Science.gov

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) Observations of Polar Winter Conditions in 2009; Comparisons with Years 2002-2008

    DTIC Science & Technology

    2011-02-03

    Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, with a specific focus on the year 2009...using Broadband Emission Radiometry (SABER) instrument [1] on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite prior...are more com- mon. Current understanding of the causes of SSWs focuses upon the role of planetary waves (PWs) in forcing the most dramatic changes

  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.; Xu, Xiaojing

    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. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. "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)

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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…

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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).

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Breast tissue phantoms to assist compression study for cancer detection using microwave radiometry.

    PubMed

    Akki, Rachana S; Arunachalam, Kavitha

    2014-01-01

    Microwave radiometry is a passive imaging modality proposed for breast cancer detection without the need for ionizing radiation. Detection of breast tumor using radiometry is challenging as the intensity of thermal radiation received by the antenna is influenced by tumor stage, location, physiological conditions and the imaging setup. The controllable parameters for setting up a good imaging modality for early detection of breast cancer are ambient temperature (Ta), convection cooling of tissue surface (h), and tissue compression (c). Amongst these parameters tissue compression plays an important role since reducing the breast thickness increases visibility. In this work, fabrication of hydrogel breast tissue phantoms with varying concentrations of polyvinyl alcohol (PVAL) is carried out to mimic breast fat and glandular tissue properties for compression study. The phantoms were subjected to compression to investigate the mechanical properties for varying PVAL concentrations. A 3D numerical model was developed for phantom tissue compression simulations. Simulated tissue compression results were compared with phantom measurements for model validation.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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…

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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%.

  18. 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.

  19. 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.

  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. 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%.

  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. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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)

  9. 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

  10. 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)

  11. 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.

  12. 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.

  13. 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}.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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

  20. 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

  1. 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.…

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  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. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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…

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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).

  8. 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).

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  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. 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.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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].

  5. 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.

  6. 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.

  7. 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…

  8. 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.

  9. 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.

  10. 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)

  11. 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.

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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).

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Kinetics Modeling of Cancer Immunology.

    DTIC Science & Technology

    1986-05-09

    CANCER IMMUNOLOGY -1 DTICS ELECTED SEP 9 8 UNITED STATES NAVAL ACADEMY ANNAPOLIS, MARYLAND V ,1986 %,e docment ha le approved for public A." I and sale...1986 4. TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVERED KINETICS MODELING OF CANCER IMMUNOLOGY Final: 1985/1986 6. PERFORMING ORG. REPORT...137 (1986) "Kinetics Modeling of Cancer Immunology " A Trident Scholar Project Report by Midn I/C Scott Helmers, Class of 1986 United States Naval

  3. 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.

  4. 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.

  5. 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).

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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…

  16. 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)

  17. 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

  18. 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…

  19. 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

  20. 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)

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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)

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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).

  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

    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).

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. Spectral method for a kinetic swarming model

    DOE PAGES

    Gamba, Irene M.; Haack, Jeffrey R.; Motsch, Sebastien

    2015-04-28

    Here we present the first numerical method for a kinetic description of the Vicsek swarming model. The kinetic model poses a unique challenge, as there is a distribution dependent collision invariant to satisfy when computing the interaction term. We use a spectral representation linked with a discrete constrained optimization to compute these interactions. To test the numerical scheme we investigate the kinetic model at different scales and compare the solution with the microscopic and macroscopic descriptions of the Vicsek model. Lastly, we observe that the kinetic model captures key features such as vortex formation and traveling waves.

  19. The Relationship between Stoichiometry and Kinetics Revisited

    NASA Astrophysics Data System (ADS)

    Lee, Jim Y.

    2001-09-01

    Toby presented relations between concentrations of reaction participants in network reactions, obtained from kinetic considerations (rate laws) (J. Chem. Educ. 2000, 77, 188). The approach relies on the supposition of a reaction mechanism, the specification of the detailed kinetics for each elementary step, and mathematical simplifications by pseudo-steady-state approximation or prior equilibrium. However, the same results can be obtained more directly from material balance and reaction stoichiometry without any detailed information on chemical kinetics. This mirrors the often observed independence between stoichiometry and kinetics in most reactions of practical importance.

  20. The Kinetic Drawing System: A Review and Integration of the Kinetic Family and School Drawing Techniques.

    ERIC Educational Resources Information Center

    Knoff, Howard M.; Prout, H. Thompson

    1985-01-01

    Presents the Kinetic Drawing System as a logical integration of the Kinetic Family Drawing and Kinetic School Drawing techniques. Reviews the literature of these two projective techniques and provides a rationale and process toward their combination into a single approach. (LLL)

  1. Dissolution Kinetics of Alumina Calcine

    SciTech Connect

    Batcheller, Thomas Aquinas

    2001-09-01

    Dissolution kinetics of alumina type non-radioactive calcine was investigated as part of ongoing research that addresses permanent disposal of Idaho High Level Waste (HLW). Calcine waste was produced from the processing of nuclear fuel at the Idaho Nuclear Technology and Engineering Center (INTEC). Acidic radioactive raffinates were solidified at ~500°C in a fluidized bed reactor to form the dry granular calcine material. Several Waste Management alternatives for the calcine are presented in the Idaho High Level Waste Draft EIS. The Separations Alternative addresses the processing of the calcine so that the HLW is ready for removal to a national geological repository by the year 2035. Calcine dissolution is the key front-end unit operation for the separations alternative.

  2. Kinetic features of breunnerite decarbonization

    NASA Astrophysics Data System (ADS)

    Vusikhis, A. S.; Gulyaeva, R. I.; Leont'ev, L. I.; Ovchinnikova, L. A.; Selivanov, E. N.

    2016-09-01

    The decarbonization of breunnerite from talc waste is analyzed by thermogravimetry. The temperatures of thermal effects are determined, and kinetic models for the process are proposed to describe the mechanism of breunnerite decomposition. The unit cell parameters of breunnerite (Mg x Fe1- x )CO3 and the product of its decomposition, iron-magnesium oxide (Mg,Fe)O, are calculated. The apparent activation energies E a of the decomposition are calculated using the Ozawa-Flynn-Wall and Kissenger model-free methods and the Avrami-Erofeev one-step model. Depending on the chosen model, the values of E a range within 180-185 kJ/mol. The conditions of breunnerite roasting for the subsequent use of the obtained material in metallurgical processes are substantiated.

  3. Modelling reaction kinetics inside cells

    PubMed Central

    Grima, Ramon; Schnell, Santiago

    2009-01-01

    In the past decade, advances in molecular biology such as the development of non-invasive single molecule imaging techniques have given us a window into the intricate biochemical activities that occur inside cells. In this article we review four distinct theoretical and simulation frameworks: (1) non-spatial and deterministic, (2) spatial and deterministic, (3) non-spatial and stochastic and (4) spatial and stochastic. Each framework can be suited to modelling and interpreting intracellular reaction kinetics. By estimating the fundamental length scales, one can roughly determine which models are best suited for the particular reaction pathway under study. We discuss differences in prediction between the four modelling methodologies. In particular we show that taking into account noise and space does not simply add quantitative predictive accuracy but may also lead to qualitatively different physiological predictions, unaccounted for by classical deterministic models. PMID:18793122

  4. The origins of enzyme kinetics.

    PubMed

    Cornish-Bowden, Athel

    2013-09-02

    The equation commonly called the Michaelis-Menten equation is sometimes attributed to other authors. However, although Victor Henri had derived the equation from the correct mechanism, and Adrian Brown before him had proposed the idea of enzyme saturation, it was Leonor Michaelis and Maud Menten who showed that this mechanism could also be deduced on the basis of an experimental approach that paid proper attention to pH and spontaneous changes in the product after formation in the enzyme-catalysed reaction. By using initial rates of reaction they avoided the complications due to substrate depletion, product accumulation and progressive inactivation of the enzyme that had made attempts to analyse complete time courses very difficult. Their methodology has remained the standard approach to steady-state enzyme kinetics ever since.

  5. Vitamin E kinetics in sheep.

    PubMed

    Hidiroglou, M; Karpinski, K

    1987-07-01

    1. Kinetics of physiological doses of D-alpha-[5-Me-3H]tocopherol (200 microCi) administered to twenty-four sheep were studied using one of four routes: intravenous, oral (capsules), intraruminal and intramuscular. 2. Blood samples were withdrawn from the jugular vein periodically for 96 h after the intravenous and oral administrations, for 168 h after the intraruminal administration and for 216 h after the intramuscular administration. 3. The study indicated that the biological availability of alpha-tocopherol followed the order intravenous greater than intramuscular greater than oral greater than intraruminal. 4. The rate of elimination was in the order intravenous greater than oral greater than intraruminal approximately intramuscular. 5. The intravenous route was fitted with a three-compartment model, whereas the other routes exhibited a good fit for either a one- or two-compartment model.

  6. Kinetic modelling of mitochondrial translation.

    PubMed

    Korla, Kalyani; Mitra, Chanchal K

    2014-01-01

    Mitochondrial genome contains 13 protein coding genes, all being part of the oxidative phosphorylation complexes. The process of translation of these protein coding mRNAs in mitochondrial matrix is a good miniature model of translation in cytoplasm. In this work, we have simulated three phases of mitochondrial translation viz. initiation, elongation and termination (including ribosome recycling). The kinetic equations for these phases have been deduced based on the information available in literature. Various factors involved in the process have been included explicitly. Kinetic simulation was done using Octave, open source software. Scripts were written individually for each phase. Initiation begins with mitoribosome, mRNA, fMet-tRNA and initiation factors. The final product of the initiation script, the initiation complex, was introduced as the start point in the successive step, i.e. elongation. Elongation is a particular extensive process where the various aminoacyl-tRNAs already present in the matrix check for matching with the triplet codon in A-site of mitoribosome. This script consists of two parts: one with the time behaviour of the factors involved in the molecular process (using ordinary differential equation solver) and the other including the reading of triplet codon on the mRNA and incorporating the corresponding aminoacyl-tRNA, and then at each step elongating the peptide chain (using loops and conditions). The peptide chain thus formed in the elongation step (in the loops and conditions segment) was released in the termination step. This was followed by mitoribosome recycling where the mitoribosome reached the native state and was ready for the next cycle of translation.

  7. Algorithms, modelling and VO₂ kinetics.

    PubMed

    Capelli, Carlo; Carlo, Capelli; Cautero, Michela; Michela, Cautero; Pogliaghi, Silvia; Silvia, Pogliaghi

    2011-03-01

    This article summarises the pros and cons of different algorithms developed for estimating breath-by-breath (B-by-B) alveolar O(2) transfer (VO 2A) in humans. VO 2A is the difference between O(2) uptake at the mouth and changes in alveolar O(2) stores (∆ VO(2s)), which for any given breath, are equal to the alveolar volume change at constant FAO2/FAiO2 ∆VAi plus the O(2) alveolar fraction change at constant volume [V Ai-1(F Ai - F Ai-1) O2, where V (Ai-1) is the alveolar volume at the beginning of a breath. Therefore, VO 2A can be determined B-by-B provided that V (Ai-1) is: (a) set equal to the subject's functional residual capacity (algorithm of Auchincloss, A) or to zero; (b) measured (optoelectronic plethysmography, OEP); (c) selected according to a procedure that minimises B-by-B variability (algorithm of Busso and Robbins, BR). Alternatively, the respiratory cycle can be redefined as the time between equal FO(2) in two subsequent breaths (algorithm of Grønlund, G), making any assumption of V (Ai-1) unnecessary. All the above methods allow an unbiased estimate of VO2 at steady state, albeit with different precision. Yet the algorithms "per se" affect the parameters describing the B-by-B kinetics during exercise transitions. Among these approaches, BR and G, by increasing the signal-to-noise ratio of the measurements, reduce the number of exercise repetitions necessary to study VO2 kinetics, compared to A approach. OEP and G (though technically challenging and conceptually still debated), thanks to their ability to track ∆VO(2s) changes during the early phase of exercise transitions, appear rather promising for investigating B-by-B gas exchange.

  8. Phenanthrene biodegradation kinetics in unsaturated soils

    SciTech Connect

    Johnson, C.R.; Scow, K.M.

    1995-12-31

    Organic compounds when sorbed to soil solids are thought to be unavailable to soil microorganisms. The biodegradation kinetics of sorbed chemicals should thus be influenced by sorption/desorption processes as well as by the metabolic capacities of soil microbes. In the research, phenanthrene, a hydrophobic polyaromatic hydrocarbon, was used as a model compound to investigate the biodegradation kinetics of strongly sorbing organic compounds in soil. Biodegradation kinetics for phenanthrene in seven soils with moisture contents near field capacity were measured during a six and one half month experiment. Phenanthrene biodegradation rates initially increased in all soils and then declined. The declining portion of the biodegradation rate versus time plots exhibited either first order or biphasic kinetics. Both first order and biphasic kinetics are consistent with models which link microbial degradation to substrate sorption/desorption from equilibrium and kinetically controlled sorption sites. No single rate constant or analytical expression adequately captured the complexity of the observed biodegradation rates. This result is again consonant with a process derived from coupled biological and physical systems. Biodegradation kinetics were quantified using a combination of fitted and descriptive parameters. Significant correlations exist between several of the descriptive parameters. The correlations observed between descriptive biodegradation parameters mirror correlations expected from the hypothesized underlying biological process and help evince the influence this underlying process exerts on observed biodegradation kinetics.

  9. A Comprehensive Enzyme Kinetic Exercise for Biochemistry

    ERIC Educational Resources Information Center

    Barton, Janice S.

    2011-01-01

    This article describes a comprehensive treatment of experimental enzyme kinetics strongly coupled to electronic data acquisition and use of spreadsheets to organize data and perform linear and nonlinear least-squares analyses, all in a manner that promotes development of important reasoning skills. Kinetic parameters are obtained for the stable…

  10. A Kinetic Chain Approach for Shoulder Rehabilitation

    PubMed Central

    McMullen, John; Uhl, Timothy L.

    2000-01-01

    Objective: To introduce an approach to shoulder rehabilitation that integrates the kinetic chain throughout the rehabilitation program while providing the theoretical rationale for this program. Background: The focus of a typical rehabilitation program is to identify and treat the involved structures. However, in activities of sport and daily life, the body does not operate in isolated segments but rather works as a dynamic unit. Recently, rehabilitation programs have emphasized closed kinetic chain exercises, core-stabilization exercises, and functional programs. These components are implemented as distinct entities and are used toward the end of the rehabilitation program. Description: Kinetic chain shoulder rehabilitation incorporates the kinetic link biomechanical model and proximal-to-distal motor-activation patterns with proprioceptive neuromuscular facilitation and closed kinetic chain exercise techniques. This approach focuses on movement patterns rather than isolated muscle exercises. Patterns sequentially use the leg, trunk, and scapular musculature to activate weakened shoulder musculature, gain active range of motion, and increase strength. The paradigm of kinetic chain shoulder rehabilitation suggests that functional movement patterns and closed kinetic chain exercises should be incorporated throughout the rehabilitation process. Clinical Advantages: The exercises in this approach are consistent with biomechanical models, apply biomechanical and motor control theory, and work toward sport specificity. The exercises are designed to stimulate weakened tissue by motion and force production in the adjacent kinetic link segments. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6.Figure 7.Figure 8. PMID:16558646

  11. Microcomputer Simulation of Enzyme Kinetic Behaviour.

    ERIC Educational Resources Information Center

    Gill, R. A.

    1984-01-01

    Describes a program which simulates the kinetic behavior of a "typical" enzyme. Program objectives, background to the kinetic model used in the simulation, major program features, typical results obtained, and a note on the availability of the program (written in BASIC for Commodore microcomputer) are included. (JN)

  12. Kinetics of bulk crystallisation of supercooled melt

    NASA Astrophysics Data System (ADS)

    Chernov, A. A.; Pil'nik, A. A.

    2016-10-01

    The exact solution that fully describes the kinetics of the growth of a spherical crystal in supercooled melt is found. The kinetic model of nucleation-mediated crystallization is presented. It correctly takes into account the change in supercooling of the initial phase in the process of formation and evolution of a new phase.

  13. Enhancing Thai Students' Learning of Chemical Kinetics

    ERIC Educational Resources Information Center

    Chairam, Sanoe; Somsook, Ekasith; Coll, Richard K.

    2009-01-01

    Chemical kinetics is an extremely important concept for introductory chemistry courses. The literature suggests that instruction in chemical kinetics is often teacher-dominated at both the secondary school and tertiary levels, and this is the case in Thailand--the educational context for this inquiry. The work reported here seeks to shift students…

  14. Chemical kinetics and oil shale process design

    SciTech Connect

    Burnham, A.K.

    1993-07-01

    Oil shale processes are reviewed with the goal of showing how chemical kinetics influences the design and operation of different processes for different types of oil shale. Reaction kinetics are presented for organic pyrolysis, carbon combustion, carbonate decomposition, and sulfur and nitrogen reactions.

  15. Microwave radiometry for cement kiln temperature measurements.

    PubMed

    Stephan, Karl D; Wang, Lingyun; Ryza, Eric

    2007-01-01

    The maximum temperature inside a cement kiln is a critical operating parameter, but is often difficult or impossible to measure. We present here the first data that show a correlation between cement kiln temperature measured using a microwave radiometer and product chemistry over an eight-hour period. The microwave radiometer senses radiation in the 12-13 GHz range and has been described previously [Stephan and Pearce (2002), JMPEE 37: 112-124].

  16. Broad band airborne water vapor radiometry

    NASA Astrophysics Data System (ADS)

    Kuhn, Peter M.

    An infrared radiometer with a pass band of 280 to 520 cm-1 (35.7 to 19.2 µm) is employed on the NASA Ames Research Center U-2 and C-141A aircraft in the measurement of water vapor burden in the upper troposphere and stratosphere. Coincidentally with altitude changes the water vapor mass mixing ratio is also inferred by observing the change in optical depth over a known vertical distance. Data from the December 1980 U-2 Water Vapor Exchange Experiment over the Panama Canal Zone adds to the concept that overshooting cumulonimbus towers “moisten” the lower stratosphere. The average mass mixing ratio in close proximity to or above such towers ranges from 3.5 to 5.0 parts per million above 18 km while the average background mass mixing ratio is only 2.9 parts per million. Generally the lowest background mixing ratios, averaging 2.6 parts per million occurred in the 18 to 21 km layer. For the same levels background Panama mass mixing ratios averaged from 1.0 to 3.0 parts per million higher than in middle latitudes.

  17. Atmospheric scattering corrections to solar radiometry

    NASA Technical Reports Server (NTRS)

    Box, M. A.; Deepak, A.

    1979-01-01

    Whenever a solar radiometer is used to measure direct solar radiation, some diffuse sky radiation invariably enters the detector's field of view along with the direct beam. Therefore, the atmospheric optical depth obtained by the use of Bouguer's transmission law (also called Beer-Lambert's law), that is valid only for direct radiation, needs to be corrected by taking account of the scattered radiation. This paper discusses the correction factors needed to account for the diffuse (i,e., singly and multiply scattered) radiation and the algorithms developed for retrieving aerosol size distribution from such measurements. For a radiometer with a small field of view (half-cone angle of less than 5 deg) and relatively clear skies (optical depths less than 0.4), it is shown that the total diffuse contribution represents approximately 1% of the total intensity.

  18. Fast Radiometry Guided Fusion of Disparity Images

    NASA Astrophysics Data System (ADS)

    Schmid, Stephan; Fritsch, Dieter

    2016-06-01

    Previous work on disparity map fusion has mostly focused on geometric or statistical properties of disparity maps. Since failure of stereo algorithms is often consistent in many frames of a scene, it cannot be detected by such methods. Instead, we propose to use radiometric information from the original camera images together with externally supplied camera pose information to detect mismatches. As radiometric information is local information, the computations in the proposed algorithm for disparity fusion can be decoupled and parallelized to a very large degree, which allows us to easily achieve real-time performance.

  19. Physical Basis And Technology Of Microwave Radiometry

    NASA Astrophysics Data System (ADS)

    Mamouni, A.; N'Guven, D. D.; Robillard, M.; Chive, M.; Leroy, Y.

    1980-05-01

    Thermal noise detection in microwave frequency range can lead to a non invasive subcutaneous temperature measurement in the living tissues. Several clinical aoplications are mentioned (cancer detection, brain temperature measurements, ergonomics). First experiments, and computations on thermal models show a possible achievement of a new method concerning a thermal pattern recognition.

  20. Radiometry of near-earth asteroids

    NASA Technical Reports Server (NTRS)

    Veeder, G. J.; Hanner, M. S.; Matson, D. L.; Tedesco, E. F.; Lebofsky, L. A.

    1989-01-01

    Infrared photometry is reported for 22 Aten, Apollo, and Amor asteroids. Thermal models are used to derive the corresponding radiometric albedos and diameters. Several of these asteroids appear to have surfaces of relatively high thermal inertia due to the exposure of bare rock or a coarse regolith. The Apollo asteroid 3103, 1982 BB, is recognized as class E. The Jupiter-crossing Amor asteroid 3552, 1983 SA, is confirmed as class D, but low albedos remain rare for near-earth asteroids.

  1. Radiometry of near-earth asteroids.

    PubMed

    Veeder, G J; Hanner, M S; Matson, D L; Tedesco, E F; Lebofsky, L A; Tokunaga, A T

    1989-04-01

    We report 10 micrometers infrared photometry for 22 Aten, Apollo, and Amor asteroids. Thermal models are used to derive the corresponding radiometric albedos and diameters. Several of these asteroids appear to have surfaces of relatively high thermal inertia due to the exposure of bare rock or a coarse regolith. The Apollo asteroid 3103, 1982 BB, is recognized as class E. The Jupiter-crossing Amor asteroid 3552, 1983 SA, is confirmed as class D, but low albedos remain rare for near-Earth asteroids.

  2. Atmospheric Correction for Satellite Ocean Color Radiometry

    NASA Technical Reports Server (NTRS)

    Mobley, Curtis D.; Werdell, Jeremy; Franz, Bryan; Ahmad, Ziauddin; Bailey, Sean

    2016-01-01

    This tutorial is an introduction to atmospheric correction in general and also documentation of the atmospheric correction algorithms currently implemented by the NASA Ocean Biology Processing Group (OBPG) for processing ocean color data from satellite-borne sensors such as MODIS and VIIRS. The intended audience is graduate students or others who are encountering this topic for the first time. The tutorial is in two parts. Part I discusses the generic atmospheric correction problem. The magnitude and nature of the problem are first illustrated with numerical results generated by a coupled ocean-atmosphere radiative transfer model. That code allow the various contributions (Rayleigh and aerosol path radiance, surface reflectance, water-leaving radiance, etc.) to the topof- the-atmosphere (TOA) radiance to be separated out. Particular attention is then paid to the definition, calculation, and interpretation of the so-called "exact normalized water-leaving radiance" and its equivalent reflectance. Part I ends with chapters on the calculation of direct and diffuse atmospheric transmittances, and on how vicarious calibration is performed. Part II then describes one by one the particular algorithms currently used by the OBPG to effect the various steps of the atmospheric correction process, viz. the corrections for absorption and scattering by gases and aerosols, Sun and sky reflectance by the sea surface and whitecaps, and finally corrections for sensor out-of-band response and polarization effects. One goal of the tutorial-guided by teaching needs- is to distill the results of dozens of papers published over several decades of research in atmospheric correction for ocean color remote sensing.

  3. High dynamic range infrared radiometry and imaging

    NASA Technical Reports Server (NTRS)

    Coon, Darryl D.; Karunasiri, R. P. G.; Bandara, K. M. S. V.

    1988-01-01

    The use is described of cryogenically cooled, extrinsic silicon infrared detectors in an unconventional mode of operation which offers an unusually large dynamic range. The system performs intensity-to-frequency conversion at the focal plane via simple circuits with very low power consumption. The incident IR intensity controls the repetition rate of short duration output pulses over a pulse rate dynamic range of about 10(6). Theory indicates the possibility of monotonic and approx. linear response over the full dynamic range. A comparison between the theoretical and the experimental results shows that the model provides a reasonably good description of experimental data. Some measurements of survivability with a very intense IR source were made on these devices and found to be very encouraging. Evidence continues to indicate that some variations in interpulse time intervals are deterministic rather than probabilistic.

  4. Snow water equivalent determination by microwave radiometry

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.; Foster, J. L.; Hall, D. K.; Rango, A.; Hartline, B. K.

    1981-01-01

    One of the most important parameters for accurate snowmelt runoff prediction is snow water equivalent (SWE) which is contentionally monitored using observations made at widely scattered points in or around specific watersheds. Remote sensors which provide data with better spatial and temporal coverage can be used to improve the SWE estimates. Microwave radiation, which can penetrate through a snowpack, may be used to infer the SWE. Calculations made from a microscopic scattering model were used to simulate the effect of varying SWE on the microwave brightness temperature. Data obtained from truck mounted, airborne and spaceborne systems from various test sites were studied. The simulated SWE compares favorable with the measured SWE. In addition, whether the underlying soil is frozen or thawed can be discriminated successfully on the basis of the polarization of the microwave radiation.

  5. Kinetic advantage of controlled intermediate nuclear fusion

    SciTech Connect

    Guo Xiaoming

    2012-09-26

    The dominated process of controlled fusion is to let nuclei gain enough kinetic energy to overcome Coulomb barrier. As a result, a fusion scheme can consider two factors in its design: to increase kinetic energy of nuclei and to alter the Coulomb barrier. Cold Fusion and Hot fusion are all one-factor schemes while Intermediate Fusion is a twofactors scheme. This made CINF kinetically superior. Cold Fusion reduces deuteron-deuteron distance, addressing Coulomb barrier, and Hot Fusion heat up plasma into extreme high temperature, addressing kinetic energy. Without enough kinetic energy made Cold Fusion skeptical. Extreme high temperature made Hot Fusion very difficult to engineer. Because CIFN addresses both factors, CIFN is a more promising technique to be industrialized.

  6. Center for Environmental Kinetic Synthesis (CEKA)

    SciTech Connect

    Lichtner, Peter .

    2006-06-01

    CEKA, as an Environmental Molecular Science Institute, is a joint research initiative of the National Science Foundation and U.S. Department of Energy, Biological and Environmental Research (BER). DOE collaborators are from DOE facilities at Los Alamos National Lab, Lawrence Berkeley National Lab and Pacific Northwest National Lab. The chief goals for CEKA are to 1) collect and synthesize molecular-level kinetic data into a coherent framework that can be used to predict time evolution of environmental processes over a range of temporal and spatial scales; 2) train a cohort of talented and diverse students to work on kinetic problems at multiple scales; 3) develop and promote the use of new experimental techniques in environmental kinetics; 4) develop and promote the use of new modeling tools to conceptualize reaction kinetics in environmental systems; and 5) communicate our understanding of issues related to environmental kinetics and issues of scale to the broader scientific community and to the public.

  7. Adsorption studies of molasse's wastewaters on activated carbon: modelling with a new fractal kinetic equation and evaluation of kinetic models.

    PubMed

    Figaro, S; Avril, J P; Brouers, F; Ouensanga, A; Gaspard, S

    2009-01-30

    Adsorption kinetic of molasses wastewaters after anaerobic digestion (MSWD) and melanoidin respectively on activated carbon was studied at different pH. The kinetic parameters could be determined using classical kinetic equations and a recently published fractal kinetic equation. A linear form of this equation can also be used to fit adsorption data. Even with lower correlation coefficients the fractal kinetic equation gives lower normalized standard deviation values than the pseudo-second order model generally used to fit adsorption kinetic data, indicating that the fractal kinetic model is much more accurate for describing the kinetic adsorption data than the pseudo-second order kinetic model.

  8. Experimental Study of U(VI) Release Kinetics from Aquifer Sediments from a Former Uranium Mill Tailings Site (Rifle, Colorado, USA)

    NASA Astrophysics Data System (ADS)

    Hyun, S.; Campbell, K. M.; Hayes, K. F.; Davis, J. A.

    2007-12-01

    Uranium(VI) release kinetics from aquifer sediments from a former uranium mill tailings site in Rifle, Colorado was studied to understand uranium distribution within the sediments. The sediments were sampled at depths of 3.5-3.8 m in December 2004. The samples were air-dried, sieved, and the <2 mm fraction was collected and used in this study. Total uranium content in the sediments, determined by gamma-radiometry, was 4.1 μg/g sediment. The labile fraction of U(VI) in the sediments was determined using carbonate/bicarbonate extractions, which should cause complete desorption of U(VI) in the absence of mass transfer limitations. Carbonate/bicarbonate extraction of the sediments showed very slow release kinetics, with only 12 % of the labile U(VI) in the sediments being released during the first 96 hours of extraction. This is much less than found in a previous study at a different mill tailings site (Naturita, Colorado), in which more than 80 % of labile U(VI) was released during the same period of extraction. Up to two months of carbonate/bicarbonate extraction released 1 μg U(VI) per gram of Rifle sediment, which is 25 % of the total U in the sediment. Extraction with an artificial groundwater prepared to simulate the field groundwater chemistry showed 0.26 μg U/g sediment was released during the initial 94 hours of extraction, with a gradual increase of released U(VI) with time, while other major and minor elements (except Si) rapidly reached steady-state concentrations during the first few hours of reaction. Two hypotheses are under consideration to explain the slow U(VI) release kinetics: 1) colloidal clay fraction particles cementing larger grains of the sediments are creating nanoscale interparticle pores that act as a diffusion barrier to U(VI) desorption, and 2) a U(IV) solid phase exists whose oxidation and dissolution control the U(VI) release rate. To test the hypotheses, oxidation and extraction of the sediments have been conducted using oxidants

  9. Calcium Kinetics During Space Flight

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; OBrien, K. O.; Abrams, S. A.; Wastney, M. E.

    2005-01-01

    Bone loss during space flight is one of the most critical challenges to astronaut health on space exploration missions. Defining the time course and mechanism of these changes will aid in developing means to counteract bone loss during space flight, and will have relevance for other clinical situations that impair weight-bearing activity. Bone health is a product of the balance between bone formation and bone resorption. Early space research could not clearly identify which of these was the main process altered in bone loss, but identification of the collagen crosslinks in the 1990s made possible a clear understanding that the impact of space flight was greater on bone resorption, with bone formation being unchanged or only slightly decreased. Calcium kinetics data showed that bone resorption was greater during flight than before flight (668 plus or minus 130 vs. 427 plus or minus 153 mg/d, p less than 0.001), and clearly documented that true intestinal calcium absorption was lower during flight than before flight (233 plus or minus 87 vs. 460 plus or minus 47 mg/d, p less than 0.01). Weightlessness had a detrimental effect on the balance in bone turnover: the difference between daily calcium balance during flight (-234 plus or minus 102 mg/d) and calcium balance before flight (63 plus or minus 75 mg/d) approached 300 mg/d (p less than 0.01). These data demonstrate that the bone loss that occurs during space flight is a consequence of increased bone resorption and decreased intestinal calcium absorption. Examining the changes in bone and calcium homeostasis in the initial days and weeks of space flight, as well as at later times on missions longer than 6 months, is critical to understanding the nature of bone adaptation to weightlessness. To increase knowledge of these changes, we studied bone adaptation to space flight on the 16-day Space Shuttle Columbia (STS-107) mission. When the brave and talented crew of Columbia were lost during reentry on the tragic morning

  10. Kinetic mean-field theories

    NASA Astrophysics Data System (ADS)

    Karkheck, John; Stell, George

    1981-08-01

    A kinetic mean-field theory for the evolution of the one-particle distribution function is derived from maximizing the entropy. For a potential with a hard-sphere core plus tail, the resulting theory treats the hard-core part as in the revised Enskog theory. The tail, weighted by the hard-sphere pair distribution function, appears linearly in a mean-field term. The kinetic equation is accompanied by an entropy functional for which an H theorem was proven earlier. The revised Enskog theory is obtained by setting the potential tail to zero, the Vlasov equation is obtained by setting the hard-sphere diameter to zero, and an equation of the Enskog-Vlasov type is obtained by effecting the Kac limit on the potential tail. At equilibrium, the theory yields a radial distribution function that is given by the hard-sphere reference system and thus furnishes through the internal energy a thermodynamic description which is exact to first order in inverse temperature. A second natural route to thermodynamics (from the momentum flux which yields an approximate equation of state) gives somewhat different results; both routes coincide and become exact in the Kac limit. Our theory furnishes a conceptual basis for the association in the heuristically based modified Enskog theory (MET) of the contact value of the radial distribution function with the ''thermal pressure'' since this association follows from our theory (using either route to thermodynamics) and moreover becomes exact in the Kac limit. Our transport theory is readily extended to the general case of a soft repulsive core, e.g., as exhibited by the Lennard-Jones potential, via by-now-standard statistical-mechanical methods involving an effective hard-core potential, thus providing a self-contained statistical-mechanical basis for application to such potentials that is lacking in the standard versions of the MET. We obtain very good agreement with experiment for the thermal conductivity and shear viscosity of several

  11. Growth Kinetics in Epitaxial Growth

    NASA Astrophysics Data System (ADS)

    Hessinger, Uwe

    Growth kinetics in heteroepitaxial growth are related to the nucleation and growth of atomic-height islands during the deposition of a material on a dissimilar substrate. Experimental measurements of the initial morphology of CaF_2 films deposited on Si(111) substrates were performed. These measurements consisted of photoemission spectroscopy and diffraction, which give sub-nanometer scale information averaged over the entire sample, and plan-view transmission electron microscopy, which gives localized information on a scale of several nanometers. These results, combined with others in the literature, revealed four distinct growth morphologies dependent on the deposition rate, substrate temperature and spacing between atomic-height steps on the surface, two of which had not been previously explained. A model based on two extant theories of homoepitaxial growth kinetics was developed to explain the different observed growth morphologies for the heteroepitaxial system CaF_2/Si(111). The first theory deals with whether the initial nucleation will occur at substrate steps or through adatom collisions on flat terraces, while the second deals with the nucleation of subsequent layers as these initial atomic islands increase in size. In extending these theories to heteroepitaxy, very different rates of upper-layer nucleation for the different size islands that nucleated at steps and on terraces are predicted. By applying this theory to CaF_2/Si(111), the diffusion barriers for CaF_2 molecule migration both on the reacted Si-Ca-F interface layer and on subsequent CaF_2 layers was extracted. The four different growth morphologies are explained within a common framework. The theory is quite general, and should apply to most heteroepitaxial systems. These theories were extended to predict a means by which the upper-layer nucleation may be inhibited while the underlying layer is completed. This method involves initiating the growth at conditions favoring many, small islands on

  12. Kinetic Proofreading of Cytoskeletal Structures

    NASA Astrophysics Data System (ADS)

    Swanson, Douglas; Wingreen, Ned

    2010-03-01

    Cytoskeletal polymer dynamics play a role in cellular processes as varied as reproduction, locomotion, and intracellular transport. Microtubules are cytoskeletal biopolymers that grow by accumulating tubulin subunits bound to guanosine triphosphate (GTP). The subunits hydrolyze GTP to guanosine diphosphate (GDP), causing a conformational change in the protein that destabilizes the microtubule. GDP-bound subunits tend to depolymerize, leading to stochastic microtubule disassembly in a process known as dynamic instability. Over time polymerization and depolymerization come to steady state, leading to a local steady-state concentration of tubulin subunits. This may be viewed as a kind of ``kinetic proofreading,'' in which the system consumes energy actively to ``proofread'' the steady-state subunit concentration. We suggest that the same mechanism could also ``proofread'' between different cytoskeletal structures. For example, we show that a small free-energy difference between two polymer orientations, combined with dynamic instability, can strongly drive the system towards the lower free-energy state. This might help to explain the long-time stability of many cytoskeletal structures despite the short-time rapid turnover of the individual subunits.

  13. Aerodynamics of Unsteady Sailing Kinetics

    NASA Astrophysics Data System (ADS)

    Keil, Colin; Schutt, Riley; Borshoff, Jennifer; Alley, Philip; de Zegher, Maximilien; Williamson, Chk

    2015-11-01

    In small sailboats, the bodyweight of the sailor is proportionately large enough to induce significant unsteady motion of the boat and sail. Sailors use a variety of kinetic techniques to create sail dynamics which can provide an increment in thrust, thereby increasing the boatspeed. In this study, we experimentally investigate the unsteady aerodynamics associated with two techniques, ``upwind leech flicking'' and ``downwind S-turns''. We explore the dynamics of an Olympic class Laser sailboat equipped with a GPS, IMU, wind sensor, and camera array, sailed expertly by a member of the US Olympic team. The velocity heading of a sailing boat is oriented at an apparent wind angle to the flow. In contrast to classic flapping propulsion, the heaving of the sail section is not perpendicular to the sail's motion through the air. This leads to heave with components parallel and perpendicular to the incident flow. The characteristic motion is recreated in a towing tank where the vortex structures generated by a representative 2-D sail section are observed using Particle Image Velocimetry and the measurement of thrust and lift forces. Amongst other results, we show that the increase in driving force, generated due to heave, is larger for greater apparent wind angles.

  14. Kinetics of DNA tile dimerization.

    PubMed

    Jiang, Shuoxing; Yan, Hao; Liu, Yan

    2014-06-24

    Investigating how individual molecular components interact with one another within DNA nanoarchitectures, both in terms of their spatial and temporal interactions, is fundamentally important for a better understanding of their physical behaviors. This will provide researchers with valuable insight for designing more complex higher-order structures that can be assembled more efficiently. In this report, we examined several spatial factors that affect the kinetics of bivalent, double-helical (DH) tile dimerization, including the orientation and number of sticky ends (SEs), the flexibility of the double helical domains, and the size of the tiles. The rate constants we obtained confirm our hypothesis that increased nucleation opportunities and well-aligned SEs accelerate tile-tile dimerization. Increased flexibility in the tiles causes slower dimerization rates, an effect that can be reversed by introducing restrictions to the tile flexibility. The higher dimerization rates of more rigid tiles results from the opposing effects of higher activation energies and higher pre-exponential factors from the Arrhenius equation, where the pre-exponential factor dominates. We believe that the results presented here will assist in improved implementation of DNA tile based algorithmic self-assembly, DNA based molecular robotics, and other specific nucleic acid systems, and will provide guidance to design and assembly processes to improve overall yield and efficiency.

  15. Pyrolysis kinetics of lignocellulosic materials

    SciTech Connect

    Balci, S.; Dogu, T.; Yuecel, H. . Dept. of Chemical Engineering)

    1993-11-01

    Pyrolysis kinetics of almond and hazelnut shells and beech wood were carried out using a thermogravimetric technique. Experiments were repeated for different final pyrolysis temperatures ranging from 300 to 850 C. Approximately 90% of the pyrolysis reactions were completed up to 450 C. The initial values of the activation energy of pyrolysis reaction were found to be around 22 kcal/mol for shells of almond and hazelnut. On the other hand, initial activation energy of beech wood pyrolysis was found as 29.4 kcal/mol. Results indicated that a first-order decomposition in terms of volatile content of the reactant showed good agreement with the data only at the initial stages of the reaction. The reaction rate constant was found to decrease with reaction extent due to the changes in the chemical and physical structure of the solid. Among several models proposed, a model which predicted an increase of activation energy with reaction extent gave the best agreement with the experimental data.

  16. The neurology of kinetic art.

    PubMed

    Zeki, S; Lamb, M

    1994-06-01

    All visual art must obey the laws of the visual system. The first law is that an image of the visual world is not impressed upon the retina, but assembled together in the visual cortex. Consequently, many of the visual phenomena traditionally attributed to the eye actually occur in the cortex. Among these is visual motion. The second law is that of the functional specialization of the visual cortex, by which we mean that separate attributes of the visual scene are processed in geographically separate parts of the visual cortex, before being combined to give a unified and coherent picture of the visual world. The third law is that the attributes that are separated, and separately processed, in the cerebral cortex are those which have primacy in vision. These are colour, form, motion and, possibly, depth. It follows that motion is an autonomous visual attribute, separately processed and therefore capable of being separately compromised after brain lesions. It is also one of the visual attributes that have primacy, just like form or colour or depth. We conclude that it is this separate visual attribute which those involved in kinetic art have tried to exploit, instinctively and physiologically, from which it follows that in their explorations artists are unknowingly exploring the organization of the visual brain though with techniques unique to them.

  17. Kinetics of DNA Tile Dimerization

    PubMed Central

    2015-01-01

    Investigating how individual molecular components interact with one another within DNA nanoarchitectures, both in terms of their spatial and temporal interactions, is fundamentally important for a better understanding of their physical behaviors. This will provide researchers with valuable insight for designing more complex higher-order structures that can be assembled more efficiently. In this report, we examined several spatial factors that affect the kinetics of bivalent, double-helical (DH) tile dimerization, including the orientation and number of sticky ends (SEs), the flexibility of the double helical domains, and the size of the tiles. The rate constants we obtained confirm our hypothesis that increased nucleation opportunities and well-aligned SEs accelerate tile–tile dimerization. Increased flexibility in the tiles causes slower dimerization rates, an effect that can be reversed by introducing restrictions to the tile flexibility. The higher dimerization rates of more rigid tiles results from the opposing effects of higher activation energies and higher pre-exponential factors from the Arrhenius equation, where the pre-exponential factor dominates. We believe that the results presented here will assist in improved implementation of DNA tile based algorithmic self-assembly, DNA based molecular robotics, and other specific nucleic acid systems, and will provide guidance to design and assembly processes to improve overall yield and efficiency. PMID:24794259

  18. Kinetic Modelling of Transcription Elongation

    NASA Astrophysics Data System (ADS)

    O'Maoileidigh, Daibhid; Tadigotla, Vasisht; Sengupta, Anirvan; Epshtein, Vitaly; Ebright, Richard; Nudler, Evgeny; Ruckenstein, Andrei

    2006-03-01

    Transcription is the first step in gene expression and it is at this stage that most of genetic regulation occurs. The enzyme RNA polymerase (RNAP) walks along DNA creating an RNA transcript at a highly non-uniform rate. We discuss how many non-intuitive features of the system may be experimentally and physically motivated and present first a model, which agrees qualitatively with a host of experimental evidence. We also examine intrinsic pauses where it is thought that the RNAP will move backwards along the DNA template without changing the length of the RNA transcript. We describe a simplified kinetic scheme for the recovery of intrinsic pauses with the same degree of predictive power as our thermodynamic model (presented separately). The separation of timescales between the movement of the RNAP and global changes in the RNA secondary structure is seen to be crucial for the function of RNAP. This is essentially a model of a Brownian ratchet where RNAP executes a 1D random walk in a sequence dependent potential over a range determined by the co-transcriptional RNA fold for each transcript length

  19. Selective neutrality and enzyme kinetics.

    PubMed

    Demetrius, L

    1997-10-01

    This article appeals to a recent theory of enzyme evolution to show that the properties, neutral or adaptive, which characterize the observed allelic variation in natural populations can be inferred from the functional parameters, substrate specificity, and reaction rate. This study delineates the following relations between activity variables, and the forces--adaptive or neutral--determining allelic variation: (1) Enzymes with broad substrate specificity: The observed polymorphism is adaptive; mutations in this class of enzymes can result in increased fitness of the organism and hence be relevant for positive selection. (2) Enzymes with absolute substrate specificity and diffusion-controlled rates: Observed allelic variation will be absolutely neutral; mutations in this class of enzymes will be either deleterious or have no effect on fitness. (3) Enzymes with absolute or group specificity and nondiffusion-controlled rates: Observed variation will be partially neutral; mutants which are selectively neutral may become advantageous under an appropriate environmental condition or different genetic background. We illustrate each of the relations between kinetic properties and evolutionary states with examples drawn from enzymes whose evolutionary dynamics have been intensively studied.

  20. Complex kinetics of fluctuating enzymes: phase diagram characterization of a minimal kinetic scheme.

    PubMed

    Min, Wei; Jiang, Liang; Xie, X Sunney

    2010-05-03

    Enzyme molecules are dynamic entities with stochastic fluctuation in both protein conformation and enzymatic activity. However, such a notion of fluctuating enzymes, best characterized by recent single-molecule experiments, was not considered in the classic Michaelis-Menten (MM) kinetic scheme. Here we incorporate the fluctuation concept into the reversible MM scheme, and solve analytically all the possible kinetics (i.e., substrate concentration dependent enzymatic velocity) for a minimal model of fluctuating enzymes. Such a minimal model is found to display a variety of distinct kinetic behaviors (phases) in addition to the classic MM kinetics; excess substrate inhibition, sigmoidal kinetics, and concave biphasic kinetics. We find that all these kinetic phases are interrelated and unified under the framework of fluctuating enzymes and can be adequately described by a phase diagram that consists of two master parameters. Functionally, substrate inhibition, sigmoidal kinetics, and convex biphasic phases exhibit positive cooperativity, whereas concave biphasic phases display negative cooperativity. Remarkably, all these complex kinetics are produced by fluctuating enzymes with single substrate binding site, but the two conformations are, therefore, fundamentally different from the classic MWC and KNF models that require multiple subunit or binding sites. This model also suggests that, for a given enzyme/substrate pair, the non-MM behaviors could undergo transitions among different kinetic phases induced by varying product concentrations, owing to the fundamental Haldane symmetry in the reversible MM scheme.

  1. Classical Antiferromagnetism in Kinetically Frustrated Electronic Models

    NASA Astrophysics Data System (ADS)

    Sposetti, C. N.; Bravo, B.; Trumper, A. E.; Gazza, C. J.; Manuel, L. O.

    2014-05-01

    We study, by means of the density matrix renormalization group, the infinite U Hubbard model—with one hole doped away from half filling—in triangular and square lattices with frustrated hoppings, which invalidate Nagaoka's theorem. We find that these kinetically frustrated models have antiferromagnetic ground states with classical local magnetization in the thermodynamic limit. We identify the mechanism of this kinetic antiferromagnetism with the release of the kinetic energy frustration, as the hole moves in the established antiferromagnetic background. This release can occur in two different ways: by a nontrivial spin Berry phase acquired by the hole, or by the effective vanishing of the hopping amplitude along the frustrating loops.

  2. Determining enzyme kinetics via isothermal titration calorimetry.

    PubMed

    Demarse, Neil A; Killian, Marie C; Hansen, Lee D; Quinn, Colette F

    2013-01-01

    Isothermal titration calorimetry (ITC) has emerged as a powerful tool for determining the thermodynamic properties of chemical or physical equilibria such as protein-protein, ligand-receptor, and protein-DNA binding interactions. The utility of ITC for determining kinetic information, however, has not been fully recognized. Methods for collecting and analyzing data on enzyme kinetics are discussed here. The step-by-step process of converting the raw heat output rate into the kinetic parameters of the Michaelis-Menten equation is explicitly stated. The hydrolysis of sucrose by invertase is used to demonstrate the capability of the instrument and method.

  3. Modeling of Reactor Kinetics and Dynamics

    SciTech Connect

    Matthew Johnson; Scott Lucas; Pavel Tsvetkov

    2010-09-01

    In order to model a full fuel cycle in a nuclear reactor, it is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by coupling fuel burnup equations with the kinetics equations. When the equations are solved simultaneously with a nonlinear equation solver, the end result is a code with the unique capability of modeling transients at any time during a fuel cycle.

  4. Kinetics of coal pyrolysis and devolatilization

    SciTech Connect

    Seery, D.J.; Freihaut, J.D.; Proscia, W.M.

    1991-01-01

    The objective of these coordinated experimental and modeling studies is to develop an improved understanding of the kinetics of coal devolatilization which are relevant to suspension firing of powdered coal. These fundamental kinetic studies address several topics related to an improved understanding of pulverized coal combustion and includes both homogeneous and hetergeneous reactions. The principal topics include: (a) the pyrolysis and devolatilization of coal; and (b) the formation of char. Research activities include small-scale experimentation, interpretation of experimental results in terms of mechanistic understanding and the development and validation of kinetic models of fundamental processes. 6 refs., 20 figs., 7 tabs.

  5. Liquefaction chemistry and kinetics: Hydrogen utilization studies

    SciTech Connect

    Rothenberger, K.S.; Warzinski, R.P.; Cugini, A.V.

    1995-12-31

    The objectives of this project are to investigate the chemistry and kinetics that occur in the initial stages of coal liquefaction and to determine the effects of hydrogen pressure, catalyst activity, and solvent type on the quantity and quality of the products produced. The project comprises three tasks: (1) preconversion chemistry and kinetics, (2) hydrogen utilization studies, and (3) assessment of kinetic models for liquefaction. The hydrogen utilization studies work will be the main topic of this report. However, the other tasks are briefly described.

  6. On the relationships between the Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, equilibrium chemistry approximation kinetics, and quadratic kinetics

    DOE PAGES

    Tang, J. Y.

    2015-12-01

    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 either of the two are often ambiguous. Here I show that these two kinetics are special approximations to the equilibrium chemistry approximation (ECA) kinetics, which is the first-order approximation to the quadratic kinetics that solves the equation of an enzyme–substrate complex exactly for a single-enzyme and single-substrate biogeochemical reaction with the law of mass action and the assumption of a quasi-steadymore » 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 show 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 deriving 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 underpredict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln [E]T of v with respect the total enzyme concentration [E]T, and persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln [S]T of v with respect to the total substrate concentration

  7. Kinetic effects in edge plasma: kinetic modeling for edge plasma and detached divertor

    NASA Astrophysics Data System (ADS)

    Takizuka, T.

    2017-03-01

    Detached divertor is considered a solution for the heat control in magnetic-confinement fusion reactors. Numerical simulations using the comprehensive divertor codes based on the plasma fluid modeling are indispensable for the design of the detached divertor in future reactors. Since the agreement in the results between detached-divertor experiments and simulations has been rather fair but not satisfactory, further improvement of the modeling is required. The kinetic effect is one of key issues for improving the modeling. Complete kinetic behaviors are able to be simulated by the kinetic modeling. In this paper at first, major kinetic effects in edge plasma and detached divertor are listed. One of the most powerful kinetic models, particle-in-cell (PIC) model, is described in detail. Several results of PIC simulations of edge-plasma kinetic natures are presented. Future works on PIC modeling and simulation for the deeper understanding of edge plasma and detached divertor are discussed.

  8. Kinetic versus Energetic Discrimination in Biological Copying

    NASA Astrophysics Data System (ADS)

    Sartori, Pablo; Pigolotti, Simone

    2013-05-01

    We study stochastic copying schemes in which discrimination between a right and a wrong match is achieved via different kinetic barriers or different binding energies of the two matches. We demonstrate that, in single-step reactions, the two discrimination mechanisms are strictly alternative and cannot be mixed to further reduce the error fraction. Close to the lowest error limit, kinetic discrimination results in a diverging copying velocity and dissipation per copied bit. On the other hand, energetic discrimination reaches its lowest error limit in an adiabatic regime where dissipation and velocity vanish. By analyzing experimentally measured kinetic rates of two DNA polymerases, T7 and Polγ, we argue that one of them operates in the kinetic and the other in the energetic regime. Finally, we show how the two mechanisms can be combined in copying schemes implementing error correction through a proofreading pathway.

  9. The Kinetics of Nitrogen Atom Recombination

    ERIC Educational Resources Information Center

    Brown, G. Ronald; Winkler, C. A.

    1977-01-01

    Describes a study of the kinetics of the recombination of nitrogen atoms in which concentration-time relations are determined directly by utilizing visual observations of emissions to make gas phase titrations of N atoms with NO. (MLH)

  10. Extracellular enzyme kinetics scale with resource availability

    EPA Science Inventory

    Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimi...

  11. The Early Development of Kinetic Theory.

    ERIC Educational Resources Information Center

    Whitaker, Robert D.

    1979-01-01

    A review of the work of Bernoulli and other early contributors to kinetic theory. One significant point is that the most outstanding work in this early period was done by a little-known Scotsman, John J. Waterston. (BB)

  12. Large kinetic power in FRII radio jets

    NASA Astrophysics Data System (ADS)

    Ito, Hirotaka; Kino, Motoki; Kawakatu, Nozomu; Isobe, Naoki; Yamada, Shoichi

    2007-10-01

    We investigate the total kinetic powers ( L j) and ages ( t age) of powerful jets of four FR II radio sources (Cygnus A, 3C 223, 3C 284, and 3C 219) by the detail comparison of the dynamical model of expanding cocoons with observed ones. It is found that these sources have quite large kinetic powers with the ratio of L j to the Eddington luminosity ( L Edd) resides in 0.02< L j/ L Edd<10. Reflecting the large kinetic powers, we also find that the total energy stored in the cocoon ( E c) exceed the energy derived from the minimum energy condition ( E min ): 2< E c/ E min <160. This implies that a large amount of kinetic power is carried by invisible components such as thermal leptons (electron and positron) and/or protons.

  13. A Course in Kinetics and Catalysis.

    ERIC Educational Resources Information Center

    Bartholomew, C. H.

    1981-01-01

    Describes a one-semester, three-credit hour course integrating the fundamentals of kinetics and the scientific/engineering principles of heterogeneous catalysis. Includes course outline, list of texts, background readings, and topical journal articles. (SK)

  14. The Kinetics of Isotopic Exchange Reactions.

    ERIC Educational Resources Information Center

    Logan, S. R.

    1990-01-01

    Discussed are the kinetic interactions of these chemical processes and the determination of the actual order of such reactions. Included are multiple exchange, catalytic exchange with deuterium, and depletion of the original substrate. (CW)

  15. Practical Enzyme Kinetics: A Biochemical Laboratory Experiment.

    ERIC Educational Resources Information Center

    Rowe, H. Alan; Brown, Morris

    1988-01-01

    Describes an experiment that provides a fundamental understanding of the kinetics of the enzyme papain. Discusses background, materials, procedures and results. Mentions analogous experiments that can be conducted with enzymatic contact-lens cleaning solutions. (CW)

  16. Practical steady-state enzyme kinetics.

    PubMed

    Lorsch, Jon R

    2014-01-01

    Enzymes are key components of most biological processes. Characterization of enzymes is therefore frequently required during the study of biological systems. Steady-state kinetics provides a simple and rapid means of assessing the substrate specificity of an enzyme. When combined with site-directed mutagenesis (see Site-Directed Mutagenesis), it can be used to probe the roles of particular amino acids in the enzyme in substrate recognition and catalysis. Effects of interaction partners and posttranslational modifications can also be assessed using steady-state kinetics. This overview explains the general principles of steady-state enzyme kinetics experiments in a practical, rather than theoretical, way. Any biochemistry textbook will have a section on the theory of Michaelis-Menten kinetics, including derivations of the relevant equations. No specific enzymatic assay is described here, although a method for monitoring product formation or substrate consumption over time (an assay) is required to perform the experiments described.

  17. Kinetic Alfvén Waves

    NASA Video Gallery

    In a kinetic Alfvén wave, some particles become trapped in the weak spots of the wave’s magnetic field and ride along with the wave as it moves through space.Credit: NASA Goddard's Scientific Vis...

  18. The early folding kinetics of apomyoglobin.

    PubMed Central

    Pappu, R. V.; Weaver, D. L.

    1998-01-01

    The folding pathway of apomyoglobin has been experimentally shown to have early kinetic intermediates involving the A, B, G, and H helices. The earliest detected kinetic events occur on a ns to micros time scale. We show that the early folding kinetics of apomyoglobin may be understood as the association of nascent helices through a network of diffusion-collision-coalescence steps G + H <--> GH + A <--> AGH + B <--> ABGH obtained by solving the diffusion-collision model in a chemical kinetics approximation. Our reproduction of the experimental results indicates that the model is a useful way to analyze folding data. One prediction from our fit is that the nascent A and H helices should be relatively more helix-like before coalescence than the other apomyoglobin helices. PMID:9521125

  19. Kinetics and Mechanism--A Games Approach.

    ERIC Educational Resources Information Center

    Harsch, Gunther

    1984-01-01

    Proposes an approach to chemical kinetics and mechanism using statistical games, illustrating its use in monomolecular, catalytic, autocatalytic, consecutive, and equilibrium reactions. Major features of the games are also outlined and discussed. (JN)

  20. Polycondensation kinetics of furfuryl alcohol solutions

    NASA Astrophysics Data System (ADS)

    Zherebtsov, D. A.; Galimov, D. M.; Zagorul'ko, O. V.; Frolova, E. V.; Bol'shakov, O. I.; Zakharov, V. G.; Mikhailov, G. G.

    2016-01-01

    Changes in the viscosity, electrical conductivity, monomer concentration, and the size of growing molecules of polycondensed furfuryl alcohol are studied in solutions containing triethylene glycol and isooctylphenyldecaethylene glycol. The effect the solution compositions have on the condensation kinetics is considered.

  1. Diffusion influence on Michaelis-Menten kinetics

    NASA Astrophysics Data System (ADS)

    Kim, Hyojoon; Yang, Mino; Choi, Myung-Un; Shin, Kook Joe

    2001-07-01

    Influence of diffusion on the Michaelis-Menten kinetics is investigated with the renormalized kinetic theory recently proposed by Yang et al. [J. Chem. Phys. 108, 117; 108, 8557; 108, 9069 (1998)]. The nonlinearity predicted previously by Zhou [J. Phys. Chem. 101, 6642 (1997)] in the Lineweaver-Burk plot for the high concentration of substrate with his empirical expression and simulation is correctly obtained by the kinetic theory. We discuss possible errors in the estimation of reaction parameters caused by ignoring this nonlinearity in an experimental analysis (performed at even lower concentrations of the substrate). The time evolution of the production rate shows a peak before it reaches the steady-state value. The long time asymptotic relaxation of the deviation of the enzyme concentration from the steady-state value shows t-1/2 power-law behavior instead of the exponential decay predicted by the classical kinetics.

  2. Algebraic operator approach to gas kinetic models

    NASA Astrophysics Data System (ADS)

    Il'ichov, L. V.

    1997-02-01

    Some general properties of the linear Boltzmann kinetic equation are used to present it in the form ∂ tϕ = - †Âϕ with the operators Âand† possessing some nontrivial algebraic properties. When applied to the Keilson-Storer kinetic model, this method gives an example of quantum ( q-deformed) Lie algebra. This approach provides also a natural generalization of the “kangaroo model”.

  3. Finite-dimensional collisionless kinetic theory

    NASA Astrophysics Data System (ADS)

    Burby, J. W.

    2017-03-01

    A collisionless kinetic plasma model may often be cast as an infinite-dimensional noncanonical Hamiltonian system. I show that, when this is the case, the model can be discretized in space and particles while preserving its Hamiltonian structure, thereby producing a finite-dimensional Hamiltonian system that approximates the original kinetic model. I apply the general theory to two example systems: the relativistic Vlasov-Maxwell system with spin and a gyrokinetic Vlasov-Maxwell system.

  4. Joint Non-kinetic Effects Model (JNEM)

    NASA Technical Reports Server (NTRS)

    Chamberlain, Robert G.; Metivier, Timothy

    2006-01-01

    This slide presentation reviews the development of the Joint Non-kinetic Effects Model (JNEM), which is tool to support Battle Command Training that links simulation-generated non-kinetic events and outcomes to Training Audience Command and Staff decisions. JNEM helps create the operating environment for the following population groups (P-groups): (1) Local Civilians on the Battlefield, (2) Inter-Governmental Organizations (3) Non-Governmental Organizations (4) Contractors on the battlefield.

  5. NLTE4 Plasma Population Kinetics Database

    National Institute of Standards and Technology Data Gateway

    SRD 159 NLTE4 Plasma Population Kinetics Database (Web database for purchase)   This database contains benchmark results for simulation of plasma population kinetics and emission spectra. The data were contributed by the participants of the 4th Non-LTE Code Comparison Workshop who have unrestricted access to the database. The only limitation for other users is in hidden labeling of the output results. Guest users can proceed to the database entry page without entering userid and password.

  6. Ozone mass transfer and kinetics experiments

    SciTech Connect

    Bollyky, L.J.; Beary, M.M.

    1981-12-01

    Experiments were conducted at the Hanford Site to determine the most efficient pH and temperature levels for the destruction of complexants in Hanford high-level defense waste. These complexants enhance migration of radionuclides in the soil and inhibit the growth of crystals in the evaporator-crystallizer. Ozone mass transfer and kinetics tests have been outlined for the determination of critical mass transfer and kinetics parameters of the ozone-complexant reaction.

  7. Kinetic partitioning mechanism of HDV ribozyme folding.

    PubMed

    Chen, Jiawen; Gong, Sha; Wang, Yujie; Zhang, Wenbing

    2014-01-14

    RNA folding kinetics is directly tied to RNA biological functions. We introduce here a new approach for predicting the folding kinetics of RNA secondary structure with pseudoknots. This approach is based on our previous established helix-based method for predicting the folding kinetics of RNA secondary structure. In this approach, the transition rates for an elementary step: (1) formation, (2) disruption of a helix stem, and (3) helix formation with concomitant partial melting of an incompatible helix, are calculated with the free energy landscape. The folding kinetics of the Hepatitis delta virus (HDV) ribozyme and the mutated sequences are studied with this method. The folding pathways are identified by recursive searching the states with high net flux-in(out) population starting from the native state. The theory results are in good agreement with that of the experiments. The results indicate that the bi-phasic folding kinetics for the wt HDV sequence is ascribed to the kinetic partitioning mechanism: Part of the population will quickly fold to the native state along the fast pathway, while another part of the population will fold along the slow pathway, in which the population is trapped in a non-native state. Single mutation not only changes the folding rate but also the folding pathway.

  8. Dual kinetic curves in reversible electrochemical systems

    PubMed Central

    Hankins, Michael J.; Yablonsky, Gregory S.

    2017-01-01

    We introduce dual kinetic chronoamperometry, in which reciprocal relations are established between the kinetic curves of electrochemical reactions that start from symmetrical initial conditions. We have performed numerical and experimental studies in which the kinetic curves of the electron-transfer processes are analyzed for a reversible first order reaction. Experimental tests were done with the ferrocyanide/ferricyanide system in which the concentrations of each component could be measured separately using the platinum disk/gold ring electrode. It is shown that the proper ratio of the transient kinetic curves obtained from cathodic and anodic mass transfer limited regions give thermodynamic time invariances related to the reaction quotient of the bulk concentrations. Therefore, thermodynamic time invariances can be observed at any time using the dual kinetic curves for reversible reactions. The technique provides a unique possibility to extract the non-steady state trajectory starting from one initial condition based only on the equilibrium constant and the trajectory which starts from the symmetrical initial condition. The results could impact battery technology by predicting the concentrations and currents of the underlying non-steady state processes in a wide domain from thermodynamic principles and limited kinetic information. PMID:28358881

  9. Kinetic partitioning mechanism of HDV ribozyme folding

    SciTech Connect

    Chen, Jiawen; Gong, Sha; Wang, Yujie; Zhang, Wenbing

    2014-01-14

    RNA folding kinetics is directly tied to RNA biological functions. We introduce here a new approach for predicting the folding kinetics of RNA secondary structure with pseudoknots. This approach is based on our previous established helix-based method for predicting the folding kinetics of RNA secondary structure. In this approach, the transition rates for an elementary step: (1) formation, (2) disruption of a helix stem, and (3) helix formation with concomitant partial melting of an incompatible helix, are calculated with the free energy landscape. The folding kinetics of the Hepatitis delta virus (HDV) ribozyme and the mutated sequences are studied with this method. The folding pathways are identified by recursive searching the states with high net flux-in(out) population starting from the native state. The theory results are in good agreement with that of the experiments. The results indicate that the bi-phasic folding kinetics for the wt HDV sequence is ascribed to the kinetic partitioning mechanism: Part of the population will quickly fold to the native state along the fast pathway, while another part of the population will fold along the slow pathway, in which the population is trapped in a non-native state. Single mutation not only changes the folding rate but also the folding pathway.

  10. Kinetic partitioning mechanism of HDV ribozyme folding

    NASA Astrophysics Data System (ADS)

    Chen, Jiawen; Gong, Sha; Wang, Yujie; Zhang, Wenbing

    2014-01-01

    RNA folding kinetics is directly tied to RNA biological functions. We introduce here a new approach for predicting the folding kinetics of RNA secondary structure with pseudoknots. This approach is based on our previous established helix-based method for predicting the folding kinetics of RNA secondary structure. In this approach, the transition rates for an elementary step: (1) formation, (2) disruption of a helix stem, and (3) helix formation with concomitant partial melting of an incompatible helix, are calculated with the free energy landscape. The folding kinetics of the Hepatitis delta virus (HDV) ribozyme and the mutated sequences are studied with this method. The folding pathways are identified by recursive searching the states with high net flux-in(out) population starting from the native state. The theory results are in good agreement with that of the experiments. The results indicate that the bi-phasic folding kinetics for the wt HDV sequence is ascribed to the kinetic partitioning mechanism: Part of the population will quickly fold to the native state along the fast pathway, while another part of the population will fold along the slow pathway, in which the population is trapped in a non-native state. Single mutation not only changes the folding rate but also the folding pathway.

  11. Kinetic Description of the Impedance Probe

    NASA Astrophysics Data System (ADS)

    Oberrath, Jens; Lapke, Martin; Mussenbrock, Thomas; Brinkmann, Ralf

    2011-10-01

    Active plasma resonance spectroscopy is a well known diagnostic method. Many concepts of this method are theoretically investigated and realized as a diagnostic tool, one of which is the impedance probe (IP). The application of such a probe in plasmas with pressures of a few Pa raises the question whether kinetic effects have to be taken into account or not. To address this question a kinetic model is necessary. A general kinetic model for an electrostatic concept of active plasma spectroscopy was presented by R.P. Brinkmann and can be used to describe the multipole resonance probe (MRP). In principle the IP is interpretable as a special case of the MRP in lower order. Thus, we are able to describe the IP by the kinetic model of the MRP. Based on this model we derive a solution to investigate the influence of kinetic effects to the resonance behavior of the IP. Active plasma resonance spectroscopy is a well known diagnostic method. Many concepts of this method are theoretically investigated and realized as a diagnostic tool, one of which is the impedance probe (IP). The application of such a probe in plasmas with pressures of a few Pa raises the question whether kinetic effects have to be taken into account or not. To address this question a kinetic model is necessary. A general kinetic model for an electrostatic concept of active plasma spectroscopy was presented by R.P. Brinkmann and can be used to describe the multipole resonance probe (MRP). In principle the IP is interpretable as a special case of the MRP in lower order. Thus, we are able to describe the IP by the kinetic model of the MRP. Based on this model we derive a solution to investigate the influence of kinetic effects to the resonance behavior of the IP. The authors acknowledge the support by the Deutsche Forschungsgemeinschaft (DFG) via the Ruhr University Research School and the Federal Ministry of Education and Research in frame of the PluTO project.

  12. The Role of Target Binding Kinetics in Drug Discovery.

    PubMed

    Guo, Dong; Heitman, Laura H; IJzerman, Adriaan P

    2015-11-01

    Traditionally structure-activity/affinity relationships (SAR) have dominated research in medicinal chemistry. However, structure-kinetics relationships (SKR) can be very informative too. In this viewpoint we explore the molecular determinants of binding kinetics and discuss challenges for future binding kinetics studies. A scheme for future kinetics-directed drug design and discovery is also proposed.

  13. Kinetics of PBX9404 Aging

    SciTech Connect

    Burnham, A K; Fried, L E

    2006-09-11

    blue color decades after formulation. Subsequently, heat and light both send it through a progression of colors from grayish blue, blue-green, green, brown, dirty yellow, mottled tan, and eventually pale tan. The progression is accelerated by oxygen and possibly moisture, as has been shown in several accelerated aging studies. The precise compounds causing the color evolution are uncertain, but they are undoubtedly a progression of quinoidal, nitroso, and nitrated DPA compounds. For example, paranitroso DPA is deep blue. Unfortunately, the location of various nitrated DPAs, which ranged from yellow to orange to red to brown and which were used by Pantex as analytical standards in the 1970s, is not currently known. While the color change is indicative of aging, it is by no means a quantitative measure of the extent of nitrocellulose degradation. Inspection of the literature yielded a variety of kinetic models, and the activation energy typically ranges from 25-35 kcal/mol for T<100 C. This literature qualitatively predicts times for 30% decomposition ranging from a few days at 100 C to 1-2 years at 50 C to 50 years at room temperature. To develop a quantitative model, we used the data of Leider and Seaton, which were collected at conditions most closely matching stockpile conditions for any data set we had available. They used PBX 9404 heated as pressed pellets in closed vessels at temperatures ranging from 50 to 100 C for times up to three years, and they report mass loss, gas yield and composition, and chemical analysis of the residual solid by methods used in stockpile surveillance. Initial kinetic analysis of the weight of remaining nitrocellulose as measured by liquid chromatography and the loss of nitrate esters by a colorimetric technique gave an activation energy of 27 kcal/mol. However, the reaction is complex due to the different stability of the three nitroester positions, and this complexity required either parallel first-order reactions or an nth

  14. Resonance Van Hove singularities in wave kinetics

    NASA Astrophysics Data System (ADS)

    Shi, Yi-Kang; Eyink, Gregory L.

    2016-10-01

    Wave kinetic theory has been developed to describe the statistical dynamics of weakly nonlinear, dispersive waves. However, we show that systems which are generally dispersive can have resonant sets of wave modes with identical group velocities, leading to a local breakdown of dispersivity. This shows up as a geometric singularity of the resonant manifold and possibly as an infinite phase measure in the collision integral. Such singularities occur widely for classical wave systems, including acoustical waves, Rossby waves, helical waves in rotating fluids, light waves in nonlinear optics and also in quantum transport, e.g. kinetics of electron-hole excitations (matter waves) in graphene. These singularities are the exact analogue of the critical points found by Van Hove in 1953 for phonon dispersion relations in crystals. The importance of these singularities in wave kinetics depends on the dimension of phase space D =(N - 2) d (d physical space dimension, N the number of waves in resonance) and the degree of degeneracy δ of the critical points. Following Van Hove, we show that non-degenerate singularities lead to finite phase measures for D > 2 but produce divergences when D ≤ 2 and possible breakdown of wave kinetics if the collision integral itself becomes too large (or even infinite). Similar divergences and possible breakdown can occur for degenerate singularities, when D - δ ≤ 2, as we find for several physical examples, including electron-hole kinetics in graphene. When the standard kinetic equation breaks down, then one must develop a new singular wave kinetics. We discuss approaches from pioneering 1971 work of Newell & Aucoin on multi-scale perturbation theory for acoustic waves and field-theoretic methods based on exact Schwinger-Dyson integral equations for the wave dynamics.

  15. Simplification of the unified gas kinetic scheme

    NASA Astrophysics Data System (ADS)

    Chen, Songze; Guo, Zhaoli; Xu, Kun

    2016-08-01

    The unified gas kinetic scheme (UGKS) is an asymptotic preserving (AP) scheme for kinetic equations. It is superior for transition flow simulation and has been validated in the past years. However, compared to the well-known discrete ordinate method (DOM), which is a classical numerical method solving the kinetic equations, the UGKS needs more computational resources. In this study, we propose a simplification of the unified gas kinetic scheme. It allows almost identical numerical cost as the DOM, but predicts numerical results as accurate as the UGKS. In the simplified scheme, the numerical flux for the velocity distribution function and the numerical flux for the macroscopic conservative quantities are evaluated separately. The equilibrium part of the UGKS flux is calculated by analytical solution instead of the numerical quadrature in velocity space. The simplification is equivalent to a flux hybridization of the gas kinetic scheme for the Navier-Stokes (NS) equations and the conventional discrete ordinate method. Several simplification strategies are tested, through which we can identify the key ingredient of the Navier-Stokes asymptotic preserving property. Numerical tests show that, as long as the collision effect is built into the macroscopic numerical flux, the numerical scheme is Navier-Stokes asymptotic preserving, regardless the accuracy of the microscopic numerical flux for the velocity distribution function.

  16. Chemical Kinetic Modeling of Advanced Transportation Fuels

    SciTech Connect

    PItz, W J; Westbrook, C K; Herbinet, O

    2009-01-20

    Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

  17. Kinetic parameters for source driven systems

    SciTech Connect

    Dulla, S.; Ravetto, P.; Carta, M.; D'Angelo, A.

    2006-07-01

    The definition of the characteristic kinetic parameters of a subcritical source-driven system constitutes an interesting problem in reactor physics with important consequences for practical applications. Consistent and physically meaningful values of the parameters allow to obtain accurate results from kinetic simulation tools and to correctly interpret kinetic experiments. For subcritical systems a preliminary problem arises for the adoption of a suitable weighting function to be used in the projection procedure to derive a point model. The present work illustrates a consistent factorization-projection procedure which leads to the definition of the kinetic parameters in a straightforward manner. The reactivity term is introduced coherently with the generalized perturbation theory applied to the source multiplication factor ks, which is thus given a physical role in the kinetic model. The effective prompt lifetime is introduced on the assumption that a neutron generation can be initiated by both the fission process and the source emission. Results are presented for simplified configurations to fully comprehend the physical features and for a more complicated highly decoupled system treated in transport theory. (authors)

  18. Viral kinetic modeling: state of the art

    SciTech Connect

    Canini, Laetitia; Perelson, Alan S.

    2014-06-25

    Viral kinetic modeling has led to increased understanding of the within host dynamics of viral infections and the effects of therapy. Here we review recent developments in the modeling of viral infection kinetics with emphasis on two infectious diseases: hepatitis C and influenza. We review how viral kinetic modeling has evolved from simple models of viral infections treated with a drug or drug cocktail with an assumed constant effectiveness to models that incorporate drug pharmacokinetics and pharmacodynamics, as well as phenomenological models that simply assume drugs have time varying-effectiveness. We also discuss multiscale models that include intracellular events in viral replication, models of drug-resistance, models that include innate and adaptive immune responses and models that incorporate cell-to-cell spread of infection. Overall, viral kinetic modeling has provided new insights into the understanding of the disease progression and the modes of action of several drugs. In conclusion, we expect that viral kinetic modeling will be increasingly used in the coming years to optimize drug regimens in order to improve therapeutic outcomes and treatment tolerability for infectious diseases.

  19. Viral kinetic modeling: state of the art

    DOE PAGES

    Canini, Laetitia; Perelson, Alan S.

    2014-06-25

    Viral kinetic modeling has led to increased understanding of the within host dynamics of viral infections and the effects of therapy. Here we review recent developments in the modeling of viral infection kinetics with emphasis on two infectious diseases: hepatitis C and influenza. We review how viral kinetic modeling has evolved from simple models of viral infections treated with a drug or drug cocktail with an assumed constant effectiveness to models that incorporate drug pharmacokinetics and pharmacodynamics, as well as phenomenological models that simply assume drugs have time varying-effectiveness. We also discuss multiscale models that include intracellular events in viralmore » replication, models of drug-resistance, models that include innate and adaptive immune responses and models that incorporate cell-to-cell spread of infection. Overall, viral kinetic modeling has provided new insights into the understanding of the disease progression and the modes of action of several drugs. In conclusion, we expect that viral kinetic modeling will be increasingly used in the coming years to optimize drug regimens in order to improve therapeutic outcomes and treatment tolerability for infectious diseases.« less

  20. Kinetic energy budgets in areas of convection

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.

    1979-01-01

    Synoptic scale budgets of kinetic energy are computed using 3 and 6 h data from three of NASA's Atmospheric Variability Experiments (AVE's). Numerous areas of intense convection occurred during the three experiments. Large kinetic energy variability, with periods as short as 6 h, is observed in budgets computed over each entire experiment area and over limited volumes that barely enclose the convection and move with it. Kinetic energy generation and transport processes in the smaller volumes are often a maximum when the enclosed storms are near peak intensity, but the nature of the various energy processes differs between storm cases and seems closely related to the synoptic conditions. A commonly observed energy budget for peak storm intensity indicates that generation of kinetic energy by cross-contour flow is the major energy source while dissipation to subgrid scales is the major sink. Synoptic scale vertical motion transports kinetic energy from lower to upper levels of the atmosphere while low-level horizontal flux convergence and upper-level horizontal divergence also occur. Spatial fields of the energy budget terms show that the storm environment is a major center of energy activity for the entire area.

  1. Kinetics of microbial growth on pentachlorophenol.

    PubMed Central

    Klecka, G M; Maier, W J

    1985-01-01

    Batch and fed-batch experiments were conducted to examine the kinetics of pentachlorophenol utilization by an enrichment culture of pentachlorophenol-degrading bacteria. The Haldane modification of the Monod equation was found to describe the relationship between the specific growth rate and substrate concentration. Analysis of the kinetic parameters indicated that the maximum specific growth rate and yield coefficients are low, with values of 0.074 h-1 and 0.136 g/g, respectively. The Monod constant (Ks) was estimated to be 60 micrograms/liter, indicating a high affinity of the microorganisms for the substrate. However, high concentrations (KI = 1,375 micrograms/liter) were shown to be inhibitory for metabolism and growth. These kinetic parameters can be used to define the optimal conditions for the removal of pentachlorophenol in biological treatment systems. PMID:3977315

  2. Kinetic-energy-momentum tensor in electrodynamics

    NASA Astrophysics Data System (ADS)

    Sheppard, Cheyenne J.; Kemp, Brandon A.

    2016-01-01

    We show that the Einstein-Laub formulation of electrodynamics is invalid since it yields a stress-energy-momentum (SEM) tensor that is not frame invariant. Two leading hypotheses for the kinetic formulation of electrodynamics (Chu and Einstein-Laub) are studied by use of the relativistic principle of virtual power, mathematical modeling, Lagrangian methods, and SEM transformations. The relativistic principle of virtual power is used to demonstrate the field dynamics associated with energy relations within a relativistic framework. Lorentz transformations of the respective SEM tensors demonstrate the relativistic frameworks for each studied formulation. Mathematical modeling of stationary and moving media is used to illustrate the differences and discrepancies of specific proposed kinetic formulations, where energy relations and conservation theorems are employed. Lagrangian methods are utilized to derive the field kinetic Maxwell's equations, which are studied with respect to SEM tensor transforms. Within each analysis, the Einstein-Laub formulation violates special relativity, which invalidates the Einstein-Laub SEM tensor.

  3. Determination of kinetic parameters for biomass combustion.

    PubMed

    Álvarez, A; Pizarro, C; García, R; Bueno, J L; Lavín, A G

    2016-09-01

    The aim of this work is to provide a wide database of kinetic data for the most common biomass by thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). Due to the characteristic parameters of DTG curves, a two-stage reaction model is proposed and the kinetic parameters obtained from model-based methods with energy activation values for first and second stages in the range 1.75·10(4)-1.55·10(5)J/mol and 1.62·10(4)-2.37·10(5)J/mol, respectively. However, it has been found that Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose model-free methods are not suitable to determine the kinetic parameters of biomass combustion since the assumptions of these two methods were not accomplished in the full range of the combustion process.

  4. Kinetic theory of virus capsid assembly.

    PubMed

    van der Schoot, Paul; Zandi, Roya

    2007-11-26

    A phenomenological theory is presented for the kinetics of the in vitro assembly and disassembly of icosahedral virus capsids in solutions of coat proteins. The focus is on conditions where nucleation-type processes can be ignored. We find that the kinetics of assembly is strongly concentration dependent and that the late-stage relaxation time varies as the inverse of the square of the concentration. These findings are corroborated by experimental observations on a number of viruses. Further, our theory shows that hysteresis observed in some experiments could be a direct effect of the kinetics of a high-order mass action law, not necessarily the result of a free energy barrier between assembled and disassembled states.

  5. Kinetics of pack aluminization of nickel

    NASA Technical Reports Server (NTRS)

    Seigle, L. L.; Gupta, B. K.; Shankar, R.; Sarkhel, A. K.

    1978-01-01

    The kinetics of pack aluminization of unalloyed nickel in packs of varying aluminum activity with various halide activators were studied. Surface compositions of the coatings as functions of time, temperature, and pack composition were obtained in order to establish the boundary conditions for diffusion in the system. The structure of the packs was also examined in order to clarify the mechanism of aluminum transport. The results indicate that the kinetics of pack aluminization are controlled jointly by gas diffusion in the pack and solid diffusion in the coating. Levine and Caves' model for gas diffusion was combined with calculations of rates of diffusion in the solid to formulate a more complete theory for the kinetics of pack aluminization.

  6. Nanopore DNA sequencing using kinetic proofreading

    NASA Astrophysics Data System (ADS)

    Ling, Xinsheng

    We propose a method of DNA sequencing by combining the physical method of nanopore electrical measurements and Southern's sequencing-by-hybridization. The new key ingredient, essential to both lowering the costs and increasing the precision, is an asymmetric nanopore sandwich device capable of measuring the DNA hybridization probe twice separated by a designed waiting time. Those incorrect probes appearing only once in nanopore ionic current traces are discriminated from the correct ones that appear twice. This method of discrimination is similar to the principle of kinetic proofreading proposed by Hopfield and Ninio in gene transcription and translation processes. An error analysis is of this nanopore kinetic proofreading (nKP) technique for DNA sequencing is carried out in comparison with the most precise 3' dideoxy termination method developed by Sanger. Nanopore DNA sequencing using kinetic proofreading.

  7. Nonlocal kinetic-energy-density functionals

    SciTech Connect

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E. |

    1996-04-01

    In this paper we present nonlocal kinetic-energy functionals {ital T}[{ital n}] within the average density approximation (ADA) framework, which do not require any extra input when applied to any electron system and recover the exact kinetic energy and the linear response function of a homogeneous system. In contrast with previous ADA functionals, these present good behavior of the long-range tail of the exact weight function. The averaging procedure for the kinetic functional (averaging the Fermi momentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculation of extended systems, and it gives excellent results when applied to atoms and jellium surfaces. {copyright} {ital 1996 The American Physical Society.}

  8. Filamentary and hierarchical pictures - Kinetic energy criterion

    NASA Technical Reports Server (NTRS)

    Klypin, Anatoly A.; Melott, Adrian L.

    1992-01-01

    We present a new criterion for formation of second-generation filaments. The criterion called the kinetic energy ratio, KR, is based on comparison of peculiar velocities at different scales. We suggest that the clumpiness of the distribution in some cases might be less important than the 'coldness' or 'hotness' of the flow for formation of coherent structures. The kinetic energy ratio is analogous to the Mach number except for one essential difference. If at some scale KR is greater than 1, as estimated at the linear stage, then when fluctuations of this scale reach nonlinearity, the objects they produce must be anisotropic ('filamentary'). In the case of power-law initial spectra the kinetic ratio criterion suggests that the border line is the power-spectrum with the slope n = -1.

  9. Kinetics and thermodynamics of living copolymerization processes

    NASA Astrophysics Data System (ADS)

    Gaspard, Pierre

    2016-11-01

    Theoretical advances are reported on the kinetics and thermodynamics of free and template-directed living copolymerizations. Until recently, the kinetic theory of these processes had only been established in the fully irreversible regime, in which the attachment rates are only considered. However, the entropy production is infinite in this regime and the approach to thermodynamic equilibrium cannot be investigated. For this purpose, the detachment rates should also be included. Inspite of this complication, the kinetics can be exactly solved in the regimes of steady growth and depolymerization. In this way, analytical expressions are obtained for the mean growth velocity, the statistical properties of the copolymer sequences, as well as the thermodynamic entropy production. The results apply to DNA replication, transcription and translation, allowing us to understand important aspects of molecular evolution. This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.

  10. Variability in human in vitro enzyme kinetics.

    PubMed

    Wang, Ying-Hong; Gibson, Christopher R

    2014-01-01

    There are many factors which are known to cause variability in human in vitro enzyme kinetic data. Factors such as the source of enzyme and how it was prepared, the genetics and background of the donor, how the in vitro studies are designed, and how the data are analyzed contribute to variability in the resulting kinetic parameters. It is important to consider not only the factors which cause variability within an experiment, such as selection of a probe substrate, but also those that cause variability when comparing kinetic data across studies and laboratories. For example, the artificial nature of the microsomal lipid membrane and microenvironment in some recombinantly expressed enzymes, relative to those found in native tissue microsomes, has been shown to influence enzyme activity and thus can be a source of variability when comparing across the two different systems. All of these factors, and several others, are discussed in detail in the chapter below.

  11. Isoconversional Kinetics of Polymers: The Decade Past.

    PubMed

    Vyazovkin, Sergey

    2017-02-01

    This article surveys the decade of progress accomplished in the application of isoconversional methods to thermally stimulated processes in polymers. The processes of interest include: crystallization and melting of polymers, gelation of polymer solutions and gel melting, denaturation (unfolding) of proteins, glass transition, polymerization and crosslinking (curing), and thermal and thermo-oxidative degradation. Special attention is paid to the kinetics of polymeric nanomaterials. The article discusses basic principles for understanding the variations in the activation energy and emphasizes the possibility of using models for linking such variations to the parameters of individual kinetic steps. It is stressed that many kinetic effects are not linked to a change in the activation energy alone and may arise from changes in the preexponential factor and reaction model. Also noted is that some isoconversional methods are inapplicable to processes taking place on cooling and cannot be used to study such processes as the melt crystallization.

  12. Kinetic Approaches to Measuring Peroxiredoxin Reactivity

    PubMed Central

    Winterbourn, Christine C.; Peskin, Alexander V.

    2016-01-01

    Peroxiredoxins are ubiquitous thiol proteins that catalyse the breakdown of peroxides and regulate redox activity in the cell. Kinetic analysis of their reactions is required in order to identify substrate preferences, to understand how molecular structure affects activity and to establish their physiological functions. Various approaches can be taken, including the measurement of rates of individual steps in the reaction pathway by stopped flow or competitive kinetics, classical enzymatic analysis and measurement of peroxidase activity. Each methodology has its strengths and they can often give complementary information. However, it is important to understand the experimental conditions of the assay so as to interpret correctly what parameter is being measured. This brief review discusses different kinetic approaches and the information that can be obtained from them. PMID:26813658

  13. Turbulence kinetic energy equation for dilute suspensions

    NASA Technical Reports Server (NTRS)

    Abou-Arab, T. W.; Roco, M. C.

    1989-01-01

    A multiphase turbulence closure model is presented which employs one transport equation, namely the turbulence kinetic energy equation. The proposed form of this equation is different from the earlier formulations in some aspects. The power spectrum of the carrier fluid is divided into two regions, which interact in different ways and at different rates with the suspended particles as a function of the particle-eddy size ratio and density ratio. The length scale is described algebraically. A mass/time averaging procedure for the momentum and kinetic energy equations is adopted. The resulting turbulence correlations are modeled under less retrictive assumptions comparative to previous work. The closures for the momentum and kinetic energy equations are given. Comparisons of the predictions with experimental results on liquid-solid jet and gas-solid pipe flow show satisfactory agreement.

  14. A kinetic cross-field streaming instability

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Winske, D.; Papadopoulos, K.; Zhou, Y. M.; Tsai, S. T.; Guo, S. C.

    1983-01-01

    In a high-beta plasma the so-called modified-two-stream instability, which results from strongly magnetized electrons drifting relative to unmagnetized ions across a homogeneous magnetic field, is misnamed because the mode is highly kinetic, particularly when the relative streaming velocity exceeds the Alfven speed of the plasma. This kinetic cross-field streaming instability is investigated in detail, examining the effect of the electromagnetic terms and the stability boundaries in both low- and high-beta plasmas. An approximate dispersion relation showing the relation of this mode to the whistler is derived and solutions of it are compared with those obtained from the exact dispersion relation. The kinetic mode, unlike the usual modified-two-stream instability, is not stabilized by electromagnetic effects when the relative electron-ion drift speed exceeds the Alfven speed.

  15. Kinetic chain abnormalities in the athletic shoulder.

    PubMed

    Sciascia, Aaron; Thigpen, Charles; Namdari, Surena; Baldwin, Keith

    2012-03-01

    Overhead activities require the shoulder to be exposed to and sustain repetitive loads. The segmental activation of the body's links, known as the kinetic chain, allows this to occur effectively. Proper muscle activation is achieved through generation of energy from the central segment or core, which then transfers the energy to the terminal links of the shoulder, elbow, and hand. The kinetic chain is best characterized by 3 components: optimized anatomy, reproducible efficient motor patterns, and the sequential generation of forces. However, tissue injury and anatomic deficits such as weakness and/or tightness in the leg, pelvic core, or scapular musculature can lead to overuse shoulder injuries. These injuries can be prevented and maladaptations can be detected with a thorough understanding of biomechanics of the kinetic chain as it relates to overhead activity.

  16. Determining anaerobic degradation kinetics from batch tests.

    PubMed

    Moreda, Iván López

    2016-01-01

    Data obtained from a biomethane potential (BMP) test were used in order to obtain the parameters of a kinetic model of solid wastes anaerobic degradation. The proposed model considers a hydrolysis step with a first order kinetic, a Monod kinetic for the soluble organic substrate degradation and a first order decay of microorganisms. The instantaneous release of methane was assumed. The parameters of the model are determined following a direct search optimization procedure. A 'multiple-shooting' technique was used as a first step of the optimization process. The confidence interval of the parameters was determined by using Monte Carlo simulations. Also, the distribution functions of the parameters were determined. Only the hydrolysis first order constant shows a normal distribution.

  17. The hydrothermal reaction kinetics of aspartic acid

    NASA Astrophysics Data System (ADS)

    Cox, Jenny S.; Seward, Terry M.

    2007-02-01

    Experimental data on the hydrothermal reaction kinetics of aspartic acid were acquired using a custom-built spectrophotometric reaction cell which permits in situ observation under hydrothermal conditions. The results of this study indicate that the reaction kinetics of dilute aspartic acid solutions are significantly different depending on the presence or absence of catalytic surfaces such as standard metal alloys. The spectroscopic data presented here represent the first direct observations, in situ and in real time, of an amino acid reacting in a hydrothermal solution. Quantitative kinetic information, including rate constants, concentration versus time profiles, and calculations of the individual component spectra, was obtained from the data using a chemometric approach based on factor analysis/principle component analysis which treats the rate expressions simultaneously as a system of differential algebraic equations (DAE) of index 1. Identification of the products was confirmed where possible by high pressure anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The reaction kinetics of aspartic acid under hydrothermal conditions was observed to be highly complex, in contrast to previous studies which indicated almost exclusively deamination. At lower temperatures (120-170 °C), several different reaction pathways were observed, including decarboxylation and polymerization, and the catalytic effects of reactor surfaces on the aspartic acid system were clearly demonstrated. At higher temperatures (above 170 °C), aspartic acid exhibited highly complex behaviour, with evidence indicating that it can simultaneously dimerize and cyclize, deaminate (by up to two pathways), and decarboxylate (by up to two pathways). These higher temperature kinetics were not fully resolvable in a quantitative manner due to the complexity of the system and the constraints of UV spectroscopy. The results of this study provide strong evidence that the reaction

  18. Kinetic studies of elementary chemical reactions

    SciTech Connect

    Durant, J.L. Jr.

    1993-12-01

    This program concerning kinetic studies of elementary chemical reactions is presently focussed on understanding reactions of NH{sub x} species. To reach this goal, the author is pursuing experimental studies of reaction rate coefficients and product branching fractions as well as using electronic structure calculations to calculate transition state properties and reaction rate calculations to relate these properties to predicted kinetic behavior. The synergy existing between the experimental and theoretical studies allow one to gain a deeper insight into more complex elementary reactions.

  19. Regulation of neurotransmitter release kinetics by NSF.

    PubMed

    Schweizer, F E; Dresbach, T; DeBello, W M; O'Connor, V; Augustine, G J; Betz, H

    1998-02-20

    NSF (N-ethylmaleimide-sensitive factor) is an adenosine triphosphatase (ATPase) that contributes to a protein complex essential for membrane fusion. The synaptic function of this protein was investigated by injecting, into the giant presynaptic terminal of squid, peptides that inhibit the ATPase activity of NSF stimulated by the soluble NSF attachment protein (SNAP). These peptides reduced the amount and slowed the kinetics of neurotransmitter release as a result of actions that required vesicle turnover and occurred at a step subsequent to vesicle docking. These results define NSF as an essential participant in synaptic vesicle exocytosis that regulates the kinetics of neurotransmitter release and, thereby, the integrative properties of synapses.

  20. Kinetics of luminol sonochemiluminescence quenched by purines.

    PubMed

    Wang, Jian; Lai, Yongquan; Chen, Meili; Jiang, Zhou; Chen, Guonan

    2013-01-01

    A homogeneous chemiluminescence (CL) reaction was initiated by ultrasound irradiation. Luminol sonochemiluminescence (SCL) reaction kinetics were determined under pseudo-first-order conditions, and the reaction followed the model for simple rise-fall kinetics. In addition, SCL quenching reactions induced by purines were also investigated in which the interactions between luminol and purines were analysed using the Stern-Volmer (S-V) mechanism. The results implied that the high rate constant of luminol CL quenched by purines may be attributed to ground state interactions originating from hydrogen bonding.

  1. Nonlinear response theory in chemical kinetics.

    PubMed

    Kryvohuz, Maksym; Mukamel, Shaul

    2014-01-21

    A theory of nonlinear response of chemical kinetics, in which multiple perturbations are used to probe the time evolution of nonlinear chemical systems, is developed. Expressions for nonlinear chemical response functions and susceptibilities, which can serve as multidimensional measures of the kinetic pathways and rates, are derived. A new class of multidimensional measures that combine multiple perturbations and measurements is also introduced. Nonlinear fluctuation-dissipation relations for steady-state chemical systems, which replace operations of concentration measurement and perturbations, are proposed. Several applications to the analysis of complex reaction mechanisms are provided.

  2. Neutral Vlasov kinetic theory of magnetized plasmas

    SciTech Connect

    Tronci, Cesare; Camporeale, Enrico

    2015-02-15

    The low-frequency limit of Maxwell equations is considered in the Maxwell-Vlasov system. This limit produces a neutral Vlasov system that captures essential features of plasma dynamics, while neglecting radiation effects. Euler-Poincaré reduction theory is used to show that the neutral Vlasov kinetic theory possesses a variational formulation in both Lagrangian and Eulerian coordinates. By construction, the new model recovers all collisionless neutral models employed in plasma simulations. Then, comparisons between the neutral Vlasov system and hybrid kinetic-fluid models are presented in the linear regime.

  3. Kinetic determination of selenium in biological material

    SciTech Connect

    Efremenko, O.A.; Krasnyuk, I.I.; Kudrin, A.N.; Rudenko, B.A.

    1986-05-10

    A very promising method for selenium determination is a kinetic analytical procedure that combines the simplicity and availability of physical instrumentation with a low analyte detection limit. This paper reports a modification of the method to enable the determination of selenium in rat blood and involves decomposing the sample with a mixture of nitric and perchloric acids, separation of the selenium (IV) from other decomposition products, and quantitatively determining selenium by the described kinetic method using the indicator reaction of iron (II) edetate oxidation by sodium nitrate.

  4. Kinetic Approach for Laser-Induced Plasmas

    SciTech Connect

    Omar, Banaz; Rethfeld, Baerbel

    2008-10-22

    Non-equilibrium distribution functions of electron gas and phonon gas excited with ultrashort intense laser pulses are calculated for laser-induced plasmas occurring in solids. The excitation during femtosecond irradiation and the subsequent thermalization of the free electrons, as well as the dynamics of phonons are described by kinetic equations. The microscopic collision processes, such as absorption by inverse bremsstrahlung, electron-electron collisions, and electron-phonon interactions are considered by complete Boltzmann collision integrals. We apply our kinetic approach for gold by taking s-band electron into account and compare it with the case of excitation of d-band electrons.

  5. Kinetic Structure of the Reconnection Diffusion Region

    NASA Astrophysics Data System (ADS)

    Khotyaintsev, Yuri

    2016-04-01

    We present high-resolution multi-spacecraft observations of electromagnetic fields and particle distributions by Magnetospheric Multiscale (MMS) mission throughout a reconnection layer at the sub-solar magnetopause. We study which terms in the generalized Ohm's law balance the observed electric field throughout the region. We also study waves and particle distribution functions in order to identify kinetic boundaries created due to acceleration and trapping of electrons and ions as well as mixing of electron populations from different sides of the reconnecting layer. We discuss the interplay between particles, waves, and DC electric and magnetic fields, which clearly demonstrates kinetic and multi-scale nature of the reconnection diffusion region.

  6. Kinetics of ligand binding to nucleic acids.

    PubMed

    Arakelyan, V B; Babayan, S Y; Tairyan, V I; Arakelyan, A V; Parsadanyan, M A; Vardevanyan, P O

    2006-02-01

    Ligand binding to nucleic acids (NA) is considered as a stationary Markov process. It is shown that the probabilistic description of ligand-NA binding allows one to describe not only the kinetics of the change of number of bound ligands at arbitrary fillings but also to calculate stationary values of the number of bound ligands and its dispersion. The general analysis of absorption isotherms and kinetics of ligand binding to NA make it possible to determine of rate constants of ligand-NA complex formation and dissociation.

  7. Determination of rate distributions from kinetic experiments.

    PubMed

    Steinbach, P J; Chu, K; Frauenfelder, H; Johnson, J B; Lamb, D C; Nienhaus, G U; Sauke, T B; Young, R D

    1992-01-01

    Rate processes in proteins are often not adequately described by simple exponential kinetics. Instead of modeling the kinetics in the time domain, it can be advantageous to perform a numerical inversion leading to a rate distribution function f(lambda). The features observed in f(lambda) (number, positions, and shapes of peaks) can then be interpreted. We discuss different numerical techniques for obtaining rate distribution functions, with special emphasis on the maximum entropy method. Examples are given for the application of these techniques to flash photolysis data of heme proteins.

  8. Kinetics of the fluorination of zinc

    NASA Technical Reports Server (NTRS)

    Odonnell, P. M.

    1975-01-01

    The reaction between zinc metal and fluorine gas can be described by a parabolic rate law. This reaction is both temperature and pressure dependent. Simple kinetics are complicated by the considerable vaporization rate for zinc at temperatures above 300 C (573 K).

  9. Chemical Dosing and First-Order Kinetics

    ERIC Educational Resources Information Center

    Hladky, Paul W.

    2011-01-01

    College students encounter a variety of first-order phenomena in their mathematics and science courses. Introductory chemistry textbooks that discuss first-order processes, usually in conjunction with chemical kinetics or radioactive decay, stop at single, discrete dose events. Although single-dose situations are important, multiple-dose events,…

  10. Stochastic thermodynamics for linear kinetic equations

    NASA Astrophysics Data System (ADS)

    Van den Broeck, C.; Toral, R.

    2015-07-01

    Stochastic thermodynamics is formulated for variables that are odd under time reversal. The invariance under spatial rotation of the collision rates due to the isotropy of the heat bath is shown to be a crucial ingredient. An alternative detailed fluctuation theorem is derived, expressed solely in terms of forward statistics. It is illustrated for a linear kinetic equation with kangaroo rates.

  11. An Inversion Recovery NMR Kinetics Experiment

    ERIC Educational Resources Information Center

    Williams, Travis J.; Kershaw, Allan D.; Li, Vincent; Wu, Xinping

    2011-01-01

    A convenient laboratory experiment is described in which NMR magnetization transfer by inversion recovery is used to measure the kinetics and thermochemistry of amide bond rotation. The experiment utilizes Varian spectrometers with the VNMRJ 2.3 software, but can be easily adapted to any NMR platform. The procedures and sample data sets in this…

  12. Solution Kinetics Database on the Web

    National Institute of Standards and Technology Data Gateway

    SRD 40 NDRL/NIST Solution Kinetics Database on the Web (Web, free access)   Data for free radical processes involving primary radicals from water, inorganic radicals and carbon-centered radicals in solution, and singlet oxygen and organic peroxyl radicals in various solvents.

  13. Chemical Kinetic and Aerodynamic Structures of Flames

    DTIC Science & Technology

    1992-06-11

    identification of the role of kinetics and system non- adiabaticity in flammability limits , and on adiabatic flame stabilization. These results are...stabilization and flammability, and supersonic combustion. .. SUIUECT TEUMS 15. NUMBE OF PAGESFlammability limit , flame extinction, hydrocarbon 55...flammability limits , and on adiabatic flame stabilization. These results are expected to be useful in the general interest of AFOSR in the fundamental and

  14. Kinetics methods for clinical epidemiology problems.

    PubMed

    Corlan, Alexandru Dan; Ross, John

    2015-11-17

    Calculating the probability of each possible outcome for a patient at any time in the future is currently possible only in the simplest cases: short-term prediction in acute diseases of otherwise healthy persons. This problem is to some extent analogous to predicting the concentrations of species in a reactor when knowing initial concentrations and after examining reaction rates at the individual molecule level. The existing theoretical framework behind predicting contagion and the immediate outcome of acute diseases in previously healthy individuals is largely analogous to deterministic kinetics of chemical systems consisting of one or a few reactions. We show that current statistical models commonly used in chronic disease epidemiology correspond to simple stochastic treatment of single reaction systems. The general problem corresponds to stochastic kinetics of complex reaction systems. We attempt to formulate epidemiologic problems related to chronic diseases in chemical kinetics terms. We review methods that may be adapted for use in epidemiology. We show that some reactions cannot fit into the mass-action law paradigm and solutions to these systems would frequently exhibit an antiportfolio effect. We provide a complete example application of stochastic kinetics modeling for a deductive meta-analysis of two papers on atrial fibrillation incidence, prevalence, and mortality.

  15. Anthocyanin kinetics are dependent on anthocyanin structure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The kinetics of anthocyanin metabolism was investigated in a human feeding trial. Volunteers (n=12) consumed purple carrots containing five different anthocyanin forms: cyanidin-3-(2”-xylose-6”-glucose-galactoside), cyanidin-3-(2”-xylose-galactoside), cyanidin-3-(2”-xylose-6”-sinapoyl-glucose-galac...

  16. Kinetics of lysosomal storage of indigestible matter.

    PubMed Central

    Hurley, J; Alward, J

    1975-01-01

    In lysosomal storage diseases and in accumulation of lipofusion in the lysosomes there is a gradual eroding of the lysosomal system due to overloading the lysosomes by molecules which cannot be digested or expelled. The kinetics of this accumulation is examined for tissue cultures in terms of the cell growth rate, lysosomal production rate, and of generation of the indigestible element. PMID:1125388

  17. Kinetic equilibria of very high- β plasmas

    NASA Astrophysics Data System (ADS)

    Steinhauer, Loren; TAE Team

    2015-11-01

    Plasma equilibria with many large ion orbits, such as an advanced beam-driven field-reversed configuration, are neither static (Grad-Shafranov) nor describable as a flowing, multi-fluid. A fully-kinetic treatment of the ions is essential for such high- β plasmas. A kinetic equilibrium is needed to properly support realistic stability and transport analyses, both of which are strongly affected by large-orbit ions. A hybrid equilibrium model has been developed with a fully-kinetic treatment of both thermal ions and a rapidly-rotating ``beam-ion'' component, such as produced by neutral beam injection, relevant to the C-2U experiments at TAE. It employs analytic Vlasov solutions in that the distribution depends only on the two constants of motion, the Hamiltonian (H) and the canonical angular momentum (Pθ) . Electrons are treated as a pressure-bearing fluid. Since realistic forms of f (H ,Pθ) are affected by collisions, f is limited to solutions of a simplified Fokker-Planck equation. Importantly, a kinetic end-loss condition applies to unconfined ions, using a particle sink at a rate consistent with Monte-Carlo-like simulations of end loss accounting for a strong end mirror.

  18. Integral kinetic equation in dechanneling problem

    NASA Astrophysics Data System (ADS)

    Ryabov, V.

    1989-11-01

    A version of dechanneling theory, based on using an integral kinetic equation in both the phase and transverse energy space, is described. It is derived from the binary collision model and it takes into account consistently the thermal multiple and single scattering of axial and planar channeled particles. The connection between the method developed and that of Oshiyama and of Gartner is discussed.

  19. KINETICS AND MECHANISMS OF SOIL BIOGEOCHEMICAL PROCESSES

    EPA Science Inventory

    The application of kinetic studies to soil chemistry is useful to determine reaction mechanisms and fate of nutrients and environmental contaminants. How deeply one wishes to query the mechanism depends on the detail sought. Reactions that involve chemical species in more than on...

  20. A microcomputer spreadsheet for aminoglycoside kinetics.

    PubMed

    Kiacz, B J

    1990-05-01

    Development of an aminoglycoside monitoring program need not entail large capital expenditures for pharmacokinetic software. Microsoft's Excel spreadsheet was used to develop a single compartment, first-order kinetics template for individualized aminoglycoside dosing. The formulas employed may be adapted to virtually any other microcomputer spreadsheet package to provide accurate professional results.

  1. Kinetic Analysis of a Mammalian Phospholipase D

    PubMed Central

    Henage, Lee G.; Exton, John H.; Brown, H. Alex

    2013-01-01

    In mammalian cells, phospholipase D activity is tightly regulated by diverse cellular signals, including hormones, neurotransmitters, and growth factors. Multiple signaling pathways converge upon phospholipase D to modulate cellular actions, such as cell growth, shape, and secretion. We examined the kinetics of protein kinase C and G-protein regulation of mammalian phospholipase D1 (PLD1) in order to better understand interactions between PLD1 and its regulators. Activation by Arf-1, RhoA, Rac1, Cdc42, protein kinase Cα, and phosphatidylinositol 4,5-bisphosphate displayed surface dilution kinetics, but these effectors modulated different kinetic parameters. PKCα activation of PLD1 involves N- and C-terminal PLD domains. Rho GTPases were binding activators, enhancing the catalytic efficiency of a purified PLD1 catalytic domain via effects on Km. Arf-1, a catalytic activator, stimulated PLD1 by enhancing the catalytic constant, kcat. A kinetic description of PLD1 activation by multiple modulators reveals a mechanism for apparent synergy between activators. Synergy was observed only when PLD1 was simultaneously stimulated by a binding activator and a catalytic activator. Surprisingly, synergistic activation was steeply dependent on phosphatidylinositol 4,5-bisphosphate and phosphatidylcholine. Together, these findings suggest a role for PLD1 as a signaling node, in which integration of convergent signals occurs within discrete locales of the cellular membrane. PMID:16339153

  2. Kinetic Psychotherapy in the Treatment of Families

    ERIC Educational Resources Information Center

    Schachter, Robert S.

    1978-01-01

    Kinetic Psychotherapy consists of young children's games which facilitate interaction and mobilize feelings. When used as a mode of family therapy, this process enables the therapist to catalize and observe change in the family's patterns of communication, interaction, and level of functioning while involving members in a relatively nonthreatening…

  3. Introducing Michaelis-Menten Kinetics through Simulation

    ERIC Educational Resources Information Center

    Halkides, Christopher J.; Herman, Russell

    2007-01-01

    We describe a computer tutorial that introduces the concept of the steady state in enzyme kinetics. The tutorial allows students to produce graphs of the concentrations of free enzyme, enzyme-substrate complex, and product versus time in order to learn about the approach to steady state. By using a range of substrate concentrations and rate…

  4. Kinetic properties of fractal stellar media

    NASA Astrophysics Data System (ADS)

    Chumak, O. V.; Rastorguev, A. S.

    2017-01-01

    Kinetic processes in fractal stellar media are analysed in terms of the approach developed in our earlier paper involving a generalization of the nearest neighbour and random force distributions to fractal media. Diffusion is investigated in the approximation of scale-dependent conditional density based on an analysis of the solutions of the corresponding Langevin equations. It is shown that kinetic parameters (time-scales, coefficients of dynamic friction, diffusion, etc.) for fractal stellar media can differ significantly both qualitatively and quantitatively from the corresponding parameters for a quasi-uniform random media with limited fluctuations. The most important difference is that in the fractal case, kinetic parameters depend on spatial scalelength and fractal dimension of the medium studied. A generalized kinetic equation for stellar media (fundamental equation of stellar dynamics) is derived in the Fokker-Planck approximation with the allowance for the fractal properties of the spatial stellar density distribution. Also derived are its limit forms that can be used to describe small departures of fractal gravitating medium from equilibrium.

  5. Chemical Kinetic Characterization of Combustion Toluene

    SciTech Connect

    Pitz, W J; Seiser, R; Bozzelli, J W; Da Costa, I; Fournet, R; Billaud, F; Battin-Leclerc, F; Seshadri, K; Westbrook, C K

    2001-03-20

    A study is performed to elucidate the chemical kinetic mechanism of combustion of toluene. A detailed chemical kinetic mechanism for toluene was improved by adding a more accurate description of the phenyl + O{sub 2} reaction channels. Results of the chemical kinetic mechanism are compared with experimental data obtained from premixed and nonpremixed systems. Under premixed conditions, predicted ignition delay times are compared with new experimental data obtained in shock tube. Also, calculated species concentration histories are compared to experimental flow reactor data from the literature. Critical conditions of extinction and ignition were measured in strained laminar flows under nonpremixed conditions in the counterflow configuration. Numerical calculations are performed using the chemical kinetic mechanism at conditions corresponding to those in the experiments. Critical conditions of extinction and ignition are predicted and compared with the experimental data. For both premixed and nonpremixed systems, sensitivity analysis was used to identify the reaction rate constants that control the overall rate of oxidation in each of the systems considered.

  6. Enzyme kinetics of conjugating enzymes: PAPS sulfotransferase.

    PubMed

    James, Margaret O

    2014-01-01

    The sulfotransferase (SULT) enzymes catalyze the formation of sulfate esters or sulfamates from substrates that contain hydroxy or amine groups, utilizing 3'-phosphoadenosyl-5'-phosphosulfate (PAPS) as the donor of the sulfonic group. The rate of product formation depends on the concentrations of PAPS and substrate as well as the sulfotransferase enzyme; thus, if PAPS is held constant while varying substrate concentration (or vice versa), the kinetic constants derived are apparent constants. When studied over a narrow range of substrate concentrations, classic Michaelis-Menten kinetics can be observed with many SULT enzymes and most substrates. Some SULT enzymes exhibit positive or negative cooperativity during conversion of substrate to product, and the kinetics fit the Hill plot. A characteristic feature of most sulfotransferase-catalyzed reactions is that, when studied over a wide range of substrate concentrations, the rate of product formation initially increases as substrate concentration increases, then decreases at high substrate concentrations, i.e., they exhibit substrate inhibition or partial substrate inhibition. This chapter gives an introduction to sulfotransferases, including a historical note, the nomenclature, a description of the function of SULTs with different types of substrates, presentation of examples of enzyme kinetics with SULTs, and a discussion of what is known about mechanisms of substrate inhibition in the sulfotransferases.

  7. KINEXP: Computer Simulation in Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Gelpi, Josep Lluis; Domenech, Carlos

    1988-01-01

    Describes a program which allows students to identify and characterize several kinetic inhibitory mechanisms. Uses the generic model of reversible inhibition of a monosubstrate enzyme but can be easily modified to run other models such as bisubstrate enzymes. Uses MS-DOS BASIC. (MVL)

  8. A Teaching Tool for Molecular Kinetics

    ERIC Educational Resources Information Center

    Imai, Izumi; Kamata, Masahiro; Miura, Naosuke

    2003-01-01

    Kinetic models of a gas can be hard for students to understand. Typical tools do not display events at the microscopic level, yet computer simulations of the molecules lack a hands-on aspect. Here a new tool is described that combines the squeezing of a syringe with a computer simulation, and it is shown that this has worked well in class for both…

  9. Ultracold chemistry and its reaction kinetics

    NASA Astrophysics Data System (ADS)

    Richter, Florian; Becker, Daniel; Bény, Cédric; Schulze, Torben A.; Ospelkaus, Silke; Osborne, Tobias J.

    2015-05-01

    We study the reaction kinetics of chemical processes occurring in the ultracold regime and systematically investigate their dynamics. Quantum entanglement is found to play a key role in driving an ultracold reaction towards a dynamical equilibrium. In case of multiple concurrent reactions Hamiltonian chaos dominates the phase space dynamics in the mean field approximation.

  10. Wave kinetics of random fibre lasers

    PubMed Central

    Churkin, D V.; Kolokolov, I V.; Podivilov, E V.; Vatnik, I D.; Nikulin, M A.; Vergeles, S S.; Terekhov, I S.; Lebedev, V V.; Falkovich, G.; Babin, S A.; Turitsyn, S K.

    2015-01-01

    Traditional wave kinetics describes the slow evolution of systems with many degrees of freedom to equilibrium via numerous weak non-linear interactions and fails for very important class of dissipative (active) optical systems with cyclic gain and losses, such as lasers with non-linear intracavity dynamics. Here we introduce a conceptually new class of cyclic wave systems, characterized by non-uniform double-scale dynamics with strong periodic changes of the energy spectrum and slow evolution from cycle to cycle to a statistically steady state. Taking a practically important example—random fibre laser—we show that a model describing such a system is close to integrable non-linear Schrödinger equation and needs a new formalism of wave kinetics, developed here. We derive a non-linear kinetic theory of the laser spectrum, generalizing the seminal linear model of Schawlow and Townes. Experimental results agree with our theory. The work has implications for describing kinetics of cyclical systems beyond photonics. PMID:25645177

  11. Adsorption Kinetics in Nanoscale Porous Coordination Polymers

    SciTech Connect

    Nune, Satish K.; Thallapally, Praveen K.; McGrail, Benard Peter; Annapureddy, Harsha V. R.; Dang, Liem X.; Mei, Donghai; Karri, Naveen; Alvine, Kyle J.; Olszta, Matthew J.; Arey, Bruce W.; Dohnalkova, Alice

    2015-10-07

    Nanoscale porous coordination polymers were synthesized using simple wet chemical method. The effect of various polymer surfactants on colloidal stability and shape selectivity was investigated. Our results suggest that the nanoparticles exhibited significantly improved adsorption kinetics compared to bulk crystals due to decreased diffusion path lengths and preferred crystal plane interaction.

  12. Kinetic approach for describing biological systems

    NASA Astrophysics Data System (ADS)

    Aristov, V. V.; Ilyin, O. V.

    2016-11-01

    We attempt to consider a biological structure as an open nonequilibrium system the properties of which can be described on the basis of kinetic approach with the help of appropriate kinetic equations. This approach allows us to evaluate in principle scales of sizes and to connect these values to the inner characteristics of the processes of kinetic interaction and advection. One can compare the results with some empirical data concerning these characteristics for bio-systems, in particular mammals, and also for some parts of the systems, say sizes of green leaves. A sense of the nonequilibrium entropy as a measure of complexity of bio-organisms is discussed. Besides the estimations of bio-systems on a global scale, possible methods to describe restricted regions (associated e.g. with living cells) as nonequilibrium open structure with specific boundaries are also discussed. A new boundary 1D problem is formulated and solved for kinetic equations with the membrane-like boundaries conditions. Non-classical transport properties in the system are found.

  13. Kinetic studies on the pyrolysis of pinewood.

    PubMed

    Mishra, Garima; Kumar, Jitendra; Bhaskar, Thallada

    2015-04-01

    The kinetic study for pyrolysis of pine wood has been studied by a thermogravimetric analyzer in an inert atmosphere. Non isothermal model free kinetic methods were used to evaluate kinetics at six different heating rates of 5-40°C/min. Three zones can be detected from the iso-conversional plot of pine with average activation energy values of 134.32 kJ/mol, 146.89 kJ/mol and 155.76 kJ/mol in the conversion range of 1-22%, 24-84% and 85-90%, respectively. The activation energy values were used to determine the reaction mechanism using master plots and compensation parameters. The results show that the pyrolysis process of pine wood can be described by two dimensional diffusion reaction mechanism in a wide range of conversion up to 0.7, followed by close to one and half order reaction mechanism. The kinetic results were validated by making isothermal predictions from non-isothermal data.

  14. Gas phase kinetics during normal combustion

    NASA Technical Reports Server (NTRS)

    Price, C. F.; Boggs, T. L.; Eisel, J. L.; Atwood, A. I.; Zurn, D. E.

    1980-01-01

    The role of gas phase kinetics during combustion was explored in the steady state modeling efforts and in the analysis of ignition phenomena. In both cases it was shown that the combustion characteristics of some high energy ingredients and propellants are strongly affected, if not dictated, by the gas phase reactions which take place.

  15. Kinetic-effect models and their applications.

    PubMed

    Grevel, J

    1987-04-01

    This article focuses on mathematical models that analyze the time course of drug effects in humans. Any such model, whether parametric or nonparametric, is termed a kinetic-effect model (KEM). These models serve to describe (interpolation) and to predict (extrapolation) the effect-time profile. KEMs are applicable to many problems in pharmaceutics, pharmacology, and clinical pharmacology.

  16. Kinetic studies of stress-corrosion cracking

    NASA Technical Reports Server (NTRS)

    Noronha, P. J.

    1977-01-01

    Use of time-to-failure curves for stress-corrosion cracking processes may lead to incorrect estimates of structural life, if material is strongly dependent upon prestress levels. Technique characterizes kinetics of crackgrowth rates and intermediate arrest times by load-level changes.

  17. Production of a sterile species: Quantum kinetics

    SciTech Connect

    Ho, Chiu Man; Boyanovsky, D.; Ho, C.M.

    2007-04-23

    Production of a sterile species is studied within an effective model of active-sterile neutrino mixing in a medium in thermal equilibrium. The quantum kinetic equations for the distribution functions and coherences are obtained from two independent methods: the effective action and the quantum master equation. The decoherence time scale for active-sterile oscillations is tau(dec)=2/Gamma(aa), but the evolution of the distribution functions is determined by the two different time scales associated with the damping rates of the quasiparticle modes in the medium: Gamma(1)=Gamma(aa)cos^2theta(m); Gamma(2)=Gamma(aa)sin^2theta(m) where Gamma(aa) is the interaction rate of the active species in the absence of mixing and theta(m) the mixing angle in the medium. These two time scales are widely different away from Mikheyev-Smirnov-Wolfenstein resonances and preclude the kinetic description of active-sterile production in terms of a simple rate equation. We give the complete set of quantum kinetic equations for the active and sterile populations and coherences and discuss in detail the various approximations. A generalization of the active-sterile transition probability in a medium is provided via the quantum master equation. We derive explicitly the usual quantum kinetic equations in terms of the"polarization vector" and show their equivalence to those obtained from the quantum master equation and effective action.

  18. Kinetic modeling of active plasma resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Oberrath, Jens

    2016-09-01

    The term ``active plasma resonance spectroscopy'' (APRS) refers to a plasma diagnostic method which employs the natural ability of plasmas to resonate close to the plasma frequency. Essential for this method is an appropriate model to determine the relation between the resonance parameters and demanded plasma parameters. Measurements with these probes in plasmas of a few Pa typically show a broadening of the spectrum that cannot be predicted by a fluid model. Thus, a kinetic model is necessary. A general kinetic model of APRS probes, which can be described in electorstatic approximation, valid for all pressures has been presented. This model is used to analyze the dynamic behavior of such probes by means of functional analytic methods. One of the main results is, that the system response function Y (ω) is given in terms of the matrix elements of the resolvent of the dynamic operator evaluated for values on the imaginary axis. The spectrum of this operator is continuous which implies a new phenomenon related to anomalous or non-collisional dissipation. Based on the scalar product, which is motivated by the kinetic free energy, the non-collisional damping can be interpreted: In a periodic state, the probe constantly emits plasma waves which propagate to ``infinity''. The free energy simply leaves the ``observation range'' of the probe which is recorded as damping. The kinetic damping, which depends on the mean kinetic energy of the electrons, is responsible for the broadening of a resonance peak in the measured spectrum of APRS probes. The ultimate goal is to determine explicit formulas for the relation between the broadening of the resonance peak and the ``equivalent electron temperature'', especially in the case of the spherical Impedance Probe and the Multipole Resonance Probe. Gratitude is expressed to the internal funding of Leuphana University, the BMBF via PluTO+, the DFG via Collaborative Research Center TR 87, and the Ruhr University Research School.

  19. Protein Fibrillation Lag Times During Kinetic Inhibition

    PubMed Central

    Pagano, Rodrigo S.; López Medus, Máximo; Gómez, Gabriela E.; Couto, Paula M.; Labanda, María S.; Landolfo, Lucas; D’Alessio, Cecilia; Caramelo, Julio J.

    2014-01-01

    Protein aggregation is linked to more than 30 human pathologies, including Alzheimer’s and Parkinson’s diseases. Since small oligomers that form at the beginning of the fibrillation process probably are the most toxic elements, therapeutic strategies involving fibril fragmentation could be detrimental. An alternative approach, named kinetic inhibition, aims to prevent fibril formation by using small ligands that stabilize the parent protein. The factors that govern fibrillation lag times during kinetic inhibition are largely unknown, notwithstanding their importance for designing effective long-term therapies. Inhibitor-bound species are not likely to be incorporated into the core of mature fibrils, although their presence could alter the kinetics of the fibrillation process. For instance, inhibitor-bound species may act as capping elements that impair the nucleation process and/or fibril growth. Here, we address this issue by studying the effect of two natural inhibitors on the fibrillation behavior of lysozyme at neutral pH. We analyzed a set of 79 fibrillation curves obtained in lysozyme alone and a set of 37 obtained in the presence of inhibitors. We calculated the concentrations of the relevant species at the beginning of the curves using the inhibitor-binding constants measured under the same experimental conditions. We found that inhibitor-bound protein species do not affect fibrillation onset times, which are mainly determined by the concentration of unbound protein species present in equilibrium. In this system, knowledge of the fibrillation kinetics and inhibitor affinities suffices to predict the effect of kinetic inhibitors on fibrillation lag times. In addition, we developed a new methodology to better estimate fibrillation lag times from experimental curves. PMID:25099810

  20. Preformed Seeds Modulate Native Insulin Aggregation Kinetics.

    PubMed

    Dutta, Colina; Yang, Mu; Long, Fei; Shahbazian-Yassar, Reza; Tiwari, Ashutosh

    2015-12-10

    Insulin aggregates under storage conditions via disulfide interchange reaction. It is also known to form aggregates at the site of repeated injections in diabetes patients, leading to injection amyloidosis. This has fueled research in pharmaceutical and biotechnology industry as well as in academia to understand factors that modulate insulin stability and aggregation. The main aim of this study is to understand the factors that modulate aggregation propensity of insulin under conditions close to physiological and measure effect of "seeds" on aggregation kinetics. We explored the aggregation kinetics of insulin at pH 7.2 and 37 °C in the presence of disulfide-reducing agent dithiothreitol (DTT), using spectroscopy (UV-visible, fluorescence, and Fourier transform infrared spectroscopy) and microscopy (scanning electron microscopy, atomic force microscopy) techniques. We prepared insulin "seeds" by incubating disulfide-reduced insulin at pH 7.2 and 37 °C for varying lengths of time (10 min to 12 h). These seeds were added to the native protein and nucleation-dependent aggregation kinetics was measured. Aggregation kinetics was fastest in the presence of 10 min seeds suggesting they were nascent. Interestingly, intermediate seeds (30 min to 4 h incubation) resulted in formation of transient fibrils in 4 h that converted to amorphous aggregates upon longer incubation of 24 h. Overall, the results show that insulin under disulfide reducing conditions at pH and temperature close to physiological favors amorphous aggregate formation and seed "maturity" plays an important role in nucleation dependent aggregation kinetics.

  1. A kinetic equation with kinetic entropy functions for scalar conservation laws

    NASA Technical Reports Server (NTRS)

    Perthame, Benoit; Tadmor, Eitan

    1990-01-01

    A nonlinear kinetic equation is constructed and proved to be well-adapted to describe general multidimensional scalar conservation laws. In particular, it is proved to be well-posed uniformly in epsilon - the microscopic scale. It is also shown that the proposed kinetic equation is equipped with a family of kinetic entropy functions - analogous to Boltzmann's microscopic H-function, such that they recover Krushkov-type entropy inequality on the macroscopic scale. Finally, it is proved by both - BV compactness arguments in the one-dimensional case, that the local density of kinetic particles admits a continuum limit, as it converges strongly with epsilon below 0 to the unique entropy solution of the corresponding conservation law.

  2. Alkylation of Chlorobenzene. An Experiment Illustrating Kinetic versus Thermodynamic Control.

    ERIC Educational Resources Information Center

    Kolb, Kenneth; And Others

    1988-01-01

    Describes an experiment which illustrates the kinetic versus thermodynamic control of chemical reactions for organic chemistry students. Considers the laboratory procedures including the isolation of both the kinetic and thermodynamic products. (CW)

  3. Thermodynamics and Kinetics of Chemical Equilibrium in Solution.

    ERIC Educational Resources Information Center

    Leenson, I. A.

    1986-01-01

    Discusses theory of thermodynamics of the equilibrium in solution and dissociation-dimerization kinetics. Describes experimental procedure including determination of molar absorptivity and equilibrium constant, reaction enthalpy, and kinetics of the dissociation-dimerization reaction. (JM)

  4. An Intuitive Approach to Steady-State Kinetics.

    ERIC Educational Resources Information Center

    Raines, Ronald T.; Hansen, David E.

    1988-01-01

    Attempts to provide an intuitive understanding of steady state kinetics. Discusses the meaning of steady state and uses free energy profiles to illustrate and follow complex kinetic and thermodynamic relationships. Provides examples with explanations. (MVL)

  5. 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, C. J.; Hindley, N. P.; Moss, A. C.; Mitchell, N. J.

    2015-07-01

    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 (MLS-Aura, HIRDLS and SABER), the COSMIC GPS-RO constellation, a ground-based meteor radar, the 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. 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 datasets, suggesting very different behaviour of the wave field in the different spectral regimes accessed by each instrument. Except in spring, we see little dissipation of GWPE throughout the stratosphere and lower mesosphere. Observed GWPE for individual wave packets exhibits a log-normal distribution, with short-timescale intermittency dominating over a well-repeated monthly-median seasonal cycle. GWPE and λz exhibit strong correlations with the stratospheric winds, but not with local surface winds. Our results provide guidance for interpretation and intercomparison of such datasets in their full

  6. Mathematics analysis of polymerase chain reaction kinetic curves.

    PubMed

    Sochivko, D G; Fedorov, A A; Varlamov, D A; Kurochkin, V E; Petrov, R V

    2016-01-01

    The paper reviews different approaches to the mathematical analysis of polymerase chain reaction (PCR) kinetic curves. The basic principles of PCR mathematical analysis are presented. Approximation of PCR kinetic curves and PCR efficiency curves by various functions is described. Several PCR models based on chemical kinetics equations are suggested. Decision criteria for an optimal function to describe PCR efficiency are proposed.

  7. [Kinetics of conformational changes of methemoglobin complexed with liposomes].

    PubMed

    Gorbenko, G P

    1998-01-01

    Kinetics of methemoglobin structural changes in the complex with liposomes composed of phosphatidylcholine and its mixtures with cardiolipin has been studied. The amplitudes and rate constants of the two observed kinetic phases are determined. The fast kinetic phase is attributed to the formation of the unstable intermediate protein form, while the slow one is assumed to reflect dissociation of the heme--globin complex.

  8. Model-based analysis of coupled equilibrium-kinetic processes: indirect kinetic studies of thermodynamic parameters using the dynamic data.

    PubMed

    Emami, Fereshteh; Maeder, Marcel; Abdollahi, Hamid

    2015-05-07

    Thermodynamic studies of equilibrium chemical reactions linked with kinetic procedures are mostly impossible by traditional approaches. In this work, the new concept of generalized kinetic study of thermodynamic parameters is introduced for dynamic data. The examples of equilibria intertwined with kinetic chemical mechanisms include molecular charge transfer complex formation reactions, pH-dependent degradation of chemical compounds and tautomerization kinetics in micellar solutions. Model-based global analysis with the possibility of calculating and embedding the equilibrium and kinetic parameters into the fitting algorithm has allowed the complete analysis of the complex reaction mechanisms. After the fitting process, the optimal equilibrium and kinetic parameters together with an estimate of their standard deviations have been obtained. This work opens up a promising new avenue for obtaining equilibrium constants through the kinetic data analysis for the kinetic reactions that involve equilibrium processes.

  9. Kinetic titration series with biolayer interferometry.

    PubMed

    Frenzel, Daniel; Willbold, Dieter

    2014-01-01

    Biolayer interferometry is a method to analyze protein interactions in real-time. In this study, we illustrate the usefulness to quantitatively analyze high affinity protein ligand interactions employing a kinetic titration series for characterizing the interactions between two pairs of interaction patterns, in particular immunoglobulin G and protein G B1 as well as scFv IC16 and amyloid beta (1-42). Kinetic titration series are commonly used in surface plasmon resonance and involve sequential injections of analyte over a desired concentration range on a single ligand coated sensor chip without waiting for complete dissociation between the injections. We show that applying this method to biolayer interferometry is straightforward and i) circumvents problems in data evaluation caused by unavoidable sensor differences, ii) saves resources and iii) increases throughput if screening a multitude of different analyte/ligand combinations.

  10. Inflation Rates, Car Devaluation, and Chemical Kinetics

    NASA Astrophysics Data System (ADS)

    Pogliani, Lionello; Berberan-Santos, Màrio N.

    1996-10-01

    The inflation rate problem of a modern economy shows quite interesting similarities with chemical kinetics and especially with first-order chemical reactions. In fact, capital devaluation during periods of rather low inflation rates or inflation measured over short periods shows a dynamics formally similar to that followed by first-order chemical reactions and they can thus be treated by the aid of the same mathematical formalism. Deviations from this similarity occurs for higher inflation rates. The dynamics of price devaluation for two different types of car, a compact car and a luxury car, has been followed for seven years long and it has been established that car devaluation is a process that is formally similar to a zeroth-order chemical kinetic process disregarding the type of car, if car devaluation is much faster than money devaluation. In fact, expensive cars devaluate with a faster rate than inexpensive cars.

  11. Kinetic study and mechanism of Niclosamide degradation

    NASA Astrophysics Data System (ADS)

    Zaazaa, Hala E.; Abdelrahman, Maha M.; Ali, Nouruddin W.; Magdy, Maimana A.; Abdelkawy, M.

    2014-11-01

    A spectrophotometric kinetic study of Niclosamide alkaline degradation as a function of drug concentration, alkaline concentration and temperature has been established utilizing double divisor-ratio spectra spectrophotometric method. The developed method allowed determination of Niclosamide in presence of its alkaline degradation products; namely; 2-chloro-4-nitro aniline (DEG I) and 5-chloro salicylic acid (DEG II) with characterization of its degradation mechanism. It was found that degradation kinetic of Niclosamide followed pseudo-first order under the established experimental conditions with a degradation rate constant (k) of 0.0829 mol/h and half life (t1/2) of 8.35 h. The overall degradation rate constant as a function of the temperature under the given conditions obeyed Arrhenius equation where the activation energy was calculated to be 3.41 kcal/mol.

  12. Adsorption kinetics of silicic acid on akaganeite.

    PubMed

    Naren, Gaowa; Ohashi, Hironori; Okaue, Yoshihiro; Yokoyama, Takushi

    2013-06-01

    As part of a series of studies on the interaction between ferric ions and silicic acid in the hydrosphere, the adsorption of silicic acid on akaganeite was investigated kinetically at various pH values. The adsorption of silicic acid increased with increasing pH over an initial pH range of 4-11.5. In the kinetic experiment, the Cl(-) was released from akaganeite much faster than silicic acid was adsorbed. From this result, we concluded that chloride ions bound on the surface of akaganeite are released and Fe-OH or Fe-O(-) sites are formed, which then acts as an adsorption site for silicic acid. The uptake mechanism of silicic acid by akaganeite is significantly different from that by schwertmannite, despite the presence of the same tunnel structure.

  13. Mean-field kinetic nucleation theory

    NASA Astrophysics Data System (ADS)

    Kalikmanov, V. I.

    2006-03-01

    A new semiphenomenological model of homogeneous vapor-liquid nucleation is proposed in which the cluster kinetics follows the "kinetic approach to nucleation" and the thermodynamic part is based on the revised Fisher droplet model with the mean-field argument for the cluster configuration integral. The theory is nonperturbative in a cluster size and as such is valid for all clusters down to monomers. It contains two surface tensions: macroscopic (planar) and microscopic. The latter is a temperature dependent quantity related to the vapor compressibility factor at saturation. For Lennard-Jones fluids the microscopic surface tension possesses a universal behavior with the parameters found from the mean-field density functional calculations. The theory is verified against nucleation experiments for argon, nitrogen, water, and mercury, demonstrating very good agreement with experimental data. Classical nucleation theory fails to predict experimental results when a critical cluster becomes small.

  14. Imaging neurotransmitter release kinetics in living cells

    SciTech Connect

    Tan, Weihong; Yeung, E.S.; Haydon, P.G.

    1996-12-31

    A new UV-laser based optical microscope and CCD detection system has been developed to image neurotransmitter in living biological cells. We demonstrate the detection of serotonin that has been taken up into and released from individual living glial cells (astrocytes) based on its native fluorescence. The detection methodology has high sensitivity, low limit of detection and does not require coupling to fluorescence dyes. We have studied serotonin uptake kinetics and its release dynamics in single glial cells. Different regions of a glial cell have taken up different amounts of serotonin with a variety of kinetics. Similarly, different serotonin release mechanisms have been observed in different astrocyte cell regions. The temporal resolution of this detection system is as fast as 50 ms, and the spatial resolution is diffraction limited. We will also report on single enzyme molecule reaction studies and single metal ion detection based on CCD imaging of pL reaction vials formed by micromachining on fused silica.

  15. Processes of aggression described by kinetic method

    SciTech Connect

    Aristov, V. V.; Ilyin, O.

    2014-12-09

    In the last decades many investigations have been devoted to theoretical models in new areas concerning description of different biological, sociological and historical processes. In the present paper we suggest a model of the Nazi Germany invasion of Poland, France and USSR based on the kinetic theory. We model this process with the Cauchy boundary problem for the two-element kinetic equations with spatial initial conditions. The solution of the problem is given in the form of traveling wave. The propagation velocity of a frontline depends on the quotient between initial forces concentrations. Moreover it is obtained that the general solution of the model can be expressed in terms of quadratures and elementary functions. Finally it is shown that the frontline velocities are complied with the historical data.

  16. Sigmoid kinetics of protein crystal nucleation

    NASA Astrophysics Data System (ADS)

    Nanev, Christo N.; Tonchev, Vesselin D.

    2015-10-01

    A non-linear differential equation expressing the new phase nucleation rate in the different steps of the process (non-stationary and stationary nucleation and in the plateau region) is derived from basic principles of the nucleation theory. It is shown that one and the same sigmoid (logistic) function describes both nucleation scenarios: the one according to the classical theory, and the other according to the modern two-stage mechanism of protein crystal formation. Comparison to experimental data on both insulin crystal nucleation kinetics and on bovine β-lactoglobulin crystallization indicates a good agreement with the sigmoidal prediction. Experimental data for electrochemical nucleation and glass crystallization obey the same sigmoid time dependence, and suggest universality of this nucleation kinetics law.

  17. Kinetics of crystallization of igneous rocks

    SciTech Connect

    Kirkpatrick, R.J.

    1981-01-01

    The geochemistry of igneous rocks is discussed, with the primary objectives of bringing together the theories underlying the kinetics of crystallization of igneous rocks and illustrating the use of these theories in understanding experimental and observational data. The primary purpose of the chapter is to introduce current thinking about the kinetics of igneous rocks and to provide a basis for understanding other work. A basic assumption made in the discussion is that the rate of any chemical reaction, including the crystallization of igneous rocks, is zero at equilibrium and proceeds at a finite rate only at a finite deviation from equilibrium. As such, an understanding of the processes operating in igneous rocks requires an understanding of how deviation from equilibrium affects the rates and mechanisms of the processes occurring during crystallization. These processes are detailed, with special emphasis given to nucleation and crystal growth. (JMT)

  18. On the kinetic foundations of Kaluza's magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Sandoval-Villalbazo, Alfredo; Sagaceta-Mejía, Alma R.; García-Perciante, Ana L.

    2015-06-01

    Recent work has shown the existence of a relativistic effect present in a single component non-equilibrium fluid, corresponding to a heat flux due to an electric field [J. Non-Equilib. Thermodyn. 38 (2013), 141-151]. The treatment in that work was limited to a four-dimensional Minkowski space-time in which the Boltzmann equation was treated in a special relativistic approach. The more complete framework of general relativity can be introduced to kinetic theory in order to describe transport processes associated to electromagnetic fields. In this context, the original Kaluza's formalism is a promising approach [Sitz. Ber. Preuss. Akad. Wiss. (1921), 966-972; Gen. Rel. Grav. 39 (2007), 1287-1296; Phys. Plasmas 7 (2000), 4823-4830]. The present work contains a kinetic theory basis for Kaluza's magnetohydrodynamics and gives a novel description for the establishment of thermodynamic forces beyond the special relativistic description.

  19. The Kinetic Chain in Overhand Pitching

    PubMed Central

    Seroyer, Shane T.; Nho, Shane J.; Bach, Bernard R.; Bush-Joseph, Charles A.; Nicholson, Gregory P.; Romeo, Anthony A.

    2010-01-01

    The overhead throwing motion is a coordinated effort of muscle units from the entire body, culminating with explosive motion of the upper extremity. The throwing motion occurs at a rapid pace, making analysis difficult in real time. Electromyographic studies and high-speed video recordings have provided invaluable details regarding the involved musculature, the sequence of muscle involvement, and associated kinematic variables. The goal of the present article is to provide an overview of the kinetic chain—that is, a detailed description of the muscular coordination during each phase of pitching—and to describe specific types of pitches. An enhanced understanding of the components of the kinetic chain and the phases of the throwing motion can provide important information for rehabilitation, performance enhancement, and injury prevention. PMID:23015931

  20. Kinetics of noradrenaline released by sympathetic nerves.

    PubMed

    Gonon, F; Msghina, M; Stjärne, L

    1993-10-01

    At the skeletal neuromuscular junction the released neurotransmitter, acetylcholine, is eliminated within some milliseconds. This time course is known with great precision through the electrical response of target cells. At the sympathetic neuroeffector junction the fast electrical response is not mediated by noradrenaline but by a cotransmitter: ATP. The slow electrical response and the slow component of smooth muscle contraction are principally mediated by noradrenaline. These responses are two orders of magnitude slower than the electrical response to ATP. Therefore, great uncertainty remains regarding the kinetics of noradrenaline appearance and elimination. Here, the local noradrenaline concentration at the surface of the isolated rat tail artery was electrochemically monitored in real time using a carbon fibre electrode. We have shown that the time course of the neurogenically released noradrenaline is at least one order of magnitude faster than the resulting contraction. The kinetics of noradrenaline inactivation by neuronal reuptake were also precisely measured.

  1. Positron kinetics in an idealized PET environment

    NASA Astrophysics Data System (ADS)

    Robson, R. E.; Brunger, M. J.; Buckman, S. J.; Garcia, G.; Petrović, Z. Lj.; White, R. D.

    2015-08-01

    The kinetic theory of non-relativistic positrons in an idealized positron emission tomography PET environment is developed by solving the Boltzmann equation, allowing for coherent and incoherent elastic, inelastic, ionizing and annihilating collisions through positronium formation. An analytic expression is obtained for the positronium formation rate, as a function of distance from a spherical source, in terms of the solutions of the general kinetic eigenvalue problem. Numerical estimates of the positron range - a fundamental limitation on the accuracy of PET, are given for positrons in a model of liquid water, a surrogate for human tissue. Comparisons are made with the ‘gas-phase’ assumption used in current models in which coherent scattering is suppressed. Our results show that this assumption leads to an error of the order of a factor of approximately 2, emphasizing the need to accurately account for the structure of the medium in PET simulations.

  2. The Kinetics of Forisome Conformation Change

    NASA Astrophysics Data System (ADS)

    Warmann, Stephen; Pickard, William

    2005-11-01

    Forisomes are a newly discovered proteinaceous contractile element found in the phloem of legumes. These protein bodies show promise as a biological smart material. Forisomes contract anisotropically in response to pH variation or the presence of calcium ions. Possible applications of forisomes include micro-valves, micro-actuators, and other smart sensing activities where one may currently see materials such as synthetic hydrogels or shape memory alloys. In order to pursue forisome synthesis as a smart material and to understand the biological function of the forisome, a detailed understanding of its material properties is necessary. Our research in this area entails the study of the mechanical properties and surface interactions of forisomes. Here we present detailed conformational kinetics of forisomes from Vicia faba, Glycine max, and Canavalia gladiata. The flow rate dependency of conformational kinetics within a microfluidic network is described. Computational fluid dynamic models of the phloem are presented.

  3. Density Scaling of Noninteracting Kinetic Energy Functionals.

    PubMed

    Borgoo, Alex; Tozer, David J

    2013-05-14

    The influence of imposing an approximate density scaling condition on a noninteracting kinetic energy functional is investigated. A simple generalized gradient approximation (GGA) is presented, which satisfies both the density scaling condition and the usual coordinate scaling condition; the remaining multiplicative constant is determined from an energy criterion. In post-Kohn-Sham calculations, noninteracting kinetic energies of the closed-shell molecules of the G1 set determined using the GGA are a modest improvement over those determined using the corresponding local functional, which does not satisfy the density scaling condition. Potential energy curves of CO, F2, and P2 exhibit binding with the GGA, compared to purely repulsive curves with the local functional. Adjusting the exponent in the GGA form in order to optimize energy accuracy violates the density scaling condition, and two of the diatomics no longer exhibit binding. Results are compared with those from other local/GGA functionals in the literature.

  4. Kinetics of ethanol inhibition in alcohol fermentation.

    PubMed

    Luong, J H

    1985-03-01

    The inhibitory effect of ethanol on yeast growth and fermentation has been studied for the strain Saccharomyces cerevisiae ATCC No. 4126 under anaerobic batch conditions. The results obtained reveal that there is no striking difference between the response of growth and ethanol fermentation. Two kinetic models are also proposed to describe the kinetic pattern of ethanol inhibition on the specific rates of growth and ethanol fermentation: microi/micro0 = 1 - (P/Pm)alpha (for growth) nui/nu0 = 1 - (P/P'm)beta (for ethanol production). The maximum allowable ethanol concentration above which cells do not grow was predicted to be 112 g/L. The ethanol-producing capability of the cells was completely inhibited at 115 g/L ethanol. The proposed models appear to accurately represent the experimental data obtained in this study and the literature data.

  5. Kinetics of ethanol inhibition in alcohol fermentation

    SciTech Connect

    Luong, J.H.T.

    1985-01-01

    The inhibitory effect of ethanol on yeast growth and fermentation has been studied for the strain Saccharo-myces cerevisiae ATCC No. 4126 under anaerobic batch conditions. The results obtained reveal that there is no striking difference between the response of growth and ethanol fermentation. Two kinetic models are also proposed to describe the kinetic pattern of ethanol inhibition on the specific rates of growth and ethanol fermentation. The maximum allowable ethanol concentration above which cells do not grow was predicted to be 112 g/L. The ethanol-producing capability of the cells was completely inhibited at 115 g/L ethanol. The proposed models appear to accurately represent the experimental data obtained in this study and the literature data.

  6. The kinetics of sulfation of calcium oxide

    SciTech Connect

    Sarofim, A.F.; Longwell, J.P.

    1990-03-28

    The objectives of this study are to determine the intrinsic kinetics and the product layer diffusion rate by minimizing the resistances to gas-phase pore diffusion, and eliminating complications due to pore filling. In the report, a grain model was used to introduce the various potentially rate-limiting processes. It was compared with results obtained with a distributed pore model by Bhatia Perlmutter (1981). Comparing the predicted behavior of the surface areas with conversion, it was even possible to compare experimental results with other models. The conclusion of this study was that, even thought the kinetic parameters obtained with different samples differed much more if product layer diffusion assumed rate-limiting rather than the surface reaction, the shape of the predicted curve approached the experimental findings so much better, that product layer diffusion is indeed most likely to be rate-limiting. (VC)

  7. Kinetic study and mechanism of Niclosamide degradation.

    PubMed

    Zaazaa, Hala E; Abdelrahman, Maha M; Ali, Nouruddin W; Magdy, Maimana A; Abdelkawy, M

    2014-11-11

    A spectrophotometric kinetic study of Niclosamide alkaline degradation as a function of drug concentration, alkaline concentration and temperature has been established utilizing double divisor-ratio spectra spectrophotometric method. The developed method allowed determination of Niclosamide in presence of its alkaline degradation products; namely; 2-chloro-4-nitro aniline (DEG I) and 5-chloro salicylic acid (DEG II) with characterization of its degradation mechanism. It was found that degradation kinetic of Niclosamide followed pseudo-first order under the established experimental conditions with a degradation rate constant (k) of 0.0829 mol/h and half life (t1/2) of 8.35 h. The overall degradation rate constant as a function of the temperature under the given conditions obeyed Arrhenius equation where the activation energy was calculated to be 3.41 kcal/mol.

  8. Processes of aggression described by kinetic method

    NASA Astrophysics Data System (ADS)

    Aristov, V. V.; Ilyin, O.

    2014-12-01

    In the last decades many investigations have been devoted to theoretical models in new areas concerning description of different biological, sociological and historical processes. In the present paper we suggest a model of the Nazi Germany invasion of Poland, France and USSR based on the kinetic theory. We model this process with the Cauchy boundary problem for the two-element kinetic equations with spatial initial conditions. The solution of the problem is given in the form of traveling wave. The propagation velocity of a frontline depends on the quotient between initial forces concentrations. Moreover it is obtained that the general solution of the model can be expressed in terms of quadratures and elementary functions. Finally it is shown that the frontline velocities are complied with the historical data.

  9. Kinetics of thermal donor generation in silicon

    NASA Technical Reports Server (NTRS)

    Mao, B.-Y.; Lagowski, J.; Gatos, H. C.

    1984-01-01

    The generation kinetics of thermal donors at 450 C in Czochralski-grown silicon was found to be altered by high-temperature preannealing (e.g., 1100 C for 30 min). Thus, when compared with as-grown Si, high-temperature preannealed material exhibits a smaller concentration of generated thermal donors and a faster thermal donor saturation. A unified mechanism of nucleation and oxygen diffusion-controlled growth (based on solid-state plate transformation theory) is proposed to account for generation kinetics of thermal donors at 450 C, in as-grown and high-temperature preannealed Czochralski silicon crystals. This mechanism is consistent with the main features of the models which have been proposed to explain the formation of oxygen thermal donors in silicon.

  10. Influence of surface charge on wetting kinetics.

    PubMed

    Puah, Lee San; Sedev, Rossen; Fornasiero, Daniel; Ralston, John; Blake, Terry

    2010-11-16

    The wettability of a titania surface, partially covered with octadecyltrihydrosilane, has been investigated as a function of solution pH. The results show that surface charge affects both static wettability and wetting kinetics. The static contact angle decreases above and below the point of zero charge of the titania surface in a Lippman-like manner as the pH is altered. The dependence of dynamic contact angle on velocity is also affected by pH. The molecular-kinetic theory (MKT) is used to interpret the dynamic contact angle data. The frequency of molecular displacement κ(0) strongly varies with surface charge, whereas the mean molecular displacement length λ is essentially unaffected. There is an exponential dependence of contact-line friction upon work of adhesion, which is varied simply by altering the pH.

  11. Kinetic Models with Randomly Perturbed Binary Collisions

    NASA Astrophysics Data System (ADS)

    Bassetti, Federico; Ladelli, Lucia; Toscani, Giuseppe

    2011-02-01

    We introduce a class of Kac-like kinetic equations on the real line, with general random collisional rules which, in some special cases, identify models for granular gases with a background heat bath (Carrillo et al. in Discrete Contin. Dyn. Syst. 24(1):59-81, 2009), and models for wealth redistribution in an agent-based market (Bisi et al. in Commun. Math. Sci. 7:901-916, 2009). Conditions on these collisional rules which guarantee both the existence and uniqueness of equilibrium profiles and their main properties are found. The characterization of these stationary states is of independent interest, since we show that they are stationary solutions of different evolution problems, both in the kinetic theory of rarefied gases (Cercignani et al. in J. Stat. Phys. 105:337-352, 2001; Villani in J. Stat. Phys. 124:781-822, 2006) and in the econophysical context (Bisi et al. in Commun. Math. Sci. 7:901-916, 2009).

  12. Crystallization kinetics of citric acid anhydrate

    NASA Astrophysics Data System (ADS)

    Nemdili, L.; Koutchoukali, O.; Bouhelassa, M.; Seidel, J.; Mameri, F.; Ulrich, J.

    2016-10-01

    The solubility curve, metastable zone width (MSZW) and Crystallization kinetics (nucleation and growth) were measured and estimated during batch crystallization of citric acid anhydrate (CAA). The solubility of citric acid in pure water was measured over the temperature range from 15 to 60 °C using a refractometer. The experimental data were correlated by the modified Apelblat equation. The MSZW was determined under four cooling rates for different citric acid concentrations by means of an ultrasonic technique. The primary nucleation kinetics of CAA was calculated based on these data and the polythermal method of Nyvlt. It was found that the MSZW obtained is in good agreement with literature. Crystal growth rates were calculated by two methods. The first one used seeded isothermal growth experiments (desupersaturation curve) and the derivatives method of Garside. The second method used the measurement of the dimension change of a single crystal in a microscopic cell at different supersaturation levels.

  13. Growth and dissolution kinetics of tetragonal lysozyme

    NASA Technical Reports Server (NTRS)

    Monaco, L. A.; Rosenberger, F.

    1993-01-01

    The growth and dissolution kinetics of lysozyme in a 25 ml solution bridge inside a closed growth cell was investigated. It was found that, under all growth conditions, the growth habit forming (110) and (101) faces grew through layer spreading with different growth rate dependence on supersaturation/temperature. On the other hand, (100) faces which formed only at low temperatures underwent a thermal roughening transition around 12 C.

  14. Optical and Kinetic Processes in Excimer Lasers

    DTIC Science & Technology

    1993-03-01

    investigations of the spectroscopy and chemical kinetics of XeF and XeCl lasers using theoretical techniques , synchrotron radiation excitation, and laser... technique for characterizing potential SBS media. Our work is described in Appendices N and 0. 3 OTHER TOPICS IN LASERS AND NONLINEAR OPTICS The SRS and... technique described above for several fluorine and chlorine donors are shown in Table 1. The quanitities in parentheses indicate where the yields have

  15. Excess kinetic energy dissipation in materials

    SciTech Connect

    Corrales, Louis R.; Chartier, Alain; Devanathan, Ram

    2005-01-12

    Molecular dynamics computer simulations are used to study the evolution of thermal spikes arising from PKAs in zircon and copper. The effects of thermostats employed to remove energy from the system is characterized and compared to the case where kinetic energy is not removed from the system. Strong effects on the trajectory of the collision sequence is found for zircon, but in contrast, little effects are found for copper.

  16. Kinetically Distinguishable Populations of Phytochrome 1

    PubMed Central

    Purves, William K.; Briggs, Winslow R.

    1968-01-01

    Two or more kinetically distinguishable populations of phytochrome molecules were observed in living tissues of oat, pea, maize, and cauliflower, as well as in extracts of oat. At least 3 different populations occurred in cauliflower florets, while 2 were observed in each of the other species. In extracted oat phytochrome, the relative proportions of the 2 forms remained constant during successive stages of purification. The physiological significance of this multiplicity of forms remains unclear. PMID:16656909

  17. Reduced methanol kinetic mechanisms for combustion applications

    SciTech Connect

    Yalamanchili, S.; Sirignano, W.A.; Seiser, R.; Seshadri, K.

    2005-08-01

    Reduced chemical kinetic mechanisms for methanol combustion were investigated by evaluating ignition delay magnitudes and combustion in a continuously stirred reactor. Unsteady computations were made to study the characteristics of the kinetic mechanisms proposed in the literature and to compare the dependence of various parameters on methanol combustion. All computations were done under isobaric conditions, and, to capture the influence of all the reactions involved in the mechanism, a very small time step was used. Finite-difference methods were used to solve the coupled differential equations. The five-step mechanism developed by C.M. Mueller and N. Peters [in: N. Peters, B. Rogg (Eds.), Reduced Kinetic Mechanisms for Applications in Combustion Systems, Springer-Verlag, New York, 1993, pp. 143-155] for premixed flames and both the five-step mechanism and the four-step mechanisms developed by C.M. Mueller, K. Seshadri, J.Y. Chen [ibid, pp. 284-307] for non-premixed flames were considered. It was found that the Mueller et al. five-step mechanism, with some modifications, best supported the spontaneous ignition and continuous stirred reactor combustion. The results were validated by comparing calculated ignition delays with available experimental data of C.T. Bowman [Combust. Flame 25 (1975) 343-354], and calculated final steady-state concentrations with chemical equilibrium calculations [J.-Y. Chen, Combust. Sci. Technol. 78 (1991) 127]. Initial temperature and concentration and the operating pressure of the system have a major effect on the delay of methanol ignition. The residence time of the continuous stirred reactor affects ignition delay and also changes the transient characteristic of chemical composition of the fuel-vapor mixture. The computations are intended to guide and explain many combustion studies that require a methanol kinetic mechanism.

  18. Kinetics model development of cocoa bean fermentation

    NASA Astrophysics Data System (ADS)

    Kresnowati, M. T. A. P.; Gunawan, Agus Yodi; Muliyadini, Winny

    2015-12-01

    Although Indonesia is one of the biggest cocoa beans producers in the world, Indonesian cocoa beans are oftenly of low quality and thereby frequently priced low in the world market. In order to improve the quality, adequate post-harvest cocoa processing techniques are required. Fermentation is the vital stage in series of cocoa beans post harvest processing which could improve the quality of cocoa beans, in particular taste, aroma, and colours. During the fermentation process, combination of microbes grow producing metabolites that serve as the precursors for cocoa beans flavour. Microbial composition and thereby their activities will affect the fermentation performance and influence the properties of cocoa beans. The correlation could be reviewed using a kinetic model that includes unstructured microbial growth, substrate utilization and metabolic product formation. The developed kinetic model could be further used to design cocoa bean fermentation process to meet the expected quality. Further the development of kinetic model of cocoa bean fermentation also serve as a good case study of mixed culture solid state fermentation, that has rarely been studied. This paper presents the development of a kinetic model for solid-state cocoa beans fermentation using an empirical approach. Series of lab scale cocoa bean fermentations, either natural fermentations without starter addition or fermentations with mixed yeast and lactic acid bacteria starter addition, were used for model parameters estimation. The results showed that cocoa beans fermentation can be modelled mathematically and the best model included substrate utilization, microbial growth, metabolites production and its transport. Although the developed model still can not explain the dynamics in microbial population, this model can sufficiently explained the observed changes in sugar concentration as well as metabolic products in the cocoa bean pulp.

  19. Chemical Kinetic Models for Advanced Engine Combustion

    SciTech Connect

    Pitz, William J.; Mehl, Marco; Westbrook, Charles K.

    2014-10-22

    The objectives for this project are as follows: Develop detailed chemical kinetic models for fuel components used in surrogate fuels for compression ignition (CI), homogeneous charge compression ignition (HCCI) and reactivity-controlled compression-ignition (RCCI) engines; and Combine component models into surrogate fuel models to represent real transportation fuels. Use them to model low-temperature combustion strategies in HCCI, RCCI, and CI engines that lead to low emissions and high efficiency.

  20. Gas-Phase Theoretical Kinetics for Astrochemistry

    NASA Astrophysics Data System (ADS)

    Klippenstein, Stephen

    2013-05-01

    We will survey a number of our applications of ab initio theoretical kinetics to reactions of importance to astrochemistry. Illustrative examples will be taken from our calculations for (i) interstellar chemistry, (ii) Titan's atmospheric chemistry, and (iii) the chemistry of extrasolar giant planets. For low temperature interstellar chemistry, careful consideration of the long-range expansion of the potential allows for quantitative predictions of the kinetics. Our recent calculations for the reactions of H3+ with O(3P) and with CO suggest an increase of the predicted destruction rate of H3+ by a factor of 2.5 to 3.0 for temperatures that are typical of dense clouds. Further consideration of the interplay between spin-orbit and multipole terms for open-shell atomic fragments allows us to predict the kinetics for a number of the reactions that have been listed as important reactions for interstellar chemical modeling [V. Wakelam, I. W. M. Smith, E. Herbst, J. Troe, W. Geppert, et al. Space Science Rev., 156, 13-72, 2010]. Our calculations for Titan's atmosphere demonstrate the importance of radiative emission as a stabilization process in the low-pressure environment of Titan's upper atmosphere. Theory has also helped to illuminate the role of various reactions in both Titan's atmosphere and in extrasolar planetary atmospheres. Comparisons between theory and experiment have provided a more detail understanding of the kinetics of PAH dimerization. High level predictions of thermochemical properties are remarkably accurate, and allow us to provide important data for studying P chemistry in planetary atmospheres. Finally, our study of O(3P) + C3 provides an example of a case where theory provides suggestive but not definitive results, and further experiments are clearly needed.