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Sample records for infinite dilution measurements

  1. Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium trifluorotris(perfluoroethyl)phosphate.

    PubMed

    Marciniak, Andrzej; Wlazło, Michał

    2010-05-27

    The activity coefficients at infinite dilution, gamma(13)(infinity), for 37 solutes, alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water, in the ionic liquid 1-(3-hydroxypropyl)pyridinium trifluorotris(perfluoroethyl)phosphate [N-C(3)OHPY][FAP] were determined by gas-liquid chromatography at the temperatures from 308.15 to 358.15 K. The partial molar excess enthalpies at infinite dilution values DeltaH(1)(E,infinity) were calculated from the experimental gamma(13)(infinity) values obtained over the temperature range. The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated from the gamma(13)(infinity) values and compared to the literature values for other ionic liquids, N-methylpyrrolidone (NMP) and sulfolane. It was found that the investigated [N-C(3)OHPY][FAP] ionic liquid shows much higher selectivity and capacity at infinite dilution than the generally used organic solvents such as NMP, sulfolane, and other ionic liquids. PMID:20429540

  2. Activity coefficients of chlorophenols in water at infinite dilution

    SciTech Connect

    Tabai, S.; Rogalski, M.; Solimando, R.; Malanowski, S.K.

    1997-11-01

    The total pressure of aqueous solutions of chlorophenols was determined by a ebulliometric total pressure method for the aqueous solutions of phenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenol in the temperature range from 40 to 90 C. The activity coefficients at infinite dilution and the Henry constants were derived.

  3. Molecular cage occupancy of clathrate hydrates at infinite dilution: experimental determination and thermodynamic significance.

    PubMed

    Seol, Jiwoong; Lee, Jong-Won; Kim, Do-Youn; Takeya, Satoshi; Ripmeester, John A; Lee, Huen

    2010-01-21

    This study focuses on the cage occupancy of guest molecules in the infinitely dilute state. At the extreme conditions of highly diluted guest concentrations the direct measurements of the cage occupancy ratio representing the competitive inclusion of multiguest species appear to be so difficult because of spectroscopic intensity limitation, but its thermodynamic significance might be considerable due to the fact that the infinite-dilution value of the cage occupancy ratio can provide the valuable thermodynamic information as a very unique and guest-specific parameter. To experimentally identify gaseous guest populations in structure I (sI) and structure II (sII) cages, we used the solid-state nuclear magnetic resonance (NMR), gas chromatography, and direct gas measurements. Furthermore, we derived the simple and generalized thermodynamic equation related to cage occupancies at infinite dilution from the van der Waals-Platteeuw model. Both experimental and predicted values agree well within the experimental error range. PMID:20000371

  4. Infinite determinantal measures and the ergodic decomposition of infinite Pickrell measures. II. Convergence of infinite determinantal measures

    NASA Astrophysics Data System (ADS)

    Bufetov, A. I.

    2016-04-01

    The second paper in this series is devoted to the convergence of sequences of infinite determinantal measures, understood as the convergence of sequences of the corresponding finite determinantal measures. Besides the weak topology in the space of probability measures on the space of configurations, we also consider the natural immersion (defined almost surely with respect to the infinite Bessel process) of the space of configurations into the space of finite measures on the half-line, which induces a weak topology in the space of finite measures on the space of finite measures on the half-line. The main results of the present paper are sufficient conditions for the tightness of families and the convergence of sequences of induced determinantal processes as well as for the convergence of processes corresponding to finite-rank perturbations of operators.

  5. Prediction of infinite dilution benzene solubility in linear polyethylene melts via the direct particle deletion method.

    PubMed

    De Angelis, Maria Grazia; Boulougouris, Georgios C; Theodorou, Doros N

    2010-05-20

    The solubility of benzene in linear polyethylene melts was estimated via Monte Carlo simulations using a united-atom molecular model at temperatures between 373 and 573 K, in the infinite dilution limit. The excess chemical potential of the solute was evaluated with the direct particle deletion (DPD) method, whose rigorous derivation is presented here in detail: in this scheme, the benzene molecule united atoms are converted to hard spheres and then removed from the polymer system. The simulations were carried out in the N(1)N(2)PT ensemble using advanced Monte Carlo moves to equilibrate the polymeric phase. The evaluation of the accessible volume fraction for the "hard sphere" solute molecule required by the DPD method was performed analytically. The effect of the value of the arbitrary hard sphere diameter, d, on the computed thermodynamic quantities was determined, allowing us to establish an optimal range for the system considered. The values of Henry's law constant are in good agreement with experimental data from the literature in the temperature range considered and are comparable to those obtained with the lattice fluid and PC(SAFT) equations of state for the same system. PMID:20426442

  6. Computation of infinite dilute activity coefficients of binary liquid alloys using complex formation model

    NASA Astrophysics Data System (ADS)

    Awe, O. E.; Oshakuade, O. M.

    2016-04-01

    A new method for calculating Infinite Dilute Activity Coefficients (γ∞s) of binary liquid alloys has been developed. This method is basically computing γ∞s from experimental thermodynamic integral free energy of mixing data using Complex formation model. The new method was first used to theoretically compute the γ∞s of 10 binary alloys whose γ∞s have been determined by experiments. The significant agreement between the computed values and the available experimental values served as impetus for applying the new method to 22 selected binary liquid alloys whose γ∞s are either nonexistent or incomplete. In order to verify the reliability of the computed γ∞s of the 22 selected alloys, we recomputed the γ∞s using three other existing methods of computing or estimating γ∞s and then used the γ∞s obtained from each of the four methods (the new method inclusive) to compute thermodynamic activities of components of each of the binary systems. The computed activities were compared with available experimental activities. It is observed that the results from the method being proposed, in most of the selected alloys, showed better agreement with experimental activity data. Thus, the new method is an alternative and in certain instances, more reliable approach of computing γ∞s of binary liquid alloys.

  7. Characterisation of the surface thermodynamic properties of cement components by inverse gas chromatography at infinite dilution

    SciTech Connect

    Perruchot, Christian; Chehimi, Mohamed M.; Vaulay, Marie-Josephe; Benzarti, Karim . E-mail: benzarti@lcpc.fr

    2006-02-15

    The surface thermodynamic properties of three main inorganic compounds formed during hydration of Portland cement: calcium hydroxide (Ca(OH){sub 2}), ettringite (3CaO.Al{sub 2}O{sub 3}.3CaSO{sub 4}.32H{sub 2}O) and calcium-silicate-hydrates (C-S-H), respectively, and one mineral filler: calcium carbonate (CaCO{sub 3}), have been characterised by inverse gas chromatography at infinite dilution (IGC-ID) at 35 deg. C. The thermodynamic properties have been investigated using a wide range of non-polar (n-alkane series), Lewis acidic (CH{sub 2}Cl{sub 2} and CHCl{sub 3}), Lewis basic (diethyl ether) and aromatic (benzene) and n-alkene series molecular probes, respectively. The tested samples are fairly high surface energy materials as judged by the high dispersive contribution to the total surface energy (the dispersive components {gamma} {sub s} {sup d} range from 45.6 up to 236.2 mJ m{sup -2} at 35 deg. C) and exhibit amphoteric properties, with a predominant acidic character. In the case of hydrated components (i.e. ettringite and C-S-H), the surface thermodynamic properties have been determined at various temperatures (from 35 up to 120 deg. C) in order to examine the influence of the water content. The changes of both dispersive and specific components clearly demonstrate that the material surface properties are activated with temperature. The changes in the acid-base properties are correlated with the extent of the overall water loss induced by the thermal treatment as demonstrated by thermogravimetric analysis (TGA). The elemental surface composition of these compounds has been determined by X-ray photoelectron spectroscopy (XPS)

  8. Measures of correlations in infinite-dimensional quantum systems

    NASA Astrophysics Data System (ADS)

    Shirokov, M. E.

    2016-05-01

    Several important measures of correlations of the state of a finite-dimensional composite quantum system are defined as linear combinations of marginal entropies of this state. This paper is devoted to infinite-dimensional generalizations of such quantities and to an analysis of their properties. We introduce the notion of faithful extension of a linear combination of marginal entropies and consider several concrete examples, the simplest of which are quantum mutual information and quantum conditional entropy. Then we show that quantum conditional mutual information can be defined uniquely as a lower semicontinuous function on the set of all states of a tripartite infinite-dimensional system possessing all the basic properties valid in finite dimensions. Infinite-dimensional generalizations of some other measures of correlations in multipartite quantum systems are also considered. Applications of the results to the theory of infinite-dimensional quantum channels and their capacities are considered. The existence of a Fawzi-Renner recovery channel reproducing marginal states for all tripartite states (including states with infinite marginal entropies) is shown. Bibliography: 47 titles.

  9. Activity coefficients at infinite dilution of organic compounds in 1-(meth)acryloyloxyalkyl-3-methylimidazolium bromide using inverse gas chromatography.

    PubMed

    Mutelet, Fabrice; Jaubert, Jean-Noël; Rogalski, Marek; Harmand, Julie; Sindt, Michèle; Mieloszynski, Jean-Luc

    2008-03-27

    Activity coefficients at infinite dilution, gammainfinity, of organic compounds in two new room-temperature ionic liquids (n-methacryloyloxyhexyl-N-methylimidazolium bromide (C10H17O2MIM)(Br) at 313.15 and 323.15 K and n-acryloyloxypropyl-N-methylimidazolium bromide(C6H11O2MIM)(Br)) were determined using inverse gas chromatography. Phase loading studies of the net retention volume per gram of packing as a function of the percent phase loading were used to estimate the influence of concurrent retention mechanisms on the accuracy of activity coefficients at infinite dilution of solutes in both ionic liquids. It was found that most of the solutes were retained largely by partition with a small contribution from adsorption and that n-alkanes were retained predominantly by interfacial adsorption on ionic liquids studied in this work. The solvation characteristics of the two ionic liquids were evaluated using the Abraham solvation parameter model. PMID:18318530

  10. Infinite dilution partial molar properties of aqueous solutions of nonelectrolytes. I. Equations for partial molar volumes at infinite dilution and standard thermodynamic functions of hydration of volatile nonelectrolytes over wide ranges of conditions

    NASA Astrophysics Data System (ADS)

    Plyasunov, Andrey V.; O'Connell, John P.; Wood, Robert H.

    2000-02-01

    A semitheoretical expression for partial molar volumes at infinite dilution of aqueous nonelectrolyte solutes has been developed employing the collection of properties from fluctuation solution theory for use over wide ranges of temperature and pressure. The form of the solution expression was suggested by a comparison of solute/solvent and solvent/solvent direct correlation function integrals (DCFI). The selection of solvent density and compressibility as model variables provides a correct description in the critical region while second virial coefficients have been used to give a rigorous expression in the low density region. The formulation has been integrated to obtain analytic expressions for thermodynamic properties of hydration at supercritical temperatures. The equation is limited to solutes for which B12 (the second cross virial coefficient between water and a solute molecule) is known or can be estimated. Regression of the three remaining parameters gives good correlations of the available experimental data. A strategy for estimating these parameters allows prediction from readily available data.

  11. Second quantisation for skew convolution products of infinitely divisible measures

    NASA Astrophysics Data System (ADS)

    Applebaum, David; van Neerven, Jan

    2015-03-01

    Suppose λ1 and λ2 are infinitely divisible Radon measures on real Banach spaces E1 and E2, respectively and let T : E1 → E2 be a Borel measurable mapping so that T(λ1) * ρ = λ2 for some Radon probability measure ρ on E2. Extending previous results for the Gaussian and the Poissonian case, we study the problem of representing the "transition operator" PT : Lp(E2, λ2) → Lp(E1, λ1) given by $PTf(x) = ∫ E{2}f(T(x) + y)dρ (y)$ as the second quantisation of a contraction operator acting between suitably chosen "reproducing kernel Hilbert spaces" associated with λ1 and λ2.

  12. Molecular dynamics simulation of diffusion coefficients and structural properties of some alkylbenzenes in supercritical carbon dioxide at infinite dilution

    SciTech Connect

    Wang, Jinyang; Zhong, Haimin; Qiu, Wenda; Chen, Liuping; Feng, Huajie

    2014-03-14

    The binary infinite dilute diffusion coefficients, D{sub 12}{sup ∞}, of some alkylbenzenes (Ph-C{sub n}, from Ph-H to Ph-C{sub 12}) from 313 K to 333 K at 15 MPa in supercritical carbon dioxide (scCO{sub 2}) have been studied by molecular dynamics (MD) simulation. The MD values agree well with the experimental ones, which indicate MD simulation technique is a powerful way to predict and obtain diffusion coefficients of solutes in supercritical fluids. Besides, the local structures of Ph-C{sub n}/CO{sub 2} fluids are further investigated by calculating radial distribution functions and coordination numbers. It qualitatively convinces that the first solvation shell of Ph-C{sub n} in scCO{sub 2} is significantly influenced by the structure of Ph-C{sub n} solute. Meanwhile, the mean end-to-end distance, the mean radius of gyration and dihedral angle distribution are calculated to gain an insight into the structural properties of Ph-C{sub n} in scCO{sub 2}. The abnormal trends of radial distribution functions and coordination numbers can be reasonably explained in term of molecular flexibility. Moreover, the computed results of dihedral angle clarify that flexibility of long-chain Ph-C{sub n} is the result of internal rotation of C-C single bond (σ{sub c-c}) in alkyl chain. It is interesting that compared with n-alkane, because of the existence of benzene ring, the flexibility of alkyl chain in Ph-C{sub n} with same carbon atom number is significantly reduced, as a result, the carbon chain dependence of diffusion behaviors for long-chain n-alkane (n ≥ 5) and long-chain Ph-C{sub n} (n ≥ 4) in scCO{sub 2} are different.

  13. Molecular dynamics simulation of diffusion coefficients and structural properties of some alkylbenzenes in supercritical carbon dioxide at infinite dilution.

    PubMed

    Wang, Jinyang; Zhong, Haimin; Feng, Huajie; Qiu, Wenda; Chen, Liuping

    2014-03-14

    The binary infinite dilute diffusion coefficients, D₁₂(∞), of some alkylbenzenes (Ph-C(n), from Ph-H to Ph-C12) from 313 K to 333 K at 15 MPa in supercritical carbon dioxide (scCO2) have been studied by molecular dynamics (MD) simulation. The MD values agree well with the experimental ones, which indicate MD simulation technique is a powerful way to predict and obtain diffusion coefficients of solutes in supercritical fluids. Besides, the local structures of Ph-C(n)/CO2 fluids are further investigated by calculating radial distribution functions and coordination numbers. It qualitatively convinces that the first solvation shell of Ph-C(n) in scCO2 is significantly influenced by the structure of Ph-C(n) solute. Meanwhile, the mean end-to-end distance, the mean radius of gyration and dihedral angle distribution are calculated to gain an insight into the structural properties of Ph-C(n) in scCO2. The abnormal trends of radial distribution functions and coordination numbers can be reasonably explained in term of molecular flexibility. Moreover, the computed results of dihedral angle clarify that flexibility of long-chain Ph-C(n) is the result of internal rotation of C-C single bond (σ(c-c)) in alkyl chain. It is interesting that compared with n-alkane, because of the existence of benzene ring, the flexibility of alkyl chain in Ph-C(n) with same carbon atom number is significantly reduced, as a result, the carbon chain dependence of diffusion behaviors for long-chain n-alkane (n ≥ 5) and long-chain Ph-C(n) (n ≥ 4) in scCO2 are different. PMID:24628176

  14. Activity Coefficients at Infinite Dilution of Organic Compounds in Trihexyl(tetradecyl)phophonium Bis(trifluoromethylsulfonyl)imide Using Inverse Gas Chromatography

    SciTech Connect

    Revelli, Anne-Laure; Sprunger, Laura; Gibbs, Jennifer; Acree, William; Baker, Gary A; Mutelet, Fabrice

    2009-01-01

    Activity coefficients at infinite dilution of organic compounds in the ionic liquid (IL) trihexyl(tetradecyl) phosphonium bis(trifluoromethylsulfonyl)imide were determined using inverse gas chromatography at three temperatures, T ) (302.45, 322.35, and 342.45) K. Linear free energy relationship (LFER) correlations have been obtained for describing the gas-to-IL and water-to-IL partition coefficients.

  15. Isotropic probability measures in infinite-dimensional spaces

    NASA Technical Reports Server (NTRS)

    Backus, George

    1987-01-01

    Let R be the real numbers, R(n) the linear space of all real n-tuples, and R(infinity) the linear space of all infinite real sequences x = (x sub 1, x sub 2,...). Let P sub in :R(infinity) approaches R(n) be the projection operator with P sub n (x) = (x sub 1,...,x sub n). Let p(infinity) be a probability measure on the smallest sigma-ring of subsets of R(infinity) which includes all of the cylinder sets P sub n(-1) (B sub n), where B sub n is an arbitrary Borel subset of R(n). Let p sub n be the marginal distribution of p(infinity) on R(n), so p sub n(B sub n) = p(infinity) (P sub n to the -1 (B sub n)) for each B sub n. A measure on R(n) is isotropic if it is invariant under all orthogonal transformations of R(n). All members of the set of all isotropic probability distributions on R(n) are described. The result calls into question both stochastic inversion and Bayesian inference, as currently used in many geophysical inverse problems.

  16. Correlation and prediction of thermodynamic properties of nonelectrolytes at infinite dilution in water over very wide temperature and pressure ranges (2000 K and 10 GPa)

    NASA Astrophysics Data System (ADS)

    Plyasunov, Andrey V.

    2015-11-01

    Thermodynamic modeling of natural processes involving deep aqueous fluids requires the knowledge of the values of chemical potentials (the Gibbs energy) of aqueous species. An accurate prediction of thermodynamic properties at high T and P is a strong challenge. It is shown that geochemical models, including the well-known HKF-model, cannot be recommended for an indiscriminate use at supercritical temperatures to predict chemical potentials of nonelectrolytes at infinite dilution in water. Nevertheless, sufficiently accurate predictions of ϕ2∞ (the fugacity coefficients at infinite dilution in water) of aqueous nonelectrolytes up to 2000 K and water densities up to 1500 kg m-3, i.e. pressure up to 10-12 GPa, can be made relying on known theoretical relations valid at various parts of the phase diagram of water. In essence, the method, proposed in this work, consists in the interpolation of properties between two known limits: the first one, at low water densities, is defined by the values of the second virial coefficients for water-solute interactions, and the second, at high water densities - by predictions of the theory of a mixture of hard spheres. The interpolation at moderate temperatures (700-1300 K) and water densities (500-900 kg m-3) is simplified by sufficiently accurate predictions of properties using a semiempirical variant of a corresponding-states principle. Presented examples of the prediction of fugacity coefficients of "gases" at infinite dilution in water and of an aqueous solubility of corundum over very wide ranges of water densities/pressures demonstrate the potential and generality of the proposed methods of evaluating the thermodynamic properties of aqueous neutral compounds.

  17. In Silico Calculation of Infinite Dilution Activity Coefficients of Molecular Solutes in Ionic Liquids: Critical Review of Current Methods and New Models Based on Three Machine Learning Algorithms.

    PubMed

    Paduszyński, Kamil

    2016-08-22

    The aim of the paper is to address all the disadvantages of currently available models for calculating infinite dilution activity coefficients (γ(∞)) of molecular solutes in ionic liquids (ILs)-a relevant property from the point of view of many applications of ILs, particularly in separations. Three new models are proposed, each of them based on distinct machine learning algorithm: stepwise multiple linear regression (SWMLR), feed-forward artificial neural network (FFANN), and least-squares support vector machine (LSSVM). The models were established based on the most comprehensive γ(∞) data bank reported so far (>34 000 data points for 188 ILs and 128 solutes). Following the paper published previously [J. Chem. Inf. Model 2014, 54, 1311-1324], the ILs were treated in terms of group contributions, whereas the Abraham solvation parameters were used to quantify an impact of solute structure. Temperature is also included in the input data of the models so that they can be utilized to obtain temperature-dependent data and thus related thermodynamic functions. Both internal and external validation techniques were applied to assess the statistical significance and explanatory power of the final correlations. A comparative study of the overall performance of the investigated SWMLR/FFANN/LSSVM approaches is presented in terms of root-mean-square error and average absolute relative deviation between calculated and experimental γ(∞), evaluated for different families of ILs and solutes, as well as between calculated and experimental infinite dilution selectivity for separation problems benzene from n-hexane and thiophene from n-heptane. LSSVM is shown to be a method with the lowest values of both training and generalization errors. It is finally demonstrated that the established models exhibit an improved accuracy compared to the state-of-the-art model, namely, temperature-dependent group contribution linear solvation energy relationship, published in 2011 [J. Chem

  18. Observed Measures and Fluctuations in Dissipative Infinite Ergodic Systems: Randomization Theory for the Infinite-Modal Maps with Ant-Lion Property

    NASA Astrophysics Data System (ADS)

    Nakagawa, Masaki; Aizawa, Yoji

    2014-10-01

    Universal aspects of a certain class of infinite ergodic systems are studied by using the infinite-modal maps with a special interest to their observed measures. It is shown that the ant-lion (AL) property is an important nature to realize the infinite ergodicity in the dissipative dynamics. The AL-property, which seems to be a little bit paradoxical one, is characterized by the monotonical relaxation of mean orbits into a singular stable point, but it causes the divergence of the Lyapunov exponent as well as the emergence of a number of absolutely-continuous invariant measures. Our main concern is to characterize the unique observed measure in those many admissible ergodic measures. To this end, firstly the randomization formulae are developed on the basis of the uniform distribution theorem by Weyl, to derive the stochastic aspects of the AL-property. Actually, it is shown that the statistical natures of the infinite-modal maps are well explained by the randomization formulae. Furthermore, it is shown that the observed measure derived from the randomization formulae is universal, and that the asymptotic form obeys the power law with the exponent -1, in agreement with numerical simulations.

  19. A remark on the infinite-volume Gibbs measures of spin glasses

    NASA Astrophysics Data System (ADS)

    Arguin, Louis-Pierre

    2008-12-01

    In this note, we point out that infinite-volume Gibbs measures of spin glass models on the hypercube can be identified as random probability measures on the unit ball of a Hilbert space. This simple observation follows from a result of Dovbysh and Sudakov on weakly exchangeable random matrices. Limiting Gibbs measures can then be studied as single well-defined objects. This approach naturally extends the space of random overlap structures as defined by Aizenman et al. We discuss the Ruelle probability cascades and the stochastic stability within this framework. As an application, we use an idea of Parisi and Talagrand to prove that if a sequence of finite-volume Gibbs measures satisfies the Ghirlanda-Guerra identities, then the infinite-volume measure must be singular as a measure on a Hilbert space.

  20. Sphere power measuring in ophthalmic lenses by infinite fringe moiré deflectometry

    NASA Astrophysics Data System (ADS)

    García-Ruelas, Jorge A.; Trujillo-Schiaffino, Gerardo; Salas-Peimbert, Didia P.; Anguiano-Morales, Marcelino; Corral-Martinez, Luis F.

    2013-11-01

    We present a method to measure spherical power in ophthalmic lenses based on the measurement of moiré patterns, using the technique called infinite fringe moiré deflectometry. We develop a theoretical model using a geometrical analysis that was validated by a computer simulation using the LabVIEW software; also we build an experimental setup in which we get experimental data. As results, we obtain a measurement of the spherical power of a set of ophthalmic test lenses in the range of +/- 0.50 to +/- 3.00 diopters. This power is obtained by measuring the separation between each fringe of moiré pattern, from the obtained data we analyze the theoretical model and we make the necessary corrections, using polynomial regression by the method of least squares, to comply with standard ISO8598. At the same time, some components of the experimental setup were being improved to facilitate its implementation and obtain better experimental data.

  1. Accuracy of dilution techniques for access flow measurement during hemodialysis.

    PubMed

    Krivitski, N M; MacGibbon, D; Gleed, R D; Dobson, A

    1998-03-01

    Access flow is now widely measured by creating artificial recirculation with the dialysis lines reversed and using dilution methods that sense either ultrasound velocity, electrical impedance, optical, or thermal changes. This study identifies and quantifies factors that influence the accuracy of access flow measurements and recommends ways to reduce these errors. Two major sources of access flow measurement error are identified, arising firstly from the second pass of the indicator by recirculation through the cardiopulmonary system (cardiopulmonary recirculation, CPR), and secondly from changes in venous line blood flow (Qb) and vascular access flow induced by the pressure of venous bolus injections. These errors are considered from theory, by direct measurement of access flow in a sheep model, and by analysis of clinical data. Two extremes for the venous introduction of indicator can be considered in access flow measurements, a slow infusion, which perturbs neither the venous line flow nor access flow but increases the error attributable to the second pass of the indicator by recirculation through cardiopulmonary system, or rapid injection, which eases separation of the second pass of the indicator signal but generates changes in the venous flow and access flow. If CPR is not eliminated, the area added to that of the first pass of indicator ranges up to 40%. Good time resolution could permit the separation of the areas generated by the first and second passage of the indicator. In sheep experiments, injections of 5 or 10 mL into a venous port close to the vascular access caused Qb to change by 20% to 40%. Both the animal experiments and analysis of raw data collected during routine clinical dialysis showed that moving the injection site sufficiently far from the patient, before or into the venous bubble trap, reduced the increase in Qb to only approximately 5% during the critical time when the concentration curve is changing for most tubing brands (Baxter, Belco

  2. Directly measuring mean and variance of infinite-spectrum observables such as the photon orbital angular momentum.

    PubMed

    Piccirillo, Bruno; Slussarenko, Sergei; Marrucci, Lorenzo; Santamato, Enrico

    2015-01-01

    The standard method for experimentally determining the probability distribution of an observable in quantum mechanics is the measurement of the observable spectrum. However, for infinite-dimensional degrees of freedom, this approach would require ideally infinite or, more realistically, a very large number of measurements. Here we consider an alternative method which can yield the mean and variance of an observable of an infinite-dimensional system by measuring only a two-dimensional pointer weakly coupled with the system. In our demonstrative implementation, we determine both the mean and the variance of the orbital angular momentum of a light beam without acquiring the entire spectrum, but measuring the Stokes parameters of the optical polarization (acting as pointer), after the beam has suffered a suitable spin-orbit weak interaction. This example can provide a paradigm for a new class of useful weak quantum measurements. PMID:26477715

  3. Directly measuring mean and variance of infinite-spectrum observables such as the photon orbital angular momentum

    NASA Astrophysics Data System (ADS)

    Piccirillo, Bruno; Slussarenko, Sergei; Marrucci, Lorenzo; Santamato, Enrico

    2015-10-01

    The standard method for experimentally determining the probability distribution of an observable in quantum mechanics is the measurement of the observable spectrum. However, for infinite-dimensional degrees of freedom, this approach would require ideally infinite or, more realistically, a very large number of measurements. Here we consider an alternative method which can yield the mean and variance of an observable of an infinite-dimensional system by measuring only a two-dimensional pointer weakly coupled with the system. In our demonstrative implementation, we determine both the mean and the variance of the orbital angular momentum of a light beam without acquiring the entire spectrum, but measuring the Stokes parameters of the optical polarization (acting as pointer), after the beam has suffered a suitable spin-orbit weak interaction. This example can provide a paradigm for a new class of useful weak quantum measurements.

  4. Directly measuring mean and variance of infinite-spectrum observables such as the photon orbital angular momentum

    PubMed Central

    Piccirillo, Bruno; Slussarenko, Sergei; Marrucci, Lorenzo; Santamato, Enrico

    2015-01-01

    The standard method for experimentally determining the probability distribution of an observable in quantum mechanics is the measurement of the observable spectrum. However, for infinite-dimensional degrees of freedom, this approach would require ideally infinite or, more realistically, a very large number of measurements. Here we consider an alternative method which can yield the mean and variance of an observable of an infinite-dimensional system by measuring only a two-dimensional pointer weakly coupled with the system. In our demonstrative implementation, we determine both the mean and the variance of the orbital angular momentum of a light beam without acquiring the entire spectrum, but measuring the Stokes parameters of the optical polarization (acting as pointer), after the beam has suffered a suitable spin–orbit weak interaction. This example can provide a paradigm for a new class of useful weak quantum measurements. PMID:26477715

  5. Infinite Multiplets

    DOE R&D Accomplishments Database

    Nambu, Y.

    1967-01-01

    The main ingredients of the method of infinite multiplets consist of: 1) the use of wave functions with an infinite number of components for describing an infinite tower of discrete states of an isolated system (such as an atom, a nucleus, or a hadron), 2) the use of group theory, instead of dynamical considerations, in determining the properties of the wave functions.

  6. Noninvasive photoacoustic measurement of the composite indicator dilution curve for cardiac output estimation

    PubMed Central

    Kang, DongYel; Huang, Qiaojian; Li, Youzhi

    2015-01-01

    Recently, the measurement of indicator dilution curves using a photoacoustic (PA) technology was reported, which showed promising results on the noninvasive estimation of cardiac output (CO) that is an important hemodynamic parameter useful in various clinical situations. However, in clinical practice, measuring PA indicator dilution curves from an arterial blood vessel requires an ultrasound transducer array capable of focusing on the targeted artery. This causes several challenges on the clinical translation of the PA indicator dilution method, such as high sensor cost and complexity. In this paper, we theoretically derived that a composite PA indicator dilution curve simultaneously measured from both arterial and venous blood vessels can be used to estimate CO correctly. The ex-vivo and in-vivo experimental results with a flat ultrasound transducer verified the developed theory. We believe this new concept would overcome the main challenges on the clinical translation of the noninvasive PA indicator dilution technology. PMID:25780743

  7. μ-PIV measurements of the ensemble flow fields surrounding a migrating semi-infinite bubble

    PubMed Central

    Yamaguchi, Eiichiro; Smith, Bradford J.; Gaver, Donald P.

    2012-01-01

    Microscale particle image velocimetry (μ-PIV) measurements of ensemble flow fields surrounding a steadily-migrating semi-infinite bubble through the novel adaptation of a computer controlled linear motor flow control system. The system was programmed to generate a square wave velocity input in order to produce accurate constant bubble propagation repeatedly and effectively through a fused glass capillary tube. We present a novel technique for re-positioning of the coordinate axis to the bubble tip frame of reference in each instantaneous field through the analysis of the sudden change of standard deviation of centerline velocity profiles across the bubble interface. Ensemble averages were then computed in this bubble tip frame of reference. Combined fluid systems of water/air, glycerol/air, and glycerol/Si-oil were used to investigate flows comparable to computational simulations described in Smith and Gaver (2008) and to past experimental observations of interfacial shape. Fluorescent particle images were also analyzed to measure the residual film thickness trailing behind the bubble. The flow fields and film thickness agree very well with the computational simulations as well as existing experimental and analytical results. Particle accumulation and migration associated with the flow patterns near the bubble tip after long experimental durations are discussed as potential sources of error in the experimental method. PMID:23049158

  8. Isotropic probability measures in infinite dimensional spaces: Inverse problems/prior information/stochastic inversion

    NASA Technical Reports Server (NTRS)

    Backus, George

    1987-01-01

    Let R be the real numbers, R(n) the linear space of all real n-tuples, and R(infinity) the linear space of all infinite real sequences x = (x sub 1, x sub 2,...). Let P sub n :R(infinity) approaches R(n) be the projection operator with P sub n (x) = (x sub 1,...,x sub n). Let p(infinity) be a probability measure on the smallest sigma-ring of subsets of R(infinity) which includes all of the cylinder sets P sub n(-1) (B sub n), where B sub n is an arbitrary Borel subset of R(n). Let p sub n be the marginal distribution of p(infinity) on R(n), so p sub n(B sub n) = p(infinity)(P sub n to the -1(B sub n)) for each B sub n. A measure on R(n) is isotropic if it is invariant under all orthogonal transformations of R(n). All members of the set of all isotropic probability distributions on R(n) are described. The result calls into question both stochastic inversion and Bayesian inference, as currently used in many geophysical inverse problems.

  9. Measurement of nonlinear parameters in a semi-infinite medium: laboratory experiment in a berea sandstone

    NASA Astrophysics Data System (ADS)

    Gallot, T.; Fehler, M. C.; Brown, S. R.; Buns, D.; Szabo, T.; Malcolm, A. E.

    2013-12-01

    The nonlinear mechanical behavior of rocks is a well known phenomenon at a laboratory scale and has been observed during earthquakes, slow slip events, volcanic activity, reservoir fracturing, etc. he present work explores the possibility of measuring nonlinear parameters in a semi-infinite medium. Contrary to existing methods that rely on vibrating a sample at a fixed resonant frequency, a pulsed wave is used to create a high amplitude perturbation (the pump) responsible for the nonlinear response. At the same time, a low amplitude wave probes the material to measure changes in elastic properties. Laboratory experiments have been performed in rocks (berea sandstones) to explore the possibility of using such a method for Earth imaging. The strain created by the pump (a shear wave in the tens of kHz), is on the order of a microstrain and is measured by laser vibrometry and extrapolated to the whole sample by a finite difference simulation. A compressional pulse (in the hundreds of kHz range) probes the 15-cm size sample. The variation in time of flight is related to a change in elasticity as described as a function of the strain through quadratic and cubic nonlinearities. Those nonlinear coefficients are shown to be sensitive to several environmental parameters such as temperature, humidity, and also physical properties such as the amplitude of the strain and the relative orientation of the pump and the probing wave. Experimental set-up: a P-wave transducer generates an ultrasonic pulse at 500 kHz recorded by an identical transducer after propagation through the sample. The medium is then perturbed with a S-wave transducer on the top of the sample at 50 kHz .

  10. Measuring the Soret coefficient of nanoparticles in a dilute suspension

    PubMed Central

    Zhao, Chao; Fu, Jinxin; Oztekin, Alparslan; Cheng, Xuanhong

    2014-01-01

    Thermophoresis is an efficient process for the manipulation of molecules and nanoparticles due to the strong force it generates on the nanoscale. Thermophoresis is characterized by the Soret coefficient. Conventionally, the Soret coefficient of nanosized species is obtained by fitting the concentration profile under a temperature gradient at the steady state to a continuous phase model. However, when the number density of the target is ultralow and the dispersed species cannot be treated as a continuous phase, the bulk concentration fluctuates spatially, preventing extraction of temperature-gradient induced concentration profile. The present work demonstrates a strategy to tackle this problem by superimposing snapshots of nanoparticle distribution. The resulting image is suitable for the extraction of the Soret coefficient through the conventional data fitting method. The strategy is first tested through a discrete phase model that illustrates the spatial fluctuation of the nanoparticle concentration in a dilute suspension in response to the temperature gradient. By superimposing snapshots of the stochastic distribution, a thermophoretic depletion profile with low standard error is constructed, indicative of the Soret coefficient. Next, confocal analysis of nanoparticle distribution in response to a temperature gradient is performed using polystyrene nanobeads down to 1e-5% (v/v). The experimental results also reveal that superimposing enhances the accuracy of extracted Soret coefficient. The critical particle number density in the superimposed image for predicting the Soret coefficient is hypothesized to depend on the spatial resolution of the image. This study also demonstrates that the discrete phase model is an effective tool to study particle migration under thermophoresis in the liquid phase. PMID:25221433

  11. Measuring the Soret coefficient of nanoparticles in a dilute suspension.

    PubMed

    Zhao, Chao; Fu, Jinxin; Oztekin, Alparslan; Cheng, Xuanhong

    2014-10-01

    Thermophoresis is an efficient process for the manipulation of molecules and nanoparticles due to the strong force it generates on the nanoscale. Thermophoresis is characterized by the Soret coefficient. Conventionally, the Soret coefficient of nanosized species is obtained by fitting the concentration profile under a temperature gradient at the steady state to a continuous phase model. However, when the number density of the target is ultralow and the dispersed species cannot be treated as a continuous phase, the bulk concentration fluctuates spatially, preventing extraction of temperature-gradient induced concentration profile. The present work demonstrates a strategy to tackle this problem by superimposing snapshots of nanoparticle distribution. The resulting image is suitable for the extraction of the Soret coefficient through the conventional data fitting method. The strategy is first tested through a discrete phase model that illustrates the spatial fluctuation of the nanoparticle concentration in a dilute suspension in response to the temperature gradient. By superimposing snapshots of the stochastic distribution, a thermophoretic depletion profile with low standard error is constructed, indicative of the Soret coefficient. Next, confocal analysis of nanoparticle distribution in response to a temperature gradient is performed using polystyrene nanobeads down to 1e-5% (v/v). The experimental results also reveal that superimposing enhances the accuracy of extracted Soret coefficient. The critical particle number density in the superimposed image for predicting the Soret coefficient is hypothesized to depend on the spatial resolution of the image. This study also demonstrates that the discrete phase model is an effective tool to study particle migration under thermophoresis in the liquid phase. PMID:25221433

  12. Thermal dilution measurement of cardiac output in dogs using an analog computer.

    PubMed

    Hendriks, F F; Schipperheyn, J J; Quanjer, P H

    1978-01-01

    Thermal dilution cardiac output determinations in dogs were compared to simultaneously performed Fick oxygen measurements. The purpose of this study was to validate in dog experiments a method for thermal dilution measurement which employs a double-thermistor catheter combined with an automatic computer as described by Olsson et al. Dilution and injectate temperature are entered directly into the calculation. The method does not employ logarithmic extrapolation, integration of the dilution signal being terminated when a preset cut-off level is reached. Errors due to recirculation, thermal capacitance of the right heart and heat exchange with the catheter's dead space require the use of an empirically derived correction factor, which in dogs was found to be significantly different from the factor used for human thermal dilution curves. With the appropriate cut-off level and correction factor a good agreement was found between the results of the thermal dilution and the Fick method. The regression equation for 47 experiments was found to be COtd = 0.95 COFick + 0.08; the correlation coefficient was 0.94. PMID:728031

  13. Cadmium fixation in soils measured by isotopic dilution

    SciTech Connect

    Smolders, E.; Brans, K.; Foeldi, A.; Merckx, R.

    1999-01-01

    There is conflicting evidence on the effect of time of contact between soil and Cd on Cd availability to plants. If Cd can be fixed in soil by aging, higher soil contamination may be tolerated. Fixation of Cd by soil can be studied by adding small quantities of {sup 109}Cd to the indigenous soil Cd. The ratio of {sup 109}Cd to indigenous Cd in soil extracts or in plants gives information on the lability of Cd in soil. This isotope exchange technique was used to measure the labile and fixed Cd fractions in 10 Belgian agricultural soils (Soils A--I) with both background and elevated Cd content. The isotopically exchangeable Cd pool (E value) was measured after equilibrating {sup 109}Cd spiked soil suspensions in CaCl{sub 2} 0.01 M for 7 d. The %E values (the E value relative to aqua regia soluble Cd) ranged from 62 to 90% in the eight soils where %E values could be detected. The plant labile Cd pool, relative to aqua regia soluble Cd (%L value) was measured from the specific activities in wheat (Triticum aestivum L.) seedlings grown for 16 to 21 d on soils spiked with {sup 109}Cd. The Cd %L value varied from 55 to 109% (mean: 82%) with five soils having a significant (P < 0.05) fixed Cd fraction. Varying the soil incubation procedure after soil spiking and before plant growth marginally affected the specific activity of Cd in plants. The %L values always exceeded the respective %E value between 1.05- and 1.4-fold. It is concluded that Cd fixation, where found, is not very pronounced.

  14. Comparison of infinite and wedge fringe settings in Mach Zehnder interferometer for temperature field measurement

    SciTech Connect

    Haridas, Divya; P, Vibin Antony; Sajith, V.; Sobhan, C. B.

    2014-10-15

    Interferometric method, which utilizes the interference of coherent light beams, is used to determine the temperature distribution in the vicinity of a vertical heater plate. The optical components are arranged so as to obtain wedge fringe and infinite fringe patterns and isotherms obtained in each case were compared. In wedge fringe setting, image processing techniques has been used for obtaining isotherms by digital subtraction of initial parallel fringe pattern from deformed fringe pattern. The experimental results obtained are compared with theoretical correlations. The merits and demerits of the fringe analysis techniques are discussed on the basis of the experimental results.

  15. Comparison of impedance cardiography and dye dilution method for measuring cardiac output

    PubMed Central

    Spiering, W; van Es, P N; de Leeuw, P W

    1998-01-01

    Objective—To assess the degree of agreement between impedance cardiography, using the NCCOM3-R7 device, and the gold standard—the dye dilution method—both under basal conditions and after stimulation of cardiac output.
Patients—35 paired measurements in five healthy male volunteers.
Interventions—To obtain higher levels of cardiac output, cardiac performance was stimulated with a dopamine infusion.
Results—In 35 paired measurements, the mean of all the impedance values was higher than that of the dye dilution values, at 10.2 v 7.4 l/min (p < 0.0001). The mean discrepancy between the two methods was 3.3 l/min, and the mean bias −2.9 l/min, with limits of agreement of −9.0 and 3.2 l/min. A change in cardiac output could not adequately be predicted by the NCCOM3-R7. In 20 of 25 measurements obtained during continuous intravenous dopamine infusions there was a rise in dye dilution cardiac output (range 0.2 to 5.9 l/min). Neither the magnitude nor the direction of the change in dye dilution values corresponded with the change measured by impedance cardiography. The mean discrepancy here between the two methods was 1.8 l/min, and the mean bias −0.8 l/min, with limits of agreement of −4.9 and 3.3 l/min.
Conclusions—In healthy volunteers, impedance cardiography with NCCOM3-R7 is inadequate for assessing cardiac output when compared with the dye dilution method.

 Keywords: cardiac output;  impedance cardiography;  dye dilution PMID:9659188

  16. Measurement of LNAPL flux using single-well intermittent mixing tracer dilution tests.

    PubMed

    Smith, Tim; Sale, Tom; Lyverse, Mark

    2012-01-01

    The stability of subsurface Light Nonaqueous Phase Liquids (LNAPLs) is a key factor driving expectations for remedial measures at LNAPL sites. The conventional approach to resolving LNAPL stability has been to apply Darcy's Equation. This paper explores an alternative approach wherein single-well tracer dilution tests with intermittent mixing are used to resolve LNAPL stability. As a first step, an implicit solution for single-well intermittent mixing tracer dilution tests is derived. This includes key assumptions and limits on the allowable time between intermittent mixing events. Second, single-well tracer dilution tests with intermittent mixing are conducted under conditions of known LNAPL flux. This includes a laboratory sand tank study and two field tests at active LNAPL recovery wells. Results from the sand tank studies indicate that LNAPL fluxes in wells can be transformed into formation fluxes using corrections for (1) LNAPL thicknesses in the well and formation and (2) convergence of flow to the well. Using the apparent convergence factor from the sand tank experiment, the average error between the known and measured LNAPL fluxes is 4%. Results from the field studies show nearly identical known and measured LNAPL fluxes at one well. At the second well the measured fluxes appear to exceed the known value by a factor of two. Agreement between the known and measured LNAPL fluxes, within a factor of two, indicates that single-well tracer dilution tests with intermittent mixing can be a viable means of resolving LNAPL stability. PMID:22489832

  17. Dramatic role of fragility in determining the magnitude of Tg perturbations to ultrathin film layers and near-infinitely dilute blend components

    NASA Astrophysics Data System (ADS)

    Evans, Christopher; Torkelson, John; Northwestern University Team

    2013-03-01

    Using fluorescence, we measure the glass transition temperatures (Tg) of ultrathin (11-14 nm) polystyrene (PS, bulk Tg = 103 °C) layers which can be tuned over ~ 80 °C when sandwiched between two bulk neighboring layers of poly(4-vinyl pyridine) (P4VP), polycarbonate, poly(vinyl chloride) (PVC) or poly(tert-butyl acrylate). Between P4VP, an ultrathin PS layer has its dynamics slaved and reports the Tg of bulk P4VP. In contrast, an ultrathin PS layer is weakly perturbed (Tg = 97 °C) when placed between PVC. These perturbations to the PS Tg become evident even for layers 10s of nanometers in thickness. Additionally, binary blends were prepared with 0.1 wt% PS components surrounded by the same neighboring polymers as in the trilayers. The Tg reported by an ultrathin PS layer and a 0.1 wt% PS blend component are the same for a given polymer pair indicating that the Tg perturbations in these two systems arise from a common physical origin. The strength of perturbations to PS correlate with the fragility of the neighboring domain in both blends and multilayers indicating that it is a key variable in determining the strength of Tg-confinement effects. Fragility also tracks with the magnitude of Tg-confinement effects observed in single layer polymer films supported on silicon wafers.

  18. In Situ Local Fracture Flow Measurement by the Double Packer Dilution Test

    NASA Astrophysics Data System (ADS)

    Englert, A.; Le Borgne, T.; Bour, O.; Klepikova, M.; Lavenant, N.

    2011-12-01

    For prediction of flow and transport in fractured media, prior estimation of the fracture network is essential, but challenging. Recent developments in hydraulic tomography have shown promising results for understanding connectivities between boreholes. However, as the hydraulic tomographic survey is typically based on the propagation of head only, it becomes a strongly non unique problem. To reduce the non uniqueness of tomographic surveys point conditioning has been found beneficial. Just as well, measurement of local flow in a fracture can serve as point conditioning for hydraulic and tracer tomographic surveys. Nevertheless, only few measurements of local fracture flow have been performed since this type of measurements implies several important technical issues. Dilution test in a packed off interval is a possible method for measuring fracture flow (e.g. Drost et al. 1968, Novakowski et al., 2005). However, a key issue for estimating flow with dilution tests is to ensure a full mixing of the tracer in the packed interval. This is typically done by including a mixing system within the packer. The design of such system can be challenging for deep wells and small diameters. Here, we propose a method where mixing is ensured by a recirculation loop including a surface tank. This method is adapted from the design proposed by Brouyere et al. (2008), who measured dilution in open wells. Dilution is quantified by measuring the concentration in the surface barrel as function of time. Together with the measurement of the circulating flow and the water filled volume in the surface barrel, the measured tracer dilution allows for calculation of the fracture flow. Since the method can be applied using a classical double packer system, it may provide a broader application of local flow measurements in heterogeneous media. We tested the approach on the Ploemeur fractured crystalline rock site. A one meter interval at depth 80 m with a single flowing fracture was isolated with

  19. Pleural liquid clearance rate measured in awake sheep by the volume of dilution method

    SciTech Connect

    Broaddus, V.C.; Wiener-Kronish, J.P.; Berthiaume, Y.; Staub, N.C.

    1986-03-01

    The authors reported 24h clearance of mock pleural effusions measured terminally in sheep. To measure effusion volume at different times in the same sheep, they injected /sup 111/In-transferrin and measured its dilution. In 5 sheep with effusions of known sizes, the method was accurate to +/-10%. In 5 awake sheep, the authors injected 10 ml/kg of a 1% protein solution via a non-penetrating rib capsule. At 6h, the authors measured the volume by the dilution method and at 24h by direct recovery. The clearance rate in each animal was constant at 2.9-6.0%/h (average 4.8 +/- 1.3%/h). This new method gives a reliable two point clearance rate and requires fewer animals.

  20. Evaluation of the Boron Dilution Method for Moderator Temperature Coefficient Measurements

    SciTech Connect

    Demaziere, Christophe; Pazsit, Imre; Por, Gabor

    2002-11-15

    A measurement of the at-power moderator temperature coefficient (MTC) at the pressurized water reactor Unit 4 of the Ringhals Nuclear Power Plant (Sweden) during fuel cycle 16 is analyzed. The measurement was performed when the boron concentration decreased under 300 ppm in the reactor coolant system, by using the boron dilution method. Detailed calculations were made to estimate all reactivity effects taking place during such a measurement. These effects can only be accounted for through static core calculations that allow calculating contributions to the reactivity change induced by the moderator temperature change. All the calculations were performed with the Studsvik Scandpower SIMULATE-3 code. Analysis of the measurement showed that the contribution of the Doppler effect (in the fuel) was almost negligible, whereas the reactivity effects due to other than the Doppler fuel coefficient and the boron change were surprisingly significant. It was concluded that due to the experimental inaccuracies, the uncertainty associated with the boron dilution method could be much larger than previously expected. The MTC might then be close to -72 pcm/degC, whereas the main goal of the measurement is to verify that the MTC is larger (less negative) than this threshold. The usefulness of the boron dilution method for MTC measurements can therefore be questioned.

  1. iFit and Light Dilution: Ultraviolet volcanic SO2 measurements under the microscope

    NASA Astrophysics Data System (ADS)

    Burton, Michael; Sawyer, Georgina

    2013-04-01

    Volcanic SO2 flux measurement systems are a staple of volcano monitoring networks, as this volcanic gas flux reflects the magma input rate into the volcano's feeding system. SO2 flux monitoring has been used since the seventies, with some notable successes at Pinatubo, Mt. St. Helens, Montserrat and Italian volcanoes. However, there are some subtle aspects of the atmospheric radiative transfer processed inherent in the technique which have been ignored for many years; or perhaps better, they have been forgotten, as these subtleties were clearly spelt out in early COSPEC papers by Millán and co-workers. Recent work by Kern et al. (2010, 2012) has re-focussed attention on the light dilution effect during SO2 plume measurements. This occurs when solar radiation is scattered into the slant column observed by a UV spectrometer or imaging system below the height of the volcanic plume, such that it has not passed through the plume. This below-plume light dilutes the SO2 absorption produced by light passing through the plume from above, apparently reducing the amount of SO2 present. Fortunately, the light dilution process leaves a signature in the shape of the SO2 absorption spectrum, due to the non-linear behaviour of absorption lines with respect to gas amount, following the Beer-Lamber law. This signature can be used to quantify the magnitude of the light dilution in real field spectra. We developed a new intensity spectrum UV fitting code called iFit that allows fitting of the light dilution signature, and applied this to examples from Stromboli and Etna. here we summarise the results from these studies and highlight the importance of this previously ignored process for quantify SO2 gas emissions from volcanoes.

  2. Global NOx Measurements in Turbulent Nitrogen-Diluted Hydrogen Jet Flames

    SciTech Connect

    Weiland, N.T.; Strakey, P.A.

    2007-03-01

    Turbulent hydrogen diffusion flames diluted with nitrogen are currently being studied to assess their ability to achieve the DOE Turbine Program’s aggressive emissions goal of 2 ppm NOx in a hydrogen-fueled IGCC gas turbine combustor. Since the unstrained adiabatic flame temperatures of these diluted flames are not low enough to eliminate thermal NOx formation the focus of the current work is to study how the effects of flame residence time and global flame strain can be used to help achieve the stated NOx emissions goal. Dry NOx measurements are presented as a function of jet diameter nitrogen dilution and jet velocity for a turbulent hydrogen/nitrogen jet issuing from a thin-lipped tube in an atmospheric pressure combustor. The NOx emission indices from these experiments are normalized by the flame residence time to ascertain the effects of global flame strain and fuel Lewis Number on the NOx emissions. In addition dilute hydrogen diffusion flame experiments were performed in a high-pressure combustor at 2 4 and 8 atm. The NOx emission data from these experiments are discussed as well as the results from a Computational Fluid Dynamics modeling effort currently underway to help explain the experimental data.

  3. Structure of Finite-RSB Asymptotic Gibbs Measures in the Diluted Spin Glass Models

    NASA Astrophysics Data System (ADS)

    Panchenko, Dmitry

    2016-01-01

    We suggest a possible approach to proving the Mézard-Parisi formula for the free energy in the diluted spin glass models, such as diluted K-spin or random K-sat model at any positive temperature. In the main contribution of the paper, we show that a certain small modification of the Hamiltonian in any of these models forces all finite-RSB asymptotic Gibbs measures in the sense of the overlaps to satisfy the Mézard-Parisi ansatz for the distribution of spins. Unfortunately, what is still missing is a description of the general full-RSB asymptotic Gibbs measures. If one could show that the general case can be approximated by finite-RSB case in the right sense then one could a posteriori remove the small modification of the Hamiltonian to recover the Mézard-Parisi formula for the original model.

  4. Short course on St-02 applications of isotope dilutions and isotopic measurements

    SciTech Connect

    Miller, P.

    1998-01-05

    This short course includes information on these topics and subtopics: (I) Nuclear Properties: (A) Historic roots; (B) Nomenclature; (C) Nuclear Stability and abundance; (D) Uses of isotopic techniques; (II) Instrumentation: (A) Sources; (B) Mass resolving elements; (C) Detectors; (III) Making Isotopic Measurements by ICP-MS: (A) Deadtime Correction; (B) Mass Discrimination; (C) Signal /Noise considerations; (IV) Applications and examples: (A) Isotope dilution; (B) Double Spike; (C) Biological Application; (D) Environmental Application; (E) Geological.

  5. On Infinite-Volume Mixing

    NASA Astrophysics Data System (ADS)

    Lenci, Marco

    2010-09-01

    In the context of the long-standing issue of mixing in infinite ergodic theory, we introduce the idea of mixing for observables possessing an infinite-volume average. The idea is borrowed from statistical mechanics and appears to be relevant, at least for extended systems with a direct physical interpretation. We discuss the pros and cons of a few mathematical definitions that can be devised, testing them on a prototypical class of infinite measure-preserving dynamical systems, namely, the random walks.

  6. A Dissimilarity Measure for Clustering High- and Infinite Dimensional Data that Satisfies the Triangle Inequality

    NASA Technical Reports Server (NTRS)

    Socolovsky, Eduardo A.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    The cosine or correlation measures of similarity used to cluster high dimensional data are interpreted as projections, and the orthogonal components are used to define a complementary dissimilarity measure to form a similarity-dissimilarity measure pair. Using a geometrical approach, a number of properties of this pair is established. This approach is also extended to general inner-product spaces of any dimension. These properties include the triangle inequality for the defined dissimilarity measure, error estimates for the triangle inequality and bounds on both measures that can be obtained with a few floating-point operations from previously computed values of the measures. The bounds and error estimates for the similarity and dissimilarity measures can be used to reduce the computational complexity of clustering algorithms and enhance their scalability, and the triangle inequality allows the design of clustering algorithms for high dimensional distributed data.

  7. Three-terminal capacitance cell for stopped-flow measurements of very dilute solutions

    NASA Astrophysics Data System (ADS)

    Tjahjono, Martin; Davis, Thomas; Garland, Marc

    2007-02-01

    A capacitance cell has been designed, constructed, and tested for stopped-flow measurements of very dilute low-relative permittivity liquid solutions. The capacitance cell utilizes a three-terminal design and is connected to ultrahigh sensitivity capacitance bridge. The cell was designed for operating conditions T ≈243.15-373.15K and P ≈0-1MPa and tested with pure anhydrous cyclohexane and with dilute acetone/cyclohexane solutions at 298.15K and 0.1MPa under an argon blanket in a thermostated bath with a temperature variation of <0.001K. Details of the design and materials of construction are reported. The measured relative permittivity of cyclohexane was 2.015 565, in agreement with the literature, and the long term variation of the measurement was ±5×10-6. The relative permittivities of the acetone/cyclohexane solutions were very linear (R2=0.9997) in the measured interval of 0.001-0.008mole fraction. These measurements confirm that the design specifications for stability and resolution/sensitivity of better than 1×10-5 have been realized. Finally, the present online capacitance cell was connected online to an ultrasensitive densitometer and ultrasensitive refractometer and binary acetone/cyclohexane solutions were measured. The measurements of density, refractive index, and relative permittivity were combined to provide a dipole moment of acetone of 2.750±0.005D, which is in good agreement with literature.

  8. Measurement of phloem transport rates by an indicator-dilution technique. [Triticum aestivum L

    SciTech Connect

    Fisher, D.B. )

    1990-10-01

    An indicator-dilution technique for the measurement of flow rates, commonly used by animal physiologists for circulation measurements, was adapted to the measurement of phloem translocation rates in the wheat (Triticum aestivum L.) peduncle. The approach is based on the observation that, during the transport of a given amount of solute, its mean concentration will be inversely proportional to flow rate. For phloem transport in the wheat peduncle, the necessary measurements are (a) the time course of tracer kinetics in the peduncle phloem, (b)the volume of sieve tubes and companion cells in the monitored segment of the peduncle, and (c) the amount of tracer transported past that point. The method was evaluated by in situ monitoring of {sup 32}PO{sub 4} transport in pulse-labeling experiments. Specific activities (i.e. {sup 32}P concentrations) of phloem exudate were in good agreement with those calculated from in situ count rates and measured phloem areas. Mass transport rates, calculated from volume flow rates and phloem exudate dry matter content, also agreed well with expected mass transport rates based on measurements of grain growth rate and net CO{sub 2} exchange by the ear. The indicator-dilution technique appears to offer good precision and accuracy for short-term measurements of phloem transport rates in the wheat peduncle and should be useful for other systems as well.

  9. Automated measurement of respiratory gas exchange by an inert gas dilution technique

    NASA Technical Reports Server (NTRS)

    Sawin, C. F.; Rummel, J. A.; Michel, E. L.

    1974-01-01

    A respiratory gas analyzer (RGA) has been developed wherein a mass spectrometer is the sole transducer required for measurement of respiratory gas exchange. The mass spectrometer maintains all signals in absolute phase relationships, precluding the need to synchronize flow and gas composition as required in other systems. The RGA system was evaluated by comparison with the Douglas bag technique. The RGA system established the feasibility of the inert gas dilution method for measuring breath-by-breath respiratory gas exchange. This breath-by-breath analytical capability permits detailed study of transient respiratory responses to exercise.

  10. The measurement of water vapor permeability of glove materials using dilute tritiated water

    NASA Astrophysics Data System (ADS)

    Doughty, D. H.

    As fusion technology progresses, there will be an increasing need to handle tritium and tritiated compounds. Protective clothing, especially drybox gloves, must be an effective barrier to minimize worker exposure. The water vapor permeability of glove materials and finished glove constructions is a crucial property of drybox gloves and is not sufficiently well characterized. We have built an apparatus that measures water vapor permeability of elastomers using dilute tritiated water. The technique is more sensitive than other methods currently available and allows us to make measurements on materials and under conditions previously inaccessible. In particular, we present results on laminated drybox gloves for which data is not currently available.

  11. Tracer dilution measurements for two-phase geothermal production: Comparative testing and operating experience

    SciTech Connect

    Hirtz, P.; Lovekin, J.

    1995-12-31

    The tracer dilution technique for the measurement of steam and water mass flowrates and total enthalpy of two-phase geothermal fluids has been in routine use in the U.S.A. for almost three years. The tracer technique was first tested and adopted on a field-wide basis at the Coso geothermal field in California. Validation of the method was performed at the Roosevelt Hot Springs geothermal project in Utah and the Salton Sea and Heber geothermal projects in California by direct comparison to orifice-plate flowmeter measurements of the separated phases. Production well mass flowrates and total enthalpy are now regularly measured by this technique in the Coso, Salton Sea and Heber geothermal fields. Implementation of the tracer method is currently underway for the Tiwi and Bulalo geothermal fields in the Philippines. This paper presents the conceptual design of the measurement process, the results of field validations, and operating experience during field-wide testing in Coso.

  12. Localization of an absorber in a turbid semi-infinite medium by spatially resolved continuous-wave diffuse reflectance measurements

    NASA Astrophysics Data System (ADS)

    Aksel, Ertugrul Burtecin; Turkoglu, Ahu Nur; Ercan, Ayse Ece; Akin, Ata

    2011-08-01

    A method to locate an absorber embedded in a semi-infinite turbid medium by spatially-resolved continuous-wave (SRCW) diffuse reflectance measurements is introduced. The depth of the absorber is assessed by single wavelength SRCW diffuse reflectance measurements by two detectors in a radial row. The ratio of perturbations introduced by the defect at two detectors is used to be matched with the ratio-versus-depth curve, which are generated by approximate formulas of continuous wave diffuse reflectance. The error due to approximation and the error in depth assessment are studied for different cases revealing favorable source-detector placements with respect to planar position of the defect. The effect of lateral displacement of the source with respect to defect is studied. A strategy to overcome errors introduced by erroneous prediction of background medium optical properties is suggested. Theoretical results indicate that the depth of the absorber can be obtained with 0.1 mm precision independent of its absorption coefficient and its size for the values chosen in the study. The approach is tested experimentally and it is observed that theoretical results fit with experimental data.

  13. Atmospheric dispersion modeling to assess the tracer dilution method for measuring landfill methane emissions

    NASA Astrophysics Data System (ADS)

    Taylor, D.; Delkash, M.; Chow, F. K.; Imhoff, P. T.

    2014-12-01

    Landfill methane emissions are difficult to estimate due to limited observation and uncertainty of the data. The tracer dilution method is a widely used approach that uses a tracer gas released at a known rate from one or more point sources, and the ratio of the concentration of tracer gas to concentration of methane measured at a downwind point is used to calculate the methane emissions rate. Here we use a high-resolution atmospheric model to examine the set-up of the tracer dilution method and its effects on the accuracy of methane emissions calculations. This method relies on optimal weather conditions and is limited by availability of locations where downwind measurements can be taken. Therefore using limited measurements taken with this method to estimate annual landfill emissions will yield totals of dubious accuracy. The Weather Research and Forecasting model (WRF) is a mesoscale meteorological model that is commonly used for atmospheric research as well as operational forecasts. Here, a scalar tracking subroutine is added to WRF to simulate the methane emissions from the surface of the landfill and the tracer gas from point sources. Using this model, many different tracer release configurations (number and placement of tracer release points and downwind measurement locations) are simulated and compared. Wind speed dependence of methane emissions is examined by prescribing surface flux as a function of local wind speed. The tracer dilution method can only collect landfill emissions data during ideal weather conditions, so modeling emissions during non-ideal conditions will give a better idea of how to predict total annual emissions taking into account the emissions on days when emissions cannot accurately be measured. The WRF output is compared to output of an analogous model adapted from the existing atmospheric model Advanced Regional Prediction System (ARPS) and to observation data from Sandtown Landfill in Delaware, USA. Future work includes adding

  14. Measurement of the body composition of living gray seals by hydrogen isotope dilution

    SciTech Connect

    Reilly, J.J.; Fedak, M.A. )

    1990-09-01

    The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a two-step model that involves measurement of total body water (TBW) by {sup 2}H or {sup 3}H dilution and application of predictive relationships between body components and TBW that were derived empirically by slaughter chemical analysis. TBW was overestimated by both {sup 2}HHO and {sup 3}HHO dilution; mean overestimates were 2.8 +/- 0.9% (SE) with 2H and 4.0 +/- 0.6% with {sup 3}H. The relationships for prediction of total body fat (TBF), protein (TBP), gross energy (TBGE), and ash (TBA) were as follows: %TBF = 105.1 - 1.47 (%TBW); %TBP = 0.42 (%TBW) - 4.75; TBGE (MJ) = 40.8 (mass in kg) - 48.5 (TBW in kg) - 0.4; and TBA (kg) = 0.1 - 0.008 (mass in kg) + 0.05 (TBW in kg). These relationships are applicable to gray seals of both sexes over a wide range of age and body conditions, and they predict the body composition of gray seals more accurately than the predictive equations derived from ringed seals (Pusa hispida) and from the equation of Pace and Rathbun, which has been reported to be generally applicable to mammals.

  15. Fluorescence dilution technique for measurement of albumin reflection coefficient in isolated glomeruli.

    PubMed

    Fan, Fan; Chen, Chun Cheng Andy; Zhang, Jin; Schreck, Carlos M N; Roman, Eric A; Williams, Jan M; Hirata, Takashi; Sharma, Mukut; Beard, Daniel A; Savin, Virginia J; Roman, Richard J

    2015-12-15

    This study describes a high-throughput fluorescence dilution technique to measure the albumin reflection coefficient (σAlb) of isolated glomeruli. Rats were injected with FITC-dextran 250 (75 mg/kg), and the glomeruli were isolated in a 6% BSA solution. Changes in the fluorescence of the glomerulus due to water influx in response to an imposed oncotic gradient was used to determine σAlb. Adjustment of the albumin concentration of the bath from 6 to 5, 4, 3, and 2% produced a 10, 25, 35, and 50% decrease in the fluorescence of the glomeruli. Pretreatment of glomeruli with protamine sulfate (2 mg/ml) or TGF-β1 (10 ng/ml) decreased σAlb from 1 to 0.54 and 0.48, respectively. Water and solute movement were modeled using Kedem-Katchalsky equations, and the measured responses closely fit the predicted behavior, indicating that loss of albumin by solvent drag or diffusion is negligible compared with the movement of water. We also found that σAlb was reduced by 17% in fawn hooded hypertensive rats, 33% in hypertensive Dahl salt-sensitive (SS) rats, 26% in streptozotocin-treated diabetic Dahl SS rats, and 21% in 6-mo old type II diabetic nephropathy rats relative to control Sprague-Dawley rats. The changes in glomerular permeability to albumin were correlated with the degree of proteinuria in these strains. These findings indicate that the fluorescence dilution technique can be used to measure σAlb in populations of isolated glomeruli and provides a means to assess the development of glomerular injury in hypertensive and diabetic models. PMID:26447220

  16. A stable isotope dilution method for measuring bioavailability of organic contaminants

    PubMed Central

    Delgado-Moreno, Laura; Gan, Jay

    2014-01-01

    Methods for determining bioavailability of organic contaminants suffer various operational limitations. We explored the use of stable isotope labeled references in developing an isotope dilution method (IDM) to measure the exchangeable pool (E) of pyrene and bifenthrin as an approximation of their bioavailability in sediments. The exchange of deuterated bifenthrin or pyrene with its native counterpart was completed within 48 h. The derived E was 38–82% for pyrene and 28–59% for bifenthrin. Regression between E and the sum of rapid and slow desorption fractions obtained from sequential desorption showed a slope close to 1.0. The ability of IDM to predict bioavailability was further shown from a strong relationship (r2 > 0.93) between E and bioaccumulation into Chironomus tentans. Given the abundance of stable isotope labeled references and their relatively easy analysis, the IDM has the potential to become a readily adoptable tool for estimating organic contaminants bioaccessibility in various matrices. PMID:23434573

  17. In Vivo Measurements Of Coronary Blood Volumi By Dye And Inert Gas Dilution Technic

    NASA Astrophysics Data System (ADS)

    Hoeft, A.; Korb, H.; Wolpers, H. G.

    1984-10-01

    The application of a double fiberoptic device for measurements of arterial and coronary venous dye dilution curves facilitates the determination of coronary mean transit times even under clinical conditions. Since the dye, indocyanine green, is an intravascular tracer, the calculation of tissue blood flow would be possible if the intracoronary blood volume per unit of muscular weight is known. This study was therefore designed to investigate the physiologic range and the influence of coronary vasodilation and different hemodynamic conditions on the amount of myocardial blood volume. All experiments were carried out on anaesthetized close chest mongrel dogs in heart catheterization technic. Myocardial preload, afterload and inotropism and coronary vascular tone were varied by induction of hypo-, normo- and hypervolemia as well as by intravenous application of catecholamines, 13-blocking agents and vasodilating drugs. The determination of coronary blood volume was based on arterial and coronary venous kinetics of the intravascular tracer indocyanine green and the freely diffusible tracers helium and argon. Simultaneous measurements of the dye and the inert gases were obtained by a double fiberoptic system and a twin mass spectrometer, respectively. The intravascular and the tissue mean transit times as well as the coronary blood volume per unit of tissue weight were computed from the impulse response functions obtained by numerical deconvolution of the arterial and coronary venous indicator dilution curves. In contrast to reports of other authors coronary blood volume did not increase to a major extend during coronary vasodilation or elevated afterload. These new results suggest that the variation of coronary blood volume described in the literature is mainly due to methodological errors resulting from monoexponential extrapolation and distortion of the dye signal by the sampling catheter. These systematic errors, which, in particular, lead to an overestimation of

  18. Soot surface temperature measurements in pure and diluted flames at atmospheric and elevated pressures

    SciTech Connect

    Berry Yelverton, T.L.; Roberts, W.L.

    2008-10-15

    Soot surface temperature was measured in laminar jet diffusion flames at atmospheric and elevated pressures. The soot surface temperature was measured in flames at one, two, four, and eight atmospheres with both pure and diluted (using helium, argon, nitrogen, or carbon dioxide individually) ethylene fuels with a calibrated two-color soot pyrometry technique. These two dimensional temperature profiles of the soot aid in the analysis and understanding of soot production, leading to possible methods for reducing soot emission. Each flame investigated was at its smoke point, i.e., at the fuel flow rate where the overall soot production and oxidation rates are equal. The smoke point was chosen because it was desirable to have similar soot loadings for each flame. A second set of measurements were also taken where the fuel flow rate was held constant to compare with earlier work. These measurements show that overall flame temperature decreases with increasing pressure, with increasing pressure the position of peak temperature shifts to the tip of the flame, and the temperatures measured were approximately 10% lower than those calculated assuming equilibrium and neglecting radiation. (author)

  19. Image-based correction of the light dilution effect for SO2 camera measurements

    NASA Astrophysics Data System (ADS)

    Campion, Robin; Delgado-Granados, Hugo; Mori, Toshiya

    2015-07-01

    Ultraviolet SO2 cameras are increasingly used in volcanology because of their ability to remotely measure the 2D distribution of SO2 in volcanic plumes, at a high frequency. However, light dilution, i.e., the scattering of ambient photons within the instrument's field of view (FoV) on air parcels located between the plume and the instrument, induces a systematic underestimation of the measurements, whose magnitude increases with distance, SO2 content, atmospheric pressure and turbidity. Here we describe a robust and straightforward method to quantify and correct this effect. We retrieve atmospheric scattering coefficients based on the contrast attenuation between the sky and the increasingly distant slope of the volcanic edifice. We illustrate our method with a case study at Etna volcano, where difference between corrected and uncorrected emission rates amounts to 40% to 80%, and investigate the temporal variations of the scattering coefficient during 1 h of measurements on Etna. We validate the correction method at Popocatépetl volcano by performing measurements of the same plume at different distances from the volcano. Finally, we reported the atmospheric scattering coefficients for several volcanoes at different latitudes and altitudes.

  20. Validity of deuterium oxide dilution for the measurement of body fat among Singaporeans.

    PubMed

    Deurenberg-Yap, Mabel; Deurenberg, Paul

    2002-09-01

    Body fat percent (BF%) was measured in 108 adult Chinese, 76 Malays, and 107 Indians in Singapore by densitometry, deuterium oxide dilution (hydrometry), dual energy x-ray absorptiometry (DXA) and a chemical four-compartment model (BF%4c). The hydration of the fat-free mass (FFM) was calculated. Subjects ranged in age from 18 to 69 years and their body mass index ranged from 16 to 40 kg/m2. BF%4c for the various subgroups were: Chinese females (33.5 +/- 7.5%), Chinese males (24.4 +/- 6.1%), Malay females (37.8 +/- 6.3%), Malay males (26.0 +/- 7.6%), Indian females (38.2 +/- 7.0%) and Indian males (28.1 +/- 5.5%). Biases were found between BF%4c and BF% measured by 2-compartment models (hydrometry, densitometry, DXA), with systematic underestimation by DXA and densitometry. On a group level hydrometry had the lowest bias while DXA gave the highest bias. When validated against BF%4c, 2-compartment models were found to be unsuitable for accurate measures of body fat due to high biases at the individual level and the violation of assumptions of constant hydration of FFM and density FFM among the ethnic groups. On a group level the best 2-compartment model for measuring body fat was found to be hydrometry. PMID:12362808

  1. Investigation of electrolyte measurement in diluted whole blood using spectroscopic and chemometric methods

    NASA Technical Reports Server (NTRS)

    Soller, Babs R.; Favreau, Janice; Idwasi, Patrick O.

    2003-01-01

    The feasibility of using near-infrared (NIR) spectroscopy in combination with partial least-squares (PLS) regression was explored to measure electrolyte concentration in whole blood samples. Spectra were collected from diluted blood samples containing randomized, clinically relevant concentrations of Na+, K+, and Ca2+. Sodium was also studied in lysed blood. Reference measurements were made from the same samples using a standard clinical chemistry instrument. Partial least squares (PLS) was used to develop calibration models for each ion with acceptable results (Na+, R2 = 0.86, CVSEP = 9.5 mmol/L; K+, R2 = 0.54, CVSEP = 1.4 mmol/L; Ca2+, R2 = 0.56, CVSEP = 0.18 mmol/L). Slightly improved results were obtained using a narrower wavelength region (470-925 nm) where hemoglobin, but not water, absorbed indicating that ionic interaction with hemoglobin is as effective as water in causing measurable spectral variation. Good models were also achieved for sodium in lysed blood, illustrating that cell swelling, which is correlated with sodium concentration, is not required for calibration model development.

  2. Degradation of carbohydrates during dilute sulfuric acid pretreatment can interfere with lignin measurements in solid residues.

    PubMed

    Katahira, Rui; Sluiter, Justin B; Schell, Daniel J; Davis, Mark F

    2013-04-01

    The lignin content measured after dilute sulfuric acid pretreatment of corn stover indicates more lignin than could be accounted for on the basis of the untreated corn stover lignin content. This phenomenon was investigated using a combination of (13)C cross-polarization/magic-angle spinning (CP/MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy and lignin removal using acid chlorite bleaching. Only minimal contamination with carbohydrates and proteins was observed in the pretreated corn stover. Incorporating degradation products from sugars was also investigated using (13)C-labeled sugars. The results indicate that sugar degradation products are present in the pretreatment residue and may be intimately associated with the lignin. Studies comparing whole corn stover (CS) to extractives-free corn stover [CS(Ext)] clearly demonstrated that extractives are a key contributor to the high-lignin mass balance closure (MBC). Sugars and other low molecular weight compounds present in plant extractives polymerize and form solids during pretreatment, resulting in apparent Klason lignin measurements that are biased high. PMID:23428141

  3. Validity of the tritiated thymidine method for estimating bacterial growth rates: measurement of isotope dilution during DNA synthesis

    SciTech Connect

    Pollard, P.C.; Moriarty, D.J.W.

    1984-12-01

    The rate of tritiated thymidine incorporation into DNA was used to estimate bacterial growth rates in aquatic environments. To be accurate, the calculation of growth rates has to include a factor for the dilution of isotope before incorporation. The validity of an isotope dilution analysis to determine this factor was verified in experiments reported here with cultures of a marine bacterium growing in a chemostat. Growth rates calculated from data on chemostat dilution rates and cell density agreed well with rates calculated by tritiated thymidine incorporation into DNA and isotope dilution analysis. With sufficiently high concentrations of exogenous thymidine, de novo synthesis of deoxythymidine monophosphate was inhibited, thereby preventing the endogenous dilution of isoope. The thymidine technique was also shown to be useful for measuring growth rates of mixed suspensions of bacteria growing anaerobically. Thymidine was incorporated into the DNA of a range of marine pseudomonads that were investigated. Three species did not take up thymidine. The common marine cyanobacterium Synechococcus species did not incorporate thymidine into DNA.

  4. Measurement of the phonon entropy of alloying in dilute substitutional alloys.

    NASA Astrophysics Data System (ADS)

    Delaire, Olivier; Swan-Wood, Tabitha; Kresch, Max; Fultz, Brent

    2004-03-01

    In this study, we investigate the entropic effects associated with changes in the vibrational modes of crystals sustained upon dilute substitutional alloying. Using inelastic neutron scattering, we have measured the phonon density of states (DOS) and the change in the phonon entropy of vanadium associated with the alloying of a few percent impurities of Ni, Pd, Pt or Co. The phonon entropy change upon alloying in vanadium was shown to be large and negative. In the case of 6-7% Pt and Co impurities, it is equal in magnitude to the gain in configurational entropy of alloying. We also present recent experimental results on Mo-7%Fe alloys. Using a computational model based on the classical Born-von Karman approach, we extracted interatomic force-constants from our experimental data, in order to correct the phonon DOS for the neutron-weighting due to the different neutron cross-section of the impurity. From these, we calculated phonon dispersion curves and un-weighted density of states. We also performed ab-initio calculations on supercell impurity models, which we compare to our experimental results.

  5. The geochemical behaviour of W in subduction zones: constraints from high precision isotope dilution measurements

    NASA Astrophysics Data System (ADS)

    Konig, S.; Munker, C.; Schuth, S.

    2007-12-01

    Assessing the behaviour of W during silicate Earth's differentiation is hampered by low abundances of W in terrestrial reservoirs, making sufficiently precise and accurate measurements difficult. Previous results (e.g., Newsom et al. 1996) indicate a lower W/Th of the mantle (ca. 0.19) compared to the Earth's crust, (ca. 0.26), suggesting that W appears to be more incompatible than Th. New data for MORB (Munker et al. 2007), however, demonstrate that W/Th is not significantly fractionated during dry peridotite melting, tentatively suggesting a fractionation of the two elements during crust formation by subduction related processes. We present high precision W and Nb-Ta, Zr-Hf data obtained by isotope dilution, using a mixed 183W-180Ta- 94Zr-180Hf-176Lu tracer and multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). This enables the direct determination of W and HFSE from one sample digestion. For some samples, a "nugget effect" as previously reported for PGE was observed, reflecting sample heterogeneity. Measured Ta and W abundances determined in basaltic glasses and whole rock powders from various island arc settings yield Ta/W ratios of 0.6 to 1.7, significantly lower than the values reported for MORB (4-6). In contrast, Nb/Ta for the samples overlap with MORB values, suggesting that Nb and Ta were not mobile in the magma sources. These systematic differences indicate that W does not behave as other HFSE (Nb-Ta, Zr-Hf) in subduction zones but rather displays a higher mobility in slab components. Intra-oceanic arc suites involving subducted pelagic sediment in their sources generally display higher W/Th compared to magmas without sediment-derived components in their sources, reflecting the higher initial W abundances in subducted pelagic sediments. A fractionation of W/Th during crust formation could consequently be explained by a selective W enrichment relative to Th during subduction processes.

  6. Assay dilution factors confound measures of total antioxidant capacity in polyphenol-rich juices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The extent to which sample dilution factor (DF) affects Total Antioxidant Capacity (TAC) values is poorly understood. Thus, we examined the impact of DF on the ORAC, FRAP, DPPH, and Total Phenols (TP) assays using pomegranate juice (PJ), grape juice (GJ), selected flavonoids, ascorbic acid, and ella...

  7. Measurement of asphaltene particle size distributions in crude oils diluted with n-heptane

    SciTech Connect

    Ferworn, K.A.; Svrcek, W.Y.; Mehrotra, A.K. )

    1993-05-01

    The formation and growth of asphaltene particles from heavy crude oils diluted with n-heptane at 22 C and atmospheric pressure was studied using a laser particle analyzer. The results obtained with six crude oil samples indicate that the asphaltene precipitation is an instantaneous process leading to a unimodal, log-normal distribution. At typical laboratory conditions, the particles remained essentially unaltered in size and population density. A vast majority of the particles were noted to be far from round in shape, with the mean particle size ranging from 4.5 to 291 [mu]m. It was found that the oil-to-diluent ratio is an important parameter in determining the size of the generated asphaltene particles; higher dilution ratios yielded larger particles. The mean asphaltene particle size was also found to increase with the average molar mass and the asphaltene content of crude oils.

  8. Revisiting spin-lattice relaxation time measurements for dilute spins in high-resolution solid-state NMR spectroscopy.

    PubMed

    Fu, Riqiang; Li, Jun; Cui, Jingyu; Peng, Xinhua

    2016-07-01

    Numerous nuclear magnetic resonance (NMR) measurements of spin-lattice relaxation times (T1S) for dilute spins such as (13)C have led to investigations of the motional dynamics of individual functional groups in solid materials. In this work, we revisit the Solomon equations and analyze how the heteronuclear cross relaxation between the dilute S (e.g. (13)C) and abundant I (e.g. (1)H) spins affects the measured T1S values in solid-state NMR in the absence of (1)H saturation during the recovery time. It is found theoretically that at the beginning of the S spin magnetization recovery, the existence of non-equilibrium I magnetization introduces the heteronuclear cross relaxation effect onto the recovery of the S spin magnetization and confirmed experimentally that such a heteronuclear cross relaxation effect results in the recovery overshoot phenomena for the dilute spins when T1S is on the same order of T1H, leading to inaccurate measurements of the T1S values. Even when T1S is ten times larger than T1H, the heteronuclear cross relaxation effect on the measured T1S values is still noticeable. Furthermore, this cross relaxation effect on recovery trajectory of the S spins can be manipulated and even suppressed by preparing the initial I and S magnetization, so as to obtain the accurate T1S values. A sample of natural abundance l-isoleucine powder has been used to demonstrate the T1S measurements and their corresponding measured T1C values under various experimental conditions. PMID:27187211

  9. Revisiting spin-lattice relaxation time measurements for dilute spins in high-resolution solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Fu, Riqiang; Li, Jun; Cui, Jingyu; Peng, Xinhua

    2016-07-01

    Numerous nuclear magnetic resonance (NMR) measurements of spin-lattice relaxation times (T1S) for dilute spins such as 13C have led to investigations of the motional dynamics of individual functional groups in solid materials. In this work, we revisit the Solomon equations and analyze how the heteronuclear cross relaxation between the dilute S (e.g. 13C) and abundant I (e.g. 1H) spins affects the measured T1S values in solid-state NMR in the absence of 1H saturation during the recovery time. It is found theoretically that at the beginning of the S spin magnetization recovery, the existence of non-equilibrium I magnetization introduces the heteronuclear cross relaxation effect onto the recovery of the S spin magnetization and confirmed experimentally that such a heteronuclear cross relaxation effect results in the recovery overshoot phenomena for the dilute spins when T1S is on the same order of T1H, leading to inaccurate measurements of the T1S values. Even when T1S is ten times larger than T1H, the heteronuclear cross relaxation effect on the measured T1S values is still noticeable. Furthermore, this cross relaxation effect on recovery trajectory of the S spins can be manipulated and even suppressed by preparing the initial I and S magnetization, so as to obtain the accurate T1S values. A sample of natural abundance L-isoleucine powder has been used to demonstrate the T1S measurements and their corresponding measured T1C values under various experimental conditions.

  10. Online Measurement of Exhaled NO Concentration and Its Production Sites by Fast Non-equilibrium Dilution Ion Mobility Spectrometry

    PubMed Central

    Peng, Liying; Jiang, Dandan; Wang, Zhenxin; Liu, Jiwei; Li, Haiyang

    2016-01-01

    Exhaled nitric oxide (NO) is one of the most promising breath markers for respiratory diseases. Its profile for exhalation and the respiratory NO production sites can provide useful information for medical disease diagnosis and therapeutic procedures. However, the high-level moisture in exhaled gas always leads to the poor selectivity and sensitivity for ion spectrometric techniques. Herein, a method based on fast non-equilibrium dilution ion mobility spectrometry (NED-IMS) was firstly proposed to directly monitor the exhaled NO profile on line. The moisture interference was eliminated by turbulently diluting the original moisture to 21% of the original with the drift gas and dilution gas. Weak enhancement was observed for humid NO response and its limit of detection at 100% relative humidity was down to 0.58 ppb. The NO concentrations at multiple exhalation flow rates were measured, while its respiratory production sites were determined by using two-compartment model (2CM) and Högman and Meriläinen algorithm (HMA). Last but not the least, the NO production sites were analyzed hourly to tentatively investigate the daily physiological process of NO. The results demonstrated the capacity of NED-IMS in the real-time analysis of exhaled NO and its production sites for clinical diagnosis and assessment. PMID:26975333

  11. Online Measurement of Exhaled NO Concentration and Its Production Sites by Fast Non-equilibrium Dilution Ion Mobility Spectrometry.

    PubMed

    Peng, Liying; Jiang, Dandan; Wang, Zhenxin; Liu, Jiwei; Li, Haiyang

    2016-01-01

    Exhaled nitric oxide (NO) is one of the most promising breath markers for respiratory diseases. Its profile for exhalation and the respiratory NO production sites can provide useful information for medical disease diagnosis and therapeutic procedures. However, the high-level moisture in exhaled gas always leads to the poor selectivity and sensitivity for ion spectrometric techniques. Herein, a method based on fast non-equilibrium dilution ion mobility spectrometry (NED-IMS) was firstly proposed to directly monitor the exhaled NO profile on line. The moisture interference was eliminated by turbulently diluting the original moisture to 21% of the original with the drift gas and dilution gas. Weak enhancement was observed for humid NO response and its limit of detection at 100% relative humidity was down to 0.58 ppb. The NO concentrations at multiple exhalation flow rates were measured, while its respiratory production sites were determined by using two-compartment model (2CM) and Högman and Meriläinen algorithm (HMA). Last but not the least, the NO production sites were analyzed hourly to tentatively investigate the daily physiological process of NO. The results demonstrated the capacity of NED-IMS in the real-time analysis of exhaled NO and its production sites for clinical diagnosis and assessment. PMID:26975333

  12. Assay Dilution Factors Confound Measures of Total Antioxidant Capacity in Polyphenol-Rich Juices

    PubMed Central

    Bolling, Bradley W.; Chen, Ya-Yen; Kamil, Alison G.; Chen, C-Y. Oliver

    2016-01-01

    The extent to which sample dilution factor (DF) affects total antioxidant capacity (TAC) values is poorly understood. Thus, we examined the impact of DF on the ORAC, FRAP, DPPH, and total phenols (TP) assays using pomegranate juice (PJ), grape juice (GJ), selected flavonoids, ascorbic acid, and ellagic acid. For ORAC, GJ was comparable to PJ at DF 750, but at DF 2000, the ORAC value of GJ was 40% more than PJ. Increasing DF increased GJ and PJ, DPPH, TP, and FRAP values 11% and 14%, respectively. Increased test concentrations of quercetin and catechin resulted in 51% and 126% greater ORAC values, but decreased naringenin by 68%. Flavonoids, but not ellagic acid or ascorbic acid, may contribute to the dilution effect on the variation of final TAC values. Thus, reporting TAC or TP using a single DF may introduce uncertainty about the confidence of TAC assay values, especially when comparing different juices. These results underscore the importance of using compatible test standards for reporting TAC values. PMID:22251245

  13. Unification and Infinite Series

    ERIC Educational Resources Information Center

    Leyendekkers, J. V.; Shannon, A. G.

    2008-01-01

    Some infinite series are analysed on the basis of the hypergeometric function and integer structure and modular rings. The resulting generalized functions are compared with differentiation of the "mother" series. (Contains 1 table.)

  14. Body water measurement in growth disorders: a comparison of bioelectrical impedance and skinfold thickness techniques with isotope dilution.

    PubMed Central

    Gregory, J W; Greene, S A; Scrimgeour, C M; Rennie, M J

    1991-01-01

    Total body water was estimated as part of the assessment of body composition in children with growth disorders, using the newly commercially available method of bioelectrical impedance. This was undertaken to compare the precision and accuracy of the results with those derived from skinfold thickness against measurement of stable isotopically labelled water (H2(18)O) dilution as a standard. The comparisons were carried out to see to what extent the impedance method could be applied with confidence to assessment of children with growth disorders. Total body water was derived from impedance (I) using an association with height (Ht2/I). Impedance and skinfold thickness estimates of total body water were equally precise when compared with values obtained from H2(18)O dilution (limits of agreement -1.9 to +1.3 and -1.7 to +2.0 kg respectively). The mean intraobserver coefficient of variation for repeat measurements of impedance was 0.9% compared with 4.6% for skinfold thickness with an interobserver coefficient of variation for impedance of 2.8%. Bioelectrical impedance estimation of body composition is likely to be of value in the growth clinic when expertise in measurement of skinfold thickness is limited or repeated measurements are to be undertaken by different observers. PMID:2001107

  15. Near-infrared spectroscopy extended with indocyanine green dye dilution for cerebral blood flow measurement: Median values in healthy volunteers

    NASA Astrophysics Data System (ADS)

    Mudra, R.; Muroi, C.; Niederer, P.; Keller, E.

    2008-09-01

    The cerebral blood flow (CBF) is an important vital parameter in neurointensive care. Currently, there is no non-invasive method for its measurement that can easily be applied at the bedside. A new tool to determine CBF is based on near-infrared spectroscopy (NIRS) applied together with indocyanine green (ICG) dye dilution. From a bilateral measurement on selected regions on the head of infrared (IR) absorption at various wavelengths during the dilution maneuver, the vascular perfusion characteristics of the two brain hemispheres can be determined in terms of mean transit time (mtt) of ICG, cerebral blood volume (CBV) and CBF. So far, on nine healthy volunteers, NIRS ICG dye dilution bihemispheric measurements were performed, which yielded to mtt given as median (range) of 9.3 s (5.1-16.3 s), CBV of 3.5 ml/100 g (1.7-4.1 ml/100 g), and CBF of 18.2 ml/(100 g×min) [11.1-48.6 ml/(100 g×min)]. Additionally, the blood flow index (BFI) was calculated with BFI= 13.8 mg/(100 g×s) [6.6-15.2 mg/(100 g×s)]. The Spearman rank correlation coefficient between CBF and BFI was RS = 0.76. However, as the Bland & Altman plot between CBFNIRS and the CBFBFI documents, the limits of agreement are rather wide (21.9±6.7). Under physiological conditions in healthy volunteers, no differences could be detected between the hemispheres.

  16. Learning to See the Infinite: Measuring Visual Literacy Skills in a 1st-Year Seminar Course

    ERIC Educational Resources Information Center

    Palmer, Michael S.; Matthews, Tatiana

    2015-01-01

    Visual literacy was a stated learning objective for the fall 2009 iteration of a first-year seminar course. To help students develop visual literacy skills, they received formal instruction throughout the semester and completed a series of carefully designed learning activities. The effects of these interventions were measured using a one-group…

  17. Development of traceable precision dynamic dilution method to generate dimethyl sulphide gas mixtures at sub-nanomole per mole levels for ambient measurement.

    PubMed

    Kim, Mi Eon; Kim, Yong Doo; Kang, Ji Hwan; Heo, Gwi Suk; Lee, Dong Soo; Lee, Sangil

    2016-04-01

    Dimethyl sulphide (DMS) is an important compound in global atmospheric chemistry and climate change. Traceable international standards are essential for measuring accurately the long-term global trend in ambient DMS. However, developing accurate gas standards for sub-nanomole per mole (nmol/mol) mole fractions of DMS in a cylinder is challenging, because DMS is reactive and unstable. In this study, a dynamic dilution method that is traceable and precise was developed to generate sub-nmol/mol DMS gas mixtures with a dynamic dilution system based on sonic nozzles and a long-term (>5 years) stable 10 μmol/mol parent DMS primary standard gas mixtures (PSMs). The dynamic dilution system was calibrated with traceable methane PSMs, and its estimated dilution factors were used to calculate the mole fractions of the dynamically generated DMS gas mixtures. A dynamically generated DMS gas mixture and a 6 nmol/mol DMS PSM were analysed against each other by gas chromatography with flame-ionisation detection (GC/FID) to evaluate the dilution system. The mole fractions of the dynamically generated DMS gas mixture determined against a DMS PSM and calculated with the dilution factor agreed within 1% at 6 nmol/mol. In addition, the dynamically generated DMS gas mixtures at various mole fractions between 0.4 and 11.7 nmol/mol were analysed by GC/FID and evaluated for their linearity. The analytically determined mole fractions showed good linearity with the mole fractions calculated with the dilution factors. Results showed that the dynamic dilution method generates DMS gas mixtures ranging between 0.4 nmol/mol and 12 nmol/mol with relative expanded uncertainties of less than 2%. Therefore, the newly developed dynamic dilution method is a promising reference method for generating sub-nmol/mol DMS gas standards for accurate ambient measurements. PMID:26838438

  18. Lyapunov exponents for infinite dimensional dynamical systems

    NASA Technical Reports Server (NTRS)

    Mhuiris, Nessan Mac Giolla

    1987-01-01

    Classically it was held that solutions to deterministic partial differential equations (i.e., ones with smooth coefficients and boundary data) could become random only through one mechanism, namely by the activation of more and more of the infinite number of degrees of freedom that are available to such a system. It is only recently that researchers have come to suspect that many infinite dimensional nonlinear systems may in fact possess finite dimensional chaotic attractors. Lyapunov exponents provide a tool for probing the nature of these attractors. This paper examines how these exponents might be measured for infinite dimensional systems.

  19. Simultaneous temperature and multi-species measurements in opposed jet flames of nitrogen-diluted hydrogen and air

    NASA Technical Reports Server (NTRS)

    Wehrmeyer, J. A.; Cheng, T. S.; Pitz, R. W.; Nandula, S.; Wilson, L. G.; Pellett, G. L.

    1991-01-01

    A narrowband UV Raman scattering system is used to obtain measurement profiles of major and minor species concentrations, temperature, and mixture fraction in opposed jet diffusion flames. The measurement profiles can be compared to previously obtained temperature and concentration profiles (Pellett et al., 1989), obtained using CARS, and they can also be qualitatively compared to the predicted concentration and temperature profiles in pure hydrogen/air flames (Gutheil and Williams, 1990) and in diluted hydrogen/air flames (Dixon-Lewis and Missaghi, 1988; Ho and Isaac, 1991). The applied stress-rates for the two flame conditions studied are 240/s and 340/s, with respective hydrogen concentrations in the fuel jet of 0.67 and 0.83, on a mole fraction basis (0.13 and 0.26 hydrogen mass fractions, respectively).

  20. The Infinite Hotel

    ERIC Educational Resources Information Center

    Wanko, Jeffrey J.

    2009-01-01

    This article provides a historical context for the debate between Georg Cantor and Leopold Kronecker regarding the cardinality of different infinities and incorporates the short story "Welcome to the Hotel Infinity," which uses the analogy of a hotel with an infinite number of rooms to help explain this concept. Wanko makes use of this history and…

  1. Contribution of the finite volume point dilution method for measurement of groundwater fluxes in a fractured aquifer.

    PubMed

    Jamin, P; Goderniaux, P; Bour, O; Le Borgne, T; Englert, A; Longuevergne, L; Brouyère, S

    2015-11-01

    Measurement of groundwater fluxes is the basis of all hydrogeological study, from hydraulic characterization to the most advanced reactive transport modeling. Usual groundwater flux estimation with Darcy's law may lead to cumulated errors on spatial variability, especially in fractured aquifers where local direct measurement of groundwater fluxes becomes necessary. In the present study, both classical point dilution method (PDM) and finite volume point dilution method (FVPDM) are compared on the fractured crystalline aquifer of Ploemeur, France. The manipulation includes the first use of the FVPDM in a fractured aquifer using a double packer. This configuration limits the vertical extent of the tested zone to target a precise fracture zone of the aquifer. The result of this experiment is a continuous monitoring of groundwater fluxes that lasted for more than 4 days. Measurements of groundwater flow rate in the fracture (Q(t)) by PDM provide good estimates only if the mixing volume (V(w)) (volume of water in which the tracer is mixed) is precisely known. Conversely, the FVPDM allows for an independent estimation of V(w) and Q(t), leading to better precision in case of complex experimental setup such as the one used. The precision of a PDM does not rely on the duration of the experiment while a FVPDM may require long experimental duration to guarantees a good precision. Classical PDM should then be used for rapid estimation of groundwater flux using simple experimental setup. On the other hand, the FVPDM is a more precise method that has a great potential for development but may require longer duration experiment to achieve a good precision if the groundwater fluxes investigated are low and/or the mixing volume is large. PMID:26519822

  2. Contribution of the finite volume point dilution method for measurement of groundwater fluxes in a fractured aquifer

    NASA Astrophysics Data System (ADS)

    Jamin, P.; Goderniaux, P.; Bour, O.; Le Borgne, T.; Englert, A.; Longuevergne, L.; Brouyère, S.

    2015-11-01

    Measurement of groundwater fluxes is the basis of all hydrogeological study, from hydraulic characterization to the most advanced reactive transport modeling. Usual groundwater flux estimation with Darcy's law may lead to cumulated errors on spatial variability, especially in fractured aquifers where local direct measurement of groundwater fluxes becomes necessary. In the present study, both classical point dilution method (PDM) and finite volume point dilution method (FVPDM) are compared on the fractured crystalline aquifer of Ploemeur, France. The manipulation includes the first use of the FVPDM in a fractured aquifer using a double packer. This configuration limits the vertical extent of the tested zone to target a precise fracture zone of the aquifer. The result of this experiment is a continuous monitoring of groundwater fluxes that lasted for more than 4 days. Measurements of groundwater flow rate in the fracture (Qt) by PDM provide good estimates only if the mixing volume (Vw) (volume of water in which the tracer is mixed) is precisely known. Conversely, the FVPDM allows for an independent estimation of Vw and Qt, leading to better precision in case of complex experimental setup such as the one used. The precision of a PDM does not rely on the duration of the experiment while a FVPDM may require long experimental duration to guarantees a good precision. Classical PDM should then be used for rapid estimation of groundwater flux using simple experimental setup. On the other hand, the FVPDM is a more precise method that has a great potential for development but may require longer duration experiment to achieve a good precision if the groundwater fluxes investigated are low and/or the mixing volume is large.

  3. Dilution and aerosol dynamics within a diesel car exhaust plume—CFD simulations of on-road measurement conditions

    NASA Astrophysics Data System (ADS)

    Uhrner, U.; von Löwis, S.; Vehkamäki, H.; Wehner, B.; Bräsel, S.; Hermann, M.; Stratmann, F.; Kulmala, M.; Wiedensohler, A.

    Vehicle particle emissions are studied extensively because of their health effects, contribution to ambient PM levels and possible impact on climate. The aim of this work was to obtain a better understanding of secondary particle formation and growth in a diluting vehicle exhaust plume using 3-d information of simulations together with measurements. Detailed coupled computational fluid dynamics (CFD) and aerosol dynamics simulations have been conducted for H 2SO 4-H 2O and soot particles based on measurements within a vehicle exhaust plume under real conditions on public roads. Turbulent diffusion of soot and nucleation particles is responsible for the measured decrease of number concentrations within the diesel car exhaust plume and decreases coagulation rates. Particle size distribution measurements at 0.45 and 0.9 m distance to the tailpipe indicate a consistent soot mode (particle diameter Dp˜50 nm) at variable operating conditions. Soot mode number concentrations reached up to 10 13 m -3 depending on operating conditions and mixing. For nucleation particles the simulations showed a strong sensitivity to the spatial dilution pattern, related cooling and exhaust H 2SO 4(g). The highest simulated nucleation rates were about 0.05-0.1 m from the axis of the plume. The simulated particle number concentration pattern is in approximate accordance with measured concentrations, along the jet centreline and 0.45 and 0.9 m from the tailpipe. Although the test car was run with ultralow sulphur fuel, high nucleation particle ( Dp⩽15 nm) concentrations (>10 13 m -3) were measured under driving conditions of strong acceleration or the combination of high vehicle speed (>140 km h -1) and high engine rotational speed (>3800 revolutions per minute (rpm)). Strong mixing and cooling caused rapid nucleation immediately behind the tailpipe, so that the highest particle number concentrations were recorded at a distance, x=0.45 m behind the tailpipe. The simulated growth of H 2SO 4

  4. Characterization of dilute optical lattices using pump-probe spectroscopy and photon correlation measurements

    NASA Astrophysics Data System (ADS)

    Clements, Ethan; Ross, Preston; Rapp, Anthony; Cai, Hong; Reigle, Alex; Schlonsky, Eli; Lee, Hoseong; Clemens, James; Bali, Samir

    2016-05-01

    We experimentally investigate optical lattices using three different methods: pump-probe spectroscopy of vibrational energy levels, photon correlation of light scattered by cold atoms, and fluorescence imaging. Photon correlations of the scattered light can be used to measure lattice dwell times and crossover times between lattice sites. From this information we can derive the diffusion constant which can then be compared to direct measurement via fluorescence imaging. Furthermore, by Fourier transforming the time delayed photon correlations we can obtain the intensity spectrum which can be compared directly to pump-probe spectroscopy of the vibrational energy levels. We plan to carefully study situations in which the atomic transport properties deviate from Boltzman Gibbs statistics.

  5. Short communication: milk output in llamas (Lama glama) in relation to energy intake and water turnover measured by an isotope dilution technique.

    PubMed

    Riek, A; Klinkert, A; Gerken, M; Hummel, J; Moors, E; Südekum, K-H

    2013-03-01

    Despite the fact that llamas have become increasingly popular as companion and farm animals in both Europe and North America, scientific knowledge on their nutrient requirements is scarce. Compared with other livestock species, relatively little is known especially about the nutrient and energy requirements for lactating llamas. Therefore, we aimed to measure milk output in llama dams using an isotope dilution technique and relate it to energy intakes at different stages of lactation. We also validated the dilution technique by measuring total water turnover (TWT) directly and comparing it with values estimated by the isotope dilution technique. Our study involved 5 lactating llama dams and their suckling young. Milk output and TWT were measured at 4 stages of lactation (wk 3, 10, 18, and 26 postpartum). The method involved the application of the stable hydrogen isotope deuterium ((2)H) to the lactating dam. Drinking water intake and TWT decreased significantly with lactation stage, whether estimated by the isotope dilution technique or calculated from drinking water and water ingested from feeds. In contrast, lactation stage had no effect on dry matter intake, metabolizable energy (ME) intake, or the milk water fraction (i.e., the ratio between milk water excreted and TWT). The ratios between TWT measured and TWT estimated (by isotope dilution) did not differ with lactation stage and were close to 100% in all measurement weeks, indicating that the D(2)O dilution technique estimated TWT with high accuracy and only small variations. Calculating the required ME intakes for lactation from milk output data and gross energy content of milk revealed that, with increasing lactation stage, ME requirements per day for lactation decreased but remained constant per kilogram of milk output. Total measured ME intakes at different stages of lactation were similar to calculated ME intakes from published recommendation models for llamas. PMID:23332845

  6. Squashed entanglement in infinite dimensions

    NASA Astrophysics Data System (ADS)

    Shirokov, M. E.

    2016-03-01

    We analyse two possible definitions of the squashed entanglement in an infinite-dimensional bipartite system: direct translation of the finite-dimensional definition and its universal extension. It is shown that the both definitions produce the same lower semicontinuous entanglement measure possessing all basis properties of the squashed entanglement on the set of states having at least one finite marginal entropy. It is also shown that the second definition gives an adequate lower semicontinuous extension of this measure to all states of the infinite-dimensional bipartite system. A general condition relating continuity of the squashed entanglement to continuity of the quantum mutual information is proved and its corollaries are considered. Continuity bound for the squashed entanglement under the energy constraint on one subsystem is obtained by using the tight continuity bound for quantum conditional mutual information (proved in the Appendix by using Winter's technique). It is shown that the same continuity bound is valid for the entanglement of formation. As a result the asymptotic continuity of the both entanglement measures under the energy constraint on one subsystem is proved.

  7. Dilution Confusion: Conventions for Defining a Dilution

    ERIC Educational Resources Information Center

    Fishel, Laurence A.

    2010-01-01

    Two conventions for preparing dilutions are used in clinical laboratories. The first convention defines an "a:b" dilution as "a" volumes of solution A plus "b" volumes of solution B. The second convention defines an "a:b" dilution as "a" volumes of solution A diluted into a final volume of "b". Use of the incorrect dilution convention could affect…

  8. Laboratory measurements of radiance and reflectance spectra of dilute secondary-treated sewage sludge

    NASA Technical Reports Server (NTRS)

    Witte, W. G.; Usry, J. W.; Whitlock, C. H.; Gurganus, E. A.

    1977-01-01

    The National Aeronautics and Space Administration (NASA), in cooperation with the Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA), conducted a research program to evaluate the feasibility of remotely monitoring ocean dumping of waste products such as acid and sewage sludge. One aspect of the research program involved the measurements of upwelled spectral signatures for sewage-sludge mixtures of different concentrations in an 11600-liter tank. This paper describes the laboratory arrangement and presents radiance and reflectance spectra in the visible and near-infrared ranges for concentrations ranging from 9.7 to 180 ppm of secondary-treated sewage sludge mixed with two types of base water. Results indicate that upwelled radiance varies in a near-linear manner with concentration and that the sludge has a practically flat signal response between 420 and 970 nm. Reflectance spectra were obtained for the sewage-sludge mixtures at all wavelengths and concentrations.

  9. Measured current drainage through holes in various dielectrics up to 2 kilovolts in a dilute plasma

    NASA Technical Reports Server (NTRS)

    Grier, N. T.; Mckinzie, D. J., Jr.

    1972-01-01

    The electron current drained from a plasma through approximately 0.05 cm diameter holes in eight possible space applicable dielectrics placed on a probe biased at voltages up to 2000 V dc have been determined both theoretically and experimentally. The dielectrics tested were Parylene C and N, Teflon FEP type C, Teflon TFE, Nomex, quartz 7940 Corning Glass, Mylar A, and Kapton H polymide film. A Laplace field was used to predict an upper limit for the drainage current. The measured current was less than the computed current for quartz, Teflon FEP, and the 0.0123 cm thick sample of Parylene N for all voltages tested. The drainage current through the other dielectrics became equal to or greater than the computed current at a voltage below 2000 V. The magnitudes of the currents were between 0.1 and 10 microamperes for most of the dielectrics.

  10. Dermal uptake of 18 dilute aqueous chemicals: in vivo disappearance-method measures greatly exceed in vitro-based predictions.

    PubMed

    Bogen, Kenneth T

    2013-07-01

    Average rates of total dermal uptake (Kup ) from short-term (e.g., bathing) contact with dilute aqueous organic chemicals (DAOCs) are typically estimated from steady-state in vitro diffusion-cell measures of chemical permeability (Kp ) through skin into receptor solution. Widely used ("PCR-vitro") methods estimate Kup by applying diffusion theory to increase Kp predictions made by a physico-chemical regression (PCR) model that was fit to a large set of Kp measures. Here, Kup predictions for 18 DAOCs made by three PCR-vitro models (EPA, NIOSH, and MH) were compared to previous in vivo measures obtained by methods unlikely to underestimate Kup . A new PCR model fit to all 18 measures is accurate to within approximately threefold (r = 0.91, p < 10(-5) ), but the PCR-vitro predictions (r > 0.63) all tend to underestimate the Kup measures by mean factors (UF, and p value for testing UF = 1) of 10 (EPA, p < 10(-6) ), 11 (NIOSH, p < 10(-8) ), and 6.2 (MH, p = 0.018). For all three PCR-vitro models, log(UF) correlates negatively with molecular weight (r(2) = 0.31 to 0.84, p = 0.017 to < 10(-6) ) but not with log(vapor pressure) as an additional predictor (p > 0.05), so vapor pressure appears not to explain the significant in vivo/PCR-vitro discrepancy. Until this discrepancy is explained, careful in vivo measures of Kup should be obtained for more chemicals, the expanded in vivo database should be compared to in vitro-based predictions, and in vivo data should be considered in assessing aqueous dermal exposure and its uncertainty. PMID:23051616

  11. Laboratory measurements of radiance and reflectance spectra of a dilute biosolid industrial waste product

    NASA Technical Reports Server (NTRS)

    Usry, J. W.; Witte, W. G.; Whitlock, C. H.; Gurganus, E. A.

    1979-01-01

    Experimental measurements were made of upwelled spectral signatures of various concentrations of industrial waste products mixed with water in a large water tank. Radiance and reflectance spectra for a biosolid waste product (sludge) mixed with conditioned tap water and natural river water are reported. Results of these experiments indicate that reflectance increases with increasing concentration of the sludge at practically all wavelengths for concentration of total suspended solids up to 117 ppm in conditioned tap water and 171 ppm in natural river water. Significant variations in the spectra were observed and may be useful in defining spectral characteristics for this waste product. No significant spectral differences were apparent in the reflectance spectra of the two experiments, especially for wavelengths greater than 540 nm. Reflectance values, however, were generally greater in natural river water for wavelengths greater than 540 nm. Reflectance may be considered to increase linearly with concentration of total suspended solids from 5 to 171 ppm at all wavelengths without introducing errors larger than 10 percent.

  12. Measurement of interfacial undercooling in a dilute Pb Sn alloy near the regime of morphological instability

    NASA Astrophysics Data System (ADS)

    Sen, S.; Dhindaw, B. K.; Curreri, P. A.; Peters, P.; Kaukler, W. F.

    1998-10-01

    The solid/liquid (s/l) interfacial Seebeck technique was used to measure interfacial undercooling in a Pb-1 wt% Sn alloy. For plane front solidification an undercooling in the range of 0.54-0.57°C was recorded. However, for growth velocities between 6 and 15 μm/s the undercooling increased with increase in velocity. This is in contradiction to the theoretical predictions based on growth at the extremum condition. A modified analytical expression was developed based on the marginal stability criterion to predict undercooling for growth velocities immediately over the limit of morphological stability. Between 6 and 15 μm/s the trend predicted by this modified expression is in qualitative agreement with the experimental results. This model is more consistent with the analysis of Venugopal and Kirkaldy which states that the extremum condition criterion is not applicable in the marginal stability regime. At higher growth velocities between 20 and 50 μm/s where stable cellular growth is expected the undercooling decreased with increase in velocity. The predictions of Burden and Hunt based on extremum criterion agree reasonably well with the experimental results in this velocity range. Finally, the importance of nonequilibrium phase diagram parameters such as partition coefficient and liquidus slope were also evaluated using the experimental undercooling results obtained in this investigation.

  13. Production of highly-enriched 134Ba for a reference material for isotope dilution mass spectrometry measurements

    SciTech Connect

    J.J. Horkley; K.P E.M. Gantz; J.E. Davis; R.R. Lewis; J.P. Crow; C.A. Poole; T.S. Grimes; J.J. Giglio

    2015-03-01

    t Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure ‘‘spike’’ solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for ‘‘age’’ determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determine 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution,

  14. Production of highly-enriched 134Ba for a reference material for isotope dilution mass spectrometry measurements

    DOE PAGESBeta

    Horkley, J. J.; Carney, K. P.; Gantz, E. M.; Davies, J. E.; Lewis, R. R.; Crow, J. P.; Poole, C. A.; Grimes, T. S.; Giglio, J. J.

    2015-03-17

    Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure “spike” solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for “age” determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determinemore » 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution, and the encapsulation of the materials will be described.« less

  15. Production of highly-enriched 134Ba for a reference material for isotope dilution mass spectrometry measurements

    SciTech Connect

    Horkley, J. J.; Carney, K. P.; Gantz, E. M.; Davies, J. E.; Lewis, R. R.; Crow, J. P.; Poole, C. A.; Grimes, T. S.; Giglio, J. J.

    2015-03-17

    Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure “spike” solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for “age” determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determine 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution, and the encapsulation of the materials will be described.

  16. Measurements of Turbulence Attenuation by a Dilute Dispersion of Solid Particles in Homogeneous Isotropic Turbulence

    NASA Technical Reports Server (NTRS)

    Eaton, John; Hwang, Wontae; Cabral, Patrick

    2002-01-01

    the addition of gravity as a variable parameter may help us to better understand the physics of turbulence attenuation. The experiments are conducted in a turbulence chamber capable of producing stationary or decaying isotropic turbulence with nearly zero mean flow and Taylor microscale Reynolds numbers up to nearly 500. The chamber is a 410 mm cubic box with the corners cut off to make it approximately spherical. Synthetic jet turbulence generators are mounted in each of the eight corners of the box. Each generator consists of a loudspeaker forcing a plenum and producing a pulsed jet through a 20 mm diameter orifice. These synthetic jets are directed into ejector tubes pointing towards the chamber center. The ejector tubes increase the jet mass flow and decrease the velocity. The jets then pass through a turbulence grid. Each of the eight loudspeakers is forced with a random phase and frequency. The resulting turbulence is highly Isotropic and matches typical behavior of grid turbulence. Measurements of both phases are acquired using particle image velocimetry (PIV). The gas is seeded with approximately 1 micron diameter seeding particles while the solid phase is typically 150 micron diameter spherical glass particles. A double-pulsed YAG laser and a Kodak ES-1.0 10-bit PIV camera provide the PIV images. Custom software is used to separate the images into individual images containing either gas-phase tracers or large particles. Modern high-resolution PIV algorithms are then used to calculate the velocity field. A large set of image pairs are acquired for each case, then the results are averaged both spatially and over the ensemble of acquired images. The entire apparatus is mounted in two racks which are carried aboard NASA's KC-135 Flying Microgravity Laboratory. The rack containing the turbulence chamber, the laser head, and the camera floats freely in the airplane cabin (constrained by competent NASA personnel) to minimize g-jitter.

  17. An Isotope Dilution Method for High-frequency Measurements of Dissolved Inorganic Carbon concentration in the Surface Ocean

    NASA Astrophysics Data System (ADS)

    Huang, K.; Bender, M. L.; Wanninkhof, R. H.; Cassar, N.

    2013-12-01

    Dissolved inorganic carbon (DIC) is one of the most important species in the ocean carbon system. An autonomous system using isotope dilution as its core method has been developed to obtain high-frequency measurements of dissolved inorganic carbon (DIC) concentrations in the surface ocean. This system accurately mixes a seawater sample and a 13C-labeled sodium bicarbonate solution (spike). The mixed solution is then acidified and sent through a gas permeable membrane contactor. CO2 derived from DIC in the mixture is extracted by a CO2-free gas stream, and is sent to a cavity ring-down spectrometer to analyze its 13C/12C ratio. [DIC] of the seawater can then be derived from the measured 13C/12C, the known mixing ratio and the [DI13C] of the spike. The method has been tested under a wide [DIC] range (1800-2800 μmol/kg) in the laboratory. It has also been deployed on a cruise that surveyed ocean waters to the south of Florida. At a sampling resolution of 4 minutes (15 samples per hour), the relative standard deviation of DIC determined from the laboratory tests and the field deployment is ×0.07% and ×0.09%, respectively. The accuracy of the method is better than 0.1% except where [DIC] varies faster than 5 μmol/kg per minute. Based on the laboratory and field evaluations, we conclude that this method can provide accurate underway [DIC] measurements at high resolution in most oceanic regions. Schematic illustration of the work flow.

  18. Laboratory Measurements Of Pure And Diluted Methanol In Water Ice In The Nir And Mir Wavelength Ranges.

    NASA Astrophysics Data System (ADS)

    Merlin, Frederic; Quirico, E.; Barucci, M. A.; Gourgeot, F.

    2012-10-01

    Observations performed in the mid infrared (MIR) show evidence of large amount of ices in the Galaxy. Water ice is the most abundant but other chemical compounds, such as carbon monoxide and methanol, can be present and be enriched in molecular clouds or protostellar disks (Garrod & Pauly 2011). Methanol forms mainly on ice-covered dust grain surfaces primarily through hydrogenation of CO or from an electron-irradiated H2O-CH4 icy mixture (see Moore & Hudson 1998 or Dartois et al. 1999). These compounds appear to be pristine in the minor bodies of the solar system (Merlin et al. 2012) and were found in comets (Bockelée-Morvan et al. 2004) and on the surface of Trans-Neptunian Objects and Centaurs (Barucci et al. 2012 for instance for methanol). Laboratory measurements are needed to constrain information on the physical and chemical properties of these objects and give constraint on the formation and evolution of the solar system. In the aim to give constraints on the physical properties of H2O and CH3OH from their spectral behavior, we performed laboratory measurements in the observable wavelength ranges accessible from the space and ground based observatories (in the MIR and in the near IR, respectively). We present new laboratory measurements depending on the ratio of each component and the ambient temperature (from 18 to 145K) for the amorphous and the crystalline phases. We focus our analyses on the effects of the dilution level of CH3OH in H2O and the phase changes, especially on the absorption bands located at 2,3 and 3,45 microns (associated to CH asymmetric stretch) and the possible formation of the mono hydrate CH3OH:H2O based on the 3,12 micron band (associated to the OH stretch).

  19. Measurement of mercury species in human blood using triple spike isotope dilution with SPME-GC-ICP-DRC-MS.

    PubMed

    Sommer, Yuliya L; Verdon, Carl P; Fresquez, Mark R; Ward, Cynthia D; Wood, Elliott B; Pan, Yi; Caldwell, Kathleen L; Jones, Robert L

    2014-08-01

    The measurement of different mercury compounds in human blood can provide valuable information about the type of mercury exposure. To this end, our laboratory developed a biomonitoring method for the quantification of inorganic (iHg), methyl (MeHg), and ethyl (EtHg) mercury in whole blood using a triple-spike isotope dilution (TSID) quantification method employing capillary gas chromatography (GC) and inductively coupled dynamic reaction cell mass spectrometry (ICP-DRC-MS). We used a robotic CombiPAL(®) sample handling station featuring twin fiber-based solid-phase microextraction (SPME) injector heads. The use of two SPME fibers significantly reduces sample analysis cycle times making this method very suitable for high sample throughput, which is a requirement for large public health biomonitoring studies. Our sample preparation procedure involved solubilization of blood samples with tetramethylammonium hydroxide (TMAH) followed by the derivatization with sodium tetra(n-propyl)borate (NaBPr(4)) to promote volatility of mercury species. We thoroughly investigated mercury species stability in the blood matrix during the course of sample treatment and analysis. The method accuracy for quantifying iHg, MeHg, and EtHg was validated using NIST standard reference materials (SRM 955c level 3) and the Centre de Toxicologie du Québec (CTQ) proficiency testing (PT) samples. The limit of detection (LOD) for iHg, MeHg, and EtHg in human blood was determined to be 0.27, 0.12, and 0.16 μg/L, respectively. PMID:24948088

  20. Measurement of Mercury Species in Human Blood using Triple Spike Isotope Dilution with SPME-GC-ICP-DRC-MS

    PubMed Central

    Sommer, Yuliya L.; Verdon, Carl P.; Fresquez, Mark R.; Ward, Cynthia D.; Wood, Elliott B.; Pan, Yi; Caldwell, Kathleen L.; Jones, Robert L.

    2015-01-01

    The measurement of different mercury compounds in human blood can provide valuable information about the type of mercury exposure. To this end, our laboratory developed a biomonitoring method for the quantification of inorganic (iHg), methyl (MeHg) and ethyl (EtHg) mercury in whole blood using a triple spike isotope dilution (TSID) quantification method employing capillary gas chromatography (GC) and inductively coupled dynamic reaction cell mass spectrometry (ICP-DRC-MS). We used a robotic CombiPAL® sample handling station featuring twin fiber-based solid phase microextraction (SPME) injector heads. The use of two SPME fibers significantly reduces sample analysis cycle times making this method very suitable for high sample throughput, which is a requirement for large public health biomonitoring studies. Our sample preparation procedure involved solubilization of blood samples with tetramethylammonium hydroxide (TMAH) followed by the derivatization with sodium tetra(n-propyl)borate (NaBPr4) to promote volatility of mercury species. We thoroughly investigated mercury species stability in the blood matrix during the course of sample treatment and analysis. The method accuracy for quantifying iHg, MeHg and EtHg was validated using NIST standard reference materials (SRM 955c Level 3) and the Centre de Toxicologie du Québec (CTQ) proficiency testing (PT) samples. The limit of detection (LOD) for iHg, MeHg and EtHg in human blood was determined to be 0.27, 0.12, and 0.16 μg/L, respectively. PMID:24948088

  1. Can the single-breath helium dilution method predict lung volumes as measured by whole-body plethysmography?*

    PubMed Central

    Coertjens, Patrícia Chaves; Knorst, Marli Maria; Dumke, Anelise; Pasqualoto, Adriane Schmidt; Riboldi, João; Barreto, Sérgio Saldanha Menna

    2013-01-01

    OBJECTIVE: To compare TLC and RV values obtained by the single-breath helium dilution (SBHD) method with those obtained by whole-body plethysmography (WBP) in patients with normal lung function, patients with obstructive lung disease (OLD), and patients with restrictive lung disease (RLD), varying in severity, and to devise equations to estimate the SBHD results. METHODS: This was a retrospective cross-sectional study involving 169 individuals, of whom 93 and 49 presented with OLD and RLD, respectively, the remaining 27 having normal lung function. All patients underwent spirometry and lung volume measurement by both methods. RESULTS: TLC and RV were higher by WBP than by SBHD. The discrepancy between the methods was more pronounced in the OLD group, correlating with the severity of airflow obstruction. In the OLD group, the correlation coefficient of the comparison between the two methods was 0.57 and 0.56 for TLC and RV, respectively (p < 0.001 for both). We used regression equations, adjusted for the groups studied, in order to predict the WBP values of TLC and RV, using the corresponding SBHD values. It was possible to create regression equations to predict differences in TLC and RV between the two methods only for the OLD group. The TLC and RV equations were, respectively, ∆TLCWBP-SBHD in L = 5.264 − 0.060 × FEV1/FVC (r2 = 0.33; adjusted r2 = 0.32) and ∆RVWBP-SBHD in L = 4.862 − 0.055 × FEV1/FVC (r2 = 0.31; adjusted r2 = 0.30). CONCLUSIONS: The correction of TLC and RV results obtained by SBHD can improve the accuracy of this method for assessing lung volumes in patients with OLD. However, additional studies are needed in order to validate these equations. PMID:24473761

  2. A constant-volume rapid exhaust dilution system for motor vehicle particulate matter number and mass measurements.

    PubMed

    Maricq, M Matti; Chase, Richard E; Xu, Ning; Podsiadlik, Diane H

    2003-10-01

    An improved version of the constant volume sampling (CVS) methodology that overcomes a number of obstacles that exist with the current CVS dilution tunnel system used in most diesel and gasoline vehicle emissions test facilities is presented. The key feature of the new sampling system is the introduction of dilution air immediately at the vehicle tailpipe. In the present implementation, this is done concentrically through a cylindrical air filter. Elimination of the transfer hose conventionally used to connect the tailpipe to the dilution tunnel significantly reduces the hydrocarbon and particulate matter (PM) storage release artifacts that can lead to wildly incorrect particle number counts and to erroneous filter-collected PM mass. It provides accurate representations of particle size distributions for diesel vehicles by avoiding the particle coagulation that occurs in the transfer hose. Furthermore, it removes the variable delay time that otherwise exists between the time that emissions exit the tailpipe and when they are detected in the dilution tunnel. The performance of the improved CVS system is examined with respect to diesel, gasoline, and compressed natural gas vehicles. PMID:14604329

  3. STATISTICAL ESTIMATES OF VARIANCE FOR 15N ISOTOPE DILUTION MEASUREMENTS OF GROSS RATES OF NITROGEN CYCLE PROCESSES

    EPA Science Inventory

    It has been fifty years since Kirkham and Bartholmew (1954) presented the conceptual framework and derived the mathematical equations that formed the basis of the now commonly employed method of 15N isotope dilution. Although many advances in methodology and analysis have been ma...

  4. Students' Conception of Infinite Series

    ERIC Educational Resources Information Center

    Martinez-Planell, Rafael; Gonzalez, Ana Carmen; DiCristina, Gladys; Acevedo, Vanessa

    2012-01-01

    This is a report of a study of students' understanding of infinite series. It has a three-fold purpose: to show that students may construct two essentially different notions of infinite series, to show that one of the constructions is particularly difficult for students, and to examine the way in which these two different constructions may be…

  5. Infinitely Large New Dimensions

    SciTech Connect

    Arkani-Hamed, Nima; Dimopoulos, Savas; Dvali, Gia; Kaloper, Nemanja

    1999-07-29

    We construct intersecting brane configurations in Anti-de-Sitter space localizing gravity to the intersection region, with any number n of extra dimensions. This allows us to construct two kinds of theories with infinitely large new dimensions, TeV scale quantum gravity and sub-millimeter deviations from Newton's Law. The effective 4D Planck scale M{sub Pl} is determined in terms of the fundamental Planck scale M{sub *} and the AdS radius of curvature L via the familiar relation M{sub Pl}{sup 2} {approx} M{sub *}{sup 2+n} L{sup n}; L acts as an effective radius of compactification for gravity on the intersection. Taking M{sub *} {approx} TeV and L {approx} sub-mm reproduces the phenomenology of theories with large extra dimensions. Alternately, taking M{sub *} {approx} L{sup -1} {approx} M{sub Pl}, and placing our 3-brane a distance {approx} 100M{sub Pl}{sup -1} away from the intersection gives us a theory with an exponential determination of the Weak/Planck hierarchy.

  6. Science Notes: Dilution of a Weak Acid

    ERIC Educational Resources Information Center

    Talbot, Christopher; Wai, Chooi Khee

    2014-01-01

    This "Science note" arose out of practical work involving the dilution of ethanoic acid, the measurement of the pH of the diluted solutions and calculation of the acid dissociation constant, K[subscript a], for each diluted solution. The students expected the calculated values of K[subscript a] to be constant but they found that the…

  7. Are There Infinite Irrigation Trees?

    NASA Astrophysics Data System (ADS)

    Bernot, M.; Caselles, V.; Morel, J. M.

    2006-08-01

    In many natural or artificial flow systems, a fluid flow network succeeds in irrigating every point of a volume from a source. Examples are the blood vessels, the bronchial tree and many irrigation and draining systems. Such systems have raised recently a lot of interest and some attempts have been made to formalize their description, as a finite tree of tubes, and their scaling laws [25], [26]. In contrast, several mathematical models [5], [22], [10], propose an idealization of these irrigation trees, where a countable set of tubes irrigates any point of a volume with positive Lebesgue measure. There is no geometric obstruction to this infinitesimal model and general existence and structure theorems have been proved. As we show, there may instead be an energetic obstruction. Under Poiseuille law R(s) = s -2 for the resistance of tubes with section s, the dissipated power of a volume irrigating tree cannot be finite. In other terms, infinite irrigation trees seem to be impossible from the fluid mechanics viewpoint. This also implies that the usual principle analysis performed for the biological models needs not to impose a minimal size for the tubes of an irrigating tree; the existence of the minimal size can be proven from the only two obvious conditions for such irrigation trees, namely the Kirchhoff and Poiseuille laws.

  8. Flow-regulated extracorporeal arteriovenous tubing loop for cardiac output measurements by ultrasound velocity dilution: validation in post-cardiac surgery intensive care unit patients.

    PubMed

    Eremenko, Alexsandr A; Safarov, Perviz N

    2010-01-01

    Assessment of cardiac output (CO) is crucial in the management of the critically ill, especially in post cardiac surgery intensive care unit (ICU) patients. In this study, we validated CO measured by the novel ultrasound dilution (COUD) with those measured by pulmonary artery (PA) thermodilution (COTD) in 26 adult post cardiac surgery patients. For COUD, blood was circulated through an extracorporeal arteriovenous (AV) loop from the radial artery catheter to the introducer of PA catheter for 5-8 minutes. Three to four injections of 25 ml body temperature isotonic saline were performed into the venous limb of the AV loop. For COTD, five injections of 10 ml ice cold saline were performed. A total of 77 COUD and COTD measurement sets were compared. Cardiac output measured by thermodilution ranged from 3.28 to 9.4 L/min, whereas COUD ranged from 2.85 to 10.1 L/min. The correlation between the methods was found to be r = 0.91, COUD = 0.93(COTD) + 0.42 L/min. Bias and precision (mean difference ± 2SDs) was -0.004 ± 1.34 L/min between the two methods. The percentage error (2SD/mean) was 22.2%, which is below the clinically acceptable limit (<30%). Cardiac output measured by ultrasound dilution and thermodilution methods agreed well in post cardiac surgery ICU patients and hence can be interchangeably used. PMID:21245798

  9. Thermodynamics of Dilute Solutions.

    ERIC Educational Resources Information Center

    Jancso, Gabor; Fenby, David V.

    1983-01-01

    Discusses principles and definitions related to the thermodynamics of dilute solutions. Topics considered include dilute solution, Gibbs-Duhem equation, reference systems (pure gases and gaseous mixtures, liquid mixtures, dilute solutions), real dilute solutions (focusing on solute and solvent), terminology, standard states, and reference systems.…

  10. Cross-correlation focus method with an electrostatic sensor array for local particle velocity measurement in dilute gas-solid two-phase flow

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Zhang, Jingyu; Gao, Wenbin; Ding, Hongbing; Wu, Weiping

    2015-11-01

    The gas-solid two-phase flow has been widely applied in the power, chemical and metallurgical industries. It is of great significance in the research of gas-solid two-phase flow to measure particle velocity at different locations in the pipeline. Thus, an electrostatic sensor array comprising eight arc-shaped electrodes was designed. The relationship between the cross-correlation (CC) velocity and the distribution of particle velocity, charge density and electrode spatial sensitivity was analysed. Then the CC sensitivity and its calculation method were proposed. According to the distribution of CC sensitivity, it was found that, between different electrode pairs, it had different focus areas. The CC focus method was proposed for particle velocity measurement at different locations and validated by a belt-style electrostatic induction experiment facility. Finally, the particle velocities at different locations with different flow conditions were measured to research the particle velocity distribution in a dilute horizontal pneumatic conveying pipeline.

  11. Reference measurements for total mercury and methyl mercury content in marine biota samples using direct or species-specific isotope dilution inductively coupled plasma mass spectrometry.

    PubMed

    Krata, Agnieszka; Vassileva, Emilia; Bulska, Ewa

    2016-11-01

    The analytical procedures for reference measurements of the total Hg and methyl mercury (MeHg) mass fractions at various concentration levels in marine biota samples, candidates for certified reference materials (oyster and clam Gafrarium tumidum), were evaluated. Two modes of application of isotope dilution inductively coupled plasma mass spectrometry method (ID ICP-MS), namely direct isotope dilution and species-specific isotope dilution analysis with the use of two different quantification mass spectrometry techniques were compared. The entire ID ICP-MS measurement procedure was described by mathematical modelling and the combined uncertainty of measurement results was estimated. All factors influencing the final results as well as isotopic equilibrium were systematically investigated. This included the procedural blank, the moisture content in the biota samples and all factors affecting the blend ratio measurements (instrumental background, spectral interferences, dead time and mass discrimination effects as well as the repeatability of measured isotopic ratios). Modelling of the entire measurement procedures and the use of appropriate certified reference materials enable to assure the traceability of obtained values to the International System of Units (SI): the mole or the kilogram. The total mass fraction of mercury in oyster and clam biota samples, after correction for moisture contents, was found to be: 21.1 (1.1) 10(-9) kg kg(-1) (U =5.1% relative, k=2) and 390.0 (9.4) 10(-9) kg kg(-1) (U=2.4% relative, k=2), respectively. For the determination of mercury being present as methyl mercury, the non-chromatographic separation on anion-exchange resin AG1-X8 of the blended samples was applied. The content of MeHg (as Hg) in oyster sample was found: 4.81 (24) 10(-9)kgkg(-1) (U=5.0%, k=2) and 4.84 (21) 10(-9)kgkg(-1) (U=4.3%, k=2) with the use of quadrupole (ICP QMS) or sector field (ICP SFMS) inductively coupled plasma mass spectrometers, respectively. In the

  12. Infinite dimensional quantum information geometry

    NASA Astrophysics Data System (ADS)

    Grasselli, Matheus R.

    2001-02-01

    We present the construction of an infinite dimensional Banach manifold of quantum mechanical states on a Hilbert space H using different types of small perturbations of a given Hamiltonian H0. We provide the manifold with a flat connection, called the exponential connection, and comment on the possibility of introducing the dual mixture connection

  13. Decoherence in infinite quantum systems

    SciTech Connect

    Blanchard, Philippe; Hellmich, Mario

    2012-09-01

    We review and discuss a notion of decoherence formulated in the algebraic framework of quantum physics. Besides presenting some sufficient conditions for the appearance of decoherence in the case of Markovian time evolutions we provide an overview over possible decoherence scenarios. The framework for decoherence we establish is sufficiently general to accommodate quantum systems with infinitely many degrees of freedom.

  14. Word learning under infinite uncertainty.

    PubMed

    Blythe, Richard A; Smith, Andrew D M; Smith, Kenny

    2016-06-01

    Language learners must learn the meanings of many thousands of words, despite those words occurring in complex environments in which infinitely many meanings might be inferred by the learner as a word's true meaning. This problem of infinite referential uncertainty is often attributed to Willard Van Orman Quine. We provide a mathematical formalisation of an ideal cross-situational learner attempting to learn under infinite referential uncertainty, and identify conditions under which word learning is possible. As Quine's intuitions suggest, learning under infinite uncertainty is in fact possible, provided that learners have some means of ranking candidate word meanings in terms of their plausibility; furthermore, our analysis shows that this ranking could in fact be exceedingly weak, implying that constraints which allow learners to infer the plausibility of candidate word meanings could themselves be weak. This approach lifts the burden of explanation from 'smart' word learning constraints in learners, and suggests a programme of research into weak, unreliable, probabilistic constraints on the inference of word meaning in real word learners. PMID:26927884

  15. Dilutions Made Easy.

    ERIC Educational Resources Information Center

    Kamin, Lawrence

    1996-01-01

    Presents problems appropriate for high school and college students that highlight dilution methods. Promotes an understanding of dilution methods in order to prevent the unnecessary waste of chemicals and glassware in biology laboratories. (JRH)

  16. A unified approach to infinite-dimensional integration

    NASA Astrophysics Data System (ADS)

    Albeverio, S.; Mazzucchi, S.

    2016-04-01

    An approach to infinite-dimensional integration which unifies the case of oscillatory integrals and the case of probabilistic type integrals is presented. It provides a truly infinite-dimensional construction of integrals as linear functionals, as much as possible independent of the underlying topological and measure theoretical structure. Various applications are given, including, next to Feynman path integrals, Schrödinger and diffusion equations, as well as higher order hyperbolic and parabolic equations.

  17. Plutonium carbonate speciation changes as measured in dilute solutions with photoacoustic spectroscopy: Yucca Mountain Site Characterization Program Milestone report 3350

    SciTech Connect

    Tait, C.D.; Ekberg, S.A.; Palmer, P.D.; Morris, D.E.

    1995-05-01

    The stability fields for dilute Pu-carbonate species versus pH (8.4 to 12.0) and total carbonate concentrations (3 mM to 1.0 M) have been mapped-out using photoacoustic absorption spectroscopy (PAS). At least four different plutonium species, characterized by absorption peaks at 486, 492, 500, and 513 rim, have been found. A redox change to a Pu(VI) complex can not account for the speciation change associated with the first two spectra (486 and 492 nm peaks). Moreover, the data are consistent with what is predicted from a previous YMP milestone. This previous study was performed under very different conditions of plutonium concentration and carbonate/pH changes, and extension of these conditions to much lower Pu concentrations and to more neutral pHs was made possible with PAS spectroscopy. These new results reinforce the previous results by extending the range of direct observation and by eliminating other possibilities such as dimerization/polymerization reactions. As bicarbonate concentration is increased from .01 M to 1.0 M at pH=8.4 to 8.9, predominately [Pu(OH){sub x+1}(CO{sub 3}){sub y}]{sup 4-(x+2y)} (492 nm peak) is converted to [Pu(OH){sub x}(CO{sub 3}){sub y+l}]{sup 4-(x+2y+2)} (486 nm peak). The starting stoichiometry (x and y values) remain undetermined, but the effect of ionic strength and temperature indicate that the 486 nm species is highly charged, and therefore x+2y{ge}3. The temperature effect on the equilibrium between these two species was also investigated, with the species giving rise to the 486 nm peak reversibly losing importance at elevated (50 and 75{degrees}C temperatures).

  18. Serial Dilution Simulation Lab

    ERIC Educational Resources Information Center

    Keler, Cynthia; Balutis, Tabitha; Bergen, Kim; Laudenslager, Bryanna; Rubino, Deanna

    2010-01-01

    Serial dilution is often a difficult concept for students to understand. In this short dry lab exercise, students perform serial dilutions using seed beads. This exercise helps students gain skill at performing dilutions without using reagents, bacterial cultures, or viral cultures, while being able to visualize the process.

  19. An Infinite Restricted Boltzmann Machine.

    PubMed

    Côté, Marc-Alexandre; Larochelle, Hugo

    2016-07-01

    We present a mathematical construction for the restricted Boltzmann machine (RBM) that does not require specifying the number of hidden units. In fact, the hidden layer size is adaptive and can grow during training. This is obtained by first extending the RBM to be sensitive to the ordering of its hidden units. Then, with a carefully chosen definition of the energy function, we show that the limit of infinitely many hidden units is well defined. As with RBM, approximate maximum likelihood training can be performed, resulting in an algorithm that naturally and adaptively adds trained hidden units during learning. We empirically study the behavior of this infinite RBM, showing that its performance is competitive to that of the RBM, while not requiring the tuning of a hidden layer size. PMID:27171012

  20. Logic of infinite quantum systems

    NASA Astrophysics Data System (ADS)

    Mundici, Daniele

    1993-10-01

    Limits of sequences of finite-dimensional (AF) C *-algebras, such as the CAR algebra for the ideal Fermi gas, are a standard mathematical tool to describe quantum statistical systems arising as thermodynamic limits of finite spin systems. Only in the infinite-volume limit one can, for instance, describe phase transitions as singularities in the thermodynamic potentials, and handle the proliferation of physically inequivalent Hilbert space representations of a system with infinitely many degrees of freedom. As is well known, commutative AF C *-algebras correspond to countable Boolean algebras, i.e., algebras of propositions in the classical two-valued calculus. We investigate the noncommutative logic properties of general AF C *-algebras, and their corresponding systems. We stress the interplay between Gödel incompleteness and quotient structures in the light of the “nature does not have ideals” program, stating that there are no quotient structures in physics. We interpret AF C *-algebras as algebras of the infinite-valued calculus of Lukasiewicz, i.e., algebras of propositions in Ulam's “ twenty questions” game with lies.

  1. On the Physical Meaning of the Isothermal Titration Calorimetry Measurements in Calorimeters with Full Cells

    PubMed Central

    Grolier, Jean-Pierre E.; del Río, Jose Manuel

    2009-01-01

    We have performed a detailed study of the thermodynamics of the titration process in an isothermal titration calorimeter with full cells. We show that the relationship between the enthalpy and the heat measured is better described in terms of the equation Δ H = Winj + Q (where Winj is the work necessary to carry out the titration) than in terms of ΔH = Q. Moreover, we show that the heat of interaction between two components is related to the partial enthalpy of interaction at infinite dilution of the titrant component, as well as to its partial volume of interaction at infinite dilution. PMID:20054472

  2. On the physical meaning of the isothermal titration calorimetry measurements in calorimeters with full cells.

    PubMed

    Grolier, Jean-Pierre E; del Río, Jose Manuel

    2009-12-01

    We have performed a detailed study of the thermodynamics of the titration process in an isothermal titration calorimeter with full cells. We show that the relationship between the enthalpy and the heat measured is better described in terms of the equation Delta H = W(inj) + Q (where W(inj) is the work necessary to carry out the titration) than in terms of DeltaH = Q. Moreover, we show that the heat of interaction between two components is related to the partial enthalpy of interaction at infinite dilution of the titrant component, as well as to its partial volume of interaction at infinite dilution. PMID:20054472

  3. Teleportation schemes in infinite dimensional Hilbert spaces

    SciTech Connect

    Fichtner, Karl-Heinz; Freudenberg, Wolfgang; Ohya, Masanori

    2005-10-01

    The success of quantum mechanics is due to the discovery that nature is described in infinite dimension Hilbert spaces, so that it is desirable to demonstrate the quantum teleportation process in a certain infinite dimensional Hilbert space. We describe the teleportation process in an infinite dimensional Hilbert space by giving simple examples.

  4. Microfluidic serial dilution ladder.

    PubMed

    Ahrar, Siavash; Hwang, Michelle; Duncan, Philip N; Hui, Elliot E

    2014-01-01

    Serial dilution is a fundamental procedure that is common to a large number of laboratory protocols. Automation of serial dilution is thus a valuable component for lab-on-a-chip systems. While a handful of different microfluidic strategies for serial dilution have been reported, approaches based on continuous flow mixing inherently consume larger amounts of sample volume and chip real estate. We employ valve-driven circulatory mixing to address these issues and also introduce a novel device structure to store each stage of the dilution process. The dilution strategy is based on sequentially mixing the rungs of a ladder structure. We demonstrate a 7-stage series of 1 : 1 dilutions with R(2) equal to 0.995 in an active device area of 1 cm(2). PMID:24231765

  5. Existing and emerging technologies for measuring stable isotope labelled retinol in biological samples: isotope dilution analysis of body retinol stores.

    PubMed

    Preston, Tom

    2014-01-01

    This paper discusses some of the recent improvements in instrumentation used for stable isotope tracer measurements in the context of measuring retinol stores, in vivo. Tracer costs, together with concerns that larger tracer doses may perturb the parameter under study, demand that ever more sensitive mass spectrometric techniques are developed. GCMS is the most widely used technique. It has high sensitivity in terms of sample amount and uses high resolution GC, yet its ability to detect low isotope ratios is limited by background noise. LCMSMS may become more accessible for tracer studies. Its ability to measure low level stable isotope tracers may prove superior to GCMS, but it is isotope ratio MS (IRMS) that has been designed specifically for low level stable isotope analysis through accurate analysis of tracer:tracee ratios (the tracee being the unlabelled species). Compound-specific isotope analysis, where GC is interfaced to IRMS, is gaining popularity. Here, individual 13C-labelled compounds are separated by GC, combusted to CO2 and transferred on-line for ratiometric analysis by IRMS at the ppm level. However, commercially-available 13C-labelled retinol tracers are 2 - 4 times more expensive than deuterated tracers. For 2H-labelled compounds, GC-pyrolysis-IRMS has now become more generally available as an operating mode on the same IRMS instrument. Here, individual compounds are separated by GC and pyrolysed to H2 at high temperature for analysis by IRMS. It is predicted that GC-pyrolysis-IRMS will facilitate low level tracer procedures to measure body retinol stores, as has been accomplished in the case of fatty acids and amino acids. Sample size requirements for GC-P-IRMS may exceed those of GCMS, but this paper discusses sample preparation procedures and predicts improvements, particularly in the efficiency of sample introduction. PMID:25537104

  6. Measurement of (5'R)- and (5'S)-8,5'-cyclo-2'-deoxyadenosines in DNA in vivo by liquid chromatography/isotope-dilution tandem mass spectrometry

    SciTech Connect

    Jaruga, Pawel; Xiao, Yan; Nelson, Bryant C.; Dizdaroglu, Miral

    2009-09-04

    Oxidatively induced DNA lesions (5'R)- and (5'S)-8,5'-cyclo-2'-deoxyadenosines (R-cdA and S-cdA) are detectable and accumulate in vivo due to disease states and defects in DNA repair. They block transcription and inhibit gene expression, and may play a role in disease processes. Accurate measurement of these lesions in DNA in vivo is necessary to understand their biological effects. We report on a methodology using liquid chromatography/isotope-dilution tandem mass spectrometry to measure R-cdA and S-cdA in DNA. This methodology permitted the detection of these compounds at a level of 0.1 fmol on-column. Levels of R-cdA and S-cdA in mouse liver DNA amounted to 0.133 {+-} 0.024 and 0.498 {+-} 0.065 molecules/10{sup 7} DNA 2'-deoxynucleosides, respectively. The successful measurement of R-cdA and S-cdA in DNA in vivo suggests that this methodology will be used for understanding of their repair and biological consequences, and that these compounds may be used as putative biomarkers for disease states.

  7. Simultaneous measurements of the torsional oscillator and shear modulus of solid 4He diluted with various 3He concentration

    NASA Astrophysics Data System (ADS)

    Shin, Jaeho; Choi, Wonsuk; Choi, Jaewon; Jang, Seong; Shirahama, Keiya; Kim, Eunseong

    2013-03-01

    In 2004, Kim and Chan observed the non-classical rotational inertia (NCRI) of solid helium-4 by using a torsional oscillator (TO). Below 200mK, the resonance period of solid helium dropped, which was originally interpreted as the mass decoupling of the fraction of solid helium. Recently, anomalous increase in the shear modulus of solid helium was found and showed striking similarity in temperature, frequency, 3He concentration, and drive dependence to those of the NCRI. To understand the connection between the NCRI and the shear modulus anomaly, we simultaneously measure the change in the resonance frequency and the stiffness of solid helium below 200mK. The torsion cell contains a pair of the concentric piezoelectric transducers (PZT) which defines an annular channel for the simultaneous measurements. We will report the interference between the motion of the TO at resonance and AC motion of the PZT in solid 4He with different 3He concentration. We gratefully acknowledge the financial support by the National Research Foundation of Korea through the Creative Research Initiatives.

  8. Sparse Bayesian infinite factor models

    PubMed Central

    Bhattacharya, A.; Dunson, D. B.

    2011-01-01

    We focus on sparse modelling of high-dimensional covariance matrices using Bayesian latent factor models. We propose a multiplicative gamma process shrinkage prior on the factor loadings which allows introduction of infinitely many factors, with the loadings increasingly shrunk towards zero as the column index increases. We use our prior on a parameter-expanded loading matrix to avoid the order dependence typical in factor analysis models and develop an efficient Gibbs sampler that scales well as data dimensionality increases. The gain in efficiency is achieved by the joint conjugacy property of the proposed prior, which allows block updating of the loadings matrix. We propose an adaptive Gibbs sampler for automatically truncating the infinite loading matrix through selection of the number of important factors. Theoretical results are provided on the support of the prior and truncation approximation bounds. A fast algorithm is proposed to produce approximate Bayes estimates. Latent factor regression methods are developed for prediction and variable selection in applications with high-dimensional correlated predictors. Operating characteristics are assessed through simulation studies, and the approach is applied to predict survival times from gene expression data. PMID:23049129

  9. Measurement of Interfacial Undercooling in a Dilute Pb-Sn Alloy Near the Regime of Morphological Instability

    NASA Technical Reports Server (NTRS)

    Sen, S.; Dhindaw, B. K.; Peters, P.; Curreri, P.; Kaukler, W. F.

    1998-01-01

    The solid/liquid (s/1) interfacial Seebeck technique was used to measure interfacial undercooling in a Pb-1 wt.% Sn alloy. For plane front solidification an undercooling in the range of 0.54-0.57C was recorded. However, for growth velocities between 6 to 15 micron/s the undercooling, increased with increase in velocity. 'Tbis is in contradiction to the theoretical predictions based on growth at the extremum condition. A modified analytical expression was developed based on the maro,,inal stability criterion to predict undercooling for growth velocities immediately over the limit of morphological stability. Between 6 to 15 microns/s the trend predicted by this modified expression is in qualitative agreement with the experimental results. This model is more consistent with the analysis of Venugopal and Kirkaldy which states that the extremum condition criterion is not applicable in the marginal stability regime. At higher growth velocities between 20 and 50 microns/s where stable cellular growth is expected the undercooling, decreased with increase in velocity. The predictions of Burden and Hunt based on extremum criterion agree reasonably well with the experimental results in this velocity range. Finally, the importance of non-equilibrium phase diagram parameters such as partition coefficient and liquidus slope were also evaluated using the experimental undercooling results obtained in this investigation.

  10. Measurement of intact sulfate and glucuronide phytoestrogen conjugates in human urine using isotope dilution liquid chromatography-tandem mass spectrometry with [13C(3)]isoflavone internal standards.

    PubMed

    Clarke, Don B; Lloyd, Antony S; Botting, Nigel P; Oldfield, Mark F; Needs, Paul W; Wiseman, Helen

    2002-10-01

    A method has been developed for the analysis of phytoestrogens and their conjugates in human urine using liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Stable isotopically labeled [13C(3)]daidzein and [13C(3)]genistein were synthesized and used as internal standards for isotope dilution mass spectrometry. Free aglycons and intact glucuronide, sulfate, diglucuronide, disulfate, and mixed sulfoglucuronide conjugates of isoflavones and lignans were observed in naturally incurred urine samples. Sample pretreatment was not necessary, other than addition of internal standards and pH adjustment. Urine was injected directly onto the analytical column. The limits of detection were generally <50ng/ml, precision was generally <10% CV for conjugates. Total hydrolyzed daidzein and genistein were measured against quality assurance urine sample and were accurate to within 12%. The accuracy of conjugate measurement can not be ascertained, as no reference samples are available. The mean sum of daidzein and its conjugates was within 20% of the hydrolyzed value. Concentrations of the free aglycons of up to 22% of genistein and 18% of daidzein were observed. The average pattern was ca. 54% 7-glucuronide, 25% 4(')-glucuronide, 13% monosulfates, 7% free daidzein, 0.9% sulfoglucuronides, 0.4% diglucuronide, and <0.1% disulfate. Selective enzymatic deconjugation with glucuronidase and mixed glucuronidase/sulfatase were used to validate the accuracy of the quantitation of the intact daidzein conjugates. There were no apparent sex differences, or conditioning effects on the conjugation profile of isoflavones after chronic dosing. PMID:12381375

  11. Addiction to MTH1 protein results in intense expression in human breast cancer tissue as measured by liquid chromatography-isotope-dilution tandem mass spectrometry.

    PubMed

    Coskun, Erdem; Jaruga, Pawel; Jemth, Ann-Sofie; Loseva, Olga; Scanlan, Leona D; Tona, Alessandro; Lowenthal, Mark S; Helleday, Thomas; Dizdaroglu, Miral

    2015-09-01

    MTH1 protein sanitizes the nucleotide pool so that oxidized 2'-deoxynucleoside triphosphates (dNTPs) cannot be used in DNA replication. Cancer cells require MTH1 to avoid incorporation of oxidized dNTPs into DNA that results in mutations and cell death. Inhibition of MTH1 eradicates cancer, validating MTH1 as an anticancer target. By overexpressing MTH1, cancer cells may mediate cancer growth and resist therapy. To date, there is unreliable evidence suggesting that MTH1 is increased in cancer cells, and available methods to measure MTH1 levels are indirect and semi-quantitative. Accurate measurement of MTH1 in disease-free tissues and malignant tumors of patients may be essential for determining if the protein is truly upregulated in cancers, and for the development and use of MTH1 inhibitors in cancer therapy. Here, we present a novel approach involving liquid chromatography-isotope-dilution tandem mass spectrometry to positively identify and accurately quantify MTH1 in human tissues. We produced full length (15)N-labeled MTH1 and used it as an internal standard for the measurements. Following trypsin digestion, seven tryptic peptides of both MTH1 and (15)N-MTH1 were identified by their full scan and product ion spectra. These peptides provided a statistically significant protein score that would unequivocally identify MTH1. Next, we identified and quantified MTH1 in human disease-free breast tissues and malignant breast tumors, and in four human cultured cell lines, three of which were cancer cells. Extreme expression of MTH1 in malignant breast tumors was observed, suggesting that cancer cells are addicted to MTH1 for their survival. The approach described is expected to be applicable to the measurement of MTH1 levels in malignant tumors vs. surrounding disease-free tissues in cancer patients. This attribute may help develop novel treatment strategies and MTH1 inhibitors as potential drugs, and guide therapies. PMID:26202347

  12. Entanglement entropy at infinite-randomness fixed points in higher dimensions.

    PubMed

    Lin, Yu-Cheng; Iglói, Ferenc; Rieger, Heiko

    2007-10-01

    The entanglement entropy of the two-dimensional random transverse Ising model is studied with a numerical implementation of the strong-disorder renormalization group. The asymptotic behavior of the entropy per surface area diverges at, and only at, the quantum phase transition that is governed by an infinite-randomness fixed point. Here we identify a double-logarithmic multiplicative correction to the area law for the entanglement entropy. This contrasts with the pure area law valid at the infinite-randomness fixed point in the diluted transverse Ising model in higher dimensions. PMID:17930713

  13. Quantitative measurement of odor detection thresholds using an air dilution olfactometer, and association with genetic variants in a sample of diverse ancestry

    PubMed Central

    Cook, Gillian R.; Krithika, S; Edwards, Melissa; Kavanagh, Paula

    2014-01-01

    Genetic association studies require a quantitative and reliable method for odor threshold assessment in order to examine the contribution of genetic variants to complex olfactory phenotypes. Our main goal was to assess the feasibility of a portable Scentroid air dilution olfactometer for use in such studies. Using the Scentroid SM110C and the SK5 n-butanol Sensitivity Kit (IDES Canada Inc.), n-butanol odor thresholds were determined for 182 individuals of diverse ancestry (mean age: 20.4 ± 2.5 years; n = 128 female; n = 54 male). Threshold scores from repeat participants were used to calculate a test–retest reliability coefficient, which was statistically significant (r = 0.754, p < 0.001, n = 29), indicating that the Scentroid provides reliable estimates of odor thresholds. In addition, we performed a preliminary genetic analysis evaluating the potential association of n-butanol odor thresholds to six single-nucleotide polymorphisms (SNPs) putatively involved in general olfactory sensitivity (GOS). The results of multiple linear regression analysis revealed no significant association between the SNPs tested and threshold scores. However, our sample size was relatively small, and our study was only powered to identify genetic markers with strong effects on olfactory sensitivity. Overall, we find that the Scentroid provides reliable quantitative measures of odor detection threshold and is well suited for genetic studies of olfactory sensitivity. PMID:25392755

  14. Precision of glucose measurements in control sera by isotope dilution/mass spectrometry: proposed definitive method compared with a reference method

    SciTech Connect

    Pelletier, O.; Arratoon, C.

    1987-08-01

    This improved isotope-dilution gas chromatographic/mass spectrometric (GC/MS) method, in which (/sup 13/C)glucose is the internal standard, meets the requirements of a Definitive Method. In a first study with five reconstituted lyophilized sera, a nested analysis of variance of GC/MS values indicated considerable among-vial variation. The CV for 32 measurements per serum ranged from 0.5 to 0.9%. However, concentration and uncertainty values (mmol/L per gram of serum) assigned to one serum by the NBS Definitive Method (7.56 +/- 0.28) were practically identical to those obtained with the proposed method (7.57 +/- 0.20). In the second study, we used twice more (/sup 13/C)glucose diluent to assay four serum pools and two lyophilized sera. The CV ranged from 0.26 to 0.5% for the serum pools and from 0.28 to 0.59% for the lyophilized sera. In comparison, results by the hexokinase/glucose-6-phosphate dehydrogenase reference method agreed within acceptable limits with those by the Definitive Method but tended to be slightly higher (up to 3%) for lyophilized serum samples or slightly lower (up to 2.5%) for serum pools.

  15. Body composition of adult cystic fibrosis patients and control subjects as determined by densitometry, bioelectrical impedance, total-body electrical conductivity, skinfold measurements, and deuterium oxide dilution

    SciTech Connect

    Newby, M.J.; Keim, N.L.; Brown, D.L. )

    1990-08-01

    This study contrasts body compositions (by six methods) of eight cystic fibrosis (CF) subjects with those of eight control subjects matched for age, height, and sex. CF subjects weighed 84% as much as control subjects. Densitometry and two bioelectrical impedance-analysis methods suggested that reduced CF weights were due to less lean tissue (10.7, 9.5, and 10.4 kg). Total-body electrical conductivity (TOBEC) and skinfold-thickness measurements indicated that CF subjects were leaner than control subjects and had less fat (5.4 and 3.6 kg) and less lean (5.2 and 7 kg) tissue. D2O dilution showed a pattern similar to TOBEC (8.3 kg less lean, 2.7 kg less fat tissue). Densitometry estimates of fat (mass and percent) were not correlated (r less than 0.74, p greater than 0.05) with any other method for CF subjects but were correlated with all other methods for control subjects. CF subjects contained less fat and lean tissue than did control subjects. Densitometry by underwater weighing is unsuitable for assessing body composition of CF patients.

  16. Measurement of attogram quantities of 231Pa in dissolved and particulate fractions of seawater by isotope dilution thermal ionization mass spectroscopy.

    PubMed

    Shen, Chuan-Chou; Cheng, Hai; Edwards, R Lawrence; Moran, S Bradley; Edmonds, Henrietta N; Hoff, John A; Thomas, Rebecca B

    2003-03-01

    A technique has been developed to quantify ultratrace 231Pa (50-2000 ag; 1 ag = 10(-18) g) concentrations in seawater using isotope-dilution thermal ionization mass spectrometry (TIMS). The method is a modification of a process developed by Pickett et al. (Pickett, D. A.; Murrell, M. T.; Williams, R. W. Anal. Chem. 1994, 66, 1044-1049) and extends the technique to very low levels of protactinium. The procedural blank is 16 +/- 15 ag (2sigma), and the ionization efficiency (ions generated/atom loaded) approaches 0.5%. Measurement time is <1 h. The amount of 231Pa needed to produce 231Pa data with an uncertainty of +/-4-12% is 100-1000 ag (approximately 3 x 10(5) to 3 x 10(6) atoms). Replicate measurements made on known standards and seawater samples demonstrate that the analytical precision approximates that expected from counting statistics and that, based on detection limits of 38 and 49 ag, protactinium can be detected in a minimum sample size of surface seawater of approximately 2 L for suspended particulate matter and <0.1 L for filtered (<0.4 microm) seawater, respectively. The concentration of 231Pa (tens of attograms per liter) can be determined with an uncertainty of +/-5-10% (2sigma) for suspended particulate matter filtered from 5 to 10 L of seawater. For the dissolved fraction, 0.5-1 L of seawater yields 231Pa measurements with a precision of 1-10%. Sample size requirements are orders of magnitude less than traditional decay-counting techniques and significantly less than previously reported ICP-MS techniques. Our technique can also be applied to other environmental samples, including cave waters, rivers, and igneous rocks. PMID:12641225

  17. [The measurement of extra vascular lung water using a thermal-sodium double indicator dilution technique in patients undergoing surgery for esophageal cancer].

    PubMed

    Watanabe, A; Kusajima, K; Kawaharada, N; Komatsu, K; Sugimoto, S; Doi, H; Tanaka, A; Takeda, H; Mishina, H; Komatsu, S

    1990-11-01

    The Extra Vascular Lung Water (EVLW) was measured using the thermal sodium double indicator dilution technique in 21 patients undergoing surgery for esophageal cancer. This measurement is an important parameter in the control of the respiratory function. In the 16 cases without pulmonary complications, the preoperative EVLW was 5.3 +/- 0.2 (mean +/- SEM) ml/kg and the immediate postoperative EVLW was 4.8 +/- 0.4 ml/kg. This change was significant (p less than 0.05), but within 24 hours the EVLW returned to almost the same levels as those recorded before surgery. In only 3 cases, the EVLW were elevated beyond 7.5 ml/kg, but these high EVLW levels did not continue for more than 12 hours. Of the 5 patients with pulmonary complications, only two experienced pulmonary edema. Their preoperative EVLW levels were normal, but the immediate postoperative EVLW levels were significantly elevated beyond 10 ml/kg. These elevated levels were observed before the PaO2, the portable chest roentgenograms and the other test results changed following surgery. The high EVLW levels beyond 7.5 ml/kg continued for 72 hours after surgery. We found no correlation between the EVLW and measureable hemodynamic parameters (Cardiac Index, Pulmonary Wedge Pressure, Colloid Osmotic Pressure-Pulmonary Wedge Pressure gradient) during the observation period. In the other cases with pulmonary complications (2 cases were pneumonia, one was atelectasis with pneumonia), the changes in the EVLW levels were the same as for the cases without pulmonary complications. These results indicate that the EVLW is the optimum parameter for the control of the respiratory function and early diagnosis of pulmonary edema after surgery for esophageal cancer. PMID:2280095

  18. Blood volume and red cell mass in children with moderate and severe malaria measured by chromium-53 dilution and gas chromatography/mass spectrometric analysis.

    PubMed

    Macallan, Derek C; Abaye, Daniel A; Dottin, Simone; Onanga, Myriam; Kombila, Maryvonne; Dzeing-Ella, Arnaud; Kremsner, Peter G; Krishna, Sanjeev; Planche, Timothy

    2009-08-30

    Understanding blood volume changes in children with malaria is important for managing fluid status. Traditionally, blood/red cell volume measurements have used radioactive chromium isotopes. We applied an alternative approach, using non-radioactive chromium-53 labelling and mass spectrometry to investigate red cell volume (RCV) in Gabonese children with malaria. Nineteen children with malaria participated (10 severe, 9 moderately severe; ages 15 months to 7 years). Blood labelled with (53)Cr-chromate ex vivo was re-injected, then sampled 30 min later. Pre- and post-injection (53)Cr content were measured by gas chromatography/electron ionisation mass spectrometry of the chromium-trifluoroacetylacetone (TFA) chelate, calibrated against (50)Cr standards. Blood and red cell volumes were calculated from isotopic dilution in 15 of 19 children (in four, insufficient signal mitigated analysis). In this small pilot study, there were no significant differences between moderate and severe cases. Including all subjects, the mean RCV was reduced compared with predicted values (184 vs. 269 mL; p = 0.016) but blood volume, 71 +/- 33 mL/kg (normalised for weight), was close to predicted, approximately 77 mL/kg, commensurate with reduced haematocrit. Blood lactate concentration correlated negatively with RCV/weight (r = -0.56, p = 0.028), consistent with anaemia. In one case, sequential samples over 42 days gave an estimated rate of (53)Cr disappearance of 1.4%/day (equivalent half-life: 70 days). (53)Cr-labelling of red cells may be used to estimate blood and red cell volumes and can be used as an investigative tool in situations such as childhood diseases and resource-constrained settings. Although the red cell mass is depleted in malaria, the blood volume appears relatively well preserved. PMID:19603467

  19. Isotope dilution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Heumann, Klaus G.

    1992-09-01

    In the past isotope dilution mass spectrometry (IDMS) has usually been applied using the formation of positive thermal ions of metals. Especially in calibrating other analytical methods and for the certification of standard reference materials this type of IDMS became a routine method. Today, the progress in this field lies in the determination of ultra trace amounts of elements, e.g. of heavy metals in Antarctic ice and in aerosols in remote areas down to the sub-pg g-1 and sub-pg m-3 levels respectively, in the analysis of uranium and thorium at concentrations of a few pg g-1 in sputter targets for the production of micro- electronic devices or in the determination of sub-picogram amounts of230Th in corals for geochemical age determinations and of226Ra in rock samples. During the last few years negative thermal ionization IDMS has become a frequently used method. The determination of very small amounts of selenium and technetium as well as of other transition metals such as vanadium, chromium, molybdenum and tungsten are important examples in this field. Also the measurement of silicon in connection with a re-determination of Avogadro's number and osmium analyses for geological age determinations by the Re/Os method are of special interest. Inductively-coupled plasma mass spectrometry is increasingly being used for multi-element analyses by the isotope dilution technique. Determinations of heavy metals in samples of marine origin are representative examples for this type of multi-element analysis by IDMS. Gas chromatography-mass spectrometry systems have also been successfully applied after chelation of metals (for example Pt determination in clinical samples) or for the determination of volatile element species in the environment, e.g. dimethyl sulfide. However, IDMS--specially at low concentration levels in the environment--seems likely to be one of the most powerful analytical methods for speciation in the future. This has been shown, up to now, for species of

  20. Envisioning the Infinite by Projecting Finite Properties

    ERIC Educational Resources Information Center

    Ely, Robert

    2011-01-01

    We analyze interviews with 24 post-secondary students as they reason about infinite processes in the context of the tricky Tennis Ball Problem. By metaphorically projecting various properties from the finite states such as counting and indexing, participants envisioned widely varying final states for the infinite process. Depending on which…

  1. Improving the Instruction of Infinite Series

    ERIC Educational Resources Information Center

    Lindaman, Brian; Gay, A. Susan

    2012-01-01

    Calculus instructors struggle to teach infinite series, and students have difficulty understanding series and related concepts. Four instructional strategies, prominently used during the calculus reform movement, were implemented during a 3-week unit on infinite series in one class of second-semester calculus students. A description of each…

  2. Inspiring Examples in Rearrangements of Infinite Products

    ERIC Educational Resources Information Center

    Ramasinghe, W.

    2007-01-01

    It is well known that simple examples are really encouraging in the understanding of rearrangements of infinite series. In this paper a similar role is played by simple examples in the case of infinite products. Iterated products of double products seem to have a similar spirit of rearrangements of products, although they are not the same.…

  3. Orthogonality preserving infinite dimensional quadratic stochastic operators

    SciTech Connect

    Akın, Hasan; Mukhamedov, Farrukh

    2015-09-18

    In the present paper, we consider a notion of orthogonal preserving nonlinear operators. We introduce π-Volterra quadratic operators finite and infinite dimensional settings. It is proved that any orthogonal preserving quadratic operator on finite dimensional simplex is π-Volterra quadratic operator. In infinite dimensional setting, we describe all π-Volterra operators in terms orthogonal preserving operators.

  4. Understanding the Behaviour of Infinite Ladder Circuits

    ERIC Educational Resources Information Center

    Ucak, C.; Yegin, K.

    2008-01-01

    Infinite ladder circuits are often encountered in undergraduate electrical engineering and physics curricula when dealing with series and parallel combination of impedances, as a part of filter design or wave propagation on transmission lines. The input impedance of such infinite ladder circuits is derived by assuming that the input impedance does…

  5. Infinite sets and double binds.

    PubMed

    Arden, M

    1984-01-01

    There have been many attempts to bring psychoanalytical theory up to date. This paper approaches the problem by discussing the work of Gregory Bateson and Ignacio Matte-Blanco, with particular reference to the use made by these authors of Russell's theory of logical types. Bateson's theory of the double bind and Matte-Blanco's bilogic are both based on concepts of logical typing. It is argued that the two theories can be linked by the idea that neurotic symptoms are based on category errors in thinking. Clinical material is presented from the analysis of a middle-aged woman. The intention is to demonstrate that the process of making interpretations can be thought of as revealing errors in thinking. Changes in the patient's inner world are then seen to be the result of clarifying childhood experiences based on category errors. Matte-Blanco's theory of bilogic and infinite experiences is a re-evaluation of the place of the primary process in mental life. It is suggested that a combination of bilogic and double bind theory provides a possibility of reformulating psychoanalytical theory. PMID:6544755

  6. Simultaneous Measurement of Tabun, Sarin, Soman, Cyclosarin, VR, VX, and VM Adducts to Tyrosine in Blood Products by Isotope Dilution UHPLC-MS/MS

    PubMed Central

    Crow, Brian S.; Pantazides, Brooke G.; Quiñones-González, Jennifer; Garton, Joshua W.; Carter, Melissa D.; Perez, Jonas W.; Watson, Caroline M.; Tomcik, Dennis J.; Crenshaw, Michael D.; Brewer, Bobby N.; Riches, James R.; Stubbs, Sarah J.; Read, Robert W.; Evans, Ronald A.; Thomas, Jerry D.; Blake, Thomas A.; Johnson, Rudolph C.

    2015-01-01

    This work describes a new specific, sensitive, and rapid stable isotope dilution method for the simultaneous detection of the organophosphorus nerve agents (OPNAs) tabun (GA), sarin (GB), soman (GD), cyclosarin (GF), VR, VX, and VM adducts to tyrosine (Tyr). Serum, plasma, and lysed whole blood samples (50 µL) were prepared by protein precipitation followed by digestion with Pronase. Specific Tyr adducts were isolated from the digest by a single solid phase extraction (SPE) step, and the analytes were separated by reversed-phase ultra high performance liquid chromatography (UHPLC) gradient elution in less than 2 min. Detection was performed on a triple quadrupole tandem mass spectrometer using time-triggered selected reaction monitoring (SRM) in positive electrospray ionization (ESI) mode. The calibration range was characterized from 0.100–50.0 ng/mL for GB– and VR– Tyr and 0.250–50.0 ng/mL for GA–, GD–, GF–, and VX/VM–Tyr (R2 ≥ 0.995). Inter- and intra-assay precision had coefficients of variation of ≤17 and ≤10%, respectively, and the measured concentration accuracies of spiked samples were within 15% of the targeted value for multiple spiking levels. The limit of detection was calculated to be 0.097, 0.027, 0.018, 0.074, 0.023, and 0.083 ng/mL for GA–, GB–, GD–, GF–, VR–, and VX/VM–Tyr, respectively. A convenience set of 96 serum samples with no known nerve agent exposure was screened and revealed no baseline values or potential interferences. This method provides a simple and highly specific diagnostic tool that may extend the time postevent that a confirmation of nerve agent exposure can be made with confidence. PMID:25286390

  7. Simultaneous measurement of tabun, sarin, soman, cyclosarin, VR, VX, and VM adducts to tyrosine in blood products by isotope dilution UHPLC-MS/MS.

    PubMed

    Crow, Brian S; Pantazides, Brooke G; Quiñones-González, Jennifer; Garton, Joshua W; Carter, Melissa D; Perez, Jonas W; Watson, Caroline M; Tomcik, Dennis J; Crenshaw, Michael D; Brewer, Bobby N; Riches, James R; Stubbs, Sarah J; Read, Robert W; Evans, Ronald A; Thomas, Jerry D; Blake, Thomas A; Johnson, Rudolph C

    2014-10-21

    This work describes a new specific, sensitive, and rapid stable isotope dilution method for the simultaneous detection of the organophosphorus nerve agents (OPNAs) tabun (GA), sarin (GB), soman (GD), cyclosarin (GF), VR, VX, and VM adducts to tyrosine (Tyr). Serum, plasma, and lysed whole blood samples (50 μL) were prepared by protein precipitation followed by digestion with Pronase. Specific Tyr adducts were isolated from the digest by a single solid phase extraction (SPE) step, and the analytes were separated by reversed-phase ultra high performance liquid chromatography (UHPLC) gradient elution in less than 2 min. Detection was performed on a triple quadrupole tandem mass spectrometer using time-triggered selected reaction monitoring (SRM) in positive electrospray ionization (ESI) mode. The calibration range was characterized from 0.100-50.0 ng/mL for GB- and VR-Tyr and 0.250-50.0 ng/mL for GA-, GD-, GF-, and VX/VM-Tyr (R(2) ≥ 0.995). Inter- and intra-assay precision had coefficients of variation of ≤17 and ≤10%, respectively, and the measured concentration accuracies of spiked samples were within 15% of the targeted value for multiple spiking levels. The limit of detection was calculated to be 0.097, 0.027, 0.018, 0.074, 0.023, and 0.083 ng/mL for GA-, GB-, GD-, GF-, VR-, and VX/VM-Tyr, respectively. A convenience set of 96 serum samples with no known nerve agent exposure was screened and revealed no baseline values or potential interferences. This method provides a simple and highly specific diagnostic tool that may extend the time postevent that a confirmation of nerve agent exposure can be made with confidence. PMID:25286390

  8. Route of tracer administration does not affect ileal endogenous nitrogen recovery measured with the 15N-isotope dilution technique in pigs fed rapidly digestible diets.

    PubMed

    Steendam, C A Carina; Verstegen, Martin W A; Tamminga, Seerp; Boer, Huug; van 't End, Marianne; Verstappen, Berthe; Caine, William R; Visser, G Henk

    2004-11-01

    The (15)N-isotope dilution technique ((15)N-IDT), with either pulse-dose oral administration or continuous i.v. administration of [(15)N]-l-leucine (carotid artery), both at 5 mg/(kg body weight . d), was used to measure ileal (postvalve T-cecum cannula) endogenous nitrogen recovery (ENR) in pigs (9 +/- 0.6 kg). Diets were cornstarch, enzyme-hydrolyzed casein with no (control) or high (4%) content of quebracho extract (Schinopsis spp.) rich in condensed tannins. Blood was sampled from a catheter in the external jugular vein. Mean plasma (15)N-enrichment at d 8-10 was higher (P = 0.0009) after i.v. than after oral administration [0.0356 vs. 0.0379 atom% excess (APE)]. Plasma (15)N-enrichment for i.v. infused pigs was 0.01117 APE higher (P < 0.0001) and for orally dosed pigs 0.0081 APE lower (P < 0.0001) at 11 h postprandial compared with 1 h postprandial. Apparent ileal N digestibility was higher (P < 0.0001) for the control (85.5%) than for the quebracho diet (69.5%). ENR was calculated from the ratio of (15)N-enrichment of plasma and digesta. The ENR for the quebracho diet was approximately 300% higher than for the control diet (6.03 vs. 1.94 g/kg dry matter intake, P < 0.001). The real N digestibility (92.2 +/- 0.4%) was equal for both diets (P = 0.1030) and both tracer methods (P = 0.9730). We concluded that oral administration of [(15)N]leucine provides reasonable estimates of ENR in pigs fed semipurified diets with high or low content of tannins; however, one must be careful in extrapolating this conclusion to studies with other protein sources or feeding frequencies. PMID:15514277

  9. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... meter, a thermal-mass meter, an averaging Pitot tube, or a hot-wire anemometer. (c) Flow conditioning... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Dilution air and diluted exhaust flow...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related...

  10. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... meter, a thermal-mass meter, an averaging Pitot tube, or a hot-wire anemometer. (c) Flow conditioning... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Dilution air and diluted exhaust flow...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related...

  11. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... meter, a thermal-mass meter, an averaging Pitot tube, or a hot-wire anemometer. (c) Flow conditioning... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Dilution air and diluted exhaust flow...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related...

  12. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... meter, a thermal-mass meter, an averaging Pitot tube, or a hot-wire anemometer. (c) Flow conditioning... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Dilution air and diluted exhaust flow...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related...

  13. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... meter, a thermal-mass meter, an averaging Pitot tube, or a hot-wire anemometer. (c) Flow conditioning... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Dilution air and diluted exhaust flow...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related...

  14. A candidate reference measurement procedure for quantifying serum concentrations of 25-hydroxyvitamin D₃ and 25-hydroxyvitamin D₂ using isotope-dilution liquid chromatography-tandem mass spectrometry.

    PubMed

    Mineva, Ekaterina M; Schleicher, Rosemary L; Chaudhary-Webb, Madhulika; Maw, Khin L; Botelho, Julianne C; Vesper, Hubert W; Pfeiffer, Christine M

    2015-07-01

    The inaccuracy of routine serum 25-hydroxyvitamin D measurements hampers the interpretation of data in patient care and public health research. We developed and validated a candidate reference measurement procedure (RMP) for highly accurate quantitation of two clinically important 25-hydroxyvitamin D metabolites in serum, 25-hydroxyvitamin D2 [25(OH)D2] and 25-hydroxyvitamin D3 [25(OH)D3]. The two compounds of interest together with spiked deuterium-labeled internal standards [d 3-25(OH)D2 and d 6-25(OH)D3] were extracted from serum via liquid-liquid extraction. The featured isotope-dilution LC-MS/MS method used reversed-phase chromatography and atmospheric pressure chemical ionization in positive ion mode. A pentafluorophenylpropyl-packed UHPLC column together with isocratic elution allowed for complete baseline resolution of 25(OH)D2 and 25(OH)D3 from their structural C-3 isomers within 12 min. We evaluated method trueness, precision, potential interferences, matrix effects, limits of quantitation, and measurement uncertainty. Calibration materials were, or were traceable to, NIST Standard Reference Materials 2972. Within-day and total imprecision (CV) averaged 1.9 and 2.0% for 25(OH)D3, respectively, and 2.4 and 3.5% for 25(OH)D2, respectively. Mean trueness was 100.3% for 25(OH)D3 and 25(OH)D2. The limits of quantitation/limits of detection were 4.61/1.38 nmol/L for 25(OH)D3 and 1.46/0.13 nmol/L for 25(OH)D2. When we compared our RMP results to an established RMP using 40 serum samples, we found a nonsignificant mean bias of 0.2% for total 25(OH)D. This candidate RMP for 25(OH)D metabolites meets predefined method performance specifications (≤5% total CV and ≤1.7% bias) and provides sufficient sample throughput to meet the needs of the Centers for Disease Control and Prevention Vitamin D Standardization Certification Program. Graphical abstract Bias assessment using NIST standard reference materials. Legend CDC mean mass fractions (ng/g) ± U 95 (6

  15. Measurement of methyl tert-butyl ether and tert-butyl alcohol in human blood by purge-and-trap gas chromatography-mass spectrometry using an isotope-dilution method.

    PubMed

    Bonin, M A; Ashley, D L; Cardinali, F L; McCraw, J M; Wooten, J V

    1995-01-01

    We developed an isotope-dilution method for measuring methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) in whole human blood using a purge-and-trap gas chromatographic-mass spectrometric method. The labeled analogues for MTBE and TBA were [2H12]methyl tert-butyl ether and [2H9]-tert-butyl alcohol, respectively. Volatiles were removed from the blood by direct helium purging of the liquid; were trapped on a Tenax trap; and were desorbed, cryofocused, and chromatographed on a DB-624 capillary column that was connected directly to the ion source of a mass spectrometer. Detection was by mass analysis using a double-focusing magnetic-sector mass spectrometer operating in the full-scan mode at the medium mass resolution of 3000. For the isotope-dilution method, the minimum detection limits in blood (5-10 mL) are 0.01 microgram/L for MTBE and 0.06 microgram/L for TBA. The isotope-dilution method proved to be a big improvement in recovery, reproducibility, and sensitivity over our previous analytical method, which used the labeled ketone, [4-2H3]-2-butanone, as the internal standard for both MTBE and TBA. The isotope-dilution method has sufficient sensitivity for monitoring blood levels of MTBE and TBA in populations exposed to oxygenated fuels containing MTBE. PMID:7564298

  16. Measurement of Niacin in a Variety of Food Samples by High Performance Liquid Chromatography-Stable Isotope Dilution Mass Spectrometry (AOAC Annual Meeting, Minneapolis, MN, Sept. 2006)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The availability of deuterium-labeled nicotinic acid makes stable isotope dilution mass spectrometry (SIDMS) coupled with liquid chromatography (LC) an attractive option for the determination of the water-soluble B-vitamin, niacin, in food samples. We have developed a method based on AOAC Peer-Verif...

  17. Comparison of the radioisotope dilution-coated charcoal method and a microbiological method (L. leichmannii) for measuring vitamin B12 in serum

    PubMed Central

    Raven, J. L.; Walker, P. L.; Barkhan, P.

    1966-01-01

    A comparison has been made of the radioisotope dilution-coated charcoal method and a microbiological assay (with L. leichmannii as test organism) for determining the concentration of vitamin B12 in serum. A satisfactory correlation was found between the results of the two methods. Under appropriate conditions the reproducibility of the radioisotope method compared favourably with that of the microbiological method. PMID:5333257

  18. Measurement of Niacin in a Variety of Food Samples by High Performance Liquid Chromatography-Stable Isotope Dilution Mass Spectrometry (Experimental Biology, April, 2007, Washington, D.C.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The availability of deuterium-labeled nicotinic acid makes stable isotope dilution mass spectrometry (SIDMS) coupled with liquid chromatography (LC) an attractive option for the determination of the water-soluble B-vitamin, niacin, in food samples. We have developed a method based on AOAC Peer-Verif...

  19. Where Infinite Spin Particles are Localizable

    NASA Astrophysics Data System (ADS)

    Longo, Roberto; Morinelli, Vincenzo; Rehren, Karl-Henning

    2016-07-01

    Particle states transforming in one of the infinite spin representations of the Poincaré group (as classified by E. Wigner) are consistent with fundamental physical principles, but local fields generating them from the vacuum state cannot exist. While it is known that infinite spin states localized in a spacelike cone are dense in the one-particle space, we show here that the subspace of states localized in any double cone is trivial. This implies that the free field theory associated with infinite spin has no observables localized in bounded regions. In an interacting theory, if the vacuum vector is cyclic for a double cone local algebra, then the theory does not contain infinite spin representations. We also prove that if a Doplicher-Haag-Roberts representation (localized in a double cone) of a local net is covariant under a unitary representation of the Poincaré group containing infinite spin, then it has infinite statistics. These results hold under the natural assumption of the Bisognano-Wichmann property, and we give a counter-example (with continuous particle degeneracy) without this property where the conclusions fail. Our results hold true in any spacetime dimension s + 1 where infinite spin representations exist, namely {s≥ 2}.

  20. Evolution in random fitness landscapes: the infinite sites model

    NASA Astrophysics Data System (ADS)

    Park, Su-Chan; Krug, Joachim

    2008-04-01

    We consider the evolution of an asexually reproducing population in an uncorrelated random fitness landscape in the limit of infinite genome size, which implies that each mutation generates a new fitness value drawn from a probability distribution g(w). This is the finite population version of Kingman's house of cards model (Kingman 1978 J. Appl. Probab. 15 1). In contrast to Kingman's work, the focus here is on unbounded distributions g(w) which lead to an indefinite growth of the population fitness. The model is solved analytically in the limit of infinite population size N \\to \\infty and simulated numerically for finite N. When the genome-wide mutation probability U is small, the long-time behavior of the model reduces to a point process of fixation events, which is referred to as a diluted record process (DRP). The DRP is similar to the standard record process except that a new record candidate (a number that exceeds all previous entries in the sequence) is accepted only with a certain probability that depends on the values of the current record and the candidate. We develop a systematic analytic approximation scheme for the DRP. At finite U the fitness frequency distribution of the population decomposes into a stationary part due to mutations and a traveling wave component due to selection, which is shown to imply a reduction of the mean fitness by a factor of 1-U compared to the U \\to 0 limit.

  1. Application of the Akinfiev-Diamond equation of state to neutral hydroxides of metalloids (B(OH)3, Si(OH)4, As(OH)3) at infinite dilution in water over a wide range of the state parameters, including steam conditions

    NASA Astrophysics Data System (ADS)

    Akinfiev, Nikolay N.; Plyasunov, Andrey V.

    2014-02-01

    for gaseous Si(OH)4 were approximated by a function and used in the treatment of data, see Table 1. The fitting procedure to evaluate the parameters of the Akinfiev-Diamond model also included the values of ΔfGo and S° of Si(OH)4 in ideal gas state at standard state conditions.First, to fit the EoS parameters, the dataset for g2∞ (Si(OH)4(aq)) has been generated using accepted experimental data on quartz solubility in water according to the reaction SiO2(quartz) + 2H2O = Si(OH)4(aq), as g2∞(SiOH(aq)(T,P)=g(quartz)(T,P)+2g(HO)(T,P)-RTlnm, where mSi corresponds to the molality of silica in the solution. Thermodynamic properties of quartz were adopted from SUPCRT database (Johnson et al., 1992), while g(H2O)(T, P) was computed using the Hill (1990) and/or Wagner and Pruß (2002) formulations.The fitting procedure was organized as described below. It is known that partial molar properties of dilute solutes close to the critical point of water are governed by the Krichevskii parameter, AKr (Levelt Sengers, 1991). Plyasunov (2012) recommended for Si(OH)4AKr = -190 ± 10 MPa evaluated from the available relevant data. We have used this value as an anchor while fitting. So, the fitting procedure was iterative. After any initial approximation for ξ, values of the a, b parameters of the EoS together with ΔfGo298(g) and So298(g) of Si(OH)4 were determined by a linear regression of the available g2∞ (Si(OH)4(aq)) experimental data. Then the ξ parameter was modified in compliance with the adopted AKr value (Eq. A7), and the fitting cycle was repeated until ξ ceased changing.The finally retrieved values for gaseous Si(OH)4 are ΔfGo298 = -1239.66 ± 1.7 kJ mol-1, So298 = 346.37 ± 3.5 J mol-1 K-1, and the EoS parameters are ξ = -1.8933; a = 0.9285 ± 1.1 cm3 g-1; b = -0.9409 ± 0.97 cm3 K0.5 g-1 (2σ confidence) (Table 1). Evaluated in this work values of ΔfGo298 and So298 for Si(OH)4 in the ideal gas state are very close to the data given in Plyasunov (2011b) on the

  2. Dilution, Concentration, and Flotation

    ERIC Educational Resources Information Center

    Liang, Ling; Schmuckler, Joseph S.

    2004-01-01

    As both classroom teaching practice and literature show, many students have difficulties learning science concepts such as density. Here are some investigations that identify the relationship between density and floating through experimenting with successive dilution of a liquid, or the systematic change of concentration of a saltwater solution.…

  3. Helium dilution refrigeration system

    DOEpatents

    Roach, P.R.; Gray, K.E.

    1988-09-13

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

  4. Helium dilution refrigeration system

    DOEpatents

    Roach, Patrick R.; Gray, Kenneth E.

    1988-01-01

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

  5. Semi-infinite cohomology and string theory

    PubMed Central

    Frenkel, I. B.; Garland, H.; Zuckerman, G. J.

    1986-01-01

    We develop the theory of semi-infinite cohomology of graded Lie algebras first introduced by Feigin. We show that the relative semi-infinite cohomology has a structure analogous to that of the de Rham cohomology in Kähler geometry. We prove a vanishing theorem for a special class of modules, and we apply our results to the case of the Virasoro algebra and the Fock module. In this case the zero cohomology is identified as the physical subspace of the Fock module and the no-ghost theorem follows. We reveal the profound relation of semi-infinite cohomology theory to the gauge-invariant free string theory constructed by Banks and Peskin. We then indicate the connection between gauge-invariant interacting string theories and the geometric realizations of the infinite-dimensional Lie algebras. PMID:16578792

  6. Semi-infinite cohomology and string theory.

    PubMed

    Frenkel, I B; Garland, H; Zuckerman, G J

    1986-11-01

    We develop the theory of semi-infinite cohomology of graded Lie algebras first introduced by Feigin. We show that the relative semi-infinite cohomology has a structure analogous to that of the de Rham cohomology in Kähler geometry. We prove a vanishing theorem for a special class of modules, and we apply our results to the case of the Virasoro algebra and the Fock module. In this case the zero cohomology is identified as the physical subspace of the Fock module and the no-ghost theorem follows. We reveal the profound relation of semi-infinite cohomology theory to the gauge-invariant free string theory constructed by Banks and Peskin. We then indicate the connection between gauge-invariant interacting string theories and the geometric realizations of the infinite-dimensional Lie algebras. PMID:16578792

  7. Understanding the behaviour of infinite ladder circuits

    NASA Astrophysics Data System (ADS)

    Ucak, C.; Yegin, K.

    2008-11-01

    Infinite ladder circuits are often encountered in undergraduate electrical engineering and physics curricula when dealing with series and parallel combination of impedances, as a part of filter design or wave propagation on transmission lines. The input impedance of such infinite ladder circuits is derived by assuming that the input impedance does not change when a new block of impedance is added. However, the impedance derived from this assumption may lead to incorrect conclusions if it is not treated carefully. Sometimes, in the literature, the input impedance behaviour of infinite ladder circuits is referred to as a paradox, leaving students and educators in doubt. This study intends to clarify this confusion and help to better comprehend the behaviour of the input impedance of infinite ladder circuits.

  8. Maximum independent set on diluted triangular lattices.

    PubMed

    Fay, C W; Liu, J W; Duxbury, P M

    2006-05-01

    Core percolation and maximum independent set on random graphs have recently been characterized using the methods of statistical physics. Here we present a statistical physics study of these problems on bond diluted triangular lattices. Core percolation critical behavior is found to be consistent with the standard percolation values, though there are strong finite size effects. A transfer matrix method is developed and applied to find accurate values of the density and degeneracy of the maximum independent set on lattices of limited width but large length. An extrapolation of these results to the infinite lattice limit yields high precision results, which are tabulated. These results are compared to results found using both vertex based and edge based local probability recursion algorithms, which have proven useful in the analysis of hard computational problems, such as the satisfiability problem. PMID:16803003

  9. Bulk Viscosity and Conformal Symmetry Breaking in the Dilute Fermi Gas near Unitarity

    NASA Astrophysics Data System (ADS)

    Dusling, Kevin; Schäfer, Thomas

    2013-09-01

    The dilute Fermi gas at unitarity is scale invariant and its bulk viscosity vanishes. We compute, in the high temperature limit, the leading contribution to the bulk viscosity when the scattering length is not infinite. A measure of scale breaking is provided by the ratio (P-2/3E)/P, where P is the pressure and E is the energy density. At high temperature this ratio scales as zλ/a, where z is the fugacity, λ is the thermal wavelength, and a is the scattering length. We show that the bulk viscosity ζ scales as the second power of this parameter, ζ˜(zλ/a)2λ-3.

  10. Structure of local quantum operations and classical communication: Finite versus infinite rounds

    NASA Astrophysics Data System (ADS)

    Cohen, Scott M.

    2015-04-01

    Every measurement that can be implemented by local quantum operations and classical communication (LOCC) using an infinite number of rounds is the limit of a sequence of measurements, where each measurement in the sequence requires only a finite number of rounds. This rather obvious and well-known fact is nonetheless of interest as it shows that these infinite-round measurements can be approximated arbitrarily closely simply by using more and more rounds of communication. Here we demonstrate the perhaps less obvious result that (at least) for bipartite systems, the reverse relationship also holds. Specifically, we show that every finite-round bipartite LOCC measurement is the limit of a continuous sequence of LOCC measurements, where each measurement in that sequence can be implemented by LOCC, but only with the use of an infinite number of rounds. Thus, the set of LOCC measurements that require an infinite number of rounds is dense in the entirety of LOCC, as is the set of finite-round LOCC measurements. This means there exist measurements that can only be implemented by LOCC by using an infinite number of rounds, but can nonetheless be approximated closely by using one round of communication, and actually in some cases, no communication is needed at all. These results follow from a necessary condition presented here for finite-round LOCC, which is extremely simple to check, is very easy to prove, and which can be violated by utilizing an infinite number of rounds.

  11. Automatic dilution gaging of rapidly varying flow

    USGS Publications Warehouse

    Duerk, M.D.

    1983-01-01

    The analysis showed that the discharges measured by dye-dilution techniques were generally within ± 10 percent of the discharges determined from ratings established by current-meter measurements. Larger differences were noted at the start of and on the rising limb of four hydrographs. Of the 20 storms monitored, dilution measurements on 17 were of acceptable accuracy. Peak discharges from the open-channel site ranged from 0 to 12 percent departures from the existing rating whereas the comparison of peak discharge at the storm sewer site ranged from 0 to 5 percent departures from the existing rating.

  12. Gluconeogenesis from labeled carbon: estimating isotope dilution

    SciTech Connect

    Kelleher, J.K.

    1986-03-01

    To estimate the rate of gluconeogenesis from steady-state incorporation of labeled 3-carbon precursors into glucose, isotope dilution must be considered so that the rate of labeling of glucose can be quantitatively converted to the rate of gluconeogenesis. An expression for the value of this isotope dilution can be derived using mathematical techniques and a model of the tricarboxylic acid (TCA) cycle. The present investigation employs a more complex model than that used in previous studies. This model includes the following pathways that may affect the correction for isotope dilution: 1) flux of 3-carbon precursor to the oxaloacetate pool via acetyl-CoA and the TCA cycle; 2) flux of 4- or 5-carbon compounds into the TCA cycle; 3) reversible flux between oxaloacetate (OAA) and pyruvate and between OAA and fumarate; 4) incomplete equilibrium between OAA pools; and 5) isotope dilution of 3-carbon tracers between the experimentally measured pool and the precursor for the TCA-cycle OAA pool. Experimental tests are outlined which investigators can use to determine whether these pathways are significant in a specific steady-state system. The study indicated that flux through these five pathways can significantly affect the correction for isotope dilution. To correct for the effects of these pathways an alternative method for calculating isotope dilution is proposed using citrate to relate the specific activities of acetyl-CoA and OAA.

  13. Minimal Coital Dilution in Accra, Ghana

    PubMed Central

    Jenness, Samuel M.; Biney, Adriana A. E.; Ampofo, William Kwabena; Dodoo, F. Nii-Amoo; Cassels, Susan

    2015-01-01

    Background Coital dilution, the reduction in the coital frequency per partner when an additional ongoing partner is added, may reduce the transmission potential of partnership concurrency for HIV and other sexually transmitted infections. Empirical estimates of dilution, especially dilution of sexual acts unprotected by condoms, are needed to inform prevention research. Methods Sexually active adults in Accra, Ghana were recruited in a multi-stage household probability sample. Degree (number of ongoing partners), total acts, and unprotected acts were measured retrospectively for each month in the past year through an event-history calendar. Random effects negative binomial models estimated the association between degree and coital frequency. Results Compared to person-months with a single partner (monogamy), 2.06 times as many total acts and 1.94 times as many unprotected acts occurred in months with 2 partners. In months with 3 partners, 2.90 times as many total acts and 2.39 times as many unprotected acts occurred compared to monogamous months. Total acts but not unprotected acts also declined with partnership duration. Conclusions No dilution was observed for total acts with up to three concurrent partners, but a small amount of dilution was observed for unprotected acts for months with multiple concurrencies. This suggests moderate selective condom use in months with multiple concurrencies. The implications of the observed dilution for future HIV transmission must be investigated with mathematical models. PMID:25622062

  14. The solvent dependence of ionic properties in solution in the limit of infinite dilution

    NASA Astrophysics Data System (ADS)

    Fawcett, W. Ronald

    1998-10-01

    The dependence of the Gibbs solvation energy and limiting ionic conductance for simple ions on the solvent nature is discussed for a collection of data in 18 polar solvents both protic and aprotic. It is shown that the Gibbs solvation energy depends on the acidity and basicity of the solvent, concepts based on a detailed quantum mechanical description of the solvent molecule and its interaction with ions in its vicinity. On the other hand, ionic mobility, after correction for solvent viscosity, depends on the size of the surrounding molecules, and to a lesser extent on their acid-base properties.

  15. Inoculation of Bacillus sphaericus UPMB-10 to Young Oil Palm and Measurement of Its Uptake of Fixed Nitrogen Using the 15N Isotope Dilution Technique

    PubMed Central

    Zakry, Fitri Abdul Aziz; Shamsuddin, Zulkifli H.; Rahim, Khairuddin Abdul; Zakaria, Zin Zawawi; Rahim, Anuar Abdul

    2012-01-01

    There are increasing applications of diazotrophic rhizobacteria in the sustainable agriculture system. A field experiment on young immature oil palm was conducted to quantify the uptake of N derived from N2 fixation by the diazotroph Bacillus sphaericus strain UPMB-10, using the 15N isotope dilution method. Eight months after 15N application, young immature oil palms that received 67% of standard N fertilizer application together with B. sphaericus inoculation had significantly lower 15N enrichment than uninoculated palms that received similar N fertilizers. The dilution of labeled N served as a marker for the occurrence of biological N2 fixation. The proportion of N uptake that was derived from the atmosphere was estimated as 63% on the whole plant basis. The inoculation process increased the N and dry matter yields of the palm leaflets and rachis significantly. Field planting of young, immature oil palm in soil inoculated with B. sphaericus UPMB-10 might mitigate inorganic fertilizer-N application through supplementation by biological nitrogen fixation. This could be a new and important source of nitrogen biofertilizer in the early phase of oil palm cultivation in the field. PMID:22446306

  16. Reversible magnetization measurements of the anisotropic superconducting parameters of the infinite-layer electron-doped compound Sr 0.90La 0.10CuO 2 apparent anisotropy crossover

    NASA Astrophysics Data System (ADS)

    Cobb, J. L.; Markert, J. T.

    1994-06-01

    We report the results and analysis of DC magnetization studies of grain-aligned powders of the infinite-layer electron-doped compounds Sr 0.90La 0.10CuO 2. Magnetization data in the reversible temperature regime were analyzed to obtain the anisotropic superconducting parameters for this system. Three samples of Sr 0.90La 0.10CuO 2 were studied, presumably with very slightly diffrent La or O concentrations. Typically, the extracted values of the coherence lengths (ξ ∥=46 Å, ξ ⊥=30 Å), the penetration depths (λ ∥=290 nm, λ ⊥=450 nm), the mass anisotrophy ( ( {m ⊥}/{m ∥}) {1}/{2}≈1.5 ), and the lower and upper critical fields are appreciably less anisotropic than reported values for the electron-doped T‧ phase materials, possibly because the infinite-layer compound has a significantly shorter interplanar spacing (3.4 Å versus 6.0 Å). One notable sample, moreover, exhibits an inverse anisotropy (( ( {m ⊥}/{m ∥}) {1}/{2}≈0.6 ), further suggesting that this system behaves much like a three-dimensional metal.

  17. Seismic stability of gentle infinite slopes

    SciTech Connect

    Hadj-Hamou, T.; Kavazanjian, E.

    1985-06-01

    Deterministic and probabilistic analyses of the stability of gentle infinite slopes subject to seismically induced excess pore pressures and inertia forces are developed. In the deterministic analysis, classical equations for infinite slope stability are rewritten to explicitly include excess pore pressure and seismic acceleration. Equations for the factor of safety are developed that include these factors. In the probabilistic analysis, the seismic acceleration, excess pore pressure, and effective friction angle are considered random variables. Acceleration peaks are considered Rayleigh distributed. Excess pore pressure is predicted using a model that considers Rayleigh distributed shear stress peaks. The friction angle is modeled with a Beta distribution. Acceleration and pore pressure development within the gentle infinite slope are assumed the same as those in a horizontal deposit of the same average thicknesss. Finite element analyses are performed to investigate the limits of this assumption. Results from both analyses are compared to documented case histories of lateral spreading.

  18. Automatic diluter for bacteriological samples.

    PubMed

    Trinel, P A; Bleuze, P; Leroy, G; Moschetto, Y; Leclerc, H

    1983-02-01

    The described apparatus, carrying 190 tubes, allows automatic and aseptic dilution of liquid or suspended-solid samples. Serial 10-fold dilutions are programmable from 10(-1) to 10(-9) and are carried out in glass tubes with screw caps and split silicone septa. Dilution assays performed with strains of Escherichia coli and Bacillus stearothermophilus permitted efficient conditions for sterilization of the needle to be defined and showed that the automatic dilutions were as accurate and as reproducible as the most rigorous conventional dilutions. PMID:6338826

  19. Automatic diluter for bacteriological samples.

    PubMed Central

    Trinel, P A; Bleuze, P; Leroy, G; Moschetto, Y; Leclerc, H

    1983-01-01

    The described apparatus, carrying 190 tubes, allows automatic and aseptic dilution of liquid or suspended-solid samples. Serial 10-fold dilutions are programmable from 10(-1) to 10(-9) and are carried out in glass tubes with screw caps and split silicone septa. Dilution assays performed with strains of Escherichia coli and Bacillus stearothermophilus permitted efficient conditions for sterilization of the needle to be defined and showed that the automatic dilutions were as accurate and as reproducible as the most rigorous conventional dilutions. Images PMID:6338826

  20. Theory and experiment for infinite microstrip arrays

    NASA Astrophysics Data System (ADS)

    Wright, S. M.; Lo, Y. T.

    1985-01-01

    Microstrip antennas are well suited for use in large scanning arrays. To obtain greater bandwidth, it is useful to use thicker substrates, which can increase the effects of mutual coupling and lead to significant mismatch or blindness for certain scan angles. Using an infinite array formulation, the impedance of a single element in an infinite array environment was solved with the method of moments. Mutual coupling is built into the solution, and the presence of surface waves is accounted for by using the periodic Green's function for the grounded dielectric substrate. Blindness in arrays of microstrip dipoles on various substrates, both with and without radomes is demonstrated.

  1. The Infinite in the Finite

    NASA Astrophysics Data System (ADS)

    Macintosh Wilson, Alistair

    1996-01-01

    A conversation between Euclid and the ghost of Socrates. . . the paths of the moon and the sun charted by the stone-builders of ancient Europe. . .the Greek ideal of the golden mean by which they measured beauty. . . Combining historical fact with a retelling of ancient myths and legends, this lively and engaging book describes the historical, religious and geographical background that gave rise to mathematics in ancient Egypt, Babylon, China, Greece, India, and the Arab world. Each chapter contains a case study where mathematics is applied to the problems of the era, including the area of triangles and volume of the Egyptian pyramids; the Babylonian sexagesimal number system and our present measure of space and time which grew out of it; the use of the abacus and remainder theory in China; the invention of trigonometry by Arab mathematicians; and the solution of quadratic equations by completing the square developed in India. These insightful commentaries will give mathematicians and general historians a better understanding of why and how mathematics arose from the problems of everyday life, while the author's easy, accessible writing style will open fascinating chapters in the history of mathematics to a wide audience of general readers.

  2. Ebulliometers for measuring the thermodynamic properties of fluids and fluid mixtures

    SciTech Connect

    Weber, L.A.; Silva, A.M.

    1994-09-01

    The design and operation of two ebulliometers is described. One is constructed of glass and is used for measuring vapor pressures of fluids at low reduced temperatures and pressures. The other is constructed of metal. It can be used for vapor pressure measurements, and also for the study of fluid mixture thermodynamics through the determination of the activity coefficients at infinite dilution. The advantages and potential problems associated with ebulliometers are described, and typical results are given for the properties of alternative refrigerants.

  3. Efficient analysis for infinite microstrip dipole arrays

    NASA Astrophysics Data System (ADS)

    Wright, S. M.; Lo, Y. T.

    1983-11-01

    A moment method analysis of infinite microstrip dipole arrays which uses an efficient technique to evaluate the generalized impedance matrix is described. A particularly simple formulation is obtained through the use of the periodic Green function. Results for the reflection coefficient magnitude against scan angle are given for a typical array.

  4. Stress on Second Conjugation Infinitives in Italian.

    ERIC Educational Resources Information Center

    Davis, Stuart; And Others

    1987-01-01

    Reviews the limited amount of research regarding ways in which primary stress is assigned to second conjugation infinitives in Italian and then proposes a new perspective taking into consideration root vowels, root-final consonants, syllable onset, monosyllabic vs. polysyllabic roots, and canonical form. (CB)

  5. Infinite Sums of M-Bonacci Numbers

    ERIC Educational Resources Information Center

    A-iru, Muniru A.

    2009-01-01

    In this note, we construct infinite series using M-bonacci numbers in a manner similar to that used in previous studies and investigate the convergence of the series to an integer. Our results generalize the ones obtained for Fibonacci numbers.

  6. On infinite-dimensional state spaces

    SciTech Connect

    Fritz, Tobias

    2013-05-15

    It is well known that the canonical commutation relation [x, p]=i can be realized only on an infinite-dimensional Hilbert space. While any finite set of experimental data can also be explained in terms of a finite-dimensional Hilbert space by approximating the commutation relation, Occam's razor prefers the infinite-dimensional model in which [x, p]=i holds on the nose. This reasoning one will necessarily have to make in any approach which tries to detect the infinite-dimensionality. One drawback of using the canonical commutation relation for this purpose is that it has unclear operational meaning. Here, we identify an operationally well-defined context from which an analogous conclusion can be drawn: if two unitary transformations U, V on a quantum system satisfy the relation V{sup -1}U{sup 2}V=U{sup 3}, then finite-dimensionality entails the relation UV{sup -1}UV=V{sup -1}UVU; this implication strongly fails in some infinite-dimensional realizations. This is a result from combinatorial group theory for which we give a new proof. This proof adapts to the consideration of cases where the assumed relation V{sup -1}U{sup 2}V=U{sup 3} holds only up to {epsilon} and then yields a lower bound on the dimension.

  7. On infinite-dimensional state spaces

    NASA Astrophysics Data System (ADS)

    Fritz, Tobias

    2013-05-01

    It is well known that the canonical commutation relation [x, p] = i can be realized only on an infinite-dimensional Hilbert space. While any finite set of experimental data can also be explained in terms of a finite-dimensional Hilbert space by approximating the commutation relation, Occam's razor prefers the infinite-dimensional model in which [x, p] = i holds on the nose. This reasoning one will necessarily have to make in any approach which tries to detect the infinite-dimensionality. One drawback of using the canonical commutation relation for this purpose is that it has unclear operational meaning. Here, we identify an operationally well-defined context from which an analogous conclusion can be drawn: if two unitary transformations U, V on a quantum system satisfy the relation V-1U2V = U3, then finite-dimensionality entails the relation UV-1UV = V-1UVU; this implication strongly fails in some infinite-dimensional realizations. This is a result from combinatorial group theory for which we give a new proof. This proof adapts to the consideration of cases where the assumed relation V-1U2V = U3 holds only up to ɛ and then yields a lower bound on the dimension.

  8. A Planar Calculus for Infinite Index Subfactors

    NASA Astrophysics Data System (ADS)

    Penneys, David

    2013-05-01

    We develop an analog of Jones' planar calculus for II 1-factor bimodules with arbitrary left and right von Neumann dimension. We generalize to bimodules Burns' results on rotations and extremality for infinite index subfactors. These results are obtained without Jones' basic construction and the resulting Jones projections.

  9. Two-dimensional heart-cut LC-LC improves accuracy of exact-matching double isotope dilution mass spectrometry measurements of aflatoxin B1 in cereal-based baby food, maize, and maize-based feed.

    PubMed

    Breidbach, Andreas; Ulberth, Franz

    2015-04-01

    Aflatoxins, mycotoxins of fungi of the Aspergillus sp., pose a risk to consumer health and are, therefore, regulated by more than 100 countries. To facilitate method development and validation as well as assessment of measurement capabilities, availability of certified reference materials and proficiency testing schemes is important. For these purposes, highly accurate determinations of the aflatoxin content in the materials used are necessary. We describe here the use of two-dimensional heart-cut LC-LC in combination with exact-matching double isotope dilution mass spectrometry to determine the content of aflatoxin B1 in three materials used in a proficiency testing scheme. The serious reduction in ionization suppression afforded by the two-dimensional heart-cut LC-LC had a positive effect on the precision of the measured isotope ratios of the exact-matching double isotope dilution mass spectrometry. This is evidenced by the expanded measurement uncertainty (k=2) of 0.017 μg/kg or 8.9 % relative to a mass fraction of aflatoxin B1 in a cereal-based baby food of 0.197 μg/kg. This value is in perfect agreement with the consensus value of this material from a proficiency test (PT) scheme for National Reference Laboratories executed by the European Reference Laboratory for Mycotoxins. The effort necessary to perform the described methodology precludes its frequent use but for specific applications we see it as a valuable tool. PMID:25015044

  10. Limiting equilibrium and liquefaction potential in infinite submarine slopes

    USGS Publications Warehouse

    Denlinger, R.P.; Iverson, R.M.

    1990-01-01

    Stability evaluation of submarine slopes is hampered by the difficulty of making field measurements. Owing to the scarcity of detailed field data, stability is commonly assessed by assuming homogenous infinite slopes with steady seepage. For these conditions, it is necessary to measure only the slope angle, friction angle, cohesion, and pore pressure at some distance into the sediment to evaluate stability. Examination of available data shows that conditions close to those required for liquefaction are necessary for Coulomb failure in many continental shelf areas. This favors long landslide runouts and flow of sediment subsequent to failure. -from Authors

  11. Semi-Infinite Cohomology of Loop Spaces

    NASA Astrophysics Data System (ADS)

    Shutler, Paul Maurice Edmund

    Available from UMI in association with The British Library. Requires signed TDF. This thesis attempts to construct a de Rham model for the Floer homology of the space of free loops on a symplectic manifold. It derives its inspiration principally from the work of Witten on topological quantum field theories. Chapter 1 consist of a review of background material followed by a number of elementary results. It is seen how Floer homology should naturally be representable by a semi-infinite generalisation of the ordinary de Rham theory associated to a manifold. In Chapter 2 the main attempt at constructing such a semi-infinite theory is made by defining an exterior derivative. Two different kinds of divergences are encountered and resolved. A suitable space of semi-infinite forms is constructed and some remarks are made about the likelihood that this model captures the Floer homology. In Chapter 3 the obstruction to the existence of a chiral factorisation of the bundle of fermionic Fock spaces over the loop space of the two-sphere is computed. For this purpose the ordinary cohomology ring of the loop space is calculated, also the action of the deck transformation on the cohomology of the simply connected covering space. In Chapter 4 the supersymmetric path integral approach to quantising topological field theories is developed formally. The semi-infinite dimensionality of the differential forms involved emerges naturally. The Floer homology of loop space is shown to be a ring. Its structure is calculated for the simple case of complex projective space. Chapter 5 concludes the thesis with some remarks about the action of the super-Virasoro algebra on the space of ordinary and semi-infinite differential forms respectively. Two short appendices are included describing a polynomial generating function for spherical harmonics and the spectrum of curl on vector fields on the three -sphere.

  12. Sulfuric Acid and Water: Paradoxes of Dilution

    ERIC Educational Resources Information Center

    Leenson, I. A.

    2004-01-01

    On equilibrium properties of aqueous solutions of sulfuric acid, Julius Thomsen has marked that the heat evolved on diluting liquid sulfuric acid with water is a continuous function of the water used, and excluded absolutely the acceptance of definite hydrates as existing in the solution. Information about thermochemical measurement, a discussion…

  13. Dilution jet mixing program

    NASA Technical Reports Server (NTRS)

    Srinivasan, R.; Coleman, E.; Johnson, K.

    1984-01-01

    Parametric tests were conducted to quantify the mixing of opposed rows of jets (two-sided injection) in a confined cross flow. Results show that jet penetrations for two sided injections are less than that for single-sided injections, but the jet spreading rates are faster for a given momentum ratio and orifice plate. Flow area convergence generally enhances mixing. Mixing characteristics with asymmetric and symmetric convergence are similar. For constant momentum ratio, the optimum S/H(0) with in-line injections is one half the optimum value for single sided injections. For staggered injections, the optimum S/H(0) is twice the optimum value for single-sided injection. The correlations developed predicted the temperature distributions within first order accuracy and provide a useful tool for predicting jet trajectory and temperature profiles in the dilution zone with two-sided injections.

  14. Scaling of Greenwood Peierls conductance on a diluted square lattice

    NASA Astrophysics Data System (ADS)

    Schwalm, William; Schmitz, Albert

    The modified rectangle lattice of Dhar is a bond-diluted square lattice. The structure is self-similar and finitely ramified, like a fractal. Nevertheless certain discrete Schrödinger equation Green functions for the modified rectangle are known in closed form in the infinite lattice limit and the spectrum is continuous. By standard transfer matrix renormalization methods we present a study scaling properties of the Greenwood Peierls conductance distribution across the lattice with one dimensional lead wires attached as a function of lattice size and of additional disorder of several types.

  15. Standard dilution analysis.

    PubMed

    Jones, Willis B; Donati, George L; Calloway, Clifton P; Jones, Bradley T

    2015-02-17

    Standard dilution analysis (SDA) is a novel calibration method that may be applied to most instrumental techniques that will accept liquid samples and are capable of monitoring two wavelengths simultaneously. It combines the traditional methods of standard additions and internal standards. Therefore, it simultaneously corrects for matrix effects and for fluctuations due to changes in sample size, orientation, or instrumental parameters. SDA requires only 200 s per sample with inductively coupled plasma optical emission spectrometry (ICP OES). Neither the preparation of a series of standard solutions nor the construction of a universal calibration graph is required. The analysis is performed by combining two solutions in a single container: the first containing 50% sample and 50% standard mixture; the second containing 50% sample and 50% solvent. Data are collected in real time as the first solution is diluted by the second one. The results are used to prepare a plot of the analyte-to-internal standard signal ratio on the y-axis versus the inverse of the internal standard concentration on the x-axis. The analyte concentration in the sample is determined from the ratio of the slope and intercept of that plot. The method has been applied to the determination of FD&C dye Blue No. 1 in mouthwash by molecular absorption spectrometry and to the determination of eight metals in mouthwash, wine, cola, nitric acid, and water by ICP OES. Both the accuracy and precision for SDA are better than those observed for the external calibration, standard additions, and internal standard methods using ICP OES. PMID:25599250

  16. History of the Infinitely Small and the Infinitely Large in Calculus.

    ERIC Educational Resources Information Center

    Kleiner, Israel

    2001-01-01

    Considers examples of aspects of the infinitely small and large as they unfolded in the history of calculus from the 17th through the 20th centuries. Presents didactic observations at relevant places in the historical account. (Author/MM)

  17. Measurement of 2-carboxyarabinitol 1-phosphate in plant leaves by isotope dilution. [Spinacea oleracea; Triticum aestivum; Arabidopsis thaliana; Maize; Phaseolus vulgaris; Petunia hybrida

    SciTech Connect

    Moore, B.D.; Kobza, J.; Seemann, J.R. )

    1991-05-01

    The level of 2-carboxyarabinitol 1-phosphate (CA1P) in leaves of 12 species was determined by an isotope dilution assay. {sup 14}C-labeled standard was synthesized from (2-{sup 14}C)carboxyarabinitol 1,5-bisphosphate using acid phosphatase, and was added at the initial point of leaf extraction. Leaf CA1P was purified and its specific activity determined. CA1P was found in dark-treated leaves of all species examined, including spinach (Spinacea oleracea), wheat (Triticum aestivum), Arabidopsis thaliana, and maize (Zea mays). The highest amounts were found in bean (Phaseolus vulgaris) and petunia (Petunia hybrida), which had 1.5 to 1.8 moles CA1P per mole ribulose 1,5-bisphosphate carboxylase catalytic sites. Most species had intermediate amounts of CA1P (0.2 to 0.8 mole CA1P per mole catalytic sites). Such intermediate to high levels of CA1P support the hypothesis that CA1P functions in many species as a light-dependent regulator of ribulose 1,5-bisphosphate carboxylase activity and whole leaf photosynthetic CO{sub 2} assimilation. However, CA1P levels in spinach, wheat, and A. thaliana were particularly low (less than 0.09 mole CA1P per mole catalytic sites). In such species, CA1P does not likely have a significant role in regulating ribulose 1,5-bisphosphate carboxylase activity, but could have a different physiological role.

  18. Elevated urinary levels of carcinogenic N-nitrosamines in patients with urinary tract infections measured by isotope dilution online SPE LC-MS/MS.

    PubMed

    Hu, Chiung-Wen; Shih, Ying-Ming; Liu, Hung-Hsin; Chiang, Yi-Chen; Chen, Chih-Ming; Chao, Mu-Rong

    2016-06-01

    N-nitrosamines (NAms) are well-documented for their carcinogenic potential. Human exposure to NAms may arise from the daily environment and endogenous formation via the reaction of secondary amines with nitrites or from bacteria infection. We describe the use of isotope dilution online solid-phase extraction (SPE) LC-MS/MS to quantify nine NAms in human urine. This method was validated and further applied to healthy subjects and patients with urinary tract infection (UTI). N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR) and N-nitrosomorpholine (NMOR) were analyzed with an APCI source, while N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosodi-n-propylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA) were quantified with an ESI source, due to their effect on the sensitivity and chromatography. NDMA was the most abundant N-nitrosamine, while NDPhA was firstly identified in human. UTI patients had three to twelve-fold higher concentrations for NDMA, NPIP, NDEA, NMOR and NDBA in urine than healthy subjects, and the NAms were significantly decreased after antibiotics treatment. NDMA concentrations were also significantly correlated with the pH value, leukocyte esterase activity or nitrite in urines of UTI patients. Our findings by online SPE LC-MS/MS method evidenced that UTI patients experienced various NAms exposures, especially the potent carcinogen NDMA, which was likely induced by bacteria infection. PMID:26937867

  19. Ultra-trace level speciated isotope dilution measurement of Cr(VI) using ion chromatography tandem mass spectrometry in environmental waters.

    PubMed

    Mädler, Stefanie; Todd, Aaron; Skip Kingston, H M; Pamuku, Matt; Sun, Fengrong; Tat, Cindy; Tooley, Robert J; Switzer, Teresa A; Furdui, Vasile I

    2016-08-15

    The reliable analysis of highly toxic hexavalent chromium, Cr(VI), at ultra-trace levels remains challenging, given its easy conversion to non-toxic trivalent chromium. This work demonstrates a novel analytical method to quantify Cr(VI) at low ngL(-1) concentration levels in environmental water samples by using speciated isotope dilution (SID) analysis and double-spiking with Cr(III) and Cr(VI) enriched for different isotopes. Ion chromatography tandem mass spectrometry (IC-MS/MS) was used for the analysis of Cr(VI) as HCrO4(-) → CrO3(-). Whereas the classical linear multipoint calibration (MPC) curve approach obtained a method detection limit (MDL) of 7ngL(-1) Cr(VI), the modified SID-MS method adapted from U. S. EPA 6800 allowed for the quantification of Cr(VI) with an MDL of 2ngL(-1) and provided results corrected for Cr(VI) loss occurred after sample collection. The adapted SID-MS approach proved to yield more accurate and precise results than the MPC method, allowed for compensation of Cr(VI) reduction during sample transportation and storage while eliminating the need for frequent external calibration. The developed method is a complementary tool to routinely used inductively-coupled plasma (ICP) MS and circumvents typically experienced interferences. PMID:27260441

  20. Entanglement convertibility for infinite-dimensional pure bipartite states

    SciTech Connect

    Owari, Masaki; Matsumoto, Keiji; Murao, Mio

    2004-11-01

    It is shown that the order property of pure bipartite states under stochastic local operations and classical communications (SLOCC) changes radically when dimensionality shifts from finite to infinite. In contrast to finite-dimensional systems where there is no pure incomparable state, the existence of infinitely many mutually SLOCC incomparable states is shown for infinite-dimensional systems even under the bounded energy and finite information exchange condition. These results show that the effect of the infinite dimensionality of Hilbert space, the 'infinite workspace' property, remains even in physically relevant infinite-dimensional systems.

  1. 40 CFR 1066.610 - Dilution air background correction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Calculations § 1066.610 Dilution air background correction. (a... ratio of the test fuel. You may measure a or use default values from Table 1 of 40 CFR 1065.655. b... 40 CFR 1065.655. ER28AP14.101 (c) Determine the dilution factor, DF, over the test interval...

  2. A Stochastic Tikhonov Theorem in Infinite Dimensions

    SciTech Connect

    Buckdahn, Rainer Guatteri, Giuseppina

    2006-03-15

    The present paper studies the problem of singular perturbation in the infinite-dimensional framework and gives a Hilbert-space-valued stochastic version of the Tikhonov theorem. We consider a nonlinear system of Hilbert-space-valued equations for a 'slow' and a 'fast' variable; the system is strongly coupled and driven by linear unbounded operators generating a C{sub 0}-semigroup and independent cylindrical Brownian motions. Under well-established assumptions to guarantee the existence and uniqueness of mild solutions, we deduce the required stability of the system from a dissipativity condition on the drift of the fast variable. We avoid differentiability assumptions on the coefficients which would be unnatural in the infinite-dimensional framework.

  3. Quark ensembles with the infinite correlation length

    SciTech Connect

    Zinov’ev, G. M.; Molodtsov, S. V.

    2015-01-15

    A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble.

  4. Infinitely many singular interactions on noncompact manifolds

    SciTech Connect

    Kaynak, Burak Tevfik Turgut, O. Teoman

    2015-05-15

    We show that the ground state energy is bounded from below when there are infinitely many attractive delta function potentials placed in arbitrary locations, while all being separated at least by a minimum distance, on two dimensional non-compact manifold. To facilitate the reading of the paper, we first present the arguments in the setting of Cartan–Hadamard manifolds and then subsequently discuss the general case. For this purpose, we employ the heat kernel techniques as well as some comparison theorems of Riemannian geometry, thus generalizing the arguments in the flat case following the approach presented in Albeverio et al. (2004). - Highlights: • Schrödinger-operator for infinitely many singular interactions on noncompact manifolds. • Proof of the finiteness of the ground-state energy.

  5. Variational Infinite Hidden Conditional Random Fields.

    PubMed

    Bousmalis, Konstantinos; Zafeiriou, Stefanos; Morency, Louis-Philippe; Pantic, Maja; Ghahramani, Zoubin

    2015-09-01

    Hidden conditional random fields (HCRFs) are discriminative latent variable models which have been shown to successfully learn the hidden structure of a given classification problem. An Infinite hidden conditional random field is a hidden conditional random field with a countably infinite number of hidden states, which rids us not only of the necessity to specify a priori a fixed number of hidden states available but also of the problem of overfitting. Markov chain Monte Carlo (MCMC) sampling algorithms are often employed for inference in such models. However, convergence of such algorithms is rather difficult to verify, and as the complexity of the task at hand increases the computational cost of such algorithms often becomes prohibitive. These limitations can be overcome by variational techniques. In this paper, we present a generalized framework for infinite HCRF models, and a novel variational inference approach on a model based on coupled Dirichlet Process Mixtures, the HCRF-DPM. We show that the variational HCRF-DPM is able to converge to a correct number of represented hidden states, and performs as well as the best parametric HCRFs-chosen via cross-validation-for the difficult tasks of recognizing instances of agreement, disagreement, and pain in audiovisual sequences. PMID:26353136

  6. Scan blindness in infinite phased arrays of printed dipoles

    NASA Technical Reports Server (NTRS)

    Pozar, D. M.; Schaubert, D. H.

    1984-01-01

    A comprehensive study of infinite phased arrays of printed dipole antennas is presented, with emphasis on the scan blindness phenomenon. A rigorous and efficient moment method procedure is used to calculate the array impedance versus scan angle. Data are presented for the input reflection coefficient for various element spacings and substrate parameters. A simple theory, based on coupling from Floquet modes to surface wave modes on the substrate, is shown to predict the occurrence of scan blindness. Measurements from a waveguide simulator of a blindness condition confirm the theory.

  7. Stress in dilute suspensions

    NASA Technical Reports Server (NTRS)

    Passman, Stephen L.

    1989-01-01

    Generally, two types of theory are used to describe the field equations for suspensions. The so-called postulated equations are based on the kinetic theory of mixtures, which logically should give reasonable equations for solutions. The basis for the use of such theory for suspensions is tenuous, though it at least gives a logical path for mathematical arguments. It has the disadvantage that it leads to a system of equations which is underdetermined, in a sense that can be made precise. On the other hand, the so-called averaging theory starts with a determined system, but the very process of averaging renders the resulting system underdetermined. A third type of theory is proposed in which the kinetic theory of gases is used to motivate continuum equations for the suspended particles. This entails an interpretation of the stress in the particles that is different from the usual one. Classical theory is used to describe the motion of the suspending medium. The result is a determined system for a dilute suspension. Extension of the theory to more concentrated systems is discussed.

  8. Solvation Phenomena in Dilute Solutions: Formal, Experimental Evidence, and Modeling Implications

    SciTech Connect

    Chialvo, Ariel A

    2013-01-01

    We review the fundamentals underlying a general molecular-based formalism for the microscopic interpretation of the solvation phenomena involving sparingly soluble solutes in compressible media, an approach that hinges around the unambiguous splitting of the species correlation function integrals into short-(finite) and long-ranged (diverging) contributions at infinite dilution, where this condition is taken as the reference system for the derivation of composition expansions. Then, we invoke the formalism (a) to illustrate the well-behaved nature of the solvation contributions to the mechanical partial molecular properties of solutes at infinite dilution, (b) to guide the development of, and provide molecular-based support to, the macroscopic modeling of high-temperature dilute aqueous-electrolyte solutions, (c) to study solvation effects on the kinetic rate constants of reactions in near-critical solvents in an attempt to understand from a microscopic perspective the macroscopic evidence regarding the thermodynamic pressure effects, and (d) to interpret the microscopic mechanism behind synergistic solvation effects involving either co-solutes or co-solvents, and provide a molecular argument on the unsuitability of the van der Waals one-fluid (vdW-1f) mixing rules for the 2 description of weakly attractive solutes in compressible solvents. Finally, we develop thermodynamically consistent perturbation expansions, around the infinite dilution reference, for the species residual properties in binary and ternary mixtures, and discuss the theoretical and modeling implications behind ad hoc first-order truncated expansions.

  9. On the principal and strictly particular solutions to infinite systems

    NASA Astrophysics Data System (ADS)

    Ivanova, O. F.; Pavlov, N. N.; Fedorov, F. M.

    2016-03-01

    The concepts of the principal solution to infinite systems of linear algebraic equations and the reduction method are defined more precisely. The principal solution, if it exists, is a strictly particular solution to the infinite system. If the reduction method is convergent, then it necessarily converges to Kramer's determinant; however, Kramer's determinant is not always a solution to the infinite system. To confirm the obtained results, analytical and numerical solutions of specific infinite system are considered.

  10. Simultaneous Measurement of 3-Chlorotyrosine and 3,5-Dichlorotyrosine in Whole Blood, Serum and Plasma by Isotope Dilution HPLC-MS-MS.

    PubMed

    Crow, Brian S; Quiñones-González, Jennifer; Pantazides, Brooke G; Perez, Jonas W; Winkeljohn, W Rucks; Garton, Joshua W; Thomas, Jerry D; Blake, Thomas A; Johnson, Rudolph C

    2016-05-01

    Chlorine is a public health concern and potential threat due to its high reactivity, ease and scale of production, widespread industrial use, bulk transportation, massive stockpiles and history as a chemical weapon. This work describes a new, sensitive and rapid stable isotope dilution method for the retrospective detection and quantitation of two chlorine adducts. The biomarkers 3-chlorotyrosine (Cl-Tyr) and 3,5-dichlorotyrosine (Cl2-Tyr) were isolated from the pronase digest of chlorine exposed whole blood, serum or plasma by solid-phase extraction (SPE), separated by reversed-phase HPLC and detected by tandem mass spectrometry (MS-MS). The calibration range is 2.50-1,000 ng/mL (R(2)≥ 0.998) with a lowest reportable limit (LRL) of 2.50 ng/mL for both analytes, an accuracy of ≥93% and an LOD of 0.443 ng/mL for Cl-Tyr and 0.396 ng/mL for Cl2-Tyr. Inter- and intra-day precision of quality control samples had coefficients of variation of ≤10% and ≤7.0%, respectively. Blood and serum samples from 200 healthy individuals and 175 individuals with chronic inflammatory disease were analyzed using this method to assess background levels of chlorinated tyrosine adducts. Results from patients with no known inflammatory disease history (healthy) showed baseline levels of

  11. The Bursting of the Dam (Infinite Sets, Countable and Otherwise).

    ERIC Educational Resources Information Center

    Francis, Richard L.

    1992-01-01

    Examines infinite sets and cardinality classifications of empty, finite but not empty, and infinite through discussions of numbers that fall into particular categories. Categories discussed include perfect numbers, Mersenne primes, pseudoprimes, and transcendental numbers. Discusses the Null Or Infinite Set Effect (NOISE) and infinitude resulting…

  12. Effects of dilution on vehicle emissions of primary particles

    NASA Astrophysics Data System (ADS)

    Hayden, K. L.; Li, S.; Liggio, G.; McCurdy, M.; Chan, T.; Rostkowski, J.

    2009-12-01

    Dilution of primary aerosols from vehicles into the ambient atmosphere can change their physical and chemical characteristics. In order to study these processes, experiments were conducted in an engine testing facility at Environment Canada in Ottawa, Ontario. Exhaust from a light duty diesel engine was vented into a constant volume sampling (CVS) system where it underwent primary dilution at an ambient temperature of 25oC, leading to a primary dilution ratio of 10-15. From the CVS, the exhaust was further diluted using a combination of a Dekati ejection diluter and mixing with zero air in a flow tube, achieving secondary dilution ratios of up to 3000. Particle and gas measurements were made through multi-ports in the CVS and the flow tube using an SMPS, FMPS, AMS, and SP2, and instruments to measure CO, CO2, NOx, and total hydrocarbons (THC). Preliminary results indicate that regardless of dilution ratios, primary particles contain significant amounts of organic material that appear to reside on small black carbon cores. With increasing dilution ratios, the primary particle sizes become progressively smaller, suggesting volatilization of the adsorbed organic material. Results from various engine operating modes (simulating different driving conditions) will be presented.

  13. Dry Dilution Refrigerator with High Cooling Power

    NASA Astrophysics Data System (ADS)

    Uhlig, K.

    2008-03-01

    We present the construction concept and cooling capacity measurements of a 3,4He dilution refrigerator (DR), which was pre-cooled by a commercial pulse tube refrigerator (PTR). No cryogens are needed for the operation of this type of cryostat. The condensation of the helium mash was done in an integrated Joule-Thomson circuit, which was part of the dilution unit. The composition of the dilution unit was standard, but its components (still, heat exchangers, mixing chamber) were designed for high 3He flow. For thermometry, calibrated RuO chip resistance thermometers were available. In order to condense the mixture before an experiment, the fridge was operated like a Joule-Thomson liquefier with a relatively high inlet pressure (4 bar), where the liquid fraction of the circulating 3,4He mixture was accumulated in the dilution unit. The condensation took about 2 hours, and after 2 more hours of running, the temperature of the mixing chamber approached its minimum temperature of 10 mK. The maximum flow rate of the fridge was 1 mmol/s, and the refrigeration capacity of the mixing chamber was 700 μW at 100 mK. High cooling capacity, ease of operation and reliability distinguish this type of milli-Kelvin cooler.

  14. Dilution refrigeration for space applications

    NASA Technical Reports Server (NTRS)

    Israelsson, U. E.; Petrac, D.

    1990-01-01

    Dilution refrigerators are presently used routinely in ground based applications where temperatures below 0.3 K are required. The operation of a conventional dilution refrigerator depends critically on the presence of gravity. To operate a dilution refrigerator in space many technical difficulties must be overcome. Some of the anticipated difficulties are identified in this paper and possible solutions are described. A single cycle refrigerator is described conceptually that uses forces other than gravity to function and the stringent constraints imposed on the design by requiring the refrigerator to function on the earth without using gravity are elaborated upon.

  15. Infinite Maxwell fisheye inside a finite circle

    NASA Astrophysics Data System (ADS)

    Liu, Yangjié; Chen, Huanyang

    2015-12-01

    This manuscript proposes a two-dimensional heterogeneous imaging medium composed of an isotropic refractive index. We exploit conformal-mapping to transfer the full Maxwell fisheye into a finite circle. Unlike our previous design that requires a mirror of Zhukovski airfoil shape, this approach can work without a mirror, while offering a comparable imaging resolution. This medium may also be used as an isotropic gradient index lens to transform a light source inside it into two identical sources of null interference. A merit of this approach is reduction of the near-zero-index area from an infinite zone into a finite one, which shall ease its realization.

  16. The Great Celestial Numbers - The Infinitely Big and The Infinitely Small

    NASA Astrophysics Data System (ADS)

    Teodorani, M.

    2009-11-01

    This book is a travel that brings the reader to penetrate dimensionally the infinitely small and the infinitely large in the Universe, ranging from quarks to galaxies, and to compare these extreme numbers with the numbers that people encounters in normal life here on Earth. Several numerical examples are illustrated all over the text in a sort of scientific orienteering that describes dimensionally the realms of space, time and energy. The last part of the book shows how all spatial and temporal dimensions disappear when the mechanism of quantum entanglement is considered.

  17. Dilution jet mixing program, supplementary report

    NASA Technical Reports Server (NTRS)

    Srinivasan, R.; White, C.

    1986-01-01

    The velocity and temperature distributions predicted by a 3-D numerical model and experimental measurements are compared. Empirical correlations for the jet velocity trajectory developed are presented. The measured velocity distributions for all test cases of phase through phase 3 are presented in the form of contour and oblique plots. quantification of the effects of the following on the jet mixing characteristics with a confined crossflow are: (1) orifice geometry momentum flux ratio and density ratio; (2) nonuniform mainstream temperature and velocity profiles upstream of dilution orifices; (3) cold versus hot jet injection; (4) cross-stream flow are a convergence as encountered in practical dilution zone geometries; (5) 2-D slot versus circular orifices; (6) discrete noncirculcer orifices; (7) single-sided versus opposed jets; (8) single row of jets.

  18. Intermittency in dilute granular flows

    NASA Astrophysics Data System (ADS)

    Guo, Wenxuan; Zhang, Qiang; Wylie, Jonathan J.

    2016-07-01

    In this letter, we show that dilute granular systems can exhibit a type of intermittency that has no analogue in gas dynamics. We consider a simple system in which a very dilute set of granular particles falls under gravity through a nozzle. This setting is analogous to the classical problem of high-speed nozzle flow in the study of compressible gases. It is well known that very dilute granular systems exhibit behavior qualitatively similar to gases, and that gas flowing through a nozzle does not exhibit intermittency. Nevertheless, we show that the intermittency in dilute granular nozzle flows can occur and corresponds to complicated transitions between supersonic and subsonic regimes. We also provide detailed explanations of the mechanism underlying this phenomenon.

  19. Accurate measurements of thermodynamic properties of solutes in ionic liquids using inverse gas chromatography.

    PubMed

    Mutelet, Fabrice; Jaubert, Jean-Noël

    2006-01-13

    Activity coefficients at infinite dilution of 29 organic compounds in two room temperature ionic liquids were determined using inverse gas chromatography. The measurements were carried out at different temperatures between 323.15 and 343.15K. To establish the influence of concurrent retention mechanisms on the accuracy of activity coefficients at infinite dilution for 1-butyl-3-methylimidazolium octyl sulfate and 1-ethyl-3-methylimidazolium tosylate, phase loading studies of the net retention volume per gram of packing as a function of the percent phase loading were used. It is shown that most of the solutes are retained largely by partition with a small contribution from adsorption on 1-butyl-3-methylimidazolium octyl sulfate and that the n-alkanes are retained predominantly by interfacial adsorption on 1-ethyl-3-methylimidazolium tosylate. PMID:16310203

  20. 3D magnetometer for a dilution refrigerator

    NASA Astrophysics Data System (ADS)

    Uchaikin, S.; Likhachev, A.; Cioata, F.; Perminov, I.; Sanghera, H.; Singh, I.; Spear, P.; Chavez, P.; Han, X.; Petroff, C.; Rich, C.

    2012-12-01

    In this report, we describe a development of a three dimensional system for measurements of magnetic field at a wide temperature range of 300K-4K. The system is based on 8 AMR sensors and allows for control of the magnetic environment in a dilution refrigerator during the cool down of a superconducting processor. With a low noise signal processing electronics and a special sensor saturation circuit, a magnetic induction resolution below of 1 nT was achieved.

  1. Configuration interaction calculations with infinite angular = expansions

    SciTech Connect

    Goldman, S.P.; Glickman, T.

    1996-05-01

    The Modified Configuration Interaction (MCI) method improves the angular convergence of Configuration Interaction (CI) calculations by several orders of magnitude by mixing a priori a large number of angular basis functions. With MCI one can therefore use basis functions with very large angular momentum quantum numbers, overcoming an important limitation of conventional CI. Although this is desirable given the excellent convergence obtained, the large number of angular integrations and the calculation of n-j symbols with large values of l to high accuracy, make the angular calculations lengthy. In this work a new angular representation for CI calculations is presented that is much more efficient and powerful. Instead of the large number of angular functions of MCI the authors use a basis set containing an infinite linear combination of angular functions. All the necessary integrations involving these infinite expansions are done in closed form and are actually easy and fast to compute. The linear coefficients in the angular expansion are optimized in terms of a few non-linear parameters. Several examples will be presented with applications to two-electron systems.

  2. Infinite densities for Lévy walks

    NASA Astrophysics Data System (ADS)

    Rebenshtok, A.; Denisov, S.; Hänggi, P.; Barkai, E.

    2014-12-01

    Motion of particles in many systems exhibits a mixture between periods of random diffusive-like events and ballistic-like motion. In many cases, such systems exhibit strong anomalous diffusion, where low-order moments <|x (t ) |q> with q below a critical value qc exhibit diffusive scaling while for q >qc a ballistic scaling emerges. The mixed dynamics constitutes a theoretical challenge since it does not fall into a unique category of motion, e.g., the known diffusion equations and central limit theorems fail to describe both aspects. In this paper we resolve this problem by resorting to the concept of infinite density. Using the widely applicable Lévy walk model, we find a general expression for the corresponding non-normalized density which is fully determined by the particles velocity distribution, the anomalous diffusion exponent α , and the diffusion coefficient Kα. We explain how infinite densities play a central role in the description of dynamics of a large class of physical processes and discuss how they can be evaluated from experimental or numerical data.

  3. QUANTIFYING THE EFFECTS OF THE MIXING PROCESS IN FABRICATED DILUTION SYSTEMS ON PARTICULATE EMISSION MEASUREMENTS VIA AN INTEGRATED EXPERIMENTAL AND MODELING APPROACH

    EPA Science Inventory

    Mixture properties vs Aerodynamic properties
     
    Considering a number of parameters influencing particulate emission measurements, we first categorize them into two groups based on their characteristics, i.e., to mixture propertie...

  4. Atmospheric evolution of sulfur emissions from Kı̅lauea: real-time measurements of oxidation, dilution, and neutralization within a volcanic plume.

    PubMed

    Kroll, Jesse H; Cross, Eben S; Hunter, James F; Pai, Sidhant; Wallace, Lisa M M; Croteau, Philip L; Jayne, John T; Worsnop, Douglas R; Heald, Colette L; Murphy, Jennifer G; Frankel, Sheila L

    2015-04-01

    The high atmospheric concentrations of toxic gases, particulate matter, and acids in the areas immediately surrounding volcanoes can have negative impacts on human and ecological health. To better understand the atmospheric fate of volcanogenic emissions in the near field (in the first few hours after emission), we have carried out real-time measurements of key chemical components of the volcanic plume from Kı̅lauea on the Island of Hawai'i. Measurements were made at two locations, one ∼ 3 km north-northeast of the vent and the other 31 km to the southwest, with sampling at each site spanning a range of meteorological conditions and volcanic influence. Instrumentation included a sulfur dioxide monitor and an Aerosol Chemical Speciation Monitor, allowing for a measurement of the partitioning between the two major sulfur species (gas-phase SO2 and particulate sulfate) every 5 min. During trade wind conditions, which sent the plume toward the southwest site, sulfur partitioning exhibited a clear diurnal pattern, indicating photochemical oxidation of SO2 to sulfate; this enabled the quantitative determination of plume age (5 h) and instantaneous SO2 oxidation rate (2.4 × 10(-6) s(-1) at solar noon). Under stagnant conditions near the crater, the extent of SO2 oxidation was substantially higher, suggesting faster oxidation. The particles within the plume were extremely acidic, with pH values (controlled largely by ambient relative humidity) as low as -0.8 and strong acidity (controlled largely by absolute sulfate levels) up to 2200 nmol/m(3). The high variability of sulfur partitioning and particle composition underscores the chemically dynamic nature of volcanic plumes, which may have important implications for human and ecological health. PMID:25734883

  5. Statistical Mechanics of Infinite Gravitating Systems

    NASA Astrophysics Data System (ADS)

    Saslaw, William C.

    2008-01-01

    The cosmological many-body problem was stated over 300 years ago, but its solution is quite recent and still incomplete. Imagine an infinite expanding universe essentially containing a very large number of objects moving in response to their mutual gravitational forces. What will be the spatial and velocity distributions of these objects and how will they evolve? This question fascinates on many levels. Though inherently non-linear, it turns out to be one of the few analytically solvable problems of statistical mechanics with long range forces. The partition function can be calculated. From this all the thermodynamic properties of the system can be obtained for the grand canonical ensemble. They confirm results derived independently directly from the first and second laws of thermodynamics. The behavior of infinite gravitating systems is quite different from their finite relations such as star clusters. Infinite gravitating systems have regimes of negative specific heat, an unusual type of phase transition, and a very close relation to the observed large-scale structure of our universe. This last feature provides an additional astronomical motivation, especially since the statistical mechanics may be generalized to include effects of dark matter haloes around galaxies. Previously the cosmological many-body problem has mostly been studied using the BBGKY hierarchy (not so suitable in the non-linear regime) and by direct computer integrations of the objects' orbits. The statistical mechanics agrees with and substantially extends these earlier results. Most astrophysicists had previously thought that a statistical thermodynamic approach would not be applicable because: a) many-body gravitational systems have no rigorous equilibrium state, b) the unshielded nature of the long-range force would cause the partition function to diverge on large scales, and c) point masses would produce divergences on small scales. However, deeper considerations show that these are not

  6. Simulating infinite vortex lattices in superfluids

    NASA Astrophysics Data System (ADS)

    Mingarelli, Luca; Keaveny, Eric E.; Barnett, Ryan

    2016-07-01

    We present an efficient framework to numerically treat infinite periodic vortex lattices in rotating superfluids described by the Gross–Pitaevskii theory. The commonly used split-step Fourier (SSF) spectral methods are inapplicable to such systems as the standard Fourier transform does not respect the boundary conditions mandated by the magnetic translation group. We present a generalisation of the SSF method which incorporates the correct boundary conditions by employing the so-called magnetic Fourier transform. We test the method and show that it reduces to known results in the lowest-Landau-level regime. While we focus on rotating scalar superfluids for simplicity, the framework can be naturally extended to treat multicomponent systems and systems under more general ‘synthetic’ gauge fields.

  7. Nonlinear Shear Instabilities in an Infinite Slab

    NASA Astrophysics Data System (ADS)

    Nepveu, M.

    1982-08-01

    The dynamical evolution of an infinite slab moving in denser and noisy (turbulent) surroundings is investigated with a 2D hydrodynamic code. The applicability of the results to astrophysical jets is discussed. Inviscid beams show internal shocks at regular intervals of a few beamwidths. Kinks are not obvious. In viscous beams shocks are less outspoken, but turbulence is triggered with maximum scales of a few beamwidths. These viscous beams broaden. Linear stability analysis may hold up to a few e-folding times, although the seed disturbance field is not infinitesimal. The computations suggest that viscous astrophysical beams may become blurred quite suddenly and may give rise to sudden change in radiation patterns (NGC 1265).

  8. Infinite Index Subfactors and the GICAR Categories

    NASA Astrophysics Data System (ADS)

    Jones, Vaughan F. R.; Penneys, David

    2015-10-01

    Given a II1-subfactor of arbitrary index, we show that the rectangular GICAR category, also called the rectangular planar rook category, faithfully embeds as A - A bimodule maps among the bimodules . As a corollary, we get a lower bound on the dimension of the centralizer algebras for infinite index subfactors, and we also get that is nonabelian for , where is the Jones tower for . We also show that the annular GICAR/planar rook category acts as maps amongst the A-central vectors in , although this action may be degenerate. We prove these results in more generality using bimodules. The embedding of the GICAR category builds on work of Connes and Evans, who originally found GICAR algebras inside Temperley-Lieb algebras with finite modulus.

  9. Simulating infinite vortex lattices in superfluids.

    PubMed

    Mingarelli, Luca; Keaveny, Eric E; Barnett, Ryan

    2016-07-20

    We present an efficient framework to numerically treat infinite periodic vortex lattices in rotating superfluids described by the Gross-Pitaevskii theory. The commonly used split-step Fourier (SSF) spectral methods are inapplicable to such systems as the standard Fourier transform does not respect the boundary conditions mandated by the magnetic translation group. We present a generalisation of the SSF method which incorporates the correct boundary conditions by employing the so-called magnetic Fourier transform. We test the method and show that it reduces to known results in the lowest-Landau-level regime. While we focus on rotating scalar superfluids for simplicity, the framework can be naturally extended to treat multicomponent systems and systems under more general 'synthetic' gauge fields. PMID:27219843

  10. Simultaneous stable-isotope dilution GC-MS measurement of homoarginine, guanidinoacetate and their common precursor arginine in plasma and their interrelationships in healthy and diseased humans.

    PubMed

    Hanff, Erik; Kayacelebi, Arslan Arinc; Yanchev, Georgi Radoslavov; Maassen, Norbert; Haghikia, Arash; Tsikas, Dimitrios

    2016-03-01

    = 0.82, P < 0.0001) but did not correlate with hArg (r = 0.17, P = 0.52). The plasma concentrations of hArg, GAA and Arg measured in 9 patients suffering from stroke or transitory ischemic attack were 1.8 ± 0.6, 2.7 ± 0.4 and 82 ± 17 µM. The ratio values of the hArg, GAA and Arg concentrations measured after removal of plasma proteins by methanol precipitation or ultrafiltration were 0.94 ± 0.1, 0.94 ± 0.08, and 0.88 ± 0.07, respectively. Simultaneous measurement of hArg and GAA in human plasma may allow assessment of AGAT activity in vivo with respect both to GAA and to hArg and their relationship in health, disease, nutrition and pharmacotherapy. PMID:26573540

  11. Precision of a field method for determination of pH in dilute lakes

    USGS Publications Warehouse

    Turk, J.T.

    1986-01-01

    Replicate pH measurements in three dilute lakes made during extreme conditions indicate that pH can be measured in the field with a variance due to measurement error of 0.005 unit. Error of the field technique in measuring the pH of dilute solutions in the laboratory ranges from less than 0.01 unit in dilute strong-acid solutions to about 0.05 unit in air-saturated deionized water.

  12. Algebraic independence properties related to certain infinite products

    NASA Astrophysics Data System (ADS)

    Tanaka, Taka-aki

    2011-09-01

    In this paper we establish algebraic independence of the values of a certain infinite product as well as its all successive derivatives at algebraic points other than its zeroes, using the fact that the logarithmic derivative of an infinite product gives a partial fraction expansion. Such an infinite product is generated by a linear recurrence. The method used for proving the algebraic independence is based on the theory of Mahler functions of several variables.

  13. Urinary nitrite/nitrate ratio measured by isotope-dilution LC-MS/MS as a tool to screen for urinary tract infections.

    PubMed

    Chao, Mu-Rong; Shih, Ying-Ming; Hsu, Yu-Wen; Liu, Hung-Hsin; Chang, Yuan-Jhe; Lin, Bo-Huei; Hu, Chiung-Wen

    2016-04-01

    Urinary tract infections (UTIs) are the most common type of nosocomial infection. Traditionally, the presence of white blood cells and microorganisms in the urine provides objective evidence for UTI diagnosis. Here, we describe the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure the nitrite and nitrate levels in urine and investigate the potential of this method for UTI diagnosis. LC-MS/MS analysis was performed in positive electrospray ionization mode. After adding (15)N-labeled internal standards and derivatizing with 2,3-diaminonaphthalene (DAN), the urinary nitrite content was directly analyzed by LC-MS/MS, whereas the urinary nitrate was first reduced to nitrite before derivatization and LC-MS/MS analysis. The derivatization of nitrite and enzymatic reduction of nitrate were optimized. This method was then applied to 241 healthy subjects and 73 UTI patients. Optimization tests revealed that 1 mL of crude urine required at least 6.25 μmol of DAN to completely derivatize nitrite and 2.5 U of nitrate reductase to completely reduce nitrate to nitrite. Urinary analysis showed that the urinary concentration of nitrite and the nitrite/nitrate ratio were higher in UTI patients than in healthy subjects. Compared with the dipstick-based urinary nitrite test and using LC-MS/MS to determine the nitrite concentration (sensitivity: 23-25%), the nitrite/nitrate ratio was significantly more sensitive (95%) and exhibited a satisfactory specificity (91%) in the screening of UTIs. Taken together, the nitrite/nitrate ratio, which reflects the reducing ability of pathogenic bacteria, could be a better method for the diagnosis of UTIs that is not subject to variations in urine specimen quality. PMID:26829019

  14. Preparation, certification and validation of a stable solid spike of uranium and plutonium coated with a cellulose derivative for the measurement of uranium and plutonium content in dissolved nuclear fuel by isotope dilution mass spectrometry.

    PubMed

    Surugaya, Naoki; Hiyama, Toshiaki; Verbruggen, André; Wellum, Roger

    2008-02-01

    A stable solid spike for the measurement of uranium and plutonium content in nitric acid solutions of spent nuclear fuel by isotope dilution mass spectrometry has been prepared at the European Commission Institute for Reference Materials and Measurements in Belgium. The spike contains about 50 mg of uranium with a 19.838% (235)U enrichment and 2 mg of plutonium with a 97.766% (239)Pu abundance in each individual ampoule. The dried materials were covered with a thin film of cellulose acetate butyrate as a protective organic stabilizer to resist shocks encountered during transportation and to eliminate flaking-off during long-term storage. It was found that the cellulose acetate butyrate has good characteristics, maintaining a thin film for a long time, but readily dissolving on heating with nitric acid solution. The solid spike containing cellulose acetate butyrate was certified as a reference material with certified quantities: (235)U and (239)Pu amounts and uranium and plutonium amount ratios, and was validated by analyzing spent fuel dissolver solutions of the Tokai reprocessing plant in Japan. This paper describes the preparation, certification and validation of the solid spike coated with a cellulose derivative. PMID:18270417

  15. Performance and System Validation of a New Cellular-Enabled Blood Glucose Monitoring System Using a New Standard Reference Measurement Procedure of Isotope Dilution UPLC-MRM Mass Spectrometry

    PubMed Central

    Angelides, Kimon; Matsunami, Risë K.; Engler, David A.

    2015-01-01

    Background: We evaluated the accuracy, precision, and linearity of the In Touch® blood glucose monitoring system (BGMS), a new color touch screen and cellular-enabled blood glucose meter, using a new rapid, highly precise and accurate 13C6 isotope-dilution liquid chromatography-mass spectrometry method (IDLC-MS). Methods: Blood glucose measurements from the In Touch® BGMS were referenced to a validated UPLC-MRM standard reference measurement procedure previously shown to be highly accurate and precise. Readings from the In Touch® BGMS were taken over the blood glucose range of 24-640 mg/dL using 12 concentrations of blood glucose. Ten In Touch® BGMS and 3 lots of test strips were used with 10 replicates at each concentration. A lay user study was also performed to assess the ease of use. Results: At blood glucose concentrations <75 mg/dL 100% of the measurements are within ±8 mg/dL from the true reference standard; at blood glucose levels >75 mg/dL 100% of the measurements are within ±15% of the true reference standard. 100% of the results are within category A of the consensus grid. Within-run precision show CV < 3.72% between 24-50 mg/dL and CV<2.22% between 500 and 600 mg/dL. The results show that the In Touch® meter exceeds the minimum criteria of both the ISO 15197:2003 and ISO 15197:2013 standards. The results from a user panel show that 100% of the respondents reported that the color touch screen, with its graphic user interface (GUI), is well labeled and easy to navigate. Conclusions: To our knowledge this is the first touch screen glucose meter and the first study where accuracy of a new BGMS has been measured against a true primary reference standard, namely IDLC-MS. PMID:26002836

  16. Infinite invariant density determines statistics of time averages for weak chaos.

    PubMed

    Korabel, N; Barkai, E

    2012-02-10

    Weakly chaotic nonlinear maps with marginal fixed points have an infinite invariant measure. Time averages of integrable and nonintegrable observables remain random even in the long time limit. Temporal averages of integrable observables are described by the Aaronson-Darling-Kac theorem. We find the distribution of time averages of nonintegrable observables, for example, the time average position of the particle, x[over ¯]. We show how this distribution is related to the infinite invariant density. We establish four identities between amplitude ratios controlling the statistics of the problem. PMID:22401047

  17. Dynamics of Bubbles Rising in Finite and Infinite Media

    SciTech Connect

    C.C. Maneri; P.F. Vassallo

    2000-10-27

    The dynamic behavior of single bubbles rising in quiescent liquid Suva (R134a) in a duct has been examined through the use of a high speed video system. Size, shape and velocity measurements obtained with the video system reveal a wide variety of characteristics for the bubbles as they rise in both finite and infinite media. This data, coupled with previously published data for other working fluids, has been used to assess and extend a rise velocity model given by Fan and Tsuchiya. As a result of this assessment, a new rise velocity model has been developed which maintains the physically consistent characteristics of the surface tension in the distorted bubbly regime. In addition, the model is unique in that it covers the entire range of bubble sizes contained in the spherical, distorted and planar slug regimes.

  18. Propagation of SH waves in an infinite/semi-infinite piezoelectric/piezomagnetic periodically layered structure.

    PubMed

    Pang, Yu; Liu, Yu-Shan; Liu, Jin-Xi; Feng, Wen-Jie

    2016-04-01

    In this paper, SH bulk/surface waves propagating in the corresponding infinite/semi-infinite piezoelectric (PE)/piezomagnetic (PM) and PM/PE periodically layered composites are investigated by two methods, the stiffness matrix method and the transfer matrix method. For a semi-infinite PE/PM or PM/PE medium, the free surface is parallel to the layer interface. Both PE and PM materials are assumed to be transversely isotropic solids. Dispersion equations are derived by the stiffness/transfer matrix methods, respectively. The effects of electric-magnetic (ME) boundary conditions at the free surface and the layer thickness ratios on dispersion curves are considered in detail. Numerical examples show that the results calculated by the two methods are the same. The dispersion curves of SH surface waves are below the bulk bands or inside the frequency gaps. The ratio of the layer thickness has an important effect not only on the bulk bands but also on the dispersion curves of SH surface waves. Electric and magnetic boundary conditions, respectively, determine the dispersion curves of SH surface waves for the PE/PM and PM/PE semi-infinite structures. The band structures of SH bulk waves are consistent for the PE/PM and PM/PE structures, however, the dispersive behaviors of SH surface waves are indeed different for the two composites. The realization of the above-mentioned characteristics of SH waves will make it possible to design PE/PM acoustic wave devices with periodical structures and achieve the better performance. PMID:26836289

  19. Measurement of urinary desmosine by isotope dilution and high performance liquid chromatography. Correlation between elastase-induced air-space enlargement in the hamster and elevation of urinary desmosine

    SciTech Connect

    Stone, P.J.; Bryan-Rhadfi, J.; Lucey, E.C.; Ciccolella, D.E.; Crombie, G.; Faris, B.; Snider, G.L.; Franzblau, C. )

    1991-08-01

    The accuracy of methods employed to measure the elastin-specific crosslinks, desmosine (DES) and isodesmosine (IDES), has been called into question because contaminants in the urine may cause elevated values. In the present study urine samples were spiked with a known amount of (14C)DES and refluxed in 6 N HCl. Sephadex G-15 chromatography of the hydrolyzed urine employed to remove contaminants. DES and IDES were quantified by high performance liquid chromatography (HPLC) as well as by amino acid analysis. The amount of isotope recovered was used to determine losses during the overall procedure and the isotope dilution to calculate the amounts of endogenous DES and IDES originally present in the urine. Because similar values were obtained by both methods, the more rapid HPLC method was used for all succeeding analyses. In one experiment, the DES amounts in urine collected from hamsters for 3 days after intratracheal treatment with human neutrophil elastase (300 micrograms) or porcine pancreatic elastase (300 micrograms) were 0.212 {plus minus} 0.012 (mean {plus minus} SEM, two measurements on a single pool) and 0.816 {plus minus} 0.005 (two measurements) microgram per hamster per day, respectively. Urine from control hamsters had a mean value of 0.074 {plus minus} 0.008 (eight measurements) microgram per hamster per day. The HNE- and PPE-treated hamsters had mean linear intercept values of 119 and 159% of control values, respectively, giving a positive correlation between increase in airspace size and elevation of urinary DES.

  20. Infinite networks and variation of conductance functions in discrete Laplacians

    NASA Astrophysics Data System (ADS)

    Jorgensen, Palle; Tian, Feng

    2015-04-01

    For a given infinite connected graph G = (V, E) and an arbitrary but fixed conductance function c, we study an associated graph Laplacian Δc; it is a generalized difference operator where the differences are measured across the edges E in G; and the conductance function c represents the corresponding coefficients. The graph Laplacian (a key tool in the study of infinite networks) acts in an energy Hilbert space ℋE computed from c. Using a certain Parseval frame, we study the spectral theoretic properties of graph Laplacians. In fact, for fixed c, there are two versions of the graph Laplacian, one defined naturally in the l2 space of V and the other in ℋE. The first is automatically selfadjoint, but the second involves a Krein extension. We prove that, as sets, the two spectra are the same, aside from the point 0. The point zero may be in the spectrum of the second, but not the first. We further study the fine structure of the respective spectra as the conductance function varies, showing now how the spectrum changes subject to variations in the function c. Specifically, we study an order on the spectra of the family of operators Δc, and we compare it to the ordering of pairs of conductance functions. We show how point-wise estimates for two conductance functions translate into spectral comparisons for the two corresponding graph Laplacians, involving a certain similarity: We prove that point-wise ordering of two conductance functions c on E induces a certain similarity of the corresponding (Krein extensions computed from the) two graph Laplacians Δc. The spectra are typically continuous, and precise notions of fine-structure of spectrum must be defined in terms of equivalence classes of positive Borel measures (on the real line). Our detailed comparison of spectra is analyzed this way.

  1. Assessment of the amount of body water in the Red Knot (Calidris canutus): an evaluation of the principle of isotope dilution with 2H, (17)O, and (18)O as measured with laser spectrometry and isotope ratio mass spectrometry.

    PubMed

    Kerstel, Erik R T; Piersma, Theunis; Piersma, Theunis A J; Gessaman, James A; Gessaman, G Jim; Dekinga, Anne; Meijer, Harro A J; Visser, G Henk

    2006-03-01

    We have used the isotope dilution technique to study changes in the body composition of a migratory shorebird species (Red Knot, Calidris canutus) through an assessment of the amount of body water in it. Birds were quantitatively injected with a dose of water with elevated concentrations of 2H, (17)O, and (18)O. Thereafter, blood samples were taken and distilled. The resulting water samples were analysed using an isotope ratio mass spectrometry (for 2H and (18)O only) and a stable isotope ratio infrared laser spectrometry (2H, (17)O, and (18)O) to yield estimates of the amount of body water in the birds, which in turn could be correlated to the amount of body fat. Here, we validate laser spectrometry against mass spectrometry and show that all three isotopes may be used for body water determinations. This opens the way to the extension of the doubly labelled water method, used for the determination of energy expenditure, to a triply labelled water method, incorporating an evaporative water loss correction on a subject-by-subject basis or, alternatively, the reduction of the analytical errors by statistically combining the (17)O and (18)O measurements. PMID:16500750

  2. Field observations of dilution on the Ipanema Beach outfall.

    PubMed

    Roldão, J; Carvalho, J L; Roberts, P J

    2001-01-01

    Field observations of the Ipanema Beach, Rio de Janeiro, ocean sewage outfall are presented. Measurements of dilution and other wastefield characteristics were obtained by adding dye tracer to the effluent and measuring in-situ. Simultaneous measurements of oceanographic conditions were made by Acoustic Doppler Current Profilers, thermistor strings, and profiling instruments. Four experiments were performed, two during unstratified conditions when the plume was surfacing, and two during conditions of strong stratification when the plume was submerged. The minimum dilution varied from 30 to 130. The measurements reflect the worst case conditions as the campaigns were all made for weak currents. PMID:11443984

  3. Solenoid magnetic fields calculated from superposed semi-infinite solenoids

    NASA Technical Reports Server (NTRS)

    Brown, G. V.; Flax, L.

    1966-01-01

    Calculation of a thick solenoid coils magnetic field components is made by a superposition of the fields produced by four solenoids of infinite length and zero inner radius. The field produced by this semi-infinite solenoid is dependent on only two variables, the radial and axial field point coordinates.

  4. A New Look at Infinitives in Business and Technical Writing.

    ERIC Educational Resources Information Center

    Myers, Marshall

    2002-01-01

    Argues the infinitive phrase has not been taken seriously in writing because writers have been too concerned with Bishop Robert Lowth's proscription against the split infinitive. Notes that examination of three types of technical prose (instructions, annual reports, and "junk mail") reveals that more than one sentence in four contains an…

  5. Use of Physical Analogs to Evaluate Infinite Series.

    ERIC Educational Resources Information Center

    Epstein, D. J.; Smith, A. C.

    1979-01-01

    Discusses the paradoxes that can result when physical examples lead to infinite series. Two examples are presented: the Madelung energy of a one-dimensional array of alternating positive and negative charges, and a point charge between infinite parallel plates. (BB)

  6. Infinite statistics condensate as a model of dark matter

    SciTech Connect

    Ebadi, Zahra; Mirza, Behrouz; Mohammadzadeh, Hosein E-mail: b.mirza@cc.iut.ac.ir

    2013-11-01

    In some models, dark matter is considered as a condensate bosonic system. In this paper, we prove that condensation is also possible for particles that obey infinite statistics and derive the critical condensation temperature. We argue that a condensed state of a gas of very weakly interacting particles obeying infinite statistics could be considered as a consistent model of dark matter.

  7. The Infinite Challenge: Levels of Conceiving the Endlessness of Numbers

    ERIC Educational Resources Information Center

    Falk, Ruma

    2010-01-01

    To conceive the infinity of integers, one has to realize: (a) the unending possibility of increasing/decreasing numbers (potential infinity), (b) that the cardinality of the set of numbers is greater than that of any finite set (actual infinity), and (c) that the leap from a finite to an infinite set is itself infinite (immeasurable gap). Three…

  8. Axion cosmology, lattice QCD and the dilute instanton gas

    NASA Astrophysics Data System (ADS)

    Borsanyi, Sz.; Dierigl, M.; Fodor, Z.; Katz, S. D.; Mages, S. W.; Nogradi, D.; Redondo, J.; Ringwald, A.; Szabo, K. K.

    2016-01-01

    Axions are one of the most attractive dark matter candidates. The evolution of their number density in the early universe can be determined by calculating the topological susceptibility χ (T) of QCD as a function of the temperature. Lattice QCD provides an ab initio technique to carry out such a calculation. A full result needs two ingredients: physical quark masses and a controlled continuum extrapolation from non-vanishing to zero lattice spacings. We determine χ (T) in the quenched framework (infinitely large quark masses) and extrapolate its values to the continuum limit. The results are compared with the prediction of the dilute instanton gas approximation (DIGA). A nice agreement is found for the temperature dependence, whereas the overall normalization of the DIGA result still differs from the non-perturbative continuum extrapolated lattice results by a factor of order ten. We discuss the consequences of our findings for the prediction of the amount of axion dark matter.

  9. Strongly-correlated fermionic matter in the dilute limit

    SciTech Connect

    Mihaila, Bogdan; Cardenas, Andres L

    2008-01-01

    We study 'the ground-state properties of the many-body system composed of spin-l/2 fermions interacting via a zero-range, infinite scattering length contact interaction.' Sometimes referred to as the George Bertsch problem, it is of particular interest in astrophysics in connection with the equation of state for neutron matter and has been revisited recently with the advent of experimental studies of the BCS to BEC crossover in ultracold fermionic atom gases. We will show that new insights into the solution to this problem are obtained in the context of a coupled-cluster (exp S) expansion approach to calculating the equation of state for dilute fermionic systems and that present state-of-the-art Monte Carlo calculations have not yet provided the definitive answer.

  10. Countable Infinite Sets and Inflationary Models

    NASA Astrophysics Data System (ADS)

    Berezin, Alexander A.

    2000-04-01

    Unreasonable effectiveness of mathematics (E.Wigner) recasts pythagorean "all things are made of numbers". Hypotheses of eternal inflation (A.Linde) and/or quantum branching (H.Everett) buttressed by platonic pressure principle (PPP) resonates with "for deriving all from nothing there suffices a single principle" (G.W.Leibnitz). Externalization of PPP uses patterns of factorizations of super-long integers (tower exponents, TE). PPP-TE explosive emergence of space-time-matter-energy rests on infinite complexity of factorizational and iterational patterns of integers. Thus, PPP is direct translation of metaphysical principle to physics of material world ("metaphysics works"). Countability of quantum states of bounded systems allows "listing" of all states of all baby universes through Godel-like counting with TE of primes. At each breeding step upper (Nth) prime of TE stack p1...pN counts (by multidimensional Cantor diagonal scheme) all universes AND all states in them. Exclusive use of primes in TEs assures non-overlapping counting. Cantor counting with non-crossing subsets of primes (and actual PPP emergence) can proceed both in "forward" and "backward" direction in megauniversal ("Newtonian") time. format.