, especially when the number of parameters is greater than the measurement data channels.

  4. Experimental investigation of demineralization and remineralization of human teeth using infrared photothermal radiometry and modulated luminescence

    NASA Astrophysics Data System (ADS)

    Jeon, Raymond J.; Hellen, Adam; Matvienko, Anna; Mandelis, Andreas; Abrams, Stephen H.; Amaechi, Bennett T.

    2008-02-01

    Photothermal radiometry (PTR) and modulated luminescence (LUM) were applied to detect and monitor the demineralization of root and enamel surfaces of human teeth to produce caries lesions and the subsequent remineralization of the produced lesions. The experimental set-up consisted of a semiconductor laser (659 nm, 120 mW), a mercury-cadmium-telluride IR detector for PTR, a photodiode for LUM, and two lock-in amplifiers. A lesion was created on a 1-mm × 4-mm rectangular window, spanning root to enamel surface, using an artificial caries lesion gel to demineralize the tooth surface and create small carious lesions. The samples were subsequently immersed in a remineralization solution. Each sample was examined with PTR/LUM on root and enamel before and after treatment at times from 1 to 10 days of demineralization and 2 to 10 days of remineralization. PTR/LUM signals showed gradual and consistent changes with treatment time. At the completion of the experiments, transverse micro-radiography (TMR) analysis was performed to correlate the PTR/LUM signals to depth of the carious lesions and mineral losses. In this study, TMR showed good correlation with PTR/LUM. It was also found that treatment duration did not correlate well to any technique, PTR/LUM, or TMR, which is indicative of significant variations in demineralization - remineralization rates among different teeth.

  5. Tower-Perturbation Measurements in Above-Water Radiometry. Volume 23

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Zibordi, Giuseppe; Berthon, Jean-Francois; D'Alimonte, Davide; vanderLinde, Dirk; Brown, James W.

    2003-01-01

    This report documents the scientific activities which took place during June 2001 and June 2002 on the Acqua Alta Oceanographic Tower (AAOT) in the northern Adriatic Sea. The primary objective of these field campaigns was to quantify the effect of platform perturbations (principally reflections of sunlight onto the sea surface) on above-water measurements of water-leaving radiances. The deployment goals documented in this report were to: a) collect an extensive and simultaneous set of above- and in-water optical measurements under predominantly clear-sky conditions; b) establish the vertical properties of the water column using a variety of ancillary measurements, many of which were taken coincidently with the optical measurements; and c) determine the bulk properties of the environment using a diversity of atmospheric, biogeochemical, and meteorological techniques. A preliminary assessment of the data collected during the two field campaigns shows the perturbation in above-water radiometry caused by a large offshore structure is very similar to that caused by a large research vessel.

  6. Melanoma thickness measurement in two-layer tissue phantoms using pulsed photothermal radiometry (PPTR)

    NASA Astrophysics Data System (ADS)

    Wang, Tianyi; Qiu, Jinze; Paranjape, Amit; Milner, Thomas E.

    2009-02-01

    Melanoma is a malignant tumor of melanocytes which are found predominantly in skin. Melanoma is one of the rarer types of skin cancer but causes the majority of skin cancer related deaths. The staging of malignant melanoma using Breslow thickness is important because of the relationship to survival rate after five years. Pulsed photothermal radiometry (PPTR) is based on the time-resolved acquisition of infrared (IR) emission from a sample after pulsed laser exposure. PPTR can be used to investigate the relationship between melanoma thickness and detected radiometric temperature using two-layer tissue phantoms. We used a Monte Carlo simulation to mimic light transport in melanoma and employed a three-dimensional heat transfer model to obtain simulated radiometric temperature increase and, in comparison, we also conducted PPTR experiments to confirm our simulation results. Simulation and experimental results show similar trends: thicker absorbing layers corresponding to deeper lesions produce slower radiometric temperature decays. A quantitative relationship exists between PPTR radiometric temperature decay time and thickness of the absorbing layer in tissue phantoms.

  7. Optical layer development for thin films thermal conductivity measurement by pulsed photothermal radiometry

    SciTech Connect

    Martan, J.

    2015-01-15

    Measurement of thermal conductivity and volumetric specific heat of optically transparent thin films presents a challenge for optical-based measurement methods like pulsed photothermal radiometry. We present two approaches: (i) addition of an opaque optical layer to the surface and (ii) approximate correction of the mathematical model to incorporate semitransparency of the film. Different single layer and multilayer additive optical layers were tested. The materials of the optical layers were chosen according to analysis and measurement of their optical properties: emissivity and absorption coefficient. Presented are thermal properties’ measurement results for 6 different thin films with wide range of thermal conductivity in three configurations of surface: as deposited, added Ti layer, and added Ti/TiAlSiN layer. Measurements were done in dependence on temperature from room temperature to 500 °C. The obtained thermal effusivity evolution in time after the laser pulse shows different effects of the surface layers: apparent effusivity change and time delay. Suitability of different measurement configurations is discussed and results of high temperature testing of different optical layers are presented.

  8. Optical side scattering radiometry for high resolution, wide dynamic range longitudinal assessment of optical fibers.

    PubMed

    Sandoghchi, S R; Petrovich, M; Gray, D R; Chen, Y; Wheeler, N V; Bradley, T D; Wong, N H L; Jasion, G T; Hayes, J; Fokoua, E Numkam; Alonso, M B; Mousavi, S M; Richardson, D J; Poletti, F

    2015-10-19

    Current optical reflectometric techniques used to characterize optical fibers have to trade-off longitudinal range with spatial resolution and therefore struggle to provide simultaneously wide dynamic range (>20dB) and high resolution (<10cm). In this work, we develop and present a technique we refer to as Optical Side Scattering Radiometry (OSSR) capable of resolving discrete and distributed scattering properties of fibers along their length with up to 60dB dynamic range and 5cm spatial resolution. Our setup is first validated on a standard single mode telecoms fiber. Then we apply it to a record-length 11km hollow core photonic band-gap fiber (HC-PBGF) the characterization requirements of which lie far beyond the capability of standard optical reflectometric instruments. We next demonstrate use of the technique to investigate and explain the unusually high loss observed in another HC-PBGF and finally demonstrate its flexibility by measuring a HC-PBGF operating at a wavelength of 2µm. In all of these examples, good agreement between the OSSR measurements and other well-established (but more limited) characterization methods, i.e. cutback loss and OTDR, was obtained.

  9. AIS-2 radiometry and a comparison of methods for the recovery of ground reflectance

    NASA Technical Reports Server (NTRS)

    Conel, James E.; Green, Robert O.; Vane, Gregg; Bruegge, Carol J.; Alley, Ronald E.; Curtiss, Brian J.

    1987-01-01

    A field experiment and its results involving Airborne Imaging Spectrometer-2 data are described. The radiometry and spectral calibration of the instrument are critically examined in light of laboratory and field measurements. Three methods of compensating for the atmosphere in the search for ground reflectance are compared. It was found that laboratory determined responsitivities are 30 to 50 percent less than expected for conditions of the flight for both short and long wavelength observations. The combined system atmosphere surface signal to noise ratio, as indexed by the mean response divided by the standard deviation for selected areas, lies between 40 and 110, depending upon how scene averages are taken, and is 30 percent less for flight conditions than for laboratory. Atmospheric and surface variations may contribute to this difference. It is not possible to isolate instrument performance from the present data. As for methods of data reduction, the so-called scene average or log-residual method fails to recover any feature present in the surface reflectance, probably because of the extreme homogeneity of the scene.

  10. Mesoscale monitoring of the soil freeze/thaw boundary from orbital microwave radiometry

    NASA Technical Reports Server (NTRS)

    Ulaby, Fawwaz T.; Dobson, M. Craig; Kuhn, William R.

    1988-01-01

    The fundamental objectives are to test the feasibility of delineating the lateral boundary between frozen and thawed condition in the surface layer of soil from orbital microwave radiometry and secondly to examine the sensitivity of general circulation models to an explicit parameterization of the boundary condition. Physical models were developed to relate emissivity to scene properties and a simulation package was developed to predict brightness temperature as a function of emissivity and physical temperature in order to address issues of heterogeneity, scaling, and scene dynamics. Radiative transfer models were develped for both bare soil surfaces and those obscured by an intervening layer of vegetation or snow. These models relate the emissivity to the physical properties of the soil and to those of the snow or vegetation cover. A SMMR simulation package was developed to evaluate the adequacy of the emission models and the limiting effects of scaling for realistic scenarios incorporating spatially heterogeneous scenes with dynamic moisture and temperature gradients at the pixel scale.

  11. Sensor-independent approach to the vicarious calibration of satellite ocean color radiometry.

    PubMed

    Franz, Bryan A; Bailey, Sean W; Werdell, P Jeremy; McClain, Charles R

    2007-08-01

    The retrieval of ocean color radiometry from space-based sensors requires on-orbit vicarious calibration to achieve the level of accuracy desired for quantitative oceanographic applications. The approach developed by the NASA Ocean Biology Processing Group (OBPG) adjusts the integrated instrument and atmospheric correction system to retrieve normalized water-leaving radiances that are in agreement with ground truth measurements. The method is independent of the satellite sensor or the source of the ground truth data, but it is specific to the atmospheric correction algorithm. The OBPG vicarious calibration approach is described in detail, and results are presented for the operational calibration of SeaWiFS using data from the Marine Optical Buoy (MOBY) and observations of clear-water sites in the South Pacific and southern Indian Ocean. It is shown that the vicarious calibration allows SeaWiFS to reproduce the MOBY radiances and achieve good agreement with radiometric and chlorophyll a measurements from independent in situ sources. We also find that the derived vicarious gains show no significant temporal or geometric dependencies, and that the mission-average calibration reaches stability after approximately 20-40 high-quality calibration samples. Finally, we demonstrate that the performance of the vicariously calibrated retrieval system is relatively insensitive to the assumptions inherent in our approach.

  12. A Bottom-Up Engineered Broadband Optical Nanoabsorber for Radiometry and Energy Harnessing Applications

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Coles, James B.; Megerian, Krikor G.; Eastwood, Michael; Green, Robert O.; Bandaru, Prabhakar R.

    2013-01-01

    Optical absorbers based on vertically aligned multi-walled carbon nanotubes (MWCNTs), synthesized using electric-field assisted growth, are described here that show an ultra-low reflectance, 100X lower compared to Au-black from wavelength lamba approximately 350 nm - 2.5 micron. A bi-metallic Co/Ti layer was shown to catalyze a high site density of MWCNTs on metallic substrates and the optical properties of the absorbers were engineered by controlling the bottom-up synthesis conditions using dc plasma-enhanced chemical vapor deposition (PECVD). Reflectance measurements on the MWCNT absorbers after heating them in air to 400deg showed negligible changes in reflectance which was still low, approximately 0.022 % at lamba approximately 2 micron. In contrast, the percolated structure of the reference Au-black samples collapsed completely after heating, causing the optical response to degrade at temperatures as low as 200deg. The high optical absorption efficiency of the MWCNT absorbers, synthesized on metallic substrates, over a broad spectral range, coupled with their thermal ruggedness, suggests they have promise in solar energy harnessing applications, as well as thermal detectors for radiometry.

  13. Effective interface state effects in hydrogenated amorphous-crystalline silicon heterostructures using ultraviolet laser photocarrier radiometry

    SciTech Connect

    Melnikov, A.; Mandelis, A.; Halliop, B.; Kherani, N. P.

    2013-12-28

    Ultraviolet photocarrier radiometry (UV-PCR) was used for the characterization of thin-film (nanolayer) intrinsic hydrogenated amorphous silicon (i-a-Si:H) on c-Si. The small absorption depth (approximately 10 nm at 355 nm laser excitation) leads to strong influence of the nanolayer parameters on the propagation and recombination of the photocarrier density wave (CDW) within the layer and the substrate. A theoretical PCR model including the presence of effective interface carrier traps was developed and used to evaluate the transport parameters of the substrate c-Si as well as those of the i-a-Si:H nanolayer. Unlike conventional optoelectronic characterization methods such as photoconductance, photovoltage, and photoluminescence, UV-PCR can be applied to more complete quantitative characterization of a-Si:H/c-Si heterojunction solar cells, including transport properties and defect structures. The quantitative results elucidate the strong effect of a front-surface passivating nanolayer on the transport properties of the entire structure as the result of effective a-Si:H/c-Si interface trap neutralization through occupation. A further dramatic improvement of those properties with the addition of a back-surface passivating nanolayer is observed and interpreted as the result of the interaction of the increased excess bulk CDW with, and more complete occupation and neutralization of, effective front interface traps.

  14. Silver halide fiber optic radiometry for temperature monitoring and control of tissues heated by microwave

    NASA Astrophysics Data System (ADS)

    Shenfeld, Ofer; Belotserkovsky, Edward; Goldwasser, Benad; Zur, Albert; Katzir, Abraham

    1993-02-01

    The heating of tissue by microwave radiation has attained a place of importance in various medical fields, such as the treatment of malignancies, urinary retention, and hypothermia. Accurate temperature measurements in these treated tissues is important for treatment planning and for the control of the heating process. It is also important to be able to measure spacial temperature distribution in the tissues because they are heated in a nonuniform way by the microwave radiation. Conventional temperature sensors used today are inaccurate in the presence of microwave radiation and require contact with the heated tissue. Fiber optic radiometry makes it possible to measure temperatures accurately in the presence of microwave radiation and does not require contact with the tissue. Accurate temperature measurements of tissues heated by microwave was obtained using a silver halide optic radiometer, enabling control of the heating process in other regions of the tissue samples. Temperature mappings of the heated tissues were performed and the nonuniform temperature distributions in these tissues was demonstrated.

  15. A Bottom-Up Engineered Broadband Optical Nanoabsorber for Radiometry and Energy Harnessing Applications

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B.; Coles, James B.; Megerian, Krikor G.; Eastwood, Michael; Green, Robert O.; Bandaru, Prabhakar R.

    2013-01-01

    Optical absorbers based on vertically aligned multi-walled carbon nanotubes (MWCNTs), synthesized using electric-field assisted growth, are described here that show an ultra-low reflectance, 100X lower compared to Au-black from wavelength lamba approximately 350 nm - 2.5 micron. A bi-metallic Co/Ti layer was shown to catalyze a high site density of MWCNTs on metallic substrates and the optical properties of the absorbers were engineered by controlling the bottom-up synthesis conditions using dc plasma-enhanced chemical vapor deposition (PECVD). Reflectance measurements on the MWCNT absorbers after heating them in air to 400deg showed negligible changes in reflectance which was still low, approximately 0.022 % at lamba approximately 2 micron. In contrast, the percolated structure of the reference Au-black samples collapsed completely after heating, causing the optical response to degrade at temperatures as low as 200deg. The high optical absorption efficiency of the MWCNT absorbers, synthesized on metallic substrates, over a broad spectral range, coupled with their thermal ruggedness, suggests they have promise in solar energy harnessing applications, as well as thermal detectors for radiometry.

  16. Development and characterization of integrating sphere for photometry and radiometry measurement

    NASA Astrophysics Data System (ADS)

    Wibawa, Bambang Mukti; Mujahid, Abdul Al; Mindara, Jajat Yuda; Panatarani, Camellia; Joni, I. Made; Siregar, Rustam Efendi

    2013-09-01

    Integrating Sphere (IS) is an instrument formed a cavity sphere with its inner surface act as a Lambertian reflector. IS is needed in many optical measurements which involves a high diffused reflection. In addition, IS very essential in photometry and radiometry measurement system. However, currently, IS is still an imported product which considered very expensive. The material for the sphere and inner surface coating affect the performance of the IS systems. Therefore, the main challenges in designing IS are the material engineering for the sphere and the procedure for the inner surface coating. The inner surface was coated using BaSO4 which has a low absorption and high diffuse reflection. Spectral responses of the IS system was characterized using USB2000+ and calibrated using a standard Spectralon from ocean optic. The obtained IS system used an inner surface coating from a mixed 80% Barium Sulfate (BaSO4) and 20% Nippon Elastex paint which yield a reflection factor ρ = 0.955 and amplification factor M=10.69. The validation was conducted using an emitter with known specification from Luxeon of LXHL-DW01 which produced light flux 40.5 lumen with injection current 350 mA and junction temperature Tj 25°C.

  17. Geodesy by radio interferometry - Water vapor radiometry for estimation of the wet delay

    NASA Technical Reports Server (NTRS)

    Elgered, G.; Davis, J. L.; Herring, T. A.; Shapiro, I. I.

    1991-01-01

    An important source of error in VLBI estimates of baseline length is unmodeled variations of the refractivity of the neutral atmosphere along the propagation path of the radio signals. This paper presents and discusses the method of using data from a water vapor radiomete (WVR) to correct for the propagation delay caused by atmospheric water vapor, the major cause of these variations. Data from different WVRs are compared with estimated propagation delays obtained by Kalman filtering of the VLBI data themselves. The consequences of using either WVR data or Kalman filtering to correct for atmospheric propagation delay at the Onsala VLBI site are investigated by studying the repeatability of estimated baseline lengths from Onsala to several other sites. The repeatability obtained for baseline length estimates shows that the methods of water vapor radiometry and Kalman filtering offer comparable accuracies when applied to VLBI observations obtained in the climate of the Swedish west coast. For the most frequently measured baseline in this study, the use of WVR data yielded a 13 percent smaller weighted-root-mean-square (WRMS) scatter of the baseline length estimates compared to the use of a Kalman filter. It is also clear that the 'best' minimum elevationi angle for VLBI observations depends on the accuracy of the determinations of the total propagation delay to be used, since the error in this delay increases with increasing air mass.

  18. Effect of temperature on passive remote sensing of chemicals by differential absorption radiometry

    NASA Astrophysics Data System (ADS)

    Holland, Stephen K.; Krauss, Roland H.; Laufer, Gabriel

    2005-10-01

    Differential absorption radiometry (DAR), using uncooled detectors, is a simple, low-cost method for passive remote sensing of hazardous chemicals for domestic security applications. However, radiometric temperature differences (ΔTeffective) between a target gas species and its background affect detection sensitivity. Two DARs with sensitivities to methanol, diisopropyl methylphosphonate (DIMP), and dimethyl methylphosphonate (DMMP), all spectral or physical simulants of hazardous chemicals, were developed and used to experimentally determine the effect of |ΔTeffective| on detection sensitivity. An analytical model was also developed and compared with the experimental results. With a signal-to-noise ratio (SNR)>5, a |ΔTeffective|≥2 K is sufficient for rapid (≤1 s) detection of methanol at <0.03 atm cm and DMMP and DIMP at <0.001 atm cm. These measured sensitivities suggest that rapid detection of hazardous chemical vapor clouds below lethal dose concentrations can be achieved using room-temperature pyroelectric detectors. Measurements were within 3% of the analytical predictions.

  19. Geodesy by radio interferometry - Water vapor radiometry for estimation of the wet delay

    NASA Technical Reports Server (NTRS)

    Elgered, G.; Davis, J. L.; Herring, T. A.; Shapiro, I. I.

    1991-01-01

    An important source of error in VLBI estimates of baseline length is unmodeled variations of the refractivity of the neutral atmosphere along the propagation path of the radio signals. This paper presents and discusses the method of using data from a water vapor radiomete (WVR) to correct for the propagation delay caused by atmospheric water vapor, the major cause of these variations. Data from different WVRs are compared with estimated propagation delays obtained by Kalman filtering of the VLBI data themselves. The consequences of using either WVR data or Kalman filtering to correct for atmospheric propagation delay at the Onsala VLBI site are investigated by studying the repeatability of estimated baseline lengths from Onsala to several other sites. The repeatability obtained for baseline length estimates shows that the methods of water vapor radiometry and Kalman filtering offer comparable accuracies when applied to VLBI observations obtained in the climate of the Swedish west coast. For the most frequently measured baseline in this study, the use of WVR data yielded a 13 percent smaller weighted-root-mean-square (WRMS) scatter of the baseline length estimates compared to the use of a Kalman filter. It is also clear that the 'best' minimum elevationi angle for VLBI observations depends on the accuracy of the determinations of the total propagation delay to be used, since the error in this delay increases with increasing air mass.

  20. The Effect of Underwater Imagery Radiometry on 3d Reconstruction and Orthoimagery

    NASA Astrophysics Data System (ADS)

    Agrafiotis, P.; Drakonakis, G. I.; Georgopoulos, A.; Skarlatos, D.

    2017-02-01

    The work presented in this paper investigates the effect of the radiometry of the underwater imagery on automating the 3D reconstruction and the produced orthoimagery. Main aim is to investigate whether pre-processing of the underwater imagery improves the 3D reconstruction using automated SfM - MVS software or not. Since the processing of images either separately or in batch is a time-consuming procedure, it is critical to determine the necessity of implementing colour correction and enhancement before the SfM - MVS procedure or directly to the final orthoimage when the orthoimagery is the deliverable. Two different test sites were used to capture imagery ensuring different environmental conditions, depth and complexity. Three different image correction methods are applied: A very simple automated method using Adobe Photoshop, a developed colour correction algorithm using the CLAHE (Zuiderveld, 1994) method and an implementation of the algorithm described in Bianco et al., (2015). The produced point clouds using the initial and the corrected imagery are then being compared and evaluated.

  1. Assessment of Satellite Ocean Colour Radiometry and Derived Geophysical Products. Chapter 6.1

    NASA Technical Reports Server (NTRS)

    Melin, Frederic; Franz, Bryan A.

    2014-01-01

    Standardization of methods to assess and assign quality metrics to satellite ocean color radiometry and derived geophysical products has become paramount with the inclusion of the marine reflectance and chlorophyll-a concentration (Chla) as essential climate variables (ECV; [1]) and the recognition that optical remote sensing of the oceans can only contribute to climate research if and when a continuous succession of satellite missions can be shown to collectively provide a consistent, long-term record with known uncertainties. In 20 years, the community has made significant advancements toward that objective, but providing a complete uncertainty budget for all products and for all conditions remains a daunting task. In the retrieval of marine water-leaving radiance from observed top-of-atmosphere radiance, the sources of uncertainties include those associated with propagation of sensor noise and radiometric calibration and characterization errors, as well as a multitude of uncertainties associated with the modeling and removal of effects from the atmosphere and sea surface. This chapter describes some common approaches used to assess quality and consistency of ocean color satellite products and reviews the current status of uncertainty quantification in the field. Its focus is on the primary ocean color product, the spectrum of marine reflectance Rrs, but uncertainties in some derived products such as the Chla or inherent optical properties (IOPs) will also be considered.

  2. Kinetic Atom.

    ERIC Educational Resources Information Center

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  3. Kinetic Atom.

    ERIC Educational Resources Information Center

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  4. EDITORIAL: The 10th International Conference on New Developments and Applications in Optical Radiometry (NEWRAD 2008) The 10th International Conference on New Developments and Applications in Optical Radiometry (NEWRAD 2008)

    NASA Astrophysics Data System (ADS)

    Ikonen, Erkki

    2009-08-01

    This special issue of Metrologia contains selected papers from the NEWRAD 2008 Conference, held in Daejeon, Korea, on 12-16 October 2008. NEWRAD 2008 continues a series of conferences on radiometry entitled 'New Developments and Applications in Optical Radiometry', which have taken place as follows: Cambridge, MA, USA (1985) Teddington, UK (1988) Davos, Switzerland (1990) Baltimore, MD, USA (1992) Berlin, Germany (1994) Tucson, AZ, USA (1997) Madrid, Spain (1999) Gaithersburg, MD, USA (2002) Davos, Switzerland (2005) Daejeon, Korea (2008) As the first NEWRAD Conference arranged in Asia, NEWRAD 2008 opened a new era for this series of conferences. The conference was followed by a Workshop on High Temperature Fixed Points and meetings of the Working Groups of the Consultative Committee for Photometry and Radiometry (CCPR). The organizer of all these events was Dr In Won Lee of the Korea Research Institute of Standards and Science (KRISS). The NEWRAD Scientific Committee thanks him and his team for their tremendous efforts which maintained and developed the high standards of previous NEWRAD Conferences. The specific themes of NEWRAD 2008 included optical measurements related to displays, energy and terahertz applications. Furthermore, half a day of sessions was devoted to both remote sensing and to few-photon sources and detectors. A total of 140 papers were presented, including 11 invited and 30 contributed talks. The conference proceedings containing two-page extended abstracts were distributed to the participants as a paper volume and on a USB memory stick. The authors of selected contributions were invited to submit a full paper for this special issue. The submitted papers were handled by the normal reviewing procedures of Metrologia. On behalf of the Scientific Committee, I thank the reviewers and editorial staff of Metrologia for careful processing of the manuscripts. It is evident that this special issue, like its predecessors, will serve as an important

  5. FOREWORD: The 11th International Conference on New Developments and Applications in Optical Radiometry (NEWRAD 2011) The 11th International Conference on New Developments and Applications in Optical Radiometry (NEWRAD 2011)

    NASA Astrophysics Data System (ADS)

    Ikonen, Erkki

    2012-04-01

    The NEWRAD Conferences bring together people from the National Metrology Institutes and the principal user communities of advanced radiometry, including Earth observation and climate communities. The eleventh NEWRAD Conference was held in Hawaii, USA, between 18 and 23 September 2011. The Conference was organized by the Moss Landing Marine Laboratories, Maui, at the Grand Wailea resort. The organization was a joint Pacific effort, where handling of the submitted abstracts and website administration were taken care of by KRISS (Korea Research Institute of Standards and Science) and NIST (National Institute of Standards and Technology), respectively. As satellite activities, the working groups of CCPR (Consultative Committee for Photometry and Radiometry) and the MOBY project arranged meetings at the Grand Wailea before and after the Conference. The Conference was attended by more than a hundred registered participants from five continents, which matches the number of foreign participants of NEWRAD 2008 at KRISS. A total of 153 papers were presented at NEWRAD 2011, of which 10 were invited talks and 100 posters. The poster sessions during the extended lunch breaks created a stimulating atmosphere for lively discussions and exchange of ideas. A technical visit was arranged to the astronomical observatory at the summit of Haleakala volcano, where some of the world's most advanced telescope systems are operated. The relaxed Hawaiian life, nearby ocean and excellent weather conditions gave an unprecedented flavour to this NEWRAD Conference. The abstract classification system was renewed for NEWRAD 2011, consisting of the following categories: EAO: Earth observation SSR: Solar/stellar radiometry SBR: Source-based radiometry OPM: Optical properties of materials/components DBR: Detector-based radiometry SFR: Single/few-photon radiometry. The new system worked well for refereeing and program purposes. Conference proceedings containing two-page extended abstracts were

  6. Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Moe, Owen; Cornelius, Richard

    1988-01-01

    Conveys an appreciation of enzyme kinetic analysis by using a practical and intuitive approach. Discusses enzyme assays, kinetic models and rate laws, the kinetic constants (V, velocity, and Km, Michaels constant), evaluation of V and Km from experimental data, and enzyme inhibition. (CW)

  7. Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Moe, Owen; Cornelius, Richard

    1988-01-01

    Conveys an appreciation of enzyme kinetic analysis by using a practical and intuitive approach. Discusses enzyme assays, kinetic models and rate laws, the kinetic constants (V, velocity, and Km, Michaels constant), evaluation of V and Km from experimental data, and enzyme inhibition. (CW)

  8. Characterization of a digital microwave radiometry system for noninvasive thermometry using a temperature-controlled homogeneous test load.

    PubMed

    Arunachalam, K; Stauffer, P R; Maccarini, P F; Jacobsen, S; Sterzer, F

    2008-07-21

    Microwave radiometry has been proposed as a viable noninvasive thermometry approach for monitoring subsurface tissue temperatures and potentially controlling power levels of multielement heat applicators during clinical hyperthermia treatments. With the evolution of technology, several analog microwave radiometry devices have been developed for biomedical applications. In this paper, we describe a digital microwave radiometer with built-in electronics for signal processing and automatic self-calibration. The performance of the radiometer with an Archimedean spiral receive antenna is evaluated over a bandwidth of 3.7-4.2 GHz in homogeneous and layered water test loads. Controlled laboratory experiments over the range of 30-50 degrees C characterize measurement accuracy, stability, repeatability and penetration depth sensitivity. The ability to sense load temperature through an intervening water coupling bolus of 6 mm thickness is also investigated. To assess the clinical utility and sensitivity to electromagnetic interference (EMI), experiments are conducted inside standard clinical hyperthermia treatment rooms with no EM shielding. The digital radiometer provided repeatable measurements with 0.075 degrees C resolution and standard deviation of 0.217 degrees C for homogeneous and layered tissue loads at temperatures between 32-45 degrees C. Within the 3.7-4.2 GHz band, EM noise rejection was good other than some interference from overhead fluorescent lights in the same room as the radiometer. The system response obtained for ideal water loads suggests that this digital radiometer should be useful for estimating subcutaneous tissue temperatures under a 6 mm waterbolus used during clinical hyperthermia treatments. The accuracy and stability data obtained in water test loads of several configurations support our expectation that single band radiometry should be sufficient for sub-surface temperature monitoring and power control of large multielement array superficial

  9. Molecular phylogenetic inference from saber-toothed cat fossils of Rancho La Brea.

    PubMed Central

    Janczewski, D N; Yuhki, N; Gilbert, D A; Jefferson, G T; O'Brien, S J

    1992-01-01

    A method for the successful extraction of sequestered cellular DNA from 14,000-year-old fossil bones was developed and applied to asphalt-preserved specimens of the extinct saber-toothed cat, Smilodon fatalis. Two distinct gene segments, the mitochondrial gene for 12S rRNA and nuclear FLA-I (the feline class I major histocompatibility complex gene), from three different individual fossil specimens were cloned and sequenced after PCR amplification. Comparison of fossil-derived DNA sequences to homologous regions in 15 living carnivorous species, including 9 species of Felidae and 6 nonfelids, affirmed the phylogenetic placement of Smilodon within the modern radiation of Felidae distinct from the Miocene paleofelid (Nimravidae) saber-toothed "cat" species. These results raise the prospect of obtaining genetically informative DNA from preserved bones of extinct fossil species, particularly among the 2 million specimens excavated from the asphaltic sediments at Rancho La Brea in metropolitan Los Angeles. PMID:1409696

  10. Flow characteristics in the airways of a COPD patient with a saber-sheath trachea

    NASA Astrophysics Data System (ADS)

    Jin, Dohyun; Choi, Haecheon; Lee, Changhyun; Choi, Jiwoong; Kim, Kwanggi

    2016-11-01

    The chronic obstructive pulmonary disease (COPD) is a lung disease characterized by the irreversible airflow limitation caused by the damaged small airways and air sacs. Although COPD is not a disease of the trachea, many patients with COPD have saber-sheath tracheas. The effects of this morphological change in the trachea geometry on airflow are investigated in the present study. An unstructured finite volume method is used for the simulations during tidal breathing in normal and COPD airways, respectively. During inspiration, local large pressure drop is observed in the saber-sheath region of the COPD patient. During expiration, vortical structures are observed at the right main bronchus of the COPD airway, while the flow in the normal airway remains nearly laminar. High wall shear stress exists at convex regions of both airways during inspiration and expiration. However, due to the morphological changes in the COPD airway, relatively higher wall shear stress is observed in the patient airways.

  11. CoSSIR: A New Instrument for Exploring the Utility of Submillimeter-wave Radiometry for Earth Observation

    NASA Technical Reports Server (NTRS)

    Racette, P. E.; Wang, J. R.; Evans, K. F.; Momosmith, B.; Zhang, Z.

    2004-01-01

    The Conical Scanning Submillimeter-wave Imaging Radiometer (CoSSIR) has been developed to study the application of submillimeter-wave radiometry for remote sensing of cirrus clouds and humidity sounding. Measurements of the global distribution of ice cloud mass and particle size are important for understanding the Earth s energy budget and for evaluating global climate models. The spatial variability and the wide variety of cloud particle shapes and sizes make ice clouds particularly difficult to measure. Ice clouds are essentially undetectable at microwave frequencies due to the low dielectric of ice and small size of the particles relative to wavelength. However, submillimeter wavelengths demonstrate significant response to the presence of ice clouds thus this frequency regime is applicable to measuring ice clouds. Another potentially viable application for submillimeter-wave radiometry is humidity and temperature sounding. The principle of sounding at submillimeter wavelengths is similar to that at microwavelengths. Submillimeter-wave radiometry has the advantage of achieving finer spatial resolution using a smaller antenna aperture which is an important consideration for spaceborne observatories. Submillimeter-wave radiometry also offers the potential of sounding over land and as a surrogate measurement for precipitation. CoSSIR is a new instrument to explore these applications. The CoSSIR is designed to fly aboard the ER-2 aircraft and its modest size (approximately 100 kg) permits it to be configured for other aircraft. A dual-axes gimbals mechanism provides conical, across-track, and along-track scanning capability. In its present configuration CoSSIR has fifteen channels between 183 GHz and 640 GHz. Three channels are centered about the 183 GHz water vapor absorption line, four channels are centered about the 380 GHz water vapor absorption line, and three dual-polarized channels are centered about the 487 GHz oxygen absorption line. Two channels are located

  12. Optothermal transient emission radiometry for studying the changes in epidermal hydration induced during ripening of tomato fruit mutants

    NASA Astrophysics Data System (ADS)

    Guo, X.; Bicanic, D.; Imhof, R.; Xiao, P.; Harbinson, J.

    2004-10-01

    Optothermal transient emission radiometry (OTTER) was used to determine the mean surface hydration and the hydration profile of three mutants (beefsteak, slicing and salad) of harvested tomatoes (Lycopersicon esculentum) that were kept under ambient conditions for as long as 51 days. Maximal sensitivity of OTTER to water in the samples was achieved by using 2.94 μm and 13.1 μm as excitation and emission wavelengths, respectively. The surface hydration increases rapidly and reaches a constant level during the remaining period. The hydrolysis of pectic substances that occur in tomatoes while ripening might be a possible cause for the observed change in hydration.

  13. Object-Oriented Analysis, Design, and Implementation of the Saber Wargame

    DTIC Science & Technology

    1992-12-01

    this functionality using the machinery of artficial intelligence and expert systems. 3. And the third is that objects provide a natural basis for...3.2.7 Intelligence ................................. 31 3.2.8 Weather ................................... 31 3.2.9 Clock...and intelligence which add to the realism of the Saber war game. The Sabcr war game has three main components, the preprocessor, which is respon

  14. Intra-seasonal Oscillations Inferred from SABER (TIMED) and MLS (UARS) Temperature Measurements

    NASA Technical Reports Server (NTRS)

    Huang, F. T.; Mayr, H. G.; Russell, J.; Mlynczak, M.; Reber, C. A.; Mengel, J. G.

    2006-01-01

    In the zonal mean meridional winds of the upper mesosphere, intra-seasonal oscillations with periods between 1 and 4 months have been inferred from UARS measurements and independently predicted with the Numerical Spectral Model WSM). The wind oscillations tend to be confined to low latitudes and appear to be driven, at least in part, by small-scale gravity waves propagating in the meridional direction. Winds across the equator should generate, due to dynamical heating and cooling, temperature oscillations with opposite phase in the two hemispheres. Investigating this phenomenon, we have analyzed SABER temperatures from TIMED in the altitude range between 55 and 95 km to delineate with an empirical model, the year-long variability of the migrating tides and zonal mean components. The inferred seasonal variations of the diurnal tide, characterized by amplitude maxima near equinox, are in substantial agreement with UARS observations and results from the NSM. For the zonal mean, the dominant seasonal variations in the SABER temperatures, with annual (12 months) and semiannual (6 months) periodicities, agree well with those derived from UARS measurements. The intra-seasonal variations with periods between 2 and 4 months have amplitudes close to 2 K, almost half as large as those for the dominant seasonal variations. Their amplitudes are in qualitative agreement with the corresponding values inferred from UARS during different years. The SABER and UARS temperature variations reveal pronounced hemispherical asymmetries, consistent with meridional wind oscillations across the equator. The phase of the semi-annual temperature oscillations from the NSM agrees with the observations from UARS and SABER. But the amplitudes are systematically smaller, which may indicate that planetary waves are more important than is allowed for in the model. For the shorter-period intra-seasonal variations, which can be generated by gravity wave drag, the model results are generally in better

  15. Aerosol optical depth derived from solar radiometry observations at northern mid-latitude sites

    SciTech Connect

    Laulainen, N.S.; Larson, N.R.; Michalsky, J.J.; Harrison, L.C.

    1994-01-01

    Routine, automated solar radiometry observations began with the development of the Mobile Automated Scanning Photometer (MASP) and its installation at the Rattlesnake Mountain Observatory (RMO). We have introduced a microprocessor controlled rotating shadowband radiometer (RSR), both the single detector and the multi-filter/detector (MFRSR) versions to replace the MASP. The operational mode of the RSRs is substantially different than the MASP or other traditional sun-tracking radiometers, because, by virtue of the automated rotating shadowband, the total and diffuse irradiance on a horizontal plane are measured and the direct-normal component deduced through computation from the total and diffuse components by the self-contained microprocessor. Because the three irradiance components are measured using the same detector for a given wavelength, the calibration coefficients are identical for each component, thus reducing errors when comparing them. The MFRSR is the primary radiometric instrument in the nine-station Quantitative Links Network (QLN) established in the eastern United States in late 1991. Data from this network are being used to investigate how cloud- and aerosol-induced radiative effects vary in time and with cloud structure and type over a mid-latitude continental region. This work supports the DOE Quantitative Links Program to quantify linkages between changes in atmospheric composition and climate forcing. In this paper we describe the setup of the QLN and present aerosol optical depth results from the on-going measurements at PNL/RMO, as well as preliminary results from the QLN. From the time-series of data at each site, we compare seasonal variability and geographical differences, as well as the effect of the perturbation to the stratosphere by Mt. Pinatubo. Analysis of the wavelength dependence of optical depth also provides information on the evolution and changes in the size distribution of the aerosols.

  16. Passive monitoring using a combination of focused and phased array radiometry: a simulation study.

    PubMed

    Farantatos, Panagiotis; Karanasiou, Irene S; Uzunoglu, Nikolaos

    2011-01-01

    Aim of this simulation study is to use the focusing properties of a conductive ellipsoidal reflector in conjunction with directive phased microwave antenna configurations in order to achieve brain passive monitoring with microwave radiometry. One of the main modules of the proposed setup which ensures the necessary beamforming and focusing on the body and brain areas of interest is a symmetrical axis ellipsoidal conductive wall cavity. The proposed system operates in an entirely non-invasive contactless manner providing temperature and/or conductivity variations monitoring and is designed to also provide hyperthermia treatment. In the present paper, the effect of the use of patch antennas as receiving antennas on the system's focusing properties and specifically the use of phased array setups to achieve scanning of the areas under measurement is investigated. Extensive simulations to compute the electric field distributions inside the whole ellipsoidal reflector and inside two types of human head models were carried out using single and two element microstrip patch antennas. The results show that clear focusing (creation of "hot spots") inside the head models is achieved at 1.53GHz. In the case of the two element antennas, the "hot spot" performs a linear scan around the brain area of interest while the phase difference of the two microstrip patch antennas significantly affects the way the scanning inside the head model is achieved. In the near future, phased array antennas with multiband and more elements will be used in order to enhance the system scanning properties toward the acquisition of tomography images without the need of subject movement.

  17. Baseline Surface Radiation Network (BSRN/WCRP): New Precision Radiometry for Climate Research.

    NASA Astrophysics Data System (ADS)

    Ohmura, Atsumu; Gilgen, Hans; Hegner, Herman; Müller, Guido; Wild, Martin; Dutton, Ellsworth G.; Forgan, Bruce; Fröhlich, Claus; Philipona, Rolf; Heimo, Alain; König-Langlo, Gert; McArthur, Bruce; Pinker, Rachel; Whitlock, Charlie H.; Dehne, Klaus

    1998-10-01

    To support climate research, the World Climate Research Programme (WCRP) initiated a new radiometric network, the Baseline Surface Radiation Network (BSRN). The network aims at providing validation material for satellite radiometry and climate models. It further aims at detecting long-term variations in irradiances at the earth's surface, which are believed to play an important role in climate change. The network and its instrumentation are designed 1) to cover major climate zones, 2) to provide the accuracy required to meet the objectives, and 3) to ensure homogenized standards for a long period in the future. The limits of the accuracy are defined to reach these goals. The suitable instruments and instrumentations have been determined and the methods for observations and data management have been agreed on at all stations. Measurements of irradiances are at 1 Hz, and the 1-min statistics (mean, standard deviation, and extreme values) with quality flags are stored at a centralized data archive at the WCRP's World Radiation Monitoring Center (WRMC) in Zurich, Switzerland. The data are quality controlled both at stations and at the WRMC. The original 1-min irradiance statistics will be stored at the WRMC for 10 years, while hourly mean values will be transferred to the World Radiation Data Center in St. Petersburg, Russia. The BSRN, consisting of 15 stations, covers the earth's surface from 80°N to 90°S, and will soon be joined by seven more stations. The data are available to scientific communities in various ways depending on the communication environment of the users. The present article discusses the scientific base, organizational and technical aspects of the network, and data retrieval methods; shows various application possibilities; and presents the future tasks to be accomplished.

  18. Geodesy by radio interferometry: Water vapor radiometry for estimation of the wet delay

    SciTech Connect

    Elgered, G.; Davis, J.L.; Herring, T.A.; Shapiro, I.I. )

    1991-04-10

    An important source of error in very-long-baseline interferometry (VLBI) estimates of baseline length is unmodeled variations of the refractivity of the neutral atmosphere along the propagation path of the radio signals. The authors present and discuss the method of using data from a water vapor readiometer (WVR) to correct for the propagation delay caused by atmospheric water vapor, the major cause of these variations. Data from different WVRs are compared with estimated propagation delays obtained by Kalman filtering of the VLBI data themselves. The consequences of using either WVR data of Kalman filtering to correct for atmospheric propagation delay at the Onsala VLBI site are investigated by studying the repeatability of estimated baseline lengths from Onsala to several other sites. The lengths of the baselines range from 919 to 7,941 km. The repeatability obtained for baseline length estimates shows that the methods of water vapor radiometry and Kalman filtering offer comparable accuracies when applied to VLBI observations obtained in the climate of the Swedish west coast. The use of WVR data yielded a 13% smaller weighted-root-mean-square (WRMS) scatter of the baseline length estimates compared to the use of a Kalman filter. It is also clear that the best minimum elevation angle for VLBI observations depends on the accuracy of the determinations of the total propagation delay to be used, since the error in this delay increases with increasing air mass. For use of WVR data along with accurate determinations of total surface pressure, the best minimum is about 20{degrees}; for use of a model for the wet delay based on the humidity and temperature at the ground, the best minimum is about 35{degrees}.

  19. Zonal-Mean Temperature Variations Inferred from SABER Measurements on TIMED Compared with UARS Observations

    NASA Technical Reports Server (NTRS)

    Huang, Frank T.; Mayr, Hans; Russell, James; Mlynczak, Marty; Reber, Carl A.

    2005-01-01

    In the Numerical Spectral Model (NSM, Mayr et al., 2003), small-scale gravity waves propagating in the north/south direction can generate zonal mean (m = 0) meridional wind oscillations with periods between 2 and 4 months. These oscillations tend to be confined to low latitudes and have been interpreted to be the meridional counterpart of the wave-driven Quasi Biennial Oscillation in the zonal circulation. Wave driven meridional winds across the equator should generate, due to dynamical heating and cooling, temperature oscillations with opposite phase in the two hemispheres. We have analyzed SABER temperature measurements in the altitude range between 55 and 95 km to investigate the existence such variations. Because there are also strong tidal signatures (up to approximately 20 K) in the data, our algorithm estimates both mean values and tides together from the data. Based on SABER temperature data, the intra-annual variations with periods between 2 and 4 months can have amplitudes up to 5 K or more, depending on the altitude. Their amplitudes are in qualitative agreement with those inferred Erom UARS data (from different years). The SABER temperature variations also reveal pronounced hemispherical asymmetries, which are qualitatively consistent with wave driven meridional wind oscillations across the equator. Oscillations with similar periods have been seen in the meridional winds based on UARS data (Huang and Reber, 2003).

  20. Zonal-Mean Temperature Variations Inferred from SABER Measurements on TIMED Compared with UARS Observations

    NASA Technical Reports Server (NTRS)

    Huang, Frank T.; Mayr, Hans; Russell, James; Mlynczak, Marty; Reber, Carl A.

    2005-01-01

    In the Numerical Spectral Model (NSM, Mayr et al., 2003), small-scale gravity waves propagating in the north/south direction can generate zonal mean (m = 0) meridional wind oscillations with periods between 2 and 4 months. These oscillations tend to be confined to low latitudes and have been interpreted to be the meridional counterpart of the wave-driven Quasi Biennial Oscillation in the zonal circulation. Wave driven meridional winds across the equator should generate, due to dynamical heating and cooling, temperature oscillations with opposite phase in the two hemispheres. We have analyzed SABER temperature measurements in the altitude range between 55 and 95 km to investigate the existence such variations. Because there are also strong tidal signatures (up to approximately 20 K) in the data, our algorithm estimates both mean values and tides together from the data. Based on SABER temperature data, the intra-annual variations with periods between 2 and 4 months can have amplitudes up to 5 K or more, depending on the altitude. Their amplitudes are in qualitative agreement with those inferred Erom UARS data (from different years). The SABER temperature variations also reveal pronounced hemispherical asymmetries, which are qualitatively consistent with wave driven meridional wind oscillations across the equator. Oscillations with similar periods have been seen in the meridional winds based on UARS data (Huang and Reber, 2003).

  1. Identification of the photoluminescence response in the frequency domain modulated infrared radiometry signal of ZnTe:Cr bulk crystal

    NASA Astrophysics Data System (ADS)

    Pawlak, M.; Strzałkowski, K.

    2016-09-01

    In this work we investigated the photoluminescence response in the frequency domain modulated infrared radiometry signal observed of ZnTe:Cr bulk crystal. In mid-infrared range, three characteristic phenomena are observed in ZnTe:Cr crystal: absorption and emission of IR photons (2-3 μm) and the free carrier absorption. This implies that the modulated infrared radiometry signal yields information about the effective infrared absorption coefficient (photothermal response) as well about the recombination lifetime of carriers related with the infrared photoluminescence emission. In this paper, the frequency equivalence of the two-term independent exponential photoluminescence decay model in order to explain the measured frequency characteristics is proposed. The measured recombination lifetimes (2.3 μs for two exponential decay model and 1.5 μs for one exponential decay model) are in good agreement with the values given by other authors (about 2.5-3.0 μs). Moreover, we found that the photothermal response is uncorrelated with the photoluminescence one, in contrast, to the photocarrier response.

  2. A study on the use of passive microwave radiometry for the detection of buried objects and their associated hydrological changes

    NASA Astrophysics Data System (ADS)

    van de Ven, Robbert; de Jeu, Richard; Haarbrink, Roland

    2014-10-01

    The detection of buried objects with remote sensing techniques mainly relies on thermal infrared, ground penetrating radar, and metal detectors. However, nowadays people also start to use low frequency passive microwave radiometry for the same purpose. The detection performance of passive microwave radiometry is influenced by the depth and size of the object, environmental factors, and soil properties. Soil moisture is a key variable here, due to its strong influence on the observed dielectric constant. Through digging activities will the hydrological conditions of the soil change significantly that can be detected by remotely sensing systems. A study was designed to examine the influence of the hydrological changes caused by the direct placement of an object in the ground. Simulations in a soil moisture model and field observations revealed the development of a wetter part above and a drier part underneath an object. The observations were converted to brightness temperatures with a coherent model in combination with a dielectric mixing model. Development of a drier area underneath an object generally increases the brightness temperature after a precipitation event. As a results are brightness temperature anomalies of low dielectric constant objects raised during the first 36 hours after a rain event. Ground observations of soil moisture and porosity revealed an increase in porosity and loss in soil moisture for the part that was excavated. Knowledge of past weather conditions could therefore improve buried object detection by passive microwave sensors.

  3. Foreword to the Special Issue on the 11th Specialist Meeting on Microwave Radiometry and Remote Sensing Applications (MicroRad 2010)

    NASA Technical Reports Server (NTRS)

    Le Vine, David M; Jackson, Thomas J.; Kim, Edward J.; Lang, Roger H.

    2011-01-01

    The Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment (MicroRad 2010) was held in Washington, DC from March 1 to 4, 2010. The objective of MicroRad 2010 was to provide an open forum to report and discuss recent advances in the field of microwave radiometry, particularly with application to remote sensing of the environment. The meeting was highly successful, with more than 200 registrations representing 48 countries. There were 80 oral presentations and more than 100 posters. MicroRad has become a venue for the microwave radiometry community to present new research results, instrument designs, and applications to an audience that is conversant in these issues. The meeting was divided into 16 sessions (listed in order of presentation): 1) SMOS Mission; 2) Future Passive Microwave Remote Sensing Missions; 3) Theory and Physical Principles of Electromagnetic Models; 4) Field Experiment Results; 5) Soil Moisture and Vegetation; 6) Snow and Cryosphere; 7) Passive/Active Microwave Remote Sensing Synergy; 8) Oceans; 9) Atmospheric Sounding and Assimilation; 10) Clouds and Precipitation; 11) Instruments and Advanced Techniques I; 12) Instruments and Advanced Techniques II; 13) Cross Calibration of Satellite Radiometers; 14) Calibration Theory and Methodology; 15) New Technologies for Microwave Radiometry; 16) Radio Frequency Interference.

  4. Foreword to the Special Issue on the 11th Specialist Meeting on Microwave Radiometry and Remote Sensing Applications (MicroRad 2010)

    NASA Technical Reports Server (NTRS)

    Le Vine, David M; Jackson, Thomas J.; Kim, Edward J.; Lang, Roger H.

    2011-01-01

    The Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment (MicroRad 2010) was held in Washington, DC from March 1 to 4, 2010. The objective of MicroRad 2010 was to provide an open forum to report and discuss recent advances in the field of microwave radiometry, particularly with application to remote sensing of the environment. The meeting was highly successful, with more than 200 registrations representing 48 countries. There were 80 oral presentations and more than 100 posters. MicroRad has become a venue for the microwave radiometry community to present new research results, instrument designs, and applications to an audience that is conversant in these issues. The meeting was divided into 16 sessions (listed in order of presentation): 1) SMOS Mission; 2) Future Passive Microwave Remote Sensing Missions; 3) Theory and Physical Principles of Electromagnetic Models; 4) Field Experiment Results; 5) Soil Moisture and Vegetation; 6) Snow and Cryosphere; 7) Passive/Active Microwave Remote Sensing Synergy; 8) Oceans; 9) Atmospheric Sounding and Assimilation; 10) Clouds and Precipitation; 11) Instruments and Advanced Techniques I; 12) Instruments and Advanced Techniques II; 13) Cross Calibration of Satellite Radiometers; 14) Calibration Theory and Methodology; 15) New Technologies for Microwave Radiometry; 16) Radio Frequency Interference.

  5. Detection of greenbug infestation on wheat using ground-based radiometry

    NASA Astrophysics Data System (ADS)

    Yang, Zhiming

    Scope of methods of study. The purpose of this greenhouse study was to characterize stress in wheat caused by greenbugs using ground-based radiometry. Experiments were conducted to (a) identify spectral bands and vegetation indices sensitive to greenbug infestation; (b) differentiate stress caused due to greenbugs from water stress; (c) examine the impacts of plant growth stage on detection of greenbug infestation; and (d) compare infestations due to greenbug and Russian wheat aphid. Wheat (variety-TAM 107) was planted (seed spacing 1 in. x 3 in.) in plastic flats with dimension 24 in. x 16 in. x 8.75 in. Fifteen days after sowing, wheat seedlings were infested with greenbugs (biotype-E). Nadir measurement of canopy reflectance started the day after infestation and lasted until most infested plants were dead. Using a 16-band Cropscan radiometer, spectral reflectance data were collected daily (between 13:00--14:00 hours) and 128 vegetation indices were derived in addition to greenbug counts per tiller. Using SAS PROC MIXED, sensitivity of band and vegetation indices was identified based on Threshold Day. Subsequent to Threshold Day there was a consistent significant spectral difference between control and infested plants. Sensitivity of band and vegetation indices was further examined using correlation and relative sensitivity analyses. Findings and conclusions. Results show that it is possible to detect greenbug-induced stress on wheat using hand-held radiometers, such as Cropscan. Band 694 nm and the ratio-based vegetation index (RVI) derived from the band 694 nm and 800 nm were identified as most sensitive to greenbug infestation. Landsat TM bands and their derived vegetation indices also show potential for detecting wheat stress caused by greenbug infestation. Also, RVIs particularly derived using spectral band 694 nm and 800 nm were found useful in differentiating greenbug infestation from water stress. Furthermore, vegetation indices such as Normalized total

  6. Stable microwave radiometry system for long term monitoring of deep tissue temperature

    NASA Astrophysics Data System (ADS)

    Stauffer, Paul R.; Rodriques, Dario B.; Salahi, Sara; Topsakal, Erdem; Oliveira, Tiago R.; Prakash, Aniruddh; D'Isidoro, Fabio; Reudink, Douglas; Snow, Brent W.; Maccarini, Paolo F.

    2013-02-01

    Background: There are numerous clinical applications for non-invasive monitoring of deep tissue temperature. We present the design and experimental performance of a miniature radiometric thermometry system for measuring volume average temperature of tissue regions located up to 5cm deep in the body. Methods: We constructed a miniature sensor consisting of EMI-shielded log spiral microstrip antenna with high gain onaxis and integrated high-sensitivity 1.35GHz total power radiometer with 500 MHz bandwidth. We tested performance of the radiometry system in both simulated and experimental multilayer phantom models of several intended clinical measurement sites: i) brown adipose tissue (BAT) depots within 2cm of the skin surface, ii) 3-5cm deep kidney, and iii) human brain underlying intact scalp and skull. The physical models included layers of circulating tissue-mimicking liquids controlled at different temperatures to characterize our ability to quantify small changes in target temperature at depth under normothermic surface tissues. Results: We report SAR patterns that characterize the sense region of a 2.6cm diameter receive antenna, and radiometric power measurements as a function of deep tissue temperature that quantify radiometer sensitivity. The data demonstrate: i) our ability to accurately track temperature rise in realistic tissue targets such as urine refluxed from prewarmed bladder into kidney, and 10°C drop in brain temperature underlying normothermic scalp and skull, and ii) long term accuracy and stability of +0.4°C over 4.5 hours as needed for monitoring core body temperature over extended surgery or monitoring effects of brown fat metabolism over an extended sleep/wake cycle. Conclusions: A non-invasive sensor consisting of 2.6cm diameter receive antenna and integral 1.35GHz total power radiometer has demonstrated sufficient sensitivity to track clinically significant changes in temperature of deep tissue targets underlying normothermic surface

  7. X-Band Microwave Radiometry as a Tool for Understanding the Deep Atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Steffes, P. G.; Devaraj, K.; Butler, B. J.

    2013-12-01

    Understanding the composition, structure, and spatial variability of the deep Venus atmosphere, including the boundary layer, is a key future direction identified in the Decadal Review. While only Mariner 2 carried a microwave radiometer for the expressed purpose of evaluating the Venus atmosphere, subsequent missions to Venus and other planets have used radar receivers in a "passive mode" to map the microwave emission from both surfaces and atmospheres. Additionally, successful mapping of microwave emissions from the atmospheres of Venus and the outer planets using earth-based antenna arrays have given unique insights into the composition and variability of such atmospheres. In the past two decades, multiple observations of Venus have been made at X band (3.6 cm) using the Jansky Very Large Array (VLA), and maps have been created of the 3.6 cm emission from Venus. Since the emission morphology is related both to surface features and to the deep atmospheric absorption from CO2 and SO2 (see, e.g., Butler et al., Icarus 154, 2001), emission measurements can be used to give unique information regarding the deep atmosphere, once surface effects are removed. Since surface emissivities measured at the 12.6 cm wavelength by the Magellan mission can be extrapolated to 3.6 cm (see, e.g., Tryka and Muhleman, JGR(Planets) 197, 1992), the residual effects due to deep atmospheric variability can potentially be detected, as they were for higher altitudes at shorter wavelengths (1.3 cm and 2.0 cm, Jenkins et.al., Icarus 158, 2002). As results from this study show, the limited resolution and sensitivity of earth-based measurements make detection of moderate atmospheric variability somewhat difficult. However, the higher sensitivity and resolution provided by an orbiting X-Band radiometer can provide important insights into the variability and structure of the Venus boundary layer. As shown in the figure, the vertical resolution of X-Band radiometry compares well with IR sounding

  8. The effect of tropospheric fluctuations on the accuracy of water vapor radiometry

    NASA Technical Reports Server (NTRS)

    Wilcox, J. Z.

    1992-01-01

    Line-of-sight path delay calibration accuracies of 1 mm are needed to improve both angular and Doppler tracking capabilities. Fluctuations in the refractivity of tropospheric water vapor limit the present accuracies to about 1 nrad for the angular position and to a delay rate of 3x10(exp -13) sec/sec over a 100-sec time interval for Doppler tracking. This article describes progress in evaluating the limitations of the technique of water vapor radiometry at the 1-mm level. The two effects evaluated here are: (1) errors arising from tip-curve calibration of WVR's in the presence of tropospheric fluctuations and (2) errors due to the use of nonzero beamwidths for water vapor radiometer (WVR) horns. The error caused by tropospheric water vapor fluctuations during instrument calibration from a single tip curve is 0.26 percent in the estimated gain for a tip-curve duration of several minutes or less. This gain error causes a 3-mm bias and a 1-mm scale factor error in the estimated path delay at a 10-deg elevation per 1 g/cm(sup 2) of zenith water vapor column density present in the troposphere during the astrometric observation. The error caused by WVR beam averaging of tropospheric fluctuations is 3 mm at a 10-deg elevation per 1 g/cm(sup 2) of zenith water vapor (and is proportionally higher for higher water vapor content) for current WVR beamwidths (full width at half maximum of approximately 6 deg). This is a stochastic error (which cannot be calibrated) and which can be reduced to about half of its instantaneous value by time averaging the radio signal over several minutes. The results presented here suggest two improvements to WVR design: first, the gain of the instruments should be stabilized to 4 parts in 10(exp 4) over a calibration period lasting 5 hours, and second, the WVR antenna beamwidth should be reduced to about 0.2 deg. This will reduce the error induced by water vapor fluctuations in the estimated path delays to less than 1 mm for the elevation range

  9. Terra and Aqua MODIS Design, Radiometry, and Geometry in Support of Land Remote Sensing

    NASA Technical Reports Server (NTRS)

    Xiong, Xiaoxiong; Wolfe, Robert; Barnes, William; Guenther, Bruce; Vermote, Eric; Saleous, Nazmi; Salomonson, Vincent

    2011-01-01

    The NASA Earth Observing System (EOS) mission includes the construction and launch of two nearly identical Moderate Resolution Imaging Spectroradiometer (MODIS) instruments. The MODIS proto-flight model (PFM) is onboard the EOS Terra satellite (formerly EOS AM-1) launched on December 18, 1999 and hereafter referred to as Terra MODIS. Flight model-1 (FM1) is onboard the EOS Aqua satellite (formerly EOS PM-1) launched on May 04, 2002 and referred to as Aqua MODIS. MODIS was developed based on the science community s desire to collect multiyear continuous datasets for monitoring changes in the Earth s land, oceans and atmosphere, and the human contributions to these changes. It was designed to measure discrete spectral bands, which includes many used by a number of heritage sensors, and thus extends the heritage datasets to better understand both long- and short-term changes in the global environment (Barnes and Salomonson 1993; Salomonson et al. 2002; Barnes et al. 2002). The MODIS development, launch, and operation were managed by NASA/Goddard Space Flight Center (GSFC), Greenbelt, Maryland. The sensors were designed, built, and tested by Raytheon/ Santa Barbara Remote Sensing (SBRS), Goleta, California. Each MODIS instrument offers 36 spectral bands, which span the spectral region from the visible (0.41 m) to long-wave infrared (14.4 m). MODIS collects data at three different nadir spatial resolutions: 0.25, 0.5, and 1 km. Key design specifications, such as spectral bandwidths, typical scene radiances, required signal-to-noise ratios (SNR) or noise equivalent temperature differences (NEDT), and primary applications of each MODIS spectral band are summarized in Table 7.1. These parameters were the basis for the MODIS design. More details on the evolution of the NASA EOS and development of the MODIS instruments are provided in Chap. 1. This chapter focuses on the MODIS sensor design, radiometry, and geometry as they apply to land remote sensing. With near

  10. Measurement of Low Amounts of Precipitable Water Vapor Using Ground-Based Millimeterwave Radiometry

    NASA Technical Reports Server (NTRS)

    Racette, Paul E.; Westwater, Ed R.; Han, Yong; Gasiewski, Albin J.; Klein, Marian; Cimini, Domenico; Jones, David C.; Manning, WIll; Kim, Edward J.; Wang, James R.

    2003-01-01

    Extremely dry conditions characterized by amounts of precipitable water vapor (PWV) as as 1-2 mm commonly occur in high-latitude regions during the winter months. While such atmospheres carry only a few percent of the latent heat energy compared to tropical atmospheres, the effects of low vapor amounts on the polar radiation budget - both directly through modulation of longwave radiation and indirectly through the formation of clouds - are considerable. Accurate measurements of precipitable water vapor (PWV) during such dry conditions are needed to improve polar radiation models for use in understanding and predicting change in the climatically sensitive polar regions. To this end, the strong water vapor absorption at 183.310 GHz provides a unique means of measuring low amounts of PWV. Weighting function analysis, forward model calculations based upon a 7-year radiosonde dataset, and retrieval simulations consistently predict that radiometric measurements made using several millimeter-wavelength (MMW) channels near the 183 GHz line, together with established microwave (MW) measurements at the 22.235 GHz water vapor line and -3 1 GHz atmospheric absorption window can be used to determine within 5% uncertainty the full range of PWV expected in the Arctic. This unique collective capability stands in spite of accuracy limitations stemming from uncertainties due to the sensitivity of the vertical distribution of temperature and water vapor at MMW channels. In this study the potential of MMW radiometry using the 183 GHz line for measuring low amounts of PWV is demonstrated both theoretically and experimentally. The study uses data obtained during March 1999 as part of an experiment conducted at the Department of Energy s Cloud and Radiation Testbed (CART) near Barrow, Alaska. Several radiometers from both NOAA and NASA were deployed during the experiment to provide the first combined MMW and MW ground-based data set during dry arctic conditions. Single-channel retrievals

  11. Measurement of Low Amounts of Precipitable Water Vapor Using Ground-Based Millimeterwave Radiometry

    NASA Astrophysics Data System (ADS)

    Racette, Paul E.; Westwater, Ed R.; Han, Yong; Gasiewski, Albin J.; Klein, Marian; Cimini, Domenico; Jones, David C.; Manning, Will; Kim, Edward J.; Wang, James R.; Leuski, Vladimir; Kiedron, Peter

    2005-04-01

    Extremely dry conditions characterized by amounts of precipitable water vapor (PWV) as low as 1-2 mm commonly occur in high-latitude regions during the winter months. While such dry atmospheres carry only a few percent of the latent heat energy compared to tropical atmospheres, the effects of low vapor amounts on the polar radiation budget - both directly through modulation of longwave radiation and indirectly through the formation of clouds - are considerable. Accurate measurements of PWV during such dry conditions are needed to improve polar radiation models for use in understanding and predicting change in the climatically sensitive polar regions. To this end, the strong water-vapor absorption line at 183.310 GHz provides a unique means of measuring low amounts of PWV. Weighting function analysis, forward model calculations based upon a 7-yr radiosonde dataset, and retrieval simulations consistently predict that radiometric measurements made using several millimeter-wavelength (MMW) channels near the 183-GHz line, together with established microwave (MW) measurements near the 22.235-GHz water-vapor line and ∼31-GHz atmospheric absorption window can be used to determine within 5% uncertainty the full range of PWV expected in the Arctic. This combined capability stands in spite of accuracy limitations stemming from uncertainties due to the sensitivity of the vertical distribution of temperature and water vapor at MMW channels. In this study the potential of MMW radiometry using the 183-GHz line for measuring low amounts of PWV is demonstrated both theoretically and experimentally. The study uses data obtained during March 1999 as part of an experiment conducted at the Department of Energy's Cloud and Radiation Testbed (CART) site near Barrow, Alaska. Several radiometers from both NOAA and NASA were deployed during the experiment to provide the first combined MMW and MW ground-based dataset during dry Arctic conditions. Single-channel retrievals of PWV were

  12. Remote Sensing of Methane in the Martian Atmosphere using Infrared Laser Heterodyne Radiometry

    NASA Astrophysics Data System (ADS)

    Passmore, R. L.; Bowles, N. E.; Weidmann, D.; Smith, K.

    2011-12-01

    In the last few years, several research teams have reported the detection of methane in the atmosphere of Mars, measuring 10 ppb on average [1][2][3]. The source of the methane is still unknown, but its identification is important as its presence could imply a biological origin. However, the detection limits of current instruments lie below the requirements for an unambiguous determination of concentration mapping and distribution. We investigate the viability of detecting methane in the Martian atmosphere via a high sensitivity remote sensing technique known as passive mid-infrared laser heterodyne radiometry. Although heterodyne spectroscopy is not a new idea, recent advancements in local oscillator technology [4] offer the possibility of significant instrument miniaturisation relevant to space deployment. We present our current work on a laser heterodyne radiometer (LHR) which involves adapting an existing 10 μm laser breadboard design, which was used with much success to study stratospheric ozone [5], to operate at 7.7 μm in order to target the ν4 fundamental band of methane. The core of the LHR consists of a distributed-feedback quantum cascade laser (QCL) operating in continuous-wave mode, which acts as the local oscillator. QCLs are ideal local oscillators for this type of instrument as they emit with high spectral purity and the necessary optical power in the mid-infrared region where characteristic spectral lines of interest lie. Atmospheric modelling of the Martian atmosphere and instrument sensitivity studies enabled simulated methane spectral features to be studied in detail, which subsequently determined the focus for experimental efforts in the laboratory. Testing of the LHR was initially carried out on small gas cells containing pure methane gas, but in order to test the instrument more rigorously for atmospheric studies a larger gas cell was constructed that approximates the Martian atmosphere in the laboratory. Trace quantities of methane were

  13. Stable Microwave Radiometry System for Long Term Monitoring of Deep Tissue Temperature

    PubMed Central

    Stauffer, Paul R.; Rodriques, Dario B.; Salahi, Sara; Topsakal, Erdem; Oliveira, Tiago R.; Prakash, Aniruddh; D'Isidoro, Fabio; Reudink, Douglas; Snow, Brent W.; Maccarini, Paolo F.

    2013-01-01

    Background There are numerous clinical applications for non-invasive monitoring of deep tissue temperature. We present the design and experimental performance of a miniature radiometric thermometry system for measuring volume average temperature of tissue regions located up to 5cm deep in the body. Methods We constructed a miniature sensor consisting of EMI-shielded log spiral microstrip antenna with high gain on-axis and integrated high-sensitivity 1.35GHz total power radiometer with 500 MHz bandwidth. We tested performance of the radiometry system in both simulated and experimental multilayer phantom models of several intended clinical measurement sites: i) brown adipose tissue (BAT) depots within 2cm of the skin surface, ii) 3–5cm deep kidney, and iii) human brain underlying intact scalp and skull. The physical models included layers of circulating tissue-mimicking liquids controlled at different temperatures to characterize our ability to quantify small changes in target temperature at depth under normothermic surface tissues. Results We report SAR patterns that characterize the sense region of a 2.6cm diameter receive antenna, and radiometric power measurements as a function of deep tissue temperature that quantify radiometer sensitivity. The data demonstrate: i) our ability to accurately track temperature rise in realistic tissue targets such as urine refluxed from prewarmed bladder into kidney, and 10°C drop in brain temperature underlying normothermic scalp and skull, and ii) long term accuracy and stability of ∓0.4°C over 4.5 hours as needed for monitoring core body temperature over extended surgery or monitoring effects of brown fat metabolism over an extended sleep/wake cycle. Conclusions A non-invasive sensor consisting of 2.6cm diameter receive antenna and integral 1.35GHz total power radiometer has demonstrated sufficient sensitivity to track clinically significant changes in temperature of deep tissue targets underlying normothermic surface

  14. Terra and Aqua MODIS Design, Radiometry, and Geometry in Support of Land Remote Sensing

    NASA Technical Reports Server (NTRS)

    Xiong, Xiaoxiong; Wolfe, Robert; Barnes, William; Guenther, Bruce; Vermote, Eric; Saleous, Nazmi; Salomonson, Vincent

    2011-01-01

    The NASA Earth Observing System (EOS) mission includes the construction and launch of two nearly identical Moderate Resolution Imaging Spectroradiometer (MODIS) instruments. The MODIS proto-flight model (PFM) is onboard the EOS Terra satellite (formerly EOS AM-1) launched on December 18, 1999 and hereafter referred to as Terra MODIS. Flight model-1 (FM1) is onboard the EOS Aqua satellite (formerly EOS PM-1) launched on May 04, 2002 and referred to as Aqua MODIS. MODIS was developed based on the science community s desire to collect multiyear continuous datasets for monitoring changes in the Earth s land, oceans and atmosphere, and the human contributions to these changes. It was designed to measure discrete spectral bands, which includes many used by a number of heritage sensors, and thus extends the heritage datasets to better understand both long- and short-term changes in the global environment (Barnes and Salomonson 1993; Salomonson et al. 2002; Barnes et al. 2002). The MODIS development, launch, and operation were managed by NASA/Goddard Space Flight Center (GSFC), Greenbelt, Maryland. The sensors were designed, built, and tested by Raytheon/ Santa Barbara Remote Sensing (SBRS), Goleta, California. Each MODIS instrument offers 36 spectral bands, which span the spectral region from the visible (0.41 m) to long-wave infrared (14.4 m). MODIS collects data at three different nadir spatial resolutions: 0.25, 0.5, and 1 km. Key design specifications, such as spectral bandwidths, typical scene radiances, required signal-to-noise ratios (SNR) or noise equivalent temperature differences (NEDT), and primary applications of each MODIS spectral band are summarized in Table 7.1. These parameters were the basis for the MODIS design. More details on the evolution of the NASA EOS and development of the MODIS instruments are provided in Chap. 1. This chapter focuses on the MODIS sensor design, radiometry, and geometry as they apply to land remote sensing. With near

  15. FOREWORD: The 9th International Conference on New Developments and Applications in Optical Radiometry (NEWRAD 2005)

    NASA Astrophysics Data System (ADS)

    Gröbner, Julian; Ikonen, Erkki

    2006-04-01

    The ninth NEWRAD Conference was held in Davos, Switzerland, between 16 and 19 October 2005. The Conference was organized by the Physikalisch- Meteorologisches Observatorium Davos, World Radiation Center (PMOD/WRC). The Conference was attended by 169 participants from five continents, which makes it the largest NEWRAD conference to date. The NEWRAD Conference followed the 10th international pyrheliometer comparison IPC-X, which is held every five years at PMOD/WRC. In addition, the 6th UVnet Workshop was held in connection with the NEWRAD Conference on 20 and 21 October. The NEWRAD Conference brings together people from the national metrology institutes and the principal user communities of advanced radiometry, including meteorological and remote-sensing communities. A total of 153 papers were presented, of which eight were keynote or invited talks, and there were 105 posters. Coffee breaks and extended lunch breaks created a stimulating atmosphere for lively discussions and exchange of ideas. Notwithstanding the excellent weather and the tantalizing surroundings of Davos, most participants managed to attend the poster sessions, which were organized during the noon lunch breaks. The conference proceedings can be downloaded from the NEWRAD 2005 website at www.pmodwrc.ch/newrad2005/pdfabstracts/Newrad_Proceedings_2005_A7.pdf. For this and future conferences, a new policy was adopted to publish a selected number of contributions in a special issue of Metrologia. The purpose of the change is to increase the overall impact of this journal. The NEWRAD Scientific Committee invited the contributions to this special issue on the basis of the quality of the extended abstracts, and later the submitted manuscripts were reviewed by the Committee members. On behalf of the Scientific Committee and all the participants, one of us (EI) wishes to thank Werner Schmutz and his colleagues from the Local Organizing Committee for arranging an excellent conference in the beautiful city of

  16. Assimilation of Stratospheric and Mesospheric Temperatures from MLS and SABER into a Global NWP Model

    DTIC Science & Technology

    2008-10-22

    MLS, red=SABER in three latitude bands of 50◦–70◦ S (left), ±10◦ (center) and 50◦–70◦ N (right), (a–c): average O- F ; ( d – f ) O- F standard deviation; (g–i...correlation coefficient between observations and forecast. Dotted curves in ( d – f ) plot corresponding O standard deviations only. summer, equatorial...113, D15S18, doi:10.1029/2007JD008807, 2008. Allen, D . R., Coy, L., Eckermann, S. D ., McCormack, J. P., Man- ney, G. L., Hogan, T. F ., and Kim, Y.-J

  17. SABER (TIMED) and MLS (UARS) Temperature Observations of Mesospheric and Stratospheric QBO and Related Tidal Variations

    NASA Technical Reports Server (NTRS)

    Huang, Frank T.; Mayr, Hans G.; Reber, Carl A.; Russell, James; Mlynczak, Marty; Mengel, John

    2006-01-01

    More than three years of temperature observations from the SABER (TIMED) and MLS WARS) instruments are analyzed to study the annual and inter-annual variations extending from the stratosphere into the upper mesosphere. The SABER measurements provide data from a wide altitude range (15 to 95 km) for the years 2002 to 2004, while the MLS data were taken in the 16 to 55 km altitude range a decade earlier. Because of the sampling properties of SABER and MLS, the variations with local solar time must be accounted for when estimating the zonal mean variations. An algorithm is thus applied that delineates with Fourier analysis the year-long variations of the migrating tides and zonal mean component. The amplitude of the diurnal tide near the equator shows a strong semiannual periodicity with maxima near equinox, which vary from year to year to indicate the influence from the Quasi-biennial Oscillation (QBO) in the zonal circulation. The zonal mean QBO temperature variations are analyzed over a range of latitudes and altitudes, and the results are presented for latitudes from 48"s to 48"N. New results are obtained for the QBO, especially in the upper stratosphere and mesosphere, and at mid-latitudes. At Equatorial latitudes, the QBO amplitudes show local peaks, albeit small, that occur at different altitudes. From about 20 to 40 km, and within about 15" of the Equator, the amplitudes can approach 3S K for the stratospheric QBO or SQBO. For the mesospheric QBO or MQBO, we find peaks near 70 km, with temperature amplitudes reaching 3.5"K, and near 85 km, the amplitudes approach 2.5OK. Morphologically, the amplitude and phase variations derived from the SABER and MLS measurements are in qualitative agreement. The QBO amplitudes tend to peak at the Equator but then increase again pole-ward of about 15" to 20'. The phase progression with altitude varies more gradually at the Equator than at mid-latitudes. A comparison of the observations with results from the Numerical Spectral

  18. Comments on the paper: M. Pawlak, K. Strzałkowski, Identification of the photoluminescence response in the frequency domain modulated infrared radiometry signal of ZnTe:Cr bulk crystal, Infrared Phys. Technol. 78 (2016) 190-194

    NASA Astrophysics Data System (ADS)

    Pawlak, M.

    2017-09-01

    The frequency-domain expression for the photoluminescence signal SPL (the photocarrier radiometry signal which is the form of the near infrared photoluminescence) which consists of the discrete lifetimes can be written as following [1

  19. Detection of Dental Secondary Caries Using Frequency-Domain Infrared Photothermal Radiometry (PTR) and Modulated Luminescence (LUM)

    NASA Astrophysics Data System (ADS)

    Kim, J.; Mandelis, A.; Matvienko, A.; Abrams, S.; Amaechi, B. T.

    2012-11-01

    The ability of frequency-domain photothermal radiometry (PTR) and modulated luminescence (LUM) to detect secondary caries is presented. Signal behavior upon sequential demineralization and remineralization of a spot (diameter ~1 mm) on a vertical wall of sectioned tooth samples was investigated experimentally. From these studies, it was found that PTR-LUM signals change, showing a certain pattern upon progressive demineralization and remineralization. PTR amplitudes slightly decreased upon progressive demineralization and slightly increased upon subsequent remineralization. The PTR phase increased during both demineralization and remineralization. LUM amplitudes exhibit a decreasing trend at excitation/probe distances larger than 200 μm away from the edge for both demineralization and remineralization; however, at locations close to the edge (up to ~200 μm), LUM signals slightly decrease upon demineralization and slightly increase during subsequent remineralization.

  20. An absolute calibration method of an ethyl alcohol biosensor based on wavelength-modulated differential photothermal radiometry.

    PubMed

    Liu, Yi Jun; Mandelis, Andreas; Guo, Xinxin

    2015-11-01

    In this work, laser-based wavelength-modulated differential photothermal radiometry (WM-DPTR) is applied to develop a non-invasive in-vehicle alcohol biosensor. WM-DPTR features unprecedented ethanol-specificity and sensitivity by suppressing baseline variations through a differential measurement near the peak and baseline of the mid-infrared ethanol absorption spectrum. Biosensor signal calibration curves are obtained from WM-DPTR theory and from measurements in human blood serum and ethanol solutions diffused from skin. The results demonstrate that the WM-DPTR-based calibrated alcohol biosensor can achieve high precision and accuracy for the ethanol concentration range of 0-100 mg/dl. The high-performance alcohol biosensor can be incorporated into ignition interlocks that could be fitted as a universal accessory in vehicles in an effort to reduce incidents of drinking and driving.

  1. Characterizing back surface loss of skin thickness and presence of corrosion by time-resolved infrared radiometry

    NASA Astrophysics Data System (ADS)

    Maclachlan Spicer, Jane W.; Kerns, W. D.; Osiander, Robert; Murphy, John C.

    1993-12-01

    This paper describes the use of time-resolved infrared radiometry (TRIR) to identify characteristic temperature-time signatures resulting from different subsurface thermal structures in aging aircraft. Central to the TRIR technique is the analysis of the temperature- time signatures at various locations as a step heating pulse is applied to the structure. Of particular interest is determining whether a signature can be identified which discriminates the presence of corrosion product from the simple thinning of the aircraft skin as might occur as a result of a previous repair. A technique is proposed which implements both area and localized heating sources. The area heating source provides one-dimensional heating of the specimen and allows suspect areas to be rapidly detected. A localized heating source is then used to further characterize the suspect regions.

  2. An absolute calibration method of an ethyl alcohol biosensor based on wavelength-modulated differential photothermal radiometry

    NASA Astrophysics Data System (ADS)

    Liu, Yi Jun; Mandelis, Andreas; Guo, Xinxin

    2015-11-01

    In this work, laser-based wavelength-modulated differential photothermal radiometry (WM-DPTR) is applied to develop a non-invasive in-vehicle alcohol biosensor. WM-DPTR features unprecedented ethanol-specificity and sensitivity by suppressing baseline variations through a differential measurement near the peak and baseline of the mid-infrared ethanol absorption spectrum. Biosensor signal calibration curves are obtained from WM-DPTR theory and from measurements in human blood serum and ethanol solutions diffused from skin. The results demonstrate that the WM-DPTR-based calibrated alcohol biosensor can achieve high precision and accuracy for the ethanol concentration range of 0-100 mg/dl. The high-performance alcohol biosensor can be incorporated into ignition interlocks that could be fitted as a universal accessory in vehicles in an effort to reduce incidents of drinking and driving.

  3. Quantitative Carrier Density Wave Imaging in Silicon Solar Cells Using Photocarrier Radiometry and Lock-in Carrierography

    NASA Astrophysics Data System (ADS)

    Sun, Q. M.; Melnikov, A.; Mandelis, A.

    2016-04-01

    InGaAs camera-based low-frequency homodyne and high-frequency heterodyne lock-in carrierographies (LIC) are introduced for spatially resolved imaging of optoelectronic properties of Si solar cells. Based on the full theory of solar cell photocarrier radiometry (PCR), several simplification steps were performed aiming at the open circuit case, and a concise expression of the base minority carrier density depth profile was obtained. The model shows that solar cell PCR/LIC signals are mainly sensitive to the base minority carrier lifetime. Both homodyne and heterodyne frequency response data at selected locations on a mc-Si solar cell were used to extract the local base minority carrier lifetimes by best fitting local experimental data to theory.

  4. Non-mechanical optical path switching and its application to dual beam spectroscopy including gas filter correlation radiometry

    NASA Technical Reports Server (NTRS)

    Sachse, Glen W. (Inventor); Wang, Liang-Guo (Inventor)

    1992-01-01

    A non-mechanical optical switch is developed for alternately switching a monochromatic or quasi-monochromatic light beam along two optical paths. A polarizer polarizes light into a single, e.g., vertical component which is then rapidly modulated into vertical and horizontal components by a polarization modulator. A polarization beam splitter then reflects one of these components along one path and transmits the other along the second path. In the specific application of gas filter correlation radiometry, one path is directed through a vacuum cell and one path is directed through a gas correlation cell containing a desired gas. Reflecting mirrors cause these two paths to intersect at a second polarization beam splitter which reflects one component and transmits the other to recombine them into a polarization modulated beam which can be detected by an appropriate single sensor.

  5. An absolute calibration method of an ethyl alcohol biosensor based on wavelength-modulated differential photothermal radiometry

    SciTech Connect

    Liu, Yi Jun; Mandelis, Andreas; Guo, Xinxin

    2015-11-15

    In this work, laser-based wavelength-modulated differential photothermal radiometry (WM-DPTR) is applied to develop a non-invasive in-vehicle alcohol biosensor. WM-DPTR features unprecedented ethanol-specificity and sensitivity by suppressing baseline variations through a differential measurement near the peak and baseline of the mid-infrared ethanol absorption spectrum. Biosensor signal calibration curves are obtained from WM-DPTR theory and from measurements in human blood serum and ethanol solutions diffused from skin. The results demonstrate that the WM-DPTR-based calibrated alcohol biosensor can achieve high precision and accuracy for the ethanol concentration range of 0-100 mg/dl. The high-performance alcohol biosensor can be incorporated into ignition interlocks that could be fitted as a universal accessory in vehicles in an effort to reduce incidents of drinking and driving.

  6. Satellite Altimetry And Radiometry for Inland Hydrology, Coastal Sea-Level And Environmental Studies

    NASA Astrophysics Data System (ADS)

    Tseng, Kuo-Hsin

    In this study, we demonstrate three environmental-related applications employing altimetry and remote sensing satellites, and exemplify the prospective usage underlying the current progressivity in mechanical and data analyzing technologies. Our discussion starts from the improved waveform retracking techniques in need for altimetry measurements over coastal and inland water regions. We developed two novel auxiliary procedures, namely the Subwaveform Filtering (SF) method and the Track Offset Correction (TOC), for waveform retracking algorithms to operationally detect altimetry waveform anomalies and further reduce possible errors in determination of the track offset. After that, we present two demonstrative studies related to the ionospheric and tropospheric compositions, respectively, as their variations are the important error sources for satellite electromagnetic signals. We firstly compare the total electron content (TEC) measured by multiple altimetry and GNSS sensors. We conclude that the ionosphere delay measured by Jason-2 is about 6-10 mm shorter than the GPS models. On the other hand, we use several atmospheric variables to study the climate change over high elevation areas. Five types of satellite data and reanalysis models were used to study climate change indicators. We conclude that the spatial distribution of temperature trend among data products is quite different, which is probably due to the choice of various time spans. Following discussions about the measuring techniques and relative bias between data products, we applied our improved altimetry techniques to three environmental science applications with helps of remote sensing imagery. We first manifest the detectability of hydrological events by satellite altimetry and radiometry. The characterization of one-dimensional (along-track) water boundary using former Backscattering Coefficient (BC) method is assisted by the two-dimensional (horizontal) estimate of water extent using the Moderate

  7. Ocean Colour Radiometry across the Southern Atlantic and South-Eastern Pacific

    NASA Astrophysics Data System (ADS)

    Rudorff, N. D.; Kampel, M.; Frouin, R. J.

    2011-12-01

    reference deck sensor. Rrs was estimated at 12 ocean colour bands from 412-681 nm. The best overall fit was between the M02 and MP02 methods. The mean normalized bias (MNB) ranged from 1.91% at 443 nm, with a normalized root mean square error (RMSE) of 35.83% and determination coefficient (R2) of 0.41; to 81.11% (MNB) at 681 nm with a RMSE of 72.86% and R2 of 0.52. The stations with the highest differences were the ones with a combination of adverse conditions, with stronger winds (>7.5 m/s) and higher waves (>2 m), but especially, high illumination variability. Clear sky or overcast conditions, even with strong winds (≈11 m/s) and waves, in general, still showed a good match. However, especially at overcast days, high offsets were observed at all spectra. Even with a simple method for the RSC, the M02 was considered efficient, providing accurate Rrs estimates, for the radiometry measurements sampled across the rough seas of the Southern Ocean.

  8. Using Infrared Laser Heterodyne Radiometry to Search for Methane in the Atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Passmore, Richard; Bowles, Neil; Weidmann, Damien; Smith, Kevin

    2010-05-01

    Introduction Methane has been detected in the atmosphere of Mars by several research teams in the last few years. Ground-based observations [1][2] and space-based instruments (e.g. the Planetary Fourier Transform spectrometer on Mars Express [3]) have reported low levels of methane gas (approximately 10 ppb) in the Martian atmosphere. Methane detection is important as its presence could imply a biological origin, and Martian methane sources are still unknown. However, current methane concentration measurements are at instruments' lower limits of detection. The viability of remote sensing using infrared laser heterodyne radiometry (LHR) to detect methane in the Martian atmosphere is investigated. The LHR technique allows high spectral resolution (greater than 0.001 cm-1) measurements over a narrow spectral range (~10 cm-1) when a distributed feedback quantum cascade laser (QCL) is used as local oscillator. The advantages of such an instrument, including its compact lightweight design, over current remote sensing spectral instruments are reviewed. The Laser Heterodyne Radiometer Laser heterodyne radiometers have been used extensively, and with much success, for atmospheric studies such as work on stratospheric ozone [4], mainly because the ultrahigh spectral resolution of the instrument allows fully resolved narrow molecular absorption line-shapes, which contain information on vertical concentration profiles. It has been shown that a carefully selected specific high resolution micro-window provides as much vertical profile information as a medium resolution radiometer covering a broad spectral range [5]. In addition to the high spectral resolution, the LHR is also extremely compact and robust and so has a significant advantage when targeting specific trace species over larger instruments such as high-resolution Fourier Transform spectrometers. Quantum Cascade Laser as Local Oscillator At the heart of the current generation infrared LHR is the use of a Quantum Cascade

  9. A new application of hyperspectral radiometry: the characterization of painted surfaces

    NASA Astrophysics Data System (ADS)

    Wang, Cong; Salvatici, Teresa; Camaiti, Mara; Del Ventisette, Chiara; Moretti, Sandro

    2016-04-01

    Hyperspectral sensors, working in the Visible-Near Infrared and Short Wave Infrared (VNIR-SWIR) regions, are widely employed for geological applications since they can discriminate many inorganic (e.g. mineral phases) and organic compounds (i.e. vegetations and soils) [1]. Their advantage is to work in the portion of the solar spectrum used for remote sensors. Some examples of application of the hyperspectral sensors to the conservation of cultural heritage are also known. These applications concern the detection of gypsum on historical buildings [2], and the monitoring of organic protective materials on stone surfaces [3]. On the contrary, hyperspectral radiometry has not been employed on painted surfaces. Indeed, the characterization of these surfaces is mainly performed with sophisticated, micro-destractive and time-consuming laboratory analyses (i.e. SEM-EDS, FTIR and, GC-MS spectroscopy) or through portable and non-invasive instruments (mid FTIR, micro Raman, XRF, FORS) which work in different spectral ranges [4,5]. In this work the discrimination of many organic and inorganic components from paintings was investigated through a hyperspectral spectroradiometer ,which works in the 350-2500 nm region. The reflectance spectra were collected by the contact reflectance probe, equipped with an internal light source with fixed geometry of illumination and shot. Several standards samples, selected among the most common materials of paintings, were prepared and analysed in order to collect reference spectra. The standards were prepared with powders of 7 pure pigments, films of 5 varnishes (natural and synthetic), and films of 3 dried binding media. Monochromatic painted surfaces have also been prepared and investigated to verify the identification of different compounds on the surface. The results show that the discrimination of pure products is possible in the VNIR-SWIR region, except for compounds with similar composition (e.g. natural resins such as dammar and

  10. Comparison between the Temperature Measurements by TIMED/SABER and Lidar in the Mid-Latitude

    NASA Technical Reports Server (NTRS)

    Xu, Jiyao; She, C. Y.; Yuan, Wei; Mertens, Chris; Mlynczak, Marty; Russell, James

    2005-01-01

    Comparisons of monthly-mean nighttime temperature profiles observed by the Sodium Lidar at Colorado State University and TIMED/SABER over passes are made. In the altitude range from 85 km to about 100 km, the two observations are in excellent agreement. Though within each other s error bars, important differences occur below 85 km in the entire year and above 100 km in the summer season. Possible reasons for these difference are high photon noise below 85 km in lidar observations, and less than accurate assumptions in the concentration of important chemical species like oxygen (and its quenching rate) in the SABER retrieval above 100 km. However, the two techniques both show the two-level mesopause thermal structure, with the times of change from one level to the other in excellent agreement. Comparison indicates that the high-level (winter) mesopause altitudes are also in excellent agreement between the two observations, though some difference may exist in the low-level (summer) mesopause altitudes between ground-based and satellite-borne data.

  11. Temperature Trends in the Polar Mesosphere between 2002-2007 using TIMED/SABER Data

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Kutepov, Alexander A.; Pesnell, William Dean; Latteck, Ralph; Russell, James M.

    2008-01-01

    The TIMED Satellite was launched on December 7, 2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The TIMED/SABER instrument is a limb scanning infrared radiometer designed to measure a large number of minor constituents as well as the temperature of the region. In this study, we have concentrated on the polar mesosphere, to investigate the temperature characteristics as a function of spatial and temporal considerations. We used the recently revised SABER dataset (1.07) that contains improved temperature retrievals in the Earth polar summer regions. Weekly averages are used to make comparisons between the winter and summer, as well as to study the variability in different quadrants of each hemisphere. For each year studied, the duration of polar summer based on temperature measurements compares favorably with the PMSE (Polar Mesospheric Summer Echoes) season measured by radar at the ALOMAR Observatory in Norway (69 N). The PMSE period should also define the summer period suitable for the occurrence of polar mesospheric clouds. The unusual short and relatively warm polar summer in the northern hemisphere

  12. Temperature Trends in the Polar Mesosphere between 2002-2007 using TIMED/SABER Data

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Kutepov, Alexander A.; Pesnell, William Dean; Latteck, Ralph; Russell, James M.

    2008-01-01

    The TIMED Satellite was launched on December 7, 2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The TIMED/SABER instrument is a limb scanning infrared radiometer designed to measure a large number of minor constituents as well as the temperature of the region. In this study, we have concentrated on the polar mesosphere, to investigate the temperature characteristics as a function of spatial and temporal considerations. We used the recently revised SABER dataset (1.07) that contains improved temperature retrievals in the Earth polar summer regions. Weekly averages are used to make comparisons between the winter and summer, as well as to study the variability in different quadrants of each hemisphere. For each year studied, the duration of polar summer based on temperature measurements compares favorably with the PMSE (Polar Mesospheric Summer Echoes) season measured by radar at the ALOMAR Observatory in Norway (69 N). The PMSE period should also define the summer period suitable for the occurrence of polar mesospheric clouds. The unusual short and relatively warm polar summer in the northern hemisphere

  13. Microwave-derived soil moisture over Mediterranean land uses: from ground-based radiometry to SMOS first observations

    NASA Astrophysics Data System (ADS)

    Saleh, Kauzar; Antolín, Carmen; Juglea, Silvia; Kerr, Yann; Millán-Scheiding, Cristina; Novello, Nathalie; Pardé, Mickael; Wigneron, Jean-Pierre; Zribi, Mehrez; López-Baeza, Ernesto

    2010-05-01

    This communication will present the main results of a series of airborne and ground-based experiments conducted at the Valencia Anchor Station (VAS) site for the implementation of the SMOS emission model L-MEB (L-band Microwave Emission model of the Biosphere, Wigneron et al., 2007), and will evaluate the performance of L-MEB against SMOS measurements. The L-MEB model has been implemented in the context of the SMOS mission and through numerous radiometry experiments over different land uses. Within L-MEB, each land use is characterised by model parameterisations that are used to describe the radiative transfer at L-band. They describe, for instance, the attenuation properties of different canopies, or the effect of soil roughness on the surface emission. In recent years, the Valencia Anchor Station site (VAS) has hosted various radiometry experiments. These were performed at different scales, from the plot scale to the regional scale (up to 50 km), using ground-based and airborne-based radiometry. The main results are discussed in this communication, and some preliminary comparisons with SMOS measurements are presented. 1) Ground-based experiments. MELBEX-I was a ground-radiometry experiment run in 2005 using the L-band radiometer EMIRAD over a plot of shrub land. We will present results from this experiment (Cano et al., 2009), that highlighted a constant (and small) contribution of Mediterranean shrub land to the overall emission, and investigated the role of exposed rocks in the surface emission. MELBEX-II was a ground-radiometry experiment run in 2007 using the EMIRAD L-band radiometer over a plot of vineyards throughout the whole vegetation cycle. Vineyards are the main land use at the VAS site, therefore parameterisations for vineyards are key for the validation of SMOS data at VAS. This communication will discuss, in particular, estimates of microwave surface roughness throughout the crop year, and changes in the canopy microwave properties throughout the

  14. Modeling Thermospheric Energetics: Implications of Cooling Rate Measurements by TIMED/SABER

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.; Qian, L.; Mlynczak, M. G.

    2012-12-01

    Infrared radiation from the lower thermosphere has a significant effect on thermospheric temperature throughout its altitude range. Energy deposited in the upper thermosphere is conducted downward to altitudes where collisional processes with heterogeneous molecules are effective in exciting radiative transitions. Thus, exospheric temperature is strongly influenced by the infrared cooling rates. Measurements from the SABER instrument on the TIMED satellite have provided the global distribution and temporal variation of the two most important cooling rates, from the 15-micron band of carbon dioxide, and the 5.3-micron band of nitric oxide, both excited in the thermosphere primarily by collisions with atomic oxygen [e.g., Mlynczak et al., JGR, 2010]. Because these measurements are of the cooling rate itself, they are nearly independent of assumptions concerning carbon dioxide or nitric oxide density, atomic oxygen density, temperature, and rate coefficients, and so provide strong constraints on global models. Simulations using the NCAR Thermosphere-Ionosphere-Mesosphere Electrodynamics General Circulation Model (TIME-GCM) have obtained reasonable agreement with global nitric oxide cooling rates, on daily and solar-cycle time scales alike [c.f., Qian et al., JGR, 2010; Solomon et al., JGR, 2012]. This may be somewhat surprising, or serendipitous, considering the complexity of the production and chemistry of thermospheric nitric oxide, but is a hopeful indication of the model's ability to describe thermospheric temperature structure and variability. However, initial model simulations of 15-micron carbon dioxide emission have been significantly lower than the SABER measurements. This indicates that there may be issues with the carbon dioxide densities, with the atomic oxygen density, or with the rate coefficient for their interaction. Simply increasing any of these to bring the cooling rate into agreement with SABER measurements will have the additional effect of

  15. Comment on "Photothermal radiometry parametric identifiability theory for reliable and unique nondestructive coating thickness and thermophysical measurements" [J. Appl. Phys. 121, 095101 (2017)

    NASA Astrophysics Data System (ADS)

    Krapez, J.-C.; Rigollet, F.

    2017-08-01

    A recent paper [Guo et al., J. Appl. Phys. 121, 095101 (2017)] intends to demonstrate that from the photothermal radiometry signal obtained on a coated opaque sample in 1D transfer, one should be able to identify separately the following three parameters of the coating: thermal diffusivity, thermal conductivity, and thickness. In this comment, it is shown that, in the considered experiment arrangement, these three parameters are correlated, the identifiability criterion is in error, and the thickness inferred therefrom is not trustable.

  16. Saber y conocer: Un plan para su ensenaza (To know and to be acquainted with: A teaching plan).

    ERIC Educational Resources Information Center

    Lizardi-Rivera, Carmen M.

    1995-01-01

    Focuses on how to teach English-speaking students of Spanish the practical distinction between the verbs, "saber" (to be cognizant of) and "conocer" (to be acquainted with). This article describes a solution proposed by K. Taylor for explaining the limits of the two verbs and examines similar proposals delineated in three other Spanish textbooks.…

  17. Chapter 4: Teachers' and Administrators' Perceptions of the Saber-Tooth Project Reform and of Their Changing Workplace Conditions.

    ERIC Educational Resources Information Center

    Doutis, Panayiotis; Ward, Phillip

    1999-01-01

    Describes changing workplace conditions encountered by middle school physical education teachers and administrators engaged in the Saber-Tooth Project, sharing data from interviews about their perspectives of this project. Findings are organized around the themes of collegiality, planning and assessment, and professionalism, all of which empowered…

  18. Multi-instrument gravity-wave measurements over Tierra del Fuego and the Drake Passage - Part 1: Potential energies and vertical wavelengths from AIRS, COSMIC, HIRDLS, MLS-Aura, SAAMER, SABER and radiosondes

    NASA Astrophysics Data System (ADS)

    Wright, Corwin J.; Hindley, Neil P.; Moss, Andrew C.; Mitchell, Nicholas J.

    2016-03-01

    Gravity waves in the terrestrial atmosphere are a vital geophysical process, acting to transport energy and momentum on a wide range of scales and to couple the various atmospheric layers. Despite the importance of these waves, the many studies to date have often exhibited very dissimilar results, and it remains unclear whether these differences are primarily instrumental or methodological. Here, we address this problem by comparing observations made by a diverse range of the most widely used gravity-wave-resolving instruments in a common geographic region around the southern Andes and Drake Passage, an area known to exhibit strong wave activity. Specifically, we use data from three limb-sounding radiometers (Microwave Limb Sounder, MLS-Aura; HIgh Resolution Dynamics Limb Sounder, HIRDLS; Sounding of the Atmosphere using Broadband Emission Radiometry, SABER), the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) GPS-RO constellation, a ground-based meteor radar, the Advanced Infrared Sounder (AIRS) infrared nadir sounder and radiosondes to examine the gravity wave potential energy (GWPE) and vertical wavelengths (λz) of individual gravity-wave packets from the lower troposphere to the edge of the lower thermosphere ( ˜ 100 km). Our results show important similarities and differences. Limb sounder measurements show high intercorrelation, typically > 0.80 between any instrument pair. Meteor radar observations agree in form with the limb sounders, despite vast technical differences. AIRS and radiosonde observations tend to be uncorrelated or anticorrelated with the other data sets, suggesting very different behaviour of the wave field in the different spectral regimes accessed by each instrument. Evidence of wave dissipation is seen, and varies strongly with season. Observed GWPE for individual wave packets exhibits a log-normal distribution, with short-timescale intermittency dominating over a well-repeated monthly-median seasonal

  19. Petroscirtes pylei, a new saber-toothed blenny from the Fiji Islands (Teleostei: Blenniidae)

    USGS Publications Warehouse

    Smith-Vaniz, W.F.

    2005-01-01

    Petroscirtes pylei is described from three specimens, 20.3-40.9 mm SL, obtained from a deep-water reef off Suva, Viti Levu, Fiji Islands. It is distinguished from all other congeners by its color pattern, including the presence of two dark body stripes, the lower one broadly extending onto the anal fin, and the dorsal fin with a broad, dark basal stripe, superimposed by a conspicuous white spot centered on the 4th spine. Among Petroscirtes, only the new species and P. springeri typically have 12 dorsal-fin spines but they are not closely related. The holotype was collected in 104-110 m, the second deepest depth record for a species of Petroscirtes. Discovery of this new species, and an apparently second new deep-water Petroscrites (uncollected), at a different Fijian reef indicates that our knowledge of the biodiversity of this habitat and of the saber-toothed blennies is very incomplete. Copyright ?? 2005 Magnolia Press.

  20. Evidence for paleotsunami deposits at Kefret Saber and El Alamein, Mediterranean coast of Egypt

    NASA Astrophysics Data System (ADS)

    Salama, Asem; Meghraoui, Mustapha; El Gabry, Mohamed; Maouche, Said; Hussein, Hichem; Korrat, Ibrahim

    2015-04-01

    Tsunami deposits and dragged large boulders are investigated along the Mediterranean coast of Egypt in the framework of the EC-Funded ASTARTE project (Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839) and the French-Egyptian IMHOTEP project. The targeted zones located west of Alexandria are selected according to historical earthquakes and related inundation events as recorded in archives. Field investigations include: 1) Coastal geomorphology along estuaries, wedge-protected and dune-protected lagunas, and terrace-platforms as potential sites for paleotsunami and boulder records and 2) Investigations of paleotsunamis deposits and their spatial distribution using trenching and coring. The two selected sites at Kefret Saber (immediately west of Marsah Matrouh town) and near El Alamein village are inner lagunas protected by 2 to 40-m-high dunes parallel to the shoreline. Five trenches and six cores dug in Kefret Saber and 1 trench in Alamein revealed an almost identical 5 to 10-cm-thick white sand unit with highly reworked fossil-rich and shells at about 20 to 40-cm-depth, intercalated in light brown laminated sandy and sandy-clay deposits. A total of 50 samples of organic deposits and charcoal fragments were collected from both sites, among which 20 samples have been dated. Dated charcoal in deposits above and below the white sand unit lead us to correlate with the 24 June 1870 major earthquake (M 7.5 - 8.0?) that generated a tsunami with the inundation of Alexandria harbor. Major seismic sources being along the Hellenic subduction zone and Cyprus arc, our progress study of paleotsunami deposits and their distribution along the Egyptian coast will help in a better constraint of the size and recurrence of tsunamis, and their propagation over the east Mediterranean regions.

  1. The variability of SE2 tide extracted from TIMED/SABER observations

    NASA Astrophysics Data System (ADS)

    Li, Xing; Wan, Weixing; Ren, Zhipeng; Yu, You

    2017-02-01

    Based on the temperature observations of the TIMED/Sounding of the Atmosphere using Broadband Emission Radiometry in mesosphere/lower thermosphere region (70-110 km altitudes) and at the low latitude and midlatitude (45°S-45°N) from 2002 to 2012, the variability of the nonmigrating tide SE2 with 1 day resolution is analyzed, using the method from Li et al. (2015). It is found that the climatological features (large-scale variability) of the SE2 tide are similar with the results from the previous research works. The SE2 tide manifests mainly at the low-mid latitudes around ±30°. The northern hemisphere tidal amplitudes below 110 km are larger than the southern hemisphere tide. SE2 peaks below 110 km mainly present between 100 and 110 km altitude. The tidal amplitudes below 110 km occur a north-south asymmetry about the equator in the annual variation: in the southern hemisphere, SE2 occurs with an obvious annual variation with a maximum of tidal amplitudes in December, while in the northern one, the semiannual variations with maximum at the equinoxes. Herein, owing to the high-resolution tidal data, we could research the short-term (day-to-day) variations of SE2. We found that the day-to-day variations manifest mainly at between 100 and 110 km altitudes; it increases gradually with latitudes, and it is stronger at the low-mid latitudes; it is relatively slightly stronger around solstices than equinoxes; and it does not present a remarkably interannual variation. The SE2 day-to-day variations may be composed by the absolute amplitudes' variance and the impact of the wave phases, and the latter ones are more important.

  2. Kinetic percolation

    NASA Astrophysics Data System (ADS)

    Heinson, W. R.; Chakrabarti, A.; Sorensen, C. M.

    2017-05-01

    We demonstrate that kinetic aggregation forms superaggregates that have structures identical to static percolation aggregates, and these superaggregates appear as a separate phase in the size distribution. Diffusion limited cluster-cluster aggregation (DLCA) simulations were performed to yield fractal aggregates with a fractal dimension of 1.8 and superaggregates with a fractal dimension of D = 2.5 composed of these DLCA supermonomers. When properly normalized to account for the DLCA fractal nature of their supermonomers, these superaggregates have the exact same monomer packing fraction, scaling law prefactor, and scaling law exponent (the fractal dimension) as percolation aggregates; these are necessary and sufficient conditions for same structure. The size distribution remains monomodal until these superaggregates form to alter the distribution. Thus the static percolation and the kinetic descriptions of gelation are now unified.

  3. In-vitro detection of artificial caries on vertical dental cavity walls using infrared photothermal radiometry and modulated luminescence

    NASA Astrophysics Data System (ADS)

    Kim, Jungho; Mandelis, Andreas; Abrams, Stephen H.; Vu, Jaclyn T.; Amaechi, Bennett T.

    2012-12-01

    The main objective of the study was to investigate the ability of frequency-domain photothermal radiometry (PTR) and modulated luminescence (LUM) to detect secondary caries lesions on the walls of restorations (wall lesions). Changes in experimental PTR-LUM signals due to sequential demineralization on entire vertical walls of sectioned tooth samples were investigated. In addition, transverse micro-radiography (TMR) analysis (used as a gold standard) was conducted to measure the degree of demineralization that occurred in each sample. Statistical correlation between TMR results and PTR-LUM signals was determined using Pearson's correlation coefficient. LUM signals were found to be dominated by the scattered component of the incident laser beam. The more clinically relevant cases of localized demineralization and remineralization on vertical walls were also investigated to examine whether PTR-LUM signals are sensitive to demineralization and remineralization of much smaller areas. The overall results demonstrated that PTR-LUM is sensitive to progressive demineralization and remineralization on vertical walls of sectioned tooth samples.

  4. The importance of signals in the Doppler broadening range for middle-atmospheric microwave wind and ozone radiometry

    NASA Astrophysics Data System (ADS)

    Rüfenacht, Rolf; Kämpfer, Niklaus

    2017-09-01

    Doppler microwave radiometry is a novel technique for the measurement of horizontal wind profiles at altitudes between 10 and 0.03 hPa, where there is a substantial lack of observations. All wind radiometers currently in use rely on ground-based observations of microwave radiation emitted by atmospheric ozone. Besides the well-known primary ozone layer in the stratosphere a secondary ozone layer forms near 10-3 hPa during nighttime. We show that the emission signal of this secondary ozone layer cannot be neglected for the retrieval of mesospheric winds and that it can even alter nighttime ozone retrievals. However, the present study also demonstrates that with a reasonably adequate representation of the atmospheric reality in the mesopause region bias-free wind retrievals throughout the entire sensitive altitude range of the instruments can be achieved during day and nighttime. By applying the improved ozone a priori setup to real observation data the average zonal wind difference to models was substantially reduced and a realistic diurnal cycle was reproduced. Moreover the presence of the high nighttime mesopause ozone signal could enable future retrievals of mean winds beyond the altitude range dominated by pressure broadening.

  5. Multiband fiber optic radiometry for measuring the temperature and emissivity of gray bodies of low or high emissivity.

    PubMed

    Sade, Sharon; Katzir, Abraham

    2004-03-20

    Infrared fiber optic radiometry was used for noncontact thermometry of gray bodies whose temperature was close to room temperature (40-70 degrees C). We selected three gray bodies, one with high emissivity (epsilon = 0.97), one with medium emissivity (epsilon = 0.71), and one with low emissivity (epsilon = 0.025). We carried out optimization calculations and measurements for a multiband fiber optic radiometer that consisted of a silver halide (AgClBr) infrared-transmitting fiber, a dual-band cooled infrared detector, and a set of 18 narrowband infrared filters that covered the 2-14-microm spectral range. We determined the optimal spectral range, the optimal number of filters to be used, and the optimal chopping scheme. Using these optimal conditions, we performed measurements of the three gray bodies and obtained an accuracy of better than 1 degrees C for body temperature and for room temperature. An accuracy of 0.03 was obtained for body emissivity.

  6. Dental depth profilometric diagnosis of pit & fissure caries using frequency-domain infrared photothermal radiometry and modulated laser luminescence

    NASA Astrophysics Data System (ADS)

    Jeon, R. J.; Mandelis, A.; Sanchez, V.; Abrams, S. H.

    2005-06-01

    Non-intrusive, non-contacting frequency-domain photothermal radiometry (FD-PTR or PTR) and frequency-domain luminescence (FD-LUM or LUM) have been used with 659- nm and 830-nm laser sources to detect artificial and natural sub-surface defects in human teeth. Fifty-two human teeth were examined with simultaneous measurements of PTR and LUM and compared to conventional diagnostic methods including continuous (dc) luminescence (DIAGNOdent), visual inspection and radiographs by calculating sensitivities and specificities. With the combined criteria of four PTR and LUM signals (two amplitudes and two phases), it was found that the sensitivity of this method was much higher than any of the other methods used in this study, whereas the specificity was comparable to that of dc luminescence diagnostics. Therefore, PTR and LUM, used together as a combined technique, have the potential to be a reliable tool to diagnose early pit and fissure caries and could provide detailed information about deep lesions with its depth profilometric character. Also, from experiments with natural or artificial defects, some depth profilometric characteristics were confirmed.

  7. Enabling compact MMIC-based frontends for millimeter-wave imaging radar and radiometry at 94 and 210 GHz

    NASA Astrophysics Data System (ADS)

    Kallfass, Ingmar; Tessmann, Axel; Leuther, Arnulf; Kuri, Michael; Riessle, Markus; Zink, Martin; Massler, Hermann; Schlechtweg, Michael; Ambacher, Oliver

    2008-10-01

    We report on MMIC-based analog frontend components for imaging radar and radiometry at high millimeter-wave frequencies. The MMICs are realized in our metamorphic HEMT technology. In W-band, the focus is on analog frontends with multi-pixel capability. A compact four-channel receiver module based on four single-chip heterodyne receiver MMICs achieves a noise figure of 4.2 dB and a conversion gain of 7 dB. A W-band five-to-one switch MMIC with less than 3.5 dB insertion loss addresses four antenna ports and uses an integrated reference termination for pixel normalization. Both components operate in a frequency range from 75 to 100 GHz, making them suitable for broadband imaging systems with high geometrical resolution. After an overview of MMIC amplifier performance over the entire millimeter-wave frequency range, we present a chip set for imaging radar at 210 GHz, comprising linear and frequency-translating circuits.

  8. High-accuracy detector calibration in the 3-1500 eV spectral range at the PTB radiometry laboratory.

    PubMed

    Scholze, F; Henneken, H; Kuschnerus, P; Rabus, H; Richter, M; Ulm, G

    1998-05-01

    State-of-the-art detector calibration in the UV/VUV and soft X-ray spectral ranges at the Physikalisch-Technische Bundesanstalt (PTB) is based on the primary detector standard SYRES, a cryogenic electrical substitution radiometer capable of measuring radiant power of a few micro W. At the PTB radiometry laboratory at the synchrotron radiation facility BESSY, two dedicated beamlines are operated, providing monochromatic radiation of high spectral purity, high radiant power and tunable photon energy in the 3-1500 eV range. The spectral responsivity of detectors, e.g. photodiodes, can be measured with a relative uncertainty of about 1% by direct comparison with SYRES, as will be demonstrated for PtSi/Si and GaAsP/Au Schottky and silicon n-on-p photodiodes. The calibration of photon-counting detectors traceable to SYRES can by accomplished by exploiting the unique capability to scale the spectral photon flux over several orders of magnitude by changing the stored electron current. Calibrations of CCDs and photomultipliers are presented as examples.

  9. Dental depth profilometry using simultaneous frequency-domain infrared photothermal radiometry and laser luminescence for the diagnosis of dental caries

    NASA Astrophysics Data System (ADS)

    Nicolaides, Lena; Garcia, Jose A.; Mandelis, Andreas; Abrams, Stephen H.

    2001-04-01

    Frequency-domain IR photothermal radiometry is introduced as a dynamic dental diagnostic tool and its main features are compared with modulated laser luminescence for quantifying sound and carious enamel or dentin. Dental caries found in the fissures or grooves of teeth is very difficult to diagnose or quantify with the present clinical techniques. Visual examination and dental radiographs do not detect the presence of decay until there has been significant carious destruction of the tooth. A high-spatial-resolution dynamic experimental imaging set-up, which can provide simultaneous measurements of laser-induced frequency-domain IR photothermal radiometric and luminescence signals form defects in teeth, was developed. Following optical absorption of laser photons, the new set-up can monitor simultaneously and independently the non-radiative conversion, and the radiative de-excitation in turbid media such as hard dental tissue. This work is intended to show the complementarity between modulated luminescence and photothermal frequency scans in detecting carious lesions in teeth. A sound extracted molar with a dentin-enamel interface was introduced to examine the depth profilometric abilities of the method. Occlusal surfaces of teeth with potential areas of demineralization or carious destruction in the fissures were examined and compared to the signals produced by the sound enamel establishing the depth profilometric abilities of the method. The significance to clinical dentistry lies in the potential of this technique to detect and monitor early carious lesions in the pits and fissures of teeth.

  10. Progress in theoretical, experimental, and computational investigations in turbid tissue phantoms and human teeth using laser infrared photothermal radiometry

    NASA Astrophysics Data System (ADS)

    Mandelis, Andreas

    2002-03-01

    This paper reviews and describes the state-of-the-art in the development of frequency-domain infrared photothermal radiometry (FD-PTR) for biomedical and dental applications. The emphasis is placed on the measurement of the optical and thermal properties of tissue-like materials using FD-PTR. A rigorous three-dimensional thermal-wave formulation with three-dimensional diffuse and coherent photon-density-wave sources is presented, and is applied to data from model tissue phantoms and dental enamel samples. The combined theoretical, experimental and computational methodology shows good promise with regard to its analytical ability to measure optical properties of turbid media uniquely, as compared to PPTR, which exhibits uniqueness problems. From data sets obtained with calibrated test phantoms, the reduced optical scattering and absorption coefficients were found to be within 20% and 10%, respectively, from the independently derived values using Mie scattering theory and spectrophotometric measurements. Furthermore, the state-of-the-art and recent developments in applications of laser infrared FD-PTR to dental caries research is described, with examples and histological studies from carious dental tissue. The correlation of PTR signals with modulated dental luminescence is discussed as a very promising potential quantitative methodology for the clinical diagnosis of sub-surface incipient dental caries. The application of the turbid-medium thermal-wave model to the measurement of the optical absorption and scattering coefficients of enamel is also presented.

  11. Satellite microwave scanner radiometry data using for analysis of statistics of tropical cyclone generation criterion in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Goncharenko, Igor V.; Rostovtseva, Vera V.

    2006-11-01

    Investigation of the conditions resulting in generation of tropical cyclones is the important scientific and practical problem. The suggested temperature-humidity criterion (Pelevin criterion) allows estimating the possibility of tropical cyclone generation using values of ocean surface temperature, water vapor amount above the ocean surface and Coriolis parameter depending on the place latitude. All these parameters can be measured with success by microwave radiometry methods, satellite microwave scanner data giving the possibility to examine the distribution of these physical parameters over different aquatoria of World Ocean and to follow their alteration within the day. To realize this possibility the program of the satellite information processing was developed allowing to estimate such parameters as ocean surface temperature, wind velocity, water vapor amount, amount of water in liquid state (fog), presence and intensity of raining in different areas of World ocean and to obtain the values of Pelevin criterion. Processing measurements of DMSP satellites system there is an opportunity to estimate the abovementioned parameters values and Pelevin criterion twice a day with the spatial resolution of 25X25 km. Distribution of Pelevin criterion value in the tropical Atlantic was analyzed for 2002 and 2004, spatial and time characteristics of statistics of this distribution being revealed. Rather good correlation between the criterion values and the frequency of tropical cyclones generation taking place in Northern Atlantic at these time periods is shown.s

  12. Comparisons of Reflectance Targets at the Above Water Radiometry Workshop on Long Island Sound, August 4 - 6, 2010

    NASA Astrophysics Data System (ADS)

    Johnson, B.; Fargion, G. S.; Saunders, R. D.; Ondrusek, M. E.

    2012-12-01

    On August 4-5, 2010, members from the satellite remote sensing community participated in a workshop off the coast of Long Island, New York. The participant's objective was to interpret and implement recently published protocols for measuring normalized, water-leaving spectral radiances by above-water in situ radiometry and compare the results. Each research team applied the protocols to the measurement of the water's surface and three reflectance standard targets supplied by NIST - a white and a gray diffuse reflectance target and a blue ground-glass target. The reflectance values of the water's surface and the test targets were derived and analyzed by each team. We report on the workshop detailing the methods for comparison of the participant's results of the test targets. The workshop served as a preparation for the vigorous validation activities that occurred following the launch of the Visible Infrared Imager Radiometer Suite (VIIRS). Above water, in situ, radiometric measurements using uncalibrated radiometers and standard diffuse reflectance targets are one method used by researchers to validate the VIIRS data products. The Joint Polar Satellite System (JPSS) office provided support to NIST for this work (NA12AANEG0230).

  13. Photocarrier Radiometry Investigation of Light-Induced Degradation of Boron-Doped Czochralski-Grown Silicon Without Surface Passivation

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Li, Bincheng

    2016-04-01

    Light-induced degradation (LID) effects of boron-doped Cz silicon wafers without surface passivation are investigated in details by photocarrier radiometry (PCR). The resistivity of all samples is in the range of 0.006 Ω {\\cdot } {cm} to 38 Ω {\\cdot } {cm}. It is found that light-induced changes in surface state occupation have a great effect on LID under illumination. With the increasing contribution of light-induced changes in surface state occupation, the generation rate of the defect decreases. The light-induced changes in surface state occupation and light-induced degradation dominate the temporal behaviors of the excess carrier density of high- and low-resistivity Si wafers, respectively. Moreover, the temporal behaviors of PCR signals of these samples under laser illumination with different powers, energy of photons, and multiple illuminations were also analyzed to understand the light-induced change of material properties. Based on the nonlinear dependence of PCR signal on the excitation power, a theoretical model taking into account both light-induced changes in surface state occupation and LID processes was proposed to explain those temporal behaviors.

  14. Simultaneous measurement of temperature and emissivity of lunar regolith simulant using dual-channel millimeter-wave radiometry.

    PubMed

    McCloy, J S; Sundaram, S K; Matyas, J; Woskov, P P

    2011-05-01

    Millimeter wave (MMW) radiometry can be used for simultaneous measurement of emissivity and temperature of materials under extreme environments (high temperature, pressure, and corrosive environments). The state-of-the-art dual channel MMW passive radiometer with active interferometric capabilities at 137 GHz described here allows for radiometric measurements of sample temperature and emissivity up to at least 1600 °C with simultaneous measurement of sample surface dynamics. These capabilities have been used to demonstrate dynamic measurement of melting of powders of simulated lunar regolith and static measurement of emissivity of solid samples. The paper presents the theoretical background and basis for the dual-receiver system, describes the hardware in detail, and demonstrates the data analysis. Post-experiment analysis of emissivity versus temperature allows further extraction from the radiometric data of millimeter wave viewing beam coupling factors, which provide corroboratory evidence to the interferometric data of the process dynamics observed. These results show the promise of the MMW system for extracting quantitative and qualitative process parameters for industrial processes and access to real-time dynamics of materials behavior in extreme environments.

  15. Simultaneous measurement of temperature and emissivity of lunar regolith simulant using dual-channel millimeter-wave radiometry

    SciTech Connect

    McCloy, J. S.; Sundaram, S. K.; Matyas, J.; Woskov, P. P.

    2011-01-01

    Millimeter wave (MMW) radiometry can be used for simultaneous measurement of emissivity and temperature of materials under extreme environments (high temperature, pressure, and corrosive environments). The state-of-the-art dual channel MMW passive radiometer with active interferometric capabilities at 137 GHz described here allows for radiometric measurements of sample temperature and emissivity up to at least 1600 °C with simultaneous measurement of sample surface dynamics. These capabilities have been used to demonstrate dynamic measurement of melting of powders of simulated lunar regolith and static measurement of emissivity of solid samples. The paper presents the theoretical background and basis for the dual-receiver system, describes the hardware in detail, and demonstrates the data analysis. Post-experiment analysis of emissivity versus temperature allows further extraction from the radiometric data of millimeter wave viewing beam coupling factors, which provide corroboratory evidence to the interferometric data of the process dynamics observed. Finally, these results show the promise of the MMW system for extracting quantitative and qualitative process parameters for industrial processes and access to real-time dynamics of materials behavior in extreme environments.

  16. Tolrestat kinetics

    SciTech Connect

    Hicks, D.R.; Kraml, M.; Cayen, M.N.; Dubuc, J.; Ryder, S.; Dvornik, D.

    1984-10-01

    The kinetics of tolrestat, a potent inhibitor of aldose reductase, were examined. Serum concentrations of tolrestat and of total /sup 14/C were measured after dosing normal subjects and subjects with diabetes with /sup 14/C-labeled tolrestat. In normal subjects, tolrestat was rapidly absorbed and disappearance from serum was biphasic. Distribution and elimination t 1/2s were approximately 2 and 10 to 12 hr, respectively, after single and multiple doses. Unchanged tolrestat accounted for the major portion of /sup 14/C in serum. Radioactivity was rapidly and completely excreted in urine and feces in an approximate ratio of 2:1. Findings were much the same in subjects with diabetes. In normal subjects, the kinetics of oral tolrestat were independent of dose in the 10 to 800 mg range. Repetitive dosing did not result in unexpected cumulation. Tolrestat was more than 99% bound to serum protein; it did not compete with warfarin for binding sites but was displaced to some extent by high concentrations of tolbutamide or salicylate.

  17. Comparative Biomechanical Modeling of Metatherian and Placental Saber-Tooths: A Different Kind of Bite for an Extreme Pouched Predator

    PubMed Central

    Wroe, Stephen; Chamoli, Uphar; Parr, William C. H.; Clausen, Philip; Ridgely, Ryan; Witmer, Lawrence

    2013-01-01

    Questions surrounding the dramatic morphology of saber-tooths, and the presumably deadly purpose to which it was put, have long excited scholarly and popular attention. Among saber-toothed species, the iconic North American placental, Smilodon fatalis, and the bizarre South American sparassodont, Thylacosmilus atrox, represent extreme forms commonly forwarded as examples of convergent evolution. For S. fatalis, some consensus has been reached on the question of killing behaviour, with most researchers accepting the canine-shear bite hypothesis, wherein both head-depressing and jaw closing musculatures played a role in delivery of the fatal bite. However, whether, or to what degree, T. atrox may have applied a similar approach remains an open question. Here we apply a three-dimensional computational approach to examine convergence in mechanical performance between the two species. We find that, in many respects, the placental S. fatalis (a true felid) was more similar to the metatherian T. atrox than to a conical-toothed cat. In modeling of both saber-tooths we found that jaw-adductor-driven bite forces were low, but that simulations invoking neck musculature revealed less cranio-mandibular stress than in a conical-toothed cat. However, our study also revealed differences between the two saber-tooths likely reflected in the modus operandi of the kill. Jaw-adductor-driven bite forces were extremely weak in T. atrox, and its skull was even better-adapted to resist stress induced by head-depressors. Considered together with the fact that the center of the arc described by the canines was closer to the jaw-joint in Smilodon, our results are consistent with both jaw-closing and neck musculature playing a role in prey dispatch for the placental, as has been previously suggested. However, for T. atrox, we conclude that the jaw-adductors probably played no major part in the killing bite. We propose that the metatherian presents a more complete commitment to the already

  18. Comparative Biomechanical Modeling of Metatherian and Placental Saber-Tooths: A Different Kind of Bite for an Extreme Pouched Predator.

    PubMed

    Wroe, Stephen; Chamoli, Uphar; Parr, William C H; Clausen, Philip; Ridgely, Ryan; Witmer, Lawrence

    2013-01-01

    Questions surrounding the dramatic morphology of saber-tooths, and the presumably deadly purpose to which it was put, have long excited scholarly and popular attention. Among saber-toothed species, the iconic North American placental, Smilodon fatalis, and the bizarre South American sparassodont, Thylacosmilus atrox, represent extreme forms commonly forwarded as examples of convergent evolution. For S. fatalis, some consensus has been reached on the question of killing behaviour, with most researchers accepting the canine-shear bite hypothesis, wherein both head-depressing and jaw closing musculatures played a role in delivery of the fatal bite. However, whether, or to what degree, T. atrox may have applied a similar approach remains an open question. Here we apply a three-dimensional computational approach to examine convergence in mechanical performance between the two species. We find that, in many respects, the placental S. fatalis (a true felid) was more similar to the metatherian T. atrox than to a conical-toothed cat. In modeling of both saber-tooths we found that jaw-adductor-driven bite forces were low, but that simulations invoking neck musculature revealed less cranio-mandibular stress than in a conical-toothed cat. However, our study also revealed differences between the two saber-tooths likely reflected in the modus operandi of the kill. Jaw-adductor-driven bite forces were extremely weak in T. atrox, and its skull was even better-adapted to resist stress induced by head-depressors. Considered together with the fact that the center of the arc described by the canines was closer to the jaw-joint in Smilodon, our results are consistent with both jaw-closing and neck musculature playing a role in prey dispatch for the placental, as has been previously suggested. However, for T. atrox, we conclude that the jaw-adductors probably played no major part in the killing bite. We propose that the metatherian presents a more complete commitment to the already

  19. Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of brown fat metabolism

    NASA Astrophysics Data System (ADS)

    Rodrigues, Dario B.; Maccarini, Paolo F.; Salahi, Sara; Colebeck, Erin; Topsakal, Erdem; Pereira, Pedro J. S.; Limão-Vieira, Paulo; Stauffer, Paul R.

    2013-02-01

    Background: Brown adipose tissue (BAT) plays an important role in whole body metabolism and could potentially mediate weight gain and insulin sensitivity. Although some imaging techniques allow BAT detection, there are currently no viable methods for continuous acquisition of BAT energy expenditure. We present a non-invasive technique for long term monitoring of BAT metabolism using microwave radiometry. Methods: A multilayer 3D computational model was created in HFSSTM with 1.5 mm skin, 3-10 mm subcutaneous fat, 200 mm muscle and a BAT region (2-6 cm3) located between fat and muscle. Based on this model, a log-spiral antenna was designed and optimized to maximize reception of thermal emissions from the target (BAT). The power absorption patterns calculated in HFSSTM were combined with simulated thermal distributions computed in COMSOL® to predict radiometric signal measured from an ultra-low-noise microwave radiometer. The power received by the antenna was characterized as a function of different levels of BAT metabolism under cold and noradrenergic stimulation. Results: The optimized frequency band was 1.5-2.2 GHz, with averaged antenna efficiency of 19%. The simulated power received by the radiometric antenna increased 2-9 mdBm (noradrenergic stimulus) and 4-15 mdBm (cold stimulus) corresponding to increased 15-fold BAT metabolism. Conclusions: Results demonstrated the ability to detect thermal radiation from small volumes (2-6 cm3) of BAT located up to 12 mm deep and to monitor small changes (0.5 °C) in BAT metabolism. As such, the developed miniature radiometric antenna sensor appears suitable for non-invasive long term monitoring of BAT metabolism.

  20. In vivo characterization of structural and optical properties of human skin by combined photothermal radiometry and diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Verdel, Nina; Marin, Ana; Vidovič, Luka; Milanič, Matija; Majaron, Boris

    2017-02-01

    We have combined two optical techniques to enable simultaneous assessment of structure and composition of human skin in vivo: Pulsed photothermal radiometry (PPTR), which involves measurements of transient dynamics in midinfrared emission from sample surface after exposure to a light pulse, and diffuse reflectance spectroscopy (DRS) in visible part of the spectrum. Namely, while PPTR is highly sensitive to depth distribution of selected absorbers, DRS provides spectral information and thus enables differentiation between various chromophores. The accuracy and robustness of the inverse analysis is thus considerably improved compared to use of either technique on its own. Our analysis approach is simultaneous multi-dimensional fitting of the measured PPTR signals and DRS with predictions from a numerical model of light-tissue interaction (a.k.a. inverse Monte Carlo). By using a three-layer skin model (epidermis, dermis, and subcutis), we obtain a good match between the experimental and modeling data. However, dividing the dermis into two separate layers (i.e., papillary and reticular dermis) helps to bring all assessed parameter values within anatomically and physiologically plausible intervals. Both the quality of the fit and the assessed parameter values depend somewhat on the assumed scattering properties for skin, which vary in literature and likely depend on subject's age and gender, anatomical site, etc. In our preliminary experience, simultaneous fitting of the scattering properties is possible and leads to considerable improvement of the fit. The described approach may thus have a potential for simultaneous determination of absorption and scattering properties of human skin in vivo.

  1. A First-Order Radiative Transfer Model for Microwave Radiometry of Forest Canopies at L-Band

    NASA Technical Reports Server (NTRS)

    Kurum, Mehmet; Lang, Roger H.; O'Neill, Peggy E.; Joseph, Alicia T.; Jackson, Thomas J.; Cosh, Michael H.

    2011-01-01

    In this study, a first-order radiative transfer (RT) model is developed to more accurately account for vegetation canopy scattering by modifying the basic Tau-Omega model (the zero-order RT solution). In order to optimally utilize microwave radiometric data in soil moisture (SM) retrievals over vegetated landscapes, a quantitative understanding of the relationship between scattering mechanisms within vegetation canopies and the microwave brightness temperature is desirable. The first-order RT model is used to investigate this relationship and to perform a physical analysis of the scattered and emitted radiation from vegetated terrain. This model is based on an iterative solution (successive orders of scattering) of the RT equations up to the first order. This formulation adds a new scattering term to the . model. The additional term represents emission by particles (vegetation components) in the vegetation layer and emission by the ground that is scattered once by particles in the layer. The model is tested against 1.4-GHz brightness temperature measurements acquired over deciduous trees by a truck-mounted microwave instrument system called ComRAD in 2007. The model predictions are in good agreement with the data, and they give quantitative understanding for the influence of first-order scattering within the canopy on the brightness temperature. The model results show that the scattering term is significant for trees and modifications are necessary to the . model when applied to dense vegetation. Numerical simulations also indicate that the scattering term has a negligible dependence on SM and is mainly a function of the incidence angle and polarization of the microwave observation. Index Terms Emission,microwave radiometry, scattering, soil, vegetation.

  2. A First-Order Radiative Transfer Model for Microwave Radiometry of Forest Canopies at L-Band

    NASA Technical Reports Server (NTRS)

    Kurum, Mehmet; Lang, Roger H.; O'Neill, Peggy E.; Joseph, Alicia T.; Jackson, Thomas J.; Cosh, Michael H.

    2011-01-01

    In this study, a first-order radiative transfer (RT) model is developed to more accurately account for vegetation canopy scattering by modifying the basic Tau-Omega model (the zero-order RT solution). In order to optimally utilize microwave radiometric data in soil moisture (SM) retrievals over vegetated landscapes, a quantitative understanding of the relationship between scattering mechanisms within vegetation canopies and the microwave brightness temperature is desirable. The first-order RT model is used to investigate this relationship and to perform a physical analysis of the scattered and emitted radiation from vegetated terrain. This model is based on an iterative solution (successive orders of scattering) of the RT equations up to the first order. This formulation adds a new scattering term to the . model. The additional term represents emission by particles (vegetation components) in the vegetation layer and emission by the ground that is scattered once by particles in the layer. The model is tested against 1.4-GHz brightness temperature measurements acquired over deciduous trees by a truck-mounted microwave instrument system called ComRAD in 2007. The model predictions are in good agreement with the data, and they give quantitative understanding for the influence of first-order scattering within the canopy on the brightness temperature. The model results show that the scattering term is significant for trees and modifications are necessary to the . model when applied to dense vegetation. Numerical simulations also indicate that the scattering term has a negligible dependence on SM and is mainly a function of the incidence angle and polarization of the microwave observation. Index Terms Emission,microwave radiometry, scattering, soil, vegetation.

  3. Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of brown fat metabolism.

    PubMed

    Rodrigues, Dario B; Maccarini, Paolo F; Salahi, Sara; Colebeck, Erin; Topsakal, Erdem; Pereira, Pedro J S; Limão-Vieira, Paulo; Stauffer, Paul R

    2013-02-26

    Brown adipose tissue (BAT) plays an important role in whole body metabolism and could potentially mediate weight gain and insulin sensitivity. Although some imaging techniques allow BAT detection, there are currently no viable methods for continuous acquisition of BAT energy expenditure. We present a non-invasive technique for long term monitoring of BAT metabolism using microwave radiometry. A multilayer 3D computational model was created in HFSS™ with 1.5 mm skin, 3-10 mm subcutaneous fat, 200 mm muscle and a BAT region (2-6 cm(3)) located between fat and muscle. Based on this model, a log-spiral antenna was designed and optimized to maximize reception of thermal emissions from the target (BAT). The power absorption patterns calculated in HFSS™ were combined with simulated thermal distributions computed in COMSOL® to predict radiometric signal measured from an ultra-low-noise microwave radiometer. The power received by the antenna was characterized as a function of different levels of BAT metabolism under cold and noradrenergic stimulation. The optimized frequency band was 1.5-2.2 GHz, with averaged antenna efficiency of 19%. The simulated power received by the radiometric antenna increased 2-9 mdBm (noradrenergic stimulus) and 4-15 mdBm (cold stimulus) corresponding to increased 15-fold BAT metabolism. Results demonstrated the ability to detect thermal radiation from small volumes (2-6 cm(3)) of BAT located up to 12 mm deep and to monitor small changes (0.5 °C) in BAT metabolism. As such, the developed miniature radiometric antenna sensor appears suitable for non-invasive long term monitoring of BAT metabolism.

  4. Uncertainty Analysis of in situ Ocean Color Radiometry for the Vicarious Calibration of Ocean Color Satellite Sensors

    NASA Astrophysics Data System (ADS)

    Johnson, B.; Clark, D.; Feinholz, M.; Flora, S.; Franz, B.; Houlihan, T.; Mueller, J. A.; Parr, A. C.; Voss, K. J.; Yarbrough, M.

    2011-12-01

    Substantial effort has been invested by NASA to create and maintain a long-term, consistent, and calibrated time series of ocean color radiometry over multiple missions and satellite sensors. This is a very difficult measurement problem because the water-leaving radiance is a small fraction of the total radiance measured by the satellite sensor. As a result, the SI traceability of ocean color radiometric values relies completely on a vicarious calibration approach utilizing reference oceanic sites. A robust and rigorous uncertainty analysis of this data set is outstanding. Broadly speaking, there are three aspects to the uncertainty budget for the long-term time series of the global ocean color radiometric data set: the in situ radiometric time series, the in situ to satellite match-up time series for determination of the vicarious calibration gain coefficients, and the global, satellite derived values for water-leaving radiances (or remote sensing reflectances). The uncertainty budget has elements attributed to sensor characterization functions (which change in time), natural variability, and the veracity and efficacy of the measurement equations (including models and algorithms) that describe the complete methodology. We have recently undertaken a rigorous analysis of uncertainty of the global ocean color radiometric time series data set, emphasizing the in situ uncertainties and their impact on the ocean color time series. Our technical approach is to formulate and analyze measurement equations that model the relationships between the values of the measured quantities and the resulting uncertainties, thus establishing traceability of the values of the MOBY results to stated reference values. Uncertainty estimates are quantitative data products in and of themselves - documentation of discrepancies between results and associating these values with uncertainties is not a valid or sufficient approach. We will review the MOBY data set, explain our uncertainty model

  5. Analyse du potentiel de la radiometrie infrarouge thermique pour la caracterisation des nuages de glace en Arctique

    NASA Astrophysics Data System (ADS)

    Blanchard, Yann

    An important goal, within the context of improving climate change modelling, is to enhance our understanding of aerosols and their radiative effects (notably their indirect impact as cloud condensation nuclei). The cloud optical depth (COD) and average ice particle size of thin ice clouds (TICs) are two key parameters whose variations could strongly influence radiative effects and climate in the Arctic environment. Our objective was to assess the potential of using multi-band thermal radiance measurements of zenith sky radiance for retrieving COD and effective particle diameter (Deff) of TICs in the Arctic. We analyzed and quantified the sensitivity of thermal radiance on many parameters, such as COD, Deff, water vapor content, cloud bottom altitude and thickness, size distribution and shape. Using the sensitivity of IRT to COD and Deff, the developed retrieval technique is validated in comparison with retrievals from LIDAR and RADAR. Retrievals were applied to ground-based thermal infrared data acquired for 100 TICs at the high-Arctic PEARL observatory in Eureka, Nunavut, Canada and were validated using AHSRL LIDAR and MMCR RADAR data. The results of the retrieval method were used to successfully extract COD up to values of 3 and to separate TICs into two types : TIC1 characterized by small crystals (Deff < 30 mum) and TIC2 by large ice crystals (Deff > 30 mum, up to 300 mum). Inversions were performed across two polar winters. At the end of this research, we proposed different alternatives to apply our methodology in the Arctic. Keywords : Remote sensing ; ice clouds ; thermal infrared multi-band radiometry ; Arctic.

  6. Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of brown fat metabolism

    PubMed Central

    Rodrigues, Dario B.; Maccarini, Paolo F.; Salahi, Sara; Colebeck, Erin; Topsakal, Erdem; Pereira, Pedro J. S.; Limão-Vieira, Paulo; Stauffer, Paul R.

    2013-01-01

    Background Brown adipose tissue (BAT) plays an important role in whole body metabolism and could potentially mediate weight gain and insulin sensitivity. Although some imaging techniques allow BAT detection, there are currently no viable methods for continuous acquisition of BAT energy expenditure. We present a non-invasive technique for long term monitoring of BAT metabolism using microwave radiometry. Methods A multilayer 3D computational model was created in HFSS™ with 1.5 mm skin, 3–10 mm subcutaneous fat, 200 mm muscle and a BAT region (2–6 cm3) located between fat and muscle. Based on this model, a log-spiral antenna was designed and optimized to maximize reception of thermal emissions from the target (BAT). The power absorption patterns calculated in HFSS™ were combined with simulated thermal distributions computed in COMSOL® to predict radiometric signal measured from an ultra-low-noise microwave radiometer. The power received by the antenna was characterized as a function of different levels of BAT metabolism under cold and noradrenergic stimulation. Results The optimized frequency band was 1.5–2.2 GHz, with averaged antenna efficiency of 19%. The simulated power received by the radiometric antenna increased 2–9 mdBm (noradrenergic stimulus) and 4–15 mdBm (cold stimulus) corresponding to increased 15-fold BAT metabolism. Conclusions Results demonstrated the ability to detect thermal radiation from small volumes (2–6 cm3) of BAT located up to 12 mm deep and to monitor small changes (0.5 °C) in BAT metabolism. As such, the developed miniature radiometric antenna sensor appears suitable for non-invasive long term monitoring of BAT metabolism. PMID:24244831

  7. Microwave Radiometry of Snow-Covered Grasslands for the Estimation of Land-Atmosphere Energy and Moisture Fluxes

    NASA Astrophysics Data System (ADS)

    Galantowicz, John Francis

    1995-01-01

    This thesis presents a snowpack model and experimental data that link land-atmosphere interactions and microwave emission from snow-covered terrain. Energy and moisture fluxes between terrain and atmosphere are the boundary conditions for atmospheric dynamics and composition. As both computer capabilities and the understanding of land -atmosphere interactions improve, numerical models of weather and climate are using more sophisticated soil-vegetation -atmosphere transfer (SVAT) models as boundary conditions. The goal of this research is the use of space-based microwave radiometry to verify atmosphere-SVAT model dynamics. Original results from a seven month study of terrain radiobrightness in the northern Great Plains are presented. The data include: (a) continuous ground-based observations of terrain radiobrightness at a site near Sioux Falls, South Dakota, (b) micrometeorological observations at the same site, and (c) coincident antenna temperature measurements from the Special Sensor Microwave/Imager, a space-borne radiometer. The micrometeorological data drive a SVAT model that generates a 60 day snowpack simulation including moisture and energy flux estimates. The simulated snowpack in turn drives a simulation of snowpack radiobrightness. Comparisons are made between radiometric measurements from the ground-based and space-borne instruments, and between SVAT-linked predicted brightnesses and the measurements. The conclusions are that ground-based observations of terrain radiobrightness can simulate space-based observations when the field-of-view of the space-borne instrument is homogeneous; that a SVAT-linked emission model for snowpack radiobrightness simulations is feasible; and that radiobrightness predictions from such a model can be compared with radiometric measurements to improve the land-atmosphere transfer elements of the combined model.

  8. Accurate determination of electronic transport properties of silicon wafers by nonlinear photocarrier radiometry with multiple pump beam sizes

    SciTech Connect

    Wang, Qian; Li, Bincheng

    2015-12-07

    In this paper, photocarrier radiometry (PCR) technique with multiple pump beam sizes is employed to determine simultaneously the electronic transport parameters (the carrier lifetime, the carrier diffusion coefficient, and the front surface recombination velocity) of silicon wafers. By employing the multiple pump beam sizes, the influence of instrumental frequency response on the multi-parameter estimation is totally eliminated. A nonlinear PCR model is developed to interpret the PCR signal. Theoretical simulations are performed to investigate the uncertainties of the estimated parameter values by investigating the dependence of a mean square variance on the corresponding transport parameters and compared to that obtained by the conventional frequency-scan method, in which only the frequency dependences of the PCR amplitude and phase are recorded at single pump beam size. Simulation results show that the proposed multiple-pump-beam-size method can improve significantly the accuracy of the determination of the electronic transport parameters. Comparative experiments with a p-type silicon wafer with resistivity 0.1–0.2 Ω·cm are performed, and the electronic transport properties are determined simultaneously. The estimated uncertainties of the carrier lifetime, diffusion coefficient, and front surface recombination velocity are approximately ±10.7%, ±8.6%, and ±35.4% by the proposed multiple-pump-beam-size method, which is much improved than ±15.9%, ±29.1%, and >±50% by the conventional frequency-scan method. The transport parameters determined by the proposed multiple-pump-beam-size PCR method are in good agreement with that obtained by a steady-state PCR imaging technique.

  9. Kinetic buffers.

    PubMed

    Alibrandi, Giuseppe; Fabbrizzi, Luigi; Licchelli, Maurizio; Puglisi, Antonio

    2015-01-12

    This paper proposes a new type of molecular device that is able to act as an inverse proton sponge to slowly decrease the pH inside a reaction vessel. This makes the automatic monitoring of the concentration of pH-sensitive systems possible. The device is a composite formed of an alkyl chloride, which kinetically produces acidity, and a buffer that thermodynamically modulates the variation in pH value. Profiles of pH versus time (pH-t plots) have been generated under various experimental conditions by computer simulation, and the device has been tested by carrying out automatic spectrophotometric titrations, without using an autoburette. To underline the wide variety of possible applications, this new system has been used to realize and monitor HCl uptake by a di-copper(II) bistren complex in a single run, in a completely automatic experiment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The variability of nonmigrating tides detected from TIMED/SABER observations

    NASA Astrophysics Data System (ADS)

    Li, Xing; Wan, Weixing; Ren, Zhipeng; Liu, Libo; Ning, Baiqi

    2015-12-01

    This paper deals with the variability of the nonmigrating tides detected from the observation of the SABER instrument on board the TIMED satellite during the 11 year solar period from 2002 to 2012. The longitudinal wave number spectra with 1 day resolution were first estimated from the temperature data measured at the MLT altitudes (70-110 km) and at the lower midlatitudes and low latitudes (between ±45°). Then we used the wave number 4 component to obtain the nonmigrating tides in which the dominant component DE3 was further analyzed in detail. We found that the properties of the spatial distribution and large time scale variation of the DE3 component are similar to those of the previous works, which used the interpolated data with 2 month resolution. These properties are that the DE3 component occurs mainly at the low latitudes within ±30° and at the altitudes from 90 to 110 km; the tidal amplitude is larger during boreal summer and early autumn, smaller in spring and almost tends to disappear in winter; the component is slightly stronger during the eastward wind QBO phase than the westward phase. Practically, the higher-resolution data were used to reveal the day-to-day variability of the DE3 component. It is found that (1) the variability occurs mainly at the altitudes from 100 to 110 km with a peak at 106 km; (2) it is strong at the low latitudes and peaks around the equator, as well, slightly stronger in the Southern Hemisphere than in northern one; (3) it is considerably larger around solstitial months than equinoctial months; and (4) it would not experience an obvious interannual variation. The day-to-day variability of the DE3 component may be explained by the variance of the absolute amplitudes and the contribution of the wave phases, and the later seems to play more important role.

  11. Ray-tracing simulation and SABER satellite observations of convective gravity waves

    NASA Astrophysics Data System (ADS)

    Kalisch, Silvio; Eckermann, Stephen; Ern, Manfred; Preusse, Peter; Riese, Martin; Trinh, Quang Thai; Kim, Young-Ha; Chun, Hye-Yeong

    Gravity waves (GWs) are known as a coupling mechanism between different atmospheric layers. They contribute to the wave-driving of the QBO and are also responsible for driving large scale circulations like the Brewer-Dobson circulation. One major and highly variable source of GWs is convection. Deep convection in the tropics excites GWs with prominent amplitudes and horizontal phase speeds of up to 90 m/s. These GWs propagate upward and, when breaking, release the wave's momentum, thus accelerate the background flow. Direction and magnitude of the acceleration strongly depends on wind filtering between the convective GW source and the considered altitude. Both, the generation mechanism of GWs close to the top of deep convective towers and the wind filtering process during GW propagation largely influence the GW spectrum found in the tropical middle atmosphere and therefore magnitude and direction of the acceleration. We present the results of GW ray-tracing calculations from tropospheric (convective) sources up to the mesosphere. The Gravity wave Regional Or Global RAy-Tracer (GROGRAT) was used to perform the GW trajectory calculations. The convective GW source scheme from Yonsei University (South Korea) served as the lower boundary condition to quantify the GW excitation from convection. Heating rates, cloud top data, and atmospheric background data were provided by the MERRA dataset for the calculation of convective forcing from deep convection and for the atmospheric background of the ray-tracing calculations afterwards. In order to validate our ray-tracing simulation results, we compare them to satellite measurements of temperature amplitudes and momentum fluxes from the SABER instrument. Therefore, observational constrains from limb-sounding instruments have been quantified. Influences of orbit geometry, the instrument's observational filter, and the wavelength shift in the observed GW spectrum are discussed. Geographic structures in the observed global

  12. The Radiative Lifetime of O2(1Delta) From Sunset SABER Measurements

    NASA Astrophysics Data System (ADS)

    Nair, H.

    2008-12-01

    Electronically excited O2(1Δ) is produced during the day from photolysis of ozone. Its emission at 1.27 μm has long been used to infer ozone abundances during the day. The 1.27 μm emission is also seen at night. A better understanding of the chemistry of O2(1Δ) at night will be valuable in inferring the abundance of atomic oxygen, as O is thought to play a key role. The only significant loss processes of O2(1Δ) in the mesosphere are collisional quenching with O2 and O, and radiative decay. Quenching by O2 dominates at 70 km, radiative decay dominates at 80 km, and quenching by O dominates at 90 km. An accurate estimate of the radiative decay rate is important for the retrievals of O and O3. However, currently reported Einstein A coefficients for radiative decay at 1.27 μm from laboratory and atmospheric emission studies have ranged from 1.47×10-4s-1 (corresponding to a lifetime of 6800 s) to 2.58×10-4 s-1 (3900 s). Using SABER observations of the decay of the 1.27 micron O2(1Δ) airglow after sunset in the 70 to 90 km altitude region, we can derive a radiative lifetime that best fits the data. Initial estimates of the decay lifetime are consistent with the most recent laboratory value of 4500 s measured by Lafferty et al. (1998) and Spalek et al. (1999). REFERENCES: Lafferty, W.J., A.M. Solodov, C.L. Lugez, and G.T. Fraser, Applied Optics, 37(12), 2264-2270 (1998) Špalek, O., J. Kodymová, P. Stopka, and I. Miček, J. Phys. B: At. Mol. Opt. Phys., 32, 1885-1892 (1999)

  13. The variability of nonmigrating tides detected from TIMED/SABER observations

    NASA Astrophysics Data System (ADS)

    Li, Xing; Liu, Libo; Ning, Baiqi; Ren, Zhipeng; Wan, Weixing

    2016-07-01

    This work deals with the variability of the nonmigrating tides detected from the observation of the SABER instrument on board the TIMED satellite during the 11 year solar period from 2002 to 2012. The longitudinal wave number spectra with 1 day resolution were first estimated from the temperature data measured at the MLT altitudes (70-110 km) and at the lower midlatitudes and low latitudes (between ±±45°°). Then we used the wave number 4 component to obtain the nonmigrating tides in which the dominant component DE3 was further analyzed in detail. We found that the properties of the spatial distribution and large time scale variation of the DE3 component are similar to those of the previous works, which used the interpolated data with 2 month resolution. These properties are that the DE3 component occurs mainly at the low latitudes within ±30° and at the altitudes from 90 to 110 km; the tidal amplitude is larger during boreal summer and early autumn, smaller in spring and almost tends to disappear in winter; the component is slightly stronger during the eastward wind QBO phase than the westward phase. Practically, the higher-resolution data were used to reveal the day-to-day variability of the DE3 component. It is found that (1) the variability occurs mainly at the altitudes from 100 to 110 km with a peak at 106 km; (2) it is strong at the low latitudes and peaks around the equator, as well, slightly stronger in the Southern Hemisphere than in northern one; (3) it is considerably larger around solstitial months than equinoctial months; and (4) it would not experience an obvious interannual variation. The day-to-day variability of the DE3 component may be explained by the variance of the absolute amplitudes and the contribution of the wave phases, and the later seems to play more important role.

  14. Implications of Diet for the Extinction of Saber-Toothed Cats and American Lions

    PubMed Central

    DeSantis, Larisa R. G.; Schubert, Blaine W.; Scott, Jessica R.; Ungar, Peter S.

    2012-01-01

    The saber-toothed cat, Smilodon fatalis, and American lion, Panthera atrox, were among the largest terrestrial carnivores that lived during the Pleistocene, going extinct along with other megafauna ∼12,000 years ago. Previous work suggests that times were difficult at La Brea (California) during the late Pleistocene, as nearly all carnivores have greater incidences of tooth breakage (used to infer greater carcass utilization) compared to today. As Dental Microwear Texture Analysis (DMTA) can differentiate between levels of bone consumption in extant carnivores, we use DMTA to clarify the dietary niches of extinct carnivorans from La Brea. Specifically, we test the hypothesis that times were tough at La Brea with carnivorous taxa utilizing more of the carcasses. Our results show no evidence of bone crushing by P. atrox, with DMTA attributes most similar to the extant cheetah, Acinonyx jubatus, which actively avoids bone. In contrast, S. fatalis has DMTA attributes most similar to the African lion Panthera leo, implying that S. fatalis did not avoid bone to the extent previously suggested by SEM microwear data. DMTA characters most indicative of bone consumption (i.e., complexity and textural fill volume) suggest that carcass utilization by the extinct carnivorans was not necessarily more complete during the Pleistocene at La Brea; thus, times may not have been “tougher” than the present. Additionally, minor to no significant differences in DMTA attributes from older (∼30–35 Ka) to younger (∼11.5 Ka) deposits offer little evidence that declining prey resources were a primary cause of extinction for these large cats. PMID:23300674

  15. Implications of diet for the extinction of saber-toothed cats and American lions.

    PubMed

    Desantis, Larisa R G; Schubert, Blaine W; Scott, Jessica R; Ungar, Peter S

    2012-01-01

    The saber-toothed cat, Smilodon fatalis, and American lion, Panthera atrox, were among the largest terrestrial carnivores that lived during the Pleistocene, going extinct along with other megafauna ∼12,000 years ago. Previous work suggests that times were difficult at La Brea (California) during the late Pleistocene, as nearly all carnivores have greater incidences of tooth breakage (used to infer greater carcass utilization) compared to today. As Dental Microwear Texture Analysis (DMTA) can differentiate between levels of bone consumption in extant carnivores, we use DMTA to clarify the dietary niches of extinct carnivorans from La Brea. Specifically, we test the hypothesis that times were tough at La Brea with carnivorous taxa utilizing more of the carcasses. Our results show no evidence of bone crushing by P. atrox, with DMTA attributes most similar to the extant cheetah, Acinonyx jubatus, which actively avoids bone. In contrast, S. fatalis has DMTA attributes most similar to the African lion Panthera leo, implying that S. fatalis did not avoid bone to the extent previously suggested by SEM microwear data. DMTA characters most indicative of bone consumption (i.e., complexity and textural fill volume) suggest that carcass utilization by the extinct carnivorans was not necessarily more complete during the Pleistocene at La Brea; thus, times may not have been "tougher" than the present. Additionally, minor to no significant differences in DMTA attributes from older (∼30-35 Ka) to younger (∼11.5 Ka) deposits offer little evidence that declining prey resources were a primary cause of extinction for these large cats.

  16. Seasonal and QBO variations in the OH nightglow emission observed by TIMED/SABER

    NASA Astrophysics Data System (ADS)

    Gao, Hong; Xu, Jiyao; Wu, Qian

    2010-06-01

    Using TIMED/SABER observations, we present global distribution of the semiannual oscillation (SAO), annual oscillation (AO), and quasi-biennial oscillation (QBO) in the OH nightglow peak emission rate and height as well as the intensity. The latitudinal variations of the SAO, AO, and QBO in the peak emission rate are similar to those in the intensity. For the peak emission rate and the intensity, the SAO and QBO amplitudes have three peaks (one at the equator and others at about 35°S and 35°N). The AO amplitude peaks at about 20°S and 20°N, respectively. The SAO phase is delayed poleward from the equinoxes at the equator to the solstices at 50°S/N in addition, the phases of the AO are delayed poleward from 30°S. For the peak height, the SAO and QBO amplitudes have three peaks (around the equator, 40°S, and 40°N). Its AO amplitudes at 50°S and 50°N are larger than those at other latitudes; the phase of the SAO shifts from the solstice at the equator to near the equinoxes at 50°S/N. The airglow QBO is stronger in tropics than midlatitude and is likely the real QBO oscillation at the equator. In addition, the emission in the Southern Hemisphere is weaker than that in the Northern Hemisphere. The SAO and QBO are hemispherically symmetrical, and the AO is hemispherically antisymmetrical at some latitudes. The peak emission rate and peak height SAOs are generally in antiphase. The peak emission rate and intensity SAOs are generally in phase.

  17. Update on the Standoff Detection of Radiological Materials by Passive FTIR Radiometry. 2006-2007 Summary Report for the Canadian Safeguards Support Program of the Canadian Nuclear Safety Commission

    DTIC Science & Technology

    2007-06-01

    FTIR radiometry for detecting and identifying UO2 and U3O8 radioactive materials at standoff distances of 30 and 100 m. This would be the first time...collaboration with Cameco Corp., several uranium oxide materials (including processed and non-processed uranium ores) and waste materials from the

  18. CO2(ν2)-O Quenching Rate Coefficient Derived From Coincidental Fort Collins Lidar and SABER Measurements

    NASA Astrophysics Data System (ADS)

    Feofilov, A.; Kutepov, A.; She, C.; Smith, A. K.; Pesnell, W. D.; Goldberg, R. A.

    2009-12-01

    Among the processes governing the energy balance in the mesosphere and lower thermosphere (MLT), the quenching of CO2(ν2) vibrational levels in collisions with oxygen atoms plays an important role. However, neither the rate coefficient of this process (k(CO2-O)) nor the atomic oxygen concentrations ([O]) in the MLT are well known. The discrepancy between k(CO2-O) measured in the lab and retrieved from atmospheric measurements is of about factor of 2.5. At the same time, the discrepancy between [O] in the MLT measured by different instruments is of the same order of magnitude. In this work we combine temperature data from a ground based lidar with limb radiances from a satellite infrared radiometer to estimate k(CO2-O). We used the night- and daytime temperatures between 80 and 110 km measured by the Colorado State University narrow-band sodium (Na) lidar located at Fort Collins, Colorado (41N, 255E) as ground truth of the SABER/TIMED nearly simultaneous (±10 minutes ) and common volume (within ±1 degree in latitude, ±2 degrees in longitude) observations. We used ALI-ARMS non-LTE research code designed to calculate the non-equilibrium radiance in planetary atmospheres to retrieve the product of k(CO2-O) x [O] from 15 μm CO2 limb radiance measured by SABER. The values retrieved for all overlapping measurements were then used to estimate the k(CO2-O) rate coefficient and its possible variation range by utilizing the [O] values measured by the SABER and other instruments.

  19. Uncertainty of Passive Imager Cloud Optical Property Retrievals to Instrument Radiometry and Model Assumptions: Examples from MODIS

    NASA Technical Reports Server (NTRS)

    Platnick, Steven; Wind, Galina; Meyer, Kerry; Amarasinghe, Nandana; Arnold, G. Thomas; Zhang, Zhibo; King, Michael D.

    2013-01-01

    The optical and microphysical structure of clouds is of fundamental importance for understanding a variety of cloud radiation and precipitation processes. With the advent of MODIS on the NASA EOS Terra and Aqua platforms, simultaneous global-daily 1 km retrievals of cloud optical thickness (COT) and effective particle radius (CER) are provided, as well as the derived water path (WP). The cloud product (MOD06/MYD06 for MODIS Terra and Aqua, respectively) provides separate retrieval datasets for various two-channel retrievals, typically a VISNIR channel paired with a 1.6, 2.1, and 3.7 m spectral channel. The MOD06 forward model is derived from on a homogeneous plane-parallel cloud. In Collection 5 processing (completed in 2007 with a modified Collection 5.1 completed in 2010), pixel-level retrieval uncertainties were calculated for the following non-3-D error sources: radiometry, surface spectral albedo, and atmospheric corrections associated with model analysis uncertainties (water vapor only). The latter error source includes error correlation across the retrieval spectral channels. Estimates of uncertainty in 1 aggregated (Level-3) means were also provided assuming unity correlation between error sources for all pixels in a grid for a single day, and zero correlation of error sources from one day to the next. I n Collection 6 (expected to begin in late summer 2013) we expanded the uncertainty analysis to include: (a) scene-dependent calibration uncertainty that depends on new band and detector-specific Level 1B uncertainties, (b) new model error sources derived from the look-up tables which includes sensitivities associated with wind direction over the ocean and uncertainties in liquid water and ice effective variance, (c) thermal emission uncertainties in the 3.7 m band associated with cloud and surface temperatures that are needed to extract reflected solar radiation from the total radiance signal, (d) uncertainty in the solar spectral irradiance at 3.7 m, and

  20. The variability of SE2 tide extracted from TIMED/SABER observations

    NASA Astrophysics Data System (ADS)

    Li, Xing; Wan, Weixing; Ren, Zhipeng; Yu, You

    2017-04-01

    Based on the temperature observations of the SABER/TIMED, the variability of the non-migrating tide SE2 with high resolution (one-day) is analyzed, using the method from Li et al., [2015]. From the temperature observation data measured in the mesosphere and lower atmosphere region (MLT, 70-110 km altitudes) and at the low- and mid -latitudes (45S - 45N) from2002 to 2012), we obtained the non-migrating tide SE2 and further studied it in detail. It is found that the climatological features (large time scale variability and spatial distribution) of the SE2 tidal component are similar with the results from the previous researches, which are picked up from the interpolated data with 60-day resolution. The climatological features are that the SE2 tidal component manifests mainly at the low-mid latitudes around 30. The northern hemisphere tidal amplitudes below 110 km are larger than the southern hemisphere tide, at the same time, its peaks below 110 km mainly present between 100 and 110 km altitude; the tidal amplitudes below 110 km occur a north-south asymmetry about the equator in the annual variation: in the southern hemisphere, SE2 occurs with an obvious annual variation with a maximum of tidal amplitudes in December; while, in the northern one, the semi-annual variations with maximum at the equinoxes are stronger than that in the southern one. Herein, owing to the high-resolution tidal data (one day), we could research the short term (day-to-day) variations of the SE2 tide. We found that: (1) the day-to-day variations manifests mainly at the altitudes range between 100 and 110 km; (2) it increases gradually with latitudes and it is stronger at the low-mid latitudes; (3) it is relatively slightly stronger around solstices than equinoxes; (4) it does not present a remarkably inter-annual variation. Finally, the SE2 day-to-day variations may be composed by the absolute amplitudes' variance and the impact of the wave phases. In addition, the variations of

  1. First evidence of pathology in the forelimb of the late Miocene saber-toothed felid Promegantereon ogygia (Machairodontinae, Smilodontini).

    PubMed

    Salesa, Manuel J; Antón, Mauricio; Siliceo, Gema; Pesquero, María Dolores; Alcalá, Luis

    2014-06-01

    We examined the first evidence of pathology in the forelimb of the primitive saber-toothed felid Promegantereon ogygia, observed in a radius from the late Miocene (Vallesian, MN 10) site of La Roma 2 (Teruel, Spain). This fossil is the first evidence of a member of the Machairodontinae in this locality, and the first fossil of this species found in the Miocene basin of Teruel. The radius shows an exostosis shaped as a rough and wide bony crest probably caused by the lesion and posterior ossification of part of the tendon of the muscle abductor pollicis longus, an important extensor and abductor of the thumb. The lesion was probably due to a tearing or to high levels of exertion experienced by this muscle over a relatively long time, a general type of lesion also observed in other vertebrate fossils. With saber-toothed felids using their thumbs to immobilize prey during the hunt, the studied lesion probably affected in a significant manner the predatory abilities of the animal, causing at least a decrease in its hunting success rate.

  2. C02(nu2)-0 Quenching Rate Coefficient Derived from Coincidental Fort Collins Lidar and SABER Measurements

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Kutepov, A. A.; She, C. Y.; Smith, A. K.; Pesnell, W. D.; Goldberg, R. A.

    2009-01-01

    Among the processes governing the energy balance in the mesosphere and lower thermosphere (MLT), the quenching of CO2(V2) vibrational levels in collisions with oxygen atoms plays an important role. However, neither the rate coefficient of this process (k(CO2O)) nor the atomic oxygen concentrations ([O]) in the MLT are well known. The discrepancy between k(CO2O) measured in the lab and retrieved from atmospheric measurements is of about factor of 2.5. At the same time, the discrepancy between [O] in the MLT measured by different instruments is of the same order of magnitude. In this work we used a synergy of a ground based lidar and satellite infrared radiometer to make a further step in understanding of the physics of the region. In this study we apply the night- and daytime temperatures between 80 and 110 km measured by the Colorado State University narrow-band sodium (Na) lidar located at Fort Collins, Colorado for retrieving the product of k(CO2-O) x [O] from the limb radiances in the 15 micron channel measured by the SABER/TIMED instrument for nearly simultaneous common volume measurements of both instruments within +/-1 degree in latitude, +/-2 degrees in longitude and +/-10 minutes in time. We derive k(CO2-O) and its possible variation range from the retrieved product by utilizing the [O] values measured by the SABER and other instruments.

  3. Inter-Hemispheric Coupling During Northern Polar Summer Periods of 2002-2010 using TIMED/SABER Measurements

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Feofilov, A. G.; Pesnell, W. D.; Kutepov, A. A.

    2012-01-01

    It has been found that for more than one polar summer season between 2002-2010, the northern polar mesospheric region near and above about 80 km was warmer than normal. The strongest warming effect of this type was observed to occur during northern summer 2002. Theoretical studies have implied that these "anomalies" were preceded by unusual dynamical processes in the southern hemisphere. We have analyzed temperature distributions measured by the SABER limb scanning infrared radiometer aboard the NASA TIMED satellite between 2002-2010 at altitudes from 15 to 110 km and for latitudes between 83 S to 83 N. We describe the approach to trace the inter-hemispheric temperature correlations demonstrating the global features that were unique for the "anomalous" northern polar summers. From our analysis of SABER data from 2002-2010, the anomalous heating for the northern mesopause region during northern summer was accompanied by stratospheric heating in the equatorial region. In the winter hemisphere it is accompanied by heating in the lower stratosphere and mesopause region, and cooling in the stratopause region. Also, all the elements of the temperature anomaly structure appear to develop and fade away nearly simultaneously, thereby suggesting either a global influence or a rapid exchange.

  4. Storm/Quiet Ratio Comparisons Between TIMED/SABER NO (sup +)(v) Volume Emission Rates and Incoherent Scatter Radar Electron Densities at E-Region Altitudes

    NASA Technical Reports Server (NTRS)

    Fernandez, J. R.; Mertens, C. J.; Bilitza, D.; Xu, X.; Russell, J. M., III; Mlynczak, M. G.

    2009-01-01

    Broadband infrared limb emission at 4.3 microns is measured by the TIMED/SABER instrument. At night, these emission observations at E-region altitudes are used to derive the so called NO+(v) Volume Emission Rate (VER). NO+(v) VER can be derived by removing the background CO2(v3) 4.3 microns radiance contribution using SABER-based non-LTE radiation transfer models, and by performing a standard Abel inversion on the residual radiance. SABER observations show that NO+(v) VER is significantly enhanced during magnetic storms in accordance with increased ionization of the neutral atmosphere by auroral electron precipitation, followed by vibrational excitation of NO+ (i.e., NO+(v)) from fast exothermic ion-neutral reactions, and prompt infrared emission at 4.3 m. Due to charge neutrality, the NO+(v) VER enhancements are highly correlated with electron density enhancements, as observed for example by Incoherent Scatter Radar (ISR). In order to characterize the response of the storm-time E-region from both SABER and ISR measurements, a Storm/Quiet ratio (SQR) quantity is defined as a function of altitude. For SABER, the SQR is the ratio of the storm-to-quiet NO+(v) VER. SQR is the storm-to-quiet ratio of electron densities for ISR. In this work, we compare SABER and ISR SQR values between 100 to 120 km. Results indicate good agreement between these measurements. SQR values are intended to be used as a correction factor to be included in an empirical storm-time correction to the International Reference Ionosphere model at E-region altitudes.

  5. Determination of the carrier concentration in CdSe crystals from the effective infrared absorption coefficient measured by means of the photothermal infrared radiometry

    NASA Astrophysics Data System (ADS)

    Pawlak, M.

    2015-01-01

    In this paper, a non-contact method that allows to determine the carrier concentration in CdSe crystals is presented. The method relies on the measurement of the effective infrared absorption coefficient by means of the photothermal infrared radiometry (PTR). In order to obtain the effective infrared absorption coefficient and thermal diffusivity, the frequency characteristics of the PTR signal were analyzed in the frame of a one-dimensional heat transport model for infrared semitransparent crystals. The carrier concentrations were estimated using a theory introduced by Ruda and a recently proposed normalization procedure for the PTR signal. The deduced carrier concentrations of the investigated CdSe crystals are in reasonable agreement with those obtained using Hall measurements and infrared spectroscopy. The method presented in this paper can also be applied to other semiconductors with the carrier concentration in the range of 1014-1017 cm-3.

  6. Annual and inter-annual variations of 6.5-day-planetary-waves in MLT observed by TIMED/SABER

    NASA Astrophysics Data System (ADS)

    Huang, Yingying; Li, Huijun; Li, Chongyin; Zhang, Shaodong

    2017-04-01

    Annual and inter-annual variations of 6.5DWs in 20-110 km, 52°S-52°N, 2002-2016 are studied by using v2.0 TIMED/SABER kinetic temperature data. Firstly, global annual variations of 6.5DW's spectral power and amplitudes are obtained. Strong wave amplitudes emerge in 30°S/N-50°S/N, and peaks in altitude separate in stratosphere (40-50 km), mesosphere (80-90 km) and the lower thermosphere (100-110 km), respectively. Their annual variations are similar in both hemispheres, but different in altitude. In 40-50 km, the annual maximums emerge mostly in winters: Dec.-Jan. in the NH and Jul.-Aug. in the SH. In MLT, annual peaks arise twice in each half of year. In 80-90 km, they're mainly in equinoctial seasons and winters: May, Aug.-Sep. and Jan. in the NH and Feb., Nov. and May in the SH. In 100-110 km, they emerge mainly in equinoctial seasons: Apr.-May and Aug.-Sep. in the NH and Feb.-Mar. and Oct.-Nov. in the SH. Then, inter-annual variations of 6.5DW amplitudes during the 14-year period are studied. Frequency spectra of monthly-mean amplitudes show that, main dynamics in long-term variations of 6.5DWs are AO and SAO in both hemispheres. Besides, QBO are visible in both hemispheres and 4-month period signals are noticed in the NH in MLT. Amplitudes of SAO, AO and QBO are obtained by bandpass filter. Their amplitudes are comparable in stratosphere and mesosphere, and QBO signals are weaker than the others in the LT. Vertical variations both of SAO and AO amplitudes are very stable. AO structures have little inter-annual changes, while inter-annual variations of SAO are significant and are related with 6.5DW. It means that annual and inter-annual variations of 6.5DW are mainly controlled by AO and SAO, respectively. Although QBO signals are weaker and their variations are less regular than AO and SAO, their phases seems to relate with inter-annual variations of 6.5DW as well.

  7. Chemical and Biological Kinetics

    NASA Astrophysics Data System (ADS)

    Emanuel', N. M.

    1981-10-01

    Examples of the application of the methods and ideas of chemical kinetics in various branches of chemistry and biology are considered and the results of studies on the kinetics and mechanisms of autoxidation and inhibited and catalysed oxidation of organic substances in the liquid phase are surveyed. Problems of the kinetics of the ageing of polymers and the principles of their stabilisation are discussed and certain trends in biological kinetics (kinetics of tumour growth, kinetic criteria of the effectiveness of chemotherapy, problems of gerontology, etc.) are considered. The bibliography includes 281 references.

  8. Solar extinction radiometry

    NASA Technical Reports Server (NTRS)

    Goldman, A.

    1981-01-01

    Work on the spectral line parameters of hydroxyl radical band was completed. The UV-visible data obtained during 1977 balloon flights were used for zone quantification. The region between from 3100 A to 3500 A appears to be the best region to use for determining ozone columns with the three wavelength method. Ozone volume mixing ratios determined for the 1977 data were compared with standard middle latitude ozone profiles. Numerous high and low Sun scans were obtained during ascent and from float altitude (1981 balloon flight) at 0.003 A resolution in the 3068 A to 3089 A region. The spectra are being studied for OH identification and quantification.

  9. Radiometry in military applications

    NASA Astrophysics Data System (ADS)

    Chrzanowski, Krzysztof

    2001-08-01

    Missiles guided using optoelectronic methods, optoelectronic imaging systems (thermal imaging systems, night vision devices, LLLTV cameras, TV cameras), and optoelectronic countermeasures (smoke screens, camouflage paints and nets, IR flares, decoys, jamming systems, warning systems) are one of the most important components of modern military armament. There are numerous military standards, some of them secret, that precise radiometric parameters to be measured and the testing methods to be used. There is also much literature on the subject of testing of the systems mentioned above, although mostly on subject of testing of the thermal imaging systems. In spite of this apparently numerous literature, there still significant confusion in this area due to secrecy of some parameters and testing methods, differences in recommendations of different military standards, fast progress in military optoelectronics, and also due to enormous number of different types of optoelectronics systems used in the military armament. A review of testing methods of the three basic groups of optoelectronics systems used in modern military armament: the missiles guided using optoelectronics methods, the optoelectronic imaging systems, and the optoelectronic countermeasures is presented in this paper. Trends in the measuring sets.

  10. Radiometry using synchrotron radiation

    NASA Technical Reports Server (NTRS)

    Saloman, E. B.; Ebner, S. C.; Hughey, L. R.

    1981-01-01

    It is possible to use synchrotron radiation from electron synchrotrons and electron storage rings as an absolute source, especially in the VUV and soft X-ray regions where other standards are difficult to find. At the NBS, an electron storage ring (SURF-II) has been used to calibrate spectrometers and photometers utilized in solar and aeronomy research and in fusion plasma diagnostics. The radiation incident on these spectrometers can be calculated to uncertainties of 3%, and a technique to exactly determine the number of electrons orbiting in the ring is currently being developed to reduce this uncertainty. Detector calibrations between 5 and 55 nm are routinely performed at SURF-II and transfer standard detectors with 6-10% uncertainties over the range 5-254 nm are supplied.

  11. Radiometry of Deimos

    NASA Technical Reports Server (NTRS)

    Veeder, Glenn J.; Matson, Dennis L.; Tedesco, Edward F.; Lebofsky, Larry A.; Gradie, Jonathan C.

    1987-01-01

    Ground-based infrared photometry of Deimos at 4.8, 10, and 20 microns is reported. The observed fluxes are significantly brighter than predicted by the 'standard' thermal model. Recent recalibrations that modify the model beam pattern of the infrared emission are marginally consistent with the observations at 10 and 20, but not at 4.8 microns.

  12. Infrared Photothermal Radiometry.

    DTIC Science & Technology

    1984-04-10

    changes whenever the transmitted thermal wave crosses a void. This provides a means of nondestructive subsurface imaging of defects, and Busse found that...15 In the flash excitation, the excitation beam is modulated by a broad spectrum of Fourier modulation frequencies. In all cases of subsurface imaging , the...technique of Nordal and Kanstad 2 1t 23 is not only good for spectroscopic detection, but also for subsurface imaging applications as well. 2.4 Pulsed

  13. Cesium removal and kinetics equilibrium: Precipitation kinetics

    SciTech Connect

    Barnes, M.J.

    1999-12-17

    This task consisted of both non-radioactive and radioactive (tracer) tests examining the influence of potentially significant variables on cesium tetraphenylborate precipitation kinetics. The work investigated the time required to reach cesium decontamination and the conditions that affect the cesium precipitation kinetics.

  14. The Relationship of Safe and Participatory School Environments and Supportive Attitudes toward Violence: Evidence from the Colombian Saber Test of Citizenship Competencies

    ERIC Educational Resources Information Center

    Diazgranados, Silvia; Noonan, James

    2015-01-01

    In Colombia, reducing levels of interpersonal and community violence is a key component of the country's approach to citizenship education. In this study, we use data collected during the 2005 Saber test of Citizenship Competencies to examine the relationship of school environments and individual students' supportive attitudes toward violence…

  15. The Relationship of Safe and Participatory School Environments and Supportive Attitudes toward Violence: Evidence from the Colombian Saber Test of Citizenship Competencies

    ERIC Educational Resources Information Center

    Diazgranados, Silvia; Noonan, James

    2015-01-01

    In Colombia, reducing levels of interpersonal and community violence is a key component of the country's approach to citizenship education. In this study, we use data collected during the 2005 Saber test of Citizenship Competencies to examine the relationship of school environments and individual students' supportive attitudes toward violence…

  16. Tracing the Inter-Hemispheric Coupling During Polar Summer Periods of 2002-2010 Using TIMED/SABER Measurements

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard; Feoflow, Artem; Pesnell, Dean; Kutepov, Alexander

    2010-01-01

    It has been found that for more than one polar summer season between 2002-2010, the northern polar mesospheric region near and above the mesospheric maximum was warmer than normal. The strongest warming effect of this type was observed to occur during northern summer 2002. Theoretical studies have implied that these "anomalies" were preceded by unusual dynamical processes occurring in the southern hemisphere. We have analyzed temperature distributions measured by the SABER limb scanning infrared radiometer aboard the NASA TIMED satellite between 2002-2010 at altitudes from 15 to 110 km and for latitudes between 83 deg. S to 83 deg. N. We describe the approach to trace the inter-hemispheric temperature correlatoins and to identify the global features that were unique for the "anomalous" northern polar summers.

  17. Observations of infrared radiative cooling in the thermosphere on daily to multiyear timescales from the TIMED/SABER instrument (Invited)

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.

    2009-12-01

    We present observations of the infrared radiative cooling by carbon dioxide (CO2) and nitric oxide (NO) in Earth’s thermosphere. These data have been taken over a period of 7 years by the SABER instrument on the NASA TIMED satellite and are the dominant radiative cooling mechanisms for the thermosphere. From the SABER observations we derive vertical profiles of radiative cooling rates (W m-3), radiative fluxes (W m-2), and radiated power (W). In the period from January 2002 through January 2009 we observe a large decrease in the cooling rates, fluxes, and power consistent with the declining phase of solar cycle 23. The power radiated by NO during 2008 when the Sun exhibited few sunspots was nearly one order of magnitude smaller than the peak power observed shortly after the mission began. Substantial short-term variability in the infrared emissions is also observed throughout the entire mission duration. Radiative cooling rates and radiative fluxes from NO exhibit fundamentally different latitude dependence than do those from CO2, with the NO fluxes and cooling rates being largest at high latitudes and polar regions. The cooling rates are shown to be derived relatively independent of the collisional and radiative processes that drive the departure from local thermodynamic equilibrium (LTE) in the CO2 15 μm and the NO 5.3 μm vibration-rotation bands. The observed NO and CO2 cooling rates have been compiled into a separate dataset and represent a climate data record that is available for use in assessments of radiative cooling in upper atmosphere general circulation models.

  18. Observations of Infrared Radiative Cooling in the Thermosphere on Daily to Multiyear Timescales from the TIMED/SABER Instrument

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Hunt, Linda A.; Marshall, B. Thomas; Martin-Torres, F. Javier; Mertens, Christopher J.; Russell, James M., III; Remsberg, Ellis E.; Lopez-Puertas, Manuel; Picard, Richard; Winick, Jeremy; Wintersteiner, Peter; Thompson, R. Earl; Gordley, Larry L.

    2009-01-01

    We present observations of the infrared radiative cooling by carbon dioxide (CO2) and nitric oxide (NO) in Earth s thermosphere. These data have been taken over a period of 7 years by the SABER instrument on the NASA TIMED satellite and are the dominant radiative cooling mechanisms for the thermosphere. From the SABER observations we derive vertical profiles of radiative cooling rates (W/cu m), radiative fluxes (W/sq m), and radiated power (W). In the period from January 2002 through January 2009 we observe a large decrease in the cooling rates, fluxes, and power consistent with the declining phase of solar cycle. The power radiated by NO during 2008 when the Sun exhibited few sunspots was nearly one order of magnitude smaller than the peak power observed shortly after the mission began. Substantial short-term variability in the infrared emissions is also observed throughout the entire mission duration. Radiative cooling rates and radiative fluxes from NO exhibit fundamentally different latitude dependence than do those from CO2, with the NO fluxes and cooling rates being largest at high latitudes and polar regions. The cooling rates are shown to be derived relatively independent of the collisional and radiative processes that drive the departure from local thermodynamic equilibrium (LTE) in the CO2 15 m and the NO 5.3 m vibration-rotation bands. The observed NO and CO2 cooling rates have been compiled into a separate dataset and represent a climate data record that is available for use in assessments of radiative cooling in upper atmosphere general circulation models.

  19. Impacts of SABER CO2-based eddy diffusion coefficients in the lower thermosphere on the ionosphere/thermosphere

    NASA Astrophysics Data System (ADS)

    Salinas, Cornelius Csar Jude H.; Chang, Loren C.; Liang, Mao-Chang; Yue, Jia; Russell, James; Mlynczak, Martin

    2016-12-01

    This work estimates global-mean Kzz using Sounding of the Atmosphere using Broadband Emission Radiometry/Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics monthly global-mean CO2 profiles and a one-dimensional transport model. It is then specified as a lower boundary into the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). Results first show that global-mean CO2 in the mesosphere and lower thermosphere region has annual and semiannual oscillations (AO and SAO) with maxima during solstice seasons along with a primary maximum in boreal summer. Our calculated AO and SAO in global-mean CO2 are then modeled by AO and SAO in global-mean Kzz. It is then shown that our estimated global-mean Kzz is lower in magnitude than the suggested global-mean Kzz from Qian et al. (2009) that can model the observed AO and SAO in the ionosphere/thermosphere (IT) region. However, our estimated global-mean Kzz is similar in magnitude with recent suggestions of global-mean Kzz in models with explicit gravity wave parameterization. Our work therefore concludes that global-mean Kzz from global-mean CO2 profiles cannot model the observed AO and SAO in the IT region because our estimated global-mean Kzz may only be representing eddy diffusion due to gravity wave breaking. The difference between our estimated global-mean Kzz and the global-mean Kzz from Qian et al. (2009) thus represents diffusion and mixing from other nongravity wave sources not directly accounted for in the TIE-GCM lower boundary conditions. These other sources may well be the more dominant lower atmospheric forcing behind the AO and SAO in the IT region.

  20. Photocarrier radiometry for predicting the degradation of electrical parameters of monocrystalline silicon (c-Si) solar cell irradiated by 100 KeV proton beams

    NASA Astrophysics Data System (ADS)

    Song, P.; Liu, J. Y.; Yuan, H. M.; Oliullah, Md.; Wang, F.; Wang, Y.

    2016-09-01

    In this study, the monocrystalline silicon (c-Si) solar cell irradiated by 100 KeV proton beams at various fluences is investigated. A one-dimensional two-layer carrier density wave model has been developed to estimate the minority carrier lifetime of n-region and p-region of the non-irradiated c-Si solar cell by best fitting with the experimental photocarrier radiometry (PCR) signal (the amplitude and the phase). Furthermore, the lifetime is used to determine the initial defect density of the quasi-neutral region (QNR) of the solar cell to predict its I-V characteristics. The theoretically predicted short-circuit current density (Jsc), and open-circuit voltage (Voc) of the non-irradiated samples are in good agreement with experiment. Then a three-region defect distribution model for the c-Si solar cell irradiated by proton beams is carried out to describe the defect density distribution according to Monte Carlo simulation results and the initial defect density of the non-irradiated sample. Finally, we find that the electrical measurements of Jsc and Voc of the solar cells irradiated at different fluences using 100 KeV proton beams are consistent with the PCR predicting results.

  1. Variational Photocarrier Radiometry Reconstruction of Exciton Lifetime Spectra for a Coupled PbS Colloidal Quantum Dot Thin Film Under Combined AC and DC Laser Excitation

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Mandelis, Andreas; Melnikov, Alexander

    2015-06-01

    Colloidal quantum dots (CQDs) have attracted significant interest for applications in electronic and optoelectronic devices such as photodetectors, light emitting diodes, and solar cells. However, a poor understanding of charge transport in these nanocrystalline films hinders their practical applications. The photocarrier radiometry (PCR) technique, a frequency-domain photoluminescence method spectrally gated for radiative recombination photon emissions and exclusion of thermal infrared photons, has been applied to a coupled PbS CQD thin film with inter-dot spacing of 0.5 nm to 1 nm for the analysis of charge transport properties. As the nanoparticle bandgap depends on the size of the quantum dots, polydispersity of the CQD thin film causes bandgap variability leading to photoexcited carrier (exciton) decay lifetime broadening and temperature dependence. The carrier transport mechanisms of QDs are quite different from bulk semiconductors, so the conventional carrier-diffusion wave-based PCR theory was modified into a non-diffusive limit model. A developed variational discrete lifetime reconstruction approach was used to analyze PCR frequency scans under two optical excitation modes: a modulated laser source without, and with, an additional continuous laser source. Using this model, the CQD mean lifetime values were found and variational discrete lifetime spectra were reconstructed.

  2. Spectrally resolved modulated infrared radiometry of photothermal, photocarrier, and photoluminescence response of CdSe crystals: Determination of optical, thermal, and electronic transport parameters

    NASA Astrophysics Data System (ADS)

    Pawlak, M.; Chirtoc, M.; Horny, N.; Pelzl, J.

    2016-03-01

    Spectrally resolved modulated infrared radiometry (SR-MIRR) with super-band gap photoexcitation is introduced as a self-consistent method for semiconductor characterization (CdSe crystals grown under different conditions). Starting from a theoretical model combining the contributions of the photothermal (PT) and photocarrier (PC) signal components, an expression is derived for the thermal-to-plasma wave transition frequency ftc which is found to be wavelength-independent. The deviation of the PC component from the model at high frequency is quantitatively explained by a quasi-continuous distribution of carrier recombination lifetimes. The integral, broad frequency band (0.1 Hz-1 MHz) MIRR measurements simultaneously yielded the thermal diffusivity a, the effective IR optical absorption coefficient βeff, and the bulk carrier lifetime τc. Spectrally resolved frequency scans were conducted with interchangeable IR bandpass filters (2.2-11.3 μm) in front of the detector. The perfect spectral match of the PT and PC components is the direct experimental evidence of the key assumption in MIRR that de-exciting carriers are equivalent to blackbody (Planck) radiators. The exploitation of the β spectrum measured by MIRR allowed determining the background (equilibrium) free carrier concentration n0. At the shortest wavelength (3.3 μm), the photoluminescence (PL) component supersedes the PC one and has distinct features. The average sample temperature influences the PC component but not the PT one.

  3. Joint application of the satellite altimetry and radiometry data for the solution of a problem of ecological monitoring of a marine environment

    NASA Astrophysics Data System (ADS)

    Lebedev, S.

    Ecological monitoring of a marine environment of last years has shown, that alongside with processes of a destruction and deposition of pollutants not last role is played by dynamics of a marine surface, as the basic mass transfer. The models, existing on the present time, of calculation of currents usually use oceanographic and meteorological data obtained by the contact measurement methods. The apparent successes in development of ocean remote sensing methods open a path to creation of operating systems of ecological monitoring of a marine environment. The sea surface or dynamic topography calculated by satellite altimetry data, allows to analyze dynamics of the surface currents, which are not having brightly expressed thermal nature, as for instance, strong jet streams. In turn sea surface temperature, obtained by the satellite radiometry data, was used for more precise count of destruction processes of pollutants. Time-space scale of the satellite data from a ocean surface allow actively to use them in different models, that enables with a split-hair accuracy to make the physically reasonable forecast. Surface temperature and dynamic topography data sharing realized in the automated system "Regional Ecological Monitoring of a Marine Environment -- Black Sea", which basis by model of pollutant propagation. The research was undertaken with partial support from the Russian Basic Research Foundation (Project ? 01-07-90106).

  4. Joint Application of The Satellite Altimetry and Radiometry Data For Solution of A Problem of Ecological Monitoring of A Marine Environment

    NASA Astrophysics Data System (ADS)

    Lebedev, S. A.

    Ecological monitoring of a marine environment of last years has shown, that along- side with processes of a destruction and deposition of pollutants not last role is played by dynamics of a marine surface, as the basic mass transfer. The models, existing on the present time, of calculation of currents usually use oceanographic and meteoro- logical data obtained by the contact measurement methods. The apparent successes in development of ocean remote sensing methods open a path to creation of operating systems of ecological monitoring of a marine environment. The sea surface or dy- namic topography calculated by satellite altimetry data, allows to analyze dynamics of the surface currents, which are not having brightly expressed thermal nature, as for instance, strong jet streams. In turn sea surface temperature, obtained by the satellite radiometry data, was used for more precise count of destruction processes of pollu- tants. Time-space scale of the satellite data from a ocean surface allow actively to use them in different models, that enables with a split-hair accuracy to make the physically reasonable forecast. Surface temperature and dynamic topography data sharing real- ized in the automated system SRegional Ecological Monitoring of a Marine Environment U Black SeaT, which basis by model of pollutant propagation. The research was undertaken with partial support from the Russian Basic Research Foundation (Project #01-07-90106).

  5. Optoelectronic transport properties in amorphous/crystalline silicon solar cell heterojunctions measured by frequency-domain photocarrier radiometry: multi-parameter measurement reliability and precision studies.

    PubMed

    Zhang, Y; Melnikov, A; Mandelis, A; Halliop, B; Kherani, N P; Zhu, R

    2015-03-01

    A theoretical one-dimensional two-layer linear photocarrier radiometry (PCR) model including the presence of effective interface carrier traps was used to evaluate the transport parameters of p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) passivated by an intrinsic hydrogenated amorphous silicon (i-layer) nanolayer. Several crystalline Si heterojunction structures were examined to investigate the influence of the i-layer thickness and the doping concentration of the a-Si:H layer. The experimental data of a series of heterojunction structures with intrinsic thin layers were fitted to PCR theory to gain insight into the transport properties of these devices. The quantitative multi-parameter results were studied with regard to measurement reliability (uniqueness) and precision using two independent computational best-fit programs. The considerable influence on the transport properties of the entire structure of two key parameters that can limit the performance of amorphous thin film solar cells, namely, the doping concentration of the a-Si:H layer and the i-layer thickness was demonstrated. It was shown that PCR can be applied to the non-destructive characterization of a-Si:H/c-Si heterojunction solar cells yielding reliable measurements of the key parameters.

  6. Optoelectronic transport properties in amorphous/crystalline silicon solar cell heterojunctions measured by frequency-domain photocarrier radiometry: Multi-parameter measurement reliability and precision studies

    SciTech Connect

    Zhang, Y.; Melnikov, A.; Mandelis, A.; Halliop, B.; Kherani, N. P.; Zhu, R.

    2015-03-15

    A theoretical one-dimensional two-layer linear photocarrier radiometry (PCR) model including the presence of effective interface carrier traps was used to evaluate the transport parameters of p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) passivated by an intrinsic hydrogenated amorphous silicon (i-layer) nanolayer. Several crystalline Si heterojunction structures were examined to investigate the influence of the i-layer thickness and the doping concentration of the a-Si:H layer. The experimental data of a series of heterojunction structures with intrinsic thin layers were fitted to PCR theory to gain insight into the transport properties of these devices. The quantitative multi-parameter results were studied with regard to measurement reliability (uniqueness) and precision using two independent computational best-fit programs. The considerable influence on the transport properties of the entire structure of two key parameters that can limit the performance of amorphous thin film solar cells, namely, the doping concentration of the a-Si:H layer and the i-layer thickness was demonstrated. It was shown that PCR can be applied to the non-destructive characterization of a-Si:H/c-Si heterojunction solar cells yielding reliable measurements of the key parameters.

  7. Depth profile reconstructions of electronic transport properties in H{sup +} MeV-energy ion-implanted n-Si wafers using photocarrier radiometry

    SciTech Connect

    Tai, Rui; Wang, Chinhua Hu, Jingpei; Mandelis, Andreas

    2014-07-21

    A depth profiling technique using photocarrier radiometry (PCR) is demonstrated and used for the reconstruction of continuously varying electronic transport properties (carrier lifetime and electronic diffusivity) in the interim region between the ion residence layer and the bulk crystalline layer in H{sup +} implanted semiconductor wafers with high implantation energies (∼MeV). This defect-rich region, which is normally assumed to be part of the homogeneous “substrate” in all existing two- and three-layer models, was sliced into many virtual thin layers along the depth direction so that the continuously and monotonically variable electronic properties across its thickness can be considered uniform within each virtual layer. The depth profile reconstruction of both carrier life time and diffusivity in H{sup +} implanted wafers with several implantation doses (3 × 10{sup 14}, 3 × 10{sup 15}, and 3 × 10{sup 16} cm{sup −2}) and different implantation energies (from 0.75 to 2.0 MeV) is presented. This all-optical PCR method provides a fast non-destructive way of characterizing sub-surface process-induced electronic defect profiles in devices under fabrication at any intermediate stage before final metallization and possibly lead to process correction and optimization well before electrical testing and defect diagnosis becomes possible.

  8. Thermal conductivity of carbon doped GeTe thin films in amorphous and crystalline state measured by modulated photo thermal radiometry

    NASA Astrophysics Data System (ADS)

    Kusiak, Andrzej; Battaglia, Jean-Luc; Noé, Pierre; Sousa, Véronique; Fillot, F.

    2016-09-01

    The thermal conductivity and thermal boundary resistance of GeTe and carbon doped GeTe thin films, designed for phase change memory (PCM) applications, were investigated by modulated photo thermal radiometry. It was found that C doping has no significant effect on the thermal conductivity of these chalcogenides in amorphous state. The thermal boundary resistance between the amorphous films and SiO2 substrate is also not affected by C doping. The films were then crystallized by an annealing at 450°C as confirmed by optical reflectivity analysis. The thermal conductivity of non-doped GeTe significantly increases after crystallization annealing. But, surprisingly the thermal conductivity of the crystallized C doped GeTe was found to be similar from that of the amorphous state and independent of C concentration. As for the amorphous phase, C doping does not affect the thermal boundary resistance between the crystalline GeTe films and SiO2 substrate. This behaviour is discussed thanks to XRD and FTIR analysis. In particular, XRD shows a decrease of crystalline grain size in crystalline films as C concentration is increased. FTIR analysis of the film before and after crystallization evidenced that this evolution could be attributed to the disappearing of Ge-C bonds and migration of C atoms out of the GeTe phase upon crystallization, limiting then the growth of GeTe crystallites in C-doped films.

  9. Photocarrier Radiometry for Noncontact Evaluation of Monocrystalline Silicon (c-Si) Solar Cell Irradiated by 1 MeV Electron Beams

    NASA Astrophysics Data System (ADS)

    Song, P.; Liu, J. Y.; Yuan, H. M.; Wang, F.; Wang, Y.

    2016-08-01

    In this paper, the monocrystalline silicon (c-Si) solar cell irradiated by 1 MeV electron beams was investigated using noncontact photocarrier radiometry (PCR). A theoretical 1D two-layer PCR model including the impedance effect of the p-n junction was used to characterize the transport properties (carrier lifetime, diffusion coefficient, and surface recombination velocities) of c-Si solar cells irradiated by 1 MeV electron beams with different fluences. The carrier transport parameters were derived by the best fit through PCR measurements. Furthermore, an Ev+0.56 eV trap was introduced into the band gap based on the minority carrier lifetime reduction. An I-V characteristic was obtained by both AFORS-HET simulation and experimental study, and the simulation results shows in good agreement with the experimental results. Moreover, the simulation and experiment results also indicate that the increase of fluences of electron beams results in the reduction of short-circuit current and open-circuit voltage.

  10. Measurement of thermal properties of thin films up to high temperatures-Pulsed photothermal radiometry system and Si-B-C-N films

    NASA Astrophysics Data System (ADS)

    Martan, J.; Čapek, J.; Chalhoub, E. Amin

    2010-12-01

    A new arrangement of two-detector pulsed photothermal radiometry measurement system has been developed enabling temperature dependence measurement of thermal properties of thin films up to high temperatures. Only a few methods are available in this temperature range for thin films' thermal properties investigation, but there is a need for their knowledge in the fields of high-temperature electronics and high-speed machining. The present system enables simultaneous determination of the thin film effusivity, thermal conductivity, and volumetric specific heat in the temperature range from room temperature to 600 °C. The samples are placed in a vacuum chamber. The temperatures in the system were verified by an independent measurement and the system was tested on known bulk samples. Advantages and shortcomings of the method when used at higher temperatures and in the vacuum are described and discussed. Furthermore, Si-B-C-N thin films were studied. These amorphous ceramic materials possess an interesting set of mechanical and thermal properties. In particular, the films of the investigated chemical composition exhibit an excellent thermal stability at temperatures of up to 1700 °C. In the studied temperature range, from 20 to 600 °C, the thermal conductivity increased with increasing temperature from 1.72 to 1.89 W m-1 K-1 and volumetric specific heat increased from 2.65 to 3.76 × 106 J m-3 K-1.

  11. Influence of the Sampling Rate and Noise Characteristics on Prediction of the Maximal Safe Laser Exposure in Human Skin Using Pulsed Photothermal Radiometry

    NASA Astrophysics Data System (ADS)

    Vidovič, L.; Milanič, M.; Majaron, B.

    2013-09-01

    Pulsed photothermal radiometry (PPTR) allows for noninvasive determination of the laser-induced temperature depth profile in strongly scattering samples, including human skin. In a recent experimental study, we have demonstrated that such information can be used to derive rather accurate predictions of the maximal safe radiant exposure on an individual patient basis. This has important implications for efficacy and safety of several laser applications in dermatology and aesthetic surgery, which are often compromised by risk of adverse side effects (e.g., scarring, and dyspigmentation) resulting from nonselective absorption of strong laser light in epidermal melanin. In this study, the differences between the individual maximal safe radiant exposure values as predicted from PPTR temperature depth profiling performed using a commercial mid-IR thermal camera (as used to acquire the original patient data) and our customized PPTR setup are analyzed. To this end, the latter has been used to acquire 17 PPTR records from three healthy volunteers, using 1 ms laser irradiation at 532 nm and a signal sampling rate of 20 000 . The laser-induced temperature profiles are reconstructed first from the intact PPTR signals, and then by binning the data to imitate the lower sampling rate of the IR camera (1000 fps). Using either the initial temperature profile in a dedicated numerical model of heat transfer or protein denaturation dynamics, the predicted levels of epidermal thermal damage and the corresponding are compared. A similar analysis is performed also with regard to the differences between noise characteristics of the two PPTR setups.

  12. The saber microwave-powered helicopter project and related WPT research at the University of Alaska Fairbanks

    NASA Astrophysics Data System (ADS)

    Hawkins, Joe; Houston, Shawn; Hatfield, Michael; Brown, William

    1998-01-01

    This paper describes the current status of three projects at the University of Alaska Fairbanks with potential applications to Solar Power Satellites (SPS). The Semi-Autonomous BEam Rider (SABER) project is a model helicopter powered by a 1 horsepower electric motor and a rotor with a diameter of 1.15 m. It receives the power necessary to hover from a 1 kW microwave transmitter operating at 2.45 GHz. This project is intended to provide a test bed for development of Wireless Power Transmission (WPT) technology and an easily transportable demonstration of this technology. The power is received by an array of rectenna elements mounted beneath the helicopter. The ultimate goal is to integrate sensor and control subsystems onto the helicopter to measure the helicopter's attitude and position, and allow it to autonomously hover over the incident microwave beam. A second project consists of the continued refinement of a Magnetron Directional Amplifier (MDA) to provide an efficient, high power microwave source with independent control of phase and amplitude. Several MDA modules may be combined to provide an electronically-steerable phased array antenna in the future. A third project consists of computer simulations and optimization of sparse array antennas for SPS applications.

  13. Inter-Hemispheric Coupling During Recent North Polar Summer Periods as Predicted by MaCWAVE/MIDAS Rocket Data and Traced by TIMED/SABER Measurements

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Feofilov, Artem G.; Kutepov, Alexander A.; Pesnell, W. Dean; Schmidlin, Francis J.

    2011-01-01

    In July, 2002, the MaCWAVE-MIDAS Rocket Program was launched from And0ya Rocket Range (ARR) in Norway. Data from these flights demonstrated that the polar summer mesosphere during this period was unusual, at least above ARR. Theoretical studies have since been published that imply that the abnormal characteristics of this polar summer were generated by dynamical processes occurring in the southern polar winter hemisphere. We have used data from the SABER instrument aboard the NASA TIMED Satellite to study these characteristics and compare them with the features observed in the ensuing eight years. For background, the TIMED Satellite was launched on December 7, 2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The SABER instrument is a limb scanning infrared radiometer designed to measure temperature of the region as well as a large number of minor constituents. In this study, we review the MaCWAVE rocket results. Next, we investigate the temperature characteristics of the polar mesosphere as a function of spatial and temporal considerations. We have used the most recent SABER dataset (1.07). Weekly averages are used to make comparisons between the winter and summer hemispheres. Furthermore, the data analysis agrees with recent theoretical studies showing that this behavior is a result of anomalous dynamical events in the southern hemisphere. The findings discussed here clearly show the value of scientific rocket flights used in a discovery mode.

  14. Inter-Hemispheric Coupling During Recent North Polar Summer Periods as Predicted by MaCWAVE/MIDAS Rocket Data and Traced by TIMED/SABER Measurements

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Feofilov, Artem G.; Kutepov, Alexander A.; Pesnell W. Dean; Schmidlin, Francis J.

    2011-01-01

    In July, 2002, the MaCWAVE-MIDAS Rocket Program was launched from Andoya Rocket Range (ARR) in Norway. Data from these flights demonstrated that the polar summer mesosphere during this period was unusual, at least above ARR. Theoretical studies have since been published that imply that the abnormal characteristics of this polar summer were generated by dynamical processes occurring in the southern polar winter hemisphere. We have used data from the SABER instrument aboard the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) Satellite to study these characteristics and compare them with the features observed in the ensuing eight years. For background, the TIMED Satellite was launched on December 7,2001 to study the dynamics and energy of the mesosphere and lower thermosphere. The SABER instrument is a limb scanning infrared radiometer designed to measure temperature of the region as well as a large number of minor constituents. In this study, we review the MaCWAVE rocket results. Next, we investigate the temperature characteristics of the polar mesosphere as a function of spatial and temporal considerations. We have used the most recent SABER dataset (1.07). Weekly averages are used to make comparisons between the winter and summer hemispheres. Furthermore, the data analysis agrees with recent theoretical studies showing that this behavior is a result of anomalous dynamical events in the southern hemisphere. The findings discussed here clearly show the value of scientific rocket flights used in a discovery mode.

  15. The response of the temperature of cold-point mesopause to solar activity based on SABER data set

    NASA Astrophysics Data System (ADS)

    Tang, Chaoli; Liu, Dong; Wei, Heli; Wang, Yingjian; Dai, Congming; Wu, Pengfei; Zhu, Wenyue; Rao, Ruizhong

    2016-07-01

    The thermal structure and energy balance of upper atmosphere are dominated by solar activity. The response of cold-point mesopause (CPM) to solar activity is an important form. This article presents the response of the temperature of CPM (T-CPM) to solar activity using 14 year Sounding of the Atmosphere using Broadband Emission Radiometry data series over 80°S-80°N regions. These regions are divided into 16 latitude zones with 10° interval, and the spatial areas of 80°S-80°N, 180°W-180°E are divided into 96 lattices with 10°(latitude) × 60°(longitude) grid. The annual-mean values of T-CPM and F10.7 are calculated. The least squares regression method and correlation analysis are applied to these annual-mean series. First, the results show that the global T-CPM is significantly correlated to solar activity at the 0.05 level of significance with correlation coefficient of 0.90. The global solar response of T-CPM is 4.89 ± 0.67 K/100 solar flux unit. Then, for each latitude zone, the solar response of T-CPM and its fluctuation are obtained. The solar response of T-CPM becomes stronger with increasing latitude. The fluctuation ranges of solar response at middle-latitude regions are smaller than those of the equator and high-latitude regions, and the global distribution takes on W shape. The corelationship analysis shows that the T-CPM is significantly correlated to solar activity at the 0.05 level of significance for each latitude zone. The correlation coefficients at middle-latitude regions are higher than those of the equator and high-latitude regions, and the global distribution takes on M shape. At last, for each grid cell, the response of T-CPM to solar activity and their correlation coefficient are presented.

  16. A "Stationery" Kinetics Experiment.

    ERIC Educational Resources Information Center

    Hall, L.; Goberdhansingh, A.

    1988-01-01

    Describes a simple redox reaction that occurs between potassium permanganate and oxalic acid that can be used to prepare an interesting disappearing ink for demonstrating kinetics for introductory chemistry. Discusses laboratory procedures and factors that influence disappearance times. (CW)

  17. Chemical Kinetics Database

    National Institute of Standards and Technology Data Gateway

    SRD 17 NIST Chemical Kinetics Database (Web, free access)   The NIST Chemical Kinetics Database includes essentially all reported kinetics results for thermal gas-phase chemical reactions. The database is designed to be searched for kinetics data based on the specific reactants involved, for reactions resulting in specified products, for all the reactions of a particular species, or for various combinations of these. In addition, the bibliography can be searched by author name or combination of names. The database contains in excess of 38,000 separate reaction records for over 11,700 distinct reactant pairs. These data have been abstracted from over 12,000 papers with literature coverage through early 2000.

  18. Adequacy of kinetic models

    SciTech Connect

    Kiperman, S.L.

    1995-01-01

    The problems associated with the accuracy of kinetic models in heterogeneous catalysis and their adequacy to experimental data and reaction mechanisms are considered. The prospects for the further improvement and use of these models is also explored.

  19. A "Stationery" Kinetics Experiment.

    ERIC Educational Resources Information Center

    Hall, L.; Goberdhansingh, A.

    1988-01-01

    Describes a simple redox reaction that occurs between potassium permanganate and oxalic acid that can be used to prepare an interesting disappearing ink for demonstrating kinetics for introductory chemistry. Discusses laboratory procedures and factors that influence disappearance times. (CW)

  20. Thermal kinetic inductance detector

    DOEpatents

    Cecil, Thomas; Gades, Lisa; Miceli, Antonio; Quaranta, Orlando

    2016-12-20

    A microcalorimeter for radiation detection that uses superconducting kinetic inductance resonators as the thermometers. The detector is frequency-multiplexed which enables detector systems with a large number of pixels.

  1. Troposphere-Thermosphere Tidal Coupling as Measured by the SABER Instrument on TIMED during July-September, 2002

    NASA Technical Reports Server (NTRS)

    Forbes, J. M.; Russell, J.; Miyahara, S.; Zhang, X.; Palo, S.; Mlynczak, M.; Mertens, C. J.; Hagan, M. E.

    2005-01-01

    Coupling between the troposphere and lower thermosphere due to upward-propagating tides is investigated using temperatures measured from the SABER instrument on the TIMED satellite. The data analyzed here are confined to 20-120 km altitude and +/-40 deg latitude during 20 July 20 September, 2002. Apart from the migrating (sun-synchronous) tidal components, the predominant feature seen (from the satellite frame) during this period is a wave-4 structure in longitude with extrema of up to +/-40-50 K at 110 km. Amplitudes and longitudes of maxima of this structure evolve as the satellite precesses in local time, and as the wave(s) responsible for this structure vary with time. The primary wave responsible for the wave-4 pattern is the eastward-propagating diurnal tide with zonal wavenumber s=3 (DE3). Its average amplitude distribution over the interval is quasi-symmetric about the equator, similar to that of a Kelvin wave, with maximum of about 20 K at 5 deg S and 110 km. DE3 is primarily excited by latent heating due to deep tropical convection in the troposphere. It is demonstrated that existence of DE3 is intimately connected with the predominant wave-4 longitude distribution of topography and land-sea difference at low latitudes, and an analogy is drawn with the strong presence of DE1 in Mars atmosphere, the predominant wave-2 topography on Mars, and the wave-2 patterns that dominate density measurements from the Mars Global Surveyor (MGS) spacecraft near 130 km. Additional diurnal, semidiurnal and terdiurnal nonmigrating tides are also revealed in the present study. These tidal components are most likely excited by nonlinear interactions between their migrating counterparts and the stationary planetary wave with s=1 known to exist in the Southern Hemisphere during this period just prior to the austral mid-winter stratospheric warming of 2002.

  2. Fundamentals of enzyme kinetics.

    PubMed

    Seibert, Eleanore; Tracy, Timothy S

    2014-01-01

    This chapter provides a general introduction to the kinetics of enzyme-catalyzed reactions, with a focus on drug-metabolizing enzymes. A prerequisite to understanding enzyme kinetics is having a clear grasp of the meanings of "enzyme" and "catalysis." Catalysts are reagents that can increase the rate of a chemical reaction without being consumed in the reaction. Enzymes are proteins that form a subset of catalysts. These concepts are further explored below.

  3. Recent Advances in the Remote Sensing of Radiological Materials by Passive FTIR Radiometry. 2005-2006 Summary Report for the Canadian Safeguards Support Program of the Canadian Nuclear Safety Commission

    DTIC Science & Technology

    2006-05-01

    that some materials such as UO2 , UO3, U3O8 , CoO, Co2O3, ThO2, CsI, SrO, I2O5 and La2O3 have absorption features in the thermal infrared region, and...and strontium oxide (SrO). Initially it was planned to include two uranium oxides ( UO2 and U3O8 ); however, high wind conditions precluded their use...at DRDC Ottawa that will involve the use of ground-based passive standoff FTIR radiometry for detecting and identifying UO2 and U3O8 radioactive

  4. Airborne infrared video radiometry as a low-cost tool for remote sensing of the environment, two mapping examples from Israel of urban heat islands and mineralogical site

    SciTech Connect

    Ben-Dor, E.; Saaroni, H.; Ochana, D.

    1996-10-01

    In this study we examined the capability of a laboratory infrared video camera for use in remote sensing of the environment. The instrument used, INFRAMETRICS 760, was mounted onboard a Bell 206 helicopter. Under the flight conditions examined, the radiometer proved itself to be very stable and produced high-quality thermal images in a real-time mode. We studied two different environmental aspects, as follows: (1) Urban heat island of the most dense city in Israel, Tel-Aviv- and (2) lithological distribution of a well-known mineralogical site in Israel, Makhtesh Ramon. The radiometer used in both studies was able to produce a temperature presentation, rather than a gray scale from an altitude of 7,000 and 10,000 feet and at 70 knots air speed. The instrument produced a high-quality set of data in terms of signal-to-noise, stability, temperature accuracy and spatial resolution. In the Tel-Aviv case, the results showed that the urban heat island of the city can be depicted in a very high spatial and thermal resolutions domain and that a significant correlation exists between ground objects and the surrounding air temperature values. Based on the flight results, we could generated an isotherm map of the city that, for the first time, located the urban heat island of the city both in meso- and microscales. In the case of Makhtesh Ramon, we found that under field conditions, the radiometer, coupled with a VIS-CCD camera can provide significant ATI parameters of typical rocks that characterize tile study area. Although more study is planned and suggested based on the current data, it was concluded that the airborne thermal video radiometry, is a promising, inexpensive tool for monitoring the environment on a real-time basis. 10 refs., 5 figs., 1 tab.

  5. A sea-ice thickness retrieval model for 1.4 GHz radiometry and application to airborne measurements over low salinity sea-ice

    NASA Astrophysics Data System (ADS)

    Kaleschke, L.; Maaß, N.; Haas, C.; Hendricks, S.; Heygster, G.; Tonboe, R. T.

    2010-12-01

    In preparation for the European Space Agency's (ESA) Soil Moisture and Ocean Salinity (SMOS) mission, we investigated the potential of L-band (1.4 GHz) radiometry to measure sea-ice thickness. Sea-ice brightness temperature was measured at 1.4 GHz and ice thickness was measured along nearly coincident flight tracks during the SMOS Sea-Ice campaign in the Bay of Bothnia in March 2007. A research aircraft was equipped with the L-band Radiometer EMIRAD and coordinated with helicopter based electromagnetic induction (EM) ice thickness measurements. We developed a three layer (ocean-ice-atmosphere) dielectric slab model for the calculation of ice thickness from brightness temperature. The dielectric properties depend on the relative brine volume which is a function of the bulk ice salinity and temperature. The model calculations suggest a thickness sensitivity of up to 1.5 m for low-salinity (multi-year or brackish) sea-ice. For Arctic first year ice the modelled thickness sensitivity is less than half a meter. It reduces to a few centimeters for temperatures approaching the melting point. The campaign was conducted under unfavorable melting conditions and the spatial overlap between the L-band and EM-measurements was relatively small. Despite these disadvantageous conditions we demonstrate the possibility to measure the sea-ice thickness with the certain limitation up to 1.5 m. The ice thickness derived from SMOS measurements would be complementary to ESA's CryoSat-2 mission in terms of the error characteristics and the spatiotemporal coverage. The relative error for the SMOS ice thickness retrieval is expected to be not less than about 20%.

  6. Study of Exciton Hopping Transport in PbS Colloidal Quantum Dot Thin Films Using Frequency- and Temperature-Scanned Photocarrier Radiometry

    NASA Astrophysics Data System (ADS)

    Hu, Lilei; Mandelis, Andreas; Melnikov, Alexander; Lan, Xinzheng; Hoogland, Sjoerd; Sargent, Edward H.

    2017-01-01

    Solution-processed colloidal quantum dots (CQDs) are promising materials for realizing low-cost, large-area, and flexible photovoltaic devices. The study of charge carrier transport in quantum dot solids is essential for understanding energy conversion mechanisms. Recently, solution-processed two-layer oleic-acid-capped PbS CQD solar cells with one layer treated with tetrabutylammonium iodide (TBAI) serving as the main light-absorbing layer and the other treated with 1,2-ethanedithiol (EDT) acting as an electron-blocking/hole-extraction layer were reported. These solar cells demonstrated a significant improvement in power conversion efficiency of 8.55% and long-term air stability. Coupled with photocarrier radiometry measurements, this work used a new trap-state mediated exciton hopping transport model, specifically for CQD thin films, to unveil and quantify exciton transport mechanisms through the extraction of hopping transport parameters including exciton lifetimes, hopping diffusivity, exciton detrapping time, and trap-state density. It is shown that PbS-TBAI has higher trap-state density than PbS-EDT that results in higher PbS-EDT exciton lifetimes. Hopping diffusivities of both CQD thin film types show similar temperature dependence, particularly higher temperatures yield higher hopping diffusivity. The higher diffusivity of PbS-TBAI compared with PbS-EDT indicates that PbS-TBAI is a much better photovoltaic material than PbS-EDT. Furthermore, PCR temperature spectra and deep-level photothermal spectroscopy provided additional insights to CQD surface trap states: PbS-TBAI thin films exhibit a single dominant trap level, while PbS-EDT films with lower trap-state densities show multiple trap levels.

  7. Shortwave Radiative Fluxes, Solar-Beam Transmissions, and Aerosol Properties: TARFOX and ACE-2 Find More Absorption from Flux Radiometry than from Other Measurements

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.; Redemann, J.; Schmid, B.; Livingston, J. M.; Bergstrom, R. W.; Ramirez, S. A.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    The Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the Second Aerosol Characterization Experiment (ACE-2) made simultaneous measurements of shortwave radiative fluxes, solar-beam transmissions, and the aerosols affecting those fluxes and transmissions. Besides the measured fluxes and transmissions, other obtained properties include aerosol scattering and absorption measured in situ at the surface and aloft; aerosol single scattering albedo retrieved from skylight radiances; and aerosol complex refractive index derived by combining profiles of backscatter, extinction, and size distribution. These measurements of North Atlantic boundary layer aerosols impacted by anthropogenic pollution revealed the following characteristic results: (1) Better agreement among different types of remote measurements of aerosols (e.g., optical depth, extinction, and backscattering from sunphotometers, satellites, and lidars) than between remote and in situ measurements; 2) More extinction derived from transmission measurements than from in situ measurements; (3) Larger aerosol absorption inferred from flux radiometry than from other measurements. When the measured relationships between downwelling flux and optical depth (or beam transmission) are used to derive best-fit single scattering albedos for the polluted boundary layer aerosol, both TARFOX and ACE-2 yield midvisible values of 0.90 +/- 0.04. The other techniques give larger single scattering albedos (i.e. less absorption) for the polluted boundary layer, with a typical result of 0.95 +/- 0.04. Although the flux-based results have the virtue of describing the column aerosol unperturbed by sampling, they are subject to questions about representativeness and other uncertainties (e.g., unknown gas absorption). Current uncertainties in aerosol single scattering albedo are large in terms of climate effects. They also have an important influence on aerosol optical depths retrieved from satellite radiances

  8. Spectrally resolved modulated infrared radiometry of photothermal, photocarrier, and photoluminescence response of CdSe crystals: Determination of optical, thermal, and electronic transport parameters

    SciTech Connect

    Pawlak, M.; Chirtoc, M.; Horny, N.; Pelzl, J.

    2016-03-28

    Spectrally resolved modulated infrared radiometry (SR-MIRR) with super-band gap photoexcitation is introduced as a self-consistent method for semiconductor characterization (CdSe crystals grown under different conditions). Starting from a theoretical model combining the contributions of the photothermal (PT) and photocarrier (PC) signal components, an expression is derived for the thermal-to-plasma wave transition frequency f{sub tc} which is found to be wavelength-independent. The deviation of the PC component from the model at high frequency is quantitatively explained by a quasi-continuous distribution of carrier recombination lifetimes. The integral, broad frequency band (0.1 Hz–1 MHz) MIRR measurements simultaneously yielded the thermal diffusivity a, the effective IR optical absorption coefficient β{sub eff}, and the bulk carrier lifetime τ{sub c}. Spectrally resolved frequency scans were conducted with interchangeable IR bandpass filters (2.2–11.3 μm) in front of the detector. The perfect spectral match of the PT and PC components is the direct experimental evidence of the key assumption in MIRR that de-exciting carriers are equivalent to blackbody (Planck) radiators. The exploitation of the β spectrum measured by MIRR allowed determining the background (equilibrium) free carrier concentration n{sub 0}. At the shortest wavelength (3.3 μm), the photoluminescence (PL) component supersedes the PC one and has distinct features. The average sample temperature influences the PC component but not the PT one.

  9. Kinetic Damage from Meteorites

    NASA Technical Reports Server (NTRS)

    Cooke, William; Brown, Peter; Matney, Mark

    2017-01-01

    A Near Earth object impacting into Earth's atmosphere may produce damaging effects at the surface due to airblast, thermal pulse, or kinetic impact in the form of meteorites. At large sizes (greater than many tens of meters), the damage is amplified by the hypersonic impact of these large projectiles moving with cosmic velocity, leaving explosively produced craters. However, much more common is simple "kinetic" damage caused by the impact of smaller meteorites moving at terminal speeds. As of this date a handful of instances are definitively known of people or structures being directly hit and/or damaged by the kinetic impact of meteorites. Meteorites known to have struck humans include the Sylacauga, Alabama fall (1954) and the Mbale meteorite fall (1992). Much more common is kinetic meteorite damage to cars, buildings, and even a post box (Claxton, Georgia - 1984). Historical accounts indicate that direct kinetic damage by meteorites may be more common than recent accounts suggest (Yau et al., 1994). In this talk we will examine the contemporary meteorite flux and estimate the frequency of kinetic damage to various structures, as well as how the meteorite flux might affect the rate of human casualties. This will update an earlier study by Halliday et al (1985), adding variations expected in meteorite flux with latitude (Le Feuvre and Wieczorek, 2008) and validating these model predictions of speed and entry angle with observations from the NASA and SOMN fireball networks. In particular, we explore the physical characteristics of bright meteors which may be used as a diagnostic for estimating which fireballs produce meteorites and hence how early warning of such kinetic damage may be estimated in advance through observations and modeling.

  10. Kinetic Damage from Meteorites

    NASA Technical Reports Server (NTRS)

    Cooke, William; Brown, Peter; Matney, Mark

    2017-01-01

    A Near Earth object impacting into Earth's atmosphere may produce damaging effects at the surface due to airblast, thermal pulse, or kinetic impact in the form of meteorites. At large sizes (>many tens of meters), the damage is amplified by the hypersonic impact of these large projectiles moving with cosmic velocity, leaving explosively produced craters. However, much more common is simple "kinetic" damage caused by the impact of smaller meteorites moving at terminal speeds. As of this date a handful of instances are definitively known of people or structures being directly hit and/or damaged by the kinetic impact of meteorites. Meteorites known to have struck humans include the Sylacauga, Alabama fall (1954) and the Mbale meteorite fall (1992). Much more common is kinetic meteorite damage to cars, buildings, and even a post box (Claxton, Georgia - 1984). Historical accounts indicate that direct kinetic damage by meteorites may be more common than recent accounts suggest (Yau et al., 1994). In this talk we will examine the contemporary meteorite flux and estimate the frequency of kinetic damage to various structures, as well as how the meteorite flux might affect the rate of human casualties. This will update an earlier study by Halliday et al (1985), adding variations expected in meteorite flux with latitude (Le Feuvre and Wieczorek, 2008) and validating these model predictions of speed and entry angle with observations from the NASA and SOMN fireball networks. In particular, we explore the physical characteristics of bright meteors which may be used as a diagnostic for estimating which fireballs produce meteorites and hence how early warning of such kinetic damage may be estimated in advance through observations and modelling.

  11. Multiple alternative substrate kinetics.

    PubMed

    Anderson, Vernon E

    2015-11-01

    The specificity of enzymes for their respective substrates has been a focal point of enzyme kinetics since the initial characterization of metabolic chemistry. Various processes to quantify an enzyme's specificity using kinetics have been utilized over the decades. Fersht's definition of the ratio kcat/Km for two different substrates as the "specificity constant" (ref [7]), based on the premise that the important specificity existed when the substrates were competing in the same reaction, has become a consensus standard for enzymes obeying Michaelis-Menten kinetics. The expansion of the theory for the determination of the relative specificity constants for a very large number of competing substrates, e.g. those present in a combinatorial library, in a single reaction mixture has been developed in this contribution. The ratio of kcat/Km for isotopologs has also become a standard in mechanistic enzymology where kinetic isotope effects have been measured by the development of internal competition experiments with extreme precision. This contribution extends the theory of kinetic isotope effects to internal competition between three isotopologs present at non-tracer concentrations in the same reaction mix. This article is part of a special issue titled: Enzyme Transition States from Theory and Experiment. Published by Elsevier B.V.

  12. Erbium hydride decomposition kinetics.

    SciTech Connect

    Ferrizz, Robert Matthew

    2006-11-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

  13. Relativistic Chiral Kinetic Theory

    NASA Astrophysics Data System (ADS)

    Stephanov, Mikhail

    2016-12-01

    This very brief review of the recent progress in chiral kinetic theory is based on the results of Refs. [J.-Y. Chen, D. T. Son, M. A. Stephanov, H.-U. Yee, Y. Yin, Lorentz Invariance in Chiral Kinetic Theory, Phys. Rev. Lett. 113 (18) (2014) 182302. doi:10.1103/PhysRevLett.113.182302; J.-Y. Chen, D. T. Son, M. A. Stephanov, Collisions in Chiral Kinetic Theory, Phys. Rev. Lett. 115 (2) (2015) 021601. doi: 10.1103/PhysRevLett.115.021601; M. A. Stephanov, H.-U. Yee, The no-drag frame for anomalous chiral fluid, Phys. Rev. Lett. 116 (12) (2016) 122302. doi: 10.1103/PhysRevLett.116.122302].

  14. Annual, semi-annual and ter-annual variations of gravity wave momentum flux in 13 years of SABER data

    NASA Astrophysics Data System (ADS)

    Chen, Dan; Preusse, Peter; Ern, Manfred; Strube, Cornelia

    2017-04-01

    both hemispheres and equatorial mesopause. Using these four dominant components of time scales and performing sinusoidal fits of GWMF we find that the patterns also at high latitudes are consistent with the range of 50°S to 50°N continuously covered by SABER.

  15. Relativistic Kinetic Theory

    NASA Astrophysics Data System (ADS)

    Vereshchagin, Gregory V.; Aksenov, Alexey G.

    2017-02-01

    Preface; Acknowledgements; Acronyms and definitions; Introduction; Part I. Theoretical Foundations: 1. Basic concepts; 2. Kinetic equation; 3. Averaging; 4. Conservation laws and equilibrium; 5. Relativistic BBGKY hierarchy; 6. Basic parameters in gases and plasmas; Part II. Numerical Methods: 7. The basics of computational physics; 8. Direct integration of Boltzmann equations; 9. Multidimensional hydrodynamics; Part III. Applications: 10. Wave dispersion in relativistic plasma; 11. Thermalization in relativistic plasma; 12. Kinetics of particles in strong fields; 13. Compton scattering in astrophysics and cosmology; 14. Self-gravitating systems; 15. Neutrinos, gravitational collapse and supernovae; Appendices; Bibliography; Index.

  16. Modular kinetic analysis.

    PubMed

    Krab, Klaas

    2011-01-01

    Modularization is an important strategy to tackle the study of complex biological systems. Modular kinetic analysis (MKA) is a quantitative method to extract kinetic information from such a modularized system that can be used to determine the control and regulatory structure of the system, and to pinpoint and quantify the interaction of effectors with the system. The principles of the method are described, and the relation with metabolic control analysis is discussed. Examples of application of MKA are given. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Kinetics and Catalysis Demonstrations.

    ERIC Educational Resources Information Center

    Falconer, John L.; Britten, Jerald A.

    1984-01-01

    Eleven videotaped kinetics and catalysis demonstrations are described. Demonstrations include the clock reaction, oscillating reaction, hydrogen oxidation in air, hydrogen-oxygen explosion, acid-base properties of solids, high- and low-temperature zeolite reactivity, copper catalysis of ammonia oxidation and sodium peroxide decomposition, ammonia…

  18. Kinetic tetrazolium microtiter assay

    NASA Technical Reports Server (NTRS)

    Pierson, Duane L. (Inventor); Stowe, Raymond P. (Inventor); Koeing, David W. (Inventor)

    1992-01-01

    A method for conducting an in vitro cell assay using a tetrazolium indicator is disclosed. The indicator includes a nonionic detergent which solubilizes a tetrazolium reduction product in vitro and has low toxicity for the cells. The incubation of test cells in the presence of zolium bromide and octoxynol (TRITON X-100) permits kinetics of the cell metabolism to be determined.

  19. Radiation damage annealing kinetics

    NASA Technical Reports Server (NTRS)

    Dresselhaus, M. S.

    1971-01-01

    Various spectral response studies are reported that assess lithium doping effects on the recovery process of electron damaged silicon solar cells. Measurements of both the minority carrier lifetimes and the energy level spectrum of the defects are used to predict lifetime damage constants and carrier removal rates relevant to the operation of the solar lithium-doped cell and its annealing kinetics.

  20. Kinetics and Catalysis Demonstrations.

    ERIC Educational Resources Information Center

    Falconer, John L.; Britten, Jerald A.

    1984-01-01

    Eleven videotaped kinetics and catalysis demonstrations are described. Demonstrations include the clock reaction, oscillating reaction, hydrogen oxidation in air, hydrogen-oxygen explosion, acid-base properties of solids, high- and low-temperature zeolite reactivity, copper catalysis of ammonia oxidation and sodium peroxide decomposition, ammonia…

  1. Applications of kinetic theory

    SciTech Connect

    Gidaspow, D.

    1992-01-01

    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. This report presents the author's derivation of analytical solutions useful in understanding the operation of a CFB. The report is in a form of a chapter that reviews the kinetic theory applications.

  2. Oxidative desulfurization: kinetic modelling.

    PubMed

    Dhir, S; Uppaluri, R; Purkait, M K

    2009-01-30

    Increasing environmental legislations coupled with enhanced production of petroleum products demand, the deployment of novel technologies to remove organic sulfur efficiently. This work represents the kinetic modeling of ODS using H(2)O(2) over tungsten-containing layered double hydroxide (LDH) using the experimental data provided by Hulea et al. [V. Hulea, A.L. Maciuca, F. Fajula, E. Dumitriu, Catalytic oxidation of thiophenes and thioethers with hydrogen peroxide in the presence of W-containing layered double hydroxides, Appl. Catal. A: Gen. 313 (2) (2006) 200-207]. The kinetic modeling approach in this work initially targets the scope of the generation of a superstructure of micro-kinetic reaction schemes and models assuming Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms. Subsequently, the screening and selection of above models is initially based on profile-based elimination of incompetent schemes followed by non-linear regression search performed using the Levenberg-Marquardt algorithm (LMA) for the chosen models. The above analysis inferred that Eley-Rideal mechanism describes the kinetic behavior of ODS process using tungsten-containing LDH, with adsorption of reactant and intermediate product only taking place on the catalyst surface. Finally, an economic index is presented that scopes the economic aspects of the novel catalytic technology with the parameters obtained during regression analysis to conclude that the cost factor for the catalyst is 0.0062-0.04759 US $ per barrel.

  3. Development of a Geomagnetic Storm Correction to the International Reference Ionosphere E-Region Electron Densities Using TIMED/SABER Observations

    NASA Technical Reports Server (NTRS)

    Mertens, C. J.; Xu, X.; Fernandez, J. R.; Bilitza, D.; Russell, J. M., III; Mlynczak, M. G.

    2009-01-01

    Auroral infrared emission observed from the TIMED/SABER broadband 4.3 micron channel is used to develop an empirical geomagnetic storm correction to the International Reference Ionosphere (IRI) E-region electron densities. The observation-based proxy used to develop the storm model is SABER-derived NO+(v) 4.3 micron volume emission rates (VER). A correction factor is defined as the ratio of storm-time NO+(v) 4.3 micron VER to a quiet-time climatological averaged NO+(v) 4.3 micron VER, which is linearly fit to available geomagnetic activity indices. The initial version of the E-region storm model, called STORM-E, is most applicable within the auroral oval region. The STORM-E predictions of E-region electron densities are compared to incoherent scatter radar electron density measurements during the Halloween 2003 storm events. Future STORM-E updates will extend the model outside the auroral oval.

  4. LLNL Chemical Kinetics Modeling Group

    SciTech Connect

    Pitz, W J; Westbrook, C K; Mehl, M; Herbinet, O; Curran, H J; Silke, E J

    2008-09-24

    The LLNL chemical kinetics modeling group has been responsible for much progress in the development of chemical kinetic models for practical fuels. The group began its work in the early 1970s, developing chemical kinetic models for methane, ethane, ethanol and halogenated inhibitors. Most recently, it has been developing chemical kinetic models for large n-alkanes, cycloalkanes, hexenes, and large methyl esters. These component models are needed to represent gasoline, diesel, jet, and oil-sand-derived fuels.

  5. An Introductory Level Kinetics Investigation.

    ERIC Educational Resources Information Center

    McGarvey, J. E. B.; Knipe, A. C.

    1980-01-01

    Provides a list of the reactions commonly used for introductory kinetics studies. These reactions illustrate the kinetics concepts of rate law, rate constant, and reaction order. Describes a kinetic study of the hydrolysis of 3-bromo-3-phenylpropanoic acid which offers many educational advantages. (CS)

  6. An Introductory Level Kinetics Investigation.

    ERIC Educational Resources Information Center

    McGarvey, J. E. B.; Knipe, A. C.

    1980-01-01

    Provides a list of the reactions commonly used for introductory kinetics studies. These reactions illustrate the kinetics concepts of rate law, rate constant, and reaction order. Describes a kinetic study of the hydrolysis of 3-bromo-3-phenylpropanoic acid which offers many educational advantages. (CS)

  7. Kinetic Tetrazolium Microtiter Assay

    NASA Technical Reports Server (NTRS)

    Pierson, Duane L.; Stowe, Raymond; Koenig, David

    1993-01-01

    Kinetic tetrazolium microtiter assay (KTMA) involves use of tetrazolium salts and Triton X-100 (or equivalent), nontoxic, in vitro color developer solubilizing colored metabolite formazan without injuring or killing metabolizing cells. Provides for continuous measurement of metabolism and makes possible to determine rate of action of antimicrobial agent in real time as well as determines effective inhibitory concentrations. Used to monitor growth after addition of stimulatory compounds. Provides for kinetic determination of efficacy of biocide, greatly increasing reliability and precision of results. Also used to determine relative effectiveness of antimicrobial agent as function of time. Capability of generating results on day of test extremely important in treatment of water and waste, disinfection of hospital rooms, and in pharmaceutical, agricultural, and food-processing industries. Assay also used in many aspects of cell biology.

  8. Kinetic Tetrazolium Microtiter Assay

    NASA Technical Reports Server (NTRS)

    Pierson, Duane L.; Stowe, Raymond; Koenig, David

    1993-01-01

    Kinetic tetrazolium microtiter assay (KTMA) involves use of tetrazolium salts and Triton X-100 (or equivalent), nontoxic, in vitro color developer solubilizing colored metabolite formazan without injuring or killing metabolizing cells. Provides for continuous measurement of metabolism and makes possible to determine rate of action of antimicrobial agent in real time as well as determines effective inhibitory concentrations. Used to monitor growth after addition of stimulatory compounds. Provides for kinetic determination of efficacy of biocide, greatly increasing reliability and precision of results. Also used to determine relative effectiveness of antimicrobial agent as function of time. Capability of generating results on day of test extremely important in treatment of water and waste, disinfection of hospital rooms, and in pharmaceutical, agricultural, and food-processing industries. Assay also used in many aspects of cell biology.

  9. Kinetic Damage from Meteorites

    NASA Technical Reports Server (NTRS)

    Cooke, W.; Matney, M.; Brown, P.

    2017-01-01

    Comparing the natural meteorite flux at the Earth's surface to that of space debris, reentering debris is approx. 2 orders of magnitude less of a kinetic hazard at all but the very largest (and therefore rarest) sizes compared to natural impactors. Debris re-entries over several metric tonnes are roughly as frequent as natural impactors, but the survival fraction is expected to be much higher. Kinetic hazards from meteorites are very small, with only one recorded (indirect) injury reported. We expect fatalities to be even more rare, on the order of one person killed per several millennia. That several reports exist of small fragments/sand hitting people during meteorite falls is consistent with our prediction that this should occur every decade or so.

  10. Kinetic Damage from Meteorites

    NASA Technical Reports Server (NTRS)

    Cooke, W.; Brown, P.; Matney, M.

    2017-01-01

    Comparing the natural meteorite flux at the Earth's surface to that of space debris, re-entering debris is 2 orders of magnitude less of a kinetic hazard at all but the very largest (and therefore rarest) sizes compared to natural impactors. Debris re-entries over several metric tonnes are roughly as frequent as natural impactors, but the survival fraction is expected to be much higher. Kinetic hazards from meteorites are very small, with only one recorded (indirect) injury reported. We expect fatalities to be even more rare, on the order of one person killed per several millennia. That several reports exist of small fragments/sand hitting people during meteorite falls is consistent with our prediction that this should occur every decade or so.

  11. Kinetic Theory of Gases

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The theory, developed in the nineteenth century, notably by Rudolf Clausius (1822-88) and James Clerk Maxwell (1831-79), that the properties of a gas (temperature, pressure, etc) could be described in terms of the motions (and kinetic energy) of the molecules comprising the gases. The theory has wide implications in astrophysics. In particular, the perfect gas law, which relates the pressure, vol...

  12. Homogeneous nucleation kinetics

    NASA Technical Reports Server (NTRS)

    Rasmussen, D. H.; Appleby, M. R.; Leedom, G. L.; Babu, S. V.; Naumann, R. J.

    1983-01-01

    Homogeneous nucleation kinetics are rederived in a manner fundamentally similar to the approach of classical nucleation theory with the following modifications and improvements. First, the cluster is a parent phase cluster and does not require energization to the parent state. Second, the thermodynamic potential used to describe phase stability is a continuous function along the pathway of phase decomposition. Third, the kinetics of clustering corresponds directly to the diffusional flux of monomers through the cluster distribution and are formally similar to classical theory with the resulting kinetic equation modified by two terms in the preexponential factor. These terms correct for the influence of a supersaturation dependent clustering within the parent phase and for the influence of an asymmetrical cluster concentration as a function of cluster size at the critical cluster size. Fourth, the supersaturation dependence of the nucleation rate is of the same form as that given by classical nucleation theory. This supersaturation dependence must however be interpreted in terms of a size dependent surface tension. Finally, there are two scaling laws which describe supersaturation to either constant nucleation rate or to the thermodynamically determined physical spinodal.

  13. Calcite Dissolution Kinetics

    NASA Astrophysics Data System (ADS)

    Berelson, W.; Subhas, A.; Dong, S.; Naviaux, J.; Adkins, J. F.

    2016-12-01

    A geological buffer for high atmospheric CO2 concentrations is neutralization via reaction with CaCO3. We have been studying the dissolution kinetics of carbonate minerals using labeled 13C calcite and Picarro-based measurements of 13C enrichments in solution DIC. This methodology has greatly facilitated our investigation of dissolution kinetics as a function of water carbonate chemistry, temperature and pressure. One can adjust the saturation state Omega by changing the ion activity product (e.g. adjusting carbonate ion concentration), or by changing the solubility product (e.g. adjusting temperature or pressure). The canonical formulation of dissolution rate vs. omega has been refined (Subhas et al. 2015) and shows distinct non-linear behavior near equilibrium and rates in sea water of 1-3 e-6 g/cm2day at omega = 0.8. Carbonic anhydrase (CA), an enzyme that catalyzes the hydration of dissolved CO2 to carbonic acid, was shown (in concentrations <=0.04 g/L) to enhance the dissolution rate at low degrees of undersaturation by >500x. This result points to the importance of carbonic acid in enhancing dissolution at low degrees of undersaturation. CA activity and abundance in nature must be considered regarding the role it plays in catalyzing dissolution. We also have been investigating the role of temperature on dissolution kinetics. An increase of 16C yields an order of magnitude increase in dissolution rate. Temperature (and P) also change Omega critical, the saturation state where dissolution rates change substantially. Increasing pressure (achieved in a pressure reaction chamber we built) also shifts Omega critical closer to equilibrium and small pressure increases have large impact on dissolution kinetics. Dissolution rates are enhanced by an order of magnitude for a change in pressure of 1500 psi relative to the dissolution rate achieved by water chemistry effects alone for an omega of 0.8. We've shown that the thermodynamic determination of saturation state

  14. Millimeter Wave Atmospheric Radiometry Observations.

    DTIC Science & Technology

    1981-03-27

    structure of the atmosphere would be very important. Rufton [20] combined thermal sensor technology for microthermal measurements with radiosonde...fromT2 h n relationships with CT(h) at least for optical effects. Bufton obtained the mean-square temperature difference between two microthermal probes

  15. Radiometry of water turbidity measurements

    NASA Technical Reports Server (NTRS)

    Mccluney, W. R.

    1974-01-01

    An examination of a number of measurements of turbidity reported in the literature reveals considerable variability in the definitions, units, and measurement techniques used. Many of these measurements differ radically in the optical quantity measured. The radiometric basis of each of the most common definitions of turbidity is examined. Several commercially available turbidimeters are described and their principles of operation are evaluated radiometrically. It is recommended that the term turbidity be restricted to measurements based upon the light scattered by the sample with that scattered by standard suspensions of known turbidity. It is also recommended that the measurement procedure be standardized by requiring the use of Formazin as the turbidity standardizing material and that the Formazin Turbidity Unit (FTU) be adopted as the standard unit of turbidity.

  16. Quantum Cloning for Absolute Radiometry

    SciTech Connect

    Sanguinetti, Bruno; Pomarico, Enrico; Sekatski, Pavel; Zbinden, Hugo; Gisin, Nicolas

    2010-08-20

    In the quantum regime information can be copied with only a finite fidelity. This fidelity gradually increases to 1 as the system becomes classical. In this Letter we show how this fact can be used to directly measure the amount of radiated power. We demonstrate how these principles can be used to build a practical primary standard.

  17. Polarimetric radiometry of natural scenes

    NASA Astrophysics Data System (ADS)

    Wikner, David A.

    2002-07-01

    This paper presents our group's most recent passive millimeter-wave (MMW) measurements made using a 94-GHz Stokes-vector radiometer. Included are images and analyses of treeline data. These data were collected to investigate the possible use of passive MMW sensors to perform the helicopter collision avoidance task. The treeline data presented were collected in both the summer and winter. The results of the analysis show that in the winter the detection of the treeline can be straightforward because of an often-low horizon sky brightness temperature. The contrast between the tree branches and the horizon are seen in the data to be about 10 - 15 K. The summer case, however, shows a horizon sky-to-tree brightness temperature ratio of about 1. A simple statistical analysis of the summer image shows that the trees, in our case, can be distinguished from the horizon sky based upon the statistical parameters alone.

  18. Dental Photothermal Radiometry: Theoretical Analysis.

    NASA Astrophysics Data System (ADS)

    Matvienko, Anna; Jeon, Raymond; Mandelis, Andreas; Abrams, Stephen

    2007-03-01

    Dental enamel demineralization in its early stages is very difficult to detect with conventional x-rays or visual examination. High-resolution techniques, such as scanning electron microscopy, usually require destruction of the tooth. Photothermal Radiomety (PTR) was recently applied as a safe, non-destructive, and highly sensitive tool for the detection of early dental demineralization, artificially created on the enamel surface. The experiments showed very high sensitivity of the measured signal to incipient changes in the surface structure, emphasizing the clinical capabilities of the method. In order to analyze the biothermophotonic phenomena in a tooth sample during the photothermal excitation, a theoretical model featuring coupled diffuse-photon-density-wave and thermal-wave fields was developed. Numerical simulations identified the effects on the PTR signal of changes in optical and thermal properties of enamel and dentin as a result of demineralization. The model predictions and experimental results will be compared and discussed.

  19. Ionospheric E-Region Response to Solar-Geomagnetic Storms Observed by TIMED/SABER and Application to IRI Storm-Model Development

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Mast, Jeffrey C.; Winick, Jeremy R.; Russell, James M., III; Mlynczak, Martin G.; Evans, David S.

    2007-01-01

    The large thermospheric infrared radiance enhancements observed from the TIMED/SABER experiment during recent solar storms provide an exciting opportunity to study the influence of solar-geomagnetic disturbances on the upper atmosphere and ionosphere. In particular, nighttime enhancements of 4.3 um emission, due to vibrational excitation and radiative emission by NO+, provide an excellent proxy to study and analyze the response of the ionospheric E-region to auroral electron dosing and storm-time enhancements to the E-region electron density. In this paper we give a status report of on-going work on model and data analysis methodologies of deriving NO+ 4.3 um volume emission rates, a proxy for the storm-time E-region response, and the approach for deriving an empirical storm-time correction to International Reference Ionosphere (IRI) E-region NO+ and electron densities.

  20. Empirical Storm-Time Correction to the International Reference Ionosphere Model E-Region Electron and Ion Density Parameterizations Using Observations from TIMED/SABER

    NASA Technical Reports Server (NTRS)

    Mertens, Christoper J.; Winick, Jeremy R.; Russell, James M., III; Mlynczak, Martin G.; Evans, David S.; Bilitza, Dieter; Xu, Xiaojing

    2007-01-01

    The response of the ionospheric E-region to solar-geomagnetic storms can be characterized using observations of infrared 4.3 micrometers emission. In particular, we utilize nighttime TIMED/SABER measurements of broadband 4.3 micrometers limb emission and derive a new data product, the NO+(v) volume emission rate, which is our primary observation-based quantity for developing an empirical storm-time correction the IRI E-region electron density. In this paper we describe our E-region proxy and outline our strategy for developing the empirical storm model. In our initial studies, we analyzed a six day storm period during the Halloween 2003 event. The results of this analysis are promising and suggest that the ap-index is a viable candidate to use as a magnetic driver for our model.

  1. Using a Novel Absolute Ontogenetic Age Determination Technique to Calculate the Timing of Tooth Eruption in the Saber-Toothed Cat, Smilodon fatalis

    PubMed Central

    Wysocki, M. Aleksander; Feranec, Robert S.; Tseng, Zhijie Jack; Bjornsson, Christopher S.

    2015-01-01

    Despite the superb fossil record of the saber-toothed cat, Smilodon fatalis, ontogenetic age determination for this and other ancient species remains a challenge. The present study utilizes a new technique, a combination of data from stable oxygen isotope analyses and micro-computed tomography, to establish the eruption rate for the permanent upper canines in Smilodon fatalis. The results imply an eruption rate of 6.0 millimeters per month, which is similar to a previously published average enamel growth rate of the S. fatalis upper canines (5.8 millimeters per month). Utilizing the upper canine growth rate, the upper canine eruption rate, and a previously published tooth replacement sequence, this study calculates absolute ontogenetic age ranges of tooth development and eruption in S. fatalis. The timing of tooth eruption is compared between S. fatalis and several extant conical-toothed felids, such as the African lion (Panthera leo). Results suggest that the permanent dentition of S. fatalis, except for the upper canines, was fully erupted by 14 to 22 months, and that the upper canines finished erupting at about 34 to 41 months. Based on these developmental age calculations, S. fatalis individuals less than 4 to 7 months of age were not typically preserved at Rancho La Brea. On the whole, S. fatalis appears to have had delayed dental development compared to dental development in similar-sized extant felids. This technique for absolute ontogenetic age determination can be replicated in other ancient species, including non-saber-toothed taxa, as long as the timing of growth initiation and growth rate can be determined for a specific feature, such as a tooth, and that growth period overlaps with the development of the other features under investigation. PMID:26132165

  2. Using a Novel Absolute Ontogenetic Age Determination Technique to Calculate the Timing of Tooth Eruption in the Saber-Toothed Cat, Smilodon fatalis.

    PubMed

    Wysocki, M Aleksander; Feranec, Robert S; Tseng, Zhijie Jack; Bjornsson, Christopher S

    2015-01-01

    Despite the superb fossil record of the saber-toothed cat, Smilodon fatalis, ontogenetic age determination for this and other ancient species remains a challenge. The present study utilizes a new technique, a combination of data from stable oxygen isotope analyses and micro-computed tomography, to establish the eruption rate for the permanent upper canines in Smilodon fatalis. The results imply an eruption rate of 6.0 millimeters per month, which is similar to a previously published average enamel growth rate of the S. fatalis upper canines (5.8 millimeters per month). Utilizing the upper canine growth rate, the upper canine eruption rate, and a previously published tooth replacement sequence, this study calculates absolute ontogenetic age ranges of tooth development and eruption in S. fatalis. The timing of tooth eruption is compared between S. fatalis and several extant conical-toothed felids, such as the African lion (Panthera leo). Results suggest that the permanent dentition of S. fatalis, except for the upper canines, was fully erupted by 14 to 22 months, and that the upper canines finished erupting at about 34 to 41 months. Based on these developmental age calculations, S. fatalis individuals less than 4 to 7 months of age were not typically preserved at Rancho La Brea. On the whole, S. fatalis appears to have had delayed dental development compared to dental development in similar-sized extant felids. This technique for absolute ontogenetic age determination can be replicated in other ancient species, including non-saber-toothed taxa, as long as the timing of growth initiation and growth rate can be determined for a specific feature, such as a tooth, and that growth period overlaps with the development of the other features under investigation.

  3. Kinetics of stress fibers

    NASA Astrophysics Data System (ADS)

    Stachowiak, Matthew R.; O'Shaughnessy, Ben

    2008-02-01

    Stress fibers are contractile cytoskeletal structures, tensile actomyosin bundles which allow sensing and production of force, provide cells with adjustable rigidity and participate in various processes such as wound healing. The stress fiber is possibly the best characterized and most accessible multiprotein cellular contractile machine. Here we develop a quantitative model of the structure and relaxation kinetics of stress fibers. The principal experimentally known features are incorporated. The fiber has a periodic sarcomeric structure similar to muscle fibers with myosin motor proteins exerting contractile force by pulling on actin filaments. In addition the fiber contains the giant spring-like protein titin. Actin is continuously renewed by exchange with the cytosol leading to a turnover time of several minutes. In order that steady state be possible, turnover must be regulated. Our model invokes simple turnover and regulation mechanisms: actin association and dissociation occur at filament ends, while actin filament overlap above a certain threshold in the myosin-containing regions augments depolymerization rates. We use the model to study stress fiber relaxation kinetics after stimulation, as observed in a recent experimental study where some fiber regions were contractile and others expansive. We find that two distinct episodes ensue after stimulation: the turnover-overlap system relaxes rapidly in seconds, followed by the slow relaxation of sarcomere lengths in minutes. For parameter values as they have been characterized experimentally, we find the long time relaxation of sarcomere length is set by the rate at which actin filaments can grow or shrink in response to the forces exerted by the elastic and contractile elements. Consequently, the stress fiber relaxation time scales inversely with both titin spring constant and the intrinsic actin turnover rate. The model's predicted sarcomere velocities and contraction-expansion kinetics are in good

  4. Chemical kinetics modeling

    SciTech Connect

    Westbrook, C.K.; Pitz, W.J.

    1993-12-01

    This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

  5. Analysis of Crystallization Kinetics

    NASA Technical Reports Server (NTRS)

    Kelton, Kenneth F.

    1997-01-01

    A realistic computer model for polymorphic crystallization (i.e., initial and final phases with identical compositions), which includes time-dependent nucleation and cluster-size-dependent growth rates, is developed and tested by fits to experimental data. Model calculations are used to assess the validity of two of the more common approaches for the analysis of crystallization data. The effects of particle size on transformation kinetics, important for the crystallization of many systems of limited dimension including thin films, fine powders, and nanoparticles, are examined.

  6. Diffusion Influenced Adsorption Kinetics.

    PubMed

    Miura, Toshiaki; Seki, Kazuhiko

    2015-08-27

    When the kinetics of adsorption is influenced by the diffusive flow of solutes, the solute concentration at the surface is influenced by the surface coverage of solutes, which is given by the Langmuir-Hinshelwood adsorption equation. The diffusion equation with the boundary condition given by the Langmuir-Hinshelwood adsorption equation leads to the nonlinear integro-differential equation for the surface coverage. In this paper, we solved the nonlinear integro-differential equation using the Grünwald-Letnikov formula developed to solve fractional kinetics. Guided by the numerical results, analytical expressions for the upper and lower bounds of the exact numerical results were obtained. The upper and lower bounds were close to the exact numerical results in the diffusion- and reaction-controlled limits, respectively. We examined the validity of the two simple analytical expressions obtained in the diffusion-controlled limit. The results were generalized to include the effect of dispersive diffusion. We also investigated the effect of molecular rearrangement of anisotropic molecules on surface coverage.

  7. Kinetics of fiber solidification

    PubMed Central

    Mercader, C.; Lucas, A.; Derré, A.; Zakri, C.; Moisan, S.; Maugey, M.; Poulin, P.

    2010-01-01

    Many synthetic or natural fibers are produced via the transformation of a liquid solution into a solid filament, which allows the wet processing of high molecular weight polymers, proteins, or inorganic particles. Synthetic wet-spun fibers are used in our everyday life from clothing to composite reinforcement applications. Spun fibers are also common in nature. Silk solidification results from the coagulation of protein solutions. The chemical phenomena involved in the formation of all these classes of fibers can be quite different but they all share the same fundamental transformation from a liquid to a solid state. The solidification process is critical because it governs the production rate and the strength that fibers can sustain to be drawn and wound. An approach is proposed in this work to investigate the kinetics of fiber solidification. This approach consists in circulating solidifying fibers in the extensional flow of a surrounding liquid. Such as polymers in extensional flows, the fibers break if resultant drag forces exceed the fiber tensile strength. The solidification kinetics of nanotube composite fibers serves as a validation example of this approach. The method could be extended to other systems and advance thereby the science and technology of fiber and textile materials. It is also a way to directly visualize the scission of chain-like systems in extensional flows. PMID:20937910

  8. Kinetics of coal pyrolysis

    SciTech Connect

    Seery, D.J.; Freihaut, J.D.; Proscia, W.M. ); Howard, J.B.; Peters, W.; Hsu, J.; Hajaligol, M.; Sarofim, A. ); Jenkins, R.; Mallin, J.; Espindola-Merin, B. ); Essenhigh, R.; Misra, M.K. )

    1989-07-01

    This report contains results of a coordinated, multi-laboratory investigation of coal devolatilization. Data is reported pertaining to the devolatilization for bituminous coals over three orders of magnitude in apparent heating rate (100 to 100,000 + {degree}C/sec), over two orders of magnitude in particle size (20 to 700 microns), final particle temperatures from 400 to 1600{degree}C, heat transfer modes ranging from convection to radiative, ambient pressure ranging from near vacuum to one atmosphere pressure. The heat transfer characteristics of the reactors are reported in detail. It is assumed the experimental results are to form the basis of a devolatilization data base. Empirical rate expressions are developed for each phase of devolatilization which, when coupled to an awareness of the heat transfer rate potential of a particular devolatilization reactor, indicate the kinetics emphasized by a particular system reactor plus coal sample. The analysis indicates the particular phase of devolatilization that will be emphasized by a particular reactor type and, thereby, the kinetic expressions appropriate to that devolatilization system. Engineering rate expressions are developed from the empirical rate expressions in the context of a fundamental understanding of coal devolatilization developed in the course of the investigation. 164 refs., 223 figs., 44 tabs.

  9. Stochastic Kinetics of Nascent RNA

    NASA Astrophysics Data System (ADS)

    Xu, Heng; Skinner, Samuel O.; Sokac, Anna Marie; Golding, Ido

    2016-09-01

    The stochastic kinetics of transcription is typically inferred from the distribution of RNA numbers in individual cells. However, cellular RNA reflects additional processes downstream of transcription, hampering this analysis. In contrast, nascent (actively transcribed) RNA closely reflects the kinetics of transcription. We present a theoretical model for the stochastic kinetics of nascent RNA, which we solve to obtain the probability distribution of nascent RNA per gene. The model allows us to evaluate the kinetic parameters of transcription from single-cell measurements of nascent RNA. The model also predicts surprising discontinuities in the distribution of nascent RNA, a feature which we verify experimentally.

  10. Chemical kinetics on extrasolar planets.

    PubMed

    Moses, Julianne I

    2014-04-28

    Chemical kinetics plays an important role in controlling the atmospheric composition of all planetary atmospheres, including those of extrasolar planets. For the hottest exoplanets, the composition can closely follow thermochemical-equilibrium predictions, at least in the visible and infrared photosphere at dayside (eclipse) conditions. However, for atmospheric temperatures approximately <2000K, and in the uppermost atmosphere at any temperature, chemical kinetics matters. The two key mechanisms by which kinetic processes drive an exoplanet atmosphere out of equilibrium are photochemistry and transport-induced quenching. I review these disequilibrium processes in detail, discuss observational consequences and examine some of the current evidence for kinetic processes on extrasolar planets.

  11. A prospectus on kinetic heliophysics

    NASA Astrophysics Data System (ADS)

    Howes, Gregory G.

    2017-05-01

    Under the low density and high temperature conditions typical of heliospheric plasmas, the macroscopic evolution of the heliosphere is strongly affected by the kinetic plasma physics governing fundamental microphysical mechanisms. Kinetic turbulence, collisionless magnetic reconnection, particle acceleration, and kinetic instabilities are four poorly understood, grand-challenge problems that lie at the new frontier of kinetic heliophysics. The increasing availability of high cadence and high phase-space resolution measurements of particle velocity distributions by current and upcoming spacecraft missions and of massively parallel nonlinear kinetic simulations of weakly collisional heliospheric plasmas provides the opportunity to transform our understanding of these kinetic mechanisms through the full utilization of the information contained in the particle velocity distributions. Several major considerations for future investigations of kinetic heliophysics are examined. Turbulent dissipation followed by particle heating is highlighted as an inherently two-step process in weakly collisional plasmas, distinct from the more familiar case in fluid theory. Concerted efforts must be made to tackle the big-data challenge of visualizing the high-dimensional (3D-3V) phase space of kinetic plasma theory through physics-based reductions. Furthermore, the development of innovative analysis methods that utilize full velocity-space measurements, such as the field-particle correlation technique, will enable us to gain deeper insight into these four grand-challenge problems of kinetic heliophysics. A systems approach to tackle the multi-scale problem of heliophysics through a rigorous connection between the kinetic physics at microscales and the self-consistent evolution of the heliosphere at macroscales will propel the field of kinetic heliophysics into the future.

  12. Variability of OH rotational temperatures on time scales from hours to 15 years by kinetic temperature variations, emission layer changes, and non-LTE effects

    NASA Astrophysics Data System (ADS)

    Noll, Stefan

    2016-07-01

    Rotational temperatures derived from hydroxyl (OH) line emission are frequently used to study atmospheric temperatures at altitudes of about 87 km. While the measurement only requires intensities of a few bright lines of an OH band, the interpretation can be complicated. Ground-based temperatures are averages for the entire, typically 8 km wide emission layer. Variations in the rotational temperature are then caused by changes of the kinetic temperature and the OH emission profile. The latter can also be accompanied by differences in the layer-averaged efficiency of the thermalisation of the OH rotational level populations. Since this especially depends on the frequency of collisions with O_2, which is low at high altitudes, the non-local thermodynamic equilibrium (non-LTE) contribution to the measured temperatures can be significant and variable. In order to understand the impact of the different sources of OH rotational temperature variations from time scales of hours to a solar cycle, we have studied spectra from the astronomical echelle spectrographs X-shooter and UVES located at Cerro Paranal in Chile. While the X-shooter data spanning 3.5 years allowed us to measure temperatures for 25 OH and two O_2 bands, the UVES spectra cover no more than 10 OH bands simultaneously but a period of about 15 years. These data have been complemented by kinetic temperature and OH and O_2 emission profiles from the multi-channel radiometer SABER on the TIMED satellite. Taking the O_2 and SABER kinetic temperatures as reference and considering the different band-dependent emission profiles, we could evaluate the contribution of non-LTE effects to the measured OH rotational temperatures depending on line set, band, and time. Non-LTE contributions are significant for most bands and can exceed 10 K. The amplitudes of their average nocturnal and seasonal variation are of the order of 1 to 2 K.

  13. Kinetic inductance magnetometer.

    PubMed

    Luomahaara, Juho; Vesterinen, Visa; Grönberg, Leif; Hassel, Juha

    2014-09-10

    Sensing ultra-low magnetic fields has various applications in the fields of science, medicine and industry. There is a growing need for a sensor that can be operated in ambient environments where magnetic shielding is limited or magnetic field manipulation is involved. To this end, here we demonstrate a new magnetometer with high sensitivity and wide dynamic range. The device is based on the current nonlinearity of superconducting material stemming from kinetic inductance. A further benefit of our approach is of extreme simplicity: the device is fabricated from a single layer of niobium nitride. Moreover, radio frequency multiplexing techniques can be applied, enabling the simultaneous readout of multiple sensors, for example, in biomagnetic measurements requiring data from large sensor arrays.

  14. Kinetics of Social Contagion.

    PubMed

    Ruan, Zhongyuan; Iñiguez, Gerardo; Karsai, Márton; Kertész, János

    2015-11-20

    Diffusion of information, behavioral patterns or innovations follows diverse pathways depending on a number of conditions, including the structure of the underlying social network, the sensitivity to peer pressure and the influence of media. Here we study analytically and by simulations a general model that incorporates threshold mechanism capturing sensitivity to peer pressure, the effect of "immune" nodes who never adopt, and a perpetual flow of external information. While any constant, nonzero rate of dynamically introduced spontaneous adopters leads to global spreading, the kinetics by which the asymptotic state is approached shows rich behavior. In particular, we find that, as a function of the immune node density, there is a transition from fast to slow spreading governed by entirely different mechanisms. This transition happens below the percolation threshold of network fragmentation, and has its origin in the competition between cascading behavior induced by adopters and blocking due to immune nodes. This change is accompanied by a percolation transition of the induced clusters.

  15. Kinetics of Social Contagion

    NASA Astrophysics Data System (ADS)

    Ruan, Zhongyuan; Iñiguez, Gerardo; Karsai, Márton; Kertész, János

    2015-11-01

    Diffusion of information, behavioral patterns or innovations follows diverse pathways depending on a number of conditions, including the structure of the underlying social network, the sensitivity to peer pressure and the influence of media. Here we study analytically and by simulations a general model that incorporates threshold mechanism capturing sensitivity to peer pressure, the effect of "immune" nodes who never adopt, and a perpetual flow of external information. While any constant, nonzero rate of dynamically introduced spontaneous adopters leads to global spreading, the kinetics by which the asymptotic state is approached shows rich behavior. In particular, we find that, as a function of the immune node density, there is a transition from fast to slow spreading governed by entirely different mechanisms. This transition happens below the percolation threshold of network fragmentation, and has its origin in the competition between cascading behavior induced by adopters and blocking due to immune nodes. This change is accompanied by a percolation transition of the induced clusters.

  16. Kinetics of Deliquescence

    NASA Astrophysics Data System (ADS)

    McGraw, R. L.; Lewis, E.

    2009-12-01

    We examine deliquescence phase transformation for inorganic salt particles ranging from bulk down to several nanometers in size. Thermodynamic properties of the particles, coated with aqueous solution layers of varying thickness and surrounded by vapor, are analyzed. A thin layer criterion is introduced to define a limiting deliquescence relative humidity (DRH). Nano-size particles are predicted to deliquesce at relative humidity just below the DRH on crossing a nucleation barrier, located at a critical solution layer thickness. This barrier vanishes precisely at the DRH defined by the criterion. For a population of particles, the inherent random nature of the nucleation process is predicted to result in a distribution of RH values over which deliquescence will be seen to occur. Measurement of this (apparent) non-abrupt deliquescence of the population should provide both a validation of the nucleation mechanism and a quantitative determination of nucleation rate. This paper presents calculations of crossing (i.e. deliquescence) rate using the theory of mean first passage times (MFPT). MFPT theory is shown to provide a generalization of Becker-Döring nucleation kinetics especially useful for barrier heights much lower than those typically encountered in vapor-liquid nucleation. Barrier heights for deliquescence depend on the concentration of pre-deliquesced particles and observation time, but are typically in the 5-15kT range. Calculations use the tandem nano-differential mobility analyzer setup of Biskos et al. [1] as a model framework. In their experiment, a concentration of dry salt particles is subject to a higher RH for some observation time, after which is measured the (well-separated) populations of un-deliquesced particles and those that have deliquesced. Theoretical estimates for the conversion kinetics are presented as a function of dry particle size, DRH, and salt properties. [1] G. Biskos, A. Malinowski, L. M. Russell, P. R. Buseck, and S. T. Martin

  17. Evolution of Enzyme Kinetic Mechanisms.

    PubMed

    Ulusu, Nuriye Nuray

    2015-06-01

    This review paper discusses the reciprocal kinetic behaviours of enzymes and the evolution of structure-function dichotomy. Kinetic mechanisms have evolved in response to alterations in ecological and metabolic conditions. The kinetic mechanisms of single-substrate mono-substrate enzyme reactions are easier to understand and much simpler than those of bi-bi substrate enzyme reactions. The increasing complexities of kinetic mechanisms, as well as the increasing number of enzyme subunits, can be used to shed light on the evolution of kinetic mechanisms. Enzymes with heterogeneous kinetic mechanisms attempt to achieve specific products to subsist. In many organisms, kinetic mechanisms have evolved to aid survival in response to changing environmental factors. Enzyme promiscuity is defined as adaptation to changing environmental conditions, such as the introduction of a toxin or a new carbon source. Enzyme promiscuity is defined as adaptation to changing environmental conditions, such as the introduction of a toxin or a new carbon source. Enzymes with broad substrate specificity and promiscuous properties are believed to be more evolved than single-substrate enzymes. This group of enzymes can adapt to changing environmental substrate conditions and adjust catalysing mechanisms according to the substrate's properties, and their kinetic mechanisms have evolved in response to substrate variability.

  18. Kinetic distance and kinetic maps from molecular dynamics simulation.

    PubMed

    Noé, Frank; Clementi, Cecilia

    2015-10-13

    Characterizing macromolecular kinetics from molecular dynamics (MD) simulations requires a distance metric that can distinguish slowly interconverting states. Here, we build upon diffusion map theory and define a kinetic distance metric for irreducible Markov processes that quantifies how slowly molecular conformations interconvert. The kinetic distance can be computed given a model that approximates the eigenvalues and eigenvectors (reaction coordinates) of the MD Markov operator. Here, we employ the time-lagged independent component analysis (TICA). The TICA components can be scaled to provide a kinetic map in which the Euclidean distance corresponds to the kinetic distance. As a result, the question of how many TICA dimensions should be kept in a dimensionality reduction approach becomes obsolete, and one parameter less needs to be specified in the kinetic model construction. We demonstrate the approach using TICA and Markov state model (MSM) analyses for illustrative models, protein conformation dynamics in bovine pancreatic trypsin inhibitor and protein-inhibitor association in trypsin and benzamidine. We find that the total kinetic variance (TKV) is an excellent indicator of model quality and can be used to rank different input feature sets.

  19. Kinetic Transport in Crystals

    NASA Astrophysics Data System (ADS)

    Marklof, Jens

    2010-03-01

    One of the central challenges in kinetic theory is the derivation of macroscopic evolution equations--describing, for example, the dynamics of an electron gas--from the underlying fundamental microscopic laws of classical or quantum mechanics. An iconic mathematical model in this research area is the Lorentz gas, which describes an ensemble of non-interacting point particles in an infinite array of spherical scatterers. In the case of a disordered scatterer configuration, the classical results by Gallavotti, Spohn and Boldrighini-Bunimovich-Sinai show that the time evolution of a macroscopic particle cloud is governed, in the limit of small scatterer density (Boltzmann-Grad limit), by the linear Boltzmann equation. In this lecture I will discuss the recent discovery that for a periodic configuration of scatterers the linear Boltzmann equation fails, and the random flight process that emerges in the Boltzmann-Grad limit is substantially more complicated. The key ingredient in the description of the limiting stochastic process is the renormalization dynamics on the space of lattices, a powerful technique that has recently been successfully applied also to other open problems in mathematical physics, including KAM theory and quantum chaos. This lecture is based on joint work with Andreas Strömbergsson, Uppsala.

  20. Chemical Looping Combustion Kinetics

    SciTech Connect

    Edward Eyring; Gabor Konya

    2009-03-31

    One of the most promising methods of capturing CO{sub 2} emitted by coal-fired power plants for subsequent sequestration is chemical looping combustion (CLC). A powdered metal oxide such as NiO transfers oxygen directly to a fuel in a fuel reactor at high temperatures with no air present. Heat, water, and CO{sub 2} are released, and after H{sub 2}O condensation the CO{sub 2} (undiluted by N{sub 2}) is ready for sequestration, whereas the nickel metal is ready for reoxidation in the air reactor. In principle, these processes can be repeated endlessly with the original nickel metal/nickel oxide participating in a loop that admits fuel and rejects ash, heat, and water. Our project accumulated kinetic rate data at high temperatures and elevated pressures for the metal oxide reduction step and for the metal reoxidation step. These data will be used in computational modeling of CLC on the laboratory scale and presumably later on the plant scale. The oxygen carrier on which the research at Utah is focused is CuO/Cu{sub 2}O rather than nickel oxide because the copper system lends itself to use with solid fuels in an alternative to CLC called 'chemical looping with oxygen uncoupling' (CLOU).

  1. Kinetics of dibenzothiophene hydrodesulfurization

    SciTech Connect

    Ho, T.C.; Sobel, J.E. )

    1991-04-01

    Hydrotreating is a process in which organically bound sulfur and nitrogen compounds are removed from petroleum feedstocks to produce processible, stable, and environmentally acceptable liquid fuels or lubes. Essentially two types of catalysts, which differ in composition, are in use in current refineries: one is sulfided CoO-MoO{sub 3}/{gamma}-Al{sub 2}O{sub 3}, the other sulfided NiO-MoO{sub 3}/Al{sub 2}O{sub 3}. The selection of these catalysts depends largely on the processing objectives and the nature of the feedstocks. Generally speaking, the NiMo catalysts are used for hydrodenitrogenation (HDN) and hydrodearomatization (HDA), while the CoMo catalysts are used for hydrodesulfurization (HDS). HDS of dibenzothiophene (DBT) is a useful model reaction for HDS of commercial middle distillate feedstocks. In a previous study, Ho et al. quantified the interactions between HDN and HDA on a commercial NiMo catalyst by using a feed mixture containing 2,4-dimethyl pyridine and 2-methylnaphthalene. With the same catalyst, here we determine the kinetics of DBT HDS. Another reason for undertaking the present study is that relatively little attention has been paid to DBT HDS on NiMo catalysts. Most published DBT HDS studies have been done on CoMo catalysts.

  2. Kinetic assembly of coordination networks.

    PubMed

    Ohtsu, Hiroyoshi; Kawano, Masaki

    2017-08-03

    Kinetic assembly is an important method for obtaining desired materials in chemical synthesis and materials science. We highlight the kinetic assembly of porous coordination networks, which promote the production of interactive pore sites. The interactive pore sites can activate or stabilize guest molecules. The properties of interactive pores are typified by iodine chemisorption and small sulfur encapsulation. Using interactive pores, we trapped small sulfur allotropes, such as S2, cyclo-S3, bent-S3, and S6, demonstrating the importance of interactive pore sites. Here, we address the important aspects of interactive pore sites created by kinetic assembly of porous coordination networks.

  3. On the relationships between Michaelis-Menten kinetics, reverse Michaelis-Menten kinetics, Equilibrium Chemistry Approximation kinetics and quadratic kinetics

    NASA Astrophysics Data System (ADS)

    Tang, J. Y.

    2015-09-01

    The Michaelis-Menten kinetics and the reverse Michaelis-Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use which of the two are often ambiguous. Here I show that these two kinetics are special approximations to the Equilibrium Chemistry Approximation kinetics, which is the first order approximation to the quadratic kinetics that solves the equation of enzyme-substrate complex exactly for a single enzyme single substrate biogeochemical reaction with the law of mass action and the assumption of quasi-steady-state for the enzyme-substrate complex and that the product genesis from enzyme-substrate complex is much slower than the equilibration between enzyme-substrate complexes, substrates and enzymes. In particular, I showed that the derivation of the Michaelis-Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis-Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in the Equilibrium Chemistry Approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis-Menten kinetics was found to persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln [ E ]T of v with respect the total enzyme concentration [ E ]T and persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln [ S ]T of v with respect to the total substrate concentration [ S ]T. Meanwhile

  4. On the relationships between Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, Equilibrium Chemistry Approximation kinetics and quadratic kinetics

    DOE PAGES

    Tang, J. Y.

    2015-09-03

    The Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use which of the two are often ambiguous. Here I show that these two kinetics are special approximations to the Equilibrium Chemistry Approximation kinetics, which is the first order approximation to the quadratic kinetics that solves the equation of enzyme-substrate complex exactly for a single enzyme single substrate biogeochemical reaction with the law of mass action and the assumption of quasi-steady-state formore » the enzyme-substrate complex and that the product genesis from enzyme-substrate complex is much slower than the equilibration between enzyme-substrate complexes, substrates and enzymes. In particular, I showed that the derivation of the Michaelis–Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis–Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in the Equilibrium Chemistry Approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis–Menten kinetics was found to persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln [ E ]T of v with respect the total enzyme concentration [ E ]T and persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln [ S ]T of v with respect to the total substrate concentration [ S ]T. Meanwhile, the

  5. Cellulose thermal decomposition kinetics: Global mass loss kinetics

    SciTech Connect

    Milosavljevic, I.; Suuberg, E.M.

    1995-04-01

    The kinetics of cellulose pyrolysis have received considerable attention during the past few decades. Despite intensive study, there remains controversy in the literature even on a topic as basic as the global kinetics of pyrolysis. The reported kinetics have been reconsidered in light of new experimental results that suggest a simple resolution to that part of the controversy concerning the activation energy of pyrolysis. It appears that the reported kinetics are sensitive to the heating rate employed in the experiments used to deduce them. Experiments in which the cellulose is rapidly heated to above 600 K give apparently ``low`` activation energies, mainly between about 140 and 155 kJ/mol, in the case of the material studied here. This applies to both ``isothermal`` and high heating rate temperature-ramp experiments. Alternatively, cellulose heated more slowly to temperatures below 600 K appears to lose mass with an activation energy that is about 218 kJ/mol, The mathematical modeling of processes involving pyrolysis of cellulosic materials (e.g., biomass conversion processes, fire phenomena) can be strongly influenced by which kinetics are assumed, since the kinetic constants from one regime will not accurately predict mass loss in the other.

  6. Co2(nu2)-o Quenching Rate Coefficient Derived from Coincidental SABER-TIMED and Fort Collins Lidar Observations of the Mesosphere and Lower Thermosphere

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Kutepov, A. A.; She, C.-Y.; Smith, A. K.; Pesnell, W. D.; Goldberg, R. A.

    2012-01-01

    Among the processes governing the energy balance in the mesosphere and lower thermosphere (MLT), the quenching of CO2(nu2) vibrational levels by collisions with O atoms plays an important role. However, there is a factor of 3-4 discrepancy between the laboratory measurements of the CO2-O quenching rate coefficient, k(sub VT),and its value estimated from the atmospheric observations. In this study, we retrieve k(sub VT) in the altitude region85-105 km from the coincident SABER/TIMED and Fort Collins sodium lidar observations by minimizing the difference between measured and simulated broadband limb 15 micron radiation. The averaged k(sub VT) value obtained in this work is 6.5 +/- 1.5 X 10(exp -12) cubic cm/s that is close to other estimates of this coefficient from the atmospheric observations.However, the retrieved k(sub VT) also shows altitude dependence and varies from 5.5 1 +/-1 10(exp -12) cubic cm/s at 90 km to 7.9 +/- 1.2 10(exp -12) cubic cm/s at 105 km. Obtained results demonstrate the deficiency in current non-LTE modeling of the atmospheric 15 micron radiation, based on the application of the CO2-O quenching and excitation rates, which are linked by the detailed balance relation. We discuss the possible model improvements, among them accounting for the interaction of the non-thermal oxygen atoms with CO2 molecules.

  7. Modelling Heart Rate Kinetics

    PubMed Central

    Zakynthinaki, Maria S.

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual’s cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  8. Degradation Kinetics of VX

    SciTech Connect

    Gary S. Groenewold

    2010-12-01

    O-ethyl S-(2-diisopropylaminoethyl)phosphonothiolate (VX) is the most toxic of the conventional chemical warfare agents. It is a persistent compound, an attribute derived from its relative involatility and slow rates of hydrolysis. These properties suggest that VX can linger in an exposed environment for extended periods of time long after the air has cleared. Concern over prolonged risk from VX exposure is exacerbated by the fact that it poses a dermal contact hazard. Hence a detailed understanding of volatilization rates, and degradation pathways and rates occurring in various environments is needed. Historically, volatilization has not been considered to be an important mechanism for VX depletion, but recent studies have shown that a significant fraction of VX may volatilize, depending on the matrix. A significant body of research has been conducted over the years to unravel VX degradation reaction pathways and to quantify the rates at which they proceed. Rigorous measurement of degradation rates is frequently difficult, and thus in many cases the degradation of VX has been described in terms of half lives, while in fewer instances rate constants have been measured. This variable approach to describing degradation kinetics reflects uncertainty regarding the exact nature of the degradation mechanisms. In this review, rates of VX degradation are compared on the basis of pseudo-first order rate constants, in order to provide a basis for assessing likelihood of VX persistence in a given environment. An issue of specific concern is that one VX degradation pathway produces S-2-(diisopropylaminoethyl) methylphosphonothioic acid (known as EA2192), which is a degradation product that retains much of the original toxicity of VX. Consequently degradation pathways and rates for EA2192 are also discussed.

  9. Modelling heart rate kinetics.

    PubMed

    Zakynthinaki, Maria S

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual's cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women).

  10. Kinetic Equations for Economic Sciences

    NASA Astrophysics Data System (ADS)

    Bisi, M.; Brugna, C.

    2010-04-01

    We discuss, both from the analytical and the numerical point of view, a kinetic model for wealth distribution in a simple market economy which models, besides binary trade interactions, also taxation and redistribution of collected wealth.

  11. Kinetic Magnetorotational Turbulence and Dynamo

    NASA Astrophysics Data System (ADS)

    Kunz, Matthew; Stone, James; Quataert, Eliot

    2016-10-01

    Low-luminosity black-hole accretion flows, such as that at the Galactic center, are collisionless. A kinetic approach is thus necessary to understand the transport of heat and angular momentum, the acceleration of particles, and the growth and structure of the magnetic field in these systems. We present results from the first 6D kinetic numerical simulation of magnetorotational turbulence and dynamo, using the local shearing-box model. Special attention will be paid to the enhanced transport of angular momentum by field-aligned pressure anisotropies, as well as to the ion-Larmor-scale kinetic instabilities (firehose, mirror, ion-cyclotron) which regulate those anisotropies. Energy spectra and phase-space evolution will be discussed. Time permitting, dedicated nonlinear studies of firehose and mirror instabilities in a shearing plasma will also be presented as a complement to the study of the magnetorotational instability. The profits, perils, and price of using a kinetic approach will be briefly mentioned.

  12. Chemical kinetics of geminal recombination

    SciTech Connect

    Levin, P.P.; Khudyakov, I.V.; Brin, E.F.; Kuz'min, V.A.

    1988-09-01

    The kinetics of geminal recombination of triplet radical pairs formed in photoreduction of benzophenone by p-cresol in glycerin solution was studied by pulsed laser photolysis. The experiments were conducted at several temperatures and in a constant magnetic field of H = 0.34 T. The parameters in six kinetic equations describing geminal recombination were determined with a computer. The values of the sums of the squares of the residual deviations of the approximation were obtained. It was found that the kinetics are best described by the functions proposed by Noyes and Shushin. It was shown that it is necessary to use the mutual diffusion coefficient of the radicals, which is significantly smaller than the sum of the estimations of the experimental values of the radical diffusion coefficients, for describing the kinetics due to the correlations of the molecular motions of the radicals in the cage.

  13. Kinetic parameters from thermogravimetric analysis

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard L.

    1993-01-01

    High performance polymeric materials are finding increased use in aerospace applications. Proposed high speed aircraft will require materials to withstand high temperatures in an oxidative atmosphere for long periods of time. It is essential that accurate estimates be made of the performance of these materials at the given conditions of temperature and time. Temperatures of 350 F (177 C) and times of 60,000 to 100,000 hours are anticipated. In order to survey a large number of high performance polymeric materials on a reasonable time scale, some form of accelerated testing must be performed. A knowledge of the rate of a process can be used to predict the lifetime of that process. Thermogravimetric analysis (TGA) has frequently been used to determine kinetic information for degradation reactions in polymeric materials. Flynn and Wall studied a number of methods for using TGA experiments to determine kinetic information in polymer reactions. Kinetic parameters, such as the apparent activation energy and the frequency factor, can be determined in such experiments. Recently, researchers at the McDonnell Douglas Research Laboratory suggested that a graph of the logarithm of the frequency factor against the apparent activation energy can be used to predict long-term thermo-oxidative stability for polymeric materials. Such a graph has been called a kinetic map. In this study, thermogravimetric analyses were performed in air to study the thermo-oxidative degradation of several high performance polymers and to plot their kinetic parameters on a kinetic map.

  14. Elemental sulfur coarsening kinetics.

    PubMed

    Garcia, Angel A; Druschel, Gregory K

    mechanism of coarsening. Elemental sulfur sols coarsen rapidly at elevated temperatures and experience significant effects on both solubility and particle coarsening kinetics due to interaction with surfactants. Growth of elemental sulfur nanoparticles and sols is largely governed by Ostwald ripening processes.

  15. A Kinetic-fluid Model

    SciTech Connect

    First Author = C.Z. Cheng; Jay R. Johnson

    1998-07-10

    A nonlinear kinetic-fluid model for high-beta plasmas with multiple ion species which can be applied to multiscale phenomena is presented. The model embeds important kinetic effects due to finite ion Larmor radius (FLR), wave-particle resonances, magnetic particle trapping, etc. in the framework of simple fluid descriptions. When further restricting to low frequency phenomena with frequencies less than the ion cyclotron frequency the kinetic-fluid model takes a simpler form in which the fluid equations of multiple ion species collapse into single-fluid density and momentum equations and a low frequency generalized Ohm's law. The kinetic effects are introduced via plasma pressure tensors for ions and electrons which are computed from particle distribution functions that are governed by the Vlasov equation or simplified plasma dynamics equations such as the gyrokinetic equation. The ion FLR effects provide a finite parallel electric field, a perpendicular velocity that modifies the ExB drift, and a gyroviscosity tensor, all of which are neglected in the usual one-fluid MHD description. Eigenmode equations are derived which include magnetosphere-ionosphere coupling effects for low frequency waves (e.g., kinetic/inertial Alfven waves and ballooning-mirror instabilities).

  16. CO2(v2)-O Quenching Rate Coefficient Derived From Coincidental SABER/TIMED And Ground-Based Lidar Observations Of The Mesosphere And Lower Thermosphere

    NASA Astrophysics Data System (ADS)

    Feofilov, A.; Kutepov, A.; Chu, X.; Smith, A. K.

    2012-12-01

    Infrared emission in 15 μm CO2 band (I15 μm) is the dominant cooling mechanism in the Earth's mesosphere and lower thermosphere (MLT). On Earth, the magnitude of the MLT cooling affects both the mesopause temperature and height; the stronger the cooling, the colder and higher is the mesopause. This process is also important for the energy budgets of Martian and, especially, Venusian atmospheres, where CO2 cooling compensates for the EUV heating of the dayside upper atmosphere. The I15 μm radiation is used to retrieve vertical temperature distributions T(z) in Earth's atmosphere by a number of satellite instruments. Both the cooling efficiency and I15 μm strongly depend on the rate coefficient of the quenching of the CO2(ν2) vibrational levels by collisions with oxygen atoms. However, there is a factor of 3-4 discrepancy between the laboratory measurements of this rate coefficient, kVT, and its value estimated from the atmospheric observations. In this study, we retrieve kVT in the altitude region 85-105 km from the coincident SABER/TIMED and ground-based lidar observations in different locations by minimizing the difference between measured and simulated broadband limb 15 μm radiation. Obtained results demonstrate the deficiency in current non-LTE modeling of the atmospheric 15 μm radiation, based on the application of the CO2-O quenching and excitation rates, which are linked by the detailed balance relation. We discuss the possible model improvements, among them accounting for the interaction of the "non-thermal" oxygen atoms with CO2 molecules.

  17. Thermal oxidation kinetics of germanium

    NASA Astrophysics Data System (ADS)

    Wang, X.; Nishimura, T.; Yajima, T.; Toriumi, A.

    2017-07-01

    Thermal oxidation kinetics of Ge was investigated by the 18O tracing study and re-oxidation experiments of the SiO2/GeO2 stacked oxide-layer. The results suggest that Ge oxidation kinetics is completely different from that expected from the Deal-Grove model and that Ge is oxidized by GeO2 on Ge instead of O2 at the interface. This oxidation process forms large amounts of oxygen vacancies in GeO2, which facilitate the diffusion of oxygen atoms in GeO2. This means that oxygen atoms diffuse through GeO2 with an exchange type of process. Based on experimental results, a possible kinetics for Ge oxidation is discussed.

  18. Kinetic model of network traffic

    NASA Astrophysics Data System (ADS)

    Antoniou, I.; Ivanov, V. V.; Kalinovsky, Yu. L.

    2002-05-01

    We present the first results on the application of the Prigogine-Herman kinetic approach (Kinetic Theory of Vehicular Traffic, American Elsevier Publishing Company, Inc., New York, 1971) to the network traffic. We discuss the solution of the kinetic equation for homogeneous time-independent situations and for the desired speed distribution function, obtained from traffic measurements analysis. For the log-normal desired speed distribution function the solution clearly shows two modes corresponding to individual flow patterns (low-concentration mode) and to collective flow patterns (traffic jam mode). For low-concentration situations we found almost linear dependence of the information flow versus the concentration and that the higher the average speed the lower the concentration at which the optimum flow takes place. When approaching the critical concentration there are no essential differences in the flow for different desired average speeds, whereas for the individual flow regions there are dramatic differences.

  19. Kinetic study on biomass gasification

    SciTech Connect

    Bingyan, X.; Chuangzhi, W.; Zhengfen, L.; Guang, Z.X. )

    1992-09-01

    An experimental apparatus, with the features of fast heating rate and continuous record of reaction parameters, was developed to study kinetics of fast pyrolysis. The temperature effects, at a range of 400 C to 900 C, on pyrolysis rate, products profile, gas quality and quantity, and so on, were studied and the results are listed and analyzed. The effect of secondary reaction of gas phase at 700 C was tested and the regression result is expressed in an experimental formula. Based on the experimental results, the three-stage-reaction mechanism module is suggested. The kinetic expression to calculate gas formation rate is concluded as: d{alpha}/dt = A exp({minus}E/RT)(1 {minus} {alpha}){sup n}. The kinetic parameters of A, E, and n at different temperatures are given in the paper.

  20. Stochastic kinetic mean field model

    NASA Astrophysics Data System (ADS)

    Erdélyi, Zoltán; Pasichnyy, Mykola; Bezpalchuk, Volodymyr; Tomán, János J.; Gajdics, Bence; Gusak, Andriy M.

    2016-07-01

    This paper introduces a new model for calculating the change in time of three-dimensional atomic configurations. The model is based on the kinetic mean field (KMF) approach, however we have transformed that model into a stochastic approach by introducing dynamic Langevin noise. The result is a stochastic kinetic mean field model (SKMF) which produces results similar to the lattice kinetic Monte Carlo (KMC). SKMF is, however, far more cost-effective and easier to implement the algorithm (open source program code is provided on http://skmf.eu website). We will show that the result of one SKMF run may correspond to the average of several KMC runs. The number of KMC runs is inversely proportional to the amplitude square of the noise in SKMF. This makes SKMF an ideal tool also for statistical purposes.

  1. Kinetic Modeling of Divertor Plasma

    NASA Astrophysics Data System (ADS)

    Ishiguro, Seiji; Hasegawa, Hiroki; Pianpanit, Theerasarn

    2015-11-01

    Particle-in-Cell (PIC) simulation with the Monte Carlo collisions and the cumulative scattering angle coulomb collision can present kinetic dynamics of divertor plasmas. We are developing two types of PIC codes. The first one is the three dimensional bounded PIC code where three dimensional kinetic dynamics of blob is studied and current flow structures related to sheath formation are unveiled. The second one is the one spatial three velocity space dimensional (1D3V) PIC code with the Monte Carlo collisions where formation of detach plasma is studied. First target of our research is to construct self-consistent full kinetic simulation modeling of the linear divertor simulation experiments. This work is performed with the support and under the auspices of NIFS Collaboration Research program (NIFS15KNSS059, NIFS14KNXN279, and NIFS13KNSS038) and the Research Cooperation Program on Hierarchy and Holism in Natural Science at NINS.

  2. Kinetic Measurements for Enzyme Immobilization.

    PubMed

    Cooney, Michael J

    2017-01-01

    Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of this enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten were advancing their work by studying the kinetics of an enzyme saccharase which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis and ever since the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, and selectivity towards nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adapted to the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V max, K M) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.

  3. Kinetic measurements for enzyme immobilization.

    PubMed

    Cooney, Michael J

    2011-01-01

    Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of the enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten had advanced this work by studying the kinetics of the enzyme saccharase, which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis, and ever since, the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, selectivity toward nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adopted for the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V(max), K(M)) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review, enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.

  4. Chemical kinetics and combustion modeling

    SciTech Connect

    Miller, J.A.

    1993-12-01

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  5. Chemical Kinetics Laboratory Discussion Worksheet.

    PubMed

    Demoin, Dustin Wayne; Jurisson, Silvia S

    2013-09-10

    A laboratory discussion worksheet and its answer key provide instructors and students a discussion model to further the students' understanding of chemical kinetics. This discussion worksheet includes a section for students to augment their previous knowledge about chemical kinetics measurements, an initial check on students' understanding of basic concepts, a group participation model where students work on solving complex-conceptual problems, and a conclusion to help students connect this discussion to their laboratory or lecture class. Additionally, the worksheet has a detailed solution to a more advanced problem to help students understand how the concepts they have put together relate to problems they will encounter during later formal assessments.

  6. Chemical Kinetics Laboratory Discussion Worksheet

    PubMed Central

    Demoin, Dustin Wayne; Jurisson, Silvia S.

    2013-01-01

    A laboratory discussion worksheet and its answer key provide instructors and students a discussion model to further the students’ understanding of chemical kinetics. This discussion worksheet includes a section for students to augment their previous knowledge about chemical kinetics measurements, an initial check on students’ understanding of basic concepts, a group participation model where students work on solving complex-conceptual problems, and a conclusion to help students connect this discussion to their laboratory or lecture class. Additionally, the worksheet has a detailed solution to a more advanced problem to help students understand how the concepts they have put together relate to problems they will encounter during later formal assessments. PMID:24092948

  7. Mass Conservation and Chemical Kinetics.

    ERIC Educational Resources Information Center

    Barbara, Thomas M.; Corio, P. L.

    1980-01-01

    Presents a method for obtaining all mass conservation conditions implied by a given mechanism in which the conditions are used to simplify integration of the rate equations and to derive stoichiometric relations. Discusses possibilities of faulty inference of kinetic information from a given stoichiometry. (CS)

  8. Kinetic Modeling of Biological Systems

    PubMed Central

    Petzold, Linda; Pettigrew, Michel F.

    2010-01-01

    The dynamics of how the constituent components of a natural system interact defines the spatio-temporal response of the system to stimuli. Modeling the kinetics of the processes that represent a biophysical system has long been pursued with the aim of improving our understanding of the studied system. Due to the unique properties of biological systems, in addition to the usual difficulties faced in modeling the dynamics of physical or chemical systems, biological simulations encounter difficulties that result from intrinsic multiscale and stochastic nature of the biological processes. This chapter discusses the implications for simulation of models involving interacting species with very low copy numbers, which often occur in biological systems and give rise to significant relative fluctuations. The conditions necessitating the use of stochastic kinetic simulation methods and the mathematical foundations of the stochastic simulation algorithms are presented. How the well-organized structural hierarchies often seen in biological systems can lead to multiscale problems, and possible ways to address the encountered computational difficulties are discussed. We present the details of the existing kinetic simulation methods, and discuss their strengths and shortcomings. A list of the publicly available kinetic simulation tools and our reflections for future prospects are also provided. PMID:19381542

  9. Solving Simple Kinetics without Integrals

    ERIC Educational Resources Information Center

    de la Pen~a, Lisandro Herna´ndez

    2016-01-01

    The solution of simple kinetic equations is analyzed without referencing any topic from differential equations or integral calculus. Guided by the physical meaning of the rate equation, a systematic procedure is used to generate an approximate solution that converges uniformly to the exact solution in the case of zero, first, and second order…

  10. Disco Dancing and Kinetic Theory

    ERIC Educational Resources Information Center

    Karakas, Mehmet

    2010-01-01

    This paper provides an example of an innovative science activity used in a science methods course for future elementary teachers at a small university in northeastern Turkey. The activity aims to help prospective elementary teachers understand kinetic-molecular theory in a simple way and to expose these preservice teachers to an innovative…

  11. Surfactant adsorption kinetics in microfluidics

    PubMed Central

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-01-01

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore–surfactant interactions. PMID:27688765

  12. Solving Simple Kinetics without Integrals

    ERIC Educational Resources Information Center

    de la Pen~a, Lisandro Herna´ndez

    2016-01-01

    The solution of simple kinetic equations is analyzed without referencing any topic from differential equations or integral calculus. Guided by the physical meaning of the rate equation, a systematic procedure is used to generate an approximate solution that converges uniformly to the exact solution in the case of zero, first, and second order…

  13. Kinetic Modeling of Biological Systems

    SciTech Connect

    Resat, Haluk; Petzold, Linda; Pettigrew, Michel F.

    2009-04-21

    The dynamics of how its constituent components interact define the spatio-temporal response of a natural system to stimuli. Modeling the kinetics of the processes that represent a biophysical system has long been pursued with the aim of improving our understanding of the studied system. Due to the unique properties of biological systems, in addition to the usual difficulties faced in modeling the dynamics of physical or chemical systems, biological simulations encounter difficulties that result from intrinsic multiscale and stochastic nature of the biological processes. This chapter discusses the implications for simulation of models involving interacting species with very low copy numbers, which often occur in biological systems and give rise to significant relative fluctuations. The conditions necessitating the use of stochastic kinetic simulation methods and the mathematical foundations of the stochastic simulation algorithms are presented. How the well-organized structural hierarchies often seen in biological systems can lead to multiscale problems, and possible ways to address the encountered computational difficulties are discussed. We present the details of the existing kinetic simulation methods, and discuss their strengths and shortcomings. A list of the publicly available kinetic simulation tools and our reflections for future prospects are also provided.

  14. Deuterium Exchange Kinetics by NMR.

    ERIC Educational Resources Information Center

    Roper, G. C.

    1985-01-01

    Describes a physical chemistry experiment which allows such concepts as kinetics, catalysis, isotope shifts, coupling constants, and the use of nuclear magnetic resonance (NMR) for quantitative work to be covered in the same exercise. Background information, experimental procedures used, and typical results obtained are included. (JN)

  15. Dehydration kinetics of neotame monohydrate.

    PubMed

    Dong, Zedong; Salsbury, Jonathon S; Zhou, Deliang; Munson, Eric J; Schroeder, Steve A; Prakash, Indra; Vyazovkin, Sergey; Wight, Charles A; Grant, David J W

    2002-06-01

    The dehydration of neotame monohydrate was monitored at various temperatures by differential scanning calorimetry (DSC), thermogravimetry (TGA), hot-stage microscopy (HSM), powder X-ray diffractometry (PXRD), and (13)C solid-state nuclear magnetic resonance (SSNMR) spectroscopy. This work emphasizes kinetic analysis of isothermal TGA data by fitting to various solid-state reaction models and by model-free kinetic treatment. The dehydration of neotame monohydrate follows the kinetics of a two-dimensional phase boundary reaction (R2) at 40-50 degrees C with an activation energy of 75 +/- 9 kJ/mol, agreeing well with 60-80 kJ/mol from model-free kinetics. At a low heating rate in DSC and TGA, neotame monohydrate undergoes dehydration to produce anhydrate Form E, which then converts to anhydrate Form A, followed by the melting of A. Neotame monohydrate under dry nitrogen purge at 50 mL/min undergoes partial isothermal dehydration at 50 degrees C to produce neotame anhydrate Form A. When neotame monohydrate is heated very slowly from 50 to 65-70 degrees C over 24 h, pure Form A is obtained. Copyright 2002 Wiley-Liss, Inc.

  16. Disco Dancing and Kinetic Theory

    ERIC Educational Resources Information Center

    Karakas, Mehmet

    2010-01-01

    This paper provides an example of an innovative science activity used in a science methods course for future elementary teachers at a small university in northeastern Turkey. The activity aims to help prospective elementary teachers understand kinetic-molecular theory in a simple way and to expose these preservice teachers to an innovative…

  17. Deuterium Exchange Kinetics by NMR.

    ERIC Educational Resources Information Center

    Roper, G. C.

    1985-01-01

    Describes a physical chemistry experiment which allows such concepts as kinetics, catalysis, isotope shifts, coupling constants, and the use of nuclear magnetic resonance (NMR) for quantitative work to be covered in the same exercise. Background information, experimental procedures used, and typical results obtained are included. (JN)

  18. Mass Conservation and Chemical Kinetics.

    ERIC Educational Resources Information Center

    Barbara, Thomas M.; Corio, P. L.

    1980-01-01

    Presents a method for obtaining all mass conservation conditions implied by a given mechanism in which the conditions are used to simplify integration of the rate equations and to derive stoichiometric relations. Discusses possibilities of faulty inference of kinetic information from a given stoichiometry. (CS)

  19. Surfactant adsorption kinetics in microfluidics.

    PubMed

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-10-11

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than [Formula: see text] to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning-here through ion exchange-unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore-surfactant interactions.

  20. Surfactant adsorption kinetics in microfluidics

    NASA Astrophysics Data System (ADS)

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-10-01

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore-surfactant interactions.

  1. Kinetic energy equations for the average-passage equation system

    NASA Technical Reports Server (NTRS)

    Johnson, Richard W.; Adamczyk, John J.

    1989-01-01

    Important kinetic energy equations derived from the average-passage equation sets are documented, with a view to their interrelationships. These kinetic equations may be used for closing the average-passage equations. The turbulent kinetic energy transport equation used is formed by subtracting the mean kinetic energy equation from the averaged total instantaneous kinetic energy equation. The aperiodic kinetic energy equation, averaged steady kinetic energy equation, averaged unsteady kinetic energy equation, and periodic kinetic energy equation, are also treated.

  2. Dissemination of developed in VNIIOFI high temperature Fix-points based on Metal-Carbon Eutectics for Space Applications of ultra-precise Radiometry and Spectral Radiation Thermometry Measurements

    NASA Astrophysics Data System (ADS)

    Sapritsky, V.; Ogarev, S.; Khlevnoy, B.

    Several fixed-point cells (with 2 and 4 mm apertures for spectral-radiance application, and with 8 and 10 mm apertures (for the spectral irradiance measurements) have been designed and investigated at VNIIOFI consisted of a high- purity graphite crucibles containing Re-C ingots with nominal total impurity levels of 5,5N at the eutectic composition(s). It was investigated that fix-point reproducibility (freezing plateau level for all measured cells) was up to 0.01...0.02% between series of measurements / crucibles, and 0.002...0.004% within a sample measurement session, i.e. better than 100 mK. Measurements of high-temperature fixed points blackbodies based on Ir-C and Re-C eutectics were carried out to investigate their applicability as radiation sources for precision photometry and radiometry, in particular for astronomy and space applications, like long-term measurements of solar variability, etc. The measurement results encourage that the utilization of a new series of a high-temperature fix-point sources hand in hand with cryo-radiometer detector could cardinally change the situation in reproduction of spectral radiance, irradiance and temperature international scales. Several more high-temperature eutectics (e.g. TiC-C metal- carbon eutectics with T = 3057 C) are being investigated further for use as high- temperature fixed-point radiance and irradiance sources in o der to increase ther accuracy of radiometric and radiance-temperature scales above the conventionally assigned values of temperatures of ITS-90.

  3. Kinetic investigation of wood pyrolysis

    SciTech Connect

    Thurner, F.; Mann, U.; Beck, S. R.

    1980-06-01

    The objective of this investigation was to determine the kinetics of the primary reactions of wood pyrolysis. A new experimental method was developed which enabled us to measure the rate of gas, tar, and char production while taking into account the temperature variations during the wood heating up. The experimental method developed did not require any sophisticated instruments. It facilitated the collection of gas, tar and residue (unreacted wood and char) as well as accurate measurement of the temperature inside the wood sample. Expressions relating the kinetic parameters to the measured variables were derived. The pyrolysis kinetics was investigated in the range of 300 to 400/sup 0/C at atmospheric pressure and under nitrogen atmosphere. Reaction temperature and mass fractions of gas, tar, and residue were measured as a function of time. Assuming first-order reactions, the kinetic parameters were determined using differential method. The measured activation energies of wood pyrolysis to gas, tar, and char were 88.6, 112.7, and 106.5 kJ/mole, respectively. These kinetic data were then used to predict the yield of the various pyrolysis products. It was found that the best prediction was obtained when an integral-mean temperature obtained from the temperature-time curve was used as reaction temperature. The pyrolysis products were analyzed to investigate the influence of the pyrolysis conditions on the composition. The gas consisted mainly of carbon dioxide, carbon monoxide, oxygen, and C/sub 3//sup +/-compounds. The gas composition depended on reaction time as well as reactor temperature. The tar analysis indicated that the tar consisted of about seven compounds. Its major compound was believed to be levoglucosan. Elemental analysis for the char showed that the carbon content increased with increasing temperature.

  4. Kinetics and photochemistry Golden, D. M.

    NASA Technical Reports Server (NTRS)

    Demore, W. B.; Golden, R. F.; Howard, C. J.; Kurylo, M. J.; Margitan, J. J.; Molina, M. J.; Ravishankara, A. R.; Watson, R. T.; Hampson, R. F.

    1985-01-01

    The data for chemical kinetics rate constants and photochemical cross sections taken from a compilation prepared in early 1985, entitled Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling, is presented.

  5. Ozone-Temperature Diurnal and Longer Term Correlations, in the Lower Thermosphere, Mesosphere and Stratosphere, Based on Measurements from SABER on TIMED

    NASA Technical Reports Server (NTRS)

    Huang, Frank T.; Mayr, Hans G.; Russell, James M., III; Mlynczak, Martin G.

    2012-01-01

    The analysis of mutual ozone-temperature variations can provide useful information on their interdependencies relative to the photochemistry and dynamics governing their behavior. Previous studies have mostly been based on satellite measurements taken at a fixed local time in the stratosphere and lower mesosphere. For these data, it is shown that the zonal mean ozone amounts and temperatures in the lower stratosphere are mostly positively correlated, while they are mostly negatively correlated in the upper stratosphere and in the lower mesosphere. The negative correlation, due to the dependence of photochemical reaction rates on temperature, indicates that ozone photochemistry is more important than dynamics in determining the ozone amounts. In this study, we provide new results by extending the analysis to include diurnal variations over 24 hrs of local time, and to larger spatial regimes, to include the upper mesosphere and lower thermosphere (MLT). The results are based on measurements by the SABER instrument on the TIMED satellite. For mean variations (i.e., averages over local time and longitude) in the MLT, our results show that there is a sharp reversal in the correlation near 80 km altitude, above which the ozone mixing ratio and temperature are mostly positively correlated, while they are mostly negatively correlated below 80 km. This is consistent with the view that above -80 km, effects due to dynamics are more important compared to photochemistry. For diurnal variations, both the ozone and temperature show phase progressions in local time, as a function of altitude and latitude. For temperature, the phase progression is as expected, as they represent migrating tides. For day time ozone, we also find regular phase progression in local time over the whole altitude range of our analysis, 25 to 105 km, at least for low latitudes. This was not previously known, although phase progressions had been noted by us and by others at lower altitudes. For diurnal

  6. Global normal mode planetary wave activity: a study using TIMED/SABER observations from the stratosphere to the mesosphere-lower thermosphere

    NASA Astrophysics Data System (ADS)

    John, Sherine Rachel; Kumar, Karanam Kishore

    2016-12-01

    A comprehensive study of three normal mode travelling planetary waves, namely the quasi-16, -10 and -5 day waves, is carried out globally using 5 years (2003-2007) of TIMED/SABER temperature measurements from the stratosphere to the mesosphere-lower thermosphere (MLT) by employing the two dimensional Fourier decomposition technique. From preliminary analysis, it is found that significant amplitudes of normal modes are confined to wave numbers-2 (westward propagating modes) to 2 (eastward propagating modes). The westward propagating quasi 16-day waves with zonal wave number 1 (W1; W1 refers to westward propagating wave with zonal wave number 1) peaks over winter-hemispheric high latitudes with northern hemisphere (NH) having higher amplitudes as compared to their southern hemispheric (SH) counterpart. The W1 quasi 16-day waves exhibit a double peak structure in altitude over winter hemispheric high latitudes. The eastward propagating quasi 16-day waves with wave number 1 (E1; E1 refers to eastward propagating wave with zonal wave number 1) exhibits similar features as that of W1 waves in the NH. In contrast, the E1 quasi 16-day waves in the SH show larger amplitudes as compared to the W1 waves and they do not exhibit double peak structure in altitude. Similar to the quasi 16-day waves, the quasi 10- and 5-day wave amplitudes with respect to their wavenumbers are delineated. Unlike quasi-16 and -10 day waves, quasi-5 day waves peak during vernal equinox both in the SH and NH. The peak activity of the W1 quasi-5 day wave is centered around 40°N and 40°S exhibiting symmetry with respect to the equator. A detailed discussion on the height-latitude structure, interannual variability and inter-hemispheric propagation of quasi 16-, 10- and 5-day waves are discussed. The significance of the present study lies in establishing the 5-year climatology of normal mode planetary waves from the stratosphere to the MLT region including their spatial-temporal evolution, which are

  7. Transient state kinetics tutorial using the kinetics simulation program, KINSIM.

    PubMed Central

    Wachsstock, D H; Pollard, T D

    1994-01-01

    This article provides an introduction to a computer tutorial on transient state kinetics. The tutorial uses our Macintosh version of the computer program, KINSIM, that calculates the time course of reactions. KINSIM is also available for other popular computers. This program allows even those investigators not mathematically inclined to evaluate the rate constants for the transitions between the intermediates in any reaction mechanism. These rate constants are one of the insights that are essential for understanding how biochemical processes work at the molecular level. The approach is applicable not only to enzyme reactions but also to any other type of process of interest to biophysicists, cell biologists, and molecular biologists in which concentrations change with time. In principle, the same methods could be used to characterize time-dependent, large-scale processes in ecology and evolution. Completion of the tutorial takes students 6-10 h. This investment is rewarded by a deep understanding of the principles of chemical kinetics and familiarity with the tools of kinetics simulation as an approach to solve everyday problems in the laboratory. PMID:7811941

  8. SABER: A Theater Level Wargame

    DTIC Science & Technology

    1991-03-01

    Agile. Given a recently developed land battle, this thesis’ effort links US Air Force doctrine with a conceptual model’s frarework and designs a new air...gratefully appreciated. Without her, I would have lost touch with what is the big picture. I want to thank my children , Katharine and Harrison, who...to replace the Theater War Exercise (TWX), also known as Agile. Given a recently developed land battle, this thesis’ effort links US Air Force

  9. Erbium hydride thermal desorption : controlling kinetics.

    SciTech Connect

    Ferrizz, Robert Matthew

    2007-08-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report show that hydride film processing parameters directly impact thermal stability. Issues to be addressed include desorption kinetics for dihydrides and trihydrides, and the effect of film growth parameters, loading parameters, and substrate selection on desorption kinetics.

  10. Understanding Product Optimization: Kinetic versus Thermodynamic Control.

    ERIC Educational Resources Information Center

    Lin, King-Chuen

    1988-01-01

    Discusses the concept of kinetic versus thermodynamic control of reactions. Explains on the undergraduate level (1) the role of kinetic and thermodynamic control in kinetic equations, (2) the influence of concentration and temperature upon the reaction, and (3) the application of factors one and two to synthetic chemistry. (MVL)

  11. Understanding Product Optimization: Kinetic versus Thermodynamic Control.

    ERIC Educational Resources Information Center

    Lin, King-Chuen

    1988-01-01

    Discusses the concept of kinetic versus thermodynamic control of reactions. Explains on the undergraduate level (1) the role of kinetic and thermodynamic control in kinetic equations, (2) the influence of concentration and temperature upon the reaction, and (3) the application of factors one and two to synthetic chemistry. (MVL)

  12. Kinetic models of conjugated metabolic cycles

    NASA Astrophysics Data System (ADS)

    Ershov, Yu. A.

    2016-01-01

    A general method is developed for the quantitative kinetic analysis of conjugated metabolic cycles in the human organism. This method is used as a basis for constructing a kinetic graph and model of the conjugated citric acid and ureapoiesis cycles. The results from a kinetic analysis of the model for these cycles are given.

  13. The correct kinetic Bohm criterion

    NASA Astrophysics Data System (ADS)

    Czarnetzki, Uwe; Tsankov, Tsanko Vaskov

    2016-09-01

    Space charge sheaths are characteristic for bounded plasmas and are a key element in plasma-surface interactions. Hence, one of the most fundamental concepts in plasma physics - the Bohm criterion - is related to the definition of a sheath edge. However, its kinetic formulation is stirring controversies for a long time - from questioning its validity at high collisionality to claiming a divergence in its formulation. Here, based on a solution of the Boltzmann equation for ions with charge-exchange collisions and ionization both of these disputes are resolved: 1) The obtained form of the kinetic Bohm criterion removes the divergence in the ionic part. 2) It also introduces a new equally important term that describes collisional and geometric effects. This new term reestablishes the validity of the criterion at high collisionality. 3) It also restores agreement with the fluid counterpart of the criterion. The developed theory is supported by non-invasive spatially resolved measurements and a numerical model.

  14. Kinetic activation-relaxation technique.

    PubMed

    Béland, Laurent Karim; Brommer, Peter; El-Mellouhi, Fedwa; Joly, Jean-François; Mousseau, Normand

    2011-10-01

    We present a detailed description of the kinetic activation-relaxation technique (k-ART), an off-lattice, self-learning kinetic Monte Carlo (KMC) algorithm with on-the-fly event search. Combining a topological classification for local environments and event generation with ART nouveau, an efficient unbiased sampling method for finding transition states, k-ART can be applied to complex materials with atoms in off-lattice positions or with elastic deformations that cannot be handled with standard KMC approaches. In addition to presenting the various elements of the algorithm, we demonstrate the general character of k-ART by applying the algorithm to three challenging systems: self-defect annihilation in c-Si (crystalline silicon), self-interstitial diffusion in Fe, and structural relaxation in a-Si (amorphous silicon).

  15. Biochemical kinetics in changing volumes.

    PubMed

    Pawłowski, Piotr H; Zielenkiewicz, Piotr

    2004-01-01

    The need of taking into account the change of compartment volume when developing chemical kinetics analysis inside the living cell is discussed. Literature models of a single enzymatic Michaelis-Menten process, glycolytic oscillations, and mitotic cyclin oscillations were tested with appropriate theoretical extension in the direction of volume modification allowance. Linear and exponential type of volume increase regimes were compared. Due to the above, in a growing cell damping of the amplitude, phase shift, and time pattern deformation of the metabolic rhythms considered were detected, depending on the volume change character. The performed computer simulations allow us to conclude that evolution of the cell volume can be an essential factor of the chemical kinetics in a growing cell. The phenomenon of additional metabolite oscillations caused by the periodic cell growth and division was theoretically predicted and mathematically described. Also, the hypothesis of the periodized state in the growing cell as the generalization of the steady-state was formulated.

  16. Kinetic activation-relaxation technique

    NASA Astrophysics Data System (ADS)

    Béland, Laurent Karim; Brommer, Peter; El-Mellouhi, Fedwa; Joly, Jean-François; Mousseau, Normand

    2011-10-01

    We present a detailed description of the kinetic activation-relaxation technique (k-ART), an off-lattice, self-learning kinetic Monte Carlo (KMC) algorithm with on-the-fly event search. Combining a topological classification for local environments and event generation with ART nouveau, an efficient unbiased sampling method for finding transition states, k-ART can be applied to complex materials with atoms in off-lattice positions or with elastic deformations that cannot be handled with standard KMC approaches. In addition to presenting the various elements of the algorithm, we demonstrate the general character of k-ART by applying the algorithm to three challenging systems: self-defect annihilation in c-Si (crystalline silicon), self-interstitial diffusion in Fe, and structural relaxation in a-Si (amorphous silicon).

  17. Kinetic theory of relativistic plasmas

    NASA Technical Reports Server (NTRS)

    Gould, R. J.

    1981-01-01

    The thermalization of particle kinetic motion by binary collisions is considered for a plasma with a Boltzmann constant-temperature product approximately equal to 10 to 100 times the product of the electron mass with the square of the speed of light. At this temperature, the principal mechanism for relaxation of electron motion is via radiationless electron-electron collisions (Moller scattering). Ions are nonrelativistic, but are energetic enough so that their Coulomb scattering can be treated in the Born approximation. Relaxation times are computed and Boltzmann-equation Fokker-Planck operators are derived for the various binary-collision processes. The expression for the rate of kinetic energy exchange between electron and ion gases is derived for the case where the gases are at different temperatures.

  18. Kinetics of Polymer Interfacial Reaction

    NASA Astrophysics Data System (ADS)

    Zhang, Shuo; Koberstein, Jeffrey

    2012-02-01

    Germanium crystals modified with high quality azide functional monolayers are used to directly monitor in situ the kinetics of interfacial ``click'' reactions with complementary alkyne end-functional poly(n-butyl acrylate) (PnBA) and polystyrene (PS) by attenuated total reflectance infrared spectroscopy (ATR-IR). In the presence of copper (I), the azide-modified Ge substrates react quantitatively with PnBA and PS via a 1,3-dipolar cycloaddition reaction. Time-resolved ATR-IR measurements show two regimes of kinetic behavior, as predicted by theory. In the first regime the rate is rapid and is controlled by diffusion of the polymer through the solvent, scaling with the square root of time. The rate slows considerably in the second regime, limited by penetration of the reacting polymer through the covalently bound polymer brush layer, scaling with the natural logarithm of time. The influence of polymer size and solvent quality are reported.

  19. Kinetics of degenerate atomic gases

    NASA Astrophysics Data System (ADS)

    Geist, W.; You, L.; Kennedy, T. A. B.

    1998-05-01

    Using the Uehling-Uhlenbeck, or quantum Boltzmann equation, we discuss the kinetics and evaporative cooling of quantum degenerate gases confined in magnetic traps with cylindrical symmetry. We study the full nonergodic time evolution and compare with results obtained by making the ergodic or continuum energy approximation(C. W. Gardiner, P. Zoller, R. J. Ballagh, M. J. Davis, ``Quantum kinetic theory. Simulation of the quantum Boltzmann master equation'', Phys. Rev. A 56), 575 (1997).. We report evidence of strongly non-ergodic distribution functions, whose relaxation times do not coincide with other characteristic timescales, but depend on trap anisotropy. We also report our study of condensate growth which exhibits the same qualitative behaviour as observed in a recent experiment(H. J. Miesner, D. M. Stamper, M. R. Andrews, D. S. Durfee, S. Inouve, W. Ketterle, ``Bosonic stimulation in the formation of a Bose-Einstein condensate'', (preprint).). Preliminary results for sympathetic cooling of fermions by bosons will also be presented.

  20. Variational Approach to Molecular Kinetics.

    PubMed

    Nüske, Feliks; Keller, Bettina G; Pérez-Hernández, Guillermo; Mey, Antonia S J S; Noé, Frank

    2014-04-08

    The eigenvalues and eigenvectors of the molecular dynamics propagator (or transfer operator) contain the essential information about the molecular thermodynamics and kinetics. This includes the stationary distribution, the metastable states, and state-to-state transition rates. Here, we present a variational approach for computing these dominant eigenvalues and eigenvectors. This approach is analogous to the variational approach used for computing stationary states in quantum mechanics. A corresponding method of linear variation is formulated. It is shown that the matrices needed for the linear variation method are correlation matrices that can be estimated from simple MD simulations for a given basis set. The method proposed here is thus to first define a basis set able to capture the relevant conformational transitions, then compute the respective correlation matrices, and then to compute their dominant eigenvalues and eigenvectors, thus obtaining the key ingredients of the slow kinetics.

  1. Kinetic theory of Jeans instability.

    PubMed

    Trigger, S A; Ershkovich, A I; van Heijst, G J F; Schram, P P J M

    2004-06-01

    Kinetic treatment of the Jeans gravitational instability, with collisions taken into account, is presented. The initial-value problem for the distribution function which obeys the kinetic equation, with the collision integral conserving the number of particles, is solved. Dispersion relation is obtained and analyzed. New modes are found. Collisions are shown not to affect the Jeans instability criterion. Although the instability growth rate diminishes, the collisions they cannot quench the instability. However, the oscillation spectrum is modified significantly: even in the neighborhood of the threshold frequency omega=0 (separating stable and unstable modes) the spectrum of oscillations can strongly depend on the collision frequency. Propagating (rather than aperiodic) modes are also found. These modes, however, are strongly damped.

  2. Isoprene: a photochemical kinetic mechanism

    SciTech Connect

    Killus, J.P.; Whitten, G.Z.

    1984-03-01

    A computer-modeling study has produced a photochemical kinetic mechanism for the atmospheric chemistry of isoprene, a naturally occurring common constituent of the troposphere. The kinetic mechnism is ready for use in atmospheric models because the reactions described are shown to adequately reproduce the results of a series of outdoor smog chamber experiments which encompass a wide range of precursor conditions of isoprene and NO/sub x/. Isoprene is a very reactive molecule that can contribute as much as 50% of the overall reactivity of rural air even though isoprene might be only 6% of the ambient hydrocarbon level. The major intermediate products of the atmospheric oxidation of isoprene, methyl vinyl ketone, methacrolein, methylglyoxal, and formaldehyde are also highly reactive. 25 references.

  3. Kinetic approach to relativistic dissipation

    NASA Astrophysics Data System (ADS)

    Gabbana, A.; Mendoza, M.; Succi, S.; Tripiccione, R.

    2017-08-01

    Despite a long record of intense effort, the basic mechanisms by which dissipation emerges from the microscopic dynamics of a relativistic fluid still elude complete understanding. In particular, several details must still be finalized in the pathway from kinetic theory to hydrodynamics mainly in the derivation of the values of the transport coefficients. In this paper, we approach the problem by matching data from lattice-kinetic simulations with analytical predictions. Our numerical results provide neat evidence in favor of the Chapman-Enskog [The Mathematical Theory of Non-Uniform Gases, 3rd ed. (Cambridge University Press, Cambridge, U.K., 1970)] procedure as suggested by recent theoretical analyses along with qualitative hints at the basic reasons why the Chapman-Enskog expansion might be better suited than Grad's method [Commun. Pure Appl. Math. 2, 331 (1949), 10.1002/cpa.3160020403] to capture the emergence of dissipative effects in relativistic fluids.

  4. Kinetic mixing at strong coupling

    NASA Astrophysics Data System (ADS)

    Del Zotto, Michele; Heckman, Jonathan J.; Kumar, Piyush; Malekian, Arada; Wecht, Brian

    2017-01-01

    A common feature of many string-motivated particle physics models is additional strongly coupled U (1 )'s. In such sectors, electric and magnetic states have comparable mass, and integrating out modes also charged under U (1 ) hypercharge generically yields C P preserving electric kinetic mixing and C P violating magnetic kinetic mixing terms. Even though these extra sectors are strongly coupled, we show that in the limit where the extra sector has approximate N =2 supersymmetry, we can use formal methods from Seiberg-Witten theory to compute these couplings. We also calculate various quantities of phenomenological interest such as the cross section for scattering between visible sector states and heavy extra sector states as well as the effects of supersymmetry breaking induced from coupling to the minimal supersymmetric Standard Model.

  5. Kinetic stability of membrane proteins.

    PubMed

    González Flecha, F Luis

    2017-09-18

    Although membrane proteins constitute an important class of biomolecules involved in key cellular processes, study of the thermodynamic and kinetic stability of their structures is far behind that of soluble proteins. It is known that many membrane proteins become unstable when removed by detergent extraction from the lipid environment. In addition, most of them undergo irreversible denaturation, even under mild experimental conditions. This process was found to be associated with partial unfolding of the polypeptide chain exposing hydrophobic regions to water, and it was proposed that the formation of kinetically trapped conformations could be involved. In this review, we will describe some of the efforts toward understanding the irreversible inactivation of membrane proteins. Furthermore, its modulation by phospholipids, ligands, and temperature will be herein discussed.

  6. Nonlinear theory of drift-cyclotron kinetics and the possible breakdown of gyro-kinetics

    SciTech Connect

    Waltz, R. E.; Deng Zhao

    2013-01-15

    A nonlinear theory of drift-cyclotron kinetics (termed cyclo-kinetics here) is formulated to test the breakdown of the gyro-kinetic approximations. Six dimensional cyclo-kinetics can be regarded as an extension of five dimensional gyro-kinetics to include high-frequency cyclotron waves, which can interrupt the low-frequency gyro-averaging in the (sixth velocity grid) gyro-phase angle. Nonlinear cyclo-kinetics has no limit on the amplitude of the perturbations. Formally, there is no gyro-averaging when all cyclotron (gyro-phase angle) harmonics of the perturbed distribution function (delta-f) are retained. Retaining only the (low frequency) zeroth cyclotron harmonic in cyclo-kinetics recovers both linear and nonlinear gyro-kinetics. Simple recipes are given for converting continuum nonlinear delta-f gyro-kinetic transport simulation codes to cyclo-kinetics codes by retaining (at least some) higher cyclotron harmonics.

  7. Kinetic studies of ICF implosions

    DOE PAGES

    Kagan, Grigory; Herrmann, H. W.; Kim, Y. -H.; ...

    2016-05-26

    Here, kinetic effects on inertial confinement fusion have been investigated. In particular, inter-ion-species diffusion and suprathermal ion distribution have been analyzed. The former drives separation of the fuel constituents in the hot reacting core and governs mix at the shell/fuel interface. The latter underlie measurements obtained with nuclear diagnostics, including the fusion yield and inferred ion burn temperatures. Basic mechanisms behind and practical consequences from these effects are discussed.

  8. Multiflow approach to plasma kinetics

    SciTech Connect

    Ignatov, A. M.

    2015-10-15

    Instead of the commonly used Vlasov equation, one is able to treat kinetic phenomena in collisionless plasma with the help of the infinite set of hydrodynamic equations. The present paper deals with the linear approximation of multiflow hydrodynamics. It is shown that single-particle and collective excitations analogous to Van Kampen waves are explicitly separated. Expressions for the energy of all eigenmodes are obtained.

  9. Ion Kinetics in Silane Plasmas

    DTIC Science & Technology

    1988-02-01

    reaction are determined not only by the chemical reactivity but by the electrical properties of the plasma. Current continuity, impedence match- ing...conventional kinetic theory. Since the chemical and physical properties of the noble-gases vary monotonically down the periods of Mendeleev’s table, one...formation. Most literature with the phrase ion chemistry in its title is concerned only with the properties and reactions of positively charged species

  10. Bumetanide kinetics in renal failure

    SciTech Connect

    Pentikaeinen, P.J.P.; Pasternack, A.; Lampainen, E.; Neuvonen, P.J.; Penttilae, A.

    1985-05-01

    To study the effects of renal failure on bumetanide kinetics, the authors administered single intravenous doses of 1.0 mg/3.08 microCi /sup 14/C-bumetanide to six healthy subjects and 22 patients with variable degrees of renal failure. The kinetics of /sup 14/C-bumetanide and total /sup 14/C were adequately described by a two-compartment open model in the control subjects and in the patients. The volume of the central compartment and the distribution t1/2 were of the same order in both groups, whereas the mean (+/- SE) volume at steady state was larger (22.1 +/- 1.6 and 16.9 +/- 1.0 L) and the elimination t1/2 was longer (1.9 +/- 0.2 and 1.4 +/- 0.1 hours) in patients with renal failure than in healthy controls. Bumetanide renal clearance was lower (10 +/- 3 and 90 +/- 13 ml/min) in patients than in subjects and correlated with creatinine clearance (r = 0.784) and log serum creatinine level (r = -0.843), whereas nonrenal clearance was significantly higher in the patients (153 +/- /sup 14/ and 99 +/- 6 ml/min). Bumetanide total plasma clearance did not significantly change. The non-protein-bound, free fraction of bumetanide was higher in patients and correlated with plasma albumin levels (r = -0.777). The kinetics of total /sup 14/C showed similar but greater changes than those of 14C-bumetanide. Thus the most important changes in bumetanide kinetics in patients with renal failure are low renal clearance and a high free fraction, with a consequent increase in nonrenal clearance, volume of distribution, and elimination t1/2.

  11. Kinetic Theory and Fluid Dynamics

    NASA Astrophysics Data System (ADS)

    Sone, Yoshio

    This monograph gives a comprehensive description of the relationship and connections between kinetic theory and fluid dynamics, mainly for a time-independent problem in a general domain. Ambiguities in this relationship are clarified, and the incompleteness of classical fluid dynamics in describing the behavior of a gas in the continuum limit—recently reported as the ghost effect—is also discussed. The approach used in this work engages an audience of theoretical physicists, applied mathematicians, and engineers. By a systematic asymptotic analysis, fluid-dynamic-type equations and their associated boundary conditions that take into account the weak effect of gas rarefaction are derived from the Boltzmann system. Comprehensive information on the Knudsen-layer correction is also obtained. Equations and their boundary conditions are carefully classified depending on the physical context of problems. Applications are presented to various physically interesting phenomena, including flows induced by temperature fields, evaporation and condensation problems, examples of the ghost effect, and bifurcation of flows. Key features: * many applications and physical models of practical interest * experimental works such as the Knudsen compressor are examined to supplement theory * engineers will not be overwhelmed by sophisticated mathematical techniques * mathematicians will benefit from clarity of definitions and precise physical descriptions given in mathematical terms * appendices collect key derivations and formulas, important to the practitioner, but not easily found in the literature Kinetic Theory and Fluid Dynamics serves as a bridge for those working in different communities where kinetic theory or fluid dynamics is important: graduate students, researchers and practitioners in theoretical physics, applied mathematics, and various branches of engineering. The work can be used in graduate-level courses in fluid dynamics, gas dynamics, and kinetic theory; some parts

  12. Kinetic model of HIV infection

    SciTech Connect

    Zhdanov, V. P.

    2007-10-15

    Recent experiments clarifying the details of exhaustion of CD8 T cells specific to various strains of human immunodeficiency virus (HIV) are indicative of slow irreversible (on a one-year time scale) deterioration of the immune system. The conventional models of HIV kinetics do not take this effect into account. Removing this shortcoming, we show the likely influence of such changes on the escape of HIV from control of the immune system.

  13. Kinetics of accelerator driven devices

    SciTech Connect

    Perry, R.T.; Buksa, J.; Houts, M.

    1994-09-01

    Kinetic calculations were made to show that subcritical accelerator driven devices are robust and stable. The calculations show that large changes in reactivity that would lead to an uncontrollable excursion in a reactor would lead only to a new power level in subcritical device. Calculations were also made to show the rate of power changes resulting from startup and shutdown, and that methods also exist for continuously monitoring the reactivity of a subcritical system.

  14. The KInetic Database for Astrochemistry

    NASA Astrophysics Data System (ADS)

    Wakelam, V.

    2010-12-01

    KIDA (for KInetic Database for Astrochemistry) is a project initiated by different communities in order to 1) improve the interaction between astrochemists and physico-chemists and 2) simplify the work of modeling the chemistry of astrophysical environments. Here astrophysical environments stand for the interstellar medium and planetary atmospheres. Both types of environments use similar chemical networks and the physico-chemists who work on the determination of reaction rate coefficients for both types of environment are the same.

  15. Multienzyme kinetics and sequential metabolism.

    PubMed

    Wienkers, Larry C; Rock, Brooke

    2014-01-01

    Enzymes are the catalysts of biological systems and are extremely efficient. A typical enzyme accelerates the rate of a reaction by factors of at least a million compared to the rate of the same reaction in the absence of the enzyme. In contrast to traditional catalytic enzymes, the family of cytochrome P450 (CYP) enzymes are catalytically promiscuous, and thus they possess remarkable versatility in substrates. The great diversity of reactions catalyzed by CYP enzymes appears to be based on two unique properties of these heme proteins, the ability of their iron to exist under multiple oxidation states with different reactivities and a flexible active site that can accommodate a wide variety of substrates. Herein is a discussion of two distinct types of kinetics observed with CYP enzymes. The first example is of CYP complex kinetic profiles when multiple CYP enzymes form the sample product. The second is sequential metabolism, in other words, the formation of multiple products from one CYP enzyme. Given the degree of CYP enzyme promiscuity, it is hardly surprising that there is also a high degree of complex kinetic profiles generated during the catalytic cycle.

  16. The kinetics of hydrocarbon cracking

    SciTech Connect

    Groten, W.A.; Wojciechowski, B.W. )

    1993-03-01

    A general kinetic model which describes the catalytic cracking of pure hydrocarbons is presented. The model includes a monomolecular cracking path based on the Langmuir adsorption isotherm as well as a bimolecular path, following Rideal kinetics, which accounts for the possibility of a chain cracking mechanism being involved. Catalyst decay is accounted for using the time-on-stream-decay function. Fitting of experimental data from n-nonane cracking on USHY at 673 K, combined with Monte Carlo simulations indicates that, in that case, the total catalytic activity could include between 0 and 90% of activity due to chain processes. This large margin of error stems from the combined effects of a large decay rate, forcing the experimenter to use average conversion data, and of experimental error. Fitting of the model to previously published cracking data for 2-methylpentane on USHY showed that the model lacks a suitable parameter to account for thermal reactions which were not accounted for in the original data set. This observation supports the impression that the model is sensitive to departures from the postulated mechanism. The above kinetic model has also been fitted to the results of n-nonane cracking at three temperatures as well as to previously published data for various other linear paraffins. 32 refs., 17 figs., 6 tabs.

  17. Kinetically accessible compact conformations of chain molecules

    NASA Astrophysics Data System (ADS)

    Yoshie, Naoko; Yamamoto, Keigo

    1998-05-01

    The kinetic accessibility of various compact conformations of chain molecules is studied using a short self-avoiding chain on a three-dimensional cubic lattice. The kinetic accessibility of a compact conformation depends on the conformational energy and the distances from the other conformations along kinetically possible trajectories. We focus on the kinetic distances. We consider a chain in a poor solvent, having multiple lowest-energy compact conformations. The chain collapse from an arbitrary conformation to one of the lowest energy conformations is investigated. Though the lowest energy states would be occupied with the same probability in equilibrium, the probabilities for a first hit are not necessarily all the same and they indeed are not. We show that the hit probability at low temperature can be used as a measure of the kinetic distances from other conformations. The hit probability is investigated under two kinetic processes. One is a Monte Carlo dynamic process and the other is a "contact-set stepping" process, in which kinetic distances between conformations are defined based on sets of contacts. The two kinetic processes exhibit similar results showing that both processes well reproduce the kinetic behavior of chain molecules. Through the characterization of the states with large hit probability at low temperature, we show that the influence of the kinetic distances on the kinetic accessibility can be explained by domain structure or locality of contacts.

  18. What do we learn about the impact of extreme hydrological events on tropical wetlands from the synergistic use of altimetry from Sentinel-3/SARAL-Altika and L-Band radiometry from SMOS/SMAP ?

    NASA Astrophysics Data System (ADS)

    Al Bitar, Ahmad; Parrens, Marie; Frappart, Frederic; Cauduro Dias de Paiva, Rodrigo; Papa, Fabrice; Kerr, Yann

    2017-04-01

    What do we learn about the impact of extreme hydrological events on tropical wetlands from the synergistic use of altimetry from Sentinel-3/SARAL-Altika and L-Band radiometry from SMOS/SMAP ? The question of the contribution of the tropical basins to the carbon and water cycle remains an open question in the science community. The tropical basins are highly impact by the wetlands dynamics but the also the link with extreme events like El-Nino are yet to be clarified. The main reason to this uncertainty is that the monitoring of inland water surfaces via remote sensing over tropical areas is a difficult task because of impact of vegetation and cloud cover. The most common solution is to use microwave remote sensing. In this study we combine the use of L-band microwave brightness temperatures and altimetric data from SARAL/ALTIKA and Sentinel-3 to derive water storage maps at relatively high (7days) temporal frequency. This study concerns the Amazon and Congo basin. The water fraction in inland are estimated by inversing a first order radiative model is used to derive surface water over land from the brightness temperature measured by ESA SMOS and SMAP mission at coarse resolution (25 km x 25 km) and 7-days frequency. The product is compared to the static land cover map such as ESA CCI and the International Geosphere-Biosphere Program (IGBP) and also dynamic maps from GIEMS and SWAPS products. Water storage is then obtained by combining the altimetric data from SARAL/ALTIKA and Sentinel-3 to the water surface fraction using an hypsometric approach. The water surfaces and water storage products are then compared to precipitation data from GPM TRMM datasets and river discharge data from field data. The amplitudes and time shifts of the signals is compared based on the sub-basin definition from Hydroshed database. The dataset is then divided into years of strong and weak El-Nino signal and the anomaly is between the two dataset is compared. The results show a strong

  19. Reaction networks and kinetics of biochemical systems.

    PubMed

    Arceo, Carlene Perpetua P; Jose, Editha C; Lao, Angelyn R; Mendoza, Eduardo R

    2017-01-01

    This paper further develops the connection between Chemical Reaction Network Theory (CRNT) and Biochemical Systems Theory (BST) that we recently introduced [1]. We first use algebraic properties of kinetic sets to study the set of complex factorizable kinetics CFK(N) on a CRN, which shares many characteristics with its subset of mass action kinetics. In particular, we extend the Theorem of Feinberg-Horn [9] on the coincidence of the kinetic and stoichiometric subsets of a mass action system to CF kinetics, using the concept of span surjectivity. We also introduce the branching type of a network, which determines the availability of kinetics on it and allows us to characterize the networks for which all kinetics are complex factorizable: A "Kinetics Landscape" provides an overview of kinetics sets, their algebraic properties and containment relationships. We then apply our results and those (of other CRNT researchers) reviewed in [1] to fifteen BST models of complex biological systems and discover novel network and kinetic properties that so far have not been widely studied in CRNT. In our view, these findings show an important benefit of connecting CRNT and BST modeling efforts. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Oxidation kinetics of aluminum diboride

    SciTech Connect

    Whittaker, Michael L.; Sohn, H.Y.; Cutler, Raymond A.

    2013-11-15

    The oxidation characteristics of aluminum diboride (AlB{sub 2}) and a physical mixture of its constituent elements (Al+2B) were studied in dry air and pure oxygen using thermal gravimetric analysis to obtain non-mechanistic kinetic parameters. Heating in air at a constant linear heating rate of 10 °C/min showed a marked difference between Al+2B and AlB{sub 2} in the onset of oxidation and final conversion fraction, with AlB{sub 2} beginning to oxidize at higher temperatures but reaching nearly complete conversion by 1500 °C. Kinetic parameters were obtained in both air and oxygen using a model-free isothermal method at temperatures between 500 and 1000 °C. Activation energies were found to decrease, in general, with increasing conversion for AlB{sub 2} and Al+2B in both air and oxygen. AlB{sub 2} exhibited O{sub 2}-pressure-independent oxidation behavior at low conversions, while the activation energies of Al+2B were higher in O{sub 2} than in air. Differences in the composition and morphology between oxidized Al+2B and AlB{sub 2} suggested that Al{sub 2}O{sub 3}–B{sub 2}O{sub 3} interactions slowed Al+2B oxidation by converting Al{sub 2}O{sub 3} on aluminum particles into a Al{sub 4}B{sub 2}O{sub 9} shell, while the same Al{sub 4}B{sub 2}O{sub 9} developed a needle-like morphology in AlB{sub 2} that reduced oxygen diffusion distances and increased conversion. The model-free kinetic analysis was critical for interpreting the complex, multistep oxidation behavior for which a single mechanism could not be assigned. At low temperatures, moisture increased the oxidation rate of Al+2B and AlB{sub 2}, but both appear to be resistant to oxidation in cool, dry environments. - Graphical abstract: Isothermal kinetic data for AlB{sub 2} in air, showing a constantly decreasing activation energy with increasing conversion. Model-free analysis allowed for the calculation of global kinetic parameters despite many simultaneous mechanisms occurring concurrently. (a) Time

  1. Kinetics of photoacclimation in corals.

    PubMed

    Anthony, Kenneth R N; Hoegh-Guldberg, Ove

    2003-01-01

    Traditional models describing the relationship between photosynthesis (P) and irradiance (I) do not account for photoacclimation to short-term variation in irradiance. Here we develop and test a model that predicts the rate of photosynthesis under fluctuating irradiances at the scale of days to weeks. Using oxygen respirometry, we measured the rates of change in the P-I model parameters P(max) (maximum rate of gross photosynthesis) and I(k) (sub-saturation irradiance) of the photo-symbiotic coral Turbinaria mesenterina (Lamarck) following large and small increases and decreases in growth irradiance. We analyse the behaviour of the dynamic P-I model in turbid-water conditions using a dataset of 3-month continuous irradiance as the input variable. In response to upward or downward changes in experimental growth irradiance, I(k) values decreased or increased exponentially, reaching new and stable levels within 5-10 days. I(k) responded 4 times stronger than P(max) to changes in growth irradiance. The kinetics of I(k) did not show hysteresis, and changed in similar ways when irradiance was increased or decreased in small or large amounts. This suggests that mechanisms associated with photo-protection during increases in irradiance, and the maximisation of photosynthetic efficiency during decreases in irradiance, are equally potent. On the scale of months, the dynamic P-I model did not predict higher rates of photosynthesis than the static P-I model, but buffered the variation in photosynthesis during periods of reduced irradiance. Fourier analysis indicated that the kinetics of I(k) closely matches the main periodicities in daily irradiance (1-2 weeks). The recorded kinetics of photoacclimation in the Turbinaria-zooxanthella symbiosis is comparable to that of free-living phytoplankton and faster than that of higher plants.

  2. Kinetic potentials in quantum mechanics

    NASA Astrophysics Data System (ADS)

    Hall, Richard L.

    1984-09-01

    Suppose that the Hamiltonian H=-Δ+vf(r) represents the energy of a particle which moves in an attractive central potential and obeys nonrelativistic quantum mechanics. The discrete eigenvalues Enl=Fnl(v) of H may be expressed as a Legendre transformation Fnl(v)=mins≳0(s+vf¯nl(s)), n=1,2,3,..., l=0,1,2,..., where the ``kinetic potentials'' f¯nl(s) associated with f(r) are defined by f¯nl(s) =infDnl supψ∈Dnl, ∥ψ∥=1 ∫ ψ(r) f ([ψ,-Δψ)/s]1/2r)ψ(r)d3r, and Dnl is an n-dimensional subspace of L2(R3) labeled by Ylm(θ,φ), m=0, and contained in the domain D(H) of H. If the potential has the form f(r)=∑Ni=1 g(i)( f(i)(r)) then in many interesting cases it turns out that the corresponding kinetic potentials can be closely approximated by ∑Ni=1 g(i)( f¯nl(i)(s)). This nice behavior of the kinetic potentials leads to a constructive global approximation theory for Schrödinger eigenvalues. As an illustration, detailed recipes are provided for arbitrary linear combinations of power-law potentials and the log potential. For the linear plus Coulomb potential and the quartic anharmonic oscillator the approximate eigenvalues are compared to accurate values found by numerical integration.

  3. Freezing Kinetics in Overcompressed Water

    SciTech Connect

    Bastea, M; Bastea, S; Reaugh, J; Reisman, D

    2006-09-27

    We report high pressure dynamic compression experiments of liquid water along a quasi-adiabatic path leading to the formation of ice VII. We observe dynamic features resembling Van der Waals loops and find that liquid water is compacted to a metastable state close to the ice density before the onset of crystallization. By analyzing the characteristic kinetic time scale involved we estimate the nucleation barrier and conclude that liquid water has been compressed to a high pressure state close to its thermodynamic stability limit.

  4. Rare Gas Halide (RGH) Kinetics.

    DTIC Science & Technology

    1988-02-01

    Technolog , Inc.. 2755 Northup Way, Bellevue, Washington 98004-1495 (Received Il August 1987; accepted for publication 12 October 1987) Time-dependent density...8217 - Z ¢L --- ;-; Z¢ < : 2 2 2 e - 2 l ¢ - -- - P-2 -V, 2 " ’ ’’’ 2.,..’ * -x ’ ,’* - SSpectra Technology flT U Fr CoPY CContract N00014-85-C-084 3...RARE GAS HALIDE (RGH) in KINETICS FINAL REPORT< S Submitted to OFFICE OF NAVAL RESEARCH DEPARTMENT OF THE NAVY Submitted by SPECTRA TECHNOLOGY , INC

  5. Kinetic theory of cluster dynamics

    NASA Astrophysics Data System (ADS)

    Patterson, Robert I. A.; Simonella, Sergio; Wagner, Wolfgang

    2016-11-01

    In a Newtonian system with localized interactions the whole set of particles is naturally decomposed into dynamical clusters, defined as finite groups of particles having an influence on each other's trajectory during a given interval of time. For an ideal gas with short-range intermolecular force, we provide a description of the cluster size distribution in terms of the reduced Boltzmann density. In the simplified context of Maxwell molecules, we show that a macroscopic fraction of the gas forms a giant component in finite kinetic time. The critical index of this phase transition is in agreement with previous numerical results on the elastic billiard.

  6. Kinetic Modeling of Microbiological Processes

    SciTech Connect

    Liu, Chongxuan; Fang, Yilin

    2012-08-26

    Kinetic description of microbiological processes is vital for the design and control of microbe-based biotechnologies such as waste water treatment, petroleum oil recovery, and contaminant attenuation and remediation. Various models have been proposed to describe microbiological processes. This editorial article discusses the advantages and limiation of these modeling approaches in cluding tranditional, Monod-type models and derivatives, and recently developed constraint-based approaches. The article also offers the future direction of modeling researches that best suit for petroleum and environmental biotechnologies.

  7. Kinetics of Supercritical Water Oxidation

    DTIC Science & Technology

    2007-11-02

    Donald R. Hardesty April 1 - June 30,1995 Project description: This project consists of experiments and theoretical modeling designed to improv...Washington. D.C., 4/95. D.R. Hardesty , "Kinetic Mechanisms of Supercritical Water Oxidation" presented at the FY95 In Progress Review. 5/95 Ft...McLean, 8300 MS9051 L. Rahn, 8351 MS9055 F. Tully, 8353 MS9056 G. Fisk, 8355 MS9052 D.R. Hardesty , 8361 Attn: Allendorf, S Allendorf, M

  8. Damage kinetics in silicon carbide

    NASA Astrophysics Data System (ADS)

    Pickup, I. M.; Barker, A. K.

    1998-07-01

    Three silicon carbides of similar density and grain size but manufactured via different routes (reaction bonded, pressureless sintered and pressure assisted densification) have been investigated. High speed photography in conjunction with Hopkinson pressure bar compression tests has revealed that not only does the manufacturing route confer a significant difference in failure kinetics but also modifies the phenomenology of failure. Plate impact experiments using lateral and longitudinal manganin stress gauges have been used to study shear strength behaviour of damaged material. Failure waves have been observed in all three materials and characteristically different damaged material shear strength relationships with pressure have been observed.

  9. Damage kinetics in silicon carbide

    SciTech Connect

    Pickup, I. M.; Barker, A. K.

    1998-07-10

    Three silicon carbides of similar density and grain size but manufactured via different routes (reaction bonded, pressureless sintered and pressure assisted densification) have been investigated. High speed photography in conjunction with Hopkinson pressure bar compression tests has revealed that not only does the manufacturing route confer a significant difference in failure kinetics but also modifies the phenomenology of failure. Plate impact experiments using lateral and longitudinal manganin stress gauges have been used to study shear strength behaviour of damaged material. Failure waves have been observed in all three materials and characteristically different damaged material shear strength relationships with pressure have been observed.

  10. Kinetic Effects in Dynamic Wetting

    NASA Astrophysics Data System (ADS)

    Sprittles, James E.

    2017-03-01

    The maximum speed at which a liquid can wet a solid is limited by the need to displace gas lubrication films in front of the moving contact line. The characteristic height of these films is often comparable to the mean free path in the gas so that hydrodynamic models do not adequately describe the flow physics. This Letter develops a model which incorporates kinetic effects in the gas, via the Boltzmann equation, and can predict experimentally observed increases in the maximum speed of wetting when (a) the liquid's viscosity is varied, (b) the ambient gas pressure is reduced, or (c) the meniscus is confined.

  11. Kinetic chain rehabilitation: a theoretical framework.

    PubMed

    Sciascia, Aaron; Cromwell, Robin

    2012-01-01

    Sequenced physiologic muscle activations in the upper and lower extremity result in an integrated biomechanical task. This sequencing is known as the kinetic chain, and, in upper extremity dominant tasks, the energy development and output follows a proximal to distal sequencing. Impairment of one or more kinetic chain links can create dysfunctional biomechanical output leading to pain and/or injury. When deficits exist in the preceding links, they can negatively affect the shoulder. Rehabilitation of shoulder injuries should involve evaluation for and restoration of all kinetic chain deficits that may hinder kinetic chain function. Rehabilitation programs focused on eliminating kinetic chain deficits, and soreness should follow a proximal to distal rationale where lower extremity impairments are addressed in addition to the upper extremity impairments. A logical progression focusing on flexibility, strength, proprioception, and endurance with kinetic chain influence is recommended.

  12. Kinetically guided colloidal structure formation

    PubMed Central

    Hecht, Fabian M.; Bausch, Andreas R.

    2016-01-01

    The self-organization of colloidal particles is a promising approach to create novel structures and materials, with applications spanning from smart materials to optoelectronics to quantum computation. However, designing and producing mesoscale-sized structures remains a major challenge because at length scales of 10–100 μm equilibration times already become prohibitively long. Here, we extend the principle of rapid diffusion-limited cluster aggregation (DLCA) to a multicomponent system of spherical colloidal particles to enable the rational design and production of finite-sized anisotropic structures on the mesoscale. In stark contrast to equilibrium self-assembly techniques, kinetic traps are not avoided but exploited to control and guide mesoscopic structure formation. To this end the affinities, size, and stoichiometry of up to five different types of DNA-coated microspheres are adjusted to kinetically control a higher-order hierarchical aggregation process in time. We show that the aggregation process can be fully rationalized by considering an extended analytical DLCA model, allowing us to produce mesoscopic structures of up to 26 µm in diameter. This scale-free approach can easily be extended to any multicomponent system that allows for multiple orthogonal interactions, thus yielding a high potential of facilitating novel materials with tailored plasmonic excitation bands, scattering, biochemical, or mechanical behavior. PMID:27444018

  13. Kinetics of Propargyl Radical Dissociation.

    PubMed

    Klippenstein, Stephen J; Miller, James A; Jasper, Ahren W

    2015-07-16

    Due to the prominent role of the propargyl radical for hydrocarbon growth within combustion environments, it is important to understand the kinetics of its formation and loss. The ab initio transition state theory-based master equation method is used to obtain theoretical kinetic predictions for the temperature and pressure dependence of the thermal decomposition of propargyl, which may be its primary loss channel under some conditions. The potential energy surface for the decomposition of propargyl is first mapped at a high level of theory with a combination of coupled cluster and multireference perturbation calculations. Variational transition state theory is then used to predict the microcanonical rate coefficients, which are subsequently implemented within the multiple-well multiple-channel master equation. A variety of energy transfer parameters are considered, and the sensitivity of the thermal rate predictions to these parameters is explored. The predictions for the thermal decomposition rate coefficient are found to be in good agreement with the limited experimental data. Modified Arrhenius representations of the rate constants are reported for utility in combustion modeling.

  14. Oxidation kinetics of polycrystalline silicon

    SciTech Connect

    Demirlioglu, E.K.

    1989-01-01

    Polysilicon continues to find applications in integrated circuits, both as a substrate for devices and as an actual device component. Polysilicon oxides are particularly important in the fabrication of memory devices such as EPROMs and EEPROMs. In studies of polysilicon oxidation kinetics, it has been observed that undoped and p-type polysilicon both oxidize in a manner similar to <110>-oriented single-crystal silicon. The data in the literature on n-type polysilicon oxidation, however, are limited, have been obtained under different experimental conditions, and often report contradictory results. The oxidation kinetics of doped polysilicon in dry O{sub 2} are examined at several phosphorus concentrations in the 800 to 1000{degree}C range. The oxidation rate of doped polysilicon is found to be slower than that of similarly doped <111>-oriented single-crystal silicon at dopant concentrations below the solid-solubility limit. The similarities and differences between doped polysilicon and single-crystal silicon oxidation are explained on the basis of a previously proposed parallel-oxidation model.

  15. Combustion kinetics and reaction pathways

    SciTech Connect

    Klemm, R.B.; Sutherland, J.W.

    1993-12-01

    This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

  16. Kinetic models of immediate exchange

    NASA Astrophysics Data System (ADS)

    Heinsalu, Els; Patriarca, Marco

    2014-08-01

    We propose a novel kinetic exchange model differing from previous ones in two main aspects. First, the basic dynamics is modified in order to represent economies where immediate wealth exchanges are carried out, instead of reshufflings or uni-directional movements of wealth. Such dynamics produces wealth distributions that describe more faithfully real data at small values of wealth. Secondly, a general probabilistic trading criterion is introduced, so that two economic units can decide independently whether to trade or not depending on their profit. It is found that the type of the equilibrium wealth distribution is the same for a large class of trading criteria formulated in a symmetrical way with respect to the two interacting units. This establishes unexpected links between and provides a microscopic foundations of various kinetic exchange models in which the existence of a saving propensity is postulated. We also study the generalized heterogeneous version of the model in which units use different trading criteria and show that suitable sets of diversified parameter values with a moderate level of heterogeneity can reproduce realistic wealth distributions with a Pareto power law.

  17. Kinetics of corneal thermal shrinkage

    NASA Astrophysics Data System (ADS)

    Borja, David; Manns, Fabrice; Lee, William E.; Parel, Jean-Marie

    2004-07-01

    Purpose: The purpose of this study was to determine the effects of temperature and heating duration on the kinetics of thermal shrinkage in corneal strips using a custom-made shrinkage device. Methods: Thermal shrinkage was induced and measured in corneal strips under a constant load placed while bathed in 25% Dextran irrigation solution. A study was performed on 57 Florida Lions Eye Bank donated human cadaver eyes to determine the effect of temperature on the amount and rate of thermal shrinkage. Further experiments were performed on 20 human cadaver eyes to determine the effects of heating duration on permanent shrinkage. Data analysis was performed to determine the effects of temperature, heating duration, and age on the amount and kinetics of shrinkage. Results: Shrinkage consisted of two phases: a shrinkage phase during heating and a regression phase after heating. Permanent shrinkage increased with temperature and duration. The shrinkage and regression time constants followed Arrhenius type temperature dependence. The shrinkage time constants where calculated to be 67, 84, 121, 560 and 1112 (s) at 80, 75, 70, 65, and 60°C respectively. At 65°C the permanent shrinkage time constant was calculated to be 945s. Conclusion: These results show that shrinkage treatments need to raise the temperature of the tissue above 75°C for several seconds in order to prevent regression of the shrinkage effect immediately after treatment and to induce the maximum amount of permanent irreversible shrinkage.

  18. Kinetics of actinide complexation reactions

    SciTech Connect

    Nash, K.L.; Sullivan, J.C.

    1997-09-01

    Though the literature records extensive compilations of the thermodynamics of actinide complexation reactions, the kinetics of complex formation and dissociation reactions of actinide ions in aqueous solutions have not been extensively investigated. In light of the central role played by such reactions in actinide process and environmental chemistry, this situation is somewhat surprising. The authors report herein a summary of what is known about actinide complexation kinetics. The systems include actinide ions in the four principal oxidation states (III, IV, V, and VI) and complex formation and dissociation rates with both simple and complex ligands. Most of the work reported was conducted in acidic media, but a few address reactions in neutral and alkaline solutions. Complex formation reactions tend in general to be rapid, accessible only to rapid-scan and equilibrium perturbation techniques. Complex dissociation reactions exhibit a wider range of rates and are generally more accessible using standard analytical methods. Literature results are described and correlated with the known properties of the individual ions.

  19. Lumped Element Kinetic Inductance Detectors

    NASA Astrophysics Data System (ADS)

    Doyle, S.; Mauskopf, P.; Naylon, J.; Porch, A.; Duncombe, C.

    2008-04-01

    Kinetic Inductance Detectors (KIDs) provide a promising solution to the problem of producing large format arrays of ultra sensitive detectors for astronomy. Traditionally KIDs have been constructed from superconducting quarter-wave resonant elements capacitively coupled to a co-planar feed line [1]. Photon detection is achieved by measuring the change in quasi-particle density caused by the splitting of Cooper pairs in the superconducting resonant element. This change in quasi-particle density alters the kinetic inductance, and hence the resonant frequency of the resonant element. This arrangement requires the quasi-particles generated by photon absorption to be concentrated at positions of high current density in the resonator. This is usually achieved through antenna coupling or quasi-particle trapping. For these detectors to work at wavelengths shorter than around 500 μm where antenna coupling can introduce a significant loss of efficiency, then a direct absorption method needs to be considered. One solution to this problem is the Lumped Element KID (LEKID), which shows no current variation along its length and can be arranged into a photon absorbing area coupled to free space and therefore requiring no antennas or quasi-particle trapping. This paper outlines the relevant microwave theory of a LEKID, along with theoretical and measured performance for these devices.

  20. Mechanisms and Kinetics of Catalytic Reactions

    DTIC Science & Technology

    1990-08-01

    CHEMICAL RESEARCH, r- DEVELOPMENT 5 N ENGINEERING CRDE-R-084 "" CENTER CENER(GC-TR-1728-008) ’ 04 N MECHANISMS AND KINETICS OF CATALYTIC REACTIONS Q...and Kinetics of Catalytic Reactions &AUTHOR(S) Garlick, Stephanie M. 7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) . PERFORMING ORGANIZATION...Tables........................87 vi MECHANISMS AND KINETICS OF CATALYTIC REACTIONS 1. INTRODUCTION The hydrolysis of phosphate esters in microemulsion