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1

Scale Reliability, Cronbach's Coefficient Alpha, and Violations of Essential Tau-Equivalence with Fixed Congeneric Components.  

ERIC Educational Resources Information Center

The population discrepancy between Cronbach's Coefficient Alpha (L. Cronbach, 1951) and scale reliability with fixed congeneric measure, uncorrelated errors, and sampling of subjects was studied. The difference is expressed in terms of the individual component violations of the assumption of equal tau-equivalence that is necessary and sufficient…

Raykov, Tenko

1997-01-01

2

Minimum Sample Size for Cronbach's Coefficient Alpha: A Monte-Carlo Study  

ERIC Educational Resources Information Center

|The coefficient alpha is the most widely used measure of internal consistency for composite scores in the educational and psychological studies. However, due to the difficulties of data gathering in psychometric studies, the minimum sample size for the sample coefficient alpha has been frequently debated. There are various suggested minimum…

Yurdugul, Halil

2008-01-01

3

The Impact of Outliers on Cronbach's Coefficient Alpha Estimate of Reliability: Ordinal/Rating Scale Item Responses  

ERIC Educational Resources Information Center

|In a recent Monte Carlo simulation study, Liu and Zumbo showed that outliers can severely inflate the estimates of Cronbach's coefficient alpha for continuous item response data--visual analogue response format. Little, however, is known about the effect of outliers for ordinal item response data--also commonly referred to as Likert, Likert-type,…

Liu, Yan; Wu, Amery D.; Zumbo, Bruno D.

2010-01-01

4

SAS and SPSS macros to calculate standardized Cronbach's alpha using the upper bound of the phi coefficient for dichotomous items.  

PubMed

Cronbach's a is widely used in social science research to estimate the internal consistency of reliability of a measurement scale. However, when items are not strictly parallel, the Cronbach's a coefficient provides a lower-bound estimate of true reliability, and this estimate may be further biased downward when items are dichotomous. The estimation of standardized Cronbach's a for a scale with dichotomous items can be improved by using the upper bound of coefficient phi. SAS and SPSS macros have been developed in this article to obtain standardized Cronbach's a via this method. The simulation analysis showed that Cronbach's a from upper-bound phi might be appropriate for estimating the real reliability when standardized Cronbach's a is problematic. PMID:17552473

Sun, Wei; Chou, Chih-Ping; Stacy, Alan W; Ma, Huiyan; Unger, Jennifer; Gallaher, Peggy

2007-02-01

5

Testing hypotheses involving Cronbach's alpha using marginal models.  

PubMed

We discuss the statistical testing of three relevant hypotheses involving Cronbach's alpha: one where alpha equals a particular criterion; a second testing the equality of two alpha coefficients for independent samples; and a third testing the equality of two alpha coefficients for dependent samples. For each of these hypotheses, various statistical tests have been proposed. Over the years, these tests have depended on progressively fewer assumptions. We propose a new approach to testing the three hypotheses that relies on even fewer assumptions, is especially suited for discrete item scores, and can be applied easily to tests containing large numbers of items. The new approach uses marginal modelling. We compared the Type I error rate and the power of the marginal modelling approach to several of the available tests in a simulation study using realistic conditions. We found that the marginal modelling approach had the most accurate Type I error rates, whereas the power was similar across the statistical tests. PMID:23663052

Kuijpers, Renske E; van der Ark, L Andries; Croon, Marcel A

2013-05-13

6

Cronbach's [Alpha], Revelle's [Beta], and McDonald's [Omega][sub H]: Their Relations with Each Other and Two Alternative Conceptualizations of Reliability  

ERIC Educational Resources Information Center

|We make theoretical comparisons among five coefficients--Cronbach's [alpha], Revelle's [beta], McDonald's [omega][sub h], and two alternative conceptualizations of reliability. Though many end users and psychometricians alike may not distinguish among these five coefficients, we demonstrate formally their nonequivalence. Specifically, whereas…

Zinbarg, Richard E.; Revelle, William; Yovel, Iftah; Li, Wen

2005-01-01

7

Factors Affecting Coefficient Alpha: A Mini Monte Carlo Study.  

ERIC Educational Resources Information Center

Factors affecting a lower-bound estimate of internal consistency reliability, Cronbach's coefficient alpha, are explored. Theoretically, coefficient alpha is an estimate of the correlation between two tests drawn at random from a pool of items like the items in the test under consideration. As a practical matter, coefficient alpha can be an index…

Reinhardt, Brian M.

8

Testing the Difference between Two Alpha Coefficients with Small Samples of Subjects and Raters  

ERIC Educational Resources Information Center

Researchers sometimes need a statistical test of the hypothesis that two values of Cronbach's alpha reliability coefficient are equal. The situation may involve scores from two different measures administered to independent random samples or from the same measure administered to random samples from two different populations. Feldt derived a test…

Feldt, Leonard S.; Kim, Seonghoon

2006-01-01

9

Meta-Analysis of Coefficient Alpha  

ERIC Educational Resources Information Center

|The meta-analysis of coefficient alpha across many studies is becoming more common in psychology by a methodology labeled reliability generalization. Existing reliability generalization studies have not used the sampling distribution of coefficient alpha for precision weighting and other common meta-analytic procedures. A framework is provided…

Rodriguez, Michael C.; Maeda, Yukiko

2006-01-01

10

Sample Size Requirements for Testing and Estimating Coefficient Alpha.  

ERIC Educational Resources Information Center

|Derived an approximate test and confidence interval for coefficient alpha and used the approximate test and confidence interval to derive closed-form sample size formulas that can be used to determine the sample size needed to test coefficient alpha with desired power or to test coefficient alpha with desired precision. (SLD)|

Bonett, Douglas G.

2002-01-01

11

The Sampling Distribution of the Kristof Reliability Coefficient, the Feldt Coefficient, and Guttman's Lambda-2  

ERIC Educational Resources Information Center

Two new reliability coefficients have been derived for situations in which a test must be divided into parts of unequal length. This report summarizes a study of the statistical bias and the standard errors of these coefficients and compares them to Guttman's lambda coefficients and Cronbach's alpha coefficient. (Author/JKS)

Sedere, M. U.; Feldt, Leonard S.

1977-01-01

12

Coefficient alpha and the reliability of composite measurements  

Microsoft Academic Search

Following a general approach due to Guttman, coefficient is rederived as a lower bound on the reliability of a test. A necessary and sufficient condition under which equality is attained in this inequality and hence that is equal to the reliability of the test is derived and shown to be closely related to the recent redefinition of the concept of

Melvin R. Novick; Charles Lewis

1967-01-01

13

ScoreRel CI: An Excel Program for Computing Confidence Intervals for Commonly Used Score Reliability Coefficients  

Microsoft Academic Search

An Excel program developed to assist researchers in the determination and presentation of confidence intervals around commonly used score reliability coefficients is described. The software includes programs to determine confidence intervals for Cronbach’s alpha, Pearson r-based coefficients such as those used in test-retest and alternate forms situations, split-half, and Cohen’s 2 × 2 unweighted Kappa. The general basis for the

J. Jackson Barnette

2005-01-01

14

SIMREL: Software for Coefficient Alpha and Its Confidence Intervals with Monte Carlo Studies  

ERIC Educational Resources Information Center

|This article describes SIMREL, a software program designed for the simulation of alpha coefficients and the estimation of its confidence intervals. SIMREL runs on two alternatives. In the first one, if SIMREL is run for a single data file, it performs descriptive statistics, principal components analysis, and variance analysis of the item scores…

Yurdugul, Halil

2009-01-01

15

Measurement of diffusion coefficient of tritium in alpha-phase of zirconium based on glow discharge implantation method  

SciTech Connect

A tritium implantation method based on a glow discharge of tritium gas was applied to the measurement of diffusion coefficient of tritium in alpha-phase of zirconium. The diffusion experiment was carried out in a temperature region from 673 K to 873K, and the diffusion coefficient of tritium was determined as follows, D / (cm{sup 2}/s) = 3.14x10{sup -3} exp (-42.7 RT / (kJ / mol)). The present data were in good agreement with our previous data, which were determined with an usual implantation method based on a nuclear reaction{sup 6}Li(n,{alpha})T. 12 refs., 2 figs., 1 tab.

Hashizume, Ken-ichi; Hatano, Yuji; Sakamoto, Kan; Sugisaki, Masayasu [Kyushu Univ., Fukuoka (Japan)

1995-10-01

16

Methodological problems in the retrospective computation of responsiveness to change: The lesson of Cronbach  

Microsoft Academic Search

Objective: To examine the relation between responsiveness coefficients derived directly from a calculation of average change resulting from a treatment intervention (Responsiveness-Treatment or RT) and those derived from retrospective analysis of changed and unchanged groups (Responsiveness Retrospective or RR) based on a global measure of change. Method: Two approaches were used. First, we used simulation methods to examine the analytical

Geoffrey R. Norman; Paul Stratford; Glenn Regehr

1997-01-01

17

Average multipolarities of quasi-continuum transitions following the (alpha, 4n) reaction from measured internal conversion coefficients  

Microsoft Academic Search

The quasi-continuum of electromagnetic transitions following the 160Gd(alpha,4n)160Dy reaction exhibits predominant E1 character. This is condluded from conversion electrons observed with a mini-orange spectrometer and corresponding gamma-rays, both being selected by coincidences with discrete ground-state band transitions in 160Dy. Permanent address: I.B.J., 05-400 Swierk, Poland.

S. J. Feenstra; W. J. Ockels; J. van Klinken; M. J. A. de Voigt; Z. Sujkowski

1977-01-01

18

Ionic Radical Theory of Crystalline Electro-Optical and Nonlinear Optical Effects. II. Calculation of Second Harmonic Generation Coefficient of alpha -LiIO sub 3 Crystal Using (IO Sub 3 ) exp -1 Radical Molecular Orbitals.  

National Technical Information Service (NTIS)

An (IO sub 3 ) exp -1 ionic radical model is proposed for the SHG effect of iodate crystals. The SHG coefficient for alpha LiIO sub 3 is calculated using (IO sub 3 ) exp -1 radical molecular orbitals and the calculated value agrees well with experimental ...

C. Chen

1977-01-01

19

Investigation of chemical bond characteristics, thermal expansion coefficients and bulk moduli of alpha-R2MoO6 and R2Mo2O7 (R = rare earths) by using a dielectric chemical bond method.  

PubMed

Theoretical researches are performed on the alpha-R2MoO6 (R = Y, Gd, Tb Dy, Ho, Er, Tm and Yb) and pyrochlore-type R2Mo2O7 (R = Y, Nd, Sm, Gd, Tb and Dy) rare earth molybdates by using chemical bond theory of dielectric description. The chemical bonding characteristics and their relationship with thermal expansion property and compressibility are explored. The calculated values of linear thermal expansion coefficient (LTEC) and bulk modulus agree well with the available experimental values. The calculations reveal that the LTECs and the bulk moduli do have linear relationship with the ionic radii of the lanthanides: the LTEC decreases from 6.80 to 6.62 10(-6)/K and the bulk modulus increases from 141 to 154 GPa when R goes in the order Gd, Tb Dy, Ho, Er, Tm, and Yb in the alpha-R2MoO6 series; while in the R2Mo2O7 series, the LTEC ranges from 6.80 to 6.61 10(-6)/K and the bulk modulus ranges from 147 to 163 GPa when R varies in the order Nd, Sm, Gd, Tb and Dy. PMID:19115283

Li, Huaiyong; Zhang, Siyuan; Zhou, Shihong; Cao, Xueqiang

2009-09-01

20

Leptonic widths of heavy quarkonia: S-wave QCD/NRQCD matching coefficients for the electromagnetic vector annihilation current at O({alpha}{sub s}v{sup 2})  

SciTech Connect

We construct the S-wave part of the electromagnetic vector annihilation current to O({alpha}{sub s}v{sup 2}) on the lattice for heavy quarks whose dynamics are described by the NRQCD action, and v is the nonrelativistic quark velocity inside the meson. The lattice vector current for QQ annihilation is expressed as a linear combination of lattice operators with quantum numbers L=0, J{sup P}=1{sup -}, and the coefficients are determined by matching this lattice current to the corresponding continuum current in QCD to O(v{sup 2}) at one-loop. The annihilation channel gives a complex amplitude and a proper choice for the contours of integration is needed; a simple Wick rotation is not possible. In this way, and with a careful choice of subtraction functions in the numerical integration, the Coulomb-exchange and infrared singularities appearing in the amplitudes are successfully treated. The matching coefficients are given as a function of the heavy quark mass Ma in lattice units. An automated vertex generation program written in Python is employed, allowing us to use a realistic NRQCD action and an improved gluon lattice action. A change in the definition of either action is easily accommodated in this procedure. The final result, when combined with lattice simulation results, describes the electromagnetic decays of heavy quarkonia, notably the {upsilon} meson.

Hart, A. [SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Hippel, G. M. von [Department of Physics, University of Regina, Regina, Saskatchewan S4S 0A2 (Canada); Horgan, R. R. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences, Cambridge CB3 0WA (United Kingdom)

2007-01-01

21

Angular Distribution of Alphas from Li6(d,alpha)alpha and Li7(p,alpha)alpha  

Microsoft Academic Search

The intensity of the reaction Li6(d,alpha)alpha is observed to vary with angle as 1+A(E)2theta+B(E)4theta, as expected from the Bose statistics of the product alphas, with A(E) rising gradually beginning just below 1 Mev to a broad maximum a little below unity at a bombarding energy E in the neighborhood of 2 Mev. The coefficient B(E) remains zero up to almost

N. P. Heydenburg; C. M. Hudson; D. R. Inglis; W. D. Whitehead

1948-01-01

22

Transport coefficients of gluonic fluid  

SciTech Connect

The shear ({eta}) and bulk ({zeta}) viscous coefficients have been evaluated for a gluonic fluid. The elastic, gg{yields}gg and the inelastic, number nonconserving, gg{yields}ggg processes have been considered as the dominant perturbative processes in evaluating the viscous coefficients to entropy density (s) ratios. Recently the processes: gg{yields}ggg has been revisited and a correction to the widely used Gunion-Bertsch (GB) formula has been obtained. The {eta} and {zeta} have been evaluated for gluonic fluid with the formula recently derived. At large {alpha}{sub s} the value of {eta}/s approaches its lower bound, {approx}1/4{pi}.

Das, Santosh K.; Alam, Jan-e [Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700064 (India)

2011-06-01

23

Townsend First Coefficient in Argon, Xenon and Their Mixture.  

National Technical Information Service (NTIS)

The ionization coefficient of alpha /P as a function of E/P is determined for argon, xenon and the Ar+0.5% Xe mixture at pressure up to 100 atm. ( alpha - Townsend coefficient, P - gas pressure, E - electric field strength). The findings differ essentiall...

V. K. Dodoknov V. A. Zhukov

1980-01-01

24

Geostrophic drag coefficients over sea ice  

Microsoft Academic Search

The geostrophic drag coefficient, Cg?u*\\/G, and turning angle, alpha were measured October through November 1988 from a 120km array of 6 drifting buoys and a drifting ship in the northern Barents Sea\\/Arctic Ocean during CEAREX; u* is the friction velocity, G is the geostrophic wind, and alpha is the angle between surface stress and . The median Cg was 0.029

James E. Overland; Kenneth L. Davidson

1992-01-01

25

Alpha Thalassemia  

MedlinePLUS

Alpha Thalassemia ? Physicians often mistake alpha thalassemia trait for iron deficiency anemia and incorrectly prescribe iron supplements that have no effect on the anemia. Normal alpha globin genes found on ...

26

INTERNAL CONVERSION COEFFICIENTS - HOW GOOD ARE THEY NOW?  

SciTech Connect

Internal conversion coefficients involving atomic electrons (ICC) and electron-positron pairs (IPC) are often required to determine transition multipolarities and total transition rates. A new internal conversion coefficient data base, BrIcc has been developed which integrates a number of tabulations on ICC and IPC, as well as {Omega}(E0) electronic factors. To decide which theoretical internal conversion coefficient table to use, the accurately determined experimental {alpha}{sub K}, {alpha}{sub L}, {alpha}{sub Total} and {alpha}{sub K}/{alpha}{sub L} values were compared with the new Dirac-Fock calculations using extreme assumptions on the effect of the atomic vacancy. While the overall difference between experiment and theory is less than 1%, our analysis shows preference towards the so called ''Frozen Orbital'' approximation, which takes into account the effect of the atomic vacancy.

KIBEDI,T.; BURROWS, T.W.; TRZHASKOVSKAYA, M.B.; NESTOR, JR., C.W.; DAVIDSON, P.M.

2007-04-22

27

Chromatic aberration coefficients  

NASA Astrophysics Data System (ADS)

Our work deals with the influence of the wavelength of light on values of wave aberration coefficients. It is proposed a technique for calculation of the dependence of aberration coefficients on the wavelength, their interpretation and the connection to chromatic aberrations. It is also shown the calculation of the Strehl definition using chromatic aberration coefficients and the tolerance limits are given. The proposed method for calculation of chromatic aberration coefficients is shown for the case of the imaging of axial point by the rotationally symmetrical optical system. Relations that enable calculation of chromatic aberration coefficients up to fifth order are carried out. These relations are accurate enough for most optical systems in practice.

Miks, Antonin; Novak, Jiri; Novak, Pavel

2007-05-01

28

Coefficients of Effective Length.  

ERIC Educational Resources Information Center

Under certain conditions, a validity Coefficient of Effective Length (CEL) can produce highly misleading results. A modified coefficent is suggested for use when empirical studies indicate that underlying assumptions have been violated. (Author/BW)

Edwards, Roger H.

1981-01-01

29

Bounding the Bogoliubov coefficients  

SciTech Connect

While over the last century or more considerable effort has been put into the problem of finding approximate solutions for wave equations in general, and quantum mechanical problems in particular, it appears that as yet relatively little work seems to have been put into the complementary problem of establishing rigourous bounds on the exact solutions. We have in mind either bounds on parametric amplification and the related quantum phenomenon of particle production (as encoded in the Bogoliubov coefficients), or bounds on transmission and reflection coefficients. Modifying and streamlining an approach developed by one of the present authors [M. Visser, Phys. Rev. A 59 (1999) 427-438, (arXiv:quant-ph/9901030)], we investigate this question by developing a formal but exact solution for the appropriate second-order linear ODE in terms of a time-ordered exponential of 2x2 matrices, then relating the Bogoliubov coefficients to certain invariants of this matrix. By bounding the matrix in an appropriate manner, we can thereby bound the Bogoliubov coefficients.

Boonserm, Petarpa [School of Mathematics, Statistics, and Computer Science, Victoria University of Wellington, P.O. Box 600, Wellington (New Zealand); Visser, Matt [School of Mathematics, Statistics, and Computer Science, Victoria University of Wellington, P.O. Box 600, Wellington (New Zealand)], E-mail: matt.visser@mcs.vuw.ac.nz

2008-11-15

30

Sample Size Requirements for Comparing Two Alpha Coefficients.  

ERIC Educational Resources Information Center

|Derived general formulas to determine the sample size requirements for hypothesis testing with desired power and interval estimation with desired precision. Illustrated the approach with the example of a screening test for adolescent attention deficit disorder. (SLD)|

Bonnett, Douglas G.

2003-01-01

31

Coefficients Alpha, Beta, Omega, and the glb: Comments on Sijtsma  

ERIC Educational Resources Information Center

|There are three fundamental problems in Sijtsma ("Psychometrika," 2008): (1) contrary to the name, the glb is not the greatest lower bound of reliability but rather is systematically less than omega[subscript t] (McDonald, "Test theory: A unified treatment," Erlbaum, Hillsdale, 1999), (2) we agree with Sijtsma that when considering how well a…

Revelle, William; Zinbarg, Richard E.

2009-01-01

32

Metastable ion study of fluorinated organic compounds. Part 3. [alpha], [alpha], [alpha]-trifluoroanisole and [alpha], [alpha], [alpha]-trifluorocresols  

Microsoft Academic Search

The spontaneous unimolecular dissociation reactions of the molecular ions of the C7H5F3O positional isomers [alpha], [alpha], [alpha]-trifluoroanisole (1), o-[alpha], [alpha], [alpha],-trifluorocresol (2) and m-[alpha], [alpha], [alpha]-trilfluorocresol (3), have been investigated by mass-analyzed ion kinetic energy (MIKE) spectrometry and deuterium-labellin. The results are compared with those of the non-fluorinated analogues anisole (4), o-cresol (5) and m-cresol (6). Ions 1.+ and 4.+

Tamae Yanagisawa; Susumu Tajima; Masaki Iizuka; Seiji Tobita; Motohiro Mitani; Takeo Matsumoto

1993-01-01

33

Buchdahl's glass dispersion coefficients calculated in the near infrared.  

PubMed

Buchdahl's chromatic coordinate provides a rapidly converging polynomial form for describing the dispersion of glass. A method of generating Buchdahl's chromatic coordinate coefficients with a Code V sequence file is presented. The quadratic model coefficients for eighty-two glasses at a base wavelength of 0.830 microm are listed. When evaluating Buchdahl coefficients across different wavelength ranges (i.e., infrared or ultraviolet), the chromatic coordinate constant alpha can be changed to improve convergence of the refractive-index model. PMID:20548543

Chipman, R A; Reardon, P J

1989-02-15

34

The Transport Coefficients  

NASA Astrophysics Data System (ADS)

In this section we wish to give a detailed account of all the transport coefficients related to the vectorial fluxes discussed in the previous chapters. These are the mass flux Ja (=-Jb ), the corresponding charge flux or electrical current Jc , closely related to Ja , and J^'q the heat flux. In every case the magnetic field is chosen as the direction of the z-axis, B=Bhat{k} so that for any vector, its different components respect to B will follow from the decomposition illustrated in Fig. (4.1).

García-Colín, Leopoldo S.; Dagdug, Leonardo

35

A Novel Approach for Optimal Location and Sizing of Capacitors on Radial Distribution Systems Using Loss Sensitivity Factors and ?- Coefficients  

Microsoft Academic Search

This paper presents a novel approach that determines the optimal location and size of capacitors on radial distribution systems to improve voltage profile and reduce the active power loss. Capacitor placement & sizing are done by loss sensitivity factors and alpha-coefficients respectively. The concept of loss sensitivity factors and alpha-coefficients can be considered as the new contribution in the area

K. Prakash; M. Sydulu

2006-01-01

36

Experimental Determination of the Kinetic Coefficients for Water Using Nucleation and Evaporation Rates: Sensitivity to Vapor Pressure  

Microsoft Academic Search

If we are to understand the growth\\/evaporation rates, nucleation rates, and activation rates of atmospheric aerosol particles, we must have an understanding of the kinetics of mass and energy exchange between the surface of an aerosol particle and the surrounding gas. Laboratory experiments to determine the thermal accommodation alpha t coefficient and condensation coefficient alpha c of liquid water have

R. A. Shaw; D. Lamb

2001-01-01

37

Drag Coefficient of Hexadecane Particles  

NASA Astrophysics Data System (ADS)

This paper deals with the drag coefficient of solidified hexadecane particles and their free rising velocity in liquid. The drag coefficient was experimentally investigated in Reynolds number range of about 40-300. The present experimental results are summarized in the following; (1) the drag coefficient of solidified hexadecane particles formed in liquid coolant by direct contact cooling is higher than that of a smooth surface sphere, this high drag coefficient seems to be attributed to the non-smooth surface of the solidified hexadecane particles, (2) experimental correlation for the drag coefficient of the solidified hexadecane particles was proposed, (3 ) the measured rising velocity of the solidified hexadecane particle agrees well with the calculated one, (4) the drag coefficients of hexadecane particles that were made by pouring hexadecane liquid into a solid hollow sphere agreed well with the drag coefficient of smooth surface sphere.

Nakao, Yoshinobu; Hishida, Makoto; Kajimoto, Sadaaki; Tanaka, Gaku

38

Quadrature formulas for Fourier coefficients  

NASA Astrophysics Data System (ADS)

We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives.

Bojanov, Borislav; Petrova, Guergana

2009-09-01

39

Coefficient inverse problem for a fractional diffusion equation  

NASA Astrophysics Data System (ADS)

In this paper, we consider an initial/boundary value problem for a fractional diffusion equation in a bounded domain ?: \\partial _t^{\\alpha }u = \\Delta u + p(x)u where \\partial _t^{\\alpha } is the Caputo derivative and 0 < ? < 2, ? ? 1. We discuss an inverse problem of determining spatial coefficient p(x), x ? ? and/or order ? of the fractional derivative by data u|? × (0, T), where ??? is a sub-domain. Our main result is the uniqueness under conditions where the initial value is positive and ? is a neighbourhood of ??. The proof is done by transforming the solution u to the solution of the wave equation.

Miller, Luc; Yamamoto, Masahiro

2013-07-01

40

Indirect band gap in alpha-ZrO2  

SciTech Connect

Measurements of the absorption coefficient on the fundamental optical absorption edge of alpha ZrO2 show that an indirect interband transition at 4.70 eV precedes two previously reported direct transitions. This result is in agreement with recent theoretical calculations of the alpha ZrO2 band structure. (JS)

Kwok, C.K.; Aita, C.R.

1990-08-01

41

Power Coefficient Anomaly in JOYO.  

National Technical Information Service (NTIS)

Power Coefficient Anomaly appeared in JOYO, which occurred in 75MW Power Ascension Test, Summer 1979. The substance of this anomaly was the non-reproducible power coefficient during the initial power-up from 50MWt to 75MWt and the permanent reactivity los...

M. Ishikawa Y. Yamashita Y. Nara H. Yamamoto

1981-01-01

42

RADIONUCLIDE RISK COEFFICIENT UNCERTAINTY REPORT  

EPA Science Inventory

EPA has published excess cancer risk coefficients for the US population in Federal Guidance Report 13 (FGR 13). FGR 13 gives separate risk coefficients for food ingestion, water ingestion, inhalation, and external exposure for each of over 800 radionuclides. Some information on...

43

Calculate thermal-expansion coefficients  

Microsoft Academic Search

To properly design and use process equipment, an engineer needs a sound knowledge of physical and thermodynamic property data. A lack of such knowledge can lead to design or operating mistakes that can be dangerous, costly or even fatal. One useful type of property data is the thermal-expansion coefficient. This article presents equations and tables to find the thermal-expansion coefficients

Yaws

1995-01-01

44

Anisotropic Diffusion of sup 51 Cr in Zr- alpha Monocrystals.  

National Technical Information Service (NTIS)

The volume diffusion coefficients of the fast-diffusing solute sup 51 Cr were obtained in oriented alpha -Zr single-crystals, in the directions parallel and perpendicular to the c axis. The dependence of those diffusion coefficients with temperature was a...

N. Varela S. Balart R. Tendler

1983-01-01

45

Cytoplasmic hydrogen ion diffusion coefficient.  

PubMed Central

The apparent cytoplasmic proton diffusion coefficient was measured using pH electrodes and samples of cytoplasm extracted from the giant neuron of a marine invertebrate. By suddenly changing the pH at one surface of the sample and recording the relaxation of pH within the sample, an apparent diffusion coefficient of 1.4 +/- 0.5 x 10(-6) cm2/s (N = 7) was measured in the acidic or neutral range of pH (6.0-7.2). This value is approximately 5x lower than the diffusion coefficient of the mobile pH buffers (approximately 8 x 10(-6) cm2/s) and approximately 68x lower than the diffusion coefficient of the hydronium ion (93 x 10(-6) cm2/s). A mobile pH buffer (approximately 15% of the buffering power) and an immobile buffer (approximately 85% of the buffering power) could quantitatively account for the results at acidic or neutral pH. At alkaline pH (8.2-8.6), the apparent proton diffusion coefficient increased to 4.1 +/- 0.8 x 10(-6) cm2/s (N = 7). This larger diffusion coefficient at alkaline pH could be explained quantitatively by the enhanced buffering power of the mobile amino acids. Under the conditions of these experiments, it is unlikely that hydroxide movement influences the apparent hydrogen ion diffusion coefficient.

al-Baldawi, N F; Abercrombie, R F

1992-01-01

46

Negative coefficient of normal restitution  

NASA Astrophysics Data System (ADS)

This paper shows that negative coefficients of normal restitution occur inevitably when the interaction force between colliding particles is finite. We derive an explicit criterion showing that for any set of material properties there is always a collision geometry leading to negative restitution coefficients. While from a phenomenological point of view, negative coefficients of normal restitution appear rather artificial, this phenomenon is generic and implies an important overlooked limitation of the widely used hard sphere model. The criterion is explicitly applied to two paradigmatic situations: for the linear dashpot model and for viscoelastic particles. In addition, we show that for frictional particles the phenomenon is less pronounced than for smooth spheres.

Müller, Patric; Krengel, Dominik; Pöschel, Thorsten

2012-04-01

47

Resonance scattering and alpha-transfer reactions for nuclear astrophysics  

SciTech Connect

Resonances in atomic nuclei play a vital role in determining rates of astrophysically important nuclear reactions. Efficient experimental technique, Thick Target Inverse Kinematics method, which allows to study properties of resonances in exotic nuclei with radioactive beams using resonance elastic scattering is discussed. Various extensions of this technique for measurements of inelastic excitation functions and application of one of these methods for {sup 7}Be(p,p'){sup 7}Be*(0.43 MeV) reaction is considered.The astrophysical rates of some (alpha, gamma), (alpha, n), (alpha, p) reactions are often determined by the near alpha-threshold resonances. Application of sub-Coulomb alpha-transfer reactions ({sup 7}Li,t) and ({sup 6}Li,d) allow to determine alpha-particle Asymptotic Normalization Coefficients of these resonances with minimal dependance on model parameters. The {sup 14}C(alpha,gamma) reaction is considered as an example for application of this approach.

Rogachev, G. V.; Johnson, E. D.; Mitchell, J.; Kemper, K. W.; Wiedenhoever, I. [Department of Physics, Florida State University, 32312 FL (United States); Goldberg, V. Z. [Cyclotron Institute, Texas A and M University, TX (United States)

2010-03-01

48

The Condensation Coefficient of Aln.  

National Technical Information Service (NTIS)

The condensation coefficient of AlN was measured by following the rate of exchange is isotopic N2 gas (N15) with AlN14(s) and that of N2 gas (N14) with AlN15(s) using a time-of-flight mass spectrometer. The isotopic N2 gas (N15) was generated by decomposi...

M. Hoch D. Ramakrishnan

1965-01-01

49

TOPAZ II Temperature Coefficient Analyses  

NASA Astrophysics Data System (ADS)

A two-dimensional model of the Topaz II reactor core suitable for neutronic analyses of temperature coefficients of reactivity is presented. The model is based on a 30° r-theta segment of the core. Results of TWODANT calculations are used to estimate temperature coefficients associated with fuel, electrodes, moderator, reflector, and tube plates over the range of temperatures anticipated during startup and operation. Results are presented to assess the reactivity effects associated with Doppler broadening, spectral effects and thermal expansion. Comparisons are made between the TWODANT results and empirical Russian curves used for simulating Topaz II system transients. TWODANT results indicate that the prompt temperature coefficients associated with temperature changes in fuel and emitters are negative. This is primarily because of Doppler broadening of the absorption resonances of uranium and molybdenum. The delayed effect of tube plate heating is also negative because fuel is moved radially outward in the core where it is less important. Temperature coefficients associated with delayed heating of the zirconium hydride moderator and the Beryllium reflector are positive, as the change in the neutron spectrum with moderator or reflector temperature decreases the rate of absorption in these components. The TWODANT results agree with the results obtained from the empirical Russian correlations.

Loaiza, David; Haskin, F. Eric; Marshall, Albert C.

1994-07-01

50

Geometrical content of Leslie coefficients.  

PubMed

In this work, we will study how the effective geometry acquired by nematic molecules under thermal vibration contribute to the determination of the Leslie coefficients. To do this, we will divide this work in two sections. In the first section, we present the geometrical fundamentals of the so-called Hess-Baalss (HB) approach [D. Baalss and S. Hess, Phys. Rev. Lett. 57, 86 (1986)] where we show that its basic assumptions can be understood as a geometrical interpretation of de Gennes' passage from the microscopic to the macroscopic order parameter. In the second section, we use an extended version of the HB approach [M. Simões, K. Yamaguti, and A. J. Palangana, Phys. Rev. E 80, 061701 (2009)] to obtain the geometrical contribution to each Leslie coefficient. Our results will be compared with experimental data, and we will show that the Miesowicz's coefficients are connected as long as the ratio ?(3)/?(4) between these Leslie coefficients can be considered small. PMID:21728551

Simões, M; da Silva, J L Correia

2011-05-10

51

Geometrical content of Leslie coefficients  

NASA Astrophysics Data System (ADS)

In this work, we will study how the effective geometry acquired by nematic molecules under thermal vibration contribute to the determination of the Leslie coefficients. To do this, we will divide this work in two sections. In the first section, we present the geometrical fundamentals of the so-called Hess-Baalss (HB) approach [D. Baalss and S. Hess, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.57.86 57, 86 (1986)] where we show that its basic assumptions can be understood as a geometrical interpretation of de Gennes’ passage from the microscopic to the macroscopic order parameter. In the second section, we use an extended version of the HB approach [M. Simões, K. Yamaguti, and A. J. Palangana, Phys. Rev. EPHRVAO1539-375510.1103/PhysRevE.80.061701 80, 061701 (2009)] to obtain the geometrical contribution to each Leslie coefficient. Our results will be compared with experimental data, and we will show that the Miesowicz’s coefficients are connected as long as the ratio ?3/?4 between these Leslie coefficients can be considered small.

Simões, M.; da Silva, J. L. Correia

2011-05-01

52

Identities for generalized hypergeometric coefficients  

SciTech Connect

Generalizations of hypergeometric functions to arbitrarily many symmetric variables are discussed, along with their associated hypergeometric coefficients, and the setting within which these generalizations arose. Identities generalizing the Euler identity for {sub 2}F{sub 1}, the Saalschuetz identity, and two generalizations of the {sub 4}F{sub 3} Bailey identity, among others, are given. 16 refs.

Biedenharn, L.C.; Louck, J.D.

1991-01-01

53

Factoring Polynomials with Rational Coefficients.  

National Technical Information Service (NTIS)

A polynomial-time algorithm for the factorization of polynomials in one variable with rational coefficients is described. First a suitable small prime number p is found, a p-adic irreducible factor h of the polynomial f. This is done with Berlekamp's algo...

A. K. Lenstra H. W. Lenstra L. Lovasz

1982-01-01

54

Effective Viscosity Coefficient of Nanosuspensions  

NASA Astrophysics Data System (ADS)

Systematic calculations of the effective viscosity coefficient of nanosuspensions have been performed using the molecular dynamics method. It is established that the viscosity of a nanosuspension depends not only on the volume concentration of the nanoparticles but also on their mass and diameter. Differences from Einstein's relation are found even for nanosuspensions with a low particle concentration.

Rudyak, V. Ya.; Belkin, A. A.; Egorov, V. V.

2008-12-01

55

Composition of Partition Coefficients of  

Microsoft Academic Search

Partition coefficients (P) of tri-, tetra-, penta-, and hexa-chlorocyclohexene isomers were measured in an octanol\\/water system. These log P values and values previously determined for polychlorocy- clohexane isomers and some polychlorinated acyclic alkenes were analyzed by the summation of the hydrophobic fragment constants of their structural units and features. The introduction of new fragment constants, including interactive and conformational factors,

Norio KURIHARA

56

Prediction of stream volatilization coefficients  

USGS Publications Warehouse

Equations are developed for predicting the liquid-film and gas-film reference-substance parameters for quantifying volatilization of organic solutes from streams. Molecular weight and molecular-diffusion coefficients of the solute are used as correlating parameters. Equations for predicting molecular-diffusion coefficients of organic solutes in water and air are developed, with molecular weight and molal volume as parameters. Mean absolute errors of prediction for diffusion coefficients in water are 9.97% for the molecular-weight equation, 6.45% for the molal-volume equation. The mean absolute error for the diffusion coefficient in air is 5.79% for the molal-volume equation. Molecular weight is not a satisfactory correlating parameter for diffusion in air because two equations are necessary to describe the values in the data set. The best predictive equation for the liquid-film reference-substance parameter has a mean absolute error of 5.74%, with molal volume as the correlating parameter. The best equation for the gas-film parameter has a mean absolute error of 7.80%, with molecular weight as the correlating parameter.

Rathbun, Ronald, E.

1990-01-01

57

Alpha Thalassemia (For Parents)  

MedlinePLUS

Thalassemias Thalassemias are a group of blood disorders that affect the way the body makes hemoglobin, a ... results in that type of thalassemia. About Alpha Thalassemia Alpha thalassemia occurs when the gene that controls ...

58

Alpha-1 Antitrypsin Deficiency  

MedlinePLUS

Alpha-1 antitrypsin deficiency is an inherited disorder that can cause lung disease in adults and liver disease in adults and children. Alpha-1 antitrypsin (AAT) is a protein that protects the lungs. ...

59

The Alpha Centauri System.  

ERIC Educational Resources Information Center

Describes the Alpha Centauri star system, which is the closest star system to the sun. Discusses the difficulties associated with measurements involving Alpha Centauri, along with some of the recent advances in stellar seismology. Raises questions about the possibilities of planets around Alpha Centauri. (TW)

Soderblom, David R.

1987-01-01

60

The Alpha Centauri System.  

ERIC Educational Resources Information Center

|Describes the Alpha Centauri star system, which is the closest star system to the sun. Discusses the difficulties associated with measurements involving Alpha Centauri, along with some of the recent advances in stellar seismology. Raises questions about the possibilities of planets around Alpha Centauri. (TW)|

Soderblom, David R.

1987-01-01

61

Portable vapor diffusion coefficient meter  

DOEpatents

An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.

Ho, Clifford K. (Albuquerque, NM)

2007-06-12

62

Elastic coefficients of animal bone.  

PubMed

The elastic stiffness coefficients of dried bovine phalanx and femur and of fresh bovine phalanx were measured by an ultrasonic technique. An analysis of the crystallographic structure of the principal components of bone and its piezoelectric and pyroelectric behavior showed that bone is a texture that has the same elastic coeffcient matrix as a hexagonal single crystal. The five elastic stiffness coefficients of fresh phalanx are: C(1l), 1.97; C(12), 1.21; C(13), 1.26; C(33), 3.20; and C(44), 0.54 (all in units of 10(11) dynes per square centimeter). Value of axial and transverse Young's and shear moduli, compressibility, and the three Poisson's ratios were calculated. PMID:5787984

Lang, S B

1969-07-18

63

High temperature Seebeck coefficient metrology  

SciTech Connect

We present an overview of the challenges and practices of thermoelectric metrology on bulk materials at high temperature (300 to 1300 K). The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at high temperature. This has led to the implementation of nonideal practices that have further complicated the confirmation of reported high ZT materials. To ensure meaningful interlaboratory comparison of data, thermoelectric measurements must be reliable, accurate, and consistent. This article will summarize and compare the relevant measurement techniques and apparatus designs required to effectively manage uncertainty, while also providing a reference resource of previous advances in high temperature thermoelectric metrology.

Martin, J. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Tritt, T. [Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634 (United States); Uher, C. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2010-12-15

64

Factoring polynomials with rational coefficients  

Microsoft Academic Search

In this paper we present a polynomial-time algorithm to solve the following problem: given a non-zero polynomial fe Q(X) in one variable with rational coefficients, find the decomposition of f into irreducible factors in Q(X). It is well known that this is equivalent to factoring primitive polynomials feZ(X) into irreducible factors in Z(X). Here we call f~ Z(X) primitive if

A. K. Lenstra; H. W. Lenstra; L. Lovfiasz

1982-01-01

65

Ionization coefficients in gas mixtures  

NASA Astrophysics Data System (ADS)

We have tested the application of the common E/N (E—electric field, N—gas number density) or Wieland approximation [Van Brunt, R.J., 1987. Common parametrizations of electron transport, collision cross section, and dielectric strength data for binary gas mixtures. J. Appl. Phys. 61 (5), 1773 1787.] and the common mean energy (CME) combination of the data for pure gases to obtain ionization coefficients for mixtures. Test calculations were made for Ar CH4, Ar N2, He Xe and CH4 N2 mixtures. Standard combination procedure gives poor results in general, due to the fact that the electron energy distribution is considerably different in mixtures and in individual gases at the same values of E/N. The CME method may be used for mixtures of gases with ionization coefficients that do not differ by more than two orders of magnitude which is better than any other technique that was proposed [Mari?, D., Radmilovi?-Ra?enovi?, M., Petrovi?, Z.Lj., 2005. On parametrization and mixture laws for electron ionization coefficients. Eur. Phys. J. D 35, 313 321.].

Mari?, D.; Šaši?, O.; Jovanovi?, J.; Radmilovi?-Ra?enovi?, M.; Petrovi?, Z. Lj.

2007-03-01

66

The Multiple-Partial Correlation Coefficient  

Microsoft Academic Search

A partial correlation coefficient which is also a multiple correlation coefficient is discussed. Its relationship with other well-known coefficients is explained. Computational methods for computing the estimating equation and the correlation coefficient are suggested.* The writer wishes to thank Professors Harold Hotelling, George E. Nicholson, and John H. Smith for critically reading the manuscript and offering valuable comments. Professor Hotelling

Dudley J. Cowden

1952-01-01

67

Heat transfer coefficients beneath inclined turbulent impinging jets  

NASA Astrophysics Data System (ADS)

An experimental study of the local heat and mass transfer coefficients associated with the impingement of inclined turbulent circular jets onto flat plates is presented. A single free jet exiting into initially stagnant surroundings was considered, and the nozzle inclination, alpha, was varied from 30 to 90 deg to the impingement surface. The heat transfer rate is virtually insensitive to nozzle inclination if the distance along the axis of the jet is used. The 'thin-film' naphthalene sublimation technique was employed for the mass transfer measurements.

Oladiran, M. T.

68

Alpha-2 Adrenergic Receptor Polymorphisms.  

National Technical Information Service (NTIS)

The present invention includes polymorphisms in nucleic acids encoding the alpha-2B, alpha-2A, and alpha-2C adrenergic receptor and expressed alpha-2B, alpha2A and alpha-2C adrenergic receptor molecule. The invention also pertains to methods and molecules...

K. M. Small S. B. Liggett

2005-01-01

69

Diffusion coefficients for stellar plasmas  

NASA Astrophysics Data System (ADS)

The diffusion coefficients of relatively dense plasmas that are typical of white dwarf envelopes are presently computed by means of an approximate method, based on the numerical evaluation of collision integrals for a screened Coulomb potential, which becomes rigorously valid in the limit of a dilute plasma. The plasmas encountered in white dwarf envelopes are noted to be neither weakly nor strongly coupled; a comparison with the results of rigorous Monte Carlo calculations applicable at very high densities indicates, however, that the region of intermediate coupling is probably reasonably bridged. Results are presented in the form of high accuracy analytic fits for the collision integrals.

Paquette, C.; Pelletier, C.; Fontaine, G.; Michaud, G.

1986-05-01

70

Measurements of thermal accommodation coefficients.  

SciTech Connect

A previously-developed experimental facility has been used to determine gas-surface thermal accommodation coefficients from the pressure dependence of the heat flux between parallel plates of similar material but different surface finish. Heat flux between the plates is inferred from measurements of temperature drop between the plate surface and an adjacent temperature-controlled water bath. Thermal accommodation measurements were determined from the pressure dependence of the heat flux for a fixed plate separation. Measurements of argon and nitrogen in contact with standard machined (lathed) or polished 304 stainless steel plates are indistinguishable within experimental uncertainty. Thus, the accommodation coefficient of 304 stainless steel with nitrogen and argon is estimated to be 0.80 {+-} 0.02 and 0.87 {+-} 0.02, respectively, independent of the surface roughness within the range likely to be encountered in engineering practice. Measurements of the accommodation of helium showed a slight variation with 304 stainless steel surface roughness: 0.36 {+-} 0.02 for a standard machine finish and 0.40 {+-} 0.02 for a polished finish. Planned tests with carbon-nanotube-coated plates will be performed when 304 stainless-steel blanks have been successfully coated.

Rader, Daniel John; Castaneda, Jaime N.; Torczynski, John Robert; Grasser, Thomas W.; Trott, Wayne Merle

2005-10-01

71

The generalized liquid drop model alpha-decay formula: Predictability analysis and superheavy element alpha half-lives  

SciTech Connect

The predictive accuracy of the generalized liquid drop model (GLDM) formula for alpha-decay half-lives has been investigated in a detailed manner and a variant of the formula with improved coefficients is proposed. The method employs the experimental alpha half-lives of the well-known alpha standards to obtain the coefficients of the analytical formula using the experimental Q{sub {alpha}} values (the DSR-E formula), as well as the finite range droplet model (FRDM) derived Q{sub {alpha}} values (the FRDM-FRDM formula). The predictive accuracy of these formulae was checked against the experimental alpha half-lives of an independent set of nuclei (TEST) that span approximately the same Z, A region as the standards and possess reliable alpha spectroscopic data, and were found to yield good results for the DSR-E formula but not for the FRDM-FRDM formula. The two formulae were used to obtain the alpha half-lives of superheavy elements (SHE) and heavy nuclides where the relative accuracy was found to be markedly improved for the FRDM-FRDM formula, which corroborates the appropriateness of the FRDM masses and the GLDM prescription for high Z, A nuclides. Further improvement resulted, especially for the FRDM-FRDM formula, after a simple linear optimization over the calculated and experimental half-lives of TEST was used to re-calculate the half-lives of the SHE and heavy nuclides. The advantage of this optimization was that it required no re-calculation of the coefficients of the basic DSR-E or FRDM-FRDM formulae. The half-lives for 324 medium-mass to superheavy alpha decaying nuclides, calculated using these formulae and the comparison with experimental half-lives, are presented.

Dasgupta-Schubert, N. [Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Cd. Universitaria, Morelia, Michoacan C.P. 58060 (Mexico)], E-mail: nita@ifm.umich.mx; Reyes, M.A. [Department of Electrical Engineering, University of Texas Pan American, Edinburg, TX 78539 (United States)

2007-11-15

72

Rossi Alpha Method  

SciTech Connect

The Rossi Alpha Method has proved to be valuable for the determination of prompt neutron lifetimes in fissile assemblies having known reproduction numbers at or near delayed critical. This workshop report emphasizes the pioneering applications of the method by Dr. John D. Orndoff to fast-neutron critical assemblies at Los Alamos. The value of the method appears to disappear for subcritical systems where the Rossi-..alpha.. is no longer an ..alpha..-eigenvalue.

Hansen, G.E.

1985-01-01

73

Turbulent transport coefficients and residual energy in mean-field dynamo theory  

SciTech Connect

The turbulent electromotive force in the mean-field equation needs to be modeled to predict a large-scale magnetic field in magnetohydrodynamic turbulence at high Reynolds number. Using a statistical theory for inhomogeneous turbulence, model expressions for transport coefficients appearing in the turbulent electromotive force are derived including the {alpha} coefficient and the turbulent diffusivity. In particular, as one of the dynamo effects, the pumping effect is investigated and a model expression for the pumping term is obtained. It is shown that the pumping velocity is closely related to the gradient of the turbulent residual energy, or the difference between the turbulent kinetic and magnetic energies. The production terms in the transport equation for the turbulent electromotive force are also examined and the validity of the model expression is assessed by comparing with earlier results concerning the isotropic {alpha} coefficient. The mean magnetic field in a rotating spherical shell is calculated using a turbulence model to demonstrate the pumping effect.

Hamba, Fujihiro [Institute of Industrial Science, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Sato, Hisanori [Japan Patent Office, Kasumigaseki, Chiyoda-ku, Tokyo 100-8915 (Japan)

2008-02-15

74

Antioxidant effects of alpha- and gamma-carboxyethyl-6-hydroxychromans.  

PubMed

Carboxyethyl-6-hydroxychromans (CEHC), the major metabolites of both tocopherols (Toc) and tocotrienols (Toc-3), have been found in human plasma. In the present study, the antioxidant properties of alpha- and gamma-CEHC were measured and compared with alpha- and gamma- tocopherols. Following results were obtained: (1)alpha- and gamma-CEHC have the same reactivities toward radicals and exert the same antioxidant activities against lipid peroxidation in organic solution as the corresponding parent tocopherols respectively; (2) the partition coefficient decreased in the order alpha-Toc (3.36) > gamma-Toc (3.14) > alpha-CEHC (2.26) > pentamethyl-6-chromanol (1.92) > gamma-CEHC (1.83) > 0 > Trolox (-0.97); (3) alpha- and gamma-CEHC scavenge aqueous radicals more efficiently but they inhibit the lipid peroxidation within the membranes less efficiently than the corresponding alpha- and gamma-Toc, respectively; (4) alpha-CEHC inhibits the oxidation synergistically with ascorbate; and (5) alpha- and gamma-CEHC reduce Cu(II) to give Cu(I) and corresponding quinones as major product, but the prooxidant effect of CEHC in the presence of cupric ion was small. These results imply that CEHC may act as an antioxidant in vivo especially for those who take tocopherol supplement. PMID:14530597

Yoshida, Yasukazu; Niki, Etsuo

2002-01-01

75

Nitrogen Dioxide Absorption Coefficients at High Temperatures.  

National Technical Information Service (NTIS)

The absorption coefficient of nitrogen dioxide, NO2, is used in models of the fireball resulting from atmospheric nuclear detonations. This report gives values for the absorption coefficient obtained at wavelengths between 380 and 760 nm and at temperatur...

D. E. Paulsen R. E. Huffman

1976-01-01

76

ACTIVITY COEFFICIENTS OF CARBAMOYLMETHYLPHOSPHORYL EXTRACTANTS IN TOLUENE  

Microsoft Academic Search

The activity coefficients of four extractants belonging to the carbamoylmethylphosphoryl class were measured by vapor-phase osmometry. All of the activity coefficients were within 15% of unity for concentrations up to 0.5 M in toluene. As the basicity of the extractant's phosphoryl-group increases, its activity coefficient decreases. Octylphenyl-N,N-diisobutylcarbamoylmethyl-phosphine oxide [O?D(iB)CMPO] in toluene exhibited a marked decrease in activity coefficient upon equilibration

H. Diamond; E. P. Horwitz; P. R. Danesi

1986-01-01

77

Internal conversion coefficients of high multipole transitions: Experiment and theories  

SciTech Connect

A compilation of the available experimental internal conversion coefficients (ICCs), {alpha}{sub T}, {alpha}{sub K}, {alpha}{sub L}, and ratios K/L and K/LM of high multipole (L > 2) transitions for a number of elements in the range 21 {<=} Z {<=} 94 is presented. Our listing of experimental data includes 194 data sets on 110 E3 transitions, 10 data sets on 6 E4 transitions, 11 data sets on 7 E5 transitions, 38 data sets on 21 M3 transitions, and 132 data sets on 68 M4 transitions. Data with less than 10% experimental uncertainty have been selected for comparison with the theoretical values of Hager and Seltzer [R.S. Hager, E.C. Seltzer, Nucl. Data Tables A 4 (1968) 1], Rosel et al. [F. Roesel, H.M. Fries, K. Alder, H.C. Pauli, At. Data Nucl. Data Tables 21 (1978) 91], and BRICC. The relative percentage deviations (%{delta}) have been calculated for each of the above theories and the averages (%{delta}-bar) are estimated. The Band et al. [I.M. Band, M.B. Trzhaskovskaya, C.W. Nestor Jr., P.O. Tikkanen, S. Raman, At. Data Nucl. Data Tables 81 (2002) 1] tables, using the BRICC interpolation code, are seen to give theoretical ICCs closest to experimental values.

Gerl, J. [Gesellschaft fuer Schwerionenforschung, GSI, Planck Strasse 1, D-64291 Darmstadt (Germany); Vijay Sai, K. [Department of Physics, Sri Sathya Sai University, Prasanthinilayam 515134 (India)], E-mail: vjsai.phy.psn@sssu.edu.in; Sainath, M.; Gowrishankar, R.; Venkataramaniah, K. [Department of Physics, Sri Sathya Sai University, Prasanthinilayam 515134 (India)

2008-09-15

78

widehat {su}( 3 ; )k FUSION COEFFICIENTS  

NASA Astrophysics Data System (ADS)

A closed and explicit formula for all widehat {su}( 3 ; )k fusion coefficients is presented which, in the limit k??, turns into a simple and compact expression for the su(3) tensor product coefficients. The derivation is based on a new diagrammatic method which gives directly both tensor product and fusion coefficients.

Bégin, L.; Mathieu, P.; Walton, M. A.

79

Note on Methodology: The Coefficient of Variation.  

ERIC Educational Resources Information Center

Addresses applications of the coefficient of variation as a measure of educational inequality or as a means of measuring changes of inequality status. Suggests the Gini coefficient has many advantages over the coefficient of variation since it can be used with the Lorenz curve (Lorenz provides detail Gini omits). (BRR)

Sheret, Michael

1984-01-01

80

Temperature coefficients of rare earth permanent magnets  

Microsoft Academic Search

A new approach for calculating the temperature coefficients of magnetic parameters is proposed in order to more accurately describe high temperature characteristics of magnetic materials. Using this new approach, the “true” (or instantaneous) temperature coefficient of any magnetic parameter at a specific temperature can be determined and a plot of temperature coefficient vs. temperature can be obtained. This new type

Sam Liu; G. Edward Kuhl

1999-01-01

81

Standards for Standardized Logistic Regression Coefficients  

ERIC Educational Resources Information Center

|Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…

Menard, Scott

2011-01-01

82

M-Bonomial Coefficients and Their Identities  

ERIC Educational Resources Information Center

|In this note, we introduce M-bonomial coefficients or (M-bonacci binomial coefficients). These are similar to the binomial and the Fibonomial (or Fibonacci-binomial) coefficients and can be displayed in a triangle similar to Pascal's triangle from which some identities become obvious.|

Asiru, Muniru A.

2010-01-01

83

A numerical study of some drag coefficients  

Microsoft Academic Search

Numerical calculations based on formulas established in some previous papers, especially those related to the expressions of the drag coefficients. The obstacle is a symmetrical wedge. The results are presented in the form of numerous tables and graphs (drag coefficient vs ratio of velocity at infinity upstream to free stream speed). The drag coefficient on the obstacle increases with the

S. Popp

1974-01-01

84

Soccer Ball Lift Coefficients via Trajectory Analysis  

ERIC Educational Resources Information Center

|We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin…

Goff, John Eric; Carre, Matt J.

2010-01-01

85

A Rank Correlation Coefficient Resistant to Outliers  

Microsoft Academic Search

In this article, a nonparametric correlation coefficient is defined that is based on the principle of maximum deviations. This new correlation coefficient, Rg, is easy to compute by hand for small to medium sample sizes. In comparing it with existing correlation coefficients, it was found to be superior in a sampling situation that we call “biased outliers,” and hence appears

Rudy A. Gideon; Robert A. Hollister

1987-01-01

86

Soccer Ball Lift Coefficients via Trajectory Analysis  

ERIC Educational Resources Information Center

We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin…

Goff, John Eric; Carre, Matt J.

2010-01-01

87

Turbulent diffusion coefficients of toroidal plasmas  

Microsoft Academic Search

The difussion coefficient of a plasma with density gradient-produced fluctuations was calculated. Two different methods of deriving the diffusion coefficients were used. Then, the condition that two methods yield the same result is used to determine the phase angle a between the density and the potential fluctuations. The result shows the pseudo-classical diffusion coefficients. Agreement with experimentally determined plasma confinement

S. Yoshikawa

1973-01-01

88

Random Coefficient Models: Theory and Applications  

Microsoft Academic Search

This paper provides an overview of the rationale behind, and the implementation, and uses of, the random coefficient approach to econometric modeling. A simple random coefficient model is presented, and methods for estimating, testing, and validating such a model are described. A more general model is then presented. The general model is shown to include several fixed-coefficient models as special

P. A. V. B. Swamy; George S. Tavlas

1995-01-01

89

High alpha Inlets.  

National Technical Information Service (NTIS)

The high alpha inlet research effort at Lewis is part of the High Alpha Technology Program (HATP) within NASA. A key goal of HATP is to develop concepts that provide a high level of control and maneuverability for high performance aircraft at low subsonic...

R. R. Burley B. H. Anderson C. F. Smith G. J. Harloff

1991-01-01

90

Stagnation point von Kármán coefficient.  

PubMed

On the basis of various direct numerical simulations (DNS) of turbulent channel flows the following picture is proposed. (i) At a distance y from either wall, the Taylor microscale lambda is proportional to the average distance l(s) between stagnation points of the fluctuating velocity field, i.e., lambda(y)=B(1)l(s)(y) with B(1) constant, for delta(nu) < y < or approximately equal to delta, where the wall unit delta(nu) is defined as the ratio of kinematic viscosity nu to skin friction velocity u(tau) and delta is the channel's half-width. (ii) The number density n(s) of stagnation points varies with height according to n(s)=(C(s)/delta(nu)(3))y(+)(-1) where y(+) identical with y/delta(nu) and C(s) is constant in the range delta(nu) < y < or approximately equal to delta. (iii) In that same range, the kinetic energy dissipation rate per unit mass, equals 2/3(E(+)((u(tau)(3)/kappa(s)y) where E(+) is the total kinetic energy per unit mass normalized by u(tau)(2) and kappa(s)=B(1)(2)/C(s) is the stagnation point von Kármán coefficient. (iv) In the limit of exceedingly large Reynolds numbers Re(tau) identical with delta/delta(nu), large enough for the Reynolds stress -(uv) to equal u(tau)(2) in the range delta(nu) < y < delta, and assuming that production of turbulent kinetic energy balances dissipation locally in that range and limit, the mean velocity U(+), normalized by u(tau), obeys (d/dy)U(+) approximately equal to 2/3(E(+)/kappa(s)y) in that same range. (v) It follows that the von Kármán coefficient kappa is a meaningful and well-defined coefficient and the log law holds in turbulent channel/pipe flows only if E(+) is independent of y(+) and Re(tau) in that range, in which case kappa approximately kappa(s). (vi) In support of (d/dy)U(+) approximately equal to 2/3(E(+)/kappa(s)y), DNS data of turbulent channel flows which include the highest currently available values of Re(tau) are best fitted by E(+) approximately equal to 2/3(B(4)y(+)(-2/15)) and (d/dy(+))U(+) approximately equal to (B(4)/kappa(s))y(+)(-1-2/15) with B4 independent of y in delta(nu) < y < delta if the significant departure from -(uv) approximately equal to u(tau)(2) at these Re(tau) values is taken into account. PMID:19905435

Dallas, V; Vassilicos, J C; Hewitt, G F

2009-10-06

91

Copolymers of Methyl Alpha-N-Alkylacrylate and Methyl Methacrylate.  

National Technical Information Service (NTIS)

This patent relates to methyl methacrylate and methyl alpha-n-alkylacrylate wherein the alkyl group, which may vary from 10 to 22 carbon atoms, copolymerize at about 50C in the presence of azobisisobutyronitrile to form polymers having low coefficients of...

H. Gisser H. E. Mertwoy

1976-01-01

92

Imaging alpha particle detector  

DOEpatents

A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

Anderson, D.F.

1980-10-29

93

Event counting alpha detector  

DOEpatents

An electrostatic detector for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure.

Bolton, Richard D. (Los Alamos, NM); MacArthur, Duncan W. (Los Alamos, NM)

1996-01-01

94

Analysis of fluorophore diffusion by continuous distributions of diffusion coefficients: application to photobleaching measurements of multicomponent and anomalous diffusion.  

PubMed Central

Fluorescence recovery after photobleaching (FRAP) is widely used to measure fluorophore diffusion in artificial solutions and cellular compartments. Two new strategies to analyze FRAP data were investigated theoretically and applied to complex systems with anomalous diffusion or multiple diffusing species: 1) continuous distributions of diffusion coefficients, alpha(D), and 2) time-dependent diffusion coefficients, D(t). A regression procedure utilizing the maximum entropy method was developed to resolve alpha(D) from fluorescence recovery curves, F(t). The recovery of multi-component alpha(D) from simulated F(t) with random noise was demonstrated and limitations of the method were defined. Single narrow Gaussian alpha(D) were recovered for FRAP measurements of thin films of fluorescein and size-fractionated FITC-dextrans and Ficolls, and multi-component alpha(D) were recovered for defined fluorophore mixtures. Single Gaussian alpha(D) were also recovered for solute diffusion in viscous media containing high dextran concentrations. To identify anomalous diffusion from FRAP data, a theory was developed to compute F(t) and alpha(D) for anomalous diffusion models defined by arbitrary nonlinear mean-squared displacement versus time relations. Several characteristic alpha(D) profiles for anomalous diffusion were found, including broad alpha(D) for subdiffusion, and alpha(D) with negative amplitudes for superdiffusion. A method to deduce apparent D(t) from F(t) was also developed and shown to provide useful complementary information to alpha(D). alpha(D) and D(t) were determined from photobleaching measurements of systems with apparent anomalous subdiffusion (nonuniform solution layer) and superdiffusion (moving fluid layer). The results establish a practical strategy to characterize complex diffusive phenomena from photobleaching recovery measurements.

Periasamy, N; Verkman, A S

1998-01-01

95

Gas-film coefficients for streams  

USGS Publications Warehouse

Equations for predicting the gas-film coefficient for the volatilization of organic solutes from streams are developed. The film coefficient is a function of windspeed and water temperature. The dependence of the coefficient on windspeed is determined from published information on the evaporation of water from a canal. The dependence of the coefficient on temperature is determined from laboratory studies on the evaporation of water. Procedures for adjusting the coefficients for different organic solutes are based on the molecular diffusion coefficient and the molecular weight. The molecular weight procedure is easiest to use because of the availability of molecular weights. However, the theoretical basis of the procedure is questionable. The diffusion coefficient procedure is supported by considerable data. Questions, however, remain regarding the exact dependence of the film coefficint on the diffusion coefficient. It is suggested that the diffusion coefficient procedure with a 0.68-power dependence be used when precise estimate of the gas-film coefficient are needed and that the molecular weight procedure be used when only approximate estimates are needed.

Rathbun, R. E.; Tai, D. Y.

1983-01-01

96

Impact ionization coefficients for electrons and holes in In0.14Ga0.86As  

Microsoft Academic Search

We report the measurement of impact ionization rates for electrons and holes in the direct band-gap semiconductor alloy In0.14Ga0.86As. Our results show clearly that the ionization rate for holes is greater than that for electrons. The measurments were made for electric fields between 2.6×105 and 3.4×105 V cm-1. In this range, the ionization coefficients can be expressed as alpha=alpha? exp(-A\\/E)

T. P. Pearsall; R. E. Nahory; M. A. Pollack

1975-01-01

97

Model for the variation upon doping of the isotope coefficient in high-{ital T}{sub {ital c}} superconductors  

SciTech Connect

A model, recently developed to study the competition between conventional BCS superconductivity and spin density waves in two-dimensional systems, is extended to study the variation of the isotope effect with the hole concentration. It is found that the isotope coefficient {alpha} varies abruptly near the hole concentration where the superconducting critical temperature is maximum. The isotope coefficient {alpha} varies from 0.80 to 0.04 in a narrow hole concentration range in qualitative agreement with experimental data for La{sub 2}CuO{sub 4}-based superconductors.

Yndurain, F. [Departamento de Fisica de la Materia Condensada, Universidad Autonoma de Madrid, 28049-Madrid (Spain)

1995-04-01

98

Rossi Alpha Method.  

National Technical Information Service (NTIS)

The Rossi Alpha Method has proved to be valuable for the determination of prompt neutron lifetimes in fissile assemblies having known reproduction numbers at or near delayed critical. This workshop report emphasizes the pioneering applications of the meth...

G. E. Hansen

1985-01-01

99

IMAGING AND MODELING RAPIDLY ROTATING STARS: {alpha} CEPHEI AND {alpha} OPHIUCHI  

SciTech Connect

We present submilliarcsecond resolution imaging and modeling of two nearby rapid rotators {alpha} Cephei and {alpha} Ophiuchi, obtained with the CHARA array-the largest optical/IR interferometer in the world. Incorporating a gravity-darkening model, we are able to determine the inclination, the polar and equatorial radius and temperature, as well as the fractional rotation speed of the two stars with unprecedented precision. The polar and equatorial regions of the two stars have {approx}2000 K temperature gradient, causing their apparent temperatures and luminosities to be dependent on their viewing angles. Our modeling allow us to determine the true effective temperatures and luminosities of {alpha} Cep and {alpha} Oph, permitting us to investigate their true locations on the H-R diagram. These properties in turn give us estimates of the masses and ages of the two stars within a few percent of error using stellar evolution models. Also, based on our gravity-darkening modeling, we propose a new method to estimate the masses of single stars in a more direct way through Vsin i measurements and precise geometrical constraint. Lastly, we investigate the degeneracy between the inclination and the gravity-darkening coefficient, which especially affects the modeling of {alpha} Oph. Although incorporating Vsin i has lifted the degeneracy to some extent, higher-resolution observations are still needed to further constrain the parameters independently.

Zhao, M.; Monnier, J. D. [University of Michigan, Astronomy Department, 941 Dennison Bldg, Ann Arbor, MI 48109-1090 (United States); Pedretti, E.; Thureau, N. [University of St. Andrews, Scotland (United Kingdom); Merand, A.; Ten Brummelaar, T.; McAlister, H.; Turner, N.; Sturmann, J.; Sturmann, L.; Goldfinger, P. J.; Farrington, C. [The CHARA Array, Georgia State University, CA (United States); Ridgway, S. T. [National Optical Astronomy Observatory, NOAO, Tucson, AZ (United States)], E-mail: mingzhao@umich.edu

2009-08-10

100

The derivation and interpretation of control coefficients.  

PubMed Central

1. Equations for control coefficients are derived by using a method that generates all the control coefficients for a system in a single procedure. This requires solving fewer simultaneous equations than an equivalent method based on 'control theorems'. 2. The interpretation of control coefficients is discussed: in particular, it is shown that these functions are unsatisfactory as measures of 'control' and are perhaps best used as a means of testing control theories (models).

Crabtree, B; Newsholme, E A

1987-01-01

101

Portable alpha spectrometer.  

PubMed

Many portable devices have been designed to detect ?-rays or alpha and beta particles. Most of the ?-particle detectors give the total count as a result, without identifying the radionuclides existing in the sample. The development of a device allowing rapid and straightforward ?-particle spectrometry would be very useful for detecting the radioactive contents of unknown samples. This work describes the construction of a portable device using silicon semiconductor detectors designed to rapidly detect and possibly identify alpha-emitting radionuclides. PMID:22405957

Martín Sánchez, A; de la Torre Pérez, J

2012-03-03

102

Precision Measurements of {alpha}s at HERA  

SciTech Connect

The precision measurements of the strong coupling constant, {alpha}s, and its energy-scale dependence carried out at HERA by the H1 and ZEUS Collaborations are reviewed. An average value of {alpha}-bars(MZ) = 0.1186 {+-} 0.0011 (exp.) {+-} 0.0050 (th.) is obtained from these measurements. The combined HERA determinations of the energy-scale dependence of {alpha}s clearly show the running of {alpha}s from jet data alone and are in agreement with the running of the coupling as predicted by QCD.

Glasman, Claudia [Universidad Autonoma de Madrid (Spain)

2005-10-06

103

Data analysis for Seebeck coefficient measurements.  

PubMed

The Seebeck coefficient is one of the key quantities of thermoelectric materials and routinely measured in various laboratories. There are, however, several ways to calculate the Seebeck coefficient from the raw measurement data. We compare these different ways to extract the Seebeck coefficient, evaluate the accuracy of the results, and show methods to increase this accuracy. We furthermore point out experimental and data analysis parameters that can be used to evaluate the trustworthiness of the obtained result. The shown analysis can be used to find and minimize errors in the Seebeck coefficient measurement and therefore increase the reliability of the measured material properties. PMID:23822373

de Boor, J; Müller, E

2013-06-01

104

Distribution coefficients of atenolol and sotalol.  

PubMed

The distribution coefficient (D) of atenolol is lower than that of sotalol, despite the latter's lower partition coefficient (P). Since D is the relevant quantity under physiological conditions, it is re-established that atenolol is in practice the more hydrophilic. Because of the common confusion between P and D which this case exemplifies, the relation between them is set out. PMID:6143796

Taylor, P J; Cruickshank, J M

1984-02-01

105

Betatron tune shifts and Laslett image coefficients  

SciTech Connect

The complicated expressions of betatron tune shifts in terms of Laslett image coefficients are explained. The expressions of image coefficients for a centered or off-centered beam inside an elliptical or rectangular vacuum chamber are gathered. Typos in earlier literature are corrected.

K. Y. Ng

2001-07-20

106

Diffusion coefficient of modern humans outcompeting Neanderthals.  

PubMed

A nonlinear mathematical model is used to describe Neanderthals extinction about 35,000 years before present. Using archaeological data, radiocarbon re-calibrate speed among others, we show that the diffusion coefficient describing Modern Humans spread corresponds to 1596 km(2)/yr. The model is well established since all archaeological parameters, including Neanderthal-Modern interaction coefficient, become estimated. PMID:21540038

Flores, J C

2011-04-17

107

Pictoral Representation of Kendall's Rank Correlation Coefficient  

NSDL National Science Digital Library

This article, created by D. Wilkie of Windscale-Cumbria, explains the method of determining Kendall's Rank correlation coefficient, z, by drawing lines between corresponding points in the two rankings. The entire lesson is based around a series of diagrams which help illustrate correlation coefficients.

Wilkie, D.

2009-03-10

108

Kendall's correlation coefficient for vague preferences  

Microsoft Academic Search

The problem of measuring association between preference systems in situations with missing information or noncomparable outputs\\u000a is discussed. New correlation coefficient, which generalizes Kendall’s correlation coefficients used traditionally in statistics,\\u000a is suggested. The construction utilizes IF-sets.

Przemyslaw Grzegorzewski

2009-01-01

109

Eddy diffusion coefficients in the lower thermosphere  

NASA Astrophysics Data System (ADS)

The seasonal variation of the eddy diffusion coefficient is deduced for a height of 94 km at 23 deg S based on two independent methods of analysis. One is related to indirect measurements of atomic oxygen and the other to measurements of the density of upper atmospheric sodium. The results are mutually consistent giving a maximum eddy diffusion coefficient during summer.

Kirchhoff, V. W. J. H.; Clemesha, B. R.

1982-08-01

110

A gain-coefficient switched Alexandrite laser  

NASA Astrophysics Data System (ADS)

We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

Lee, Chris J.; van der Slot, Peter J. M.; Boller, Klaus-J.

2013-01-01

111

First Townsend Ionization Coefficient in Hydrogen.  

National Technical Information Service (NTIS)

Rose's measurements of the first Townsend ionization coefficient N in hydrogen for E/p>100 V 1/(cm Torr) have been questioned by a number of authors principally either because of a supposed neglect of the second Townsend ionization coefficient G, or becau...

D. E. Golden H. Nakano L. H. Fisher

1965-01-01

112

Translational diffusion coefficient of cycloamylose in aqueous sodium hydroxide.  

PubMed

Seven cyclic (1 --> 4)-alpha-D-glucan (cycloamylose) samples ranging in weight-average molecular weight from 5 x 10(3) to 1.8 x 10(4) and gamma-cyclodextrin have been studied by sedimentation equilibrium in dimethylsulfoxide (at 25 degrees C) and by dynamic light scattering in 0.5 N aqueous sodium hydroxide (at 25 degrees C), a good solvent for linear amylose. The measured translational diffusion coefficients D in the aqueous NaOH agree fairly closely with previous Monte Carlo results for cyclic (1 --> 4)-alpha-D-glucan chains with excluded volume, when correction is made for the effects of bead diameter and fluctuating hydrodynamic interaction (HI) on the Kirkwood theory on which the computation of D was based. These D data are also explained almost quantitatively by Yamakawa and Fujii's expression for the associated KP ring (based on the Kratky-Porod wormlike chain) with the molecular parameters for linear amylose if the fluctuating HI and excluded-volume effects are taken into account. It is concluded that the translational diffusion behavior of cycloamylose in the aqueous NaOH is consistent with the conformational characteristics derived from the conformational energy of maltose and dilute-solution data for linear amylose. PMID:12879496

Nakata, Yasushi; Amitani, Keiji; Norisuye, Takashi; Kitamura, Shinichi

2003-08-01

113

Monte Carlo alpha calculation  

SciTech Connect

A Monte Carlo algorithm to efficiently calculate static alpha eigenvalues, N = ne/sup ..cap alpha..t/, for supercritical systems has been developed and tested. A direct Monte Carlo approach to calculating a static alpha is to simply follow the buildup in time of neutrons in a supercritical system and evaluate the logarithmic derivative of the neutron population with respect to time. This procedure is expensive, and the solution is very noisy and almost useless for a system near critical. The modified approach is to convert the time-dependent problem to a static ..cap alpha../sup -/eigenvalue problem and regress ..cap alpha.. on solutions of a/sup -/ k/sup -/eigenvalue problem. In practice, this procedure is much more efficient than the direct calculation, and produces much more accurate results. Because the Monte Carlo codes are intrinsically three-dimensional and use elaborate continuous-energy cross sections, this technique is now used as a standard for evaluating other calculational techniques in odd geometries or with group cross sections.

Brockway, D.; Soran, P.; Whalen, P.

1985-01-01

114

Alpha E beta 7.  

PubMed Central

alpha E beta 7 is a member of the integrin family and is expressed almost exclusively by cells of the T lymphocyte lineage in mucosal tissues. Expression is induced by transforming growth factor beta in the mucosal microenvironment. Genetic elements that control transcription are under investigation and may prove valuable for directing the expression of transgenes in mucosal T cells. The only known ligand for alpha E beta 7 is E-cadherin, which is expressed on epithelial cells. In this article, molecular aspects of ligand recognition by alpha E beta 7 in relation to recent structural data on cadherin domains are reviewed. Expression of alpha E beta 7 is often increased in inflammatory diseases, particularly where T cells infiltrate epithelial tissues. The function of alpha E beta 7 is not yet fully understood, but it is likely to be important in retention of T cells in mucosal tissues and may also have a role in cell signalling and communication between lymphocytes and epithelial surfaces.

Kilshaw, P J

1999-01-01

115

Nitric oxide reaction with lipid peroxyl radicals spares alpha-tocopherol during lipid peroxidation. Greater oxidant protection from the pair nitric oxide/alpha-tocopherol than alpha-tocopherol/ascorbate.  

PubMed

The reactions of nitric oxide ((.)NO) and alpha-tocopherol (alpha-TH) during membrane lipid oxidation were examined and compared with the pair alpha-TH/ascorbate. Nitric oxide serves as a more potent inhibitor of lipid peroxidation propagation reactions than alpha-TH and protects alpha-TH from oxidation. Mass spectrometry, oxygen and (.)NO consumption, conjugated diene analyses, and alpha-TH fluorescence determinations all demonstrated that (.)NO preferentially reacts with lipid radical species, with alpha-TH consumption not occurring until (.)NO concentrations fell below a critical level. In addition, alpha-TH and (.)NO cooperatively inhibit lipid peroxidation, exhibiting greater antioxidant capacity than the pair alpha-TH/ascorbate. Pulse radiolysis analysis showed no direct reaction between (.)NO and alpha-tocopheroxyl radical (alpha-T(.)), inferring that peroxyl radical termination reactions are the principal lipid-protective mechanism mediated by (.)NO. These observations support the concept that (.)NO is a potent chain breaking antioxidant toward peroxidizing lipids, due to facile radical-radical termination reactions with lipid radical species, thus preventing alpha-TH loss. The reduction of alpha-T(.) by ascorbate was a comparatively less efficient mechanism for preserving alpha-TH than (.)NO-mediated termination of peroxyl radicals, due to slower reaction kinetics and limited transfer of reducing equivalents from the aqueous phase. Thus, the high lipid/water partition coefficient of (.)NO, its capacity to diffuse and concentrate in lipophilic milieu, and a potent reactivity toward lipid radical species reveal how (.)NO can play a critical role in regulating membrane and lipoprotein lipid oxidation reactions. PMID:10753874

Rubbo, H; Radi, R; Anselmi, D; Kirk, M; Barnes, S; Butler, J; Eiserich, J P; Freeman, B A

2000-04-14

116

First townsend coefficient of organic vapour in avalanche counters  

NASA Astrophysics Data System (ADS)

A new concept is presented in the paper for implementing the proven method of determining the first Townsend coefficient (?) of gases using an avalanche counter. The A and B gas constants, interrelated by the expression ?/p = A exp[-B/(K/p)], are analyzed. Parallel-plate avalanche counters (PPAC) with an electrode spacing d from 0.1 to 0.4 cm have been employed for the investigation, arranged to register low-energy alpha particles at n-heptane vapour pressures of p >= 5 Torr. An in-depth discussion is given, covering the veracity and the behaviour vs K/p, of the n-heptane A and B constants determined at reduced electric-field intensity values ranging from 173.5 to 940 V/cm Torr; the constants have been found to depend upon d. The results of the investigation are compared to available data of the ? coefficient of organic vapours used in avalanche counters. The PPAC method of determining ? reveals some imperfections at very low values of the pd product.

Sernicki, Jan

1990-03-01

117

Estimation of Actual Response Coefficients in the Hildreth-Houck Random Coefficient Model  

Microsoft Academic Search

When the response coefficients in the general linear model are regarded as random variables, the mean of the distribution of these coefficients can be estimated using methods suggested by Hildreth and Houck. This article derives the minimum variance, linear, unbiased estimator for the actual response coefficients which were realized over the sample period. One might suspect that the best estimator

W. E. Griffiths

1972-01-01

118

Monte Carlo alpha deposition  

SciTech Connect

Prior work demonstrated the importance of nuclear scattering to fusion product energy deposition in hot plasmas. This suggests careful examination of nuclear physics details in burning plasma simulations. An existing Monte Carlo fast ion transport code is being expanded to be a test bed for this examination. An initial extension, the energy deposition of fast alpha particles in a hot deuterium plasma, is reported. The deposition times and deposition ranges are modified by allowing nuclear scattering. Up to 10% of the initial alpha particle energy is carried to greater ranges and times by the more mobile recoil deuterons. 4 refs., 5 figs., 2 tabs.

Talley, T.L.; Evans, F.

1988-01-01

119

Evaluating a modified exercise self-efficacy scale for college-age women.  

PubMed

This pilot study examined test-retest and internal consistency reliabilities of original and modified formats of the Exercise Self-efficacy Scale in college-age women. 30 completed original and modified versions of the scale. Data from both tests, administered 1 wk. apart, were analyzed using the intraclass correlation coefficient (ICC) to assess test-retest reliability and Cronbach coefficient alpha for internal consistency. Scores for both versions correlated .96. Cronbach coefficients alpha for the original scale were .96 for Time 1 and .98 for Time 2. Cronbach coefficients alpha for the revised scale were .95 for Time 1 and .98 for Time 2. Test-retest reliability and internal consistency remained consistently high for both versions of the scales within this sample. Implications for use of this scale and recommendations for research are given. PMID:17326499

Ornes, Lynne L; Ransdell, Lynda B; Pett, Marjorie A

2006-12-01

120

Soccer ball lift coefficients via trajectory analysis  

NASA Astrophysics Data System (ADS)

We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin parameters that have not been obtained by today's wind tunnels. Our trajectory analysis technique is not only a valuable tool for professional sports scientists, it is also accessible to students with a background in undergraduate-level classical mechanics.

Goff, John Eric; Carré, Matt J.

2010-07-01

121

Calculation of temperature coefficients for thermodynamic function  

NASA Astrophysics Data System (ADS)

Temperature coefficients for thermodynamic function are determined by means of a simultaneous least-squares fitting of heat-capacity, enthalpy, and entropy, which are described as polynomial equations in temperature. After some mathematical treatments and programming, exact numerical solutions can be obtained. The first and systematical calculation of the temperature coefficients for combustion products of the copper element has been completed. The function ensures the equal values at the cross point of the two temperature intervals. This method provides reliable data of the temperature coefficients for the calculation of propellant performance.

Tian, Deyu; Weng, Wujun; Liu, Zhengyuan

1991-04-01

122

Radon diffusion coefficients for residential concretes  

SciTech Connect

Radon gas diffusion through concrete can be a significant mechanism for radon entry into dwellings. Measurements of radon diffusion coefficients in the pores of residential concretes ranged from 2.1 x 10{sup {minus}8} m{sup 2} s{sup {minus}1} to 5.2 x 10{sup {minus}7} m{sup 2} s{sup {minus}1}. The pore diffusion coefficients generally increased with the water-cement ratio of the concrete and decreased with its density. A least-squares regression of the diffusion coefficients on concrete density gave an r value of -0.73. 16 refs., 2 figs., 3 tabs.

Rogers, V.C.; Nielson, K.K.; Holt, R.B. [Rogers and Associates Engineering Corp., Salt Lake City, UT (United States); Snoddy, R. [Acurex Environmental Corp., Research Triangle Park, NC (United States)

1994-09-01

123

Electron Avalanches in Oxygen and in Mixtures of O2 and H2: Determination of the First Townsend Coefficient.  

National Technical Information Service (NTIS)

Current transients of pre-breakdown electron avalanches in uniform fields in pure oxygen, and in mixtures of oxygen and hydrogen were studied. The goal of this work is to determine an effective first Townsend coefficient alpha, which accounts for instanta...

R. J. Corbin L. Frommhold

1974-01-01

124

Alpha-particle-induced cancer in humans.  

PubMed

Updated information is given on alpha-particle-induced cancer in persons internally exposed to 222Rn progeny, Thorotrast, long-lived 226Ra and 228Ra, and short-lived 224Ra. The lung cancer risk to persons breathing 222Rn progeny in the indoor air of offices, schools, and homes is of increasing concern. About half of the recent deaths among the German Thorotrast patients have been from liver cancer. Animal studies indicate that the liver cancer risk from Thorotrast is mainly from its radioactivity and that the risk coefficient for the Thorotrast patients can be used provisionally for other alpha emitters in the human liver. Six skeletal cancers have occurred in persons with average skeletal doses between 0.85 and 11.8 Gy from 226Ra and 228Ra. In the low-dose German 224Ra patients, two skeletal sarcomas have occurred at about 0.7 Gy compared to about six cases predicted by results from 224Ra patients at higher doses. The minimal appearance time for radiation-induced bone sarcomas in humans is about 4 y. Following brief irradiation, the vast majority of induced bone sarcomas are expressed by about 30 y. Recent evidence against the "practical threshold" hypothesis is given. With the downward revision of neutron doses to the atomic-bomb survivors, the follow-up of persons exposed to alpha particles may be the best opportunity to evaluate directly the effects of high LET radiation on humans. PMID:2844697

Mays, C W

1988-10-01

125

Hypoglycaemic activity of alpha, alpha trehalose-6-phosphate.  

PubMed

Alpha-alpha-trehalose-6-phosphate, synthesized by Oke was screened for hypoglycaemic activity. Alloxan-induced diabetic albino rats and fasted-rabbits were used in the study. The inhibitory activity of trehalose-6-phosphate on trehalase was also assayed. The study shows that alpha-alpha-trehalose-6-phosphate is a glucose analogue with potent anti-hyperglcaemic activity as shown by its hypoglycaemic response in fasted rabbits. The ability of alpha-alpha-trehalose-6-phosphate to attenuate the diabetic toxicity in alloxan-induced diabetic rats confirmed its potent anti-diabetic activity. The mechanism of action of this synthesized compound may be linked with its ability to inhibit trehalase, and increase the activity of the superoxidase dimutase present in the beta-cells of the alloxan-diabetic rats and also being a glucose analogue according to Puls principle, alpha-alpha-trehalose-6-phosphate is able to influence the intermediate metabolism of carbohydrate. PMID:10497653

Oke, J M; Watt, R A

126

Rossi Alpha Method  

Microsoft Academic Search

The Rossi Alpha Method has proved to be valuable for the determination of prompt neutron lifetimes in fissile assemblies having known reproduction numbers at or near delayed critical. This workshop report emphasizes the pioneering applications of the method by Dr. John D. Orndoff to fast-neutron critical assemblies at Los Alamos. The value of the method appears to disappear for subcritical

1985-01-01

127

Alpha-mannosidosis  

Microsoft Academic Search

Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are

Dag Malm; Øivind Nilssen

2008-01-01

128

Structure of alpha Gete.  

National Technical Information Service (NTIS)

The parameters in the crystal structure of alpha-GeTe were determined by least-squares analysis of intensity data obtained with an automatic x-ray powder diffractometer. The rhombohedral cell containing 4 Ge and 4 Te atoms has a=5.996 plus or minus 0.001 ...

J. Goldak C. S. Barrett D. Innes W. Youdelis

1965-01-01

129

[alpha]-Oxocarboxylic Acids  

ERIC Educational Resources Information Center

|Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH…

Kerber, Robert C.; Fernando, Marian S.

2010-01-01

130

Factors affecting miscible flooding dispersion coefficients  

SciTech Connect

Miscible solvent slug size, and therefore cost, is dependent on the mixing or dispersion taking place in the reservoir. Fluid mixing also can be important in the interpretation of laboratory simulations of miscible floods. An experimental program was conducted to study the effects of velocity, viscosity ratio, rock type, and core length on dispersion (mixing) coefficients measured in short cores, with the objective of scaling laboratory measurements to field systems. Statistical analysis of the results of the tests, matched with the capacitance-dispersion (dead-end pore volume) model, shows that an effective dispersion coefficient derived from the model is the most consistent measure of mixing in the systems studied. Viscosity ratios differing by + 4% from unity had no significant effect on the effective dispersion coefficient. The effect of system length on the effective dispersion coefficient is shown.

Yellig, W.F.; Baker, L.E.

1980-01-01

131

Static Coefficient Test Method and Apparatus.  

National Technical Information Service (NTIS)

A method and apparatus is described for determining the static coefficient of friction between contacting surfaces of a plurality of bodies. A flexible filament fixedly connected to one of the bodies is alternately and cyclically tensioned and relaxed in ...

C. L. Haehner J. L. Tarpley

1975-01-01

132

Network community structure and loop coefficient method  

NASA Astrophysics Data System (ADS)

A modular structure, in which groups of tightly connected nodes could be resolved as separate entities, is a property that can be found in many complex networks. In this paper, we propose a algorithm for identifying communities in networks. It is based on a local measure, so-called loop coefficient that is a generalization of the clustering coefficient. Nodes with a large loop coefficient tend to be core inner community nodes, while other vertices are usually peripheral sites at the borders of communities. Our method gives satisfactory results for both artificial and real-world graphs, if they have a relatively pronounced modular structure. This type of algorithm could open a way of interpreting the role of nodes in communities in terms of the local loop coefficient, and could be used as a complement to other methods.

Vragovi?, I.; Louis, E.

2006-07-01

133

Dynamic Formulation of Coefficient of Restitution.  

National Technical Information Service (NTIS)

The paper is concerned with the preparation of a mathematical model involving collisions between two bodies and the subsequent analog computer program. It considers a fictitious damped spring as a coefficient of restitution generator'. Formulae are derive...

E. H. Jakubowski

1964-01-01

134

Geoid Representation from Satellite-Determined Coefficients.  

National Technical Information Service (NTIS)

This report describes the mathematical formulations and programs developed to provide a spatial representation of a geopotential surface, based on a set of geopotential harmonic coefficients determined by an investigator from a study of satellite motion. ...

A. R. LeSchack

1966-01-01

135

More Inaccurate Specifications of Ballistic Coefficients.  

National Technical Information Service (NTIS)

A ballistic coefficient (BC) can be determined by using two chronographs a measured distance away from each other and shooting a bullet so the velocity is measured by the two devices. Ballistic modeling software requires accurate measurement of ballistic ...

A. Halloran C. Demers C. Huntsman M. Courtney

2012-01-01

136

Heat transfer coefficient of cryotop during freezing.  

PubMed

Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K). PMID:23812315

Li, W J; Zhou, X L; Wang, H S; Liu, B L; Dai, J J

2013-01-01

137

Backward stochastic differential equations with continuous coefficient  

Microsoft Academic Search

We prove the existence of a solution for “one dimensional” backward stochastic differential equations where the coefficient is continuous, it has a linear growth, and the terminal condition is squared integrable. We also obtain the existence of a minimal solution.

J. P. Lepeltier; J. San Martin

1997-01-01

138

Transport coefficients of quark-gluon plasma  

Microsoft Academic Search

Transport coefficients of quark-gluon plasma are discussed in the framework of relativistic kinetic theory with the relaxation\\u000a time approximation of Boltzmann transport equation. The expressions for the coefficients of shear and volume viscosities and\\u000a heat conductivity are derived assuming quark-gluon plasma to be a non-reactive mixture of quarks, anti-quarks and gluons.\\u000a A lowest order in deviations from local thermal equilibrium

S. Chakrabarty

1985-01-01

139

Attenuation coefficients of Rayleigh and Lg waves  

Microsoft Academic Search

Analysis of the frequency dependence of the attenuation coefficient leads to significant changes in interpretation of seismic\\u000a attenuation data. Here, several published surface-wave attenuation studies are revisited from a uniform viewpoint of the temporal\\u000a attenuation coefficient, denoted by ?. Theoretically, ?( f) is expected to be linear in frequency, with a generally non-zero intercept ??=??(0) related to the variations of

Igor B. Morozov

2010-01-01

140

Viscosity coefficients of nematic hard particle fluids  

NASA Astrophysics Data System (ADS)

Enskog kinetic theory is applied to the calculation of the Miesowicz viscosities and the Leslie coefficients of a nematic liquid crystal comprised of hard ellipsoidal particles. The anisotropies in the calculated viscosities are consistent with those derived from computer simulation, affine transformation theory and from experiment. When the Miesowicz viscosities are combined with the diffusion coefficients for a nematic, approximate Stokes-Einstein relations are found.

Evans, Glenn T.

1998-01-01

141

Investigation of photon attenuation coefficients for marble.  

PubMed

The total linear attenuation coefficients micro (cm(-1)) have been obtained using the XCOM program at photon energies of 1 keV to 1 GeV for six different natural marbles produced in different places in Turkey. The individual contribution of photon interaction processes to the total linear attenuation coefficients for marble has been investigated. The calculated results were also compared with the measurements. The results obtained for marble were also compared with concrete. PMID:15942062

Basyigit, C; Akkurt, I; Kilincarslan, S; Akkurt, A

2005-06-07

142

Eddy diffusion coefficients in the lower thermosphere  

NASA Astrophysics Data System (ADS)

The seasonal variation of the eddy diffusion coefficient is deduced for a height of 94 km at 23 deg S on the basis of two independent methods of analysis. One of these methods, already used in the past, is related to indirect measurements of atomic oxygen, and the other one is a new method related to measurements of the density of upper atmospheric sodium. The results are mutually consistent, giving a maximum eddy diffusion coefficient during summer.

Kirchhoff, V. W. J. H.; Clemesha, B. R.

1983-07-01

143

Trace element distribution coefficients in alkaline series  

Microsoft Academic Search

Mineral\\/groundmass partition coefficients for U, Th, Zr, Hf, Ta, Rb, REE, Co and Sc have been systematically measured in olivine, clinopyroxene, amphibole, biotite, Ti-magnetites, titanite, zircon and feldspars, in basaltic to trachytic lavas from alkaline series (Velay, Chaîne des Puys: Massif Central, France and Fayal: Azores). Average partition coefficients are denned within the experimental uncertainty for limited compositional ranges (basalt-hawaiite,

Fabienne Lemarchand; Benoît Villemant; Georges Calas

1987-01-01

144

Experimental constraints on coefficients of (alpha)(sub s)-expansion of Gottfried sum rule.  

National Technical Information Service (NTIS)

The x- and Q(sup 2)-dependences of the Gottfried sum rule S(sub G)(x,Q(sup 2)) based on the experimental data on proton and deuteron structure functions are studied. The dependence of S(sub G)(x,Q(sup 2)) on Q(sup 2) for low x points to flavour asymmetry ...

A. V. Sidorov M. V. Tokarev

1996-01-01

145

Pressure effects on the alpha and alpha' relaxations in polymethylphenylsiloxane  

Microsoft Academic Search

In some polymers, in addition to the usual structural alpha relaxation, a slower alpha' relaxation is observed with a non-Arrhenius temperature dependence. In order to understand better the molecular origin of this alpha' relaxation in poly(methylphenylsiloxane) (PMPS) we have studied, for the first time, the pressure dependence of its relaxation time, together with the usual temperature dependence, by means of

H. Kriegs; J. Gapinski; G. Meier; M. Paluch; S. Pawlus; A. Patkowski

2006-01-01

146

Alpha-1 Antitrypsin Deficiency: Inherited Liver Disease  

MedlinePLUS

... View full profile Alpha-1 Antitrypsin Deficiency: Inherited Liver Disease The inherited condition alpha-1 antitrypsin deficiency can cause liver disease in children and adults. Alpha-1 antitrypsin ...

147

Alpha Numeric Symbol Generation Equipment.  

National Technical Information Service (NTIS)

Hazeltine has developed and installed two Alpha Numeric Generator equipments in the FAA Atlanta and Indianapolis Air Traffic Control Centers. These equipments have passed all acceptance tests and are undergoing operation testing. These Alpha Numeric Gener...

J. F. O'Connor

1965-01-01

148

Alpha Numeric Symbol Generation Equipment.  

National Technical Information Service (NTIS)

Two Alpha Numeric Generator equipments in the FAA Atlanta and Indianapolis Air Traffic Control Centers passed all acceptance tests and are undergoing operation testing. These Alpha Numeric Generators electronically label aircraft radar blips on air traffi...

J. F. O'Connor

1965-01-01

149

Summary of Alpha Particle Transport  

SciTech Connect

This paper summarizes the talks on alpha particle transport which were presented at the 5th International Atomic Energy Agency's Technical Committee Meeting on "Alpha Particles in Fusion Research" held at the Joint European Torus, England in September 1997.

Medley, S.S.; White, R.B.; Zweben, S.J.

1998-08-19

150

Gamma-Ray-Multiplicity Measurements for (alpha,p), (alpha,alpha'), (d,alpha), (p,alpha), (d,p), and (p,p') Reactions  

Microsoft Academic Search

Using a method introduced previously measurements were made of the gamma-ray multiplicity Ngamma (the average number of gamma rays emitted in the decay of residual nuclei left by nuclear reactions) as a function of excitation energy E* for (p,alpha) and (d,alpha) reactions on 51V, 56Fe, and 57Fe targets; (alpha,p) reactions on 51V, 56Fe, 57Fe, 58Ni, 64Ni, 93Nb, and Ag; (alpha,alpha')

J. H. Degnan; B. L. Cohen; G. R. Rao; K. C. Chan; L. Shabason

1973-01-01

151

AlphaGalileo  

NSDL National Science Digital Library

Billed as "The world's leading resource for European research", AlphaGalileo is a tremendous resource for those with a penchant for keeping tabs on Continental scholarship that deals with science, art, technology, health, society, and the humanities. The team at AlphaGalileo includes a multilingual group of specialists and their coverage is very broad, a fact that will be welcomed in many quarters. Visitors need to complete a brief registration before using the site, and after that they can browse and search through the materials offered here. The site also allows users to perform thematic searches and the opportunity to look over press releases. It's also worth noting that after logging in, visitors can also post their own items.

152

Experimental kerma coefficients of biologically important materials at neutron energies below 75 MeV.  

PubMed

The present work summarizes our results already published on cross sections and partial kerma coefficients for hydrogen, carbon, and oxygen and then applies them for determining experimental partial and total kerma coefficients of composite biologically important materials. Double-differential cross sections for light-charged particle production (proton, deuteron, triton, and alpha particle) induced by fast neutrons on hydrogen, carbon, and oxygen have been experimentally measured at several incident energies from 25 to 75 MeV. The measurements covered the laboratory angular range 20 degrees to 160 degrees and were extended to very forward and very backward angles by using a reliable extrapolation procedure. Energy-differential, angle-differential, and total production cross sections were derived from the measured data. The experimental methods and data reduction procedures are briefly presented here. The experimental cross sections were compared to existing data in the literature for nucleon-induced reactions and against prediction of nuclear models. Partial and total elemental kerma coefficients were deduced on the basis of the measured cross sections. Procedures for extrapolating the partial kerma coefficients down to the reaction threshold energies for each of the measured ejectile species have been applied to carbon and oxygen. A simple-to-use analytical formula to describe the experimental hydrogen kerma coefficients was proposed which provides the recoil kerma coefficients in the incident neutron energy range 0.3 to 100 MeV. The present article reports for the first time experimental partial kerma coefficients for composite materials of biological interest. Resulting total kerma coefficients are compared to theoretical predictions and to other experimental data. PMID:11128307

Meulders, J P; Benck, S; Slypen, I; Corcalciuc, V

2000-11-01

153

Prediction of alpha factor values for fine pore aeration systems.  

PubMed

The objective of this work was to analyse the impact of different geometric and operating parameters on the alpha factor value for fine bubble aeration systems equipped with EPDM membrane diffusers. Measurements have been performed on nitrifying plants operating under extended aeration and treating mainly domestic wastewater. Measurements performed on 14 nitrifying plants showed that, for domestic wastewater treatment under very low F/M ratios, the alpha factor is comprised between 0.44 and 0.98. A new composite variable (the Equivalent Contact Time, ECT) has been defined and makes it possible for a given aeration tank, knowing the MCRT, the clean water oxygen transfer coefficient and the supplied air flow rate, to predict the alpha factor value. ECT combines the effect on mass transfer of all generally accepted factors affecting oxygen transfer performances (air flow rate, diffuser submergence, horizontal flow). PMID:18469400

Gillot, S; Héduit, A

2008-01-01

154

Transport coefficients of soft sphere fluids.  

PubMed

This study explores the effects of interaction softness on the transport properties of simple fluids in which the particles interact via the potential, phi(r) = epsilon(r/sigma)(-n), with n in the range 6-1152. Molecular dynamics simulation has been used to compute the self-diffusion coefficient, D, the shear viscosity eta(s), bulk viscosity eta(b), and the thermal conductivity, lambda, over a wide packing fraction range. A number of semi-empirical formulae for these transport coefficients have been tested against this data. It was found that the transport coefficients were proportional to the exponential of the two-body component of the entropy. The quality of agreement was best for D and worst for the thermal conductivity. A cell model for the fluid based on the simulated mean square force was not successful in correlating the diffusion coefficient data over the wide range of n. We also consider several variants on the Stokes-Einstein relationship, which provide an informative insight into the global behaviour of (mainly) the self-diffusion coefficient and shear viscosity. PMID:19791336

Heyes, D M; Bra?ka, A C

2005-03-21

155

ALPHA SPILLOVER DEPENDS ON ALPHA ENERGY: A NEW FINDING IN ALPHA\\/BETA LIQUID SCINTILLATION SPECTROMETRY  

Microsoft Academic Search

The calibration of the alpha\\/beta liquid scintillation (LS) spectrometric measurement is rather complicated for samples having variable chemical and radionuclide compositions if rather accurate results are required. Variable quenching can be a significant source of uncertainty if it is not considered in the calibrations because variable quenching affects alpha and beta spillovers, the optimum pulse-shape analyzer (PSA), and alpha and

Laina Salonen

156

Understanding correlation coefficients in treaty verification  

SciTech Connect

When a pair of images are compared on a point-by-point basis, the linear-correlation coefficient is usually used as a measure of similarity or dissimilarity. This paper evaluates the theoretical underpinnings and limitation of the linear-correlation coefficient, as well as other related statistics, particularly for cases where inherent white noise is present. As a result of the limitations in linear-correlation, an additional step has been derived -- local-sum clustering -- in order to improve recognition of small dissimilarities in a pair images. Results show that three-stage procedure, consisting of first establishing congruence of the two images, than using the linear-correlation coefficient as a test of true negatives, and finally qualifying a true positive by using the cluster (local-sum) method. These algorithmic stages would be especially useful in arms control treaty verification.

DeVolpi, A.

1991-11-01

157

First results of Soret Coefficient Measurement Experiment  

NASA Astrophysics Data System (ADS)

The scope of the Soret Coefficient Measurement Experiment (SCM) is to measure the Soret coefficient in 20 binary organic mixtures and aqueous solutions. Because of the limited mass and power budget, this can be considered as a difficult technical challenge. It has been performed in the Solution Growth Facility in non fully nominal conditions and this has an impact on the accuracy of the measurements obtained as discussed in this presentation. However, the high values obtained for the species segregation in microgravity give very valuable results. They allow for a better understanding of ground based measurements and a definition, using the SCM results as standards, of the best technique to be used. The values of the Soret coefficients will be used in the investigation of the role of the Soret effect in interfacial instabilities (Marangoni-Benard instabilities in binary mixtures), on morphological instabilities of a planar solidification front and striations and on the buoyancy induced instabilities (Rayleigh-Benard instabilities).

van Vaerenbergh, St.; Legros, J.-Cl.; Dupin, J.-Ch

1995-08-01

158

Estimating Ordinal Reliability for Likert-Type and Ordinal Item Response Data: A Conceptual, Empirical, and Practical Guide  

ERIC Educational Resources Information Center

|This paper provides a conceptual, empirical, and practical guide for estimating ordinal reliability coefficients for ordinal item response data (also referred to as Likert, Likert-type, ordered categorical, or rating scale item responses). Conventionally, reliability coefficients, such as Cronbach's alpha, are calculated using a Pearson…

Gadermann, Anne M.; Guhn, Martin; Zumbo, Bruno D.

2012-01-01

159

The Adolescent Sexual Interest Card Sort: Test-retest reliability and concurrent validity in relation to phallometric assessment  

Microsoft Academic Search

Test—retest reliability and concurrent validity studies on the Adolescent Sexual Interest Card Sort (ASIC) were conducted in two samples of 38 juvenile sexual offenders, each. Of the 64 items of the ASIC, 60 were found to be significantly correlated across test administrations. Cronbach's coefficient alpha was employed to determine the internal consistency of ASIC items. Coefficients ranged from .62 to

John A. Hunter; Judith V. Becker; Meg S. Kaplan

1995-01-01

160

The escape of Lyman-alpha radiation from a multiphase interstellar medium  

Microsoft Academic Search

The Eddington approximation is used to model the transfer of radiation within a multiphase scattering medium. An estimate is thereby derived for the fraction of H Ly-alpha photons that escape from a galaxy with a two-phase interstellar medium in which dusty gas clouds lie embedded within an intercloud medium of negligible absorption and scattering coefficients. Under suitable conditions, Ly-alpha photons

David A. Neufeld

1991-01-01

161

The Subthreshold Autism Trait Questionnaire (SATQ): Development of a Brief Self-Report Measure of Subthreshold Autism Traits  

Microsoft Academic Search

The current study was motivated by a need for a self-report questionnaire that assesses a broad range of subthreshold autism\\u000a traits, is brief and easily administered, and is relevant to the general population. An initial item pool was administered\\u000a to 1,709 students. Structural validity analysis resulted in a 24-item questionnaire termed the Subthreshold Autism Trait Questionnaire\\u000a (SATQ; Cronbach’s alpha coefficient = .73,

Stephen M. Kanne; Jennifer Wang; Shawn E. Christ

162

A Reliability Generalization of the Overexcitability Questionnaire–Two  

Microsoft Academic Search

Reliability generalization (RG) is a meta-analysis that combines and synthesizes reliability coefficients from different studies to ascertain the average observed reliability across studies. An RG study was conducted on previously reported data from 16 samples of the Overexcitability Questionnaire–Two (OEQII) with a combined N of 5,275. Cronbach’s alpha was found to be consistently higher on all OEQII subscales when scale

Russell T. Warne

2011-01-01

163

Pressure effects on the alpha and alpha' relaxations in polymethylphenylsiloxane.  

PubMed

In some polymers, in addition to the usual structural alpha relaxation, a slower alpha' relaxation is observed with a non-Arrhenius temperature dependence. In order to understand better the molecular origin of this alpha' relaxation in poly(methylphenylsiloxane) (PMPS) we have studied, for the first time, the pressure dependence of its relaxation time, together with the usual temperature dependence, by means of dynamic light scattering (DLS). For the same material the alpha relaxation was also studied by means of DLS and dielectric spectroscopy (DS) in broad temperature and pressure ranges. We find that the temperature dependence of both alpha and alpha' relaxation times, at all pressures studied, can be described by a double Vogel-Fulcher-Tammann (VFT) law. The pressure dependence of the characteristic temperatures Tg (glass transition temperature) and T0 (Vogel temperature) as well as the activation volumes for both alpha and alpha' processes are very similar, indicating, that both relaxation processes originate from similar local molecular dynamics. Additionally, for both alpha and alpha' relaxations the combined temperature and pressure dependences of the relaxation times can be described using a parameter Gamma=rhon/T with the same value of the exponent n. PMID:16542098

Kriegs, H; Gapinski, J; Meier, G; Paluch, M; Pawlus, S; Patkowski, A

2006-03-14

164

Generalized QRT mappings with periodic coefficients  

NASA Astrophysics Data System (ADS)

We present an extension of the QRT mapping beyond the familiar symmetric and asymmetric varieties. Starting from our results on discrete Painlevé equations, we show that there exist integrable QRT-like mappings, the coefficients of which are periodic functions. We present several examples of mappings with periodic coefficients of various periods and show that there exist cases where the periods are arbitrarily long. We prove the integrability of all the examples by constructing the corresponding conserved quantities and we show how these systems, just as their QRT siblings, can be explicitly integrated in terms of elliptic functions.

Ramani, A.; Grammaticos, B.; Willox, R.

2011-01-01

165

Supersymmetric contributions to weak decay correlation coefficients  

NASA Astrophysics Data System (ADS)

We study supersymmetric contributions to correlation coefficients that characterize the spectral shape and angular distribution for polarized ?- and ?-decays. In the minimal supersymmetric standard model (MSSM), one-loop box graphs containing superpartners can give rise to non-(V-A)?(V-A) four-fermion operators in the presence of left-right or flavor mixing between sfermions. We analyze the present phenomenological constraints on such mixing and determine the range of allowed contributions to the weak decay correlation coefficients. We discuss the prospective implications for future ?- and ?-decay experiments, and argue that they may provide unique probes of left-right mixing in the first generation scalar fermion sector.

Profumo, S.; Ramsey-Musolf, M. J.; Tulin, S.

2007-04-01

166

Coefficient of restitution as a fluctuating quantity.  

PubMed

The coefficient of restitution of a spherical particle in contact with a flat plate is investigated as a function of the impact velocity. As an experimental observation we notice nontrivial (non-Gaussian) fluctuations of the measured values. For a fixed impact velocity, the probability density of the coefficient of restitution, p(?), is formed by two exponential functions (one increasing, one decreasing) of different slope. This behavior may be explained by a certain roughness of the particle which leads to energy transfer between the linear and rotational degrees of freedom. PMID:22181134

Montaine, Marina; Heckel, Michael; Kruelle, Christof; Schwager, Thomas; Pöschel, Thorsten

2011-10-21

167

Gasser-Leutwyler coefficients: A progress report  

NASA Astrophysics Data System (ADS)

Last year, we reported our first results on the determination of Gasser-Leutwyler coefficients using partially quenched lattice QCD with three flavors of dynamical staggered quarks. We give an update on our progress in determining two of these coefficients, including an exhaustive effort to estimate all sources of systematic error. At this conference, we have heard about algorithmic techniques to reduce staggered flavor symmetry breaking and a method to incorporate staggered flavor breaking into the partially quenched chiral Lagrangian. We comment on our plans to integrate these developments into our ongoing program.

Fleming, George T.; Nelson, Daniel R.; Kilcup, Gregory W.

2003-05-01

168

Diffusion and transport coefficients in synthetic opals  

SciTech Connect

Opals are structures composed of close-packed spheres in the size range of nano to micrometers. They are sintered to create small necks at the points of contact. We have solved the diffusion problem in such structures. The relation between the diffusion coefficient and the thermal and electrical conductivity is used to estimate the transport coefficients of opal structures as a function of the neck size and the mean free path of the carriers. The theory presented is also applicable to the diffusion problem in other periodic structures. (c) 2000 The American Physical Society.

Sofo, J. O. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, (8400) Bariloche RN, (Argentina); Mahan, G. D. [Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6030 (United States); Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200 (United States)

2000-07-15

169

Calculation of surface tension temperature coefficients  

SciTech Connect

In three previous communications the relationship between bulk properties and the surface tension of liquid metals and alloys was demonstrated. The surface tension of liquid metals was correlated with plasma frequency. It was then shown that the surface tension of liquid metals as well as alloys could be obtained from the bulk modulus and most recently a method was given for predicting the surface tension from the plasma frequency of the constituents of a binary alloy. The purpose of the present communication is to show that the temperature coefficient of surface tension of liquid metals may be calculated from another bulk property - the bulk coefficient of thermal expansion.

Papazian, H.A.

1984-12-01

170

alpha-Capture and alpha-elastic scattering on P-nuclei to probe the Hauser-Feshbach framework  

NASA Astrophysics Data System (ADS)

The thirty five neutron deficient stable nuclei known as the p-nuclei are synthesized in a series of photodisintegration reactions of the (gamma,n), (gamma,p) and (gamma,alpha) type in a hot gamma-flux environment. Abundance calculations involve an extended network of about 20,000 nuclear reactions of almost 2000 nuclei. The bulk of these rates are calculated theoretically with the statistical Hauser Feshbach Model (HF Model). Of particular importance in the p-process modeling are the (gamma,alpha) branchings. Even though in the astrophysical environment it is photodisintegration reactions that synthesize the p-nuclei, in the laboratory it is the inverse process that is generally measured. By detailed balance, it is possible to arrive at the relevant reactions. The experimental data for alpha-capture reactions is scarce since at the p-process temperatures (2-3 GK), the alpha-particle energies are typically of a few MeV and the corresponding cross sections very small. In addition, the results show a significant deviation compared to the model predictions. The HF cross sections are governed by transmission coefficients. These are extracted from an appropriate optical model potential (OMP). The alpha-nucleus potential in particular is poorly known at low energies mainly due to the lack of relevant data. The observed inconsistencies between the predicted and measured (alpha,gamma) rates may be due to problems with this alpha-potential parameter. To explore the applicability of the Hauser Feshbach model, to extend the experimental database of alpha-capture reactions on p-nuclei, to test the global parameterizations that currently exist, and to constrain the alpha-nucleus potential, the alpha-capture cross section of 106Cd(alpha,gamma)110Sn and the local alpha-nucleus potentials of 106Cd, 118Sn, and 120,124,126,128,130 Te have been measured and extracted. The experiments have been carried out at the University of Notre Dame. The results are presented here.

Palumbo, Annalia

2009-11-01

171

Factor Scores, Structure Coefficients, and Communality Coefficients: It's All One General Linear Model.  

ERIC Educational Resources Information Center

|This paper explains the meaning and use of three important factor analytic statistics: factor scores, factor structure coefficients, and communality coefficients. For the discussion, 301 observations of junior high school students 11 measured variables from a previous study are analyzed. While factors provide the researcher with general…

Marsh, S. Neil

172

Osmotic Coefficients and Mean Activity Coefficients of Uni-univalent Electrolytes in Water at 25°C  

Microsoft Academic Search

This paper gives values for the osmotic coefficients and mean activity coefficients of uni-univalent electrolytes in aqueous solutions at 25 °C. The values are expressed on the molality or weight basis. The data available in the literature have been corrected to the presently accepted scales of atomic weights (1969) and temperature (IPST 1968) and, where necessary, to the absolute electrical

Walter J. Hamer; Yung-Chi Wu

1972-01-01

173

A method for determining valve coefficient and resistance coefficient for predicting gas flowrate  

Microsoft Academic Search

A method is introduced to determine the valve flow coefficient and resistance coefficient with the experiment of air discharging from a reservoir, and with the least squares method to fit the cumulative molar quantities discharged. The test valve is an angle-seat valve (Type 2632, Bürkert) with different apertures. At pressure difference of about 6bar, the choked flow occurs when the

Chunxia Long; Jianyu Guan

2011-01-01

174

Collapsibility of regression coefficients and its extensions  

Microsoft Academic Search

Collapsibility with respect to a measure of association implies that the measure of association can be obtained from the marginal model. We first discuss model collapsibility and collapsibility with respect to regression coefficients for linear regression models. For parallel regression models, we give simple and different proofs of some of the known results and obtain also certain new results. For

P. Vellaisamy; V. Vijay

2008-01-01

175

Structure Coefficients for Use in Stellar Analysis  

NASA Astrophysics Data System (ADS)

We give new values of the structural coefficients ?j, and related quantities, for realistic models of distorted stars in close binary systems. Our procedure involves numerical integration of Radau's equation for detailed structural data for stellar models taken from the EZWeb compilation of the Department of Astronomy, University of Wisconsin-Madison.

Inlek, Gulay; Budding, Edwin

2012-04-01

176

APPRAISAL OF SEASONAL VARIATION IN PAN COEFFICIENTS  

Microsoft Academic Search

SUMMARY The purpose ot this paper is to clarify the application of pan evaporation coeffi­ cients to obtain estimates of lake evaporation. Reliable estimates of annual lake evaporation may usually be obtained by use of annual pan evaporation and the appropriate pan coefficient. It is more difficult to derive accurate monthly values of lake evaporation from monthly pan evaporation data.

Tor J. NORDENSON

177

The Lorenz Curve and the Gini Coefficient.  

ERIC Educational Resources Information Center

States that the Lorenz Curve and the Gini Coefficient is a Web-based interactive tutorial developed for students in an upper level, undergraduate, elective economics course about income and wealth distribution, poverty, and discrimination. States that students achieve mastery because they cannot complete the tutorial without adequate understanding…

Rycroft, Robert

2003-01-01

178

Particle approach to the Fresnel coefficients  

Microsoft Academic Search

The Fresnel reflectivity and transmissivity coefficients for a semi-infinite medium are derived for normal and oblique incidence using a particle approach and a probabilistic condition at the boundary. The method depends in part on the behavior of the momentum of light in ordinary refractive media, and this subject is discussed. The method clarifies why the Schrödinger equation for the comparable

Frank R. Tangherlini

1975-01-01

179

Temperature coefficient of pyrographite surface free energy  

Microsoft Academic Search

By measuring the change in geometric parameters of cracks formed as a ; result of annealing, using the mathematical method of I. V. Obreimov, the ; temperature coefficient of free surface energy of basic-density pyrographite was ; measured in the interval 20 to 2300 deg C. (tr-auth);

V. I. Kostikov; A. G. Kharitonov

1972-01-01

180

Multiphase Composite PTC (Positive Temperature Coefficient) Thermistors.  

National Technical Information Service (NTIS)

Carbon black/polyethylene composite thermistors exhibiting a positive temperature coefficient (PTC) of resistance anomaly measuring 6-8 orders of magnitude (at 1kHz) were produced. To maintain high temperature stability, prevent the onset of an Negative T...

L. L. Rohlfing R. E. Newnham S. M. Pilgrim J. Runt

1988-01-01

181

EXAMINATION OF SCALE-DEPENDENT DISPERSION COEFFICIENTS  

EPA Science Inventory

Many hydrologists have observed that dispersion coefficients, when measured in the field, turn out to be scale-dependent. Recently, Guven, et al., (1983) presented a study which contains a basis for understanding the phenomenon of scale-dependent dispersion within a deterministic...

182

Pressure viscosity coefficient of vegetable oils  

Technology Transfer Automated Retrieval System (TEKTRAN)

The elastohydrodynamic (EHD) pressure viscosity coefficient (PVC) of ten vegetable oils from commodity and new crops, and two petroleum-based oils, polyalphaolefin (PAO) and hexadecane, were investigated. PVC was measured using three different methods: the So and Klaus (S-K) procedure from oil visco...

183

Computer programs for the concordance correlation coefficient.  

PubMed

The CCC macro is presented for computation of the concordance correlation coefficient (CCC), a common measure of reproducibility. The macro has been produced in both SAS and R, and a detailed presentation of the macro input and output for the SAS program is included. The macro provides estimation of three versions of the CCC, as presented by Lin [L.I.-K. Lin, A concordance correlation coefficient to evaluate reproducibility, Biometrics 45 (1989) 255-268], Barnhart et al. [H.X. Barnhart, J.L. Haber, J.L. Song, Overall concordance correlation coefficient for evaluating agreement among multiple observers, Biometrics 58 (2002) 1020-1027], and Williamson et al. [J.M. Williamson, S.B. Crawford, H.M. Lin, Resampling dependent concordance correlation coefficients, J. Biopharm. Stat. 17 (2007) 685-696]. It also provides bootstrap confidence intervals for the CCC, as well as for the difference in CCCs for both independent and dependent samples. The macro is designed for balanced data only. Detailed explanation of the involved computations and macro variable definitions are provided in the text. Two biomedical examples are included to illustrate that the macro can be easily implemented. PMID:17709153

Crawford, Sara B; Kosinski, Andrzej S; Lin, Hung-Mo; Williamson, John M; Barnhart, Huiman X

2007-08-20

184

Zernike coefficients of a scaled pupil.  

PubMed

By expressing a scaled Zernike radial polynomial as a linear combination of the unscaled radial polynomials, we give a simple derivation for determining the Zernike coefficients of an aberration function of a scaled pupil in terms of their values for a corresponding unscaled pupil. PMID:20885474

Mahajan, Virendra N

2010-10-01

185

ESTIMATING SOURCE COEFFICIENTS FOR PHOSPHORUS SITE INDICES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phosphorus (P) release to runoff varies widely for different land-applied organic-P sources even when applied at equivalent total P rates. To address this variability, some P site indices include tabulated P source coefficients (PSCs) for differential weighting of applied P materials based on their ...

186

ESTIMATING CROP COEFFICIENTS WITH CROP CANOPY SIZE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Planting time, plant density, variety, and cultural practices vary widely for horticultural crops. It is difficult to estimate a basal crop coefficient that can incorporate these variations. Canopy cover, as an indicator of intercepted sunlight, is related to crop water use. We used a weighing ly...

187

Particle drag coefficients in turbulent fluids  

Microsoft Academic Search

An accurate estimation of particle settling velocities, and\\/or of particle drag coefficients, is required for modelling purposes in many industrially important multiphase processes involving the suspension of millimetre and sub-millimetre size particles in a liquid phase. It is known that the settling velocity of particles in a turbulent fluid may be significantly different from that in the still fluid, depending

A. Brucato; F. Grisafi; G. Montante

1998-01-01

188

Generalized Variable-Coefficient KP Equation  

Microsoft Academic Search

The variable-coefficient generalizations of thecelebrated KP equation (GvcKPs) are realistic models forvarious physical and engineering situations. In thisnote, the application of symbolic computation and the truncated Painleve expansion leads toan auto-Backlund transformation and soliton-typedsolutions to a type of the GvcKPs.

Yi-Tian Gao; Bo Tian

1998-01-01

189

Optimal regular differential operators with VMO coefficients  

NASA Astrophysics Data System (ADS)

This paper presents the study of maximal regularity properties for elliptic differential-operator equations with VMO coefficients. We prove that the corresponding elliptic operator is separable, positive and is a generator of an analytic semigroup in vector-valued Lp spaces.

Shakhmurov, Veli

2012-12-01

190

Phosphorus Availability Coefficients from Various Organic Sources  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objectives of this study were to determine Phosphorus Availability Coefficients (PACs) for a variety of organic phosphorus (P) sources, and to examine the relationship between PACs measured in simulated rainfall runoff and alternative soil incubations. PAC is an important parameter in the P-Ind...

191

Diffusion Coefficients in Gravel Under Unsaturated Conditions  

Microsoft Academic Search

Diffusion coefficients were experimentally determined in unsaturated gravel to evaluate the effectiveness of gravel as a diffusion barrier to ionic transport in the vadose zone. Water contents were fixed by use of an ultracentrifuge with an ultralow constant rate flow pump supplying solution to the sample via a rotating seal. Once the gravel was at hydraulic steady state, the electrical

James L. Conca; Judith Wright

1990-01-01

192

The third virial coefficient of free anyons  

NASA Astrophysics Data System (ADS)

We use a path integral representation for the partition function of non-interacting anyons confined in a harmonic oscillator potential in order to prove that the third virial coefficient of free anyons is finite, and to calculate it numerically. Our results together with previously known results are consistent with a rapidly converging Fourier series in the statistics angle.

Myrheim, Jan; Olaussen, Kåre

1993-01-01

193

Symmetries and Interaction Coefficients of Kelvin Waves  

NASA Astrophysics Data System (ADS)

We considered symmetry restriction on the interaction coefficients of Kelvin waves and demonstrated that linear in small wave vector asymptotic, obtained analytically, is not forbidden, as one can expect by naive reasoning. Therefore now we have no reason to doubt in this asymptote, that results in the L’vov-Nazarenko energy spectrum of Kelvin waves.

Lebedev, Vladimir V.; L'Vov, Victor S.

2010-12-01

194

Molecular Diffusion Coefficients: Experimental Determination and Demonstration.  

ERIC Educational Resources Information Center

|Presented are laboratory methods which allow the demonstration and determination of the diffusion coefficients of compounds ranging in size from water to small proteins. Included are the procedures involving the use of a spectrometer, UV cell, triterated agar, and oxygen diffusion. Results including quantification are described. (CW)|

Fate, Gwendolyn; Lynn, David G.

1990-01-01

195

Theoretical basis for an anomalous temperature coefficient in swelling pressure of rabbit corneal stroma.  

PubMed Central

In the rabbit corneal stroma, the swelling pressure, P, has been reported to have an anomalous (negative) temperature coefficient, alpha P, contradicting traditional Donnan swelling theory. A parallel-plate, diffuse double layer Gouy-Chapman model was used to resolve this discrepancy. The present model incorporates the possibility that surface charge, sigma, is temperature dependent. It is shown that negative, zero, or positive coefficients of swelling pressure change with temperature are not mutually exclusive conditions, but can be attributed to the same underlying mechanism. For likely values of alpha P(range -7 x 10(-3) K-1 to +3.2 x 10(-3)K-1), the effective stromal charge has a negative temperature dependency, or dln sigma/dT less than 0. The present formalism is robust against variation in assumed alpha P, and is able to simultaneously satisfy the known values of swelling pressure, its thermal dependency, and stromal charge. These results implicate significant coulombic forces behind P. Predicted stromal surface charge is approximately 0.01 Cm-2. The predictions were confirmed with macrocontinuum Donnan swelling theory, suggesting that Donnan osmotic swelling is the principal macroscopic component of P.

Kwok, L S; Klyce, S D

1990-01-01

196

Alpha-mannosidosis  

PubMed Central

Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are immune deficiency (manifested by recurrent infections, especially in the first decade of life), skeletal abnormalities (mild-to-moderate dysostosis multiplex, scoliosis and deformation of the sternum), hearing impairment (moderate-to-severe sensorineural hearing loss), gradual impairment of mental functions and speech, and often, periods of psychosis. Associated motor function disturbances include muscular weakness, joint abnormalities and ataxia. The facial trait include large head with prominent forehead, rounded eyebrows, flattened nasal bridge, macroglossia, widely spaced teeth, and prognathism. Slight strabismus is common. The clinical variability is significant, representing a continuum in severity. The disorder is caused by lysosomal alpha-mannosidase deficiency. Alpha-mannosidosis is inherited in an autosomal recessive fashion and is caused by mutations in the MAN2B1 gene located on chromosome 19 (19 p13.2-q12). Diagnosis is made by measuring acid alpha-mannosidase activity in leukocytes or other nucleated cells and can be confirmed by genetic testing. Elevated urinary secretion of mannose-rich oligosaccharides is suggestive, but not diagnostic. Differential diagnoses are mainly the other lysosomal storage diseases like the mucopolysaccharidoses. Genetic counseling should be given to explain the nature of the disease and to detect carriers. Antenatal diagnosis is possible, based on both biochemical and genetic methods. The management should be pro-active, preventing complications and treating manifestations. Infections must be treated frequently. Otolaryngological treatment of fluid in the middle ear is often required and use of hearing aids is invariably required. Early educational intervention for development of social skills is needed and physiotherapy is important to improve bodily function. Orthopedic surgery may be necessary. The long-term prognosis is poor. There is an insidiously slow progression of neuromuscular and skeletal deterioration over several decades, making most patients wheel-chair dependent. No patients manage to be completely socially independent. Many patients are over 50 years of age.

Malm, Dag; Nilssen, ?ivind

2008-01-01

197

Finite Range Effects in (alpha, 2alpha) Reactions  

SciTech Connect

Finite range calculations for the (alpha, 2alpha) reactions are performed for the first time to remove huge inconsistencies obtained earlier in conventional zero range analyses. Vagaries of the energy dependent experimental observations up to 200 MeV are understood using the well-established nuclear radii and distorting optical potentials. The results are found to be sensitive to the short distance behavior of the alpha-alpha interaction, indicating the utility of the knockout reactions as a probe of the knockout vertex at short distances. Our approach paves the way to include finite range effects in atomic and molecular physics as also in neutron multiplication calculations.

Jain, Arun K.; Joshi, Bhushan N. [Nuclear Physics Division, Bhabha Atomic Research Center, Mumbai-400 085 (India)

2009-09-25

198

From water clustering to osmotic coefficients.  

PubMed

Water activity is an important macroscopic property of aerosol particles and droplets in the atmosphere as well as aqueous solutions in many other fields of physical chemistry. This study focuses on relating water activity, described using osmotic coefficients, to the microscopic water structure in systems of atmospheric relevance, namely, aqueous solutions of each of the four electrolytes: NaCl, (NH(4))(2)SO(4), NH(4)Cl, and Na(2)SO(4). The osmotic coefficients of these compounds, as reported in literature based on thermodynamic measurements, decrease as a function of molality for dilute solutions and increase as a function of molality for concentrated solutions. At an intermediate molality, a minimum value of the osmotic coefficient is observed. We explain this behavior by describing osmotic coefficients as the product of two concentration-dependent effects: incomplete electrolyte dissociation and variations in the microphysical water structure. The degree of dissociation in electrolyte solutions can be obtained directly from literature or derived from reported pK values, and in this work the water structure is quantified using low-wavenumber Raman spectroscopy. We use the band at 180 cm(-1) in Raman spectra of aqueous electrolyte solutions, which has been assigned to the displacement of the central oxygen atom in a tetrahedral hydrogen bonding environment composed of five H(2)O units. The abundance of such translationally restricted water molecules is essential in describing the local microphysical structure of water, and the height of the band is used to estimate the amount of such translationally restricted water molecules in solution. We were able to qualitatively reproduce and explain literature values of osmotic coefficients for the four studied electrolytes. Our results indicate that the effect of electrolyte dissociation, which decreases as a function of molality, dominates in dilute solutions, whereas changes in water structure are more significant at higher concentrations. PMID:20945872

Frosch, Mia; Bilde, Merete; Nielsen, Ole F

2010-11-11

199

Layer coefficients for NHDOT pavement materials  

NASA Astrophysics Data System (ADS)

In 1992, the New Hampshire Department of Transportation (NHDOT) experimented with the use of reclaimed asphalt concrete as a base course material, identified by NHDOT as reclaimed stabilized base (RSB). The RSB and a control test section were placed on Interstate 93 between exits 18 and 19. The RSB test section was designed to the same structural number (SN) as the control. To evaluate the structural capacity of these test sections, the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) conducted deflection tests using a Dynatest 8000 falling weight deflectometer (FWD). Preliminary analysis of the results by NHDOT personnel showed higher deflection in the reclaimed asphalt concrete test sections. The explanation was that the layer coefficient used for the RSB layer in the design was probably incorrect. A total of 10 test sections constituting the base course materials used by NHDOT were built near Bow, New Hampshire. CRREL evaluated and estimated the layer coefficients of the base course materials. The test program was developed to characterize the material in more than one way. Tests were conducted with the heavy weight deflectometer (HWD), dynamic cone penetrometer (DCP) and the Clegg hammer. In situ California bearing ratio (CBR) tests were also conducted. The deflection from the HWD were used with the WESDEF back calculation program to determine the layer moduli. The moduli were than used with the AASHTO Design Guide to calculate the layer coefficients. The layer coefficients were also determined with the method proposed by Rohde. The CBR values from the Clegg hammer, in situ CBR and DCP tests were also used in the relationships in the HDM model to determine the layer coefficients.

Janoo, Vincent C.

1994-09-01

200

Drosophila melanogaster importin alpha1 and alpha3 can replace importin alpha2 during spermatogenesis but not oogenesis.  

PubMed Central

Importin alpha's mediate the nuclear transport of many classical nuclear localization signal (cNLS)-containing proteins. Multicellular animals contain multiple importin alpha genes, most of which fall into three conventional phylogenetic clades, here designated alpha1, alpha2, and alpha3. Using degenerate PCR we cloned Drosophila melanogaster importin alpha1, alpha2, and alpha3 genes, demonstrating that the complete conventional importin alpha gene family arose prior to the split between invertebrates and vertebrates. We have begun to analyze the genetic interactions among conventional importin alpha genes by studying their capacity to rescue the male and female sterility of importin alpha2 null flies. The sterility of alpha2 null males was rescued to similar extents by importin alpha1, alpha2, and alpha3 transgenes, suggesting that all three conventional importin alpha's are capable of performing the important role of importin alpha2 during spermatogenesis. In contrast, sterility of alpha2 null females was rescued only by importin alpha2 transgenes, suggesting that it plays a paralog-specific role in oogenesis. Female infertility was also rescued by a mutant importin alpha2 transgene lacking a site that is normally phosphorylated in ovaries. These rescue experiments suggest that male and female gametogenesis have distinct requirements for importin alpha2.

Mason, D Adam; Fleming, Robert J; Goldfarb, David S

2002-01-01

201

Gross alpha analytical modifications that improve wastewater treatment compliance  

SciTech Connect

This paper will propose an improvement to the gross alpha measurement that will provide more accurate gross alpha determinations and thus allow for more efficient and cost-effective treatment of site wastewaters. To evaluate the influence of salts that may be present in wastewater samples from a potentially broad range of environmental conditions, two types of efficiency curves were developed, each using a thorium-230 (Th-230) standard spike. Two different aqueous salt solutions were evaluated, one using sodium chloride, and one using salts from tap water drawn from the Bergen County, New Jersey Publicly Owned Treatment Works (POTW). For each curve, 13 to 17 solutions were prepared, each with the same concentration of Th-230 spike, but differing in the total amount of salt in the range of 0 to 100 mg. The attenuation coefficients were evaluated for the two salt types by plotting the natural log of the counted efficiencies vs. the weight of the sample's dried residue retained on the planchet. The results show that the range of the slopes for each of the attenuation curves varied by approximately a factor of 2.5. In order to better ensure the accuracy of results, and thus verify compliance with the gross alpha wastewater effluent criterion, projects depending on gross alpha measurements of environmental waters and wastewaters should employ gross alpha efficiency curves prepared with salts that mimic, as closely as possible, the salt content of the aqueous environmental matrix. (authors)

Tucker, B.J. [Shaw Environmental and Infrastructure, Salem, NH (United States); Arndt, S. [Safety and Ecology Corporation, Maywood, NJ (United States)

2007-07-01

202

Alpha-particle microdosimetry.  

PubMed

With the increasing availability of alpha emitters, targeted ?-particle therapy has emerged as a solution of choice to treat haematological cancers and micrometastatic and minimal residual diseases. Alpha-particles are highly cytotoxic because of their high linear energy transfer (LET) and have a short range of a few cell diameters in tissue, assuring good treatment specificity. These radiologic features make conventional dosimetry less relevant for that context. Stochastic variations in the energy deposited in cell nuclei are important because of the microscopic target size, low number of ?- particle traversals, and variation in LET along the ?-particle track. Microdosimetry provides a conceptual framework that aims at a systematic analysis of the stochastic distribution of energy deposits in irradiated matter. The different quantities of microdosimetry and the different methods of microdosimetric calculations were described in the early eighties. Since then, numerous models have been published through the years and applied to analyse experimental data or to model realistic therapeutic situations. Major results have been an accurate description of the high toxicity of ?-particles, and the description of the predominant effect of activity distribution at the cellular scale on toxicity or efficacy of potential targeted ?-particle therapies. This last factor represents a major limitation to the use of microdosimetry in vivo because determination of the source - target distribution is complicated. The future contributions of microdosimetry in targeted ?-particle therapy research will certainly depend on the ability to develop high-resolution detectors and on the implementation of pharmaco-kinetic models at the tumour microenvironment scale. PMID:22201713

Chouin, Nicolas; Bardies, Manuel

2011-07-01

203

Systematics of Alpha-Radioactivity  

Microsoft Academic Search

Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region

I. Perlman; A. Ghiorso; G. T. Seaborg

1949-01-01

204

Systematics of Alpha-Radioactivity  

Microsoft Academic Search

Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region

I. Perlman; A. Ghiorso; G. T. Seaborg

1950-01-01

205

Prothymosin alpha in Human Blood  

Microsoft Academic Search

The major cross-reacting peptide in human plasma detected with a radioimmunoassay (RIA) for thymosin alpha 1 was identified as prothymosin alpha , based on its elution properties in gel-filtration chromatography and its amino acid composition after purification by HPLC. A small quantity (<10%) of the total cross-reacting material was recovered in fractions corresponding to lower molecular weight thymosin alpha 1-like

C. Panneerselvam; A. A. Haritos; J. Caldarella; B. L. Horecker

1987-01-01

206

A Statistical Analysis of YORP Coefficients  

NASA Astrophysics Data System (ADS)

The YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect is theorized to be a major factor in the evolution of small asteroids (<10 km) in the near-Earth and main belt populations. YORP torques, which originate from absorbed sunlight and subsequent thermal radiation, causes secular changes in an asteroid's spin rate and spin vector orientation (e.g. Rubincam, Journal of Geophysical Research, 1995). This in turn controls the magnitude and direction of the Yarkovsky effect, which causes a drift in an asteroid's heliocentric semi-major axis (Vokrouhlicky and Farinella, Nature, 2000). YORP is also thought to be responsible for the creation of multiple asteroid systems and asteroid pairs through the process of rotational fission (Pravec et al, Nature, 2010). Despite the fact that the YORP effect has been measured on several asteroids (e.g. Taylor et al, Science, 2007 and Kaasalainen et al, Nature, 2007), it has proven very difficult to predict the effect accurately from a shape model due to the sensitivity of the YORP coefficients to shape changes (Statler, Icarus, 2009). This has been especially troublesome for Itokawa, for which a very detailed shape model is available (Scheeres et al, Icarus 2007; Breiter et al, Astronomy & Astrophysics, 2009). In this study, we compute the YORP coefficients for a number asteroids with detailed shape models available on the PDS-SBN. We then statistically perturb the asteroid shapes at the same resolution, creating a family of YORP coefficients for each shape. Next, we analyze the change in YORP coefficients between a shape model of accuracy obtainable from radar with one including small-scale topography on the surface as was observed on Itokawa. The combination of these families of coefficients will effectively give error bars on our knowledge of the YORP coefficients given a shape model of some accuracy. Finally, we discuss the statistical effect of boulder and craters, and the modification of these results due to recent studies on thermal beaming (Rozitis and Green, Mon. Not. R. Astron. Soc., 2012) and "tangential" YORP (Golubov and Krugly, The Astrophysical Journal Letters, 2012).

McMahon, Jay W.; Scheeres, D.

2013-10-01

207

Alpha particle confinement in tokamaks  

SciTech Connect

An assessment of diffusive tokamak transport mechanisms of concern for alpha particles indicates that the ''stochastic regime'' is the only one which appears to pose a real danger for adequate alpha confinement. This fact, in conjunction with the threshold character of that mechanism, allows one to decide whether an alpha born at a given location will be lost or confined, according to a very simple criterion. Implementing this criterion numerically results in a new code for the assessment of alpha confinement, which is orders of magnitude faster than earlier codes used for this purpose. 13 refs., 3 figs., 1 tab.

White, R.B.; Mynick, H.E.

1988-11-01

208

Satellite ballistic coefficients and the lower thermosphere  

NASA Astrophysics Data System (ADS)

Observed variations in the estimated ballistic coefficients (B') for satellites in the lower thermosphere during 2001, have been used to study its implications for atmospheric densities with respect to changes in the solar and geomagnetic activities. It is shown that the steady state density models predict the true densities within 10% as a function of solar activity, except during strong geomagnetic storms, when true densities are underestimated by about 15%. The variations in B' with days point to a semiannual variation (SAV) in the scaling factor required to correctly predict SAV in the true densities from steady state models. The calculations also show that changes in density ratios during some major geomagnetic storms can not be explained by steady state models. The Ncar-Tigcm models may be used to see if these bring B' closer to true ballistic coefficients than the steady state models.

Bhatnagar, V. P.; Germany, G. A.; Tan, A.

2005-02-01

209

Drag coefficient of an electrophoretic colloidal particle  

NASA Astrophysics Data System (ADS)

Electrophoretic mobility is a measure to determine the electric charges on a colloidal particle. Zeta potential, a concept originated by Smoluchowski, has been a standard for quantifying the surface charge density for the electric double-layers that are thin compared to the particle radius. Various models have been suggested to improve Smoluchowski's theory for systems with Debye length not thin compared to the particle radius. Central to the issue is that the fluid flow due to the external field-induced counter-ion motion is unknown. Using optical tweezers to trap a colloidal particle in a low-frequency electric field, we found the drag coefficient of the particle in the field to be non-Stokes. We discuss how the non-Stokes' drag coefficient as a function of salt concentration and particle size may be useful for interpreting different models of Zeta potential.

Reddy, Kathryn; Wei, Ming-Tzo; Cohen, Joel A.; Ou-Yang, H. Daniel

2013-03-01

210

Minior Actinide Doppler Coefficient Measurement Assessment  

SciTech Connect

The "Minor Actinide Doppler Coefficient Measurement Assessment" was a Department of Energy (DOE) U-NERI funded project intended to assess the viability of using either the FLATTOP or the COMET critical assembly to measure high temperature Doppler coefficients. The goal of the project was to calculate using the MCNP5 code the gram amounts of Np-237, Pu-238, Pu-239, Pu-241, AM-241, AM-242m, Am-243, and CM-244 needed to produce a 1E-5 in reactivity for a change in operating temperature 800C to 1000C. After determining the viability of using the assemblies and calculating the amounts of each actinide an experiment will be designed to verify the calculated results. The calculations and any doncuted experiments are designed to support the Advanced Fuel Cycle Initiative in conducting safety analysis of advanced fast reactor or acceoerator-driven transmutation systems with fuel containing high minor actinide content.

Nolan E. Hertel; Dwayne Blaylock

2008-04-10

211

Manning's roughness coefficient for Illinois streams  

USGS Publications Warehouse

Manning's roughness coefficients for 43 natural and constructed streams in Illinois are reported and displayed on a U.S. Geological Survey Web site. At a majority of the sites, discharge and stage were measured, and corresponding Manning's coefficients—the n-values—were determined at more than one river discharge. The n-values discussed in this report are computed from data representing the stream reach studied and, therefore, are reachwise values. Presentation of the resulting n-values takes a visual-comparison approach similar to the previously published Barnes report (1967), in which photographs of channel conditions, description of the site, and the resulting n-values are organized for each site. The Web site where the data can be accessed and are displayed is at URL http://il.water.usgs.gov/proj/nvalues/.

Soong, David T.; Prater, Crystal D.; Halfar, Teresa M.; Wobig, Loren A.

2012-01-01

212

Seeley-Gilkey Coefficients for Superoperators  

NASA Astrophysics Data System (ADS)

Starting from a expansion of exp[-(A0 + A1)t] in powers of A1, we can obtain Seeley-Gilkey coefficients an(x,y) for when H has dependency on both bosonic and fermionic variables. We consider operators of the form H = p2 + ?L·p + p · ?R + ?(p? - i?) where, in general, ?L ? ?R. To illustrate how these can be used, we compute in closed form the coefficient a1(x,x) and from it the ?-function in a three-dimensional model in which a spinor couples to an Abelian vector field with a topological action. The ?-function turns out not to have the form of the classical action.

McKeon, D. G. C.

213

Materials with Tailored Thermal Expansion Coefficient  

NASA Astrophysics Data System (ADS)

Designing materials with tailored coefficient of thermal expansion (CTE) has applications in a number of fields, including biomedical and mechanical engineering and solar energy. It is particularly important to combine a desired (usually low) CTE with mechanical robustness. Most of previous work has been focused on designing low-CTE materials by modifying compounds at the chemical level. It is also possible to design materials with tailored CTE by using specific topologies of different materials to achieve overall properties outside the range of the constituent materials. Here, we exploit buckling in laminated periodic structures to design materials whose coefficient of thermal expansion can be tuned (from positive to negative) by varying the unit cell geometry.

Bertoldi, Katia; Liu, Jia; Shan, Sicong; Kang, Sung Hoon

2013-03-01

214

Rotational dissipation and the Miesowicz coefficients  

NASA Astrophysics Data System (ADS)

In this work, we will study the relative contribution of each of the two dissipative channels of the Eriksen, Leslie, and Parodi (ELP) approach to the observed values of the Miesowicz viscosity coefficients of the nematic liquid crystals. According to the fundamental equation of the liquid crystal’s viscosity dissipative process, T?=-?d3r{?ijAij+h??N?} , there are two channels by which the nematic viscous dissipation can occur: or it occurs by means of a shear flow configuration, where Aij is the characterizing term, or it occurs by means of a rotational configuration, where N? is the characterizing term (these parameters will be defined in the paper). It will be also shown that this relative contribution can be measured by a simple relationship connecting the Miesowicz coefficients, which exhibits a quasitemperature independent behavior, suggesting that it is nearly constant through the entire domain of the nematic phase.

Simões, M.; Yamaguti, K.; Palangana, A. J.

2009-12-01

215

Soret Coefficient of Some Binary Liquid Mixtures  

NASA Astrophysics Data System (ADS)

We have measured with the thermogravitational method the Soret coefficient of the binary liquid systems: benzene+nhexane, toluene+nheptane and carbon tetrachloride with heptane and hexane, in a well characterized column used in a previous work to measure the systems benzene+nheptane and toluene+nhexane. The obtained results show that the Soret coefficient takes nearly the same value in the mixtures of each one of the components, benzene, toluene or carbon tetrachloride with hexane and heptane. For all the systems considered it varies slowly with the concentration and is nearly independent of temperature. The higher values of the thermal diffusion factor correspond to mixtures containing carbon tetrachloride. Previous results for these systems were obtained in an imperfect apparatus and must be disregarded.

Bou-Ali, M. M.; Ecenarro, O.; Madariaga, J. A.; Santamaría, C. M.; Valencia, J. J.

1999-12-01

216

Finite Temperature Chern-Simons Coefficient  

SciTech Connect

We compute the exact finite temperature effective action in a (0+1)-dimensional field theory containing a topological Chern-Simons term, which has many features in common with (2+1)-dimensional Chern-Simons theories. This exact result explains the origin and meaning of puzzling temperature dependent coefficients found in various naive perturbative computations in the higher dimensional models. {copyright} {ital 1997} {ital The American Physical Society}

Dunne, G. [Physics Department, University of Connecticut, Storrs, Connecticut 06269 (United States); Lee, K.; Lu, C. [Department of Physics, Columbia University, New York, New York 10027 (United States)

1997-05-01

217

Quenching of spontaneous emission coefficients in plasmas  

SciTech Connect

We have observed changing Einstein coefficients of spontaneous emission as a function of electron density in CO/sub 2/ laser-produced plasmas. These measurements are based on the intensity branching ratio of CIV lines 5801 to 5812 A and 312.41 to 312.46 A which share a common upper level. Similar observations for CIII lines are also discussed. 12 refs., 3 figs.

Chung, Y.; Lemaire, P.; Suckewer, S.

1987-09-01

218

Internal conversion coefficients for superheavy elements  

NASA Astrophysics Data System (ADS)

Internal conversion coefficients (ICC) were calculated for all atomic subshells of the elements with 104?Z?126, E1...E4, M1...M4 multipolarities and transition energies between 10 and 1000 keV. The atomic screening was treated in the relativistic Hartree-Fock-Slater model. Tables comprising almost 90 000 subshell and total ICC were deposited at the LANL preprint server (http://xxx.lanl.gov/e-print/nucl-th/0004003).

Dragoun, O.; Rysavý, M.; Dragoun, O.; Spalek, A.

2000-10-01

219

Thermal expansion and kinetic coefficients of crystals  

Microsoft Academic Search

Electrical (?) and thermal (W) resistivities and thermal expansion coefficient (?) of Cu, Zn, Al, Pb, Ni, ?-brass, Al2O3, NaCl, Si, SiO2(?), and SiO2(?) were simultaneously measured with standard four-probe, absolute steady-state, and quartz dilatometer techniques. Measurements of Ni and ?-brass were performed at temperatures from 300 to 1100K and measurements of all other samples were made between 90 and

I. M. Abdulagatov; Zh. Kh. Murlieva; D. K. Palchaev; K. K. Kazbekov; M. M. Maangalov

2007-01-01

220

Thermal expansion and kinetic coefficients of crystals  

Microsoft Academic Search

Electrical (rho) and thermal (W) resistivities and thermal expansion coefficient (beta) of Cu, Zn, Al, Pb, Ni, beta-brass, Al2O3, NaCl, Si, SiO2(||), and SiO2(?) were simultaneously measured with standard four-probe, absolute steady-state, and quartz dilatometer techniques. Measurements of Ni and beta-brass were performed at temperatures from 300 to 1100 K and measurements of all other samples were made between 90

I. M. Abdulagatov; Zh. Kh. Murlieva; D. K. Palchaev; K. K. Kazbekov; M. M. Maangalov

2007-01-01

221

Extraction of the coefficient of giant magnetoresistance  

SciTech Connect

Element specific magnetic hysteresis (ESMH) loops have been used in conjunction with measured magnetoresistance curves to extract the coefficient of giant magnetoresistance (GMR), which is the maximum achievable value of the GMR independent of magnetic domain effects and incomplete moment alignment effects, for sputtered Fe/Cu/Co sandwiches on silicon substrates. Using the ESMH loops to calculate GMR curves, comparison with the measured GMR curves shows that the magnetization reversal process is best described by multidomain Ising behavior.

Idzerda, Y.U. (Naval Research Laboratory, Washington, DC 20375 (United States)); Chen, C. (AT T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974 (United States)); Cheng, S. (Naval Surface Warfare Center, Silver Spring, Maryland 20910 (United States)); Vavra, W.; Prinz, G.A. (Naval Research Laboratory, Washington, DC 20375 (United States)); Meigs, G.; Lin, H. (AT T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974 (United States)); Ho, G.H. (Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States))

1994-06-20

222

Vertical transfer coefficient in natural streams  

Microsoft Academic Search

Turbulent vertical transfer in natural open and under-ice channel flows is considered. Methods for the assessment of turbulent\\u000a viscosity in the core and shift layers of under-ice flow are proposed and checked. A method is developed for the calculation\\u000a of the vertical distribution of turbulent exchange coefficient in an underice flow given the mean flow characteristics.

E. N. Dolgopolova

2008-01-01

223

Shear viscosity coefficient from microscopic models  

Microsoft Academic Search

The transport coefficient of shear viscosity is studied for a hadron matter through microscopic transport model, the ultrarelativistic quantum molecular dynamics (UrQMD), using the Green-Kubo formulas. Molecular-dynamical simulations are performed for a system of light mesons in a box with periodic boundary conditions. Starting from an initial state composed of pi,eta,omega,rho,varphi with a uniform phase-space distribution, the evolution takes place

Azwinndini Muronga

2004-01-01

224

Pearson's Product-Moment Coefficient of Correlation  

NSDL National Science Digital Library

This tutorial, created by Thomas W. MacFarland of Nova Southeastern University, explains the theory and use of Pearson's Product Moment Coefficient of Correlation and demonstrates it with an example on GPA and test scores. Data sets are provided in both SPSS and Minitab code. This is a great resource for anyone looking for a more in-depth study of statistics. This could be used as either a teaching guide for educators or simply further practice for students.

Macfarland, Thomas W.

2009-09-11

225

Spearman's Rank-Difference Coefficient of Correlation  

NSDL National Science Digital Library

This tutorial, created by Thomas W. MacFarland of Nova Southeastern University, explains the theory and use of the Spearman's Rank-Difference Correlation Coefficient and demonstrates it with an example on exam scores, homework scores, and project scores. Data sets are provided in both SPSS and Minitab code. This is a great resource for anyone interested in a more in-depth study of statistics.

Macfarland, Thomas W.

2009-01-21

226

Dependence of the dissociative recombination coefficient of molecular ions Kr_2^+ with electrons on the electron and gas temperatures  

NASA Astrophysics Data System (ADS)

This paper presents the measured values of the dissociative recombination coefficient of molecular Kr_2^+ ions with electrons ? (Kr_2^+) as a function of both electron and gas temperatures. The measurements were made using a dual-mode (waveguide-cavity) microwave X-band apparatus. The recombination coefficient can be expressed as \\alpha _{Kr_2^+} (T_{gas} ,T_e )=1.4\\times 10^{-6}(T_{gas} /300\\,K)^{-0.97}(T_e /300\\,K)^{-0.53}\\,(cm^3\\,s^{-1},K) in the temperature ranges 300 K ? Tgas ? 500 K and 300 K ? Te ? 19?000 K.

Luká?, P.; Mikuš, O.; Morva, I.; Zábudlá, Z.; Trnovec, J.; Morvová, M.; Hensel, K.

2012-12-01

227

Thermal expansion and kinetic coefficients of crystals  

NASA Astrophysics Data System (ADS)

Electrical (?) and thermal (W) resistivities and thermal expansion coefficient (?) of Cu, Zn, Al, Pb, Ni, ?-brass, Al2O3, NaCl, Si, SiO2(?), and SiO2(?) were simultaneously measured with standard four-probe, absolute steady-state, and quartz dilatometer techniques. Measurements of Ni and ?-brass were performed at temperatures from 300 to 1100 K and measurements of all other samples were made between 90 and 500 K. This temperature range includes the range below and above the Debye temperature (TD). The total uncertainties of the specific electrical and thermal resistivities and thermal expansion coefficient (TEC) measurements are 0.5%, 3.0%, and (1.5 4.0%), respectively. The universal linear relationship between the electrical and thermal resistivities and ?? over the wide temperature range was found experimentally. Using the Landau criterion for convection development for ideal phonon and electron gases in the solids, the universal relations, ?/???T and W/W??T (where ?ph is the phonon electrical resistivity, ?=eE˜/Jcp? is the characteristic electrical resistivity, Wph is the phonon thermal resistivity, and W=kG/qcp is the characteristic thermal resistivity) between relative phonon electrical and phonon thermal resistivities and ?? were derived. The derived universal relations provide a new method for estimating the kinetic coefficients (electrical and thermal resistivities) from TEC measurements.

Abdulagatov, I. M.; Murlieva, Zh. Kh.; Palchaev, D. K.; Kazbekov, K. K.; Maangalov, M. M.

2007-09-01

228

Understanding correlation coefficients in treaty verification. Revised  

SciTech Connect

When a pair of images is compared on a point-by-point basis, the linear-correlation coefficient is usually used as a measure of similarity or dissimilarity. This report evaluates the theoretical underpinnings and limitations of the linear-correlation coefficient, as well as other related statistics, particularly for cases where inherent white noise is present. As a result of the limitations in linear-correlation, an additional step has been derived -- local-sum clustering -- in order to improve recognition of small dissimilarities in a pair of otherwise identical images. Results show an optimal three-stage procedure: first, establish congruence of the two images; second, use the linear-correlation coefficient as a test of true negatives; and, third, qualify a true positive by using the cluster (local-sum) method. These three algorithmic stages would be especially useful in application to arms control treaty verification, particularly for comparison of unique identifiers (tags or seals). This is illustrated by comparing scanning-electron microscope topographical images for an intrinsic-surface tag.

DeVolpi, A.

1993-02-01

229

Virial Coefficients Using Different Equations of State  

NASA Astrophysics Data System (ADS)

Inexpensive desktop computers and powerful computer algebra software packages have made it possible for students and faculty to look at problems unthinkable a few years past because of the intensive algebra involved. One such problem is the derivation of expressions for the first three virial coefficients when using different equations of state. Using Mathematica, expressions for the virial coefficients at constant volume, constant pressure, and the fugacity have been derived for several equations of state. The results of these calculations are shown in two plots with experimental data. These plots serve as a check on the validity of the expressions derived using Mathematica. Our purpose is to illustrate the actual Mathematica instructions that lead to the virial coefficients for the well-known van der Waals equation of state. The set of Mathematica instructions for this equation of state will serve as a model for other more sophisticated equations of state. In our study we selected the Redlich-Kwong and the Gibbons, Laughton modification to the Redlich-Kwon equations of state.

Wakefield, Charles B.; Phillips, Constance

2000-10-01

230

Alpha Magnetic Spectrometer  

NASA Astrophysics Data System (ADS)

The Alpha Magnetic Spectrometer (AMS) is a precision particle physics magnetic spectrometer designed to measure electrons, positrons, gamma rays and various nuclei and anti-nuclei from the cosmos up to TeV energy ranges. AMS weighs 7.5 tons and measures 5 meters by 4 meters by 3 meters. It contains 300,000 channels of electronics and 650 onboard microprocessors. It was delivered to the International Space Station onboard space shuttle Endeavour and installed on May 19, 2011. Since that time, more than 14 billion cosmic ray events have been collected. All the detectors function properly. At this moment, we are actively engaged in data analysis. AMS is an international collaboration involving 16 countries and 60 institutes. It took 16 years to construct and test. AMS is the only major physical science experiment on the International Space Station and will continue to collect data over the entire lifetime of the Space Station (10-20 years).

Ting, Samuel

2012-07-01

231

Alpha olefin oligomerization catalyst  

SciTech Connect

This patent describes a catalyst active for oligomerizing one or more oligomerizable alpha olefin monomers in a hydrocarbon solvent to produce linear olefin oligomers of from about 4 to about 20 carbon atoms. It comprises an organometallic compound wherein the metal thereof is selected from the group consisting of zinc, magnesium, and aluminum, in combination with the reaction mixture obtained by reacting in a hydrocarbon, a zirconium compound of the formula ZrX{sub n}Y{sub 4{minus}n} wherein X is a halogen, Y is selected from the group consisting of aryloxides, alkoxides, and carboxylates, and n ranges from 1 to 4, inclusive, and a basic salt of a carboxylic acid.

Fries, R.W.

1992-05-26

232

Water permeability of plant cuticles: permeance, diffusion and partition coefficients  

Microsoft Academic Search

Using isolated cuticular membranes from ten woody and herbaceous plant species, permeance and diffusion coefficients for water were measured, and partition coefficients were calculated. The cuticular membranes of fruit had much higher permeance and diffusion coefficients than leaf cuticular membranes from either trees or herbs. Both diffusion and partition coefficients increased with increasing membrane thickness. Thin cuticles, therefore, tend to

Matthias Becker; Gerhard Kerstiens; Jörg Schönherr

1986-01-01

233

On estimation and hypothesis testing problems for correlation coefficients  

Microsoft Academic Search

A selection of statistical problems commonly encountered in psychological or psychiatric research concerning correlation coefficients are re-evaluated in the light of recently developed simplifications in the forms of the distribution theory of the intraclass correlation coefficient (exact theory), of the product-moment correlation coefficient and of the Spearman rank correlation coefficient (approximate).

Helena Chmura Kraemer

1975-01-01

234

Velocity slip and temperature jump coefficients for gaseous mixtures. IV. Temperature jump coefficient  

Microsoft Academic Search

The temperature jump coefficient was calculated for a binary gaseous mixture on the basis of the McCormack kinetic model of the Boltzmann equation, which was solved by the discrete velocity method. The calculations were carried out for the three mixtures of noble gases: neon–argon, helium–argon and helium–xenon. A strong influence of the intermolecular interaction on the temperature jump coefficient was

Felix Sharipov; Denize Kalempa

2005-01-01

235

Near-millimeter refractive indices, absorption coefficients, and electrooptic coefficients in ferroelectric and other crystals  

Microsoft Academic Search

We have used a Michelson interferometer operating in the power mode to measure the refractive indices and absorption coefficients over the near-millimeter-wave (NMMW) spectral region of single-crystal bismuth germanium oxide, bismuth silicon oxide, titanium dioxide, lithium niobate, lithium tantalate, and strontium titanate. The NMMW value of the electrooptic coefficient r33 for dc fields in lithium niobate was also measured.

P. S. Brody; J. P. Sattler; G. J. Simonis

1983-01-01

236

Lyman Alpha Tomography  

NASA Astrophysics Data System (ADS)

Narrow-band filters are often used to find emission-line galaxies at predetermined redshifts. When applied to high-redshift Lyman Alpha Emitting galaxies, typical surveys include galaxies over a redshift range of delta_z=0.1. We show that narrow-band filters with overlapping bandpasses can be used to pinpoint the redshifts of emission-line galaxies to much higher precision, by performing tomography using the ratio of fluxes between the two filters to identify the precise wavelength where the emission line falls. We report an empirical test of this technique, using deep NB4990 and NB5015 Angstrom MUSYC images of the Extended Chandra Deep Field-South obtained at the CTIO 4m telescope (Gawiser et al. 2006, Ciardullo et al. 2011.) While formally a type of photometric redshift, Lyman Alpha Tomography allows the redshifts of these galaxies to be determined to delta_z/(1+z)=0.002, which is the same precision achievable with low-resolution (R=100) spectrographs for these dim, single-emission-line galaxies. Determining the redshifts reveals emission-line luminosities and, when combined with broadband imaging, equivalent widths (EW). Hence this technique enables large galaxy redshift surveys that simultaneously reveal emission-line galaxy luminosity functions and EW distributions without the need to perform resource-intensive spectroscopy. We discuss how the technique can be employed on next generation wide-field imagers, including DECam, Hyper Suprime Cam, and ODI. This material is based upon work supported by the National Science Foundation under Grant Nos. 0807570, 0807885, 1055919, and by DOE grants DE-GF02-08ER41560 and DE-FG02-08ER41561.

Gawiser, Eric J.; Kanarek, G.; Ciardullo, R.; Gronwall, C.; MUSYC Collaboration

2012-05-01

237

Supplementation of Alpha 1-Antitrypsin.  

National Technical Information Service (NTIS)

The aim of the study is to explore the feasibility of preparing alpha 1-antitrypsin from the plasma of carefully screened donors who have been found to be free of testable liver abnormalities and eventually supplement patients having inherited alpha 1-ant...

B. H. Bowman G. Powell D. R. Barnett J. C. Gan

1975-01-01

238

Tests of Hypotheses Arising In the Correlated Random Coefficient Model*  

PubMed Central

This paper examines the correlated random coefficient model. It extends the analysis of Swamy (1971), who pioneered the uncorrelated random coefficient model in economics. We develop the properties of the correlated random coefficient model and derive a new representation of the variance of the instrumental variable estimator for that model. We develop tests of the validity of the correlated random coefficient model against the null hypothesis of the uncorrelated random coefficient model.

Heckman, James J.; Schmierer, Daniel

2010-01-01

239

Nano \\/spl alpha\\/Fe\\/epoxy resin composite absorber coatings fabricated by thermal spraying technique  

Microsoft Academic Search

In this paper, the low temperature high velocity air fuel (LTHVAF) spraying technique was applied to prepare the alpha-Fe\\/epoxy resin nanocomposite coatings. The composite powders were mixed with different mass fractions, and the microstructure and reflectivity coefficient of coatings were tested. The results show that the microstructure of coatings is dense and low porosity; nano metal particles are dispersed in

Xiaojing Yuan; Hangong Wang; Genliang Hou; Li Jiang; Chunjiang Yao

2006-01-01

240

Alpha-trifluoromethylated carbanion synthons.  

PubMed

Trifluomethylated organic compounds often have properties that make them suitable for diverse applications, including materials science, agrochemistry, and pharmaceutical industry. But of all the therapeutic drugs currently available, about 10% of them have a partially fluorinated moiety. Thus, a great deal of attention is being paid to the development of reliable methodologies for trifluoromethylation. Introduction of a trifluoromethyl group into the target molecules mostly relies on either trifluoromethylating reagents or trifluoromethylated synthetic blocks. The chemistry of trifluoromethyl carbanions, nucleophilic trifluoromethylating agents such as the Ruppert-Prakash reagent, and organometallic species has been intensively developed for their important synthetic applications. But the chemistry of beta,beta,beta-trifluoroethyl carbanions (alpha-trifluoromethyl carbanions) and organometallic species has remained undeveloped despite their potential usefulness in organic synthesis. The issue needs to be addressed. This Account outlines successful alkylations and useful synthetic applications of alpha-trifluoromethyl carbanions, such as alpha-substituted beta,beta,beta-trifluoroethyl, alpha-trifluoromethylethenyl, trifluoroacetimidoyl, alpha-trifluoromethyloxiranyl, and related alpha-trifluoromethylated carbanions. The strong electron-withdrawing effect of the alpha-trifluoromethyl group may stabilize the carbanion species electronically. But alpha-trifluoromethyl carbanions and their corresponding organometallic species mostly release fluoride spontaneously to produce difluoroalkenes. This notorious decomposition of alpha-trifluoromethylated carbanions and anionoids has hindered the development of these species for organic synthesis. A well-designed device for the generation, stabilization, and acceleration for alkylation of the alpha-trifluoromethylated carbanions is needed for their synthetic application, as well as stabilization by the electron-withdrawing alpha-substituent. The reported alpha-substituted alpha-trifluoromethyl carbanions can be roughly categorized into three classes based on their structures. The first category, A, is pi-conjugation-stabilized carbanions, which are stabilized by ester, nitro, sulfone, carbonyl, or phenyl groups. alpha-Substituents of these carbanions can delocalize the negative charges on their pi-system with large sigma R electron-withdrawing effects; this prevents accumulation of negative charge on the fluorine atoms. The second category, B, consists of carbanions with sp(3) orbitals either of highly halogenated carbanionsexamples include pentafluoroethyl(trimethyl)fluorosilicate, pentafluoroethyllithium, and alpha,alpha-dichloro-beta,beta,beta-trifluoroethylzinc speciesor of cyclic structures such as oxiranyl- and aziridinyllithiums. Both of these carbanions are also stabilized since they reduce molecular orbital (MO) overlapping of the carbanion orbital to C-F bond orbitals. The third category, C, has carbanions with their anion center at the sp(2) orbital, such as alpha-trifluoromethylated alkenyl carbanions and imidoyl carbanions. These sp(2) orbitals of the carbanion center usually have a small overlap with the C-F bonds of trifluoromethyl groups. The small overlap is able to suppress the E2-type eliminations. alpha-Trifluoromethylated carbanions are, in general, unstable. Their stability is largely affected by factors like hybridization of the orbital that accommodates lone pair electrons, the electronic nature of the alpha-substituents, the degree of covalency in a bond between the carbon and metal, the class of countercation, stabilization by chelation of a metal cation, and so on. The stability, therefore, can be sometimes controlled by tuning these factors adequately so that they can be used for organic synthesis. The chemistry of alpha-trifluoromethylated carbanions for organic synthesis has been progressing steadily. However, the simplest trifluoroethyl and trifluoroacetyl carbanions have never been successfully produced and employed for organic synthesis. Elegant gene

Uneyama, Kenji; Katagiri, Toshimasa; Amii, Hideki

2008-06-14

241

The vascular smooth muscle alpha-actin gene is reactivated during cardiac hypertrophy provoked by load.  

PubMed

Cardiac hypertrophy triggered by mechanical load possesses features in common with growth factor signal transduction. A hemodynamic load provokes rapid expression of the growth factor-inducible nuclear oncogene, c-fos, and certain peptide growth factors specifically stimulate the "fetal" cardiac genes associated with hypertrophy, even in the absence of load. These include the gene encoding vascular smooth muscle alpha-actin, the earliest alpha-actin expressed during cardiac myogenesis; however, it is not known whether reactivation of the smooth muscle alpha-actin gene occurs in ventricular hypertrophy. We therefore investigated myocardial expression of the smooth muscle alpha-actin gene after hemodynamic overload. Smooth muscle alpha-actin mRNA was discernible 24 h after coarctation and was persistently expressed for up to 30 d. In hypertrophied hearts, the prevalence of smooth muscle alpha-actin gene induction was 0.909, versus 0.545 for skeletal muscle alpha-actin (P less than 0.05). Ventricular mass after 2 d or more of aortic constriction was more highly correlated with smooth muscle alpha-actin gene activation (r = 0.852; P = 0.0001) than with skeletal muscle alpha-actin (r = 0.532; P = 0.009); P less than 0.0005 for the difference in the correlation coefficients. Thus, smooth muscle alpha-actin is a molecular marker of the presence and extent of pressure-overload hypertrophy, whose correlation with cardiac growth at least equals that of skeletal alpha-actin. Induction of smooth muscle alpha-actin was delayed and sustained after aortic constriction, whereas the nuclear oncogenes c-jun and junB were expressed rapidly and transiently, providing potential dimerization partners for transcriptional control by c-fos. PMID:1834699

Black, F M; Packer, S E; Parker, T G; Michael, L H; Roberts, R; Schwartz, R J; Schneider, M D

1991-11-01

242

Self-consistent modeling of the flow behavior of wrought alpha\\/beta titanium alloys under isothermal and nonisothermal hot-working conditions  

Microsoft Academic Search

A self-consistent model was applied to predict the plastic flow behavior during hot working of alpha\\/beta titanium alloys\\u000a with wrought (equiaxed alpha) microstructures as a function of the flow behavior and volume fractions of the individual phases.\\u000a For this purpose, constitutive relations that incorporated composition-dependent strength coefficients were determined for\\u000a the alpha and beta phases. With these constitutive relations and

S. L. Semiatin; F. Montheillet; G. Shen; J. J. Jonas

2002-01-01

243

Electron-Ion Recombination Rate Coefficients, Photoionization Cross Sections, and Ionization Fractions for Astrophysically Abundant Elements. II. Oxygen Ions  

Microsoft Academic Search

A comprehensive and self-consistent set of new atomic data for photoionization cross sections, sigma_PI, and total unified recombination rate coefficients, alpha_R(T), of oxygen ions are obtained. The calculations are carried out in the close coupling approximation employing the R-matrix method. The unified treatment of total recombination includes both the radiative and dielectronic processes. The analysis of astrophysical spectra and ionization

Sultana N. Nahar

1999-01-01

244

Satellite Ballistic Coefficients and the Lower Thermosphere  

NASA Astrophysics Data System (ADS)

The observed variations in the 'estimated' ballistic coefficients (B') for low-perigee satellites in the lower thermosphere (about 200 km) during the year 2001, have been used to study their implications for neutral atmospheric densities with respect to changes in the solar activity and geomagnetic activity. The changes in B' reflect the unmodeled corrections in the atmospheric density models. It is shown that statistically, on the average, based on the 'true' ballistic coefficients (Bt), the atmospheric density models predict the 'true' density within 10 percent as a function of solar activity for quiet and mild geomagnetic periods. The observed variations in the ballistic coefficients with days exhibit a semiannual variation (SAV). The 'scaling' factor required to correctly predict the SAV in the 'true' densities from the model densities, ranges from a maximum of about 1.13 in the spring (equinox) to a minimum of about 0.93 in the summer (solstice), implying a semiannual amplitude(SAA) of (max/min) 1.2. The calculations based on the CIRA-86 models show that changes in B' during some major magnetic storms cannot be explained, as they are probably contaminated by 'high density neutral cells' observed by the S85-1 satellite at 200 km and predicted by the NCAR-TIGCM models by Crowley, et al (1995). Changes in B' due to these cells all the more require temperature/density corrections of the steady-state High Accuracy Satellite Drag Model (HASDM). It is suggested that the NCAR-TIGCM model should be used to see if it performs better in bringing the B' values closer to Bt than the steady-state models.

Bhatnagar, V. P.; Germany, G. A.; Tan, A.; Wu, S. T.

2004-12-01

245

Triplicated alpha-globin loci in humans.  

PubMed

We have identified 12 individuals who are heterozygous for a chromosome with three alpha-globin genes. We determined the presence of the third alpha-globin locus by restriction endonuclease digestion and hybridization with alpha-globin cDNA probes. The three alpha-globin loci resided in an elongated fragment on digestion with EcoRI, BamHI, and Xba I, and the third locus was present in an additional 3.7-kilobase fragment on digestion with Hpa I, Sac I, and Bgl II. The locations of the restriction sites are compatible with a nonhomologous crossover mechanism producing the triple alpha loci. The frequency of the triple alpha loci was 0.0036 in American blacks and less than 0.004 in Sardinians, but was higher in Greek Crypriots (0.05). Individuals with five alpha-globin genes (alpha alpha/alpha alpha alpha) apparently showed no clinical or hematologic abnormalities. PMID:6928643

Goossens, M; Dozy, A M; Embury, S H; Zachariades, Z; Hadjiminas, M G; Stamatoyannopoulos, G; Kan, Y W

1980-01-01

246

Surfaces with adaptive radar reflection coefficients  

NASA Astrophysics Data System (ADS)

Conventional (passive) radar-absorbing materials (RAM) have been in use now for over half a century, but it is only with recent advances in conducting polymer composite materials that large-area surfaces having controllable reflection coefficients at radar frequencies have become practicable. Techniques for utilizing these new materials in re-configurable electromagnetic, or `smart', surfaces are reviewed, with due emphasis given to the problem of system integration. The discussion is complemented by modelled and measured performance data on several smart surface configurations.

Chambers, Barry

1997-10-01

247

Sensitivity coefficients for matrix-based LCA  

Microsoft Academic Search

Background, aim, and scope  Matrix-based life cycle assessment (LCA) is part of the standard ingredients of modern LCA tools. An important aspect of matrix-based\\u000a LCA that is straightforward to carry out, but that requires a careful mathematical handling, is the inclusion of sensitivity\\u000a coefficients based on differentiating the matrix-based formulas.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  We briefly review the basic equations for LCA and

Reinout Heijungs

2010-01-01

248

Coefficient of restitution for wet impacts  

NASA Astrophysics Data System (ADS)

As the experience of playing football in the rain may tell, wetting could influence the coefficient of restitution (COR) dramatically. This is due to the extra energy dissipation from the wetting liquid, for instance viscous damping. To unveil the underlying mechanisms accounting for the influence, we study experimentally the COR by tracing free falling particles bouncing on a wet surface. The dependance of the COR on the impact velocity, various particle and liquid properties will be presented and discussed in terms of dimensionless Stokes' and capillary numbers.

Gollwitzer, Frank; Huang, Kai; Krülle, Christof A.; Rehberg, Ingo

2012-02-01

249

Coefficient of restitution for wet particles.  

PubMed

The influence of a liquid film on the coefficient of restitution (COR) is investigated experimentally by tracing freely falling particles bouncing on a wet surface. The dependence of the COR on the impact velocity and various properties of the particle and liquid is presented and discussed in terms of dimensionless numbers that characterize the interplay between inertial, viscous, and surface forces. In the Reynolds number regime where lubrication theory does not apply, the ratio of the film thickness to the particle size is found to be a crucial parameter determining the COR. PMID:23005407

Gollwitzer, Frank; Rehberg, Ingo; Kruelle, Christof A; Huang, Kai

2012-07-09

250

Micro-Fluidic Diffusion Coefficient Measurement  

SciTech Connect

A new method for diffusion coefficient measurement applicable to micro-fluidics is pre- sented. The method Iltilizes an analytical model describing laminar dispersion in rect- anglllar ~llicro_channe]s. The Illethod ~vas verified throllgh measllremen~ of fllloresceill diffusivity in water and aqueolls polymer solutions of differing concentration. The diffll- sivity of flllorescein was measlmed as 0.64 x 10-gm2/s in water, 0.49 x 10-gm2/s in the 4 gm/dl dextran solution and 0.38 x 10-9n12/s in the 8 gnl/dl dextran solution.

Forster, F.K.; Galambos, P.

1998-10-06

251

Third-harmonic coefficient of Li+  

Microsoft Academic Search

Accurate and coupled Hartree-Fock calculations of the third-harmonic coefficient (THC) of Li+ are presented. The zero-frequency THC in the Hartree-Fock case is 0.2190 a.u. and the accurate THC is 0.2411 a.u. The 1s2-->1s2p transition wavelength is determined to be 196.7 Å from the Hartree- Fock calculation and 199.0 Å from the accurate calculation, whereas the observed value is 199.3 Å.

R. Klingbeil; V. G. Kaveeshwar; R. P. Hurst

1974-01-01

252

Coefficient of restitution for wet particles  

NASA Astrophysics Data System (ADS)

The influence of a liquid film on the coefficient of restitution (COR) is investigated experimentally by tracing freely falling particles bouncing on a wet surface. The dependence of the COR on the impact velocity and various properties of the particle and liquid is presented and discussed in terms of dimensionless numbers that characterize the interplay between inertial, viscous, and surface forces. In the Reynolds number regime where lubrication theory does not apply, the ratio of the film thickness to the particle size is found to be a crucial parameter determining the COR.

Gollwitzer, Frank; Rehberg, Ingo; Kruelle, Christof A.; Huang, Kai

2012-07-01

253

Second order hydrodynamic coefficients from kinetic theory  

SciTech Connect

In a relativistic setting, hydrodynamic calculations which include shear viscosity (which is first order in an expansion in gradients of the flow velocity) are unstable and acausal unless they also include terms to second order in gradients. To date such terms have only been computed in supersymmetric N=4 super-Yang-Mills theory at infinite coupling. Here we compute these second-order hydrodynamic coefficients in weakly coupled QCD, perturbatively to leading order in the QCD coupling, using kinetic theory. We also compute them in QED and scalar {lambda}{phi}{sup 4} theory.

York, Mark Abraao; Moore, Guy D. [McGill University, Department of Physics, 3600 rue University, Montreal QC H3A 2T8 (Canada)

2009-03-01

254

Studies of Gaseous Multiplication Coefficient in Isobutane  

SciTech Connect

This work presents the studies of gaseous multiplication coefficient behavior for isobutane, as function of the reduced electric field, by means of signal amplitude analysis. The experimental method used is based on the Pulsed Townsend technique, which follows from Townsend equation solution for a uniform electric field. In our configuration, the anode is made of a high resistivity (2.10{sup 12} OMEGA.cm) glass, while the cathode is of aluminium. In order to validate the technique and to analyze effects of non-uniformity, results for nitrogen, which has well-established data available in literature, are also presented.

Lima, Iara B.; Vivaldini, Tulio C. [Instituto de Pesquisas Energeticas e Nucleares, 05508-000, Cidade Universitaria, Sao Paulo (Brazil); Goncalves, Josemary A. C.; Botelho, Suzana; Bueno Tobias, Carmen C. [Instituto de Pesquisas Energeticas e Nucleares, 05508-000, Cidade Universitaria, Sao Paulo (Brazil); Departamento de Fisica, Pontificia Universidade Catolica de Sao Paulo, 01303-050, Sao Paulo (Brazil); Ridenti, Marco A.; Pascholati, Paulo R. [Instituto de Fisica, Universidade de Sao Paulo, 05508-090, Cidade Universitaria, Sao Paulo (Brazil); Fonte, Paulo; Mangiarotti, Alessio [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Departamento de Fisica da Universidade de Coimbra, 3004-516, Coimbra (Portugal)

2010-05-21

255

Bounds on Transport Coefficients of Porous Media  

SciTech Connect

An analytical formulation of conductivity bounds by Bergman and Milton is used in a different way to obtain rigorous bounds on the real transport coefficients (electrical conductivity, thermal conductivity, and/or fluid permeability) of a fluid-saturated porous medium. These bounds do not depend explicitly on the porosity, but rather on two formation factors--one associated with the pore space and the other with the solid frame. Hashin-Shtrikman bounds for transport in random polycrystals of porous-material laminates will also be discussed.

Berryman, J G

2005-03-21

256

Radiative corrections to the muonium hyperfine structure. II. The {alpha}(Z{alpha}){sup 2} correction  

SciTech Connect

This is the second of a series of papers on the radiative corrections of order {alpha}{sup 2}(Z{alpha}), {alpha}(Z{alpha}){sup 2}, and various logarithmic terms of order {alpha}{sup 4}, to the hyperfine structure of the muonium ground state. This paper deals with the {alpha}(Z{alpha}){sup 2} correction. Based on the NRQED bound state theory, we isolated the term of order {alpha}(Z{alpha}){sup 2} exactly. Our result +16.9042(11){alpha}(Z{alpha}){sup 2}E{sub F}/{pi} for the non-logarithmic part is consistent with the {alpha}(Z{alpha}){sup 2} part of Sapirstein{close_quote}s calculation and the recent result of Pachucki, and reduces the numerical uncertainty in the {alpha}(Z{alpha}){sup 2} term by 2 orders of magnitude. {copyright} {ital 1997} {ital The American Physical Society}

Nio, M. [Graduate School of Human Culture, Nara Womens University, Nara 630 (Japan); Kinoshita, T. [Newman Laboratory of Nuclear Studies, Cornell University, Ithaca, New York 14853 (United States)

1997-06-01

257

The Lift Coefficient of a Thin Jet-Flapped Wing. II. A Solution of the Integro-Differential Equation for the Slope of the Jet  

Microsoft Academic Search

In an earlier paper with the same general title (Spence 1956, referred to as I), a mathematical model was developed to discuss the flow past a two-dimensional wing at incidence alpha in a steady incompressible stream, with a jet of momentum coefficient C_J emerging from the trailing edge at an angular deflexion tau to the chordline. In linearized approximation it

D. A. Spence

1961-01-01

258

Coefficient of Restitution of Adhesively Bound Aggregates  

NASA Astrophysics Data System (ADS)

Dry granular gases are characterized by dissipative interactions of grains whereas usually attractive forces are neglected. Here we concern attractive-adhesive contacts between the constituents of the granular gas in order to quantify their influence on the cluster formation and the establishment of a steady aggregate size-distribution in driven systems. In this context the dynamics of dense planetary rings is our major concern. These disks are dynamically dominated by a balance between viscous (collisional) heating, driven by the Kepler-shear, counteracted by granular collisional cooling so that a stationary granular temperature may establish. In this work we concentrate on the aggregate aggregate collisions, where we try to analyze the dependence of the coefficient of restitution of the aggregate on its size and internal configuration. We show that the coefficient of restitution of a single constituent differs drastically when we combine them into an aggregate. We believe that this effect plays a crucial role on the collision dynamics of the ring material. We gratefully acknowledge financial support from the grant Sp384/22-1 (DFG).

Baibolatov, Yernur; Spahn, F.

2012-10-01

259

Ionization coefficient measurements in DC microplasmas  

NASA Astrophysics Data System (ADS)

While steady state Townsend discharges may provide data for ionization coefficients those are often not as accurate as those produced in dedicated pulsed current growth experiments. In this paper we show that one may be able to measure ionization coefficients in DC microdischarges that are of excellent quality. Measurements were made for argon and argon/nitrogen mixtures with different gas flow rates. The technique based measuring the spatial profile of emission a Townsend discharge. In spite of having the drift length of only 1 mm, excellent agreement has been found between our new measurements and the data for low-pressure, larger dimension (2-4cm) discharges in argon (Jelenak et al) for the E/N in the range from 300 Td to 4000 Td, where E/N is normalized electrical field strength. Below 300 Td our measured values are larger then those by Jelenak et al. This discrepancy with previous measurements will be discussed. The influence of the gas flow-rate and nitrogen concentration on the radial discharge profile in the Townsend mode will also be presented and discussed. Jelenak et al 1993 Phys. Rev. E 47 3566

Stefanovic, Ilija; Kuschel, Thomas; Winter, Joerg; Maric, Dragana; Petrovic, Zoran Lj.

2012-10-01

260

Shear viscosity coefficient from microscopic models  

NASA Astrophysics Data System (ADS)

The transport coefficient of shear viscosity is studied for a hadron matter through microscopic transport model, the ultrarelativistic quantum molecular dynamics (UrQMD), using the Green-Kubo formulas. Molecular-dynamical simulations are performed for a system of light mesons in a box with periodic boundary conditions. Starting from an initial state composed of ?,?,?,?,? with a uniform phase-space distribution, the evolution takes place through elastic collisions, production, and annihilation. The system approaches a stationary state of mesons and their resonances, which is characterized by common temperature. After equilibration, thermodynamic quantities such as the energy density, particle density, and pressure are calculated. From such an equilibrated state the shear viscosity coefficient is calculated from the fluctuations of stress tensor around equilibrium using Green-Kubo relations. We do our simulations here at zero net baryon density so that the equilibration times depend on the energy density. We do not include hadron strings as degrees of freedom so as to maintain detailed balance. Hence we do not get the saturation of temperature but this leads to longer equilibration times.

Muronga, Azwinndini

2004-04-01

261

Coefficient adaptive triangulation for strongly anisotropic problems  

SciTech Connect

Second order elliptic partial differential equations arise in many important applications, including flow through porous media, heat conduction, the distribution of electrical or magnetic potential. The prototype is the Laplace problem, which in discrete form produces a coefficient matrix that is relatively easy to solve in a regular domain. However, the presence of anisotropy produces a matrix whose condition number is increased, making the resulting linear system more difficult to solve. In this work, we take the anisotropy into account in the discretization by mapping each anisotropic region into a ``stretched`` coordinate space in which the anisotropy is removed. The region is then uniformly triangulated, and the resulting triangulation mapped back to the original space. The effect is to generate long slender triangles that are oriented in the direction of ``preferred flow.`` Slender triangles are generally regarded as numerically undesirable since they tend to cause poor conditioning; however, our triangulation has the effect of producing effective isotropy, thus improving the condition number of the resulting coefficient matrix.

D`Azevedo, E.F.; Romine, C.H.; Donato, J.M.

1996-01-01

262

Virial coefficients of Lennard-Jones mixtures  

NASA Astrophysics Data System (ADS)

We report results of calculations of the second through sixth virial coefficients for four prototype Lennard-Jones (LJ) mixtures that have been the subject of previous studies in the literature. Values are reported for temperatures ranging from T=0.6 to T=10.0, where here the temperature is given units of the LJ energy parameter of one of the components. Thermodynamic stability of the mixtures is studied using the virial equation of state (VEOS) with the calculated coefficients, with particular focus on characterizing the vapor-liquid critical behavior of the mixtures. For three of the mixtures, vapor-liquid coexistence and critical data are available for comparison at only one temperature, while for the fourth we can compare to a critical line. We find that the VEOS provides a useful indication of the presence and location of critical behavior, although in some situations we find need to consider ``near-miss'' critical behavior, where the classical conditions of criticality are nearly but not exactly satisfied.

Schultz, Andrew J.; Kofke, David A.

2009-06-01

263

Alpha 1 -antitrypsin and alpha 2 -macroglobulin in newborn infants  

Microsoft Academic Search

The following tests were performed within the first week of life in 129 newborn infants: determination of alpha1-antitrypsin, alpha2-macroglobulin, antithrombin III, fibrinogen, prothrombin, accelerin, convertin and plasminogen. The newborns were divided into three groups: group (a), healthy newborns with a normal obstetric history (n=62); group (b), newborns without clinical signs of illness, but a complicated obstetric history (n=49); group (c),

U. Göbel; A. Triebel; C. Petrich; H. Voss

1978-01-01

264

Comparison of field-measured radon diffusion coefficients with laboratory-measured coefficients  

SciTech Connect

Experiments were conducted to compare radon diffusion coefficients determined for 0.1-m depths of soils by a steady-state method in the laboratory and diffusion coefficients evaluated from radon fluxes through several-fold greater depths of the same soils covering uranium-mill tailings. The coefficients referred to diffusion in the total pore volume of the soils and are equivalent to values for the quantity, D/P, in the Generic Environmental Impact Statement on Uranium Milling prepared by the US Nuclear Regulatory Commission. Two soils were tested: a well-graded sand and an inorganic clay of low plasticity. For the flux evaluations, radon was collected by adsorption on charcoal following passive diffusion from the soil surface and also from air recirculating through an aluminum tent over the soil surface. An analysis of variance in the flux evaluations showed no significant difference between these two collection methods. Radon diffusion coefficients evaluated from field data were statistically indistinguishable, at the 95% confidence level, from those measured in the laboratory; however, the low precision of the field data prevented a sensitive validation of the laboratory measurements. From the field data, the coefficients were calculated to be 0.03 +- 0.03 cm/sup 2//s for the sand cover and 0.0036 +- 0.0004 cm/sup 2//s for the clay cover. The low precision in the coefficients evaluated from field data was attributed to high variation in radon flux with time and surface location at the field site.

Lepel, E.A.; Silker, W.B.; Thomas, V.W.; Kalkwarf, D.R.

1983-04-01

265

Solubilization and partial characterization of rat epididymal delta 4-steroid 5 alpha-reductase (cholestenone 5 alpha-reductase).  

PubMed Central

Epididymal delta 4-steroid 5 alpha-reductase (cholestenone 5 alpha-reductase), the enzyme that catalyses the conversion of testosterone into the biologically active metabolite dihydrotestosterone (17 beta-hydroxy-5 alpha-androstan-3-one), is a membrane-bound enzyme found in both nuclear and microsomal subcellular fractions. In order to characterize epididymal delta 4-steroid 5 alpha-reductase, it was first necessary to solubilize the enzymic activity. Of the various treatments tested, a combination of 0.5% (w/v) Lubrol WX, 0.1 M-sodium citrate and 0.1 M-KCl maintained enzymic activity at control values and solubilized 66% of total epididymal delta 4-steroid 5 alpha-reductase activity in an active and stable form. The sedimentation coefficient of solubilized delta 4-steroid 5 alpha-reductase, as determined in continuous sucrose density gradients, was greater for the microsomal than for the nuclear enzyme (11.6S compared with 10.1S). Although the apparent Km values of the enzyme for testosterone were similar in nuclear and microsomal subcellular fractions (range 1.75 x 10(-7) - 4.52 x 10(-7)M), the apparent Km of the enzyme for NADPH was about 30-fold greater for the microsomal enzyme than for the nuclear enzyme. The apparent Km of the enzyme for either substrate was not significantly altered after solubilization. The relative capacity of steroids to inhibit the enzymic activity, the pH optima and the effects of Ca2+ and Mg2+ were similar for membrane-bound and solubilized delta 4-steroid 5 alpha-reductase in both the nuclear and the microsomal fractions. The results reported demonstrate that epididymal delta 4-steroid 5 alpha-reductase can be solubilized in an active and stable form with no significant changes in the kinetic characteristics of the enzyme after solubilization; furthermore, kinetic and molecular-size differences observed for the nuclear and the microsomal forms of the enzyme suggest that there may exist at least two forms of epididymal delta 4-steroid 5 alpha-reductase.

Scheer, H; Robaire, B

1983-01-01

266

Multiplicative duality, q-triplet and (?,?,q)-relation derived from the one-to-one correspondence between the (?,?)-multinomial coefficient and Tsallis entropy Sq  

NASA Astrophysics Data System (ADS)

We derive the multiplicative duality "q<->1/q" and other typical mathematical structures as the special cases of the (mu,nu,q)-relation behind Tsallis statistics by means of the (mu,nu)-multinomial coefficient. Recently the additive duality "q<->2-q" in Tsallis statistics is derived in the form of the one-to-one correspondence between the q-multinomial coefficient and Tsallis entropy. A slight generalization of this correspondence for the multiplicative duality requires the (mu,nu)-multinomial coefficient as a generalization of the q-multinomial coefficient. This combinatorial formalism provides us with the one-to-one correspondence between the (mu,nu)-multinomial coefficient and Tsallis entropy Sq, which determines a concrete relation among three parameters mu, nu and q, i.e., nu(1-mu)+1=q which is called "(mu,nu,q)-relation" in this paper. As special cases of the (mu,nu,q)-relation, the additive duality and the multiplicative duality are recovered when nu=1 and nu=q, respectively. As other special cases, when nu=2-q, a set of three parameters (mu,nu,q) is identified with the q-triplet (q_{sen},q_{rel},q_{stat}) recently conjectured by Tsallis. Moreover, when nu=1/q, the relation 1/(1-q_{sen})=1/alpha_{min}-1/alpha_{max} in the multifractal singularity spectrum f(alpha) is recovered by means of the (mu,nu,q)-relation.

Suyari, Hiroki; Wada, Tatsuaki

2008-01-01

267

Transport coefficients for the shear dynamo problem at small Reynolds numbers  

SciTech Connect

We build on the formulation developed in S. Sridhar and N. K. Singh [J. Fluid Mech. 664, 265 (2010)] and present a theory of the shear dynamo problem for small magnetic and fluid Reynolds numbers, but for arbitrary values of the shear parameter. Specializing to the case of a mean magnetic field that is slowly varying in time, explicit expressions for the transport coefficients {alpha}{sub il} and {eta}{sub iml} are derived. We prove that when the velocity field is nonhelical, the transport coefficient {alpha}{sub il} vanishes. We then consider forced, stochastic dynamics for the incompressible velocity field at low Reynolds number. An exact, explicit solution for the velocity field is derived, and the velocity spectrum tensor is calculated in terms of the Galilean-invariant forcing statistics. We consider forcing statistics that are nonhelical, isotropic, and delta correlated in time, and specialize to the case when the mean field is a function only of the spatial coordinate X{sub 3} and time {tau}; this reduction is necessary for comparison with the numerical experiments of A. Brandenburg, K. H. Raedler, M. Rheinhardt, and P. J. Kaepylae [Astrophys. J. 676, 740 (2008)]. Explicit expressions are derived for all four components of the magnetic diffusivity tensor {eta}{sub ij}({tau}). These are used to prove that the shear-current effect cannot be responsible for dynamo action at small Re and Rm, but for all values of the shear parameter.

Singh, Nishant K. [Raman Research Institute, Sadashivanagar, Bangalore 560 080 (India); Joint Astronomy Programme, Indian Institute of Science, Bangalore 560 012 (India); Sridhar, S. [Raman Research Institute, Sadashivanagar, Bangalore 560 080 (India)

2011-05-15

268

5-Alpha Reductase Inhibitor Information  

Center for Drug Evaluation (CDER)

... FDA Drug Safety Communication: 5-alpha reductase inhibitors (5-ARIs) may increase the risk of a more serious form of prostate cancer 6/9/2011; ... More results from www.fda.gov/drugs/drugsafety/informationbydrugclass

269

Synthesis and herbicidal activity of novel alpha,alpha,alpha-trifluoro-m-tolyl pyridazinone derivatives.  

PubMed

A series of novel alpha,alpha,alpha-trifluoro-m-tolyl pyridazinone derivatives was synthesised. Herbicidal activities of the two intermediate compounds and 15 pyridazinone derivatives were evaluated through barnyardgrass and rape cup tests and Spirodela polyrrhiza (L.) Schleiden tests. Selected compounds were also evaluated under greenhouse conditions. Bleaching activities were observed at 10 microg ml(-1) and some compounds exhibited herbicidal activities at a rate of 300 g ha(-1). The relationship between crystal structures and herbicidal activities is discussed through a comparison of two compounds (5a and 5f). PMID:16602079

Xu, Han; Zou, Xiao-Mao; Zhu, You-Quan; Liu, Bin; Tao, Han-Lin; Hu, Xu-Hong; Song, Hai-Bin; Hu, Fang-Zhong; Wang, Yong; Yang, Hua-Zheng

2006-06-01

270

Warm {alpha}-nucleon matter  

SciTech Connect

The properties of warm dilute {alpha}-nucleon matter are studied in a variational approach in the Thomas-Fermi approximation starting from an effective two-body nucleon-nucleon interaction. The equation of state, symmetry energy, incompressibility of the said matter, and {alpha} fraction are in consonance with those evaluated from the virial approach, which sets the benchmark for such calculations at low densities.

Samaddar, S. K.; De, J. N. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)

2011-05-15

271

Alpha 1-adrenergic receptor structure  

Microsoft Academic Search

The structure of the alpha 1-adrenergic receptor was investigated by comparing polypeptides identified by sodium dodecyl sulfate (NaDodSO4)-polyacrylamide gel electrophoresis with the size of the intact receptor in cell membranes as determined by target size analysis. The alpha 1-adrenergic receptor from rat liver membranes affinity-labeled with (³H)phenoxybenzamine, a covalent affinity reagent, appeared as a single polypeptide with a molecular mass

J. C. Venter; P. Horne; B. Eddy; R. Greguski; C. M. Fraser

1984-01-01

272

Order-alphas2 QCD corrections to the deep inelastic proton structure functions F2 and FL  

Microsoft Academic Search

We present the calculation of the order-alphas2 correction to the deep inelastic coefficient functions Ci(x, Q2) (i=2, L). Its effect on the behaviour of the proton structure functions Fi(x, Q2) for fixed target and HERA energies is studied. We investigate the dependence of the O(alphas2) QCD corrected structure functions on the mass factorization scale and the specific parametrization chosen for

E. B. Zijlstra; W. L. van Neerven

1992-01-01

273

Do Gauss coefficients see the geomagnetic jerks  

NASA Astrophysics Data System (ADS)

Secular variation is defined as those changes in the geomagnetic field with a duration of order of decade and an origin in the Earth's magnetic field. Magnetic observations have revealed one of the main features of the secular variation, the geomagnetic jerks. These phenomena have been characterized using the data provided by the magnetic observatories. Here we present preliminary results of our study of jerks using geomagnetic field models. For long time period, the Jackson et al. (2000) model is used; for more recent period, models obtained from observatories data are analyzed. Wavelet analysis is applied to different Gauss coefficients (g10, g11, ...) series in order to find the existing singularities. These events are presented and discussed in correlation with previous studies.

Chambodut, A.; Mandea, M.; Hulot, G.

2003-04-01

274

Low temperature fired positive temperature coefficient resistors  

NASA Astrophysics Data System (ADS)

Through the addition of BN as a sintering aid, Y-doped BaTiO3-based positive temperature coefficient resistors (PTCR) can be fabricated at temperatures below 1200‡C, which is much lower than is required when conventional sintering aids such as silica or A12O3, SiO2, and TiO2 (AST) are used. In comparison with the PTCR containing SiO2, the low-temperature-fired thermistor shows an enhanced PTC effect and a much higher temperature of resistivity maximum. Electrical properties of the BN-added BaTiO3, (Ba,Sr)TiO3, and (Ba,Pb)TiO3 ceramics were discussed.

Ho, In-Chyuan; Hsieh, Huey-Lin

1994-05-01

275

Experimental investigation of the iodine partition coefficient  

SciTech Connect

Short-term values of the iodine partition coefficient (IPC) were evaluated experimentally by an air/water system over the following ranges of conditions: temperature = 25 to 70/sup 0/C, pH = 5 to 9, and iodine concentration = 10/sup -9/ to 10/sup -2/ kg iodine/m/sup 3/ H/sub 2/O. The experimental IPC values are relatively independent of temperature over the indicated range, but show a significant dependence on pH and iodine concentration. In basic solutions the short-term values are several orders of magnitude less than the true equilibrium values; in acid solutions, the differences are much less. These results are useful for predicting the disposition of iodine shortly (i.e., 1 to 10 h) after iodine has been released into an air/water environment.

Kelly, J.L.; Babad, C.J.; Mulder, R.U.

1985-11-01

276

Asymptotic normalization coefficients from ab initio calculations  

SciTech Connect

We present calculations of asymptotic normalization coefficients (ANCs) for one-nucleon removals from nuclear states of mass numbers 3{<=}A{<=}9. Our ANCs were computed from variational Monte Carlo solutions to the many-body Schroedinger equation with the combined Argonne v{sub 18} two-nucleon and Urbana IX three-nucleon potentials. Instead of computing explicit overlap integrals, we applied a Green function method that is insensitive to the difficulties of constructing and Monte Carlo sampling the long-range tails of the variational wave functions. This method also allows computation of the ANC at the physical separation energy, even when it differs from the separation energy for the Hamiltonian. We compare our results, which for most nuclei are the first ab initio calculations of ANCs, with existing experimental and theoretical results and discuss further possible applications of the technique.

Nollett, Kenneth M.; Wiringa, R. B. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2011-04-15

277

Asymptotic normalization coefficients from ab initio calculations.  

SciTech Connect

We present calculations of asymptotic normalization coefficients (ANCs) for one-nucleon removals from nuclear states of mass numbers 3 {le} A {le} 9. Our ANCs were computed from variational Monte Carlo solutions to the many-body Schroedinger equation with the combined Argonne v{sub 18} two-nucleon and Urbana IX three-nucleon potentials. Instead of computing explicit overlap integrals, we applied a Green function method that is insensitive to the difficulties of constructing and Monte Carlo sampling the long-range tails of the variational wave functions. This method also allows computation of the ANC at the physical separation energy, even when it differs from the separation energy for the Hamiltonian. We compare our results, which for most nuclei are the first ab initio calculations of ANCs, with existing experimental and theoretical results and discuss further possible applications of the technique.

Nollett, K. M.; Wiringa, R. B. (Physics)

2011-04-13

278

Structure coefficients for use in stellar analysis  

NASA Astrophysics Data System (ADS)

We present new values of the structural coefficients ? j , and related quantities, for realistic models of distorted stars in close binary systems. Our procedure involves numerical integration of Radau's equation for detailed structural data and we verified our technique by referring to the 8-digit results of Brooker & Olle (Mon. Not. R. Astron. Soc. 115:101, 1955) for purely mathematical models. We provide tables of representative values of ? j , and related quantities, for j=2,3,…,7 for a selection of Zero Age Stellar Main Sequence (ZAMS) stellar models taken from the EZWeb compilation of the Dept. of Astronomy, University of Wisconsin-Madison. We include also some preliminary comparisons of our findings with the results of Claret and Gimenez (Astron. Astrophys. 519:A57 2010) for some observed stars.

?nlek, Gülay; Budding, Edwin

2012-12-01

279

Piezoceramic HF Resonator with Zero Temperature Coefficient  

NASA Astrophysics Data System (ADS)

The ternary piezoelectric material Pb0.97Sr0.03[Zr0.458Ti0.452(Mn1/3Nb2/3)0.09]O3 in the tetragonal phase near the morphotropic phase boundary (MPB) was prepared in this study. By properly varying the sintering and poling conditions, the zero temperature coefficient of the resonant frequency of the thickness vibration mode can be reached due to the slight shift of the MPB region. The computed Bechmann number based on the principle of trapped energy revealed that the high-frequency resonators with electrode width of at least less than 1 mm are suggested corresponding to the plate thickness of 0.205 mm to exhibit better resonance performance due to the suppression of unwanted mode coupling.

Wu, Long; Lee, Yi-Yeh

1993-11-01

280

Octanol-Water Partition Coefficients by Capillary Electrophoresis.  

National Technical Information Service (NTIS)

We have investigated the use of capillary electrophoresis (CE) for the modeling of octanol-water partition coefficients. Reversed-phase liquid chromatography (RPLC) is likely the most used method for estimation of octanol-water partition coefficients, wit...

J. G. Dorsey

1997-01-01

281

Flexoelectric and elastic coefficients of odd and even homologous bimesogens  

NASA Astrophysics Data System (ADS)

It is known that bimesogenic liquid crystals exhibit a marked “odd-even” effect in the flexoelastic ratio (the effective flexoelectric coefficient to the average elastic coefficient), with the ratio being higher for the “odd-spaced” bimesogens (those with an odd number of alkyl groups in the spacer chain) than their neighboring even-spaced counterparts. To determine the contribution of each property to the flexoelastic ratio, we present experimental results on the flexoelectric and elastic coefficients of two homologous nonsymmetric bimesogens which possess odd and even alkyl spacers. Our results show that, although there are differences in the flexoelectric coefficients, there are substantially larger differences in the effective elastic coefficient. Specifically, the odd bimesogen is found to have both a low splay elastic coefficient and a very low bend elastic coefficient which, when combined, results in a significantly lower effective elastic coefficient and consequently a higher flexoelastic ratio.

Atkinson, Katie L.; Morris, Stephen M.; Castles, Flynn; Qasim, Malik M.; Gardiner, Damian J.; Coles, Harry J.

2012-01-01

282

ESTIMATING COTTON EVAPOTRANSPIRATION CROP COEFFICIENTS WITH A MULTISPECTRAL VEGETATION INDEX  

Technology Transfer Automated Retrieval System (TEKTRAN)

Crop coefficients are a widely used and universally accepted method for estimating the crop evapotranspiration (ETc) component in irrigation scheduling programs. However, uncertainties of generalized basal crop coefficient (Kcb) curves can contribute to ETc estimates that are substantially different...

283

Radon diffusion coefficients in soils of varying moisture content  

NASA Astrophysics Data System (ADS)

Radon is a naturally occurring radioactive gas that is generated in the Earth's crust and is free to migrate through soil and be released to the atmosphere. Due to its unique properties, soil gas radon has been established as a powerful tracer used for a variety of purposes, such as exploring uranium ores, locating geothermal resources and hydrocarbon deposits, mapping geological faults, predicting seismic activity or volcanic eruptions and testing atmospheric transport models. Much attention has also been given to the radiological health hazard posed by increased radon concentrations in the living and working environment. In order to exploit radon profiles for geophysical purposes and also to predict its entry indoors, it is necessary to study its transport through soils. Among other factors, the importance of soil moisture in such studies has been largely highlighted and it is widely accepted that any measurement of radon transport parameters should be accompanied by a measurement of the soil moisture content. In principle, validation of transport models in the field is encountered by a large number of uncontrollable and varying parameters; laboratory methods are therefore preferred, allowing for experiments to be conducted under well-specified and uniform conditions. In this work, a laboratory technique has been applied for studying the effect of soil moisture content on radon diffusion. A vertical diffusion chamber was employed, in which radon was produced from a 226Ra source, was allowed to diffuse through a soil column and was finally monitored using a silicon surface barrier detector. By solving the steady-state radon diffusion equation, diffusion coefficients (D) were determined for soil samples of varying moisture content (m), from null (m=0) to saturation (m=1). For dry soil, a D value of 4.1×10-7 m2s-1 was determined, which increased moderately by a factor of ~3 for soil with low moisture content, i.e. up to m ~0.2. At higher water fractions, a decrease in D was initiated and became particularly pronounced approaching complete saturation; at m =0.9, D was as low as 2×10-9 m2s-1. A series of field experiments has also been conducted using alpha-track CR-39 detectors to follow the moisture-dependence of radon diffusion through soil under natural conditions. Diffusion coefficients were determined as a function of surface soil moisture assuming a one-dimensional diffusive radon transport model. Comparison between results obtained by the two methods showed that laboratory studies may provide a good indication of radon diffusion coefficients to be expected in the field. However, values determined in the field were systematically lower than those assessed in the laboratory. This finding could be attributed to soil-dependent parameters, such as differences in pore space geometry between the soil used in laboratory experiments and the undisturbed soil. In the latter case, the higher degree of compaction imposes a more tortuous pathway to soil gas, while at the same time the diffusive gas flux is hindered by local-scale zones of higher bulk density or water content.

Papachristodoulou, C.; Ioannides, K.; Pavlides, S.

2009-04-01

284

COMPARISON OF TELEPHOTOMETER MEASUREMENTS OF EXTINCTION COEFFICIENTS WITH SCATTERING AND ABSORPTION COEFFICIENTS  

EPA Science Inventory

During the summer of 1979, coefficients for light extinction in the atmosphere were calculated from measurements made with a telephotometer placed 251 m from a black target in Research Triangle Park, North Carolina. The results are well correlated (r = 0.92 to 0.96) with integrat...

285

Characterization of alpha-cordierite glass-ceramics from fly ash.  

PubMed

Batches of alpha-cordierite glass-ceramics, designated as GC-I and GC-II, containing 68 and 64 wt.% fly ash, respectively, were crystallized in the temperature range of 1125-1320 degrees C. The XRD (X-ray powder diffractometer) of the glass-ceramics show that alpha-cordierite became the dominant phase in GC-I and GC-II at 1200 degrees C. GC-I and GC-II, whose solid parts contain 74 and 78 vol.% alpha-cordierite and whose compressive strengths are 35 and 50 MPa, respectively, have the respective linear thermal expansion coefficients of 1.51x10(-6) and 1.43x10(-6)/ degrees C. The fly ash alpha-cordierite glass-ceramics can be employed as kiln furniture, honeycomb substrates for catalysts, and heat exchangers. PMID:15811690

He, Yong; Cheng, Weimin; Cai, Hesheng

2005-04-11

286

Pure E2 transitions: A test for BRICC Internal Conversion Coefficients  

SciTech Connect

The most widely used theoretical internal conversion coefficient (ICC) tables are of Hager and Seltzer (HS), Rosel et al. and BRICC (Band et al. tables using BRICC interpolation code). A rigorous comparison of experimental ICCs with various theoretical tabulations is possible only when a large data on experimental ICCs is available at one place. For this reason, a compilation of all the available experimental ICCs, {alpha}{sub T}, {alpha}{sub K}, {alpha}{sub L} of E2 transitions for a number of elements in the range of 24{<=}Z{<=}94 is presented. Listing of experimental data includes 595 datasets corresponding to 505 E2 transitions in 165 nuclei across the nuclear chart. Data with less than 10% experimental uncertainty have been selected for comparison with the theoretical values of Hager and Seltzer, Rosel et al. and BRICC. The relative percentage deviation (%{delta}) have been calculated for each of the above theories and the average (%{delta}) are estimated. The Band et al. tables, using the BRICC interpolation code are seen to give theoretical ICCs closest to experimental values.

Gerl, J. [Gesellschaft fur Schwerionenforschung, GSI, 64291 Darmstadt (Germany); Sai, K. Vijay; Sainath, M.; Gowrishankar, R.; Venkataramaniah, K. [Department of Physics, Sri Sathya Sai University, Prasanthinilayam 515134, AP (India)

2009-01-28

287

Frequency Effects in Tilting-Pad Journal Bearing Dynamic Coefficients  

Microsoft Academic Search

This paper examines the effects of damped vibrational frequencies on the linear reduced dynamical stiffness and damping coefficients of tilting-pad journal bearings. The frequency ratio (damped frequency\\/running speed) can be used to judge the accuracy of employing synchronously reduced linear coefficients in rotordynamic stability analyses. The use of these coefficients can result in simpler formulations of the system dynamical equations

J. K. Parsell; P. E. Allaire; L. E. Barrett

1983-01-01

288

Likelihood-based inference for genetic correlation coefficients  

Microsoft Academic Search

We review Wright's original definitions of the genetic correlation coefficients FST, FIT, and FIS, pointing out ambiguities and the difficulties that these have generated. We also briefly survey some subsequent approaches to defining and estimating the coefficients. We then propose a general framework in which the coefficients are defined, their properties established, and likelihood-based inference implemented. Likelihood methods of inference

David J. Balding

2003-01-01

289

Image denoising algorithm based on the relevance of wavelet coefficients  

Microsoft Academic Search

In this paper the wavelet transform and the wavelet transform theory have been elaborated. A wavelet coefficients' model in which individual shrinkage thresholds are selected for each coefficient has been established. The relationships between different wavelet coefficients are analyzed. According to this new model, a new algorithm of image denosing has been proposed. It is shown in the experiments that

Yan Ha

2009-01-01

290

A linear regression model using triangular fuzzy number coefficients  

Microsoft Academic Search

Fuzzy regression analysis using fuzzy linear models with symmetric triangular fuzzy number coefficients has been formulated earlier. The goal of this regression is to find the coefficients of a proposed model for all given input-output data sets. In this paper, we extend the results of a fuzzy linear regression model that uses symmetric triangular coefficient to one with non-symmetric fuzzy

K. K. Yen; S. Ghoshray; G. Roig

1999-01-01

291

Calculating a robust correlation coefficient and quantifying its uncertainty  

NASA Astrophysics Data System (ADS)

Relationships between primary and secondary data are frequently quantified using the correlation coefficient; however, traditional means of calculating experimental correlation coefficients are known to be adversely affected by outlier data. A new method for calculating a robust correlation coefficient is proposed based on a weighted average correlation calculated from different combinations or subsets of the original data. The proposed robust correlation coefficient is shown to have a higher breakdown point than either Pearson's or Spearman's correlation coefficients as well as two out of three other robust correlation coefficients. The least median of squares (LMS) correlation coefficient has the highest possible breakdown point; however, it also tends to give unrealistically high or low correlation coefficients. A simulation study demonstrates the differences between the proposed robust correlation coefficient and other robust correlation coefficients. When the sample size is small, the uncertainty in the measured correlation can be very large, especially when the measured correlation is low. The uncertainty in the correlation coefficient is calculated based on the measured correlation and the number of data. This sampling distribution for the correlation coefficient requires a number of independent data; however, earth sciences data are often spatially dependent. Thus, a method for calculating an effective number of independent data using the variogram is proposed. An example is presented that applies the developed techniques to a petroleum geostatistics problem. The methodologies presented in this paper are implemented in FORTRAN code made available as part of this paper.

Niven, Eric B.; Deutsch, Clayton V.

2012-03-01

292

Determination of alpha preformation for heavy nuclei  

Microsoft Academic Search

The alpha preformation factor and the penetration probability have been analyzed for heavy even-even nuclei in the frame of double folding model using the experimental released energies and alpha decay half-lives. The alpha preformation factors are compared with Po, Rn, Ra isotopes as well as Cm, Cf, Fm, No, Rf isotopes, respectively. It is shown that the alpha preformation factor

G. L. Zhang; X. Y. Le; H. Q. Zhang

2009-01-01

293

Removal of Arg141 from the alpha chain of human hemoglobin by carboxypeptidases N and M.  

PubMed

Both human plasma carboxypeptidase N (CPN) and membrane-bound carboxypeptidase M (CPM) released the C-terminal arginine (alpha-Arg141) of the alpha chain of human adult hemoglobin. An arginase contamination present in the hemoglobin preparation, which converted the released arginine to ornithine, was removed by gel filtration. CPM was about 20 times more efficient than CPN or its active subunit in hydrolyzing oxyhemoglobin and cleaved oxyhemoglobin twice as fast as deoxyhemoglobin. The hydrolysis of the peptide bond of alpha-Arg141 accelerated the dissociation rate of the tetramer deoxy-des-alpha-Arg141 hemoglobin to dimers 2500-fold over that of deoxyhemoglobin, as measured by haptoglobin binding. Moreover, the dissociation of the deoxy-des-alpha-Arg141 hemoglobin tetramer to dimers was not affected by 2,3-diphosphoglyceric acid. Des-alpha-Arg141 hemoglobin had a higher oxygen affinity (P50, 5.51 mm Hg; control, 19.94 mm Hg [P50 is the partial pressure of oxygen that gives 50% of the saturation of hemoglobin]) and a lower apparent cooperativity (Hill coefficient: n, 1.02; control, 2.24) than unhydrolyzed hemoglobin. After hemoglobin was incubated in human plasma, its oxygen-binding parameters, the P50, and the Hill coefficient decreased drastically due to cleavage by CPN. In the perfused rat heart, des-alpha-Arg141 hemoglobin was a more effective coronary vasoconstrictor than hemoglobin, possibly because it dissociated to dimers in the coronary vascular bed. A covalently cross-linked hemoglobin was less active than native hemoglobin. The coronary vasoconstriction was caused by multiple factors, including interference with vasodilation by nitric oxide and eicosanoids. Thus, the hydrolysis of hemoglobin by CPM and CPN demonstrated the contribution of the alpha-Arg141 residue to sustaining the tetrameric structure of hemoglobin and its normal oxygen affinity and vasoactivity. PMID:8635221

Michel, B; Igi?, R; Leray, V; Deddish, P A; Erdös, E G

1996-04-01

294

DETERMINATION OF OCTANOL/WATER DISTRIBUTION COEFFICIENTS, WATER SOLUBILITIES, AND SEDIMENT/WATER PARTITION COEFFICIENTS FOR HYDROPHOBIC ORGANIC POLLUTANTS  

EPA Science Inventory

Octanol/water distribution coefficients, water solubilities, and sediment/water partition coefficients are basic to any assessment of transport or dispersion of organic pollutants. In addition, these determinations are prerequisites for many chemical or biological process studies...

295

Impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data  

NASA Astrophysics Data System (ADS)

We present a study through extensive simulation that considers the impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data collected from media mimicking breast tissue. We found that while the impact of scattering heterogeneities/targets is modest on photoacoustic recovery of optical absorption coefficients, the impact of scattering contrast caused by adipose tissue, a layer of normal tissue along the boundary of the breast, is dramatic on reconstruction of optical absorption coefficients using photoacoustic data—up to 25.8% relative error in recovering the absorption coefficient is estimated in such cases. To overcome this problem, we propose a new method to enhance photoacoustic recovery of the optical absorption coefficient in heterogeneous media by considering inhomogeneous scattering coefficient distribution provided by diffuse optical tomography (DOT). Results from extensive simulations show that photoacoustic recovery of absorption coefficient maps can be improved considerably with a priori scattering information from DOT.

Li, Xiaoqi; Jiang, Huabei

2013-02-01

296

Impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data.  

PubMed

We present a study through extensive simulation that considers the impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data collected from media mimicking breast tissue. We found that while the impact of scattering heterogeneities/targets is modest on photoacoustic recovery of optical absorption coefficients, the impact of scattering contrast caused by adipose tissue, a layer of normal tissue along the boundary of the breast, is dramatic on reconstruction of optical absorption coefficients using photoacoustic data-up to 25.8% relative error in recovering the absorption coefficient is estimated in such cases. To overcome this problem, we propose a new method to enhance photoacoustic recovery of the optical absorption coefficient in heterogeneous media by considering inhomogeneous scattering coefficient distribution provided by diffuse optical tomography (DOT). Results from extensive simulations show that photoacoustic recovery of absorption coefficient maps can be improved considerably with a priori scattering information from DOT. PMID:23339968

Li, Xiaoqi; Jiang, Huabei

2013-01-23

297

Geostrophic drag coefficients over sea ice  

NASA Astrophysics Data System (ADS)

The geostrophic drag coefficient, Cg?u*/G, and turning angle, ? were measured October through November 1988 from a 120km array of 6 drifting buoys and a drifting ship in the northern Barents Sea/Arctic Ocean during CEAREX; u* is the friction velocity, G is the geostrophic wind, and ? is the angle between surface stress and . The median Cg was 0.029 with hinge values (quartiles) of 0.023 and 0.034 and the median ? was 25° with hinge values of 15° and 32°. The median values are representative for the nonsummer Arctic away from marginal seas and marginal ice zones. Surface air temperature, cloud amount, and the lapse rate above the inversion base were not good predictors of the influence of boundary layer stability on Cg. The geostrophic drag coefficient was most sensitive to the temperature difference across the boundary layer from the surface to the top of the inversion. A first order correction to account for airmass stability isThis stability correction represents a 17% improvement over using a constant drag value, based on reduction of variance with the CEAREX data set. The formula uses an external stability parameter, N9002, proportional to the difference between the potential temperature measured at 900mb, , which is representative of the temperature at the top of the arctic inversion, and at the surface, PS is surface pressure and g is gravity. can be obtained from atmospheric models or satellite-derived temperature soundings. Formulas are also developed based on the standard level of 850mb; the reduction in variance is less, 11%, because this level is sometimes above the top of the arctic inversion. We reason that because most of the boundary layer above the surface layer is near a critical Richardson number, the total amount of shear that can be maintained in the boundary layer, and thus the reduction in Cg, is given by the external temperature difference rather than the detailed internal structure of stratification and shear. Corrections are also proposed for change in surface roughness. Although the thermal wind was estimated from the buoy array and is important for case studies, it did not provide significant improvement in reducing the variability in the geostrophic drag measurements.

Overland, James E.; Davidson, Kenneth L.

1992-01-01

298

Modulation of gene expression by alpha-tocopherol and alpha-tocopheryl phosphate  

Technology Transfer Automated Retrieval System (TEKTRAN)

The naturally occurring vitamin E analogue, alpha-tocopheryl phosphate (alphaTP), has been reported to be more potent in reducing cell proliferation and the expression of the CD36 scavenger receptor than the un-phosphorylated alpha-tocopherol (alpha T). We have now assessed the effects of alpha T an...

299

Mechanism of alpha-tocopheryl-phosphate (alpha-TP) transport across the cell membrane  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have reported that alpha-TP is synthesized and hydrolyzed in animal cells and tissues; it modulates also several cell functions (FRBM 39:970, and UBMB Life, 57:23, 2005). While it is similar to alpha-tocopherol (alpha-T), alpha-TP appears to be more potent than alpha-T in inhibiting cell prolifer...

300

Closed string transport coefficients and the membrane paradigm  

NASA Astrophysics Data System (ADS)

I discuss a correspondence between a fictitious fluid in the black hole membrane paradigm and highly excited closed string states according to the black hole correspondence principle. I calculate the membrane transport coefficients of an electric Neveu-Schwarz-Neveu-Schwarz 2-charged black hole and transport coefficients of the highly excited closed string states which possess a Kaluza-Klein number and a winding number. Comparing both the transport coefficients at the correspondence point, I show that, except for the bulk viscosity, the membrane transport coefficients are of the same order as the transport coefficients of the closed string states on the stretched horizon. Also, I show that, except for the bulk viscosity, both the dimensionless transport coefficients, which are defined by dividing the transport coefficients by the entropy density, are exactly equal if the central charge is 6.

Sasai, Yuya

2011-11-01

301

Workshop on Precision Measurements of $\\alpha_s$  

SciTech Connect

These are the proceedings of the Workshop on Precision Measurements of {alpha}{sub s} held at the Max-Planck-Institute for Physics, Munich, February 9-11, 2011. The workshop explored in depth the determination of {alpha}{sub s}(m{sub Z}) in the {ovr MS} scheme from the key categories where high precision measurements are currently being made, including DIS and global PDF fits, {tau}-decays, electro-weak precision observables and Z-decays, event-shapes, and lattice QCD. These proceedings contain a short summary contribution from the speakers, as well as the lists of authors, conveners, participants, and talks.

Bethke, Siegfried; /Munich, Max Planck Inst.; Hoang, Andre H.; /Vienna U.; Kluth, Stefan; /Munich, Max Planck Inst.; Schieck, Jochen; /Munich U.; Stewart, Iain W.; Aoki, S.; Beneke, M.; Bethke, S.; Blumlein, J.; Brambilla, N.; Brodsky, S.; /MIT, LNS

2011-10-01

302

Testing the Correlated Random Coefficient Model*  

PubMed Central

The recent literature on instrumental variables (IV) features models in which agents sort into treatment status on the basis of gains from treatment as well as on baseline-pretreatment levels. Components of the gains known to the agents and acted on by them may not be known by the observing economist. Such models are called correlated random coe cient models. Sorting on unobserved components of gains complicates the interpretation of what IV estimates. This paper examines testable implications of the hypothesis that agents do not sort into treatment based on gains. In it, we develop new tests to gauge the empirical relevance of the correlated random coe cient model to examine whether the additional complications associated with it are required. We examine the power of the proposed tests. We derive a new representation of the variance of the instrumental variable estimator for the correlated random coefficient model. We apply the methods in this paper to the prototypical empirical problem of estimating the return to schooling and nd evidence of sorting into schooling based on unobserved components of gains.

Heckman, James J.; Schmierer, Daniel; Urzua, Sergio

2010-01-01

303

Asymmetrical slip propensity: required coefficient of friction  

PubMed Central

Background Most studies in performing slips and falls research reported their results after the ipsilateral leg of subjects (either right foot or left foot) was guided to contact the contaminated floor surface although many studies indicated concerns for asymmetries of legs in kinematic or kinetic variables. Thus, the present study evaluated if dominant leg’s slip tendency would be different from non-dominant leg’s slip tendency by comparing the Required Coefficient of Friction (RCOF) of the two lower limbs. Findings Forty seven health adults participated in the present study. RCOF was measured when left or right foot of subjects contacted the force platforms respectively. Paired t-test was performed to test if RCOF and heel velocity (HCV) of dominant legs was different from that of non-dominant legs. It was suggested that the asymmetry in RCOFs and HCV between the two lower limbs existed. The RCOFs of non-dominant legs were higher than that of dominant legs. Conclusions The results indicated that asymmetry in slip propensity, RCOF, was existed in lower extremity. The results from the study suggested that it would be benefit to include a variable, such as asymmetry, in slips and falls research.

2013-01-01

304

Pulmonary interstitial compliance and microvascular filtration coefficient.  

PubMed

Static and dynamic properties governing the fluid movement into the pulmonary interstitium were examined in isolated canine lobes. The system was driven by altering intravascular presure (Piv) when the lobe was isogravimetric (change in weight (W) = 0) and allowing the lobe to become isogravimetric again. By making use of an analogy to charging a capacitor across a resistor, calculation of the filtration coefficient for transvascular fluid movement (KF) and determination of the pressure-volume relationship of the pulmonary interstitial space (Pis-Vis), with a minimum of untested assumptions, was possible. KF was found to be the same for fluid moving out of or into the intravascular space, and when the relationship between Piv and alveolar pressure (PAlv) was constant, KF was independent of transpulmonary pressure (PL). When PAlv exceeded Piv, changes in Piv did not influence KF, suggesting no significant change in either surface area available for fluid transudation or vascular permeability. The Pis-Vis curve for increasing values of Vis and Pis is best described by an exponential relationhip and is independent of PL. However, the Pis-Vis curve with decreasing values of Vis and Pis is dependent on PL. PMID:7406055

Goldberg, H S

1980-08-01

305

Transport coefficients of soft repulsive particle fluids  

NASA Astrophysics Data System (ADS)

Molecular dynamics computer simulation has been used to compute the self-diffusion coefficient, D, and shear viscosity, ?s, of soft-sphere fluids, in which the particles interact through the soft-sphere pair potential, phi(r) = epsilon(?/r)n, where n measures the steepness or stiffness of the potential, epsilon and ? are a characteristic energy and distance, respectively. The simulations were carried out on monodisperse systems for a range of n values from the hard-sphere (n\\to \\infty ) limit down to n = 4 over a range of densities. An ideal glass transition value was estimated from the limit where D and \\eta_{\\mathrm {s}}^{-1}\\to 0 for each value of n. Nucleation of the crystalline phase was found to intervene prior to the formation of the glass itself, as has been found previously for hard spheres (i.e. n\\to \\infty ). With increasing softness the glass transition moves further within the solid part of the phase diagram, as predicted by Cardenas and Tosi (2005 Phys. Lett. A 336 423), although the volume fractions at the glass transition estimated by the current procedure here are systematically lower than the predictions of that study.

Heyes, D. M.; Bra?ka, A. C.

2008-03-01

306

Altitude Dependent Auroral Ion Diffusion Coefficients  

NASA Astrophysics Data System (ADS)

Simultaneous upgoing auroral H+ and O+ ion beams generate ion acoustic waves which have both parallel and oblique wave vectors with respect to the ambient magnetic field. A parallel mode is investigated with phase velocity UO + CO in the direction of beam propagation, where UO is the oxygen beam velocity and CO is the oxygen ion sound speed. Due to the mass difference, this mode preferentially resonates with the oxygen beam through the n = 1 cyclotron resonance, causing O+ ions to diffuse in a direction that is primarily perpendicular to the background magnetic field. The Landau resonance (n = 0) is very narrow in parallel velocity and does not interact with either ion beam. In one case study the parallel acoustic mode begins to resonate with O+ ions within the auroral acceleration region and this resonant region in velocity space sweeps through the entire O+ beam as it moves into weaker magnetic field regions. The O+ quasilinear diffusion coefficients are examined during this process. Perpendicular diffusion becomes significant when the parallel resonant velocity is close to the parallel group velocity of the waves. This selects regions of velocity space where perpendicular diffusion is maximum which occurs at the leading edge of the resonant region as it sweeps through the O+ beam. In k - space these resonant velocities correspond to the regions of peak growth rate. The relevance of this work to the selective energization of heavy auroral ion beams will be discussed.

Ludlow, G. R.

2011-12-01

307

Transport coefficients of soft repulsive particle fluids.  

PubMed

Molecular dynamics computer simulation has been used to compute the self-diffusion coefficient, D, and shear viscosity, ?(s), of soft-sphere fluids, in which the particles interact through the soft-sphere pair potential, ?(r) = ?(?/r)(n), where n measures the steepness or stiffness of the potential, ? and ? are a characteristic energy and distance, respectively. The simulations were carried out on monodisperse systems for a range of n values from the hard-sphere ([Formula: see text]) limit down to n = 4 over a range of densities. An ideal glass transition value was estimated from the limit where D and [Formula: see text] for each value of n. Nucleation of the crystalline phase was found to intervene prior to the formation of the glass itself, as has been found previously for hard spheres (i.e. [Formula: see text]). With increasing softness the glass transition moves further within the solid part of the phase diagram, as predicted by Cardenas and Tosi (2005 Phys. Lett. A 336 423), although the volume fractions at the glass transition estimated by the current procedure here are systematically lower than the predictions of that study. PMID:21694216

Heyes, D M; Bra?ka, A C

2008-02-20

308

Velocity slip and temperature jump coefficients for gaseous mixtures. III. Diffusion slip coefficient  

Microsoft Academic Search

The diffusion slip coefficient is calculated for binary gaseous mixtures on the basis of the McCormack kinetic model of the Boltzmann equation, which is solved by the discrete velocity method. The calculations are carried out for the three mixtures of noble gases: neon-argon, helium-argon, and helium-xenon. Two models of the intermolecular interaction potential were considered. It was shown that this

Felix Sharipov; Denize Kalempa

2004-01-01

309

Velocity slip and temperature jump coefficients for gaseous mixtures. I. Viscous slip coefficient  

Microsoft Academic Search

The viscous slip coefficient was calculated for binary gaseous mixtures on the basis of the McCormack kinetic model of the Boltzmann equation, which was solved by the discrete velocity method. The calculations were carried out for the three mixtures of noble gases: neon-argon, helium-argon, and helium-xenon. It was showed that for the mixture of helium and xenon, which has a

Felix Sharipov; Denize Kalempa

2003-01-01

310

Velocity slip and temperature jump coefficients for gaseous mixtures. II. Thermal slip coefficient  

Microsoft Academic Search

The thermal slip coefficient was calculated for a binary gaseous mixture on the basis of the McCormack kinetic model of the Boltzmann equation, which was solved by the discrete velocity method. The calculations were carried out for the three mixtures of noble gases: neon-argon, helium-argon, and helium-xenon. A strong influence of the potential of intermolecular interaction upon the thermal slip

Felix Sharipov; Denize Kalempa

2004-01-01

311

Application of response surface methodology to the modeling of alpha-amylase purification by aqueous two-phase systems.  

PubMed

Mathematical models concerning the purification of alpha-amylase from the cultivation supernatant of Bacillus subtilis in a polyethylene glycol-citrate aqueous two-phase system (ATP) are established with response surface methodology. The PEG3350, citrate and sodium chloride concentrations were selected as variables to evaluate the purification impact factors in aqueous two-phase system, including partition coefficients of alpha-amylase, total protein, purification factor and alpha-amylase yield. An experimental space with two-fold purification and over 90% yield of alpha-amylase is achieved through the optimized condition basing on the model. Two systems with low viscosity within said space were further selected to perform alpha-amylase purification and the experimental results coincide well with the calculation of the models, which indicates that the model provides a promising tool for experimental design of protein purification by aqueous two-phase system. PMID:15955584

Zhi, Wenbo; Song, Jiangnan; Ouyang, Fan; Bi, Jingxiu

2005-08-01

312

Validation of the Trait Anxiety Scale for State-Trait Anxiety Inventory in Suicide Victims and Living Controls of Chinese Rural Youths  

Microsoft Academic Search

This study evaluated the validation of STAI Trait-Anxiety Scale in suicide cases and community living controls in rural China. The participants were 392 suicides and 416 controls. Cronbach's Alpha was computed to evaluate the internal consistency. The Spearman Correlation Coefficient between Trait-Anxiety Scale and other instrument was calculated to evaluate the external validity, and the Exploratory Factor Analysis was used

Jie Zhang; Qi Gao

2012-01-01

313

Measuring Cultural Awareness in Nursing Students.  

ERIC Educational Resources Information Center

A multicultural awareness scale completed by 72 nursing students obtained a Cronbach's alpha reliability coefficient of .91. An expert panel analyzed content validity and the revised scale was completed by 118 students. Factor analysis supported the measure's construct validity. (Contains 30 references.) (SK)

Rew, Lynn; Becker, Heather; Cookston, Jeff; Khosropour, Shirin; Martinez, Stephanie

2003-01-01

314

Burnout bij fysiotherapeuten: Een psychometrische studie. \\/ Burnout among physiotherapists: A psychometric study  

Microsoft Academic Search

Studied the psychometric characteristics of the Dutch version of the Maslach Burnout Inventory. Human Ss: 341 normal male and 103 normal female Dutch adults (aged 24-62 yrs) (physiotherapists). The Cronbach alpha coefficient was used, and principal component factor analysis with varimax rotation was performed. The reliability and the internal consistency of the Emotional Exhaustion, Depersonalization, and Personal Accomplishment subscales was

Vries de T. A; J. Hoogstraten

1998-01-01

315

Psychometric Properties of the Minnesota Multiphasic Personality Inventory–Adolescent (MMPI–A) Clinical, Content, and Supplementary Scales in a Forensic Sample  

Microsoft Academic Search

In this study, we evaluated the internal psychometric properties and external correlates of scores on the Clinical, Content, and Supplementary scales in a forensic sample of 496 adolescents (315 boys and 181 girls) who were court-ordered to receive psychological evaluations. We examined Cronbach's alpha coefficients, scale intercorrelation matrices, and frequencies of scale elevations. Further, we found varying degrees of support

Richard W. Handel; Robert P. Archer; David E. Elkins; John A. Mason; Elise C. Simonds-Bisbee

2011-01-01

316

A series of lower bounds to the reliability of a test  

Microsoft Academic Search

Two well-known lower bounds to the reliability in classical test theory, Guttman's 2 and Cronbach's coefficient alpha, are shown to be terms of an infinite series of lower bounds. All terms of this series are equal to the reliability if and only if the test is composed of items which are essentially tau-equivalent. Some practical examples, comparing the first 7

J. M. F. ten Berge; Frits E. Zegers

1978-01-01

317

Farmers' Attitudes and Skills of Farm Business Management in Jordan  

ERIC Educational Resources Information Center

|This study aimed to investigate farmers' attitudes and skills of farm management. Two scales were constructed as an instrument for data collection, based on a sample of 100 farm units. Cronbach's alpha coefficients were 0.84 or higher, which indicated that the instrument scales were internally consistent. Non-parametric tests were used to analyze…

Al-Rimawi, Ahmad Sh.; Karablieh, Emad K.; Al-Qadi, Abdulfatah S.; Al-Qudah, Hussein F.

2006-01-01

318

Confirmatory Factor Analysis of Persian Adaptation of Multidimensional Students' Life Satisfaction Scale (MSLSS)  

ERIC Educational Resources Information Center

|Validity and reliability of Persian adaptation of MSLSS in the 12-18 years, middle and high school students (430 students in grades 6-12 in Bushehr port, Iran) using confirmatory factor analysis by means of LISREL statistical package were checked. Internal consistency reliability estimates (Cronbach's coefficient [alpha]) were all above the…

Hatami, Gissou; Motamed, Niloofar; Ashrafzadeh, Mahshid

2010-01-01

319

A Comparison of Ipsative and Normative Procedures in the Study of Cognitive Preferences.  

ERIC Educational Resources Information Center

Scores of high school students responding to the same biology cognitive preference test using both normative and ipsative procedures were compared. All subtests, whether ipsative or normative, had high alpha Cronbach coefficients. A number of similarities were found in the mean scores obtained by the two procedures, as well as moderate positive…

Tamir, Pinchas; Lunetta, Vincent N.

320

The Validation of a Food Label Literacy Questionnaire for Elementary School Children  

ERIC Educational Resources Information Center

|Objective: To determine the reliability and validity of a 10-item questionnaire, the Food Label Literacy for Applied Nutrition Knowledge questionnaire. Methods: Participants were elementary school children exposed to a 90-minute school-based nutrition program. Reliability was assessed via Cronbach alpha and intraclass correlation coefficient

Reynolds, Jesse S.; Treu, Judith A.; Njike, Valentine; Walker, Jennifer; Smith, Erica; Katz, Catherine S.; Katz, David L.

2012-01-01

321

Development of an instrument: Mentoring for effective primary science teaching  

Microsoft Academic Search

Perceptions of mentors' practices related to primary science teaching from nine Australian universities (N = 331 final-year preservice teachers) were gathered through a literature-based instrument. Five factors that characterize effective mentoring practices in primary science teaching were supported by confirmatory factory analysis. These factors, namely, personal attributes, system requirements, pedagogical knowledge, modeling, and feedback, had Cronbach alpha coefficients of internal

Peter Hudson; Keith Richard Skamp; Lyndon Owen Brooks

2005-01-01

322

Nonlocal potential form for s-wave (alpha)-(alpha) scattering.  

National Technical Information Service (NTIS)

Low energy s-wave (alpha)-(alpha) phase shifts that agree well with the measured set, have been extracted using a nonlocal interaction formed by folding (local real) nucleon -(alpha) particle interactions with density matrix elements of the (projectile) (...

K. Amos M. T. Bennett

1997-01-01

323

Binding of anhydrotrypsin to alpha 2-macroglobulin.  

PubMed Central

Radiolabelled anhydrotrypsin was bound by alpha 2M (alpha 2-macroglobulin) sufficiently tightly to resist separation during gel electrophoresis; 2 mol of anhydrotrypsin were bound/mol of alpha 2M, but the interaction differed in important respects from that between active proteinases and alpha 2M. Anhydrotrypsin was bound by the electrophoretically 'fast' form of alpha 2M, although much less effectively than by the 'slow' form. The inactive enzyme was displaced from alpha 2M by trypsin inhibitor, the order of effectiveness being aprotinin > soya-bean trypsin inhibitor > benzamidine. Saturation of alpha 2M with anhydrotrypsin did not prevent subsequent binding and inhibition of active trypsin by the alpha 2M, and the anhydrotrypsin was not displaced during this reaction. Anhydrotrypsin bound by alpha 2M retained its ability to react with antibodies against trypsin, whereas bound trypsin did not. Images Fig. 1. Fig. 2.

Sayers, C A; Barrett, A J

1980-01-01

324

Bremsstrahlung in {alpha} Decay Reexamined  

SciTech Connect

A high-statistics measurement of bremsstrahlung emitted in the {alpha} decay of {sup 210}Po has been performed, which allows us to follow the photon spectra up to energies of {approx}500 keV. The measured differential emission probability is in good agreement with our theoretical results obtained within the quasiclassical approximation as well as with the exact quantum mechanical calculation. It is shown that, due to the small effective electric dipole charge of the radiating system, a significant interference between the electric dipole and quadrupole contributions occurs, which is altering substantially the angular correlation between the {alpha} particle and the emitted photon.

Boie, H.; Scheit, H.; Jentschura, U. D.; Koeck, F.; Lauer, M.; Schwalm, D. [Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany); Milstein, A. I.; Terekhov, I. S. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation)

2007-07-13

325

Test chamber for alpha spectrometry  

DOEpatents

Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

Larsen, Robert P. (Downers Grove, IL)

1977-01-01

326

Physicochemical characterization of ten fractions of bovine alpha lipoproteins.  

PubMed

With the onset of milk production, serum concentrations of alpha lipoproteins in the dairy cow steadily increase, frequently attaining values greater than 1.5 g/dl. Since these lipoproteins comprise a highly polydisperse system, we have carried out studies to explore differences among bovine alpha lipoproteins in the density interval between 1.05 to 1.21 g/ml. Separation into ten fractions was achieved ultracentrifugally in an isopycnic gradient. Agarose gel electrophoresis showed that all but the bottom fraction contained alpha lipoproteins as either the major or sole lipoprotein class. Compositional analyses revealed an increasing percentage of both protein and phospholipid and a decreasing percentage of cholesterol with increasing fraction density. The esterified to unesterified cholesterol ratio ranged from 3 to 8 from the top to the bottom of the gradient. The densities of the particles obtained from the various fractions were calculated both from sedimentation velocity measurements and from compositional analyses. The resulting density values agreed well with the solution densities of these isopycnic gradient fractions. The major apoprotein of each fraction was apoA-I. Combining diffusion coefficient data obtained by intensity fluctuation spectroscopy with sedimentation velocity data, we were able to calculate molecular weights, frictional ratios, and Einstein-Stokes radii for three of the fractions. Results are discussed in terms of previously published data on bovine lipoproteins as well as other mammalian data. PMID:7077152

Puppione, D L; Kunitake, S T; Toomey, M L; Loh, E; Schumaker, V N

1982-03-01

327

[Radioprotective effect of alpha 2- adrenoreceptor agonists].  

PubMed

It is confirmed in experiments with selective antagonists, that radioprotective effects (RPE) of phenylephrine is realised by means of alpha 1--and RPE of clonidine--by means of alpha 2-adrenoceptors (AR). Guanobenz, more selective alpha 2-agonist with another structure, has high RPE too. Chemical analogues of clonidine (alpha-antagonist phentolamine, L-DOPA, DOP-serine), which don't cause selective stimulation of alpha 2-AR, don't protect mice. alpha 2-Agonists are new effective group of radioprotectors. PMID:7904881

Kulinski?, V I; Kovtun, V Iu; Klimova, A D; Iashunski?, V G

328

Order alpha^2 corrections to the decay rate of parapositronium  

Microsoft Academic Search

Parapositronium, the spin-0 electron-positron bound state, decays electromagnetically to an even number of photons. The theoretical expression for its decay rate has the form Gamma_p-Ps = Gamma0 Bigl [ 1 + A alpha \\\\over pi - 2 alpha^2 ln alpha + B Bigl ( alpha \\\\over pi Bigr )^2 - 3 alpha^3 \\\\over 2 pi ln^2 alpha + C alpha^3

Gregory Adkins; Richard Fell; Nathan McGovern; Jonathan Sapirstein

2003-01-01

329

Can fusion coefficients be calculated from the depth rule?  

NASA Astrophysics Data System (ADS)

The depth rule is a level truncation of tensor-product coefficients expected to be sufficient for the evaluation of fusion coefficients. We reformulate the depth rule in a precise way, and show how, in principle, it can be used to calculate fusion coefficients. However, we argue that the computation of the depth itself, in terms of which the constraints on tensor product coefficients is formulated, is problematic. Indeed, the elements of the basis of states convenient for calculating tensor product coefficients do not have a well-defined depth! We proceed by showing how one can calculate the depth in an ``approximate'' way and derive accurate lower bounds for the minimum level at which a coupling appears. It turns out that this method yields exact results for su(3) and constitutes an efficient and simple algorithm for computing su(3) fusion coefficients.

Kirillov, A. N.; Mathieu, P.; Sénéchal, D.; Walton, M. A.

1993-02-01

330

Renormalization of Buchdahl-Rimmer aberration coefficients to RMS expressions  

NASA Astrophysics Data System (ADS)

The Buchdahl-Rimmer aberration coefficients are commonly used in optical design programs for the evaluation of third- and fifth-order aberrations. The information given by these coefficients is difficult to interpret since there is no direct relationship between the numerical value of the coefficient and its effect on the image quality, i.e. the most important aberration is not necessarily the one with the largest numerical value. To look at the effect that each aberration has on the image quality it is necessary to re-normalize the Buchdahl-Rimmer coefficients. The purpose of this work is to re-normalize the Buchdahl-Rimmer coefficients of the wave aberration function in terms of the strehl intensity ratio as well as to re-normalize the Buchdahl-Rimmer coefficients of the geometric aberration function in terms of the RMS spot size.

Rosete-Aguilar, Martha; Rayces, Juan L.

1996-02-01

331

Correlation coefficients in ecologic studies of environment and cancer.  

PubMed

The objective of this study was to determine the proportion of ecologic studies published during a 20-year period regarding environmental exposures and cancer in which correlation coefficients or coefficients of determination were used as a measure of association. The authors performed a descriptive analysis of published literature by conducting a systematic review of PubMed to identify eligible ecologic studies published between 1991 and 2010. The reported measure of association was extracted for all eligible studies. During the 20-year study period, 35/105 (33%, 95% confidence limits [CL]: 25%, 43%) ecologic studies used correlation coefficients or coefficients of determination as a measure of association. These results indicate that the use of correlation coefficients and coefficients of determination as measures of association in ecologic studies of environmental exposures and cancer is relatively common, despite extensive literature discouraging their interpretation as valid measures of association. PMID:22014198

Ojha, Rohit P; Offutt-Powell, Tabatha N; Evans, Eva L; Singh, Karan P

2011-01-01

332

Alpha Testing Escape from Diab  

Technology Transfer Automated Retrieval System (TEKTRAN)

Alpha testing was conducted of sessions 2 and 3 from Diab to assess whether the activities worked as expected, and whether children in the target ages enjoyed it. Data include both RA observations of child performance while playing the games and cognitive interview responses from the players after t...

333

Alpha Sources Deposit by Sublimation.  

National Technical Information Service (NTIS)

We studied and realized a device able to perform some very thin deposition used for alpha spectrometry measurements. Sources are prepared by sublimation of the sample in a vacuum container. The energy required for this sublimation is furnished by a laser ...

F. Amoudry J. F. Eloy

1983-01-01

334

Alpha Proton X ray Spectrometer.  

National Technical Information Service (NTIS)

Mars Pathfinder will carry an alpha-proton x ray spectrometer (APX) for the determination of the elemental chemical composition of Martian rocks and soils. The instrument will measure the concentration of all major and some minor elements, including C, N,...

R. Rieder H. Waeke T. Economou

1994-01-01

335

Alcoholism, Alpha Production, and Biofeedback  

ERIC Educational Resources Information Center

|Electroencephalograms of 20 alcoholics and 20 nonalcoholics were obtained. Data indicated that alcoholics produced less alpha than nonalcoholics. In one training condition subjects were given accurate biofeedback, whereas in the other condition subjects were given random (noncontingent) feedback. Accurate biofeedback did not result in greater…

Jones, Frances W.; Holmes, David S.

1976-01-01

336

ISS Update: Alpha Magnetic Spectrometer  

NASA Video Gallery

NASA Public Affairs Officer Kelly Humphries interviews Trent Martin, Johnson Space Center project manager for the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. Questions? Ask us on Twitter @NASA_Johnson and include the hashtag #askStation. For the latest news about the space station, visit http://www.nasa.gov/station.

Gerald T Wright

2012-02-24

337

Alpha proton x ray spectrometer  

NASA Astrophysics Data System (ADS)

Mars Pathfinder will carry an alpha-proton x ray spectrometer (APX) for the determination of the elemental chemical composition of Martian rocks and soils. The instrument will measure the concentration of all major and some minor elements, including C, N, and O at levels above typically 1 percent.

Rieder, Rudi; Waeke, H.; Economou, T.

338

Strategies on the evaluation of binomial coefficients for all integers  

NASA Astrophysics Data System (ADS)

Binomial coefficients are used in many fields such as computational and applied mathematics, statistics and probability, theoretical physics and chemistry. For accurate numerical results, the correct calculation of these coefficients is very important. We present some new recurrence relationships and numerical methods for the evaluation of binomial coefficients for negative integers. For this purpose, we give some comparisons of the outputs for different computer programming languages in case of negative integers, and also we wrote two new algorithms for computations.

Yükçü, Niyazi; Öztekin, Emin

2013-01-01

339

Multiscale object features from clustered complex wavelet coefficients  

Microsoft Academic Search

This paper introduces a method by which intuitive feature entities can be created from ILP (InterLevel Product) coefficients. The ILP transform is a pyramid of decimated complex-valued coefficients at multiple scales, derived from dual-tree complex wavelets, whose phases indicate the presence of different feature types (edges and ridges). We use an expectation-maximization algorithm to cluster large ILP coefficients that are

Ryan Anderson; Nick Kingsbury; Julien Fauqueur

2005-01-01

340

Image denoising algorithm based on the relevance of wavelet coefficients  

NASA Astrophysics Data System (ADS)

In this paper the wavelet transform and the wavelet transform theory have been elaborated. A wavelet coefficients' model in which individual shrinkage thresholds are selected for each coefficient has been established. The relationships between different wavelet coefficients are analyzed. According to this new model, a new algorithm of image denosing has been proposed. It is shown in the experiments that the new algorithm is more effective than traditional algorithms.

Ha, Yan

2009-11-01

341

Dispersion coefficients for interactions between helium atoms in Debye plasmas  

SciTech Connect

Effect of Debye plasmas on the dispersion coefficients C{sub 8}, C{sub 10}, and C{sub 12} for interactions between atoms has been investigated using highly accurate correlated exponential basis functions. In the free-atom case, the dispersion C{sub 12} coefficient and the hexadecapole polarizability for helium are reported. The dispersion coefficients, hexadecapole polarizability, and 1s5g {sup 1}G{sup e} state energy of helium for different screening parameters are also reported.

Kar, Sabyasachi [Center for Theoretical Atomic and Molecular Physics, The Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China); Ho, Y. K. [Institute of Atomic and Molecular Sciences, Academia Sinica, Post Office Box 23-166, Taipei, Taiwan 106 (China)

2010-06-15

342

Estimation of hydrodynamic coefficients for an AUV using nonlinear observers  

Microsoft Academic Search

Hydrodynamic coefficients strongly affect the dynamic performance of an autonomous underwater vehicle. Although these coefficients are generally obtained experimentally such as through the planar-motion-mechanism (PMM) test, the measured values are not completely reliable because of experimental difficulties and errors involved. Another approach by which these coefficients can be obtained is the observer method, in which a model-based estimation algorithm predicts

Joonyoung Kim; Kihun Kim; Hang S. Choi; Woojae Seong; Kyu-Yeul Lee

2002-01-01

343

Analytical scheme calculations of angular momentum coupling and recoupling coefficients  

NASA Astrophysics Data System (ADS)

We investigate the Scheme programming language opportunities to analytically calculate the Clebsch-Gordan coefficients, Wigner 6j and 9j symbols, and general recoupling coefficients that are used in the quantum theory of angular momentum. The considered coefficients are calculated by a direct evaluation of the sum formulas. The calculation results for large values of quantum angular momenta were compared with analogous calculations with FORTRAN and Java programming languages.

Deveikis, A.; Kuznecovas, A.

2007-03-01

344

Diffusion coefficients and conductivities of alkylimidazolium tetrafluoroborates and hexafluorophosphates  

Microsoft Academic Search

In this study, diffusion coefficients of alkylimidazolium tetrafluoroborates and hexafluorophosphates ionic liquids in water at room temperature were measured by the Taylor dispersion experiment. The Wilke–Chang equation underestimated the diffusion coefficient, but a modified Wilke–Chang equation correlated diffusion coefficients well with molar volumes. The conductivities of these ion liquids were also measured. Infinite dilute conductances were calculated. The Nernst–Haskell equation

Wen Cheng Su; Cheng Huang Chou; David Shan Hill Wong; Meng Hui Li

2007-01-01

345

DCFPAK: Dose coefficient data file package for Sandia National Laboratory  

SciTech Connect

The FORTRAN-based computer package DCFPAK (Dose Coefficient File Package) has been developed to provide electronic access to the dose coefficient data files summarized in Federal Guidance Reports 11 and 12. DCFPAK also provides access to standard information regarding decay chains and assembles dose coefficients for all dosimetrically significant radioactive progeny of a specified radionuclide. DCFPAK was designed for application on a PC but, with minor modifications, may be implemented on a UNIX workstation.

Eckerman, K.F.; Leggett, R.W.

1996-07-31

346

Microscopic formula for transport coefficients of causal hydrodynamics.  

PubMed

The Green-Kubo-Nakano formula should be modified in relativistic hydrodynamics because of the problem of acausality and the breaking of sum rules. In this Rapid Communication, we propose a formula to calculate the transport coefficients of causal hydrodynamics based on the projection operator method. As concrete examples, we derive the expressions for the diffusion coefficient, the shear viscosity coefficient, and corresponding relaxation times. PMID:17677204

Koide, T

2007-06-21

347

Microscopic formula for transport coefficients of causal hydrodynamics  

NASA Astrophysics Data System (ADS)

The Green-Kubo-Nakano formula should be modified in relativistic hydrodynamics because of the problem of acausality and the breaking of sum rules. In this Rapid Communication, we propose a formula to calculate the transport coefficients of causal hydrodynamics based on the projection operator method. As concrete examples, we derive the expressions for the diffusion coefficient, the shear viscosity coefficient, and corresponding relaxation times.

Koide, T.

2007-06-01

348

The relationship between elimination rates and partition coefficients  

Microsoft Academic Search

Rate constants for uptake and elimination of chemicals in organisms are often related to partition coefficients (typically the octanol–water partition coefficient). We show that the well-mixed one-compartment model for toxico-kinetics implies that the elimination rate is inversely proportional to the square root of the partition coefficient. When chemical exchange is limited by diffusion in the boundary layers adjacent to the

S. A. L. M. Kooijman; T. Jager; B. W. Kooi

2004-01-01

349

Determination and prediction of tissue-gas partition coefficients  

Microsoft Academic Search

The head space method for determination of tissue-gas partition coefficients was modified to make it suitable for determination of tissue-gas partition coefficients of water soluble solvents. The method was used to determine tissue-gas partition coefficients of acetone, 2-butanone, methanol, ethanol, 1-propanol, 2-propanol and isobutanol for six representative tissues (muscle, kidney, lung, white and gray matter of brain, and adipose tissue).

Vera Fiserova-Bergerova; Maria L. Diaz

1986-01-01

350

On the Connection Coefficients of the Chebyshev-Boubaker Polynomials  

PubMed Central

The Chebyshev-Boubaker polynomials are the orthogonal polynomials whose coefficient arrays are defined by ordinary Riordan arrays. Examples include the Chebyshev polynomials of the second kind and the Boubaker polynomials. We study the connection coefficients of this class of orthogonal polynomials, indicating how Riordan array techniques can lead to closed-form expressions for these connection coefficients as well as recurrence relations that define them.

2013-01-01

351

Friction coefficient measurement for autonomous winter road maintenance  

Microsoft Academic Search

Real-time measurement of tyre–road friction coefficient is extremely valuable for winter road maintenance operations, since knowledge of tyre–road friction coefficient can be used to optimise application of deicing chemicals to the roadway. In this paper, a wheel-based tyre–road friction coefficient measurement system is developed for snowploughs. Unlike a traditional Norse meter, this system is based on measurement of lateral tyre

Gurkan Erdogan; Lee Alexander; Rajesh Rajamani

2009-01-01

352

Alpha 1-adrenergic receptor structure  

SciTech Connect

The structure of the alpha 1-adrenergic receptor was investigated by comparing polypeptides identified by sodium dodecyl sulfate (NaDodSO4)-polyacrylamide gel electrophoresis with the size of the intact receptor in cell membranes as determined by target size analysis. The alpha 1-adrenergic receptor from rat liver membranes affinity-labeled with (/sup 3/H)phenoxybenzamine, a covalent affinity reagent, appeared as a single polypeptide with a molecular mass of 85,000 daltons (Da) on NaDodSO4-polyacrylamide gels. In the absence of protease inhibitors, smaller peptides of 58-62 kDa and 40-45 kDa, specifically labeled with (/sup 3/H)phenoxybenzamine, were also apparent on NaDodSO4 gels. In order to determine whether the 85-kDa protein represented all or only a portion of the alpha 1-receptor, radiation inactivation (target size analysis) was undertaken. Radiation-induced receptor inactivation was measured by the loss of specific (/sup 3/H)phenoxybenzamine and (/sup 3/H)prazosin binding and by the loss of affinity-labeled alpha 1-adrenergic receptors on NaDodSO4 gels. Target size analysis of rat liver alpha 1-receptors indicated that the intact membrane-bound receptor has an average molecular mass of 160,000 Da. These data suggest that the intact alpha-receptor may exist in the membrane as a dimer of two 85,000-Da subunits. The structure of the alpha 1-receptor was further studied by limited proteolysis of the 85-kDa protein isolated from NaDodSO4 gels. Trypsin, chymotrypsin, and papain produce smaller peptides similar to those produced during membrane isolation in the absence of protease inhibition. Limited proteolysis of the membrane-bound receptor produces water-soluble peptides, the largest of which is 45,000 Da. This peptide contains the ligand-binding domain and protrudes from the membrane into the extracellular space.

Venter, J.C.; Horne, P.; Eddy, B.; Greguski, R.; Fraser, C.M.

1984-09-01

353

The study of the reduced alpha-width and ANC of 16O states through its sequential breakup  

Microsoft Academic Search

In this work we theoretically study using continuum-discretized-coupled channel (CDCC) theory, the resonant breakup of 16O by comparison with a recent measurement. The ground state Asymptotic Normalization Coefficient (ANC) and the alpha spectroscopic factor of 16O are evaluated in this work. The peripheral aspect of resonance breakup through a 2+ unbound state has been also studied.

Sucheta Adhikari; Chinmay Basu

2009-01-01

354

Determination of the enantiomers of alpha-hydroxy- and alpha-amino acids in capillary electrophoresis with contactless conductivity detection.  

PubMed

The enantiomers of the anions of five alpha-hydroxy acids, namely lactic acid, alpha-hydroxybutyric acid, 2-hydroxycaproic acid, 2-hydroxyoctanoic acid and 2-hydroxydecanoic acid, as well as the two alpha-amino acids aspartic acid and glutamic acid, were baseline separated and detected by CE with contactless conductivity detection. Vancomycin was employed as chiral selector and could be used with conductivity detection without having to resort to a partial filling protocol as needed when this reagent is used with UV absorbance measurements. The procedure was successfully applied to the determination of the lactic acid enantiomers in samples of milk and yogurt. Linearity was achieved in the concentration range of 10-500 micromol/L with good correlation coefficients (0.9993 and 0.9990 for L- and D-lactic acid, respectively). The LODs (3 S/N) for L- and D-lactic acid were determined as 2.8 and 2.4 micromol/L, respectively. PMID:20496346

Pormsila, Worapan; Gong, Xiao Yang; Hauser, Peter C

2010-06-01

355

Modulation of gene expression by alpha-tocopherol and alpha-tocopheryl phosphate in thp-1 monocytes  

Technology Transfer Automated Retrieval System (TEKTRAN)

The naturally occurring vitamin E analogue, alpha-tocopheryl phosphate (alphaTP), has been reported to be more potent than the un-phosphorylated alpha alpha-tocopherol (alphaT). We have now measured plasma levels of alphaTP and compared the cellular effects of alphaTP and gamma-tocopheryl phosphate ...

356

Measurement of the extinction coefficients of magnetic fluids  

PubMed Central

A novel spectral transmittance approach for measuring the extinction coefficient of magnetic fluids is proposed. The measuring principle and accuracy of the approach are analysed. Experiments are conducted to measure the extinction coefficient of magnetic fluids with different particle volume fractions. The relative uncertainty of experimental data is less than 1.8%. The experimental results indicate that the extinction coefficient of magnetic fluids increases with increase of the volume fraction of suspended magnetic nanoparticles and the optical properties of the particle material have a significant effect on the extinction coefficient of the magnetic fluids.

2011-01-01

357

Determination of drag coefficients for a buoyant cable antenna  

NASA Astrophysics Data System (ADS)

Samples of buoyant cable antennas of various lengths and surface roughnesses were towed over a range of speeds and depths in different wave conditions. Based on measurements of the forces developed and using computerized prediction techniques, normal and tangential drag coefficients were determined for the submerged segment of the BCA configuration and drag coefficients were determined for the floating length segment. The drag coefficients are presented in both tabular and graphical form. The results indicate that both waves and surface roughness can have a significant effect on the drag coefficients. The results also indicate that the effects of cable stiffness on the accuracy of the cable catenary predictions require further investigation.

Israel, A. M.

1982-03-01

358

Methods of calculation of a friction coefficient: application to nanotubes.  

PubMed

In this Letter we develop theoretical and numerical methods to calculate the dynamic friction coefficient. The theoretical method is based on an adiabatic approximation which allows us to express the dynamic friction coefficient in terms of the time integral of the autocorrelation function of the force between both sliding objects. The motion of the objects and the autocorrelation function can be numerically calculated by molecular-dynamics simulations. We have successfully applied these methods to the evaluation of the dynamic friction coefficient of the relative motion of two concentric carbon nanotubes. The dynamic friction coefficient is shown to increase with the temperature. PMID:14611290

Servantie, J; Gaspard, P

2003-10-31

359

Giant Seebeck coefficient of the graphene/h-BN superlattices  

NASA Astrophysics Data System (ADS)

The electronic structures and Seebeck coefficients of the graphene/h-BN superlattices which consist of zigzag graphene nanoribbons (ZGNRs) and zigzag BN nanoribbons (ZBNNRs) have been investigated using ab initio calculations based on the density functional theory. It has been shown that a ZGNR/ZBNNR marks up to 20 times larger in the Seebeck coefficient than graphene. The Seebeck coefficients of the superlattices increase with decreasing width of the constituent ZGNR. It has been revealed that the giant Seebeck coefficients of the superlattices stem from the so-called pudding mold band with a finite energy gap.

Yokomizo, Yushi; Nakamura, Jun

2013-09-01

360

Rigorous bounds on Transmission, Reflection, and Bogoliubov coefficients  

NASA Astrophysics Data System (ADS)

This thesis describes the development of some basic mathematical tools of wide relevance to mathematical physics. Transmission and reflection coefficients are associated with quantum tunneling phenomena, while Bogoliubov coefficients are associated with the mathematically related problem of excitations of a parametric oscillator. While many approximation techniques for these quantities are known, very little is known about rigorous upper and lower bounds. In this thesis four separate problems relating to rigorous bounds on transmission, reflection and Bogoliubov coefficients are considered, divided into four separate themes: 1) Bounding the Bogoliubov coefficients; 2) Bounding the greybody factors for Schwarzschild black holes; 3) Transformation probabilities and the Miller--Good transformation; 4) Analytic bounds on transmission probabilities.

Boonserm, Petarpa

2009-06-01

361

Heat transfer coefficients for drying in pulsating flows  

SciTech Connect

Pulsating flows generated by a Rijke type combustor are studied for drying of grains and food particles. It is assumed that the velocity fluctuations are the main factor in the enhancement of the drying process. The heat transfer coefficients for drying in vibrating beds are utilized to estimate the heat transfer coefficients of fixed beds in pulsating and permeating flows and are compared to the steady flow heat transfer coefficients obtained for solid porous bodies, after perturbing the main flow. The cases considered are compared to the convective heat transfer coefficients employed in non-pulsating drying.

Fraenkel, S.L. [DEM/UFRJ, Rio de Janeiro (Brazil); Nogueira, L.A.H. [IEM/EFEI, Itajuba, Minas Gerais (Brazil); Carvalho, J.A. Jr.; Costa, F.S. [LCP/INPE, Cachoeira Paulista, Sao Paulo (Brazil)

1998-05-01

362

A synopsis of collective alpha effects and implications for ITER  

SciTech Connect

This paper discusses the following: Alpha Interaction with Toroidal Alfven Eigenmodes; Alpha Interaction with Ballooning Modes; Alpha Interaction with Fishbone Oscillations; and Implications for ITER.

Sigmar, D.J.

1990-10-01

363

Coincidence of EEG alpha Patterns in Humans.  

National Technical Information Service (NTIS)

The appearance of alpha patterns in one human may influence its appearance in another human. In selected instances, the coincidence of alpha patterns appear simultaneously in the EEG to a highly significant greater degree than would be expected by random ...

T. Behrendt T. D. Duane

1969-01-01

364

Embryonic Hemoglobins in alpha -Thalassemia Mice.  

National Technical Information Service (NTIS)

Embryonic hemoglobins in heterozygous alpha -thalassemic and normal fetuses were compared to study the effects of the deficient alpha chain on the synthesis of hemoglobins in the nucleated embryonic erythrocytes derived from the fetal yolk sac. Visual ins...

R. A. Popp B. S. Bradshaw G. P. Hirsch

1978-01-01

365

Radiolabeling of the interferon-alpha receptor  

SciTech Connect

The action of alpha interferon (IFN-alpha) is initiated by its binding to a specific cell-surface glycoprotein, the IFN-alpha receptor, which is not well characterized. IFN-alpha A was reacted with an /sup 125/I-labeled, cleavable, heterobifunctional reagent. The derivatized IFN-alpha A was bound to human Daudi cells and photoactivated, forming a covalent IFN/receptor complex of apparent molecular weight 130,000-140,000 by SDS-polyacrylamide gel electrophoresis. Cleavage of the complex produced a new /sup 125/I-labeled 110 kDa band, representing the /sup 125/I-labeled IFN-alpha receptor free of IFN-alpha. This result provides a better estimate of the apparent molecular weight of the IFN-alpha receptor, and also provides a tool for tracking the migration of the free receptor in SDS-polyacrylamide gel electrophoresis.

Langer, J.A.

1988-12-30

366

The Absorption of Incident Quanta by Atoms as Defined by the Mass Photoelectric Absorption Coefficient and the Mass Scattering Coefficient  

Microsoft Academic Search

Evidence presented indicates that the absorption of quanta as defined by the mass photoelectric absorption coefficient ??&rgr; and the mass scattering coefficient ??&rgr; of any element may be represented by a simple expression.Tabulated values of the calculated mass absorption coefficients ??&rgr; are given for wave-lengths from 0.01 to 40 angstroms for hydrogen and carbon and from 0.01 to ?K and

John A. Victoreen

1948-01-01

367

On a Variable-Coefficient Modified KP Equation and a Generalized Variable-Coefficient KP Equation with Computerized Symbolic Computation  

Microsoft Academic Search

The variable-coefficient nonlinear evolution equations, although realistically modeling various mechanical and physical situations, often cause some well-known powerful methods not to work efficiently. In this paper, we extend the power of the generalized hyperbolic-function method, which is based on the computerized symbolic computation, to a variable-coefficient modified Kadomtsov-Petviashvili (KP) equation and a generalized variable-coefficient KP equation. New exact analytic solutions

Yi-Tian Gao; Bo Tian

2001-01-01

368

On a Variable-Coefficient Modified KP Equation and a Generalized Variable-Coefficient KP Equation with Computerized Symbolic Computation  

NASA Astrophysics Data System (ADS)

The variable-coefficient nonlinear evolution equations, although realistically modeling various mechanical and physical situations, often cause some well-known powerful methods not to work efficiently. In this paper, we extend the power of the generalized hyperbolic-function method, which is based on the computerized symbolic computation, to a variable-coefficient modified Kadomtsov-Petviashvili (KP) equation and a generalized variable-coefficient KP equation. New exact analytic solutions thus come out.

Gao, Yi-Tian; Tian, Bo

369

Alpha-like calculations with MCNP  

SciTech Connect

Alpha (time-absorption eigenvalue) calculations are not an explicit calculational option in MCNP. Nevertheless, it is possible to perform alpha calculations with MCNP. Such calculations are presently either very inefficient or require special coding or cross section library modifications. However, alpha-like calculations can easily be performed with MCNP using the KCODE option with neutron energy- or time-cutoffs. These approximate alpha-like calculations are described and tested.

Parsons, D.K.

1997-11-01

370

Interaction of dihydromyricetin and alpha-amylase.  

PubMed

The interaction of dihydromyricetin (DMY) and alpha-amylase was investigated. The complex formed between DMY and alpha-amylase resulted in decreased antioxidant activity of DMY and the catalytic activity of the enzyme, as well as efficient quenching of the intrinsic fluorescence of alpha-amylase. An alpha-amylase molecule provides one binding site for a DMY molecule. These results will be useful for exploiting this compound to combat diseases efficiently. PMID:23678807

Chen, Lei; Wang, Chao; Wei, Qingyi; Ning, Zhengxiang; Yuan, Erdong

2013-03-01

371

Recent Results on the CKM Angle Alpha  

SciTech Connect

The method to measure the CKM angle {alpha} and the modes sensitive to it are discussed. It is shown that the B {yields} {rho}{rho} decays provide the most stringent constraint on {alpha}, which is found to be {alpha} = 96{sup o} {+-} 10{sup o}(stat) {+-} 4{sup o}(syst){+-} 13{sup o}(penguin).

Mihalyi, A.; /Wisconsin U., Madison

2005-10-18

372

Effectiveness of Alpha Biofeedback Therapy: Negative Results.  

ERIC Educational Resources Information Center

|Assessed the utility of alpha biofeedback training in the treatment of patients (N=66). Biofeedback and placebo biofeedback groups were given alpha or mock-alpha training sessions. Improvement on 54 variables was compared to that of no-treatment controls. Only a chance number of significant changes appeared among the groups. (Author)|

Watson, Charles G.; Herder, Joseph

1980-01-01

373

Atypical Alpha Asymmetry in Adults with ADHD  

ERIC Educational Resources Information Center

|Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha

Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

2009-01-01

374

Enrollment Management: Managing the Alpha AXP Program  

Microsoft Academic Search

The article describes an innovative program management methodology created at Digital Equipment Corporation during the development of the Alpha AXP program. Successful execution of the Alpha program was crucial to the company's future, but early projected schedules showed the product wouldn't be completed until a year after the competitive window closed. The author, who served as Alpha program manager, was

PETER F. CONKLIN

1996-01-01

375

SYNTHESIS OF ALDOSTERONE1\\/cap alpha\\/,2\\/cap alpha\\/-H³  

Microsoft Academic Search

The method of Osinki et al. was used to synthesize n analysis of ; peripheral blood. 1-Dehydroaldosterone 21-acetate in dioxane was reduced with ; tritium over 5% palladiumon-charcoal. Aldosterone acetate-1 alpha ,2 alpha -H\\/; sup 3\\/ was separated from the products by chromatography and hydrolyzed with ; lipase or bicarbonate to give aldosterone-1 alpha ,2 alpha -H³.(D.L.C.);

K. R. Laumas; M. Gut

1962-01-01

376

Magnetism of Alpha'-FeN Alloys and Alpha-(Fe16N2)Fe Nitrides.  

National Technical Information Service (NTIS)

The alpha'-FeN phase was prepared by treating Fe powder with NH3/H2 gas mixtures at a temperature of approx. 665 deg C followed by a quench to cryogenic temperatures. Conversion of alpha to alpha' to an extent exceeding 85% has been achieved. Alpha-FeN is...

M. Q. Huang W. E. Wallace S. Simizu S. G. Sankar

1994-01-01

377

Identification of Aerodynamic Coefficients of Ground Vehicles Using Neural Network  

Microsoft Academic Search

The purpose of this paper is to demonstrate the application of a combination of neural network and an oscillating model facility as an approach in identification of aerodynamic coefficients of ground vehicle. In literature study, a method for estimating transient aerodynamic data has been introduced and the aerodynamic coefficients are extracted from the measured time response by means of conventional

Nabilah Ramli; Shuhaimi Mansor; Hishamuddin Jamaluddin; Waleed Fekry Faris

2007-01-01

378

Resistance coefficient identification of ballistic with random wind  

Microsoft Academic Search

For the aerodynamic parameters identification of projectile and rocket under the influence of random wind, based on the control system sensitivity theory, the formation of the sensitivity and related mathematical models according to realistic systems are formulated. Sensitivity principle of the control system theory is applied to the identification of resistance coefficient. Analyzing missile system parameters, aerodynamic coefficients are identified

Xin Wang; Yuxin Wang; Jun Yao

2011-01-01

379

Coefficient identification of trajectory correction fuze based on sensitivity function  

Microsoft Academic Search

Trajectory correction fuze is the integrated guidance and control and the new fuze technology which can correct trajectory through the fuze. In order to improve solution precision for trajectory correction fuze, a resistance coefficient identification method based on the sensitivity theory of control system is put forward. Combined with test data of the ballistic parameters, resistance coefficient is identified in

Jian Zhang; Xin Wang; Jun Yao

2010-01-01

380

Loss coefficient correlation for wet-cooling tower fills  

Microsoft Academic Search

Loss coefficient correlations given in the literature for wet-cooling tower fills are relatively simple and generally do not represent the pressure drop accurately over a wide range of operational conditions. A new form of empirical equation is proposed that correlates fill loss coefficient data more effectively when compared to other forms of empirical equations commonly found in the literature.

Johannes C. Kloppers; Detlev G. Kröger

2003-01-01

381

In-situ determination of thermal coefficients for electrical machines  

Microsoft Academic Search

A method for determining the thermal coefficients in electrical machines based upon a new linear lumped parameter model and accurate measurement of temperature and loss densities within the machine is presented. The thermal network is reduced to a system of simultaneous equations. The equivalent thermal coefficients are determined by solving the equations using a singular value decomposition (SVD) method. Results

A. Bousbaine; M. McCormick; W. F. Low

1995-01-01

382

A Simple Geometric Approach to Approximating the Gini Coefficient  

ERIC Educational Resources Information Center

The author shows how a quick approximation of the Lorenz curve's Gini coefficient can be calculated empirically using numerical data presented in cumulative income quintiles. When the technique here was used to estimate 621 income quintile/Gini coefficient observations from the Deninger and Squire/World Bank data set, this approach performed…

Kasper, Hirschel; Golden, John

2008-01-01

383

Stability analysis of polynomials with coefficients in disks  

Microsoft Academic Search

The aim of this note is to report results on the stability of a class of polynomials from the small gain theorem point of view. The authors consider families of polynomials whose coefficients lie in closed circular disks around their nominal values. Various measures of variation of polynomial coefficients around their nominal value are considered and in each case necessary

Y. Li; K. M. Nagpal; E. B. Lee

1992-01-01

384

Activity coefficients of KCl in highly concentrated protein solutions  

Microsoft Academic Search

As a contribution to the understanding of the thermodynamic state of single salts in living systems, the activity coefficients of KCl were determined in concentrated bovine serum albumin (BSA) solutions. The concentration range studied was 0.01 to 0.5 M KCl and zero to 18% wt BSA, thus amply covering physiological conditions. The activity coefficients of the salt were measured using

P. Ocon; C. Acerete; M. D. Reboiras

1987-01-01

385

Coefficients for Tests from a Decision Theoretic Point of View  

Microsoft Academic Search

From a decision theoretic point of view a general coefficient for tests, d, is derived. The coefficient is applied to three kinds of decision situations. First, the situation is considered in which a true score is estimated by a function of the observed score of a subject on a test (point estimation). Using the squared error loss function and Kelley's

Wim J. van der Linden; Gideon J. Mellenbergh

1978-01-01

386

Drag Coefficient, Dynamic Roughness and Reference Wind Speed  

Microsoft Academic Search

Surface waves are the roughness element of the ocean surface. The parameterization of the drag coefficient of the ocean surface is simplified by referencing to wind speed at an elevation proportional to the characteristic wavelength. The dynamic roughness is analytically related to the drag coefficient. Under the assumption of fetch limited wave growth condition, various empirical functions of the dynamic

Paul A. Hwang

2005-01-01

387

Quenching of Einstein's A-coefficients by photons  

SciTech Connect

We present evidence for the quenching of Einstein A-coefficients in an Ar-ion laser discharge due to the presence of a high intensity laser flux. The reduction in spontaneous emission intensity when lasing occurs was found to be dependent on the Einstein A-coefficient for transitions originating from the same upper level. 9 refs., 3 figs.

Aumayr, F.; Hung, J.; Suckewer, S.

1989-05-01

388

Biases and Standard Errors of Standardized Regression Coefficients  

ERIC Educational Resources Information Center

|The paper obtains consistent standard errors (SE) and biases of order O(1/n) for the sample standardized regression coefficients with both random and given predictors. Analytical results indicate that the formulas for SEs given in popular text books are consistent only when the population value of the regression coefficient is zero. The sample…

Yuan, Ke-Hai; Chan, Wai

2011-01-01

389

A new descriptive statistic: The parabolic correlation coefficient  

Microsoft Academic Search

This article proposes a new descriptive statistic related to the second order parabola in the same manner in which the familiar correlation coefficient is related to the regression coefficient. The parabolicr describes in standard terms simultaneously the general trend of the regression and the extent and nature of its curvilinearity, and is relatively easy to compute and easy to communicate.

Charles C. Peters

1946-01-01

390

Estimating Regression Coefficients by Minimizing the Dispersion of the Residuals  

Microsoft Academic Search

An appealing approach to the problem of estimating the regression coefficients in a linear model is to find those values of the coefficients which make the residuals as small as possible. We give some measures of the dispersion of a set of numbers, and define our estimates as those values of the parameters which minimize the dispersion of the residuals.

Louis A. Jaeckel

1972-01-01

391

Evaluating convective heat transfer coefficients using neural networks  

Microsoft Academic Search

Liquid crystal thermography combined with transient conduction analysis is often used to deduce local values of convective heat transfer coefficients. Neural networks based on the backpropagation algorithm have been successfully applied to predict heat transfer coefficients from a given set of experimentally obtained conditions. Performance characteristics studied on numerous network configurations relevant to this application indicate that a 3-6-3-1 arrangement

K. Jambunathan; S. L. Hartle; S. Ashforth-Frost; V. N. Fontama

1996-01-01

392

A threat coefficient method for extended air defense system analysis  

Microsoft Academic Search

The extended air defense system has been analyzed. The Particular attention is paid to the threat of the air defense system to cruise missile. A method named Threat Coefficient Method was proposed based on the analysis of the air defense system structure and its operations. A threat coefficient model of the air defense system was built. It is shown that

Zhihong Yin; Naigang Cui; Shiyi Guan

2007-01-01

393

Mixture loss coefficient of safety valves used in nuclear plants  

Microsoft Academic Search

Theoretical and experimental investigations on the loss coefficient of gas–liquid mixture across safety relief valves have been carried out. Experiments were performed for three different types of safety valves and under different flow conditions. Using the Darcy equation and based on the presented experimental results, a new empirical correlation has been developed to calculate the loss coefficient and hence pressure

Shannak Benbella

2009-01-01

394

INFLUENCE COEFFICIENTS FOR RADIATION IN A CIRCULAR CYLINDER  

Microsoft Academic Search

A table of influence coefficients is calculated from which the ; distribution of absorbed radiation in a long circular cylinder having any ; distribution of emitted radiation can readily be determined. Lambert's law of ; diffuse emission and reflection is assumed, and the coefficient of absorptivity ; is supposed constant. A table of functions for the distribution of reflected ;

Parkes

1960-01-01

395

The Probability Plot Correlation Coefficient Test for Normality  

Microsoft Academic Search

This paper introdLlces the normal probability plot correlation coefficient as a test statistic in complete samples for the composite hypothesis of normality. The proposed test statistic is conceptnally simple, is compntationally convenient, and is readily extendible to testing non-normal distributional hypotheses. An empirical power strldy shows that the normal probability plot correlation coefficient, compares favorably with 7 other normal test

James J. Filliben

1975-01-01

396

Trace formulas for time delay and the second virial coefficient  

Microsoft Academic Search

A high-temperature expansion for the quantum-mechanical second virial coefficient is derived using newly developed trace formulas for time delay in scattering theory. The known cancellation between the bound state and continuum contributions is explained in this general framework. The method cam be extended to higher virial coefficients.

D. Bollé; H. Smeesters

1977-01-01

397

A Test for Diffusion Coefficient Measurement using Containerless Processing  

Microsoft Academic Search

Our purpose is the diffusion coefficient measurement using containerless processing to clarify the mass transfer mechanism in high temperature melts. Therefore, diffusion experiments as couples of molten Si-Ge and Al-Ag alloys have been performed using electromagnetic levitator combined with superconducting magnet. In this result, possibility of diffusion coefficient measurement in levitated melts applied static magnet field can be suggested, because

Kensuke Higuchi; Yuko Inatomi

398

Light-polymerized compomers: Coefficient of thermal expansion and microhardness  

Microsoft Academic Search

Statement of Problem. The relationship between the filler content, coefficient of thermal expansion, and microhardness of commercial light-polymerized compomers has not been fully investigated. Purpose. This study evaluated the effect of filler content on the coefficient of thermal expansion and microhardness of 3 commercially available light-polymerized compomers. Material and Methods. Five specimens each from 3 commercially available compomers (Compoglass F,

Yong Hoon Kwon; Tae-Yub Kwon; Joo L. Ong; Kyo-Ha Kim

2002-01-01

399

Determining the discharge coefficient of a spool valve  

Microsoft Academic Search

Various mathematical models and experimental methods have been developed for finding the effective orifice area in spool valves. The orifice equation for turbulent flow is often applied to spool valves to determine the volumetric flow rate of the fluid passing through the spool valve. This equation involves the discharge coefficient, Cd , in calculating the effective area. The discharge coefficient

E. N. Viall; Qin Zhang

2000-01-01

400

Constraining the Drag Coefficients of Meteors in Dark Flight.  

National Technical Information Service (NTIS)

Based on data in the aeronautics literature, we have derived functions for the drag coefficients of spheres and cubes as a function of Mach number. Experiments have shown that spheres and cubes exhibit an abrupt factor-of-two decrease in the drag coeffici...

M. E. Kress P. S. Jandir R. T. Carter

2011-01-01

401

Dihydro-alpha-lipoic acid has more potent cytotoxicity than alpha-lipoic acid  

Microsoft Academic Search

Alpha-lipoic acid has been shown to possess cancer-cell-killing activity via activation of the apoptosis pathway. In this\\u000a study, the cytotoxic activities of alpha-lipoic and dihydro-alpha-lipoic acid were compared in HL-60 cells. The cell-killing\\u000a activity of dihydro-alpha-lipoic acid was higher than that of alpha-lipoic acid. Both alpha-lipoic and dihydro-alpha-lipoic\\u000a acid induced caspase-3 cleavage and internucleosomal DNA fragmentation in treated cells. On

Masao Yamasaki; Akiko Kawabe; Kentaro Nishimoto; Harishkumar Madhyastha; Yoichi Sakakibara; Masahito Suiko; Takeaki Okamoto; Taiji Suda; Kenzo Uehira; Kazuo Nishiyama

2009-01-01

402

Is the Gini Coefficient a Stable Measure of Galaxy Structure?  

NASA Astrophysics Data System (ADS)

The Gini coefficient, a nonparametric measure of galaxy morphology, has recently taken up an important role in the automated identification of galaxy mergers. I present a critical assessment of its stability, based on a comparison of HST ACS imaging data from the GOODS and UDF surveys. Below a certain signal-to-noise level, the Gini coefficient depends strongly on the signal-to-noise ratio, and thus becomes useless for distinguishing different galaxy morphologies. Moreover, at all signal-to-noise levels the Gini coefficient shows a strong dependence on the choice of aperture within which it is measured. Consequently, quantitative selection criteria involving the Gini coefficient, such as a selection of merger candidates, cannot always be straightforwardly applied to different data sets. I discuss whether these effects could have affected previous studies that were based on the Gini coefficient, and establish signal-to-noise limits above which measured Gini values can be considered reliable.

Lisker, Thorsten

2008-12-01

403

Study on the extinction coefficient of spherical aerosol particles  

NASA Astrophysics Data System (ADS)

Based on Mie scattering theory, this paper introduces the basic principle of aerosol light scattering and the basic calculation method of the polarization characteristics of scattering light. The spherical aerosol model is widely applied for the convenient and simple theoretic calculation, using the scattering theory by introducing the scattering amplitude matrix to combine incident radiation with scattering light. In scattering theory, aerosol extinction parameter has very important role for improving the precision of the laser radar, remote sensing detection and so on. We have mainly discussed the relationship between the spherical particle radius and extinction coefficient, and relationship between refractive index of the particles and extinction coefficient, respectively. It is concluded that extinction coefficient as a function of particles' radius gradually oscillate approaching to 2 with the increasing of particle radius, and extinction coefficient curves as a function of refraction index have completely symmetric. The first major maximum of extinction coefficient also has obvious changes with different particles radius or refractive index.

Yang, Jian; Chen, He; Zhang, Yin-chao; Chen, Si-ying; Guo, Pan; Liu, Li-na

2013-09-01

404

Translation of dose coefficients From ICRP 53 to ICRP 80.  

PubMed

The effective dose coefficients tabulated in Publication 80 of the International Commission on Radiological Protection (ICRP) for the radiopharmaceuticals addressed earlier in ICRP Publication 53 are based on the tissue weighting factors of ICRP Publication 60. Presumably these values are derived from the tissue dose coefficients tabulated in Publication 53; however, no details regarding their derivation are provided. The tissue weighting factors of Publication 60 explicitly address tissue for which no dose coefficients were tabulated in Publication 53; for example, esophagus and a number of tissues comprising the remainder. In the absence of guidance, the authors have defined a set of rules for the translation and have undertaken an effort to derive the effective dose coefficients of Publication 80 starting with the organ/tissue dose coefficient of Publication 53. PMID:23274826

Moussa, Hanna M; Melanson, Mark A

2013-02-01

405

Rate coefficients for electron impact excitation of CO  

NASA Astrophysics Data System (ADS)

Rate coefficients for electron impact excitation of the CO molecule have been calculated both for equilibrium and non-equilibrium conditions in the presence of electric and magnetic fields. The rate coefficients have been determined for all relevant non-elastic processes: rotational excitation, vibrational excitation, electronic excitation into singlet and triplet states and particularly for ionization. In the case of non-equilibrium conditions, we had to determine electron energy distribution functions needed for rate coefficients calculations. The distribution functions were obtained by employing a Monte Carlo simulation developed in our laboratory. The simulations were performed for moderate values of electric field over gas number density ratios, E/N, from 0 to 1000 Td. Also, the rate coefficients have been determined in presence of magnetic field for typical values of magnetic field over gas number density ratios, B/N, from 500 to 3000 Hx. The results of equilibrium rate coefficients along with non-equilibrium ones have been shown.

Vojnovi?, M.; Popovi?, M.; Risti?, M. M.; Vi?i?, M. D.; Popari?, G. B.

2013-09-01

406

Equilibrium partition coefficients in iron-based alloys  

NASA Astrophysics Data System (ADS)

Accurate relationships between equilibrium partition coefficients and solute concentration are required for the prediction of solute redistribution during solidification. Thermodynamic analyses are presented to relate these coefficients to fundamental thermodynamic quantities. Using the most accurate data available, partition coefficients are calculated for ten Fe-X (X=Al, C, Cr, Mn, Ni, N, P, Si, S, Ti) binary systems and compared with literature values. Equations are presented to allow for prediction of these partition coefficients as a function of temperature, as well as liquidus temperature as a function of composition. In addition, partition coefficient values are examined for the ternary systems Fe-Cr-C, Fe-Mn-Ni, and Fe-Ni-S.

Battle, Thomas P.; Pehlke, Robert D.

1989-04-01

407

Taming the {alpha}-vacuum  

SciTech Connect

An interacting scalar field theory in de Sitter space appears to be nonrenormalizable for a generic {alpha}-vacuum state. This pathology arises since the usual propagator used allows for a constructive interference among propagators in loop corrections, which produces divergences that are not proportional to standard counterterms. This interference can be avoided by defining a new propagator for the {alpha}-vacuum based on a generalized time-ordering prescription. The generating functional associated with this propagator contains a source that couples to the field both at a point and at its antipode. To one loop order, we show that a set of theories with very general antipodal interactions is causal and renormalizable.

Collins, Hael; Holman, R. [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

2004-10-15

408

Reggeon calculus for alpha>1  

Microsoft Academic Search

We study the Reggeon calculus when Reggeons have alpha(0)>1 and vacuum quantum numbers. We sum all the Regge cuts in the weak-coupling regime where the p Reggeon couplings rp are small. The resulting amplitude saturates the Froissart bound, provided the triple-Regge coupling r3 is dominant. In impact-parameter space the amplitude is a uniform absorbing disk whose radius expands like lns.

J. B. Bronzan

1974-01-01

409

Radiation dose estimation and mass attenuation coefficients of cement samples used in Turkey.  

PubMed

Different cement samples commonly used in building construction in Turkey have been analyzed for natural radioactivity using gamma-ray spectrometry. The mean activity concentrations observed in the cement samples were 52, 40 and 324 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and world average limits. The radiological hazard parameters such as radium equivalent activities (Ra(eq)), gamma index (I(gamma)) and alpha index (I(alpha)) indices as well as terrestrial absorbed dose and annual effective dose rate were calculated and compared with the international data. The Ra(eq) values of cement are lower than the limit of 370 Bq kg(-1), equivalent to a gamma dose of 1.5 mSv y(-1). Moreover, the mass attenuation coefficients were determined experimentally and calculated theoretically using XCOM in some cement samples. Also, chemical compositions analyses of the cement samples were investigated. PMID:20018450

Damla, N; Cevik, U; Kobya, A I; Celik, A; Celik, N; Van Grieken, R

2009-12-16

410

X-ray analysis of alpha mercuric iodide crystal structure and processing effects  

SciTech Connect

X-ray topography and rocking curve experiments were performed on {alpha}-mercuric iodide samples. As-grown crystals were examined for Intrinsic defects and crystallinity. Orientation of certain defects depends on the direction of crystal growth. The propagation of as-grown crystalline features was documented. The extent of crystal damage Introduced during various steps of device fabrication such as sawing, polishing, etching and contact deposition was explored. Coefficients of linear thermal expansion of {alpha}{sub 33} = 54 {plus_minus} 5{center_dot}10{sup {minus}6}/{degrees}C along the tetragonal c-axis, [001] direction and {alpha}{sub 11} = 11 {plus_minus} 4{center_dot}10{sup {minus}6}/{degrees}C in the [100] direction were measured.

Keller, L. [CAMET Research, Inc., Goleta, CA (United States); Wang, E.X.; Cheng, A.Y. [EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations

1993-07-01

411

Alpha Channeling in Rotating Plasma with Stationary WavesIN.  

National Technical Information Service (NTIS)

An extension of the alpha channeling effect to supersonically rotating mirrors shows that the rotation itself can be driven using alpha particle energy. Alpha channeling uses radiofrequency waves to remove alpha particles collisionlessly at low energy. We...

A. Fetterman N. J. Fisch

2010-01-01

412

Noradrenergic alpha 1 and alpha 2 Receptors: Light Microscopic Autoradiographic Localization  

Microsoft Academic Search

[3H]WB-4101 and p-[3H]aminoclonidine were used for light microscopic autoradiographic localization of alpha 1 and alpha 2 adrenergic receptors, respectively, in the rat brain. The binding of these ligands to slide-mounted tissue sections had all of the characteristics associated with alpha 1 and alpha 2 receptors. It was saturable with appropriate kinetic constants and was blocked only by other alpha -adrenergic

W. Scott Young; Michael J. Kuhar

1980-01-01

413

alpha(1)-, alpha(2)- and beta-adrenoceptors in the urinary bladder, urethra and prostate  

Microsoft Academic Search

1 We have systematically reviewed the presence, functional responses and regulation of alpha(1)-, alpha(2)- and beta-adrenoceptors in the bladder, urethra and prostate, with special emphasis on human tissues and receptor subtypes. 2 alpha(1)-Adrenoceptors are only poorly expressed and play a limited functional role in the detrusor. alpha(1)-Adrenoceptors, particularly their alpha(1A)-Subtype, show a more pronounced expression and promote contraction of the

M. C. Michel; W. Vrydag

2006-01-01

414

Intercomparisons of Experimental Convective Heat Transfer Coefficients and Mass Transfer Coefficients of Urban Surfaces  

NASA Astrophysics Data System (ADS)

The convective heat transfer coefficient (CHTC) of an urban canopy is a crucial parameter for estimating the turbulent heat flux in an urban area. We compared recent experimental research on the CHTC and the mass transfer coefficient (MTC) of urban surfaces in the field and in wind tunnels. Our findings are summarised as follows. (1) In full-scale measurements on horizontal building roofs, the CHTC is sensitive to the height of the reference wind speed for heights below 1.5 m but is relatively independent of roof size. (2) In full-scale measurements of vertical building walls, the dependence of the CHTC on wind speed is significantly influenced by the choice of the measurement position and wall size. The CHTC of the edge of the building wall is much higher than that near the centre. (3) In spite of differences of the measurement methods, wind-tunnel experiments of the MTC give similar relations between the ratio of street width to canopy height in the urban canopy. Moreover, this relationship is consistent with known properties of the flow regime of an urban canopy. (4) Full-scale measurements on roofs result in a non-dimensional CHTC several tens of times greater than that in scale-model experiments with the same Reynolds number.

Although there is some agreement in the measured values, our overall understanding of the CHTC remains too low for accurate modelling of urban climate.

Hagishima, Aya; Tanimoto, Jun; Narita, Ken-Ich

2005-12-01

415

Alpha Channeling in Centrifugal Mirror Machines  

NASA Astrophysics Data System (ADS)

The wave-particle alpha-channeling effect is generalized to include rotating plasma. Specifically, radio frequency waves can resonate with alpha particles in a mirror machine with ExB rotation to diffuse the alpha particles along constrained paths in phase space. Of major interest is that the alpha particle energy, in addition to amplifying the RF waves, can directly enhance the rotation energy which provides plasma confinement. This is an immediate and important technological use of this energy in that it reduces the dependency on electrodes contacting the plasma to provide the voltage profile. An ancillary benefit is the rapid removal of alpha particles, which increases the fusion reactivity.

Fetterman, Abraham; Fisch, Nathaniel

2008-11-01

416

Alpha channeling in a rotating plasma.  

PubMed

The wave-particle alpha-channeling effect is generalized to include rotating plasma. Specifically, radio frequency waves can resonate with alpha particles in a mirror machine with ExB rotation to diffuse the alpha particles along constrained paths in phase space. Of major interest is that the alpha-particle energy, in addition to amplifying the rf waves, can directly enhance the rotation energy which in turn provides additional plasma confinement in centrifugal fusion reactors. An ancillary benefit is the rapid removal of alpha particles, which increases the fusion reactivity. PMID:19113347

Fetterman, Abraham J; Fisch, Nathaniel J

2008-11-13

417

Efficient synthesis of symmetrical alpha,alpha-disubstituted beta-amino acids and alpha,alpha-disubstituted aldehydes via dialkylation of nucleophilic beta-alanine equivalent.  

PubMed

Homologation of the nucleophilic beta-alanine equivalent beta-Ala Ni(II)-PABP [Ni(II) complex of beta-alanine Schiff base with 2-[N-(alpha-picolyl)amino]benzophenone (PABP), 1] via alkyl halide alkylation was systematically studied as a general method for preparing symmetrically alpha,alpha-disubstituted beta-amino acids. The dialkylation reactions could be easily performed and did not require inert atmosphere, dried solvents, and low temperatures, thereby affording the benefits of operationally convenient experimental procedure and high atom economy. Further, the methodology developed by us can also be used to generate symmetrical alpha,alpha-disubstituted aldehydes through an alternative decomposition method. PMID:20141112

Lin, Daizong; Deng, Guanghui; Wang, Jiang; Ding, Xiao; Jiang, Hualiang; Liu, Hong

2010-03-01

418

{alpha} Channeling in a Rotating Plasma  

SciTech Connect

The wave-particle {alpha}-channeling effect is generalized to include rotating plasma. Specifically, radio frequency waves can resonate with {alpha} particles in a mirror machine with ExB rotation to diffuse the {alpha} particles along constrained paths in phase space. Of major interest is that the {alpha}-particle energy, in addition to amplifying the rf waves, can directly enhance the rotation energy which in turn provides additional plasma confinement in centrifugal fusion reactors. An ancillary benefit is the rapid removal of alpha particles, which increases the fusion reactivity.

Fetterman, Abraham J.; Fisch, Nathaniel J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States)

2008-11-14

419

Heat loss coefficients and effective tau-alpha products for flat-plate collectors with diathermanous covers  

NASA Astrophysics Data System (ADS)

This paper presents an efficient algorithm for solving the set of nonlinear equations governing the total heat transfer across an arbitrary number of parallel flat plate solar collector covers, each of which can be partly transparent to longwave thermal radiation. The governing equations are sufficiently general to permit each cover to have asymmetric radiative properties and to account for absorption of solar energy on the individual covers. This theory is shown to be in good agreement with the approximate equations of Whillier (provided certain interpretations are placed on his quantities) and with experiments using a plastic inner cover and bounding plates of various emissivities. Using this theory, it is demonstrated that if the absorber plate has a selective surface, an inner cover transparent to long wave radiation is to be preferred over one which is opaque.

Hollands, K. G. T.; Wright, J. L.

420

Further discussion of the octanol/air partition coefficient Koa as a correlating parameter for gas/particle partitioning coefficients  

NASA Astrophysics Data System (ADS)

The pure-compound liquid vapor pressure ( poL) has been used extensively as a log-log correlating parameter for gas/particle partitioning constants. When the partitioning to the aerosol particle phase involves partitioning into an organic material (om) phase, the success of poL in this context relies on compound-to-compound constancy of the molecular activity coefficient ?om in the om phase. While ?om for a particular type of aerosol may indeed tend to remain constant within a given compound class, significant class-to-class variations in ?om are certain. This paper discusses the theory underlying the advantages of using the octanol/air partition coefficient Koa as a correlating parameter for gas/particle partitioning constants. In particular, it is far more likely that different compounds will exhibit similar values of the ratio ? oct/? om than it is that they will exhibit similar values of ?om. The conclusion that the octanol-based partition coefficient Koa has significant advantages over the pure-compound partition coefficient poL when parameterizing gas/particle partitioning has a direct analog in the selection of the octanol/water partition coefficient Kow as a correlating parameter for soil/water partition coefficients like the organic carbon/water partition coefficient Koc. The nature of this analogy is discussed in detail. The acknowledged success of log K ow in this regard presages wide application of log K oa as a correlating parameter for gas/particle partition coefficients.

Pankow, James F.

421

Prediction of 1-octanol–water partition coefficient and infinite dilution activity coefficient in water from the PR + COSMOSAC model  

Microsoft Academic Search

The Peng–Robinson equation of state (PR EOS) is used for the prediction of 1-octanol–water partition coefficients (KOW) and infinite dilution activity coefficients (??). Unlike the conventional approach where the EOS parameters must be determined from the critical properties and acentric factor of each chemical species in addition to using some mixing rule to account for composition dependence, these parameters are

Chieh-Ming Hsieh; Shiang-Tai Lin

2009-01-01

422

PPAR-alpha in cutaneous inflammation  

PubMed Central

Peroxisome proliferator-activated receptor (PPAR)-alpha is a fatty acid activated transcription factors that belongs to the nuclear hormone receptor family. Primarily PPAR-alpha serves as a lipid sensor. While PPAR-alpha controls enzymes from the lipid and glucose metabolism in the liver, heart and muscles, PPAR-alpha is also involved in skin homeostasis. PPAR-alpha controls keratinocyte proliferation/differentiation, contributes to wound healing and regulates skin inflammation. PPAR-alpha activation exerts anti-inflammatory effects in various skin conditions such as irritant and allergic contact dermatitis, atopic dermatitis and UV-induced erythema, rendering investigations into the functions of PPAR-alpha necessary to provide better understandings to treat many inflammatory skin disorders.

Schmuth, Matthias

2011-01-01

423

MIP-1 alpha and myeloma bone disease.  

PubMed

Figure 5 is a proposed model for MIP-1alpha's effects on myeloma bone disease. MIP-1alpha is produced by myeloma cells and directly stimulates OCL formation. In addition MIP-1alpha enhances adhesive interactions between myeloma cells and marrow stromal cells increasing expression of RANKL and IL-6, which further increase bone destruction and tumor burden. The recent evidence from our group and others lead to the conclusion that MIP-1alpha is an important mediator in the debilitating bone destruction in multiple myeloma. Blocking MIP-1alpha expression may have profound effects on myeloma cell growth, homing, and bone destruction in this in vivo model of myeloma. These data suggest that antagonists that decrease MIP-1alpha activity in vivo or blocking MIP-1alpha signaling by neutralizing its receptor may provide therapeutic alternatives for treating patients with myeloma to decrease both their tumor burden and bone destruction. PMID:15043189

Roodman, G David; Choi, Sun Jin

2004-01-01

424

Growing of Si{x}Ge{{1}scriptsize-x}O{2} single crystals with alpha-quartz structure and their characterization  

Microsoft Academic Search

Crystals of alpha -SixGe{1scriptsize-x}O{2} solid solution is a new material with relatively high piezoelectric coefficients and temperature stability. Theoretical and experimental study on the development of reliable and reproducible method of alpha -SixGe{1scriptsize-x}O{2} crystal growth under hydrothermal conditions will be proposed in the report. Influence of the composition of solutions, T-P parameters, growth rates of different faces, capture and distribution

V. S. Balitsky; D. V. Balitsky; A. N. Nekrasov; L. V. Balitskaya

2005-01-01

425

Osmotic fragility test in heterozygotes for alpha and beta thalassaemia  

Microsoft Academic Search

This study shows that the combination of heterozygous beta thalassaemia and deletion heterozygous (-alpha\\/alpha alpha) or homozygous (-alpha\\/-alpha) alpha+ thalassaemia may result in the production of erythrocytes which have normal mean volume and haemoglobinisation but decreased osmotic fragility. Based on this finding and previous studies, which have shown that beta thalassaemia screening by the osmotic fragility test may miss a

L Maccioni; A Cao

1985-01-01

426

alpha-Tocopheryl phosphate – an active lipid mediator?  

Technology Transfer Automated Retrieval System (TEKTRAN)

The vitamin E (alpha-tocopherol, alphaT) derivative, alpha-tocopheryl phosphate (alphaTP), is detectable in small amounts in plasma, tissues, and cultured cells. Studies done in vitro and in vivo suggest that alphaT can become phosphorylated and alphaTP dephosphorylated, suggesting the existence of ...

427

Drag and energy accommodation coefficients during sunspot maximum  

NASA Astrophysics Data System (ADS)

Conditions appropriate to gas-surface interactions on satellite surfaces in orbit have not been successfully duplicated in the laboratory. However, measurements by pressure gauges and mass spectrometers in orbit have revealed enough of the basic physical chemistry that realistic theoretical models of the gas-surface interaction can now be used to calculate physical drag coefficients. The dependence of these drag coefficients on conditions in space can be inferred by comparing the physical drag coefficient of a satellite with a drag coefficient fitted to its observed orbital decay. This study takes advantage of recent data on spheres and attitude stabilized satellites to compare physical drag coefficients with the histories of the orbital decay of several satellites during the recent sunspot maximum. The orbital decay was obtained by fitting, in a least squares sense, the semi-major axis decay inferred from the historical two-line elements acquired by the US Space Surveillance Network. All the principal orbital perturbations were included, namely geopotential harmonics up to the 16th degree and order, third body attraction of the Moon and the Sun, direct solar radiation pressure (with eclipses), and aerodynamic drag, using the Jacchia-Bowman 2006 (JB2006) model to describe the atmospheric density. After adjusting for density model bias, a comparison of the fitted drag coefficient with the physical drag coefficient has yielded values for the energy accommodation coefficient as well as for the physical drag coefficient as a function of altitude during solar maximum conditions. The results are consistent with the altitude and solar cycle variation of atomic oxygen, which is known to be adsorbed on satellite surfaces, affecting both the energy accommodation and angular distribution of the reemitted molecules.

Pardini, C.; Anselmo, L.; Moe, K.; Moe, M. M.

2010-03-01

428

Universal statistics of the scattering coefficient of chaotic microwave cavities  

SciTech Connect

We consider the statistics of the scattering coefficient S of a chaotic microwave cavity coupled to a single port. We remove the nonuniversal effects of the coupling from the experimental S data using the radiation impedance obtained directly from the experiments. We thus obtain the normalized scattering coefficient whose probability density function (PDF) is predicted to be universal in that it depends only on the loss (quality factor) of the cavity. We compare experimental PDFs of the normalized scattering coefficients with those obtained from random matrix theory (RMT), and find excellent agreement. The results apply to scattering measurements on any wave chaotic system.

Hemmady, Sameer [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Center for Superconductivity Research, University of Maryland, College Park, Maryland 20742 (United States); Zheng, Xing [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Antonsen, Thomas M. Jr.; Ott, Edward [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Anlage, Steven M. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States); Center for Superconductivity Research, University of Maryland, College Park, Maryland 20742 (United States)

2005-05-01

429

Correlation of octanol/water solubility ratios and partition coefficients  

SciTech Connect

The partition coefficient between octanol and water in an important physicochemical parameter for characterizing the lipophilicity or hydrophobicity of a compound and it is used in many fields, especially in the environmental and pharmaceutical sciences. The octanol/water solubility ratio (S{sub o}/S{sub W}) was found to be highly correlated with the octanol/water partition coefficient (K{sub ow}) of 82 pharmaceutically and environmentally relevant compounds. The solubility ratio gives comparable estimates to that of the group contribution (log P(calcd)) method for estimating the partition coefficient of the compounds used in this study.

Pinsuwan, S.; Li, A.; Yalkowsky, S.H. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Pharmaceutical Sciences

1995-05-01

430

[Measurement of thermal expansion coefficient of human teeth].  

PubMed

The coefficient of thermal expansion of specimens from 60 freshly extracted sound human teeth was measured by a dilatometer over the range 10-80 degrees C. The coefficient increased rapidly above 50 degrees C, but there was no significant variation with the tooth age between 10 and 70 years. At 10-50 degrees C, the coefficient of thermal expansion was almost constant. The human teeth are usually at this temperature range in oral cavity. The authors suggest that the average values obtained can be used as quotable values. PMID:2128231

Xu, H C

1990-07-01

431

Gamma-ray attenuation coefficients in bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Mass attenuation coefficients of glasses in the system: xBi2O3(1-x)B2O3 (x=0.30, 0.35, 0.40, 0.45 and 0.55) were determined at 356, 662, 1173 and 1332 keV photon energies using a narrow beam transmission method. Appreciable variations were observed in these coefficients due to changes in the chemical composition of glasses. These coefficients were then used to determine effective atomic numbers of glass samples, which were found to be constant with bismuth concentration and energy.

Singh, Kulwant; Singh, Harvinder; Sharma, Vishal; Nathuram, Rohila; Khanna, Atul; Kumar, Rajesh; Singh Bhatti, Surjit; Singh Sahota, Hari

2002-07-01

432

The pressure coefficient of the Curie temperature of ferromagnetic superconductors  

NASA Astrophysics Data System (ADS)

The pressure coefficient of the Curie temperature of ferromagnetic superconductors is studied numerically. In our previous study the pressure coefficient of the Curie temperature and that of the superconducting transition temperature were shown based on the Hamiltonian derived by Linder et al. within the mean field approximation about the electron-electron interaction analytically. There have been no numerical results of the pressure coefficient of the Curie temperature derived from the microscopic model. In this study the numerical results are reported. These results are qualitatively consistent with the experimental data in UGe2.

Konno, R.; Hatayama, N.

2012-12-01

433

Vibrationally averaged isotropic dispersion energy coefficients of the parahydrogen dimer  

NASA Astrophysics Data System (ADS)

We compare the sum-over-states and coupled cluster linear response formalisms for the determination of imaginary-frequency polarizabilities of H2. Using both approaches, we compute isotropic dispersion energy coefficients Cn (n = 6, 8, 10) for H2-H2 molecular pairs over a wide range of H2 bond lengths. We present vibrationally averaged dispersion energy coefficients for H2-H2, H2-D2, and D2-D2 molecular pairs and examine the coefficients' convergence with respect to basis set.

Lillestolen, Timothy C.; Hinde, Robert J.

2012-05-01

434

The deposition coefficient and its role for cirrus clouds  

NASA Astrophysics Data System (ADS)

The potential of homogeneous freezing nucleation to produce large numbers of ice crystals in regions of gentle updraft has been underestimated so far. Small but realistic deposition coefficients for small ice crystals lead to longer periods with relative humidity staying near the critical value for nucleation, which results in much larger numbers of ice crystals than with deposition coefficients close to unity. This mechanism allows to reproduce number densities of crystals in the 10-30 ?m size range obtained from recent measurement campaigns. Potential reasons for small deposition coefficients are discussed, and new laboratory experiments to measure them are recommended.

Gierens, Klaus M.; Monier, Marie; Gayet, Jean-Francois

2003-01-01

435

Measurement of the diffusion coefficient for chrysotile and crocidolite fibers  

NASA Astrophysics Data System (ADS)

Diffusion coefficients for chrysolite and crocidolite fibers were measured with a Sinclair collimated hole diffusion battery and a condensation nuclei counter. The diffusion coefficient for the chrysotile fibers was found to be ~ 4-5 × 10 -7cm 2s -1 and was independent of the frequency of the generator. The crocidolite fibers were 6 × 10 -7cm 2s -1 and show somewhat more scatter. Comparison of the measured diffusion coefficients with calculated values from scanning electron micrographs indicated good agreement for the crocidolite fibers; but that experimental values were twice that of the calculated values for chrysotile.

Gentry, J. W.; Spurny, K. R.; Schormann, J.; Opiela, H.; Weiss, G.

436

Inertial likelihood maximization for reaction coordinates with high transmission coefficients  

NASA Astrophysics Data System (ADS)

For bilinearly coupled oscillator models, we examine the statistical relationship between transmission coefficients and committor distribution variances for reaction coordinates obtained by likelihood maximization. Transmission coefficients usually but not always increase as committor distributions narrow for the original version of likelihood maximization. We propose a new inertial version of likelihood maximization that uses velocity information to optimize purely configuration dependent coordinates. The coordinates from inertial likelihood maximization have higher transmission coefficients than coordinates from the original likelihood maximization procedure. Inertial likelihood maximization should be useful for understanding mechanisms of inertial reactions from atomistic simulations.

Peters, Baron

2012-12-01

437

Prediction of Protein-protein Interactions Using Alpha Shape Modeling  

NASA Astrophysics Data System (ADS)

Protein-protein interactions play important roles in a lot of biological progress. Previous studies about protein-protein interactions were mainly based on sequence analysis. As more 3D structural information can be obtained from protein-protein complexes, structural analysis becomes feasible and useful. In this study, we used structural alignment to predict the protein-binding site and apply 3D alpha shape modeling to analyze the interface characteristics. We have developed a method for protein-protein interaction prediction. The result indicates good performance of our method in discriminating protein-binding structures from non-protein binding structures. Our method outperforms the previous methods based on the Matthews correlation coefficient.

Zhou, Weiqiang; Yan, Hong; Fan, Xiaodan; Hao, Quan

2011-06-01

438

Mathematical model of an air-filled alpha stirling refrigerator  

NASA Astrophysics Data System (ADS)

This work develops a mathematical model for an alpha Stirling refrigerator with air as the working fluid and will be useful in optimizing the mechanical design of these machines. Two pistons cyclically compress and expand air while moving sinusoidally in separate chambers connected by a regenerator, thus creating a temperature difference across the system. A complete non-linear mathematical model of the machine, including air thermodynamics, and heat transfer from the walls, as well as heat transfer and fluid resistance in the regenerator, is developed. Non-dimensional groups are derived, and the mathematical model is numerically solved. The heat transfer and work are found for both chambers, and the coefficient of performance of each chamber is calculated. Important design parameters are varied and their effect on refrigerator performance determined. This sensitivity analysis, which shows what the significant parameters are, is a useful tool for the design of practical Stirling refrigeration systems.

McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir

2013-10-01

439

Atypical alpha asymmetry in adults with ADHD*  

PubMed Central

Introduction A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8– 12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha asymmetry has been associated with ADHD-like traits such as reduced reward responsiveness, a lack of inhibition toward aversive experience, and increased approach behaviors, and previous work has indicated increased rightward alpha asymmetry in children with ADHD. The current study explores whether increased rightward alpha asymmetry is also evident in adults with ADHD. Method We assessed low (8– 10 Hz) and high (10– 12 Hz) alpha asymmetry in adults with ADHD (n = 29) versus controls (n = 62) during baseline and cognitive activation conditions for nine homologous electrode pairs along the anterior–posterior axis. Result Seven results emerged (p < .05) showing increased rightward alpha asymmetry in adults with ADHD. This occurred in three specific electrode pairs across two testing conditions, and five of six results occurred in the lower alpha band. Finally, post hoc analysis indicated that increased rightward alpha asymmetry was generally associated with greater numbers of ADHD symptoms—with a possible parietal association for inattentive and a fronto-temporal association for hyperactivity symptoms. Conclusions Increased rightward alpha asymmetry previously observed in children with ADHD appears to be a developmentally persistent feature of ADHD.

Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

2009-01-01

440

Alpha-thalassemia in Papua New Guinea.  

PubMed

A study of the distribution of alpha-thalassemia in Papua New Guinea (PNG) was carried out by DNA analysis. A total of 664 DNA samples were screened for alpha-thalassemia 2 and alpha-thalassemia 1 caused respectively by either deletion of one or both of the duplicated alpha-globin genes. alpha-Thalassemia 2 was detected in high frequencies in coastal and lowland regions where malaria has been holo- to hyperendemic but in low frequencies in non-malarious highland regions. The highest frequency was observed in the north coast of PNG. The distribution of alpha-thalassemia 2 seems to be in accordance with other conditions such as ovalocytosis and G6PD deficiency which are also prevalent in this population, suggesting that they may interact in protection against malaria. However, it appears to be negatively correlated with beta-thalassemia and alpha-thalassemia 1, the latter being extremely rare in this population. Analysis of the types and subtypes of the single alpha-globin gene deletion revealed a predominance of the -alpha 4.2 type in general, except in some regions in the south where the -alpha 3.7 type is prevalent. The -alpha 3.7 I subtype is the common form of the -alpha 3.7 deletion in the PNG mainland. The -alpha 3.7 III subtype, previously reported to be unique in Melanesians and Polynesians, was detected in an offshore island of PNG. However, this subtype is very rare in Melanesians from the PNG mainland. PMID:2878871

Yenchitsomanus, P; Summers, K M; Board, P G; Bhatia, K K; Jones, G L; Johnston, K; Nurse, G T

1986-12-01

441

Synthesis of 3 alpha, 7 alpha-dihydroxy-5 beta-cholestan-26-oic acid from 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid: configuration in the bile of Alligator mississippiensis.  

PubMed

Synthesis of 25R- and 25S-diastereoisomers of 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid from 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid is described. The 25S-diastereoisomer of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan- 26-oic acid was obtained by vigorous hydrolysis of the bile of Alligator mississippiensis followed by repeated crystallization of the hydrolysate, and the 25R-diastereoisomer was isolated by hydrolysis of the bile salts in bile of A mississippiensis with rat feces. Acetylation of the 25R- or 25S-diastereoisomer of methyl 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid under controlled conditions yielded the corresponding 3 alpha,7 alpha-diacetate in approximately 70% yield. The diacetate was quantitatively oxidized to methyl 3 alpha,7 alpha-diacetoxy-12-oxo-5 beta-cholestan-26-oate, which was converted into the 12-tosylhydrazone in approximately 58% yield. Reduction of the tosylhydrazone with sodium borohydride in acetic acid yielded the 25R- or the 25S-diastereoisomer of 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid as the major product. Purification via column chromatography yielded the pure diastereoisomers in approximately 25% overall yield. The two diastereoisomers were resolved on thin-layer chromatography and high-performance liquid chromatography. When the bile of A mississippiensis was hydrolyzed with rat fecal bacteria, the 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid isolated via chromatographic purification was shown to be the 25R-diastereoisomer. PMID:1519259

Batta, A K; Mirchandani, R; Salen, G; Shefer, S

1992-04-01

442

Evidence for an extended structure of the T-cell co-receptor CD8 alpha as deduced from the hydrodynamic properties of soluble forms of the extracellular region.  

PubMed

We expressed soluble forms of the human T-cell coreceptor CD8 alpha extracellular region, CD8 alpha 161, and the amino-terminal immunoglobulin-like domain, CD8 alpha 114, in Chinese hamster ovary cells and Escherichia coli, respectively. Both molecules were readily purified to homogeneity in milligram amounts and were recognized by a large panel of monoclonal antibodies. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated that approximately 70% of CD8 alpha 161 was secreted as a disulfide-linked dimer, but CD8 alpha 114 was not disulfide-linked. To investigate the structural features of CD8 alpha 161 and CD8 alpha 114 under native conditions, we performed gel filtration and sucrose gradient sedimentation analysis. In spite of being partially or totally noncovalently bound, both recombinant molecules were stably associated homodimers, as no monomers could be detected at a fairly low protein concentration (approximately 1 microM). This suggests that the CD8 alpha amino-terminal domain alone strongly contributes to chain association. Determination of the Stokes radius (Rs) and sedimentation coefficient (s20,w) gave results consistent with CD8 alpha 114 having a globular shape and CD8 alpha 161 being an asymmetric molecule. Taking into account the contribution of hydration to the frictional coefficient, we obtained for CD8 alpha 161 an axial ratio of approximately 5, when modeled as a prolate ellipsoid. These results indicate that the elongated structure of CD8 alpha 161 is essentially contributed by the hinge region and help to explain how the CD8 alpha is able to bridge the distance between the T-cell surface and its binding site in the alpha 3 domain of major histocompatibility complex class I molecules on the target cell. PMID:8420975

Boursier, J P; Alcover, A; Herve, F; Laisney, I; Acuto, O

1993-01-25

443

Alpha Magnetic Spectrometer (AMS) Overview  

NASA Video Gallery

The Alpha Magnetic Spectrometer (AMS) is flying to the station on STS-134. The AMS experiment is a state-of-the-art particle physics detector being operated by an international team composed of 60 institutes from 16 countries and organized under United States Department of Energy (DOE) sponsorship. The AMS Experiment will use the unique environment of space to advance knowledge of the universe and lead to the understanding of the universe’s origin. The AMS is a high profile space-based particle physics experiment that is led by Nobel laureate Samuel Ting of the Massachusetts Institute of Technology (MIT).

Mark Garcia

2011-04-19

444

High gas flow alpha detector  

DOEpatents

An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors. 4 figs.

Bolton, R.D.; Bounds, J.A.; Rawool-Sullivan, M.W.

1996-05-07

445

Targeted alpha therapy for cancer  

NASA Astrophysics Data System (ADS)

Targeted alpha therapy (TAT) offers the potential to inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The practicality and efficacy of TAT is tested by in vitro and in vivo studies in melanoma, leukaemia, colorectal, breast and prostate cancers, and by a phase 1 trial of intralesional TAT for melanoma. The alpha-emitting radioisotope used is Bi-213, which is eluted from the Ac-225 generator and chelated to a cancer specific monoclonal antibody (mab) or protein (e.g. plasminogen activator inhibitor-2 PAI2) to form the alpha-conjugate (AC). Stable alpha-ACs have been produced which have been tested for specificity and cytotoxicity in vitro against melanoma (9.2.27 mab), leukaemia (WM60), colorectal (C30.6), breast (PAI2, herceptin), ovarian (PAI2, herceptin, C595), prostate (PAI2, J591) and pancreatic (PAI2, C595) cancers. Subcutaneous inoculation of 1-1.5 million human cancer cells into the flanks of nude mice causes tumours to grow in all mice. Tumour growth is compared for untreated controls, nonspecific AC and specific AC, for local (subcutaneous) and systemic (tail vein or intraperitoneal) injection models. The 213Bi-9.2.27 AC is injected into secondary skin melanomas in stage 4 patients in a dose escalation study to determine the effective tolerance dose, and to measure kinematics to obtain the equivalent dose to organs. In vitro studies show that TAT is one to two orders of magnitude more cytotoxic to targeted cells than non-specific ACs, specific beta emitting conjugates or free isotopes. In vivo local TAT at 2 days post-inoculation completely prevents tumour formation for all cancers tested so far. Intra-lesional TAT can completely regress advanced sc melanoma but is less successful for breast and prostate cancers. Systemic TAT inhibits the growth of sc melanoma xenografts and gives almost complete control of breast and prostate cancer tumour growth. Intralesional doses up to 450 µCi in human patients are effective in regressing melanomas, with no concomitant complications. These results point to the application of local and systemic TAT in the management of secondary cancer. Results of the phase 1 clinical trial of TAT of subcutaneous, secondary melanoma indicate proof of the principle that TAT can make tumours in patients regress.

Allen, Barry J.; Raja, Chand; Rizvi, Syed; Li, Yong; Tsui, Wendy; Zhang, David; Song, Emma; Qu, Chang Fa; Kearsley, John; Graham, Peter; Thompson, John

2004-08-01

446

Inert-gas energy-accommodation coefficients on tungsten  

Microsoft Academic Search

Measurements have been made of the energy-accommodation coefficients for inert gases on the thermally cleaned and partially controllable surface of tungsten at about 300°K under conditions of oil-free pumping.

S. F. Borisov; Yu. G. Semenov; P. E. Suetin

1982-01-01

447

Transport coefficients of the Widom-Rowlinson mixture  

NASA Astrophysics Data System (ADS)

In continuation of a previous paper on the static properties of the Widom-Rowlinson (WR) model mixture, we determine the thermal transport coefficients of that model by molecular-dynamics (MD) calculations and kinetic theory. The MD computations indicate that good accuracy can be obtained for the diffusion coefficient, the bulk and the shear viscosities, as well as for the thermal conductivity in a large region of densities. In contrast, the determination of the Soret coefficient poses problems and is planned to be treated in a separate publication. Comparison of the MD-generated transport coefficients with the kinetic theoretical results show remarkably good agreement over a range of densities that even includes the phase separation region. One main reason for this good agreement is certainly the accurate information for the thermodynamic properties of the WR model used in the kinetic theory expressions.

Luo, H.; Hoheisel, C.; Karkheck, J.

1990-10-01

448

Varistor composites with a positive temperature coefficient of resistance  

NASA Astrophysics Data System (ADS)

Varistor-type composites with a positive temperature coefficient of resistance based on metal oxide ceramics and polyethylene are developed. The feasibility of controlling the voltage at nominal current of these nonlinear elements is shown.

Lyashkov, A. Yu.; Tonkoshkur, A. S.

2011-03-01

449

Condensation film coefficients for mixtures of isobutane and isopentane  

SciTech Connect

Research designed to obtain baseline data on heat transfer for working fluids in geothermal binary cycle systems is described. The working fluid loop in the experimental apparatus simulates the binary cycle with steam as the heating fluid and a throttling valve instead of the turbine. Data on film coefficient for the condensation of 90/10 and 80/20 mixtures of isobutane-isopentane on a horizontal tube at various temperatures and condensation rates are presented. Data indicate that mixtures of isobutane-isopentane have lower condensation film coefficients than that of the pure isobutane under equivalent conditions of temperatures and condensation rates. Depending on the mass condensation rate, the film coefficient for the 80/20 mixture can be as low as 30 percent of the film coefficient for pure isobutane at the same mass condensation rate.

Tleimat, B.W.; Rie, H.; Laird, A.D.K.; Zhao, S.

1980-05-01

450

The solubility and diffusion coefficient of helium in uranium dioxide  

NASA Astrophysics Data System (ADS)

The solubility and diffusion coefficient of helium in the single-crystal UO2 samples were determined by a Knudsen-effusion mass-spectrometric method. The measured helium solubilities were found to lie within the scatter of the available data, but to be much lower than those for the polycrystalline samples. The diffusion analysis was conducted based on a hypothetical equivalent sphere model and the simple Fick's law. The helium diffusion coefficient was determined by using the pre-exponential factor and activation energy as the fitting parameters for the measured and calculated fractional releases of helium. The optimized diffusion coefficients were in good agreement with those obtained by a nuclear reaction method reported in the past. It was also found that the pre-exponential factors of the determined diffusion coefficients were much lower than those analyzed in terms of a simple interstitial diffusion mechanism.

Nakajima, Kunihisa; Serizawa, Hiroyuki; Shirasu, Noriko; Haga, Yoshinori; Arai, Yasuo

2011-12-01

451

Temperature and Strain Coefficient of Velocity for Langasite SAW Devices.  

National Technical Information Service (NTIS)

Surface Acoustic Wave sensors on Langasite substrates are being investigated for aerospace applications. Characterization of the Langasite material properties must be performed before sensors can be installed in research vehicles. The coefficients of velo...

G. M. Atkinson W. C. Wilson

2013-01-01

452

Determination of Catalytic Coefficient for a First-Order Reaction  

ERIC Educational Resources Information Center

|Describes an undergraduate physical chemistry experiment in which the acid catalyzed hydrolysis of sucrose is used to determine the catalytic coefficient of the hydronium ion, the catalyst in this reaction. (MLH)|

Fraga, E. R.; And Others

1975-01-01

453

A database of selected transport coefficients for combustion studies  

SciTech Connect

COYOTE and similar combustion programs based on the multicomponent Navier-Stokes equations require the mixture viscosity, thermal conductivity, and species transport coefficients as input. This report documents a significant improvement to the calculation of these molecular transport coefficients in COYOTE and provides a self-contained and easy-to-use source of such data in a format suitable for use by such programs. We present the data for various species in two forms. The first is a simple functional fit to the transport coefficients. The second is the use of tabulated Lennard-Jones parameters in simple theoretical expressions for the gas-phase transport coefficients. Tables are given for a number of chemical species.

Cloutman, L.D.

1993-08-01

454

Development of Vertical Dispersion Coefficients for Deep-Valley Terrain.  

National Technical Information Service (NTIS)

Results are reported from studies conducted to determine reliable dispersion coefficients for use with the Gaussian plume model, that will represent a broader range of topographic conditions than was intended for the standard Pasquill-Gifford values. Tota...

D. H. Minott D. L. Shearer R. S. Marker

1977-01-01

455

Gamma ray attenuation coefficient measurement for neutron-absorbent materials  

NASA Astrophysics Data System (ADS)

The compounds Na2B4O7, H3BO3, CdCl2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the ? rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H3BO3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

Jalali, Majid; Mohammadi, Ali

2008-05-01

456

Correlation equation for the marine drag coefficient and wave steepness  

NASA Astrophysics Data System (ADS)

This work questions, starting from dimensional considerations, the generality of the belief that the marine drag coefficient levels off with increasing wind speed. Dimensional analysis shows that the drag coefficient scales with the wave steepness as opposed to a wave-age scaling. A correlation equation is employed here that uses wave steepness scaling at low aspect ratios (inverse wave steepnesses) and a constant drag coefficient at high aspect ratios. Invoked in support of the correlation are measurements sourced from the literature and at the FINO1 platform in the North Sea. The correlation equation is then applied to measurements recorded from buoys during the passage of hurricanes Rita, Katrina (2005) and Ike (2008). Results show that the correlation equation anticipates the expected levelling off in deeper water, but a drag coefficient more consistent with a Charnock type relation is also possible in more shallower water. Some suggestions are made for proceeding with a higher-order analysis than that conducted here.

Foreman, Richard J.; Emeis, Stefan

2012-09-01

457

Temperature Coefficient of the Unperturbed Dimensions of Polyoxyethylene.  

National Technical Information Service (NTIS)

The determination of the temperature coefficient of the mean-square length of a polymer chain from thermoelastic measurements on swollen networks is discussed. Failure to take proper account of changes of dilation with temperature may lead to serious erro...

J. E. Mark P. J. Flory

1972-01-01

458

A threat coefficient method for extended air defense system analysis  

NASA Astrophysics Data System (ADS)

The extended air defense system has been analyzed. The Particular attention is paid to the threat of the air defense system to cruise missile. A method named Threat Coefficient Method was proposed based on the analysis of the air defense system structure and its operations. A threat coefficient model of the air defense system was built. It is shown that the threat coefficient will be reduced while threat-length is reduced by using the model. The threat-length has been researched based on radar theory. The method has been verified by means of simulation. Based on the analysis, it is found that reducing the RCS or increasing active chaff could reduce the threat coefficient.

Yin, Zhihong; Cui, Naigang; Guan, Shiyi

2007-11-01

459

Experimental techniques for the measurement of diffusion coefficients  

SciTech Connect

This paper describes techniques for the measurement of diffusion coefficients in solids. The focus is on depth profiling by various ion beam techniques, especially secondary ion mass spectrometry, Rutherford backscattering, and nuclear reaction analysis. 35 refs., 10 figs.

Rothman, S.J.

1989-03-01

460

Internal Conversion Coefficients - How good are They Now.  

National Technical Information Service (NTIS)

Internal conversion coefficients (ICC) convey important information about the atomic nucleus. Through comparison of experimental ICCs with corresponding theoretical values, multipolarities and mixing ratios of nuclear transitions are determined. As well a...

C. W. Nestor M. B. Trzhaskovskaya P. M. Davidson T. Kib'edil T. W. Burrows

2007-01-01

461

Declared value for the thermal conductivity coefficient of insulation corkboard  

Microsoft Academic Search

Summary This study presents the results of a set of tests for the determination of the thermal conductivity coefficient of samples extracted from boards of Insulation Corkboard (ICB) withdrawn from the usual production of the seven portuguese factories.

L. Matias; C. Santos; M. Reis; L. Gil

1997-01-01

462

Clustering coefficient and community structure of bipartite networks  

NASA Astrophysics Data System (ADS)

Many real-world networks display natural bipartite structure, where the basic cycle is a square. In this paper, with the similar consideration of standard clustering coefficient in binary networks, a definition of the clustering coefficient for bipartite networks based on the fraction of squares is proposed. In order to detect community structures in bipartite networks, two different edge clustering coefficients LC4 and LC3 of bipartite networks are defined, which are based on squares and triples respectively. With the algorithm of cutting the edge with the least clustering coefficient, communities in artificial and real world networks are identified. The results reveal that investigating bipartite networks based on the original structure can show the detailed properties that is helpful to get deep understanding about the networks.

Zhang, Peng; Wang, Jinliang; Li, Xiaojia; Li, Menghui; di, Zengru; Fan, Ying

2008-12-01

463

Comparison of optimal quantizations of speech reflection coefficients  

Microsoft Academic Search

Four quantization schemes for the reflection coefficients obtained from linear prediction speech analysis are theoretically compared. The asymptotic performance of each scheme is developed and compared using various definitions of \\

R. M. Gray; J. D. Markel

1977-01-01

464

Probability Density Function of the Red Cell Membrane Permeability Coefficient  

PubMed Central

The distribution of a random variable is determined by the probability density functions (PDF) of all other random variables with which the variable in question is jointly distributed. If the PDF of the random variable of interest is normal, or skewed normal, then the distributions with which it is jointly distributed determine its mean and standard deviation. In the case described here (where hemolysis time of the red blood cell is a function of the permeability coefficient and geometric variables of the cell) the mean and standard deviation of the permeability coefficient and the known distributions of the geometric variables on which the hemolysis time depends determine a predicted distribution of hemolysis time. An observed distribution of the hemolysis time is obtained spectrophotometrically. By choosing the mean and standard deviation of the permeability coefficient so that the predicted PDF of the hemolysis time matches the observed PDF best by least-squares criterion, the complete distribution of the permeability coefficient is determined.

Saari, Jack T.; Beck, James S.

1974-01-01

465

Measurement of heat transfer coefficients by nuclear magnetic resonance.  

PubMed

We demonstrate an experimental method for the measurement of heat transfer coefficient for a fluid system by magnetic resonance imaging. In this method, the temporal variation of thermally induced nuclear shielding is monitored and the average heat transfer coefficient is measured as a function of fluid velocity. We examine the cases of natural convection and forced convection at fluid velocity up to 0.8 m s(-1). These cases correspond to low dimensionless Biot (Bi) number where the heat transfer is limited by thermal convection. We demonstrate the NMR method for two simple geometries, a cylinder and a sphere, to experimentally determine the heat transfer coefficient (h) in two NMR imaging and spectroscopy systems through measuring three NMR parameters, the chemical shift, magnetization and spin self diffusion coefficient. PMID:18524523

Gultekin, David H; Gore, John C

2008-06-03

466

Seal assembly for materials with different coefficients of thermal expansion  

DOEpatents

Seal assembly comprising (a) two or more seal elements, each element having having a coefficient of thermal expansion; and (b) a clamping element having a first segment, a second segment, and a connecting segment between and attached to the first and second segments, wherein the two or more seal elements are disposed between the first and second segments of the clamping element. The connecting segment has a central portion extending between the first segment of the clamping element and the second segment of the clamping element, and the connecting segment is made of a material having a coefficient of thermal expansion. The coefficient of thermal expansion of the material of the connecting segment is intermediate the largest and smallest of the coefficients of thermal expansion of the materials of the two or more seal elements.

Minford, Eric (Laurys Station, PA)

2009-09-01

467

Neural Network Prediction of New Aircraft Design Coefficients.  

National Technical Information Service (NTIS)

This paper discusses a neural network tool for more effective aircraft design evaluations during wind tunnel tests. Using a hybrid neural network optimization method, we have produced fast and reliable predictions of aerodynamical coefficients, found opti...

M. Norgaard C. C. Jorgensen J. C. Ross

1997-01-01

468

Distinct diffusion coefficients in binary nonelectrolyte mixtures. Frames of reference  

SciTech Connect

Generalized transport coefficients are indispensable for the study of interactions between species of the same kind in binary solutions. Distinct diffusion coefficients are best suited for this purpose because of their finite limiting values and inherent symmetry. Equations are derived for the calculation of these coefficients from experimental data for the mass-, volume-, number-, and solvent-fixed frames of reference. Distinct diffusion coefficients in the 4 reference frames computed for 14 binary nonelectrolyte solutions show that the number-fixed frame is probably best suited for the comparison of the macroscopic properties of these solutions. A point of contention has been the frame of reference of the Friedman-Mills equation; surprisingly, the mass-fixed frame describes its D[sub ij][sup d] values closely. 19 refs., 12 figs., 4 tabs.

Mills, R.; Malhotra, R.; Woolf, L.A. (Australian National Univ., Canberra (Australia)); Miller, D.G. (Lawrence Livermore National Lab., CA (United States))

1994-05-26

469

Total Internal Reflection Coefficient of Plastic Oscillators and Light Pipes.  

National Technical Information Service (NTIS)

The formula describing the dependence of the disturbed total internal reflection coefficient on the angle of light arrival in plastic scintillators and light pipes is suggested. Good agreement with the experimental data obtained in other papers is shown. ...

A. I. Peresypkin

1985-01-01

470

On cloud modelling and the mass accommodation coefficient of water  

NASA Astrophysics Data System (ADS)

The mass accommodation coefficient of water is a quantity for which different experimental techniques have yielded conflicting values in the range 0.04-1. From the viewpoint of cloud modelling, this is an unfortunate situation, since the value of the mass accommodation coefficient affects the model results, e.g. the number concentration of activated cloud droplets. In this paper we argue that a mass accommodation coefficient of unity should be used in cloud modelling, since this value has been obtained in experimental studies of water droplet growth rates, a quantity which is explicitly described in cloud models. In contrast, mass accommodation coefficient values below unity have been derived from experimental results which are analyzed with different theoretical expressions than those included in cloud models.

Laaksonen, A.; Vesala, T.; Kulmala, M.; Winkler, P. M.; Wagner, P. E.

2004-11-01

471

Dispersion of thermooptic coefficients of soda-lime-silica glasses  

SciTech Connect

The thermooptic coefficients, i.e., the variation of refractive index with temperature (dn/dT), are analyzed in a physically meaningful model for two series of soda-lime-silica glasses. 25Na{sub 2}O{center_dot}xCaO{center_dot}(75 {minus} x)SiO{sub 2} and (25 {minus} x)Na{sub 2}O{center_dot}xCaO {center_dot} 75SiO{sub 2}. This model is based on three physical parameters--the thermal expansion coefficient and excitonic and isentropic optical bands that are in the vacuum ultraviolet region--instead of on consideration of the temperature coefficient of electronic polarizability, as suggested in 1960. This model is capable of predicting and analyzing the thermooptic coefficients throughout the transmission region of the optical glasses at any operating temperature.

Ghosh, G. [Electrotechnical Lab., Tsukuba, Ibaraki (Japan). Light and Radio Waves Section

1995-01-01

472

A semiparametric recurrent events model with time-varying coefficients.  

PubMed

We consider a recurrent events model with time-varying coefficients motivated by two clinical applications. We use a random effects (Gaussian frailty) model to describe the intensity of recurrent events. The model can accommodate both time-varying and time-constant coefficients. We use the penalized spline method to estimate the time-varying coefficients. We use Laplace approximation to evaluate the penalized likelihood without a closed form. We estimate the smoothing parameters in a similar way to variance components. We conduct simulations to evaluate the performance of the estimates for both time-varying and time-independent coefficients. We apply this method to analyze two data sets: a stroke study and a child wheeze study. PMID:22903343

Yu, Zhangsheng; Liu, Lei; Bravata, Dawn M; Williams, Linda S; Tepper, Robert S

2012-08-18

473

Determination of the scattering coefficient, the reduced scattering coefficient, and the anisotropy factor of tissue with differential interference contrast microscopy  

NASA Astrophysics Data System (ADS)

We report an approach for determination of the scattering coefficient, the reduced scattering coefficient, and the anisotropy factor from the quantitative phase map measured by differential interference contrast microscopy based on the scatteringphase theorem. The approach is first validated by showing the excellent agreement between the retrieved optical properties of polystyrene spheres and Intralipid-20% suspension and their known values. The scattering properties of unstained pathological prostate cancer slides and fresh cancerous and normal colon tissue samples are then investigated. A clear trend with cancer in the reduced scattering coefficient and the anisotropy factor is shown. The potential of the approach for tissue diagnosis is discussed at the end.

Deangelo, Bianca; Arzumanov, Grant; Shanley, Patrick; Xu, Zhang; Xu, M.

2012-02-01

474

Friction Coefficient Measurement of Hydrogel Materials on Living Epithelial Cells  

Microsoft Academic Search

Soft biomaterials are often used in applications that involve contact and relative motion against biological tissues, as well\\u000a as complicated and variable environments. The friction coefficient of these contacts involving living human cells is of key\\u000a importance in the analysis and success of these devices. This work measures the contacting friction coefficient between soft\\u000a hydrogel biomaterial surfaces against live human

Alison C. Dunn; Jessica A. Cobb; Ana N. Kantzios; Sung Jin Lee; Malisa Sarntinoranont; Roger Tran-Son-Tay; W. Gregory Sawyer

2008-01-01

475

Buchdahl's glass dispersion coefficients calculated from Schott equation constants.  

PubMed

A method for the rapid evaluation of Buchdahl's dispersion coefficients at an arbitrary base wavelength given the Schott equation constants is presented. Buchdahl's chromatic coordinate transformation is performed on the Schott equation for the refractive index. A Taylor series expansion of the transformed Schott equation is then equated to the square of the Buchdahl dispersion model. Equations for Buchdahl's dispersion coefficients are then obtained for any base wavelength by matching the power of Buchdahl's chromatic coordinate omega out to fourth order. PMID:20555731

Reardon, P J; Chipman, R A

1989-08-15

476

The Calculation of X-Ray Mass Absorption Coefficients  

Microsoft Academic Search

An empirical method of calculating mass absorption coefficients is given. Complete tables of constants are presented for calculating ??&rgr; for all elements and for wave-lengths less than the K critical absorption wave-length. Partial tables give constants for wave-lengths between the L1 and M1 critical wave-lengths.Calculated mass absorption coefficients are given for the common elements.

John A. Victoreen

1949-01-01

477

Improved Coulomb barrier transmission coefficient for nuclear fusion cross sections  

Microsoft Academic Search

Higher energy ([approx gt]20 keV) data are customarily extrapolated by using the Gamow transmission coefficient to estimate the nonresonance nuclear fusion reaction cross sections [sigma](E) for charged particles at low energies (<20 keV), which are needed for fusion energy production and astrophysical calculations. A general extrapolation method is presented based on a more realistic Coulomb barrier transmission coefficient that can

Y. E. Kim; A. L. Zubarev

1994-01-01

478

Interaction corrections to the Hall coefficient at intermediate temperatures  

Microsoft Academic Search

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

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

2001-01-01

479

Bearing Dynamic Coefficients of Flexible-Pad Journal Bearings  

Microsoft Academic Search

The application of flexible-pad journal bearings for high-speed rotating machinery has recently gained attention from equipment manufacturers for its simplicity of one-piece design which can eliminate the manufacturing tolerance stack-up and possible lower functional power loss. This paper presents a general method for the calculation of bearing dynamic coefficients of flexible-pad journal bearings. These coefficients are critical to the rotor

Wen Jeng Chen

1995-01-01

480

Calculation of diffusion coefficients in air-metal thermal plasmas  

Microsoft Academic Search

This paper presents the combined diffusion coefficients of metal vapours (silver, copper and iron) in air thermal plasmas for temperatures ranging from 300 to 30 000 K. The theory used to calculate these coefficients is remembered and validated by comparison with the literature values in several cases such as Ar-He, Ar-Cu and N2-O2 mixtures. The results are discussed showing the

Y. Cressault; A. Gleizes

2010-01-01

481

Granular Gases with Impact-Velocity-Dependent Restitution Coefficient  

Microsoft Academic Search

We consider collisional models for granular particles and analyze the conditions under which the restitution coefficient might\\u000a be a constant. We show that these conditions are not consistent with known collision laws. From the generalization of the\\u000a Hertz contact law for viscoelastic particles we obtain the coefficient of normal restitution ? as a function of the normal\\u000a component of the

Nikolai V. Brilliantov; Thorsten Poeschel

2001-01-01

482

Americium speciation and distribution coefficients in a granitic ground water  

Microsoft Academic Search

The possible importance of pH-dependent speciation in determining the distribution coefficient of americium in a granitic ground water is discussed. The authors obtained experimental distribution coefficients for americium. The authors used the geochemical code PHREEQE to calculate the amount present of americium complexes with hydroxides and carbonates over a range of pH, using formation constants taken from the literature and

G. W. Beall; W. W. L. Lee; A. E. Van Luik

1986-01-01

483

Diffusion coefficient and shear viscosity of rigid water models  

Microsoft Academic Search

We report the diffusion coefficient and viscosity of popular rigid water models: two non-polarizable ones (SPC\\/E with three sites, and TIP4P\\/2005 with four sites) and a polarizable one (Dang–Chang, four sites). We exploit the dependence of the diffusion coefficient on the system size (Yeh and Hummer 2004 J. Phys. Chem. B 108 15873) to obtain the size-independent value. This also

Sami Tazi; Alexandru Bo?an; Mathieu Salanne; Virginie Marry; Pierre Turq; Benjamin Rotenberg

2012-01-01

484

A theory on the discharge coefficient for safety relief valve  

Microsoft Academic Search

Comparing the flow through an SRV to that through an orifice, a simple theory is proposed to relate the discharge coefficient in two-phase compressible flow to the value in liquid incompressible flow. This approach made use of the author’s omega method applicable for both flashing discharge and non-flashing discharge. The two-phase discharge coefficient is shown to be a smooth function

Joseph C. Leung

2004-01-01

485

Dynamic sagittal flexibility coefficients of the human cervical spine  

Microsoft Academic Search

The goal of the present study was to determine the dynamic sagittal flexibility coefficients, including coupling coefficients, throughout the human cervical spine using rear impacts. A biofidelic whole cervical spine model (n=6) with muscle force replication and surrogate head was rear impacted at 5g peak horizontal accelerations of the T1 vertebra within a bench-top mini-sled. The dynamic main and coupling

Paul C. Ivancic; Shigeki Ito; Manohar M. Panjabi

2007-01-01

486

Pfaffianization of the variable-coefficient Kadomtsev Petviashvili equation  

Microsoft Academic Search

This paper constructs more general exact solutions than N-soliton solution and Wronskian solution for variable-coefficient Kadomtsev–Petviashvili (KP) equation. By using the Hirota method and Pfaffian technique, it finds the Grammian determinant-type solution for the variable-coefficient KP equation (VCKP), the Wronski-type Pfaffian solution and the Gram-type Pfaffian solutions for the Pfaffianized VCKP equation.

Qing-Fan Zhang; En-Gui Fan

2007-01-01

487

Sensitivity of tropical cyclone models to the surface exchange coefficients  

Microsoft Academic Search

Motivated by recent developments in tropical cyclone dynamics, this paper examines the sensitivity of tropical-cyclone models to the surface exchange coefficients of momentum and heat (enthalpy) in a three-dimensional, non-hydrostatic, and cloud-representing context. Previous theoretical and numerical studies of the sensitivity in axisymmetric models have found that the intensity decreases markedly with increasing drag coefficient. Contrary to prior theoretical studies

Michael T. Montgomery; Roger K. Smith; Sang V. Nguyen

488

Estimating Linear Restrictions on Regression Coefficients for Multivariate Normal Distributions  

Microsoft Academic Search

In this paper linear restrictions on regression coefficients are studied. Let the $p \\\\times q_2$ matrix of coefficients of regression of the $p$ dependent variates on $q_2$ of the independent variates be $\\\\mathbf{\\\\bar B}_2$. Maximum likelihood estimates of an $m \\\\times p$ matrix $\\\\Gamma$ satisfying $\\\\Gamma'\\\\mathbf{\\\\bar B}_2 = 0$ and certain other conditions are found under the assumption that the

T. W. Anderson

1951-01-01

489

Eddy diffusion coefficients in the lower thermospheres, revised  

NASA Astrophysics Data System (ADS)

The seasonal variation of the eddy diffusion coefficient is deduced for a height of 94 km at 23 S based on two independent methods of analysis. One of these methods is related to indirect measurements of atomic oxygen and the other one is a new method related to measurements of the density of upper atmospheric sodium. The results are mutually consistent giving a maximum eddy diffusion coefficient during summer.

Kirchhoff, V. W. J. H.; Clemesha, B. R.

1982-08-01

490

Influence of pixel geometry on the 1/f noise coefficient  

NASA Astrophysics Data System (ADS)

This paper presents a systematic study of the 1/f noise coefficient as a function of pixel geometry for microbolometer structures. Structures with various VOx widths, electrode gaps, electrode widths and via hole sizes were fabricated and characterized. The experimental results show that the 1/f noise coefficient is adversely affected by current non uniformity, in agreement with model predictions. Design parameters that significantly impact current non uniformity are identified and approaches to minimize their importance are proposed.

Généreux, Francis; Paultre, Jacques-Edmond; Tremblay, Bruno; Provençal, Francis; Alain, Christine

2013-06-01

491

Coefficient de Condensation de Couches Minces de Fluorures  

Microsoft Academic Search

\\u000a Summary  The condensation coefficient of lithium and lanthanum fluorids has been measured determining the thichnesses of the thin films\\u000a grown simultaneously on supports kept during film formation at temperatures from 25 °C to 500 °C. It is found that the condensation\\u000a coefficient is equal to 1 for LaF3 at 55 °C and for LiF at 60 °C, being less than 1

A. Bourg; M. Bourg; F. Porreca

1967-01-01

492

Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20-250 MeV.  

PubMed

Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations <20 MeV on the kerma approximation, which assumes that charged particle secondaries are locally deposited, or at least that charged particle equilibrium exists within the tally cell volume. However, with increasing neutron energy the kerma approximation may no longer be valid for some energetic secondaries such as protons. The Los Alamos Monte Carlo radiation transport code MCNPX was used for all absorbed dose calculations. Transport models and collision-based energy deposition tallies were used for neutron energies >20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks <20 MeV, kerma factors were used to obtain absorbed dose. Results are presented for a discrete set of angles of incidence on an ICRU tissue slab phantom. PMID:19887515

Olsher, R H; McLean, T D; Justus, A L; Devine, R T; Gadd, M S

2009-11-03

493

Atmospheric Density Corrections Estimated from Fitted Drag Coefficients  

NASA Astrophysics Data System (ADS)

Fitted drag coefficients estimated using GEODYN, the NASA Goddard Space Flight Center Precision Orbit Determination and Geodetic Parameter Estimation Program, are used to create density corrections. The drag coefficients were estimated for Stella, Starlette and GFZ using satellite laser ranging (SLR) measurements; and for GEOSAT Follow-On (GFO) using SLR, Doppler, and altimeter crossover measurements. The data analyzed covers years ranging from 2000 to 2004 for Stella and Starlette, 2000 to 2002 and 2005 for GFO, and 1995 to 1997 for GFZ. The drag coefficient was estimated every eight hours. The drag coefficients over the course of a year show a consistent variation about the theoretical and yearly average values that primarily represents a semi-annual/seasonal error in the atmospheric density models used. The atmospheric density models examined were NRLMSISE-00 and MSIS-86. The annual structure of the major variations was consistent among all the satellites for a given year and consistent among all the years examined. The fitted drag coefficients can be converted into density corrections every eight hours along the orbit of the satellites. In addition, drag coefficients estimated more frequently can provide a higher frequency of density correction.

McLaughlin, C. A.; Lechtenberg, T. F.; Mance, S. R.; Mehta, P.

2010-12-01

494

A physical interpretation of the phenomenological coefficients of membrane permeability.  

PubMed

A "translation" of the phenomenological permeability coefficients into friction and distribution coefficients amenable to physical interpretation is presented. Expressions are obtained for the solute permeability coefficient omega and the reflection coefficient sigma for both non-electrolytic and electrolytic permeants. An analysis of the coefficients is given for loose membranes as well as for dense natural membranes where transport may go through capillaries or by solution in the lipoid parts of the membrane. Water diffusion and filtration and the relation between these and capillary pore radius of the membrane are discussed. For the permeation of ions through the charged membranes equations are developed for the case of zero electrical current in the membrane. The correlation of sigma with omega and L(p) for electrolytes resembles that for non-electrolytes. In this case omega and sigma depend markedly on ion concentration and on the charge density of the membrane. The reflection coefficient may assume negative values indicating anomalous osmosis. An analysis of the phenomena of anomalous osmosis was carried out for the model of Teorell and Meyer and Sievers and the results agree with the experimental data of Loeb and of Grim and Sollner. A set of equations and reference curves are presented for the evaluation of omega and sigma in the transport of polyvalent ions through charged membranes. PMID:13752127

KEDEM, O; KATCHALSKY, A

1961-09-01

495

Flux-limited diffusion coefficient applied to reactor analysis  

NASA Astrophysics Data System (ADS)

A new definition of the diffusion coefficient for use in reactor physics calculations is evaluated in this thesis. It is based on naturally flux-limited diffusion theory (FDT), sometimes referred to as Levermore-Pomraning diffusion theory. Another diffusion coefficient more loosely based on FDT is also evaluated in this thesis. Flux-limited diffusion theory adheres to the physical principle of flux-limiting, which is that the magnitude of neutron current is not allowed to exceed the scalar flux. Because the diffusion coefficients currently used in the nuclear industry are not flux-limited they may violate this principle in regions of large spatial gradients, and because they encompass other assumptions, they are only accurate when used in the types of calculations for which they were intended. The evaluations were performed using fine-mesh diffusion theory. They are in one spatial dimension and in 47, 4, and 2 energy groups, and were compared against a transport theory benchmark using equivalent energy structures and spatial discretizations. The results show that the flux-limited diffusion coefficient (FD) outperforms the standard diffusion coefficient in calculations of single assemblies with vacuum boundaries, according to flux- and eigenvalue-errors. In single assemblies with reflective boundary calculations, the FD yielded smaller improvements, and tended to improve only the fast-group results. The results also computationally confirm that the FD adheres to flux-limiting, while the standard diffusion coefficient does not.

Keller, Steven Ede

496

Thermodynamics of concentrated electrolyte mixtures. 9. Activity coefficients in aqueous NaBr-CaBr/sub 2/ mixtures at 25 /sup 0/C  

SciTech Connect

The activity coefficients of NaBr and CaBr/sub 2/ in NaBr-CaBr/sub 2/ aqueous mixtures have been measured at 25/sup 0/C over the ranges of ionic strengths 0.1 to 7.5 m. The measurements were made with a dual electrometer amplifier using Na and Ca ion selective electrodes against a Br ion selective electrode. The data were fitted to Harned's equation of the form log ..gamma../sub i/ = log ..gamma../sub i//sup 0/ - ..cap alpha../sub AB/y/sub B/ - ..beta../sub AB/y/sub B//sup 2/ to compute the trace activity coefficients and were also analyzed by using the Pitzer formation. Deviations from the Pitzer formalism were observed for the experimental activity coefficients in this mixture.

Usha, A.V.; Raju, K.; Atkinson, G.

1987-08-27

497

{alpha} decay of {sup 105}Te  

SciTech Connect

The {alpha} decay of the neutron-deficient nuclide {sup 105}Te was observed. The {sup 50}Cr({sup 58}Ni,3n) reaction was used to produce {sup 105}Te nuclei. The {sup 105}Te residues were selected with the Argonne Fragment Mass Analyzer and implanted into a double-sided Si strip detector where their subsequent {alpha} decay was detected. An {alpha}-decay Q value of Q{sub {alpha}}=4900(50) keV and a half life of T{sub 1/2}=0.70(-0.17+0.25){mu}s were measured for {sup 105}Te and a reduced {alpha}-decay width of W{sub {alpha}}=3.3(-1.7+2.1) was deduced. The decay properties of {sup 105}Te are compared with those of heavier Te isotopes and theoretical predictions.

Seweryniak, D.; Davids, C.N.; Gros, S.; Khoo, T.L.; Peterson, D.; Robinson, A.; Zhu, S. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Starosta, K.; Vaman, C. [National Superconducting Cyclotron Laboratory, East Lansing, Michigan 48824 (United States); Hecht, A.A.; Hoteling, N.; Walters, W.B. [University of Maryland, College Park, Maryland 20742 (United States); Lagergren, K.; Woods, P.J. [Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States); Lotay, G. [University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)

2006-06-15

498

Production of fungal alpha-amylase by Saccharomyces kluyveri in glucose-limited cultivations.  

PubMed

Heterologous protein production by the yeast Saccharomyces kluyveri was investigated under aerobic glucose-limited conditions. Alpha-amylase from Aspergillus oryzae was used as model protein and the gene was expressed from a S. cerevisiae 2 micro plasmid. For comparison, strains of both S. kluyveri and S. cerevisiae were transformed with the same plasmid, which led to secretion of active alpha-amylase in both cases. The S. cerevisiae 2 micro plasmid was found to be stable in S. kluyveri as evaluated by a constant alpha-amylase productivity in a continuous cultivation for more than 40 generations. S. kluyveri and S. cerevisiae secreted alpha-amylase with similar yields during continuous cultivations at dilution rates of 0.1 and 0.2 h(-1) (4.8-5.7 mg (g dry weight)(-1)). At a dilution rate of 0.3 h(-1) the metabolism of S. kluyveri was fully respiratory, whereas S. cerevisiae produced significant amounts of ethanol. A fed-batch cultivation was carried out with S. kluyveri where the biomass concentration reached 85 g l(-1) and the alpha-amylase concentration reached 320 mg l(-1). Even though S. kluyveri could be grown to high cell density, it was also observed that it has a high maintenance coefficient, which resulted in low biomass yields at the low specific growth rates prevailing towards the end of the fed-batch cultivation. PMID:15246667

Møller, Kasper; Sharif, Mostafa Z; Olsson, Lisbeth

2004-08-01

499

Seventeen alpha-hydroxylase deficiency.  

PubMed

Seventeen alpha-hydroxylase deficiency (17OHD) is a rare form of congenital adrenal hyperplasia in which defects in the biosynthesis of cortisol and sex steroid result in mineralocorticoid excess, hypokalemic hypertension and sexual abnormalities such as pseudohermaphroditism in males, and sexual infantilism in females. The disease is inherited in an autosomal recessive pattern, and is caused by mutations in the gene encoding cytochrome P450c17 (CYP17), which is the single polypeptide that mediates both 17alpha-hydroxylase and 17,20-lyase activities. We report the case of a 15-year-old patient with 17OHD who had a female phenotype but male karyotype (46,XY). The diagnosis was made based on classical clinical features, biochemical data and molecular genetic study. Two mutations were identified by polymerase chain reaction amplification and sequencing, including a S106P point mutation in exon 2 and a 9-bp (GACTCTTTC) deletion from nucleotide position 1519 in exon 8 of CYP17. The first of these mutations was found in the father and the second in the mother, and both have been previously reported in Asia. The patient's hypertension and hypokalemia resolved after glucocorticoid replacement and treatment with potassium-sparing diuretics. Sex hormone replacement was prescribed for induction of sexual development and reduction of the final height. Prophylactic gonadectomy was scheduled. In summary, 17OHD should be suspected in patients with hypokalemic hypertension and lack of secondary sexual development so that appropriate therapy can be implemented. PMID:16477341

Wong, Siew-Lee; Shu, San-Ging; Tsai, Chi-Ren

2006-02-01

500

Alpha-1 antitrypsin augmentation therapy.  

PubMed

The therapy of alpha-1 antitrypsin deficiency (AATD) is an example of a medical triumph over a common hereditary disease. Based on the und