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1

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

SciTech Connect

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

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

2010-10-15

2

Body mass and corrective factor: impact on temperature-based death time estimation.  

PubMed

Model-based methods play an important role in temperature-based death time determination. The most prominent method uses Marshall and Hoare's double exponential model with Henssge's parameter determination. The formulae contain body mass as the only non-temperature parameter. Henssge's method is well established since it can be adapted to non-standard cooling situations varying the parameter body mass by multiplying it with the corrective factor. The present study investigates the influence of measurement errors of body mass m as well as of variations of the corrective factor c on the error of the Marshall and Hoare-Henssge death time estimator t (D). A formula for the relative error of t (D) as a function of the relative error of m is derived. Simple approximations of order 1 and 0 nevertheless yield acceptable results validated by Monte Carlo simulations. They also provide the rule of thumb according to which the quotient of the standard deviations D(t (D)) of the estimated death time and D(m) of the body mass is equal to the quotient of the estimated death time t (D) and the body mass m (D(t (D))/D(m) ? t (D)/m). Additionally, formulae and their approximations are derived to quantify the influence of Henssge's body mass corrective factor c on death time estimation. In a range of body masses between 50 and 150 kg, the relative variation of the body mass corrective factor is approximately equal to the relative variation of the death time (?t (D) = (t (D)/c)?c). This formula is applied and compared to computations and to experimental cooling data with good results. PMID:21286739

Hubig, Michael; Muggenthaler, Holger; Sinicina, Inga; Mall, Gita

2011-05-01

3

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

4

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

NASA Astrophysics Data System (ADS)

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

Butterfield, D.; Gardiner, T.

2014-08-01

5

Biberman 'free-bound' continuum correction factor approximation for line-to-continuum temperature diagnostic of aluminium laser plasma  

NASA Astrophysics Data System (ADS)

The applicability and versatility of plasma diagnostics to various fields is constrained by numerous challenges. Spectroscopic coefficients are crucial for successful implementation of a particular diagnostic technique. The 'line-to-continuum' technique, which is used to determine the electron temperature (Te), is applicable to a large range of wavelengths and spatio-temporal coordinates within a laser plasma plume via emission spectroscopy. To successfully utilize this technique, a number of spectroscopic coefficients are required. The Biberman 'free-bound' continuum correction factor (?fb) is a required constant for the line-to-continuum technique which displays a strong temperature and wavelength dependence for ? < 450 nm. Approximation of ?fb over a discrete temperature range for aluminium is achieved using space- and time-resolved visible emission spectroscopy in the optical range (? = 350-470 nm). Complementary temperature diagnostics are undertaken to determine the excitation temperature (Texc) and the ionization temperature (Tionz). Convergence in the calculated Texc and Tionz spatial profiles is identified as regions of local thermal equilibrium. Calculated average temperatures (Tavg) over the range T ~ 20-34 × 103 K are determined and used to approximate values for the Biberman 'free-bound' continuum correction factor for Al III (453 nm) and elucidate its temperature dependence.

Yeates, P.

2011-04-01

6

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

E-print Network

THEORETICAL FULL PONER CORRECTION FACTORS AS RELATED TO CHANGES IN AvLBIENF TFAPERATURE, PRESSURE AND ABSOLUTE HUMIDITY FOR AIRCRAI'T TURBINE ENGINES A Thesi: bv Michael Antoun Raphael Submitted to tbe Gradua 2 College of Texas A&M University... IN AMBIENT TEMPERATURE, PRESSURF. AND ABSOLUTE HUMIDITY FOR AIRCRAFT TURBINE ENGINES (August 1969) Michael Antoun Raphael B. S. (Mechanical Engineering) Texas A&M University Directed by: Professor Stanley H, Lowy ABSTRACT Power losses in aircraft gas...

Raphael, Michel Antoun

1969-01-01

7

Optimal power factor correction  

SciTech Connect

This paper discusses the different parameters affecting the economic feasibility of power factor correction. It will be shown that the specific costs of the transmission and compensation elements as well as those of the electric energy and power losses have a decisive influence on the achievable overall saving. After formulating an objective function representing this overall saving, taking also the load factor into account an analytical approach to the determination of the optimal size of the compensation equipment is presented. A generalized chart is given which enables the designer to know whether the power factor correction is feasible or not under any circumstances. Also, the most suitable degree of reactive power compensation can be directly found. The results obtained from a digital program are also given to indicate the sensitivity of the optimal compensation factor to changes in system parameters such as the specific energy loss cost and the annual rate of interest and depreciation. Moreover, the good agreement of the results of the digital computation with those determined using the suggested simple generalized chart, could be realized.

Mostafa, M. (Electrical and Computer Engineering Dept., College of Engineering and Petroleum, Kuwait Univ. (KW))

1988-08-01

8

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

9

Correcting horsepower measurements to a standard temperature  

NASA Technical Reports Server (NTRS)

This report discusses the relation between the temperature of the air at the entrance to the carburetor and the power developed by the engine. Its scope is limited to a consideration of the range of temperatures likely to result from changes of season, locality, or altitude, since its primary aim is the finding of a satisfactory basis for correcting power measurements to a standard temperature. The tests upon which this report is based were made upon aviation engines in the Altitude Laboratory of the Bureau of Standards. From the results of over 1,600 tests it is concluded that if calculations be based on the assumption that the indicated horsepower of an engine varies inversely as the square root of the absolute temperature of the carburetor air the values obtained will check closely experimental measurements. The extent to which this relationship would be expected from theoretical considerations is discussed and some suggestions are given relative to the use of this relationship in correcting horsepower measurements. (author)

Sparrow, Stanwood W

1925-01-01

10

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

11

Scale-factor corrections in large ring lasers  

NASA Astrophysics Data System (ADS)

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

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

2007-08-01

12

A novel single-phase power factor correction scheme  

Microsoft Academic Search

A single-phase power factor correction scheme is proposed based on the power flow analysis. It is found that the conventional power factor correction (PFC) circuit must be designed to handle the rated power, although its purpose is only for power factor correction. With the proposed scheme, the PFC circuit is in parallel with the major power flow path, thus reducing

Yimin Jiang; Fred C. Lee; Guichao Hua; Wei Tang

1993-01-01

13

Accuracy in Mooring Motion Temperature Corrections CHRISTOPHER S. MEINEN  

E-print Network

Accuracy in Mooring Motion Temperature Corrections CHRISTOPHER S. MEINEN Atlantic Oceanographic). Hydrographic data are used to estimate the accuracy with which moored temperature sensors in the Gulf Stream-mean-square pressure deflection of 150 dbar, accuracy limits of up to 0.7°C on the "corrected" temperatures are appli

14

An Analysis of Ionization Correction Factors in Planetary Nebulae  

NASA Astrophysics Data System (ADS)

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

Delgado-Inglada, G.

2014-04-01

15

Diffuse band correction factors for short time intervals  

Microsoft Academic Search

Diffuse radiation measured with a shading band requires a correction factor to compensate for the diffuse sky radiation blocked by the band. A set of empirically derived correction factors for Albany, New York is presented. The factors decrease the error by as much as 25% as compared to the Drummond method under some conditions when one minute data are analyzed.

D. W. Spencer; B. S. Oettinger; R. Stewart

1982-01-01

16

LC compensators for power factor correction of nonlinear loads  

Microsoft Academic Search

A method is presented for finding the optimum fixed LC compensator for power factor correction of nonlinear loads where both source voltage and load current harmonics are present. The LC combination is selected because pure capacitive capacitors alone would not sufficiently correct the power factor. Optimization minimizes the transmission loss, maximizes the power factor, and maximizes the efficiency. The performance

M. M. AbdelAziz; E. E.-D. AbouEl-Zahab; A. M. Ibrahim; A. F. Zobaa

2004-01-01

17

Effective temperature scale and bolometric corrections from 2MASS photometry  

Microsoft Academic Search

We present a method to determine effective temperatures, angular semi-diameters and bolometric corrections for population I and II FGK type stars based on V and 2MASS IR photometry. Accurate calibration is accomplished by using a sample of solar analogues, whose average temperature is assumed to be equal to the solar effective temperature of 5777 K. By taking into account all

E. Masana; C. Jordi; I. Ribas

2006-01-01

18

Correction of high-frequency noise-temperature inaccuracies  

NASA Technical Reports Server (NTRS)

Deep-space mission data rates to Earth are limited by the system operating noise-temperature (T(sub op)) performance of the DSN. This article addresses some of the techniques and definitions used for measuring and reporting the effective noise temperature of receivers (Te) and T(sub op) of the DSN's ground receiving systems. Calibration loads are used to measure T(sub op) of the DSN antennas. At 32 GHz, a calibration load cooled to 2-K physical temperature requires a correction of 0.67 K to determine the noise temperature. Using corrected noise temperature for the calibration loads results in the correct values for T(sub op) such that the total system noise power can be defined by Pn = kT(sub op) B, as required for DSN telecommunications design control tables. T(sub op) and Te should not be converted to equivalent physical temperatures.

Stelzreid, C. T.

1992-01-01

19

Corrected Hawking Temperature in Snyder's Quantized Space-time  

NASA Astrophysics Data System (ADS)

In the quantized space-time of Snyder, generalized uncertainty relation and commutativity are both included. In this paper we analyze the possible form for the corrected Hawking temperature and derive it from the both effects. It is shown that the corrected Hawking temperature has a form similar to the one of noncommutative geometry inspired Schwarzschild black hole, however with an requirement a/?{? }? 1/0.015 for the noncommutative parameter 𝜃 and the minimal length a.

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

2014-11-01

20

Temperature-Corrected Model of Turbulence in Hot Jet Flows  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

21

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

22

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

23

Temperature Corrected Turbulence Model for High Temperature Jet Flow  

Microsoft Academic Search

It is well known that the two -equation turbulence models under predict mixing in the shear layer for high temperature jet flows. These turbulence models were developed and calibrated for room temperature, low Mach number, and pla ne mixing layer flows. In the present study, four existing modifications to the two -equation turbulence model are implemented in PAB3D and their

Khaled S. Abdol-Hamid; Steven J. Massey

2003-01-01

24

Estimating an image sensor's temperature for darksignal-correction  

NASA Astrophysics Data System (ADS)

An approach for darksignal-correction is presented that uses a model of each pixel's darksignal, which depends on the sensor's settings (integration time and gain) and its temperature. It is shown how one can improve the outcome of such a darksignal-correction strategy by using the darksignal of some pixels in order to compute an estimate of the sensor's temperature. Experimental results indicate that the darksignals' dependency on temperature and gain is more complex than considered in up-to-date darksignal models. In this paper it is shown how one can cope with this complex behaviour when estimating the temperature out of the darksignal. Experimental results indicate, that our method yields better results than using temperature measurements of dedicated temperature sensors.

Achatzi, Julian; Fischer, Gregor; Zimmer, Volker; Paulus, Dietrich

2014-03-01

25

Second Order Corrections to QED Coupling at Low Temperature  

E-print Network

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

Samina S. Masood; Mahnaz Q. Haseeb

2006-12-11

26

Single phase unity power factor correction circuits with coupled inductance  

Microsoft Academic Search

The idea of using coupled inductance in single-phase diode rectifier power factor correction circuits and the influence of the coupling factor on the current ripple are discussed. The circuit proposed for current shaping consists of a boost converter connected to the line and a buck converter connected to the output capacitor

Miro MilanoviC; F. Mihalic; K. Jezernik; U. Milutinovic

1992-01-01

27

A Multipoint Correction Method for Environmental Temperature Changes in Airborne Double-Antenna Microwave Radiometers  

PubMed Central

This manuscript describes a new type Ka-band airborne double-antenna microwave radiometer (ADAMR) designed for detecting atmospheric supercooled water content (SCWC). The source of the measurement error is investigated by analyzing the model of the system gain factor and the principle of the auto-gain compensative technique utilized in the radiometer. Then, a multipoint temperature correction method based on the two-point calibration method for this radiometer is proposed. The multipoint temperature correction method can eliminate the effect of changes in environmental temperature by establishing the relationship between the measurement error and the physical temperatures of the temperature-sensitive units. In order to demonstrate the feasibility of the correction method, the long-term outdoor temperature experiment is carried out. The multipoint temperature correction equations are obtained by using the least square regression method. The comparison results show that the measuring accuracy of the radiometer can be increased more effectively by using the multipoint temperature correction method. PMID:24787639

Sun, Jian; Zhao, Kai; Jiang, Tao

2014-01-01

28

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

NASA Technical Reports Server (NTRS)

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

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

1939-01-01

29

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

30

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

31

Correction of particulate matter concentrations to reference temperature and pressure conditions  

SciTech Connect

The 1997 revisions to the particulate matter NAAQS included changes in the reporting method of observed concentrations. Pollutant concentration data contained in EPA`s Aerometric Information Retrieval System (AIRS) prior to the 1997 revisions had been required to be reported in units corrected to standard temperature and pressure (25{degree} C, 760 mm Hg). This requirement was removed so that, in the new regulations, the particulate matter data will be reported to AIRS at local temperature and pressure. This work analyzes the impact of this revision to the spatial and temporal pattern of PM10 concentrations. The influence of pressure and temperature individually on the correction of US PM10 concentrations was first examined over a seasonal time scale. The two correction factors were then combined to produce a total correction factor and, subsequently, uncorrected PM10 concentration maps at local conditions were derived. The temperature correction was further inspected for purposes of determining differences between quarterly and monthly aggregations. Particulate matter concentrations expressed in terms of local pressure may be between 10 and 25 percent lower than those reported at standard pressure with the largest decreases occurring in the high elevation areas of the western US The temperature correction is most influential in the Northeast and Upper Midwest during the cold months with PM concentrations up to 10% higher than those reported at standard temperature. Combing the temperature and pressure corrections results in PM10 increases up to 5% in the Northeast and Upper Midwest during the winter and decreases up to 25% in the West, with the summer months experiencing greater decreases than the winter.

Falke, S.R.; Husar, R.B. [Washington Univ., St. Louis, MO (United States). Center for Air Pollution Impact and Trend Analysis

1998-12-31

32

Radiative Equilibrium and Temperature Correction in Monte Carlo Radiation Transfer  

E-print Network

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

J. E. Bjorkman; Kenneth Wood

2001-03-15

33

An EGSnrc investigation of correction factors for ion chamber dosimetry  

NASA Astrophysics Data System (ADS)

Radiation dosimetry is used to quantify the dose delivered during radiation therapy by using ionization chambers with several correction factors. Knowledge of these factors is needed at well below the 1% level in order to maintain the overall uncertainty on the reference dosimetry near 1-2%. The small magnitude of the corrections renders measurements very difficult. Monte Carlo calculations are widely used for this purpose, however they require very low statistical uncertainties. A new user-code, CSnrc, for the EGSnrc Monte Carlo system is described. CSnrc uses a correlated sampling variance reduction technique to reduce the uncertainty for dose ratio calculations. Compared to an existing EGSnrc user-code from which it was developed, CSnrc shows gains in efficiency of up to a factor of 64 and achieves much lower statistical uncertainties on correction factors than previously published. CSnrc is used to compute the central electrode correction factor, Pcel, in a broader range of beams than previously used and at the depths relevant to modern protocols. For photon beams, the CSnrc values compare well with the values used in dosimetry protocols whereas for electron beams, CSnrc shows up to a 0.2% correction for a graphite electrode, a correction currently ignored by dosimetry protocols. The difference from currently used values is slightly less for an aluminum electrode. CSnrc is also used to compute the wall correction factor, P wall. For cylindrical chambers in photon beams, the CSnrc calculations are compared to the currently used Almond-Svensson formalism and differ from this formalism by as much as 0.8%. The CSnrc values are used to explain some previously published experiments showing problems with Pwall . For electron beams, where dosimetry protocols assume a Pwall of unity, CSnrc calculations show a correction as large as 0.6%. For parallel-plate chambers, there is little information available regarding Pwall in photon beams. CSnrc shows corrections of over 2% for some chambers. In electron beams, Pwall has been assumed to be unity, despite previously published evidence suggesting otherwise. CSnrc shows that for some chambers at lower energies, Pwall is nearly 1.02.

Buckley, Lesley A.

34

Improved induction-heating inverter with power factor correction  

Microsoft Academic Search

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

Hugo Calleja; R. Ordonez

1999-01-01

35

Solar Correction Factors of Building Envelope in Tebei  

E-print Network

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

Wang, D.; Tang, M.

2006-01-01

36

Radiative corrections to the Casimir effect at nonzero temperatures  

SciTech Connect

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

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

1986-10-01

37

Eucken correction in high-temperature gases with electronic excitation  

SciTech Connect

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

Istomin, V. A.; Kustova, E. V., E-mail: elena-kustova@mail.ru; Mekhonoshina, M. A. [Saint Petersburg State University, 28 Universitetsky pr., 198504 Saint Petersburg (Russian Federation)] [Saint Petersburg State University, 28 Universitetsky pr., 198504 Saint Petersburg (Russian Federation)

2014-05-14

38

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

39

Temperature Correction of Pressure-Sensitive Paints Simplified  

NASA Technical Reports Server (NTRS)

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

Bencic, Timothy J.

2000-01-01

40

Recent Developments in Single-Phase Power Factor Correction  

Microsoft Academic Search

The development of single-phase power factor correction (PFC) technologies was traditionally driven by the need for computers, telecommunication, lighting, and other electronic devices and systems to meet harmonic current limits defined by IEC 61000-3-2 and other regulatory standards. Recently, several new applications have emerged as additional drivers for the development of the technologies. One such application is commercial transport airplanes

Zhonghui BingI; Min Chen; S. K. T. Miller; Y. Nishida; Jian Sun

2007-01-01

41

Temperature Correction to Casimir-Lifshitz Free Energy at Low Temperatures: Semiconductors  

E-print Network

The Casimir force and free energy at low temperatures has been the subject of focus for some time. We calculate the temperature correction to the Casimir-Lifshitz free energy between two parallel plates made of dielectric material possessing a constant conductivity at low temperatures, described through a Drude-type dielectric function. For the transverse magnetic (TM) mode such a calculation is new. A further calculation for the case of the TE mode is thereafter presented which extends and generalizes previous work for metals. A numerical study is undertaken to verify the correctness of the analytic results.

Simen A. Ellingsen; Iver Brevik; Johan S. H\\oye; Kimball A. Milton

2008-07-23

42

Temperature corrections in the Priestley-Taylor equation of evaporation  

NASA Astrophysics Data System (ADS)

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

Szilagyi, Jozsef

2014-11-01

43

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

SciTech Connect

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

Schweng, H.K.; Boehm, H.M. (Institut fuer Theoretische Physik, Johannes Kepler Universitaet Linz, A-4040 Linz-Auhof (Austria))

1993-07-15

44

Production of element correction factors for thermoluminescent dosimeters  

SciTech Connect

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

Plato, P.; Miklos, J.

1985-11-01

45

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

PubMed

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

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

2014-07-01

46

Quality correction factors of composite IMRT beam deliveries: Theoretical considerations  

SciTech Connect

Purpose: In the scope of intensity modulated radiation therapy (IMRT) dosimetry using ionization chambers, quality correction factors of plan-class-specific reference (PCSR) fields are theoretically investigated. The symmetry of the problem is studied to provide recommendable criteria for composite beam deliveries where correction factors are minimal and also to establish a theoretical limit for PCSR delivery k{sub Q} factors. Methods: The concept of virtual symmetric collapsed (VSC) beam, being associated to a given modulated composite delivery, is defined in the scope of this investigation. Under symmetrical measurement conditions, any composite delivery has the property of having a k{sub Q} factor identical to its associated VSC beam. Using this concept of VSC, a fundamental property of IMRT k{sub Q} factors is demonstrated in the form of a theorem. The sensitivity to the conditions required by the theorem is thoroughly examined. Results: The theorem states that if a composite modulated beam delivery produces a uniform dose distribution in a volume V{sub cyl} which is symmetric with the cylindrical delivery and all beams fulfills two conditions in V{sub cyl}: (1) the dose modulation function is unchanged along the beam axis, and (2) the dose gradient in the beam direction is constant for a given lateral position; then its associated VSC beam produces no lateral dose gradient in V{sub cyl}, no matter what beam modulation or gantry angles are being used. The examination of the conditions required by the theorem lead to the following results. The effect of the depth-dose gradient not being perfectly constant with depth on the VSC beam lateral dose gradient is found negligible. The effect of the dose modulation function being degraded with depth on the VSC beam lateral dose gradient is found to be only related to scatter and beam hardening, as the theorem holds also for diverging beams. Conclusions: The use of the symmetry of the problem in the present paper leads to a valuable theorem showing that k{sub Q} factors of composite IMRT beam deliveries are close to unity under specific conditions. The theoretical limit k{sub Q{sub p{sub c{sub s{sub r,Q{sub m{sub s{sub r}{sup f{sub p}{sub c}{sub s}{sub r},f{sub m}{sub s}{sub r}}}}}}}}}=1 is determined based on the property of PCSR deliveries to provide a uniform dose in the target volume. The present approach explains recent experimental observations and proposes ideal conditions for IMRT reference dosimetry. The result of this study could potentially serve as a theoretical basis for reference dosimetry of composite IMRT beam deliveries or for routine IMRT quality assurance.

Bouchard, Hugo [Departement de radio-oncologie, Centre hospitalier de l'Universite de Montreal (CHUM), 1560 Sherbrooke est, Montreal, Quebec H2L 4M1 (Canada)

2012-11-15

47

Small-signal modeling of boost power-factor correction controllers  

Microsoft Academic Search

Electric power is delivered most efficiently when the load draws current at unity power factor. Traditional rectifier\\/filter power supplies, however, draw currents that are highly non-sinusoidal and thus display a low power factor. An alternative approach, known as offline power factor correction (PFC), achieves near-unity power factor by eliminating the filter capacitor and using switchmode power converter techniques. Power-factor correction

David M. Beams; Sriram Boppana

2010-01-01

48

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

49

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

...2014-07-01 false NOX intake-air humidity and temperature corrections...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES...Requirements § 1065.670 NOX intake-air humidity and temperature...

2014-07-01

50

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

51

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

52

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

53

Testing and Evaluation of a Power Factor Correction for Power-Savings Potential  

E-print Network

Power factor correction (PFC) is an important technology that can be used to enhance power quality. It was noted that the power factor was low for packaged air-conditioning (PAC) units utilized in residential buildings in Kuwait. To study...

Alotaibi, A.

2011-01-01

54

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

SciTech Connect

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

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

2012-07-01

55

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

NASA Technical Reports Server (NTRS)

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

Richards, W. Lance

1996-01-01

56

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

57

High magnetic field corrections to resistance thermometers at low temperatures  

Microsoft Academic Search

We present a reliable method to account for the magnetoresistance of resistance sensors which are used as thermometers in many low temperature (T<=20 K) experiments carried out in high magnetic fields (to 31 T). To apply the method, a set of isothermal magnetoresistance data, and a zero magnetic field temperature calibration are first necessary. A simple algorithm, which uses this

B. Zhang; J. S. Brooks; J. A. A. J. Perenboom; S.-Y. Han; J. S. Qualls

1999-01-01

58

High magnetic field corrections to resistance thermometers at low temperatures  

Microsoft Academic Search

We present a reliable method to account for the magnetoresistance of resistance sensors which are used as thermometers in many low temperature (T?20 K) experiments carried out in high magnetic fields (to 31 T). To apply the method, a set of isothermal magnetoresistance data, and a zero magnetic field temperature calibration are first necessary. A simple algorithm, which uses this

B. Zhang; J. S. Brooks; J. A. A. J. Perenboom; S.-Y. Han; J. S. Qualls

1999-01-01

59

High magnetic field corrections to resistance thermometers at low temperatures  

NASA Astrophysics Data System (ADS)

We present a reliable method to account for the magnetoresistance of resistance sensors which are used as thermometers in many low temperature (T?20 K) experiments carried out in high magnetic fields (to 31 T). To apply the method, a set of isothermal magnetoresistance data, and a zero magnetic field temperature calibration are first necessary. A simple algorithm, which uses this data set, can then be applied to compute the temperature from the measured resistance at any field. The method is particularly useful for temperature dependent measurements at fixed field, or where, in cases where the temperature may change unpredictably during a change in magnetic field. We apply this method to the treatment of data in two separate experiments with the two different thermometers, RuO2 (below 1 K) and Cernox (above 1 K) sensors, respectively.

Zhang, B.; Brooks, J. S.; Perenboom, J. A. A. J.; Han, S.-Y.; Qualls, J. S.

1999-04-01

60

A 230 KV power factor correction installation taking into account the low voltage filters  

SciTech Connect

Power factor is an important component for utilities in maintaining the overall efficiency of the power delivery. Utilities encourage industrial customers to provide their own power factor correction for low power factor loads. At the end of large capacity transmission lines utilities tend to provide power factor correction through shunt capacitor banks. With increased number of filter banks in low voltage distribution systems for power factor correction and harmonic filtering, installation of high voltage capacitor banks require careful considerations. In this paper, the study results of a practical 105 MVAR, 230 kV capacitor bank is discussed. The effect of the existing 13.8 kV filter on the installation of the high voltage power factor correction capacitors is examined. The frequency domain analysis to evaluate various resonant frequencies are also discussed.

Natarajan, R. [ABB Power T and D Co., Raleigh, NC (United States); Hale, E. [Black and Veatch Construction, Inc., Lake Oswego, OR (United States); Ashmore, S. [ABB HV Capacitors, Saint-Laurent (Canada); Larsson, K. [ABB, Quebec (Canada)

1999-11-01

61

Weld pool penetration measurement using ultrasound with thermal gradient correction factors  

NASA Astrophysics Data System (ADS)

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

Anderton, John Martin

62

Correcting for focal-plane-array temperature dependence in  

E-print Network

-board calibration sources or temperature stabilization, such as sensing in agriculture and food processing,6). This paper describes a method for sta- bilizing the camera's response through software processing: infrared imaging; radiometry; infrared systems; infrared detectors. Paper 121438SS received Oct. 2, 2012

Shaw, Joseph A.

63

K-Scale Correction and Percentile Norms for MMPI-168 Factor Scores.  

ERIC Educational Resources Information Center

Derived appropriate K-corrections for Minnesota Multiphasic Personality Inventory-168 factor scales and a general psychopathology screening scale (PSY). Determined percentile distributions of K-corrected scales in a normal sample (N=1438) and constructed a percentile profile sheet to facilitate clinical use (N=1048). Examined validity of the…

Overall, John E.; And Others

1983-01-01

64

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

E-print Network

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

Lindner, Douglas K.

65

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

NASA Technical Reports Server (NTRS)

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

Schliestett, George Van

1934-01-01

66

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

Federal Register 2010, 2011, 2012, 2013

...Correction Factor for Room Air Conditioners AGENCY: Office of the General...testing procedures for room air conditioners. The petition seeks temporary...testing procedures for room air conditioners. Public comment is...

2010-11-26

67

A Detailed Analysis of the Geometric Shower Radiant Altitude Correction Factor  

NASA Astrophysics Data System (ADS)

The heart of the visible meteor Zenithal Hourly Rate (ZHR) formula is the correction factor for shower radiant angular altitude (or zenith angle). This correction factor is primarily an effect of the geometry between the incident shower meteor flux vector and the oblique target area presented by the atmospheric "meniscus" visible to a single observer on the surface of the Earth. Presented in this paper is a detailed analysis of the full geometric portion of this correction factor, for apparent radiant altitudes both above and below the local horizon, and with the radiant zenith attraction effect also included. This analysis opens the way toward a better understanding of the non-geometric effects within the complete correction factor, which must currently be derived empirically.

Richardson, J.

1999-12-01

68

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

NASA Astrophysics Data System (ADS)

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

Šolc, Jaroslav; Sochor, Vladimír

2014-06-01

69

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 ...

70

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

71

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

72

Correction improves z-factor values for high gas density  

SciTech Connect

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 by the authors.

Borges, P.R. (Petrobras, Rio de Janeiro (BR))

1991-03-04

73

Power factor correction; Economic feasibility and technical limitations  

SciTech Connect

This paper gives the results of a parameter sensitivity analysis and discusses the feasibility of reactive power compensation applied to low power factor loads. After enumerating its different economical and technical advantages, the effectiveness of the load compensation in reducing the total annual cost of the power system is formulated. Using available optimization techniques, either analytical or by using a generalized chart, the optimal degree of reactive power compensation, for a certain combination of the power system technical and economical data is identified. This is followed by a sensitivity analysis showing the feasible range of compensation as well as the pay-back index. The paper includes a discussion of the effect of the compensation on the network voltage profile.

Saied, M.M. (Kuwait Univ. (Kuwait).)

1989-01-01

74

Solid velocity correction schemes for a temperature transforming model for convection phase change  

Microsoft Academic Search

Purpose – To study the effects of velocity correction schemes for a temperature transforming model (TTM) for convection controlled solid-liquid phase-change problem. Design\\/methodology\\/approach – The effects of three different solid velocity correction schemes, the ramped switch-off method (RSOM), the ramped source term method (RSTM) and the variable viscosity method (VVM), on a TTM for numerical simulation of convection controlled solid-liquid

Zhanhua Ma; Yuwen Zhang

2006-01-01

75

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

76

Temperature correction of arterial blood-gas parameters: A comparative review of methodology.  

PubMed

The need for accurate clinical diagnosis and appropriate intervention requires that a modern blood-gas laboratory have the means to correct for significant discrepancies between patient temperature and the temperature at which in vitro blood samples are analyzed. Recent advances in mini- and microcomputer technology permit application of any or all of the correction formulas above at modest cost and minimal inconvenience (See the Appendix). An expanded program for a TI-59 desk-top calculator and P-100C printer which gives labeled hard-copy readout of temperature-corrected pH, PCO2, PO2, and hemoglobin saturation values, as well as bicarbonate concentration and in vivo base excess is in daily clinical use in our operating room and is available from the authors upon request. PMID:6791530

Andritsch, R F; Muravchick, S; Gold, M I

1981-09-01

77

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.

78

On the Factorization of Collinear and Infrared Singularities in QCD Corrections to the Mikaelian Zero  

NASA Astrophysics Data System (ADS)

The method of Smilga and Vysotsky is used in the Feynman gauge to extract IR/Coll. singularities from one loop corrections to a general process in both scalar QED and massless QCD. These results are used to demonstrate that a Mikaelian zero factor multiplies the IR/Coll. singular terms in O(? _s) corrections to W^- rightarrow bar{u}d ? and related processes containing an amplitude zero.

Reid, J. H.

1986-01-01

79

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

80

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

NASA Astrophysics Data System (ADS)

In spite of dense meteorological observation conducting over South Korea (The average distance between stations: ~ 12.7km), the detailed topographical effect is not reflected properly due to its mountainous terrains and observation sites mostly situated on low altitudes. A model represents such a topographical effect well, but due to systematic biases in the model, the general temperature distribution is sometimes far different from actual observation. This study attempts to produce a detailed mean temperature distribution for South Korea through a method combining dynamical downscaling and statistical correction. For the dynamical downscaling, a multi-nesting technique is applied to obtain 3-km resolution data with a focus on the domain for the period of 10 years (1999-2008). For the correction of systematic biases, a perturbation method divided into the mean and the perturbation part was used with a different correction method being applied to each part. The mean was corrected by a weighting function while the perturbation was corrected by the self-organizing maps method. The results with correction agree well with the observed pattern compared to those without correction, improving the spatial and temporal correlations as well as the RMSE. In addition, they represented detailed spatial features of temperature including topographic signals, which cannot be expressed properly by gridded observation. Through comparison with in-situ observation with gridded values after objective analysis, it was found that the detailed structure correctly reflected topographically diverse signals that could not be derived from limited observation data. We expect that the correction method developed in this study can be effectively used for the analyses and projections of climate downscaled by using region climate models. Acknowledgements This work was carried out with the support of Korea Meteorological Administration Research and Development Program under Grant CATER 2012-3083 and Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under Grant Project No. PJ009353, Republic of Korea. Reference Ahn, J.-B., Lee, J.-L., and Im, E.-S., 2012: The reproducibility of surface air temperature over South Korea using dynamical downscaling and statistical correction, J. Meteor. Soc. Japan, 90, 493-507, doi: 10.2151/jmsj.2012-404

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

2013-12-01

81

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

82

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

83

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

Microsoft Academic Search

A new satellite sea surface temperature (SST) algorithm is developed that uses nearly coincident measurements from the microwave special sensor microwave imager (SSM\\/I) to correct for atmospheric moisture attenuation of the infrared signal from the advanced very high resolution radiometer (AVHRR). This new SST algorithm is applied to AVHRR imagery from the South Pacific and Norwegian seas, which are then

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

1994-01-01

84

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

Microsoft Academic Search

A new satellite sea surface temperature (SST) algorithm is developed that uses nearly coincident measurements from the microwave special sensor microwave imager (SSM\\/I) to correct for atmospheric moisture attenuation of the infrared signal from the advanced very high resolution radiometer (AVHRR). This new SST algorithm is applied to AVHRR imagery from the South Pacific and Norwegian sea, which are then

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

1994-01-01

85

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

86

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...

87

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

88

The Leading Correction to the Thomas-Fermi Model at Finite Temperature  

E-print Network

The semi-classical approach leading to the Thomas-Fermi (TF) model provides a simple universal thermodynamic description of the electronic cloud surrounding the nucleus in an atom. This model is known to be exact at the limit of $Z\\rightarrow\\infty$, i.e., infinite nuclear charge, at finite density and temperature. Motivated by the zero-temperature case, we show in the current letter that the correction to TF due to quantum treatment of the strongly bound inner-most electrons, for which the semi-classical approximation breaks, scales as $Z^{-1/3}$, with respect to the TF solution. As such, it is more dominant than the quantum corrections to the kinetic energy, as well as exchange and correlation, which are known to be suppressed by $Z^{-2/3}$. We conjecture that this is the leading correction for this model. In addition, we present a different free energy functional for the TF model, and a successive functional that includes the strongly bound electrons correction. We use this corrected functional to derive a...

Segev, Eyal

2014-01-01

89

Factors affecting SFHR gene correction efficiency with single-stranded DNA fragment  

SciTech Connect

A 606-nt single-stranded (ss) DNA fragment, prepared by restriction enzyme digestion of ss phagemid DNA, improves the gene correction efficiency by 12-fold as compared with a PCR fragment, which is the conventional type of fragment used in the small fragment homologous replacement method [H. Tsuchiya, H. Harashima, H. Kamiya, Increased SFHR gene correction efficiency with sense single-stranded DNA, J. Gene Med. 7 (2005) 486-493]. To reveal the characteristic features of this gene correction with the ss DNA fragment, the effects on the gene correction in CHO-K1 cells of the chain length, 5'-phosphate, adenine methylation, and transcription were studied. Moreover, the possibility that the ss DNA fragment is integrated into the target DNA was examined with a radioactively labeled ss DNA fragment. The presence of methylated adenine, but not the 5'-phosphate, enhanced the gene correction efficiency, and the optimal length of the ss DNA fragment ({approx}600 nt) was determined. Transcription of the target gene did not affect the gene correction efficiency. In addition, the target DNA recovered from the transfected CHO-K1 cells was radioactive. The results obtained in this study indicate that length and adenine methylation were important factors affecting the gene correction efficiency, and that the ss DNA fragment was integrated into the double-stranded target DNA.

Tsuchiya, Hiroyuki [Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Sapporo 060-0812 (Japan); CREST, Japan Science and Technology (Japan); Harashima, Hideyoshi [Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Sapporo 060-0812 (Japan); CREST, Japan Science and Technology (Japan); Kamiya, Hiroyuki [Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Sapporo 060-0812 (Japan) and CREST, Japan Science and Technology (Japan)]. E-mail: hirokam@pharm.hokudai.ac.jp

2005-11-04

90

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

91

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

92

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

NASA Astrophysics Data System (ADS)

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

Kelly, R. E.; Elliott, C.

2012-12-01

93

A Current-Sensorless Digital Controller for Active Power Factor Correction Control Based on Kalman Filters  

E-print Network

A Current-Sensorless Digital Controller for Active Power Factor Correction Control Based on Kalman, by replacing the sensor with a Kalman filter, which is essentially a stochastic observer. Experimental results-power techniques are undesirable and the current sensor is too expensive. A Kalman filter [7] can be used

Kimball, Jonathan W.

94

A Research on Economic Factors Affecting China's Tax Growth Based on Panel Error Correction Model  

Microsoft Academic Search

This paper discusses how various kinds of major economic factors affect China's tax growth. We apply the panel unit root testing, panel cointegration testing and panel-based error correction models to analyze the long-term stable relationship among tax growth, GDP growth, optimization of industrial structure and import for 30 provinces during 1994- 2008 periods. The empirical results show that in the

Sun Jian; Tong Jinzhi

2011-01-01

95

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

96

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

NASA Technical Reports Server (NTRS)

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

Cooper, D. I.; Asrar, G.

1989-01-01

97

Many-Electron QED Corrections to the g Factor of Lithiumlike Ions  

NASA Astrophysics Data System (ADS)

A rigorous QED evaluation of the two-photon exchange corrections to the g factor of lithiumlike ions is presented. The screened self-energy corrections are calculated for the intermediate-Z region, and its accuracy for the high-Z region is essentially improved in comparison with that of previous calculations. As a result, the theoretical accuracy of the g factor of lithiumlike ions is significantly increased. The theoretical prediction obtained for the g factor of Si2811+ gth=2.000 889 892(8) is in an excellent agreement with the corresponding experimental value gexp=2.000 889 889 9(21) [A. Wagner et al., Phys. Rev. Lett. 110, 033003 (2013)].

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

2014-06-01

98

Identifying and Correcting Urban Bias in Regional Time Series: Surface Temperature in China's Northern Plains  

Microsoft Academic Search

A detailed study of urban bias in surface temperatures of China's northern plains is described. Temperatures of climatological surface stations were examined using a statistical rank-score procedure that allows screening of the data without knowledge of the station history information. Time series found to exhibit large potential discontinuities (i.e., those introduced as a result of nonclimatic factors such as observation

David A. Portman

1993-01-01

99

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

NASA Astrophysics Data System (ADS)

The application of small photon fields in modern radiotherapy requires the determination of total scatter factors Scp or field factors \\Omega ^{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 cm2 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 cm2, 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 cm2, 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.

Czarnecki, D.; Zink, K.

2013-04-01

100

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

101

Bias correction of temperature and precipitation data for regional climate model application to the Rhine basin  

NASA Astrophysics Data System (ADS)

The Hydrology and Quantitative Water Management group of Wageningen University is involved in the EU research project NeWater. The objective of this project is to develop tools which provide medium range hydrological predictions by coupling catchment-scale water balance models and ensembles from mesoscale climate models. The catchment-scale distributed hydrological model used in this study is the Variable Infiltration Capacity (VIC) model. This hydrological model in combination with an ensemble from the climate model ECHAM5 (developed by Max Plank Institute für Meteorologie (MPI-M), Hamburg) is being used to evaluate the effects of climate change on the hydrological regime of the Rhine basin and to assess the uncertainties involved in the ensembles from the climate model used in this study. Three future scenarios (2001-2100) are used in this study, which are downscaled ECHAM5 runs which were forced by the IPCC carbon emission scenarios B1, A1B and A2. A downscaled ECHAM5 "Climate of the 20th Century" run (1951-2000) is used as the reference climate. Downscaled ERA15 data is used to calibrate the VIC model. Downscaling of both the ECHAM5 and ERA15 model was carried out with the regional climate model REMO at MPI-M to a resolution of 0.088 degrees. The assessment of uncertainties involved in the climate model ensembles is performed by comparing the model (ECHAM5-REMO and ERA15-REMO) ensemble precipitation and temperature data with observations. This resulted in the detection of a bias in both the downscaled reference climate data and downscaled ERA15 data. A bias-correction has been applied to both the downscaled ERA15 data and the reference climate data. This bias-correction corrects for the mean and coefficient of variation for precipitation and the mean and standard deviation for temperature. The results of the applied bias-correction are analyzed spatially and temporally. Despite the fact that the bias-correction only uses two parameters, the coefficient of variation, standard deviation and mean of the bias-corrected data sets showed significant improvements for both precipitation and temperature. Even statistics that were not taken into account in the bias-correction, such as the fraction of wet days, the lag-one autocorrelation and the exceedance probabilities have improved as well.

Terink, W.; Hurkmans, R. T. W. L.; Uijlenhoet, R.; Torfs, P. J. J. F.; Warmerdam, P. M. M.

2009-04-01

102

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

NASA Astrophysics Data System (ADS)

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 the IAEA protocols TRS-381 (1997) and TRS-398 (2000) disagree, in particular at large depths. Calculations of the electron fluence have been done, using the Monte Carlo code PENELOPE, in semi-infinite phantoms of water and common plastic materials (PMMA, clear polystyrene, A-150, polyethylene, Plastic waterTM and Solid waterTM (WT1)). The simulations have been carried out for monoenergetic electron beams of 6, 10 and 20 MeV, as well as for a realistic clinical beam. The simulated fluence correction factors differ from the values in the AAPM and IAEA recommendations by up to 2%, and are in better agreement with factors obtained by Ding et al (1997 Med. Phys. 24 161-76) using EGS4. Our Monte Carlo calculations are also in good accordance with ?waterplastic values measured by using an almost perturbation-free ion chamber. The important interdependence between depth- and fluence-scaling corrections for plastic phantoms is discussed. Discrepancies between the measured and the recommended values of ?waterplastic may then be explained considering the different depth-scaling rules used.

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

2003-05-01

103

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

104

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

105

[Interpretation of postmortem digoxin levels: evaluating a "corrective factor" for postmortem blood digoxin concentration].  

PubMed

Interpretation of postmortem serum digoxin levels is made difficult above all by a possible prefinal or postmortem rise in digoxin concentrations in the blood. To compensate for this postmortem increase, Eriksson et al. (1984) divided the level of postmortem digoxin in femoral venous blood by a factor of 1.5; in the opinion of these authors, postmortem digoxin levels still exceeding "therapeutic levels" after division by 1.5 are an index of digoxin overdose. The diagnostic value of this "correction factor" was investigated. In 56 cases with documented digoxin medication, samples of postmortem femoral venous blood were taken and the level of digoxin determined. In none of the cases had there been a clinical diagnosis of digoxin intoxication. Fifty percent of the measured values were above "therapeutic levels" (0.7 ng/ml to 2.2 ng/ml). Following division by 1.5, 20% of the cases still showed levels exceeding 2.2 ng/ml; the highest "corrected" value was 4.44 ng/ml. Taking into account the length of time between final dosage and death, individual differences in sensitivity to digitalis glycoside, and the complexity of ante- and postmortem dispersion processes, we concluded for the cases we studied that an (undetected) digoxin overdose was not even likely in those cases whose postmortem values after division by 1.5 lie above "therapeutic levels". The "correction factor" proposed by Eriksson et al. (1984) is only of limited diagnostic value; at best the "corrected" values can give an approximate indication of the corresponding antemortem serum digoxin concentrations. In particular, "corrected" values only a little above "therapeutic levels" could not confirm suspicion of an overdose with sufficient certainty. PMID:2264399

Ritz, S; Kaatsch, H J

1990-01-01

106

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

107

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

108

An integral battery charger with Power Factor Correction for electric scooter  

Microsoft Academic Search

An integral battery charger is proposed for an electric scooter with Li-Ion batteries and Interior-permanent-magnet (IPM) traction motor. The battery charger is integrated in the power hardware of the scooter, with the IPM traction drive that operates as three-phase dc-dc converter with power factor correction (PFC) capability. The control of the PFC battery charger is also integrated into the traction

Gianmario Pellegrino; Eric Armando; Paolo Guglielmi

2009-01-01

109

An Integral Battery Charger With Power Factor Correction for Electric Scooter  

Microsoft Academic Search

This paper presents an integral battery charger for an electric scooter with high voltage batteries and interior-permanent-magnet motor traction drive. The battery charger is derived from the power hardware of the scooter, with the ac motor drive that operates as three-phase boost rectifier with power factor correction capability. The control of the charger is also integrated into the scooter control

Gianmario Pellegrino; Eric Armando; Paolo Guglielmi

2010-01-01

110

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

111

ccSVM: correcting Support Vector Machines for confounding factors in biological data classification  

PubMed Central

Motivation: Classifying biological data into different groups is a central task of bioinformatics: for instance, to predict the function of a gene or protein, the disease state of a patient or the phenotype of an individual based on its genotype. Support Vector Machines are a wide spread approach for classifying biological data, due to their high accuracy, their ability to deal with structured data such as strings, and the ease to integrate various types of data. However, it is unclear how to correct for confounding factors such as population structure, age or gender or experimental conditions in Support Vector Machine classification. Results: In this article, we present a Support Vector Machine classifier that can correct the prediction for observed confounding factors. This is achieved by minimizing the statistical dependence between the classifier and the confounding factors. We prove that this formulation can be transformed into a standard Support Vector Machine with rescaled input data. In our experiments, our confounder correcting SVM (ccSVM) improves tumor diagnosis based on samples from different labs, tuberculosis diagnosis in patients of varying age, ethnicity and gender, and phenotype prediction in the presence of population structure and outperforms state-of-the-art methods in terms of prediction accuracy. Availability: A ccSVM-implementation in MATLAB is available from http://webdav.tuebingen.mpg.de/u/karsten/Forschung/ISMB11_ccSVM/. Contact: limin.li@tuebingen.mpg.de; karsten.borgwardt@tuebingen.mpg.de PMID:21685091

Li, Limin; Rakitsch, Barbara; Borgwardt, Karsten

2011-01-01

112

Detecting and correcting the bias of unmeasured factors using perturbation analysis: a data-mining approach  

PubMed Central

Background The randomized controlled study is the gold-standard research method in biomedicine. In contrast, the validity of a (nonrandomized) observational study is often questioned because of unknown/unmeasured factors, which may have confounding and/or effect-modifying potential. Methods In this paper, the author proposes a perturbation test to detect the bias of unmeasured factors and a perturbation adjustment to correct for such bias. The proposed method circumvents the problem of measuring unknowns by collecting the perturbations of unmeasured factors instead. Specifically, a perturbation is a variable that is readily available (or can be measured easily) and is potentially associated, though perhaps only very weakly, with unmeasured factors. The author conducted extensive computer simulations to provide a proof of concept. Results Computer simulations show that, as the number of perturbation variables increases from data mining, the power of the perturbation test increased progressively, up to nearly 100%. In addition, after the perturbation adjustment, the bias decreased progressively, down to nearly 0%. Conclusions The data-mining perturbation analysis described here is recommended for use in detecting and correcting the bias of unmeasured factors in observational studies. PMID:24499374

2014-01-01

113

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

SciTech Connect

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

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

1987-03-01

114

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

PubMed

The melting temperature (T(m)) 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 I(h)-liquid coexisting system. Dispersion corrections to BLYP lower T(m) to about 360 K, a large improvement over the value of T(m) > 400 K previously obtained with the original BLYP functional under the same simulation conditions. For TTM3-F, T(m) = 248 K from classical molecular dynamics simulations. PMID:21456638

Yoo, Soohaeng; Xantheas, Sotiris S

2011-03-28

115

Using satellite altimetry to correct mean temperature and salinity fields derived from Argo floats in the ocean regions around Australia  

NASA Astrophysics Data System (ADS)

We present results from a suite of methods using in situ temperature and salinity data, and satellite altimetric observations to obtain an enhanced set of mean fields of temperature, salinity (down to 2000-m depth) and steric height (0/2000 m) for a time-specific period (1992-2007). Firstly, the improved global sampling resulting from the introduction of the Argo program, enables a representative determination of the large-scale mean oceanic structure. However, shortcomings in the coverage remain. High variability western boundary current eddy fields, continental slope and shelf boundaries may all be below their optimal sampling requirements. We describe a simple method to supplement and improve standard spatial interpolation schemes and apply them to the available data within the waters surrounding Australia (100°E-180°W; 50°S-10°N). This region includes a major current system, the East Australian Current (EAC), complex topography, unique boundary currents such as the Leeuwin Current, and large ENSO related interannual variability in the southwest Pacific. We use satellite altimetry sea level anomalies (SLA) to directly correct sampling errors in in situ derived mean surface steric height and subsurface temperature and salinity fields. The surface correction is projected through the water column (using an empirical model) to modify the mean subsurface temperature and salinity fields. The errors inherent in all these calculations are examined. The spatial distribution of the barotropic-baroclinic balance is obtained for the region and a 'baroclinic factor' to convert the altimetry SLA into an equivalent in situ height is determined. The mean fields in the EAC region are compared with independent estimates on repeated XBT sections, a mooring array and full-depth CTD transects.

Ridgway, K. R.; Dunn, J. R.

2010-09-01

116

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

117

Online Bias Correction of ARGO Temperature and Salinity Data in the GMAO Ocean Ensemble Kalman Filter  

NASA Astrophysics Data System (ADS)

Past experiments with the online bias correction (OBC) algorithm used in the GMAO ocean ensemble Kalman fiter (EnKF) have demonstrated the importance of applying OBC when sea surface height (SSH) anomalies are assimilated. In this case, OBC is necessary to update the SSH climatology used to reconstruct the SSH field. While correcting the model climatology by means of OBC is less important when in situ temperature, salinity or current data are assimilated because these data are not ingested in their anomalous form, analyses reveal that the corresponding model fields are systematically biased, even though a standard (i.e., without OBC) assimilation can partially compensate the biases. While we were always interested in assessing the usefulness of OBC in the assimilation of temperature or salinity data, we were prevented in doing so until recently because the OBC algorithm is ineffective with sparse observations. The near exponential increase in the number of assimilate-able ARGO measurements has recently changed that reality. Hence, we examine how applying OBC in the assimilation of ARGO temperature and salinity data affects the quality of the analysis products.

Keppenne, C. L.; Rienecker, M. M.; Kovach, R.

2007-05-01

118

A correction factor for positive degree-day modeling of ice sheet surface melt under changing orbital configurations  

NASA Astrophysics Data System (ADS)

Positive degree-day (PDD) models have commonly been used to approximate continental ice sheet surface melt for the last two decades. The approach is advantageous in that it approximates present-day surface melt reasonably well and it is computationally very efficient. However, the empirical coefficients used to translate PDDs into melt are tuned to present-day conditions and thus may not be appropriate for use under other orbital configurations. Here we explore to what extent the current formulation of a PDD melt equation affects melt estimates for different levels of orbital-scale insolation changes. We find that insolation anomalies can cause large discrepancies between melt calculated using PDDs and using a simple energy-balance equation. However, higher temperatures reduce the effect of the insolation anomaly since its relative importance decreases in the energy balance. We introduce a correction factor for the PDD model that accounts for changes in insolation and improves the agreement of melt estimated by the two different methods. A particular feature of this factor is that it is fully consistent with current PDD models for present-day insolation. The new insolation-corrected PDD formulation is further tested with transient simulations of the Greenland ice sheet for the Eemian.

Robinson, Alexander; Goelzer, Heiko; Huybrechts, Philippe

2013-04-01

119

Single-stage power factor correction ac-dc converter based on continuous input current charge-pump topologies  

Microsoft Academic Search

This paper presents a new single-stage power factor corrected (PFC) AC-DC converter. The topology is based on CIC-CPPFC (continuous input current charge-pump power factor correction) technique, achieving continuous conduction mode (CCM) input current with high power factor and reduced current ripple by using a coupled inductor, meeting IEC 61000-3-2 regulations for wide load range without additional input filter. The converter

Cícero S. Postiglione; Arnaldo J. Perin; Claudinor B. Nascimento

2008-01-01

120

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

SciTech Connect

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

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

2009-07-15

121

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

PubMed

Temperature measurement by thermocouples is prone to errors due to conduction and radiation losses and therefore has to be corrected for precise measurement. The temperature dependent emissivity of the thermocouple wires is measured by the use of thermal infrared camera. The measured emissivities are found to be 20%-40% lower than the theoretical values predicted from theory of electromagnetism. A transient technique is employed for finding the heat transfer coefficients for the lead wire and the bead of the thermocouple. This method does not require the data of thermal properties and velocity of the burnt gases. The heat transfer coefficients obtained from the present method have an average deviation of 20% from the available heat transfer correlations in literature for non-reacting convective flow over cylinders and spheres. The parametric study of thermocouple error using the numerical code confirmed the existence of a minimum wire length beyond which the conduction loss is a constant minimal. Temperature of premixed methane-air flames stabilised on 16 mm diameter tube burner is measured by three B-type thermocouples of wire diameters: 0.15 mm, 0.30 mm, and 0.60 mm. The measurements are made at three distances from the burner tip (thermocouple tip to burner tip/burner diameter = 2, 4, and 6) at an equivalence ratio of 1 for the tube Reynolds number varying from 1000 to 2200. These measured flame temperatures are corrected by the present numerical procedure, the multi-element method, and the extrapolation method. The flame temperatures estimated by the two-element method and extrapolation method deviate from numerical results within 2.5% and 4%, respectively. PMID:23464237

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

2013-02-01

122

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

PubMed

Quantitative analysis of the atmospheric effects on observations made by the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) has been performed. The differences between observed brightness temperatures at the top of the atmosphere and at the bottom of the atmosphere were analyzed using a database of simulated observations, which were configured to replicate AMSR-E data. The differences between observed brightness temperatures at the top of the atmosphere and land surface-emitted brightness temperatures were also computed. Quantitative results show that the atmosphere has different effects on brightness temperatures in different AMSR-E channels. Atmospheric effects can be neglected at 6.925 and 10.65 GHz, when the standard deviation is less than 1 K. However, at other frequencies and polarizations, atmospheric effects on observations should not be neglected. An atmospheric correction algorithm was developed at 18.7 GHz vertical polarization, based on the classic split-window algorithm used in thermal remote sensing. Land surface emission can be estimated with RMSE = 0.99 K using the proposed method. Using the known land surface emissivity, Land Surface Temperature (LST) can be retrieved. The RMSE of retrieved LST is 1.17 K using the simulated data. PMID:23842351

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

2013-07-01

123

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

2012-04-01

124

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

125

Correction factors for parallel-plate chambers used in plastic phantoms in electron dosimetry  

NASA Astrophysics Data System (ADS)

In electron beam dosimetry using parallel-plate chambers solid phantoms are sometimes necessary. To obtain the dose to water from the ionization obtained in the solid phantom, fluence correction factors and perturbation factors have to be applied. In this study fluence factors in a perturbation free geometry have been determined experimentally for common phantom materials. Wall perturbation factors for simulated Attix, NACP, and Roos chambers have also been determined for the same materials. Comparative Monte Carlo calculations have been performed using the EGS4 Monte Carlo code. Comparison with data in newly published protocols such as IAEA and IPEMB shows an agreement with the results obtained in this paper to within 1%, demonstrating that the data published in these protocols may be used with reasonable accuracy if recommended phantoms are used. The results also show that if unsuitable phantom materials are used, the wall perturbation factors may differ for different chambers and for different phantom materials by more than 3% and perturbation factors have to be considered in order to obtain a high accuracy in the dose determination.

Nilsson, B.; Montelius, A.; Andreo, P.; Johansson, J.

1997-11-01

126

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Temperature derating factor (T) for steel pipe...STANDARDS Pipe Design § 192.115 Temperature derating factor (T ) for steel pipe. The temperature derating factor to be used in the...

2013-10-01

127

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

NASA Technical Reports Server (NTRS)

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

Blankenship, Clay; Zavodsky, Brad; Blackwell, William

2014-01-01

128

Evaluation of drag correction factor for spheres settling in associative polymers  

Microsoft Academic Search

Drag correction factors are calculated for the creeping motion of spheres descending in various associative polymers of different\\u000a concentration with various sphere-container ratios and Weissenberg numbers. The simple-shear rheology and linear viscoelasticity\\u000a of these polymeric fluids have been previously presented and modeled with the BMP (Bautista–Manero–Puig) equation of state\\u000a (Mendoza-Fuentes et al., Phys Fluids 21:033104, 2009). The drag on the sphere

Arturo J. Mendoza-Fuentes; Octavio Manero; Roberto Zenit

2010-01-01

129

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

NASA Astrophysics Data System (ADS)

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

Collell, Julien; Galliero, Guillaume

2014-05-01

130

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

SciTech Connect

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

Collell, Julien; Galliero, Guillaume, E-mail: guillaume.galliero@univ-pau.fr [Laboratoire des Fluides Complexes et leurs Réservoirs, UMR-5150 with CNRS and Total, Université de Pau et des Pays de l'Adour, BP 1155, 64013 Pau (France)] [Laboratoire des Fluides Complexes et leurs Réservoirs, UMR-5150 with CNRS and Total, Université de Pau et des Pays de l'Adour, BP 1155, 64013 Pau (France)

2014-05-21

131

Correction: Towards improved precision in the quantification of surface-enhanced Raman scattering (SERS) enhancement factors: a renewed approach.  

PubMed

Correction for 'Towards improved precision in the quantification of surface-enhanced Raman scattering (SERS) enhancement factors: a renewed approach' by Arumugam Sivanesan et al., Analyst, 2015, DOI: . PMID:25453040

Sivanesan, Arumugam; Adamkiewicz, Witold; Kalaivani, Govindasamy; Kami?ska, Agnieszka; Waluk, Jacek; Ho?yst, Robert; Izake, Emad L

2014-12-15

132

[Risk factors of late ventricular arrhythmias after total correction of tetralogy of Fallot in children].  

PubMed

The authors present an analysis of pre-, intra- and postoperative risk factors of late ventricular arrhythmias in 100 children in 5-12 years after total correction of the tetralogy of Fallot. Complex arrhythmias (III-V class according to Lown classification) were found in 19% of patients. Risk factors were: in the pre- and intraoperative period--marked endocardial fibrosis of the right ventricular outflow tract, long bypass time (> 180 min) and aortic cross-clamp (> 90 min), in the post-operative period-left ventricular dysfunction in echocardiographic examination and age > 10 years at time of the study. Complex ventricular arrhythmias were more frequent in patients with associated supraventricular arrhythmias and with progressive bundle branch block. PMID:7624165

Kawalec, W; Turska-Kmie?, A; D?uzewska, J; Daszkowska, J; Grenda-Kosiec, K; Mirkowicz-Ma?ek, M; Bieganowska, K; Stodulski, J; Maruszewski, B; Burczy?ski, P

1995-01-01

133

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

SciTech Connect

Verification of commercial low enriched uranium light water reactor fuel takes place at the fuel fabrication facility as part of the overall international nuclear safeguards solution to the civilian use of nuclear technology. The fissile mass per unit length is determined nondestructively by active neutron coincidence counting using a neutron collar. A collar comprises four slabs of high density polyethylene that surround the assembly. Three of the slabs contain {sup 3}He filled proportional counters to detect time correlated fission neutrons induced by an AmLi source placed in the fourth slab. Historically, the response of a particular collar design to a particular fuel assembly type has been established by careful cross-calibration to experimental absolute calibrations. Traceability exists to sources and materials held at Los Alamos National Laboratory for over 35 years. This simple yet powerful approach has ensured consistency of application. Since the 1980's there has been a steady improvement in fuel performance. The trend has been to higher burn up. This requires the use of both higher initial enrichment and greater concentrations of burnable poisons. The original analytical relationships to correct for varying fuel composition are consequently being challenged because the experimental basis for them made use of fuels of lower enrichment and lower poison content than is in use today and is envisioned for use in the near term. Thus a reassessment of the correction factors is needed. Experimental reassessment is expensive and time consuming given the great variation between fuel assemblies in circulation. Fortunately current modeling methods enable relative response functions to be calculated with high accuracy. Hence modeling provides a more convenient and cost effective means to derive correction factors which are fit for purpose with confidence. In this work we use the Monte Carlo code MCNPX with neutron coincidence tallies to calculate the influence of Gd{sub 2}O{sub 3} burnable poison on the measurement of fresh pressurized water reactor fuel. To empirically determine the response function over the range of historical and future use we have considered enrichments up to 5 wt% {sup 235}U/{sup tot}U and Gd weight fractions of up to 10 % Gd/UO{sub 2}. Parameterized correction factors are presented.

Croft, Stephen [Los Alamos National Laboratory; Favalli, Andrea [Los Alamos National Laboratory; Swinhoe, Martyn T. [Los Alamos National Laboratory

2012-06-19

134

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

SciTech Connect

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

Iliescu, Elena; Bercea, Sorin; Dudu, Dorin; Celarel, Aurelia [National Institute of R and D for Physics and Nuclear Engineering-Horia Hulubei, Reactorului 30 St, P.O.BOX MG-6,Magurele, cod 077125 (Romania)

2013-12-16

135

Nuclear and QED corrections to the bound-electron g factor  

NASA Astrophysics Data System (ADS)

We calculate nuclear shape and quantum electrodynamic corrections to the g factor of a bound electron [1,2]. These theoretical studies are motivated by the current improvement of experimental possibilities: on the one hand, in a recent Penning trap measurement [2], the g factor of ^28Si^13+ has been determined with an unprecedented 5 .10-10 relative uncertainty. A novel experimental technique will further improve accuracy to the 10-11 level. On the other hand, experiments with ions as heavy as ^238U^91+ will be performed soon at the HITRAP-FAIR facility. For such heavy ions, nuclear effects play an important role. The leading relativistic nuclear deformation correction has been derived analytically and also its influence on one-loop quantum electrodynamic terms has been evaluated. We present results for medium- and high-Z hydrogenlike ions, which become significant already for mid-Z ions, and for very heavy elements it even reaches the 10-6 level, as we show in [1].[4pt] [1] J. Zatorski, N. S. Oreshkina, C. H. Keitel, and Z. Harman, Phys. Rev. Lett., in press; arXiv:1110.3330 [2] S. Sturm, A. Wagner, B. Schabinger, J. Zatorski, et al., Phys. Rev. Lett. 107, 023002 (2011).

Zatorski, Jacek; Oreshkina, Natalia S.; Keitel, Christoph H.; Harman, Zoltán

2012-06-01

136

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

PubMed

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

Lin, Uei-Tyng; Chu, Chien-Hau

2006-05-01

137

Break Correction of Swiss Daily and Sub-Daily Temperature Series  

NASA Astrophysics Data System (ADS)

Many applications in climate science require high-quality, long-term data at a high temporal resolution. However, such records are often affected by artificial breaks. The challenging task of homogenizing daily and sub-daily data has only been partially addressed in recent years. Therefore, the number of available datasets providing homogeneous daily and sub-daily series is still small compared to the volume of monthly or annual data. In this study, series of daily maximum (Tmax), daily minimum (Tmin), morning (Tmorn), noon (Tnoon) and evening (Teve), and daily mean (Tmean) temperatures measured in 61 stations of the Swiss climate observation network were corrected for artificial breaks. The break detection for the above mentioned series was accomplished in a former study by using a combination of three different break detection methods. Here the previously determined breakpoints are corrected by applying the method of higher-order moments for autocorrelated data (HOMAD), which is an improved version of the higher-order moments method (HOM), providing an objective choice of regression parameters.

Auchmann, Renate; Kuglitsch, Franz; Toreti, Andrea; Brönnimann, Stefan

2014-05-01

138

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

139

Temperature can interact with landscape factors to affect songbird productivity.  

PubMed

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

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

2013-04-01

140

Free oscillation rheometry monitoring of haemodilution and hypothermia and correction with fibrinogen and factor XIII concentrates  

PubMed Central

Background Haemodilution and hypothermia induce coagulopathy separately, but their combined effect on coagulation has not been widely studied. Fibrinogen concentrate can correct dilutional coagulopathy and has an additional effect when combined with factor XIII concentrate. However, their effect on dilutional coagulopathy concomitant with hypothermia has not been studied previously. Free oscillation rheometry – FOR (Reorox®) – is a novel viscoelastic haemostatic assay that has not been studied in this context before. Methods Blood from 10 healthy volunteers was diluted by 33% with hydroxyethyl starch or Ringer’s acetate solutions. Effects of fibrinogen added in vitro with and without factor XIII were studied at 33°C and 37°C. Coagulation velocity (coagulation time) and clot strength (elasticity) were assessed with FOR. Coagulation was initiated in vitro with thromboplastin alone, or thromboplastin plus a platelet inhibitor. Results Hydroxyethyl starch increased the coagulation time and decreased clot strength significantly more than Ringer’s acetate solution, both in the presence and absence of a platelet inhibitor. There was a significant interaction between haemodilution with hydroxyethyl starch and hypothermia, resulting in increased coagulation time. After addition of fibrinogen, coagulation time shortened and elasticity increased, with the exception of fibrinogen-dependent clot strength (i.e., elasticity in the presence of a platelet inhibitor) after hydroxyethyl starch haemodilution. Factor XIII had an additional effect with fibrinogen on fibrinogen-dependent clot strength in blood diluted with Ringer’s acetate solution. Hypothermia did not influence any of the coagulation factor effects. Conclusions Both haemodilution and mild hypothermia impaired coagulation. Coagulopathy was more pronounced after haemodilution with hydroxyethyl starch than with Ringer’s acetate. Addition of fibrinogen with factor XIII was unable to reverse hydroxyethyl starch induced clot instability, but improved coagulation in blood diluted with Ringer’s acetate solution. Fibrinogen improved coagulation irrespective of hypothermia. PMID:23517637

2013-01-01

141

Volume/pressure curve of total respiratory system in paralysed patients: artefacts and correction factors.  

PubMed

The volume/pressure (V/P) curve of the total respiratory system in paralysed patients is drawn assuming that volume changes of the respiratory system (delta V resp) equals volume displacement of the measuring apparatus (delta V syr), usually a supersyringe. However, in 93 VP curves we found that O2 removed from the lung-syringe system during the procedure (proportional to the time) largely exceeds the CO2 added to the lung-syringe system (delta V gas). This results in a net loss of volume from the system (delta V resp less than delta V-syr). Deflation compliance, hysteresis area and ratio are significantly affected by this phenomenon. Inflation compliance is less influenced by delta V gas, partially compensated by the intrapulmonary gas expansion due to the temperature changes. We conclude that the parameters computed on the deflation limb of V/P curve are misleading if proper correction of the volume scale is not introduced. PMID:3558932

Gattinoni, L; Mascheroni, D; Basilico, E; Foti, G; Pesenti, A; Avalli, L

1987-01-01

142

BCS Instability and Finite Temperature Corrections to Tachyon Mass in Intersecting D1-Branes  

E-print Network

A holographic description of BCS superconductivity is given in arxiv:1104.2843. This model was constructed by insertion of a pair of D8-branes on a D4-background. The spectrum of intersecting D8-branes has tachyonic modes indicating an instability which is identified with the BCS instability in superconductors. Our aim is to study the stability of the intersecting branes under finite temperature effects. Many of the technical aspects of this problem are captured by a simpler problem of two intersecting D1-branes on flat background. In the simplified set-up we compute the one-loop finite temperature corrections to the tree-level tachyon mass using the frame-work of SU(2) Yang-Mills theory in (1 + 1)-dimensions. We show that the one-loop two-point functions are ultraviolet finite due to cancellation of ultraviolet divergence between the amplitudes containing bosons and fermions in the loop. The amplitudes are found to be infrared divergent due to the presence of massless fields in the loops. We compute the fini...

Chowdhury, Sudipto Paul; Sathiapalan, B

2014-01-01

143

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

NASA Technical Reports Server (NTRS)

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

Blakenship, Clay; Zavodsky, Bradley; Blackwell, William

2014-01-01

144

Humidity and aggregate content correction factors for air-coupled ultrasonic evaluation of concrete.  

PubMed

This paper describes the use of non-contact ultrasound for the evaluation of concrete. Micromachined capacitance transducers are used to transmit ultrasonic longitudinal chirp signals through concrete samples using air as the coupling medium, and a pulse compression technique is then employed for measurement of time of flight through the sample. The effect on the ultrasonic wave speed of storing concrete samples, made with the same water/cement ratio, at different humidity levels is investigated. It is shown that there is a correlation between humidity and speed of sound, allowing a correction factor for humidity to be derived. A strong positive linear correlation between aggregate content and speed of sound was then observed; there was no obvious correlation between compressive strength and speed of sound. The results from the non-contact system are compared with that from a contact system, and conclusions drawn concerning coupling of energy into the samples. PMID:15567195

Berriman, J; Purnell, P; Hutchins, D A; Neild, A

2005-02-01

145

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

PubMed

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

Bouafassa, Amar; Rahmani, Lazhar; Mekhilef, Saad

2014-10-31

146

Temperature variation of the structure factor of liquid helium  

NASA Astrophysics Data System (ADS)

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

Isihara, A.

1981-07-01

147

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

SciTech Connect

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

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

2008-09-15

148

Replacement correction factors for plane-parallel ion chambers in electron beams  

SciTech Connect

Purpose: Plane-parallel chambers are recommended by dosimetry protocols for measurements in (especially low-energy) electron beams. In dosimetry protocols, the replacement correction factor P{sub repl} is assumed unity for ''well-guarded'' plane-parallel chambers in electron beams when the front face of the cavity is the effective point of measurement. There is experimental evidence that ion chambers which are not well-guarded (e.g., Markus) have nonunity P{sub repl} values. Monte Carlo simulations are employed in this study to investigate the replacement correction factors for plane-parallel chambers in electron beams. Methods: Using previously established Monte Carlo calculation methods, the values of P{sub repl} are calculated with high statistical precision for the cavities of a variety of plane-parallel chambers in a water phantom irradiated by various electron beams. The dependences of the values of P{sub repl} on the beam quality, phantom depth, as well as the guard ring width are studied. Results: In the dose fall-off region for low-energy beams, the P{sub repl} values are very sensitive to depth. It is found that this is mainly due to the gradient effect, which originates from the fact that the effective point of measurement for many plane-parallel chambers should not be at the front face of the cavity but rather shifted toward the center of the cavity by a fraction of a millimeter. Using the front face of the cavity as the effective point of measurement, the calculated values of P{sub repl} at d{sub ref} are not unity for some well-guarded plane-parallel chambers. The calculated P{sub repl} values for the Roos chamber are close to 1 for all electron beams. The calculation results for the Markus chamber are in good agreement with the measured values. Conclusions: The appropriate selection of the effective point of measurement for plane-parallel chambers in electron beams is an important issue. If the effective point of measurement is correctly accounted for, the P{sub repl} values would be almost independent of depth. Both the guard ring width and the ratio of the collecting volume diameter to the cavity thickness can influence the values of P{sub repl}. For a diameter to thickness ratio of 5 (e.g., NACP02 chamber), the guard width has to be 6 mm for the chamber to be considered as well-guarded, i.e., have a P{sub repl} value of 1.00.

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

2010-02-15

149

Coulomb corrections to the extraction of the density and temperature in non-relativistic heavy ion collisions  

NASA Astrophysics Data System (ADS)

We address the role of Coulomb interaction in the determination of densities and temperatures of hot sources produced in heavy ion collisions. Such quantities can be obtained from the quadrupole momentum and multiplicity fluctuations of the emitted light particles. In this paper we modify the method by taking explicitly into account Coulomb corrections. The classical and quantum limits for fermions are discussed. In the classical case we find that the temperatures determined from 3H and 3He, after the Coulomb correction, are very similar to those obtained from neutrons within the constrained molecular dynamics approach. In the quantum case, the proton temperature becomes very similar to neutron’s, while densities are not sensitive to the Coulomb corrections.

Zheng, Hua; Giuliani, Gianluca; Bonasera, Aldo

2014-05-01

150

Output correction factors for nine small field detectors in 6 MV radiation therapy photon beams: A PENELOPE Monte Carlo study  

SciTech Connect

Purpose: To determine detector-specific output correction factors,k{sub Q} {sub c{sub l{sub i{sub n}}}} {sub ,Q} {sub m{sub s{sub r}}} {sup f{sub {sup {sub c}{sub l}{sub i}{sub n}{sub {sup ,f{sub {sup {sub m}{sub s}{sub r}{sub ,}}}}}}}} in 6 MV small photon beams for air and liquid ionization chambers, silicon diodes, and diamond detectors from two manufacturers. Methods: Field output factors, defined according to the international formalism published byAlfonso et al. [Med. Phys. 35, 5179–5186 (2008)], relate the dosimetry of small photon beams to that of the machine-specific reference field; they include a correction to measured ratios of detector readings, conventionally used as output factors in broad beams. Output correction factors were calculated with the PENELOPE Monte Carlo (MC) system with a statistical uncertainty (type-A) of 0.15% or lower. The geometries of the detectors were coded using blueprints provided by the manufacturers, and phase-space files for field sizes between 0.5 × 0.5 cm{sup 2} and 10 × 10 cm{sup 2} from a Varian Clinac iX 6 MV linac used as sources. The output correction factors were determined scoring the absorbed dose within a detector and to a small water volume in the absence of the detector, both at a depth of 10 cm, for each small field and for the reference beam of 10 × 10 cm{sup 2}. Results: The Monte Carlo calculated output correction factors for the liquid ionization chamber and the diamond detector were within about ±1% of unity even for the smallest field sizes. Corrections were found to be significant for small air ionization chambers due to their cavity dimensions, as expected. The correction factors for silicon diodes varied with the detector type (shielded or unshielded), confirming the findings by other authors; different corrections for the detectors from the two manufacturers were obtained. The differences in the calculated factors for the various detectors were analyzed thoroughly and whenever possible the results were compared to published data, often calculated for different accelerators and using the EGSnrc MC system. The differences were used to estimate a type-B uncertainty for the correction factors. Together with the type-A uncertainty from the Monte Carlo calculations, an estimation of the combined standard uncertainty was made, assigned to the mean correction factors from various estimates. Conclusions: The present work provides a consistent and specific set of data for the output correction factors of a broad set of detectors in a Varian Clinac iX 6 MV accelerator and contributes to improving the understanding of the physics of small photon beams. The correction factors cannot in general be neglected for any detector and, as expected, their magnitude increases with decreasing field size. Due to the reduced number of clinical accelerator types currently available, it is suggested that detector output correction factors be given specifically for linac models and field sizes, rather than for a beam quality specifier that necessarily varies with the accelerator type and field size due to the different electron spot dimensions and photon collimation systems used by each accelerator model.

Benmakhlouf, Hamza, E-mail: hamza.benmakhlouf@karolinska.se [Department of Medical Physics, Karolinska University Hospital, SE-171 76 Stockholm, Sweden, and Department of Physics, Medical Radiation Physics, Stockholm University and Karolinska Institute, SE-171 76 Stockholm (Sweden)] [Department of Medical Physics, Karolinska University Hospital, SE-171 76 Stockholm, Sweden, and Department of Physics, Medical Radiation Physics, Stockholm University and Karolinska Institute, SE-171 76 Stockholm (Sweden); Sempau, Josep [Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, Diagonal 647, E-08028, Barcelona (Spain)] [Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, Diagonal 647, E-08028, Barcelona (Spain); Andreo, Pedro [Department of Physics, Medical Radiation Physics, Stockholm University and Karolinska Institute, SE-171 76 Stockholm (Sweden)] [Department of Physics, Medical Radiation Physics, Stockholm University and Karolinska Institute, SE-171 76 Stockholm (Sweden)

2014-04-15

151

Optimize placement of in-plant power-factor correction capacitors  

SciTech Connect

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

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

1995-10-01

152

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

153

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

PubMed

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

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

2013-09-21

154

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

PubMed

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

Hale, Alan C; Tries, Mark A

2011-02-01

155

Region of validity of the finite–temperature Thomas–Fermi model with respect to quantum and exchange corrections  

SciTech Connect

We determine the region of applicability of the finite–temperature Thomas–Fermi model and its thermal part with respect to quantum and exchange corrections. Very high accuracy of computations has been achieved by using a special approach for the solution of the boundary problem and numerical integration. We show that the thermal part of the model can be applied at lower temperatures than the full model. Also we offer simple approximations of the boundaries of validity for practical applications.

Dyachkov, Sergey, E-mail: serj.dyachkov@gmail.com [Joint Institute for High Temperatures RAS, Izhorskaya 13 bldg. 2, Moscow 125412 (Russian Federation) [Joint Institute for High Temperatures RAS, Izhorskaya 13 bldg. 2, Moscow 125412 (Russian Federation); Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region 141700 (Russian Federation); Levashov, Pavel, E-mail: pasha@ihed.ras.ru [Joint Institute for High Temperatures RAS, Izhorskaya 13 bldg. 2, Moscow 125412 (Russian Federation) [Joint Institute for High Temperatures RAS, Izhorskaya 13 bldg. 2, Moscow 125412 (Russian Federation); Tomsk State University, 36 Lenin Prospekt, Tomsk 634050 (Russian Federation)

2014-05-15

156

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

PubMed Central

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

2013-01-01

157

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

SciTech Connect

The novel power factor correction system described here 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. Work on this concept was begun in the early 1980`s by Mr. Frederick Rohatyn. The invention was granted a U.S. Patent (No. 4,672,298) in June 1987. Mr. Rohatyn continued his experiments for four year`s following issuance of the patent. During that time, he built several prototypes in order to develop a practical realization of his idea. The invention was evaluated technically by the U.S. Department of Commerce, National Institute of Standards and Technology (NIST), resulting in very favorable recommendations. In the invention, the compensating reactive power is generated by a linear capacitor. A transformer is connected in series with the capacitor. The voltage applied to the capacitor terminals can be varied from zero to a maximum level. This is done by supplying the primary winding of the series transformer from a variable auto-transformer. This feature permits continuous variation of the reactive power generated by the capacitor. Based on the results of this study, the industrial partner intends to develop a line of production models and market them to power management companies worldwide.

Zabar, Z.; Kaish, N.

1997-08-01

158

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

159

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

160

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

161

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

SciTech Connect

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

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

2013-09-01

162

Systematic uncertainties in the Monte Carlo calculation of ion chamber replacement correction factors  

SciTech Connect

In a previous study [Med. Phys. 35, 1747-1755 (2008)], the authors proposed two direct methods of calculating the replacement correction factors (P{sub repl} or p{sub cav}p{sub dis}) for ion chambers by Monte Carlo calculation. By ''direct'' we meant the stopping-power ratio evaluation is not necessary. The two methods were named as the high-density air (HDA) and low-density water (LDW) methods. Although the accuracy of these methods was briefly discussed, it turns out that the assumption made regarding the dose in an HDA slab as a function of slab thickness is not correct. This issue is reinvestigated in the current study, and the accuracy of the LDW method applied to ion chambers in a {sup 60}Co photon beam is also studied. It is found that the two direct methods are in fact not completely independent of the stopping-power ratio of the two materials involved. There is an implicit dependence of the calculated P{sub repl} values upon the stopping-power ratio evaluation through the choice of an appropriate energy cutoff {Delta}, which characterizes a cavity size in the Spencer-Attix cavity theory. Since the {Delta} value is not accurately defined in the theory, this dependence on the stopping-power ratio results in a systematic uncertainty on the calculated P{sub repl} values. For phantom materials of similar effective atomic number to air, such as water and graphite, this systematic uncertainty is at most 0.2% for most commonly used chambers for either electron or photon beams. This uncertainty level is good enough for current ion chamber dosimetry, and the merits of the two direct methods of calculating P{sub repl} values are maintained, i.e., there is no need to do a separate stopping-power ratio calculation. For high-Z materials, the inherent uncertainty would make it practically impossible to calculate reliable P{sub repl} values using the two direct methods.

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

2009-05-15

163

Correction Factor for Determining the London Penetration Depth from Strip Resonators  

NASA Technical Reports Server (NTRS)

A significant disagreement is often seen between the theoretical temperature dependent magnetic penetration depth profile and experimentally derived calculations based on stripline type resonators. This short paper shows that the disagreement can be attributed to the susceptance coupled into the resonator from the gap discontinuity as well as the feed line. When the effect is taken into account, the natural resonant frequency of the resonator is increased, and the frequency shift due to kinetic inductance can be calculated much more accurately. While it is necessary to include this effect to determine the penetration depth, it is shown that the impact on unloaded quality factor is generally negligible. The situation when the strip characteristic impedance is not matched to the generator is included.

Romanofsky, Robert R.

1995-01-01

164

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

SciTech Connect

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

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

2013-01-15

165

Method for the rapid temperature correction of a transmission in an inhomogeneous atmosphere  

NASA Technical Reports Server (NTRS)

The value of the transmission function in a heterogeneous atmosphere is determined by iterative correction of values in particular layers. The iterative equation and a set of absolute values of errors is presented in two tables.

Varnava, V. A.; Karasev, A. B.; Sapunov, V. V.; Fedichev, O. B.

1979-01-01

166

Geometrical correction factors for finite-size probe tips in microscopic four-point-probe resistivity measurements  

NASA Astrophysics Data System (ADS)

The sheet resistance of thin film structures is commonly measured using a four-point-probe setup and involves the application of geometrical correction factors depending on the sample geometry and electrode pitch. The characterization of small thin film structures in the micrometer range requires probe tip diameters and spacings that are of similar size. An experimental realization with micro-manipulators is possible as tip distances in a range of a few micrometers can be achieved. However, such a setup requires an additional correction factor accounting for the finite probe tip contact area. Neglecting such a correction leads to an underestimation of the sheet resistance when the electrode pitch is comparable to the probe contact area diameter. Based on numerical simulation results, we develop a simplified method applying a new phenomenological correction scheme which takes into account the finite contact area size for small probe distances. This method can be applied directly without any additional numerical simulations and corrects the underestimation due to the probe tip size significantly.

Ilse, Klemens; Tänzer, Tommy; Hagendorf, Christian; Turek, Marko

2014-12-01

167

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

168

Finite Volume Corrections to the SU(3) Deconfining Temperature due to a Confined Exterior  

E-print Network

Deconfined regions in relativistic heavy ion collisions are limited to small volumes surrounded by a confined exterior. Using the geometry of a double layered torus, we keep an outside temperature slightly lower than the inside temperature, so that both regions are in the SU(3) scaling region. Deconfined volume sizes are chosen to be in a range typical for such volumes created at the BNL RHIC. Even with small temperature differences a dependence of the (pseudo) deconfining temperature on a colder surrounding temperature is clearly visible. For temporal lattice sizes Ntau=4, 6 and 8 we find consistency with SU(3) scaling behavior for the measured transition temperature signals.

Bernd A. Berg; Hao Wu

2011-09-03

169

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

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

170

Analytic expressions for threshold corrections to the finite-temperature higgs potential in the minimal supersymmetric standard model  

NASA Astrophysics Data System (ADS)

Within the minimal supersymmwtric standard model (MSSM) featuring an explicit CP violation, one-loop corrections to the parameters of the effective two-doublet potential are calculated at finite temperature for various scales of the mass parameters in the sector of soft supersymmetry breaking. It is shown that the splitting of scalar-quark masses has a strong effect on the effective parameters of the potential and that, in the limiting case where all mass parameters of the squark sector are degenerate and where the temperature is zero, the potential parameters reduce to the results obtained previously.

Borisov, A. O.; Dolgopolov, M. V.; Dubinin, M. N.; Rykova, E. N.

2009-01-01

171

Quantum corrections to temperature dependent electrical conductivity of ZnO thin films degenerately doped with Si  

SciTech Connect

ZnO thin films degenerately doped with Si (Si{sub x}Zn{sub 1?x}O) in the concentrations range of ?0.5% to 5.8% were grown by sequential pulsed laser deposition on sapphire substrates at 400?°C. The temperature dependent resistivity measurements in the range from 300 to 4.2?K revealed negative temperature coefficient of resistivity (TCR) for the 0.5%, 3.8%, and 5.8% doped Si{sub x}Zn{sub 1?x}O films in the entire temperature range. On the contrary, the Si{sub x}Zn{sub 1?x}O films with Si concentrations of 1.0%, 1.7%, and 2.0% showed a transition from negative to positive TCR with increasing temperature. These observations were explained using weak localization based quantum corrections to conductivity.

Das, Amit K., E-mail: amitkrdh@gmail.com; Ajimsha, R. S.; Kukreja, L. M. [Laser Materials Processing Division, Raja Ramanna Center for Advanced Technology, Indore 452 013 (India)

2014-01-27

172

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

Microsoft Academic Search

Temperature changes affect volume measurements in several ways. The dimensions of the tank, and the density and level of the liquid it contains vary with temperature. In addition, the response signal of the sensor and hence the response of the liquid-level detection device may change with temperature. Level measurement devices can be grouped according to four measurement points of reference:

S. Suda; B. Keisch

1993-01-01

173

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

174

Development of correction factors for landfill gas emission model suiting Indian condition to predict methane emission from landfills.  

PubMed

Methane emission from landfill gas emission (LandGEM) model was validated through the results of laboratory scale biochemical methane potential assay. Results showed that LandGEM model over estimates methane (CH4) emissions; and the true CH4 potential of waste depends on the level of segregation. Based on these findings, correction factors were developed to estimate CH4 emission using LandGEM model especially where the level of segregation is negligible or does not exist. The correction factors obtained from the study were 0.94, 0.13 and 0.74 for food waste, mixed un-segregated municipal solid waste (MSW) and vegetable wastes, respectively. PMID:24685512

Sil, Avick; Kumar, Sunil; Wong, Jonathan W C

2014-09-01

175

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

176

A novel single-stage single-phase DC uninterruptible power supply with power-factor correction  

Microsoft Academic Search

Nowadays, DC uninterruptible power supply (DC-UPS) systems are becoming a reliable solution in order to improve the efficiency in switch-mode power supplies. An important challenge in the incorporation of power factor correction and fast dynamic output response is low-cost power electronic hardware. This paper describes a novel and simple DC-UPS structure, which offers excellent characteristics in terms of cost, size,

E. Rodriguez; D. Abud; J. Arau

1999-01-01

177

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

SciTech Connect

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

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

1993-05-01

178

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

E-print Network

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

Henryk Czyz; Johann H. Kuhn; Szymon Tracz

2014-11-19

179

Nucleon form factors and final state radiative corrections to e+e-?p ¯ p ?  

NASA Astrophysics Data System (ADS)

New parametrizations for the electric and the magnetic form factors of a proton and neutron are presented. The proton form factors describe well the recent measurements by the BABAR Collaboration and earlier ones of the ratio of the form factors in a spacelike region. The neutron form factors are consistent with earlier measurements of neutron pair production and ratio of the form factors in the spacelike region. These form factors are implemented into the generator phokhara, which simulates the reactions e+e-?p ¯ p ? and e+e-?n ¯ n ? . The influence of final state radiation is investigated.

Czy?, Henryk; Kühn, Johann H.; Tracz, Szymon

2014-12-01

180

Wall correction factors for calibration of plane-parallel ionization chambers with high-energy photon beams  

NASA Astrophysics Data System (ADS)

Most dosimetry protocols recommend that calibration of plane-parallel ionization chambers be performed in an electron beam of sufficiently high energy by comparison with cylindrical chambers. For various plane-parallel chambers, the 1997 IAEA TRS-381 protocol includes an overall perturbation factor pQ for electron beams, a wall correction factor pwall for a 60Co beam and the product of two wall corrections kattkm for 60Co in-air calibration. The recommended values of pwall for plane-parallel chambers, however, are limited to certain phantom materials and a 60Co beam, and are not given for other phantom materials and x-ray beams. In this work, the pwall values of the commercially available NACP, PTW/Markus and PTW/Roos plane-parallel chambers in a solid water phantom have been determined with 60Co and 4 and 10 MV photon beams. The kattkm values for the NACP and PTW/Markus chambers have also been obtained. The wall correction factors pwall and kattkm have been determined by intercomparison with a calibrated Farmer chamber. The average value of pwall for these plane-parallel chambers was 1.005±0.1% (1 SD) for 60Co beams and 1.007±0.2% (1 SD) for both 4 MV and 10 MV photons. The kattkm values for the NACP and PTW/Markus chambers were about 1.5% lower than other published data.

Araki, Fujio; Ikeda, Ryuji; Shirakawa, Yuichi; Shimonobou, Toshiaki; Moribe, Nobuyuki; Takada, Takao; Takahashi, Mutsumasa; Oura, Hiroki; Matoba, Masaru

2000-09-01

181

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

PubMed Central

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

Gelman, David; Schwartz, Steven D.

2011-01-01

182

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

183

Light and Temperature: Key Factors Affecting Walleye Abundance and Production  

Microsoft Academic Search

We used published information to determine optimum light and temperature conditions for walleye Sander vitreus (formerly Stizostedion vitreum) and then applied this simple niche definition to predict how water clarity, temperature, and bathymetry affect walleye habitat availability. Our model calculated thermal–optical habitat area (TOHA), the benthic area of a lake that supplies optimum light, and temperature conditions for walleye during

Nigel P. Lester; Alan J. Dextrase; Robert S. Kushneriuk; Michael R. Rawson; Phil A. Ryan

2004-01-01

184

Looking for simple correction functions between the mean radiant temperature from the "standard black globe" and the "six-directional" techniques in Taiwan  

NASA Astrophysics Data System (ADS)

Mean radiant temperature (T mrt) values were calculated and compared to each other in Taiwan based on the six-directional and globe techniques. In the case of the six-directional technique (measurements with pyranometers and pyrgeometers), two different T mrt values were calculated: one representing the radiation load on a standing man [T mrt(st)] and the other which refers to a spherical reference shape [T mrt(sp)]. Moreover, T mrt(T g ) was obtained through the globe thermometer technique applying the standard black globe. Comparing T mrt values based on the six-directional technique but with different reference shapes revealed that the difference was always in the +/-5 °C domain. Of the cases, 75 % fell into the +/-5 °C Delta Tmrt range when we compared different techniques with similar reference shapes [T mrt(sp) and T mrt(T g )] and only 69 % when we compared the different techniques with different reference shapes [T mrt(st) and T mrt(T g )]. Based on easily accessible factors, simple correction functions were determined to make the T mrt(T g ) values of already existing outdoor thermal comfort databases comparable with other databases which involve sixdirectional T mrt. The corrections were conducted directly between the T mrt(T g ) and T mrt(sp) values and also indirectly, i.e., by using the values of T g to reduce the differences between T mrt(sp) and T mrt(T g ). Both correction methods resulted in considerable improvement and reduced the differences between the T mrt(sp) and the T mrt(T g ) values. However, validations with an independent database from Hungary revealed that it is not suggested to apply the correction functions under totally different background climate conditions.

Kántor, Noémi; Kovács, Attila; Lin, Tzu-Ping

2014-07-01

185

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

PubMed

Dosimetry for Gamma-Knife requires detectors with high spatial resolution and minimal angular dependence of response. Angular dependence and end effect time for p-type silicon detectors (PTW Diode P and Diode E) and PTW PinPoint ionization chamber were measured with Gamma-Knife beams. Weighted angular dependence correction factors were calculated for each detector. The Gamma-Knife output factors were corrected for angular dependence and end effect time. For Gamma-Knife beams angle range of 84°-54°. Diode P shows considerable angular dependence of 9% and 8% for the 18 mm and 14, 8, 4 mm collimator, respectively. For Diode E this dependence is about 4% for all collimators. PinPoint ionization chamber shows angular dependence of less than 3% for 18, 14 and 8 mm helmet and 10% for 4 mm collimator due to volumetric averaging effect in a small photon beam. Corrected output factors for 14 mm helmet are in very good agreement (within ±0.3%) with published data and values recommended by vendor (Elekta AB, Stockholm, Sweden). For the 8 mm collimator diodes are still in good agreement with recommended values (within ±0.6%), while PinPoint gives 3% less value. For the 4 mm helmet Diodes P and E show over-response of 2.8% and 1.8%, respectively. For PinPoint chamber output factor of 4 mm collimator is 25% lower than Elekta value which is generally not consequence of angular dependence, but of volumetric averaging effect and lack of lateral electronic equilibrium. Diodes P and E represent good choice for Gamma-Knife dosimetry. PMID:25266988

Hršak, Hrvoje; Majer, Marija; Grego, Timor; Bibi?, Juraj; Heinrich, Zdravko

2014-12-01

186

Determining temperature regulating factor for apparel fabrics containing phase change material  

Microsoft Academic Search

Purpose – In order to characterize the temperature regulating ability of fabrics containing phase change material (PCM), the test instrument has been designed and built. Design\\/methodology\\/approach – To assess temperature regulating ability, temperature regulating factor (TRF) is determined. TRF is defined by Hittle as a quotient of the amplitude of the temperature variation of the hot plate and the amplitude

Wies?awa Bendkowska; Janusz Tysiak; Leszek Grabowski; Albert Blejzyk

2005-01-01

187

A high performance uninterruptible power supply system with power factor correction  

Microsoft Academic Search

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

R. Caceres; N. Vazquez; C. Aguilar; J. Alvarez; I. Barbi; J. Arau

1997-01-01

188

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

Microsoft Academic Search

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

J. D. Lewin; P. F. Smith

1996-01-01

189

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

2002-08-19

190

Experimental derivation of wall correction factors for ionization chambers used in high dose rate 192Ir source calibration.  

PubMed

At present there are no specific primary standards for 192Ir high dose rate sources used in brachytherapy. Traceability to primary standards is guaranteed through the method recommended by the AAPM that derives the air kerma calibration factor for the 192Ir gamma rays as the average of the air kerma calibration factors for x-rays and 137Cs gamma-rays or the Maréchal et al. method that uses the energy-weighted air kerma calibration factors for 250 kV x rays and 60Co gamma rays as the air kerma calibration factor for the 192Ir gamma rays. In order to use these methods, it is necessary to use the same buildup cap for all energies and the appropriate wall correction factor for each chamber. This work describes experimental work used to derive the A(W) for four different ionization chambers and different buildup cap materials for the three energies involved in the Maréchal et al. method. The A(W) for the two most common ionization chambers used in hospitals, the Farmer NE 2571 and PTW N30001 is 0.995 and 0.997, respectively, for 250 kV x rays, 0.982 and 0.985 for 192Ir gamma rays, and 0.979 and 0.991 for 60Co gamma rays, all for a PMMA build-up cap of 0.550 gm cm(-2). A comparison between the experimental values and Monte Carlo calculations shows an agreement better than 0.9%. Availability of the A(W) correction factors for all commercial chambers allows users of the in-air calibration jig, provided by the manufacturer, to alternatively use the Maréchal et al. method. Calibration laboratories may also used this method for calibration of a well-type ionization chamber with a comparable accuracy to the AAPM method. PMID:11833542

Maréchal, M H; de Almeida, C E; Ferreira, I H; Sibata, C H

2002-01-01

191

Quantification of dopamine D(2/3) receptors in rat brain using factor analysis corrected [18F]Fallypride images.  

PubMed

The goal of this work is to quantify the binding parameters of [(18)F]Fallypride in the striatal and extrastriatal regions of the rat brain using factor analysis (FA) to correct small animal PET kinetic imaging for spillover defluorination radioactivity. Eleven rats were employed for YAP-(S)PET acquisitions and metabolite studies. All kinetic parameters including B'(max) and K(d)V(R) were estimated with a three-tissue compartment seven-parameter model (3T-7k) on the basis of all the FA-corrected data from the multi-injection protocol. Binding potential (BP(ND)) was calculated with Logan's graphical analysis taking cerebellum as the reference region and using the first injection raw (BP(ND-RAW)) and FA-corrected (BP(ND-FA)) data. Three distinct factors corresponding to free+non-specific binding, specific binding and skull and gland accumulation were recovered from FA with their corresponding spatial distributions. The resulting reconstructed images without skull and gland accumulation were improved to provide a better contrast between specific and non-specific regions. Very bad fits were obtained when using time-activity curves (TACs) calculated from the raw [(18)F]Fallypride data, whereas all TACs were well fitted by the 3T-7k model after FA correction. FA-corrected data enables the cerebellar region to be used as reference for the Logan approach. The magnitude of the BP(ND-FA) values was increased from 21% to 108% across regions and the rank order of BP(ND-FA) values (Cxcorrecting kinetic data for spillover activity. Moreover, the approach presented here with [(18)F]Fallypride data can be extended to other radioligands and also to human data which can be highly distorted by radiodefluorination as shown in the literature. PMID:22659483

Millet, Philippe; Moulin-Sallanon, Marcelle; Tournier, Benjamin B; Dumas, Noé; Charnay, Yves; Ibáñez, Vicente; Ginovart, Nathalie

2012-09-01

192

Well correction factors for three-dimensional reservoir simulation with nonsquare grid blocks and anisotropic permeability  

E-print Network

factor for the smaller cell size and the smaller penetration ratios. As mentioned above, s3D factor must be a function of kz/kh, 4~ 4888 3SS 0 RADIAL OX= B DX ~ i6 DX = 32 DX ~ 64 DX - "12B r l8 is' 18 0[STANCE FROM WELL BORE. FT Flg. 22... permeability, kh Viscosity of fluid, p Total compressibility, ct Formation volume factor, B Producing rate, q Penetration ratio, hp/ht Permeability ratio, kz/kh 0. 25 1024 ft 50. 0 0. 20 50. 0 md 0. 37 cp 4. 28 E-6 psi 0. 979 RB/STB 5000. STB/D...

Kim, Dukmin

2012-06-07

193

[Indicators of exchange of bile pigments under the action of ecopathogenic factors on the organism and correction with liposomes].  

PubMed

High levels of anthropogenic impact on the environment requires a detailed study of the features of the influence of heavy metals and ionizing radiation on living organisms, and provides for the development and use of effective means of protecting the body from its negative influence. The purpose of the work was to study the characteristics of the exchange of bile pigments of rats under the action of ecopathogenic factors (ionizing radiation and cadmium) on the organism and the corrective properties of liposomes on the basis of milk phospholipids. An analysis of the chromatographic studies of bilirubin and derivatives (nonconjugated bilirubin, bilirubin sulfate, billirubin glucuronide, urobilin and stercobilin) in the whole blood, liver, jejunum contents and feces under the action on the animal organism of ecopathogenic factors (ionizing radiation and cadmium) indicate material violation of the exchange bile pigments that may be due to the destabilization of the structural and functional hot hepatocytes. Correction of the liposomal form of biologically active additive (BAA) FLP-MD is recommended; the latter is a mixture of phospholipids isolated from milk, with a mixture of unsaturated fatty acids (oleic, linoleic, linolenic) and antioxidants (alpha-tocopherol and retinol acetate). The additive components exhibit the reparative effect of the action in respect of the damaged membrane structures with simultaneous improving of cholepoietic and billiation liver function, and therefore contribute to the normalization of exchange og bile pigments in terms of action on the body ecopathogenic factors. PMID:25033562

Mel'nychuk, D O; Hryshchenko, V A; Vesel'sky?, S P

2014-01-01

194

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

E-print Network

and the desirable quality of minimal user maintenance have resulted in widespread use of this sensor as a primary, eddy covariance measurement device. Although sonic anemometers provide an excellent platform practicalities. Temperature constitutes a primary measurement because it determines the flux of sensible heat

195

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

Microsoft Academic Search

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

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

2007-01-01

196

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

Microsoft Academic Search

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

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

2007-01-01

197

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

198

Background correction for fluorescence detection in thin-layer chromatography using factor analysis and the adaptive Kalman filter  

SciTech Connect

A method is proposed that corrects for variable background signals. This technique has been applied to the analysis of polyaromatic hydrocarbons using high-performance thin-layer chromatography with fluorescence detection. The fluorescent background from thin-layer plates was found to be highly variable, and simple background subtraction yielded imprecise and inaccurate concentration estimates. The method proposed here is based on the assumption that variable background signals can be modeled by the abstract spectra obtained from factor analysis of several background spectra, and the appropriate weighting factors can then be calculated by using the adaptive Kalman filter. It was found that the best models were obtained by selecting spectra from random locations across the thin-layer plate, as opposed to spectra from a blank lane or spectra adjacent to the analyte zone. This approach gave concentration estimates with improved accuracy and precision, in most cases, when compared to simple subtraction.

Gerow, D.D.; Rutan, S.C.

1988-05-01

199

Atmospheric circulation as a factor for air temperatures in Bulgaria  

NASA Astrophysics Data System (ADS)

The research period is 1950-2012, and includes data for air temperatures in 21 Bulgarian stations. Two circulation indices, covering the same period and showing west-east or south-north directions of transport of air masses, were calculated. Statistical methods were used in the study. The results show a significant positive trend in average annual air temperatures in almost the entire territory of Bulgaria with the exception of its eastern-northeastern part. The warming occurs mainly in March, June and July, with some stations having significant positive values also in January, May and August. The zonal index reveals an insignificant increase of western transport of air masses in the cold half of the year (October-April) and strengthening of the eastern transport in the rest of the year. The meridional index shows an increase of the northern transport of air masses over the entire year and this is particularly visible in March, June, August and September. Correlation coefficients indicate that atmospheric circulation has leading role in determination of air temperatures during the period from November to April. Western transport of air masses leads to higher temperatures in spring, autumn and winter and to lower temperatures in summer. The influence of ENSO on atmospheric circulation over Bulgaria is weak, with a time lag of 2 months. El Niño is associated with increased western and northern transport of air masses, while La Niña is associated with increased eastern and southern transport of air masses over southeastern Europe.

Nojarov, Peter

2014-08-01

200

Weld pool penetration measurement using ultrasound with thermal gradient correction factors  

Microsoft Academic Search

Weld penetration is critical to final weld performance. There are many techniques for determining surface parameters of weld pools but the transient nature of the pools, high temperatures and intense electromagnetic energy make direct measurement of the penetration of weld pools difficult. In order to determine weld pool penetration ultrasonically from below the weld pool it is necessary to compensate

John Martin Anderton

1998-01-01

201

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

202

IMPACT OF ?V-VERTEX CORRECTIONS ON THE ??0? AND ??0? TRANSITION FORM FACTORS  

NASA Astrophysics Data System (ADS)

The aim of this paper is to present an effective field theory description of the conversion transition of the vector meson V into the pseudoscalar P and the lepton-pair l+l-. The normalized form factor for ? ? ?0?* transition is presented and compared to the available data and to the predictions of other models.

Raspopov, Sergii

2014-12-01

203

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

PubMed Central

The plastic scintillation detectors (PSD) have many advantages over other detectors in small field dosimetry due to its high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs will undergo a quenching effect which makes the signal level reduced significantly when the detector is close to Bragg peak where the linear energy transfer (LET) for protons is very high. This study measures the quenching correction factor (QCF) for a PSD in clinical passive-scattering proton beams and investigates the feasibility of using PSDs in depth-dose measurements in proton beams. A polystyrene based PSD (BCF-12, ?0.5mm×4mm) was used to measure the depth-dose curves in a water phantom for monoenergetic unmodulated proton beams of nominal energies 100, 180 and 250 MeV. A Markus plane-parallel ion chamber was also used to get the dose distributions for the same proton beams. From these results, the QCF as a function of depth was derived for these proton beams. Next, the LET depth distributions for these proton beams were calculated by using the MCNPX Monte Carlo code, based on the experimentally validated nozzle models for these passive-scattering proton beams. Then the relationship between the QCF and the proton LET could be derived as an empirical formula. Finally, the obtained empirical formula was applied to the PSD measurements to get the corrected depth-dose curves and they were compared to the ion chamber measurements. A linear relationship between QCF and LET, i.e. Birks' formula, was obtained for the proton beams studied. The result is in agreement with the literature. The PSD measurements after the quenching corrections agree with ion chamber measurements within 5%. PSDs are good dosimeters for proton beam measurement if the quenching effect is corrected appropriately. PMID:23128412

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

2013-01-01

204

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

NASA Astrophysics Data System (ADS)

Plastic scintillation detectors (PSDs) have many advantages over other detectors in small field dosimetry due to their high spatial resolution, excellent water equivalence and instantaneous readout. However, in proton beams, the PSDs undergo a quenching effect which makes the signal level reduced significantly when the detector is close to the Bragg peak where the linear energy transfer (LET) for protons is very high. This study measures the quenching correction factor (QCF) for a PSD in clinical passive-scattering proton beams and investigates the feasibility of using PSDs in depth-dose measurements in proton beams. A polystyrene-based PSD (BCF-12, ?0.5 mm × 4 mm) was used to measure the depth-dose curves in a water phantom for monoenergetic unmodulated proton beams of nominal energies 100, 180 and 250 MeV. A Markus plane-parallel ion chamber was also used to get the dose distributions for the same proton beams. From these results, the QCF as a function of depth was derived for these proton beams. Next, the LET depth distributions for these proton beams were calculated by using the MCNPX Monte Carlo code, based on the experimentally validated nozzle models for these passive-scattering proton beams. Then the relationship between the QCF and the proton LET could be derived as an empirical formula. Finally, the obtained empirical formula was applied to the PSD measurements to get the corrected depth-dose curves and they were compared to the ion chamber measurements. A linear relationship between the QCF and LET, i.e. Birks' formula, was obtained for the proton beams studied. The result is in agreement with the literature. The PSD measurements after the quenching corrections agree with ion chamber measurements within 5%. PSDs are good dosimeters for proton beam measurement if the quenching effect is corrected appropriately.

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

2012-12-01

205

Introduction Temperature is regarded as an `ecological master factor' for  

E-print Network

of arterial and venous blood occur with increasing water temperature in resting rainbow trout We examined not receive any oxygenated blood via a coronary circulation while salmonids have a well-developed arterial supply of oxygen to the compact layer of the ventricle. Using in situ perfused heart preparations

Farrell, Anthony P.

206

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

207

Influence of temperature and other factors on flight behavior of the cigarette beetle (Lasioderma serricorne (Fabricus))  

Microsoft Academic Search

Temperature is an important factor that can affect the monitoring of insect populations in storage facilities. Temperature may be high enough for insect growth but not high enough to initiate flying or walking to a trap. If this is the case, then an empty pheromone trap does not necessarily mean that the facility is free from insect infestation. Temperatures within

Mahsa Fardisi

2011-01-01

208

Quasi-Active Power Factor Correction Circuit for HB LED Driver  

Microsoft Academic Search

High brightness light emitting diodes (HB LEDs) are likely to be used for general lighting applications due to their high efficiency and longer life. The paper presents a quasi-active power factor corrector (PFC) for driving a string of HB LEDs. The single-stage PFC circuit has a high efficiency, and it does not increase the voltage\\/current stress on the active switch

Kening Zhou; Jian Guo Zhang; Subbaraya Yuvarajan; Da Feng Weng

2008-01-01

209

Transforming growth factor-? superfamily ligand trap ACE-536 corrects anemia by promoting late-stage erythropoiesis.  

PubMed

Erythropoietin (EPO) stimulates proliferation of early-stage erythrocyte precursors and is widely used for the treatment of chronic anemia. However, several types of EPO-resistant anemia are characterized by defects in late-stage erythropoiesis, which is EPO independent. Here we investigated regulation of erythropoiesis using a ligand-trapping fusion protein (ACE-536) containing the extracellular domain of human activin receptor type IIB (ActRIIB) modified to reduce activin binding. ACE-536, or its mouse version RAP-536, produced rapid and robust increases in erythrocyte numbers in multiple species under basal conditions and reduced or prevented anemia in murine models. Unlike EPO, RAP-536 promoted maturation of late-stage erythroid precursors in vivo. Cotreatment with ACE-536 and EPO produced a synergistic erythropoietic response. ACE-536 bound growth differentiation factor-11 (GDF11) and potently inhibited GDF11-mediated Smad2/3 signaling. GDF11 inhibited erythroid maturation in mice in vivo and ex vivo. Expression of GDF11 and ActRIIB in erythroid precursors decreased progressively with maturation, suggesting an inhibitory role for GDF11 in late-stage erythroid differentiation. RAP-536 treatment also reduced Smad2/3 activation, anemia, erythroid hyperplasia and ineffective erythropoiesis in a mouse model of myelodysplastic syndromes (MDS). These findings implicate transforming growth factor-? (TGF-?) superfamily signaling in erythroid maturation and identify ACE-536 as a new potential treatment for anemia, including that caused by ineffective erythropoiesis. PMID:24658078

Suragani, Rajasekhar N V S; Cadena, Samuel M; Cawley, Sharon M; Sako, Dianne; Mitchell, Dianne; Li, Robert; Davies, Monique V; Alexander, Mark J; Devine, Matthew; Loveday, Kenneth S; Underwood, Kathryn W; Grinberg, Asya V; Quisel, John D; Chopra, Rajesh; Pearsall, R Scott; Seehra, Jasbir; Kumar, Ravindra

2014-04-01

210

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

211

Determination of a correction factor for the interaction potential of He + ions backscattered from a Cu(1 0 0) surface  

NASA Astrophysics Data System (ADS)

We have used coaxial impact collision ion scattering spectroscopy (CAICISS) data collected from 3 keV He + ions backscattered from a Cu(1 0 0) surface in different azimuthal orientations to investigate the influence of the screening length on CAICISS polar angle scans. We have compared the experimental data to computer simulations generated with the FAN code and found that for our experimental conditions an exceptionally low value of 0.53 was required for the correction factor to the Firsov screening length used with the Thomas-Fermi-Moliere potential. In addition we found that the Ziegler-Biersack-Littmark potential is not applicable, resulting in incorrect peak positions in the CAICISS polar angle plots.

Draxler, M.; Walker, M.; McConville, C. F.

2006-08-01

212

Constraints on the annihilation corrections in $B_{u,d}$ ${\\to}$ $PV$ decays within QCD factorization  

E-print Network

In this paper, we investigate the contributions of hard spectator scattering and annihilation in $B$ ${\\to}$ $PV$ decays within QCD factorization framework. With available experimental data on $B$ ${\\to}$ ${\\pi}K^{\\ast}$, ${\\rho}K$, ${\\pi}{\\rho}$ and $K{\\phi}$ decays, comprehensive $\\chi^2$ analyses on parameters $X_{A,H}^{i,f}$ or (${\\rho}_{A,H}^{i,f}$, ${\\phi}_{A,H}^{i,f}$) are performed, where $X_{A}^{f}$ ($X_{A}^{i}$) and $X_{H}$ are used to parameterize the endpoint divergences of the (non)factorizable annihilation and hard spectator scattering amplitudes, respectively. From $\\chi^2$ analyses, it is found that (1) the topology-dependent parameterization is feasible for $B$ ${\\to}$ $PV$ decays; (2) A relatively small value of inverse moment parameter ${\\lambda}_{B}$ ${\\sim}$ 0.2 GeV for $B$ meson wave function is allowed by $B$ ${\\to}$ $PP$, $PV$ decays; (3) At present accurate level of experimental measurements and theoretical evaluations, $X_{H}$ $=$ $X_{A}^{i}$ is a good simplification, but $X_{H}$ $\

Junfeng Sun; Qin Chang; Xiaohui Hu; Yueling Yang

2014-12-07

213

Combination of recombinant factor VIIa and fibrinogen corrects clot formation in primary immune thrombocytopenia at very low platelet counts.  

PubMed

Haemostatic treatment modalities alternative to platelet transfusion are desirable to control serious acute bleeds in primary immune thrombocytopenia (ITP). This study challenged the hypothesis that recombinant activated factor VII (rFVIIa) combined with fibrinogen concentrate may correct whole blood (WB) clot formation in ITP. Blood from ITP patients (n = 12) was drawn into tubes containing 3·2% citrate and corn trypsin inhibitor 18·3 ?g/ml. WB [mean platelet count 22 × 10(9) /l (range 0-42)] was spiked in vitro with buffer, donor platelets (+40 × 10(9) /l), rFVIIa (1 or 4 ?g/ml), fibrinogen (1 or 3 mg/ml), or combinations of rFVIIa and fibrinogen. Coagulation profiles were recorded by tissue factor (0·03 pmol/l) activated thromboelastometry. Coagulation in ITP was characterized by a prolonged clotting time (CT, 1490 s (mean)) and a low maximum velocity (MaxVel, 3·4 mm × 100/s) and maximum clot firmness (MCF, 38·2 mm). Fibrinogen showed no haemostatic effect, whereas rFVIIa reduced the CT and increased the MaxVel. The combination of fibrinogen and rFVIIa revealed a significant synergistic effect, improving all parameters (CT 794 s, MaxVel 7·9 mm × 100/s, MCF 50·7 mm) even at very low platelet counts. These data suggest that rFVIIa combined with fibrinogen corrects the coagulopathy of ITP even at very low platelet counts, and may represent an alternative to platelet transfusion. PMID:23151086

Larsen, Ole H; Stentoft, Jesper; Radia, Deepti; Ingerslev, Jørgen; Sørensen, Benny

2013-01-01

214

Quality factor temperature dependence of a surface phonon polariton resonance cavity  

NASA Astrophysics Data System (ADS)

We consider the surface phonon polariton coupling in an SiO2 optical cavity with 250 nm metal (gold (Au)/chrome (Cr)) side walls, and find a temperature dependence of the quality factor, Q =?o/??. By using optical cavities of varying widths between parallel metal walls and FTIR-ATR measurements, we first observe that the quality factor obeys an inverse power law dependence on the width. And by relating the widths to the optical path length, and ultimately to the temperature using the general thermo-optical coefficient, we show the quality factor temperature dependence. We argue that the temperature dependence of the quality factor is a practical and almost universal result that describes the energy dissipative behavior of both mechanically and optically responsive systems.

Hammonds, James S.; Stancil, Kimani A.; Stokes, Charlezetta E.

2014-09-01

215

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

PubMed

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

Matuszewski, Szymon; M?dra, Anna

2015-02-01

216

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

217

Factors Affecting the Application of a Simple Ratio Technique for Spectral Correction of a Neutron Personnel Albedo Dosimeter.  

NASA Astrophysics Data System (ADS)

To accurately assess the dose equivalent indicated by the albedo response of a neutron personnel dosimeter, additional knowledge is generally required in order to apply the needed spectral specific correction factors. This work was designed to evaluate the capability of the USAF Personnel Neutron Dosimeter to "self-calibrate" for moderated fission neutron spectra. The boron/bare ratio technique is compared with a simple theoretical model of the dosimeter and with the 23 cm (9 in) to 7.6 cm (3 in) Hankins' remmeter calibration technique. The overall goal was to provide dose-equivalent estimates comparable to those provided by the remmeter technique without the necessity of special on-site measurements. Although the boron/bare technique with the present dosimeter design fails to provide calibration factors needed for moderated fission neutron spectra, theoretical predictions based upon the model and the measured dosimeter responses are used to propose a dosimeter design which might fulfill the desired goal. Ancillary data gathered during the study are also presented.

Nelson, Robert Clifton

218

Factors contributing to the temperature beneath plaster or fiberglass cast material  

Microsoft Academic Search

BACKGROUND: Most cast materials mature and harden via an exothermic reaction. Although rare, thermal injuries secondary to casting can occur. The purpose of this study was to evaluate factors that contribute to the elevated temperature beneath a cast and, more specifically, evaluate the differences of modern casting materials including fiberglass and prefabricated splints. METHODS: The temperature beneath various types (plaster,

Michael J Hutchinson

2008-01-01

219

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 and…

Akbas, Yavuz

2012-01-01

220

Error Correction of Daily Temperature and Precipitation from Regional Climate Simulations in Europe and the Effects on Climate Change Signals  

NASA Astrophysics Data System (ADS)

State-of-the-art regional climate models (RCMs) have shown their capability to reproduce mesoscale and even finer climate variability satisfactorily. However, considerable differences between model results and observational data remain, due to scale discrepancies and model errors. This limits the direct utilization of RCM results in climate change impact studies. Besides continuous climate model improvement, empirical-statistical post-processing approaches (model output statistics) offer an immediate pathway to mitigate these model problems and to provide better input data for climate change impact assessments. Among various statistical approaches, quantile mapping (QM) represents one powerful non-parametric technique to post-process RCM outputs. In this study, results from a transient regional climate simulation (period: 1951 to 2050; general circulation model: HadCM3; emission scenario: A1B; RCM: CLM) with horizontal grid spacing of 25 km is error corrected for entire Europe based on the E-OBS European daily gridded observational dataset (http://ensembles-eu.org). Firstly, the performance of QM for correcting daily temperature and precipitation for long-term simulations is evaluated in a decadal cross-validation framework between 1961 and 2000 and the error characteristics are discussed. In the case of precipitation amount a frequency adaptation tool is presented which deals with rare situations where the probability for non-precipitation days is lower in the observations than in the model. Secondly, the issue of generating new extremes in future scenarios is raised. For this purpose, the ERA-40 reanalysis driven hindcast is used to assure best possible temporal correlation between observations and model output. The hindcast is split such that the independent validation period contains observed extremes outside the range of the calibration period. Two extrapolation schemes at the tails of the calibrated correction functions are tested and compared to the simple mapping on the calibration extremes. Finally, the impact of QM on the climate change signal (2021-2050 minus 1971-2000 from the transient simulation) is analyzed for monthly means as well as monthly extreme parameters according to spatial patterns as well as annual cycles of the climate change signals. It is demonstrated that QM reduces RCM errors by one order of magnitude independent of region or season considered. Additionally, it is shown that, if new extremes outside the calibration range occur, QM using an extrapolation of the error correction function shows more reliable results concerning extremes than using a simple mapping to the extremes of the historical calibration period. Regarding the impacts of QM on the climate change signal, it can be concluded that if variables feature a distinct trend in combination with intensity-dependent error characteristics, QM can change the mean climate change signal by more than 50% as well as the respective annual cycles. The ENSEMBLES data used in this work was funded by the EU FP6 Integrated Project ENSEMBLES (Contract number 505539) whose support is gratefully acknowledged.

Themessl, M. J.; Gobiet, A.; Heinrich, G.; Regional; Local Climate Modeling; Analysis Research Group

2010-12-01

221

Optimizing Power Factor Correction  

E-print Network

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

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

222

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

223

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

224

Correction factors kE and kQ for LiF-TLDs for dosimetry in megavoltage electron and photon beams.  

PubMed

For the determination of absorbed dose to water D,using thermolumeniscence (TL) probes in a beam different from that used for calibration, correction factors for radiation type and radiation quality kE and kQ are needed. Values for kE and kQ for two different shapes of LiF probes (rods and disks) were obtained for high-energy photon and electron beams. The relation between the absorbed dose to the medium (water) D, measured by ion-chambers according to DIN 6800-2, 2008 and TL-probes having a (60)Co-calibration factor, leads for each shape and each batch of LiF probes to correction factors for radiation type and radiation quality kE and kQ.. The influence of the shape on the correction factor of the probes amounts in our experiment up to 2%. Therefore, it is recommended that the correction factors kE and kQ for rods and disks should be checked for each batch of LiF-detectors. PMID:24973310

Bruggmoser, Gregor; Saum, Rainer; Saum, Felicitas; Gainey, Mark; Pychlau, Christian; Kapsch, Ralf-Peter; Zink, Klemens

2014-06-24

225

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. PMID:10747065

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

2000-01-01

226

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

PubMed

Environmental factors were evaluated to determine potential limitations in using cattle eye temperatures obtained through infrared thermography (IRT) for early disease detection systems or in animal welfare research studies. The effects of the following factors on IRT eye temperatures in cattle and a fabricated surrogate "eye" were evaluated: camera to object distance, wind speed, camera settings (distance, emissivity, and humidity), and solar loading. Wind speed in both live animals and using a surrogate "eye" was found to decrease the IRT temperature. In the presence of ? 7 km/h wind, the mean IRT eye temperature decreased by 0.43 ± 0.13 °C and; at higher wind speeds (? 12 km/h), the temperature decreased by 0.78 ± 0.33 °C. Direct sunlight was found to increase the IRT eye temperature by 0.56 ± 0.36 °C. It was determined that environmental factors impact IRT temperature measurements significantly and therefore must be managed to ensure reproducible and accurate readings. PMID:24290729

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

2014-02-01

227

Temperature and donor concentration dependence of the conduction electron Lande g-factor in silicon  

NASA Astrophysics Data System (ADS)

Temperature and donor concentration dependence of the conduction electron g-factor in silicon has been investigated both experimentally and theoretically. We performed electron spin resonance experiments on Si samples doped with different densities of phosphorus and lithium. Theoretical consideration is based on the renormalization of the electron energy in a weak magnetic field by the interaction with possible perturbing agents, such as phonons and impurity centers. In the second-order perturbation theory interaction of the electron subsystem with the lattice vibrations as well as ionized donors results in decreasing the conduction electron g-factor, which becomes almost linear function both of temperature and impurity concentration.

Konakov, Anton A.; Ezhevskii, Alexander A.; Soukhorukov, Andrey V.; Guseinov, Davud V.; Popkov, Sergey A.; Burdov, Vladimir A.

2013-12-01

228

Monte Carlo calculations of beam quality correction factors kQ for electron dosimetry with a parallel-plate Roos chamber  

NASA Astrophysics Data System (ADS)

Current dosimetry protocols (AAPM, IAEA, DIN) recommend the use of parallel-plate ionization chambers for the measurement of absorbed dose-to-water in clinical electron beams. For well-guarded plane-parallel chambers, it is assumed that the perturbation correction pQ is unity for all electron energies. In this study, we present detailed Monte Carlo simulations with the EGSnrc code for the widely used Roos parallel-plate chamber which is, besides other plane-parallel chamber types, recommended in all protocols. We have calculated the perturbation corrections pcav and pwall for a wide range of electron energies and for 60Co. While our results confirm the recommended value of unity for the cavity perturbation pcav, the wall-correction factor pwall depends on electron energy and decreases with increasing electron energy. For the lowest electron energies in this study (R50 ? 2 cm), pwall deviates from unity by up to 1.5%. Using the perturbation factors for the different electron energies and those for the reference beam quality, 60Co, we have calculated the beam quality correction factor kQ. For electron energies E0 > 9 MeV (R50 > 4 cm), the calculated values are in good agreement with the data published in the IAEA protocol. Deviations in the range of 0.5-0.8% are found for R50 < 3 cm.

Zink, K.; Wulff, J.

2008-03-01

229

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...

230

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...

231

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

232

Relations of Tualatin River water temperatures to natural and human-caused factors  

USGS Publications Warehouse

Aquatic research has long shown that the survival of cold-water fish, such as salmon and trout, decreases markedly as water temperatures increase above a critical threshold, particularly during sensitive life stages of the fish. In an effort to improve the overall health of aquatic ecosystems, the State of Oregon in 1996 adopted a maximum water-temperature standard of 17.8 degrees Celsius (68 degrees Fahrenheit), based on a 7-day moving average of daily maximum temperatures, for most water bodies in the State. Anthropogenic activities are not permitted to raise the temperature of a water body above this level. In the Tualatin River, a tributary of the Willamette River located in northwestern Oregon, water temperatures periodically surpass this threshold during the low-flow summer and fall months.An investigation by the U.S. Geological Survey quantified existing seasonal, diel, and spatial patterns of water temperatures in the main stem of the river, assessed the relation of water temperatures to natural climatic conditions and anthropogenic factors (such as wastewater-treatment-plant effluent and modification of riparian shading), and assessed the impact of various flow management practices on stream temperatures. Half-hourly temperature measurements were recorded at 13 monitoring sites from river mile (RM) 63.9 to RM 3.4 from May to November of 1994. Four synoptic water- temperature surveys also were conducted in the upstream and downstream vicinities of two wastewater-treatment-plant outfalls. Temperature and streamflow time-series data were used to calibrate two dynamic-flow heat-transfer models, DAFLOW-BLTM (RM 63.9-38.4) and CE-QUAL-W2 (RM 38.4-3.4).Simulations from the models provided a basis for approximating 'natural' historical temperature patterns, performing effluent and riparian-shading sensitivity analyses, and evaluating mitigation management scenarios under 1994 climatic conditions. Findings from the investigation included (1) under 'natural' conditions the temperature of the river would exceed the State standard of 17.8 degrees Celsius at many locations during the low-flow season, (2) current operation of wastewater-treatment plants increases the temperature of the river downstream of the plants under low-flow conditions, (3) river temperature is significantly affected by riparian shade variations along both the tributaries and the main stem, (4)flow releases during the low-flow season from the Henry Hagg Lake reservoir decrease the river temperature in the upper section, and (5) removal of a low diversion dam at RM 3.4 would slightly decrease temperatures below RM 10.0.

Risley, John C.

1997-01-01

233

Proteomic comparison of Ralstonia solanacearum strains reveals temperature dependent virulence factors  

PubMed Central

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

2014-01-01

234

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

SciTech Connect

This report is a part of the Hanford Environmental Dose Reconstruction (HEDR) Project, whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. The key radionuclide emitted that would affect the radiation dose was iodine-131 (Napier 1992). Because the early methods of measuring iodine-131 were not comparable to later techniques, conversion and correction factors are needed to convert the historical measurement data into concentration values that would be determined using today`s knowledge and technologies. This report describes the conversion and correction factors developed for reconstructing historical measurements of iodine-131 in Hanford-area vegetation, which was collected from 1948 through the end of December 1951.

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

1993-09-01

235

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

Microsoft Academic Search

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

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

2007-01-01

236

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

237

AC-DC Power-Factor-Corrected Switching Converter Based on Air-Gap Transformer and Pulse Position Modulator for Lighting Applications  

Microsoft Academic Search

In this paper an AC-DC power-factor-corrected switching converter based on pulse position modulator (PPM) is realized and applied to drive LED array. The PPM is realized using a Timer, which consists of a comparator and one RS flip-flop. The Timer is connected as an oscillator of lowfrequency around 5 kHz. The pulse position varies with the input rectified-voltage as modulating

Roberto Baca; Gabriel Romero Paredes; Ramon Pena

2011-01-01

238

A single-stage power factor correction AC\\/DC converter based on zero voltage switching full bridge topology with two series-connected transformers  

Microsoft Academic Search

A single-stage power factor correction ac\\/dc converter based on zero voltage switching (ZVS) full bridge topology with two series-connected transformers is proposed in this paper. The proposed converter offers a very wide ZVS range due to the configuration of two series-connected transformers. It features a high efficiency over wide load ranges. Furthermore, it shows the low voltage stress on a

Tae-Sung Kim; Gwan-Bon Koo; Gun-Woo Moon; Myung-Joong Youn

2006-01-01

239

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

SciTech Connect

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

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

1993-05-01

240

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

NASA Astrophysics Data System (ADS)

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

?ahiner, Eren; Meriç, Niyazi

2014-03-01

241

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

PubMed

A Rayleigh-Mie-scattering lidar system at an eye-safe 355-nm ultraviolet wavelength that is based on a high-spectral-resolution lidar technique is demonstrated for measuring the vertical temperature profile of the troposphere. Two Rayleigh signals, which determine the atmospheric temperature, are filtered with two Fabry-Perot etalon filters. The filters are located on the same side of the wings of the Rayleigh-scattering spectrum and are optically constructed with a dual-pass optical layout. This configuration achieves a high rejection rate for Mie scattering and reasonable transmission for Rayleigh scattering. The Mie signal is detected with a third Fabry-Perot etalon filter, which is centered at the laser frequency. The filter parameters were optimized by numerical calculation; the results showed a Mie rejection of approximately -45 dB, and Rayleigh transmittance greater than 1% could be achieved for the two Rayleigh channels. A Mie correction method is demonstrated that uses an independent measure of the aerosol scattering to correct the temperature measurements that have been influenced by the aerosols and clouds. Simulations and preliminary experiments have demonstrated that the performance of the dual-pass etalon and Mie correction method is highly effective in practical applications. Simulation results have shown that the temperature errors that are due to noise are less than 1 K up to a height of 4 km for daytime measurement for 300 W m(-2) sr(-1) microm(-1) sky brightness with a lidar system that uses 200 mJ of laser energy, a 3.5-min integration time, and a 25-cm telescope. PMID:15765711

Hua, Dengxin; Uchida, Masaru; Kobayashi, Takao

2005-03-01

242

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

243

Comparison of correction methods of inhomogeneities in daily data on example of Central European temperature and precipitation series  

NASA Astrophysics Data System (ADS)

Prior any data analysis, data quality control and homogenization have to be undertaken to get rid of erroneous values in time series. In this work we focused especially on comparison of methods for daily data inhomogeneities correction. Two basic approaches for inhomogeneity adjustments were adopted and compared: (i) "delta" method - adjustment of monthly series and projection of estimated smoothed monthly adjustments into annual variation of daily adjustments and (ii) "variable" correction of daily values according to the corresponding percentiles. "Variable" correction methods were investigated more deeply and their results were mutually compared. The methods used were HOM of Paul Della-Marta, SPLIDHOM of Olivier Mestre and a new method of Petr Stepanek. For the calculation, the software ProClimDB has been combined with R software scripts containing HOM and SPLIDHOM and the different methodological approaches were applied to daily data of various meteorological elements measured in the area of the Czech Republic. The tool is open and freely available. Series were processed by means of the developed ProClimDB and AnClim software (www.climahom.eu).

Stepanek, P.; Gruber, Ch.; Zahradnicek, P.

2009-04-01

244

Curie temperatures and modified de Gennes factors of rare earth nitrides  

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

245

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

NASA Astrophysics Data System (ADS)

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

Zhang, Wei; Webb, David J.

2014-05-01

246

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

NASA Astrophysics Data System (ADS)

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

Arnon, Ali; Selker, John; Lensky, Nadav

2014-06-01

247

An optimal and flexible control strategy for active filtering and power factor correction under non-sinusoidal line voltages  

Microsoft Academic Search

This paper gives a new insight into the concept of load compensation under distorted voltages. Achieving both unity power factor (UPF) and perfect compensation of current harmonics are not possible where competition will arise between these two important factors. Through evaluating the present control strategies, a generalized, optimal, and flexible control strategy (OFC) for harmonic compensation of utility lines is

S. Mohammad-Reza Rafiei; Hamid A. Toliyat; Reza Ghazi; Tilak Gopalarathnam

2001-01-01

248

GROWTH FACTORS DECREASE IN SUBJECTS WITH MILD TO MODERATE ALZHEIMER'S DISEASE (AD): POTENTIAL CORRECTION WITH DEHYDROEPIANDROSTERONE-SULPHATE (DHEAS)  

Microsoft Academic Search

The integrity of neuroprotection is an important component against the development of cognitive disorders and AD. Within this context, DHEAS would seem to have some positive metabolic and endocrine effects to delay brain aging by recovering the impairment of neuroprotective growth factors. In the present study we measured by ELISA the secretion of insulin-like growth factor-1 (IGF-1), vascular endothelial growth

C. Luppi; M. Fioravanti; B. Bertolini; M. Inguscio; A. Grugnetti; F. Guerriero; C. Rovelli; F. Cantoni; P. Guagnano; E. Marazzi; E. Rolfo; D. Ghianda; D. Levante; C. Guerrini; R. Bonacasa; S. B. Solerte

2009-01-01

249

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

250

[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

251

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...

252

Extremely high Q-factor mechanical modes in quartz bulk acoustic wave resonators at millikelvin temperature  

NASA Astrophysics Data System (ADS)

We demonstrate that Bulk Acoustic Wave (BAW) quartz resonator cooled down to millikelvin temperatures are excellent building blocks for hybrid quantum systems with extremely long coherence times. Two overtones of the longitudinal mode at frequencies of 15.6 and 65.4 MHz demonstrate a maximum f.Q product of 7.8×1016 Hz. With this result, the Q-factor in such devices near the quantum ground state can be four orders of magnitude better than previously attained in other mechanical systems. Tested quartz resonators possess the ultra low acoustic losses crucial for electromagnetic cooling to the phonon ground state.

Goryachev, M.; Creedon, D. L.; Ivanov, E. N.; Galliou, S.; Bourquin, R.; Tobar, M. E.

2014-12-01

253

Neonatal helper-dependent adenoviral vector gene therapy mediates correction of hemophilia A and tolerance to human factor VIII.  

PubMed

Neonatal gene therapy is a promising strategy for treating a number of congenital diseases diagnosed shortly after birth as expression of therapeutic proteins during postnatal life may limit the pathologic consequences and result in a potential "cure." Hemophilia A is often complicated by the development of antibodies to recombinant protein resulting in treatment failure. Neonatal administration of vectors may avoid inhibitory antibody formation to factor VIII (FVIII) by taking advantage of immune immaturity. A helper-dependent adenoviral vector expressing human factor VIII was administered i.v. to neonatal hemophilia A knockout mice. Three days later, mice produced high levels of FVIII. Levels declined rapidly with animal growth to 5 wk of age with stable factor VIII expression thereafter to >1 y of age. Decline in factor VIII expression was not related to cell-mediated or humoral responses with lack of development of antibodies to capsid or human factor VIII proteins. Subsequent readministration and augmentation of expression was possible as operational tolerance was established to factor VIII without development of inhibitors; however, protective immunity to adenovirus remained. PMID:21245323

Hu, Chuhong; Cela, Racel G; Suzuki, Masataka; Lee, Brendan; Lipshutz, Gerald S

2011-02-01

254

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

SciTech Connect

The boundary conditions for thermal modeling of fenestration systems assume an adiabatic condition between the fenestration system installed and the opaque envelope system. This theoretical adiabatic boundary condition may not be appropriate owing to heat transfer at the interfaces, particularly for aluminum- framed windows affixed to metal- framed walls. In such scenarios, the heat transfer at the interface may increase the discrepancy between real world thermal indices and laboratory measured or calculated indices based on NFRC Rating System.This paper discusses the development of window-wall Interface Correction Factors (ICF) to improve energy impacts of building envelope systems

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

2012-01-01

255

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

256

State-of-the-art, single-phase, active power-factor-correction techniques for high-power applications - an overview  

Microsoft Academic Search

A review of high-performance, state-of-the-art, active power-factor-correction (PFC) techniques for high-power, single-phase applications is presented. The merits and limitations of several PFC techniques that are used in today's network-server and telecom power supplies to maximize their conversion efficiencies are discussed. These techniques include various zero-voltage-switching and zero-current-switching, active-snubber approaches employed to reduce reverse-recovery-related switching losses, as well as techniques for

Milan M. Jovanovic; Yungtaek Jang

2005-01-01

257

Remote temperature inversion sensor. [For correcting aerial survey measurements for uranium; using spectral radiance measurements in 15. mu. CO band  

Microsoft Academic Search

In conducting aircraft surveys for uranium, it is found that temperature inversions can give spurious results because they promote accumulation of radon gas in the atmosphere. The ²¹Bi (daughter product of radon) gamma-rays detected from the atmosphere-borne radon are difficult to separate from the ²¹Bi gamma-rays originating from the ground, and providing a signature for uranium deposits. The purpose of

W. Malkmus; M. Griggs

1977-01-01

258

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

PubMed

This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank. PMID:25050049

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

2014-07-01

259

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

PubMed Central

This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank. PMID:25050049

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

2014-01-01

260

Correcting human heart 31P NMR spectra for partial saturation. Evidence that saturation factors for PCr/ATP are homogeneous in normal and disease states  

NASA Astrophysics Data System (ADS)

Heart PCr/ATP ratios measured from spatially localized 31P NMR spectra can be corrected for partial saturation effects using saturation factors derived from unlocalized chest surface-coil spectra acquired at the heart rate and approximate Ernst angle for phosphor creatine (PCr) and again under fully relaxed conditions during each 31P exam. To validate this approach in studies of normal and disease states where the possibility of heterogeneity in metabolite T1 values between both chest muscle and heart and normal and disease states exists, the properties of saturation factors for metabolite ratios were investigated theoretically under conditions applicable in typical cardiac spectroscopy exams and empirically using data from 82 cardiac 31P exams in six study groups comprising normal controls ( n = 19) and patients with dilated ( n = 20) and hypertrophic ( n = 5) cardiomyopathy, coronary artery disease ( n = 16), heart transplants ( n = 19), and valvular heart disease ( n = 3). When TR ? T1,(PCr), with T1(PCr) ? T1(ATP), the saturation factor for PCr/ATP lies in the range 1.5 ± 0.5, regardless of the T1 values. The precise value depends on the ratio of metabolite T1 values rather than their absolute values and is insensitive to modest changes in TR. Published data suggest that the metabolite T1 ratio is the same in heart and muscle. Our empirical data reveal that the saturation factors do not vary significantly with disease state, nor with the relative fractions of muscle and heart contributing to the chest surface-coil spectra. Also, the corrected myocardial PCr/ATP ratios in each normal or disease state bear no correlation with the corresponding saturation factors nor the fraction of muscle in the unlocalized chest spectra. However, application of the saturation correction (mean value, 1.36 ± 0.03 SE) significantly reduced scatter in myocardial PCr/ATP data by 14 ± 11% (SD) ( p ? 0.05). The findings suggest that the relative T1 values of PCr and ATP are substantially the same in chest and heart muscle and are unchanged in these disease states. The mean value for T1 (PCr)/ T1(ATP) is 2.16 ± 0.29 SE.

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

261

Unity input displacement factor correction principle for direct AC to AC matrix converters based on modulation strategy  

Microsoft Academic Search

Modulation strategies for a matrix structured direct AC to AC converter are developed. In principle, for a given set of input three-phase voltages, any desired set of output voltages can be synthesized by suitable toggling matrix switches. Mathematical proof that the direct AC to AC matrix converter can operate with unity displacement factor is provided by analyses based on the

M. Milanovic; Bojan Dobaj

2000-01-01

262

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

PubMed Central

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

Green, Barry G.; Nachtigal, Danielle

2012-01-01

263

Growth factors decrease in subjects with mild to moderate Alzheimer's disease (AD): potential correction with dehydroepiandrosterone-sulphate (DHEAS).  

PubMed

The integrity of neuroprotection is an important component against the development of cognitive disorders and AD. Within this context, DHEAS would seem to have some positive metabolic and endocrine effects to delay brain aging by recovering the impairment of neuroprotective growth factors. In the present study we measured by ELISA the secretion of insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), and transforming growth factor-beta1 (TGFbeta1) in the supernatants of cultured circulating peripheral blood mononuclear cells (PBMC) from which natural killer cells (NK) were separated (PBMC-NK) (pg/ml/7.75x10(6) cells) in healthy subjects and in age-matched patients with mild to moderate AD. The growth factors were measured in spontaneous conditions and after stimulation with growth hormone (GH) 1 microg/ml (IGF-1), lipopolysaccharide (LPS) 1 microg/ml (VEGF) and glucose 10 microM (TGF(beta1). AD group demonstrated at baseline a severe reduction of IGF-1 (3.7+1.2 pg/ml after GH), VEGF (63+/-18 pg/ml spontaneous and 210+/-65 pg/ml after LPS) and TGF(beta1 (33+/-10 pg/ml spontaneous and 75+/-12 pg/ml after glucose) secretions compared to healthy elderly subjects (IGF-1, 9.5+/-2.8 pg/ml after GH, p<0.001; VEGF, 117+/-38 pg/ml spontaneous, p<0.001 and 690+/-120 pg/ml after LPS, p<0.001; and TGF(beta1, 73+/-21 pg/ml spontaneous, p<0.001 and 169+/-53 pg/ml after glucose, p<0.001). Significant positive correlations between IGF-1 and VEGF concentrations were found both in healthy subjects (r=0.87, p<0.001) and in AD subjects (r=0.87, p<0.001). The co-incubation of NK cells with DHEAS (10(6) M/ml/cells) significantly increase IGF-1, VEGF and TGF (beta1 production, reaching in AD group the normal concentrations found in healthy subjects (IGF-1, 7.9 + 2.4 pg/ml after GH; VEGF, 105+/-31 pg/ml spontaneous and 670+/-112 pg/ml after LPS; and TGFfbeta1, 68+/-18 pg/ml spontaneous and 155+/-48 pg/ml after glucose). These data suggested that DHEAS is able to increase the immunoendocrine production of neuroprotective growth factors, which is reduced in AD subjects, so suggesting a new approach in the treatment of dementia. PMID:19836631

Luppi, C; Fioravanti, M; Bertolini, B; Inguscio, M; Grugnetti, A; Guerriero, F; Rovelli, C; Cantoni, F; Guagnano, P; Marazzi, E; Rolfo, E; Ghianda, D; Levante, D; Guerrini, C; Bonacasa, R; Solerte, S B

2009-01-01

264

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

SciTech Connect

Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges the utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance due to variable parameters such as battery state-of-charge, coupling factor, and coil misalignment. This paper presents the implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation. The proposed SiC MOSFET based single phase active front end rectifier with PFC resulted in >97% efficiency at 137mm air-gap and >95% efficiency at 160mm air-gap.

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

2014-01-01

265

Correction of Murine Hemophilia A and Immunological Differences of Factor VIII Variants Delivered by Helper-dependent Adenoviral Vectors  

Microsoft Academic Search

Bioengineering of the factor VIII (FVIII) molecule has led to the production of variants that overcome poor secretion and\\/or rapid inactivation. We tested six modified FVIII variants for in vivo efficacy by expressing them from helper-dependent adenoviral (HD-Ad) vectors. We constructed a wild-type (WT) variant, a B-domain-deleted (BDD) variant, a point mutant for improved secretion (F309S), a variant with a

Vincenzo Cerullo; Michael P Seiler; Viraj Mane; Racel Cela; Christian Clarke; Randal J Kaufman; Steven W Pipe; Brendan Lee

2007-01-01

266

A practical methodology to measure unbiased gas chromatographic retention factor vs. temperature relationships.  

PubMed

Compound identification continues to be a major challenge. Gas chromatography-mass spectrometry (GC-MS) is a primary tool used for this purpose, but the GC retention information it provides is underutilized because existing retention databases are experimentally restrictive and unreliable. A methodology called "retention projection" has the potential to overcome these limitations, but it requires the retention factor (k) vs. T relationship of a compound to calculate its retention time. Direct methods of measuring k vs. T relationships from a series of isothermal runs are tedious and time-consuming. Instead, a series of temperature programs can be used to quickly measure the k vs. T relationships, but they are generally not as accurate when measured this way because they are strongly biased by non-ideal behavior of the GC system in each of the runs. In this work, we overcome that problem by using the retention times of 25 n-alkanes to back-calculate the effective temperature profile and hold-up time vs. T profiles produced in each of the six temperature programs. When the profiles were measured this way and taken into account, the k vs. T relationships measured from each of two different GC-MS instruments were nearly as accurate as the ones measured isothermally, showing less than two-fold more error. Furthermore, temperature-programmed retention times calculated in five other laboratories from the new k vs. T relationships had the same distribution of error as when they were calculated from k vs. T relationships measured isothermally. Free software was developed to make the methodology easy to use. The new methodology potentially provides a relatively fast and easy way to measure unbiased k vs. T relationships. PMID:25496658

Peng, Baijie; Kuo, Mei-Yi; Yang, Panhia; Hewitt, Joshua T; Boswell, Paul G

2014-12-29

267

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

NASA Technical Reports Server (NTRS)

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

Freedman, Adam; McWatters, Dalia; Spencer, Michael

2006-01-01

268

Small fields output factors measurements and correction factors determination for several detectors for a CyberKnife{sup Registered-Sign} and linear accelerators equipped with microMLC and circular cones  

SciTech Connect

Purpose: The use of small photon fields is now an established practice in stereotactic radiosurgery and radiotherapy. However, due to a lack of lateral electron equilibrium and high dose gradients, it is difficult to accurately measure the dosimetric quantities required for the commissioning of such systems. Moreover, there is still no metrological dosimetric reference for this kind of beam today. In this context, the first objective of this work was to determine and to compare small fields output factors (OF) measured with different types of active detectors and passive dosimeters for three types of facilities: a CyberKnife{sup Registered-Sign} system, a dedicated medical linear accelerator (Novalis) equipped with m3 microMLC and circular cones, and an adaptive medical linear accelerator (Clinac 2100) equipped with an additional m3 microMLC. The second one was to determine the k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}} correction factors introduced in a recently proposed small field dosimetry formalism for different active detectors.Methods: Small field sizes were defined either by microMLC down to 6 Multiplication-Sign 6 mm{sup 2} or by circular cones down to 4 mm in diameter. OF measurements were performed with several commercially available active detectors dedicated to measurements in small fields (high resolution diodes: IBA SFD, Sun Nuclear EDGE, PTW 60016, PTW 60017; ionizing chambers: PTW 31014 PinPoint chamber, PTW 31018 microLion liquid chamber, and PTW 60003 natural diamond). Two types of passive dosimeters were used: LiF microcubes and EBT2 radiochromic films.Results: Significant differences between the results obtained by several dosimetric systems were observed, particularly for the smallest field size for which the difference in the measured OF reaches more than 20%. For passive dosimeters, an excellent agreement was observed (better than 2%) between EBT2 and LiF microcubes for all OF measurements. Moreover, it has been shown that these passive dosimeters do not require correction factors and can then be used as reference dosimeters. Correction factors for the active detectors have then been determined from the mean experimental OF measured by the passive dosimeters.Conclusions: Four sets of correction factors needed to apply the new small field dosimetry formalism are provided for several active detectors. A protocol for small photon beams OF determination based on passive dosimeters measurements has been recently proposed to French radiotherapy treatment centers.

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

2013-07-15

269

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

270

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

271

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

PubMed Central

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

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

2014-01-01

272

Study of effective carrier lifetime and ideality factor of BPW 21 and BPW 34B photodiodes from above room temperature to liquid nitrogen temperature  

NASA Astrophysics Data System (ADS)

In the present work we have studied the temperature dependence of two most important characteristics of the photodiodes (BPW 21and BPW 34B), namely, the ideality factor and the carrier lifetime; both of which are found to change significantly at low temperature. The effective carrier lifetime measured by the Open Circuit Voltage Decay method (OCVD) shows a gradual increase in value from 350 K to about 250 K then sharply decreases by about thirty percent of its highest value at liquid nitrogen temperature, the trend being similar for both the devices. The dark forward current-voltage characteristics over the same temperature range yield the value of ideality factor which increases nearly by a factor of three for both the photodiodes at the liquid nitrogen temperature. The nature of variation of both the parameters has been qualitatively accounted for in terms of the recent tunneling models. The data generated for the first time for the devices and their broad theoretical understanding will help to improve design and application of the photodiodes, particularly at low temperature.

Dalapati, P.; Manik, N. B.; Basu, A. N.

2015-01-01

273

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

274

Influence of anelastic corrections to the temperature derivatives of seismic velocities on 3-D wavefields in geodynamically derived seismic mantle heterogeneity  

NASA Astrophysics Data System (ADS)

Recently, we have developed a new joint forward modeling approach to test geodynamic hypotheses directly against seismic data: Seismic heterogeneity is predicted by converting the temperature field of a high-resolution 3-D mantle circulation model into seismic velocities using thermodynamic models of mantle mineralogy. 3-D global wave propagation in the synthetic elastic structures is then simulated using a spectral element method. Being based on forward modelling only, this approach allows us to generate synthetic wavefields and seismograms independently of seismic observations. The statistics of observed long-period body wave traveltime variations show a markedly different behaviour for P- and S-waves: the standard deviation of P-wave delay times stays almost constant with ray turning depth, while that of the S-wave delay times increases strongly throughout the mantle. In an earlier study, we showed that synthetic traveltime variations computed for an isochemical mantle circulation model with strong core heating can reproduce these different trends. This was taken as a strong indication that seismic heterogeneity in the lower mantle is likely dominated by thermal variations on large length-scales; that is, relevant for long-period body waves. To test the robustness of our earlier conclusion, we address now the question on the influence of anelasticity on the standard deviation of synthetic traveltime variations. Owing to the differences in seismic frequency content between laboratory measurements (MHz to GHz) and the Earth (mHz to Hz), the seismic velocities given in the mineralogical model need to be adjusted; that is, corrected for dispersion due to anelastic effects. This correction will increase the sensitivity of the seismic velocities to temperature variations. The magnitude of this increase in sensitivity depends on absolute temperature, frequency, the frequency dependence of attenuation and the activation enthalpy of the dissipative process. Especially the latter two are poorly known for mantle minerals and our results show that variations in activation enthalpy produce the largest differences in temperature sensitivity with respect to the purely elastic case. We will present new wave propagation simulations and corresponding statistical analyses of traveltime measurements for different synthetic seismic models spanning the possible range of anelastic velocity conversions while being based on the same mantle circulation model.

Schuberth, Bernhard; Gräber, Claudia; Baykiev, Eldar; Zaroli, Christophe

2014-05-01

275

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

NASA Astrophysics Data System (ADS)

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 k_{Q,Q_o} (or k_{Q,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.

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

2004-09-01

276

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

NASA Astrophysics Data System (ADS)

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

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

2002-02-01

277

Correct dosage of Fog2 and Gata4 transcription factors is critical for fetal testis development in mice  

PubMed Central

Previous reports suggested that humans and mice differ in their sensitivity to the genetic dosage of transcription factors that play a role in early testicular development. This difference implies that testis determination might be somewhat different in these two species. We report that the Fog2 and Gata4 transcription factors are haploinsufficient for testis determination in mice. Whether gonadal sex reversal occurs depends on genetic background (i.e., modifier genes). For example, C57BL/6J (B6) XY mice develop testes if they are heterozygous for a mutant Fog2 (Fog2?) or Gata4 (Gata4ki) allele. However, if the B6 Y chromosome (YB6) is replaced by the AKR Y chromosome (YAKR), B6 Fog2?/+ XYAKR mice develop ovaries, and B6 Gata4ki/+ XYAKR mice develop ovaries and ovotestes (gonads containing both ovarian and testicular tissue). Furthermore, DBA/2J (D2) Fog2?/+ XYAKR mice and (B6 × D2)F1 hybrid Gata4ki/+ XYAKR mice develop testes. Sry is expressed in the mutant XY gonads, indicating that the lack of Sry expression is not the cause of ovarian tissue development in B6 Fog2?/+ or Gata4ki/+ XYAKR mice. However, up-regulation of Sox9 expression, which is critical for normal testicular development, does not occur in mutant XY gonads that develop as ovaries. We conclude that under certain genetic conditions, Sox9 up-regulation depends on the proper dosage of Fog2 and Gata4. We propose that in humans the FOG2 and/or GATA4 genes might be haploinsufficient for normal testis determination and thus could be the cause of some previously unassigned cases of XY gonadal sex reversal. PMID:17848526

Bouma, Gerrit J.; Washburn, Linda L.; Albrecht, Kenneth H.; Eicher, Eva M.

2007-01-01

278

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

NASA Astrophysics Data System (ADS)

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

Singh, S. Somorendro; Ramanathan, R.

2014-10-01

279

Evaluation of Wall Correction Factor of INER's Air-Kerma Primary Standard Chamber and Dose Variation by Source Displacement for HDR 192Ir Brachytherapy  

PubMed Central

The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR) 192Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan). The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the 192Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA) and the National Physical Laboratory (NPL, UK) for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR 192Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR 192Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity. PMID:24222907

Lee, J. H.; Wang, J. N.; Huang, T. T.; Su, S. H.; Chang, B. J.; Su, C. H.; Hsu, S. M.

2013-01-01

280

Exposure levels due to WLAN devices in indoor environments corrected by a time-amplitude factor of distribution of the quasi-stochastic signals.  

PubMed

With the development of radiofrequency technology, radiating quasi-stochastic signals like the wireless local area networks (WLAN), a proper procedure of exposure level assessment is needed. No standardised procedure exists at the moment. While channel power measurement proved to overestimate the field strength, weighting techniques were proposed. The paper compares the exposure levels determined by three different procedures, two of them correcting the field level by weighting. Twenty-three experimental cases of WLAN traffic load are analysed in an indoor environment in controlled conditions. The results show the differences obtained when the duty cycle (DC) method is applied comparatively with the application of weighting based on an amplitude-time correction. Significant exposure level reductions of 52.6-79.2 % from the field determined by frequency domain method and of 36.5-72.8 % from the field determined by the DC weighting method were obtained by time-amplitude method. Specificities of weighting factors probability density functions were investigated and regression analysis was applied for a detailed characterisation of this procedure. PMID:24591729

Miclaus, Simona; Bechet, Paul; Stratakis, Dimitrios

2014-12-01

281

Evaluation of wall correction factor of INER's air-kerma primary standard chamber and dose variation by source displacement for HDR ¹?²Ir brachytherapy.  

PubMed

The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR) ¹?²Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan). The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the ¹?²Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA) and the National Physical Laboratory (NPL, UK) for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR ¹?²Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR ¹?²Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity. PMID:24222907

Lee, J H; Wang, J N; Huang, T T; Su, S H; Chang, B J; Su, C H; Hsu, S M

2013-01-01

282

Characterization of radiation beams used to determinate the correction factor for a CyberKnife® unit reference field using ionization chambers  

NASA Astrophysics Data System (ADS)

This paper aimed to characterize a 6 MV x-ray beam from a Varian® iX linear accelerator in order to obtain the correction factors needed by the IAEA/AAPM new formalism1. The experiments were performed in a liquid water phantom under different irradiation conditions: a) Calibration of the reference field of 10 cm × 10 cm at 90 cm SSD and 10 cm depth was carried out according to the TRS-398 protocol using three ionization chambers (IC) calibrated in different reference laboratory and b) Measurement of the absorbed dose rate at 70 cm SSD and 10 cm depth in a 10 cm × 10 cm and 5.4 cm × 5.4 cm fields was obtained in order to simulate the CyberKnife® conditions where maximum distance between the source and the detector is equal to 80 cm and the maximum field size is 6 cm diameter. Depending where the IC was calibrated, differences between 0.16% and 2.24% in the absorbed dose rate measured in the 10 cm × 10 cm field at 90 cm SSD were observed, while for the measurements at 70 cm SSD, differences between 1.27% and 3.88% were obtained. For the 5.4 cm × 5.4 cm field, the absorbed dose measured with the three ICs varies between 1.37% and 3.52%. The increase in the difference on the absorbed dose when decreasing the SSD could possibly be associated to scattering radiation generated from the collimators and/or the energy dependence of the ionization chambers to low-energy radiation. The results presented in this work suggest the importance of simulating the CyberKnife® conditions using other linear accelerator for obtaining the correction factors as proposed by the IAEA/AAPM new formalism in order to measure the absorbed dose with acceptable accuracy.

Aragón-Martínez, Nestor; Gómez-Muñoz, Arnulfo; Massillon-JL, Guerda

2014-11-01

283

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

284

Toward accurate thermochemistry of the (24)MgH, (25)MgH, and (26)MgH molecules at elevated temperatures: Corrections due to unbound states.  

PubMed

The total partition functions QT and their first two moments Q(')T and Q(?)T, together with the isobaric heat capacities CpT, are computed a priori for three major MgH isotopologues on the temperature range of T = 100-3000 K using the recent highly accurate potential energy curve, spin-rotation, and non-adiabatic correction functions of Henderson et al. [J. Phys. Chem. A 117, 13373 (2013)]. Nuclear motion computations are carried out on the ground electronic state to determine the (ro)vibrational energy levels and the scattering phase shifts. The effect of resonance states is found to be significant above about 1000 K and it increases with temperature. Even very short-lived states, due to their relatively large number, have significant contributions to QT at elevated temperatures. The contribution of scattering states is around one fourth of that of resonance states but opposite in sign. Uncertainty estimates are given for the possible error sources, suggesting that all computed thermochemical properties have an accuracy better than 0.005% up to 1200 K. Between 1200 and 2500 K, the uncertainties can rise to around 0.1%, while between 2500 K and 3000 K, a further increase to 0.5% might be observed for Q(?)T and CpT, principally due to the neglect of excited electronic states. The accurate thermochemical data determined are presented in the supplementary material for the three isotopologues of (24)MgH, (25)MgH, and (26)MgH at 1 K increments. These data, which differ significantly from older standard data, should prove useful for astronomical models incorporating thermodynamic properties of these species. PMID:25573549

Szidarovszky, Tamás; Császár, Attila G

2015-01-01

285

Toward accurate thermochemistry of the 24MgH, 25MgH, and 26MgH molecules at elevated temperatures: Corrections due to unbound states  

NASA Astrophysics Data System (ADS)

The total partition functions Q(T) and their first two moments Q ' (T) and Q ? (T), together with the isobaric heat capacities C p (T), are computed a priori for three major MgH isotopologues on the temperature range of T = 100-3000 K using the recent highly accurate potential energy curve, spin-rotation, and non-adiabatic correction functions of Henderson et al. [J. Phys. Chem. A 117, 13373 (2013)]. Nuclear motion computations are carried out on the ground electronic state to determine the (ro)vibrational energy levels and the scattering phase shifts. The effect of resonance states is found to be significant above about 1000 K and it increases with temperature. Even very short-lived states, due to their relatively large number, have significant contributions to Q (T) at elevated temperatures. The contribution of scattering states is around one fourth of that of resonance states but opposite in sign. Uncertainty estimates are given for the possible error sources, suggesting that all computed thermochemical properties have an accuracy better than 0.005% up to 1200 K. Between 1200 and 2500 K, the uncertainties can rise to around 0.1%, while between 2500 K and 3000 K, a further increase to 0.5% might be observed for Q ? (T) and C p (T), principally due to the neglect of excited electronic states. The accurate thermochemical data determined are presented in the supplementary material for the three isotopologues of 24MgH, 25MgH, and 26MgH at 1 K increments. These data, which differ significantly from older standard data, should prove useful for astronomical models incorporating thermodynamic properties of these species.

Szidarovszky, Tamás; Császár, Attila G.

2015-01-01

286

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

287

Circulating Ang-2 mRNA expression levels: looking ahead to a new prognostic factor for NSCLC [corrected].  

PubMed

Non-small cell lung cancer (NSCLC) is the most common cancer and the leading cause of death from cancer worldwide. Antiangiogenic strategies directed towards tumor stroma are becoming gold standard in NSCLC treatment and researchers have been searching for biomarkers to identify patients for whom therapy with antiangiogenic inhibitors may be most beneficial and the importance of these as prognostic factors in NSCLC. The purpose of this study was to evaluate the prognostic value of circulating Ang-2 mRNA levels prior to treatment in NSCLC patients. The mRNA levels were determined by quantitative real-time PCR in the peripheral blood of 92 NSCLC patients. Our results demonstrate that patients with high circulating Ang-2 mRNA levels have diminished overall survival when compared to those with low mRNA levels (20.3 months vs 34.3 months, respectively; Log Rank Test, p = 0.016), when considering all NSCLC stages and this difference is even bigger when considering only patients with stage IV (15.9 months vs 31.3 months, respectively; Log Rank Test, p = 0.036). Moreover, circulating Ang-2 mRNA levels independently determine overall survival, and the concordance (c) index analysis showed that the definition of a nomogram that contains information regarding tumor stage, patients' smoking status and circulating Ang-2 mRNA levels present an increased capacity to predict overall survival in NSCLC patients (c-index 0.798). These results suggest that this nomogram could serve as a unique and practical tool to determine prognosis in NSCLC, not relying on the availability of adequate surgical or biopsy specimens of NSCLC. Attending to our results, the circulating Ang-2 mRNA levels should also be included in the design of preclinical studies and clinical trials involving antiangiogenic drugs targeting Ang-2, to guide adequate patient stratification and dose selection and increasing the likelihood of benefit to a level that is acceptable to patients and clinicians. PMID:24587185

Coelho, Ana L; Araújo, António; Gomes, Mónica; Catarino, Raquel; Marques, Agostinho; Medeiros, Rui

2014-01-01

288

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-...

289

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 ...

Mr Clark

2012-10-31

290

Temperature dependence of the Westcott g-factor for neutron capture reactions in ENDF/B-VI  

SciTech Connect

The Westcott g-factors, which allow the user to determine reaction rates for nuclear reactions taking place at various temperatures, have been calculated using data from the Evaluated Neutron Nuclear Data library, ENDF-VI. The nuclides chosen have g-factors which are significantly different from unity and result in different reaction rates compared to nuclides whose neutron capture cross section varies as the reciprocal of the neutron`s velocity. Values are presented as a function of temperature up to 400{degrees}C.

Holden, N.E.

1993-08-01

291

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

NASA Astrophysics Data System (ADS)

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

Gusakova, Maria; Karlin, Lev

2014-05-01

292

Quantitative Analysis of the Head Scatter and Jaw Transmission Correction Factor for Commissioning of Enhanced Dynamic Wedge Fields Using a MapCHECK 2 Diode Array  

NASA Astrophysics Data System (ADS)

Quality assurance in radiation oncology treatment planning requires independent verification of dose to be delivered to a patient through "second check" calculations for simple plans as well as planar dose fluence measurements for more complex treatments, such as intensity modulated radiation treatments (IMRT). Discrepancies between treatment planning system (TPS) and second check calculations created a need for treatment plan verification using a two dimensional diode array for Enhanced Dynamic Wedge (EDW) fields. While these measurements met clinical standards for treatment, they revealed room for improvement in the EDW model. The purpose of this study is to analyze the head scatter and jaw transmission effects of the moving jaw in EDW fields by measuring dose profiles with a two dimensional diode array in order to minimize differences between the manufacturer provided fluence table (Golden Segmented Treatment Table) and actual machine output. The jaw transmission effect reduces the dose gradient in the wedge direction due to transmission photons adding dose to the heel region of the field. The head scatter effect also reduces the gradient in the dose profile due to decreased accelerator output at increasingly smaller field sizes caused by the moving jaw. The field size continuously decreases with jaw motion, and thus the toe region of the wedge receives less dose than anticipated due to less head scatter contribution for small field sizes. The Golden Segmented Treatment Table (GSTT) does not take these factors into account since they are specific to each individual machine. Thus, these factors need to be accounted for in the TPS to accurately model the gradient of the wedge. The TPS used in this clinic uses one correction factor (transmission factor) to account for both effects since both factors reduce the dose gradient of the wedge. Dose profile measurements were made for 5x5 cm2, 10x10 cm2, and 20x20 cm2 field sizes with open fields and 10°, 15°, 20°, 25°, 30°, 45°, and 60° wedges for 6 MV and 18 MV beams and compared with TPS generated profiles. The transmission factor was adjusted for the 18 MV beam to obtain a better correlation between planned and measured dose gradient by reducing the gradient of the wedge in the TPS. This correction resulted in an average and maximum pass rate improvement for patient plans at a distance to agreement of 3% 3mm of 1.07% and 3.9% respectively. The off axis ratio data in the second check calculation software was also adjusted to bring the dose agreement between the initial TPS calculation and second check calculation within clinical standards. This study demonstrated the ability to adjust the EDW gradient in a treatment planning system to improve the differences in machine output specific to each machine and the manufacturer provided GSTT.

Dickerson, Edward C.

293

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

NASA Astrophysics Data System (ADS)

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

Oteo, I.

2014-12-01

294

Metabolic shift in liver: Correlation between perfusion temperature and hypoxia inducible factor-1?  

PubMed Central

AIM: To study at what temperature the oxygen carried by the perfusate meets liver requirements in a model of organ perfusion. METHODS: In this study, we correlated hypoxia inducible factor (HIF)-1? expression to the perfusion temperature and the hepatic oxygen uptake in a model of isolated perfused rat liver. Livers from Wistar rats were perfused for 6 h with an oxygenated medium at 10, 20, 30 and 37?°C. Oxygen uptake was measured by an oxygen probe; lactate dehydrogenase activity, lactate release and glycogen were measured spectrophotometrically; bile flow was gravitationally determined; pH of the perfusate was also evaluated; HIF-1? mRNA and protein expression were analyzed by real time-polymerase chain reaction and ELISA, respectively. RESULTS: Livers perfused at 10 and 20?°C showed no difference in lactate dehydrogenase release after 6 h of perfusion (0.96 ± 0.23 vs 0.93 ± 0.09 mU/min per g) and had lower hepatic damage as compared to 30 and 37?°C (5.63 ± 0.76 vs 527.69 ± 45.27 mU/min per g, respectively, Ps < 0.01). After 6 h, tissue ATP was significantly higher in livers perfused at 10 and 20?°C than in livers perfused at 30 and 37?°C (0.89 ± 0.06 and 1.16 ± 0.05 vs 0.57 ± 0.09 and 0.33 ± 0.08 nmol/mg, respectively, Ps < 0.01). No sign of hypoxia was observed at 10 and 20?°C, as highlighted by low lactate release respect to livers perfused at 30 and 37?°C (121.4 ± 12.6 and 146.3 ± 7.3 vs 281.8 ± 45.3 and 1094.5 ± 71.7 nmol/mL, respectively, Ps < 0.02), and low relative HIF-1? mRNA (0.40 ± 0.08 and 0.20 ± 0.03 vs 0.60 ± 0.20 and 1.47 ± 0.30, respectively, Ps < 0.05) and protein (3.72 ± 0.16 and 3.65 ± 0.06 vs 4.43 ± 0.41 and 6.44 ± 0.82, respectively, Ps < 0.05) expression. CONCLUSION: Livers perfused at 10 and 20?°C show no sign of liver injury or anaerobiosis, in contrast to livers perfused at 30 and 37?°C. PMID:25632183

Ferrigno, Andrea; Di Pasqua, Laura Giuseppina; Bianchi, Alberto; Richelmi, Plinio; Vairetti, Mariapia

2015-01-01

295

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

PubMed

Sky view factor (SVF), which is an indicator of urban canyon geometry, affects the surface energy balance, local air circulation, and outdoor thermal comfort. This study focused on a continuous and long-term meteorological observation system to investigate the effects of SVF on outdoor thermal conditions and physiological equivalent temperature (PET) in the central business district (CBD) of Beijing (which is located within Chaoyang District), specifically addressed current knowledge gaps for SVF-PET relationships in cities with typical continental/microthermal climates. An urban sub-domain scale model and the RayMan model were used to diagnose wind fields and to calculate SVF and long-term PET, respectively. Analytical results show that the extent of shading contributes to variations in thermal perception distribution. Highly shaded areas (SVF <0.3) typically exhibit less frequent hot conditions during summer, while enduring longer periods of cold discomfort in winter than moderately shaded areas (0.3< SVF <0.5) and slightly shaded areas (SVF >0.5), and vice versa. Because Beijing has a monsoon-influenced humid continental climate with hot summers and long, cold, windy, and dry winters, a design project that ideally provides moderate shading should be planned to balance hot discomfort in summer and cold discomfort in winter, which effectively prolongs the comfort periods in outdoor spaces throughout the entire year. This research indicate that climate zone characteristics, urban environmental conditions, and thermal comfort requirements of residents must be accounted for in local-scale scientific planning and design, i.e., for urban canyon streets and residential estates. PMID:24842520

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

2015-03-01

296

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

NASA Astrophysics Data System (ADS)

Sky view factor (SVF), which is an indicator of urban canyon geometry, affects the surface energy balance, local air circulation, and outdoor thermal comfort. This study focused on a continuous and long-term meteorological observation system to investigate the effects of SVF on outdoor thermal conditions and physiological equivalent temperature (PET) in the central business district (CBD) of Beijing (which is located within Chaoyang District), specifically addressed current knowledge gaps for SVF-PET relationships in cities with typical continental/microthermal climates. An urban sub-domain scale model and the RayMan model were used to diagnose wind fields and to calculate SVF and long-term PET, respectively. Analytical results show that the extent of shading contributes to variations in thermal perception distribution. Highly shaded areas (SVF <0.3) typically exhibit less frequent hot conditions during summer, while enduring longer periods of cold discomfort in winter than moderately shaded areas (0.3< SVF <0.5) and slightly shaded areas (SVF >0.5), and vice versa. Because Beijing has a monsoon-influenced humid continental climate with hot summers and long, cold, windy, and dry winters, a design project that ideally provides moderate shading should be planned to balance hot discomfort in summer and cold discomfort in winter, which effectively prolongs the comfort periods in outdoor spaces throughout the entire year. This research indicate that climate zone characteristics, urban environmental conditions, and thermal comfort requirements of residents must be accounted for in local-scale scientific planning and design, i.e., for urban canyon streets and residential estates.

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

2014-05-01

297

Estradiol and Incubation Temperature Modulate Regulation of Steroidogenic Factor 1 in the Developing  

E-print Network

for sex deter- mination, with incubation temperature of the egg determining go- nadal sex. At higher in embryos 1) incubating at three different temperatures, 2) after treating eggs with estrogen at a male by the incubation temperature of eggs during embryogenesis (1, 2). Genotypic sex determination (GSD) occurs

Crews, David

298

Temperature  

NSDL National Science Digital Library

This topic in depth begins with the About Temperature (1) Web site, written by Beverly T. Lynds of Unidata, which is a program that works to enable university researchers and educators to acquire and use atmospheric and related data. The one-page site explains what temperature is, the development of thermometers, heat and thermodynamics, and other related topics. The second site is maintained by the University of Execter's Centre for Innovation in Mathematics Teaching. Actually an online tool called Conversion Calculator for Units of Temperature (2), the site allows users to type in any value, choose a significant figure, press "convert it," and get that value in Kelvin, Celsius, Fahrenheit, r'aumur, and rankine units. The next site is a lesson plan from AskEric.com entitled Temperature: Is it Hot or Cold? (3). Written for 2nd graders, the lesson demonstrates to how to read thermometers, determine their rise or fall, record temperatures, and take temperatures of various items. The fourth site, Surface Temperature Analysis (4), is presented by NASA's Goddard Institute for Space Studies. Here, visitors can view graphs, maps, animations, and station data of global surface temperatures. For example, the animation covers 12-month means from 1971 to 1999. The History Behind the Thermometer (5) Web site, from About.com, explores what a thermometer is, how it works, and how it came into being. The sixth site, entitled Science Shack (6) and offered by the BBC, answers the question, Why do we have two different temperature scales, Celsius and Fahrenheit? The site explains how to create your own thermometer like Galileo's, tells how it works, and why we use other types today. The next site is provided by National Oceanic and Atmospheric Administration (NOAA) and presents US State temperature extremes and drought information (7). Visitors can see all-time temperature maximums and minimums by state, monthly temperatures by state, and more. The last site is an all-inclusive temperature site called Temperature World (8). Everything from news, science, organizations, general interest, games, and more -- all related to temperature -- can be found here.

Brieske, Joel A.

2002-01-01

299

Debye-Waller factor through the glass transition temperature in a-selenium, by incoherent inelastic neutron scattering  

NASA Astrophysics Data System (ADS)

We report, in this work, Incoherent Inelastic Neutron Scattering (IINS) measurements in amorphous bulk selenium. Taking into account the low frequency Vibrational Density-of-States(VDOS), we study the modification introduced in the Debye-Waller factor by increasing temperature through the glass transition temperature ( Tg). The occurrence, in the vibrational density-of-states, of a ? 2 dependence in the acoustic region, allowed us to apply the Debye theory from which the variations of the Deybe-Waller factor are calculated in addition. It is shown that the main contribution to it is given by the acoustic region of the vibrational density of states and has a faster increase for temperatures above Tg.

Galli, G.; Migliardo, P.; Bellissent, R.; Reichardt, W.

1986-01-01

300

High temperature-mediated adaptations in plant architecture require the bHLH transcription factor PIF4.  

PubMed

Exposure of Arabidopsis plants to high temperature (28 degrees C) results in a dramatic change in plant development. Responses to high temperature include rapid extension of plant axes, leaf hyponasty, and early flowering. These phenotypes parallel plant responses to the threat of vegetational shade and have been shown to involve the hormone auxin. In this work, we demonstrate that high temperature-induced architectural adaptations are mediated through the bHLH transcriptional regulator PHYTOCHROME INTERACTING FACTOR 4 (PIF4). Roles for PIF4 have previously been established in both light and gibberellin (GA) signaling, through interactions with phytochromes and DELLA proteins, respectively. Mutants deficient in PIF4 do not display elongation responses or leaf hyponasty upon transfer to high temperature. High temperature-mediated induction of the auxin-responsive gene IAA29 is also abolished in these plants. An early flowering response to high temperature is maintained in pif4 mutants, suggesting that architectural and flowering responses operate via separate signaling pathways. The role of PIF4 in temperature signaling does not, however, appear to operate through interaction with either phytochrome or DELLA proteins, suggesting the existence of a novel regulatory mechanism. We conclude that PIF4 is an important component of plant high temperature signaling and integrates multiple environmental cues during plant development. PMID:19249207

Koini, Maria A; Alvey, Liz; Allen, Trudie; Tilley, Ceinwen A; Harberd, Nicholas P; Whitelam, Garry C; Franklin, Keara A

2009-03-10

301

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

USGS Publications Warehouse

Temperature is an important variable structuring lotic biotas, but little is known about how montane landscapes function to determine stream temperatures. We developed an a priori hypothesis that was used to predict how watershed elements would interact to affect stream temperatures. The hypothesis was tested in a series of path analyses using temperature data from 26 sites on second-order to fourth-order streams across a fifth-order Rocky Mountain watershed. Based on the performance of the first hypothesis, two revised versions of the hypothesis were developed and tested that proved to be more accurate than the original hypothesis. The most plausible of the revised hypotheses accounted for 82 percent of the variation in maximum stream temperature, had a predicted data structure that did not deviate from the empirical data structure, and was the most parsimonious. The final working hypothesis suggested that stream temperature maxima were directly controlled by a large negative effect from mean basin elevation (direct effect = -0.57, p < 0.01) and smaller effects from riparian tree abundance (direct effect = -0.28, p = 0.03), and cattle density (direct effect = 0.24, p = 0.05). Watershed slope, valley constraint, and the abundance of grass across a watershed also affected temperature maxima, but these effects were indirect and mediated through cattle density and riparian trees. Three variables included in the a priori hypothesis - watershed aspect, stream width, and watershed size - had negligible effects on maximum stream temperatures and were omitted from the final working hypothesis.

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

2001-01-01

302

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...

303

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

304

Monte Carlo calculations of the ionization chamber wall correction factors for 192Ir and 60Co gamma rays and 250 kV x-rays for use in calibration of 192Ir HDR brachytherapy sources.  

PubMed

As in the method for the calibration of 192Ir high-dose-rate (HDR) brachytherapy sources, the ionization chamber wall correction factor A(w), is needed for 192Ir and 60Co gamma rays and 250 kV x-rays. This factor takes into account the variation in chamber response due to the attenuation of the photon beam in the chamber wall and build-up cap and the contribution of scattered photons. Monte Carlo calculations were performed using the EGS4 code system with the PRESTA algorithm, to calculate the A(w) factor for 51 commercial ionization chambers and build-up caps exposed to the typical energy spectrum of 192Ir and 60Co gamma rays and 250 kV x-rays. The calculated A(w) correction factors for 192Ir and 60Co sources and 250 kV x-rays agree very well to within 0.1% with published experimental data (the statistical uncertainty is less than 0.1% of the calculated correction factor value). For the 192Ir sources, A(w) varies from 0.973 to 0.993 and for the 250 kV x-rays the minimum value of A(w) for all chambers studied is 0.983. The calculated A(w) correction factors can be used to calculate the air kerma calibration factor of HDR brachytherapy sources, when interpolative methods are considered, contributing to the reduction in the overall uncertainties in the calibration procedure. PMID:10473203

Ferreira, I H; de Almeida, C E; Marre, D; Marechal, M H; Bridier, A; Chavaudra, J

1999-08-01

305

Resource Supply Overrides Temperature as a Controlling Factor of Marine Phytoplankton Growth  

PubMed Central

The universal temperature dependence of metabolic rates has been used to predict how ocean biology will respond to ocean warming. Determining the temperature sensitivity of phytoplankton metabolism and growth is of special importance because this group of organisms is responsible for nearly half of global primary production, sustains most marine food webs, and contributes to regulate the exchange of CO2 between the ocean and the atmosphere. Phytoplankton growth rates increase with temperature under optimal growth conditions in the laboratory, but it is unclear whether the same degree of temperature dependence exists in nature, where resources are often limiting. Here we use concurrent measurements of phytoplankton biomass and carbon fixation rates in polar, temperate and tropical regions to determine the role of temperature and resource supply in controlling the large-scale variability of in situ metabolic rates. We identify a biogeographic pattern in phytoplankton metabolic rates, which increase from the oligotrophic subtropical gyres to temperate regions and then coastal waters. Variability in phytoplankton growth is driven by changes in resource supply and appears to be independent of seawater temperature. The lack of temperature sensitivity of realized phytoplankton growth is consistent with the limited applicability of Arrhenius enzymatic kinetics when substrate concentrations are low. Our results suggest that, due to widespread resource limitation in the ocean, the direct effect of sea surface warming upon phytoplankton growth and productivity may be smaller than anticipated. PMID:24921945

Marañón, Emilio; Cermeño, Pedro; Huete-Ortega, María; López-Sandoval, Daffne C.; Mouriño-Carballido, Beatriz; Rodríguez-Ramos, Tamara

2014-01-01

306

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

307

Temperature  

NASA Technical Reports Server (NTRS)

The problems in human comfort in heat stress are emphasized, with less emphasis placed upon cold exposure problems. Physiological parameters related to human thermal interactions are discussed, as well as data concerning thermal protective clothing. The energy balance equation, heat transfer equation, thermal comfort, heat stress, and cold stress are also considered. A two node model of human temperature regulation in FORTRAN is appended.

Berenson, P. J.; Robertson, W. G.

1973-01-01

308

Factors contributing to the degradation of poly(p-phenylene benzobisoxazole) (PBO) fibers under elevated temperature and humidity conditions  

E-print Network

derivative of TA such as terephthaloyl chloride in a poly-phosphoric acid (PPA) solution [1] as shown in Figure 2. 5 Figure 2. Synthesis of PBO In this synthesis, poly-phosphoric acid serves three different functions, acting as solvent... FACTORS CONTRIBUTING TO THE DEGRADATION OF POLY(P- PHENYLENE BENZOBISOXAZOLE) (PBO) FIBERS UNDER ELEVATED TEMPERATURE AND HUMIDITY CONDITIONS A Thesis by #0;-#0;2#0;6#0;(#0;3#0;+#0;#3;#0;0#0;#17;#0...

O'Neil, Joseph M

2006-10-30

309

Factors affecting platinum extraction from used reforming catalysts in iodine solutions at temperatures up to 95 °C  

Microsoft Academic Search

Platinum extraction from the spent reforming catalysts in iodine–iodide solutions at temperatures from 25 to 95 °C was investigated. The reforming catalyst mostly consists of a porous gamma alumina support with metallic platinum finely dispersed on the walls of the nano-pores of the catalyst support. The effect of a variety of factors, including catalyst particle size, impeller agitation speed, reactant concentrations,

Amir Zanjani; Morteza Baghalha

2009-01-01

310

Factorize  

NSDL National Science Digital Library

This interactive applet allows a student to visually explore the concept of factors by creating different rectangular arrays for a number. The user constructs the array by clicking and dragging on a grid. The length and width of the array are factors of the number. A student can elect an option of a randomly selected number or the student selects his own number between 2 and 50. Exploration questions are included to promote student discovery of mathematical concepts with factors.

2000-01-01

311

Factors affecting temperature variation and habitat use in free-ranging diamondback terrapins.  

PubMed

Measuring the thermal conditions of aquatic reptiles with temperature dataloggers is a cost-effective way to study their behavior and habitat use. Temperature dataloggers are a particularly useful and informative approach to studying organisms such as the estuarine diamondback terrapin (Malaclemys terrapin) that inhabits a dynamic environment often inaccessible to researchers. We used carapace-mounted dataloggers to measure hourly carapace temperature (Tc) of free-ranging terrapins in South Carolina from October 2007 to 2008 to examine the effects of month, sex, creek site, and tide on Tc and to determine the effects of month, sex, and time of day on terrapin basking frequency. Simultaneous measurements of environmental temperatures (Te; shallow mud, deep mud, water) allowed us to make inferences about terrapin microhabitat use. Terrapin Tc differed significantly among months and creek and between sexes. Terrapin microhabitat use also varied monthly, with shallow mud temperature being the best predictor of Tc November-March and water temperature being the best predictor of Tc April-October. Terrapins basked most frequently in spring and fall and males basked more frequently than females. Our study contributes to a fuller understanding of terrapin thermal biology and provides support for using dataloggers to investigate behavior and habitat use of aquatic ectotherms inhabiting dynamic environments. PMID:25086975

Akins, C D; Ruder, C D; Price, S J; Harden, L A; Gibbons, J W; Dorcas, M E

2014-08-01

312

The influence of environmental factors on the temperature of the radiosonde thermistor  

NASA Astrophysics Data System (ADS)

A technique was developed to calculate the radiosonde temperature error as a function of altitude under different environmental conditions. The environmental conditions analyzed include the surface (or cloud) temperature, the atmospheric gaseous constinuents, the aerosol and thermodynamic structure of the atmosphere, the solar elevation angle, the solar albedo, the rise rate of the balloon, and the atmospheric density. The heat balance equations for the thermistor and lead wires were derived and a sensitivity analysis performed to establish the significance of each heating term. The Air Force LOWTRAN 6 code was used to model the solar and infrared irradiation of the thermistor in terms of the environmental parameters. LOWTRAN 6 output was then used to generate the radiation input to the heat balance equations of the thermistor and lead wires. The temperature error of the radiosonde was derived by solving these heat balance equations. This technique for calculating the radiosonde temperature error was validated by comparing with data from flights of experimental radiosondes containing the Standard NWS radiosonde thermistor and three other thermistors with different radiative coatings. Results suggest that the radiosonde temperature error is likely to differ at different latitudes and solar elevation angles because of differing radiative fluxes to the thermistor and because of differing atmospheric temperature profiles.

Luers, James K.

313

Deconvolving temperature and substrate effects on soil heterotrophic respiration under multiple global change factors in mixed grass prairie  

NASA Astrophysics Data System (ADS)

The temperature sensitivity of soil organic matter (SOM) decomposition exposed to elevated CO2 and warming represents a substantial source of uncertainty in predicting climate-carbon feedbacks. Here, we evaluated temperature responses of soil heterotrophic respiration via soil laboratory incubations at the Prairie Heating and CO2 Enrichment experiment. Soils were collected from plots with and without native vegetation so as to examine plant-mediated effects on temperature sensitivity of SOM decomposition under simulated climate change. Thus, soils were exposed to full factorial combinations of elevated CO2, warming and vegetation removal for four years prior to sampling. Incubations were conducted for 60 days at optimal water content (60% of field capacity) and 15, 22 or 30 °C. Total soil C content was measured prior to the start of incubations, and soil respiration was measured 11 times throughout the incubation. Data were analyzed in the context of a Bayesian model where respiration of the fast (aka ';labile') and slow (aka ';recalcitrant') soil C pools were determined by separate Arrhenius-type temperature sensitivity functions as well as by the pool size. We tested competing hypotheses that differences in soil heterotrophic respiration under the different treatments could be explained by 1) changes in the exponential temperature sensitivity (Q10), 2) changes in the base rate, or 3) changes in the size of the fast and slow pools. The model predictions fit the observed data well (r2 = 0.93) across all treatments. The Q10 of both the fast and slow pools decreased ~40% between the 15 and 30 °C incubation temperature across all treatment levels. The Q10 of the fast pool was lower in the warmed treatment than the control in both fallow and vegetated soils, consistent with thermal acclimation. The Q10 of the fast pool under elevated CO2 and warming was lowest in the fallow soil, but highest in the vegetated soil. This indicates that rhizosphere priming plays a role in temperature sensitivity of SOM decomposition. Overall, the temperature sensitivity of the fast pool was highly sensitive to global change factors and their interactions. On the other hand, there were no differences in temperature sensitivity of the slow pool in response to the global change factors. Similarly, the base rate of the fast pool was sensitive to the global change factors, while the slow pool base rate was not. However, the overall size of the slow pool was significantly affected by the global change factors. Vegetation removal reduced the slow pool by ~19% across all warming x CO2 treatments. This effect was greatest under elevated CO2 (both warmed and control), but non-significant under ambient CO2 and temperature. Importantly, effects mediated through the vegetation were the primary factor determining whether slow pool C was gained or lost under elevated CO2 and warming. Our data-model fusion approach allowed us to deconvolve the effect of reduced substrate availability from temperature sensitivity, and to demonstrate that global change may lead to strong positive C cycling feedbacks.

Tucker, C.; Nie, M.; Pendall, E. G.

2013-12-01

314

The Influence of Environmental Factors on the Temperature of the Radiosonde Thermistor.  

NASA Astrophysics Data System (ADS)

A technique was developed to calculate the radiosonde temperature error as a function of altitude under different environmental conditions. The environmental conditions analyzed include the surface (or cloud) temperature, the atmospheric gaseous constinuents, the aerosol and thermodynamic structure of the atmosphere, the solar elevation angle, the solar albedo, the rise rate of the balloon, and the atmospheric density. The heat balance equations for the thermistor and lead wires were derived and a sensitivity analysis performed to establish the significance of each heating term. The Air Force LOWTRAN 6 code was used to model the solar and infrared irradiation of the thermistor in terms of the environmental parameters. LOWTRAN 6 output was then used to generate the radiation input to the heat balance equations of the thermistor and lead wires. The temperature error of the radiosonde was derived by solving these heat balance equations. This technique for calculating the radiosonde temperature error was validated by comparing with data from flights of experimental radiosondes containing the Standard NWS radiosonde thermistor and three other thermistors with different radiative coatings. Each coating exhibited a different solar absorptance and infrared emission property which allowed the direct calculation of the radiosonde temperature error. The experimental measurements were compared with that predicted by the modeling technique. Comparisons were made between eight flights; four at night, three daylight, and one twilight, which occurred during all seasons of the year and under various surface conditions. The comparisons showed good agreement. For the flights analyzed the temperature error at nighttime was small below 20 Km, and increased negatively above this altitude. At 30 Km the error generally exceeded -1^circK. During the daytime the temperature error was positive and sometimes took on its maximum value as low as 20 Km. At altitudes near 30 Km and above the error often decreased due to influences of an increasing atmospheric temperature. Results from this study suggest that the radiosonde temperature error is likely to differ at different latitudes and solar elevation angles because of differing radiative fluxes to the thermistor and because of differing atmospheric temperature profiles.

Luers, James K.

315

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

PubMed Central

Abstract Residential water heating is linked to growth of pathogens in premise plumbing, which is the primary source of waterborne disease in the United States. Temperature and disinfectant residual are critical factors controlling increased concentration of pathogens, but understanding of how each factor varies in different water heater configurations is lacking. A direct comparative study of electric water heater systems was conducted to evaluate temporal variations in temperature and water quality parameters including dissolved oxygen levels, hydrogen evolution, total and soluble metal concentrations, and disinfectant decay. Recirculation tanks had much greater volumes of water at temperature ranges with potential for increased pathogen growth when set at 49°C compared with standard tank systems without recirculation. In contrast, when set at the higher end of acceptable ranges (i.e., 60°C), this relationship was reversed and recirculation systems had less volume of water at risk for pathogen growth compared with conventional systems. Recirculation tanks also tended to have much lower levels of disinfectant residual (standard systems had 40–600% higher residual), 4–6 times as much hydrogen, and 3–20 times more sediment compared with standard tanks without recirculation. On demand tankless systems had very small volumes of water at risk and relatively high levels of disinfectant residual. Recirculation systems may have distinct advantages in controlling pathogens via thermal disinfection if set at 60°C, but these systems have lower levels of disinfectant residual and greater volumes at risk if set at lower temperatures. PMID:24170969

Brazeau, Randi H.; Edwards, Marc A.

2013-01-01

316

Lower environmental temperature delays and prolongs myogenic regulatory factor expression and muscle differentiation in rainbow trout (Onchrhynchus mykiss) embryos.  

PubMed

The effect of different temperatures (4 degrees C and 12 degrees C) on myogenic regulatory factors (MyoD and myogenin) and myosin heavy chain (MyHC) expression was investigated in rainbow trout (Onchrhynchus mykiss) during early development. MyoD is first switched on at stage 14 [about 5 somites are formed (1/2 epiboly)] while myogenin mRNA is expressed at stage 15 [around 15 somites are visible (2/3 epiboly)] at both temperatures. Subsequently (up to at least stage 20), the most caudal somites exhibit less myogenin mRNA at 4 degrees C compared to 12 degrees C. At the eyed stage (stage 23-24), both myogenin mRNA and protein are present in greater amounts throughout all myotomes at the lower temperature, with mRNA levels in warmer (12 degrees C) embryos at 83% for MyoD and 72% for myogenin of the levels seen in 4 degrees C embryos. Conversely, however, at this same stage, fast-MyHC mRNA and protein are more abundant in 12 degrees C than in 4 degrees C embryos. This indicates relatively advanced muscle differentiation at the warmer temperature. At hatching, myogenin-positive cells are concentrated within the myosepta at both temperatures and they are also sparsely distributed in the myotome at 4 degrees C, but not at 12 degrees C. MyoD, myogenin, and MyHC levels provide an indication of differentiation of muscle cells. These findings suggest that myogenic regulatory factor expression is delayed but prolonged by the lowering of temperature. PMID:11686232

Xie, S Q; Mason, P S; Wilkes, D; Goldspink, G; Fauconneau, B; Stickland, N C

2001-09-01

317

Effect factors of temperature measurements by femtosecond time-resolved CARS  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

318

The effects of incomplete annealing on the temperature dependence of sheet resistance and gage factor in aluminum and phosphorus implanted silicon on sapphire  

NASA Technical Reports Server (NTRS)

Partial annealing of damage to the crystal lattice during ion implantation reduces the temperature coefficient of resistivity of ion-implanted silicon, while facilitating controlled doping. Reliance on this method for temperature compensation of the resistivity and strain-gage factor is discussed. Implantation conditions and annealing conditions are detailed. The gage factor and its temperature variation are not drastically affected by crystal damage for some crystal orientations. A model is proposed to account for the effects of electron damage on the temperature dependence of resistivity and on silicon piezoresistance. The results are applicable to the design of silicon-on-sapphire strain gages with high gage factors.

Pisciotta, B. P.; Gross, C.

1976-01-01

319

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

PubMed Central

Most circadian rhythms are controlled by a major pacemaker located in the hypothalamic suprachiasmatic nucleus. Some of these rhythms, called marker rhythms, serve to characterize the timing of the internal temporal order. However, these variables are susceptible to masking effects as the result of activity, body position, light exposure, environmental temperature and sleep. Recently, wrist skin temperature (WT) has been proposed as a new index for evaluating circadian system status. In light of previous evidence suggesting the important relationship between WT and core body temperature regulation, the aim of this work was to purify the WT pattern in order to obtain its endogenous rhythm with the application of multiple demasking procedures. To this end, 103 subjects (18–24 years old) were recruited and their WT, activity, body position, light exposure, environmental temperature and sleep were recorded under free-living conditions for 1 week. WT demasking by categories or intercepts was applied to simulate a “constant routine” protocol (awakening, dim light, recumbent position, low activity and warm environmental temperature). Although the overall circadian pattern of WT was similar regardless of the masking effects, its amplitude was the rhythmic parameter most affected by environmental conditions. The acrophase and mesor were determined to be the most robust parameters for characterizing this rhythm. In addition, a circadian modulation of the masking effect was found for each masking variable. WT rhythm exhibits a strong endogenous component, despite the existence of multiple external influences. This was evidenced by simultaneously eliminating the influence of activity, body position, light exposure, environmental temperature and sleep. We therefore propose that it could be considered a valuable and minimally-invasive means of recording circadian physiology in ambulatory conditions. PMID:23577201

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

2013-01-01

320

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

PubMed

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

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

2014-08-01

321

Physiological Fluctuations in Brain Temperature as a Factor Affecting Electrochemical Evaluations of Extracellular Glutamate and Glucose in Behavioral Experiments  

PubMed Central

The rate of any chemical reaction or process occurring in the brain depends on temperature. While it is commonly believed that brain temperature is a stable, tightly regulated homeostatic parameter, it fluctuates within 1–4 °C following exposure to salient arousing stimuli and neuroactive drugs, and during different behaviors. These temperature fluctuations should affect neural activity and neural functions, but the extent of this influence on neurochemical measurements in brain tissue of freely moving animals remains unclear. In this Review, we present the results of amperometric evaluations of extracellular glutamate and glucose in awake, behaving rats and discuss how naturally occurring fluctuations in brain temperature affect these measurements. While this temperature contribution appears to be insignificant for glucose because its extracellular concentrations are large, it is a serious factor for electrochemical evaluations of glutamate, which is present in brain tissue at much lower levels, showing smaller phasic fluctuations. We further discuss experimental strategies for controlling the nonspecific chemical and physical contributions to electrochemical currents detected by enzyme-based biosensors to provide greater selectivity and reliability of neurochemical measurements in behaving animals. PMID:23448428

2013-01-01

322

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

E-print Network

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

Crews, David

323

The measurement temperature: an important factor relating physicochemical and adhesive properties of yeast cells to biomaterials.  

PubMed

Flow chambers applied to the study of the initial adhesion process of Candida parapsilosis are rarely found in the literature. The ability of these microorganisms to proliferate and form biofilms in environments at temperatures around 22 or 37 degrees C is reflected in the contamination of laboratory instruments and material or in human implant infections, respectively. The initial interaction between yeasts and substrata is mediated by physicochemical forces, which in turn originate from the physicochemical surface properties of both interacting phases. In this context, this work aims to relate the initial rates of adhesion rates to glass and silicone of Candida parapsilosis, strains 294 and 289, grown at 22 and 37 degrees C with the theoretical predictions of the adhesion process, expressed by the interaction free energies and calculated through the physicochemical parameters, which are also measured at 22 and 37 degrees C. The results indicate that physicochemical parameters of yeasts are changed not only by the culture temperature but also by the measurement temperature; only when the measurement temperature is equal to the growth temperature a coherent relation between in vitro adhesion data and interaction free energies can be established. In this sense, the adhesion to glass is mediated by long-range forces or, what amounts to the same thing, by Lifshitz-van der Waals interaction free energy. On the other hand, the adhesion to silicone rubber seems to be moderated by acid-base interaction free energy, which involves the presence of short-range forces. Based on these results, it can be assumed that the substratum surface properties are directly related to the kind of force acting on the initial microbial adhesion process, while cell surface properties dictate the changes in the strength of the force between different samples. PMID:14972612

Gallardo-Moreno, A M; González-Martín, M L; Pérez-Giraldo, C; Bruque, J M; Gómez-García, A C

2004-03-15

324

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

325

Factors affecting low temperature preservation of the marine rotifer Brachionus rotundiformis Tschugunoff  

Microsoft Academic Search

Experiments were performed to determine suitable conditions for low temperature preservation of small S (Fukuoka) and ultra-small SS (Thai) strains of B. rotundiformis. For this, single rotifers (an adult bearing one egg or a 4-h neonate) were incubated for 10 days in 1 ml seawater (22 ppt salinity). The highest survival was achieved at 10 and 12 °C for S-strain

Mavit Assavaaree; Atsushi Hagiwara; Esther Lubzens

2001-01-01

326

Assessment of factors limiting Klamath River fall Chinook salmon production potential using historical flows and temperatures  

USGS Publications Warehouse

We parameterized and applied a deterministic salmon production model to infer the degree to which river flows and temperatures may limit freshwater production potential of the Klamath River in California. Specific parameter requirements, data sources, and significant assumptions are discussed in detail. Model simulations covered a wide variety of historical hydrologic and meteorologic conditions for 40+ years of environmental data. The model was calibrated only qualitatively, appearing to perform well in predicted outmigrant timing, but overestimating growth. Egg-to-outmigrant survival was near that reported for other rivers north of the Klamath River. Predicted production potential appeared to be determined by multiple causes involving both regularly occurring habitat-related constraints and irregularly occurring exposure to high water temperatures. Simulated production was greatest in years of intermediate water availability and was constrained in both dry and wet years, but for different reasons. Reducing mortality associated with limitations to juvenile habitat, if possible, would be expected to have the highest payoff in increasing production. Water temperature was important in determining predicted production in some years but overall was not predicted to be as important as physical microhabitat. No single mortality cause acted as a true a??bottlenecka?? on productiona?|

Bartholow, John M.; Henriksen, James A.

2006-01-01

327

BTPS correction with dynamic spirometers.  

PubMed

In order to determine the requirements for a proper temperature correction of expired volumes, the temperature of the expired air in the bellows of a dynamic spirometer (Vitalograph) was measured in 10 and 5 subjects at 24 and 12.2 degrees C ambient temperature, respectively. During the short period of forced expiration there was a significant temperature decrease, which showed a linear relationship to the ambient temperature. Temperature differences up to 12-15% occurred within seconds; consequently, the values obtained in bellows-type spirometers for FEV1 and FVC have to be corrected to BTPS at room temperature. There was no correlation between the degree of temperature decrease and the magnitude of expiratory volume. For routine clinical work it suffices to use the room temperature as the variable. PMID:3715213

Forche, G; Harnoncourt, K; Stadlober, E; Zenker, G

1986-01-01

328

Single-crystal sapphire resonator at millikelvin temperatures: Observation of thermal bistability in high-Q factor whispering gallery modes  

SciTech Connect

Resonance modes in single crystal sapphire ({alpha}-Al{sub 2}O{sub 3}) exhibit extremely high electrical and mechanical Q factors ({approx_equal}10{sup 9} at 4 K), which are important characteristics for electromechanical experiments at the quantum limit. We report the cool down of a bulk sapphire sample below superfluid liquid-helium temperature (1.6 K) to as low as 25 mK. The electromagnetic properties were characterized at microwave frequencies, and we report the observation of electromagnetically induced thermal bistability in whispering gallery modes due to the material T{sup 3} dependence on thermal conductivity and the ultralow dielectric loss tangent. We identify ''magic temperatures'' between 80 and 2100 mK, the lowest ever measured, at which the onset of bistability is suppressed and the frequency-temperature dependence is annulled. These phenomena at low temperatures make sapphire suitable for quantum metrology and ultrastable clock applications, including the possible realization of the quantum-limited sapphire clock.

Creedon, Daniel L.; Tobar, Michael E.; Le Floch, Jean-Michel; Reshitnyk, Yarema; Duty, Timothy [School of Physics (M013), University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009 (Australia); School of Mathematics and Physics, University of Queensland, St. Lucia, Queensland 4072 (Australia)

2010-09-01

329

The time of day differently influences fatigue and locomotor activity: Is body temperature a key factor?  

PubMed

The aim of this study was to verify the possible interactions between exercise capacity and spontaneous locomotor activity (SLA) during the oscillation of core body temperature (Tb) that occurs during the light/dark cycle. Wistar rats (n=11) were kept at an animal facility under a light/dark cycle of 14/10h at an ambient temperature of 23°C and water and food ad libitum. Initially, in order to characterize the daily oscillation in SLA and Tb of the rats, these parameters were continuously recorded for 24h using an implantable telemetric sensor (G2 E-Mitter). The animals were randomly assigned to two progressive exercise test protocols until fatigue during the beginning of light and dark-phases. Fatigue was defined as the moment rats could not keep pace with the treadmill. We assessed the time to fatigue, workload and Tb changes induced by exercise. Each test was separated by 3days. Our results showed that exercise capacity and heat storage were higher during the light-phase (p<0.05). In contrast, we observed that both SLA and Tb were higher during the dark-phase (p<0.01). Notably, the correlation analysis between the amount of SLA and the running capacity observed at each phase of the daily cycle revealed that, regardless of the time of the day, both types of locomotor physical activity have an important inherent component (r=0.864 and r=0.784, respectively, p<0.01) without a direct relationship between them. This finding provides further support for the existence of specific control mechanisms for each type of physical activity. In conclusion, our data indicate that the relationship between the body temperature and different types of physical activity might be affected by the light/dark cycle. These results mean that, although exercise performance and spontaneous locomotor activity are not directly associated, both are strongly influenced by daily cycles of light and dark. PMID:25479573

Machado, Frederico Sander Mansur; Rodovalho, Gisele Vieira; Coimbra, Cândido Celso

2015-03-01

330

Factors governing the structural phase transition temperatures of doped La sub 2 CuO sub 4 systems  

SciTech Connect

The authors examined the doping dependence of Ishibashi's free energy function for La{sub 2{minus}x}Ba{sub x}CuO{sub 4}, which describes the successive HTT {yields} LTO {yields} LTT phase transitions of this doped La{sub 2}CuO{sub 4} system, in terms of the tolerance factor and the local steric pressure effect of the dopant. On the basis of these microscopic considerations, they explained the general trends in the doping dependence of the HTT {yields} LTO and the LTO {yields} LTT transition temperatures in other doped La{sub 2}CuO{sub 4} systems.

Myunghwan Whangbo (North Carolina State Univ., Raleigh (United States))

1992-04-01

331

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

NASA Technical Reports Server (NTRS)

Pathophysiological conditions resulting from prolonged exposure to zero gravity, cabin constraint, altered ambient environment, whether it be noise, vibrations, high temperatures, or combinations of such factors, are studied in laboratory animals and applied to manned space flight. Results and plans for further study are presented. Specific topics covered include: thermoregulation and its role in reflecting stress and adaptation to the gravity free environment and cabin confinement with its altered circadian forcings; renal function and its measurement in electrolyte distribution and blood flow dynamics; gastronintestinal function and an assessment of altered absorptive capacity in the intestinal mucosa; and catecholamine metabolism in terms of distribution and turnover rates in specific tissues.

Musacchia, X. J.

1974-01-01

332

Time and temperature factors in reconstituting sorghum grain for beef cattle  

E-print Network

whole, dry sorghum grain to about 28 percent moisture with cold (60' F) or warm (120' F) water, followed by air-tight storage for 10 or 20 days and grinding just prior to feeding, increased gain 23 percent and decreased dry matter re- quired per... pound of gain 21 percent as compared with ground dry grain when fed to 490 pound heifers for 84 days during the winter. Neither water temperature nor storage time significantly altered the effect of reconstitution. These results indicate...

Bowers, Edwin J

1970-01-01

333

Conductivity Cell Thermal Inertia Correction Revisited  

NASA Astrophysics Data System (ADS)

Salinity measurements made with a CTD (conductivity-temperature-depth instrument) rely on accurate estimation of water temperature within their conductivity cell. Lueck (1990) developed a theoretical framework for heat transfer between the cell body and water passing through it. Based on this model, Lueck and Picklo (1990) introduced the practice of correcting for cell thermal inertia by filtering a temperature time series using two parameters, an amplitude ? and a decay time constant ?, a practice now widely used. Typically these two parameters are chosen for a given cell configuration and internal flushing speed by a statistical method applied to a particular data set. Here, thermal inertia correction theory has been extended to apply to flow speeds spanning well over an order of magnitude, both within and outside a conductivity cell, to provide predictions of ? and ? from cell geometry and composition. The extended model enables thermal inertia correction for the variable flows encountered by conductivity cells on autonomous gliders and floats, as well as tethered platforms. The length scale formed as the product of cell encounter speed of isotherms, ?, and ? can be used to gauge the size of the temperature correction for a given thermal stratification. For cells flushed by dynamic pressure variation induced by platform motion, this length varies by less than a factor of 2 over more than a decade of speed variation. The magnitude of correction for free-flow flushed sensors is comparable to that of pumped cells, but at an order of magnitude in energy savings. Flow conditions around a cell's exterior are found to be of comparable importance to thermal inertia response as flushing speed. Simplification of cell thermal response to a single normal mode is most valid at slow speed. Error in thermal inertia estimation arises from both neglect of higher modes and numerical discretization of the correction scheme, both of which can be easily quantified. Consideration of thermal inertia correction enables assessment of various CTD sampling schemes. Spot sampling by pumping a cell intermittently provides particular challenges, and may lead to biases in inferred salinity that are comparable to climate signals reported from profiling float arrays.

Eriksen, C. C.

2012-12-01

334

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

PubMed

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

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

2012-01-01

335

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

336

Atmospheric corrections for TIMS estimated emittance  

NASA Technical Reports Server (NTRS)

The estimated temperature of the average of 500 lines of Thermal Infrared Multispectral Scanner (TIMS) data of the Pacific Ocean, from flight line 94, collected on 30 Sep. 1988, at 1931 GMT is shown. With no atmospheric corrections, estimated temperature decreases away from nadir (the center of the scan line). A LOWTRAN modeled correction, using local radiosonde data and instrument scan angle information, results in reversed limb darkening effects for most bands, and does not adequately correct all bands to the same temperature. The atmosphere tends to re-radiate energy at the wavelengths at which it most absorbs, and thus the overall difference between corrected and uncorrected temperatures is approximately 40 C, despite the average LOWTRAN calculated transmittance of only 60 percent between 8.1 and 11.6 microns. An alternative approach to atmospheric correction is a black body normalization. This is done by calculating a normalization factor for each pixel position and wavelength, which when applied results in a single calculated temperature, as would be expected for a gray body with near uniform emittance. The black body adjustment is based on the atmospheric conditions over the sea. The ground elevation profile along the remaining 3520 scan lines (approximately 10 km) of flight line 94, up the slopes of Kilauea, determined from aircraft pressure and laser altimeter data is shown. This flight line includes a large amount of vegetation that is clearly discernible on the radiance image, being much cooler than the surrounding rocks. For each of the 3520 scan lines, pixels were classified as vegetation or 'other'. A moving average of 51 lines was applied to the composite vegetation emittance for each scan line, to reduce noise. Assuming vegetation to be like water, and to act as gray body with an emittance of 0.986 across the spectrum, it is shown that that the LOWTRAN induced artifacts are severe, and other than for the 0.9.9 micron channel, not significantly different from applying no corrections at all. As expected, with increasing elevation atmospheric effects are slightly reduced, because moisture tends to be concentrated in the lowermost part of the atmosphere. The black body adjustment is highly robust, and even at elevations nearly 600 meters above the sea, remains an alternative procedure for use in calculating emittance.

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

1992-01-01

337

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

NASA Astrophysics Data System (ADS)

Trace gas emissions from the soil surface are often underestimated due to poor understanding of the factors regulating fluxes under extreme conditions when moisture can be highly variable. In particular, dynamics of soil surface trace gas emissions from hot agricultural regions can be difficult to predict due to the sporadic use of flood irrigation and nitrogen fertilization. Soil surface CO2 and NOx fluxes are especially difficult to predict due to nonlinear responses to pulse water and fertilization events. Additionally, models such as Lloyd and Taylor (1994) and Yienger and Levy II (1995) are not well parameterized for soil surface CO2 and NOx flux, respectively, under excessively high temperatures. We measured soil surface CO2 and NOx flux in an agricultural field transitioning from fallow to biofuel crop production (Sorghum bicolor). Soil surface CO2 flux was measured using CO2 probes coupled with the flux-gradient method. NOx measurements were made using chambers coupled with a NOx monitor. Our field site is located at the University of California Desert Research and Extension Center in the Imperial Valley of CA. Air temperatures regularly exceed 42°C in the summer. Flood irrigation is used at the site as well as nitrogen fertilizers. Soil respiration ranged from 0-15 ?moles CO2 m-2 s-1, with strong hysteresis observed both with and without plants. Soil CO2 fluxes measured in the fallow field before the biofuel crop was planted were temperature independent and mainly regulated by soil moisture. When plants were introduced, temperature became an important predictor for soil respiration as well as canopy height. NOx fluxes were highest at intermediate soil moisture and varied significantly across an irrigation cycle. NOx emissions were temperature dependent, ranging from 3-113 ng N cm-2 hr-1. Neither CO2 nor NOx emissions showed inhibition at soil temperatures up to 55°C. Models may underestimate fluxes of CO2 and NOx from hot agricultural regions due to their inability to account for high temperature emission behavior, responses to irrigation and fertilization events, and influence of vegetation on soil surface trace gas flux.

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

2012-12-01

338

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

NASA Technical Reports Server (NTRS)

The effect of trunk cooling on the muscle contents of ATP, ADP, AMP, creatine phosphate (CrP), and creatine, as well as of glycogen, some glycolytic intermediates, pyruvate, and lactate were assessed in 11 fasted dogs exercised at 20 C on treadmill to exhaustion. Without cooling, dogs were able to run 57 min, and their rectal (Tre) and muscle (Tm) temperatures increased to 41.8 and 43.0 C, respectively. Cooling with ice packs prolonged the ability to run by 45 percent, and resulted in lower Tre (by 1.1 C) and Tm (by 1.2 C). Depletion of muscle content of total high-energy phosphates (ATP + CrP) and glycogen, and increases in contents of AMP, pyruvate, and lactate were lower in cooled dogs than in non-cooled dogs. The muscle content of lactiate correlated positively with TM. These results indicate that hypothermia accelerates glycolysis, and shifts the equilibrium between high- and low-energy phosphates in favor of the latter. The adverse effect of hypothermia on muscle metabolism may be relevant to the limitation of endurance.

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

1985-01-01

339

Temperature dependence of the Tafel slope and electrochemical barrier symmetry factor,. beta. , in electrode kinetics  

SciTech Connect

The significance of the new-established situation that the Tafel slopes, b, ( = d{eta}/d In i) for simple charge-transfer processes at electrodes are usually not represented with respect to variation with temperature, T, by the conventional relation b = RT/{beta} cpF, where {beta} is a constant-valued electrochemical charge-transfer barrier-symmetry coefficient, is examined in the light of recent comments on the problem. Clear evidence is given that b has the form b = RT({beta}sub H + T{beta}{sub s})F for proton transfer at Hg in water and various other solvents, where {beta}{sub H} and T{beta}{sub s} are enthalpic components of the overall {beta}, corresponding to experimentally observable potential-dependence of both the enthalpy and the entropy of activation, respectively. The frequent deviation from conventional behavior thus arises because the entropy of activation, as well as the energy of activation, can be potential-dependent, a situation that, until recently, has been neglected in inter-pretations of electrode-kinetic experiments. The origin of the conventional effect of potential on electrode reaction rates, through the change of electrode work function,{Phi}, with overpotential or electrode potential, V, ({Phi}{sub v} = {Phi}{sub v = O}{plus minus} eV), is examined critically in relation to the potential-dependent surface-potential component, {chi}{sub d}, in {Phi}, which can also be T-dependent.

Conway, B.E. (Dept. of Chemistry, Univ. of Ottawa, Ontario (CA)); Tessier, D.F. (Alcan International, Research Labs. Kingston, Ontario (CA)); Wilkinson, D.P. (Moli Energy Limited, Burnaby, Vancouver, British Columbia (CA))

1989-09-01

340

Global coral disease prevalence associated with sea temperature anomalies and local factors.  

PubMed

Coral diseases are taking an increasing toll on coral reef structure and biodiversity and are important indicators of declining health in the oceans. We implemented standardized coral disease surveys to pinpoint hotspots of coral disease, reveal vulnerable coral families and test hypotheses about climate drivers from 39 locations worldwide. We analyzed a 3 yr study of coral disease prevalence to identify links between disease and a range of covariates, including thermal anomalies (from satellite data), location and coral cover, using a Generalized Linear Mixed Model. Prevalence of unhealthy corals, i.e. those with signs of known diseases or with other signs of compromised health, exceeded 10% on many reefs and ranged to over 50% on some. Disease prevalence exceeded 10% on 20% of Caribbean reefs and 2.7% of Pacific reefs surveyed. Within the same coral families across oceans, prevalence of unhealthy colonies was higher and some diseases were more common at sites in the Caribbean than those in the Pacific. The effects of high disease prevalence are potentially extensive given that the most affected coral families, the acroporids, faviids and siderastreids, are among the major reef-builders at these sites. The poritids and agaricids stood out in the Caribbean as being the most resistant to disease, even though these families were abundant in our surveys. Regional warm temperature anomalies were strongly correlated with high disease prevalence. The levels of disease reported here will provide a much-needed local reference point against which to compare future change. PMID:22968792

Ruiz-Moreno, Diego; Willis, Bette L; Page, A Cathie; Weil, Ernesto; Cróquer, Aldo; Vargas-Angel, Bernardo; Jordan-Garza, Adán Guillermo; Jordán-Dahlgren, Eric; Raymundo, Laurie; Harvell, C Drew

2012-09-12

341

Role of electronic correlation in high-low temperature phase transition of hexagonal nickel sulfide: a comparative density functional theory study with and without correction for on-site Coulomb interaction.  

PubMed

The structural, electronic, magnetic, and elastic properties of hexagonal nickel sulfide (NiS) have been investigated comparatively by Density Functional theory (DFT) and DFT plus correction for on-site Coulomb interaction (DFT+U), in which two different exchange correlation functionals local density approximations (LDA) and general gradient approximations (GGA) in the form of Perdew-Burke-Ernzerhof (PBE) are used. Our results indicate LDA and PBE methods predict hexagonal NiS to be a paramagnetic metal whereas LDA(PBE)+U calculations with reasonable on-site Coulomb interaction energy give the antiferromagnetic insulating state of low temperature hexagonal NiS successfully. Meanwhile, compared with LDA(PBE) results, LDA(PBE)+U methods give larger lattice parameters, crystal volume, and shear constant c44, consistent with the experimental picture during high-low temperature phase transition of hexagonal NiS, in which an increase of the shear constant c44 and lattice parameters were found in the low-temperature antiferromagnetic phase. The present DFT and DFT+U calculations provide a reasonable description for the properties of high temperature and low temperature hexagonal NiS respectively, which indicates that electronic correlation is responsible for this high-low temperature phase transition. PMID:23822260

Zhang, Wei-Bing; Li, Jie; Tang, Bi-Yu

2013-06-28

342

Role of electronic correlation in high-low temperature phase transition of hexagonal nickel sulfide: A comparative density functional theory study with and without correction for on-site Coulomb interaction  

NASA Astrophysics Data System (ADS)

The structural, electronic, magnetic, and elastic properties of hexagonal nickel sulfide (NiS) have been investigated comparatively by Density Functional theory (DFT) and DFT plus correction for on-site Coulomb interaction (DFT+U), in which two different exchange correlation functionals local density approximations (LDA) and general gradient approximations (GGA) in the form of Perdew-Burke-Ernzerhof (PBE) are used. Our results indicate LDA and PBE methods predict hexagonal NiS to be a paramagnetic metal whereas LDA(PBE)+U calculations with reasonable on-site Coulomb interaction energy give the antiferromagnetic insulating state of low temperature hexagonal NiS successfully. Meanwhile, compared with LDA(PBE) results, LDA(PBE)+U methods give larger lattice parameters, crystal volume, and shear constant c44, consistent with the experimental picture during high-low temperature phase transition of hexagonal NiS, in which an increase of the shear constant c44 and lattice parameters were found in the low-temperature antiferromagnetic phase. The present DFT and DFT+U calculations provide a reasonable description for the properties of high temperature and low temperature hexagonal NiS respectively, which indicates that electronic correlation is responsible for this high-low temperature phase transition.

Zhang, Wei-Bing; Li, Jie; Tang, Bi-Yu

2013-06-01

343

Roles of the CBF2 and ZAT12 transcription factors in configuring the low temperature transcriptome of Arabidopsis.  

PubMed

Summary The CBF cold response pathway has a prominent role in cold acclimation. The pathway includes action of three transcription factors, CBF1, 2 and 3 (also known as DREB1b, c and a, respectively), that are rapidly induced in response to low temperature followed by expression of the CBF-targeted genes (the CBF regulon) that act in concert to increase plant-freezing tolerance. The results of transcriptome profiling and mutagenesis experiments, however, indicate that additional cold response pathways exist and may have important roles in life at low temperature. To further understand the roles that the CBF proteins play in configuring the low temperature transcriptome and to identify additional transcription factors with roles in cold acclimation, we used the Affymetrix GeneChip containing probe sets for approximately 24,000 Arabidopsis genes to define a core set of cold-responsive genes and to determine which genes were targets of CBF2 and 6 other transcription factors that appeared to be coordinately regulated with CBF2. A total of 514 genes were placed in the core set of cold-responsive genes, 302 of which were upregulated and 212 downregulated. Hierarchical clustering and bioinformatic analysis indicated that the 514 cold-responsive transcripts could be assigned to one of seven distinct expression classes and identified multiple potential novel cis-acting cold-regulatory elements. Eighty-five cold-induced genes and eight cold-repressed genes were assigned to the CBF2 regulon. An additional nine cold-induced genes and 15 cold-repressed genes were assigned to a regulon controlled by ZAT12. Of the 25 core cold-induced genes that were most highly upregulated (induced over 15-fold), 19 genes (84%) were induced by CBF2 and another two genes (8%) were regulated by both CBF2 and ZAT12. Thus, the large majority (92%) of the most highly induced genes belong to the CBF and ZAT12 regulons. Constitutive expression of ZAT12 in Arabidopsis caused a small, but reproducible, increase in freezing tolerance, indicating a role for the ZAT12 regulon in cold acclimation. In addition, ZAT12 downregulated the expression of the CBF genes indicating a role for ZAT12 in a negative regulatory circuit that dampens expression of the CBF cold response pathway. PMID:15634197

Vogel, Jonathan T; Zarka, Daniel G; Van Buskirk, Heather A; Fowler, Sarah G; Thomashow, Michael F

2005-01-01

344

Isotope effects in liquid water by infrared spectroscopy. II. Factor analysis of the temperature effect on H2O and D2O  

Microsoft Academic Search

Some 500 infrared (IR) spectra of light and heavy waters were obtained between 29 and 93 °C in order to identify the species present in liquid water. Factor analysis of these gives two species for each type of water with their IR spectra and abundance curves. Using an orthogonalization procedure, we obtained the temperature factor limits of -22 and +118

Pascal Larouche; Jean-Joseph Max; Camille Chapados

2008-01-01

345

A 320fs-RMS-jitter and 300kHz-BW all-digital fractional-N PLL with self-corrected TDC and fast temperature tacking loop for WiMax\\/WLAN 11n  

Microsoft Academic Search

This paper presents a 3.9-to-5.39GHz all-digital fractional-N PLL for WiMax\\/WLAN 11n application. The ADPLL uses a self-corrected TDC to achieve meta-stable-error-free operation, wide dynamic range and high timing resolution in a small chip area. The rms jitter from 1kHz to 40MHz is 320fs at 4.51GHz while the calibrated bandwidth is 300KHz. With aid of the fast temperature tracking loop, the

Hsiang-Hui Chang; Chia-Huang Fu; Monty Chiu

2009-01-01

346

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

347

High Q-factor Sapphire Whispering Gallery Mode Microwave Resonator at Single Photon Energies and milli-Kelvin Temperatures  

E-print Network

The microwave properties of a crystalline sapphire dielectric whispering gallery mode resonator have been measured at very low excitation strength (E/hf=1) and low temperatures (T = 30 mK). The measurements were sensitive enough to observe saturation due to a highly detuned electron spin resonance, which limited the loss tangent of the material to about 2e-8 measured at 13.868 and 13.259 GHz. Small power dependent frequency shifts were also measured which correspond to an added magnetic susceptibility of order 1e-9. This work shows that quantum limited microwave resonators with Q-factors > 1e8 are possible with the implementation of a sapphire whispering gallery mode system.

Creedon, Daniel L; Farr, Warrick; Martinis, John M; Duty, Timothy L; Tobar, Michael E

2011-01-01

348

High Q-factor Sapphire Whispering Gallery Mode Microwave Resonator at Single Photon Energies and milli-Kelvin Temperatures  

E-print Network

The microwave properties of a crystalline sapphire dielectric whispering gallery mode resonator have been measured at very low excitation strength (E/hf=1) and low temperatures (T = 30 mK). The measurements were sensitive enough to observe saturation due to a highly detuned electron spin resonance, which limited the loss tangent of the material to about 2e-8 measured at 13.868 and 13.259 GHz. Small power dependent frequency shifts were also measured which correspond to an added magnetic susceptibility of order 1e-9. This work shows that quantum limited microwave resonators with Q-factors > 1e8 are possible with the implementation of a sapphire whispering gallery mode system.

Daniel L. Creedon; Yarema Reshitnyk; Warrick Farr; John M. Martinis; Timothy L. Duty; Michael E. Tobar

2011-04-01

349

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

350

Measurements of skin temperature responses to cold exposure of foot and face in healthy individuals: variability and influencing factors.  

PubMed

Skin vasomotor responses to cold exposure (CE) have been measured widely and shown to be abnormal in some clinical conditions. Among other methods, monitoring of skin temperature (Tsk) changes has been applied for those purposes. We investigated such changes simultaneously in different skin areas of healthy young men during foot and facial CE. Tsk was measured using infrared thermography in the big toe and dorsum of the left foot and with a contact thermode in the fingertip. The relationship of Tsk responses within individuals and factors influencing them were examined using mixed model analysis. Tsk changes varied greatly between sessions, measured areas and individuals. Foot CE that was painful produced both stronger central circulatory and Tsk responses than facial CE. Tsk changes were prominent in the fingertip, moderate in the toe and weak or absent in the dorsal foot. The Tsk changes were related to the baseline levels and changes of blood pressure, heart rate, the baseline Tsk values and stimulus intensity. However, despite the different cold stimuli and measurement techniques, an intra-individual correlation of the Tsk responses was good. In the foot, the big toe area is applicable for studies of Tsk reactions when warm, and the modified Tsk gradient helps to evaluate the level of peripheral vasoconstriction. The cold-induced Tsk changes may be informative in the studies of the cutaneous vasoregulation but the individual character of the cold stress reactivity and numerous confusing factors should be considered when drawing conclusions on the basis of the recorded results. PMID:21672139

Zaproudina, Nina; Lipponen, Jukka A; Eskelinen, Perttu; Tarvainen, Mika P; Karjalainen, Pasi A; Närhi, Matti

2011-07-01

351

Curvature-correction-based time-domain CMOS smart temperature sensor with an inaccuracy of -0.8 °C-1.2 °C after one-point calibration from -40 °C to 120 °C  

NASA Astrophysics Data System (ADS)

This paper proposes a time-domain CMOS smart temperature sensor featuring on-chip curvature correction and one-point calibration support for thermal management systems. Time-domain inverter-based temperature sensors, which exhibit the advantages of low power and low cost, have been proposed for on-chip thermal monitoring. However, the curvature is large for the thermal transfer curve, which substantially affects the accuracy as the temperature range increases. Another problem is that the inverter is sensitive to process variations, resulting in difficulty for the sensors to achieve an acceptable accuracy for one-point calibration. To overcome these two problems, a temperature-dependent oscillator with curvature correction is proposed to increase the linearity of the oscillatory width, thereby resolving the drawback caused by a costly off-chip second-order master curve fitting. For one-point calibration support, an adjustable-gain time amplifier was adopted to eliminate the effect of process variations, with the assistance of a calibration circuit. The proposed circuit occupied a small area of 0.073 mm2 and was fabricated in a TSMC CMOS 0.35-?m 2P4M digital process. The linearization of the oscillator and the effect cancellation of process variations enabled the sensor, which featured a fixed resolution of 0.049 °C/LSB, to achieve an optimal inaccuracy of -0.8 °C to 1.2 °C after one-point calibration of 12 test chips from -40 °C to 120 °C. The power consumption was 35 ?W at a sample rate of 10 samples/s.

Chen, Chun-Chi; Lin, Shih-Hao; Lin, Yi

2014-06-01

352

Curvature-correction-based time-domain CMOS smart temperature sensor with an inaccuracy of -0.8?°C-1.2?°C after one-point calibration from -40?°C to 120?°C.  

PubMed

This paper proposes a time-domain CMOS smart temperature sensor featuring on-chip curvature correction and one-point calibration support for thermal management systems. Time-domain inverter-based temperature sensors, which exhibit the advantages of low power and low cost, have been proposed for on-chip thermal monitoring. However, the curvature is large for the thermal transfer curve, which substantially affects the accuracy as the temperature range increases. Another problem is that the inverter is sensitive to process variations, resulting in difficulty for the sensors to achieve an acceptable accuracy for one-point calibration. To overcome these two problems, a temperature-dependent oscillator with curvature correction is proposed to increase the linearity of the oscillatory width, thereby resolving the drawback caused by a costly off-chip second-order master curve fitting. For one-point calibration support, an adjustable-gain time amplifier was adopted to eliminate the effect of process variations, with the assistance of a calibration circuit. The proposed circuit occupied a small area of 0.073 mm(2) and was fabricated in a TSMC CMOS 0.35-?m 2P4M digital process. The linearization of the oscillator and the effect cancellation of process variations enabled the sensor, which featured a fixed resolution of 0.049?°C/LSB, to achieve an optimal inaccuracy of -0.8?°C to 1.2?°C after one-point calibration of 12 test chips from -40?°C to 120?°C. The power consumption was 35 ?W at a sample rate of 10 samples/s. PMID:24985845

Chen, Chun-Chi; Lin, Shih-Hao; Lin, Yi

2014-06-01

353

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

Microsoft Academic Search

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

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

2002-01-01

354

Positive matrix factorization of a 32-month series of daily PM2.5 speciation data with incorporation of temperature stratification.  

PubMed

This study presents source apportionment results for PM2.5 from applying positive matrix factorization (PMF) to a 32-month series of daily PM2.5 compositional data from Denver, CO, including concentrations of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solution was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutions with those from the base case solution. These eight factors were identified as inorganic ion, n-alkane, EC/sterane, light n-alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd n-alkane. The inorganic ion factor dominated the reconstructed PM2.5 mass (sulfate + nitrate + EC + OC) in cold periods (daily average temperature < 10 °C; 43.7% of reconstructed PM2.5 mass) whereas the summer/odd n-alkane factor dominated in hot periods (> 20 °C; 53.1%). The two factors had comparable relative contributions of 26.5% and 27.1% in warm periods with temperatures between 10 °C and 20 °C. Each of the seven factors resolved in a previous study (Dutton et al., 2010b) using a 1-year data set from the same location matches one factor from the current work based on comparing factor profiles. Six out of the seven matched pairs of factors are linked to similar source classes as suggested by the strong correlations between factor contributions (r = 0.89 - 0.98). Temperature-stratified source apportionment was conducted for three subsets of the data in the current study, corresponding to the cold, warm and hot periods mentioned above. The cold period (7-factor) solution exhibited a similar distribution of reconstructed PM2.5 mass as the full data set solution. The factor contributions of the warm period (7-factor) solution were well correlated with those from the full data set solution (r = 0.76 - 0.99). However, the reconstructed PM2.5 mass was distributed more to inorganic ion, n-alkane and medium alkane/alkanoic acid factors in the warm period solution than in the full data set solution. For the hot period (6-factor) solution, PM2.5 mass distribution was quite different from that of the full data set solution, as illustrated by regression slopes as low as 0.2 and as high as 4.8 of each matched pair of factors across the two solutions. PMID:25214809

Xie, Mingjie; Piedrahita, Ricardo; Dutton, Steven J; Milford, Jana B; Hemann, Joshua G; Peel, Jennifer L; Miller, Shelly L; Kim, Sun-Young; Vedal, Sverre; Sheppard, Lianne; Hannigan, Michael P

2013-02-01

355

Positive matrix factorization of a 32-month series of daily PM2.5 speciation data with incorporation of temperature stratification  

NASA Astrophysics Data System (ADS)

This study presents source apportionment results for PM2.5 from applying positive matrix factorization (PMF) to a 32-month series of daily PM2.5 compositional data from Denver, CO, including concentrations of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solution was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutions with those from the base case solution. These eight factors were identified as inorganic ion, n-alkane, EC/sterane, light n-alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd n-alkane. The inorganic ion factor dominated the reconstructed PM2.5 mass (sulfate + nitrate + EC + OC) in cold periods (daily average temperature <10 °C; 43.7% of reconstructed PM2.5 mass) whereas the summer/odd n-alkane factor dominated in hot periods (>20 °C; 53.1%). The two factors had comparable relative contributions of 26.5% and 27.1% in warm periods with temperatures between 10 °C and 20 °C. Each of the seven factors resolved in a previous study (Dutton et al., 2010b) using a 1-year data set from the same location matches one factor from the current work based on comparing factor profiles. Six out of the seven matched pairs of factors are linked to similar source classes as suggested by the strong correlations between factor contributions (r = 0.89-0.98). Temperature-stratified source apportionment was conducted for three subsets of the data in the current study, corresponding to the cold, warm and hot periods mentioned above. The cold period (7-factor) solution exhibited a similar distribution of reconstructed PM2.5 mass as the full data set solution. The factor contributions of the warm period (7-factor) solution were well correlated with those from the full data set solution (r = 0.76-0.99). However, the reconstructed PM2.5 mass was distributed more to inorganic ion, n-alkane and medium alkane/alkanoic acid factors in the warm period solution than in the full data set solution. For the hot period (6-factor) solution, PM2.5 mass distribution was quite different from that of the full data set solution, as illustrated by regression slopes as low as 0.2 and as high as 4.8 of each matched pair of factors across the two solutions.

Xie, Mingjie; Piedrahita, Ricardo; Dutton, Steven J.; Milford, Jana B.; Hemann, Joshua G.; Peel, Jennifer L.; Miller, Shelly L.; Kim, Sun-Young; Vedal, Sverre; Sheppard, Lianne; Hannigan, Michael P.

2013-02-01

356

Positive matrix factorization of a 32-month series of daily PM2.5 speciation data with incorporation of temperature stratification  

PubMed Central

This study presents source apportionment results for PM2.5 from applying positive matrix factorization (PMF) to a 32-month series of daily PM2.5 compositional data from Denver, CO, including concentrations of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solution was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutions with those from the base case solution. These eight factors were identified as inorganic ion, n-alkane, EC/sterane, light n-alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd n-alkane. The inorganic ion factor dominated the reconstructed PM2.5 mass (sulfate + nitrate + EC + OC) in cold periods (daily average temperature < 10 °C; 43.7% of reconstructed PM2.5 mass) whereas the summer/odd n-alkane factor dominated in hot periods (> 20 °C; 53.1%). The two factors had comparable relative contributions of 26.5% and 27.1% in warm periods with temperatures between 10 °C and 20 °C. Each of the seven factors resolved in a previous study (Dutton et al., 2010b) using a 1-year data set from the same location matches one factor from the current work based on comparing factor profiles. Six out of the seven matched pairs of factors are linked to similar source classes as suggested by the strong correlations between factor contributions (r = 0.89 ? 0.98). Temperature-stratified source apportionment was conducted for three subsets of the data in the current study, corresponding to the cold, warm and hot periods mentioned above. The cold period (7-factor) solution exhibited a similar distribution of reconstructed PM2.5 mass as the full data set solution. The factor contributions of the warm period (7-factor) solution were well correlated with those from the full data set solution (r = 0.76 ? 0.99). However, the reconstructed PM2.5 mass was distributed more to inorganic ion, n-alkane and medium alkane/alkanoic acid factors in the warm period solution than in the full data set solution. For the hot period (6-factor) solution, PM2.5 mass distribution was quite different from that of the full data set solution, as illustrated by regression slopes as low as 0.2 and as high as 4.8 of each matched pair of factors across the two solutions. PMID:25214809

Xie, Mingjie; Piedrahita, Ricardo; Dutton, Steven J.; Milford, Jana B.; Hemann, Joshua G.; Peel, Jennifer L.; Miller, Shelly L.; Kim, Sun-Young; Vedal, Sverre; Sheppard, Lianne; Hannigan, Michael P.

2014-01-01

357

Factors Influencing Oral Corrective Feedback Provision in the Spanish Foreign Language Classroom: Investigating Instructor Native/Nonnative Speaker Status, SLA Education, & Teaching Experience  

ERIC Educational Resources Information Center

The role of interactional feedback has been a critical area of second language acquisition (SLA) research for decades and while findings suggest interactional feedback can facilitate SLA, the extent of its influence can vary depending on a number of factors, including the native language of those involved in communication. Although studies have…

Gurzynski-Weiss, Laura

2010-01-01

358

Isotope effects in liquid water by infrared spectroscopy. II. Factor analysis of the temperature effect on H2O and D2O  

NASA Astrophysics Data System (ADS)

Some 500 infrared (IR) spectra of light and heavy waters were obtained between 29 and 93 °C in order to identify the species present in liquid water. Factor analysis of these gives two species for each type of water with their IR spectra and abundance curves. Using an orthogonalization procedure, we obtained the temperature factor limits of -22 and +118 °C (+/-5 °C) that we coined cold and hot factors, respectively. Within experimental error, these limits are the same for light and heavy waters. The spectra of the orthogonalized factors presented show a decrease of the OH (OD) stretch band integrated intensities of almost 36% from the cold to the hot factors. No ``free'' OH (OD) group is present or formed in the temperature ramp. This indicates that all water molecules in the bulk are made of an oxygen atom surrounded with four hydrogen atoms, two covalently bonded, and two hydrogen bonded. This is consistent with the previous study of mixtures of H2O and D2O [part I: J.-J. Max and C. Chapados, J. Chem. Phys. 116, 4626 (2002)]. To maintain the ordinary liquid within the limits of 0 and 100 °C at atmospheric pressure, a fraction of the cold and hot factors are necessary. With the spectra of the cold and hot factors and the abundance curves, one can generate the spectrum at any temperature between -22 and +118 °C of light and heavy liquid waters.

Larouche, Pascal; Max, Jean-Joseph; Chapados, Camille

2008-08-01

359

Radiosondes Corrected for Inaccuracy in RH Measurements  

SciTech Connect

Corrections for inaccuracy in Vaisala radiosonde RH measurements have been applied to ARM SGP radiosonde soundings. The magnitude of the corrections can vary considerably between soundings. The radiosonde measurement accuracy, and therefore the correction magnitude, is a function of atmospheric conditions, mainly T, RH, and dRH/dt (humidity gradient). The corrections are also very sensitive to the RH sensor type, and there are 3 Vaisala sensor types represented in this dataset (RS80-H, RS90, and RS92). Depending on the sensor type and the radiosonde production date, one or more of the following three corrections were applied to the RH data: Temperature-Dependence correction (TD), Contamination-Dry Bias correction (C), Time Lag correction (TL). The estimated absolute accuracy of NIGHTTIME corrected and uncorrected Vaisala RH measurements, as determined by comparison to simultaneous reference-quality measurements from Holger Voemel's (CU/CIRES) cryogenic frostpoint hygrometer (CFH), is given by Miloshevich et al. (2006).

Miloshevich, Larry

2008-01-15

360

Radiosondes Corrected for Inaccuracy in RH Measurements  

DOE Data Explorer

Corrections for inaccuracy in Vaisala radiosonde RH measurements have been applied to ARM SGP radiosonde soundings. The magnitude of the corrections can vary considerably between soundings. The radiosonde measurement accuracy, and therefore the correction magnitude, is a function of atmospheric conditions, mainly T, RH, and dRH/dt (humidity gradient). The corrections are also very sensitive to the RH sensor type, and there are 3 Vaisala sensor types represented in this dataset (RS80-H, RS90, and RS92). Depending on the sensor type and the radiosonde production date, one or more of the following three corrections were applied to the RH data: Temperature-Dependence correction (TD), Contamination-Dry Bias correction (C), Time Lag correction (TL). The estimated absolute accuracy of NIGHTTIME corrected and uncorrected Vaisala RH measurements, as determined by comparison to simultaneous reference-quality measurements from Holger Voemel's (CU/CIRES) cryogenic frostpoint hygrometer (CFH), is given by Miloshevich et al. (2006).

Miloshevich, Larry

361

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

362

Correctional Officers' Attitudes toward Selected Treatment Programs.  

ERIC Educational Resources Information Center

Examined the attitudes of a sample of correctional officers toward selected treatment programs. Besides a number of factors which correlated with positive attitudes toward treatment, several factors correlated negatively, including number of years of service and a belief that the primary function of corrections is punishment. (Author)

Teske, Raymond H. C.; Williamson, Harold E.

1979-01-01

363

Identification of novel meristem factors involved in shoot regeneration through the analysis of temperature-sensitive mutants of Arabidopsis.  

PubMed

Adventitious organogenesis in plant tissue culture involves de novo formation of apical meristems and should therefore provide important information about the fundamentals of meristem gene networks. We identified novel factors required for neoformation of the shoot apical meristem (SAM) through an analysis of shoot regeneration in root initiation defective3 (rid3) and root growth defective3 (rgd3) temperature-sensitive mutants of Arabidopsis. After induction of callus to regenerate shoots, cell division soon ceased and was then reactivated locally in the surface region, resulting in formation of mounds of dense cells in which adventitious-bud SAMs were eventually constructed. The rgd3 mutation inhibited reactivation of cell division and suppressed expression of CUP-SHAPED COTYLEDON1 (CUC1), CUC2 and SHOOT MERISTEMLESS (STM). In contrast, the rid3 mutation caused excess ill-controlled cell division on the callus surface. This was intimately related to enhanced and broadened expression of CUC1. Positional cloning revealed that the RGD3 and RID3 genes encode BTAF1 (a kind of TATA-binding protein-associated factor) and an uncharacterized WD-40 repeat protein, respectively. In the early stages of shoot regeneration, RGD3 was expressed (as was CUC1) in the developing cell mounds, whereas RID3 was expressed outside the cell mounds. When RID3 was over-expressed artificially, the expression levels of CUC1 and STM were significantly reduced. Taken together, these findings show that both negative regulation by RID3 and positive regulation by RGD3 of the CUC-STM pathway participate in proper control of cell division as a prerequisite for SAM neoformation. PMID:19054368

Tamaki, Hiroaki; Konishi, Mineko; Daimon, Yasufumi; Aida, Mitsuhiro; Tasaka, Masao; Sugiyama, Munetaka

2009-03-01

364

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

365

Nonsteroidal anti-inflammatory drugs reduce the production of quorum sensing regulated virulence factors and swarm in motility in human pathogen Pseudomonas aeruginosa [corrected].  

PubMed

Antibiotics are commonly used for the treatment of microbial infections. With the widespread appearance of multi antibiotic-resistant bacteria, it is becoming increasingly more difficult to treat bacterial infections with conventional antibiotics. Thus, there is an increasing need for new strategies to cope with infectious diseases. The discovery that many pathogenic bacteria employ quorum sensing (QS) to regulate their pathogenicity and virulence factor production makes the QS system an attractive target for antimicrobial therapy. It has been suggested that inactivating the QS system of a pathogen can result in a significant decrease in virulence factor production. In this study, a variety of NSAIDs, such as diclofenac, ibufen, ketoprofen, naproxen, piroxicam were screened for their capacity to reduce the production of QS-regulated virulence factors and swarming motility in the human pathogen P. aeruginosa. Ketoprofen, diclofenac, ibufen, naproxen and piroxicam reduced the elastase production by 28-47% compared to the untreated cultures. Pyocyanin production was also inhibited by these compounds but to a lesser extent. In swarming assay plates, ketoprofen and diclofenac treated PA01 strain displayed significant reductions in swarming motility (81% and 84% respectively). These findings suggest that especially, ketoprofen and diclofenac, may prevent bacterial colonization, and thereby reducing biofilm formation, by interfering with QS-controlled swarming motility of P. aeruginosa and combinatory chemotherapy with both conventional antibiotics and tested NSAIDs could be used for the treatment of chronic infections caused by P. aeruginosa and other clinically important pathogens which regulate their pathogenicity via QS. PMID:23599038

Ulusoy, S; Bosgelmez-Tinaz, G

2013-08-01

366

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

PubMed Central

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

Gómez-Cuadrado, A; Martín, M; Noël, M; Ruiz-Carrillo, A

1995-01-01

367

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

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

368

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

SciTech Connect

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

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

2011-04-01

369

Fermions Tunnelling with Quantum Gravity Correction  

NASA Astrophysics Data System (ADS)

Based on the generalized uncertainty principle (GUP), we investigate the correction of quantum gravity to Hawking radiation of black hole by utilizing the tunnelling method. The result tells us that the quantum gravity correction retards the evaporation of black hole. Using the corrected covariant Dirac equation in curved spacetime, we study the tunnelling process of fermions in Schwarzschild spacetime and obtain the corrected Hawking temperature. It turns out that the correction depends not only on the mass of black hole but also on the mass of emitted fermions. In our calculation, the quantum gravity correction slows down the increase of Hawking temperature during the radiation explicitly. This correction leads to the remnants of black hole and avoids the evaporation singularity.

Liu, Zhen-Yu; Ren, Ji-Rong

2014-12-01

370

Limitations of ZAF correction factors in the determination of calcium/phosphorus ratios: Important forensic science considerations relevant to the analysis of bone fragments using scanning electron microscopy and energy-dispersive x-ray microanalysis  

SciTech Connect

A series of calcium phosphate standards having calcium/phosphorus (Ca/P) molar ratios of 0.50, 1.00, 1.50, and 1.67, respectively, was prepared for bulk specimen analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDXA). The standards were mounted on carbon planchettes as either pure crystals or crystals embedded in epoxy resin. Ten different samples of each embedded and non-embedded standard were analyzed in a JEOL 100 CX electron microscope interfaced with a Kevex 8000 EDXA system using a lithium-drifted silicon detector and a multichannel analyzer. The Ca/P ratios were determined by calculating both net peak intensities without matrix corrections and atomic kappa-ratios using the MAGIC V computer program with ZAF correction factors for quantitative analysis. There was such extensive absorption of phosphorus X-rays in standards embedded in an epoxy matrix that the observed Ca/P ratios were statistically compatible with four different standards ranging in theoretical Ca/P ratios from 1.0 to 1.67. Although the non-embedded crystals showed a greater separation in the Ca/P ratios, both methods of preparation produced serious flaws in analysis. Direct application of the discovery of this caveat to the identification of suspected bone fragments for forensic science purposes is discussed.

Payne, C.M.; Cromey, D.W. (Univ. of Arizona, Tucson (USA))

1990-05-01

371

Limitations of ZAF correction factors in the determination of calcium/phosphorus ratios: important forensic science considerations relevant to the analysis of bone fragments using scanning electron microscopy and energy-dispersive x-ray microanalysis.  

PubMed

A series of calcium phosphate standards having calcium/phosphorus (Ca/P) molar ratios of 0.50, 1.00, 1.50, and 1.67, respectively, was prepared for bulk specimen analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDXA). The standards were mounted on carbon planchettes as either pure crystals or crystals embedded in epoxy resin. Ten different samples of each embedded and non-embedded standard were analyzed in a JEOL 100 CX electron microscope interfaced with a Kevex 8000 EDXA system using a lithium-drifted silicon detector and a multichannel analyzer. The Ca/P ratios were determined by calculating both net peak intensities without matrix corrections and atomic kappa-ratios using the MAGIC V computer program with ZAF correction factors for quantitative analysis. There was such extensive absorption of phosphorus X-rays in standards embedded in an epoxy matrix that the observed Ca/P ratios were statistically compatible with four different standards ranging in theoretical Ca/P ratios from 1.0 to 1.67. Although the non-embedded crystals showed a greater separation in the Ca/P ratios, both methods of preparation produced serious flaws in analysis. Direct application of the discovery of this caveat to the identification of suspected bone fragments for forensic science purposes is discussed. PMID:2348174

Payne, C M; Cromey, D W

1990-05-01

372

Quasar Spectrum Classification with PCA - II: Introduction of Five Classes, Artificial Quasar Spectrum, the Mean Flux Correction Factor dF,and the Identification of Emission Lines in the Ly alpha Forest  

E-print Network

We investigate the variety in quasar UV spectra (1020-1600A) with emphasis on the weak emission lines in the Ly alpha forest region using principal component analysis (PCA). This paper is a continuation of Suzuki et al. (2005, Paper I), but with a different approach. We use 50 smooth continuum fitted quasar spectra (0.14 can be related to that is measured by using power-law continuum extrapolation: = dF. The correction factor dF ranges from 0.84 to 1.05 with a mean of 0.947 and a standard deviation of 0.031 for our 50 quasars. This result means that we miss 5.3% of flux on average and we show that there are cases where we would miss 16% of flux using a power-law extrapolation.

Nao Suzuki

2005-03-10

373

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

PubMed Central

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

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

2014-01-01

374

Chironomus tentans-Repressor Splicing Factor Represses SR Protein Function Locally on Pre-mRNA Exons and Is Displaced at Correct Splice Sites  

PubMed Central

Chironomus tentans-repressor splicing factor (Ct-RSF) represses the activation of splicing by SR proteins in vitro. Ct-RSF colocalizes with the Ser-Arg-rich (SR) protein hrp45 in interchromatin granule clusters and coimmunoprecipitates with hrp45 in nuclear extracts. Ct-RSF and hrp45 can also interact directly in vitro. Ct-RSF and hrp45 are recruited together to transcribing genes and associate with growing pre-mRNAs. Ct-RSF and hrp45 colocalize at a large number of gene loci. Injection of anti-Ct-RSF antibodies into nuclei of living cells blocks association of both Ct-RSF and hrp45 with the growing pre-mRNA, whereas binding of U2 small nuclear ribonucleoprotein particle (snRNP) to the pre-mRNA is unaffected. On the intron-rich Balbiani ring (BR) 3 pre-mRNA, hrp45 as well as U1 and U2 snRNPs bind extensively, whereas relatively little Ct-RSF is present. In contrast, the BR1 and BR2 pre-mRNAs, dominated by exon sequences, bind relatively much Ct-RSF compared with hrp45 and snRNPs. Our data suggest that Ct-RSF represses SR protein function at exons and that the assembly of spliceosomes at authentic splice sites displaces Ct-RSF locally. PMID:16236800

Björk, Petra; Wetterberg-Strandh, Ingela; Baurén, Göran; Wieslander, Lars

2006-01-01

375

Correction of diabetic erectile dysfunction with adipose derived stem cells modified with the vascular endothelial growth factor gene in a rodent diabetic model.  

PubMed

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

Liu, Guihua; Sun, Xiangzhou; Bian, Jun; Wu, Rongpei; Guan, Xuan; Ouyang, Bin; Huang, Yanping; Xiao, Haipeng; Luo, Daosheng; Atala, Anthony; Zhang, Yuanyuan; Deng, Chunhua

2013-01-01

376

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

PubMed Central

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

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

2013-01-01

377

Direct comparison of the temperature dependence of the response functions measured by light scattering and optical Kerr effect spectroscopy  

Microsoft Academic Search

The frequency response functions of liquid carbon disulfide have been measured under various temperatures by two independent experiments of light scattering and ultrafast optical Kerr effect spectroscopy. The temperature dependence has been compared quantitatively after correcting the appropriate temperature-dependent factors. It is found that the response functions obtained by these methods agree quite well with each other, which enables us

J. Watanabe; M. Tohji; E. Ohtsuka; Y. Miyake; S. Kinoshita

2004-01-01

378

A 1-V piecewise curvature-corrected CMOS bandgap reference  

Microsoft Academic Search

A 1-V piecewise curvature-corrected CMOS bandgap reference (BGR) is proposed. It features in utilizing piecewise corrected current to a conventional first-order current-mode BGR. The corrected current is zero, exponential with temperature and proportional to the squared temperature in the lower, middle and upper temperature range (TR). Simulated results indicate that proposed BGR achieves temperature coefficient (TC) of 1.18ppm\\/°C in the

Jing-hu Li; Yu-nan Fu; Yong-sheng Wang

2008-01-01

379

Cold-season temperature in the Swiss Alps from AD 1100-1500; trends, intra-annual variability and forcing factors  

NASA Astrophysics Data System (ADS)

To fully understand past climatic changes and their forcing factors, detailed reconstructions of past summer and winter temperatures are required. Winter temperature reconstructions are scarce, however, because most biological proxies are biased towards the growing season. This study presents a detailed reconstruction of winter temperatures based on Chrysophyte stomatocysts, silicious scales formed by so-called 'golden algae'. Previous studies (Kamenik and Schmidt, 2005; Pla and Catalan, 2005) have demonstrated the sensitivity of these algae to cold-season temperatures. Chrysophyte stomatocyst analysis was carried out on varved sediments from Lake Silvaplana (1791 m a.s.l.) at annual to near-annual resolution for two periods; AD 1100-1500 and AD 1870-2004. For both periods the reference date 'date of spring mixing' (Smix) was reconstructed using a transfer function developed for the Austrian Alps (Kamenik and Schmidt, 2005). In the Austrian Alps, Smix was primarily driven by air temperature in the cold season. The strength of stomatocysts as a proxy for winter temperature was tested by directly comparing reconstructed Smix with measured temperatures from nearby meteostation Sils Maria for the period AD 1870 - 2004. Correlation was highest (R = -0.6; p < 0.001) with mean October-April temperatures. The good agreement between reconstructed Smix and mean winter temperatures was interrupted only from AD 1925 - AD 1951, which was related to exceptionally high winter precipitation (thick snowpack) extending the ice-covered period. Strong lake eutrophication after AD 1950 only weakly affected the reconstruction of winter temperature. The winter temperature reconstruction (AD 1100-1500) shows strong interdecadal variability, superimposed on a cooling trend from around AD 1400 onwards. A direct comparison to summer temperature reconstructions based on biogenic silica and chironomid analysis from the same cores (Trachsel et al., in review; Larocque-Tobler et al., accepted manuscript) indicated strong fluctuations in intra-annual variability. A comparison to forcing factors shows that throughout the studied period, large tropical volcanic eruptions (Crowley, 2000) coincided with relatively warm winters in the study area. This is consistent with results from GCM experiments and observations of the limited number of eruptions during the much shorter instrumental period (Fischer et al., 2007). References: T. Crowley. Science 289, 270-277 (2000) E. Fischer et al. Geophys. Res. Lett. 34, L05707 (2007) C. Kamenik and R. Schmidt. Boreas 34, 477-489 (2005) I. Larocque-Tobler et al. Quat. Sci. Rev., accepted. S. Pla and J. Catalan. Clim. Dyn. 24, 263-278 (2005) M. Trachsel et al. Manuscript in review

de Jong, Rixt; Kamenik, Christian; Grosjean, Martin

2010-05-01

380

External factors involved in the regulation of synthesis of an extracellular proteinase in Bacillus megaterium: effect of temperature  

Microsoft Academic Search

We studied the effect of temperature on the production of an extracellular neutral metalloproteinase of Bacillus megaterium in a laboratory fermentor under constant aeration and pH. The optimal temperature for growth (35–38° C) was higher than that for the synthesis of proteinase during exponential growth (below 31° C). The critical biomass concentration at which the exponential growth terminated decreased with

Jaroslav Vortuba; Jarmila Pazlarova; Milada Dvorakova; Libuse Vachova; Marie Strnadova; Helena Kucerova; Vladimir Vinter; Rimma Zourabian; Jiri Chaloupka

1991-01-01

381

Cell cycle transcription factor E2F2 mediates non-stress temperature response of AtHSP70-4 in Arabidopsis.  

PubMed

AtHSP70 expression exhibits both stress and non-stress temperature response, however, the molecular mechanisms underlying these temperature signaling pathways remain elusive. Here we performed truncation and deletion assay to investigate the cis-elements within the promoter region of AtHSP70-4 (AT3G12580). And found the region between -1000 and -1100 bp from the translation initiation site (TIS) was indispensable for the non-stress temperature response of AtHSP70. Further deletion assay of several candidate motifs within this region suggested that one 'GCGCCAAA' sequence played the critical role. This motif was found as the reverse DNA-binding motif of cell cycle transcription factor E2F family. EMSA assay verified one number of Arabidopsis E2F family-E2F2 could bind to AtHSP70-4 promoter via this motif. These results indicated the temperature regulated expression of AtHSP70-4 may be mediated by cell cycle transcription factors and participate in plant acclimations to non-stress temperature changes. PMID:25451247

Zhou, Shumin; Sun, Hengji; Zheng, Bang; Li, Ruisha; Zhang, Wei

2014-12-12

382

Numerical simulation of the effect of low-temperature transformation expansion on residual stress in cold cracking test specimens of different restraint factors  

NASA Astrophysics Data System (ADS)

Ni-Cr based high-strength weld metals have been developed to reduce preheating processes. In the development process of a welding wire, the evaluation of cold cracking resistance is important. In this study, the effect of low-temperature transformation expansion on the residual stress reduction of welds with different restraint factors in cold cracking test specimens was examined by numerical simulation. The results indicated that the weld metal with low-temperature transformation expansion exhibits the effect of residual stress reduction at a high restraint factor. The reduction decreased for a low restraint factor. Even if the restraint factor changes, the distribution of the restraint factor in the Y-groove weld cracking test is different from that in the H-type restrained weld cracking test. Distributions of residual stresses at the weld root in cold cracking in the Y-groove test and the H-type test have different tendencies. Thus, the difference should be considered when conducting the cold cracking test.

Kubota, Noriyoshi; Mikami, Yoshiki; Mochizuki, Masahito; Hiraoka, Kazuo

2012-08-01

383

Effect of temperature on ultrasonic velocity in steel  

SciTech Connect

The increased mechanical integrity requirements imposed by process safety management regulations (OSHA 29 CFR 1910.119) are forcing more operators to conduct on-stream corrosion monitoring inspections. These inspections rely predominantly on the results of ultrasonic thickness (UT) measurements, which in turn are managed by using commercial software databases. UT equipment vendors such as Krautkramer Branson recommend correcting measured thickness values {minus}0.5% per 100 F, whereas ASTM E797 recommends a {minus}1% per 100 F correction for carbon steel materials. However, little technical literature exists on the topic of UT correction factors as a function of temperature. The consequence of over-correcting a UT measurement may cause premature retirement of a piece of equipment, resulting in an unnecessary outage or material outlay. Therefore, having the appropriate UT temperature correction factors available will increase the reliability of thickness data and ultimately save operators time and money. To identify the effect of temperature on straight beam (0{degree}) ultrasonic thickness values (i.e., changes in the sound velocity), experiments were conducted using carbon steel, two low-alloy steels, and 316 stainless steel materials at temperatures ranging from 70 F to 650 F. Statistical analysis of the data revealed an inverse relationship between temperature and ultrasonic velocity over the test range with a better than 97% confidence level. The change in ultrasonic velocity with temperature also varied depending on the composition of the material. Low alloy steels (i.e., AISI 4130, 4340) were less dependent on temperature than plain carbon steels, while the 316 stainless steel had a greater temperature dependence. A series of graphs, linear regression results, and correction factors are presented for plain carbon steel (C-Mn), AISI 4130 (1Cr-1/4Mo), AISI 4340 (2Ni-1Cr-1/4Mo) and 316 stainless steel (18Cr-12Ni-3Mo).

Biagiotti, S.F. Jr. [Marathon Oil Co., Littleton, CO (United States). Petroleum Technology Center

1997-12-01

384

Restudy of surface tension of QGP with one-loop correction in the mean-field potential  

NASA Astrophysics Data System (ADS)

Surface tension of quark-gluon plasma (QGP) evolution with one-loop correction in the mean-field potential is studied. First, with the correction, the stable QGP droplet size decreases. Then, the value of surface tension is found to be improved and it approaches to the lattice value of surface tension 0.24Tc3. Moreover, the ratio of the surface tension to the cube of the critical temperature is found to increase the value in comparison to earlier studies without correction factor [R. Ramanathan, K. K. Gupta, A. K. Jha and S. S. Singh, Pram. J. Phys. 68, 757 (2007)].

Singh, S. Somorendro; Gupta, K. K.; Jha, A. K.

2014-07-01

385

Influence of salinity and temperature on the physiology of Limia melanonotata (Cyprinodontiformes: Poeciliidae): A search for abiotic factors limiting insular distribution in Hispaniola  

USGS Publications Warehouse

We investigated salinity and temperature effects on routine metabolic rate (RMR), temperature tolerance (CTMax, critical thermal maximum), and salinity tolerance of Limia melanonotata, a poecliid fish that occurs in west-central inland waters of Hispaniola. Routine metabolic rate and CTMax were measured in fish acclimated to three salinities (0, 30, and 60 ppt) and temperatures (25??, 30??, and 35??C) for nine temperature-salinity combinations. Salinity and temperature did not significantly interact in their effect on RMR. For combined salinity acclimations, adjusted RMR (ANCOVA) was significantly lower at 25??C than either 30?? or 35??C. For combined temperature acclimations, mean RMR was significantly lower at 60 ppt than either 0 or 30 ppt. Salinity and temperature had a significant interactive effect on temperature tolerance. Mean CTMax was significantly higher at 30?? than 25??C at all salinities, but at 35??C was significantly higher than at 25?? or 30??C only among fish acclimated in fresh water. Fish exposed to a chronic increase in salinity experienced most mortality in a salinity range of 70-107 ppt, with females exhibiting greater salinity tolerance than males. Limia melanonotata approaches the upper extreme in salinity and temperature tolerances known for poeciliids. Our results also suggest that L. melanonotata may reduce energy expenditures at environmental extremes to tolerate harsh conditions for extended periods. Despite its curythermal and euryhaline adaptations, L. melanonotata has a relatively restricted inland range in Hispaniola and is unknown from inshore brackish or marine habitats. The present distribution of this species and congeners may be the result of a combination of factors that include historical zoogeography and ecological requirements.

Haney, D.C.; Walsh, S.J.

2003-01-01

386

LETTER TO THE EDITOR: On the factors affecting the high temperature insulator-metal transition in rare-earth manganites  

NASA Astrophysics Data System (ADS)

The measurement of resistivity (?) across a wide temperature (T) range - from 15 to 1473 K - in the rare-earth manganite series of compounds reveals a very interesting feature: the normally observed insulating pattern beyond Tc (the Curie point) undergoes a broader transition and eventually gives way to a reentrant metallic pattern around a characteristic temperature T*. Considering a model with coexisting metallic and non-metallic phases beyond Tc, it has been shown that T* marks the temperature at which the metallic volume fraction vm(T) reaches 100% as a result of progressive removal of lattice distortion at higher temperature. T* is found to be dependent on the carrier concentration as well as on the average A-site radius () for a fixed carrier concentration.

Bhattacharya, Dipten; Das, Pintu; Pandey, A.; Raychaudhuri, A. K.; Chakraborty, Amitava; Ojha, V. N.

2001-05-01

387

Factors influencing the radiative surface temperature of grey seal ( Halichoerus grypus ) pups during early and late lactation  

Microsoft Academic Search

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\\u000a r, °C) of pups were measured on the Isle of May (56°11?N, 02°33?W), southeast Scotland from 29 October to 25 November 2003.\\u000a Records were obtained from a total

D. J. McCafferty; S. Moss; K. Bennett; P. P. Pomeroy

2005-01-01

388

Nuclear correction factors from neutrino DIS  

E-print Network

Neutrino Deep Inelastic Scattering on nuclei is an essential process to constrain the strange quark parton distribution functions in the proton. The critical component on the way to using the neutrino DIS data in a proton PDF analysis is understanding the nuclear effects in parton distribution functions. We parametrize these effects by nuclear parton distribution functions and we use this framework to analyze the consistency of neutrino DIS data with other nuclear data.

K. Kovarik

2011-07-15

389

77 FR 72199 - Technical Corrections; Correction  

Federal Register 2010, 2011, 2012, 2013

...NRC) is correcting a final rule that was published in the Federal...August 6, 2012. That final rule amended the NRC regulations...citations and typographical and spelling errors, and making other edits...authority citations in the final rule. DATES: The correction...

2012-12-05

390

A dip-dependent divergence correction  

SciTech Connect

A divergence correction is conventionally applied to zero-offset data in an effort to preserved amplitude information. The conventional divergence correction compensates for the geometrical spreading of a point source in a horizontally layered medium where velocity varies with depth only. The dip-dependent divergence correction extends the conventional correction for improved amplitude processing of dipping beds. The dip-dependent divergence correction is computed by dynamic ray tracing, and applied to stacked data using a dip decomposition technique. This correction decreases amplitudes relative to the conventional correction for steep dips and late times. In a data example from the Gulf of Mexico, the conventional correction over- amplified the reflection off a salt dome flank by a factor of 1.6. High amplitudes near salt flanks are also associated with the presence of hydrocarbons. Applying the dip-dependent divergence correction ensures that ``bright spots`` are not due to over-amplification of steep dips by the conventional correction. In areas like the Gulf of Mexico, where the velocity function varies primarily with depth, and steep beds are commonplace, the dip-dependent divergence correction is an inexpensive way to improve the amplitude information in seismic images.

Fazzari, F.

1992-07-01

391

A dip-dependent divergence correction  

SciTech Connect

A divergence correction is conventionally applied to zero-offset data in an effort to preserved amplitude information. The conventional divergence correction compensates for the geometrical spreading of a point source in a horizontally layered medium where velocity varies with depth only. The dip-dependent divergence correction extends the conventional correction for improved amplitude processing of dipping beds. The dip-dependent divergence correction is computed by dynamic ray tracing, and applied to stacked data using a dip decomposition technique. This correction decreases amplitudes relative to the conventional correction for steep dips and late times. In a data example from the Gulf of Mexico, the conventional correction over- amplified the reflection off a salt dome flank by a factor of 1.6. High amplitudes near salt flanks are also associated with the presence of hydrocarbons. Applying the dip-dependent divergence correction ensures that bright spots'' are not due to over-amplification of steep dips by the conventional correction. In areas like the Gulf of Mexico, where the velocity function varies primarily with depth, and steep beds are commonplace, the dip-dependent divergence correction is an inexpensive way to improve the amplitude information in seismic images.

Fazzari, F.

1992-01-01

392

Deformation of contour and Hawking temperature  

E-print Network

It was found that, in an isotropic coordinate system, the tunneling approach brings a factor of 1/2 for the Hawking temperature of a Schwarzschild black hole. In this paper, we address this kind of problem by studying the relation between the Hawking temperature and the deformation of integral contour for the scalar and Dirac particles tunneling. We find that correct Hawking temperature can be obtained exactly as long as the integral contour deformed corresponding to the radial coordinate transform if the transformation is a non-regular or zero function at the event horizon.

Chikun Ding; Jiliang Jing

2010-01-18

393

Correcting correlation function measurements  

NASA Astrophysics Data System (ADS)

Correlation functions measured as a function of ?? ,?? have emerged as a powerful tool to study the dynamics of particle production in nuclear collisions at high energy. They are however subject, like any other observables, to instrumental effects which must be properly accounted for to extract meaningful physics results. We compare the merits of several techniques used towards measurement of these correlation functions in nuclear collisions. We discuss and distinguish the effects of finite acceptance, and detection efficiency that may vary with collision parameters such as the position of the event in the detector and the instantaneous luminosity of the beam. We focus in particular on instrumental effects which break the factorization of the particle pair detection efficiency, and describe a technique to recover the robustness of correlation observables. We finally introduce a multidimensional weight method to correct for efficiencies that vary simultaneously with particle pseudo rapidity, azimuthal angle, transverse momentum, and the collision vertex position. The method can be generalized to account for any number of "event variables" that may break the factorability of the pair efficiency.

Ravan, Shantam; Pujahari, Prabhat; Prasad, Sidharth; Pruneau, Claude A.

2014-02-01

394

Temperature and pressure effects on capacitance probe cryogenic liquid level measurement accuracy  

NASA Technical Reports Server (NTRS)

The inaccuracies of liquid nitrogen and liquid hydrogen level measurements by use of a coaxial capacitance probe were investigated as a function of fluid temperatures and pressures. Significant liquid level measurement errors were found to occur due to the changes in the fluids dielectric constants which develop over the operating temperature and pressure ranges of the cryogenic storage tanks. The level measurement inaccuracies can be reduced by using fluid dielectric correction factors based on measured fluid temperatures and pressures. The errors in the corrected liquid level measurements were estimated based on the reported calibration errors of the temperature and pressure measurement systems. Experimental liquid nitrogen (LN2) and liquid hydrogen (LH2) level measurements were obtained using the calibrated capacitance probe equations and also by the dielectric constant correction factor method. The liquid levels obtained by the capacitance probe for the two methods were compared with the liquid level estimated from the fluid temperature profiles. Results show that the dielectric constant corrected liquid levels agreed within 0.5 percent of the temperature profile estimated liquid level. The uncorrected dielectric constant capacitance liquid level measurements deviated from the temperature profile level by more than 5 percent. This paper identifies the magnitude of liquid level measurement error that can occur for LN2 and LH2 fluids due to temperature and pressure effects on the dielectric constants over the tank storage conditions from 5 to 40 psia. A method of reducing the level measurement errors by using dielectric constant correction factors based on fluid temperature and pressure measurements is derived. The improved accuracy by use of the correction factors is experimentally verified by comparing liquid levels derived from fluid temperature profiles.

Edwards, Lawrence G.; Haberbusch, Mark

1993-01-01

395

Determining factors for anodic polarization curves of typical structural materials of boiling water reactors in high temperature – high purity water  

Microsoft Academic Search

In order to examine the anodic polarization characteristics of typical structural materials of boiling water reactors (BWRs), the anodic polarization curves of type 316L stainless steel (316L SS) and Alloy 182 were measured in deaerated high purity water at 553 K using the previously reported measurement method which was confirmed suitable for high temperature – high purity water. In order to

Masahiko Tachibana; Kazushige Ishida; Yoichi Wada; Ryosuke Shimizu; Nobuyuki Ota; Nobuyoshi Hara

2012-01-01

396

PREDICTIVE THERMAL INACTIVATION MODEL FOR SALMONELLA SEROTYPES WITH TEMPERATURE, SODIUM LACTATE, NAC1 AND SODIUM PYROPHOSPHATE AS CONTROLLING FACTORS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Analyses of survival data of an eight strain cocktail of Salmonella spp. in ground beef with different concentrations of salt, sodium pyrophosphate (SPP), and sodium lactate (NaL) obtained after heating at different temperatures (55, 60, 65, and 71.1°C) indicated that heat resistance of Salmonella i...

397

Temperature during Incubation as One Factor Affecting the Distribution of Snake River Fall Chinook Salmon Spawning Areas  

Microsoft Academic Search

Spawning areas of ocean-type fall Chinook salmon Oncorhynchus tshawytscha in the Pacific Northwest are largely restricted to relatively warm coastal rivers. Fall Chinook salmon spawners in the Snake River basin clearly favor the main-stem Snake River and the relatively warm lower reaches of its tributaries. In this note, we describe how mean temperature during incubation affects fry emergence date and

William P. Connor; Charles E. Piston; Aaron P. Garcia

2003-01-01

398

Alternate stresses and temperature variation as factors of influence of ultrasonic vibration on mechanical and functional properties of shape memory alloys.  

PubMed

It is known that the main factors in a variation in the shape memory alloy properties under insonation are heating of the material and alternate stresses action. In the present work the experimental study of the mechanical behaviour and functional properties of shape memory alloy under the action of alternate stresses and varying temperature was carried out. The data obtained had demonstrated that an increase in temperature of the sample resulted in a decrease or increase in deformation stress depending on the structural state of the TiNi sample. It was shown that in the case of the alloy in the martensitic state, a decrease in stress was observed, and on the other hand, in the austenitic state an increase in stress took place. It was found that action of alternate stresses led to appearance of strain jumps on the strain-temperature curves during cooling and heating the sample through the temperature range of martensitic transformation under the constant stress. The value of the strain jumps depended on the amplitude of alternate stresses and the completeness of martensitic transformation. It was shown that the heat action of ultrasonic vibration to the mechanical behaviour of shape memory alloys was due to the non-monotonic dependence of yield stress on the temperature. The force action of ultrasonic vibration to the functional properties was caused by formation of additional oriented martensite. PMID:23870387

Belyaev, Sergey; Volkov, Alexander; Resnina, Natalia

2014-01-01

399

Nanowired drug delivery for neuroprotection in central nervous system injuries: modulation by environmental temperature, intoxication of nanoparticles, and comorbidity factors.  

PubMed

Recent developments in nanomedicine resulted in targeted drug delivery of active compounds into the central nervous system (CNS) either through encapsulated material or attached to nanowires. Nanodrug delivery by any means is supposed to enhance neuroprotection due to rapid accumulation of drugs within the target area and a slow metabolism of the compound. These two factors enhance neuroprotection than the conventions drug delivery. However, this is still uncertain whether nanodrug delivery could alter the pharmacokinetics of compounds making it more effective or just longer exposure of the compound for extended period of time is primarily responsible for enhanced effects of the drugs. Our laboratory is engaged in understanding of the nanodrug delivery using TiO(2) nanowires in CNS injuries models, for example, spinal cord injury (SCI), hyperthermia and/or intoxication of nanoparticles with or without other comorbidity factors, that is, diabetes or hypertension in rat models. Our observations suggest that nanowired drug delivery is effective under normal situation of SCI and hyperthermia as evidenced by significant reduction in the blood-brain barrier (BBB) breakdown, brain edema formation, cognitive disturbances, neuronal damages, and brain pathologies. However, when the pathophysiology of these CNS injuries is aggravated by nanoparticles intoxication or comorbidity factors, adjustment in dosage of nanodrug delivery is needed. This indicates that further research in nanomedicine is needed to explore suitable strategies in achieving greater neuroprotection in CNS injury in combination with nanoparticles intoxication or other comorbidity factors for better clinical practices. PMID:22162425

Sharma, Hari Shanker; Sharma, Aruna

2012-01-01

400

High Q-factor sapphire whispering gallery mode microwave resonator at single photon energies and millikelvin temperatures  

E-print Network

High Q-factor sapphire whispering gallery mode microwave resonator at single photon energies The microwave properties of a crystalline sapphire dielectric whispering gallery mode resonator have been with the implementation of a sapphire whispering gallery mode system. © 2011 American Institute of Physics. doi:10

Martinis, John M.

401

Magnesium correction to the NaKCa chemical geothermometer  

USGS Publications Warehouse

Equations and graphs have been devised to correct for the adverse effects of magnesium upon the Na-K-Ca chemical geothermometer. Either the equations or graphs can be used to determine appropriate temperature corrections for given waters with calculated NaKCa temperatures > 70??C and R 50 are probably derived from relatively cool aquifers with temperatures approximately equal to the measured spring temperature, irrespective of much higher calculated Na-K-Ca temperatures. ?? 1979.

Fournier, R.O.; Potter, R.W., II

1979-01-01