Note: This page contains sample records for the topic temperature correction factor from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
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

Temperature Correction Schemes  

NASA Astrophysics Data System (ADS)

The pro and contra for using temperature correction are discussed on the basis of our linearization scheme and our implementation of an Unsöld-Lucy temperature correction. I will show the improvements which partly overcome the typical weakness of the UL-scheme as well as our generalization to non-LTE.

Dreizler, S.

2003-01-01

3

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

SciTech Connect

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

La Russa, Daniel J.; McEwen, Malcolm; Rogers, D. W. O. [Carleton Laboratory for Radiotherapy Physics, Ottawa Carleton Institute of Physics, Carleton University, Ottawa, ON K1S 5B6 (Canada); Ionizing Radiation Standards, National Research Council of Canada, M-35 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Carleton Laboratory for Radiotherapy Physics, Ottawa Carleton Institute of Physics, Carleton University, Ottawa, ON K1S 5B6 (Canada)

2007-12-15

4

Temperature correction in conductivity measurements  

USGS Publications Warehouse

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

Smith, Stanford H.

1962-01-01

5

Downhole Pressure Gauge Temperature Correction Model Design  

Microsoft Academic Search

During the pressure measurement, the measured value may drift with the changing temperature; therefore a special mathematical model should be established to correct the measurement. Several temperature points were selected when calibrating, and the line fitting with least square method was used for test data of pressure at every temperature point. Between the two adjacent temperature points, the piecewise linear

Xiwei Yang; Tianxiao Yang

2010-01-01

6

Temperature corrections in routine spirometry.  

PubMed

Forced expiratory volume (FEV1) and forced vital capacity (FVC) were measured in nine normal subjects with three Vitalograph and three rolling seal spirometers at three different ambient temperatures (4 degrees C, 22 degrees C, 32 degrees C). When the results obtained with the rolling seal spirometer were converted to BTPS the agreement between measurements in the three environments improved, but when the Vitalograph measurements obtained in the hot and cold rooms were converted an error of up to 13% was introduced. The error was similar whether ambient or spirometer temperatures were used to make the conversion. In an attempt to explain the behaviour of the Vitalograph spirometers the compliance of their bellows was measured at the three temperatures. It was higher at the higher temperature (32 degrees C) and lower at the lower temperature (4 degrees C) than at the normal room temperature. These changes in instrument compliance could account for the differences in measured values between the two types of spirometer. It is concluded that the ATPS-BTPS conversion is valid and necessary for measurements made with rolling seal spirometers, but can cause substantial error if it is used for Vitalograph measurements made under conditions other than normal room temperature. PMID:6495245

Cramer, D; Peacock, A; Denison, D

1984-10-01

7

Finite temperature corrections to relic density calculations  

SciTech Connect

In this paper we evaluate finite temperature corrections to the dark matter relic density within the context of minimal supersymmetry with a neutralino as the lightest supersymmetric partner (LSP). We identify several regions of parameter space where the weakly interacting massive particle (WIMP) annihilation cross section is especially sensitive to small corrections to the underlying parameters. In these regions, finite temperature effects have the potential to be important. However, we shall show by explicit calculation that these effects are small. In the regions we investigated, the maximal corrections are on the order of 10{sup -4} and are therefore negligible compared with theoretical and experimental uncertainties.

Wizansky, Tommer [Stanford Linear Accelerator Center Stanford University, Stanford, California 94309 (United States)

2006-09-15

8

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

9

Interaction corrections at intermediate temperatures: dephasing time  

Microsoft Academic Search

We calculate the temperature dependence of weak localization correction in two dimensional system at arbitrary relation between temperature, T and the elastic mean free time. We described the crossover in the dephasing time tau_\\\\varphi(T) between the high temperature, 1\\/ tau_\\\\varphi ~= T^2 ln T, and the low temperature 1\\/ tau_\\\\varphi ~= T behaviors. The prefactors in these dependences are not

Boris Narozhny; Gabor Zala; Igor Aleiner

2002-01-01

10

Effective Temperature Scale and Bolometric Corrections  

Microsoft Academic Search

The conversion from an observational quantity, such as the color index or the spectral type, to the effective temperature (Teff) of a star is known as the effective TEMPERATURE SCALE. Bolometric corrections are required in the calculation of the luminosity of a star if the flux from the star has not been observed over the entire ELECTROMAGNETIC SPECTRUM....

R. Gray

2000-01-01

11

Peroneal nerve conduction velocity: the importance of temperature correction.  

PubMed

The relationship between skin surface temperature, near nerve temperature and nerve conduction velocity (NCV) of the peroneal nerve was studied in normal and diabetic subjects to determine a peroneal NCV-treatment correction factor and to investigate whether temperature correction of NCV reduces its variability. Twenty normal subjects (age 21 to 72 years, mean 44, SD 17) were tested for peroneal NCV, skin and near nerve temperatures bilaterally at ambient temperature (mean 26.6C). Tests were repeated after cooling the lower extremity to a skin temperature of 26C, and at skin temperatures of 28 and 29C as the legs were allowed to gradually warm. An additional 20 normal and 20 diabetic subjects were tested weekly at ambient temperature for peroneal NCV and skin temperature, measured at 15cm above the lateral malleolus. The results showed a linear relationship between skin temperature, near nerve temperature and peroneal NCV (p less than 0.001). Peroneal NCV was altered 2.0 meters per second per degree (C) change in skin and near nerve temperature (p less than 0.001). When using our formula, peroneal motor NCV corrected = 2.0 [32 - skin temp(C)] + NCV (m/sec), for correction of peroneal NCV to a standard skin temperature of 32C, it was found that temperature corrected NCV were less variable (p less than 0.05) than noncorrected NCV in the same diabetic subjects. These results indicate that temperature corrected NCV should be calculated routinely during clinical NCV examinations of patients with peripheral neuropathies. PMID:7283685

Halar, E M; DeLisa, J A; Brozovich, F V

1981-09-01

12

Nerve conduction studies in upper extremities: skin temperature corrections.  

PubMed

The relationship of skin to near nerve (NN) temperature and to nerve conduction velocity (NCV) and distal latency (DL) was studied in 34 normal adult subjects before and after cooling both upper extremities. Median and ulnar motor and sensory NCV, DL, and NN temperature were determined at ambient temperature (mean X skin temp = 33 C) and after cooling, at approximately 26, 28, and 30 C of forearm skin temperature. Skin temperatures on the volar side of the forearm, wrist, palm, and fingers and NN temperature at the forearm, midpalm, and thenar or hypothenar eminence were compared with respective NCV and DL. Results showed a significant linear correlation between skin temperature and NN temperature at corresponding sites (r2 range, 0.4-0.84; p less than 0.005). Furthermore, both skin and NN temperatures correlated significantly with respective NCV and DL. Midline wrist skin temperature showed the best correlation to NCV and DL. Median motor and sensory NCV were altered 1.5 and 1.4m/sec/C degree and their DL 0.2 msec/C degree of wrist skin temperature change, respectively. Ulnar motor and sensory NCV were changed 2.1 and 1.6m/sec/C degree respectively, and 0.2 msec/C degree wrist temperature for motor and sensory DL. Average ambient skin temperature at the wrist (33 C) was used as a standard skin temperature in the temperature correction formula: NCV or DL(temp corrected) = CF(Tst degree - Tm degree) + obtained NCV or DL, where Tst = 33 C for wrist, Tm = the measured skin temperature, and CF = correction factor of tested nerve. Use of temperature correction formula for NCV and DL is suggested in patients with changed wrist skin temperature outside 29.6-36.4C temperature range. PMID:6615178

Halar, E M; DeLisa, J A; Soine, T L

1983-09-01

13

49 CFR 325.79 - Application of correction factors.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Application of correction factors. 325.79 Section 325.79...MOTOR CARRIER NOISE EMISSION STANDARDS Correction Factors § 325.79 Application of correction factors. (a) If two correction...

2010-10-01

14

49 CFR 325.79 - Application of correction factors.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Application of correction factors. 325.79 Section 325.79...MOTOR CARRIER NOISE EMISSION STANDARDS Correction Factors § 325.79 Application of correction factors. (a) If two correction...

2009-10-01

15

Factors of Addiction: New Jersey Correctional Population  

ERIC Educational Resources Information Center

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

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

2007-01-01

16

A temperature correction method for expanding atmospheres  

NASA Astrophysics Data System (ADS)

Model atmospheres form the basis for the interpretation of stellar spectra. A major problem in those model calculations is to establish the temperature stratification from the condition of radiative equilibrium. Dealing with non-LTE models for spherically expanding atmospheres of Wolf-Rayet stars, we developed a new temperature correction method. Its basic idea dates back to 1955 when it was proposed by Unsöld for grey, static and plane-parallel atmospheres in LTE. The equations were later generalized to the non-grey case by Lucy. In the present paper we furthermore drop the Eddington approximation, proceed to spherical geometry and allow for expansion of the atmosphere. Finally the concept of an ``approximate lambda operator'' is employed to speed up the convergence. Tests for Wolf-Rayet type models demonstrate that the method works fine even in situations of strong non-LTE.

Hamann, W.-R.; Gräfener, G.

2003-11-01

17

Single phase power factor correction: a survey  

Microsoft Academic Search

New recommendations and future standards have increased the interest in power factor correction circuits. There are multiple solutions in which line current is sinusoidal. In addition, a great number of circuits have been proposed with nonsinusoidal line current. In this paper, a review of the most interesting solutions for single phase and low power applications is carried out. They are

Oscar García; José A. Cobos; Roberto Prieto; Pedro Alou; Javier Uceda

2003-01-01

18

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

19

Factorization, power corrections, and the pion form factor  

NASA Astrophysics Data System (ADS)

This paper is an investigation of the pion form factor utilizing recently developed effective field theory techniques. The primary results reported are both the transition and electromagnetic form factors are corrected at order ?/Q due to time ordered products which account for deviations of the pion from being a state composed purely of highly energetic collinear quarks in the lab frame. The usual higher twist wave function corrections contribute only at order ?2/Q2, when the quark mass vanishes. In the case of the electromagnetic form factor the ?/Q power correction is enhanced by a power of 1/?s(Q) relative to the leading order result of Brodsky and Lepage, if the scale ?(?Q) is nonperturbative. This enhanced correction could explain the discrepancy with the data.

Rothstein, Ira Z.

2004-09-01

20

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 30 m 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

21

Temperature corrections to conformal field theory  

Microsoft Academic Search

We consider finite temperature dynamical correlation functions in the interacting delta-function Bose gas. In the low-temperature limit the asymptotic behaviour of correlation functions can be determined from conformal field theory. In the present work we determine the deviations from conformal behaviour at low temperatures.

F. H. L. Eßler; V. E. Korepin; F. T. Latrémolière

1998-01-01

22

Temperature corrections to conformal field theory  

Microsoft Academic Search

:   We consider finite temperature dynamical correlation functions in the interacting delta-function Bose gas. In the low-temperature\\u000a limit the asymptotic behaviour of correlation functions can be determined from conformal field theory. In the present work\\u000a we determine the deviations from conformal behaviour at low temperatures.

F. H. L. Eßler; Vladimir E. Korepin; F. T. Latrémolière

1998-01-01

23

Temperature corrections for the VIZ and VAISALA radiosondes  

SciTech Connect

The NWS VIZ radiosonde and the Vaisala RS-80 radiosondes are used worldwide to obtain upper air measurements of atmospheric temperature and moisture. The temperature measured by each sensor is not equal to the atmospheric temperature due to solar and infrared irradiation of the sensor, heat conduction to the sensor from its attachment points, and radiation emitted by the sensor. Presently, only the RS-80 radiosonde applies corrections to the sensor temperature to compensate for these heating sources, and this correction is only considered to be a function of solar angle and pressure. Temperature correction models VIZCOR (VIZ sonde) and VAICOR (Vaisala RS-80 sonde) have been developed that derive the atmospheric temperature from the sensor temperature, taking into account all significant environmental processes that influence the heat transfer to the sensor. These models have been validated by comparing their corrected profiles with atmospheric temperature profiles derived from the NASA multi-thermistor radiosonde. All three radiosondes were flown on the same balloon during the PREFRS radiosonde intercomparison. Excellent agreement has been found between all profiles up to an altitude of 30 km. Since the significant error sources in the VIZCOR, VAICOR and multi-thermistor techniques are largely independent, agreement between all profiles, implies the corrected sensor profiles are providing an unbiased estimate of the true atmospheric temperature.

Luers, J.K.; Eskridge, R.E.

1994-01-01

24

Interaction corrections at intermediate temperatures: Magnetoresistance in a parallel field  

Microsoft Academic Search

We consider the correction to conductivity of a 2D electron gas due to\\u000aelectron-electron interaction in the parallel magnetic field at arbitrary\\u000arelation between temperature and the elastic mean free time. The correction\\u000aexhibits non-trivial dependence on both temperature and the field. This\\u000adependence is determined by the Fermi liquid constant, which accounts for the\\u000aspin-exchange interaction. In particular, the

Gábor Zala; B. N. Narozhny; I. L. Aleiner

2001-01-01

25

Backscatter correction factor for megavoltage photon beam  

SciTech Connect

Purpose: For routine clinical dosimetry of photon beams, it is often necessary to know the minimum thickness of backscatter phantom material to ensure that full backscatter condition exists. Methods: In case of insufficient backscatter thickness, one can determine the backscatter correction factor, BCF(s,d,t), defined as the ratio of absorbed dose measured on the central-axis of a phantom with backscatter thickness of t to that with full backscatter for square field size s and forward depth d. Measurements were performed in SAD geometry for 6 and 15 MV photon beams using a 0.125 cc thimble chamber for field sizes between 10 x 10 and 30 x 30 cm at depths between d{sub max} (1.5 cm for 6 MV and 3 cm for 15 MV) and 20 cm. Results: A convolution method was used to calculate BCF using Monte-Carlo simulated point-spread kernels generated for clinical photon beams for energies between Co-60 and 24 MV. The convolution calculation agrees with the experimental measurements to within 0.8% with the same physical trend. The value of BCF deviates more from 1 for lower energies and larger field sizes. According to our convolution calculation, the minimum BCF occurs at forward depth d{sub max} and 40 x 40 cm field size, 0.970 for 6 MV and 0.983 for 15 MV. Conclusions: The authors concluded that backscatter thickness is 6.0 cm for 6 MV and 4.0 cm for 15 MV for field size up to 10 x 10 cm when BCF = 0.998. If 4 cm backscatter thickness is used, BCF is 0.997 and 0.983 for field size of 10 x 10 and 40 x 40 cm for 6 MV, and is 0.998 and 0.990 for 10 x 10 and 40 x 40 cm for 15 MV, respectively.

Hu, Yida; Zhu, Timothy C. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

2011-10-15

26

An accurate temperature correction model for thermocouple hygrometers.  

PubMed

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

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

1982-02-01

27

Factors governing tropospheric mean temperature.  

PubMed

Two possible factors, which in addition to Pacific sea surface temperatures might affect the mean temperatures of the tropical troposphere are Atlantic sea surface temperatures and volcanic aerosol. The Mt. Agung eruption in March 1963 produced a decrease of about 0.5 degrees C in the mean temperature of the tropical troposphere. The contribution of the Atlantic is not significant. PMID:17819278

Newell, R E; Weare, B C

1976-12-24

28

Calibration and temperature correction of heat dissipation matric potential sensors  

USGS Publications Warehouse

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

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

2002-01-01

29

Interaction corrections at intermediate temperatures: Longitudinal conductivity and kinetic equation  

Microsoft Academic Search

It is well known that electron-electron interaction in disordered systems\\u000aleads to logarithmically divergent Altshuler-Aronov corrections to conductivity\\u000aat low temperatures ($T\\\\tau\\\\ll 1$; $\\\\tau$ is the elastic mean-free time). This\\u000apaper is devoted to the fate of such corrections at intermediate temperatures\\u000a$T\\\\tau\\\\ge 1$. We show that in this (ballistic) regime the temperature\\u000adependence of conductivity is still governed by

Gábor Zala; B. N. Narozhny; I. L. Aleiner

2001-01-01

30

Power factor correction techniques used for fluorescent lamp ballasts  

Microsoft Academic Search

Various power factor correction techniques used in fluorescent lamp ballast are described. The basic circuit used to control the lamp voltage and current is the current-fed sine wave inverter. Numerous different passive power factor correction circuits were designed, built, and tested. A continuous duty boost converter was designed, built, and tested to make the comparisons. In all cases the wattage

J. Spangler; A. K. Behera

1991-01-01

31

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

32

Pseudophakic correction factors for optical biometry  

Microsoft Academic Search

Introduction: The IOLMaster of Carl Zeiss Jena, which has recently become available, is a combined instrument for biometry and intraocular lens (IOL) planning for cataract surgery utilizing partial coherence interferometry for measuring axial length. Whereas measurement data from classical ultrasound biometry, e.g. in pseudophakic eyes, need to be corrected by +0.4 to -0.8 mm - depending on the lens material

Wolfgang Haigis

2001-01-01

33

Antenna pattern corrections to microwave radiometer temperature calculations  

Microsoft Academic Search

Equations are presented which correct microwave radiometer temperature calculations for the averaging effect of the antenna pattern. Principal plane antenna patterns at 1.43, 4.0, and 7.5 GHz are used to determine the radiometer temperature of a saline water surface. The calculations, made as a function of frequency, polarization, and viewing angle, compare favorably with measured data. The results also show

F. B. Beck

1975-01-01

34

Economic Benefits of Power Factor Correction at a Nuclear Facility.  

National Technical Information Service (NTIS)

The economic benefits of correcting poor power factor at an operating nuclear facility are shown. A project approach for achieving rapid return of investment without disrupting plant availability is described. Examples of technical problems associated wit...

R. M. Boger W. Dalos M. E. Juguilon

1986-01-01

35

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

SciTech Connect

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

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

1993-02-01

36

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

SciTech Connect

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

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

1993-01-01

37

Power Factor Correction Using Magnetic Energy Recovery Current Switches  

NASA Astrophysics Data System (ADS)

In this paper, we propose a Magnetic Energy Recovery Switch (MERS). The switch consists of four MOSFET elements and one capacitor. A power factor improvement is automatically possible regardless of the impedance and power frequency of the load by synchronized switching of MERS with a power supply. MERS itself generates voltage and compensates for the inductance voltage unlike a conventional series capacitor, so that another dc power supply is not needed. An experiment was carried out to demonstrate the automatic correction of the power factor. We can also expect energy saving of electromachies such as an electric motor by the power factor correction with MERS.

Takaku, Taku; Isobe, Takanori; Narushima, Jun; Tsutsui, Hiroaki; Shimada, Ryuichi

38

Cell asymmetry correction for temperature modulated differential scanning calorimetry  

SciTech Connect

The quality of measurement of heat capacity by differential scanning calorimetry (DSC) is based on strict symmetry of the twin calorimeter, which is important for temperature-modulated DSC. Heat capacities for sapphire-filled and empty aluminium calorimeters (pans) under designed cell imbalance caused by different pan-masses were measured. In addition, positive and negative signs of asymmetry were explored by analyzing the phase-shift between temperature and heat flow for sapphire and empty runs. The phase shifts change by more than 18{degree} depending on asymmetry sign. Once the asymmetry sign is determined, the asymmetry correction for modulated DSC can be made.

Ishikiriyama, K.; Wunderlich, B. [Tennessee Univ., Knoxville, TN (United States). Dept. of Chemistry]|[Oak Ridge National Lab., TN (United States)

1996-12-31

39

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

40

Zero current switching cuk converter for power factor correction  

Microsoft Academic Search

A new cuk resonant high power factor single-phase ac to dc converter for power factor correction is proposed in this paper which employs the zero-current switching (ZCS) technique. Merits of the proposed converter include power factor of unity, less harmonic control contents, zero switch loss, simpler control stage, higher power density and unidirectional power flow. Optional principles, design analysis, small-signal

Bor-ren Lin; Tsang-sum Huang

1997-01-01

41

Power factor correction methods applied to piezoelectric actuators  

NASA Astrophysics Data System (ADS)

A study of the application of power factor correction methods to piezoceramic actuators is performed. The power factor is corrected by adding an inductor in both parallel to and in series with the piezoceramic actuator. The actuator consists of two lead zirconate titanate (PZT) patches mounted symmetrically to a cantilever beam. The inductance values were chosen such that each inductor-capacitor (LC) circuit was in resonance at the second natural frequency of the beam. Implementing the parallel LC circuit reduced the current consumption of the piezoceramic actuator by 75 percent when compared to the current consumption of the actuator used without an inductor. Implementing the series LC circuit produced a 300 percent increase in the voltage applied to the actuator compared to the case when no inductor was used. In both cases, employing power factor correction methods corrected the power factor to near unity and reduced the apparent power by 12 dB. A theoretical model of each circuit was developed, and the analytical and empirical results are virtually identical. The results of this study can be used to synthesize circuits to modify piezoceramic actuators, reducing the voltage or current requirements of the amplifiers used to derive those actuators.

Niezrecki, Christopher; Cudney, Harley H.

1993-04-01

42

A fuzzy-power factor correction (abstract only)  

Microsoft Academic Search

Power-factor correction usually means the practice of generating reactive power as close as possible to the load which requires it, rather than supplying it from a remote power station. Most industrial loads have lagging power-factors i.e. they absorb reactive power. The load current, therefore, tends to be larger than is required to supply the real power alone and the excess

Mahmoud A. Manzoul; Venkateshwar B. Rao

1987-01-01

43

Development of a fluorescence internal quenching correction factor to correct botulinum neurotoxin type A endopeptidase kinetics using SNAPtide.  

PubMed

Botulinum neurotoxins (BoNTs), which are highly toxic proteins responsible for botulism, are produced by different strains of Clostridium botulinum. These various strains of bacteria produce seven distinct serotypes, labeled A-G. Once inside cells, the zinc-dependent proteolytic light chain (LC) degrades specific proteins involved in acetylcholine release at neuromuscular junctions causing flaccid paralysis, specifically synaptosomal-associated protein 25 (SNAP-25) for botulinum neurotoxin type A (BoNT/A). BoNT endopeptidase assays using short substrate homologues have been widely used and developed because of their ease of synthesis, detection limits, and cost. SNAPtide, a 13-amino acid fluorescence resonance energy transfer (FRET) peptide, was used in this study as a SNAP-25 homologue for the endopeptidase kinetics study of BoNT/A LC. SNAPtide uses a fluorescein isothiocyanate/4-((4-(dimethylamino)phenyl)azo) benzoic acid (FITC/DABCYL) FRET pair to produce a signal upon substrate cleavage. Signal quenching can become an issue after cleavage since quencher molecules can quench cleaved fluorophore molecules in close proximity, reducing the apparent signal. This reduction in apparent signal provides an inherent error as SNAPtide concentrations are increased. In this study, fluorescence internal quenching (FIQ) correction factors were derived using an unquenched SNAPtide peptide to quantify the signal quenching over a range of SNAPtide concentrations and temperatures. The BoNT/A LC endopeptidase kinetics at the optimally active temperature (37 °C) using SNAPtide were studied and used to demonstrate the FIQ correction factors in this study. The FIQ correction factors developed provide a convenient method to allow for improved accuracy in determining and comparing BoNT/A LC activity and kinetics using SNAPtide over a broad range of concentrations and temperatures. PMID:23181535

Feltrup, Thomas M; Singh, Bal Ram

2012-12-05

44

Translation-rotation correction factor in the theory of homogeneous nucleation  

NASA Astrophysics Data System (ADS)

An analytical formula for the correction factor which is to multiply the classical expression for the nucleation rate to account the translation and rotation of the critical nucleus is proposed. The formula is based on the Reiss approach considering the contribution from the clusters translational degrees of freedom, Frenkel's kinetic theory of liquids, and Kusaka's theory. Using this formula we determined the correction factor for argon vapor-to-liquid phase nucleation for the temperature range 80-110 K. These evaluations are in a good agreement with the correction factor calculated numerically by Kusaka (2006). Basing on the Gibbs theory of capillarity it is also shown that for the case of ideal gas-to-liquid nucleation the exponent in the classical formula for the rate of nucleation is strictly equal to the reversible work of drop formation.

Vosel, S. V.; Onischuk, A. A.; Purtov, P. A.

2009-11-01

45

Gradient corrections to finite-temperature exchange-correlation functionals  

NASA Astrophysics Data System (ADS)

In principle, the only approximation in Kohn-Sham DFT is for the exchange-correlation (XC) energy. As such, about 40 years of development for the zero-temperature XC density functional has resulted in a ladder of functionals from simple LDA (based on essentially exact QMC results) to orbital-dependent functionals including virtuals. The non-zero temperature situation is different. To date, a handful of T 0 K XC functionals have been introduced based on approximate electron gas calculations or interpolations. Except for a finite-T gradient expansion of X, all are local density approximations. Here we present calculations for the XC energy of the electron gas in the dielectric formalism, specifically with approximate local field corrections (LFC). Analysis of the LCF is used to evaluate the first term of the gradient expansion of the XC energy in the slowly varying limit. The resulting gradient expansion finite temperature XC functional will be presented and possible generalized gradient approximations will be considered.

Sjostrom, Travis; Dufty, James

2013-03-01

46

Water-table correction factors applied to gasoline contamination  

Microsoft Academic Search

The application of correction factors to measured ground-water elevations is an important step in the process of characterizing sites contaminated by petroleum products such as gasoline. The water-table configuration exerts a significant control on the migration of free product (e.g., gasoline) and dissolved hydrocarbon constituents. An accurate representation of this configuration cannot be made on the basis of measurements obtained

P. F. Hudak; H. A. Loaiciga; K. M. Clements

2009-01-01

47

Novel compact synchronous rectifier with power factor correction  

Microsoft Academic Search

Sheppard-Taylor(S-T) topology was presented to reduce the output current ripple of DC-DC converters. In this paper, we modified the S-T circuit into AC-DC converter with functions of synchronous rectifier (SR) and power factor correction (PFC). Firstly, we made a comparison between several topologies to show the advantages of AC-DC S-T circuit for our design aim. Then we built up the

Zhao Liang; Zhang Bo; Ma Huasheng

2005-01-01

48

A three-dimensional correction factor equation for deviated wells  

SciTech Connect

The size of a fault cut as determined by log correlation is defined as the true vertical thickness of the missing or repeated section. Likewise, sand thicknesses determined from well logs and used for net sand or net hydrocarbon isopach mapping are also defined in terms of true vertical thickness. Therefore, the size of a fault or the thickness of a sand determined by log correlation with a deviated well, exhibiting a measured log thickness, must be converted to true vertical thickness. The authors have derived a three-dimensional correction factor equation applicable to deviated wells. The equation is used to correct the size of fault cuts for use in fault surface mapping and structure map integration, and the thickness of sand applicable to isopach mapping. This equation is more accurate than any previously published two- or three-dimensional equation. Although two-dimensional equations are simple to use, they lack application in three dimensions. They consider the three-dimensional equation preferable because: (1) this one equation can be used to calculate a correction factor regardless of the direction of wellbore deviation, and (2) the true dip of the beds is used in the equation instead of the apparent dip, which is used in the two-dimensional equations. They introduce a three-dimensional coordinate system, derive the new equation, and illustrate the application of the equation to several deviated wells.

Pousson, H. (Univ. of Southwestern Louisiana, Lafayette (USA)); Tearpock, D.J.

1990-09-01

49

Correction for thermal lag in dynamic temperature measurements using resistance thermometers  

NASA Astrophysics Data System (ADS)

Periodical changes of temperature in the autoclave for the purpose of automatic control are measured with the aid of an encased resistance thermometer. To minimize dynamic errors of this thermometer, two different correcting algorithms have been employed: a known single time-constant one and an algorithm proposed by the authors--two time-constant one. The verification and comparison of the two algorithms was done using a physical model of the autoclave and a real thermometer. Additionally, three methods for the determination of time constants of the second order model were compared and factors influencing the algorithms accuracy, including time constants and sampling time, were analysed. The presented methods make possible to increase both the bandwidth of dynamical temperature measurements and its precision with relatively limited increase in computational complexity of the correction algorithm.

Tomczuk, Krzysztof; Werszko, Radoslaw

2013-07-01

50

Correction for thermal lag in dynamic temperature measurements using resistance thermometers.  

PubMed

Periodical changes of temperature in the autoclave for the purpose of automatic control are measured with the aid of an encased resistance thermometer. To minimize dynamic errors of this thermometer, two different correcting algorithms have been employed: a known single time-constant one and an algorithm proposed by the authors-two time-constant one. The verification and comparison of the two algorithms was done using a physical model of the autoclave and a real thermometer. Additionally, three methods for the determination of time constants of the second order model were compared and factors influencing the algorithms accuracy, including time constants and sampling time, were analysed. The presented methods make possible to increase both the bandwidth of dynamical temperature measurements and its precision with relatively limited increase in computational complexity of the correction algorithm. PMID:23902092

Tomczuk, Krzysztof; Werszko, Radoslaw

2013-07-01

51

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

52

The fallacy of ratio correction to address confounding factors.  

PubMed

Scientists aspire to measure cause and effect. Unfortunately confounding variables, ones that are associated with both the probable cause and the outcome, can lead to an association that is true but potentially misleading. For example, altered body weight is often observed in a gene knockout; however, many other variables, such as lean mass, will also change as the body weight changes. This leaves the researcher asking whether the change in that variable is expected for that change in weight. Ratio correction, which is often referred to as normalization, is a method used commonly to remove the effect of a confounding variable. Although ratio correction is used widely in biological research, it is not the method recommended in the statistical literature to address confounding factors; instead regression methods such as the analysis of covariance (ANCOVA) are proposed. This method examines the difference in means after adjusting for the confounding relationship. Using real data, this manuscript demonstrates how the ratio correction approach is flawed and can result in erroneous calls of significance leading to inappropriate biological conclusions. This arises as some of the underlying assumptions are not met. The manuscript goes on to demonstrate that researchers should use ANCOVA, and discusses how graphical tools can be used readily to judge the robustness of this method. This study is therefore a clear example of why assumption testing is an important component of a study and thus why it is included in the Animal Research: Reporting of In Vivo Experiment (ARRIVE) guidelines. PMID:22829707

Karp, Natasha A; Segonds-Pichon, Anne; Gerdin, Anna-Karin B; Ramírez-Solis, Ramiro; White, Jacqueline K

2012-07-01

53

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. 1065...Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See...emissions for the effects of intake-air humidity or temperature. Use the NOX...

2013-07-01

54

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. 1065...Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See...emissions for the effects of intake-air humidity or temperature. Use the NOX...

2010-07-01

55

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

Code of Federal Regulations, 2010 CFR

...2009-07-01 false NOX intake-air humidity and temperature corrections. 1065...Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See...emissions for the effects of intake-air humidity or temperature. Use the NOX...

2009-07-01

56

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

57

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

PubMed

This paper expands on Archer (J Forensic Sci 49, 2004, 553), examining additional factors affecting ambient temperature correction of weather station data in forensic entomology. Sixteen hypothetical body discovery sites (BDSs) in Victoria and New South Wales (Australia), both in autumn and in summer, were compared to test whether the accuracy of correlation was affected by (i) length of correlation period; (ii) distance between BDS and weather station; and (iii) periodicity of ambient temperature measurements. The accuracy of correlations in data sets from real Victorian and NSW forensic entomology cases was also examined. Correlations increased weather data accuracy in all experiments, but significant differences in accuracy were found only between periodicity treatments. We found that a >5°C difference between average values of body in situ and correlation period weather station data was predictive of correlations that decreased the accuracy of ambient temperatures estimated using correlation. Practitioners should inspect their weather data sets for such differences. PMID:21854385

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

2011-08-19

58

75 FR 72739 - Compliance Testing Procedures: Correction Factor for Room Air Conditioners  

Federal Register 2010, 2011, 2012, 2013

...EERE-2008-BT-TP-0010] Compliance Testing Procedures: Correction Factor for Room Air Conditioners AGENCY...or guidance, to allow use of a data correction factor in compliance testing procedures...reference ``Petition for Rulemaking: Correction Factor for Room Air...

2010-11-26

59

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

Federal Register 2010, 2011, 2012, 2013

...EERE-2008-BT-TP-0010] Compliance Testing Procedures: Correction Factor for Room Air Conditioners AGENCY...guidance, to allow the use of a data correction factor in compliance testing procedures...clothes dryers incorporates use of the correction factor requested in the AHAM...

2011-04-11

60

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

61

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

62

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

Microsoft Academic Search

In this study, we calculated perturbation correction factors for cylindrical ionization chambers in high-energy photon beams\\u000a by using Monte Carlo simulations. We modeled four Farmer-type cylindrical chambers with the EGSnrc\\/Cavity code and calculated\\u000a the cavity or electron fluence correction factor, P\\u000a cav, the displacement correction factor, P\\u000a dis, the wall correction factor, P\\u000a wall, the stem correction factor, P\\u000a stem,

Fumiaki Yoshiyama; Fujio Araki; Takeshi Ono

2010-01-01

63

Radiative Corrections to beta-Decay and Nucleon Form Factors.  

National Technical Information Service (NTIS)

A dispersion theoretical method is used to estimate the radiative correction to the vector part of the beta-decay. The influence of the nucleon structure on the radiative correction is emphasized. An approximation scheme is introduced where contributions ...

G. Kallen

1967-01-01

64

Interaction corrections to the Hall coefficient at intermediate temperatures  

Microsoft Academic Search

We investigate the effect of electron-electron interaction on the temperature\\u000adependence of the Hall coefficient of 2D electron gas at arbitrary relation\\u000abetween the temperature $T$ and the elastic mean-free time $\\\\tau$. At small\\u000atemperature $T\\\\tau \\\\ll \\\\hbar$ we reproduce the known relation between the\\u000alogarithmic temperature dependences of the Hall coefficient and of the\\u000alongitudinal conductivity. At higher temperatures,

Gábor Zala; B. N. Narozhny; I. L. Aleiner

2001-01-01

65

An EGSnrc investigation of the P{sub TP} correction factor for ion chambers in kilovoltage x rays  

SciTech Connect

As part of the standard practice for obtaining consistent ion chamber measurements with cavities open to the surrounding atmosphere, the raw measured response is corrected to the response at a reference temperature and pressure using the standard temperature-pressure correction factor (P{sub TP}). In this study, the EGSnrc Monte Carlo code was used to investigate the validity of the P{sub TP} correction factor for kilovoltage x rays incident on various geometrically distinct ion chambers. The calculated P{sub TP}-corrected chamber response deviated by over 2% relative to expected values for a 40 kV spectrum incident on a graphite thimble chamber at an air density typical of Mexico City. The relative deviation from the expected response was much worse for a large spherical graphite chamber, exceeding 16% at an air density of 0.6 kg/m{sup 3} ({approx_equal}0.5 atm at 22 deg. C) for the same beam energy. The breakdown of the P{sub TP} correction factor was also observed for a 26 kV mammography spectrum incident on two mammography chambers. For {sup 60}Co beams, the P{sub TP} correction factor behaved as expected. For day-to-day variations in pressure, only a negligible of the P{sub TP} correction factor was observed with low x-ray energies. Factors contributing to the breakdown of the P{sub TP} correction factor at low x-ray energies and large pressure variations, such as the range of electrons, the material of the wall, the chamber dimensions and air-photon interactions, are discussed in depth.

La Russa, Daniel J.; Rogers, D. W. O. [Carleton Laboratory for Radiotherapy Physics, Ottawa-Carleton Institute for Physics, Carleton University, Ottawa, ON, K1S 5B6 (Canada)

2006-12-15

66

Power Factor Correction of Single-Phase Induction Motor Using Magnetic Energy Recovery Switch  

Microsoft Academic Search

Magnetic energy recovery switch (MERS) has a function of automatic power factor correction of series connected load. The MERS is applied for a single-phase induction motor to improve the power factor. Two control methods of the MERS for power factor correction are described in this paper. Experiments were carried out and confirmed that the input power factor of a single-phase

Taku Takaku; Jun Narushima; Takanori Isobe; Tadayuki Kitahara; Ryuichi Shimada

2006-01-01

67

Note: Vignetting calibration and temperature correction for casting billets.  

PubMed

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

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

2013-09-01

68

Note: Vignetting calibration and temperature correction for casting billets  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

69

Permeability correction factor for fractures with permeable walls  

NASA Astrophysics Data System (ADS)

Enhanced Geothermal Systems (EGS) are based on the premise that heat can be extracted from hot dry rocks located at significant depths by circulating fluid through fracture networks in the system. Heated fluid is recovered through production wells and the energy is extracted in a heat exchange chamber. There is much published research on flow through fractures, and many models have been developed to describe an effective permeability of a fracture or a fracture network. In these cases however, the walls of the fracture were modelled as being impermeable. In this paper, we have extended our previous work on fractures with permeable walls, and we introduce a correction factor to the equation that governs fracture permeability. The solution shows that the effective fracture permeability for fractures with permeable walls depends not only on the height of the channel, but also on the wall permeability and the wall Reynolds number of the fluid. We show that our solution reduces to the established solution when the fracture walls become impermeable. We also extend the discussion to cover the effective permeability of a system of fractures with permeable walls.

Mohais, R.; Xu, C.; Dowd, P. A.; Hand, M.

2012-02-01

70

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

SciTech Connect

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

Li Hsiangnan [Institute of Physics, Academia Sinica, Taipei, Taiwan 115 (China); Department of Physics, National Cheng-Kung University, Tainan, Taiwan 701 (China); Department of Physics, National Tsing-Hua University, Hsinchu, Taiwan 300 (China); Shen Yuelong [Institute of Physics, Academia Sinica, Taipei, Taiwan 115 (China); College of Information Science and Engineering, Ocean University of China, Qingdao, Shandong 266100 (China); Wang Yuming [Theoretische Physik 1, Fachbereich Physik, Universitaet Siegen, D-57068 Siegen (Germany); Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Post Office Box 918 (4) Beijing 100049 (China); Zou Hao [Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Post Office Box 918(4) Beijing 100049 (China)

2011-03-01

71

Correcting the Cenozoic ?18O deep-sea temperature record  

Microsoft Academic Search

The oxygen isotope signal in benthic foraminifera from deep-sea cores is mainly determined by deep-ocean temperature and\\u000aland ice volume. Separating the temperature and ice volume signals is a key step in understanding the evolution of Cenozoic\\u000aclimate. Except for the last few million years, fluctuations in land ice volume were determined mainly by the size of the\\u000aAntarctic ice

J. Oerlemans

2004-01-01

72

Urban-Effect Correction to Improve Accuracy of Spatially Interpolated Temperature Estimates in Korea  

Microsoft Academic Search

Gridded temperature data are frequently used to run ecological models at regional scales and are routinely generated by spatially interpolating point observations at synoptic weather stations. If synoptic stations are located in urbanized areas, observed temperature and the interpolated data could be contaminated by the urban heat island effect. Without an appropriate correction, temperature estimates over rural areas or forests

Jaeyeon Choi; Uran Chung; Jin I. Yun

2003-01-01

73

The surface-brightness method and the dependence of the bolometric correction on star effective temperature  

Microsoft Academic Search

Studies of the physical characteristics of 228 stars (Tef > 4700K) are used to plot the surface-brightness parameter against the (B-V)0 and (V-R)0 color indices (corrected for interstellar reddening) and the bolometric correction against effective temperature. Simple analytic expressions are derived for these relationships.

A. N. Gubochkin; A. S. Miroshnichenko

1991-01-01

74

The surface-brightness method and the dependence of the bolometric correction on star effective temperature.  

NASA Astrophysics Data System (ADS)

Studies of the physical characteristics of 228 stars (Tef > 4700K) are used to plot the surface-brightness parameter against the (B-V)0 and (V-R)0 color indices (corrected for interstellar reddening) and the bolometric correction against effective temperature. Simple analytic expressions are derived for these relationships.

Gubochkin, A. N.; Miroshnichenko, A. S.

75

Factors affecting body temperatures of toads  

Microsoft Academic Search

Factors influencing levels and rates of variation of body temperature (Tb) in montane Bufo boreas boreas and in lowland Bufo boreas halophilus were investigated as an initial step toward understanding the role of natural thermal variation in the physiology and energetics of these ectothermic animals. Body temperatures of boreas can vary 25–30° C over 24-h periods. Such variation is primarily

Cynthia Carey

1978-01-01

76

Dry Snow Temperature Gradient Metamorphism: Is Our Picture Correct?  

NASA Astrophysics Data System (ADS)

Temperature gradient metamorphism (TGM) was the subject of many studies in the past 100 years. However, a direct observation of the transport phenomena was impossible, since an observation automatically destroyed the sample. Using 4D micro-tomography, we could observe the evolution of structures in situ under temperature gradients. Combining the time-lapse tomography with microscopic temperature and concentration field modeling, the temporal evolution of heat and mass transport can be calculated and visualized. We found that the prevailing concept of larger grains growing on the expense of smaller ones is wrong under temperature gradient conditions. Instead, the whole ice matrix is continuously replaced by sublimation and deposition. The slow average growth of the structures is caused by population dynamics: larger structures have a longer residence time than smaller ones (Fig. 1). This observation solves one of the larger mysteries of snow metamorphism, namely why the diffusion coefficient (Deff) of water vapor should be much higher than in air (Yosida et al, Cont. Inst. Low. Temp. Sci, 7:19-74 1955). Our measurements and simulations show that Deff is not enhanced, but is the same as in air. This was already suspected by Giddings and LaChapelle (JGR, 67:2377-2383,1962), as they interpreted the results of Yosida as an experimental artifact. Later models seem to have overlooked this interpretation, and are based on an incorrect quasi one-dimensional arrangement of ice spheres. The fundamental and dominating process during TGM is therefore vapor diffusion, and the intensity dictated by the temperature gradient. Our measurements of mass flux show that the vapor flux on a macroscopic scale is independent of the microstructure. The development of future snow simulation models incorporating changes in microstructure not based on empirical observations, but on effective vapor mass flux, will now be feasible. The picture of snow metamorphism is much more dynamic than anticipated, and our results may also improve the understanding of chemical processes within snow. Figure 1: Residence time of ice matrix in a depth hoar structure after 27 days at a temperature gradient of 50 K m -1. The oldest ice is younger than 200 h.

Schneebeli, M.; Pinzer, B. R.; Kaempfer, T. U.

2009-12-01

77

Bias Corrections for Historical Sea Surface Temperatures Based on Marine Air Temperatures  

Microsoft Academic Search

Because of changes in SST sampling methods in the 1940s and earlier, there are biases in the earlier period SSTs relative to the most recent 50 years. Published results from the Met Office have shown the need for historic bias correction and have developed several correction techniques. An independent bias-correction method is developed here from an analysis using nighttime marine

Thomas M. Smith; Richard W. Reynolds

2002-01-01

78

Corrections.  

PubMed

In the report "Distribution and detection of positrons from an orbiting nuclear reactor" by E. W. Hones and P. R. Higbie (28 Apr., p. 448), the following corrections should be noted. The first sentence of the caption for figure 1 should have read, "Location of SMM (dots) and Cosmos 1176 (triangles) at the times of 21 of the most intense 511-keV gamma events recorded by SMM during the 29 April to 2 September 1980 operating period." The first sentence of the caption for figure 3 should have read, "Estimated differential energy spectrum positrons escaping from Cosmos 1176 per joule of fission energy." On page 450, the second sentence of the first full paragraph should have referred to event 5, not event 59. PMID:17820653

1989-06-16

79

Absorbed dose dependence of the correction factors for ionization chamber cable irradiation effects.  

PubMed

A simple method was developed, for possible use by hospital physicists, to evaluate the irradiation effects on cables and connectors during large-radiation-field dosimetry with ionization chambers and to determine correction factors for the used system or geometry. This method was based on the absorbed dose dependence of the correction factor. PMID:2038606

Campos, L L; Caldas, L V

1991-03-01

80

Novel current transducer in a single-phase active power factor correction system  

Microsoft Academic Search

In line-fed converters implementing power factor correction, the current shaping process requires input current sensing, commonly obtained using dedicated power components as shunts or current transformers. This work presents a current sensing circuit applied to active power factor correction with boost topology, which does not use the previous components. The sensing element is an inductor placed in the input filter,

Enrico Dallago; Marco Passoni; Gabriele Sassone; Giuseppe Venchi

2000-01-01

81

Recombinant factor VIIa corrects prothrombin time in cirrhotic patients: A preliminary study  

Microsoft Academic Search

BACKGROUND & AIMS: Cirrhotic patients with a prolonged prothrombin time (PT) are known to have low levels of factor VII. Because the current modalities to correct this problem are not ideal, recombinant factor VIIa (rFVIIa) may be useful in correcting the prolonged PT observed in the coagulopathy of cirrhosis. The aim of this study was to evaluate the effectiveness of

DE Bernstein; L Jeffers; E Erhardtsen; KR Reddy; S Glazer; P Squiban; R Bech; U Hedner; ER Schiff

1997-01-01

82

Gamma ray self attenuation correction factor study. Final report  

SciTech Connect

The overall focus of this work was an attempt to better understand the nature of self attenuating particles of SNM for the purpose of developing procedures for correcting for particle self attenuation relative to improving the quantitative non-destructive assay of these materials. This report is a summary of the various schemes, calculations, data and data analysis performed relative to this subject.

NONE

1993-04-14

83

Power Factor Correction of Single-Phase Induction Motor Using Magnetic Energy Recovery Switch  

NASA Astrophysics Data System (ADS)

Magnetic energy recovery switch (MERS) has a function of automatic power factor correction of series connected load. The MERS is applied for a single-phase induction motor to improve the power factor. Two control methods of the MERS for power factor correction are described in this paper. Experiments were carried out and confirmed that the input power factor of a single-phase induction motor is improved.

Takaku, Taku; Narushima, Jun; Isobe, Takanori; Kitahara, Tadayuki; Shimada, Ryuichi

84

TOPEX\\/Poseidon Microwave Radiometer (TMR). II. Antenna pattern correction and brightness temperature algorithm  

Microsoft Academic Search

For pt.I see ibid., vol.33, no.1, p.125-37 (1995). The calibrated antenna temperatures measured by the TOPEX Microwave Radiometer are used to derive radiometric brightness temperatures in the vicinity of the altimeter footprint. The basis for the procedure devised to do this-the antenna pattern correction and brightness temperature algorithm-is described in the paper, along with its associated uncertainties. The algorithm is

Michael A. Janssen; Christopher S. Ruf; Stephen J. Keihm

1995-01-01

85

Application of a Raman distributed temperature sensor to the experimental fast reactor JOYO with correction techniques  

Microsoft Academic Search

In order to apply a Raman distributed temperature sensor (RDTS) to the monitoring of nuclear facilities, some correction techniques for radiation-induced errors were developed and investigated. One is a simple correction technique with two thermocouples, when uniform radiation-induced loss distribution can be assumed. The other is a special technique with a loop-type arrangement. In this technique, even when the loss

Atsushi Kimura; Eiji Takada; Kaoru Fujita; Masaharu Nakazawa; Hiroyuki Takahashi; Satoshi Ichige

2001-01-01

86

The effect of ambient pressure on well chamber response: experimental results with empirical correction factors.  

PubMed

For some air-communicating well-type chambers used for low-energy brachytherapy source assay, deviations from expected values of measured air kerma strength were observed at low pressures associated with high altitudes. This effect is consistent with an overcompensation by the air density correction to standard atmospheric temperature and pressure (P(TP)). This work demonstrates that the P(TP) correction does not fully compensate for the high altitude pressure effects that are seen with air-communicating chambers at low photon energies in the range of 20-100 keV. Deviations of up to 18% at a pressure corresponding to an approximate elevation of 8500 ft for photon energies of 20 keV are possible. For high-energy photons and for high-energy beta emitters in air-communicating chambers the P(TP) factor is applicable. As expected, the ambient pressure does not significantly affect the response of pressurized well chambers (within 1%) to either low- or high-energy photons. However, when used with beta emitters, pressurized chambers appear to exhibit a slight dependence on the ambient pressure. Using measured data, the response and correction factors were determined for three models of air-communicating well chambers for low-energy photon sources at various pressures corresponding to elevations above sea level. Monte Carlo calculations were also performed which were correlated with the experimental findings. A more complete study of the Monte Carlo calculations is presented in the accompanying paper, "The effect of ambient pressure on well chamber response: Monte Carlo calculated results for the HDR1000 Plus." PMID:15839341

Griffin, S L; DeWerd, L A; Micka, J A; Bohm, T D

2005-03-01

87

Energy dependence of correction factors for the Victoreen Model 666 Portable Radiographic Health Survey System.  

PubMed

The energy dependence for each of three models of Victoreen 666 ionization chambers is characterized through an examination of the correction factors determined over the diagnostic x-ray range (0.4-4.9 mm A1 HVL) for many samples of each model. The results of an analysis of variance performed for each chamber model on the correction factors are reported as mean correction factors for the x-ray beams evaluated, with a relative standard error of less than 0.6% in all cases. Energy-dependence curves for the three chamber models are given, and their use is described. PMID:904596

Morgan Brateman, L; Dirkse, J

88

Temperature corrections to the thermodynamic functions of a degenerate neutron gas in a magnetic field  

SciTech Connect

Temperature corrections to the basic thermodynamic functions calculated in our earlier publication for a degenerate neutron gas in a magnetic field are determined taking into account the anomalous magnetic moment of a neutron. The heat capacity and entropy of the degenerate neutron gas, as well as the temperature correction to the magnetic susceptibility, are also calculated. Additional arguments supporting the effect of an increase in the pulse frequency of pulsars mentioned in the previous publication are formulated; the results of that publication are refined.

Skobelev, V. V., E-mail: v.skopbelev@inbox.ru [Moscow State Industrial University (Russian Federation)

2011-08-15

89

A New High-precision Correction Method of Temperature Distribution in Model Stellar Atmospheres  

NASA Astrophysics Data System (ADS)

The main features of the temperature correction methods, suggested and used in modeling of plane-parallel stellar atmospheres, are discussed. The main features of the new method are described. Derivation of the formulae for a version of the Unsöld-Lucy method, used by us in the SMART (Stellar Model Atmospheres and Radiative Transport) software for modeling stellar atmospheres, is presented. The method is based on a correction of the model temperature distribution based on minimizing differences of flux from its accepted constant value and on the requirement of the lack of its gradient, meaning that local source and sink terms of radiation must be equal. The final relative flux constancy obtainable by the method with the SMART code turned out to have the precision of the order of 0.5 %. Some of the rapidly converging iteration steps can be useful before starting the high-precision model correction. The corrections of both the flux value and of its gradient, like in Unsöld-Lucy method, are unavoidably needed to obtain high-precision flux constancy. A new temperature correction method to obtain high-precision flux constancy for plane-parallel LTE model stellar atmospheres is proposed and studied. The non-linear optimization is carried out by the least squares, in which the Levenberg-Marquardt correction method and thereafter additional correction by the Broyden iteration loop were applied. Small finite differences of temperature (? T/T=10-3) are used in the computations. A single Jacobian step appears to be mostly sufficient to get flux constancy of the order 10-2 %. The dual numbers and their generalization -- the dual complex numbers (the duplex numbers) -- enable automatically to get the derivatives in the nilpotent part of the dual numbers. A version of the SMART software is in the stage of refactorization to dual and duplex numbers, what enables to get rid of the finite differences, as an additional source of lowering precision of the computed results.

Sapar, A.; Poolamäe, R.; Sapar, L.

90

Improving solar ultraviolet irradiance measurements by applying a temperature correction method for Teflon diffusers  

NASA Astrophysics Data System (ADS)

To establish trends in surface ultraviolet radiation levels, accurate and stable long-term measurements are required. The accuracy level of today's measurements has become high enough to notice even smaller effects that influence instrument sensitivity. Laboratory measurements of the sensitivity of the entrance optics have shown a decrease of as much as 0.07-0.1%/deg temperature increase. Since the entrance optics can heat to greater than 45 °C in Dutch summers, corrections are necessary. A method is developed to estimate the entrance optics temperatures from pyranometer measurements and meteorological data. The method enables us to correct historic data records for which temperature information is not available. The temperature retrieval method has an uncertainty of less than 2.5 °C, resulting in a 0.3% uncertainty in the correction to be performed. The temperature correction improves the agreement between modeled and measured doses and instrument intercomparison as performed within the Quality Assurance of Spectral Ultraviolet Measurements in Europe project. The retrieval method is easily transferable to other instruments.

Jäkel, Evelyn; den Outer, Peter N.; Tax, Rick B.; Görts, Peter C.; Reinen, Henk A. J. M.

2007-07-01

91

LIGHT-DUTY DIESEL EMISSION CORRECTION FACTORS FOR AMBIENT CONDITIONS  

EPA Science Inventory

Since emission measurements from passenger cars are performed at one standard set of ambient conditions and since emission rates of HC, CO, and NOx are sensitive to temperature and humidity, it is necessary to determine the influence of ambient conditions on emissions from major ...

92

Angular dependence of the wall correction factor for air kerma measurements using cylindrical cavity chambers  

Microsoft Academic Search

The dependence of the results of air kerma measurements on the orientation of the cylindrical cavity chamber used for beam standardizations is reexamined. The wall attenuation correction factors for the 60Co and 136Cs air kerma measurements were obtained for various irradiation angles by extrapolation of the dependences of experimental data and by Monte Carlo simulations. Applying the correction based on

Tadahiro Kurosawa; Nobuhisa Takata; Yasuji Koyama

2005-01-01

93

Correction improves z-factor values for high gas density  

Microsoft Academic Search

A simple modification is suggested to improve the z-factor values obtained from the subroutines developed from the Dranchuk, et al., and Abou-Kassem equations of state. These correlations are commonly included in some software available for general use in the petroleum industry. The original subroutines, proposed by these authors, return inaccurate values for high gas density within the application range stated

1991-01-01

94

Fibroblast Growth Factor 21 Corrects Obesity in Mice  

Microsoft Academic Search

Fibroblast growth factor 21 (FGF21) is a metabolic regulator that provides efficient and durable glycemic and lipid control in various animal models. However, its potential to treat obe- sity, a major health concern affecting over 30% of the popu- lation, has not been fully explored. Here we report that sys- temic administration of FGF21 for 2 wk in diet-induced obese

Tamer Coskun; Holly A. Bina; Michael A. Schneider; James D. Dunbar; Charlie C. Hu; Yanyun Chen; David E. Moller; Alexei Kharitonenkov

2008-01-01

95

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

National Technical Information Service (NTIS)

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 configurati...

T. F. Regan E. J. Lewandowski J. G. Schreiber

2007-01-01

96

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

97

Area detector corrections for high quality synchrotron X-ray structure factor measurements  

SciTech Connect

Correction procedures for obtaining accurate X-ray structure factors from large area detectors are considered, including subpanel effects, over excited pixels and careful intensity corrections. Problems associated with data normalization, the use of a pixel response correction from a glass standard and minimization of systematic errors are also discussed. Data from glassy GeSe{sub 2} and liquid water measured with a Perkin Elmer amorphous-Silicon detector are used to demonstrate the effectiveness of these correction procedures. This requires reduction of systematic errors in the measured intensity to around the 0.1% level.

Skinner L. B.; Parise J.; Benmore, C.

2011-10-01

98

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

99

Power-factor-corrected single-stage inductive charger for electric-vehicle batteries  

Microsoft Academic Search

A novel power-factor-corrected single-stage AC-DC converter for inductive charging of electric vehicle batteries is introduced. The resonant converter uses the current-source characteristic of the series-parallel topology to provide power factor correction over a wide output power range from zero to full load. Some design guidelines for this converter are outlined. An approximate small-signal model of the converter is also presented

D. O'Sullivan; M. Willers; M. G. Egan; J. G. Hayes; P. T. Nguyen; C. P. Henze

2000-01-01

100

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

Microsoft Academic Search

The aim of the study was to evaluate the perturbation correction factors at a reference depth for cylindrical ionization chambers\\u000a in high-energy electron beams by means of the EGSnrc Monte Carlo user code cavity. The cylindrical chambers used in this study\\u000a were the Farmer-type of PTW30010, PTW30011, PTW30012, and PTW30013 models. We calculated the wall correction factor, P\\u000a wall, the

Takeshi Ono; Fujio Araki; Fumiaki Yoshiyama

2010-01-01

101

The surface-brightness method and the dependence of bolometric correction on stellar effective temperature  

Microsoft Academic Search

Relationships between the surface-brightness parameter and dereddened color indices (B-V)0 and (V-R)0, as well as between the bolometric correction and the effective temperature, are constructed using data on the physical characteristics of 228 stars with Teff greater than 4700 K. Simple analytical expressions are obtained for these relationships.

A. N. Gubochkin; A. S. Miroshnichenko

1991-01-01

102

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...

103

Transformations from Theoretical Hertzsprung-Russell Diagrams to Color-Magnitude Diagrams: Effective Temperatures, BV Colors, and Bolometric Corrections  

Microsoft Academic Search

This paper provides improved numerical relations between effective temperatures of stars, their B - V colors, and their bolometric corrections (B Cs) for the purpose of comparing theoretical stellar evolutionary calculations to color-magnitude diagrams of star clusters. Temperatures and bolometric correction measurements for 335 stars from the literature form the observational basis for the transformations. Measured temperatures range from 2900

Phillip J. Flower

1996-01-01

104

Elevation correction of ERA-Interim temperature data in complex terrain  

NASA Astrophysics Data System (ADS)

Air temperature controls a large variety of environmental processes, and is an essential input parameter for land surface models, for example in hydrology, ecology and climatology. However, meteorological networks, which can provide the necessary information, are commonly sparse in complex terrains, especially in high mountainous regions. In order to provide temperature data in an adequate temporal and spatial resolution for local scale applications a new elevation correction method has been developed that is able to downscale 3-hourly ERA-Interim temperature data. The scheme is based on model internal vertical lapse rates derived from different ERA-Interim pressure levels and has been validated for twelve meteorological stations in the German and Swiss Alps. The method was also compared with two other statistical, lapse rate based correction approaches. The results indicate that the use of model internal ERA-Interim lapse rates can significantly improve the downscaling performance when compared to the standard procedure of using fixed lapse rates.

Gao, L.; Bernhardt, M.; Schulz, K.

2012-12-01

105

Communication: The effect of dispersion corrections on the melting temperature of liquid water  

NASA Astrophysics Data System (ADS)

The melting temperature (Tm) of liquid water with the Becke-Lee-Yang-Parr (BLYP) density functional including dispersion corrections (BLYP-D) and the Thole-type, version 3 (TTM3-F) ab-initio based flexible, polarizable classical potential is reported via constant pressure and constant enthalpy (NPH) molecular dynamics simulations of an ice Ih-liquid coexisting system. Dispersion corrections to BLYP lower Tm to about 360 K, a large improvement over the value of Tm > 400 K previously obtained with the original BLYP functional under the same simulation conditions. For TTM3-F, Tm = 248 K from classical molecular dynamics simulations.

Yoo, Soohaeng; Xantheas, Sotiris S.

2011-03-01

106

The determination of beam quality correction factors: Monte Carlo simulations and measurements  

NASA Astrophysics Data System (ADS)

Modern dosimetry protocols are based on the use of ionization chambers provided with a calibration factor in terms of absorbed dose to water. The basic formula to determine the absorbed dose at a user's beam contains the well-known beam quality correction factor that is required whenever the quality of radiation used at calibration differs from that of the user's radiation. The dosimetry protocols describe the whole ionization chamber calibration procedure and include tabulated beam quality correction factors which refer to 60Co gamma radiation used as calibration quality. They have been calculated for a series of ionization chambers and radiation qualities based on formulae, which are also described in the protocols. In the case of high-energy photon beams, the relative standard uncertainty of the beam quality correction factor is estimated to amount to 1%. In the present work, two alternative methods to determine beam quality correction factors are prescribed—Monte Carlo simulation using the EGSnrc system and an experimental method based on a comparison with a reference chamber. Both Monte Carlo calculations and ratio measurements were carried out for nine chambers at several radiation beams. Four chamber types are not included in the current dosimetry protocols. Beam quality corrections for the reference chamber at two beam qualities were also measured using a calorimeter at a PTB Primary Standards Dosimetry Laboratory. Good agreement between the Monte Carlo calculated (1% uncertainty) and measured (0.5% uncertainty) beam quality correction factors was obtained. Based on these results we propose that beam quality correction factors can be generated both by measurements and by the Monte Carlo simulations with an uncertainty at least comparable to that given in current dosimetry protocols.

González-Castaño, D. M.; Hartmann, G. H.; Sánchez-Doblado, F.; Gómez, F.; Kapsch, R.-P.; Pena, J.; Capote, R.

2009-08-01

107

Three-Phase Boost Active Power Factor Correction for Diode Rectifiers.  

National Technical Information Service (NTIS)

This report documents an investigation and implementation of a 3 kW active power factor correction (pfc) design used to enable a diode rectifier to draw sinusoidal line currents with nearly unity power factor from a three-phase utility grid. The design ut...

J. G. Nairus

1996-01-01

108

A novel charge pump power factor correction electronic ballast for high intensity discharge lamps  

Microsoft Academic Search

A new charge pump power factor correction electronic ballast for high intensity discharge lamps is proposed in this paper. The concept and operation principle of the ballast circuit are first derived. The design guideline for the charge pump capacitors is discussed. The proposed electronic ballast is implemented and tested. No flicker, more than 0.95 power factor and less than 20%

T. Yamauchi; T. Shiomi

1998-01-01

109

A low-cost four-switch BLDC motor drive with active power factor correction  

Microsoft Academic Search

This paper presents a high-performance low-cost brushless DC (BLDC) motor drive for commercial and residential applications. The proposed drive employs fewer number of switches than the conventional converter and incorporates an active power factor correction feature which results in sinusoidal input current at close to unity power factor. The proposed converter has bidirectional capability, which improves speed control features of

S. M. Madani; Lei Hao; H. A. Toliyat

2002-01-01

110

Capacitive power factor and power quality correction of a light rail transportation system  

Microsoft Academic Search

This paper discusses an application of a method for dynamic power factor correction and voltage regulation in light rail transportation systems. The MV underground power cables installed for the distribution of 34.5 kV power substations cause a very poor capacitive reactive power factor. The technical specification of the customer was based on the dynamic compensation of the consumed electrical energy

U. Celtekligil

2008-01-01

111

Analytical Solutions for Static Shear Correction Factor of Functionally Graded Rectangular Beams  

Microsoft Academic Search

Most practical analyses of functionally graded beams, particularly in aerospace, aircraft, automobile and civil structures, are based on first order shear deformation theory. However, a key factor in practical application of the theory is determination of the transverse shear correction factor, which appears as a coefficient in the expression for the transverse shear stress resultant. The physical basis for this

Rabha Menaa; Abdelouahed Tounsi; Fethi Mouaici; Ismail Mechab; Mohamed Zidi; El Abbas Adda Bedia

2012-01-01

112

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

SciTech Connect

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

Eides, Michael I.; Shelyuto, Valery A. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States); D. I. Mendeleev Institute of Metrology, St. Petersburg 190005 (Russian Federation)

2009-09-01

113

Correcting temperature and humidity forecasts using Kalman filtering: potential for agricultural protection in Northern Greece  

NASA Astrophysics Data System (ADS)

A correction method for the provision of accurate near-surface temperature and humidity forecasts is developed, based on the combination of a Kalman theory filtering technique and an empirical method with exponential smoothing. The combined method is applied on high-resolution weather forecasts provided by an operational model in Greece, over a basin in the northern part of the country, where agricultural protection is of great importance, especially due to mildew in potatoes, which represents a constant threat for farmers. The application of the method has shown that it can substantially reduce errors of the near-surface temperature and humidity forecasts provided for 2-3 days ahead in time. Based on these corrected forecasts, farmers can then schedule their fungicide spraying programs according to the expected weather, thus reducing the cost and the ecological impact of frequent preventive spraying interventions.

Anadranistakis, Manolis; Lagouvardos, Kostas; Kotroni, Vassiliki; Elefteriadis, Helias

114

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

PubMed Central

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

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

2012-01-01

115

Impact of the neutron detector choice on Bell and Glasstone spatial correction factor for subcriticality measurement  

NASA Astrophysics Data System (ADS)

In subcritical assemblies, the Bell and Glasstone spatial correction factor is used to correct the measured reactivity from different detector positions. In addition to the measuring position, several other parameters affect the correction factor: the detector material, the detector size, and the energy–angle distribution of source neutrons. The effective multiplication factor calculated by computer codes in criticality mode slightly differs from the average value obtained from the measurements in the different experimental channels of the subcritical assembly, which are corrected by the Bell and Glasstone spatial correction factor. Generally, this difference is due to (1) neutron counting errors; (2) geometrical imperfections, which are not simulated in the calculational model, and (3) quantities and distributions of material impurities, which are missing from the material definitions.This work examines these issues and it focuses on the detector choice and the calculation methodologies. The work investigated the YALINA Booster subcritical assembly of Belarus, which has been operated with three different fuel enrichments in the fast zone either: high (90%) and medium (36%), medium (36%), or low (21%) enriched uranium fuel.

Talamo, Alberto; Gohar, Y.; Cao, Y.; Zhong, Z.; Kiyavitskaya, H.; Bournos, V.; Fokov, Y.; Routkovskaya, C.

2012-03-01

116

Target mass corrections for spin-dependent structure functions in collinear factorization  

SciTech Connect

We derive target mass corrections (TMC) for the spin-dependent nucleon g_1 and g_2 structure functions in collinear factorization at leading twist. The TMCs are found to be significant for g_1 at large x_B, even at relatively high Q^2 values, but largely cancel in the polarization asymmetry A_1. A comparison of TMCs obtained from collinear factorization and from the operator product expansion shows that at low Q^2 the corrections drive the proton A_1 in opposite directions.

Accardi, Alberto; Melnitchouk, Wolodymyr

2008-12-01

117

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

118

Shear Correction Factors in Creep-Damage Analysis of Beams, Plates and Shells  

NASA Astrophysics Data System (ADS)

Modern design rules for thin-walled structures which operate at elevated temperatures are based on the demand that the creep and may be the damage behaviour should be taken into account. In the last four decades various models including the scalar or tensor valued hardening and damage variables are established. These models reflect the influence of the deformation or the damage induced anisotropy on the creep response. One problem in creep analysis of thin-walled structures is the selection of the structural mechanics model which has to be adequate to the choice of the constitutive equations. Considering complex loading conditions the structural mechanics model has to reflect for instance the different constitutive behaviour in tension and compression. Below the applicability of classical engineering models for beams, plates and shells to the creep-damage analysis is discussed. It will be shown that a first improvement of the classical approach can be given within the assumptions of the first order shear deformation theory. Based on the beam equations we demonstrate that the shear correction factors have to be modified within the time-step analysis.

Altenbach, Holm; Naumenko, Konstantin

119

Temperature and nonlinearity corrections for a photodiode array spectrometer used in the field  

SciTech Connect

Temperature and nonlinearity effects are two important factors that limit the use of photodiode array spectrometers. Usually the spectrometer is calibrated at a known temperature against a reference source of a particular spectral radiance, and then it is used at different temperatures to measure sources of different spectral radiances. These factors are expected to be problematic for nontemperature-stabilized instruments used for in-the-field experiments, where the radiant power of the site changes continuously with the sun tilt. This paper describes the effect of ambient temperature on a nontemperature-stabilized linear photodiode array spectrometer over the temperature range from 5 deg. C to 40 deg. C. The nonlinearity effects on both signal amplification and different levels of radiant power have also been studied and are presented in this paper.

Salim, Saber G. R.; Fox, Nigel P.; Theocharous, Evangelos; Sun, Tong; Grattan, Kenneth T. V.

2011-02-20

120

Right-handed neutrino production at finite temperature: radiative corrections, soft and collinear divergences  

NASA Astrophysics Data System (ADS)

The production and decay rate of massive sterile neutrinos at finite temperature receives next-to-leading order corrections from the gauge interactions of lepton and Higgs doublets. Using the Closed-Time-Path approach, we demonstrate that the perturbatively obtained inclusive rate is finite. For this purpose, we show that soft, collinear and Bose divergences cancel when adding the tree-level rates from 1 ? 3 and 2 ? 2 processes to vertex and wave-function corrections to 1 ? 2 processes. These results hold for a general momentum of the sterile neutrino with respect to the plasma frame. Moreover, they do not rely on non-relativistic approximations, such that the full quantum-statistical effects are accounted for to the given order in perturbation theory. While the neutrino production rate is of relevance for Leptogenesis, the proposed methods may as well be suitable for application to a more general class of relativistic transport phenomena.

Garbrecht, Björn; Glowna, Frank; Herranen, Matti

2013-04-01

121

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

122

A physics-based correction model for homogenizing sub-daily temperature series  

NASA Astrophysics Data System (ADS)

A new physics-based technique for correcting inhomogeneities present in sub-daily temperature records is proposed. The approach accounts for changes in the sensor-shield characteristics that affect the energy balance dependent on ambient weather conditions (radiation, wind). An empirical model is formulated that reflects the main atmospheric processes and can be used in the correction step of a homogenization procedure. The model accounts for short- and long-wave radiation fluxes (including a snow cover component for albedo calculation) of a measurement system, such as a radiation shield. One part of the flux is further modulated by ventilation. The model requires only cloud cover and wind speed for each day, but detailed site-specific information is necessary. The final model has three free parameters, one of which is a constant offset. The three parameters can be determined, e.g., using the mean offsets for three observation times. The model is developed using the example of the change from the Wild screen to the Stevenson screen in the temperature record of Basel, Switzerland, in 1966. It is evaluated based on parallel measurements of both systems during a sub-period at this location, which were discovered during the writing of this paper. The model can be used in the correction step of homogenization to distribute a known mean step-size to every single measurement, thus providing a reasonable alternative correction procedure for high-resolution historical climate series. It also constitutes an error model, which may be applied, e.g., in data assimilation approaches.

Auchmann, R.; BröNnimann, S.

2012-09-01

123

Power factor correction system by means of continuous modulation. Final report.  

National Technical Information Service (NTIS)

The novel power factor correction system described is an improvement over existing ones because it reduces the VAR's with no switching transients, continuously; i.e., without the customary VAR-jumps that result from the usual capacitor-switchings. In the ...

Z. Zabar N. Kaish

1997-01-01

124

A Simple Design Method for Nonlinear Control of Power Factor Correction Boost Converter  

Microsoft Academic Search

A simple design method for power factor correction (PFC) boost converter is presented in this article. Model based cascade controller design is presented for the control of PFC boost converters. Detail discussions in the setting of bandwidth for the current loop and voltage loop have been given. Finally, a deadband relay is introduced in the voltage loop to improve the

K. M. Tsang; W. L. Chan

2006-01-01

125

Development of a fuzzy logic controller for boost rectifier with active power factor correction  

Microsoft Academic Search

This paper presents the use of fuzzy logic to derive a practical control scheme for a boost rectifier with active power factor correction. The methodology integrates a fuzzy logic control technique in the feedback path and linear programming rule on controlling the duty cycle of the switch for shaping the input current waveform. The proposed approach avoids complexities associated with

Henry S. H. Chung; Eugene P. W. Tam; S. Y. R. Hui

1999-01-01

126

High power factor correction circuits with space vector and hysteresis control methods  

Microsoft Academic Search

This paper presents a new topology of the three-phase ac to dc converter. Only three ac switches are required to perform the power factor correction. The series connection of the two output capacitors is adapted to employ the high dc output voltage. A space vector modulation strategy is used to control two of the three ac switches at any time,

Bor-Ren Lin; Deng-Ping Wu

1997-01-01

127

Boost Rectifier Power Factor Correction Circuits with Improved Harmonic and Load Voltage Regulation Responses  

Microsoft Academic Search

The time domain step response for rapid load changes can be improved in boost type power factor correction circuits by using a capacitor voltage model. In single phase PFC circuits, the dc bus voltage must have a significant voltage ripple at twice the mains frequency due to energy balance requirements. In traditional implementations, the presence of this ripple voltage causes

Peter Wolfs; Peter Thomas

2007-01-01

128

Theory of the brush-shifting AC Motor - III power-factor correction  

Microsoft Academic Search

In the preceding papers1 of this series a method was described for determining the circle diagram and predicting the characteristics for the brush-shifting motor as it is used when the brushes are shifted to control speed. This paper extends the earlier work to show how the motor can be used to correct power factor. The range and limitations for this

A. G. Conrad; F. Zweig; J. G. Clarke

1942-01-01

129

Variations in mutual coupling correction factors for resonant dipoles used in site attenuation measurements  

Microsoft Academic Search

Site attenuation measurements using resonant dipole antennas are commonly used to certify test sites for compliance testing to the Federal Communication Commission Part 15 requirements. Mutual coupling has previously been shown to affect the impedance of resonant dipole antennas. It is pointed out that a correction factor must be added to ANS C63.4 normalized site attenuation for these measurements to

John Berry; Barry Pate; Alan Knight

1990-01-01

130

Tetralogy of fallot: Factors influencing the mortality rate of total correction  

Microsoft Academic Search

ROM 1957 TO THE PRESENT, a total of 215 patients with tetralogy of Fallot underwent operations for total correction using extracorporeal circu- lation. Although the overall mortality rate was about 13 per cent. the rate de- creased considerably during the 10 years. The most significant factors influ- encing the mortality rate were found to be the age of the patient

Sathaporn Vathayanon; Donald R. Kahn; Aaron M. Stern; Joan M. Sigmann; Park W. Willis III; Burton L. Perry; Marvin M. Kirsh; Pauline W. Ferguson; Herbert Sloan

1968-01-01

131

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

Microsoft Academic Search

The authors of a recent paper (Wang and Rogers 2009 Phys. Med. Biol. 54 1609) have used the Monte Carlo method to simulate the 'classical' experiment made more than 30 years ago by Johansson et al (1978 National and International Standardization of Radiation Dosimetry (Atlanta 1977) vol 2 (Vienna: IAEA) pp 243-70) on the displacement (or replacement) perturbation correction factor

Pedro Andreo

2010-01-01

132

Correction factor to dye-measured flow velocity under varying water and sediment discharges  

Technology Transfer Automated Retrieval System (TEKTRAN)

Dye-tracing technique was a widely used method to measure velocity of overland flow in soil erosion studies under both laboratory and field conditions. Few studies were performed to quantify the effects of sediment load on correction factor on steep slopes. The objective was to investigate the poten...

133

A new power-factor-correction circuit for electronic ballasts with series-load resonant inverter  

Microsoft Academic Search

This paper presents an efficient, small-sized and cost-effective power factor correction (PFC) scheme for high-frequency series-resonant electronic ballasts. The proposed scheme introduces additional small energy tanks processing partial power and thus can perform the function of input current shaping. Theoretical and experimental results prove that the electronic ballast incorporating with only few reactive components can achieve nearly unity power factor

Chin S. Moo; Ying C. Chuang; Ching R. Lee

1998-01-01

134

Calculations of electron fluence correction factors using the Monte Carlo code PENELOPE  

Microsoft Academic Search

In electron-beam dosimetry, plastic phantom materials may be used instead of water for the determination of absorbed dose to water. A correction factor ?waterplastic is then needed for converting the electron fluence in the plastic phantom to the fluence at an equivalent depth in water. The recommended values for this factor given by AAPM TG-25 (1991 Med. Phys.18 73–109) and

E A Siegbahn; B Nilsson; J M Fernández-Varea; P Andreo

2003-01-01

135

A novel single-phase power-factor-corrected voltage regulator  

Microsoft Academic Search

This paper presents a new single-phase power-factor-corrected (PFC) AC\\/DC voltage regulator using a parallel power processing scheme. By combining a PFC cell and a DC\\/DC cell into a new power converter structure, higher conversion efficiency than those of the conventional cascaded configurations can be achieved while maintaining good power factor and fast output voltage regulation. Moreover, the storage capacitor voltage

D. D. C. Lu; D. K. W. Cheng; Y. S. Lee

2001-01-01

136

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

137

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

2012-05-01

138

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

139

Finite temperature corrections to the Casimir effect in rectangular cavities with perfectly conducting walls  

NASA Astrophysics Data System (ADS)

The thermodynamical properties of a quantized electromagnetic field inside a box with perfectly conducting walls are studied using a regularization scheme that permits to obtain finite expressions for the thermodynamic potentials. The source of ultraviolet divergences is directly isolated in the expression for the density of modes, and the logarithmic infrared divergences are regularized imposing the uniqueness of vacuum and, consequently, the vanishing of the entropy in the limit of zero temperature. We thus obtain corrections to the Casimir energy and pressures, and to the specific heat; these results suggest effects that could be tested experimentally.

Jáuregui, R.; Villarreal, C.; Hacyan, S.

2006-09-01

140

Comparisons between various width fluctuation correction factors for compound nucleus reactions  

NASA Astrophysics Data System (ADS)

The exact expression for the width fluctuation correction factor, obtained with the Gaussian orthogonal ensemble (GOE) approach, has been implemented computationally to describe a nuclear reaction for any open channel-elastic, inelastic, capture, and fission. This exact expression is compared with various approximate expressions. It turns out that the approximate expression given by Moldauer is the closest to the GOE value. Since comparison between model predictions and experimental data alone cannot provide the answer concerning the correct approximate method, the present comparison indicates that Moldauer's model is the one to use in reaction models for practical applications.

Hilaire, S.; Lagrange, Ch.; Koning, A. J.

2003-08-01

141

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

SciTech Connect

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

Eides, M. I., E-mail: eides@pa.uky.ed [University of Kentucky, Department of Physics and Astronomy (United States); Shelyuto, V. A., E-mail: shelyuto@vniim.r [Mendeleev Institute of Metrology (Russian Federation)

2010-01-15

142

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

DOEpatents

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

Kustra, T.A.; Cafferal, A.J.

1988-08-29

143

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

DOEpatents

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

Kustra, Thomas A. (N. Huntingdon, PA); Caffarel, Alfred J. (Pittsburgh, PA)

1990-01-01

144

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

2013-03-21

145

Universal Binding and Recoil Corrections to Bound State g Factors in Hydrogenlike Ions  

SciTech Connect

The leading relativistic and recoil corrections to bound state g factors of particles with arbitrary spin are calculated. It is shown that these corrections are universal for any spin and depend only on the free particle gyromagnetic ratios. To prove this universality we develop nonrelativistic quantum electrodynamics (NRQED) for charged particles with an arbitrary spin. The coefficients in the NRQED Hamiltonian for higher spin particles are determined only by the requirements of Lorentz invariance and local charge conservation in the respective relativistic theory. For spin one charged particles, the NRQED Hamiltonian follows from the renormalizable QED of the charged vector bosons. We show that universality of the leading relativistic and recoil corrections can be explained with the help of the Bargmann-Michael-Telegdi equation.

Eides, Michael I.; Martin, Timothy J. S. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States)

2010-09-03

146

Errors in climate model daily precipitation and temperature output: time invariance and implications for bias correction  

NASA Astrophysics Data System (ADS)

When correcting for biases in general circulation model (GCM) output, for example when statistically downscaling for regional and local impacts studies, a common assumption is that the GCM biases can be characterized by comparing model simulations and observations for a historical period. We demonstrate some complications in this assumption, with GCM biases varying between mean and extreme values and for different sets of historical years. Daily precipitation and maximum and minimum temperature from late 20th century simulations by four GCMs over the United States were compared to gridded observations. Using random years from the historical record we select a "base" set and a 10-yr independent "projected" set. We compare differences in biases between these sets at median and extreme percentiles. On average a base set with as few as 4 randomly-selected years is often adequate to characterize the biases in daily GCM precipitation and temperature, at both median and extreme values; 12 yr provided higher confidence that bias correction would be successful. This suggests that some of the GCM bias is time invariant. When characterizing bias with a set of consecutive years, the set must be long enough to accommodate regional low frequency variability, since the bias also exhibits this variability. Newer climate models included in the Intergovernmental Panel on Climate Change fifth assessment will allow extending this study for a longer observational period and to finer scales.

Maurer, E. P.; Das, T.; Cayan, D. R.

2013-02-01

147

Factor Analysis of Coastal Air Pressure and Water Temperature  

Microsoft Academic Search

From an examination of the rotated factors produced by common factor analysis, a relationship between water temperatures measured at Blunt's Reef Light Ship and air pressure measured at Eureka, Calif., was isolated. Also water temperatures recorded at both Trinidad Head and Blunt's Reef were quite different as evidenced by differences in factor loadings. Furthermore, the magnitudes of the correlation coefficients

Gerald Hannes

1976-01-01

148

Stress Intensity Factor Plasticity Correction for Flaws in Stress Concentration Regions  

SciTech Connect

Plasticity corrections to elastically computed stress intensity factors are often included in brittle fracture evaluation procedures. These corrections are based on the existence of a plastic zone in the vicinity of the crack tip. Such a plastic zone correction is included in the flaw evaluation procedure of Appendix A to Section XI of the ASME Boiler and Pressure Vessel Code. Plasticity effects from the results of elastic and elastic-plastic explicit flaw finite element analyses are examined for various size cracks emanating from the root of a notch in a panel and for cracks located at fillet fadii. The results of these caluclations provide conditions under which the crack-tip plastic zone correction based on the Irwin plastic zone size overestimates the plasticity effect for crack-like flaws embedded in stress concentration regions in which the elastically computed stress exceeds the yield strength of the material. A failure assessment diagram (FAD) curve is employed to graphically c haracterize the effect of plasticity on the crack driving force. The Option 1 FAD curve of the Level 3 advanced fracture assessment procedure of British Standard PD 6493:1991, adjusted for stress concentration effects by a term that is a function of the applied load and the ratio of the local radius of curvature at the flaw location to the flaw depth, provides a satisfactory bound to all the FAD curves derived from the explicit flaw finite element calculations. The adjusted FAD curve is a less restrictive plasticity correction than the plastic zone correction of Section XI for flaws embedded in plastic zones at geometric stress concentrators. This enables unnecessary conservatism to be removed from flaw evaluation procedures that utilize plasticity corrections.

Friedman, E.; Wilson, W.K.

2000-02-01

149

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.

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

150

Current-source charge-pump power-factor-correction electronic ballast  

SciTech Connect

A current-source charge-pump power-factor-correction (CS-CPPFC) electronic ballast is presented in this paper. Unity-power-factor condition and principle of operation using the CP concept are derived and analyzed. Based on the steady-state analysis, the design considerations are discussed in detail. It is shown that the power switch only deals with the resonant load current, which is the same as in the two-stage approach so that small-current rating devices can be used. The developed CS-CPPFC electronic ballast can save one inductor and has a potentially low cost. The CS-CP electronic ballast with switching frequency modulation to improve crest factor is developed, implemented, and tested. It is shown that 0.99 power factor, 11.3% total harmonic distortion (THD), and 1.54 crest factor can be achieved for 85-W fluorescent lamps.

Qian, J.; Lee, F.C.Y. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Yamauchi, Tokushi [Matsushita Electric Works, Inc., Woburn, MA (United States)

1998-05-01

151

A method to correct satellite measurements of sea surface temperature for the effects of atmospheric aerosols  

NASA Astrophysics Data System (ADS)

Multichannel sea surface temperature (MCSST) measurements with the NOAA 7 advanced very high resolution radiometer (AVHRR) have been corrected for the effects of the El Chichon aerosol layer by using a previously developed method of inferring the aerosol optical thickness (?) from the channel 1 radiance. A theoretical model shows that the error in the MCSST is directly proportional to ? sec ?, where ? is the satellite zenith angle. Data using moored buoy SST's and AVHRR MCSST's at five locations verify this relationship. Analysis of the data also shows empirically that the MCSST error is more closely related to ln (? sec2?). Linear regressions for these relationships for the combined data of two locations show correlation coefficients of 0.80 and 0.88 for the ?sec ? and ln (? sec2?) relationships, respectively. These regression lines are used to correct the MCSST values in the independent data sets of the other three locations. Statistics of the comparison between the corrected MCSST's and the buoy SST's show that the root mean square difference in the MCSST and buoy SST comparison is 1.14°C and 1.01°C for the ?sec ? and ln (?sec2?) relationships, respectively. These values are close to the value of 1.05°C found in an extensive study at NOAA of an earlier MCSST algorithm that was not influenced by aerosols. Before this correction, considerable daytime data were rejected by the MCSST algorithm, and errors as large as 7°C were observed. It appears that the correction procedure can be used in the presence of partial cloud in a pixel, since both the MCSST and the aerosol algorithms interpret the partial cloud as a uniform haze. Thus the technique also results in the retrieval of more MCSST values (than are currently available with the NOAA cloud filter tests) in the presence of clouds in normal aerosol conditions. The technique also offers the potential of increasing the accuracy of MCSST measurements in normal atmospheres where the aerosols are mostly in the troposphere.

Griggs, M.

1985-12-01

152

Parallel Type Voltage Sag Compensator with Reduced Capacitor by Boost Type Power Factor Correction Rectifier  

NASA Astrophysics Data System (ADS)

A new circuit of parallel type voltage sag compensator is proposed in this paper. The proposed voltage sag compensator can reduce the necessary capacity of the energy storage capacitor for compensation by boost type power factor correction rectifier charging the capacitor during a voltage sag. As a result the proposed system can reduce the size and maintenances of the apparatus. This paper shows principle and control system of the proposed circuit. Compensation characteristics were demonstrated by simulation and experiment.

Kojima, Tetsuya; Takauchi, Toshihiko; Ise, Toshifumi; Iyoda, Isao; Kono, Yoshiyuki; Temma, Koji; Sasao, Hiroyuki; Yamasaki, Kiyomi; Inoue, Nobuyoshi; Takeuchi, Yasunori

153

An On-Line UPS System With Power Factor Correction and Electric Isolation Using BIFRED Converter  

Microsoft Academic Search

This paper presents the design consideration and performance analysis of an on-line, low-cost, high performance, and single-phase uninterruptible power supply (UPS) system based on a boost integrated flyback rectifier\\/energy storage dc\\/dc (BIFRED) converter. The system consists of an isolated ac\\/dc BIFRED converter, a bidirectional dc\\/dc converter, and a dc\\/ac inverter. It provides input power factor correction, electric isolation of the

Adel Nasiri; Zhong Nie; Stoyan B. Bekiarov; Ali Emadi

2008-01-01

154

An on-line UPS system with power factor correction and electric isolation using BIFRED converter  

Microsoft Academic Search

This paper presents design consideration and performance analysis of an on-line, low-cost, high performance single-phase Uninterruptible Power Supply (UPS) system based on Boost Integrated Flyback Rectifier\\/Energy storage DC\\/DC (BIFRED) converter. The system consists of an isolated AC\\/DC BIFRED converter, a bi-directional DC\\/DC converter, and a DC\\/AC inverter. It has input power factor correction, electric isolation of the input from the

Z. Nie; S. B. Bekiarov; A. Emadi

2003-01-01

155

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

NASA Astrophysics Data System (ADS)

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

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

156

Design of one-cycle control power factor correction IC with unipolar supply voltage  

Microsoft Academic Search

A one-cycle control based constant frequency operating trailing-edge continuous conduction mode (CCM) boost type power factor correction (PFC) IC with instant-switch-current control is proposed. By using a level shift circuit, this PFC controller can be operated using unipolar supply voltage. Moreover, the functions of leading edge blanking (LEB) and over voltage protection (OVP) are integrated into the proposed IC to

Kai-Chi Chang; Kai-Hui Chen; Tsorng-Juu Liang; Bin-Da Liu

2009-01-01

157

Improved radiative corrections and proton charge form factor from the Rosenbluth separation technique  

SciTech Connect

We investigate whether the apparent discrepancy between proton electric form factors from measurements using the Rosenbluth separation technique and those obtained with the polarization transfer method is attributable to the standard approximations employed in radiative correction procedures. Inaccuracies attributable to both the peaking approximation and the soft-photon approximation have been removed in our simulation approach. In contrast to results from (e,e{sup '}p) experiments, we find those in this case to be too small to explain the discrepancy.

Weissbach, Florian [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt D-64291 (Germany); Departement fuer Physik, Universitaet Basel, Basel CH-4056 (Switzerland); Hencken, Kai [Departement fuer Physik, Universitaet Basel, Basel CH-4056 (Switzerland); ABB Switzerland Ltd., Corporate Research, Baden-Daettwil CH-5405 (Switzerland); Trautmann, Dirk; Sick, Ingo [Departement fuer Physik, Universitaet Basel, Basel CH-4056 (Switzerland)

2009-12-15

158

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

159

Laminated glass beams: Strength factor and temperature effect  

Microsoft Academic Search

Glass design charts are available for annealed, monolithic glasses. In order to use these design charts, strength of a laminated glass unit needs to be adjusted by a strength factor. This paper presents a study on strength factor and the effect of various factors on the strength factor, like ambient temperature, width and length of the beam. The effect of

Mehmet Zülfü A??k; Selim Tezcan

2006-01-01

160

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

NASA Astrophysics Data System (ADS)

Context. Precise and accurate determinations of the atmospheric parameters effective temperature and surface gravity are mandatory to derive reliable chemical abundances in OB stars. Furthermore, fundamental parameters like distances, masses, radii, luminosities can also be derived from the temperature and gravity of the stars. Aims: Atmospheric parameters recently determined at high precision with several independent spectroscopic indicators in non-local thermodynamic equilibrium, with typical uncertainties of ~300 K for temperature and of ~0.05 dex for gravity, are employed to calibrate photometric relationships. This is in order to investigate whether a faster tool to estimate atmospheric parameters can be provided. Methods: Temperatures and gravities of 30 calibrators, i.e. well-studied OB main sequence to giant stars in the solar neighbourhood, are compared to reddening-independent quantities of the Johnson and Strömgren photometric systems, assuming normal reddening. In addition, we examine the spectral and luminosity classification of the star sample and compute bolometric corrections. Results: Calibrations of temperatures and gravities are proposed for various photometric indices and spectral types. Once the luminosity of the stars is well known, effective temperatures can be determined at a precision of ~400 K for luminosity classes III/IV and ~800 K for luminosity class V. Furthermore, surface gravities can reach internal uncertainties as low as ~0.08 dex when using our calibration to the Johnson Q-parameter. Similar precision is achieved for gravities derived from the ?-index and the precision is lower for both atmospheric parameters when using the Strömgren indices [c1] and [u - b] . In contrast, external uncertainties are larger for the Johnson than for the Strömgren calibrations. Our uncertainties are smaller than typical differences among other methods in the literature, reaching values up to ± 2000 K for temperature and ± 0.25 dex for gravity, and in extreme cases, + 6000 K and ± 0.4 dex, respectively. A parameter calibration for sub-spectral types is also proposed. Moreover, we present a new bolometric correction relation to temperature based on our empirical data, rather than on synthetic grids. Conclusions: The photometric calibrations presented here are useful tools to estimate effective temperatures and surface gravities of non-supergiant OB stars in a fast manner. This is also applicable to some single-line spectroscopic binaries, but caution has to be taken for undetected double-lined spectroscopic binaries and single objects with anomalous reddening-law, dubious photometric quantities and/or luminosity classes, for which the systematic uncertainties may increase significantly. We recommend to use these calibrations only as a first step of the parameter estimation, with subsequent refinements based on spectroscopy. A larger sample covering more uniformly the parameter space under consideration will allow refinements to the present calibrations. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max- Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC), proposals H2001-2.2-011 and H2005-2.2-016.Based on observations collected at the European Southern Observatory, Chile, ESO 074.B-0455(A) and from the ESO Archive.Based on spectral data retrieved from the ELODIE archive at Observatoire de Haute-Provence (OHP).Appendices A and B are available in electronic form at http://www.aanda.org

Nieva, M.-F.

2013-02-01

161

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

NASA Astrophysics Data System (ADS)

Having been in use at Hohenpeissenberg from 1781-1841, the Palatina thermometer was found to suffer from a positive bias of 0.5°R (or 0.63°C) as discovered by Lamont following a re-calibration made in 1842. The main reason was due to the composition of the glass used during the early instrumental period. Glass of this period tended to contract over many years due to thermal aftereffects, resulting in a gradual rise of the freezing point position in consequence of the shrinking bulb forming the mercury reservoir. While the problem of the gradually rising zero point was recognised relatively early, the reason was attributed to wrong causes. Around 1880, scientists recognised that the chemical composition of glass might be responsible for the drift of the zero point. New glass types were developed which were free from such effects. Although these facts became known, no correction was applied to the Hohenpeissenberg temperature series when in 1981, the complete 200-year series was published. Most probably this bias is also relevant for other stations, at least those of the network of the Societas Meteorologica Palatina that were supplied with thermometers manufactured in Mannheim. Another problem originates from the different observing times for the period 1879-1900, which were set to 0800, 1400 and 2000 hours instead of 0700, 1400 and 2100 hours before and afterwards. In addition, a new formula to calculate the daily mean was established resulting in the temperature being too low by 0.5°C in that period. The overall trend changes after application of the two necessary corrections. There remain two biases that cannot be quantified without a major detailed study being made: (1) At the start of the observations, the window of the observation room was always kept “open during dry weather”. It is not known how long this practice was remained in use. (2) Lamont also employed an easily melting glass to construct his thermometers which in use between 1841 and 1878. An analysis of the glass composition seems to be necessary to find out whether it also suffered from a rising freezing point. Lamont replaced the Hohenpeissenberg thermometer in 1842 by a new instrument produced in his own workshop. One still existing Lamont thermometer, but not that one of Hohenpeissenberg, was re-calibrated and the zero point found to have lowered by -1.4°C. Since the opposite drift had been expected and the original Lamont-type Hohenpeissenberg thermometer is no longer available, no correction is justified for the period in which this thermometer was in use.

Winkler, P.

2009-10-01

162

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

163

Vibration Behavior of Composite Beams with Rectangular Sections Considering the Different Shear Correction Factors  

NASA Astrophysics Data System (ADS)

As is well known, there are the first and higher order shear deformation theories that involve the shear correction factor (k- factor), which appears as a coefficient in the expression for the transverse shear stress resultant, to consider the shear deformation effects with a good approximation as a result of non-uniform distribution of the shear stresses over the cross-section of the beam. Timoshenko's beam theory (TBT) accounts both the shear and rotatory inertia effects based upon the first order shear deformation theory which offers the simple and acceptable solutions. The numerical value of the k-factor which was originally proposed by Timoshenko depends upon generally both the Poisson's ratio of the material and the shape of the cross-section. Recently, especially the numerical value of the k-factor for rectangular sections is examined by both theoretical and experimental manners. Although there are no large numerical differences among the most of the theories, a few of them says that the k-factor varies obviously with the aspect ratio of rectangular sections while Timoshenko's k-factor is applicable for small aspect ratios. In this study, the effect of the different k-factors developed by Timoshenko, Cowper and Hutchinson on the in-plane free vibration of the orthotropic beams with different boundary conditions and different aspect ratios are studied numerically based on the transfer matrix method. For the first six frequencies, the relative differences of among the theories are presented by charts.

Y?ld?r?m, Vebil

164

Energy dependence of correction factors for some Victoreen Model 570 Condensor R-Meter medium-energy chambers.  

PubMed

The energy dependence of each of six models of medium-energy Victoreen 570 Condenser R-Meter chambers was determined by measurement of the exposure correction factors over the diagnostic x-ray beam-quality range (0.4-4.1 mm A1 HVL) for several samples of each model. The results of an analysis of variance performed by model on the correction factors are reported as mean correction factors for the x-ray beams evaluated, with a relative standard error less than 0.8% in all cases. Energy-dependence curves for the six chamber models are given; their use is described. PMID:904597

Morgan, T J; Brateman, L; Dirkse, J

165

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

SciTech Connect

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

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

2012-01-01

166

Two-loop QED corrections with closed fermion loops for the bound-electron g factor  

NASA Astrophysics Data System (ADS)

Two-loop QED corrections with closed fermion loops are calculated for the 1s bound-electron g factor. Calculations are performed to all orders in the nuclear binding strength parameter Z? (where Z is the nuclear charge and ? is the fine-structure constant) except for the closed fermion loop, which is treated within the free-loop (Uehling) approximation in some cases. Comparison with previous Z?-expansion calculations is made and the higher-order remainder of order ?2(Z?)5 and higher is separated out from the numerical results.

Yerokhin, V. A.; Harman, Z.

2013-10-01

167

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

168

Toward improved corrections for radiation-induced biases in radiosonde temperature observations  

NASA Astrophysics Data System (ADS)

biases in global operational radiosonde temperature data from May 2008 to August 2011 are examined by using spatially and temporally collocated Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) data as estimates of the truth. The data on average from most radiosonde types show a nighttime cold bias and a daytime warm bias relative to COSMIC. Most daytime biases increase with altitude and solar elevation angle (SEA). The global average biases in the 15-70 hPa layer are -0.05 ± 1.89 K standard deviation (~52,000 profiles) at night and 0.39 ± 1.80 K standard deviation (~64,500 profiles) in daytime (SEA > 7.5°). Daytime warm biases associated with clouds are smaller than those under clear conditions. Newer sondes (post-2000) have smaller biases and appear to be less sensitive to effects of clouds. Biases at night show greater seasonal and zonal variations than those for daytime. In general, warm night biases are associated with warm climate regimes and less warm or cold night biases with cold climate regimes. Bias characteristics for 13 major radiosonde types are provided, as a basis for updating radiosonde corrections used in numerical weather predictions, for validating satellite retrievals, and for adjusting archived radiosonde data to create consistent climate records.

Sun, Bomin; Reale, Anthony; Schroeder, Steven; Seidel, Dian J.; Ballish, Bradley

2013-05-01

169

Evaluation of correction factors for transmittance measurements in single-beam integrating spheres.  

PubMed

An integrating sphere for transmittance measurements at normal and oblique angles of incidence has been constructed. The sphere is a single-beam instrument that uses a small-area silicon diode as the detector. The entry port is only 0.37% of the total wall area and has an oblong shape to permit measurements at high angles of incidence for scattering samples. A small beam size has been made possible by using a low-noise preamplifier system for the detector circuit. The oblong port shape and a small beam size make it possible to perform simulated double-beam measurements at near-normal incidence. Modified correction factors for the sample reflectance have been derived. Special attention has been paid to the separation into a diffuse and a specular component of the transmitted light. Results have been compared with the results of measurements on a double-beam instrument, and the correction factors for specular and diffuse samples have been experimentally verified. The importance of using the right correctionfactors for different types of samples has been evaluated together with the influence of the sphere parameters. PMID:20936027

Grandin, K; Roos, A

1994-09-01

170

Application of geometry correction factors for low-level waste package dose measurements. Revision 1  

SciTech Connect

Plans are to determine the Cs-137 content of low-level waste packages generated in High-Level Waste by measuring the radiation level at a specified distance from the package with a hand-held radiation instrument. The measurement taken at this specified distance, either 3 or 5 feet, is called the far-field measurement. This report documents a method for adjusting the gamma exposure rate (mR/hr) reading used in dose-to-curie determinations when the far-field measurement equals the background reading. This adjustment is necessary to reduce the conservatism resulting from using a minimum detection limit exposure rate for the dose-to-curie determination for the far-field measurement position. To accomplish this adjustment, the near-field (5 cm) measurement is multiplied by a geometry correction factor to obtain an estimate of the far field exposure rate (which is below instrument sensitivity). This estimate of the far field exposure rate is used to estimate the Cs-137 curie content of the package. This report establishes the geometry correction factors for the dose-to-curie determination when the far-field gamma exposure measurement equals the background reading. This report also provides a means of demonstrating compliance to 1S Manual requirements for exposure rate readings at different locations from waste packages while specifying only two measurement positions. This demonstration of compliance is necessary to minimize the number of locations exposure rate measurements that are required, i.e., ALARA.

Chandler, M.C.; Parish, B.

1995-01-05

171

Stress, Temperature, Heart Rate, and Hibernating Factors in Hamsters.  

National Technical Information Service (NTIS)

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 appl...

X. J. Musacchia

1974-01-01

172

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

Microsoft Academic Search

Purpose--Low perturbation diodes, with thin buildup caps, can be used to reduce perturbations to the delivered dose. The literature states that additional correction factors are required for low perturbation diodes, however, there are few reported studies into their use. This report measured the dose perturbations and correction factors for diodes with varying buildup cap thicknesses. Methods and materials--Scanditronix EDP15, EDD5,

Ralph Roberts; Amanda Philp

2008-01-01

173

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

174

Research on temperature calibration of extended area blackbody based on two-point multi-section linear correction algorithm  

NASA Astrophysics Data System (ADS)

The spectral radiation of extended area blackbody source is widely used to provide a reference for absolute temperature in infrared test and calibration. Thus the temperature accuracy of extended area blackbody is a critical parameter to determine the performance of test and calibration system. The temperature of emissive surface is measured and controlled by Platinum resistance temperature sensor. A variety of techniques have been developed for improving the temperature accuracy of extended area blackbody. In order to overcome nonlinear error caused by the Platinum resistance temperature sensor, a calibration method based on two-point multi-section linear correction algorithm is proposed. The tests verify that the method enhances the calibration accuracy of temperature accuracy of extended area blackbody and satisfies the requirements of high precision tests on metrological quality.

Han, Shun-li; Hu, Wei-liang; Luo, Wen-jian; Wang, Rui-xia

2013-08-01

175

Correction Techniques of Radiation Induced Errors for Raman Distributed Temperature Sensor and Experiment at the Experimental Fast Reactor: JOYO  

Microsoft Academic Search

Optical fibers have advantages like flexible configuration, intrinsic immunity for electromagnetic fields etc., and they have been used as optical fiber sensors. By some of these techniques, continuous or discrete distribution of physical parameters can be measured. Here, in order to apply Raman distributed temperature sensor (RDTS) to the monitoring of nuclear facilities: some correction techniques for radiation induced errors

Eiji TAKADA; Atsushi KIMURA; Fredrik B. H. JENSEN; Masaharu NAKAZAWA

1998-01-01

176

Enhanced conduction-corrected modified effective temperature as the outdoor thermal environment evaluation index upon the human body  

Microsoft Academic Search

This paper aims to clarify the handling technique of the solar radiation in an element of the thermal environment evaluation indices and to add expansions and improvements to conduction-corrected modified effective temperature ETF (Kurazumi et al., 2009) that can quantify the comprehensive effect on sensational and physiological sense and the effect of individual meteorological elements on the same evaluation axis applicable

Yoshihito Kurazumi; Kenta Fukagawa; Yoshiaki Yamato; Kunihito Tobita; Emi Kondo; Tadahiro Tsuchikawa; Tetsumi Horikoshi; Naoki Matsubara

2011-01-01

177

Monte Carlo study of correction factors for the use of plastic phantoms in clinical electron dosimetry  

SciTech Connect

In some recent dosimetry protocols, plastic is allowed as a phantom material for the determination of an absorbed dose to water in electron beams, especially for low energy with beam qualities R{sub 50}<4 g/cm{sup 2}. In electron dosimetry with plastic, a depth-scaling factor, c{sub pl}, and a chamber-dependent fluence correction factor, h{sub pl}, are needed to convert the dose measured at a water-equivalent reference depth in plastic to a dose at a reference depth in water. The purpose of this study is to calculate correction factors for the use of plastic phantoms for clinical electron dosimetry using the EGSnrc Monte Carlo code system. RMI-457 and WE-211 were investigated as phantom materials. First the c{sub pl} values for plastic materials were calculated as a function of a half-value depth of maximum ionization, I{sub 50}, in plastic. The c{sub pl} values for RMI-457 and WE-211 varied from 0.992 to 1.002 and from 0.971 to 0.979, respectively, in a range of nominal energies from 4 MeV to 18 MeV, and varied slightly as a function of I{sub 50} in plastic. Since h{sub pl} values depend on the wall correction factor, P{sub wall}, of the chamber used, they are evaluated using a pure electron fluence correction factor, {phi}{sub pl}{sup w}, and P{sub wall}{sup w} and P{sub wall}{sup pl} for a combination of water or plastic phantoms and plane-parallel ionization chambers (NACP-02, Markus and Roos). The {phi}{sub pl}{sup w} and P{sub wall} (P{sub wall}{sup w} and P{sub wall}{sup pl}) values were calculated as a function of the water-equivalent depth in plastic materials and at a reference depth as a function of R{sub 50} in water, respectively. The {phi}{sub pl}{sup w} values varied from 1.024 at 4 MeV to 1.013 at 18 MeV for RMI-457, and from 1.025 to 1.016 for WE-211. P{sub wall}{sup w} values for plane-parallel chambers showed values in the order of 1.5% to 2% larger than unity at 4 MeV, consistent with earlier results. The P{sub wall}{sup pl} values of RMI-457 and WE-211 were close to unity for all the energy beams. Finally, calculated h{sub pl} values of RMI-457 ranged from 1.009 to 1.005, from 1.010 to 1.003 and from 1.011 to 1.007 for NACP-02, Markus and Roos chambers, respectively, in the range of 4 MeV to 18 MeV, and the values of WE-211 were 1.010 to 1.004, 1.010 to 1.004 and 1.012 to 1.008, respectively. The calculated h{sub pl} values for the Markus chamber agreed within their combined uncertainty with the measured data.

Araki, Fujio [Department of Radiological Technology, Kumamoto University School of Health Sciences, 4-24-1, Kuhonji, Kumamoto, 862-0976 (Japan)

2007-11-15

178

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

179

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

2010-12-07

180

Calculated energy response correction factors for LiF thermoluminescent dosemeters employed in the seventh EULEP dosimetry intercomparison  

NASA Astrophysics Data System (ADS)

Several dosimetry intercomparisons for whole body irradiation of mice have been organized by the European Late Effects Project Group (EULEP). These studies were performed employing a mouse phantom loaded with LiF thermoluminescent dosemeters (TLDs). In-phantom, the energy response of the LiF TLDs differs from free-in-air, due to spectral differences caused by attenuation and scatter of x-rays. From previous studies, energy response correction factors in-phantom relative to free-in-air were available for full scatter conditions. In the more recent intercomparisons, however, full scatter conditions were not always employed by the participants. Therefore, Monte Carlo calculations of radiation transport were performed to verify the LiF TLD energy response correction factors in-phantom relative to free-in-air for full scatter conditions and to obtain energy response correction factors for geometries where full scatter conditions are not met. For incident x-rays with HVLs in the 1 to 3.5 mm Cu range, the energy response correction factor in-phantom deviates by 2 to 4 per cent from that measured free-in-air. This is in reasonable agreement with previously published results. The energy response correction factors obtained from the present study refer to a calibration in terms of muscle tissue dose in-phantom using gamma rays. For geometries where full scatter conditions are not fulfilled, the energy response correction factors are different by up to about 3 per cent at maximum from that at full scatter conditions. The dependence of the energy response correction factor as a function of the position in-phantom is small, i.e. about 1 per cent at maximum between central and top or bottom positions.

Zoetelief, J.; Jansen, J. Th M.

1997-08-01

181

Chiral corrections to the scalar form factor in B{sub q}{yields}D{sub q} transitions  

SciTech Connect

We consider chiral loop corrections to the scalar form factor in B{sub q}{yields}D{sub q}l{nu} decays. First we consider chiral corrections to the 1/m{sub Q} suppressed operators and then we propose a procedure for the extraction of the relevant form factor using lattice QCD results. In particular, the extraction of a B*{yields}D* matrix element on the lattice can be used to determine all the necessary 1/m{sub Q} suppressed contributions to the scalar form factor in B{yields}D transitions. In the case of (B{sub s}{yields}D{sub s})/(B{yields}D) decay rate ratios we speculate that effects of kinematics and chiral corrections tend to cancel for the scalar form factor contributions. In particular the 1/m{sub Q} suppression of chiral corrections is compensated by the potentially large SU(3) flavor symmetry breaking corrections. The calculated corrections are relevant for the precise determination of possible new physics effects in B{sub q}{yields}D{sub q}l{nu} decays.

Eeg, Jan O. [University of Oslo, Physics Department, P. O. Box 1048 Blindern, N-0316 Oslo 3 (Norway); Fajfer, Svjetlana [J. Stefan Institute, Jamova 39, P. O. Box 3000, 1001 Ljubljana (Slovenia); Department of Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Kamenik, Jernej F. [J. Stefan Institute, Jamova 39, P. O. Box 3000, 1001 Ljubljana (Slovenia); INFN, Laboratori Nazionali di Frascati, I-00044 Frascati (Italy)

2008-10-01

182

A Family of Electronic Ballasts Integrating Power Factor Correction and Power Control Stages to Supply HPS Lamps  

Microsoft Academic Search

This paper presents a family of high power factor electronic ballasts applied to the public lighting system. Flyback, buck-boost, boost or SEPIC converter is employed in the power factor correction stage, integrated to the power control stage through a single active switch. The use of a half-bridge inverter, to supply the lamp, becomes possible through the employment of a flyback

Tiago Bandeira Marchesan; Murilo Cervi; Alexandre Campos; R. N. do Prado

2006-01-01

183

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

Microsoft Academic Search

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

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

2012-01-01

184

Temperature regulation of virulence factors in the pathogen Vibrio coralliilyticus.  

PubMed

Sea surface temperatures (SST) are rising because of global climate change. As a result, pathogenic Vibrio species that infect humans and marine organisms during warmer summer months are of growing concern. Coral reefs, in particular, are already experiencing unprecedented degradation worldwide due in part to infectious disease outbreaks and bleaching episodes that are exacerbated by increasing SST. For example, Vibrio coralliilyticus, a globally distributed bacterium associated with multiple coral diseases, infects corals at temperatures above 27 °C. The mechanisms underlying this temperature-dependent pathogenicity, however, are unknown. In this study, we identify potential virulence mechanisms using whole genome sequencing of V. coralliilyticus ATCC (American Type Culture Collection) BAA-450. Furthermore, we demonstrate direct temperature regulation of numerous virulence factors using proteomic analysis and bioassays. Virulence factors involved in motility, host degradation, secretion, antimicrobial resistance and transcriptional regulation are upregulated at the higher virulent temperature of 27 °C, concurrent with phenotypic changes in motility, antibiotic resistance, hemolysis, cytotoxicity and bioluminescence. These results provide evidence that temperature regulates multiple virulence mechanisms in V. coralliilyticus, independent of abundance. The ecological and biological significance of this temperature-dependent virulence response is reinforced by climate change models that predict tropical SST to consistently exceed 27 °C during the spring, summer and fall seasons. We propose V. coralliilyticus as a model Gram-negative bacterium to study temperature-dependent pathogenicity in Vibrio-related diseases. PMID:22158392

Kimes, Nikole E; Grim, Christopher J; Johnson, Wesley R; Hasan, Nur A; Tall, Ben D; Kothary, Mahendra H; Kiss, Hajnalka; Munk, A Christine; Tapia, Roxanne; Green, Lance; Detter, Chris; Bruce, David C; Brettin, Thomas S; Colwell, Rita R; Morris, Pamela J

2011-12-08

185

Temperature regulation of virulence factors in the pathogen Vibrio coralliilyticus  

PubMed Central

Sea surface temperatures (SST) are rising because of global climate change. As a result, pathogenic Vibrio species that infect humans and marine organisms during warmer summer months are of growing concern. Coral reefs, in particular, are already experiencing unprecedented degradation worldwide due in part to infectious disease outbreaks and bleaching episodes that are exacerbated by increasing SST. For example, Vibrio coralliilyticus, a globally distributed bacterium associated with multiple coral diseases, infects corals at temperatures above 27?°C. The mechanisms underlying this temperature-dependent pathogenicity, however, are unknown. In this study, we identify potential virulence mechanisms using whole genome sequencing of V. coralliilyticus ATCC (American Type Culture Collection) BAA-450. Furthermore, we demonstrate direct temperature regulation of numerous virulence factors using proteomic analysis and bioassays. Virulence factors involved in motility, host degradation, secretion, antimicrobial resistance and transcriptional regulation are upregulated at the higher virulent temperature of 27?°C, concurrent with phenotypic changes in motility, antibiotic resistance, hemolysis, cytotoxicity and bioluminescence. These results provide evidence that temperature regulates multiple virulence mechanisms in V. coralliilyticus, independent of abundance. The ecological and biological significance of this temperature-dependent virulence response is reinforced by climate change models that predict tropical SST to consistently exceed 27?°C during the spring, summer and fall seasons. We propose V. coralliilyticus as a model Gram-negative bacterium to study temperature-dependent pathogenicity in Vibrio-related diseases.

Kimes, Nikole E; Grim, Christopher J; Johnson, Wesley R; Hasan, Nur A; Tall, Ben D; Kothary, Mahendra H; Kiss, Hajnalka; Munk, A Christine; Tapia, Roxanne; Green, Lance; Detter, Chris; Bruce, David C; Brettin, Thomas S; Colwell, Rita R; Morris, Pamela J

2012-01-01

186

Investigation of correction factors for non-reference conditions in ion chamber photon dosimetry with Monte-Carlo simulations  

Microsoft Academic Search

Current dosimetry protocols require geometrical reference conditions for the determination of absorbed dose in external radiotherapy. Whenever these geometrical conditions cannot be maintained the application of additional corrections becomes necessary, in principle. The current DIN6800-2 protocol includes a corresponding factor kNR, but numerical values are lacking and no definite information about the magnitude of this correction is available yet.This study

Jörg Wulff; Johannes T. Heverhagen; Heiko Karle; Klemens Zink

2010-01-01

187

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

188

Factors influencing stereoacuity levels after surgery to correct unilateral developmental cataracts in children  

PubMed Central

AIM To evaluate factors influencing stereoacuity after surgery to correct unilateral developmental pediatric cataracts. METHODS We retrospectively surveyed 110 patients who had undergone removal of unilateral acquired developmental cataracts and primary posterior chamber intraocular lens implantation between February 1992 and December 2009. In all patients, stereoacuity was assessed using the Titmus test at the last follow-up period of minimum 2 years after surgery. Patients were divided into two groups according to the extent of stereoacuity: group 1 (n=42) had stereoacuity values?100sec/arc and group 2 (n=68) values >100sec/arc. The values of ten parameters associated with stereoacuity were measured in each group: Cataract types, preoperative best corrected visual acuity (BCVA) of the affected eyes, preoperative inter-ocular difference of BCVA, age at cataract surgery, operative method, secondary cataract, postoperative strabismus, postoperative BCVA of the affected eyes, postoperative inter-ocular difference of BCVA, and anisometropia. RESULTS The extent of stereoacuity was significantly associated with both operative method and secondary cataract (P=0.000 and P=0.016, respectively). All patients in whom the posterior capsule was preserved, had poor stereoacuity >100sec/arc. Significant correlations with the extent of stereoacuity were found with postoperative strabismus (P=0.048), postoperative BCVA of the affected eyes (P=0.002), anisometropia (P=0.034). CONCLUSION : Postoperative stereoacuity was better in patients who underwent either optic capture or anterior vitrectomy after posterior continuous curvilinear capsulorhexis, and who didn't develop secondary cataracts or strabismus postoperatively. Furthermore, postoperative BCVA of the affected eyes, and anisometropia influenced the stereoacuity of the patients surgically treated for unilateral developmental pediatric cataracts.

Lee, Soo-Jung; Kim, Wan-Soo

2013-01-01

189

First lattice QCD study of the ? ? ? n axial and vector form factors with SU ( 3 ) breaking corrections  

Microsoft Academic Search

We present the first quenched lattice QCD study of the form factors relevant for the hyperon semileptonic decay ???n??. The momentum dependence of both axial and vector form factors is investigated and the values of all the form factors at zero-momentum transfer are presented. Following the same strategy already applied to the decay K0?????, the SU(3)-breaking corrections to the vector

D. Guadagnoli; V. Lubicz; M. Papinutto; S. Simula

2007-01-01

190

Prevalence and associated factors of depressive symptoms among Chinese male correctional officers.  

PubMed

OBJECTIVES: Chinese correctional officers (COs) consist of frontline COs in direct contact with the prisoners and non-frontline COs (including administrative staff and professionals). Male COs compose the majority of Chinese COs, especially for frontline COs. Although they are quite susceptible to depressive symptoms due to highly risky and stressful working environment, few studies focus on this issue. This study aimed to evaluate the prevalence of depressive symptoms and to explore its associated factors among Chinese male frontline and non-frontline COs. METHODS: This cross-sectional study was performed during the period of March/April 2011. The study population comprised of 1,900 male COs in four male prisons in a province of northeast China. A questionnaire including the Center for Epidemiological Studies Depression Scale, demographic factors, work conditions, effort-reward imbalance questionnaire was distributed to these COs. A total of 1,494 effective respondents became our subjects (981 frontline COs and 513 non-frontline COs). Frontline and non-frontline COs were analyzed separately. RESULTS: Approximately 61.4 % of Chinese male COs had depressive symptoms (63.5 % in frontline COs and 57.3 % in non-frontline COs). Multivariate logistic analyses showed that effort-reward ratio, overcommitment, chronic disease, and threat perception were associated with depressive symptoms in frontline and non-frontline COs, whereas weekly work time had an effect only in frontline COs. CONCLUSIONS: Chinese male COs, especially frontline COs, might have high-level prevalence of depressive symptoms. Moreover, this study had identified important risk factors that might be important in planning strategies for prevention and intervention of depressive symptoms for Chinese male COs. PMID:23609322

Sui, Guo-Yuan; Hu, Shu; Sun, Wei; Wang, Yang; Liu, Li; Yang, Xiao-Shi; Wang, Lie

2013-04-23

191

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

192

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

PubMed

The method for the calculation of correction factors is presented, which can be used for the assessment of the mean annual radon concentration on the basis of 1-month or 3-month indoor measurements. Annual radon concentration is an essential value for the determination of the annual dose due to radon inhalation. The measurements have been carried out in 132 houses in Poland over a period of one year. The passive method of track detectors with CR-39 foil was applied. Four thermal-precipitation regions in Poland were established and correction factors were calculated for each region, separately for houses with and without basements. PMID:21652217

Kozak, K; Mazur, J; Koz?owska, B; Karpi?ska, M; Przylibski, T A; Mamont-Cie?la, K; Grz?dziel, D; Stawarz, O; Wysocka, M; Dorda, J; Zebrowski, A; Olszewski, J; Hovhannisyan, H; Dohojda, M; Kapa?a, J; Chmielewska, I; K?os, B; Jankowski, J; Mnich, S; Ko?odziej, R

2011-05-24

193

Factors affecting characterization of bulk high-temperature superconductors  

Microsoft Academic Search

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

1997-01-01

194

Rigid protein motion as a model for crystallographic temperature factors  

SciTech Connect

The extent to which the librations of rigid molecules can model the crystallographic temperature factor profiles of proteins has been examined. For all proteins considered, including influenza virus hemagglutinin, glutathione reductase, myohemerythrin, myoglobin, and streptavidin, a simple 10-parameter model is found to reproduce qualitatively the patterns of maxima and minima in the isotropic backbone mean-square displacements. Large deviations between the rigid molecule and individual atomic temperature factors are found to be correlated with a region in hemagglutinin for which the refined structural model is unsatisfactory and with errors in the structure in a partially incorrect model of myohemerythrin. For the high-resolution glutathione reductase structure, better results are obtained on treating each of the compact domains in the structure as independent rigid bodies. The method allows for the refinement of reliable temperature factors with the introduction of minimal parameters and may prove useful for the evaluation of models in the early stages of x-ray structure refinement. While these results by themselves do not establish the nature of the underlying displacements, the success of the rigid protein model in reproducing qualitative features of temperature factor profiles suggests that rigid body refinement results should be considered in any interpretation of crystallographic thermal parameters.

Kuriyan, J. (Rockefeller Univ., New York, NY (United States)); Weis, W.I. (Columbia Univ., New York, NY (United States))

1991-04-01

195

Gene Conversion: Temperature Data from Sordaria fimicola on the Correction of Mis-paired Bases  

Microsoft Academic Search

CORRECTION of mis-paired bases in hybrid DNA is a basic postulate of current models of gene conversion and recombination1-5. Although some models invoke different origins of hybrid DNA, they involve similar repair processes. At each heterozygous site in a region of hybrid DNA, there are three possibilities: repair to wild type, repair to mutant and non-repair.

B. C. Lamb

1968-01-01

196

Correction of the AGA NX-19 MOD Data-Processing System for Real Gas Factors of Type H Natural Gas.  

National Technical Information Service (NTIS)

The BR-KORR.3H calculating system describes the real gas behaviour of type H natural gases at pressures up to 90 bar and temperatures between -10 exp 0 C and 30 exp 0 C. The calculation system is in fact a correction formula for the existing AGA NX-19 mod...

M. Jaeschke B. Harbrink

1982-01-01

197

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

PubMed

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

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

2013-05-01

198

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

199

Dynamic modeling of PWM and single-switch single-stage power factor correction converters  

NASA Astrophysics Data System (ADS)

The concept of averaging has been used extensively in the modeling of power electronic circuits to overcome their inherent time-variant nature. Among various methods, the PWM switch modeling approach is most widely accepted in the study of closed-loop stability and transient response because of its accuracy and simplicity. However, a non-ideal PWM switch model considering conduction losses is not available except for converters operating in continuous conduction mode (CCM) and under small ripple conditions. Modeling of conduction losses under large ripple conditions has not been reported in the open literature, especially when the converter operates in discontinuous conduction mode (DCM). In this dissertation, new models are developed to include conduction losses in the non-ideal PWM switch model under CCM and DCM conditions. The developed model is verified through two converter examples and the effect of conduction losses on the steady state and dynamic responses of the converter is also studied. Another major constraint of the PWM switch modeling approach is that it heavily relies on finding the three-terminal PWM switch. This requirement severely limits its application in modeling single-switch single-stage power factor correction (PFC) converters, where more complex topological structures and switching actions are often encountered. In this work, we developed a new modeling approach which extends the PWM switch concept by identifying the charging and discharging voltages applied to the inductors. The new method can be easily applied to derive large-signal models for a large group of PFC converters and the procedure is elaborated through a specific example. Finally, analytical results regarding harmonic contents and power factors of various PWM converters in PFC applications are also presented here.

Zhu, Guangyong

200

Investigation of systematic uncertainties in Monte Carlo-calculated beam quality correction factors.  

PubMed

Modern Monte Carlo codes allow for the calculation of ion chamber specific beam quality correction factors k(Q), which are needed for dosimetry in radiotherapy. While statistical (type A) uncertainties of the calculated data can be minimized sufficiently, the influence of systematic (type B) uncertainties is mostly unknown. This study presents an investigation of systematic uncertainties of Monte Carlo-based k(Q) values for a NE2571 thimble ion chamber, calculated with the EGSnrc system. Starting with some general investigation on transport parameter settings, the influence of geometry and source variations is studied. Furthermore, a systematic examination of uncertainties due to cross section is introduced by determining the sensitivity of k(Q) results to changes in cross section data. For this purpose, single components of the photon cross sections and the mean excitation energy I in the electron stopping powers are varied. The corresponding sensitivities are subsequently applied with information of standard uncertainties for the cross section data found in the literature. It turns out that the calculation of k(Q) factors with EGSnrc is mostly insensitive to transport settings within the statistical uncertainties of approximately 0.1%. Severe changes in the dimensions of the chamber lead to comparatively small, insignificant changes. Further, the inclusion of realistic beam models, delivering a complete phase space instead of simple photon spectra, does not significantly influence the result. However, the uncertainties in electron cross sections have an impact on the final uncertainty of k(Q) to a comparatively large degree. For the NE2571 chamber investigated in this work, this uncertainty amounts to 0.4% at 24 MV, decreasing to 0.2% at 6 MV. PMID:20668340

Wulff, J; Heverhagen, J T; Zink, K; Kawrakow, I

2010-07-29

201

Risk factors for adjacent segment degeneration after surgical correction of degenerative lumbar scoliosis  

PubMed Central

Background: Degenerative lumbar scoliosis surgery can lead to development of adjacent segment degeneration (ASD) after lumbar or thoracolumbar fusion. Its incidence, risk factors, morbidity and correlation between radiological and clinical symptoms of ASD have no consensus. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and certain imperative parameters. Materials and Methods: 98 patients who had undergone surgical correction and lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative lumbar scoliosis with a minimum 5 year followup were included in the study. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and imperative patient parameters like age at operation, sex, body mass index (BMI), medical comorbidities and bone mineral density (BMD). The radiological parameters taken into consideration were Cobb's angle, angle type, lumbar lordosis, pelvic incidence, intercristal line, preoperative existence of an ASD on plain radiograph and magnetic resonance imaging (MRI) and surgical parameters were number of the fusion level, decompression level, floating OP (interlumbar fusion excluding L5-S1 level) and posterolateral lumbar interbody fusion (PLIF). Clinical outcomes were assessed with the Visual Analogue Score (VAS) and Oswestry Disability Index (ODI). Results: ASD was present in 44 (44.9%) patients at an average period of 48.0 months (range 6-98 months). Factors related to occurrence of ASD were preoperative existence of disc degeneration (as revealed by MRI) and age at operation (P = 0.0001, 0.0364). There were no statistically significant differences between radiological adjacent segment degeneration and clinical results (VAS, P = 0.446; ODI, P = 0.531). Conclusions: Patients over the age of 65 years and with preoperative disc degeneration (as revealed by plain radiograph and MRI) were at a higher risk of developing ASD.

Ha, Kee-yong; Son, Jong-Min; Im, Jin-Hyung; Oh, In-Soo

2013-01-01

202

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

2013-01-25

203

Absolute spectrophotometry of galactic Wolf-Rayet stars - Effective temperatures and bolometric corrections  

Microsoft Academic Search

The recent data of absolute measurements of flux emitted in the visible continua of some galactic Wolf-Rayet stars are presented. Correction of interstellar reddening is made in detail, prior to the determinations of color excesses, E(B-V). The dereddened fluxes combined with IUE and ANS ultraviolet measurements are then compared to those of LTE plane-parallel model atmospheres of Kurucz (1979) and

Jong Ok Woo

1988-01-01

204

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.

Gelman, David; Schwartz, Steven D.

2011-01-01

205

Disorders of phospholipids metabolism in the brain of white rats during experimental liver cirrhosis and corrective effect of antioxidant factors  

Microsoft Academic Search

1 The goal of the present work was to study the peculiarities of the phospholipids?phospholipid (PL-PL) ratio in white rat brain in CCl 4 -induced liver cirrhosis (LC) and the corrective effect of antioxidant factors such as ? -tocopherol ( ? -TPh) and sodium thiosulfate (STS). The experiments were performed with outbred white male rats weighing 180?200 g. Experimental LC

A. S. Margaryan; L. A. Simonyan; R. B. Badalyan; I. G. Batikyan; A. A. Simonyan

2008-01-01

206

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

Microsoft Academic Search

The method for the calculation of correction factors is presented, which can be used for the assessment of the mean annual radon concentration on the basis of 1-month or 3-month indoor measurements. Annual radon concentration is an essential value for the determination of the annual dose due to radon inhalation. The measurements have been carried out in 132 houses in

K. Kozak; J. Mazur; B. Koz?owska; M. Karpi?ska; T. A. Przylibski; K. Mamont-Cie?la; D. Grz?dziel; O. Stawarz; M. Wysocka; J. Dorda; A. ?ebrowski; J. Olszewski; H. Hovhannisyan; M. Dohojda; J. Kapa?a; I. Chmielewska; B. K?os; J. Jankowski; S. Mnich; R. Ko?odziej

207

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

NASA Astrophysics Data System (ADS)

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.; Wimmer, C.; Fantz, U.

2012-05-01

208

Solar irradiance-corrected spatial interpolation of hourly temperature in complex terrain  

Microsoft Academic Search

Converting temperature forecasts and observations at irregular points into a gridded data set is widely used for regional scale ecosystem modeling and model-based decision making. Neglect of terrain effects in spatial interpolation schemes for short-term temperature assessment may cause erroneous results in mountainous regions, where the observation network ineffectively covers complex terrain. We suggest a spatial interpolation model for daytime

Uran Chung; Jin I. Yun

2004-01-01

209

Correcting the Cenozoic ? 18O deep-sea temperature record for Antarctic ice volume  

Microsoft Academic Search

The oxygen isotope signal in benthic foraminifera from deep-sea cores is mainly determined by deep-ocean temperature and land ice volume. Separating the temperature and ice volume signals is a key step in understanding the evolution of Cenozoic climate. Except for the last few million years, fluctuations in land ice volume were determined mainly by the size of the Antarctic ice

Johannes Oerlemans

2004-01-01

210

Monte-Carlo-based perturbation and beam quality correction factors for thimble ionization chambers in high-energy photon beams  

Microsoft Academic Search

This paper presents a detailed investigation into the calculation of perturbation and beam quality correction factors for ionization chambers in high-energy photon beams with the use of Monte Carlo simulations. For a model of the NE2571 Farmer-type chamber, all separate perturbation factors as found in the current dosimetry protocols were calculated in a fixed order and compared to the currently

J. Wulff; J. T. Heverhagen; K. Zink

2008-01-01

211

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

212

Development & Implementation of the Best Means of Correcting Vaisala Radiosonde Humidity & Temperature Measuremwnts  

SciTech Connect

The first of two main goals of this project has been to develop and implement a correction procedure that maximizes the accuracy of relative humidity (RH) measurements from ARM (Vaisala) radiosondes, and to evaluate the correction algorithm using a dataset of simultaneous measurements from Vaisala radiosones and the reference-quality NOAA/CMDL cryogenic hygrometer. The second main goal has been to determine how comparison of radiosonde RH measurements to reference-quality RH measurements obtained routinely in the ventilated ''mailbox'' at the SGP launch site can be used to characterize and improve the accuracy of ARM radiosonde measurements. This project is important to a broad variety of ARM research areas, including initializing numerical models and evaluating model results, improving the accuracy of radiative transfer calculations and parameterizations, evaluating water vapor retrievals from ground-based or satellite instruments, and developing water vapor and cloud parameterizations. Tobin et al. (2003) showed that in order to achieve a target accuracy of 1 W/m2 in the downwelling and outgoing longwave flux, the water vapor profile must be known with an absolute accuracy of 2% in the total-column integrated water vapor, and 10% in the upper troposphere (UT).

Larry Miloshevich

2004-07-26

213

Comparisons of experimental and computed protein anisotropic temperature factors.  

PubMed

Because of its appealing simplicity, the anisotropic network model (ANM) has been widely accepted and applied to study many molecular motion problems: such as ribosome motions, the molecular mechanisms of GroEL-GroES function, allosteric changes in hemoglobin, motor-protein motions, and conformational changes in general. However, the validity of the ANM has not been closely examined. In this work, we use ANM to predict the anisotropic temperature factors of proteins obtained from X-ray and NMR data. The rich, directional anisotropic temperature factor data available for hundreds of proteins in the protein data bank are used as validation data to closely test the ANM model. The significance of this work is that it presents a timely, important evaluation of the model, shows the extent of its accuracy in reproducing experimental anisotropic temperature factors, and suggests ways to improve the model. An improved model will help us better understand the internal dynamics of proteins, which in turn can greatly expand the usefulness of the models, which has already been demonstrated in many applications. PMID:19127591

Yang, Lei; Song, Guang; Jernigan, Robert L

2009-07-01

214

COD services in community correctional settings: an examination of organizational factors that affect service delivery.  

PubMed

Little is known about service delivery for those in the correctional system with co-occurring mental health and substance abuse disorders (COD). Using data from the National Criminal Justice Treatment Practices survey (NCJTP) on community corrections and jail agencies, this study found that correctional organizations that offer COD services differ from agencies that do not. Organizations that respond to the needs of COD offenders tend to be more "service friendly," rank higher on measures of various dimensions of organizational climate that embrace learning and goal achievement, and tend to adopt more innovations, particularly those classified as evidence-based practices. These survey findings indicate that correctional agencies who serve COD offenders are in a better position to be responsive to the changing service needs of the populations, and are more likely to be able to balance public safety and treatment goals. Future steps to develop support environments for COD assessment and treatment services are discussed in light of these findings. PMID:18683196

Taxman, Faye S; Cropsey, Karen L; Melnick, Gerald; Perdoni, Matthew L

2008-01-01

215

Transformations from Theoretical Hertzsprung-Russell Diagrams to Color-Magnitude Diagrams: Effective Temperatures, B-V Colors, and Bolometric Corrections  

NASA Astrophysics Data System (ADS)

This paper provides improved numerical relations between effective temperatures of stars, their B - V colors, and their bolometric corrections (B Cs) for the purpose of comparing theoretical stellar evolutionary calculations to color-magnitude diagrams of star clusters. Temperatures and bolometric correction measurements for 335 stars from the literature form the observational basis for the transformations. Measured temperatures range from 2900 to 52,500 K. Polynomial fits to the observations give relations between effective temperatures and B - V colors and between temperatures and bolometric corrections. Hot supergiants appear to have a Teff:B-V relation slightly different from those of main-sequence stars, subgiants, and giants. All luminosity classes appear to follow a unique Teff:BC relation. The Teff:BC relation for stars with temperatures less than ˜5000 K, however, is uncertain because temperatures of the coolest stars are determined from uncertain angular diameters.

Flower, Phillip J.

1996-09-01

216

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

Code of Federal Regulations, 2011 CFR

...SAFETY STANDARDS Pipe Design § 192.115 Temperature derating factor (T ) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105...determined as follows: Gas temperature in degrees...

2011-10-01

217

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

Code of Federal Regulations, 2012 CFR

...SAFETY STANDARDS Pipe Design § 192.115 Temperature derating factor (T ) for steel pipe. The temperature derating factor to be used in the design formula in § 192.105...determined as follows: Gas temperature in...

2012-10-01

218

On the need for bias correction of regional climate change projections of temperature and precipitation  

NASA Astrophysics Data System (ADS)

Within the framework of the European project ENSEMBLES (ensembles-based predictions of climate changes and their impacts) we explore the systematic bias in simulated monthly mean temperature and precipitation for an ensemble of thirteen regional climate models (RCMs). The models have been forced with the European Centre for Medium Range Weather Forecasting Reanalysis (ERA40) and are compared to a new high resolution gridded observational data set. We find that each model has a distinct systematic bias relating both temperature and precipitation bias to the observed mean. By excluding the twenty-five percent warmest and wettest months, respectively, we find that a derived second-order fit from the remaining months can be used to estimate the values of the excluded months. We demonstrate that the common assumption of bias cancellation (invariance) in climate change projections can have significant limitations when temperatures in the warmest months exceed 4-6 °C above present day conditions.

Christensen, Jens H.; Boberg, Fredrik; Christensen, Ole B.; Lucas-Picher, Philippe

2008-10-01

219

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

SciTech Connect

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

Farbshtein, I. I., E-mail: Iosif.Farbshtein@mail.ioffe.ru; Chernyaev, A. V.; Shamshur, D. V.; Averkiev, N. S., E-mail: averkiev@les.ioffe.r [Ioffe Physicotechnical Institute (Russian Federation)

2010-08-15

220

Temperature calibration and correction report for PMEL trace gas cruises 1986-1989. Technical memo  

SciTech Connect

Present methods for evaluating the in situ concentrations of gases in surface seawater require accurate temperature measurements. Temperature data from each of 5 PMEL cruises over the years 1986 to 1989 are discussed independently to describe the different types of data available and the methods of analysis. The seawater warming between the inlet and the equilibrator is shown for each cruise as calculated by a point-by-point method and a regression method, and both methods are discussed. The data are given in an accompanying diskette in ASCII format.

Murphy, P.P.; Cosca, C.; Lee, D.C.; Feely, R.A.

1993-02-01

221

Reference dosimetry condition and beam quality correction factor for CyberKnife beam  

SciTech Connect

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 k{sub Q} for an ordinary 6 MV linear accelerator has been temporally substituted for the k{sub Q} of the CyberKnife in many sites. Therefore, the reference conditions and k{sub Q} 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 k{sub Q} 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 k{sub Q} for ionization chambers of a suitable size were determined and tabulated as a function of measurable beam quality indexes in the CyberKnife beam.

Kawachi, Toru; Saitoh, Hidetoshi; Inoue, Mitsuhiro; Katayose, Tetsurou; Myojoyama, Atsushi; Hatano, Kazuo [Tokyo Metropolitan University Graduate School of Human Health Sciences, Tokyo, Japan and Chiba Cancer Center, Chiba (Japan); Tokyo Metropolitan University Graduate School of Human Health Sciences, Tokyo (Japan); Yokahama CyberKnife Center, Yokohama (Japan); Tokyo Metropolitan University Graduate School of Human Health Sciences, Tokyo (Japan); Chiba Cancer Center, Chiba (Japan)

2008-10-15

222

Analysis of biologically-derived small particles--searching for geometry correction factors using Monte Carlo simulation.  

PubMed

A Monte Carlo simulation was used to determine geometry correction factors that increase accuracy of quantitative X-ray microanalysis of laterally semithick biological materials. A model composed of cellulose with homogeneously distributed biological elements and lateral dimensions between 0.5-25 ?m was chosen. The specimen was exposed to 5, 10, and 15 keV electrons, the net intensities of characteristic X-rays registered for the elements, and presented as a function of the lateral dimensions of the model. This showed the double decay exponential function fitted the distribution of X-ray intensities in relation to the model size. The applicability of the function as a correction method was successfully tested for 30 specimens with varying composition and dimensions. The value of relative error decreased from ±60% to ±5% when the correction was applied. Moreover, the minimal lateral size of the material was defined, below which the correction is not required. The simulation also revealed that the difference of the weighted sum of Z²/A between the unknown and the standard could reach 25% without significant influence on the quantitative results. The correction method could be helpful for accurate assessment of elemental composition in biological or organic matrices, when their lateral dimensions are smaller than the distribution range. PMID:23302468

Tylko, Grzegorz

2013-01-10

223

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

NASA Astrophysics Data System (ADS)

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

Cao, Yanpeng; Tisse, Christel-Loic

2013-06-01

224

An investigation of factors affecting detector and geometric correction in normalization of 3-D PET data  

SciTech Connect

Normalization in three-dimensional (3-D) positron emission tomography (PET) comprises two aspects: correction for differential detector response and correction for geometric effects. Comparison of rotating rod source and uniform cylinder data suggests that the position of the source used to correct for sensitivity should be similar to that of the emission data. A plane source method has been devised that used a moving line source that traverses the transaxial field-of-view, emulating a plane source, but without the problems associated with using a conventional plane source in 3-D (uniformity, scatter, cost, etc.). This device has been used to record high count density acquisitions for direction normalization of emission data and also to examine geometric effects with increasing azimuthal ({phi}) and polar ({theta}) angles in the 3-D data set. The data have confirmed observations of two distinct geometric patterns seen previously in two-dimensional PET: an overall transaxial sensitivity profile that decreases toward the center of the projection and a crystal interference profile that changes with position in the block. Correction for the first geometric component removes a low-sensitivity ``hole`` in 3-D PET reconstructions, and correction for the second component removes ``ring`` artifacts. The direct normalization approach produces an artifact along the central axis of the scanner. A quantitative index of nonuniformity for 1-pixel-thick annular regions of interest showed a reduction from 60% nonuniformity with no corrections to less than 15% when the plane source data were used to directly normalize the emission data. The moving line source provides high quality data and may be an appropriate normalization device for 3-D PET.

Bailey, D.L.; Grootoonk, S.; Jones, T. [Hammersmith Hospital, London (United Kingdom). MRC Cyclotron Unit; Townsend, D.W.; Kinahan, P.E. [Univ. of Pittsburgh Medical Center, PA (United States). PET Facility

1996-12-01

225

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

SciTech Connect

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

Wang, L. L. W.; Rogers, D. W. O. [Ottawa Carleton Institute of Physics, Carleton University Campus, Ottawa, Ontario K1S 5B6 (Canada)

2008-10-15

226

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

227

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

2012-04-13

228

Single-switch flyback power-factor-corrected AC\\/DC converter with loosely regulated intermediate storage capacitor voltage  

Microsoft Academic Search

Single-stage power-factor-corrected AC\\/DC converters (SSPFC) usually bear high voltage stress on the intermediate storage capacitor due to the lack of control of this voltage. The storage capacitor voltage varies largely with line voltage and load current and is usually higher than the peak line voltage. This paper presents a new single-switch SSPFC based on flyback topology for which the storage

Dylan Dah-chuan Lu; David Ki-wai Cheng; Yim-shu Lee

2003-01-01

229

Applying time-multiplexing control to single-stage forward-based power-factor-corrected converter  

Microsoft Academic Search

A new forward-based single-stage power-factor-corrected converter is proposed. A portion of input power is directly transferred to the output through the forward converter to improve the efficiency of power conversion. The flyback auxiliary circuit is added to the forward converter to reduce low line-frequency output voltage ripple. In an effort to lower the size and cost of the converter, a

Ting Sun; Dylan Dah-Chuan Lu

2009-01-01

230

A resonance power supply that provides dynamic power factor correction in capacitor input off-line converters  

Microsoft Academic Search

A dynamic power factor corrected resonance power supply employing a single high-speed gate-turn-off (GTO) thyristor is presented. Included is a description of the modes of operation and the design and evaluation of a 300 W, 80 kHz prototype model. Computer simulation of the prototype circuit is also discussed. An assessment of the possibility of using the converter for low-voltage applications

K. A. Amarasinghe; C. D. Manning

1990-01-01

231

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

232

Near room temperature power factor of metal sulfides films  

NASA Astrophysics Data System (ADS)

Metal chalcogenides are compounds with attractive transport properties to be used in thermoelectric applications. This manuscript shows the influence of temperature on power factor (?) of several metal sulphide films: CoS2, FeS2, NiS2 and PdS. Films were prepared by direct sulphuration of the metals at 700K. Sulfide films were characterized by perfilometry, XRD and SEM-EDX. Transport properties (Seebeck coefficient and resitivity) were measured from 300K to 700 K under vacuum. Whereas CoS2 shows a semi-metallic behaviour, FeS2 and PdS exhibit a clearly semiconductor character. Moreover, despite CoS2 is the sulfide with highest power factor, FeS2 seems to be the most adequate to be implement considering key criteria such as cost and availability of raw elements.

Clamagirand, J. M.; Ares, J. R.; Ferrer, I. J.; Sánchez, C.

2012-06-01

233

Factors Affecting the Ability of Energy Functions to Discriminate Correct from Incorrect Folds  

Microsoft Academic Search

Eighteen low and medium resolution empirical energy functions were tested for their ability to distinguish correct from incorrect folds from three test sets of decoy protein conformations. The energy functions included 13 pairwise potentials of mean force, covering a wide range of functional forms and methods of parameterization, four potentials that attempt to detect properly formed hydrophobic cores, and one

Britt H. Park; Enoch S. Huang; Michael Levitt

1997-01-01

234

Determination of correction factors for borehole natural gamma-ray measurements by Monte Carlo simulations  

NASA Astrophysics Data System (ADS)

The analysis of natural ?-ray spectra measured in boreholes has to take into account borehole parameters such as the presence of casings and borehole diameter. For large, high-efficiency ?-ray detectors, such as BGO-based systems, which employ full-spectrum data analysis, corresponding corrections were not previously determined. In a joint project of the Nuclear Geophysics Division of the Kernfysisch Versneller Instituut (NGD/KVI), Groningen, Medusa Explorations B.V. and the Dutch Institute for Applied Geosciences (TNO-NITG) a catalogue of corrections was constructed. Using the Monte Carlo code MCNP, the influence of steel casings, borehole diameter, central axis probe position and the diameter of the ?-ray detector on the ?-ray spectra has been investigated for nearly 20 geometries. The calculated ?-ray spectra are compared qualitatively and quantitatively. In a case study, ?-ray spectra from a borehole measured in a cased and uncased configuration are analyzed with simulated spectra. When no corrections are used, the activity concentrations deviated by as much as 50% between the two measurements. Taking into account the specific measurement geometry, the activity concentrations were found to be identical within the statistical and systematic uncertainties of the experiment for the same borehole, with and without casing. These results illustrate the need for borehole-specific corrections and this study demonstrates that Monte Carlo methods are a fast and reliable way to calibrate well-logging tools for a wide variety of configurations.

Mau?ec, M.; Hendriks, P. H. G. M.; Limburg, J.; de Meijer, R. J.

2009-10-01

235

Critical Factors in Mental Health Programming for Juveniles in Corrections Facilities  

ERIC Educational Resources Information Center

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

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

2006-01-01

236

Estimating the age of immature Chrysomya albiceps (Diptera: Calliphoridae), correcting for temperature and geographical latitude.  

PubMed

Developmental curves for Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) were established at 13 different constant temperatures using developmental landmarks and length as measures of age. The thermal summation constants (K) and developmental zeros (D (0)) were calculated for five developmental landmarks using the method described by Ikemoto and Takai (Environ Entomol 29:671-682, 2000). Comparison with the K and D (0) values of our findings to those of three previously published studies of C. albiceps suggests that K is directly proportional to geographic latitude, and D (0) is inversely proportional to both K and geographic latitude. Body size and developmental landmarks have a complex relationship because of trade-offs between mortality risk and female fecundity (as measured by body size) at non-optimal temperatures. This relationship can be summarized using superimposed isomorphen and isomegalen diagrams, which can then be used to make forensic estimates of postmortem intervals from larval body lengths. Finally, we recommend that future studies providing data for precise forensic estimates of postmortem intervals should use a relative temporal precision of about 10% of the total duration being measured. For many blowflies, this translates into a sampling interval of approximately every 2 h before hatching, 3 h before first ecdysis and 6 h before second ecdysis. PMID:17899152

Richards, Cameron S; Paterson, Iain D; Villet, Martin H

2007-09-26

237

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

NASA Astrophysics Data System (ADS)

The extensive use of non-linear and electronically switched loads in power system has lead to higher incidences of harmonic distortion of the voltage and current waveforms. Harmonic currents degrade power quality and are considered the main source of many system malfunctions. Technical guidelines and standards regarding suppressions of system harmonic contents have been enacted. This dissertation proposes several new three-phase power factor correction (PFC) schemes using single-phase PFC modules. An integrated single-switch approach is first proposed. This is essentially an add-on solution to standard ASD's. This approach is based on circulating third harmonic current between neutral and DC mid-point by utilizing a lossless resistor. Single-phase PFC emulates this resistor to control the amplitude of the current, which is implemented by the dynamic breaking chopper available in standard adjustable speed drives (ASD's). This approach is also capable of reducing harmonic distortion in multiple drives. Analysis, design and simulations are conducted to determine the performance of the proposed scheme with different line impedances and with and without dc-link inductance in the ASD. Experimental results are presented using commercial ASD retrofitted with the proposed approach. Second scheme proposes a three-phase PFC using two standard single-phase PFC modules. In this approach, three-phase input is transformed into two-phase by means of 0.14 pu autotransformer. Two standard single-phase PFC modules are employed to process two-phase power to do output. Split inductors and diodes are employed to limit the interaction between the two phases. A method to eliminate the interaction between phases is also described. Due to cascade operation of two PFC stages, low frequency (120Hz) ripple in dc-link is cancelled. An active interphase transformer (IPT) scheme is proposed to draw sinusoidal input line currents, in the third study. This scheme utilizes a unique combination of a low kVA 12-puse rectifier system with single-phase boost PFC. In response to load conditions, the amplitude of the triangular current from the secondary winding of the IPT is controlled by the boost PFC. The 0.05 pu PFC is not exposed to line transients under varying load conditions. The proposed system is rugged, and in the event of active control were to fail the system reverts to 12-pulse system with 5th and 7th harmonic cancellation. In the fourth study, a wide input range active multi-pulse rectifier for utility interface is proposed. The scheme combines multipulse method using Y-Delta transformer and boost rectifier modules. Diode switching vector is utilized to shape the input line currents. A current control scheme is proposed to achieve sinusoidal line current under wide range of input voltage changes and output load conditions. Analysis, design examples and Experimental results are detailed for each scheme.

Hahn, Jae-Hong

238

On the use of the correction factor with Japanese ozonesonde data  

NASA Astrophysics Data System (ADS)

In submitting data to the World Meteorological Organization (WMO) World Ozone and Ultraviolet Data Center (WOUDC), numerous ozonesonde stations include a correction factor (CF) that multiplies ozone concentration profile data so that the columns computed agree with column measurements from co-located ground-based and/or overpassing satellite instruments. We evaluate this practice through an examination of data from four Japanese ozonesonde stations: Kagoshima, Naha, Sapporo, and Tsukuba. While agreement between the sonde columns and Total Ozone Mapping Spectrometer (TOMS) or Ozone Mapping Instrument (OMI) is improved by use of the CF, agreement between the sonde ozone concentrations reported near the surface and data from surface monitors near the launch sites is negatively impacted. In addition, we find the agreement between the mean sonde columns without the CF and the ground-based Dobson instrument columns is improved by ~1.5 % by using the McPeters et al. (1997) balloon burst climatology rather than the constant mixing ratio assumption (that has been used for the data in the WOUDC archive) for the above burst height column estimate. Limited comparisons of coincident ozonesonde profiles from Hokkaido University with those in the WOUDC database suggest that while the application of the CFs in the stratosphere improves agreement, it negatively impacts the agreement in the troposphere. Finally and importantly, unexplained trends and changing trends in the CFs appear over the last 20 years. The overall trend in the reported CFs for the four Japanese ozonesonde stations from 1990-2010 is (-0.264 ± 0.036) × 10-2 yr-1; but from 1993-1999 the trend is (-2.18 ± 0.14) × 10-2 yr-1 and from 1999-2009 is (1.089 ± 0.075) × 10-2 yr-1, resulting in a statistically significant difference in CF trends between these two periods of (3.26 ± 0.16) × 10-2 yr-1. Repeating the analysis using CFs derived from columns computed using the balloon-burst climatology, the trends are somewhat reduced, but remain statistically significant. Given our analysis, we recommend the following: (1) use of the balloon burst climatology is preferred to a constant mixing ratio assumption for determining total column ozone with sonde data; (2) if CFs are applied, their application should probably be restricted to altitudes above the tropopause; (3) only sondes that reach at least 32 km (10.5 hPa) before bursting should be used in data validation and/or ozone trend studies if the constant mixing ratio assumption is used to calculate the above burst column (as is the case for much of the data in the WOUDC archive). Using the balloon burst climatology, sondes that burst above 29 km (~16 hPa), and perhaps lower, can be used; and (4) all ozone trend studies employing Japanese sonde data should be revisited after a careful examination of the impact of the CF on the calculated ozone trends.

Morris, G. A.; Labow, G.; Akimoto, H.; Takigawa, M.; Fujiwara, M.; Hasebe, F.; Hirokawa, J.; Koide, T.

2013-02-01

239

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

240

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

241

Determination of correction factors for borehole natural gamma-ray measurements by Monte Carlo simulations  

Microsoft Academic Search

The analysis of natural gamma-ray spectra measured in boreholes has to take into account borehole parameters such as the presence of casings and borehole diameter. For large, high-efficiency gamma-ray detectors, such as BGO-based systems, which employ full-spectrum data analysis, corresponding corrections were not previously determined. In a joint project of the Nuclear Geophysics Division of the Kernfysisch Versneller Instituut (NGD\\/KVI),

M. Maucec; P. H. G. M. Hendriks; J. Limburg; R. J. de Meijer

2009-01-01

242

Determination of correction factors for borehole natural gamma-ray measurements by Monte Carlo simulations  

Microsoft Academic Search

The analysis of natural ?-ray spectra measured in boreholes has to take into account borehole parameters such as the presence of casings and borehole diameter. For large, high-efficiency ?-ray detectors, such as BGO-based systems, which employ full-spectrum data analysis, corresponding corrections were not previously determined. In a joint project of the Nuclear Geophysics Division of the Kernfysisch Versneller Instituut (NGD\\/KVI),

M. Mau?ec; P. H. G. M. Hendriks; J. Limburg; R. J. de Meijer

2009-01-01

243

Feynman Hibbs correction in classical molecular dynamics simulations of solid C60 under a progressively raised pressure and temperature  

NASA Astrophysics Data System (ADS)

Feynman-Hibbs corrections in molecular dynamics computer calculations of solid C60 are implemented within the classical effective pair potential approach. The potential model chosen for the site-site interactions is of the Buckingham exp-6 type (Rigby 1986 The Forces Between Molecules (New York: Oxford University Press)), fitted to the Cheng and Klein or the Kitaïgorodsky potential. Structural and thermodynamic properties of the C60 crystal lattice are investigated over a wide range of pressures and temperatures, and data obtained are compared to experimental results and those obtained from a classical approach (Baameur et al 2000 Phys. Status Solidi 220 821). It will be demonstrated that 'quantum corrections' applied in a simple quasi-classical simulations have a great influence upon most calculated properties and increase their accuracy when compared to classical approaches. The observed transition pressure with the distorted lattice and cell contraction compares favourably well with experimental data and equation of state calculations. All measured properties are reported together with the phonon density of states at different pressures.

Hammou, Z.; Lebsir, F.; Krallafa, A.; Hadjadj, A.; Bormann, D.

2005-03-01

244

A complete calculation of the order ?s2 correction to the Drell-Yan K-factor  

NASA Astrophysics Data System (ADS)

In this paper we present the complete calculation of the order ?s2 correction in the MS scheme to the Drell-Yan K-factor. All channels represented by the qq¯, qg, gg and qq subprocesses have been included now. One of our conclusions is that the O(?s2) part of the K-factor is dominated by the qq¯ as well as the qg reaction. The latter leads to a negative contribution over the whole energy range under investigation (0.5 TeV < sqrt(S) < 50 TeV). It even overwhelms the positive qq¯ contribution at large collider energies characteristic for LHC and SSC. It turns out that the order ?s2 corrected K-factor is quite insensitive to variations of the factorization scale M over the region 10 GeV < M < 1000 GeV. We also compare our results with the data obtained by UA1, UA2 and CDF. Supported by LAA, CERN, Geneva.

Hamberg, R.; van Neerven, W. L.; Matsuura, T.

1991-08-01

245

Nonaxisymmetric correction factors for the bounce-averaged electron Fokker-Planck equation  

NASA Astrophysics Data System (ADS)

The bounce-averaging procedure for the electron Fokker-Planck equation is extended to the case of nonaxisymmetric geometry, in order to calculate consistently electron ripple-induced losses in tokamak during rf heating and current drive experiments. New explicit expressions for the bounce-averaged coefficients are developed for circulating electrons but also for banana electrons. While the effect of magnetic ripple is fairly negligible for circulating electrons, nonaxisymmetric corrections become significantly larger for banana electrons as compared to the axisymmetric case.

Ju, M.; Basiuk, V.; Peysson, Y.

2002-02-01

246

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

247

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

PubMed

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

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

2002-08-01

248

Calculable corrections to brane black hole decay. II. Greybody factors for spin 1/2 and 1  

NASA Astrophysics Data System (ADS)

The production of black holes in extra-dimensional brane-world theories can lead to detectable signals via the Hawking evaporation of the black hole to brane-localized standard model modes. We calculate, as a function of partial wave number and number of toroidally compactified extra dimensions, the leading correction to the energy spectrum of such Hawking radiation (the greybody factors) for decay into spin-1/2 fermions and spin-1 gauge fields localized on the standard model brane. We derive the associated improved differential emission rates for both types of fields. We provide both simple expressions for the leading behavior of the greybody factors in the low-energy limit ?rH?1 and numerical evaluation of our full analytic expressions for the emission rates, valid for ?rH˜1. The full analytic expressions demonstrate that both the greybody factors and emission rates are enhanced as the number of extra dimensions increases.

Kanti, Panagiota; March-Russell, John

2003-05-01

249

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

PubMed

Sap flow measurements conducted with thermal dissipation probes (TDPs) are vulnerable to natural temperature gradient (NTG) bias. Few studies, however, attempted to explain the dynamics underlying the NTG formation and its influence on the sensors' signal. This study focused on understanding how the TDP signals are affected by negative and positive temperature influences from NTG and tested the novel cyclic heat dissipation (CHD) method to filter out the NTG bias. A series of three experiments were performed in which gravity-driven water flow was enforced on freshly cut stem segments of Fagus sylvatica L., while an artificial temperature gradient (ATG) was induced. The first experiment sought to confirm the incidence of the ATG on sensors. The second experiment established the mis-estimations caused by the biasing effect of the ATG on standard TDP measurements. The third experiment tested the accuracy of the CHD method to account for the ATG biasing effect, as compared with other cyclic correction methods. During experiments, sap flow measured by TDP was assessed against gravimetric measurements. The results show that negative and positive ATGs were comparable in pattern but substantially larger than field NTGs. Second, the ATG bias caused an overestimation of the standard TDP sap flux density of ?17 cm(3) cm(-2) h(-1) by 76%, and the sap flux density of ?2 cm(3) cm(-2) h(-1) by over 800%. Finally, the proposed CHD method successfully reduced the max. ATG bias to 25% at ?11 cm(3) cm(-2) h(-1) and to 40% at ?1 cm(3) cm(-2) h(-1). We concluded that: (i) the TDP method is susceptible to NTG especially at low flows; (ii) the CHD method successfully corrected the TDP signal and resulted in generally more accurate sap flux density estimates (mean absolute percentage error ranging between 11 and 21%) than standard constant power TDP method and other cyclic power methods; and (iii) the ATG enforcing system is a suitable way of re-creating NTG for future tests. PMID:22659459

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

2012-06-01

250

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

251

Geometrical factor correction in grazing incident x-ray fluorescence experiment.  

PubMed

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. PMID:22667609

Li, Wenbin; Zhu, Jingtao; Ma, Xiaoying; Li, Haochuan; Wang, Hongchang; Sawhney, Kawal J S; Wang, Zhanshan

2012-05-01

252

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

253

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

254

Early Time Points Perfusion Imaging: Theoretical Analysis of Correction Factors for relative cerebral blood flow Estimation Given Local Arterial Input Function  

PubMed Central

If local arterial input function (AIF) could be identified, we present a theoretical approach to generate a correction factor based on local AIF for the estimation of relative cerebral blood flow (rCBF) under the framework of early time points perfusion imaging (ET). If C(t), the contrast agent bolus concentration signal time course, is used for rCBF estimation in ET, the correction factor for C(t) is the integral of its local AIF. The recipe to apply the correction factor is to divide C(t) by the integral of its local AIF to obtain the correct rCBF. By similar analysis, the correction factor for the maximum derivative (MD1) of C(t) is the maximum signal of AIF and the correction factor for the maximum second derivative (MD2) of C(t) is the maximum derivative of AIF. In the specific case of using normalized gamma-variate function as a model for AIF, the correction factor for C(t) (but not for MD1) at the time to reach the maximum derivative is relatively insensitive to the shape of the local AIF.

Kwong, Kenneth K.; Chesler, David A.

2011-01-01

255

Shear Correction Factors in Creep-Damage Analysis of Beams, Plates and Shells  

Microsoft Academic Search

Modern design rules for thin-walled structures which operate at elevated temperatures are based on the demand that the creep and may be the damage behaviour should be taken into account. In the last four decades various models including the scalar or tensor valued hardening and damage variables are established. These models reflect the influence of the deformation or the damage

Holm Altenbach; Konstantin Naumenko

2002-01-01

256

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

257

Static shunt compensation for voltage flicker reduction and power factor correction  

Microsoft Academic Search

It is shown that a static VAR generator comprising a capacitive filter network and a thyristor-controlled inductor can effectively compensate for rapid and unbalanced load variations and is able to maintain system voltage and power factor, even under extremely adverse load conditions. The performance of such a static compensating system is, however, dependent on the principles of control employed, the

L. Gyugyi; R. A. Otto

1976-01-01

258

Power Factor Correction Based on Transmission Loss Minimization with Uncertain Source Harmonics and Load Characteristics  

Microsoft Academic Search

This article presents a method of reducing the expected value of the transmission loss for a specified range of source impedance values at different buses by using inductor-capacitor compensators where it is desired to maintain a given power factor at a specified value. The criterion is based on mean value estimation of source and load characteristics, which is enabled by

O. M. Aloquili; A. F. Zobaa; H. H. Zeineldin

2009-01-01

259

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

260

A new UPS scheme provides harmonic suppression and input power factor correction  

Microsoft Academic Search

A new parallel processing uninterruptible power supply (UPS) configuration is proposed in this paper. It provides active power line conditioning to minimize mains current distortion. This performance is superior to a conventional UPS. A prototype has been implemented and tested to verify its performance. The experimental results show that the input power factor of the proposed UPS is nearly unity,

Jinn-Chang Wu; Hurng-Liahng Jou

1995-01-01

261

Temperature  

NSDL National Science Digital Library

Thermometers record the temperature in a given location. Temperature is a non-living thing because it doesn't physically move or eat, for example. However, temperature is a very important factor that effects where animals live and how long they stay in that particular spot.

Luis Miguel Orta Rial (None;)

2008-03-24

262

Scattering amplitudes and static atomic correction factors for the composition-sensitive 002 reflection in sphalerite ternary III-V and II-VI semiconductors  

NASA Astrophysics Data System (ADS)

Scattering amplitudes taking into account the redistribution of charge due to bonds and corresponding correction factors considering the effect of static atomic displacements were computed using density functional theory and the empirical Keating model for ternary III-V and II-VI semiconductors in different strain states. Polynomials were fitted to the scattering amplitudes and the correction factors as a function of the composition of the ternary semiconductors.

Schowalter, M.; Mueller, K.; Rosenauer, A.

2012-01-01

263

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

264

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

PubMed

The objective of the present study was to determine the presence of risk factors for the occurrence of neural tube defects. Data for 33,535 births which occurred at Hospital do Servidor Público Estadual de São Paulo from July 1973 to December 1986 were collected in a prospective manner as recommended by "Estudo Colaborativo Latino-Americano de Malformações Congênitas" (ECLAMC, Collaborative Latin American Study on Congenital Malformations). Twenty-six cases of neural tube defects were detected (0.77/1000 births). Of these, 11 were cases of spina bifida (0.39/1000 births), 9 of anencephaly (0.27/1000 births) and 6 of encephalocele (0.18/1000 births). We observed a higher frequency of polyhydramnios, premature labor, Apgar scores of less than 7 at the first and fifth minutes, low birth weight and intrauterine growth retardation. PMID:1341003

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

265

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; Onar, Omer C [ORNL; Miller, John M [ORNL; Tang, Lixin [ORNL

2013-01-01

266

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

267

On the Correction Factors Affecting the Evaluation of the Beta Total Radioactivity of Fission Products; SUR LES FACTEURS DE CORRECTION AFFECTANT L'EVALUATION DE LA RADIOACTIVITE BETA TOTALE DES PRODUITS DE FISSION  

Microsoft Academic Search

Data are presented which make possible the precise evaluation of the ; BETA activity of fission products measured in a variety of conditions of ; absorption and self-absorption. The correction factors to apply to the BETA ; measurement of fission products when the counter has been standardized wlth ; potassium-40 or with thallium-204, are tabulated. Nomograms for computing self-; absorption

P. Gaglione; E. Van der Stricht

1963-01-01

268

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

269

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

270

Temperature gradient mechanism: Overview of the multiple pass controlling factors  

Microsoft Academic Search

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

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

2010-01-01

271

Root physiological factors involved in cool-season grass response to high soil temperature  

Microsoft Academic Search

High soil temperature is a critical factor limiting growth of cool-season grasses. This study was designed to examine changes in water, nutritional, and hormonal status in response to high soil temperature for creeping bentgrass (Agrostis stoloniferavar. palustris) and to compare the sensitivity of those parameters to high soil temperatures. Plants of ‘Penncross’ were exposed to 35°C soil temperature (heat stress)

Xiaozhong Liu; Bingru Huang

2005-01-01

272

Mutual correction of faulty PCNA subunits in temperature-sensitive lethal mus209 mutants of Drosophila melanogaster.  

PubMed Central

Proliferating cell nuclear antigen (PCNA) functions in DNA replication as a processivity factor for polymerases delta and epsilon, and in multiple DNA repair processes. We describe two temperature-sensitive lethal alleles (mus209(B1) and mus209(2735)) of the Drosophila PCNA gene that, at temperatures permissive for growth, result in hypersensitivity to DNA-damaging agents, suppression of position-effect variegation, and female sterility in which ovaries are underdeveloped and do not produce eggs. We show by mosaic analysis that the sterility of mus209(B1) is partly due to a failure of germ-line cells to proliferate. Strikingly, mus209(B1) and mus209(2735) interact to restore partial fertility to heteroallelic females, revealing additional roles for PCNA in ovarian development, meiotic recombination, and embryogenesis. We further show that, although mus209(B1) and mus209(2735) homozygotes are each defective in repair of transposase-induced DNA double-strand breaks in somatic cells, this defect is substantially reversed in the heteroallelic mutant genotype. These novel mutations map to adjacent sites on the three-dimensional structure of PCNA, which was unexpected in the context of this observed interallelic complementation. These mutations, as well as four others we describe, reveal new relationships between the structure and function of PCNA.

Henderson, D S; Wiegand, U K; Norman, D G; Glover, D M

2000-01-01

273

Temperature: The "Ignored" Factor at the NanoBio Interface.  

PubMed

Upon incorporation of nanoparticles (NPs) into the body, they are exposed to biological fluids, and their interaction with the dissolved biomolecules leads to the formation of the so-called protein corona on the surface of the NPs. The composition of the corona plays a crucial role in the biological fate of the NPs. While the effects of various physicochemical parameters on the composition of the corona have been explored in depth, the role of temperature upon its formation has received much less attention. In this work, we have probed the effect of temperature on the protein composition on the surface of a set of NPs with various surface chemistries and electric charges. Our results indicate that the degree of protein coverage and the composition of the adsorbed proteins on the NPs' surface depend on the temperature at which the protein corona is formed. Also, the uptake of NPs is affected by the temperature. Temperature is, thus, an important parameter that needs to be carefully controlled in quantitative studies of bionano interactions. PMID:23808533

Mahmoudi, Morteza; Abdelmonem, Abuelmagd M; Behzadi, Shahed; Clement, Joachim H; Dutz, Silvio; Ejtehadi, Mohammad R; Hartmann, Raimo; Kantner, Karsten; Linne, Uwe; Maffre, Pauline; Metzler, Scott; Moghadam, Mojhgan K; Pfeiffer, Christian; Rezaei, Meisam; Ruiz-Lozano, Pilar; Serpooshan, Vahid; Shokrgozar, Mohammad A; Nienhaus, G Ulrich; Parak, Wolfgang J

2013-07-10

274

Study of aging characteristics of generator stator insulation based on temperature spectrum of dielectric dissipation factor  

Microsoft Academic Search

In this paper, accelerated multi-factor aging tests in laboratory have been conducted on the stator bars of a large generator. During the period of aging, the temperature spectra of dielectric dissipation factor tan ? of stator insulation were employed to investigate aging characteristics of insulation materials. Test results showed that the peak temperature Tm of the tan ? -T curve

Xiaoqin Ma; Xiaowei Ma; Bo Yue; Weisheng Lu; Hengkun Xie

2003-01-01

275

Relativistic Free-Free Gaunt Factors for High-Temperature Stellar Plasmas  

NASA Astrophysics Data System (ADS)

The free-free Gaunt factor of the dense high-temperature stellar plasma is calculated by using the accurate relativistic cross section and is compared with the Gaunt factor derived by using Sommerfeld's exact nonrelativistic cross section. A wide range of electron degeneracy is accurately taken into account. Significant deviations are found for high-temperature cases. Key words: ATOMIC PROCESSES-OPACITIES

Itoh, N.

1992-03-01

276

PHYSICOCHEMICAL FACTORS AFFECTING TOXICITY IN FRESHWATER: HARDNESS, PH, AND TEMPERATURE  

EPA Science Inventory

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. uch of the disparity among results reported in the literature was caused by improperly des...

277

Temperature regulation of virulence factors in the pathogen Vibrio coralliilyticus  

Microsoft Academic Search

Sea surface temperatures (SST) are rising because of global climate change. As a result, pathogenic Vibrio species that infect humans and marine organisms during warmer summer months are of growing concern. Coral reefs, in particular, are already experiencing unprecedented degradation worldwide due in part to infectious disease outbreaks and bleaching episodes that are exacerbated by increasing SST. For example, Vibrio

Nikole E Kimes; Christopher J Grim; Wesley R Johnson; Nur A Hasan; Ben D Tall; Mahendra H Kothary; Hajnalka Kiss; A Christine Munk; Roxanne Tapia; Lance Green; Chris Detter; David C Bruce; Thomas S Brettin; Rita R Colwell; Pamela J Morris

2012-01-01

278

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

Microsoft Academic Search

A variety of reptiles possess temperature-dependent sex determination (TSD) in which the incubation temperature of a developing egg determines the gonadal sex. Current evidence suggests that temperature signals may be transduced into steroid hormone signals with estrogens directing ovarian differentiation. Steroidogenic factor 1 (SF-1) is one component of interest because it regulates the expression of steroidogenic enzymes in mammals and

Alice Fleming; Thane Wibbels; James K Skipper; David Crews

1999-01-01

279

Effect of Factors Affecting Fracture Energy of Asphalt Concrete at Low Temperature  

Microsoft Academic Search

Low temperature cracking is considered one of the primary distress modes of asphalt pavements built in northern climates. The detrimental effects of low-temperature cracking of asphalt pavements have motivated new work in fracture testing of hot-mix asphalt (HMA). A comprehensive study was conducted to investigate the effect of various factors on the fracture resistance of asphalt mixtures at low temperatures.

Xinjun Li; Andrew F. Braham; Mihai O. Marasteanu; William G. Buttlar; R. Christopher Williams

2008-01-01

280

Logarithmic Corrections to the Landau Specific Heat near the Curie Temperature of the Dipolar Ising Ferromagnet LiTbF4  

Microsoft Academic Search

Quantitative experimental results for the logarithmic corrections to the Landau specific heat are reported for the dipolar Ising ferromagnet LiTbF4 near its Curie temperature Tc=2.885 K. The power of the leading logarithmic term is found to be 0.34+\\/-0.03, and the corresponding amplitude ratio is 0.24+\\/-0.01. These results are in agreement with the predicted values of 13 and 1\\/4 , respectively.

Guenter Ahlers; Avinoam Kornblit; H. J. Guggenheim

1975-01-01

281

Temperature and risk factors for ischaemic heart disease in the Caerphilly prospective study  

Microsoft Academic Search

OBJECTIVE--To examine the associations between air temperature and risk factors for ischaemic heart disease. METHOD--Data on risk factors are available from up to 2036 men in the Caerphilly Prospective Heart Disease Study. Daily temperatures were obtained from the Meteorological Office. Relations between these were examined by regression. RESULTS--The coldest month of the year has a mean temperature that is 16

P C Eldwood; A Beswick; J R OBrien; S Renaud; R Fifield; E S Limb; D Bainton

1993-01-01

282

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

283

Period-doubling bifurcation in two-stage power factor correction converters using the method of incremental harmonic balance and Floquet theory  

NASA Astrophysics Data System (ADS)

In this paper, period-doubling bifurcation in a two-stage power factor correction converter is analyzed by using the method of incremental harmonic balance (IHB) and Floquet theory. A two-stage power factor correction converter typically employs a cascade configuration of a pre-regulator boost power factor correction converter with average current mode control to achieve a near unity power factor and a tightly regulated post-regulator DC—DC Buck converter with voltage feedback control to regulate the output voltage. Based on the assumption that the tightly regulated post-regulator DC—DC Buck converter is represented as a constant power sink and some other assumptions, the simplified model of the two-stage power factor correction converter is derived and its approximate periodic solution is calculated by the method of IHB. And then, the stability of the system is investigated by using Floquet theory and the stable boundaries are presented on the selected parameter spaces. Finally, some experimental results are given to confirm the effectiveness of the theoretical analysis.

Wang, Fa-Qiang; Zhang, Hao; Ma, Xi-Kui

2012-02-01

284

FACTORS AFFECTING SOIL RESPIRATION IN REFERENCE WITH TEMPERATURE' S ROL E IN THE GLOBAL SCAL E  

Microsoft Academic Search

Soil respiration is CO2 evolution process from soil to at mosp here , mainly produced by soil micro2organism and plant roots. It is affected not only by biological factors (vegetation , micro2or2 ganism , etc. ) and environmental factors ( temperature , moisture , p H , etc. ) , but also more and more strongly by man2made factors. Based

Liu Shaohui; Zhao Kun

285

Factors affecting the performance of metakaolin geopolymers exposed to elevated temperatures  

Microsoft Academic Search

The effects of geopolymer binder systems exposed to elevated temperatures are examined. Geopolymers investigated were synthesized\\u000a from metakaolin, activated by combinations of sodium\\/potassium silicate and sodium\\/potassium hydroxide. The specimens were\\u000a then exposed to temperatures of 800 °C. The factors studied were: (1) calcining temperatures of kaolin; (2) Si\\/Al ratio of\\u000a the geopolymer; (3) activator\\/metakaolin ratio; (4) curing temperature; and (5) alkali

Daniel L. Y. Kong; Jay G. Sanjayan; Kwesi Sagoe-Crentsil

2008-01-01

286

Monte Carlo calculations of monoenergetic electron depth dose distributions in LiF chips: Skin dose correction factors for beta rays  

SciTech Connect

Monte Carlo calculations have been carried out for monoenergetic electrons from 0.1 to 4 MeV irradiating LiF chips in both perpendicular and isotropic geometry. This enabled the calculation of skin dose correction factors (beta factors) for typical beta energy spectra as measured with a beta-ray spectrometer at CANDU nuclear generating stations. The correction factors were estimated by averaging the depth dose distributions for the monoenergetic electrons over the experimentally measured beta-ray spectra. The calculations illustrate the large uncertainty in beta factors arising from the unknown angular distribution of the beta-ray radiation field and uncertainties in the shape of the beta-ray spectra below 500 keV. 28 refs., 8 figs., 2 tabs.

Horowitz, Y.S. [Ben Gurion Univ. of the Negev, Beersheva (Israel); Hirning, C.R. [Ontario Hydro, Whitby (Canada); Yuen, P.; Wong, P. [Chalk River Labs., Ontario (Canada)

1994-10-01

287

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

288

Power Factor Correction at MIT-Bates Linear Accelerator Center with Pulsed Loads of up to 180 MW Peak (2.7 MW Average)  

NASA Astrophysics Data System (ADS)

Recent changes in electrical loads at MIT-Bates have increased power levels and energy usage while adversely affecting the overall power factor of the facility. The latest contract for power and energy calls for MIT-Bates to pay for power factors lower than 0.9 lagging. A study revealed that power factor correction equipment could reduce our energy costs by about 10 %. Due to the fact that MIT-Bates has 12 pulsed klystron loads that operate at varied repetition rates and pulse widths, it was determined that the power factor correction would be best done at the 23 kV level of the incoming line rather than at the 480 V level. Additional design concerns required that a study of operating conditions at the 23 kV level be performed to verify that the harmonics developed as a result of the pulsed nature of the MIT-Bates transmitter loads were reasonable. This report describes the measurements taken and the resulting power factor correction system design. The pay back time of the designed, constructed, and installed equipment is calculated to be less than 9 months under normal operating levels. The equipment will be installed in 1997.

Averill, R.; Sibley, C.; Hatch, K.; Gross, R.

1997-05-01

289

High School 9th Grade Students' Understanding Level and Misconceptions about Temperature and Factors Affecting It  

ERIC Educational Resources Information Center

|The purpose of this study is to explore students' understanding levels and misconceptions about temperature and factors affecting it. The concept of the study was chosen from Geography National Curriculum. In this study, a questionnaire was developed after a pilot study with an aim to ascertain the students' understanding levels of temperature

Akbas, Yavuz

2012-01-01

290

Air density correction in ionization dosimetry  

Microsoft Academic Search

Air density must be taken into account when ionization dosimetry is performed with unsealed ionization chambers. The German dosimetry protocol DIN 6800-2 states an air density correction factor for which current barometric pressure and temperature and their reference values must be known. It also states that differences between air density and the attendant reference value, as well as changes in

G. Christ; O. S. Dohm; E. Schüle; S. Gaupp; M. Martin

2004-01-01

291

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

NASA Astrophysics Data System (ADS)

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 ?m, and the dual-angle (DA) method, using one single channel (11 ?m) at two observation angles (close to nadir and around 55° forward). The ground LST measurements were performed in a large, flat, and thermally homogeneous area of rice fields during the summers of 2002-2005, when the crop showed full vegetation cover. A total of 23 concurrences of ground measurements and AATSR data were obtained. Results showed that the SW algorithms worked satisfactorily provided that the characteristics of the area are correctly prescribed, either through the classification of the land cover type and vegetation cover fraction or with the surface emissivity. In this case the AATSR-derived LSTs agreed with the ground LSTs within ±1.0°C for all the data of the comparison, with negligible average bias and a standard deviation of 0.5°C. The DA algorithms were less accurate than the SW algorithms for the data used in this study, yielding standard deviations of 1.0°C.

Coll, CéSar; Caselles, Vicente; Galve, Joan M.; Valor, Enric; Niclòs, Raquel; SáNchez, Juan M.

2006-06-01

292

Temperature-dependent Debye-Waller factors for semiconductors with the wurtzite-type structure.  

PubMed

We computed Debye-Waller factors in the temperature range from 0.1 to 1000 K for AlN, GaN, InN, ZnO and CdO with the wurtzite-type structure. The Debye-Waller factors were derived from phonon densities of states obtained from Hellmann-Feynman forces computed within the density-functional-theory formalism. The temperature dependences of the Debye-Waller factors were fitted and fit parameters are given. PMID:19349666

Schowalter, M; Rosenauer, A; Titantah, J T; Lamoen, D

2009-03-13

293

Do current models correctly predict the L-band terrestrial brightness temperature when crops begin to senesce?  

Technology Transfer Automated Retrieval System (TEKTRAN)

The microwave terrestrial brightness temperature is sensitive to soil moisture, the water content of the first few centimeters of Earth's surface. The European Space Agency will soon launch the Soil Moisture and Ocean Salinity (SMOS) mission, the world's first soil moisture satellite that will measu...

294

Atmospheric correction of infrared measurements of sea surface temperature using channels at 3.7, 11 and 12 Mum  

Microsoft Academic Search

Atmospheric effects upon the radiometric determination of surface temperature were studied for channels centered at 3.7, 11 and 12 Mum. The error due to the atmosphere is least for the channel centered at 3.7 Mum, which is a real advantage. The use of a linear combination of two or all three of these channels allows one to eliminate most of

P. Y. Deschamps; T. Phulpin

1980-01-01

295

Effect of temperature on growth of Vibrio parahaemolyticus [corrected] and Vibrio vulnificus in flounder, salmon sashimi and oyster meat.  

PubMed

Vibrio parahaemolyticus and Vibrio vulnificus are the major pathogenic Vibrio species which contaminate ready-to-eat seafood. The purpose of this study was to evaluate the risk of human illness resulting from consumption of ready-to-eat seafood such as sashimi and raw oyster meat due to the presence of V. parahaemolyticus and V. vulnificus. We compared the growth kinetics of V. parahaemolyticus and V. vulnificus strains in broth and ready-to-eat seafood, including flounder and salmon sashimi, as a function of temperature. The growth kinetics of naturally occurring V. vulnificus in raw oyster meat was also evaluated. The minimum growth temperatures of V. parahaemolyticus and V. vulnificus in broth were 13 °C and 11 °C, respectively. Overall, significant differences in lag time (LT) and specific growth rate (SGR) values between flounder and salmon sashimi were observed at temperatures ranging from 13 °C to 30 °C (p < 0.05). The growth of naturally occurring V. vulnificus reached stationary phase at ~4 log CFU/g in oysters, regardless of the storage temperature. This data indicates that the population of V. vulnificus in oysters did not reach the maximum population density as observed in the broth, where growth of V. vulnificus and V. parahaemolyticus isolated from oysters grew up to >8 log CFU/mL. PMID:23330227

Kim, Yoo Won; Lee, Soon Ho; Hwang, In Gun; Yoon, Ki Sun

2012-12-01

296

Finite Temperature Correction to the Mobility of the Strongly Damped Sine-Gordon Soliton —Effect of the Frequency Cut-Off—  

NASA Astrophysics Data System (ADS)

The mobility of the damped sine-Gordon soliton with the damping constant \\varGamma is calculated up to the first order in temperature in the presence of the frequency cut-off ?c in the spectrum of the heat bath. The first order finite temperature correction turns out to be different in the two limiting cases: (I) ?c??, \\varGamma?? with ?c/\\varGamma?0 and (II) ?c??, \\varGamma?? with ?c/\\varGamma??. It is also found that the first limit corresponds to the mobility of the overdamped sine-Gordon model without inertia calculated by Kaup and the second to that of the heavily damped limit of the damped sine Gordon model with inertia calculated by Kaup and Osman both assuming the white noise spectrum. Our result gives the physical interpretation of the discrepancy between these two calculations.

Hida, Kazuo

1986-11-01

297

Conditional intercellular cohesion in a Dictyostelium discoideum mutant which is temperature sensitive for correct processing of asparagine-linked oligosaccharides.  

PubMed

Mutants of Dictyostelium discoideum have been isolated by a selection for cells with temperature-sensitive defects in the maturation of glycoprotein N-linked oligosaccharides. Here we describe a mutant, HT7, which is unable to aggregate at the restrictive temperature, but which aggregates and makes fruiting bodies at the permissive temperature. HT7 shows normal early developmental intercellular cohesion, but is temperature sensitive for expression of the ethylenediamine-tetraacetic acid (EDTA)-resistant cohesion characteristic of aggregation. The mutant initiates aggregation, but forms only loose cell mounds which later disperse. Metabolic labelling studies indicate that the thermolabile defect is not in protein synthesis, assembly of the lipid-linked precursor of N-linked oligosaccharides or transfer of the precursor to proteins. However, the defect does prevent assembly of fully processed N-linked oligosaccharides. Further, two glycopeptides, obtained from exhaustive Pronase digests of wild-type plasma membrane glycoproteins, inhibit intercellular cohesion of aggregation-stage wild-type cells. HT7 produces only approximately 50% of the wild-type level of these glycopeptides at the restrictive temperature and one of the glycopeptides has reduced cohesion inhibition ability. A revertant of HT7 was found to aggregate normally, to have restored EDTA-resistant cohesion, to have normal profiles of N-linked oligosaccharides and to express the two cohesion-inhibiting glycopeptides normally. These data strongly support a model in which cohesion during late aggregation is at least in part due to recognition between surface glycans and receptors on neighbouring cells. PMID:1665373

Boose, J A; Henderson, E J

1991-06-01

298

Compact electromagnetic induction-heated fluid energy utilization system using voltage-fed resonant PWM inverter with power factor correction scheme  

Microsoft Academic Search

This paper presents a novel prototype of a new conceptual electromagnetic induction fluid heating appliance using a series capacitor-compensated load resonant high-frequency inverter with a phase-shifted PWM and a power factor correction scheme. Its operating characteristics in steady-state are illustrated and evaluated on the basis of its computer simulation and experimental results. The promising cost effective application of this electromagnetic

K. Ogasawara; K. D. G. Laknath; S. Watanabe; M. Nakaoka; Y. Uchihori

1996-01-01

299

Changes in Plasma Atrial Natriuretic Factor during Sequential Fluid Removal and Biochemical Correction in End-Stage Chronic Renal Failure Patients  

Microsoft Academic Search

Plasma immunoreactive atrial natriuretic factor (ANF) levels, their chromatographic profiles (high-performance liquid chromatography; HPLC) and changes during sequential ultrafiltration (UF; 1 litre\\/h) and biochemical correction without fluid removal (BC; 3 h) were studied in 8 end-stage chronic renal failure patients on intermittent haemodialysis ( > 1 year). Patients entered randomly the UF-BC or BC-UF protocols that were reversed after 1

G. Tonolo; M. McMillan; A. M. Richards; P. Montorsi; J. Polonia; A. Soro; C. Troffa; N. Glorioso

1990-01-01

300

An improved control algorithm of shunt active filter for voltage regulation, harmonic elimination, power-factor correction, and balancing of nonlinear loads  

Microsoft Academic Search

This paper deals with an implementation of a new control algorithm for a three-phase shunt active filter to regulate load terminal voltage, eliminate harmonics, correct supply power-factor, and balance the nonlinear unbalanced loads. A three-phase insulated gate bipolar transistor (IGBT) based current controlled voltage source inverter (CC-VSI) with a DC bus capacitor is used as an active filter (AF). The

Ambrish Chandra; Bhim Singh; B. N. Singh; Kamal Al-Haddad

2000-01-01

301

Determination of the Kwall correction factor for a cylindrical ionization chamber to measure air-kerma in 60Co gamma beams  

Microsoft Academic Search

The factor Kwall to correct for photon attenuation and scatter in the wall of ionization chambers for 60Co air-kerma measurement has been traditionally determined by a procedure based on a linear extrapolation of the chamber current to zero wall thickness. Monte Carlo calculations by Rogers and Bielajew (1990 Phys. Med. Biol.35 1065–78) provided evidence, mostly for chambers of cylindrical and

R F Laitano; M P Toni; M Pimpinella; M Bovi

2002-01-01

302

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

303

Factors affecting the ability of energy functions to discriminate correct from incorrect folds 1 1 Edited by F. E. Cohen  

Microsoft Academic Search

Eighteen low and medium resolution empirical energy functions were tested for their ability to distinguish correct from incorrect folds from three test sets of decoy protein conformations. The energy functions included 13 pairwise potentials of mean force, covering a wide range of functional forms and methods of parameterization, four potentials that attempt to detect properly formed hydrophobic cores, and one

Britt H. Park; Enoch S. Huang; Michael Levitt

1997-01-01

304

Accuracy of Spencer-Attix cavity theory and calculations of fluence correction factors for the air kerma formalism  

SciTech Connect

EGSnrc calculations of ion chamber response and Spencer-Attix (SA) restricted stopping-power ratios are used to test the assumptions of the SA cavity theory and to assess the accuracy of this theory as it applies to the air kerma formalism for {sup 60}Co beams. Consistent with previous reports, the EGSnrc calculations show that the SA cavity theory, as it is normally applied, requires a correction for the perturbation of the charged particle fluence (K{sub fl}) by the presence of the cavity. The need for K{sub fl} corrections arises from the fact that the standard prescription for choosing the low-energy threshold {Delta} in the SA restricted stopping-power ratio consistently underestimates the values of {Delta} needed if no perturbation to the fluence is assumed. The use of fluence corrections can be avoided by appropriately choosing {Delta}, but it is not clear how {Delta} can be calculated from first principles. Values of {Delta} required to avoid K{sub fl} corrections were found to be consistently higher than {Delta} values obtained using the conventional approach and are also observed to be dependent on the composition of the wall in addition to the cavity size. Values of K{sub fl} have been calculated for many of the graphite-walled ion chambers used by the national metrology institutes around the world and found to be within 0.04% of unity in all cases, with an uncertainty of about 0.02%.

La Russa, D. J.; Rogers, D. W. O. [Ottawa Carleton Institute of Physics, Carleton University Campus, Ottawa, Ontario K1S 5B6 (Canada)

2009-09-15

305

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

306

Experimental determination of the effective point of measurement and the displacement correction factor for cylindrical ionization chambers in a 6 MV photon beam  

NASA Astrophysics Data System (ADS)

The displacement effect of cylindrical ionization chambers is taken into account either by an effective point of measurement (EPOM) or, alternatively, by using a displacement correction factor. The dependence of these effects on water was examined as a function of the cavity radius for 60Co gamma radiation in a previous paper. This paper describes results for high-energy photon beams using the same measurement technique. Additionally, the displacement correction factor was directly measured. Absorbed doses measured under reference conditions following the international protocol IAEA TRS-398 and the German protocol DIN 6800-2 agreed well between the chambers with different cavity radii within a standard uncertainty of 0.2%. However, there was a constant difference of 0.2% between both protocols. Similar to our observations made in 60Co, absorbed doses measured with the different chambers at depths beyond the maximum showed deviations of up to 0.6% and 0.5% for IAEA TRS-398 and DIN 6800-2, respectively, and deviations of more than 1% were found for both protocols in the build-up and maximum region. We therefore propose modified formulas for the determination of the EPOM and the displacement correction factor.

Legrand, C.; Hartmann, G. H.; Karger, C. P.

2012-11-01

307

A comprehensive analysis of the role of correction factors in the allometric predictivity of clearance from rat, dog, and monkey to humans.  

PubMed

This study was conducted to comprehensively evaluate the performance of various allometric scaling methods for the prediction of human clearance. Allometric scaling was used to predict clearance for 103 compounds, for which clearance data in the rat, dog, monkey, and humans were available. Allometry was performed using all three preclinical species and with combinations of any two species. The methods employed included standard allometry and various correction factors, including brain weight, maximum lifespan potential, and glomerular filtration. Scaling was performed on all compounds universally and on segregated subsets based on allometric exponent, clearance, physicochemical property, or route of elimination. 776 allometric combinations with 27,313 individual outcomes were performed. A predicted-to-observed clearance ratio of 0.5 to twofold was preselected as the criterion for predictive success. The success rate of allometric scaling ranged from 18 to 53%; none of the correction factors resulted in substantially improved predictivity. Furthermore, none of the methods attempted in this study achieved a success rate greater than that observed by simply estimating human clearance based on monkey hepatic extraction. Prospective allometric scaling, with or without correction factors, represents a suboptimal technique for estimating human clearance based on in vivo preclinical data. PMID:15349961

Nagilla, Rakesh; Ward, Keith W

2004-10-01

308

Correction to the Metal-Insulator Transition Temperature due to Cation Size and Strain Effects for Colossal Magnetoresistance Perovskites  

Microsoft Academic Search

A phenomenological expression of the metal-insulator transition temperature is proposed for AMnO3 manganese perovskites by taking into account the distortion of the Mn-O-Mn bond due to A-cation size and the strain-dependent effect due to performed Jahn-Teller distortions, independently. Using reasonable physical parameters, the calculated results give excellent agreement with experimental data obtained in polycrystalline samples of La2\\/3(Ca1- xBax)1\\/3MnO3, providing a

Song-Liu Yuan; Jie Liu; Zheng-Cai Xia; Gang Peng; Jie Tang; Guo-Hong Zhang; Li-Jiang Zhang; Wen Feng; Zhong-Yi Li; Ying-Ping Yang; Li Liu; Cao-Shui Xiong

2002-01-01

309

Finite-temperature corrections to the time-domain equations of motion for perpendicular propagation in nonuniform magnetized plasmas  

SciTech Connect

In this paper we extend the new techniques of W. Tierens and D. D. Zutter, J. Comput. Phys. 231, 5144 (2012) to include finite Larmor radius effects up to second order in the Larmor radius. We limit ourselves to the case of propagation perpendicular to the background magnetic field B(vector sign){sub 0}. We show that our time-domain technique is able to produce the lowest-order Bernstein wave (a wave believed to be useful for heating fusion devices [H. P. Laqua, Plasma Phys. Controlled Fusion 49, R1 (2007)]). The discrete equations retain many of the favourable properties described in W. Tierens and D. D. Zutter, J. Comput. Phys. 231, 5144 (2012), i.e., unconditional stability and a straightforward relation between the second-order accurate continuous dispersion relation and the dispersion relation of the discretized problem. The theory is illustrated by a place-independent and a place-dependent temperature numerical example.

Tierens, W.; De Zutter, D. [Department of Information Technology, Ghent University, Sint-Pietersnieuwstraat 41, Ghent (Belgium)

2012-11-15

310

Finite-temperature corrections to the time-domain equations of motion for perpendicular propagation in nonuniform magnetized plasmas  

NASA Astrophysics Data System (ADS)

In this paper we extend the new techniques of W. Tierens and D. D. Zutter, J. Comput. Phys. 231, 5144 (2012) to include finite Larmor radius effects up to second order in the Larmor radius. We limit ourselves to the case of propagation perpendicular to the background magnetic field Bvec 0. We show that our time-domain technique is able to produce the lowest-order Bernstein wave (a wave believed to be useful for heating fusion devices [H. P. Laqua, Plasma Phys. Controlled Fusion 49, R1 (2007)]). The discrete equations retain many of the favourable properties described in W. Tierens and D. D. Zutter, J. Comput. Phys. 231, 5144 (2012), i.e., unconditional stability and a straightforward relation between the second-order accurate continuous dispersion relation and the dispersion relation of the discretized problem. The theory is illustrated by a place-independent and a place-dependent temperature numerical example.

Tierens, W.; De Zutter, D.

2012-11-01

311

Stress Intensity Factors for Woven Glass\\/Epoxy Laminates with Cracks at Cryogenic Temperatures  

Microsoft Academic Search

We investigate the stress intensity factors for several crack configurations in G-11 woven glass\\/epoxy laminates with temperature-dependent properties under tension at cryogenic temperatures. A state of generalized plane strain is assumed. Cracks are assumed to have occurred in the transverse fiber bundles. Cases of a single stack and doubly-periodic arrays of cracks are considered. The order of stress singularities at

TOMO TAKEDA; YASUHIDE SHINDO; FUMIO NARITA; KAZUAKI SANADA

2004-01-01

312

Exchange interactions and local-moment fluctuation corrections in ferromagnets at finite temperatures based on noncollinear density-functional calculations  

NASA Astrophysics Data System (ADS)

We explore the derivation of interatomic exchange interactions in ferromagnets within density-functional theory (DFT) and the mapping of DFT results onto a spin Hamiltonian. We delve into the problem of systems comprising atoms with strong spontaneous moments together with atoms with weak induced moments. All moments are considered as degrees of freedom, with the strong moments thermally fluctuating only in angle and the weak moments thermally fluctuating in angle and magnitude. We argue that a quadratic dependence of the energy on the weak local moments magnitude, which is a good approximation in many cases, allows for an elimination of the weak-moment degrees of freedom from the thermodynamic expressions in favor of a renormalization of the Heisenberg interactions among the strong moments. We show that the renormalization is valid at all temperatures accounting for the thermal fluctuations and resulting in temperature-independent renormalized interactions. These are shown to be the ones directly derived from total-energy DFT calculations by constraining the strong-moment directions, as is done, e.g., in spin-spiral methods. We furthermore prove that within this framework the thermodynamics of the weak-moment subsystem, and in particular all correlation functions, can be derived as polynomials of the correlation functions of the strong-moment subsystem with coefficients that depend on the spin susceptibility and that can be calculated within DFT. These conclusions are rigorous under certain physical assumptions on the measure in the magnetic phase space. We implement the scheme in the full-potential linearized augmented plane wave method using the concept of spin-spiral states, considering applicable symmetry relations and the use of the magnetic force theorem. Our analytical results are corroborated by numerical calculations employing DFT and a Monte Carlo method.

Ležai?, Marjana; Mavropoulos, Phivos; Bihlmayer, Gustav; Blügel, Stefan

2013-10-01

313

Temperature effect on the 002 structure factor of ternary Ga1-xInxAs crystals  

NASA Astrophysics Data System (ADS)

In this work, we study the effect of relaxation of the atomic positions and lattice parameter of mixed Ga1-xInxAs systems on the 002 electron atomic scattering amplitudes (ASA). The ASAs are shown to vary strongly with lattice parameter but to be indistinguishable for different In concentrations when the lattice parameter is held fixed. The resulting relationship between ASA and lattice parameter is then used in a finite temperature, zero pressure Monte Carlo relaxation of the mixed crystal. The consequence of the use of this atomic scattering amplitude is a reduction of the structure factor, leading to an increase of the In concentration at which the 002 structure factor vanishes. This method directly includes the effect of temperature on the ASA and on the structure factors and therefore does not require an explicit knowledge of the Debye-Waller factor.

Titantah, J. T.; Lamoen, D.; Schowalter, M.; Rosenauer, A.

2007-08-01

314

Evaluation of weldment creep and fatigue strength-reduction factors for elevated-temperature design  

Microsoft Academic Search

New explicit weldment strength criteria in the form of creep and fatigue strength-reduction factors were recently introduced into the American Society of Mechanical Engineers Code Case N-47, which governs the design of elevated-temperature nuclear plants components in the United States. This paper provides some of the background and logic for these factors and their use, and it describes the results

Corum

1989-01-01

315

The role of demagnetization factor in determining the ‘true’ value of the Curie temperature  

SciTech Connect

The Curie temperature, T{sub c}, is the temperature above which a material loses its long-range ferromagnetic order. Considering the equation of state of a ferromagnet in the mean-field approximation it has been shown theoretically that the value of the demagnetization factor N has a significant influence on the perceived location of T{sub c} on the temperature scale. A series of precise measurements of magnetization using two differently shaped single crystals of high-purity gadolinium was carried out to prove this result experimentally and develop a procedure leading to the 'true' value of T{sub c}.

Zverev, V.I.; Gimaev, R.R.; Tishin, A.M.; Mudryk, Ya; Gschneidner, Jr., K.A.; Pecharsky, V.K.

2011-05-20

316

Temperature: a prolonged confounding factor on cholinesterase activity in the tropical reef fish Acanthochromis polyacanthus.  

PubMed

Cholinesterase activity usually decreases in fish exposed to anticholinesterase compounds such as organophosphate and carbamate pesticides. Here we show that tropical reef fish Acanthochromis polyacanthus (or spiny damsel) also exhibits a decrease in ChE activity when exposed to elevated temperature from 28°C to 32°C or 34°C after 4 days. We further demonstrate that the decline persists even after 7 days of recovery at control temperature. This is the first report of a drop in ChE activity in fish as temperature increases. Our results strongly suggest the need for long-term monitoring of water temperature in the field prior to sampling A. polyacanthus for toxicology studies, as temperature is a prolonged and confounding factor for ChE activity in this species. PMID:23891782

Botté, Emmanuelle S; Smith-Keune, Carolyn; Jerry, Dean R

2013-07-04

317

Revertants, low temperature, and correctors reveal the mechanism of F508del-CFTR rescue by VX-809 and suggest multiple agents for full correction.  

PubMed

Cystic fibrosis is mostly caused by the F508del mutation, which impairs CFTR protein from exiting the endoplasmic reticulum due to misfolding. VX-809 is a small molecule that rescues F508del-CFTR localization, which recently went into clinical trial but with unknown mechanism of action (MoA). Herein, we assessed if VX-809 is additive or synergistic with genetic revertants of F508del-CFTR, other correctors, and low temperature to determine its MoA. We explored and integrated those various agents in combined treatments, showing how they add to each other to identify their complementary MoA upon correction of F508del-CFTR. Our experimental and modeling data, while compatible with putative binding of VX-809 to NBD1:ICL4 interface, also indicate scope for further synergistic F508del-CFTR correction by other compounds at distinct conformational sites/cellular checkpoints, thus suggesting requirement of combined therapies to fully rescue F508del-CFTR. PMID:23890012

Farinha, Carlos M; King-Underwood, John; Sousa, Marisa; Correia, Ana Raquel; Henriques, Bárbara J; Roxo-Rosa, Mónica; Da Paula, Ana Carina; Williams, Jonathan; Hirst, Simon; Gomes, Cláudio M; Amaral, Margarida D

2013-07-25

318

Factorize  

NSDL National Science Digital Library

This interactive Java applet helps students explore the relationship between area and multiplication. First, users are asked to input all factor pairs of a given number. Then, selecting each of those factor pairs, the user draws the respective rectangular array by clicking and dragging across a grid. Options include the use of the commutative property (e.g., user must enter both 2x4 and 4x2 for factors of 8 and represent them with different arrays), entering a number of the user's own choice, and an optional scoring feature allowing the user to keep track of the number correct.

2004-01-01

319

In vivo Hepatic Gene Therapy: Complete Albeit Transient Correction of Factor IX Deficiency in Hemophilia B Dogs  

Microsoft Academic Search

Hemophilia B is a bleeding disorder caused by mutations in the factor IX gene. The disorder is X-linked recessive with a prevalence of about 1 in 30,000 Caucasian males. Factor IX is naturally synthesized in the liver and secreted into blood. Here we report the construction of recombinant adenoviral vectors containing the canine factor IX cDNA that are capable of

Mark A. Kay; Charles N. Landen; Steven R. Rothenberg; Lesli A. Taylor; Frances Leland; Sandra Wiehle; Bingliang Fang; Dwight Bellinger; Milton Finegold; Arthur R. Thompson; Marjorie Read; Kenneth M. Brinkhous; Savio L. C. Woo

1994-01-01

320

Numerical expressions for the computation of coincidence-summing correction factors in gamma-ray spectrometry with HPGe detectors.  

PubMed

Numerical expressions to compute gamma-gamma and gamma-X(K) coincidence summing corrections were deduced by using a suitable computer program and a matrix representation of a decay scheme. For point sources only full-energy peak and total efficiencies are needed. Alternatively, values of peak-to-total ratio can be introduced. For extended sources, the same expressions can be considered with the introduction of "effective efficiencies". Examples of the use of the expressions for point sources and a particulate filter sample measured with a 60% relative efficiency HPGe detector are reported. PMID:19892555

Rizzo, S; Tomarchio, E

2009-10-22

321

Motor life: the effects of loading, service factor and temperature rise on insulation life  

Microsoft Academic Search

This paper is intended as a guide on the relative effects of loading, service factor and temperature on the expected insulation life of electric motors. Most refinery, pipeline and chemical plant operators are not motor or insulation designers; neither are the authors. But they do have many discussions with plant operators who want to know the practical answers to questions

B. Campbell; J. Galleno

1998-01-01

322

Molecular Factors and Biochemical Pathways Induced by Febrile Temperature in Intraerythrocytic Plasmodium falciparum Parasites  

Microsoft Academic Search

Intermittent episodes of febrile illness are the most benign and recognized symptom of infection with malaria parasites, although the effects on parasite survival and virulence remain unclear. In this study, we identified the molecular factors altered in response to febrile temperature by measuring differential expression levels of individual genes using high-density oligonucleotide microarray technology and by performing biological assays in

Miranda S. M. Oakley; Sanjai Kumar; Vivek Anantharaman; Hong Zheng; Babita Mahajan; J. David Haynes; J. Kathleen Moch; Rick Fairhurst; Thomas F. McCutchan; L. Aravind

2007-01-01

323

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...

324

Prediction of the Temperature-Dependent Static Form Factor in Hei and He II.  

National Technical Information Service (NTIS)

A method is presented for predicting the temperature-dependent properties of the static form factor in HeI and HeII at low momenta. The prediction is based upon the observation that a single coherent, collective mode of excitation predominates for tempera...

R. D. Etters

1966-01-01

325

FACTORS INFLUENCING YEAR-CLASS STRENGTH OF PERCIDS: A SUMMARY AND A MODEL OF TEMPERATURE EFFECTS  

EPA Science Inventory

Factors regulating year-class strength in the percid genera Stizostedion and Perca are summarized. Some index of water temperature regime correlates significantly with year-class strength of percids in many waterbodies, in several lakes in North America. A probablistic model is p...

326

Blackbody-radiation correction to the polarizability of helium  

SciTech Connect

The correction to the polarizability of helium due to blackbody radiation is calculated near room temperature. A precise theoretical determination of the blackbody radiation correction to the polarizability of helium is essential for dielectric gas thermometry and for the determination of the Boltzmann constant. We find that the correction, for not too high temperature, is roughly proportional to a modified hyperpolarizability (two-color hyperpolarizability), which is different from the ordinary hyperpolarizability of helium. Our explicit calculations provide a definite numerical result for the effect and indicate that the effect of blackbody radiation can be excluded as a limiting factor for dielectric gas thermometry using helium or argon.

Puchalski, M. [Missouri University of Science and Technology, Rolla, Missouri 65409-0640 (United States); Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, PL-60-780 Poznan (Poland); Jentschura, U. D. [Missouri University of Science and Technology, Rolla, Missouri 65409-0640 (United States); Mohr, P. J. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8420 (United States)

2011-04-15

327

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

328

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

329

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

2012-05-31

330

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; Ravi, Dr. Srinivasan [University of Florida, Gainesville

2012-01-01

331

Factors inducing and correction of photometric error introduced to FT-IR spectrometers by a nonlinear detector response  

SciTech Connect

For strongly absorbing bands measured with a Fourier transform infrared (FT-IR) spectrometer, the effects of a nonlinear detector response must be eliminated before Beer{close_quote}s law linearity can be achieved. The effect of the non-linear response of mercury cadmium telluride (MCT) detectors has been evaluated on three commercial FT-IR spectrometers. The greater the photon flux, photon flux density, and the smaller the area of the detector on which the source image is focused, the greater are the effects of the nonlinearity. Detector nonlinearity is manifested by the generation of nonlinear Beer{close_quote}s law plots. A simple correction algorithm has been applied to Beer{close_quote}s law data acquired using both photoconductive MCT and pyroelectric detectors and found to work well. {copyright} {ital 1998 American Institute of Physics.}

Richardson, R.L.; Yang, H.; Griffiths, P.R. [Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343 (United States)

1998-06-01

332

A novel power electronic system for harmonic reduction and power factor correction of single-phase rectifiers  

NASA Astrophysics Data System (ADS)

The objective of this dissertation was to develop a power electronics system that will be used with any existing single-phase rectifier and improve its harmonic content and power factor to an acceptable level. A switching circuit with a boost inductor and two feedback loops, is the result of this work. One of the feedback loops uses a sample of the output voltage of the rectifier to reduce line current harmonics, increase power factor, and to accomplish output voltage regulation. The second feedback loop uses a sample of the line current as the input to further reduce harmonic content in line current and increase power factor. Verification of this circuit in hardware showed that for a load resistance RL of 112 O, the THD has been reduced by 91.45%, power factor has increased by 39.55%, and efficiency has decreased by 8.79%. Also for a load resistance RL of 1005 O, the THD has been reduced by 89.21%, power factor increased by 98.66%, and efficiency decreased by 14.38%. The third harmonic level of the line current is lowered by 93.35% for a load resistance of 112 O, and 82.45% for a load resistance of 1005 O. Thus it can operate for a full range of load resistance. The advantage of this circuit is that it can operate as an add-on circuit to any commercially available rectifier.

Kagalwala, Bela A.

333

Structure of hydrothermal convection in the Upper Rhine Graben as inferred from corrected temperature data and basin-scale numerical models  

NASA Astrophysics Data System (ADS)

Geothermal anomalies in sedimentary basins are strongly controlled by fluid circulation within permeable zones. Exploration of new targets requires the understanding of how and why hydrothermal circulation patterns establish in a particular zone. This study presents a new compilation of newly corrected bottom-hole temperature data in the French part of the Upper Rhine Graben, where the Soultz-sous-Forêts temperature anomaly is locked beneath a local horst structure. After a geostatistically constrained interpolation procedure, maps and cross-sections are extracted from the 3D thermal block, together with the associated standard deviations. Thermal anomalies are preferentially associated with the thickest zones of the permeable fractured Buntsandstein (sandstones) formation, in apparent contradiction with previous models where two major fault zones were suggested to control fluid flow. The underlying fractured granitic basement hosts fluid circulation patterns which are apparently controlled at large-scale by the inclined basement-sediments interface. Based on these observations, numerical models of hydrothermal convection including an inclined basement-sediments interface, a local horst structure, and realistic petrophysical properties have been carried out. The depth-decrease of permeability, the inclination of the interface and the fixed heat flow condition at the base of the model, explain why only a few upwellings can be triggered. Thermal anomalies and a measured temperature profile can be reproduced when fault permeability equals 10- 14 m2. Interestingly, structure of convective patterns also exhibits a second and hotter upwelling, in the Rittershoffen area, 8 km east of the Soultz-sous-Forêts upwelling zone, where another geothermal exploration project is now underway. The understanding of hydrothermal convection with realistic fluid and rock properties clearly appears as a predictive tool for geothermal exploration strategies.

Guillou-Frottier, Laurent; Carr?, Clément; Bourgine, Bernard; Bouchot, Vincent; Genter, Albert

2013-04-01

334

Thermoelectric power factors of nanocarbon ensembles as a function of temperature.  

SciTech Connect

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 B{sub 4}C, 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 {mu}W/K{sup 2} 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.; CNRS-ONERA; Michigan Technological Univ.

2009-01-01

335

Lattice dynamical calculations of anisotropic temperature factors of atoms in quartz, and the structure of ?-quartz  

NASA Astrophysics Data System (ADS)

Temperature factors for oxygen and silicon atoms in ?-quartz were calculated on a Born-von Karman lattice dynamical model of an ordered structure. The calculated thermal ellipsoids were in excellent agreements with those of the previous structure refinements of the order model, for both magnitudes and orientations of the principal axes. The temperature factors are contributed mainly by the soft optic modes in ?-M and the lowest-lying acoustic modes along ?-A, which are also strongly temperature-dependent. The cusp-shaped temperature dependence of mean square displacements, , of oxygen atom, observed previously around the ?- ? transition, are resulted from the softening of these modes. The temperature-dependent modes in ?-A were also found to cause diffuse scattering extending along ±c* of the fourth hexagon of the hk0 reciprocal lattice plane. The negative expansion known in ?-quartz were interpreted in terms of asymmetrical forces exerting on oxygen atoms in Si-O-Si bending modes. In ?-quartz, librational motions of oxygen atoms around Si-Si lines with large amplitudes, whose center is just on the ?-position of high symmetry, must be possible under the condition that bending tetrahedral O-Si-O angles is energetically more favourable than compressing or stretching Si-O bonds.

Kihara, Kuniaki

1993-02-01

336

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

NASA Astrophysics Data System (ADS)

We consider a dilute homogeneous mixture of bosons and spin-polarized fermions at zero temperature. We first construct the formal scheme for carrying out systematic perturbation theory in terms of single particle Green's functions. We especially focus on the description of the boson-fermion interaction. To do so we need to introduce the renormalized boson-fermion T matrix, which we determine to second order in the boson-fermion s-wave scattering length. We also discuss how to incorporate the usual boson-boson T matrix in mean field approximation to obtain the total ground-state properties of the system. The next-order term beyond mean field stems from the boson-fermion interaction and is proportional to aBFkF. The total ground-state energy density to this order is the sum of the kinetic energy of the free fermions, the boson-boson mean-field interaction, the usual mean-field contribution to the boson-fermion interaction energy, and the first boson-fermion correction beyond mean field. We also compute the bosonic and the fermionic chemical potentials, the compressibilities, and the modification to the induced fermion-fermion interaction. We discuss the behavior of the total ground-state energy and the importance of the correction beyond mean field for various parameter regimes, in particular considering mixtures of 6Li and 7Li and of 3He and 4He. Moreover, we determine the modification of the induced fermion-fermion interaction due to the effects beyond mean field. We show that there is no effect on the depletion of the Bose condensate to first order in the boson-fermion scattering length aBF.

Albus, A. P.; Gardiner, S. A.; Illuminati, F.; Wilkens, M.

2002-05-01

337

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

2012-07-27

338

Increase of Efficiency of an AC-DC Power Factor Correction Boost Converter by a Novel Soft-switching Technique  

Microsoft Academic Search

A novel implementation of a high power factor boost converter with increased efficiency is described. In this converter, a new zero-voltage transition technique is used for soft switching of the main and auxiliary switches; also, no additional voltage and current stresses on the main and auxiliary switches occur. The operating modes, theoretical analysis, and design considerations of the proposed converter

M. Mahesh; A. K. Panda

2011-01-01

339

Next-to-leading order corrections for the dipole factorization of deep inelastic scattering structure functions at low x  

NASA Astrophysics Data System (ADS)

The NLO generalization of the dipole factorization formula for the structure functions F2 and FL at low x is calculated using light-front perturbation theory. That result gives some interesting insight into the kinematics of initial state parton showers in mixed-space.

Beuf, Guillaume

2012-02-01

340

??-Corrected Chiral Magnetic Effect  

NASA Astrophysics Data System (ADS)

Using the AdS/CFT correspondence, the effect of ??-correction on the value of Chiral Magnetic Effect (CME) is computed by adding a number of spinning probe D7-branes in the ??-corrected background. We numerically show that the magnitude of CME rises in the presence of ??-correction for massive solutions and this increase is more sensible at higher temperatures. However, this value does not change for massless solution. Although some of the D7-brane embeddings have no CME, after applying the ??-correction they find a non-zero value for the CME. We also show that the effect of ??-correction removes the singularity from some of the D7-brane embeddings.

Ali-Akbari, M.; Taghavi, S. F.

2013-07-01

341

Analysis and Design of a Parallel CUK Power Factor Correction Circuit Based on Power Balance Control Technique  

NASA Astrophysics Data System (ADS)

The analysis and design of a parallel AC to DC CUK converter circuit based on power balance control technique for DC Distributed Power System (DPS) applications are presented. The three parallel modules system with fast dynamic response using single voltage loop control and inductor current calculator for input current wave shaping, inductor current sharing and output voltage regulation, while keeping the power factor very close to unity have been shown. The experimental prototype have been built with a DC output voltage -48V and output power 750W. Each converter operates in Continuous Conducting Mode (CCM) together with hysteresis current control. The experimental results indicate that such scheme is effective and offers the fast transient response. The results obtained are: power factor greater than 0.99 and input current Total Harmonic Distortion (THD) less than 3%. The system offers 85% efficiency and provide good current sharing among the converter modules.

Kamnarn, Uthen; Chunkag, Viboon

342

Harmonics mitigation and power factor correction with a modern three-phase four-leg shunt active power filter  

Microsoft Academic Search

In this paper a compensating system using four-leg shunt active power filter (SAPF) in a three-phase four-wire distribution network which will be able to mitigate harmonics, absorb or generate reactive power, and improve the power factor on supply side, is presented. Two control approaches based on p-q theory and load current detection using phase locked loop (PLL) are proposed. To

Izzeldin Idris Abdalla; K. S. Rama Rao; N. Perumal

2010-01-01

343

Impaired intestinal sugar transport in cirrhotic rats: Correction by low doses of insulin-like growth factor I  

Microsoft Academic Search

BACKGROUND & AIMS: Malnutrition is a complication of liver cirrhosis accompanied by reduced insulin-like growth factor I (IGF-I) availability. The aim of this study was to analyze the effect of IGF-I on intestinal D-galactose absorption in cirrhotic rats.METHODS: IGF-I (2 micrograms.100 g body wt-1.day-1) or saline were given for 14 days to rats in whom cirrhosis was induced with CCl4.

I Castilla-Cortazar; J Prieto; E Urdaneta; M Pascual; M Nunez; E Zudaire; M Garcia; J Quiroga; S Santidrian

1997-01-01

344

Influence of thermochemical factors on the life of the lining of a high temperature reactor  

Microsoft Academic Search

For the purpose of development of measures directed toward increasing the life of the VTR-20, the lining failure mechanism was investigated with the use of microscopic, x-ray diffraction, and analytical chemiacl methods of analysis. It was concluded that the life of the periclase lining of a high-temperature reactor in the production of ferrochrome is determined by a combiantion of factors

V. I. Vasilev; L. A. Dyakonova; I. A. Gnedina; T. L. Rozhdestvenskaya

1986-01-01

345

Influence of thermochemical factors on the life of the lining of a high temperature reactor  

SciTech Connect

For the purpose of development of measures directed toward increasing the life of the VTR-20, the lining failure mechanism was investigated with the use of microscopic, x-ray diffraction, and analytical chemiacl methods of analysis. It was concluded that the life of the periclase lining of a high-temperature reactor in the production of ferrochrome is determined by a combiantion of factors which includes the high process temperatures, intense interaction of the molten material in the lining, impregnation of the refractory primarily by oxides of silicon and calcium, active mass exchange in the occurence of exothermic reactions, temperature variations in the working layer related to the periodic character of service of the reactor, and the presence of joints in the lining. Maintenence on the reactor lining of an ore-slag layer increases the reactor life by 25-50%.

Vasil'ev, V.I.; D'yakonova, L.A.; Gnedina, I.A.; Rozhdestvenskaya, T.L.

1986-07-01

346

Factorization and next-to-leading-order QCD correction in e{sup +}e{sup -}{yields}J/{psi}({psi}(2S))+{chi}{sub c0}  

SciTech Connect

In nonrelativistic QCD, we study e{sup +}e{sup -}{yields}J/{psi}({psi}(2S))+{chi}{sub c0} at B factories, where the P-wave state {chi}{sub c0} is associated with a S-wave state J/{psi} or {psi}(2S). In contrast to the failure of factorization in most cases involving P-wave states, e.g. in B decays, we find that factorization holds in this process at next-to-leading order (NLO) in {alpha}{sub s} and leading order in v, where the associated S-wave state plays a crucial rule in canceling the infrared divergences. We also give some general analyses for factorization in various double charmonium production. The NLO corrections in e{sup +}e{sup -}{yields}J/{psi}({psi}(2S))+{chi}{sub c0} at {radical}(s)=10.6 GeV are found to substantially enhance the cross sections by a factor of about 2.8; hence crucially reducing the large discrepancy between theory and experiment. With m{sub c}=1.5 GeV and {mu}=2m{sub c}, the NLO cross sections are estimated to be 17.9(11.3) fb for e{sup +}e{sup -}{yields}J/{psi}({psi}(2S))+{chi}{sub c0}, which reach the lower bounds of the experiment.

Zhang Yujie; Ma Yanqing [Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Chao Kuangta [Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Center for High Energy Physics, Peking University, Beijing 100871 (China)

2008-09-01

347

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)

1995-06-01

348

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

349

Electron beam quality correction factors for plane-parallel ionization chambers: Monte Carlo calculations using the PENELOPE system.  

PubMed

Simulations of three plane-parallel ionization chambers have been used to determine directly the chamber- and quality-dependent factors fc,Q, instead of the product (Sw,air p)Q, and kQ,Q0 (or kQ,Q,int) for a broad range of electron beam qualities (4-20 MeV) using divergent monoenergetic beams and phase-space data from two accelerators. An original calculation method has been used which circumvents the weakness of the so far assumed independence between stopping-power ratios and perturbation factors. Very detailed descriptions of the geometry and materials of the chambers have been obtained from the manufacturers, and prepared as input to the PENELOPE 2003 Monte Carlo system using a computer code that includes correlated sampling and particle splitting. Values of the beam quality factors have been determined for the case of an electron reference beam. The calculated values have been compared with those in the IAEA TRS-398 dosimetry protocol and the differences analysed. The results for a NACP-02 chamber show remarkably good agreement with TRS-398 at high electron beam qualities but differ slightly at low energies. Arguments to explain the differences include questioning the undemonstrated assumption that the NACP is a 'perturbation-free' chamber even at very low electron beam energies. Results for Wellhöfer PPC-40 and PPC-05 chambers cannot be compared with data from others for these chambers because no calculations or reliable experimental data exist. It has been found that the results for the PPC-40 are very close to those of a Roos chamber, but the values for the PPC-05 are considerably different from those of a Markus chamber, and rather approach those of a Roos chamber. Results for monoenergetic electrons and accelerator phase-space data have been compared to assess the need for detailed and costly simulations, finding very small differences. This questions the emphasis given in recent years to the use of 'realistic' source data for accurate electron beam dosimetry. PMID:15509075

Sempau, Josep; Andreo, Pedro; Aldana, Judith; Mazurier, Jocelyne; Salvat, Francesc

2004-09-21

350

Determining desorption pre-exponential factors from temperature-programmed desorption spectra when the surface is nonuniform  

SciTech Connect

To find desorption pre-exponential factors from temperature-programmed desorption (TPD) spectra, we develop procedures using both the TPD spectra and their derivatives. First, an approximate method is derived using peak temperatures. This method is formally identical with one used for determining pre-exponential factors and desorption activation energies when desorptions are energetically uniform. The method can be used when the pre-exponential factor is constant. We next develop an iterative process that also uses peak temperatures, and again is usable when the pre-exponential factor is constant. This iterative approach should give more exact values of pre-exponential factors than the approximate approach. Using the first derivatives of TPD spectra over the entire range of temperatures leads to a second iterative process. This last procedure allows determination of energy-dependent pre-exponential factors. 8 refs., 13 figs.

Brown, L.F.; Chemburkar, R.M.

1991-03-15

351

Determination of the Effects of Speed, Temperature, and Fuel Factors on Exhaust Emissions  

NASA Astrophysics Data System (ADS)

This study provided a comprehensive approach to examining the relative significance and possible synergistic effects of speed, temperature, and fuel on mobile source emissions modeling. Eleven passenger vehicles from three fuel delivery system control groups were tested, namely, three from carburetor (CARBU), three from throttle body injection (TBI), and five from multi-port fuel injection (MPFI) group. A minimum of 90 tests were conducted on each vehicle with a random combination of three fuel types (Phase 1, Phase 2, and Indolene), three temperatures (50 F, 75 F, and 100 F), and ten speed cycles. Each vehicle was repeated for ten speed cycles (75 F and Indolene). In general, exhaust emissions descended in the order of CARBU, TBI, and MPFI. All vehicles in the CARBU group contained a "dead" catalyst, which probably explained why vehicles in CARBU were "high emitters.". Results from the paired t-test indicated that exhaust emissions difference between Phase 1 and Phase 2 fuels for all vehicles was significant. The net exhaust emissions reduction of Phase 2 over Phase 1 fuel for HC and NOx was 21% and 12%, respectively; which is in good agreements with the CARB projected 17% HC (including evaporative and exhaust emissions) and 11% CO emissions reduction based on 1996 calendar year when Phase 2 fuel is introduced. Temperature had minimal effects on exhaust emissions especially the test cycles were in hot-stabilized mode. Nevertheless, exhaust emissions from cold-start mode were higher than hot-start mode because the catalyst had not reached to optimal operating temperature during the cold-start mode. The relative contributions of speed, temperature, and fuel to exhaust emissions were determined using analysis of variance (ANOVA) and it was found interaction terms among fuel, speed, and temperature were statistically insignificant. Individually, the temperature and fuel factor played a minor role in exhaust emission modeling. Speed and vehicle type were the two dominant factors determining exhaust emissions. These results suggested that more resources should be allocated to cycle related research. Future studies will investigate the second-by-second data including: vehicle speed, engine rpm, exhaust oxygen content, catalyst temperature, HC, CO, NOx, and CO_2 collected from the present study.

Chou, Chia-Yang David

352

Evaluation of AlGaN/GaN Heterostructure Field-Effect Transistors on Si Substrate in Power Factor Correction Circuit  

NASA Astrophysics Data System (ADS)

A new device of high-power AlGaN/GaN heterostructure field-effect transistors (HFETs) fabricated on a Si substrate is proposed. Its application of the power factor correction (PFC) circuit is presented for the first time. The AlGaN/GaN HFETs fabricated on the Si substrate with a gate width of 152 mm exhibited a breakdown voltage of more than 800 V, an on-resistance of 65 m?, and a maximum drain current of more than 50 A. As for the results of the experiment on the PFC at 200 W and f = 109 kHz, a power conversion efficiency of 95.2% was obtained. This value was about 1% higher than that of the PFC-circuit-using Si devices.

Iwakami, Shinichi; Machida, Osamu; Izawa, Yoshimichi; Baba, Ryohei; Yanagihara, Masataka; Ehara, Toshihiro; Kaneko, Nobuo; Goto, Hirokazu; Iwabuchi, Akio

2007-08-01

353

A correction factor to account for mixing in Ghyben-Herzberg and critical pumping rate approximations of seawater intrusion in coastal aquifers  

NASA Astrophysics Data System (ADS)

The classic Ghyben-Herzberg estimate of the depth of the freshwater-saltwater interface together with the Dupuit approximation is a useful tool for developing analytical solutions to many seawater intrusion problems. On the basis of these assumptions, Strack (1976) developed a single-potential theory to calculate critical pumping rates in a coastal pumping scenario. The sharp interface assumption and, in particular, this analytical solution are widely used to study seawater intrusion and the sustainable management of groundwater resources in coastal aquifers. The sharp interface assumption neglects mixing and implicitly assumes that salt water remains static. Consequently, this approximation overestimates the penetration of the saltwater front and underestimates the critical pumping rates that ensure a freshwater supply. We investigate the error introduced by adopting the sharp interface approximation, and we include the effects of dispersion on the formulation of Strack (1976). To this end, we perform numerical three-dimensional variable density flow simulations. We find that Strack's equations can be extended to the case of mixing zone if the density factor is multiplied by an empirically derived dispersion factor [1 - (?T/b')1/6], where ?T is transverse dispersivity and b' is aquifer thickness. We find that this factor can be used not only to estimate the critical pumping rate but also to correct the Ghyben-Herzberg estimate of the interface depth. Its simplicity facilitates the generalization of sharp interface analytical solutions and good predictions of seawater penetration for a broad range of conditions.

Pool, MaríA.; Carrera, Jesús

2011-05-01

354

[Variations of canopy temperature in Quercus variabilis plantation and their relations with micrometeorological factors].  

PubMed

Based on the canopy temperature and micrometeorological data of Quercus variabilis in its main growth season (from May to August) in hilly areas of North China in 2011, this paper analyzed the variations of canopy temperature (T(c)) in Q. variabilis plantation and their relations with micrometeorological factors in typically clear days and cloudy days. From 9:00 to 17:00 in clear days, the boundary layer of canopy was unstable, and the mean T(c) was 3.55 degrees C higher than the mean air temperature (T(a)). In cloudy days, the variations of T(c) were gentler than those in clear days. The T(c) was significantly correlated with T(a), net solar radiation (R(n)), relative humidity, and wind speed, with a multiple correlation coefficient being 0. 825. The T(a) and R(n) were the dominant meteorological factors controlling T(c), and their affecting degree on T(c) was associated with weather condition. PMID:23173447

Wei, Dan-Dan; Zhang, Jin-Song; Meng, Ping; Zheng, Ning; Li, Chun-You; Ren, Ying-Feng

2012-07-01

355

Efficiency correction factors of an ACCUSCAN whole-body counter due to the biodistribution of 134Cs, 137Cs and 60Co.  

PubMed

The efficiency calibration of whole-body counters (WBCs) for monitoring of internal contaminations is usually performed with anthropomorphic physical phantoms assuming homogeneous activity distribution. Besides the inherent limitations of these phantoms in resembling the human anatomy, they do not represent a realistic activity distribution, since in real situations each incorporated radionuclide has its particular biodistribution after entering the systemic circulation. Moreover, the activity content in the different organs and tissues comprising the biokinetics is time dependent. This work aims at assessing the whole-body counting efficiency deviations arising from considering a detailed voxel phantom instead of a standard physical phantom (BOMAB) and at evaluating the effect of the anatomical differences between both phantoms. It also aims at studying the efficiency considering the biodistribution of a set of radionuclides of interest incorporated in the scope of environmental and occupational exposures (inhalation and ingestion) and at computing the time-dependent efficiency correction factors to account for the biodistribution variation over time. For the purpose, Monte Carlo (MC) simulations were performed to simulate the whole-body counting efficiencies and biokinetic models were used to estimate the radionuclides' biokinetic behaviour in the human body after intake. The comparison between the efficiencies obtained with BOMAB and the voxel phantom showed deviations between 1.8 and 11.7 %, proving the adequacy of the BOMAB for WBC calibration. The obtained correction factors show that the effect of the biodistribution in the whole-body counting efficiency is more pronounced in cases of acute activity uptake and long-term retention in certain organs than in cases of homogeneous distribution in body tissues, for which the biokinetics influence can be neglected. This work further proves the powerful combination of MC simulation methods using voxel phantoms and biokinetic models for internal dosimetry studies. PMID:23188813

Bento, J; Barros, S; Teles, P; Vaz, P; Zankl, M

2012-11-27

356

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

357

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

358

Target mass corrections and beyond  

SciTech Connect

I examine the uncertainty of perturbative QCD factorization for (un)polarized hadron structure functions in deep inelastic scattering at a large value of the Bjorken variable xB. The focus will be on Target Mass Corrections and Jet Mass Corrections in the collinear factorization framework.

Accardi, Alberto

2009-01-01

359

Target Mass Corrections and Beyond  

SciTech Connect

I examine the uncertainty of perturbative Quantum Chromodynamics (QCD) factorization for (un)polarized hadron structure functions in deep inelastic scattering at a large value of the Bjorken variable x{sub B} The focus will be on Target Mass Corrections and Jet Mass Corrections in the collinear factorization framework.

Accardi, Alberto [Hampton University, Hampton, VA 23668 (United States) and Jefferson Lab, Newport News, VA 23606 (United States)

2009-08-04

360

Factors controlling cloud microphysics, precipitation rate, and brightness temperature of tropical convective and stratiform clouds  

NASA Astrophysics Data System (ADS)

This paper discusses factors controlling cloud microphysics, precipitation rate and brightness temperature of tropical convective and stratiform clouds. Tropical convective and stratiform clouds are important in radiative forcing of climates and distribution of precipitation over the ocean. The possible effects of climate change on these clouds are still not well understood. Recent studies show that the higher CCN concentration in a convective cloud can lead to more vigorous updrafts and a higher evaporation/precipitation ratio. The stronger updraft often means stronger downdraft and gust fronts, which can trigger convection nearby. This implies that increases in CCN concentration can result in an increase in area coverage and persistence of tropical cirrus and stratiform clouds. The increased cloudiness would then be expected to lower sensible and latent heat flux from the ocean by lowering sea surface temperature, affecting the future development of convective clouds. The sea surface temperature may also change in a local area due to change of ocean circulation in climate change scenarios. Satellite remote sensing is a powerful tool to study tropical and global precipitation distribution. Many physically-based passive-microwave (MW) satellite precipitation algorithms make use of cloud radiation databases (CRDs), which typically consist of microphysical profiles from cloud resolving model (CRMs) and simulated MW brightness temperature (Tb). Thus, it is important to validate Tb simulated by a CRM against the observed Tb. Also, it is important to study how any changes in the tropical clouds due to aerosols and sea surface temperature translate into the precipitation and brightness temperature. The case study chosen is KWAJEX campaign that took place from 23 July to 14 September 1999. Authors have developed microphysical physical framework (Advanced Microphysics Prediction System) to predict ice particle properties explicitly in a CRM (University of Wisconsin-Nonhydrostatic Modeling System) (Hashino and Tripoli, 2007). AMPS also predicts aerosol and liquid spectrum by explicitly resolving sizes. For this study UW-NMS AMPS is set up for 2D simulation with periodic conditions over KWAJEX campaign area with synoptic forcing. The microphysical prediction of AMPS is then validated against in-situ microphysical observations and TRMM TMI measurements. Finally, sensitivity tests to study effects of aerosol properties and sea surface temperature on precipitation rate and Tb are discussed.

Hashino, T.; Casella, D.; Mugnai, A.; Sano, P.; Smith, E. A.; Tripoli, G.

2008-12-01

361

Investigation of potential factors affecting the measurement of dew point temperature in oil-soaked transformers  

NASA Astrophysics Data System (ADS)

Moisture within a transformer's insulation system has been proven to degrade its dielectric strength. When installing a transformer in situ, one method used to calculate the moisture content of the transformer insulation is to measure the dew point temperature of the internal gas volume of the transformer tank. There are two instruments commercially available that are designed for dew point temperature measurement: the Alnor Model 7000 Dewpointer and the Vaisala DRYCAPRTM Hand-Held Dewpoint Meter DM70. Although these instruments perform an identical task, the design technology behind each instrument is vastly different. When the Alnor Dewpointer and Vaisala DM70 instruments are used to measure the dew point of the internal gas volume simultaneously from a pressurized transformer, their differences in dew point measurement have been observed to vary as much as 30 °F. There is minimal scientific research available that focuses on the process of measuring dew point of a gas inside a pressurized transformer, let alone this observed phenomenon. The primary objective of this work was to determine what effect certain factors potentially have on dew point measurements of a transformer's internal gas volume, in hopes of understanding the root cause of this phenomenon. Three factors that were studied include (1) human error, (2) the use of calibrated and out-of-calibration instruments, and (3) the presence of oil vapor gases in the dry air sample, and their subsequent effects on the Q-value of the sampled gas. After completing this portion of testing, none of the selected variables proved to be a direct cause of the observed discrepancies between the two instruments. The secondary objective was to validate the accuracy of each instrument as compared to its respective published range by testing against a known dew point temperature produced by a humidity generator. In a select operating range of -22 °F to -4 °F, both instruments were found to be accurate and within their specified tolerances. This temperature range is frequently encountered in oil-soaked transformers, and demonstrates that both instruments can measure accurately over a limited, yet common, range despite their different design methodologies. It is clear that there is another unknown factor present in oil-soaked transformers that is causing the observed discrepancy between these instruments. Future work will include testing on newly manufactured or rewound transformers in order to investigate other variables that could be causing this discrepancy.

Kraus, Adam H.

362

Two types of phantom scatter correction factors for high-energy photons  

NASA Astrophysics Data System (ADS)

Two types of phantom scatter correction factors are introduced for high-energy photons. One is the traditional correction factor. It is produced using the primary absorbed dose under lateral CPE (charged particle equilibrium). It usually takes a non-zero value at zero-area field. The other is produced using the actual primary absorbed dose, which fails in lateral CPE when the field is small. It takes a value of zero at zero-area field. The two types of correction factors can be connected with the laterally spread primary absorbed dose (LSD).

Iwasaki, Akira

1996-12-01

363

Molecular Factors and Biochemical Pathways Induced by Febrile Temperature in Intraerythrocytic Plasmodium falciparum Parasites? †  

PubMed Central

Intermittent episodes of febrile illness are the most benign and recognized symptom of infection with malaria parasites, although the effects on parasite survival and virulence remain unclear. In this study, we identified the molecular factors altered in response to febrile temperature by measuring differential expression levels of individual genes using high-density oligonucleotide microarray technology and by performing biological assays in asexual-stage Plasmodium falciparum parasite cultures incubated at 37°C and 41°C (an elevated temperature that is equivalent to malaria-induced febrile illness in the host). Elevated temperature had a profound influence on expression of individual genes; 336 of approximately 5,300 genes (6.3% of the genome) had altered expression profiles. Of these, 163 genes (49%) were upregulated by twofold or greater, and 173 genes (51%) were downregulated by twofold or greater. In-depth sensitive sequence profile analysis revealed that febrile temperature-induced responses caused significant alterations in the major parasite biologic networks and pathways and that these changes are well coordinated and intricately linked. One of the most notable transcriptional changes occurs in genes encoding proteins containing the predicted Pexel motifs that are exported into the host cytoplasm or inserted into the host cell membrane and are likely to be associated with erythrocyte remodeling and parasite sequestration functions. Using our sensitive computational analysis, we were also able to assign biochemical or biologic functional predictions for at least 100 distinct genes previously annotated as “hypothetical.” We find that cultivation of P. falciparum parasites at 41°C leads to parasite death in a time-dependent manner. The presence of the “crisis forms” and the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling-positive parasites following heat treatment strongly support the notion that an apoptosis-like cell death mechanism might be induced in response to febrile temperatures. These studies enhance the possibility of designing vaccines and drugs on the basis of disruption in molecules and pathways of parasite survival and virulence activated in response to febrile temperatures.

Oakley, Miranda S. M.; Kumar, Sanjai; Anantharaman, Vivek; Zheng, Hong; Mahajan, Babita; Haynes, J. David; Moch, J. Kathleen; Fairhurst, Rick; McCutchan, Thomas F.; Aravind, L.

2007-01-01

364

Influence of some factors on the damping property of fiber-reinforced epoxy composites at low temperature  

Microsoft Academic Search

Fiber-reinforced composites are applied widely as supporting and connecting structures in cryogenic engineering because of their high strength and low thermal conductivity. In these applications, materials are often under cyclic loading. Knowledge of damping behavior at low temperature is of importance. In this paper, the influence of some factors on the damping property of fiber-reinforced composites at low temperature is

P. Q. Zhang; J. H. Ruan; W. Z. Li

2001-01-01

365

Temperature and Leaf Osmotic Potential as Factors in the Acclimation of Photosynthesis to High Temperature in Desert Plants 1  

PubMed Central

Seasonal changes in the high temperature limit for photosynthesis of desert winter annuals growing under natural conditions in Death Valley, California were studied using an assay based upon chlorophyll fluorescence. All species of this group were 6 to 9°C more tolerant of high temperature at the end of the growing season (May) than at its beginning (February). Over this same time period, the mean daily maximum air temperatures increased by 12°C. Laboratory studies have demonstrated that increases in thermal tolerance could be induced by increasing growth temperature alone. For plants growing under field conditions there was also a good correlation between the thermal tolerance of leaves and the osmotic potential of leaf water, indicating that increases in the concentrations of some small molecules might also confer increased thermal tolerance. Isolated chloroplast thylakoids subjected to increasing concentrations of sorbitol could be demonstrated to have increased thermal tolerance.

Seemann, Jeffrey R.; Downton, W. John S.; Berry, Joseph A.

1986-01-01

366

Fluctuation corrections to thermodynamic functions: Finite-size effects  

NASA Astrophysics Data System (ADS)

The explicit thermodynamic functions, in particular, the specific heat of a spin system interacting with a spin bath which exerts finite dissipation on the system are determined. We show that the specific heat is a sum of the products of a thermal equilibration factor that carries the temperature dependence and a dynamical correction factor, characteristic of the dissipative energy flow under steady state from the system. The variation of specific heat with temperature is accompanied by an abrupt transition that depends on these dynamical factors characteristic of the finite system size.

Sinha, Sudarson Sekhar; Ghosh, Arnab; Ray, Deb Shankar

2013-04-01

367

High Temperature Requirement Factor A1 (HTRA1) Gene Regulates Angiogenesis through Transforming Growth Factor-? Family Member Growth Differentiation Factor 6*  

PubMed Central

Genome-wide association study (GWAS) has identified genetic variants in the promoter region of the high temperature requirement factor A1 (HTRA1) gene associated with age-related macular degeneration (AMD). As a secreted serine protease, HTRA1 has been reported to interact with members of the transforming growth factor-? (TGF-?) family and regulate their signaling pathways. Growth differentiation factor 6 (GDF6), a member of the TGF-? family, is involved in ectoderm patterning and eye development. Mutations in GDF6 have been associated with abnormal eye development that may result in microphthalmia and anophthalmia. In this report, we identified a single nucleotide polymorphism (SNP) rs6982567 A/G near the GDF6 gene that is significantly associated with AMD (p value = 3.54 × 10?8). We demonstrated that the GDF6 AMD risk allele (rs6982567 A) is associated with decreased expression of the GDF6 and increased expression of HTRA1. Similarly, the HTRA1 AMD risk allele (rs10490924 T) is associated with decreased GDF6 and increased HTRA1 expression. We observed decreased vascular development in the retina and significant up-regulation of GDF6 gene in the RPE layer, retinal and brain tissues in HTRA1 knock-out (htra1?/?) mice as compared with the wild-type counterparts. Furthermore, we showed enhanced SMAD signaling in htra1?/? mice. Our data suggests a critical role of HTRA1 in the regulation of angiogenesis via TGF-? signaling and identified GDF6 as a novel disease gene for AMD.

Zhang, Li; Lim, Siok Lam; Du, Hongjun; Zhang, Ming; Kozak, Igor; Hannum, Gregory; Wang, Xiaolei; Ouyang, Hong; Hughes, Guy; Zhao, Ling; Zhu, Xuemei; Lee, Clara; Su, Zhiguang; Zhou, Xinrong; Shaw, Robert; Geum, Dongho; Wei, Xinran; Zhu, Jin; Ideker, Trey; Oka, Chio; Wang, Ningli; Yang, Zhenglin; Shaw, Peter X.; Zhang, Kang

2012-01-01

368

Low temperature resistivity, thermoelectricity, and power factor of Nb doped anatase TiO2  

NASA Astrophysics Data System (ADS)

The resistivity of a very high quality anatase TiO2 doped with 6% of Nb was measured from 300 K down to 40 mK. No sign of superconductivity was detected. Instead, a minute quantity of cation vacancies resulted in a Kondo scattering. Measurements of thermo-electric power and resistivity were extended up to 600 K. The calculated power factor has a peak value of 14 ?W/(K2cm) at 350 K, which is comparable to that of Bi2Te3 [Venkatasubramanian et al., Nature 413, 597 (2001)], the archetype thermolectrics. Taking the literature value for the thermal conductivity of Nb doped TiO2 thin films, the calculated figure of merit (ZT) is in the range of 0.1 above 300 K. This value is encouraging for further engineering of the material in order to reach ZT of 1 suitable for high temperature thermoelectrics.

Ja?imovi?, J.; Gaál, R.; Magrez, A.; Piatek, J.; Forró, L.; Nakao, S.; Hirose, Y.; Hasegawa, T.

2013-01-01

369

Temperature-dependent lateral and transverse distribution of the epidermal growth factor receptor in A431 plasma membranes  

Microsoft Academic Search

Summary To elucidate further the structure and molecular dynamics of the epidermal growth factor receptor, temperature-dependent aggregation and extracellular protrusion of the epidermal growth factor receptor in isolated plasma membranes from A431 cells were examined by fluorescence energy-transfer techniques. Epidermal growth factor was labeled at the amino terminus with either fluorescein isothiocyanate or tetramethylrhodamine isothiocyanate. A radionuclide receptor displacement assay

John R. Azevedo; David A. Johnson

1990-01-01

370

The link between metabolic rate and body temperature in galliform birds in thermoneutral and heat exposure conditions: The classical and phylogenetically corrected approach  

Microsoft Academic Search

Three galliform species (grey partridges, ring-necked pheasants, and king quail) were involved in body temperature and resting metabolic rate measurements over a broad range of ambient temperatures (20–45°C). At thermoneutrality, inter-species differences in colonic temperature, as well as in metabolic rate, were observed. During heat exposure, all species reacted by elevating their body temperatures above 44°C, thereby inducing temporary hyperthermia.

Tomasz Pis

2010-01-01

371

Temperature  

NSDL National Science Digital Library

This article discusses the relationship between temperature and heat and kinetic energy and it shows how to convert from degrees Fahrenheit to Centigrade. It also includes links to other resources, data, maps, and classroom activities.

2008-04-08

372

Chromatographic background drift correction coupled with parallel factor analysis to resolve coelution problems in three-dimensional chromatographic data: quantification of eleven antibiotics in tap water samples by high-performance liquid chromatography coupled with a diode array detector.  

PubMed

Chromatographic background drift correction has been an important field of research in chromatographic analysis. In the present work, orthogonal spectral space projection for background drift correction of three-dimensional chromatographic data was described in detail and combined with parallel factor analysis (PARAFAC) to resolve overlapped chromatographic peaks and obtain the second-order advantage. This strategy was verified by simulated chromatographic data and afforded significant improvement in quantitative results. Finally, this strategy was successfully utilized to quantify eleven antibiotics in tap water samples. Compared with the traditional methodology of introducing excessive factors for the PARAFAC model to eliminate the effect of background drift, clear improvement in the quantitative performance of PARAFAC was observed after background drift correction by orthogonal spectral space projection. PMID:23827465

Yu, Yong-Jie; Wu, Hai-Long; Fu, Hai-Yan; Zhao, Juan; Li, Yuan-Na; Li, Shu-Fang; Kang, Chao; Yu, Ru-Qin

2013-06-14

373

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-...

374

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

375

Multispectral imaging of the olfactory bulb activation: influence of realistic differential pathlength correction factors on the derivation of oxygenation and total hemoglobin concentration maps  

NASA Astrophysics Data System (ADS)

In vivo multispectral reflectance imaging has been extensively used in the somatosensory cortex (SsC) in anesthetized rodents to collect intrinsic signal during activation and derive hemodynamics signals time courses. So far it has never been applied to the Olfactory Bulb (OB), although this structure is particularly well suited to the optical study of brain activation due to the its well defined organization, the ability to physiologically activate it with odorants, and the low depth of the activated layers. To obtain hemodynamics parameters from reflectance variations data, it is necessary to take into account a corrective factor called Differential Pathlength (DP). It is routinely estimated using Monte Carlo simulations, modeling photons propagation in simplified infinite geometry tissue models. The first goal of our study was to evaluate the influence of more realistic layered geometries and optical properties on the calculation of DP and ultimately on the estimation of the hemodynamics parameters. Since many valuable results have been obtained previously by others in the SSc, for the purpose of validation and comparison we performed Monte Carlo simulations in both the SSC and the OB. We verified the assumption of constant DP during activation by varying the hemoglobin oxygen saturation, total hemoglobin concentration and we also studied the effect of a superficial bone layer on DP estimation for OB. The simulations show the importance of defining a finite multilayer model instead of the coarse infinite monolayer model, especially for the SSc, and demonstrate the need to perform DP calculation for each structure taking into account their anatomofunctional properties. The second goal of the study was to validate in vivo multispectral imaging for the study of hemodynamics in the OB during activation. First results are presented and discussed.

Renaud, R.; Gurden, H.; Chery, R.; Bendhamane, M.; Martin, C.; Pain, F.

2011-02-01

376

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

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

1993-01-01

377

Body temperature modulates the effect of platelet-activating factor (PAF) on airways responsiveness in the rabbit  

Microsoft Academic Search

Platelet-activating factor (PAF) is a potent mediator known to cause bronchoconstriction and increase airways responsiveness.In vitro studies have shown that the effects of PAF on cell function can be very temperature-dependent. The aim of the current study was to investigate the effect of elevated body temperature on numbers of circulating cells and pulmonary function in anesthetized rabbits in response to

M. M. Nieminen; M. Hill; C. G. Irvin

1991-01-01

378

Factors controlling corrosion in high-temperature aqueous solutions: a contribution to the dissociation and solubility data influencing corrosion processes  

Microsoft Academic Search

Typical materials for applications in high-temperature, high-pressure aqueous solutions are stainless steels, nickel-base alloys, titanium, tantalum, noble metals, or ceramics. Under these conditions, these materials are often severely attacked, especially in the presence of acids, salts, or gases.Corrosion phenomena in high-temperature aqueous solutions are mainly influenced by the following factors: dissociation of acids, salts, and bases, the solubility of gases,

P. Kritzer; N. Boukis; E. Dinjus

1999-01-01

379

Temperature regulates hypoxia-inducible factor-1 (HIF-1) in a poikilothermic vertebrate, crucian carp (Carassius carassius)  

Microsoft Academic Search

Hypoxia-inducible transcription factor-1 (HIF-1) is a master regulator of hypoxia-induced gene responses. To find out whether HIF-1 function is involved in gene expression changes associated with temperature acclimation as well as in hypoxia adaptation in poikilotherms, we studied HIF-1 DNA binding activity and HIF-1 expression in normoxia and during hypoxia (0.7·mg·l -1 ·O2) in crucian carp at temperatures of 26,

Eeva Rissanen; Hanna K. Tranberg; Jørund Sollid; Göran E. Nilsson; Mikko Nikinmaa

2006-01-01

380

Incubation Temperature Affects Plasma Insulin-Like Growth Factors in Embryos from Selected Lines of Turkeys1  

Microsoft Academic Search

An experiment was conducted to test the hypothesis that incubator temperature may affect circu- lating insulin-like growth factors (IGF-I and IGF-II). In prior studies, growth of turkey embryos was altered by increasing incubator temperatures. Interestingly, the em- bryonic growth of a growth-selected line (F) was reduced, whereas embryos from an egg-production-selected line (E) did not alter embryonic growth but altered

V. L. Christensen; J. P. McMurtry; W. E. Donaldson; K. E. Nestor

381

Elevated Temperature after Hypoxic-Ischemic Encephalopathy: A Risk Factor for Adverse Outcome  

PubMed Central

Objective To determine if the risk of death or moderate/severe disability in term infants with hypoxic-ischemic encephalopathy increases with relatively high esophageal or skin temperature occurring between 6 and 78 hours following birth. Patients and Methods This is an observational secondary study within the NICHD Neonatal Research Network randomized trial comparing whole body cooling and usual care (control) for term infants with hypoxic-ischemic encephalopathy. Esophageal and skin temperatures were recorded serially for 72 hours. Each infant’s temperatures for each site were rank ordered. The high temperature was defined for each infant as the mean of all temperature measurements in the upper quartile. The low temperature was similarly defined as the mean of the lower quartile. Outcome was related to temperature in three logistic regressions for the high, median and low temperature at each temperature site for each group adjusting for level of encephalopathy, gender, gestational age and race. Results In control infants the mean esophageal temperature was 37.2±0.7°C over the 72 hours and 63, 22 and 8% of all temperatures were > 37, > 37.5 and > 38°C, respectively. For skin temperature the mean was 36.5±0.8°C and 12, 5 and 2% of all temperatures were > 37, > 37.5 and > 38°C, respectively. The odds of death or disability were increased 3.6–4 fold for each centigrade increase in the highest quartile of skin or esophageal temperature. There were no associations between temperature and outcome in the cooled group. Conclusion Relatively high temperatures during usual care following hypoxia-ischemia were associated with increased risk of adverse outcome. The results may reflect underlying brain injury and/or adverse effects of temperature on outcome.

Laptook, Abbot; Tyson, Jon; Shankaran, Seetha; McDonald, Scott; Ehrenkranz, Richard; Fanaroff, Avroy; Donovan, Edward; Goldberg, Ronald; O'Shea, T. Michael; Higgins, Rosemary D.; Poole, W. Kenneth

2009-01-01

382

Detergents and water temperature as factors in methyl parathion removal from denim fabrics  

Microsoft Academic Search

Conclusions Based on the results of this investigation, contaminated denim fabrics should not be laundered in 30°C (85°F) temperature; hotter temperatures are more effective. Although detergents could not be statistically separated, heavy duty liquid detergents appeared to excel in providing higher levels of pesticide removal in water temperatures of 49°C and 60°C. To determine the optimal conditions for pesticide removal

C. B. Easley; J. M. Laughlin; R. E. Gold; K. Schmidt

1982-01-01

383

Managing the supercell approximation for charged defects in semiconductors: Finite-size scaling, charge correction factors, the band-gap problem, and the ab initio dielectric constant  

NASA Astrophysics Data System (ADS)

The errors arising in ab initio density functional theory studies of semiconductor point defects using the supercell approximation are analyzed. It is demonstrated that (a) the leading finite size errors are inverse linear and inverse cubic in the supercell size and (b) finite size scaling over a series of supercells gives reliable isolated charged defect formation energies to around ±0.05eV . The scaled results are used to test three correction methods. The Makov-Payne method is insufficient, but combined with the scaling parameters yields an ab initio dielectric constant of 11.6±4.1 for InP. ? point corrections for defect level dispersion are completely incorrect, even for shallow levels, but realigning the total potential in real-space between defect and bulk cells actually corrects the electrostatic defect-defect interaction errors as well. Isolated defect energies to ±0.1eV are then obtained using a 64 atom supercell, though this does not improve for larger cells. Finally, finite size scaling of known dopant levels shows how to treat the band gap problem: in ?200 atom supercells with no corrections, continuing to consider levels into the theoretical conduction band (extended gap) comes closest to experiment. However, for larger cells or when supercell approximation errors are removed, a scissors scheme stretching the theoretical band gap onto the experimental one is in fact correct.

Castleton, C. W. M.; Höglund, A.; Mirbt, S.

2006-01-01

384

The cerium magnetic form factor and diffuse polarization in CeRh3B2 as functions of temperature  

NASA Astrophysics Data System (ADS)

In the compound CeRh3B2, a rather special polarization of the conduction electrons along the c-chains of cerium atoms had been previously reported at low temperatures (Alonso et al 1998 J. Magn. Magn. Mater. 177-181 1048). The distribution of the CeRh3B2 magnetization has now been studied as a function of temperature up to 150 K—that is, above the Curie temperature of 115 K. The magnetization density maps have been obtained from polarized neutron diffraction experiments by using the maximum entropy method. The cerium form factor has also been analysed. Calculations of the form factor including several multiplets are developed and it is shown that it is necessary to take into account the influence of the higher multiplet of the Ce3+ ion. This result is coherent with the observation of a peak at high energy in the inelastic neutron spectra, indicating a very large crystal electric field splitting. Both analyses lead to the same conclusion that, on heating, the diffuse negative magnetization observed at low temperature along the cerium chains disappears at the magnetic ordering temperature. The influence of the second multiplet of the Ce3+ ion could be part of the explanation for the low value of the 4f moment and the large Curie temperature in CeRh3B2.

Givord, F.; Boucherle, J.-X.; Lelièvre-Berna, E.; Lejay, P.

2004-03-01

385

Regulation of temperature-responsive flowering by MADS-box transcription factor repressors.  

PubMed

Changes in ambient temperature affect flowering time in plants; understanding this phenomenon will be crucial for buffering agricultural systems from the effects of climate change. Here, we show that levels of FLM-?, an alternatively spliced form of the flowering repressor FLOWERING LOCUS M, increase at lower temperatures, repressing flowering. FLM-? interacts with SHORT VEGETATIVE PHASE (SVP); SVP is degraded at high temperatures, reducing the abundance of the SVP-FLM-? repressor complex and, thus, allowing the plant to flower. The svp and flm mutants show temperature-insensitive flowering in different temperature ranges. Control of SVP-FLM-? repressor complex abundance via transcriptional and splicing regulation of FLM and posttranslational regulation of SVP protein stability provides an efficient, rapid mechanism for plants to respond to ambient temperature changes. PMID:24030492

Lee, Jeong Hwan; Ryu, Hak-Seung; Chung, Kyung Sook; Posé, David; Kim, Soonkap; Schmid, Markus; Ahn, Ji Hoon

2013-09-12

386

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

387

Factors influencing low-temperature photo-assisted OMVPE growth of ZnSe  

Microsoft Academic Search

The influence of temperature and ultraviolet (UV) light intensity on the optical characteristics of low-temperature, photo-assisted OMVPE growth of ZnSe on GaAs substrates has been studied. The epitaxial ZnSe was grown using the sources DMSe, DMZn and DMCd, with growth temperature varied from 360 to 400°C. We found that the UV intensity strongly influenced the optical quality of the epitaxial

M. R. Gokhale; K. X. Bao; P. D. Healey; F. C. Jain; J. E. Ayers

1996-01-01

388

Factors influencing stream temperatures in small streams: substrate effects and a shading experiment  

Microsoft Academic Search

The temperature of stream water is an important control of many in-stream processes. To better understand the processes and consequences of solar energy inputs to streams, stream temperature dynamics were examined before, during, and after experimental shading of a 150-m reach of a second-order stream in the Oregon Cascade Range. Maxi- mum water temperatures declined significantly in the shaded reach,

Sherri L. Johnson

2004-01-01

389

Correcting Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) High Altitude (40 - 65 km) Temperature Retrievals for Instrumental Correlated Noise and Biases  

NASA Astrophysics Data System (ADS)

Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) nadir-soundings have been used to derive atmospheric temperatures up to roughly 40 km [Conrath et al., JGR 105 2000, Smith et al., JGR 106, 2001], and MGS-TES limb soundings have been used to extend the atmospheric temperature data set to > 60 km in altitude [Smith et al., JGR 106, 2001]. The ~40 - ~65 km altitude range probed by the MGS-TES limb sounding is particularly important for capturing key dynamical features such as the warm winter polar mesosphere [e.g., Smith et al., JGR 106, 2001; McCleese et al., Nature Geoscience 1, 2008], and the response of thermal tides to dust opacity [e.g. Wilson and Hamilton, J. Atmos. Sci. 53, 1996]. Thus accurate and precise temperature profiles at these altitudes are particularly important for constraining global circulation models. They are also critical for interpreting observations of mesospheric condensate aerosols [e.g., Määttänen et al., Icarus 209, 2010; McConnochie et al., Icarus 210, 2010)]. We have indentified correlated noise components in the MGS-TES limb sounding radiances that propagate into very large uncertainties in the retrieved temperatures. We have also identified a slowly varying radiance bias in the limb sounding radiances. Note that the nadir-sounding-based MGS-TES atmospheric temperatures currently available from the Planetary Data System are not affected by either of these issues. These two issues affect the existing MGS-TES limb sounding temperature data set are as follows: Considering, for example, the 1.5 Pascal pressure level (which typically falls between 50 and 60 km altitude), correlated-noise induced standard errors for individual limb-sounding temperature retrievals were 3 - 5 K in Mars Year 24, rising to 5 - 15 K in Mars Year 25 and 10 - 15 K in Mars Year 26 and 27. The radiance bias, although consistent on ~10-sol time scales, is highly variable over the course of the MGS-TES mission. It results in temperatures (at the 1.5 Pascal level) biased low by as much as 7 K in some periods and biased high by as much as 4 K in other periods, although typical temperature biases are less than 2 K in magnitude and the average bias over the course of the mission is near zero. We have developed techniques that essentially eliminate the variable radiance bias and the correlated noise problems, resulting in a dramatically more precise and accurate high altitude temperature data set. We expect, for example, to reduce temperature uncertainties at the 1.5 Pascal level to ~1 - ~2 K. The radiance bias is addressed simply by subtracting a running average space-pointed spectra. The correlated-noise is addressed by identifying the background noise covariance matrix from the space-pointed spectra, and then performing the retrievals in a basis that diagonalizes this matrix. We will present comparisons of this improved data set with the previous version, and with the Mars Climate Sounder data set [e.g., Kleinböhl et al., JGR 114, 2009].

McConnochie, T. H.; Smith, M. D.

2011-12-01

390

Field Correction for Component Pack packaged with ...  

Center for Biologics Evaluation and Research (CBER)

... Field Correction for Component Pack packaged with Mononine (Coagulation Factor IX, Human)-CSL Behring. DATE NOTIFICATION INITIATED: ... More results from www.fda.gov/biologicsbloodvaccines/safetyavailability/recalls

391

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

2012-08-23

392

Individual pebble temperature peaking factor due to local pebble arrangement in a pebble bed reactor core  

Microsoft Academic Search

Scientists at the German AVR pebble bed nuclear reactor discovered that the surface temperature of some of the pebbles in the AVR core were at least 200K higher than previously predicted by reactor core analysis calculations. The goal of this research paper is to determine whether a similar unexpected fuel temperature increase of 200K can be attributed solely or mostly

Vladimir Sobes; Benoit Forget; Andrew Kadak

2011-01-01

393

Temperature readjustment factors for application to MIL-HDBK-217C failure rates  

Microsoft Academic Search

Base failure rates for transistors and diodes are listed in MIL-HDBK-217C, 'Reliability Prediction of Electronic Equipment', on the basis of ambient temperatures, regardless of the cooling technique used. This basis is reasonable if the cooling method is free convection to ambient air and radiation to the surroundings. However, if other methods are used for cooling electronic parts, the temperature adjustment

L. A. Strattan; G. N. Morrison

1982-01-01

394

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...

395

The tumor suppressor gene p53 can mediate transforming growth [corrected] factor beta1-induced differentiation of leukemic cells independently of activation of the retinoblastoma protein.  

PubMed

Although the involvement of the tumor suppressor gene p53 in normal hematopoiesis is uncertain, it can give rise to differentiation signals in leukemic cells. It is not clear, however, whether differentiation merely is a consequence of the ability of p53 to arrest cell proliferation or whether hitherto unknown molecular mechanisms are responsible for the p53-mediated differentiation. To further explore the role of p53 in leukemic cell differentiation, we investigated whether transforming growth factor beta1 (TGF-beta1), a cytokine involved in cell cycle control at several levels, can cooperate with wild-type p53 to induce differentiation of monoblastic U-937 and erythroleukemic K562 cells. Indeed, wild-type p53-expressing cells were found to be more sensitive to TGF-beta1-induced differentiation than control cells, lending support to the idea that p53 is of importance for differentiation induction of leukemic cells. In addition, it is shown that TGF-beta1 can suppress p53-mediated cell death, thus reinforcing the differentiation response. The cyclin-dependent kinase inhibitor p21 and the retinoblastoma protein (pRb) are downstream effectors of p53-mediated growth arrest. Therefore, the roles for these molecules in p53-mediated differentiation were examined. The p53-dependent signals of differentiation were associated with induction of p21 in both cell lines investigated. However, activation of pRb by induced hypophosphorylation and concomitant decreased growth rate on p53-mediated differentiation was observed only in U-937 cells expressing an inducible, temperature-sensitive form of p53 but not in K562 cells constitutively expressing p53. Thus, our data suggest a role for p53 in the regulation of differentiation in leukemic cells that can be independent of its ability to activate pRb and arrest cell proliferation. PMID:9342191

Ehinger, M; Bergh, G; Johnsson, E; Gullberg, U; Olsson, I

1997-10-01

396

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

PubMed

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). PMID:22080753

Laakso, Ilkka; Hirata, Akimasa

2011-11-11

397

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

398

Temperature effect correction for the cosmic ray muon data observed at the Brazilian Southern Space Observatory in São Martinho da Serra  

NASA Astrophysics Data System (ADS)

The negative atmospheric temperature effect observed in the muon intensity measured by surface-level detectors is related to the atmospheric expansion during summer periods. According the first explanation given, the path of muons from the higher atmospheric level (where they are generated) to the ground becomes longer, and more muons decay, leading to a muon intensity decrease. A significant negative correlation, therefore, is expected between the altitude of the equi-pressure surface and the muon intensity. We compared measurements of the altitude of 100 hPa equi-pressure surface and data from the multidirectional muon detector installed at the Brazilian Southern Space Observatory in São Martinho da Serra, RS. Significant correlation coefficient were found (up to 0.95) when using data observed in 2008. For comparison, data from the multidirectional muon detector of Nagoya, located in the opposite hemisphere, is studied and an anti-phase in the cosmic ray variation related with the temperature effect is expected between data from detectors of Nagoya and São Martinho da Serra. The temperature influence is higher for the directional channels of Nagoya than for ones of São Martinho da Serra.

Braga, C. R.; Dal Lago, A.; Kuwabara, T.; Schuch, N. J.; Munakata, K.

2013-02-01

399

Effect of Temperature Stratification Near Heating Elements on the Measured Energy Factors of Electric Water Heaters.  

National Technical Information Service (NTIS)

Two different models of 190 L (50 gallon) residential electric water heaters were tested to investigate problems that arise in determining their energy efficiencies due to the steep temperature gradient near the lower heating element. This gradient makes ...

W. M. Healy

2008-01-01

400

Structure factor of acoustic emission upon high-temperature deformation of aluminum  

Microsoft Academic Search

The accumulation of deformation and acoustic emission upon high-temperature loading of aluminum has been studied. It has been\\u000a established that in aluminum the accumulation of deformation in the course of a thermomechanical cycle brings about the formation\\u000a of deformation bands whose density is of a pronounced quasi-periodic character depending on the temperature. The minimum and\\u000a the maximum of the density

V. A. Plotnikov; S. V. Makarov

2008-01-01

401

Q factor of megahertz LC circuits based on thin films of YBaCuO high-temperature superconductor  

NASA Astrophysics Data System (ADS)

High-frequency properties of resonant structures based on thin films of YBa2Cu3O7 ? high-temperature superconductor are studied experimentally in the frequency range 30 100 MHz. The structures planar induction coils with a self-capacitance fabricated on neodymium gallate and lanthanum aluminate substrates. The unloaded Q factor of the circuits exceeds 2 × 105 at 77 K and 40 MHz. Possible loss mechanisms that determine the Q factor of the superconducting resonant structures in the megahertz range are considered.

Masterov, D. V.; Pavlov, S. A.; Parafin, A. E.

2008-05-01

402

Q factor of megahertz LC circuits based on thin films of YBaCuO high-temperature superconductor  

Microsoft Academic Search

High-frequency properties of resonant structures based on thin films of YBa2Cu3O7–? high-temperature superconductor are studied experimentally in the frequency range 30–100 MHz. The structures planar induction\\u000a coils with a self-capacitance fabricated on neodymium gallate and lanthanum aluminate substrates. The unloaded Q factor of\\u000a the circuits exceeds 2 × 105 at 77 K and 40 MHz. Possible loss mechanisms that determine

D. V. Masterov; S. A. Pavlov; A. E. Parafin

2008-01-01

403

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

404

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

405

Temperature-Dependent Production of Various PlcR-Controlled Virulence Factors in Bacillus weihenstephanensis Strain KBAB4  

PubMed Central

The Bacillus cereus sensu lato complex has recently been divided into several phylogenetic groups with clear differences in growth temperature range. However, only a few studies have investigated the actual pathogenic potential of the psychrotolerant strains of the B. cereus group at low temperature, and little information is available concerning gene expression at low temperature. We found that vegetative cells of the psychrotolerant B. weihenstephanensis strain KBAB4 were pathogenic against the model insect Galleria mellonella at 15°C but not at 30°C. A similar temperature-dependent difference also was observed for the supernatant, which was cytotoxic to Vero epithelial cell lines and to murine macrophage J774 cells at 15°C but not at 30°C. We therefore determined the effect of low temperature on the production of various proteins putatively involved in virulence using two-dimensional protein gel electrophoresis, and we showed that the production of the Hbl enterotoxin and of two proteases, NprB and NprP2, was greater at a growth temperature of 15°C than at 30°C. The quantification of the mRNA levels for these virulence genes by real-time quantitative PCR at both temperatures showed that there was also more mRNA present at 15°C than at 30°C. We also found that at 15°C, hbl mRNA levels were maximal in the mid- to late exponential growth phase. In conclusion, we found that the higher virulence of the B. cereus KBAB4 strain at low temperature was accompanied by higher levels of the production of various known PlcR-controlled virulence factors and by a higher transcriptional activity of the corresponding genes.

Rejasse, A.; Gilois, N.; Barbosa, I.; Huillet, E.; Bevilacqua, C.; Tran, S.; Ramarao, N.; Stenfors Arnesen, L. P.

2012-01-01

406

Structure factor of acoustic emission upon high-temperature deformation of aluminum  

NASA Astrophysics Data System (ADS)

The accumulation of deformation and acoustic emission upon high-temperature loading of aluminum has been studied. It has been established that in aluminum the accumulation of deformation in the course of a thermomechanical cycle brings about the formation of deformation bands whose density is of a pronounced quasi-periodic character depending on the temperature. The minimum and the maximum of the density of deformation bands correspond to the temperature of jumplike development of deformation and to the monotonic character of deformation accumulation, respectively. The monotonic accumulation of deformation is accompanied by a monotonic growth of the root-mean-square voltage of acoustic emission, while the jumplike development of deformation, by high-amplitude single acoustic signals. The amplitude of single acoustic signals correlates with the strain rate.

Plotnikov, V. A.; Makarov, S. V.

2008-04-01

407

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

408

Detector signal correction method and system  

DOEpatents

Corrective factors are applied so as to remove anomalous features from the signal generated by a photoconductive detector, and to thereby render the output signal highly linear with respect to the energy of incident, time-varying radiation. The corrective factors may be applied through the use of either digital electronic data processing means or analog circuitry, or through a combination of those effects.

Carangelo, Robert M. (Glastonbury, CT); Duran, Andrew J. (Oviedo, FL); Kudman, Irwin (Boca Raton, FL)

1995-07-11

409

Self-correcting quantum computers  

NASA Astrophysics Data System (ADS)

Is the notion of a quantum computer (QC) resilient to thermal noise unphysical? We address this question from a constructive perspective and show that local quantum Hamiltonian models provide self-correcting QCs. To this end, we first give a sufficient condition on the connectedness of excitations for a stabilizer code model to be a self-correcting quantum memory. We then study the two main examples of topological stabilizer codes in arbitrary dimensions and establish their self-correcting capabilities. Also, we address the transversality properties of topological color codes, showing that six-dimensional color codes provide a self-correcting model that allows the transversal and local implementation of a universal set of operations in seven spatial dimensions. Finally, we give a procedure for initializing such quantum memories at finite temperature.

Bombin, H.; Chhajlany, R. W.; Horodecki, M.; Martin-Delgado, M. A.

2013-05-01

410

Corrective Jaw Surgery  

MedlinePLUS

... course of treatment that is best for you. Correction of Common Dentofacial Deformities Correcting an Open Bite: ... and their supporting soft and hard tissues Surgical Correction of Maxillofacial Skeletal Deformities Cleft and Craniofacial Surgery ...

411

A New Concept of the Power Quality Temperature Factor and Its Experimental Verification  

Microsoft Academic Search

One of the features of ship power systems is the presence of different power quality disturbances, such as frequency and voltage root-mean-square (rms) value deviations, unbalance, and voltage waveform distortions. The disturbances (including their synergy) cause an increase in the windings temperature of marine induction machines that are exposed to overheating, even if the voltage parameters fulfill the requirements of

Piotr Gnacinski; Janusz Mindykowski; Tomasz Tarasiuk

2008-01-01

412

Temperature-dependent regulation of a heterologous transcriptional activation domain fused to yeast heat shock transcription factor.  

PubMed Central

The heat shock transcription factor (HSF) of the yeast Saccharomyces cerevisiae is posttranslationally modified. At low growth temperatures, it activates transcription of heat shock genes only poorly; after shift to high temperatures, it activates transcription readily. In an effort to elucidate the mechanism of this regulation, we constructed a series of HSF-VP16 fusions that join the HSF DNA-binding domain to the strong transcriptional activation domain from the VP16 gene of herpes simplex virus. Replacement of the endogenous C-terminal transcriptional activation domain with that of VP16 generates an HSF derivative that exhibits behavior reminiscent of HSF itself: low transcriptional activation activity at normal growth temperature and high activity after heat shock. HSF can thus restrain the activity of the heterologous VP16 transcriptional activation domain. To determine what is required for repression of activity at low temperature, we deleted portions of HSF from this HSF-VP16 fusion to map the regulatory domain. We also isolated point mutations that convert the HSF-VP16 fusion into a constitutive transcriptional activator. We conclude that the central, evolutionarily conserved domain of HSF, encompassing the DNA-binding and multimerization domains, contains a major determinant of temperature-dependent regulation. Images

Bonner, J J; Heyward, S; Fackenthal, D L

1992-01-01

413

The role of the Arabidopsis FUSCA3 transcription factor during inhibition of seed germination at high temperature  

PubMed Central

Background Imbibed seeds integrate environmental and endogenous signals to break dormancy and initiate growth under optimal conditions. Seed maturation plays an important role in determining the survival of germinating seeds, for example one of the roles of dormancy is to stagger germination to prevent mass growth under suboptimal conditions. The B3-domain transcription factor FUSCA3 (FUS3) is a master regulator of seed development and an important node in hormonal interaction networks in Arabidopsis thaliana. Its function has been mainly characterized during embryonic development, where FUS3 is highly expressed to promote seed maturation and dormancy by regulating ABA/GA levels. Results In this study, we present evidence for a role of FUS3 in delaying seed germination at supraoptimal temperatures that would be lethal for the developing seedlings. During seed imbibition at supraoptimal temperature, the FUS3 promoter is reactivated and induces de novo synthesis of FUS3 mRNA, followed by FUS3 protein accumulation. Genetic analysis shows that FUS3 contributes to the delay of seed germination at high temperature. Unlike WT, seeds overexpressing FUS3 (ML1:FUS3-GFP) during imbibition are hypersensitive to high temperature and do not germinate, however, they can fully germinate after recovery at control temperature reaching 90% seedling survival. ML1:FUS3-GFP hypersensitivity to high temperature can be partly recovered in the presence of fluridone, an inhibitor of ABA biosynthesis, suggesting this hypersensitivity is due in part to higher ABA level in this mutant. Transcriptomic analysis shows that WT seeds imbibed at supraoptimal temperature activate seed-specific genes and ABA biosynthetic and signaling genes, while inhibiting genes that promote germination and growth, such as GA biosynthetic and signaling genes. Conclusion In this study, we have uncovered a novel function for the master regulator of seed maturation, FUS3, in delaying germination at supraoptimal temperature. Physiologically, this is important since delaying germination has a protective role at high temperature. Transcriptomic analysis of seeds imbibed at supraoptimal temperature reveal that a complex program is in place, which involves not only the regulation of heat and dehydration response genes to adjust cellular functions, but also the activation of seed-specific programs and the inhibition of germination-promoting programs to delay germination.

2012-01-01

414

Corrections de temperature sur les coefficients d'activite calcules selon la TIS. (Adjustment of activity coefficients as a function of changes in temperature, using the SIT. SIT: Specific Interaction Theory).  

National Technical Information Service (NTIS)

The aim of this work is to propose and to check approximations to calculate from only a few experimental measurements, ionic strength, I, and temperature, T, influences on Gibbs energy, G, redox formal potential, E, and standard equilibrium constant, K. S...

E. Giffaut P. Vitorge H. Capdevila

1993-01-01

415

Activity-based anorexia: Ambient temperature has been a neglected factor  

Microsoft Academic Search

Activity-based anorexia refers to the self-starvation of rats exposed to experimental conditions that combine restricted access\\u000a to food with access to an activity wheel. This paper compares previous studies of this phenomenon in relation to the ambient\\u000a temperatures (AT) that were employed. On this basis, and from some more direct evidence, we argue that AT is an important,\\u000a but neglected,

Emilio Gutiérrez; Reyes Vázquez; R. A. Boakes

2002-01-01

416

Growth, condition factor, and bioenergetics modeling link warmer stream temperatures below a small dam to reduced performance of juvenile steelhead  

USGS Publications Warehouse

We investigated the growth and feeding performance of juvenile steelhead Oncorhynchus mykiss using field measures and bioenergetics modeling. Juvenile steelhead populations were sampled from mid-June through August 2004 at study sites upstream and downstream of Hemlock Dam. The growth and diet of juvenile steelhead were determined for a warm (summer) and subsequent (late summer) transitional period at each study site. Empirical data on the growth and diet of juvenile steelhead and mean daily temperatures were used in a bioenergetics model to estimate the proportion of maximum consumption achieved by juvenile steelhead by site and period. Modeled estimates of feeding performance were better for juvenile steelhead at the upstream compared to the downstream site during both periods. The median condition factor of juvenile steelhead did not change over the summer at the upstream site, but showed a significant decline over time at the downstream site. A negative trend in median condition factor at the downstream site supported bioenergetics modeling results that suggested the warmer stream temperatures had a negative impact on juvenile steelhead. Bioenergetics modeling predicted a lower feeding performance for juvenile steelhead rearing downstream compared to upstream of Hemlock Dam although food availability appeared to be limited at both study sites during the warm period. Warmer water temperatures, greater diel variation, and change in diel pattern likely led to the reduced feeding performance and reduced growth, which could have affected the overall survival of juvenile steelhead downstream of Hemlock Dam. ?? 2010 by the Northwest Scientific Association.

Sauter, S. T.; Connolly, P. J.

2010-01-01

417

Abnormal production of tumor necrosis factor (TNF) -- alpha and clinical efficacy of the TNF inhibitor etanercept in a patient with PAPA syndrome [corrected].  

PubMed

We report a family with pyogenic sterile arthritis, pyoderna and acne syndrome (PAPA). The proband presented several episodes of sterile pyogenic arthritis and became unresponsive to glucocorticoids. After treatment with the tumor necrosis factor inhibitor etanercept, the disease underwent rapid and sustained clinical remission. Production of tumor necrosis factor-alpha by mononuclear cells of the proband and of the affected relatives was abnormally elevated. PMID:15580218

Cortis, Elisabetta; De Benedetti, Fabrizio; Insalaco, Antonella; Cioschi, Stefania; Muratori, Flaminia; D'Urbano, Leila E; Ugazio, Alberto G

2004-12-01

418

A priori estimation of scale and overall anisotropic temperature factors from the Patterson origin peak.  

PubMed

An idea due to D. Rogers [Computing Methods in Crystallography (1965), edited by J. S. Rollett, pp. 117-148. Oxford: pergamon Press] has been developed and implemented. The method is an advantageous alternative to Wilson plot or K-curve scaling of intensity data. On the relative experimental scale the structure factor can be written in matrix notation as F(h) = kappa -1 sigma j fj(h) exp (2 pi ih tau xj) exp (-h tau bjh); and the squared structure-factor magnitude can be written as magnitude of F(h)2 = kappa -2 exp (-2h tau bh) [sigma j fj2+ 2 sigma j sigma k greater than jfjfk exp [2 pi ih tau (xj-xk)

Blessing, R H; Langs, D A

1988-09-01

419

Microstructural factors influencing critical-current densities of high-temperature superconductors  

SciTech Connect

Microstructural defects are the primary determining factors for the values of critical current densities in superconductors. A review is made to assess, (1) what would be the maximum achievable critical-current density in the oxide superconductors if nearly ideal pinning sites were introduced? and (2) what types of pinning defects are currently introduced in these superconductors and how effective are these in pinning the vortices? Only the case where the applied field is parallel to the c-axis is considered here.

Suenaga, M.

1992-12-31

420

Microstructural factors influencing critical-current densities of high-temperature superconductors  

SciTech Connect

Microstructural defects are the primary determining factors for the values of critical current densities in superconductors. A review is made to assess, (1) what would be the maximum achievable critical-current density in the oxide superconductors if nearly ideal pinning sites were introduced and (2) what types of pinning defects are currently introduced in these superconductors and how effective are these in pinning the vortices Only the case where the applied field is parallel to the c-axis is considered here.

Suenaga, M.

1992-01-01

421

BELIEF IN CORRECTNESS  

Microsoft Academic Search

In developing information technology, you want assurance that systems are secure and reliable. Correctness is an attribute that one strives for in order to achieve those goals, but you cannot have assurance or security without correctness. We discuss methods used to achieve correctness, focusing on weaknesses and approaches that management might take to increase belief in correctness. Formal methods, simulation,

Marshall D. Abrams; Marvin V. Zelkowitz

422

NICKEL CORRECTS MOUSE-EAR.  

Technology Transfer Automated Retrieval System (TEKTRAN)

The mouse-ear disorder of pecan is a long standing problem that has resisted a solution for nearly a 100 years. Information is discussed relating to how mouse-ear is induced and what orchard managers can do to correct the disorder. Orchard management factors such as soil pH, soil moisture, amount ...

423

[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

424

Study of Inactivation Factors in Low Temperature Surface-wave Plasma Sterilization  

NASA Astrophysics Data System (ADS)

In this study we investigated the low temperature surface-wave plasma sterilization of directly and indirectly exposed Geobacillus stearothermophilus spores with a large-volume microwave plasma device. The air-simulated gas mixture was used to produce the plasma. The water vapor addition to the gas mixture improved the sterilization efficiency significantly. The effect of ultraviolet photons produced along with plasma to inactivate the spores was studied using a separate chamber, which was evacuated to less than one mTorr and was observed that spores were sterilized within 60 min. The scanning electron microscopy images revealed no significant changes in the actual size of the spores with that of untreated spores despite the survival curve shown that the spores were inactivated.

Singh, Mrityunjai Kumar; Xu, Lei; Ogino, Akihisa; Nagatsu, Masaaki

425

Extreme-mass-ratio inspiral corrections to the angular velocity and redshift factor of a mass in circular orbit about a Kerr black hole  

NASA Astrophysics Data System (ADS)

This is the first of two papers on computing the self-force in a radiation gauge for a particle of mass m moving in circular, equatorial orbit about a Kerr black hole. In the extreme-mass-ratio inspiral (EMRI) framework, with mode-sum renormalization, we compute the renormalized value of the quantity H?(1)/(2)h??u?u?, gauge-invariant under gauge transformations generated by a helically symmetric gauge vector; here, h?? is the metric perturbation, u? the particle’s 4-velocity. We find the related order m correction to the particle’s angular velocity at fixed renormalized redshift (and to its redshift at fixed angular velocity), each of which can be written in terms of H. The radiative part of the metric perturbation is constructed from a Hertz potential that is extracted from the Weyl scalar by an algebraic inversion T. S. Keidl , Phys. Rev. D 82, 124012 (2010). We then write the spin-weighted spheroidal harmonics as a sum over spin-weighted spherical harmonics Y?ms and use mode-sum renormalization to find the renormalization coefficients by matching a series in L=?+1/2 to the large-L behavior of the expression for H. The nonradiative parts of the perturbed metric associated with changes in mass and angular momentum are calculated in the Kerr gauge.

Shah, Abhay G.; Friedman, John L.; Keidl, Tobias S.

2012-10-01

426

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

NASA Astrophysics Data System (ADS)

Ice clouds are an important yet largely unvalidated component of weather forecasting and climate models, but radar offers the potential to provide the necessary data to evaluate them. First in this paper, coordinated aircraft in situ measurements and scans by a 3-GHz radar are presented, demonstrating that, for stratiform midlatitude ice clouds, radar reflectivity in the Rayleigh-scattering regime may be reliably calculated from aircraft size spectra if the “Brown and Francis” mass size relationship is used. The comparisons spanned radar reflectivity values from -15 to +20 dBZ, ice water contents (IWCs) from 0.01 to 0.4 g m-3, and median volumetric diameters between 0.2 and 3 mm. In mixed-phase conditions the agreement is much poorer because of the higher-density ice particles present. A large midlatitude aircraft dataset is then used to derive expressions that relate radar reflectivity and temperature to ice water content and visible extinction coefficient. The analysis is an advance over previous work in several ways: the retrievals vary smoothly with both input parameters, different relationships are derived for the common radar frequencies of 3, 35, and 94 GHz, and the problem of retrieving the long-term mean and the horizontal variance of ice cloud parameters is considered separately. It is shown that the dependence on temperature arises because of the temperature dependence of the number concentration “intercept parameter” rather than mean particle size. A comparison is presented of ice water content derived from scanning 3-GHz radar with the values held in the Met Office mesoscale forecast model, for eight precipitating cases spanning 39 h over southern England. It is found that the model predicted mean IWC to within 10% of the observations at temperatures between -30° and -10°C but tended to underestimate it by around a factor of 2 at colder temperatures.

Hogan, Robin J.; Mittermaier, Marion P.; Illingworth, Anthony J.

2006-02-01

427

77 FR 72199 - Technical Corrections; Correction  

Federal Register 2010, 2011, 2012, 2013

...Region I office, correcting authority citations and typographical and spelling errors...that is cited in one of the authority citations in the final rule. DATES: The correction...authority that is cited in the authority citation for part 171 of Title 10 of the...

2012-12-05

428

Factors influencing the radiative surface temperature of grey seal (Halichoerus grypus) pups during early and late lactation.  

PubMed

The aim of this study was to examine the variation in body surface temperature of grey seal (Halichoerus grypus) pups throughout lactation in response to different environmental conditions. Radiative surface temperatures (T (r), degrees C) of pups were measured on the Isle of May (56 degrees 11'N, 02 degrees 33'W), southeast Scotland from 29 October to 25 November 2003. Records were obtained from a total of 60 pups (32 female and 28 male) from three different pupping sites during early and late lactation. Pups were sheltered from high wind speeds but air temperature, humidity and solar radiation at pupping sites were similar to general meteorological conditions. The mean T (r) of all pups was 15.8 degrees C (range 7.7-29.7 degrees C) at an average air temperature of 10.2 degrees C (range 6.5-13.8 degrees C). There was no difference in the mean T (r) of pups between early and late lactation. However, the T (r) varied between different regions of the body with hind flippers on average 2-6 degrees C warmer than all other areas measured. There was no difference in mean T (r) of male and female pups and pup body mass did not account for the variation in T (r) during early or late lactation. Throughout the day there was an increase in the T (r) of pups and this explained 20-28% of the variation in T (r) depending on stage of lactation. There was no difference in the mean T (r) of pups between pupping sites or associated with different substrate types. Wind speed and substrate temperature had no effect on the T (r) of pups. However, solar radiation, air temperature and relative humidity accounted for 48% of the variation in mean T (r) of pups during early lactation. During late lactation air temperature and solar radiation alone accounted for 43% of the variation in T (r). These results indicate that environmental conditions explain only some of the variation in T (r) of grey seal pups in natural conditions. Differences in T (r) however indicate that the cost of thermoregulation for pups will vary throughout lactation. Further studies examining intrinsic factors such as blubber thickness and activity levels are necessary before developing reliable biophysical models for grey seals. PMID:16001186

McCafferty, D J; Moss, S; Bennett, K; Pomeroy, P P

2005-07-05

429

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

430

Temperature-jump effect for cylindrical resonators with low quality factors  

NASA Astrophysics Data System (ADS)

The temperature-jump and slip-velocity at the resonator wall cause boundary perturbations to resonance frequencies. For cylindrical resonators, the perturbation contributes larger uncertainties to the Boltzmann constant than for spherical resonators. This report describes the analytical investigations on the shift of resonance frequency from the thermal and viscous accommodation effects. The expression for calculating the thermal accommodation coefficient from the speed of sound data using cylindrical resonators is presented. The thermal accommodation coefficient between argon gas and the bearing steel wall is estimated to be 0.97+/-0.03. The squared speeds of sound at zero pressure c02 in argon for various modes calculated from different thermal accommodation coefficients are compared. The 0.03 uncertainty for the thermal accommodation coefficient causes relative deviations of c02 of 0.6×10-6 and 0.8×10-6 in cylindrical resonators with length of 130 mm and 65 mm, respectively. The effect on c02 is reduced if the measurements from the two cylindrical resonators are analyzed together.

Feng, X. J.; Lin, H.; Zhang, J. T.

2013-09-01

431

Neutron Scattering Facility for the Measurement of Light Quenching Factors of Dark Matter Detectors at Low Temperatures  

NASA Astrophysics Data System (ADS)

The light yield of scintillating crystals which is quantified by light Quenching Factors (QFs) strongly depends on the kind of interaction in the crystal. For Dark Matter experiments like CRESST the precise knowledge of QFs is crucial for the discrimination of background events from possible WIMP signals. At the tandem accelerator of the Maier-Leibnitz-Laboratorium (MLL) in Garching a low-temperature scattering facility was set up, which in its current phase aims at the determination of the QFs of O, Ca, and W in CaWO4 crystals as used in the CRESST experiment. A CRESST detector module consists of a 300 g CaWO4 target crystal operated as a phonon detector and a separate silicon-on-sapphire (SOS) light detector to detect the corresponding scintillation light simultaneously. In order to disentangle the light yield corresponding to O, Ca and W recoils, monoenergetic neutrons (11 MeV) produced by the accelerator are scattered off an especially developed CRESST-like detector module, which is operated at mK temperatures in a dilution refrigerator. Arrays of liquid-scintillator detectors placed at fixed scattering angles allow one to identify the recoiling nuclei by a neutron time-of-flight measurement. The unique facility is suited for the characterization of different detector materials and will be a powerful tool also for the future multi-material experiment EURECA. We report on the experimental approach, the low-temperature setup and present first results.

Strauss, R.; Ciemniak, C.; Deuter, G.; von Feilitzsch, F.; Gütlein, A.; Hagn, H.; Jochum, J.; Lanfranchi, J.-C.; Lepelmeier, J.; Pfister, S.; Potzel, W.; Roth, S.; Rottler, K.; Sailer, C.; Scholl, S.; von Sivers, M.; Thalhammer, U.; Wawoczny, S.; Willers, M.; Usherov, I.

2012-06-01

432

Optimal Countrates for Deadtime Corrections  

SciTech Connect

The high x-ray flux available at synchrotron radiation sources can cause nonlinearities in photon-counting detectors unless deadtime corrections are employed. We compute the uncertainties associated with several common deadtime-correction formulas. At lower countrates, statistical noise dominates the error in the measured countrates; at higher countrates, the dominating factors are saturation of the response and uncertainty in the value of the deadtime parameter. In between, a range of countrates exists in which the signal-to-noise ratio can be optimized for photon-counting experiments.

Walko, D. A.; Arms, D. A.; Dufresne, E. M.; Landahl, E. C.

2010-08-02

433

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

434

Use of recombinant activated factor VII for reduction of perioperative blood loss during elective surgical correction of spine deformity in a Jehovah's Witness. Case report.  

PubMed

Planned surgical procedures at patients who refuse allogenic blood transfusion because of religious convictions are important problem, not only medical but also ethical and juristical. At the study authors report the successful use of activated recombinant factor VII (rFVIIa) for the reduction of perioperative blood loss in four years old child - Jehovah's Witness, who had planned Torode kyphectomy. Applied perioperative management together with preparing to surgery with erythropoietin allowed for reduction of blood loss and avoiding of blood transfusion. Authors state, that appropriate perioperative proceeding makes a possibility of safe surgical procedures also at patients who refuse the transfusion. PMID:21057153

K?cka, Katarzyna; K?cki, Wojciech; Merak, Joanna; B??ka, Adam

435

On anharmonic and pressure corrections to the equilibrium isotopic constants for minerals  

NASA Astrophysics Data System (ADS)

Specifies of the calculations of the reduced isotopic partition function ratios (?-factor) of minerals are discussed. Comparative calculations in the framework of the fully harmonic, quasi-harmonic, and intrinsic anharmonic approximations show minor anharmonic corrections to the harmonic values of the