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1

Testing validity of the Tafel extrapolation method for monitoring corrosion of cold rolled steel in HCl solutions - Experimental and theoretical studies  

International Nuclear Information System (INIS)

The protection influence of glycine (Gly) and a one of its derivatives, namely 2-(bis(2-aminoethyl)amino) acetic acid, designated here as GlyD; where GlyD stands for 'glycine derivative', against cold rolled steel (CRS) corrosion was studied in aerated stagnant 1.0 M HCl solutions at 25 deg. C. Measurements were conducted under various experimental conditions using Tafel polarization, linear polarization and impedance techniques. These studies have shown that Gly and GlyD are very good 'green', mixed-type inhibitors. GlyD is more effective than Gly itself in inhibiting the acid corrosion of CRS. Electrochemical frequency modulation (EFM) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) method of analysis are also presented here for monitoring corrosion. Corrosion rates obtained from both EFM and ICP-AES methods are comparable with those recorded using Tafel extrapolation method, confirming validation of corrosion rates measured by the latter. Adsorption via H-bond is discussed here, based on the presence of oxide film on the electrode surface as well as the number of NH linkages in the inhibitor molecule. Quantum chemical method was also employed to explore the relationship between the inhibitor molecular properties and its protection efficiency. The density function theory (DFT) is used to study the structural properties of Gly and GlyD in aqueous phase in an attempt to understand their inhibition mechanism. The protection efficiencies of these csm. The protection efficiencies of these compounds showed a certain relationship to highest occupied molecular orbital (HOMO) energy, Mulliken atomic charges and Fukui indices.

2

Electrochemical frequency modulation and inductively coupled plasma atomic emission spectroscopy methods for monitoring corrosion rates and inhibition of low alloy steel corrosion in HCl solutions and a test for validity of the Tafel extrapolation method  

International Nuclear Information System (INIS)

The inhibition effect of glycine (Gly) towards the corrosion of low alloy steel ASTM A213 grade T22 boiler steel was studied in aerated stagnant 0.50 M HCl solutions in the temperature range 20-60 deg. C using potentiodynamic polarization (Tafel polarization and linear polarization) and impedance techniques, complemented with scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Electrochemical frequency modulation (EFM), a non-destructive corrosion measurement technique that can directly give values of corrosion current without prior knowledge of Tafel constants, is also presented here. Experimental corrosion rates determined by the Tafel extrapolation method are compared with corrosion rates obtained by electrochemical, namely EFM technique, and chemical (i.e., non-electrochemical) method for steel in HCl. The chemical method of confirmation of the corrosion rates involved determination of the dissolved cation, using ICP-AES (inductively coupled plasma atomic emission spectrometry) method of analysis. Corrosion rates (in mm y-1) obtained from the electrochemical (Tafel extrapolation and EFM) and the chemical method, ICP, are in a good agreement. Polarization studies have shown that Gly is a good 'green', mixed-type inhibitor with cathodic predominance. The inhibition process was attributed to the formation of an adsorbed film on the metal surface that protects the metal against corrosive agents. Scanning electron microscopy (SEM) and energanning electron microscopy (SEM) and energy dispersion X-ray (EDX) examinations of the electrode surface confirmed the existence of such an adsorbed film. The inhibition efficiency increases with increase in Gly concentration, while it decreases with solution temperature. Temkin isotherm is successfully applied to describe the adsorption process. Thermodynamic functions for the adsorption process were determined.

3

? ? scattering by pole extrapolation methods  

International Nuclear Information System (INIS)

A 25-inch hydrogen bubble chamber was used at the Lawrence Berkeley Laboratory Bevatron to produce 300,000 pictures of ?+p interactions at an incident momentum of the ?+ of 2.67 GeV/c. The 2-prong events were processed using the FSD and the FOG-CLOUDY-FAIR data reduction system. Events of the nature ?+p??+p?0 and ?+p??+?+n with values of momentum transfer to the proton of -t less than or equal to 0.238 GeV2 were selected. These events were used to extrapolate to the pion pole (t = m/sub ?/2) in order to investigate the ? ? interaction with isospins of both T=1 and T=2. Two methods were used to do the extrapolation: the original Chew-Low method developed in 1959 and the Durr-Pilkuhn method developed in 1965, which takes into account centrifugal barrier penetration factors. At first it seemed that, while the Durr-Pilkuhn method gave better values for the total ? ? cross section, the Chew-Low method gave better values for the angular distribution. Further analysis, however, showed that, if the requirement of total OPE (one-pion-exchange) was dropped, then the Durr-Pilkuhn method gave more reasonable values of the angular distribution as well as for the total ? ? cross section

4

? ? scattering by pole extrapolation methods  

International Nuclear Information System (INIS)

A 25-inch hydrogen bubble chamber was used at the Lawrence Berkeley Laboratory Bevatron to produce 300,000 pictures of ?+p interactions at an incident momentum of the ?+ of 2.67 GeV/c. The 2-prong events were processed using the FSD and the FOG-CLOUDY-FAIR data reduction system. Events of the nature ?+p ? ?+p?0 and ?+p ? ?+?+n with values of momentum transfer to the proton of -t less than or equal to 0.238 GeV2 were selected. These events were used to extrapolate to the pion pole (t = m/sub ?/2) in order to investigate the ? ? interaction with isospins of both T = 1 and T = 2. Two methods were used to do the extrapolation: the original Chew-Low method developed in 1959 and the Durr-Pilkuhn method developed in 1965 which takes into account centrifugal barrier penetration factors. At first it seemed that, while the Durr-Pilkuhn method gave better values for the total ? ? cross section, the Chew-Low method gave better values for the angular distribution. Further analysis, however, showed that if the requirement of total OPE (one-pion-exchange) were dropped, then the Durr-Pilkuhn method gave more reasonable values of the angular distribution as well as for the total ? ? cross section

5

Evaluation of corrosion rate from polarisation curves not exhibiting a Tafel region  

International Nuclear Information System (INIS)

Evaluation of corrosion rate by Tafel extrapolation is often impossible, simply because an experimental polarisation curve does not exhibit linear Tafel regions. This paper shows how such curves for the Fe/H2O/H+/O2 corrosion system can be accurately deconstructed to furnish both kinetic and thermodynamic parameters for the anodic and cathodic reactions. The curved anodic branch (due to film formation) is then amenable to correction for IR voltage drop and the resulting Tafel slope and other parameters are then substituted in the Tafel equation to accurately determine i corr. An alternative method to obtain the anodic Tafel slope has been used to validate the above approach. Polarisation curves describing the inhibition of mild steel in industrial cooling water were scanned/digitised from the literature

6

Extrapolation discontinuous Galerkin method for ultraparabolic equations  

Science.gov (United States)

Ultraparabolic equations arise from the characterization of the performance index of stochastic optimal control relative to ultradiffusion processes; they evidence multiple temporal variables and may be regarded as parabolic along characteristic directions. We consider theoretical and approximation aspects of a temporally order and step size adaptive extrapolation discontinuous Galerkin method coupled with a spatial Lagrange second-order finite element approximation for a prototype ultraparabolic problem. As an application, we value a so-called Asian option from mathematical finance.

Marcozzi, Michael D.

2009-02-01

7

Implicit extrapolation methods for multilevel finite element computations  

Energy Technology Data Exchange (ETDEWEB)

The finite element package FEMGP has been developed to solve elliptic and parabolic problems arising in the computation of magnetic and thermomechanical fields. FEMGP implements various methods for the construction of hierarchical finite element meshes, a variety of efficient multilevel solvers, including multigrid and preconditioned conjugate gradient iterations, as well as pre- and post-processing software. Within FEMGP, multigrid {tau}-extrapolation can be employed to improve the finite element solution iteratively to higher order. This algorithm is based on an implicit extrapolation, so that the algorithm differs from a regular multigrid algorithm only by a slightly modified computation of the residuals on the finest mesh. Another advantage of this technique is, that in contrast to explicit extrapolation methods, it does not rely on the existence of global error expansions, and therefore neither requires uniform meshes nor global regularity assumptions. In the paper the authors will analyse the {tau}-extrapolation algorithm and present experimental results in the context of the FEMGP package. Furthermore, the {tau}-extrapolation results will be compared to higher order finite element solutions.

Jung, M.; Ruede, U. [Technische Universitaet Chemnitz-Zwickau (Germany)

1994-12-31

8

A new extrapolation method for weak approximation schemes with applications  

CERN Document Server

We review Fujiwara's scheme, a sixth order weak approximation scheme for the numerical approximation of SDEs, and embed it into a general method to construct weak approximation schemes of order $ 2m $ for $ m \\in \\mathbf{N} $. Those schemes cannot be seen as cubature schemes, but rather as universal ways how to extrapolate from a lower order weak approximation scheme, namely the Ninomiya-Victoir scheme, for higher orders.

Oshima, Kojiro; Veluscek, Dejan

2009-01-01

9

Assessment of Load Extrapolation Methods for Wind Turbines  

DEFF Research Database (Denmark)

In the present paper, methods for statistical load extrapolation of wind-turbine response are studied using a stationary Gaussian process model, which has approximately the same spectral properties as the response for the out-of-plane bending moment of a windturbine blade. For a Gaussian process, an approximate analytical solution for the distribution of the peaks is given by Rice. In the present paper, three different methods for statistical load extrapolation are compared with the analytical solution for one mean wind speed. The methods considered are global maxima, block maxima, and the peak over threshold method with two different threshold values. The comparisons show that the goodness of fit for the local distribution has a significant influence on the results, but the peak over threshold method with a threshold value on the mean plus 1.4 standard deviations generally gives the best results. By considering Gaussian processes for 12 mean wind speeds, the “fitting before aggregation” and “aggregation before fitting” approaches are studied. The results show that the fitting before aggregation approach gives the best results.

Toft, Henrik Stensgaard; SØrensen, John Dalsgaard

2011-01-01

10

An Extrapolation Method for Estimating Truncation Errors in PSAs  

Energy Technology Data Exchange (ETDEWEB)

The quantification of a Probabilistic Safety Assessment (PSA) of a Nuclear Power Plant (NPP) is a complicated process and always has the Truncation Errors (TEs) in deleting low-probability cut sets. In practice it is extremely difficult to quantify PSA results without TEs. This paper proposes an approach to estimate the TEs in NPP PSAs which is based on the least square fitting and the extrapolation of risk increments. The proposed TE measure is reasonable and conservative. The proposed method can be helpful in demonstrating that the convergence of risk measures is sufficient

Choi, Jong Soo [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2010-10-15

11

Comparison of methods for extrapolating breaking creep results  

International Nuclear Information System (INIS)

Among all the methods of extrapolation, the following have been selected: - parametric methods (Larson-Miller, Dorn, Manson-Haferd); - digital and parametric method (minimum commitment); - digital method (finite differences); - descriptive method (Givar). The Larson-Miller, Dorn and Manson-Haferd methods are commonly used for analyzing the breaking creep results of materials for which the master curves can be described simply. The other methods have been developed in order to analyze the breaking creep results of materials where the structural changes over time modify the creep behaviour. In each case the assessment of the parameters is achieved by the least squares method. These methods were compared with each other on two steels, namely: Z6 CND 17-12 (316) and Z4 CND 35-20 (800 alloy). The various analyses performed show that (a) the predictions made as from the different methods are in good agreement between each other when there is a sufficient number of experimental values and (b) the predictions of the breaking times in the case of the 800 alloy differ from one method to the next. This result is due to the limited sampling data and to the complex behaviour of this alloy, the properties of which change with ageing

12

Extrapolated Boundary Element Method for Three-Dimensional Inductance Calculation  

Science.gov (United States)

In the case of a nearly perfect conductor, i.e., when the skin depth ? (in ordinary conductors) or the London penetration depth ?L (in superconductors) is much smaller than the other physical scales, the current flows only on the surface. Hence, the three-dimensional distribution of the magnetic field is fully specified by the two-dimensional current distribution (boundary elements) on the surface. The specific BEM (boundary element method) is called SCM (surface current method). In SCM, the surface is partitioned into N small areas, each with a looping current Ii (1 ? i ? N). I i's are determined by solving N simultaneous linear equations so as to eliminate the normal component of the magnetic field at the center of each area. The inductance is given in terms of the magnetic energy among N current loops. Thus, the problem is reduced to a two-dimensional one in SCM. To obtain the final results, the error estimate as a function of N is made and they are obtained as the extrapolation for N tending to infinity. Calculations for some examples including a fully three-dimensional object are presented. The effect of non-zero ? and ?L can be, in the present SCM, made by thinning the object by the amount ? (if the width of the conductor is larger than ?) but the more rigorous treatment is left for future study.

Hosoya, M.; Goto, E.; Soma, T.

1988-01-01

13

Multiplicative measurement error and the simulation extrapolation method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Whereas the literature on additive measurement error has known a considerable treatment, less work has been done for multiplicative noise. In this paper we concentrate on multiplicative measurement error in the covariates, which contrary to additive error not only modifies proportionally the original value, but also conserves the structural zeros. This paper compares three variants to specify the multiplicative measurement error model in the simulation step of the Simulation-Extrapolation (SI...

Biewen, Elena; Nolte, Sandra; Rosemann, Martin

2008-01-01

14

Extrapolation method for determining nuclear vertex constants by means of Pade approximation  

International Nuclear Information System (INIS)

Basing on the Pade approximation we develop a method to extrapolate the differential cross sections of the one-particle transfer reactions which is the nearest to the physical region. The extrapolation uncertainty is properly estimated. The method is applied to concrete reactions

15

Creep rupture strength extrapolation methods of four countries for AISI 316 stainless steel  

International Nuclear Information System (INIS)

Within the Structural Materials Activity Group of the Working Group for Codes and Standards for Fast Reactors of the European Communities, the member states have developed a study of extrapolation methods for creep data. The purpose of this work is to answer the question whether differences in national standards are caused by the extrapolation techniques in use or by actual differences in steels. It has been found that some differences do exist in the materials themselves, while the extrapolation techniques differ widely in the amount of data and the duration of tests. One of these methods has shown good flexibility and appears to be largely independent of amount of data. Accordingly the study concludes by recommending it for future application. (author)

16

A least square extrapolation method for improving solution accuracy of PDE computations  

CERN Document Server

Richardson extrapolation (RE) is based on a very simple and elegant mathematical idea that has been successful in several areas of numerical analysis such as quadrature or time integration of ODEs. In theory, RE can be used also on PDE approximations when the convergence order of a discrete solution is clearly known. But in practice, the order of a numerical method often depends on space location and is not accurately satisfied on different levels of grids used in the extrapolation formula. We propose in this paper a more robust and numerically efficient method based on the idea of finding automatically the order of a method as the solution of a least square minimization problem on the residual. We introduce a two-level and three-level least square extrapolation method that works on nonmatching embedded grid solutions via spline interpolation. Our least square extrapolation method is a post-processing of data produced by existing PDE codes, that is easy to implement and can be a better tool than RE for code v...

Garbey, M

2003-01-01

17

Study on Two Methods for Nonlinear Force-Free Extrapolation Based on Semi-Analytical Field  

Science.gov (United States)

In this paper, two semi-analytical solutions of force-free fields (Low and Lou, Astrophys. J. 352, 343, 1990) have been used to test two nonlinear force-free extrapolation methods. One is the boundary integral equation (BIE) method developed by Yan and Sakurai ( Solar Phys. 195, 89, 2000), and the other is the approximate vertical integration (AVI) method developed by Song et al. ( Astrophys. J. 649, 1084, 2006). Some improvements have been made to the AVI method to avoid the singular points in the process of calculation. It is found that the correlation coefficients between the first semi-analytical field and extrapolated field using the BIE method, and also that obtained by the improved AVI method, are greater than 90% below a height 10 of the 64×64 lower boundary. For the second semi-analytical field, these correlation coefficients are greater than 80% below the same relative height. Although differences between the semi-analytical solutions and the extrapolated fields exist for both the BIE and AVI methods, these two methods can give reliable results for heights of about 15% of the extent of the lower boundary.

Liu, S.; Zhang, H. Q.; Su, J. T.; Song, M. T.

2011-03-01

18

Parametric methods of describing and extrapolating the characteristics of long-term strength of refractory materials  

International Nuclear Information System (INIS)

This paper carries out the comparative analysis of the suitability of parametric methods for describing and extrapolating the results of longterm tests on refractory materials. Diagrams are presented of the longterm strength of niobium based alloys tested in a vacuum of 1.3 X 10-3 Pa. The predicted values and variance of the estimate of endurance of refractory alloys are presented by parametric dependences. The longterm strength characteristics can be described most adequately by the Manson-Sakkop and Sherby-Dorn methods. Several methods must be used to ensure the reliable extrapolation of the longterm strength characteristics to the time period an order of magnitude longer than the experimental data. The most suitable method cannot always be selected on the basis of the correlation ratio

19

Precise Numerical Results of IR-vertex and box integration with Extrapolation Method  

CERN Document Server

We present a new approach for obtaining very precise integration results for infrared vertex and box diagrams, where the integration is carried out directly without performing any analytic integration of Feynman parameters. Using an appropriate numerical integration routine with an extrapolation method, together with a multi-precision library, we have obtained integration results which agree with the analytic results to 10 digits even for such a very small photon mass as $10^{-150}$ GeV in the infrared vertex diagram.

Yuasa, F; Fujimoro, J; Hamaguchi, N; Ishikawa, T; Shimizu, Y

2007-01-01

20

Temperature-extrapolation method for Implicit Monte Carlo - Radiation hydrodynamics calculations  

International Nuclear Information System (INIS)

We present a method for implementing temperature extrapolation in Implicit Monte Carlo solutions to radiation hydrodynamics problems. The method is based on a BDF-2 type integration to estimate a change in material temperature over a time step. We present results for radiation only problems in an infinite medium and for a 2-D Cartesian hohlraum problem. Additionally, radiation hydrodynamics simulations are presented for an RZ hohlraum problem and a related 3D problem. Our results indicate that improvements in noise and general behavior are possible. We present considerations for future investigations and implementations. (authors)

 
 
 
 
21

Correction method for critical extrapolation of control-rods-rising during physical start-up of reactor  

International Nuclear Information System (INIS)

During physical start-up of nuclear reactor, the curve got by lifting the con- trol rods to extrapolate to the critical state is often in protruding shape, by which the supercritical phenomena is led. In the paper, the reason why the curve was in protruding was analyzed. A correction method was introduced, and the calculations were carried out by the practical data used in a nuclear power plant. The results show that the correction method reverses the protruding shape of the extrapolating curve, and the risk of reactor supercritical phenomena can be reduced using the extrapolated curve got by the correction method during physical start-up of the reactor. (authors)

22

Low-cost extrapolation method for maximal LTE radio base station exposure estimation: test and validation.  

Science.gov (United States)

An experimental validation of a low-cost method for extrapolation and estimation of the maximal electromagnetic-field exposure from long-term evolution (LTE) radio base station installations are presented. No knowledge on downlink band occupation or service characteristics is required for the low-cost method. The method is applicable in situ. It only requires a basic spectrum analyser with appropriate field probes without the need of expensive dedicated LTE decoders. The method is validated both in laboratory and in situ, for a single-input single-output antenna LTE system and a 2×2 multiple-input multiple-output system, with low deviations in comparison with signals measured using dedicated LTE decoders. PMID:23179190

Verloock, Leen; Joseph, Wout; Gati, Azeddine; Varsier, Nadège; Flach, Björn; Wiart, Joe; Martens, Luc

2013-06-01

23

Low-cost extrapolation method for maximal lte radio base station exposure estimation: Test and validation  

International Nuclear Information System (INIS)

An experimental validation of a low-cost method for extrapolation and estimation of the maximal electromagnetic-field exposure from long-term evolution (LTE) radio base station installations are presented. No knowledge on down-link band occupation or service characteristics is required for the low-cost method. The method is applicable in situ. It only requires a basic spectrum analyser with appropriate field probes without the need of expensive dedicated LTE decoders. The method is validated both in laboratory and in situ, for a single-input single-output antenna LTE system and a 2x2 multiple-input multiple-output system, with low deviations in comparison with signals measured using dedicated LTE decoders. (authors)

24

An extrapolation method for compressive strength prediction of hydraulic cement products  

Energy Technology Data Exchange (ETDEWEB)

The basis for the AMEBA Method is presented. A strength-time function is used to extrapolate the predicted cementitious material strength for a late (ALTA) age, based on two earlier age strengths--medium (MEDIA) and low (BAIXA) ages. The experimental basis for the method is data from the IPT-Brazil laboratory and the field, including a long-term study on concrete, research on limestone, slag, and fly-ash additions, and quality control data from a cement factory, a shotcrete tunnel lining, and a grout for structural repair. The method applicability was also verified for high-performance concrete with silica fume. The formula for predicting late age (e.g., 28 days) strength, for a given set of involved ages (e.g., 28,7, and 2 days) is normally a function only of the two earlier ages` (e.g., 7 and 2 days) strengths. This equation has been shown to be independent on materials variations, including cement brand, and is easy to use also graphically. Using the AMEBA method, and only needing to know the type of cement used, it has been possible to predict strengths satisfactorily, even without the preliminary tests which are required in other methods.

Siqueira Tango, C.E. de [IPT-Technological Research Inst., Sao Paulo (Brazil)

1998-07-01

25

Statistical Romberg extrapolation: A new variance reduction method and applications to option pricing  

CERN Document Server

We study the approximation of $\\mathbb{E}f(X_T)$ by a Monte Carlo algorithm, where $X$ is the solution of a stochastic differential equation and $f$ is a given function. We introduce a new variance reduction method, which can be viewed as a statistical analogue of Romberg extrapolation method. Namely, we use two Euler schemes with steps $\\delta$ and $\\delta^{\\beta},0<\\beta<1$. This leads to an algorithm which, for a given level of the statistical error, has a complexity significantly lower than the complexity of the standard Monte Carlo method. We analyze the asymptotic error of this algorithm in the context of general (possibly degenerate) diffusions. In order to find the optimal $\\beta$ (which turns out to be $\\beta=1/2$), we establish a central limit type theorem, based on a result of Jacod and Protter for the asymptotic distribution of the error in the Euler scheme. We test our method on various examples. In particular, we adapt it to Asian options. In this setting, we have a CLT and, as a by-produc...

Kebaier, A

2005-01-01

26

Activity determination of (41)Ar using efficiency extrapolation method and 4??(PS)-4??(NaI) coincidence system.  

Science.gov (United States)

Noble gas (41)Ar was measured with a 4??-4?? coincidence system, in which gamma- and beta-rays were respectively detected with a well-type NaI(Tl) and plastic scintillator (PS) detector. The activity of (41)Ar was determined from an efficiency extrapolation method, in which the beta detector efficiency was varied by electronic discrimination using the software developed under Visual basic. In addition, high resolution gamma spectroscopy with HPGe detector was also used for activity determination of (41)Ar, and the result was satisfactory in agreement with that obtain by the efficiency extrapolation method. This work demonstrated that the activity of (41)Ar can be accurately measured by efficiency extrapolation method. PMID:25527895

Xie, Feng; Li, Xuesong; Dai, Yihua; Jiang, Wengang; He, Xiaobing; Yu, Gongshuo; Ni, Jianzhong

2015-03-01

27

A New Implementation of the Magnetohydrodynamics-Relaxation Method for Nonlinear Force-Free Field Extrapolation in the Solar Corona  

CERN Document Server

Magnetic field in the solar corona is usually extrapolated from photospheric vector magnetogram using a nonlinear force-free field (NLFFF) model. NLFFF extrapolation needs a considerable effort to be devoted for its numerical realization. In this paper we present a new implementation of the magnetohydrodynamics (MHD)-relaxation method for NLFFF extrapolation. The magneto-frictional approach which is introduced for speeding the relaxation of the MHD system is novelly realized by the spacetime conservation-element and solution-element (CESE) scheme. A magnetic field splitting method is used to further improve the computational accuracy. The bottom boundary condition is prescribed by changing the transverse field incrementally to match the magnetogram, and all other artificial boundaries of the computational box are simply fixed. We examine the code by two types of NLFFF benchmark tests, the Low & Lou (1990) semi-analytic force-free solutions and a more realistic solar-like case constructed by van Ballegooij...

Jiang, Chaowei

2012-01-01

28

Defect image with transversal and longitudinal super-resolution achieved with two-measure adaptive extrapolation method  

International Nuclear Information System (INIS)

Results of applying the method of two-measure adaptive extrapolation (modification of Hershberg-Papoulis algorithm) to achieve superresolution of defect images, reconstructed according to multifrequency acoustic digital holograms are considered. Increase of transversal and longitudinal resolutions by the factor of 4 and 2 respectively is obtained in experiments on processing images of point and volume defects. 17 refs., 4 figs., 1 tab

29

An investigation of the relationship between extrapolation parameters and approximate solutions in solving fuzzy linear systems using refinement of jacobi over relaxation method  

International Nuclear Information System (INIS)

Extrapolation parameters in Refinement of Jacobi over Relation method in solving fuzzy linear systems were hypothesized to influence the rate of convergence. This paper aims to investigate the relationship between extrapolation parameters and approximate solutions of fuzzy linear systems when solved using Refinement of Jacobi over Relaxation method. The Algorithms of Refinement of Jacobi over Relaxation method are proposed based on the Jacobi method that specifically used in solving the system. A five by five fuzzy linear system is given to investigate the convergence to exact solution with three different values of extrapolation parameters. The numerical results show that there is a positive correlation between extrapolation parameter and convergence to exact solution. The three extrapolation parameters suggest that convergence to exact solution can be increased in line with the increase in the values of extrapolation parameters.

30

Comparison of extrapolation methods for creep rupture stresses of 12Cr and 18Cr10NiTi steels  

International Nuclear Information System (INIS)

As a part of a Soviet-Swedish research programme the creep rupture properties of two heat resisting steels namely a 12% Cr steel and an 18% Cr12% Ni titanium stabilized steel have been studied. One heat from each country of both steels were creep tested. The strength of the 12% Cr steels was similar to earlier reported strength values, the Soviet steel being some-what stronger due to a higher tungsten content. The strength of the Swedish 18/12 Ti steel agreed with earlier results, while the properties of the Soviet steel were inferior to those reported from earlier Soviet creep testings. Three extrapolation methods were compared on creep rupture data collected in both countries. Isothermal extrapolation and an algebraic method of Soviet origin gave in many cases rather similar results, while the parameter method recommended by ISO resulted in higher rupture strength values at longer times. (author)

31

Linear extrapolation distance for a black cylindrical control rod with the pulsed neutron method  

International Nuclear Information System (INIS)

The objective of this experiment was to measure the linear extrapolation distance for a central black cylindrical control rod in a cylindrical water moderator. The radius for both the control rod and the moderator was varied. The pulsed neutron technique was used and the decay constant was measured for both a homogeneous and a heterogeneous system. From the difference in the decay constants the extrapolation distance could be calculated. The conclusion is that within experimental error it is safe to use the approximate formula given by Pellaud or the more exact one given by Kavenoky. We can also conclude that linear anisotropic scattering is accounted for in a correct way in the approximate formula given by Pellaud and Prinja and Williams

32

A comparison of high-order explicit Runge–Kutta, extrapolation, and deferred correction methods in serial and parallel  

We compare the three main types of high-order one-step initial value solvers: extrapolation, spectral deferred correction, and embedded Runge–Kutta pairs. We consider orders four through twelve, including both serial and parallel implementations. We cast extrapolation and deferred correction methods as fixed-order Runge–Kutta methods, providing a natural framework for the comparison. The stability and accuracy properties of the methods are analyzed by theoretical measures, and these are compared with the results of numerical tests. In serial, the eighth-order pair of Prince and Dormand (DOP8) is most efficient. But other high-order methods can be more efficient than DOP8 when implemented in parallel. This is demonstrated by comparing a parallelized version of the wellknown ODEX code with the (serial) DOP853 code. For an N-body problem with N = 400, the experimental extrapolation code is as fast as the tuned Runge–Kutta pair at loose tolerances, and is up to two times as fast at tight tolerances.

Ketcheson, David I.

2014-06-13

33

Standardization of I-125 solution by extrapolation of an efficiency wave obtained by coincidence X-(X-?) counting method  

International Nuclear Information System (INIS)

The activity concentration of 125I was determined by X-(X-?) coincidence counting method and efficiency extrapolation curve. The measurement system consists of 2 thin NaI(T1) scintillation detectors which are horizontally movable on a track. The efficiency curve is obtained by symmetricaly changing the distance between the source and the detectors and the activity is determined by applying a linear efficiency extrapolation curve. All sum-coincidence events are included between 10 and 100 KeV window counting and the main source of uncertainty is coming from poor counting statistic around zero efficiency. The consistence of results with other methods shows that this technique can be applied to photon cascade emitters and are not discriminating by the detectors. It has been also determined the 35,5 KeV gamma-ray emission probability of 125I by using a Gamma-X type high purity germanium detector. (author)

34

Comparison among creep rupture strength extrapolation methods with application to data for AISI 316 SS from Italy, France, U.K. and F.R.G  

International Nuclear Information System (INIS)

Inside Activity 3 ''Materials'' of WGCS, the member states UK and FRG have developed a work regarding extrapolation methods for creep data. This work has been done by comparising extrapolation methods in use in their countries by applying them to creep rupture strength data on AISI 316 SS obtained in UK and FRG. This work has been issued on April 1978 and the Community has dealed it to all Activity 3 Members. Italy, in the figure of NIRA S.p.A., has received, from the European Community a contract to extend the work to Italian and French data, using extrapolation methods currently in use in Italy. The work should deal with the following points: - Collect of Italian experimental data; - Chemical analysis on Italian Specimen; - Comparison among Italian experimental data with French, FRG and UK data; - Description of extrapolation methods in use in Italy; - Application of these extrapolation methods to Italian, French, British and Germany data; - Extensions of a Final Report

35

Preprocess the Photospheric Vector Magnetograms for NLFFF Extrapolation using a Potential Field Model and an Optimization Method  

CERN Document Server

Numerical reconstruction/extrapolation of coronal nonlinear force-free magnetic field (NLFFF) usually takes the photospheric vector magnetogram as input at the bottom boundary. Magnetic field observed at the photosphere, however, contains force which is in conflict with the fundamental assumption of the force-free model and measurement noise which is unfavorable for practical computation. Preprocessing of the raw magnetogram has been proposed by Wiegelmann, Inhester, and Sakurai (2006) to remove the force and noise for providing better input for NLFFF modeling. In this paper we develop a new code of magnetogram preprocessing which is consistent with our extrapolation method CESE-MHD-NLFFF (Jiang, Feng, and Xiang, 2012; Jiang and Feng, 2012). Basing on a magnetic-splitting rule that a magnetic field can be split into a potential field part and a non-potential part, we split the magnetogram and deal with the two parts separately. Preprocessing of the magnetogram's potential part is based on a numerical potentia...

Jiang, Chaowei

2013-01-01

36

Evaluation of external quality factor of the superconducting cavity using extrapolation method  

International Nuclear Information System (INIS)

The estimation of the external quality factor is important for designing coupling devices for the cavities. A new representation of the external quality factor calculations for single-cell cavity coupled to a coaxial transmission line is derived based on analytic analysis and numeric analysis with the help of 3D electromagnetic code, and verified with experimental measurements at room temperature. In logarithmic scale the results for the external quality factor were quasi-linear over the limited range, and the simulated and measured data could be used and extrapolated to the superconducting case. For the unpolished 1.5 GHz 3rd harmonic superconducting cavity, the discrepancy between the evaluation value and measurement result is less than 25% within an acceptable deviation. (authors)

37

Improvement of flux distribution calculation using the extrapolation method of Richardson  

International Nuclear Information System (INIS)

Richardson have advanced a method for increasing the accuracy in numerical solving of linear differential equations. So, he proposed several schemes for performing algorythms, in which various approximtion parameters are used. It has been proved that a linear combination of this solution under certain circumstances gives a higher accuracy. Starting from these facts the present paper descpibes the application of the Richardson's method in improving the neutron flux calculation by using the EXTERMINATOR-2-INPR code. The considered benchmark problem has been conceived by D.R.Vondy from ORNL-USA. It consists of solving the multigroup diffusion equations for homogeneous two-dimensional slab. The results obtained show the efficiency of the Richardson method in improving the neutron flux calculation and constitutes a basis for achieving algorythms for other categories of problems. (authors)

38

An approach to estimating and extrapolating model error based on inverse problem methods: towards accurate numerical weather prediction  

Science.gov (United States)

Model error is one of the key factors restricting the accuracy of numerical weather prediction (NWP). Considering the continuous evolution of the atmosphere, the observed data (ignoring the measurement error) can be viewed as a series of solutions of an accurate model governing the actual atmosphere. Model error is represented as an unknown term in the accurate model, thus NWP can be considered as an inverse problem to uncover the unknown error term. The inverse problem models can absorb long periods of observed data to generate model error correction procedures. They thus resolve the deficiency and faultiness of the NWP schemes employing only the initial-time data. In this study we construct two inverse problem models to estimate and extrapolate the time-varying and spatial-varying model errors in both the historical and forecast periods by using recent observations and analogue phenomena of the atmosphere. Numerical experiment on Burgers' equation has illustrated the substantial forecast improvement using inverse problem algorithms. The proposed inverse problem methods of suppressing NWP errors will be useful in future high accuracy applications of NWP.

Hu, Shu-Juan; Qiu, Chun-Yu; Zhang, Li-Yun; Huang, Qi-Can; Yu, Hai-Peng; Chou, Ji-Fan

2014-08-01

39

Thermal plumes in ventilated rooms : Measurements in stratified surroundings and analysis by use of an extrapolation method  

DEFF Research Database (Denmark)

The design of a displacement ventilation system involves determination of the flow rate in the thermal plumes. The flow rate in the plumes and the vertical temperature gradient influence each other, and they are influenced by many factors. This paper shows some descriptions of these effects. Free turbulent plumes from different heated bodies are investigated. The measurements have taken place in a full-scale test room where the vertical temperature gradient have been changed. The velocity and the temperature distribution in the plume are measured. Large scale plume axis wandering is taken into account and the temperature excess and the velocity distribution are calculated by use of an extrapolation method. In the case with a concentrated heat source (dia 50mm, 343W) and nearly uniform surroundings the model of a plume above a point heat source is verified. It represents a borderline case with the smallest entrainment factor and the smallest angle of spread. Due to the measuring method and data processing the velocity and temperature excess profiles are observed more narrowly than those reported by previous authors. In the case with an extensive heat source (dia 400mm, lOOW) the model of a plume above a point heat source cannot be used. This is caused either by the way of generating the plume including a long intermediate region or by the environmental conditions where vertical temperature gradients are present. The flow has a larger angle of spread and the entrainment factor is greather than for a point heat source. The exact knowledge of the vertical temperature gradient is essential to predict the flow propagation due to its influence on the entrainment, e.g. in an integral method of plume calculation • Since the flow from different heated bodies is individual full-scale measurements seem to be the only possible approach to obtain the volume flow in: thermal plumes in ventilated rooms.

Kofoed, Peter; Nielsen, Peter V.

1990-01-01

40

First principles Tafel kinetics of methanol oxidation on Pt(111)  

Science.gov (United States)

Electrocatalytic methanol oxidation is of fundamental importance in electrochemistry and also a key reaction in direct methanol fuel cell. To resolve the kinetics at the atomic level, this work investigates the potential-dependent reaction kinetics of methanol oxidation on Pt(111) using the first principles periodic continuum solvation model based on modified-Poisson-Boltzmann equation (CM-MPB), focusing on the initial dehydrogenation elementary steps. A theoretical model to predict Tafel kinetics (current vs potential) is established by considering that the rate-determining step of methanol oxidation (to CO) is the first Csbnd H bond breaking (CH3OH(aq) ? CH2OH* + H*) according to the computed free energy profile. The first Csbnd H bond breaking reaction needs to overcome a large entropy loss during methanol approaching to the surface and replacing the adsorbed water molecules. While no apparent charge transfer is involved in this elementary step, the charge transfer coefficient of the reaction is calculated to be 0.36, an unconventional value for charge transfer reactions, and the Tafel slope is deduced to be 166 mV. The results show that the metal/adsorbate interaction and the solvation environment play important roles on influencing the Tafel kinetics. The knowledge learned from the potential-dependent kinetics of methanol oxidation can be applied in general for understanding the electrocatalytic reactions of organic molecules at the solid-liquid interface.

Fang, Ya-Hui; Liu, Zhi-Pan

2015-01-01

 
 
 
 
41

Interpolation and extrapolation method to analyze irradiation-induced dimensional change data of graphite for design of core components in very high temperature reactor (VHTR)  

International Nuclear Information System (INIS)

Graphite materials are used as core components in the High-Temperature Gas-Cooled Reactor (HTGR) and Very High Temperature Reactor (VHTR). The authors prepared technical documents for design, material, products, in-service inspection and maintenance of the graphite components for the HTGR/VHTR, which were summarized as a draft of standard for the graphite components through discussion made in a 'Special committee on research on preparation for codes for graphite components in HTGR' set up within AESJ. The draft of standard contains graphical expressions for the irradiated material properties of IG-110 graphite. It is possible to use the graphical expressions for the components design of VHTR. The graphs were obtained based on the interpolation and extrapolation of the irradiation data. The irradiation-induced dimensional change of IG-110 graphite was obtained through the interpolation and extrapolation of the irradiation data with a quadratic equation of fast neutron fluence. The irradiation data for H-451 and ATR-2E graphites were used for the evaluation of the interpolation and extrapolation of irradiation data for IG-110. It was shown in this study that the proposed interpolation and extrapolation method is reasonable for IG-110 with regard to the database available at present. (author)

42

Extrapolation and perturbation schemes for accelerating the convergence of quantum mechanical free energy calculations via the Fourier path-integral Monte Carlo method  

International Nuclear Information System (INIS)

We present two simple but effective techniques designed to improve the rate of convergence of the Fourier path-integral Monte Carlo method for quantum partition functions with respect to the Fourier space expansion length, K, especially at low temperatures. The first method treats the high Fourier components as a perturbation, and the second method involves an extrapolation of the partition function (or perturbative correction to the partition function) with respect to the parameter K. We perform a sequence of calculations at several values of K such that the statistical errors for the set of results are correlated, and this permits extremely accurate extrapolations. We demonstrate the high accuracy and efficiency of these new approaches by computing partition functions for H2O from 296 to 4000 K and comparing to the accurate results of Partridge and Schwenke. (c) 2000 American Institute of Physics

43

A review of creep-fatigue life prediction methods: Identification and extrapolation to long term and low strain cyclic loading  

International Nuclear Information System (INIS)

Eight creep-fatigue interaction models are identified on a set of LCF experimental data. The material is 316 L type stainless steel, the temperature is 6000C. The general agreement between tests and predictions is good in the experimental range. Tentative extrapolations are made towards low strain and along dwell. Opposite trends are then pointed out on stress dependent and strain range dependent models. The final results are still encouraging and general rules are given concerning the long term life prediction. (orig.)

44

Accurate ab initio potential energy curve of F2. I. Nonrelativistic full valence configuration interaction energies using the correlation energy extrapolation by intrinsic scaling method  

Science.gov (United States)

The recently introduced method of correlation energy extrapolation by intrinsic scaling (CEEIS) is used to calculate the nonrelativistic electron correlations in the valence shell of the F2 molecule at 13 internuclear distances along the ground state potential energy curve from 1.14Åto8Å, the equilibrium distance being 1.412Å. Using Dunning's correlation-consistent double-, triple-, and quadruple-zeta basis sets, the full configuration interaction energies are determined, with an accuracy of about 0.3mhartree, by successively generating up to octuple excitations with respect to multiconfigurational reference functions that strongly change along the reaction path. The energies of the reference functions and those of the correlation energies with respect to these reference functions are then extrapolated to their complete basis set limits. The applicability of the CEEIS method to strongly multiconfigurational reference functions is documented in detail.

Bytautas, Laimutis; Nagata, Takeshi; Gordon, Mark S.; Ruedenberg, Klaus

2007-10-01

45

Infrared extrapolations for atomic nuclei  

CERN Document Server

Harmonic oscillator model-space truncations introduce systematic errors to the calculation of binding energies and other observables. We identify the relevant infrared scaling variable and give values for this nucleus-dependent quantity. We consider isotopes of oxygen computed with the coupled-cluster method from chiral nucleon-nucleon interactions at next-to-next-to-leading order and show that the infrared component of the error is sufficiently understood to permit controlled extrapolations. By employing oscillator spaces with relatively large frequencies, well above the energy minimum, the ultraviolet corrections can be suppressed while infrared extrapolations over tens of MeVs are accurate for ground-state energies. However, robust uncertainty quantification for extrapolated quantities that fully accounts for systematic errors is not yet developed.

Furnstahl, R J; Papenbrock, T; Wendt, K A

2014-01-01

46

Extrapolation of stable random fields  

CERN Document Server

In this paper, we discuss three extrapolation methods for alpha-stable random fields with 1method and providing sufficient conditions for path continuity. Two methods are based on minimizing the variability of the difference between the predictor and the theoretical value, whereas in the third approach we provide a new method that maximizes the covariation between these two quantities.

Karcher, Wolfgang; Spodarev, Evgeny

2011-01-01

47

ZEKE photoelectron spectroscopy of p-fluorophenol···H2S/H2O complexes and dissociation energy measurement using the Birge-Sponer extrapolation method.  

Science.gov (United States)

In this work we have shown that the Birge-Sponer extrapolation method can be successfully used to determine the dissociation energies (D0) of noncovalently bound complexes. The O-H···S hydrogen-bonding interaction in the cationic state of the p-fluorophenol···H2S complex was characterized using zero kinetic energy (ZEKE) photoelectron spectroscopy. This is the first ZEKE report on the O-H···S hydrogen-bonding interaction. The adiabatic ionization energy (AIE) of the complex was determined as 65?542 cm(-1). Various intermolecular and intramolecular vibrational modes of the cation were assigned. A long progression was observed in the intermolecular stretching mode (?) of the complex with significant anharmonicity along this mode. The anharmonicity information was used to estimate the dissociation energy (D0) in the cationic state using the Birge-Sponer extrapolation method. The D0 was estimated as 9.72 ± 1.05 kcal mol(-1). The ZEKE photoelectron spectra of analogous complex FLP···H2O was also recorded for the sake of comparison. The AIE was determined as 64?082 cm(-1). The intermolecular stretching mode in this system, however, was found to be quite harmonic, unlike that in the H2S complex. The dissociation energies of both the complexes, along with those of a few benchmark systems, such as phenol···H2O and indole···benzene complexes, were computed at various levels of theory such as MP2 at the complete basis set limit, ?B97X-D, and CCSD(T). It was found that only the ?B97X-D level values were in excellent agreement with the experimental results for the benchmark systems for the ground as well as the cationic states. The dissociation energy of the (FLP···H2S)(+) complex determined by the Birge-Sponer extrapolation was about ?18% lower than that computed at the ?B97X-D level. PMID:25250474

Bhattacharyya, Surjendu; Wategaonkar, Sanjay

2014-10-01

48

Finite lattice extrapolation algorithms  

International Nuclear Information System (INIS)

Two algorithms for sequence extrapolation, due to von den Broeck and Schwartz and Bulirsch and Stoer are reviewed and critically compared. Applications to three states and six states quantum chains and to the (2+1)D Ising model show that the algorithm of Bulirsch and Stoer is superior, in particular if only very few finite lattice data are available. (orig.)

49

Coherence extrapolation for underwater ambient noise.  

Science.gov (United States)

This paper considers extrapolation of the vertical coherence of surface-generated oceanic ambient noise to simulate measurements made on a longer sensor array. The extrapolation method consists of projecting the noise coherence measured with a limited aperture array into the domain spanned by prolate spheroidal wave functions, which are an orthogonal basis defined by array parameters and the noise frequency. Using simulated data corresponding to selected multi-layered seabeds as ground truth, the performance of the extrapolation method is explored. Application of the technique is also demonstrated on experimental data. PMID:24907840

Quijano, Jorge E; Dosso, Stan E; Siderius, Martin; Muzi, Lanfranco

2014-06-01

50

Ecotoxicological effects extrapolation models  

Energy Technology Data Exchange (ETDEWEB)

One of the central problems of ecological risk assessment is modeling the relationship between test endpoints (numerical summaries of the results of toxicity tests) and assessment endpoints (formal expressions of the properties of the environment that are to be protected). For example, one may wish to estimate the reduction in species richness of fishes in a stream reach exposed to an effluent and have only a fathead minnow 96 hr LC50 as an effects metric. The problem is to extrapolate from what is known (the fathead minnow LC50) to what matters to the decision maker, the loss of fish species. Models used for this purpose may be termed Effects Extrapolation Models (EEMs) or Activity-Activity Relationships (AARs), by analogy to Structure-Activity Relationships (SARs). These models have been previously reviewed in Ch. 7 and 9 of and by an OECD workshop. This paper updates those reviews and attempts to further clarify the issues involved in the development and use of EEMs. Although there is some overlap, this paper does not repeat those reviews and the reader is referred to the previous reviews for a more complete historical perspective, and for treatment of additional extrapolation issues.

Suter, G.W. II

1996-09-01

51

A fast marching approach to multidimensional extrapolation  

Science.gov (United States)

A computationally efficient approach to extrapolating a data field with second order accuracy is presented. This is achieved through the sequential solution of non-homogeneous linear static Hamilton-Jacobi equations, which can be performed rapidly using the fast marching methodology. In particular, the method relies on a fast marching calculation of the distance from the manifold ? that separates the subdomain ?in over which the quanity is known from the subdomain ?out over which the quantity is to be extrapolated. A parallel algorithm is included and discussed in the appendices. Results are compared to the multidimensional partial differential equation (PDE) extrapolation approach of Aslam (Aslam (2004) [31]). It is shown that the rate of convergence of the extrapolation within a narrow band near ? is controlled by both the number of successive extrapolations performed and the order of accuracy of the spatial discretization. For m successive extrapolating steps and a spatial discretization scheme of order N, the rate of convergence in a narrow band is shown to be min(N+1,m+1). Results show that for a wide range of error levels, the fast marching extrapolation strategy leads to dramatic improvements in computational cost when compared to the PDE approach.

McCaslin, Jeremy O.; Courtine, Émilien; Desjardins, Olivier

2014-10-01

52

Load Extrapolation During Operation for Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the recent years load extrapolation for wind turbines has been widely considered in the wind turbine industry. Loads on wind turbines during operations are normally dependent on the mean wind speed, the turbulence intensity and the type and settings of the control system. All these parameters must be taken into account when characteristic load effects during operation are determined. In the wind turbine standard IEC 61400-1 a method for load extrapolation using the peak over threshold meth...

Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

2008-01-01

53

Experimental check of the use of unconventional reference materials for EDS analysis in a TEM by extrapolation method based on pure elements  

International Nuclear Information System (INIS)

In this work, the use of unconventional reference materials to determine experimentally the Cliff-Lorimer factor for EDS quantitative analysis with a TEM is checked by means of an alternative experimental procedure. The k-factor is determined by the extrapolation method based on pure elements, by measuring the normalized X-ray intensities emitted by thin films of pure gold and pure silver of different thickness, accurately measured by X-ray reflectivity. The goal of this work is to confirm the value of the k-factor previously obtained by the use of unconventional reference materials consisting of a bi-layer of pure gold on pure silver. The current result is in accordance with the previous one when considering their error bars, however, their relative difference is about 13 %, probably due to some uncertainties in mass thickness measurements. The mass thickness measurement of the layers of pure elements needs to be performed by different methods in order to reduce its uncertainty.

54

Interspecies extrapolation of physiological pharmacokinetic parameter distributions.  

Science.gov (United States)

Three methods (multiplicative, additive, and allometric) were developed to extrapolate physiological model parameter distributions across species, specifically from rats to humans. In the multiplicative approach, the rat model parameters are multiplied by the ratio of the mean values between humans and rats. Additive scaling of the distributions is defined by adding the difference between the average human value and the average rat value to each rat value. Finally, allometric scaling relies on established extrapolation relationships using power functions of body weight. A physiologically-based pharmacokinetic model was fitted independently to rat and human benzene disposition data. Human model parameters obtained by extrapolation and by fitting were used to predict the total bone marrow exposure to benzene and the quantity of metabolites produced in bone marrow. We found that extrapolations poorly predict the human data relative to the human model. In addition, the prediction performance depends largely on the quantity of interest. The extrapolated models underpredict bone marrow exposure to benzene relative to the human model. Yet, predictions of the quantity of metabolite produced in bone marrow are closer to the human model predictions. These results indicate that the multiplicative and allometric techniques were able to extrapolate the model parameter distributions, but also that rats do not provide a good kinetic model of benzene disposition in humans. PMID:8972106

Watanabe, K H; Bois, F Y

1996-12-01

55

SPATIAL EXTRAPOLATION OF ANISOTROPIC ROAD TRAFFIC DATA  

Directory of Open Access Journals (Sweden)

Full Text Available A method of spatial extrapolation of traffic data is proposed. The traffic data is given by GPS signals over downtown Berlin sent by approximately 300 taxis. To reconstruct the traffic situation at a given time spatially, i.e., in the form of traffic maps, kriging with moving neighborhood based on residuals is used. Due to significant anisotropy in directed traffic data, the classical kriging has to be modified in order to include additional information. To verify the extrapolation results, test examples on the basis of a well-known model of stochastic geometry, the Boolean random function are considered.

Hans Braxmeier

2011-05-01

56

Uncertainties of Euclidean Time Extrapolation in Lattice Effective Field Theory  

CERN Document Server

Extrapolations in Euclidean time form a central part of Nuclear Lattice Effective Field Theory (NLEFT) calculations using the Projection Monte Carlo method, as the sign problem in many cases prevents simulations at large Euclidean time. We review the next-to-next-to-leading order NLEFT results for the alpha nuclei up to $^{28}$Si, with emphasis on the Euclidean time extrapolations, their expected accuracy and potential pitfalls. We also discuss possible avenues for improving the reliability of Euclidean time extrapolations in NLEFT.

Lähde, Timo A; Krebs, Hermann; Lee, Dean; Meißner, Ulf-G; Rupak, Gautam

2014-01-01

57

The extrapolated-efficiency method, a new technique to determine the ?-cascade detection efficiency in experiments based on the surrogate-reaction method  

Energy Technology Data Exchange (ETDEWEB)

The surrogate-reaction method is an indirect technique to extract neutron-induced cross-sections of short-lived nuclei. In the last years several experiments have been performed to investigate whether this technique can be applied to infer radiative-capture cross-sections. A major difficulty in this type of measurements is the determination of the gamma-cascade detection efficiency. The pulse-height weighting technique (PHWT) has been previously used to determine this quantity in surrogate experiments. In this work, we present a new method to determine the gamma-cascade detection efficiency in the vicinity of the neutron-separation energy that is much simpler than the PHWT. We also investigate the possibility to apply this new technique in standard experiments using neutron beams.

Boutoux, G., E-mail: guillaume.boutoux@cea.fr [CNRS, IN2P3, CENBG, UMR 5797, F-33175 Gradignan (France); University Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); CEA DAM DIF, F-91297 Arpajon (France); Jurado, B.; Mathieu, L. [CNRS, IN2P3, CENBG, UMR 5797, F-33175 Gradignan (France); University Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); Méot, V. [CEA DAM DIF, F-91297 Arpajon (France); Aïche, M.; Barreau, G. [CNRS, IN2P3, CENBG, UMR 5797, F-33175 Gradignan (France); University Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); Blanc, A. [CEA DAM DIF, F-91297 Arpajon (France); Companis, I. [CNRS, IN2P3, CENBG, UMR 5797, F-33175 Gradignan (France); University Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); Roig, O.; Théroine, C. [CEA DAM DIF, F-91297 Arpajon (France)

2013-02-01

58

Load Extrapolation During Operation for Wind Turbines  

DEFF Research Database (Denmark)

In the recent years load extrapolation for wind turbines has been widely considered in the wind turbine industry. Loads on wind turbines during operations are normally dependent on the mean wind speed, the turbulence intensity and the type and settings of the control system. All these parameters must be taken into account when characteristic load effects during operation are determined. In the wind turbine standard IEC 61400-1 a method for load extrapolation using the peak over threshold method is recommended. In this paper this method is considered and some of the assumptions are examined. The statistical uncertainty related to the limited number of simulations of the response during operation is explored together with the influence of the threshold value.

Toft, Henrik Stensgaard; SØrensen, John Dalsgaard

2008-01-01

59

Biosimilars: the science of extrapolation.  

Science.gov (United States)

Despite the establishment of a specific approval pathway, the issuance of detailed scientific guidelines for the development of similar biological medicinal products (so-called "biosimilars") and the approval of several biosimilars in the European Union, acceptance of biosimilars in the medical community continues to be low. This is especially true in therapeutic indications for which no specific clinical trials with the biosimilar have been performed and that have been licensed based on extrapolation of efficacy and safety data from other indications. This article addresses the concerns frequently raised in the medical community about the use of biosimilars in such extrapolated indications and explains the underlying scientific and regulatory decision making including some real-life examples from recently licensed biosimilars. PMID:25298038

Weise, Martina; Kurki, Pekka; Wolff-Holz, Elena; Bielsky, Marie-Christine; Schneider, Christian K

2014-11-20

60

Extrapolating future Arctic ozone losses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Future increases in the concentration of greenhouse gases and water vapour may cool the stratosphere further and increase the amount of polar stratospheric clouds (PSCs). Future Arctic PSC areas have been extrapolated from the highly significant trends 1958-2001. Using a tight correlation between PSC area and the total vortex ozone depletion and taking the decreasing amounts of ozone depleting substances into account we make empirical estimates of future ozone. The result is that Arctic ozone...

Knudsen, B. M.; Andersen, S. B.; Christiansen, B.; Larsen, N.; Rex, M.; Harris, N. R. P.; Naujokat, B.

2004-01-01

 
 
 
 
61

3D Hail Size Distribution Interpolation/Extrapolation Algorithm  

Science.gov (United States)

Radar data can usually detect hail; however, it is difficult for present day radar to accurately discriminate between hail and rain. Local ground-based hail sensors are much better at detecting hail against a rain background, and when incorporated with radar data, provide a much better local picture of a severe rain or hail event. The previous disdrometer interpolation/ extrapolation algorithm described a method to interpolate horizontally between multiple ground sensors (a minimum of three) and extrapolate vertically. This work is a modification to that approach that generates a purely extrapolated 3D spatial distribution when using a single sensor.

Lane, John

2013-01-01

62

Surface dose measurement using TLD powder extrapolation  

International Nuclear Information System (INIS)

Surface/near-surface dose measurements in therapeutic x-ray beams are important in determining the dose to the dermal and epidermal skin layers during radiation treatment. Accurate determination of the surface dose is a difficult but important task for proper treatment of patients. A new method of measuring surface dose in phantom through extrapolation of readings from various thicknesses of thermoluminescent dosimeter (TLD) powder has been developed and investigated. A device was designed, built, and tested that provides TLD powder thickness variation to a minimum thickness of 0.125 mm. Variations of the technique have been evaluated to optimize precision with consideration of procedural ease. Results of this study indicate that dose measurements (relative to Dmax) in regions of steep dose gradient in the beam axis direction are possible with a precision (2 standard deviations [SDs]) as good as ± 1.2% using the technique. The dosimeter was developed and evaluated using variation to the experimental method. A clinically practical procedure was determined, resulting in measured surface dose of 20.4 ± 2% of the Dmax dose for a 10 x 10 cm2, 80-cm source-to-surface distance (SSD), Theratron 780 Cobalt-60 (60C) beam. Results obtained with TLD powder extrapolation compare favorably to other methods presented in the literature. The TLD powder extrapolation tool has been used clinically at the Northwestern Ontario Regional Cancer he Northwestern Ontario Regional Cancer Centre (NWORCC) to measure surface dose effects under a number of conditions. Results from these measurements are reported. The method appears to be a simple and economical tool for surface dose measurement, particularly for facilities with TLD powder measurement capabilities

63

Study of the reaction ?-p ? ?-?0 p at 2.77 GeV/c for low momentum transfer of the proton. Application to the Chew-Low extrapolation method for the ?-?0 elastic scattering  

International Nuclear Information System (INIS)

Study of the reaction ?-p ? ?-?0 p at 2.77 GeV/c carried out in the CERN 2 meter large liquid hydrogen bubble chamber at the proton synchrotron, shows that 70 per cent of this reaction goes through ?-p ? ?-p channel. The high statistics allow us to specify the mass and the width of the ?- resonance. In other hand, if the ?- production parameters are independent of the ?- width, it is not the same case for the decay parameters. In the second part, the Chew-Low extrapolation method allows us to determine the ?-?0 elastic cross section to the pole, and the phase shifts of the P waves in the isospin 1 state and S waves in the isospin 2 state. (author)

64

Richardson-extrapolated sequential splitting and its application  

Science.gov (United States)

During numerical time integration, the accuracy of the numerical solution obtained with a given step size often proves unsatisfactory. In this case one usually reduces the step size and repeats the computation, while the results obtained for the coarser grid are not used. However, we can also combine the two solutions and obtain a better result. This idea is based on the Richardson extrapolation, a general technique for increasing the order of an approximation method. This technique also allows us to estimate the absolute error of the underlying method. In this paper we apply Richardson extrapolation to the sequential splitting, and investigate the performance of the resulting scheme on several test examples.

Faragó, István; Havasi, Ágnes; Zlatev, Zahari

2009-04-01

65

Chiral extrapolation beyond the power-counting regime  

International Nuclear Information System (INIS)

Chiral effective field theory can provide valuable insight into the chiral physics of hadrons when used in conjunction with nonperturbative schemes such as lattice quantum chromodynamics (QCD). In this discourse, the attention is focused on extrapolating the mass of the ? meson to the physical pion mass in quenched QCD. With the absence of a known experimental value, this serves to demonstrate the ability of the extrapolation scheme to make predictions without prior bias. By using extended effective field theory developed previously, an extrapolation is performed using quenched lattice QCD data that extends outside the chiral power-counting regime. The method involves an analysis of the renormalization flow curves of the low-energy coefficients in a finite-range regularized effective field theory. The analysis identifies an optimal regularization scale, which is embedded in the lattice QCD data themselves. This optimal scale is the value of the regularization scale at which the renormalization of the low-energy coefficients is approximately independent of the range of quark masses considered. By using recent precision, quenched lattice results, the extrapolation is tested directly by truncating the analysis to a set of points above 380 MeV, while temporarily disregarding the simulation results closer to the chiral regime. This tests the ability of the method to make predictions of the simulation results, without phenomenologically motivated bias. The result is a succally motivated bias. The result is a successful extrapolation to the chiral regime.

66

An extrapolation of radionuclide retention data from mouse to man  

International Nuclear Information System (INIS)

Previous extrapolations of radionuclide retention data from animals to man have involved the use of data obtained from three to four animal species where each radionuclide was administered and a power function model was used to fit the data. A ''similarity ratio'' method has been developed whereby only data obtained from mice or rats could be used to extrapolate to humans so metabolic testing of many radionuclides in more than one species may be circumvented. Even though the focus of this paper is to provide a more cost-effective way to project radionuclide retention data from mouse to man, the rationale presented could result in a useful way to extrapolate other endpoint results in radiobiology. (author)

67

Extrapolations of nuclear binding energies from new linear mass relations  

DEFF Research Database (Denmark)

We present a method to extrapolate nuclear binding energies from known values for neighboring nuclei. We select four specific mass relations constructed to eliminate smooth variation of the binding energy as function nucleon numbers. The fast odd-even variations are avoided by comparing nuclei with same parity. The mass relations are first tested and shown to either be rather accurately obeyed or revealing signatures of quickly varying structures. Extrapolations are initially made for a nucleus by applying each of these relations. Very reliable estimates are then produced either by an average or by choosing the extrapolation where the smoothest structures enter. Corresponding mass relations for Q? values are used to study the general structure of superheavy elements. A minor neutron shell at N=152 is seen, but no sign of other shell structures are apparent in the superheavy region. Accuracies are typically substantially better than 0.5 MeV.

Hove, D.; Jensen, A. S.

2013-01-01

68

A new approach for stress rupture data extrapolation  

International Nuclear Information System (INIS)

The common feature of stress rupture lines in the usual log ?/log tsub(f) - plot is that their curvature is always d2log ?/d(logtsub(f)2<0. Hence, a linear extrapolation from these graphs leads to non-conservative estimates. In the present investigation it is shown that stress rupture functions F(?,tsub(f)) can be derived which are more suitable for life time extrapolations as the usual one mentioned above. Best results were obtained with a function of the type tsub(f) approx.sinh ??. Besides a better extrapolation, the functions examined allow a better understanding about the nature of the life time determining mechanisms. The new method is applied to stress rupture data of SS AISI 304. (author)

69

Extrapolations of nuclear binding energies from new linear mass relations  

CERN Document Server

We present a method to extrapolate nuclear binding energies from known values for neighbouring nuclei. We select four specific mass relations constructed to eliminate smooth variation of the binding energy as function nucleon numbers. The fast odd-even variations are avoided by comparing nuclei with same parity. The mass relations are first tested and shown to either be rather accurately obeyed or revealing signatures of quickly varying structures. Extrapolations are initially made for a nucleus by applying each of these relations. Very reliable estimates are then produced either by an average or by choosing the extrapolation where the smoothest structures enter. Corresponding mass relations for $Q_{\\alpha}$ values are used to study the general structure of super-heavy elements. A minor neutron shell at $N = 152$ is seen, but no sign of other shell structures are apparent in the super-heavy region. Accuracies are typically substantially better than $0.5$~MeV.

Hove, D; Riisager, K

2014-01-01

70

Fuzzy Model Comparison to Extrapolate Rainfall Data  

Directory of Open Access Journals (Sweden)

Full Text Available This research presents two fuzzy rule-based models for extrapolating the missing rainfall data records of a station, utilizing as a reference the values from another meteorological station located in an adjacent area. The first one is constructed based on the least squares algorithm and the second one using ANFIS method. Three stations were used in this research, all located in Northern Greece. The values of Thessaloniki station were used as fuzzy premises and the values of Sindos and Kria Vrisi were used as fuzzy responses. The model performance was measured by testing several types and numbers of membership functions. Both models are compared with the classical method of linear regression. The comparison between the classical and fuzzy logic method, shows that the second one performs better in recovering the missing rainfall values. It was also found that a fuzzy rule based system, trained with the least squares algorithm, with two fully overlapping fuzzy numbers, is identical to the linear regression method.

C. Tzimopoulos

2008-01-01

71

Design and building of an extrapolation ionization chamber for beta dosimetry  

International Nuclear Information System (INIS)

An extrapolation chamber was designed and built to be used in beta dosimetry. The basic characteristics of an extrapolation chamber are discussed, together with fundamental principle of the dosimetric method used. Details of the chamber's design and properties of materials employed are presented. A full evaluation of extrapolation chamber under irradiation from two 90Sr + 90Y beta sources is done. The geometric parameters of the chamber, leakage current and ion collection efficiency are determined. (Author)

72

Outlier robustness for wind turbine extrapolated extreme loads  

DEFF Research Database (Denmark)

Methods for extrapolating extreme loads to a 50 year probability of exceedance, which display robustness to the presence of outliers in simulated loads data set, are described. Case studies of isolated high extreme out-of-plane loads are discussed to emphasize their underlying physical reasons. Stochastic identification of numerical artifacts in simulated loads is demonstrated using the method of principal component analysis. The extrapolation methodology is made robust to outliers through a weighted loads approach, whereby the eigenvalues of the correlation matrix obtained using the loads with its dependencies is utilized to estimate a probability for the largest extreme load to occur at a specific mean wind speed. This inherently weights extreme loads that occur frequently within mean wind speed bins higher than isolated occurrences of extreme loads. Primarily, the results for the blade root out-of-plane loads are presented here as those extrapolated loads have shown wide variability in literature, but the method can be generalized to any other component load. The convergence of the 1 year extrapolated extreme blade root out-of-plane load with the number of turbulent wind samples used in the loads simulation is demonstrated and compared with published results. Further effects of varying wind inflow angles and shear exponent is brought out. Parametric fitting techniques that consider all extreme loads including ‘outliers’ are proposed, and the physical reasons that result in isolated high extreme loads are highlighted, including the effect of the wind turbine controls system. Copyright © 2011 John Wiley & Sons, Ltd.

Natarajan, Anand; Verelst, David Robert

2012-01-01

73

Prediction of long term stability by extrapolation  

CERN Document Server

This paper studies the possibility of using the survival function to predict long term stability by extrapolation. The survival function is a function of the initial coordinates and is the number of turns a particle will survive for a given set of initial coordinates. To determine the difficulties in extrapolating the survival function, tracking studies were done to compute the survival function. The survival function was found to have two properties that may cause difficulties in extrapolating the survival function. One is the existence of rapid oscillations, and the second is the existence of plateaus. It was found that it appears possible to extrapolate the survival function to estimate long term stability by taking the two difficulties into account. A model is proposed which pictures the survival function to be a series of plateaus with rapid oscillations superimposed on the plateaus. The tracking studies give results for the widths of these plateaus and for the seperation between adjacent plateaus which ...

Parzen, G

2000-01-01

74

Extrapolation Algorithms for Infrared Divergent Integrals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes applications of extrapolation for the computation of coefficients in an expansion of infrared divergent integrals. An extrapolation procedure is performed with respect to a parameter introduced by dimensional regularization. While this treats typical IR singularities at the boundaries of the integration domain, special care needs to be taken in cases where the integrand is singular in the interior of the domain as well as on the boundaries. A double extr...

Doncker, Elise; Fujimoto, Junpei; Hamaguchi, Nobuyuki; Ishikawa, Tadashi; Kurihara, Yoshimasa; Ljucovic, Marko; Shimizu, Yoshimitsu; Yuasa, Fukuko

2011-01-01

75

Frequency extrapolation by nonconvex compressive sensing  

Energy Technology Data Exchange (ETDEWEB)

Tomographic imaging modalities sample subjects with a discrete, finite set of measurements, while the underlying object function is continuous. Because of this, inversion of the imaging model, even under ideal conditions, necessarily entails approximation. The error incurred by this approximation can be important when there is rapid variation in the object function or when the objects of interest are small. In this work, we investigate this issue with the Fourier transform (FT), which can be taken as the imaging model for magnetic resonance imaging (MRl) or some forms of wave imaging. Compressive sensing has been successful for inverting this data model when only a sparse set of samples are available. We apply the compressive sensing principle to a somewhat related problem of frequency extrapolation, where the object function is represented by a super-resolution grid with many more pixels than FT measurements. The image on the super-resolution grid is obtained through nonconvex minimization. The method fully utilizes the available FT samples, while controlling aliasing and ringing. The algorithm is demonstrated with continuous FT samples of the Shepp-Logan phantom with additional small, high-contrast objects.

Chartrand, Rick [Los Alamos National Laboratory; Sidky, Emil Y [UNIV OF CHICAGO; Pan, Xiaochaun [UNIV OF CHICAGO

2010-12-03

76

Frequency extrapolation by nonconvex compressive sensing  

International Nuclear Information System (INIS)

Tomographic imaging modalities sample subjects with a discrete, finite set of measurements, while the underlying object function is continuous. Because of this, inversion of the imaging model, even under ideal conditions, necessarily entails approximation. The error incurred by this approximation can be important when there is rapid variation in the object function or when the objects of interest are small. In this work, we investigate this issue with the Fourier transform (FT), which can be taken as the imaging model for magnetic resonance imaging (MRl) or some forms of wave imaging. Compressive sensing has been successful for inverting this data model when only a sparse set of samples are available. We apply the compressive sensing principle to a somewhat related problem of frequency extrapolation, where the object function is represented by a super-resolution grid with many more pixels than FT measurements. The image on the super-resolution grid is obtained through nonconvex minimization. The method fully utilizes the available FT samples, while controlling aliasing and ringing. The algorithm is demonstrated with continuous FT samples of the Shepp-Logan phantom with additional small, high-contrast objects.

77

A dimensional extrapolation technique for ITER  

International Nuclear Information System (INIS)

A novel methodology for extrapolation of the performance of ITER class machines is introduced. This procedure utilizes the ITER ELMy H mode database by means of a similarity approach where every discharge is extrapolated to a machine satisfying the ITER performance requirements through the use of the tokamak system code developed during the course of the ITER design evolution. This approach attempts, amongst other things, to overcome the difficulty associated with the simultaneous choice of non-dimensional parameters which, in particular when close to their respective limits, may have some significant mutual interactions affecting energy confinement time. The methodology is also applied to the ITER Physics Basis scalings to develop a non-statistical approach where fusion power is extrapolated at constant beta and confinement is assumed to follow a gyroBohm form. In both cases, out of more than a thousand discharges in the ELMy H mode database, less than half turn out to extrapolate to a Q = 10 machine whose major radius is smaller than 8 m. However, a significant number of discharges do extrapolate to a Q 10 machine with R < 6.2 m. This strengthens confidence in the present choice of ITER parameters. In addition, from this analysis, it has been possible to identify a set of high performance 'ITER relevant' discharges from a number of machines, which could be used as starting points for investigation of further improvements in confinement. (author)confinement. (author)

78

Data extrapolation techniques for energy systems planning  

Energy Technology Data Exchange (ETDEWEB)

This paper first reviews energy planning problems in India at different levels (all India/Rural India/State/District/Block/Village). It surveys the energy scene in rural areas of the Wardha District for applicational study. It deals with the newly proposed statistical extrapolation technique of either moving first from the village level energy scenario to the corresponding block level energy scenario and then from the block level energy scenarios to the district/region level energy profile. It shows how the model is suitably scaled for obtaining the optimal mix of energy resources and technologies for the Wardha District using a computer based mixed integer/linear programming technique. The average absolute % error is calculated between the actual district/region level energy scenario and the statistical projected (extrapolated) district/region level energy scenario to guage the goodness of fit of the proposed statistical extrapolation technique. (Author)

Malik, S.B. [Indian Inst. of Tech., Centre for Atmospheric Sciences, New Delhi (India); Satsangi, P.S. [Dayalbagh Engineering Coll., Agra (India)

1997-12-31

79

Extrapolation Algorithms for Infrared Divergent Integrals  

CERN Document Server

This paper describes applications of extrapolation for the computation of coefficients in an expansion of infrared divergent integrals. An extrapolation procedure is performed with respect to a parameter introduced by dimensional regularization. While this treats typical IR singularities at the boundaries of the integration domain, special care needs to be taken in cases where the integrand is singular in the interior of the domain as well as on the boundaries. A double extrapolation is devised for a class of massless vertex integrals. Quadruple precision results are presented, demonstrating high accuracy. The computations are supported by the use of general adaptive integration programs from the QUADPACK package, in iterated integrations with highly singular integrand functions.

de Doncker, Elise; Hamaguchi, Nobuyuki; Ishikawa, Tadashi; Kurihara, Yoshimasa; Ljucovic, Marko; Shimizu, Yoshimitsu; Yuasa, Fukuko

2011-01-01

80

Methodology for extrapolation of rock mass deformability parameters in tunneling  

Directory of Open Access Journals (Sweden)

Full Text Available This article proposes one approach for extrapolation of necessary parameters for numerical analyses in tunnelling. The approach is named as an empirical - statical - dynamical method for extrapolation. The proposed methodology is based on combination of empirical classification rock mass methods, geophysical measurements and direct dilatometer deformability testing on a field. The analyses are prepared for purposes of investigation and design for several tunnels in Republic of Macedonia. One example for dividing of tunnel length in quasi-homogenous zones, as a basis for forming of geotechnical and numerical model that can be a basis for interaction analyses of rock - structures system and stress-strain behaviour of rock massif, is also given. The several original regressive models between rock mass quality, deformability and velocity of longitudinal seismic waves are shown.

Zafirovski Zlatko

2012-01-01

 
 
 
 
81

EXTRAPOLATING BRAIN DEVELOPMENT FROM EXPERIMENTAL SPECIES TO HUMANS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To better understand the neurotoxic effects of diverse hazards on the developing human nervous system, researchers and clinicians rely on data collected from a number of model species that develop and mature at varying rates. We review the methods commonly used to extrapolate the timing of brain development from experimental mammalian species to humans, including morphological comparisons, “rules of thumb” and “event-based” analyses. Most are unavoidably limited in range or detail, ma...

Clancy, Barbara; Finlay, Barbara L.; Darlington, Richard B.; Anand, Kjs

2007-01-01

82

COMPUTERIZED EXTRAPOLATION OF HYDROLYSIS RATE DATA  

Science.gov (United States)

The program RATE was developed to aid in the extrapolation and interpretation of hydrolysis rate data to a format that is useful for environmental risk assessment. ydrolysis data typically are reported in the literature as pseudo-first-order rate constants at the temperature and ...

83

Issues and current applications of interspecies extrapolation of carcinogenic potency as a component of risk assessment.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Life Sciences Research Office (LSRO) of the Federation of American Societies for Experimental Biology (FASEB) is conducting this symposium under contract with the Center for Food Safety and Applied Nutrition (CFSAN) of the Food and Drug Administration (FDA). The FDA has requested information on the strengths and weaknesses of current interspecies extrapolation methods using metabolic and pharmacokinetic data, identity of data for these methods, bases for choice of extrapolation method and...

Visek, W. J.

1988-01-01

84

National pattern for the realization of the unit of the dose speed absorbed in air for beta radiation. (Method: Ionometer, cavity of Bragg-Gray implemented in an extrapolation chamber with electrodes of variable separation, exposed to a field of beta radiation of 90Sr/90Y)  

International Nuclear Information System (INIS)

From the year of 1987 the Department of Metrology of the ININ, in their Secondary Laboratory of Calibration Dosimetric, has a patron group of sources of radiation beta and an extrapolation chamber of electrodes of variable separation.Their objective is to carry out of the unit of the dose speed absorbed in air for radiation beta. It uses the ionometric method, cavity Bragg-Gray in the extrapolation chamber with which it counts. The services that offers are: i) it Calibration : Radioactive Fuentes of radiation beta, isotopes: 90Sr/90Y; Ophthalmic applicators 90Sr/90Y; Instruments for detection of beta radiation with to the radiological protection: Ionization chambers, Geiger-Muller, etc.; Personal Dosemeters. ii) Irradiation with beta radiation of materials to the investigation. (Author)

85

Analysis of ?-p ? ?-p, ?-p ? ?-?0p et ?-p ? ?+?-n reactions at 2,77 GeV/c and study of the ?? elastic scattering by the Chew-Low extrapolation method applied to ?-p ? ?-?0p and ?-p ? ?+?-n reactions  

International Nuclear Information System (INIS)

180000 pictures taken in the 2 m CERN hydrogen bubble chamber with an incident beam of 2.77 GeV/e were examined. High statistics obtained in the whole angular production range allowed to study the d?/dt differential cross section behaviour, the mass and width of the ? meson, and the multipole parameters of this resonance. Nevertheless, the aim of this experiment was the application of the CHEW - LOW extrapolation method. Different types of extrapolation procedures were compared. Phase shift analysis of the elastic ?? scattering between 500 and 1100 MeV, performed with conformal mappings, allowed to determine the values of the S0, S2, P1, D0, D2 waves. Forward dispersion relations were used to obtain scattering length values of the S2 and P1 phase shifts. (author)

86

Response Load Extrapolation for Wind Turbines during Operation Based on Average Conditional Exceedance Rates  

DEFF Research Database (Denmark)

The paper explores a recently developed method for statistical response load (load effect) extrapolation for application to extreme response of wind turbines during operation. The extrapolation method is based on average conditional exceedance rates and is in the present implementation restricted to cases where the Gumbel distribution is the appropriate asymptotic extreme value distribution. However, two extra parameters are introduced by which a more general and flexible class of extreme value distributions is obtained with the Gumbel distribution as a subclass. The general method is implemented within a hierarchical model where the variables that influence the loading are divided into ergodic variables and time-invariant non-ergodic variables. The presented method for statistical response load extrapolation was compared with the existing methods based on peak extrapolation for the blade out-of-plane bending moment and the tower mudline bending moment of a pitch-controlled wind turbine. In general, the results show that the method based on average conditional exceedance rates predicts the extrapolated characteristic response loads at the individual mean wind speeds well and results in more consistent estimates than the methods based on peak extrapolation.

Toft, Henrik Stensgaard; Naess, Arvid

2011-01-01

87

Effective Orthorhombic Anisotropic Models for Wave field Extrapolation  

Wavefield extrapolation in orthorhombic anisotropic media incorporates complicated but realistic models, to reproduce wave propagation phenomena in the Earth\\'s subsurface. Compared with the representations used for simpler symmetries, such as transversely isotropic or isotropic, orthorhombic models require an extended and more elaborated formulation that also involves more expensive computational processes. The acoustic assumption yields more efficient description of the orthorhombic wave equation that also provides a simplified representation for the orthorhombic dispersion relation. However, such representation is hampered by the sixth-order nature of the acoustic wave equation, as it also encompasses the contribution of shear waves. To reduce the computational cost of wavefield extrapolation in such media, I generate effective isotropic inhomogeneous models that are capable of reproducing the first-arrival kinematic aspects of the orthorhombic wavefield. First, in order to compute traveltimes in vertical orthorhombic media, I develop a stable, efficient and accurate algorithm based on the fast marching method. The derived orthorhombic acoustic dispersion relation, unlike the isotropic or transversely isotropic one, is represented by a sixth order polynomial equation that includes the fastest solution corresponding to outgoing P-waves in acoustic media. The effective velocity models are then computed by evaluating the traveltime gradients of the orthorhombic traveltime solution, which is done by explicitly solving the isotropic eikonal equation for the corresponding inhomogeneous isotropic velocity field. The inverted effective velocity fields are source dependent and produce equivalent first-arrival kinematic descriptions of wave propagation in orthorhombic media. I extrapolate wavefields in these isotropic effective velocity models using the more efficient isotropic operator, and the results compare well, especially kinematically, with those obtained from the more expensive anisotropic extrapolator.

Ibanez Jacome, Wilson

2013-05-01

88

Extrapolation of toxic indices among test objects  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Oligochaeta Tubifex tubifex, fish fathead minnow (Pimephales promelas), hepatocytes isolated from rat liver and ciliated protozoan are absolutely different organisms and yet their acute toxicity indices correlate. Correlation equations for special effects were developed for a large heterogeneous series of compounds (QSAR, quantitative structure-activity relationships). Knowing those correlation equations and their statistic evaluation, one can extrapolate the toxic indices. The reason is that...

Tichy?, Milon?; Rucki, Maria?n; Roth, Zdene?k; Hanzli?kova?, Iveta; Vlkova?, Alena; Tumova?, Jana; Uzlova?, Ru?t

2010-01-01

89

In situ LTE exposure of the general public: Characterization and extrapolation.  

Science.gov (United States)

In situ radiofrequency (RF) exposure of the different RF sources is characterized in Reading, United Kingdom, and an extrapolation method to estimate worst-case long-term evolution (LTE) exposure is proposed. All electric field levels satisfy the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels with a maximal total electric field value of 4.5 V/m. The total values are dominated by frequency modulation (FM). Exposure levels for LTE of 0.2 V/m on average and 0.5 V/m maximally are obtained. Contributions of LTE to the total exposure are limited to 0.4% on average. Exposure ratios from 0.8% (LTE) to 12.5% (FM) are obtained. An extrapolation method is proposed and validated to assess the worst-case LTE exposure. For this method, the reference signal (RS) and secondary synchronization signal (S-SYNC) are measured and extrapolated to the worst-case value using an extrapolation factor. The influence of the traffic load and output power of the base station on in situ RS and S-SYNC signals are lower than 1 dB for all power and traffic load settings, showing that these signals can be used for the extrapolation method. The maximal extrapolated field value for LTE exposure equals 1.9 V/m, which is 32 times below the ICNIRP reference levels for electric fields. PMID:22271226

Joseph, Wout; Verloock, Leen; Goeminne, Francis; Vermeeren, Günter; Martens, Luc

2012-09-01

90

Extrapolation of Fracture Toughness Data for HT9 Irradiated at Temperatures 360-390 C  

International Nuclear Information System (INIS)

The objective of this task is to provide estimated HT9 cladding and duct fracture toughness values for test (or application) temperatures ranging from -10 C to 200 C, after irradiation at temperatures of 360-390 C. This is expected to be an extrapolation of the limited data presented by Huang(1, 2). This extrapolation is based on currently accepted methods (ASTM 2003 Standard E 1921-02), and other relevant fracture toughness data on irradiated HT9 or similar alloys

91

Extrapolation of Calibration Curve of Hot-wire Spirometer Using a Novel Neural Network Based Approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hot-wire spirometer is a kind of constant temperature anemometer (CTA). The working principle of CTA, used for the measurement of fluid velocity and flow turbulence, is based on convective heat transfer from a hot-wire sensor to a fluid being measured. The calibration curve of a CTA is nonlinear and cannot be easily extrapolated beyond its calibration range. Therefore, a method for extrapolation of CTA calibration curve will be of great practical application. In this paper, a novel approach b...

Ardekani, Mohammad Ali; Nafisi, Vahid Reza; Farhani, Foad

2012-01-01

92

On extrapolation blowups in the scale  

Directory of Open Access Journals (Sweden)

Full Text Available Yano's extrapolation theorem dated back to 1951 establishes boundedness properties of a subadditive operator acting continuously in for close to and/or taking into as and/or with norms blowing up at speed and/or , . Here we give answers in terms of Zygmund, Lorentz-Zygmund and small Lebesgue spaces to what happens if as . The study has been motivated by current investigations of convolution maximal functions in stochastic analysis, where the problem occurs for . We also touch the problem of comparison of results in various scales of spaces.

Fiorenza Alberto

2006-01-01

93

Extrapolation of hydrogen molar volumes by the virial equation on wide pressure and temperature intervals  

International Nuclear Information System (INIS)

A virial equation was used for approximation of experimental molar volumes at high and low pressures for experimental temperatures. It was shown that the virial equation can be used for wide pressure and temperature intervals in distinction of the Tait, logarithm and other equations. The obtained under fitting of experimental data virial parameters were used for their following extrapolations on wide temperature intervals. The direct solution of the third order linear virial equations relative to molar volumes using the Kardano or Newton methods was employed for extrapolation of experimental dependences from high pressure to low pressure and from low pressure to high and superhigh pressures. A quite good agreement between experimental values of molar volumes versus pressures and extrapolating ones allows one to conclude that for a definite temperature interval with high probability and proof it is possible to make extrapolations on superhigh pressures

94

Extrapolation of Extreme Response for Wind Turbines based on FieldMeasurements  

DEFF Research Database (Denmark)

The characteristic loads on wind turbines during operation are among others dependent on the mean wind speed, the turbulence intensity and the type and settings of the control system. These parameters must be taken into account in the assessment of the characteristic load. The characteristic load is normally determined by statistical extrapolation of the simulated response during operation according to IEC 61400-1 2005. However, this method assumes that the individual 10 min. time series are independent and that peaks extracted are independent. In the present paper two new methods for loads extrapolation are presented. The first method is based on the same assumptions as the existing method but the statistical extrapolation is only performed for a limited number of mean wind speeds where the extreme load is likely to occur. For the second method the mean wind speeds are divided into storms which are assumed independent and the characteristic loads are determined from the extreme load in each storm.

Toft, Henrik Stensgaard; SØrensen, John Dalsgaard

2009-01-01

95

Universal properties of infrared oscillator basis extrapolations  

CERN Document Server

Recent work has shown that a finite harmonic oscillator basis in nuclear many-body calculations effectively imposes a hard-wall boundary condition in coordinate space, motivating infrared extrapolation formulas for the energy and other observables. Here we further refine these formulas by studying two-body models and the deuteron. We accurately determine the box size as a function of the model space parameters, and compute scattering phase shifts in the harmonic oscillator basis. We show that the energy shift can be well approximated in terms of the asymptotic normalization coefficient and the bound-state momentum, discuss higher-order corrections for weakly bound systems, and illustrate this universal property using unitarily equivalent calculations of the deuteron.

More, S N; Furnstahl, R J; Hagen, G; Papenbrock, T

2013-01-01

96

Scintillation counting: an extrapolation into the future  

International Nuclear Information System (INIS)

Progress in scintillation counting is intimately related to advances in a variety of other disciplines such as photochemistry, photophysics, and instrumentation. And while there is steady progress in the understanding of luminescent phenomena, there is a virtual explosion in the application of semiconductor technology to detectors, counting systems, and data processing. The exponential growth of this technology has had, and will continue to have, a profound effect on the art of scintillation spectroscopy. This paper will review key events in technology that have had an impact on the development of scintillation science (solid and liquid) and will attempt to extrapolate future directions based on existing and projected capability in associated fields. Along the way there have been occasional pitfalls and several false starts; these too will be discussed as a reminder that if you want the future to be different than the past, study the past

97

Cosmological extrapolation of modified Newtonian dynamics  

International Nuclear Information System (INIS)

The regime of modified Newtonian dynamics (MOND), which is used in astronomy to describe gravitating systems of the island type without the need to postulate the existence of a hypothetical dark matter, is generalized to the case of homogeneous distribution of usual matter by introducing a linear dependence of the critical acceleration on the size of the region under consideration. We show that such an extrapolation of MOND in cosmology is consistent with both the observed dependence of brightness on the redshift for type Ia supernovae and the parameters of large-scale structure of the evolving Universe, that are determined by the presence of a cosmological constant, the ordinary matter of baryons and electrons, and photon and neutrino radiation, without any dark matter. (paper)

98

Ultraviolet extrapolations in finite oscillator bases  

Science.gov (United States)

The use of finite harmonic oscillator spaces in many-body calculations introduces both infrared (IR) and ultraviolet (UV) errors. The IR effects are well approximated by imposing a hard-wall boundary condition at a properly identified radius Leff. We show that duality of the oscillator implies that the UV effects are equally well described by imposing a sharp momentum cutoff at a momentum ?eff complementary to Leff. By considering two-body systems with separable potentials, we show that the UV energy corrections depend on details of the potential, in contrast to the IR energy corrections, which depend only on the S -matrix. An adaptation of the separable treatment to more general interactions is developed and applied to model potentials as well as to the deuteron with realistic potentials. The previous success with a simple phenomenological form for the UV error is also explained. Possibilities for controlled extrapolations for A >2 based on scaling arguments are discussed.

König, S.; Bogner, S. K.; Furnstahl, R. J.; More, S. N.; Papenbrock, T.

2014-12-01

99

Cosmological extrapolation of modified Newtonian dynamics  

Science.gov (United States)

The regime of modified Newtonian dynamics (MOND), which is used in astronomy to describe gravitating systems of the island type without the need to postulate the existence of a hypothetical dark matter, is generalized to the case of homogeneous distribution of usual matter by introducing a linear dependence of the critical acceleration on the size of the region under consideration. We show that such an extrapolation of MOND in cosmology is consistent with both the observed dependence of brightness on the redshift for type Ia supernovae and the parameters of large-scale structure of the evolving Universe, that are determined by the presence of a cosmological constant, the ordinary matter of baryons and electrons, and photon and neutrino radiation, without any dark matter.

Kiselev, V. V.; Timofeev, S. A.

2012-03-01

100

Towards a Thomas-Fermi mass formula for extrapolation to the neutron-drip line  

International Nuclear Information System (INIS)

For an analysis of the r-process of stellar nucleosynthesis, binding energies of the unknown nuclei close to the neutron drip line are required. The way to get these energies is to use the nuclear mass formula to extrapolate from the known nuclei to the unknown nuclei close to the neutron-drip line. It is observed that the mass formulas based on existing forms of the droplet model (DM) extrapolate very badly out to the neutron-drip line, but a mass formula based on the Extended Thomas-Fermi (ETF) method with Skyrme-type force extrapolates out to the neutron-drip line almost as well as the Hartree-Fock (HF) method and is computationally much faster than HF method. (M.G.B.)

 
 
 
 
101

Ultraviolet extrapolations in finite oscillator bases  

CERN Document Server

The use of finite harmonic oscillator spaces in many-body calculations introduces both infrared (IR) and ultraviolet (UV) errors. The IR effects are well approximated by imposing a hard-wall boundary condition at a properly identified radius L_eff. We show that duality of the oscillator implies that the UV effects are equally well described by imposing a sharp momentum cutoff at a momentum Lambda_eff complementary to L_eff. By considering two-body systems with separable potentials, we show that the UV energy corrections depend on details of the potential, in contrast to the IR energy corrections, which depend only on the S-matrix. An adaptation of the separable treatment to more general interactions is developed and applied to model potentials as well as to the deuteron with realistic potentials. The previous success with a simple phenomenological form for the UV error is also explained. Possibilities for controlled extrapolations for A > 2 based on scaling arguments are discussed.

König, S; Furnstahl, R J; More, S N; Papenbrock, T

2014-01-01

102

Hard hadronic collisions: extrapolation of standard effects  

International Nuclear Information System (INIS)

We study hard hadronic collisions for the proton-proton (pp) and the proton-antiproton (p anti p) option in the CERN LEP tunnel. Based on our current knowledge of hard collisions at the present CERN p anti p Collider, and with the help of quantum chromodynamics (QCD), we extrapolate to the next generation of hadron colliders with a centre-of-mass energy E/sub cm/ = 10 to 20 TeV. We estimate various signatures, trigger rates, event topologies, and associated distributions for a variety of old and new physical processes, involving prompt photons, leptons, jets, W+- and Z bosons in the final state. We also calculate the maximum fermion and boson masses accessible at the LEP Hadron Collider. The standard QCD and electroweak processes studied here, being the main body of standard hard collisions, quantify the challenge of extracting new physics with hadron colliders. We hope that our estimates will provide a useful profile of the final states, and that our experimental physics colleagues will find this of use in the design of their detectors. 84 references

103

Hard hadronic collisions: extrapolation of standard effects  

Energy Technology Data Exchange (ETDEWEB)

We study hard hadronic collisions for the proton-proton (pp) and the proton-antiproton (p anti p) option in the CERN LEP tunnel. Based on our current knowledge of hard collisions at the present CERN p anti p Collider, and with the help of quantum chromodynamics (QCD), we extrapolate to the next generation of hadron colliders with a centre-of-mass energy E/sub cm/ = 10 to 20 TeV. We estimate various signatures, trigger rates, event topologies, and associated distributions for a variety of old and new physical processes, involving prompt photons, leptons, jets, W/sup + -/ and Z bosons in the final state. We also calculate the maximum fermion and boson masses accessible at the LEP Hadron Collider. The standard QCD and electroweak processes studied here, being the main body of standard hard collisions, quantify the challenge of extracting new physics with hadron colliders. We hope that our estimates will provide a useful profile of the final states, and that our experimental physics colleagues will find this of use in the design of their detectors. 84 references.

Ali, A.; Aurenche, P.; Baier, R.; Berger, E.; Douiri, A.; Fontannaz, M.; Humpert, B.; Ingelman, G.; Kinnunen, R.; Pietarinen, E.

1984-01-01

104

A physically based methodology to extrapolate performance maps of radial turbines  

International Nuclear Information System (INIS)

Highlights: ? Physical based methodology to extrapolate radial turbine efficiency measured data. ? Equation relating efficiency versus blade to speed ratio (?) have been developed. ? Developed efficiency equation takes into account turbine mass flow parameter. ? Efficiency versus ? at constant pressure ratio is discussed, also at constant speed. ? The methodology has been validated with a broad range of experimental results. - Abstract: This paper details a physically based methodology to perform an extrapolation of the radial turbine performance maps, both mass flow characteristics and the efficiency curve. This method takes into account a narrow range of experimental data, which is usually the data available when such turbines are part of a turbocharger. Therefore, the extrapolation methodology is especially useful when data from third parties are being used or when the compressor of a turbocharger is used as the turbine brake in a gas stand. The nozzle equation is used to develop an interpolation and extrapolation of the mass flow rate trough the turbine. Then, specific information is extracted from this extrapolation and is fed into a total-to-static efficiency equation to carry out an extension of the efficiency curve. This equation is developed using the definition of the total-to-static efficiency, velocity triangles and thermodynamic and fluid fundamental equations. This procedure has been applied to five radial turbines of different sizes and typees of different sizes and types. Results are compared against experimental information available in the literature or provided by the turbine manufacturers and a good agreement has been found between theoretical and experimentally estimated data.

105

Slow neutron flux extrapolation distances in R-5 and CIRUS reactors  

International Nuclear Information System (INIS)

In order to calculate the core reactivity, fuel channel power outputs and neutron flux levels in the R-5 reactor at Trombay, axial flux extrapolation distances are required. For this, an analysis is carried out considering the reactor core as a two region neutron multiplying system in axial direction. The slow neutron diffusion equations for both the regions are solved analytically by applying suitable boundary conditions. Application of this method for the estimation of top extrapolation distances in CIRUS, has given results which agree well with accepted values for the reactor. (author)

106

Quark Mass Dependence of Nucleon Properties and Extrapolation from Lattice QCD  

CERN Document Server

We summarize developments concerning the quark mass dependence of nucleon magnetic moments and the axial-vector coupling constant g_A. The aim is to explore the feasibility of chiral effective field theory methods for the extrapolation of lattice QCD results, from the relatively large quark masses that can be handled in such computations down to the physically relevant range.

Hemmert, T R; Weise, W; Hemmert, Thomas R.; Procura, Massimiliano; Weise, Wolfram

2003-01-01

107

Thermal neutron extrapolation distances for slabs of beryllium and water  

International Nuclear Information System (INIS)

Extrapolation distances for thermal neutrons have been obtained for slabs of beryllium and light water by minimising the difference between the steady-state leakage spectra calculated on the basis of diffusion and transport theories. Using the present values of extrapolation distance ensures that neutron spectra (both in beryllium and water) calculated on the basis of diffusion theory agree well with the corresponding transport theory spectra, even at distances close to the free surface. The extrapolation distance is found to be dependent on the thickness of the slab, increasing with increase in the thickness. (author)

108

Binding energies of hydrogen-bonded complexes from extrapolation with localized basis sets  

Science.gov (United States)

By incorporating effective basis sets containing diffuse functions only in the interaction region of hydrogen-bonded complexes into the simple extrapolation scheme suitable for such basis sets, an accurate estimation of the MP2 basis set limit hydrogen-bonding energies of formic acid tetramer, formamide tetramer, alanine-water, phenol-water, and guanine-cytosine base pair is made with all estimates falling within 0.1-0.3kcal/mol of the reference basis set limits. The basis sets for extrapolation are composed of the cc-pVDZ and cc-pVDZ plus highest polarization functions from the cc-pVTZ set, or cc-pVDZ and cc-pVTZ set, all of which are augmented by the diffuse functions of the atoms in the interaction region of hydrogen bond. In contrast to the extrapolated estimates by this method, density functional theory binding energies with B3LYP, B971, and TPSS methods yield the differences from the reference values as large as 3.9kcal/mol with much higher computational cost in most cases, signifying the efficacy of the employed extrapolation scheme for study of large hydrogen-bonded complexes.

Lee, Jae Shin

2007-08-01

109

Role of animal studies in low-dose extrapolation  

International Nuclear Information System (INIS)

Current data indicate that in the case of low-LET radiation linear, extrapolation from data obtained at high doses appears to overestimate the risk at low doses to a varying degree. In the case of high-LET radiation, extrapolation from data obtained at doses as low as 40 rad (0.4 Gy) is inappropriate and likely to result in an underestimate of the risk

110

Extrapolation of mean-field models to superheavy nuclei  

International Nuclear Information System (INIS)

The extrapolation of self-consistent nuclear mean-field models to the region of superheavy elements is discussed with emphasis on the extrapolating power of the models. The predictions of modern mean-field models are confronted with recent experimental data. It is shown that a final conclusion about the location of the expected island of spherical doubly-magic superheavy nuclei cannot be drawn on the basis of the available data. (orig.)

111

Bayesian estimation of medium properties in wavefield downward extrapolation problems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

When acoustic waves are used for nondestructive imaging of the interior of objects such as the Earth the human body, etc., the wavefield measurements recorded on the surface of the object are extrapolated according to the wave equation to give an image of the object. The extrapolation propagates backward the noise present in the measurements, so that the quality of the final image is degraded, unless statistical restoration techniques are used. Another source of degradation of the image is th...

Pitas, I.; Venetsanopoulos, A. N.

2010-01-01

112

Monitoring corrosion and corrosion control of iron in HCl by non-ionic surfactants of the TRITON-X series - Part I. Tafel polarisation, ICP-AES and EFM studies  

Energy Technology Data Exchange (ETDEWEB)

The corrosion inhibition characteristics of non-ionic surfactants of the TRITON-X series, known as TRITON-X-100 (TX-100), TRITON-X-165 (TX-165) and TRITON-X-305 (TX-305), on iron in 1.0 M HCl solution were studied. Measurements were conducted in 1.0 M HCl solutions without and with various concentrations of the three selected surfactants using chemical (ICP-AES method of analysis of dissolved cations) and electrochemical (Tafel polarisation and EFM) techniques at 25 deg. C. These measurements were complemented with SEM and EDX examinations of the electrode surface. Polarisation data showed that the non-ionic surfactants used in this study acted as mixed-type inhibitors with cathodic predominance. The protection efficiency increased with increase in surfactant concentration. Maximum protection efficiency of the surfactant was observed at concentrations around its CMC. From their molecular structure, these surfactants may adsorb on the metal surface through two lone pairs of electrons on the oxygen atoms of the hydrophilic head group.

Amin, Mohammed A. [Materials and Corrosion Lab (MCL), Department of Chemistry, Faculty of Science, Taif University, 888 Haweiah, Taif, KSA (Egypt); Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo (Egypt)], E-mail: maaismail@yahoo.com; Khaled, K.F. [Materials and Corrosion Lab (MCL), Department of Chemistry, Faculty of Science, Taif University, 888 Haweiah, Taif, KSA (Egypt); Electrochemistry Research Laboratory, Chemistry Department, Faculty of Education, Ain Shams University, Roxy, Cairo (Egypt)

2010-05-15

113

Monitoring corrosion and corrosion control of iron in HCl by non-ionic surfactants of the TRITON-X series - Part I. Tafel polarisation, ICP-AES and EFM studies  

International Nuclear Information System (INIS)

The corrosion inhibition characteristics of non-ionic surfactants of the TRITON-X series, known as TRITON-X-100 (TX-100), TRITON-X-165 (TX-165) and TRITON-X-305 (TX-305), on iron in 1.0 M HCl solution were studied. Measurements were conducted in 1.0 M HCl solutions without and with various concentrations of the three selected surfactants using chemical (ICP-AES method of analysis of dissolved cations) and electrochemical (Tafel polarisation and EFM) techniques at 25 deg. C. These measurements were complemented with SEM and EDX examinations of the electrode surface. Polarisation data showed that the non-ionic surfactants used in this study acted as mixed-type inhibitors with cathodic predominance. The protection efficiency increased with increase in surfactant concentration. Maximum protection efficiency of the surfactant was observed at concentrations around its CMC. From their molecular structure, these surfactants may adsorb on the metal surface through two lone pairs of electrons on the oxygen atoms of the hydrophilic head group.

114

Associação de cetamina S(+) e midazolam pelo método convencional de cálculo e pela extrapolação alométrica em bugios-ruivo (Alouatta guariba clamitans): resposta clínica e cardiorrespiratória / S(+) ketamine and midazolam association by the conventional method of calculation and allometric extrapolation in red howler monkeys (Alouatta guariba clamitans): clinical and cardiopulmonary response  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste estudo foi avaliar o protocolo de contenção química com cetamina S(+) e midazolam em bugios-ruivos, comparando o cálculo de doses pelo método convencional e o método de extrapolação alométrica. Foram utilizados 12 macacos bugios (Alouatta guariba clamitans) hígidos, com peso médio d [...] e 4,84±0,97kg, de ambos os sexos. Após jejum alimentar de 12 horas e hídrico de seis horas, realizou-se contenção física manual e aferiram-se os seguintes parâmetros: frequência cardíaca (FC), frequência respiratória (f), tempo de preenchimento capilar (TPC), temperatura retal (TR), pressão arterial sistólica não invasiva (PANI) e valores de hemogasometria arterial. Posteriormente, os animais foram alocados em dois grupos: GC (Grupo Convencional, n=06), os quais receberam cetamina S(+) (5mg kg-1) e midazolam (0,5mg kg-1), pela via intramuscular, com doses calculadas pelo método convencional; e GA (Grupo Alometria, n=06), os quais receberam o mesmo protocolo, pela mesma via, utilizando-se as doses calculadas pelo método de extrapolação alométrica. Os parâmetros descritos foram mensurados novamente nos seguintes momentos: M5, M10, M20 e M30 (cinco, 10, 20 e 30 minutos após a administração dos fármacos, respectivamente). Também foram avaliados: qualidade de miorrelaxamento, reflexo podal e caudal, pinçamento interdigital, tempo para indução de decúbito, tempo hábil de sedação, qualidade de sedação, e tempo e qualidade de recuperação. O GA apresentou menor tempo para indução ao decúbito, maior grau e tempo de sedação, bem como redução significativa da FC e PANI de M5 até M30, quando comparado ao GC. Conclui-se que o grupo no qual o cálculo de dose foi realizado por meio da alometria (GA) apresentou melhor grau de relaxamento muscular e sedação, sem produzir depressão cardiorrespiratória significativa. Abstract in english The aim of this study was to evaluate a protocol of chemical restraint comparing the conventional method of calculation (weight dose) and allometric extrapolation. Twelve healthy red howler monkeys (Alouatta guariba clamitans), average weight 4.84±0.97kg, male and female, were used for this study. A [...] fter a 12-hour period of food restriction and 6 hours of water restriction, the animals were physically restraint and the following parameters were measured: heart rate (HR), respiratory rate (RR), capillary refill time (CRT), rectal temperature (RT), non invasive systolic arterial pressure (NISAP) and arterial blood gases analysis. The animals were distributed into two groups: CG (Conventional Group, n=6), in which the animals received S(+) ketamine (5mg kg-1) and midazolam (0.5mg kg-1), by intramuscular (IM) injection; and AG (Allometry Group, n=6), in which the animals also received S(+) ketamine and midazolan IM, but the doses were calculated by allometric extrapolation. Parameters were evaluated at the following moments: M5, M10, M20 and M30 (5, 10, 20 and 30 minutes after IM injection, respectively). Muscle relaxation, pedal and caudal reflexes, interdigital pinch, recumbency time, sedation's quality and duration, and recovery time and its quality were also evaluated. The AG had a faster time for recumbency, higher period and quality of sedation, and a significantly reduction on HR and SAP from M5 to M30 when compared to CG. It was concluded that allometric extrapolation presented a better muscle relaxation and sedation without significant cardiorespiratory depression.

Joana Aurora Braun, Chagas; Nilson, Oleskovicz; Aury Nunes de, Moraes; Fabíola Niederauer, Flôres; André Luís, Corrêa; Júlio César, Souza Júnior; André Vasconcelos, Soares; Átila, Costa.

2010-02-01

115

Convergence and extrapolation studies with the fit 3D code  

International Nuclear Information System (INIS)

The FIT Code, designed to compute ideal MHD equilibria, was tested on six configurations representative of stellarator research. The code was modified in the following points: 1) The previous iteration mehods were extended by a conjugate gradient method capable of varying all three dependent inverse variables r,z, and ? simultaneously. The non-uniqueness of these variables can be eliminated by appropriate coupling of some of the r- and z-coefficients in the Fourier series. The selected configurations are: 1) an axisymmetric Solov'ev equilibrium, where the energy was computed analytically; 2) an axisymmetric high-beta equilibrium, where, owing to the strong axis shift and the simple circular boundary ?? O is necessary to obtain reasonable numerical solutions at all 3) a low aspect ratio (A ? 4) l = 2 configuration, 4) an ATF model; 5) a W VII-AS; and 6) a Heliac. The results obtained with FIT are presented in detail and compared with those of other codes. The accuracy is checked by two scalars, the energy and the mean axis shift. Because of the radial (s) difference approximations, extrapolation in the mesh-size is necessary

116

Extrapolating brain development from experimental species to humans.  

Science.gov (United States)

To better understand the neurotoxic effects of diverse hazards on the developing human nervous system, researchers and clinicians rely on data collected from a number of model species that develop and mature at varying rates. We review the methods commonly used to extrapolate the timing of brain development from experimental mammalian species to humans, including morphological comparisons, "rules of thumb" and "event-based" analyses. Most are unavoidably limited in range or detail, many are necessarily restricted to rat/human comparisons, and few can identify brain regions that develop at different rates. We suggest this issue is best addressed using "neuroinformatics", an analysis that combines neuroscience, evolutionary science, statistical modeling and computer science. A current use of this approach relates numeric values assigned to 10 mammalian species and hundreds of empirically derived developing neural events, including specific evolutionary advances in primates. The result is an accessible, online resource (http://www.translatingtime.net/) that can be used to equate dates in the neurodevelopmental literature across laboratory species to humans, predict neurodevelopmental events for which data are lacking in humans, and help to develop clinically relevant experimental models. PMID:17368774

Clancy, Barbara; Finlay, Barbara L; Darlington, Richard B; Anand, K J S

2007-09-01

117

Accelerating Monte Carlo Molecular Simulations Using Novel Extrapolation Schemes Combined with Fast Database Generation on Massively Parallel Machines  

We introduce an efficient thermodynamically consistent technique to extrapolate and interpolate normalized Canonical NVT ensemble averages like pressure and energy for Lennard-Jones (L-J) fluids. Preliminary results show promising applicability in oil and gas modeling, where accurate determination of thermodynamic properties in reservoirs is challenging. The thermodynamic interpolation and thermodynamic extrapolation schemes predict ensemble averages at different thermodynamic conditions from expensively simulated data points. The methods reweight and reconstruct previously generated database values of Markov chains at neighboring temperature and density conditions. To investigate the efficiency of these methods, two databases corresponding to different combinations of normalized density and temperature are generated. One contains 175 Markov chains with 10,000,000 MC cycles each and the other contains 3000 Markov chains with 61,000,000 MC cycles each. For such massive database creation, two algorithms to parallelize the computations have been investigated. The accuracy of the thermodynamic extrapolation scheme is investigated with respect to classical interpolation and extrapolation. Finally, thermodynamic interpolation benefiting from four neighboring Markov chains points is implemented and compared with previous schemes. The thermodynamic interpolation scheme using knowledge from the four neighboring points proves to be more accurate than the thermodynamic extrapolation from the closest point only, while both thermodynamic extrapolation and thermodynamic interpolation are more accurate than the classical interpolation and extrapolation. The investigated extrapolation scheme has great potential in oil and gas reservoir modeling.That is, such a scheme has the potential to speed up the MCMC thermodynamic computation to be comparable with conventional Equation of State approaches in efficiency. In particular, this makes it applicable to large-scale optimization of L-J model parameters for hydrocarbons and other important reservoir species. The efficiency of the thermodynamic dependent techniques is expected to make the Markov chains simulation an attractive alternative in compositional multiphase flow simulation.

Amir, Sahar Z.

2013-05-01

118

Statistical atlas based extrapolation of CT data  

Science.gov (United States)

We present a framework to estimate the missing anatomical details from a partial CT scan with the help of statistical shape models. The motivating application is periacetabular osteotomy (PAO), a technique for treating developmental hip dysplasia, an abnormal condition of the hip socket that, if untreated, may lead to osteoarthritis. The common goals of PAO are to reduce pain, joint subluxation and improve contact pressure distribution by increasing the coverage of the femoral head by the hip socket. While current diagnosis and planning is based on radiological measurements, because of significant structural variations in dysplastic hips, a computer-assisted geometrical and biomechanical planning based on CT data is desirable to help the surgeon achieve optimal joint realignments. Most of the patients undergoing PAO are young females, hence it is usually desirable to minimize the radiation dose by scanning only the joint portion of the hip anatomy. These partial scans, however, do not provide enough information for biomechanical analysis due to missing iliac region. A statistical shape model of full pelvis anatomy is constructed from a database of CT scans. The partial volume is first aligned with the statistical atlas using an iterative affine registration, followed by a deformable registration step and the missing information is inferred from the atlas. The atlas inferences are further enhanced by the use of X-ray images of the patient, which are very common in an osteotomy procedure. The proposed method is validated with a leave-one-out analysis method. Osteotomy cuts are simulated and the effect of atlas predicted models on the actual procedure is evaluated.

Chintalapani, Gouthami; Murphy, Ryan; Armiger, Robert S.; Lepisto, Jyri; Otake, Yoshito; Sugano, Nobuhiko; Taylor, Russell H.; Armand, Mehran

2010-02-01

119

Data-based scale-extrapolation: estimating regional water resources using data from small river basins  

Science.gov (United States)

Estimation of world water resources under a changing climate is a key scientific issue for many environmental research areas with profound socio-economic significance. A new data-based scale-extrapolation method (Gong 2012) is proposed to estimate continental and regional water resources. The new method builds upon the assumption (Gong 2012) that, the dynamic interaction between climate and hydrology of a large river basin can be equally well resembled by multiple small regions, each characterized by a number of small river basins, which are typically two-orders-of-magnitude smaller than the large basin. Those small river basins contain sufficient information, not only on climate and land surface, but also on hydrological characteristics of the large region. Therefore, those multiple small regions can provide an ensemble of water recourse estimations for the large basin. The new method makes it possible for regional water resource estimations to benefit from a multitude of readily available measurements from small river basins. The scale-extrapolation methods also made it possible to study the interaction between climate and hydrology, and the climate change impact in un-gauged or partially gauged large river basins from data alone. The method offers ensemble predictions that bracket the estimation uncertainty. Because the scale-extrapolation uses different data and method compared to the modelling approach, it provides a unique opportunity to be compared with modelling results. Gong L., 2012. Data-based discharge extrapolation: estimating annual discharge for a partially gauged large river basin from its small sub-basins. Hydrol. Earth Syst. Sci. Discuss., 9, 6829-6856, 2012. doi:10.5194/hessd-9-6829-2012.

Gong, Lebing

2013-04-01

120

Multiparameter extrapolation of biodistribution data between species  

International Nuclear Information System (INIS)

Values of an inaccessible biological parameter in man may be predicted from values measured in animals by correlating with a parameter accessible in both species, such as body weight, energy production, excretion rate, etc. Predicting toxic effects, from environmental chemicals, of therapeutic doses for drug administration and of radiation absorbed dose from medical and environmental radioactivity depends on the rationalization of relationships between concentration and time when scaling to humans from animal data. For example, the retention of 99mTc, injected intravenously as pertechnetate, reaches 10% in the mouse at about 1 d, but this level occurs in humans at about 7 d. Making a simultaneous transformation between two species for the concentration and time variables by using a method of least-squares fitting, we have derived a series of transformation factors for several species. When correlated with a biological parameter such as body weight, these factors can be used to yield predicted values that are in good agreement with measured values. This system may be used with any related variables, making it useful for predicting other types of biological data

 
 
 
 
121

L2-Error Estimates of the Extrapolated Crank-Nicolson Discontinuous Galerkin Approximations for Nonlinear Sobolev Equations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We analyze discontinuous Galerkin methods with penalty terms, namely, symmetric interior penalty Galerkin methods, to solve nonlinear Sobolev equations. We construct finite element spaces on which we develop fully discrete approximations using extrapolated Crank-Nicolson method. We adopt an appropriate elliptic-type projection, which leads to optimal ??(L2) error estimates of discontinuous Galerkin approximations in both spatial direction and temporal direction.

Hyun Young Lee; Mi Ray Ohm; Jun Yong Shin

2010-01-01

122

Properties of infrared extrapolations in a harmonic oscillator basis  

CERN Document Server

We continue our studies of infrared (ir) and ultraviolet (uv) regulators of no-core shell model calculations. We extend our results that an extrapolation in the ir cutoff with the uv cutoff above the intrinsic uv scale of the interaction is quite successful, not only for the eigenstates of the Hamiltonian but also for expectation values of operators considered long range. The latter results are obtained with Hamiltonians transformed by the similarity renormalization group (SRG) evolution. On the other hand, a suggested extrapolation in the uv cutoff when the ir cutoff is below the intrinsic ir scale is neither robust nor reliable.

Coon, Sidney A

2014-01-01

123

Extrapolation of Extreme Response for Wind Turbines based on FieldMeasurements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The characteristic loads on wind turbines during operation are among others dependent on the mean wind speed, the turbulence intensity and the type and settings of the control system. These parameters must be taken into account in the assessment of the characteristic load. The characteristic load is normally determined by statistical extrapolation of the simulated response during operation according to IEC 61400-1 2005. However, this method assumes that the individual 10 min. time series are ...

Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

2009-01-01

124

Reduction of the resonance error in numerical homogenisation II: correctors and extrapolation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper is the companion article of [Gloria, M3AS, 21 (2011), No. 3, pp 1601-1630]. One common drawback among numerical homogenization methods is the presence of the so-called resonance error, which roughly speaking is a function of the ratio $\\frac{\\varepsilon}{\\rho}$, where $\\rho$ is a typical macroscopic lengthscale and $\\varepsilon$ is the typical size of the heterogeneities. In the present work, we make a systematic use of regularization and extrapolation to reduce t...

Gloria, Antoine; Habibi, Zakaria

2014-01-01

125

Performance characteristics of an extrapolation chamber for beta radiation detection  

International Nuclear Information System (INIS)

The performance of an extrapolation chamber was evaluated in ? radiation fields. The main characteristics such as calibration factors, energy and angular dependence, transmission factors in tissue and source-detector distance dependence have been determined. The influence of the collecting electrode area on the calibration factors was also investigated. (author)

126

Extrapolation of ZPR sodium void measurements to the power reactor  

International Nuclear Information System (INIS)

Sodium-voiding measurements of ZPPR assemblies 2 and 5 are analyzed with ENDF/B Version IV data. Computations include directional diffusion coefficients to account for streaming effects resulting from the plate structure of the critical assembly. Bias factors for extrapolating critical assembly data to the CRBR design are derived from the results of this analysis

127

Freeze-out parameters from continuum extrapolated lattice data  

CERN Document Server

We present continuum extrapolated lattice results for the higher order fluctuations of conserved charges in high temperature Quantum Chromodynamics. Through the matching of the grand canonical ensemble on the lattice to the net charge and net baryon distribution realized in heavy ion experiments the temperature and the chemical potential may be estimated at the time of chemical freeze-out

Borsanyi, S; Katz, S D; Krieg, S; Ratti, C; Szabo, K K

2013-01-01

128

Continuum extrapolation of energies of a four-quark system in lattice gauge theory  

CERN Document Server

A continuum extrapolation of static two- and four-quark energies calculated in quenched SU(2) lattice Monte Carlo is carried out based on Sommer's method of setting the scale. The beta-function is obtained as a side product of the extrapolations. Four-quark binding energies are found to be essentially constant at beta >= 2.35 unlike the two-body potentials. A model for four-quark energies, with explicit gluonic degrees of freedom removed, is fitted to these energies and the behaviour of the parameters of the model is investigated. An extension of the model using the first excited states of the two-body gluon field as additional basis states is found to be necessary for quarks at the corners of regular tetrahedra.

Pennanen, P

1997-01-01

129

Comparing Gravitational Waveform Extrapolation to Cauchy-Characteristic Extraction in Binary Black Hole Simulations  

CERN Document Server

We extract gravitational waveforms from numerical simulations of black hole binaries computed using the Spectral Einstein Code. We compare two extraction methods: direct construction of the Newman-Penrose (NP) scalar $\\Psi_4$ at a finite distance from the source and Cauchy-characteristic extraction (CCE). The direct NP approach is simpler than CCE, but NP waveforms can be contaminated by near-zone effects---unless the waves are extracted at several distances from the source and extrapolated to infinity. Even then, the resulting waveforms can in principle be contaminated by gauge effects. In contrast, CCE directly provides, by construction, gauge-invariant waveforms at future null infinity. We verify the gauge invariance of CCE by running the same physical simulation using two different gauge conditions. We find that these two gauge conditions produce the same CCE waveforms but show differences in extrapolated-$\\Psi_4$ waveforms. We examine data from several different binary configurations and measure the domi...

Taylor, Nicholas W; Reisswig, Christian; Scheel, Mark A; Chu, Tony; Kidder, Lawrence E; Szilagyi, Bela

2013-01-01

130

Improving the reliability of the background extrapolation in transmission electron microscopy elemental maps by using three pre-edge windows  

International Nuclear Information System (INIS)

Over the last decades, elemental maps have become a powerful tool for the analysis of the spatial distribution of the elements within specimen. In energy-filtered transmission electron microscopy (EFTEM) one commonly uses two pre-edge and one post-edge image for the calculation of elemental maps. However, this so called three-window method can introduce serious errors into the extrapolated background for the post-edge window. Since this method uses only two pre-edge windows as data points to calculate a background model that depends on two fit parameters, the quality of the extrapolation can be estimated only statistically assuming that the background model is correct. In this paper, we will discuss a possibility to improve the accuracy and reliability of the background extrapolation by using a third pre-edge window. Since with three data points the extrapolation becomes over-determined, this change permits us to estimate not only the statistical uncertainly of the fit, but also the systematic error by using the experimental data. Furthermore we will discuss in this paper the acquisition parameters that should be used for the energy windows to reach an optimal signal-to-noise ratio (SNR) in the elemental maps. -- Highlights: ? Comparison of three pre-edge windows to the regular two pre-edge windows. ? Investigation of the optimal positioning of the third pre-edge window. ? Description of the ?2 test for extrapolation quality check.

131

Application of the Weibull extrapolation to 137Cs geochronology in Tokyo Bay and Ise Bay, Japan  

International Nuclear Information System (INIS)

Considerable doubt surrounds the nature of processes by which 137Cs is deposited in marine sediments, leading to a situation where 137Cs geochronology cannot be always applied suitably. Based on extrapolation with Weibull distribution, the maximum concentration of 137Cs derived from asymptotic values for cumulative specific inventory was used to re-establish 137Cs geochronology, instead of original 137Cs profiles. Corresponding dating results for cores in Tokyo Bay and Ise Bay, Japan, by means of this new method, are in much closer agreement with those calculated from 210Pb method than the previous method

132

The 3D structure of an active region filament as extrapolated from photospheric and chromospheric observations  

CERN Document Server

The 3D structure of an active region (AR) filament is studied using nonlinear force-free field (NLFFF) extrapolations based on simultaneous observations at a photospheric and a chromospheric height. To that end, we used the Si I 10827 \\AA\\ line and the He I 10830 \\AA\\ triplet obtained with the Tenerife Infrared Polarimeter (TIP) at the VTT (Tenerife). The two extrapolations have been carried out independently from each other and their respective spatial domains overlap in a considerable height range. This opens up new possibilities for diagnostics in addition to the usual ones obtained through a single extrapolation from, typically, a photospheric layer. Among those possibilities, this method allows the determination of an average formation height of the He I 10830 \\AA\\ signal of \\approx 2 Mm above the surface of the sun. It allows, as well, to cross-check the obtained 3D magnetic structures in view of verifying a possible deviation from the force- free condition especially at the photosphere. The extrapolati...

Chaouche, L Yelles; Pillet, V Martínez; Moreno-Insertis, F

2012-01-01

133

A Application of Pole Extrapolation to the Mass Three Helium Isotope.  

Science.gov (United States)

We attempt to extract the value of the asymptotic D- to S-wave normalization parameter, (rho)(,D), of the ('3)He wave function, from precise measurements of the ('3)He(d,d) differential cross section, (sigma)((theta)), and tensor analyzing power, T(,22)((theta)). The pole extrapolation method used is analogous to the one applied to d-p elastic scattering measurements by Amado et al.('1) and by Conzett et al.('2). These works have yielded values of the deuteron asymptotic D- and S-wave parameter, (rho)(,D), which are in excellent agreement with the determinations made with sub-Coulomb (d,p) stripping reactions on heavy nuclei('3). The present work is both a natural and direct extension of these methods to the mass three system. The pole extrapolation technique relies on an extrapolation of measured scattering observables to non-physical values of cos((theta)(,cm)). For this purpose, precise angular distributions are needed. We have measured the cross section at 29 scattering angles (from (theta)(,cm) = 33.2(DEGREES) to 160.0(DEGREES)) to 2%, and the three tensor analyzing powers at 30 angles (from (theta)(,cm) = 29.1(DEGREES) to 160.0(DEGREES)) to (+OR-)0.001 for a deuteron bombarding energy of 10 MeV. Extrapolations of this data using the prescription of ref. 1 show very poor convergence and are not suitable for a determination of (rho)(,D) for the ('3)He nucleus. Furthermore, the conformal mapping method of Cutkosky and Deo('4) is found to slow the convergence of the. extrapolation function rather than accelerating it. This behavior is opposite that obtained with d-p elastic scattering. ('1)R. D. Amado, et al., Phys. Lett. 79B (1978) 368. ('2)H. E. Conzett, et al., Phys. Rev. Lett. 43 (1979) 572. ('3)K. Stephenson and W. Haeberli, Phys. Rev. Lett. 45 (1980) 520. ('4)R. E. Cutkosky and B. B. Deo, Phys. Rev. 174 (1968) 821.

Colby, Paul Campbell

134

Low-energy particle physics and chiral extrapolations  

CERN Document Server

In this review I discuss the role of chiral extrapolations for the determination of several phenomenologically relevant quantities, including light quark masses, meson decay constants and the axial charge of the nucleon. In particular, I investigate whether chiral extrapolations are sufficiently controlled in order to rightfully claim the accuracy which is quoted in recent compilations of these quantities. While this is the case for the masses of the light quarks and the ratio fK/fpi of decay constants, small inconsistencies in the chiral and continuum behaviour of individual decay constants fK and fpi, as well as the hadronic radii r0, r1 remain and must be clarified. In the case of the nucleon axial charge, gA, the chiral behaviour is still poorly understood due to the presence of other systematic effects.

Wittig, Hartmut

2012-01-01

135

An efficient extrapolation to the (T)/CBS limit  

Energy Technology Data Exchange (ETDEWEB)

We extrapolate to the perturbative triples (T)/complete basis set (CBS) limit using double ? basis sets without polarization functions (Wesleyan-1-Triples-2? or “Wes1T-2Z”) and triple ? basis sets with a single level of polarization functions (Wesleyan-1-Triples-3? or “Wes1T-3Z”). These basis sets were optimized for 102 species representing the first two rows of the Periodic Table. The species include the entire set of neutral atoms, positive and negative atomic ions, as well as several homonuclear diatomic molecules, hydrides, rare gas dimers, polar molecules, such as oxides and fluorides, and a few transition states. The extrapolated Wes1T-(2,3)Z triples energies agree with (T)/CBS benchmarks to within ±0.65 mE{sub h}, while the rms deviations of comparable model chemistries W1, CBS-APNO, and CBS-QB3 for the same test set are ±0.23 mE{sub h}, ±2.37 mE{sub h}, and ±5.80 mE{sub h}, respectively. The Wes1T-(2,3)Z triples calculation time for the largest hydrocarbon in the G2/97 test set, C{sub 6}H{sub 5}Me{sup +}, is reduced by a factor of 25 when compared to W1. The cost-effectiveness of the Wes1T-(2,3)Z extrapolation validates the usefulness of the Wes1T-2Z and Wes1T-3Z basis sets which are now available for a more efficient extrapolation of the (T) component of any composite model chemistry.

Ranasinghe, Duminda S. [Hall-Atwater Laboratories of Chemistry, Wesleyan University, Middletown, Connecticut 06459-0180 (United States); Barnes, Ericka C., E-mail: barnese8@southernct.edu [Department of Chemistry, Southern Connecticut State University, 501 Crescent Street, New Haven, Connecticut 06515-1355 (United States)

2014-05-14

136

An efficient extrapolation to the (T)/CBS limit  

Science.gov (United States)

We extrapolate to the perturbative triples (T)/complete basis set (CBS) limit using double ? basis sets without polarization functions (Wesleyan-1-Triples-2? or "Wes1T-2Z") and triple ? basis sets with a single level of polarization functions (Wesleyan-1-Triples-3? or "Wes1T-3Z"). These basis sets were optimized for 102 species representing the first two rows of the Periodic Table. The species include the entire set of neutral atoms, positive and negative atomic ions, as well as several homonuclear diatomic molecules, hydrides, rare gas dimers, polar molecules, such as oxides and fluorides, and a few transition states. The extrapolated Wes1T-(2,3)Z triples energies agree with (T)/CBS benchmarks to within ±0.65 mEh, while the rms deviations of comparable model chemistries W1, CBS-APNO, and CBS-QB3 for the same test set are ±0.23 mEh, ±2.37 mEh, and ±5.80 mEh, respectively. The Wes1T-(2,3)Z triples calculation time for the largest hydrocarbon in the G2/97 test set, C6H5Me+, is reduced by a factor of 25 when compared to W1. The cost-effectiveness of the Wes1T-(2,3)Z extrapolation validates the usefulness of the Wes1T-2Z and Wes1T-3Z basis sets which are now available for a more efficient extrapolation of the (T) component of any composite model chemistry.

Ranasinghe, Duminda S.; Barnes, Ericka C.

2014-05-01

137

Properties of a commercial extrapolation chamber in ? radiation fields  

International Nuclear Information System (INIS)

A commercial extrapolation chamber was tested in different ? radiation fields and its properties investigated. Its usefulness for ? radiation calibration and dosimetry was verified. Experiments were performed in order to obtain the main characteristics such as the calibration factors (and consequently the energy dependence) for all chamber collecting electrodes (between 10 and 40 mm diameter), the transmission factors in tissue and the useful source-detector distance range

138

An efficient extrapolation to the (T)/CBS limit  

International Nuclear Information System (INIS)

We extrapolate to the perturbative triples (T)/complete basis set (CBS) limit using double ? basis sets without polarization functions (Wesleyan-1-Triples-2? or “Wes1T-2Z”) and triple ? basis sets with a single level of polarization functions (Wesleyan-1-Triples-3? or “Wes1T-3Z”). These basis sets were optimized for 102 species representing the first two rows of the Periodic Table. The species include the entire set of neutral atoms, positive and negative atomic ions, as well as several homonuclear diatomic molecules, hydrides, rare gas dimers, polar molecules, such as oxides and fluorides, and a few transition states. The extrapolated Wes1T-(2,3)Z triples energies agree with (T)/CBS benchmarks to within ±0.65 mEh, while the rms deviations of comparable model chemistries W1, CBS-APNO, and CBS-QB3 for the same test set are ±0.23 mEh, ±2.37 mEh, and ±5.80 mEh, respectively. The Wes1T-(2,3)Z triples calculation time for the largest hydrocarbon in the G2/97 test set, C6H5Me+, is reduced by a factor of 25 when compared to W1. The cost-effectiveness of the Wes1T-(2,3)Z extrapolation validates the usefulness of the Wes1T-2Z and Wes1T-3Z basis sets which are now available for a more efficient extrapolation of the (T) component of any composite model chemistry

139

An efficient extrapolation to the (T)/CBS limit.  

Science.gov (United States)

We extrapolate to the perturbative triples (T)/complete basis set (CBS) limit using double ? basis sets without polarization functions (Wesleyan-1-Triples-2? or "Wes1T-2Z") and triple ? basis sets with a single level of polarization functions (Wesleyan-1-Triples-3? or "Wes1T-3Z"). These basis sets were optimized for 102 species representing the first two rows of the Periodic Table. The species include the entire set of neutral atoms, positive and negative atomic ions, as well as several homonuclear diatomic molecules, hydrides, rare gas dimers, polar molecules, such as oxides and fluorides, and a few transition states. The extrapolated Wes1T-(2,3)Z triples energies agree with (T)/CBS benchmarks to within ±0.65 mEh, while the rms deviations of comparable model chemistries W1, CBS-APNO, and CBS-QB3 for the same test set are ±0.23 mEh, ±2.37 mEh, and ±5.80 mEh, respectively. The Wes1T-(2,3)Z triples calculation time for the largest hydrocarbon in the G2/97 test set, C6H5Me(+), is reduced by a factor of 25 when compared to W1. The cost-effectiveness of the Wes1T-(2,3)Z extrapolation validates the usefulness of the Wes1T-2Z and Wes1T-3Z basis sets which are now available for a more efficient extrapolation of the (T) component of any composite model chemistry. PMID:24832262

Ranasinghe, Duminda S; Barnes, Ericka C

2014-05-14

140

Improved Richardson's extrapolation spreadsheet calculator for numerical differentiation  

Science.gov (United States)

In this paper, we have improved the limitations of our previous Richardson's extrapolation spreadsheet calculator for computing differentiations numerically. These limitations are the value of D(0,0) keyed in by users using 3-point central difference formula, and the fact that the previous spreadsheet calculator can only calculate the approximate definite differentiation up to level 4 × 4. If the function to be differentiated is complicated, calculating D(0,0) using 3-point central difference formula can be tedious as parentheses should be put in a proper order when writing the calculation command. Otherwise, the calculation command may lead to a wrong answer. In this improved Richardson's extrapolation spreadsheet calculator, we redesigned the Richardson's extrapolation spreadsheet calculator, where users are only required to give the value of x, the function to be differentiated f(x), and the step size h value without writing the command to obtain D(0,0). Consequently, the calculations will be done automatically to approximate the definite differentiation up to level 10 × 10.

Tay, Kim Gaik; Kek, Sie Long; Abdul-Kahar, Rosmila

2014-07-01

 
 
 
 
141

Further improvement of temporal resolution of seismic data by autoregressive (AR) spectral extrapolation  

Science.gov (United States)

Seismic data have still no enough temporal resolution because of band-limited nature of available data even if it is deconvolved. However, lower and higher frequency information belonging to seismic data is missing and it is not directly recovered from seismic data. In this paper, a method originally applied by Honarvar et al. [Honarvar, F., Sheikhzadeh, H., Moles, M., Sinclair, A.N., 2004. Improving the time-resolution and signal-noise ratio of ultrasonic NDE signals. Ultrasonics 41, 755-763.] which is the combination of the most widely used Wiener deconvolution and AR spectral extrapolation in frequency domain is briefly reviewed and is applied to seismic data to improve temporal resolution further. The missing frequency information is optimally recovered by forward and backward extrapolation based on the selection of a high signal-noise ratio (SNR) of signal spectrum deconvolved in signal processing technique. The combination of the two methods is firstly tested on a variety of synthetic examples and then applied to a stacked real trace. The selection of necessary parameters in Wiener filtering and in extrapolation are discussed in detail. It is used an optimum frequency windows between 3 and 10 dB drops by comparing results from these drops, while frequency windows are used as standard between 2.8 and 3.2 dB drops in study of Honarvar et al. [Honarvar, F., Sheikhzadeh, H., Moles, M., Sinclair, A.N., 2004. Improving the time-resolution and signal-noise ratio of ultrasonic NDE signals. Ultrasonics 41, 755-763.]. The results obtained show that the application of the purposed signal processing technique considerably improves temporal resolution of seismic data when compared with the original seismic data. Furthermore, AR based spectral extrapolated data can be almost considered as reflectivity sequence of layered medium. Consequently, the combination of Wiener deconvolution and AR spectral extrapolation can reveal some details of seismic data that cannot be observed in raw signal or which lost during the previous processing.

Karsl?, Hakan

2006-08-01

142

High-level waste package licensing considerations for extrapolating test data  

International Nuclear Information System (INIS)

Programs intended to provide supporting information for the high-level radioactive waste (HLW) repository program must consider the licensing requirements and the technical issues involved with extrapolation of short-term test data to periods of up to 10,000 years. The licensing requirements of the Nuclear Regulatory Commission (NRC), and the issues the NRC staff considers important for the development of predictive methods, are described. Because performance predictions of the geologic repository and particular components of the waste package must largely be based upon inference, a reasonable assurance, on the basis of the record before the Commission, is the general standard that will be required. 3 references, 2 figures

143

Mass extrapolation of quarks and leptons to higher generations  

International Nuclear Information System (INIS)

An empirical mass formula is tested for the basic fermion sequences of charged quarks and leptons. This relation is a generalization of Barut's mass formula for the lepton sequence (e, ?, tau ....). It is found that successful mass extrapolation to the third and possibly to other higher generations (N > 2) can be obtained with the first and second generation masses as inputs, which predicts the top quark mass msub(t) to be around 20 GeV. This also leads to the mass ratios between members of two different sequences (i) and (i') corresponding to the same higher generations (N > 2). (author)

144

Properties of a commercial extrapolation chamber in beta radiation fields  

International Nuclear Information System (INIS)

A commercial extrapolation chamber (PTW, Germany) was tested in different beta radiation fields and its properties investigated. Its usefulness for beta radiation calibration and dosimetry was demonstrated. The Beta Secondary Standard setup of the IPEN calibration laboratory was utilized. This system, developed by the Physikalisch-Tecknische Bundesanstalt, Brunswick (Germany) and manufactured by Buchler and Co., consists of a source stand, a control unit with timer and four interchangeable beta sources: 90Sr-90Y (1850 and 74 MBq), 204Tl (18,5 MBq) ionization current detection. The variable volume ionization chamber of cylindrical form is provided with different collecting electrodes of tissue equivalent material and Mylar entrance windows of different thickesses

145

3D-Euler calculations using characteristic flux extrapolation  

Science.gov (United States)

The characteristic-upwinding flux-extrapolation scheme developed by Eberle (1983 and 1984) for the numerical computation of solutions to the Euler equations is briefly characterized, and sample results are presented graphically. The technique requires no added artificial viscosity and only one grid sweep per iteration for the steady-state computation. The examples shown include the flow past an automobile, an ONERA M6 wing, a Dillner wing, an aircraft, and a Butler wing and demonstrate the promise of the technique in computations for low and high freestream Mach numbers, vortex flows, and unsteady flows.

Eberle, A.

1985-01-01

146

National pattern for the realization of the unit of the dose speed absorbed in air for beta radiation. (Method: Ionometer, cavity of Bragg-Gray implemented in an extrapolation chamber with electrodes of variable separation, exposed to a field of beta radiation of {sup 90}Sr/{sup 90}Y); Patron Nacional para la realizacion de la unidad de la rapidez de dosis absorbida en aire para radiacion beta. (Metodo: Ionometrico, cavidad de Bragg-Gray implementada en una camara de extrapolacion con electrodos de separacion variable, expuesta a un campo de radiacion beta de {sup 90}Sr/{sup 90}Y)  

Energy Technology Data Exchange (ETDEWEB)

From the year of 1987 the Department of Metrology of the ININ, in their Secondary Laboratory of Calibration Dosimetric, has a patron group of sources of radiation beta and an extrapolation chamber of electrodes of variable separation.Their objective is to carry out of the unit of the dose speed absorbed in air for radiation beta. It uses the ionometric method, cavity Bragg-Gray in the extrapolation chamber with which it counts. The services that offers are: i) it Calibration : Radioactive Fuentes of radiation beta, isotopes: {sup 90}Sr/{sup 90}Y; Ophthalmic applicators {sup 9}0{sup S}r/{sup 90}Y; Instruments for detection of beta radiation with to the radiological protection: Ionization chambers, Geiger-Muller, etc.; Personal Dosemeters. ii) Irradiation with beta radiation of materials to the investigation. (Author)

Alvarez R, M. T.; Morales P, J. R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2001-01-15

147

Visualization and Nowcasting for Aviation using online verified ensemble weather radar extrapolation.  

Science.gov (United States)

Nowcasting of precipitation events, especially thunderstorm events or winter storms, has high impact on flight safety and efficiency for air traffic management. Future strategic planning by air traffic control will result in circumnavigation of potential hazardous areas, reduction of load around efficiency hot spots by offering alternatives, increase of handling capacity, anticipation of avoidance manoeuvres and increase of awareness before dangerous areas are entered by aircraft. To facilitate this rapid update forecasts of location, intensity, size, movement and development of local storms are necessary. Weather radar data deliver precipitation analysis of high temporal and spatial resolution close to real time by using clever scanning strategies. These data are the basis to generate rapid update forecasts in a time frame up to 2 hours and more for applications in aviation meteorological service provision, such as optimizing safety and economic impact in the context of sub-scale phenomena. On the basis of tracking radar echoes by correlation the movement vectors of successive weather radar images are calculated. For every new successive radar image a set of ensemble precipitation fields is collected by using different parameter sets like pattern match size, different time steps, filter methods and an implementation of history of tracking vectors and plausibility checks. This method considers the uncertainty in rain field displacement and different scales in time and space. By validating manually a set of case studies, the best verification method and skill score is defined and implemented into an online-verification scheme which calculates the optimized forecasts for different time steps and different areas by using different extrapolation ensemble members. To get information about the quality and reliability of the extrapolation process additional information of data quality (e.g. shielding in Alpine areas) is extrapolated and combined with an extrapolation-quality-index. Subsequently the probability and quality information of the forecast ensemble is available and flexible blending to numerical prediction model for each subarea is possible. Simultaneously with automatic processing the ensemble nowcasting product is visualized in a new innovative way which combines the intensity, probability and quality information for different subareas in one forecast image.

Kaltenboeck, Rudolf; Kerschbaum, Markus; Hennermann, Karin; Mayer, Stefan

2013-04-01

148

Classification of future 5 MW turbines by extrapolation of current trends  

Energy Technology Data Exchange (ETDEWEB)

This report is part of the STABTOOL project. The goals of the STABTOOL project can be summarised as follows: (1) first establish the elastic configuration of the present megawatt scaled wind turbines, and making an inventory of the present design trends and trends for future wind turbine developments w.r.t changes in the elastic configuration; (2) to make an inventory of the different types of instabilities which can occur for the present and next generation wind turbines for both onshore and offshore applications; (3) to make an inventory of analysis and design methods and development or adjustment of calculation methods. The final objective of the STABTOOL project is to create STABility TOOLs: a simple set of calculation models and methods for specific forms of aeroelastic instabilities and vibration problems which are applicable for both present and future large wind turbines. This report concerns the up scaling of the selected elastic configurations described in ST-NW-1-004: 2-blade, (active)pitch controlled, fixed speed (Kvaerner WTS 80M); 3-blade, (active)stall controlled, fixed speed (Nedwind 62 ); 3-blade, pitch controlled variable speed (Lagerwey 50/1000). Based on scaling rules and extrapolation of trend figures, the characteristics of the future 5MW class of wind turbines is estimated. The Nedwind based extrapolation is considered to be an onshore turbine, whereas the others are offshore. 5 refs.

Thakoer, R.; Van Kuik, G.A.M.; Van Leeuwen, H.L.

1999-09-01

149

Why does the Aitken extrapolation often help to attain convergence in self-consistent field calculations?  

International Nuclear Information System (INIS)

The Aitken (three-point) extrapolation is one of the most popular convergence accelerators in the SCF calculations. The conditions that guarantee the Aitken extrapolation to bring about an unconditional convergence in the SCF process are examined. Classification of the SCF divergences is presented and it is shown that the extrapolation can be expected to work properly only in the case of oscillatory divergence

150

Muon and neutrino spectra - Extrapolation from muon spectrometer measurements  

International Nuclear Information System (INIS)

A most probable sea level muon spectrum is derived and used to extrapolate deep underwater muon rates, neutrino spectra and the direct production of neutrinos. The vertical spectra up to 1 TeV obtained by the Kiel group (1979) are compared with those obtained from MUTRON (1979) up to 10 TeV at an angle of 88 deg, and an analytic expression for muon intensity beyond 10 TeV is extrapolated with a spectral index of 2.8. Assuming this muon spectrum, various underwater muon rates are calculated as a function of local zenith angle for a depth of 5 km. The neutrino flux is estimated from the combined positive and negative muon fluxes, noting major uncertainties due to poor knowledge of the positive kaon/positive pion and positive kaon/negative kaon production ratios, and is found to agree well in the 1 TeV range with previous results (Volkova, 1979). Differential electron and muon neutrino fluxes are also estimated for two values of the kaon/pion ratio. The sensitivity of angular neutrino distribution to rates of direct production is considered, and it is concluded that several hundred events above 100 TeV would be required to detect direct production as a change in angular distribution from a function of the secant of the zenith angle to isotropic

151

2D interpolation and extrapolation of discrete magnetic measurements with toroidal harmonics for equilibrium reconstruction in a tokamak  

Science.gov (United States)

We present a method based on the use of toroidal harmonics and on a modelization of the poloidal field coils and divertor coils for the 2D interpolation and extrapolation of discrete magnetic measurements in a tokamak. The method is generic and can be used to provide the Cauchy boundary conditions needed as input by a fixed domain equilibrium reconstruction code like Equinox (Blum et al 2012 J. Comput. Phys. 231 960–80). It can also be used to extrapolate the magnetic measurements in order to compute the plasma boundary itself. The proposed method and algorithm are detailed in this paper and results from numerous numerical experiments are presented. The method is foreseen to be used in the real-time plasma control loop on the WEST tokamak (Bucalossi et al 2011 Fusion Eng. Des. 86 684–8).

Faugeras, Blaise; Blum, Jacques; Boulbe, Cedric; Moreau, Philippe; Nardon, Eric

2014-11-01

152

CORONAL ALFVEN SPEED DETERMINATION: CONSISTENCY BETWEEN SEISMOLOGY USING AIA/SDO TRANSVERSE LOOP OSCILLATIONS AND MAGNETIC EXTRAPOLATION  

Energy Technology Data Exchange (ETDEWEB)

Two transversely oscillating coronal loops are investigated in detail during a flare on the 2011 September 6 using data from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. We compare two independent methods to determine the Alfven speed inside these loops. Through the period of oscillation and loop length, information about the Alfven speed inside each loop is deduced seismologically. This is compared with the Alfven speed profiles deduced from magnetic extrapolation and spectral methods using AIA bandpass. We find that for both loops the two methods are consistent. Also, we find that the average Alfven speed based on loop travel time is not necessarily a good measure to compare with the seismological result, which explains earlier reported discrepancies. Instead, the effect of density and magnetic stratification on the wave mode has to be taken into account. We discuss the implications of combining seismological, extrapolation, and spectral methods in deducing the physical properties of coronal loops.

Verwichte, E.; Foullon, C.; White, R. S. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Van Doorsselaere, T., E-mail: Erwin.Verwichte@warwick.ac.uk [Centre for Plasma Astrophysics, Department of Mathematics, Katholieke Universiteit Leuven, Celestijnenlaan 200B, B-3001 Leuven (Belgium)

2013-04-10

153

Application of extrapolation chambers in low-energy X-rays as reference systems.  

Science.gov (United States)

Extrapolation chambers are instruments designed to measure doses of low-energy radiations, mainly beta radiation. In this work, a commercial extrapolation chamber and a homemade extrapolation chamber were applied in measurements using standard radiotherapy X-ray beams. Saturation curves and polarity effect as well as short- and medium-term stabilities were obtained, and these results are within the recommendations of the International Electrotechnical Commission (IEC). The response linearity and the extrapolation curves were also obtained, and they presented good behavior. The results show the usefulness of these extrapolation chambers in low-energy X-ray beams. PMID:22520689

da Silva, Eric A B; Caldas, Linda V E

2012-07-01

154

Extrapolation from animals to the human for the retention of radiothallium in the blood  

International Nuclear Information System (INIS)

The extrapolation of tissue distribution data from animal to human has implications in the clinical application of new radiopharmaceuticals, in studies of biodistribution and biokinetics, and in estimation of radiation absorbed dose. The extrapolative method described in this study is based on the assumption that the mechanism of tissue distribution of a radionuclide in different mammalian species is similar. This assumption implies that the fractional distribution function, ?/sub h/(t), of a radionuclide in a specific tissue of one species is related to the corresponding fractional distribution function in any other species by linear transformations in the activity and time variables. Hence, the successful application of the extrapolative technique requires determining a reference ?/sub h/(t) based on a conveniently studied species and finding the relationships between the factors of the transformations and one or more measurable species-dependent parameters. To test this approach, data for retention of T1-201 in the blood of several species were used. Detailed biokinetic data in mice, collected in our laboratory, were used to determine the reference ?/sub h/(t) mouse. Data for other species were extracted from the literature and compared with ?/sub h/(t) mouse to determine the transformation factors, using the least squares fitting technique. These factors appear, on the basis of the data available, to be power functions of body weight. Retention of activity in body weight. Retention of activity in blood was chosen as a test of the theory because data have been published for several nonhuman species as well as verifying values for the human

155

Image reconstruction: a unifying model for resolution enhancement and data extrapolation. Tutorial.  

Science.gov (United States)

In reconstructing an object function F(r) from finitely many noisy linear-functional values integral of F(r)Gn(r)dr we face the problem that finite data, noisy or not, are insufficient to specify F(r) uniquely. Estimates based on the finite data may succeed in recovering broad features of F(r), but may fail to resolve important detail. Linear and nonlinear, model-based data extrapolation procedures can be used to improve resolution, but at the cost of sensitivity to noise. To estimate linear-functional values of F(r) that have not been measured from those that have been, we need to employ prior information about the object F(r), such as support information or, more generally, estimates of the overall profile of F(r). One way to do this is through minimum-weighted-norm (MWN) estimation, with the prior information used to determine the weights. The MWN approach extends the Gerchberg-Papoulis band-limited extrapolation method and is closely related to matched-filter linear detection, the approximation of the Wiener filter, and to iterative Shannon-entropy-maximization algorithms. Non-linear versions of the MWN method extend the noniterative, Burg, maximum-entropy spectral-estimation procedure. PMID:16477830

Shieh, Hsin M; Byrne, Charles L; Fiddy, Michael A

2006-02-01

156

Extrapolation of extreme response for different mooring line systems of floating wave energy converters  

DEFF Research Database (Denmark)

Mooring systems for floating wave energy converters (WECs) are a major cost driver. Failure of mooring systems often occurs due to extreme loads. This paper introduces an extrapolation method for extreme response which accounts for the control system of a WEC that controls the loads onto the structure and the harvested power of the device as well as the fact that extreme loads may occur during operation and not at extreme wave states when the device is in storm protection mode. The extrapolation method is based on shortterm load time series and applied to a case study where up-scaled surge load measurements from lab-scaled WEPTOS WEC are taken. Different catenary anchor leg mooring (CALM) systems as well as single anchor legmooring (SALM)mooring systemsare implemented for a dynamic simulation with different number of mooring lines. Extreme tension loads with a return period of 50 years are assessed for the hawser as well as at the different mooring lines. Furthermore, the extreme load impact given failure of one mooring line is assessed and compared with extreme loads given no system failure.

Ambühl, Simon; Sterndorff, Martin

2014-01-01

157

Image extrapolation for photo stitching using nonlocal patch-based inpainting  

Science.gov (United States)

Image alignment and mosaicing are usually performed on a set of overlapping images, using features in the area of overlap for seamless stitching. In many cases such images have different size and shape. So we need to crop panoramas or to use image extrapolation for them. This paper focuses on novel image inpainting method based on modified exemplar-based technique. The basic idea is to find an example (patch) from an image using local binary patterns, and replacing non-existed (`lost') data with it. We propose to use multiple criteria for a patch similarity search since often in practice existed exemplar-based methods produce unsatisfactory results. The criteria for searching the best matching uses several terms, including Euclidean metric for pixel brightness and Chi-squared histogram matching distance for local binary patterns. A combined use of textural geometric characteristics together with color information allows to get more informative description of the patches. In particular, we show how to apply this strategy for image extrapolation for photo stitching. Several examples considered in this paper show the effectiveness of the proposed approach on several test images.

Voronin, V. V.; Marchuk, V. I.; Sherstobitov, A. I.; Semenischev, E. A.; Agaian, S.; Egiazarian, K.

2014-05-01

158

UFOs in the LHC: Observations, studies and extrapolations  

CERN Document Server

Unidentified falling objects (UFOs) are potentially a major luminosity limitation for nominal LHC operation. They are presumably micrometer sized dust particles which lead to fast beam losses when they interact with the beam. With large-scale increases and optimizations of the beam loss monitor (BLM) thresholds, their impact on LHC availability was mitigated from mid 2011 onwards. For higher beam energy and lower magnet quench limits, the problem is expected to be considerably worse, though. In 2011/12, the diagnostics for UFO events were significantly improved: dedicated experiments and measurements in the LHC and in the laboratory were made and complemented by FLUKA simulations and theoretical studies. The state of knowledge, extrapolations for nominal LHC operation and mitigation strategies are presented

Baer, T; Cerutti, F; Ferrari, A; Garrel, N; Goddard, B; Holzer, EB; Jackson, S; Lechner, A; Mertens, V; Misiowiec, M; Nebot del Busto, E; Nordt, A; Uythoven, J; Vlachoudis, V; Wenninger, J; Zamantzas, C; Zimmermann, F; Fuster, N

2012-01-01

159

A new clinical scintillation camera with pulse tail extrapolation electronics  

International Nuclear Information System (INIS)

This paper reports the performance of a new scintillation camera, designed for high event rate capability, evaluated. The system consisted of a 400 mm field-of-view NaI(Tl) camera with 61 photomultiplier tubes and modified Starcam electronics. A significant feature of the system was circuitry for performing pulse tail extrapolation and separation of individual pulses involved in pulse pile-up events. System deadtime, flood field uniformity, energy resolution, linearity, spatial resolution bar phantom image quality and misplaced events were evaluated for count rates up to 200 kcps in a 20% photopeak window. The authors' results indicate that this camera design does not compromise image quality at normal clinical count rates and at higher event rates can provide better image quality and increased sensitivity over many Anger cameras currently employed in nuclear medicine

160

Sigma terms from an SU(3) chiral extrapolation  

Science.gov (United States)

We report a new analysis of lattice simulation results for octet baryon masses in 2+1-flavor QCD, with an emphasis on a precise determination of the pion-nucleon and strangeness nucleon sigma terms. A controlled chiral extrapolation of a recent PACS-CS Collaboration data set yields baryon masses which exhibit remarkable agreement both with experimental values at the physical point and with the results of independent lattice QCD simulations at unphysical meson masses. Using the Feynman-Hellmann relation, we evaluate sigma commutators for all octet baryons. The small statistical uncertainty and considerably smaller model dependence allows a significantly more precise determination of the pion-nucleon sigma commutator and the strangeness sigma term than hitherto possible, subject to an unresolved issue concerning the lattice scale setting.

Shanahan, P. E.; Thomas, A. W.; Young, R. D.

2013-04-01

 
 
 
 
161

Sigma terms from an SU(3) chiral extrapolation  

CERN Document Server

We report a new analysis of lattice simulation results for octet baryon masses in 2+1-flavor QCD, with an emphasis on a precise determination of the strangeness nucleon sigma term. A controlled chiral extrapolation of a recent PACS-CS Collaboration data set yields baryon masses which exhibit remarkable agreement both with experimental values at the physical point and with the results of independent lattice QCD simulations at unphysical meson masses. Using the Feynman-Hellmann relation, we evaluate sigma commutators for all octet baryons. The small statistical uncertainty, and considerably smaller model-dependence, allows a signifcantly more precise determination of the pion-nucleon sigma commutator and the strangeness sigma term than hitherto possible, namely {\\sigma}{\\pi}N=45 \\pm 6 MeV and {\\sigma}s = 21 \\pm 6 MeV at the physical point.

Shanahan, P E; Young, R D

2012-01-01

162

Extrapolation from animals to the human for the retention of radiothallium in the blood  

International Nuclear Information System (INIS)

The extrapolation of tissue distribution data from animal to human has implications in the clinical application of new radiopharmaceuticals, in studies of biodistribution and biokinetics, and in estimation of radiation absorbed dose. The extrapolative method described in this study is based on the assumption that the mechanism of tissue distribution of a radionuclide in different mammalian species is similar. This assumption implies that the fractional distribution function, ?/sub h/(t), of a radionuclide in a specific tissue of one species is related to the corresponding fractional distribution function in any other species by linear transformations in the activity and time variables. To test this approach, data for retention of T1-201 in the blood of several species were used. Detailed biokinetic data in mice, collected in our laboratory, were used to determine the reference ?/sub h/(t)/sub mouse/. Data for other species were extracted from the literature and compared with ?/sub h/(t)/sub mouse/ to determine the transformation factors, using the least squares fitting technique. These factors appear, on the basis of the data available, to be power functions of body weight. Retention of activity in blood was chosen as a test of the theory because data have been published for several nonhuman species as well as verifying values for the human

163

Extrapolating W-Associated Jet-Production Ratios at the LHC  

CERN Document Server

Electroweak vector-boson production, accompanied by multiple jets, is an important background to searches for physics beyond the Standard Model. A precise and quantitative understanding of this process is helpful in constraining deviations from known physics. We study four key ratios in $W + n$-jet production at the LHC. We compute the ratio of cross sections for $W + n$- to $W + (n-1)$-jet production as a function of the minimum jet transverse momentum. We also study the ratio differentially, as a function of the $W$-boson transverse momentum; as a function of the scalar sum of the jet transverse energy, $H_T^{\\rm jets}$; and as a function of certain jet transverse momenta. We show how to use such ratios to extrapolate differential cross sections to $W+6$-jet production at next-to-leading order, and we cross-check the method against a direct calculation at leading order. We predict the differential distribution in $H_T^{\\rm jets}$ for $W+6$ jets at next-to-leading order using such an extrapolation. We use th...

Bern, Z; Cordero, F Febres; Hoeche, S; Kosower, D A; Ita, H; Maitre, D

2014-01-01

164

THREE-DIMENSIONAL STRUCTURE OF MICROWAVE SOURCES FROM SOLAR ROTATION STEREOSCOPY VERSUS MAGNETIC EXTRAPOLATIONS  

International Nuclear Information System (INIS)

We use rotation stereoscopy to estimate the height of a steady-state solar feature relative to the photosphere, based on its apparent motion in the image plane recorded over several days of observation. The stereoscopy algorithm is adapted to work with either one- or two-dimensional data (i.e., from images or from observations that record the projected position of the source along an arbitrary axis). The accuracy of the algorithm is tested on simulated data, and then the algorithm is used to estimate the coronal radio source heights associated with the active region NOAA 10956, based on multifrequency imaging data over seven days from the Siberian Solar Radio Telescope near 5.7 GHz, the Nobeyama Radio Heliograph at 17 GHz, as well as one-dimensional scans at multiple frequencies spanning the 5.98-15.95 GHz frequency range from the RATAN-600 instrument. The gyroresonance emission mechanism, which is sensitive to the coronal magnetic field strength, is applied to convert the estimated radio source heights at various frequencies, h(f), to information about magnetic field versus height B(h), and the results are compared to a magnetic field extrapolation derived from photospheric magnetic field observations obtained by Hinode and Michelson Doppler Imager. We found that the gyroresonant emission comes from heights exceeding the location of the third gyrolayer irrespective of the magnetic extrapolation method; implications of this finding for coronal magnetography and coronanding for coronal magnetography and coronal plasma physics are discussed.

165

Extrapolation procedures for calculating high-temperature gibbs free energies of aqueous electrolytes  

International Nuclear Information System (INIS)

Methods for calculating high-temprature Gibbs free energies of mononuclear cations and anions from room-temperature data are reviewed. Emphasis is given to species required for oxide solubility calculations relevant to mass transport situations in the nuclear industry. Free energies predicted by each method are compared to selected values calculated from recently reported solubility studies and other literature data. Values for monatomic ions estimated using the assumption anti C0p(T) = anti C0p(298) agree best with experiment to 423 K. From 423 K to 523 K, free energies from an electrostatic model for ion hydration are more accurate. Extrapolations for hydrolyzed species are limited by a lack of room-temperature entropy data and expressions for estimating these entropies are discussed. (orig.)

166

Extrapolation procedures for calculating high-temperature Gibbs free energies of aqueous electrolytes  

International Nuclear Information System (INIS)

Methods for calculating high-temperature Gibbs free energies of mononuclear cations and anions from room-temperature data are reviewed. Emphasis is given to species required for oxide solubility calculations relevant to mass transport situations in the nuclear industry. Free energies predicted by each method are compared with selected values calculated from recently reported solubility studies and other literature data. Values for monatomic ions estimated using the assumption anti Csub(p)0(T)=anti Csub(p)0(298) agree best with experiment to 423 K. From 423 to 523 K, free energies from an electrostatic model for ion hydration are more accurate. Extrapolations for hydrolysed species are limited by a lack of room-temperature entropy data and expressions for estimating these entropies are discussed. (author)

167

Entanglement entropy and negativity of disjoint intervals in CFT: Some numerical extrapolations  

CERN Document Server

The entanglement entropy and the logarithmic negativity can be computed in quantum field theory through a method based on the replica limit. Performing these analytic continuations in some cases is beyond our current knowledge, even for simple models. We employ a numerical method based on rational interpolations to extrapolate the entanglement entropy of two disjoint intervals for the conformal field theories given by the free compact boson and the Ising model. The case of three disjoint intervals is studied for the Ising model and the non compact free massless boson. For the latter model, the logarithmic negativity of two disjoint intervals has been also considered. Some of our findings have been checked against existing numerical results obtained from the corresponding lattice models.

De Nobili, Cristiano; Tonni, Erik

2015-01-01

168

The extrapolation of short term observation to time periods for isolation of long lived radioactive wastes (India)  

International Nuclear Information System (INIS)

The work presented covers different parts of a repository system such as near and far field aspects. Investigations are reported for the degradation of HLW glass, for the corrosion of container materials, for changes of geochemical environment in geological repositories, and for the thermo-mechanical behaviour of granitic host rock. Extrapolation methods are developed and applied for temperature and stress development in the host rock and for the radionuclide transport through a fractured system. (author)

169

Data-driven scale extrapolation: estimating yearly discharge for a large region by small sub-basins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Large-scale hydrological models and land surface models are so far the only tools for assessing current and future water resources. Those models estimate discharge with large uncertainties, due to the complex interaction between climate and hydrology, the limited availability and quality of data, as well as model uncertainties. A new purely data-driven scale-extrapolation method to estimate discharge for a large region solely from selected small sub-basins, which are typical...

Gong, L.

2014-01-01

170

Data-driven scale extrapolation : estimating yearly discharge for a large region by small sub-basins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Large-scale hydrological models and land surface models are so far the only tools for assessing current and future water resources. Those models estimate discharge with large uncertainties, due to the complex interaction between climate and hydrology, the limited availability and quality of data, as well as model uncertainties. A new purely data-driven scale-extrapolation method to estimate discharge for a large region solely from selected small sub-basins, which are typically 1-2 orders of m...

Gong, Lebing

2014-01-01

171

Epistemological considerations in the extrapolation of metabolic data from non-humans to humans  

International Nuclear Information System (INIS)

The rationale underlying interspecies extrapolation of metabolic data has been based primarily on pragmatic concerns. Little attention has been given to the extent to which such extrapolations have a firm epistemological basis. The strength of this approach for model-free (purely empirical) extrapolation and for extrapolation involving a variety of theoretical constructs is examined in this paper. An attempt is made to provide some understanding of the degree of confidence that can be placed in the extrapolation of metabolic data from one species to another. Published results for a wide variety of radionuclides are analyzed and the importance of these results to the field of nuclear medicine is explored. Problems inherent in the logic of extrapolation are then delineated in view of these historical data

172

Characterization and application of two extrapolation chambers in standard X radiation beams  

International Nuclear Information System (INIS)

The extrapolation chambers are ionization chambers with variable volume, and they are mainly utilized as beta radiation detectors. In this work two extrapolation chambers were characterized, a commercial PTW extrapolation chamber and another extrapolation chamber developed at the Calibration Laboratory of IPEN, for application as reference systems in mammography, conventional diagnostic radiology and radiotherapy beams. The results obtained from the characterization tests of the chamber response: leakage current, short- and medium terms stability, determination of the saturation currents and the ion collection efficiencies, angular and energy dependence, show that these extrapolation chambers may be utilized for low-energy X radiation beam dosimetry. The transmission factors in tissue and the calibration factors were also determined for all cited radiation qualities. Finally, a procedure was established for calibration of radiation detectors in standard X radiation beams, using the extrapolation chambers. (author)

173

Application of extrapolation chambers in low-energy X-rays as reference systems  

International Nuclear Information System (INIS)

Extrapolation chambers are instruments designed to measure doses of low-energy radiations, mainly beta radiation. In this work, a commercial extrapolation chamber and a homemade extrapolation chamber were applied in measurements using standard radiotherapy X-ray beams. Saturation curves and polarity effect as well as short- and medium-term stabilities were obtained, and these results are within the recommendations of the International Electrotechnical Commission (IEC). The response linearity and the extrapolation curves were also obtained, and they presented good behavior. The results show the usefulness of these extrapolation chambers in low-energy X-ray beams. - Highlights: ? Usefulness of two extrapolation chambers was studied for low-energy X-ray beam dosimetry. ? Performance of the chambers was verified at standard X-radiation qualities. ? Both chambers are suited for use with radiotherapy quality X-ray beams.

174

Surface extrapolation length and director structures in confined nematics  

CERN Document Server

We report the results of Monte Carlo simulations of the Lebwohl--Lasher model of nematic liquid crystals confined to cylindrical cavities with homeotropic anchoring. We show that the ratio of the bulk to surface couplings is not in general equal to the corresponding parameter K/W used in elastic theory (where K is the Frank elastic constant in the one constant approximation and W is the surface anchoring strength). By measuring the temperature dependence of K/W (which is equivalent to the surface extrapolation length) we are able to reconcile the results of our simulations as well as others with the predictions of elastic theory. We find that the rate at which we cool the system from the isotropic to nematic phase plays a crucial role in the development of the final director structure, because of a large free energy barrier separating different director structures as well as the temperature dependence of $K/W$. With a suitably fast cooling rate we are able to keep the system out of a metastable planar state a...

Priezjev, N V; Pelcovits, Robert A.

2000-01-01

175

Adaptation to implied tilt: extensive spatial extrapolation of orientation gradients  

Directory of Open Access Journals (Sweden)

Full Text Available To extract the global structure of an image, the visual system must integrate local orientation estimates across space. Progress is being made towards understanding this integration process, but very little is known about whether the presence of structure exerts a reciprocal influence on local orientation coding. We have previously shown that adaptation to patterns containing circular or radial structure induces tilt-aftereffects (TAEs, even in locations where the adapting pattern was occluded. These spatially ‘remote’ TAEs have novel tuning properties and behave in a manner consistent with adaptation to the local orientation implied by the circular structure (but not physically present at a given test location. Here, by manipulating the spatial distribution of local elements in noisy circular textures, we demonstrate that remote TAEs are driven by the extrapolation of orientation structure over remarkably large regions of visual space (more than 20 degrees. We further show that these effects are not specific to adapting stimuli with polar orientation structure (i.e. circular, radial, but require a gradient of orientation change across space. Our results suggest that mechanisms of visual adaptation exploit orientation gradients to predict the local pattern content of unfilled regions of space.

NeilRoach

2013-07-01

176

Measurement of fatty acid oxidation: validation of isotopic equilibrium extrapolation  

International Nuclear Information System (INIS)

Measurement of whole body substrate oxidation requires prolonged isotope infusion to attain plateau specific activity (SA) of expired CO2. We have investigated in 13 hospitalized patients a technique whereby plateau 14CO2 SA is extrapolated using computer curve fitting based upon the early exponential rise. A primed-constant infusion of albumin-bound 1-14C-palmitate was continued for 260 minutes with isotope priming of the secondary bicarbonate pool at 70 minutes. Plasma free fatty acid (FFA) SA reached steady state by 40 minutes and was 91% +/- 4% (SE) of values obtained at 190 to 260 minutes. At 70 minutes 14CO2 SA reached only 44% +/- 1% of the 190 to 260 minute values, which were consistently at plateau. The predicted steady state 14CO2 SA from the 40 to 70 minute curves and the FFA oxidation rates calculated from those values were 94% +/- 2% and 102% +/- 4%, respectively, of values measured at steady state (190 to 260 minutes). The relationship between predicted and measured values approximated the line of identity for 14CO2 SA (y = 0.90x + 0.14, r = .98, P less than .001) and FFA oxidation (y = 1.02x, r = .98, P less than .001). The results suggest that FFA oxidation can be accurately calculated using a short infusion of labeled FFA without bicarbonate pool priming, thus avoiding overpriming or underpriming and possibly allowing multiple studies and dimiossibly allowing multiple studies and diminished radioisotope exposure

177

Flash-lag effect: complicating motion extrapolation of the moving reference-stimulus paradoxically augments the effect.  

Science.gov (United States)

One fundamental property of the perceptual and cognitive systems is their capacity for prediction in the dynamic environment; the flash-lag effect has been considered as a particularly suggestive example of this capacity (Nijhawan in nature 370:256-257, 1994, Behav brain sci 31:179-239, 2008). Thus, because of involvement of the mechanisms of extrapolation and visual prediction, the moving object is perceived ahead of the simultaneously flashed static object objectively aligned with the moving one. In the present study we introduce a new method and report experimental results inconsistent with at least some versions of the prediction/extrapolation theory. We show that a stimulus moving in the opposite direction to the reference stimulus by approaching it before the flash does not diminish the flash-lag effect, but rather augments it. In addition, alternative theories (in)capable of explaining this paradoxical result are discussed. PMID:21818621

Bachmann, Talis; Murd, Carolina; Põder, Endel

2012-09-01

178

Quark number density at imaginary chemical potential and its extrapolation to large real chemical potential by the effective model  

CERN Document Server

We evaluate quark number densities at imaginary chemical potential by lattice QCD with clover-improved two-flavor Wilson fermion. The quark number densities are extrapolated to the small real chemical potential region by assuming some function forms. The extrapolated quark number densities are consistent with those calculated at real chemical potential with the Taylor expansion method for the reweighting factors. In order to study the large real chemical potential region, we use the two-phase model consisting of the quantum hadrodynamics model for the hadron phase and the entanglement-PNJL model for the quark phase. The quantum hadrodynamics model is constructed to reproduce nuclear saturation properties, while the entanglement-PNJL model reproduces well lattice QCD data for the order parameters such as the Polyakov loop, the thermodynamic quantities and the screening masses. Then, we calculate the mass-radius relation of neutron stars and explore the hadron-quark phase transition with the two-phase model.

Takahashi, Junichi; Ishii, Masahiro; Kouno, Hiroaki; Yahiro, Masanobu

2014-01-01

179

On shrinkage and model extrapolation in the evaluation of clinical center performance  

Science.gov (United States)

We consider statistical methods for benchmarking clinical centers based on a dichotomous outcome indicator. Borrowing ideas from the causal inference literature, we aim to reveal how the entire study population would have fared under the current care level of each center. To this end, we evaluate direct standardization based on fixed versus random center effects outcome models that incorporate patient-specific baseline covariates to adjust for differential case-mix. We explore fixed effects (FE) regression with Firth correction and normal mixed effects (ME) regression to maintain convergence in the presence of very small centers. Moreover, we study doubly robust FE regression to avoid outcome model extrapolation. Simulation studies show that shrinkage following standard ME modeling can result in substantial power loss relative to the considered alternatives, especially for small centers. Results are consistent with findings in the analysis of 30-day mortality risk following acute stroke across 90 centers in the Swedish Stroke Register. PMID:24812420

Varewyck, Machteld; Goetghebeur, Els; Eriksson, Marie; Vansteelandt, Stijn

2014-01-01

180

On shrinkage and model extrapolation in the evaluation of clinical center performance.  

Science.gov (United States)

We consider statistical methods for benchmarking clinical centers based on a dichotomous outcome indicator. Borrowing ideas from the causal inference literature, we aim to reveal how the entire study population would have fared under the current care level of each center. To this end, we evaluate direct standardization based on fixed versus random center effects outcome models that incorporate patient-specific baseline covariates to adjust for differential case-mix. We explore fixed effects (FE) regression with Firth correction and normal mixed effects (ME) regression to maintain convergence in the presence of very small centers. Moreover, we study doubly robust FE regression to avoid outcome model extrapolation. Simulation studies show that shrinkage following standard ME modeling can result in substantial power loss relative to the considered alternatives, especially for small centers. Results are consistent with findings in the analysis of 30-day mortality risk following acute stroke across 90 centers in the Swedish Stroke Register. PMID:24812420

Varewyck, Machteld; Goetghebeur, Els; Eriksson, Marie; Vansteelandt, Stijn

2014-10-01

 
 
 
 
181

THE THREE-DIMENSIONAL STRUCTURE OF AN ACTIVE REGION FILAMENT AS EXTRAPOLATED FROM PHOTOSPHERIC AND CHROMOSPHERIC OBSERVATIONS  

International Nuclear Information System (INIS)

The three-dimensional structure of an active region filament is studied using nonlinear force-free field extrapolations based on simultaneous observations at a photospheric and a chromospheric height. To that end, we used the Si I 10827 Å line and the He I 10830 Å triplet obtained with the Tenerife Infrared Polarimeter at the Vacuum Tower Telescope (Tenerife). The two extrapolations have been carried out independently from each other and their respective spatial domains overlap in a considerable height range. This opens up new possibilities for diagnostics in addition to the usual ones obtained through a single extrapolation from, typically, a photospheric layer. Among those possibilities, this method allows the determination of an average formation height of the He I 10830 Å signal of ?2 Mm above the surface of the Sun. It allows, as well, a cross-check of the obtained three-dimensional magnetic structures to verify a possible deviation from the force-free condition, especially at the photosphere. The extrapolations yield a filament formed by a twisted flux rope whose axis is located at about 1.4 Mm above the solar surface. The twisted field lines make slightly more than one turn along the filament within our field of view, which results in 0.055 turns Mm–1. The convex part of the field lines (as seen from the solar surface) constitutes dips where the plasma can naturally be supported. The obtained three-dimensional magnetic structure of the filamenl magnetic structure of the filament depends on the choice of the observed horizontal magnetic field as determined from the 180° solution of the azimuth. We derive a method to check for the correctness of the selected 180° ambiguity solution.

182

Extrapolation of deep inelastic lepton-nucleon cross sections to SPS energies  

International Nuclear Information System (INIS)

Double differential deep-inelastic lepton scattering cross sections and counting rates are extrapolated from existing data to kinematical regions which will be explored in the Dubna-CERN-Munich-Saclay muon experiments. Uncertainties of this extrapolation procedure are discussed and found to be limited by a factor of about two

183

Fuel cycle design for ITER and its extrapolation to DEMO  

Energy Technology Data Exchange (ETDEWEB)

ITER is the first fusion device that continuously processes DT plasma exhaust and supplies recycled fuel in a closed loop. All the tritium and deuterium in the exhaust are recovered, purified and returned to the tokamak with minimal delay, so that extended burn can be sustained with limited inventory. To maintain the safety of the entire facility, plant scale detritiation systems will also continuously run to remove tritium from the effluents at the maximum efficiency. In this entire tritium plant system, extremely high decontamination factor, that is the ratio of the tritium loss to the processing flow rate, is required for fuel economy and minimized tritium emissions, and the system design based on the state-of-the-art technology is expected to satisfy all the requirements without significant technical challenges. Considerable part of the fusion tritium system will be verified with ITER and its decades of operation experiences. Toward the DEMO plant that will actually generate energy and operate its closed fuel cycle, breeding blanket and power train that caries high temperature and pressure media from the fusion device to the generation system will be the major addition. For the tritium confinement, safety and environmental emission, particularly blanket, its coolant, and generation systems such as heat exchanger, steam generator and turbine will be the critical systems, because the tritium permeation from the breeder and handling large amount of high temperature, high pressure coolant will be further more difficult than that required for ITER. Detritiation of solid waste such as used blanket and divertor will be another issue for both tritium economy and safety. Unlike in the case of ITER that is regarded as experimental facility, DEMO will be expected to demonstrate the safety, reliability and social acceptance issue, even if economical feature is excluded. Fuel and environmental issue to be tested in the DEMO will determine the viability of the fusion as a future energy source. Some of the subjects cannot be expected to be within the extrapolation of ITER technology and require long term efforts paralleling ITER.

Konishi, Satoshi [Institute of Advanced Energy, Kyoto University, Kyoto 611-0011 (Japan)], E-mail: s-konishi@iae.kyoto-u.ac.jp; Glugla, Manfred [Forschungszentrum Karlsruhe, P.O. Box 3640, D 76021 Karlsruhe (Germany); Hayashi, Takumi [Apan Atomic Energy AgencyTokai, Ibaraki 319-0015 Japan (Japan)

2008-12-15

184

Fuel cycle design for ITER and its extrapolation to DEMO  

International Nuclear Information System (INIS)

ITER is the first fusion device that continuously processes DT plasma exhaust and supplies recycled fuel in a closed loop. All the tritium and deuterium in the exhaust are recovered, purified and returned to the tokamak with minimal delay, so that extended burn can be sustained with limited inventory. To maintain the safety of the entire facility, plant scale detritiation systems will also continuously run to remove tritium from the effluents at the maximum efficiency. In this entire tritium plant system, extremely high decontamination factor, that is the ratio of the tritium loss to the processing flow rate, is required for fuel economy and minimized tritium emissions, and the system design based on the state-of-the-art technology is expected to satisfy all the requirements without significant technical challenges. Considerable part of the fusion tritium system will be verified with ITER and its decades of operation experiences. Toward the DEMO plant that will actually generate energy and operate its closed fuel cycle, breeding blanket and power train that caries high temperature and pressure media from the fusion device to the generation system will be the major addition. For the tritium confinement, safety and environmental emission, particularly blanket, its coolant, and generation systems such as heat exchanger, steam generator and turbine will be the critical systems, because the tritium permeation from the breeder and handling large amount of high temperature, andling large amount of high temperature, high pressure coolant will be further more difficult than that required for ITER. Detritiation of solid waste such as used blanket and divertor will be another issue for both tritium economy and safety. Unlike in the case of ITER that is regarded as experimental facility, DEMO will be expected to demonstrate the safety, reliability and social acceptance issue, even if economical feature is excluded. Fuel and environmental issue to be tested in the DEMO will determine the viability of the fusion as a future energy source. Some of the subjects cannot be expected to be within the extrapolation of ITER technology and require long term efforts paralleling ITER

185

Nonparametric reconstruction of the cosmic expansion with local regression smoothing and simulation extrapolation  

CERN Document Server

In this work we present a nonparametric approach, which works on minimal assumptions, to reconstruct the cosmic expansion of the Universe. We propose to combine a locally weighted scatterplot smoothing method and a simulation-extrapolation method. The first one (Loess) is a nonparametric approach that allows to obtain smoothed curves with no prior knowledge of the functional relationship between variables nor of the cosmological quantities. The second one (Simex) takes into account the effect of measurement errors on a variable via a simulation process. For the reconstructions we use as raw data the Union2.1 Type Ia Supernovae compilation, as well as recent Hubble parameter measurements. This work aims to illustrate the approach, which turns out to be a self-sufficient technique in the sense we do not have to choose anything by hand. We examine the details of the method, among them the amount of observational data needed to perform the locally weighted fit which will define the robustness of our reconstructio...

Montiel, Ariadna; Sendra, Irene; Escamilla-Rivera, Celia; Salzano, Vincenzo

2014-01-01

186

Comparison of the performance of two extrapolation chambers for calibration of clinical applicators (90Sr)  

International Nuclear Information System (INIS)

Full text: The 90Sr+90Y applicators utilized in clinical procedures are special sources for brachytherapy, during the treatments of superficial lesions. The applicators have to be periodically calibrated, and the recommended instruments for this kind of calibration are the extrapolation chambers. These instruments are special ionization chambers with possibility of variation of their sensitive volumes. The aim of this work is to compare the performance of two extrapolation chambers with different physical characteristics that were developed at IPEN for the calibration of beta radiation applicators. One of this chambers is a mini-extrapolation chamber that has a 3.0 cm outer diameter, and it is 11.3 cm in length. Furthermore, an aluminized polyester foil is used as the entrance window while the collecting electrode is made of graphited polymethylmethacrylate. The other extrapolation chamber has interchangeable electrodes with body of lucite, collector electrode of 3 and 10 mm in diameter and aluminized polyethylene foils used as the entrance window. These extrapolation chambers were previously utilized as absolute radiation detectors for the calibration of a commercial clinical applicator. In the present work, both extrapolation chambers were calibrated in relation to a standard dermatological applicator calibrated at the American primary standard laboratory, National Institute of Standards and Technology. Extrapolation curves for beta radiation o Extrapolation curves for beta radiation of 90Sr+90Y were obtained and thus the calibration factors were determined for the chambers. Short and medium term stability tests were also realized, using constant interelectrode distances. Finally, the commercial clinical applicator was calibrated using both extrapolation chambers, and the results were compared with those obtained in previous works. (author)

187

Generalized multi-hit dose response model for low-dose extrapolation  

International Nuclear Information System (INIS)

Man is exposed to a variety of natural and synthetic substances that are known to be harmful to experimental animals at high dose levels and consequently are under suspicion of being harmful to humans. The large number of animals required to obtain any positive response at low-dose levels makes it prohibitive to directly estimate the risk at the required dose levels. Thus, the most common method for establishing safe dose levels is to estimate a dose-response curve based on laboratory tests on a limited number of animals at exposure levels well beyond the human usage levels. Then, using such a dose-response curve, one attempts to establish a safe dose based on a statistical low-dose extrapolation procedure. This thesis introduces a generalized multi-hit dose-response model. A biological interpretation of the model in terms of the occurrence of k hits to cause the toxic response, and a statistical interpretation in terms of a gamma tolerance distribution are given. Other dose-response models in the literature are reviewed, with the one-hit or linear model being seen as a special case of the proposed model. The method of maximum likelihood for estimating the parameters of the model, their large sample properties, and their use in risk assessment through extrapolation to low-doses is presented. A method of point estimation of the virtual safe dose, along with its lower 100(1 - ?)% confidence limit is treated. The resulting procedures are then applied to twelve sets of tures are then applied to twelve sets of toxic response data from the literature. Based on these applications, it is seen that the peformance of the model for risk assessment is similar to that of the one-hit model under evidence of near linearity of the dose-response curve in the low-dose range. However, under evidence of concavity (convexity) in the low-dose range, the model is more (less) stringent in its risk assessment

188

Effect of extrapolation length on the phase transformation of epitaxial ferroelectric thin films  

International Nuclear Information System (INIS)

Effects of extrapolation length on the phase transformation of epitaxial ferroelectric thin films on dissimilar cubic substrates have been studied on the basis of the mean-field Landau-Ginzburg-Devonshire (LGD) thermodynamic theory by taking an uneven distribution of the interior stress with thickness into account. It was found that the polarization of epitaxial ferroelectric thin films is strongly dependent on the extrapolation length of films. The physical origin of the extrapolation length during the phase transformation from paraelectric to ferroelectric was revealed in the case of ferroelectric thin films

189

Quelle limite de " bon état écologique " pour les invertébrés benthiques en rivières ? Apport des modèles d'extrapolation spatiale reliant l'indice biologique global normalisé à l'occupation du sol  

Digital Repository Infrastructure Vision for European Research (DRIVER)

For the implementation of the European Water Framework Directive, there is a need of pressures/impacts models allowing to set the priority actions for the restoration. We developed large scale pressures/impacts models, linking aquatic invertebrate index (IBGN) to watershed land cover. We used decision trees method to generate classifications allowing spatial extrapolation. Validated spatial extrapolation models were used to represent on a national scale the probable current ecological status ...

Wasson, J. G.; Villeneuve, B.; Mengin, N.; Pella, H.; Chandesris, A.

2006-01-01

190

Terahertz in-line digital holography of dragonfly hindwing: amplitude and phase reconstruction at enhanced resolution by extrapolation.  

Science.gov (United States)

We report here on terahertz (THz) digital holography on a biological specimen. A continuous-wave (CW) THz in-line holographic setup was built based on a 2.52 THz CO(2) pumped THz laser and a pyroelectric array detector. We introduced novel statistical method of obtaining true intensity values for the pyroelectric array detector's pixels. Absorption and phase-shifting images of a dragonfly's hindwing were reconstructed simultaneously from single in-line hologram. Furthermore, we applied phase retrieval routines to eliminate twin image and enhanced the resolution of the reconstructions by hologram extrapolation beyond the detector area. The finest observed features are 35 ?m width cross veins. PMID:25090537

Rong, Lu; Latychevskaia, Tatiana; Wang, Dayong; Zhou, Xun; Huang, Haochong; Li, Zeyu; Wang, Yunxin

2014-07-14

191

The Fuzzy Logic Method for Simpler Forecasting  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fildes and Makridakis (1998), Makridakis and Hibon (2000), and Fildes (2001) indicate that simple extrapolative forecasting methods that are robust forecast equally as well or better than more complicated methods, i.e. Box-Jenkins and other methods. We study the Direct Set Assignment (DSA) extrapolative forecasting method. The DSA method is a non-linear extrapolative forecasting method developed within the Mamdani Development Framework, and designed to mimic the architecture of a fuzzy logic ...

Jarrett, Jeffrey E.; Plouffe, Jeffrey S.

2011-01-01

192

Melting of “non-magic” argon clusters and extrapolation to the bulk limit  

Energy Technology Data Exchange (ETDEWEB)

The melting of argon clusters Ar{sub N} is investigated by applying a parallel-tempering Monte Carlo algorithm for all cluster sizes in the range from 55 to 309 atoms. Extrapolation to the bulk gives a melting temperature of 85.9 K in good agreement with the previous value of 88.9 K using only Mackay icosahedral clusters for the extrapolation [E. Pahl, F. Calvo, L. Ko?i, and P. Schwerdtfeger, “Accurate melting temperatures for neon and argon from ab initio Monte Carlo simulations,” Angew. Chem., Int. Ed. 47, 8207 (2008)]. Our results for argon demonstrate that for the extrapolation to the bulk one does not have to restrict to magic number cluster sizes in order to obtain good estimates for the bulk melting temperature. However, the extrapolation to the bulk remains a problem, especially for the systematic selection of suitable cluster sizes.

Senn, Florian, E-mail: f.senn@massey.ac.nz; Wiebke, Jonas; Schumann, Ole; Gohr, Sebastian; Schwerdtfeger, Peter, E-mail: p.a.schwerdtfeger@massey.ac.nz [Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Albany, Private Bag 102904, Auckland 0745 (New Zealand); Pahl, Elke, E-mail: e.pahl@massey.ac.nz [Centre for Theoretical Chemistry and Physics, Institute of Natural and Mathematical Sciences, Massey University Albany, Private Bag 102904, Auckland 0745 (New Zealand)

2014-01-28

193

Melting of “non-magic” argon clusters and extrapolation to the bulk limit  

International Nuclear Information System (INIS)

The melting of argon clusters ArN is investigated by applying a parallel-tempering Monte Carlo algorithm for all cluster sizes in the range from 55 to 309 atoms. Extrapolation to the bulk gives a melting temperature of 85.9 K in good agreement with the previous value of 88.9 K using only Mackay icosahedral clusters for the extrapolation [E. Pahl, F. Calvo, L. Ko?i, and P. Schwerdtfeger, “Accurate melting temperatures for neon and argon from ab initio Monte Carlo simulations,” Angew. Chem., Int. Ed. 47, 8207 (2008)]. Our results for argon demonstrate that for the extrapolation to the bulk one does not have to restrict to magic number cluster sizes in order to obtain good estimates for the bulk melting temperature. However, the extrapolation to the bulk remains a problem, especially for the systematic selection of suitable cluster sizes

194

Accuracy of basis-set extrapolation schemes for DFT-RPA correlation energies in molecular calculations  

CERN Document Server

We construct a reference benchmark set for atomic and molecular random-phase-approximation (RPA) correlation energies in a density functional theory (DFT) framework at the complete basis set limit. This set is used to evaluate the accuracy of some popular extrapolation schemes for RPA all-electron molecular calculations. The results indicate that for absolute energies accurate results, clearly outperforming raw data, are achievable with two-point extrapolation schemes based on quintuple- and sextuple-zeta basis sets. Moreover, we show that results in good agreement with the benchmark can also be also obtained by using a semiempirical extrapolation procedure based on quadruple- and quintuple-zeta basis sets. Finally, we analyze the performance of different extrapolation schemes for atomization energies.

Fabiano, E; 10.1007/s00214-012-1278-8

2013-01-01

195

Extrapolation chamber for absolute energy dose rate measurement of beta and soft x radiation  

International Nuclear Information System (INIS)

A new extrapolation chamber is described, which is used as absolute standard for the determination of the absorbed beta radiation dose. The construction simulates a semi-infinite phantom and the absorbed dose to tissue was determined in tissue equivalent material. With a new system of concentric collecting electrodes it is possible to obtain the absorbed dose at the centre of the electrodes, which is extrapolated from five values of the surface of the collecting electrodes. (Author)

196

Loop integration results using numerical extrapolation for a non-scalar integral  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Loop integration results have been obtained using numerical integration and extrapolation. An extrapolation to the limit is performed with respect to a parameter in the integrand which tends to zero. Results are given for a non-scalar four-point diagram. Extensions to accommodate loop integration by existing integration packages are also discussed. These include: using previously generated partitions of the domain and roundoff error guards.

Doncker, E.; Shimizu, Y.; Fujimoto, J.; Yuasa, F.; Kaugars, K.; Cucos, L.; Voorst, J.

2004-01-01

197

A systematic evaluation of the use of physiologically based pharmacokinetic modeling for cross-species extrapolation.  

Science.gov (United States)

Transfer of knowledge along the different phases of drug development is a fundamental process in pharmaceutical research. In particular, cross-species extrapolation between different laboratory animals and further on to first-in-human trials is challenging because of the uncertain comparability of physiological processes. Physiologically based pharmacokinetic (PBPK) modeling allows translation of mechanistic knowledge from one species to another by specifically considering physiological and biochemical differences in between. We here evaluated different knowledge-driven approaches for cross-species extrapolation by systematically incorporating specific model parameter domains of a target species into the PBPK model of a reference species. Altogether, 15 knowledge-driven approaches were applied to murine and human PBPK models of 10 exemplary drugs resulting in 300 different extrapolations. Statistical analysis of the quality of the different extrapolations revealed not only species-specific physiology as the key determinant in cross-species extrapolation but also identified a synergistic effect when considering both kinetic rate constants and gene expression profiles of relevant enzymes and transporters. Moreover, we show that considering species-specific physiology, plasma protein binding, enzyme and transport kinetics, as well as tissue-specific gene expression profiles in PBPK modeling increases accuracy of cross-species extrapolations and thus supports first-in-human trials based on prior preclinical knowledge. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:191-206, 2015. PMID:25393841

Thiel, Christoph; Schneckener, Sebastian; Krauss, Markus; Ghallab, Ahmed; Hofmann, Ute; Kanacher, Tobias; Zellmer, Sebastian; Gebhardt, Rolf; Hengstler, Jan G; Kuepfer, Lars

2015-01-01

198

Using composite flow laws to extrapolate lab data on ice to nature  

Science.gov (United States)

The progressive evolution of the grain size distribution of deforming and recrystallizing Earth materials directly affects their rheological behaviour in terms of composite grain-size-sensitive (GSS, diffusion/grain boundary sliding) and grain-size-insensitive (GSI, dislocation) creep. After time, such microstructural evolution might result in strain progressing at a steady-state balance of mechanisms of GSS and GSI creep. In order to come to a meaningful rheological description of materials deforming by combined GSS and GSI mechanisms, composite flow laws are required that bring together individual, laboratory derived GSS and GSI flow laws, and that include full grain size distributions rather than single mean values representing the grain size. A composite flow law approach including grain size distributions has proven to be very useful in solving discrepancies between microstructural observations in natural calcite mylonites and extrapolations of relatively simple laboratory flow laws (Herwegh et al., 2005, J. Struct Geol., 27, 503-521). In the current study, we used previous and new laboratory data on the creep behavior of water ice to investigate if a composite flow law approach also results in better extrapolation of lab data to nature for ice. The new lab data resulted from static grain-growth experiments and from deformation experiments performed on samples with a starting grain size of either composite flow and to speculate about the evolution towards a balance between GSS and GSI mechanisms. Flow stresses for the natural DML samples were calculated at realistic strain rates between 1E-10/s and 1E-12/s using i) pure GSS-creep, ii) pure GSI-creep, and iii) composite GSI+GSS creep taking the full grain size distribution into account. At a constant strain rate, the contribution of GSS mechanisms to the overall strain rate remains roughly the same along the ice core. Apparently, the change in temperature with depth goes hand in hand with a change in grain size such that there is an overall balance between GSI- and GSS-creep mechanisms. The results show that GSS-mechanisms might well be operative in ice at a range of conditions, but that GSI mechanisms will remain important except at very slow strain rates. In the presentation, new insights emerging from the composite flow law approach to ice as well as pitfalls of the method will be discussed.

de Bresser, Hans; Diebold, Sabrina; Durham, William

2013-04-01

199

High- to low-dose extrapolation: critical determinants involved in the dose response of carcinogenic substances  

International Nuclear Information System (INIS)

Recent investigations on mechanisms of carcinogenesis have demonstrated important quantitative relationships between the induction of neoplasia, the molecular dose of promutagenic DNA adducts and their efficiency for causing base-pair mismatch, and the extent of cell proliferation in target organ. These factors are involved in the multistage process of carcinogenesis, including initiation, promotion, and progression. The molecular dose of DNA adducts can exhibit supralinear, linear, or sublinear relationships to external dose due to differences in absorption, biotransformation, and DNA repair at high versus low doses. In contrast, increased cell proliferation is a common phenomena that is associated with exposures to relatively high doses of toxic chemicals. As such, it enhances the carcinogenic response at high doses, but has little effect at low doses. Since data on cell proliferation can be obtained for any exposure scenario and molecular dosimetry studies are beginning to emerge on selected chemical carcinogens, methods are needed so that these critical factors can be utilized in extrapolation from high to low doses and across species. The use of such information may provide a scientific basis for quantitative risk assessment

200

Extrapolation of Nitrogen Fertiliser Recommendation Zones for Maize in Kisii District Using Geographical Information Systems  

International Nuclear Information System (INIS)

A GIS database was established for fertiliser recommendation domains in Kisii District by using FURP fertiliser trial results, KSS soils data and MDBP climatic data. These are manipulated in ESRI's (Personal Computer Environmental Systems Research Institute) ARCINFO and ARCVIEW softwares. The extrapolations were only done for the long rains season (March- August) with three to four years data. GIS technology was used to cluster fertiliser recommendation domains as a geographical area expressed in terms of variation over space and not limited to the site of experiment where a certain agronomic or economic fertiliser recommendation was made. The extrapolation over space was found to be more representative for any recommendation, the result being digital maps describing each area in the geographical space. From the results of the extrapolations, approximately 38,255 ha of the district require zero Nitrogen (N) fertilisation while 94,330 ha requires 75 kg ha-1 Nitrogen fertilisation during the (March-August) long rains. The extrapolation was made difficult since no direct relationships could be established to occur between the available-N, % Carbon (C) or any of the other soil properties with the obtained yields. Decision rules were however developed based on % C which was the soil variable with values closest to the obtained yields. 3% organic carbon was found to be the boundary between 0 application and 75 kg-N application. GIS techniques made it possible to ation. GIS techniques made it possible to model and extrapolates the results using the available data. The extrapolations still need to be verified with more ground data from fertiliser trials. Data gaps in the soil map left some soil mapping units with no recommendations. Elevation was observed to influence yields and it should be included in future extrapolation by clustering digital elevation models with rainfall data in a spatial model at the district scale

 
 
 
 
201

Extrapolation from large-scale radiation exposures: cancer  

International Nuclear Information System (INIS)

Even though much is known about cancer risk associated with exposure to ionizing radiation, societal demands for detailed risk assessment go far beyond our ability to satisfy them according to customary standards of scientific accuracy. Society's requirement, however, is for the best information available, however good it may be, and not necessarily for the definitive solution to the problem posed. Bayesian methods may be useful for presenting incomplete and varied data and informed scientific opinion in a form suitable for use in societal decision making, while at the same time providing a disciplinary framework for incorporating opinion into scientific recommendations. Inferences about individual cases and their relationship to risk of radiation carcinogenesis provide an especially severe test of the completeness of our understanding of the relationship between exposure and risk. This is particularly true with respect to the distribution of excess risk over time following exposure. Recent work suggests that a standard model often used for projection of risk forward in time, the constant relative excess model, may give a surprisingly accurate picture of time to tumor for a number of cancer sites

202

Extrapolation of animal radionuclide retention data to man: Use of similarity ratios  

International Nuclear Information System (INIS)

A major problem in toxicology is the need for testing a myriad possible substances on several animal species as an aid in establishing standards for man. Particular interest in the problem of extrapolation to man is linked to a need for a method of obtaining transfer coefficients in food-chain models of ecosystems. Such a method could circumvent the necessity to test many species and compounds. Because of their particular interest in radioecology, the authors' studies were initiated using radionuclide retention data available in the literature. Since radionuclide retention should be a function of metabolism it follows that direct or indirect measures could be described by a ''power law'' based on body weight of the organism(s). However, when such power laws have been extended to interspecies comparisons the resulting power coefficients are usually substantially less than the value anticipated and seem to be different for each radionuclide. This paper proposes that interspecies comparisons ought to be based on the proportionality coefficient rather than the power parameter of the power function model and have called pairwise comparisons amongst species ''similarity ratios''. Retention data were examined from five non-ruminant species (including man) where several radionuclides with different physical properties were fed. Subsequently an expression was devised whereby an estimate of biological equilibrium level in man could be calculated using similar estimates from expalculated using similar estimates from experiments using mice, rats or dogs. There are some statistical questions to resolve which have to do with the assumed frequency distribution for estimates of the proportionality coefficient. In addition, repeated use was made of the same data sets. (author)

203

Possible sharp quantization of extrapolated high temperature viscosity- theory and experiment  

CERN Document Server

Quantum effects in material systems are often pronounced at low energies and become insignificant at high temperatures. We find that, perhaps counterintuitively, certain quantum effects may follow the opposite route and become progressively sharper when extrapolated to the "classical" high temperature limit. In the current work, we derive basic relations, extend standard kinetic theory by taking into account a possible fundamental quantum time scale, find new general equalities connecting semi-classical dynamics and thermodynamics to Planck's constant, and compute current correlation functions. Our analysis suggests that, on average, the extrapolated high temperature viscosity of general liquids may tend to a value set by the product of the particle number density ${\\sf n}$ and Planck's constant $h$. We compare this theoretical result with experimental measurements of an ensemble of 23 metallic fluids where this seems to indeed be the case. The extrapolated high temperature viscosity of each of these liquids ...

Nussinov, Z; Blodgett, M; Kelton, K F

2014-01-01

204

Understanding the Larson-Miller parameter. [for extrapolating stress rupture and creep properties of steels and superalloys  

Science.gov (United States)

The Larson-Miller (L-M) method of extrapolating stress rupture and creep results is based on the contention that the absolute temperature-compensated time function should have a unique value for a given material. This value should depend only on the applied stress level. The L-M method has been found satisfactory in the case of many steels and superalloys. The derivation of the L-M relation is discussed, taking into account a power law creep relationship considered by Dorn (1965) and Barrett et al. (1964), a correlation expression reported by Garofalo et al. (1961), and relations concerning the constant C. Attention is given to a verification of the validity of the considered derivation with the aid of suitable materials.

Furillo, F. T.; Purushothaman, S.; Tien, J. K.

1977-01-01

205

The effects of different expansions of the exit distribution on the extrapolation length for linearly anisotropic scattering  

International Nuclear Information System (INIS)

HN and singular eigenfunction methods are used to determine the neutron distribution everywhere in a source-free half space with zero incident flux for a linearly anisotropic scattering kernel. The singular eigenfunction expansion of the method of elementary solutions is used. The orthogonality relations of the discrete and continuous eigenfunctions for linearly anisotropic scattering provides the determination of the expansion coefficients. Different expansions of the exit distribution are used: the expansion in powers of ?, the expansion in terms of Legendre polynomials and the expansion in powers of 1/(1+?). The results are compared to each other. In the second part of our work, the transport equation and the infinite medium Green function are used. The numerical results of the extrapolation length obtained for the different expansions is discussed. (orig.)

206

Estimating the effective extrapolation distance from absorbing bars for security analysis in VVER-440 reactors  

International Nuclear Information System (INIS)

The distance of effective extrapolation of control bars for VVER 440 reactors required for security analysis is estimated using WIMS-D/4 for any work status or reactor stoppage. The methodology employed maintains the flow current rate in the surface of the combustible bar. Values obtained from the extrapolation distance lies between 9 and 13 centimeters. This figure changes with the value of the temperature at the moderator, the boron concentration and its burning. Results are discussed and recommendations for their use during security analysis are given

207

Modeling the length of day and extrapolating the rotation of the Earth  

Science.gov (United States)

The stochastic behavior of the length of day (LOD) process is analyzed and is modeled within statistical accuracy on a time-scale ranging from weeks to millennia by a three-component model comprising a global Brownian motion process, decadal fluctuations, and a 50-day Madden-Julian oscillation. While the model is intended to be phenomenological, some possible physical models underlying the three components are speculated upon. The model is applied to estimate long-range extrapolation errors. For example, it predicts a standard error of 1 h in the clock-time correction ? T for extrapolation by 1,500 years from 500 to 2000 BC.

Huber, Peter J.

2006-09-01

208

Data-based discharge extrapolation: estimating annual discharge for a partially gauged large river basin from its small sub-basins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Large-scale hydrological models and land surface models are by far the only tools for accessing future water resources in climate change impact studies. Those models estimate discharge with large uncertainties, due to the complex interaction between climate and hydrology, the limited quality and availability of data, as well as model uncertainties. A new purely data-based scale-extrapolation method is proposed, to estimate water resources for a large basin solely from selected small su...

Gong, L.

2012-01-01

209

The riskiness of extrapolating short term nutrient retention observations to long term trends in tidal marshes  

Science.gov (United States)

Tidal marshes are among the most dynamic aquatic systems in the world. While astronomical and wind driven tides are the major driver to displace water volumes, rainfall events and evapotranspiration move the overall balance towards water export or import, respectively. Until now, only glimpses of the associated biogeochemical functioning could be obtained, usually at one or several tidal cycles scale, because there was no obvious method to obtain long term water quality data at a high temporal frequency. We have successfully managed, using UV-Vis spectrophotometers in the field, to obtain water quality and flow data on a 15-min frequency for over 20 months in a restored brackish marsh in North Carolina. This marsh was designed to intercept water generated by subsurface drainage of adjacent agricultural land before discharge to the nearby estuary. It is particularly tempting in tidal systems where tides may look very similar from one to the next, to extrapolate results obtained possibly over several days or weeks to a ';seasonal biogeochemical functioning'. The lessons learned from high frequency data at the tidal scale are fascinating, but in the longer term, we have learned that a few and inherently rare rainfall events drove the overall nutrient balance in the marsh. Continuous water quality monitoring is thus essential for two reasons: 1) to observe the short term dynamics, as they are the key to unveil possibly misunderstood biogeochemical processes, and 2) to capture the rare yet essential events which drive the system's response. However, continuous water quality monitoring on a long term basis in harsh coastal environments is not without challenges.

Birgand, F.; Etheridge, J. R.; Burchell, M. R.

2013-12-01

210

Skeletal 212Pb retention following 224Ra injection: extrapolation of animal data to adult humans  

International Nuclear Information System (INIS)

Two methods of interspecies extrapolation, one based on a correlation of skeletal 212Pb/224Ra with body weight, the other based on the mechanistic relationship between skeletal 212Pb/224Ra and reciprocal bone surface-to-volume ratio, lead to the conclusion that the retention of 212Pb in the adult human skeleton is approximately complete a few days after injection. The correlation-based method gives most probable values for 212Pb/224Ra of 1.0 and 1.1 at 2 d and 7 d after injection, compared with values of 1.05 and 1.27 expected at these same times if the retention of 212Pb were complete from the time of injection and if no 212Pb were in the injection solution. The range of values corresponding to one geometric standard error on either side of the most probable value is 0.87 to 1.21 at 2 d post-injection. With the method based on the reciprocal bone surface-to-volume ratio, the best estimate of 212Pb/224Ra at 2 d after injection is 0.88, equal to the value observed in young adult beagles. An alternative interpretation of the results of this latter method leads to the conclusion that retention is complete, with 212Pb/224Ra equal to 1.0 for a 212Pb-free injection solution and 1.1 for a solution containing 212Pb in secular equilibrium with 224Ra. This work, which uses 224Ra daughter produchich uses 224Ra daughter product retention data from mice, rats and dogs following 224Ra injection, provides a scientific foundation for retention assumptions made in the calculation of mean skeletal dose for adult humans. There now appear to be few uncertainties in these latter dose values, stemming from inaccurate retention assumptions; but substantial uncertainties remain in the mean skeletal dose values for juveniles and in the endosteal tissue doses regardless of age

211

Standardization of 131I by 4 ??-? anti-coincidence method  

International Nuclear Information System (INIS)

This work applies 4 ??-? anti-coincidence method, which scarcely need to do efficiency extrapolation, at the same time shorten the measurement process, thus reduced the effects of extrapolation, at the same time shorten the measurement process, thus reduced the effects of extrapolation and half-life corrections. The combined standard uncertainty is about 0.3%

212

Study of the vortex conditions of wings with large sweepback by extrapolation of the Jones method  

Science.gov (United States)

The pockets of separation originating on the leading edges are surrounded by vortex sheets. Their configuration and intensity were determined by four conditions with the JONES approximation, which is itself corrected by a simple logic. Field pressures and stresses were computed for different cases and are compared with test results (pure deltas, swallow tails, truncations, strakes, ducks, fuselage).

Hirsch, P.

1980-01-01

213

Infinite Volume Extrapolations of Finite Cluster Calculations, ---How Correct are These?  

CERN Document Server

Extrapolations of numerical data obtained from finite cluster calculations to the infinite volume limit can often give incorrect results. We discuss four separate cases: (a) the intensity of the lowest two-photon absorption in the infinite polyene, (b) bond alternation in the infinite polyene, (c) Cooper type pairing in the simple Hubbard model, and (d) pairing within the extended Hubbard model.

Mazumdar, S; Guo, D; Ung, K C; Gammel, J T

1993-01-01

214

Extrapolation of multiplicity distribution in p+p(\\bar{p}) collisions to LHC energies  

Science.gov (United States)

The multiplicity (Nch) and pseudorapidity distribution (dNch/d?) of primary charged particles in p + p collisions at Large Hadron Collider (LHC) energies of \\sqrt{s} = 10 and 14 TeV are obtained from extrapolation of existing measurements at lower \\sqrt{s}. These distributions are then compared to calculations from PYTHIA and PHOJET models. The existing \\sqrt{s} measurements are unable to distinguish between a logarithmic and power law dependence of the average charged particle multiplicity (langNchrang) on \\sqrt{s}, and their extrapolation to energies accessible at LHC give very different values. Assuming a reasonably good description of inclusive charged particle multiplicity distributions by negative binomial distribution (NBD) at lower \\sqrt{s} to hold for LHC energies, we observe that the logarithmic \\sqrt{s} dependences of langNchrang are favored by the models at midrapidity. The dNch/d? versus ? distributions for the existing measurements are found to be reasonably well described by a function with three parameters which accounts for the basic features of the distribution, height at midrapidity, central rapidity plateau and the higher rapidity fall-off. Extrapolation of these parameters as a function of \\sqrt{s} is used to predict the pseudorapidity distributions of charged particles at LHC energies. dNch/d? calculations from PYTHIA and PHOJET models are found to be lower compared to those obtained from the extrapolated dNch/d? versus ? distributions for a broad ? range.

Dash, Ajay Kumar; Mohanty, Bedangadas

2010-02-01

215

EXTRAPOLATION MODELING OF AEROSOL DEPOSITION IN HUMAN AND LABORATORY RAT LUNGS  

Science.gov (United States)

Laboratory test animals are often used as surrogates in exposure studies to assess the potential threat to human health following inhalation of airborne contaminants. o aid in the interpretation and extrapolation of data to man, dosimetric considerations need to be addressed. her...

216

Regression models in the determination of the absorbed dose with extrapolation chamber for ophthalmological applicators  

International Nuclear Information System (INIS)

The absorbed dose for equivalent soft tissue is determined,it is imparted by ophthalmologic applicators, (90 Sr/90 Y, 1850 MBq) using an extrapolation chamber of variable electrodes; when estimating the slope of the extrapolation curve using a simple lineal regression model is observed that the dose values are underestimated from 17.7 percent up to a 20.4 percent in relation to the estimate of this dose by means of a regression model polynomial two grade, at the same time are observed an improvement in the standard error for the quadratic model until in 50%. Finally the global uncertainty of the dose is presented, taking into account the reproducibility of the experimental arrangement. As conclusion it can infers that in experimental arrangements where the source is to contact with the extrapolation chamber, it was recommended to substitute the lineal regression model by the quadratic regression model, in the determination of the slope of the extrapolation curve, for more exact and accurate measurements of the absorbed dose. (Author)

217

Scaling and chiral extrapolation of pion mass and decay constant with maximally twisted mass QCD  

International Nuclear Information System (INIS)

We present an update of the results for pion mass and pion decay constant as obtained by the ETM collaboration in large scale simulations with maximally twisted mass fermions and two mass degenerate flavours of light quarks. We discuss the continuum, chiral and infinite volume extrapolation of these quantities as well as the extraction of low energy constants, and investigate possible systematic uncertainties. (orig.)

218

Corrosion allowances for sodium heated steam generators: evaluation of effects and extrapolation to component life time  

International Nuclear Information System (INIS)

Steam generator tubes are subjected to two categories of corrosion; metal/sodium reactions and metal/water-steam interactions. Referring to these environmental conditions the relevant parameters are discussed. The influences of these parameters on the sodium corrosion and water/steam-reactions are evaluated. Extrapolations of corrosion values to steam generator design conditions are performed and discussed in detail. (author)

219

Terahertz in-line digital holography of dragonfly hindwing: amplitude and phase reconstruction at enhanced resolution by extrapolation  

CERN Document Server

We report here on terahertz (THz) digital holography on a biological specimen. A continuous-wave (CW) THz in-line holographic setup was built based on a 2.52 THz CO2 pumped THz laser and a pyroelectric array detector. We introduced novel statistical method of obtaining true intensity values for the pyroelectric array detector's pixels. Absorption and phase-shifting images of a dragonfly's hind wing were reconstructed simultaneously from single in-line hologram. Furthermore, we applied phase retrieval routines to eliminate twin image and enhanced the resolution of the reconstructions by hologram extrapolation beyond the detector area. The finest observed features are 35 {\\mu}m width cross veins.

Rong, Lu; Wang, Dayong; Zhou, Xun; Huang, Haochong; Li, Zeyu; Wang, Yunxin

2014-01-01

220

{sup 131}I-CRTX internal dosimetry: animal model and human extrapolation  

Energy Technology Data Exchange (ETDEWEB)

Snake venoms molecules have been shown to play a role not only in the survival and proliferation of tumor cells but also in the processes of tumor cell adhesion, migration and angiogenesis. {sup 125}I-Crtx, a radiolabeled version of a peptide derived from Crotalus durissus terrificus snake venom, specifically binds to tumor and triggers apoptotic signalling. At the present work, {sup 125}I-Crtx biokinetic data (evaluated in mice bearing Erlich tumor) were treated by MIRD formalism to perform Internal Dosimetry studies. Doses in several organs of mice were determinate, as well as in implanted tumor, for {sup 131}I-Crtx. Doses results obtained for animal model were extrapolated to humans assuming a similar concentration ratio among various tissues between mouse and human. In the extrapolation, it was used human organ masses from Cristy/Eckerman phantom. Both penetrating and non-penetrating radiation from {sup 131}I in the tissue were considered in dose calculations. (author)

Andrade, Henrique Martins de; Ferreira, Andrea Vidal; Soares, Marcella Araugio; Silveira, Marina Bicalho; Santos, Raquel Gouvea dos [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN-MG), Belo Horizonte, MG (Brazil)], e-mail: hma@cdtn.br

2009-07-01

 
 
 
 
221

{sup 131}I-SPGP internal dosimetry: animal model and human extrapolation  

Energy Technology Data Exchange (ETDEWEB)

Scorpaena plumieri is commonly called moreia-ati or manganga and is the most venomous and one of the most abundant fish species of the Brazilian coast. Soprani 2006, demonstrated that SPGP - an isolated protein from S. plumieri fish- possess high antitumoral activity against malignant tumours and can be a source of template molecules for the development (design) of antitumoral drugs. In the present work, Soprani's {sup 125}ISPGP biokinetic data were treated by MIRD formalism to perform Internal Dosimetry studies. Absorbed doses due to the {sup 131}I-SPGP uptake were determinate in several organs of mice, as well as in the implanted tumor. Doses obtained for animal model were extrapolated to humans assuming a similar ratio for various mouse and human tissues. For the extrapolation, it was used human organ masses from Cristy/Eckerman phantom. Both penetrating and non-penetrating radiation from {sup 131}I were considered. (author)

Andrade, Henrique Martins de; Ferreira, Andrea Vidal; Soprani, Juliana; Santos, Raquel Gouvea dos [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN-MG), Belo Horizonte, MG (Brazil)], e-mail: hma@cdtn.br; Figueiredo, Suely Gomes de [Universidade Federal do Espirito Santo, (UFES), Vitoria, ES (Brazil). Dept. de Ciencias Fisiologicas. Lab. de Quimica de Proteinas

2009-07-01

222

EVALUATION OF THE ADEQUACY OF THE WIND SPEED EXTRAPOLATION LAWS FOR TWO DIFFERENT ROUGHNESS METEOROLOGICAL SITES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Increasing knowledge on wind shear models to strengthen their reliability appears as a crucial issue, markedly for energy investors to accurately predict the average wind speed at different turbine hub heights and thus the expected wind energy output. This is particularly helpful during the feasibility study to abate the costs of a wind power project. The extrapolation laws were found to provide the finest representation of the wind speed according to heights, thus avoiding installation of ta...

Dalila Khalfa; Abdelouaheb Benretem; Lazher Herous; Issam Meghlaoui

2014-01-01

223

Opportunities for improving techniques for interspecies extrapolation in the risk assessment process.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Quantitative estimates of human carcinogenic risk from chemical exposure are currently derived primarily from linearized multistage model analyses of the tumor response as observed in chronic laboratory animal bioassays versus administered dose. The numerous ad hoc assumptions that provide a rationale for this generic approach to carcinogenic risk assessment can only be evaluated critically when mechanistic data directly relevant to the low-dose and interspecies extrapolation problems are ava...

Gibson, J. E.; Starr, T. B.

1988-01-01

224

Subsequent entry biologics (biosimilars in Canada: approaches to interchangeability and the extrapolation of indications and uses  

Directory of Open Access Journals (Sweden)

Full Text Available The principles Health Canada use when extrapolating the indications and uses of a biosimilar product subsequent to a single clinical trial or limited number and scope of clinical trials during product development are discussed. The principles underlying the regulatory framework for Subsequent Entry Biologics (SEBs or biosimilars in Canada explain the position taken by the regulator in respect of the substitutability and/or interchangeability of SEBs.

Agnes V Klein

2014-11-01

225

Geospatial Simulation Based On Cellular Automata in Extrapolating Land-Use Changes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The dynamics changes of land-use and their impact are a natural responses to human activities. These responses need to be understood in order to determine a proper management in the future. The aim of this research is to formulate the rules required for developing a Cellular Automata (CA) model so that the simulation of geospatial data are able to produce an extrapolation map of land-use changes from 2012 until 2037. This research employed CA-simulation and modeling. The ...

Paharuddin

2014-01-01

226

Negative-Dimensional Group Extrapolation and Dualities in N=1 Supersymmetric Gauge Theories  

Science.gov (United States)

We point out that the similarities in N=1 supersymmetric SO, SP gauge theories can be explained by using the trick of extrapolating the groups to the negative dimensions. One of the advantages of this trick is that anomaly matching is automatically satisfied. We also give a comment on the problem which one encounters when applying the trick of negative-dimensional group to Spin group duality.

Maru, Nobuhito; Kitakado, Shinsaku

227

Numerically extrapolated discrete layer-peeling algorithm for synthesis of nonuniform fiber Bragg gratings.  

Science.gov (United States)

The discrete layer-peeling algorithm (DLPA) requires to discretize the continuous medium into discrete reflectors to synthesize nonuniform fiber Bragg gratings (FBG), and the discretization step of this discrete model should be sufficiently small for synthesis with high accuracy. However, the discretization step cannot be made arbitrarily small to decrease the discretization error, because the number of multiplications needed with the DLPA is proportional to the inverse square of the layer thickness. We propose a numerically extrapolated time domain DLPA (ETDLPA) to resolve this tradeoff between the numerical accuracy and the computational complexity. The accuracy of the proposed ETDLPA is higher than the conventional time domain DLPA (TDLPA) by an order of magnitude or more, with little computational overhead. To be specific, the computational efficiency of the ETDLPA is achieved through numerical extrapolation, and each addition of the extrapolation depth improves the order of accuracy by one. Therefore, the ETDLPA provides us with computationally more efficient and accurate methodology for the nonuniform FBG synthesis than the TDLPA. PMID:21643075

Choi, Youngchol; Chun, Joohwan; Bae, Jinho

2011-04-25

228

J-85 jet engine noise measured in the ONERA S1 wind tunnel and extrapolated to far field  

Science.gov (United States)

Noise from a J-85 turbojet with a conical, convergent nozzle was measured in simulated flight in the ONERA S1 Wind Tunnel. Data are presented for several flight speeds up to 130 m/sec and for radiation angles of 40 to 160 degrees relative to the upstream direction. The jet was operated with subsonic and sonic exhaust speeds. A moving microphone on a 2 m sideline was used to survey the radiated sound field in the acoustically treated, closed test section. The data were extrapolated to a 122 m sideline by means of a multiple-sideline source-location method, which was used to identify the acoustic source regions, directivity patterns, and near field effects. The source-location method is described along with its advantages and disadvantages. Results indicate that the effects of simulated flight on J-85 noise are significant. At the maximum forward speed of 130 m/sec, the peak overall sound levels in the aft quadrant were attentuated approximately 10 dB relative to sound levels of the engine operated statically. As expected, the simulated flight and static data tended to merge in the forward quadrant as the radiation angle approached 40 degrees. There is evidence that internal engine or shock noise was important in the forward quadrant. The data are compared with published predictions for flight effects on pure jet noise and internal engine noise. A new empirical prediction is presented that relates the variation of internally generated engine noise or broadband shock noise to forward speed. Measured near field noise extrapolated to far field agrees reasonably well with data from similar engines tested statically outdoors, in flyover, in a wind tunnel, and on the Bertin Aerotrain. Anomalies in the results for the forward quadrant and for angles above 140 degrees are discussed. The multiple-sideline method proved to be cumbersome in this application, and it did not resolve all of the uncertainties associated with measurements of jet noise close to the jet. The simulation was complicated by wind-tunnel background noise and the propagation of low frequency sound around the circuit.

Soderman, Paul T.; Julienne, Alain; Atencio, Adolph, Jr.

1991-01-01

229

Energy extrapolation schemes for adaptive multi-scale molecular dynamics simulations  

Science.gov (United States)

This paper evaluates simple schemes to extrapolate potential energy values using the set of energies and forces extracted from a molecular dynamics trajectory. In general, such a scheme affords the maximum amount of information about a molecular system at minimal computational cost. More specifically, schemes like this are very important in the field of adaptive multi-scale molecular dynamics simulations. In this field, often the computation of potential energy values at certain trajectory points is not required for the simulation itself, but solely for the a posteriori analysis of the simulation data. Extrapolating the values at these points from the available data can save considerable computational time. A set of extrapolation schemes are employed based on Taylor series and central finite difference approximations. The schemes are first tested on the trajectories of molecular systems of varying sizes, obtained at MM and QM level using velocity-Verlet integration with standard simulation time steps. Remarkably good accuracy was obtained with some of the approximations, while the failure of others can be explained in terms of the distinct features of a molecular dynamics trajectory. We have found that, for a Taylor expansion of the potential energy, both a first and a second order truncation exhibit errors that grow with system size. In contrast, the second order central finite difference approximation displays an accuracy that is independent of the size of the system, while giving a very good estimate of the energy, and costing as little as a first order truncation of the Taylor series. A fourth order central finite difference approximation requires more input data, which is not always available in adaptive multi-scale simulations. Furthermore, this approximation gives errors of similar magnitude or larger than its second order counterpart, at standard simulation time steps. This leads to the conclusion that a second order central finite difference approximation is the optimal choice for energy extrapolation from molecular dynamics trajectories. This finding is confirmed in a final application to the analysis of an adaptive multi-scale simulation.

Fleurat-Lessard, Paul; Michel, Carine; Bulo, Rosa E.

2012-08-01

230

Radioactive waste produced by DEMO and commercial fusion reactors extrapolated from ITER and advanced data bases  

International Nuclear Information System (INIS)

The radioactive wastes that would be produced in demonstration (DEMO) and commercial (CFR) fusion reactors which could be extrapolated from the design data base that will be provided by ITER and its supporting R ampersand D and from a design data base supplemented by advanced physics and advanced materials R ampersand D programs are identified and characterized in terms of a number of possible criteria for near-surface burial. The results indicate that there is a possibility that all fusion wastes could satisfy a ''low level'' waste criterion for ''near-surface'' burial

231

Extrapolating glacier mass balance to the mountain range scale: the European Alps 1900–2100  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study addresses the extrapolation of single glacier mass balance measurements to the mountain range scale and aims at deriving time series of area-averaged mass balance and ice volume change for all glaciers in the European Alps for the period 1900–2100. Long-term mass balance series for 50 Swiss glaciers based on a combination of field data and modelling, and WGMS data for glaciers in Austria, France and Italy are used. A complete glacier inventory is available for the year 2003. Mass...

Huss, M.

2012-01-01

232

Extrapolation of the Dutch 1 MW tunable free electron maser to a 5 MW ECRH source  

International Nuclear Information System (INIS)

A Free Electron Maser (FEM) is now under construction at the FOM Institute (Rijnhuizen) Netherlands with the goal of producing 1 MW long pulse to CW microwave output in the range 130 GHz to 250 GHz with wall plug efficiencies of 50% (Verhoeven, et al EC-9 Conference). An extrapolated version of this device is proposed which by scaling up the beam current, would produce microwave power levels of up to 5 MW CW in order to reduce the cost per watt and increase the power per module, thus providing the fusion community with a practical ECRH source

233

CHARACTERISTICS OF THE H-MODE PEDESTAL AND EXTRAPOLATION TO ITER  

International Nuclear Information System (INIS)

A271 CHARACTERISTICS OF THE H-MODE PEDESTAL AND EXTRAPOLATION TO ITER. The peeling-ballooning mode model for edge stability along with a model for the H-mode transport barrier width is used as an approach to estimating the H-mode pedestal conditions in ITER. Scalings of the barrier width based on ion-orbit loss, neutral penetration, and turbulence suppression are examined and empirical scalings of the barrier width are presented. An empirical scaling for the pedestal ? is derived based on ideas from stability and the empirical width scaling. The impact of the stability model and other factors on ELM size is discussed

234

Two photon decay of the pseudoscalars, the extrapolation to the mass-shell  

CERN Document Server

The extrapolation of the decay amplitude of the pseudoscalar mesons into two photons from the soft meson limit where it is obtained from the axial anomaly to the mass-shell involves the contribution of the 0 minus continuum. The corrections to the soft-meson limit is estimated and turns out to be very large for the eta and eta'. The results, however, remain consistent with the values of the singlet-octet mixing angle theta =-19.5 degree and the ratio f8/fpi=1.25 obtained from the chiral perturbation theory.

Nasrallah, N F

2001-01-01

235

Magnetic form factors of the octet baryons from lattice QCD and chiral extrapolation  

Energy Technology Data Exchange (ETDEWEB)

We present a 2+1-flavor lattice QCD calculation of the electromagnetic Dirac and Pauli form factors of the octet baryons. The magnetic Sachs form factor is extrapolated at six fixed values of Q{sup 2} to physical pseudoscalar masses and infinite volume using a formulation based on heavy baryon chiral perturbation theory with finite-range regularization. We properly account for omitted disconnected quark contractions using a partially-quenched effective field theory formalism. The results compare well with the experimental form factors of the nucleon and the magnetic moments of the octet baryons.

Shanahan, P.E.; Thomas, A.W.; Young, R.D.; Zanotti, J.M. [Adelaide Univ. (Australia). School of Chemistry and Physics; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo (Japan); Pleiter, D. [Forschungszentrum Juelich GmbH (Germany). Juelich Supercomputing Centre (JSC); Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Stueben, H. [Hamburg Univ. (Germany). Regionales Rechenzentrum; Collaboration: CSSM and QCDSF/UKQCD Collaborations

2014-01-15

236

Is the Climate Right for Pleistocene Rewilding? Using Species Distribution Models to Extrapolate Climatic Suitability for Mammals across Continents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Species distribution models (SDMs) are increasingly used for extrapolation, or predicting suitable regions for species under new geographic or temporal scenarios. However, SDM predictions may be prone to errors if species are not at equilibrium with climatic conditions in the current range and if training samples are not representative. Here the controversial “Pleistocene rewilding” proposal was used as a novel example to address some of the challenges of extrapolating modeled species-cli...

Richmond, Orien M. W.; Mcentee, Jay P.; Hijmans, Robert J.; Brashares, Justin S.

2010-01-01

237

Improved spatial resolution in time-resolved transillumination imaging using temporal extrapolation with the cumulant expansion solution to the transport equation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Este artículo presenta resultados de un método para la formación de imágenes resueltas temporalmente mediante la transmisión de luz usando una extrapolación temporal. La extrapolación temporal se realiza mediante la solución a la ecuación de transporte mediante la expansión en cumulantes. Los result [...] ados obtenidos se comparan con los resultados del mismo método pero usando la solución mediante la aproximación de difusión. Se encuentra que los resultados son consistentes pero la el método usando la expansión en cumulantes da mejor resolución, en un factor de aproximadamente 3, para el proceso de formación de imágenes, esto debido a que da una mejor estimación de la contribución de los fotones con tiempos de integración menores. Abstract in english This paper presents results of a time-resolved transillumination imaging method using temporal extrapolation. The temporal extrapolation is performed with the cumulant expansion solution to the transport equation. The results obtained are compared to results of the same method but using the diffusio [...] n approximation solution. It is found that the results are consistent but that the cumulant expansion method gives better resolution, by a factor of approximately 3, for the imaging process, because it gives a better estimation of the photon contribution for shorter integration times.

E., Ortiz-Rascón; N. C., Bruce; A. A., Rodríguez-Rosales; J., Garduño-Mejía; R., Ortega-Martínez.

2014-02-01

238

Data-based discharge extrapolation: estimating annual discharge for a partially gauged large river basin from its small sub-basins  

Directory of Open Access Journals (Sweden)

Full Text Available Large-scale hydrological models and land surface models are by far the only tools for accessing future water resources in climate change impact studies. Those models estimate discharge with large uncertainties, due to the complex interaction between climate and hydrology, the limited quality and availability of data, as well as model uncertainties. A new purely data-based scale-extrapolation method is proposed, to estimate water resources for a large basin solely from selected small sub-basins, which are typically two-orders-of-magnitude smaller than the large basin. Those small sub-basins contain sufficient information, not only on climate and land surface, but also on hydrological characteristics for the large basin In the Baltic Sea drainage basin, best discharge estimation for the gauged area was achieved with sub-basins that cover 2–4% of the gauged area. There exist multiple sets of sub-basins that resemble the climate and hydrology of the basin equally well. Those multiple sets estimate annual discharge for gauged area consistently well with 5% average error. The scale-extrapolation method is completely data-based; therefore it does not force any modelling error into the prediction. The multiple predictions are expected to bracket the inherent variations and uncertainties of the climate and hydrology of the basin. The method can be applied in both un-gauged basins and un-gauged periods with uncertainty estimation.

L. Gong

2012-06-01

239

Extrapolating SMBH correlations down the mass scale: the case for IMBHs in globular clusters  

CERN Document Server

Empirical evidence for both stellar mass black holes M_bh10^5 M_sun) is well established. Moreover, every galaxy with a bulge appears to host a SMBH, whose mass is correlated with the bulge mass, and even more strongly with the central stellar velocity dispersion sigma_c, the `M-sigma' relation. On the other hand, evidence for "intermediate-mass" black holes (IMBHs, with masses in the range 1^2 - 10^5 M_sun) is relatively sparse, with only a few mass measurements reported in globular clusters (GCs), dwarf galaxies and low-mass AGNs. We explore the question of whether globular clusters extend the M-sigma relationship for galaxies to lower black hole masses and find that available data for globular clusters are consistent with the extrapolation of this relationship. We use this extrapolated M-sigma relationship to predict the putative black hole masses of those globular clusters where existence of central IMBH was proposed. We discuss how globular clusters can be used as a constraint on theories making specific...

Safonova, Margarita

2009-01-01

240

Problems With the Collection and Interpretation of Asian-American Health Data: Omission, Aggregation, and Extrapolation  

Science.gov (United States)

Asian-American citizens are the fastest growing racial/ethnic group in the United States. Nevertheless, data on Asian American health are scarce, and many health disparities for this population remain unknown. Much of our knowledge of Asian American health has been determined by studies in which investigators have either grouped Asian-American subjects together or examined one subgroup alone (e.g., Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese). National health surveys that collect information on Asian-American race/ethnicity frequently omit this population in research reports. When national health data are reported for Asian-American subjects, it is often reported for the aggregated group. This aggregation may mask differences between Asian-American subgroups. When health data are reported by Asian American subgroup, it is generally reported for one subgroup alone. In the Ni-Hon-San study, investigators examined cardiovascular disease in Japanese men living in Japan (Nippon; Ni), Honolulu, Hawaii (Hon), and San Francisco, CA (San). The findings from this study are often incorrectly extrapolated to other Asian-American subgroups. Recommendations to correct the errors associated with omission, aggregation, and extrapolation include: oversampling of Asian Americans, collection and reporting of race/ ethnicity data by Asian-American subgroup, and acknowledgement of significant heterogeneity among Asian American subgroups when interpreting data. PMID:22625997

Holland, Ariel T.; Palaniappan, Latha P.

2015-01-01

 
 
 
 
241

An analytic formula for the extrapolated range of electrons in condensed materials  

International Nuclear Information System (INIS)

A single analytic formula for the extrapolated range rex of electrons in condensed materials of atomic numbers from 4 to 92 is given. It has the form of the product of the continuous-slowing-down approximation (CSDA) range r0 and a factor fd related to multiple scattering detours. The factor fd is expressed as a function of incident electron energy T0 and atomic number Z of medium. Values of adjustable parameters in fd have been optimized for data on the ratio rex/r0, in which the Monte Carlo evaluated values of Tabata et al. [Nucl. Instr. Meth. B 95 (1995) 289] (from 0.1 to 100 MeV) and experimental data collected from literature (from 1 keV to 0.1 MeV) for rex have been used together with NIST-database values of r0. For r0 in the extrapolated-range formula, accurate database values or an approximate analytic expression developed as a function of T0, Z, atomic weight A and mean excitation energy I of medium can be used. The maximum deviation of the resultant formula from the Monte Carlo data is about 2% for either option of r0. The determination of the expression for fd at energies below 0.1 MeV is tentative. By using an effective atomic number and atomic weight, the formula can also be applied to light compounds and mixtures. (orig.)

242

Testing magnetofrictional extrapolation with the Titov-D\\'emoulin model of solar active regions  

CERN Document Server

We examine the nonlinear magnetofrictional extrapolation scheme using the solar active region model by Titov and D\\'emoulin as test field. This model consists of an arched, line-tied current channel held in force-free equilibrium by the potential field of a bipolar flux distribution in the bottom boundary. A modified version, having a parabolic current density profile, is employed here. We find that the equilibrium is reconstructed with very high accuracy in a representative range of parameter space, using only the vector field in the bottom boundary as input. Structural features formed in the interface between the flux rope and the surrounding arcade-"hyperbolic flux tube" and "bald patch separatrix surface"-are reliably reproduced, as are the flux rope twist and the energy and helicity of the configuration. This demonstrates that force-free fields containing these basic structural elements of solar active regions can be obtained by extrapolation. The influence of the chosen initial condition on the accuracy...

Valori, G; Török, T; Titov, V S

2010-01-01

243

Accurate ab initio-based analytical potential energy function for S2 (ã1?g) via extrapolation to the complete basis set limit  

Science.gov (United States)

The potential energy curves (PECs) of the first electronic excited state of S2(ã1?g) are calculated employing a multi-reference configuration interaction method with the Davidson correction in combination with a series of correlation-consistent basis sets from Dunning: aug-cc-pVXZ (X = T, Q, 5, 6). In order to obtain PECs with high accuracy, PECs calculated with aug-cc-pV(Q, 5)Z basis sets are extrapolated to the complete basis set limit. The resulting PECs are then fitted to the analytical potential energy function (APEF) using the extended Hartree-Fock approximate correlation energy method. By utilizing the fitted APEF, accurate and reliable spectroscopic parameters are obtained, which are consistent with both experimental and theoretical results. By solving the Schrödinger equation numerically with the APEFs obtained at the AV6Z and the extrapolated AV(Q, 5)Z level of theory, we calculate the complete set of vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants. Project supported by the National Natural Science Foundation of China (Grant Nos. 11304185 and 11074151).

Zhang, Lu-Lu; Gao, Shou-Bao; Meng, Qing-Tian; Song, Yu-Zhi

2015-01-01

244

Modeling the systemic retention of beryllium in rat. Extrapolation to human  

International Nuclear Information System (INIS)

In this work, we analyzed different approaches, assayed in order to numerically describe the systemic behaviour of Beryllium. The experimental results used in this work, were previously obtained by Furchner et al. (1973), using Sprague-Dawley rats, and others animal species. Furchner's work includes the obtained model for whole body retention in rats, but not for each target organ. In this work we present the results obtained by modeling the kinetic behaviour of Beryllium in several target organs. The results of this kind of models were used in order to establish correlations among the estimated kinetic constants. The parameters of the model were extrapolated to humans and, finally, compared with others previously published. (Author) 12 refs

245

Extrapolation-Directed Crossover Considering Sampling Bias in Real-coded Genetic Algorithm  

Science.gov (United States)

We propose a new Real-coded GA(RCGA) using the combination of two crossovers, UNDX-m and EDX. The search region of UNDX-m is biased to the inside area that the population of the RCGA covers. Because of this search bias, the GA using UNDX-m causes stagnation of its search if the cost function has a kind of structure, so called, a ridge structure or a multiple-peak structure. In order to overcome this stagnation, we propose a new crossover EDX, whose search is biased toward extrapolative one. Experimental results show that RCGA with EDX can deal with both ridge-structure function whose dimension reaches more than hundreds and multiple-peak function whose optimum resides at the corner of the search area.

Sakuma, Jun; Kobayashi, Shigenobu

246

The Richardson extrapolation technique for quasilinear parabolic singularly perturbed convection-diffusion equations  

International Nuclear Information System (INIS)

The Dirichlet problem is considered for a quasilinear singularly perturbed parabolic convection-diffusion equation on a rectangular domain. For this problem classical finite difference (nonlinear) schemes on piecewise uniform meshes condensing in the boundary layer converge e-uniformly at a rate that is at best first-order. Using a Richardson extrapolation technique, we construct an improved (nonlinear) scheme that is ?-uniformly convergent at the rate O((N-1 ln N)2 + N-20), where N and N0 define the number of nodes in the spatial and time meshes, respectively. This nonlinear scheme is used in the construction of a linearized scheme where at each time level the nonlinear term is evaluated using the computed solution from the previous time level. Furthermore, using the linearized and nonlinear improved schemes, we construct a linearized improved Richardson scheme that converges e-uniformly at the rate O((N-1 ln N)2 + N-q0), where q ? 2

247

Hematological responses after inhaling 238PuO2: An extrapolation from beagle dogs to humans  

International Nuclear Information System (INIS)

The alpha emitter plutonium-238 (238Pu), which is produced in uranium-fueled, light-water reactors, is used as a thermoelectric power source for space applications. Inhalation of a mixed oxide form of Pu is the most likely mode of exposure of workers and the general public. Occupational exposures to 238PuO2 have occurred in association with the fabrication of radioisotope thermoelectric generators. Organs and tissue at risk for deterministic and stochastic effects of 238Pu-alpha irradiation include the lung, liver, skeleton, and lymphatic tissue. Little has been reported about the effects of inhaled 238PuO2 on peripheral blood cell counts in humans. The purpose of this study was to investigate hematological responses after a single inhalation exposure of Beagle dogs to alpha-emitting 238PuO2 particles and to extrapolate results to humans

248

Flow Forecasting in Drainage Systems with Extrapolated Radar Rainfall Data and Auto Calibration on Flow Observations  

DEFF Research Database (Denmark)

Forecasting of flows, overflow volumes, water levels, etc. in drainage systems can be applied in real time control of drainage systems in the future climate in order to fully utilize system capacity and thus save possible construction costs. An online system for forecasting flows and water levels in a small urban catchment has been developed. The forecast is based on application of radar rainfall data, which by a correlation based technique, is extrapolated with a lead time up to two hours. The runoff forecast in the drainage system is based on a fully distributed MOUSE model which is auto-calibrated on flow measurements in order to produce the best possible forecast for the drainage system at all times. The system shows great potential for the implementation of real time control in drainage systems and forecasting flows and water levels.

Thorndahl, SØren Liedtke; Grum, M.

2011-01-01

249

Modeling of systematic retention of beryllium in rats. Extrapolation to humans  

International Nuclear Information System (INIS)

In this work, we analyzed different approaches, assayed in order to numerically describe the systemic behaviour of Beryllium. The experimental results used in this work, were previously obtained by Furchner et al. (1973), using Sprague-Dawley rats, and other animal species. Furchner's work includes the obtained model for whole body retention in rats but not for each target organ. In this work we present the results obtained by modeling the kinetic behaviour of Beryllium in several target organs. The results of this kind of models were used in order to establish correlations among the estimated kinetic constants. The parameters of the model were extrapolated to humans and, finally, compared with other previously published

250

Integrated scenario with type-III ELMy H-mode edge: extrapolation to ITER  

International Nuclear Information System (INIS)

One of the most severe problems for fusion reactors is the power load on the plasma facing components. The challenge is to develop operation scenarios, which combine sufficient energy confinement with benign heat loads to the plasma facing components. The radiative type-III ELMy H-mode seems a possible solution for such an integrated ITER scenario. Nitrogen seeded type-III ELMy H-modes for the standard inductive scenario and the high beta stationary hybrid scenario are investigated with respect to their transient and steady-state power fluxes to the divertor, confinement properties, edge operational space, core operational space, plasma purity and MHD behaviour. A large database of highly radiative type-III ELMy H-modes on JET is used for extrapolations to ITER. On this basis the transient heat load should be acceptable for ITER. It was found that the scaling of the confinement time with respect to the ion gyroradius is close to the gyro-Bohm scaling. Scalings with respect to the plasma collisionality suggest that the confinement will be good enough for an ITER scenario at 17 MA with a power amplification factor (Q) of 10 and might be marginally good enough for a Q = 10 scenario at 15 MA. Those extrapolations are supported by simulations with an integrated core/edge model COREDIV. In addition the hybrid scenario with type-III edge localized modes has been proven to have improved edge conditions without any modification of the central plasma current profile, indicatingcentral plasma current profile, indicating it is compatible with a high beta operation for a steady-state ITER Q = 5 scenario.

251

Determination of the immunoreactive fraction of radiolabeled monoclonal antibodies by linear extrapolation to binding at infinite antigen excess  

International Nuclear Information System (INIS)

Conjugates of monoclonal antibodies with radioactive isotopes, drugs or toxins have great potential for specific radiolocalization and inactivation of tumor cells. Because the conjugation procedure may adversely alter the antibody, quality control procedures must be applied to determine important characteristics of the conjugated antibody. One such property is how much of the conjugated antibody is able to bind to the relevant antigen. Based on theoretical considerations, we have developed a binding assay for radiolabeled monoclonal antibodies in which the fraction of immunoreactive antibody is determined by linear extrapolation to conditions representing infinite antigen excess. This ensures that the true value of the immunoreactive fraction is obtained, as opposed to the apparent immunoreactive fraction determined under conditions of limited antigen excess. The described assay is based on a double-inverse plot of the binding data which may be considered a modification of the Lineweaver-Burk plot. We established the method using 125I- and 111In-labeling of the 2 monoclonal antibodies T101 and 9.2.27 which currently are undergoing radioimaging trials at the National Cancer Institute. For properly performed conjugation procedures, immunoreactive fractions of about 0.9 were obtained, but a prolonged chloramine-T reaction for 125I-labeling resulted in an immunoreactive fraction of only 0.6. Due to its principle of determining binding at i its principle of determining binding at infinite antigen excess, the present method is quite insensitive to variation in the actual amounts of cells and antibody used, as well as the incubation time. (Auth.)

252

Accelerating Monte Carlo molecular simulations by reweighting and reconstructing Markov chains: Extrapolation of canonical ensemble averages and second derivatives to different temperature and density conditions  

Science.gov (United States)

Accurate determination of thermodynamic properties of petroleum reservoir fluids is of great interest to many applications, especially in petroleum engineering and chemical engineering. Molecular simulation has many appealing features, especially its requirement of fewer tuned parameters but yet better predicting capability; however it is well known that molecular simulation is very CPU expensive, as compared to equation of state approaches. We have recently introduced an efficient thermodynamically consistent technique to regenerate rapidly Monte Carlo Markov Chains (MCMCs) at different thermodynamic conditions from the existing data points that have been pre-computed with expensive classical simulation. This technique can speed up the simulation more than a million times, making the regenerated molecular simulation almost as fast as equation of state approaches. In this paper, this technique is first briefly reviewed and then numerically investigated in its capability of predicting ensemble averages of primary quantities at different neighboring thermodynamic conditions to the original simulated MCMCs. Moreover, this extrapolation technique is extended to predict second derivative properties (e.g. heat capacity and fluid compressibility). The method works by reweighting and reconstructing generated MCMCs in canonical ensemble for Lennard-Jones particles. In this paper, system's potential energy, pressure, isochoric heat capacity and isothermal compressibility along isochors, isotherms and paths of changing temperature and density from the original simulated points were extrapolated. Finally, an optimized set of Lennard-Jones parameters (?, ?) for single site models were proposed for methane, nitrogen and carbon monoxide.

Kadoura, Ahmad; Sun, Shuyu; Salama, Amgad

2014-08-01

253

[Role of extrapolation and dynamic stereotype in the mechanisms of the formation and improvement of adequate motor coordinations].  

Science.gov (United States)

Hardness (tonus), viscosity, bioelectric potentials, force and endurance of human muscles were studied. All these properties are subject to considerable alterations in conditions of fluctuations of muscle temperature, oxygen provision. They change permanently also in the process of dynamic work or static efforts (25, 50 and 75% of maximal strength). This is not in accordance with the mechanism of dynamic stereotype. The latter is conformed only to the succession of phases during standard movement performance. The intrinsic structure of motor activity, corresponding to the complex of active motor units, is permanently altered not only during work but in the restitution period as well. The nervous system due to its plasticity, has a high extrapolation capacity. It reacts adequately to new tasks arising with changes in the external or internal environment. Training improves extrapolation but after its cessation extrapolation becomes worse. PMID:7117616

Zimkin, N V

1982-07-01

254

Radon in houses and lung cancer risks. Finnish patient medical research rejects linear extrapolation of mining data  

International Nuclear Information System (INIS)

Epidemiological surveys can play an important role in answering the question whether the risk of lung cancer by radon exposure in houses can be estimated on the basis of linear extrapolation of miner data or not. Recently, some of those surveys have been evaluated. It was concluded that linear extrapolation is subject to great doubts. A reliable epidemiological survey was carried out by means of a Finnish cohort of lung cancer patients and controls, who lived in the same house for at least 18 years. For one year radon concentrations were measured in their houses. The odds ratio (comparable to relative risk) for long cancer was 1.01 per 100 Bq·m-3, which value is significantly different from the value of 1.15, calculated on the basis of linear extrapolation of miner data. 3 tabs., 18 refs

255

Extrapolated experimental critical parameters of unreflected and steel-reflected massive enriched uranium metal spherical and hemispherical assemblies  

International Nuclear Information System (INIS)

Sixty-nine critical configurations of up to 186 kg of uranium are reported from very early experiments (1960s) performed at the Rocky Flats Critical Mass Laboratory near Denver, Colorado. Enriched (93%) uranium metal spherical and hemispherical configurations were studied. All were thick-walled shells except for two solid hemispheres. Experiments were essentially unreflected; or they included central and/or external regions of mild steel. No liquids were involved. Critical parameters are derived from extrapolations beyond subcritical data. Extrapolations, rather than more precise interpolations between slightly supercritical and slightly subcritical configurations, were necessary because experiments involved manually assembled configurations. Many extrapolations were quite long; but the general lack of curvature in the subcritical region lends credibility to their validity. In addition to delayed critical parameters, a procedure is offered which might permit the determination of prompt critical parameters as well for the same cases. This conjectured procedure is not based on any strong physical arguments

256

Comparison of various state equations for approximation and extrapolation of experimental hydrogen molar volumes in wide temperature and pressure intervals  

International Nuclear Information System (INIS)

The numerical analysis of practically all existing formulae such as expansion series, Tait, logarithm, Van der Waals and virial equations for interpolation of experimental molar volumes versus high pressure was carried out. One can conclude that extrapolating dependences of molar volumes versus pressure and temperature can be valid. It was shown that virial equations can be used for fitting experimental data at relatively low pressures P<3 kbar too in distinction to other equations. Direct solving of a linear equation of the third order relatively to volume using extrapolated virial coefficients allows us to obtain good agreement between existing experimental data for high pressure and calculated values

257

Dosimetric adjustments for interspecies extrapolation of inhaled poorly soluble particles (PSP).  

Science.gov (United States)

Direct calculation of delivered dose in the species of interest potentially affects the magnitude of an uncertainty factor needed to address extrapolation of laboratory animal data to equivalent human exposure scenarios, thereby improving the accuracy of human health risk estimates. Development of an inhalation reference concentration (RfC) typically involves extrapolation of an effect level observed in a laboratory animal exposure study to a level of exposure in humans that is not expected to result in an appreciable health risk. The default dose metric used for respiratory effects is the average deposited dose normalized by regional surface area. However, the most relevant dose metric is generally one that is most closely associated with the mode of action leading to the response. Critical factors in determining the best dose metric to characterize the dose-response relationship include the following: the nature of the biological response being examined; the magnitude, duration, and frequency of the intended exposure scenario; and the mechanisms by which the toxicants exert their effects. Dosimetry models provide mechanistic descriptions of these critical factors and can compute species-specific dose metrics. In this article, various dose metrics are postulated based on potential modes of action for poorly soluble particles (PSP). Dosimetry models are used to extrapolate the internal dose metric across species and to estimate the human equivalent concentration (HEC). Dosimetry models for the lower respiratory tract (LRT) of humans and rats are used to calculate deposition and retention using the principle of particle mass balance in the lower respiratory tract. Realistic asymmetric lung geometries using detailed morphometric measurements of the tracheobronchial (TB) airways in rats and humans are employed in model calculations. Various dose metrics are considered for the TB and pulmonary (P) regions. Because time is an explicit parameter incorporated in species-specific constants such as mucociliary clearance rates used in the models, the impact of the application of optimal model structures to refine adjustments and assumptions used in default risk assessment approaches to address exposure duration are discussed. HEC estimates were found for particles ranging in sizes that corresponded to existing toxicity studies of PSP (0.3 to 5 microm). A dose metric expressed as number of particles per biologically motivated normalization factors (e.g., number of ventilatory units, number of alveoli, and number of macrophages) was lower than the current default of mass normalized to regional surface area for either deposited or retained dose estimates. Retained dose estimates were lower than deposited dose estimates across all particle sizes evaluated. Dose metrics based on the deposited mass per unit area in small and large airways of the TB region indicate HECs of 1 to 5 times those of rats: that is, an equivalent exposure to humans which would achieve the same internal dose as in the rat would be 1 to 5 times greater. HEC estimates in the TB region increase with an increase in particle size for particles from 0.3 to 2 microm in the small airways and >3 microm in the large airways. The HEC decreases with increase in particle size in the P region across all particle sizes studied, and the decrease has a more significant slope for those particles >2 microm due to the limited inhalability of particles this size in rats relative to humans. Our modeling results elucidate a number of important issues to be considered in assessing current default approaches to dosimetry adjustment for inhaled PSP. Simulation of realistic, polydisperse particle distributions for the human exposure scenario results in reduced HEC estimates compared to estimates derived with the experimental particle distribution used in the laboratory animal study. Consideration should be given also to replacing the default dose metric of normalized deposited dose in the P region wit

Jarabek, Annie M; Asgharian, Bahman; Miller, Frederick J

2005-01-01

258

Beagle: an appropriate experimental animal for extrapolating the organ distribution pattern of Th in humans  

International Nuclear Information System (INIS)

The concentrations and the organ distribution patterns of 228Th, 230Th and 232Th in two 9-y-old dogs of our beagle colony were determined. The dogs were exposed only to background environmental levels of Th isotopes through ingestion (food and water) and inhalation as are humans. The organ distribution patterns of the isotopes in the beagles were compared to the organ distribution patterns in humans to determine if it is appropriate to extrapolate the beagle organ burden data to humans. Among soft tissues, only the lungs, lymph nodes, kidney and liver, and skeleton contained measurable amounts of Th isotopes. The organ distribution pattern of Th isotopes in humans and dog are similar, the majority of Th being in the skeleton of both species. The average skeletal concentrations of 228Th in dogs were 30 to 40 times higher than the average skeletal concentrations of the parent 232Th, whereas the concentration of 228Th in human skeleton was only four to five times higher than 232Th. This suggests that dogs have a higher intake of 228Ra through food than humans. There is a similar trend in the accumulations of 232Th, 230Th and 228Th in the lungs of dog and humans. The percentages of 232Th, 230Th and 228Th in human lungs are 26, 9.7 and 4.8, respectively, compared to 4.2, 2.6 and 0.48, respectively, in dog lungs. The larger percentages of Th isotopes in human lungs may be due simply to the longer life span of humans. If the burdens of Th isotopes in human lungs are normalizof Th isotopes in human lungs are normalized to an exposure time of 9.2 y (mean age of dogs at the time of sacrifice), the percent burden of 232Th, 230Th and 228Th in human lungs are estimated to be 3.6, 1.3 and 0.66, respectively. These results suggest that the beagle may be an appropriate experimental animal for extrapolating the organ distribution pattern of Th in humans

259

Multiple time step molecular dynamics in the optimized isokinetic ensemble steered with the molecular theory of solvation: Accelerating with advanced extrapolation of effective solvation forces  

Energy Technology Data Exchange (ETDEWEB)

We develop efficient handling of solvation forces in the multiscale method of multiple time step molecular dynamics (MTS-MD) of a biomolecule steered by the solvation free energy (effective solvation forces) obtained from the 3D-RISM-KH molecular theory of solvation (three-dimensional reference interaction site model complemented with the Kovalenko-Hirata closure approximation). To reduce the computational expenses, we calculate the effective solvation forces acting on the biomolecule by using advanced solvation force extrapolation (ASFE) at inner time steps while converging the 3D-RISM-KH integral equations only at large outer time steps. The idea of ASFE consists in developing a discrete non-Eckart rotational transformation of atomic coordinates that minimizes the distances between the atomic positions of the biomolecule at different time moments. The effective solvation forces for the biomolecule in a current conformation at an inner time step are then extrapolated in the transformed subspace of those at outer time steps by using a modified least square fit approach applied to a relatively small number of the best force-coordinate pairs. The latter are selected from an extended set collecting the effective solvation forces obtained from 3D-RISM-KH at outer time steps over a broad time interval. The MTS-MD integration with effective solvation forces obtained by converging 3D-RISM-KH at outer time steps and applying ASFE at inner time steps is stabilized by employing the optimized isokinetic Nosé-Hoover chain (OIN) ensemble. Compared to the previous extrapolation schemes used in combination with the Langevin thermostat, the ASFE approach substantially improves the accuracy of evaluation of effective solvation forces and in combination with the OIN thermostat enables a dramatic increase of outer time steps. We demonstrate on a fully flexible model of alanine dipeptide in aqueous solution that the MTS-MD/OIN/ASFE/3D-RISM-KH multiscale method of molecular dynamics steered by effective solvation forces allows huge outer time steps up to tens of picoseconds without affecting the equilibrium and conformational properties, and thus provides a 100- to 500-fold effective speedup in comparison to conventional MD with explicit solvent. With the statistical-mechanical 3D-RISM-KH account for effective solvation forces, the method provides efficient sampling of biomolecular processes with slow and/or rare solvation events such as conformational transitions of hydrated alanine dipeptide with the mean life times ranging from 30 ps up to 10 ns for “flip-flop” conformations, and is particularly beneficial for biomolecular systems with exchange and localization of solvent and ions, ligand binding, and molecular recognition.

Omelyan, Igor, E-mail: omelyan@ualberta.ca, E-mail: omelyan@icmp.lviv.ua [National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9 (Canada); Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2G8 (Canada); Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, 1 Svientsitskii Street, Lviv 79011 (Ukraine); Kovalenko, Andriy, E-mail: andriy.kovalenko@nrc-cnrc.gc.ca [National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9 (Canada); Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2G8 (Canada)

2013-12-28

260

Multiple time step molecular dynamics in the optimized isokinetic ensemble steered with the molecular theory of solvation: Accelerating with advanced extrapolation of effective solvation forces  

International Nuclear Information System (INIS)

We develop efficient handling of solvation forces in the multiscale method of multiple time step molecular dynamics (MTS-MD) of a biomolecule steered by the solvation free energy (effective solvation forces) obtained from the 3D-RISM-KH molecular theory of solvation (three-dimensional reference interaction site model complemented with the Kovalenko-Hirata closure approximation). To reduce the computational expenses, we calculate the effective solvation forces acting on the biomolecule by using advanced solvation force extrapolation (ASFE) at inner time steps while converging the 3D-RISM-KH integral equations only at large outer time steps. The idea of ASFE consists in developing a discrete non-Eckart rotational transformation of atomic coordinates that minimizes the distances between the atomic positions of the biomolecule at different time moments. The effective solvation forces for the biomolecule in a current conformation at an inner time step are then extrapolated in the transformed subspace of those at outer time steps by using a modified least square fit approach applied to a relatively small number of the best force-coordinate pairs. The latter are selected from an extended set collecting the effective solvation forces obtained from 3D-RISM-KH at outer time steps over a broad time interval. The MTS-MD integration with effective solvation forces obtained by converging 3D-RISM-KH at outer time steps and applying ASFE at inner time steps is stabilized by employing the optimized isokinetic Nosé-Hoover chain (OIN) ensemble. Compared to the previous extrapolation schemes used in combination with the Langevin thermostat, the ASFE approach substantially improves the accuracy of evaluation of effective solvation forces and in combination with the OIN thermostat enables a dramatic increase of outer time steps. We demonstrate on a fully flexible model of alanine dipeptide in aqueous solution that the MTS-MD/OIN/ASFE/3D-RISM-KH multiscale method of molecular dynamics steered by effective solvation forces allows huge outer time steps up to tens of picoseconds without affecting the equilibrium and conformational properties, and thus provides a 100- to 500-fold effective speedup in comparison to conventional MD with explicit solvent. With the statistical-mechanical 3D-RISM-KH account for effective solvation forces, the method provides efficient sampling of biomolecular processes with slow and/or rare solvation events such as conformational transitions of hydrated alanine dipeptide with the mean life times ranging from 30 ps up to 10 ns for “flip-flop” conformations, and is particularly beneficial for biomolecular systems with exchange and localization of solvent and ions, ligand binding, and molecular recognition

 
 
 
 
261

Characterization and application of two extrapolation chambers in standard X radiation beams; Caracterizacao e aplicacao de duas camaras de extrapolacao em feixes padronizados de radiacao X  

Energy Technology Data Exchange (ETDEWEB)

The extrapolation chambers are ionization chambers with variable volume, and they are mainly utilized as beta radiation detectors. In this work two extrapolation chambers were characterized, a commercial PTW extrapolation chamber and another extrapolation chamber developed at the Calibration Laboratory of IPEN, for application as reference systems in mammography, conventional diagnostic radiology and radiotherapy beams. The results obtained from the characterization tests of the chamber response: leakage current, short- and medium terms stability, determination of the saturation currents and the ion collection efficiencies, angular and energy dependence, show that these extrapolation chambers may be utilized for low-energy X radiation beam dosimetry. The transmission factors in tissue and the calibration factors were also determined for all cited radiation qualities. Finally, a procedure was established for calibration of radiation detectors in standard X radiation beams, using the extrapolation chambers. (author)

Silva, Eric Alexandre Brito da

2011-07-01

262

Root crack sizing using phased array inspections and autoregressive spectral extrapolation signal processing  

Science.gov (United States)

Phased array inspection was conducted on a V-butt welded steel sample with multiple shallow flaws of varying depths. The inspection measurements were processed using Wiener filtering and Autoregressive Spectral Extrapolation (AS) to enhance the signals. Phased array inspections were conducted using multiple phased array probes of varying nominal central frequencies (2.25, 4, 5 and 10 MHz). This paper describes the measured results, which show high accuracy, typically in the range of 0.1-0.2 mm. The results concluded that: 1. There was no statistical difference between the calculated flaw depths from phased array inspections at different flaw tip angles. 2. There was no statistical difference in flaw depths calculated using phased array data collected from either side of the weld. 3. Flaws with depths less than the estimated probe signal shear wavelength could not be sized. 4. Finally, there was no statistical difference in the calculated flaw depths using phased array probes with different sampling frequencies and destructive measurements of the flaws.

Caldwell, J.; Shakibi, B.; Moles, M.; Sinclair, A. N.

2013-01-01

263

Demonstration of biosimilarity, extrapolation of indications and other challenges related to biosimilars in europe.  

Science.gov (United States)

The regulatory framework for biosimilars was established across Europe in 2005 based on the concept of biosimilarity. This legislation secures the manufacturing, evaluation, and market authorization (MA) of high-quality safe and efficacious biopharmaceuticals that are highly similar to their reference medicinal product (biosimilars). Demonstration of biosimilarity is documented by full-scale comparability exercises between the biosimilar and the reference product at quality, preclinical, and clinical level. However, the complexity, diversity, and heterogeneity of biosimilars, both in structure and manufacturing, combined with the scientific knowledge accumulated in biotechnological analysis of recombinant therapeutic proteins requires continuous improvement of the regulatory framework based on the evolution and experience gained in this field. This current opinion article presents the concept of biosimilarity, discusses the extrapolation of indications that is acceptable based on a case-by-case basis by CHMP/EMA and uncovers other challenges lying ahead in the development of biosimilars. Biosimilars are still quite 'young' products that require worldwide attention. PMID:25391420

Tsiftsoglou, Asterios S; Trouvin, Jean Hugues; Calvo, Gonzalo; Ruiz, Sol

2014-12-01

264

Evidence for Solar Tether-cutting Magnetic Reconnection from Coronal Field Extrapolations  

CERN Document Server

Magnetic reconnection is one of the primary mechanisms for triggering solar eruptive events, but direct observation of its rapid process has been of challenge. In this Letter we present, using a nonlinear force-free field (NLFFF) extrapolation technique, a visualization of field line connectivity changes resulting from tether-cutting reconnection over about 30 minutes during the 2011 February 13 M6.6 flare in NOAA AR 11158. Evidence for the tether-cutting reconnection was first collected through multiwavelength observations and then by the analysis of the field lines traced from positions of four conspicuous flare 1700 A footpoints observed at the event onset. Right before the flare, the four footpoints are located very close to the regions of local maxima of magnetic twist index. Especially, the field lines from the inner two footpoints form two strongly twisted flux bundles (up to ~1.2 turns), which shear past each other and reach out close to the outer two footpoints, respectively. Immediately after the fl...

Liu, Chang; Lee, Jeongwoo; Wiegelmann, Thomas; Moore, Ronald L; Wang, Haimin

2013-01-01

265

Spatial extrapolation of light use efficiency model parameters to predict gross primary production  

Directory of Open Access Journals (Sweden)

Full Text Available To capture the spatial and temporal variability of the gross primary production as a key component of the global carbon cycle, the light use efficiency modeling approach in combination with remote sensing data has shown to be well suited. Typically, the model parameters, such as the maximum light use efficiency, are either set to a universal constant or to land class dependent values stored in look-up tables. In this study, we employ the machine learning technique support vector regression to explicitly relate the model parameters of a light use efficiency model calibrated at several FLUXNET sites to site-specific characteristics obtained by meteorological measurements, ecological estimations and remote sensing data. A feature selection algorithm extracts the relevant site characteristics in a cross-validation, and leads to an individual set of characteristic attributes for each parameter. With this set of attributes, the model parameters can be estimated at sites where a parameter calibration is not possible due to the absence of eddy covariance flux measurement data. This will finally allow a spatially continuous model application. The performance of the spatial extrapolation scheme is evaluated with a cross-validation approach, which shows the methodology to be well suited to recapture the variability of gross primary production across the study sites.

Karsten Schulz

2011-12-01

266

Extrapolated renormalization group calculation of the surface tension in square-lattice Ising model  

International Nuclear Information System (INIS)

By using self-dual clusters (whose sizes are characterized by the numbers b=2, 3, 4, 5) within a real space renormalization group framework, the longitudinal surface tension of the square-lattice first-neighbour 1/2-spin ferromagnetic Ising model is calculated. The exact critical temperature T sub(c) is recovered for any value of b; the exact assymptotic behaviour of the surface tension in the limit of low temperatures is analytically recovered; the approximate correlation length critical exponents monotonically tend towards the exact value ?=1 (which, at two dimensions, coincides with the surface tension critical exponent ?) for increasingly large cells; the same behaviour is remarked in what concerns the approximate values for the surface tension amplitude in the limit T?T sub(c). Four different numerical procedures are developed for extrapolating to b?infinite the renormalization group results for the surface tension, and quite satisfactory agreement is obtained with Onsager's exact expression (error varying from zero to a few percent on the whole temperature domain). Furthermore the set of RG surface tensions is compared with a set of biased surface tensions (associated to appropriate misfit seams), and find only fortuitous coincidence among them. (Author)

267

Extrapolation of experimental data on late effects of low-dose radionuclides in man  

International Nuclear Information System (INIS)

The situation of living of population on radionuclide contamination areas was simulated in the experimental study using white strainless rats of different ages. The significance of age for late stochastic effects of internal radionuclide contamination with low doses of 131I, 137Cs, 144Ce and 106Ru was studied. Some common regularities and differences in late effects formation depending on age were found. Results of the study showed that the number of tumors developed increased in groups of animals exposed at the youngest age. The younger animal at the moment of internal radionuclide contamination, the higher percentage of malignant tumors appeared. It was especially so for tumors of endocrine glands (pituitary, suprarenal,- and thyroid). Differences in late effects formation related to different type of radionuclide distribution within the body were estimated. On the base of extrapolation the conclusion was made that human organism being exposed at early postnatal or pubertal period could be the most radiosensitive (1.5-2.0 or sometimes even 3-5 times higher than adults). Data confirmed the opinion that children are the most critical part of population even in case of low dose radiation exposure. (author)

268

DEVELOPMENT OF A HYDROGEN ISOTOPE EXTRAPOLATION CURVE FOR PLATINUM CATYLIZED ZEOLITE  

Energy Technology Data Exchange (ETDEWEB)

Experiments were conducted in 2003 and 2004 with protium and deuterium to demonstrate the hydrogen exchange properties of various catalyzed zeolites for tritium stripping purposes. A column was loaded with the experimental material and purged with either H{sub 2} or D{sub 2} as shown in Figure 1 and the effluent monitored with a Prisma Quadrupole. The purge gas was switched when the column outlet concentrations reached >95% of the purge isotope. Outlet concentrations were calculated as the sum of the purge isotope in the elemental form plus the purge isotope in the oxide form (the purge stream was humidified as it passed through the column) divided by the total hydrogen isotopes in the effluent. 1.5 wt.% Pt on CBV 780 zeolite, manufactured by Zeolist International, had the best exchange characteristics, high capacity and fast kinetics, of the materials tested. This memorandum describes an approach to extrapolate previously unpublished hydrogen for deuterium exchange data collected earlier on 1.5 wt.% Pt on CBV 780 to lower concentrations for potential engineering applications.

Staack, G.

2010-07-07

269

Extrapolation of stress rupture data on 9 to 12% Cr steels  

International Nuclear Information System (INIS)

In this document the stress rupture strengths at times of up to 300 000h have been evaluated. In relation to the stress rupture strength, data from four steels, namely 9Cr1Mo, 9Cr2MoNbV, 9Cr1MoVNb and 12CrMoV, were examined and in each case four different parameters (Larson-Miller, Orr-Sherby-Dorn (original), Orr-Sherby-Dorn (ORNL) and Manson-Haferd) were employed to extrapolate the data out to 300 000h. At temperatures relevant to steam generators (c. 500OC) there was found to be little difference in predicted long-term strength values using the four approaches. However, the lower 95% confidence limits have been evaluated and it was found that for some of the steels these were different to the often assumed minimum set at 80% of the average. The rupture ductility values have been statistically evaluated at specific temperatures to establish the trend in ductility with increasing rupture time

270

A physiologically based pharmacokinetic model for quinoxaline-2-carboxylic acid in rats, extrapolation to pigs.  

Science.gov (United States)

A multi-compartment physiologically based pharmacokinetic (PBPK) model to describe the disposition of cyadox (CYX) and its metabolite quinoxaline-2-carboxylic acid (QCA) after a single oral administration was developed in rats (200 mg/kg b.w. of CYX). Considering interspecies differences in physiology and physiochemistry, the model efficiency was validated by pharmacokinetic data set in swine. The model included six compartments that were blood, muscle, liver, kidney, adipose, and a combined compartment for the rest of tissues. The model was parameterized using rat plasma and tissue concentration data that were generated from this study. Model simulations were achieved using a commercially available software program (ACSLXL ibero version 3.0.2.1). Results supported the validity of the model with simulated tissue concentrations within the range of the observations. The correlation coefficients of the predicted and experimentally determined values for plasma, liver, kidney, adipose, and muscles in rats were 0.98, 0.98, 0.98, 0.99, and 0.95, respectively. The rat model parameters were then extrapolated to pigs to estimate QCA disposition in tissues and validated by tissue concentration of QCA in swine. The correlation coefficients between the predicted and observed values were over 0.90. This model could provide a foundation for developing more reliable pig models once more data are available. PMID:25378053

Yang, X; Zhou, Y-F; Yu, Y; Zhao, D-H; Shi, W; Fang, B-H; Liu, Y-H

2015-02-01

271

Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS  

CERN Document Server

We present predicted full-sky maps of submillimeter and microwave emission from the diffuse interstellar dust in the Galaxy. These maps are extrapolated from the 100 micron emission and 100/240 micron flux ratio maps that Schlegel, Finkbeiner, & Davis (1998; SFD98) generated from IRAS and COBE/DIRBE data. Results are presented for a number of physically plausible emissivity models. We find that no power law emissivity function fits the FIRAS data from 200 - 2100 GHz. In this paper we provide a formalism for a multi-component model for the dust emission. A two-component model with a mixture of silicate and carbon-dominated grains (motivated by Pollack et al., 1994}) provides a fit to an accuracy of about 15% to all the FIRAS data over the entire high-latitude sky. Small systematic differences are found between the atomic and molecular phases of the ISM. Our predictions for the thermal (vibrational) emission from Galactic dust at made at the DIRBE resolution of 40' or at the higher resolution of 6.1 arcmin ...

Finkbeiner, D; Schlegel, D J; Finkbeiner, Douglas P.; Davis, Marc; Schlegel, David J.

1999-01-01

272

Effect of mock-up size on extrapolation accuracy in predicting the neutronics parameters of large LMFBRs  

International Nuclear Information System (INIS)

The possible accuracy in neutronics parameter extrapolation for a 1000-MW(e) LMFBR (9500-litre core) was evaluated by performing numerical experiments - on the assumption that the experiments were performed on a smaller mock-up (2000 or 5000 litre) core. The calculated results, obtained by using JAERI-FAST 2 library set, are assumed to be ''experimental value'' (E) and those obtained by 10 different macroscopic group constants, constructed by reaction-wise cross-section uncertainties and normal random numbers, are regarded as ''calculated value'' (C). The neutronics parameters for a 9500-litre core are predicted by using bias factors obtained in 2000- or 5000-litre core assemblies. Then, the extrapolation errors are evaluated. The main results are as follows: If a mock-up experiment is performed on a 2000-litre core, the extrapolation errors will be about 0.6% for ksub(eff), 5% for control-rod worth, and 10% for fission-rate distribution at 90% confidence level. If experiments are performed on a 5000-litre core, those values will be reduced to about 0.2, 3 and 5%, respectively. The benefit obtained by increasing the mock-up system size is very conspicuous for reaction-rate distribution. The above errors are concerned with the error associated with extrapolation from an assumed mock-up system to the objective system, in which both assemblies have similar core composition and configuration. Errors due to unsuitable extrapolation of bias factors to a different core condi of bias factors to a different core condition must be taken into account in addition to the above values. (author)

273

Extrapolation of short term observations to time periods relevant to the isolation of long lived radioactive waste. Results of a co-ordinated research project 1995-2000  

International Nuclear Information System (INIS)

This report addresses safety analysis of the whole repository life-cycle that may require long term performance assessment of its components and evaluation of potential impacts of the facility on the environment. Generic consideration of procedures for the development of predictive tools are completed by detailed characterization of selected principles and methods that were applied and presented within the co-ordinated research project (CRP). The project focused on different approaches to extrapolation, considering radionuclide migration/sorption, physical, geochemical and geotechnical characteristics of engineered barriers, irradiated rock and backfill performance, and on corrosion of metallic and vitreous materials. This document contains a comprehensive discussion of the overall problem and the practical results of the individual projects preformed within the CRP. Each of the papers on the individual projects has been indexed separately

274

Extrapolated ranges and stopping cross-sections for alpha particles (0.4 - 5.5 MeV) in normal and cyclo-hydrocarbons  

International Nuclear Information System (INIS)

The stopping power and ranges of methane, ethane, ethene, n-propane, cyclopropane, n-butane, n-pentane, cyclopentane, n-hexane and benzene for 241Am alpha particles have been measured by the indirect method in which the residual energy is measured as a function of thickness of absorber traversed. Analytical expressions to allow numerical calculations of extrapolated ranges and the stopping cross-sections of the materials investigated are presented and the results are compared where possible with other published results. The standard error of presented range values is 1-2% and that of stopping cross-sections is 2-4%. This work supports the application of the Bragg rule for single and double bonded hydrocarbons. (author)

275

Deposition of inhaled radionuclides in bronchial airways: Implications for extrapolation modeling  

International Nuclear Information System (INIS)

The laboratory rat has frequently been used as a human surrogate to estimate potential health effects following the inhalation of radioactive aerosol particles. Interspecies differences in biological response are commonly related to interspecies differences in particle deposition efficiencies. In addition, the documented site selectivity of bronchial carcinomas suggests that localized particle deposition patterns within bronchial airway bifurcations may have important implications for inhalation risk assessments. Interspecies differences in particle deposition patterns may be related primarily to differences in airway morphometries. Thus the validity of extrapolating rat deposition data to human inhalation conditions depends on their morphometric similarities and differences. It is well known that there are significant structural differences between the human - rather symmetric - and the rat - monopodial - airway systems. In the present approach, we focus on localized deposition patterns and deposition efficiencies in selected asymmetric bronchial airway bifurcations, whose diameters, lengths and branching angles were derived from the stochastic airway models of human and rat lungs (Koblinger and Hofmann, 1985;1988), which are based on the morphometric data of Raabe et al. (1976). The effects of interspecies differences in particle deposition patterns are explored in this study for two asymmetric bifurcation geometries in segmental bronchi and terminal bronchioles of both the human and rat lungs at different particle sizes. In order to examine the effect of flow rate on particle deposition in the human lung, we selected two different minute volumes, i.e., 10 and 60 1 min-1 , which are representative of low and heavy physical activity breathing conditions. In the case of the rat we used a minute volume of 0.234 1 min-1 (Hofmann et al., 1993)

276

Accelerated aging embrittlement of cast duplex stainless steel: Activation energy for extrapolation  

International Nuclear Information System (INIS)

Cast duplex stainless steels, used extensively in LWR systems for primary pressure boundary components such as primary coolant pipes, valves, and pumps, are susceptible to thermal aging embrittlement at reactor operating or higher temperatures. Since a realistic aging embrittlement for end-of-life or life-extension conditions (i.e., 32--50 yr of aging at 280--320 degree C) cannot be produced, it is customary to simulate the metallurgical structure by accelerated aging at ?400 degree C. Over the past several years, extensive data on accelerated aging have been reported from a number of laboratories. The most important information from these studies is the activation energy, namely, the temperature dependence of the aging kinetics between 280 and 400 degree C, which is used to extrapolate the aging characteristics to reactor operating conditions. The activation energies (in the range of 18--50 kcal/mole) are, in general, sensitive to material grade, chemical composition, and fabrication process, and a few empirical correlations, obtained as a function of bulk chemical composition, have been reported. In this paper, a mechanistic understanding of the activation energy is described on the basis of the results of microstructural characterization of various heats of CF-3, -8, and -8M grades that were used in aging studies at different laboratories. The primary mechanism of aging embrittlement at temperatures between 280 and 400 degree C is the spinodal decomposition of the ferrite phase, and M23C6 carbide precipitation on the ferrite/austenite boundaries is the secondary mechanism for high-carbon CF-8 grade. 20 refs., 10 figs., 3 tabs

277

Extrapolation of the relative risk of radiogenic neoplasms across mouse strains and to man  

Energy Technology Data Exchange (ETDEWEB)

We have examined two interrelated questions: is the susceptibility for radiogenic cancer related to the natural incidence, and are the responses of cancer induction by radiation described better by an absolute or a relative risk model. Also, we have examined whether it is possible to extrapolate relative risk estimates across species, from mice to humans. The answers to these questions were obtained from determinations of risk estimates for nine neoplasms in female and male C3Hf/Bd and C57BL/6 Bd mice and from data obtained from previous experiments with female BALB/c Bd and RFM mice. The mice were exposed to /sup 137/Cs gamma rays at 0.4 Gy/min to doses of 0, 0.5, 1.0, or 2.0 Gy. When tumors that were considered the cause of death were examined, both the control and induced mortality rates for the various tumors varied considerably among sexes and strains. The results suggest that in general susceptibility is determined by the control incidence. The relative risk model was significantly superior in five of the tumor types: lung, breast, liver, ovary, and adrenal. Both models appeared to fit myeloid leukemia and Harderian gland tumors, and neither provided good fits for thymic lymphoma and reticulum cell sarcoma. When risk estimates of radiation-induced tumors in humans and mice were compared, it was found that the relative risk estimates for lung, breast, and leukemia were not significantly different between humans and mice. In the case of liver tumors, mice had a higher risk than humans. These results indicate that the relative risk model is the appropriate approach for risk estimation for a number of tumors. The apparent concordance of relative risk estimates between humans and mice for the small number of cancers examined encourages us to undertake further studies.

Storer, J.B.; Mitchell, T.J.; Fry, R.J.

1988-05-01

278

Extrapolation of the relative risk of radiogenic neoplasms across mouse strains and to man.  

Science.gov (United States)

We have examined two interrelated questions: is the susceptibility for radiogenic cancer related to the natural incidence, and are the responses of cancer induction by radiation described better by an absolute or a relative risk model. Also, we have examined whether it is possible to extrapolate relative risk estimates across species, from mice to humans. The answers to these questions were obtained from determinations of risk estimates for nine neoplasms in female and male C3Hf/Bd and C57BL/6 Bd mice and from data obtained from previous experiments with female BALB/c Bd and RFM mice. The mice were exposed to 137Cs gamma rays at 0.4 Gy/min to doses of 0, 0.5, 1.0, or 2.0 Gy. When tumors that were considered the cause of death were examined, both the control and induced mortality rates for the various tumors varied considerably among sexes and strains. The results suggest that in general susceptibility is determined by the control incidence. The relative risk model was significantly superior in five of the tumor types: lung, breast, liver, ovary, and adrenal. Both models appeared to fit myeloid leukemia and Harderian gland tumors, and neither provided good fits for thymic lymphoma and reticulum cell sarcoma. When risk estimates of radiation-induced tumors in humans and mice were compared, it was found that the relative risk estimates for lung, breast, and leukemia were not significantly different between humans and mice. In the case of liver tumors, mice had a higher risk than humans. These results indicate that the relative risk model is the appropriate approach for risk estimation for a number of tumors. The apparent concordance of relative risk estimates between humans and mice for the small number of cancers examined encourages us to undertake further studies. PMID:3375429

Storer, J B; Mitchell, T J; Fry, R J

1988-05-01

279

The cerebellum and visual perceptual learning: evidence from a motion extrapolation task.  

Science.gov (United States)

Visual perceptual learning is widely assumed to reflect plastic changes occurring along the cerebro-cortical visual pathways, including at the earliest stages of processing, though increasing evidence indicates that higher-level brain areas are also involved. Here we addressed the possibility that the cerebellum plays an important role in visual perceptual learning. Within the realm of motor control, the cerebellum supports learning of new skills and recalibration of motor commands when movement execution is consistently perturbed (adaptation). Growing evidence indicates that the cerebellum is also involved in cognition and mediates forms of cognitive learning. Therefore, the obvious question arises whether the cerebellum might play a similar role in learning and adaptation within the perceptual domain. We explored a possible deficit in visual perceptual learning (and adaptation) in patients with cerebellar damage using variants of a novel motion extrapolation, psychophysical paradigm. Compared to their age- and gender-matched controls, patients with focal damage to the posterior (but not the anterior) cerebellum showed strongly diminished learning, in terms of both rate and amount of improvement over time. Consistent with a double-dissociation pattern, patients with focal damage to the anterior cerebellum instead showed more severe clinical motor deficits, indicative of a distinct role of the anterior cerebellum in the motor domain. The collected evidence demonstrates that a pure form of slow-incremental visual perceptual learning is crucially dependent on the intact cerebellum, bearing the notion that the human cerebellum acts as a learning device for motor, cognitive and perceptual functions. We interpret the deficit in terms of an inability to fine-tune predictive models of the incoming flow of visual perceptual input over time. Moreover, our results suggest a strong dissociation between the role of different portions of the cerebellum in motor versus non-motor functions, with only the posterior lobe being responsible for learning in the perceptual domain. PMID:24959702

Deluca, Cristina; Golzar, Ashkan; Santandrea, Elisa; Lo Gerfo, Emanuele; Ešto?inová, Jana; Moretto, Giuseppe; Fiaschi, Antonio; Panzeri, Marta; Mariotti, Caterina; Tinazzi, Michele; Chelazzi, Leonardo

2014-09-01

280

Mangrove litter fall: Extrapolation from traps to a large tropical macrotidal harbour  

Science.gov (United States)

Mangrove litter is a major source of organic matter for detrital food chains in many tropical coastal ecosystems, but scant attention has been paid to the substantial challenges in sampling and extrapolation of rates of litter fall. The challenges arise due to within-stand heterogeneity including incomplete canopy cover, and canopy that is below the high tide mark. We sampled litter monthly for three years at 35 sites across eight mapped communities in the macrotidal Darwin Harbour, northern Australia. Totals were adjusted for mean community canopy cover and the occurrence of canopy below the high tide mark. The mangroves of Darwin Harbour generate an estimated average of 5.0 t ha -1 yr -1 of litter. This amount would have been overestimated by 32% had we not corrected for limited canopy cover and underestimated by 11% had we not corrected for foliage that is below the high tide mark. Had we made neither correction, we would have overestimated litter fall by 17%. Among communities, rates varied 2.6-fold per unit area of canopy, and 3.9-fold among unit area of community. Seaward fringe mangroves were the most productive per unit of canopy area but the canopy was relatively open; Tidal creek forest was the most productive per unit area of community. Litter fall varied 1.1-fold among years and 2.0-fold among months though communities exhibited a range of seasonalities. Our study may be the most extensively stratified and sampled evaluation of mangrove litter fall in a tropical estuary. We believe our study is also the first such assessment to explicitly deal with canopy discontinuities and demonstrates that failure to do so can result in considerable overestimation of mangrove productivity.

Metcalfe, Kristin N.; Franklin, Donald C.; McGuinness, Keith A.

2011-11-01

 
 
 
 
281

Characterization of a extrapolation chamber in standard X-ray beam, radiodiagnosis level; Caracterizacao de uma camara de extrapolacao em feixes padroes de raios X, nivel radiodiagnostico  

Energy Technology Data Exchange (ETDEWEB)

The extrapolation chamber is a ionization chamber used for detection low energy radiation and can be used as an standard instrument for beta radiation beams. This type of ionization chamber have as main characteristic the variation of sensible volume. This paper performs a study of characterization of a PTW commercial extrapolation chamber, in the energy interval of the qualities of conventional radiodiagnostic

Silva, Eric A.B. da; Caldas, Linda V.E., E-mail: ebrito@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-10-26

282

Characteristics of phase angle, extrapolated conductance and ion relaxation time in the low-frequency admittance locus plot of human palmar skin.  

Science.gov (United States)

The Cole-Cole equation can be used to model the electrical admittance of human skin. Using a previously published two-frequency (AC excitation) three-electrode method, the admittance locus plot (ALP) in the low-frequency region (< 1000 Hz) has been shown to be very well approximated by a straight line and can be described with frequency-independent parameters; phase angle alpha pi/2, conductance at extrapolated zero frequency G0 = 1/R0, and ion relaxation time tau. The aim of the paper is to study characteristics of alpha pi/2, G0 and tau in the low-frequency ALP of human palmar skin. The measured data are calculated off-line on a personal computer. Relative changes in alpha pi/2 are small (< 2%) even during a heavy physical-exercise period. G0 corresponds well with GDC obtained by the traditional DC method at excitations up to 200 mV (relative differences < or = 5% during baseline registration). Based on these findings, two comparatively simpler methods using only one lock-in amplifier are suggested: either measuring simultaneously with DC and at one frequency with AC excitation, or measuring at two different frequencies successively. The low-frequency part of the ALP can then be determined. G0, alpha and tau estimated by these simplified methods are in good agreement with the simultaneous two-frequency method and should therefore be suited for clinical applications. PMID:8022212

Qiao, Z G; Mørkrid, L; Vøllestad, N K

1994-03-01

283

Accurate adiabatic potential energy surface for 12A' state of FH2 based on ab initio data extrapolated to the complete basis set limit  

Science.gov (United States)

An accurate single-sheeted double many-body expansion potential energy surface is reported for the title system. It is obtained by using the aug-cc-pVTZ and aug-cc-pVQZ basis sets with extrapolation of the electron correlation energy to the complete basis set limit, plus extrapolation to the complete basis set limit of the complete-active-space self-consistent field energy. The collinear and bending barrier heights of the new global potential energy surface is 2.301 and 1.768 kcal mol-1, in very good agreement with the values of 2.222 and 1.770 kcal mol-1 from the current best potential energy surface. In particular, the new potential energy surface describes well the important van der Waals interactions which is very useful for investigating the dynamics of the title system. Thus, the new potential energy surface can both be recommended for dynamics studies of the F + H2 reaction and as building block for constructing the potential energy surfaces of larger fluorine/hydrogen containing systems. Based on the new potential energy surface, a preliminary theoretical study of the reaction F(2P) + H2 (X1 ?g+) ? FH(X1?+) + H(2S) has been carried out with the methods of quasi-classical trajectory and quantum mechanical. The results have shown that the new PES is suitable for any kind of dynamics studies. Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2014-50445-3

Li, Yong-Qing; Song, Yu-Zhi; Joaquim de Campos Varandas, António

2015-01-01

284

Well logging apparatus and method: synthetic logs and synthetic seismograms with extrapolated reflector dip from log measurements  

International Nuclear Information System (INIS)

A borehole investigating device takes measurements of a subsurface earth formation and provides signals forming sonic, formation density or similar logs of the borehole. Additionally, the investigating device measures the dip of seismic signal reflectors traversed by the borehole and provides corresponding dip signals. A seismic section which may or may not include the borehole is selected, and the log and dip signals are combined with signals defining the location of the seismic section with respect to the borehole, to thereby provide synthetic logs for each of a number of virtual boreholes which coincide with selected virtual and/or actual shotpoints of the seismic section. The synthetic log signals are then combined to form a truly twodimensional synthetic seismogram for the selected seismic section. The synthetically derived signals may be corrected in accordance with a selected geological model of the formation

285

Short-Term Forecasting of Urban Storm Water Runoff in Real-Time using Extrapolated Radar Rainfall Data  

DEFF Research Database (Denmark)

Model based short-term forecasting of urban storm water runoff can be applied in realtime control of drainage systems in order to optimize system capacity during rain and minimize combined sewer overflows, improve wastewater treatment or activate alarms if local flooding is impending. A novel online system, which forecasts flows and water levels in real-time with inputs from extrapolated radar rainfall data, has been developed. The fully distributed urban drainage model includes auto-calibration using online in-sewer measurements which is seen to improve forecast skills significantly. The radar rainfall extrapolation (nowcast) limits the lead time of the system to two hours. In this paper, the model set-up is tested on a small urban catchment for a period of 1.5 years. The 50 largest events are presented.

Thorndahl, SØren Liedtke; Rasmussen, Michael R.

2013-01-01

286

Some new aspects of comparison of cell survival-dose curves (statistical analysis and extrapolation number modification factor)  

International Nuclear Information System (INIS)

The formulae are presented permitting to calculate, by the regression analysis, the values of n, D0, Dsub(q1, D37, D50, etc., and D0MF,Dsub(q)MF, D37MF, D50MF, etc., and their errors. The ratios between different doses and DMF were determined. It seemed expedient to use the variance analysis in determining the linearity of exponential parts of the dose-survival curves in the lg S-D coordinates, and the parallelism between them. Eight variants of changes in the main parameters of the dose-survival curves are discussed. New indices are proposed: the extrapolation number modification factor and the extrapolation number logarithm modification factor; the expedience of using thereof is reasoned

287

[Features of the dynamics of the forebrain EEG of Emys orbicularis during the solving of an extrapolation problem].  

Science.gov (United States)

Sharp EEG changes are recorded in bioelectrical activity of the dorsal cortex and dorsal ventricular edge in marsh tortoises in conditions of free movement during solving of an extrapolation task (a test of elementary reasoning ability). These changes of a pathological character, accompanied by neurotic states, were observed in some animals having correctly solved the task several times in succession (2-5), beginning with the first presentation. Such changes of EEG and behaviour were not found in tortoises that committed errors at first presentations of the task and only gradually learned correct solving. Formation of the adequate behaviour can proceed by two means: on the basis of elementary reasoning ability and learning. Disturbance of adequate behaviour in the experiment with characteristic changes of EEG testifies to a difficult state of the animal during solving of the extrapolation task. PMID:4090728

Semiokhina, A F; Ochinskaia, E I; Rubtsova, N B; Pleskacheva, M G; Krushinski?, L V

1985-01-01

288

Extrapolation of the proton form factor from the space-like region by means of Pade approximations  

International Nuclear Information System (INIS)

Extrapolation of the proton form factor from the space-like region has been carried out by means of Pade approximants. The analysis reveals that the form factor has at least three zeros and no poles on the physical sheet. The pronounced peak in the spectral function has been found at the position of the rho-meson. The most unbiased estimate of the proton electric radius has been obtained: r = 0.80 +- 0.03 fm. (author)

289

Improving in vitro to in vivo extrapolation by incorporating toxicokinetic measurements: A case study of lindane-induced neurotoxicity.  

Science.gov (United States)

Approaches for extrapolating in vitro toxicity testing results for prediction of human in vivo outcomes are needed. The purpose of this case study was to employ in vitro toxicokinetics and PBPK modeling to perform in vitro to in vivo extrapolation (IVIVE) of lindane neurotoxicity. Lindane cell and media concentrations in vitro, together with in vitro concentration-response data for lindane effects on neuronal network firing rates, were compared to in vivo data and model simulations as an exercise in extrapolation for chemical-induced neurotoxicity in rodents and humans. Time- and concentration-dependent lindane dosimetry was determined in primary cultures of rat cortical neurons in vitro using "faux" (without electrodes) microelectrode arrays (MEAs). In vivo data were derived from literature values, and physiologically based pharmacokinetic (PBPK) modeling was used to extrapolate from rat to human. The previously determined EC50 for increased firing rates in primary cultures of cortical neurons was 0.6?g/ml. Media and cell lindane concentrations at the EC50 were 0.4?g/ml and 7.1?g/ml, respectively, and cellular lindane accumulation was time- and concentration-dependent. Rat blood and brain lindane levels during seizures were 1.7-1.9?g/ml and 5-11?g/ml, respectively. Brain lindane levels associated with seizures in rats and those predicted for humans (average=7?g/ml) by PBPK modeling were very similar to in vitro concentrations detected in cortical cells at the EC50 dose. PBPK model predictions matched literature data and timing. These findings indicate that in vitro MEA results are predictive of in vivo responses to lindane and demonstrate a successful modeling approach for IVIVE of rat and human neurotoxicity. PMID:25529470

Croom, Edward L; Shafer, Timothy J; Evans, Marina V; Mundy, William R; Eklund, Chris R; Johnstone, Andrew F M; Mack, Cina M; Pegram, Rex A

2015-02-15

290

Characterization of an extrapolation chamber and radiochromic films for verifying the metrological coherence among beta radiation fields  

International Nuclear Information System (INIS)

The metrological coherence among standard systems is a requirement for assuring the reliability of dosimetric quantities measurements in ionizing radiation field. Scientific and technologic improvements happened in beta radiation metrology with the installment of the new beta secondary standard BSS2 in Brazil and with the adoption of the internationally recommended beta reference radiations. The Dosimeter Calibration Laboratory of the Development Center for Nuclear Technology (LCD/CDTN), in Belo Horizonte, implemented the BSS2 and methodologies are investigated for characterizing the beta radiation fields by determining the field homogeneity, the accuracy and uncertainties in the absorbed dose in air measurements. In this work, a methodology to be used for verifying the metrological coherence among beta radiation fields in standard systems was investigated; an extrapolation chamber and radiochromic films were used and measurements were done in terms of absorbed dose in air. The reliability of both the extrapolation chamber and the radiochromic film was confirmed and their calibrations were done in the LCD/CDTN in 90Sr/90Y, 85Kr and 147Pm beta radiation fields. The angular coefficients of the extrapolation curves were determined with the chamber; the field mapping and homogeneity were obtained from dose profiles and isodose with the radiochromic films. A preliminary comparison between the LCD/CDTN and the Instrument Calibration Laboratory of the Nuclear and Energy Research Institute / Sao Paulo (LCI/IPEN) was carried out. Results with the extrapolation chamber measurements showed in terms of absorbed dose in air rates showed differences between both laboratories up to de -I % e 3%, for 90Sr/90Y, 85Kr and 147Pm beta radiation fields, respectively. Results with the EBT radiochromic films for 0.1, 0.3 and 0.15 Gy absorbed dose in air, for the same beta radiation fields, showed differences up to 3%, -9% and -53%. The beta radiation field mappings with radiochromic films in both BSS2 showed that some of them were not geometrically aligned. (author)

291

Parameter extrapolation to ungauged basins with a hydrological distributed model in a regional framework  

Directory of Open Access Journals (Sweden)

Full Text Available A Regional Water Resources study was performed at basins within and draining to the Basque Country Region (N of Spain, with a total area of approximately 8500 km2. The objective was to obtain daily and monthly long-term discharges in 567 points, most of them ungauged, with basin areas ranging from 0.25 to 1850 km2. In order to extrapolate the calibrations at gauged points to the ungauged ones, a distributed and conceptually based model called TETIS was used. In TETIS the runoff production is modelled using five linked tanks at the each cell with different outflow relationships at each tank, which represents the main hydrological processes as snowmelt, evapotranspiration, overland flow, interflow and base flow. The routing along the channels' network couples its geomorphologic characteristics with the kinematic wave approach. The parameter estimation methodology tries to distinguish between the effective parameter used in the model at the cell scale, and the watershed characteristic estimated from the available information, being the best estimation without losing its physical meaning. The relationship between them can be considered as a correction function or, in its simple form, a correction factor. The correction factor can take into account the model input errors, the temporal and spatial scale effects and the watershed characteristics. Therefore, it is reasonable to assume the correction factor is the same for each parameter to all cells within the watershed. This approach reduces drastically the number of parameter to be calibrated, because only the common correction factors are calibrated instead of parameter maps (number of parameters times the number of cells. In this way, the calibration can be performed using automatic methodologies. In this work, the Shuffled Complex Evolution – University of Arizona, SCE-UA algorithm was used. The available recent year's data was used to calibrate the model in 20 of the most representative flow gauge stations in 18 basins with a Nash-Sutcliffe index higher than 0.6 (10 higher than 0.8. The calibrated correction factors at each basin were similar but not equal. The validation process (in time and space was performed using the remaining data in all flow gauge stations (62, with 42 basins with a Nash-Sutcliffe index higher than 0.5 (25 higher than 0.7. Deficient calibration and validations were always related with flow gauge stations very close to the karstic springs. These results confirmed that it was feasible and efficient to use the SCE-UA algorithm for the automatic calibration of distributed conceptual models and the calibrated model could be used at ungauged basins. Finally, meteorological information from the past 50 years at a daily scale was used to generate a daily discharges series at 567 selected points.

J. J. Vélez

2009-02-01

292

Interferometric synthetic aperture radar deformation data used to interpolate and extrapolate hydraulic head time-series  

Science.gov (United States)

A 2004 court decision established that hydraulic head levels within the confined aquifer system of the San Luis Valley (SLV), Colorado be maintained within the range experienced in the years between 1978 and 2000. The current groundwater flow model for this area is not able to predict hydraulic head accurately in the confined aquifer system due to a dearth of calibration points, i.e., hydraulic head measurements, during the time period of interest. The work presented here investigates the extent to which spatially and temporally dense measurements of deformation from Interferometric Synthetic Aperture Radar (InSAR) data could be used to interpolate and extrapolate temporal and spatial gaps in the hydraulic head dataset by performing a calibration at the well locations. We first predicted the magnitude of the seasonal deformation at the confined aquifer well locations by using aquifer thickness/lithology information from well logs and estimates of the aquifer compressibility from the literature. At 11 well locations the seasonal magnitude of the deformation was sufficiently large so as to be reliably measured with InSAR, given the accepted level of uncertainty of the measurement (~ 5 mm). Previous studies in arid or urban areas have shown that high quality InSAR deformation measurements are often collocated with hydraulic head measurements at monitoring wells, making such a calibration approach relatively straightforward. In contrast, the SLV is an agricultural area where many factors, e.g. crop growth, can seriously degrade the quality of the InSAR data. We used InSAR data from the ERS-1 and ERS-2 satellites, which have a temporal sampling of 35 days and a spatial sampling on the order of 10's of meters, and found that the InSAR data were not of sufficiently high quality at any of the 11 selected well locations. Hence, we used geostatistical techniques to analyze the high quality InSAR deformation data elsewhere in the scene and to estimate the deformation at the selected well locations. At the 11 locations we estimated the compressibility parameter that relates the deformation and the hydraulic head. We found that this calibration was effective at 3 of the well locations where the magnitude of the seasonal deformation was > 3 cm, well above the uncertainty of the InSAR measurement. We then estimated the hydraulic head prior to and within the temporal sampling window of the hydraulic head measurements at the 3 well locations. We found that 59% of the InSAR-predicted hydraulic head values agree with the measured hydraulic head values, within the uncertainty of the data. Given our success in extending the hydraulic head data temporally, the next step in our research is to use InSAR data to interpolate spatially between hydraulic head measurements at field sites where the magnitude of the deformation is large enough to be accurately measured by InSAR.

Reeves, J. A.; Knight, R. J.; Zebker, H. A.; Kitanidis, P. K.; Schreuder, W. A.

2013-12-01

293

The Fuzzy Logic Method for Simpler Forecasting  

Directory of Open Access Journals (Sweden)

Full Text Available Fildes and Makridakis (1998, Makridakis and Hibon (2000, and Fildes (2001 indicate that simple extrapolative forecasting methods that are robust forecast equally as well or better than more complicated methods, i.e. Box-Jenkins and other methods. We study the Direct Set Assignment (DSA extrapolative forecasting method. The DSA method is a non-linear extrapolative forecasting method developed within the Mamdani Development Framework, and designed to mimic the architecture of a fuzzy logic control system. We combine the DSA method Winters' Exponential smoothing. This combination provides the best observed forecast accuracy in seven of nine subcategories of time series, and is the top three in terms of observed accuracy in two subcategories. Hence, fuzzy logic which is the basis of the DSA method often is the best method for forecasting.

Jeffrey E. Jarrett

2011-08-01

294

Robust extrapolation scheme for fast estimation of 3D Ising field partition functions: application to within subject fMRI data  

International Nuclear Information System (INIS)

In this paper, we present a first numerical scheme to estimate Partition Functions (PF) of 3D Ising fields. Our strategy is applied to the context of the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated regions and estimate region-dependent, hemodynamic filters. For any region, a specific binary Markov random field may embody spatial correlation over the hidden states of the voxels by modeling whether they are activated or not. To make this spatial regularization fully adaptive, our approach is first based upon it, classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, file proposed extrapolation method allows its to approximate the PFs associated with the Ising fields defined over the remaining brain regions. In comparison with preexisting approaches, our method is robust; to topological inhomogeneities in the definition of the reference regions. As a result, it strongly alleviates the computational burden and makes spatially adaptive regularization of whole brain fMRI datasets feasible. (authors)

295

Comparison of methods analyzing the uncertainty of thermal hydraulic calculations. UMAE, CSAU, GRS and IPSN methods. Rev. 0  

International Nuclear Information System (INIS)

A description of 4 methods used within the European Union for the determination of the uncertainty of thermal hydraulic analyses is given. The method developed by the University of Pisa (Uncertainty Methods based on Accuracy Extrapolation, UMAE) is based on the extrapolation of results of integral experiments, whereas the probabilistic methods of CSAU, GRS and IPSN are based on a quantification of uncertainties phenomena by range and subjective probability distribution function. (author)

296

Application of physiologically-based toxicokinetic modelling in oral-to-dermal extrapolation of threshold doses of cosmetic ingredients.  

Science.gov (United States)

The application of physiologically based toxicokinetic (PBTK) modelling in route-to-route (RtR) extrapolation of three cosmetic ingredients: coumarin, hydroquinone and caffeine is shown in this study. In particular, the oral no-observed-adverse-effect-level (NOAEL) doses of these chemicals are extrapolated to their corresponding dermal values by comparing the internal concentrations resulting from oral and dermal exposure scenarios. The PBTK model structure has been constructed to give a good simulation performance of biochemical processes within the human body. The model parameters are calibrated based on oral and dermal experimental data for the Caucasian population available in the literature. Particular attention is given to modelling the absorption stage (skin and gastrointestinal tract) in the form of several sub-compartments. This gives better model prediction results when compared to those of a PBTK model with a simpler structure of the absorption barrier. In addition, the role of quantitative structure-property relationships (QSPRs) in predicting skin penetration is evaluated for the three substances with a view to incorporating QSPR-predicted penetration parameters in the PBTK model when experimental values are lacking. Finally, PBTK modelling is used, first to extrapolate oral NOAEL doses derived from rat studies to humans, and then to simulate internal systemic/liver concentrations - Area Under Curve (AUC) and peak concentration - resulting from specified dermal and oral exposure conditions. Based on these simulations, AUC-based dermal thresholds for the three case study compounds are derived and compared with the experimentally obtained oral threshold (NOAEL) values. PMID:24731971

Gajewska, M; Worth, A; Urani, C; Briesen, H; Schramm, K-W

2014-06-16

297

Is the climate right for pleistocene rewilding? Using species distribution models to extrapolate climatic suitability for mammals across continents.  

Science.gov (United States)

Species distribution models (SDMs) are increasingly used for extrapolation, or predicting suitable regions for species under new geographic or temporal scenarios. However, SDM predictions may be prone to errors if species are not at equilibrium with climatic conditions in the current range and if training samples are not representative. Here the controversial "Pleistocene rewilding" proposal was used as a novel example to address some of the challenges of extrapolating modeled species-climate relationships outside of current ranges. Climatic suitability for three proposed proxy species (Asian elephant, African cheetah and African lion) was extrapolated to the American southwest and Great Plains using Maxent, a machine-learning species distribution model. Similar models were fit for Oryx gazella, a species native to Africa that has naturalized in North America, to test model predictions. To overcome biases introduced by contracted modern ranges and limited occurrence data, random pseudo-presence points generated from modern and historical ranges were used for model training. For all species except the oryx, models of climatic suitability fit to training data from historical ranges produced larger areas of predicted suitability in North America than models fit to training data from modern ranges. Four naturalized oryx populations in the American southwest were correctly predicted with a generous model threshold, but none of these locations were predicted with a more stringent threshold. In general, the northern Great Plains had low climatic suitability for all focal species and scenarios considered, while portions of the southern Great Plains and American southwest had low to intermediate suitability for some species in some scenarios. The results suggest that the use of historical, in addition to modern, range information and randomly sampled pseudo-presence points may improve model accuracy. This has implications for modeling range shifts of organisms in response to climate change. PMID:20877563

Richmond, Orien M W; McEntee, Jay P; Hijmans, Robert J; Brashares, Justin S

2010-01-01

298

Verification of electricity savings through energy-efficient train management - Measurements made on trains and extrapolations - Annex 3; Verifizierung der Stromeinsparung durch energieeffizientes Zugsmanagement - Anhang 3: Messungen auf Fahrzeugen und Hochrechnungen  

Energy Technology Data Exchange (ETDEWEB)

This appendix to a final report for the Swiss Federal Office of Energy (SFOE) presents the results of measurements made on trains and presents and discusses extrapolations made on the basis of these measurements. The evaluation and selection of the trains on which the measurements were to be made is discussed. Mainly passenger trains were selected as only few goods engines have the necessary equipment and equipping them would be costly. Measurements made on a Re 460 locomotive are presented and discussed. The methods used in the energy analysis are described and the results obtained on several itineraries that include partial single-track working are presented and discussed.

Meyer, M.; Lerjen, M.; Menth, S. [emkamatik GmbH, Wettingen (Switzerland); Luethi, M. [Swiss Federal Insitute of Technology (ETHZ), Institute for Transport Planning and Systems (IVT), Zuerich (Switzerland); Tuchschmid, M. [SBB AG, BahnUmwelt-Center, 3000 Bern (Switzerland)

2009-11-15

299

Extrapolation of contrail investigations by LIDAR to larger scale measurements. Analysis and calibration of CCD camera and satellite images  

Energy Technology Data Exchange (ETDEWEB)

The CCD image of a persistent contrail and the coincident LIDAR measurement are presented. To extrapolate the LIDAR derived optical thickness to the video field of view an anisotropy correction and calibration has to be performed. Observed bright halo components result from highly regular oriented hexagonal crystals with sizes of 200 {mu}m-2 mm. This explained by measured ambient humidities below the formation threshold of natural cirrus. Optical thickness from LIDAR shows significant discrepancies to the result from coincident NOAA-14 data. Errors result from anisotropy correction and parameterized relations between AVHRR channels and optical properties. (author) 28 refs.

Sussmann, R.; Homburg, F.; Freudenthaler, V.; Jaeger, H. [Frauenhofer Inst. fuer Atmosphaerische Umweltforschung, Garmisch-Partenkirchen (Germany)

1997-12-31

300

Comparison of the San Marco 3 Nace neutral composition data with the extrapolated Ogo 6 empirical model. [Neutral Atmospheric Composition Experiment  

Science.gov (United States)

An investigation is conducted concerning the feasibility to extrapolate the data of the Ogo 6 empirical composition model to altitudes which are lower than 450 km. Extrapolated Ogo 6 model densities are, therefore, compared with data obtained in the Neutral Atmospheric Composition Experiment (Nace) carried out during the time from April to November 1971. The results of the investigation support the conclusions of an earlier comparison of Ogo 6 and Nace data conducted by Newton et al. (1973).

Kasprzak, W. T.; Newton, G. P.

1976-01-01

 
 
 
 
301

Transcript markers of herbicide stress in Arabidopsis and their cross-species extrapolation to Brassica  

Science.gov (United States)

Low concentrations and short environmental persistence times of some herbicides make it difficult to develop analytical methods to detect herbicide residues in plants or soils. In contrast, genomics may provide tools to identify herbicide exposure to plants in field settings. Usi...

302

Turbulent flux modelling with a simple 2-layer soil model and extrapolated surface temperature applied at Nam Co Lake basin on the Tibetan Plateau  

Directory of Open Access Journals (Sweden)

Full Text Available This paper introduces a surface model with two soil-layers for use in a high-resolution circulation model that has been modified with an extrapolated surface temperature, to be used for the calculation of turbulent fluxes. A quadratic temperature profile based on the layer mean and base temperature is assumed in each layer and extended to the surface. The model is tested at two sites on the Tibetan Plateau near Nam Co Lake during four days during the 2009 Monsoon season. In comparison to a two-layer model without explicit surface temperature estimate, there is a greatly reduced delay in diurnal flux cycles and the modelled surface temperature is much closer to observations. Comparison with a SVAT model and eddy covariance measurements shows an overall reasonable model performance based on RMSD and cross correlation comparisons between the modified and original model. A potential limitation of the model is the need for careful initialisation of the initial soil temperature profile, that requires field measurements. We show that the modified model is capable of reproducing fluxes of similar magnitudes and dynamics when compared to more complex methods chosen as a reference.

T. Gerken

2012-04-01

303

Chiral Extrapolations of light resonances from dispersion relations and Chiral Perturbation Theory  

CERN Document Server

We review our recent study of the pion mass dependence of the rho and sigma resonances generated from one-loop SU(2) Chiral Perturbation Theory (ChPT) with the Inverse Amplitude Method (IAM) which was modified to properly account for the Adler zero. The method is based on analyticity, elastic unitarity and ChPT at low energies, thus yielding the pion mass dependence of the resonance pole positions from the ChPT series up to a given order. We find that the rho-pi-pi coupling constant is almost m_pi independent and that our prediction compare well with some recent lattice results for the rho mass. These findings may be relevant for studies of the meson spectrum and form factors on the lattice.

Ríos, Guillermo; Hanhart, Christoph; Peláez, José Ramón

2009-01-01

304

Imaging of defects in girth welds using inverse wave field extrapolation of ultrasonic data:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ultrasonic non-destructive testing is a renowned method for the inspection of girth welds. However, defect sizing and characterization remains challenging with the current inspection philosophy. In addition, data display and interpretation is not straightforward and requires skill and experience from the inspector. A better and more reliable inspection result would contribute to safer pipeline construction and economic benefits (like low false call rates and the possibility to use smaller wal...

Po?rtzgen, N.

2007-01-01

305

Phase shift analysis of ?? system at energies between 500 and 1370 MeV with Chew-Low extrapolation results from reactions ?-p?p?-?0 and ?-p?n?+?- at 3.92 GeV/c  

International Nuclear Information System (INIS)

Experimental data (12 evts/?N???N reactions) were derived from the analysis of 450000 pictures obtained with the 2 meter hydrogen bubble chamber at CERN. The Chew-Low extrapolation method was used to obtain total and differential cross-sections of ?+0?-??+0?- reactions. Pseudo-peripherism hypothesis, in agreement with data at energy less 1 GeV, was modified to take into account the non-vanishing reactions amplitude at t=0, observed above 1 GeV. Several phase shift analyses were done, either with energy parametrisation of phase shifts, or at fixed energy. Main results concern the parameters of S* (Jsup(P)=0+) resonance which come out from a meromorphic parametrisation of the S0 wave amplitude in the region of the KantiK channel threshold (987 MeV) and the dynamical wave structures in the f0 (Jsup(P)=2+) resonance region. The agreement observed between these results and those of main previous experiments is a proof of the usefulness of the extrapolation method above 1 GeV

306

Correlation and extrapolation of creep ductility data for four elevated temperature structural materials  

International Nuclear Information System (INIS)

The amount of deformation that a component can successfully endure without incurring failure-inducing damage can be a useful limit in elevated temperature design. Treatment of experimental creep ductility data by a parametric analysis technique allows the prediction of such limits. Application of such a method to data for various ductility indices for four elevated-temperature structural materials is presented, including a discussion of the results. Materials studied include types 304 and 316 stainless steel, 21/4 Cr-1 Mo steel, and Inconel Alloy 718. (10 tables, 16 figures) (U.S.)

307

Correlation and extrapolation of creep ductility data for four elevated-temperature structural materials  

International Nuclear Information System (INIS)

The amount of deformation that a component can successfully endure without incurring failure-inducing damage can be a useful limit in elevated temperature design. Treatment of experimental creep ductility data by a parametric analysis technique allows the prediction of such limits. Application of such a method to data for various ductility indices for four elevated-temperature structural materials is presented, including a discussion of the results. Materials studied include types 304 and 316 stainless steel, 21/4 Cr-1 Mo steel, and Inconel Alloy 718

308

Inflammatory findings on species extrapolations : humans are definitely no 70-kg mice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Modern toxicology has embraced in vitro methods, and major hopes are based on the Omics technologies and systems biology approaches they bring along (Hartung and McBride in ALTEX 28(2):83–93, 2011; Hartung et al. in ALTEX 29(2):119–28, 2012). A culture of stringent validation has been developed for such approaches (Leist et al. in ALTEX 27(4):309–317, 2010; ALTEX 29(4):373–88, 2012a; Toxicol Res 1:8–22, 2012b), while the quality and usefulness of animal experiments have been little ...

Leist, Marcel; Hartung, Thomas

2013-01-01

309

Inflammatory findings on species extrapolations: humans are definitely no 70-kg mice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Modern toxicology has embraced in vitro methods, and major hopes are based on the Omics technologies and systems biology approaches they bring along (Hartung and McBride in ALTEX 28(2):83–93, 2011; Hartung et al. in ALTEX 29(2):119–28, 2012). A culture of stringent validation has been developed for such approaches (Leist et al. in ALTEX 27(4):309–317, 2010; ALTEX 29(4):373–88, 2012a; Toxicol Res 1:8–22, 2012b), while the quality and usefulness of animal experiments have been little ...

Leist, Marcel; Hartung, Thomas

2013-01-01

310

The efficiency variation method for 4??-? coincidence counting by ink-jet printing  

International Nuclear Information System (INIS)

In order to vary the counting efficiencies in the 4??-? coincidence extrapolation technique, a radioactive source was coated directly with varying amounts of an electrical conducting pigment using an ink-jet printer. This method can be used to efficiently prepare the multiple sources needed to generate efficiency extrapolation curves, and was successfully applied to the standardization of a 54Mn source

311

Transport equation solving methods  

International Nuclear Information System (INIS)

This work is mainly devoted to Csub(N) and Fsub(N) methods. CN method: starting from a lemma stated by Placzek, an equivalence is established between two problems: the first one is defined in a finite medium bounded by a surface S, the second one is defined in the whole space. In the first problem the angular flux on the surface S is shown to be the solution of an integral equation. This equation is solved by Galerkin's method. The Csub(N) method is applied here to one-velocity problems: in plane geometry, slab albedo and transmission with Rayleigh scattering, calculation of the extrapolation length; in cylindrical geometry, albedo and extrapolation length calculation with linear scattering. Fsub(N) method: the basic integral transport equation of the Csub(N) method is integrated on Case's elementary distributions; another integral transport equation is obtained: this equation is solved by a collocation method. The plane problems solved by the Csub(N) method are also solved by the Fsub(N) method. The Fsub(N) method is extended to any polynomial scattering law. Some simple spherical problems are also studied. Chandrasekhar's method, collision probability method, Case's method are presented for comparison with Csub(N) and Fsub(N) methods. This comparison shows the respective advantages of the two methods: a) fast convergence and possible extension to various geometries for Csub(N) method; b) easy calculations and easy extension to polynomial scattering for Fsub(N) method

312

Full-disk nonlinear force-free field extrapolation of SDO/HMI and SOLIS/VSM magnetograms  

CERN Document Server

Extrapolation codes in Cartesian geometry for modelling the magnetic field in the corona do not take the curvature of the Sun's surface into account and can only be applied to relatively small areas, e.g., a single active region. We compare the analysis of the photospheric magnetic field and subsequent force-free modeling based on full-disk vector maps from Helioseismic and Magnetic Imager (HMI) on board solar dynamics observatory (SDO) and Vector Spectromagnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS). We use Helioseismic and Magnetic Imager and Vector Spectromagnetograph photospheric magnetic field measurements to model the force-free coronal field above multiple solar active regions, assuming magnetic forces to dominate. We solve the nonlinear force-free field equations by minimizing a functional in spherical coordinates over a full disk excluding the poles. After searching for the optimum modeling parameters for the particular data sets, we compare the resulting nonli...

Tadesse, Tilaye; Inhester, B; MacNeice, P; Pevtsov, A; Sun, X

2012-01-01

313

Hematological responses after inhaling {sup 238}PuO{sub 2}: An extrapolation from beagle dogs to humans  

Energy Technology Data Exchange (ETDEWEB)

The alpha emitter plutonium-238 ({sup 238}Pu), which is produced in uranium-fueled, light-water reactors, is used as a thermoelectric power source for space applications. Inhalation of a mixed oxide form of Pu is the most likely mode of exposure of workers and the general public. Occupational exposures to {sup 238}PuO{sub 2} have occurred in association with the fabrication of radioisotope thermoelectric generators. Organs and tissue at risk for deterministic and stochastic effects of {sup 238}Pu-alpha irradiation include the lung, liver, skeleton, and lymphatic tissue. Little has been reported about the effects of inhaled {sup 238}PuO{sub 2} on peripheral blood cell counts in humans. The purpose of this study was to investigate hematological responses after a single inhalation exposure of Beagle dogs to alpha-emitting {sup 238}PuO{sub 2} particles and to extrapolate results to humans.

Scott, B.R.; Muggenburg, B.A.; Welsh, C.A.; Angerstein, D.A.

1994-11-01

314

Chiral extrapolation of the sigma and rho mesons from dispersion relations and Chiral Perturbation Theory  

CERN Document Server

We review our recent study of the pion mass dependence of the rho and sigma resonances, generated from one-loop SU(2) Chiral Perturbation Theory (ChPT) with the Inverse Amplitude Method (IAM). In order to properly account for the Adler zero region, we also review the recently obtained modified version of the IAM; which is based on analyticity, elastic unitarity and ChPT at low energies, thus yielding the correct pion mass dependence of the resonance pole positions up to next-to-leading order in ChPT. As main results we find that the rho-pi-pi coupling constant is almost pion mass independent and that the rho mass shows a smooth pion mass dependence while that of the sigma shows a strong non-analyticity. These findings are important for studies of the meson spectrum on the lattice.

Ríos, G; Hanhart, C; Peláez, J R

2008-01-01

315

Chiral extrapolation of the ? and ? mesons from dispersion relations and Chiral Perturbation Theory  

Science.gov (United States)

We review our recent study of the pion mass dependence of the ? and ? resonances, generated from one-loop SU(2) Chiral Perturbation Theory (ChPT) with the Inverse Amplitude Method (IAM). In order to properly account for the Adler zero region, we also review the recently obtained modified version of the IAM; which is based on analyticity, elastic unitarity and ChPT at low energies, thus yielding the correct pion mass dependence of the resonance pole positions up to next—to—leading order in ChPT. As main results we find that the ??? coupling constant is almost m? independent and that M? shows a smooth m? dependence while that of the ? shows a strong non-analyticity. These findings are important for studies of the meson spectrum on the lattice.

Ríos, G.; Nicola, A. Gómez; Hanhart, C.; Peláez, J. R.

2008-08-01

316

Extrapolating ecological risks of ionizing radiation from individuals to populations to ecosystems  

International Nuclear Information System (INIS)

Approaches for protecting ecosystems from ionizing radiation are quite different from those used for protecting ecosystems from adverse effects of toxic chemicals. The methods used for chemicals are conceptually similar to those used to assess risks of chemicals to human health in that they focus on the protection of the most sensitive or most highly exposed individuals. The assumption is that if sensitive or maximally exposed species and life stages are protected, then ecosystems will be protected. Radiological protection standards, on the other hand, are explicitly premised on the assumption that organisms, populations and ecosystems all possess compensatory capabilities to allow them to survive in the face of unpredictable natural variation in their environments. These capabilities are assumed to persist in the face of at least some exposure to ionizing radiation. The prevailing approach to radiological protection was developed more than 30 years ago, at a time when the terms risk assessment and risk management were rarely used. The expert review approach used to derive radiological protection standards is widely perceived to be inconsistent with the open, participatory approach that prevails today for the regulation of toxic chemicals. The available data for environmental radionuclides vastly exceeds that available for any chemical. Therefore, given an understanding of dose-response relationships for radiation effects and exposures for individual organisms, it shoexposures for individual organisms, it should be possible to develop methods for quantifying effects of radiation on populations. A tiered assessment scheme as well as available population models that could be used for the ecological risk assessment of radionuclides is presented. (author)

317

Dispersion relation approach to the extrapolation towards negative energy of the optical potential in 40Ca and 208Pb  

International Nuclear Information System (INIS)

Accurate empirical information on the nuclear mean field V(r; E) is available at positive energy but is lacking at negative energy. A dispersion relation approach is used to extrapolate the radial moments [rq]V(E)=(4?/A)?V(r; E)rq dr(q=0.8, 2, 4) of V(r; E) from positive to negative energies. The quantity V(r; E) is the sum of a Hartree-Fock type contribution VHF(r; E) and of a dispersive contribution ?V(r; E) which arises from the coupling between the elastic and nonelastic channels. A dispersion relation is used to evaluate [rq]?V(E) from the radial moments [rq]W(E) of the imaginary part of empirical optical-model potentials, in the case of protons and neutrons on 208Pb and of protons on 40Ca. It is assumed that the radial moments of VHF are either linear or quadratic functions of energy, whose parameters are determined by fitting the empirical values of [rq]V(E) associated with optical-model potentials which yield very good fits to the experimental cross sections; close agreement is found between the calculated and empirical values of [rq]V(E) for E>0. The dispersive corrections give rise to a characteristic energy dependence of the ratios [rq]V(E)/[rq]V(E) at low energy in particular of the mean square radius. The reliability of the extrapolation of the calculated [rq]V(E) towards negative energy is discussed by studying its sensitivity to the inputs of the model. This sensitivity can be reduced when one introduces a constraint at the Fermi energy EF. The meaningfulness of this type of constraint is discussed. (orig.)

318

Feasibility Study of Short-Term Storm Forecasting Over the Gulf of Mexico by Blending Satellite-Based Extrapolation Forecasts with Numerical Weather Prediction Results  

Science.gov (United States)

Deep convection over the ocean poses a potentially great danger for trans-oceanic flights, as tragically demonstrated by the Air France Flight 447 accident of 2009. This paper describes a forecasting system that will produce 0-12 hr convective forecasts over the Gulf of Mexico domain using a blending technique that combines satellite-based extrapolation forecasts with Numerical Weather Prediction (NWP) model forecasts. Closely following the steps of the Federal Aviation Administration (FAA) Aviation Weather Research Program (AWRP) CoSPA development, a forecasting system is being developed to blend satellite-derived rain rate and cloud top height with their corresponding fields derived from the Global Forecasting System (GFS) NWP model. Forecasts will be computed over the 0-12 hr time frame within a domain that encompasses the greater Gulf of Mexico and parts of the continental United States. Tests of various extrapolation techniques have been completed and an optimum technique has been selected. Both the extrapolated and the GFS rain rate forecast performance statistics have been compiled. Considering the relative strength of the NWP model and the satellite-based extrapolation forecasts, a dynamical-weighting technique, similar to what is being used in CoSPA, has been tested. The weights are determined by past performance of extrapolation and model forecasts as a function of forecast lead time. A prototype blended forecasting system for oceanic convection using dynamical-weighting techniques has been developed and preliminary results of the blended forecasting system will be reported at the conference.

Cai, H.; Kessinger, C.; Rehak, N.; Pinto, J. O.; Megenhardt, D.; Albo, D.; Phillips, C.; Bankert, R.; Hawkins, J.

2012-12-01

319

Extrapolating population size from the occupancy-abundance relationship and the scaling pattern of occupancy  

DEFF Research Database (Denmark)

The estimation of species abundances at regional scales requires a cost-efficient method that can be applied to existing broadscale data. We compared the performance of eight models for estimating species abundance and community structure from presence-absence maps of the southern African avifauna. Six models were based on the intraspecific occupancy-abundance relationship (OAR); the other two on the scaling pattern of species occupancy (SPO), which quantifies the decline in species range size when measured across progressively finer scales. The performance of these models was examined using five tests: the first three compared the predicted community structure against well-documented macroecological patterns; the final two compared published abundance estimates for rare species and the total regional abundance estimate against predicted abundances. Approximately two billion birds were estimated as occurring in South Africa, Lesotho, and Swaziland. SPO models outperformed the OAR models, due to OAR models assuming environmental homogeneity and yielding scale-dependent estimates. Therefore, OAR models should only be applied across small, homogenous areas. By contrast, SPO models are suitable for data at larger spatial scales because they are based on the scale dependence of species range size and incorporate environmental heterogeneity (assuming fractal habitat structure or performing a Bayesian estimate of occupancy). Therefore, SPO models are recommended for assemblage-scale regional abundance estimation based on spatially explicit presence-absence data.

Hui, Cang; McGeoch, Melodie A.

2009-01-01

320

Extrapolating psychological insights from Facebook profiles: a study of religion and relationship status.  

Science.gov (United States)

Online social network users may leave creative, subtle cues on their public profiles to communicate their motivations and interests to other network participants. This paper explores whether psychological predictions can be made about the motivations of social network users by identifying and analyzing these cues. Focusing on the domain of relationship seeking, we predicted that people using social networks for dating would reveal that they have a single relationship status as a method of eliciting contact from potential romantic others. Based on results from a pilot study (n = 20) supporting this hypothesis, we predicted that people attempting to attract users of the same religious background would report a religious affiliation along with a single relationship status. Using observational data from 150 Facebook profiles, results from a multivariate logistic regression suggest that people providing a religious affiliation were more likely to list themselves as single (a proxy for their interest in using the network to find romantic partners) than people who do not provide religious information. We discuss the implications for extracting psychological information from Facebook profiles. To our knowledge, this is the first study to suggest that information from publicly available online social networking profiles can be used to predict people's motivations for using social networks. PMID:19366321

Young, Sean; Dutta, Debo; Dommety, Gopal

2009-06-01

 
 
 
 
321

Corrosion and corrosion control of mild steel in concentrated H{sub 2}SO{sub 4} solutions by a newly synthesized glycine derivative  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Display Omitted Research highlights: GlyD1 exhibits inhibiting properties more than GlyD2 and Gly. Inhibition efficiency increases with inhibitor concentration. Inhibition efficiency decreases with temperature, suggesting physical adsorption. Validation of corrosion rates measured by Tafel extrapolation method is confirmed. - Abstract: A newly synthesized glycine derivative (GlyD1), 2-(4-(dimethylamino)benzylamino)acetic acid hydrochloride, was used to control mild steel corrosion in 4.0 M H{sub 2}SO{sub 4} solutions at different temperatures (278-338 K). Tafel extrapolation, linear polarization resistance (LPR) and impedance methods were used to test corrosion inhibitor efficiency. An independent method of chemical analysis, namely ICP-AES (inductively coupled plasma atomic emission spectrometry) was also used to test validity of corrosion rate measured by Tafel extrapolation method. Results obtained were compared with an available glycine derivative (GlyD2) and glycine (Gly). Tafel polarization measurements revealed that the three tested inhibitors function as mixed-type compounds. The inhibition efficiency increased with increase in inhibitor concentration and decreased with temperature, suggesting the occurrence of physical adsorption. The adsorptive behaviour of the three inhibitors followed Temkin-type isotherm and the standard free energy changes of adsorption ({Delta}G{sub ads}{sup o}) were evaluated for the three tested inhibitors as a function of temperature. The inhibition performance of GlyD1 was much better than those of GlyD2 and Gly itself. Results obtained from the different corrosion evaluation techniques were in good agreement.

Amin, Mohammed A., E-mail: maaismail@yahoo.co [Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566 (Egypt); Materials and Corrosion Lab (MCL), Department of Chemistry, Faculty of Science, Taif University, 888 Hawiya (Saudi Arabia); Ibrahim, Mohamed M. [Department of Chemistry, Faculty of Science, Kafr El-Sheikh University, Kafr El-Sheikh 33516 (Egypt); Materials and Corrosion Lab (MCL), Department of Chemistry, Faculty of Science, Taif University, 888 Hawiya (Saudi Arabia)

2011-03-15

322

Time extrapolation aspects in the performance assessment of high and medium level radioactive waste disposal in the Boom Clay at Mol (Belgium)  

International Nuclear Information System (INIS)

SCK-CEN is studying the disposal of high and long-lived medium level waste in the Boom Clay at Mol, Belgium. In the performance assessment for such a repository time extrapolation is an inherent problem due to the extremely long half-life of some important radionuclides. To increase the confidence in these time extrapolations SCK-CEN applies a combination of different experimental and modelling approaches including laboratory and in situ experiments, natural analogue studies, deterministic (or mechanistic) models and stochastical models. An overview is given of these approaches and some examples of applications to the different repository system components are given. (author)

323

A preliminary result of calculation of Extrapolated-to-Zero-Mesh-Size Solution (EZMSS) of the Second AER Kinetic benchmark with finite - difference code MAG  

International Nuclear Information System (INIS)

A preliminary result of calculation of Extrapolated-to-Zero-Mesh-Size Solution (EZMSS) for the Second AER Kinetic benchmark is presented. Calculation has been made with the code MAG. The standard MCFD (mesh - center finite difference) approximation in ?-Z geometry has been used for space approximation. The mesh refinement technique with h2 - extrapolation has been used to calculate EXMSS and to evaluate its accuracy. The preliminary result shows a significant difference with all known to author solutions generated earlier by nodal codes, in particular with DYN3D reference solution. The only exception is BIPR8 solution that seems to be rather close to preliminary estimation of the EZMSS. (Authors)

324

Denitrification in sediments as a major nitrogen sink in the Baltic Sea: an extrapolation using sediment characteristics  

Directory of Open Access Journals (Sweden)

Full Text Available Rates of denitrification in sediments were measured with the isotope pairing technique at different sites in the southern and central Baltic Sea. The rates varied between 0.5 ?mol N m?2 h?1 in sands and 28.7 ?mol N m?2 h?1 in muddy sediments and showed a good correlation to the organic carbon contents of the surface sediments. N-removal rates via sedimentary denitrification were estimated for the entire Baltic Sea calculating sediment specific denitrification rates and interpolating them to the whole Baltic Sea area. Another approach was carried out by using the relationship between the organic carbon content and the rate of denitrification. The N-removal by denitrification in sediments varied between 426–652 kt N a?1, which is around 48–73% of the external N inputs delivered via rivers, coastal point sources, and atmospheric deposition. Moreover, an expansion of the anoxic bottom areas was considered under the assumption of a rising oxycline from 100 to 80 m water depth. This leads to an increase of the area with anoxic conditions and an overall decrease in sedimentary denitrification by 14%. Overall, we show here that this type of data extrapolation is a powerful tool to estimate the nitrogen losses for a whole coastal sea and may be applicable to other coastal regions and enclosed seas.

B. Deutsch

2010-10-01

325

Denitrification in sediments as a major nitrogen sink in the Baltic Sea: an extrapolation using sediment characteristics  

Directory of Open Access Journals (Sweden)

Full Text Available Rates of denitrification in sediments were measured with the isotope pairing technique at different sites in the southern and central Baltic Sea. They varied between 0.5 ?mol m?2 h?1 in sands and 28.7 ?mol m?2 h?1 in muddy sediments and showed a good correlation to the organic carbon contents of the surface sediments. N-removal rates via sedimentary denitrification were estimated for the entire Baltic Sea calculating sediment specific denitrification rates and interpolating them to the whole Baltic Sea area. Another approach was carried out by using the relationship between the organic carbon content and the rate of denitrification. For the entire Baltic Sea the N-removal by denitrification in sediments varied between 426–652 kt N a?1, which is around 48–73% of the external N inputs delivered via rivers, coastal point sources and atmospheric deposition. Moreover, an expansion of the anoxic bottom areas was considered under the assumption of a rising oxycline from 100 to 80 m water depth. This leads to an increase of the area with anoxic conditions and an overall decrease in sedimentary denitrification by 14%. Overall we can show here that this type of data extrapolation is a powerful tool to estimate the nitrogen losses for a whole coastal sea and may be applicable to other coastal regions and enclosed seas, too.

B. Deutsch

2010-04-01

326

What you see may not always be what you get : Bioavailability and extrapolation from in vitro tests  

DEFF Research Database (Denmark)

In human risk assessment, bioavailability needs to be considered when relying on in vitro toxicity results. For single chemicals, this quantitative challenge is often handled through a bioavailability factor. For mixtures, however, things are more complicated. Thus, individual constituents may not only interact toxicodynamically and toxicokinetically, but the composition of constituents reaching the target site may also differ from what was present at the site of exposure due to the differences in their bioavailabilities. A recent study concluded on the in vivo potential of Australian tea-tree oil (TTO) to act as an endocrine disruptor based on an in vitro protocol measuring the growth of MCF-7 cells following chemical exposure to TTO. TTO is primarily used topically in humans, and is not a single chemical but is a mixture with some constituents penetrating the skin which others do not. The present study evaluated in an identical in vitro model to what extent TTO and its skin penetrating constituents affected the growth of MCF-7 cells. The estrogenic potency of TTO was confirmed, but none of the bioavailable TTO constituents demonstrated estrogenicity. The present study, therefore, cautions in vitro to in vivo extrapolations from the mixtures of constituents with potentially varying bioavailabilities. Udgivelsesdato: June

Nielsen, Jesper Bo

2008-01-01

327

Interspecies dose extrapolation for inhaled dimethyl sulfate: a PBPK model-based analysis using nasal cavity N7-methylguanine adducts.  

Science.gov (United States)

Dimethyl sulfate (DMS) is a volatile sulfuric acid ester used principally as a methylating agent in a wide variety of industrial applications. DMS reacts with organic macromolecules by a SN2 mechanism. The weight of experimental evidence suggests that DMS possesses genotoxic and carcinogenic potential. Inhalation studies have shown that repeated exposure to DMS leads to tumors in the nasal cavity and lower respiratory tract in both rats and mice. Here we present a quantitative assessment for cross-species dose extrapolation for inhaled DMS using a physiologically based pharmacokinetic (PBPK) model. The model is designed to simulate N7-methylguanine (N7 mG) DNA adduct levels in the nasal mucosa following DMS exposure in rats and humans. This model was parameterized and predictions were tested by comparison against experimentally measured N7 mG DNA adduct levels in rat nasal mucosa following inhalation exposure to DMS. The model-based interspecies dose comparison, using N7 mG adduct levels in the nasal respiratory tissue as the appropriate dose metrics, predicts a dose rate seven times higher in rats compared to humans. PMID:16036752

Sarangapani, Ramesh; Teeguarden, Justin G; Gentry, P Robinan; Clewell, Harvey J; Barton, Hugh A; Bogdanffy, Matthew S

2004-08-01

328

Searching for Inflationary B-modes: Can dust emission properties be extrapolated from 350 GHz to 150 GHz?  

CERN Document Server

Recent Planck results have shown that the path to isolating an inflationary B-mode signal in microwave polarization passes through understanding and modeling the interstellar dust polarized emission foreground, even in regions of the sky with the lowest level of dust emission. One of the most commonly used ways to remove the dust foreground is to extrapolate the polarized dust emission signal from frequencies where it dominates (e.g., 350 GHz) to frequencies commonly targeted by cosmic microwave background experiments (e.g., 150 GHz). We show, using a simple 2-cloud model, that if more than one cloud is present along the line-of-sight, with even mildly different temperature and dust column density, but severely misaligned magnetic field, then the 350 GHz polarized sky map is not predictive of that at 150 GHz. This problem is intrinsic to all microwave experiments and is due to information loss due to line-of-sight integration. However, it can be alleviated through interstellar medium tomography: a reconstruct...

Tassis, Konstantinos

2014-01-01

329

Enhanced confinement scenarios without large edge localized modes in tokamaks: control, performance, and extrapolability issues for ITER  

Science.gov (United States)

Large edge localized modes (ELMs) typically accompany good H-mode confinement in fusion devices, but can present problems for plasma facing components because of high transient heat loads. Here the range of techniques for ELM control deployed in fusion devices is reviewed. Two strategies in the ITER baseline design are emphasized: rapid ELM triggering and peak heat flux control via pellet injection, and the use of magnetic perturbations to suppress or mitigate ELMs. While both of these techniques are moderately well developed, with reasonable physical bases for projecting to ITER, differing observations between multiple devices are also discussed to highlight the needed community R&D. In addition, recent progress in ELM-free regimes, namely quiescent H-mode, I-mode, and enhanced pedestal H-mode is reviewed, and open questions for extrapolability are discussed. Finally progress and outstanding issues in alternate ELM control techniques are reviewed: supersonic molecular beam injection, edge electron cyclotron heating, lower hybrid heating and/or current drive, controlled periodic jogs of the vertical centroid position, ELM pace-making via periodic magnetic perturbations, ELM elimination with lithium wall conditioning, and naturally occurring small ELM regimes.

Maingi, R.

2014-11-01

330

CDNA CLONING OF FATHEAD MINNOW (PIMEPHALES PROMELAS) ESTROGEN AND ANDROGEN RECEPTORS FOR USE IN STEROID RECEPTOR EXTRAPOLATION STUDIES FOR ENDOCRINE DISRUPTING CHEMICALS  

Science.gov (United States)

cDNA Cloning of Fathead minnow (Pimephales promelas) Estrogen and Androgen Receptors for Use in Steroid Receptor Extrapolation Studies for Endocrine Disrupting Chemicals. Wilson, V.S.1,, Korte, J.2, Hartig P. 1, Ankley, G.T.2, Gray, L.E., Jr 1, , and Welch, J.E.1. 1U.S...

331

Hot tensile and creep rupture data extrapolation on 2.25Cr-1Mo steel using the CDM Penny-Kachanov methodology  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Hot tensile and creep data were obtained for 2.25Cr-1Mo steel, ASTM A387 Gr.22CL2, at the temperatures of 500-550-600-650-700 °C. Using the concept of equivalence between hot tensile data and creep data, the results were analyzed according to the methodology based on Kachanov Continuum Damage Mechan [...] ics proposed by Penny, which suggests the possibility of using short time creep data obtained in laboratory for extrapolation to long operating times corresponding to tens of thousands hours. The hot tensile data (converted to creep) define in a better way the region where ?=0 and the creep data define the region where ?=1, according to the methodology. Extrapolation to 10,000 h and 100,000 h is performed and the results compared with results obtained by other extrapolation procedures such as the Larson-Miller and Manson-Haferd methodologies. Extrapolation from ASTM and NIMS Datasheets for 10,000 h and 100,000 h as well as data from other authors on 2.25Cr-1Mo steel are used for assessing the reliability of the results.

José Francisco dos, Reis Sobrinho; Levi de Oliveira, Bueno.

2014-04-01

332

Assessment of the hepatic veins in poor contrast conditions using dual energy CT. Evaluation of a novel monoenergetic extrapolation software algorithm  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To evaluate a novel monoenergetic post-processing algorithm (MEI+) in patients with poor intrahepatic contrast enhancement. Materials and Methods: 25 patients were retrospectively included in this study. Late-phase imaging of the upper abdomen, which was acquired in dual-energy mode (100/140 kV), was used as a model for poor intrahepatic contrast enhancement. Traditional monoenergetic images (MEI), linearly weighted mixed images with different mixing ratios (MI), sole 100 and 140 kV and MEI+ images were calculated. MEI+ is a novel technique which applies frequency-based mixing of the low keV images and an image of optimal keV from a noise perspective to combine the benefits of both image stacks. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the intrahepatic vasculature (IHV) and liver parenchyma (LP) were objectively measured and depiction of IHV was subjectively rated and correlated with portal venous imaging by two readers in consensus. Results: MEI+ was able to increase the SNR of the IHV (5.7 ± 0.4 at 40 keV) and LP (4.9 ± 1.0 at 90 keV) and CNR (2.1 ± 0.6 at 40 keV) greatly compared to MEI (5.1 ± 1.1 at 80 keV, 4.7 ± 1.0 at 80 keV, 1.0 ± 0.4 at 70 keV), MI (5.2 ± 1.1 M5:5, 4.8 ± 1.0 M5:5, 1.0 ± 3.5 M9:1), sole 100 kV images (4.4 ± 1.0, 3.7 ± 0.8, 1.0 ± 0.3) and 140 kV images (2.8 ± 0.5, 3.1 ± 0.6, 0.1 ± 0.2). Subjective assessment rated MEI+ of virtual 40 keV superior to all other images. Conclusion: MEI+ is a very promising algorithm for monoenergetic extrapolation which is able to overcome noise limitations associated with traditional monoenergetic techniques at low virtual keV levels and consequently does not suffer from a decline of SNR and CNR at low keV values. This algorithm allows an improvement of IHV depiction in the presence of poor contrast. (orig.)

Schabel, C.; Bongers, M.; Grosse, U.; Mangold, S.; Claussen, C.D.; Thomas, C. [University Hospital of Tuebingen (Germany). Dept. of Diagnostic and Interventional Radiology; Sedlmair, M. [Siemens AG, Forchheim (Germany). Healthcare; Korn, A. [University Hospital of Tuebingen (Germany). Dept. of Diagnostic and Interventional Neuroradiology

2014-06-15

333

Assessment of the hepatic veins in poor contrast conditions using dual energy CT. Evaluation of a novel monoenergetic extrapolation software algorithm  

International Nuclear Information System (INIS)

Purpose: To evaluate a novel monoenergetic post-processing algorithm (MEI+) in patients with poor intrahepatic contrast enhancement. Materials and Methods: 25 patients were retrospectively included in this study. Late-phase imaging of the upper abdomen, which was acquired in dual-energy mode (100/140 kV), was used as a model for poor intrahepatic contrast enhancement. Traditional monoenergetic images (MEI), linearly weighted mixed images with different mixing ratios (MI), sole 100 and 140 kV and MEI+ images were calculated. MEI+ is a novel technique which applies frequency-based mixing of the low keV images and an image of optimal keV from a noise perspective to combine the benefits of both image stacks. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the intrahepatic vasculature (IHV) and liver parenchyma (LP) were objectively measured and depiction of IHV was subjectively rated and correlated with portal venous imaging by two readers in consensus. Results: MEI+ was able to increase the SNR of the IHV (5.7 ± 0.4 at 40 keV) and LP (4.9 ± 1.0 at 90 keV) and CNR (2.1 ± 0.6 at 40 keV) greatly compared to MEI (5.1 ± 1.1 at 80 keV, 4.7 ± 1.0 at 80 keV, 1.0 ± 0.4 at 70 keV), MI (5.2 ± 1.1 M5:5, 4.8 ± 1.0 M5:5, 1.0 ± 3.5 M9:1), sole 100 kV images (4.4 ± 1.0, 3.7 ± 0.8, 1.0 ± 0.3) and 140 kV images (2.8 ± 0.5, 3.1 ± 0.6, 0.1 ± 0.2). Subjective assessment rated MEI+ of virtual 40 keV superior to all other images. Conclusion: MEI+ is a very promising algorithm for monoenergetic extrapolation which is able to overcome noise limitations associated with traditional monoenergetic techniques at low virtual keV levels and consequently does not suffer from a decline of SNR and CNR at low keV values. This algorithm allows an improvement of IHV depiction in the presence of poor contrast. (orig.)

334

Communications: Intramolecular basis set superposition error as a measure of basis set incompleteness: Can one reach the basis set limit without extrapolation?  

Science.gov (United States)

One of only two error sources in the solution of the electronic Schrödinger equation is addressed: The basis set convergence (incompleteness) error (BSIE). The results of ab initio (first principles) correlated methods, for which the Møller-Plesset second order perturbation theory (MP2) was chosen as an example, were extrapolated to the complete basis set (CBS) limit using a Dunning-type basis set series. Basis sets as large as cc-pV5Z and cc-pV6Z were used. A representative molecular set that included nitrogen (N2), acetylene (C2H2), ethylene (C2H4), carbon dioxide (CO2), water (H2O), ammonia (NH3), hydrogen cyanide (HCN), and ethanol (C2H5OH) molecules was used for the calculations. The intramolecular basis set superposition error (BSSE) was found to be correlated with BSIE, meaning that intramolecular BSSE can be used as a measure of basis set incompleteness. The BSIE dependence on BSSE could be qualitatively approximated (±25%) by a power-law dependence: BSIE=A×BSSEp, where log10(A)=1.45±0.21 and p =1.27±0.09. This leads to the fact that CBS values at the MP2 theory level can be obtained using only one energy value and the corresponding intermolecular BSSE. The same power-law dependence was confirmed for all of the molecular systems studied. The universality of the BSIE versus BSSE dependence presented was checked using Pople-type basis sets. Even the results obtained with 6-311G, 6-311G??, and 6-311G(2df,2pd) basis sets were found to be nicely described by the same (universal) power law. Benchmark studies of nitrogen and acetylene contraction (compaction) showed that BSIE can be decreased by up to 83% (at the cc-pVTZ level) using the CBS-BSSE strategy described. The presented BSIE versus BSSE dependence can greatly aid in obtaining CBS results for large molecular systems of chemical or biological interest.

Balabin, Roman M.

2010-06-01

335

Nonlinear Force-Free Field Extrapolation of a Coronal Magnetic Flux Rope Supporting a Large-Scale Filament from Photospheric Vector Magnetogram  

CERN Document Server

Solar filament are commonly thought to be supported in magnetic dips, in particular, of magnetic flux ropes (FRs). In this Letter, from the observed photospheric vector magnetogram, we implement a nonlinear force-free field (NLFFF) extrapolation of a coronal magnetic FR that supports a large-scale intermediate filament between an active region and a weak polarity region. This result is the first in that current NLFFF extrapolations with presence of FRs are limited to relatively small-scale filaments that are close to sunspots and along main polarity inversion line (PIL) with strong transverse field and magnetic shear, and the existence of a FR is usually predictable. In contrast, the present filament lies along the weak-field region (photospheric field strength $\\lesssim 100$ G), where the PIL is very fragmented due to small parasitic polarities on both side of the PIL and the transverse field has a low value of signal-to-noise ratio. Thus it represents a far more difficult challenge to extrapolate a large-sc...

Jiang, Chaowei; Feng, Xueshang; Hu, Qiang

2014-01-01

336

Mathematical methods for physical and analytical chemistry  

CERN Document Server

Mathematical Methods for Physical and Analytical Chemistry presents mathematical and statistical methods to students of chemistry at the intermediate, post-calculus level. The content includes a review of general calculus; a review of numerical techniques often omitted from calculus courses, such as cubic splines and Newton's method; a detailed treatment of statistical methods for experimental data analysis; complex numbers; extrapolation; linear algebra; and differential equations. With numerous example problems and helpful anecdotes, this text gives chemistry students the mathematical

Goodson, David Z

2011-01-01

337

Extrapolating surface structures to depth in transpressional systems: the role of rheology and convergence angle deduced from analogue experiments  

Science.gov (United States)

The internal structure of major strike-slip faults is still poorly understood, particularly how the deep structure could be inferred from its surface expression (Molnar and Dayem, 2011 and references therein). Previous analogue experiments suggest that the convergence angle is the most influential factor (Leever et al., 2011). Further analogue modeling may allow a better understanding how to extrapolate surface structures to the subsurface geometry of strike-slip faults. Various scenarios of analogue experiments were designed to represent strike-slip faults in nature from different geological settings. As such key parameters, which are investigated in this study include: (a) the angle of convergence, (b) the thickness of brittle layer, (c) the influence of a rheological weak layer within the crust, and (d) influence of a thick and rheologically weak layer at the base of the crust. The latter aimed to simulate the effect of a hot metamorphic core complex or an alignment of uprising plutons bordered by a transtensional/transpressional strike-slip fault. The experiments are aimed to explain first order structures along major transcurrent strike-slip faults such as the Altyn, Kunlun, San Andrea and Greendale (Darfield earthquake 2010) faults. The preliminary results show that convergence angle significantly influences the overall geometry of the transpressive system with greater convergence angles resulting in wider fault zones and higher elevation. Different positions, densities and viscosities of weak rheological layers have not only different surface expressions but also affect the fault geometry in the subsurface. For instance, rheological weak material in the bottom layer results in stretching when experiment reaches a certain displacement and a buildup of a less segmented, wide positive flower structure. At the surface, a wide fault valley in the middle of the fault zone is the reflection of stretching along the velocity discontinuity at depth. In models with a thin and rheologically weaker layer in the middle of the brittle layer, deformation is distributed over more faults and the geometry of the fault zone below and above the weak zone shows significant differences, suggesting that the correlation of structures across a weak layer has to be supported by geophysical data, which help constraining the geometry of the deep part. This latter experiment has significantly similar phenomena in reality, such as few pressure ridges along Altyn fault. The experimental results underline the need to understand the role of the convergence angle and the influence of rheology on fault evolution, in order to connect between surface deformation and subsurface geometry. References Leever, K. A., Gabrielsen, R. H., Sokoutis, D., Willingshofer, E., 2011. The effect of convergence angle on the kinematic evolution of strain partitioning in transpressional brittle wedges: Insight from analog modeling and high-resolution digital image analysis. Tectonics, 30(2), TC2013. Molnar, P., Dayem, K.E., 2010. Major intracontinental strike-slip faults and contrasts in lithospheric strength. Geosphere, 6, 444-467.

Hsieh, Shang Yu; Neubauer, Franz; Cloetingh, Sierd; Willingshofer, Ernst; Sokoutis, Dimitrios

2014-05-01

338

A study of iteration method for 2-dimensional 2-group diffusion problems  

International Nuclear Information System (INIS)

It is shown that the Shanks sequence Esub(k)-transformation and the conventional extrapolation method are theoretically related. The Esub(1)sup(2)-transformation method is then applied for the multigroup diffusion probems. The diffusion code, CITATION, is modified for this study and the computing time is compared for each iteration tactics. The Equipose method, in which only single inner iteration for each energy group is carried for an outer iteration, has been known as the fastest iteration method. However, in the case of 2-group problems, the proposed method, in which the number of inner iteration for the fast and thermal group is 2 and 1 respectively, gives better convergency than the Equipose method by about 12 %. The double extrapolation method results in faster computing time than the single extrapolation method without computing storage problem. It is, however, to note that this method is verfied only for a two-group treatment. (Author)

339

Grafting of HEMA onto dopamine coated stainless steel by 60Co-? irradiation method  

Science.gov (United States)

A novel method for grafting of 2-hydroxyethyl methacrylate (HEMA) onto the surface of stainless steel (SS) was explored by using 60Co-? irradiation. The surface of SS was modified by coating of dopamine before radiation grafting. The grafting reaction was performed in a simultaneous irradiation condition. The chemical structures change of the surface before and after grafting was demonstrated by Fourier transform infrared (FTIR) spectrometer. The hydrophilicity of the samples was determined by water contact angle measurement in the comparison of the stainless steel in the conditions of pristine, dopamine coated and HEMA grafted. Surface morphology of the samples was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). The corrosion resistance properties of the samples were evaluated by Tafel polarization curve. The hemocompatibility of the samples were tested by platelet adhesion assay.

Jin, Wanqin; Yang, Liming; Yang, Wei; Chen, Bin; Chen, Jie

2014-12-01

340

Min-max Extrapolation Scheme for Fast Estimation of 3D Potts Field Partition Functions. Application to the Joint Detection-Estimation of Brain Activity in fMRI  

International Nuclear Information System (INIS)

In this paper, we propose a fast numerical scheme to estimate Partition Functions (PF) of symmetric Potts fields. Our strategy is first validated on 2D two-color Potts fields and then on 3D two- and three-color Potts fields. It is then applied to the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated, deactivated and inactivated brain regions and to estimate region dependent hemodynamic filters. For any brain region, a specific 3D Potts field indeed embodies the spatial correlation over the hidden states of the voxels by modeling whether they are activated, deactivated or inactive. To make spatial regularization adaptive, the PFs of the Potts fields over all brain regions are computed prior to the brain activity estimation. Our approach is first based upon a classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, we propose an extrapolation method that allows us to approximate the PFs associated to the Potts fields defined over the remaining brain regions. In comparison with preexisting methods either based on a path sampling strategy or mean-field approximations, our contribution strongly alleviates the computational cost and makes spatially adaptive regularization of whole brain fMRI datasets feasible. It is also robust against grid inhomogeneities and efficient irrespective of the topological confcient irrespective of the topological configurations of the brain regions. (authors)

 
 
 
 
341

Adverse Outcome Pathways and Systems Biology as Conceptual Approaches to Support Development of 21st Century Test Methods and Extrapolation Tools  

Science.gov (United States)

The proposed paradigm for ?Toxicity Testing in the 21st Century? supports the development of mechanistically-based, high-throughput in vitro assays as a potential cost effective and scientifically-sound alternative to some whole animal hazard testing. To accomplish this long-term...

342

Measurement of extrapolation curves for the secondary pattern of beta radiation Nr. 86 calibrated in rapidity of absorbed dose for tissue equivalent by the Physikalisch Technische Bundesanstalt  

International Nuclear Information System (INIS)

The following report has as objective to present the obtained results of measuring - with a camera of extrapolation of variable electrodes (CE) - the dose speed absorbed in equivalent fabric given by the group of sources of the secondary pattern of radiation Beta Nr. 86, (PSB), and to compare this results with those presented by the calibration certificates that accompany the PSB extended by the primary laboratory Physikalisch Technische Bundesanstalt, (PTB), of the R.F.A. as well as the uncertainties associated to the measure process. (Author)

343

Mapeamento digital de solos com base na extrapolação de mapas entre áreas fisiograficamente semelhantes / Digital soil mapping based on map extrapolation between physiographically similar areas  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste trabalho foi testar metodologias de mapeamento digital de solos (MDS) e avaliar a possibilidade de extrapolação de mapas entre áreas fisiograficamente semelhantes. A área de referência para o treinamento do modelo localizou-se no Município de Sentinela do Sul, RS, e a extrapolação f [...] oi feita para o Município Cerro Grande do Sul, RS. Desenvolveram-se pelo MDS modelos com o uso de variáveis ambientais, como preditoras, e as classes de solos - obtidas de um levantamento convencional na escala 1:50.000 - como variáveis dependentes. Testou-se o uso combinado de dois modelos de árvore de decisão (AD), treinados em duas paisagens com diferentes classes de drenagem. Para Sentinela do Sul, a concordância dos mapas preditos com os produzidos pelo levantamento convencional foi avaliada por matrizes de erro. Como a importância dos erros de mapeamento é variável, criou-se uma matriz ponderada, para atribuir diferentes importâncias aos erros específicos de mapeamento entre as distintas unidades de mapeamento. A acurácia do mapa de Cerro Grande do Sul foi avaliada pela verdade de campo. A extrapolação dos mapas gera resultados satisfatórios, com acurácia maior do que 75%. O uso de modelos com duas AD separadas por paisagens homogêneas gera mapas extrapolados com maior acurácia, avaliada pela verdade de campo. Abstract in english The objective of this work was to test methodologies for digital soil mapping (DSM) and to evaluate the possibility of map extrapolation between physiographically similar areas. The reference area for model training was located at the municipality of Sentinela do Sul, in the state of Rio Grand do Su [...] l (RS), Brazil, and the extrapolation was done for the municipality of Cerro Grande do Sul, RS. Models were developed by DSM using environmental variables as predictors, and soil classes - obtained from a conventional soil survey at 1:50,000 scale - as dependent variables. The combined use of two decision trees (DT), trained in two landscapes with different drainage classes, was tested. For Sentinela do Sul, the agreement between the predicted maps with the ones produced by conventional survey was evaluated using error matrices. Since the importance of mapping errors is variable, a weighted error matrix was created to assign different importances to specific mapping errors between different mapping units. Map accuracy of Cerro Grande do Sul was evaluated by ground truth. Map extrapolation yields satisfactory results, with accuracy higher than 75%. The use of models with two DTs divided by homogeneous landscapes generates extrapolated maps with a greater accuracy, evaluated by ground truth.

Pedro, Höfig; Elvio, Giasson; Pedro Rodolfo Siqueira, Vendrame.

2014-12-01

344

Determination of corrosion rate from electrode kinetic measurement  

International Nuclear Information System (INIS)

Electrode kinetic measurements provide a valuable technique for determining the corrosion rates of metals. The processes controlled by activation polarization are described by an exponential type of relation involving three unknowns. Corrosion behaviour of a metal can be fully described if these three parameters i.e. corrosion current, Ic and the two Tafel constants Beta/sub a/ and Beta/sub c/ are known. Experimentally the current density is measured as a function of the applied over relationship is such that an accurate determination of the three parameters by Ordinary Least Squares Fit is generally not possible. Various attempts have been made to simplify the equation using approximations. These are reflected in the well known methods such as Tafel Line Extrapolation and Linear Polarization. In Three Point and Four Point methods, selected data points are used which transform the original equation into similar relation such as a quadratic equation. Recently some computer based methods have been developed such as BETACRUNCH in which the method of averages is used. We have developed a new method to analyze experimental polarization data and determine the unknown parameters. We have formulated three independent relationships to solve for Ic, Ba and Beta/sub c/. In addition to the original version we have improved the methods by using some additional numerical approaches. These methods are robust and give accurate determination of Tafel constants and the corrosion currenf Tafel constants and the corrosion current density for a wide range of systems. Using the suggested scheme, it is also possible to avoid data corresponding to very low and very high over potentials and yet obtain excellent results. These methods are less sensitive to experimental errors as compared to other existing methods. (author)

345

Irradiation dose assessment in persons exposed to ionizing radiation through extrapolation of data from clinic-chemical changes in irradiated laboratory animals  

International Nuclear Information System (INIS)

An attempt is made to determine the dose within 24,48 and 72 hours of eventual exposure of healthy individuals to ionizing radiation through extrapolation of data retrieved from rats exposed to irradiation with 1, 3, 6 and 9 Gy X-rays. Seven clinic-chemical parameters are used: urea in the urine, taurine in the urine, urea in the serum, serum alkaline phosphatase, total serum lipids, sialic acid and thromboxane in the serum. A special formula is worked out and used for extrapolation of the experimental data, retrieved from irradiated rats, with due consideration to differences in the intensity of metabolic processes and species' radiosensitivity of rats and humans. The values of the aforementioned parameters that could be obtained upon eventual exposure of persons to ionizing irradiation are determined through computerization of the experimental data. It is believed that an accessible model for radiation dose assessment in the first three days after accidental exposure of human beings to ionizing irradiation is created. 5 refs., 4 figs. (author)

346

Creep-rupture-test on the stainless steel X6crni1811 (Din 1.494.8) in the frame of the Extrapolation-Program. (Part III)  

International Nuclear Information System (INIS)

The austenitic stainless steel X6crni1811 (Din 1.4948) used as a structure material for the German Fast Breeder Reactor SNR 300 was creep tested in a temperature range of 550-650 degree centigree material condition as well as welded material condition. The main point of this program (Extrapolation-Program) lies in the knowledge of the creep-rupture-strength and creep-behaviour up to 3 x 104 hours higher temperatures in order to extrapolated up to ?105 hours for operating temperatures. In order to study the stress dependency of the minimum creep rate additional tests were carried out of 550 degree centigree - 750 degree centigree. The present report describes the state in the running program with test-times of 23.000 hours and results from tests up to 55.000 hours belonging to other parallel programs are taken into account. Besides the creep-rupture behaviour it is also made a study of ductility between 550 and 750 degree centigree. Extensive metallographic examinations have been made to study the fracture behaviour and changes in structure. (Author)

347

Creep-rupture-test on the stainless steel X6CRNI1811 (DIN 1.4948) in the frame of the ''Extrapolation-Program''. (Part III)  

International Nuclear Information System (INIS)

The austenitic stainless steel X6CrNi1811 (DIN 1.4948) used as a structure material for the German Fast Breeder Reactor SNR 300 was creep tested in a temperature range of 550-650 deg under base material condition as well as welded material condition. The main point of this program (''Extrapolation-Program'') lies in the knowledge of the creep-rupture-strength and creepbehaviour up to 3 x 104 hours at higher temperatures in order to extrapolate up to >=105 hours for operating temperatures. In order to study the stress dependency of the minimum creep rate additional tests were carried out of 550 deg - 750 deg C. The present report describes the state in the running program with test-times of 23.000 hours and results from tests up to 55.000 hours belonging to other parallel programs are taken into account. Besides the creep-rupture behaviour it is also made a study of ductility between 550 and 750 deg C. Extensive metallographic examinations have been made to study the fracture behaviour and changes in structure. (author)

348

Creep-rupture-tests on thestainless steel X6 CrNi1811 (DIN 1.4948) in the frame of the ''Extrapolation-Program'' Pt. 2  

International Nuclear Information System (INIS)

The austenitic stainless steel X6 CrNi 1811 (DIN 1.4948) that is used as a structure material for the German Fast Breeder Reactor SNR 300 was creep tested in a temperature range of 550-650 deg under base material condition as well as welded material condition. The main point of this program (''Extrapolation-Program'') lies in the knowledge of the cree-rupture-strength and creep-behaviour up to 3X10-4 hours at higher temperatures in order to extrapolate up to (>=)105 hours for operating temperatures. In order to study the stress dependency of the minimum creep rate additional tests were carried out over temperature range 550 deg - 750 deg C. The present report describes the state in the running program with test-time up to 35.000 hours. Besides the cree-rupture behaviour it is possible to make a distinct quantitative statement for the creep-behaviour and ductility. Extensive metallographic examinations show the fracture behaviour and changes in structure. (author)

349

Creep-rupture-tests on the stainless steel X6CrNi 1811 (DIN 1.4948) in the frame of the Extrapolation-program. Pt. 3  

International Nuclear Information System (INIS)

The austenitic stainless steel X6CrNi1811 (DIN 1.4948) that is used as a structure material for the German Fast Breeder Reactor SNR 300 was creep-tested in a temperature range of 550-6500C under base material condition as well as welded material condition. The main point of this program ( Extrapolation Program ) lies in the knowledge of the creep-rupture-strength and creep-behaviour up to 3 x 104 hours at higher temperatures in order to extrapolate up to >= 105 hours for operating temperatures. In order to study the stress dependency of the minimum creep rate additional tests were carried out over temperature range of 550-7500C. The present report describes the state in the total running program with test-times up to 55 000 hours. Besides the creep-rupture behaviour it is possible to make a distinct quantitativ statement for the creep-behaviour and ductility. Extensive metallographic and electronmicroscopic examinations show the fracture behaviour and changes in structure. (orig.)

350

Numerical Evaluation of Feynman Integrals by a Direct Computation Method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A purely numerical method, Direct ComputationMethod is applied to evaluate Feynman integrals. This method is based on the combination of an efficient numerical integration and an efficient extrapolation. In addition, high-precision arithmetic and parallelization technique can be used in this method if required. We present the recent progress in development of this method and show results such as one-loop 5-point and two-loop 3-point integrals.

Yuasa, F.; Ishikawa, T.; Fujimoto, J.; Hamaguchi, N.; Doncker, E.; Shimizu, Y.

2009-01-01

351

Mapping coexistence lines via free-energy extrapolation: Application to order-disorder phase transitions of hard-core mixtures  

Science.gov (United States)

In this work, a variant of the Gibbs-Duhem integration (GDI) method is proposed to trace phase coexistence lines that combines some of the advantages of the original GDI methods such as robustness in handling large system sizes, with the ability of histogram-based methods (but without using histograms) to estimate free-energies and hence avoid the need of on-the-fly corrector schemes. This is done by fitting to an appropriate polynomial function not the coexistence curve itself (as in GDI schemes) but the underlying free-energy function of each phase. The availability of a free-energy model allows the post-processing of the simulated data to obtain improved estimates of the coexistence line. The proposed method is used to elucidate the phase behavior for two non-trivial hard-core mixtures: a binary blend of spheres and cubes and a system of size-polydisperse cubes. The relative size of the spheres and cubes in the first mixture is chosen such that the resulting eutectic pressure-composition phase diagram is nearly symmetric in that the maximum solubility of cubes in the sphere-rich solid (˜20%) is comparable to the maximum solubility of spheres in the cube-rich solid. In the polydisperse cube system, the solid-liquid coexistence line is mapped out for an imposed Gaussian activity distribution, which produces near-Gaussian particle-size distributions in each phase. A terminal polydispersity of 11.3% is found, beyond which the cubic solid phase would not be stable, and near which significant size fractionation between the solid and isotropic phases is predicted.

Escobedo, Fernando A.

2014-03-01

352

Extrapolating active layer thickness measurements across Arctic polygonal terrain using LiDAR and NDVI data sets  

Science.gov (United States)

attributes that vary with microtopography, such as active layer thickness (ALT), are labor intensive and difficult to document effectively through in situ methods at kilometer spatial extents, thus rendering remotely sensed methods desirable. Spatially explicit estimates of ALT can provide critically needed data for parameterization, initialization, and evaluation of Arctic terrestrial models. In this work, we demonstrate a new approach using high-resolution remotely sensed data for estimating centimeter-scale ALT in a 5 km2 area of ice-wedge polygon terrain in Barrow, Alaska. We use a simple regression-based, machine learning data-fusion algorithm that uses topographic and spectral metrics derived from multisensor data (LiDAR and WorldView-2) to estimate ALT (2 m spatial resolution) across the study area. Comparison of the ALT estimates with ground-based measurements, indicates the accuracy (r2 = 0.76, RMSE ±4.4 cm) of the approach. While it is generally accepted that broad climatic variability associated with increasing air temperature will govern the regional averages of ALT, consistent with prior studies, our findings using high-resolution LiDAR and WorldView-2 data, show that smaller-scale variability in ALT is controlled by local eco-hydro-geomorphic factors. This work demonstrates a path forward for mapping ALT at high spatial resolution and across sufficiently large regions for improved understanding and predictions of coupled dynamics among permafrost, hydrology, and land-surface processes from readily available remote sensing data.

Gangodagamage, Chandana; Rowland, Joel C.; Hubbard, Susan S.; Brumby, Steven P.; Liljedahl, Anna K.; Wainwright, Haruko; Wilson, Cathy J.; Altmann, Garrett L.; Dafflon, Baptiste; Peterson, John; Ulrich, Craig; Tweedie, Craig E.; Wullschleger, Stan D.

2014-08-01

353

Corrosion Behaviour of 18%Ni M250 Grade Maraging Steel under Welded Condition in Hydrochloric Acid Medium  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in english The corrosion behaviour of welded maraging steel in hydrochloric acid solutions was studied over a range of acid concentration and solution temperature by electrochemical techniques like Tafel extrapolation method and electrochemical impedance spectroscopy. The corrosion rate of welded maraging stee [...] l increases with the increase in temperature and concentration of hydrochloric acid in the medium. The energies of activation, enthalpy of activation and entropy of activation for the corrosion process were calculated. The surface morphology of the corroded sample was evaluated by surface examination using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS).

Pradeep, Kumar; A. Nityananda, Shetty.

2013-01-01

354

Corrosion inhibition of brass by aliphatic amines  

International Nuclear Information System (INIS)

Aliphatic amines hexylamine (HCA), octylamine (OCA) and decylamine (DCA) have been used as corrosion inhibitors for (70/30) brass in 0.I M HCIO4. The inhibitor efficiency (%P) calculated using weight loss, Tafel extrapolation, linear polarization and impedance methods was found to be in the order DCA> OCA> HCA. These adsorb on brass surface following bockris-swinkels' isotherm. DCA, OCA and HCA displaced 4, 3 and 2 molecules of water from interface respectively. Displacement of water molecules brought a great reorganization of double layer at the interface. These amines during corrosion form complexes with dissolved zinc and copper ions.(Author)

355

Static $\\bar{Q}Q$ pair free energy and screening masses from correlators of Polyakov loops: continuum extrapolated lattice results at the QCD physical point  

CERN Document Server

We study the correlators of Polyakov loops, and the corresponding gauge invariant free energy of a static quark-antiquark pair in 2+1 flavor QCD at finite temperature. Our simulations were carried out on $N_t$ = 6, 8, 10, 12, 16 lattices using Symanzik improved gauge action and a stout improved staggered action with physical quark masses. The free energies calculated from the Polyakov loop correlators are extrapolated to the continuum limit. For the free energies we use a two step renormalization procedure that only uses data at finite temperature. We also measure correlators with definite Euclidean time reversal and charge conjugation symmetry to extract two different screening masses, one in the magnetic, and one in the electric sector, to distinguish two different correlation lengths in the full Polyakov loop correlator.

Borsányi, Szabolcs; Katz, Sándor D; Pásztor, Attila; Szabó, Kálmán K; Török, Csaba

2015-01-01

356

Precision ground state mass of 12Be and an isobaric multiplet mass equation (IMME) extrapolation for 2+ and 02+ states in the T=2, A=12 multiplet  

International Nuclear Information System (INIS)

We report the mass measurement of the short-lived 12Be nuclide (T1/2=21.5 ms) performed using the Penning trap mass spectrometer TITAN at TRIUMF. Our mass excess value of 25 078.0(2.1) keV is in agreement with previous measurements, but is a factor of 7 more precise than the Atomic Mass Evaluation of 2003. To address an unresolved discussion on the spin assignment of isospin T=2 states in 12C and 12O, we reevaluate the isobaric mass multiplet equation for the lowest lying T=2 multiplet in the A=12 system and use the extracted parameters to extrapolate from the known excited 2+ and 0+ states in 12Be. Though this analysis favors the second known T=2 state in 12C to be 2+, 0+ cannot be excluded.

357

Analysis of the tritium inventory and permeation in a Li17Pb83 blanket proposed for INTOR and extrapolation to a power reactor  

International Nuclear Information System (INIS)

A transient tritium hold-up and permeation model is developed and applied to a simplified conceptual design of a water cooled Li17Pb83 blanket. Tritium inventories in the blanket associated with diffusivity, solubility and trapping effects are estimated. The model is applied to the INTOR/NET LiPb blanket design. Assuming a daily LiPb reprocessing frequency a tritium production rate of 64 grams per day yields a total tritium inventory in the blanket comparable to that of the tritium system or trapped in the first wall. The diffusion-limited permeation rate (neglecting oxide layers effects) reaches 4.2 g/day. The extrapolation of these results to reactor relevant conditions aggravates the permeation and the associated problems. (author)

358

Modeling the systemic retention of beryllium in rat. Extrapolation to human; Modelizacion de la retencion sistemica del berilio en la rata. Extrapolacion al Hombre  

Energy Technology Data Exchange (ETDEWEB)

In this work, we analyzed different approaches, assayed in order to numerically describe the systemic behaviour of Beryllium. The experimental results used in this work, were previously obtained by Furchner et al. (1973), using Sprague-Dawley rats, and others animal species. Furchner's work includes the obtained model for whole body retention in rats, but not for each target organ. In this work we present the results obtained by modeling the kinetic behaviour of Beryllium in several target organs. The results of this kind of models were used in order to establish correlations among the estimated kinetic constants. The parameters of the model were extrapolated to humans and, finally, compared with others previously published. (Author) 12 refs.

Montero Prieto, M.; Vidania Munoz, R. de

1994-07-01

359

Extrapolation of data from simulant-material experiments to the work potential of fuel penetrating through upper core structures in core disruptive accidents  

International Nuclear Information System (INIS)

This report addresses questions that arose after having completed a detailed study of a simulant-material experimental investigation of flow dynamics in the Upper Core Structures during a Core Disruptive Accident of a Liquid-Metal Fast Breeder Reactor. The main findings of the experiments were about the reduction of work potential of the expanding fuel by the presence of the Upper Core Structures. This report describes how the experimental data can be extrapolated to prototypic conditions, which phenomena modelled in code predictions by SIMMER-II are different for simulant and prototypic transients, and how the experimental results compare to effects of prototypic phenomena which could not be modelled in the experiment. (orig.)

360

Is the beagle dog an appropriate experimental animal for extrapolating data to humans on organ distribution patterns of U, Th, and Pu  

International Nuclear Information System (INIS)

Concentrations and organ distribution patterns of alpha-emitting isotopes of U (238U and 234U), Th (232Th, 230Th, and 228Th), and Pu (239,240Pu) were determined for beagle dogs of our colony. The dogs were exposed to environmental levels of U and Th isotopes through ingestion (food and water) and inhalation to stimulate environmental exposures of the general human population. The organ distribution patterns of these radionuclides in beagles are compared to patterns in humans to determine if it is appropriate to extrapolate organ content data from beagles to humans. The results indicated that approximately 80% of the U and Th accumulated in bone in both species. The organ content percentages of these radionuclides in soft tissues such as liver, kidney, etc. of both species were comparable. The human lung contained higher percentages of U and Th than the beagle lung, perhaps because the longer life span of humans resulted in a longer exposure time. If the U and Th content of dog lung is normalized to an exposure time of 58 y and 63 y, median ages of the U and Th study populations, respectively, the lung content for both species is comparable. The organ content of 239,240Pu in humans and beagles differed slightly. In the beagle, the liver contained more than 60%, and the skeleton contained less than 40% of the Pu body content. In humans, the liver contained approximately 37%, and the skeleton contained approximately 58% of the body content. This difference may have been dy content. This difference may have been due to differences in the mode of intake of Pu in each species or to differences in the chemical form of Pu. In general, the results suggest that the beagle may be an appropriate experimental animal from which to extrapolate data to humans with reference to the percentage of U, Th, and Pu found in the organs

 
 
 
 
361

Absolute abundance and function of intestinal drug transporters: a prerequisite for fully mechanistic in vitro-in vivo extrapolation of oral drug absorption.  

Science.gov (United States)

The use of whole body physiological-based pharmacokinetic (PBPK) models linked with in vitro-in vivo extrapolation (IVIVE) of kinetic parameters from laboratory experiments, has become embedded within many of the pharmaceutical industry and is used even as part of regulatory submissions. These include the influence of transporter proteins on drug disposition, a subject for which we have witnessed an increasing awareness. A combination of the development of high-powered analytical techniques and antibody-based technology, together with a realization that an understanding of absolute transporter protein abundances together with activity can potentially enhance the modelling of transporter kinetics by PBPK-IVIVE link models. This review summarizes the mechanistic approaches to integrate suitable non-biased in vitro transporter kinetic data relevant to the intestine (i.e. 'intrinsic' K(i) , 'intrinsic' K(m) ), by in vitro system modelling for these kinetic inputs with the advantages of, and challenges for, generating these data for input into PBPK models. This step is considered as a prerequisite for mechanistic modelling of the oral absorption for drugs that are substrates for transporters. Various approaches are provided to integrate intestinal transporter expression into PBPK models with a perspective on the incorporation of the absolute abundance/activity of transporters to enhance the predictive power of the models. We define the key intestinal tissue and functional expression-based scaling factors required. The objective is to use these for facilitating the extrapolation from in vitro intestinal transporter assays to the in vivo system, using absolute quantification methodologies. The models could be used to elucidate the complex relationship and relative importance of metabolizing enzymes and transporters in drug disposition and toxicity. PMID:22927116

Harwood, M D; Neuhoff, S; Carlson, G L; Warhurst, G; Rostami-Hodjegan, A

2013-01-01

362

An empirical method to correlate and predict solute distribution in ternary liquid-liquid systems  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a method that combines activity coefficient models with Hand's equation for tie lines. The proposed method calculates solute distribution in liquid-liquid ternary systems. The combination improves the calculated solute distributions using activity coefficient models while Hand's equation gives a good correlation of the experimental tie lines. The method could be used to extrapolate experimental information.

Zamaro J.M.

2002-01-01

363

Experimental Demonstration of High Frequency ELM Pacing by Pellet Injection on DIII-D and Extrapolation to ITER  

International Nuclear Information System (INIS)

Full text: Pellet pacing of edge localized modes (ELMs), which is the triggering of rapid small ELMs by pellet injection, has been proposed as a method to prevent large ELMs that can erode the ITER plasma facing components. D2 pellet injection has been used on the DIII-D tokamak to successfully demonstrate for the first time the pacing of ELMs at a 10 x higher rate than natural ELMs. The demonstration of ELM pacing on DIII-D was made by injecting slow (2 pellets at 60 Hz from the low field side in an ITER shaped plasma with a low natural ELM frequency of 5 Hz, q95 = 3.5, ?N = 1.8, and normalized energy confinement factor H98 = 1.1, with the input power only slightly above the H-mode threshold. The non-pellet similar discharges have ELM energy losses up to 50 kJ (? 8 % of total stored energy), while the case with pellets was able to demonstrate 60 Hz ELMs with an average ELM energy loss less than 5 kJ (< 1% of the total). Total divertor heat flux from the ELMs is reduced by more than a factor of 10 as measured by a fast framing IR camera. Central impurity accumulation of Ni is significantly reduced by the application of the 60 Hz pellets. No significant increase in density or decrease in energy confinement with the pellets was observed. Experimental details have shown that the ELMs are triggered before the pellets reach the top of the H-mode pressure pedestal, implying that very small shallow stal, implying that very small shallow penetrating pellets would be sufficient to trigger ELMs. Fast camera images of the pellets entering the plasma from the low field side show a local triggering phenomenon. A single plasma filament becomes visible near the pellet cloud and strikes the outer vessel wall within 200 ?s followed by additional ejected filaments. The implications of these results for possible pellet ELM pacing on ITER will be discussed. (author)

364

The inverse dose-rate effect and the extrapolation of radon risk estimates from exposures of miners to low-level exposures in homes  

International Nuclear Information System (INIS)

This letter is written in response to a paper in which the author discusses the inverse dose-rate dependence of oncogenic transformation by high-LET radiation. The author asserts that, as a consequence, the extrapolation of results from miners exposed to high levels of radon daughters could overestimate the risk due to environmental exposures. By using a model increased cell sensitivity in one part of the cell cycle, the author assumes an inverse dose-rate effect should occur only at high doses, but the author of this letter points out that this does not imply a lower risk per unit dose at low doses. According to this letter, the existence of an inverse dose-rate effect for high-LET radiation provides no grounds for projecting lower lung cancer risks per unit exposure at environmental radon levels than at the higher radon level in mines. Failure to adjust for any inverse dose-rate effect in the studies of miners can only lead to an underestimation of the environmental risk

365

Extrapolation of in situ data from 1-km squares to adjacent squares using remote sensed imagery and airborne lidar data for the assessment of habitat diversity and extent.  

Science.gov (United States)

Habitat surveillance and subsequent monitoring at a national level is usually carried out by recording data from in situ sample sites located according to predefined strata. This paper describes the application of remote sensing to the extension of such field data recorded in 1-km squares to adjacent squares, in order to increase sample number without further field visits. Habitats were mapped in eight central squares in northeast Estonia in 2010 using a standardized recording procedure. Around one of the squares, a special study site was established which consisted of the central square and eight surrounding squares. A Landsat-7 Enhanced Thematic Mapper Plus (ETM+) image was used for correlation with in situ data. An airborne light detection and ranging (lidar) vegetation height map was also included in the classification. A series of tests were carried out by including the lidar data and contrasting analytical techniques, which are described in detail in the paper. Training accuracy in the central square varied from 75 to 100 %. In the extrapolation procedure to the surrounding squares, accuracy varied from 53.1 to 63.1 %, which improved by 10 % with the inclusion of lidar data. The reasons for this relatively low classification accuracy were mainly inherent variability in the spectral signatures of habitats but also differences between the dates of imagery acquisition and field sampling. Improvements could therefore be made by better synchronization of the field survey and image acquisition as well as by dividing general habitat categories (GHCs) into units which are more likely to have similar spectral signatures. However, the increase in the number of sample kilometre squares compensates for the loss of accuracy in the measurements of individual squares. The methodology can be applied in other studies as the procedures used are readily available. PMID:25648761

Lang, M; Vain, A; Bunce, R G H; Jongman, R H G; Raet, J; Sepp, K; Kuusemets, V; Kikas, T; Liba, N

2015-03-01

366

Extrapolation of diclofenac clearance from in vitro microsomal metabolism data: role of acyl glucuronidation and sequential oxidative metabolism of the acyl glucuronide.  

Science.gov (United States)

Diclofenac is eliminated predominantly (approximately 50%) as its 4'-hydroxylated metabolite in humans, whereas the acyl glucuronide (AG) pathway appears more important in rats (approximately 50%) and dogs (>80-90%). However, previous studies of diclofenac oxidative metabolism in human liver microsomes (HLMs) have yielded pronounced underprediction of human in vivo clearance. We determined the relative quantitative importance of 4'-hydroxy and AG pathways of diclofenac metabolism in rat, dog, and human liver microsomes. Microsomal intrinsic clearance values (CL(int) = V(max)/K(m)) were determined and used to extrapolate the in vivo blood clearance of diclofenac in these species. Clearance of diclofenac was accurately predicted from microsomal data only when both the AG and the 4'-hydroxy pathways were considered. However, the fact that the AG pathway in HLMs accounted for ~75% of the estimated hepatic CL(int) of diclofenac is apparently inconsistent with the 4'-hydroxy diclofenac excretion data in humans. Interestingly, upon incubation with HLMs, significant oxidative metabolism of diclofenac AG, directly to 4'-hydroxy diclofenac AG, was observed. The estimated hepatic CL(int) of this pathway suggested that a significant fraction of the intrahepatically formed diclofenac AG may be converted to its 4'-hydroxy derivative in vivo. Further experiments indicated that this novel oxidative reaction was catalyzed by CYP2C8, as opposed to CYP2C9-catalyzed 4'-hydroxylation of diclofenac. These findings may have general implications in the use of total (free + conjugated) oxidative metabolite excretion for determining primary routes of drug clearance and may question the utility of diclofenac as a probe for phenotyping human CYP2C9 activity in vivo via measurement of its pharmacokinetics and total 4'-hydroxy diclofenac urinary excretion. PMID:12438516

Kumar, Sanjeev; Samuel, Koppara; Subramanian, Ramaswamy; Braun, Matthew P; Stearns, Ralph A; Chiu, Shuet-Hing Lee; Evans, David C; Baillie, Thomas A

2002-12-01

367

Scale extrapolation for the first wall of fusion reactor DEMO of deuterium recycling parameter in MANET obtained in a plasma simulator of JRC/IAM/ISPRA  

International Nuclear Information System (INIS)

The paper presents the main characteristics of the plasma/implantation/recycling experiment been carried out at the IAM, JRC-Ispra. The modelling aspects for the case of deuterium bombardment in martensitic steel DIN 1.9141 (MANET) are detailed. Once verified that release is surface-limited the surface constants, recombination (K2) and dissociation (K1) constants are determined by fitting the experimental pressure due to the gas desorbed in the measuring chamber. The values obtained for the dissociation constant are: K1=7.10''-6 (mol.Pa''-1.m''-2.s''-1). The recombination constant K2 follows the Arrhenius law:?.K2=2.414* exp(-1571/RT) (m''4.mol''-1.s''-1), R=8.314 J.mol''-1. K''-1 (?:sticking factor). We have obtained quite high reflection coefficients (R>80%) in good agreement with other existing results and with the classical low-energy scattering theory. For temperatures ranging between: 300 and 600 K, ionic fluxes between: 2.10''20??(m''-2 s''-1)?1.10''21 and ion energies for D3 ''+ from 150 to 300 eV the obtained results for K2, K1 and R show a light dispersion. Activation energies for dissociation and recombination are comparable to those obtained from permeation experiments. The design of our experiment allows simple but accurate scale-extrapolations for the tracking of tritium at the First Wall of fusion reactor DEMO. Without taking into consideration other structura into consideration other structural phenomena (erosion. redeposition,...) having synergistic effects, the results obtained would minimise the negative impact of tritium related problems for the design of the First Wall of fusion reactor DEMO. (Author) 6 refs

368

CORRECTING ACCOUNTING RESULTS OF TENSIONS USING FEM BY HSS METHOD  

Directory of Open Access Journals (Sweden)

Full Text Available The usage of the Hot Spot Stress (HSS method by means of linear surface extrapolation (LSE approach was analyzed for the correction of results of the Finite-Element Method (FEM in case of singularity of stresses. The given examples of structures and testing examples were computed on the base of design-and-computation software SCAD for Windows (version 11.3.

D. O. Bannikov

2011-05-01

369

Deve-se extrapolar o tratamento de bronquiectasias em pacientes com fibrose cística para aqueles com bronquiectasias de outras etiologias? / Should the bronchiectasis treatment given to cystic fibrosis patients be extrapolated to those with bronchiectasis from other causes?  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Conhecer o perfil de pacientes adultos com bronquiectasias, comparando portadores de fibrose cística (FC) com aqueles com bronquiectasias de outra etiologia, a fim de determinar se é racional extrapolar terapêuticas instituídas em fibrocísticos para aqueles com bronquiectasias de outras et [...] iologias. MÉTODOS: Análise retrospectiva dos prontuários de 87 pacientes adultos com diagnóstico de bronquiectasia em acompanhamento em nosso serviço. Pacientes com doença secundária a infecção por tuberculose corrente ou no passado foram excluídos. Foram avaliados dados clínicos, funcionais e terapêuticos dos pacientes. RESULTADOS: Dos 87 pacientes com bronquiectasias, 38 (43,7%) tinham diagnóstico confirmado de FC através de dosagem de sódio e cloro no suor ou análise genética, enquanto 49 (56,3%) apresentavam a doença por outra etiologia, 34 (39,0%) desses com bronquiectasia idiopática. Os pacientes com FC apresentavam média de idade ao diagnóstico mais baixa (14,2 vs. 24,2 anos; p Abstract in english OBJECTIVE: To profile the characteristics of adult patients with bronchiectasis, drawing comparisons between cystic fibrosis (CF) patients and those with bronchiectasis from other causes in order to determine whether it is rational to extrapolate the bronchiectasis treatment given to CF patients to [...] those with bronchiectasis from other causes. METHODS: A retrospective analysis of the medical charts of 87 patients diagnosed with bronchiectasis and under follow-up treatment at our outpatient clinic. Patients who had tuberculosis (current or previous) were excluded. We evaluated the clinical, functional, and treatment data of the patients. RESULTS: Of the 87 patients with bronchiectasis, 38 (43.7%) had been diagnosed with CF, through determination of sweat sodium and chloride concentrations or through genetic analysis, whereas the disease was due to another etiology in 49 (56.3%), of whom 34 (39.0%) had been diagnosed with idiopathic bronchiectasis. The mean age at diagnosis was lower in the patients with CF than in those without (14.2 vs. 24.2 years; p

Rodrigo Abensur, Athanazio; Samia Zahi, Rached; Ciro, Rohde; Regina Carvalho, Pinto; Frederico Leon Arrabal, Fernandes; Rafael, Stelmach.

2010-08-01

370

Method of defect sizing by transient thermography  

International Nuclear Information System (INIS)

Most of NDT techniques used in industry have many advantages as well as limitations. A useful NDT technique must be able to determine the size of defect accurately during inspection. Transient thermography technique offers a fast, non-contact method and covers a large area for inspection. The paper will illustrate the FWHMs approach of determining the size of various defects (2, 3, 5, 8 and 10 mm) in diameters. The results obtained via this method shows that a good estimation of the defect size can be obtained by extrapolating a time series when time, t = 0. A comparison with numerical modelling and experimental data is presented. (Author)

371

Assessment of the susceptibility of lacquered tinplate cans to corrosion in different solutions using electrochemical methods / Evaluación de la susceptibilidad a la corrosión de recipientes de hojalata en diferentes soluciones usando técnicas electroquímicas  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish La corrosión de recipientes fabricados en hojalata expuestos a diferentes soluciones fue evaluada usando técnicas eletroquímicas. Los recipientes con y sin la aplicación de barniz fueron expuestos a diferentes soluciones. La susceptibilidad a sufrir corrosión se evaluó utilizando voltametría cíclica [...] , curvas de polarización y espectroscopia de impedancia electroquímica. La posibilidad de formación de películas pasivas en la superfi cie de los recipientes se evaluó según la histéresis presente en el primer ciclo de las medidas de voltametría. Las curvas de polarización revelaron que el comportamiento del recubrimiento de estaño puede cambiar de anódico a catódico según la naturaleza de la solución en contacto con el recipiente, alertando sobre el riesgo de corrosión localizada. Mediante impedancia electroquímica se evaluó el efecto del uso de un aditivo en las soluciones o productos empacados en dos recipientes. Las medidas de impedancia mostraron un efecto perjudicial del aditivo utilizado y una rápida aparición de procesos corrosivos cuando se usó la solución modifi cada con el aditivo. Abstract in english Corrosion of lacquered tinplate cans in different solutions was assessed using electrochemical methods. Samples with and without lacquer coating were exposed to different solutions and their susceptibility to corrosion was evaluated using cyclic voltammetry, Tafel curves and electrochemical impedanc [...] e spectroscopy. The possible formation of a passive layer on the container surface was evaluated according to the kind of hysteresis presented in the fi rst cycle of voltammeter measurements. Tafel plots showed how the behaviour of the tin layer can change from anodic to cathodic depending on the nature of the solution in contact with it, revealing the risk of localized corrosion. The effect of one additive in the solutions on the electrochemical performance containers was evaluated by electrochemical impedance. The impedance showed a deleterious effect of the additive, and corrosion processes appeared more quickly in containers packed with solutions modifi ed with additive.

Jorge A, Calderón; Carmen P, Buitrago.

2007-12-01

372

Composition between mecd and runge-Kutta algorithm method for large system of second order differential equations  

International Nuclear Information System (INIS)

NECD Method and runge-Kutta method for large system of second order ordinary differential equations in comparing algorithm. The paper introduce a extrapolation method used for solving the large system of second order ordinary differential equation. We call this method the modified extrapolated central difference (MECD) method. for the accuracy and efficiency MECD method. we compare the method with 4-th order runge-Kutta method. The comparison results show that, this method has almost the same accuracy as the 4-th order runge-Kutta method, but the computation time is about half of runge-Kutta. The MECD was declare by the author and Tetsuhiko Miyoshi of the Dept. Applied Science Yamaguchi University Japan

373

Report on the uncertainty methods study  

International Nuclear Information System (INIS)

The Uncertainty Methods Study (UMS) Group, following a mandate from CSNI, has compared five methods for calculating the uncertainty in the predictions of advanced 'best estimate' thermal-hydraulic codes: the Pisa method (based on extrapolation from integral experiments) and four methods identifying and combining input uncertainties. Three of these, the GRS, IPSN and ENUSA methods, use subjective probability distributions, and one, the AEAT method, performs a bounding analysis. Each method has been used to calculate the uncertainty in specified parameters for the LSTF SB-CL-18 5% cold leg small break LOCA experiment in the ROSA-IV Large Scale Test Facility (LSTF). The uncertainty analysis was conducted essentially blind and the participants did not use experimental measurements from the test as input apart from initial and boundary conditions. Participants calculated uncertainty ranges for experimental parameters including pressurizer pressure, primary circuit inventory and clad temperature (at a specified position) as functions of time

374

An improved Compton scattering method for determination of concentration of solutions.  

Science.gov (United States)

An improved Compton scattering method for determination of concentration of low-Z solutions is presented. The Monte Carlo (MC) numerical simulation of the scattering phenomena is done using the MCNP code. A unique non-linear extrapolation method is followed in correcting the scattered intensity for self-absorption and multiple scattering. The density ratios obtained using non linear extrapolated scattered intensity values are free from self-absorption and multiple scattering and agree well with the standard ones within experimental errors. The sensitivity study of transmission and scattering methods for determination of concentration of solutions having closer attenuation parameters at 661.6 keV is carried out to predict the range of effectiveness and suitability of these methods. The slopes (sensitivity/unit concentration) of the curves obtained from scattering method are higher by a factor of 1.26 compared to those of the transmission method in the measured range of concentrations. PMID:22871448

Priyada, P; Ramar, R; Shivaramu

2012-10-01

375

A method for measuring light ion reaction cross sections  

Energy Technology Data Exchange (ETDEWEB)

An experimental procedure for measuring reaction cross sections of light ions in the energy range 20-50 MeV/nucleon, using a modified attenuation technique, is described. The detection method incorporates a forward detector that simultaneously measures the reaction cross sections for five different sizes of the solid angles in steps from 99.1 to 99.8% of the total solid angle. The final reaction cross section values are obtained by extrapolation to the full solid angle.

Carlson, R.F. [Univ. of Redlands, CA (United States). Dept. of Physics; Ingemarsson, A.; Lantz, M. [Uppsala Univ. (Sweden). Dept. of Radiation Sciences] [and others

2005-03-01

376

New Field-Theoretic Method for the Virial Expansion  

Science.gov (United States)

We develop a graphical method for computing the virial expansion coefficients for a nonrelativistic quantum field theory. As an example we compute the third virial coefficient b3 for unitary fermions, a nonperturbative system. By calculating several graphs and performing an extrapolation, we arrive at b3=-0.2930, within 0.7% of a recent computation b3=-0.29095295 by Liu, Hu, and Drummond, which involved summing 10 000 energy levels for three unitary fermions in a harmonic trap.

Kaplan, David B.; Sun, Sichun

2011-07-01

377

The discrete ordinates method compared to Carlvik's and Syros's methods for anisotropic neutron scattering in slabs  

International Nuclear Information System (INIS)

The discrete ordinates method has been used to determine the criticality factor of infinite slabs with monoenergetic neutrons scattering anisotropically. The slab thickness was 0.2, 1, 2 or 20 mean free paths and the average cosine of the scattering angle 0, 0.1, or 0.2. The calculations were extended up to the S32 approximation for the thinnest slab. It was found that the Ssub(n) results extrapolate towards the values obtained by Dahl and Sjostrand using Carlvik's method. The reason why Syros and Theocharopoulos obtained deviating results is not known. (author)

378

Population survey sampling methods in a rural African setting : measuring mortality  

Digital Repository Infrastructure Vision for European Research (DRIVER)

BACKGROUND: Population-based sample surveys and sentinel surveillance methods are commonly used as substitutes for more widespread health and demographic monitoring and intervention studies in resource-poor settings. Such methods have been criticised as only being worthwhile if the results can be extrapolated to the surrounding 100-fold population. With an emphasis on measuring mortality, this study explores the extent to which choice of sampling method affects the representativeness of 1% sa...

Fottrell, Edward; Byass, Peter

2008-01-01

379

On the equivalence of LIST and DIIS methods for convergence acceleration  

CERN Document Server

Self-consistent field extrapolation methods play a pivotal role in quantum chemistry and electronic structure theory. We here demonstrate the mathematical equivalence between the recently proposed family of LIST methods [J. Chem. Phys. 134, 241103 (2011); J. Chem. Theory Comput. 7, 3045 (2011)] with Pulay's DIIS [Chem. Phys. Lett. 73, 393 (1980)]. Our results also explain the differences in performance among the various LIST methods.

Garza, Alejandro J

2014-01-01

380

Investigating Jamming percolation using renormalization group methods  

Science.gov (United States)

We develop renormalization group-based methods to determine the percolation threshold and exponents for jamming-percolation models. Such models exhibit mixed phase transitions in finite dimensions, with a discontinuous jump in the order parameter and an exponentially diverging length scale: ? (|p-pc^?|^?), where pc^? marks the percolation transition for the infinite system. To extract pc^? we use a Monte-Carlo scheme to find pc(L) for increasing L and extrapolate to L->?. We investigate several models in two dimensions to test for universality of the exponent ?.

Schoenholz, Samuel; Bug, Amy; Liu, Andrea

2010-03-01

 
 
 
 
381

Characterization of an extrapolation chamber and radiochromic films for verifying the metrological coherence among beta radiation fields; Caracterizacao de uma camara de extrapolacao e filmes radiocromicos para verificacao da coerencia metrologica entre campos padroes de radiacao beta  

Energy Technology Data Exchange (ETDEWEB)

The metrological coherence among standard systems is a requirement for assuring the reliability of dosimetric quantities measurements in ionizing radiation field. Scientific and technologic improvements happened in beta radiation metrology with the installment of the new beta secondary standard BSS2 in Brazil and with the adoption of the internationally recommended beta reference radiations. The Dosimeter Calibration Laboratory of the Development Center for Nuclear Technology (LCD/CDTN), in Belo Horizonte, implemented the BSS2 and methodologies are investigated for characterizing the beta radiation fields by determining the field homogeneity, the accuracy and uncertainties in the absorbed dose in air measurements. In this work, a methodology to be used for verifying the metrological coherence among beta radiation fields in standard systems was investigated; an extrapolation chamber and radiochromic films were used and measurements were done in terms of absorbed dose in air. The reliability of both the extrapolation chamber and the radiochromic film was confirmed and their calibrations were done in the LCD/CDTN in {sup 90}Sr/{sup 90}Y, {sup 85}Kr and {sup 147}Pm beta radiation fields. The angular coefficients of the extrapolation curves were determined with the chamber; the field mapping and homogeneity were obtained from dose profiles and isodose with the radiochromic films. A preliminary comparison between the LCD/CDTN and the Instrument Calibration Laboratory of the Nuclear and Energy Research Institute / Sao Paulo (LCI/IPEN) was carried out. Results with the extrapolation chamber measurements showed in terms of absorbed dose in air rates showed differences between both laboratories up to de -I % e 3%, for {sup 90}Sr/{sup 90}Y, {sup 85}Kr and {sup 147}Pm beta radiation fields, respectively. Results with the EBT radiochromic films for 0.1, 0.3 and 0.15 Gy absorbed dose in air, for the same beta radiation fields, showed differences up to 3%, -9% and -53%. The beta radiation field mappings with radiochromic films in both BSS2 showed that some of them were not geometrically aligned. (author)

Castillo, Jhonny Antonio Benavente

2011-07-01

382

Production and characterization of TI/PbO2 electrodes by a thermal-electrochemical method  

Directory of Open Access Journals (Sweden)

Full Text Available Looking for electrodes with a high overpotential for the oxygen evolution reaction (OER, useful for the oxidation of organic pollutants, Ti/PbO2 electrodes were prepared by a thermal-electrochemical method and their performance was compared with that of electrodeposited electrodes. The open-circuit potential for these electrodes in 0.5 mol L-1 H2SO4 presented quite stable similar values. X-ray diffraction analyses showed the thermal-electrochemical oxide to be a mixture of ort-PbO, tetr-PbO and ort-PbO2. On the other hand, the electrodes obtained by electrodeposition were in the tetr-PbO2 form. Analyses by scanning electron microscopy showed that the basic morphology of the thermal-electrochemical PbO2 is determined in the thermal step, being quite distinct from that of the electrodeposited electrodes. Polarization curves in 0.5 mol L-1 H2SO4 showed that in the case of the thermal-electrochemical PbO2 electrodes the OER was shifted to more positive potentials. However, the values of the Tafel slopes, quite high, indicate that passivating films were possibly formed on the Ti substrates, which could eventually explain the somewhat low current values for OER.

Laurindo Edison A.

2000-01-01

383

An Individual-based Model for Extrapolating Standard Toxicity Test Data into Population-level Adverse Outcomes in the Fathead Minnow  

Science.gov (United States)

While environmental toxicity testing typically focuses on organism-level endpoints such as mortality, growth, and reproduction, risk assessment guidelines specify protection goals at the level of the population and above. One method of linking these different levels of biological...

384

Track parameter propagation through the application of a new adaptive Runge-Kutta-Nyström method in the ATLAS experiment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we study several fixed step and adaptive Runge-Kutta methods suitable for transporting track parameters through an inhomogeneous magnetic field. Moreover, we present a new adaptive Runge-Kutta-Nyström method which estimates the local error of the extrapolation without introducing extra stages to the original Runge-Kutta-Nyström method. Furthermore, these methods are compared for propagation accuracy and computing cost efficiency in the simultaneous track and error propagation ...

Lund, Espen; Bugge, Lars; Gavrilenko, Igor; Strandlie, Are

2009-01-01

385

Comparative study among calibration methods of clinical applicators of beta radiation  

International Nuclear Information System (INIS)

90Sr+90Y clinical applicators are instruments used in brachytherapy procedures and they have to be periodically calibrated, according to international standards and recommendations. In this work, four calibration methods of dermatological and ophthalmic applicators were studied, comparing the results with those given by the calibration certificates of the manufacturers. The methods included the use of the standard applicator of the Calibration Laboratory (LCI), calibrated by the National Institute of Standards and Technology; an Amersham applicator (LCI) as reference; a mini-extrapolation chamber developed at LCI as an absolute standard; and thermoluminescent dosimetry. The mini-extrapolation chamber and a PTW commercial extrapolation chamber were studied in relation to their performance through quality control tests of their response, as leakage current, repeatability and reproducibility. The distribution of the depth dose in water, that presents high importance in dosimetry of clinical applicators, was determined using the mini extrapolation chamber and the thermoluminescent dosimeters. The results obtained were considered satisfactory for the both cases, and comparable to the data of the IAEA (2002) standard. Furthermore, a dosimetry postal kit was developed for the calibration of clinical applicators using the thermoluminescent technique, to be sent to clinics and hospitals, without the need of the transport of the sources to IPEN for calibration. (author)

386

Copper complex N(4)-ortho-toluyl-2-acetylpyridine thiosemicarbazone - ({sup 64}Cu)(H2Ac4oT)Cl - internal dosimetry: animal model and human extrapolation  

Energy Technology Data Exchange (ETDEWEB)

Thiosemicarbazones have attracted great pharmacological interest because of their biological properties, such as cytotoxic activity against multiple strains of human tumors. Due to the excellent properties of {sup 64}Cu, the copper complex N(4)-ortho-toluyl-2-acetylpyridine thiosemicarbazone (({sup 64}Cu)(H2Ac4oT)Cl) was developed for tumor detection by positron emission tomography. The radiopharmaceuticals were produced in the nuclear reactor TRIGA-IPR-R1 from CDTN. At the present work, ({sup 64}Cu)(H2Ac4oT)Cl biokinetic data (evaluated in mice bearing Ehrlich tumor) were treated by MIRD formalism to perform Internal Dosimetry studies. Doses in several organs of mice were determinate, as well as in implanted tumor, for ({sup 64}Cu)(H2Ac4oT)Cl. Doses results obtained for animal model were extrapolated to humans assuming a similar concentration ratio among various tissues between mouse and human. In the extrapolation, it was used human organ masses from Cristy/Eckerman phantom. Both penetrating and non-penetrating radiation from {sup 64}Cu in the tissue were considered in dose calculations. (author)

Rodrigues, Josianne L.; Silva, Paulo R.O.; Santos, Raquel G.; Ferreira, Andrea V., E-mail: jlr@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

387

Copper corrosion inhibition in O{sub 2}-saturated H{sub 2}SO{sub 4} solutions  

Energy Technology Data Exchange (ETDEWEB)

Corrosion inhibition of copper in O{sub 2}-saturated 0.50 M H{sub 2}SO{sub 4} solutions by four selected amino acids, namely glycine (Gly), alanine (Ala), valine (Val), or tyrosine (Tyr), was studied using Tafel polarization, linear polarization, impedance, and electrochemical frequency modulation (EFM) at 30 deg. C. Protection efficiencies of almost 98% and 91% were obtained with 50 mM Tyr and Gly, respectively. On the other hand, Ala and Val reached only about 75%. Corrosion rates determined by the Tafel extrapolation method were in good agreement with those obtained by EFM and an independent chemical (i.e., non-electrochemical) method. The chemical method of confirmation of the corrosion rates involved determination of the dissolved Cu{sup 2+}, using ICP-AES (inductively coupled plasma atomic emission spectrometry) method of chemical analysis. Nyquist plots exhibited a high frequency depressed semicircle followed by a straight line portion (Warburg diffusion tail) in the low-frequency region. The impedance data were interpreted according to two suitable equivalent circuits. The kinetics of dissolved O{sub 2} reduction and hydrogen evolution reactions on copper surface were also studied in O{sub 2}-saturated 0.50 M H{sub 2}SO{sub 4} solutions using polarization measurements combined with the rotating disc electrode (RDE). The Koutecky-Levich plot indicated that the dissolved O{sub 2} reduction at the copper electrode was an apparent 4-electron process.

Amin, Mohammed A. [Materials and Corrosion Lab (MCL), Department of Chemistry, Faculty of Science, Taif University, 888 Hawiya, KSA (Egypt); Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, Cairo (Egypt)], E-mail: maaismail@yahoo.com; Khaled, K.F. [Materials and Corrosion Lab (MCL), Department of Chemistry, Faculty of Science, Taif University, 888 Hawiya, KSA (Egypt); Electrochemistry Research Laboratory, Faculty of Education, Ain Shams University, Roxy, Cairo (Egypt)

2010-04-15

388

Summary of existing uncertainty methods  

International Nuclear Information System (INIS)

A summary of existing and most used uncertainty methods is presented, and the main features are compared. One of these methods is the order statistics method based on Wilks' formula. It is applied in safety research as well as in licensing. This method has been first proposed by GRS for use in deterministic safety analysis, and is now used by many organisations world-wide. Its advantage is that the number of potential uncertain input and output parameters is not limited to a small number. Such a limitation was necessary for the first demonstration of the Code Scaling Applicability Uncertainty Method (CSAU) by the United States Regulatory Commission (USNRC). They did not apply Wilks' formula in their statistical method propagating input uncertainties to obtain the uncertainty of a single output variable, like peak cladding temperature. A Phenomena Identification and Ranking Table (PIRT) was set up in order to limit the number of uncertain input parameters, and consequently, the number of calculations to be performed. Another purpose of such a PIRT process is to identify the most important physical phenomena which a computer code should be suitable to calculate. The validation of the code should be focused on the identified phenomena. Response surfaces are used in some applications replacing the computer code for performing a high number of calculations. The second well known uncertainty method is the Uncertainty Methodology Based on Accuracy Extrapolation (UMAE) and the follow-up method 'Code with the Capability of Internal Assessment of Uncertainty (CIAU)' developed by the University Pisa. Unlike the statistical approaches, the CIAU does compare experimental data with calculation results. It does not consider uncertain input parameters. Therefore, the CIAU is highly dependent on the experimental database. The accuracy gained from the comparison between experimental data and calculated results are extrapolated to obtain the uncertainty of the system code predictions for a nuclear power plant. A high effort is needed to provide the data base for deviations between experiment and calculation results in CIAU. That time and resource consuming process has been performed only by University of Pisa for the codes CATHARE and RELAP5 up to now. The data base is available only there. That is the reason why this method is only used by University of Pisa. (author)

389

The direct current method for measuring charged membrane conductance  

International Nuclear Information System (INIS)

This paper deals with a method for measuring electrical resistance in charged membranes. The method is based on the application of a step change in direct current and on the analysis of the potential transient subsequent to the application of the current step. Membrane electrical resistance was determined by an extrapolation to zero time of potential differences measured after the current step. Experimental results obtained with commercial ion-exchange membranes were in good agreement with those computed from the Fick equation. The method developed gives more accurate values with a standard deviation lower than traditional techniques and allows the resistance of an asymmetrical membrane to be determined in both current directions. (orig.)

390

The TDCR method for activity standardization in liquid scintillation counting  

International Nuclear Information System (INIS)

A new method for radioactivity standardization in liquid scintillation counting was described. In the method a triple to double coincidence ratio was taken for a reference quantity of efficiency change and the coincidence counting was extrapolated to the value of TDCR = 1, thus may lead to an approximate value for the sample activity directly. This paper shows the principle of the method, the efficiency calculation and the estimate of the uncertainty. The measured result for tritiated water coincides with the nominal value of the NBS standard within an uncertainty of +- 0.63%

391

Express-method for evaluating residual life of structural members under creep  

International Nuclear Information System (INIS)

An approximate method is suggested to estimate residual material life for members in creep. The method is based on comparison of extrapolated curves of the long-term material strength in the initial state and after operating time. An example is given to illustrate the determination of residual life for steel 13CrMo44 of the steam lines after 125 ths h of service

392

Comparisons of methods for measuring yield stresses in potato puree: Effect of temperature and freezing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Seven methods for determining yield stress of concentrated suspensions were applied to fresh and frozen/thawed natural and commercial purees at different temperatures, and results were compared. Since potato puree was consistent with Herschel-Bulkley flow behaviour, yield stress was more reliably determined by extrapolation of the flow curves assuming Herschel-Bulkley model than Bingham and Casson models. Methods for determining yield stress by dynamic rheological tests were tedious and are n...

Canet, Wenceslao; Alvarez, M. Dolores; Ferna?ndez, Cristina; Luna, Pilar

2005-01-01

393

Loomemajandus vajab õitsenguks soosivat keskkonda / Külliki Tafel-Viia, Silja Lassur, Andres Viia ; intervjueerinud Tiina Saar  

Index Scriptorium Estoniae

TLÜ Eesti Tuleviku-uuringute Instituudi teadurid vastavad küsimustele, mis puudutavad tavalise ja loovmajanduse erinevusi, Eesti loomemajanduse positsiooni võrreldes teiste riikidega, loomemajandusega seotud valdkondi, loomeettevõtlust ja loomeettevõtteid, loomemajanduses edukas olemiseks vajalikke ressursse ning loomeettevõtete erinevusi võrreldes teiste ettevõtetega

Tafel-Viia, Külliki

2009-01-01

394

Multilayer graphene stacks grown by different methods-thickness measurements by X-ray diffraction, Raman spectroscopy and optical transmission  

International Nuclear Information System (INIS)

X-ray diffraction, Raman spectroscopy and Optical absorption estimates of the thickness of graphene multi layer stacks (number of graphene layers) are presented for three different growth techniques. The objective of this work was focused on comparison and reconciliation of the two already widely used methods for thickness estimates (Raman and Absorption) with the calibration of the X-ray method as far as Scherer constant K is concerned and X-ray based Wagner-Aqua extrapolation method

395

Full scale assessment of pansharpening methods and data products  

Science.gov (United States)

Quality assessment of pansharpened images is traditionally carried out either at degraded spatial scale by checking the synthesis property ofWald's protocol or at the full spatial scale by separately checking the spectral and spatial consistencies. The spatial distortion of the QNR protocol and the spectral distortion of Khan's protocol may be combined into a unique quality index, referred to as hybrid QNR (HQNR), that is calculated at full scale. Alternatively, multiscale measurements of indices requiring a reference, like SAM, ERGAS and Q4, may be extrapolated to yield a quality measurement at the full scale of the fusion product, where a reference does not exist. Experiments on simulated P?eiades data, of which reference originals at full scale are available, highlight that quadratic polynomials having three-point support, i.e. fitting three measurements at as many progressively doubled scales, are adequate. Q4 is more suitable for extrapolation than ERGAS and SAM. The Q4 value predicted from multiscale measurements and the Q4 value measured at full scale thanks to the reference original, differ by very few percents for six different state-of-the-art methods that have been compared. HQNR is substantially comparable to the extrapolated Q4.

Aiazzi, B.; Alparone, L.; Baronti, S.; Carlà, R.; Garzelli, A.; Santurri, L.

2014-10-01

396

Development of a multi-electrode extrapolation chamber as a prototype of a primary standard for the realization of the unit of the absorbed dose to water for beta brachytherapy sources  

CERN Document Server

The prototype of a primary standard has been developed, built and tested, which enables the realization of the unit of the absorbed dose to water for beta brachytherapy sources. In the course of the development of the prototype, the recommendations of the American Association of Physicists in Medicine (AAPM) Task Group 60 (TG60) and the Deutsche Gesellschaft fuer Medizinische Physik (DGMP) Arbeitskreis 18 (AK18) were taken into account. The prototype is based on a new multi-electrode extrapolation chamber (MEC) which meets, in particular, the requirements on high spatial resolution and small uncertainty. The central part of the MEC is a segmented collecting electrode which was manufactured in the clean room center of PTB by means of electron beam lithography on a wafer. A precise displacement device consisting of three piezoelectric macrotranslators has been incorporated to move the wafer collecting electrode against the entrance window. For adjustment of the wafer collecting electrode parallel to the entranc...

Bambynek, M

2002-01-01

397

Molecular polarizability of organic molecules and their complexes. Communication LIV. Molar volumes of polyaryl organoelement compounds in solutions, extrapolated to infinite dilution, and steric structure of the molecules  

International Nuclear Information System (INIS)

Molar volumes in various solvents were determined for organic derivatives of silicon, phosphorus, arsenic, sulfur, and tellurium, containing aryl nuclei capable to internal rotation about single bonds between them and bridging groups. Additive analysis of the molar volumes of these compounds showed that the aryl nuclei are acoplanar with respect to the bridging groups. Most probable is a conrotatory mutual orientation of the aromatic rings. Molar volumes were also determined for a series of compounds with two bridging groups, which can serve as models of an extreme case of mutual proximity of aryl ring planes in diaryl systems with one bridging group. A possibility for considerably simplifying the methods for determination of dipole moments and Kerr constants for compounds whose molar volumes can be calculated by our developed additive scheme is demonstrated

398

In vivo doses of butadiene epoxides as estimated from in vitro enzyme kinetics by using cob(I)alamin and measured hemoglobin adducts: An inter-species extrapolation approach.  

Science.gov (United States)

1,3-Butadiene (BD) is a rodent and human carcinogen. In the cancer tests, mice have been much more susceptible than rats with regard to BD-induced carcinogenicity. The species-differences are dependent on metabolic formation/disappearance of the genotoxic BD epoxy-metabolites that lead to variations in the respective in vivo doses, i.e. "area under the concentration-time curve" (AUC). Differences in AUC of the most gentoxic BD epoxy-metabolite, diepoxybutane (DEB), are considered important with regard to cancer susceptibility. The present work describes: the application of cob(I)alamin for accurate measurements of in vitro enzyme kinetic parameters associated with BD epoxy-metabolites in human, mouse and rat; the use of published data on hemoglobin (Hb) adduct levels of BD epoxides from BD exposure studies on the three species to calculate the corresponding AUCs in blood; and a parallelogram approach for extrapolation of AUC of DEB based on the in vitro metabolism studies and adduct data from in vivo measurements. The predicted value of AUC of DEB for humans from the parallelogram approach was 0.078nM·h for 1ppm·h of BD exposure compared to 0.023nM·h/ppm·h as calculated from Hb adduct levels observed in occupational exposure. The corresponding values in nM·h/ppm·h were for mice 41 vs. 38 and for rats 1.26 vs. 1.37 from the parallelogram approach vs. experimental exposures, respectively, showing a good agreement. This quantitative inter-species extrapolation approach will be further explored for the clarification of metabolic rates/pharmacokinetics and the AUC of other genotoxic electrophilic compounds/metabolites, and has a potential to reduce and refine animal experiments. PMID:25448046

Motwani, Hitesh V; Törnqvist, Margareta

2014-11-01

399

Development of a multi-electrode extrapolation chamber as a prototype of a primary standard for the realization of the unit of the absorbed dose to water for beta brachytherapy sources  

Energy Technology Data Exchange (ETDEWEB)

The prototype of a primary standard has been developed, built and tested, which enables the realization of the unit of the absorbed dose to water for beta brachytherapy sources. In the course of the development of the prototype, the recommendations of the American Association of Physicists in Medicine (AAPM) Task Group 60 (TG60) and the Deutsche Gesellschaft fuer Medizinische Physik (DGMP) Arbeitskreis 18 (AK18) were taken into account. The prototype is based on a new multi-electrode extrapolation chamber (MEC) which meets, in particular, the requirements on high spatial resolution and small uncertainty. The central part of the MEC is a segmented collecting electrode which was manufactured in the clean room center of PTB by means of electron beam lithography on a wafer. A precise displacement device consisting of three piezoelectric macrotranslators has been incorporated to move the wafer collecting electrode against the entrance window. For adjustment of the wafer collecting electrode parallel to the entrance foil, an electro-mechanical adjustment system based on a capacitance bridge circuit has been developed. The MEC allows a three-dimensional dose distribution to be measured with high spatial resolution, without having to fall back on an additional relative dosimetry system. All components of the MEC were separately investigated for suitability. The extrapolation chamber measurements on a plane beta source proved the suitability of the MEC as a primary standard. With sizes of collector electrodes as small as 1 mmx1 mm, calibrations were performed with a relative combined standard uncertainty of 3.8%. The reproducibility of the MEC amounted to 1.5%, with k=1.

Bambynek, M. E-mail: markus.bambynek@ptb.de

2002-10-11

400

Accurate double many-body expansion potential energy surface by extrapolation to the complete basis set limit and dynamics calculations for ground state of NH2.  

Science.gov (United States)

An accurate single-sheeted double many-body expansion potential energy surface is reported for the title system. A switching function formalism has been used to warrant the correct behavior at the H2(X1?g+)+N(2D) and NH?(X3?-)+H(2S) dissociation channels involving nitrogen in the ground N(4S) and first excited N(2D) states. The topographical features of the novel global potential energy surface are examined in detail, and found to be in good agreement with those calculated directly from the raw ab initio energies, as well as previous calculations available in the literature. The novel surface can be using to treat well the Renner-Teller degeneracy of the 12A? and 12A' states of NH?2. Such a work can both be recommended for dynamics studies of the N(2D)+H2 reaction and as building blocks for constructing the double many-body expansion potential energy surface of larger nitrogen/hydrogen-containing systems. In turn, a test theoretical study of the reaction N(2D)+H2(X1?g+)(?=0,j=0)?NH?(X3?-)+H(2S) has been carried out with the method of quantum wave packet on the new potential energy surface. Reaction probabilities, integral cross sections, and differential cross sections have been calculated. Threshold exists because of the energy barrier (68.5 meV) along the minimum energy path. On the curve of reaction probability for total angular momentum J?=?0, there are two sharp peaks just above threshold. The value of integral cross section increases quickly from zero to maximum with the increase of collision energy, and then stays stable with small oscillations. The differential cross section result shows that the reaction is a typical forward and backward scatter in agreement with experimental measurement result. PMID:23666848

Li, Yongqing; Yuan, Jiuchuang; Chen, Maodu; Ma, Fengcai; Sun, Mengtao

2013-07-15

 
 
 
 
401

Developing a Theory of Digitally-Enabled Trial-Based Problem Solving through Simulation Methods: The Case of Direct-Response Marketing  

Science.gov (United States)

In turbulent business environments, change is rapid, continuous, and unpredictable. Turbulence undermines those adaptive problem solving methods that generate solutions by extrapolating from what worked (or did not work) in the past. To cope with this challenge, organizations utilize trial-based problem solving (TBPS) approaches in which they…

Clark, Joseph Warren

2012-01-01

402

Preparation of ultrafine tungsten wire via electrochemical method in an ionic liquid  

International Nuclear Information System (INIS)

Highlights: ? The method of electrochemical corrosion is used to prepare ultra-fine tungsten wire less than 10 ?m in diameter. ? Ionic liquid as a non-aqueous electrolyte was used in electrochemical corrosion experiments. ? The situation of anode polarization was different from the usual situation. ? Diameter of tungsten wire has been cut down to 8.5 ?m uniformly under the optimized electric potential. - Abstract: Ultrafine tungsten wire less than 10 ?m in diameter is often used as wire array load applied in Inertial Confinement Fusion (ICF) physical experiments. In order to obtain a higher yield of X-ray, both initial radius and line quality of metal wire were required to be of high quality simultaneously. This paper has studied the electrochemical method to corrode tungsten wires uniformly in an ionic liquid electrolyte containing 1 wt% sodium hydroxide. A three electrode system composed of a tungsten anode electrode, a stainless steel cathode and a saturated calomel electrode as a reference electrode, was used in the electrochemical experiments. Liner sweep voltammetry (LSV) and Tafel experiments were used to investigate the electrochemical behaviors of tungsten wires in ionic liquid and aqueous solution. Based on scanning electron microscope (SEM) observation, the morphologies of tungsten wire surface with uniform corrosion under different applied voltages have been demonstrated. X-ray diffraction (XRD) methods were employed to track the evolution of thed to track the evolution of the crystal structure before and after corrosions, and there is an obvious difference in peak intensities. The ultrafine tungsten wire with a uniform diameter of 8.5 ?m was obtained under the optimized electric potential (2.5 V) applied for decreasing diameter at 30 °C.

403

Interpolation methods and their use in radiation protection  

International Nuclear Information System (INIS)

The presentation summarizes results of using various interpolation methods for getting spatial data from point measurements. These methods were evaluated within the State Office for Nuclear Safety (SONS) Science and Research Project No. 2/2008 'Methods and Measures to Limit Generation and Liquidation of Consequences of Radioactive Matter Misuse by Terrorists'. Several field tests in which the short life-time radioactive matter was released by explosion were realized and the measured data were processed. The essential goal is to find the most realistic method for radiation events assessment. Within the research project, three methods were used: Multilevel B-Spline, Triangulation and Kriging, using freely available SAGA GIS software. The best solution for this sort of radiation events appears to be the Multilevel B-Spline method. It is quick and produces good quality output data comparable with the much slower Kriging method and allows extrapolation in contrast to Triangulation. (author)

404

Desplazamiento del anillo tricuspídeo en niños normales determinado mediante extrapolación de programa ecocardiográfico / Tricuspid annular displacement in normal children measured by an extrapolated echocardiographic program  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish Introducción: la excursión sistólica del plano lateral del anillo tricuspídeo (TAPSE) es un parámetro útil en la evaluación de la función del ventrículo derecho en pacientes pediátricos. Objetivos: mostrar los valores normales del TAPSE en niños cubanos según grupos etarios, y describir su relación [...] con la edad, gasto del ventrículo izquierdo, tiempo de aceleración pulmonar y la fracción de eyección del ventrículo izquierdo. Métodos: se realizó un estudio prospectivo en el que se incluyeron 102 niños normales, a cuya medición del TAPSE se les realizó adaptando el programa para la mensuración de la distancia entre el punto E y el septum interventricular. Resultados: el TAPSE medio fue de 19,4 mm (DS±6) con valores medios en la primera semana de 9,5 mm hasta 21,2 a los 5 años y 24,1 en niños mayores. Se encontró correlación positiva significativa entre el TAPSE y la edad (r= 0,679) descrita por la ecuación TAPSE= 13,2787 + 5,2354 log (X). Se mostraron los valores del TAPSE en 5 grupos de edades. Se encontró también una correlación significativa entre el TAPSE, el tiempo de aceleración pulmonar y el gasto sistólico del ventrículo izquierdo. Conclusiones: existen 5 grupos etarios bien definidos, los mayores cambios del TAPSE se presentan antes de los 5 años de edad, y se encontró una relación logarítmica entre el TAPSE, la edad y el tiempo de aceleración pulmonar. Se recomienda el programa utilizado como alternativa en la medición del TAPSE. Abstract in english Introduction: the tricuspid annular plane systolic excursion (TAPSE) is a useful parameter to evaluate the right ventricular function in pediatric patients. Objectives: to show the normal values of TAPSE in Cuban children by age groups, and to describe their relationship with the age, the left ventr [...] icular output, the pulmonary acceleration time and the ejection fraction of the left ventricle. Methods: a prospective study included 102 normal children to whom TAPSE was measured by adapting the program for distance mensuration between point E and the interventricular septum. Results: average TAPSE was 19.4 mm (DS±6) with mean values equal to 9.5 mm in the first week up to 21.2 mm at 5 years and 24.1 in older children. There was significant positive correlation between TAPSE figures and age (r= 0.679) described in equation TAPSE= 13.2787 + 5.2354 log (X). The TAPSE values were presented in five age groups. It was also found that there was significant correlation among TAPSE, pulmonary acceleration time and systolic output of the left ventricle. Conclusions: there exist five well-defined age groups, the major changes occur before 5 years of age and log relation was found among TAPSE, age and pulmonary acceleration time. The used program is recommended as an alternative to measure TAPSE.

Francisco Javier, Ozores Suárez.

2013-09-01

405

Mechanical Properties and Corrosion Behavior of Low Carbon Steel Weldments  

Directory of Open Access Journals (Sweden)

Full Text Available This research involves studying the mechanical properties and corrosion behavior of ?low carbon steel? (0.077wt% C before and after welding using Arc, MIG and TIG welding. The mechanical properties include testing of microhardness, tensile strength, the results indicate that microhardness of TIG, MIG welding is more than arc welding, while tensile strength in arc welding more than TIG and MIG.The corrosion behavior of low carbon weldments was performed by potentiostat at scan rate 3mV.sec-1 in 3.5% NaCl to show the polarization resistance and calculate the corrosion rate from data of linear polarization by ?Tafel extrapolation method?. The results indicate that the TIG welding increase the corrosion current density and anodic Tafel slop, while decrease the polarization resistance compared with unwelded low carbon steel. Cyclic polarization were measured to show resistance of specimens to pitting corrosion and to calculate the forward and reveres potentials. The results show shifting the forward, reverse and pitting potentials toward active direction for weldments samples compared with unwelded sample.

Mohamed Mahdy

2013-01-01

406

Droplet models as approximations to the extended Thomas-Fermi method  

International Nuclear Information System (INIS)

The conventional droplet model and the ''finite-range'' droplet model of Moeller et al. are compared with the extended Thomas-Fermi method (ETF) in order to test how reliably these models extrapolate from the region of known nuclei out to the neutron-drip line. We proceed by fitting each of the two droplet models to the binding energies of a large number of nuclei in the known region, calculated by the ETF method. On extrapolating to the neutron-drip line we find that the droplet models can disagree by as much as 10-15 MeV with ETF. However, a dramatic improvement results if higher-order surface-symmetry terms are included in the droplet model; their effect is to ''soften'' the neutron skin as the neutron excess grows. (orig.)

407

Perturbation method for experimental determination of neutron spatial distribution in the reactor cell  

International Nuclear Information System (INIS)

The method is based on perturbation of the reactor cell from a few up to few tens of percent. Measurements were performed for square lattice calls of zero power reactors Anna, NORA and RB, with metal uranium and uranium oxide fuel elements, water, heavy water and graphite moderators. Character and functional dependence of perturbations were obtained from the experimental results. Zero perturbation was determined by extrapolation thus obtaining the real physical neutron flux distribution in the reactor cell. Simple diffusion theory for partial plate cell perturbation was developed for verification of the perturbation method. The results of these calculation proved that introducing the perturbation sample in the fuel results in flattening the thermal neutron density dependent on the amplitude of the applied perturbation. Extrapolation applied for perturbed distributions was found to be justified

408

Wavefield reconstruction methods for reverse time migration  

International Nuclear Information System (INIS)

During pre-stack reverse time migration (RTM), the shot and receiver wavefields are extrapolated separately along opposite directions, which means the shot wavefield should be saved and it is a bottleneck of RTM. The random boundary condition (RBC) method could be used to reconstruct the shot wavefield to solve this problem. The disadvantage of RBC is that the free surface boundary condition (FSBC) should be used because the RBC at the surface boundary will induce severe noise all through the imaging profile. The use of FSBC is also harmful because the reflections from the surface will generate imaging illusions. In this paper, we use two different boundary conditions, which use an absorbing boundary condition on the upper boundary, to perfectly reconstruct the shot wavefield. The new schemes could solve the free surface boundary problem and would not demand much memory. The numerical examples prove the efficiency of these methods. (paper)

409

A simple way of estimation of the mitosis duration by the radiation method  

International Nuclear Information System (INIS)

In the curve of mitotic index drop of cell population immediately after irradiation there is a linear section the extrapolation of which to horizontal line of the mitotic index initial level and to ''time'' abscissa axis permits to separate the time interval equal to average mitosis duration. The given parameter estimation for fibroblasts culture by the above method coincided with its value calculated by mitotic index and time of doubling cell number determined experimentally

410

First criticality prediction of the HTTR by 1/M interposition method  

International Nuclear Information System (INIS)

The HTTR's first criticality was achieved in an annular core configuration . It was difficult to predict the first criticality by extrapolation of 1/M. The number of fuel columns at the first criticality was predicted comparing the measured and calculated values of 1/M. The calculated values were obtained by the calculation which achieve the criticality at arbitrary number of fuel loaded core. The number of fuel column to achieve the first criticality was evaluated precisely by the method. (author)

411

A newly synthesized glycine derivative to control uniform and pitting corrosion processes of Al induced by SCN{sup -} anions - Chemical, electrochemical and morphological studies  

Energy Technology Data Exchange (ETDEWEB)

A newly synthesized glycine derivative (termed GlyD), 2-(4-(dimethylamino)benzylamino)acetic acid hydrochloride, was used to inhibit uniform and pitting corrosion processes of Al in 0.50 M KSCN solutions (pH 6.8) at 25 {sup o}C. For uniform corrosion inhibition study, Tafel extrapolation, linear polarization resistance and impedance methods were used, complemented with SEM examinations. An independent method of chemical analysis, namely ICP-AES (inductively coupled plasma atomic emission spectrometry) was also used to test validity of corrosion rate measured by Tafel extrapolation method. GlyD inhibited uniform corrosion, even at low concentrations, reaching a value of inhibition efficiency up to 97% at a concentration of 5 x 10{sup -3} M. Results obtained from the different corrosion evaluation techniques were in good agreement. This new synthesized glycine derivative was also used to control pit nucleation and growth on the pitted Al surface based on cyclic polarization, potentiostatic and galvanostatic measurements. The pitting potential (E{sub pit}) and the repassivation potential (E{sub rp}) increased by the addition of GlyD. Thus GlyD suppressed pit nucleation and propagation. Nucleation of pit was found to take place after an incubation time (t{sub i}). The rate of pit nucleation and growth decreased with increase in inhibitor concentration. Morphology of pitting was also studied as a function of the applied anodic potential and solution temperature. Cross-sectional view of pitted surface revealed the formation of large distorted hemispherical and narrow deep pits. GlyD was much better than Gly in controlling uniform and pitting corrosion processes of Al in these solutions.

Amin, Mohammed A., E-mail: maaismail@yahoo.co [Department of Chemistry, Faculty of Science, Ain Shams University, 11566 Abbassia, Cairo (Egypt); Materials and Corrosion Lab (MCL), Chemistry Department, Faculty of Science, Taif University, 888 Hawiya (Saudi Arabia)

2010-10-15

412

Dissolution of chromium in sulfuric acid  

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Full Text Available By combining electrochemical corrosion rate measurements and spectrophotometric analysis of the electrolyte it was shown that at room temperature chromium dissolves in deaerated 0.1 M Na2SO4 + H2SO4 (pH 1 solution as Cr(II and Cr(III ions in he ratio Cr(II : Cr(III @ 7 : 1. This process was stable over 4 h without any detectable change. The total corrosion rate of chromium calculated from the analytical data is about 12 times higher, than that determined electrochemically by cathodic Tafel line extrapolation to the corrosion potential. This finding was confirmed by applying the weight-loss method for the determination of the corrosion rate. This enormous difference between these experimentally determined corrosion rates can be explained by the rather fast, ?anomalous? dissolution process proposed by Kolotyrkin and coworkers (chemical reaction of Cr with H2O molecules occurring simultaneously with the electrochemical corrosion process.

J. P. POPIC

2002-11-01

413

Electrochemical Corrosion Behavior of TiN-Coated Biomedical Ti-Cu Alloy Foam in Fluoride Containing Artificial Saliva  

Science.gov (United States)

Highly porous Ti-Cu alloy foams were produced by powder metallurgy method for implant applications. Ti-Cu alloys were prepared with 3, 5, 7, and 10 wt pct Cu contents in order to determine optimum Cu addition. Cu addition enhances sinterability, and the Ti-Cu compacts were sintered at lower temperatures and times than pure Ti. Specimens were coated with a TiN film to enhance wear and corrosion resistance. Sintered specimens were precipitation hardened (aged) in order to increase mechanical properties. Corrosion properties of foams were examined by electrochemical techniques, such as potentiodynamic polarization, cyclic polarization, Tafel extrapolation, linear polarization resistance, and open-circuit potential measurement. Effect of Cu content, TiN coating, pH, and fluoride content of artificial saliva on electrochemical corrosion behavior of specimens was investigated.

Mutlu, Ilven

2014-07-01

414

A Study of Electrochemical Protection of Carbon Steels in Sulfuric Acid Solutions - Electrochemical Protection Diagrams of Metals (1) -  

International Nuclear Information System (INIS)

Electrochemical protection of carbon steels was studied in sulfuric acid solutions. The main results obtained are as follows: 1) Electrochemical protection diagrams of carbon steels in sulfuric acid solutions can be drawn with the data from Jeon's determination method of the optimum cathodic protection potential, the Tafel extrapolation and the characteristics of anodic polarization curves, and the diagram also represent various practical protection data. 2) Corrosion rates of carbon steels in the more concentration than 45% solutions are very low because they are on sulfaction or passivation in the solution, but the rates in the less concentration than the solutions are very high since they are on activation. 3) SS 41 steel is suitable in the more concentration than 45% solutions but SM 50 steel is relatively good in the less concentration than the solutions from the economical view

415

Wear and Corrosion Behavior of CoNiCrAlY Bond Coats  

Science.gov (United States)

The present study focusses on the wear and microstructural properties of CoNiCrAlY coatings fabricated on AISI 316L stainless steel substrate by using the (HVOF) and (CGDS) methods. A triobiological test was performed on the samples in order to understand the wear behaviour of thermally sprayed coatings. The microstructures of as-sprayed and worn out coatings were investigated by scanning electron microscopy. Coating hardness measurements were performed with nanoindentation. HVOF coating revealed lower hardness value in comparison with CGDS. Studies depicted better wear resistance of the CGDS sprayed with He, when compared to CGDS N2 and HVOF processing. Potentiodynamic polarization curves and tafel extrapolation experiments were carried at 7.5 pH value using 3.5 % NaCl as an electrolyte. Electrochemical studies depicted better corrosion resistance of the He processed coating when compared to N2 and HVOF processing.

Rathod, W. S.; Khanna, A. S.; Rathod, R. C.; Sapate, S. G.

2014-07-01

416

Effect of small addition of aluminum on electrochemical corrosion behavior of magnesium-calcium sacrificial anode in underground environment  

International Nuclear Information System (INIS)

The effect of small addition of Al on the electrochemical performances was investigated by open circuit potential and Tafel Extrapolation method. The results show that open circuit potential reveals as-cast Mg containing Ca alloys with minor content of Al maintained highly negative potential with the range of -1.68 to -1.63 VSCE in comparison to both pure Mg (-1.60VSCE) and commercial high potential Mg content. Corrosion rate for the as-cast samples remains higher (30-17 mpy) than pure Mg (3 mpy) and commercial high potential Mg anode (14 mpy). The increasing small content of Al results in the reduction of corrosion rate significantly. Therefore, it proves that the performance of Mg containing Ca alloy is strongly influenced by the concentration of Al. (author)

417

The present state of research into plasma heating and injection methods  

International Nuclear Information System (INIS)

The advantages and disadvantages recognized by the Advisory Group on Heating and injection for twelve plasma heating and injection methods currently