Science.gov

Sample records for temperature correction factor

  1. Impurity temperature correction factors for the transmission grating spectrometer in the TJ-II stellarator

    SciTech Connect

    Arevalo, J.; McCarthy, K. J.; Carmona, J. M.; Fontdecaba, J. M.

    2010-10-15

    Impurity ion temperature and velocity profiles are obtained across plasmas in the TJ-II stellarator by performing charge-exchange recombination spectroscopy with a diagnostic neutral beam injector. For this, a tridirectional (toroidal plus two poloidal opposing views) multichannel spectroscopic diagnostic, incorporating 12-way fiber arrays, a compact f/1.8 spectrograph, and a back-illuminated CCD, permits Doppler line shifts and widths (of the C VI line at 529.05 nm) to be determined with 1-2 cm spatial resolution. For good photon counting statistics under Li-coated wall conditions, 600 {mu}m diameter fibers collect and transmit light to curved 100 {mu}m wide input slits. When calibrated with a neon pencil lamp this entrance slit width results in a non-Gaussian instrumental function that, if not handled correctly, can result in systematically underestimated impurity temperatures. Here we develop and present correction factors for this effect for a range of conditions.

  2. Temperature Corrected Bootstrap Algorithm

    NASA Technical Reports Server (NTRS)

    Comiso, Joey C.; Zwally, H. Jay

    1997-01-01

    A temperature corrected Bootstrap Algorithm has been developed using Nimbus-7 Scanning Multichannel Microwave Radiometer data in preparation to the upcoming AMSR instrument aboard ADEOS and EOS-PM. The procedure first calculates the effective surface emissivity using emissivities of ice and water at 6 GHz and a mixing formulation that utilizes ice concentrations derived using the current Bootstrap algorithm but using brightness temperatures from 6 GHz and 37 GHz channels. These effective emissivities are then used to calculate surface ice which in turn are used to convert the 18 GHz and 37 GHz brightness temperatures to emissivities. Ice concentrations are then derived using the same technique as with the Bootstrap algorithm but using emissivities instead of brightness temperatures. The results show significant improvement in the area where ice temperature is expected to vary considerably such as near the continental areas in the Antarctic, where the ice temperature is colder than average, and in marginal ice zones.

  3. Determining the temporal variability in atmospheric temperature profiles measured using radiosondes and assessment of correction factors for different launch schedules

    NASA Astrophysics Data System (ADS)

    Butterfield, D.; Gardiner, T.

    2014-08-01

    Radiosondes provide one of the primary sources of upper atmosphere temperature data for numerical weather prediction, the assessment of long-term trends in atmospheric temperature, the study atmospheric processes and provide a source of intercomparison data for other temperature sensors e.g. satellites. When intercomparing different temperature profiles it is important to include the effect of temporal mis-match between the measurements. To help quantify this uncertainty the atmospheric temperature variation through the day needs to be assessed, so that a correction and uncertainty for time difference can be calculated. Temperature data from an intensive radiosonde campaign were analysed to calculate the hourly rate of change in temperature at different altitudes and provide recommendations and correction factors for different launch schedules. Using these results, three additional longer term data sets were analysed to assess the diurnal variability temperature as a function of altitude, time of day and season of the year. This provides data on the appropriate correction factors to use for a given temporal separation and the uncertainty associated with them. A general observation was that 10 or more repeat measurements would be required to get a standard uncertainty of less than 0.1 K h-1 of temporal mis-match.

  4. Determining the temporal variability in atmospheric temperature profiles measured using radiosondes and assessment of correction factors for different launch schedules

    NASA Astrophysics Data System (ADS)

    Butterfield, D.; Gardiner, T.

    2015-01-01

    Radiosondes provide one of the primary sources of upper troposphere and stratosphere temperature data for numerical weather prediction, the assessment of long-term trends in atmospheric temperature, study of atmospheric processes and provide intercomparison data for other temperature sensors, e.g. satellites. When intercomparing different temperature profiles it is important to include the effect of temporal mismatch between the measurements. To help quantify this uncertainty the atmospheric temperature variation through the day needs to be assessed, so that a correction and uncertainty for time difference can be calculated. Temperature data from an intensive radiosonde campaign, at Manus Island in Papua New Guinea, were analysed to calculate the hourly rate of change in temperature at different altitudes and provide recommendations and correction factors for different launch schedules. Using these results, three additional longer term data sets were analysed (Lindenberg 1999 to 2008; Lindenberg 2009 to 2012; and Southern Great Plains 2006 to 2012) to assess the diurnal variability of temperature as a function of altitude, time of day and season of the year. This provides the appropriate estimation of temperature differences for given temporal separation and the uncertainty associated with them. A general observation was that 10 or more repeat measurements would be required to get a standard error of the mean of less than 0.1 K per hour of temporal mismatch.

  5. An experimental and computational investigation of the standard temperature-pressure correction factor for ion chambers in kilovoltage x rays

    SciTech Connect

    La Russa, Daniel J.; McEwen, Malcolm; Rogers, D. W. O.

    2007-12-15

    For ion chambers with cavities open to the surrounding atmosphere, the response measured at a given temperature and pressure must be corrected using the standard temperature-pressure correction factor (P{sub TP}). A previous paper based solely on Monte Carlo simulations [D. J. La Russa and D. W. O. Rogers, Med. Phys. 33, 4590-4599 (2006)] pointed out the shortcomings of the P{sub TP} correction factor when used to correct the response of non-air-equivalent chambers for low-energy x-ray beams. This work presents the results of several experiments that corroborate these calculations for a number of ion chambers. Monte Carlo simulations of the experimental setup revealed additional insight into the various factors affecting the extent of the breakdown of P{sub TP}, including the effect of impurities and the sensitivity to chamber dimensions. For an unfiltered 60 kV beam, the P{sub TP}-corrected response of an NE 2571 ion chamber measured at 0.7 atm was 2.5% below the response measured at reference conditions. In general, Monte Carlo simulations of the experimental setup using EGSnrc were within 0.5% of measured values. EGSnrc-calculated values of air kerma calibration coefficients (N{sub K}) at low x-ray energies are also provided as a means of estimating the level of impurities in the chambers investigated. Calculated values of N{sub K} normalized to the value measured for a 250 kV beam were obtained for three chambers and were within 1% of experiment with one exception, the Exradin A12 in a 50 kV beam.

  6. Rectal temperature time of death nomogram: dependence of corrective factors on the body weight under stronger thermic insulation conditions.

    PubMed

    Henssge, C

    1992-04-01

    Ninety-eight test coolings were made under various cooling conditions (moving air, two types of both clothing and covering) on dummies of real masses of 1, 3.3, 9.9, 24.5 and 33.4 kg, respectively, which cool under standard conditions (unclothed, uncovered, still air) like human bodies of 14, 33, 41, 83 and 104 kg, respectively. The results provide evidence of a non-linear dependence of corrective factors of body weight upon the body weight. The dynamics of the dependence increases with the thickness of thermic insulation. Transferred to the use of the nomogram method on bodies, cooling conditions requiring corrective factors between 0.75 (moving air) and 1.3 (rather thin clothing/covering), known from experience on bodies of an average weight, can be used as in the past, independent of the body weight. According to experience the dependence of corrective factors on the body weight must be taken into account in bodies of a very high or low body weight. For that purpose both a simplified table and a formula for computing is given.

  7. Temperature Correction in Probe Measurements

    NASA Astrophysics Data System (ADS)

    Gutsev, S. A.

    2015-09-01

    This work is devoted to experimental investigations of a decaying plasma using Langmuir probes. The gas pressure, the discharge current, and the moment of afterglow were selected to obtain probe characteristics in collisionless, intermediate, and drifting regimes of motion of charged particles. The manner in which the shape of the volt- ampere characteristics changes on passage from the collisionless motion to diffusion motion has been shown. A detailed analysis has been made of the source of errors arising when orbital-motion formulas or the logarithmic-operation method are applied to processing of the probe curves. It has been shown that neglect of collisions of charged particles in the probe layer leads to an ion-density value overstated more than three times, an electron-temperature value overstated two times, and an ion temperature overstated three to nine times. A model of interaction of charged particles in the probe layer has been proposed for correction of the procedure of determining temperature. Such an approach makes it possible to determine the space-charge layer in the probe, and also the value of the self-consistent field. The use of the developed procedures gives good agreement between experimental and theoretical results.

  8. Temperature correction in conductivity measurements

    USGS Publications Warehouse

    Smith, Stanford H.

    1962-01-01

    Electrical conductivity has been widely used in freshwater research but usual methods employed by limnologists for converting measurements to conductance at a given temperature have not given uniformly accurate results. The temperature coefficient used to adjust conductivity of natural waters to a given temperature varies depending on the kinds and concentrations of electrolytes, the temperature at the time of measurement, and the temperature to which measurements are being adjusted. The temperature coefficient was found to differ for various lake and stream waters, and showed seasonal changes. High precision can be obtained only by determining temperature coefficients for each water studied. Mean temperature coefficients are given for various temperature ranges that may be used where less precision is required.

  9. Use supercompressibility as a meter correction factor

    SciTech Connect

    Nelson, M.B.

    1982-09-01

    Describes how, in the range of conditions experienced in the natural gas industry, the actual density of the gas volume measured is greater than the theoretical density related to Boyle's Law, and explains how the supercompressibility factor can correct this deviation. Northern States Power decided to apply supercompressibility as part of billing procedures after a study showed that if only customers with meter pressures of 20 psig and greater had the factor applied, 95.5% of the gas that is not being accounted for would be recovered. Supercompressibility as a function of gas composition, gas pressure, and temperature indicates the empirical relationship that relates the factor to the ideal gas laws. For normal compositions of natural gas, supercompressibility can be related to the gravity of the gas, taking into account mole fractions of CO/sub 2/ and N/sub 2/.

  10. Temperature-dependent spectral mismatch corrections

    DOE PAGESBeta

    Osterwald, Carl R.; Campanelli, Mark; Moriarty, Tom; Emery, Keith A.; Williams, Rafell

    2015-11-01

    This study develops the mathematical foundation for a translation of solar cell short-circuit current from one thermal and spectral irradiance operating condition to another without the use of ill-defined and error-prone temperature coefficients typically employed in solar cell metrology. Using the partial derivative of quantum efficiency with respect to temperature, the conventional isothermal expression for spectral mismatch corrections is modified to account for changes of current due to temperature; this modification completely eliminates the need for short-circuit-current temperature coefficients. An example calculation is provided to demonstrate use of the new translation.

  11. Factors of Addiction: New Jersey Correctional Population

    ERIC Educational Resources Information Center

    Wojtowicz, James P.; Liu, Tongyin; Hedgpeth, G. Wayne

    2007-01-01

    Most state inmates incarcerated under the jurisdiction of the New Jersey Department of Corrections are driven to crimes by drug abuse. Understanding the factors contributing to addiction is the first step in developing strategies for successful inmate reintegration. This study presents an analysis of inmate addiction and factor association using…

  12. FIELD CORRECTION FACTORS FOR PERSONAL NEUTRON DOSEMETERS.

    PubMed

    Luszik-Bhadra, M

    2016-09-01

    A field-dependent correction factor can be obtained by comparing the readings of two albedo neutron dosemeters fixed in opposite directions on a polyethylene sphere to the H*(10) reading as determined with a thermal neutron detector in the centre of the same sphere. The work shows that the field calibration technique as used for albedo neutron dosemeters can be generalised for all kind of dosemeters, since H*(10) is a conservative estimate of the sum of the personal dose equivalents Hp(10) in two opposite directions. This result is drawn from reference values as determined by spectrometers within the EVIDOS project at workplace of nuclear installations in Europe. More accurate field-dependent correction factors can be achieved by the analysis of several personal dosimeters on a phantom, but reliable angular responses of these dosemeters need to be taken into account. PMID:26493946

  13. Fermilab's Booster Correction Element Power Supply Silicon Temperature Rise

    SciTech Connect

    Krafczyk, G.; Jensen, C.; Pfeffer, H.; Warchol, G.; /Fermilab

    2009-05-01

    Fermilab is in the process of upgrading its Booster Correction Element System to include full field correction element magnets to correct position and chromaticity throughout the booster cycle. For good reliability of the switchmode power supplies designed to power the magnets, it is important to limit both the maximum temperature and the repetitive temperature cycling of the silicon junctions of the switching elements. We will describe how we measured these parameters and the results of our measurements.

  14. Correction factors for assessing immersion suits under harsh conditions.

    PubMed

    Power, Jonathan; Tikuisis, Peter; Ré, António Simões; Barwood, Martin; Tipton, Michael

    2016-03-01

    Many immersion suit standards require testing of thermal protective properties in calm, circulating water while these suits are typically used in harsher environments where they often underperform. Yet it can be expensive and logistically challenging to test immersion suits in realistic conditions. The goal of this work was to develop a set of correction factors that would allow suits to be tested in calm water yet ensure they will offer sufficient protection in harsher conditions. Two immersion studies, one dry and the other with 500 mL of water within the suit, were conducted in wind and waves to measure the change in suit insulation. In both studies, wind and waves resulted in a significantly lower immersed insulation value compared to calm water. The minimum required thermal insulation for maintaining heat balance can be calculated for a given mean skin temperature, metabolic heat production, and water temperature. Combining the physiological limits of sustainable cold water immersion and actual suit insulation, correction factors can be deduced for harsh conditions compared to calm. The minimum in-situ suit insulation to maintain thermal balance is 1.553-0.0624·TW + 0.00018·TW(2) for a dry calm condition. Multiplicative correction factors to the above equation are 1.37, 1.25, and 1.72 for wind + waves, 500 mL suit wetness, and both combined, respectively. Calm water certification tests of suit insulation should meet or exceed the minimum in-situ requirements to maintain thermal balance, and correction factors should be applied for a more realistic determination of minimum insulation for harsh conditions. PMID:26674408

  15. Correction factors for assessing immersion suits under harsh conditions.

    PubMed

    Power, Jonathan; Tikuisis, Peter; Ré, António Simões; Barwood, Martin; Tipton, Michael

    2016-03-01

    Many immersion suit standards require testing of thermal protective properties in calm, circulating water while these suits are typically used in harsher environments where they often underperform. Yet it can be expensive and logistically challenging to test immersion suits in realistic conditions. The goal of this work was to develop a set of correction factors that would allow suits to be tested in calm water yet ensure they will offer sufficient protection in harsher conditions. Two immersion studies, one dry and the other with 500 mL of water within the suit, were conducted in wind and waves to measure the change in suit insulation. In both studies, wind and waves resulted in a significantly lower immersed insulation value compared to calm water. The minimum required thermal insulation for maintaining heat balance can be calculated for a given mean skin temperature, metabolic heat production, and water temperature. Combining the physiological limits of sustainable cold water immersion and actual suit insulation, correction factors can be deduced for harsh conditions compared to calm. The minimum in-situ suit insulation to maintain thermal balance is 1.553-0.0624·TW + 0.00018·TW(2) for a dry calm condition. Multiplicative correction factors to the above equation are 1.37, 1.25, and 1.72 for wind + waves, 500 mL suit wetness, and both combined, respectively. Calm water certification tests of suit insulation should meet or exceed the minimum in-situ requirements to maintain thermal balance, and correction factors should be applied for a more realistic determination of minimum insulation for harsh conditions.

  16. Corrected Hawking Temperature in Snyder's Quantized Space-time

    NASA Astrophysics Data System (ADS)

    Ma, Meng-Sen; Liu, Fang; Zhao, Ren

    2015-06-01

    In the quantized space-time of Snyder, generalized uncertainty relation and commutativity are both included. In this paper we analyze the possible form for the corrected Hawking temperature and derive it from the both effects. It is shown that the corrected Hawking temperature has a form similar to the one of noncommutative geometry inspired Schwarzschild black hole, however with an requirement for the noncommutative parameter 𝜃 and the minimal length a.

  17. Temperature-Corrected Model of Turbulence in Hot Jet Flows

    NASA Technical Reports Server (NTRS)

    Abdol-Hamid, Khaled S.; Pao, S. Paul; Massey, Steven J.; Elmiligui, Alaa

    2007-01-01

    An improved correction has been developed to increase the accuracy with which certain formulations of computational fluid dynamics predict mixing in shear layers of hot jet flows. The CFD formulations in question are those derived from the Reynolds-averaged Navier-Stokes equations closed by means of a two-equation model of turbulence, known as the k-epsilon model, wherein effects of turbulence are summarized by means of an eddy viscosity. The need for a correction arises because it is well known among specialists in CFD that two-equation turbulence models, which were developed and calibrated for room-temperature, low Mach-number, plane-mixing-layer flows, underpredict mixing in shear layers of hot jet flows. The present correction represents an attempt to account for increased mixing that takes place in jet flows characterized by high gradients of total temperature. This correction also incorporates a commonly accepted, previously developed correction for the effect of compressibility on mixing.

  18. An Accurate Temperature Correction Model for Thermocouple Hygrometers 1

    PubMed Central

    Savage, Michael J.; Cass, Alfred; de Jager, James M.

    1982-01-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques. In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38°C). The model based on calibration at two temperatures is superior to that based on only one calibration. The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25°C, if the calibration slopes are corrected for temperature. PMID:16662241

  19. An accurate temperature correction model for thermocouple hygrometers.

    PubMed

    Savage, M J; Cass, A; de Jager, J M

    1982-02-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques.In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38 degrees C). The model based on calibration at two temperatures is superior to that based on only one calibration.The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25 degrees C, if the calibration slopes are corrected for temperature.

  20. An accurate temperature correction model for thermocouple hygrometers.

    PubMed

    Savage, M J; Cass, A; de Jager, J M

    1982-02-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques.In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38 degrees C). The model based on calibration at two temperatures is superior to that based on only one calibration.The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25 degrees C, if the calibration slopes are corrected for temperature. PMID:16662241

  1. Calibration and temperature correction of heat dissipation matric potential sensors

    USGS Publications Warehouse

    Flint, A.L.; Campbell, G.S.; Ellett, K.M.; Calissendorff, C.

    2002-01-01

    This paper describes how heat dissipation sensors, used to measure soil water matric potential, were analyzed to develop a normalized calibration equation and a temperature correction method. Inference of soil matric potential depends on a correlation between the variable thermal conductance of the sensor's porous ceramic and matric poten-tial. Although this correlation varies among sensors, we demonstrate a normalizing procedure that produces a single calibration relationship. Using sensors from three sources and different calibration methods, the normalized calibration resulted in a mean absolute error of 23% over a matric potential range of -0.01 to -35 MPa. Because the thermal conductivity of variably saturated porous media is temperature dependent, a temperature correction is required for application of heat dissipation sensors in field soils. A temperature correction procedure is outlined that reduces temperature dependent errors by 10 times, which reduces the matric potential measurement errors by more than 30%. The temperature dependence is well described by a thermal conductivity model that allows for the correction of measurements at any temperature to measurements at the calibration temperature.

  2. Reflection error correction of gas turbine blade temperature

    NASA Astrophysics Data System (ADS)

    Kipngetich, Ketui Daniel; Feng, Chi; Gao, Shan

    2016-03-01

    Accurate measurement of gas turbine blades' temperature is one of the greatest challenges encountered in gas turbine temperature measurements. Within an enclosed gas turbine environment with surfaces of varying temperature and low emissivities, a new challenge is introduced into the use of radiation thermometers due to the problem of reflection error. A method for correcting this error has been proposed and demonstrated in this work through computer simulation and experiment. The method assumed that emissivities of all surfaces exchanging thermal radiation are known. Simulations were carried out considering targets with low and high emissivities of 0.3 and 0.8 respectively while experimental measurements were carried out on blades with emissivity of 0.76. Simulated results showed possibility of achieving error less than 1% while experimental result corrected the error to 1.1%. It was thus concluded that the method is appropriate for correcting reflection error commonly encountered in temperature measurement of gas turbine blades.

  3. Finite temperature corrections in 2d integrable models

    NASA Astrophysics Data System (ADS)

    Caselle, M.; Hasenbusch, M.

    2002-09-01

    We study the finite size corrections for the magnetization and the internal energy of the 2d Ising model in a magnetic field by using transfer matrix techniques. We compare these corrections with the functional form recently proposed by Delfino and LeClair-Mussardo for the finite temperature behaviour of one-point functions in integrable 2d quantum field theories. We find a perfect agreement between theoretical expectations and numerical results. Assuming the proposed functional form as an input in our analysis we obtain a relevant improvement in the precision of the continuum limit estimates of both quantities.

  4. Correction of Temperatures of Air-Cooled Engine Cylinders for Variation in Engine and Cooling Conditions

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Pinkel, Benjamin; Ellerbrock, Herman H , Jr

    1939-01-01

    Factors are obtained from semiempirical equations for correcting engine-cylinder temperatures for variation in important engine and cooling conditions. The variation of engine temperatures with atmospheric temperature is treated in detail, and correction factors are obtained for various flight and test conditions, such as climb at constant indicated air speed, level flight, ground running, take-off, constant speed of cooling air, and constant mass flow of cooling air. Seven conventional air-cooled engine cylinders enclosed in jackets and cooled by a blower were tested to determine the effect of cooling-air temperature and carburetor-air temperature on cylinder temperatures. The cooling air temperature was varied from approximately 80 degrees F. to 230 degrees F. and the carburetor-air temperature from approximately 40 degrees F. to 160 degrees F. Tests were made over a large range of engine speeds, brake mean effective pressures, and pressure drops across the cylinder. The correction factors obtained experimentally are compared with those obtained from the semiempirical equations and a fair agreement is noted.

  5. Journal Impact Factor: Do the Numerator and Denominator Need Correction?

    PubMed

    Liu, Xue-Li; Gai, Shuang-Shuang; Zhou, Jing

    2016-01-01

    To correct the incongruence of document types between the numerator and denominator in the traditional impact factor (IF), we make a corresponding adjustment to its formula and present five corrective IFs: IFTotal/Total, IFTotal/AREL, IFAR/AR, IFAREL/AR, and IFAREL/AREL. Based on a survey of researchers in the fields of ophthalmology and mathematics, we obtained the real impact ranking of sample journals in the minds of peer experts. The correlations between various IFs and questionnaire score were analyzed to verify their journal evaluation effects. The results show that it is scientific and reasonable to use five corrective IFs for journal evaluation for both ophthalmology and mathematics. For ophthalmology, the journal evaluation effects of the five corrective IFs are superior than those of traditional IF: the corrective effect of IFAR/AR is the best, IFAREL/AR is better than IFTotal/Total, followed by IFTotal/AREL, and IFAREL/AREL. For mathematics, the journal evaluation effect of traditional IF is superior than those of the five corrective IFs: the corrective effect of IFTotal/Total is best, IFAREL/AR is better than IFTotal/AREL and IFAREL/AREL, and the corrective effect of IFAR/AR is the worst. In conclusion, not all disciplinary journal IF need correction. The results in the current paper show that to correct the IF of ophthalmologic journals may be valuable, but it seems to be meaningless for mathematic journals.

  6. Journal Impact Factor: Do the Numerator and Denominator Need Correction?

    PubMed Central

    Liu, Xue-Li; Gai, Shuang-Shuang; Zhou, Jing

    2016-01-01

    To correct the incongruence of document types between the numerator and denominator in the traditional impact factor (IF), we make a corresponding adjustment to its formula and present five corrective IFs: IFTotal/Total, IFTotal/AREL, IFAR/AR, IFAREL/AR, and IFAREL/AREL. Based on a survey of researchers in the fields of ophthalmology and mathematics, we obtained the real impact ranking of sample journals in the minds of peer experts. The correlations between various IFs and questionnaire score were analyzed to verify their journal evaluation effects. The results show that it is scientific and reasonable to use five corrective IFs for journal evaluation for both ophthalmology and mathematics. For ophthalmology, the journal evaluation effects of the five corrective IFs are superior than those of traditional IF: the corrective effect of IFAR/AR is the best, IFAREL/AR is better than IFTotal/Total, followed by IFTotal/AREL, and IFAREL/AREL. For mathematics, the journal evaluation effect of traditional IF is superior than those of the five corrective IFs: the corrective effect of IFTotal/Total is best, IFAREL/AR is better than IFTotal/AREL and IFAREL/AREL, and the corrective effect of IFAR/AR is the worst. In conclusion, not all disciplinary journal IF need correction. The results in the current paper show that to correct the IF of ophthalmologic journals may be valuable, but it seems to be meaningless for mathematic journals. PMID:26977697

  7. Weighing system for vehicles with temperature and inclinometer correction

    SciTech Connect

    Bambauer, B.R.; Dunkle, D.H.; Loscutoff, S.

    1986-11-18

    This patent describes for use in conjunction with a vehicle having a frame and a plurality of axles wherein each axle has a pair of springs, an improved weighing system comprising: a pair of enclosed cylinder means mounted on each of the axles adjacent the springs and connected to the frame; each of the enclosed cylinder means comprising two telescoping support tubes which slide vertically with respect to each other as the frame moves vertically with respect to the axles; ultrasonic transducer means mounted inside one end of the enclosed cylinder means; ultrasonic reflector means mounted inside the other end of the enclosed cylinder means; temperature sensing means mounted inside the cylinder means; and circuit means for sequentially sensing the displacement of each of the transducer means relative to its corresponding reflector means, correcting for temperatures sensed in each of enclosed cylinder means, and integrating the displacement signals to correct for any inclined terrain on which the tractor-trailer stands when weighed.

  8. Radiative corrections to the Casimir effect at nonzero temperatures

    SciTech Connect

    Wieczorek, E.; Robaschik, D.; Scharnhorst, K.

    1986-10-01

    Quantum electrodynamics at nonzero temperatures with boundary conditions is formulated on the basis of the functional integral using the results of previous studies (Sov. J. Nucl. Phys. 39, 663 (1984); Ann. Phys. (N.Y.) 165, 192 (1985)). The Matsubara imaginary-time formalism and the thermal field approach of perturbation theory are used. The loop corrections to the free-energy functional are calculated in a physically reasonable limit.

  9. Eucken correction in high-temperature gases with electronic excitation

    SciTech Connect

    Istomin, V. A.; Kustova, E. V. Mekhonoshina, M. A.

    2014-05-14

    In the present paper, thermal conductivity coefficient of high-temperature molecular and atomic gases with excited electronic states is studied using both the kinetic theory algorithm developed by authors earlier and the well known simple expression for the thermal conductivity coefficient proposed by Eucken and generalized by Hirschfelder. The influence of large collision diameters of excited states on the thermal conductivity is discussed. The limit of validity of the Eucken correction is evaluated on the basis of the kinetic theory calculations; an improved model suitable for air species under high-temperature conditions is proposed.

  10. Quantum Mechanical Corrections to Simulated Shock Hugoniot Temperatures

    SciTech Connect

    Goldman, N; Reed, E; Fried, L E

    2009-07-17

    The authors present a straightforward method for the inclusion of quantum nuclear vibrational effects in molecular dynamics calculations of shock Hugoniot temperatures. Using a grueneisen equation of state and a quasi-harmonic approximation to the vibrational energies, they derive a simple, post-processing method for calculation of the quantum corrected Hugoniot temperatures. They have used our novel technique on ab initio simulations of both shock compressed water and methane. Our results indicate significantly closer agreement with all available experimental temperature data for these two systems. Our formalism and technique can be easily applied to a number of different shock compressed molecular liquids or covalent solids, and has the potential to decrease the large uncertainties inherent in many experimental Hugoniot temperature measurements of these systems.

  11. Differences between EPA-test and in-use fuel economy: Are the correction factors correct

    SciTech Connect

    Mintz, M.M.; Vyas, A.R.D.; Conley, L.A.

    1993-01-01

    A vehicle's in-use or on-the-road fuel economy often differs substantially from the miles-per-gallon estimates developed by the US Environmental Protection Agency (EPA) as part of its emissions certification program. As a result, the certification values are routinely adjusted by a set of correction factors so that the resulting estimates will better reflect in-use experience. Using data from the Residential Transportation Energy Consumption Survey conducted by the Energy Information Administration of the US Department of Energy, our analysis investigated how well the correction factors replicated the shortfall experience of all household vehicles on the road in 1985. Results show that the shortfall is larger than the EPA correction factors, and light trucks are experiencing significantly larger shortfalls than automobiles.

  12. Differences between EPA-test and in-use fuel economy: Are the correction factors correct?

    SciTech Connect

    Mintz, M.M.; Vyas, A.R.D.; Conley, L.A.

    1993-02-01

    A vehicle`s in-use or on-the-road fuel economy often differs substantially from the miles-per-gallon estimates developed by the US Environmental Protection Agency (EPA) as part of its emissions certification program. As a result, the certification values are routinely adjusted by a set of correction factors so that the resulting estimates will better reflect in-use experience. Using data from the Residential Transportation Energy Consumption Survey conducted by the Energy Information Administration of the US Department of Energy, our analysis investigated how well the correction factors replicated the shortfall experience of all household vehicles on the road in 1985. Results show that the shortfall is larger than the EPA correction factors, and light trucks are experiencing significantly larger shortfalls than automobiles.

  13. Temperature Correction of Pressure-Sensitive Paints Simplified

    NASA Technical Reports Server (NTRS)

    Bencic, Timothy J.

    2000-01-01

    Pressure-sensitive paint (PSP) has become a useful tool to augment conventional pressure taps in measuring the surface pressure distribution of aerodynamic components in wind tunnel testing. Although PSP offers the advantage of nonintrusive global mapping of the surface pressure, one prominent drawback to the accuracy of this technique is the inherent temperature sensitivity of PSP's luminescent intensity. Typical aerodynamic surface PSP tests rely on the coated surface to be both spatially and temporally isothermal, along with conventional instrumentation, to yield the highest accuracy pressure mappings. In some tests, however, spatial and temporal thermal gradients are generated by the nature of the test, as in a blowing jet impinging on a surface. In these cases, high accuracy and reliable data cannot be obtained unless the temperature variations on the painted surface are accounted for. A new temperature-correction technique was developed at the NASA Glenn Research Center at Lewis Field to collapse a "family" of PSP calibration curves to a single curve of intensity ratio versus pressure. This correction allows a streamlined procedure to be followed whether or not temperature information is used in the data reduction of the PSP.

  14. Semiclassical zero-temperature corrections to Schwarzschild spacetime and holography

    SciTech Connect

    Fabbri, A.; Farese, S.; Navarro-Salas, J.; Sanchis-Alepuz, H.; Olmo, G.J.

    2006-05-15

    Motivated by the quest for black holes in anti-de Sitter braneworlds, and, in particular, by the holographic conjecture relating 5D classical bulk solutions with 4D quantum corrected ones, we numerically solve the semiclassical Einstein equations (backreaction equations) with matter fields in the (zero-temperature) Boulware vacuum state. In the absence of an exact analytical expression for in four dimensions we work within the s-wave approximation. Our results show that the quantum corrected solution is very similar to Schwarzschild spacetime until very close to the horizon, but then a bouncing surface for the radial function appears which prevents the formation of an event horizon. We also analyze the behavior of the geometry beyond the bounce, where a curvature singularity arises. In the dual theory, this indicates that the corresponding 5D static classical braneworld solution is not a black hole but rather a naked singularity.

  15. Exchange corrections in a low-temperature plasma.

    PubMed

    Ekman, Robin; Zamanian, Jens; Brodin, Gert

    2015-07-01

    We have studied the exchange corrections to linear electrostatic wave propagation in a plasma using a quantum kinetic formalism. Specifically, we have considered the zero-temperature limit. In order to simplify the calculations we have focused on the long-wavelength limit, i.e., wavelengths much longer than the de Broglie wavelength. For the case of ion-acoustic waves we have calculated the exchange correction both to the damping rate and the real part of the frequency. For Langmuir waves the frequency shift due to exchange effects is found. Our results are compared with the frequency shifts deduced from commonly used exchange potentials which are computed from density-functional theory. PMID:26274291

  16. An EGSnrc investigation of correction factors for ion chamber dosimetry

    NASA Astrophysics Data System (ADS)

    Buckley, Lesley A.

    Radiation dosimetry is used to quantify the dose delivered during radiation therapy by using ionization chambers with several correction factors. Knowledge of these factors is needed at well below the 1% level in order to maintain the overall uncertainty on the reference dosimetry near 1-2%. The small magnitude of the corrections renders measurements very difficult. Monte Carlo calculations are widely used for this purpose, however they require very low statistical uncertainties. A new user-code, CSnrc, for the EGSnrc Monte Carlo system is described. CSnrc uses a correlated sampling variance reduction technique to reduce the uncertainty for dose ratio calculations. Compared to an existing EGSnrc user-code from which it was developed, CSnrc shows gains in efficiency of up to a factor of 64 and achieves much lower statistical uncertainties on correction factors than previously published. CSnrc is used to compute the central electrode correction factor, Pcel, in a broader range of beams than previously used and at the depths relevant to modern protocols. For photon beams, the CSnrc values compare well with the values used in dosimetry protocols whereas for electron beams, CSnrc shows up to a 0.2% correction for a graphite electrode, a correction currently ignored by dosimetry protocols. The difference from currently used values is slightly less for an aluminum electrode. CSnrc is also used to compute the wall correction factor, P wall. For cylindrical chambers in photon beams, the CSnrc calculations are compared to the currently used Almond-Svensson formalism and differ from this formalism by as much as 0.8%. The CSnrc values are used to explain some previously published experiments showing problems with Pwall . For electron beams, where dosimetry protocols assume a Pwall of unity, CSnrc calculations show a correction as large as 0.6%. For parallel-plate chambers, there is little information available regarding Pwall in photon beams. CSnrc shows corrections of over 2

  17. 49 CFR 325.79 - Application of correction factors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Application of correction factors. 325.79 Section 325.79 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH INTERSTATE...

  18. 49 CFR 325.79 - Application of correction factors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Application of correction factors. 325.79 Section 325.79 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH INTERSTATE...

  19. 49 CFR 325.79 - Application of correction factors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Application of correction factors. 325.79 Section 325.79 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH INTERSTATE...

  20. 49 CFR 325.73 - Microphone distance correction factors. 1

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Microphone distance correction factors. 1 325.73 Section 325.73 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  1. 49 CFR 325.73 - Microphone distance correction factors. 1

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Microphone distance correction factors. 1 325.73 Section 325.73 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  2. 49 CFR 325.79 - Application of correction factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Application of correction factors. 325.79 Section 325.79 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH INTERSTATE...

  3. 49 CFR 325.73 - Microphone distance correction factors. 1

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Microphone distance correction factors. 1 325.73 Section 325.73 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  4. 49 CFR 325.75 - Ground surface correction factors. 1

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Ground surface correction factors. 1 325.75 Section 325.75 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  5. 49 CFR 325.79 - Application of correction factors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Application of correction factors. 325.79 Section 325.79 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH INTERSTATE...

  6. 49 CFR 325.75 - Ground surface correction factors. 1

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Ground surface correction factors. 1 325.75 Section 325.75 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  7. 49 CFR 325.75 - Ground surface correction factors. 1

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Ground surface correction factors. 1 325.75 Section 325.75 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  8. 49 CFR 325.73 - Microphone distance correction factors. 1

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Microphone distance correction factors. 1 325.73 Section 325.73 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  9. 49 CFR 325.75 - Ground surface correction factors. 1

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Ground surface correction factors. 1 325.75 Section 325.75 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  10. 49 CFR 325.73 - Microphone distance correction factors. 1

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Microphone distance correction factors. 1 325.73 Section 325.73 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...

  11. 49 CFR 325.75 - Ground surface correction factors. 1

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... determine whether the motor vehicle conforms to the Standards for Highway Operations, 40 CFR 202.20. (b... the motor vehicle conforms to the Standard for Operation Under Stationary Test, 40 CFR 202.21. ... 49 Transportation 5 2010-10-01 2010-10-01 false Ground surface correction factors. 1...

  12. Finite-temperature corrections in the dilated chiral quark model

    SciTech Connect

    Kim, Y.; Lee, Hyun Kyu |; Rho, M. |

    1995-03-01

    We calculate the finite-temperature corrections in the dilated chiral quark model using the effective potential formalism. Assuming that the dilaton limit is applicable at some short length scale, we interpret the results to represent the behavior of hadrons in dense and hot matter. We obtain the scaling law, f{sub {pi}}(T)/f{sub {pi}} = m{sub Q}(T)/m{sub Q} {approx_equal} m{sub {sigma}}(T)/m{sub {sigma}}while we argue, using PCAC, that pion mass does not scale within the temperature range involved in our Lagrangian. It is found that the hadron masses and the pion decay constant drop faster with temperature in the dilated chiral quark model than in the conventional linear sigma model that does not take into account the QCD scale anomaly. We attribute the difference in scaling in heat bath to the effect of baryonic medium on thermal properties of the hadrons. Our finding would imply that the AGS experiments (dense and hot matter) and the RHIC experiments (hot and dilute matter) will ``see`` different hadron properties in the hadronization exit phase.

  13. Amplitude Correction Factors of Korean VLBI Network Observations

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Sung; Byun, Do-Young; Oh, Chung Sik; Kim, Hyo Ryoung; Kim, Jongsoo; Jung, Taehyun; Oh, Se-Jin; Roh, Duk-Gyoo; Jung, Dong-Kyu; Yeom, Jae-Hwan

    2015-10-01

    We report results of investigation of amplitude calibration for very long baseline interferometry (VLBI) observations with Korean VLBI Network (KVN). Amplitude correction factors are estimated based on comparison of KVN observations at 22~GHz correlated by Daejeon hardware correlator and DiFX software correlator in Korea Astronomy and Space Science Institute (KASI) with Very Long Baseline Array (VLBA) observations at 22~GHz by DiFX software correlator in National Radio Astronomy Observatory (NRAO). We used the observations for compact radio sources, 3C~454.3, NRAO~512, OJ 287, BL Lac, 3C 279, 1633+382, and 1510-089, which are almost unresolved for baselines in a range of 350-477~km. Visibility data of the sources obtained with similar baselines at KVN and VLBA are selected, fringe-fitted, calibrated, and compared for their amplitudes. We find that visibility amplitudes of KVN observations should be corrected by factors of 1.10 and 1.35 when correlated by DiFX and Daejeon correlators, respectively. These correction factors are attributed to the combination of two steps of 2-bit quantization in KVN observing systems and characteristics of Daejeon correlator.

  14. The Etiology of Presbyopia, Contributing Factors, and Future Correction Methods

    NASA Astrophysics Data System (ADS)

    Hickenbotham, Adam Lyle

    Presbyopia has been a complicated problem for clinicians and researchers for centuries. Defining what constitutes presbyopia and what are its primary causes has long been a struggle for the vision and scientific community. Although presbyopia is a normal aging process of the eye, the continuous and gradual loss of accommodation is often dreaded and feared. If presbyopia were to be considered a disease, its global burden would be enormous as it affects more than a billion people worldwide. In this dissertation, I explore factors associated with presbyopia and develop a model for explaining the onset of presbyopia. In this model, the onset of presbyopia is associated primarily with three factors; depth of focus, focusing ability (accommodation), and habitual reading (or task) distance. If any of these three factors could be altered sufficiently, the onset of presbyopia could be delayed or prevented. Based on this model, I then examine possible optical methods that would be effective in correcting for presbyopia by expanding depth of focus. Two methods that have been show to be effective at expanding depth of focus include utilizing a small pupil aperture or generating higher order aberrations, particularly spherical aberration. I compare these two optical methods through the use of simulated designs, monitor testing, and visual performance metrics and then apply them in subjects through an adaptive optics system that corrects aberrations through a wavefront aberrometer and deformable mirror. I then summarize my findings and speculate about the future of presbyopia correction.

  15. Finite-temperature electron correlations in the framework of a dynamic local-field correction

    SciTech Connect

    Schweng, H.K.; Boehm, H.M. )

    1993-07-15

    The quantum-mechanical version of the Singwi-Tosi-Land-Sjoelander (STLS) approximation is applied to finite temperatures. This approximation has two main advantages. First, it includes a dynamic local-field correction and second, it gives positive values for the pair-distribution function in the short-range region at zero temperature. This is even valid for rather low densities. After a description of the numerical difficulties arising with the use of a dynamic approximation, the results for the static-structure factor and the pair-distribution function are discussed thoroughly. Detailed work is performed on the static part of the local-field correction, with special emphasis put on the investigation of its structure. A peak is found at a wave vector [ital q][approx]2.8 (in units of the Fermi wave vector) for small temperatures, which tends towards higher values of [ital q] with increasing temperature. This peak causes an attractive particle-hole interaction in a certain [ital q] region and thus gives rise to the appearance of a charge-density wave. A parametric description is given for the static local-field correction in order to simplify further applications. Furthermore, the exchange-and-correlation free energy is considered. The results are compared with the STLS results and with the modified convolution approach.

  16. Air-braked cycle ergometers: validity of the correction factor for barometric pressure.

    PubMed

    Finn, J P; Maxwell, B F; Withers, R T

    2000-10-01

    Barometric pressure exerts by far the greatest influence of the three environmental factors (barometric pressure, temperature and humidity) on power outputs from air-braked ergometers. The barometric pressure correction factor for power outputs from air-braked ergometers is in widespread use but apparently has never been empirically validated. Our experiment validated this correction factor by calibrating two air-braked cycle ergometers in a hypobaric chamber using a dynamic calibration rig. The results showed that if the power output correction for changes in air resistance at barometric pressures corresponding to altitudes of 38, 600, 1,200 and 1,800 m above mean sea level were applied, then the coefficients of variation were 0.8-1.9% over the range of 160-1,597 W. The overall mean error was 3.0 % but this included up to 0.73 % for the propagated error that was associated with errors in the measurement of: a) temperature b) relative humidity c) barometric pressure d) force, distance and angular velocity by the dynamic calibration rig. The overall mean error therefore approximated the +/- 2.0% of true load that was specified by the Laboratory Standards Assistance Scheme of the Australian Sports Commission. The validity of the correction factor for barometric pressure on power output was therefore demonstrated over the altitude range of 38-1,800 m.

  17. Air-braked cycle ergometers: validity of the correction factor for barometric pressure.

    PubMed

    Finn, J P; Maxwell, B F; Withers, R T

    2000-10-01

    Barometric pressure exerts by far the greatest influence of the three environmental factors (barometric pressure, temperature and humidity) on power outputs from air-braked ergometers. The barometric pressure correction factor for power outputs from air-braked ergometers is in widespread use but apparently has never been empirically validated. Our experiment validated this correction factor by calibrating two air-braked cycle ergometers in a hypobaric chamber using a dynamic calibration rig. The results showed that if the power output correction for changes in air resistance at barometric pressures corresponding to altitudes of 38, 600, 1,200 and 1,800 m above mean sea level were applied, then the coefficients of variation were 0.8-1.9% over the range of 160-1,597 W. The overall mean error was 3.0 % but this included up to 0.73 % for the propagated error that was associated with errors in the measurement of: a) temperature b) relative humidity c) barometric pressure d) force, distance and angular velocity by the dynamic calibration rig. The overall mean error therefore approximated the +/- 2.0% of true load that was specified by the Laboratory Standards Assistance Scheme of the Australian Sports Commission. The validity of the correction factor for barometric pressure on power output was therefore demonstrated over the altitude range of 38-1,800 m. PMID:11071051

  18. Environmental correction factors for predicting room sound pressure levels

    SciTech Connect

    Warnock, A.C.C.

    1998-10-01

    ARI Standard 885 provides a method for calculating sound pressure levels in room below plenums containing air-handling devices. An important step in the calculation is the correction of the sound power for the device from values provided by the manufacturer to values appropriate for use in occupied spaces. This correction is called the environmental adjustment factor. It compensates for the fact that sound power measured for a source placed outdoors or in a hemi-free field has been found to be greater at low frequencies than the sound power measured for the same source in a reverberation room. When making predictions of sound pressure level in a room using such sound power levels, one has to estimate the reduction in sound power caused by the room. Estimated reductions provided in ARI 885 were examined during ASHRAE research project RP-755 and found to be too large. Lower values are suggested in this paper.

  19. Correction factors for gravimetric measurement of peritumoural oedema in man.

    PubMed

    Bell, B A; Smith, M A; Tocher, J L; Miller, J D

    1987-01-01

    The water content of samples of normal and oedematous brain in lobectomy specimens from 16 patients with cerebral tumours has been measured by gravimetry and by wet and dry weighing. Uncorrected gravimetry underestimated the water content of oedematous peritumoural cortex by a mean of 1.17%, and of oedematous peritumoural white matter by a mean of 2.52%. Gravimetric correction equations calculated theoretically and from an animal model of serum infusion white matter oedema overestimate peritumoural white matter oedema in man, and empirical gravimetric error correction factors for oedematous peritumoural human white matter and cortex have therefore been derived. These enable gravimetry to be used to accurately determine peritumoural oedema in man. PMID:3268140

  20. Correction factors for gravimetric measurement of peritumoural oedema in man.

    PubMed

    Bell, B A; Smith, M A; Tocher, J L; Miller, J D

    1987-01-01

    The water content of samples of normal and oedematous brain in lobectomy specimens from 16 patients with cerebral tumours has been measured by gravimetry and by wet and dry weighing. Uncorrected gravimetry underestimated the water content of oedematous peritumoural cortex by a mean of 1.17%, and of oedematous peritumoural white matter by a mean of 2.52%. Gravimetric correction equations calculated theoretically and from an animal model of serum infusion white matter oedema overestimate peritumoural white matter oedema in man, and empirical gravimetric error correction factors for oedematous peritumoural human white matter and cortex have therefore been derived. These enable gravimetry to be used to accurately determine peritumoural oedema in man.

  1. Experimental and casework validation of ambient temperature corrections in forensic entomology.

    PubMed

    Johnson, Aidan P; Wallman, James F; Archer, Melanie S

    2012-01-01

    This paper expands on Archer (J Forensic Sci 49, 2004, 553), examining additional factors affecting ambient temperature correction of weather station data in forensic entomology. Sixteen hypothetical body discovery sites (BDSs) in Victoria and New South Wales (Australia), both in autumn and in summer, were compared to test whether the accuracy of correlation was affected by (i) length of correlation period; (ii) distance between BDS and weather station; and (iii) periodicity of ambient temperature measurements. The accuracy of correlations in data sets from real Victorian and NSW forensic entomology cases was also examined. Correlations increased weather data accuracy in all experiments, but significant differences in accuracy were found only between periodicity treatments. We found that a >5°C difference between average values of body in situ and correlation period weather station data was predictive of correlations that decreased the accuracy of ambient temperatures estimated using correlation. Practitioners should inspect their weather data sets for such differences.

  2. A temperature error correction method for a naturally ventilated radiation shield

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Liu, Qingquan; Dai, Wei; Ding, Rrenhui

    2016-11-01

    Due to solar radiation exposure, air flowing inside a naturally ventilated radiation shield may produce a measurement error of 0.8 °C or higher. To improve the air temperature observation accuracy, a temperature error correction method is proposed. The correction method is based on a Computational Fluid Dynamics (CFD) method and a Genetic Algorithm (GA) method. The CFD method is implemented to analyze and calculate the temperature errors of a naturally ventilated radiation shield under various environmental conditions. Then, a temperature error correction equation is obtained by fitting the CFD results using the GA method. To verify the performance of the correction equation, the naturally ventilated radiation shield and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated temperature measurement platform serves as an air temperature reference. The mean temperature error given by measurements is 0.36 °C, and the mean temperature error given by correction equation is 0.34 °C. This correction equation allows the temperature error to be reduced by approximately 95%. The mean absolute error (MAE) and the root mean square error (RMSE) between the temperature errors given by the correction equation and the temperature errors given by the measurements are 0.07 °C and 0.08 °C, respectively.

  3. Adaptive non-uniformity correction method based on temperature for infrared detector array

    NASA Astrophysics Data System (ADS)

    Zhang, Zhijie; Yue, Song; Hong, Pu; Jia, Guowei; Lei, Bo

    2013-09-01

    The existence of non-uniformities in the responsitivity of the element array is a severe problem typical to common infrared detector. These non-uniformities result in a "curtain'' like fixed pattern noises (FPN) that appear in the image. Some random noise can be restrained by the method kind of equalization method. But the fixed pattern noise can only be removed by .non uniformity correction method. The produce of non uniformities of detector array is the combined action of infrared detector array, readout circuit, semiconductor device performance, the amplifier circuit and optical system. Conventional linear correction techniques require costly recalibration due to the drift of the detector or changes in temperature. Therefore, an adaptive non-uniformity method is needed to solve this problem. A lot factors including detectors and environment conditions variety are considered to analyze and conduct the cause of detector drift. Several experiments are designed to verify the guess. Based on the experiments, an adaptive non-uniformity correction method is put forward in this paper. The strength of this method lies in its simplicity and low computational complexity. Extensive experimental results demonstrate the disadvantage of traditional non-uniformity correct method is conquered by the proposed scheme.

  4. Apparatus and method for temperature correction and expanded count rate of inorganic scintillation detectors

    DOEpatents

    Ianakiev, Kiril D.; Hsue, Sin Tao; Browne, Michael C.; Audia, Jeffrey M.

    2006-07-25

    The present invention includes an apparatus and corresponding method for temperature correction and count rate expansion of inorganic scintillation detectors. A temperature sensor is attached to an inorganic scintillation detector. The inorganic scintillation detector, due to interaction with incident radiation, creates light pulse signals. A photoreceiver processes the light pulse signals to current signals. Temperature correction circuitry that uses a fast light component signal, a slow light component signal, and the temperature signal from the temperature sensor to corrected an inorganic scintillation detector signal output and expanded the count rate.

  5. Correction.

    PubMed

    2015-11-01

    In the article by Heuslein et al, which published online ahead of print on September 3, 2015 (DOI: 10.1161/ATVBAHA.115.305775), a correction was needed. Brett R. Blackman was added as the penultimate author of the article. The article has been corrected for publication in the November 2015 issue. PMID:26490278

  6. Note: Vignetting calibration and temperature correction for casting billets.

    PubMed

    Xie, Zhi; Zhang, Yuzhong; Hu, Zhenwei; Bai, Haicheng

    2013-09-01

    A method for calibration of vignetting coefficient is proposed in this paper to solve the distortion of temperature measurement using a CCD-based pyrometer. On this basis, a hybrid temperature measurement system, which comprises of an array CCD camera with high resolution and a single spot colorimetric thermometer, is introduced to eliminate the influences of surface striped iron oxide scale, dust, and emissivity on temperature measurement for casting billets. Currently, the system has been successfully applied and verified in some continuous casting production lines. The vignetting estimation error of 0.052 and the maximum temperature measurement fluctuation of 5 °C were achieved in these measurements.

  7. Note: Vignetting calibration and temperature correction for casting billets.

    PubMed

    Xie, Zhi; Zhang, Yuzhong; Hu, Zhenwei; Bai, Haicheng

    2013-09-01

    A method for calibration of vignetting coefficient is proposed in this paper to solve the distortion of temperature measurement using a CCD-based pyrometer. On this basis, a hybrid temperature measurement system, which comprises of an array CCD camera with high resolution and a single spot colorimetric thermometer, is introduced to eliminate the influences of surface striped iron oxide scale, dust, and emissivity on temperature measurement for casting billets. Currently, the system has been successfully applied and verified in some continuous casting production lines. The vignetting estimation error of 0.052 and the maximum temperature measurement fluctuation of 5 °C were achieved in these measurements. PMID:24089881

  8. Self-diffusion on the Lennard-Jones fcc(111) surface: Effects of temperature on dynamical corrections

    SciTech Connect

    Cohen, J.M.; Voter, A.F. , Los Alamos National Laboratory, Los Alamos, New Mexico 87545 )

    1989-10-15

    Surface self-diffusion constants have been calculated for the single component Lennard-Jones fcc(111) system using the dynamical corrections formalism for transition state theory (TST). At high temperatures, these results are found to be in agreement with previous molecular dynamics calculations. Over the extended temperature range in which this method is valid, deviations from Arrhenius behavior are observed. At lower temperatures, a noticeable contribution to the diffusion constant stems from trajectories in which the adatom recrosses the TST boundary, often due to a direction-reversing collision with the substrate atom on the far side of the binding site. This produces a dip in the dynamical correction factor centered around a reduced temperature of {ital T}=0.038. At higher temperatures, the expected multiple-jump effects are observed.

  9. Optical Diffraction Corrections in Radiometric Thermodynamic Temperature Determination

    NASA Astrophysics Data System (ADS)

    Briaudeau, S.; Rougié, B.; Sadli, M.; Richard, A.; Coutin, J. M.

    2009-02-01

    One of the main components of uncertainty in high-temperature thermometry arises because of the size-of-source effect (SSE). This effect makes the temperature measurement sensitive to the geometry of the radiating environment. It is caused by optical diffraction and especially by light scattering off/from, and inter-reflections between, optical components inside the pyrometer. The LNE-INM/CNAM is involved in extending the thermometry temperature scale to very high temperatures ( T > 2000 °C) and has developed eutectic-based fixed points (Sadli et al. (in: Zvizdic (ed.) Proceedings of TEMPMEKO 2004, 9th International Symposium on Temperature and Thermal Measurements in Industry and Science, 2004)) and a thermodynamic temperature measurement capability based on absolute radiometric methods (Briaudeau et al. (in: D. Zvizdic (ed.) Proceedings of TEMPMEKO 2004, 9th International Symposium on Temperature and Thermal Measurements in Industry and Science 2004)). A new measurement technique that uses an optical fiber has been developed and tested, allowing the determination of the SSE at any defocusing plane, with high resolution. A model based on optical diffraction has been developed to simulate the SSE in a real situation, considering the contribution to the pyrometer signal of the whole “3D” optical scene inside the blackbody furnace. Using the same approach, it has been demonstrated that optical scattering in a simple radiance meter can be estimated from accurate optical diffraction measurement.

  10. A New Correction Technique for Strain-Gage Measurements Acquired in Transient-Temperature Environments

    NASA Technical Reports Server (NTRS)

    Richards, W. Lance

    1996-01-01

    Significant strain-gage errors may exist in measurements acquired in transient-temperature environments if conventional correction methods are applied. As heating or cooling rates increase, temperature gradients between the strain-gage sensor and substrate surface increase proportionally. These temperature gradients introduce strain-measurement errors that are currently neglected in both conventional strain-correction theory and practice. Therefore, the conventional correction theory has been modified to account for these errors. A new experimental method has been developed to correct strain-gage measurements acquired in environments experiencing significant temperature transients. The new correction technique has been demonstrated through a series of tests in which strain measurements were acquired for temperature-rise rates ranging from 1 to greater than 100 degrees F/sec. Strain-gage data from these tests have been corrected with both the new and conventional methods and then compared with an analysis. Results show that, for temperature-rise rates greater than 10 degrees F/sec, the strain measurements corrected with the conventional technique produced strain errors that deviated from analysis by as much as 45 percent, whereas results corrected with the new technique were in good agreement with analytical results.

  11. Air Temperature Error Correction Based on Solar Radiation in an Economical Meteorological Wireless Sensor Network.

    PubMed

    Sun, Xingming; Yan, Shuangshuang; Wang, Baowei; Xia, Li; Liu, Qi; Zhang, Hui

    2015-01-01

    Air temperature (AT) is an extremely vital factor in meteorology, agriculture, military, etc., being used for the prediction of weather disasters, such as drought, flood, frost, etc. Many efforts have been made to monitor the temperature of the atmosphere, like automatic weather stations (AWS). Nevertheless, due to the high cost of specialized AT sensors, they cannot be deployed within a large spatial density. A novel method named the meteorology wireless sensor network relying on a sensing node has been proposed for the purpose of reducing the cost of AT monitoring. However, the temperature sensor on the sensing node can be easily influenced by environmental factors. Previous research has confirmed that there is a close relation between AT and solar radiation (SR). Therefore, this paper presents a method to decrease the error of sensed AT, taking SR into consideration. In this work, we analyzed all of the collected data of AT and SR in May 2014 and found the numerical correspondence between AT error (ATE) and SR. This corresponding relation was used to calculate real-time ATE according to real-time SR and to correct the error of AT in other months. PMID:26213941

  12. Air Temperature Error Correction Based on Solar Radiation in an Economical Meteorological Wireless Sensor Network

    PubMed Central

    Sun, Xingming; Yan, Shuangshuang; Wang, Baowei; Xia, Li; Liu, Qi; Zhang, Hui

    2015-01-01

    Air temperature (AT) is an extremely vital factor in meteorology, agriculture, military, etc., being used for the prediction of weather disasters, such as drought, flood, frost, etc. Many efforts have been made to monitor the temperature of the atmosphere, like automatic weather stations (AWS). Nevertheless, due to the high cost of specialized AT sensors, they cannot be deployed within a large spatial density. A novel method named the meteorology wireless sensor network relying on a sensing node has been proposed for the purpose of reducing the cost of AT monitoring. However, the temperature sensor on the sensing node can be easily influenced by environmental factors. Previous research has confirmed that there is a close relation between AT and solar radiation (SR). Therefore, this paper presents a method to decrease the error of sensed AT, taking SR into consideration. In this work, we analyzed all of the collected data of AT and SR in May 2014 and found the numerical correspondence between AT error (ATE) and SR. This corresponding relation was used to calculate real-time ATE according to real-time SR and to correct the error of AT in other months. PMID:26213941

  13. Next-to-leading-order correction to pion form factor in k{sub T} factorization

    SciTech Connect

    Li Hsiangnan; Shen Yuelong; Wang Yuming; Zou Hao

    2011-03-01

    We calculate the next-to-leading-order (NLO) correction to the pion electromagnetic form factor at leading twist in the k{sub T} factorization theorem. Partons off-shell by k{sub T}{sup 2} are considered in both quark diagrams and effective diagrams for the transverse-momentum-dependent pion wave function. The light-cone singularities in the transverse-momentum-dependent pion wave function are regularized by rotating the Wilson lines away from the light cone. The soft divergences from gluon exchanges among initial- and fal-state partons cancel exactly. We derive the infrared-finite k{sub T}-dependent NLO hard kernel for the pion electromagnetic form factor by taking the difference of the above two sets of diagrams. Varying the renormalization and factorization scales, we find that the NLO correction is smaller, when both the scales are set to the invariant masses of internal particles: it becomes lower than 40% of the leading-order contribution for momentum transfer squared Q{sup 2}>7 GeV{sup 2}. It is observed that the NLO leading-twist correction does not play an essential role in explaining the experimental data, but the leading-order higher-twist contribution does.

  14. Finite volume form factors and correlation functions at finite temperature

    NASA Astrophysics Data System (ADS)

    Pozsgay, Balázs

    2009-07-01

    In this thesis we investigate finite size effects in 1+1 dimensional integrable QFT. In particular we consider matrix elements of local operators (finite volume form factors) and vacuum expectation values and correlation functions at finite temperature. In the first part of the thesis we give a complete description of the finite volume form factors in terms of the infinite volume form factors (solutions of the bootstrap program) and the S-matrix of the theory. The calculations are correct to all orders in the inverse of the volume, only exponentially decaying (residual) finite size effects are neglected. We also consider matrix elements with disconnected pieces and determine the general rule for evaluating such contributions in a finite volume. The analytic results are tested against numerical data obtained by the truncated conformal space approach in the Lee-Yang model and the Ising model in a magnetic field. In a separate section we also evaluate the leading exponential correction (the μ-term) associated to multi-particle energies and matrix elements. In the second part of the thesis we show that finite volume factors can be used to derive a systematic low-temperature expansion for correlation functions at finite temperature. In the case of vacuum expectation values the series is worked out up to the third non-trivial order and a complete agreement with the LeClair-Mussardo formula is observed. A preliminary treatment of the two-point function is also given by considering the first nontrivial contributions.

  15. Corrections for temperature effect for ground-based muon hodoscopes

    NASA Astrophysics Data System (ADS)

    Dmitrieva, A. N.; Kokoulin, R. P.; Petrukhin, A. A.; Timashkov, D. A.

    2011-01-01

    Influence of atmospheric temperature on muon flux at sea level is considered. Results of calculations of muon spectrum for normal atmospheric conditions, differential temperature coefficients (DTC) for muons at different zenith angles and threshold energies are presented. In calculations, a six-layer stationary spherical model of atmosphere is used, contributions of both pions and kaons as well as dependence of muon energy loss on muon energy are taken into account. Comparison of muon spectrum calculations and experimental data in a wide range of zenith angles and momentums shows a good agreement. Comparison of results of DTC calculations with results of earlier works exhibits only qualitative agreement; possible sources of differences are analyzed. Some practical questions of the use of DTC for muon hodoscope data analysis are discussed.

  16. Experimental validation of beam quality correction factors for proton beams.

    PubMed

    Gomà, Carles; Hofstetter-Boillat, Bénédicte; Safai, Sairos; Vörös, Sándor

    2015-04-21

    This paper presents a method to experimentally validate the beam quality correction factors (kQ) tabulated in IAEA TRS-398 for proton beams and to determine the kQ of non-tabulated ionization chambers (based on the already tabulated values). The method is based exclusively on ionometry and it consists in comparing the reading of two ionization chambers under the same reference conditions in a proton beam quality Q and a reference beam quality (60)Co. This allows one to experimentally determine the ratio between the kQ of the two ionization chambers. In this work, 7 different ionization chamber models were irradiated under the IAEA TRS-398 reference conditions for (60)Co beams and proton beams. For the latter, the reference conditions for both modulated beams (spread-out Bragg peak field) and monoenergetic beams (pseudo-monoenergetic field) were studied. For monoenergetic beams, it was found that the experimental kQ values obtained for plane-parallel chambers are consistent with the values tabulated in IAEA TRS-398; whereas the kQ values obtained for cylindrical chambers are not consistent--being higher than the tabulated values. These results support the suggestion (of previous publications) that the IAEA TRS-398 reference conditions for monoenergetic proton beams should be revised so that the effective point of measurement of cylindrical ionization chambers is taken into account when positioning the reference point of the chamber at the reference depth. For modulated proton beams, the tabulated kQ values of all the ionization chambers studied in this work were found to be consistent with each other--except for the IBA FC65-G, whose experimental kQ value was found to be 0.6% lower than the tabulated one. The kQ of the PTW Advanced Markus chamber, which is not tabulated in IAEA TRS-398, was found to be 0.997 ± 0.042 (k = 2), based on the tabulated value of the PTW Markus chamber.

  17. Corrections

    NASA Astrophysics Data System (ADS)

    2012-09-01

    The feature article "Material advantage?" on the effects of technology and rule changes on sporting performance (July pp28-30) stated that sprinters are less affected by lower oxygen levels at high altitudes because they run "aerobically". They run anaerobically. The feature about the search for the Higgs boson (August pp22-26) incorrectly gave the boson's mass as roughly 125 MeV it is 125 GeV, as correctly stated elsewhere in the issue. The article also gave a wrong value for the intended collision energy of the Superconducting Super Collider, which was designed to collide protons with a total energy of 40 TeV.

  18. A method to correct for temperature dependence and measure simultaneously dose and temperature using a plastic scintillation detector

    PubMed Central

    Therriault-Proulx, Francois; Wootton, Landon; Beddar, Sam

    2015-01-01

    Plastic scintillation detectors (PSDs) work well for radiation dosimetry. However, they show some temperature dependence, and a priori knowledge of the temperature surrounding the PSD is required to correct for this dependence. We present a novel approach to correct PSD response values for temperature changes instantaneously and without the need for prior knowledge of the temperature value. In addition to rendering the detector temperature-independent, this approach allows for actual temperature measurement using solely the PSD apparatus. With a temperature-controlled water tank, the temperature was varied from room temperature to more than 40°C and the PSD was used to measure the dose delivered from a cobalt-60 photon beam unit to within an average of 0.72% from the expected value. The temperature was measured during each acquisition with the PSD and a thermocouple and values were within 1°C of each other. The depth-dose curve of a 6-MV photon beam was also measured under warm non-stable conditions and this curve agreed to within an average of −0.98% from the curve obtained at room temperature. The feasibility of rendering PSDs temperature-independent was demonstrated with our approach, which also enabled simultaneous measurement of both dose and temperature. This novel approach improves both the robustness and versatility of PSDs. PMID:26407188

  19. Correction.

    PubMed

    2015-05-22

    The Circulation Research article by Keith and Bolli (“String Theory” of c-kitpos Cardiac Cells: A New Paradigm Regarding the Nature of These Cells That May Reconcile Apparently Discrepant Results. Circ Res. 2015:116:1216-1230. doi: 10.1161/CIRCRESAHA.116.305557) states that van Berlo et al (2014) observed that large numbers of fibroblasts and adventitial cells, some smooth muscle and endothelial cells, and rare cardiomyocytes originated from c-kit positive progenitors. However, van Berlo et al reported that only occasional fibroblasts and adventitial cells derived from c-kit positive progenitors in their studies. Accordingly, the review has been corrected to indicate that van Berlo et al (2014) observed that large numbers of endothelial cells, with some smooth muscle cells and fibroblasts, and more rarely cardiomyocytes, originated from c-kit positive progenitors in their murine model. The authors apologize for this error, and the error has been noted and corrected in the online version of the article, which is available at http://circres.ahajournals.org/content/116/7/1216.full ( PMID:25999426

  20. Real-Gas Correction Factors for Hypersonic Flow Parameters in Helium

    NASA Technical Reports Server (NTRS)

    Erickson, Wayne D.

    1960-01-01

    The real-gas hypersonic flow parameters for helium have been calculated for stagnation temperatures from 0 F to 600 F and stagnation pressures up to 6,000 pounds per square inch absolute. The results of these calculations are presented in the form of simple correction factors which must be applied to the tabulated ideal-gas parameters. It has been shown that the deviations from the ideal-gas law which exist at high pressures may cause a corresponding significant error in the hypersonic flow parameters when calculated as an ideal gas. For example the ratio of the free-stream static to stagnation pressure as calculated from the thermodynamic properties of helium for a stagnation temperature of 80 F and pressure of 4,000 pounds per square inch absolute was found to be approximately 13 percent greater than that determined from the ideal-gas tabulation with a specific heat ratio of 5/3.

  1. Economic comparison of power factor correction by capacitors and high power factor/high-efficiency motors

    SciTech Connect

    Slack, K.D.; Capehart, B.L.

    1998-12-01

    The traditional approach to power factor correction in a facility is to add capacitors to individual loads such as motors and fluorescent lighting circuits, to add a capacitor bank with switching to a major distribution panel, or to add a capacitor bank with switching to the power input panel from the utility lines. Recently it has been shown that careful selection of high-efficiency motors for a facility can result in new motors with a significantly higher power factor than the motors they replaced. This article compares and discusses the cost-effectiveness of installing capacitors on individual motors with the cost-effectiveness of installing high-efficiency, high power factor motors.

  2. Spatial correction factors for YALINA Booster facility loaded with medium and low enriched fuels

    SciTech Connect

    Talamo, A.; Gohar, Y.; Bournos, V.; Fokov, Y.; Kiyavitskaya, H.; Routkovskaya, C.

    2012-07-01

    The Bell and Glasstone spatial correction factor is used in analyses of subcritical assemblies to correct the experimental reactivity as function of the detector position. Besides the detector position, several other parameters affect the correction factor: the energy weighting function of the detector, the detector size, the energy-angle distribution of source neutrons, and the reactivity of the subcritical assembly. This work focuses on the dependency of the correction factor on the detector material and it investigates the YALINA Booster subcritical assembly loaded with medium (36%) and low (10%) enriched fuels. (authors)

  3. Two dimensional bias correction of temperature and precipitation copulas in climate models

    NASA Astrophysics Data System (ADS)

    Piani, C.; Haerter, J. O.

    2012-12-01

    In most climate model bias-correction procedures, temperature and precipitation are corrected independently, thereby degrading the dynamical link represented within the model. We propose a methodology that advances the state-of-the-art by correcting not just the independent intensity distributions but the full two-dimensional statistical distribution of temperature and precipitation as described by the copula. To illustrate the methodology and its potential to affect copulas, it was applied to a synthetic temperature and precipitation (T&P) dataset. Figure 1a shows two histograms derived from synthetic 2D T&P datasets. The dashed color-filled contours represent the simulated T&P data histogram while the solid contours represent the observed T&P data. The distribution shown in fig. 1e is the copula extracted from the synthetic observed T&P data set used to derive the non-colored 2D histogram shown in fig. 1a. The copula extracted from the simulated data is flat. In fig 1b (1c) the simulated 2D histogram has been bias corrected using linear (high order) 1D bias corrections separately for temperature and precipitation. Inspection of fig. 1b and 1c will reveal that the simple independent bias corrections of temperature and precipitation improve the 2D histogram greatly without affecting the copula at all. In fact the copulas derived from the 2D colored histograms in fig 1b and 1c are still flat! Finally, in fig. 1d, the full 2D bias correction is applied. Figure 1f shows the copula of the corrected data from fig. 1d. Now that we have applied the full 2D bias correction developed in this study, we obtain some structure in the derived copula. To assess the effectiveness of the proposed method, it is applied to the a regional climate model output and weather station data over Germany. A standard cross-validation is performed by dividing the data into two non overlapping 10 year periods. Results show that the methodology effectively improves the temperature

  4. Automatic correction scheme for the temperature dependent overlap function of CHM15k ceilometers

    NASA Astrophysics Data System (ADS)

    Haefele, Alexander; Poltera, Yann; Hervo, Maxime

    2016-04-01

    Imperfections in a lidar's overlap function lead to artefacts in the background, range and overlap corrected lidar signals. These artefacts can erroneously be interpreted as aerosol gradient or, in extreme cases, as cloud base leading to false cloud detection. A correct specification of the overlap function is hence crucial to use automatic elastic lidars (ceilometers) for the detection of the planetary boundary layer or low clouds. In this study an algorithm is presented to correct such artefacts. It is based on the assumption of a homogeneous boundary layer and a correct specification of the overlap function down to a minimum range, which must be situated within the boundary layer. The strength of the algorithm lies in a sophisticated quality check scheme which allows to reliably identify favorable atmospheric conditions. The algorithm has been applied to 2 years of data from a CHM15k ceilometer from Lufft. Backscatter signals corrected for background, range and overlap have been compared using the overlap function provided by the manufacturer and the one corrected with the presented algorithm. Differences between corrected and uncorrected signals reach up to 45% in the first 300m above ground. The amplitude of the correction turned out to be temperature dependent being larger for higher temperatures. A linear model of the correction as a function of the instrument's internal temperature has been derived from the experimental data. Case studies and a statistical analysis of the strongest gradient derived from corrected signals reveal that the temperature model is capable to correct overlap artefacts with high quality, in particular such due to diurnal variations. The presented correction method has the potential to significantly improve the detection of the boundary layer with gradient based methods because it removes false candidates and hence simplifies the attribution of the detected gradients to the planetary boundary layer. A particularly high benefit can be

  5. Intercomparison Of Bias-Correction Methods For Monthly Temperature And Precipitation Simulated By Multiple Climate Models

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Kanae, S.; Seto, S.; Hirabayashi, Y.; Oki, T.

    2012-12-01

    Bias-correction methods applied to monthly temperature and precipitation data simulated by multiple General Circulation Models (GCMs) are evaluated in this study. Although various methods have been proposed recently, an intercomparison among them using multiple GCM simulations has seldom been reported. Here, five previous methods as well as a proposed new method are compared. Before the comparison, we classified previous methods. The methods proposed in previous studies can be classified into four types based on the following two criteria: 1) Whether the statistics (e.g. mean, standard deviation, or the coefficient of variation) of future simulation is used in bias-correction; and 2) whether the estimation of cumulative probability is included in bias-correction. The methods which require future statistics will depend on the data in the projection period, while those which do not use future statistics are not. The classification proposed can characterize each bias-correction method. These methods are applied to temperature and precipitation simulated from 12 GCMs in the Coupled Model Intercomparison Project (CMIP3) archives. Parameters of each method are calibrated by using 1948-1972 observed data and validated for the 1974-1998 period. These methods are then applied to GCM future simulations (2073-2097), and the bias-corrected data are intercompared. For the historical simulation, negligible difference can be found between observed and bias-corrected data. However, the difference in the future simulation is large dependent on the characteristics of each method. The frequency (probability) that the 2073-2097 bias-corrected data exceed the 95th percentile of the 1948-1972 observed data is estimated in order to evaluate the differences among methods. The difference between proposed and one of the previous method is more than 10% in many areas. The differences of bias-corrected data among methods are discussed based on their respective characteristics. The results

  6. Experimental verification of Theodorsen's theoretical jet-boundary correction factors

    NASA Technical Reports Server (NTRS)

    Schliestett, George Van

    1934-01-01

    Prandtl's suggested use of a doubly infinite arrangement of airfoil images in the theoretical determination of wind-tunnel jet-boundary corrections was first adapted by Glauert to the case of closed rectangular jets. More recently, Theodorsen, using the same image arrangement but a different analytical treatment, has extended this work to include not only closed but also partly closed and open tunnels. This report presents the results of wind-tunnel tests conducted at the Georgia School of Technology for the purpose of verifying the five cases analyzed by Theodorsen. The tests were conducted in a square tunnel and the results constitute a satisfactory verification of his general method of analysis. During the preparation of the data two minor errors were discovered in the theory and these have been rectified.

  7. Three-Dimensional Thermal Boundary Layer Corrections for Circular Heat Flux Gauges Mounted in a Flat Plate with a Surface Temperature Discontinuity

    NASA Technical Reports Server (NTRS)

    Kandula, M.; Haddad, G. F.; Chen, R.-H.

    2006-01-01

    Three-dimensional Navier-Stokes computational fluid dynamics (CFD) analysis has been performed in an effort to determine thermal boundary layer correction factors for circular convective heat flux gauges (such as Schmidt-Boelter and plug type)mounted flush in a flat plate subjected to a stepwise surface temperature discontinuity. Turbulent flow solutions with temperature-dependent properties are obtained for a free stream Reynolds number of 1E6, and freestream Mach numbers of 2 and 4. The effect of gauge diameter and the plate surface temperature have been investigated. The 3-D CFD results for the heat flux correction factors are compared to quasi-21) results deduced from constant property integral solutions and also 2-D CFD analysis with both constant and variable properties. The role of three-dimensionality and of property variations on the heat flux correction factors has been demonstrated.

  8. Non-uniformity correction with temperature influence compensation in microbolometer detector

    NASA Astrophysics Data System (ADS)

    Krupiński, Michał; Bieszczad, Grzegorz; Gogler, Sławomir; Madura, Henryk

    2015-05-01

    Because of a significant impact of the microbolometer array temperature on the infrared image quality, it is necessary to compensate the influence of the temperature on the NUC process. In the most common applications two approaches are used: the first is a stabilization of the microbolometer array temperature by a thermoelectric cooler, the second is updating correction coefficients obtained from reference source, for example a shutter [14]. Both of the most common approaches have theirs disadvantages. The first case needs a considerable amount of energy for temperature stabilisation. The second one needs a reference target and a mechanical procedure to place the target at the front of the detector. Additionally, during calibration the reference target is blocking radiation from the scene, thus interrupting measurements with the thermal camera. In the article a non-uniformity correction method is presented which allows to compensate for the influence of detector's temperature drift. For this purpose, dependency between output signal value and the temperature of the detector array was investigated. Additionally the influence of the temperature on the Offset and Gain coefficients was measured. Presented method utilizes estimated dependency between output signal of detectors and their temperature. In the presented method, the dependency between output signal value and the temperature of the detector is estimated during time of starting detector. The coefficients are estimated for every pixel. In the article proposed method allows to compensate the influence of detectors temperature fluctuation and increase a time between shutter actuation process.

  9. Reproduction of surface air temperature over South Korea using dynamical downscaling and statistical correction

    NASA Astrophysics Data System (ADS)

    Ahn, J.; Lee, J.; Shim, K.; Kim, Y.

    2013-12-01

    In spite of dense meteorological observation conducting over South Korea (The average distance between stations: ~ 12.7km), the detailed topographical effect is not reflected properly due to its mountainous terrains and observation sites mostly situated on low altitudes. A model represents such a topographical effect well, but due to systematic biases in the model, the general temperature distribution is sometimes far different from actual observation. This study attempts to produce a detailed mean temperature distribution for South Korea through a method combining dynamical downscaling and statistical correction. For the dynamical downscaling, a multi-nesting technique is applied to obtain 3-km resolution data with a focus on the domain for the period of 10 years (1999-2008). For the correction of systematic biases, a perturbation method divided into the mean and the perturbation part was used with a different correction method being applied to each part. The mean was corrected by a weighting function while the perturbation was corrected by the self-organizing maps method. The results with correction agree well with the observed pattern compared to those without correction, improving the spatial and temporal correlations as well as the RMSE. In addition, they represented detailed spatial features of temperature including topographic signals, which cannot be expressed properly by gridded observation. Through comparison with in-situ observation with gridded values after objective analysis, it was found that the detailed structure correctly reflected topographically diverse signals that could not be derived from limited observation data. We expect that the correction method developed in this study can be effectively used for the analyses and projections of climate downscaled by using region climate models. Acknowledgements This work was carried out with the support of Korea Meteorological Administration Research and Development Program under Grant CATER 2012-3083 and

  10. [Occupational risk factors and medical prevention in corrections officers].

    PubMed

    Mennoial, Nunzio Valerio; Napoli, Paola; Battaglia, Andrea; Candura, Stefano M

    2014-01-01

    In Italy, the Law n. 395/1990 defines the tasks and attributions of prison officers. According to the article 25 of the Legislative Decree n. 81/2008, the occupational physician should participate to risk assessment, and carry out the sanitary surveillance. This report analyzes the various tasks of prison staff, identifies the risk factors, and discusses the preventive strategies, including workers formation and education. Biological agents and work-related stress are the main risk factors, as a consequence of prison overcrowding, personnel shortage and work organization complexity. In his preventive action, and particularly in formulating the judgment on work fitness, the occupational physician often clashes with inadequate ministerial funding.

  11. Mach-uniformity through the coupled pressure and temperature correction algorithm

    SciTech Connect

    Nerinckx, Krista . E-mail: Krista.Nerinckx@UGent.be; Vierendeels, Jan . E-mail: Jan.Vierendeels@UGent.be; Dick, Erik . E-mail: Erik.Dick@UGent.be

    2005-07-01

    We present a new type of algorithm: the coupled pressure and temperature correction algorithm. It is situated in between the fully coupled and the fully segregated approach, and is constructed such that Mach-uniform accuracy and efficiency are obtained. The essential idea is the separation of the convective and the acoustic/thermodynamic phenomena: a convective predictor is followed by an acoustic/thermodynamic corrector. For a general case, the corrector consists of a coupled solution of the energy and the continuity equations for both pressure and temperature corrections. For the special case of an adiabatic perfect gas flow, the algorithm reduces to a fully segregated method, with a pressure-correction equation based on the energy equation. Various test cases are considered, which confirm that Mach-uniformity is obtained.

  12. Intercomparison of bias-correction methods for monthly temperature and precipitation simulated by multiple climate models

    NASA Astrophysics Data System (ADS)

    Watanabe, Satoshi; Kanae, Shinjiro; Seto, Shinta; Yeh, Pat J.-F.; Hirabayashi, Yukiko; Oki, Taikan

    2012-12-01

    Bias-correction methods applied to monthly temperature and precipitation data simulated by multiple General Circulation Models (GCMs) are evaluated in this study. Although various methods have been proposed recently, an intercomparison among them using multiple GCM simulations has seldom been reported. Moreover, no previous methods have addressed the issue how to adequately deal with the changes of the statistics of bias-corrected variables from the historical to future simulations. In this study, a new method which conserves the changes of mean and standard deviation of the uncorrected model simulation data is proposed, and then five previous bias-correction methods as well as the proposed new method are intercompared by applying them to monthly temperature and precipitation data simulated from 12 GCMs in the Coupled Model Intercomparison Project (CMIP3) archives. Parameters of each method are calibrated by using 1948-1972 observed data and validated in the 1974-1998 period. These methods are then applied to the GCM future simulations (2073-2097) and the bias-corrected data are intercompared. For the historical simulations, negligible difference can be found between observed and bias-corrected data. However, the differences in future simulations are large dependent on the characteristics of each method. The new method successfully conserves the changes in the mean, standard deviation and the coefficient of variation before and after bias-correction. The differences of bias-corrected data among methods are discussed according to their respective characteristics. Importantly, this study classifies available correction methods into two distinct categories, and articulates important features for each of them.

  13. Methyl bromide emissions from a covered field: III. Correcting chamber flux for temperature

    SciTech Connect

    Yates, S.R.; Gan, J.; Ernst, F.F.; Wang, D.

    1996-07-01

    An experiment was conducted to investigate the environmental fate and transport of methyl bromide (MeBr) in agricultural systems. Part of this experiment involved the use of three flow-through chambers to estimate the MeBr flux through a sheet of clear polyethylene plastic covering the field. Using the chamber data, the total mass lost to the atmosphere was estimated to be 96% of the applied mass, and the results were highly variable between chambers (i.e., standard deviation of 298 kg or 35%). The air temperature inside the chamber was found to be much higher than the air temperature outside and was highly correlated with the diurnal variation in incoming solar radiation. Since the diffusion through polyethylene film was found to be strongly dependent on the temperature, a method was developed to correct the chamber flux density data for enhanced diffusion caused by increases in the temperature inside the chamber. After correcting for temperature, the estimated total MeBr emission was reduced to approximately 59% (21% standard deviation) of the applied amount, which is about 5% less than was measured using other methods. When chambers are used to measure volatilization of MeBr or other fumigants from fields covered with a sheet of polyethylene plastic, the chambers should be designed to minimize internal heating or some method should be used to correct the volatilization rate for the effects of temperature. 16 refs., 5 figs., 1 tab.

  14. Skin Temperature Analysis and Bias Correction in a Coupled Land-Atmosphere Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Radakovich, Jon D.; daSilva, Arlindo; Todling, Ricardo; Verter, Frances

    2006-01-01

    In an initial investigation, remotely sensed surface temperature is assimilated into a coupled atmosphere/land global data assimilation system, with explicit accounting for biases in the model state. In this scheme, an incremental bias correction term is introduced in the model's surface energy budget. In its simplest form, the algorithm estimates and corrects a constant time mean bias for each gridpoint; additional benefits are attained with a refined version of the algorithm which allows for a correction of the mean diurnal cycle. The method is validated against the assimilated observations, as well as independent near-surface air temperature observations. In many regions, not accounting for the diurnal cycle of bias caused degradation of the diurnal amplitude of background model air temperature. Energy fluxes collected through the Coordinated Enhanced Observing Period (CEOP) are used to more closely inspect the surface energy budget. In general, sensible heat flux is improved with the surface temperature assimilation, and two stations show a reduction of bias by as much as 30 Wm(sup -2) Rondonia station in Amazonia, the Bowen ratio changes direction in an improvement related to the temperature assimilation. However, at many stations the monthly latent heat flux bias is slightly increased. These results show the impact of univariate assimilation of surface temperature observations on the surface energy budget, and suggest the need for multivariate land data assimilation. The results also show the need for independent validation data, especially flux stations in varied climate regimes.

  15. Implementation of Coupled Skin Temperature Analysis and Bias Correction in a Global Atmospheric Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Radakovich, Jon; Bosilovich, M.; Chern, Jiun-dar; daSilva, Arlindo

    2004-01-01

    The NASA/NCAR Finite Volume GCM (fvGCM) with the NCAR CLM (Community Land Model) version 2.0 was integrated into the NASA/GMAO Finite Volume Data Assimilation System (fvDAS). A new method was developed for coupled skin temperature assimilation and bias correction where the analysis increment and bias correction term is passed into the CLM2 and considered a forcing term in the solution to the energy balance. For our purposes, the fvDAS CLM2 was run at 1 deg. x 1.25 deg. horizontal resolution with 55 vertical levels. We assimilate the ISCCP-DX (30 km resolution) surface temperature product. The atmospheric analysis was performed 6-hourly, while the skin temperature analysis was performed 3-hourly. The bias correction term, which was updated at the analysis times, was added to the skin temperature tendency equation at every timestep. In this presentation, we focus on the validation of the surface energy budget at the in situ reference sites for the Coordinated Enhanced Observation Period (CEOP). We will concentrate on sites that include independent skin temperature measurements and complete energy budget observations for the month of July 2001. In addition, MODIS skin temperature will be used for validation. Several assimilations were conducted and preliminary results will be presented.

  16. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 34 2012-07-01 2012-07-01 false NOX intake-air humidity...

  17. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 34 2013-07-01 2013-07-01 false NOX intake-air humidity...

  18. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 33 2011-07-01 2011-07-01 false NOX intake-air humidity...

  19. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 33 2014-07-01 2014-07-01 false NOX intake-air humidity...

  20. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 32 2010-07-01 2010-07-01 false NOX intake-air humidity...

  1. A modification of the Avrett-Krook temperature-correction procedure.

    NASA Technical Reports Server (NTRS)

    Karp, A. H.

    1972-01-01

    In the course of developing a computer program for blanketed model stellar atmospheres, it was found that near the surface the Avrett-Krook temperature correction procedure (1963) has poor convergence properties. The problem is most apparent when frequencies shortward of the Lyman discontinuity are included. Slightly different assumptions have been made to improve the convergence.

  2. OBSERVATIONS OF SIMILARITY THEORY STABILITY CORRECTION TERMS FOR MOMENTUM AND TEMPERATURE, OVER AGRICULTURAL FIELDS AND FORESTS.

    EPA Science Inventory

    Many observations of temperature and wind speed profiles have been taken over "ideal" terrain and analyzed to develop the stability correction terms which are commonly used in the application of similarity theory. Fewer observations have been taken and analyzed in this manner ov...

  3. An improved method for correction of air temperature measured using different radiation shields

    NASA Astrophysics Data System (ADS)

    Cheng, Xinghong; Su, Debin; Li, Deping; Chen, Lu; Xu, Wenjing; Yang, Meilin; Li, Yongcheng; Yue, Zhizhong; Wang, Zijing

    2014-11-01

    The variation of air temperature measurement errors using two different radiation shields (DTR502B Vaisala, Finland, and HYTFZ01, Huayun Tongda Satcom, China) was studied. Datasets were collected in the field at the Daxing weather station in Beijing from June 2011 to May 2012. Most air temperature values obtained with these two commonly used radiation shields were lower than the reference records obtained with the new Fiber Reinforced Polymers (FRP) Stevenson screen. In most cases, the air temperature errors when using the two devices were smaller on overcast and rainy days than on sunny days; and smaller when using the imported rather than the Chinese shield. The measured errors changed sharply at sunrise and sunset, and reached maxima at noon. Their diurnal variation characteristics were, naturally, related to changes in solar radiation. The relationships between the record errors, global radiation, and wind speed were nonlinear. An improved correction method was proposed based on the approach described by Nakamura and Mahrt (2005) (NM05), in which the impact of the solar zenith angle (SZA) on the temperature error is considered and extreme errors due to changes in SZA can be corrected effectively. Measurement errors were reduced significantly after correction by either method for both shields. The error reduction rate using the improved correction method for the Chinese and imported shields were 3.3% and 40.4% higher than those using the NM05 method, respectively.

  4. Factors Influencing the Design, Establishment, Administration, and Governance of Correctional Education for Females

    ERIC Educational Resources Information Center

    Ellis, Johnica; McFadden, Cheryl; Colaric, Susan

    2008-01-01

    This article summarizes the results of a study conducted to investigate factors influencing the organizational design, establishment, administration, and governance of correctional education for females. The research involved interviews with correctional and community college administrators and practitioners representing North Carolina female…

  5. New soft tissue correction factors for stature estimation: results from magnetic resonance imaging.

    PubMed

    Bidmos, Mubarak Ariyo; Manger, Paul Robert

    2012-01-10

    In stature reconstruction using Fully's method, it is essential that a soft tissue correction factor be added to skeletal height in order to obtain an estimate of living stature. While some anthropologists consider Fully's method to be the most reliable for stature estimation, others consider it to be inadequate as it seems to be underestimating living stature, possibly due to an error in the magnitude of Fully's soft tissue factors. A recent study by Raxter and co-workers revised Fully's technique and also presented a new "universally applicable" soft tissue correction factor. The present study examines the reliability of soft tissue correction factors of Fully and Raxter et al. on a living sample of indigenous South African males. The current study is based on data collected from 28 indigenous South African (ISA) male volunteers. Standing height of each subject was measured using a stadiometer. Fully's method was used in the calculation of total skeletal height from a full body MRI scan of each subject. Subsequent analyses of the acquired data revealed that the previously derived soft tissue correction factors are not applicable to the studied sample, and why they are not applicable. The correction factors of Fully and Raxter et al. both significantly underestimate living stature in a living sample of indigenous South African males. Consequently, a new correction factor was calculated based on the prediction of living stature from TSH using regression analysis.

  6. PTRAC File Utilization for Calculation of Free-Air Ionization Chamber Correction Factors by MCNPX

    NASA Astrophysics Data System (ADS)

    Šolc, Jaroslav; Sochor, Vladimír

    2014-06-01

    A free-air ionization chamber is used as a standard of photon air-kerma. Several correction factors are applied to the air-kerma value. Correction factors for electron loss (kloss) and for additional ionization current caused by photon scatter (ksc), photon fluorescence (kfl), photon transmission through diaphragm edge (kdtr), and photon scatter from the surface of the diaphragm aperture (kdsc) were determined by the MCNPX code utilizing information stored in Particle Track (PTRAC) output files. Individual steps of the procedure are described and the calculated values of the correction factors are presented. The values are in agreement with the correction factors published in a literature for similar free-air chambers.

  7. 75 FR 5536 - Pipeline Safety: Control Room Management/Human Factors, Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-03

    ... Safety: Control Room Management/Human Factors, Correction AGENCY: Pipeline and Hazardous Materials Safety... Regulations to address human factors and other aspects of control room management for pipelines where... 63310) entitled ``Pipeline Safety: Control Room Management/Human Factors.'' This final rule...

  8. [Temperature effect correction for Chang'E-3 alpha particle X-ray spectrometer].

    PubMed

    Wu, Ming-Ye; Wang, Huan-Yu; Peng, Wen-Xi; Zhang, Cheng-Mo; Zhang, Jia-Yu; Cui, Xing-Zhu; Liang, Xiao-Hua; Wang, Jin-Zhou; Yang, Jia-Wei; Fan, Rui-Rui; Liu, Ya-Qing; Dong, Yi-Fan; Wu, Feng; Zhao, Xiao-Yun

    2012-07-01

    Alpha particle X-ray spectrometer (APXS) is one of the payloads of Chang'E-3 lunar rover of China's Lunar Exploration Project. The present paper introduces briefly the components of APXS, how it works and its working environment on the lunar surface. The environmental temperature effect has been studied with simulations and experiments, and the results show that the temperature of the APXS sensor will be varying during the measuring on the lunar surface. And another experiment reveals that the energy resolution becomes worse if the sensor's temperature is varying. In this paper, a correction method based on Pearson's chi-squared test is presented. The method can improve the energy resolution when the sensor's temperature is varying. We have tested the method with the spectra acquired by APXS in the temperature varying period of Temperature Cycling Test, and the results show that the method is efficient and reliable.

  9. Ising spin glasses: Corrections to finite size scaling, freezing temperatures, and critical exponents

    NASA Astrophysics Data System (ADS)

    Mari, P. O.; Campbell, I. A.

    1999-03-01

    We compare simulation data from different sources on two canonical three-dimensional Ising spin glasses (ISGs): the binomial +/-J near-neighbor interaction ISG and the Gaussian interaction ISG. We allow for the possibility of corrections to finite size scaling and estimate the correction exponent w. Consistent estimates for the critical temperatures Tg and for the critical exponents for each system are obtained. The data strongly indicate that critical exponents in the two systems are significantly different from each other. These results thus confirm a breakdown of standard universality rules in Ising spin glasses.

  10. Correction of Proton Resonance Frequency Shift Temperature Maps for Magnetic Field Disturbances Caused by Breathing

    NASA Astrophysics Data System (ADS)

    Shmatukha, Andriy V.; Bakker, Chris J. G.

    2006-05-01

    Respiratory Induced Resonance Offset (RIRO) is a periodic disturbance of the magnetic field due to breathing. Such disturbances handicap the accuracy of the Proton Resonance Frequency Shift (PRFS) method of MRI temperature mapping in anatomies situated nearby the lungs and chest wall. In this work, we propose a method capable of minimizing errors caused by RIRO in PRFS temperature maps. In this method, a set of baseline images characterizing RIRO at a variety of respiratory cycle instants is acquired before the thermal treatment starts. During the treatment, the temperature evolution is found from two successive images. Then, the calculated temperature changes are corrected for the additional contribution caused by RIRO using the pre-treatment baseline images acquired at the identical instances of the respiratory cycle. Our method is shown to improve the accuracy and stability of PRFS temperature maps in the presence of RIRO and motion in phantom and volunteer experiments.

  11. Evaluating atmospheric correction models for retrieving surface temperatures from the AVHRR over a tallgrass prairie

    NASA Technical Reports Server (NTRS)

    Cooper, D. I.; Asrar, G.

    1989-01-01

    The effects of atmospheric attenuation on surface radiative temperatures obtained by the AVHRR over a tallgrass prairie area in the Flint Hills of Kansas are examined. Six atmospheric correction models developed primarily for sea-surface temperature studies are used to test their utility for retrieval of radiative temperatures over the land surface. An uncertainty of + or - 3.0 C was found for the AVHRR data, and used to evaluate the performance of a given model. When the difference between in situ and AVHRR surface temperatures was smaller than the uncertainty, the model was judged to be adequate. Among the six models evaluated, only the NOAA split-window model consistently adjusted the AVHRR surface temperatures within + or - 3.0 C of the in situ measurements.

  12. Evaluating sedimentary basins for geothermal power production potential and bottom-hole temperature corrections

    NASA Astrophysics Data System (ADS)

    Crowell, Anna M.

    At present, the risks and costs associated with geothermal energy wildcat exploration are prohibitive. With improved technology, the future may be brighter, and a play fairway analysis, for geothermal exploration can guide development. Comparing geophysical data with geothermal gradient allows identification of potentially economic areas of interest. The play fairway analysis is a common tool used by the petroleum industry to identify areas for potential exploration. The analysis identifies areas in the Denver, Illinois, Michigan, and Williston Basins with the highest development potential. A great deal of data have potential for a play fairway analysis, but data quality is problematic due to systematic errors in bottom-hole temperatures (BHTs). Corrections to bottom-hole temperatures are necessary due to the perturbation of temperature caused by the drilling mud, and can range from 5 to 30 °C. Correction schemes for bottom-hole temperatures can be applied to both the energy-in-place estimates and play fairway analyses. The Harrison equation is the most accurate for basins less than 4.5 km deep. The Kehle correction is the most accurate for basins deeper than 4.5 km. Chapter II explains why BHTs grouped by depth are more statistically robust than those grouped by geochronological unit. Chapter III demonstrates why the Harrison Equation is the best correction method to use for BHTs. Chapters IV and V give the volumetric energy-in-place for the Denver, Illinois, and Michigan Basins for discrete temperature ranges, and Chapter 6 provides the final Play Fairway Favorability maps.

  13. Correction of sound velocity depending on the temperature for unconsolidated marine sediment

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Choul

    2016-04-01

    laboratory sound velocity measurements with systematic temperature change on unconsolidated marine sediment have been performed to establish the precise correction curves between temperature and the sound velocity. Piston and box core samples recovered from the East Sea and the South Sea of Korea were used for the measurement. The core samples were cooled (at temperature of nearly 0℃) and the temperature was gradually increased (from 0℃ to 30℃) to measure sound velocity depending on the changes in temperature. The sediment texture and physical properties (porosity, water content, and bulk density) were measured separately at the same depth. The rate of velocity increase for muddy, silty, and sandy sediment are about 2.63 m/s/℃, 2.74 m/s/℃, and 2.96 m/s/℃, respectively. This is similar to the velocity change rate, 2.97 m/s/℃ presented by Del Grosso (1952). The samples used in this research, however, have relatively higher porosity than those of Del Grosso (1952). Thus, the possibility of discrepancy is differences in water content which affect the sound velocity and measurement system. We used recently developed digital velocity measurement system using PXI based on LabVIEW. We suggest to employ this correction for the accurate in situ geoacoustic property from laboratory data particularly for the deep cold water sample such as the East Sea sediment that has very low bottom water temperature about 0℃. Keywords : in situ geoacoustic property, temperature correction, East Sea Acknowledgements: This research was supported by the Agency for Defense Development (UD14003DD) and by "Marine geological and geophysical mapping of the Korean seas" of the Korea Institute of Geoscience and Mineral Resources (KIGAM).

  14. Temperature effects and corrections in volume measurements based on liquid-level detection

    SciTech Connect

    Suda, S.; Keisch, B.

    1993-08-01

    Temperature changes affect volume measurements in several ways. The dimensions of the tank, and the density and level of the liquid it contains vary with temperature. In addition, the response signal of the sensor and hence the response of the liquid-level detection device may change with temperature. Level measurement devices can be grouped according to four measurement points of reference: tip of probe, response proportional to the length of probe, top of tank, and liquid surface. This paper describes the physical principles of pressure, capacitance probe, sonic reflections, and visual scales. These are representative of the four types of liquid level detection techniques. Development of the temperature correction algorithm requires that the measurement process be clearly defined, conditions or limitations specified, and that a temperature-effects test be run. Although not difficult or necessarily time-consuming to run, good practice requires a test plan following demonstrated guidelines. Measurement control procedures for remeasurement of the process solution in the tank during normal operation can provide data to validate temperature correction algorithms.

  15. A Useful Tool for Atmospheric Correction and Surface Temperature Estimation of Landsat Infrared Thermal Data

    NASA Astrophysics Data System (ADS)

    Rivalland, Vincent; Tardy, Benjamin; Huc, Mireille; Hagolle, Olivier; Marcq, Sébastien; Boulet, Gilles

    2016-04-01

    Land Surface temperature (LST) is a critical variable for studying the energy and water budgets at the Earth surface, and is a key component of many aspects of climate research and services. The Landsat program jointly carried out by NASA and USGS has been providing thermal infrared data for 40 years, but no associated LST product has been yet routinely proposed to community. To derive LST values, radiances measured at sensor-level need to be corrected for the atmospheric absorption, the atmospheric emission and the surface emissivity effect. Until now, existing LST products have been generated with multi channel methods such as the Temperature/Emissivity Separation (TES) adapted to ASTER data or the generalized split-window algorithm adapted to MODIS multispectral data. Those approaches are ill-adapted to the Landsat mono-window data specificity. The atmospheric correction methodology usually used for Landsat data requires detailed information about the state of the atmosphere. This information may be obtained from radio-sounding or model atmospheric reanalysis and is supplied to a radiative transfer model in order to estimate atmospheric parameters for a given coordinate. In this work, we present a new automatic tool dedicated to Landsat thermal data correction which improves the common atmospheric correction methodology by introducing the spatial dimension in the process. The python tool developed during this study, named LANDARTs for LANDsat Automatic Retrieval of surface Temperature, is fully automatic and provides atmospheric corrections for a whole Landsat tile. Vertical atmospheric conditions are downloaded from the ERA Interim dataset from ECMWF meteorological organization which provides them at 0.125 degrees resolution, at a global scale and with a 6-hour-time step. The atmospheric correction parameters are estimated on the atmospheric grid using the commercial software MODTRAN, then interpolated to 30m resolution. We detail the processing steps

  16. Communication: The Effect of Dispersion Corrections on the Melting Temperature of Liquid Water

    SciTech Connect

    Yoo, Soohaeng; Xantheas, Sotiris S.

    2011-03-28

    We report the results of the melting temperature (Tm) of liquid water for the Becke-Lee- Yang-Parr (BLYP) density functional including Dispersion corrections (BLYP-D) and the TTM3-F ab-initio based classical potential via constant pressure and constant enthalpy (NPH) ensemble molecular dynamics simulations of an ice Ih-liquid coexisting system. The inclusion of dispersion corrections to BLYP lowers the melting temperature of liquid water to Tm=360 K, which is a large improvement over the value of Tm > 400 K obtained with the original BLYP functional. The ab-initio based flexible, polarizable Thole-type model (TTM3-F) produces Tm=248 K from classical molecular dynamics simulations.

  17. REFINEMENT OF THE STREAM TEMPERATURE NETWORK MODEL WITH CORRECTIONS FOR SOLAR SHADINGS AND INFLOW TEMPERATURES

    NASA Astrophysics Data System (ADS)

    Miyamoto, Hitoshi; Maeba, Hiroshi; Nakayama, Kazuya; Michioku, Kohji

    A basin-wide stream network model was developed for stream temperature prediction in a river basin. The model used Horton’s geomorphologic laws for channel networks and river basins with stream ordering systems in order to connect channel segments from sources to the river mouth. Within the each segment, a theoretical solution derived from a thermal energy equation was used to predict longitudinal variation of stream temperatures. The model also took into account effects of solar radiation reduction due to both riparian vegetation and topography, thermal advection from the sources and lateral land-use. Comparison of the model prediction with observation in the Ibo River Basin of Japan showed very good agreement for the thermal structure throughout the river basin for almost all seasons, excluding the autumnal month in which the thermal budget on the stream water body was changed from positive to negative.

  18. Characterization and Correction of Aquarius Long Term Calibration Drift Using On-Earth Brightness Temperature Refernces

    NASA Technical Reports Server (NTRS)

    Brown, Shannon; Misra, Sidharth

    2013-01-01

    The Aquarius/SAC-D mission was launched on June 10, 2011 from Vandenberg Air Force Base. Aquarius consists of an L-band radiometer and scatterometer intended to provide global maps of sea surface salinity. One of the main mission objectives is to provide monthly global salinity maps for climate studies of ocean circulation, surface evaporation and precipitation, air/sea interactions and other processes. Therefore, it is critical that any spatial or temporal systematic biases be characterized and corrected. One of the main mission requirements is to measure salinity with an accuracy of 0.2 psu on montly time scales which requires a brightness temperature stability of about 0.1K, which is a challenging requirement for the radiometer. A secondary use of the Aquarius data is for soil moisture applications, which requires brightness temperature stability at the warmer end of the brightness temperature dynamic range. Soon after launch, time variable drifts were observed in the Aquarius data compared to in-situ data from ARGO and models for the ocean surface salinity. These drifts could arise from a number of sources, including the various components of the retrieval algorithm, such as the correction for direct and reflected galactic emission, or from the instrument brightness temperature calibration. If arising from the brightness temperature calibration, they could have gain and offset components. It is critical that the nature of the drifts be understood before a suitable correction can be implemented. This paper describes the approach that was used to detect and characterize the components of the drift that were in the brightness temperature calibration using on-Earth reference targets that were independent of the ocean model.

  19. Empirical effective temperatures and bolometric corrections for early-type stars

    NASA Technical Reports Server (NTRS)

    Code, A. D.; Bless, R. C.; Davis, J.; Brown, R. H.

    1976-01-01

    An empirical effective temperature for a star can be found by measuring its apparent angular diameter and absolute flux distribution. The angular diameters of 32 bright stars in the spectral range O5f to F8 have recently been measured with the stellar interferometer at Narrabri Observatory, and their absolute flux distributions have been found by combining observations of ultraviolet flux from the Orbiting Astronomical Observatory (OAO-2) with ground-based photometry. In this paper, these data have been combined to derive empirical effective temperatures and bolometric corrections for these 32 stars.

  20. Short-Wave Near-Infrared Spectrometer for Alcohol Determination and Temperature Correction

    PubMed Central

    Fu, Qingbo; Wang, Jinming; Lin, Guannan; Suo, Hui; Zhao, Chun

    2012-01-01

    A multichannel short-wave near-infrared (SW-NIR) spectrometer module based on charge-coupled device (CCD) detection was designed. The design relied on a tungsten lamp enhanced by light emitting diodes, a fixed grating monochromator and a linear CCD array. The main advantages were high optical resolution and an optimized signal-to-noise ratio (0.24 nm and 500, resp.) in the whole wavelength range of 650 to 1100 nm. An application to alcohol determination using partial least squares calibration and the temperature correction was presented. It was found that the direct transfer method had significant systematic prediction errors due to temperature effect. Generalized least squares weighting (GLSW) method was utilized for temperature correction. After recalibration, the RMSEP found for the 25°C model was 0.53% v/v and errors of the same order of magnitude were obtained at other temperatures (15, 35 and 40°C). And an r2 better than 0.99 was achieved for each validation set. The possibility and accuracy of using the miniature SW-NIR spectrometer and GLSW transfer calibration method for alcohol determination at different temperatures were proven. And the analysis procedure was simple and fast, allowing a strict control of alcohol content in the wine industry. PMID:22649750

  1. Radiative-recoil corrections to hyperfine splitting: Polarization insertions in the muon factor

    SciTech Connect

    Eides, Michael I.; Shelyuto, Valery A.

    2009-09-01

    We consider three-loop radiative-recoil corrections to hyperfine splitting in muonium due to insertions of a one-loop polarization operator in the muon factor. The contribution produced by electron polarization insertions is enhanced by the large logarithm of the electron-muon mass ratio. We obtained all single-logarithmic and nonlogarithmic radiative-recoil corrections of order {alpha}{sup 3}(m/M)E{sub F} generated by the diagrams with electron and muon polarization insertions.

  2. Error correction of the Normalized Difference Vegetation Index and Brightness Temperature calculated from the AVHRR observations

    NASA Astrophysics Data System (ADS)

    Rahman, Mohammed Zahidur

    This thesis investigates Normalized Difference Vegetation Index (NDVI) and Brightness Temperature (BT) stability in the NOAA/NESDIS Global Vegetation Index (GVI) data during 1982-2003. This data was collected from five NOAA series satellites. We have proposed to apply Empirical distribution function (EDF) to improve the stability of the NDVI and BT data derived from the AVHRR sensor on NOAA polar orbiting satellite. The instability of data results from orbit degradation as well as the circuit drifts over the life or a satellite. Degradation of NDVI and BT over time and shifts of NDVI and BT between the satellites was estimated China data set, for it includes a wide variety or different ecosystems represented globally. It was found that data for the years 1988, 1992, 1993, 1994, 1995 and 2000 are not stable enough compared to other years because of satellite orbit drift, AVHRR sensor degradation, and also Mt Pinatubo volcanic eruption in 1992. We assume data from NOAA-7(1982, 1983), NOAA-9 (1985, 1986), NOAA-11(1989, 1990), NOAA-14(1996, 1997), and NOAA-16 (2001, 2002) to be standard because theses satellite's equator crossing time falls between 1330 and 1500. Data from this particular period of the day maximized the value of coefficients. The crux of the proposed correction procedure consists of dividing standard year's data sets into two subsets. The subset 1(standard data correction sets) is used for correcting unstable years and then corrected data for this years compared with the standard data in the subset 2 (standard data validation sets). In this dissertation, we apply EDF to correct this deficiency of data for the affected years. We normalize or correct data by the method of empirical distribution functions compared with the standard. Using these normalized values, we estimate new NDVI and BT time series which provides NDVI and BT data for these years that match in subset 2 that is used for data validation.

  3. Radiative corrections to the Casimir Pressure under the influence of temperature and external fields

    SciTech Connect

    Robaschik, D.; Scharonhorst, K.; Wieczorek, E.

    1987-03-01

    Generalizing the quantum field theory (QFT) with boundary conditions in covariant gauge to the case of finite temperature, we develop the quantum electrodynamics (QED) with boundary conditions in the Matsubara approach as well as in the thermofield formulation. We rederive the known results of the free-field theory for the pressure and the free energy of the Casimir problem. For infinitely thin plates we calculate the radiative corrections in second-order perturbation theory at finite temperature. Thereby it turns out that the calculation in of the vacuum energy at the vanishing temperature via the Z functional is much simplier than the calculation via the energy momentum tensor. This observation allows determination of the influence of static electromagnetic fields on the Casimir problem. copyright 1987 Academic Press, Inc.

  4. Using multistate dynamical corrections to compute classically exact diffusion constants at arbitrary temperature

    SciTech Connect

    Voter, A.F.; Doll, J.D.; Cohen, J.M.

    1989-02-01

    A method is presented for computing the classically exact, surface or bulk diffusion constant of a point defect at arbitrary temperature. The thermal diffusion constant is expressed using the squared jump length averaged over all possible final states to which the atom can jump. The rate constants that weight this sum are computed using transition state theory and molecular dynamics within a recently developed many-state dynamical corrections formalism. While these rate constants are valid only in the rare-event regime (i.e., at low temperature), it is shown that for a periodic lattice of equivalent binding sites, the resulting diffusion contants is valid at any temperature for which the lattice sites remain well defined. It is thus possible to compute classically exact surface or bulk diffusion constant for an arbitrary interatomic potential, without the time scale limitations of direct molecular dynamics.

  5. Equivalence of computer codes for calculation of coincidence summing correction factors - Part II.

    PubMed

    Vidmar, T; Camp, A; Hurtado, S; Jäderström, H; Kastlander, J; Lépy, M-C; Lutter, G; Ramebäck, H; Sima, O; Vargas, A

    2016-03-01

    The aim of this study was to check for equivalence of computer codes that are capable of performing calculations of true coincidence summing (TCS) correction factors. All calculations were performed for a set of well-defined detector parameters, sample parameters and decay scheme data. The studied geometry was a point source of (133)Ba positioned directly on the detector window of a low-energy (n-type) detector. Good agreement was established between the TCS correction factors computed by the different codes. PMID:26651169

  6. Reconstructing past sea surface temperatures: Correcting for diagenesis of bulk marine carbonate

    SciTech Connect

    Schrag, D.P.; DePaolo, D.J. |; Richter, F.M.

    1995-06-01

    A numerical model which describes oxygen isotope exchange during burial and recrystallization of deep-sea carbonate is used to obtain information on how sea surface temperatures have varied in the past by correcting measured {delta}{sup 18}O values of bulk carbonate for diagenetic overprinting. Comparison of bulk carbonate and planktonic foraminiferal {delta}{sup 18}O records from ODP site 677A indicates that the oxygen isotopic composition of bulk carbonate does reflect changes in sea surface temperature and {delta}{sup 18}O. At ODP Site 690, we calculate that diagenetic effects are small, and that both bulk carbonate and planktonic foraminiferal {delta}{sup 18}O records accurately reflect Paleogene warming of high latitude surface oceans, biased from diagenesis by no more than 1{degrees}C. The same is likely to be true for other high latitude sites where sedimentation rates are low. At DSDP sites 516 and 525, the effects of diagenesis are more significant. Measured {delta}{sup 18}O values of Eocene bulk carbonates are more than 2% lower at deeply buried site 516 than at site 525, consistent with the model prediction that the effects of diagenesis should be proportional to sedimentation rate. Model-corrections reconcile the differences in the data between the two sites; the resulting paleotemperature reconstruction indicates a 4{degrees}C cooling of mid-latitude surface oceans since the Eocene. We show that the data are consistent with constant equatorial sea surface temperatures through most of the Cenozoic, with the possible exception of the early Eocene, when slightly higher temperatures are indicated. We suggest that the lower equatorial sea surface temperatures for the Eocene and Oligocene reported in other oxygen isotope studies are artifacts of diagenetic recrystallization, and that it is impossible to reconstruct accurately equatorial sea surface temperatures without explicitly accounting for diagenetic overprinting.

  7. Correcting infrared satellite estimates of sea surface temperature for atmospheric water vapor attenuation

    NASA Technical Reports Server (NTRS)

    Emery, William J.; Yu, Yunyue; Wick, Gary A.; Schluessel, Peter; Reynolds, Richard W.

    1994-01-01

    A new satellite sea surface temperature (SST) algorithm is developed that uses nearly coincident measurements from the microwave special sensor microwave imager (SSM/I) to correct for atmospheric moisture attenuation of the infrared signal from the advanced very high resolution radiometer (AVHRR). This new SST algorithm is applied to AVHRR imagery from the South Pacific and Norwegian seas, which are then compared with simultaneous in situ (ship based) measurements of both skin and bulk SST. In addition, an SST algorithm using a quadratic product of the difference between the two AVHRR thermal infrared channels is compared with the in situ measurements. While the quadratic formulation provides a considerable improvement over the older cross product (CPSST) and multichannel (MCSST) algorithms, the SSM/I corrected SST (called the water vapor or WVSST) shows overall smaller errors when compared to both the skin and bulk in situ SST observations. Applied to individual AVHRR images, the WVSST reveals an SST difference pattern (CPSST-WVSST) similar in shape to the water vapor structure while the CPSST-quadratic SST difference appears unrelated in pattern to the nearly coincident water vapor pattern. An application of the WVSST to week-long composites of global area coverage (GAC) AVHRR data demonstrates again the manner in which the WVSST corrects the AVHRR for atmospheric moisture attenuation. By comparison the quadratic SST method underestimates the SST corrections in the lower latitudes and overestimates the SST in th e higher latitudes. Correlations between the AVHRR thermal channel differences and the SSM/I water vapor demonstrate the inability of the channel difference to represent water vapor in the midlatitude and high latitudes during summer. Compared against drifting buoy data the WVSST and the quadratic SST both exhibit the same general behavior with the relatively small differences with the buoy temperatures.

  8. Effects of signal corrections on measurements of temperature and OH concentrations using laser-induced fluorescence

    NASA Astrophysics Data System (ADS)

    Yin, Zhiyao; Carter, Campbell D.; Lempert, Walter R.

    2014-07-01

    Temperature and OH concentrations derived from OH laser-induced fluorescence (LIF) are known to be susceptible to effects such as collisional quenching, laser absorption, and fluorescence trapping. In this paper, a set of analytical and easy-to-implement methods is presented for treating these effects. The significance of these signal corrections on inferred temperature and absolute OH concentration is demonstrated in an atmospheric-pressure, near-stoichiometric CH4-air flame stabilized on a Hencken burner, for laser excitation of both the A2Σ+←X2Π (0,0) and (1,0) bands. It is found that the combined effect of laser attenuation and fluorescence trapping can cause considerable error in the OH number density and temperature if not accounted for, even with A-X(1,0) excitation. The validity of the assumptions used in signal correction (that the excited-state distribution is either thermalized or frozen) is examined using time-dependent modeling of the ro-vibronic states during and after laser excitation. These assumptions are shown to provide good bounding approximations for treating transition-dependent issues in OH LIF, especially for an unknown collisional environment, and it is noted that the proposed methods are generally applicable to LIF-based measurements.

  9. On depth and temperature biases in bathythermograph data: Development of a new correction scheme based on analysis of a global ocean database

    NASA Astrophysics Data System (ADS)

    Gouretski, Viktor; Reseghetti, Franco

    2010-06-01

    The World Ocean Database 2005 as of May 2009 is used to estimate temperature and sample depth biases of expendable (XBT) and mechanical (MBT) bathythermographs by comparing bathythermograph temperature profiles with more accurate bottle and conductivity/temperature/depth (CTD) data. It is shown that the application of depth corrections estimated earlier from side-by-side XBT/CTD inter-comparisons, without accounting for a pure thermal bias, leads to even larger disagreement with the CTD and bottle reference temperatures. Our calculations give evidence for a depth-variable XBT fall-rate correction with the manufacturer-derived depth being underestimated in the upper 200 m and overestimated below this depth. These results are in agreement with side-by-side inter-comparisons and direct fall-rate estimates. Correcting XBT sample depths by a multiplicative factor which is constant with depth does not allow an effective elimination of the total temperature bias throughout the whole water column. The analysis further suggests a dependence of the fall rate on the water temperature which was reported earlier in the literature. Comparison among different correction schemes implies a significant impact of systematic biases on the estimates of the global ocean heat content anomaly.

  10. Novel approach for the Monte Carlo calculation of free-air chamber correction factors.

    PubMed

    Mainegra-Hing, Ernesto; Reynaert, Nick; Kawrakow, Iwan

    2008-08-01

    A self-consistent approach for the Monte Carlo calculation of free-air chamber (FAC) correction factors needed to convert the chamber reading into the quantity air-kerma at the point of measurement is introduced, and its implementation in the new EGSnrc user code egs_fac is discussed. To validate the method, comparisons between computed and measured FAC correction factors for attenuation Ax, scatter (Ascat), and electron loss (Aeloss) are performed in the medium energy range where the experimental determination is believed to be accurate. The Monte Carlo calculations utilize a full simulation of the x-ray tube with BEAMnrc and a detailed model of the parallel-plate FAC. Excellent agreement between the computed Ascat and Aeloss and the measured values for these correction factors currently used in the National Research Council (NRC) of Canada primary FAC standard is observed. Our simulations also agree with previous Monte Carlo results for Ascat and Aeloss for the 135 and 250 kVp Consultative Committee for Ionizing Radiation reference beam qualities. The computed attenuation correction agrees with the measured Aatt within the stated uncertainties, although the authors' simulations demonstrate that the evacuated-tube technique employed at NRC to measure the attenuation correction slightly overestimates Aatt in the medium energy range. The newly introduced corrections for backscatter, beam geometry, and lack of charged particle equilibrium along the beam axis are found to be negligible. On the other hand, the correction for photons leaking through the FAC aperture, currently ignored in the NRC standard, is shown to be significant.

  11. Thermocouple error correction for measuring the flame temperature with determination of emissivity and heat transfer coefficient.

    PubMed

    Hindasageri, V; Vedula, R P; Prabhu, S V

    2013-02-01

    Temperature measurement by thermocouples is prone to errors due to conduction and radiation losses and therefore has to be corrected for precise measurement. The temperature dependent emissivity of the thermocouple wires is measured by the use of thermal infrared camera. The measured emissivities are found to be 20%-40% lower than the theoretical values predicted from theory of electromagnetism. A transient technique is employed for finding the heat transfer coefficients for the lead wire and the bead of the thermocouple. This method does not require the data of thermal properties and velocity of the burnt gases. The heat transfer coefficients obtained from the present method have an average deviation of 20% from the available heat transfer correlations in literature for non-reacting convective flow over cylinders and spheres. The parametric study of thermocouple error using the numerical code confirmed the existence of a minimum wire length beyond which the conduction loss is a constant minimal. Temperature of premixed methane-air flames stabilised on 16 mm diameter tube burner is measured by three B-type thermocouples of wire diameters: 0.15 mm, 0.30 mm, and 0.60 mm. The measurements are made at three distances from the burner tip (thermocouple tip to burner tip/burner diameter = 2, 4, and 6) at an equivalence ratio of 1 for the tube Reynolds number varying from 1000 to 2200. These measured flame temperatures are corrected by the present numerical procedure, the multi-element method, and the extrapolation method. The flame temperatures estimated by the two-element method and extrapolation method deviate from numerical results within 2.5% and 4%, respectively.

  12. Calculation of Coincidence Summing Correction Factors for an HPGe detector using GEANT4.

    PubMed

    Giubrone, G; Ortiz, J; Gallardo, S; Martorell, S; Bas, M C

    2016-07-01

    The aim of this paper was to calculate the True Coincidence Summing Correction Factors (TSCFs) for an HPGe coaxial detector in order to correct the summing effect as a result of the presence of (88)Y and (60)Co in a multigamma source used to obtain a calibration efficiency curve. Results were obtained for three volumetric sources using the Monte Carlo toolkit, GEANT4. The first part of this paper deals with modeling the detector in order to obtain a simulated full energy peak efficiency curve. A quantitative comparison between the measured and simulated values was made across the entire energy range under study. The True Summing Correction Factors were calculated for (88)Y and (60)Co using the full peak efficiencies obtained with GEANT4. This methodology was subsequently applied to (134)Cs, and presented a complex decay scheme. PMID:27085040

  13. The accuracy of climate models' simulated season lengths and the effectiveness of grid scale correction factors

    DOE PAGESBeta

    Winterhalter, Wade E.

    2011-09-01

    Global climate change is expected to impact biological populations through a variety of mechanisms including increases in the length of their growing season. Climate models are useful tools for predicting how season length might change in the future. However, the accuracy of these models tends to be rather low at regional geographic scales. Here, I determined the ability of several atmosphere and ocean general circulating models (AOGCMs) to accurately simulate historical season lengths for a temperate ectotherm across the continental United States. I also evaluated the effectiveness of regional-scale correction factors to improve the accuracy of these models. I foundmore » that both the accuracy of simulated season lengths and the effectiveness of the correction factors to improve the model's accuracy varied geographically and across models. These results suggest that regional specific correction factors do not always adequately remove potential discrepancies between simulated and historically observed environmental parameters. As such, an explicit evaluation of the correction factors' effectiveness should be included in future studies of global climate change's impact on biological populations.« less

  14. Finding of Correction Factor and Dimensional Error in Bio-AM Model by FDM Technique

    NASA Astrophysics Data System (ADS)

    Manmadhachary, Aiamunoori; Ravi Kumar, Yennam; Krishnanand, Lanka

    2016-06-01

    Additive Manufacturing (AM) is the swift manufacturing process, in which input data can be provided from various sources like 3-Dimensional (3D) Computer Aided Design (CAD), Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and 3D scanner data. From the CT/MRI data can be manufacture Biomedical Additive Manufacturing (Bio-AM) models. The Bio-AM model gives a better lead on preplanning of oral and maxillofacial surgery. However manufacturing of the accurate Bio-AM model is one of the unsolved problems. The current paper demonstrates error between the Standard Triangle Language (STL) model to Bio-AM model of dry mandible and found correction factor in Bio-AM model with Fused Deposition Modelling (FDM) technique. In the present work dry mandible CT images are acquired by CT scanner and supplied into a 3D CAD model in the form of STL model. Further the data is sent to FDM machine for fabrication of Bio-AM model. The difference between Bio-AM to STL model dimensions is considered as dimensional error and the ratio of STL to Bio-AM model dimensions considered as a correction factor. This correction factor helps to fabricate the AM model with accurate dimensions of the patient anatomy. These true dimensional Bio-AM models increasing the safety and accuracy in pre-planning of oral and maxillofacial surgery. The correction factor for Dimension SST 768 FDM AM machine is 1.003 and dimensional error is limited to 0.3 %.

  15. The accuracy of climate models' simulated season lengths and the effectiveness of grid scale correction factors

    SciTech Connect

    Winterhalter, Wade E.

    2011-09-01

    Global climate change is expected to impact biological populations through a variety of mechanisms including increases in the length of their growing season. Climate models are useful tools for predicting how season length might change in the future. However, the accuracy of these models tends to be rather low at regional geographic scales. Here, I determined the ability of several atmosphere and ocean general circulating models (AOGCMs) to accurately simulate historical season lengths for a temperate ectotherm across the continental United States. I also evaluated the effectiveness of regional-scale correction factors to improve the accuracy of these models. I found that both the accuracy of simulated season lengths and the effectiveness of the correction factors to improve the model's accuracy varied geographically and across models. These results suggest that regional specific correction factors do not always adequately remove potential discrepancies between simulated and historically observed environmental parameters. As such, an explicit evaluation of the correction factors' effectiveness should be included in future studies of global climate change's impact on biological populations.

  16. Simulation of a Wireless Power Transfer System for Electric Vehicles with Power Factor Correction

    SciTech Connect

    Pickelsimer, Michael C; Tolbert, Leon M; Ozpineci, Burak; Miller, John M

    2012-01-01

    Wireless power transfer has been a popular topic of recent research. Most research has been done to address the limitations of coil-to-coil efficiency. However, little has been done to address the problem associated with the low input power factor with which the systems operate. This paper details the steps taken to analyze a wireless power transfer system from the view of the power grid under a variety of loading conditions with and without power factor correction.

  17. Analysis, compensation, and correction of temperature effects on FBG strain sensors

    NASA Astrophysics Data System (ADS)

    Haber, T. C.; Ferguson, S.; Guthrie, D.; Graver, T. W.; Soller, B. J.; Mendez, Alexis

    2013-05-01

    One of the most common fiber optic sensor (FOS) types used are fiber Bragg gratings (FBG), and the most frequently measured parameter is strain. Hence, FBG strain sensors are one of the most prevalent FOS devices in use today in structural sensing and monitoring in civil engineering, aerospace, marine, oil and gas, composites and smart structure applications. However, since FBGs are simultaneously sensitive to both temperature and strain, it becomes essential to utilize sensors that are either fully temperature insensitive or, alternatively, properly temperature compensated to avoid erroneous measurements. In this paper, we introduce the concept of measured "total strain", which is inherent and unique to optical strain sensors. We review and analyze the temperature and strain sensitivities of FBG strain sensors and decompose the total measured strain into thermal and non-thermal components. We explore the differences between substrate CTE and System Thermal Response Coefficients, which govern the type and quality of thermal strain decomposition analysis. Finally, we present specific guidelines to achieve proper temperature-insensitive strain measurements by combining adequate installation, sensor packaging and data correction techniques.

  18. Atmospheric corrections of passive microwave data for estimating land surface temperature.

    PubMed

    Liu, Zeng-Lin; Wu, Hua; Tang, Bo-Hui; Qiu, Shi; Li, Zhao-Liang

    2013-07-01

    Quantitative analysis of the atmospheric effects on observations made by the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) has been performed. The differences between observed brightness temperatures at the top of the atmosphere and at the bottom of the atmosphere were analyzed using a database of simulated observations, which were configured to replicate AMSR-E data. The differences between observed brightness temperatures at the top of the atmosphere and land surface-emitted brightness temperatures were also computed. Quantitative results show that the atmosphere has different effects on brightness temperatures in different AMSR-E channels. Atmospheric effects can be neglected at 6.925 and 10.65 GHz, when the standard deviation is less than 1 K. However, at other frequencies and polarizations, atmospheric effects on observations should not be neglected. An atmospheric correction algorithm was developed at 18.7 GHz vertical polarization, based on the classic split-window algorithm used in thermal remote sensing. Land surface emission can be estimated with RMSE = 0.99 K using the proposed method. Using the known land surface emissivity, Land Surface Temperature (LST) can be retrieved. The RMSE of retrieved LST is 1.17 K using the simulated data.

  19. Estimation of absolute water surface temperature based on atmospherically corrected thermal infrared multispectral scanner digital data

    NASA Technical Reports Server (NTRS)

    Anderson, James E.

    1986-01-01

    Airborne remote sensing systems, as well as those on board Earth orbiting satellites, sample electromagnetic energy in discrete wavelength regions and convert the total energy sampled into data suitable for processing by digital computers. In general, however, the total amount of energy reaching a sensor system located at some distance from the target is composed not only of target related energy, but, in addition, contains a contribution originating from the atmosphere itself. Thus, some method must be devised for removing or at least minimizing the effects of the atmosphere. The LOWTRAN-6 Program was designed to estimate atmospheric transmittance and radiance for a given atmospheric path at moderate spectral resolution over an operational wavelength region from 0.25 to 28.5 microns. In order to compute the Thermal Infrared Multispectral Scanner (TIMS) digital values which were recorded in the absence of the atmosphere, the parameters derived from LOWTRAN-6 are used in a correction equation. The TIMS data were collected at 1:00 a.m. local time on November 21, 1983, over a recirculating cooling pond for a power plant in southeastern Mississippi. The TIMS data were analyzed before and after atmospheric corrections were applied using a band ratioing model to compute the absolute surface temperature of various points on the power plant cooling pond. The summarized results clearly demonstrate the desirability of applying atmospheric corrections.

  20. Method and apparatus for correcting eddy current signal voltage for temperature effects

    DOEpatents

    Kustra, Thomas A.; Caffarel, Alfred J.

    1990-01-01

    An apparatus and method for measuring physical characteristics of an electrically conductive material by the use of eddy-current techniques and compensating measurement errors caused by changes in temperature includes a switching arrangement connected between primary and reference coils of an eddy-current probe which allows the probe to be selectively connected between an eddy current output oscilloscope and a digital ohm-meter for measuring the resistances of the primary and reference coils substantially at the time of eddy current measurement. In this way, changes in resistance due to temperature effects can be completely taken into account in determining the true error in the eddy current measurement. The true error can consequently be converted into an equivalent eddy current measurement correction.

  1. LETTER: Optical thickness corrections to transient ECE temperature measurements in tokamak and stellarator plasmas

    NASA Astrophysics Data System (ADS)

    Peters, M.; Gorini, G.; Mantica, P.

    1995-07-01

    The conditions are examined under which optical thickness (τ) corrections to electron cyclotron emission (ECE) measurements of electron temperature (Te) can be neglected. By means of simple algebra it is demonstrated that for measurements of Te transients the ECE radiation temperature (Trad) can be directly interpreted as Te to a 15% inaccuracy for τ > 0.7. This method is a solution to the problem identified by Janicki in 1993, namely that to estimate the variation of Te relative to the time averaged Te (tilde Te/langleTerangle) by tilde Trad/langleTradrangle with the same accuracy requires τ > 3. This result implies that optical thickness effects have considerably less impact on the interpretation of ECE transients than suggested by Janicki and that they do not pose a serious problem to perturbative transport studies in small toroidal devices

  2. Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay; Zavodsky, Brad; Blackwell, William

    2014-01-01

    Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. This paper will describe the bias correction technique and results from forecasts evaluated by validation against a Total Precipitable Water (TPW) product from CIRA and against Global Forecast System (GFS) analyses.

  3. Radiative recoil corrections to hyperfine splitting: Polarization insertions in the electron factor

    SciTech Connect

    Eides, M. I.; Shelyuto, V. A.

    2010-01-15

    We consider three-loop radiative recoil corrections to hyperfine splitting in muonium due to insertions of the one-loop polarization operator in the electron factor. The contribution generated by electron polarization insertions is a cubic polynomial in the large logarithm of the electron-muon mass ratio. The leading logarithm cubed and logarithm squared terms are well known for some time. We calculate all single-logarithmic and nonlogarithmic radiative recoil corrections of the order {alpha}{sup 3}(m/M)E{sub F} generated by diagrams with the electron and muon polarization insertions.

  4. Correcting gene expression data when neither the unwanted variation nor the factor of interest are observed

    PubMed Central

    Jacob, Laurent; Gagnon-Bartsch, Johann A.; Speed, Terence P.

    2016-01-01

    When dealing with large scale gene expression studies, observations are commonly contaminated by sources of unwanted variation such as platforms or batches. Not taking this unwanted variation into account when analyzing the data can lead to spurious associations and to missing important signals. When the analysis is unsupervised, e.g. when the goal is to cluster the samples or to build a corrected version of the dataset—as opposed to the study of an observed factor of interest—taking unwanted variation into account can become a difficult task. The factors driving unwanted variation may be correlated with the unobserved factor of interest, so that correcting for the former can remove the latter if not done carefully. We show how negative control genes and replicate samples can be used to estimate unwanted variation in gene expression, and discuss how this information can be used to correct the expression data. The proposed methods are then evaluated on synthetic data and three gene expression datasets. They generally manage to remove unwanted variation without losing the signal of interest and compare favorably to state-of-the-art corrections. All proposed methods are implemented in the bioconductor package RUVnormalize. PMID:26286812

  5. Monte Carlo calculated correction factors for diodes and ion chambers in small photon fields.

    PubMed

    Czarnecki, D; Zink, K

    2013-04-21

    The application of small photon fields in modern radiotherapy requires the determination of total scatter factors Scp or field factors Ω(f(clin), f(msr))(Q(clin), Q(msr)) with high precision. Both quantities require the knowledge of the field-size-dependent and detector-dependent correction factor k(f(clin), f(msr))(Q(clin), Q(msr)). The aim of this study is the determination of the correction factor k(f(clin), f(msr))(Q(clin), Q(msr)) for different types of detectors in a clinical 6 MV photon beam of a Siemens KD linear accelerator. The EGSnrc Monte Carlo code was used to calculate the dose to water and the dose to different detectors to determine the field factor as well as the mentioned correction factor for different small square field sizes. Besides this, the mean water to air stopping power ratio as well as the ratio of the mean energy absorption coefficients for the relevant materials was calculated for different small field sizes. As the beam source, a Monte Carlo based model of a Siemens KD linear accelerator was used. The results show that in the case of ionization chambers the detector volume has the largest impact on the correction factor k(f(clin), f(msr))(Q(clin), Q(msr)); this perturbation may contribute up to 50% to the correction factor. Field-dependent changes in stopping-power ratios are negligible. The magnitude of k(f(clin), f(msr))(Q(clin), Q(msr)) is of the order of 1.2 at a field size of 1 × 1 cm(2) for the large volume ion chamber PTW31010 and is still in the range of 1.05-1.07 for the PinPoint chambers PTW31014 and PTW31016. For the diode detectors included in this study (PTW60016, PTW 60017), the correction factor deviates no more than 2% from unity in field sizes between 10 × 10 and 1 × 1 cm(2), but below this field size there is a steep decrease of k(f(clin), f(msr))(Q(clin), Q(msr)) below unity, i.e. a strong overestimation of dose. Besides the field size and detector dependence, the results reveal a clear dependence of the

  6. Juvenile Correctional Workers' Perceptions of Suicide Risk Factors and Mental Health Issues of Incarcerated Juveniles

    PubMed Central

    Penn, Joseph V.; Esposito, Christianne; Stein, L. A. R.; Lacher-Katz, Molly; Spirito, Anthony

    2009-01-01

    Correctional staff knowledge, attitudes, and perceptions of incarcerated juveniles' mental health needs, including suicide prevention, have not been studied empirically. This study measured juvenile correctional officers' knowledge and attitudes regarding suicide risk factors and mental health and substance abuse issues through administration of the Mental Health Knowledge and Attitude Test (MHKAT) before and after a staff training on suicide prevention. Seventy-six participants completed the pre- and post-training MHKAT. They demonstrated significant improvement in knowledge of and attitudes toward mental health treatment of incarcerated youth as reflected by higher post-training MHKAT scores. Findings suggest that correctional staff are receptive to increasing knowledge of critical mental health issues. Studies of the retention and implementation of this new knowledge by direct care staff over time and the optimal type and frequency of new staff training and continuing education are indicated. PMID:19809578

  7. A correction factor for the impact of cluster randomized sampling and its applications.

    PubMed

    Cousineau, Denis; Laurencelle, Louis

    2016-03-01

    Cluster randomized sampling is 1 method for sampling a population. It requires recruiting subgroups of participants from the population of interest (e.g., whole classes from schools) instead of individuals solicited independently. Here, we demonstrate how clusters affect the standard error of the mean. The presence of clusters influences 2 quantities, the variance of the means and the expected variance. Ignoring clustering produces spurious statistical significance and reduces statistical power when effect sizes are moderate to large. Here, we propose a correction factor. It can be used to estimate standard errors and confidence intervals of the mean under cluster randomized sampling. This correction factor is easy to integrate into regular tests of means and effect sizes. It can also be used to determine sample size needed to reach a prespecified power. Finally, this approach is an easy-to-use alternative to linear mixed modeling and hierarchical linear modeling when there are only 2 levels and no covariates. PMID:26651985

  8. Two-Photon Exchange Corrections to Precise Measurements of Proton Electroweak Form Factors

    NASA Astrophysics Data System (ADS)

    Afanasev, Andrei

    2004-10-01

    Higher-order QED effects play an important role for extracting information on proton form factors from electron scattering data. For the electric form factor of the proton, a previously neglected two-photon-exchange correction reconciles an observed discrepancy between Rosenbluth and polarization techniques [1]. We use a similar approach based on General Parton Distributions to compute additional radiative corrections to parity-violating electron scattering. [1] Y.C. Chen, A. Afanasev, S.J. Brodsky, C.E. Carlson and M. Vanderhaeghen, ``Partonic calculation of the two-photon exchange contribution to elastic electron proton scattering at large momentum transfer,`` arXiv:hep-ph/0403058, to appear in Phys.Rev.Lett.

  9. Temperature, gravity, and bolometric correction scales for non-supergiant OB stars

    NASA Astrophysics Data System (ADS)

    Nieva, M.-F.

    2013-02-01

    Context. Precise and accurate determinations of the atmospheric parameters effective temperature and surface gravity are mandatory to derive reliable chemical abundances in OB stars. Furthermore, fundamental parameters like distances, masses, radii, luminosities can also be derived from the temperature and gravity of the stars. Aims: Atmospheric parameters recently determined at high precision with several independent spectroscopic indicators in non-local thermodynamic equilibrium, with typical uncertainties of ~300 K for temperature and of ~0.05 dex for gravity, are employed to calibrate photometric relationships. This is in order to investigate whether a faster tool to estimate atmospheric parameters can be provided. Methods: Temperatures and gravities of 30 calibrators, i.e. well-studied OB main sequence to giant stars in the solar neighbourhood, are compared to reddening-independent quantities of the Johnson and Strömgren photometric systems, assuming normal reddening. In addition, we examine the spectral and luminosity classification of the star sample and compute bolometric corrections. Results: Calibrations of temperatures and gravities are proposed for various photometric indices and spectral types. Once the luminosity of the stars is well known, effective temperatures can be determined at a precision of ~400 K for luminosity classes III/IV and ~800 K for luminosity class V. Furthermore, surface gravities can reach internal uncertainties as low as ~0.08 dex when using our calibration to the Johnson Q-parameter. Similar precision is achieved for gravities derived from the β-index and the precision is lower for both atmospheric parameters when using the Strömgren indices [c1] and [u - b] . In contrast, external uncertainties are larger for the Johnson than for the Strömgren calibrations. Our uncertainties are smaller than typical differences among other methods in the literature, reaching values up to ± 2000 K for temperature and ± 0.25 dex for gravity

  10. A Passive Radio-Frequency Identification (RFID) Gas Sensor With Self-Correction Against Fluctuations of Ambient Temperature

    PubMed Central

    Potyrailo, Radislav A.; Surman, Cheryl

    2013-01-01

    Uncontrolled fluctuations of ambient temperature in the field typically greatly reduce accuracy of gas sensors. In this study, we developed an approach for the self-correction against fluctuations of ambient temperature of individual gas and vapor sensors. The main innovation of our work is in the temperature correction which is accomplished without the need for a separate uncoated reference sensor or a separate temperature sensor. Our sensors are resonant inductor-capacitor-resistor (LCR) transducers coated with sensing materials and operated as multivariable passive (battery-free) radio-frequency identification (RFID) sensors. Using our developed approach, we performed quantitation of an exemplary vapor over the temperature range from 25 to 40 °C. This technical solution will be attractive in numerous applications where temperature stabilization of a gas sensor or addition of auxiliary temperature or uncoated reference sensors is prohibitive. PMID:23956496

  11. Determination of ion recombination correction factors for a liquid ionization chamber in megavoltage photon beams

    NASA Astrophysics Data System (ADS)

    Choi, Sang Hyoun; Kim, Kum-Bae; Ji, Young Hoon; Kim, Chan Hyeong; Kim, Seonghoon; Huh, Hyun Do

    2015-05-01

    The aim of this study is to determine the ion recombination correction factor for a liquid ionization chamber in a high energy photon beam by using our experimental method. The ion recombination correction factors were determined by using our experimental method and were compared with theoretical and experimental methods proposed by using the theoretical method (Greening, Johansson) and the two-dose rate method in a cobalt beam and a high energy photon beam. In order to apply the liquid ionization chamber in a reference and small field dosimetry, we acquired the absorbed dose to water correction coefficient, the beam quality correction factor, and the influence quantities for the microLion chamber according to the TRS-398 protocol and applied the results to a high energy photon beam used in clinical fields. As a result, our experimental method for ion recombination in a cobalt beam agreed with the results from the heoretical method (Greening theory) better than it did with the results from the two-dose rate method. For high energy photon beams, the two-dose rate and our experimental methods were in good agreement, less than 2% deviation, while the theoretical general collection efficiency (Johansson et al.) deviated greatly from the experimental values. When we applied the factors for the absorbed dose to water measurement, the absorbed dose to water for the microLion chamber was in good agreement, within 1%, compared with the values for the PTW 30013 chamber in 6 and 10 MV Clinac iX and 6 and 15 MV Oncor impression. With these results, not only can the microLion ionization chamber be used to measure the absorbed dose to water in a reference condition, it can also be used to a the chamber for small, non-standard field dosimetry.

  12. Totem-Pole Power-Factor-Correction Converter under Critical-Conduction-Mode Interleaved Operation

    NASA Astrophysics Data System (ADS)

    Firmansyah, Eka; Tomioka, Satoshi; Abe, Seiya; Shoyama, Masahito; Ninomiya, Tamotsu

    This paper proposes a new power-factor-correction (PFC) topology, and explains its operation principle, its control mechanism, related application problems followed by experimental results. In this proposed topology, critical-conduction-mode (CRM) interleaved technique is applied to a bridgeless PFC in order to achieve high efficiency by combining benefits of each topology. This application is targeted toward low to middle power applications that normally employs continuous-conduction-mode boost converter.

  13. Factors Associated with Recidivism among Corrections-Based Treatment Participants in Rural and Urban Areas.

    PubMed

    Staton-Tindall, Michele; Harp, Kathi L H; Winston, Erin; Webster, J Matthew; Pangburn, Kevin

    2015-09-01

    The majority of corrections-based treatment outcome studies focus on individuals paroling to urban areas; thus there is a significant gap in the literature on outcomes, including recidivism, among individuals paroling to non-urban and rural communities. This study examines differences in factors associated with recidivism among former corrections-based treatment participants living in urban and rural communities following release. Analyses focused on secondary data collected from treatment participants in one southeastern state over a four year period between July 2006 and June 2010 including both baseline (treatment intake) and follow-up data (12-months post-release). Findings indicated that individuals in urban areas were 2.4 times more likely to recidivate than rural individuals. Other factors identified in separate rural and urban analyses also emerged as significant predictors in the overall model including age, gender, race, employment and drug use. Overall, these findings suggest that corrections-based treatment participants living in urban and rural areas following release may share similar risk factors for recidivism. However, rural areas may be protective for returning to custody despite the presence of some of these risks.

  14. Development of Tissue to Total Mass Correction Factor for Porites divaricata in Calcification Rate Studies

    NASA Astrophysics Data System (ADS)

    Cannone, T. C.; Kelly, S. K.; Foster, K.

    2013-05-01

    One anticipated result of ocean acidification is lower calcification rates of corals. Many studies currently use the buoyant weights of coral nubbins as a means of estimating skeletal weight during non-destructive experiments. The objectives of this study, conducted at the Little Cayman Research Centre, were twofold: (1) to determine whether the purple and yellow color variations of Porites divaricata had similar tissue mass to total mass ratios; and (2) to determine a correction factor for tissue mass based on the total coral mass. T-test comparisons indicated that the tissue to total mass ratios were statistically similar for purple and yellow cohorts, thus allowing them to be grouped together within a given sample population. Linear regression analysis provided a correction factor (r2 = 0.69) to estimate the tissue mass from the total mass, which may eliminate the need to remove tissue during studies and allow subsequent testing on the same nubbins or their return to the natural environment. Additional work is needed in the development of a correction factor for P. divaricata with a higher prediction accuracy.

  15. Next-to-leading-order corrections to exclusive processes in kT factorization

    NASA Astrophysics Data System (ADS)

    Nandi, Soumitra; Li, Hsiang-Nan

    2007-08-01

    We calculate next-to-leading-order corrections to exclusive processes in the kT factorization theorem, taking πγ*→γ as an example. Partons off shell by kT2 are considered in both the quark diagrams from full QCD and the effective diagrams for the pion wave function. The gauge dependences in the above two sets of diagrams cancel, when deriving the kT-dependent hard kernel as their difference. The gauge invariance of the hard kernel is then proven to all orders by induction. The light-cone singularities in the kT-dependent pion wave function are regularized by rotating the Wilson lines away from the light cone. This regularization introduces a factorization-scheme dependence into the hard kernel, which can be minimized in the standard way. Both the large double logarithms ln⁡2kT and ln⁡2x, x being a parton momentum fraction, arise from the loop correction to the virtual photon vertex, the former being absorbed into the pion wave function and organized by the kT resummation and the latter absorbed into a jet function and organized by the threshold resummation. The next-to-leading-order corrections are found to be only a few percent for πγ*→γ, if setting the factorization scale to the momentum transfer from the virtual photon.

  16. Factors Associated with Recidivism among Corrections-Based Treatment Participants in Rural and Urban Areas.

    PubMed

    Staton-Tindall, Michele; Harp, Kathi L H; Winston, Erin; Webster, J Matthew; Pangburn, Kevin

    2015-09-01

    The majority of corrections-based treatment outcome studies focus on individuals paroling to urban areas; thus there is a significant gap in the literature on outcomes, including recidivism, among individuals paroling to non-urban and rural communities. This study examines differences in factors associated with recidivism among former corrections-based treatment participants living in urban and rural communities following release. Analyses focused on secondary data collected from treatment participants in one southeastern state over a four year period between July 2006 and June 2010 including both baseline (treatment intake) and follow-up data (12-months post-release). Findings indicated that individuals in urban areas were 2.4 times more likely to recidivate than rural individuals. Other factors identified in separate rural and urban analyses also emerged as significant predictors in the overall model including age, gender, race, employment and drug use. Overall, these findings suggest that corrections-based treatment participants living in urban and rural areas following release may share similar risk factors for recidivism. However, rural areas may be protective for returning to custody despite the presence of some of these risks. PMID:25858761

  17. Revision and necessary correction of the long-term temperature series of Hohenpeissenberg, 1781-2006

    NASA Astrophysics Data System (ADS)

    Winkler, P.

    2009-10-01

    Having been in use at Hohenpeissenberg from 1781-1841, the Palatina thermometer was found to suffer from a positive bias of 0.5°R (or 0.63°C) as discovered by Lamont following a re-calibration made in 1842. The main reason was due to the composition of the glass used during the early instrumental period. Glass of this period tended to contract over many years due to thermal aftereffects, resulting in a gradual rise of the freezing point position in consequence of the shrinking bulb forming the mercury reservoir. While the problem of the gradually rising zero point was recognised relatively early, the reason was attributed to wrong causes. Around 1880, scientists recognised that the chemical composition of glass might be responsible for the drift of the zero point. New glass types were developed which were free from such effects. Although these facts became known, no correction was applied to the Hohenpeissenberg temperature series when in 1981, the complete 200-year series was published. Most probably this bias is also relevant for other stations, at least those of the network of the Societas Meteorologica Palatina that were supplied with thermometers manufactured in Mannheim. Another problem originates from the different observing times for the period 1879-1900, which were set to 0800, 1400 and 2000 hours instead of 0700, 1400 and 2100 hours before and afterwards. In addition, a new formula to calculate the daily mean was established resulting in the temperature being too low by 0.5°C in that period. The overall trend changes after application of the two necessary corrections. There remain two biases that cannot be quantified without a major detailed study being made: (1) At the start of the observations, the window of the observation room was always kept “open during dry weather”. It is not known how long this practice was remained in use. (2) Lamont also employed an easily melting glass to construct his thermometers which in use between 1841 and 1878. An

  18. Soil temperature effect in calculating attenuation and retardation factors.

    PubMed

    Paraiba, Lourival Costa; Spadotto, Claudio Aparecido

    2002-09-01

    The effect of annual variation of daily average soil temperature, at different depths, in calculating pesticides ranking indexes retardation factor and attenuation factor is presented. The retardation factor and attenuation factor are two site-specific pesticide numbers, frequently used as screening indicator indexes for pesticide groundwater contamination potential. Generally, in the calculation of these two factors are not included the soil temperature effect on the parameters involved in its calculation. It is well known that the soil temperature affects the pesticide degradation rate, water-air partition coefficient and water-soil partition coefficient. These three parameters are components of the retardation factor and attenuation factor and contribute to determine the pesticide behavior in the environment. The Arrhenius equation, van't Hoff equation and Clausius-Clapeyron equation are used in this work for estimating the soil temperature effect on the pesticide degradation rate, water-air partition coefficient and soil-water partition coefficient, respectively. These dependence relationships, between results of calculating attenuation and retardation factors and the soil temperature at different depths, can aid to understand the potential pesticide groundwater contamination on different weather conditions. Numerical results will be presented with pesticides atrazine and lindane in a soil profile with 20 degrees C constant temperature, minimum and maximum surface temperatures varying and spreading in the soil profile between -5 and 30 degrees C and between 15 and 45 degrees C.

  19. Review of Radition Quality Factors and Corrections to Dosimetry Data on the ISS

    NASA Astrophysics Data System (ADS)

    Cucinotta, F.; Wu, H.; Shavers, M.; George, K.

    Organ dose equivalents are precisely defined in terms of linear energy transfer (LET) spectra and the LET -dependent quality factor (Q). We discuss available methods for the determination of organ doses and Q's in low earth orbit including approaches to correct measurements performed on the International Space Station (ISS). For determining astronaut-specific organ doses all dosimetry data have limitations. Besides the differences due to the absence of the body-self shielding, other important corrections occur for each devise used on the ISS. Tissue equivalent proportional counters (TEPC's) have corrections due to the so - called wall effect and by the use of linear energy (y) as a surrogate for LET. Limitations in silicon detectors include those related to the finite energy - grid of the detector and the differences in nuclear secondaries produced in silicon in comparison to tissue. To understand variation in tissue specific dose, data from the Phantom Torso Experiment on ISS are considered. In contrast the use of biodosimetry includes the self-shielding and exact exposure history of the astronaut; however the LET response for chromosomal aberrations is distinct from the functional dependence of the quality factor on LET. Here we show that each approach can be corrected using theoretical models to reach a most likely value of the average quality factor for each mission. Values of Q are found to be dependent on tissue type and range from 1.4-1.6 and 3.0-4.0 for the trapped protons and galactic cosmic rays, respectively with the overall average dependent on the ISS altitude and the position in the solar cycle. Results for ISS Increments 1-4 are discussed.

  20. A new model for the estimation of time of death from vitreous potassium levels corrected for age and temperature.

    PubMed

    Zilg, B; Bernard, S; Alkass, K; Berg, S; Druid, H

    2015-09-01

    Analysis of potassium concentration in the vitreous fluid of the eye is frequently used by forensic pathologists to estimate the postmortem interval (PMI), particularly when other methods commonly used in the early phase of an investigation can no longer be applied. The postmortem rise in vitreous potassium has been recognized for several decades and is readily explained by a diffusion of potassium from surrounding cells into the vitreous fluid. However, there is no consensus regarding the mathematical equation that best describes this increase. The existing models assume a linear increase, but different slopes and starting points have been proposed. In this study, vitreous potassium levels, and a number of factors that may influence these levels, were examined in 462 cases with known postmortem intervals that ranged from 2h to 17 days. We found that the postmortem rise in potassium followed a non-linear curve and that decedent age and ambient temperature influenced the variability by 16% and 5%, respectively. A long duration of agony and a high alcohol level at the time of death contributed less than 1% variability, and evaluation of additional possible factors revealed no detectable impact on the rise of vitreous potassium. Two equations were subsequently generated, one that represents the best fit of the potassium concentrations alone, and a second that represents potassium concentrations with correction for decedent age and/or ambient temperature. The former was associated with narrow confidence intervals in the early postmortem phase, but the intervals gradually increased with longer PMIs. For the latter equation, the confidence intervals were reduced at all PMIs. Therefore, the model that best describes the observed postmortem rise in vitreous potassium levels includes potassium concentration, decedent age, and ambient temperature. Furthermore, the precision of these equations, particularly for long PMIs, is expected to gradually improve by adjusting the

  1. Quantum electrodynamic corrections to the g factor of helium P states

    NASA Astrophysics Data System (ADS)

    Puchalski, M.; Jentschura, U. D.

    2012-08-01

    The Landé g factor describes the response of an atomic energy level to an external perturbation by a uniform and constant magnetic field. In the case of many-electron systems, the leading term is given by the interaction μB(L⃗+2S⃗)·B⃗, where L⃗ and S⃗ are the orbital and spin angular momentum operators, respectively, summed over all electrons. For helium, a long-standing experimental-theoretical discrepancy for P states motivates a re-evaluation of the higher order terms which follow from relativistic quantum theory and quantum electrodynamics (QED). The tensor structure of relativistic corrections involves scalar, vector, and symmetric and antisymmetric tensor components. We perform a tensorial reduction of these operators in a Cartesian basis, using an approach which allows us to separate the internal atomic from the external degrees of freedom (magnetic field) right from the start of the calculation. The evaluation proceeds in a Cartesian basis of helium eigenstates, using a weighted sum over the magnetic projections. For the relativistic corrections, this leads to a verification of previous results obtained using the Wigner-Eckhart theorem. The same method, applied to the radiative correction (Bethe logarithm term) leads to a spin-dependent correction, which is different for singlet versus triplet P states. Theoretical predictions are given for singlet and triplet 2P and triplet 3P states and compared to experimental results where available.

  2. Artificial neural network based microwave precipitation estimation using scattering index and polarization corrected temperature

    NASA Astrophysics Data System (ADS)

    Mahesh, C.; Prakash, Satya; Sathiyamoorthy, V.; Gairola, R. M.

    2011-11-01

    An Artificial Neural Network (ANN) based technique is proposed for estimating precipitation over Indian land and oceanic regions [30° S - 40° N and 30° E - 120° E] using Scattering Index (SI) and Polarization Corrected Temperature (PCT) derived from Special Sensor Microwave Imager (SSM/I) measurements. This rainfall retrieval algorithm is designed to estimate rainfall using a combination of SSM/I and Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) measurements. For training the ANN, SI and PCT (which signify rain signatures in a better way) calculated from SSM/I brightness temperature are considered as inputs and Precipitation Radar (PR) rain rate as output. SI is computed using 19.35 GHz, 22.235 GHz and 85.5 GHz Vertical channels and PCT is computed using 85.5 GHz Vertical and Horizontal channels. Once the training is completed, the independent data sets (which were not included in the training) were used to test the performance of the network. Instantaneous precipitation estimates with independent test data sets are validated with PR surface rain rate measurements. The results are compared with precipitation estimated using power law based (i) global algorithm and (ii) regional algorithm. Overall results show that ANN based present algorithm shows better agreement with PR rain rate. This study is aimed at developing a more accurate operational rainfall retrieval algorithm for Indo-French Megha-Tropiques Microwave Analysis and Detection of Rain and Atmospheric Structures (MADRAS) radiometer.

  3. Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

    NASA Technical Reports Server (NTRS)

    Blakenship, Clay; Zavodsky, Bradley; Blackwell, William

    2014-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. Forecasts are against ERA reanalyses.

  4. Perturbative corrections to Λ b → Λ form factors from QCD light-cone sum rules

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Ming; Shen, Yue-Long

    2016-02-01

    We compute radiative corrections to Λ b → Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ b -baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ b -baryon correlation function is justified at leading power in Λ /m b , with the aid of the method of regions. Hard functions entering the factorization formulae are identical to the corresponding matching coefficients of heavy-to-light currents from QCD onto soft-collinear effective theory. The universal jet function from integrating out the hard-collinear fluctuations exhibits richer structures compared with the one involved in the factorization expressions of the vacuum-to- B-meson correlation function. Based upon the QCD resummation improved sum rules we observe that the perturbative corrections at {O}({α}_s) shift the Λ b → Λ from factors at large recoil significantly and the dominant contribution originates from the next-to-leading order jet function instead of the hard coefficient functions. Having at hand the sum rule predictions for the Λ b → Λ from factors we further investigate several decay observables in the electro-weak penguin Λ b → Λ ℓ + ℓ - transitions in the factorization limit (i.e., ignoring the "non-factorizable" hadronic effects which cannot be expressed in terms of the Λ b → Λ from factors), including the invariant mass distribution of the lepton pair, the forward-backward asymmetry in the dilepton system and the longitudinal polarization fraction of the leptonic sector.

  5. SU-E-T-469: A Practical Approach for the Determination of Small Field Output Factors Using Published Monte Carlo Derived Correction Factors

    SciTech Connect

    Calderon, E; Siergiej, D

    2014-06-01

    Purpose: Output factor determination for small fields (less than 20 mm) presents significant challenges due to ion chamber volume averaging and diode over-response. Measured output factor values between detectors are known to have large deviations as field sizes are decreased. No set standard to resolve this difference in measurement exists. We observed differences between measured output factors of up to 14% using two different detectors. Published Monte Carlo derived correction factors were used to address this challenge and decrease the output factor deviation between detectors. Methods: Output factors for Elekta's linac-based stereotactic cone system were measured using the EDGE detector (Sun Nuclear) and the A16 ion chamber (Standard Imaging). Measurements conditions were 100 cm SSD (source to surface distance) and 1.5 cm depth. Output factors were first normalized to a 10.4 cm × 10.4 cm field size using a daisy-chaining technique to minimize the dependence of field size on detector response. An equation expressing the relation between published Monte Carlo correction factors as a function of field size for each detector was derived. The measured output factors were then multiplied by the calculated correction factors. EBT3 gafchromic film dosimetry was used to independently validate the corrected output factors. Results: Without correction, the deviation in output factors between the EDGE and A16 detectors ranged from 1.3 to 14.8%, depending on cone size. After applying the calculated correction factors, this deviation fell to 0 to 3.4%. Output factors determined with film agree within 3.5% of the corrected output factors. Conclusion: We present a practical approach to applying published Monte Carlo derived correction factors to measured small field output factors for the EDGE and A16 detectors. Using this method, we were able to decrease the percent deviation between both detectors from 14.8% to 3.4% agreement.

  6. Spectral correction factors for conventional neutron dosemeters used in high-energy neutron environments.

    PubMed

    Lee, K W; Sheu, R J

    2015-04-01

    High-energy neutrons (>10 MeV) contribute substantially to the dose fraction but result in only a small or negligible response in most conventional moderated-type neutron detectors. Neutron dosemeters used for radiation protection purpose are commonly calibrated with (252)Cf neutron sources and are used in various workplace. A workplace-specific correction factor is suggested. In this study, the effect of the neutron spectrum on the accuracy of dose measurements was investigated. A set of neutron spectra representing various neutron environments was selected to study the dose responses of a series of Bonner spheres, including standard and extended-range spheres. By comparing (252)Cf-calibrated dose responses with reference values based on fluence-to-dose conversion coefficients, this paper presents recommendations for neutron field characterisation and appropriate correction factors for responses of conventional neutron dosemeters used in environments with high-energy neutrons. The correction depends on the estimated percentage of high-energy neutrons in the spectrum or the ratio between the measured responses of two Bonner spheres (the 4P6_8 extended-range sphere versus the 6″ standard sphere).

  7. Determination of small-field correction factors for cylindrical ionization chambers using a semiempirical method

    NASA Astrophysics Data System (ADS)

    Park, Kwangwoo; Bak, Jino; Park, Sungho; Choi, Wonhoon; Park, Suk Won

    2016-02-01

    A semiempirical method based on the averaging effect of the sensitive volumes of different air-filled ionization chambers (ICs) was employed to approximate the correction factors for beam quality produced from the difference in the sizes of the reference field and small fields. We measured the output factors using several cylindrical ICs and calculated the correction factors using a mathematical method similar to deconvolution; in the method, we modeled the variable and inhomogeneous energy fluence function within the chamber cavity. The parameters of the modeled function and the correction factors were determined by solving a developed system of equations as well as on the basis of the measurement data and the geometry of the chambers. Further, Monte Carlo (MC) computations were performed using the Monaco® treatment planning system to validate the proposed method. The determined correction factors (k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} ) were comparable to the values derived from the MC computations performed using Monaco®. For example, for a 6 MV photon beam and a field size of 1  ×  1 cm2, k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} was calculated to be 1.125 for a PTW 31010 chamber and 1.022 for a PTW 31016 chamber. On the other hand, the k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} values determined from the MC computations were 1.121 and 1.031, respectively; the difference between the proposed method and the MC computation is less than 2%. In addition, we determined the k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} values for PTW 30013, PTW 31010, PTW 31016, IBA FC23-C, and IBA CC13 chambers as well. We devised a method for determining k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} from both the measurement of the output factors and model-based mathematical computation. The proposed method can be useful in case the MC simulation would not be applicable for the clinical settings.

  8. An empirical method to correct for temperature-dependent variations in the overlap function of CHM15k ceilometers

    NASA Astrophysics Data System (ADS)

    Hervo, Maxime; Poltera, Yann; Haefele, Alexander

    2016-07-01

    Imperfections in a lidar's overlap function lead to artefacts in the background, range and overlap-corrected lidar signals. These artefacts can erroneously be interpreted as an aerosol gradient or, in extreme cases, as a cloud base leading to false cloud detection. A correct specification of the overlap function is hence crucial in the use of automatic elastic lidars (ceilometers) for the detection of the planetary boundary layer or of low cloud. In this study, an algorithm is presented to correct such artefacts. It is based on the assumption of a homogeneous boundary layer and a correct specification of the overlap function down to a minimum range, which must be situated within the boundary layer. The strength of the algorithm lies in a sophisticated quality-check scheme which allows the reliable identification of favourable atmospheric conditions. The algorithm was applied to 2 years of data from a CHM15k ceilometer from the company Lufft. Backscatter signals corrected for background, range and overlap were compared using the overlap function provided by the manufacturer and the one corrected with the presented algorithm. Differences between corrected and uncorrected signals reached up to 45 % in the first 300 m above ground. The amplitude of the correction turned out to be temperature dependent and was larger for higher temperatures. A linear model of the correction as a function of the instrument's internal temperature was derived from the experimental data. Case studies and a statistical analysis of the strongest gradient derived from corrected signals reveal that the temperature model is capable of a high-quality correction of overlap artefacts, in particular those due to diurnal variations. The presented correction method has the potential to significantly improve the detection of the boundary layer with gradient-based methods because it removes false candidates and hence simplifies the attribution of the detected gradients to the planetary boundary layer. A

  9. Study of the replacement correction factors for ionization chamber dosimetry by Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Wang, Lilie

    In ionization chamber radiation dosimetry, the introduction of the ion chamber into medium will unavoidably distort the radiation field near the chamber because the chamber cavity material (air) is different from the medium. A replacement correction factor, Prepl was introduced in order to correct the chamber readings to give an accurate radiation dose in the medium without the presence of the chamber. Generally it is very hard to measure the values of Prepl since they are intertwined with the chamber wall effect. In addition, the P repl values always come together with the stopping-power ratio of the two media involved. This makes the problem of determining the P repl values even more complicated. Monte Carlo simulation is an ideal method to investigate the replacement correction factors. In this study, four different methods of calculating the values of Prepl by Monte Carlo simulation are discussed. Two of the methods are designated as 'direct' methods in the sense that the evaluation of the stopping-power ratio is not necessary. The systematic uncertainties of the two direct methods are estimated to be about 0.1-0.2% which comes from the ambiguous definition of the energy cutoff Delta used in the Spencer-Attix cavity theory. The two direct methods are used to calculate the values of P repl for both plane-parallel chambers and cylindrical thimble chambers in either electron beams or photon beams. The calculation results are compared to measurements. For electron beams, good agreements are obtained. For thimble chambers in photon beams, significant discrepancies are observed between calculations and measurements. The experiments are thus investigated and the procedures are simulated by the Monte Carlo method. It is found that the interpretation of the measured data as the replacement correction factors in dosimetry protocols are not correct. In applying the calculation to the BIPM graphite chamber in a 60Co beam, the calculated values of P repl differ from those

  10. Low-temperature ignition delay for hydrogen-air mixtures in light of a reaction mechanism with quantum correction

    NASA Astrophysics Data System (ADS)

    Medvedev, S. P.; Agafonov, G. L.; Khomik, S. V.

    2016-09-01

    A reaction mechanism with quantum correction is used to model low-temperature/high-pressure autoignition of lean hydrogen-air mixtures. This approach provides a good approximation for experimental data on autoignition delay and the low activation energy observed in experiments. Calculated results demonstrate that ignition delay time is inversely proportional to pressure, squared. The proposed scaling reduces spread in experimental data. The application of a quantum correction to hydrogen oxidation provides a basis for developing a general reaction mechanism that can be used to predict the autoignition behavior of hydrogen over an entire temperature/pressure range relevant to rocket engine conditions.

  11. Calculation of correction factors for ionization chamber measurements with small fields in low-density media.

    PubMed

    Pisaturo, O; Pachoud, M; Bochud, F O; Moeckli, R

    2012-07-21

    The quantity of interest for high-energy photon beam therapy recommended by most dosimetric protocols is the absorbed dose to water. Thus, ionization chambers are calibrated in absorbed dose to water, which is the same quantity as what is calculated by most treatment planning systems (TPS). However, when measurements are performed in a low-density medium, the presence of the ionization chamber generates a perturbation at the level of the secondary particle range. Therefore, the measured quantity is close to the absorbed dose to a volume of water equivalent to the chamber volume. This quantity is not equivalent to the dose calculated by a TPS, which is the absorbed dose to an infinitesimally small volume of water. This phenomenon can lead to an overestimation of the absorbed dose measured with an ionization chamber of up to 40% in extreme cases. In this paper, we propose a method to calculate correction factors based on the Monte Carlo simulations. These correction factors are obtained by the ratio of the absorbed dose to water in a low-density medium □D(w,Q,V1)(low) averaged over a scoring volume V₁ for a geometry where V₁ is filled with the low-density medium and the absorbed dose to water □D(w,QV2)(low) averaged over a volume V₂ for a geometry where V₂ is filled with water. In the Monte Carlo simulations, □D(w,QV2)(low) is obtained by replacing the volume of the ionization chamber by an equivalent volume of water, according to the definition of the absorbed dose to water. The method is validated in two different configurations which allowed us to study the behavior of this correction factor as a function of depth in phantom, photon beam energy, phantom density and field size.

  12. Correction factors for low perturbation in vivo diodes used in the determination of entrance doses in high energy photon beams

    SciTech Connect

    Roberts, Ralph; Philp, Amanda

    2008-01-15

    Purpose--Low perturbation diodes, with thin buildup caps, can be used to reduce perturbations to the delivered dose. The literature states that additional correction factors are required for low perturbation diodes, however, there are few reported studies into their use. This report measured the dose perturbations and correction factors for diodes with varying buildup cap thicknesses. Methods and materials--Scanditronix EDP15, EDD5, and EDD2 diodes were investigated. Dose perturbations and correction factors for field size, source-surface distance (SSD), obliquity, and wedge were measured in megavoltage photon beams. Results--EDP15 produces a 6% dose perturbation. EDD5 produces a perturbation between 1% and 2%. EDD2 perturbation is negligible. The variation of correction factors for the full buildup EDP15 diode is small and consistent with the literature. The low perturbation diode EDD2 has large correction factors. The field size correction factor varies from 1.38 to 0.87 for 10 MV. The SSD correction factor varies from 0.92 to 1.09 for 10 MV. At the maximum angle measured, the obliquity correction factor is 0.73 for 10 MV. Intermediate results were observed for the EDD5 diode. Conclusions--It is expected that it will be very difficult to achieve accurate in vivo dosimetry using the EDD2 diode. The EDD5 diode may represent a reasonable compromise between EDD2 and the full buildup EDP15. The EDD5 dose perturbation is small and the correction factors are not as large as for EDD2, so accurate in vivo dosimetry may be possible as long as the obliquity is below 45 degrees.

  13. Shutterless solution for simultaneous focal plane array temperature estimation and nonuniformity correction in uncooled long-wave infrared camera.

    PubMed

    Cao, Yanpeng; Tisse, Christel-Loic

    2013-09-01

    In uncooled long-wave infrared (LWIR) microbolometer imaging systems, temperature fluctuations of the focal plane array (FPA) result in thermal drift and spatial nonuniformity. In this paper, we present a novel approach based on single-image processing to simultaneously estimate temperature variances of FPAs and compensate the resulting temperature-dependent nonuniformity. Through well-controlled thermal calibrations, empirical behavioral models are derived to characterize the relationship between the responses of microbolometer and FPA temperature variations. Then, under the assumption that strong dependency exists between spatially adjacent pixels, we estimate the optimal FPA temperature so as to minimize the global intensity variance across the entire thermal infrared image. We make use of the estimated FPA temperature to infer an appropriate nonuniformity correction (NUC) profile. The performance and robustness of the proposed temperature-adaptive NUC method are evaluated on realistic IR images obtained by a 640 × 512 pixels uncooled LWIR microbolometer imaging system operating in a significantly changed temperature environment.

  14. Bidirectional scattering distribution function measurements from volume diffusers: correction factors and associated uncertainties.

    PubMed

    Germer, Thomas A

    2016-09-01

    We consider the effect of volume diffusion on measurements of the bidirectional scattering distribution function when a finite distance is used for the solid angle defining aperture. We derive expressions for correction factors that can be used when the reduced scattering coefficients and the index of refraction are known. When these quantities are not known, the expressions can be used to guide the assessment of measurement uncertainty. We find that some measurement geometries reduce the effect of volume diffusion compared to their reciprocal geometries. PMID:27607273

  15. Reliability of IGBT in a STATCOM for Harmonic Compensation and Power Factor Correction

    SciTech Connect

    Gopi Reddy, Lakshmi Reddy; Tolbert, Leon M; Ozpineci, Burak; Xu, Yan; Rizy, D Tom

    2012-01-01

    With smart grid integration, there is a need to characterize reliability of a power system by including reliability of power semiconductors in grid related applications. In this paper, the reliability of IGBTs in a STATCOM application is presented for two different applications, power factor correction and harmonic elimination. The STATCOM model is developed in EMTP, and analytical equations for average conduction losses in an IGBT and a diode are derived and compared with experimental data. A commonly used reliability model is used to predict reliability of IGBT.

  16. Finite temperature corrections and embedded strings in noncommutative geometry and the standard model with neutrino mixing

    SciTech Connect

    Martins, R. A.

    2007-08-15

    The recent extension of the standard model to include massive neutrinos in the framework of noncommutative geometry and the spectral action principle involves new scalar fields and their interactions with the usual complex scalar doublet. After ensuring that they bring no unphysical consequences, we address the question of how these fields affect the physics predicted in the Weinberg-Salam theory, particularly in the context of the electroweak phase transition. Applying the Dolan-Jackiw procedure, we calculate the finite temperature corrections, and find that the phase transition is first order. The new scalar interactions significantly improve the stability of the electroweak Z string, through the 'bag' phenomenon described by Vachaspati and Watkins ['Bound states can stabilize electroweak strings', Phys. Lett. B 318, 163-168 (1993)]. (Recently, cosmic strings have climbed back into interest due to a new evidence.) Sourced by static embedded strings, an internal space analogy of Cartan's torsion is drawn, and a possible Higgs-force-like 'gravitational' effect of this nonpropagating torsion on the fermion masses is described. We also check that the field generating the Majorana mass for the {nu}{sub R} is nonzero in the physical vacuum.

  17. Sensitivity and specificity of WAIS-III/WMS-III demographically corrected factor scores in neuropsychological assessment.

    PubMed

    Taylor, M J; Heaton, R K

    2001-11-01

    This study explored the neurodiagnostic utility of 6 factor scores identified by recent exploratory and confirmatory factor analyses of the WAIS-III and WMS-III: Verbal Comprehension, Perceptual Organization, Processing Speed, Working Memory, Auditory Memory and Visual Memory. Factor scores were corrected for age. education, sex and ethnicity to minimize their influences on diagnostic accuracy. Cut-offs at 1, 1.5 and 2 standard deviations (SDs) below the standardization sample mean were applied to data from the overlapping test normative samples (N = 1073) and 6 clinical samples described in the WAIS-III/WMS-III Technical Manual (N = 126). The analyses suggest that a I SD cut-off yields the most balanced levels of sensitivity and specificity; more strict (1.5 or 2 SD) cut-offs generally result in trading modest gains in specificity for larger losses in sensitivity. Finally, using combinations of WAIS-III/WMS-III factors together as test batteries, we explored the sensitivity and specificity implications of varying diagnostic decision rules (e.g.,1 vs. 2 impaired factors = "impairment"). For most of the disorders considered here, even a small (e.g., 3 factor) WAIS-III/WMS-III battery provides quite good overall diagnostic accuracy.

  18. BENDING RADIOGRAPHS AS A PREDICTIVE FACTOR IN SURGICAL CORRECTION OF ADOLESCENT IDIOPATHIC SCOLIOSIS

    PubMed Central

    Gotfryd, Alberto Ofenhejm; Franzin, Fernando José; Poletto, Patrícia Rios; de Laura, Alexandre Spertini; da Silva, Luis Carlos Ferreira

    2015-01-01

    Objective: To evaluate the use of x-rays in dorsal decubitus, as a predictive factor for surgical correction of the main thoracic curve using pedicle screws, on patients with idiopathic adolescent scoliosis. Method: Twenty patients with idiopathic adolescent scoliosis of Lenke types 1A and 1B who were operated using a technique only involving pedicle screws by means of the posterior route were evaluated clinically and radiographically. The curve flexibility was calculated by means of active supine lateral oblique radiographs. The postoperative values for the main thoracic curve were included in a mathematical equation proposed by Cheung et al., with the aim of predicting the expected angular result from the surgical correction. The difference between the expected and actual postoperative results was then investigated regarding its statistical significance. Results: There was statistical significance for all the cases studied, between the values predicted before the operation and the radiographic findings immediately after the operation (p < 0.005). Conclusions: It is possible to predict the percentage surgical correction of the main thoracic curve that will be achieved using pedicle screws in patients with idiopathic adolescent scoliosis of Lenke types 1A and 1B, by means of preoperative supine oblique radiographs. PMID:27027056

  19. The correction factors for sucrose gap measurements and their practical applications.

    PubMed Central

    Jirounek, P; Jones, G J; Burckhardt, C W; Straub, R W

    1981-01-01

    The distribution of extracellular and intracellular potential in the sucrose gap apparatus, previously established for a single fiber using the cable equations for a core conductor model (Jirounek and Straub, Biophys. J., 11:1, 1971), is obtained for a multifiber preparation. The exact equation is derived relating the true membrane potential change to the measured potential differences across the sucrose gap, the junction potentials between sucrose and physiological solution, the membrane potential in the sucrose region, and the electrical parameters of the preparation in each region of the sucrose gap. The extracellular potential distribution has been measured using a modified sucrose gap apparatus for the frog sciatic nerve and the rabbit vagus nerve. The results indicate a hyperpolarization of the preparations in the sucrose region, of 60--75 mV. The hyperpolarization is independent of the presence of junction potentials. The calculation of the correction terms in the equation relating the actual to the measured potential change is illustrated for the case of complete depolarization by KC1 on one side of the sucrose gap. The correction terms in the equation are given for various experimental conditions, and a number of nomographic charts are presented, by means of which the correction factors can be rapidly evaluated. PMID:6974012

  20. Factors Associated with Correct and Consistent Insecticide Treated Curtain Use in Iquitos, Peru.

    PubMed

    Paz-Soldan, Valerie A; Bauer, Karin; Morrison, Amy C; Cordova Lopez, Jhonny J; Izumi, Kiyohiko; Scott, Thomas W; Elder, John P; Alexander, Neal; Halsey, Eric S; McCall, Philip J; Lenhart, Audrey

    2016-03-01

    Dengue is an arthropod-borne virus of great public health importance, and control of its mosquito vectors is currently the only available method for prevention. Previous research has suggested that insecticide treated curtains (ITCs) can lower dengue vector infestations in houses. This observational study investigated individual and household-level socio-demographic factors associated with correct and consistent use of ITCs in Iquitos, Peru. A baseline knowledge, attitudes, and practices (KAP) survey was administered to 1,333 study participants, and ITCs were then distributed to 593 households as part of a cluster-randomized trial. Follow up KAP surveys and ITC-monitoring checklists were conducted at 9, 18, and 27 months post-ITC distribution. At 9 months post-distribution, almost 70% of ITCs were hanging properly (e.g. hanging fully extended or tied up), particularly those hung on walls compared to other locations. Proper ITC hanging dropped at 18 months to 45.7%. The odds of hanging ITCs correctly and consistently were significantly greater among those participants who were housewives, knew three or more correct symptoms of dengue and at least one correct treatment for dengue, knew a relative or close friend who had had dengue, had children sleeping under a mosquito net, or perceived a change in the amount of mosquitoes in the home. Additionally, the odds of recommending ITCs in the future were significantly greater among those who perceived a change in the amount of mosquitoes in the home (e.g. perceived the ITCs to be effective). Despite various challenges associated with the sustained effectiveness of the selected ITCs, almost half of the ITCs were still hanging at 18 months, suggesting a feasible vector control strategy for sustained community use. PMID:26967157

  1. Factors Associated with Correct and Consistent Insecticide Treated Curtain Use in Iquitos, Peru

    PubMed Central

    Scott, Thomas W.; Elder, John P.; Alexander, Neal; Halsey, Eric S.; McCall, Philip J.

    2016-01-01

    Dengue is an arthropod-borne virus of great public health importance, and control of its mosquito vectors is currently the only available method for prevention. Previous research has suggested that insecticide treated curtains (ITCs) can lower dengue vector infestations in houses. This observational study investigated individual and household-level socio-demographic factors associated with correct and consistent use of ITCs in Iquitos, Peru. A baseline knowledge, attitudes, and practices (KAP) survey was administered to 1,333 study participants, and ITCs were then distributed to 593 households as part of a cluster-randomized trial. Follow up KAP surveys and ITC-monitoring checklists were conducted at 9, 18, and 27 months post-ITC distribution. At 9 months post-distribution, almost 70% of ITCs were hanging properly (e.g. hanging fully extended or tied up), particularly those hung on walls compared to other locations. Proper ITC hanging dropped at 18 months to 45.7%. The odds of hanging ITCs correctly and consistently were significantly greater among those participants who were housewives, knew three or more correct symptoms of dengue and at least one correct treatment for dengue, knew a relative or close friend who had had dengue, had children sleeping under a mosquito net, or perceived a change in the amount of mosquitoes in the home. Additionally, the odds of recommending ITCs in the future were significantly greater among those who perceived a change in the amount of mosquitoes in the home (e.g. perceived the ITCs to be effective). Despite various challenges associated with the sustained effectiveness of the selected ITCs, almost half of the ITCs were still hanging at 18 months, suggesting a feasible vector control strategy for sustained community use. PMID:26967157

  2. Factors Associated with Correct and Consistent Insecticide Treated Curtain Use in Iquitos, Peru.

    PubMed

    Paz-Soldan, Valerie A; Bauer, Karin; Morrison, Amy C; Cordova Lopez, Jhonny J; Izumi, Kiyohiko; Scott, Thomas W; Elder, John P; Alexander, Neal; Halsey, Eric S; McCall, Philip J; Lenhart, Audrey

    2016-03-01

    Dengue is an arthropod-borne virus of great public health importance, and control of its mosquito vectors is currently the only available method for prevention. Previous research has suggested that insecticide treated curtains (ITCs) can lower dengue vector infestations in houses. This observational study investigated individual and household-level socio-demographic factors associated with correct and consistent use of ITCs in Iquitos, Peru. A baseline knowledge, attitudes, and practices (KAP) survey was administered to 1,333 study participants, and ITCs were then distributed to 593 households as part of a cluster-randomized trial. Follow up KAP surveys and ITC-monitoring checklists were conducted at 9, 18, and 27 months post-ITC distribution. At 9 months post-distribution, almost 70% of ITCs were hanging properly (e.g. hanging fully extended or tied up), particularly those hung on walls compared to other locations. Proper ITC hanging dropped at 18 months to 45.7%. The odds of hanging ITCs correctly and consistently were significantly greater among those participants who were housewives, knew three or more correct symptoms of dengue and at least one correct treatment for dengue, knew a relative or close friend who had had dengue, had children sleeping under a mosquito net, or perceived a change in the amount of mosquitoes in the home. Additionally, the odds of recommending ITCs in the future were significantly greater among those who perceived a change in the amount of mosquitoes in the home (e.g. perceived the ITCs to be effective). Despite various challenges associated with the sustained effectiveness of the selected ITCs, almost half of the ITCs were still hanging at 18 months, suggesting a feasible vector control strategy for sustained community use.

  3. THE CALCULATION OF BURNABLE POISON CORRECTION FACTORS FOR PWR FRESH FUEL ACTIVE COLLAR MEASUREMENTS

    SciTech Connect

    Croft, Stephen; Favalli, Andrea; Swinhoe, Martyn T.

    2012-06-19

    Verification of commercial low enriched uranium light water reactor fuel takes place at the fuel fabrication facility as part of the overall international nuclear safeguards solution to the civilian use of nuclear technology. The fissile mass per unit length is determined nondestructively by active neutron coincidence counting using a neutron collar. A collar comprises four slabs of high density polyethylene that surround the assembly. Three of the slabs contain {sup 3}He filled proportional counters to detect time correlated fission neutrons induced by an AmLi source placed in the fourth slab. Historically, the response of a particular collar design to a particular fuel assembly type has been established by careful cross-calibration to experimental absolute calibrations. Traceability exists to sources and materials held at Los Alamos National Laboratory for over 35 years. This simple yet powerful approach has ensured consistency of application. Since the 1980's there has been a steady improvement in fuel performance. The trend has been to higher burn up. This requires the use of both higher initial enrichment and greater concentrations of burnable poisons. The original analytical relationships to correct for varying fuel composition are consequently being challenged because the experimental basis for them made use of fuels of lower enrichment and lower poison content than is in use today and is envisioned for use in the near term. Thus a reassessment of the correction factors is needed. Experimental reassessment is expensive and time consuming given the great variation between fuel assemblies in circulation. Fortunately current modeling methods enable relative response functions to be calculated with high accuracy. Hence modeling provides a more convenient and cost effective means to derive correction factors which are fit for purpose with confidence. In this work we use the Monte Carlo code MCNPX with neutron coincidence tallies to calculate the influence of Gd

  4. QCD corrections to B → π form factors from light-cone sum rules

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Ming; Shen, Yue-Long

    2015-09-01

    We compute perturbative corrections to B → π form factors from QCD light-cone sum rules with B-meson distribution amplitudes. Applying the method of regions we demonstrate factorization of the vacuum-to-B-meson correlation function defined with an interpolating current for pion, at one-loop level, explicitly in the heavy quark limit. The short-distance functions in the factorization formulae of the correlation function involves both hard and hard-collinear scales; and these functions can be further factorized into hard coefficients by integrating out the hard fluctuations and jet functions encoding the hard-collinear information. Resummation of large logarithms in the short-distance functions is then achieved via the standard renormalization-group approach. We further show that structures of the factorization formulae for fBπ+ (q2) and fBπ0 (q2) at large hadronic recoil from QCD light-cone sum rules match that derived in QCD factorization. In particular, we perform an exploratory phenomenological analysis of B → π form factors, paying attention to various sources of perturbative and systematic uncertainties, and extract |Vub | = (3.05-0.38+0.54|th. ± 0.09|exp.) ×10-3 with the inverse moment of the B-meson distribution amplitude ϕB+ (ω) determined by reproducing fBπ+ (q2 = 0) obtained from the light-cone sum rules with π distribution amplitudes. Furthermore, we present the invariant-mass distributions of the lepton pair for B → πℓνℓ (ℓ = μ, τ) in the whole kinematic region. Finally, we discuss non-valence Fock state contributions to the B → π form factors fBπ+ (q2) and fBπ0 (q2) in brief.

  5. Physics-Based Correction of Inhomogeneities in Temperature Series: Model Transferability Testing and Comparison to Statistical Approaches

    NASA Astrophysics Data System (ADS)

    Auchmann, Renate; Brönnimann, Stefan; Croci-Maspoli, Mischa

    2016-04-01

    For the correction of inhomogeneities in sub-daily temperature series, Auchmann and Brönnimann (2012) developed a physics-based model for one specific type of break, i.e. the transition from a Wild screen to a Stevenson screen at one specific station in Basel, Switzerland. The model is based solely on physical considerations, no relationships of the covariates to the differences between the parallel measurements have been investigated. The physics-based model requires detailed information on the screen geometry, the location, and includes a variety of covariates in the model. The model is mainly based on correcting the radiation error, including a modification by ambient wind. In this study we test the application of the model to another station, Zurich, experiencing the same type of transition. Furthermore we compare the performance of the physics based correction to purely statistical correction approaches (constant correction, correcting for annual cycle using spline). In Zurich the Wild screen was replaced in 1954 by the Stevenson screen, from 1954-1960 parallel temperature measurements in both screens were taken, which will be used to assess the performance of the applied corrections. For Zurich the required model input is available (i.e. three times daily observations of wind, cloud cover, pressure and humidity measurements, local times of sunset and sunrise). However, a large number of stations do not measure these additional input data required for the model, which hampers the transferability and applicability of the model to other stations. Hence, we test possible simplifications and generalizations of the model to make it more easily applicable to stations with the same type of inhomogeneity. In a last step we test whether other types of transitions (e.g., from a Stevenson screen to an automated weather system) can be corrected using the principle of a physics-based approach.

  6. Experimental setup for the determination of the correction factors of the neutron doseratemeters in fast neutron fields

    SciTech Connect

    Iliescu, Elena; Bercea, Sorin; Dudu, Dorin; Celarel, Aurelia

    2013-12-16

    The use of the U-120 Cyclotron of the IFIN-HH allowed to perform a testing bench with fast neutrons in order to determine the correction factors of the doseratemeters dedicated to neutron measurement. This paper deals with researchers performed in order to develop the irradiation facility testing the fast neutrons flux generated at the Cyclotron. This facility is presented, together with the results obtain in determining the correction factor for a doseratemeter dedicated to the neutron dose equivalent rate measurement.

  7. Determination of the thermodynamic correction factor of fluids confined in nano-metric slit pores from molecular simulation

    SciTech Connect

    Collell, Julien; Galliero, Guillaume

    2014-05-21

    The multi-component diffusive mass transport is generally quantified by means of the Maxwell-Stefan diffusion coefficients when using molecular simulations. These coefficients can be related to the Fick diffusion coefficients using the thermodynamic correction factor matrix, which requires to run several simulations to estimate all the elements of the matrix. In a recent work, Schnell et al. [“Thermodynamics of small systems embedded in a reservoir: A detailed analysis of finite size effects,” Mol. Phys. 110, 1069–1079 (2012)] developed an approach to determine the full matrix of thermodynamic factors from a single simulation in bulk. This approach relies on finite size effects of small systems on the density fluctuations. We present here an extension of their work for inhomogeneous Lennard Jones fluids confined in slit pores. We first verified this extension by cross validating the results obtained from this approach with the results obtained from the simulated adsorption isotherms, which allows to determine the thermodynamic factor in porous medium. We then studied the effects of the pore width (from 1 to 15 molecular sizes), of the solid-fluid interaction potential (Lennard Jones 9-3, hard wall potential) and of the reduced fluid density (from 0.1 to 0.7 at a reduced temperature T* = 2) on the thermodynamic factor. The deviation of the thermodynamic factor compared to its equivalent bulk value decreases when increasing the pore width and becomes insignificant for reduced pore width above 15. We also found that the thermodynamic factor is sensitive to the magnitude of the fluid-fluid and solid-fluid interactions, which softens or exacerbates the density fluctuations.

  8. Determination of the thermodynamic correction factor of fluids confined in nano-metric slit pores from molecular simulation

    NASA Astrophysics Data System (ADS)

    Collell, Julien; Galliero, Guillaume

    2014-05-01

    The multi-component diffusive mass transport is generally quantified by means of the Maxwell-Stefan diffusion coefficients when using molecular simulations. These coefficients can be related to the Fick diffusion coefficients using the thermodynamic correction factor matrix, which requires to run several simulations to estimate all the elements of the matrix. In a recent work, Schnell et al. ["Thermodynamics of small systems embedded in a reservoir: A detailed analysis of finite size effects," Mol. Phys. 110, 1069-1079 (2012)] developed an approach to determine the full matrix of thermodynamic factors from a single simulation in bulk. This approach relies on finite size effects of small systems on the density fluctuations. We present here an extension of their work for inhomogeneous Lennard Jones fluids confined in slit pores. We first verified this extension by cross validating the results obtained from this approach with the results obtained from the simulated adsorption isotherms, which allows to determine the thermodynamic factor in porous medium. We then studied the effects of the pore width (from 1 to 15 molecular sizes), of the solid-fluid interaction potential (Lennard Jones 9-3, hard wall potential) and of the reduced fluid density (from 0.1 to 0.7 at a reduced temperature T* = 2) on the thermodynamic factor. The deviation of the thermodynamic factor compared to its equivalent bulk value decreases when increasing the pore width and becomes insignificant for reduced pore width above 15. We also found that the thermodynamic factor is sensitive to the magnitude of the fluid-fluid and solid-fluid interactions, which softens or exacerbates the density fluctuations.

  9. INTRINSIC COLORS, TEMPERATURES, AND BOLOMETRIC CORRECTIONS OF PRE-MAIN-SEQUENCE STARS

    SciTech Connect

    Pecaut, Mark J.; Mamajek, Eric E.

    2013-09-01

    We present an analysis of the intrinsic colors and temperatures of 5-30 Myr old pre-main-sequence (pre-MS) stars using the F0- through M9-type members of nearby, negligibly reddened groups: the η Cha cluster, the TW Hydra Association, the β Pic Moving Group, and the Tucana-Horologium Association. To check the consistency of spectral types from the literature, we estimate new spectral types for 52 nearby pre-MS stars with spectral types F3 through M4 using optical spectra taken with the SMARTS 1.5 m telescope. Combining these new types with published spectral types and photometry from the literature (Johnson-Cousins BVI{sub C} , 2MASS JHK{sub S} and WISE W1, W2, W3, and W4), we derive a new empirical spectral type-color sequence for 5-30 Myr old pre-MS stars. Colors for pre-MS stars match dwarf colors for some spectral types and colors, but for other spectral types and colors, deviations can exceed 0.3 mag. We estimate effective temperatures (T {sub eff}) and bolometric corrections (BCs) for our pre-MS star sample through comparing their photometry to synthetic photometry generated using the BT-Settl grid of model atmosphere spectra. We derive a new T {sub eff} and BC scale for pre-MS stars, which should be a more appropriate match for T Tauri stars than often-adopted dwarf star scales. While our new T {sub eff} scale for pre-MS stars is within ≅100 K of dwarfs at a given spectral type for stars

  10. Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-main-sequence Stars

    NASA Astrophysics Data System (ADS)

    Pecaut, Mark J.; Mamajek, Eric E.

    2013-09-01

    We present an analysis of the intrinsic colors and temperatures of 5-30 Myr old pre-main-sequence (pre-MS) stars using the F0- through M9-type members of nearby, negligibly reddened groups: the η Cha cluster, the TW Hydra Association, the β Pic Moving Group, and the Tucana-Horologium Association. To check the consistency of spectral types from the literature, we estimate new spectral types for 52 nearby pre-MS stars with spectral types F3 through M4 using optical spectra taken with the SMARTS 1.5 m telescope. Combining these new types with published spectral types and photometry from the literature (Johnson-Cousins BVIC , 2MASS JHKS and WISE W1, W2, W3, and W4), we derive a new empirical spectral type-color sequence for 5-30 Myr old pre-MS stars. Colors for pre-MS stars match dwarf colors for some spectral types and colors, but for other spectral types and colors, deviations can exceed 0.3 mag. We estimate effective temperatures (T eff) and bolometric corrections (BCs) for our pre-MS star sample through comparing their photometry to synthetic photometry generated using the BT-Settl grid of model atmosphere spectra. We derive a new T eff and BC scale for pre-MS stars, which should be a more appropriate match for T Tauri stars than often-adopted dwarf star scales. While our new T eff scale for pre-MS stars is within sime100 K of dwarfs at a given spectral type for stars

  11. Monte Carlo calculated and experimentally determined output correction factors for small field detectors in Leksell Gamma Knife Perfexion beams.

    PubMed

    Benmakhlouf, H; Johansson, J; Paddick, I; Andreo, P

    2015-05-21

    The measurement of output factors (OF) for the small photon beams generated by Leksell Gamma Knife® (LGK) radiotherapy units is a challenge for the physicist due to the under or over estimation of these factors by a vast majority of the detectors commercially available. Output correction factors, introduced in the international formalism published by Alfonso (2008 Med. Phys. 35 5179-86), standardize the determination of OFs for small photon beams by correcting detector-reading ratios to yield OFs in terms of absorbed-dose ratios. In this work output correction factors for a number of detectors have been determined for LGK Perfexion™ (60)Co γ-ray beams by Monte Carlo (MC) calculations and measurements. The calculations were made with the MC system PENELOPE, scoring the energy deposited in the active volume of the detectors and in a small volume of water; the detectors simulated were two silicon diodes, one liquid ionization chamber (LIC), alanine and TLD. The calculated LIC output correction factors were within ± 0.4%, and this was selected as the reference detector for experimental determinations where output correction factors for twelve detectors were measured, normalizing their readings to those of the LIC. The MC-calculated and measured output correction factors for silicon diodes yielded corrections of up to 5% for the smallest LGK collimator size of 4 mm diameter. The air ionization chamber measurements led to extremely large output correction factors, caused by the well-known effect of partial volume averaging. The corrections were up to 7% for the natural diamond detector in the 4 mm collimator, also due to partial volume averaging, and decreased to within about ± 0.6% for the smaller synthetic diamond detector. The LIC, showing the smallest corrections, was used to investigate machine-to-machine output factor differences by performing measurements in four LGK units with different dose rates. These resulted in OFs within ± 0.6% and

  12. Evaluation of inhomogeneity correction factors for 6 MV flattening filter-free beams with brass compensators.

    PubMed

    Robinson, Joshua; Opp, Daniel; Zhang, Geoffrey; Feygelman, Vladimir

    2013-01-01

    The 6 MV flattening filter-free (FFF) beam has been commissioned for use with compensators at our institution. This novel combination promises advantages in mitigating tumor motion due to the reduced treatment time made possible by the greatly increased dose rate of the FFF beam. Given the different energy spectrum of the FFF beam and the beam hardening effect of the compensator, the accuracy of the treatment planning system (TPS) model in the presence of low-density heterogeneities cannot be assumed. Therefore, inhomogeneity correction factors (ICF) for an FFF beam attenuated by brass slabs were measured and compared to the TPS calculations in this work. The ICF is the ratio of the point dose in the presence of inhomogeneity to the dose in the same point in a homogeneous medium. The ICFs were measured with an ion chamber at a number of points in a flat water-equivalent slab phantom containing a 7.5 cm deep heterogeneity (air or 0.27 g/cm3 wood). Comparisons for the FFF beam were carried out for the field sizes from 5× 5 to 20 × 20 cm2 with the brass slabs ranging from 0 to 5 cm in thickness. For a low-density wood heterogeneity in a slab phantom, with the exception of the point 1cm beyond the proximal buildup interface, the TPS handles the inhomogeneity correction with the brass-filtered 6 MV FFF beam at the requisite 2% error level. The combinations of field sizes and compensator thicknesses when the error exceeds 2% (2.6% maximum) are not likely to be experienced in clinical practice. In terms of heterogeneity corrections, the beam model is adequate for clinical use.

  13. Geometric correction factor for transepithelial electrical resistance measurements in transwell and microfluidic cell cultures

    NASA Astrophysics Data System (ADS)

    Yeste, J.; Illa, X.; Gutiérrez, C.; Solé, M.; Guimerà, A.; Villa, R.

    2016-09-01

    Transepithelial electrical resistance (TEER) measurements are regularly used in in vitro models to quantitatively evaluate the cell barrier function. Although it would be expected that TEER values obtained with the same cell type and experimental setup were comparable, values reported in the literature show a large dispersion for unclear reasons. This work highlights a possible error in a widely used formula to calculate the TEER, in which it may be erroneously assumed that the entire cell culture area contributes equally to the measurement. In this study, we have numerically calculated this error in some cell cultures previously reported. In particular, we evidence that some TEER measurements resulted in errors when measuring low TEERs, especially when using Transwell inserts 12 mm in diameter or microfluidic systems that have small chamber heights. To correct this error, we propose the use of a geometric correction factor (GCF) for calculating the TEER. In addition, we describe a simple method to determine the GCF of a particular measurement system, so that it can be applied retrospectively. We have also experimentally validated an interdigitated electrodes (IDE) configuration where the entire cell culture area contributes equally to the measurement, and it also implements minimal electrode coverage so that the cells can be visualized alongside TEER analysis.

  14. Correction analysis for a supersonic water cooled total temperature probe tested to 1370 K

    NASA Technical Reports Server (NTRS)

    Lagen, Nicholas T.; Seiner, John M.

    1991-01-01

    The authors address the thermal analysis of a water cooled supersonic total temperature probe tested in a Mach 2 flow, up to 1366 K total temperature. The goal of this experiment was the determination of high-temperature supersonic jet mean flow temperatures. An 8.99 cm exit diameter water cooled nozzle was used in the tests. It was designed for exit Mach 2 at 1366 K exit total temperature. Data along the jet centerline were obtained for total temperatures of 755 K, 1089 K, and 1366 K. The data from the total temperature probe were affected by the water coolant. The probe was tested through a range of temperatures between 755 K and 1366 K with and without the cooling system turned on. The results were used to develop a relationship between the indicated thermocouple bead temperature and the freestream total temperature. The analysis and calculated temperatures are presented.

  15. SU-C-304-07: Are Small Field Detector Correction Factors Strongly Dependent On Machine-Specific Characteristics?

    SciTech Connect

    Mathew, D; Tanny, S; Parsai, E; Sperling, N

    2015-06-15

    Purpose: The current small field dosimetry formalism utilizes quality correction factors to compensate for the difference in detector response relative to dose deposited in water. The correction factors are defined on a machine-specific basis for each beam quality and detector combination. Some research has suggested that the correction factors may only be weakly dependent on machine-to-machine variations, allowing for determinations of class-specific correction factors for various accelerator models. This research examines the differences in small field correction factors for three detectors across two Varian Truebeam accelerators to determine the correction factor dependence on machine-specific characteristics. Methods: Output factors were measured on two Varian Truebeam accelerators for equivalently tuned 6 MV and 6 FFF beams. Measurements were obtained using a commercial plastic scintillation detector (PSD), two ion chambers, and a diode detector. Measurements were made at a depth of 10 cm with an SSD of 100 cm for jaw-defined field sizes ranging from 3×3 cm{sup 2} to 0.6×0.6 cm{sup 2}, normalized to values at 5×5cm{sup 2}. Correction factors for each field on each machine were calculated as the ratio of the detector response to the PSD response. Percent change of correction factors for the chambers are presented relative to the primary machine. Results: The Exradin A26 demonstrates a difference of 9% for 6×6mm{sup 2} fields in both the 6FFF and 6MV beams. The A16 chamber demonstrates a 5%, and 3% difference in 6FFF and 6MV fields at the same field size respectively. The Edge diode exhibits less than 1.5% difference across both evaluated energies. Field sizes larger than 1.4×1.4cm2 demonstrated less than 1% difference for all detectors. Conclusion: Preliminary results suggest that class-specific correction may not be appropriate for micro-ionization chamber. For diode systems, the correction factor was substantially similar and may be useful for class

  16. Polarity correction factor for flattening filter free photon beams in several cylindrical ionization chambers.

    PubMed

    Ogata, Toshiyuki; Uehara, Kazuyuki; Nakayama, Masao; Tsudou, Shinji; Masutani, Takashi; Okayama, Takanobu

    2016-07-01

    In this study, we aimed to compare the polarity correction factor in ionization chambers for flattening filter free (FFF) photon beams and flattening filter (FF) beams. Measurements were performed with both 6 and 10 MV FFF and FF beams. Five commercial ionization chambers were evaluated: PTW TN30013; IBA Dosimetry CC01, CC04, and CC13; and Exradin A12S. Except for the CC01 ionization chamber, the other four chambers showed less than a 0.3 % difference in the polarity effect between the FFF and the FF beams. The CC01 chamber showed a strong field-size-dependence, unlike the other chambers. The polarity effect for all chambers with FFF beams did not change with the dose rate. Except in the case of the CC01 chamber, the difference in the polarity effect between FFF and FF beams was not significant.

  17. Design and real time implementation of single phase boost power factor correction converter.

    PubMed

    Bouafassa, Amar; Rahmani, Lazhar; Mekhilef, Saad

    2015-03-01

    This paper presents a real time implementation of the single-phase power factor correction (PFC) AC-DC boost converter. A combination of higher order sliding mode controller based on super twisting algorithm and predictive control techniques are implemented to improve the performance of the boost converter. Due to the chattering effects, the higher order sliding mode control (HOSMC) is designed. Also, the predictive technique is modified taking into account the large computational delays. The robustness of the controller is verified conducting simulation in MATLAB, the results show good performances in both steady and transient states. An experiment is conducted through a test bench based on dSPACE 1104. The experimental results proved that the proposed controller enhanced the performance of the converter under different parameters variations.

  18. Design and real time implementation of single phase boost power factor correction converter.

    PubMed

    Bouafassa, Amar; Rahmani, Lazhar; Mekhilef, Saad

    2015-03-01

    This paper presents a real time implementation of the single-phase power factor correction (PFC) AC-DC boost converter. A combination of higher order sliding mode controller based on super twisting algorithm and predictive control techniques are implemented to improve the performance of the boost converter. Due to the chattering effects, the higher order sliding mode control (HOSMC) is designed. Also, the predictive technique is modified taking into account the large computational delays. The robustness of the controller is verified conducting simulation in MATLAB, the results show good performances in both steady and transient states. An experiment is conducted through a test bench based on dSPACE 1104. The experimental results proved that the proposed controller enhanced the performance of the converter under different parameters variations. PMID:25457043

  19. Monte Carlo calculations of correction factors for plane-parallel ionization chambers in clinical electron dosimetry

    SciTech Connect

    Araki, Fujio

    2008-09-15

    Recent standard dosimetry protocols recommend that plane-parallel ionization chambers be used in the measurements of depth-dose distributions or the calibration of low-energy electron beams with beam quality R{sub 50}<4 g/cm{sup 2}. In electron dosimetry protocols with the plane-parallel chambers, the wall correction factor, P{sub wall}, in water is assumed to be unity and the replacement correction factor, P{sub repl}, is taken to be unity for well-guarded plane-parallel chambers, at all measurement depths. This study calculated P{sub wall} and P{sub repl} for NACP-02, Markus, and Roos plane-parallel chambers in clinical electron dosimetry using the EGSnrc Monte Carlo code system. The P{sub wall} values for the plane-parallel chambers increased rapidly as a function of depth in water, especially at lower energy. The value around R{sub 50} for NACP-02 was about 10% greater than unity at 4 MeV. The effect was smaller for higher electron energies. Similarly, P{sub repl} values with depth increased drastically at the region with the steep dose gradient for lower energy. For Markus P{sub repl} departed more than 10% from unity close to R{sub 50} due to the narrow guard ring width. P{sub repl} for NACP-02 and Roos was close to unity in the plateau region of depth-dose curves that includes a reference depth, d{sub ref}. It was also found that the ratio of the dose to water and the dose to the sensitive volume in the air cavity for the plane-parallel chambers, D{sub w}/[D{sub air}]{sub pp}, at d{sub ref} differs significantly from that assumed by electron dosimetry protocols.

  20. Calibration of Gyros with Temperature Dependent Scale Factors

    NASA Technical Reports Server (NTRS)

    Belur, Sheela V.; Harman, Richard

    2001-01-01

    The general problem of gyro calibration can be stated as the estimation of the scale factors, misalignments, and drift-rate biases of the gyro using the on-orbit sensor measurements. These gyro parameters have been traditionally treated as temperature-independent in the operational flight dynamics ground systems at NASA Goddard Space Flight Center (GSFC), a scenario which has been successfully applied in the gyro calibration of a large number of missions. A significant departure from this is the Microwave Anisotropy Probe (MAP) mission where, due to the high thermal variations expected during the mission phase, it is necessary to model the scale factors as functions of temperature. This paper addresses the issue of gyro calibration for the MAP gyro model using a manufacturer-supplied model of the variation of scale factors with temperature. The problem is formulated as a least squares problem and solved using the Levenberg-Marquardt algorithm in the MATLAB(R) library function NLSQ. The algorithm was tested on simulated data with Gaussian noise for the quaternions as well as the gyro rates and was found to consistently converge close to the true values. Significant improvement in accuracy was noticed due to the estimation of the temperature-dependent scale factors as against constant scale factors.

  1. Error Detection, Factorization and Correction for Multi-View Scene Reconstruction from Aerial Imagery

    SciTech Connect

    Hess-Flores, Mauricio

    2011-11-10

    Scene reconstruction from video sequences has become a prominent computer vision research area in recent years, due to its large number of applications in fields such as security, robotics and virtual reality. Despite recent progress in this field, there are still a number of issues that manifest as incomplete, incorrect or computationally-expensive reconstructions. The engine behind achieving reconstruction is the matching of features between images, where common conditions such as occlusions, lighting changes and texture-less regions can all affect matching accuracy. Subsequent processes that rely on matching accuracy, such as camera parameter estimation, structure computation and non-linear parameter optimization, are also vulnerable to additional sources of error, such as degeneracies and mathematical instability. Detection and correction of errors, along with robustness in parameter solvers, are a must in order to achieve a very accurate final scene reconstruction. However, error detection is in general difficult due to the lack of ground-truth information about the given scene, such as the absolute position of scene points or GPS/IMU coordinates for the camera(s) viewing the scene. In this dissertation, methods are presented for the detection, factorization and correction of error sources present in all stages of a scene reconstruction pipeline from video, in the absence of ground-truth knowledge. Two main applications are discussed. The first set of algorithms derive total structural error measurements after an initial scene structure computation and factorize errors into those related to the underlying feature matching process and those related to camera parameter estimation. A brute-force local correction of inaccurate feature matches is presented, as well as an improved conditioning scheme for non-linear parameter optimization which applies weights on input parameters in proportion to estimated camera parameter errors. Another application is in

  2. How should forensic anthropologists correct national weather service temperature data for use in estimating the postmortem interval?

    PubMed

    Dabbs, Gretchen R

    2015-05-01

    This study examines the correlation between site-specific and retrospectively collected temperature data from the National Weather Service (NWS) over an extended time period. Using iButtonLink thermochrons (model DS1921G), hourly temperature readings were collected at 15 sites (1 validation; 14 experimental) from December 2010 to January 2012. Comparison between the site-specific temperature data and data retrieved from an official reporter of NWS temperature data shows statistically significant differences between the two in 71.4% (10/14) of cases. The difference ranged between 0.04 and 2.81°C. Examination of both regression and simple adjustment of the mean difference over extended periods (1, 2, 3, 4, 5, 6, & 9 months) suggests that on the timescale typical in forensic anthropology cases neither method of correction is consistent or reliable and that forensic anthropologists would be better suited using uncorrected NWS temperature data when the postmortem interval is extended.

  3. LETTER TO THE EDITOR: On the pdis correction factor for cylindrical chambers

    NASA Astrophysics Data System (ADS)

    Andreo, Pedro

    2010-03-01

    The authors of a recent paper (Wang and Rogers 2009 Phys. Med. Biol. 54 1609) have used the Monte Carlo method to simulate the 'classical' experiment made more than 30 years ago by Johansson et al (1978 National and International Standardization of Radiation Dosimetry (Atlanta 1977) vol 2 (Vienna: IAEA) pp 243-70) on the displacement (or replacement) perturbation correction factor pdis for cylindrical chambers in 60Co and high-energy photon beams. They conclude that an 'unreasonable normalization at dmax' of the ionization chambers response led to incorrect results, and for the IAEA TRS-398 Code of Practice, which uses ratios of those results, 'the difference in the correction factors can lead to a beam calibration deviation of more than 0.5% for Farmer-like chambers'. The present work critically examines and questions some of the claims and generalized conclusions of the paper. It is demonstrated that for real, commercial Farmer-like chambers, the possible deviations in absorbed dose would be much smaller (typically 0.13%) than those stated by Wang and Rogers, making the impact of their proposed values negligible on practical high-energy photon dosimetry. Differences of the order of 0.4% would only appear at the upper extreme of the energies potentially available for clinical use (around 25 MV) and, because lower energies are more frequently used, the number of radiotherapy photon beams for which the deviations would be larger than say 0.2% is extremely small. This work also raises concerns on the proposed value of pdis for Farmer chambers at the reference quality of 60Co in relation to their impact on electron beam dosimetry, both for direct dose determination using these chambers and for the cross-calibration of plane-parallel chambers. The proposed increase of about 1% in pdis (compared with TRS-398) would lower the kQ factors and therefore Dw in electron beams by the same amount. This would yield a severe discrepancy with the current good agreement between

  4. A Power Factor Corrected SMPS with Improved Power Quality for Welding Applications

    NASA Astrophysics Data System (ADS)

    Narula, Swati; Singh, Bhim; Bhuvaneswari, G.; Pandey, Rahul

    2015-04-01

    This paper presents the analysis, design and implementation of a power factor corrected Arc Welding Power Supply (AWPS) with a boost converter at the front end and three full-bridge (FB) converters connected in parallel at the load end. The modular arrangement of the FB converters offers several meritorious features like usage of power devices with comparatively lower voltage and current ratings, ease of power expandability, easy maintenance, etc. The boost converter operates in continuous conduction mode minimizing the input current ripple and leading to the lowest RMS current thereby improving the input power quality. Individual control loops are designed for each power stage. A dual loop control scheme is employed to incorporate over-current limit on the proposed AWPS which ensures excellent weld bead quality. The proposed AWPS is implemented to validate its performance over a wide range of line/load variations. Test results confirm its fast parametrical response to load and source voltage variations and over-current protection leading to improved welding performance and weld bead quality. The system is found to perform extremely well with very low input current THD and unity power factor, adhering to international power quality norms.

  5. A Physically Based Algorithm for Non-Blackbody Correction of Cloud-Top Temperature and Application to Convection Study

    NASA Technical Reports Server (NTRS)

    Wang, Chunpeng; Lou, Zhengzhao Johnny; Chen, Xiuhong; Zeng, Xiping; Tao, Wei-Kuo; Huang, Xianglei

    2014-01-01

    Cloud-top temperature (CTT) is an important parameter for convective clouds and is usually different from the 11-micrometers brightness temperature due to non-blackbody effects. This paper presents an algorithm for estimating convective CTT by using simultaneous passive [Moderate Resolution Imaging Spectroradiometer (MODIS)] and active [CloudSat 1 Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)] measurements of clouds to correct for the non-blackbody effect. To do this, a weighting function of the MODIS 11-micrometers band is explicitly calculated by feeding cloud hydrometer profiles from CloudSat and CALIPSO retrievals and temperature and humidity profiles based on ECMWF analyses into a radiation transfer model.Among 16 837 tropical deep convective clouds observed by CloudSat in 2008, the averaged effective emission level (EEL) of the 11-mm channel is located at optical depth; approximately 0.72, with a standard deviation of 0.3. The distance between the EEL and cloud-top height determined by CloudSat is shown to be related to a parameter called cloud-top fuzziness (CTF), defined as the vertical separation between 230 and 10 dBZ of CloudSat radar reflectivity. On the basis of these findings a relationship is then developed between the CTF and the difference between MODIS 11-micrometers brightness temperature and physical CTT, the latter being the non-blackbody correction of CTT. Correction of the non-blackbody effect of CTT is applied to analyze convective cloud-top buoyancy. With this correction, about 70% of the convective cores observed by CloudSat in the height range of 6-10 km have positive buoyancy near cloud top, meaning clouds are still growing vertically, although their final fate cannot be determined by snapshot observations.

  6. Intraosseous delivery of lentiviral vectors targeting factor VIII expression in platelets corrects murine hemophilia A.

    PubMed

    Wang, Xuefeng; Shin, Simon C; Chiang, Andy F J; Khan, Iram; Pan, Dao; Rawlings, David J; Miao, Carol H

    2015-04-01

    Intraosseous (IO) infusion of lentiviral vectors (LVs) for in situ gene transfer into bone marrow may avoid specific challenges posed by ex vivo gene delivery, including, in particular, the requirement of preconditioning. We utilized IO delivery of LVs encoding a GFP or factor VIII (FVIII) transgene directed by ubiquitous promoters (a MND or EF-1α-short element; M-GFP-LV, E-F8-LV) or a platelet-specific, glycoprotein-1bα promoter (G-GFP-LV, G-F8-LV). A single IO infusion of M-GFP-LV or G-GFP-LV achieved long-term and efficient GFP expression in Lineage(-)Sca1(+)c-Kit(+) hematopoietic stem cells and platelets, respectively. While E-F8-LV produced initially high-level FVIII expression, robust anti-FVIII immune responses eliminated functional FVIII in circulation. In contrast, IO delivery of G-F8-LV achieved long-term platelet-specific expression of FVIII, resulting in partial correction of hemophilia A. Furthermore, similar clinical benefit with G-F8-LV was achieved in animals with pre-existing anti-FVIII inhibitors. These findings further support platelets as an ideal FVIII delivery vehicle, as FVIII, stored in α-granules, is protected from neutralizing antibodies and, during bleeding, activated platelets locally excrete FVIII to promote clot formation. Overall, a single IO infusion of G-F8-LV was sufficient to correct hemophilia phenotype for long term, indicating that this approach may provide an effective means to permanently treat FVIII deficiency. PMID:25655313

  7. Intraosseous Delivery of Lentiviral Vectors Targeting Factor VIII Expression in Platelets Corrects Murine Hemophilia A

    PubMed Central

    Wang, Xuefeng; Shin, Simon C; Chiang, Andy F J; Khan, Iram; Pan, Dao; Rawlings, David J; Miao, Carol H

    2015-01-01

    Intraosseous (IO) infusion of lentiviral vectors (LVs) for in situ gene transfer into bone marrow may avoid specific challenges posed by ex vivo gene delivery, including, in particular, the requirement of preconditioning. We utilized IO delivery of LVs encoding a GFP or factor VIII (FVIII) transgene directed by ubiquitous promoters (a MND or EF-1α-short element; M-GFP-LV, E-F8-LV) or a platelet-specific, glycoprotein-1bα promoter (G-GFP-LV, G-F8-LV). A single IO infusion of M-GFP-LV or G-GFP-LV achieved long-term and efficient GFP expression in Lineage-Sca1+c-Kit+ hematopoietic stem cells and platelets, respectively. While E-F8-LV produced initially high-level FVIII expression, robust anti-FVIII immune responses eliminated functional FVIII in circulation. In contrast, IO delivery of G-F8-LV achieved long-term platelet-specific expression of FVIII, resulting in partial correction of hemophilia A. Furthermore, similar clinical benefit with G-F8-LV was achieved in animals with pre-existing anti-FVIII inhibitors. These findings further support platelets as an ideal FVIII delivery vehicle, as FVIII, stored in α-granules, is protected from neutralizing antibodies and, during bleeding, activated platelets locally excrete FVIII to promote clot formation. Overall, a single IO infusion of G-F8-LV was sufficient to correct hemophilia phenotype for long term, indicating that this approach may provide an effective means to permanently treat FVIII deficiency. PMID:25655313

  8. Detector to detector corrections: A comprehensive experimental study of detector specific correction factors for beam output measurements for small radiotherapy beams

    SciTech Connect

    Azangwe, Godfrey Grochowska, Paulina; Izewska, Joanna; Meghzifene, Ahmed; Georg, Dietmar; Hopfgartner, Johannes; Lechner, Wolfgang; Mizuno, Hideyuki; Fukumura, Akifumi; Yajima, Kaori; Gouldstone, Clare; Sharpe, Peter; Palmans, Hugo

    2014-07-15

    Purpose: The aim of the present study is to provide a comprehensive set of detector specific correction factors for beam output measurements for small beams, for a wide range of real time and passive detectors. The detector specific correction factors determined in this study may be potentially useful as a reference data set for small beam dosimetry measurements. Methods: Dose response of passive and real time detectors was investigated for small field sizes shaped with a micromultileaf collimator ranging from 0.6 × 0.6 cm{sup 2} to 4.2 × 4.2 cm{sup 2} and the measurements were extended to larger fields of up to 10 × 10 cm{sup 2}. Measurements were performed at 5 cm depth, in a 6 MV photon beam. Detectors used included alanine, thermoluminescent dosimeters (TLDs), stereotactic diode, electron diode, photon diode, radiophotoluminescent dosimeters (RPLDs), radioluminescence detector based on carbon-doped aluminium oxide (Al{sub 2}O{sub 3}:C), organic plastic scintillators, diamond detectors, liquid filled ion chamber, and a range of small volume air filled ionization chambers (volumes ranging from 0.002 cm{sup 3} to 0.3 cm{sup 3}). All detector measurements were corrected for volume averaging effect and compared with dose ratios determined from alanine to derive a detector correction factors that account for beam perturbation related to nonwater equivalence of the detector materials. Results: For the detectors used in this study, volume averaging corrections ranged from unity for the smallest detectors such as the diodes, 1.148 for the 0.14 cm{sup 3} air filled ionization chamber and were as high as 1.924 for the 0.3 cm{sup 3} ionization chamber. After applying volume averaging corrections, the detector readings were consistent among themselves and with alanine measurements for several small detectors but they differed for larger detectors, in particular for some small ionization chambers with volumes larger than 0.1 cm{sup 3}. Conclusions: The results demonstrate

  9. Implicit temperature-correction-based immersed-boundary thermal lattice Boltzmann method for the simulation of natural convection

    NASA Astrophysics Data System (ADS)

    Seta, Takeshi

    2013-06-01

    In the present paper, we apply the implicit-correction method to the immersed-boundary thermal lattice Boltzmann method (IB-TLBM) for the natural convection between two concentric horizontal cylinders and in a square enclosure containing a circular cylinder. The Chapman-Enskog multiscale expansion proves the existence of an extra term in the temperature equation from the source term of the kinetic equation. In order to eliminate the extra term, we redefine the temperature and the source term in the lattice Boltzmann equation. When the relaxation time is less than unity, the new definition of the temperature and source term enhances the accuracy of the thermal lattice Boltzmann method. The implicit-correction method is required in order to calculate the thermal interaction between a fluid and a rigid solid using the redefined temperature. Simulation of the heat conduction between two concentric cylinders indicates that the error at each boundary point of the proposed IB-TLBM is reduced by the increment of the number of Lagrangian points constituting the boundaries. We derive the theoretical relation between a temperature slip at the boundary and the relaxation time and demonstrate that the IB-TLBM requires a small relaxation time in order to avoid temperature distortion around the immersed boundary. The streamline, isotherms, and average Nusselt number calculated by the proposed method agree well with those of previous numerical studies involving natural convection. The proposed IB-TLBM improves the accuracy of the boundary conditions for the temperature and velocity using an adequate discrete area for each of the Lagrangian nodes and reduces the penetration of the streamline on the surface of the body.

  10. Implicit temperature-correction-based immersed-boundary thermal lattice Boltzmann method for the simulation of natural convection.

    PubMed

    Seta, Takeshi

    2013-06-01

    In the present paper, we apply the implicit-correction method to the immersed-boundary thermal lattice Boltzmann method (IB-TLBM) for the natural convection between two concentric horizontal cylinders and in a square enclosure containing a circular cylinder. The Chapman-Enskog multiscale expansion proves the existence of an extra term in the temperature equation from the source term of the kinetic equation. In order to eliminate the extra term, we redefine the temperature and the source term in the lattice Boltzmann equation. When the relaxation time is less than unity, the new definition of the temperature and source term enhances the accuracy of the thermal lattice Boltzmann method. The implicit-correction method is required in order to calculate the thermal interaction between a fluid and a rigid solid using the redefined temperature. Simulation of the heat conduction between two concentric cylinders indicates that the error at each boundary point of the proposed IB-TLBM is reduced by the increment of the number of Lagrangian points constituting the boundaries. We derive the theoretical relation between a temperature slip at the boundary and the relaxation time and demonstrate that the IB-TLBM requires a small relaxation time in order to avoid temperature distortion around the immersed boundary. The streamline, isotherms, and average Nusselt number calculated by the proposed method agree well with those of previous numerical studies involving natural convection. The proposed IB-TLBM improves the accuracy of the boundary conditions for the temperature and velocity using an adequate discrete area for each of the Lagrangian nodes and reduces the penetration of the streamline on the surface of the body.

  11. Correction factors for determination of annual average radon concentration in dwellings of Poland resulting from seasonal variability of indoor radon.

    PubMed

    Kozak, K; Mazur, J; Kozłowska, B; Karpińska, M; Przylibski, T A; Mamont-Cieśla, K; Grządziel, D; Stawarz, O; Wysocka, M; Dorda, J; Zebrowski, A; Olszewski, J; Hovhannisyan, H; Dohojda, M; Kapała, J; Chmielewska, I; Kłos, B; Jankowski, J; Mnich, S; Kołodziej, R

    2011-10-01

    The method for the calculation of correction factors is presented, which can be used for the assessment of the mean annual radon concentration on the basis of 1-month or 3-month indoor measurements. Annual radon concentration is an essential value for the determination of the annual dose due to radon inhalation. The measurements have been carried out in 132 houses in Poland over a period of one year. The passive method of track detectors with CR-39 foil was applied. Four thermal-precipitation regions in Poland were established and correction factors were calculated for each region, separately for houses with and without basements.

  12. Fluence correction factors for graphite calorimetry in a low-energy clinical proton beam: I. Analytical and Monte Carlo simulations.

    PubMed

    Palmans, H; Al-Sulaiti, L; Andreo, P; Shipley, D; Lühr, A; Bassler, N; Martinkovič, J; Dobrovodský, J; Rossomme, S; Thomas, R A S; Kacperek, A

    2013-05-21

    The conversion of absorbed dose-to-graphite in a graphite phantom to absorbed dose-to-water in a water phantom is performed by water to graphite stopping power ratios. If, however, the charged particle fluence is not equal at equivalent depths in graphite and water, a fluence correction factor, kfl, is required as well. This is particularly relevant to the derivation of absorbed dose-to-water, the quantity of interest in radiotherapy, from a measurement of absorbed dose-to-graphite obtained with a graphite calorimeter. In this work, fluence correction factors for the conversion from dose-to-graphite in a graphite phantom to dose-to-water in a water phantom for 60 MeV mono-energetic protons were calculated using an analytical model and five different Monte Carlo codes (Geant4, FLUKA, MCNPX, SHIELD-HIT and McPTRAN.MEDIA). In general the fluence correction factors are found to be close to unity and the analytical and Monte Carlo codes give consistent values when considering the differences in secondary particle transport. When considering only protons the fluence correction factors are unity at the surface and increase with depth by 0.5% to 1.5% depending on the code. When the fluence of all charged particles is considered, the fluence correction factor is about 0.5% lower than unity at shallow depths predominantly due to the contributions from alpha particles and increases to values above unity near the Bragg peak. Fluence correction factors directly derived from the fluence distributions differential in energy at equivalent depths in water and graphite can be described by kfl = 0.9964 + 0.0024·zw-eq with a relative standard uncertainty of 0.2%. Fluence correction factors derived from a ratio of calculated doses at equivalent depths in water and graphite can be described by kfl = 0.9947 + 0.0024·zw-eq with a relative standard uncertainty of 0.3%. These results are of direct relevance to graphite calorimetry in low-energy protons but given that the fluence

  13. Continuous correction of differential path length factor in near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Talukdar, Tanveer; Moore, Jason H.; Diamond, Solomon G.

    2013-05-01

    In continuous-wave near-infrared spectroscopy (CW-NIRS), changes in the concentration of oxyhemoglobin and deoxyhemoglobin can be calculated by solving a set of linear equations from the modified Beer-Lambert Law. Cross-talk error in the calculated hemodynamics can arise from inaccurate knowledge of the wavelength-dependent differential path length factor (DPF). We apply the extended Kalman filter (EKF) with a dynamical systems model to calculate relative concentration changes in oxy- and deoxyhemoglobin while simultaneously estimating relative changes in DPF. Results from simulated and experimental CW-NIRS data are compared with results from a weighted least squares (WLSQ) method. The EKF method was found to effectively correct for artificially introduced errors in DPF and to reduce the cross-talk error in simulation. With experimental CW-NIRS data, the hemodynamic estimates from EKF differ significantly from the WLSQ (p<0.001). The cross-correlations among residuals at different wavelengths were found to be significantly reduced by the EKF method compared to WLSQ in three physiologically relevant spectral bands 0.04 to 0.15 Hz, 0.15 to 0.4 Hz and 0.4 to 2.0 Hz (p<0.001). This observed reduction in residual cross-correlation is consistent with reduced cross-talk error in the hemodynamic estimates from the proposed EKF method.

  14. Continuous correction of differential path length factor in near-infrared spectroscopy

    PubMed Central

    Moore, Jason H.; Diamond, Solomon G.

    2013-01-01

    Abstract. In continuous-wave near-infrared spectroscopy (CW-NIRS), changes in the concentration of oxyhemoglobin and deoxyhemoglobin can be calculated by solving a set of linear equations from the modified Beer-Lambert Law. Cross-talk error in the calculated hemodynamics can arise from inaccurate knowledge of the wavelength-dependent differential path length factor (DPF). We apply the extended Kalman filter (EKF) with a dynamical systems model to calculate relative concentration changes in oxy- and deoxyhemoglobin while simultaneously estimating relative changes in DPF. Results from simulated and experimental CW-NIRS data are compared with results from a weighted least squares (WLSQ) method. The EKF method was found to effectively correct for artificially introduced errors in DPF and to reduce the cross-talk error in simulation. With experimental CW-NIRS data, the hemodynamic estimates from EKF differ significantly from the WLSQ (p<0.001). The cross-correlations among residuals at different wavelengths were found to be significantly reduced by the EKF method compared to WLSQ in three physiologically relevant spectral bands 0.04 to 0.15 Hz, 0.15 to 0.4 Hz and 0.4 to 2.0 Hz (p<0.001). This observed reduction in residual cross-correlation is consistent with reduced cross-talk error in the hemodynamic estimates from the proposed EKF method. PMID:23640027

  15. Continuous correction of differential path length factor in near-infrared spectroscopy.

    PubMed

    Talukdar, Tanveer; Moore, Jason H; Diamond, Solomon G

    2013-05-01

    In continuous-wave near-infrared spectroscopy (CW-NIRS), changes in the concentration of oxyhemoglobin and deoxyhemoglobin can be calculated by solving a set of linear equations from the modified Beer-Lambert Law. Cross-talk error in the calculated hemodynamics can arise from inaccurate knowledge of the wavelength-dependent differential path length factor (DPF). We apply the extended Kalman filter (EKF) with a dynamical systems model to calculate relative concentration changes in oxy- and deoxyhemoglobin while simultaneously estimating relative changes in DPF. Results from simulated and experimental CW-NIRS data are compared with results from a weighted least squares (WLSQ) method. The EKF method was found to effectively correct for artificially introduced errors in DPF and to reduce the cross-talk error in simulation. With experimental CW-NIRS data, the hemodynamic estimates from EKF differ significantly from the WLSQ (p < 0.001). The cross-correlations among residuals at different wavelengths were found to be significantly reduced by the EKF method compared to WLSQ in three physiologically relevant spectral bands 0.04 to 0.15 Hz, 0.15 to 0.4 Hz and 0.4 to 2.0 Hz (p < 0.001). This observed reduction in residual cross-correlation is consistent with reduced cross-talk error in the hemodynamic estimates from the proposed EKF method. PMID:23640027

  16. Sulphur abundance determinations in star-forming regions - I. Ionization correction factor

    NASA Astrophysics Data System (ADS)

    Dors, O. L.; Pérez-Montero, E.; Hägele, G. F.; Cardaci, M. V.; Krabbe, A. C.

    2016-03-01

    In this work, we used a grid of photoionization models combined with stellar population synthesis models to derive reliable ionization correction factors (ICFs) for the sulphur in star-forming regions. These models cover a large range of nebular parameters and yielding ionic abundances in consonance with those derived through optical and infrared observational data of star-forming regions. From our theoretical ICFs, we suggested an α value of 3.27 ± 0.01 in the classical Stasińska formulae. We compared the total sulphur abundance in the gas phase of a large sample of objects by using our theoretical ICF and other approaches. In average, the differences between the determinations via the use of the different ICFs considered are similar to the uncertainties in the S/H estimations. Nevertheless, we noted that for some objects it could reach up to about 0.3 dex for the low-metallicity regime. Despite of the large scatter of the points, we found a trend of S/O ratio to decrease with the metallicity, independently of the ICF used to compute the sulphur total abundance.

  17. Control of Dual-Opposed Stirling Convertors with Active Power Factor Correction Controllers

    NASA Technical Reports Server (NTRS)

    Regan, Timothy F.; Lewandowski, Edward J.; Schreiber, Jeffrey G.

    2006-01-01

    When using recently-developed active power factor correction (APFC) controllers in power systems comprised of dual-opposed free-piston Stirling convertors, a variety of configurations of the convertors and controller(s) can be considered, with configuration ultimately selected based on benefits of efficiency, reliability, and robust operation. The configuration must not only achieve stable control of the two convertors, but also synchronize and regulate motion of the pistons to minimize net dynamic forces. The NASA Glenn Research Center (GRC) System Dynamic Model (SDM) was used to study ten configurations of dual-opposed convertor systems. These configurations considered one controller with the alternators connected in series or in parallel, and two controllers with the alternators not connected (isolated). For the configurations where the alternators were not connected, several different approaches were evaluated to synchronize the two convertors. In addition, two thermodynamic configurations were considered: two convertors with isolated working spaces and convertors with a shared expansion space. Of the ten configurations studied, stable operating modes were found for four. Three of those four had a common expansion space. One stable configuration was found for the dual-opposed convertors with separate working spaces. That configuration required isochronous control of both convertors, and two APFC controllers were used to accomplish this. A frequency/phase control loop was necessary to allow each APFC controller to synchronize its associated convertor with a common frequency.

  18. Control of Dual-Opposed Stirling Convertors with Active Power Factor Correction Controllers

    NASA Technical Reports Server (NTRS)

    Regan, Timothy F.; Lewandowski, Edward J.; Schreiber, Jeffrey G.

    2007-01-01

    When using recently-developed active power factor correction (APFC) controllers in power systems comprised of dual-opposed free-piston Stirling convertors, a variety of configurations of the convertors and controller(s) can be considered, with configuration ultimately selected based on benefits of efficiency, reliability, and robust operation. The configuration must not only achieve stable control of the two convertors, but also synchronize and regulate motion of the pistons to minimize net dynamic forces. The NASA Glenn Research Center (GRC) System Dynamic Model (SDM) was used to study ten configurations of dual-opposed convertor systems. These configurations considered one controller with the alternators connected in series or in parallel, and two controllers with the alternators not connected (isolated). For the configurations where the alternators were not connected, several different approaches were evaluated to synchronize the two convertors. In addition, two thermodynamic configurations were considered: two convertors with isolated working spaces and convertors with a shared expansion space. Of the ten configurations studied, stable operating modes were found for four. Three of those four had a common expansion space. One stable configuration was found for the dual-opposed convertors with separate working spaces. That configuration required isochronous control of both convertors, and two APFC controllers were used to accomplish this. A frequency/phase control loop was necessary to allow each APFC controller to synchronize its associated convertor with a common frequency.

  19. Myopia Stabilization and Associated Factors Among Participants in the Correction of Myopia Evaluation Trial (COMET)

    PubMed Central

    2013-01-01

    Purpose. To use the Gompertz function to estimate the age and the amount of myopia at stabilization and to evaluate associated factors in the Correction of Myopia Evaluation Trial (COMET) cohort, a large ethnically diverse group of myopic children. Methods. The COMET enrolled 469 ethnically diverse children aged 6 to younger than 12 years with spherical equivalent refraction between −1.25 and −4.50 diopters (D). Noncycloplegic refraction was measured semiannually for 4 years and annually thereafter. Right eye data were fit to individual Gompertz functions in participants with at least 6 years of follow-up and at least seven refraction measurements over 11 years. Function parameters were estimated using a nonlinear least squares procedure. Associated factors were evaluated using linear regression. Results. In total, 426 participants (91%) had valid Gompertz curve fits. The mean (SD) age at myopia stabilization was 15.61 (4.17) years, and the mean (SD) amount of myopia at stabilization was −4.87 (2.01) D. Ethnicity (P < 0.0001) but not sex or the number of myopic parents was associated with the age at stabilization. Ethnicity (P = 0.02) and the number of myopic parents (P = 0.01) but not sex were associated with myopia magnitude at stabilization. At stabilization, African Americans were youngest (mean age, 13.82 years) and had the least myopia (mean, −4.36 D). Participants with two versus no myopic parents had approximately 1.00 D more myopia at stabilization. The age and the amount of myopia at stabilization were correlated (r = −0.60, P < 0.0001). Conclusions. The Gompertz function provides estimates of the age and the amount of myopia at stabilization in an ethnically diverse cohort. These findings should provide guidance on the time course of myopia and on decisions regarding the type and timing of interventions. PMID:24159085

  20. Correction of temperature-induced spectral variations by loading space standardization.

    PubMed

    Chen, Zeng-Ping; Morris, Julian; Martin, Elaine

    2005-03-01

    With a view to maintaining the validity of multivariate calibration models for chemical processes affected by temperature fluctuations, loading space standardization (LSS) is proposed. Through the application of LSS, multivariate calibration models built at temperatures other than those of the test samples can provide predictions with an accuracy comparable to the results obtained at a constant temperature. Compared with other methods, designed for the same purpose, such as continuous piecewise direct standardization, LSS has the advantages of straightforward implementation and good performance. The methodology was applied to shortwave NIR spectral data sets measured at different temperatures. The results showed that LSS can effectively remove the influence of temperature variations on the spectra and maintain the predictive abilities of the multivariate calibration models.

  1. Measuring bioconcentration factors in fish using exposure to multiple chemicals and internal benchmarking to correct for growth dilution.

    PubMed

    Adolfsson-Erici, Margaretha; Åkerman, Gun; McLachlan, Michael S

    2012-08-01

    Modern chemical legislation requires measuring the bioconcentration factor (BCF) of large numbers of chemicals in fish. The BCF must be corrected for growth dilution, because fish growth rates vary between laboratories. Two hypotheses were tested: (1) that BCFs of multiple chemicals can be measured simultaneously in one experiment, and (2) that internal benchmarking using a conservative test substance in the chemical mixture can be used to correct for growth dilution. Bioconcentration experiments were conducted following major elements of the OECD 305 guideline. Fish were simultaneously exposed to 11 chemicals selected to cover a range of BCFs and susceptibility to biotransformation. A method was developed to calculate the growth-corrected elimination rate constant from the concentration ratio of the analyte and a benchmarking chemical for which growth dilution dominated other elimination mechanisms. This method was applied to the experimental data using hexachlorobenzene as the benchmarking chemical. The growth dilution correction lowered the apparent elimination rate constants by between 5% and a factor of four for eight chemicals, while for two chemicals the growth-corrected elimination rate constant was not significantly different from zero. The benchmarking method reduced the uncertainty in the elimination rate constant compared to the existing method for growth dilution correction. The BCFs from exposing fish to 10 chemicals at once were consistent with BCF values from single-chemical exposures from the literature, supporting hypothesis 1.

  2. Finite temperature application of the corrected propagator method to reactive dynamics in a condensed-phase environment.

    PubMed

    Gelman, David; Schwartz, Steven D

    2011-01-21

    The recently proposed mixed quantum-classical method is extended to applications at finite temperatures. The method is designed to treat complex systems consisting of a low-dimensional quantum part (the primary system) coupled to a dissipative bath described classically. The method is based on a formalism showing how to systematically correct the approximate zeroth-order evolution rule. The corrections are defined in terms of the total quantum Hamiltonian and are taken to the classical limit by introducing the frozen Gaussian approximation for the bath degrees of freedom. The evolution of the primary system is governed by the corrected propagator yielding the exact quantum dynamics. The method has been tested on a standard model system describing proton transfer in a condensed-phase environment: a symmetric double-well potential bilinearly coupled to a bath of harmonic oscillators. Flux correlation functions and thermal rate constants have been calculated at two different temperatures for a range of coupling strengths. The results have been compared to the fully quantum simulations of Topaler and Makri [J. Chem. Phys. 101, 7500 (1994)] with the real path integral method. PMID:21261332

  3. Finite temperature application of the corrected propagator method to reactive dynamics in a condensed-phase environment

    PubMed Central

    Gelman, David; Schwartz, Steven D.

    2011-01-01

    The recently proposed mixed quantum-classical method is extended to applications at finite temperatures. The method is designed to treat complex systems consisting of a low-dimensional quantum part (the primary system) coupled to a dissipative bath described classically. The method is based on a formalism showing how to systematically correct the approximate zeroth-order evolution rule. The corrections are defined in terms of the total quantum Hamiltonian and are taken to the classical limit by introducing the frozen Gaussian approximation for the bath degrees of freedom. The evolution of the primary system is governed by the corrected propagator yielding the exact quantum dynamics. The method has been tested on a standard model system describing proton transfer in a condensed-phase environment: a symmetric double-well potential bilinearly coupled to a bath of harmonic oscillators. Flux correlation functions and thermal rate constants have been calculated at two different temperatures for a range of coupling strengths. The results have been compared to the fully quantum simulations of Topaler and Makri [J. Chem. Phys. 101, 7500 (1994)] with the real path integral method. PMID:21261332

  4. Temperature variation of the structure factor of liquid helium

    NASA Astrophysics Data System (ADS)

    Isihara, A.

    1981-07-01

    The temperature variation of the structure factor S( q) of liquid helium follows S(q) = h̷2q 2{{1 + 2f(ɛ)}}/{2}mɛ , where f(ɛ) is the Bose distribution function of the quasiparticles of energy ɛ( q). For very low temperatures, the formula predicts that S( q) increases linearly with q starting from a constant, S(0) = {kT}/{mc 2}. This trend changes at temperatures higher than T I = {c h̷}/{k}√24δ 1, where δ 1 is the coefficient to q2 of the energy dispersion relation. Therefore, above around 2.78 K, a minimum of S( q) is expected. These theoretical predictions are in good agreement with the recent experimental data of Sears, Svensson, Woods and Martel based on neutron diffraction and of Hallock obtained by X-ray scattering.

  5. TU-F-BRE-06: Flattening-Filter-Free Beam Quality Correction Factor Determination Using Experimental and Monte Carlo Methods

    SciTech Connect

    Wood, M; Desai, V; Simiele, E; Taneja, S; DeWerd, L

    2014-06-15

    Purpose: To investigate beam quality correction factors for the flattening-filter-free (FFF) energies of the TrueBeam™ accelerator based on a dosimetry formalism for small and nonstandard fields. Methods: Three detectors - an Exradin W1 scintillator, Sun Nuclear EDGE diode, and LiF(Mg,Tl) TLD-100 chips - were investigated to determine their applicability as tools to measure quality correction factors for ionization chambers in the small and nonstandard fields of the TrueBeam™. Volume-averaging effects and energy dependence were observed in fields ranging from 1×1 to 40×40 cm{sup 2} for 6 MV and 10 MV beam energies using both FFF and flattened beam modes. Correction factors were determined for three ionization chambers: an Exradin A12 Farmer-type chamber, an Exradin A1SL scanning chamber, and an Exradin A26 reference-class microchamber. Beam quality corrections were also obtained using a benchmarked model of the TrueBeam™ created with the BEAMnrc user code of EGSnrc. Results: All three detectors demonstrated measureable energy dependence in the megavoltage range. The EDGE diode was deemed the most appropriate tool for beam quality correction factor measurements due to its low energy dependence and small size; however, alanine will be used in the future to reduce energy dependent effects even further. Measured k{sub Qmsr,Q} corrections of up to 4% were found for the 6MV FFF and 10 MV FFF beams, corresponding to a discrepancy of up to 3% compared to TG-51-determined dose. Up to a 10% k{sub Qclin,Qmsr} correction was measured for small fields referenced to a 10×10 cm{sup 2} field of the same energy. Much larger corrections were determined using the Monte Carlo model, and these discrepancies require further investigation. Conclusion: Progress has been made toward determining beam quality correction factors for the small and nonstandard fields of the TrueBeam™ accelerator. Further work must be done to ensure greater accuracy in patient treatments with this new

  6. Burnout, Job Stress and Job Satisfaction Among Southern Correctional Officers: Perceptions and Causal Factors.

    ERIC Educational Resources Information Center

    Lindquist, Charles A.; Whitehead, John T.

    1986-01-01

    Surveyed perceptions of burnout, job stress, and job satisfaction among a representative sample (N=241) of Alabama correctional officers. Examination of predictor variables revealed that social support; marital status; role conflict; age; correctional seniority; and extrinsic, organizational, and overload stressors significantly influenced…

  7. Single-image-based solution for optics temperature-dependent nonuniformity correction in an uncooled long-wave infrared camera.

    PubMed

    Cao, Yanpeng; Tisse, Christel-Loic

    2014-02-01

    In this Letter, we propose an efficient and accurate solution to remove temperature-dependent nonuniformity effects introduced by the imaging optics. This single-image-based approach computes optics-related fixed pattern noise (FPN) by fitting the derivatives of correction model to the gradient components, locally computed on an infrared image. A modified bilateral filtering algorithm is applied to local pixel output variations, so that the refined gradients are most likely caused by the nonuniformity associated with optics. The estimated bias field is subtracted from the raw infrared imagery to compensate the intensity variations caused by optics. The proposed method is fundamentally different from the existing nonuniformity correction (NUC) techniques developed for focal plane arrays (FPAs) and provides an essential image processing functionality to achieve completely shutterless NUC for uncooled long-wave infrared (LWIR) imaging systems.

  8. Recovery and radiation corrections and time constants of several sizes of shielded and unshielded thermocouple probes for measuring gas temperature

    NASA Technical Reports Server (NTRS)

    Glawe, G. E.; Holanda, R.; Krause, L. N.

    1978-01-01

    Performance characteristics were experimentally determined for several sizes of a shielded and unshielded thermocouple probe design. The probes are of swaged construction and were made of type K wire with a stainless steel sheath and shield and MgO insulation. The wire sizes ranged from 0.03- to 1.02-mm diameter for the unshielded design and from 0.16- to 0.81-mm diameter for the shielded design. The probes were tested through a Mach number range of 0.2 to 0.9, through a temperature range of room ambient to 1420 K, and through a total-pressure range of 0.03 to 0.2.2 MPa (0.3 to 22 atm). Tables and graphs are presented to aid in selecting a particular type and size. Recovery corrections, radiation corrections, and time constants were determined.

  9. Finite-size corrections to scaling of the magnetization distribution in the two-dimensional XY model at zero temperature.

    PubMed

    Palma, G; Niedermayer, F; Rácz, Z; Riveros, A; Zambrano, D

    2016-08-01

    The zero-temperature, classical XY model on an L×L square lattice is studied by exploring the distribution Φ_{L}(y) of its centered and normalized magnetization y in the large-L limit. An integral representation of the cumulant generating function, known from earlier works, is used for the numerical evaluation of Φ_{L}(y), and the limit distribution Φ_{L→∞}(y)=Φ_{0}(y) is obtained with high precision. The two leading finite-size corrections Φ_{L}(y)-Φ_{0}(y)≈a_{1}(L)Φ_{1}(y)+a_{2}(L)Φ_{2}(y) are also extracted both from numerics and from analytic calculations. We find that the amplitude a_{1}(L) scales as ln(L/L_{0})/L^{2} and the shape correction function Φ_{1}(y) can be expressed through the low-order derivatives of the limit distribution, Φ_{1}(y)=[yΦ_{0}(y)+Φ_{0}^{'}(y)]^{'}. Thus, Φ_{1}(y) carries the same universal features as the limit distribution and can be used for consistency checks of universality claims based on finite-size systems. The second finite-size correction has an amplitude a_{2}(L)∝1/L^{2} and one finds that a_{2}Φ_{2}(y)≪a_{1}Φ_{1}(y) already for small system size (L>10). We illustrate the feasibility of observing the calculated finite-size corrections by performing simulations of the XY model at low temperatures, including T=0. PMID:27627284

  10. Allometric Scaling of Therapeutic Monoclonal Antibodies Using Antigen Concentration as a Correction Factor: Application to the Human Clearance Prediction.

    PubMed

    Wang, Lei; Qiang, Wei; Cheng, Zeneng

    2016-03-01

    Allometric scaling has been widely used for predictions of human pharmacokinetic (PK) parameters in the development of monoclonal antibody (mAb) drugs, and some correction factors have been proposed to improve the estimations. However, classic correction factors fail to offer a complete explanation of the additional differences among species besides the body weight and, thus, lack enough power to further improve the predictions. In this study, the antigen concentration was initially set as a new correction factor to predict the human clearance (CL) of mAbs. Bevacizumab was intravenously injected into 2 animal species and humans to obtain PK data to predict human CL from the animal data. Additionally, a new approach was also validated with data from 3 other mAbs which were collected through a literature review of published work. Accordingly, allometric scaling with a correction factor of the antigen concentration generated accurate estimations of the human CL of 4 mAbs, which were superior to the results obtained by other classic scaling methods. More importantly, the proposed method also achieved good predictions of individual human CL of bevacizumab. In conclusion, the potential of this method as a powerful tool for human PK estimation of mAbs in species translation has been demonstrated. PMID:26886347

  11. Temperature dependence of the electron spin g factor in CdTe and InP

    NASA Astrophysics Data System (ADS)

    Pfeffer, Pawel; Zawadzki, Wlodek

    2012-04-01

    Temperature dependence of the electron spin g factors in bulk CdTe and InP is calculated and compared with experiment. It is assumed that the only modification of the band structure related to temperature is a dilatation change in the fundamental energy gap. The dilatation changes of fundamental gaps are calculated for both materials using available experimental data. Computations of the band structures in the presence of a magnetic field are carried out employing five-level P.p model appropriate for medium-gap semiconductors. In particular, the model takes into account spin splitting due to bulk inversion asymmetry (BIA) of the materials. The resulting theoretical effective masses and g factors increase with electron energy due to band nonparabolicity. Average g values are calculated by summing over populated Landau and spin levels properly accounting for the thermal distribution of electrons in the band. It is shown that the spin splitting due to BIA in the presence of a magnetic field gives observable contributions to g values. Our calculations are in good agreement with experiments in the temperature range of 0 K to 300 K for CdTe and 0 K to 180 K for InP. The temperature dependence of g is stronger in CdTe than in InP due to different signs of band-edge g values in the two materials. Good agreement between the theory and experiments strongly indicates that the temperature dependence of spin g factors is correctly explained. In addition, we discuss formulas for the energy dependence of spin g factor due to band nonparabolicity, which are liable to misinterpretation.

  12. Evaluation of Size Correction Factor for Size-specific Dose Estimates (SSDE) Calculation.

    PubMed

    Mizonobe, Kazufusa; Shiraishi, Yuta; Nakano, Satoshi; Fukuda, Chiaki; Asanuma, Osamu; Harada, Kohei; Date, Hiroyuki

    2016-09-01

    American Association of Physicists in Medicine (AAPM) Report No.204 recommends the size-specific dose estimates (SSDE), wherein SSDE=computed tomography dose index-volume (CTDIvol )×size correction factor (SCF), as an index of the CT dose to consider patient thickness. However, the study on SSDE has not been made yet for area detector CT (ADCT) device such as a 320-row CT scanner. The purpose of this study was to evaluate the SCF values for ADCT by means of a simulation technique to look into the differences in SCF values due to beam width. In the simulation, to construct the geometry of the Aquilion ONE X-ray CT system (120 kV), the dose ratio and the effective energies were measured in the cone angle and fan angle directions, and these were incorporated into the simulation code, Electron Gamma Shower Ver.5 (EGS5). By changing the thickness of a PMMA phantom from 8 cm to 40 cm, CTDIvol and SCF were determined. The SCF values for the beam widths in conventional and volume scans were calculated. The differences among the SCF values of conventional, volume scans, and AAPM were up to 23.0%. However, when SCF values were normalized in a phantom of 16 cm diameter, the error tended to decrease for the cases of thin body thickness, such as those of children. It was concluded that even if beam width and device are different, the SCF values recommended by AAPM are useful in clinical situations. PMID:27647595

  13. Correction factors for ionization chamber dosimetry in CyberKnife: Machine-specific, plan-class, and clinical fields

    SciTech Connect

    Gago-Arias, Araceli; Antolin, Elena; Fayos-Ferrer, Francisco; Simon, Rocio; Gonzalez-Castano, Diego M.; Palmans, Hugo; Sharpe, Peter; Gomez, Faustino; Pardo-Montero, Juan

    2013-01-15

    Purpose: The aim of this work is the application of the formalism for ionization chamber reference dosimetry of small and nonstandard fields [R. Alfonso, P. Andreo, R. Capote, M. S. Huq, W. Kilby, P. Kjaell, T. R. Mackie, H. Palmans, K. Rosser, J. Seuntjens, W. Ullrich, and S. Vatnitsky, 'A new formalism for reference dosimetry of small and nonstandard fields,' Med. Phys. 35, 5179-5186 (2008)] to the CyberKnife robotic radiosurgery system. Correction factors for intermediate calibration fields, a machine-specific reference field (msr) and two plan-class specific reference fields (pcsr), have been studied. Furthermore, the applicability of the new formalism to clinical dosimetry has been analyzed through the investigation of two clinical treatments. Methods: PTW31014 and Scanditronix-Wellhofer CC13 ionization chamber measurements were performed for the fields under investigation. Absorbed dose to water was determined using alanine reference dosimetry, and experimental correction factors were calculated from alanine to ionization chamber readings ratios. In addition, correction factors were calculated for the intermediate calibration fields and one of the clinical treatment fields using the Monte Carlo method and these were compared with the experimental values. Results: Overall correction factors deviating from unity by approximately 2% were obtained from both measurements and simulations, with values below and above unity for the studied intermediate calibration fields and clinical fields for the ionization chambers under consideration. Monte Carlo simulations yielded correction factors comparable with those obtained from measurements for the machine-specific reference field, although differences from 1% to 3.3% were observed between measured and calculated correction factors for the composite intermediate calibration fields. Dose distribution inhomogeneities are thought to be responsible for such discrepancies. Conclusions: The differences found between overall

  14. Quantum corrections to resistance of microblock tellurium at ultralow temperatures under phonon freezing conditions

    SciTech Connect

    Farbshtein, I. I. Chernyaev, A. V.; Shamshur, D. V.; Averkiev, N. S.

    2010-08-15

    The low-temperature magnetoresistance of bulk tellurium samples with a microcrystalline structure is investigated. At ultralow temperatures T {<=} 1 K, an anomalous positive magnetoresistance (APMR), viz. the antilocalization effect, is observed. It is shown that this effect can be explained using the weak localization theory. The characteristic parameters of the theory are determined. It is concluded that charge carriers produce a predominant effect on the phase breakdown time in the APMR mode of elastic scattering from structure defects, which leads to intervalley transitions without spin flip.

  15. Sci—Fri AM: Mountain — 01: Validation of a new formulism and the related correction factors on output factor determination for small photon fields

    SciTech Connect

    Wang, Yizhen; Younge, Kelly; Nielsen, Michelle; Mutanga, Theodore; Cui, Congwu; Das, Indra J.

    2014-08-15

    Small field dosimetry measurements including output factors are difficult due to lack of charged-particle equilibrium, occlusion of the radiation source, the finite size of detectors, and non-water equivalence of detector components. With available detectors significant variations could be measured that will lead to incorrect delivered dose to patients. IAEA/AAPM have provided a framework and formulation to correct the detector response in small photon fields. Monte Carlo derived correction factors for some commonly used small field detectors are now available, however validation has not been performed prior to this study. An Exradin A16 chamber, EDGE detector and SFD detector were used to perform the output factor measurement for a series of conical fields (5–30mm) on a Varian iX linear accelerator. Discrepancies up to 20%, 10% and 6% were observed for 5, 7.5 and 10 mm cones between the initial output factors measured by the EDGE detector and the A16 ion chamber, while the discrepancies for the conical fields larger than 10 mm were less than 4%. After the application of the correction, the output factors agree well with each other to within 1%. Caution is needed when determining the output factors for small photon fields, especially for fields 10 mm in diameter or smaller. More than one type of detector should be used, each with proper corrections applied to the measurement results. It is concluded that with the application of correction factors to appropriately chosen detectors, output can be measured accurately for small fields.

  16. Correction factors for on-line microprobe analysis of multielement alloy systems

    NASA Technical Reports Server (NTRS)

    Unnam, J.; Tenney, D. R.; Brewer, W. D.

    1977-01-01

    An on-line correction technique was developed for the conversion of electron probe X-ray intensities into concentrations of emitting elements. This technique consisted of off-line calculation and representation of binary interaction data which were read into an on-line minicomputer to calculate variable correction coefficients. These coefficients were used to correct the X-ray data without significantly increasing computer core requirements. The binary interaction data were obtained by running Colby's MAGIC 4 program in the reverse mode. The data for each binary interaction were represented by polynomial coefficients obtained by least-squares fitting a third-order polynomial. Polynomial coefficients were generated for most of the common binary interactions at different accelerating potentials and are included. Results are presented for the analyses of several alloy standards to demonstrate the applicability of this correction procedure.

  17. Physical factors in cataractogenesis: ambient ultraviolet radiation and temperature

    SciTech Connect

    Sliney, D.H.

    1986-05-01

    A number of environmental cofactors have been implicated in cataracto-genesis. Two have received the greatest attention: ultraviolet radiation (UVR) and ambient temperature. Unfortunately, both temperature and UVR levels vary similarly with geographical latitude. Careful attention to several more refined physical variables and the geometry of exposure may permit investigators to separate the contributory effects of these two physical agents. This paper briefly reviews the available data, estimates the variation of lenticular temperature with ambient temperature, and provides measurements of short-wavelength (UV-B) UVR exposure to the human eye with different meterological conditions. The study attempts to provide epidemiological investigators with more detailed information necessary to perform more accurate studies of cataract and other ocular pathologies that appear to be related to environmental factors. Ocular UV-B radiation exposure levels were measured at nine locations in the USA near 40 degrees latitude at elevations from sea level to 8000 ft. Terrain reflectance is shown to be much more important than terrain elevation; cloud cover and haze may actually increase ocular exposure; and the value of wearing brimmed hats and spectacles varies with the environment. Several avenues for future research are suggested.

  18. Small SWaP TEC-less SWIR camera with current mirror pixel and temperature dependent non-uniformity corrections

    NASA Astrophysics Data System (ADS)

    Nazemi, Jonathan; Brubaker, Robert

    2016-05-01

    Previously, we have reported on advances made with our CTIA based TEC-less SWIR cameras [1, 2, 3, 4]. Here, we present our next generation TEC-less small SWaP SWIR cameras which are built upon a current mirror type pixel. The standard packaged FPAs are modified by replacing the TECs with copper shims. These FPAs are incorporated into cameras with similar electronics to our COTS cameras (CSX and JSX series), and then fully characterized from -30 °C to 60 °C. From these data, we developed algorithms that provide temperature-based corrections resulting in nonuniformity of approximately 0.5 % over the entire operating temperature. Additionally, over this range, the 640 x 512 resolution camera exhibited power consumption in the 1.2-1.3 W range, whereas the 1280 x 1024 camera exhibited power consumption in the 1.3-1.4 W range.

  19. Temperature and salinity correction coefficients for light absorption by water in the visible to infrared spectral region.

    PubMed

    Röttgers, Rüdiger; McKee, David; Utschig, Christian

    2014-10-20

    The light absorption coefficient of water is dependent on temperature and concentration of ions, i.e. the salinity in seawater. Accurate knowledge of the water absorption coefficient, a, and/or its temperature and salinity correction coefficients, Ψ(T) and Ψ(S), respectively, is essential for a wide range of optical applications. Values are available from published data only at specific narrow wavelength ranges or at single wavelengths in the visible and infrared regions. Ψ(T) and Ψ(S) were therefore spectrophotometrically measured throughout the visible, near, and short wavelength infrared spectral region (400 to ~2700 nm). Additionally, they were derived from more precise measurements with a point-source integrating-cavity absorption meter (PSICAM) for 400 to 700 nm. When combined with earlier measurements from the literature in the range of 2600 - 14000 nm (wavenumber: 3800 - 700 cm(-1)), the coefficients are provided for 400 to 14000 nm (wavenumber: 25000 to 700 cm(-1)).

  20. Fatigue Crack Growth Rate and Stress-Intensity Factor Corrections for Out-of-Plane Crack Growth

    NASA Technical Reports Server (NTRS)

    Forth, Scott C.; Herman, Dave J.; James, Mark A.

    2003-01-01

    Fatigue crack growth rate testing is performed by automated data collection systems that assume straight crack growth in the plane of symmetry and use standard polynomial solutions to compute crack length and stress-intensity factors from compliance or potential drop measurements. Visual measurements used to correct the collected data typically include only the horizontal crack length, which for cracks that propagate out-of-plane, under-estimates the crack growth rates and over-estimates the stress-intensity factors. The authors have devised an approach for correcting both the crack growth rates and stress-intensity factors based on two-dimensional mixed mode-I/II finite element analysis (FEA). The approach is used to correct out-of-plane data for 7050-T7451 and 2025-T6 aluminum alloys. Results indicate the correction process works well for high DeltaK levels but fails to capture the mixed-mode effects at DeltaK levels approaching threshold (da/dN approximately 10(exp -10) meter/cycle).

  1. Solid state temperature-dependent NUC (non-uniformity correction) in uncooled LWIR (long-wave infrared) imaging system

    NASA Astrophysics Data System (ADS)

    Cao, Yanpeng; Tisse, Christel-Loic

    2013-06-01

    In uncooled LWIR microbolometer imaging systems, temperature fluctuations of FPA (Focal Plane Array) as well as lens and mechanical components placed along the optical path result in thermal drift and spatial non-uniformity. These non-idealities generate undesirable FPN (Fixed-Pattern-Noise) that is difficult to remove using traditional, individual shutterless and TEC-less (Thermo-Electric Cooling) techniques. In this paper we introduce a novel single-image based processing approach that marries the benefits of both statistical scene-based and calibration-based NUC algorithms, without relying neither on extra temperature reference nor accurate motion estimation, to compensate the resulting temperature-dependent non-uniformities. Our method includes two subsequent image processing steps. Firstly, an empirical behavioral model is derived by calibrations to characterize the spatio-temporal response of the microbolometric FPA to environmental and scene temperature fluctuations. Secondly, we experimentally establish that the FPN component caused by the optics creates a spatio-temporally continuous, low frequency, low-magnitude variation of the image intensity. We propose to make use of this property and learn a prior on the spatial distribution of natural image gradients to infer the correction function for the entire image. The performance and robustness of the proposed temperature-adaptive NUC method are demonstrated by showing results obtained from a 640×512 pixels uncooled LWIR microbolometer imaging system operating over a broad range of temperature and with rapid environmental temperature changes (i.e. from -5°C to 65°C within 10 minutes).

  2. A Fourier approach for estimating and correcting the topographic perturbation of low-temperature thermochronological data

    NASA Astrophysics Data System (ADS)

    Glotzbach, C.; Braun, J.; van der Beek, P.

    2015-05-01

    Thermochronology is a unique tool to reconstruct the long-term exhumation history of outcropping rocks. Pronounced (palaeo-) topography can markedly perturb near-surface isotherms, which can result in erroneous exhumation histories derived from age-elevation relationships but also offers the possibility to reconstruct palaeo-topography. Here we use a synthetic dataset to illustrate the complex non-linear relationships between the degree of topographic perturbation of thermochronological ages on one hand, and exhumation rate, geothermal gradient, and topographic wavelength and relief on the other. The dataset reveals that, in theory, relief changes can be retrieved for wavelengths as low as 5 km, and wavelength changes are possible to detect for relief as low as 0.5 km. In addition, the data attest that even in regions characterised by very slow exhumation rates (e.g. 0.03 km/Ma), changes in palaeo-topography can be successfully retrieved. Coupling of this dataset with a Fast Fourier Transform (FFT) algorithm to decompose complex 2D topography into sinusoidal functions allows a rapid and accurate estimation of the topographic perturbation and resulting thermochronological ages assuming steady-state exhumation. This coupled method was successfully implemented to (i) predict most promising sample sites for the estimation of palaeo-topography and (ii) correct exhumation rates derived from non-vertical age-elevation profiles.

  3. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in degrees...

  4. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in degrees...

  5. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in...

  6. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in...

  7. 49 CFR 192.115 - Temperature derating factor (T) for steel pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Temperature derating factor (T) for steel pipe... § 192.115 Temperature derating factor (T) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105 is determined as follows: Gas temperature in...

  8. Real-time prediction of ground motion using real-time correction of site amplification factors for EEW

    NASA Astrophysics Data System (ADS)

    Aoki, S.; Hoshiba, M.

    2013-12-01

    1. Introduction Hoshiba(2013a, JGR) proposed a method for prediction of ground motion based on real-time monitoring, in which hypocenter and M are not required. In this method, site amplification must be corrected in real-time manner. Hoshiba (2013b, BSSA) developed a causal recursive digital filter in the time domain for the real-time correction of frequency-dependent site factors. In this presentation we will apply this correction by using the site factors estimated by the spectral ratio method. 2. Method of site correction When the epicentral distances r to a station-pair (site 1 and 2) are much larger than the distance d between those sites, the averaged spectral ratio of S waves from many events can be regarded as the relative site factor between site 1 and 2 in the spectral ratio method. In this study, the dataset, which consists of the station-pairs and events that occurred in the area around Japan from 1996 to 2010, are selected to satisfy the conditions of 100km≦r≦350km and d≦30km, and we design the causal digital filter having similar amplitude property to relative site factor for the station-pair. The filter parameters are estimated by minimizing the residuals between the frequency-dependent site factor and modeled amplitude spectrum in the frequency range between 0.1 and 20Hz. In order to examine the effect of this method, we compare the results of following two methods for the prediction of the JMA seismic intensity. We want to focus on only site effect in this examination, so that the above-mentioned dataset is analyzed. Method A (MA): Seismic intensities at site 2 are predicted from waveforms observed at site 1 by using the correction for frequency-dependent site factors. Here, for each event the 3-componet waveforms at site 2 are first simulated from those at site 1 applying the causal filter, and then the predicted seismic intensity is calculated from the simulated waveforms by the method of Kunugi et al. (2008). Method B (MB

  9. Determinations of the correction factors for small fields in cylindrical ionization chambers based on measurement and numerical calculation

    NASA Astrophysics Data System (ADS)

    Park, Kwangwoo; Choi, Wonhoon; Park, Sungho; Choi, Jin Hwa; Park, Suk Won; Bak, Jino

    2015-07-01

    We investigated the volume averaging effect for air-filled cylindrical ionization chambers to determine the correction factors in a small photon field for a given chamber. We measured output factors with several cylindrical ionization chambers, and by using a mathematical method similar to deconvolution, we modeled the non-constant and inhomogeneous exposure function in the cavity of the chamber. The parameters in the exposure function and the correction factors were determined by solving a system of equations that we had developed by using the measured data and the geometry of the given chamber. The correction factors (CFs) were very similar to those obtained from Monte Carlo (MC) simulations. For example, the CFs in this study were found to be 1.116 for PTW31010 and 1.0225 for PTW31016 while the CFs obtained from MC simulations were reported as being approximately between 1.17 and 1.20 for PTW31010 and between 1.02 and 1.06 for PTW31016 in a 6-MV photon beam of 1 × 1 cm2. Furthermore, the method of deconvolution combined with the MC result for the chamber's response function showed a similar CF for PTW 30013, which was reported as 2.29 and 1.54 for a 1 × 1 cm2 and a 1.5 × 1.5 cm2 field size, respectively. The CFs from our method were similar, 2.42 and 1.54. In addition, we report CFs for PTW30013, PTW31010, PTW31016, IBA FC23-C, and IBA CC13. As a consequence, we suggest the use of our method to measure the correct output factor by using the fact that an inhomogeneous exposure causes a volume averaging effect in the cavity of air-filled cylindrical ionization chamber. The result obtained by using our method is very similar to that obtained from MC simulations. The method we developed can easily be applied in clinics.

  10. The replacement correction factor for the BIPM flat cavity ion chamber and the value of W/e

    SciTech Connect

    Wang, L. L. W.; Rogers, D. W. O.

    2008-10-15

    A graphite flat cavity ionization chamber is used at the BIPM in France to determine the absorbed dose to graphite in a {sup 60}Co photon beam and thereby used to determine the product of the value of W/e, the average energy required to produce an ion pair in dry air, and the value of (L{sub {Delta}}/{rho}){sub a}{sup C}, the mean restricted mass collision stopping-power ratio for graphite to air in a {sup 60}Co beam. The accuracy of the (W/e) (L{sub {Delta}}/{rho}){sub a}{sup C} value thus determined depends upon the accuracy of the perturbation correction factors adopted for this chamber. The perturbation effect of this chamber was accounted for by the replacement correction factor whose value was calculated by an analytical method and confirmed by an EGS4 Monte Carlo calculation. The purpose of this study is to investigate the validity of the analytical and the EGS4 calculations by using recently established methods and the EGSnrc Monte Carlo code, a much improved version of EGS4, to calculate the replacement correction factors for the graphite chamber. It is found that the replacement correction factors used for the BIPM chamber are not correct: the values used are smaller than they should be by about 1%. This leads to a 1% overestimation of the (W/e) (L{sub {Delta}}/{rho}){sub a}{sup C} value determined by using this chamber. This implies that {sup 60}Co air kerma standards that are directly proportional to this product need to be reduced by 1%. Based on the values of the replacement correction factors calculated in this study, and on the value of (L{sub {Delta}}/{rho}){sub a}{sup C} evaluated from ICRU Report No. 37 stopping power for graphite, the value of W/e determined by using the BIPM chamber should be 33.61{+-}0.08 J/C. If a more recent value of mean excitation energy for graphite (86.8 eV) and grain density are used to evaluate the graphite stopping power, then the value obtained for W/e is 34.15{+-}0.08 J/C.

  11. Experimental determination of field factors ([Formula: see text]) for small radiotherapy beams using the daisy chain correction method.

    PubMed

    Lárraga-Gutiérrez, José Manuel

    2015-08-01

    Recently, Alfonso et al proposed a new formalism for the dosimetry of small and non-standard fields. The proposed new formalism is strongly based on the calculation of detector-specific beam correction factors by Monte Carlo simulation methods, which accounts for the difference in the response of the detector between the small and the machine specific reference field. The correct calculation of the detector-specific beam correction factors demands an accurate knowledge of the linear accelerator, detector geometry and composition materials. The present work shows that the field factors in water may be determined experimentally using the daisy chain correction method down to a field size of 1 cm × 1 cm for a specific set of detectors. The detectors studied were: three mini-ionization chambers (PTW-31014, PTW-31006, IBA-CC01), three silicon-based diodes (PTW-60018, IBA-SFD and IBA-PFD) and one synthetic diamond detector (PTW-60019). Monte Carlo simulations and experimental measurements were performed for a 6 MV photon beam at 10 cm depth in water with a source-to-axis distance of 100 cm. The results show that the differences between the experimental and Monte Carlo calculated field factors are less than 0.5%-with the exception of the IBA-PFD-for field sizes between 1.5 cm × 1.5 cm and 5 cm × 5 cm. For the 1 cm × 1 cm field size, the differences are within 2%. By using the daisy chain correction method, it is possible to determine measured field factors in water. The results suggest that the daisy chain correction method is not suitable for measurements performed with the IBA-PFD detector. The latter is due to the presence of tungsten powder in the detector encapsulation material. The use of Monte Carlo calculated [Formula: see text] is encouraged for field sizes less than or equal to 1 cm × 1 cm for the dosimeters used in this work. PMID:26161448

  12. Critical Factors in Mental Health Programming for Juveniles in Corrections Facilities

    ERIC Educational Resources Information Center

    Underwood, Lee A.; Phillips, Annie; von Dresner, Kara; Knight, Pamela D.

    2006-01-01

    Juveniles with mental health and other specialized needs are overrepresented in the juvenile justice system, and while juvenile corrections have not historically provided standardized and evidence-based mental health services for its incarcerated youth, the demand is evident. The reality is that juveniles with serious mental illness are committed…

  13. Method to determine the position-dependant metal correction factor for dose-rate equivalent laser testing of semiconductor devices

    DOEpatents

    Horn, Kevin M.

    2013-07-09

    A method reconstructs the charge collection from regions beneath opaque metallization of a semiconductor device, as determined from focused laser charge collection response images, and thereby derives a dose-rate dependent correction factor for subsequent broad-area, dose-rate equivalent, laser measurements. The position- and dose-rate dependencies of the charge-collection magnitude of the device are determined empirically and can be combined with a digital reconstruction methodology to derive an accurate metal-correction factor that permits subsequent absolute dose-rate response measurements to be derived from laser measurements alone. Broad-area laser dose-rate testing can thereby be used to accurately determine the peak transient current, dose-rate response of semiconductor devices to penetrating electron, gamma- and x-ray irradiation.

  14. Small field diode correction factors derived using an air core fibre optic scintillation dosimeter and EBT2 film

    NASA Astrophysics Data System (ADS)

    Ralston, Anna; Liu, Paul; Warrener, Kirbie; McKenzie, David; Suchowerska, Natalka

    2012-05-01

    There is no commercially available real-time dosimeter that can accurately measure output factors for field sizes down to 4 mm without the use of correction factors. Silicon diode detectors are commonly used but are not dosimetrically water equivalent, resulting in energy dependence and fluence perturbation. In contrast, plastic scintillators are nearly dosimetrically water equivalent. A fibre optic dosimeter (FOD) with a 0.8 mm3 plastic scintillator coupled to an air core light guide was used to measure the output factors for Novalis/BrainLab stereotactic cones of diameter 4-30 mm and Novalis MLC fields of width 5-100 mm. The FOD data matched the output factors measured by a 0.125 cm3 Semiflex ion chamber for the MLC fields above 30 mm and those measured with the EBT2 radiochromic film for the cones and MLC fields below 30 mm. Relative detector readings were obtained with four diode types (IBA SFD, EFD, PFD, PTW 60012) for the same fields. Empirical diode correction factors were determined by taking the ratio of FOD output factors to diode relative detector readings. The diodes were found to over-respond by 3%-16% for the smallest field. There was good agreement between different diodes of the same model number.

  15. Monte Carlo calculation of beam quality correction factors in proton beams using detailed simulation of ionization chambers

    NASA Astrophysics Data System (ADS)

    Gomà, Carles; Andreo, Pedro; Sempau, Josep

    2016-03-01

    This work calculates beam quality correction factors (k Q ) in monoenergetic proton beams using detailed Monte Carlo simulation of ionization chambers. It uses the Monte Carlo code penh and the electronic stopping powers resulting from the adoption of two different sets of mean excitation energy values for water and graphite: (i) the currently ICRU 37 and ICRU 49 recommended {{I}\\text{w}}=75~\\text{eV} and {{I}\\text{g}}=78~\\text{eV} and (ii) the recently proposed {{I}\\text{w}}=78~\\text{eV} and {{I}\\text{g}}=81.1~\\text{eV} . Twelve different ionization chambers were studied. The k Q factors calculated using the two different sets of I-values were found to agree with each other within 1.6% or better. k Q factors calculated using current ICRU I-values were found to agree within 2.3% or better with the k Q factors tabulated in IAEA TRS-398, and within 1% or better with experimental values published in the literature. k Q factors calculated using the new I-values were also found to agree within 1.1% or better with the experimental values. This work concludes that perturbation correction factors in proton beams—currently assumed to be equal to unity—are in fact significantly different from unity for some of the ionization chambers studied.

  16. Conversion and correction factors for historical measurements of Iodine-131 in Hanford-area vegetation, 1945--1947: Draft

    SciTech Connect

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-05-01

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy's (DOE) Hanford Site near Richland, Washington. The report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947.

  17. Analysis and design of modular three-phase power factor correction schemes for utility interface

    NASA Astrophysics Data System (ADS)

    Hahn, Jae-Hong

    The extensive use of non-linear and electronically switched loads in power system has lead to higher incidences of harmonic distortion of the voltage and current waveforms. Harmonic currents degrade power quality and are considered the main source of many system malfunctions. Technical guidelines and standards regarding suppressions of system harmonic contents have been enacted. This dissertation proposes several new three-phase power factor correction (PFC) schemes using single-phase PFC modules. An integrated single-switch approach is first proposed. This is essentially an add-on solution to standard ASD's. This approach is based on circulating third harmonic current between neutral and DC mid-point by utilizing a lossless resistor. Single-phase PFC emulates this resistor to control the amplitude of the current, which is implemented by the dynamic breaking chopper available in standard adjustable speed drives (ASD's). This approach is also capable of reducing harmonic distortion in multiple drives. Analysis, design and simulations are conducted to determine the performance of the proposed scheme with different line impedances and with and without dc-link inductance in the ASD. Experimental results are presented using commercial ASD retrofitted with the proposed approach. Second scheme proposes a three-phase PFC using two standard single-phase PFC modules. In this approach, three-phase input is transformed into two-phase by means of 0.14 pu autotransformer. Two standard single-phase PFC modules are employed to process two-phase power to do output. Split inductors and diodes are employed to limit the interaction between the two phases. A method to eliminate the interaction between phases is also described. Due to cascade operation of two PFC stages, low frequency (120Hz) ripple in dc-link is cancelled. An active interphase transformer (IPT) scheme is proposed to draw sinusoidal input line currents, in the third study. This scheme utilizes a unique combination of a

  18. The effects of geology and the impact of seasonal correction factors on indoor radon levels: a case study approach.

    PubMed

    Gillmore, Gavin K; Phillips, Paul S; Denman, Antony R

    2005-01-01

    Geology has been highlighted by a number of authors as a key factor in high indoor radon levels. In the light of this, this study examines the application of seasonal correction factors to indoor radon concentrations in the UK. This practice is based on an extensive database gathered by the National Radiological Protection Board over the years (small-scale surveys began in 1976 and continued with a larger scale survey in 1988) and reflects well known seasonal variations observed in indoor radon levels. However, due to the complexity of underlying geology (the UK arguably has the world's most complex solid and surficial geology over the shortest distances) and considerable variations in permeability of underlying materials it is clear that there are a significant number of occurrences where the application of a seasonal correction factor may give rise to over-estimated or under-estimated radon levels. Therefore, the practice of applying a seasonal correction should be one that is undertaken with caution, or not at all. This work is based on case studies taken from the Northamptonshire region and comparisons made to other permeable geologies in the UK.

  19. Temperature factor for magnetic instability conditions of type - II superconductors

    NASA Astrophysics Data System (ADS)

    Romanovskii, V.

    2014-10-01

    The macroscopic development of interrelated electrodynamics and thermal states taking place both before and after instability onset in type-II superconductors are studied using the critical state and the flux creep concepts. The physical mechanisms of the non-isothermal formation of the critical state are discussed solving the set of unsteady thermo-electrodynamics equations taking into consideration the unknown moving penetration boundary of the magnetic flux. To make it, the numerical method, which allows to study diffusion phenomena with unknown moving phase-two boundary, is developed. The corresponding non-isothermal flux jump criteria are written. It is proved for the first time that, first, the diffusion phenomena in superconductors have the fission-chain-reaction nature, second, the stability conditions, losses in superconductor and its stable overheating before instability onset are mutually dependent. The results are compared with those following from the existing magnetic instability theory, which does not take into consideration the stable temperature increase of superconductor before the instability onset. It is shown that errors of isothermal approximation are significant for modes closed to adiabatic ones. Therefore, the well-known adiabatic flux jump criterion limits the range of possible stable superconducting states since a correct determination of their stability states must take into account the thermal prehistory of the stable magnetic flux penetration. As a result, the calculation errors in the isothermal approximation will rise when the sweep rate of an external magnetic field or the size of the superconductor’s cross-sectional area increase. The basic conclusions formulated in the framework of the critical state model are verified comparing the experimental results and the numerical analysis of the stability conditions and the temperature dynamics of the helicoid-type superconducting current-carrying element having real voltage

  20. Factors affecting characterization of bulk high-temperature superconductors

    SciTech Connect

    Hull, J.R.

    1997-11-01

    Three major factors affect the characterization of bulk high-temperature superconductors in terms of their levitation properties during interaction with permanent magnets. First, the appropriate parameter for the permanent magnet is internal magnetization, not the value of the magnetic field measured at the magnet`s surface. Second, although levitation force grows with superconductor thickness and surface area, for a given permanent magnet size, comparison of levitation force between samples is meaningful when minimum values are assigned to the superconductor size parameters. Finally, the effect of force creep must be considered when time-averaging the force measurements. In addition to levitational force, the coefficient of friction of a levitated rotating permanent magnet may be used to characterize the superconductor.

  1. SU-E-T-464: On the Equivalence of the Quality Correction Factor for Pencil Beam Scanning Proton Therapy

    SciTech Connect

    Sorriaux, J; Paganetti, H; Testa, M; Giantsoudi, D; Schuemann, J; Bertrand, D; Orban de Xivry, J.; Lee, J; Palmans, H; Vynckier, S; Sterpin, E

    2014-06-01

    Purpose: In current practice, most proton therapy centers apply IAEA TRS-398 reference dosimetry protocol. Quality correction factors (kQ) take into account in the dose determination process the differences in beam qualities used for calibration unit and for treatment unit. These quality correction factors are valid for specific reference conditions. TRS-398 reference conditions should be achievable in both scattered proton beams (i.e. DS) and scanned proton beams (i.e. PBS). However, it is not a priori clear if TRS-398 kQ data, which are based on Monte Carlo (MC) calculations in scattered beams, can be used for scanned beams. Using TOPAS-Geant4 MC simulations, the study aims to determine whether broad beam quality correction factors calculated in TRS-398 can be directly applied to PBS delivery modality. Methods: As reference conditions, we consider a 10×10×10 cm{sup 3} homogeneous dose distribution delivered by PBS system in a water phantom (32/10 cm range/modulation) and an air cavity placed at the center of the spread-out-Bragg-peak. In order to isolate beam differences, a hypothetical broad beam is simulated. This hypothetical beam reproduces exactly the same range modulation, and uses the same energy layers than the PBS field. Ion chamber responses are computed for the PBS and hypothetical beams and then compared. Results: For an air cavity of 2×2×0.2 cm{sup 3}, the ratio of ion chamber responses for the PBS and hypothetical beam qualities is 0.9991 ± 0.0016. Conclusion: Quality correction factors are insensitive to the delivery pattern of the beam (broad beam or PBS), as long as similar dose distributions are achieved. This investigation, for an air cavity, suggests that broad beam quality correction factors published in TRS-398 can be applied for scanned beams. J. Sorriaux is financially supported by a public-private partnership involving the company Ion Beam Applications (IBA)

  2. [Measurement of peak correction factor of Farmer chamber for calibration of flattening filter free (FFF) clinical photon beams].

    PubMed

    Kontra, Gábor; Major, Tibor; Polgár, Csaba

    2015-06-01

    Farmer-type ionization chambers are considered the most reliable detectors and for this reason they are most frequently used for the calibration of photon beams of medical linear accelerators. Flattening filter free (FFF) photon beams of linear accelerators have recently started to be used in radiotherapy. The dose profile of FFF beams is peaked in the center of the field and the dose distribution will be inhomogeneous along the axis of the 2.3 cm long measuring volume of the Farmer chamber. The peaked radiation field will result in volume averaging effects in the large Farmer chamber, therefore this chamber will underestimate the true central axis dose. Our objective was to determine the value of the peak correction factor (Kp) of Farmer-type chamber with measurements to avoid the underestimation of the central axis dose during the calibration of FFF radiation fields. Measurements were made with 6 MV and 10 MV flattened (6X and 10X) and FFF beams (6XFFF and 10XFFF) of a Varian TrueBeam medical linear accelerator in a solid water phantom at 10 cm depth. The source surface distance (SSD) was 100 cm, the field size was 10×10 cm and the dose rate was always 400 MU/min during the measurements. We delivered 100 MU in each measurement and the absorbed dose to water was calculated according to the IAEA TRS-398 dosimetry protocol. The measured signals of the ionization chambers were always corrected for the ion recombination loss. The ion recombination correction factors (Kr) were determined with the two-voltage method separately for the used ion chambers and for flattened and unflattened beams. First, we measured the dose to water with PTW TM30012 Farmer chamber in 6XFFF and 6X beams, then calculated the ratio of doses of 6XFFF and 6X beams (R6,Farmer). Immediately after this we repeated the above measurements with PTW TM31010 Semiflex chamber and determined the ratio of doses of 6XFFF and 6X beams again (R6,Semiflex). The length of the sensitive volume of the Semiflex

  3. [Measurement of peak correction factor of Farmer chamber for calibration of flattening filter free (FFF) clinical photon beams].

    PubMed

    Kontra, Gábor; Major, Tibor; Polgár, Csaba

    2015-06-01

    Farmer-type ionization chambers are considered the most reliable detectors and for this reason they are most frequently used for the calibration of photon beams of medical linear accelerators. Flattening filter free (FFF) photon beams of linear accelerators have recently started to be used in radiotherapy. The dose profile of FFF beams is peaked in the center of the field and the dose distribution will be inhomogeneous along the axis of the 2.3 cm long measuring volume of the Farmer chamber. The peaked radiation field will result in volume averaging effects in the large Farmer chamber, therefore this chamber will underestimate the true central axis dose. Our objective was to determine the value of the peak correction factor (Kp) of Farmer-type chamber with measurements to avoid the underestimation of the central axis dose during the calibration of FFF radiation fields. Measurements were made with 6 MV and 10 MV flattened (6X and 10X) and FFF beams (6XFFF and 10XFFF) of a Varian TrueBeam medical linear accelerator in a solid water phantom at 10 cm depth. The source surface distance (SSD) was 100 cm, the field size was 10×10 cm and the dose rate was always 400 MU/min during the measurements. We delivered 100 MU in each measurement and the absorbed dose to water was calculated according to the IAEA TRS-398 dosimetry protocol. The measured signals of the ionization chambers were always corrected for the ion recombination loss. The ion recombination correction factors (Kr) were determined with the two-voltage method separately for the used ion chambers and for flattened and unflattened beams. First, we measured the dose to water with PTW TM30012 Farmer chamber in 6XFFF and 6X beams, then calculated the ratio of doses of 6XFFF and 6X beams (R6,Farmer). Immediately after this we repeated the above measurements with PTW TM31010 Semiflex chamber and determined the ratio of doses of 6XFFF and 6X beams again (R6,Semiflex). The length of the sensitive volume of the Semiflex

  4. On the importance of high-frequency air-temperature fluctuations for spectroscopic corrections of open-path carbon dioxide flux measurements

    NASA Astrophysics Data System (ADS)

    Bogoev, Ivan; Helbig, Manuel; Sonnentag, Oliver

    2015-04-01

    A growing number of studies report systematic differences in CO2 flux estimates obtained with the two main types of gas analyzers: compared to eddy-covariance systems based on closed-path (CP) gas analyzers, systems with open-path (OP) gas analyzers systematically overestimate CO2 uptake during daytime periods with high positive sensible heat fluxes, while patterns for differences in nighttime CO2 exchange are less obvious. These biases have been shown to correlate with the sign and the magnitude of the sensible heat flux and to introduce large uncertainties when calculating annual CO2 budgets. In general, CP and OP gas analyzers commonly used to measure the CO2 density in the atmosphere operate on the principle of infrared light absorption approximated by Beer-Lambert's law. Non-dispersive interference-based optical filter elements are used to select spectral bands with strong attenuation of light transmission, characteristic to the gas of interest. The intensity of the light passing through the optical sensing path depends primarily on the amount of absorber gas in the measurement volume. Besides the density of the gas, barometric pressure and air temperature are additional factors affecting the strength and the half-width of the absorption lines. These so-called spectroscopic effects are accounted for by measuring barometric pressure and air temperature in the sensing path and scaling the light-intensity measurements before applying the calibration equation. This approach works well for CP gas analyzers with an intake tube that acts as a low-pass filter on fast air-temperature fluctuations. Low-frequency response temperature sensors in the measurement cell are therefore sufficient to account for spectroscopic temperature effects. In contrast, OP gas analyzers are exposed to high-frequency air-temperature fluctuations associated with the atmospheric surface-layer turbulent heat exchange. If not corrected adequately, these fast air-temperature variations can cause

  5. A new method for both harmonic voltage and harmonic current suppression and power factor correction in industrial power systems

    SciTech Connect

    Cheng, H.; Sasaki, Hiroshi; Yorino, Naoto

    1995-12-31

    This paper proposes a new method for designing a group of single tuned filters for both harmonic current injection suppression and harmonic voltage distortion reduction and power factor correction. The proposed method is based on three purposes: (1) reduction of harmonic voltage distortion in the source terminals to an acceptable level, (2) suppression of harmonic current injection in the source terminals to an acceptable level, (3) improvement of power factor at the source terminals. To determine the size of the capacitor in a group of single tuned filters, three new NLP mathematical formulations will be introduced. The first is to suppress harmonic current injection within an acceptable level. The second is to minimize the fundamental reactive power output while reducing harmonic voltage distortion to an acceptable level. The third is to determine an optimal assignment of reactive power output based on the results of harmonic voltage reduction and power factor correction. This new method has been demonstrated for designing a group of single tuned filters and its validity has been successfully confirmed through numerical simulation in a 35 KV industrial power system. The proposed method can efficiently provide an optimal coordination in a group of single tuned filters relating to suppressing harmonic current injection, reducing harmonic voltage distortion and improving power factor.

  6. [Impact of psychological factors on development and course of coronary artery disease [corrected]: should negative psychological factors be altered?].

    PubMed

    Vural, Mutlu; Başar, Emrullah

    2006-03-01

    Psychological factors effect the development and course of coronary heart disease (CHD). Hypothalamic-pituitary-adrenal dysregulation, reduced heart rate variability, diminished baroreflex sensitivity, impaired immune function and altered platelet function are proposed as significant psychophysiologic mechanisms to explain this association. Because psychological factors may influence several different stages of long atherosclerosis period, interventional studies aiming to alter negative psychological factors by behavioral and medical ways, expecting to prevent or improve CHD, have been discussed. Complementary to the traditional treatment, this new treatment strategy could be a different perspective and a nice promise for CHD patients.

  7. Novel, cyclic heat dissipation method for the correction of natural temperature gradients in sap flow measurements. Part 2. Laboratory validation.

    PubMed

    Reyes-Acosta, J Leonardo; Vandegehuchte, Maurits W; Steppe, Kathy; Lubczynski, Maciek W

    2012-07-01

    Sap flow measurements conducted with thermal dissipation probes (TDPs) are vulnerable to natural temperature gradient (NTG) bias. Few studies, however, attempted to explain the dynamics underlying the NTG formation and its influence on the sensors' signal. This study focused on understanding how the TDP signals are affected by negative and positive temperature influences from NTG and tested the novel cyclic heat dissipation (CHD) method to filter out the NTG bias. A series of three experiments were performed in which gravity-driven water flow was enforced on freshly cut stem segments of Fagus sylvatica L., while an artificial temperature gradient (ATG) was induced. The first experiment sought to confirm the incidence of the ATG on sensors. The second experiment established the mis-estimations caused by the biasing effect of the ATG on standard TDP measurements. The third experiment tested the accuracy of the CHD method to account for the ATG biasing effect, as compared with other cyclic correction methods. During experiments, sap flow measured by TDP was assessed against gravimetric measurements. The results show that negative and positive ATGs were comparable in pattern but substantially larger than field NTGs. Second, the ATG bias caused an overestimation of the standard TDP sap flux density of ∼17 cm(3) cm(-2) h(-1) by 76%, and the sap flux density of ∼2 cm(3) cm(-2) h(-1) by over 800%. Finally, the proposed CHD method successfully reduced the max. ATG bias to 25% at ∼11 cm(3) cm(-2) h(-1) and to 40% at ∼1 cm(3) cm(-2) h(-1). We concluded that: (i) the TDP method is susceptible to NTG especially at low flows; (ii) the CHD method successfully corrected the TDP signal and resulted in generally more accurate sap flux density estimates (mean absolute percentage error ranging between 11 and 21%) than standard constant power TDP method and other cyclic power methods; and (iii) the ATG enforcing system is a suitable way of re-creating NTG for future tests. PMID

  8. Correction of measured Gamma-Knife output factors for angular dependence of diode detectors and PinPoint ionization chamber.

    PubMed

    Hršak, Hrvoje; Majer, Marija; Grego, Timor; Bibić, Juraj; Heinrich, Zdravko

    2014-12-01

    Dosimetry for Gamma-Knife requires detectors with high spatial resolution and minimal angular dependence of response. Angular dependence and end effect time for p-type silicon detectors (PTW Diode P and Diode E) and PTW PinPoint ionization chamber were measured with Gamma-Knife beams. Weighted angular dependence correction factors were calculated for each detector. The Gamma-Knife output factors were corrected for angular dependence and end effect time. For Gamma-Knife beams angle range of 84°-54°. Diode P shows considerable angular dependence of 9% and 8% for the 18 mm and 14, 8, 4 mm collimator, respectively. For Diode E this dependence is about 4% for all collimators. PinPoint ionization chamber shows angular dependence of less than 3% for 18, 14 and 8 mm helmet and 10% for 4 mm collimator due to volumetric averaging effect in a small photon beam. Corrected output factors for 14 mm helmet are in very good agreement (within ±0.3%) with published data and values recommended by vendor (Elekta AB, Stockholm, Sweden). For the 8 mm collimator diodes are still in good agreement with recommended values (within ±0.6%), while PinPoint gives 3% less value. For the 4 mm helmet Diodes P and E show over-response of 2.8% and 1.8%, respectively. For PinPoint chamber output factor of 4 mm collimator is 25% lower than Elekta value which is generally not consequence of angular dependence, but of volumetric averaging effect and lack of lateral electronic equilibrium. Diodes P and E represent good choice for Gamma-Knife dosimetry.

  9. Bias correction of reanalysis data for assessment of climate change effects on river systems in a data scarce area : a case study for precipitation and temperature

    NASA Astrophysics Data System (ADS)

    Maruya, Y.; Hipsey, M. R.; Watanabe, S.; Adiyanti, S.; Tachikawa, Y.

    2015-12-01

    Outputs from Global Climate Models (GCM) are increasingly used to assess the impacts of climate change on water resources, however it is often necessary to correct biases in GCM predictions relative to available observations. Bias correction should be based on over 20 years of observational data in order to reproduce long-term trends (e.g. yearly and monthly trend and less frequent extreme events). In previous studies, reanalysis data has been used instead of observation data when bias correction method is applied for outputs from GCM in the world and a data scarce area like observation data is under 20 years. Reanalysis data has biases between the observation data in local scale since it has been reproduced for global scale. However, bias correction method for reanalysis data has not been clarified for local scale. Therefore, this study aims to develop the bias correction method for re-analysis data based on observation data. Our application compared 6 hourly precipitation and monthly temperature data from an Australian site with the ERA-Interim (ERA) provided by ECMRWF reanalysis data. Initially, patterns in the 6 hourly precipitation data from the ERA were poorly predicted (r = 0.34), however, monthly precipitation and temperature were in good agreement (r: 0.79 and 0.996, respectively). Moreover, monthly precipitation events, average precipitation and standard deviation of precipitation in observation are associated with monthly precipitation in ERA (CC: 0.7011, 0.8168 and 0.7523, respectively). Therefore, we applied a bias correction method to correct the bias within ERA. Firstly, we corrected monthly precipitation and temperature and estimated monthly precipitation events, average and standard deviation of precipitation based on relationship observation and reanalysis data. Then, we corrected average and standard deviation of precipitation using them that was estimated. Finally, we corrected precipitation applying cdf method to reproduce low frequency large

  10. Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions.

    PubMed

    Nefiodov, A V; Plunien, G; Soff, G

    2002-08-19

    The influence of nuclear polarization on the bound-electron g factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron g factor in highly charged ions.

  11. Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions.

    PubMed

    Nefiodov, A V; Plunien, G; Soff, G

    2002-08-19

    The influence of nuclear polarization on the bound-electron g factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron g factor in highly charged ions. PMID:12190457

  12. Metabolic Correction of Congenital Erythropoietic Porphyria with iPSCs Free of Reprogramming Factors

    PubMed Central

    Bedel, Aurélie; Taillepierre, Miguel; Guyonnet-Duperat, Véronique; Lippert, Eric; Dubus, Pierre; Dabernat, Sandrine; Mautuit, Thibaud; Cardinaud, Bruno; Pain, Catherine; Rousseau, Benoît; Lalanne, Magalie; Ged, Cécile; Duchartre, Yann; Richard, Emmanuel; de Verneuil, Hubert; Moreau-Gaudry, François

    2012-01-01

    Congenital erythropoietic porphyria (CEP) is due to a deficiency in the enzymatic activity of uroporphyrinogen III synthase (UROS); such a deficiency leads to porphyrin accumulation and results in skin lesions and hemolytic anemia. CEP is a candidate for retrolentivirus-mediated gene therapy, but recent reports of insertional leukemogenesis underscore the need for safer methods. The discovery of induced pluripotent stem cells (iPSCs) has opened up new horizons in gene therapy because it might overcome the difficulty of obtaining sufficient amounts of autologous hematopoietic stem cells for transplantation and the risk of genotoxicity. In this study, we isolated keratinocytes from a CEP-affected individual and generated iPSCs with two excisable lentiviral vectors. Gene correction of CEP-derived iPSCs was obtained by lentiviral transduction of a therapeutic vector containing UROS cDNA under the control of an erythroid-specific promoter shielded by insulators. One iPSC clone, free of reprogramming genes, was obtained with a single proviral integration of the therapeutic vector in a genomic safe region. Metabolic correction of erythroblasts derived from iPSC clones was demonstrated by the disappearance of fluorocytes. This study reports the feasibility of porphyria gene therapy with the use of iPSCs. PMID:22795135

  13. A feedforward compensation design in critical conduction mode boost power factor correction for low-power low totalharmonic distortion

    NASA Astrophysics Data System (ADS)

    Yani, Li; Yintang, Yang; Zhangming, Zhu; Wei, Qiang

    2012-03-01

    For low-power low total harmonic distortion (THD), based on the CSMC 0.5 μm BCD process, a novel boost power factor correction (PFC) converter in critical conduction mode is discussed and analyzed. Feedforward compensation design is introduced in order to increase the PWM duty cycle and supply more conversion energy near the input voltage zero-crossing points, thus regulating the inductor current of the PFC converter and compensating the system loop gain change with ac line voltage. Both theoretical and practical results reveal that the proposed PFC converter with feedforward compensation cell has better power factor and THD performance, and is suitable for low-power low THD design applications. The experimental THD of the boost PFC converter is 4.5%, the start-up current is 54 μA, the stable operating current is 3.85 mA, the power factor is 0.998 and the efficiency is 95.2%.

  14. Correction Factor for Gaussian Deconvolution of Optically Thick Linewidths in Homogeneous Sources

    NASA Technical Reports Server (NTRS)

    Kastner, S. O.; Bhatia, A. K.

    1999-01-01

    Profiles of optically thick, non-Gaussian emission line profiles convoluted with Gaussian instrumental profiles are constructed, and are deconvoluted on the usual Gaussian basis to examine the departure from accuracy thereby caused in "measured" linewidths. It is found that "measured" linewidths underestimate the true linewidths of optically thick lines, by a factor which depends on the resolution factor r congruent to Doppler width/instrumental width and on the optical thickness tau(sub 0). An approximating expression is obtained for this factor, applicable in the range of at least 0 <= tau(sub 0) <= 10, which can provide estimates of the true linewidth and optical thickness.

  15. A transient, Hex-Z nodal code corrected by discontinuity factors. Volume 1: The transient nodal code; Final report

    SciTech Connect

    Shatilla, Y.A.M.; Henry, A.F.

    1993-12-31

    This document constitutes Volume 1 of the Final Report of a three-year study supported by the special Research Grant Program for Nuclear Energy Research set up by the US Department of Energy. The original motivation for the work was to provide a fast and accurate computer program for the analysis of transients in heavy water or graphite-moderated reactors being considered as candidates for the New Production Reactor. Thus, part of the funding was by way of pass-through money from the Savannah River Laboratory. With this intent in mind, a three-dimensional (Hex-Z), general-energy-group transient, nodal code was created, programmed, and tested. In order to improve accuracy, correction terms, called {open_quotes}discontinuity factors,{close_quotes} were incorporated into the nodal equations. Ideal values of these factors force the nodal equations to provide node-integrated reaction rates and leakage rates across nodal surfaces that match exactly those edited from a more exact reference calculation. Since the exact reference solution is needed to compute the ideal discontinuity factors, the fact that they result in exact nodal equations would be of little practical interest were it not that approximate discontinuity factors, found at a greatly reduced cost, often yield very accurate results. For example, for light-water reactors, discontinuity factors found from two-dimensional, fine-mesh, multigroup transport solutions for two-dimensional cuts of a fuel assembly provide very accurate predictions of three-dimensional, full-core power distributions. The present document (volume 1) deals primarily with the specification, programming and testing of the three-dimensional, Hex-Z computer program. The program solves both the static (eigenvalue) and transient, general-energy-group, nodal equations corrected by user-supplied discontinuity factors.

  16. Spectral dependence on the correction factor of erythemal UV for cloud, aerosol, total ozone, and surface properties: A modeling study

    NASA Astrophysics Data System (ADS)

    Park, Sang Seo; Jung, Yeonjin; Lee, Yun Gon

    2016-07-01

    Radiative transfer model simulations were used to investigate the erythemal ultraviolet (EUV) correction factors by separating the UV-A and UV-B spectral ranges. The correction factor was defined as the ratio of EUV caused by changing the amounts and characteristics of the extinction and scattering materials. The EUV correction factors (CFEUV) for UV-A [CFEUV(A)] and UV-B [CFEUV(B)] were affected by changes in the total ozone, optical depths of aerosol and cloud, and the solar zenith angle. The differences between CFEUV(A) and CFEUV(B) were also estimated as a function of solar zenith angle, the optical depths of aerosol and cloud, and total ozone. The differences between CFEUV(A) and CFEUV(B) ranged from -5.0% to 25.0% for aerosols, and from -9.5% to 2.0% for clouds in all simulations for different solar zenith angles and optical depths of aerosol and cloud. The rate of decline of CFEUV per unit optical depth between UV-A and UV-B differed by up to 20% for the same aerosol and cloud conditions. For total ozone, the variation in CFEUV(A) was negligible compared with that in CFEUV(B) because of the effective spectral range of the ozone absorption band. In addition, the sensitivity of the CFEUVs due to changes in surface conditions (i.e., surface albedo and surface altitude) was also estimated by using the model in this study. For changes in surface albedo, the sensitivity of the CFEUVs was 2.9%-4.1% per 0.1 albedo change, depending on the amount of aerosols or clouds. For changes in surface altitude, the sensitivity of CFEUV(B) was twice that of CFEUV(A), because the Rayleigh optical depth increased significantly at shorter wavelengths.

  17. Accurately evaluating Young's modulus of polymers through nanoindentations: A phenomenological correction factor to the Oliver and Pharr procedure

    NASA Astrophysics Data System (ADS)

    Tranchida, Davide; Piccarolo, Stefano; Loos, Joachim; Alexeev, Alexander

    2006-10-01

    The Oliver and Pharr [J. Mater. Res. 7, 1564 (1992)] procedure is a widely used tool to analyze nanoindentation force curves obtained on metals or ceramics. Its application to polymers is, however, difficult, as Young's moduli are commonly overestimated mainly because of viscoelastic effects and pileup. However, polymers spanning a large range of morphologies have been used in this work to introduce a phenomenological correction factor. It depends on indenter geometry: sets of calibration indentations have to be performed on some polymers with known elastic moduli to characterize each indenter.

  18. In Vivo Gene Therapy of Hemophilia B: Sustained Partial Correction in Factor IX-Deficient Dogs

    NASA Astrophysics Data System (ADS)

    Kay, Mark A.; Rothenberg, Steven; Landen, Charles N.; Bellinger, Dwight A.; Leland, Frances; Toman, Carol; Finegold, Milton; Thompson, Arthur R.; Read, M. S.; Brinkhous, Kenneth M.; Woo, Savio L. C.

    1993-10-01

    The liver represents a model organ for gene therapy. A method has been developed for hepatic gene transfer in vivo by the direct infusion of recombinant retroviral vectors into the portal vasculature, which results in the persistent expression of exogenous genes. To determine if these technologies are applicable for the treatment of hemophilia B patients, preclinical efficacy studies were done in a hemophilia B dog model. When the canine factor IX complementary DNA was transduced directly into the hepatocytes of affected dogs in vivo, the animals constitutively expressed low levels of canine factor IX for more than 5 months. Persistent expression of the clotting. factor resulted in reductions of whole blood clotting and partial thromboplastin times of the treated animals. Thus, long-term treatment of hemophilia B patients may be feasible by direct hepatic gene therapy in vivo.

  19. Determination of the quenching correction factors for plastic scintillation detectors in therapeutic high-energy proton beams

    PubMed Central

    Wang, L L W; Perles, L A; Archambault, L; Sahoo, N; Mirkovic, D; Beddar, S

    2013-01-01

    The plastic scintillation detectors (PSD) have many advantages over other detectors in small field dosimetry due to its high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs will undergo a quenching effect which makes the signal level reduced significantly when the detector is close to Bragg peak where the linear energy transfer (LET) for protons is very high. This study measures the quenching correction factor (QCF) for a PSD in clinical passive-scattering proton beams and investigates the feasibility of using PSDs in depth-dose measurements in proton beams. A polystyrene based PSD (BCF-12, ϕ0.5mm×4mm) was used to measure the depth-dose curves in a water phantom for monoenergetic unmodulated proton beams of nominal energies 100, 180 and 250 MeV. A Markus plane-parallel ion chamber was also used to get the dose distributions for the same proton beams. From these results, the QCF as a function of depth was derived for these proton beams. Next, the LET depth distributions for these proton beams were calculated by using the MCNPX Monte Carlo code, based on the experimentally validated nozzle models for these passive-scattering proton beams. Then the relationship between the QCF and the proton LET could be derived as an empirical formula. Finally, the obtained empirical formula was applied to the PSD measurements to get the corrected depth-dose curves and they were compared to the ion chamber measurements. A linear relationship between QCF and LET, i.e. Birks' formula, was obtained for the proton beams studied. The result is in agreement with the literature. The PSD measurements after the quenching corrections agree with ion chamber measurements within 5%. PSDs are good dosimeters for proton beam measurement if the quenching effect is corrected appropriately. PMID:23128412

  20. Predictive factors for perioperative blood transfusion in surgeries for correction of idiopathic, neuromuscular or congenital scoliosis

    PubMed Central

    Cristante, Alexandre Fogaça; Borges, Paulo Alvim; Barbosa, Angelo Roberto; Letaif, Olavo Biraghi; Marcon, Raphael Martus; de Barros-Filho, Tarcisio Eloy Pessoa

    2014-01-01

    OBJECTIVE: To evaluate the association of clinical and demographic variables in patients requiring blood transfusion during elective surgery to treat scoliosis with the aim of identifying markers predictive of the need for blood transfusion. METHODS: Based on the review of medical charts at a public university hospital, this retrospective study evaluated whether the following variables were associated with the need for red blood cell transfusion (measured by the number of packs used) during scoliosis surgery: scoliotic angle, extent of arthrodesis (number of fused levels), sex of the patient, surgery duration and type of scoliosis (neuromuscular, congenital or idiopathic). RESULTS: Of the 94 patients evaluated in a 55-month period, none required a massive blood transfusion (most patients needed less than two red blood cell packs). The number of packs was not significantly associated with sex or type of scoliosis. The extent of arthrodesis (r = 0.103), surgery duration (r = 0.144) and scoliotic angle (r = 0.004) were weakly correlated with the need for blood transfusion. Linear regression analysis showed an association between the number of spine levels submitted to arthrodesis and the volume of blood used in transfusions (p = 0.001). CONCLUSION: This study did not reveal any evidence of a significant association between the need for red blood cell transfusion and scoliotic angle, sex or surgery duration in scoliosis correction surgery. Submission of more spinal levels to arthrodesis was associated with the use of a greater number of blood packs. PMID:25518018

  1. Assessment of ionization chamber correction factors in photon beams using a time saving strategy with PENELOPE code.

    PubMed

    Reis, C Q M; Nicolucci, P

    2016-02-01

    The purpose of this study was to investigate Monte Carlo-based perturbation and beam quality correction factors for ionization chambers in photon beams using a saving time strategy with PENELOPE code. Simulations for calculating absorbed doses to water using full spectra of photon beams impinging the whole water phantom and those using a phase-space file previously stored around the point of interest were performed and compared. The widely used NE2571 ionization chamber was modeled with PENELOPE using data from the literature in order to calculate absorbed doses to the air cavity of the chamber. Absorbed doses to water at reference depth were also calculated for providing the perturbation and beam quality correction factors for that chamber in high energy photon beams. Results obtained in this study show that simulations with phase-space files appropriately stored can be up to ten times shorter than using a full spectrum of photon beams in the input-file. Values of kQ and its components for the NE2571 ionization chamber showed good agreement with published values in the literature and are provided with typical statistical uncertainties of 0.2%. Comparisons to kQ values published in current dosimetry protocols such as the AAPM TG-51 and IAEA TRS-398 showed maximum percentage differences of 0.1% and 0.6% respectively. The proposed strategy presented a significant efficiency gain and can be applied for a variety of ionization chambers and clinical photon beams.

  2. Correction of the equilibrium temperature caused by slight evaporation of water in protein crystal growth cells during long-term space experiments at International Space Station

    NASA Astrophysics Data System (ADS)

    Fujiwara, Takahisa; Suzuki, Yoshihisa; Yoshizaki, Izumi; Tsukamoto, Katsuo; Murayama, Kenta; Fukuyama, Seijiro; Hosokawa, Kouhei; Oshi, Kentaro; Ito, Daisuke; Yamazaki, Tomoya; Tachibana, Masaru; Miura, Hitoshi

    2015-08-01

    The normal growth rates of the {110} faces of tetragonal hen egg-white lysozyme crystals, R, were measured as a function of the supersaturation σ parameter using a reflection type interferometer under μG at the International Space Station (NanoStep Project). Since water slightly evaporated from in situ observation cells during a long-term space station experiment for several months, equilibrium temperature Te changed, and the actual σ, however, significantly increased mainly due to the increase in salt concentration Cs. To correct σ, the actual Cs and protein concentration Cp, which correctly represent the measured Te value in space, were first calculated. Second, a new solubility curve with the corrected Cs was plotted. Finally, the revised σ was obtained from the new solubility curve. This correction method successfully revealed that the 2.8% water was evaporated from the solution, leading to 2.8% increase in the Cs and Cp of the solution.

  3. Monte Carlo-based correction factors for ion chamber dosimetry in heterogeneous phantoms for megavoltage photon beams.

    PubMed

    Araki, Fujio

    2012-11-21

    The purpose of this study was to investigate the perturbation correction factors and inhomogeneity correction factors (ICFs) for a thin-walled cylindrical ion chamber in a heterogeneous phantom including solid water, lung and bone plastic materials. The perturbation factors due to the replacement of the air cavity, non-water equivalence of the wall and the stem, non-air equivalence of the central electrode and the overall perturbation factor, P(Q), for a cylindrical chamber, in the heterogeneous phantom were calculated with the EGSnrc/Cavity Monte Carlo code for 6 and 15 MV photon beams. The PTW31010 (0.125 cm(3)) chamber was modeled with Monte Carlo simulations, and was used for measurements and calculations of percentage depth ionization (PDI) or percentage depth dose (PDD). ICFs were calculated from the ratio of the product of the stopping power ratios (SPRs) and P(Q) of lung or bone to solid water. Finally, the measured PDIs were converted to PDDs by using ICFs and were compared with those calculated by the Monte Carlo method. The perturbation effect for the ion chamber in lung material is insignificant at 5 × 5 and 10 × 10 cm(2) fields, but the effect needs to be considered under conditions of lateral electron disequilibrium with a 3 × 3 cm(2) field. ICFs in lung varied up to 2% and 4% depending on the field size for 6 and 15 MV, respectively. For bone material, the perturbation effects due to the chamber wall and the stem were more significant at up to 3.5% and 1.6% for 6 MV, respectively. ICFs for bone material were approximately 0.945 and 0.940 for 6 and 15 MV, respectively. The converted PDDs by using ICFs were in good agreement with Monte Carlo calculated PDDs. The chamber perturbation correction and SPRs should strictly be considered for ion chamber dosimetry in heterogeneous media. This is more important for small field dosimetry in lung and bone materials. PMID:23103477

  4. Quantitative measurement of temperature by proton resonance frequency shift at low field: a general method to correct non-linear spatial and temporal phase deformations

    NASA Astrophysics Data System (ADS)

    Grimault, S.; Lucas, T.; Quellec, S.; Mariette, F.

    2004-09-01

    MRI thermometry methods are usually based on the temperature dependence of the proton resonance frequency. Unfortunately, these methods are very sensitive to the phase drift induced by the instability of the scanner which prevents any temperature mapping over long periods of time. A general method based on 3D spatial modelling of the phase drift as a function of time is presented. The MRI temperature measurements were validated on gel samples with uniform and constant temperature and with a linear temperature gradient. In the case of uniform temperature conditions, correction of the phase drift proved to be essential when long periods of acquisition were required, as bias could reach values of up to 200 °C in its absence. The temperature uncertainty measured by MRI was 1.2 °C in average over 290 min. This accuracy is coherent with the requirements for food applications especially when thermocouples are useless.

  5. Temperature Data Assimilation with Salinity Corrections: Validation for the NSIPP Ocean Data Assimilation System in the Tropical Pacific Ocean, 1993-1998

    NASA Technical Reports Server (NTRS)

    Troccoli, Alberto; Rienecker, Michele M.; Keppenne, Christian L.; Johnson, Gregory C.

    2003-01-01

    The NASA Seasonal-to-Interannual Prediction Project (NSIPP) has developed an Ocean data assimilation system to initialize the quasi-isopycnal ocean model used in our experimental coupled-model forecast system. Initial tests of the system have focused on the assimilation of temperature profiles in an optimal interpolation framework. It is now recognized that correction of temperature only often introduces spurious water masses. The resulting density distribution can be statically unstable and also have a detrimental impact on the velocity distribution. Several simple schemes have been developed to try to correct these deficiencies. Here the salinity field is corrected by using a scheme which assumes that the temperature-salinity relationship of the model background is preserved during the assimilation. The scheme was first introduced for a zlevel model by Troccoli and Haines (1999). A large set of subsurface observations of salinity and temperature is used to cross-validate two data assimilation experiments run for the 6-year period 1993-1998. In these two experiments only subsurface temperature observations are used, but in one case the salinity field is also updated whenever temperature observations are available.

  6. Single-Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

    SciTech Connect

    Chinthavali, Madhu Sudhan; Onar, Omer C; Miller, John M; Tang, Lixin

    2013-01-01

    Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance. To understand the power flow through the system this paper presents a novel approach to the system model and the impact of different control parameters on the load power. The implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation is also discussed.

  7. Perinatal factors associated with neural tube defects (anencephaly [correction of anancephaly], spina bifida and encephalocele).

    PubMed

    Ogata, A J; Camano, L; Brunoni, D

    1992-01-01

    The objective of the present study was to determine the presence of risk factors for the occurrence of neural tube defects. Data for 33,535 births which occurred at Hospital do Servidor Público Estadual de São Paulo from July 1973 to December 1986 were collected in a prospective manner as recommended by "Estudo Colaborativo Latino-Americano de Malformações Congênitas" (ECLAMC, Collaborative Latin American Study on Congenital Malformations). Twenty-six cases of neural tube defects were detected (0.77/1000 births). Of these, 11 were cases of spina bifida (0.39/1000 births), 9 of anencephaly (0.27/1000 births) and 6 of encephalocele (0.18/1000 births). We observed a higher frequency of polyhydramnios, premature labor, Apgar scores of less than 7 at the first and fifth minutes, low birth weight and intrauterine growth retardation.

  8. Factors affecting the adsorption of buchnericin LB, a bacteriocin produced by Lactobacillus [correction of Lactocobacillus] buchneri.

    PubMed

    Yildirim, Zeliha; Avşar, Yahya Kemal; Yildirim, Metin

    2002-01-01

    Buchnericin-LB adsorbs to gram-positive but not to gram-negative bacteria. The tested gram-positive bacteria were species of Lactobacillus, Pediococcus, Leuconostoc, Enterococcus, Lactococcus, Listeria, Bacillus, Staphylococcus; gram-negative bacteria belonged to the genera Salmonella, Escherichia, Yersinia and Pseudomonas. Buchnericin-LB adsorption depended on pH but not on time and temperature. Also some anions of salts and lipoteichoic acid reduced or inhibited its adsorption. Treatment of cells and cell walls of sensitive bacteria with detergents, organic solvents or enzymes did not affect subsequent binding of buchnericin-LB. Treatment with buchnericin-LB caused sensitive cells to lose high amounts of intracellular K+ ions and UV-absorbing materials and became more permeable to o-nitrophenol-beta-D-galactopyranoside. Buchnericin-LB (640-2560 AU/ml) decreased the colony forming units (99%) and absorbance values of Listeria monocytogenes and Bacillus cereus. These results indicate that the mode of action of buchnericin-LB is bactericidal and its lethal effect is very rapid.

  9. Temperature-stable and high Q-factor TiO2 Bragg reflector resonator

    NASA Astrophysics Data System (ADS)

    Breeze, Jonathan; Krupka, Jerzy; Centeno, Anthony; Alford, Neil McN

    2009-02-01

    The highest Q-factor resonators employ whispering gallery modes in single-crystal sapphire but have poor temperature stability. Rutile was the first dielectric material used to construct a microwave dielectric resonator. However, its very high temperature coefficient of permittivity made it unsuitable for practical applications. This paper reports a high Q-factor (50 000) and temperature-stable spherical Bragg reflector resonator based on polycrystalline rutile operating at 29.9 GHz. Temperature stability is achieved by adjusting the electric filling factor of a spherical shell so that in combination with its highly negative temperature coefficient of permittivity, the effect of thermal expansion is exactly cancelled out.

  10. Factor VIII delivered by hematopoietic stem cell-derived B cells corrects the phenotype of hemophilia A mice

    PubMed Central

    Ramezani, Ali; Zweier-Renn, Lynnsey A.; Hawley, Robert G.

    2011-01-01

    Summary The main impediments to clinical application of hematopoietic stem cell (HSC) gene therapy for treatment of hemophilia A are the bone marrow transplant-related risks and the potential for insertional mutagenesis caused by retroviral vectors. To circumvent these limitations, we have adapted a nonmyeloablative conditioning regimen and directed factor VIII (FVIII) protein synthesis to B lineage cells using an insulated lentiviral vector containing an immunoglobulin heavy chain enhancer-promoter. Transplantation of lentiviral vector-modified HSCs resulted in therapeutic levels of FVIII in the circulation of all transplanted mice for the duration of the study (6 months). Immunostaining of spleen cells showed that the majority of FVIII was synthesized by B220+ B cells and CD138+ plasma cells. Subsequent challenge with recombinant FVIII elicited at most a minor anti-FVIII antibody response, demonstrating induction of immune hyporesponsiveness. All transplant recipients exhibited clot formation and survived tail clipping, indicating correction of their hemophilic phenotype. Therapeutic levels of FVIII could be transferred to secondary recipients by bone marrow transplantation, confirming gene transfer into long-term repopulating HSCs. Moreover, short-term therapeutic FVIII levels could also be achieved in secondary recipients by adoptive transfer of HSC-derived splenic B cells. Our findings support pursuit of B cell-directed protein delivery as a potential clinical approach to treat hemophilia A and other disorders correctable by systemically distributed proteins. PMID:21264447

  11. Factors affecting rectal temperature measurement using commonly available digital thermometers.

    PubMed

    Naylor, Jonathan M; Streeter, Renee M; Torgerson, Paul

    2012-02-01

    Rectal temperature measurement is an essential part of physical examination of cattle and some physiological experiments. Modern digital thermometers are often used to measure rectal temperatures by students; this study describes their reliability and appropriate use. Students measured rectal temperature on 53 occasions using their personal digital thermometer and techniques gained from previous instruction, rectal temperature was also measured by an experienced person using a Cornell mercury thermometer completely inserted in the rectum. Cornell mercury thermometers values were 38.95±0.05°C (mean±1 SE, n=53). Student rectal temperature measurements using their initial technique were nearly 0.5°C lower, 38.46±0.07°C. After receiving instruction to insert the digital thermometer to the window, student obtained values were 38.77±0.06°C; these are significantly higher than with the student's initial technique and closer to those obtained with a Cornell thermometer. In a series of 53 water bath tests, student owned thermometers recorded similar mean values to those of a traceable (reference) digital thermometer, Cornell mercury thermometer readings were 0.2°C higher. 10 individual digital thermometers were repeatedly tested against a traceable thermometer in a water bath, one was inaccurate. In a separate experiment a trained clinician tested the effect of angle of insertion of a digital thermometer on temperature readings and the affect was <0.1°C. We conclude that accurate temperature measurements using digital thermometers are only likely if the thermometer is inserted to the beginning of the window and the thermometer's accuracy is checked periodically.

  12. Reliability Analysis of a Composite Wind Turbine Blade Section Using the Model Correction Factor Method: Numerical Study and Validation

    NASA Astrophysics Data System (ADS)

    Dimitrov, Nikolay; Friis-Hansen, Peter; Berggreen, Christian

    2013-02-01

    Reliability analysis of fiber-reinforced composite structures is a relatively unexplored field, and it is therefore expected that engineers and researchers trying to apply such an approach will meet certain challenges until more knowledge is accumulated. While doing the analyses included in the present paper, the authors have experienced some of the possible pitfalls on the way to complete a precise and robust reliability analysis for layered composites. Results showed that in order to obtain accurate reliability estimates it is necessary to account for the various failure modes described by the composite failure criteria. Each failure mode has been considered in a separate component reliability analysis, followed by a system analysis which gives the total probability of failure of the structure. The Model Correction Factor method used in connection with FORM (First-Order Reliability Method) proved to be a fast and efficient way to calculate the reliability index of a complex composite structure.

  13. Correction of Hypertension by Normalization of Endothelial Levels of Fibroblast Growth Factor and Nitric Oxide Synthase in Spontaneously Hypertensive Rats

    NASA Astrophysics Data System (ADS)

    Cuevas, Pedro; Garcia-Calvo, Margarita; Carceller, Fernando; Reimers, Diana; Zazo, Mercedes; Cuevas, Begona; Munoz-Willery, Isabel; Martinez-Coso, Victoria; Lamas, Santiago; Gimenez-Gallego, Guillermo

    1996-10-01

    Acidic and basic fibroblast growth factors (FGFs) share a wide range of diverse biological activities. To date, low levels of FGF have not been correlated with a pathophysiologic state. We report that blood vessels of spontaneously hypertensive rats are shown to be associated with a marked decrement in endothelial basic FGF content. This decrement correlates both with hypertension and with a decrease in the endothelial content of nitric oxide synthase. restoration of FGF to physiological levels in the vascular wall, either by systemic administration or by in vivo gene transfer, significantly augmented the number of endothelial cells with positive immunostaining for nitric oxide synthase, corrected hypertension, and ameliorated endothelial-dependent responses to vasoconstrictors. These results suggest an important role for FGFs in blood pressure homeostasis and open new avenues for the understanding of the etiology and treatment of hypertension.

  14. SU-F-BRE-01: A Rapid Method to Determine An Upper Limit On a Radiation Detector's Correction Factor During the QA of IMRT Plans

    SciTech Connect

    Kamio, Y; Bouchard, H

    2014-06-15

    Purpose: Discrepancies in the verification of the absorbed dose to water from an IMRT plan using a radiation dosimeter can be wither caused by 1) detector specific nonstandard field correction factors as described by the formalism of Alfonso et al. 2) inaccurate delivery of the DQA plan. The aim of this work is to develop a simple/fast method to determine an upper limit on the contribution of composite field correction factors to these discrepancies. Methods: Indices that characterize the non-flatness of the symmetrised collapsed delivery (VSC) of IMRT fields over detector-specific regions of interest were shown to be correlated with IMRT field correction factors. The indices introduced are the uniformity index (UI) and the mean fluctuation index (MF). Each one of these correlation plots have 10 000 fields generated with a stochastic model. A total of eight radiation detectors were investigated in the radial orientation. An upper bound on the correction factors was evaluated by fitting values of high correction factors for a given index value. Results: These fitted curves can be used to compare the performance of radiation dosimeters in composite IMRT fields. Highly water-equivalent dosimeters like the scintillating detector (Exradin W1) and a generic alanine detector have been found to have corrections under 1% over a broad range of field modulations (0 – 0.12 for MF and 0 – 0.5 for UI). Other detectors have been shown to have corrections of a few percent over this range. Finally, a full Monte Carlo simulations of 18 clinical and nonclinical IMRT field showed good agreement with the fitted curve for the A12 ionization chamber. Conclusion: This work proposes a rapid method to evaluate an upper bound on the contribution of correction factors to discrepancies found in the verification of DQA plans.

  15. Analysis of risk factors associated with hepatitis B and C infection in correctional institutions in British Columbia.

    PubMed

    Préfontaine, R; Chaudhary, R; Mathias, R

    1994-07-01

    The factors associated with infection with hepatitis B (hbv) and C viruses (hcv) were studied in residents of correctional institutions in British Columbia. Four hundred and fifteen residents volunteered to participate in this study. Among 415 residents tested, 28% were positive for hvb or hcv markers. Sixty-five per cent of the residents positive for hbv markers were also infected with hcv. However, in hbv-negative residents, only 14% were positive for antibody to hcv (anti-hcv). The highest rates for hbv and hcv were in 25- to 44-year-old residents. The analysis of risk factors and infection predictors in 354 residents showed that intravenous drug use and history of hepatitis were associated with infection with both hbv and hcv. The relative risk for hbv in intravenous drug users was 4.4 times that in nonusers; for hcv relative risk was 3.4 times. In the group with history of hepatitis, the relative risk was 6.2 and 4.5 times for hbv and hcv, respectively. The multivariate analysis of the data showed that both intravenous drug use and a history of hepatitis were significant (P<0.0001). Tattooing or history of transfusion was not associated with increased risk for hcv, but tattooing and age were significant factors for hbv. PMID:22346493

  16. Basic factors controlling pest in high temperature systems

    NASA Technical Reports Server (NTRS)

    Berkowitz-Mattuck, J.; Rossetti, M.

    1971-01-01

    The catastrophic disintegration in air at intermediate temperatures of refractory materials which are very resistant to oxidation at high temperatures is known as pest. A study was undertaken to determine whether the mechanism proposed for pest failure in silicides might also be responsible for pest failure in NbAl3. The aim was to correlate oxidation kinetics in the range where disintegration of NbAl3 is observed with delayed failure data obtained under similar conditions. Studies were also undertaken to develop some understanding of deformation mechanisms in both silicides and aluminides.

  17. Lattice constants of pure methane and carbon dioxide hydrates at low temperatures. Implementing quantum corrections to classical molecular dynamics studies

    NASA Astrophysics Data System (ADS)

    Costandy, Joseph; Michalis, Vasileios K.; Tsimpanogiannis, Ioannis N.; Stubos, Athanassios K.; Economou, Ioannis G.

    2016-03-01

    We introduce a simple correction to the calculation of the lattice constants of fully occupied structure sI methane or carbon dioxide pure hydrates that are obtained from classical molecular dynamics simulations using the TIP4PQ/2005 water force field. The obtained corrected lattice constants are subsequently used in order to obtain isobaric thermal expansion coefficients of the pure gas hydrates that exhibit a trend that is significantly closer to the experimental behavior than previously reported classical molecular dynamics studies.

  18. Factors Controlling Elevated Temperature Strength Degradation of Silicon Carbide Composites

    NASA Technical Reports Server (NTRS)

    2005-01-01

    For 5 years, the cooperative agreement NCC3-763 has focused on the development and understanding of Sic-based composites. Most of the work was performed in the area of SiC fiber-reinforced composites for UEET and NGLT and in collaboration with Goodrich Corporation under a partially reimbursable Space Act Agreement. A smaller amount of work was performed on C fiber-reinforced SiC matrix composites for NGLT. Major accomplishments during this agreement included: Improvements to the interphase used in melt-infiltrated (MI) SiC/SiC composites which increases the life under stressed-oxidation at intermediate temperatures referred to as "outside-debonding". This concept is currently in the patent process and received a Space Act Award. Mechanistic-based models of intermediate temperature degradation for MI SiC/SiC Quantification and relatively robust relationships for matrix crack evolution under stress in SiC/SiC composites which serve as the basis for stress-strain and elevated temperature life models The furthering of acoustic emission as a useful tool in composite damage evolution and the extension of the technique to other composite systems Development of hybrid C-SiC fiber-reinforced SiC matrix composites Numerous presentations at conferences, industry partners, and government centers and publications in recognized proceedings and journals. Other recognition of the author's accomplishments by NASA with a TGIR award (2004), NASA's Medal for Public Service (2004), and The American Ceramic Society s Richard M. Fulrath Award (2005). The following will briefly describe the work of the past five years in the three areas of interest: SiC/SiC composite development, mechanistic understanding and modeling of SiC/SiC composites, and environmental durability of C/SiC composites. More detail can be found in the publications cited at the end of this report.

  19. Lattice constants of pure methane and carbon dioxide hydrates at low temperatures. Implementing quantum corrections to classical molecular dynamics studies.

    PubMed

    Costandy, Joseph; Michalis, Vasileios K; Tsimpanogiannis, Ioannis N; Stubos, Athanassios K; Economou, Ioannis G

    2016-03-28

    We introduce a simple correction to the calculation of the lattice constants of fully occupied structure sI methane or carbon dioxide pure hydrates that are obtained from classical molecular dynamics simulations using the TIP4PQ/2005 water force field. The obtained corrected lattice constants are subsequently used in order to obtain isobaric thermal expansion coefficients of the pure gas hydrates that exhibit a trend that is significantly closer to the experimental behavior than previously reported classical molecular dynamics studies. PMID:27036466

  20. SU-E-T-101: Determination and Comparison of Correction Factors Obtained for TLDs in Small Field Lung Heterogenous Phantom Using Acuros XB and EGSnrc

    SciTech Connect

    Soh, R; Lee, J; Harianto, F

    2014-06-01

    Purpose: To determine and compare the correction factors obtained for TLDs in 2 × 2cm{sup 2} small field in lung heterogenous phantom using Acuros XB (AXB) and EGSnrc. Methods: This study will simulate the correction factors due to the perturbation of TLD-100 chips (Harshaw/Thermoscientific, 3 × 3 × 0.9mm{sup 3}, 2.64g/cm{sup 3}) in small field lung medium for Stereotactic Body Radiation Therapy (SBRT). A physical lung phantom was simulated by a 14cm thick composite cork phantom (0.27g/cm{sup 3}, HU:-743 ± 11) sandwiched between 4cm thick Plastic Water (CIRS,Norfolk). Composite cork has been shown to be a good lung substitute material for dosimetric studies. 6MV photon beam from Varian Clinac iX (Varian Medical Systems, Palo Alto, CA) with field size 2 × 2cm{sup 2} was simulated. Depth dose profiles were obtained from the Eclipse treatment planning system Acuros XB (AXB) and independently from DOSxyznrc, EGSnrc. Correction factors was calculated by the ratio of unperturbed to perturbed dose. Since AXB has limitations in simulating actual material compositions, EGSnrc will also simulate the AXB-based material composition for comparison to the actual lung phantom. Results: TLD-100, with its finite size and relatively high density, causes significant perturbation in 2 × 2cm{sup 2} small field in a low lung density phantom. Correction factors calculated by both EGSnrc and AXB was found to be as low as 0.9. It is expected that the correction factor obtained by EGSnrc wlll be more accurate as it is able to simulate the actual phantom material compositions. AXB have a limited material library, therefore it only approximates the composition of TLD, Composite cork and Plastic water, contributing to uncertainties in TLD correction factors. Conclusion: It is expected that the correction factors obtained by EGSnrc will be more accurate. Studies will be done to investigate the correction factors for higher energies where perturbation may be more pronounced.

  1. Field calibration of multi-scattering correction factor for aethalometer aerosol absorption coefficient during CAPMEX Campaign, 2008

    NASA Astrophysics Data System (ADS)

    Kim, J. H.; Kim, S. W.; Yoon, S. C.; Park, R.; Ogren, J. A.

    2014-12-01

    Filter-based instrument, such as aethalometer, is being widely used to measure equivalent black carbon(EBC) mass concentration and aerosol absorption coefficient(AAC). However, many other previous studies have poited that AAC and its aerosol absorption angstrom exponent(AAE) are strongly affected by the multi-scattering correction factor(C) when we retrieve AAC from aethalometer EBC mass concentration measurement(Weingartner et al., 2003; Arnott et al., 2005; Schmid et al., 2006; Coen et al., 2010). We determined the C value using the method given in Weingartner et al. (2003) by comparing 7-wavelngth aethalometer (AE-31, Magee sci.) to 3-wavelength Photo-Acoustic Soot Spectrometer (PASS-3, DMT) at Gosan climate observatory, Korea(GCO) during Cheju ABC plume-asian monsoon experiment(CAPMEX) campaign(August and September, 2008). In this study, C was estimated to be 4.04 ± 1.68 at 532 nm and AAC retrieved with this value was decreased as approximately 100% as than that retrieved with soot case value from Weingartner et al (2003). We compared the AAC determined from aethalomter measurements to that from collocated Continuous Light Absorption Photometer (CLAP) measurements from January 2012 to December 2013 at GCO and found good agreement in both AAC and AAE. This result suggests the determination of site-specific C is crucially needed when we calculate AAC from aethalometer measurements.

  2. An algorithm for temperature correcting substrate moisture measurements: aligning substrate moisture responses with environmental drivers in polytunnel-grown strawberry plants

    NASA Astrophysics Data System (ADS)

    Goodchild, Martin; Janes, Stuart; Jenkins, Malcolm; Nicholl, Chris; Kühn, Karl

    2015-04-01

    The aim of this work is to assess the use of temperature corrected substrate moisture data to improve the relationship between environmental drivers and the measurement of substrate moisture content in high porosity soil-free growing environments such as coir. Substrate moisture sensor data collected from strawberry plants grown in coir bags installed in a table-top system under a polytunnel illustrates the impact of temperature on capacitance-based moisture measurements. Substrate moisture measurements made in our coir arrangement possess the negative temperature coefficient of the permittivity of water where diurnal changes in moisture content oppose those of substrate temperature. The diurnal substrate temperature variation was seen to range from 7° C to 25° C resulting in a clearly observable temperature effect in substrate moisture content measurements during the 23 day test period. In the laboratory we measured the ML3 soil moisture sensor (ThetaProbe) response to temperature in Air, dry glass beads and water saturated glass beads and used a three-phase alpha (α) mixing model, also known as the Complex Refractive Index Model (CRIM), to derive the permittivity temperature coefficients for glass and water. We derived the α value and estimated the temperature coefficient for water - for sensors operating at 100MHz. Both results are good agreement with published data. By applying the CRIM equation with the temperature coefficients of glass and water the moisture temperature coefficient of saturated glass beads has been reduced by more than an order of magnitude to a moisture temperature coefficient of

  3. Factors affecting quality of temperature models for the pre-appearance interval of forensically useful insects.

    PubMed

    Matuszewski, Szymon; Mądra, Anna

    2015-02-01

    In the case of many forensically important insects an interval preceding appearance of an insect stage on a corpse (called the pre-appearance interval or PAI) is strongly temperature-dependent. Accordingly, it was proposed to estimate PAI from temperature by using temperature models for PAI of particular insect species and temperature data specific for a given case. The quality of temperature models for PAI depends on the protocols for PAI field studies. In this article we analyze effects of sampling frequency and techniques, temperature data, as well as the size of a sample on the quality of PAI models. Models were created by using data from a largely replicated PAI field study, and their performance in estimation was tested with external body of PAI data. It was found that low frequency of insect sampling distinctly deteriorated temperature models for PAI. The effect of sampling techniques was clearly smaller. Temperature data from local weather station gave models of poor quality, however their retrospective correction clearly improved the models. Most importantly, current results demonstrate that sample size in PAI field studies may be substantially reduced, with no model deterioration. Samples consisting of 11-14 carcasses gave models of high quality, as long as the whole range of relevant temperatures was studied. Moreover, it was found that carcasses exposed in forests and carcasses exposed in early spring are particularly important, as they ensure that PAI data is collected at low temperatures. A preliminary best practice model for PAI field studies is given. PMID:25541074

  4. Temperature dependence of the electron Landé g-factor in cubic GaN

    NASA Astrophysics Data System (ADS)

    Buß, J. H.; Schupp, T.; As, D. J.; Hägele, D.; Rudolph, J.

    2015-12-01

    The temperature dependence of the electron Landé g-factor in bulk cubic GaN is investigated over an extremely broad temperature range from 15 K up to 500 K by time-resolved Kerr-rotation spectroscopy. The g-factor is found to be approximately constant over the full investigated temperature range. Calculations by k .p -theory predict a negligible temperature dependence g(T) in complete agreement with the experiment as a consequence of the large band-gap and small spin orbit splitting in cubic GaN.

  5. Low temperature coefficient of resistance and high gage factor in beryllium-doped silicon

    NASA Technical Reports Server (NTRS)

    Robertson, J. B.; Littlejohn, M. A.

    1974-01-01

    The gage factor and resistivity of p-type silicon doped with beryllium was studied as a function of temperature, crystal orientation, and beryllium doping concentration. It was shown that the temperature coefficient of resistance can be varied and reduced to zero near room temperature by varying the beryllium doping level. Similarly, the magnitude of the piezoresistance gage factor for beryllium-doped silicon is slightly larger than for silicon doped with a shallow acceptor impurity such as boron, whereas the temperature coefficient of piezoresistance is about the same for material containing these two dopants. These results are discussed in terms of a model for the piezoresistance of compensated p-type silicon.

  6. Satellite-Derived Bias-Corrected Air Temperature for Understanding Crop-Climate Interactions in Tropical Agricultural Systems

    NASA Astrophysics Data System (ADS)

    Cohn, A.

    2015-12-01

    The magnitude of local/regional temperature variability and crop responses to such changes must be well understood to accurately assess the impacts of climate variability and change on agriculture. Challenges arise when meteorological stations are sparsely distributed such as in much of the tropics including cerrado Brazil—one of the largest agriculturally-important areas in the tropics. Currently available gridded climate datasets are coarse (i.e. 2.5º to 0.5º), heavily-interpolated and hence not adequate for regional/local scale assessments of agricultural impacts from climate. In this context, we aim to develop a new method for gridded standard retrieval of a number of agriculturally-relevant near-surface air temperature indicators. We employ Moderate Resolution Imaging Spectroradiometer (MODIS)-derived land surface temperature, vertical temperature profile, meteorological station data, and other biophysical data. We will contrast the accuracy of different air temperature derivation approaches including multiple linear regression, machine learning, the use of vegetation indices to proxy for air temperature variation, and physical approaches based on surface energy balance parametrizations. Our method aims to control for potential biases in surface temperatures due to differences in land cover types, changes in vegetation cover, and variation in plant growth. Satellite-derived near-surface air temperature datasets can support enhanced analysis of climate impacts and climate change adaptation in tropical agriculture.

  7. Correction of the equilibrium temperature caused by slight evaporation of water in protein crystal growth cells during long-term space experiments at International Space Station.

    PubMed

    Fujiwara, Takahisa; Suzuki, Yoshihisa; Yoshizaki, Izumi; Tsukamoto, Katsuo; Murayama, Kenta; Fukuyama, Seijiro; Hosokawa, Kouhei; Oshi, Kentaro; Ito, Daisuke; Yamazaki, Tomoya; Tachibana, Masaru; Miura, Hitoshi

    2015-08-01

    The normal growth rates of the {110} faces of tetragonal hen egg-white lysozyme crystals, R, were measured as a function of the supersaturation σ parameter using a reflection type interferometer under μG at the International Space Station (NanoStep Project). Since water slightly evaporated from in situ observation cells during a long-term space station experiment for several months, equilibrium temperature T(e) changed, and the actual σ, however, significantly increased mainly due to the increase in salt concentration C(s). To correct σ, the actual C(s) and protein concentration C(p), which correctly represent the measured T(e) value in space, were first calculated. Second, a new solubility curve with the corrected C(s) was plotted. Finally, the revised σ was obtained from the new solubility curve. This correction method successfully revealed that the 2.8% water was evaporated from the solution, leading to 2.8% increase in the C(s) and C(p) of the solution. PMID:26329200

  8. Correction of the equilibrium temperature caused by slight evaporation of water in protein crystal growth cells during long-term space experiments at International Space Station.

    PubMed

    Fujiwara, Takahisa; Suzuki, Yoshihisa; Yoshizaki, Izumi; Tsukamoto, Katsuo; Murayama, Kenta; Fukuyama, Seijiro; Hosokawa, Kouhei; Oshi, Kentaro; Ito, Daisuke; Yamazaki, Tomoya; Tachibana, Masaru; Miura, Hitoshi

    2015-08-01

    The normal growth rates of the {110} faces of tetragonal hen egg-white lysozyme crystals, R, were measured as a function of the supersaturation σ parameter using a reflection type interferometer under μG at the International Space Station (NanoStep Project). Since water slightly evaporated from in situ observation cells during a long-term space station experiment for several months, equilibrium temperature T(e) changed, and the actual σ, however, significantly increased mainly due to the increase in salt concentration C(s). To correct σ, the actual C(s) and protein concentration C(p), which correctly represent the measured T(e) value in space, were first calculated. Second, a new solubility curve with the corrected C(s) was plotted. Finally, the revised σ was obtained from the new solubility curve. This correction method successfully revealed that the 2.8% water was evaporated from the solution, leading to 2.8% increase in the C(s) and C(p) of the solution.

  9. Political Correctness--Correct?

    ERIC Educational Resources Information Center

    Boase, Paul H.

    1993-01-01

    Examines the phenomenon of political correctness, its roots and objectives, and its successes and failures in coping with the conflicts and clashes of multicultural campuses. Argues that speech codes indicate failure in academia's primary mission to civilize and educate through talk, discussion, thought,166 and persuasion. (SR)

  10. Ultraviolet Rayleigh-Mie lidar with Mie-scattering correction by Fabry-Perot etalons for temperature profiling of the troposphere.

    PubMed

    Hua, Dengxin; Uchida, Masaru; Kobayashi, Takao

    2005-03-01

    A Rayleigh-Mie-scattering lidar system at an eye-safe 355-nm ultraviolet wavelength that is based on a high-spectral-resolution lidar technique is demonstrated for measuring the vertical temperature profile of the troposphere. Two Rayleigh signals, which determine the atmospheric temperature, are filtered with two Fabry-Perot etalon filters. The filters are located on the same side of the wings of the Rayleigh-scattering spectrum and are optically constructed with a dual-pass optical layout. This configuration achieves a high rejection rate for Mie scattering and reasonable transmission for Rayleigh scattering. The Mie signal is detected with a third Fabry-Perot etalon filter, which is centered at the laser frequency. The filter parameters were optimized by numerical calculation; the results showed a Mie rejection of approximately -45 dB, and Rayleigh transmittance greater than 1% could be achieved for the two Rayleigh channels. A Mie correction method is demonstrated that uses an independent measure of the aerosol scattering to correct the temperature measurements that have been influenced by the aerosols and clouds. Simulations and preliminary experiments have demonstrated that the performance of the dual-pass etalon and Mie correction method is highly effective in practical applications. Simulation results have shown that the temperature errors that are due to noise are less than 1 K up to a height of 4 km for daytime measurement for 300 W m(-2) sr(-1) microm(-1) sky brightness with a lidar system that uses 200 mJ of laser energy, a 3.5-min integration time, and a 25-cm telescope.

  11. Constraints on hard spectator scattering and annihilation corrections in Bu,d → PV decays within QCD factorization

    NASA Astrophysics Data System (ADS)

    Sun, Junfeng; Chang, Qin; Hu, Xiaohui; Yang, Yueling

    2015-04-01

    In this paper, we investigate the contributions of hard spectator scattering and annihilation in B → PV decays within the QCD factorization framework. With available experimental data on B → πK* , ρK , πρ and Kϕ decays, comprehensive χ2 analyses of the parameters XA,Hi,f (ρA,Hi,f, ϕA,Hi,f) are performed, where XAf (XAi) and XH are used to parameterize the endpoint divergences of the (non)factorizable annihilation and hard spectator scattering amplitudes, respectively. Based on χ2 analyses, it is observed that (1) The topology-dependent parameterization scheme is feasible for B → PV decays; (2) At the current accuracy of experimental measurements and theoretical evaluations, XH = XAi is allowed by B → PV decays, but XH ≠ XAf at 68% C.L.; (3) With the simplification XH = XAi, parameters XAf and XAi should be treated individually. The above-described findings are very similar to those obtained from B → PP decays. Numerically, for B → PV decays, we obtain (ρA,Hi ,ϕA,Hi [ ° ]) = (2.87-1.95+0.66 , -145-21+14) and (ρAf, ϕAf [ ° ]) = (0.91-0.13+0.12 , -37-9+10) at 68% C.L. With the best-fit values, most of the theoretical results are in good agreement with the experimental data within errors. However, significant corrections to the color-suppressed tree amplitude α2 related to a large ρH result in the wrong sign for ACPdir (B- →π0K*-) compared with the most recent BABAR data, which presents a new obstacle in solving "ππ" and "πK" puzzles through α2. A crosscheck with measurements at Belle (or Belle II) and LHCb, which offer higher precision, is urgently expected to confirm or refute such possible mismatch.

  12. Finite-size corrections to scaling of the magnetization distribution in the two-dimensional X Y model at zero temperature

    NASA Astrophysics Data System (ADS)

    Palma, G.; Niedermayer, F.; Rácz, Z.; Riveros, A.; Zambrano, D.

    2016-08-01

    The zero-temperature, classical X Y model on an L ×L square lattice is studied by exploring the distribution ΦL(y ) of its centered and normalized magnetization y in the large-L limit. An integral representation of the cumulant generating function, known from earlier works, is used for the numerical evaluation of ΦL(y ) , and the limit distribution ΦL →∞(y ) =Φ0(y ) is obtained with high precision. The two leading finite-size corrections ΦL(y ) -Φ0(y ) ≈a1(L ) Φ1(y ) +a2(L ) Φ2(y ) are also extracted both from numerics and from analytic calculations. We find that the amplitude a1(L ) scales as ln(L /L0) /L2 and the shape correction function Φ1(y ) can be expressed through the low-order derivatives of the limit distribution, Φ1(y ) =[yΦ0(y ) +Φ0'(y ) ] ' . Thus, Φ1(y ) carries the same universal features as the limit distribution and can be used for consistency checks of universality claims based on finite-size systems. The second finite-size correction has an amplitude a2(L ) ∝1 /L2 and one finds that a2Φ2(y ) ≪a1Φ1(y ) already for small system size (L >10 ). We illustrate the feasibility of observing the calculated finite-size corrections by performing simulations of the X Y model at low temperatures, including T =0 .

  13. A physically based algorithm for non-blackbody correction of the cloud top temperature for the convective clouds

    NASA Astrophysics Data System (ADS)

    Wang, C.; Luo, Z. J.; Chen, X.; Zeng, X.; Tao, W.; Huang, X.

    2012-12-01

    Cloud top temperature is a key parameter to retrieval in the remote sensing of convective clouds. Passive remote sensing cannot directly measure the temperature at the cloud tops. Here we explore a synergistic way of estimating cloud top temperature by making use of the simultaneous passive and active remote sensing of clouds (in this case, CloudSat and MODIS). Weighting function of the MODIS 11μm band is explicitly calculated by feeding cloud hydrometer profiles from CloudSat retrievals and temperature and humidity profiles based on ECMWF ERA-interim reanalysis into a radiation transfer model. Among 19,699 tropical deep convective clouds observed by the CloudSat in 2008, the averaged effective emission level (EEL, where the weighting function attains its maximum) is at optical depth 0.91 with a standard deviation of 0.33. Furthermore, the vertical gradient of CloudSat radar reflectivity, an indicator of the fuzziness of convective cloud top, is linearly proportional to, d_{CTH-EEL}, the distance between the EEL of 11μm channel and cloud top height (CTH) determined by the CloudSat when d_{CTH-EEL}<0.6km. Beyond 0.6km, the distance has little sensitivity to the vertical gradient of CloudSat radar reflectivity. Based on these findings, we derive a formula between the fuzziness in the cloud top region, which is measurable by CloudSat, and the MODIS 11μm brightness temperature assuming that the difference between effective emission temperature and the 11μm brightness temperature is proportional to the cloud top fuzziness. This formula is verified using the simulated deep convective cloud profiles by the Goddard Cumulus Ensemble model. We further discuss the application of this formula in estimating cloud top buoyancy as well as the error characteristics of the radiative calculation within such deep-convective clouds.

  14. Three-loop radiative-recoil corrections to hyperfine splitting generated by one-loop fermion factors

    SciTech Connect

    Eides, Michael I.; Grotch, Howard; Shelyuto, Valery A.

    2004-10-01

    We consider three-loop radiative-recoil corrections to hyperfine splitting in muonium generated by diagrams with one-loop radiative photon insertions both in the electron and muon lines. An analytic result for these nonlogarithmic corrections of order {alpha}(Z{sup 2}{alpha})(Z{alpha})(m/M)E{sub F} is obtained. This result constitutes a next step in the implementation of the program of reduction of the theoretical uncertainty of hyperfine splitting below 10 Hz.

  15. [Measuring body temperature in dairy cows--applications and influencing factors].

    PubMed

    Burfeind, O; Suthar, V; Heuwieser, W

    2013-01-01

    Measuring body temperature plays an integral role in early puerperal cow monitoring programs. Furthermore, body temperature is part of the definition of puerperal metritis. Antibiotic treatment decisions are based on body temperature in several international publications on intervention strategies widely adopted in the modern dairy industry. The objective of this article is to provide a brief overview of the most recent publications on this important criterion. Several factors can influence the measurement of the body temperature (type of thermometer, insertion depth, skills of the investigator) as well as the cow's body temperature (days in milk, parity, time of the day, climate at calving). Furthermore, the occurrence of increased body temperature in healthy cows was demonstrated independently by several investigations. In ambiguous cases (e.g. raised body temperature as the only symptom) results should be interpreted with caution.

  16. Effects of temperature factor of cone nose-tip on a transition to turbulence

    NASA Astrophysics Data System (ADS)

    Bountin, D. A.; Gromyko, Yu. V.; Polivanov, P. A.; Sidorenko, A. A.; Nastobursky, A. S.; Maslov, A. A.

    2016-10-01

    During the flight of a hypersonic vehicle the areas of local heating of the surface can appear due to various reasons: the local separation zone, the incident shock wave, the joints of different materials and so forth. These areas change the temperature factor, i.e. the ratio of the surface temperature to the recovery temperature. Previous studies have shown that a local change of the temperature factor strongly influences the position of the laminar-turbulent transition in hypersonic boundary layer [1]. It was also shown that the degree of this effect depends on the position of the local heating/cooling area of the model surface. The leading edge or nose-tip of the model is an important area where the processes of receptivity occur. Disturbances converted to inner pulsation of the boundary layer is gradually increasing downstream, provoking non-linear processes, resulting in a laminar-turbulent transition. It is well known that the bluntness of model-tip substantially shifts transition position downstream. On the other hand the biggest heat loads occurs in the area of nose of reentry vehicle sufficiently changing temperature of nose-tip. Behavior of disturbances when changing the temperature factor of a blunt nose has not yet been investigated. In this paper the effect of temperature factor of blunt nose-tip change on the development of the perturbation of the boundary layer and the position of the transition was studied.

  17. The Effect of Temperature Dependent Frequency Factor on the Evaluated Trapping Parameters of TSL Glow Curves

    NASA Astrophysics Data System (ADS)

    Yazici, A. N.; Öztürk, Z.

    1998-01-01

    The effect of temperature dependency on frequency factor and its relationship to trapping parameters is discussed by using the peak shape method. The coefficients appearing in the peak shape formula for the calculation of the activation energy have been determined and tabulated for the symmetry factor mg(X) for x=0.50 and 0.75 of the peak intensity. It is found that significant errors occur in the value of the trapping parameters if the temperature dependecy of the frequency factor is not consider.

  18. Dose conversion and wall correction factors for Fricke dosimetry in high-energy photon beams: analytical model and Monte Carlo calculations.

    PubMed

    Ma, C M; Nahum, A E

    1993-01-01

    This paper presents the dose conversion and wall correction factors for Fricke dosimetry in high-energy photon beams calculated using both an analytical general cavity model and Monte Carlo techniques. The conversion factor is calculated as the ratio of the absorbed dose in water to that in the Fricke dosimeter solution with a water-walled vessel. The wall correction factor accounts for the change in the absorbed dose to the dosimeter solution caused by the inhomogeneous dosimeter wall material. A usercode based on the EGS4 Monte Carlo system, with the application of a correlated sampling variance reduction technique, has been employed in the calculations of these factors and the parameters used in the cavity model. Good agreement has been achieved between the predictions of the model and that obtained by direct Monte Carlo simulation and also with other workers' experiments. It is shown that Fricke dosimeters in common use cannot be considered to be 'large' detectors and therefore 'general cavity theory' should be applied in converting the dose to water. It is confirmed that plastic dosimeter vessels have a negligible wall effect. The wall correction factor for a 1 mm thick Pyrex-walled vessel varies with incident photon energy from 1.001 +/- 0.001 for a 60Co beam to 0.983 +/- 0.001 for a 24 MV (TPR(10)20 = 0.80) photon beam. This implies that previous Fricke measurements with glass-walled vessels should be re-evaluated. PMID:8426871

  19. A new method for charge-loss correction of room-temperature semiconductor detectors using digital trapezoidal pulse shaping

    NASA Astrophysics Data System (ADS)

    Nakhostin, M.; Veeramani, P.

    2012-06-01

    It is well known that semiconductor detectors operating at room temperature can be read out at high rate, with good noise performance and low sensitivity to ballistic deficit, by using trapezoidal (flat-topped) pulse shaping. Nevertheless, the energy resolution of these detectors is also affected by chargetrapping inside the detector crystal, which can not be compensated by the standard trapezoidal pulse shaping. A new digital algorithm based on trapezoidal pulse shaping, to compensate for the charge-trapping effect while minimizing the electronic noise, has been developed. The application of the pulse processing algorithm to a 5 × 5 × 1 mm3 planar Schottky CdTe detector leads to an energy resolution of 1.15% FWHM at 662 keV at room temperature, which is considerably superior to the results of the standard pulse filters.

  20. Novel, cyclic heat dissipation method for the correction of natural temperature gradients in sap flow measurements. Part 1. Theory and application.

    PubMed

    Lubczynski, Maciek W; Chavarro-Rincon, Diana; Roy, Jean

    2012-07-01

    Natural temperature gradient (NTG) can be a significant problem in thermal sap flow measurements, particularly in dry environments with sparse vegetation. To resolve this problem, we propose a novel correction method called cyclic heat dissipation (CHD) in its thermal dissipation probe (TDP) application. The CHD method is based on cyclic, switching ON/OFF power schema measurements and a three-exponential model, extrapolating measured signal to steady state thermal equilibrium. The extrapolated signal OFF represents NTG, whereas the extrapolated signal ON represents standard TDP signal, biased by NTG. Therefore, subtraction of the OFF signal from the ON signal allows defining the unbiased TDP signal, finally processed according to standard Granier calibration. The in vivo Kalahari measurements were carried out in three steps on four different tree species, first as NTG, then as standard TDP and finally in CHD mode, each step for ∼1-2 days. Afterwards, each tree was separated from its stem following modified Roberts' (1977) procedure, and CHD verification was applied. The typical NTG varying from ∼0.5 °C during night-time to -1 °C during day-time, after CHD correction, resulted in significant reduction of sap flux densities (J(p)) as compared with the standard TDP, particularly distinct for low J(p). The verification of the CHD method indicated ∼20% agreement with the reference method, largely dependent on the sapwood area estimate. The proposed CHD method offers the following advantages: (i) in contrast to any other NTG correction method, it removes NTG bias from the measured signal by using in situ, extrapolated to thermal equilibrium signal; (ii) it does not need any specific calibration making use of the standard Granier calibration; (iii) it provides a physical background to the proposed NTG correction; (iv) it allows for power savings; (v) it is not tied to TDP, and so can be adapted to other thermal methods. In its current state, the CHD data

  1. Influence of environmental factors on infrared eye temperature measurements in cattle.

    PubMed

    Church, J S; Hegadoren, P R; Paetkau, M J; Miller, C C; Regev-Shoshani, G; Schaefer, A L; Schwartzkopf-Genswein, K S

    2014-02-01

    Environmental factors were evaluated to determine potential limitations in using cattle eye temperatures obtained through infrared thermography (IRT) for early disease detection systems or in animal welfare research studies. The effects of the following factors on IRT eye temperatures in cattle and a fabricated surrogate "eye" were evaluated: camera to object distance, wind speed, camera settings (distance, emissivity, and humidity), and solar loading. Wind speed in both live animals and using a surrogate "eye" was found to decrease the IRT temperature. In the presence of ∼ 7 km/h wind, the mean IRT eye temperature decreased by 0.43 ± 0.13 °C and; at higher wind speeds (∼ 12 km/h), the temperature decreased by 0.78 ± 0.33 °C. Direct sunlight was found to increase the IRT eye temperature by 0.56 ± 0.36 °C. It was determined that environmental factors impact IRT temperature measurements significantly and therefore must be managed to ensure reproducible and accurate readings.

  2. The estimation of the time since death using temperatures recorded from the external auditory canal : Part II: Using single temperatures from this site to estimate the time since death with consideration of environmental or body "factors" that could affect the estimation.

    PubMed

    Rutty, Guy N

    2005-06-01

    In this second of two articles, single external auditory canal (EAC) temperatures from cases of suspicious deaths were used to verify the hypothesis that a single EAC temperature can be used to estimate a time since death (TSD). Two different types of thermometers were used (infrared and alcohol-in-glass) to record ambient and body temperatures, which were in turn applied to previously published algorithms without the use of corrective factors to estimate the TSD. In addition, 18 anatomical, environmental, and daily activity "factors" were investigated as to whether they may influence the temperature within the EAC and thus require the introduction of a corrective factor into an algorithm, other than one used to take into account the difference between the rectal and EAC temperature during life and after death. Of the ones examined, only head position, wind speed, daily circadian rhythm, drinking of hot drinks, and possibly mental thought were shown to influence temperature, but the difference was so small that the introduction of a corrective factor into an algorithm was considered unnecessary. Finally, this article provides a summary of both articles, with general recommendations to those who have to use a temperature recorded from the EAC in estimating a TSD.

  3. The Back Squat Part 2: Targeted Training Techniques to Correct Functional Deficits and Technical Factors that Limit Performance

    PubMed Central

    Kushner, Adam M.; Brent, Jensen L.; Schoenfeld, Brad J.; Hugentobler, Jason; Lloyd, Rhodri S.; Vermeil, Al; Chu, Donald A.; Harbin, Jason; McGill, Stuart M.; Myer, Gregory D.

    2015-01-01

    The back squat is a well-researched and widely used exercise to enhance fundamental movement competency that creates a foundation for optimal mechanical strategies during a broad range of activities. The primary commentary introduced the Back Squat Assessment (BSA): a criterion based assessment of the back squat that delineates 30 potentially observable functional deficits. This follow-up commentary provides a targeted system of training cues and exercises to supplement the BSA to guide corrective intervention. We propose a criterion driven approach to corrective exercise that can support practitioners in their goal to help individuals achieve movement competency in the back squat. PMID:26823657

  4. Active layers of high-performance lead zirconate titanate at temperatures compatible with silicon nano- and microeletronic [corrected] devices.

    PubMed

    Bretos, Iñigo; Jiménez, Ricardo; Tomczyk, Monika; Rodríguez-Castellón, Enrique; Vilarinho, Paula M; Calzada, M Lourdes

    2016-01-01

    Applications of ferroelectric materials in modern microelectronics will be greatly encouraged if the thermal incompatibility between inorganic ferroelectrics and semiconductor devices is overcome. Here, solution-processable layers of the most commercial ferroelectric compound--morphotrophic phase boundary lead zirconate titanate, namely Pb(Zr0.52Ti0.48)O3 (PZT)--are grown on silicon substrates at temperatures well below the standard CMOS process of semiconductor technology. The method, potentially transferable to a broader range of Zr:Ti ratios, is based on the addition of crystalline nanoseeds to photosensitive solutions of PZT resulting in perovskite crystallization from only 350 °C after the enhanced decomposition of metal precursors in the films by UV irradiation. A remanent polarization of 10.0 μC cm(-2) is obtained for these films that is in the order of the switching charge densities demanded for FeRAM devices. Also, a dielectric constant of ~90 is measured at zero voltage which exceeds that of current single-oxide candidates for capacitance applications. The multifunctionality of the films is additionally demonstrated by their pyroelectric and piezoelectric performance. The potential integration of PZT layers at such low fabrication temperatures may redefine the concept design of classical microelectronic devices, besides allowing inorganic ferroelectrics to enter the scene of the emerging large-area, flexible electronics.

  5. Active layers of high-performance lead zirconate titanate at temperatures compatible with silicon nano- and microeletronic [corrected] devices.

    PubMed

    Bretos, Iñigo; Jiménez, Ricardo; Tomczyk, Monika; Rodríguez-Castellón, Enrique; Vilarinho, Paula M; Calzada, M Lourdes

    2016-01-01

    Applications of ferroelectric materials in modern microelectronics will be greatly encouraged if the thermal incompatibility between inorganic ferroelectrics and semiconductor devices is overcome. Here, solution-processable layers of the most commercial ferroelectric compound--morphotrophic phase boundary lead zirconate titanate, namely Pb(Zr0.52Ti0.48)O3 (PZT)--are grown on silicon substrates at temperatures well below the standard CMOS process of semiconductor technology. The method, potentially transferable to a broader range of Zr:Ti ratios, is based on the addition of crystalline nanoseeds to photosensitive solutions of PZT resulting in perovskite crystallization from only 350 °C after the enhanced decomposition of metal precursors in the films by UV irradiation. A remanent polarization of 10.0 μC cm(-2) is obtained for these films that is in the order of the switching charge densities demanded for FeRAM devices. Also, a dielectric constant of ~90 is measured at zero voltage which exceeds that of current single-oxide candidates for capacitance applications. The multifunctionality of the films is additionally demonstrated by their pyroelectric and piezoelectric performance. The potential integration of PZT layers at such low fabrication temperatures may redefine the concept design of classical microelectronic devices, besides allowing inorganic ferroelectrics to enter the scene of the emerging large-area, flexible electronics. PMID:26837240

  6. Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation 1948--1951. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Denham, D.H.; Mart, E.I.; Thiede, M.E.

    1993-09-01

    This report is a part of the Hanford Environmental Dose Reconstruction (HEDR) Project, whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. The key radionuclide emitted that would affect the radiation dose was iodine-131 (Napier 1992). Because the early methods of measuring iodine-131 were not comparable to later techniques, conversion and correction factors are needed to convert the historical measurement data into concentration values that would be determined using today`s knowledge and technologies. This report describes the conversion and correction factors developed for reconstructing historical measurements of iodine-131 in Hanford-area vegetation, which was collected from 1948 through the end of December 1951.

  7. High-temperature measurements of Q-factor in rotated X-cut quartz resonators

    NASA Technical Reports Server (NTRS)

    Fritz, I. J.

    1981-01-01

    The Q-factors of piezoelectric resonators fabricated from natural and synthetic quartz with a 34 deg rotated X-cut orientation were measured at temperatures up to 325 C. The synthetic material, which was purified by electrolysis, retains a higher enough Q to be suitable for high temperature pressure-transducer applications, whereas the natural quartz is excessively lossy above 200 C for this application. The results are compared to results obtained previously at AT-cut resonators.

  8. Conversion and correction factors for historical measurements of Iodine-131 in Hanford-area vegetation, 1945--1947: Draft. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-05-01

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. The report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947.

  9. Identification of possible factors influencing temperatures elevation during implant site preparation with piezoelectric technique

    PubMed Central

    Lamazza, Luca; Laurito, Domenica; Lollobrigida, Marco; Brugnoletti, Orlando; Garreffa, Girolamo; De Biase, Alberto

    2014-01-01

    Summary Background Overheating during implant site preparation negatively affects the osseointegration process as well the final outcome of implant rehabilitations. Piezoelectric techniques seem to provide to a gentle implant preparation although few scientific reports have investigated the heat generation and its underlying factors. Purpose To investigate, through a proper methodological approach, the main factors influencing temperature rise during piezoelectric implant site preparation. Materials and methods Different piezoelectric tips (IM1s, IM2, P2-3, IM3, Mectron Medical Technology, Carasco, Italy) have been tested. The experimental set-up consisted in a mechanical positioning device equipped with a load cell and a fluoroptic thermometer. Results The first tip of the sequence (IM1s) generated the highest temperature increasing (ΔT). The diamond tips (IM1s and P2-3) determined higher ΔT values than the smooth tips (IM2 and IM3). Further tests with IM1s suggested that the temperature elevation during the first thirty seconds may be predictive of the maximal temperature as well as of the overall thermal impact. Conclusions Working load, working movements management and bone features resulted to be the main factors influencing temperature rise during piezoelectric implant site preparation. Irrigant temperature and clogging effect may also synergically contribute to the heat generation. PMID:25774245

  10. Temperature and donor concentration dependence of the conduction electron Lande g-factor in silicon

    SciTech Connect

    Konakov, Anton A.; Ezhevskii, Alexander A.; Soukhorukov, Andrey V.; Guseinov, Davud V.; Popkov, Sergey A.; Burdov, Vladimir A.

    2013-12-04

    Temperature and donor concentration dependence of the conduction electron g-factor in silicon has been investigated both experimentally and theoretically. We performed electron spin resonance experiments on Si samples doped with different densities of phosphorus and lithium. Theoretical consideration is based on the renormalization of the electron energy in a weak magnetic field by the interaction with possible perturbing agents, such as phonons and impurity centers. In the second-order perturbation theory interaction of the electron subsystem with the lattice vibrations as well as ionized donors results in decreasing the conduction electron g-factor, which becomes almost linear function both of temperature and impurity concentration.

  11. Finite-temperature corrections to the time-domain equations of motion for perpendicular propagation in nonuniform magnetized plasmas

    SciTech Connect

    Tierens, W.; De Zutter, D.

    2012-11-15

    In this paper we extend the new techniques of W. Tierens and D. D. Zutter, J. Comput. Phys. 231, 5144 (2012) to include finite Larmor radius effects up to second order in the Larmor radius. We limit ourselves to the case of propagation perpendicular to the background magnetic field B(vector sign){sub 0}. We show that our time-domain technique is able to produce the lowest-order Bernstein wave (a wave believed to be useful for heating fusion devices [H. P. Laqua, Plasma Phys. Controlled Fusion 49, R1 (2007)]). The discrete equations retain many of the favourable properties described in W. Tierens and D. D. Zutter, J. Comput. Phys. 231, 5144 (2012), i.e., unconditional stability and a straightforward relation between the second-order accurate continuous dispersion relation and the dispersion relation of the discretized problem. The theory is illustrated by a place-independent and a place-dependent temperature numerical example.

  12. Scattering amplitudes and static atomic correction factors for the composition-sensitive 002 reflection in sphalerite ternary III-V and II-VI semiconductors.

    PubMed

    Schowalter, M; Müller, K; Rosenauer, A

    2012-01-01

    Modified atomic scattering amplitudes (MASAs), taking into account the redistribution of charge due to bonds, and the respective correction factors considering the effect of static atomic displacements were computed for the chemically sensitive 002 reflection for ternary III-V and II-VI semiconductors. MASAs were derived from computations within the density functional theory formalism. Binary eight-atom unit cells were strained according to each strain state s (thin, intermediate, thick and fully relaxed electron microscopic specimen) and each concentration (x = 0, …, 1 in 0.01 steps), where the lattice parameters for composition x in strain state s were calculated using continuum elasticity theory. The concentration dependence was derived by computing MASAs for each of these binary cells. Correction factors for static atomic displacements were computed from relaxed atom positions by generating 50 × 50 × 50 supercells using the lattice parameter of the eight-atom unit cells. Atoms were randomly distributed according to the required composition. Polynomials were fitted to the composition dependence of the MASAs and the correction factors for the different strain states. Fit parameters are given in the paper.

  13. Correction factors for A1SL ionization chamber dosimetry in TomoTherapy: Machine-specific, plan-class, and clinical fields

    SciTech Connect

    Gago-Arias, Araceli; Rodriguez-Romero, Ruth; Sanchez-Rubio, Patricia; Miguel Gonzalez-Castano, Diego; Gomez, Faustino; Nunez, Luis; Palmans, Hugo; Sharpe, Peter; Pardo-Montero, Juan

    2012-04-15

    Purpose: Recently, an international working group on nonstandard fields presented a new formalism for ionization chamber reference dosimetry of small and nonstandard fields [Alfonso et al., Med. Phys. 35, 5179-5186 (2008)] which has been adopted by AAPM TG-148. This work presents an experimental determination of the correction factors for reference dosimetry with an Exradin A1SL thimble ionization chamber in a TomoTherapy unit, focusing on: (i) machine-specific reference field, (ii) plan-class-specific reference field, and (iii) two clinical treatments. Methods: Ionization chamber measurements were performed in the TomoTherapy unit for intermediate (machine-specific and plan-class-specific) calibration fields, based on the reference conditions defined by AAPM TG-148, and two clinical treatments (lung and head-and-neck). Alanine reference dosimetry was employed to determine absorbed dose to water at the point of interest for the fields under investigation. The corresponding chamber correction factors were calculated from alanine to ionization chamber measurements ratios. Results: Two different methods of determining the beam quality correction factor k{sub Q,Q{sub 0}} for the A1SL ionization chamber in this TomoTherapy unit, where reference conditions for conventional beam quality determination cannot be met, result in consistent values. The observed values of overall correction factors obtained for intermediate and clinical fields are consistently around 0.98 with a typical expanded relative uncertainty of 2% (k = 2), which when considered make such correction factors compatible with unity. However, all of them are systematically lower than unity, which is shown to be significant when a hypothesis test assuming a t-student distribution is performed (p=1.8x10{sup -2}). Correction factors k{sub Q{sub c{sub l{sub i{sub n,Q{sub p{sub c{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub p}{sub c}{sub s}{sub r}}}}}}}}}} and k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s

  14. Temperature: a prolonged confounding factor on cholinesterase activity in the tropical reef fish Acanthochromis polyacanthus.

    PubMed

    Botté, Emmanuelle S; Smith-Keune, Carolyn; Jerry, Dean R

    2013-09-15

    Cholinesterase activity usually decreases in fish exposed to anticholinesterase compounds such as organophosphate and carbamate pesticides. Here we show that tropical reef fish Acanthochromis polyacanthus (or spiny damsel) also exhibits a decrease in ChE activity when exposed to elevated temperature from 28°C to 32°C or 34°C after 4 days. We further demonstrate that the decline persists even after 7 days of recovery at control temperature. This is the first report of a drop in ChE activity in fish as temperature increases. Our results strongly suggest the need for long-term monitoring of water temperature in the field prior to sampling A. polyacanthus for toxicology studies, as temperature is a prolonged and confounding factor for ChE activity in this species.

  15. Factors influencing the acquisition and correct and consistent use of the top-lit updraft cookstove in Uganda.

    PubMed

    Namagembe, Allen; Muller, Nancy; Scott, Lisa Mueller; Zwisler, Greg; Johnson, Michael; Arney, Jennifer; Charron, Dana; Mugisha, Emmanuel

    2015-01-01

    This study looked at the effects of select behavior change interventions on the purchase and the correct and consistent use of a locally fabricated top-lit updraft (TLUD) stove in Uganda. Behavior change interventions included training of community sales agents and village health team volunteers on household air pollution and correct use, referral of interested community members to sales agents, community cooking demonstrations, information flyers, and direct sales of TLUDs and processed wood. Qualitative and quantitative research methods shaped interventions and were used to understand attitudes and practices related to TLUD stove acquisition and use. Results showed that TLUDs were appreciated because they use wood efficiently, cook quickly, reduce smoke, and produce charcoal. However, the substantial purchase price barrier, combined with the cost of processed wood, effectively eliminated the cost savings from its significant fuel efficiency. This made it difficult for the TLUD to be a meaningful part of most households' cooking practices. PMID:25839205

  16. Arterial to end-tidal Pco2 difference during exercise in normoxia and severe acute hypoxia: importance of blood temperature correction

    PubMed Central

    Losa-Reyna, José; Torres-Peralta, Rafael; Henriquez, Juan José González; Calbet, José A L

    2015-01-01

    Negative arterial to end-tidal Pco2 differences ((a-ET)Pco2) have been reported in normoxia. To determine the influence of blood temperature on (a-ET)Pco2, 11 volunteers (21 ± 2 years) performed incremental exercise to exhaustion in normoxia (Nx, PIo2: 143 mmHg) and hypoxia (Hyp, PIo2: 73 mmHg), while arterial blood gases and temperature (ABT) were simultaneously measured together with end-tidal Pco2 (PETco2). After accounting for blood temperature, the (a-ET) Pco2 was reduced (in absolute values) from −4.2 ± 1.6 to −1.1 ± 1.5 mmHg in normoxia and from −1.7 ± 1.6 to 0.9 ± 0.9 mmHg in hypoxia (both P < 0.05). The temperature corrected (a-ET)Pco2 was linearly related with absolute and relative exercise intensity, VO2, VCO2, and respiratory rate (RR) in normoxia and hypoxia (R2: 0.52–0.59). Exercise CO2 production and PETco2 values were lower in hypoxia than normoxia, likely explaining the greater (less negative) (a-ET)Pco2 difference in hypoxia than normoxia (P < 0.05). At near-maximal exercise intensity the (a-ET)Pco2 lies close to 0 mmHg, that is, the mean Paco2 and the mean PETco2 are similar. The mean exercise (a-ET)Pco2 difference is closely related to the mean A-aDO2 difference (r = 0.90, P < 0.001), as would be expected if similar mechanisms perturb the gas exchange of O2 and CO2 during exercise. In summary, most of the negative (a-ET)Pco2 values observed in previous studies are due to lack of correction of Paco2 for blood temperature. The absolute magnitude of the (a-ET)Pco2 difference is lower during exercise in hypoxia than normoxia. PMID:26508736

  17. Relations of Tualatin River water temperatures to natural and human-caused factors

    USGS Publications Warehouse

    Risley, John C.

    1997-01-01

    Aquatic research has long shown that the survival of cold-water fish, such as salmon and trout, decreases markedly as water temperatures increase above a critical threshold, particularly during sensitive life stages of the fish. In an effort to improve the overall health of aquatic ecosystems, the State of Oregon in 1996 adopted a maximum water-temperature standard of 17.8 degrees Celsius (68 degrees Fahrenheit), based on a 7-day moving average of daily maximum temperatures, for most water bodies in the State. Anthropogenic activities are not permitted to raise the temperature of a water body above this level. In the Tualatin River, a tributary of the Willamette River located in northwestern Oregon, water temperatures periodically surpass this threshold during the low-flow summer and fall months.An investigation by the U.S. Geological Survey quantified existing seasonal, diel, and spatial patterns of water temperatures in the main stem of the river, assessed the relation of water temperatures to natural climatic conditions and anthropogenic factors (such as wastewater-treatment-plant effluent and modification of riparian shading), and assessed the impact of various flow management practices on stream temperatures. Half-hourly temperature measurements were recorded at 13 monitoring sites from river mile (RM) 63.9 to RM 3.4 from May to November of 1994. Four synoptic water- temperature surveys also were conducted in the upstream and downstream vicinities of two wastewater-treatment-plant outfalls. Temperature and streamflow time-series data were used to calibrate two dynamic-flow heat-transfer models, DAFLOW-BLTM (RM 63.9-38.4) and CE-QUAL-W2 (RM 38.4-3.4). Simulations from the models provided a basis for approximating 'natural' historical temperature patterns, performing effluent and riparian-shading sensitivity analyses, and evaluating mitigation management scenarios under 1994 climatic conditions. Findings from the investigation included (1) under 'natural

  18. Factors contributing to the temperature beneath plaster or fiberglass cast material

    PubMed Central

    Hutchinson, Michael J; Hutchinson, Mark R

    2008-01-01

    Background Most cast materials mature and harden via an exothermic reaction. Although rare, thermal injuries secondary to casting can occur. The purpose of this study was to evaluate factors that contribute to the elevated temperature beneath a cast and, more specifically, evaluate the differences of modern casting materials including fiberglass and prefabricated splints. Methods The temperature beneath various types (plaster, fiberglass, and fiberglass splints), brands, and thickness of cast material were measured after they were applied over thermometer which was on the surface of a single diameter and thickness PVC tube. A single layer of cotton stockinette with variable layers and types of cast padding were placed prior to application of the cast. Serial temperature measurements were made as the cast matured and reached peak temperature. Time to peak, duration of peak, and peak temperature were noted. Additional tests included varying the dip water temperature and assessing external insulating factors. Ambient temperature, ambient humidity and dip water freshness were controlled. Results Outcomes revealed that material type, cast thickness, and dip water temperature played key roles regarding the temperature beneath the cast. Faster setting plasters achieved peak temperature quicker and at a higher level than slower setting plasters. Thicker fiberglass and plaster casts led to greater peak temperature levels. Likewise increasing dip-water temperature led to elevated temperatures. The thickness and type of cast padding had less of an effect for all materials. With a definition of thermal injury risk of skin injury being greater than 49 degrees Celsius, we found that thick casts of extra fast setting plaster consistently approached dangerous levels (greater than 49 degrees for an extended period). Indeed a cast of extra-fast setting plaster, 20 layers thick, placed on a pillow during maturation maintained temperatures over 50 degrees of Celsius for over 20

  19. Effects of temperature on Escherichia coli overproducing beta-lactamase or human epidermal growth factor.

    PubMed Central

    Chalmers, J J; Kim, E; Telford, J N; Wong, E Y; Tacon, W C; Shuler, M L; Wilson, D B

    1990-01-01

    The effects of temperature on strains of Escherichia coli which overproduce and excrete either beta-lactamase or human epidermal growth factor were investigated. E. coli RB791 cells containing plasmid pKN which has the tac promoter upstream of the gene for beta-lactamase were grown and induced with isopropyl-beta-D-thiogalactopyranoside in batch culture at 37, 30, 25, and 20 degrees C. The lower temperature greatly reduced the formation of periplasmic beta-lactamase inclusion bodies, increased significantly the total amount of beta-lactamase activity, and increased the purity of extracellular beta-lactamase from approximately 45 to 90%. Chemostat operation at 37 and 30 degrees C was difficult due to poor cell reproduction and beta-lactamase production. However, at 20 degrees C, continuous production and excretion of beta-lactamase were obtained for greater than 450 h (29 generations). When the same strain carried plasmid pCU encoding human epidermal growth factor, significant cell lysis was observed after induction at 31 and 37 degrees C, whereas little cell lysis was observed at 21 and 25 degrees C. Both total soluble and total human epidermal growth factor increased with decreasing temperature. These results indicate that some of the problems of instability of strains producing high levels of plasmid-encoded proteins can be mitigated by growth at lower temperatures. Further, lower temperatures can increase for at least some secreted proteins both total plasmid-encoded protein formed and the fraction that is soluble. Images PMID:2155574

  20. Temperature-Related Risk Factors for the Occurrence of Campylobacter in Broilers in Iceland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction A summertime increased risk of Campylobacter is well-established in humans and broilers. Our objective was to identify temperature-related risk factors for the colonization of broiler flocks with Campylobacter in Iceland, with an assumption that flies play a role in the epidemiology an...

  1. Temperature trumps light: Teasing apart interactive factors controlling non-indigenous Zostera japonica growth

    EPA Science Inventory

    In the Pacific Northwest Zostera marina and Z. japonica co-exist by occupying separate elevation niches. We conducted two mesocosm experiments to evaluate light and temperature as factors controlling the disjunct distribution of congeners. The first study tests the hypothesis t...

  2. A New Method to Measure Temperature and Burner Pattern Factor Sensing for Active Engine Control

    NASA Technical Reports Server (NTRS)

    Ng, Daniel

    1999-01-01

    The determination of the temperatures of extended surfaces which exhibit non-uniform temperature variation is very important for a number of applications including the "Burner Pattern Factor" (BPF) of turbine engines. Exploratory work has shown that use of BPF to control engine functions can result in many benefits, among them reduction in engine weight, reduction in operating cost, increase in engine life, while attaining maximum engine efficiency. Advanced engines are expected to operate at very high temperature to achieve high efficiency. Brief exposure of engine components to higher than design temperatures due to non-uniformity in engine burner pattern can reduce engine life. The engine BPF is a measure of engine temperature uniformity. Attainment of maximum temperature uniformity and high temperatures is key to maximum efficiency and long life. A new approach to determine through the measurement of just one radiation spectrum by a multiwavelength pyrometer is possible. This paper discusses a new temperature sensing approach and its application to determine the BPF.

  3. Factors That Affect Riverbank Filtrate Water Temperature in Daesan Plants, Changwon, Korea

    NASA Astrophysics Data System (ADS)

    Shin, J.; Lim, J.; Lee, K.; Jung, W.; Kim, H.

    2008-12-01

    City of Changwon, Korea, has been using some of riverbank filtrate water for the indoor air-conditioning of Daesan purification plants since 2006. In this method, the most important factor to determine efficiency of heating and cooling is the temperature of the filtrate water. Thus, it is required to predict the available range of groundwater temperature in the case of changing pumping rate, pumping location or in the case of long term operation. Numerical simulation of temperature profile of riverbank filtrate water in Daesan plants using HydroGeoSphere shows that the primary factor in determining filtrate water temperature is the pumping rate. Distance from the river to the wells is long enough to equalize subsurface water temperature through its penetration path and all of the well screen sections are located at the depth of 30 m below surface which is part of the local aquifer. This is why the horizontal distance from the river to each well and the installed screen depth are less important than the pumping rate to determine filtrate water temperature in this facility. It also shows that maintaining the facility operation with present pumping rate for the next 30 years will not cause any significant change of water temperature. However, following the new plan of the city to install additional 37 wells with 6 times higher pumping rate than the current rate might cause about 2? decrease in filtrate water temperature in 10 years after the extension. All of these results demonstrate that basic hydrological study such as aquifer heterogeneity or pumping capacity is prerequisite for calculating and predicting extracted water temperature in riverbank filtration system.

  4. Extrahepatic sources of factor VIII potentially contribute to the coagulation cascade correcting the bleeding phenotype of mice with hemophilia A.

    PubMed

    Zanolini, Diego; Merlin, Simone; Feola, Maria; Ranaldo, Gabriella; Amoruso, Angela; Gaidano, Gianluca; Zaffaroni, Mauro; Ferrero, Alessandro; Brunelleschi, Sandra; Valente, Guido; Gupta, Sanjeev; Prat, Maria; Follenzi, Antonia

    2015-07-01

    A large fraction of factor VIII in blood originates from liver sinusoidal endothelial cells although extrahepatic sources also contribute to plasma factor VIII levels. Identification of cell-types other than endothelial cells with the capacity to synthesize and release factor VIII will be helpful for therapeutic approaches in hemophilia A. Recent cell therapy and bone marrow transplantation studies indicated that Küpffer cells, monocytes and mesenchymal stromal cells could synthesize factor VIII in sufficient amount to ameliorate the bleeding phenotype in hemophilic mice. To further establish the role of blood cells in expressing factor VIII, we studied various types of mouse and human hematopoietic cells. We identified factor VIII in cells isolated from peripheral and cord blood, as well as bone marrow. Co-staining for cell type-specific markers verified that factor VIII was expressed in monocytes, macrophages and megakaryocytes. We additionally verified that factor VIII was expressed in liver sinusoidal endothelial cells and endothelial cells elsewhere, e.g., in the spleen, lungs and kidneys. Factor VIII was well expressed in sinusoidal endothelial cells and Küpffer cells isolated from human liver, whereas by comparison isolated human hepatocytes expressed factor VIII at very low levels. After transplantation of CD34(+) human cord blood cells into NOD/SCIDγNull-hemophilia A mice, fluorescence activated cell sorting of peripheral blood showed >40% donor cells engrafted in the majority of mice. In these animals, plasma factor VIII activity 12 weeks after cell transplantation was up to 5% and nine of 12 mice survived after a tail clip-assay. In conclusion, hematopoietic cells, in addition to endothelial cells, express and secrete factor VIII: this information should offer further opportunities for understanding mechanisms of factor VIII synthesis and replenishment.

  5. Extrahepatic sources of factor VIII potentially contribute to the coagulation cascade correcting the bleeding phenotype of mice with hemophilia A.

    PubMed

    Zanolini, Diego; Merlin, Simone; Feola, Maria; Ranaldo, Gabriella; Amoruso, Angela; Gaidano, Gianluca; Zaffaroni, Mauro; Ferrero, Alessandro; Brunelleschi, Sandra; Valente, Guido; Gupta, Sanjeev; Prat, Maria; Follenzi, Antonia

    2015-07-01

    A large fraction of factor VIII in blood originates from liver sinusoidal endothelial cells although extrahepatic sources also contribute to plasma factor VIII levels. Identification of cell-types other than endothelial cells with the capacity to synthesize and release factor VIII will be helpful for therapeutic approaches in hemophilia A. Recent cell therapy and bone marrow transplantation studies indicated that Küpffer cells, monocytes and mesenchymal stromal cells could synthesize factor VIII in sufficient amount to ameliorate the bleeding phenotype in hemophilic mice. To further establish the role of blood cells in expressing factor VIII, we studied various types of mouse and human hematopoietic cells. We identified factor VIII in cells isolated from peripheral and cord blood, as well as bone marrow. Co-staining for cell type-specific markers verified that factor VIII was expressed in monocytes, macrophages and megakaryocytes. We additionally verified that factor VIII was expressed in liver sinusoidal endothelial cells and endothelial cells elsewhere, e.g., in the spleen, lungs and kidneys. Factor VIII was well expressed in sinusoidal endothelial cells and Küpffer cells isolated from human liver, whereas by comparison isolated human hepatocytes expressed factor VIII at very low levels. After transplantation of CD34(+) human cord blood cells into NOD/SCIDγNull-hemophilia A mice, fluorescence activated cell sorting of peripheral blood showed >40% donor cells engrafted in the majority of mice. In these animals, plasma factor VIII activity 12 weeks after cell transplantation was up to 5% and nine of 12 mice survived after a tail clip-assay. In conclusion, hematopoietic cells, in addition to endothelial cells, express and secrete factor VIII: this information should offer further opportunities for understanding mechanisms of factor VIII synthesis and replenishment. PMID:25911555

  6. High Temperature as a Risk Factor for Infectious Diarrhea in Shanghai, China

    PubMed Central

    Zhou, Xiaodan; Zhou, Yanbing; Chen, Renjie; Ma, Wenjuan; Deng, Haiju; Kan, Haidong

    2013-01-01

    Background Recent studies indicate that ambient temperature could be a risk factor for infectious diarrhea, but evidence for such a relation is limited in China. Methods We investigated the short-term association between daily temperature and physician-diagnosed infectious diarrhea during 2008–2010 in Shanghai, China. We adopted a time-series approach to analyze the data and a quasi-Poisson regression model with a natural spline-smoothing function to adjust for long-term and seasonal trends, as well as other time-varying covariates. Results There was a significant association between temperature and outpatient visits for diarrhea. A 1°C increase in the 6-day moving average of temperature was associated with a 2.68% (95% CI: 1.83%, 3.52%) increase in outpatient visits for diarrhea. We did not find a significant association between rainfall and infectious diarrhea. Conclusions High temperature might be a risk factor for infectious diarrhea in Shanghai. Public health programs should focus on preventing diarrhea related to high temperature among city residents. PMID:23994865

  7. PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) regulates auxin biosynthesis at high temperature

    PubMed Central

    Franklin, Keara A.; Lee, Sang Ho; Patel, Dhaval; Kumar, S. Vinod; Spartz, Angela K.; Gu, Chen; Ye, Songqing; Yu, Peng; Breen, Gordon; Cohen, Jerry D.; Wigge, Philip A.; Gray, William M.

    2011-01-01

    At high ambient temperature, plants display dramatic stem elongation in an adaptive response to heat. This response is mediated by elevated levels of the phytohormone auxin and requires auxin biosynthesis, signaling, and transport pathways. The mechanisms by which higher temperature results in greater auxin accumulation are unknown, however. A basic helix-loop-helix transcription factor, PHYTOCHROME-INTERACTING FACTOR 4 (PIF4), is also required for hypocotyl elongation in response to high temperature. PIF4 also acts redundantly with its homolog, PIF5, to regulate diurnal growth rhythms and elongation responses to the threat of vegetative shade. PIF4 activity is reportedly limited in part by binding to both the basic helix-loop-helix protein LONG HYPOCOTYL IN FAR RED 1 and the DELLA family of growth-repressing proteins. Despite the importance of PIF4 in integrating multiple environmental signals, the mechanisms by which PIF4 controls growth are unknown. Here we demonstrate that PIF4 regulates levels of auxin and the expression of key auxin biosynthesis genes at high temperature. We also identify a family of SMALL AUXIN UP RNA (SAUR) genes that are expressed at high temperature in a PIF4-dependent manner and promote elongation growth. Taken together, our results demonstrate direct molecular links among PIF4, auxin, and elongation growth at high temperature. PMID:22123947

  8. Evaluation of weldment creep and fatigue strength-reduction factors for elevated-temperature design

    SciTech Connect

    Corum, J.M.

    1989-01-01

    New explicit weldment strength criteria in the form of creep and fatigue strength-reduction factors were recently introduced into the American Society of Mechanical Engineers Code Case N-47, which governs the design of elevated-temperature nuclear plants components in the United States. This paper provides some of the background and logic for these factors and their use, and it describes the results of a series of long-term, confirmatory, creep-rupture and fatigue tests of simple welded structures. The structures (welded plates and tubes) were made of 316 stainless steel base metal and 16-8-2 weld filler metal. Overall, the results provide further substantiation of the validity of the strength-reduction factor approach for ensuring adequate life in elevated-temperature nuclear component weldments. 16 refs., 7 figs.

  9. Factors associated with survival in the herd for dairy cows following surgery to correct left displaced abomasum.

    PubMed

    Reynen, Jennifer L; Kelton, David F; LeBlanc, Stephen J; Newby, Nathalie C; Duffield, Todd F

    2015-06-01

    Left displaced abomasum (LDA) is a common problem in dairy cows. There have been numerous studies focused on predicting prognosis for right displaced abomasal corrective surgery, but a paucity of studies exist focused on more common LDA surgeries. Our objective was to determine if survival to 60 d or 1 yr after surgery could be predicted from the physical exam findings, periparturient disease status, and a biochemical profile from a blood sample obtained at the time of LDA diagnosis. Blood β-hydroxybutyrate (BHBA) concentrations were measured immediately using a hand-held meter. Data obtained from CanWest DHI (Guelph, ON, Canada) for all of the study subjects (n=179 cases, by 24 veterinarians from 4 clinics), including cull date, cull reason, and test-day milk production. Cows were classified based on whether or not they were culled within 60 d or 1 yr of surgery. Based on logistic regression, cows that had dystocia [odds ratio (OR)=13, 95% confidence interval (CI)=7-26] or were not ketotic (blood BHBA<1.2 mmol/L; OR=3, 95% CI=1.03-9) at the time of corrective surgery were more likely to be culled within 60 d. Higher serum concentrations of BHBA (OR=0.95, 95% CI=0.92-0.98), nonesterified fatty acids (OR=0.81, 95% CI=0.75-0.88), and Mg (OR=0.49, 95% CI=0.35-0.68) all had a protective effect against culling within 1 yr of LDA surgery. Based on survival analysis, longevity in the herd for 365 d following corrective surgery was associated with higher BHBA and Mg at the time of LDA diagnosis before surgery, as well as milk production following surgery. PMID:25892696

  10. Induction temperature of human heat shock factor is reprogrammed in a Drosophila cell environment

    NASA Astrophysics Data System (ADS)

    Clos, Joachim; Rabindran, Sridhar; Wisniewski, Jan; Wu, Carl

    1993-07-01

    HEAT shock factor (HSF)1,2, the transcriptional activator of eukaryotic heat shock genes, is induced to bind DNA by a monomer to trimer transition involving leucine zipper interactions3,4. Although this mode of regulation is shared among many eukaryotic species, there is variation in the temperature at which HSF binding activity is induced. We investigated the basis of this variation by analysing the response of a human HSF expressed in Drosophila cells and Drosophila HSF expressed in human cells. We report here that the temperature that induces DNA binding and trimerization of human HSF in Drosophila was decreased by ~10 °C to the induction temperature for the host cell, whereas Drosophila HSF expressed in human cells was constitutively active. The results indicate that the activity of HSF in vivo is not a simple function of the absolute environmental temperature.

  11. Thermal dose and time-temperature factors for biological responses to heat shock.

    PubMed

    Gerner, E W

    1987-01-01

    The application of hyperthermia in human cancer therapy, especially by radiotherapists who are accustomed to prescribing ionizing radiation treatments in physical dose units, has stimulated workers in this area to consider the possibility and utility of defining a unit of 'thermal dose'. Previous thermal dose definitions have, primarily, been based on biological isoeffect response relationships, which attempt to relate exposure times that elicit a given biological response at one temperature to exposure times at another temperature that elicit the same biological response. This 'equivalent time' method is shown to have certain limitations. For both 42.4 and 45 degrees C hyperthermia, these relationships accurately describe cell survival responses only when the heating rate is rapid (greater than 0.5 degrees C min-1 from ambient to hyperthermic temperature). Further, the form of these isoeffect relationships appears to be temperature range and cell/tissue-type dependent, and it is suggested that these relationships be referred to as a 'time-temperature factor' (TTF) to help distinguish them from possible physical thermal dose definitions. Two physical dose definitions are discussed, one being simply exposure time at some temperature and the other being a more fundamental definition, the free energy change which is a temperature-dependent driving force for chemical reactions.

  12. Neonatal helper-dependent adenoviral vector gene therapy mediates correction of hemophilia A and tolerance to human factor VIII

    PubMed Central

    Cela, Racel G.; Suzuki, Masataka; Lee, Brendan; Lipshutz, Gerald S.

    2011-01-01

    Neonatal gene therapy is a promising strategy for treating a number of congenital diseases diagnosed shortly after birth as expression of therapeutic proteins during postnatal life may limit the pathologic consequences and result in a potential “cure.” Hemophilia A is often complicated by the development of antibodies to recombinant protein resulting in treatment failure. Neonatal administration of vectors may avoid inhibitory antibody formation to factor VIII (FVIII) by taking advantage of immune immaturity. A helper-dependent adenoviral vector expressing human factor VIII was administered i.v. to neonatal hemophilia A knockout mice. Three days later, mice produced high levels of FVIII. Levels declined rapidly with animal growth to 5 wk of age with stable factor VIII expression thereafter to >1 y of age. Decline in factor VIII expression was not related to cell-mediated or humoral responses with lack of development of antibodies to capsid or human factor VIII proteins. Subsequent readministration and augmentation of expression was possible as operational tolerance was established to factor VIII without development of inhibitors; however, protective immunity to adenovirus remained. PMID:21245323

  13. Assessment of the Appalachian Basin Geothermal Field: Combining Risk Factors to Inform Development of Low Temperature Projects

    NASA Astrophysics Data System (ADS)

    Smith, J. D.; Whealton, C.; Camp, E. R.; Horowitz, F.; Frone, Z. S.; Jordan, T. E.; Stedinger, J. R.

    2015-12-01

    Exploration methods for deep geothermal energy projects must primarily consider whether or not a location has favorable thermal resources. Even where the thermal field is favorable, other factors may impede project development and success. A combined analysis of these factors and their uncertainty is a strategy for moving geothermal energy proposals forward from the exploration phase at the scale of a basin to the scale of a project, and further to design of geothermal systems. For a Department of Energy Geothermal Play Fairway Analysis we assessed quality metrics, which we call risk factors, in the Appalachian Basin of New York, Pennsylvania, and West Virginia. These included 1) thermal field variability, 2) productivity of natural reservoirs from which to extract heat, 3) potential for induced seismicity, and 4) presence of thermal utilization centers. The thermal field was determined using a 1D heat flow model for 13,400 bottomhole temperatures (BHT) from oil and gas wells. Steps included the development of i) a set of corrections to BHT data and ii) depth models of conductivity stratigraphy at each borehole based on generalized stratigraphy that was verified for a select set of wells. Wells are control points in a spatial statistical analysis that resulted in maps of the predicted mean thermal field properties and of the standard error of the predicted mean. Seismic risk was analyzed by comparing earthquakes and stress orientations in the basin to gravity and magnetic potential field edges at depth. Major edges in the potential fields served as interpolation boundaries for the thermal maps (Figure 1). Natural reservoirs were identified from published studies, and productivity was determined based on the expected permeability and dimensions of each reservoir. Visualizing the natural reservoirs and population centers on a map of the thermal field communicates options for viable pilot sites and project designs (Figure 1). Furthermore, combining the four risk

  14. Spatial downscaling and correction of precipitation and temperature time series to high resolution hydrological response units in the Canadian Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Kienzle, Stefan

    2015-04-01

    Precipitation is the central driving force of most hydrological processes, and is also the most variable element of the hydrological cycle. As the precipitation to runoff ratio is non-linear, errors in precipitation estimations are amplified in streamflow simulations. Therefore, the accurate estimate of areal precipitation is essential for watershed models and relevant impacts studies. A procedure is presented to demonstrate the spatial distribution of daily precipitation and temperature estimates across the Rocky Mountains within the framework of the ACRU agro-hydrological modelling system (ACRU). ACRU (Schulze, 1995) is a physical-conceptual, semi-distributed hydrological modelling system designed to be responsive to changes in land use and climate. The model has been updated to include specific high-mountain and cold climate routines and is applied to simulate impacts of land cover and climate change on the hydrological behaviour of numerous Rocky Mountain watersheds in Alberta, Canada. Both air temperature and precipitation time series need to be downscaled to hydrological response units (HRUs), as they are the spatial modelling units for the model. The estimation of accurate daily air temperatures is critical for the separation of rain and snow. The precipitation estimation procedure integrates a spatially distributed daily precipitation database for the period 1950 to 2010 at a scale of 10 by 10 km with a 1971-2000 climate normal database available at 2 by 2 km (PRISM). Resulting daily precipitation time series are further downscaled to the spatial resolution of hydrological response units, defined by 100 m elevation bands, land cover, and solar radiation, which have an average size of about 15 km2. As snow measurements are known to have a potential under-catch of up to 40%, further adjustment of snowfall may need to be increased using a procedure by Richter (1995). Finally, precipitation input to HRUs with slopes steeper than 10% need to be further corrected

  15. NOTE: Determination of the recombination correction factor kS for some specific plane-parallel and cylindrical ionization chambers in pulsed photon and electron beams

    NASA Astrophysics Data System (ADS)

    Bruggmoser, G.; Saum, R.; Schmachtenberg, A.; Schmid, F.; Schüle, E.

    2007-01-01

    It has been shown from an evaluation of the inverse reading of the dosemeter (1/M) against the inverse of the polarizing voltage (1/V), obtained with a number of commercially available ionization chambers, using dose per pulse values between 0.16 and 5 mGy, that a linear relationship between the recombination correction factor kS and dose per pulse (DPP) can be found. At dose per pulse values above 1 mGy the method of a general equation with coefficients dependent on the chamber type gives more accurate results than the Boag method. This method was already proposed by Burns and McEwen (1998, Phys. Med. Biol. 43 2033) and avoids comprehensive and time-consuming measurements of Jaffé plots which are a prerequisite for the application of the multi-voltage analysis (MVA) or the two-voltage analysis (TVA). We evaluated and verified the response of ionization chambers on the recombination effect in pulsed accelerator beams for both photons and electrons. Our main conclusions are: (1) The correction factor kS depends only on the DPP and the chamber type. There is no influence of radiation type and energy. (2) For all the chambers investigated there is a linear relationship between kS and DPP up to 5 mGy/pulse, and for two chambers we could show linearity up to 40 mGy/pulse. (3) A general formalism, such as that of Boag, characterizes chambers exclusively by the distance of the electrodes and gives a trend for the correction factor, and therefore (4) a general formalism has to reflect the influence of the chamber construction on the recombination by the introduction of chamber-type dependent coefficients.

  16. Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation, 1945--1947. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-12-01

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the U.S. Department of Energy`s (DOE) Hanford Site near Richland, Washington. The HEDR Project is conducted by Battelle, Pacific Northwest Laboratories (BNW). One of the radionuclides emitted that would affect the radiation dose was iodine-131. This report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947.

  17. WINDOW-WALL INTERFACE CORRECTION FACTORS: THERMAL MODELING OF INTEGRATED FENESTRATION AND OPAQUE ENVELOPE SYSTEMS FOR IMPROVED PREDICTION OF ENERGY USE

    SciTech Connect

    Bhandari, Mahabir S; Ravi, Dr. Srinivasan

    2012-01-01

    The boundary conditions for thermal modeling of fenestration systems assume an adiabatic condition between the fenestration system installed and the opaque envelope system. This theoretical adiabatic boundary condition may not be appropriate owing to heat transfer at the interfaces, particularly for aluminum- framed windows affixed to metal- framed walls. In such scenarios, the heat transfer at the interface may increase the discrepancy between real world thermal indices and laboratory measured or calculated indices based on NFRC Rating System.This paper discusses the development of window-wall Interface Correction Factors (ICF) to improve energy impacts of building envelope systems

  18. Monte Carlo modelling of diode detectors for small field MV photon dosimetry: detector model simplification and the sensitivity of correction factors to source parameterization.

    PubMed

    Cranmer-Sargison, G; Weston, S; Evans, J A; Sidhu, N P; Thwaites, D I

    2012-08-21

    The goal of this work was to examine the use of simplified diode detector models within a recently proposed Monte Carlo (MC) based small field dosimetry formalism and to investigate the influence of electron source parameterization has on MC calculated correction factors. BEAMnrc was used to model Varian 6 MV jaw-collimated square field sizes down to 0.5 cm. The IBA stereotactic field diode (SFD), PTW T60016 (shielded) and PTW T60017 (un-shielded) diodes were modelled in DOSRZnrc and isocentric output ratios (OR(fclin)(detMC)) calculated at depths of d = 1.5, 5.0 and 10.0 cm. Simplified detector models were then tested by evaluating the percent difference in (OR(fclin)(detMC)) between the simplified and complete detector models. The influence of active volume dimension on simulated output ratio and response factor was also investigated. The sensitivity of each MC calculated replacement correction factor (k(fclin,fmsr)(Qclin,Qmsr)), as a function of electron FWHM between 0.100 and 0.150 cm and energy between 5.5 and 6.5 MeV, was investigated for the same set of small field sizes using the simplified detector models. The SFD diode can be approximated simply as a silicon chip in water, the T60016 shielded diode can be modelled as a chip in water plus the entire shielding geometry and the T60017 unshielded diode as a chip in water plus the filter plate located upstream. The detector-specific (k(fclin,fmsr)(Qclin,Qmsr)), required to correct measured output ratios using the SFD, T60016 and T60017 diode detectors are insensitive to incident electron energy between 5.5 and 6.5 MeV and spot size variation between FWHM = 0.100 and 0.150 cm. Three general conclusions come out of this work: (1) detector models can be simplified to produce OR(fclin)(detMC) to within 1.0% of those calculated using the complete geometry, where typically not only the silicon chip, but also any high density components close to the chip, such as scattering plates or shielding material is necessary

  19. Correcting human heart 31P NMR spectra for partial saturation. Evidence that saturation factors for PCr/ATP are homogeneous in normal and disease states

    NASA Astrophysics Data System (ADS)

    Bottomley, Paul A.; Hardy, Christopher J.; Weiss, Robert G.

    Heart PCr/ATP ratios measured from spatially localized 31P NMR spectra can be corrected for partial saturation effects using saturation factors derived from unlocalized chest surface-coil spectra acquired at the heart rate and approximate Ernst angle for phosphor creatine (PCr) and again under fully relaxed conditions during each 31P exam. To validate this approach in studies of normal and disease states where the possibility of heterogeneity in metabolite T1 values between both chest muscle and heart and normal and disease states exists, the properties of saturation factors for metabolite ratios were investigated theoretically under conditions applicable in typical cardiac spectroscopy exams and empirically using data from 82 cardiac 31P exams in six study groups comprising normal controls ( n = 19) and patients with dilated ( n = 20) and hypertrophic ( n = 5) cardiomyopathy, coronary artery disease ( n = 16), heart transplants ( n = 19), and valvular heart disease ( n = 3). When TR ≪ T1,(PCr), with T1(PCr) ⩾ T1(ATP), the saturation factor for PCr/ATP lies in the range 1.5 ± 0.5, regardless of the T1 values. The precise value depends on the ratio of metabolite T1 values rather than their absolute values and is insensitive to modest changes in TR. Published data suggest that the metabolite T1 ratio is the same in heart and muscle. Our empirical data reveal that the saturation factors do not vary significantly with disease state, nor with the relative fractions of muscle and heart contributing to the chest surface-coil spectra. Also, the corrected myocardial PCr/ATP ratios in each normal or disease state bear no correlation with the corresponding saturation factors nor the fraction of muscle in the unlocalized chest spectra. However, application of the saturation correction (mean value, 1.36 ± 0.03 SE) significantly reduced scatter in myocardial PCr/ATP data by 14 ± 11% (SD) ( p ⩽ 0.05). The findings suggest that the relative T1 values of PCr and ATP are

  20. Sensitivity of Satellite-Based Skin Temperature to Different Surface Emissivity and NWP Reanalysis Sources Demonstrated Using a Single-Channel, Viewing-Angle-Corrected Retrieval Algorithm

    NASA Astrophysics Data System (ADS)

    Scarino, B. R.; Minnis, P.; Yost, C. R.; Chee, T.; Palikonda, R.

    2015-12-01

    Single-channel algorithms for satellite thermal-infrared- (TIR-) derived land and sea surface skin temperature (LST and SST) are advantageous in that they can be easily applied to a variety of satellite sensors. They can also accommodate decade-spanning instrument series, particularly for periods when split-window capabilities are not available. However, the benefit of one unified retrieval methodology for all sensors comes at the cost of critical sensitivity to surface emissivity (ɛs) and atmospheric transmittance estimation. It has been demonstrated that as little as 0.01 variance in ɛs can amount to more than a 0.5-K adjustment in retrieved LST values. Atmospheric transmittance requires calculations that employ vertical profiles of temperature and humidity from numerical weather prediction (NWP) models. Selection of a given NWP model can significantly affect LST and SST agreement relative to their respective validation sources. Thus, it is necessary to understand the accuracies of the retrievals for various NWP models to ensure the best LST/SST retrievals. The sensitivities of the single-channel retrievals to surface emittance and NWP profiles are investigated using NASA Langley historic land and ocean clear-sky skin temperature (Ts) values derived from high-resolution 11-μm TIR brightness temperature measured from geostationary satellites (GEOSat) and Advanced Very High Resolution Radiometers (AVHRR). It is shown that mean GEOSat-derived, anisotropy-corrected LST can vary by up to ±0.8 K depending on whether CERES or MODIS ɛs sources are used. Furthermore, the use of either NOAA Global Forecast System (GFS) or NASA Goddard Modern-Era Retrospective Analysis for Research and Applications (MERRA) for the radiative transfer model initial atmospheric state can account for more than 0.5-K variation in mean Ts. The results are compared to measurements from the Surface Radiation Budget Network (SURFRAD), an Atmospheric Radiation Measurement (ARM) Program ground

  1. SiC MOSFET Based Single Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

    SciTech Connect

    Onar, Omer C; Tang, Lixin; Chinthavali, Madhu Sudhan; Campbell, Steven L; Miller , John M.

    2014-01-01

    Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges the utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance due to variable parameters such as battery state-of-charge, coupling factor, and coil misalignment. This paper presents the implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation. The proposed SiC MOSFET based single phase active front end rectifier with PFC resulted in >97% efficiency at 137mm air-gap and >95% efficiency at 160mm air-gap.

  2. Quantifying the influences of various ecological factors on land surface temperature of urban forests.

    PubMed

    Ren, Yin; Deng, Lu-Ying; Zuo, Shu-Di; Song, Xiao-Dong; Liao, Yi-Lan; Xu, Cheng-Dong; Chen, Qi; Hua, Li-Zhong; Li, Zheng-Wei

    2016-09-01

    Identifying factors that influence the land surface temperature (LST) of urban forests can help improve simulations and predictions of spatial patterns of urban cool islands. This requires a quantitative analytical method that combines spatial statistical analysis with multi-source observational data. The purpose of this study was to reveal how human activities and ecological factors jointly influence LST in clustering regions (hot or cool spots) of urban forests. Using Xiamen City, China from 1996 to 2006 as a case study, we explored the interactions between human activities and ecological factors, as well as their influences on urban forest LST. Population density was selected as a proxy for human activity. We integrated multi-source data (forest inventory, digital elevation models (DEM), population, and remote sensing imagery) to develop a database on a unified urban scale. The driving mechanism of urban forest LST was revealed through a combination of multi-source spatial data and spatial statistical analysis of clustering regions. The results showed that the main factors contributing to urban forest LST were dominant tree species and elevation. The interactions between human activity and specific ecological factors linearly or nonlinearly increased LST in urban forests. Strong interactions between elevation and dominant species were generally observed and were prevalent in either hot or cold spots areas in different years. In conclusion, quantitative studies based on spatial statistics and GeogDetector models should be conducted in urban areas to reveal interactions between human activities, ecological factors, and LST.

  3. Quantifying the influences of various ecological factors on land surface temperature of urban forests.

    PubMed

    Ren, Yin; Deng, Lu-Ying; Zuo, Shu-Di; Song, Xiao-Dong; Liao, Yi-Lan; Xu, Cheng-Dong; Chen, Qi; Hua, Li-Zhong; Li, Zheng-Wei

    2016-09-01

    Identifying factors that influence the land surface temperature (LST) of urban forests can help improve simulations and predictions of spatial patterns of urban cool islands. This requires a quantitative analytical method that combines spatial statistical analysis with multi-source observational data. The purpose of this study was to reveal how human activities and ecological factors jointly influence LST in clustering regions (hot or cool spots) of urban forests. Using Xiamen City, China from 1996 to 2006 as a case study, we explored the interactions between human activities and ecological factors, as well as their influences on urban forest LST. Population density was selected as a proxy for human activity. We integrated multi-source data (forest inventory, digital elevation models (DEM), population, and remote sensing imagery) to develop a database on a unified urban scale. The driving mechanism of urban forest LST was revealed through a combination of multi-source spatial data and spatial statistical analysis of clustering regions. The results showed that the main factors contributing to urban forest LST were dominant tree species and elevation. The interactions between human activity and specific ecological factors linearly or nonlinearly increased LST in urban forests. Strong interactions between elevation and dominant species were generally observed and were prevalent in either hot or cold spots areas in different years. In conclusion, quantitative studies based on spatial statistics and GeogDetector models should be conducted in urban areas to reveal interactions between human activities, ecological factors, and LST. PMID:27321883

  4. SU-C-304-06: Determination of Intermediate Correction Factors for Three Dosimeters in Small Composite Photon Fields Used in Robotic Radiosurgery

    SciTech Connect

    Christiansen, E; Belec, J; Vandervoort, E; Muir, B

    2015-06-15

    Purpose: To calculate using Monte-Carlo the intermediate and total correction factors (CFs) for two microchambers and a plastic scintillator for composite fields delivered by the CyberKnife system. Methods: A linac model was created in BEAMnrc by matching percentage depth dose (PDD) curves and output factors (OFs) measured using an A16 microchamber with Monte Carlo calculations performed in egs-chamber to explicitly model detector response. Intermediate CFs were determined for the A16 and A26 microchambers and the W1 plastic scintillator in fourteen different composite fields inside a solid water phantom. Seven of these fields used a 5 mm diameter collimator; the remaining fields employed a 7.5 mm collimator but were otherwise identical to the first seven. Intermediate CFs are reported relative to the respective CF for a 60 mm collimator (800 mm source to detector distance and 100 mm depth in water). Results: For microchambers in composite fields, the intermediate CFs that account for detector density and volume were the largest contributors to total CFs. The total CFs for the A26 were larger than those for the A16, especially for the 5 mm cone (1.227±0.003 to 1.144±0.004 versus 1.142±0.003 to 1.099±0.004), due to the A26’s larger active volume (0.015 cc) relative to the A16 (0.007 cc), despite the A26 using similar wall and electrode material. The W1 total and intermediate CFs are closer to unity, due to its smaller active volume and near water-equivalent composition, however, 3–4% detector volume corrections are required for 5 mm collimator fields. In fields using the 7.5 mm collimator, the correction is nearly eliminated for the W1 except for a non-isocentric field. Conclusion: Large and variable CFs are required for microchambers in small composite fields primarily due to density and volume effects. Corrections are reduced but not eliminated for a plastic scintillator in the same fields.

  5. Computational study of the influence of some systematic factors on the fuel temperature in a very high temperature gas-cooled reactor with prismatic fuel assemblies

    SciTech Connect

    Sedov, A. A.; Frolov, A. A.

    2011-12-15

    The influence of the main systematic factors of overheating (such as nonuniformity of power density and cold leaks of coolant) on the fuel temperatures in a very high temperature gas-cooled reactor NGNP (Next Generation Nuclear Plant) with prismatic fuel blocks is studied. The results of computations show a high sensitivity of the fuel temperatures to systematic factors of overheating. This circumstance indicates the necessity of high-precision three-dimensional modeling of the gas dynamics and heat transfer in the core when designing this type of reactor.

  6. Transcriptome-wide identification of Camellia sinensis WRKY transcription factors in response to temperature stress.

    PubMed

    Wu, Zhi-Jun; Li, Xing-Hui; Liu, Zhi-Wei; Li, Hui; Wang, Yong-Xin; Zhuang, Jing

    2016-02-01

    Tea plant [Camellia sinensis (L.) O. Kuntze] is a leaf-type healthy non-alcoholic beverage crop, which has been widely introduced worldwide. Tea is rich in various secondary metabolites, which are important for human health. However, varied climate and complex geography have posed challenges for tea plant survival. The WRKY gene family in plants is a large transcription factor family that is involved in biological processes related to stress defenses, development, and metabolite synthesis. Therefore, identification and analysis of WRKY family transcription factors in tea plant have a profound significance. In the present study, 50 putative C. sinensis WRKY proteins (CsWRKYs) with complete WRKY domain were identified and divided into three Groups (Group I-III) on the basis of phylogenetic analysis results. The distribution of WRKY family transcription factors among plantae, fungi, and protozoa showed that the number of WRKY genes increased in higher plant, whereas the number of these genes did not correspond to the evolutionary relationships of different species. Structural feature and annotation analysis results showed that CsWRKY proteins contained WRKYGQK/WRKYGKK domains and C2H2/C2HC-type zinc-finger structure: D-X18-R-X1-Y-X2-C-X4-7-C-X23-H motif; CsWRKY proteins may be associated with the biological processes of abiotic and biotic stresses, tissue development, and hormone and secondary metabolite biosynthesis. Temperature stresses suggested that the candidate CsWRKY genes were involved in responses to extreme temperatures. The current study established an extensive overview of the WRKY family transcription factors in tea plant. This study also provided a global survey of CsWRKY transcription factors and a foundation of future functional identification and molecular breeding.

  7. Electron beam quality correction factors for plane-parallel ionization chambers: Monte Carlo calculations using the PENELOPE system.

    PubMed

    Sempau, Josep; Andreo, Pedro; Aldana, Judith; Mazurier, Jocelyne; Salvat, Francesc

    2004-09-21

    Simulations of three plane-parallel ionization chambers have been used to determine directly the chamber- and quality-dependent factors fc,Q, instead of the product (Sw,air p)Q, and kQ,Q0 (or kQ,Q,int) for a broad range of electron beam qualities (4-20 MeV) using divergent monoenergetic beams and phase-space data from two accelerators. An original calculation method has been used which circumvents the weakness of the so far assumed independence between stopping-power ratios and perturbation factors. Very detailed descriptions of the geometry and materials of the chambers have been obtained from the manufacturers, and prepared as input to the PENELOPE 2003 Monte Carlo system using a computer code that includes correlated sampling and particle splitting. Values of the beam quality factors have been determined for the case of an electron reference beam. The calculated values have been compared with those in the IAEA TRS-398 dosimetry protocol and the differences analysed. The results for a NACP-02 chamber show remarkably good agreement with TRS-398 at high electron beam qualities but differ slightly at low energies. Arguments to explain the differences include questioning the undemonstrated assumption that the NACP is a 'perturbation-free' chamber even at very low electron beam energies. Results for Wellhöfer PPC-40 and PPC-05 chambers cannot be compared with data from others for these chambers because no calculations or reliable experimental data exist. It has been found that the results for the PPC-40 are very close to those of a Roos chamber, but the values for the PPC-05 are considerably different from those of a Markus chamber, and rather approach those of a Roos chamber. Results for monoenergetic electrons and accelerator phase-space data have been compared to assess the need for detailed and costly simulations, finding very small differences. This questions the emphasis given in recent years to the use of 'realistic' source data for accurate electron beam

  8. Two-Dimensional Thermal Boundary Layer Corrections for Convective Heat Flux Gauges

    NASA Technical Reports Server (NTRS)

    Kandula, Max; Haddad, George

    2007-01-01

    This work presents a CFD (Computational Fluid Dynamics) study of two-dimensional thermal boundary layer correction factors for convective heat flux gauges mounted in flat plate subjected to a surface temperature discontinuity with variable properties taken into account. A two-equation k - omega turbulence model is considered. Results are obtained for a wide range of Mach numbers (1 to 5), gauge radius ratio, and wall temperature discontinuity. Comparisons are made for correction factors with constant properties and variable properties. It is shown that the variable-property effects on the heat flux correction factors become significant

  9. Long-term global temperature variations under the influence of different cosmophysical factors

    NASA Astrophysics Data System (ADS)

    Biktash, Lilia

    2016-07-01

    We have analyzed different cosmophysical factors which have effect on long-term global temperature variations during solar cycles 20-24. A detailed analysis of total solar irradiance (TSI), the spectral solar ultraviolet emission (UV), space weather and cosmic rays (CRs) have effects on the atmosphere processes. We have shown that increasing of global temperature is likely affected by TSI and UV during solar maxima. During the descending phases of these solar cycles the interplanetary magnetic field and long-lasting solar wind high speed streams occurred frequently and were the primary contributors to minimize of CRs effect on the Earth's atmosphere. In this case global temperature is increased extra as result of increase in the atmosphere's transparency. We show that there are a few effective physical mechanisms of the action of solar activity and space weather on the global temperature. TSI and CRs play essential role in climate change and main part of climate variations can be explained by the mechanism of action TSI and CRs modulated by the solar activity on the state of lower atmosphere and meteorological parameters.

  10. Polysaccharide peptide induces a tumor necrosis factor-α-dependent drop of body temperature in rats.

    PubMed

    Jedrzejewski, Tomasz; Piotrowski, Jakub; Wrotek, Sylwia; Kozak, Wieslaw

    2014-08-01

    Polysaccharide peptide (PSP) extracted from the Coriolus versicolor mushroom is frequently suggested as an adjunct to the chemo- or radiotherapy in cancer patients. It improves quality of the patients' life by decreasing pain, fatigue, loss of appetite, nausea, and vomiting. However, the effect of PSP on body temperature has not thus far been studied, although it is well known that treatment with other polysaccharide adjuvants, such as lipopolysaccharides, may induce fever. The aim of the present study, therefore, was to investigate the influence of PSP on temperature regulation in rats. We report that intraperitoneal injection of PSP provoked a dose-dependent decrease of temperature in male Wistar rats equipped with biotelemetry devices to monitor deep body temperature (Tb). The response was rapid (i.e., with latency of 15-20min), transient (lasting up to 5h post-injection), and accompanied by a significant elevation of the blood tumor necrosis factor-α (TNF-α) level. Pretreatment of the rats with anti-TNF-α antibody prevented the PSP-induced drop in Tb. Based on these data, we conclude that rats may develop an anapyrexia-like response to the injection of peptidopolysaccharide rather than fever, and the response was TNF-α-dependent.

  11. Safety and Efficacy of Growth Factor Concentrate in the Treatment of Nasolabial Fold Correction: Split Face Pilot Study

    PubMed Central

    Sevilla, Gema P; Dhurat, Rachita S; Shetty, Geetanjali; Kadam, Prashant P; Totey, Satish M

    2015-01-01

    Background: Growth factors have long been known as an effective treatment for facial wrinkles. We developed growth factor concentrate (GFC) from the platelets and evaluated their clinical outcome in nasolabial folds. Aims and Objectives: We evaluated safety and efficacy of autologous GFC on patients with nasolabial folds. Materials and Methods: Study was conducted on 80 patients for nasolabial folds in two groups. Group I (20) received bilateral single injection of GFC and group II (60) received single injection of GFC on the right side of the face and platelet-rich plasma (PRP) on the left side of the face. Severity of nasolabial folds was determined at the baseline and 3 months of follow-up visits based on wrinkle severity rating scale (WSRS), Global aesthetic improvement scale (GAIS) and atlas photographic grading at rest and at full smile. Objective clinical assessment and subjective satisfaction scale was determined for overall improvement at the end of the study. Results: In group I, 2 subjects showed improvement after GFC treatment with the score of 3.1–4 (76–100%), 3 subjects with the score of 2.1–3 (51–75%), 14 with the score of 1.1–2 (26–50%) and 1 subject with the score of 0–1 (<25%) at the end of study. In group II, 51 subjects were evaluated at the end of study where, 34 (66%) showed superior improvements after GFC, 6 (11%) patients showed similar improvement on both side of the face, 10 (19.6%) patients showed no noticeable improvement on the either side of the face and only 1 patient (1.96%) showed superior improvement for PRP at the end of the study. Overall improvement score analysis showed that GFC was significantly superior to PRP (P < 0.001). Conclusion: Present study is a strong evidence to support the use of GFC for nasolabial folds. The results showed that the single application of GFC is highly effective and safe. PMID:26538718

  12. Trends in 1970-2010 summertime coastal California air temperatures:how HCN-corrections to COOP-data eliminated coastal-cooling

    NASA Astrophysics Data System (ADS)

    Bornstein, R. D.; Ghebreegziabher, A. T.; Lebassi, B.; González, J. E.

    2011-12-01

    The analysis of California COOP-site monthly-averaged summer Tmax-trends (1970-2005) by Lebassi et al. (2009, in J. of Climate) has been extended by: (a) lengthening the period to 2010, (b) trend-comparisons with newly released HCN data, and (c) calculation of trends in annual Tmax-values. HCN data sets are NCDC-homogenized subsets of the "most trusted" COOP sites; they include 12 (of the 52 COOP sites) in the San Francisco Bay Area and four (of 28) in the Southern California Air Basin (SoCAB). COOP data used as HCN1 data were adjusted by NCDC for the following biases: (a) time-of-observations, (b) spatial inhomogeneity, (c) missing values, (d) changes in thermometer type, and (e) urban warming, while HCN2 data do not include the last two corrections. Comparison of the 35- and 40-year COOP monthly-averaged Tmax-trends at the 16 HCN sites showed a high correlation (0.96). It also showed, however, that as the six inland warming-sites (COOP sites also HCN sites) of Lebassi et al. are now generally warming a slightly lower rate than five years ago, the seven comparable coastal-cooling sites are thus now generally cooling at a slightly lower rate. Coastal-cooling was shown by Lebassi et al. as a "reverse-reaction" to regional warming in inland areas, which triggers coastal sea breezes, and which thus increased cooling onshore flows. Comparison of HCN1 and COOP 35-year Tmax-trends shows little correlation (0.15), as the HCN1-corrections changed six of the seven COOP cooling-sites into HCN1 warming-sites. Only the site with largest original COOP cooling also showed HCN1 cooling. Similar comparisons between the COOP and HCN2 sites showed that HCN2-corrections changed fewer (only four) cooling-sites to warming (and with lower warming-rates); a low correlation (0.44) thus existed between trend-values. As many climate-change impacts (e.g., brown outs, heat stress, ozone peaks) depend on extreme Tmax-values, and not just averaged-monthly Tmax-values, the SoCAB distribution of

  13. Extremely high Q-factor mechanical modes in quartz bulk acoustic wave resonators at millikelvin temperature

    SciTech Connect

    Goryachev, M.; Creedon, D. L.; Ivanov, E. N.; Tobar, M. E.; Galliou, S.; Bourquin, R.

    2014-12-04

    We demonstrate that Bulk Acoustic Wave (BAW) quartz resonator cooled down to millikelvin temperatures are excellent building blocks for hybrid quantum systems with extremely long coherence times. Two overtones of the longitudinal mode at frequencies of 15.6 and 65.4 MHz demonstrate a maximum f.Q product of 7.8×10{sup 16} Hz. With this result, the Q-factor in such devices near the quantum ground state can be four orders of magnitude better than previously attained in other mechanical systems. Tested quartz resonators possess the ultra low acoustic losses crucial for electromagnetic cooling to the phonon ground state.

  14. Small fields output factors measurements and correction factors determination for several detectors for a CyberKnife{sup Registered-Sign} and linear accelerators equipped with microMLC and circular cones

    SciTech Connect

    Bassinet, C.; Huet, C.; Derreumaux, S.; Baumann, M.; Trompier, F.; Roch, P.; Clairand, I.; Brunet, G.; Gaudaire-Josset, S.; Chea, M.; Boisserie, G.

    2013-07-15

    Purpose: The use of small photon fields is now an established practice in stereotactic radiosurgery and radiotherapy. However, due to a lack of lateral electron equilibrium and high dose gradients, it is difficult to accurately measure the dosimetric quantities required for the commissioning of such systems. Moreover, there is still no metrological dosimetric reference for this kind of beam today. In this context, the first objective of this work was to determine and to compare small fields output factors (OF) measured with different types of active detectors and passive dosimeters for three types of facilities: a CyberKnife{sup Registered-Sign} system, a dedicated medical linear accelerator (Novalis) equipped with m3 microMLC and circular cones, and an adaptive medical linear accelerator (Clinac 2100) equipped with an additional m3 microMLC. The second one was to determine the k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}} correction factors introduced in a recently proposed small field dosimetry formalism for different active detectors.Methods: Small field sizes were defined either by microMLC down to 6 Multiplication-Sign 6 mm{sup 2} or by circular cones down to 4 mm in diameter. OF measurements were performed with several commercially available active detectors dedicated to measurements in small fields (high resolution diodes: IBA SFD, Sun Nuclear EDGE, PTW 60016, PTW 60017; ionizing chambers: PTW 31014 PinPoint chamber, PTW 31018 microLion liquid chamber, and PTW 60003 natural diamond). Two types of passive dosimeters were used: LiF microcubes and EBT2 radiochromic films.Results: Significant differences between the results obtained by several dosimetric systems were observed, particularly for the smallest field size for which the difference in the measured OF reaches more than 20%. For passive dosimeters, an excellent agreement was observed (better than 2%) between EBT2 and LiF microcubes

  15. Exposure levels due to WLAN devices in indoor environments corrected by a time-amplitude factor of distribution of the quasi-stochastic signals.

    PubMed

    Miclaus, Simona; Bechet, Paul; Stratakis, Dimitrios

    2014-12-01

    With the development of radiofrequency technology, radiating quasi-stochastic signals like the wireless local area networks (WLAN), a proper procedure of exposure level assessment is needed. No standardised procedure exists at the moment. While channel power measurement proved to overestimate the field strength, weighting techniques were proposed. The paper compares the exposure levels determined by three different procedures, two of them correcting the field level by weighting. Twenty-three experimental cases of WLAN traffic load are analysed in an indoor environment in controlled conditions. The results show the differences obtained when the duty cycle (DC) method is applied comparatively with the application of weighting based on an amplitude-time correction. Significant exposure level reductions of 52.6-79.2 % from the field determined by frequency domain method and of 36.5-72.8 % from the field determined by the DC weighting method were obtained by time-amplitude method. Specificities of weighting factors probability density functions were investigated and regression analysis was applied for a detailed characterisation of this procedure. PMID:24591729

  16. Evaluation of Wall Correction Factor of INER's Air-Kerma Primary Standard Chamber and Dose Variation by Source Displacement for HDR 192Ir Brachytherapy

    PubMed Central

    Lee, J. H.; Wang, J. N.; Huang, T. T.; Su, S. H.; Chang, B. J.; Su, C. H.; Hsu, S. M.

    2013-01-01

    The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR) 192Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan). The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the 192Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA) and the National Physical Laboratory (NPL, UK) for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR 192Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR 192Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity. PMID:24222907

  17. Evaluation of wall correction factor of INER's air-kerma primary standard chamber and dose variation by source displacement for HDR ¹⁹²Ir brachytherapy.

    PubMed

    Lee, J H; Wang, J N; Huang, T T; Su, S H; Chang, B J; Su, C H; Hsu, S M

    2013-01-01

    The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR) ¹⁹²Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan). The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the ¹⁹²Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA) and the National Physical Laboratory (NPL, UK) for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR ¹⁹²Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR ¹⁹²Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity. PMID:24222907

  18. WE-E-18A-05: Bremsstrahlung of Laser-Plasma Interaction at KeV Temperature: Forward Dose and Attenuation Factors

    SciTech Connect

    Saez-Beltran, M; Fernandez Gonzalez, F

    2014-06-15

    Purpose: To obtain an analytical empirical formula for the photon dose source term in forward direction from bremsstrahlung generated from laser-plasma accelerated electron beams in aluminum solid targets, with electron-plasma temperatures in the 10–100 keV energy range, and to calculate transmission factors for iron, aluminum, methacrylate, lead and concrete and air, materials most commonly found in vacuum chamber labs. Methods: Bremsstrahlung fluence is calculated from the convolution of thin-target bremsstrahlung spectrum for monoenergetic electrons and the relativistic Maxwell-Juettner energy distribution for the electron-plasma. Unattenuatted dose in tissue is calculated by integrating the photon spectrum with the mass-energy absorption coefficient. For the attenuated dose, energy dependent absorption coefficient, build-up factors and finite shielding correction factors were also taken into account. For the source term we use a modified formula from Hayashi et al., and we fitted the proportionality constant from experiments with the aid of the previously calculated transmission factors. Results: The forward dose has a quadratic dependence on electron-plasma temperature: 1 joule of effective laser energy transferred to the electrons at 1 m in vacuum yields 0,72 Sv per MeV squared of electron-plasma temperature. Air strongly filters the softer part of the photon spectrum and reduce the dose to one tenth in the first centimeter. Exponential higher energy tail of maxwellian spectrum contributes mainly to the transmitted dose. Conclusion: A simple formula for forward photon dose from keV range temperature plasma is obtained, similar to those found in kilovoltage x-rays but with higher dose per dissipated electron energy, due to thin target and absence of filtration.

  19. Electroweak Corrections

    NASA Astrophysics Data System (ADS)

    Barbieri, Riccardo

    2016-10-01

    The test of the electroweak corrections has played a major role in providing evidence for the gauge and the Higgs sectors of the Standard Model. At the same time the consideration of the electroweak corrections has given significant indirect information on the masses of the top and the Higgs boson before their discoveries and important orientation/constraints on the searches for new physics, still highly valuable in the present situation. The progression of these contributions is reviewed.

  20. Decline in insulin-like growth factor I levels after clomiphene citrate does not correct hyperandrogenemia in polycystic ovary syndrome.

    PubMed

    Fiad, T M; Smith, T P; Cunningham, S K; McKenna, T J

    1998-07-01

    It is widely accepted that the action of clomiphene citrate (CC) is mediated through its antiestrogenic properties on the hypothalamic-pituitary axis. Although insulin-like growth factor I (IGF-I) enhances the thecal cell response to LH, and estrogen treatment is associated with a reduction in IGF-I levels, CC is known to decrease circulatory IGF-I levels in polycystic ovary syndrome (PCOS) patients. The impact of lowering IGF-I levels on androgen levels in PCOS is unknown. This study was designed to examine the impact of CC treatment on the interrelationships of IGF-I, androgens, and estrogens in normal subjects and patients with PCOS. IGF-I, gonadotropin, androgen, estrogen, and sex hormone-binding globulin levels were measured in 8 PCOS patients and 10 normal subjects before and after treatment with the antiestrogen CC. Studies were performed in the early follicular phase, days 4-6 of the menstrual cycle in normal subjects. In normal subjects, CC treatment led to a significant increase in estradiol (84 +/- 10 to 234 +/- 62 pmol/L, untreated and CC treated; P < 0.05) and estrone (125 +/- 14 to 257 +/- 29 pmol/L; P < 0.05) levels with a significant lowering of IGF-I levels (297 +/- 25 to 230 +/- 17 micrograms/L; P < 0.05). Similarly, in PCOS patients a significant increase in estradiol (110 +/- 11 to 245 +/- 58 pmol/L; P < 0.05) and estrone (301 +/- 32 to 401 +/- 90 pmol/L; P < 0.05) levels and a significant lowering of IGF-I levels (330 +/- 43 to 214 +/- 27 micrograms/L; P < 0.05) were observed after CC treatment. However, no significant correlation was observed between changes in IGF-I and changes in estradiol in either group. Compared to pretreatment levels, no significant changes in the following parameters were observed after 5 days of CC treatment in either study group: testosterone, testosterone/sex hormone-binding globulin ratio, and androstenedione. The relationship among CC treatment, gonadotropin, estrogen, and IGF-I levels is complex. Changes in blood

  1. Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam.

    PubMed

    Pham, C H; Vu, C C; Sommer, S G; Bruun, S

    2014-07-01

    This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank.

  2. Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam.

    PubMed

    Pham, C H; Vu, C C; Sommer, S G; Bruun, S

    2014-07-01

    This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank. PMID:25050049

  3. Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam

    PubMed Central

    Pham, C. H.; Vu, C. C.; Sommer, S. G.; Bruun, S.

    2014-01-01

    This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank. PMID:25050049

  4. Characterization of radiation beams used to determinate the correction factor for a CyberKnife® unit reference field using ionization chambers

    NASA Astrophysics Data System (ADS)

    Aragón-Martínez, Nestor; Gómez-Muñoz, Arnulfo; Massillon-JL, Guerda

    2014-11-01

    This paper aimed to characterize a 6 MV x-ray beam from a Varian® iX linear accelerator in order to obtain the correction factors needed by the IAEA/AAPM new formalism1. The experiments were performed in a liquid water phantom under different irradiation conditions: a) Calibration of the reference field of 10 cm × 10 cm at 90 cm SSD and 10 cm depth was carried out according to the TRS-398 protocol using three ionization chambers (IC) calibrated in different reference laboratory and b) Measurement of the absorbed dose rate at 70 cm SSD and 10 cm depth in a 10 cm × 10 cm and 5.4 cm × 5.4 cm fields was obtained in order to simulate the CyberKnife® conditions where maximum distance between the source and the detector is equal to 80 cm and the maximum field size is 6 cm diameter. Depending where the IC was calibrated, differences between 0.16% and 2.24% in the absorbed dose rate measured in the 10 cm × 10 cm field at 90 cm SSD were observed, while for the measurements at 70 cm SSD, differences between 1.27% and 3.88% were obtained. For the 5.4 cm × 5.4 cm field, the absorbed dose measured with the three ICs varies between 1.37% and 3.52%. The increase in the difference on the absorbed dose when decreasing the SSD could possibly be associated to scattering radiation generated from the collimators and/or the energy dependence of the ionization chambers to low-energy radiation. The results presented in this work suggest the importance of simulating the CyberKnife® conditions using other linear accelerator for obtaining the correction factors as proposed by the IAEA/AAPM new formalism in order to measure the absorbed dose with acceptable accuracy.

  5. Characterization of radiation beams used to determinate the correction factor for a CyberKnife® unit reference field using ionization chambers

    SciTech Connect

    Aragón-Martínez, Nestor Massillon-JL, Guerda; Gómez-Muñoz, Arnulfo

    2014-11-07

    This paper aimed to characterize a 6 MV x-ray beam from a Varian® iX linear accelerator in order to obtain the correction factors needed by the IAEA/AAPM new formalism{sup 1}. The experiments were performed in a liquid water phantom under different irradiation conditions: a) Calibration of the reference field of 10 cm × 10 cm at 90 cm SSD and 10 cm depth was carried out according to the TRS-398 protocol using three ionization chambers (IC) calibrated in different reference laboratory and b) Measurement of the absorbed dose rate at 70 cm SSD and 10 cm depth in a 10 cm × 10 cm and 5.4 cm × 5.4 cm fields was obtained in order to simulate the CyberKnife® conditions where maximum distance between the source and the detector is equal to 80 cm and the maximum field size is 6 cm diameter. Depending where the IC was calibrated, differences between 0.16% and 2.24% in the absorbed dose rate measured in the 10 cm × 10 cm field at 90 cm SSD were observed, while for the measurements at 70 cm SSD, differences between 1.27% and 3.88% were obtained. For the 5.4 cm × 5.4 cm field, the absorbed dose measured with the three ICs varies between 1.37% and 3.52%. The increase in the difference on the absorbed dose when decreasing the SSD could possibly be associated to scattering radiation generated from the collimators and/or the energy dependence of the ionization chambers to low-energy radiation. The results presented in this work suggest the importance of simulating the CyberKnife® conditions using other linear accelerator for obtaining the correction factors as proposed by the IAEA/AAPM new formalism in order to measure the absorbed dose with acceptable accuracy.

  6. Monte Carlo computed machine-specific correction factors for reference dosimetry of TomoTherapy static beam for several ion chambers

    SciTech Connect

    Sterpin, E.; Mackie, T. R.; Vynckier, S.

    2012-07-15

    Purpose: To determine k{sub Q{sub m{sub s{sub r,Q{sub o}{sup f{sub m}{sub s}{sub r},f{sub o}}}}}} correction factors for machine-specific reference (msr) conditions by Monte Carlo (MC) simulations for reference dosimetry of TomoTherapy static beams for ion chambers Exradin A1SL, A12; PTW 30006, 31010 Semiflex, 31014 PinPoint, 31018 microLion; NE 2571. Methods: For the calibration of TomoTherapy units, reference conditions specified in current codes of practice like IAEA/TRS-398 and AAPM/TG-51 cannot be realized. To cope with this issue, Alfonso et al. [Med. Phys. 35, 5179-5186 (2008)] described a new formalism introducing msr factors k{sub Q{sub m{sub s{sub r,Q{sub o}{sup f{sub m}{sub s}{sub r},f{sub o}}}}}} for reference dosimetry, applicable to static TomoTherapy beams. In this study, those factors were computed directly using MC simulations for Q{sub 0} corresponding to a simplified {sup 60}Co beam in TRS-398 reference conditions (at 10 cm depth). The msr conditions were a 10 Multiplication-Sign 5 cm{sup 2} TomoTherapy beam, source-surface distance of 85 cm and 10 cm depth. The chambers were modeled according to technical drawings using the egs++ package and the MC simulations were run with the egs{sub c}hamber user code. Phase-space files used as the source input were produced using PENELOPE after simulation of a simplified {sup 60}Co beam and the TomoTherapy treatment head modeled according to technical drawings. Correlated sampling, intermediate phase-space storage, and photon cross-section enhancement variance reduction techniques were used. The simulations were stopped when the combined standard uncertainty was below 0.2%. Results: Computed k{sub Q{sub m{sub s{sub r,Q{sub o}{sup f{sub m}{sub s}{sub r},f{sub o}}}}}} values were all close to one, in a range from 0.991 for the PinPoint chamber to 1.000 for the Exradin A12 with a statistical uncertainty below 0.2%. Considering a beam quality Q defined as the TPR{sub 20,10} for a 6 MV Elekta photon beam (0

  7. A practical methodology to measure unbiased gas chromatographic retention factor vs. temperature relationships.

    PubMed

    Peng, Baijie; Kuo, Mei-Yi; Yang, Panhia; Hewitt, Joshua T; Boswell, Paul G

    2014-12-29

    Compound identification continues to be a major challenge. Gas chromatography-mass spectrometry (GC-MS) is a primary tool used for this purpose, but the GC retention information it provides is underutilized because existing retention databases are experimentally restrictive and unreliable. A methodology called "retention projection" has the potential to overcome these limitations, but it requires the retention factor (k) vs. T relationship of a compound to calculate its retention time. Direct methods of measuring k vs. T relationships from a series of isothermal runs are tedious and time-consuming. Instead, a series of temperature programs can be used to quickly measure the k vs. T relationships, but they are generally not as accurate when measured this way because they are strongly biased by non-ideal behavior of the GC system in each of the runs. In this work, we overcome that problem by using the retention times of 25 n-alkanes to back-calculate the effective temperature profile and hold-up time vs. T profiles produced in each of the six temperature programs. When the profiles were measured this way and taken into account, the k vs. T relationships measured from each of two different GC-MS instruments were nearly as accurate as the ones measured isothermally, showing less than two-fold more error. Furthermore, temperature-programmed retention times calculated in five other laboratories from the new k vs. T relationships had the same distribution of error as when they were calculated from k vs. T relationships measured isothermally. Free software was developed to make the methodology easy to use. The new methodology potentially provides a relatively fast and easy way to measure unbiased k vs. T relationships.

  8. Mechanism and Influencing Factors of Iron Nuggets Forming in Rotary Hearth Furnace Process at Lower Temperature

    NASA Astrophysics Data System (ADS)

    Han, Hongliang; Duan, Dongping; Chen, Siming; Yuan, Peng

    2015-10-01

    In order to improve the efficiency of slag and iron separation, a new idea of "the separation of slag (solid state) and iron (molten state) in rotary hearth furnace process at lower temperature" is put forward. In this paper, the forming process of iron nuggets has been investigated. Based on those results, the forming mechanisms and influencing factors of iron nugget at low temperature are discussed experimentally using an electric resistance furnace simulating a rotary hearth furnace process. Results show that the reduction of iron ore, carburization of reduced iron, and the composition and quantity of slag are very important for producing iron nuggets at lower temperature. Reduction reaction of carbon-containing pellets is mainly at 1273 K and 1473 K (1000 °C and 1200 °C). When the temperature is above 1473 K (1200 °C), the metallization rate of carbon-containing pellets exceeds 93 pct, and the reduction reaction is substantially complete. Direct carburization is the main method for carburization of reduced iron. This reaction occurs above 1273 K (1000 °C), with carburization degree increasing greatly at 1473 K and 1573 K (1200 °C and 1300 °C) after particular holding times. Besides, to achieve the "slag (solid state) and iron (molten state) separation," the melting point of the slag phase should be increased. Slag (solid state) and iron (molten state) separation can be achieved below 1573 K (1300 °C), and when the holding time is 20 minutes, C/O is 0.7, basicity is less than 0.5 and a Na2CO3 level of 3 pct, the recovery rate of iron can reach 90 pct, with a proportion of iron nuggets more than 3.15 mm of nearly 90 pct. This study can provide theoretical and technical basis for iron nugget production.

  9. Molecular Factors and Biochemical Pathways Induced by Febrile Temperature in Intraerythrocytic Plasmodium falciparum Parasites▿ †

    PubMed Central

    Oakley, Miranda S. M.; Kumar, Sanjai; Anantharaman, Vivek; Zheng, Hong; Mahajan, Babita; Haynes, J. David; Moch, J. Kathleen; Fairhurst, Rick; McCutchan, Thomas F.; Aravind, L.

    2007-01-01

    Intermittent episodes of febrile illness are the most benign and recognized symptom of infection with malaria parasites, although the effects on parasite survival and virulence remain unclear. In this study, we identified the molecular factors altered in response to febrile temperature by measuring differential expression levels of individual genes using high-density oligonucleotide microarray technology and by performing biological assays in asexual-stage Plasmodium falciparum parasite cultures incubated at 37°C and 41°C (an elevated temperature that is equivalent to malaria-induced febrile illness in the host). Elevated temperature had a profound influence on expression of individual genes; 336 of approximately 5,300 genes (6.3% of the genome) had altered expression profiles. Of these, 163 genes (49%) were upregulated by twofold or greater, and 173 genes (51%) were downregulated by twofold or greater. In-depth sensitive sequence profile analysis revealed that febrile temperature-induced responses caused significant alterations in the major parasite biologic networks and pathways and that these changes are well coordinated and intricately linked. One of the most notable transcriptional changes occurs in genes encoding proteins containing the predicted Pexel motifs that are exported into the host cytoplasm or inserted into the host cell membrane and are likely to be associated with erythrocyte remodeling and parasite sequestration functions. Using our sensitive computational analysis, we were also able to assign biochemical or biologic functional predictions for at least 100 distinct genes previously annotated as “hypothetical.” We find that cultivation of P. falciparum parasites at 41°C leads to parasite death in a time-dependent manner. The presence of the “crisis forms” and the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling-positive parasites following heat treatment strongly support the notion that an apoptosis-like cell

  10. Environmental factors affecting the low temperature isomerization of homohopanes in acidic peat deposits, central China

    NASA Astrophysics Data System (ADS)

    Huang, Xianyu; Meyers, Philip A.; Xue, Jiantao; Gong, Linfeng; Wang, Xinxin; Xie, Shucheng

    2015-04-01

    Progressively more evidence reveals the abundant occurrence of the C31 homohopane with a 17α, 21β-configuration (C31 αβ) in immature peats. This compound is commonly considered to be an indicator of thermal maturity in petroleum source rocks, but in peats it has also been interpreted to reflect the oxidation and subsequent decarboxylation reactions of bacteriohopanepolyols with microbially mediated epimerization at C-17 that is catalyzed by the acidic peat conditions. To learn more about the environmental factors that affect the low-temperature isomerization of homohopanes, we investigated the distribution patterns of homohopanes in a well-studied peat core from the Dajiuhu peatland, central China, together with data from modern surface peat samples from Dajiuhu and three other locations. From comparison with paleotemperature and paleohydrologic records in the peat core, we hypothesize that the ratio of C31 αβ hopane relative to the ββ isomer (C31 αβ/ββ) is mainly influenced on a centennial to millennial timescale by ambient temperature with a secondary effect from redox conditions that are defined by peatland water levels. The surface peat samples revealed that relatively high C31 αβ/ββ values occurred under pH < 6. These results suggest that pH is indeed an important factor in the low-temperature isomerization of C31 homohopanes, although the magnitude of the pH effect may be less than those of ambient temperature and redox conditions. In both surface peat and peat horizons from the Dajiuhu peatland, the amount of the C31 αβ compound with R configuration relative to that with S configuration (C31 R/S) varied closely with C31 αβ/ββ, suggesting that the epimerization at both C-17 and C-22 may happen synchronously and at similar rates. This study reveals that the isomerization of homohopanes has the potential to reflect paleoenvironmental changes in acidic peat deposits. In addition, acidic peat samples investigated in this and previous studies

  11. Maximizing the spatial representativeness of NO2 monitoring data using a combination of local wind-based sectoral division and seasonal and diurnal correction factors.

    PubMed

    Donnelly, Aoife; Naughton, Owen; Misstear, Bruce; Broderick, Brian

    2016-10-14

    This article describes a new methodology for increasing the spatial representativeness of individual monitoring sites. Air pollution levels at a given point are influenced by emission sources in the immediate vicinity. Since emission sources are rarely uniformly distributed around a site, concentration levels will inevitably be most affected by the sources in the prevailing upwind direction. The methodology provides a means of capturing this effect and providing additional information regarding source/pollution relationships. The methodology allows for the division of the air quality data from a given monitoring site into a number of sectors or wedges based on wind direction and estimation of annual mean values for each sector, thus optimising the information that can be obtained from a single monitoring station. The method corrects for short-term data, diurnal and seasonal variations in concentrations (which can produce uneven weighting of data within each sector) and uneven frequency of wind directions. Significant improvements in correlations between the air quality data and the spatial air quality indicators were obtained after application of the correction factors. This suggests the application of these techniques would be of significant benefit in land-use regression modelling studies. Furthermore, the method was found to be very useful for estimating long-term mean values and wind direction sector values using only short-term monitoring data. The methods presented in this article can result in cost savings through minimising the number of monitoring sites required for air quality studies while also capturing a greater degree of variability in spatial characteristics. In this way, more reliable, but also more expensive monitoring techniques can be used in preference to a higher number of low-cost but less reliable techniques. The methods described in this article have applications in local air quality management, source receptor analysis, land-use regression

  12. Maximizing the spatial representativeness of NO2 monitoring data using a combination of local wind-based sectoral division and seasonal and diurnal correction factors.

    PubMed

    Donnelly, Aoife; Naughton, Owen; Misstear, Bruce; Broderick, Brian

    2016-10-14

    This article describes a new methodology for increasing the spatial representativeness of individual monitoring sites. Air pollution levels at a given point are influenced by emission sources in the immediate vicinity. Since emission sources are rarely uniformly distributed around a site, concentration levels will inevitably be most affected by the sources in the prevailing upwind direction. The methodology provides a means of capturing this effect and providing additional information regarding source/pollution relationships. The methodology allows for the division of the air quality data from a given monitoring site into a number of sectors or wedges based on wind direction and estimation of annual mean values for each sector, thus optimising the information that can be obtained from a single monitoring station. The method corrects for short-term data, diurnal and seasonal variations in concentrations (which can produce uneven weighting of data within each sector) and uneven frequency of wind directions. Significant improvements in correlations between the air quality data and the spatial air quality indicators were obtained after application of the correction factors. This suggests the application of these techniques would be of significant benefit in land-use regression modelling studies. Furthermore, the method was found to be very useful for estimating long-term mean values and wind direction sector values using only short-term monitoring data. The methods presented in this article can result in cost savings through minimising the number of monitoring sites required for air quality studies while also capturing a greater degree of variability in spatial characteristics. In this way, more reliable, but also more expensive monitoring techniques can be used in preference to a higher number of low-cost but less reliable techniques. The methods described in this article have applications in local air quality management, source receptor analysis, land-use regression

  13. Quantitative Analysis of the Head Scatter and Jaw Transmission Correction Factor for Commissioning of Enhanced Dynamic Wedge Fields Using a MapCHECK 2 Diode Array

    NASA Astrophysics Data System (ADS)

    Dickerson, Edward C.

    Quality assurance in radiation oncology treatment planning requires independent verification of dose to be delivered to a patient through "second check" calculations for simple plans as well as planar dose fluence measurements for more complex treatments, such as intensity modulated radiation treatments (IMRT). Discrepancies between treatment planning system (TPS) and second check calculations created a need for treatment plan verification using a two dimensional diode array for Enhanced Dynamic Wedge (EDW) fields. While these measurements met clinical standards for treatment, they revealed room for improvement in the EDW model. The purpose of this study is to analyze the head scatter and jaw transmission effects of the moving jaw in EDW fields by measuring dose profiles with a two dimensional diode array in order to minimize differences between the manufacturer provided fluence table (Golden Segmented Treatment Table) and actual machine output. The jaw transmission effect reduces the dose gradient in the wedge direction due to transmission photons adding dose to the heel region of the field. The head scatter effect also reduces the gradient in the dose profile due to decreased accelerator output at increasingly smaller field sizes caused by the moving jaw. The field size continuously decreases with jaw motion, and thus the toe region of the wedge receives less dose than anticipated due to less head scatter contribution for small field sizes. The Golden Segmented Treatment Table (GSTT) does not take these factors into account since they are specific to each individual machine. Thus, these factors need to be accounted for in the TPS to accurately model the gradient of the wedge. The TPS used in this clinic uses one correction factor (transmission factor) to account for both effects since both factors reduce the dose gradient of the wedge. Dose profile measurements were made for 5x5 cm2, 10x10 cm2, and 20x20 cm2 field sizes with open fields and 10°, 15°, 20°, 25

  14. Jitter Correction

    NASA Technical Reports Server (NTRS)

    Waegell, Mordecai J.; Palacios, David M.

    2011-01-01

    Jitter_Correct.m is a MATLAB function that automatically measures and corrects inter-frame jitter in an image sequence to a user-specified precision. In addition, the algorithm dynamically adjusts the image sample size to increase the accuracy of the measurement. The Jitter_Correct.m function takes an image sequence with unknown frame-to-frame jitter and computes the translations of each frame (column and row, in pixels) relative to a chosen reference frame with sub-pixel accuracy. The translations are measured using a Cross Correlation Fourier transformation method in which the relative phase of the two transformed images is fit to a plane. The measured translations are then used to correct the inter-frame jitter of the image sequence. The function also dynamically expands the image sample size over which the cross-correlation is measured to increase the accuracy of the measurement. This increases the robustness of the measurement to variable magnitudes of inter-frame jitter

  15. [Accidental hypothermia. Risk factors in 29 patients with body temperature of 30 degrees C and below].

    PubMed

    Pillgram-Larsen, J; Svennevig, J L; Abdelnoor, M; Fjeld, N B; Semb, G; Osterud, A; Skulberg, A

    1991-01-20

    29 patients with a body temperature below 30 degrees C (mean 26.4 degrees C) were treated during the period 1982-88, both years inclusive. Eight patients were severely hypotensive (systolic blood pressure less than 60 mm Hg) and two had ventricular fibrillation on admission. Bradycardia (less than 60 beats per minute) was noted in ten patients. 12 patients were rewarmed by surface warming, 17 by extracorporeal circulation with femoral cannulation. 22 patients (76%) were discharged alive. Age, sex, body temperature, method and rate of rewarming, serum electrolytes, acidosis and the use of blood components did not influence the outcome. Renal failure was the only complication associated with a fatal outcome. Severe hypotension on admission tended to increase mortality, but logistic regression analysis identified the mode of cooling as the only independent risk factor for death. A patient cooled indoors had an odd risk of 10.6 of hospital mortality compared to one found outdoors. For the sake of convenience, in hospitals with the available resources rewarming by extracorporeal circulation may be used in patients with circulatory arrest, since this is the easiest way to control and support failing circulation. In all other cases carefully monitored surface rewarming should be used as this necessitates less use of hospital resources and produces equally good results. PMID:1998174

  16. RNA thermometer controls temperature-dependent virulence factor expression in Vibrio cholerae.

    PubMed

    Weber, Gregor G; Kortmann, Jens; Narberhaus, Franz; Klose, Karl E

    2014-09-30

    Vibrio cholerae is the bacterium that causes the diarrheal disease cholera. The bacteria experience a temperature shift as V. cholerae transition from contaminated water at lower temperatures into the 37 °C human intestine. Within the intestine, V. cholerae express cholera toxin (CT) and toxin-coregulated pilus (TCP), two main virulence factors required for disease. CT and TCP expression is controlled by the transcriptional activator protein ToxT. We identified an RNA thermometer motif in the 5' UTR of toxT, with a fourU anti-Shine-Dalgarno (SD) element that base pairs with the SD sequence to regulate ribosome access to the mRNA. RNA probing experiments demonstrated that the fourU element allowed access to the SD sequence at 37 °C but not at 20 °C. Moreover, mutations within the fourU element (U5C, U7C) that strengthened base-pairing between the anti-SD and SD sequences prevented access to the SD sequence even at 37 °C. Translation of ToxT-FLAG from the native toxT UTR was enhanced at 37 °C, compared with 25 °C in both Escherichia coli and V. cholerae. In contrast, the U5C, U7C UTR prevented translation of ToxT-FLAG even at 37 °C. V. cholerae mutants containing the U5C, U7C UTR variant were unable to colonize the infant mouse small intestine. Our results reveal a previously unknown regulatory mechanism consisting of an RNA thermometer that controls temperature-dependent translation of toxT, facilitating V. cholerae virulence at a relevant environmental condition found in the human intestine.

  17. Adsorbate migration effects on continuous and discontinuous temperature-dependent transitions in the quality factors of graphene nanoresonators.

    PubMed

    Jiang, Jin-Wu; Wang, Bing-Shen; Park, Harold S; Rabczuk, Timon

    2014-01-17

    We perform classical molecular dynamics simulation to investigate the mechanisms underpinning the unresolved, experimentally observed temperature-dependent scaling transition in the quality factors of graphene nanomechanical resonators (GNMRs). Our simulations reveal that the mechanism underlying this temperature scaling phenomenon is the out-of-plane migration of adsorbates on GNMRs. Specifically, the migrating adsorbate undergoes frequent collisions with the GNMR, which strongly influences the resulting mechanical oscillation, and thus the quality factors. We also predict a discontinuous transition in the quality factor at a lower critical temperature, which results from the in-plane migration of the adsorbate. Overall, our work clearly demonstrates the strong effect of adsorbate migration on the quality factors of GNMRs. PMID:24334407

  18. JAIBA, a class-II HD-ZIP transcription factor involved in the regulation of meristematic activity, and important for correct gynoecium and fruit development in Arabidopsis.

    PubMed

    Zúñiga-Mayo, Victor M; Marsch-Martínez, Nayelli; de Folter, Stefan

    2012-07-01

    The gynoecium is one of the most complex organs of a plant. After fertilization, it becomes a fruit, which has two important functions: to protect the seeds while they develop and to disperse them at maturity. The development and patterning of the gynoecium and later fruit must be finely regulated to ensure the survival of the species that produces them. The process that leads to successful fruit formation starts at early stages of floral meristem development and follows a series of chronologically successive events. In this work we report the functional characterization of the class-II homeodomain leucine zipper (HD-ZIP) JAIBA (JAB) gene. Mutant jab plants show sporophytic defects in male and female reproductive development, and combined with crabs claw cause defects in the floral meristem (FM) determination process and gynoecium medial tissue development. This suggests that proper FM determination is required for gynoecium medial tissue development, and indicates that JAB and CRC are necessary for both processes. Furthermore, the JAB protein interacts with transcription factors known to regulate meristematic activity, fruit development, and floral meristem determinacy. The sporophytic effect on pollen and embryo sac development might be an independent and later function of JAB. In summary, we present data that indicates that the JAB gene regulates meristematic activity in different tissues, and that it is necessary for the correct formation of the gynoecium at different stages, contributing to a crucial process in plant life: proper fruit development. PMID:22409594

  19. RECIPES FOR WRITING ALGORITHMS FOR ATMOSPHERIC CORRECTIONS AND TEMPERATURE/EMISSIVITY SEPARATIONS IN THE THERMAL REGIME FOR A MULTI-SPECTRAL SENSOR

    SciTech Connect

    C. BOREL; W. CLODIUS

    2001-04-01

    This paper discusses the algorithms created for the Multi-spectral Thermal Imager (MTI) to retrieve temperatures and emissivities. Recipes to create the physics based water temperature retrieval, emissivity of water surfaces are described. A simple radiative transfer model for multi-spectral sensors is developed. A method to create look-up-tables and the criterion of finding the optimum water temperature are covered. Practical aspects such as conversion from band-averaged radiances to brightness temperatures and effects of variations in the spectral response on the atmospheric transmission are discussed. A recipe for a temperature/emissivity separation algorithm when water surfaces are present is given. Results of retrievals of skin water temperatures are compared with in-situ measurements of the bulk water temperature at two locations are shown.

  20. Chromatographic background drift correction coupled with parallel factor analysis to resolve coelution problems in three-dimensional chromatographic data: quantification of eleven antibiotics in tap water samples by high-performance liquid chromatography coupled with a diode array detector.

    PubMed

    Yu, Yong-Jie; Wu, Hai-Long; Fu, Hai-Yan; Zhao, Juan; Li, Yuan-Na; Li, Shu-Fang; Kang, Chao; Yu, Ru-Qin

    2013-08-01

    Chromatographic background drift correction has been an important field of research in chromatographic analysis. In the present work, orthogonal spectral space projection for background drift correction of three-dimensional chromatographic data was described in detail and combined with parallel factor analysis (PARAFAC) to resolve overlapped chromatographic peaks and obtain the second-order advantage. This strategy was verified by simulated chromatographic data and afforded significant improvement in quantitative results. Finally, this strategy was successfully utilized to quantify eleven antibiotics in tap water samples. Compared with the traditional methodology of introducing excessive factors for the PARAFAC model to eliminate the effect of background drift, clear improvement in the quantitative performance of PARAFAC was observed after background drift correction by orthogonal spectral space projection.

  1. Hsp90 binds and regulates Gcn2, the ligand-inducible kinase of the alpha subunit of eukaryotic translation initiation factor 2 [corrected].

    PubMed

    Donzé, O; Picard, D

    1999-12-01

    The protein kinase Gcn2 stimulates translation of the yeast transcription factor Gcn4 upon amino acid starvation. Using genetic and biochemical approaches, we show that Gcn2 is regulated by the molecular chaperone Hsp90 in budding yeast Saccharomyces cerevisiae. Specifically, we found that (i) several Hsp90 mutant strains exhibit constitutive expression of a GCN4-lacZ reporter plasmid; (ii) Gcn2 and Hsp90 form a complex in vitro as well as in vivo; (iii) the specific inhibitors of Hsp90, geldanamycin and macbecin I, enhance the association of Gcn2 with Hsp90 and inhibit its kinase activity in vitro; (iv) in vivo, macbecin I strongly reduces the levels of Gcn2; (v) in a strain expressing the temperature-sensitive Hsp90 mutant G170D, both the accumulation and activity of Gcn2 are abolished at the restrictive temperature; and (vi) the Hsp90 cochaperones Cdc37, Sti1, and Sba1 are required for the response to amino acid starvation. Taken together, these data identify Gcn2 as a novel target for Hsp90, which plays a crucial role for the maturation and regulation of Gcn2. PMID:10567567

  2. Aureolegraph internal scattering correction.

    PubMed

    DeVore, John; Villanucci, Dennis; LePage, Andrew

    2012-11-20

    Two methods of determining instrumental scattering for correcting aureolegraph measurements of particulate solar scattering are presented. One involves subtracting measurements made with and without an external occluding ball and the other is a modification of the Langley Plot method and involves extrapolating aureolegraph measurements collected through a large range of solar zenith angles. Examples of internal scattering correction determinations using the latter method show similar power-law dependencies on scattering, but vary by roughly a factor of 8 and suggest that changing aerosol conditions during the determinations render this method problematic. Examples of corrections of scattering profiles using the former method are presented for a range of atmospheric particulate layers from aerosols to cumulus and cirrus clouds.

  3. Aureolegraph internal scattering correction.

    PubMed

    DeVore, John; Villanucci, Dennis; LePage, Andrew

    2012-11-20

    Two methods of determining instrumental scattering for correcting aureolegraph measurements of particulate solar scattering are presented. One involves subtracting measurements made with and without an external occluding ball and the other is a modification of the Langley Plot method and involves extrapolating aureolegraph measurements collected through a large range of solar zenith angles. Examples of internal scattering correction determinations using the latter method show similar power-law dependencies on scattering, but vary by roughly a factor of 8 and suggest that changing aerosol conditions during the determinations render this method problematic. Examples of corrections of scattering profiles using the former method are presented for a range of atmospheric particulate layers from aerosols to cumulus and cirrus clouds. PMID:23207299

  4. A CORRECTION.

    PubMed

    Johnson, D

    1940-03-22

    IN a recently published volume on "The Origin of Submarine Canyons" the writer inadvertently credited to A. C. Veatch an excerpt from a submarine chart actually contoured by P. A. Smith, of the U. S. Coast and Geodetic Survey. The chart in question is Chart IVB of Special Paper No. 7 of the Geological Society of America entitled "Atlantic Submarine Valleys of the United States and the Congo Submarine Valley, by A. C. Veatch and P. A. Smith," and the excerpt appears as Plate III of the volume fist cited above. In view of the heavy labor involved in contouring the charts accompanying the paper by Veatch and Smith and the beauty of the finished product, it would be unfair to Mr. Smith to permit the error to go uncorrected. Excerpts from two other charts are correctly ascribed to Dr. Veatch. PMID:17839404

  5. A CORRECTION.

    PubMed

    Johnson, D

    1940-03-22

    IN a recently published volume on "The Origin of Submarine Canyons" the writer inadvertently credited to A. C. Veatch an excerpt from a submarine chart actually contoured by P. A. Smith, of the U. S. Coast and Geodetic Survey. The chart in question is Chart IVB of Special Paper No. 7 of the Geological Society of America entitled "Atlantic Submarine Valleys of the United States and the Congo Submarine Valley, by A. C. Veatch and P. A. Smith," and the excerpt appears as Plate III of the volume fist cited above. In view of the heavy labor involved in contouring the charts accompanying the paper by Veatch and Smith and the beauty of the finished product, it would be unfair to Mr. Smith to permit the error to go uncorrected. Excerpts from two other charts are correctly ascribed to Dr. Veatch.

  6. Conductivity Cell Thermal Inertia Correction Revisited

    NASA Astrophysics Data System (ADS)

    Eriksen, C. C.

    2012-12-01

    Salinity measurements made with a CTD (conductivity-temperature-depth instrument) rely on accurate estimation of water temperature within their conductivity cell. Lueck (1990) developed a theoretical framework for heat transfer between the cell body and water passing through it. Based on this model, Lueck and Picklo (1990) introduced the practice of correcting for cell thermal inertia by filtering a temperature time series using two parameters, an amplitude α and a decay time constant τ, a practice now widely used. Typically these two parameters are chosen for a given cell configuration and internal flushing speed by a statistical method applied to a particular data set. Here, thermal inertia correction theory has been extended to apply to flow speeds spanning well over an order of magnitude, both within and outside a conductivity cell, to provide predictions of α and τ from cell geometry and composition. The extended model enables thermal inertia correction for the variable flows encountered by conductivity cells on autonomous gliders and floats, as well as tethered platforms. The length scale formed as the product of cell encounter speed of isotherms, α, and τ can be used to gauge the size of the temperature correction for a given thermal stratification. For cells flushed by dynamic pressure variation induced by platform motion, this length varies by less than a factor of 2 over more than a decade of speed variation. The magnitude of correction for free-flow flushed sensors is comparable to that of pumped cells, but at an order of magnitude in energy savings. Flow conditions around a cell's exterior are found to be of comparable importance to thermal inertia response as flushing speed. Simplification of cell thermal response to a single normal mode is most valid at slow speed. Error in thermal inertia estimation arises from both neglect of higher modes and numerical discretization of the correction scheme, both of which can be easily quantified

  7. Influence of sky view factor on outdoor thermal environment and physiological equivalent temperature

    NASA Astrophysics Data System (ADS)

    He, Xiaodong; Miao, Shiguang; Shen, Shuanghe; Li, Ju; Zhang, Benzhi; Zhang, Ziyue; Chen, Xiujie

    2015-03-01

    Sky view factor (SVF), which is an indicator of urban canyon geometry, affects the surface energy balance, local air circulation, and outdoor thermal comfort. This study focused on a continuous and long-term meteorological observation system to investigate the effects of SVF on outdoor thermal conditions and physiological equivalent temperature (PET) in the central business district (CBD) of Beijing (which is located within Chaoyang District), specifically addressed current knowledge gaps for SVF-PET relationships in cities with typical continental/microthermal climates. An urban sub-domain scale model and the RayMan model were used to diagnose wind fields and to calculate SVF and long-term PET, respectively. Analytical results show that the extent of shading contributes to variations in thermal perception distribution. Highly shaded areas (SVF <0.3) typically exhibit less frequent hot conditions during summer, while enduring longer periods of cold discomfort in winter than moderately shaded areas (0.3< SVF <0.5) and slightly shaded areas (SVF >0.5), and vice versa. Because Beijing has a monsoon-influenced humid continental climate with hot summers and long, cold, windy, and dry winters, a design project that ideally provides moderate shading should be planned to balance hot discomfort in summer and cold discomfort in winter, which effectively prolongs the comfort periods in outdoor spaces throughout the entire year. This research indicate that climate zone characteristics, urban environmental conditions, and thermal comfort requirements of residents must be accounted for in local-scale scientific planning and design, i.e., for urban canyon streets and residential estates.

  8. SU-E-T-552: Monte Carlo Calculation of Correction Factors for a Free-Air Ionization Chamber in Support of a National Air-Kerma Standard for Electronic Brachytherapy

    SciTech Connect

    Mille, M; Bergstrom, P

    2015-06-15

    Purpose: To use Monte Carlo radiation transport methods to calculate correction factors for a free-air ionization chamber in support of a national air-kerma standard for low-energy, miniature x-ray sources used for electronic brachytherapy (eBx). Methods: The NIST is establishing a calibration service for well-type ionization chambers used to characterize the strength of eBx sources prior to clinical use. The calibration approach involves establishing the well-chamber’s response to an eBx source whose air-kerma rate at a 50 cm distance is determined through a primary measurement performed using the Lamperti free-air ionization chamber. However, the free-air chamber measurements of charge or current can only be related to the reference air-kerma standard after applying several corrections, some of which are best determined via Monte Carlo simulation. To this end, a detailed geometric model of the Lamperti chamber was developed in the EGSnrc code based on the engineering drawings of the instrument. The egs-fac user code in EGSnrc was then used to calculate energy-dependent correction factors which account for missing or undesired ionization arising from effects such as: (1) attenuation and scatter of the x-rays in air; (2) primary electrons escaping the charge collection region; (3) lack of charged particle equilibrium; (4) atomic fluorescence and bremsstrahlung radiation. Results: Energy-dependent correction factors were calculated assuming a monoenergetic point source with the photon energy ranging from 2 keV to 60 keV in 2 keV increments. Sufficient photon histories were simulated so that the Monte Carlo statistical uncertainty of the correction factors was less than 0.01%. The correction factors for a specific eBx source will be determined by integrating these tabulated results over its measured x-ray spectrum. Conclusion: The correction factors calculated in this work are important for establishing a national standard for eBx which will help ensure that dose

  9. Temperature-dependent magnetostriction as the key factor for martensite reorientation in magnetic field

    NASA Astrophysics Data System (ADS)

    L’vov, Victor A.; Kosogor, Anna

    2016-09-01

    The magnetic field application leads to spatially inhomogeneous magnetostriction of twinned ferromagnetic martensite. When the increasing field and magnetostrictive strain reach certain threshold values, the motion of twin boundaries and magnetically induced reorientation (MIR) of twinned martensite start. The MIR leads to giant magnetically induced deformation of twinned martensite. In the present article, the threshold field (TF) and temperature range of observability of MIR were calculated for the Ni–Mn–Ga martensite assuming that the threshold strain (TS) is temperature-independent. The calculations show that if the TS is of the order of 10‑4, the TF strongly depends on temperature and MIR can be observed only above the limiting temperature (~220 K). If the TS is of the order of 10‑6, the TF weakly depends on temperature and MIR can be observed at extremely low temperatures. The obtained theoretical results are in agreement with available experimental data.

  10. Temperature-dependent magnetostriction as the key factor for martensite reorientation in magnetic field

    NASA Astrophysics Data System (ADS)

    L'vov, Victor A.; Kosogor, Anna

    2016-09-01

    The magnetic field application leads to spatially inhomogeneous magnetostriction of twinned ferromagnetic martensite. When the increasing field and magnetostrictive strain reach certain threshold values, the motion of twin boundaries and magnetically induced reorientation (MIR) of twinned martensite start. The MIR leads to giant magnetically induced deformation of twinned martensite. In the present article, the threshold field (TF) and temperature range of observability of MIR were calculated for the Ni-Mn-Ga martensite assuming that the threshold strain (TS) is temperature-independent. The calculations show that if the TS is of the order of 10-4, the TF strongly depends on temperature and MIR can be observed only above the limiting temperature (~220 K). If the TS is of the order of 10-6, the TF weakly depends on temperature and MIR can be observed at extremely low temperatures. The obtained theoretical results are in agreement with available experimental data.

  11. Survival of manure-borne and fecal coliforms in soil: temperature dependence as affected by site-specific factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding pathogenic and indicator bacteria survival in soils is essential for assessing the potential of microbial contamination of water and produce, and making appropriate management decisions. The objective of this work was to evaluate effects of soil and management factors on temperature de...

  12. Role of electronic correlation in high-low temperature phase transition of hexagonal nickel sulfide: a comparative density functional theory study with and without correction for on-site Coulomb interaction.

    PubMed

    Zhang, Wei-Bing; Li, Jie; Tang, Bi-Yu

    2013-06-28

    The structural, electronic, magnetic, and elastic properties of hexagonal nickel sulfide (NiS) have been investigated comparatively by Density Functional theory (DFT) and DFT plus correction for on-site Coulomb interaction (DFT+U), in which two different exchange correlation functionals local density approximations (LDA) and general gradient approximations (GGA) in the form of Perdew-Burke-Ernzerhof (PBE) are used. Our results indicate LDA and PBE methods predict hexagonal NiS to be a paramagnetic metal whereas LDA(PBE)+U calculations with reasonable on-site Coulomb interaction energy give the antiferromagnetic insulating state of low temperature hexagonal NiS successfully. Meanwhile, compared with LDA(PBE) results, LDA(PBE)+U methods give larger lattice parameters, crystal volume, and shear constant c44, consistent with the experimental picture during high-low temperature phase transition of hexagonal NiS, in which an increase of the shear constant c44 and lattice parameters were found in the low-temperature antiferromagnetic phase. The present DFT and DFT+U calculations provide a reasonable description for the properties of high temperature and low temperature hexagonal NiS respectively, which indicates that electronic correlation is responsible for this high-low temperature phase transition.

  13. Atmospheric corrections for TIMS estimated emittance

    NASA Technical Reports Server (NTRS)

    Warner, T. A.; Levandowski, D. W.

    1992-01-01

    The estimated temperature of the average of 500 lines of Thermal Infrared Multispectral Scanner (TIMS) data of the Pacific Ocean, from flight line 94, collected on 30 Sep. 1988, at 1931 GMT is shown. With no atmospheric corrections, estimated temperature decreases away from nadir (the center of the scan line). A LOWTRAN modeled correction, using local radiosonde data and instrument scan angle information, results in reversed limb darkening effects for most bands, and does not adequately correct all bands to the same temperature. The atmosphere tends to re-radiate energy at the wavelengths at which it most absorbs, and thus the overall difference between corrected and uncorrected temperatures is approximately 40 C, despite the average LOWTRAN calculated transmittance of only 60 percent between 8.1 and 11.6 microns. An alternative approach to atmospheric correction is a black body normalization. This is done by calculating a normalization factor for each pixel position and wavelength, which when applied results in a single calculated temperature, as would be expected for a gray body with near uniform emittance. The black body adjustment is based on the atmospheric conditions over the sea. The ground elevation profile along the remaining 3520 scan lines (approximately 10 km) of flight line 94, up the slopes of Kilauea, determined from aircraft pressure and laser altimeter data is shown. This flight line includes a large amount of vegetation that is clearly discernible on the radiance image, being much cooler than the surrounding rocks. For each of the 3520 scan lines, pixels were classified as vegetation or 'other'. A moving average of 51 lines was applied to the composite vegetation emittance for each scan line, to reduce noise. Assuming vegetation to be like water, and to act as gray body with an emittance of 0.986 across the spectrum, it is shown that that the LOWTRAN induced artifacts are severe, and other than for the 0.9.9 micron channel, not significantly

  14. In Situ Mosaic Brightness Correction

    NASA Technical Reports Server (NTRS)

    Deen, Robert G.; Lorre, Jean J.

    2012-01-01

    In situ missions typically have pointable, mast-mounted cameras, which are capable of taking panoramic mosaics comprised of many individual frames. These frames are mosaicked together. While the mosaic software applies radiometric correction to the images, in many cases brightness/contrast seams still exist between frames. This is largely due to errors in the radiometric correction, and the absence of correction for photometric effects in the mosaic processing chain. The software analyzes the overlaps between adjacent frames in the mosaic and determines correction factors for each image in an attempt to reduce or eliminate these brightness seams.

  15. Influence of some psychological factors on temperature dynamics of human hands

    NASA Astrophysics Data System (ADS)

    Koreneva, L. G.; Apenisheva, N. P.; Zakharov, Pavel V.; Markov, A. G.

    1993-11-01

    Temperature dynamics of the hands of human subjects was investigated by means of dynamical thermography and shown to depend on the personality and psychological conditions of the subjects. For neurotic personalities, especially under stress, the temperature is shown not to change at all in most cases. Stress resistant `independent' persons show very stable dynamics with relatively small temperature changes (about 2 degrees). The dependence of temperature patterns of `intermediate,' or `active,' personalities on the conditions of stress, mental concentration, and so on, is discussed.

  16. An improved temperature index model for alpine glaciers using derived degree-day factors from climatic inputs

    NASA Astrophysics Data System (ADS)

    Keeler, D. G.; Havens, A. P.; Rupper, S.; Christensen, W. F.

    2013-12-01

    Glacier melt rates are strongly affected by minor perturbations in climatic systems. Quantifying changes in glacier melt rates is therefore important, particularly in areas where melt-water contributes to hydroelectric power generation, irrigation, or flood risks. Several methods currently exist for modeling glacier melt rates, but one widely used method is temperature index modeling, also called positive degree-day modeling. This model is often applied due to its simplicity and small number of input variables, but it still depends on an empirically-measured scaling constant (the degree-day factor). These degree-day factors can vary by a factor of five from one glacier to the next, complicating the applicability of the approach to new regions, or to different time periods. Previous work suggests the degree-day factor may be a function of the surface albedo, solar radiation, and near-surface air temperature. Thus, it is possible the degree-day factor itself is predictable. In this study we present a method to derive these melt factors directly from easily obtained climatic variables, thus allowing for the ready application of temperature index modeling to a much wider suite of glaciers with greater accuracy. We used a full energy-balance model to calculate possible degree-day factors over the full range of climate conditions commonly encountered with alpine glaciers. We then constructed a statistical emulator (a linear model which considers numerous interactions and polynomial effects) using select climate variables (insolation, positive degree-days, and albedo) as inputs. The statistical model is tuned using the energy-balance output as training data. The model skill will be tested against a suite of empirically-derived degree-day factors. These results would allow for the application of more accurate glacier melt models with quantified uncertainties to under-sampled glacial regions and paleoclimate reconstructions.

  17. A hypothesis about factors that affect maximum stream temperatures across montane landscapes

    USGS Publications Warehouse

    Isaak, D.J.; Hubert, W.A.

    2001-01-01

    Temperature is an important variable structuring lotic biotas, but little is known about how montane landscapes function to determine stream temperatures. We developed an a priori hypothesis that was used to predict how watershed elements would interact to affect stream temperatures. The hypothesis was tested in a series of path analyses using temperature data from 26 sites on second-order to fourth-order streams across a fifth-order Rocky Mountain watershed. Based on the performance of the first hypothesis, two revised versions of the hypothesis were developed and tested that proved to be more accurate than the original hypothesis. The most plausible of the revised hypotheses accounted for 82 percent of the variation in maximum stream temperature, had a predicted data structure that did not deviate from the empirical data structure, and was the most parsimonious. The final working hypothesis suggested that stream temperature maxima were directly controlled by a large negative effect from mean basin elevation (direct effect = -0.57, p < 0.01) and smaller effects from riparian tree abundance (direct effect = -0.28, p = 0.03), and cattle density (direct effect = 0.24, p = 0.05). Watershed slope, valley constraint, and the abundance of grass across a watershed also affected temperature maxima, but these effects were indirect and mediated through cattle density and riparian trees. Three variables included in the a priori hypothesis - watershed aspect, stream width, and watershed size - had negligible effects on maximum stream temperatures and were omitted from the final working hypothesis.

  18. SUMMER STREAM TEMPERATURES, JUVENILE COHO CONDITION FACTORS AND BLACK SPOT INFECTION IN THE OREGON COAST RANGE

    EPA Science Inventory

    We monitored stream temperatures at 35 locations throughout the West Fork Smith River watershed in the Oregon Coast Range during the summer of 2002. Between July 24 and August 24, maximum seven-day moving average high daily temperatures ranged from 21.8 C near the catchment's mo...

  19. Dominant factors affecting temperature rise in simulations of human thermoregulation during RF exposure

    NASA Astrophysics Data System (ADS)

    Laakso, Ilkka; Hirata, Akimasa

    2011-12-01

    Numerical models of the human thermoregulatory system can be used together with realistic voxel models of the human anatomy to simulate the body temperature increases caused by the power absorption from radio-frequency electromagnetic fields. In this paper, the Pennes bioheat equation with a thermoregulatory model is used for calculating local peak temperatures as well as the body-core-temperature elevation in a realistic human body model for grounded plane-wave exposures at frequencies 39, 800 and 2400 MHz. The electromagnetic power loss is solved by the finite-difference time-domain (FDTD) method, and the discretized bioheat equation is solved by the geometric multigrid method. Human thermoregulatory models contain numerous thermophysiological and computational parameters—some of which may be subject to considerable uncertainty—that affect the simulated core and local temperature elevations. The goal of this paper is to find how greatly the computed temperature is influenced by changes in various modelling parameters, such as the skin blood flow rate, models for vasodilation and sweating, and clothing and air movement. The results show that the peak temperature rises are most strongly affected by the modelling of tissue blood flow and its temperature dependence, and mostly unaffected by the central control mechanism for vasodilation and sweating. Almost the opposite is true for the body-core-temperature rise, which is however typically greatly lower than the peak temperature rise. It also seems that ignoring the thermoregulation and the blood temperature increase is a good approximation when the local 10 g averaged specific absorption rate is smaller than 10 W kg-1.

  20. Correcting Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) High Altitude (40 - 65 km) Temperature Retrievals for Instrumental Correlated Noise and Biases

    NASA Astrophysics Data System (ADS)

    McConnochie, T. H.; Smith, M. D.

    2011-12-01

    Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) nadir-soundings have been used to derive atmospheric temperatures up to roughly 40 km [Conrath et al., JGR 105 2000, Smith et al., JGR 106, 2001], and MGS-TES limb soundings have been used to extend the atmospheric temperature data set to > 60 km in altitude [Smith et al., JGR 106, 2001]. The ~40 - ~65 km altitude range probed by the MGS-TES limb sounding is particularly important for capturing key dynamical features such as the warm winter polar mesosphere [e.g., Smith et al., JGR 106, 2001; McCleese et al., Nature Geoscience 1, 2008], and the response of thermal tides to dust opacity [e.g. Wilson and Hamilton, J. Atmos. Sci. 53, 1996]. Thus accurate and precise temperature profiles at these altitudes are particularly important for constraining global circulation models. They are also critical for interpreting observations of mesospheric condensate aerosols [e.g., Määttänen et al., Icarus 209, 2010; McConnochie et al., Icarus 210, 2010)]. We have indentified correlated noise components in the MGS-TES limb sounding radiances that propagate into very large uncertainties in the retrieved temperatures. We have also identified a slowly varying radiance bias in the limb sounding radiances. Note that the nadir-sounding-based MGS-TES atmospheric temperatures currently available from the Planetary Data System are not affected by either of these issues. These two issues affect the existing MGS-TES limb sounding temperature data set are as follows: Considering, for example, the 1.5 Pascal pressure level (which typically falls between 50 and 60 km altitude), correlated-noise induced standard errors for individual limb-sounding temperature retrievals were 3 - 5 K in Mars Year 24, rising to 5 - 15 K in Mars Year 25 and 10 - 15 K in Mars Year 26 and 27. The radiance bias, although consistent on ~10-sol time scales, is highly variable over the course of the MGS-TES mission. It results in temperatures (at the 1

  1. Resource supply overrides temperature as a controlling factor of marine phytoplankton growth.

    PubMed

    Marañón, Emilio; Cermeño, Pedro; Huete-Ortega, María; López-Sandoval, Daffne C; Mouriño-Carballido, Beatriz; Rodríguez-Ramos, Tamara

    2014-01-01

    The universal temperature dependence of metabolic rates has been used to predict how ocean biology will respond to ocean warming. Determining the temperature sensitivity of phytoplankton metabolism and growth is of special importance because this group of organisms is responsible for nearly half of global primary production, sustains most marine food webs, and contributes to regulate the exchange of CO2 between the ocean and the atmosphere. Phytoplankton growth rates increase with temperature under optimal growth conditions in the laboratory, but it is unclear whether the same degree of temperature dependence exists in nature, where resources are often limiting. Here we use concurrent measurements of phytoplankton biomass and carbon fixation rates in polar, temperate and tropical regions to determine the role of temperature and resource supply in controlling the large-scale variability of in situ metabolic rates. We identify a biogeographic pattern in phytoplankton metabolic rates, which increase from the oligotrophic subtropical gyres to temperate regions and then coastal waters. Variability in phytoplankton growth is driven by changes in resource supply and appears to be independent of seawater temperature. The lack of temperature sensitivity of realized phytoplankton growth is consistent with the limited applicability of Arrhenius enzymatic kinetics when substrate concentrations are low. Our results suggest that, due to widespread resource limitation in the ocean, the direct effect of sea surface warming upon phytoplankton growth and productivity may be smaller than anticipated.

  2. The impact of climatic and non-climatic factors on land surface temperature in southwestern Romania

    NASA Astrophysics Data System (ADS)

    Roşca, Cristina Florina; Harpa, Gabriela Victoria; Croitoru, Adina-Eliza; Herbel, Ioana; Imbroane, Alexandru Mircea; Burada, Doina Cristina

    2016-09-01

    Land surface temperature is one of the most important parameters related to global warming. It depends mainly on soil type, discontinuous vegetation cover, or lack of precipitation. The main purpose of this paper is to investigate the relationship between high LST, synoptic conditions and air masses trajectories, vegetation cover, and soil type in one of the driest region in Romania. In order to calculate the land surface temperature and normalized difference vegetation index, five satellite images of LANDSAT missions 5 and 7, covering a period of 26 years (1986-2011), were selected, all of them collected in the month of June. The areas with low vegetation density were derived from normalized difference vegetation index, while soil types have been extracted from Corine Land Cover database. HYSPLIT application was employed to identify the air masses origin based on their backward trajectories for each of the five study cases. Pearson, logarithmic, and quadratic correlations were used to detect the relationships between land surface temperature and observed ground temperatures, as well as between land surface temperature and normalized difference vegetation index. The most important findings are: strong correlation between land surface temperature derived from satellite images and maximum ground temperature recorded in a weather station located in the area, as well as between areas with land surface temperature equal to or higher than 40.0 °C and those with lack of vegetation; the sandy soils are the most prone to high land surface temperature and lack of vegetation, followed by the chernozems and brown soils; extremely severe drought events may occur in the region.

  3. Temperature dependent barrier height and ideality factor of electrodeposited n-CdSe/Cu Schottky barrier diode

    SciTech Connect

    Mahato, S. Shiwakoti, N.; Kar, A. K.

    2015-06-24

    This article reports the measurement of temperature-dependent barrier height and ideality factor of n-CdSe/Cu Schottky barrier diode. The Cadmium Selenide (CdSe) thin films have been deposited by simple electrodeposition technique. The XRD measurements ravels the deposited single phase CdSe films are highly oriented on (002) plane and the average particle size has been calculated to be ~18 nm. From SEM characterization, it is clear that the surface of CdSe thin films are continuous, homogeneous and the film is well adhered to the substrate and consists of fine grains which are irregular in shape and size. Current-Voltage characteristics have been measured at different temperatures in the range (298 K – 353 K). The barrier height and ideality factor are found to be strongly temperature dependent. The inhomogenious barrier height increases and ideality factor decreases with increase in temperature. The expectation value has been calculated and its value is 0.30 eV.

  4. Accumulation of fatty acids in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoAcarboxylase, temperature, and co-immobilization with Azospirillum brasilense [corrected].

    PubMed

    Leyva, Luis A; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.

  5. Factors affecting temperature variation and habitat use in free-ranging diamondback terrapins.

    PubMed

    Akins, C D; Ruder, C D; Price, S J; Harden, L A; Gibbons, J W; Dorcas, M E

    2014-08-01

    Measuring the thermal conditions of aquatic reptiles with temperature dataloggers is a cost-effective way to study their behavior and habitat use. Temperature dataloggers are a particularly useful and informative approach to studying organisms such as the estuarine diamondback terrapin (Malaclemys terrapin) that inhabits a dynamic environment often inaccessible to researchers. We used carapace-mounted dataloggers to measure hourly carapace temperature (Tc) of free-ranging terrapins in South Carolina from October 2007 to 2008 to examine the effects of month, sex, creek site, and tide on Tc and to determine the effects of month, sex, and time of day on terrapin basking frequency. Simultaneous measurements of environmental temperatures (Te; shallow mud, deep mud, water) allowed us to make inferences about terrapin microhabitat use. Terrapin Tc differed significantly among months and creek and between sexes. Terrapin microhabitat use also varied monthly, with shallow mud temperature being the best predictor of Tc November-March and water temperature being the best predictor of Tc April-October. Terrapins basked most frequently in spring and fall and males basked more frequently than females. Our study contributes to a fuller understanding of terrapin thermal biology and provides support for using dataloggers to investigate behavior and habitat use of aquatic ectotherms inhabiting dynamic environments.

  6. Factors affecting temperature variation and habitat use in free-ranging diamondback terrapins.

    PubMed

    Akins, C D; Ruder, C D; Price, S J; Harden, L A; Gibbons, J W; Dorcas, M E

    2014-08-01

    Measuring the thermal conditions of aquatic reptiles with temperature dataloggers is a cost-effective way to study their behavior and habitat use. Temperature dataloggers are a particularly useful and informative approach to studying organisms such as the estuarine diamondback terrapin (Malaclemys terrapin) that inhabits a dynamic environment often inaccessible to researchers. We used carapace-mounted dataloggers to measure hourly carapace temperature (Tc) of free-ranging terrapins in South Carolina from October 2007 to 2008 to examine the effects of month, sex, creek site, and tide on Tc and to determine the effects of month, sex, and time of day on terrapin basking frequency. Simultaneous measurements of environmental temperatures (Te; shallow mud, deep mud, water) allowed us to make inferences about terrapin microhabitat use. Terrapin Tc differed significantly among months and creek and between sexes. Terrapin microhabitat use also varied monthly, with shallow mud temperature being the best predictor of Tc November-March and water temperature being the best predictor of Tc April-October. Terrapins basked most frequently in spring and fall and males basked more frequently than females. Our study contributes to a fuller understanding of terrapin thermal biology and provides support for using dataloggers to investigate behavior and habitat use of aquatic ectotherms inhabiting dynamic environments. PMID:25086975

  7. Experimental determination of field factors (\\Omega _{{{Q}_{\\text{clin}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{clin}}},{{f}_{\\text{msr}}}} ) for small radiotherapy beams using the daisy chain correction method

    NASA Astrophysics Data System (ADS)

    Lárraga-Gutiérrez, José Manuel

    2015-08-01

    Recently, Alfonso et al proposed a new formalism for the dosimetry of small and non-standard fields. The proposed new formalism is strongly based on the calculation of detector-specific beam correction factors by Monte Carlo simulation methods, which accounts for the difference in the response of the detector between the small and the machine specific reference field. The correct calculation of the detector-specific beam correction factors demands an accurate knowledge of the linear accelerator, detector geometry and composition materials. The present work shows that the field factors in water may be determined experimentally using the daisy chain correction method down to a field size of 1 cm  ×  1 cm for a specific set of detectors. The detectors studied were: three mini-ionization chambers (PTW-31014, PTW-31006, IBA-CC01), three silicon-based diodes (PTW-60018, IBA-SFD and IBA-PFD) and one synthetic diamond detector (PTW-60019). Monte Carlo simulations and experimental measurements were performed for a 6 MV photon beam at 10 cm depth in water with a source-to-axis distance of 100 cm. The results show that the differences between the experimental and Monte Carlo calculated field factors are less than 0.5%—with the exception of the IBA-PFD—for field sizes between 1.5 cm  ×  1.5 cm and 5 cm  ×  5 cm. For the 1 cm  ×  1 cm field size, the differences are within 2%. By using the daisy chain correction method, it is possible to determine measured field factors in water. The results suggest that the daisy chain correction method is not suitable for measurements performed with the IBA-PFD detector. The latter is due to the presence of tungsten powder in the detector encapsulation material. The use of Monte Carlo calculated k{{Q\\text{clin}},{{Q}\\text{msr}}}{{f\\text{clin}},{{f}\\text{msr}}} is encouraged for field sizes less than or equal to 1 cm  ×  1 cm for the dosimeters used in this work.

  8. Plans for Jet Energy Corrections at CMS

    NASA Astrophysics Data System (ADS)

    Mishra, Kalanand

    2009-05-01

    We present a plan for Jet Energy Corrections at CMS. Jet corrections at CMS will come initially from simulation tuned on test beam data, directly from collision data when available, and ultimately from a simulation tuned on collision data. The corrections will be factorized into a fixed sequence of sub-corrections associated with different detector and physics effects. The following three factors are minimum requirements for most analysis: offset corrections for pile-up and noise; correction for the response of the calorimeter as a function of jet pseudorapidity relative to the barrel; correction for the absolute response as a function of transverse momentum in the barrel. The required correction gives a jet Lorentz vector equivalent to the sum of particles in the jet cone emanating from a QCD hard collision. We discuss the status of these corrections, the planned data-driven techniques for their derivation, and their anticipated evolution with the stages of the CMS experiment.

  9. Ambient temperature: a factor affecting performance and physiological response of broiler chickens

    NASA Astrophysics Data System (ADS)

    Donkoh, A.

    1989-12-01

    An experiment was conducted to elucidate the influence of four constant ambient temperatures (20°, 25°, 30° and 35°C) on the performance and physiological reactions of male commercial broiler chicks from 3 to 7 weeks of age. A 12 h light-dark cycle was operated, while relative humidity and air circulation were not controlled. Exposure of broiler chickens to the 20°, 25°, 30° and 35°C treatments showed highly significant ( P<0.0001) depression in growth rate, food intake and efficiency of food utilization, and a significant increase in water consumption for the 30° and 35°C groups. Mortality was, however, not affected by the temperature treatments. Changes in physiological status, such as increased rectal temperatures, decreased concentration of red blood cells, haemoglobin, haematocrit, and total plasma protein were observed in birds housed in the higher temperature (30° and 35°C) environments. Moreover, in these broiler chickens, there was an increased blood glucose concentration and a decreased thyroid gland weight. These results indicate that continuous exposure of broiler chickens to high ambient temperatures markedly affects their performance and physiological response.

  10. Uncovering Different Masking Factors on Wrist Skin Temperature Rhythm in Free-Living Subjects

    PubMed Central

    Martinez-Nicolas, Antonio; Ortiz-Tudela, Elisabet; Rol, Maria Angeles; Madrid, Juan Antonio

    2013-01-01

    Most circadian rhythms are controlled by a major pacemaker located in the hypothalamic suprachiasmatic nucleus. Some of these rhythms, called marker rhythms, serve to characterize the timing of the internal temporal order. However, these variables are susceptible to masking effects as the result of activity, body position, light exposure, environmental temperature and sleep. Recently, wrist skin temperature (WT) has been proposed as a new index for evaluating circadian system status. In light of previous evidence suggesting the important relationship between WT and core body temperature regulation, the aim of this work was to purify the WT pattern in order to obtain its endogenous rhythm with the application of multiple demasking procedures. To this end, 103 subjects (18–24 years old) were recruited and their WT, activity, body position, light exposure, environmental temperature and sleep were recorded under free-living conditions for 1 week. WT demasking by categories or intercepts was applied to simulate a “constant routine” protocol (awakening, dim light, recumbent position, low activity and warm environmental temperature). Although the overall circadian pattern of WT was similar regardless of the masking effects, its amplitude was the rhythmic parameter most affected by environmental conditions. The acrophase and mesor were determined to be the most robust parameters for characterizing this rhythm. In addition, a circadian modulation of the masking effect was found for each masking variable. WT rhythm exhibits a strong endogenous component, despite the existence of multiple external influences. This was evidenced by simultaneously eliminating the influence of activity, body position, light exposure, environmental temperature and sleep. We therefore propose that it could be considered a valuable and minimally-invasive means of recording circadian physiology in ambulatory conditions. PMID:23577201

  11. Uncovering different masking factors on wrist skin temperature rhythm in free-living subjects.

    PubMed

    Martinez-Nicolas, Antonio; Ortiz-Tudela, Elisabet; Rol, Maria Angeles; Madrid, Juan Antonio

    2013-01-01

    Most circadian rhythms are controlled by a major pacemaker located in the hypothalamic suprachiasmatic nucleus. Some of these rhythms, called marker rhythms, serve to characterize the timing of the internal temporal order. However, these variables are susceptible to masking effects as the result of activity, body position, light exposure, environmental temperature and sleep. Recently, wrist skin temperature (WT) has been proposed as a new index for evaluating circadian system status. In light of previous evidence suggesting the important relationship between WT and core body temperature regulation, the aim of this work was to purify the WT pattern in order to obtain its endogenous rhythm with the application of multiple demasking procedures. To this end, 103 subjects (18-24 years old) were recruited and their WT, activity, body position, light exposure, environmental temperature and sleep were recorded under free-living conditions for 1 week. WT demasking by categories or intercepts was applied to simulate a "constant routine" protocol (awakening, dim light, recumbent position, low activity and warm environmental temperature). Although the overall circadian pattern of WT was similar regardless of the masking effects, its amplitude was the rhythmic parameter most affected by environmental conditions. The acrophase and mesor were determined to be the most robust parameters for characterizing this rhythm. In addition, a circadian modulation of the masking effect was found for each masking variable. WT rhythm exhibits a strong endogenous component, despite the existence of multiple external influences. This was evidenced by simultaneously eliminating the influence of activity, body position, light exposure, environmental temperature and sleep. We therefore propose that it could be considered a valuable and minimally-invasive means of recording circadian physiology in ambulatory conditions.

  12. Alternate corrections for estimating actual wetland evapotranspiration from potential evapotranspiration

    USGS Publications Warehouse

    Barclay, Shoemaker W.; Sumner, D.M.

    2006-01-01

    Corrections can be used to estimate actual wetland evapotranspiration (AET) from potential evapotranspiration (PET) as a means to define the hydrology of wetland areas. Many alternate parameterizations for correction coefficients for three PET equations are presented, covering a wide range of possible data-availability scenarios. At nine sites in the wetland Everglades of south Florida, USA, the relatively complex PET Penman equation was corrected to daily total AET with smaller standard errors than the PET simple and Priestley-Taylor equations. The simpler equations, however, required less data (and thus less funding for instrumentation), with the possibility of being corrected to AET with slightly larger, comparable, or even smaller standard errors. Air temperature generally corrected PET simple most effectively to wetland AET, while wetland stage and humidity generally corrected PET Priestley-Taylor and Penman most effectively to wetland AET. Stage was identified for PET Priestley-Taylor and Penman as the data type with the most correction ability at sites that are dry part of each year or dry part of some years. Finally, although surface water generally was readily available at each monitoring site, AET was not occurring at potential rates, as conceptually expected under well-watered conditions. Apparently, factors other than water availability, such as atmospheric and stomata resistances to vapor transport, also were limiting the PET rate. ?? 2006, The Society of Wetland Scientists.

  13. Role of Hot Water System Design on Factors Influential to Pathogen Regrowth: Temperature, Chlorine Residual, Hydrogen Evolution, and Sediment

    PubMed Central

    Brazeau, Randi H.; Edwards, Marc A.

    2013-01-01

    Abstract Residential water heating is linked to growth of pathogens in premise plumbing, which is the primary source of waterborne disease in the United States. Temperature and disinfectant residual are critical factors controlling increased concentration of pathogens, but understanding of how each factor varies in different water heater configurations is lacking. A direct comparative study of electric water heater systems was conducted to evaluate temporal variations in temperature and water quality parameters including dissolved oxygen levels, hydrogen evolution, total and soluble metal concentrations, and disinfectant decay. Recirculation tanks had much greater volumes of water at temperature ranges with potential for increased pathogen growth when set at 49°C compared with standard tank systems without recirculation. In contrast, when set at the higher end of acceptable ranges (i.e., 60°C), this relationship was reversed and recirculation systems had less volume of water at risk for pathogen growth compared with conventional systems. Recirculation tanks also tended to have much lower levels of disinfectant residual (standard systems had 40–600% higher residual), 4–6 times as much hydrogen, and 3–20 times more sediment compared with standard tanks without recirculation. On demand tankless systems had very small volumes of water at risk and relatively high levels of disinfectant residual. Recirculation systems may have distinct advantages in controlling pathogens via thermal disinfection if set at 60°C, but these systems have lower levels of disinfectant residual and greater volumes at risk if set at lower temperatures. PMID:24170969

  14. The analysis of anthropogenic factors in regional temperature change over East Asia

    NASA Astrophysics Data System (ADS)

    Guan, Xiaodan; Huang, Jianping; Guo, Ruixia

    2015-04-01

    In this study, the variability of surface air temperature (SAT) over different types of regions in East Asia are studied by using observation data from 1980-2012 under fast developing in economic. We found that the warming trends of the semi-arid regions are higher than other lands, which have increased 2.42°C as compared to the global annual mean temperature increase of 1.13°C over land. To investigate the causes of Enhanced Semi-Arid Warming (ESAW), we used an advanced dynamic-adjusted method proposed by Wallace et al. (2012) to analyse the adjusted temperature change. Our results point that the aerosol maybe takes the main role in adjusted temperature, especially in cold season. The anthropogenic-warming peak over semi-arid region plays the main role in the ESAW. Such anthropogenic-warming peak may be related to the long wave radiation change induced by aerosol in the air or the reduction of snow cover due to black carbon (BC) emission by fuels for winter residential heating. Besides the impact of aerosol over semi-arid region, the agricultural mulch creation, wind farms and other types of human activities may also make attribution to local SAT changes that need to be further studied.

  15. Radiosondes Corrected for Inaccuracy in RH Measurements

    DOE Data Explorer

    Miloshevich, Larry

    2008-01-15

    Corrections for inaccuracy in Vaisala radiosonde RH measurements have been applied to ARM SGP radiosonde soundings. The magnitude of the corrections can vary considerably between soundings. The radiosonde measurement accuracy, and therefore the correction magnitude, is a function of atmospheric conditions, mainly T, RH, and dRH/dt (humidity gradient). The corrections are also very sensitive to the RH sensor type, and there are 3 Vaisala sensor types represented in this dataset (RS80-H, RS90, and RS92). Depending on the sensor type and the radiosonde production date, one or more of the following three corrections were applied to the RH data: Temperature-Dependence correction (TD), Contamination-Dry Bias correction (C), Time Lag correction (TL). The estimated absolute accuracy of NIGHTTIME corrected and uncorrected Vaisala RH measurements, as determined by comparison to simultaneous reference-quality measurements from Holger Voemel's (CU/CIRES) cryogenic frostpoint hygrometer (CFH), is given by Miloshevich et al. (2006).

  16. Electronic measurement correction devices

    SciTech Connect

    Mahns, R.R.

    1984-04-01

    The electronics semi-conductor revolution has touched every industry and home in the nation. The gas industry is no exception. Sophisticated gas measurement instrumentation has been with us for several decades now, but only in the last 10 years or so has it really begun to boom. First marketed were the flow computers dedicated to orifice meter measurement; but with steadily decreasing manufacturing costs, electronic instrumentation is now moving into the area of base volume, pressure and temperature correction previously handled almost solely by mechanical integrating instruments. This paper takes a brief look at some of the features of the newcomers on the market and how they stack up against the old standby mechanical base volume/pressure/temperature correctors.

  17. Influence of temperature on symptom expression, detection of host factors in virus infected Piper nigrum L.

    PubMed

    Umadevi, P; Bhat, A I; Krishnamurthy, K S; Anandaraj, M

    2016-05-01

    Expression of symptoms in black pepper plants (Piper nigrum) infected with Piper yellow mottle virus (PYMoV) vary depending on the season, being high during summer months. Here, we explored the influence of temperature on symptom expression in PYMoV infected P. nigrum. Our controlled environment study revealed increase in virus titer, total proteins, IAA and reducing sugars when exposed to temperature stress. There was change in the 2-D separated protein before and after exposure. The 2-D proteomics LC-MS identified host and viral proteins suggesting virus-host interaction during symptom expression. The analysis as well as detection of host biochemical compounds may help in understanding the detailed mechanisms underlying the viral replication and damage to the crop, and thereby plan management strategies.

  18. Influence of temperature on symptom expression, detection of host factors in virus infected Piper nigrum L.

    PubMed

    Umadevi, P; Bhat, A I; Krishnamurthy, K S; Anandaraj, M

    2016-05-01

    Expression of symptoms in black pepper plants (Piper nigrum) infected with Piper yellow mottle virus (PYMoV) vary depending on the season, being high during summer months. Here, we explored the influence of temperature on symptom expression in PYMoV infected P. nigrum. Our controlled environment study revealed increase in virus titer, total proteins, IAA and reducing sugars when exposed to temperature stress. There was change in the 2-D separated protein before and after exposure. The 2-D proteomics LC-MS identified host and viral proteins suggesting virus-host interaction during symptom expression. The analysis as well as detection of host biochemical compounds may help in understanding the detailed mechanisms underlying the viral replication and damage to the crop, and thereby plan management strategies. PMID:27319055

  19. The effects of incomplete annealing on the temperature dependence of sheet resistance and gage factor in aluminum and phosphorus implanted silicon on sapphire

    NASA Technical Reports Server (NTRS)

    Pisciotta, B. P.; Gross, C.

    1976-01-01

    Partial annealing of damage to the crystal lattice during ion implantation reduces the temperature coefficient of resistivity of ion-implanted silicon, while facilitating controlled doping. Reliance on this method for temperature compensation of the resistivity and strain-gage factor is discussed. Implantation conditions and annealing conditions are detailed. The gage factor and its temperature variation are not drastically affected by crystal damage for some crystal orientations. A model is proposed to account for the effects of electron damage on the temperature dependence of resistivity and on silicon piezoresistance. The results are applicable to the design of silicon-on-sapphire strain gages with high gage factors.

  20. Temperature-induced unfolding of epidermal growth factor (EGF): insight from molecular dynamics simulation.

    PubMed

    Yan, Chunli; Pattani, Varun; Tunnell, James W; Ren, Pengyu

    2010-08-24

    Thermal disruption of protein structure and function is a potentially powerful therapeutic vehicle. With the emerging nanoparticle-targeting and femtosecond laser technology, it is possible to deliver heating locally to specific molecules. It is therefore important to understand how fast a protein can unfold or lose its function at high temperatures, such as near the water boiling point. In this study, the thermal damage of EGF was investigated by combining the replica exchange (136 replicas) and conventional molecular dynamics simulations. The REMD simulation was employed to rigorously explore the free-energy landscape of EGF unfolding. Interestingly, besides the native and unfolded states, we also observed a distinct molten globule (MG) state that retained substantial amount of native contacts. Based on the understanding that which the unfolding of EGF is a three-state process, we have examined the unfolding kinetics of EGF (N-->MG and MG-->D) with multiple 20-ns conventional MD simulations. The Arrhenius prefactors and activation energy barriers determined from the simulation are within the range of previously studied proteins. In contrast to the thermal damage of cells and tissues which take place on the time scale of seconds to hours at relatively low temperatures, the denaturation of proteins occur in nanoseconds when the temperature of heat bath approaches the boiling point. PMID:20466569

  1. 77 FR 72199 - Technical Corrections; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-05

    ...) is correcting a final rule that was published in the Federal Register on July 6, 2012 (77 FR 39899), and effective on August 6, 2012. That final rule amended the NRC regulations to make technical... COMMISSION 10 CFR Part 171 RIN 3150-AJ16 Technical Corrections; Correction AGENCY: Nuclear...

  2. Growth, condition factor, and bioenergetics modeling link warmer stream temperatures below a small dam to reduced performance of juvenile steelhead

    USGS Publications Warehouse

    Sauter, S.T.; Connolly, P.J.

    2010-01-01

    We investigated the growth and feeding performance of juvenile steelhead Oncorhynchus mykiss using field measures and bioenergetics modeling. Juvenile steelhead populations were sampled from mid-June through August 2004 at study sites upstream and downstream of Hemlock Dam. The growth and diet of juvenile steelhead were determined for a warm (summer) and subsequent (late summer) transitional period at each study site. Empirical data on the growth and diet of juvenile steelhead and mean daily temperatures were used in a bioenergetics model to estimate the proportion of maximum consumption achieved by juvenile steelhead by site and period. Modeled estimates of feeding performance were better for juvenile steelhead at the upstream compared to the downstream site during both periods. The median condition factor of juvenile steelhead did not change over the summer at the upstream site, but showed a significant decline over time at the downstream site. A negative trend in median condition factor at the downstream site supported bioenergetics modeling results that suggested the warmer stream temperatures had a negative impact on juvenile steelhead. Bioenergetics modeling predicted a lower feeding performance for juvenile steelhead rearing downstream compared to upstream of Hemlock Dam although food availability appeared to be limited at both study sites during the warm period. Warmer water temperatures, greater diel variation, and change in diel pattern likely led to the reduced feeding performance and reduced growth, which could have affected the overall survival of juvenile steelhead downstream of Hemlock Dam. ?? 2010 by the Northwest Scientific Association.

  3. The time of day differently influences fatigue and locomotor activity: is body temperature a key factor?

    PubMed

    Machado, Frederico Sander Mansur; Rodovalho, Gisele Vieira; Coimbra, Cândido Celso

    2015-03-01

    The aim of this study was to verify the possible interactions between exercise capacity and spontaneous locomotor activity (SLA) during the oscillation of core body temperature (Tb) that occurs during the light/dark cycle. Wistar rats (n=11) were kept at an animal facility under a light/dark cycle of 14/10h at an ambient temperature of 23°C and water and food ad libitum. Initially, in order to characterize the daily oscillation in SLA and Tb of the rats, these parameters were continuously recorded for 24h using an implantable telemetric sensor (G2 E-Mitter). The animals were randomly assigned to two progressive exercise test protocols until fatigue during the beginning of light and dark-phases. Fatigue was defined as the moment rats could not keep pace with the treadmill. We assessed the time to fatigue, workload and Tb changes induced by exercise. Each test was separated by 3days. Our results showed that exercise capacity and heat storage were higher during the light-phase (p<0.05). In contrast, we observed that both SLA and Tb were higher during the dark-phase (p<0.01). Notably, the correlation analysis between the amount of SLA and the running capacity observed at each phase of the daily cycle revealed that, regardless of the time of the day, both types of locomotor physical activity have an important inherent component (r=0.864 and r=0.784, respectively, p<0.01) without a direct relationship between them. This finding provides further support for the existence of specific control mechanisms for each type of physical activity. In conclusion, our data indicate that the relationship between the body temperature and different types of physical activity might be affected by the light/dark cycle. These results mean that, although exercise performance and spontaneous locomotor activity are not directly associated, both are strongly influenced by daily cycles of light and dark. PMID:25479573

  4. Microstructural factors influencing critical-current densities of high-temperature superconductors

    SciTech Connect

    Suenaga, M.

    1992-01-01

    Microstructural defects are the primary determining factors for the values of critical current densities in superconductors. A review is made to assess, (1) what would be the maximum achievable critical-current density in the oxide superconductors if nearly ideal pinning sites were introduced and (2) what types of pinning defects are currently introduced in these superconductors and how effective are these in pinning the vortices Only the case where the applied field is parallel to the c-axis is considered here.

  5. Microstructural factors influencing critical-current densities of high-temperature superconductors

    SciTech Connect

    Suenaga, M.

    1992-12-31

    Microstructural defects are the primary determining factors for the values of critical current densities in superconductors. A review is made to assess, (1) what would be the maximum achievable critical-current density in the oxide superconductors if nearly ideal pinning sites were introduced? and (2) what types of pinning defects are currently introduced in these superconductors and how effective are these in pinning the vortices? Only the case where the applied field is parallel to the c-axis is considered here.

  6. Escape factors for Paschen 2p–1s emission lines in low-temperature Ar, Kr, and Xe plasmas

    NASA Astrophysics Data System (ADS)

    Zhu, Xi-Ming; Cheng, Zhi-Wen; Pu, Yi-Kang; Czarnetzki, Uwe

    2016-06-01

    Radiation trapping phenomenon is often observed when investigating low-temperature plasmas. Photons emitted from the upper excited states may be reabsorbed by the lower states before they leave the plasmas. In order to account for this effect in the modelling and optical diagnostics of plasmas, either an ‘escape factor’ of a function of the optical depth or a strict solution of the radiation transfer equation can be employed. However, the former is more convenient in comparison and thus is widely adopted. Previous literatures have provided several simple expressions of the escape factor for the uniform plasmas. The emission line profiles are assumed to be dominated by the Doppler broadening, and the line splitting due to the hyperfine structure is not considered. This kind of expression is only valid for small atoms, e.g. Ar in low-pressure uniform discharges. Actually, the excited state density in many of the low-temperature plasmas is non-uniform and the emission line profile can be significantly influenced by the collisional broadening at medium and high pressures. In these cases, a new escape factor equation should be calculated. In this work, we study the escape factor equations for the often used 2p–1s transitions (Paschen’s notation) of the Ar, Kr, and Xe atoms. Possible non-uniform density profiles are considered. In addition, we include the line splitting due to the hyperfine structure for Kr and Xe. For the low-pressure plasmas, an escape factor expression mainly based on the Gaussian line profile is given and particularly verified by an experiment in a low-pressure capacitive discharge. For the high-pressure plasmas, an equation based on the Voigt line profile is also calculated. In this way, the new escape factor expression is ready for use in the modelling of the Ar, Kr, and Xe plasmas from low to atmospheric pressure.

  7. Escape factors for Paschen 2p-1s emission lines in low-temperature Ar, Kr, and Xe plasmas

    NASA Astrophysics Data System (ADS)

    Zhu, Xi-Ming; Cheng, Zhi-Wen; Pu, Yi-Kang; Czarnetzki, Uwe

    2016-06-01

    Radiation trapping phenomenon is often observed when investigating low-temperature plasmas. Photons emitted from the upper excited states may be reabsorbed by the lower states before they leave the plasmas. In order to account for this effect in the modelling and optical diagnostics of plasmas, either an ‘escape factor’ of a function of the optical depth or a strict solution of the radiation transfer equation can be employed. However, the former is more convenient in comparison and thus is widely adopted. Previous literatures have provided several simple expressions of the escape factor for the uniform plasmas. The emission line profiles are assumed to be dominated by the Doppler broadening, and the line splitting due to the hyperfine structure is not considered. This kind of expression is only valid for small atoms, e.g. Ar in low-pressure uniform discharges. Actually, the excited state density in many of the low-temperature plasmas is non-uniform and the emission line profile can be significantly influenced by the collisional broadening at medium and high pressures. In these cases, a new escape factor equation should be calculated. In this work, we study the escape factor equations for the often used 2p-1s transitions (Paschen’s notation) of the Ar, Kr, and Xe atoms. Possible non-uniform density profiles are considered. In addition, we include the line splitting due to the hyperfine structure for Kr and Xe. For the low-pressure plasmas, an escape factor expression mainly based on the Gaussian line profile is given and particularly verified by an experiment in a low-pressure capacitive discharge. For the high-pressure plasmas, an equation based on the Voigt line profile is also calculated. In this way, the new escape factor expression is ready for use in the modelling of the Ar, Kr, and Xe plasmas from low to atmospheric pressure.

  8. Factors influencing the upper temperature tolerances of three mussel species in a brackish water canal: size, season and laboratory protocols.

    PubMed

    Rajagopal, S; van der Velde, G; van der Gaag, M; Jenner, H A

    2005-01-01

    Mussels are the most problematic organisms encountered in the water intake systems of electrical power plants. Various fouling control measures are adopted, among which heat treatment is considered the relatively more attractive from economic and ecological points of view. Thermal tolerance experiments were carried out to determine the effects of mussel size (2-20 mm shell length), season (breeding vs non-breeding), nutritional status (fed vs non-fed), acclimation temperature (5-25 degrees C) and acclimation salinity (1-35%o) on the mortality pattern of three important mussel species, viz. a freshwater mussel Dreissena polymorpha, a brackish water mussel Mytilopsis leucophaeata and a marine mussel Mytilus edulis under different temperatures (36-41 degrees C). The mussels in the 10 mm size group exposed to 36 degrees C showed 100% mortality after 38 min (D. polymorpha), 84 min (M. edulis) and 213 min (M. leucophaeata). The effect of mussel size on M. edulis and M. leucophaeata mortality at different temperatures was significant, with the largest size group of mussels showing greater resistance, while no significant size-dependence was observed in the case of D. polymorpha. All the three mussel species collected during the non-breeding season (June-October). Nutritional status had no significant influence on the thermal tolerance of the three mussels; fed and non-fed mussels showed 100% mortality at comparable rates. Acclimation temperature had a significant effect on the mortality of all three species. Survival time at any given target temperature increased with increasing acclimation temperature. The acclimation salinity showed no significant effect on the thermal tolerance of the three mussel species. In comparison, M. leucophaeata was more tolerant to high temperature stress than the other two species. The present studies clearly show that various factors can influence the mortality of D. polymorpha, M. edulis and M. leucophaeata to elevated temperatures. The

  9. Transcriptome-based discovery of AP2/ERF transcription factors related to temperature stress in tea plant (Camellia sinensis).

    PubMed

    Wu, Zhi-Jun; Li, Xing-Hui; Liu, Zhi-Wei; Li, Hui; Wang, Yong-Xin; Zhuang, Jing

    2015-11-01

    Tea plant (Camellia sinensis) is an important natural resource for the global supply of non-alcoholic beverage production. The extension of tea plant cultivation is challenged by biotic and abiotic stresses. Transcription factors (TFs) of the APETALA 2 (AP2)/ethylene-responsive factor (ERF) family are involved in growth and anti-stresses through multifaceted transcriptional regulation in plants. This study comprehensively analyzed AP2/ERF family TFs from C. sinensis on the basis of the transcriptome sequencing data of four tea plant cultivars, namely, 'Yunnanshilixiang', 'Chawansanhao', 'Ruchengmaoyecha', and 'Anjibaicha'. A total of 89 putative AP2/ERF transcription factors with full-length AP2 domain were identified from C. sinensis and classified into five subfamilies, namely, AP2, dehydration-responsive-element-binding (DREB), ERF, related to ABI3/VP (RAV), and Soloist. All identified CsAP2/ERF genes presented relatively stable expression levels in the four tea plant cultivars. Many groups also showed cultivar specificity. Five CsAP2/ERF genes from each AP2/ERF subfamily (DREB, ERF, AP2, and RAV) were related to temperature stresses; these results indicated that AP2/ERF TFs may play important roles in abnormal temperature stress response in C. sinensis.

  10. Changes in Cry1Ac Bt transgenic cotton in response to two environmental factors: temperature and insect damage.

    PubMed

    Olsen, K M; Daly, J C; Finnegan, E J; Mahon, R J

    2005-08-01

    The efficacy of Cry1Ac Bacillus thuringiensis (Bt) cotton plants against field populations of Helicoverpa armigera (Hübner) has been inconsistent over the growing season. Any reduction in efficacy (where efficacy is the capacity of the plant to affect the survival of the insect) increases the opportunities for H. armigera to evolve resistance to Bt toxin. Changes in efficacy could be due to changes at the level of gene expression and/or in the physiological makeup of the plant and may be induced by environmental conditions. Two environmental factors, temperature and insect damage, were investigated. Temperature was found to affect efficacy, whether plants were grown at different temperatures continuously or were exposed to a change in temperature for a short period. Damage caused by chewing insects (H. armigera larvae) produced a dramatic increase in the efficacy of presquare Bt cotton. In contrast, damage by sucking insects (aphids) did not induce changes in efficacy. Changes in efficacy seemed to be mediated through modification of the physiological background of the plant rather than changes in the level of Cry1Ac expression or in the concentration of the Bt toxin. The impact of the non-Bt responses of plants on strains of H. armigera should be evaluated. It is possible that by enhancing existing defensive mechanisms of plants, the rate of evolution of resistance to Bt toxins could be retarded by increasing the plants overall toxicity through the additive effects of the toxins and plant defenses.

  11. Single-crystal sapphire resonator at millikelvin temperatures: Observation of thermal bistability in high-Q factor whispering gallery modes

    SciTech Connect

    Creedon, Daniel L.; Tobar, Michael E.; Le Floch, Jean-Michel; Reshitnyk, Yarema; Duty, Timothy

    2010-09-01

    Resonance modes in single crystal sapphire ({alpha}-Al{sub 2}O{sub 3}) exhibit extremely high electrical and mechanical Q factors ({approx_equal}10{sup 9} at 4 K), which are important characteristics for electromechanical experiments at the quantum limit. We report the cool down of a bulk sapphire sample below superfluid liquid-helium temperature (1.6 K) to as low as 25 mK. The electromagnetic properties were characterized at microwave frequencies, and we report the observation of electromagnetically induced thermal bistability in whispering gallery modes due to the material T{sup 3} dependence on thermal conductivity and the ultralow dielectric loss tangent. We identify ''magic temperatures'' between 80 and 2100 mK, the lowest ever measured, at which the onset of bistability is suppressed and the frequency-temperature dependence is annulled. These phenomena at low temperatures make sapphire suitable for quantum metrology and ultrastable clock applications, including the possible realization of the quantum-limited sapphire clock.

  12. Corrective Jaw Surgery

    MedlinePlus

    ... and Craniofacial Surgery Cleft Lip/Palate and Craniofacial Surgery A cleft lip may require one or more ... find out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment ...

  13. Study of Inactivation Factors in Low Temperature Surface-wave Plasma Sterilization

    NASA Astrophysics Data System (ADS)

    Singh, Mrityunjai Kumar; Xu, Lei; Ogino, Akihisa; Nagatsu, Masaaki

    In this study we investigated the low temperature surface-wave plasma sterilization of directly and indirectly exposed Geobacillus stearothermophilus spores with a large-volume microwave plasma device. The air-simulated gas mixture was used to produce the plasma. The water vapor addition to the gas mixture improved the sterilization efficiency significantly. The effect of ultraviolet photons produced along with plasma to inactivate the spores was studied using a separate chamber, which was evacuated to less than one mTorr and was observed that spores were sterilized within 60 min. The scanning electron microscopy images revealed no significant changes in the actual size of the spores with that of untreated spores despite the survival curve shown that the spores were inactivated.

  14. Light, temperature and nutrients as factors in photosynthetic adjustment to elevated carbon dioxide

    SciTech Connect

    Bunce, J.; Lee, D. )

    1991-05-01

    It has been noted many times that the short-term stimulation of photosynthesis by elevated carbon dioxide usually observed in C3 plants may not persist in the long-term. Experiments were designed to test the hypotheses that photosynthetic adjustment to elevated carbon dioxide is due to (a) feedback inhibition resulting from excess photosynthate production relative to use, and (b) nutrient deficiency resulting from more rapid growth. Soybeans and sugarbeets were grown in controlled environment chambers at 350 and 700 ppm carbon dioxide, at two temperatures, two levels of photosynthetically active radiation, and with three nutrient regimes in a factorial design. Net carbon dioxide uptake rates of individual leaves from all growth conditions were measured at both 350 and 700 ppm carbon dioxide to assay photosynthetic adjustment to the elevated carbon dioxide. Growth at elevated carbon dioxide reduced rates of photosynthesis measured at standard carbon dioxide levels in both species. Photosynthetic rates measured at 350 ppm were lower on average by 33% in sugarbeet and 23% in soybean after growth at elevated carbon dioxide. Photosynthetic adjustment to elevated carbon dioxide was not greater after growth at 1.0 than 0.5 mmol m{sup {minus}2}s{sup {minus}1} PPFD, was not greater at 20 than 25C growth temperature, and could not be overcome by high rates of nutrient application. These results do not support either the feedback inhibition nor nutrient deficiency hypotheses of photosynthetic adjustment to elevated carbon dioxide. In soybeans, complete photosynthetic adjustment could be induced by a single night at elevated carbon dioxide.

  15. Stress, temperature, heart rate, and hibernating factors in hamsters. [pathophysiological conditions resulting from exposure to zero gravity

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.

    1974-01-01

    Pathophysiological conditions resulting from prolonged exposure to zero gravity, cabin constraint, altered ambient environment, whether it be noise, vibrations, high temperatures, or combinations of such factors, are studied in laboratory animals and applied to manned space flight. Results and plans for further study are presented. Specific topics covered include: thermoregulation and its role in reflecting stress and adaptation to the gravity free environment and cabin confinement with its altered circadian forcings; renal function and its measurement in electrolyte distribution and blood flow dynamics; gastronintestinal function and an assessment of altered absorptive capacity in the intestinal mucosa; and catecholamine metabolism in terms of distribution and turnover rates in specific tissues.

  16. Factors influencing the formation of histaminol, hydroxytyrosol, tyrosol, and tryptophol in wine: Temperature, alcoholic degree, and amino acids concentration.

    PubMed

    Bordiga, M; Lorenzo, C; Pardo, F; Salinas, M R; Travaglia, F; Arlorio, M; Coïsson, J D; Garde-Cerdán, T

    2016-04-15

    The validation of a HPLC-PDA-MS/MS chromatographic method for the quali/quantitative characterization of histaminol, hydroxytyrosol, tyrosol, and tryptophol in wine has been described and discussed. Four standards showed a good linearity with high correlation coefficient values (over 0.9989) and LOD and LOQ were 0.001-0.015 mg/L and 0.004-0.045 mg/L, respectively. Furthermore, this study reported how factors such as temperature, alcoholic degree, and amino acids concentration are able to influence the formation of these four alcohols in Monastrell wines. The quantification values of these alcohols has been detected both at the half and end of alcoholic fermentation, and at the end of malolactic fermentation. In relation to interactions between factors, several significant variations emerged (p ⩽ 0.001). The impact of amino acids supplementation in Monastrell must it has been demonstrated, mainly in regards to histaminol and tryptophol. PMID:26675839

  17. Detector signal correction method and system

    DOEpatents

    Carangelo, Robert M.; Duran, Andrew J.; Kudman, Irwin

    1995-07-11

    Corrective factors are applied so as to remove anomalous features from the signal generated by a photoconductive detector, and to thereby render the output signal highly linear with respect to the energy of incident, time-varying radiation. The corrective factors may be applied through the use of either digital electronic data processing means or analog circuitry, or through a combination of those effects.

  18. Efficacy of a unique omega-3 formulation on the correction of nutritional deficiency and its effects on cardiovascular disease risk factors in a randomized controlled VASCAZEN(®) REVEAL Trial.

    PubMed

    Shaikh, Nisar A; Yantha, Jason; Shaikh, Sabah; Rowe, William; Laidlaw, Maggie; Cockerline, Carla; Ali, Abbas; Holub, Bruce; Jackowski, George

    2014-11-01

    Low blood levels of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) have been reported to be associated with increased risk for cardiovascular disease (CVD) deaths. Systematic studies measuring LC n-3 PUFA blood levels (pre and post-treatment) in defined subjects, and monitoring the correction of nutritional deficiency with a pure LC n-3 PUFA formulation in sufficient doses, while monitoring CVD risk factors are lacking. We tested the efficacy of a novel LC n-3 PUFA Medical Food formulation (VASCAZEN(®), > 90 % pure with a 6:1 eicosapentaenoic acid-(EPA):docosahexaenoic acid-(DHA) ratio; 6:1-OM3), to correct such deficiency and determine the concomitant effects on lipid profiles. Of 655 subjects screened, 89 % were LC n-3 PUFA deficient (Omega-Score, (OS) = blood EPA + DHA + Docosapentaenoic acid < 6.1 %). From these, a study was conducted on 110 ambulatory cardiovascular subjects. Placebo: corn oil. Primary endpoint: change in OS. Secondary endpoint: changes in blood lipid profiles. At 8 weeks of treatment with 6:1-OM3 (4 g/day), placebo-adjusted median OS levels (n = 56) significantly improved (132 %, P < 0.0001) with a decrease in AA (arachidonic acid): EPA ratio (82 %, P < 0.0001). In hypertriglyceridemic subjects (TG 2.26-5.65 mmol/L), HDL-C improved (9 %, P = 0.0069), TG-reduced (48 %, P < 0.0001), and VLDL-C reduced (30 %, P = 0.0023), without significantly affecting LDL-C levels. This study confirms that LC n-3 PUFA deficiency is prevalent in the US population, and its correction with 6:1-OM3 in CVD subjects improves lipid profiles. The purity, EPA:DHA ratio and dose are determinant factors for optimal efficacy of a formulation in reducing CVD risk factors.

  19. [Errors Analysis and Correction in Atmospheric Methane Retrieval Based on Greenhouse Gases Observing Satellite Data].

    PubMed

    Bu, Ting-ting; Wang, Xian-hua; Ye, Han-han; Jiang, Xin-hua

    2016-01-01

    High precision retrieval of atmospheric CH4 is influenced by a variety of factors. The uncertainties of ground properties and atmospheric conditions are important factors, such as surface reflectance, temperature profile, humidity profile and pressure profile. Surface reflectance is affected by many factors so that it is difficult to get the precise value. The uncertainty of surface reflectance will cause large error to retrieval result. The uncertainties of temperature profile, humidity profile and pressure profile are also important sources of retrieval error and they will cause unavoidable systematic error. This error is hard to eliminate only using CH4 band. In this paper, ratio spectrometry method and CO2 band correction method are proposed to reduce the error caused by these factors. Ratio spectrometry method can decrease the effect of surface reflectance in CH4 retrieval by converting absolute radiance spectrometry into ratio spectrometry. CO2 band correction method converts column amounts of CH4 into column averaged mixing ratio by using CO2 1.61 μm band and it can correct the systematic error caused by temperature profile, humidity profile and pressure profile. The combination of these two correction methods will decrease the effect caused by surface reflectance, temperature profile, humidity profile and pressure profile at the same time and reduce the retrieval error. GOSAT data were used to retrieve atmospheric CH4 to test and validate the two correction methods. The results showed that CH4 column averaged mixing ratio retrieved after correction was close to GOSAT Level2 product and the retrieval precision was up to -0.24%. The studies suggest that the error of CH4 retrieval caused by the uncertainties of ground properties and atmospheric conditions can be significantly reduced and the retrieval precision can be highly improved by using ratio spectrometry method and CO2 hand correction method.

  20. [Errors Analysis and Correction in Atmospheric Methane Retrieval Based on Greenhouse Gases Observing Satellite Data].

    PubMed

    Bu, Ting-ting; Wang, Xian-hua; Ye, Han-han; Jiang, Xin-hua

    2016-01-01

    High precision retrieval of atmospheric CH4 is influenced by a variety of factors. The uncertainties of ground properties and atmospheric conditions are important factors, such as surface reflectance, temperature profile, humidity profile and pressure profile. Surface reflectance is affected by many factors so that it is difficult to get the precise value. The uncertainty of surface reflectance will cause large error to retrieval result. The uncertainties of temperature profile, humidity profile and pressure profile are also important sources of retrieval error and they will cause unavoidable systematic error. This error is hard to eliminate only using CH4 band. In this paper, ratio spectrometry method and CO2 band correction method are proposed to reduce the error caused by these factors. Ratio spectrometry method can decrease the effect of surface reflectance in CH4 retrieval by converting absolute radiance spectrometry into ratio spectrometry. CO2 band correction method converts column amounts of CH4 into column averaged mixing ratio by using CO2 1.61 μm band and it can correct the systematic error caused by temperature profile, humidity profile and pressure profile. The combination of these two correction methods will decrease the effect caused by surface reflectance, temperature profile, humidity profile and pressure profile at the same time and reduce the retrieval error. GOSAT data were used to retrieve atmospheric CH4 to test and validate the two correction methods. The results showed that CH4 column averaged mixing ratio retrieved after correction was close to GOSAT Level2 product and the retrieval precision was up to -0.24%. The studies suggest that the error of CH4 retrieval caused by the uncertainties of ground properties and atmospheric conditions can be significantly reduced and the retrieval precision can be highly improved by using ratio spectrometry method and CO2 hand correction method. PMID:27228765

  1. An Exploratory Investigation of Some Factors Influencing the Room-Temperature Ductility of Tungsten

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.

    1960-01-01

    Specimens having an initial diameter of 0.125 inch were cut from commercially pure sintered and swaged tungsten rods. The effect of various surface treatments on the ductility of tungsten was evaluated by the use of a bend test. The criterion used to determine the relative ductilities was the final bend angle of the specimens. Results showed that the bend ductility of the tungsten specimens increased with increasing depths of the surface removed by electropolishing. When specimens electropolished to a depth sufficient to produce a marked increase in the ductility over that of the as-received surface condition were subsequently scratched with emery paper, the ductility achieved by electropolishing was greatly reduced. Removal of similar depths of the surface by grinding as were removed by electropolishing did not produce any appreciable increase in the ductility of the specimens. The ductility of specimens tested in the as-received surface condition and those having an electropolished surface exhibited a great sensitivity to deflection rate, the electropolished specimens being more ductile over the range of deflection rates tested. These exploratory results illustrated qualitatively the importance of surface condition on the room-temperature ductility of tungsten and indicated the importance of relatively fine scratches on the ductility of tungsten.

  2. Regression analysis in modeling of air surface temperature and factors affecting its value in Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Rajab, Jasim Mohammed; Jafri, Mohd. Zubir Mat; Lim, Hwee San; Abdullah, Khiruddin

    2012-10-01

    This study encompasses air surface temperature (AST) modeling in the lower atmosphere. Data of four atmosphere pollutant gases (CO, O3, CH4, and H2O) dataset, retrieved from the National Aeronautics and Space Administration Atmospheric Infrared Sounder (AIRS), from 2003 to 2008 was employed to develop a model to predict AST value in the Malaysian peninsula using the multiple regression method. For the entire period, the pollutants were highly correlated (R=0.821) with predicted AST. Comparisons among five stations in 2009 showed close agreement between the predicted AST and the observed AST from AIRS, especially in the southwest monsoon (SWM) season, within 1.3 K, and for in situ data, within 1 to 2 K. The validation results of AST with AST from AIRS showed high correlation coefficient (R=0.845 to 0.918), indicating the model's efficiency and accuracy. Statistical analysis in terms of β showed that H2O (0.565 to 1.746) tended to contribute significantly to high AST values during the northeast monsoon season. Generally, these results clearly indicate the advantage of using the satellite AIRS data and a correlation analysis study to investigate the impact of atmospheric greenhouse gases on AST over the Malaysian peninsula. A model was developed that is capable of retrieving the Malaysian peninsulan AST in all weather conditions, with total uncertainties ranging between 1 and 2 K.

  3. Exercise hyperthermia as a factor limiting physical performance - Temperature effect on muscle metabolism

    NASA Technical Reports Server (NTRS)

    Kozlowski, S.; Brzezinska, Z.; Kruk, B.; Kaciuba-Uscilko, H.; Greenleaf, J. E.

    1985-01-01

    The effect of trunk cooling on the muscle contents of ATP, ADP, AMP, creatine phosphate (CrP), and creatine, as well as of glycogen, some glycolytic intermediates, pyruvate, and lactate were assessed in 11 fasted dogs exercised at 20 C on treadmill to exhaustion. Without cooling, dogs were able to run 57 min, and their rectal (Tre) and muscle (Tm) temperatures increased to 41.8 and 43.0 C, respectively. Cooling with ice packs prolonged the ability to run by 45 percent, and resulted in lower Tre (by 1.1 C) and Tm (by 1.2 C). Depletion of muscle content of total high-energy phosphates (ATP + CrP) and glycogen, and increases in contents of AMP, pyruvate, and lactate were lower in cooled dogs than in non-cooled dogs. The muscle content of lactiate correlated positively with TM. These results indicate that hypothermia accelerates glycolysis, and shifts the equilibrium between high- and low-energy phosphates in favor of the latter. The adverse effect of hypothermia on muscle metabolism may be relevant to the limitation of endurance.

  4. Temperature and angiogenesis: the possible role of mechanical factors in capillary growth.

    PubMed

    Egginton, Stuart

    2002-08-01

    This review examines the effect of prolonged cold exposure on muscle capillary supply in mammals and fishes. In rats and hamsters, the response to a simulated onset of winter is to conserve the microcirculation and maintain a constant capillary to fibre ratio (C:F), implying either an unaltered vacular bed or angiogenesis matched by muscle hyperplasia, while chronic acclimation to low environmental temperature induces a variable degree of muscle atrophy, which in turn increases capillary density (CD). In striped bass and rainbow trout, cold-induced angiogenesis results in an increase in C:F, but also a cold-induced fibre hypertrophy that is accompanied by a powerful angiogenic response such that CD is much less sensitive to changes in fibre size. Endothelial cells can act as mechanotransducers such that angiogenesis may be initiated by changes in their physical environment. It is hypothesised that in mammals, the metabolic consequences of cold exposure increases the luminal shear stress, while in fishes the stimulus for angiogenesis is abluminal stretch following an increase in fibre size.

  5. Factors regulating soil surface CO2 and NOx flux in response to high temperature, pulse water events, and nutrient fertilization

    NASA Astrophysics Data System (ADS)

    Oikawa, P. Y.; Grantz, D. A.; Chatterjee, A.; Eberwein, J. R.; Allsman, L. A.; Jenerette, D.

    2012-12-01

    Trace gas emissions from the soil surface are often underestimated due to poor understanding of the factors regulating fluxes under extreme conditions when moisture can be highly variable. In particular, dynamics of soil surface trace gas emissions from hot agricultural regions can be difficult to predict due to the sporadic use of flood irrigation and nitrogen fertilization. Soil surface CO2 and NOx fluxes are especially difficult to predict due to nonlinear responses to pulse water and fertilization events. Additionally, models such as Lloyd and Taylor (1994) and Yienger and Levy II (1995) are not well parameterized for soil surface CO2 and NOx flux, respectively, under excessively high temperatures. We measured soil surface CO2 and NOx flux in an agricultural field transitioning from fallow to biofuel crop production (Sorghum bicolor). Soil surface CO2 flux was measured using CO2 probes coupled with the flux-gradient method. NOx measurements were made using chambers coupled with a NOx monitor. Our field site is located at the University of California Desert Research and Extension Center in the Imperial Valley of CA. Air temperatures regularly exceed 42°C in the summer. Flood irrigation is used at the site as well as nitrogen fertilizers. Soil respiration ranged from 0-15 μmoles CO2 m-2 s-1, with strong hysteresis observed both with and without plants. Soil CO2 fluxes measured in the fallow field before the biofuel crop was planted were temperature independent and mainly regulated by soil moisture. When plants were introduced, temperature became an important predictor for soil respiration as well as canopy height. NOx fluxes were highest at intermediate soil moisture and varied significantly across an irrigation cycle. NOx emissions were temperature dependent, ranging from 3-113 ng N cm-2 hr-1. Neither CO2 nor NOx emissions showed inhibition at soil temperatures up to 55°C. Models may underestimate fluxes of CO2 and NOx from hot agricultural regions due to

  6. Current-oscillator correlation and Fano factor spectrum of quantum shuttle with finite bias voltage and temperature.

    PubMed

    Lai, Wenxi; Cao, Yunshan; Ma, Zhongshui

    2012-05-01

    A general master equation is derived to describe an electromechanical single-dot transistor in the Coulomb blockade regime. In the equation, Fermi distribution functions in the two leads are taken into account, which allows one to study the system as a function of bias voltage and temperature of the leads. Furthermore, we treat the coherent interaction mechanism between electron tunneling events and the dynamics of excited vibrational modes. Stationary solutions of the equation are numerically calculated. We show that current through the oscillating island at low temperature appears to have step-like characteristics as a function of the bias voltage and the steps depend on the mean phonon number of the oscillator. At higher temperatures the current steps would disappear and this event is accompanied by the emergence of thermal noise of the charge transfer. When the system is mainly in the ground state, the zero frequency Fano factor of current manifests sub-Poissonian noise and when the system is partially driven into its excited states it exhibits super-Poissonian noise. The difference in the current noise would almost be removed for the situation in which the dissipation rate of the oscillator is much larger than the bare tunneling rates of electrons.

  7. Factors affecting the wettability of different surface materials with vegetable oil at high temperatures and its relation to cleanability

    NASA Astrophysics Data System (ADS)

    Ashokkumar, Saranya; Adler-Nissen, Jens; Møller, Per

    2012-12-01

    The main aim of the work was to investigate the wettability of different surface materials with vegetable oil (olive oil) over the temperature range of 25-200 °C to understand the differences in cleanability of different surfaces exposed to high temperatures in food processes. The different surface materials investigated include stainless steel (reference), PTFE (polytetrafluoroethylene), silicone, quasicrystalline (Al, Fe, Cr) and ceramic coatings: zirconium oxide (ZrO2), zirconium nitride (ZrN) and titanium aluminum nitride (TiAlN). The ceramic coatings were deposited on stainless steel with two different levels of roughness. The cosine of the contact angle of olive oil on different surface materials rises linearly with increasing temperature. Among the materials analyzed, polymers (PTFE, silicone) gave the lowest cos θ values. Studies of the effect of roughness and surface flaws on wettability revealed that the cos θ values increases with increasing roughness and surface flaws. Correlation analysis indicates that the measured contact angle values gave useful information for grouping easy-clean polymer materials from the other materials; for the latter group, there is no direct relation between contact angle and cleanability. In addition to surface wettability with oil many other factors such as roughness and surface defects play an essential role in determining their cleanability.

  8. Neutron Scattering Facility for the Measurement of Light Quenching Factors of Dark Matter Detectors at Low Temperatures

    NASA Astrophysics Data System (ADS)

    Strauss, R.; Ciemniak, C.; Deuter, G.; von Feilitzsch, F.; Gütlein, A.; Hagn, H.; Jochum, J.; Lanfranchi, J.-C.; Lepelmeier, J.; Pfister, S.; Potzel, W.; Roth, S.; Rottler, K.; Sailer, C.; Scholl, S.; von Sivers, M.; Thalhammer, U.; Wawoczny, S.; Willers, M.; Usherov, I.

    2012-06-01

    The light yield of scintillating crystals which is quantified by light Quenching Factors (QFs) strongly depends on the kind of interaction in the crystal. For Dark Matter experiments like CRESST the precise knowledge of QFs is crucial for the discrimination of background events from possible WIMP signals. At the tandem accelerator of the Maier-Leibnitz-Laboratorium (MLL) in Garching a low-temperature scattering facility was set up, which in its current phase aims at the determination of the QFs of O, Ca, and W in CaWO4 crystals as used in the CRESST experiment. A CRESST detector module consists of a 300 g CaWO4 target crystal operated as a phonon detector and a separate silicon-on-sapphire (SOS) light detector to detect the corresponding scintillation light simultaneously. In order to disentangle the light yield corresponding to O, Ca and W recoils, monoenergetic neutrons (11 MeV) produced by the accelerator are scattered off an especially developed CRESST-like detector module, which is operated at mK temperatures in a dilution refrigerator. Arrays of liquid-scintillator detectors placed at fixed scattering angles allow one to identify the recoiling nuclei by a neutron time-of-flight measurement. The unique facility is suited for the characterization of different detector materials and will be a powerful tool also for the future multi-material experiment EURECA. We report on the experimental approach, the low-temperature setup and present first results.

  9. Effect of gray-body interchange factor and radiating temperature on the thermal response of the DT-18 shipping container

    SciTech Connect

    Anderson, J.C.; Feldman, M.R.

    1992-02-01

    Some concerns and questions have been raised regarding the values of the DT-18 package surface emissivity, the emissivity of the B-1023 furnace used for thermal testing of DOE shipping packages, and the furnace radiating temperature that should be employed during thermal tests. In order for the thermal tests performed at the Y-12 Plan in Oak Ridge, Tennessee, to comply with the regulations specified in 10 CFR 71, it must be shown that a specific amount of heat is added to the package during the test. Therefore, a method of thermal analytical modeling was developed to calculate the quantity of heat energy input to which a DT-18 package is exposed during hypothetical accident scenario testing. Parametric studies involving the gray-body interchange factor (which embodies both the package and furnace emissivities) and the furnace radiating temperature were then performed, and the effects of these two variables on the net total heat received by a DT-18 package were determined. Based on the analyses presented in this report, simple guidelines and recommendations are made to order to ensure that thermal testing in the B-1023 furnace complies with federal regulations. Data are presented which allow the determination of an appropriate furnace surface temperature (800--850{degrees}C) based on the value of the gray-body interchange factor. The second alternative to ensure regulatory compliance involves allowing the DT-18 package to remain in the 800{degrees}C furnace for an additional amount of time (determined from presented data) beyond the required 30-min period.

  10. Thermoelectric Corrections to Quantum Measurement

    NASA Astrophysics Data System (ADS)

    Bergfield, Justin; Ratner, Mark; Stafford, Charles; di Ventra, Massimiliano

    The voltage and temperature measured by a floating probe of a nonequilibrium quantum system is shown to exhibit nontrivial thermoelectric corrections at finite temperature. Using a realistic model of a scanning thermal microscope to calculate the voltage and temperature distributions, we predict quantum temperature variations along graphene nanoribbons subject to a thermal bias which are not simply related to the local density of states. Experimentally, the wavelength of the oscillations can be tuned over several orders of magnitude by gating/doping, bringing quantum temperature oscillations within reach of the spatial resolution of existing measurement techniques. We also find that the Peltier cooling/heating which causes the temperature oscillations can lead to significant errors in voltage measurements for a wide range of system.

  11. Toward accurate thermochemistry of the {sup 24}MgH, {sup 25}MgH, and {sup 26}MgH molecules at elevated temperatures: Corrections due to unbound states

    SciTech Connect

    Szidarovszky, Tamás; Császár, Attila G.

    2015-01-07

    The total partition functions Q(T) and their first two moments Q{sup ′}(T) and Q{sup ″}(T), together with the isobaric heat capacities C{sub p}(T), are computed a priori for three major MgH isotopologues on the temperature range of T = 100–3000 K using the recent highly accurate potential energy curve, spin-rotation, and non-adiabatic correction functions of Henderson et al. [J. Phys. Chem. A 117, 13373 (2013)]. Nuclear motion computations are carried out on the ground electronic state to determine the (ro)vibrational energy levels and the scattering phase shifts. The effect of resonance states is found to be significant above about 1000 K and it increases with temperature. Even very short-lived states, due to their relatively large number, have significant contributions to Q(T) at elevated temperatures. The contribution of scattering states is around one fourth of that of resonance states but opposite in sign. Uncertainty estimates are given for the possible error sources, suggesting that all computed thermochemical properties have an accuracy better than 0.005% up to 1200 K. Between 1200 and 2500 K, the uncertainties can rise to around 0.1%, while between 2500 K and 3000 K, a further increase to 0.5% might be observed for Q{sup ″}(T) and C{sub p}(T), principally due to the neglect of excited electronic states. The accurate thermochemical data determined are presented in the supplementary material for the three isotopologues of {sup 24}MgH, {sup 25}MgH, and {sup 26}MgH at 1 K increments. These data, which differ significantly from older standard data, should prove useful for astronomical models incorporating thermodynamic properties of these species.

  12. Factors Influencing Oral Corrective Feedback Provision in the Spanish Foreign Language Classroom: Investigating Instructor Native/Nonnative Speaker Status, SLA Education, & Teaching Experience

    ERIC Educational Resources Information Center

    Gurzynski-Weiss, Laura

    2010-01-01

    The role of interactional feedback has been a critical area of second language acquisition (SLA) research for decades and while findings suggest interactional feedback can facilitate SLA, the extent of its influence can vary depending on a number of factors, including the native language of those involved in communication. Although studies have…

  13. Smooth eigenvalue correction

    NASA Astrophysics Data System (ADS)

    Hendrikse, Anne; Veldhuis, Raymond; Spreeuwers, Luuk

    2013-12-01

    Second-order statistics play an important role in data modeling. Nowadays, there is a tendency toward measuring more signals with higher resolution (e.g., high-resolution video), causing a rapid increase of dimensionality of the measured samples, while the number of samples remains more or less the same. As a result the eigenvalue estimates are significantly biased as described by the Marčenko Pastur equation for the limit of both the number of samples and their dimensionality going to infinity. By introducing a smoothness factor, we show that the Marčenko Pastur equation can be used in practical situations where both the number of samples and their dimensionality remain finite. Based on this result we derive methods, one already known and one new to our knowledge, to estimate the sample eigenvalues when the population eigenvalues are known. However, usually the sample eigenvalues are known and the population eigenvalues are required. We therefore applied one of the these methods in a feedback loop, resulting in an eigenvalue bias correction method. We compare this eigenvalue correction method with the state-of-the-art methods and show that our method outperforms other methods particularly in real-life situations often encountered in biometrics: underdetermined configurations, high-dimensional configurations, and configurations where the eigenvalues are exponentially distributed.

  14. Temperature-related risk factors associated with the colonization of broiler-chicken flocks with Campylobacter spp. in Iceland, 2001-2004

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our objective was to identify temperature-related risk factors associated with the colonization of broiler-chicken flocks with Campylobacter spp. in Iceland, with an underlying assumption that at minimum ambient temperatures, flies (Musca domestica) play a role in the epidemiology and seasonality of...

  15. High Q-factor sapphire whispering gallery mode microwave resonator at single photon energies and millikelvin temperatures

    NASA Astrophysics Data System (ADS)

    Creedon, Daniel L.; Reshitnyk, Yarema; Farr, Warrick; Martinis, John M.; Duty, Timothy L.; Tobar, Michael E.

    2011-05-01

    The microwave properties of a crystalline sapphire dielectric whispering gallery mode resonator have been measured at very low excitation strength (E /ℏω≈1) and low temperatures (T ≈30 mK). The measurements were sensitive enough to observe saturation due to a highly detuned electron spin resonance, which limited the loss tangent of the material to about 2×10-8 measured at 13.868 and 13.259 GHz. Small power dependent frequency shifts were also measured which correspond to an added magnetic susceptibility of order 10-9. This work shows that quantum limited microwave resonators with Q-factors >108 are possible with the implementation of a sapphire whispering gallery mode system.

  16. Stable isotope composition in Daphnia is modulated by growth, temperature, and toxic exposure: implications for trophic magnification factor assessment.

    PubMed

    Ek, Caroline; Karlson, Agnes M L; Hansson, Sture; Garbaras, Andrius; Gorokhova, Elena

    2015-06-01

    The potential for using stable isotope analysis in risk assessment of environmental contaminants is crucially dependent on the predictability of the trophic transfer of isotopes in food webs. The relationship between contaminant levels and trophic position of consumers is widely used to assess biomagnification properties of various pollutants by establishing trophic magnification factors (TMF). However, contaminant-induced variability of the isotopic composition in biota is poorly understood. Here, we investigated effects of toxic exposure on δ(15)N and δ(13)C values in a consumer, with a main hypothesis that these effects would be largely mediated via growth rate and metabolic turnover of the test animals. The cladoceran Daphnia magna was used in two experiments that were conducted to manipulate growth and body condition (assayed as C:N ratio) by food availability and temperature (Experiment 1) and by toxic exposure to the pesticide lindane (Experiment 2). We found a significant negative effect of growth rate and a positive effect of temperature on the consumer-diet discrimination factor for δ(15)N and δ(13)C, with no effects on the C:N ratio (Experiment 1). In lindane-exposed daphnids, a significant growth inhibition was observed, with concomitant increase in metabolic costs and significantly elevated size-specific δ(15)N and δ(13)C values. Moreover, a significantly higher incorporation of carbon relative to nitrogen, yet a concomitant decrease in C:N ratio was observed in the exposed animals. Together, these results have methodological implications for determining trophic positions and TMF in polluted environments, where elevated δ(15)N values would translate into overestimated trophic positions and underestimated TMF. Furthermore, altered δ(13)C values may lead to erroneous food-chain assignment of the consumer in question.

  17. Temperature-dependent rotational relaxation in a viscous alkane: Interplay of shape factor and boundary condition on molecular rotation

    NASA Astrophysics Data System (ADS)

    Dutt, G. B.; Sachdeva, A.

    2003-05-01

    Rotational relaxation of three organic solutes, coumarin 6 (C6), 2,5-dimethyl-1, 4-dioxo3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP), and nile red (NR), that are similar in size but distinct in shape has been studied in a nonpolar solvent, squalane as a function of temperature to find out how the mechanical friction experienced by the solute molecule is influenced by its shape. It has been observed that C6 rotates slowest followed by NR and DMDPP. The results are analyzed using Stokes-Einstein-Debye (SED) hydrodynamic theory and also quasihydrodynamic theories of Gierer and Wirtz, and Dote, Kivelson, and Schwartz. Analysis of the data using the SED theory reveals that the measured reorientation times of C6 and DMDPP follow subslip behavior whereas those of NR are found to match slip predictions. While no single model could mimic the observed trend even in a qualitative manner, the reorientation times of C6 and DMDPP when normalized by their respective shape factors and boundary-condition parameters can be scaled on a common curve over the entire range of temperature studied. The probable reasons for the distinctive rotational behavior of NR as compared to C6 and DMDPP are explained in terms of its molecular shape and how this in turn influences the boundary-condition parameter are discussed.

  18. Heat Shock Factor Genes of Tall Fescue and Perennial Ryegrass in Response to Temperature Stress by RNA-Seq Analysis

    PubMed Central

    Wang, Yan; Dai, Ya; Tao, Xiang; Wang, Jia-Zhen; Cheng, Hai-Yang; Yang, Hong; Ma, Xin-Rong

    2016-01-01

    Heat shock factors (Hsfs) are important regulators of stress-response in plants. However, our understanding of Hsf genes and their responses to temperature stresses in two Pooideae cool-season grasses, Festuca arundinacea, and Lolium perenne, is limited. Here we conducted comparative transcriptome analyses of plant leaves exposed to heat or cold stress for 10 h. Approximately, 30% and 25% of the genes expressed in the two species showed significant changes under heat and cold stress, respectively, including subsets of Hsfs and their target genes. We uncovered 74 Hsfs in F. arundinacea and 52 Hsfs in L. perenne, and categorized these genes into three subfamilies, HsfA, HsfB, and HsfC based on protein sequence homology to known Hsf members in model organisms. The Hsfs showed a strong response to heat and/or cold stress. The expression of HsfAs was elevated under heat stress, especially in class HsfA2, which exhibited the most dramatic responses. HsfBs were upregulated by the both temperature conditions, and HsfCs mainly showed an increase in expression under cold stress. The target genes of Hsfs, such as heat shock protein (HSP), ascorbate peroxidase (APX), inositol-3-phosphate synthase (IPS), and galactinol synthase (GOLS1), showed strong and unique responses to different stressors. We comprehensively detected Hsfs and their target genes in F. arundinacea and L. perenne, providing a foundation for future gene function studies and genetic engineering to improve stress tolerance in grasses and other crops. PMID:26793208

  19. Identification, classification, and expression profiles of heat shock transcription factors in tea plant (Camellia sinensis) under temperature stress.

    PubMed

    Liu, Zhi-Wei; Wu, Zhi-Jun; Li, Xing-Hui; Huang, Ying; Li, Hui; Wang, Yong-Xin; Zhuang, Jing

    2016-01-15

    In vascular plants, heat shock transcription factors (Hsfs) regulate heat stress response by regulating the expression of heat shock proteins. This study systematically and comprehensively analyzed the Hsf family in tea plant [Camellia sinensis (L.) O. Kuntze]. A total of 16 CsHsfs were identified from the transcriptome database of tea plant and analyzed for their phylogenetic relationships, motifs, and physicochemical characteristics. On the basis of the phylogenetic comparison of tea plant with Arabidopsis thaliana, Populus trichocarpa, Theobroma cacao, and Oryza sativa, the CsHsfs were classified into three classes, namely, A (56.25%), B (37.50%), and C (6.25%). Heat mapping showed that the expression profiles of CsHsf genes under non-stress conditions varied among four tea plant cultivars, namely, 'Yunnanshilixiang', 'Chawansanhao', 'Ruchengmaoyecha', and 'Anjibaicha'. Six CsHsf genes (CsHsfA1a, CsHsfA1b, CsHsfA6, CsHsfB1, CsHsfB2b, and CsHsfC1) were selected from classes A, B, and C to analyze the expression profiles of CsHsf genes through quantitative real-time PCR in 'Yingshuang', 'Anjibaicha', and 'Yunnanshilixiang' under high (38 °C) or low (4 °C) temperature stress. Temperature stress positively or negatively regulated all of the selected CsHsf genes, and the expression levels evidently varied even among CsHsf genes belonging to the same class. This study provided a relatively detailed summary of Hsfs in tea plant and may serve as a reference for further studies on the mechanism of temperature stress regulation by CsHsfs.

  20. Identification, classification, and expression profiles of heat shock transcription factors in tea plant (Camellia sinensis) under temperature stress.

    PubMed

    Liu, Zhi-Wei; Wu, Zhi-Jun; Li, Xing-Hui; Huang, Ying; Li, Hui; Wang, Yong-Xin; Zhuang, Jing

    2016-01-15

    In vascular plants, heat shock transcription factors (Hsfs) regulate heat stress response by regulating the expression of heat shock proteins. This study systematically and comprehensively analyzed the Hsf family in tea plant [Camellia sinensis (L.) O. Kuntze]. A total of 16 CsHsfs were identified from the transcriptome database of tea plant and analyzed for their phylogenetic relationships, motifs, and physicochemical characteristics. On the basis of the phylogenetic comparison of tea plant with Arabidopsis thaliana, Populus trichocarpa, Theobroma cacao, and Oryza sativa, the CsHsfs were classified into three classes, namely, A (56.25%), B (37.50%), and C (6.25%). Heat mapping showed that the expression profiles of CsHsf genes under non-stress conditions varied among four tea plant cultivars, namely, 'Yunnanshilixiang', 'Chawansanhao', 'Ruchengmaoyecha', and 'Anjibaicha'. Six CsHsf genes (CsHsfA1a, CsHsfA1b, CsHsfA6, CsHsfB1, CsHsfB2b, and CsHsfC1) were selected from classes A, B, and C to analyze the expression profiles of CsHsf genes through quantitative real-time PCR in 'Yingshuang', 'Anjibaicha', and 'Yunnanshilixiang' under high (38 °C) or low (4 °C) temperature stress. Temperature stress positively or negatively regulated all of the selected CsHsf genes, and the expression levels evidently varied even among CsHsf genes belonging to the same class. This study provided a relatively detailed summary of Hsfs in tea plant and may serve as a reference for further studies on the mechanism of temperature stress regulation by CsHsfs. PMID:26431998

  1. DARHT Radiographic Grid Scale Correction

    SciTech Connect

    Warthen, Barry J.

    2015-02-13

    Recently it became apparent that the radiographic grid which has been used to calibrate the dimensional scale of DARHT radiographs was not centered at the location where the objects have been centered. This offset produced an error of 0.188% in the dimensional scaling of the radiographic images processed using the assumption that the grid and objects had the same center. This paper will show the derivation of the scaling correction, explain how new radiographs are being processed to account for the difference in location, and provide the details of how to correct radiographic image processed with the erroneous scale factor.

  2. Quantitative reconstruction of temperature in northern Japan for the last 2000 years and the influential factors to determine climatic fluctuation

    NASA Astrophysics Data System (ADS)

    Kawahata, Hodaka; Hatta, Yoshiki; Ota, Yuki; Yoshida, Akihiro; Habu, Junko

    2016-04-01

    A coastal sedimentary core at St. 5 in Uchiura Bay in northern Japan provided an opportunity to quantitatively estimate terrestrial atmospheric temperatures (AT) using the alkenone proxy because of their strong correlation with summer sea surface temperatures (SSTs) (r2 >0.90). In other words, when we can estimate SST, we can reconstruct AT quantitatively at high time resolution (10-30 years for the last 2K). During the last two millennia, SSTs fluctuated by 4.9 °C before 20 century, reaching two maximum in 1820 AD (22.3°C) and 760 AD (22.0 °C) and two minima around 145 AD (17.4 °C) and 1080 AD (17.4 °C). The SST profile is generally consistent with those obtained from western and central Japan by us (3 sites) and from East Asia by Cook (2013) but shows some differences. Although the MWP (Medieval Warm Period) was not identified in this study because a cold climate prevailed in 990-1100 AD. Particularly low temperatures around 1000-1100 AD can be verified by historical documents from in and around the ancient capital city of Kyoto (Ishii, 2002). The reconstructed SOI (Southern Oscillation Index) data suggest that the equatorial Pacific was predominantly in an El Niño phase in 900-1200 AD. Under modern conditions, during an El Niño episode, the Pacific high is weakened, with reduced atmospheric pressure in the western North Pacific in the vicinity of Japan. This results in an enhanced Okhotsk high, which tends to be accompanied by a cold and cloudy/rainy summer in Japan. A cold climate was definitely observed in 1550-1700 AD, which almost corresponded to the LIA (Little Ice Age). A cold event around 1650 AD can be attributed to big eruptions at Komagatake. This resulted in severe cold type of famine, which is evidenced by historical documents. Because several factors, including external forcing (e.g., solar activity) and internal forcing (e.g., volcanic activity, ENSO, and the Asian monsoon), can affect the climate, we compared SST fluctuations with each of

  3. Metabolic fingerprinting of gilthead seabream (Sparus aurata) liver to track interactions between dietary factors and seasonal temperature variations.

    PubMed

    Silva, Tomé S; da Costa, Ana M R; Conceição, Luís E C; Dias, Jorge P; Rodrigues, Pedro M L; Richard, Nadège

    2014-01-01

    Farmed gilthead seabream is sometimes affected by a metabolic syndrome, known as the "winter disease", which has a significant economic impact in the Mediterranean region. It is caused, among other factors, by the thermal variations that occur during colder months and there are signs that an improved nutritional status can mitigate the effects of this thermal stress. For this reason, a trial was undertaken where we assessed the effect of two different diets on gilthead seabream physiology and nutritional state, through metabolic fingerprinting of hepatic tissue. For this trial, four groups of 25 adult gilthead seabream were reared for 8 months, being fed either with a control diet (CTRL, low-cost commercial formulation) or with a diet called "Winter Feed" (WF, high-cost improved formulation). Fish were sampled at two time-points (at the end of winter and at the end of spring), with liver tissue being taken for FT-IR spectroscopy. Results have shown that seasonal temperature variations constitute a metabolic challenge for gilthead seabream, with hepatic carbohydrate stores being consumed over the course of the inter-sampling period. Regarding the WF diet, results point towards a positive effect in terms of performance and improved nutritional status. This diet seems to have a mitigating effect on the deleterious impact of thermal shifts, confirming the hypothesis that nutritional factors can affect the capacity of gilthead seabream to cope with seasonal thermal variations and possibly contribute to prevent the onset of "winter disease".

  4. Metabolic fingerprinting of gilthead seabream (Sparus aurata) liver to track interactions between dietary factors and seasonal temperature variations

    PubMed Central

    da Costa, Ana M.R.; Conceição, Luís E.C.; Dias, Jorge P.; Rodrigues, Pedro M.L.; Richard, Nadège

    2014-01-01

    Farmed gilthead seabream is sometimes affected by a metabolic syndrome, known as the “winter disease”, which has a significant economic impact in the Mediterranean region. It is caused, among other factors, by the thermal variations that occur during colder months and there are signs that an improved nutritional status can mitigate the effects of this thermal stress. For this reason, a trial was undertaken where we assessed the effect of two different diets on gilthead seabream physiology and nutritional state, through metabolic fingerprinting of hepatic tissue. For this trial, four groups of 25 adult gilthead seabream were reared for 8 months, being fed either with a control diet (CTRL, low-cost commercial formulation) or with a diet called “Winter Feed” (WF, high-cost improved formulation). Fish were sampled at two time-points (at the end of winter and at the end of spring), with liver tissue being taken for FT-IR spectroscopy. Results have shown that seasonal temperature variations constitute a metabolic challenge for gilthead seabream, with hepatic carbohydrate stores being consumed over the course of the inter-sampling period. Regarding the WF diet, results point towards a positive effect in terms of performance and improved nutritional status. This diet seems to have a mitigating effect on the deleterious impact of thermal shifts, confirming the hypothesis that nutritional factors can affect the capacity of gilthead seabream to cope with seasonal thermal variations and possibly contribute to prevent the onset of “winter disease”. PMID:25210655

  5. Eyeglasses for Vision Correction

    MedlinePlus

    ... Stories Español Eye Health / Glasses & Contacts Eyeglasses for Vision Correction Dec. 12, 2015 Wearing eyeglasses is an easy way to correct refractive errors. Improving your vision with eyeglasses offers the opportunity to select from ...

  6. Illinois Corrections Project Report

    ERIC Educational Resources Information Center

    Hungerford, Jack

    1974-01-01

    The Illinois Corrections Project for Law-Focused Education, which brings law-focused curriculum into corrections institutions, was initiated in 1973 with a summer institute and includes programs in nine particpating institutions. (JH)

  7. B_c B_c J/ψ vertex form factor at finite temperature in the framework of QCD sum rules approach

    NASA Astrophysics Data System (ADS)

    Yazici, E.; Sundu, H.; Veliev, E. Veli

    2016-02-01

    The strong form factor of the Bc BcJ/Ψ vertex is calculated in the framework of the QCD sum rules method at finite temperature. Taking into account additional operators appearing at finite temperature, a thermal Wilson expansion is obtained and QCD sum rules are derived. While increasing the temperature, the strong form factor remains unchanged up to T˜eq 100 MeV but slightly increases after this point. After T˜eq 160 MeV, the form factor suddenly decreases up to T˜eq 170 MeV. The obtained result of the coupling constant by fitting the form factor at Q^2=-m^2_{offshell} at T=0 is in a very good agreement with the QCD sum rules calculations in the case of vacuum. Our prediction can be checked in future experiments.

  8. Regulation of biosynthesis and emission of volatile phenylpropanoids/benzenoids in petunia× hybrida flowers by multi-factors of circadian clock, light, and temperature.

    PubMed

    Cheng, Sihua; Fu, Xiumin; Mei, Xin; Zhou, Ying; Du, Bing; Watanabe, Naoharu; Yang, Ziyin

    2016-10-01

    Floral volatile phenylpropanoids and benzenoids (VPBs) play important ecological functions and have potential economic applications. Little is known about how multi-factors in integration regulate the formation and emission of floral VPBs. In the present study, we investigated effects of multi factors including endogenous circadian clock, light, and temperature on the formation and emission of VPBs, which are major volatiles in flowers of Petunia× hybrida cv. 'Mitchell Diploid'. Endogenous circadian clock was proposed as the most important factor regulating rhythmic emission of VPBs and expressions of structural genes involved in the upstream biosynthetic pathway of VPBs, but did not affect expression levels of structural genes involved in the downstream pathway and VPBs-related regulators. In contrast to light, temperature was a more constant factor affecting emission of VPBs. VPBs emission could be inhibited within a short time by increasing temperature. The information will contribute to our understanding of emission mechanism of floral volatiles. PMID:27235646

  9. Phylogenetic position of symbiotic protist Dinenympha [correction of Dinemympha] exilis in the hindgut of the termite Reticulitermes speratus inferred from the protein phylogeny of elongation factor 1 alpha.

    PubMed

    Moriya, S; Ohkuma, M; Kudo, T

    1998-04-14

    The phylogenetic position of the symbiotic oxymonad Dinenympha exilis, found in the hindgut of the lower termite Reticulitermes speratus, was determined by analysis of translation elongation factor 1 alpha (EF-1 alpha). cDNA corresponding to a major part of the amino acid coding region of EF-1 alpha mRNA was amplified by the reverse transcription polymerase chain reaction (RT-PCR) method from total mRNA of termite hindgut microorganisms without cultivation. The product was cloned into a plasmid vector, pGEM-T, and the clones were isolated and sequenced. One of the EF-1 alpha clones isolated was assigned to the protist D. exilis by whole-cell in-situ hybridization using a specific oligonucleotide probe with enzymatic signal amplification. The deduced amino acid sequence was aligned with those of other eukaryotic and archaeabacterial EF-1 alpha s, and the phylogenetic relationships among early branching eukaryotes were inferred by using the distance matrix method and the maximum parsimony method. The phylogenetic analysis indicated that the D. exilis offshoot occurred before mitochondria-containing organisms and D. exilis branched out after the diplomonads clade. These results indicate that the oxymonad D. exilis is one of the early branching organisms and suggest that the oxymonads form a lineage independent of other early branching organisms. PMID:9573371

  10. Effects of lipid and urea extraction on δ15N values of deep-sea sharks and hagfish: Can mathematical correction factors be generated?

    NASA Astrophysics Data System (ADS)

    Churchill, Diana A.; Heithaus, Michael R.; Dean Grubbs, R.

    2015-05-01

    Stable isotope analysis is broadly employed to investigate diverse ecological questions. In order to make appropriate comparisons among multiple taxa, however, it is necessary to standardize values to account for interspecific differences in factors that affect isotopic ratios. For example, varying concentrations of soluble nitrogen compounds, such as urea or trimethylamine oxide, can affect the analysis and interpretation of δ15N values of sharks or hagfish. The goal of this study was to assess the effects of a standard chloroform/methanol extraction on the stable isotope values of muscle tissue obtained from 10 species of sharks and three species of hagfish collected from poorly-known deep-water (>200 m) communities. We detected significant differences in δ15N, %N, and C:N values as a result of extractions in 8 of 10 shark and all three hagfish species. We observed increased δ15N values, but shifts in %N and C:N values were not unidirectional. Mathematical normalizations for δ15N values were successfully created for four shark and two hagfish species. However, they were not successful for two shark species. Therefore, performing extractions of all samples is recommended.

  11. Pion scalar form factor with correct mass and width of scalar mesons f0(500 ) and f0(980 )

    NASA Astrophysics Data System (ADS)

    Dubnicka, Stanislav; Dubnickova, Anna Zuzana; Kamiński, Robert; Liptaj, Andrej

    2016-09-01

    Construction of the pion scalar isoscalar form factor Γπ(t ) in the elastic region, with an emphasis on the values of the S-wave isoscalar π π scattering length a00 and the quadratic pion scalar radius ⟨r2⟩sπ to be in conformity with predictions of the chiral perturbation theory, is presented. It is based on a precise S-wave isoscalar π π scattering phase shift generated by dispersive analysis of experimental data with and imposed crossing symmetry condition. The final result for values of the f0(500 ) scalar meson mass and width is mσ=(487 ±31 ) MeV ; Γσ=(542 ±60 ) MeV and for values of the f0(980 ) scalar meson mass and width is mf (980 )=(988 ±78 ) MeV ; Γf (980 )=(97 ±29 ) MeV . The f0(500 ) scalar meson parameters are compatible with the results from dispersive analyses of the BERN and MADRID/CRACOW groups to be considered now as the most reliable values of the f0(500 ) scalar meson parameters, though in presented analysis another, unusual way has been applied. The f0(980 ) meson parameters agree well with values given by the Particle Data Group.

  12. Teaching Politically Correct Language

    ERIC Educational Resources Information Center

    Tsehelska, Maryna

    2006-01-01

    This article argues that teaching politically correct language to English learners provides them with important information and opportunities to be exposed to cultural issues. The author offers a brief review of how political correctness became an issue and how being politically correct influences the use of language. The article then presents…

  13. Research in Correctional Rehabilitation.

    ERIC Educational Resources Information Center

    Rehabilitation Services Administration (DHEW), Washington, DC.

    Forty-three leaders in corrections and rehabilitation participated in the seminar planned to provide an indication of the status of research in correctional rehabilitation. Papers include: (1) "Program Trends in Correctional Rehabilitation" by John P. Conrad, (2) "Federal Offenders Rahabilitation Program" by Percy B. Bell and Merlyn Mathews, (3)…

  14. Mitochondria are the target organelle of differentiation-inducing factor-3, an anti-tumor agent isolated from Dictyostelium discoideum [corrected].

    PubMed

    Kubohara, Yuzuru; Kikuchi, Haruhisa; Matsuo, Yusuke; Oshima, Yoshiteru; Homma, Yoshimi

    2013-01-01

    Differentiation-inducing factor-3 (DIF-3), found in the cellular slime mold Dictyostelium discoideum, and its derivatives such as butoxy-DIF-3 (Bu-DIF-3) are potent anti-tumor agents. However, the precise mechanisms underlying the actions of DIF-3 remain to be elucidated. In this study, we synthesized a green fluorescent derivative of DIF-3, BODIPY-DIF-3, and a control fluorescent compound, Bu-BODIPY (butyl-BODIPY), and investigated how DIF-like molecules behave in human cervical cancer HeLa cells by using both fluorescence and electron microscopy. BODIPY-DIF-3 at 5-20 µ M suppressed cell growth in a dose-dependent manner, whereas Bu-BODIPY had minimal effect on cell growth. When cells were incubated with BODIPY-DIF-3 at 20 µM, it penetrated cell membranes within 0.5 h and localized mainly in mitochondria, while Bu-BODIPY did not stain the cells. Exposure of cells for 1-3 days to DIF-3, Bu-DIF-3, BODIPY-DIF-3, or CCCP (a mitochondrial uncoupler) induced substantial mitochondrial swelling, suppressing cell growth. When added to isolated mitochondria, DIF-3, Bu-DIF-3, and BOIDPY-DIF-3, like CCCP, dose-dependently promoted the rate of oxygen consumption, but Bu-BODIPY did not. Our results suggest that these bioactive DIF-like molecules suppress cell growth, at least in part, by disturbing mitochondrial activity. This is the first report showing the cellular localization and behavior of DIF-like molecules in mammalian tumor cells. PMID:23977224

  15. EDITORIAL: Politically correct physics?

    NASA Astrophysics Data System (ADS)

    Pople Deputy Editor, Stephen

    1997-03-01

    If you were a caring, thinking, liberally minded person in the 1960s, you marched against the bomb, against the Vietnam war, and for civil rights. By the 1980s, your voice was raised about the destruction of the rainforests and the threat to our whole planetary environment. At the same time, you opposed discrimination against any group because of race, sex or sexual orientation. You reasoned that people who spoke or acted in a discriminatory manner should be discriminated against. In other words, you became politically correct. Despite its oft-quoted excesses, the political correctness movement sprang from well-founded concerns about injustices in our society. So, on balance, I am all for it. Or, at least, I was until it started to invade science. Biologists were the first to feel the impact. No longer could they refer to 'higher' and 'lower' orders, or 'primitive' forms of life. To the list of undesirable 'isms' - sexism, racism, ageism - had been added a new one: speciesism. Chemists remained immune to the PC invasion, but what else could you expect from a group of people so steeped in tradition that their principal unit, the mole, requires the use of the thoroughly unreconstructed gram? Now it is the turn of the physicists. This time, the offenders are not those who talk disparagingly about other people or animals, but those who refer to 'forms of energy' and 'heat'. Political correctness has evolved into physical correctness. I was always rather fond of the various forms of energy: potential, kinetic, chemical, electrical, sound and so on. My students might merge heat and internal energy into a single, fuzzy concept loosely associated with moving molecules. They might be a little confused at a whole new crop of energies - hydroelectric, solar, wind, geothermal and tidal - but they could tell me what devices turned chemical energy into electrical energy, even if they couldn't quite appreciate that turning tidal energy into geothermal energy wasn't part of the

  16. Magnesium correction to the NaKCa chemical geothermometer

    USGS Publications Warehouse

    Fournier, R.O.; Potter, R.W., II

    1979-01-01

    Equations and graphs have been devised to correct for the adverse effects of magnesium upon the Na-K-Ca chemical geothermometer. Either the equations or graphs can be used to determine appropriate temperature corrections for given waters with calculated NaKCa temperatures > 70??C and R 50 are probably derived from relatively cool aquifers with temperatures approximately equal to the measured spring temperature, irrespective of much higher calculated Na-K-Ca temperatures. ?? 1979.

  17. Soil microbial respiration rate and temperature sensitivity along a north-south forest transect in eastern China: Patterns and influencing factors

    NASA Astrophysics Data System (ADS)

    Wang, Qing; He, Nianpeng; Yu, Guirui; Gao, Yang; Wen, Xuefa; Wang, Rongfu; Koerner, Sally E.; Yu, Qiang

    2016-02-01

    Soil organic matter is one of the most important carbon (C) pools in terrestrial ecosystems, and future warming from climate change will likely alter soil C storage via temperature effects on microbial respiration. In this study, we collected forest soils from eight locations along a 3700 km north-south transect in eastern China (NSTEC). For 8 weeks these soils were incubated under a periodically changing temperature range of 6-30°C while frequently measuring soil microbial respiration rate (Rs; each sample about every 20 min). This experimental design allowed us to investigate Rs and the temperature sensitivity of Rs (Q10) along the NSTEC. Both Rs at 20°C (R20) and Q10 significantly increased (logarithmically) with increasing latitude along the NSTEC suggesting that the sensitivity of soil microbial respiration to changing temperatures is higher in forest soils from locations with lower temperature. Our findings from an incubation experiment provide support for the hypothesis that temperature sensitivity of soil microbial respiration increases with biochemical recalcitrance (C quality-temperature hypothesis) across forest soils on a large spatial scale. Furthermore, microbial properties primarily controlled the observed patterns of R20, whereas both substrate and microbial properties collectively controlled the observed patterns of Q10. These findings advance our understanding of the driving factors (microbial versus substrate properties) of R20 and Q10 as well as the general relationships between temperature sensitivity of soil microbial respiration and environmental factors.

  18. Influence of manufacturing