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1

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

SciTech Connect

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.

Arevalo, J.; McCarthy, K. J.; Carmona, J. M.; Fontdecaba, J. M. [Laboratorio Nacional de Fusion, Association Euratom-Ciemat, E-28040 Madrid (Spain)

2010-10-15

2

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

PubMed

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??m diameter fibers collect and transmit light to curved 100??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. PMID:21033898

Arévalo, J; McCarthy, K J; Carmona, J M; Fontdecaba, J M

2010-10-01

3

Temperature Corrected Bootstrap Algorithm  

NASA Technical Reports Server (NTRS)

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.

Comiso, Joey C.; Zwally, H. Jay

1997-01-01

4

Theoretical full power correction factors as related to changes in ambient temperature, pressure and absolute humidity for aircraft turbine engines  

E-print Network

and of the ambient atmospheric temperature. 61 SYMBOLS, SUBSCRIPTS AND UNITS ~Smb o 1, Definition Temperature p = Pres sure PR = Pressure Ratio h . = Enthalpy m = Mass flow rate s = Entropy v = Specific volume Units. Kelvin ('K) ' Rankine ('R) Fahrenheit... and of the ambient atmospheric temperature. 61 SYMBOLS, SUBSCRIPTS AND UNITS ~Smb o 1, Definition Temperature p = Pres sure PR = Pressure Ratio h . = Enthalpy m = Mass flow rate s = Entropy v = Specific volume Units. Kelvin ('K) ' Rankine ('R) Fahrenheit...

Raphael, Michel Antoun

2012-06-07

5

Use supercompressibility as a meter correction factor  

SciTech Connect

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/.

Nelson, M.B.

1982-09-01

6

49 CFR 325.73 - Microphone distance correction factors. 1  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Microphone distance correction factors. 1 325.73 Section...Correction Factors § 325.73 Microphone distance correction factors. 1 1 Table...readings taking into account both the distance correction factors contained in §...

2010-10-01

7

ZETA converter applied in power factor correction  

Microsoft Academic Search

This paper presents the analysis of the ZETA converter operating in discontinuous conduction mode (DCM) for power factor correction. The main attraction of the ZETA converter is that it is a naturally isolated structure, which allows a regulated output voltage with only one power processing stage. The principle of operation, mathematical analysis, design procedure and experimental results obtained from a

ADRIANO PERES; DENIZAR CRUZ MARTINS; I. Barbi

1994-01-01

8

Corrections to temperature measurements with a sonic anemometer  

Microsoft Academic Search

Methods of correcting the temperature output of a sonic anemometer-thermometer are examined. The errors in the temperature variance and flux are evaluated as a function of stability and examples given of correcting the sonic-derived temperature point by point. It is concluded that, in general, both humidity and crosswind corrections must be included.

P. Hignett

1992-01-01

9

Scale-factor corrections in large ring lasers  

NASA Astrophysics Data System (ADS)

The authors report on fluctuations of the geometric scale factor of a very large ring laser situated 30m underground in the Cashmere Cavern in Christchurch (New Zealand). Variations in temperature and atmospheric pressure cause thermoelastic deformations to the cavern, which lead to changes of the area and perimeter of the ring laser structure. In situ beam monitoring has been used to partially correct for these effects.

Pritsch, B.; Schreiber, K. U.; Velikoseltsev, A.; Wells, J.-P. R.

2007-08-01

10

Development of a Pressure Sensitive Paint System with Correction for Temperature Variation  

NASA Technical Reports Server (NTRS)

Pressure Sensitive Paint (PSP) is known to provide a global image of pressure over a model surface. However, improvements in its accuracy and reliability are needed. Several factors contribute to the inaccuracy of PSP. One major factor is that luminescence is temperature dependent. To correct the luminescence of the pressure sensing component for changes in temperature, a temperature sensitive luminophore incorporated in the paint allows the user to measure both pressure and temperature simultaneously on the surface of a model. Magnesium Octaethylporphine (MgOEP) was used as a temperature sensing luminophore, with the pressure sensing luminophore, Platinum Octaethylporphine (PtOEP), to correct for temperature variations in model surface pressure measurements.

Simmons, Kantis A.

1995-01-01

11

An Analysis of Ionization Correction Factors in Planetary Nebulae  

NASA Astrophysics Data System (ADS)

I will present here some of the results derived from our recent analysis of ionization correction factors (ICFs) in planetary nebulae (PNe). We compute an extensive grid of ~15000 photoionization models using the c10.00 version of Cloudy code (Ferland et al. 1998) that cover a wide range of effective temperatures, nebular radius, luminosities, and gas densities. We use both blackbodies and Rauch atmospheres as ionizing sources, and we calculate constant and non-constant density models as well as radiation-and matter-bounded models. We derive new ICFs for PNe and their associated uncertainties. I will discuss the differences with previous ICFs used in the literature.

Delgado-Inglada, G.

2014-04-01

12

Harmonic measurements and analysis for power factor correction  

SciTech Connect

Nonlinear characteristics of furnace arcs during melting and rolling mill drives generate harmonic currents that can cause system voltage distortion, power loss and an interaction with power factor correction capacitor banks leading to equipment failures. An analytical technique used to correct power factor includes field measurement, system analysis and filter design to reduce harmonic distortion.

Andrews, D. (North Star Steel, Beaumont, TX (United States)); Bishop, M.T.; Witte, J.F. (Cooper Power Systems, Franksville, WI (United States))

1994-04-01

13

Temperature-Corrected Model of Turbulence in Hot Jet Flows  

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

14

Geometrical correction factors for heat flux meters  

NASA Technical Reports Server (NTRS)

General formulas are derived for determining gage averaging errors of strip-type heat flux meters used in the measurement of one-dimensional heat flux distributions. The local averaging error e(x) is defined as the difference between the measured value of the heat flux and the local value which occurs at the center of the gage. In terms of e(x), a correction procedure is presented which allows a better estimate for the true value of the local heat flux. For many practical problems, it is possible to use relatively large gages to obtain acceptable heat flux measurements.

Baumeister, K. J.; Papell, S. S.

1974-01-01

15

Second Order Corrections to QED Coupling at Low Temperature  

E-print Network

We calculate the second order corrections to vacuum polarization tensor of photons at low temperatures, i.e; T $\\le 10^{10}$ K ($T QED coupling constant are evaluated at temperatures below the electron mass that is $TQED at these temperatures has explicitly been checked. The electromagnetic properties of such a thermal medium are modified. Parameters like electric permittivity and magnetic permeability of such a medium are no more constant and become functions of temperature.

Masood, S S; Haseeb, Mahnaz Q.; Masood, Samina S.

2006-01-01

16

Second Order Corrections to QED Coupling at Low Temperature  

E-print Network

We calculate the second order corrections to vacuum polarization tensor of photons at low temperatures, i.e; T $\\le 10^{10}$ K ($T QED coupling constant are evaluated at temperatures below the electron mass that is $TQED at these temperatures has explicitly been checked. The electromagnetic properties of such a thermal medium are modified. Parameters like electric permittivity and magnetic permeability of such a medium are no more constant and become functions of temperature.

Samina S. Masood; Mahnaz Q. Haseeb

2006-12-11

17

SURVIVING “THE JOINT”: MITIGATING FACTORS OF CORRECTIONAL OFFICER STRESS  

Microsoft Academic Search

Many studies have focused upon the effect of stress upon police and correctional officers. This study investigates the relationship between stressors, coping mechanisms, and three types of stress (job dissatisfaction, work stress, and life stress) encountered by correctional officers. Factors such as danger, education, and supervisory support, experience and court decisions are considered in the multivariate model.

Elizabeth L. Grossi; Thomas J. Keil; Gennaro F. Vito

1996-01-01

18

Application of bottom-hole temperature corrections in geothermal studies  

SciTech Connect

Bottom-hole temperature (BHT) data measured in oil and gas wells constitute a large, low-quality set of temperature observations commonly used in geothermal studies. Raw BHT data are, on the average, cooler than true formation temperatures. To estimate true formation temperatures, corrections must be applied. Empirical BHT corrections may be applied to BHT data for which only depths of measurement are known, but may not be valid outside of the area for which they are calibrated. If multiple BHT measurements from successive logging runs are available, the Horner plot correction procedure can be used. The accuracy of the Horner plot is limited by simplifying assumptions made in its derivation, and by the common lack of information on parameters such as duration of mud circulation. More detailed and complete treatments provide insight into the borehole equilibration process, but their application is similarly limited by a common lack of data regarding borehole thermal properties. A new type of empirical correction procedure may be derived in some areas and allows a correction to be made for BHTs for which only a depth and time of measurement are known.

Deming, D. (Dept. of Geology and Geophysics, Louisiana State Univ., Baton Rouge, LA (US))

1989-01-01

19

Measuring accurate IOPs: Does correction factor help or hurt?  

PubMed Central

Purpose: To evaluate if using the Ehlers correction factor on the intraocular pressure (IOP) measured using the Goldmann applanation tonometer (GAT) improves its agreement with the PASCAL dynamic contour tonometer (DCT). Patients and methods: A total of 120 eyes of 120 individuals were examined. Participants underwent IOP measurement with both the DCT and the GAT and central corneal thickness measurement. The Ehlers correction factor was applied on the GAT IOP measurements to calculate Ehlers-corrected GAT IOP. The agreement between the DCT and GAT, and DCT and Ehlers-corrected GAT IOP was analyzed. The analyses were repeated by stratifying the data by race. Results: The mean IOP of the GAT, DCT, and the Ehlers-corrected GAT was 15.30, 16.78, and 14.68 mmHg, respectively. The agreement as assessed by Bland–Altman plot for the GAT with the DCT and DCT and Ehlers-corrected GAT IOP was +4.1 to ?6.9 and +4.15 to ?8.25 mmHg, respectively. The results were similar even when stratifying the data by race. Conclusion: Using Ehlers correction factor to account for the effect of corneal parameters on the IOP measured by the GAT worsens the agreement with the DCT. This effect remains even when stratifying the data by race. PMID:20668723

Gunvant, Pinakin; Newcomb, Robert D; Kirstein, Elliot M; Malinovsky, Victor E; Madonna, Richard J; Meetz, Richard E

2010-01-01

20

Second-Order Corrections to QED Coupling at Low Temperature  

NASA Astrophysics Data System (ADS)

We calculate the second-order corrections to vacuum polarization tensor of photons at low temperatures, i.e. T ? 1010 K (T ? me). The thermal contributions to the QED coupling constant are evaluated at temperatures below the electron mass that is T < me. Renormalization of QED at these temperatures has explicitly been checked. The electromagnetic properties of such a thermal medium are modified. Parameters like electric permittivity and magnetic permeability of such a medium are no more constant and become functions of temperature.

Masood, Samina S.; Haseeb, Mahnaz

21

Radiative Equilibrium and Temperature Correction in Monte Carlo Radiation Transfer  

E-print Network

We describe a general radiative equilibrium and temperature correction procedure for use in Monte Carlo radiation transfer codes with sources of temperature-independent opacity, such as astrophysical dust. The technique utilizes the fact that Monte Carlo simulations track individual photon packets, so we may easily determine where their energy is absorbed. When a packet is absorbed, it heats a particular cell within the envelope, raising its temperature. To enforce radiative equilibrium, the absorbed packet is immediately re-emitted. To correct the cell temperature, the frequency of the re-emitted packet is chosen so that it corrects the temperature of the spectrum previously emitted by the cell. The re-emitted packet then continues being scattered, absorbed, and re-emitted until it finally escapes from the envelope. As the simulation runs, the envelope heats up, and the emergent spectral energy distribution (SED) relaxes to its equilibrium value, without iteration. This implies that the equilibrium temperature calculation requires no more computation time than the SED calculation of an equivalent pure scattering model with fixed temperature. In addition to avoiding iteration, our method conserves energy exactly, because all injected photon packets eventually escape. Furthermore, individual packets transport energy across the entire system because they are never destroyed. This long-range communication, coupled with the lack of iteration, implies that our method does not suffer the convergence problems commonly associated with lambda-iteration. To verify our temperature correction procedure, we compare our results to standard benchmark tests, and finally we present the results of simulations for two-dimensional axisymmetric density structures.

J. E. Bjorkman; Kenneth Wood

2001-03-15

22

A proposal for “correction values” for winter outdoor design temperatures  

Microsoft Academic Search

This study aims to find a correlation between winter outdoor design temperature (WDT) and mass of the building envelope. The daily variations of the inside surface temperatures and heat fluxes of the walls under various climatic conditions and different wall constructions have been calculated by a computer program based on the response factor technique, which uses variable outside air temperature

F Nur Demirbilek; Ceng Yener

1996-01-01

23

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

NASA Technical Reports Server (NTRS)

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.

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

1939-01-01

24

Ionization Correction Factors for Planetary Nebulae: I- Using optical spectra  

E-print Network

We compute a large grid of photoionization models that covers a wide range of physical parameters and is representative of most of the observed PNe. Using this grid, we derive new formulae for the ionization correction factors (ICFs) of He, O, N, Ne, S, Ar, Cl, and C. Analytical expressions to estimate the uncertainties arising from our ICFs are also provided. This should be useful since these uncertainties are usually not considered when estimating the error bars in element abundances. Our ICFs are valid over a variety of assumptions such as the input metallicities, the spectral energy distribution of the ionizing source, the gas distribution, or the presence of dust grains. Besides, the ICFs are adequate both for large aperture observations and for pencil-beam observations in the central zones of the nebulae. We test our ICFs on a large sample of observed PNe that extends as far as possible in ionization, central star temperature, and metallicity, by checking that the Ne/O, S/O, Ar/O, and Cl/O ratios show n...

Delgado-Inglada, Gloria; Stasi?ska, Gra?yna

2014-01-01

25

Ionization correction factors for planetary nebulae - I. Using optical spectra  

NASA Astrophysics Data System (ADS)

We compute a large grid of photoionization models that covers a wide range of physical parameters and is representative of most of the observed planetary nebulae (PNe). Using this grid, we derive new formulae for the ionization correction factors (ICFs) of He, O, N, Ne, S, Ar, Cl, and C. Analytical expressions to estimate the uncertainties arising from our ICFs are also provided. This should be useful since these uncertainties are usually not considered when estimating the error bars in element abundances. Our ICFs are valid over a variety of assumptions such as the input metallicities, the spectral energy distribution of the ionizing source, the gas distribution, or the presence of dust grains. Besides, the ICFs are adequate both for large aperture observations and for pencil-beam observations in the central zones of the nebulae. We test our ICFs on a large sample of observed PNe that extends as far as possible in ionization, central star temperature, and metallicity, by checking that the Ne/O, S/O, Ar/O, and Cl/O ratios show no trend with the degree of ionization. Our ICFs lead to significant differences in the derived abundance ratios as compared with previous determinations, especially for N/O, Ne/O, and Ar/O.

Delgado-Inglada, Gloria; Morisset, Christophe; Stasi?ska, Gra?yna

2014-05-01

26

Solar Correction Factors of Building Envelope in Tebei  

E-print Network

Tebei has very rich solar energy in China and needs heating in winter,but the present energy building design code has no solar correction factor for the overall heat transfer coefficient of building envelope for Tebei. Based on the typical year...

Wang, D.; Tang, M.

2006-01-01

27

Improved induction-heating inverter with power factor correction  

Microsoft Academic Search

An inverter aimed at induction heating applications is presented. It features power factor correction and fast response to sudden changes in the load, while providing the capability to vary the power supplied to the load. Power variation is achieved by means of pulse density modulation using variable-length sequences; thus allowing a high number of power levels to be achieved. The

Hugo Calleja; R. Ordonez

1999-01-01

28

Quantum Mechanical Corrections to Simulated Shock Hugoniot Temperatures  

SciTech Connect

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.

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

2009-07-17

29

Deriving time discounting correction factors for TTO tariffs.  

PubMed

The Time Trade-off (TTO) method is a popular method for valuing health state utilities and is frequently used in economic evaluations. However, this method produces utilities that are distorted by several biases. One important bias entails the failure to incorporate time discounting. This paper aims to measure time discounting for health outcomes in a sample representative for the general population. In particular, we estimate TTO scores alongside time discounting in order to derive a set of correction factors that can be employed to correct raw TTO scores for the downward bias caused by time discounting. We find substantial positive correction factors, which are increasing with the severity of the health state. Furthermore, higher discounting is found when using more severe health states in the discounting elicitation task. More research is needed to further develop discount rate elicitation procedures and test their validity, especially in general public samples. Moreover, future research should investigate the correction of TTO values for other biases as well, such as loss aversion, and to develop a criterion to test the external validity of TTO scores. PMID:23564665

Attema, Arthur E; Brouwer, Werner B F

2014-04-01

30

Nonlinear dynamics of power-factor-correction converter  

Microsoft Academic Search

The boost power-factor-correction (PFC) converter with average-current-mode control is a nonlinear system due to the effects of the multiplier and a large variation of the duty ratio. Although its stability analysis must be studied depending on a nonlinear model, most prior research attempted to make some assumptions to force this nonlinear system to be linear. As a result, the practical

Mohamed Orabi; Tamotsu Ninomiya

2003-01-01

31

Corrections for Convective Heat Flux Gauges Subjected to a Surface Temperature Discontinuity  

NASA Technical Reports Server (NTRS)

A two-dimensional Navier-Stokes computational fluid dynamics (CFD) analysis has been carried out in an effort to determine the convective heat transfer corrections for circular heat flux gauges subjected to a surface temperature discontinuity. Solutions were obtained at a Reynolds number Of 1 x 10(exp 6) and a Mach number of 4. The CFD results are compared with the existing correlations for the correction factors. In general, the CFD corrections exceed those provided by the correlations. The discrepancy increases with increasing upstream surface temperature, thus indicating the role of property variations, which are not accounted for in the correlations. A quasi-two-dimensional analysis is also performed to treat the cylindrical geometry of the heat flux gauges by area-averaging the computed two-dimensional results from CFD.

Kandula, M.; Reinarts, T.; Voska, N. (Technical Monitor)

2002-01-01

32

High-speed correction factor to the O(+)-O resonance charge exchange collision frequency  

NASA Technical Reports Server (NTRS)

The high-speed correction factor to the O(+)-O collision frequency, resulting from drift velocities between ions and neutrals, is calculated by solving the integral expression in this factor both numerically and analytically. Although the analytic solution is valid for either small or large drift velocities between ions and neutrals, for temperatures of interest and all drift velocities considered, agreement is found between analytic and detailed numerical integration results within less than 1% error. Let T(sub r) designate the average of the ion and neutral temperatures in K, and u = nu(sub d)/alpha, where nu(sub d) is the relative drift velocity in cm/s, and alpha = 4.56 x 10(exp 3) square root of T(sub r) cm/s is the thermal velocity of the O(+)-O system. Then, as u ranges from 0 to 2, the correction factor multiplying the collision frequency increases monotonically from 1 to about 1.5. An interesting result emerging from this calculation is that the correction factor for temperatures of aeronomical interest is to a good approximation independent of the temperature, depending only on the scaled velocity u.

Omidvar, K.; Pesnell, W. D.

1995-01-01

33

Harmonic measurements and analysis for power factor correction  

SciTech Connect

Maximizing electric power transfer directly effects the productivity of an electric arc furnace operation. Arc furnaces and rolling mill loads operate at power factors that result in penalty charges and lower bus voltages. In addition, the nonlinear characteristics of the furnace arcs and rolling mill drives generate significant harmonic currents that flow through the plant and utility power system. These harmonic currents cause system voltage distortions, power loss in the system, and can interact with power factor correction capacitor banks leading to equipment failures. This paper presents the analytical technique used to correct power factor in a modern steel manufacturing facility. The study included field measurements, harmonic analysis, and filter design work to reduce the amount of harmonic distortion in the plant. The modeling of arc furnaces and rolling mills for a harmonic analysis study is also discussed. The solution recommended in this paper to increase power factor and reduce harmonics can be applied to other steel manufacturing facilities to improve power quality and therefore plant productivity.

Witte, J.F.; Bishop, M.T. (Cooper Power Systems, Franksville, WI (United States)); Andrews, D. (North Star Steel Texas, Inc., Beaumont, TX (United States))

1993-07-01

34

Temperature corrections in the Priestley-Taylor equation of evaporation  

NASA Astrophysics Data System (ADS)

The Priestley-Taylor equation (PTE) is frequently applied in actual areal evapotranspiration (ET) estimation methods for obtaining the maximum daily rate of evaporation with data from sub-humid conditions. Since PTE was parameterized under humid conditions, a temperature correction is necessary to avoid overestimation of the maximum rate of ET. Wet-environment surface temperature (Tws), a proxy of the wet-environment air temperature (Twa), is estimated by the Szilagyi-Jozsa (SJ) approach as well as by a re-parameterized version of Monteith. The latter yields higher values but typically within 1 °C of the former. Tested by daily FLUXNET data, the estimates are only mildly sensitive to the mean daily wind velocity which thus can be replaced by a region-representative monthly average. From long-term simplified water-balances - plus monthly Moderate Resolution Imaging Spectroradiometer (MODIS) and ERA-Interim re-analysis data - the re-parameterized Monteith method appears to yield more accurate Tws estimates, while the PTE performs better with the SJ provided Tws values since they are closer to Twa, the PTE expects. Both methods require net radiation, air temperature, humidity and monthly mean wind velocity values plus ground heat fluxes when employed on a daily basis.

Szilagyi, Jozsef

2014-11-01

35

Power Factor Correction in Cycle Control with Divided Output Capacitors  

NASA Astrophysics Data System (ADS)

A power factor correction scheme using a cycle-control is proposed without switching devices, where output voltage can be much reduced. A certain application requires such control like significantly lowering the output voltage. In the proposed method, the output capacitor is divided into two parts, in which the input current waveform becomes balanced one. Hence, the harmonic characteristics can be much improved, where the lower order harmonics, such as the fifth and seventh orders are sufficiently reduced. The results are confirmed by the theoretical and experimental implementations.

Yamamoto, Isamu; Matsui, Keiju; Mori, Hideki; Kojima, Hiroo; Ando, Kenji; Fujimatsu, Ichiro; Watanabe, Yosikazu

36

Simple correction factor for laser speckle imaging of flow dynamics  

PubMed Central

One of the major constraints facing laser speckle imaging for blood-flow measurement is reliable measurement of the correlation time (?C) of the back-scattered light and, hence, the blood’s speed in blood vessels. In this Letter, we present a new model expression for integrated speckle contrast, which accounts not only for temporal integration but spatial integration, too, due to the finite size of the pixel of the CCD camera; as a result, we find that a correction factor should be introduced to the measured speckle contrast to properly determine ?C; otherwise, the measured blood’s speed is overestimated. Experimental results support our theoretical model. PMID:24487897

Ramirez-San-Juan, J. C.; Ramos-Garcia, R.; Martinez-Niconoff, G.; Choi, B.

2014-01-01

37

Production of element correction factors for thermoluminescent dosimeters  

SciTech Connect

Approximately 80 processors of personal dosimetry in the United States use thermoluminescent dosimeters (TLDs). Recent demands that dosimetry processors be able to measure radiation doses to within +/- 50% of the correct value have focused attention on the reproducibility of the TL elements within each TLD. The phosphors for these TLDs are manufactured by three companies. A dosimetry processor faces three options concerning the quality of the TL elements purchased; trust the supplier's quality control program, screen new TL elements and discard those that are extremely bad, or use element correction factors (ECFs). The first option results in dosimetry processors failing the +/- 50% accuracy requirement due to excessive variability among the TL elements. The second option still permits large precision errors that come close to the +/- 50% accuracy requirement. This paper advocates the third option and presents a 10-step procedure to produce ECFs. The procedure ensures that the ECFs represent only variations among the TL elements and not variations caused by stability problems with the TLD reader. Following is an example of ECF production for 3000 TLDs.

Plato, P.; Miklos, J.

1985-11-01

38

[Research on spectrum correction algorithm of temperature measurement system based on FBG].  

PubMed

In order to solve the problem that temperature sensor laying is complex and maintenance cost is high in the large-scale, multi-point real-time temperature monitoring process, the temperature monitoring system based on Fiber Bragg Grating was designed and developed. Using wavelength selectivity by optical fiber diffraction grating, a function of temperature and wavelength was established. Temperature of the measured position was inversed by calculating the wavelength variation through the optical fiber Bragg grating. Due to environmental, materials and other factors, the spectral distribution and temperature changes do not satisfy linear relationship. Therefore, designed the spectrum correction algorithm was designed, and function curve fitting of wavelength and temperature was completed with a degree of fitting greater than 99.7%. Experiments used FB136L-IAC-proof oven, LPT-200 diode, and 1 550 nm optical fiber to detect 20 to 280 degrees C temperature range of multi-point in real-time. The results show that when the temperature is changed by 1 degrees C, the corresponding center wavelength shifts about 0.04 nm to longer wavelengths. Compared with the test data from standard device, the error is less than +/- 0.3 degrees C. Meanwhile, the spectral correction algorithm was applied to the system to further improve the uniformity and accuracy of the temperature detection. Because the system uses fiber-optic sensor network, it has a strong anti-electromagnetic interference capability. The diffraction grating can achieve precise measurements, so it has big dynamic range and high accuracy. The innovation of the system is to ensure high-precision measurements, while still satisfy large-scale, multi-point, high anti-jamming capability of rapid laying, and has a strong practical value. PMID:25269282

Liu, Zhi-Chao; Yang, Jin-Hua; Wang, Gao

2014-07-01

39

Effects of temperature gradient correction of carbon dioxide absorbent on carbon dioxide absorption  

Microsoft Academic Search

Background. The effects of temperature gradients in CO2 absorbents on water content and CO2 absorption are not clear. We constructed a novel temperature gradient correction (TGC) canister, and investigated the effects of temperature gradient correction on the water content and longevity (time to exhaustion) of CO2 absorbent using a simulated anaesthesia circuit. Methods. Experiments were divided into two groups according

G. Hirabayashi; H. Uchino; T. Sagara; T. Kakinuma; Y. Ogihara; N. Ishii

2006-01-01

40

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

41

Design of a Boost Power Factor Correction Converter Using Optimization Techniques Sergio Busquets-Monge1  

E-print Network

correction, boost, electromagnetic interference, electromagnetic compatibility. Paper presented at PESC, June optimization, power factor correction, boost, electromagnetic interference, electromagnetic compatibility. I-end converter with an input electromagnetic interference filter. The system design variables are first

Lindner, Douglas K.

42

[Study on temperature correctional models of quantitative analysis with near infrared spectroscopy].  

PubMed

Effect of enviroment temperature on near infrared spectroscopic quantitative analysis was studied. The temperature correction model was calibrated with 45 wheat samples at different environment temperaturs and with the temperature as an external variable. The constant temperature model was calibated with 45 wheat samples at the same temperature. The predicted results of two models for the protein contents of wheat samples at different temperatures were compared. The results showed that the mean standard error of prediction (SEP) of the temperature correction model was 0.333, but the SEP of constant temperature (22 degrees C) model increased as the temperature difference enlarged, and the SEP is up to 0.602 when using this model at 4 degrees C. It was suggested that the temperature correctional model improves the analysis precision. PMID:16201365

Zhang, Jun; Chen, Hua-cai; Chen, Xing-dan

2005-06-01

43

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 false NOX intake-air humidity and temperature corrections...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.670 NOX intake-air humidity and temperature...

2012-07-01

44

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 false NOX intake-air humidity and temperature corrections...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.670 NOX intake-air humidity and temperature...

2011-07-01

45

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 false NOX intake-air humidity and temperature corrections...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.670 NOX intake-air humidity and temperature...

2010-07-01

46

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 false NOX intake-air humidity and temperature corrections...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.670 NOX intake-air humidity and temperature...

2013-07-01

47

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

DOEpatents

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.

Ianakiev, Kiril D. (Los Alamos, NM); Hsue, Sin Tao (Santa Fe, NM); Browne, Michael C. (Los Alamos, NM); Audia, Jeffrey M. (Abiquiu, NM)

2006-07-25

48

Lorentz-CPT violation, radiative corrections and finite temperature  

NASA Astrophysics Data System (ADS)

In this work we investigate the radiatively induced Chern-Simons-like terms in four-dimensions at zero and finite temperature. We use the approach of rationalizing the fermion propagator up to the leading order in the CPT-violating coupling b?. In this approach, we have shown that although the coefficient of Chern-Simons term can be found unambiguously in different regularization schemes at zero or finite temperature, it remains undetermined. We observe a correspondence among results obtained at finite and zero temperature.

Nascimento, Jose R.; Passos, Eduardo; Petrov, Albert Yu.; Brito, Francisco A.

2007-06-01

49

Biotic attrition from tropical forests correcting for truncated temperature niches  

E-print Network

Salem, NC 27109, USA Abstract Species migration in response to warming temperatures is expected to lead., 2002, 2005; Thomas et al., 2004; Beckage et al., 2008; Kelly & Goulden, 2008; Lenoir et al., 2008; Chen

Silman, Miles R.

50

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

SciTech Connect

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)

Talamo, A.; Gohar, Y. [Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL 60439 (United States); Bournos, V.; Fokov, Y.; Kiyavitskaya, H.; Routkovskaya, C. [Joint Inst. for Power and Nuclear Research-Sosny, 99 Academician A.K.Krasin Str, Minsk 220109 (Belarus)

2012-07-01

51

Correction  

NASA Astrophysics Data System (ADS)

Age and duration of Mississippi Valley type ore-mineralizing events: Correction Geology, v. 23, p. 233 236 (March 1995) An error has been discovered in the calculation of the estimate for the duration of a Mississippi Valley type (MVT) mineralization event. In the original paper, the rate of apparent polar wander (APW) for North America was expressed in degrees of drift per million years (8/m.y.) rather than in million years per degree of drift (m.y./8). This inversion resulted in an incorrect estimate for the time required to form a typical MVT ore deposit. The correct value for the rate of APW is 2.7 6 0.7 m.y./8 from the Lower Devonian to the Upper Triassic, based on locations of the eight reference paleopoles of Van der Voo (1993). The original equation is correct and is repeated as follows: 2(a1 2 - a1 3) × rate of APW 5 duration of mineralization. The revised estimate for the average length of time it takes to form an MVT ore deposit is 25.2 6 6.5 m.y. using the correct value for the an MVT ore deposit is 25.2 6 6.5 m.y. using the correct value for the rate of APW (Table 1). Note that the paleopole statistics for Central Tennessee have changed slightly from the original paper, incorpo-rating additional data. The updated pole position is at 111.98E, 50.58N (a1 2 = 4.08, a1 3 = 2.18, azimuth = 698) (Lewchuk and Symons, 1996).

1996-06-01

52

Beta and Gamma Correction Factors for the Eberline R0-20 Ionization Chamber Survey Instrument  

SciTech Connect

This technical document provides details of derived correction factors for the Eberline R0-20 survey meter, which uses an ionization chamber to measure ambient exposure rates. A thin end window allows the instrument to measure exposure rates from non-penetrating radiation (i.e., beta radiation). Correction factors are provided for contact measurements with beta and gamma disk sources, gamma beams and, finally, general area beta fields. Beta correction factors are based on the instrument's response to 204Tl, selected as the most conservative isotope for beta correction factors, as indicated in previous studies of similar instruments using 204Tl, 147Pm, and 90Sr(Y) isotopes (LANL 1982). Gamma correction factors are based on 137Cs, considered the predominant source of gamma radiation on the Hanford Site.

Johnson, Michelle L.; Rathbone, Bruce A.; Bratvold, Thomas E.

2001-08-10

53

Temperature Dependence of Factors Controlling Isoprene Emissions  

NASA Technical Reports Server (NTRS)

We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

2009-01-01

54

A simple and fast atmospheric correction for spaceborne remote sensing of surface temperature  

Microsoft Academic Search

Accurate surface temperature retrieval using thermal infrared observations from satellites is important for surface energy balance modeling; however it is difficult to achieve without proper correction for atmospheric effects. Typically the atmospheric correction is obtained from radiosonde profiles and a radiative transfer model (RTM). But rigorous RTM processing is impractical for routine continental scale modeling because of long computational times.

A. N French; J. M Norman; M. C Anderson

2003-01-01

55

Correction Factors for Reactions involving Quark-Antiquark Annihilation or Production  

E-print Network

In reactions with $q \\bar q$ production or $q\\bar q$ annihilation, initial- and final-state interactions give rise to large corrections to the lowest-order cross sections. We evaluate the correction factor first for low relative kinetic energies by studying the distortion of the relative wave function. We then follow the procedure of Schwinger to interpolate this result with the well-known perturbative QCD vertex correction factors at high energies, to obtain an explicit semi-empirical correction factor applicable to the whole range of energies. The correction factor predicts an enhancement for $q\\bar q$ in color-singlet states and a suppression for color-octet states, the effect increasing as the relative velocity decreases. Consequences on dilepton production in the quark-gluon plasma, the Drell-Yan process, and heavy quark production processes are discussed.

Lali Chatterjee; Cheuk-Yin Wong

1994-12-21

56

Weld pool penetration measurement using ultrasound with thermal gradient correction factors  

NASA Astrophysics Data System (ADS)

Weld penetration is critical to final weld performance. There are many techniques for determining surface parameters of weld pools but the transient nature of the pools, high temperatures and intense electromagnetic energy make direct measurement of the penetration of weld pools difficult. In order to determine weld pool penetration ultrasonically from below the weld pool it is necessary to compensate for the variation in the time of flight of the ultrasound wave due to temperature gradients. This requires both a precise understanding of the location and magnitude of the temperature gradients and the time of flight of ultrasound at the range of temperatures seen in the gradients. Given this information it is possible to develop a correction factor to an ultrasonic time of flight reading that accurately represents the actual penetration of a weld pool. This research examines the electroslag surfacing (ESS) processing of AISI 1005 low carbon steel clad onto a ductile iron substrate. The high temperature cladding on low temperature substrate provides a deep weld penetration. Ultrasonic time of flight measurements were made from a piezoelectric transducer on the backside of the substrate to the solid/liquid interface of the weld pool during welding. The speed of ultrasound over a range of temperatures was determined from furnace heated ductile iron substrates. The sample was stepped and contact piezoelectric methods used to determine time of flight. A finite element model was developed and analyzed to predict thermal gradients in the substrate around the weld pool. The model was correlated to thermocouple data of substrate heating during welding. The predicted thermal gradients and speed/temperature curves are combined with the time of flight measurement to determine the location of the solid/liquid weld interface. An automated seam tracking system for ESS was also developed. This system utilizes a line laser at right angles to the view of a CCD camera which illuminates the relief of the existing bead for the camera. Optimas software was used to locate the edge of the bead and determine the correct location for the weld head to overlap the existing bead.

Anderton, John Martin

57

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

ERIC Educational Resources Information Center

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…

Ellis, Johnica; McFadden, Cheryl; Colaric, Susan

2008-01-01

58

Cascaded multilevel inverter based STATCOM with power factor correction feature  

Microsoft Academic Search

The paper investigates the STATCOM system based on five-level cascaded inverter controlled using carrier-based pulse width modulation (CB-PWM) technique. In this work, the STATCOM is controlled to provide only the reactive power compensation at the point of common coupling (PCC) when an RL load is connected to the power system at different lagging power factors. The rotating switching scheme is

Law Kah Haw; Mohamed Dahidah; Norman Mariun

2011-01-01

59

Global analysis of proton elastic form factor data with two-photon exchange corrections  

SciTech Connect

We use the world's data on elastic electron-proton scattering and calculations of two-photon exchange effects to extract corrected values of the proton's electric and magnetic form factors over the full Q^2 range of the existing data. Our analysis combines the corrected Rosenbluth cross section and polarization transfer data, and is the first extraction of G_Ep and G_Mp including explicit two-photon exchange corrections and their associated uncertainties. In addition, we examine the angular dependence of the corrected cross sections, and discuss the possible nonlinearities of the cross section as a function of epsilon.

J. Arrington; W. Melnitchouk; J. A. Tjon

2007-09-01

60

Perturbation correction factors for cylindrical ionization chambers in high-energy electron beams.  

PubMed

The aim of the study was to evaluate the perturbation correction factors at a reference depth for cylindrical ionization chambers in high-energy electron beams by means of the EGSnrc Monte Carlo user code cavity. The cylindrical chambers used in this study were the Farmer-type of PTW30010, PTW30011, PTW30012, and PTW30013 models. We calculated the wall correction factor, P (wall), the cavity or electron fluence correction factor, P (cav), the stem correction factor, P (stem), the central electrode correction factor, P (cel), and the overall perturbation correction factor, P (Q), for each chamber. The calculated P (cav) values were higher by from 2 to 1% than those recommended by the IAEA-TRS-398 code of practice, in an energy range of 6-18 MeV. The P (wall) values almost agreed with the analytical calculation performed with IAEA-TRS-398. The P (cel) values agreed with those of Ma and Nahum, performed with IAEA-TRS-398. The P (stem) values were approximately 0.995 on average and were independent of the electron beam energy. P (stem) needs to be considered in future dosimetry protocols. The P (Q) values were higher from 1 to 2% than those of IAEA-TRS-398 in an energy range of 6-18 MeV. PMID:20821081

Ono, Takeshi; Araki, Fujio; Yoshiyama, Fumiaki

2010-07-01

61

Correction method of physical temperature variation for airborne double-antenna microwave radiometer  

NASA Astrophysics Data System (ADS)

In this paper, the principle of the Ka-band airborne double-antenna microwave radiometer (ADAMR) based on the autogain compensative and noise coupling techniques is reviewed firstly. The radiometer has been applied successfully to detect the atmospheric supercooled water content. Although the auto-gain compensative technique can compensate the gain fluctuation to keep the radiometer's stability by measuring the output variation of reference noise source, it also introduces measurement error caused by the physical temperature change of the reference noise source. For this reason, a temperature correction method for the output voltage of this radiometer is proposed. The corrected equations are derived by using the regression relationship between the measurement error and the physical temperature of the reference noise source. In order to demonstrate the feasibility of this method, the outdoor contrast experiment was carried out. For the 30° antenna channel, the RMSE of the two-point calibration method is 2.039K while the RMSE of the correction method is 0.718K. For the 90° antenna channel, the RMSE of the two-point calibration method is 2.113K while the RMSE of the correction method is 0.448K. The results prove that the correction method can effectively correct the output of the radiometers with the auto-gain compensative technique.

Sun, Jian; Zhao, Kai; Jiang, Tao; Gu, Lingjia

2014-09-01

62

Design of Charge Pump Power Factor Correction Circuit for 150W PT Power Converter  

Microsoft Academic Search

A charge pump power factor correction (CPPFC) circuit for PT power converter has been proposed according to the circuit topology and the features of PT. The main contributions are as follows: 1) The principle of continuous input current CPPFC circuit and the unity power factor condition have been analyzed; 2) The design method has been put forward and the parameters

Rui Zhang; Weiping Zhang; Yuanchao Liu

2009-01-01

63

Simple Digital-Controlled AC\\/DC Converter with Power Factor Correction for Universal Input Applications  

Microsoft Academic Search

A simple digital-controlled AC\\/DC converter with power factor correction for universal input applications is presented. The presented method provides the following features: (1). easy for digital implementation, (2). universal input applications, (3). high power factor, (4). fast dynamic response, (5). no need of circuit parameter in prior, (6). no need of input voltage sensor. The range of input voltage for

Ko-Yen Lee; Hsiang-Yu Hsu; Yen-shin Lai

2007-01-01

64

Statistical Correction of Air Temperature Forecasts for City and Road Weather Applications  

NASA Astrophysics Data System (ADS)

The method for statistical correction of air /road surface temperatures forecasts was developed based on analysis of long-term time-series of meteorological observations and forecasts (from HIgh Resolution Limited Area Model & Road Conditions Model; 3 km horizontal resolution). It has been tested for May-Aug 2012 & Oct 2012 - Mar 2013, respectively. The developed method is based mostly on forecasted meteorological parameters with a minimal inclusion of observations (covering only a pre-history period). Although the st iteration correction is based taking into account relevant temperature observations, but the further adjustment of air and road temperature forecasts is based purely on forecasted meteorological parameters. The method is model independent, e.g. it can be applied for temperature correction with other types of models having different horizontal resolutions. It is relatively fast due to application of the singular value decomposition method for matrix solution to find coefficients. Moreover, there is always a possibility for additional improvement due to extra tuning of the temperature forecasts for some locations (stations), and in particular, where for example, the MAEs are generally higher compared with others (see Gilet et al., 2014). For the city weather applications, new operationalized procedure for statistical correction of the air temperature forecasts has been elaborated and implemented for the HIRLAM-SKA model runs at 00, 06, 12, and 18 UTCs covering forecast lengths up to 48 hours. The procedure includes segments for extraction of observations and forecast data, assigning these to forecast lengths, statistical correction of temperature, one-&multi-days statistical evaluation of model performance, decision-making on using corrections by stations, interpolation, visualisation and storage/backup. Pre-operational air temperature correction runs were performed for the mainland Denmark since mid-April 2013 and shown good results. Tests also showed that the CPU time required for the operational procedure is relatively short (less than 15 minutes including a large time spent for interpolation). These also showed that in order to start correction of forecasts there is no need to have a long-term pre-historical data (containing forecasts and observations) and, at least, a couple of weeks will be sufficient when a new observational station is included and added to the forecast point. Note for the road weather application, the operationalization of the statistical correction of the road surface temperature forecasts (for the RWM system daily hourly runs covering forecast length up to 5 hours ahead) for the Danish road network (for about 400 road stations) was also implemented, and it is running in a test mode since Sep 2013. The method can also be applied for correction of the dew point temperature and wind speed (as a part of observations/ forecasts at synoptical stations), where these both meteorological parameters are parts of the proposed system of equations. The evaluation of the method performance for improvement of the wind speed forecasts is planned as well, with considering possibilities for the wind direction improvements (which is more complex due to multi-modal types of such data distribution). The method worked for the entire domain of mainland Denmark (tested for 60 synoptical and 395 road stations), and hence, it can be also applied for any geographical point within this domain, as through interpolation to about 100 cities' locations (for Danish national byvejr forecasts). Moreover, we can assume that the same method can be used in other geographical areas. The evaluation for other domains (with a focus on Greenland and Nordic countries) is planned. In addition, a similar approach might be also tested for statistical correction of concentrations of chemical species, but such approach will require additional elaboration and evaluation.

Mahura, Alexander; Petersen, Claus; Sass, Bent; Gilet, Nicolas

2014-05-01

65

Comparison between CARS and corrected thermocouple temperature measurements in a diffusion flame  

Microsoft Academic Search

Coherent anti-Stokes Raman spectroscopy (CARS) has been used to obtain radial temperature profiles in an axisymmetric methane diffusion flame. Temperatures were obtained from analysis of background-free nitrogen Q- and O-branch spectra. The spectra were analyzed with a nonlinear least-squares CARS fitting program and compared to measurements from radiation- and conduction-corrected thermocouples. Excellent agreement was obtained in regions of relatively constant

R. L. Farrow; P. L. Mattern; L. A. Rahn

1982-01-01

66

H A correction for sonic temperature errors resulting from flow acceleration and  

E-print Network

H A correction for sonic temperature errors resulting from flow acceleration and sensor head acceleration and sensor head distortion. Respectively, these additional terms produce an adjustment to sensible with the standard adjustment for the fluctuations of water vapour and sensor path deflection of -7.3 +/- 13.9 W m-2

67

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...

68

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

69

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

70

Calculation of the Pitot tube correction factor for Newtonian and non-Newtonian fluids.  

PubMed

This paper presents the numerical investigation performed to calculate the correction factor for Pitot tubes. The purely viscous non-Newtonian fluids with the power-law model constitutive equation were considered. It was shown that the power-law index, the Reynolds number, and the distance between the impact and static tubes have a major influence on the Pitot tube correction factor. The problem was solved for a wide range of these parameters. It was shown that employing Bernoulli's equation could lead to large errors, which depend on the magnitude of the kinetic energy and energy friction loss terms. A neural network model was used to correlate the correction factor of a Pitot tube as a function of these three parameters. This correlation is valid for most Newtonian, pseudoplastic, and dilatant fluids at low Reynolds number. PMID:14582876

Etemad, S Gh; Thibault, J; Hashemabadi, S H

2003-10-01

71

Abstract--A control structure for an interleaved power factor correction (PFC) rectifier with smart combination of analog and  

E-print Network

Abstract-- A control structure for an interleaved power factor correction (PFC) rectifier-digital control approach is verified by experimental results. Keywords: power factor correction rectifier, digital correction (PFC) rectifier is widely used as front-end stage for AC-DC switched-mode power supplies (SMPS

Paderborn, Universität

72

Correction factor for ablation algorithms used in corneal refractive surgery with gaussian-profile beams  

NASA Astrophysics Data System (ADS)

We provide a correction factor to be added in ablation algorithms when a Gaussian beam is used in photorefractive laser surgery. This factor, which quantifies the effect of pulse overlapping, depends on beam radius and spot size. We also deduce the expected post-surgical corneal radius and asphericity when considering this factor. Data on 141 eyes operated on LASIK (laser in situ keratomileusis) with a Gaussian profile show that the discrepancy between experimental and expected data on corneal power is significantly lower when using the correction factor. For an effective improvement of post-surgical visual quality, this factor should be applied in ablation algorithms that do not consider the effects of pulse overlapping with a Gaussian beam.

Jimenez, Jose Ramón; González Anera, Rosario; Jiménez del Barco, Luis; Hita, Enrique; Pérez-Ocón, Francisco

2005-01-01

73

BCS instability and finite temperature corrections to tachyon mass in intersecting D1-branes  

NASA Astrophysics Data System (ADS)

A holographic description of BCS superconductivity is given in [1]. This model was constructed by insertion of a pair of D8-branes on a D4-background. The spectrum of intersecting D8-branes has tachyonic modes indicating an instability which is identified with the BCS instability in superconductors. Our aim is to study the stability of the intersecting branes under finite temperature effects. Many of the technical aspects of this problem are captured by a simpler problem of two intersecting D1-branes on flat background. In the simplified set-up we compute the one-loop finite temperature corrections to the tree-level tachyon mass-squared-squared using the frame-work of SU(2) Yang-Mills theory in (1 + 1)-dimensions. We show that the one-loop two-point functions are ultraviolet finite due to cancellation of ultraviolet divergence between the amplitudes containing bosons and fermions in the loop. The amplitudes are found to be infrared divergent due to the presence of massless fields in the loops. We compute the finite temperature mass-squared correction to all the massless fields and use these temperature dependent masses-squared to compute the tachyonic mass-squared correction. We show numerically the existence of a transition temperature at which the effective mass-squared of the tree-level tachyons becomes zero, thereby stabilizing the brane configuration.

Chowdhury, Sudipto Paul; Sarkar, Swarnendu; Sathiapalan, B.

2014-09-01

74

New look at displacement factor and point of measurement corrections in ionization chamber dosimetry  

SciTech Connect

A new technique is presented for determination of the effective point of measurement when cavity ionization chambers are used to measure the absorbed dose due to ionizing radiation in a dense medium. An algorithm is derived relating the effective point of measurement to the displacement correction factor. This algorithm relates variations of the displacement factor to the radiation field gradient. The technique is applied to derive the magnitudes of the corrections for several chambers in a p(66)Be(49) neutron therapy beam. 30 references, 4 figures, 1 table.

Awschalom, M.; Rosenberg, I.; Ten Haken, R.K.

1983-01-01

75

Equivalence of computer codes for calculation of coincidence summing correction factors.  

PubMed

The aim of the study was to check for equivalence of computer codes that can perform calculations of true coincidence summing correction factors. All calculations were performed for a set of well-defined detector and sample parameters, without any reference to empirical data. For a p-type detector model the application of different codes resulted in satisfactory agreement in the calculated correction factors. For high-efficiency geometries in combination with an n-type detector and a radionuclide emitting abundant X-rays the results were scattered. PMID:24332343

Vidmar, T; Capogni, M; Hult, M; Hurtado, S; Kastlander, J; Lutter, G; Lépy, M-C; Martinkovi?, J; Ramebäck, H; Sima, O; Tzika, F; Vidmar, G

2014-05-01

76

Satellite microwave brightness temperature corrections for forest, lake fraction and atmospheric attenuation processes  

NASA Astrophysics Data System (ADS)

Passive microwave remote sensing retrievals of seasonal snow accumulation typically exploit the scattering behavior of snow to estimate the snow water equivalent or snow depth. Retrieval algorithms must also correct for atmospheric and forest attenuation as well as lake fraction effects that can modify the scattering behavior observed by a multi-frequency radiometer. Recent studies have demonstrated forest cover attenuation corrections and atmospheric attenuation reduction approaches but lake faction effects have not yet been corrected. This paper explores the radiometric response of snow under each of these attenuation features using the Advanced Microwave Scanning Radiometer - EOS brightness temperature record from 2002-2011. The study focuses on multi-frequency brightness temperature sensitivities to atmospheric transmission at different land elevations, and to attenuation by spatio-temperal forest biophysical structural characteristics, such as forest fraction and gap fraction. The study confirms previously identified approaches to minimizing attenuation effects. In addition, brightness temperature sensitivity to lake fraction is explored using a high spatial resolution global lake fraction data set. Whilst lake fraction is a key Earth surface variable, lake status is also an important parameter that determines whether the lower frequency emission is from a water or a lake ice emitting surface. In situ measurements from Canada are used to provide verification data on the lake status and identify a first order approach to correcting lake fraction effects.

Kelly, R. E.; Elliott, C.

2012-12-01

77

Bias correction of temperature produced by the Community Climate System Model using Artificial Neural Networks  

NASA Astrophysics Data System (ADS)

General Circulation Models (GCMs) are used to predict circulation and energy transfers between the atmosphere and the land. It is known that these models produce biased results that will have impact on their uses. This work proposes a new method for bias correction: the equidistant cumulative distribution function-artificial neural network (EDCDFANN) procedure. The method uses artificial neural networks (ANNs) as a surrogate model to estimate bias-corrected temperature, given an identification of the system derived from GCM models output variables. A two-layer feed forward neural network is trained with observations during a historical period and then the adjusted network can be used to predict bias-corrected temperature for future periods. To capture the extreme values this method is combined with the equidistant CDF matching method (EDCDF, Li et al. 2010). The proposed method is tested with the Community Climate System Model (CCSM3) outputs using air and skin temperature, specific humidity, shortwave and longwave radiation as inputs to the ANN. This method decreases the mean square error and increases the spatial correlation between the modeled temperature and the observed one. The results indicate the EDCDFANN has potential to remove the biases of the model outputs.

Moghim, S.; Hsu, K.; Bras, R. L.

2013-12-01

78

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

PubMed

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. PMID:18777925

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

2008-08-01

79

The perturbation correction factors for cylindrical ionization chambers in high-energy photon beams.  

PubMed

In this study, we calculated perturbation correction factors for cylindrical ionization chambers in high-energy photon beams by using Monte Carlo simulations. We modeled four Farmer-type cylindrical chambers with the EGSnrc/Cavity code and calculated the cavity or electron fluence correction factor, P (cav), the displacement correction factor, P (dis), the wall correction factor, P (wall), the stem correction factor, P (stem), the central electrode correction factor, P (cel), and the overall perturbation correction factor, P (Q). The calculated P (dis) values for PTW30010/30013 chambers were 0.9967 +/- 0.0017, 0.9983 +/- 0.0019, and 0.9980 +/- 0.0019, respectively, for (60)Co, 4 MV, and 10 MV photon beams. The value for a (60)Co beam was about 1.0% higher than the 0.988 value recommended by the IAEA TRS-398 protocol. The P (dis) values had a substantial discrepancy compared to those of IAEA TRS-398 and AAPM TG-51 at all photon energies. The P (wall) values were from 0.9994 +/- 0.0020 to 1.0031 +/- 0.0020 for PTW30010 and from 0.9961 +/- 0.0018 to 0.9991 +/- 0.0017 for PTW30011/30012, in the range of (60)Co-10 MV. The P (wall) values for PTW30011/30012 were around 0.3% lower than those of the IAEA TRS-398. Also, the chamber response with and without a 1 mm PMMA water-proofing sleeve agreed within their combined uncertainty. The calculated P (stem) values ranged from 0.9945 +/- 0.0014 to 0.9965 +/- 0.0014, but they are not considered in current dosimetry protocols. The values were no significant difference on beam qualities. P (cel) for a 1 mm aluminum electrode agreed within 0.3% with that of IAEA TRS-398. The overall perturbation factors agreed within 0.4% with those for IAEA TRS-398. PMID:20821090

Yoshiyama, Fumiaki; Araki, Fujio; Ono, Takeshi

2010-07-01

80

NOTE: Monte Carlo simulation of correction factors for IAEA TLD holders  

NASA Astrophysics Data System (ADS)

The IAEA standard thermoluminescent dosimeter (TLD) holder has been developed for the IAEA/WHO TLD postal dose program for audits of high-energy photon beams, and it is also employed by the ESTRO-QUALity assurance network (EQUAL) and several national TLD audit networks. Factors correcting for the influence of the holder on the TL signal under reference conditions have been calculated in the present work from Monte Carlo simulations with the PENELOPE code for 60Co ?-rays and 4, 6, 10, 15, 18 and 25 MV photon beams. The simulation results are around 0.2% smaller than measured factors reported in the literature, but well within the combined standard uncertainties. The present study supports the use of the experimentally obtained holder correction factors in the determination of the absorbed dose to water from the TL readings; the factors calculated by means of Monte Carlo simulations may be adopted for the cases where there are no measured data.

Hultqvist, Martha; Fernández-Varea, José M.; Izewska, Joanna

2010-03-01

81

Q-factor customized ablation profile for the correction of myopic astigmatism  

Microsoft Academic Search

PURPOSE: To compare the results of the Q-factor customized aspheric ablation profile with the wavefront-guided customized ablation pattern for the correction of myopic astigmatism. SETTING: Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland. METHODS: Thirty-five patients were enrolled in a controlled study in which the nondominant eye was treated with the Q-factor customized profile (custom-Q study group) and the dominant

Tobias Koller; Hans Peter Iseli; Farhad Hafezi; Michael Mrochen; Theo Seiler

2006-01-01

82

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

SciTech Connect

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.

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

2012-01-01

83

An active power factor correction technique for three-phase diode rectifiers  

Microsoft Academic Search

A novel active power factor correction method for power supplies with three-phase front-end diode rectifiers is proposed and analyzed. The implementation of this method requires the use of an additional single switch boost chopper. The combined front-end converter draws sinusoidal AC currents from the AC source with nearly unity input power factor while operating at a fixed switching frequency. It

A. R. Prasad; Phoivos D. Ziogas; Stefanos Manias

1991-01-01

84

An active power factor correction technique for three-phase diode rectifiers  

Microsoft Academic Search

A novel active power factor correction method for power supplies with three-phase front-end diode rectifiers is proposed and analyzed. The implementation of this method requires the use of an additional single-switch boost chopper. The combined front-end converter draws sinusoidal AC currents from the AC source with nearly unity input power factor while operating at a fixed switching frequency. It is

A. R. Prasad; P. D. Ziogas; S. Manias

1989-01-01

85

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

SciTech Connect

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.

Winterhalter, Wade

2011-09-01

86

A power factor corrected PMBLDCM drive for air-conditioner using bridge converter  

Microsoft Academic Search

This paper aims at a power factor corrected (PFC) buck bridge DC-DC converter for a permanent magnet brushless DC motor (PMBLDCM) for an air conditioner. This PFC converter is fed from a single-phase AC mains through a diode bridge rectifier (DBR) and connected to a voltage source inverter (VSI) feeding the PMBLDCM. The Speed of the proposed PMBLDCM drive is

Sanjeev Singh; Bhim Singh

2010-01-01

87

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

E-print Network

, power factor correction and harmonic elimination. The STATCOM model is developed in EMTP, and analytical reliability standards for the bulk power systems, in its report on "Reliability Considerations from characteristics and the operating condition values are input from the characteristic tests and from the simulation

Tolbert, Leon M.

88

A high performance single phase AC to DC rectifier with input power factor correction  

Microsoft Academic Search

A high performance single phase AC to DC rectifier with input power factor correction is proposed. The proposed approach has many advantages which include fewer semiconductor components, simplified control, high performance features and satisfaction of IEC 555 harmonic current standards. Simulation and experimental results obtained on a laboratory prototype are discussed

P. N. Enjeti; R. Martinez

1993-01-01

89

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

Microsoft Academic Search

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

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

2002-01-01

90

SCIAMACHY MONITORING FACTORS: OBSERVATION AND END-TO-END CORRECTION OF INSTRUMENT PERFORMANCE DEGRADATION  

E-print Network

and occultation geometry. To ensure the SCIAMACHY data quality over the life-time of the instrument, its with time [2]. Main degrading components are the mirrors in the optical path of the instrument. SCIAMACHYSCIAMACHY MONITORING FACTORS: OBSERVATION AND END-TO-END CORRECTION OF INSTRUMENT PERFORMANCE

Tilstra, Gijsbert

91

New, zero voltage switching, high frequency boost converter topology for power factor correction  

Microsoft Academic Search

This paper introduces a technique for combining zero-voltage-switching with boost converter technology to enable high frequency, high efficiency operation of the converter. The combination creates a new topology which is effective to meet the power factor correction and harmonic reduction requirements of new EMC standards. The unique topology provides limitation of the recovery current of the boost diode and uses

John A Bassett

1995-01-01

92

Power factor correction of an electrical drive system based on multiphase machines  

E-print Network

Power factor correction of an electrical drive system based on multiphase machines Khoudir MAROUANI on multiphase machines. Thus, the double-star induction machine is taken, as an example of multiphase machines is to maintain the PF of the power-winding, of the double star induction machine, in vicinity of unity whatever

Paris-Sud XI, Université de

93

Novel developments in the study of nonlinear phenomena in power factor correction circuits  

Microsoft Academic Search

Boost power factor correction (PFC) converter with average current mode control is a nonlinear system due to the effects of the multiplier and a large variation of the duty ratio. Although stability analysis must be studied depending on nonlinear model, most prior researches attempted to put some assumptions to force this nonlinear system to be linear. As a result the

Mohamed Orabi; Tamotsu Ninomiya; Chunfeng Jin

2002-01-01

94

Single-Stage Offline SEPIC Converter with Power Factor Correction to Drive High Brightness LEDs  

Microsoft Academic Search

An interleaved SEPIC converter with LED current dimmable and input power factor correction is proposed as a high performance driver for the high brightness white LEDs. The converter is controlled with voltage mode PWM and run in discontinuous conduction mode so that the inductor current follows the rectified input voltage. The critical design constraints and equations for both the power

Zhongming Ye; Fred Greenfeld; Zhixiang Liang

2009-01-01

95

Correction factor for continuous monitoring of wood smoke fine particulate matter  

PubMed Central

The US Environmental Protection Agency (EPA) has designated a handful of instruments as Federal Reference or Federal Equivalency Methods (FRM and FEM, respectively) for the monitoring of fine particulate matter (PM2.5). More commonly used for indoor exposure assessment studies are optical scanning devices such as the DustTrak (TSI) due to the their portability and affordability. It is recommended by the manufacturer of these instruments that a “correction factor” be applied when assessing source-specific conditions. In this study, DustTraks were collocated with multiple samplers in various environments in an effort to establish an indoor, wood smoke-source specific correction factor. The DustTrak was found to report PM2.5 levels on average 1.6 times higher than a filter based method in two indoor sampling programs. The DustTrak also reported indoor PM2.5 concentrations 1.7 times higher than a FRM sampler during a regional forest fire event. These real-world scenarios give a correction factor within a reasonable range of the results of a controlled laboratory experiment in which DustTraks reported PM2.5 approximately 2 times higher than a FEM. Our indoor wood smoke-specific correction factor of 1.65 will allow for DustTraks to be confidently used in quantifying PM2.5 exposures within indoor environments predominantly impacted by wood smoke.

McNamara, Marcy L.; Noonan, Curtis W.; Ward, Tony J.

2012-01-01

96

76 FR 19913 - Compliance Testing Procedures: Correction Factor for Room Air Conditioners  

Federal Register 2010, 2011, 2012, 2013

...a data correction factor in compliance testing procedures for room air conditioners...regulations governing DOE's compliance testing procedures at that time. The petition...using IMST-ART version 3.30 modeling software of five simulations, in each case...

2011-04-11

97

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

SciTech Connect

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.

Yoo, Soohaeng; Xantheas, Sotiris S.

2011-03-28

98

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

Microsoft Academic Search

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 ?18O values of bulk carbonate for diagenetic overprinting. Comparison of bulk carbonate and planktonic foraminiferal ?18O records from ODP site 677A indicates that the oxygen isotopic composition

Daniel P. Schrag; Donald J. DePaolo; Frank M. Richter

1995-01-01

99

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

NASA Astrophysics Data System (ADS)

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.

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

100

Short-wave near-infrared spectrometer for alcohol determination and temperature correction.  

PubMed

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 r(2) 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

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

2012-01-01

101

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

PubMed

The application of small photon fields in modern radiotherapy requires the determination of total scatter factors Scp or field factors ?(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 correction factor on the accelerator geometry for field sizes below 1 × 1 cm(2), i.e. on the beam spot size of the primary electrons hitting the target. This effect is especially pronounced for the ionization chambers. In conclusion, comparing all detectors, the unshielded diode PTW60017 is highly recommended for small field dosimetry, since its correction factor k(f(clin), f(msr))(Q(clin), Q(msr)) is closest to unity in small fields and mainly independent of the electron beam spot size. PMID:23514734

Czarnecki, D; Zink, K

2013-04-21

102

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

PubMed Central

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

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

2009-01-01

103

Linear Relation of Temperature and Density at Unit Compressibility Factor  

Microsoft Academic Search

A linear relation is found for the experimental temperatures and densities at which the compressibility factor PV\\/RT equals unity. The two characteristic constants of the relation are evaluated for 12 gases for which appropriate data exist. The pertinent range of temperature and density for gases is from the critical temperature to the Boyle temperature, and from zero density to over

Eugene M. Holleran

1967-01-01

104

Application of a correlation correction factor in a microarray cross-platform reproducibility study  

PubMed Central

Background Recent research examining cross-platform correlation of gene expression intensities has yielded mixed results. In this study, we demonstrate use of a correction factor for estimating cross-platform correlations. Results In this paper, three technical replicate microarrays were hybridized to each of three platforms. The three platforms were then analyzed to assess both intra- and cross-platform reproducibility. We present various methods for examining intra-platform reproducibility. We also examine cross-platform reproducibility using Pearson's correlation. Additionally, we previously developed a correction factor for Pearson's correlation which is applicable when X and Y are measured with error. Herein we demonstrate that correcting for measurement error by estimating the "disattenuated" correlation substantially improves cross-platform correlations. Conclusion When estimating cross-platform correlation, it is essential to thoroughly evaluate intra-platform reproducibility as a first step. In addition, since measurement error is present in microarray gene expression data, methods to correct for attenuation are useful in decreasing the bias in cross-platform correlation estimates. PMID:18005444

Archer, Kellie J; Dumur, Catherine I; Taylor, G Scott; Chaplin, Michael D; Guiseppi-Elie, Anthony; Grant, Geraldine; Ferreira-Gonzalez, Andrea; Garrett, Carleton T

2007-01-01

105

Nonequilibrium structure factor for conserved spin dynamics: Abrupt temperature increase  

NASA Astrophysics Data System (ADS)

We consider the nonequilibrium, elastic-scattering structure factor S(q,t) (q denotes the wave vector, t the time), for the Kawasaki spin-conserving kinetic Ising model of a one-dimensional system with nearest-neighbor interactions, initially in equilibrium at temperature TI, that is suddenly placed in contact with a heat bath at temperature TF, with TF>>TI. We present detailed results for the case of TF=?, for which we have succeeded in calculating the exact form of S(q,t). For finite TF, we present an approximation scheme for the higher-order nonequilibrium correlation functions that leads to closure of the hierarchy of equations of motion. The merits of this approximation are that (i) S(q,t) is guaranteed to satisfy an exact sum rule over the Brillouin zone (BZ) of wave vectors q, and (ii) S(q,t) evolves to the correct value in the long-time limit. For antiferromagnetic coupling, the structure factor, initially dominated by the Bragg peak associated with TI at the edge of the BZ, decays exponentially with time, e-t/?q while approximately preserving its shape in q space, since the lifetime ?q is nearly independent of q. Except near the center of the BZ, after the Bragg peak has decayed sufficiently, the dependence of S(q,t) on q can be characterized as though the spins rapidly quasiequilibrate to the equilibrium structure factor associated with TF, ?(q,TF), in that S(q,t)/?(q,TF) is independent of q, but is time dependent, slowly approaching unity as t-1/2 for large t. For q~=0 the initial form of S remains in effect until the value of t is of order q-2. For ferromagnetic coupling, the initial Bragg peak for q~=0 does not preserve its shape while decaying exponentially, since the lifetime ?q strongly depends on the wave-vector q, diverging as q-2 for q-->0, and, in particular, it is as though the spins for q~=0 remain ``frozen'' at TI. Analogous to the behavior for antiferromagnetic interactions, away from the center of the BZ, we find that S(q,t)/?(q,TF) is independent of q and is a function of t/tw, very slowly approaching unity. The characteristic ``waiting time'' tw is anomalously long, proportional to ?2, where ? is the equilibrium correlation length at temperature TI. This behavior of tw can be related to the random walk of domain boundaries.

Luscombe, James H.; Luban, Marshall

1996-09-01

106

Monte Carlo simulated correction factors for output factor measurement with the CyberKnife system—results for new detectors and correction factor dependence on measurement distance and detector orientation  

NASA Astrophysics Data System (ADS)

A previous study of the corrections needed for output factor measurements with the CyberKnife system has been extended to include new diode detectors (IBA SFD and Exradin D1V), an air filled microchamber (Exradin CC01) and a scintillation detector (Exradin W1). The dependence of the corrections on detector orientation (detector long axis parallel versus perpendicular to the beam axis) and source to detector distance (SDD) was evaluated for these new detectors and for those in our previous study. The new diodes are found to over-respond at the smallest (5 mm) field size by 2.5% (D1V) and 3.3% (SFD) at 800 mm SDD, while the CC01 under-responds by 7.4% at the same distance when oriented parallel to the beam. Corrections for all detectors tend to unity as field size increases. The W1 corrections are <0.5% at all field sizes. Microchamber correction factors increase substantially if the detector is oriented perpendicular to the beam (by up to 23% for the PTW 31014). Corrections also vary with SDD, with the largest variations seen for microchambers in the perpendicular orientation (up to 13% change at 650 mm SDD versus 800 mm) and smallest for diodes (?1% change at 650 mm versus 800 mm). The smallest and most stable corrections are found for diodes, liquid filled microchambers and scintillation detectors, therefore these should be preferred for small field output factor measurements. If air filled microchambers are used, then the parallel orientation should be preferred to the perpendicular, and care should be taken to use corrections appropriate to the measurement SDD.

Francescon, P.; Kilby, W.; Satariano, N.

2014-03-01

107

Monte Carlo simulated correction factors for output factor measurement with the CyberKnife system-results for new detectors and correction factor dependence on measurement distance and detector orientation.  

PubMed

A previous study of the corrections needed for output factor measurements with the CyberKnife system has been extended to include new diode detectors (IBA SFD and Exradin D1V), an air filled microchamber (Exradin CC01) and a scintillation detector (Exradin W1). The dependence of the corrections on detector orientation (detector long axis parallel versus perpendicular to the beam axis) and source to detector distance (SDD) was evaluated for these new detectors and for those in our previous study. The new diodes are found to over-respond at the smallest (5 mm) field size by 2.5% (D1V) and 3.3% (SFD) at 800 mm SDD, while the CC01 under-responds by 7.4% at the same distance when oriented parallel to the beam. Corrections for all detectors tend to unity as field size increases. The W1 corrections are <0.5% at all field sizes. Microchamber correction factors increase substantially if the detector is oriented perpendicular to the beam (by up to 23% for the PTW 31014). Corrections also vary with SDD, with the largest variations seen for microchambers in the perpendicular orientation (up to 13% change at 650 mm SDD versus 800 mm) and smallest for diodes (~1% change at 650 mm versus 800 mm). The smallest and most stable corrections are found for diodes, liquid filled microchambers and scintillation detectors, therefore these should be preferred for small field output factor measurements. If air filled microchambers are used, then the parallel orientation should be preferred to the perpendicular, and care should be taken to use corrections appropriate to the measurement SDD. PMID:24594929

Francescon, P; Kilby, W; Satariano, N

2014-03-21

108

A new high performance AC to DC rectifier with input power factor correction and harmonic reduction capacity  

E-print Network

, this thesis examines the cause and effects of low power factor and harmonic current in single phase rectifiers; provides a thorough review of previous correction techniques; and presents a new approach for ac to dc rectification with input power factor...

Martinez, Roberto

2012-06-07

109

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

110

A high-performance single-phase rectifier with input power factor correction  

Microsoft Academic Search

In this paper, a high-performance single-phase AC-to-DC rectifier with input power factor correction is proposed. The proposed approach has many advantages, including fewer semiconductor components, simplified control, and high-performance features, and satisfies IEC 555 harmonic current standards. Simulation and experimental results obtained on a laboratory prototype are discussed. A hybrid power module of the proposed approach is also shown

Roberto Martinez; Prasad N. Enjeti

1996-01-01

111

Source localization corrections for airborne acoustic platforms based on a climatological assessment of temperature and wind velocity profiles  

NASA Astrophysics Data System (ADS)

Acoustic sensors are being employed on airborne platforms, such as Persistent Threat Detection System (PTDS) and Persistent Ground Surveillance System (PGSS), for source localization. Under certain atmospheric conditions, airborne sensors oer a distinct advantage over ground sensors. The performance of both ground and airborne sensors is aected by environmental factors, such as atmospheric turbulence and wind and temperature proles. For airborne sensors, the eects of refraction must be accounted for in order to determine the source coordinates. Such a method for ground-to-air applications has been developed and is further rened here. Ideally, knowledge of the exact atmospheric proles will allow for the most accurate mitigation of refractive eects. However, acoustic sensors deployed in theater are rarely supported by atmospheric sensing systems that retrieve real-time temperature and wind elds. Atmospheric conditions evolve through seasons, time of day, and are strongly location dependent. Therefore, the development of an atmospheric proles database based on a long time series climatological assessment will provide knowledge for use in physics-based bearing estimation algorithms, where otherwise no correction would have been performed. Long term atmospheric data sets from weather modeling systems are used for a climatological assessment of the refraction corrections and localization errors over selected sites.

Ostashev, Vladimir E.; Cheinet, Sylvain; Collier, Sandra L.; Reiff, Christian; Ligon, David A.; Wilson, D. Keith; Noble, John M.; Alberts, W. C. Kirkpatrick, II

2012-06-01

112

Model atmospheres broad-band colors, bolometric corrections and temperature calibrations for O - M stars  

NASA Astrophysics Data System (ADS)

Broad band colors and bolometric corrections in the Johnson-Cousins-Glass system (Bessell, 1990; Bessell & Brett, 1988) have been computed from synthetic spectra from new model atmospheres of Kurucz (1995a), Castelli (1997), Plez, Brett & Nordlund (1992), Plez (1995-97), and Brett (1995a,b). These atmospheres are representative of larger grids that are currently being completed. We discuss differences between the different grids and compare theoretical color-temperature relations and the fundamental color temperature relations derived from: (a) the infrared-flux method (IRFM) for A-K stars (Blackwell & Lynas-Gray 1994; Alonso et al. 1996) and M dwarfs (Tsuji et al. 1996a); (b) lunar occultations (Ridgway et al. 1980) and (c) Michelson interferometry (Di Benedetto & Rabbia 1987; Dyck et al. 1996; Perrin et al. 1997) for K-M giants, and (d) eclipsing binaries for M dwarfs. We also compare color - color relations and color - bolometric correction relations and find good agreement except for a few colors. The more realistic fluxes and spectra of the new model grids should enable accurate population synthesis models to be derived and permit the ready calibration of non-standard photometric passbands. As well, the theoretical bolometric corrections and temperature - color relations will permit reliable transformation from observed color magnitude diagrams to theoretical HR diagrams. Tables 1-6 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

Bessell, M. S.; Castelli, F.; Plez, B.

1998-05-01

113

Nuclear recoil correction to the g factor of boron-like argon  

E-print Network

The nuclear recoil effect to the g factor of boron-like ions is investigated. The one-photon-exchange correction to the nuclear recoil effect is calculated in the non-relativistic approximation for the nuclear recoil operator and in the Breit approximation for the interelectronic-interaction operator. The screening potential is employed to estimate the higher-order contributions. The updated g-factor values are presented for the ground 2P_1/2 and first excited 2P_3/2 states of B-like argon 40^Ar^13+, which are presently being measured by the ARTEMIS group at GSI.

Shchepetnov, Arseniy A; Volotka, Andrey V; Shabaev, Vladimir M; Tupitsyn, Ilya I; Plunien, Guenter

2014-01-01

114

Parental weight (mis)perceptions: factors influencing parents' ability to correctly categorise their child's weight status.  

PubMed

This study investigates parents' ability to correctly classify their child's weight status. The influence of parent and child socio-demographic and lifestyle factors on parental misclassification of their child's weight status is explored. A representative sample of Irish children (aged 5-12 (n = 596) years, aged 13-17 years (n = 441)) and their parents (n = 1885) were recruited to participate in a national dietary survey. Parental perceptions of their child's weight and their own weight were measured. Anthropometric measurements (weight and height) were objectively measured for parents and children. Body Mass Index (BMI) scores were derived and categorised as normal, overweight or obese using standard references. Over 80% of parents of overweight boys and 79.3% of parents of overweight girls reported their child's weight was fine for his/her height and age. Furthermore, 44.4% of parents of obese boys and 45.3% of parents of obese girls felt their child's weight was fine for their height and age. Parents were significantly less likely to be correct about their sons' weight status and more likely to be correct the older the child. Parents were over 86% less likely to be correct about their child's weight if their child was overweight and approximately 59% less likely to be correct if the child was obese, compared to parents of normal weight children. This research suggests that parents are failing to recognise overweight and obesity in their children with factors such as parental weight status, child's age and gender influencing this. PMID:22139047

Hudson, Eibhlin; McGloin, Aileen; McConnon, Aine

2012-12-01

115

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

PubMed

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. PMID:23464237

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

2013-02-01

116

Temperature gradient mechanism: Overview of the multiple pass controlling factors  

NASA Astrophysics Data System (ADS)

Laser forming offers the industrial promise of controlled shaping of metallic and non-metallic components for prototyping, the correction of design shape or distortion and precision adjustment applications. To date there has been a considerable amount of work carried out on two-dimensional laser forming, using multi-pass straight line scan strategies to produce a reasonably controlled bend angle in a number of materials, including aerospace alloys. A key area, however, where there is a limited understanding, is the variation in bend angle per pass during multi-pass Temperature Gradient Mechanism (TGM) based laser forming along a single irradiation track, in particular the decrease in bend angle per pass after many irradiations for a given set of process parameters. The research presented in this paper through empirical data and numerical simulation using Comsol MultiPhysics of the multi-pass laser forming of sheet mild steel, Ti6Al4V and AA5251 by CO 2 laser offers a novel coherent picture of the key influencing factors and at which point in the bend evolution each is dominant.

Edwardson, S. P.; Griffiths, J.; Dearden, G.; Watkins, K. G.

117

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

NASA Astrophysics Data System (ADS)

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.

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

118

Monte Carlo and deterministic calculation of the Bell and Glasstone spatial correction factor  

NASA Astrophysics Data System (ADS)

The Bell and Glasstone correction factor is used in subcritical assembly pulsed neutron source experiments to correct the spatial dependency of the measured reactivity on the detector position. The correction factor is defined as the ratio between the reactivity obtained by computer codes in criticality mode and that obtained by computer codes in source mode. In the area method, the reactivity (in dollar units) of a subcritical assembly is given by the ratio between the prompt and the delayed areas; these areas are obtained by integrating the detector reaction rate over the pulse period. This work illustrates different methods to calculate the Bell and Glasstone spatial correction factor using both Monte Carlo (MCNPX) and deterministic (PARTISN) computer codes. The different calculation methods include: (1) the one-simulation dynamic method (which has been applied by MCNPX computer simulations); (2) the two-simulation static method (which has been applied by both MCNPX and PARTISN computer simulations); (3) the one-simulation static method (which has been applied by MCNPX computer simulations). In the one-simulation dynamic method: (1) the external neutron source is time dependent; (2) the detector reaction rate is obtained from a single pulse and it is superimposed until the delayed neutron contribution reaches the asymptotic value; (3) the prompt area is obtained as the difference between the total and delayed areas. In the two-simulation static method: (1) the external neutron source is time independent; (2) the total and prompt areas are obtained by two separate computer simulations (one with and the other without delayed neutrons); (3) the delayed area is obtained as the difference between the total and prompt areas. In the one-simulation static method, first introduced in this study, the prompt and delayed areas are tallied in the same MCNPX simulation, which halves the computing time and reduces the statistical error relative to the two-simulation static method.

Talamo, Alberto; Zhong, Zhaopeng; Gohar, Yousry

2012-09-01

119

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

120

Planar imaging quantification using 3D attenuation correction data and Monte Carlo simulated buildup factors  

NASA Astrophysics Data System (ADS)

A new method to correct for attenuation and the buildup of scatter in planar imaging quantification is presented. The method is based on the combined use of 3D density information provided by computed tomography to correct for attenuation and the application of Monte Carlo simulated buildup factors to correct for buildup in the projection pixels. CT and nuclear medicine images were obtained for a purpose-built nonhomogeneous phantom that models the human anatomy in the thoracic and abdominal regions. The CT transverse slices of the phantom were converted to a set of consecutive density maps. An algorithm was developed that projects the 3D information contained in the set of density maps to create opposing pairs of accurate 2D correction maps that were subsequently applied to planar images acquired from a dual-head gamma camera. A comparison of results obtained by the new method and the geometric mean approach based on published techniques is presented for some of the source arrangements used. Excellent results were obtained for various source - phantom configurations used to evaluate the method. Activity quantification of a line source at most locations in the nonhomogeneous phantom produced errors of less than 2%. Additionally, knowledge of the actual source depth is not required for accurate activity quantification. Quantification of volume sources placed in foam, Perspex and aluminium produced errors of less than 7% for the abdominal and thoracic configurations of the phantom.

Miller, Collie; Filipow, Larry; Jackson, Stuart; Riauka, Terence

1996-08-01

121

Correction factors for boundary diffusion in reaction-diffusion master equations  

NASA Astrophysics Data System (ADS)

The reaction-diffusion master equation (RDME) has been widely used to model stochastic chemical kinetics in space and time. In recent years, RDME-based trajectorial approaches have become increasingly popular. They have been shown to capture spatial detail at moderate computational costs, as compared to fully resolved particle-based methods. However, finding an appropriate choice for the discretization length scale is essential for building a reasonable RDME model. Moreover, it has been recently shown [R. Erban and S. J. Chapman, Phys. Biol. 4, 16 (2007); R. Erban and S. J. Chapman, Phys. Biol. 6, 46001 (2009); D. Fange, O. G. Berg, P. Sjöberg, and J. Elf, Proc. Natl. Acad. Sci. U.S.A. 107, 46 (2010)] that the reaction rates commonly used in RDMEs have to be carefully reassessed when considering reactive boundary conditions or binary reactions, in order to avoid inaccurate - and possibly unphysical - results. In this paper, we present an alternative approach for deriving correction factors in RDME models with reactive or semi-permeable boundaries. Such a correction factor is obtained by solving a closed set of equations based on the moments at steady state, as opposed to modifying probabilities for absorption or reflection. Lastly, we briefly discuss existing correction mechanisms for bimolecular reaction rates both in the limit of fast and slow diffusion, and argue why our method could also be applied for such purpose.

Leier, Andre; Marquez-Lago, Tatiana T.

2011-10-01

122

Correction factors for boundary diffusion in reaction-diffusion master equations.  

PubMed

The reaction-diffusion master equation (RDME) has been widely used to model stochastic chemical kinetics in space and time. In recent years, RDME-based trajectorial approaches have become increasingly popular. They have been shown to capture spatial detail at moderate computational costs, as compared to fully resolved particle-based methods. However, finding an appropriate choice for the discretization length scale is essential for building a reasonable RDME model. Moreover, it has been recently shown [R. Erban and S. J. Chapman, Phys. Biol. 4, 16 (2007); R. Erban and S. J. Chapman, Phys. Biol. 6, 46001 (2009); D. Fange, O. G. Berg, P. Sjo?berg, and J. Elf, Proc. Natl. Acad. Sci. U.S.A. 107, 46 (2010)] that the reaction rates commonly used in RDMEs have to be carefully reassessed when considering reactive boundary conditions or binary reactions, in order to avoid inaccurate--and possibly unphysical--results. In this paper, we present an alternative approach for deriving correction factors in RDME models with reactive or semi-permeable boundaries. Such a correction factor is obtained by solving a closed set of equations based on the moments at steady state, as opposed to modifying probabilities for absorption or reflection. Lastly, we briefly discuss existing correction mechanisms for bimolecular reaction rates both in the limit of fast and slow diffusion, and argue why our method could also be applied for such purpose. PMID:21992284

Leier, Andre; Marquez-Lago, Tatiana T

2011-10-01

123

Harmonic measurements, analysis, and power factor correction in a modern steel manufacturing facility  

SciTech Connect

Maximizing electric power transfer directly affects the productivity of an electric arc furnace operation. Arc furnaces and rolling mill loads operate at power factors that result in penalty charges and lower bus voltages. In addition, the nonlinear characteristics of the furnace arcs and rolling mill drives generate significant harmonic currents that flow through the plant and utility power system. These harmonic currents cause system voltage distortion and power loss in the system, and can interact with power factor correction capacitor banks leading to equipment failures. This paper presents the analytical technique used to correct power factor in a modern steel manufacturing facility. The study included field measurements, harmonic analysis, and filter design work to reduce the amount of harmonic distortion in the plant. The modeling of arc furnaces and rolling mills for a harmonic analysis study is also discussed. The solutions recommended in this paper to increase power factor and reduce harmonics can be applied to other steel manufacturing facilities to improve power quality and therefore plant productivity.

Andrews, D. [North Star Steel, Beaumont, TX (United States). Dept. of Plant Engineering] [North Star Steel, Beaumont, TX (United States). Dept. of Plant Engineering; Bishop, M.T.; Witte, J.F. [Cooper Power Systems, Franksville, WI (United States). Systems Engineering Group] [Cooper Power Systems, Franksville, WI (United States). Systems Engineering Group

1996-05-01

124

Monte Carlo calculations of correction factors for plastic phantoms in clinical photon and electron beam dosimetry  

SciTech Connect

The purpose of this study is to calculate correction factors for plastic water (PW) and plastic water diagnostic-therapy (PWDT) phantoms in clinical photon and electron beam dosimetry using the EGSnrc Monte Carlo code system. A water-to-plastic ionization conversion factor k{sub pl} for PW and PWDT was computed for several commonly used Farmer-type ionization chambers with different wall materials in the range of 4-18 MV photon beams. For electron beams, a depth-scaling factor c{sub pl} and a chamber-dependent fluence correction factor h{sub pl} for both phantoms were also calculated in combination with NACP-02 and Roos plane-parallel ionization chambers in the range of 4-18 MeV. The h{sub pl} values for the plane-parallel chambers were evaluated from the electron fluence correction factor {phi}{sub pl}{sup w} and wall correction factors P{sub wall,w} and P{sub wall,pl} for a combination of water or plastic materials. The calculated k{sub pl} and h{sub pl} values were verified by comparison with the measured values. A set of k{sub pl} values computed for the Farmer-type chambers was equal to unity within 0.5% for PW and PWDT in photon beams. The k{sub pl} values also agreed within their combined uncertainty with the measured data. For electron beams, the c{sub pl} values computed for PW and PWDT were from 0.998 to 1.000 and from 0.992 to 0.997, respectively, in the range of 4-18 MeV. The {phi}{sub pl}{sup w} values for PW and PWDT were from 0.998 to 1.001 and from 1.004 to 1.001, respectively, at a reference depth in the range of 4-18 MeV. The difference in P{sub wall} between water and plastic materials for the plane-parallel chambers was 0.8% at a maximum. Finally, h{sub pl} values evaluated for plastic materials were equal to unity within 0.6% for NACP-02 and Roos chambers. The h{sub pl} values also agreed within their combined uncertainty with the measured data. The absorbed dose to water from ionization chamber measurements in PW and PWDT plastic materials corresponds to that in water within 1%. Both phantoms can thus be used as a substitute for water for photon and electron dosimetry.

Araki, Fujio; Hanyu, Yuji; Fukuoka, Miyoko; Matsumoto, Kenji; Okumura, Masahiko; Oguchi, Hiroshi [Department of Radiological Technology, Kumamoto University School of Health Sciences, 4-24-1, Kuhonji, Kumamoto, 862-0976 (Japan); Division of Radiation Oncology, Tokyo Women's Medical University Hospital, Tokyo, 162-8666 (Japan); Department of Central Radiology, Kinki University Hospital, Osaka, 589-8511 (Japan); Department of Central Radiology, Shinshu University Hospital, Matsumoto, 390-8621 (Japan)

2009-07-15

125

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

NASA Technical Reports Server (NTRS)

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.

Blankenship, Clay; Zavodsky, Brad; Blackwell, William

2014-01-01

126

Correction factors for the determination of oxygen in silicon by IR spectrometry  

SciTech Connect

In order to achieve a high multilaboratory precision in measuring the oxygen content in CZ silicon slices and wafers by means of IR absorption spectroscopy various deviations from ideal measurement conditions are discussed and correction methods are presented. The main sources for measurement errors exceeding {plus minus} 1% standard deviation are: the radiation scattering at rough wafer reverse sides, the sample temperature during the measurement, the free carrier absorption if the carrier concentration exceeds 10{sup 15} cm{sup {minus} 3}, and the residual oxygen concentration in the reference sample if this consists of a common FZ silicon material. Less important are thickness deviations between sample and reference, spectral resolution, and instrumental errors for modern spectrometers. After applying all corrections, a multilaboratory precision in dispersive spectrometers of {le} + {minus} 1 and {le} + {minus} 2.5% is expected for both sides polished 2 mm thick silicon slices and one-side polished silicon wafers, respectively.

Schomann, F.; Graff, K. (Telefunken Electronic, D-7100 Heilbronn (DE))

1989-07-01

127

Gradient corrections to the kinetic energy density functional of a two-dimensional Fermi gas at finite temperature  

E-print Network

We examine the leading order semiclassical gradient corrections to the non-interacting kinetic energy density functional of a two dimensional Fermi gas by applying the extended Thomas-Fermi theory at finite temperature. We find a non-zero von Weizs\\"acker-like gradient correction, which in the high-temperature limit, goes over to the familiar functional form $(\\hbar^2/24m) (\

Brandon P. van Zyl; K. Berkane; K Bencheikh; A. Farrell

2010-12-01

128

Factor A (pH, 4-9) Factor B (temperature, 20C 37C)  

E-print Network

® Factor A (pH, 4-9) Factor B (temperature, 20C ­ 37C) Factor C (dissolved oxygen, 0% - 100%) 20 production in fermentation set up (such as temperature, dissolved oxygen, or pH for instance). Central

Strynadka, Natalie

129

Burnout among corrections-based drug treatment staff: impact of individual and organizational factors.  

PubMed

As a result of limited budgets, many treatment programs are forced to operate for extended periods at or beyond their capacity. The resulting pressure and stress on treatment staff can be taxing and lead to serious problems, including job burnout. Although the concept of burnout within other social service professions has been broadly researched, less attention has been given to burnout among drug abuse treatment staff, especially among corrections-based drug treatment staff. The goal of this article is to extend this area of research by exploring the impact of individual factors and organizational factors on burnout. Findings revealed that although a number of factors were related to staff burnout, younger counselor age, lower adaptability, poorer clarity of agency mission, and higher stress were most significant. Ways in which treatment programs might address these issues affecting staff burnout are discussed. PMID:17615435

Garner, Bryan R; Knight, Kevin; Simpson, D Dwayne

2007-10-01

130

Magnetic field effect on quantum corrections to the low-temperature conductivity in metallic perovskite oxides  

NASA Astrophysics Data System (ADS)

The transport and magnetotransport properties of the metallic and ferromagnetic SrRu O3 (SRO) and the metallic and paramagnetic LaNi O3 (LNO) epitaxial thin films have been investigated in fields up to 55 T at temperatures down to 1.8 K . At low temperatures both samples display a well-defined resistivity minimum. We argue that this behavior is due to the increasing relevance of quantum corrections to the conductivity (QCC) as temperature is lowered; this effect being particularly relevant in these oxides due to their short mean free path. However, it is not straightforward to discriminate between contributions of weak localization and renormalization of electron-electron interactions to the QCC through temperature dependence alone. We have taken advantage of the distinct effect of a magnetic field on both mechanisms to demonstrate that in ferromagnetic SRO the weak-localization contribution is suppressed by the large internal field leaving only renormalized electron-electron interactions, whereas in the nonmagnetic LNO thin films the weak-localization term is relevant.

Herranz, G.; Sánchez, F.; Fontcuberta, J.; Laukhin, V.; Galibert, J.; García-Cuenca, M. V.; Ferrater, C.; Varela, M.

2005-07-01

131

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

PubMed

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. PMID:11771630

Taylor, M J; Heaton, R K

2001-11-01

132

Low-Temperature Thermoelectric Power Factor Enhancement by Controlling  

E-print Network

Low-Temperature Thermoelectric Power Factor Enhancement by Controlling Nanoparticle Size nanoparticles inside a host matrix on the thermoelectric properties. This takes into account electron multiple nanoparticles compared to the conventional shallow impurities is quantified. At the optimum thermoelectric power

133

Succinate and artificial maintenance of normal body temperature synergistically correct lethal disorders in thiopental coma rat  

Microsoft Academic Search

Under modeling of thiopental coma influence of sodium succinate and (or) external warming for the support of normal body temperature (isothermal regimen) on the gas exchange, blood gas content, acid–base status and survival rate was studied in rats. In the absence of therapy hypothermia was developed (?9.4°C), O2 consumption decreased by a factor 5, oxygenation of arterial blood (pO2) did

Jury Ju. Ivnitsky; Vladimir L. Rejniuk; Timur V. Schäfer; Vladimir N. Malakhovsky

2006-01-01

134

Temperature and precipitation as limiting factors in ecosystems  

NSDL National Science Digital Library

This classroom activity is aimed at an understanding of different ecosystems by understanding the influence of temperature and precipitation. Students correlate graphs of vegetation vigor with those of temperature and precipitation data for four diverse ecosystems, ranging from near-equatorial to polar, and spanning both hemispheres to determine which climatic factor is limiting growth.

Project, Globe

135

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

136

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

NASA Astrophysics Data System (ADS)

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.

Collell, Julien; Galliero, Guillaume

2014-05-01

137

Correction factors for the INER-improved free-air ionization chambers calculated with the Monte Carlo method.  

PubMed

Monte Carlo method was used to simulate the correction factors for electron loss and scattered photons for two improved cylindrical free-air ionization chambers (FACs) constructed at the Institute of Nuclear Energy Research (INER, Taiwan). The method is based on weighting correction factors for mono-energetic photons with X-ray spectra. The newly obtained correction factors for the medium-energy free-air chamber were compared with the current values, which were based on a least-squares fit to experimental data published in the NBS Handbook 64 [Wyckoff, H.O., Attix, F.H., 1969. Design of free-air ionization chambers. National Bureau Standards Handbook, No. 64. US Government Printing Office, Washington, DC, pp. 1-16; Chen, W.L., Su, S.H., Su, L.L., Hwang, W.S., 1999. Improved free-air ionization chamber for the measurement of X-rays. Metrologia 36, 19-24]. The comparison results showed the agreement between the Monte Carlo method and experimental data is within 0.22%. In addition, mono-energetic correction factors for the low-energy free-air chamber were calculated. Average correction factors were then derived for measured and theoretical X-ray spectra at 30-50 kVp. Although the measured and calculated spectra differ slightly, the resulting differences in the derived correction factors are less than 0.02%. PMID:16427292

Lin, Uei-Tyng; Chu, Chien-Hau

2006-05-01

138

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

NASA Technical Reports Server (NTRS)

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.

Blakenship, Clay; Zavodsky, Bradley; Blackwell, William

2014-01-01

139

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

PubMed

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. PMID:23652238

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

2013-01-01

140

Control of power factor correcting boost converter without instantaneous measurement of input current  

SciTech Connect

This paper proposes a new control method for the constant-frequency control of power factor correcting boost converter using a sinewave template modulated PWM signal which eliminates the need for instantaneous measurement of the line current for the switching control of the boost converter. The control strategy is based on the notion that the line current can be forced to trace a deterministic waveform such as a sinusoid by considering the implicit model of the sinewave in the boost converter controller structure. The modulating sinewave template is generated using the line voltage, the boost converter output voltage and the load current. The paper provides the analysis and the design of the controller and presents simulation and implementation results to demonstrate its effectiveness.

Sivakumar, S.; Gudelewicz, R. [KB Electronics Ltd., Bedford, Nova Scotia (Canada)] [KB Electronics Ltd., Bedford, Nova Scotia (Canada); Natarajan, K. [Lakehead Univ., Thunder Bay, Ontario (Canada). Dept. of Electrical Engineering] [Lakehead Univ., Thunder Bay, Ontario (Canada). Dept. of Electrical Engineering

1995-07-01

141

Determination of correction factors for alpha activity measurements in the environment (conditions of high dust loading).  

PubMed

Within the framework of a French national monitoring program to survey the man-made radioactivity in the environment, several power plants and research facilities on the territory use environmental air monitors for unwanted releases of radioactive aerosols. High sensitivity and lack of false alarms are all important for environmental air monitors. The project aims to conduct investigations to improve operation of environmental air monitors, particularly under conditions where a lot of non-radioactive dust may be deposited on the filters (conditions of high dust loading). The dust may increase the frequency with which filters must be changed and can lead to an underestimation of the real activity. This underestimation is due to deteriorated alpha energy resolution and response specificity to the radionuclides of interest. In this study, our objective was to find experimental correction factors for the degraded activity measurements taking into account the alpha absorption in the dust loading. PMID:21138925

Geryes, Tony; Monsanglant-Louvet, Céline

2011-03-01

142

Next-to-leading-order corrections to the {gamma}* impact factor: First numerical results for the real corrections to {gamma}{sub L}*  

SciTech Connect

We analytically perform the transverse momentum integrations in the real corrections to the longitudinal {gamma}{sub L}* impact factor. The resulting integrals are Feynman parameter integrals, and we provide a MATHEMATICA file which contains the integrands. The remaining integrals are carried out numerically. We perform a numerical test, and we compute those parts of the impact factor which depend upon the energy scale s{sub 0}: They are found to be negative and, with decreasing values of s{sub 0}, their absolute value increases.

Bartels, J. [II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Kyrieleis, A. [Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)

2004-12-01

143

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

SciTech Connect

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 reconstruction pre-processing, where an algorithm detects and discards frames that would lead to inaccurate feature matching, camera pose estimation degeneracies or mathematical instability in structure computation based on a residual error comparison between two different match motion models. The presented algorithms were designed for aerial video but have been proven to work across different scene types and camera motions, and for both real and synthetic scenes.

Hess-Flores, M

2011-11-10

144

Monte Carlo simulated correction factors for machine specific reference field dose calibration and output factor measurement using fixed and iris collimators on the CyberKnife system.  

PubMed

Monte Carlo (MC) simulation of dose to water and dose to detector has been used to calculate the correction factors needed for dose calibration and output factor measurements on the CyberKnife system. Reference field ionization chambers simulated were the PTW 30006, Exradin A12, and NE 2571 Farmer chambers, and small volume chambers PTW 31014 and 31010. Correction factors for Farmer chambers were found to be 0.7%-0.9% larger than those determined from TRS-398 due mainly to the dose gradient across the chamber cavity. For one microchamber where comparison was possible, the factor was 0.5% lower than TRS-398 which is consistent with previous MC simulations of flattening filter free Linacs. Output factor detectors simulated were diode models PTW 60008, 60012, 60017, 60018, Sun Nuclear edge detector, air-filled microchambers Exradin A16 and PTW 31014, and liquid-filled microchamber PTW 31018 microLion. Factors were generated for both fixed and iris collimators. The resulting correction factors differ from unity by up to +11% for air-filled microchambers and -6% for diodes at the smallest field size (5 mm), and tend towards unity with increasing field size (correction factor magnitude <1% for all detectors at field sizes >15 mm). Output factor measurements performed using these detectors with fixed and iris collimators on two different CyberKnife systems showed initial differences between detectors of >15% at 5 mm field size. After correction the measurements on each unit agreed within ?1.5% at the smallest field size. This paper provides a complete set of correction factors needed to apply a new small field dosimetry formalism to both collimator types on the CyberKnife system using a range of commonly used detectors. PMID:22617842

Francescon, P; Kilby, W; Satariano, N; Cora, S

2012-06-21

145

Monte Carlo simulated correction factors for machine specific reference field dose calibration and output factor measurement using fixed and iris collimators on the CyberKnife system  

NASA Astrophysics Data System (ADS)

Monte Carlo (MC) simulation of dose to water and dose to detector has been used to calculate the correction factors needed for dose calibration and output factor measurements on the CyberKnife system. Reference field ionization chambers simulated were the PTW 30006, Exradin A12, and NE 2571 Farmer chambers, and small volume chambers PTW 31014 and 31010. Correction factors for Farmer chambers were found to be 0.7%-0.9% larger than those determined from TRS-398 due mainly to the dose gradient across the chamber cavity. For one microchamber where comparison was possible, the factor was 0.5% lower than TRS-398 which is consistent with previous MC simulations of flattening filter free Linacs. Output factor detectors simulated were diode models PTW 60008, 60012, 60017, 60018, Sun Nuclear edge detector, air-filled microchambers Exradin A16 and PTW 31014, and liquid-filled microchamber PTW 31018 microLion. Factors were generated for both fixed and iris collimators. The resulting correction factors differ from unity by up to +11% for air-filled microchambers and -6% for diodes at the smallest field size (5 mm), and tend towards unity with increasing field size (correction factor magnitude <1% for all detectors at field sizes >15 mm). Output factor measurements performed using these detectors with fixed and iris collimators on two different CyberKnife systems showed initial differences between detectors of >15% at 5 mm field size. After correction the measurements on each unit agreed within ˜1.5% at the smallest field size. This paper provides a complete set of correction factors needed to apply a new small field dosimetry formalism to both collimator types on the CyberKnife system using a range of commonly used detectors.

Francescon, P.; Kilby, W.; Satariano, N.; Cora, S.

2012-06-01

146

Image quality improvements of electronic portal imaging devices by multi-level gain calibration and temperature correction.  

PubMed

Amorphous silicon (aSi:H) flat panel detectors are prevalent in radiotherapy for megavoltage imaging tasks. Any clinical and dosimetrical application requires a well-defined dose response of the system to achieve meaningful results. Due to radiation damages, panels deteriorate and the linearity of pixel response to dose as well as the stability with regard to changing operating temperatures get worse with time. Using a single level gain correction can lead to an error of about 23% when irradiating a flood field image with 100 MU min(-1) on an old detector. A multi-level gain (MLG) correction is introduced, emending the nonlinearities and subpanel-related artifacts caused by insufficient radiation hardness of amplifiers in the read-out electronics. With rising temperature, offset values typically increase (up to 300 gray values) while the response at higher dose values per frame remain constant for a majority of pixels. To account for temperature-related image artifacts, two additional temperature correction methods have been developed. MLG in combination with temperature corrections can re-establish the aSi:H image quality to the performance required by reliable medical verification tools. Furthermore, the life span and recalibration intervals of these costly devices can be prolonged decisively. PMID:23999060

Huber, S; Mooslechner, M; Mitterlechner, B; Weichenberger, H; Serpa, M; Sedlmayer, F; Deutschmann, H

2013-09-21

147

Image quality improvements of electronic portal imaging devices by multi-level gain calibration and temperature correction  

NASA Astrophysics Data System (ADS)

Amorphous silicon (aSi:H) flat panel detectors are prevalent in radiotherapy for megavoltage imaging tasks. Any clinical and dosimetrical application requires a well-defined dose response of the system to achieve meaningful results. Due to radiation damages, panels deteriorate and the linearity of pixel response to dose as well as the stability with regard to changing operating temperatures get worse with time. Using a single level gain correction can lead to an error of about 23% when irradiating a flood field image with 100 MU min-1 on an old detector. A multi-level gain (MLG) correction is introduced, emending the nonlinearities and subpanel-related artifacts caused by insufficient radiation hardness of amplifiers in the read-out electronics. With rising temperature, offset values typically increase (up to 300 gray values) while the response at higher dose values per frame remain constant for a majority of pixels. To account for temperature-related image artifacts, two additional temperature correction methods have been developed. MLG in combination with temperature corrections can re-establish the aSi:H image quality to the performance required by reliable medical verification tools. Furthermore, the life span and recalibration intervals of these costly devices can be prolonged decisively.

Huber, S.; Mooslechner, M.; Mitterlechner, B.; Weichenberger, H.; Serpa, M.; Sedlmayer, F.; Deutschmann, H.

2013-09-01

148

Optimize placement of in-plant power-factor correction capacitors  

SciTech Connect

One large capacity bank, placed on the industrial power user`s main bus, corrects the metered power factor, but it provides little additional benefit for the power system inside the plant. If instead, capacitors are placed closer to motor loads, a large portion of the reactive power is supplied locally rather than from the utility source. This cuts losses in feeders and step-down transformers within the plant. In addition, capacitors can be released from serving non-motor loads while providing better regulation on longer, heavily loaded circuits. Bonneville Power Administration (BPA) recently developed a guidebook and software to help its industrial customers in the Pacific Northwest to improve power factor in their plants and save money on their electric bills. The guidebook and software take the user through an easy-to-use, step-by-step process that includes worksheets at key points. The tools make the process much simpler for industrial power users, whose primary expertise is usually not on electrical systems. Either the guidebook or the software program-written for Microsoft Windows 3.1 - allow the user to determine the amount of capacitors required, where to place them to minimize losses, the economic payback, and how to avoid some of the common pitfalls that adversely affect power quality and the viability of industrial equipment.

Kennedy, B. [Bonneville Power Administration, Portland, OR (United States)

1995-10-01

149

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Temperature derating factor (T) for steel pipe. 192.115 Section...192.115 Temperature derating factor (T ) for steel pipe. The temperature derating...Celsius) Temperaturederating factor (T) 250 °F (121 °C) or less...

2013-10-01

150

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Temperature derating factor (T) for steel pipe. 192.115 Section...192.115 Temperature derating factor (T ) for steel pipe. The temperature derating...Celsius) Temperaturederating factor (T) 250 °F (121 °C) or less...

2012-10-01

151

Real-time prediction of seismic ground motion (II): real-time correction of frequency-dependent site amplification factors  

NASA Astrophysics Data System (ADS)

In Part I, real-time estimation of wavefield using data assimilation and time evolutional prediction using Kirchhoff integral are discussed. For actual application of them in Earthquake Early Warning (EEW), site amplification factor should be corrected in real time. Site amplification is an important factor in addition to source and propagation factors which control the amplitude of seismic waves. The site factor has frequency dependence, and the amplification of high frequency waves is usually different from that of low frequency waves. In many EEW systems, the site amplification factor has been considered as scalar value ignoring the frequency dependence, in which amplification of PGA (or PGV) or increment of seismic intensity is used. The frequency-dependent site amplification factor has not yet fully taken into account. Data assimilation and Kirchhoff integral are powerful techniques for time evolutional prediction. For the application in EEW, frequency-dependent site amplification factors should be corrected in real time (inverse filtering) at observation points, and then should be applied in real time (simulation filtering) for evaluation of ground motion at a target point. A method is proposed in which the frequency dependent site factor can be corrected in real time. The frequency-dependent site factor is modeled by the linear system of the first and second order low-pass and high-pass filters. A causal recursive IIR filter in time domain is estimated from the linear system using bilinear transform and pre-warping methods of digital filtering technique. Using the causal filter, the site amplification factor is corrected in real time even when the site factor has strong frequency dependence. The causal filter enables us to predict the waveforms at target point when the seismic wave start to be observed at the observation point, if the site amplification factor of the target point relative to that of the observation point is known. Instead of rapid estimation of hypocentral location and magnitude, time evolutional prediction is a powerful method for real-time prediction of ground motion for EEW, which is applicable even for cases of strong rupture directivity and large source extent. Techniques of data assimilation and real time correction of site amplification factors will be applied for the time evolutional prediction. An example of the real time correction of the frequency-dependent site factors is presented using data from borehole seismometer (depth: 504m), and also using data of neighboring stations (distance: 28km) in the Kanto region, Japan. Waveforms of the target point are reproduced well from the waveform at the observation point by using the approach of the time evolutional prediction.

Hoshiba, M.

2013-05-01

152

Determination of ²³?Pu airborne concentration alpha correction factor for a zinc sulfide detector via ambient ²²²Rn progeny air sampling.  

PubMed

This research empirically determined the ²³?Pu airborne concentration alpha correction factor for an ADM-300 zinc sulfide detection system via ambient ²²²Rn progeny air sampling using a RADeCO high volume air sampler. Radon progeny air samples were collected on a four inch glass fiber filter and evaluated on both a high purity germanium detector and the ADM?-300 simultaneously using the three count method. These data were analyzed to obtain a loss fraction in the glass fiber filter for the ²¹?Bi collected. The ²¹?Bi response then was used to estimate a loss fraction for ²³?Pu. The ²³?Pu airborne concentration alpha correction factor for the ADM-300 detection system was found to be 445 ± 47 dpm ft³ cpm?¹ m?³ as compared to a previously published correction factor of 500 dpm ft³ cpm?¹ m?³. PMID:21399436

Hale, Alan C; Tries, Mark A

2011-02-01

153

Irradiated, colour-temperature-corrected accretion discs in ultraluminous X-ray sources  

NASA Astrophysics Data System (ADS)

Although attempts have been made to constrain the stellar types of optical counterparts to ultraluminous X-ray sources (ULXs), the detection of optical variability instead suggests that they may be dominated by reprocessed emission from X-rays which irradiate the outer accretion disc. Here, we report results from a combined X-ray and optical spectral study of a sample of ULXs, which were selected for having broadened disc-like X-ray spectra and known optical counterparts. We simultaneously fit optical and X-ray data from ULXs with a new spectral model of emission from an irradiated, colour-temperature-corrected accretion disc around a black hole, with a central Comptonizing corona. We find that the ULXs require reprocessing fractions of ˜10-3, which is similar to sub-Eddington thermal dominant state black hole binaries (BHBs), but less than has been reported for ULXs with soft ultraluminous X-ray spectra. We suggest that the reprocessing fraction may be due to the opposing effects of self-shielding in a geometrically thick supercritical accretion disc and reflection from far above the central black hole by optically thin material ejected in a natal super-Eddington wind. Then, the higher reprocessing fractions reported for ULXs with wind-dominated X-ray spectra may be due to enhanced scattering on to the outer disc via the stronger wind in these objects. Alternatively, the accretion discs in these ULXs may not be particularly geometrically thick, rather they may be similar in this regard to the thermal dominant state BHBs.

Sutton, Andrew D.; Done, Chris; Roberts, Timothy P.

2014-11-01

154

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

SciTech Connect

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 ? Cha cluster, the TW Hydra Association, the ? 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

Pecaut, Mark J.; Mamajek, Eric E. [University of Rochester, Department of Physics and Astronomy, Rochester, NY 14627-0171 (United States)

2013-09-01

155

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

NASA Astrophysics Data System (ADS)

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 ? Cha cluster, the TW Hydra Association, the ? 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

Pecaut, Mark J.; Mamajek, Eric E.

2013-09-01

156

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

NASA Astrophysics Data System (ADS)

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 correction factor is almost solely influenced by non-elastic nuclear interactions the results are also relevant for plastic phantoms that consist of carbon, oxygen and hydrogen atoms as well as for soft tissues.

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

2013-05-01

157

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

PubMed

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 correction factor is almost solely influenced by non-elastic nuclear interactions the results are also relevant for plastic phantoms that consist of carbon, oxygen and hydrogen atoms as well as for soft tissues. PMID:23629423

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

2013-05-21

158

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

159

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

160

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

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

161

Temperature can interact with landscape factors to affect songbird productivity.  

PubMed

Increased temperatures and more extreme weather patterns associated with global climate change can interact with other factors that regulate animal populations, but many climate change studies do not incorporate other threats to wildlife in their analyses. We used 20 years of nest-monitoring data from study sites across a gradient of habitat fragmentation in Missouri, USA, to investigate the relative influence of weather variables (temperature and precipitation) and landscape factors (forest cover and edge density) on the number of young produced per nest attempt (i.e., productivity) for three species of songbirds. We detected a strong forest cover × temperature interaction for the Acadian Flycatcher (Empidonax virescens) on productivity. Greater forest cover resulted in greater productivity because of reduced brood parasitism and increased nest survival, whereas greater temperatures reduced productivity in highly forested landscapes because of increased nest predation but had no effect in less forested landscapes. The Indigo Bunting (Passerina cyanea) exhibited a similar pattern, albeit with a marginal forest cover × temperature interaction. By contrast, productivity of the Northern Cardinal (Cardinalis cardinalis) was not influenced by landscape effects or temperature. Our results highlight a potential difficulty of managing wildlife in response to global change such as habitat fragmentation and climate warming, as the habitat associated with the greatest productivity for flycatchers was also that most negatively influenced by high temperatures. The influence of high temperatures on nest predation (and therefore, nest predators) underscores the need to acknowledge the potential complexity of species' responses to climate change by incorporating a more thorough consideration of community ecology in the development of models of climate impacts on wildlife. PMID:23504884

Cox, W Andrew; Thompson, Frank R; Reidy, Jennifer L; Faaborg, John

2013-04-01

162

The refractometer index as a correction factor for urinary estradiol in rhesus females.  

PubMed

Refractometer indexes were standardized and found to be highly correlated (r = 0.831) to actual creatinine levels. Urinary estradiol corrected by creatinine levels and refractometer indexes were found to be highly correlated (r = 0.857). Predicted ovulation was the same day in 86% of the ovulatory cycles predicted by creatinine and refractometer corrected estradiol levels. Refractometer indexes may be used in place of creatinine levels to correct for urine concentration fluctuations when predicting ovulation in the rhesus female. PMID:2213858

Thibodeaux, J K; Anzalone, C A; Voelkel, S A; Roussel, J D; Goodeaux, L L

1990-01-01

163

A two-thermocouples probe for radiation corrections of measured temperatures in compartment fires  

Microsoft Academic Search

Bare-bead thermocouples are widely used for measuring temperature fields in compartment fires. It is well-known that temperature readings using such a device can be significantly affected by radiation errors, the apparent thermocouple junction temperature being thus different from the true gas temperature. However, a probe consisting of two thermocouples of unequal diameters, but made of the same material can be

S Brohez; C Delvosalle; G Marlair

2004-01-01

164

Factors that hinder offender reentry success: a view from community corrections officers.  

PubMed

Within the institutional correctional literature, much has been written about the differences in authority between correctional officers and inmates. Recently, researchers have begun exploring the differences in authority between ex-offenders and community corrections officers (CCOs). Emerging literature in the correctional field suggests that ex-offenders perceive CCOs as being socially distant from them and have doubt as to whether CCOs are genuine in their attempts to assist the ex-offenders in reintegrating back into the community. Using qualitative data from a sample of 132 federal and state corrections officers in Seattle, Washington, this investigation advances previous research by examining officers' perceptions of social distance with their clients. Results from the survey responses and policy implications are presented. PMID:20228319

Gunnison, Elaine; Helfgott, Jacqueline B

2011-04-01

165

Correction factors for saturation effects in white light and laser absorption spectroscopy for application to low pressure plasmas  

SciTech Connect

In white light absorption spectroscopy, the broadening of the absorption signal due to the apparatus profile of the spectrometer may lead to an underestimation of the determined density as one measures an apparent optical depth. This is in particular true for high optical depth where saturation effects of the transmitted intensity occur. Provided that the line profile of the absorption line is known, the apparent optical depth effect can be accounted for by introducing a correction factor. The impact of the saturation and the approach of considering the effect are demonstrated for argon and indium lines in low pressure plasmas where correction factors of one order of magnitude or even higher are reached very easily. For the indium line, the hyperfine splitting has been taken into account. In laser absorption, the line profile is resolved. However, the weak but rather broad background emission of the laser diode can cause a saturation signal at the photo diode resulting also in an underestimation of the density obtained from the analysis. It is shown that this can be taken into account by fitting the theoretical line profile to the measured absorption signal which yields also a correction factor. The method is introduced and demonstrated at the example of the cesium resonance line including the hyperfine splitting. Typical correction factors around two are obtained for the cesium ground state density at conditions of a low pressure negative hydrogen ion source in which cesium is evaporated to enhance the negative ion production.

Briefi, S. [Lehrstuhl fuer Experimentelle Plasmaphysik, Universitaet Augsburg, Universitaetsstr. 1, 86135 Augsburg (Germany); Wimmer, C.; Fantz, U. [Lehrstuhl fuer Experimentelle Plasmaphysik, Universitaet Augsburg, Universitaetsstr. 1, 86135 Augsburg (Germany); Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

2012-05-15

166

Capture of instantaneous temperature in oscillating flows: use of constant-voltage anemometry to correct the thermal lag of cold wires operated by constant-current anemometry.  

PubMed

A new procedure for the instantaneous correction of the thermal inertia of cold wires operated by a constant-current anemometer is proposed for oscillating flows. The thermal inertia of cold wires depends both on the wire properties and on the instantaneous incident flow velocity. Its correction is challenging in oscillating flows because no relationship between flow velocity and heat transfer around the wire is available near flow reversal. The present correction procedure requires neither calibration data for velocity nor thermophysical or geometrical properties of the wires. The method relies on the splitting of the time lag of cold wires into two factors, which are obtained using a constant-voltage anemometer in the heated mode. The first factor, which is intrinsic to the wire, is deduced from time-constant measurements performed in a low-turbulence flow. The second factor, which depends on the instantaneous flow velocity, is acquired in situ. In oscillating flows, data acquisition can be synchronized with a reference signal so that the same wire is alternatively operated in the cold mode by a constant-current anemometer and in the heated mode by a constant-voltage anemometer. Validation experiments are conducted in an acoustic standing-wave resonator, for which the fluctuating temperature field along the resonator axis is known independently from acoustic pressure measurements, so that comparisons can be made with cold-wire measurements. It is shown that despite the fact that the wire experiences flow reversal, the new procedure recovers accurately the instantaneous temperature of the flow. PMID:20113124

Berson, Arganthaël; Poignand, Gaëlle; Blanc-Benon, Philippe; Comte-Bellot, Geneviève

2010-01-01

167

Temperature dependent thermoelectric material power factor measurement system  

NASA Astrophysics Data System (ADS)

Thermoelectric materials can be used for cooling/heating applications, or converting waste heat into electricity. Novel thermoelectric materials have been discovered in recent years. Characterization of an electrical conductivity and thermopower of a sample from room temperature to ?900 K is often necessary for thermoelectric materials. This paper describes a system built for measurement of the power factor of thermoelectric materials from 300 to 1273 K. Characterization results of the system are also presented.

D'Angelo, Jonathan; Downey, Adam; Hogan, Timothy

2010-07-01

168

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

SciTech Connect

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 correction factors associated with the proposed intermediate calibration fields and the clinical fields under investigation show that depending on the clinical field and the detector used, either a machine-specific reference field or a plan-class specific reference field is more representative for the clinical field. Given the experimental and numerical uncertainties and the small number of clinical fields considered in this study the significance of these observations is limited and it remains unclear for the CyberKnife if there would be a significant gain in using a pcsr field rather than a msr field as reference field for relative dosimetry.

Gago-Arias, Araceli; Antolin, Elena; Fayos-Ferrer, Francisco; Simon, Rocio; Gonzalez-Castano, Diego M.; Palmans, Hugo; Sharpe, Peter; Gomez, Faustino; Pardo-Montero, Juan [Departamento de Fisica de Particulas, Facultad de Fisica, Universidade de Santiago de Compostela, A Coruna 15782 (Spain); Servicio de Fisica Medica, Hospital Ruber Internacional, Madrid 28034 (Spain); Departamento de Fisica de Particulas, Facultad de Fisica, Universidade de Santiago de Compostela, A Coruna 15782, Spain and Laboratorio de Radiofisica, Universidade de Santiago de Compostela, Santiago de Compostela, A Coruna 15782 (Spain); National Physical Laboratory, Teddington, Middx TW11 OLW (United Kingdom); Departamento de Fisica de Particulas, Facultad de Fisica, Universidade de Santiago de Compostela, A Coruna 15782, Spain and Laboratorio de Radiofisica, Universidade de Santiago de Compostela, Santiago de Compostela, A Coruna 15782 (Spain); Departamento de Fisica de Particulas, Facultad de Fisica, Universidade de Santiago de Compostela, A Coruna 15782 (Spain)

2013-01-15

169

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

NASA Technical Reports Server (NTRS)

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).

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

2003-01-01

170

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

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

171

Early Cenozoic benthic foraminiferal isotopes: Species reliability and interspecies correction factors  

E-print Network

Early Cenozoic benthic foraminiferal isotopes: Species reliability and interspecies correction Cenozoic benthic foraminifera commonly used for isotopic measurements (Cibicidoides spp., Nuttallides isotopic offsets appear to have changed through the Cenozoic, either (1) as a result of evolutionary

Royer, Dana

172

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

PubMed

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. PMID:24085086

Cao, Yanpeng; Tisse, Christel-Loic

2013-09-01

173

Reference dosimetry condition and beam quality correction factor for CyberKnife beam.  

PubMed

This article is intended to improve the certainty of the absorbed dose determination for reference dosimetry in CyberKnife beams. The CyberKnife beams do not satisfy some conditions of the standard reference dosimetry protocols because of its unique treatment head structure and beam collimating system. Under the present state of affairs, the reference dosimetry has not been performed under uniform conditions and the beam quality correction factor kQ for an ordinary 6 MV linear accelerator has been temporally substituted for the kQ of the CyberKnife in many sites. Therefore, the reference conditions and kQ as a function of the beam quality index in a new way are required. The dose flatness and the error of dosimeter reading caused by radiation fields and detector size were analyzed to determine the reference conditions. Owing to the absence of beam flattening filter, the dose flatness of the CyberKnife beam was inferior to that of an ordinary 6 MV linear accelerator. And if the absorbed dose is measured with an ionization chamber which has cavity length of 2.4, 1.0 and 0.7 cm in reference dosimetry, the dose at the beam axis for a field of 6.0 cm collimator was underestimated 1.5%, 0.4%, and 0.2% on a calculation. Therefore, the maximum field shaped with a 6.0 cm collimator and ionization chamber which has a cavity length of 1.0 cm or shorter were recommended as the conditions of reference dosimetry. Furthermore, to determine the kQ for the CyberKnife, the realistic energy spectrum of photons and electrons in water was simulated with the BEAMnrc. The absence of beam flattening filter also caused softer photon energy spectrum than that of an ordinary 6 MV linear accelerator. Consequently, the kQ for ionization chambers of a suitable size were determined and tabulated as a function of measurable beam quality indexes in the CyberKnife beam. PMID:18975705

Kawachi, Toru; Saitoh, Hidetoshi; Inoue, Mitsuhiro; Katayose, Tetsurou; Myojoyama, Atsushi; Hatano, Kazuo

2008-10-01

174

Voluntary STD testing and treatment program at a metropolitan correctional facility: evaluation of test acceptability and associated risk factors.  

PubMed

Few studies have addressed challenges of diagnosis and treatment of sexually transmitted diseases (STDs) within correctional facilities. Initiatives that screen all inmates can be cost-prohibitive, while symptom-based screening undoubtedly fails to recognize significant numbers of asymptomatically infected persons. This study discusses a voluntary STD screening and treatment program developed at the Douglas County (Nebraska) Department of Corrections where student volunteers interviewed, screened, and educated 456 inmates. Inmate urine samples and interview responses about risk behaviors and motivators for participation in the screening program were analyzed. The results support the ongoing project method to screen and treat inmates in the community correctional facility. Risk factor analysis suggests that targeted testing and treatment efforts may have a role in providing cost-effective care for STD among the incarcerated population. PMID:24352406

Brown, Christopher K; Earley, Mary; Shaikh, Raees; Fickenscher, Jillian; Ott, Jessica; Person, Austin; Islam, K M Monirul; Simonsen, Kari; Sandkovsky, Uriel; Kaiser, Katherine Laux; Foxall, Mark; Margalit, Ruth

2014-01-01

175

Physical factors in cataractogenesis: ambient ultraviolet radiation and temperature.  

PubMed

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. PMID:3700027

Sliney, D H

1986-05-01

176

Physical factors in cataractogenesis: ambient ultraviolet radiation and temperature  

SciTech Connect

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.

Sliney, D.H.

1986-05-01

177

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

PubMed

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. PMID:23848803

Seta, Takeshi

2013-06-01

178

Separating temperature from other factors in phenological measurements  

NASA Astrophysics Data System (ADS)

Phenological observations offer a simple and effective way to measure climate change effects on the biosphere. While some species in northern mixed forests show a highly sensitive site preference to microenvironmental differences (i.e., the species is present in certain areas and absent in others), others with a more plastic environmental response (e.g., Acer saccharum, sugar maple) allow provisional separation of the universal "background" phenological variation caused by in situ (possibly biological/genetic) variation from the microclimatic gradients in air temperature. Moran's I tests for spatial autocorrelation among the phenological data showed significant ( ? ? 0.05) clustering across the study area, but random patterns within the microclimates themselves, with isolated exceptions. In other words, the presence of microclimates throughout the study area generally results in spatial autocorrelation because they impact the overall phenological development of sugar maple trees. However, within each microclimate (where temperature conditions are relatively uniform) there is little or no spatial autocorrelation because phenological differences are due largely to randomly distributed in situ factors. The phenological responses from 2008 and 2009 for two sugar maple phenological stages showed the relationship between air temperature degree-hour departure and phenological change ranged from 0.5 to 1.2 days earlier for each additional 100 degree-hours. Further, the standard deviations of phenological event dates within individual microclimates (for specific events and years) ranged from 2.6 to 3.8 days. Thus, that range of days is inferred to be the "background" phenological variation caused by factors other than air temperature variations, such as genetic differences between individuals.

Schwartz, Mark D.; Hanes, Jonathan M.; Liang, Liang

2014-09-01

179

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

PubMed Central

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

Gelman, David; Schwartz, Steven D.

2011-01-01

180

Emissivity correcting pyrometer for temperature measurement in low pressure chemical vapor deposition  

Microsoft Academic Search

Rapid thermal processing (RTP) low pressure chemical vapor deposition (LPCVD) requires accurate wafer temperature measurement to control film deposition during processing. The temperature sensor discussed detects a portion of the target radiance as a DC signal. The remainder of the target radiance is chopped, reflected back onto the target, and recollected by the sensor as an AC signal. Two versions

M. J. Fordham; R. F. Gansman; F. Y. Sorrell

1993-01-01

181

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

PubMed

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 mm(3) 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 cm(3) 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. PMID:22505592

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

2012-05-01

182

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

NASA Astrophysics Data System (ADS)

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.

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

2012-05-01

183

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

DOEpatents

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.

Horn, Kevin M.

2013-07-09

184

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

PubMed

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. PMID:24487887

Cao, Yanpeng; Tisse, Christel-Loic

2014-02-01

185

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Temperature derating factor (T) for steel pipe. 192.115 Section...192.115 Temperature derating factor (T ) for steel pipe. The temperature derating...Celsius) Temperature derating factor (T) 250 °F (121 °C) or less...

2010-10-01

186

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Temperature derating factor (T) for steel pipe. 192.115 Section...192.115 Temperature derating factor (T ) for steel pipe. The temperature derating...Celsius) Temperature derating factor (T) 250 °F (121 °C) or less...

2011-10-01

187

Novel molecules for the correction of factor Xa generation and phenotype in hemophilia.  

PubMed

In the intact hemostatic system, the amount of factor Xa needed for efficient blood coagulation is supplied by the complex between factors VIIIa and IXa. Because hemophilia A patients lack factor VIII and hemophilia B patients lack factor IX, they share a bleeding phenotype that has its root in a dramatically decreased ability to generate factor Xa. These patients are currently treated by replacement therapy with factor VIII and IX, respectively, or, in case they have developed neutralizing inhibitory antibodies against the replacing factor, with a bypassing agent such as factor VIIa (NovoSeven®) or FEIBA®. This review briefly describes a number of novel promising approaches currently in the discovery or clinical development phase aiming at increased factor Xa generation in hemophilia. PMID:22405049

Persson, Egon

2012-05-01

188

Universal input single-phase single-stage power supply with power factor correction and automatic voltage clamping  

Microsoft Academic Search

A single-phase single-stage power supply with power factor correction and automatic voltage clamping is proposed in this paper. This topology combines a boost input current shaper with a new double winding clamped DC\\/DC power converter. With this configuration, when the main switch is turned off, the voltage of the switch is automatically clamped to the sum of the two bulk

Chongming Qiao; Keyue M. Smedley

2001-01-01

189

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

SciTech Connect

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.

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

1993-05-01

190

Sustained phenotypic correction of hemophilia B dogs with a factor IX null mutation by liver-directed gene therapy  

Microsoft Academic Search

Hemophilia B is an X-linked coagulopathy caused by absence of functional coagula- tion factor IX (FIX). Using adeno-associ- ated virus (AAV)-mediated, liver-directed gene therapy, we achieved long-term (> 17 months) substantial correction of canine hemophilia B in 3 of 4 animals, including 2 dogs with an FIX null mutation. This was accomplished with a comparatively low dose of 1 3

Jane D. Mount; Roland W. Herzog; D. Michael Tillson; Susan A. Goodman; Nancy Robinson; Mark L. McCleland; Dwight Bellinger; Timothy C. Nichols; Valder R. Arruda; Clinton D. Lothrop Jr; Katherine A. High

2002-01-01

191

Correction factors for the determination of oxygen in silicon by IR spectrometry  

Microsoft Academic Search

In order to achieve a high multilaboratory precision in measuring the oxygen content in CZ silicon slices and wafers by means of IR absorption spectroscopy various deviations from ideal measurement conditions are discussed and correction methods are presented. The main sources for measurement errors exceeding {plus minus} 1% standard deviation are: the radiation scattering at rough wafer reverse sides, the

F. Schomann; K. Graff

1989-01-01

192

Nucleon form factors and final state radiative corrections to $e^+e^-\\to \\bar p p ?$  

E-print Network

New parametrisation for the electric and the magnetic form factors of proton and neutron are presented. The proton form factors describe well the recent measurements by BaBar collaboration and earlier ones of the ratio of the form factors in space-like region. The neutron form factors are consistent with earlier measurements of neutron pair production and ratio of the form factors in the space-like region. These form factors are implemented into the generator PHOKHARA, which simulates the reactions $e^+e^-\\to \\bar p p \\gamma$ and $e^+e^-\\to \\bar n n\\gamma$. The influence of final state radiation is investigated.

Henryk Czyz; Johann H. Kuhn; Szymon Tracz

2014-07-30

193

Estimation of the flow profile correction factor of a transit-time ultrasonic flow meter for the feedwater flow measurement in a nuclear power plant  

Microsoft Academic Search

A new method to estimate the flow profile correction factor (FPCF) for a transit-time ultrasonic flow meter (UFM) having a diametral transducer configuration is introduced in this work. For the adaptation of a diametral UFM for a feedwater measurement, the optimized flow profile correction factor is obtained through experiments and a simulation in actual flow conditions. The log function curve

Jae Cheon Jung; Poong Hyun Seong

2005-01-01

194

Sky view factor analysis implications for urban air temperature differences  

NASA Astrophysics Data System (ADS)

This study identifies the use of the sky view factor (SVF) in urban climate studies. In addition, it relates air temperature differences to the SVF and examines these differences with respect to the height at which fish-eye photographs are taken for the calculation of the SVF. The study focuses on night-time air temperature patterns within the urban canopy using data collected during clear, calm nights from sixteen permanent stations and from car measurements. Fish-eye photographs taken at two levels (2 m above ground and at ground level) are compared and shown to be statistically different. The results of the study performed in Göteborg, Sweden, indicate a fairly strong relationship between air temperature and SVF. The permanent stations used indicate that it is better to use fish-eye photographs taken at ground level. The relationship is determined by means of regression analysis. The SVF variation in urban areas and the importance of SVF in relation to other central parameters such as thermal admittance are also discussed.

Svensson, Marie K.

2004-09-01

195

Evaluation of the screened QED corrections to the g factor and the hyperfine splitting of lithiumlike ions  

SciTech Connect

The screened QED corrections of first order in {alpha} and 1/Z to the g factor and the hyperfine splitting of lithiumlike ions are evaluated within ab initio quantum-electrodynamical approach. The complete gauge-invariant set of the two-electron self-energy diagrams in the presence of the magnetic field and a dominant part of the two-electron vacuum-polarization diagrams are calculated. The most accurate values of the g factor of Li-like lead and uranium are presented. The theoretical prediction for the specific difference of the hyperfine splittings of H- and Li-like bismuth is improved.

Glazov, D. A.; Volotka, A. V. [Department of Physics, St. Petersburg State University, Oulianovskaya 1, Petrodvorets, St. Petersburg 198504 (Russian Federation); Institut fuer Theoretische Physik, Technische Universitaet Dresden, Mommsenstrasse 13, D-01062 Dresden (Germany); Shabaev, V. M.; Tupitsyn, I. I. [Department of Physics, St. Petersburg State University, Oulianovskaya 1, Petrodvorets, St. Petersburg 198504 (Russian Federation); Plunien, G. [Institut fuer Theoretische Physik, Technische Universitaet Dresden, Mommsenstrasse 13, D-01062 Dresden (Germany)

2010-06-15

196

Evaluation of the screened QED corrections to the g factor and the hyperfine splitting of lithiumlike ions  

NASA Astrophysics Data System (ADS)

The screened QED corrections of first order in ? and 1/Z to the g factor and the hyperfine splitting of lithiumlike ions are evaluated within ab initio quantum-electrodynamical approach. The complete gauge-invariant set of the two-electron self-energy diagrams in the presence of the magnetic field and a dominant part of the two-electron vacuum-polarization diagrams are calculated. The most accurate values of the g factor of Li-like lead and uranium are presented. The theoretical prediction for the specific difference of the hyperfine splittings of H- and Li-like bismuth is improved.

Glazov, D. A.; Volotka, A. V.; Shabaev, V. M.; Tupitsyn, I. I.; Plunien, G.

2010-06-01

197

Correction factors applied to finger dosimetry: a theoretical assessment of appropriate values for use in handling radiopharmaceuticals.  

PubMed

United States Nuclear Regulatory Commission (USNRC) regulations limit the dose to the skin to 500 mSv per year. This is also the dose limit recommended by the International Commission on Radiological Protection (ICRP). The operational quantity recommended by ICRP for quantifying dose to the skin is the personal dose equivalent, Hp(0.07) and is identical to NRC's shallow dose equivalent, Hs, also measured at a skin depth of 7 mg cm-2. However, whereas ICRP recommends averaging the dose to the skin over an area of 1 cm regardless of the size of the exposed area of skin, USNRC requires the shallow dose equivalent to be averaged over 10 cm. To monitor dose to the skin of the hands of workers handling radioactive materials and particularly in radiopharmaceutical manufacturing facilities, which is the focus of this work, workers are frequently required to wear finger ring dosimeters. The dosimeters monitor the dose at the location of the sensitive element, but this is not the dose required to show compliance (i.e., the dose averaged over the highest exposed contiguous 10 cm of skin). Therefore, it may be necessary to apply a correction factor that enables estimation of the required skin dose from the dosimeter reading. This work explored the effects of finger ring placement and of the geometry of the radioactive materials being handled by the worker on the relationship between the dosimeter reading and the desired average dose. A mathematical model of the hand was developed for this purpose that is capable of positioning the fingers in any desired grasping configuration, thereby realistically modeling manipulation of any object. The model was then used with the radiation transport code MCNP to calculate the dose distribution on the skin of the hand when handling a variety of radioactive vials and syringes, as well as the dose to the dosimeter element. Correction factors were calculated using the results of these calculations and examined for any patterns that may be useful in establishing an appropriate correction factor for this type of work. It was determined that a correction factor of one applied to the dosimeter reading, with the dosimeter placed at the base of the middle finger, provides an adequate estimate of the required average dose during a monitoring period for most commonly encountered geometries. Different correction factors may be required for exceptional or unusual source geometries and must be considered on a case-by-case basis. PMID:21617388

Sherbini, Sami; Ilas, Dan; Eckerman, Keith; DeCicco, Joseph

2011-07-01

198

Correction Factors Applied to Finger Dosimetry: A Theoretical Assessment of Appropriate Values for Use in Handling Radiopharmaceuticals  

SciTech Connect

United States Nuclear Regulatory Commission (USNRC) regulations limit the dose to the skin to 500 mSv per year. This is also the dose limit recommended by the International Commission on Radiological Protection (ICRP). The operational quantity recommended by ICRP for quantifying dose to the skin is the personal dose equivalent, Hp(0.07) and is identical to NRC s shallow dose equivalent, Hs, also measured at a skin depth of 7 mg cm 2. However, whereas ICRP recommends averaging the dose to the skin over an area of 1 cm2 regardless of the size of the exposed area of skin, USNRC requires the shallow dose equivalent to be averaged over 10 cm2. To monitor dose to the skin of the hands of workers handling radioactive materials and particularly in radiopharmaceutical manufacturing facilities, which is the focus of this work, workers are frequently required to wear finger ring dosimeters. The dosimeters monitor the dose at the location of the sensitive element, but this is not the dose required to show compliance (i.e., the dose averaged over the highest exposed contiguous 10 cm2 of skin). Therefore, it may be necessary to apply a correction factor that enables estimation of the required skin dose from the dosimeter reading. This work explored the effects of finger ring placement and of the geometry of the radioactive materials being handled by the worker on the relationship between the dosimeter reading and the desired average dose. A mathematical model of the hand was developed for this purpose that is capable of positioning the fingers in any desired grasping configuration, thereby realistically modeling manipulation of any object. The model was then used with the radiation transport code MCNP to calculate the dose distribution on the skin of the hand when handling a variety of radioactive vials and syringes, as well as the dose to the dosimeter element. Correction factors were calculated using the results of these calculations and examined for any patterns that may be useful in establishing an appropriate correction factor for this type of work. It was determined that a correction factor of one applied to the dosimeter reading, with the dosimeter placed at the base of the middle finger, provides an adequate estimate of the required average dose during a monitoring period for most commonly encountered geometries. Different correction factors may be required for exceptional or unusual source geometries and must be considered on a case-by-case basis.

Sherbini, Sami [NRC; Ilas, Dan [ORNL; Eckerman, Keith F [ORNL; DeCicco, Joseph [NRC

2011-01-01

199

A Hybrid Framework to Bias Correct and Empirically Downscale Daily Temperature and Precipitation from Regional Climate Models  

NASA Astrophysics Data System (ADS)

Bias correction and statistical downscaling are widely used approaches for postprocessing climate simulations generated by global and/or regional climate models. The skills of these approaches are typically assessed in terms of their ability to reproduce historical climate conditions as well as the plausibility and consistency of the derived statistical indicators needed by end users. Current bias correction and downscaling approaches often do not adequately satisfy the two criteria of accurate prediction and unbiased estimation. To overcome this limitation, a hybrid regression framework was developed to both minimize prediction errors and preserve the distributional characteristics of climate observations. Specifically, the framework couples the loss functions of standard (linear or nonlinear) regression methods with a regularization term that penalizes for discrepancies between the predicted and observed distributions. The proposed framework can also be extended to generate physically-consistent outputs across multiple response variables, and to incorporate both reanalysis-driven and GCM-driven RCM outputs into a unified learning framework. The effectiveness of the framework is demonstrated using daily temperature and precipitation simulations from the North American Regional Climate Change Program (NARCCAP) . The accuracy of the framework is comparable to standard regression methods, but, unlike the standard regression methods, the proposed framework is able to preserve many of the distribution properties of the response variables, akin to bias correction approaches such as quantile mapping and bivariate geometric quantile mapping.

Tan, P.; Abraham, Z.; Winkler, J. A.; Perdinan, P.; Zhong, S. S.; Liszewska, M.

2013-12-01

200

Factors affecting characterization of bulk high-temperature superconductors  

SciTech Connect

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.

Hull, J.R. [Argonne National Lab., IL (United States). Energy Technology Div.

1997-11-01

201

Evaluation of split-window and dual-angle correction methods for land surface temperature retrieval from Envisat\\/Advanced Along Track Scanning Radiometer (AATSR) data  

Microsoft Academic Search

Land surface temperature (LST) can be derived from thermal infrared remote sensing data provided that atmospheric and emissivity effects are corrected for. In this paper, two correction methods were evaluated using a database of ground LST measurements and concurrent Envisat\\/Advanced Along Track Scanning Radiometer (AATSR) data. They were the split-window (SW) method, which uses two channels at 11 and 12

César Coll; Vicente Caselles; Joan M. Galve; Enric Valor; Raquel Niclòs; Juan M. Sánchez

2006-01-01

202

Temperature factor for magnetic instability conditions of type - II superconductors  

NASA Astrophysics Data System (ADS)

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-current characteristic. On the whole, the non-isothermal stability conditions expand the existence of allowable stable superconducting states. The non-isothermal approximation permits also to link the theories of the losses, the magnetic instability and the thermal stabilization of superconductors, which are independently developed.

Romanovskii, V.

2014-10-01

203

Review of mathematics, numerical factors, and corrections for dark matter experiments based on elastic nuclear recoil  

Microsoft Academic Search

We present a systematic derivation and discussion of the practical formulae needed to design and interpret direct searches for nuclear recoil events caused by hypothetical weakly interacting dark matter particles. Modifications to the differential energy spectrum arise from the Earth's motion, recoil detection efficiency, instrumental resolution and threshold, multiple target elements, spin-dependent and coherent factors, and nuclear form factor. We

J. D. Lewin; P. F. Smith

1996-01-01

204

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

NASA Astrophysics Data System (ADS)

For low-power low total harmonic distortion (THD), based on the CSMC 0.5 ?m 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 ?A, the stable operating current is 3.85 mA, the power factor is 0.998 and the efficiency is 95.2%.

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

2012-03-01

205

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

206

Geometrical factor correction in grazing incident x-ray fluorescence experiment  

SciTech Connect

The geometrical factor in the grazing incident x-ray fluorescence analysis is an important angle-dependent term, which can have a great effect on the measured data. In this paper, the effects of the geometrical factor on the florescence yield have been demonstrated. A formula is presented to estimate the geometrical factor, which includes the experimental parameters of the beam and setup. The validity of this formula is proven by the good agreement between the calculated fluorescence yields with the experimental results in grazing incident x-ray fluorescence analysis.

Li Wenbin; Zhu Jingtao; Ma Xiaoying; Li Haochuan; Wang Hongchang; Wang Zhanshan [Key Laboratory of Advanced Micro-Structured Materials, MOE, Institute of Precision Optical Engineering, Department of Physics, Tongji University, Shanghai 200092 (China); Sawhney, Kawal J. S. [Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

2012-05-15

207

Coulomb corrections to density and temperature of bosons in heavy ion collisions  

NASA Astrophysics Data System (ADS)

A recently proposed method, based on quadrupole and multiplicity fluctuations in heavy ion collisions, is modified in order to take into account distortions due to the Coulomb field. This is particularly interesting for bosons, such as d and ? particles, produced in heavy ion collisions. We derive the temperatures and densities seen by the bosons and compare them to results of similar calculations for fermions. The resulting energy densities agree rather well with each other and with the one derived from neutron observables. This suggests that a common phenomenon, such as the sudden opening of many reaction channels and/or a liquid-gas phase transition, is responsible for the agreement.

Zheng, Hua; Giuliani, Gianluca; Bonasera, Aldo

2013-08-01

208

Analysis and modeling for fiber-optic gyroscope scale factor based on environment temperature.  

PubMed

To explore and reduce the nonlinear error and temperature dependency of fiber-optic gyroscope (FOG) scale factor, a scale factor modeling method based on temperature is presented in this paper. A hyperbolic curve fitting is proposed according to the characteristic of scale factor under stable temperature at first. Compared to traditional modeling methods, it shows that a higher precision model of scale factor can be obtained. Then the influence of temperature on scale factor is analyzed and then the hyperbolic curve fitting method is extended based on temperature, making it possible to work over the whole potential temperature range of the FOG without degrading the performance. This paper also provides the experimental and verification results. It can be seen that a high precision model of scale factor has been established, the temperature dependency of scale factor has been reduced effectively, and the error due to environment temperature is reduced by one order at least. PMID:22614471

Shen, Chong; Chen, Xiyuan

2012-05-10

209

Partial correction of a severe molecular defect in hemophilia A, because of errors during expression of the factor VIII gene  

SciTech Connect

Although the molecular defect in patients in a Japanese family with mild to moderately severe hemophilia A was a deletion of a single nucleotide T within an A{sub 8}TA{sub 2} sequence of exon 14 of the factor VIII gene, the severity of the clinical phenotype did not correspond to that expected of a frameshift mutation. A small amount of functional factor VIII protein was detected in the patient`s plasma. Analysis of DNA and RNA molecules from normal and affected individuals and in vitro transcription/translation suggested a partial correction of the molecular defect, because of the following: (i) DNA replication/RNA transcription errors resulting in restoration of the reading frame and/or (ii) {open_quotes}ribosomal frameshifting{close_quotes} resulting in the production of normal factor VIII polypeptide and, thus, in a milder than expected hemophilia A. All of these mechanisms probably were promoted by the longer run of adenines, A{sub 10} instead of A{sub 8}TA{sub 2}, after the delT. Errors in the complex steps of gene expression therefore may partially correct a severe frameshift defect and ameliorate an expected severe phenotype. 36 refs., 6 figs.

Young, M.; Antonarakis, S.E. [Univ. of Geneva (Switzerland); Inaba, Hiroshi [Tokyo Medical College (Japan)] [and others

1997-03-01

210

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

NASA Astrophysics Data System (ADS)

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.

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

211

A novel uninterruptible power supply system with active power factor correction  

Microsoft Academic Search

This paper presents a simplified sinusoidal uninterruptible power supply (UPS) system. The proposed scheme includes features such as high power factor, low total harmonic distortion and good dynamic response at the AC output voltage. In addition, the scheme has the desirable characteristics, of high efficiency, simple circuit and low cost compared with a traditional standalone multiple stages UPS with power

Nimrod Vázquez; Carlos Aguilar; Jaime Arau; Ramón O. Cáceres; Ivo Barbi; Jaime Alvarez Gallegos

2002-01-01

212

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

PubMed Central

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, ?0.5mm×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

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

2013-01-01

213

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

NASA Astrophysics Data System (ADS)

Plastic scintillation detectors (PSDs) have many advantages over other detectors in small field dosimetry due to their high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs undergo a quenching effect which makes the signal level reduced significantly when the detector is close to the 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, ?0.5 mm × 4 mm) 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 the 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.

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

2012-12-01

214

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

PubMed

Plastic scintillation detectors (PSDs) have many advantages over other detectors in small field dosimetry due to their high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs undergo a quenching effect which makes the signal level reduced significantly when the detector is close to the 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, ?0.5 mm × 4 mm) 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 the 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

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

2012-12-01

215

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

PubMed Central

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.

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

2014-01-01

216

Correction factors for the determination of bromine with NAA through the activation of {sup 79}Br  

SciTech Connect

The study of environmental aerosol samples often includes analysis of the element bromine. This element is found in most environments and has both anthropogenic and natural sources. Bromine is a trace element in the uncontrolled particulate emissions of oil combustion at utilities, industrial processes with iron and steel, and also a by-product of gypsum production. A major source for bromine in urban areas has been auto emissions. In rural and remote areas, bromine quite often emanates from marine origin. In fact Bottenheim et al. have examined the depletion of ozone during the Arctic sunrise and its correlation to the increase of bromine. Neutron activation analysis (NAA) has been used as an elemental detection method in aerosol and other environmental samples for many elements including bromine. However, Tobler et al. indicated that corrections must be made in calculations of bromine concentrations due to the {sup 79}Br(n, {gamma}){sup 80m}Br {yields} {sup 80}Br reaction. The {sup 80m}Br has a half-life of 4.2 h, while {sup 80}Br has a half-life of 17.7 min. Since for short-lived NAA, the irradiation, decay, and counting times vary, it is desirable to have an equation that will account for the additional {sup 80}Br resulting from {sup 80m}Br. This equation may then be used in any NAA irradiation/decay/counting scheme. The derivation of such an equation, discussion of errors, and validation using experimental results are discussed in this paper.

Biegalski, S.R.; Landsberger, S.

1994-12-31

217

Increased Nerve Growth Factor Signaling in Sensory Neurons of Early Diabetic Rats Is Corrected by Electroacupuncture  

PubMed Central

Diabetic polyneuropathy (DPN), characterized by early hyperalgesia and increased nerve growth factor (NGF), evolves in late irreversible neuropathic symptoms with reduced NGF support to sensory neurons. Electroacupuncture (EA) modulates NGF in the peripheral nervous system, being effective for the treatment of DPN symptoms. We hypothesize that NGF plays an important pathogenic role in DPN development, while EA could be useful in the therapy of DPN by modulating NGF expression/activity. Diabetes was induced in rats by streptozotocin (STZ) injection. One week after STZ, EA was started and continued for three weeks. NGF system and hyperalgesia-related mediators were analyzed in the dorsal root ganglia (DRG) and in their spinal cord and skin innervation territories. Our results show that four weeks long diabetes increased NGF and NGF receptors and deregulated intracellular signaling mediators of DRG neurons hypersensitization; EA in diabetic rats decreased NGF and NGF receptors, normalized c-Jun N-terminal and p38 kinases activation, decreased transient receptor potential vanilloid-1 ion channel, and possibly activated the nuclear factor kappa-light-chain-enhancer of activated B cells (Nf-?B). In conclusion, NGF signaling deregulation might play an important role in the development of DPN. EA represents a supportive tool to control DPN development by modulating NGF signaling in diabetes-targeted neurons. PMID:23710226

Nori, Stefania Lucia; Rocco, Maria Luisa; Florenzano, Fulvio; Ciotti, Maria Teresa; Aloe, Luigi

2013-01-01

218

Temperature dependence of the enhancement factor of cidnp created by the photolysis of benzoyl peroxide  

NASA Astrophysics Data System (ADS)

The enhancement factor of the nuclear polarization created by the photolysis of benzoyl peroxide in CDCl 3 is measured at various temperatures. The experimental enhancement factor agrees with the theoretical value calculated by the theory proposed by Pedersen and Freed. Further, the temperature dependence of the enhancement factor is well interpreted by the continuous diffusion model.

Takahashi, Satoshi; Terazima, Masahide; Azumi, Tohru

1990-03-01

219

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

SciTech Connect

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.

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

2013-01-01

220

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

PubMed Central

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

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

2011-01-01

221

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)

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.

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

222

Temperature factor effect on the structure of the separated flow within a supersonic gas stream  

Microsoft Academic Search

The effect of the temperature factor, that is, the ratio of the body temperature to the freestream stagnation temperature,\\u000a on the structure of the separated flow formed in the presence of a concave corner in a supersonic stream is studied. The strong\\u000a influence of the temperature factor on the separation zone length and the flow-generated aerodynamic characteristics is established.\\u000a It

V. Ya. Neiland; L. A. Sokolov; V. V. Shvedchenko

2008-01-01

223

Factors influencing the use of high-temperature sprinklers  

Microsoft Academic Search

High-temperature sprinklers—when and where to use them—are a subject of interest to fire protection engineers. In a series\\u000a of small-scale and large-scale fire tests, Underwriters' Laboratories, Inc., evaluated conditions under which high-temperature\\u000a sprinklers should and should not be used. The value of increasing water supply pressure to sprinklers of ordinary rating was\\u000a also investigated.

Miles R. Suchomel

1965-01-01

224

The effects and correction of the geometric factor for the POES/MEPED electron flux instrument using a multisatellite comparison  

NASA Astrophysics Data System (ADS)

Measurements from the Polar-Orbiting Environmental Satellite (POES) Medium Energy Proton and Electron Detector (MEPED) instrument are widely used in studies into radiation belt dynamics and atmospheric coupling. However, this instrument has been shown to have a complex energy-dependent response to incident particle fluxes, with the additional possibility of low-energy protons contaminating the electron fluxes. We test the recent Monte Carlo theoretical simulation of the instrument by comparing the responses against observations from an independent experimental data set. Our study examines the reported geometric factors for the MEPED electron flux instrument against the high-energy resolution Instrument for Detecting Particles (IDPs) on the Detection of Electromagnetic Emissions Transmitted from Earthquake Regions satellite when they are located at similar locations and times, thereby viewing the same quasi-trapped population of electrons. We find that the new Monte Carlo-produced geometric factors accurately describe the response of the POES MEPED instrument. We go on to develop a set of equations such that integral electron fluxes of a higher accuracy are obtained from the existing MEPED observations. These new MEPED integral fluxes correlated very well with those from the IDP instrument (>99.9% confidence level). As part of this study we have also tested a commonly used algorithm for removing proton contamination from MEPED instrument observations. We show that the algorithm is effective, providing confirmation that previous work using this correction method is valid.

Whittaker, Ian C.; Rodger, Craig J.; Clilverd, Mark A.; Sauvaud, Jean-André

2014-08-01

225

Basic factors controlling pest in high temperature systems  

NASA Technical Reports Server (NTRS)

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.

Berkowitz-Mattuck, J.; Rossetti, M.

1971-01-01

226

The effect of temperature on the formation resistivity factor of porous media  

E-print Network

FIGURES Figurc Page 1. Schematic of Pressure Cell, Electrical Circuit, and Auxiliary Equipment 2. The Chanoe in Core Conductivity as a Function of Brine Conductivity and Temperature - Paluxy Sand 18 3. The Change in Core Conductivity as a Functior... of. thc: measuremcnts were nmde unde r ambient ccn- ditions. Trrcse empirical resrl! s a c rpr)11cd to electric log in- tc:rpzctatio:rs without any correction for reservoir temperature and pressure. To date, there have been only a few published...

Brannan, Geryl Owen

2012-06-07

227

Optimizing Power Factor Correction  

E-print Network

and on the same type of map in Fig. 11. The contour lines are lines of constant annual saving. Dark areas represent annual savings of $1,2S9/yr to $1,S8S/yr, $1,99S/yr to $2,SI2/yr, $3,162/yr to $3,98l/yr, $S,012/yr to $6,310/yr, $7,943/yr to $10,000/yr... and multiples of 10 and 100 times these, Light areas represent annual savings of $l,OOO/yr to $1,259/yr, $1,585/yr to $1,99S/yr, $2,5l2/yr to $3,162/yr, $3,98l/yr to $S,012/yr, $6,310/yr to $7,943/yr and multiples of 10 and 100 times these. The maximum...

Phillips, R. K.; Burmeister, L. C.

228

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)

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.

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

2003-01-01

229

Epidermal growth factor and temperature regulate keratinocyte differentiation  

Microsoft Academic Search

The limited life-span and irregularities in epidermal differentiation and barrier function that have restricted the\\u000a utility of presently available skin culture models for pharmacological and toxicological studies indicate that further modifications\\u000a of culture conditions are required for optimization of these models. In the present study epidermis reconstructed on de-epidermized\\u000a dermis was used to investigate the effects of temperature and epidermal

Maria Ponec; Susan Gibbs; Arij Weerheim; Johanna Kempenaar; Aat Mulder; A. Mieke Mommaas

1997-01-01

230

Anomalous Temperature Dependence of the Quality Factor in a Superconducting Coplanar Waveguide Resonator  

NASA Astrophysics Data System (ADS)

We present the measurements of the temperature dependence of the internal quality factor (Qi) of a microwave resonator, well below the superconducting transition temperature. The device is a quarter-wavelength niobium (Tc = 9.2 K) coplanar waveguide resonator. The measured |S21| parameter shows typically the skewed Lorentzian distributions, from which the fitted quality factor monotonically decreases with the temperature increasing from 30 mK to 900 mK. It is observed that for the lower temperature range (i.e., at T < 700 mK) the temperature dependence of the fitted Qi deviates significantly from the predictions of the usual Mattis—Bardeen theory. The measured 3 dB internal quality factor Q'i also verifies such an anomalous temperature dependence. Physically, this phenomenon could be attributed dominantly to the effects of the two-level systems in the device, rather than the usual temperature-dependent complex conductance.

Zhou, Pin-Jia; Wang, Yi-Wen; Wei, Lian-Fu

2014-06-01

231

Factors Controlling Elevated Temperature Strength Degradation of Silicon Carbide Composites  

NASA Technical Reports Server (NTRS)

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.

2005-01-01

232

Dependence of Yb-169 absorbed dose energy correction factors on self-attenuation in source material and photon buildup in water  

SciTech Connect

Purpose: Absorbed dose energy correction factors, used to convert the absorbed dose deposited in a LiF thermoluminescent dosimeter (TLD) into the clinically relevant absorbed dose to water, were obtained for both spherical volumetric sources and for the model 4140 HDR Yb-169 source. These correction factors have a strong energy dependence below 200 keV; therefore, spectral changes were quantified as Yb-169 photons traveled through both source material (Yb{sub 2}O{sub 3}) and water with the corresponding absorbed dose energy correction factors, f(r,{theta}), calculated as a function of location in a phantom. Methods: Using the MCNP5 Monte Carlo radiation transport simulation program, the Yb-169 spectrum emerging from spherical Yb{sub 2}O{sub 3} sources (density 6.9 g/cm{sup 3}) with radii between 0.2 and 0.9 mm were analyzed and their behavior compared against those for a point-source. The absorbed dose deposited to both LiF and H{sub 2}O materials was analyzed at phantom depths of 0.1-10 cm for each source radius and the absorbed dose energy correction factor calculated as the ratio of the absorbed dose to water to that of LiF. Absorbed dose energy correction factors for the Model 4140 Yb-169 HDR brachytherapy source similarly were obtained and compared against those calculated for the Model M-19 Ir-192 HDR source. Results: The Yb-169 average spectral energy, emerging from Yb{sub 2}O{sub 3} spherical sources 0.2-0.9 mm in radius, was observed to harden from 7% to 29%; as these photons traveled through the water phantom, the photon average energy softened by as much as 28% at a depth of 10 cm. Spectral softening was dependent on the measurement depth in the phantom. Energy correction factors were found to vary both as a function of source radius and phantom depth by as much as 10% for spherical Yb{sub 2}O{sub 3} sources. The Model 4140 Yb-169 energy correction factors depended on both phantom depth and reference angle and were found to vary by more than 10% between depths of 1 and 10 cm and angles of 0 deg. and 180 deg. This was in contrast to that of the Model M-19 Ir-192 source which exhibited approximately 3.5%-4.4% variation in its energy correction factors from phantom depths of 0.5-10 cm. The absorbed dose energy correction factor for the Ir-192 source, on the other hand, was independent of angle to within 1%. Conclusions: The application of a single energy correction factor for Yb-169 TLD based dosimetry would introduce a high degree of measurement uncertainty that may not be reasonable for the clinical characterization of a brachytherapy source; rather, an absorbed dose energy correction function will need to be developed for these sources. This correction function should be specific to each source model, type of TLD used, and to the experimental setup to obtain accurate and precise dosimetric measurements.

Medich, David C.; Munro, John J. III [Radiation Laboratory, University of Massachusetts Lowell, 1 University Avenue, Lowell, Massachusetts 01854 (United States); Source Production and Equipment Co., Inc., 113 Teal Street, St. Rose, Louisiana 70087 (United States)

2010-05-15

233

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

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

234

Power factor correction of non-linear loads employing a single phase active power filter: control strategy, design methodology and experimentation  

Microsoft Academic Search

This paper presents a technique for single phase power factor correction of nonlinear loads employing an active power filter. The current control strategy is the same used in the boost pre-regulator, which is the average current mode technique. The paper focuses on the design methodology and the analysis of the control strategy which allows the compensation of harmonics and phase

Fabiana Pottker; Ivo Barbi

1997-01-01

235

Polyvinyl alcohol as a useful indicator on iodometry. (II): Temperature dependence of iodine recovery and the correction method of iodine concentration in the lower detection limit region.  

PubMed

In an iodometric titration method for iodine (or chlorine) analysis, the percent recovery of iodine (or chlorine) decreases in the low concentration region and at the relatively higher temperature range. We have shown that the percent recovery vs. concentration curve can be expressed by a simple empirical formula. The empirical formula contains parameters that depend on temperature and those parameters were obtained as a function of temperature. The empirical formula can be used as a correction function for experimental iodine (or chlorine) concentrations. By applying the correction function with the parameters to the experimentally obtained concentrations, we can estimate the reliable concentration in the low concentration region. Estimated concentrations were within 10% (as RSD) of the exact values after the correction in the range of 0.4 mg I2 L(-1) ([triple bond] ca. 0.1 mg as Cl2 L9-1)) - 4.4 mg I2 L(-1) ([triple bond] ca. 1.2 mg as Cl2 L(-1)) in the temperature range of 0 to 30 degrees C. PMID:15068303

Yoshinaga, Tetsutaro; Tsuchida, Makoto; Toyose, Yasushi; Hiratsuka, Hiroshi; Yamaye, Makoto

2004-03-01

236

Correction factors for the NMi free-air ionization chamber for medium-energy x-rays calculated with the Monte Carlo method.  

PubMed

A new method is described for the determination of x-ray quality dependent correction factors for free-air ionization chambers. The method is based on weighting correction factors for mono-energetic photons, which are calculated using the Monte Carlo method, with measured air kerma spectra. With this method, correction factors for electron loss, scatter inside the chamber and transmission through the diaphragm and front wall have been calculated for the NMi free-air chamber for medium-energy x-rays for a wide range of x-ray qualities in use at NMi. The newly obtained correction factors were compared with the values in use at present, which are based on interpolation of experimental data for a specific set of x-ray qualities. For x-ray qualities which are similar to this specific set, the agreement between the correction factors determined with the new method and those based on the experimental data is better than 0.1%, except for heavily filtered x-rays generated at 250 kV. For x-ray qualities dissimilar to the specific set, differences up to 0.4% exist, which can be explained by uncertainties in the interpolation procedure of the experimental data. Since the new method does not depend on experimental data for a specific set of x-ray qualities, the new method allows for a more flexible use of the free-air chamber as a primary standard for air kerma for any x-ray quality in the medium-energy x-ray range. PMID:9832012

Grimbergen, T W; van Dijk, E; de Vries, W

1998-11-01

237

Retrieving water surface temperature from archive LANDSAT thermal infrared data: Application of the mono-channel atmospheric correction algorithm over two freshwater reservoirs  

NASA Astrophysics Data System (ADS)

Water surface temperature is a key element in characterizing the thermodynamics of waterbodies, and for irregularly-shaped inland reservoirs, LANDSAT thermal infrared images are the best alternative yet for the retrieval of this parameter. However, images must be corrected mainly for atmospheric effects in order to be fully exploitable. The objective of this study is to validate the mono-channel correction algorithm for single-band thermal infrared LANDSAT data as put forward by Jiménez-Muñoz et al. (2009). Two freshwater reservoirs in continental France were selected as study sites, and best use was made of all accessible image and field data. Results obtained are satisfactory and in accordance with the literature: r2 values are above 0.90 and root-mean-square error values are comprised between 1 and 2 °C. Moreover, paired Wilcoxon signed rank tests showed a highly significant difference between field and uncorrected image data, a very highly significant difference between uncorrected and corrected image data, and no significant difference between field and corrected image data. The mono-channel algorithm is hence recommended for correcting archive LANDSAT single-band thermal infrared data for inland waterbody monitoring and study.

Simon, R. N.; Tormos, T.; Danis, P.-A.

2014-08-01

238

Vascular endothelial growth factor corrected for platelet count and hematocrit is associated with the clinical course of aplastic anemia in children.  

PubMed

The wide variety of clinical courses that lead to the development of severe aplastic anemia (AA) makes it difficult to speculate whether treatment for AA is required in the early phase. The objective of this study was to identify a method for predicting the clinical course of AA at the onset of the disease. First, in healthy adults, vascular endothelial growth factor (VEGF) released per platelet was measured by the activation of platelet-rich plasma (PRP) and platelet-poor plasma (PPP). Serum concentration of VEGF, serum concentration of VEGF corrected for platelet count, and serum concentration of VEGF corrected for both platelet count and hematocrit (corrected VEGF) were then compared to VEGF released per platelet. Corrected VEGF showed the best correlation with VEGF released per platelet by the activation of PRP in healthy subjects (R (2) = in a single 0.806, p = 0.001). Next, corrected VEGF was assayed in 11 pediatric patients with AA at the time of diagnosis. Corrected VEGF in AA patients was significantly greater than that in age-matched control subjects [1.32 × 10(-6) pg (range 0.36-1.85) vs. 0.18 × 10(-6) pg (range 0.12-0.94)] (p = 0.002). Moreover, corrected VEGF in AA patients who did not require treatment for more than 2 years was significantly greater than that in AA patients who required earlier treatment [1.67 × 10(-6) pg (range 1.32-1.85) vs. 0.87 × 10(-6) pg (0.36-1.34)] (p = 0.011). These data indicate that a compensatory mechanism for increasing VEGF and preventing disease progression might play a role in AA. Corrected VEGF may be useful for predicting the clinical course of AA. PMID:22527851

Kodama, Yuichi; Okamoto, Yasuhiro; Hashiguchi, Teruto; Shinkoda, Yuichi; Nishikawa, Takuro; Tanabe, Takayuki; Kawano, Yoshifumi

2012-05-01

239

Factors contributing to the temperature beneath plaster or fiberglass cast material  

Microsoft Academic Search

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,

Michael J Hutchinson

2008-01-01

240

Factors That Affect Riverbank Filtrate Water Temperature in Daesan Plants, Changwon, Korea  

Microsoft Academic Search

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

J. Shin; J. Lim; K. Lee; W. Jung; H. Kim

2008-01-01

241

674 BULLETIN OF THE BUREAU OF FISHERIES FACTORS GOVERNING THE TEMPERATURE OF THE  

E-print Network

The temperature of the gulf, like that of other boreal seas, is governed by a. complex of factors into which. The absorption of heat by the water from warm air blowing over its surface exerts much less effect on the sea temperature. This last statement rests on the fact that the capacity of sea water for heat (technically its

242

A Temperature Dependent Correction to the Model for Microwave Excess Emissivity of the Ocean due to Surface Winds  

E-print Network

speed. This temperature dependence is a residual result of the dependence of the specular ocean surface is proportionately larger at higher temperatures. INTRODUCTION Surface winds raise the microwave emissivity- optimal performance. Sea surface temperature was restricted to be greater than 275 Kelvins. This was done

Ruf, Christopher

243

Temperature and density dependence of the electron Landé g factor in semiconductors  

Microsoft Academic Search

The temperature and density dependence of spin quantum beats of electrons is measured by time-resolved photoluminescence spectroscopy and yields the electron Landé g factor in bulk GaAs, InP, and CdTe. In GaAs the g factor increases linearly from -0.44 at 4 K to -0.30 at 280 K; in InP the g factor is 1.20 at 4 K, exhibiting a very

M. Oestreich; S. Hallstein; A. P. Heberle; K. Eberl; E. Bauser; W. W. Rühle

1996-01-01

244

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

SciTech Connect

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.

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

1993-09-01

245

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

SciTech Connect

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.

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

1993-05-01

246

Helpful hints to select a power-factor-correction solution for low- and medium-power single-phase power supplies  

Microsoft Academic Search

This work presents a review of power-factor-correction (PFC) circuits for low- and medium-power single-phase power supplies. The main idea is not just to show the state of the art of this topic but to select the most interesting topologies for each application depending on the power level, the input voltage range, and the output voltage. Since IEC 61000-3-2 regulations came

Arturo Fernández; Javier Sebastián; Marta María Hernando; Pedro Villegas; Jorge García

2005-01-01

247

Correcting the spectroscopic surface gravity using transits and asteroseismology. No significant effect on temperatures or metallicities with ARES+MOOG in LTE  

E-print Network

Precise stellar parameters are crucial for several reasons, amongst which are the precise characterization of orbiting exoplanets and the correct determination of galactic chemical evolution. The atmospheric parameters are extremely important because all the other stellar parameters depend on them. Using our standard equivalent-width method on high-resolution spectroscopy, good precision can be obtained for the derived effective temperature and metallicity. The surface gravity, however, is usually not well constrained with spectroscopy. We use two different samples of FGK dwarfs to study the effect of the stellar surface gravity on the precise spectroscopic determination of the other atmospheric parameters. Furthermore, we present a straightforward formula for correcting the spectroscopic surface gravities derived by our method and with our linelists. Our spectroscopic analysis is based on Kurucz models in LTE, performed with the MOOG code to derive the atmospheric parameters. The surface gravity was either l...

Mortier, A; Adibekyan, V Zh; Brandão, I M; Santos, N C

2014-01-01

248

A trapezoid approach for the experimental total-to-peak efficiency curve used in the determination of true coincidence summing correction factors in a HPGe detector  

NASA Astrophysics Data System (ADS)

In this work, a simple method for true coincidence correction is suggested for a voluminous source measured in close detection geometry for a HPGe detector. TrueCoinc program based on Sudár's algorithm was used to determine true coincidence summing correction (TCS) factors by using full energy peak (FEP) efficiency, and total-to-peak (TTP) efficiency curves in which experimental efficiencies are obtained from almost coincident-free radionuclides such as 54Mn, 57Co, 65Zn, 109Cd, 137Cs and 241Am. In order to calculate TTP efficiency curve three different approaches were tested. One of them is new and here called trapezoid approach which was used successfully in determining total count of spectrum for the TTP efficiency curves. According to different TTP determination methods, the changes in true coincidence factors are observed. The FEP efficiency curves are also established for a cylindrical source. Then, TCS factors were determined for the particular peaks of daughters of 226Ra, 238U, and 232Th using the suggested method. Those activities measured from some certified reference materials such as IAEA RGU-1 and RGTh-1 are used to validate the present TCS correction procedure.

?ahiner, Eren; Meriç, Niyazi

2014-03-01

249

A robust approach to correct for pronounced errors in temperature measurements by controlling radiation damping feedback fields in solution NMR  

NASA Astrophysics Data System (ADS)

Accurate temperature measurement is a requisite for obtaining reliable thermodynamic and kinetic information in all NMR experiments. A widely used method to calibrate sample temperature depends on a secondary standard with temperature-dependent chemical shifts to report the true sample temperature, such as the hydroxyl proton in neat methanol or neat ethylene glycol. The temperature-dependent chemical shift of the hydroxyl protons arises from the sensitivity of the hydrogen-bond network to small changes in temperature. The frequency separation between the alkyl and the hydroxyl protons are then converted to sample temperature. Temperature measurements by this method, however, have been reported to be inconsistent and incorrect in modern NMR, particularly for spectrometers equipped with cryogenically-cooled probes. Such errors make it difficult or even impossible to study chemical exchange and molecular dynamics or to compare data acquired on different instruments, as is frequently done in biomolecular NMR. In this work, we identify the physical origins for such errors to be unequal amount of dynamical frequency shifts on the alkyl and the hydroxyl protons induced by strong radiation damping (RD) feedback fields. Common methods used to circumvent RD may not suppress such errors. A simple, easy-to-implement solution was demonstrated that neutralizes the RD effect on the frequency separation by a "selective crushing recovery" pulse sequence to equalize the transverse magnetization of both spin species. Experiments using cryoprobes at 500 MHz and 800 MHz demonstrated that this approach can effectively reduce the errors in temperature measurements from about ±4.0 K to within ±0.4 K in general.

Wolahan, Stephanie M.; Li, Zhao; Hsu, Chao-Hsiung; Huang, Shing-Jong; Clubb, Robert; Hwang, Lian-Pin; Lin, Yung-Ya

2014-11-01

250

Correcting artifacts in transition to a wound optic fiber: Example from high-resolution temperature profiling in the Dead Sea  

NASA Astrophysics Data System (ADS)

resolution fiber-optic cables allow for detailed observation of thermally complex heterogeneous hydrologic systems. A commercially produced high spatial resolution helically wound optic fiber sensing cable is employed in the Dead Sea, in order to study the dynamics of thermal stratification of the hypersaline lake. Structured spatial artifacts were found in the data from the first 10 m of cable (110 m of fiber length) following the transition from straight fiber optic. The Stokes and Anti-Stokes signals indicate that this is the result of differential attenuation, thought to be due to cladding losses. Though the overall spatial form of the loss was consistent, the fine structure of the loss changed significantly in time, and was strongly asymmetrical, and thus was not amenable to standard calibration methods. Employing the fact that the cable was built with a duplex construction, and using high-precision sensors mounted along the cable, it was possible to correct the artifact in space and time, while retaining the high-quality of data obtained in the early part of the cable (prior to significant optical attenuation). The defect could easily be overlooked; however, reanalyzing earlier experiments, we have observed the same issue with installations employing similar cables in Oregon and France, so with this note we both alert the community to this persistent concern and provide an approach to correct the data in case of similar problems.

Arnon, Ali; Selker, John; Lensky, Nadav

2014-06-01

251

Factor Structures of the Original and Brief Fear of Negative Evaluation (FNE and BFNE) Scales: Correction to an Erroneous Footnote  

Microsoft Academic Search

In recent factor analyses of the original and brief Fear of Negative Evaluation (FNE and BFNE) scales, a 2-factor model was supported, with straightforwardly worded and reverse-worded items loading on separate factors (T. L. Rodebaugh et al., 2004). However, a theoretically meaningful alternative model was not fitted previously because the authors mistakenly assumed that unique variances among categorical manifest variables

Carol M. Woods; Thomas L. Rodebaugh

2005-01-01

252

A correction factor for ablation algorithms assuming deviations of Lambert-Beer's law with a Gaussian-profile beam  

NASA Astrophysics Data System (ADS)

In this work, we propose an adjustment factor to be considered in ablation algorithms used in refractive surgery. This adjustment factor takes into account potential deviations of Lambert-Beer's law and the characteristics of a Gaussian-profile beam. To check whether the adjustment factor deduced is significant for visual function, we applied it to the paraxial Munnerlyn formula and found that it significantly influences the post-surgical corneal radius and p-factor. The use of the adjustment factor can help reduce the discrepancies in corneal shape between the real data and corneal shape expected when applying laser ablation algorithms.

Rodríguez-Marín, Francisco; Anera, Rosario G.; Alarcón, Aixa; Hita, E.; Jiménez, J. R.

2012-04-01

253

High-temperature measurements of Q-factor in rotated X-cut quartz resonators  

NASA Technical Reports Server (NTRS)

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.

Fritz, I. J.

1981-01-01

254

Location specific forecasting of maximum and minimum temperatures over India by using the statistical bias corrected output of global forecasting system  

NASA Astrophysics Data System (ADS)

The output from Global Forecasting System (GFS) T574L64 operational at India Meteorological Department (IMD), New Delhi is used for obtaining location specific quantitative forecast of maximum and minimum temperatures over India in the medium range time scale. In this study, a statistical bias correction algorithm has been introduced to reduce the systematic bias in the 24-120 hour GFS model location specific forecast of maximum and minimum temperatures for 98 selected synoptic stations, representing different geographical regions of India. The statistical bias correction algorithm used for minimizing the bias of the next forecast is Decaying Weighted Mean (DWM), as it is suitable for small samples. The main objective of this study is to evaluate the skill of Direct Model Output (DMO) and Bias Corrected (BC) GFS for location specific forecast of maximum and minimum temperatures over India. The performance skill of 24-120 hour DMO and BC forecast of GFS model is evaluated for all the 98 synoptic stations during summer (May-August 2012) and winter (November 2012-February 2013) seasons using different statistical evaluation skill measures. The magnitude of Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE) for BC GFS forecast is lower than DMO during both summer and winter seasons. The BC GFS forecasts have higher skill score as compared to GFS DMO over most of the stations in all day-1 to day-5 forecasts during both summer and winter seasons. It is concluded from the study that the skill of GFS statistical BC forecast improves over the GFS DMO remarkably and hence can be used as an operational weather forecasting system for location specific forecast over India.

Durai, V. R.; Bhardwaj, Rashmi

2014-06-01

255

Perturbative renormalization factors and O(a^2) corrections for lattice 4-fermion operators with improved fermion\\/gluon actions  

Microsoft Academic Search

In this work we calculate the corrections to the amputated Green's functions\\u000aof 4-fermion operators, in 1-loop Lattice Perturbation theory. One of the novel\\u000aaspects of our calculations is that they are carried out to O(a^2) (a: lattice\\u000aspacing). We employ the Wilson\\/clover action for massless fermions (also\\u000aapplicable for the twisted mass action in the chiral limit) and a

Martha Constantinou; Petros Dimopoulos; Roberto Frezzotti; Vittorio Lubicz; Haralambos Panagopoulos; Apostolos Skouroupathis; Fotos Stylianou

2010-01-01

256

Perturbative renormalization factors and O(a²) corrections for lattice four-fermion operators with improved fermion\\/gluon actions  

Microsoft Academic Search

In this work we calculate the corrections to the amputated Green's functions of four-fermion operators, in 1-loop lattice perturbation theory. One of the novel aspects of our calculations is that they are carried out to second order in the lattice spacing, O(a²). We employ the Wilson\\/clover action for massless fermions (also applicable for the twisted mass action in the chiral

Martha Constantinou; Haralambos Panagopoulos; Apostolos Skouroupathis; Fotos Stylianou; Petros Dimopoulos; Roberto Frezzotti; Vittorio Lubicz

2011-01-01

257

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...

258

The correctness to the spuriously simulated semi-annual cycle of the sea surface temperature in the equatorial eastern Pacific  

Microsoft Academic Search

One of the challenges faced by the climate model of the Community Climate System Model version 3 (CCSM3) is the spuriously\\u000a simulated semi-annual cycle of the sea surface temperature (SST) in the equatorial eastern Pacific. This model bias has limited\\u000a the performance of the climate simulation and prediction. Based on the surface wave-circulation coupled theory, an atmosphere-wave-ocean\\u000a coupled model was

ZhenYa Song; FangLi Qiao; ChunZai Wang

2011-01-01

259

Dependence on temperature and pixel threshold of the calibration for the Timepix detector and its correction method  

NASA Astrophysics Data System (ADS)

The semiconductor pixel detector Timepix (matrix of 256 × 256 pixels with 55 ?m pitch) can be used for measurements of energies of radiation quanta. For this purpose knowledge of the energy calibration of each pixel is required. Such a calibration is nonlinear. Two calibration methods already exist that use either monochromatic radiation sources or the internal test pulse capability. In the work we compare the calibrated response of the detector with the source method and for different temperatures and detector settings. Furthermore in this work we also explore the possibility of calibrating the detector under new conditions (temperature, detector settings) by adjusting an already existing calibration for different conditions. The new cross-temperature and cross-threshold calibration is calculated based on 3 original calibrations. This approach is advantageous, because it allows improving the detector response for different conditions without the need to make a whole new calibration. It is also the only appropriate method for particular applications where the detector is for instance placed in environments beyond direct physical access such as in a nuclear reactor vessel, the LHC ATLAS detector or in outer space. The method was applied and tested on a Timepix chip equipped with a 300 ?m thick Si sensor.

Turecek, D.; Jakubek, J.

2013-01-01

260

Factors contributing to the temperature beneath plaster or fiberglass cast material  

PubMed Central

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 minutes. Conclusion Clinicians should be cautious when applying thick casts with warm dip water. Fast setting plasters have increased risk of thermal injury while brand does not appear to play a significant role. Prefabricated fiberglass splints appear to be safer than circumferential casts. The greatest risk of thermal injury occurs when thick casts are allowed to mature while resting on pillow. PMID:18298851

Hutchinson, Michael J; Hutchinson, Mark R

2008-01-01

261

High Temperature as a Risk Factor for Infectious Diarrhea in Shanghai, China  

PubMed Central

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

Zhou, Xiaodan; Zhou, Yanbing; Chen, Renjie; Ma, Wenjuan; Deng, Haiju; Kan, Haidong

2013-01-01

262

A New Method to Measure Temperature and Burner Pattern Factor Sensing for Active Engine Control  

NASA Technical Reports Server (NTRS)

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.

Ng, Daniel

1999-01-01

263

Proteomic comparison of Ralstonia solanacearum strains reveals temperature dependent virulence factors  

PubMed Central

Background Ralstonia solanacearum, the causal agent of bacterial wilt, is a genetically diverse bacterial plant pathogen present in tropical and subtropical regions of the world that infects more than 200 plant species, including economically important solanaceous crops. Most strains of R. solanacearum are only pathogenic at temperatures between 25 to 30°C with strains that can cause disease below 20°C considered a threat to agriculture in temperate areas. Identifying key molecular factors that distinguish strains virulent at cold temperatures from ones that are not is needed to develop effective management tools for this pathogen. We compared protein profiles of two strains virulent at low temperature and two strains not virulent at low temperature when incubated in the rhizosphere of tomato seedlings at 30 and 18°C using quantitative 2D DIGE gel methods. Spot intensities were quantified and compared, and differentially expressed proteins were sequenced and identified by mass spectrometry (MS/MS). Results Four hundred and eighteen (418) differentially expressed protein spots sequenced produced 101 unique proteins. The identified proteins were classified in the Gene Ontology biological processes categories of metabolism, cell processes, stress response, transport, secretion, motility, and virulence. Identified virulence factors included catalase (KatE), exoglucanase A (ChbA), drug efflux pump, and twitching motility porin (PilQ). Other proteins identified included two components of a putative type VI secretion system. We confirmed differential expression of 13 candidate genes using real time PCR techniques. Global regulators HrpB and HrpG also had temperature dependent expression when quantified by real time PCR. Conclusions The putative involvement of the identified proteins in virulence at low temperature is discussed. The discovery of a functional type VI secretion system provides a new potential virulence mechanism to explore. The global regulators HrpG and HrpB, and the protein expression profiles identified suggest that virulence at low temperatures can be partially explained by differences in regulation of virulence factors present in all the strains. PMID:24725348

2014-01-01

264

Monte Carlo modelling of diode detectors for small field MV photon dosimetry: detector model simplification and the sensitivity of correction factors to source parameterization  

NASA Astrophysics Data System (ADS)

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_{\\det _{MC} }^{f_{clin} }) 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_{det_{MC} }^{f_{clin} }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 (\\mathop k\

Cranmer-Sargison, G.; Weston, S.; Evans, J. A.; Sidhu, N. P.; Thwaites, D. I.

2012-08-01

265

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

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. PMID:25185754

Shaikh, Nisar A; Yantha, Jason; Shaikh, Sabah; Rowe, William; Laidlaw, Maggie; Cockerline, Carla; Ali, Abbas; Holub, Bruce; Jackowski, George

2014-11-01

266

Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation, 1945--1947. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

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.

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

1993-12-01

267

WINDOW-WALL INTERFACE CORRECTION FACTORS: THERMAL MODELING OF INTEGRATED FENESTRATION AND OPAQUE ENVELOPE SYSTEMS FOR IMPROVED PREDICTION OF ENERGY USE  

SciTech Connect

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

Bhandari, Mahabir S [ORNL] [ORNL; Ravi, Dr. Srinivasan [University of Florida, Gainesville] [University of Florida, Gainesville

2012-01-01

268

Non-reference condition correction factor kNR of typical radiation detectors applied for the dosimetry of high-energy photon fields in radiotherapy.  

PubMed

According to accepted dosimetry protocols, the "radiation quality correction factor"k(Q) accounts for the energy-dependent changes of detector responses under the conditions of clinical dosimetry for high-energy photon radiations. More precisely, a factor k(QR) is valid under reference conditions, i.e. at a point on the beam axis at depth 10 cm in a large water phantom, for 10×10 cm(2) field size, SSD 100 cm and the given radiation quality with quality index Q. Therefore, a further correction factor k(NR) has been introduced to correct for the influences of spectral quality changes when detectors are used under non-reference conditions such as other depths, field sizes and off-axis distances, while under reference conditions k(NR) is normalized to unity. In this paper, values of k(NR) are calculated for 6 and 15 MV photon beams, using published data of the energy-dependent responses of various radiation detectors to monoenergetic photon radiations, and weighting these responses with validated photon spectra of clinical high-energy photon beams from own Monte-Carlo-calculations for a wide variation of the non-reference conditions within a large water phantom. Our results confirm the observation by Scarboro et al. [26] that k(NR) can be represented by a unique function of the mean energy Em, weighted by the spectral photon fluence. Accordingly, the numerical variations of Em with depth, field size and off-axis distance have been provided. Throughout all considered conditions, the deviations of the k(NR) values from unity are at most 2% for a Farmer type ion chamber, and they remain below 15% for the thermoluminescent detectors LiF:Mg,Ti and LiF:Mg,Cu,P. For the shielded diode EDP-10, k(NR) varies from unity up to 20%, while the unshielded diode EDD-5 shows deviations up to 60% in the peripheral region. Thereby, the restricted application field of unshielded diodes has been clarified. For small field dosimetry purposes k(NR) can be converted into k(NCSF), the non-calibration condition correction factor normalized to unity for a 4×4 cm(2) calibration field. For the unshielded Si diodes needed in small-field dosimetry, the values of k(NCSF) are closer to unity than the associated k(NR) values. PMID:22658451

Chofor, Ndimofor; Harder, Dietrich; Poppe, Björn

2012-09-01

269

Perturbative renormalization factors and O(a^2) corrections for lattice 4-fermion operators with improved fermion/gluon actions  

E-print Network

In this work we calculate the corrections to the amputated Green's functions of 4-fermion operators, in 1-loop Lattice Perturbation theory. One of the novel aspects of our calculations is that they are carried out to O(a^2) (a: lattice spacing). We employ the Wilson/clover action for massless fermions (also applicable for the twisted mass action in the chiral limit) and a family of Symanzik improved actions for gluons. Our calculations have been carried out in a general covariant gauge. Results have been obtained for several popular choices of values for the Symanzik coefficients. While our Green's function calculations regard any pointlike 4-fermion operators which do not mix with lower dimension ones, we pay particular attention to DF=2 operators, both Parity Conserving and Parity Violating (F: flavour). We compute the perturbative renormalization constants for a complete basis of 4-fermion operators and we study their mixing pattern. For some of the actions considered here, even O(a^0) results did not exist in the literature to date. The correction terms which we calculate are essential ingredients for minimizing the lattice artifacts which are present in non-perturbative evaluations of renormalization constants with the RI'-MOM method. Our perturbative results, for the matrix elements of DF=2 operators and for the corresponding renormalization matrices, depend on a large number of parameters: coupling constant, number of colors, lattice spacing, external momentum, clover parameter, Symanzik coefficients, gauge parameter. To make these results most easily accessible, we have included them in the distribution package of this paper, as an ASCII file named: 4-fermi.m; the file is best perused as Mathematica input. The main results of this work have been applied to improve non-perturbative estimates of the B_K-parameter in N_F=2 twisted mass lattice QCD.

Martha Constantinou; Petros Dimopoulos; Roberto Frezzotti; Vittorio Lubicz; Haralambos Panagopoulos; Apostolos Skouroupathis; Fotos Stylianou

2010-11-28

270

The Aquarius Scatterometer: An Active System for Measuring Surface Roughness for Sea-Surface Brightness Temperature Correction  

NASA Technical Reports Server (NTRS)

The Aquarius scatterometer is a total-power L-band radar system for estimating ocean surface roughness. Its measurements will enable the removal of wind effects from the Aquarius radiometer ocean-surface brightness temperature measurements being used to retrieve ocean salinity. The Aquarius scatterometer is a relatively simple, low-spatial resolution power-detecting radar, without ranging capability. But to meet its science requirement, it must be very stable, with repeatability on the order of 0.1 dB over several days, and calibrated accuracy to this level over several months. Data from this instrument over land as well as ocean areas will be available for a variety of geophysical applications.

Freedman, Adam; McWatters, Dalia; Spencer, Michael

2006-01-01

271

Thermoelectric power factors of nanocarbon ensembles as a function of temperature  

NASA Astrophysics Data System (ADS)

Thermoelectric power factors of nanocarbon ensembles have been determined as a function of temperature from 400 to 1200 K. The ensembles, composed of mixtures of nanographite or disperse ultrananocrystalline diamond with B4C, are formed into mechanically rigid compacts by reaction at 1200 K with methane gas and subsequently annealed in an argon atmosphere at temperatures up to 2500 K. The ensembles were characterized using scanning electron microscopy, Raman, x-ray diffraction, and high resolution transmission electron microscopy techniques and found to undergo profound nanostructural changes as a function of temperature while largely preserving their nanometer sizes. The power factors increase strongly both as a function of annealing temperature and of the temperature at which the measurements are carried out reaching 1 ?W/K2 cm at 1200 K without showing evidence of a plateau. Density functional "molecular analog" calculations on systems based on stacked graphene sheets show that boron substitutional doping results in a lowering of the Fermi level and the creation of a large number of hole states within thermal energies of the Fermi level [P. C. Redfern, D. M. Greun, and L. A. Curtiss, Chem. Phys. Lett. 471, 264 (2009)]. We propose that enhancement of electronic configurational entropy due to the large number of boron configurations in the graphite lattice contributes to the observed thermoelectric properties of the ensembles.

Gruen, D. M.; Bruno, P.; Arenal, R.; Routbort, J.; Singh, D.; Xie, M.

2009-04-01

272

An improved DTC for matrix converter drives using multi-mode ISVM and unity input power factor correction  

Microsoft Academic Search

This paper presents an improved direct torque control (DTC) method for sensorless matrix converter drives using a multi-mode indirect space vector modulation (ISVM) and an adaptive sliding mode observer. The drive system is characterized by reduced torque and flux ripples, unity input power factor, sinusoidal input\\/output waveforms and good sensorless control performance over a wide speed range, while maintaining constant

D. Xiao; F. Rahman

2009-01-01

273

Real-time prediction of earthquake ground motion: application of data assimilation and real-time correction of site amplification factors  

NASA Astrophysics Data System (ADS)

In this presentation, I explain the data assimilation technique and real-time correction of frequency-dependent site amplification factor for time evolutional prediction of seismic ground motion (waveforms) which is applicable to Earthquake Early Warning (EEW). At present, many methods of EEW determine hypocenter and magnitude (source parameters) rapidly at first, and then ground motion is predicted using the hypocenter and magnitude. The warnings are issued depending on the strength of the predicted ground motion. In this method, however, it is not easy to take source extent and the effects of rupture directivity into account. Although S-wave arrival does not necessary means the start of the strong motion for large earthquakes as experienced during the 2011 Tohoku earthquake (Mw9.0), it is hard to predict the time evolution of ground motion strength. In general, wave motion is predictable when boundary condition and initial condition are given. Time evolutional prediction is a method based on this approach using the current wavefield as an initial condition, that is u(x, t+?t)=P(u(x, t)), where u is the wave motion at location x at lapse time t, and P is the prediction operator. Future wave motion, u(x, t+?t), is predicted using P from the distribution of the current wavefield, u(x, t). For P, finite difference technique or boundary integral equation method, such as Kirchhoff integral, is used. The time evolutional prediction enables us to predict the time evolution of ground motion strength. In the time evolutional prediction, determination of detailed distribution of current wave motion is a key, so that dense seismic observation network is required. Data assimilation is a technique to produce artificially denser network, which is widely used for numerical weather forecast and oceanography. Distribution of current wave motion is estimated from not only the current actual observation of u(x, t), but also the prediction of one step before, P(u(x, t-?t)). Combination of them produces denser artificial network than the real one. Data assimilation is a powerful technique for time evolutional prediction. For actual application, however, site amplification factors should be corrected beforehand. Site factors are usually frequency-dependent, and the frequency dependence should be corrected in real time manner for EEW. The site factor is represented by a causal filter in time domain which is estimated from bilinear transform and pre-warping methods in digital filtering technique. Using the causal filter, the site amplification factor is corrected in real time manner. I will present some examples for the real time correction of the frequency-dependent site amplification factors to predict the waveforms. Instead of rapid estimation of hypocentral location and M, time evolutional prediction is a powerful method for real-time prediction of ground motion (waveform) for EEW, which is applicable even for cases of large source extent, strong rupture directivity, and/or multiple simultaneous sources.

Hoshiba, M.

2013-12-01

274

Correction of systematic model forcing bias of CLM using assimilation of cosmic-ray neutrons and land surface temperature: a study in the Heihe catchment, China  

NASA Astrophysics Data System (ADS)

The recent development of the non-invasive cosmic-ray soil moisture sensing technique fills the gap between point scale soil moisture measurements and regional scale soil moisture measurements by remote sensing. A cosmic-ray probe measures soil moisture for a footprint with a diameter of ~600 m (at sea level) and with an effective measurement depth between 12 and 76 cm, depending on the soil humidity. In this study, it was tested whether neutron counts also allow to correct for a systematic error in the model forcings. Lack of water management data often cause systematic input errors to land surface models. Here, the assimilation procedure was tested for an irrigated corn field (Heihe Watershed Allied Telemetry Experimental Research - HiWATER, 2012) where no irrigation data were available as model input although the area a significant amount of water was irrigated. Measured cosmic-ray neutron counts and Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) products were jointly assimilated into the Community Land Model (CLM) with the Local Ensemble Transform Kalman Filter. Different data assimilation scenarios were evaluated, with assimilation of LST and/or cosmic-ray neutron counts, and possibly parameter estimation of leaf area index (LAI). The results show that the direct assimilation of cosmic-ray neutron counts can improve the soil moisture and evapotranspiration (ET) estimation significantly, correcting for lack of information on irrigation amounts. The joint assimilation of neutron counts and LST could improve further the ET estimation, but the information content of neutron counts exceeded the one of LST. Additional improvement was achieved by calibrating LAI, which after calibration was also closer to independent field measurements. It was concluded that assimilation of neutron counts was useful for ET and soil moisture estimation even if the model has a systematic bias like neglecting irrigation. However, also the assimilation of LST helped to correct the systematic model bias introduced by neglecting irrigation and LST could be used to update soil moisture with state augmentation.

Han, X.; Hendricks Franssen, H.-J.; Rosolem, R.; Jin, R.; Li, X.; Vereecken, H.

2014-07-01

275

Determination of the beam quality correction factor k_{Q,Q_0 } for the microLion chamber in a clinical photon beam  

NASA Astrophysics Data System (ADS)

The mcroLion chamber, which has a small volume (0.0017cc) and a high sensitivity suitable for small field dosimetry, is an ionization chamber with liquid (isooctane) filling the cavity volume. In the present work, we used two alternative ways to estimate the beam quality correction factor k_{Q,Q_0 }^{micL} of the microLion chamber in the 6 MV photon beam from a Clinac iX accelerator (Varian, USA); Monte Carlo simulations and experimental methods. The Monte Carlo calculation (1.0183 ± 0.58%) agreed to within 0.56% with the experimental determination (1.024 ± 0.58%). The results from the two methods were in good agreement within acceptable uncertainties. We think that the averaged factor, 1.0212, could be used for the microLion chamber in reference dosimetry.

Choi, Sang Hyoun; Kim, Chan Hyeong; Huh, Hyun Do; Kim, Kum-Bae; Kim, SeongHoon

2013-01-01

276

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)

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 substantially the same in chest and heart muscle and are unchanged in these disease states. The mean value for T1 (PCr)/ T1(ATP) is 2.16 ± 0.29 SE.

Bottomley, Paul A.; Hardy, Christopher J.; Weiss, Robert G.

277

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

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 to be included in the model, (2) diode detectors of smaller active radius require less of a correction and (3) (k(fclin,fmsr)(Qclin,Qmsr)) is insensitive to the incident the electron energy and spot size variations investigated. Therefore, simplified detector models can be used with acceptable accuracy within the recently proposed small field dosimetry formalism. PMID:22842678

Cranmer-Sargison, G; Weston, S; Evans, J A; Sidhu, N P; Thwaites, D I

2012-08-21

278

Perturbative renormalization factors and O(a^2) corrections for lattice 4-fermion operators with improved fermion/gluon actions  

E-print Network

In this work we calculate the corrections to the amputated Green's functions of 4-fermion operators, in 1-loop Lattice Perturbation theory. One of the novel aspects of our calculations is that they are carried out to O(a^2) (a: lattice spacing). We employ the Wilson/clover action for massless fermions (also applicable for the twisted mass action in the chiral limit) and a family of Symanzik improved actions for gluons. Our calculations have been carried out in a general covariant gauge. Results have been obtained for several popular choices of values for the Symanzik coefficients. While our Green's function calculations regard any pointlike 4-fermion operators which do not mix with lower dimension ones, we pay particular attention to DF=2 operators, both Parity Conserving and Parity Violating (F: flavour). We compute the perturbative renormalization constants for a complete basis of 4-fermion operators and we study their mixing pattern. For some of the actions considered here, even O(a^0) results did not exis...

Constantinou, Martha; Frezzotti, Roberto; Lubicz, Vittorio; Panagopoulos, Haralambos; Skouroupathis, Apostolos; Stylianou, Fotos

2010-01-01

279

SiC MOSFET Based Single Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications  

SciTech Connect

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.

Onar, Omer C [ORNL] [ORNL; Tang, Lixin [ORNL] [ORNL; Chinthavali, Madhu Sudhan [ORNL] [ORNL; Campbell, Steven L [ORNL] [ORNL; Miller (JNJ), John M. [JNJ-Miller PLC] [JNJ-Miller PLC

2014-01-01

280

Curie temperatures and modified de Gennes factors of rare earth nitrides  

NASA Astrophysics Data System (ADS)

The Curie temperatures TC of the nitrides of the rare earths (Gd, Tb, Dy, Ho, and Er), including binary systems, were investigated. TC was found to be approximately proportional to the de Gennes factor, ?=(J(J+1), where g is the Landé g-factor and J is the total angular momentum quantum number of a trivalent rare earth (RE). This proportionality was significantly improved by introducing a modified de Gennes factor, ?. The conventional de Gennes factor ? indicates the exchange interaction given by the inner product of the effective spin components of ions of the same kind, whereas our modified de Gennes factor ? also considers interactions between different kinds of ions and statistical factors calculated on the basis of the binomial distribution. The good proportionality obtained between TC and ? indicates that the spin components of RE ions interact with each other. This interaction is considered to be responsible for the ferromagnetism of these nitrides (including binary systems). These considerations were supported by the synthesis of and magnetization measurements on Gd xEr 1- xN ( x=0, 0.25, 0.5, 0.75, 1) samples.

Hirayama, Yusuke; Nakagawa, Takashi; Yamamoto, Takao A.

2011-11-01

281

Long-Term Expression of Human Coagulation Factor VIII and Correction of Hemophilia A after in vivo Retroviral Gene Transfer in Factor VIII-Deficient Mice  

Microsoft Academic Search

Hemophilia A is caused by a deficiency in coagulation factor VIII (FVIII) and predisposes to spontaneous bleeding that can be life-threatening or lead to chronic disabilities. It is well suited for gene therapy because a moderate increase in plasma FVIII concentration has therapeutic effects. Improved retroviral vectors expressing high levels of human FVIII were pseudotyped with the vesicular stomatitis virus

Thierry Vandendriessche; Veerle Vanslembrouck; Inge Goovaerts; Hans Zwinnen; Marie-Line Vanderhaeghen; Desire Collen; Marinee K. L. Chuah

1999-01-01

282

Effect of Correcting for Long Term Variation in Major Coronary Heart Disease Risk Factors: Relative Hazard Estimation and Risk Prediction in the ARIC Study  

PubMed Central

Purpose To examine the effect of correcting coronary heart disease (CHD) risk factors for long-term within-person variation on CHD risk. Method Using 5533 men and 7301 women from the Atherosclerosis Risk in Communities (ARIC) Study, we compared models incorporating risk factors measured at a single visit and models incorporating additional measurements for systolic blood pressure, total cholesterol and high-density lipoprotein cholesterol taken 3 years prior to baseline. Results The largest change away from null was seen for systolic blood pressure: Hazard ratio (HR) 1.38 to 1.69 (+81%) in women and HR 1.26 to 1.41 (+56%) in men. Hazard ratios also decreased for age (?32% in women, ?9% in men), race (?67% in women), diabetes (?13% in men and women), and medication use for hypertension (?27% in women, ?26% in men) and cholesterol (?97% in women, HR 1.06 to 0.93 in men). The area under the ROC curve did not improve significantly in men or women, while reclassification was only significant in women (NRI 5.4%, p = 0.016). Conclusion Modeling long-term variation in CHD risk factors had a substantial impact on HR estimates, with new effect estimates further from the null for some risk factors and closer for others including age and medication use, but only improved risk classification in women. PMID:22221585

Paynter, Nina P.; Crainiceanu, Ciprian M.; Sharrett, A. Richey; Chambless, Lloyd E.; Coresh, Josef

2012-01-01

283

Network Scale-Up Correction Factors for Population Size Estimation of People Who Inject Drugs and Female Sex Workers in Iran  

PubMed Central

Introduction The results of the network scale-up (NSU) method in estimating the size of key populations for HIV might be biased if the recruited subjects are not fully informed of the risky behaviors of people in their networks (low visibility), or key populations have a smaller social network (low popularity). We aimed to measure such biases in the size estimation of people who inject drugs (PWIDs), and female sex workers (FSWs) in Iran. Methods We interviewed 163 male PWIDs, 76 FSWs (known as egos) and 600 subjects from the general population. We selected twenty first-names (ten males and ten females) and asked the study subjects separately how many people they knew with one of these names (known as alters). Visibility Factor (VF) was defined as the percentage of FSW or PWID alters that were aware of their behavior. In addition, the popularity factor (PF) was calculated by dividing the number of alters reported by FSWs and PWIDs into that of the general population. The 95% uncertainty intervals (UI) were calculated using bootstrap technique. Results The VF was estimated at 54% (95% UI: 52%–56%) for PWID and 45% (95% UI: 42%– 48%) for FSW. The VF among the peer alters was significantly higher than non-peer ones. The PF for PWID and FSW was 69% (95% UI: 66%–73%) and 77% (95% UI: 72%–83%), respectively. The cross-validation and name splitting analysis showed that our estimates were not influenced by any single name. Conclusions Both correction factors, particularly VF were far from one, and NSU results without correction, could lead to up to 4 times underestimation of the sizes. Therefore, applying these coefficients is necessary in NSU projects. PMID:25365341

Maghsoudi, Ahmad; Baneshi, Mohammad Reza; Neydavoodi, Mojtaba; Haghdoost, AliAkbar

2014-01-01

284

Factors influencing the temperature sensitivity of PMMA based optical fiber Bragg gratings  

NASA Astrophysics Data System (ADS)

The Bragg wavelength of a PMMA based fiber grating is determined by the effective core index and the grating pitch, which, in temperature sensing, depend on the thermo-optic and thermal expansion coefficients of PMMA. These two coefficients are a function of surrounding temperature and humidity. Amorphous polymers including PMMA exhibit a certain degree of anisotropic thermal expansion. The anisotropic nature of expansion mainly depends on the polymer processing history. The expansion coefficient is believed to be lower in the direction of the molecular orientation than in the direction perpendicular to the draw direction. Such anisotropic behavior of polymers can be expected in drawn PMMA based optical fiber, and will lead to a reduced thermal expansion coefficient and larger temperature sensitivity than would be the case were the fiber to be isotropic. Extensive work has been carried out to identify these factors. The temperature responses of gratings have been measured at different relative humidity. Gratings fabricated on annealed and non-annealed PMMA optical fibers are used to compare the sensitivity performance as annealing is considered to be able to mitigate the anisotropic effect in PMMA optical fiber. Furthermore an experiment has been designed to eliminate the thermal expansion contribution to the grating wavelength change, leading to increased temperature sensitivity and improved response linearity.

Zhang, Wei; Webb, David J.

2014-05-01

285

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

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 for all OF measurements. Moreover, it has been shown that these passive dosimeters do not require correction factors and can then be used as reference dosimeters. Correction factors for the active detectors have then been determined from the mean experimental OF measured by the passive dosimeters.Conclusions: Four sets of correction factors needed to apply the new small field dosimetry formalism are provided for several active detectors. A protocol for small photon beams OF determination based on passive dosimeters measurements has been recently proposed to French radiotherapy treatment centers.

Bassinet, C.; Huet, C.; Derreumaux, S.; Baumann, M.; Trompier, F.; Roch, P.; Clairand, I. [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP17, 92262 Fontenay-aux-Roses Cedex (France); Brunet, G.; Gaudaire-Josset, S. [Institut de Cancerologie de l'Ouest Rene Gauducheau, bd Jacques Monod, 44805 Saint Herblain Cedex (France); Chea, M.; Boisserie, G. [Groupe Hospitalier Pitie-Salpetriere, 47/83 bd de l'Hopital, 75651 Paris Cedex 13 (France); Lacornerie, T. [Centre Oscar Lambret, 3, rue Frederic Combemale, BP 307, 59020 Lille Cedex (France)

2013-07-15

286

ECOC comparison exercise with identical thermal protocols after temperature offsets correction - instrument diagnostics by in-depth evaluation of operational parameters  

NASA Astrophysics Data System (ADS)

A comparison exercise on thermal-optical elemental carbon/organic carbon (ECOC) analyzers was carried out among 17 European laboratories. Contrary to previous comparison exercises, the 17 participants made use of an identical instrument set-up, after correcting for temperature offsets with the application of a recently developed temperature calibration kit (Sunset Laboratory Inc, OR, US). Five filter samples and two sucrose solutions were analyzed with both the EUSAAR2 and NIOSH870 thermal protocols. z Scores were calculated for total carbon (TC) and nine outliers and three stragglers were identified. Three outliers and eight stragglers were found for EC. Overall, the participants provided results within the warning levels with the exception of two laboratories that showed poor performance, the causes of which were identified and corrected through the course of the comparison exercise. The TC repeatability and reproducibility relative standard deviations were 11.4 and 14.6% for EUSAAR2 and 9.2 and 11.7% for NIOSH870; the standard deviations for EC were 15.3 and 19.5% for EUSAAR2 and 19.9 and 25.5% for NIOSH870. TC was in good agreement between the two protocols, TCNIOSH870 = 0.98 · TCEUSAAR2 (R2 = 1.00, normalized means). Transmittance (TOT) calculated EC for NIOSH870 was found to be 20% lower than for EUSAAR2, ECNIOSH870 = 0.80 · ECEUSAAR2 (R2 = 0.96, normalized means). The thermograms and laser signal values were compared and similar peak patterns were observed per sample and protocol for most participants. Notable deviations of plotted values indicated absence or inaccurate application of the temperature calibration procedure and/or pre-oxidation during the inert phase of the analysis. Low or no pyrolytic organic carbon (POC), as reported by a few participants, is suggested as an indicator of pre-oxidation. A sample-specific pre-oxidation effect was observed for filter G, for all participants and both thermal protocols, indicating the presence of oxygen donors on the suspended particulate matter. POC (TOT) levels were lower for NIOSH870 than for EUSAAR2, which is related to the heating profile differences of the two thermal protocols.

Panteliadis, P.; Hafkenscheid, T.; Cary, B.; Diapouli, E.; Fischer, A.; Favez, O.; Quincey, P.; Viana, M.; Hitzenberger, R.; Vecchi, R.; Maggos, T.; Sciare, J.; Jaffrezo, J. L.; John, A.; Schwarz, J.; Giannoni, M.; Novak, J.; Karanasiou, A.; Fermo, P.; Maenhaut, W.

2014-08-01

287

Performance analysis and determination of the pwall correction factor for 60Co ?-ray beams for Wellhöfer Roos-type plane-parallel chambers  

NASA Astrophysics Data System (ADS)

The wall perturbation correction factor pwall in 60Co for Wellhöfer Roos-type plane-parallel ionization chambers is determined experimentally and compared with the results of a previous study using PTW-Roos chambers (Palm et al 2000 Phys. Med. Biol. 45 971-81). Five ionization chambers of the type Wellhöfer PPC-35 (or its equivalent PPC-40) are used for the analysis. Wall perturbation correction factors are obtained by assuming ND,air chamber factors determined by cross-calibration in a high-energy electron and in a 60Co ?-ray beam to be equal, and by assigning any differences to the wall perturbation factor. The procedure yields a pwall value of 1.018 (uc = 0.010), which is slightly higher than the value 1.014 (uc = 0.010) formerly obtained for the PTW-Roos chambers using the ND,air method. The chamber-to-chamber variation in pwall for the Wellhöfer-Roos chambers is found to be very small, with a maximum difference of 0.3%. The effect of using new pcav values for graphite-walled Farmer-type chambers used in water in electron beams is to decrease pwall by approximately 0.5%. The long- and short-term stability of the Roos-type chambers manufactured by Wellhöfer is investigated by measurements at the IAEA Dosimetry Laboratory in Vienna, Austria, and at the Sahlgrenska University Hospital in Göteborg, Sweden. Calibrations made at the IAEA over several months show variations in the ND,w calibration factors larger than expected, based on previous experiences with PTW-Roos chambers. Measurements of the short-term stability of the Wellhöfer-Roos chambers show a marked increase in chamber response for the time the chambers are immersed in water, pointing to a possible problem in the chamber design. As a consequence of these findings, Wellhöfer is currently working on a re-design of the chamber to solve the stability problem.

Palm, Åsa; Czap, Ladislav; Andreo, Pedro; Mattsson, Olof

2002-02-01

288

Tuberculosis outbreak in a housing unit for human immunodeficiency virus-infected patients in a correctional facility: transmission risk factors and effective outbreak control.  

PubMed

In 1995, an outbreak of tuberculosis (TB) occurred among residents of a correctional-facility housing unit for inmates infected with human immunodeficiency virus (HIV). We isolated and treated patients who were suspected to have TB. To determine risk factors for in-prison transmission of TB, we conducted a case-control study to compare inmate case patients infected with a distinct outbreak strain of TB with control subjects who resided in the HIV unit. We identified 15 case patients during a 4-month period. Among inmates with a CD4 count of <100 cells/mm(3), case patients were more likely than control subjects to spend >/=20 hours per week in a communal day room (odds ratio, 42; P=.002) and were less likely to have a television in their single-person room (odds ratio, 0.10; P=.003). The communal day room was a likely site of transmission. Successful collaboration between the correctional system and public health departments halted the outbreak. PMID:11803502

Mohle-Boetani, Janet C; Miguelino, Vanessa; Dewsnup, Daniel H; Desmond, Edward; Horowitz, Evalyn; Waterman, Stephen H; Bick, Joseph

2002-03-01

289

Two-Dimensional Thermal Boundary Layer Corrections for Convective Heat Flux Gauges  

NASA Technical Reports Server (NTRS)

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

Kandula, Max; Haddad, George

2007-01-01

290

New district-heating system economic factors vary with different supply temperatures  

SciTech Connect

District heating has been in use for many years and offers economic, environmental, and energy conservation benefits. A new district heating system may be based on either a steam or hot water distribution system. The supply media choice is based upon the composition of the load and other factors. This report discusses the relative advantages of steam vs hot water systems and between hot water systems of varying temperatures. Points of comparison include: capital costs, cogeneration efficiencies, building conversion costs, operating and maintenance costs, energy losses, maximum transport distances, and cooling applications. The major conclusion is that a thorough analysis of the market, including building equipment and consumer requirements, is essential in designing a district heating system and is of primary importance in determining the optimum supply temperature.

Borkowski, R.J.; Stovall, T.K.; Karnitz, M.A.

1982-10-01

291

Monte Carlo computed machine-specific correction factors for reference dosimetry of TomoTherapy static beam for several ion chambers  

SciTech Connect

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 (0.661), the additional correction k{sub Q{sub m{sub s{sub r{sub ,Q}{sup f{sub m}{sub s}{sub r}{sub ,}f{sub r}{sub e}{sub f}}}}}} to k{sub Q,Q{sub o}} defined in Alfonso et al. [Med. Phys. 35, 5179-5186 (2008)] formalism was in a range from 0.997 to 1.004.Conclusion: The MC computed factors in this study are in agreement with measured factors for chamber types already studied in literature. This work provides msr correction factors for additional chambers used in reference dosimetry. All of them were close to one (within 1%).

Sterpin, E.; Mackie, T. R.; Vynckier, S. [Department of Molecular Imaging, Radiation and Oncology, Universite Catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels (Belgium); Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Department of Molecular Imaging, Radiation and Oncology, Universite Catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels (Belgium)

2012-07-15

292

Polysaccharide peptide induces a tumor necrosis factor-?-dependent drop of body temperature in rats.  

PubMed

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-? (TNF-?) level. Pretreatment of the rats with anti-TNF-? 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-?-dependent. PMID:25086966

Jedrzejewski, Tomasz; Piotrowski, Jakub; Wrotek, Sylwia; Kozak, Wieslaw

2014-08-01

293

Corrections ENGINEERING  

E-print Network

�5754 CORRECTIONS #12;MEDICAL SCIENCES Correction for "Differentiated kidney epithelial cells repair injured, specifically Flow Cytometry Core. This work was supported by the National Cancer Institute Center of Cancer Nanotechnology Excellence at MIT-Harvard (U54-CA151884), the National Heart, Lung, and Blood Institute, National

Epstein, Irving R.

294

Quark-gluon plasma fireball evolution with one-loop correction in the mean-field potential  

NASA Astrophysics Data System (ADS)

The study of the free energy evolution of quark-gluon plasma (QGP) with one-loop correction factor in the mean-field potential is discussed. The energy evolution with the effect of the correction factor in potential shows a higher transition temperature in the range of T=180 to 250MeV in comparison to the transition temperature without the one-loop correction factor. The transition temperature is also affected by the dynamical flow parameter of quark and gluon used in the potential and it results in decreasing observable QGP droplets of stable radius 2.5-4.5 fm.

Singh, S. Somorendro; Ramanathan, R.

2014-10-01

295

Deep level observation in InP by temperature dependence of the van der Pauw`s symmetry factor  

SciTech Connect

One of the most convenient methods of the basic characterization of the semiconductors is the Hall effect measurement by van der Pauw`s geometry. As a by-product, the symmetry factor and a function of the symmetry factor is calculated. It is supposed that temperature dependent changes in the value of the symmetry factor indicate inhomogeneities of the sample, since this factor describes an electrical symmetry of the sample, not simply a geometrical one. Otherwise this factor is not assumed as an important information. In this work the author wishes to demonstrate that this factor can indicate quite important properties of the sample.

Somogyi, K. [Hungarian Academy of Sciences, Budapest (Hungary). Research Inst. for Technical Physics

1996-12-31

296

Estimates of rainfall over the United Kingdom and surrounding seas from the SSM/I using the polarization corrected temperature algorithm  

SciTech Connect

The 85-GHz polarization corrected temperature PCT{sub 85} algorithm, using the V85 and H85 channels of the SSM/I sensor, is evaluated for estimation of midlatitude rainfall. The algorithm {theta} parameter and rain/no-rain thresholds are examined and found to be highly variable. Methods for automatic calibration, to account for variable atmospheric and surface conditions, are presented. Derivation of {theta} and thresholds for each individual scene provides a marked improvement in rainfall identification accuracy over the equivalent monthly values. The algorithm is calibrated by comparison with radar data for the estimation of instantaneous rain rates. Detailed evaluation of a number of case studies suggest the relationship of PCT{sub 85} and rain rate is substantially different for frontal and mesoscale convective system rainfall. For most frontal conditions the PCT{sub 85} provides useful estimates of rain rates with sensitivity to rain intensities as low as 0.1 mm h{sup -1}. Overall, the PCT{sub 85} estimates of instantaneous rain rate at the footprint scale are to within {+-}75% of the radar quantity only 50% of the time. Systematic errors result from both the calibration process and from the inability of microwave scattering methods to identify warm rain processes, including orographically enhanced rainfall over land. The results show the need for improved empirical calibration of passive microwave algorithms to provide sensitivity to subsynoptic-scale surface and atmospheric conditions and rainfall processes. 25 refs., 14 figs., 5 tabs.

Todd, M.C.; Bailey, J.O. [Univ. of Bristol (United Kingdom)] [Univ. of Bristol (United Kingdom)

1995-06-01

297

Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam.  

PubMed

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

Pham, C H; Vu, C C; Sommer, S G; Bruun, S

2014-07-01

298

Somatosensory factors in taste perception: Effects of active tasting and solution temperature  

PubMed Central

Touch and temperature are recognized as important factors in food perception, but much remains to be learned about how they contribute to the perception of flavor. The present paper describes human psychophysical studies that investigated two recently discovered effects of mechanical and thermal stimulation on taste: (1) enhancement of the savory taste of MSG by active tongue and mouth movements, and (2) modulation of the rate of adaptation to sucrose sweetness by temperature. The first study provides evidence that for MSG but not other taste stimuli, movement of the tongue against the palate enhances taste intensity both by increasing spatial summation between opposing gustatory surfaces and by a hypothesized interaction with touch/kinesthesis. The second study shows that the rate of adaptation to sucrose sweetness (but not quinine bitterness) on the tongue tip is strongly influenced by temperature. It is hypothesized that warming slows adaptation to sucrose by increasing the sensitivity of an early stage of taste transduction. Together these results demonstrate that models of flavor perception must include somatosensory stimuli both as components of flavor perception and as modulators of taste. PMID:22609629

Green, Barry G.; Nachtigal, Danielle

2012-01-01

299

Dust correction factors over 0 < z < 3 in massive star-forming galaxies derived from a stacking analysis of Herschel data  

NASA Astrophysics Data System (ADS)

We use a stacking analysis in Herschel/PACS to study the accuracy of several dust-correction factors that are typically employed to estimate the total star-formation rate (SFR) of high-redshift, massive, star-forming (SF) galaxies. We also analyze what stacking suggests about the relation between SFR and stellar mass and the redshift evolution of the specific SFR (sSFR = SFR/M?). We find that the dust properties of massive SF galaxies evolve with redshift, that is, galaxies at z ~ 2-3 are more attenuated than at z ~ 1 for a given UV continuum slope and stellar mass. As a consequence, a single IRX-? or dust-mass relation cannot be used to recover the total SFR of massive SF galaxies at 0 ? z ? 3. This might have implications for studies at higher redshifts, where a single IRX-? relation derived for local starbursts is usually assumed to be valid. However, we find evidence that the local relations might be valid at least up to z ~ 1, where bluer and less massive galaxies can be detected through stacking. The spectral energy distribution fitting procedure with stellar population templates gives overestimated values (about 0.3-0.5 dex in log SFR) of the dust-corrected SFR at all redshifts studied here. We find that the slope of the main-sequence of star formation is flatter than previously found in massive galaxies with log (M?/M?) ? 10, and the redshift evolution of the sSFR reported in previous works in massive galaxies is well recovered. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendix A is available in electronic form at http://www.aanda.org

Oteo, I.

2014-12-01

300

Trends in 1970-2010 summertime coastal California air temperatures:how HCN-corrections to COOP-data eliminated coastal-cooling  

NASA Astrophysics Data System (ADS)

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 the highest COOP Tmax-values anytime (at each of its 28 sites) during the period from 1970-2010 shows three sub-areas, with a boundary-temperature of 340C (and with the following ranges): (a) cool coastal (27-340C), (b) cool mountain-tops (28-340C), and (c) in-between hot-area (34-400C). The spatial distribution of the trends in these extreme Tmax-values show decreases up to -0.80C/dec in the coastal cooling areas and increases up to 0.60C/dec in the inland and mountain warming areas. Note that these trends are larger than the monthly-averaged Tmax-trends (about ±0.30C/dec) in Lebassi et al.

Bornstein, R. D.; Ghebreegziabher, A. T.; Lebassi, B.; González, J. E.

2011-12-01

301

D.A. Stone A.J. Weaver Factors contributing to diurnal temperature range trends in twentieth  

E-print Network

model repre- senting the atmosphere, ocean, sea ice, and land surface systems. Consistent with pastD.A. Stone Ã? A.J. Weaver Factors contributing to diurnal temperature range trends in twentieth temperature range (DTR) are examined in the late twentieth and the twenty-first centuries in a coupled climate

302

Variations of karst underground air temperature induced by various factors (Cave of Županova jama, Central Slovenia)  

NASA Astrophysics Data System (ADS)

On the basis of air temperature ( T) monitoring, basic statistical and time series analysis was employed to evaluate thermal states of cave atmosphere variations. Long-term, seasonal and event comparative analysis as well as spectral and cross-correlation analysis was conducted. The results show the relative stability of air T in the isolated part of the cave, whereas variable air T was observed in the parts close to entrances and the surface. The distinctive seasonality in this part of the cave demonstrates that air convection is a driving force for the heat exchange between the cave and the surrounding environment. External air T and heat conducted through the rock walls are also an important factor influencing the cave climate, while heat released by the ice deposit and by water infiltrating through the cave ceiling has a negligible effect. Occasional irregular variations in daily patterns are caused by human impact.

Ravbar, Natasa; Kosutnik, Jure

2014-04-01

303

The factors that determine the temperature of fusion of Cu and Ni thin films on inert surfaces  

Microsoft Academic Search

A method for calculating the temperature of fusion of thin films depending on their thickness was suggested. It was shown\\u000a for the example of copper and nickel films that the main factors that determined a substantial decrease in the temperature\\u000a of fusion of thin films compared with massive materials were the different heats of fusion of thin films, the temperature

D. G. Gromov; S. A. Gavrilov; E. N. Redichev; A. V. Klimovitskaya; R. M. Ammosov

2006-01-01

304

Interactions among Factors Regulating Phenological Development and Acclimation Rate Determine Low-temperature Tolerance in Wheat  

PubMed Central

• Background and Aims Exposure to low temperatures (LT) produces innumerable changes in morphological, biochemical and physiological characteristics of plants, with the result that it has been difficult to separate cause and effect adjustments to LT. Phenotypic studies have shown that the LT-induced protective mechanisms in cereals are developmentally regulated and involve an acclimation process that can be stopped, reversed and restarted. The present study was initiated to separate the developmental factors determining duration from those responsible for rate of acclimation, to provide the opportunity for a more in depth analysis of the critical mechanisms that regulate LT tolerance in wheat (Triticum aestivum). • Methods The non-hardy spring wheat cultivar ‘Manitou’ and the very cold-hardy winter wheat cultivar ‘Norstar’ were used to produce reciprocal near-isogenic lines (NILs) in which the vrn-A1 (winter) alleles of ‘Norstar’ were inserted into the non-hardy ‘Manitou’ genetic background and the Vrn-A1 (spring) alleles of ‘Manitou’ were inserted in the hardy ‘Norstar’ genetic background so that the effects of duration and rate of LT acclimation could be quantified. • Key Results Comparison of the acclimation curves of the NILs and their parents grown at 2, 6 and 10 °C established that the full expression of LT-induced genetic systems was revealed only under genotypically dependent optimum combinations of time and temperature. Both duration and rate of acclimation were found to contribute significantly to the 13·8 °C difference in lowest survival temperature between ‘Norstar’ and ‘Manitou’. • Conclusions Duration of LT acclimation was dependent upon the rate of phenological development, which, in turn, was determined by acclimation temperatures and vernalization requirements. Rate of acclimation was faster for genotypes with the ‘Norstar’ genetic background but the ability to sustain a high rate of acclimation was dependent upon the length of the vegetative stage. Complex time/temperature relationships and unexplained genetic interactions indicated that detailed functional genomic or phenomic analyses of natural allelic variation will be required to identify the critical genetic components of a highly integrated system, which is regulated by environmentally responsive, complex pathways. PMID:15374834

FOWLER, D. B.; LIMIN, A. E.

2004-01-01

305

Assessing the correctional orientation of corrections officers in South Korea.  

PubMed

The correctional goal in South Korea has recently changed from the straightforward punishment of inmates to rehabilitation. Currently, emphases are being placed on education, counseling, and other treatment programs. These changes have consequently begun to also change the corrections officers' roles from a purely custodial role to a human service role, in which officers are expected to manage rehabilitation and treatment programs. Despite these changes, few studies have examined the attitudes of corrections officers toward rehabilitation programming. This is an important dimension to examine in rehabilitation programming, as corrections officers play a major role in the delivery of institutional programs. This study examines the attitudes of South Korean corrections officers toward rehabilitation programs. Approximately 430 corrections officers were sampled. Results show that correctional attitudes are largely influenced by not only officers' own motivations for joining corrections but also by institutional factors such as job stress. Policy implications are discussed. PMID:15538029

Moon, Byongook; Maxwell, Sheila Royo

2004-12-01

306

A regional extreme low temperature event and its main atmospheric contributing factors  

NASA Astrophysics Data System (ADS)

The regional extreme low temperature event from December 30, 2010 to February 2, 2011 was a very rare and protracted cold event with the largest integrated index ( Z) since 1979. Two meteorological factors could be responsible for this extreme winter event. First, a persistent blocking pattern existed in the mid-latitudes. This not only allowed cold air to persist in southern China but also enabled each perturbation from the west propagating around the blocking high to trigger downstream cold air intrusions from the north. Second, the consistently downward negative Arctic Oscillation (AO) was favorable for the eastward moving of Rossby waves in middle latitudes, which made the upper reaches positive center in SLP and negative center in Z500 move to East Asia. This stable and consistent situation favored the polar area cold air invasion to the mid-latitude region. Of these two factors, the blocking pattern was likely to be the direct cause, the co-effects of consistently strong downward negative AO from the stratosphere, and the corresponding eastward moving wave train in Z500 and SLP might be the prophase teleconnection culprit.

Gong, Zhiqiang; Feng, Guolin; Ren, Fumin; Li, Jianping

2014-07-01

307

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

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

Zúñiga-Mayo, Victor M; Marsch-Martínez, Nayelli; de Folter, Stefan

2012-07-01

308

Corrections to \\  

Microsoft Academic Search

In the above titled paper (ibid., vol. 23, no. 3, pp. 443-458, Jun 07), Fig. 11 was printed with some mathematical symbols missing in lines 3, 6, 8, and 13. The corrected figure and its caption are presented here.

Min Li; Yun-hui Liu

2007-01-01

309

EFFECT OF ENVIRONMENTAL FACTORS ON PHYTOPLANKTON GROWTH: TEMPERATURE AND THE INTERACTIONS OF TEMPERATURE WITH NUTRIENT LIMITATION (JOURNAL VERSION)  

EPA Science Inventory

The combined stress of nutrient limitation and suboptimal temperature on growth was studied with turbidostat and chemostat cultures of Scenedesmus sp. and Asterionella formosa. The combined effects were greater than the sum of individual effects and were not multiplicative. In N-...

310

Exposure Corrections for Macrophotography  

ERIC Educational Resources Information Center

Describes a method for determining the exposure correction factors in close-up photography and macrophotography. The method eliminates all calculations during picture-taking, and allows the use of a light meter to obtain the proper f-stop/exposure time combinations. (Author/MLH)

Nikolic, N. M.

1976-01-01

311

Heat shock factor is required for growth at normal temperatures in the fission yeast Schizosaccharomyces pombe.  

PubMed Central

Schizosaccharomyces pombe is becoming an increasingly useful organism for the study of cellular processes, since in certain respects, such as the cell cycle and splicing, it is similar to metazoans. Previous biochemical studies have shown that the DNA binding ability of S. pombe heat shock factor (HSF) is fully induced only under stressed conditions, in a manner similar to that of Drosophila melanogaster and humans but differing from the constitutive binding by HSF in the budding yeasts. We report the isolation of the cDNA and gene for the HSF from S. pombe. S. pombe HSF has a domain structure that is more closely related to the structure of human and D. melanogaster HSFs than to the structure of the budding yeast HSFs, further arguing that regulation of HSF in S. pombe is likely to reflect regulation in metazoans. Surprisingly, the S. pombe HSF gene is required for growth at normal temperatures. We show that the S. pombe HSF gene can be replaced by the D. melanogaster HSF gene and that strains containing either of these genes behave similarly to transiently heat-shocked strains with respect to viability and the level of heat-induced transcripts from heat shock promoters. Strains containing the D. melanogaster HSF gene, however, have lower growth rates and show altered morphology at normal growth temperatures. These data demonstrate the functional conservation of domains of HSF that are required for response to heat shock. They further suggest a general role for HSF in growth of eukaryotic cells under normal (nonstressed) growth conditions. Images PMID:8423799

Gallo, G J; Prentice, H; Kingston, R E

1993-01-01

312

A Monte Carlo method to evaluate the impact of positioning errors on detector response and quality correction factors in nonstandard beams  

NASA Astrophysics Data System (ADS)

During experimental procedures, an adequate evaluation of all sources of uncertainty is necessary to obtain an overall uncertainty budget. In specific radiation dosimetry applications where a single detector is used, common methods to evaluate uncertainties caused by setup positioning errors are not applicable when the dose gradient is not known a priori. This study describes a method to compute these uncertainties using the Monte Carlo method. A mathematical formalism is developed to calculate unbiased estimates of the uncertainties. The method is implemented in egs_chamber, an EGSnrc-based code that allows for the efficient calculation of detector doses and dose ratios. The correct implementation of the method into the egs_chamber code is validated with an extensive series of tests. The accuracy of the developed mathematical formalism is verified by comparing egs_chamber simulation results to the theoretical expectation in an ideal situation where the uncertainty can be computed analytically. Three examples of uncertainties are considered for realistic models of an Exradin A12 ionization chamber and a PTW 60012 diode, and results are computed for parameters representing nearly realistic positioning error probability distributions. Results of practical examples show that uncertainties caused by positioning errors can be significant during IMRT reference dosimetry as well as small field output factor measurements. The method described in this paper is of interest in the study of single-detector response uncertainties during nonstandard beam measurements, both in the scope of daily routine as well as when developing new dosimetry protocols. It is pointed out that such uncertainties should be considered in new protocols devoted to single-detector measurements in regions with unpredictable dose gradients. The method is available within the egs_chamber code in the latest official release of the EGSnrc system.

Bouchard, Hugo; Seuntjens, Jan; Kawrakow, Iwan

2011-04-01

313

A Monte Carlo method to evaluate the impact of positioning errors on detector response and quality correction factors in nonstandard beams.  

PubMed

During experimental procedures, an adequate evaluation of all sources of uncertainty is necessary to obtain an overall uncertainty budget. In specific radiation dosimetry applications where a single detector is used, common methods to evaluate uncertainties caused by setup positioning errors are not applicable when the dose gradient is not known a priori. This study describes a method to compute these uncertainties using the Monte Carlo method. A mathematical formalism is developed to calculate unbiased estimates of the uncertainties. The method is implemented in egs_chamber, an EGSnrc-based code that allows for the efficient calculation of detector doses and dose ratios. The correct implementation of the method into the egs_chamber code is validated with an extensive series of tests. The accuracy of the developed mathematical formalism is verified by comparing egs_chamber simulation results to the theoretical expectation in an ideal situation where the uncertainty can be computed analytically. Three examples of uncertainties are considered for realistic models of an Exradin A12 ionization chamber and a PTW 60012 diode, and results are computed for parameters representing nearly realistic positioning error probability distributions. Results of practical examples show that uncertainties caused by positioning errors can be significant during IMRT reference dosimetry as well as small field output factor measurements. The method described in this paper is of interest in the study of single-detector response uncertainties during nonstandard beam measurements, both in the scope of daily routine as well as when developing new dosimetry protocols. It is pointed out that such uncertainties should be considered in new protocols devoted to single-detector measurements in regions with unpredictable dose gradients. The method is available within the egs_chamber code in the latest official release of the EGSnrc system. PMID:21454927

Bouchard, Hugo; Seuntjens, Jan; Kawrakow, Iwan

2011-04-21

314

Assessment of climatic factors influence on interannual changes in the global surface air temperature  

NASA Astrophysics Data System (ADS)

A model to assess a number of factors such as TSI, albedo, cloudiness and greenhouse gases including water vapour affecting global surface air temperature (SAT) changes has been developed. To develop the model solar energy transformation in the atmosphere and the other radiation fluxes transformation were investigated. It's a common knowledge that some part of the incoming solar energy is reflected into space by the Earth's surface, aerosol and cloud particles. A contribution of these components to changes in the reflected solar energy was assessed on the basis of developed linear parameterization. During the period of 2001 - 2010, clouds were found to be the basic contributor to the changes in reflected shortwave radiation. Some part of outgoing terrestrial radiation is retained in the atmosphere by greenhouse gases, water vapour and cloudiness. A contribution of these components to changes in the absorbed longwave radiation was assessed on the basis of developed linear parameterization. It was estimated that the contribution of water vapour was dominant during the analyzed period. The developed parameterization of global albedo made it possible to assess the contribution of TSI to global SAT changes. Making use of the parameterizations listed above the model has been improved. The model calculations showed that the our projections of global SAT to 2030 were lower than IPCC estimates.

Gusakova, Maria; Karlin, Lev

2014-05-01

315

Improving source identification of Atlanta aerosol using temperature resolved carbon fractions in positive matrix factorization  

NASA Astrophysics Data System (ADS)

Daily integrated PM 2.5 (particulate matter ?2.5 ?m in aerodynamic diameter) composition data including eight individual carbon fractions collected at the Jefferson Street monitoring site in Atlanta were analyzed with positive matrix factorization (PMF). Particulate carbon was analyzed using the thermal optical reflectance method that divides carbon into four organic carbon (OC), pyrolized organic carbon (OP), and three elemental carbon (EC) fractions. A total of 529 samples and 28 variables were measured between August 1998 and August 2000. PMF identified 11 sources in this study: sulfate-rich secondary aerosol I (50%), on-road diesel emissions (11%), nitrate-rich secondary aerosol (9%), wood smoke (7%), gasoline vehicle (6%), sulfate-rich secondary aerosol II (6%), metal processing (3%), airborne soil (3%), railroad traffic (3%), cement kiln/carbon-rich (2%), and bus maintenance facility/highway traffic (2%). Differences from previous studies using only the traditional OC and EC data (J. Air Waste Manag. Assoc. 53(2003a)731; Atmos Environ. (2003b)) include four traffic-related combustion sources (gasoline vehicle, on-road diesel, railroad, and bus maintenance facility) containing carbon fractions whose abundances were different between the various sources. This study indicates that the temperature resolved fractional carbon data can be utilized to enhance source apportionment study, especially with respect to the separation of diesel emissions from gasoline vehicle sources. Conditional probability functions using surface wind data and identified source contributions aid the identifications of local point sources.

Kim, Eugene; Hopke, Philip K.; Edgerton, Eric S.

316

Factoring  

NSDL National Science Digital Library

Test your factoring skills Factors and Multiples Jeopardy How much do you know about factoring and multiples? Play Jeopardy and find out! Prime Factoring Turkey Shoot Blast these turkeys using your factoring skills. Help the Professor Super save the planet by "cooking" the Giant Frozen Turkeys of Destruction. Math Lines 12 X-Factor Shoot the ball at the other factors to get a product of 12. You can also ...

Clark, Mr

2012-10-31

317

Genotype-specific risk factors for Staphylococcus aureus in Swiss dairy herds with an elevated yield-corrected herd somatic cell count.  

PubMed

Bovine mastitis is a frequent problem in Swiss dairy herds. One of the main pathogens causing significant economic loss is Staphylococcus aureus. Various Staph. aureus genotypes with different biological properties have been described. Genotype B (GTB) of Staph. aureus was identified as the most contagious and one of the most prevalent strains in Switzerland. The aim of this study was to identify risk factors associated with the herd-level presence of Staph. aureus GTB and Staph. aureus non-GTB in Swiss dairy herds with an elevated yield-corrected herd somatic cell count (YCHSCC). One hundred dairy herds with a mean YCHSCC between 200,000 and 300,000cells/mL in 2010 were recruited and each farm was visited once during milking. A standardized protocol investigating demography, mastitis management, cow husbandry, milking system, and milking routine was completed during the visit. A bulk tank milk (BTM) sample was analyzed by real-time PCR for the presence of Staph. aureus GTB to classify the herds into 2 groups: Staph. aureus GTB-positive and Staph. aureus GTB-negative. Moreover, quarter milk samples were aseptically collected for bacteriological culture from cows with a somatic cell count ?150,000cells/mL on the last test-day before the visit. The culture results allowed us to allocate the Staph. aureus GTB-negative farms to Staph. aureus non-GTB and Staph. aureus-free groups. Multivariable multinomial logistic regression models were built to identify risk factors associated with the herd-level presence of Staph. aureus GTB and Staph. aureus non-GTB. The prevalence of Staph. aureus GTB herds was 16% (n=16), whereas that of Staph. aureus non-GTB herds was 38% (n=38). Herds that sent lactating cows to seasonal communal pastures had significantly higher odds of being infected with Staph. aureus GTB (odds ratio: 10.2, 95% CI: 1.9-56.6), compared with herds without communal pasturing. Herds that purchased heifers had significantly higher odds of being infected with Staph. aureus GTB (rather than Staph. aureus non-GTB) compared with herds without purchase of heifers. Furthermore, herds that did not use udder ointment as supportive therapy for acute mastitis had significantly higher odds of being infected with Staph. aureus GTB (odds ratio: 8.5, 95% CI: 1.6-58.4) or Staph. aureus non-GTB (odds ratio: 6.1, 95% CI: 1.3-27.8) than herds that used udder ointment occasionally or regularly. Herds in which the milker performed unrelated activities during milking had significantly higher odds of being infected with Staph. aureus GTB (rather than Staph. aureus non-GTB) compared with herds in which the milker did not perform unrelated activities at milking. Awareness of 4 potential risk factors identified in this study guides implementation of intervention strategies to improve udder health in both Staph. aureus GTB and Staph. aureus non-GTB herds. PMID:24881801

Berchtold, B; Bodmer, M; van den Borne, B H P; Reist, M; Graber, H U; Steiner, A; Boss, R; Wohlfender, F

2014-08-01

318

Influence of sky view factor on outdoor thermal environment and physiological equivalent temperature  

NASA Astrophysics Data System (ADS)

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.

He, Xiaodong; Miao, Shiguang; Shen, Shuanghe; Li, Ju; Zhang, Benzhi; Zhang, Ziyue; Chen, Xiujie

2014-05-01

319

Bias correction of monthly precipitation and temperature fields from Intergovernmental Panel on Climate Change AR4 models using equidistant quantile matching  

Microsoft Academic Search

A new quantile-based mapping method is developed for the bias correction of monthly global circulation model outputs. Compared to the widely used quantile-based matching method that assumes stationarity and only uses the cumulative distribution functions (CDFs) of the model and observations for the baseline period, the proposed method incorporates and adjusts the model CDF for the projection period on the

Haibin Li; Justin Sheffield; Eric F. Wood

2010-01-01

320

Aureolegraph internal scattering correction.  

PubMed

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

DeVore, John; Villanucci, Dennis; LePage, Andrew

2012-11-20

321

The Retrieval of Ice Water Content from Radar Reflectivity Factor and Temperature and Its Use in Evaluating a Mesoscale Model  

E-print Network

The Retrieval of Ice Water Content from Radar Reflectivity Factor and Temperature and Its Use form 11 June 2005) ABSTRACT Ice clouds are an important yet largely unvalidated component of weather, demonstrating that, for stratiform midlatitude ice clouds, radar reflectivity in the Rayleigh-scattering regime

Hogan, Robin

322

Is exposure temperature a confounding factor for the assessment of reproductive parameters of New Zealand mudsnails Potamopyrgus antipodarum (Gray)?  

Microsoft Academic Search

Potamopyrgus antipodarum is a promising test organism often used in ecotoxicology testing, both in laboratory and in field exposure experiments. It has been recommended for use in the development of an OECD reproduction test. However, exposure temperature is important to take into account when assessing reproduction and related biomarkers, because it can act as a confounding factor inducing variability in

M. Gust; T. Buronfosse; C. André; R. Mons; F. Gagné; J. Garric

2011-01-01

323

An improved temperature index model for alpine glaciers using derived degree-day factors from climatic inputs  

NASA Astrophysics Data System (ADS)

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.

Keeler, D. G.; Havens, A. P.; Rupper, S.; Christensen, W. F.

2013-12-01

324

Is exposure temperature a confounding factor for the assessment of reproductive parameters of New Zealand mudsnails Potamopyrgus antipodarum (Gray)?  

PubMed

Potamopyrgus antipodarum is a promising test organism often used in ecotoxicology testing, both in laboratory and in field exposure experiments. It has been recommended for use in the development of an OECD reproduction test. However, exposure temperature is important to take into account when assessing reproduction and related biomarkers, because it can act as a confounding factor inducing variability in physiological values. The effect of three environmentally realistic exposure temperatures (8, 16 and 24°C) was examined with respect to the number of neonates born, the number of embryos in the brood pouch and the duration of embryonic development. We also measured additional markers likely to be related to the modulation of reproductive performance, such as vertebrate-like sex steroid, energy status and vitellin-like proteins. Exposure temperature had a significant effect on reproduction in P. antipodarum, on both the duration of embryonic development and the quantity of embryos and neonates. The consequences of these observations must not be neglected when using this species in laboratory and field experiments. This study determined suitable temperatures for field experiments and a mean duration for embryonic development independent of temperature. In addition to steroid levels, energy status and Vn-like protein levels were only slightly modified by exposure temperature between 8 and 24°C. Thus, they can be easily implemented and their variations related to anthropogenic factors during field exposure of mudsnails. PMID:21216350

Gust, M; Buronfosse, T; André, C; Mons, R; Gagné, F; Garric, J

2011-01-25

325

Research on some influence factors in high temperature measurement of metal with thermal infrared imager  

NASA Astrophysics Data System (ADS)

Thermal infrared imagers have been introduced into the research field of metal processing temperature in recent years, such as the workpiece's and the tool's temperatures in metal machining. However, these metal components are usually non-black body with unknown and varied surface emissivities, plus the in-line processing environment also effects the measurement of infrared imager. Hereby, accurately measuring metal processing temperature with infrared imager becomes a challenge. In this paper, the temperature measurement formula of infrared imager is analyzed first, and next the experimental devices designed by the authors is introduced, then several influences on the temperature measurement, such as low temperature and high temperature backgrounds with high emissivity, object area / viewing field ratio, and the shooting angel, are experimentally investigated with a thermal infrared imager. The results indicate that a low temperature background with high emissivity and a small object area / viewing field ratio, as well as a shooting direction perpendicular to the measured surface, can improve the measurement accuracy. This work provides a useful reference for the temperature measurement in metal processing.

Yanming, QUAN; Hao, XU; Zhiyong, KE

326

Influence of some psychological factors on temperature dynamics of human hands  

NASA Astrophysics Data System (ADS)

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.

Koreneva, L. G.; Apenisheva, N. P.; Zakharov, Pavel V.; Markov, A. G.

1993-11-01

327

Anomalous variation of the Lamb-Mössbauer factor at the magnetic transition temperature in magnetoelectric GaFeO3.  

PubMed

Temperature-dependent (57)Fe Mössbauer spectroscopy (5-723 K) and neutron diffraction (2-290 K) measurements are carried out on polycrystalline magnetoelectric GaFeO(3). From the neutron diffraction data, evidence for the magnetostriction and increased disorder at Fe sites close to the ferrimagnetic Curie transition temperature (T(C)) is observed. From the Mössbauer data, it is observed that the Lamb-Mössbauer factor as a function of temperature f(T), which is related to the integral over the first Brillouin zone of the phonon spectrum, shows a unequivocal variation at the T(C). The observations are discussed in terms of spin-phonon coupling. The observed average hyperfine fields from (57)Fe Mössbauer spectra match with the bulk magnetization data. A critical exponent (?) of 0.38 ± 0.02 and a Debye temperature (?(D)) of ~350 K is estimated from the (57)Fe Mössbauer data. PMID:22914201

Sharma, Kavita; Reddy, V Raghavendra; Gupta, Ajay; Kaushik, S D; Siruguri, V

2012-09-19

328

Anomalous variation of the Lamb-Mössbauer factor at the magnetic transition temperature in magnetoelectric GaFeO3  

NASA Astrophysics Data System (ADS)

Temperature-dependent 57Fe Mössbauer spectroscopy (5-723 K) and neutron diffraction (2-290 K) measurements are carried out on polycrystalline magnetoelectric GaFeO3. From the neutron diffraction data, evidence for the magnetostriction and increased disorder at Fe sites close to the ferrimagnetic Curie transition temperature (TC) is observed. From the Mössbauer data, it is observed that the Lamb-Mössbauer factor as a function of temperature f(T), which is related to the integral over the first Brillouin zone of the phonon spectrum, shows a unequivocal variation at the TC. The observations are discussed in terms of spin-phonon coupling. The observed average hyperfine fields from 57Fe Mössbauer spectra match with the bulk magnetization data. A critical exponent (?) of 0.38 ± 0.02 and a Debye temperature (?D) of ˜350 K is estimated from the 57Fe Mössbauer data.

Sharma, Kavita; Raghavendra Reddy, V.; Gupta, Ajay; Kaushik, S. D.; Siruguri, V.

2012-09-01

329

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...

330

A hypothesis about factors that affect maximum stream temperatures across montane landscapes  

USGS Publications Warehouse

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.

Isaak, D.J.; Hubert, W.A.

2001-01-01

331

Atmospheric corrections for TIMS estimated emittance  

NASA Technical Reports Server (NTRS)

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 different from applying no corrections at all. As expected, with increasing elevation atmospheric effects are slightly reduced, because moisture tends to be concentrated in the lowermost part of the atmosphere. The black body adjustment is highly robust, and even at elevations nearly 600 meters above the sea, remains an alternative procedure for use in calculating emittance.

Warner, T. A.; Levandowski, D. W.

1992-01-01

332

Effect of design factors on surface temperature and wear in disk brakes  

NASA Technical Reports Server (NTRS)

The temperatures, friction, wear and contact conditions that occur in high energy disk brakes are studied. Surface and near surface temperatures were monitored at various locations in a caliper disk brake during drag type testing, with friction coefficient and wear rates also being determined. The recorded transient temperature distributions in the friction pads and infrared photographs of the rotor disk surface both showed that contact at the friction surface was not uniform, with contact areas constantly shifting due to nonuniform thermal expansion and wear. The effect of external cooling and of design modifications on friction, wear and temperatures was also investigated. It was found that significant decreases in surface temperature and in wear rate can be achieved without a reduction in friction either by slotting the contacting face of the brake pad or by modifying the design of the pad support to improve pad compliance. Both design changes result in more uniform contact conditions on the friction surface.

Santini, J. J.; Kennedy, F. E.; Ling, F. F.

1976-01-01

333

Dominant factors affecting temperature rise in simulations of human thermoregulation during RF exposure  

NASA Astrophysics Data System (ADS)

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.

Laakso, Ilkka; Hirata, Akimasa

2011-12-01

334

Temperature dependence and anharmonicity of the Debye-Waller factor in sodium metal using Moessbauer. gamma. -ray diffraction  

SciTech Connect

The Debye-Waller factor of sodium has been measured as a function of temperature from 80 to 295 K using Moessbauer ..gamma..-ray scattering. The high energy resolution provided by this technique allowed experimental separation of the elastic scattering from the inelastic thermal diffuse scattering. The results were compared with the harmonic model using integrations over dispersion curves from the neutron-scattering measurements of Woods et al. and the lattice-dynamics calculations of Glyde and Taylor. The Debye-Waller exponent was shown to exceed the harmonic prediction by 23% at room temperature. This difference is attributed to anharmonic terms in the interatomic potential.

Crow, M.L.; Schupp, G.; Yelon, W.B.; Mullen, J.G.; Djedid, A.

1989-01-15

335

Effect of high temperature on Pseudomonas putida NBRI0987 biofilm formation and expression of stress sigma factor RpoS.  

PubMed

Pseudomonas is an efficient plant growth-promoting rhizobacteria; however, among the limiting factors for its commercialization, tolerance for high temperature is the most critical one. After screening 2,500 Pseudomnas sp. strains, a high temperature tolerant-strain Pseudomonas putida NBRI0987 was isolated from the drought-exposed rhizosphere of chickpea (Cicer arietinum L. cv. Radhey), which was grown under rain-fed conditions. P. putida NBRI0987 tolerated a temperature of 40 degrees C for < or = 5 days. To the best of our knowledge, this is the first report of a Pseudomnas sp. demonstrating survival estimated by counting viable cells under such a high temperature. P. putida NBRI0987 colony-forming unit (CFU)/ml on day 10 in both the absence and presence of MgSO4 x 7H2O (MgSO4) in combination with glycerol at 40 degrees C were 0.0 and 1.7 x 10(11), respectively. MgSO4 plus glycerol also enhanced the ability of P. putida NBRI0987 to tolerate high temperatures by inducing its ability to form biofilm. However, production of alginate was not critical for biofilm formation. The present study demonstrates overexpression of stress sigma factor sigma(S) (RpoS) when P. putida NBRI0987 is grown under high-temperature stress at 40 degrees C compared with 30 degrees C. We present evidence, albeit indirect, that the adaptation of P. putida NBRI0987 to high temperatures is a complex multilevel regulatory process in which many different genes can be involved. PMID:18219523

Srivastava, S; Yadav, A; Seem, K; Mishra, S; Chaudhary, V; Nautiyal, C S

2008-05-01

336

Regression analysis of the relationship of the thermal diffusivity of refractory concretes to temperature and technical factors  

SciTech Connect

Multiple regression equations of the relationship of the thermal diffusivity of refractory concretes to temperature and technical factors convenient for practical use in calculations and the design of thermal equipment were obtained. Experimental data for quartz-clay and dinas concretes were used. In addition to the temperature the specific parameters investigated for quartz-clay concretes were the apparent density and the weight percentages of aluminophosphate binder and clay; for dinas concretes, the weight percentages of sodium silicofluoride, water glass, and finely ground quartzite were used. An analysis was made of the pair correlation of thermal diffusivity with the technical factors making it possible to predict the thermophysical properties of the refractory concretes in the production stage.

Tsibin, I.P.; Kuznetsov, A.T.

1988-09-01

337

Expression of Clostridium difficile Toxins A and B and Their Sigma Factor TcdD Is Controlled by Temperature  

PubMed Central

Growth temperature was found to control the expression of toxins A and B in Clostridium difficile VPI 10463, with a maximum at 37°C and low levels at 22 and 42°C in both peptone yeast (PY) and defined media. The up-regulation of toxin A and B mRNA and protein levels upon temperature upshift from 22 to 37°C followed the same kinetics, showing that temperature control occurred at the level of transcription. Experiments with Clostridium perfringens using gusA as a reporter gene demonstrated that both toxin gene promoters were temperature controlled and that their high activity at 37°C was dependent on the alternative sigma factor TcdD. Furthermore, tcdD was found to be autoinduced at 37°C. Glucose down-regulated all these responses in the C. perfringens constructs, similar to its impact on toxin production in C. difficile PY broth cultures. C. difficile proteins induced at 37°C and thus coregulated with the toxins by temperature were demonstrated by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and identified as enzymes involved in butyric acid production and as electron carriers in oxidation-reduction reactions. The regulation of toxin production in C. difficile by temperature is a novel finding apparently reflecting an adaptation of the expression of its virulence to mammalian hosts. PMID:12654792

Karlsson, Sture; Dupuy, Bruno; Mukherjee, Kakoli; Norin, Elisabeth; Burman, Lars G.; Akerlund, Thomas

2003-01-01

338

Perturbative renormalization factors and O(a2) corrections for lattice four-fermion operators with improved fermion\\/gluon actions  

Microsoft Academic Search

In this work we calculate the corrections to the amputated Green's functions of four-fermion operators, in 1-loop lattice perturbation theory. One of the novel aspects of our calculations is that they are carried out to second order in the lattice spacing, O(a2). We employ the Wilson\\/clover action for massless fermions (also applicable for the twisted mass action in the chiral

Martha Constantinou; Petros Dimopoulos; Roberto Frezzotti; Vittorio Lubicz; Haralambos Panagopoulos; Apostolos Skouroupathis; Fotos Stylianou

2011-01-01

339

Ambient temperature: a factor affecting performance and physiological response of broiler chickens  

NASA Astrophysics Data System (ADS)

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.

Donkoh, A.

1989-12-01

340

Effect factors of temperature measurements by femtosecond time-resolved CARS  

NASA Astrophysics Data System (ADS)

Femtosecond time-resolved coherent anti-Stokes Raman spectroscopy is utilized to measure the premixed methane/oxygen/nitrogen flame temperature at atmospheric-pressure. The procedure for fitting theoretical spectra to experimental spectra is explained. The experimental results show good agreements with theoretical ones and present a good repeatability. Laser parameters are very important for accurate temperature measurements. The effects of laser parameters on temperature measurements are discussed. Laser parameters in our discussion are shown as follows. Laser pulse shape is hyperbolic secant and Lorentz, respectively. The delay time between the pump and Stokes is from -40 fs to +40 fs. The central wavelength of the pump/probe pulses is from 650 nm to 700 nm. Pulse duration is from 40 fs to 120 fs. In 2000 K, variations of delay time between the pump and Stokes pulses lead to less than 5% error and while variations of the other three parameters lead to less than 1.5% error. Timing jitter is added to the pump/probe pulses and Stokes pulses. In 2000 K, the results indicate that timing jitter of 10% lead to less than 2% error for temperature measurements. In the higher temperature measurement, the impact of laser parameters' error is greater.

Zhao, Yang; Zhang, Sheng; Zhang, Zhibin; Dong, Zhiwei; Chen, Deying; Zhang, Zhonghua; Xia, Yuanqin

2014-05-01

341

Energy factors and temperature distribution in insulated built-up roofs. Technical note July 1977-January 1980  

SciTech Connect

Surface temperatures of 4-ply built-up roofs insulated with (1) 1 inch of perlite (R = 2.8) and 2-1/2 inches of urethane (R = 19.2) and (2) 1 inch of urethane (R = 7.1) and 1-7/8 inches of glass fiber (R = 7.7) are presented. Energy factors are shown in terms of temperature-time areas defined as solar heat response, cooling (heating) required, radiative cooling, and insulation efficiency. Results indicate that for a black surface, solar heat response is significantly higher in the roof portion with the higher R-value. Solar heat response is directly affected by color of surfacing; lowest to highest values were found with white, white gravel, gray gravel, aluminum-gray, and black. Recommendations are given for reducing surface temperatures of insulated built-up roofs.

Keeton, J.R.; Alumbaugh, R.L.

1981-02-01

342

Role of Hot Water System Design on Factors Influential to Pathogen Regrowth: Temperature, Chlorine Residual, Hydrogen Evolution, and Sediment  

PubMed Central

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

Brazeau, Randi H.; Edwards, Marc A.

2013-01-01

343

Effect of temperature on stability and activity of elongation factor 2 proteins from Antarctic and thermophilic methanogens.  

PubMed

Despite the presence and abundance of archaea in low-temperature environments, little information is available regarding their physiological and biochemical properties. In order to investigate the adaptation of archaeal proteins to low temperatures, we purified and characterized the elongation factor 2 (EF-2) protein from the Antarctic methanogen Methanococcoides burtonii, which was expressed in Escherichia coli, and compared it to the recombinant EF-2 protein from a phylogenetically related thermophile, Methanosarcina thermophila. Using differential scanning calorimetry to assess protein stability and enzyme assays for the intrinsic GTPase activity, we identified biochemical and biophysical properties that are characteristic of the cold-adapted protein. This includes a higher activity at low temperatures caused by a decrease of the activation energy necessary for GTP hydrolysis and a decreased activation energy for the irreversible denaturation of the protein, which indicates a less thermostable structure. Comparison of the in vitro properties of the proteins with the temperature-dependent characteristics of growth of the organisms indicates that additional cytoplasmic factors are likely to be important for the complete thermal adaptation of the proteins in vivo. This is the first study to address thermal adaptation of proteins from a free-living, cold-adapted archaeon, and our results indicate that the ability of the Antarctic methanogen to adapt to the cold is likely to involve protein structural changes. PMID:10671454

Thomas, T; Cavicchioli, R

2000-03-01

344

Uncovering Different Masking Factors on Wrist Skin Temperature Rhythm in Free-Living Subjects  

PubMed Central

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

Martinez-Nicolas, Antonio; Ortiz-Tudela, Elisabet; Rol, Maria Angeles; Madrid, Juan Antonio

2013-01-01

345

Alternate corrections for estimating actual wetland evapotranspiration from potential evapotranspiration  

USGS Publications Warehouse

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.

Barclay, Shoemaker W.; Sumner, D.M.

2006-01-01

346

The Spatial Variations of Urban Land Surface Temperatures: Pertinent Factors, Zoning Effect, and Seasonal Variability  

Microsoft Academic Search

Remote sensing of urban land surface temperatures (LSTs) has been conducted based largely on pixel-by-pixel correlation with land use and land cover (LULC) types. Few studies have examined the spatial variations of LST within land use zoning polygons, in spite of its significance on the knowledge of environmental implications or planning practices. This study aimed to analyze the spatial patterns

Qihao Weng; Hua Liu; Bingqing Liang; Dengsheng Lu

2008-01-01

347

Physicochemical Factors Affecting Toxicity in Freshwater: Hardness, pH, and Temperature (Chapter 1).  

National Technical Information Service (NTIS)

A search of the literature for effects of hardness, pH, or temperature on the toxicity of chemicals to freshwater organisms suggested that the amount of reliable and useful data is limited. Much of the disparity among results reported in the literature wa...

F. L. Mayer, L. L. Marking, T. D. Bills, G. E. Howe

1994-01-01

348

Calibration factor of track etch detectors at different temperatures of water  

E-print Network

Research was performed to determine track density as a function of radon exposure in water and exposure temperature for the track etch detectors Kodak LR II 5 Type 2 and CR-39. Films were submerged in water containing a known concentration...

Yasmeen, Nuzhat

2012-06-07

349

Ambient temperature: a factor affecting performance and physiological response of broiler chickens  

Microsoft Academic Search

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°,

A. Donkoh

1989-01-01

350

High Temperature Requirement Factor A1 (HTRA1) Gene Regulates Angiogenesis through Transforming Growth  

E-print Network

requirement factor A1 (HTRA1) gene associated with age-re- lated macular degeneration (AMD). As a secreted, we identified a single nucleotide polymorphism (SNP) rs6982567 A/G near the GDF6 gene in the RPE layer, retinal and brain tissues in HTRA1 knock-out (htra1 / ) mice as com- pared with the wild

351

Factors affecting cycle life in ambient temperature of secondary lithium batteries  

NASA Technical Reports Server (NTRS)

Three major factors are discussed: electrode integrity, electrolyte stability, and dendrite formation. It is concluded that elastomers can function as improved binders for rechargeable cathodes. The cathodes can retain integrity under long cycle life with no visual deteriorations. It is found that microelectrodes can be made from powdery cathode materials for voltammetry studies.

Somoano, R.

1982-01-01

352

Developmental Expression of Steroidogenic Factor 1 in a Turtle with Temperature-Dependent Sex Determination  

E-print Network

tissues of the red-eared slider turtle (Trachemys scripta), a TSD species, detected a single primary SF-1 Key Words: steroidogenic factor 1, SF-1; Ad4BP; FTZ-F1; reptile; turtle; Trachemys scripta-eared slider turtle (Trachemys scripta), only males are pro- duced when eggs are incubated at 26°C, and only

Crews, David

353

Oxidative stress as a necessary factor in room temperature- induced apoptosis of HL60 cells  

Microsoft Academic Search

HL-60 cells undergo apoptosis when placed at room temperature (RT) (Shimura et al. (1997) FEBS Lett. 417, 379-384). We report that superoxide anion radical, one of the reactive oxygen species (ROS), was produced after RT treatment. Affinity blot analysis with a biotinylated YVAD-CHO detected the generation of processed peptides with molecular masses of 15-25 kDa. Ac- tivation of such an

Mari Shimura; Yutaka Osawa; Akira Yuo; Kiyohiko Hatake; Fumimaro Takaku; Yukihito Ishizaka

2000-01-01

354

Neutron multipilication factors as a function of temperature: a comparison of calculated and measured values for lattices using ²³³UOâ-ThOâ fuel in graphite  

Microsoft Academic Search

Neutron multiplication factors calculated as a function of temperature for three graphite-moderated ²³³UOâ-ThOâ-fueled lattices are correlated with the values measured for these lattices in the high-temperature lattice test reactor (HTLTR). The correlation analysis is accomplished by fitting calculated values of k\\/sub infinity\\/(T) to the measured values using two least-squares-fitted correlation coefficients: (a) a normalization factor and (b) a temperature coefficient

D. F. Newman; B. F. Gore

1978-01-01

355

Quantum field theory of dilute homogeneous Bose-Fermi mixtures at zero temperature: General formalism and beyond mean-field corrections  

Microsoft Academic Search

We consider a dilute homogeneous mixture of bosons and spin-polarized\\u000afermions at zero temperature. We first construct the formal scheme for carrying\\u000aout systematic perturbation theory in terms of single particle Green's\\u000afunctions. We introduce a new relevant object, the renormalized boson-fermion\\u000aT-matrix which we determine to second order in the boson-fermion s-wave\\u000ascattering length. We also discuss how to

Alexander P. Albus; Simon A. Gardiner; Fabrizio Illuminati; Martin Wilkens

2002-01-01

356

Improving source identification of Atlanta aerosol using temperature resolved carbon fractions in positive matrix factorization  

Microsoft Academic Search

Daily integrated PM2.5 (particulate matter ?2.5?m in aerodynamic diameter) composition data including eight individual carbon fractions collected at the Jefferson Street monitoring site in Atlanta were analyzed with positive matrix factorization (PMF). Particulate carbon was analyzed using the thermal optical reflectance method that divides carbon into four organic carbon (OC), pyrolized organic carbon (OP), and three elemental carbon (EC) fractions.

Eugene Kim; Philip K. Hopke; Eric S. Edgerton

2004-01-01

357

Intrinsic factors involved in the depression of neuronal activity induced by temperature increase in rat hippocampal neurons.  

PubMed

The intrinsic factors involved in the temperature-dependent impairment of neuronal activity in hippocampal CA2-CA1 regions were investigated using optical recording techniques. At 32 degrees C, stimulation of the Schaffer collaterals in the hippocampal CA2 region evoked depolarizing optical responses that spread toward the CA1 region. The optical response was characterized by fast and slow components that were mainly related to the presynaptic action potentials and excitatory postsynaptic response, respectively. The increase of the temperature to 38 degrees C was associated with a reversible depression of the neuronal activity in the hippocampal brain preparations. The depression of neuronal activity was irreversible when the temperature was increased to 40 degrees C. In the presence of 22 mM glucose, the depression of the neuronal activity at 38 degrees C was significantly attenuated. Pyruvate (22 mM), but not lactate (22 mM), also improved the depression of neuronal activity induced by the temperature increase. Adenosine (200 microM) strongly depressed the excitatory postsynaptic response, but not presynaptic action potentials. 8-Cyclopentyl-1,3-dimethylxanthine (8-CPT) (10 microM), an adenosine A1 receptor blocker, attenuated the adenosine-induced depression of the excitatory postsynaptic response. 8-CPT (10 microM) prevented the impairment of the excitatory postsynaptic response induced by the increase of the temperature to 38 degrees C. In contrast, the depression of presynaptic action potential at 38 degrees C was not prevented by 8-CPT (10 microM). N omega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase (NOS) inhibitor, and methylcobalamin (10 microM), a vitamin B12 analogue, attenuated the inhibition of pre- and postsynaptic activities induced by the increase of the temperature to 38 degrees C. Glibenclamide, a KATP channel blocker, did not protect neuronal activity from the effects of the increase of the temperature. These results suggest that the heat-induced depression of neuronal activity is mediated by multiple factors, such as impairment of energy metabolism and increase in extracellular adenosine and nitric oxide (NO) levels in hippocampal neurons. PMID:11830930

Takeya, M

2001-01-01

358

The efficiency calibration and development of environmental correction factors for an in situ high-resolution gamma spectroscopy well logging system  

SciTech Connect

A Gamma Spectroscopy Logging System (GSLS) has been developed to study sub-surface radionuclide contamination. Absolute efficiency calibration of the GSLS was performed using simple cylindrical borehole geometry. The calibration source incorporated naturally occurring radioactive material (NORM) that emitted photons ranging from 186-keV to 2,614-keV. More complex borehole geometries were modeled using commercially available shielding software. A linear relationship was found between increasing source thickness and relative photon fluence rates at the detector. Examination of varying porosity and moisture content showed that as porosity increases, relative photon fluence rates increase linearly for all energies. Attenuation effects due to iron, water, PVC, and concrete cylindrical shields were found to agree with previous studies. Regression analyses produced energy-dependent equations for efficiency corrections applicable to spectral gamma-ray well logs collected under non-standard borehole conditions.

Giles, J.R.

1996-05-01

359

Stress, temperature, heart rate, and hibernating factors in hamsters. [pathophysiological conditions resulting from exposure to zero gravity  

NASA Technical Reports Server (NTRS)

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.

Musacchia, X. J.

1974-01-01

360

Hydrological disturbances of the conductive heat flow in the upper crust: Problems of correcting measured heat flow data  

Microsoft Academic Search

The upper crustal-scale convection of fluids is one of the main factors distorting the conductive geothermal field. Geothermal anomalies caused by water circulation, as a rule, exceed the contributions from other factors (relief, sedimentation, structural and climatic effects). The measured temperature gradient has to be corrected before being used for calculation of the heat flow. In the present work, certain

Bertalan Bodri

1995-01-01

361

[Temperature as a factor of development of psychrotolerant mycelial bacteria complexes in soils of north regions].  

PubMed

It has been demonstrated that complexes of mycelial bacteria (actinomycetes), in which the amount of psychrotolerant actinomycetes reaches hundreds of thousands of CFU/g of the soil (frequently exceeding the portion of mesophilic forms), are developed in peat and podzolic soils of the tundra and taiga at low temperatures. As actinomycetes grow and develop in cold soils, their mycelium increases in length. Use of the molecular in situ hybridization method (fluorescent in situ hybridization, FISH) demonstrated that the portion of metabolically active mycelial actinobacteria exceeds the portion of unicellular actinobacteria in the Actinobacteria phylum. Specific peculiarities of psychrotolerant populations in relation to the spectrum of consumed substrates (histidine, mannitol, saccharose) were established by the method of multirespirometric testing. PMID:23136737

Zenova, G M; Kozhevin, P A; Manucharova, N A; Dubrova, M S; Zviagintsev, D G

2012-01-01

362

Exercise hyperthermia as a factor limiting physical performance - Temperature effect on muscle metabolism  

NASA Technical Reports Server (NTRS)

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.

Kozlowski, S.; Brzezinska, Z.; Kruk, B.; Kaciuba-Uscilko, H.; Greenleaf, J. E.

1985-01-01

363

Factors regulating soil surface CO2 and NOx flux in response to high temperature, pulse water events, and nutrient fertilization  

NASA Astrophysics Data System (ADS)

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 ?moles 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 their inability to account for high temperature emission behavior, responses to irrigation and fertilization events, and influence of vegetation on soil surface trace gas flux.

Oikawa, P. Y.; Grantz, D. A.; Chatterjee, A.; Eberwein, J. R.; Allsman, L. A.; Jenerette, D.

2012-12-01

364

A Non-Linear Control Strategy for Instantaneous Power Factor Correction in 3-ø 4Wire Electrical Systems under Asymmetrical and Non-Linear Loads  

Microsoft Academic Search

A non-linear control strategy in a rotating frame for an active filter based on a voltage source converter shunt topology in a three-phase four-wire electrical system is proposed. The converter in combination with the proposed control strategy guarantees balanced overall currents, unity displacement power factor, and reduced current harmonics in the common coupling point. These features are achieved regardless of

J. R. Sommer; J. R. Espinoza; L. A. Moran

2006-01-01

365

Effect of gray-body interchange factor and radiating temperature on the thermal response of the DT-18 shipping container  

SciTech Connect

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.

Anderson, J.C.; Feldman, M.R.

1992-02-01

366

Factors affecting the wettability of different surface materials with vegetable oil at high temperatures and its relation to cleanability  

NASA Astrophysics Data System (ADS)

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 ? values. Studies of the effect of roughness and surface flaws on wettability revealed that the cos ? 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.

Ashokkumar, Saranya; Adler-Nissen, Jens; Møller, Per

2012-12-01

367

Temperature and air pollution as risk factors for heat stroke in Tokyo, July and August 1980-1995.  

PubMed Central

Heat stroke is associated with prolonged exposures to high air temperatures that usually occur in the summer months of July and August in Tokyo, Japan. Also during July and August, residents of Tokyo are often exposed simultaneously to high concentrations of air pollutants. To assess the impacts of these combined exposures, daily numbers of heat stroke emergency transport cases/million residents for Tokyo were stratified by gender and three groups: 0-14, 15-64; and > 65 years of age, for the months of July and August in 1980-1995. A regression model was constructed using daily maximum temperature (Tmax) and daily average concentrations of NO2 and O3 as model covariates. Classification indices were added to make it possible to compare the expected number of heat stroke cases by age and gender. Lag times of 1-4 days in Tmax and air quality covariates and terms to account for interactions between pairs of model covariates were also included as additional risk factors. Generalized linear models (GLMs), assuming a Poisson error structure for heat stroke emergency transport cases, were used to determine which covariates were significant risk factors for heat stroke for the three age groups of males and females. Same-day Tmax and concentrations of NO2 were the most significant risk factors for heat stroke in all age groups of males and females. The number of heat stroke emergency transport cases/million residents was greater in males than in females in the same age groups. The smallest number of heat stroke emergency transport cases/million residents occurred for females 0-14 years of age and the greatest number of heat stroke emergency transport cases/million residents occurred for males > 65 years of age. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:10544159

Piver, W T; Ando, M; Ye, F; Portier, C J

1999-01-01

368

Perturbative renormalization factors and O(a{sup 2}) corrections for lattice four-fermion operators with improved fermion/gluon actions  

SciTech Connect

In this work we calculate the corrections to the amputated Green's functions of four-fermion operators, in 1-loop lattice perturbation theory. One of the novel aspects of our calculations is that they are carried out to second order in the lattice spacing, O(a{sup 2}). We employ the Wilson/clover action for massless fermions (also applicable for the twisted mass action in the chiral limit) and a family of Symanzik improved actions for gluons. Our calculations have been carried out in a general covariant gauge. Results have been obtained for several popular choices of values for the Symanzik coefficients (Plaquette, Tree-level Symanzik, Iwasaki, TILW and DBW2 action). While our Green's function calculations regard any pointlike four-fermion operators which do not mix with lower dimension ones, we pay particular attention to {Delta}F=2 operators, both parity conserving and parity violating (F stands for flavor: S, C, B). By appropriately projecting those bare Green's functions we compute the perturbative renormalization constants for a complete basis of four-fermion operators and we study their mixing pattern. For some of the actions considered here, even O(a{sup 0}) results did not exist in the literature to date. The correction terms which we calculate (along with our previous O(a{sup 2}) calculation of Z{sub {Psi}}[M. Constantinou, V. Lubicz, H. Panagopoulos, and F. Stylianou, J. High Energy Phys. 10 (2009) 064.][M. Constantinou, P. Dimopoulos, R. Frezzotti, G. Herdoiza, K. Jansen, V. Lubicz, H. Panagopoulos, G. C. Rossi, S. Simula, F. Stylianou, and A. Vladikas, J. High Energy Phys. 08 (2010) 068.][C. Alexandrou, M. Constantinou, T. Korzec, H. Panagopoulos, and F. Stylianou (unpublished).]) are essential ingredients for minimizing the lattice artifacts which are present in nonperturbative evaluations of renormalization constants with the RI{sup '}-MOM method. Our perturbative results, for the matrix elements of {Delta}F=2 operators and for the corresponding renormalization matrices, depend on a large number of parameters: coupling constant, number of colors, lattice spacing, external momentum, clover parameter, Symanzik coefficients, gauge parameter. To make these results most easily accessible to the reader, we have included them in the distribution package of this paper, as an ASCII file named: 4-fermi.m; the file is best perused as Mathematica input. The main results of this work have been applied to improve nonperturbative estimates of the B{sub K}-parameter in N{sub F}=2 twisted mass lattice QCD [M. Constantinou, P. Dimopoulos, R. Frezzotti, K. Jansen, V. Gimenez, V. Lubicz, F. Mescia, H. Panagopoulos, M. Papinutto, G. C. Rossi, S. Simula, A. Skouroupathis, F. Stylianou, and A. Vladikas, arXiv:1009.5606.].

Constantinou, Martha; Panagopoulos, Haralambos; Skouroupathis, Apostolos; Stylianou, Fotos [Department of Physics, University of Cyprus, P.O. Box 20537, Nicosia CY-1678 (Cyprus); Dimopoulos, Petros [Dipartimento di Fisica, Sapienza, Universita di Roma Piazzale A. Moro, I-00185 Rome (Italy); Frezzotti, Roberto [Dipartimento di Fisica, Universita di Roma 'Tor Vergata' Via della Ricerca Scientifica 1, I-00133 Rome (Italy); INFN, Sezione di 'Tor Vergata' c/o Dipartimento di Fisica, Universita di Roma 'Tor Vergata' Via della Ricerca Scientifica 1, I-00133 Rome (Italy); Lubicz, Vittorio [Dipartimento di Fisica, Universita Roma Tre Via della Vasca Navale 84, I-00146 Rome (Italy); INFN, Sezione di Roma Tre c/o Dipartimento di Fisica, Universita Roma Tre Via della Vasca Navale 84, I-00146 Rome (Italy)

2011-04-01

369

Perturbative renormalization factors and O(a2) corrections for lattice four-fermion operators with improved fermion/gluon actions  

NASA Astrophysics Data System (ADS)

In this work we calculate the corrections to the amputated Green’s functions of four-fermion operators, in 1-loop lattice perturbation theory. One of the novel aspects of our calculations is that they are carried out to second order in the lattice spacing, O(a2). We employ the Wilson/clover action for massless fermions (also applicable for the twisted mass action in the chiral limit) and a family of Symanzik improved actions for gluons. Our calculations have been carried out in a general covariant gauge. Results have been obtained for several popular choices of values for the Symanzik coefficients (Plaquette, Tree-level Symanzik, Iwasaki, TILW and DBW2 action). While our Green’s function calculations regard any pointlike four-fermion operators which do not mix with lower dimension ones, we pay particular attention to ?F=2 operators, both parity conserving and parity violating (F stands for flavor: S, C, B). By appropriately projecting those bare Green’s functions we compute the perturbative renormalization constants for a complete basis of four-fermion operators and we study their mixing pattern. For some of the actions considered here, even O(a0) results did not exist in the literature to date. The correction terms which we calculate (along with our previous O(a2) calculation of Z? [M. Constantinou, V. Lubicz, H. Panagopoulos, and F. Stylianou, J. High Energy Phys.JHEPFG1029-8479 10 (2009) 064.10.1088/1126-6708/2009/10/064][M. Constantinou, P. Dimopoulos, R. Frezzotti, G. Herdoiza, K. Jansen, V. Lubicz, H. Panagopoulos, G. C. Rossi, S. Simula, F. Stylianou, and A. Vladikas, J. High Energy Phys.JHEPFG1029-8479 08 (2010) 068.10.1007/JHEP08(2010)068][C. Alexandrou, M. Constantinou, T. Korzec, H. Panagopoulos, and F. Stylianou (unpublished).]) are essential ingredients for minimizing the lattice artifacts which are present in nonperturbative evaluations of renormalization constants with the RI'-MOM method. Our perturbative results, for the matrix elements of ?F=2 operators and for the corresponding renormalization matrices, depend on a large number of parameters: coupling constant, number of colors, lattice spacing, external momentum, clover parameter, Symanzik coefficients, gauge parameter. To make these results most easily accessible to the reader, we have included them in the distribution package of this paper, as an ASCII file named: 4-fermi.m; the file is best perused as Mathematica input. The main results of this work have been applied to improve nonperturbative estimates of the BK-parameter in NF=2 twisted mass lattice QCD [M. Constantinou, P. Dimopoulos, R. Frezzotti, K. Jansen, V. Gimenez, V. Lubicz, F. Mescia, H. Panagopoulos, M. Papinutto, G. C. Rossi, S. Simula, A. Skouroupathis, F. Stylianou, and A. Vladikas, arXiv:1009.5606.].

Constantinou, Martha; Dimopoulos, Petros; Frezzotti, Roberto; Lubicz, Vittorio; Panagopoulos, Haralambos; Skouroupathis, Apostolos; Fotos Stylianou

2011-04-01

370

Entropic corrections to Newton's law  

E-print Network

In this short letter we calculate separately the generalized uncertainty principle (GUP) and self gravitational corrections to the Newton's gravitational formula. We show that for a complete description of the GUP and self-gravity effects, both temperature and the entropy must be modified.

M. R. Setare; D. Momeni; R. Myrzakulov

2010-04-16

371

A Wetness Index Using Terrain-Corrected Surface Temperature and Normalized Difference Vegetation Index Derived from Standard MODIS Products: An Evaluation of Its Use in a Humid Forest-Dominated Region of Eastern Canada  

PubMed Central

In this paper we develop a method to estimate land-surface water content in a mostly forest-dominated (humid) and topographically-varied region of eastern Canada. The approach is centered on a temperature-vegetation wetness index (TVWI) that uses standard 8-day MODIS-based image composites of land surface temperature (TS) and surface reflectance as primary input. In an attempt to improve estimates of TVWI in high elevation areas, terrain-induced variations in TS are removed by applying grid, digital elevation model-based calculations of vertical atmospheric pressure to calculations of surface potential temperature (?S). Here, ?S corrects TS to the temperature value to what it would be at mean sea level (i.e., ?101.3 kPa) in a neutral atmosphere. The vegetation component of the TVWI uses 8-day composites of surface reflectance in the calculation of normalized difference vegetation index (NDVI) values. TVWI and corresponding wet and dry edges are based on an interpretation of scatterplots generated by plotting ?S as a function of NDVI. A comparison of spatially-averaged field measurements of volumetric soil water content (VSWC) and TVWI for the 2003-2005 period revealed that variation with time to both was similar in magnitudes. Growing season, point mean measurements of VSWC and TVWI were 31.0% and 28.8% for 2003, 28.6% and 29.4% for 2004, and 40.0% and 38.4% for 2005, respectively. An evaluation of the long-term spatial distribution of land-surface wetness generated with the new ?S-NDVI function and a process-based model of soil water content showed a strong relationship (i.e., r2 = 95.7%).

Hassan, Quazi K.; Bourque, Charles P.-A.; Meng, Fan-Rui; Cox, Roger M.

2007-01-01

372

Initiation binding repressor, a factor that binds to the transcription initiation site of the histone h5 gene, is a glycosylated member of a family of cell growth regulators [corrected  

PubMed Central

Initiation binding repressor [corrected] (IBR) is a chicken erythrocyte factor (apparent molecular mass, 70 to 73 kDa) that binds to the sequences spanning the transcription initiation site of the histone h5 gene, repressing its transcription. A variety of other cells, including transformed erythroid precursors, do not have IBR but a factor referred to as IBF (68 to 70 kDa) that recognizes the same IBR sites. We have cloned the IBR cDNA and studied the relationship of IBR and IBF. IBR is a 503-amino-acid-long acidic protein which is 99.0% identical to the recently reported human NRF-1/alpha-Pal factor and highly related to the invertebrate transcription factors P3A2 and erected wing gene product (EWG). We present evidence that IBR and IBF are most likely identical proteins, differing in their degree of glycosylation. We have analyzed several molecular aspects of IBR/F and shown that the factor associates as stable homodimers and that the dimer is the relevant DNA-binding species. The evolutionarily conserved N-terminal half of IBR/F harbors the DNA-binding/dimerization domain (outer limits, 127 to 283), one or several casein kinase II sites (37 to 67), and a bipartite nuclear localization signal (89 to 106) which appears to be necessary for nuclear targeting. Binding site selection revealed that the alternating RCGCRYGCGY consensus constitutes high-affinity IBR/F binding sites and that the direct-repeat palindrome TGCGCATGCGCA is the optimal site. A survey of genes potentially regulated by this family of factors primarily revealed genes involved in growth-related metabolism. PMID:8524232

Gomez-Cuadrado, A; Martin, M; Noel, M; Ruiz-Carrillo, A

1995-01-01

373

A Sporulation Factor Is Involved in the Morphological Change of Clostridium perfringens Biofilms in Response to Temperature  

PubMed Central

Biofilm formation has been associated with bacterial pathogenesis, such as nosocomial and chronic infections, as the resistance of biofilms to environmental stresses has increased. Clostridium perfringens is a Gram-positive spore-forming anaerobic pathogen. This organism survives antibiotic treatment through the formation of biofilms or spores, but the environmental and regulatory factors involved in the biofilm formation remain unclear. Here, we observed that temperature regulates C. perfringens biofilm morphology. At 37°C, C. perfringens adhered to the substrate surface and formed a flat, thin biofilm, herein referred to as adhered biofilm. However, at 25°C, this bacterium did not adhere and produced a threadlike extracellular matrix, forming a viscous, thick biofilm, herein referred to as pellicle biofilm. Pellicle biofilm formation requires the sporulation master regulator, Spo0A, and the toxin regulator, CtrAB, and is enhanced in the absence of the global repressor, AbrB. These transcriptional regulator genes are regulated by each other and temperature. Adhered-biofilm formation requires AbrB and pilA2, which encodes a component of type IV pili (TFP). TFP expression was activated at 37°C and regulated through Spo0A, AbrB, and CtrAB. These results indicate that the morphology of C. perfringens biofilm is dependent on temperature through the differential production of extracellular matrix and the activity of TFP. Moreover, pellicle biofilm formation is involved in sporulation and toxin production. Here, we demonstrated that clostridial biofilm formation is closely associated with sporulation and that the morphological change of the biofilms could play an important role in the pathogenesis of this organism. PMID:24509316

Obana, Nozomu; Nakamura, Kouji

2014-01-01

374

Delivery of Full-Length Factor VIII Using a piggyBac Transposon Vector to Correct a Mouse Model of Hemophilia A  

PubMed Central

Viral vectors have been used for hemophilia A gene therapy. However, due to its large size, full-length Factor VIII (FVIII) cDNA has not been successfully delivered using conventional viral vectors. Moreover, viral vectors may pose safety risks, e.g., adverse immunological reactions or virus-mediated cytotoxicity. Here, we took advantages of the non-viral vector gene delivery system based on piggyBac DNA transposon to transfer the full-length FVIII cDNA, for the purpose of treating hemophilia A. We tested the efficiency of this new vector system in human 293T cells and iPS cells, and confirmed the expression of the full-length FVIII in culture media using activity-sensitive coagulation assays. Hydrodynamic injection of the piggyBac vectors into hemophilia A mice temporally treated with an immunosuppressant resulted in stable production of circulating FVIII for over 300 days without development of anti-FVIII antibodies. Furthermore, tail-clip assay revealed significant improvement of blood coagulation time in the treated mice.piggyBac transposon vectors can facilitate the long-term expression of therapeutic transgenes in vitro and in vivo. This novel gene transfer strategy should provide safe and efficient delivery of FVIII. PMID:25126862

Matsui, Hideto; Fujimoto, Naoko; Sasakawa, Noriko; Ohinata, Yasuhide; Shima, Midori; Yamanaka, Shinya; Sugimoto, Mitsuhiko; Hotta, Akitsu

2014-01-01

375

Metabolic fingerprinting of gilthead seabream (Sparus aurata) liver to track interactions between dietary factors and seasonal temperature variations  

PubMed Central

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

da Costa, Ana M.R.; Conceicao, Luis E.C.; Dias, Jorge P.; Rodrigues, Pedro M.L.; Richard, Nadege

2014-01-01

376

Static and Dynamic Structure Factors with Account of the Ion Structure for High-temperature Alkali and Alkaline Earth Plasmas  

NASA Astrophysics Data System (ADS)

The electron-electron, electron-ion, ion-ion and charge-charge static structure factors (SSF) are calculated for alkali and Be^2+ plasmas at various temperatures and concentrations using the method described by G. Gregori et al., Phys. Rev. E 74, 026402 (2006); High Energy Density Phys. 3, 99 (2007). The dynamic structure factors (DSF) for alkali plasmas are calculated using the method of moments developed by V. M. Adamjan et al., High. Temp. 21, 307 (1983). In both methods the screened Hellmann-Gurskii-Krasko potential, obtained on the basis of Bogolyubov's method, has been used taking into account not only the quantum-mechanical effects but also reflects important features of the ion structure (S. Sadykova et al., Contrib. Plasma Phys. 49, 76 (2009)). Our results on the SSFs for Be^2+ plasma deviate from the data obtained by Gregori et al., while our DSFs are in a reasonable agreement with those of S. V. Adamjan et al., Phys. Rev. E 48, 2067 (1993). We conclude that the short range forces, which we take into account by means of the HGK model potential, which deviates from the Coulomb and Deutsch ones, employed by S. V. Adamjan et al. and Gregori et al. correspondingly, influence the SSFs and DSFs significantly.

Polatovna Sadykova, Saltanat; Ebeling, Werner; Tkachenko, Igor M.

2010-11-01

377

Boots Corrections Syllabus Page 1 Corrections  

E-print Network

and prisons, alternatives to incarceration (e.g., probation and parole), capital punishment, and the public of punishment and treatment. Emphasis will be placed on correctional law, policies, practices, issues) explain the history of corrections and the rationales for punishment 2) discuss the contemporary issues

O'Toole, Alice J.

378

Correction of Diabetic Erectile Dysfunction with Adipose Derived Stem Cells Modified with the Vascular Endothelial Growth Factor Gene in a Rodent Diabetic Model  

PubMed Central

The aim of this study was to determine whether adipose derived stem cells (ADSCs) expressing vascular endothelial growth factor (VEGF) gene can improve endothelial function, recover the impaired VEGF signaling pathway and enhance smooth muscle contents in a rat diabetic erectile dysfunction (DED) model. DED rats were induced via intraperitoneal injection of streptozotocin (40 mg/kg), and then screened by apomorphine (100 µg/kg). Five groups were used (n?=?12/group)–Group 1 (G1): intracavernous injection of lentivirus-VEGF; G2: ADSCs injection; G3: VEGF-expressing ADSCs injection; G4: Phosphate buffered saline injection; G1–G4 were DED rats; G5: normal rats. The mean arterial pressure (MAP) and intracavernosal pressure (ICP) were measured at days 7 and 28 after the injections. The components of the VEGF system, endothelial, smooth muscle, pericytes markers in cavernoursal tissue were assessed. On day 28 after injection, the group with intracavernosum injection of ADSCs expressing VEGF displayed more efficiently and significantly raised ICP and ICP/MAP (p<0.01) than those with ADSCs or lentivirus-VEGF injection. Western blot and immunofluorescent analysis demonstrated that improved erectile function by ADSCs-VEGF was associated with increased expression of endothelial markers (VEGF, VEGF R1, VEGF R2, eNOS, CD31 and vWF), smooth muscle markers (a-actin and smoothelin), and pericyte markers (CD146 and NG2). ADSCs expressing VEGF produced a therapeutic effect and restored erectile function in diabetic rats by enhancing VEGF-stimulated endothelial function and increasing the contents of smooth muscle and pericytes. PMID:24023647

Wu, Rongpei; Guan, Xuan; Ouyang, Bin; Huang, Yanping; Xiao, Haipeng; Luo, Daosheng; Atala, Anthony; Zhang, Yuanyuan; Deng, Chunhua

2013-01-01

379

Greenland palaeotemperatures derived from GRIP bore hole temperature and ice core isotope profiles  

Microsoft Academic Search

Modelling the temperature profile along the GRIP deep bore at the summit of the Greenland ice sheet leads to conversion factors that allow interpretation of the dated stable isotope profile as a climatic temperature record spanning the last 113,000 years. When corrected for surface elevation changes, the late glacial to Boreal temperature shift appears to have been 22°C in central

Sigfus J. Johnsen; Dorthe Dahl-Jensen; Willi Dansgaard; Niels Gundestrup

1995-01-01

380

Partial atmospheric correction with adaptive optics  

Microsoft Academic Search

Some numerical experiments performed to test the concept of partial atmospheric correction with adaptive optics are described. Simulated one-dimensional atmospheric wave fronts are generated, correction factors are applied to the wave fronts for various spatial scales, and transfer functions, point-spread fucntions, and images are calculated for intercomparison. The results support the thesis that substantial improvement in imaging capabilities could be

Peter Nisenson; Richard Barakat

1987-01-01

381

Choices in Correction of Aphakia during Vitrectomy  

Microsoft Academic Search

Phacoemulsification with an intraocular lens implant is a safe and effective means of correction of visual loss from cataract. The high frequency of this procedure world wide means inevitable direct surgical complications will be numerous even though infrequent. The approach to correcting aphakia following complicated cataract surery is dependent on multiple factors including the degree to which the capsular bag

Andrew Bastawrous; Craig Parkes; Som Prasad

2011-01-01

382

Quantum Error Correction Beyond Completely Positive Maps  

E-print Network

By introducing an operator sum representation for arbitrary linear maps, we develop a generalized theory of quantum error correction (QEC) that applies to any linear map, in particular maps that are not completely positive (CP). This theory of "linear quantum error correction" is applicable in cases where the standard and restrictive assumption of a factorized initial system-bath state does not apply.

A. Shabani; D. A. Lidar

2006-10-05

383

Tumor necrosis factor is involved in chlorpyrifos--induced changes in core temperature in the female rat.  

PubMed

Chlorpyrifos (CHP), an OP-based pesticide, induces hypothermia in the rat followed by a fever that persists for several days. The cytokine, tumor necrosis factor-alpha (TNF), is induced by lipopolysaccharide (LPS) and released during fever and has both pyrogenic and cryogenic (i.e. antipyretic) properties. Administering antibodies to TNF (anti-TNF) is known to disrupt fever from infection. Thus, the purpose of this study was to examine whether anti-TNF also disrupts CHP-induced changes in body temperature of the female Long-Evans rat. A positive effect would suggest a role of TNF in the etiology of OP toxicity. In study one, rats were given either saline or anti-TNF (50,000 units, i.p.). Three hours later, animals were given corn oil (CO) or 25 mg/kg CHP by oral gavage in the morning. In study two, rats were given anti-TNF followed by CO or 10 mg/kg CHP in the afternoon. Core temperature and motor activity were monitored continuously by telemetry. In study one, anti-TNF (50,000 units) had no effect on the hypothermic response to 25 mg/kg CHP. However, anti-TNF treated animals maintained higher fevers 3 days (48-96 h post-injection) after CHP treatment. In study two, anti-TNF attenuated the hypothermic response induced by 10 mg/kg CHP but had no effect on the magnitude of the delayed fever. Overall, 25 mg/kg CHP elicited a longer period of hypothermia and delayed fever compared to 10 mg/kg CHP. Anti-TNF pretreatment attenuated the hypothermic response at the lower CHP dose and exacerbated the fever at the higher CHP dose. Anti-TNF also attenuated the hypothermic effect of high doses of LPS and exacerbated LPS-induced fever. These data indicate that endogenously produced TNF is involved in the etiology of CHP mediated hypothermia and fever. PMID:10514030

Rowsey, P J; Gordon, C J

1999-09-20

384

Correcting Correlation Function Measurements  

E-print Network

Correlation functions measured as a function of $\\Delta \\eta, \\Delta \\phi$ have emerged as a powerful tool to study the dynamics of particle production in nuclear collisions at high energy. They are however subject, like any other observables, to instrumental effects which must be properly accounted for to extract meaningful physics results. We compare the merits of several techniques used towards measurement of these correlation functions in nuclear collisions. We discuss and distinguish the effects of finite acceptance, and detection efficiency that may vary with collision parameters such as the position of the event in the detector and the instantaneous luminosity of the beam. We focus in particular on instrumental effects which break the factorization of the particle pair detection efficiency, and describe a technique to recover the robustness of correlation observables. We finally introduce a multi-dimensional weight method to correct for efficiencies that vary simultaneously with particle pseudo rapidity, azimuthal angle, transverse momentum, and the collision vertex position. The method can be generalized to account for any number of "event variables" that may break the factorability of the pair efficiency.

Shantam Ravan; Prabhat Pujahari; Sidharth Prasad; Claude A. Pruneau

2013-11-15

385

Thermal and Nonthermal Electron-ion Bremsstrahlung Spectrum from High-Temperature Plasmas  

NASA Technical Reports Server (NTRS)

Electron-ion bremsstrahlung radiation from high-temperature plasmas is investigated. The first- and second-order Coulomb corrections in the nonrelativistic bremsstrahlung radiation power are obtained by the Elwert-Sommerfeld factor. In this paper, two cases of the electron distributions, the thermal and nonthermal power-law distributions, are considered. The inclusion of Coulomb corrections is necessary in deducing correctly the electron distribution function from radiation data. These results provide the correct information of electron distributions in high-temperature plasmas, such as in inertial confinement fusion plasmas and in the astrophysical hot thermal and nonthermal x-ray sources.

Jung, Young-Dae

1994-01-01

386

Research in Correctional Rehabilitation.  

ERIC Educational Resources Information Center

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)…

Rehabilitation Services Administration (DHEW), Washington, DC.

387

49 CFR 659.37 - Corrective action plans.  

Code of Federal Regulations, 2010 CFR

...require the development of a corrective action plan for the following: (1) Results from investigations, in which identified causal and contributing factors are determined by the rail transit agency or oversight agency as requiring corrective actions;...

2010-10-01

388

INTEGRATING NEPHELOMETER RESPONSE CORRECTIONS FOR BIMODAL SIZE DISTRIBUTIONS  

EPA Science Inventory

Correction factors are calculated for obtaining true scattering extinction coefficients from integrating nephelometer measurements. The corrections are based on the bimodal representation of ambient aerosol size distributions, and take account of the effects of angular truncation...

389

Influence of manufacturing factors on physical stability and solubility of solid dispersions containing a low glass transition temperature drug.  

PubMed

In this study, we investigated the effect of manufacturing factors such as particle size, water content and manufacturing method on the physical stability and solubility of solid dispersion formulations of a low-glass-transition-temperature (T(g)) drug. Solid dispersions were prepared from polyvinylpyrrolidone (PVP) and hydroxypropylmethylcellulose (HPMC) by hot melt extrusion or spray drying. Water content of solid dispersions prepared by hot melt extrusion determined by dynamic moisture sorption measurement was increased drastically with relative humidity below a certain level of particle size. The blends with a lower water content (0.8%) prepared by hot melt extrusion during storage were more stable than those with a higher water content (3.5%) prepared by spray drying, which caused rapid recrystallization. Physical stability in the hot melt blends may be attributed to reduced molecular mobility due to a higher T(g). Dissolution study revealed that solid dispersions prepared by hot melt extrusion with the smallest particle size showed decreased solubility, attributed to reduced wetting properties (surface energy), which is not predictable by the Noyes-Whitney equation. Taken together, these results indicate that the control of particle size concerned in water content or wetting properties is critical to ensuring the physical stability or enhancing solubility of low-T(g) drugs. Further, hot melt extrusion, which can reduce water content, is a suitable manufacturing method for solid dispersions of low-T(g) drugs. PMID:23124559

Sakurai, Atsushi; Sako, Kazuhiro; Maitani, Yoshie

2012-01-01

390

Underground storage tank corrective action technologies  

NASA Astrophysics Data System (ADS)

The document contains information on corrective action technologies for releases from underground storage tanks (UST). It probes general background information on UST construction techniques, leak detection methods, and failure mechanisms. It also addresses transport pathways of released substances, techniques for evaluating the extent of a release, factors influencing risk to human health and the environment, techniques for selecting initial corrective-action response technologies, and detailed technical profiles of corrective action technologies. Emphasis is on corrective actions associated with releases from gasoline and petroleum USTs.

Cochran, R.

1987-01-01

391

American Correctional Association  

NSDL National Science Digital Library

The American Correctional Association is the oldest, and largest international correctional association in the world. ACA serves all disciplines within the corrections profession and is dedicated to excellence in every aspect of the field. The topics covered on this site are wide-ranging, from professional development and certification, to standards and accreditation, network and consulting, research and publications, conferences and exhibits and technology and testing. ACA is a valuable resource for anyone interested in the American Corrections system. A key feature of the website, is that it provides information about professional development programs and workshops as well as professional certification for an adult and juvenile correctional staff.

2006-11-12

392

Corrective Action Glossary  

SciTech Connect

The glossary of technical terms was prepared to facilitate the use of the Corrective Action Plan (CAP) issued by OSWER on November 14, 1986. The CAP presents model scopes of work for all phases of a corrective action program, including the RCRA Facility Investigation (RFI), Corrective Measures Study (CMS), Corrective Measures Implementation (CMI), and interim measures. The Corrective Action Glossary includes brief definitions of the technical terms used in the CAP and explains how they are used. In addition, expected ranges (where applicable) are provided. Parameters or terms not discussed in the CAP, but commonly associated with site investigations or remediations are also included.

Not Available

1992-07-01

393

Radiometric correction of LANDSAT data  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. The six independent sensors of the multispectral band scanner are supposed to be identical; however, in actual practice, they may have different gain settings and offset factors, which result in the effect known as stripping (black lines at regular intervals) of the imagery. A simple two parameter method to correct the gain settings and offset factors of each of the sensors with respect to one sensor, taken as reference, was developed. This method assumes: (1) the response of a detector varies linearly with the radiance of radiation received, and (2) the means, as well as the standard deviations, of a reasonably large number of pixels, in a given wavelength band, are equal for each of the detectors for the radiometrically corrected data.

Dejesusparada, N.; Kumar, R. (principal investigator); Cavalcanti, L. A.

1977-01-01

394

Nuclear correction factors from neutrino DIS  

E-print Network

Neutrino Deep Inelastic Scattering on nuclei is an essential process to constrain the strange quark parton distribution functions in the proton. The critical component on the way to using the neutrino DIS data in a proton PDF analysis is understanding the nuclear effects in parton distribution functions. We parametrize these effects by nuclear parton distribution functions and we use this framework to analyze the consistency of neutrino DIS data with other nuclear data.

K. Kovarik

2011-07-15

395

EDITORIAL: Politically correct physics?  

NASA Astrophysics Data System (ADS)

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 same game. In today's PC physics, no such complications arise because all forms of energy are equal and unlabelled. I accept the reasoning behind this - that understanding processes is more important than attaching labels - but what am I supposed to call ½mv2, mgh and mc??? On which subject.... What am I allowed to say about heat? It seems that objects can be heated up. I can switch on the central heating. But I cannot get heat from a Bunsen burner. In PC physics, heat is banned - at least as a noun. Instead, I have to talk about 'energy transferred because of a temperature difference'. And I must stop saying 'transferred' in circumstances where I really mean 'transformed'. I find it difficult to argue with the logic behind the new approach to energy, but the loss of such an elegantly simple word as 'heat' is proving a severe restriction on my use of language. The loss is especially galling because engineers will go on talking about heat engines, heat pumps and heat sinks. In primary schools, saucepans will still conduct heat, and the Sun will continue to give off heat and light. Moreover, I suspect that most teachers will be using 'heat' in the privacy of the classroom, even if they won't admit to it in public. We shall all become closet heatists. Before PC physics takes over by stealth, we need a full and open debate on what is or isn't conceptually acceptable for students at different stages. Perhaps we need a conference. If so, I will be there at the back with my banner. But this time, it won't read 'Save the whale' or 'Save the rainforests'. It will read 'Save heat', or maybe 'Save all forms of energy'.

Pople Deputy Editor, Stephen

1997-03-01

396

Temperature Anomalies and Mortality Events in Marine Communities: Insights on Factors behind Differential Mortality Impacts in the NW Mediterranean  

PubMed Central

Two large-scale mass mortality events (MMEs) of unprecedented extent and severity affecting rocky benthic communities occurred during the summers of 1999 and 2003 along the coasts of the NW Mediterranean Sea. These mortality outbreaks were associated with positive thermal anomalies. In this study, we performed an analysis of inter-regional and inter-annual differences in temperature (T) conditions associated with MMEs of the red gorgonian Paramuricea clavata by analyzing high resolution T time series (hourly records for 3 to 8 years) from four regions of the NW Mediterranean with differing hydrological conditions and biological impacts. High resolution records allowed a detailed analysis using classical and new descriptors to characterize T anomalies. We were able to determine that the MMEs were triggered by two main types of positive thermal anomalies, with the first type being characterized by short periods (2 to 5 days) with high Mean T reaching more than 27°C in some regions and being associated with high intra-day and intra-period variability, while the second type of anomaly presented long duration (near one month) at warm T (24°C) with low intra-period variability. Inter-regional patterns arose; some regions displayed both types of anomalies, while others exhibited only one type. The results showed that T conditions should be considered as the main factor that explains the observed inter-regional and inter-annual differences in mortality impacts. In explaining these differences, the late timing of T anomalies, in addition to their magnitude was found to be determinant. Finally, by combining thermotolerance experimental data with the maximal T stress conditions observed in the four regions, we were able to determine the differential risk of mass mortality across regions. We conclude that expanding high resolution T series is important for the development of sound management and conservation plans to protect Mediterranean marine biodiversity in the face of climate change. PMID:21931615

Crisci, Carolina; Bensoussan, Nathaniel; Romano, Jean-Claude; Garrabou, Joaquim

2011-01-01

397

Determination and Use of the Local Recovery Factor for Calculating the Effectiveness Gas Temperature for Turbine Blades / Jack B. Esgar and Alfred L. Lea  

NASA Technical Reports Server (NTRS)

In an in experimental investigation of local recovery factors for a blade having a pressure distribution similar to that of a typical reaction-type turbine blade, it a was found that the recovery factors were essentially independent of Mach number, Reynolds number, pressure gradient, and position on the blade surface except for regions where the boundary layer was probably in the transition range from laminar to turbulent. The recommended value of local subsonic recovery factor for use in calculating the effective gas temperature for gas turbine blades was 0.89.

Esgar, Jack B; Lea, Alfred L

1951-01-01

398

Atmospheric Corrections in Coastal Altimetry  

NASA Astrophysics Data System (ADS)

The range measurements from the altimeter are associated with a large number of geophysical corrections which needs special attention near coasts and the shallow water regions. The corrections due to ionosphere, dry and wet troposphere and that due to sea state are of primary importance in altimetry. Water vapor dominates the wet tropospheric corrections by several factors which is more complex with higher spatio-temporal variations and thus needs a careful attention near coasts. In addition to this rain is one of the major atmospheric phenomena which attenuate the backscatter altimeter measurements which in turn affect the altimeter derived wind and wave measurements. Thus during rain events utmost care should be taken while deriving the altimeter wind speeds and wave heights. The first objective of the present study involves the comparison of the water vapor corrections estimated from radiosonde measurements near the coastal regions with the model estimated corrections applied in the altimeter range measurements. Analysis has been performed for the Coastal Altimeter products provided by the PISTACH to observe these corrections. The second objective is to estimate the rain rate using altimeter backscatter measurements. The differential attenuation of KU band over C band due to rain has been utilized to identify the rain events and to estimate the amount of rain fall. JASON-2 altimeter data during two tropical cyclonic events over Bay of Bengal have been used for this purpose. An attempt is made to compare the estimated rain rate from altimeter measurements with the other available collocated satellite observations like KALPANA and TRMM-TMI. The results are encouraging and can be used to provide valid rain flags in the altimeter products in addition to the radiometer rain flags.

Antonita, Maria; Kumar, Raj

2012-07-01

399

Coincidence summing corrections applied to volume sources.  

PubMed

The numerical calculation of coincidence summing corrections requires both the total and full-energy peak efficiencies to be included in the corrective factors. Moreover, in the case of volume sources, the coincidence probability depends on the position of the photon emission inside the radioactive sample, thus it is necessary to calculate the coincidence summing corrective factors by integrating the elemental contributions for the entire volume. The software ETNA calculates coincidence summing corrective factors according to a deterministic method, for volume sources, two approaches are included in the software: the "simplified" calculation uses directly the efficiency of the volume source like in the case of point source, and the "complete" calculation performs the volume integration. To assess the difference between these, different geometrical cases are tested for several radionuclides using both methods. PMID:22410298

Lépy, Marie-Christine; Ferreux, Laurent; Pierre, Sylvie

2012-09-01

400

Magnesium correction to the NaKCa chemical geothermometer  

USGS Publications Warehouse

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.

Fournier, R.O.; Potter, R.W., II

1979-01-01