WorldWideScience

Sample records for dilution activity coefficient

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

    Energy Technology Data Exchange (ETDEWEB)

    Awe, O.E., E-mail: draweoe2004@yahoo.com; Oshakuade, O.M.

    2016-04-15

    A new method for calculating Infinite Dilute Activity Coefficients (γ{sup ∞}s) of binary liquid alloys has been developed. This method is basically computing γ{sup ∞}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{sup ∞}s of 10 binary alloys whose γ{sup ∞}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{sup ∞}s are either nonexistent or incomplete. In order to verify the reliability of the computed γ{sup ∞}s of the 22 selected alloys, we recomputed the γ{sup ∞}s using three other existing methods of computing or estimating γ{sup ∞}s and then used the γ{sup ∞}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{sup ∞}s of binary liquid alloys.

  2. Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate

    International Nuclear Information System (INIS)

    Domanska, Urszula; Krolikowska, Marta; Acree, William E.; Baker, Gary A.

    2011-01-01

    Research highlights: → Measurements of activity coefficients at infinite dilution using GLC. → 36 organic solvents and water in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate, [EMIM][TCB]. → Possible entrainer for different separation processes. → The partial molar excess thermodynamic functions at infinite dilution were calculated. - Abstract: The activity coefficients at infinite dilution, γ 13 ∞ , for 36 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, ethers, acetone, and water, in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate, [EMIM][TCB], were determined by gas-liquid chromatography at temperatures from 298.15 K to 358.15 K. These values are compared to those previously published for selected solutes in the same ionic liquid. The values of the partial molar excess Gibbs free energy ΔG 1 E,∞ , enthalpy ΔH 1 E,∞ , and entropy ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. Three gas-liquid partition coefficients, K L were calculated for all solutes and the Abraham solvation parameter model is discussed. The values of the selectivity for different separation problems were calculated from γ 13 ∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, 1-decyl-3-methylimidazolium tetracyanoborate, [DMIM][TCB], and additional ionic liquids.

  3. Prediction of activity coefficients at infinite dilution for organic solutes in ionic liquids by artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Nami, Faezeh [Department of Chemistry, Shahid Beheshti University, G.C., Evin-Tehran 1983963113 (Iran, Islamic Republic of); Deyhimi, Farzad, E-mail: f-deyhimi@sbu.ac.i [Department of Chemistry, Shahid Beheshti University, G.C., Evin-Tehran 1983963113 (Iran, Islamic Republic of)

    2011-01-15

    To our knowledge, this work illustrates for the first time the ability of artificial neural network (ANN) to predict activity coefficients at infinite dilution for organic solutes in ionic liquids (ILs). Activity coefficient at infinite dilution ({gamma}{sup {infinity}}) is a useful parameter which can be used for the selection of effective solvent in the separation processes. Using a multi-layer feed-forward network with Levenberg-Marquardt optimization algorithm, the resulting ANN model generated activity coefficient at infinite dilution data over a temperature range of 298 to 363 K. The unavailable input data concerning softness (S) of organic compounds (solutes) and dipole moment ({mu}) of ionic liquids were calculated using GAMESS suites of quantum chemistry programs. The resulting ANN model and its validation are based on the investigation of up to 24 structurally different organic compounds (alkanes, alkenes, alkynes, cycloalkanes, aromatics, and alcohols) in 16 common imidazolium-based ionic liquids, at different temperatures within the range of 298 to 363 K (i.e. a total number of 914 {gamma}{sub Solute}{sup {infinity}}for each IL data point). The results show a satisfactory agreement between the predicted ANN and experimental data, where, the root mean square error (RMSE) and the determination coefficient (R{sup 2}) of the designed neural network were found to be 0.103, 0.996 for training data and 0.128, 0.994 for testing data, respectively.

  4. Prediction of activity coefficients at infinite dilution for organic solutes in ionic liquids by artificial neural network

    International Nuclear Information System (INIS)

    Nami, Faezeh; Deyhimi, Farzad

    2011-01-01

    To our knowledge, this work illustrates for the first time the ability of artificial neural network (ANN) to predict activity coefficients at infinite dilution for organic solutes in ionic liquids (ILs). Activity coefficient at infinite dilution (γ ∞ ) is a useful parameter which can be used for the selection of effective solvent in the separation processes. Using a multi-layer feed-forward network with Levenberg-Marquardt optimization algorithm, the resulting ANN model generated activity coefficient at infinite dilution data over a temperature range of 298 to 363 K. The unavailable input data concerning softness (S) of organic compounds (solutes) and dipole moment (μ) of ionic liquids were calculated using GAMESS suites of quantum chemistry programs. The resulting ANN model and its validation are based on the investigation of up to 24 structurally different organic compounds (alkanes, alkenes, alkynes, cycloalkanes, aromatics, and alcohols) in 16 common imidazolium-based ionic liquids, at different temperatures within the range of 298 to 363 K (i.e. a total number of 914 γ Solute ∞ for each IL data point). The results show a satisfactory agreement between the predicted ANN and experimental data, where, the root mean square error (RMSE) and the determination coefficient (R 2 ) of the designed neural network were found to be 0.103, 0.996 for training data and 0.128, 0.994 for testing data, respectively.

  5. Measurement of infinite dilution activity coefficient and application of modified ASOG model for solvent-polymer systems

    Energy Technology Data Exchange (ETDEWEB)

    Choi, B.; Choi, J. [Kwangwoon University, Seoul (Korea, Republic of); Tochigi, K.; Kojima, K. [Nihon University, Tokyo (Japan)

    1996-04-20

    A gas chromatographic method was used in order to measure vapor-liquid equilibria for solvent (1)-polymer (2) systems in which the polymers were polystyrene, poly(a-methyl) styrene and the advents were benzene toluene cyclohexane methylisobutylketone, ethylacetate, and vinylacetate. The activity coefficients of solvents for solvent (1)-polymer (2) systems were measured at infinite dilution and the modified ASOG (Analytical Solution of Group) model was suggested to describe vapor-liquid equilibria of those systems within a range of temperatures 423.15K through 498.15K. The model consists of the original ASOG and the free volume term. An external degree of freedom in the free volume term empirically became to a C1={alpha}+{beta}/T as a function of temperature. Each tern in the modified ASOG model is based on the weight fraction. The external degree of freedom in the model was estimated by experimental data within a range of temperatures. As a result of doing it the infinite dilution activity coefficients calculated were agreed with the experimental data within an error of 0.1%. 27 refs., 3 figs., 7 tabs.

  6. Activity coefficients at infinite dilution of hydrocarbons in glycols: Experimental data and thermodynamic modeling with the GCA-EoS

    International Nuclear Information System (INIS)

    González Prieto, Mariana; Williams-Wynn, Mark D.; Bahadur, Indra; Sánchez, Francisco A.; Mohammadi, Amir H.

    2017-01-01

    Highlights: • Experimental infinite dilution activity coefficients of hydrocarbons in glycols. • Inverse gas-liquid chromatography technique. • Solutes investigated include n-alkanes, 1-alkenes, and cycloalkanes. • Highly non-ideal systems are modeled with the GCA-EoS. - Abstract: The infinite dilution activity coefficients for 12 non-polar hydrocarbon solutes in the solvents, monoethylene and diethylene glycol, were measured using the gas-liquid chromatography technique. Pre-saturation of the carrier gas was required to avoid solvent loss from the chromatographic column during the measurements that were carried out at T = (303.15, 313.15 and 323.15) K for monoethylene glycol and at T = (304.15, 313.15 and 323.15) K for diethylene glycol. The solutes investigated include n-alkanes, 1-alkenes, and cycloalkanes. The new data are compared with the highly scattered data that is available in the open literature. Finally, these highly non-ideal systems are modeled with the GCA-EoS.

  7. Activity coefficients at infinite dilution and enthalpies of solution of methanol, 1-butanol, and 1-hexanol in 1-hexyl-3-methyl-imidazolium bis(trifluoromethyl-sulfonyl) imide

    International Nuclear Information System (INIS)

    Heintz, Andreas; Verevkin, Sergey P.; Lehmann, Jochen K.; Vasiltsova, Tatiana V.; Ondo, Daniel

    2007-01-01

    Activity coefficients at infinite dilution γ i ∼ of methanol, 1-butanol, and 1-hexanol in the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoromethyl-sulfonyl) imide ([HMIM][NTf 2 ]) have been determined by gas chromatography using the ionic liquids as stationary phase. The measurements were carried out at different temperatures between 298K and 396K. From the temperature dependence of the limiting activity coefficients partial molar excess enthalpies at infinite dilution H i E,∼ of the alcohol in the ionic liquid have been derived. Additionally, enthalpies of solution of the same alcohols in the [HMIM][NTf 2 ] have been measured at T=298.15K in the range of low concentrations using titration calorimetry. Results at infinite dilution, H i E,∼ , are compared with those indirectly obtained from activity coefficients in infinite dilution γ i ∼ . Within the experimental error of both methods thermodynamic consistency has been confirmed

  8. Activity coefficients at infinite dilution of organic solutes in 1-hexyl-3-methylimidazolium trifluoroacetate and influence of interfacial adsorption using gas–liquid chromatography

    International Nuclear Information System (INIS)

    Jiang, Lin-Kun; Wang, Li-Sheng; Du, Chao-Jun; Wang, Xue-Yuan

    2014-01-01

    Highlights: • Activity coefficients at infinite dilution of organic solutes in [HMIM][TFA] were determined. • The contribution of interfacial adsorption to the retention mechanism was estimated. • The partial molar excess enthalpies and the solubility parameters of [HMIM][TFA] were calculated. -- Abstract: Activity coefficients at infinite dilution for a series of organic solutes in the ionic liquid 1-hexyl-3-methylimidazolium trifluoroacetate ([HMIM][TFA]) have been determined by gas–liquid chromatography at the temperature range from (303.15 to 363.15) K. The contribution of interfacial adsorption to the retention mechanism was estimated by changing the loading of ionic liquid in stationary phase. The partial molar excess enthalpies at infinite dilution and the solubility parameters of ionic liquid were also calculated from the experimental values of activity coefficients at infinite dilution

  9. Activity coefficients at infinite dilution of organic solutes in diethylene glycol and triethylene glycol from gas–liquid chromatography

    International Nuclear Information System (INIS)

    Williams-Wynn, Mark D.; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

    2013-01-01

    Highlights: • γ 13 ∞ values reported for 25 organic solutes in the solvents DEG and TEG. • Measurements undertaken using the glc technique at T = (333.2, 348.2, and 363.2) K. • Measurements at elevated temperature possible by pre-saturation of carrier gas. • Comparison of DEG and TEG performance with a number of solvents. -- Abstract: The infinite dilution activity coefficients for 25 hydrocarbon solutes in diethylene glycol (DEG) and triethylene glycol (TEG) were measured using the gas–liquid chromatography technique with pre-saturation of the carrier gas. The hydrocarbon solutes included n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes and alkanols. At the temperatures at which measurements were conducted, the solvents were volatile, and pre-saturation was considered necessary. The measurements were made at T = (333.2, 348.2 and 363.2) K. Values of the selectivity and capacity relating to DEG and TEG, for two sets of mixtures, which are usually difficult to separate by distillation or solvent extraction, were calculated from the experimental results. The two sets of mixtures were: cyclohexane and benzene; and benzene and methanol. The results obtained in this work were then compared to values for other solvents, at similar temperatures, which were obtained or calculated from literature data

  10. Activity coefficients at infinite dilution for hydrocarbons in furfuryl alcohol at T=(278.15 and 298.15) K, determined by g.l.c

    International Nuclear Information System (INIS)

    Kozlowska, Marta K.; Letcher, Trevor M.; Domanska, Urszula

    2004-01-01

    The potential of the polar solvent, furfuryl alcohol, as a solvent in the separation of aromatics from aliphatics and other hydrocarbons, has been investigated by measuring activity coefficients at infinite dilution. The activity coefficients at infinite dilution for some alkanes, cycloalkanes, alkenes, alkynes and benzene in furfuryl alcohol have been determined by g.l.c. at T=(278.15 and 298.15) K. The method used is we believe, a more controlled and reliable method than the alternative pre-saturation method. The results have been used to calculate the selectivity factor and hence predict the potential for furfuryl alcohol as a solvent in separating aromatic compounds from aliphatic compounds and other hydrocarbons using extractive distillation. The results have been compared to the recently published work on a related polar solvent - furfural. The excess enthalpies of mixing at infinite dilution have also been calculated

  11. Measurement and correlation of infinite dilution activity coefficients of alcohols in hexadecane and tetradecane; Hexadecane oyobi tetradecane chu no alcohol rui no mugen kishaku katsuryo keisu no sokutei narabini sokan

    Energy Technology Data Exchange (ETDEWEB)

    Fukuchi, K.; Miyoshi, K. [Ube National College of Technology, Yamaguchi (Japan)

    1996-03-10

    The infinite dilution activity coefficients of alcohols (methanol, ethanol, 1-propanol, 2-propano, 1-butanol, and 2-butanol) in heavy paraffinic hydrocarbons (hexadecane and tetradecane) were measured in the region 20-80{degree}C by a gas stripping method. The ASOG model was applied to calculate the infinite dilution activity coefficients. The infinite dilution activity coefficients can be correlated by adjusting the group interaction parameters between hydroxy and methyl groups. 8 refs., 3 figs., 4 tabs.

  12. Accurate measurements of infinite dilution activity coefficients using gas chromatography with static-wall-coated open-tubular columns.

    Science.gov (United States)

    Xu, Qianqian; Su, Baogen; Luo, Xinyi; Xing, Huabin; Bao, Zongbi; Yang, Qiwei; Yang, Yiwen; Ren, Qilong

    2012-11-06

    Wall-coated open-tubular (WCOT) columns provide higher column efficiency and lower solute interfacial adsorption effect than packed columns. However, previous efforts used to measure the infinite dilution activity coefficient (γ(∞)) via a chromatographic technique have used packed columns, because the low carrier gas flow rate (U) and the small stationary phase amount (n(2)) in WCOT columns raise large errors. By rationally revising the γ(∞)-calculation equation for static-wall-coated open-tubular column, we observed that U and n(2) are not necessarily needed and the resulting error could be reduced, and WCOT column gas chromatography subsequently became a superior method for the accurate γ(∞) determination. In this study, we validate our revised γ(∞)-calculation equation by measuring γ(∞) in an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate system, in which 55 organic compounds covering a wide range of functional groups were used as probe solutes and their γ(∞) values in the ionic liquid were determined at 40.0, 50.0, and 60.0 °C. Experimental error analysis shows that our revised equation remarkably reduces the error compared to the common γ(∞)-calculation equation. Our data is consistent with previously reported values obtained via other techniques, which further proves the credibility of our revised equation. The accurately determined γ(∞) values can be directly used to calculate the partial molar excess enthalpy, selectivity, and capacity, which will benefit for the rapid screening of solvents (especially ionic liquids) in separation approaches.

  13. Measurement of Activity Coefficients at Infinite Dilution for Alcohols in [BMIM][CH3SO4] using HS-SPME/GC-FID

    Directory of Open Access Journals (Sweden)

    A. M. Elias

    Full Text Available ABSTRACT The activity coefficient at infinite dilution (&IN1 and distribution ratios at infinite dilution (&IN2 were determined for alkanols (methanol, ethanol, 1-propanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol in the ionic liquid (IL 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][CH3SO4] by HS-SPME (Headspace - Solid Phase Micro Extraction at four temperatures (298.15, 313.15, 333.15, and 353.15K using headspace - solid phase microextraction (SPME-HS. The results showed significant agreement with literature data. In addition, partial molar excess enthalpies at infinite dilution (&IN3, excess Gibbs energies (&IN4, and excess entropies (&IN5 were calculated from the (&IN6 values.

  14. Thermodynamics and activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-butyl-1-methylmorpholinium tricyanomethanide

    International Nuclear Information System (INIS)

    Domańska, Urszula; Lukoshko, Elena Vadimovna

    2014-01-01

    Highlights: • Measurements of activity coefficients at infinite dilution using GLC. • Sixty one organic solvents in the ionic liquid 1-butyl-1-methylmorpholinium tricyanomethanide. • High selectivity for heptane/thiophene, or pyridine, or 1-nitropropane. • The excess thermodynamic functions and the gas–liquid partition coefficients were presented. • Possible entrainer for the extraction of sulphur and nitrogen-compounds from alkanes. -- Abstract: The activity coefficients at infinite dilution, γ 13 ∞ , for 61 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, esters, aldehyde, acetonitrile, pyridine and 1-nitropropane in the ionic liquid (IL) 1-butyl-1-methylmorpholinium tricyanomethanide, [BMMOR][TCM] were determined by gas–liquid chromatography at six temperatures within the range of (318.15 to 368.15) K. The thermodynamic functions at infinite dilution as partial molar excess Gibbs free energy ΔG 1 E,∞ , enthalpy ΔH 1 E,∞ , and entropy term T ref ΔS 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The density of [BMMOR][TCM] was measured over the temperature range (288.15 to 368.15) K. The gas–liquid partition coefficient K L was calculated for all solutes. The values of selectivity and capacity for a few separation problems such as hexane/benzene, cyclohexane/benzene, heptane/thiophene at T = 328.15 K were calculated from γ 13 ∞ and compared to literature values for similar ionic liquids, viz. N-methyl-2-pyrrolidinone (NMP), and sulfolane. In comparison with the previously measured values for [BMPYR][TCM], the morpholinium IL presents high selectivity for the separation of aromatic hydrocarbons from aliphatic hydrocarbons, and especially thiophene, or piridine from heptane with a slightly lower capacity. New data show that [BMMOR][TCM] IL may be proposed as an alternative solvent for the separation of

  15. Measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide

    International Nuclear Information System (INIS)

    Domańska, Urszula; Lukoshko, Elena Vadimovna

    2013-01-01

    Highlights: • Measurements of activity coefficients at infinite dilution using GLC. • 62 organic solvents and water in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide. • High capacity for thiophene, 1.37 at T = 328.15 K. • Possible entrainer for extraction of sulfur, or nitrogen compounds from fuels. • The excess thermodynamic functions and the gas–liquid partition coefficients were calculated. -- Abstract: The activity coefficients at infinite dilution, γ 13 ∞ , for 62 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, acetonitrile, pyridine and 1-nitropropane in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide, [BMPYR][TCM] were determined by gas–liquid chromatography at six temperatures over the range of (318.15 to 368.15) K. The partial molar excess Gibbs free energy, ΔG 1 E ∞, enthalpy ΔH 1 E ∞, and entropy term T ref ΔS 1 E ,∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The densities of [BMPYR][TCM] were measured within temperature range from 318.15 K to 368.15 K. The gas–liquid partition coefficients, K L were calculated for all solutes. The values of selectivity for few separation problems as hexane/benzene, cyclohexane/benzene, heptane/thiophene were calculated from γ 13 ∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other ionic liquids based on [BMPYR] + cation. In comparison with the former measured ILs, [BMPYR][TCM] present quite high selectivity for the separation of aromatic hydrocarbons and aliphatics hydrocarbons, an average capacity for benzene. The data presented here shows that [BMPYR][TCM] ionic liquid can be used as an alternative solvent for the separation of thiophene from the aliphatic hydrocarbons

  16. Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide

    International Nuclear Information System (INIS)

    Marciniak, Andrzej; Wlazło, Michał

    2012-01-01

    Highlights: The and KL for 61 solutes in the ionic liquid [COC2mPIP][NTf2] were determined by IGC at different temperatures. ► The partial molar excess Gibbs energies, enthalpies and entropies at infinite dilution were calculated. ► The selectivities for selected compounds which form azeotropic mixtures were calculated and compared to other ILs. ► LFER system constants as a function of temperature for [COC2mPIP][NTf2] were calculated. - Abstract: The activity coefficients at infinite dilution, γ ∞ and gas–liquid partition coefficients, K L for 61 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, butanal, acetonitrile, and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide were determined by inverse gas chromatography at the temperatures from (318.15 to 368.15) K. The partial molar excess Gibbs free energies ΔG 1 E,∞ , enthalpies ΔH 1 E,∞ and entropies ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ ∞ values obtained over the temperature range. The selectivities for selected compounds, which form azeotropic mixtures, were calculated from the γ ∞ and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion.

  17. Measurements of activity coefficients at infinite dilution of aliphatic and aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, MTBE, and water in ionic liquid [BMIM][SCN] using GLC

    International Nuclear Information System (INIS)

    Domanska, Urszula; Laskowska, Marta

    2009-01-01

    The activity coefficients at infinite dilution, γ 13 ∞ for 32 solutes: alkanes, alken-1-es, alkyn-1-es, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, tert-butyl methyl ether, and water in the ionic liquid 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN] were determined by gas-liquid chromatography at the temperatures from 298.15 K to 368.15 K. The values of the partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for the hexane/benzene, cyclohexane/benzene, hexane/thiophene, and other separation problems were calculated from the γ 13 ∞ and compared to the other ionic liquids, N-methyl-2-pyrrolidinone, and sulfolane, taken from the recent literature. This work demonstrates that with chosen ionic liquid it is possible to separate different organic compounds with the highest selectivity, ever published

  18. Measurements of activity coefficients at infinite dilution of aromatic and aliphatic hydrocarbons, alcohols, and water in the new ionic liquid [EMIM][SCN] using GLC

    International Nuclear Information System (INIS)

    Domanska, Urszula; Marciniak, Andrzej

    2008-01-01

    A new ionic liquid was chosen for the separation of aromatic hydrocarbons from aliphatic hydrocarbons. The activity coefficients at infinite dilution, γ 13 ∞ for 29 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, and water in the ionic liquid 1-ethyl-3-methyl-imidazolium thiocyanate [EMIM][SCN] were determined by gas-liquid chromatography at the temperatures from 298.15 K to 368.15 K. The values of the partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for the hexane/benzene and cyclohexane/benzene separation problems were calculated from the γ 13 ∞ and compared to the other ionic liquids, NMP and sulfolane, taken from the recent literature. This work demonstrates that with chosen ionic liquid it is possible to separate different organic compounds with the highest selectivity ever published

  19. Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide

    Energy Technology Data Exchange (ETDEWEB)

    Domanska, Urszula [Physical Chemistry Department, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)], E-mail: ula@ch.pw.edu.pl; Marciniak, Andrzej [Physical Chemistry Department, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

    2009-12-15

    The activity coefficients at infinite dilution, {gamma}{sub 13}{sup {infinity}} for 36 solutes: alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, ethers, acetone, and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide [bmPY][NTf{sub 2}] were determined by gas-liquid chromatography at temperatures from 298.15 K to 368.15 K. The partial molar excess enthalpies at infinite dilution values {delta}H{sub 1}{sup E,{infinity}} were calculated from the experimental {gamma}{sub 13}{sup {infinity}} values obtained over the temperature range. The selectivity for different separation problems were calculated from the {gamma}{sub 13}{sup {infinity}} and compared to the literature values for other ionic liquids, N-methyl-2-pyrrolidinone (NMP) and sulfolane.

  20. Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide

    International Nuclear Information System (INIS)

    Domanska, Urszula; Marciniak, Andrzej

    2009-01-01

    The activity coefficients at infinite dilution, γ 13 ∞ for 36 solutes: alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, ethers, acetone, and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide [bmPY][NTf 2 ] were determined by gas-liquid chromatography at temperatures from 298.15 K to 368.15 K. The partial molar excess enthalpies at infinite dilution values ΔH 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivity for different separation problems were calculated from the γ 13 ∞ and compared to the literature values for other ionic liquids, N-methyl-2-pyrrolidinone (NMP) and sulfolane.

  1. Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate

    International Nuclear Information System (INIS)

    Marciniak, Andrzej; Wlazło, Michał

    2013-01-01

    Highlights: • γ ∞ and K L for 65 solutes in the IL [C 2 OHmim][FAP] were determined by IGC. • Partial molar thermodynamics functions ΔG 1 E,∞ , ΔH 1 E,∞ and ΔS 1 E,∞ were calculated. • Selectivities and capacities for alkanes/thiophene separation problems were calculated. • LFER system constants as a function of T for [C 2 OHmim][FAP] were calculated. • Results were compared to other ILs based on the same cation and anion. -- Abstract: This work presents new data of activity coefficients at infinite dilution, γ ∞ of different organic solutes and water in the 1-(2-hydroxyethyl)-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate, [C 2 OHmim][FAP] ionic liquid. Values of γ ∞ were determined for 65 organic solutes, including alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, aldehydes, acetonitrile and water by inverse gas chromatography within the temperature range from (318.15 to 368.15) K. The basic thermodynamic functions, such as partial molar excess Gibbs energies, ΔG 1 E,∞ , enthalpies, ΔH 1 E,∞ and entropies, ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ ∞ values obtained over the temperature range. Additionally the gas–liquid partition coefficients, K L were determined. Experimental values of gas–liquid partition coefficients were used to determine the coefficients in the Abraham solvation parameter model (LFER). Results are compared to previously investigated ionic liquids with the same [C 2 OHmim] + cation and [FAP] − anion. The selectivity and capacity at infinite dilution for alkanes/thiophene extraction problems were calculated from experimental γ ∞ values to verify the possibility of investigated ionic liquid as an entrainer in liquid–liquid extraction

  2. Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide

    Energy Technology Data Exchange (ETDEWEB)

    Marciniak, Andrzej, E-mail: a.marciniak@ch.pw.edu.pl [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

    2011-10-15

    Highlights: > The {gamma}{sub 13}{sup {infinity}} and KL for 46 solutes in the ionic liquid [N-C3OHPY][NTf2] were determined by GLC at different temperatures. > The partial molar excess Gibbs energies {Delta}G{sub 1}{sup E,{infinity}}, enthalpies {Delta}H{sub 1}{sup E,{infinity}} and entropies {Delta}S{sub 1}{sup E,{infinity}} at infinite dilution were calculated. > The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated and compared to other ILs, NMP and sulfolane. > The selectivities for selected compounds which form azeotropic mixtures were calculated. - Abstract: The activity coefficients at infinite dilution, {gamma}{sub 13}{sup {infinity}} and gas-liquid partition coefficients, K{sub L} for 46 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, acetic acid, and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide were determined by gas-liquid chromatography at the temperatures from (308.15 to 378.15) K. The partial molar excess Gibbs free energies {Delta}G{sub 1}{sup E,{infinity}}, enthalpies {Delta}H{sub 1}{sup E,{infinity}} and entropies {Delta}S{sub 1}{sup E,{infinity}} at infinite dilution were calculated from the experimental {gamma}{sub 13}{sup {infinity}} values obtained over the temperature range. The selectivities for aliphatic/aromatic hydrocarbons separation problem were calculated from the {gamma}{sub 13}{sup {infinity}} and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion, NMP and sulfolane. It was found that the investigated ionic liquid shows much higher selectivity at infinite dilution than the general used organic solvents such as NMP, sulfolane and other ionic liquids. Additionally the selectivities for selected compounds which form azeotropic mixtures were calculated.

  3. Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide

    International Nuclear Information System (INIS)

    Marciniak, Andrzej

    2011-01-01

    Highlights: → The γ 13 ∞ and KL for 46 solutes in the ionic liquid [N-C3OHPY][NTf2] were determined by GLC at different temperatures. → The partial molar excess Gibbs energies ΔG 1 E,∞ , enthalpies ΔH 1 E,∞ and entropies ΔS 1 E,∞ at infinite dilution were calculated. → The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated and compared to other ILs, NMP and sulfolane. → The selectivities for selected compounds which form azeotropic mixtures were calculated. - Abstract: The activity coefficients at infinite dilution, γ 13 ∞ and gas-liquid partition coefficients, K L for 46 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, acetic acid, and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide were determined by gas-liquid chromatography at the temperatures from (308.15 to 378.15) K. The partial molar excess Gibbs free energies ΔG 1 E,∞ , enthalpies ΔH 1 E,∞ and entropies ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for aliphatic/aromatic hydrocarbons separation problem were calculated from the γ 13 ∞ and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion, NMP and sulfolane. It was found that the investigated ionic liquid shows much higher selectivity at infinite dilution than the general used organic solvents such as NMP, sulfolane and other ionic liquids. Additionally the selectivities for selected compounds which form azeotropic mixtures were calculated.

  4. Gas-liquid chromatography measurements of activity coefficients at infinite dilution of various organic solutes and water in tri-iso-butylmethylphosphonium tosylate ionic liquid

    International Nuclear Information System (INIS)

    Domanska, Urszula; Paduszynski, Kamil

    2010-01-01

    Activity coefficients at infinite dilution (γ 13 ∞ ) of 33 different solutes (including alkanes, cycloalkanes, alkenes, alkynes, benzene, alkylbenzenes, water, alcohols, MTBE, thiophene and THF) in the ionic liquid tri-iso-butylmethylphosphonium tosylate have been determined by using the GLC method and have been reported over the temperature range (298.15 to 368.15) K. The partial molar excess enthalpies of mixing at infinite dilution have been determined based on temperature dependence of γ 13 ∞ . Selectivity and capacity at infinite dilution has been also calculated for exemplary separation processes in systems n-hexane/benzene and n-hexane/thiophene, to evaluate if the studied ionic liquid is capable to be a good entrainer for these processes, e.g. in the liquid-liquid extraction. The obtained results are promising however the ionic liquid studied shows a lower selectivity than some of imidazolium-based ionic liquids. To our best knowledge, the results indicate that tri-iso-butylmethylphosphonium tosylate is the best for the separation problem of aliphatic hydrocarbons from aromatic hydrocarbons among all of the studied quaternary phosphonium-based ionic liquids.

  5. Application of a General Computer Algorithm Based on the Group-Additivity Method for the Calculation of Two Molecular Descriptors at Both Ends of Dilution: Liquid Viscosity and Activity Coefficient in Water at Infinite Dilution

    Directory of Open Access Journals (Sweden)

    Rudolf Naef

    2017-12-01

    Full Text Available The application of a commonly used computer algorithm based on the group-additivity method for the calculation of the liquid viscosity coefficient at 293.15 K and the activity coefficient at infinite dilution in water at 298.15 K of organic molecules is presented. The method is based on the complete breakdown of the molecules into their constituting atoms, further subdividing them by their immediate neighborhood. A fast Gauss–Seidel fitting method using experimental data from literature is applied for the calculation of the atom groups’ contributions. Plausibility tests have been carried out on each of the calculations using a ten-fold cross-validation procedure which confirms the excellent predictive quality of the method. The goodness of fit (Q2 and the standard deviation (σ of the cross-validation calculations for the viscosity coefficient, expressed as log(η, was 0.9728 and 0.11, respectively, for 413 test molecules, and for the activity coefficient log(γ∞ the corresponding values were 0.9736 and 0.31, respectively, for 621 test compounds. The present approach has proven its versatility in that it enabled the simultaneous evaluation of the liquid viscosity of normal organic compounds as well as of ionic liquids.

  6. Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 4-(2-methoxyethyl)-4-methylmorpholinium trifluorotris(perfluoroethyl)phosphate

    International Nuclear Information System (INIS)

    Wlazło, Michał; Marciniak, Andrzej

    2012-01-01

    Highlights: ► The γ 13 ∞ and K L for 62 solutes in the IL [COC 2 mMOR][FAP] were determined by IGC. ► Partial molar excess thermodynamic functions at infinite dilution were calculated. ► The selectivities and capacities for selected separation problems were calculated. ► LFER system constants as a function of T for [COC 2 mMOR][FAP] were calculated. - Abstract: This paper presents new data on activity coefficients at infinite dilution, γ ∞ for 62 different solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water in the ionic liquid 4-(2-methoxyethyl)-4-methylmorpholinium trifluorotris(perfluoroethyl)phosphate, [COC 2 mMOR][FAP]. The data were determined by inverse gas chromatography at six temperatures from T = 318.15 K to T = 368.15 K. These values were compared with ionic liquid based on the same cation and bis(trifluoromethylsulfonyl)-amide anion, [COC 2 mMOR][NTf 2 ]. Additionally the partial molar excess Gibbs free energies ΔG 1 E,∞ , enthalpies ΔH 1 E,∞ , and entropies ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ ∞ values obtained over the temperatures range. The selectivities and capacities at infinite dilution for hexane/benzene, cyclohexane/benzene, and heptane/thiophene extraction problems were calculated from the γ ∞ to verify the possibility of investigated ionic liquid as an entrainer in liquid–liquid extraction and desulphurization of fuels. Obtained values were compared with literature data of other ionic liquids based on trifluorotris(perfluoroethyl)phosphate and bis(trifluoromethylsulfonyl)-amide anions and industrial solvents: NMP and sulfolane. Also the Abraham solvation parameter model was used for evaluation of the solvation characteristic of the ionic liquid. Linear free energy relationship (LFER) system constants as a function of temperature were calculated.

  7. Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate using gas-liquid chromatography at T = (313.15, 323.15, and 333.15) K

    International Nuclear Information System (INIS)

    Olivier, Eugene; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

    2010-01-01

    Activity coefficients at infinite dilution were determined for 24 solutes (n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, and alcohols) in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate by gas-liquid chromatography at three different temperatures T = (313.15, 323.15, 333.15) K. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental results over the same temperature range. Selectivities and capacities at infinite dilution for the hexane/benzene and methanol/benzene separation problems were calculated from experimental infinite dilution activity coefficient values. The activity coefficients, enthalpies, selectivities, and capacities are discussed and compared to literature values for other ionic liquids, as well as industrial molecular solvents.

  8. Activity coefficients at infinite dilution for solutes in the trioctylmethylammonium bis(trifluoromethylsulfonyl)imide ionic liquid using gas-liquid chromatography

    International Nuclear Information System (INIS)

    Gwala, Nobuhle V.; Deenadayalu, Nirmala; Tumba, Kaniki; Ramjugernath, Deresh

    2010-01-01

    The activity coefficient at infinite dilution (γ 13 ∞ ) for 30 solutes: alkanes, alkenes, cycloalkanes, alkynes, ketones, alcohols, and aromatic compounds was determined from gas-liquid chromatography (glc) measurements at three temperatures (303.15, 313.15, and 323.15) K. The ionic liquid: trioctylmethylammonium bis(trifluoromethylsulfonyl)imide, was used as the stationary phase. For each temperature, γ 13 ∞ values were determined using two columns with different mass percent packing of the ionic liquid. The selectivity (S 12 ∞ ) value was calculated from the γ 13 ∞ to determine the suitability of the solvent as a potential entrainer for extractive distillation in the separation of an hexane/benzene mixture, indicative of a typical industrial separation problem for benchmarking purposes.

  9. Infinite dilution activity coefficients of volatile organic compounds in two ionic liquids composed of the tris(pentafluoroethyl)trifluorophosphate ([FAP]) anion and a functionalized cation

    International Nuclear Information System (INIS)

    Órfão, Eliana Fernandes; Dohnal, Vladimír; Blahut, Aleš

    2013-01-01

    Highlights: • Limiting activity coefficients and gas–liquid partition coefficients for 30 VOCs were determined by GLC. • Solution thermodynamic quantities were derived and analyzed. • [MO-EMPYR][FAP] and [HO-EMIM][FAP] were identified as ILs of very low and very high cohesivity, respectively. • [HO-EMIM][FAP] is an IL of extreme H-bond acidity exhibiting superior performance for petrochemical separations. • Both studied [FAP] ILs were indicated to separate some azeotropic mixtures of alcohols with aprotic oxygenates. -- Abstract: Interactions of volatile organic compounds with two ionic liquids (ILs) containing tris(pentafluoroethyl)trifluorophosphate ([FAP]) anion and a functionalized cation, 1-(2-hydroxyethyl)-3-methylimidazolium ([HO-EMIM]) and 1-(2-methoxyethyl)-1-methylpyrrolidinium ([MO-EMPYR]), were explored through systematic GLC retention measurements. Infinite dilution activity coefficients γ 1 ∞ and gas–liquid partition coefficients K L of 30 selected solutes in [HO-EMIM][FAP] and [MO-EMPYR][FAP] were determined at five temperatures in the range from (318.15 to 353.15) K. Partial molar excess enthalpies and entropies at infinite dilution were derived from the temperature dependence of the γ 1 ∞ values. The Linear Free Energy Relationship (LFER) solvation model was used to correlate the K L values. The LFER correlation parameters and excess thermodynamic functions were analyzed to identify molecular interactions operating between the ILs and the individual solutes. By comparing the behaviors of the studied ILs and of their closely similar unfunctionalized analogs, net effects imparted by cation functionalization were also disclosed. The cohesivity of the two ILs was shown to differ dramatically: while [MO-EMPYR][FAP] ranks among ILs to the least cohesive, [HO-EMIM][FAP] belongs to the most cohesive ones. Both [HO-EMIM][FAP] and [MO-EMPYR][FAP] are capable of interacting with solutes specifically through dipolarity/polarizibility and

  10. Activity coefficients at infinite dilution of organic solutes in the ionic liquid trihexyltetradecylphosphonium bis (trifluoromethylsulfonyl) imide using gas–liquid chromatography at T = (313.15, 333.15, 353.15 and 373.15) K

    International Nuclear Information System (INIS)

    Tumba, Kaniki; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

    2013-01-01

    Highlights: • Activity coefficients at infinite dilution measured in the ionic liquid [3C 6 C 14 P][BTI]. • 22 solutes investigated at T = (313.15, 333.15, 353.15, 373.15) K using glc. • Selectivities and capacities for selected separations compared to other IL’s and solvents. -- Abstract: Activity coefficients at infinite dilution for organic solutes, which include n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, alcohols and ketones, in the ionic liquid trihexyltetradecylphosphonium bis (trifluoromethylsulfonyl) imide were measured by gas–liquid chromatography using the latter as the stationary phase. This ionic liquid had previously been studied and reported in literature; however due to significant discrepancies in the reported infinite activity coefficient values, there was justification for further study and reporting. The temperature range investigated in this study is significantly wider and at higher temperatures than presented previously in the literature. From the experimental infinite dilution activity coefficient data at the four different temperatures T = (313.15, 333.15, 353.15 and 373.15) K, partial molar excess enthalpies at infinite dilution were calculated. Values of the selectivity for hexane/benzene and methanol/benzene separations were determined from experimental values of the activity coefficients at infinite dilution and these results were compared to literature values for other ionic liquids, as well as for industrial solvents. The capacities were also determined as it gives an indication of the solvent extraction behavior of the ionic liquid

  11. Determination of infinite dilution activity coefficients using HS-SPME/GC/FID for hydrocarbons in furfural at temperatures of (298.15, 308.15, and 318.15) K

    International Nuclear Information System (INIS)

    Arantes Furtado, Filipe; Vieira Coelho, Gerson Luiz

    2012-01-01

    Highlights: ► Two approaches were proposed using SPME on determination of infinite dilution activity coefficients. ► Infinite dilution activity coefficients of nine solutes in solvent furfural at T = (298.15, 308.15, and 318.15) K. ► Fiber–gas partition coefficients of nine solutes on PDMS at T = (298.15, 308.15, and 318.15) K. ► Optical microscopy analysis and statistical tests to measure possible damages on fiber coating. ► Advantages and limitations of methodology proposed were discussed. - Abstract: A new methodology using the headspace solid phase microextraction (HS-SPME) technique has been used to evaluate the infinite dilution activity coefficient (γ 12 ∞ ) of nine hydrocarbons (alkanes, cycloalkanes, and aromatics) in furfural solvent. The main objective of this study was to validate a faster and lower cost methodology expanding the use of HS-SPME to determine infinite dilution activity of solutes in organic solvents. Two approaches were proposed for the determination of γ 12 ∞ in order to use this technique (HS-SPME). In addition, the fiber–gas partition coefficients (K fg ) for each analyte at each of the studied temperatures were determined. The activity and partition coefficients have been reported at temperatures of (298.15, 308.15, and 318.15) K. The data were compared with the literature infinite dilution data determined by other methods such as liquid–gas chromatography (GLC) and gas stripping. Partial molar excess enthalpies of mixing at infinite dilution for each solute have been determined. The fibers were tested before and after each experiment, using statistical methods to ensure that their properties do not change during the experiments. The fibers were also analyzed by optical microscopy to evaluate possible surface damage by comparing them with new fibers. The activity coefficient values correlated well with the data in the literature and showed average deviations less than 10%.

  12. Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate using gas-liquid chromatography at T = (313.15, 323.15, and 333.15) K

    International Nuclear Information System (INIS)

    Olivier, Eugene; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

    2010-01-01

    Activity coefficients at infinite dilution were determined for 24 solutes: n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes and alcohols in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate, [OMIM][PF 6 ], by gas-liquid chromatography at three different temperatures T = (313.15, 323.15, and 333.15) K. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental data over the same temperature range. Capacities and selectivities at infinite dilution for the systems hexane/benzene and methanol/benzene were determined from the experimental data and compared to the literature values for other ionic liquids, as well as for industrial molecular solvents. The influence of the cation and anion of the ionic liquid on the activity coefficient is discussed, as well as the usefulness of [OMIM][PF 6 ] in separating organic liquids.

  13. Activity coefficients at infinite dilution of organic solutes in N-alkylpyridinium bis(trifluoromethylsulfonyl)imide ([CnPY][NTf2], n = 2, 4, 5) using gas-liquid chromatography

    International Nuclear Information System (INIS)

    Yan Peifang; Liu Qingshan; Yang Miao; Liu Xiumei; Tan Zhicheng; Welz-Biermann, Urs

    2010-01-01

    The activity coefficients at infinite dilution, γ i ∞ for both polar and non-polar solutes in the ionic liquids N-alkylpyridinium bis(trifluoromethylsulfonyl)imide ([C n PY][NTf 2 ], n = 2, 4, 5) have been determined by gas-liquid chromatography using the ionic liquid as the stationary phase. The measurements were carried out at the temperatures from (303 to 353) K. The partial molar excess enthalpies at infinite dilution H i E,∞ of the solutes in the ionic liquids were also derived from the temperature dependence of the γ i ∞ values. The values of the selectivity for the hexane/benzene and cyclohexane/benzene separation problems were calculated from experimental infinite dilution activity coefficient values and compared to the other ionic liquids, taken from the recent literatures.

  14. Time correlation functions and transport coefficients in a dilute superfluid

    International Nuclear Information System (INIS)

    Kirkpatrick, T.R.; Dorfman, J.R.

    1985-01-01

    Time correlation functions for the transport coefficients in the linear Landau-Khalatnikov equations are derived on the basis of a formal theory. These Green--Kubo expressions are then explicitly evaluated for a dilute superfluid and the resulting transport coefficiencts are shown to be identical to those obtained previously by using a distribution function method

  15. Activity coefficients at infinite dilution of organic solutes in the ionic liquid trihexyl(tetradecyl)phosphonium tetrafluoroborate using gas-liquid chromatography at T = (313.15, 333.15, 353.15, and 373.15) K

    International Nuclear Information System (INIS)

    Tumba, Kaniki; Reddy, Prashant; Naidoo, Paramespri; Ramjugernath, Deresh

    2011-01-01

    Research highlights: → Activity coefficients at infinite dilution in the ionic liquid [3C 6 C 14 P][BF 4 ]. → Twenty-seven solutes investigated at T = (313.15, 333.15, 353.15, and 373.15) K. → [3C 6 C 14 P][BF 4 ] shows promise for the separation of aromatic and alcohol mixtures. - Abstract: Activity coefficients at infinite dilution have been measured by gas-liquid chromatography for 27 organic solutes (n-alkanes, 1-alkenes, 1-alkynes, cycloalkanes, aromatics, alcohols, and ketones) in the ionic liquid trihexyl(tetradecyl)phosphonium tetrafluoroborate [3C 6 C 14 P][BF 4 ]. The measurements were carried out at four different temperatures viz.T = (313.15, 333.15, 353.15, and 373.15) K. From the experimental data, partial molar excess enthalpy values at infinite dilution were calculated for the experimental temperature range. The selectivity values for the separation of n-hexane/benzene, cyclohexane/benzene, and methanol/benzene mixtures were determined from the experimental infinite dilution activity coefficient values. These values were compared to those available in the literature for other ionic liquids and commercial solvents, so as to assess the feasibility of employing [3C 6 C 14 P][BF 4 ] in solvent-enhanced industrial separations.

  16. Measurements of mass-fraction activity coefficient at infinite dilution of aliphatic and aromatic hydrocarbons, thiophene, alcohols, water, ethers, and ketones in hyperbranched polymer, Boltorn H2004, using inverse gas chromatography

    International Nuclear Information System (INIS)

    Domanska, Urszula; Zolek-Tryznowska, Zuzanna

    2010-01-01

    Thermodynamic properties of the hyperbranched polymer, Boltorn H2004 (B-H2004), were investigated by inverse gas chromatography with 42 different solvents: n-alkanes (C 5 -C 10 ), cycloalkanes (C 5 -C 8 ), alkenes (C 5 -C 8 ), alkynes (C 5 -C 8 ), aromatic hydrocarbons (benzene, toluene, ethylbenzene, o-, m-, p-xylene, thiophene), alcohols (C 1 -C 5 ), water, ethers (tetrahydrofuran (THF), methyl-tert-butylether (MTBE), diethyl-, di-n-propyl-, di-n-butyl ether), and ketones (acetone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, cyclopentanone) at the temperatures from (308.15 to 348.15) K using the inverse gas chromatography (IGC). The density and thermophysical properties of polymer were described. The specific retention volume (V g ), the mass-fraction activity coefficient at infinite dilution (Ω 13 ∞ ), the Flory-Huggins interaction parameter (χ 13 ∞ ), the molar enthalpy of sorption in the polymer (Δ s H), the partial molar excess enthalpy at infinite dilution (ΔH 1 E,∞ ), the molar enthalpy of vaporization to the ideal-gas state for the pure solutes (Δ vap H 0 ), the partial molar Gibbs excess energy at infinite dilution (ΔG 1 E,∞ ), and the solubility parameter of the polymer (δ 3 ), were calculated. The UNIFAC-FV model was used to predict the mass-fraction activity coefficient at infinite dilution for different solutes in the B-H2004 polymer.

  17. Determination of activity coefficients at infinite dilution of water and organic solutes (polar and non-polar) in the Ammoeng 100 ionic liquid at T = (308.15, 313.5, 323.15, and 333.15) K

    International Nuclear Information System (INIS)

    Reddy, Prashant; Chiyen, Kaleng J.; Deenadayalu, Nirmala; Ramjugernath, Deresh

    2011-01-01

    Highlights: → Activity coefficients at infinite dilution in the ionic liquid Ammoeng 100. → Twenty-seven solutes investigated at T = (308.15, 313.15, 323.15, and 333.15) K. → Ammoeng 100 not suited to aromatic/aliphatic and alkane/alcohol separations. - Abstract: Activity coefficients at infinite dilution (γ 13 ∞ ) have been determined for 27 solutes, viz. water and organic compounds (n-alkanes, cycloalkanes, 1-alkenes, 1-alkynes, aromatics, alcohols, and ketones) in the ionic liquid Ammoeng 100, by gas-liquid chromatography at four different temperatures, T = (308.15, 313.15, 323.15, and 333.15) K. Columns with different phase loadings (20 to 24)% of the ionic liquid in the stationary phase were employed to obtain γ 13 ∞ values at each temperature investigated. Partial molar excess enthalpies at infinite dilution (ΔH 1 E,∞ ) were calculated for the solutes from the temperature dependency relationship of the ln(γ 13 ∞ ) values for the temperature range in this study. The uncertainties in the determinations of the γ 13 ∞ and ΔH 1 E,∞ values are 6% and 10%, respectively. Selectivity values at infinite dilution (S ij ∞ ), have been computed from the γ 13 ∞ values to assess the potential candidacy of the Ammoeng 100 ionic liquid for the separation of alkane/alcohol mixtures. The results from this study have been compared to those available for several ionic liquids from previous investigations.

  18. Solute activity coefficients in dilute aqueous electrolyte mixutes. III. The ternary system HCLO4 + UO2(CLO4)2 + H2O at 250C

    International Nuclear Information System (INIS)

    Boyd, G.E.

    1977-01-01

    Isopiestic vapor pressure comparison measurements were conducted with the three-component system HClO 4 + UO 2 (ClO 4 ) 2 + H 2 O in the concentration range between I = 0.05 and 1.9 m. Analysis of the mixture composition and concentration dependence of the osmotic coefficients with the Scatchard neutral-electrolyte and ion-component methods and with the Pitzer ion-component methods gave equally satisfactory results. Prediction of the observed osmotic coefficients by two-component approximations was satisfactory, and the data agreed well with values estimated with a model based on the osmolal fraction. A fair concordance was also found between predicted solute activity coefficients from simple models and values derived from complete treatments which included interaction terms

  19. Activity coefficients at infinite dilution of organic solutes in the ionic liquid, methyl(trioctyl)ammonium thiosalicylate, [N1888][TS] by gas-liquid chromatography at T = (303.15, 313.15, and 323.15) K

    International Nuclear Information System (INIS)

    Reddy, Prashant; Gwala, Nobuhle V.; Deenadayalu, Nirmala; Ramjugernath, Deresh

    2011-01-01

    Research highlights: → Ammonium ionic liquid selectivity value lower than for imidazolium ionic liquid. → Ammonium ionic liquids with smaller alkyl groups have higher selectivity values. → For the same cation the [TS] anion has a higher selectivity than the [NTf 2 ]. - Abstract: In this work, activity coefficients at infinite dilution (γ 13 ∞ ) have been obtained for 19 polar and non-polar organic solutes in the form of n-alkanes, cycloalkanes, 1-alkenes, 1-alkynes, aromatic compounds, and ketones in the ionic liquid methyl(trioctyl)ammonium thiosalicylate by gas-liquid chromatography at three different temperatures, i.e. T = (303.15, 313.15, and 323.15) K. Two columns with different phase loadings of the ionic liquid in the stationary phase (25% and 30%) were employed to obtain γ 13 ∞ values at each temperature investigated. Partial molar excess enthalpies at infinite dilution (ΔH 1 E,∞ ) were calculated for each of the solutes from the temperature dependency of the γ 13 ∞ values for the temperature range in this study. Selectivity values at infinite dilution (S ij ∞ ) were computed from the γ 13 ∞ values to screen the potential candidacy of the ionic liquid for the separation of n-hexane/benzene mixtures. The results from this study have been compared to those available for several other classes of ionic liquids and commercial solvents employed in solvent-enhanced industrial separation processes.

  20. Henry's law constants and infinite dilution activity coefficients of cis-2-butene, dimethylether, chloroethane, and 1,1-difluoroethane in methanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-methyl-2-butanol

    International Nuclear Information System (INIS)

    Miyano, Yoshimori; Kobashi, Takahiro; Shinjo, Hiroshi; Kumada, Shinya; Watanabe, Yusuke; Niya, Wataru; Tateishi, Yoko

    2006-01-01

    Henry's law constants and infinite dilution activity coefficients of cis-2-butene, dimethylether, chloroethane, and 1,1-difluoroethane in methanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-methyl-2-butanol in the temperature range of 250 K to 330 K were measured by a gas stripping method and partial molar excess enthalpies were calculated from the activity coefficients. A rigorous formula for evaluating the Henry's law constants from the gas stripping measurements was used for the data reduction of these highly volatile mixtures. The uncertainty is about 2% for the Henry's law constants and 3% for the estimated infinite dilution activity coefficients. In the evaluation of the infinite dilution activity coefficients, the nonideality of the solute such as the fugacity coefficient and Poynting correction factor cannot be neglected, especially at higher temperatures. The estimated uncertainty of the infinite dilution activity coefficients includes 1% for nonideality

  1. Diffusion coefficients of alloying elements in dilute Mg alloys: A comprehensive first-principles study

    International Nuclear Information System (INIS)

    Zhou, Bi-Cheng; Shang, Shun-Li; Wang, Yi; Liu, Zi-Kui

    2016-01-01

    First-principles calculations based on density functional theory have been used to calculate the temperature-dependent dilute tracer diffusion coefficients for 47 substitutional alloying elements in hexagonal closed packed (hcp) Mg by combining transition state theory and an 8-frequency model. The minimum energy pathways and the saddle point configurations during solute migration are calculated with the climbing image nudged elastic band method. Vibrational properties are obtained using the quasi-harmonic Debye model with inputs from first-principles calculations. An improved generalized gradient approximation of PBEsol is used in the present first-principles calculations, which is able to well describe both vacancy formation energies and vibrational properties. It is found that the solute diffusion coefficients in hcp Mg are roughly inversely proportional to the bulk modulus of the dilute alloys, which reflects the solutes' bonding to Mg. Transition metal elements with d electrons show strong interactions with Mg and have large diffusion activation energies. Correlation effects are not negligible for solutes Ca, Na, Sr, Se, Te, and Y, in which the direct solute migration barriers are much smaller than the solvent (Mg) migration barriers. Calculated diffusion coefficients are in remarkable agreement with available experimental data in the literature.

  2. Activity coefficients at infinite dilution of organic solutes in the ionic liquid PEG-5 cocomonium methylsulfate at T = (313.15, 323.15, 333.15, and 343.15) K: Experimental results and COSMO-RS predictions

    International Nuclear Information System (INIS)

    Reddy, Prashant; Aslam Siddiqi, M.; Atakan, Burak; Diedenhofen, Michael; Ramjugernath, Deresh

    2013-01-01

    Highlights: ► γ 13 ∞ values reported for 25 organic solutes in the ionic liquid PEG-5 cocomonium methylsulfate. ► Measurements undertaken using the g.l.c. technique at T = (313.15, 323.15, 333.15, and 343.15) K. ► Sound speed, density and refractive index data for ionic liquid PEG-5 cocomonium methylsulfate also reported. ► Measured γ 13 ∞ values compared to COSMO-RS predictions. -- Abstract: Activity coefficients at infinite dilution γ 13 ∞ have been determined for 25 polar and non-polar organic solutes (alkanes, cycloalkanes, alk-1-enes, alk-1-ynes, aromatic compounds, alcohols, and ketones) in the ionic liquid PEG-5 cocomonium methylsulfate with gas–liquid chromatography at four different temperatures, T = (313.15, 323.15, 333.15, and 343.15) K. Packed columns with phase loadings of 0.28 and 0.34 ionic liquid mass fraction in the stationary phase were employed to obtain γ 13 ∞ values at each temperature investigated. Speed of sound, density, and refractive index values have also been measured for the pure ionic liquid at P = 0.1 MPa and T = (303.15, 313.15, 323.15, 333.15, and 343.15) K. The uncertainties in the sound speeds, densities, and refractive indices are estimated to be values of 0.9 m · s −1 , 0.00003 g · cm −3 , and 0.00002, respectively. Partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated for the solutes from the temperature dependency of the γ 13 ∞ values for the temperature range of this study. The uncertainties in the determinations of γ 13 ∞ and ΔH 1 E,∞ values are 5% and 10%, respectively. Selectivity values at infinite dilution S 12 ∞ for hexane/benzene, cyclohexane/benzene, hexane/hex-1-ene, and hexane/ethanol separations have been calculated. These have been compared against values obtained from COSMO-RS predictions

  3. Determination of diffusion coefficients of various livestock antibiotics in water at infinite dilution

    Directory of Open Access Journals (Sweden)

    Soriano Allan N.

    2017-01-01

    Full Text Available The fate of antibiotics entering the environment raised concerns on the possible effect of antimicrobial resistance bacteria. Prediction of the fate and transport of these particles are needed to be determined, significantly the diffusion coefficient of antibiotic in water at infinite dilution. A systematic determination of diffusion coefficient of antibiotic in water at infinite dilution of five different kinds of livestock antibiotics namely: Amtyl, Ciprotyl, Doxylak Forte, Trisullak, and Vetracin Gold in the 293.15 to 313.15 K temperature range are reported through the use of the method involving the electrolytic conductivity measurements. A continuous stirred tank reactor is utilized to measure the electrolytic conductivities of the considered systems. These conductivities are correlated by using the Nernst-Haskell equation to determine the infinite dilution diffusion coefficient. Determined diffusion coefficients are based on the assumption that in dilute solution, these antibiotics behave as strong electrolyte from which H+ cation dissociate from the antibiotic’s anion.

  4. Determination of diffusion coefficients of various livestock antibiotics in water at infinite dilution

    Science.gov (United States)

    Soriano, Allan N.; Adamos, Kristoni G.; Bonifacio, Pauline B.; Adornado, Adonis P.; Bungay, Vergel C.; Vairavan, Rajendaran

    2017-11-01

    The fate of antibiotics entering the environment raised concerns on the possible effect of antimicrobial resistance bacteria. Prediction of the fate and transport of these particles are needed to be determined, significantly the diffusion coefficient of antibiotic in water at infinite dilution. A systematic determination of diffusion coefficient of antibiotic in water at infinite dilution of five different kinds of livestock antibiotics namely: Amtyl, Ciprotyl, Doxylak Forte, Trisullak, and Vetracin Gold in the 293.15 to 313.15 K temperature range are reported through the use of the method involving the electrolytic conductivity measurements. A continuous stirred tank reactor is utilized to measure the electrolytic conductivities of the considered systems. These conductivities are correlated by using the Nernst-Haskell equation to determine the infinite dilution diffusion coefficient. Determined diffusion coefficients are based on the assumption that in dilute solution, these antibiotics behave as strong electrolyte from which H+ cation dissociate from the antibiotic's anion.

  5. Activity coefficients of solutes in binary solvents

    International Nuclear Information System (INIS)

    Gokcen, N.A.

    1982-01-01

    The activity coefficients in dilute ternary systems are discussed in detail by using the Margules equations. Analyses of some relevant data at high temperatures show that the sparingly dissolved solutes in binary solvents follow complex behavior even when the binary solvents are very nearly ideal. It is shown that the activity data on the solute or the binary system cannot permit computation of the remaining activities except for the regular solutions. It is also shown that a fourth-order equation is usually adequate in expressing the activity coefficient of a solute in binary solvents at high temperatures. When the activity data for a binary solvent are difficult to obtain in a certain range of composition, the activity data for a sparingly dissolved solute can be used to supplement determination of the binary activities

  6. Measurement of Henry’s Law constant and infinite dilution activity coefficient of isopropyl mercaptan and isobutyl mercaptan in (methyldiethanolamine (1) + water (2)) with w_1 = 0.25 and 0.50 at temperature of (298 to 348) K using inert gas stripping method

    International Nuclear Information System (INIS)

    Zin, Rohani Mohd; Coquelet, Christophe; Valtz, Alain; Abdul Mutalib, Mohamed I.; Sabil, Khalik Mohamad

    2016-01-01

    Highlights: • Measurement of Henry’s Law constants of nPM, iPM, nBM and iBM in aqueous MDEA. • Measurement of infinite dilution activity coefficients of nPM, iPM, nBM and iBM in aqueous MDEA. • Measurement using gas stripping method for T = (298 to 348) K and MDEA solution of (25 and 50) wt%. • Limiting activity coefficient and Henry’s Law constant is increasing with solute molecular size. • The experimental technique has provided information about heats of solution of aqueous MDEA. - Abstract: In this study, the Henry’s Law constant and the activity coefficients in infinite dilution in a mass fraction of (25 and 50)% of methyldiethanolamine (MDEA) aqueous solution within the temperature range of (298 to 348) K at atmospheric pressure, were measured. An inert gas stripping method was used to perform all the measurements. The new values of Henry’s Law constant and the activity coefficients in infinite dilution correlation with solute molecular size were explained. The influence of the solvent is discussed taking into consideration the heat of absorptions for different MDEA concentrations. Experimental results are compared to literature data wherever available.

  7. On the second-order temperature jump coefficient of a dilute gas

    Science.gov (United States)

    Radtke, Gregg A.; Hadjiconstantinou, N. G.; Takata, S.; Aoki, K.

    2012-09-01

    We use LVDSMC simulations to calculate the second-order temperature jump coefficient for a dilute gas whose temperature is governed by the Poisson equation with a constant forcing term. Both the hard sphere gas and the BGK model of the Boltzmann equation are considered. Our results show that the temperature jump coefficient is different from the well known linear and steady case where the temperature is governed by the homogeneous heat conduction (Laplace) equation.

  8. Activity coefficients at infinite dilution measurements for organic solutes in the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide using g.l.c. at T=(298.15, 313.15, and 333.15) K

    International Nuclear Information System (INIS)

    Letcher, Trevor M.; Marciniak, Andrzej; Marciniak, MaIgorzata; Domanska, Urszula

    2005-01-01

    The activity coefficients at infinite dilution, γ 13 ∞ (where 1 refers to the solute and 3 to the solvent), for both polar and non-polar solutes (alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, benzene, carbon tetrachloride, and methanol) in the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide [HMIM][Tf 2 N] at three temperatures T=(298.15, 313.15, and 333.15) K have been determined by gas-liquid chromatography. The interaction at the gas-liquid interface between the solutes and the solvent was examined by varying solvent liquid loading on the column. Corrected retention values, taking carrier gas and solute imperfections into account, were determined and used to calculate the activity coefficients at infinite dilution. The results have been used to predict the solvent potential for the hexane/benzene separation from calculated selectivity values. The results were compared to γ 13 ∞ for similar systems found in the literature in an attempt to understand the effect of the nature of the cation and anion has on solute-solvent interactions. The partial molar excess enthalpies at infinite dilution values ΔH 1 E∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range

  9. Measurement of activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate at T = (308.15, 313.15, 323.15 and 333.15) K using gas + liquid chromatography

    International Nuclear Information System (INIS)

    Bahadur, Indra; Govender, Byron Bradley; Osman, Khalid; Williams-Wynn, Mark D.; Nelson, Wayne Michael; Naidoo, Paramespri; Ramjugernath, Deresh

    2014-01-01

    Highlights: • Activity coefficients at infinite dilution measured in the ionic liquid [EMIM] + [MDEGSO 4 ] − . • 28 organic solutes investigated at T = (308.15, 313.15, 323.15 and 333.15) K using glc. • Selectivities for selected hexane/benzene separations compared to other IL’s and solvents. • IL shows higher selectivities than conventional solvents such as NMP, NFM, and sulfolane. -- Abstract: In this study, the interactions between volatile organic compounds and the ionic liquid (IL) 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate [EMIM] + [MDEGSO 4 ] − were investigated using gas + liquid chromatography measurements. The activity coefficients at infinite dilution γ 13 ∞ were determined for 28 polar and non-polar organic solutes (alkanes, cycloalkanes, alkenes, alkynes, aromatic compounds, alcohols, and ketones) in 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate at T = (308.15, 313.15, 323.15 and 333.15) K. Packed columns with phase loadings of 0.27 and 0.37 mass fraction of the IL in the stationary phase were employed to obtain γ 13 ∞ values at each temperature. Density and refractive index values were also measured for the pure IL at P = 0.1 MPa and at the experimental temperatures. Partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated for the solutes from the temperature dependency of the γ 13 ∞ values. The uncertainties in the activity coefficient at infinite dilution were critically evaluated and estimated on average to be ±5.3%. Selectivity values at infinite dilution S ij ∞ for the hexane/benzene separation were also calculated at T = 308.15 K. The selectivity S ij ∞ value of the IL investigated in this study is approximately 3.7 times greater than that for NMP, 2.6 times greater than that for NFM, and 2.3 times greater than that for sulfolane. These results indicate the potential use of this IL in extractive separation processes

  10. Determinação do coeficiente de atividade na diluição infinita (g¥ através da micro-extração em fase sólida (SPME Determination of activity coefficients at infinite dilution through solid phase microextraction (SPME

    Directory of Open Access Journals (Sweden)

    Douglas B. Fonseca

    2007-01-01

    Full Text Available In this study a new approach, solid phase micro extraction (SPME, is used in the evaluation of the infinite dilution activity coefficient of the solute in a given solvent. It is the purpose of the current work to demonstrate a different approach to obtain the data needed for studying the solution thermodynamics of binary liquid mixtures as well as for designing multi-component separations. The solutes investigated at the temperature 298.15 K were toluene, ethyl benzene and xylene in the solvent methanol.

  11. Activity coefficients of electrons and holes in semiconductors

    International Nuclear Information System (INIS)

    Orazem, M.E.; Newman, J.

    1984-01-01

    Dilute-solution transport equations with constant activity coefficients are commonly used to model semiconductors. These equations are consistent with a Boltzmann distribution and are invalid in regions where the species concentration is close to the respective site concentration. A more rigorous treatment of transport in a semiconductor requires activity coefficients which are functions of concentration. Expressions are presented for activity coefficients of electrons and holes in semiconductors for which conduction- and valence-band energy levels are given by the respective bandedge energy levels. These activity coefficients are functions of concentration and are thermodynamically consistent. The use of activity coefficients in macroscopic transport relationships allows a description of electron transport in a manner consistent with the Fermi-Dirac distribution

  12. First-principles calculations of impurity diffusion coefficients in dilute Mg alloys using the 8-frequency model

    International Nuclear Information System (INIS)

    Ganeshan, S.; Hector, L.G.; Liu, Z.-K.

    2011-01-01

    Research highlights: → Implemented the eight frequency model for impurity diffusion in hexagonal metals. → Model inputs were energetics/vibrational properties from first princples. → Predicted diffusion coefficients for Al, Ca, Zn and Sn impurity diffusion in Mg. → Successful prediction of partial correlation factors and jump frequencies. → Good agreement between calculated and experimental results. - Abstract: Diffusion in dilute Mg-X alloys, where X denotes Al, Zn, Sn and Ca impurities, was investigated with first-principles density functional theory in the local density approximation. Impurity diffusion coefficients were computed as a function of temperature using the 8-frequency model which provided the relevant impurity and solvent (Mg) jump frequencies and correlation factors. Minimum energy pathways for impurity diffusion and associated saddle point structures were computed with the climbing image nudged elastic band method. Vibrational properties were obtained with the supercell (direct) method for lattice dynamics. Calculated diffusion coefficients were compared with available experimental data. For diffusion between basal planes, we find D Mg-Ca > D Mg-Zn > D Mg-Sn > D Mg-Al, where D is the diffusion coefficient. For diffusion within a basal plane, the same trend holds except that D Mg-Zn overlaps with D Mg-Al at high temperatures and D Mg-Sn at low temperatures. These trends were explored with charge density contours in selected planes of each Mg-X alloy, the variation of the activation energy for diffusion with the atomic radius of each impurity and the electronic density of states. The theoretical methodology developed herein can be applied to impurity diffusion in other hexagonal materials.

  13. Influence Of Dilution Factor For Activity Measurement Of 60CO

    International Nuclear Information System (INIS)

    Hermawan-Candra; Nazaroh; Ermi-Juita

    2003-01-01

    Influence of dilution factor for activity measurement of 60 Co has been studied. The aim of this research is to determine influence between activity measurement result of 60 Co before and after diluted. Measurement were done by using ionization chamber detectors system and gamma spectrometry system with NaI(TI) detector. Discrepancy within three ionization chambers measurements were 0.2% - 2.1% and NaI(Tl) were 3.5% - 6%. (author)

  14. Activity risk coefficients for living generations

    International Nuclear Information System (INIS)

    Raicevic, J.; Merkle, M.; Ninkovic, M. M.

    1993-01-01

    This paper deals with the new concept of the Activity risk coefficients, ARCs, which are in Probabilistic risk assessment PRA computer codes used for the calculation of the stochastic effects due to low dose exposures. As an example, ARC expressions for the Cloudshine is derived. (author)

  15. THERMODYNAMICS OF ELECTROLYTES. X. ENTHALPY AND THE EFFECT OF TEMPERATURE ON THE ACTIVITY COEFFICIENTS.

    Energy Technology Data Exchange (ETDEWEB)

    Silvester, Leonard F.; Pitzer, Kenneth S.

    1977-11-01

    Heat of dilution and of solution data are fitted to the form of equation corresponding to that used successfully for activity and osmotic coefficients over a wide range of concentration. The resulting parameters give the change with temperature of the activity and osmotic coefficients. Results are reported for 84 electrolytes of 1-1, 2-1, 3-1, and 2-2 valence types.

  16. Activity coefficient of aqueous sodium bicarbonate

    Energy Technology Data Exchange (ETDEWEB)

    Pitzer, Kenneth S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Peiper, J. Christopher [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

    1980-09-01

    The determination of the activity coefficient and related properties of sodium bicarbonate presents special problems because of the appreciable vapor pressure of CO2 above such solutions. With the development of reliable equations for the thermodynamic properties of mixed electrolytes, it is possible to determine the parameters for NaHCO3 from cell measurements or NaCl-NaHCO3 mixtures. Literature data are analyzed to illustrate the method and provide interim values, hoever it is noted that further measurements over a wider range of concentrations would yield more definitive results. Lastly, an estimate is also given for the activity coefficient of KHCO3.

  17. Disposal of Low-Activity Liquid Effluents by Dilution

    Energy Technology Data Exchange (ETDEWEB)

    Bovard, P.; Candillon, C. [Atomic Energy Commission, Saclay (France)

    1960-07-01

    Nuclear centres are frequently faced with problems of disposal of sizeable quantities of low-activity liquid effluents. Under present conditions the most practicable solution seems to be to discharge them into a natural or artificial water system, so as to dilute them as much as possible and thus reduce their radioactive isotope content below the public health levels. This technique is employed by all nuclear centres in France, which use the following convenient outlets: Saclay: the artificial ponds made by Louis XIV to feed the great Versailles fountains; Fontenay-aux-Roses: the Paris sewer system; Grenoble: the river Isere; Marcoule: the river Rhone. Until 1957 the amount of waste was negligible. It is still very slight at the first three centres, only a few dozen millicuries a month. At Marcoule the activity of the effluents is somewhat greater, but the Rhone's rate of flow ensures a very low final content of radioactive elements. The increasing discharge of wastes into river systems calls for a close watch on changes in radioactivity in the environment (i.e. in air, water and soil), and especially on areas in which radioactive isotopes may accumulate. We have therefore made laboratory studies of the mechanics of radioactivity concentration, in order to improve our sampling methods and ascertain the movement of wastes.

  18. Comparison of activity coefficient models for electrolyte systems

    DEFF Research Database (Denmark)

    Lin, Yi; ten Kate, Antoon; Mooijer, Miranda

    2010-01-01

    Three activity coefficient models for electrolyte solutions were evaluated and compared. The activity coefficient models are: The electrolyte NRTL model (ElecNRTL) by Aspentech, the mixed solvent electrolyte model (MSE) by OLI Systems Inc., and the Extended UNIQUAC model from the Technical Univer...

  19. Activity coefficients from molecular simulations using the OPAS method

    Science.gov (United States)

    Kohns, Maximilian; Horsch, Martin; Hasse, Hans

    2017-10-01

    A method for determining activity coefficients by molecular dynamics simulations is presented. It is an extension of the OPAS (osmotic pressure for the activity of the solvent) method in previous work for studying the solvent activity in electrolyte solutions. That method is extended here to study activities of all components in mixtures of molecular species. As an example, activity coefficients in liquid mixtures of water and methanol are calculated for 298.15 K and 323.15 K at 1 bar using molecular models from the literature. These dense and strongly interacting mixtures pose a significant challenge to existing methods for determining activity coefficients by molecular simulation. It is shown that the new method yields accurate results for the activity coefficients which are in agreement with results obtained with a thermodynamic integration technique. As the partial molar volumes are needed in the proposed method, the molar excess volume of the system water + methanol is also investigated.

  20. Experimental study of overall heat transfer coefficient in the application of dilute nanofluids in the car radiator

    International Nuclear Information System (INIS)

    Peyghambarzadeh, S.M.; Hashemabadi, S.H.; Naraki, M.; Vermahmoudi, Y.

    2013-01-01

    Heat transfer of coolant flow through the automobile radiators is of great importance for the optimization of fuel consumption. In this study, the heat transfer performance of the automobile radiator is evaluated experimentally by calculating the overall heat transfer coefficient (U) according to the conventional ε-NTU technique. Copper oxide (CuO) and Iron oxide (Fe 2 O 3 ) nanoparticles are added to the water at three concentrations 0.15, 0.4, and 0.65 vol.% with considering the best pH for longer stability. In these experiments, the liquid side Reynolds number is varied in the range of 50–1000 and the inlet liquid to the radiator has a constant temperature which is changed at 50, 65 and 80 °C. The ambient air for cooling of the hot liquid is used at constant temperature and the air Reynolds number is varied between 500 and 700. However, the effects of these variables on the overall heat transfer coefficient are deeply investigated. Results demonstrate that both nanofluids show greater overall heat transfer coefficient in comparison with water up to 9%. Furthermore, increasing the nanoparticle concentration, air velocity, and nanofluid velocity enhances the overall heat transfer coefficient. In contrast, increasing the nanofluid inlet temperature, lower overall heat transfer coefficient was recorded. -- Highlights: ► Overall heat transfer coefficient in the car radiator measured experimentally. ► Nanofluids showed greater heat transfer performance comparing with water. ► Increasing liquid and air Re increases the overall heat transfer coefficient. ► Increasing the inlet liquid temperature decreases the overall heat transfer coefficient

  1. Decomposition of dilute residual active chlorine in sea-water

    International Nuclear Information System (INIS)

    Yoshinaga, Tetsutaro; Kawano, Kentaro; Yanagase, Kenjiro; Shiga, Akira

    1985-01-01

    Coastal industries such as power stations require enormous quantities of sea-water for cooling, but the marine organisms in it often result in fouling and/or blockade of the circulating water condenser and pipeworks. To prevent this, chlorine, or hypochlorite by the direct electrolysis of sea-water have been added. Environmental concerns, however, dictate that the residual chlorine concentration at the outlet should be less than the regulated value (0.02 ppm). Methods for decomposing dilute residual chlorine solutions were therefore studied. It was found that: 1) The addition of (raw) sea-water to the sea-water which passed through the condenser lowered the residual chlorine concentration to an greater extent than could be expected by dilution only. 2) Ozonation of the residual chlorine solution led to degradation of OCl - , but in solutions with a residual chlorine concentrations of less than 3 -- 4 ppm, ozonation had no effect. 3) Irradiation with ultra violet light (254 nm) decomposed the residual chlorine. Under the present work conditions (25 0 C: pH 8; depth 10 mm), nearly first order kinetics were to hold [da/dt = ksub((1)) (1-a)sup(n)]. There is a proportional relationship between the kinetic constant (k) and illuminous intensity (L), i.e., ksub((1))[C 0 sup(Cl 2 ): 10 ppm] = 6.56 x 10 -5 L (L = 0 -- 1000 lx). Thus, the use of both sea-water addition and UV irradiation provides a probable method for decomposing a residual chlorine to the expected concentration. (author)

  2. Frictional coefficient depending on active friction radius with BPV ...

    African Journals Online (AJOL)

    Frictional coefficient depending on active friction radius with BPV and BTV in automobile disc braking system. ... International Journal of Engineering, Science and Technology. Journal Home · ABOUT ... AJOL African Journals Online. HOW TO ...

  3. Overview of models allowing calculation of activity coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Jaussaud, C.; Sorel, C

    2004-07-01

    Activity coefficients must be estimated to accurately quantify the extraction equilibrium involved in spent fuel reprocessing. For these calculations, binary data are required for each electrolyte over a concentration range sometimes exceeding the maximum solubility. The activity coefficients must be extrapolated to model the behavior of binary supersaturated aqueous solution. According to the bibliography, the most suitable models are based on the local composition concept. (authors)

  4. Distributing Correlation Coefficients of Linear Structure-Activity/Property Models

    Directory of Open Access Journals (Sweden)

    Sorana D. BOLBOACA

    2011-12-01

    Full Text Available Quantitative structure-activity/property relationships are mathematical relationships linking chemical structure and activity/property in a quantitative manner. These in silico approaches are frequently used to reduce animal testing and risk-assessment, as well as to increase time- and cost-effectiveness in characterization and identification of active compounds. The aim of our study was to investigate the pattern of correlation coefficients distribution associated to simple linear relationships linking the compounds structure with their activities. A set of the most common ordnance compounds found at naval facilities with a limited data set with a range of toxicities on aquatic ecosystem and a set of seven properties was studied. Statistically significant models were selected and investigated. The probability density function of the correlation coefficients was investigated using a series of possible continuous distribution laws. Almost 48% of the correlation coefficients proved fit Beta distribution, 40% fit Generalized Pareto distribution, and 12% fit Pert distribution.

  5. Transport coefficients and orientational distributions of dilute colloidal dispersions composed of hematite particles (for an external magnetic field parallel to the angular velocity vector of simple shear flow)

    International Nuclear Information System (INIS)

    Satoh, Akira; Hayasaka, Ryo; Majima, Tamotsu

    2008-01-01

    We have treated a dilute dispersion composed of ferromagnetic rodlike particles with a magnetic moment normal to the particle axis, such as hematites, to investigate the influences of the magnetic field strength, shear rate, and random forces on the orientational distribution of rodlike particles and also on transport coefficients, such as viscosity and diffusion coefficient. In the present analysis, these rodlike particles are assumed to conduct the rotational Brownian motion in a simple shear flow as well as an external magnetic field. The results obtained here are summarized as follows. In the case of a strong magnetic field and a smaller shear rate, the rodlike particle can freely rotate in the xy-plane with the magnetic moment continuing to point the magnetic field direction. On the other hand, for a strong shear flow, the particle has a tendency to incline in the flow direction with the magnetic moment pointing to the magnetic field direction. In the case of the magnetic field applied normal to the direction of the sedimentation, the diffusion coefficient gives rise to smaller values than expected, since the rodlike particle sediments with the particle axis inclining toward directions normal to the movement direction and, of course, toward the direction along that direction

  6. The error analysis of the determination of the activity coefficients via the isopiestic method

    International Nuclear Information System (INIS)

    Zhou Jun; Chen Qiyuan; Fang Zheng; Liang Yizeng; Liu Shijun; Zhou Yong

    2005-01-01

    Error analysis is very important to experimental designs. The error analysis of the determination of activity coefficients for a binary system via the isopiestic method shows that the error sources include not only the experimental errors of the analyzed molalities and the measured osmotic coefficients, but also the deviation of the regressed values from the experimental data when the regression function is used. It also shows that the accurate chemical analysis of the molality of the test solution is important, and it is preferable to keep the error of the measured osmotic coefficients changeless in all isopiestic experiments including those experiments on the very dilute solutions. The isopiestic experiments on the dilute solutions are very important, and the lowest molality should be low enough so that a theoretical method can be used below the lowest molality. And it is necessary that the isopiestic experiment should be done on the test solutions of lower than 0.1 mol . kg -1 . For most electrolytes solutions, it is usually preferable to require the lowest molality to be less than 0.05 mol . kg -1 . Moreover, the experimental molalities of the test solutions should be firstly arranged by keeping the interval of the logarithms of the molalities nearly constant, and secondly more number of high molalities should be arranged, and we propose to arrange the experimental molalities greater than 1 mol . kg -1 according to some kind of the arithmetical progression of the intervals of the molalities. After experiments, the error of the calculated activity coefficients of the solutes could be calculated from the actually values of the errors of the measured isopiestic molalities and the deviations of the regressed values from the experimental values with our obtained equations

  7. Anomalous behavior of the diffusion coefficient in thin active films

    International Nuclear Information System (INIS)

    Basu, Abhik; Joanny, Jean-Francois; Prost, Jacques; Jülicher, Frank

    2012-01-01

    Inspired by recent experiments in cell biology, we elucidate the visco-elastic properties of an active gel by studying the dynamics of a small tracer particle inside it. In a stochastic hydrodynamic approach for an active gel of finite thickness L, we calculate the mean square displacement of a particle. These particle displacements are governed by fluctuations in the velocity field. We characterize the short-time behavior when the gel is a solid as well as the limit of long times when the gel becomes a fluid and the particle shows simple diffusion. Active stresses together with local polar order give rise to velocity fluctuations that lead to characteristic behaviors of the diffusion coefficient that differ fundamentally from those found in a passive system: the diffusion coefficient can depend on system size and diverges as L approaches an instability threshold. Furthermore, the diffusion coefficient becomes independent of the particle size in this case. (paper)

  8. ACTIVITY OF LEAF-CUTTING ANT Atta sexdens piriventris SUBMITED TO HIGH DILUTION HOMEOPATHIC PREPARATIONS

    Directory of Open Access Journals (Sweden)

    Alexandre Giesel

    2013-02-01

    Full Text Available The effect of high dilution preparations on the movement and foraging activities of Atta sexdens piriventris was evaluated. Five colonies of ants were located on each of the five experimental areas using a randomized complete block design. Three main forage trails from each colony were selected from where evaluations were made. Ten mL of high dilution preparation of Atta sexdens piriventris nosodes and Belladonna homeopathy solution were sprayed over 0.5 m of each selected trail, 1.0 m far from the nest. The controls were pure water and non treated trails. Applications were made daily during 10 days. The total number of ants moving on each trail one meter away from the nest, carrying or not plant fragments, were assessed before the daily application. Dilution preparations at 30CH (thirtieth centesimal Hahnemannian dilution of A. sexdens piriventris nosodes and Belladonna reduced the activities of ants from the fifth day after the first application. The treatment effect lasted more than 20 days after the last application. The use of preparation at 30CH dilution order to reduce the foraging activity of leaf-cutting ants is a potential non residual method to manage leaf-cutting ants.

  9. Modification of van La ar activity coefficient model

    International Nuclear Information System (INIS)

    Vakili-Nezhaad, G. R.; Modarress, H.; Mansoori, G. A.

    2001-01-01

    Based on statistical and mechanical arguments, the original van La ar activity coefficient model has been improved by reasonable assumptions. This modifications has been done by replacing the van der Waals equation of state with the Redlich-K wong equation of state in the formulation of van La ar with consistent mixing rules for the energy and volume parameters of this equation of state (a mix , b mix ). Other equations of state, such as the Soave modification of the Redlich-K wong equation of state, P eng-Robinson and Mohsen-Nia, Modarress and Mansoori equations of state, have been introduced in the formulation of van La ar for the activity coefficients of the components present in the binary liquid mixtures, and their effects on the accuracy of the resultant activity coefficient models have been examined. The results of these revised models have been compared with the experimental data and it was found that the Redlich-K wong equation of state with the van der Waals mixing rules for the volume and energy parameters of this equation, is the best choice among these equations of state. In addition, it can improve the original van La ar activity coefficient model and, therefore a better agreement with the experimental data is obtained

  10. New Insights into Butyrylcholinesterase Activity Assay: Serum Dilution Factor as a Crucial Parameter.

    Directory of Open Access Journals (Sweden)

    Joanna Jońca

    Full Text Available Butyrylcholinesterase (BChE activity assay and inhibitor phenotyping can help to identify patients at risk of prolonged paralysis following the administration of neuromuscular blocking agents. The assay plays an important role in clinical chemistry as a good diagnostic marker for intoxication with pesticides and nerve agents. Furthermore, the assay is also commonly used for in vitro characterization of cholinesterases, their toxins and drugs. There is still lack of standardized procedure for measurement of BChE activity and many laboratories use different substrates at various concentrations. The purpose of this study was to validate the BChE activity assay to determine the best dilution of human serum and the most optimal concentration of substrates and inhibitors. Serum BChE activity was measured using modified Ellman's method applicable for a microplate reader. We present our experience and new insights into the protocol for high-throughput routine assays of human plasma cholinesterase activities adapted to a microplate reader. During our routine assays used for the determination of BChE activity, we have observed that serum dilution factor influences the results obtained. We show that a 400-fold dilution of serum and 5mM S-butyrylthiocholine iodide can be successfully used for the accurate measurement of BChE activity in human serum. We also discuss usage of various concentrations of dibucaine and fluoride in BChE phenotyping. This study indicates that some factors of such a multicomponent clinical material like serum can influence kinetic parameters of the BChE. The observed inhibitory effect is dependent on serum dilution factor used in the assay.

  11. Molar mass, radius of gyration and second virial coefficient from new static light scattering equations for dilute solutions: application to 21 (macro)molecules.

    Science.gov (United States)

    Illien, Bertrand; Ying, Ruifeng

    2009-05-11

    New static light scattering (SLS) equations for dilute binary solutions are derived. Contrarily to the usual SLS equations [Carr-Zimm (CZ)], the new equations have no need for the experimental absolute Rayleigh ratio of a reference liquid and solely rely on the ratio of scattered intensities of solutions and solvent. The new equations, which are based on polarizability equations, take into account the usual refractive index increment partial differential n/partial differential rho(2) complemented by the solvent specific polarizability and a term proportional to the slope of the solution density rho versus the solute mass concentration rho(2) (density increment). Then all the equations are applied to 21 (macro)molecules with a wide range of molar mass (0.2equations clearly achieve a better agreement with supplier M values. For macromolecules (M>500 kg mol(-1)), for which the scattered intensity is no longer independent of the scattering angle, the new equations give the same value of the radius of gyration as the CZ equation and consistent values of the second virial coefficient.

  12. Gas-surface interactions using accommodation coefficients for a dilute and a dense gas in a micro/nano-channel : heat flux predictions using combined molecular dynamics and Monte Carlo techniques

    NARCIS (Netherlands)

    Gaastra - Nedea, S.V.; Steenhoven, van A.A.; Markvoort, A.J.; Spijker, P.; Giordano, D.

    2014-01-01

    The influence of gas-surface interactions of a dilute gas confined between two parallel walls on the heat flux predictions is investigated using a combined Monte Carlo (MC) and molecular dynamics (MD) approach. The accommodation coefficients are computed from the temperature of incident and

  13. Synthesis of nano-sized amorphous boron powders through active dilution self-propagating high-temperature synthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jilin [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Gu, Yunle [School of Material Science and Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); Li, Zili [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Wang, Weimin, E-mail: wangwm@hotmail.com [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Fu, Zhengyi [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

    2013-06-01

    Graphical abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed. Highlights: ► Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis method. ► The morphology, particle size and purity of the samples could be effectively controlled via changing the endothermic rate. ► The diluter KBH{sub 4} played an important role in active dilution synthesis of amorphous nano-sized boron powders. ► The active dilution method could be further popularized and become a common approach to prepare various inorganic materials. - Abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method at temperatures ranging from 700 °C to 850 °C in a SHS furnace using Mg, B{sub 2}O{sub 3} and KBH{sub 4} as raw materials. Samples were characterized by X-ray powder diffraction (XRD), Laser particle size analyzer, Fourier transform infrared spectra (FTIR), X-ray energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission TEM (HRTEM). The boron powders demonstrated an average particle size of 50 nm with a purity of 95.64 wt.%. The diluter KBH{sub 4} played an important role in the active dilution synthesis of amorphous nano-sized boron powders. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed.

  14. Synthesis of nano-sized amorphous boron powders through active dilution self-propagating high-temperature synthesis method

    International Nuclear Information System (INIS)

    Wang, Jilin; Gu, Yunle; Li, Zili; Wang, Weimin; Fu, Zhengyi

    2013-01-01

    Graphical abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed. Highlights: ► Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis method. ► The morphology, particle size and purity of the samples could be effectively controlled via changing the endothermic rate. ► The diluter KBH 4 played an important role in active dilution synthesis of amorphous nano-sized boron powders. ► The active dilution method could be further popularized and become a common approach to prepare various inorganic materials. - Abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method at temperatures ranging from 700 °C to 850 °C in a SHS furnace using Mg, B 2 O 3 and KBH 4 as raw materials. Samples were characterized by X-ray powder diffraction (XRD), Laser particle size analyzer, Fourier transform infrared spectra (FTIR), X-ray energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission TEM (HRTEM). The boron powders demonstrated an average particle size of 50 nm with a purity of 95.64 wt.%. The diluter KBH 4 played an important role in the active dilution synthesis of amorphous nano-sized boron powders. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed

  15. Osmotic and activity coefficients of triorganophosphates in n-octane

    International Nuclear Information System (INIS)

    Sagert, N.H.; Lau, D.W.P.

    1982-01-01

    Vapour pressure osmometry was used to measure osmotic coefficients for tributylphosphate (TBP), tricresylphosphate (TCP), and triethylhexylphosphate (THEP) in n-octane at 30, 40, 50, and 60 0 C and at molalities up to 0.3 mol/kg. Activity coefficients and excess thermodynamic properties (unsymmetrical definition) were calculated from these osmotic coefficients. At 30 0 C, the excess Gibbs free energies for 0.1 mol of solute in 1.0 kg n-octane were -42 J, -66 J, and -20 J for TBP, TCP, and TEHP, respectively. The more ideal behavior of the TEHP-octane system is attributed to the increasing importance of hydrocarbon-hydrocarbon interactions as the chain length is increased. The excess enthalpies for 0.1 mol of solute in 1.0 kg of solvent were -100 J, and -300 J, and -150 J for TBP, TCP, and TEHP, respectively. Thus, association of these solutes arises primarily from entropic effects. Our data could generally be accommodated adequately by postulating association of monomers into dimmers. The exception was TCP at lower temperatures, where more complex models were required

  16. Kinetic attractor phase diagrams of active nematic suspensions: the dilute regime.

    Science.gov (United States)

    Forest, M Gregory; Wang, Qi; Zhou, Ruhai

    2015-08-28

    Large-scale simulations by the authors of the kinetic-hydrodynamic equations for active polar nematics revealed a variety of spatio-temporal attractors, including steady and unsteady, banded (1d) and cellular (2d) spatial patterns. These particle scale activation-induced attractors arise at dilute nanorod volume fractions where the passive equilibrium phase is isotropic, whereas all previous model simulations have focused on the semi-dilute, nematic equilibrium regime and mostly on low-moment orientation tensor and polarity vector models. Here we extend our previous results to complete attractor phase diagrams for active nematics, with and without an explicit polar potential, to map out novel spatial and dynamic transitions, and to identify some new attractors, over the parameter space of dilute nanorod volume fraction and nanorod activation strength. The particle-scale activation parameter corresponds experimentally to a tunable force dipole strength (so-called pushers with propulsion from the rod tail) generated by active rod macromolecules, e.g., catalysis with the solvent phase, ATP-induced propulsion, or light-activated propulsion. The simulations allow 2d spatial variations in all flow and orientational variables and full spherical orientational degrees of freedom; the attractors correspond to numerical integration of a coupled system of 125 nonlinear PDEs in 2d plus time. The phase diagrams with and without the polar interaction potential are remarkably similar, implying that polar interactions among the rodlike particles are not essential to long-range spatial and temporal correlations in flow, polarity, and nematic order. As a general rule, above a threshold, low volume fractions induce 1d banded patterns, whereas higher yet still dilute volume fractions yield 2d patterns. Again as a general rule, varying activation strength at fixed volume fraction induces novel dynamic transitions. First, stationary patterns saturate the instability of the isotropic

  17. Assessing the reliability of predictive activity coefficient models for molecules consisting of several functional groups

    Directory of Open Access Journals (Sweden)

    R. P. Gerber

    2013-03-01

    Full Text Available Currently, the most successful predictive models for activity coefficients are those based on functional groups such as UNIFAC. In contrast, these models require a large amount of experimental data for the determination of their parameter matrix. A more recent alternative is the models based on COSMO, for which only a small set of universal parameters must be calibrated. In this work, a recalibrated COSMO-SAC model was compared with the UNIFAC (Do model employing experimental infinite dilution activity coefficient data for 2236 non-hydrogen-bonding binary mixtures at different temperatures. As expected, UNIFAC (Do presented better overall performance, with a mean absolute error of 0.12 ln-units against 0.22 for our COSMO-SAC implementation. However, in cases involving molecules with several functional groups or when functional groups appear in an unusual way, the deviation for UNIFAC was 0.44 as opposed to 0.20 for COSMO-SAC. These results show that COSMO-SAC provides more reliable predictions for multi-functional or more complex molecules, reaffirming its future prospects.

  18. Influences of the chemical structure of entrainers on the activity coefficients in presence of biodiesel

    International Nuclear Information System (INIS)

    Mäder, A; Fleischmann, A; Fang, Ye; Krahl, J; Ruck, W

    2012-01-01

    In this work we analyzed the strength of the intermolecular forces between biodiesel and the entrainer and their influence on the entrainer's ability to interact with biodiesel. Furthermore we investigated the influence of the chemical structure of an entrainer to the interaction with biodiesel. For this purpose the activity coefficients γ ∞ at infinite dilution of acids, aldehydes, ketones and alcohols in biodiesel were measured with the method of headspace gas chromatography (HSGC). Short-chained acids showed the highest interaction of the analyzed entrainers caused by their ability to build hydrogen bonds with biodiesel. Increased chain length of the acids cause reduced interaction with biodiesel, which is mainly due to the higher obstruction of the acid molecule and therefore the reduced ability to build hydrogen bonds with biodiesel. Aldehydes, ketones and alcohols showed lower interaction with biodiesel compared to the acids. Longer-chained alcohols showed increased interaction with biodiesel due to the raised London Forces and an inductive +I effect of the molecule chain.

  19. The effect of ultrasound on particle size, color, viscosity and polyphenol oxidase activity of diluted avocado puree.

    Science.gov (United States)

    Bi, Xiufang; Hemar, Yacine; Balaban, Murat O; Liao, Xiaojun

    2015-11-01

    The effect of ultrasound treatment on particle size, color, viscosity, polyphenol oxidase (PPO) activity and microstructure in diluted avocado puree was investigated. The treatments were carried out at 20 kHz (375 W/cm(2)) for 0-10 min. The surface mean diameter (D[3,2]) was reduced to 13.44 μm from an original value of 52.31 μm by ultrasound after 1 min. A higher L(∗) value, ΔE value and lower a(∗) value was observed in ultrasound treated samples. The avocado puree dilution followed pseudoplastic flow behavior, and the viscosity of diluted avocado puree (at 100 s(-1)) after ultrasound treatment for 1 min was 6.0 and 74.4 times higher than the control samples for dilution levels of 1:2 and 1:9, respectively. PPO activity greatly increased under all treatment conditions. A maximum increase of 25.1%, 36.9% and 187.8% in PPO activity was found in samples with dilution ratios of 1:2, 1:5 and 1:9, respectively. The increase in viscosity and measured PPO activity might be related to the decrease in particle size. The microscopy images further confirmed that ultrasound treatment induced disruption of avocado puree structure. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Traceable mean activity coefficients and osmotic coefficients in aqueous magnesium chloride solutions at T = 298.15 K up to a molality of 3.0 mol · kg−1

    International Nuclear Information System (INIS)

    Partanen, Jaakko I.

    2013-01-01

    Highlights: • This work reports new equations for thermodynamic activity quantities in aqueous MgCl 2 solutions. • The new equations are functionally the same as those obtained previously solutions of CaCl 2 and uni-univalent electrolytes. • The new activity and osmotic coefficients are fully traceable and transparent. • These new values were tested thoroughly with existing literature data. -- Abstract: The Hückel equation used in this study for the thermodynamic activity quantities in dilute MgCl 2 solutions up to an ionic strength (=I m ) of 1.5 mol · kg −1 contains two parameters being dependent on the electrolyte, i.e., those of B and b 1 . The former is linearly related to the ion-size parameter in the Debye–Hückel equation and the latter is the coefficient of the linear correction term with respect to the molality. For more concentrated solutions up to I m of 9.0 mol · kg −1 , an extended Hückel equation was used. For it, the Hückel equation was extended with a quadratic term in molality, and the coefficient of this term is the third parameter b 2 . Parameters B and b 1 for dilute MgCl 2 solutions were obtained from the isopiestic data of Robinson and Stokes for solutions of this salt and KCl [Trans. Faraday Soc. 36 (1940) 733] by using the previous Hückel parameters for dilute KCl solutions [J. Chem. Eng. Data 54 (2009) 208]. The resulting parameters for MgCl 2 solutions were successfully tested with all isopiestic data available in the literature for dilute solutions of this salt. For less dilute solutions, new values for parameters b 1 and b 2 were determined for the extended version of the Hückel equation of MgCl 2 solutions from the isopiestic data of Rard and Miller [J. Chem. Eng. Data 26 (1981) 38] for NaCl and MgCl 2 solutions but the dilute-solution value for parameter B was used. The previous extended Hückel equation for concentrated NaCl solutions was used in this estimation (see the KCl citation above). In the tests of the

  1. Simultaneous Description of Activity Coefficients and Solubility with eCPA

    DEFF Research Database (Denmark)

    Schlaikjer, Anders; Thomsen, Kaj; Kontogeorgis, Georgios

    2017-01-01

    with salt specific parameters. The focus is on accurate description of the salt solubility, and low deviation correlations are obtained for all salts investigated. The inclusion of the solubility data in the parametrization has, compared to parameters only parametrized to osmotic coefficients and activity...... coefficients, not significantly affected the deviations of the osmotic coefficients and activity coefficients. The average deviations of the activity coefficient does increase slightly and it was found that the increase in deviations was almost entirely due to reduced accuracy at high temperature and high...... molality. The model is, furthermore, compared to the activity coefficient model, Extended UNIQUAC. It is shown that the eCPA provides more accurate solubility description at higher temperatures than Extended UNIQUAC but also that Extended UNIQUAC is slightly better at describing the activity coefficients...

  2. Measurement of Activity Coefficients of Solvents in Poly ( ethylene oxide ) Using Gas-Chromatographic Method and Correlation by Polymer-ASOG; Poriechirenokishido chu no yobai katsuryo keisu no gasukuromatogurafu ho ni yoru sokutei to Polymer-ASOG ni yoru sokan

    Energy Technology Data Exchange (ETDEWEB)

    Tochigi, K.; Kurita, S.; Ohashi, M. [Yuki Gosei Kogyo Co. LTd., (Japan); Kojima, K. [Nihon University, Tokyo (Japan). Department of Industrial Chemistry

    1997-09-01

    Infinite dilution activity coefficients (353.15-393.15 K) of six solvents (benzene, toluene, p-xylene, cyclohexane, acetone and methylethylketone) and activity coefficient at finite concentrations (353.15 K, 373.15 K) of these solvents in poly (ethylene oxide) are measured using gas-chromatographic method. The experimental data are then correlated by a polymer-ASOG model. 18 refs., 2 figs., 3 tabs.

  3. Effect of flow rate on the adsorption coefficient of radioactive krypton on activated carbon

    International Nuclear Information System (INIS)

    Sun, L.S.C.; Underhill, D.W.

    1981-01-01

    For some time, there have been questions relative to the effect of carrier gas velocity on the adsorption coefficient for radioactive noble gases on activated charcoal. Resolution of these questions is particularly important in terms of developing standard procedures for determining such coefficients under laboratory conditions. Studies at the Harvard Air Cleaning Laboratory appear to confirm that the adsorption coefficient for radioactive krypton on activated charcoal is independent of the velocity of the carrier gas

  4. Estimation of saturation activities for activation experiments in CHARM and CSBF using Fluence Conversion Coefficients

    CERN Document Server

    Guerin, Helene Chloe; Iliopoulou, Elpida; CERN. Geneva. HSE Department

    2017-01-01

    As summer student at CERN, I have been working in the Radiation Protection group for 10 weeks. I worked with the \\textsc{Fluka} Monte Carlo simulation code, using Fluence Conversion Coefficients method to perform simulations to estimate the saturation activities for activation experiments in the \\textsc{CSBF} and the \\textsc{Charm} facility in the East Experimental Area. The provided results will be used to plan a Monte Carlo benchmark in the \\textsc{CSBF} during a beam period at the end of August 2017.

  5. Recovery of glycols, sugars, and Related Multiple -OH Compounds from Dilute-Aqueous Solution by Regenerable Adsorption onto Activated Carbons

    Energy Technology Data Exchange (ETDEWEB)

    Chinn, Daniel [Univ. of California, Berkeley, CA (United States)

    1999-06-01

    The present research explores the use of adsorption onto activated carbons as a means of recover glycerol, glycols, and sugars from dilute-aqueous solution. Our work is focused on understanding the mechanisms of adsorption onto carbons, assessing the degree of adsorption reversibility with precision, and implementing a bench-scale recovery process that results in a higher product concentration and reduction of the energy load for final purification.

  6. Measurement and modelling of mean activity coefficients of aqueous mixed electrolyte solution containing glycine

    Energy Technology Data Exchange (ETDEWEB)

    Dehghani, M.R. [Department of Chemical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of) ; Modarress, H. [Department of Chemical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of) ]. E-mail: hmodares@aut.ac.ir; Monirfar, M. [Department of Chemical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2006-08-15

    Electrochemical measurements were made on (H{sub 2}O + NaBr + K{sub 3}PO{sub 4} + glycine) mixtures at T = 298.15 K by using ion selective electrodes. The mean ionic activity coefficients of NaBr at molality 0.1 were determined at five K{sub 3}PO{sub 4} molalities (0.01, 0.03, 0.05, 0.07, and 0.1) mol . kg{sup -1}. The activity coefficients of glycine were evaluated from mean ionic activity coefficients of NaBr. The modified Pitzer equation was used to model the experimental data.

  7. Comparison between isotope dilution and activation analysis as a method for determining the macro content of mercury

    International Nuclear Information System (INIS)

    Soedyartomo; Sunoko, S.R.

    1975-01-01

    It is true that the mercury content in the environment should be measured accurately because of its toxicity even at levels of microgram order. The assessment of hazards due to environmental contamination with mercury is based on the results of the metal analysis in a number of different samples. Consequently, the study of the character of analytical methods used, i.e. their accuracy, precision, sensitivity, etc. is essential. A brief description on the microanalysis methods of mercury as given. The discussion of the results obtained from analysing some sludge and water by means of isotope dilution and destructive thermal neutron activation analysis is also presented. It is found that both methods are suitable for routine work. It can be concluded that the isotope dilution method has some advantages. It is more simple, more sensitive, more rapid, and has lower radiation hazard. (author)

  8. Sensitivity of the activated partial thromboplastin time, the dilute Russell's viper venom time, and the kaolin clotting time for the detection of the lupus anticoagulant: a direct comparison using plasma dilutions.

    Science.gov (United States)

    Martin, B A; Branch, D W; Rodgers, G M

    1996-01-01

    Increasing dilutions of lupus anticoagulant (LA) plasmas from twelve patients were used to directly compare the sensitivity of four tests for LA. The tests evaluated were the modified Bell and Alton activated partial thromboplastin time (APTT), an APTT using a commercially prepared partial thromboplastin (Platelin LS APTT), a modified dilute Russell's viper venom time (DRVVT), and a modified kaolin clotting time (KCT). LAs were detected in all twelve plasmas by each of three tests and eleven of twelve plasmas in a fourth test when undiluted patient plasma was used. Repeating the tests after diluting the LA plasmas with normal platelet-free plasma (PFP) showed that the KCT was the most sensitive test for LA, detecting eleven of twelve LAs at a dilution of 10% patient plasma and ten of twelve LAs at a dilution of 5% patient plasma. The modified Bell and Alton APTT and the modified DRVVT had similar sensitivities at a patient plasma concentration of 10%, detecting seven of twelve and eight of twelve LAs, respectively. The Platelin LS APTT detected only four of twelve LAs at a patient plasma concentration of 10%. Our results indicate that the modified KCT is a sensitive method for the detection of LAs. The modified Bell and Alton APTT and the DRVVT were less sensitive.

  9. Electrochemical performance of microporous and mesoporous activated carbons in neat and diluted 1-ethyl-3-methylimidazolium tetrafluoroborate

    Science.gov (United States)

    Kumagai, Seiji; Hatomi, Masaki; Tashima, Daisuke

    2017-03-01

    1-Ethyl-3-methylimidazolium tetrafluoroborate (EMIm·BF4), neat and diluted with propylene carbonate to 1 mol L-1, have been employed as electrolytes of electrical double-layer capacitors (EDLCs). The effects of microporosity and mesoporosity in activated carbon (AC) electrodes on the capacitive and resistive performances upon the use of neat and diluted EMIm·BF4 have been explored. In addition to cyclic voltammetry and galvanostatic charge-discharge tests, electrochemical impedance spectroscopy has been performed employing Kang's equivalent circuit model consisting of three resistances, three constant phase elements, and one bounded Warburg impedance. The overall impedance of the EDLC cell was separated into components of intrinsic resistance, bulk electrolyte, diffusion layer, and Helmholtz layer. The specific capacitance and the equivalent series resistance (ESR) of mesoporous AC were found to be highly dependent on the rate of ionic transfer. Lower cell voltage was identified as being responsible for lower specific capacitance and larger ESR of mesoporous AC, which was similarly seen in the neat and diluted EMIm·BF4, and could be alleviated by increasing the cell voltage. The inferior rate performance and the cell-voltage-dependent performance of mesoporous AC, which were more distinctly observed in the neat EMIm·BF4, could be attributed to the lower mobility of EMIm+ and BF4- in mesopores.

  10. Determination of gold of No. 501 uranium deposits and soil samples by cold leaching gold in dilute aqua regia and collection on activated charcoal

    International Nuclear Information System (INIS)

    Shen Maogen; Yao Liying.

    1989-01-01

    The gold determination method is described by cold leaching gold in dilute aqua regia and collection on activated charcoal and presents the results obtained in determining gold of uranium deposits and soil samples

  11. Simulating Osmotic Equilibria: A New Tool for Calculating Activity Coefficients in Concentrated Aqueous Salt Solutions.

    Science.gov (United States)

    Bley, Michael; Duvail, Magali; Guilbaud, Philippe; Dufrêche, Jean-François

    2017-10-19

    Herein, a new theoretical method is presented for predicting osmotic equilibria and activities, where a bulk liquid and its corresponding vapor phase are simulated by means of molecular dynamics using explicit polarization. Calculated time-averaged number density profiles provide the amount of evaporated molecules present in the vapor phase and consequently the vapor-phase density. The activity of the solvent and the corresponding osmotic coefficient are determined by the vapor density at different solute concentrations with respect to the reference vapor density of the pure solvent. With the extended Debye-Hückel equation for the activity coefficient along with the corresponding Gibbs-Duhem relation, the activity coefficients of the solutes are calculated by fitting the osmotic coefficients. A simple model based on the combination of Poisson processes and Maxwell-Boltzmann velocity distributions is introduced to interpret statistical phenomena observed during the simulations, which are related to evaporation and recondensation. This method is applied to aqueous dysprosium nitrate [Dy(NO 3 ) 3 ] solutions at different concentrations. The obtained densities of the liquid bulk and the osmotic and activity coefficients are in good agreement with the experimental results for concentrated and saturated solutions. Density profiles of the liquid-vapor interface at different concentrations provide detailed insight into the spatial distributions of all compounds.

  12. The possibility of determining the activity coefficients of individual ions from acid-base titration data

    Science.gov (United States)

    Jano, I.; Hardcastle, J. E.

    1998-07-01

    A method is described for obtaining the activity coefficients of individual ions from experimental titration data. For this purpose, a general polyprotic acid-base-titration-curve equation is derived. The equation allows obtaining the dissociation equilibrium constants of the acid and the ratio of the activity coefficient of each ion to the activity coefficient of the undissociated acid directly from the titration data. Results obtained are compared with coefficients calculated using Debye-Hückel equation. A general equation relating the ionic strength to the pH of the titration medium is also established. Une méthode pour l'obtention des coefficients d'activité des ions individuels à partir des données expérimentales de titrage est établie. À ce but, une équation générale est dérivée pour représenter la courbe de titrage d'un acide avec une base. Cette équation permet d'obtenir les constants d'équilibre de dissociation de l'acide et le rapport de coefficient d'activité de chaque ion au coefficient d'activité de l'acide non-dissocié à partir des données de titrage. Les résultats ainsi obtenus sont comparés avec les coefficients calculés à l'aide de l'équation de Debye-Hückel. Une équation liant la force ionique au pH du milieu est établie aussi.

  13. Determination of micro-quantities of several elements in soil solution by isotope dilution and activation analyses

    International Nuclear Information System (INIS)

    Cho, C.M.; Axmann, H.

    1965-01-01

    Determination of small quantities of plant nutrients in the soil solution of flooded rice soils is a difficult problem. The concentrations of Mn, Fe and P, for example, in some soil solutions are so small that no chemical method gives any accurate result. Neutron activation analysis was reported to give a much lower limit of detectability for several elements, while for elements with low-induced activity after neutron irradiation, substoichiometric isotopic dilution analysis was applied. One of the advantages of neutron activation analysis lies in the fact that simultaneous activation of every inducible element in a sample takes place. This gives an opportunity to determine many elements by one sample preparation and irradiation. This, however, is not a simple task since identification of the activated products and their quantitative estimation becomes very difficult. Certain operations of separation must be carried out before activity measurements. Ion-exchange resin columns and chemical separation following the addition of carriers were successfully used for the determination of many elements after neutron irradiation. These procedures, however, cannot be directly applied to the determination of the elements of agronomic interest. A procedure was developed to determine several elements of agronomic interest. Times of irradiation and cooling, quick separation by ion-exchange columns, together with chemical precipitation for β-emitters of relatively long half-lives, were all combined to get the maximum benefit from neutron activation analysis. For Fe, for which no satisfactory neutron activation analysis has yet been developed, a modified substoichiometric double isotope dilution procedure is applied

  14. Dilution Confusion: Conventions for Defining a Dilution

    Science.gov (United States)

    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…

  15. Activity Coefficients of Acetone-Chloroform Solutions: An Undergraduate Experiment. Undergraduate Experiment.

    Science.gov (United States)

    Ozog, J. Z.; Morrison, J. A.

    1983-01-01

    Presents information, laboratory procedures, and results of an undergraduate experiment in which activity coefficients for a two-component liquid-vapor system are determined. Working in pairs, students can perform the experiment with 10 solutions in a given three-hour laboratory period. (Author/JN)

  16. Measurement of activity coefficients of mixtures by head-space gas chromatography: general procedure.

    Science.gov (United States)

    Luis, Patricia; Wouters, Christine; Van der Bruggen, Bart; Sandler, Stanley I

    2013-08-09

    Head-space gas chromatography (HS-GC) is an applicable method to perform vapor-liquid equilibrium measurements and determine activity coefficients. However, the reproducibility of the data may be conditioned by the experimental procedure concerning to the automated pressure-balanced system. The study developed in this work shows that a minimum volume of liquid in the vial is necessary to ensure the reliability of the activity coefficients since it may become a parameter that influences the magnitude of the peak areas: the helium introduced during the pressurization step may produce significant variations of the results when too small volume of liquid is selected. The minimum volume required should thus be evaluated prior to obtain experimentally the concentration in the vapor phase and the activity coefficients. In this work, the mixture acetonitrile-toluene is taken as example, requiring a sample volume of more than 5mL (about more than 25% of the vial volume). The vapor-liquid equilibrium and activity coefficients of mixtures at different concentrations (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 molar fraction) and four temperatures (35, 45, 55 and 70°C) have been determined. Relative standard deviations (RSD) lower than 5% have been obtained, indicating the good reproducibility of the method when a sample volume larger than 5mL is used. Finally, a general procedure to measure activity coefficients by means of pressure-balanced head-space gas chromatography is proposed. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. A Study Of The Dilution Of Radio-Active Waste In The Rhone (1961); Etude de la dilution dans le rhone des effluents radioactifs du Centre de Marcoule (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Rodier, J; Scheidhauer, J; Marichal, M; Court, R [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1961-07-01

    The discharge into the Rhone of liquid radio-active waste from the Marcoule Centre necessitates a large number of measurements, in particular chemical and radio-chemical analysis of the waste, itself and of the waters of the Rhone both above arid below the point of discharge. The results thus obtained during 1960 made it possible to evaluate the total amount of active waste discharged and its dilution in the receiving medium. A statistical study of the results of the analysis of the Rhone waters shows that a satisfactory dilution of the waste occurs rapidly; the experimental results obtained with an experimental discharge of rhodamine are thus confirmed. (authors) [French] Le rejet au Rhone des effluents radioactifs liquides produits sur le Centre de Marcoule donne lieu a un grand nombre de mesures et en particulier d'analyses chimiques et radio-chimiques des effluents eux-memes ainsi que des eaux du Rhone avant et apres rejet. Au cours de l'annee 1960, l'ensemble des resultats ainsi obtenus a permis de dresser un bilan des activites rejetees et de leur dispersion dans le milieu recepteur. Une etude statistique des resultats d'analyses des eaux du Rhone montre qu'une dilution satisfaisante des effluents s'effectue rapidement confirmant ainsi les resultats obtenus lors d'un rejet experimental de rhodamine. (auteurs)

  18. Semi-analytical Model for Estimating Absorption Coefficients of Optically Active Constituents in Coastal Waters

    Science.gov (United States)

    Wang, D.; Cui, Y.

    2015-12-01

    The objectives of this paper are to validate the applicability of a multi-band quasi-analytical algorithm (QAA) in retrieval absorption coefficients of optically active constituents in turbid coastal waters, and to further improve the model using a proposed semi-analytical model (SAA). The ap(531) and ag(531) semi-analytically derived using SAA model are quite different from the retrievals procedures of QAA model that ap(531) and ag(531) are semi-analytically derived from the empirical retrievals results of a(531) and a(551). The two models are calibrated and evaluated against datasets taken from 19 independent cruises in West Florida Shelf in 1999-2003, provided by SeaBASS. The results indicate that the SAA model produces a superior performance to QAA model in absorption retrieval. Using of the SAA model in retrieving absorption coefficients of optically active constituents from West Florida Shelf decreases the random uncertainty of estimation by >23.05% from the QAA model. This study demonstrates the potential of the SAA model in absorption coefficients of optically active constituents estimating even in turbid coastal waters. Keywords: Remote sensing; Coastal Water; Absorption Coefficient; Semi-analytical Model

  19. Molecular radiotherapy: The NUKFIT software for calculating the time-integrated activity coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Kletting, P.; Schimmel, S.; Luster, M. [Klinik für Nuklearmedizin, Universität Ulm, Ulm 89081 (Germany); Kestler, H. A. [Research Group Bioinformatics and Systems Biology, Institut für Neuroinformatik, Universität Ulm, Ulm 89081 (Germany); Hänscheid, H.; Fernández, M.; Lassmann, M. [Klinik für Nuklearmedizin, Universität Würzburg, Würzburg 97080 (Germany); Bröer, J. H.; Nosske, D. [Bundesamt für Strahlenschutz, Fachbereich Strahlenschutz und Gesundheit, Oberschleißheim 85764 (Germany); Glatting, G. [Medical Radiation Physics/Radiation Protection, Medical Faculty Mannheim, Heidelberg University, Mannheim 68167 (Germany)

    2013-10-15

    Purpose: Calculation of the time-integrated activity coefficient (residence time) is a crucial step in dosimetry for molecular radiotherapy. However, available software is deficient in that it is either not tailored for the use in molecular radiotherapy and/or does not include all required estimation methods. The aim of this work was therefore the development and programming of an algorithm which allows for an objective and reproducible determination of the time-integrated activity coefficient and its standard error.Methods: The algorithm includes the selection of a set of fitting functions from predefined sums of exponentials and the choice of an error model for the used data. To estimate the values of the adjustable parameters an objective function, depending on the data, the parameters of the error model, the fitting function and (if required and available) Bayesian information, is minimized. To increase reproducibility and user-friendliness the starting values are automatically determined using a combination of curve stripping and random search. Visual inspection, the coefficient of determination, the standard error of the fitted parameters, and the correlation matrix are provided to evaluate the quality of the fit. The functions which are most supported by the data are determined using the corrected Akaike information criterion. The time-integrated activity coefficient is estimated by analytically integrating the fitted functions. Its standard error is determined assuming Gaussian error propagation. The software was implemented using MATLAB.Results: To validate the proper implementation of the objective function and the fit functions, the results of NUKFIT and SAAM numerical, a commercially available software tool, were compared. The automatic search for starting values was successfully tested for reproducibility. The quality criteria applied in conjunction with the Akaike information criterion allowed the selection of suitable functions. Function fit

  20. Negative Correlation between the Diffusion Coefficient and Transcriptional Activity of the Glucocorticoid Receptor.

    Science.gov (United States)

    Mikuni, Shintaro; Yamamoto, Johtaro; Horio, Takashi; Kinjo, Masataka

    2017-08-25

    The glucocorticoid receptor (GR) is a transcription factor, which interacts with DNA and other cofactors to regulate gene transcription. Binding to other partners in the cell nucleus alters the diffusion properties of GR. Raster image correlation spectroscopy (RICS) was applied to quantitatively characterize the diffusion properties of EGFP labeled human GR (EGFP-hGR) and its mutants in the cell nucleus. RICS is an image correlation technique that evaluates the spatial distribution of the diffusion coefficient as a diffusion map. Interestingly, we observed that the averaged diffusion coefficient of EGFP-hGR strongly and negatively correlated with its transcriptional activities in comparison to that of EGFP-hGR wild type and mutants with various transcriptional activities. This result suggests that the decreasing of the diffusion coefficient of hGR was reflected in the high-affinity binding to DNA. Moreover, the hyper-phosphorylation of hGR can enhance the transcriptional activity by reduction of the interaction between the hGR and the nuclear corepressors.

  1. Antioxidant activity of aqueous extract of noni in dilutent for ram semen cryopreservation

    Directory of Open Access Journals (Sweden)

    Ana Lauren Costa Nascimento

    2016-03-01

    Full Text Available Noni (Morinda citrifolia L. is a fruit consumed worldwide because of its nutritional and therapeutic properties resulting from the large amount of phenolic compounds, which has aroused interest of the scientific community. In order to identify new natural sources of antioxidants, the objective of this study was to evaluate the performance of noni in diluent for ram semen cryopreservation. A completely randomized design consisting of four treatments and three repetitions per treatment was used. The treatments differed in terms of the concentration of the aqueous extract of noni added to the diluent: control, no addition of the extract, and three concentrations (24, 72, and 120 µg/mL. The physical and chemical variables of the mature fruit were evaluated: total acidity (8.78, pH (4.12, and soluble solids (8.18%. The vitamin C content was 309.42 mg per 100 g fresh matter. The aqueous extract of noni was also evaluated regarding the quantity of total phenolic compounds, antioxidant activity, and lipid peroxidation inhibition capacity. The aqueous extract contained a moderate amount of phenolic compounds (47.96 ± 1.95 mg gallic acid equivalent/100 g extract. The concentrations of the aqueous extract of 72 and 120 µg/mL in diluent used for semen cryopreservation inhibited lipid peroxidation by 21.75% and 51.32%, respectively. There was no positive effect of the lowest concentration (24 µg/mL. The antioxidant activity index of noni was 33.33, corresponding to very strong antioxidant activity. The aqueous extract of noni exhibits very strong antioxidant activity and its addition to the diluent for semen cryopreservation at a concentration of 72 µg/mL is able to inhibit lipid peroxidation.

  2. Adsorption of Selected Pharmaceutical Compounds onto Activated Carbon in Dilute Aqueous Solutions Exemplified by Acetaminophen, Diclofenac, and Sulfamethoxazole

    Science.gov (United States)

    Chang, E.-E.; Wan, Jan-Chi; Liang, Chung-Huei; Dai, Yung-Dun; Chiang, Pen-Chi

    2015-01-01

    The adsorption of three pharmaceuticals, namely, acetaminophen, diclofenac, and sulfamethoxazole onto granular activated carbon (GAC), was investigated. To study competitive adsorption, both dynamic and steady-state adsorption experiments were conducted by careful selection of pharmaceuticals with various affinities and molecular size. The effective diffusion coefficient of the adsorbate was increased with decease in particle size of GAC. The adsorption affinity represented as Langmuir was consistent with the ranking of the octanol-water partition coefficient, K ow. The adsorption behavior in binary or tertiary systems could be described by competition adsorption. In the binary system adsorption replacement occurred, under which the adsorbate with the smaller K ow was replaced by the one with larger K ow. Results also indicated that portion of the micropores could be occupied only by the small target compound, but not the larger adsorbates. In multiple-component systems the competition adsorption might significantly be affected by the macropores and less by the meso- or micropores. PMID:26078989

  3. Molecular radiotherapy: the NUKFIT software for calculating the time-integrated activity coefficient.

    Science.gov (United States)

    Kletting, P; Schimmel, S; Kestler, H A; Hänscheid, H; Luster, M; Fernández, M; Bröer, J H; Nosske, D; Lassmann, M; Glatting, G

    2013-10-01

    Calculation of the time-integrated activity coefficient (residence time) is a crucial step in dosimetry for molecular radiotherapy. However, available software is deficient in that it is either not tailored for the use in molecular radiotherapy and/or does not include all required estimation methods. The aim of this work was therefore the development and programming of an algorithm which allows for an objective and reproducible determination of the time-integrated activity coefficient and its standard error. The algorithm includes the selection of a set of fitting functions from predefined sums of exponentials and the choice of an error model for the used data. To estimate the values of the adjustable parameters an objective function, depending on the data, the parameters of the error model, the fitting function and (if required and available) Bayesian information, is minimized. To increase reproducibility and user-friendliness the starting values are automatically determined using a combination of curve stripping and random search. Visual inspection, the coefficient of determination, the standard error of the fitted parameters, and the correlation matrix are provided to evaluate the quality of the fit. The functions which are most supported by the data are determined using the corrected Akaike information criterion. The time-integrated activity coefficient is estimated by analytically integrating the fitted functions. Its standard error is determined assuming Gaussian error propagation. The software was implemented using MATLAB. To validate the proper implementation of the objective function and the fit functions, the results of NUKFIT and SAAM numerical, a commercially available software tool, were compared. The automatic search for starting values was successfully tested for reproducibility. The quality criteria applied in conjunction with the Akaike information criterion allowed the selection of suitable functions. Function fit parameters and their standard

  4. Predicting the activity coefficients of free-solvent for concentrated globular protein solutions using independently determined physical parameters.

    Directory of Open Access Journals (Sweden)

    Devin W McBride

    Full Text Available The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent model, which has previously been shown to provide excellent prediction of the osmotic pressure of concentrated and crowded globular proteins in aqueous solutions up to near-saturation concentrations. Thus, this model uses only the independently determined, physically realizable quantities: mole fraction, solvent accessible surface area, and ion binding, in its prediction. Predictions are presented for the activity coefficients of free-solvent for near-saturated protein solutions containing either bovine serum albumin or hemoglobin. As a verification step, the predictability of the model for the activity coefficient of sucrose solutions was evaluated. The predicted activity coefficients of free-solvent are compared to the calculated activity coefficients of free-solvent based on osmotic pressure data. It is observed that the predicted activity coefficients are increasingly dependent on the solute-solvent parameters as the protein concentration increases to near-saturation concentrations.

  5. Activation of Spinal α2-Adrenoceptors Using Diluted Bee Venom Stimulation Reduces Cold Allodynia in Neuropathic Pain Rats

    Directory of Open Access Journals (Sweden)

    Suk-Yun Kang

    2012-01-01

    Full Text Available Cold allodynia is an important distinctive feature of neuropathic pain. The present study examined whether single or repetitive treatment of diluted bee venom (DBV reduced cold allodynia in sciatic nerve chronic constriction injury (CCI rats and whether these effects were mediated by spinal adrenergic receptors. Single injection of DBV (0.25 or 2.5 mg/kg was performed into Zusanli acupoint 2 weeks post CCI, and repetitive DBV (0.25 mg/kg was injected for 2 weeks beginning on day 15 after CCI surgery. Single treatment of DBV at a low dose (0.25 mg/kg did not produce any anticold allodynic effect, while a high dose of DBV (2.5 mg/kg significantly reduced cold allodynia. Moreover, this effect of high-dose DBV was completely blocked by intrathecal pretreatment of idazoxan (α2-adrenoceptor antagonist, but not prazosin (α1-adrenoceptor antagonist or propranolol (nonselective β-adrenoceptor antagonist. In addition, coadministration of low-dose DBV (0.25 mg/kg and intrathecal clonidine (α2-adrenoceptor agonist synergically reduced cold allodynia. On the other hand, repetitive treatments of low-dose DBV showing no motor deficit remarkably suppressed cold allodynia from 7 days after DBV treatment. This effect was also reversed by intrathecal idazoxan injection. These findings demonstrated that single or repetitive stimulation of DBV could alleviate CCI-induced cold allodynia via activation of spinal α2-adrenoceptor.

  6. Interpretation of biological-rate coefficients derived from radionuclide content, radionuclide concentration and specific activity experiments

    International Nuclear Information System (INIS)

    Vanderploeg, H.A.; Booth, R.S.

    1976-01-01

    Rigorous expressions are derived for the biological-rate coefficients (BRCs) determined from time-dependent measurements of three different dependent variables of radionuclide tracer experiments. These variables, which apply to a single organism, are radionuclide content, radionuclide concentration and specific activity. The BRCs derived from these variables have different mathematical expressions and, for high growth rates, their numerical values can be quite different. The precise mathematical expressions for the BRCs are presented here to aid modelers in selecting the correct parameters for their models and to aid experiments in interpreting their results. The usefulness of these three variables in quantifying elemental uptakes and losses by organisms is discussed. (U.K.)

  7. Correlation and prediction of osmotic coefficient and water activity of aqueous electrolyte solutions by a two-ionic parameter model

    International Nuclear Information System (INIS)

    Pazuki, G.R.

    2005-01-01

    In this study, osmotic coefficients and water activities in aqueous solutions have been modeled using a new approach based on the Pitzer model. This model contains two physically significant ionic parameters regarding ionic solvation and the closest distance of approach between ions in a solution. The proposed model was evaluated by estimating the osmotic coefficients of nine electrolytes in aqueous solutions. The obtained results showed that the model is suitable for predicting the osmotic coefficients in aqueous electrolyte solutions. Using adjustable parameters, which have been calculated from regression between the experimental osmotic coefficient and the results of this model, the water activity coefficients of aqueous solutions were calculated. The average absolute relative deviations of the osmotic coefficients between the experimental data and the calculated results were in agreement

  8. Early interglacial carbonate-dilution events in the South China Sea: Implications for strengthened typhoon activities over subtropical East Asia

    Science.gov (United States)

    Huang, Enqing; Tian, Jun; Qiao, Peijun; Wan, Sui; Xie, Xin; Yang, Wenguang

    2015-10-01

    A compilation of many late Quaternary marine sediment records from the northern South China Sea (SCS) continental slope confirms 15-50% reductions in sedimentary calcium carbonate concentrations between 11.0 and 8.5 ka BP in the early Holocene. This low carbonate% event occurred at a time when the regional sea level rose from -50 m to -10 m, which drowned large areas of continental shelves especially those near and within the Taiwan Strait. This event is associated with a significant increase in bulk sedimentation rates on the upper continental slope and the relative abundance of fine-grained detritus. Sediment provenance analyses suggest a dominant terrigenous input from Taiwan and a minor contribution from Luzon during the low carbonate% event, similar to the background terrigenous deposition in other periods of the Holocene. Two comparable low carbonate% events, respectively from the beginning of marine isotope stages 5.5 and 7.3, have also been recognized, pointing to similar causal factors. While carbonate dissolution and carbonate accumulation rate should not have been responsible, increased terrigenous input and dilution is considered as the main cause for the recurrent low carbonate% events in early interglacials. We further hypothesize that, during early interglacials, fluvial sediment discharge from Taiwan and Luzon intensified due to stronger typhoon activities, and massive fine-grained sediments from these two end members may have been transported to the northern SCS continental slope via surface and deep ocean currents. The conjecture of strengthened typhoon activities over East Asia during the early Holocene is supported by high ocean heat contents in the West Pacific Warm Pool area with the prevailing La Niña-like conditions.

  9. Application of several activity coefficient models to water-organic-electrolyte aerosols of atmospheric interest

    Directory of Open Access Journals (Sweden)

    T. Raatikainen

    2005-01-01

    Full Text Available In this work, existing and modified activity coefficient models are examined in order to assess their capabilities to describe the properties of aqueous solution droplets relevant in the atmosphere. Five different water-organic-electrolyte activity coefficient models were first selected from the literature. Only one of these models included organics and electrolytes which are common in atmospheric aerosol particles. In the other models, organic species were solvents such as alcohols, and important atmospheric ions like NH4+ could be missing. The predictions of these models were compared to experimental activity and solubility data in aqueous single electrolyte solutions with 31 different electrolytes. Based on the deviations from experimental data and on the capabilities of the models, four predictive models were selected for fitting of new parameters for binary and ternary solutions of common atmospheric electrolytes and organics. New electrolytes (H+, NH4+, Na+, Cl-, NO3- and SO42- and organics (dicarboxylic and some hydroxy acids were added and some modifications were made to the models if it was found useful. All new and most of the existing parameters were fitted to experimental single electrolyte data as well as data for aqueous organics and aqueous organic-electrolyte solutions. Unfortunately, there are very few data available for organic activities in binary solutions and for organic and electrolyte activities in aqueous organic-electrolyte solutions. This reduces model capabilities in predicting solubilities. After the parameters were fitted, deviations from measurement data were calculated for all fitted models, and for different data types. These deviations and the calculated property values were compared with those from other non-electrolyte and organic-electrolyte models found in the literature. Finally, hygroscopic growth factors were calculated for four 100 nm organic-electrolyte particles and these predictions were compared to

  10. Study of the influence of surfactants on the activity coefficients and mass transfer coefficients of methanol in aqueous mixtures by reversed-flow gas chromatography.

    Science.gov (United States)

    Kotsalos, Efthimios; Brezovska, Boryana; Sevastos, Dimitrios; Vagena, Artemis; Koliadima, Athanasia; Kapolos, John; Karaiskakis, George

    2017-11-17

    This work focuses on the influences of surfactants on the activity coefficients, γ, of methanol in binary mixtures with water, as well as on the mass transfer coefficients, k c , for the evaporation of methanol, which is a ubiquitous component in the troposphere, from mixtures of methanol with water at various surfactant's and methanol's concentrations. The technique used is the Reversed-Flow Gas Chromatography (R.F.G.C.), a version of Inverse Gas Chromatography, which allows determining both parameters by performing only one experiment for the k c parameter and two experiments for the γ parameter. The k c and γ values decrease in the presence of the three surfactants used (CTAB, SDS, TRITON X-100) at all methanol's and surfactant's concentrations. The decrease in the methanol's molar fraction, at constant number of surfactant films leads to a decrease in the k c and γ values, while the decrease in the surfactant's concentration, at constant methanol's molar fraction leads to an increase in both the k c and γ parameters. Mass transfer coefficients for the evaporation of methanol at the surfactant films, are also calculated which are approximately between 4 and 5 orders of magnitude larger than the corresponding mass transfer coefficients at the liquid films. Finally, thicknesses of the boundary layer of methanol in the mixtures of methanol with water were determined. The quantities found are compared with those given in the literature or calculated theoretically using various empirical equations. The precision of the R.F.G.C. method for measuring γ and k c parameters is approximately high (94.3-98.0%), showing that R.F.G.C. can be used with success not only for the thermodynamic study of solutions, but also for the interphase transport. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Self-shielding coefficient and thermal flux depression factor of voluminous sample in neutron activation analysis

    International Nuclear Information System (INIS)

    Noorddin Ibrahim; Rosnie Akang

    2009-01-01

    Full text: One of the major problems encountered during the irradiation of large inhomogeneous samples in performing activation analysis using neutron is the perturbation of the neutron field due to absorption and scattering of neutron within the sample as well as along the neutron guide in the case of prompt gamma activation analysis. The magnitude of this perturbation shown by self-shielding coefficient and flux depression depend on several factors including the average neutron energy, the size and shape of the sample, as well as the macroscopic absorption cross section of the sample. In this study, we use Monte Carlo N-Particle codes to simulate the variation of neutron self-shielding coefficient and thermal flux depression factor as a function of the macroscopic thermal absorption cross section. The simulation works was carried out using the high performance computing facility available at UTM while the experimental work was performed at the tangential beam port of Reactor TRIGA PUSPATI, Malaysia Nuclear Agency. The neutron flux measured along the beam port is found to be in good agreement with the simulated data. Our simulation results also reveal that total flux perturbation factor decreases as the value of absorption increases. This factor is close to unity for low absorbing sample and tends towards zero for strong absorber. In addition, sample with long mean chord length produces smaller flux perturbation than the shorter mean chord length. When comparing both the graphs of self-shielding factor and total disturbance, we can conclude that the total disturbance of the thermal neutron flux on the large samples is dominated by the self-shielding effect. (Author)

  12. Adjustment of activity coefficients as a function of changes in temperature, using the SIT

    International Nuclear Information System (INIS)

    Giffaut, E.; Vitorge, P.; Capdevila, H.

    1993-11-01

    The aim of this work is to propose and to check approximations to calculate from only a few experimental measurements, ionic strength, I, and temperature, T, influences on Gibbs energy, G, redox formal potential, E, and standard equilibrium constant, K. Series expansions versus T are first used: S and Cp/2T a are typically the -G first and second order terms. In the same way, -ΔH and T 2 ΔCp/2 are the first and second order terms of R in K expansions versus 1/T. This type of approximation is discussed for the E of the M 4+ /M 3+ , MO 2 2+ /MO 2 + and MO 2 (CO 3 ) 3 4- /MO 2 (CO 3 ) 3 5- couples (M = U or Pu) measured from 5 to 70 deg C, for the standard ΔG of some solid U compounds, calculated from 17 to 117 deg C, and for ΔCp, ΔG and Ig K of the CO 2 (aq)/HCO 3 - equilibrium from 0 to 150 deg C. Excess functions, X ex , are then calculated from activity coefficients, γ: enthalpy, H, or heat capacity, Cp, adjustment as a function of I changes is needed only when the γ adjustment as a function of T changes is needed. The SIT coefficient, ε, variations with T, are small and roughly linear for the above redox equilibria and for chloride electrolytes mean γ: first order expansion seems enough to deduce ε, and then the excess functions G ex , S ex and H ex , in this T range; but second order expansion is more consistent to estimate Cp ex . (authors). 25 refs., 3 tabs., 1 fig

  13. Release-Active Dilutions of Diclofenac Enhance Anti-inflammatory Effect of Diclofenac in Carrageenan-Induced Rat Paw Edema Model

    OpenAIRE

    Sakat, Sachin S.; Mani, Kamaraj; Demidchenko, Yulia O.; Gorbunov, Evgeniy A.; Tarasov, Sergey A.; Mathur, Archna; Epstein, Oleg I.

    2013-01-01

    The study was aimed to investigate the effect of technologically treated diclofenac (release-active dilutions of diclofenac (RAD of diclofenac)) on anti-inflammatory activity of diclofenac in carrageenan-induced rat paw edema model. Ninety male Wistar albino rats (6–8 weeks) divided into nine groups (n = 10) were used. Anti-inflammatory activity was assessed at 1, 2, 3, 4, and 6 h after subplantar injection of carrageenan (0.1 ml of a 1 % solution in normal saline). Diclofenac alone was studi...

  14. Analysis of the variation of the activity of a "9"9"mTc sample after dilution with saline solution

    International Nuclear Information System (INIS)

    Kuahara, L.T.; Correa, E.L.; Potiens, M.P.A.

    2016-01-01

    The activity meter is essential equipment in nuclear medicine services.To ensure its good operation and know the factors which may influence its readings is vital for the activity administered to the patient be correct. Many factors may influence the activity meter accuracy, such as the type of container, geometry, and radioactive material volume. The aim of this study was to analyze the measurements variations in 0.5 ml and 1.0 ml of "9"9"mTc pure and diluted in 2.5 ml of saline solution, in containers used in nuclear medicine. Variations of up to 4 % in measured values were found. (author)

  15. Methodology for using prompt gamma activation analysis to measure the binary diffusion coefficient of a gas in a porous medium

    International Nuclear Information System (INIS)

    Rios Perez, Carlos A.; Biegalski, Steve R.; Deinert, Mark R.

    2012-01-01

    Highlights: ► Prompt gamma activation analysis is used to study gas diffusion in a porous system. ► Diffusion coefficients are determined using prompt gamma activation analysis. ► Predictions concentrations fit experimental measurements with an R 2 of 0.98. - Abstract: Diffusion plays a critical role in determining the rate at which gases migrate through porous systems. Accurate estimates of diffusion coefficients are essential if gas transport is to be accurately modeled and better techniques are needed that can be used to measure these coefficients non-invasively. Here we present a novel method for using prompt gamma activation analysis to determine the binary diffusion coefficients of a gas in a porous system. Argon diffusion experiments were conducted in a 1 m long, 10 cm diameter, horizontal column packed with a SiO 2 sand. The temporal variation of argon concentration within the system was measured using prompt gamma activation analysis. The binary diffusion coefficient was obtained by comparing the experimental data with the predictions from a numerical model in which the diffusion coefficient was varied until the sum of square errors between experiment and model data was minimized. Predictions of argon concentration using the optimal diffusivity fit experimental measurements with an R 2 of 0.983.

  16. Thermodynamics of proton binding and weak (Cl−, Na+ and K+) species formation, and activity coefficients of 1,2-dimethyl-3-hydroxypyridin-4-one (deferiprone)

    International Nuclear Information System (INIS)

    Bretti, Clemente; Cigala, Rosalia Maria; Crea, Francesco; Lando, Gabriele; Sammartano, Silvio

    2014-01-01

    Graphical abstract: Trend of the deferiprone protonation constant (log K 1 H ) vs. ionic strength (in the molal concentration scale) in NaCl (□), KCl (Δ) and (CH 3 ) 4 NCl (○), at T = 298.15 K. - Highlights: • Thermodynamics, solubility and distribution of deferiprone in NaCl, KCl and (CH 3 ) 4 NCl. • Deferiprone total solubility is 0.100 mol · dm −3 in pure water and shows salting out. • The protonation process is entropic for the first step and enthalpic for the second. • Debye–Hückel, SIT and Pitzer approaches used for modelling of protonation constants. • Formation constants of three weak species were determined, Nadef, Kdef and H 2 defCl. - Abstract: The acid base properties of 1,2-dimethyl-3-hydroxypyridin-4-one (also known as deferiprone, def, figure 1), together with the solubility and the distribution ratio have been studied potentiometrically at different temperatures and ionic strengths in NaCl, KCl and in (CH 3 ) 4 NCl aqueous solutions. The total solubility of deferiprone is fairly high (0.100 mol · dm −3 in pure water) and decreases with increasing salt concentration (salting out effect); this behaviour is greater in NaCl than in (CH 3 ) 4 NCl aqueous solutions. From the analysis of the solubility and the distribution measurements it was possible to determine the Setschenow and the activity coefficients of the neutral species. Deferiprone shows two protonation steps, whose protonation constants are logK 1 H =10.088 and logK 2 H =3.656 at infinite dilution and T = 298.15 K. The ionic strength dependence of the protonation constants was interpreted both in terms of variation of the activity coefficients, using the Debye–Hückel, the SIT (Specific ion Interaction Theory) and the Pitzer approaches, or considering the formation of weak species with the ions of the supporting electrolyte (e.g. Na + , K + and Cl − ). Moreover, temperature gradients were provided for the two protonation constants. The stepwise protonation enthalpy

  17. A Cumulative Spore Killing Approach: Synergistic Sporicidal Activity of Dilute Peracetic Acid and Ethanol at Low pH Against Clostridium difficile and Bacillus subtilis Spores.

    Science.gov (United States)

    Nerandzic, Michelle M; Sankar C, Thriveen; Setlow, Peter; Donskey, Curtis J

    2016-01-01

    Background.  Alcohol-based hand sanitizers are the primary method of hand hygiene in healthcare settings, but they lack activity against bacterial spores produced by pathogens such as Clostridium difficile and Bacillus anthracis. We previously demonstrated that acidification of ethanol induced rapid sporicidal activity, resulting in ethanol formulations with pH 1.5-2 that were as effective as soap and water washing in reducing levels of C difficile spores on hands. We hypothesized that the addition of dilute peracetic acid (PAA) to acidified ethanol would enhance sporicidal activity while allowing elevation of the pH to a level likely to be well tolerated on skin (ie, >3). Methods.  We tested the efficacy of acidified ethanol solutions alone or in combination with PAA against C difficile and Bacillus subtilis spores in vitro and against nontoxigenic C difficile spores on hands of volunteers. Results.  Acidification of ethanol induced rapid sporicidal activity against C difficile and to a lesser extent B subtilis. The addition of dilute PAA to acidified ethanol resulted in synergistic enhancement of sporicidal activity in a dose-dependent fashion in vitro. On hands, the addition of 1200-2000 ppm PAA enhanced the effectiveness of acidified ethanol formulations, resulting in formulations with pH >3 that were as effective as soap and water washing. Conclusions.  Acidification and the addition of dilute PAA induced rapid sporicidal activity in ethanol. Our findings suggest that it may be feasible to develop effective sporicidal ethanol formulations that are safe and tolerable on skin.

  18. Determination of molybdate mean ionic activity coefficients for the assessment of radionuclide mobility

    International Nuclear Information System (INIS)

    Grambow, B.; Mueller, R.; Rother, A.

    1992-01-01

    Isopiestic tests at 25deg C and solubility tests as temperatures between 22 and 190deg C were used to determine solubility products and activity coefficients in the Nd-Na-Ca-Mg-Cl-MoO 4 -H 2 O system. Pitzer parameters were determined for the binary Na-MoO 4 -H 2 O and Mg-MoO 4 -H 2 O systems, the ternary Na-Cl-MoO 4 -H 2 O and the resiprocal Na-Mg-Cl-MoO 4 -H 2 O system. Solubility products K s0 were determined for MgMoO 4 x5H 2 O, CaMoO 4 x0.2H 2 O and Na 0.5 Nd 0.5 MoO 4 x0.16H 2 O; for the latter two phases the temperature dependence of solubility was determined. Isopiestic tests in concentrated binary and ternary systems with MoO 4 as a main component are consistent with solubility tests, in which MoO 4 is present only as trace component. (orig.)

  19. Comparison of diffusion coefficients and activation energies for AG diffusion in silicon carbide

    International Nuclear Information System (INIS)

    Kim, Bong Goo; Yeo, Sung Hwan; Lee, Young Woo; Cho, Moon Sung

    2015-01-01

    The migration of silver (Ag) in silicon carbide (SiC) and 110mAg through SiC of irradiated tri-structural isotropic (TRISO) fuel has been studied for the past three to four decades. However, there is no satisfactory explanation for the transport mechanism of Ag in SiC. In this work, the diffusion coefficients of Ag measured and/or estimated in previous studies were reviewed, and then pre-exponential factors and activation energies from the previous experiments were evaluated using Arrhenius equation. The activation energy is 247.4 kJ·mol -1 from Ag paste experiments between two SiC layers produced using fluidized-bed chemical vapor deposition (FBCVD), 125.3 kJ·mol -1 from integral release experiments (annealing of irradiated TRISO fuel), 121.8 kJ·mol -1 from fractional Ag release during irradiation of TRISO fuel in high flux reactor (HFR), and 274.8 kJ·mol -1 from Ag ion implantation experiments, respectively. The activation energy from ion implantation experiments is greater than that from Ag paste, fractional release and integral release, and the activation energy from Ag paste experiments is approximately two times greater than that from integral release experiments and fractional Ag release during the irradiation of TRISO fuel in HFR. The pre-exponential factors are also very different depending on the experimental methods and estimation. From a comparison of the pre-exponential factors and activation energies, it can be analogized that the diffusion mechanism of Ag using ion implantation experiment is different from other experiments, such as a Ag paste experiment, integral release experiments, and heating experiments after irradiating TRISO fuel in HFR. However, the results of this work do not support the long held assumption that Ag release from FBCVD-SiC, used for the coating layer in TRISO fuel, is dominated by grain boundary diffusion. In order to understand in detail the transport mechanism of Ag through the coating layer, FBCVD-SiC in TRISO fuel, a

  20. The nature of single-ion activity coefficients calculated from potentiometric measurements on cells with liquid junctions

    Energy Technology Data Exchange (ETDEWEB)

    Zarubin, Dmitri P., E-mail: dmitri.zarubin@mtu-net.ru [Department of Physical and Collod Chemistry, Moscow State University of Technology and Management, 73 Zemlyanoi Val, Moscow 109803 (Russian Federation)

    2011-08-15

    Highlights: > Problem of ionic activity coefficients, determined by potentiometry, is reconsidered. > They are found to be functions of mean activity coefficients and transport numbers of ions. > The finding is verified by calculations and comparing the results with reported data. > Calculations are performed for systems with single electrolytes and binary mixtures. - Abstract: Potentiometric measurements on cells with liquid junctions are sometimes used for calculations of single-ion activity coefficients in electrolyte solutions, the incidence of this being increased recently. As surmised by Guggenheim in the 1930s, such coefficients (of ions i), {gamma}{sub i}, are actually complicated functions of mean ionic activity coefficients, {gamma}{sub {+-}}, and transport numbers of ions, t{sub i}. In the present paper specific functions {gamma}{sub i}({gamma}{sub {+-}}, t{sub i}) are derived for a number of cell types with an arbitrary mixture of strong electrolytes in a one-component solvent in the liquid-junction system. The cell types include cells with (i) identical electrodes, (ii) dissimilar electrodes reversible to the same ions, (iii) dissimilar electrodes reversible to ions of opposite charge signs, (iv) dissimilar electrodes reversible to different ions of the same charge sign, and (v) identical reference electrodes and an ion-selective membrane permeable to ions of only one type. Pairs of functions for oppositely charged ions are found to be consistent with the mean ionic activity coefficients as would be expected for pairs of the proper {gamma}{sub i} quantities by definition of {gamma}{sub {+-}}. The functions are tested numerically on some of the reported {gamma}{sub i} datasets that are the more tractable. A generally good agreement is found with data reported for cells with single electrolytes HCl and KCl in solutions, and with binary mixtures in the liquid-junction systems of KCl from the reference solutions and NaCl and HCl from the test solutions. It

  1. On the calculation of single ion activity coefficients in homogeneous ionic systems by application of the grand canonical ensemble

    DEFF Research Database (Denmark)

    Sloth, Peter

    1993-01-01

    The grand canonical ensemble has been used to study the evaluation of single ion activity coefficients in homogeneous ionic fluids. In this work, the Coulombic interactions are truncated according to the minimum image approximation, and the ions are assumed to be placed in a structureless......, homogeneous dielectric continuum. Grand canonical ensemble Monte Carlo calculation results for two primitive model electrolyte solutions are presented. Also, a formula involving the second moments of the total correlation functions is derived from fluctuation theory, which applies for the derivatives...... of the individual ionic activity coefficients with respect to the total ionic concentration. This formula has previously been proposed on the basis of somewhat different considerations....

  2. Sorption kinetics of polycyclic aromatic hydrocarbons removal using granular activated carbon: Intraparticle diffusion coefficients

    International Nuclear Information System (INIS)

    Valderrama, C.; Gamisans, X.; Heras, X. de las; Farran, A.; Cortina, J.L.

    2008-01-01

    Granular activated carbon (GAC) was evaluated as a suitable sorbent for polycyclic aromatic hydrocarbons (PAHs) removal from aqueous solutions. For this purpose, kinetic measurements on the extraction of a family of six PAHs were taken. A morphology study was performed by means of a scanning electron microscopy (SEM) analysis of GAC samples. Analyses of the batch rate data for each PAH were carried out using two kinetic models: the homogenous particle diffusion model (HPDM) and the shell progressive model (SPM). The process was controlled by diffusion rate the solutes (PAHs) that penetrated the reacted layer at PAH concentrations in the range of 0.2-10 mg L -1 . The effective particle diffusion coefficients (D eff ) derived from the two models were determined from the batch rate data. The Weber and Morris intraparticle diffusion model made a double contribution to the surface and pore diffusivities in the sorption process. The D eff values derived from both the HPMD and SPM equations varied from 1.1 x 10 -13 to 6.0 x 10 -14 m 2 s -1 . The simplest model, the pore diffusion model, was applied first for data analysis. The model of the next level of complexity, the surface diffusion model, was applied in order to gain a deeper understanding of the diffusion process. This model is able to explain the data, and the apparent surface diffusivities are in the same order of magnitude as the values for the sorption of functionalized aromatic hydrocarbons (phenols and sulphonates) that are described in the literature

  3. Degradation of chitosan hydrogel dispersed in dilute carboxylic acids by solution plasma and evaluation of anticancer activity of degraded products

    Science.gov (United States)

    Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Theeramunkong, Sewan; Saito, Nagahiro

    2018-01-01

    Chitosan is a polysaccharide that has been extensively studied in the field of biomedicine, especially its water-soluble degraded products called chitooligosaccharides (COS). In this study, COS were produced by the degradation of chitosan hydrogel dispersed in a dilute solution (i.e., 1.55 mM) of various kinds of carboxylic acids using a non-thermal plasma technology called solution plasma (SP). The degradation rates of chitosan were influenced by the type of carboxylic acids, depending on the interaction between chitosan and each carboxylic acid. After SP treatment, the water-soluble degraded products containing COS could be easily separated from the water-insoluble residue of chitosan hydrogel by centrifugation. The production yields of the COS were mostly higher than 55%. Furthermore, the obtained COS products were evaluated for their inhibitory effect as well as their selectivity against human lung cancer cells (H460) and human lung normal cells (MRC-5).

  4. Molecular Descriptors Family on Structure Activity Relationships 6. Octanol-Water Partition Coefficient of Polychlorinated Biphenyls

    Directory of Open Access Journals (Sweden)

    Lorentz JÄNTSCHI

    2006-01-01

    Full Text Available Octanol-water partition coefficient of two hundred and six polychlorinated biphenyls was model by the use of an original method based on complex information obtained from compounds structure. The regression analysis shows that best results are obtained in four-varied model (r2 = 0.9168. The prediction ability of the model was studied through leave-one-out analysis (r2cv(loo = 0.9093 and in training and test sets analysis. Modeling the octanol-water partition coefficient of polychlorinated biphenyls by integration of complex structural information provide a stable and performing four-varied model, allowing us to make remarks about relationship between structure of polychlorinated biphenyls and associated octanol-water partition coefficients.

  5. Towards the Development of a Second-Order Approximation in Activity Coefficient Models Based on Group Contributions

    DEFF Research Database (Denmark)

    Abildskov, Jens; Constantinou, Leonidas; Gani, Rafiqul

    1996-01-01

    A simple modification of group contribution based models for estimation of liquid phase activity coefficients is proposed. The main feature of this modification is that contributions estimated from the present first-order groups in many instances are found insufficient since the first-order groups...... correlation/prediction capabilities, distinction between isomers and ability to overcome proximity effects....

  6. Phase Equilibria of Mixtures Containing Glycol and n-Alkane: Experimental Study of Infinite Dilution Activity Coefficients and Modeling Using the Cubic-Plus-Association Equation of State

    DEFF Research Database (Denmark)

    Afzal, Waheed; Breil, Martin Peter; Théveneau, Pascal

    2009-01-01

    previously reported in the literature, along with the data measured in this work have been modeled using the cubic-plus-association (CPA) equation of state (EoS). Satisfactory results have been obtained using temperature-independent interaction parameters. Useful remarks are presented about the application...

  7. Thermodynamic Calculation of the Distribution Coefficient Between the Liquid and Solid Phases of an Element in Dilute Solution in a Metal: Application to the Purification of Beryllium; Calcul Thermodynamique du Coefficient de Distribution Entre Phases Liquide et Solide d'un Element en Presence d'Autres Constituants en Solution Diluee dans un Metal: Application a la Purification du Beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Desre, P. [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie (France); Schaub, B. [Centre d' Etudes Nucleaires de Grenoble (France); Bonnier, I. E. [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie, Grenoble (France)

    1966-01-15

    The authors calculate the distribution coefficient {Gamma}{sub i} between the liquid and solid phases of an element i in the presence of other elements j in a solvent M ({Gamma}{sub i} = x'{sub i}/x{sub i}, where x'{sub i} and x{sub i} are the atomic fractions of i in the solid and liquid phases respectively) from the thermodynamic properties of binary systems of the type (i, M), (j, M) and (i, j). They show that the interaction of all the elements present may, under certain conditions, strongly affect the value of the coefficient {Gamma}{sub i}. This effect is pronounced if the following condition is fulfilled: {gamma}{sup {infinity}}{sub i(M)}, {gamma}{sup {infinity}}{sub j(M)} > {gamma}{sup {infinity}}{sub ij} where {gamma}{sup {infinity}}{sub i(M)}, {gamma}{sup {infinity}}{sub j(M)} and {gamma}{sup {infinity}}{sub ij} are limiting activity coefficients of the constituents i and j in the (i, M) (j, M) and (i, j) liquid state systems. It is a simple matter to deduce from this condition an application to the purification of metals by the zone-melting method; the condition enables one to choose an element j which is added deliberately to a metal in order to facilitate the elimination-of an element i (subsequent elimination of the element j being also, of course, a simple matter). For example, the authors were able to confirm that the addition of aluminium to beryllium enables one to improve the elimination of iron during the purification of the beryllium by the zone-melting technique, the aluminium acting as a carrier. (author) [French] Les auteurs calculent le coefficient de distribution Greek-Capital-Letter-Gamma {sub i} entre phases liquide et solide d'un element i en presence d'autres elements j dans un solvant M ( Greek-Capital-Letter-Gamma {sub i} = x'{sub i}/x{sub i}, x'{sub i} et x{sub i} representant respectivement les fractions atomiques de i dans les phases solide et liquide), a partir des proprietes thermodynamiques des systemes binaires de type: (i, M

  8. Characterization of the Major Odor-Active Compounds in the Leaves of the Curry Tree Bergera koenigii L. by Aroma Extract Dilution Analysis.

    Science.gov (United States)

    Steinhaus, Martin

    2015-04-29

    Curry leaves are a popular seasoning herb with a pronounced sulfury and burnt odor, the molecular background of which was yet unclear. Application of an aroma extract dilution analysis to the volatile fraction of curry leaves isolated by solvent extraction and solvent-assisted flavor evaporation afforded 23 odor-active compounds with flavor dilution (FD) factors ranging from 1 to 8192. On the basis of the comparison of their retention indices, mass spectra, and odor properties with data of reference compounds, the structures of 22 odorants could be assigned, 15 of which had not been reported in curry leaves before. Odorants with high FD factors included 1-phenylethanethiol (FD factor 8192), linalool (4096), α-pinene (2048), 1,8-cineole (1024), (3Z)-hex-3-enal (256), 3-(methylsulfanyl)propanal (128), myrcene (64), (3Z)-hex-3-en-1-ol (32), and (2E,6Z)-nona-2,6-dienal (32). The unique sulfury and burnt odor exhibited by 1-phenylethanethiol in combination with its high FD factor suggested that it constitutes the character impact compound of fresh curry leaf aroma.

  9. Activity coefficients of CaCl{sub 2} in (serine or proline + water) mixtures at T = 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Ma Jingjing [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Zhang Xinkuan [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); School of Chemistry and Chemical Engineering, Xinxiang University, Xinxiang, Henan 453003 (China); Zhuo Kelei, E-mail: lchow@mail.ucf.ed [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Liu Hongxun; Wang Jianji [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)

    2010-05-15

    Activity coefficients for the (CaCl{sub 2} + amino acid + water) system were determined at a temperature of 298.15 K using ion-selective electrodes. The range of molalities of CaCl{sub 2} is (0.01 to 0.20) mol . kg{sup -1}, and that of amino acids is (0.10 to 0.40) mol . kg{sup -1}. The activity coefficients obtained from the Debye-Hueckel extended equation and the Pitzer equation are in good agreement with each other. Results show that the interactions between CaCl{sub 2} and amino acid are controlled mainly by the electrostatic interactions (attraction). Gibbs free energy interaction parameters (g{sub EA}) and salting constants (k{sub S}) are positive, indicating that these amino acids are salted out by CaCl{sub 2}. These results are discussed based on group additivity model.

  10. Activity coefficients of CaCl{sub 2} in (maltose + water) and (lactose + water) mixtures at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Zhuo Kelei [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)], E-mail: klzhuo@263.net; Liu Hongxun; Zhang Honghao; Liu Yaohui; Wang Jianji [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)

    2008-05-15

    Activity coefficients of CaCl{sub 2} in disaccharide {l_brace}(maltose, lactose) + water{r_brace} mixtures at 298.15 K were determined by cell potentials. The molalities of CaCl{sub 2} ranged from about 0.01 mol . kg{sup -1} to 0.20 mol . kg{sup -1}, the mass fractions of maltose from 0.05 to 0.25, and those of lactose from 0.025 to 0.125. The cell potentials were analyzed by using the Debye-Hueckel extended equation and the Pitzer equation. The activity coefficients obtained from the two theoretical models are in good agreement with each other. Gibbs free energy interaction parameters (g{sub ES}) and salting constants (k{sub S}) were also obtained. These were discussed in terms of the stereo-chemistry of saccharide molecules and the structural interaction model.

  11. Activity coefficients of CaCl2 in (maltose + water) and (lactose + water) mixtures at 298.15 K

    International Nuclear Information System (INIS)

    Zhuo Kelei; Liu Hongxun; Zhang Honghao; Liu Yaohui; Wang Jianji

    2008-01-01

    Activity coefficients of CaCl 2 in disaccharide {(maltose, lactose) + water} mixtures at 298.15 K were determined by cell potentials. The molalities of CaCl 2 ranged from about 0.01 mol . kg -1 to 0.20 mol . kg -1 , the mass fractions of maltose from 0.05 to 0.25, and those of lactose from 0.025 to 0.125. The cell potentials were analyzed by using the Debye-Hueckel extended equation and the Pitzer equation. The activity coefficients obtained from the two theoretical models are in good agreement with each other. Gibbs free energy interaction parameters (g ES ) and salting constants (k S ) were also obtained. These were discussed in terms of the stereo-chemistry of saccharide molecules and the structural interaction model

  12. Determination of Diffusion Coefficients and Activation Energy of Selected Organic Liquids using Reversed-Flow Gas Chromatographic Technique

    International Nuclear Information System (INIS)

    Khalisanni Khalid; Rashid Atta Khan; Sharifuddin Mohd Zain

    2012-01-01

    Evaporation of vaporize organic liquid has ecological consequences when the compounds are introduced into both freshwater and marine environments through industrial effluents, or introduced directly into the air from industrial unit processes such as bioreactors and cooling towers. In such cases, a rapid and simple method are needed to measure physicochemical properties of the organic liquids. The Reversed-Flow Gas Chromatography (RF-GC) sampling technique is an easy, fast and accurate procedure. It was used to measure the diffusion coefficients of vapors from liquid into a carrier gas and at the same time to determine the rate coefficients for the evaporation of the respective liquid. The mathematical expression describing the elution curves of the samples peaks was derived and used to calculate the respective parameters for the selected liquid pollutants selected such as methanol, ethanol, 1-propanol, 1-butanol, n-pentane, n-hexane, n-heptane and n-hexadecane, evaporating into the carrier gas of nitrogen. The values of diffusion coefficients found were compared with those calculated theoretically or reported in the literature. The values of evaporation rate were used to determine the activation energy of respective samples using Arrhenius equation. An interesting finding of this work is by using an alternative mathematical analysis based on equilibrium at the liquid-gas interphase, the comparison leads to profound agreement between theoretical values of diffusion coefficients and experimental evidence. (author)

  13. Activity coefficients of NaF in (glucose+water) and (sucrose+water) mixtures at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Luis, Felipe [Departamento de Quimica Fisica, Universidad de La Laguna, Tenerife (Spain)]. E-mail: ffhelu@ull.es; Galleguillos, Hector R. [Departamento de Ingenieria Quimica, Universidad de Antofagasta, Antofagasta (Chile); Vazquez, Mario V. [Instituto de Quimica, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellin (Colombia)

    2004-11-01

    The activity coefficients of NaF in (glucose+water) and (sucrose+water) mixtures were experimentally determined at 298.15 K from electromotive force measurements of the following electrochemical cell containing two ion selective electrodes (ISEs):Na-ISE|NaF(m),sugar(Y),H2O(100-Y)|F-ISEThe molality (m) varied between ca. 0.01 mol.kg{sup -1} and saturation, while the mass fractions of sugar in the mixture (Y) were 0, 0.10, 0.20, 0.30 and 0.40. The values for electromotive force were analyzed using different models for describing the variations of the activity coefficients with concentration, including an extended Debye-Huckel, the Pitzer and the Scatchard equations. Results obtained with the different models were in good agreement. Once E{sup -}bar was determined, the mean coefficients of ionic activity for NaF, the free energy of transference from the water to the (sugar+water) mixture, and the primary NaF hydration number were calculated. The variation of these magnitudes with the composition of the mixture is comparative discussed in terms of the ion-solvent and ion-ion interactions with results from the literature for NaCl in (glucose+water) and (sucrose+water) systems.

  14. Verification of key odorants in rose oil by gas chromatography-olfactometry/aroma extract dilution analysis, odour activity value and aroma recombination.

    Science.gov (United States)

    Xiao, Zuobing; Li, Jing; Niu, Yunwei; Liu, Qiang; Liu, Junhua

    2017-10-01

    Rose oil is much too expensive but very popular. It's well known that the flower oil's aroma profile hasn't been intensively investigated. In order to verify the aroma profile of rose oil, the synthetic blend of odorants was prepared and then compared with the original rose oil using electronic nose analysis (ENA) combined with quantitative descriptive analysis (QDA). The odorants from rose oils were screened out by Gas Chromatography-Olfactometry/aroma extract dilution analysis (GC-O/AEDA) combined with odour activity value (OAV). Both ENA and QDA indicated the recombination model derived from OAV and GC-O/AEDA closely resembled the original rose oil. The experiment results show that rose oxide, linalool, α-pinene, β-pinene, nonanal, heptanal citronellal, phenyl ethyl alcohol, benzyl alcohol, eugenol, methyl eugenol, β-citronellol, hexyl acetate, β-ionone, nerol, etc. are very important constituent to rose oil aroma profile.

  15. Influence of extragent dilution upon light rare earths separation

    International Nuclear Information System (INIS)

    Korpusova, R.D.; Smirnova, N.N.

    1978-01-01

    The effect of diluting the extragent on separation of REE in the presence of 6 g-equiv. of LiNO 3 has been studied. For experiments use was made of TBP diluted with kerosene or butylbenzene (40,50,70 vol.%). The separation coefficients have been determined under conditions of saturation. The content of trace amounts of the components has been determined by the weight method; the content of macroimpurities - by the radiometric method. It has been established that the coefficient of Ce-La, Pr-La separation is not affected by the dilution of the extragent. The only exception is the Pr 142 -La pair; in the presence of trace amounts of better extracted element and two-fold dilution the separation coefficient increases almost by 150%. For the Pr-Ce pair the effect of dilution is better noticeable in that case when more extracted element is present in trace amounts. However, a comparison of the effect of dilution on separation coefficients of all REE pairs under study has shown that this effect is the strongest for the samarium-neodymium pair. The data obtained allow an assumption to be made that kerosene, as a diluent, affects the steric factor and coordination. Therefore, upon dilution the coefficient of the samarium-neodymium pair separation is affected most of all

  16. Characterization of the major odor-active compounds in Thai durian ( Durio zibethinus L. 'Monthong') by aroma extract dilution analysis and headspace gas chromatography-olfactometry.

    Science.gov (United States)

    Li, Jia-Xiao; Schieberle, Peter; Steinhaus, Martin

    2012-11-14

    An aroma extract dilution analysis applied on the volatile fraction isolated from Thai durian by solvent extraction and solvent-assisted flavor evaporation resulted in 44 odor-active compounds in the flavor dilution (FD) factor range of 1-16384, 41 of which could be identified and 24 that had not been reported in durian before. High FD factors were found for ethyl (2S)-2-methylbutanoate (fruity; FD 16384), ethyl cinnamate (honey; FD 4096), and 1-(ethylsulfanyl)ethanethiol (roasted onion; FD 1024), followed by 1-(ethyldisulfanyl)-1-(ethylsulfanyl)ethane (sulfury, onion), 2(5)-ethyl-4-hydroxy-5(2)-methylfuran-3(2H)-one (caramel), 3-hydroxy-4,5-dimethylfuran-2(5H)-one (soup seasoning), ethyl 2-methylpropanoate (fruity), ethyl butanoate (fruity), 3-methylbut-2-ene-1-thiol (skunky), ethane-1,1-dithiol (sulfury, durian), 1-(methylsulfanyl)ethanethiol (roasted onion), 1-(ethylsulfanyl)propane-1-thiol (roasted onion), and 4-hydroxy-2,5-dimethylfuran-3(2H)-one (caramel). Among the highly volatile compounds screened by static headspace gas chromatography-olfactometry, hydrogen sulfide (rotten egg), acetaldehyde (fresh, fruity), methanethiol (rotten, cabbage), ethanethiol (rotten, onion), and propane-1-thiol (rotten, durian) were found as additional potent odor-active compounds. Fourteen of the 41 characterized durian odorants showed an alkane-1,1-dithiol, 1-(alkylsulfanyl)alkane-1-thiol, or 1,1-bis(alkylsulfanyl)alkane structure derived from acetaldehyde, propanal, hydrogen sulfide, and alkane-1-thiols. Among these, 1-(propylsulfanyl)ethanethiol, 1-{[1-(methylsulfanyl)ethyl]sulfanyl}ethanethiol, and 1-{[1-(ethylsulfanyl)ethyl]sulfanyl}ethanethiol were reported for the first time in a natural product.

  17. Thermodynamics of electrolytes. III. Activity and osmotic coefficients for 2-2 electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Pitzer, K.S.; Mayorga, G.

    1974-01-01

    The peculiar behavior of 2-2 and higher valence type electrolytes is discussed in terms of various theories some of which assume, while others do not, an equilibrium between separated ions and ion pairs as distinct chemical species. It is recognized that in some cases a distinct species of inner-shell ion pairs is indicated by spectroscopic or ultrasonic data. Nevertheless, there are many advantages in representing, if possible, the properties of these electrolytes by appropriate virial coefficients and without chemical association equilibria. It is shown that this is possible and is conveniently accomplished by the addition of these equations are given for nine solutes. It is also noted that these equations have been successfully applied to mixed electrolytes involving one component of the 2-2 type. 2 figures, 1 table.

  18. revue bibliographique des représentations analytiques de coefficients d'activité ioniques moyens dans les solutions binaires électrolytiques Bibliographic Review of Analytic Equations of Mean Lonic Activity Coefficients in Electrolytic Binary Solutions

    Directory of Open Access Journals (Sweden)

    Cruz J. -L.

    2006-11-01

    Full Text Available Le calcul de certaines propriétés à l'équilibre, de systèmes électrolytiques, nécessite la connaissance des coefficients d'activité en phase liquide des constituants de ces systèmes. L'estimation du coefficient d'activité ionique moyen de l'électrolyte permet, pour des systèmes binaires, de calculer ces coefficients d'activité. Dans cette revue bibliographique sont présentées les principales expressions analytiques, de coefficients d'activité ioniques moyens, fournies par la littérature. II est possible de classer ces expressions en plusieurs grandes catégories en fonction des modèles dont elles dérivent. Des critères de choix, de l'une ou l'autre de ces équations, sont proposés suivant le type de système électrolytique et le domaine de concentration étudiés. Liquid-phase activity coefficients must be known in order to calculate various equilibrium properties of electrolytic systems. For binary systems, these coefficients can be calculated by estimating the mean ionic activity coefficient of the electrolyte. This bibliographic review describes the principal analytic equations for mean ionic activity coefficients found in the literature. These equations can be classified in several major categories according to the theoretical model from which they are derived. Some criteria are proposed for choosing one or another of these equations on the basis of the type of electrolytic system and the concentration range studied.

  19. Interaction Studies of Dilute Aqueous Oxalic Acid

    Directory of Open Access Journals (Sweden)

    Kiran Kandpal

    2007-01-01

    Full Text Available Molecular conductance λm, relative viscosity and density of oxalicacid at different concentration in dilute aqueous solution were measured at 293 K.The conductance data were used to calculate the value association constant.Viscosity and density data were used to calculate the A and B coefficient ofJone-Dole equation and apparent molar volume respectively. The viscosityresults were utilized for the applicability of Modified Jone-Dole equation andStaurdinger equations. Mono oxalate anion acts, as structure maker and thesolute-solvent interaction were present in the dilute aqueous oxalic acid.

  20. Measurement of gas/water uptake coefficients for trace gases active in the marine environment

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, P. (Boston Coll., Chestnut Hill, MA (United States). Dept. of Chemistry); Worsnop, D.W.; Zahniser, M.S.; Kolb, C.E. (Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics)

    1992-02-01

    Ocean produced reduced sulfur compounds including dimethylsulfide (DMS), hydrogen sulfide (H{sub 2}S), carbon disulfide (CS{sub 2}), methyl mercaptan (CH{sub 3}CH) and carbonyl sulfide (OCS) deliver a sulfur burden to the atmosphere which is roughly equal to sulfur oxides produced by fossil fuel combustion. These species and their oxidation products dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO{sub 2}) and methane sulfonic acid (MSA) dominate aerosol and CCN production in clean marine air. Furthermore, oxidation of reduced sulfur species will be strongly influenced by NO{sub x}/O{sub 3} chemistry in marine atmospheres. The multiphase chemical processes for these species must be understood in order to study the evolving role of combustion produced sulfur oxides over the oceans. We have measured the chemical and physical parameters affecting the uptake of reduced sulfur compounds, their oxidation products, ozone, and nitrogen oxides by the ocean's surface, and marine clouds, fogs, and aerosols. These parameters include: gas/surface mass accommodation coefficients; physical and chemically modified (effective) Henry's law constants; and surface and liquid phase reaction constants. These parameters are critical to understanding both the interaction of gaseous trace species with cloud and fog droplets and the deposition of trace gaseous species to dew covered, fresh water and marine surfaces.

  1. Antimicrobial Activity of Ephedra pachyclada Methanol Extract on Some Enteric Gram Negative Bacteria Which Causes Nosocomial Infections by Agar Dilution Method

    Directory of Open Access Journals (Sweden)

    Amin Sadeghi Dosari

    2016-10-01

    Full Text Available Background Past history indicates that plants were served as an important source of medicine. Otherwise, in developing countries people use medicinal plants against infectious disease because they cannot afford expensive drugs. Due to increasing rate of drug-resistant diseases, there is an urgent need to detect novel antimicrobial compounds from medicinal plants. Objectives The aim of the present study was to determine Antimicrobial activity of Ephedra pachyclada methanol extract on some enteric Gram-negative bacteria which causes nosocomial infections by agar dilution method. Methods In this cross-sectional study, in order to examine the antimicrobial effects of Ephedra pachyclada extract on intestinal Gram-negative bacteria, we exposed them to 0/128, 0/25, 0/5, 1, 2, 4 and 8 mg/mL of the extract. Ephedra pachyclada was collected from Jiroft Heights and methanolic extract was prepared with maceration method, during which, 50 gr powder of Ephedra pachyclada was dissolved in 300 mL of 80% methanol. Results In this study, the antibacterial effects of Ephedra pachyclada extract on Gram-negative bacteria such as Pseudomonas aeruginosa, Escherichia coli (PTCC-O157, Escherichia coli (ATCC-25922, Klebsiella pnemoniae, Serratia marcescens was investigated, defining the minimum inhibitory concentration (MIC by agar dilution method. It has been demonstrated that methanolic extract of Ephedra pachyclada affect intestinal Gram-negative bacteria. Conclusions The result showed that, Ephedra pachyclada extract has effective antimicrobial ingredients which are cheap and readily available. It can be used for medicinal purposes in the production of antimicrobial drug.

  2. Measurement of the activity coefficient of carbon in steels in liquid sodium

    International Nuclear Information System (INIS)

    Surville, G.

    1983-06-01

    In sodium cooled fast reactors carbon is both a carbon impurity and element of structural materials. Carbon transfert through liquid sodium can produce carburization or decarburization of structural materials. Carbon content in sodium is determined with thin foils of austenitic alloys, when equilibrium is reached thermodynamic activity of carbon in sodium is deduced from carbon activity in alloys. Studied alloys are FeMn 20%, FeNi 30%, Z2CN 18-10 and Z3CND17-13. Carbon activity of alloys in sodium was between 5.10 -3 and 10 -1 at 600 and 650 0 C. Calibration was obtained with the alloys FeNi 30% in gaseous mixtures He-CO-CO 2 of known activity [fr

  3. Activity coefficients in (hydrogen chloride+holmium chloride) (aq) from T=(278.15 to 328.15) K

    International Nuclear Information System (INIS)

    Roy, Rabindra N.; Roy, Lakshmi N.; Tabor, Bennett J.; Richards, Sarah J.; Cummins, Mason P.; Himes, Curtis A.; Gibbs, Stephanie N.; Christiansen, Edward B.

    2005-01-01

    Activity coefficients of HCl in (hydrogen chloride+holmium chloride) (aq) have been calculated from the observed e.m.f.s using the Nernst equation. The temperatures ranged from (278.15 to 328.15) K at 5 K intervals and at constant total ionic strengths of (0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, and 1.5) mol.kg -1 . Electromotive-force measurements were made on the cell without liquid junction of the type:Pt vertical bar H 2 (g,p=101.325kPa) vertical bar HCl(m A ),HoCl 3 (m B ) vertical bar AgCl(s), vertical bar Ag(s) The results of the activity coefficients of HCl for this mixed electrolyte mixture have been interpreted in terms of the simpler Harned's equations and the ion-interaction model of Pitzer. Results show that the quadratic term is sufficient for the full range of Y B (the ionic strength fraction of the salt) to 0.9 at all the ionic strengths studied. The Pitzer's mixing parameters S θH,Ho and Ψ H,Ho,Cl (including higher order electrostatic effects) and θ H,Ho and Ψ H,Ho,Cl (excluding higher order electrostatic effects) have been determined. These values at T=298.15 K are: S θH , Ho =0.115, Ψ H,Ho,Cl =-.071; and θ H,Ho =-.663, Ψ H,Ho,Cl =0.165. The parameters obtained in this study reproduce the activity coefficients of HCl in the mixtures within 0.015 over the entire range of ionic strengths and within 0.009 for I>=0.05 mol.kg -1 over the entire temperature range

  4. Measurement of O(6)-alkylguanine-DNA alkyltransferase activity in tumour cells using stable isotope dilution HPLC-ESI-MS/MS.

    Science.gov (United States)

    Sun, Guohui; Zhao, Lijiao; Fan, Tengjiao; Ren, Ting; Zhong, Rugang

    2016-10-15

    The repair of DNA mediated by O(6)-alkylguanine-DNA alkyltransferase (AGT) provides protection against DNA damage from endogenous or exogenous alkylation of the O(6) position of guanine. However, this repair acts as a double-edged sword in cancer treatment, as it not only protects normal cells from chemotherapy-associated toxicities, but also results in cancer cell resistance to guanine O(6)-alkylating antitumour agents. Thus, AGT plays an important role in predicting the individual susceptibility to guanine O(6)-alkylating carcinogens and chemotherapies. Accordingly, it is necessary to establish a quantitative method for determining AGT activity with high accuracy, sensitivity and practicality. Here, we describe a novel nonradioactive method for measuring AGT activity using stable isotope dilution high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). This method is based on the irreversibility of the removal of the O(6)-alkyl group from guanine by AGT and on the high affinity of O(6)-benzylguanine (O(6)-BG) as an AGT substrate. HPLC-ESI-MS/MS was used to measure the AGT activities in cell protein extracts from eight tumour lines, demonstrating that AGT activity was quite variable among different cell lines, ranging from nondetectable to 1021 fmol/mg protein. The experiments performed in intact tumour cells yielded similar results but exhibited slightly higher activities than those observed in cell protein extracts. The accuracy of this method was confirmed by an examination of AGT expression levels using western blotting analysis. To our knowledge, this method is the first mass spectrometry-based AGT activity assay, and will likely provide assistance in the screening of cancer risk or the application of chemotherapies. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Dynamic Coefficients of a Tilting Pad With Active Lubrication: Comparison Between Theoretical and Experimental Results

    DEFF Research Database (Denmark)

    Cerda Varela, Alejandro Javier; Santos, Ilmar

    2015-01-01

    experimental results from the literature for industrial grade passive tilting pad bearings. This initial validation is followed by a comparison with experimental identification results obtained from a test rig featuring the active bearing design. Good overall agreement is observed in both configurations...

  6. Hybridizing pines with diluted pollen

    Science.gov (United States)

    Robert Z. Callaham

    1967-01-01

    Diluted pollens would have many uses by the tree breeder. Dilutions would be particularly advantageous in making many controlled pollinations with a limited amount of pollen. They also would be useful in artificial mass pollinations of orchards or single trees. Diluted pollens might help overcome troublesome genetic barriers to crossing. Feasibility o,f using diluted...

  7. Characterization of the aroma-active compounds in pink guava (Psidium guajava, L.) by application of the aroma extract dilution analysis.

    Science.gov (United States)

    Steinhaus, Martin; Sinuco, Diana; Polster, Johannes; Osorio, Coralia; Schieberle, Peter

    2008-06-11

    The volatiles present in fresh, pink-fleshed Colombian guavas ( Psidium guajava, L.), variety regional rojo, were carefully isolated by solvent extraction followed by solvent-assisted flavor evaporation, and the aroma-active areas in the gas chromatogram were screened by application of the aroma extract dilution analysis. The results of the identification experiments in combination with the FD factors revealed 4-methoxy-2,5-dimethyl-3(2 H)-furanone, 4-hydroxy-2,5-dimethyl-3(2 H)-furanone, 3-sulfanylhexyl acetate, and 3-sulfanyl-1-hexanol followed by 3-hydroxy-4,5-dimethyl-2(5 H)-furanone, ( Z)-3-hexenal, trans-4,5-epoxy-( E)-2-decenal, cinnamyl alcohol, ethyl butanoate, hexanal, methional, and cinnamyl acetate as important aroma contributors. Enantioselective gas chromatography revealed an enantiomeric distribution close to the racemate in 3-sulfanylhexyl acetate as well as in 3-sulfanyl-1-hexanol. In addition, two fruity smelling diastereomeric methyl 2-hydroxy-3-methylpentanoates were identified as the ( R,S)- and the ( S,S)-isomers, whereas the ( S,R)- and ( R,R)-isomers were absent. Seven odorants were identified for the first time in guavas, among them 3-sulfanylhexyl acetate, 3-sulfanyl-1-hexanol, 3-hydroxy-4,5-dimethyl-2(5 H)-furanone, trans-4,5-epoxy-( E)-2-decenal, and methional were the most odor-active.

  8. Synthesis and characterization of vanadium doped SnO2 diluted magnetic semiconductor nanoparticles with enhanced photocatalytic activities

    International Nuclear Information System (INIS)

    Mazloom, J.; Ghodsi, F.E.; Golmojdeh, H.

    2015-01-01

    Highlights: • Pure and V-doped SnO 2 nanoparticles were synthesized using a facile sol–gel route. • The V 4+ ions were incorporated into the SnO 2 lattice and located at the Sn 4+ sites. • TEM images reveled that by increasing the doping content, average grain size decreased. • We show that the V-doped SnO 2 is more photoactive than undoped SnO 2 . • The V-doped SnO 2 nanoparticles exhibited ferromagnetism at room temperature. - Abstract: Vanadium doped SnO 2 nanoparticles were synthesized by a facile sol–gel method. Different analytical techniques including TG/DTG, XRD, XPS, VSM and PL were used to investigate the influence of dopant concentration on structural, morphological, compositional, magnetic and optical properties of prepared nanoparticles. The XRD study showed a dominant tetragonal structure. The X-ray photoelectron spectroscopy proved the presence of vanadium as V 4+ species. TEM image revealed that particle size decrease by doping. It was found that room temperature ferromagnetic (RTFM) behavior is strongly dependent on vanadium dopant content and the magnetic saturation dropped rapidly with increasing V content, which can be explained reasonably through bound magnetic polaron (BMP) model. A quenching in green luminescence intensity was observed in V-doped SnO 2 compared to undoped sample. The 5% V-doped SnO 2 sample showed better photocatalytic activity than undoped one in decomposing methylene blue and rhodamine B

  9. Helium dilution refrigerator

    International Nuclear Information System (INIS)

    1973-01-01

    A new system of continuous heat exchange for a helium dilution refrigerator is proposed. The 3 He effluent tube is concurrent with the affluent mixed helium tube in a vertical downward direction. Heat exchange efficiency is enhanced by placing in series a number of elements with an enlarged surface area

  10. Isotope dilution analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fudge, A.

    1978-12-15

    The following aspects of isotope dilution analysis are covered in this report: fundamental aspects of the technique; elements of interest in the nuclear field, choice and standardization of spike nuclide; pre-treatment to achieve isotopic exchange and chemical separation; sensitivity; selectivity; and accuracy.

  11. Quantitation using a stable isotope dilution assay (SIDA) and thresholds of taste-active pyroglutamyl decapeptide ethyl esters (PGDPEs) in sake.

    Science.gov (United States)

    Hashizume, Katsumi; Ito, Toshiko; Igarashi, Shinya

    2017-03-01

    A stable isotope dilution assay (SIDA) for two taste-active pyroglutamyl decapeptide ethyl esters (PGDPE1; (pGlu)LFGPNVNPWCOOC 2 H 5 , PGDPE2; (pGlu)LFNPSTNPWCOOC 2 H 5 ) in sake was developed using deuterated isotopes and high-resolution mass spectrometry. Recognition thresholds of PGDPEs in sake were estimated as 3.8 μg/L for PGDPE1 and 8.1 μg/L for PGDPE2, evaluated using 11 student panelists aged in their twenties. Quantitated concentrations in 18 commercial sake samples ranged from 0 to 27 μg/L for PGDPE1 and from 0 to 202 μg/L for PGDPE2. The maximum levels of PGDPE1 and PGDPE2 in the sake samples were approximately 8 and 25 times higher than the estimated recognition thresholds, respectively. The results indicated that PGDPEs may play significant sensory roles in the sake. The level of PGDPEs in unpasteurized sake samples decreased during storage for 50 days at 6 °C, suggesting PGDPEs may be enzymatically decomposed.

  12. Estimation of abraham solvation equation coefficients for hydrogen bond formation from abraham solvation parameters for solute activity and basicity

    NARCIS (Netherlands)

    Noort, van P.C.M.

    2013-01-01

    Abraham solvation equations find widespread use in environmental chemistry and pharmaco-chemistry. The coefficients in these equations, which are solvent (system) descriptors, are usually determined by fitting experimental data. To simplify the determination of these coefficients in Abraham

  13. Gas/aerosol Partitioning Parameterisation For Global Modelling: A Physical Interpretation of The Relationship Between Activity Coefficients and Relative Humidity

    Science.gov (United States)

    Metzger, S.; Dentener, F. J.; Lelieveld, J.; Pandis, S. N.

    A computationally efficient model (EQSAM) to calculate gas/aerosol partitioning ofsemi-volatile inorganic aerosol components has been developed for use in global- atmospheric chemistry and climate models; presented at the EGS 2001.We introduce and discuss here the physics behind the parameterisation, upon whichthe EQuilib- rium Simplified Aerosol Model EQSAM is based. The parameterisation,which ap- proximates the activity coefficient calculation sufficiently accurately forglobal mod- elling, is based on a method that directly relates aerosol activitycoefficients to the ambient relative humidity, assuming chemical equilibrium.It therefore provides an interesting alternative for the computationally expensiveiterative activity coefficient calculation methods presently used in thermodynamicgas/aerosol equilibrium mod- els (EQMs). The parameterisation can be used,however, also in dynamical models that calculate mass transfer between theliquid/solid aerosol phases and the gas/phase explicitly; dynamical models oftenincorporate an EQM to calculate the aerosol com- position. The gain of theparameterisation is that the entire system of the gas/aerosol equilibrium partitioningcan be solved non-iteratively, a substantial advantage in global modelling.Since we have already demonstrated at the EGS 2001 that EQSAM yields similarresults as current state-of-the-art equilibrium models, we focus here on a dis- cussionof our physical interpretation of the parameterisation; the identification of theparameters needed is crucial. Given the lag of reliable data, the best way tothor- oughly validate the parameterisation for global modelling applications is theimple- mentation in current state-of-the-art gas/aerosol partitioning routines, whichare embe- ded in e.g. a global atmospheric chemistry transport model, by comparingthe results of the parameterisation against the ones based on the widely used activitycoefficient calculation methods (i.e. Bromley, Kussik-Meissner or Pitzer). Then

  14. Activity coefficients in (hydrogen chloride+holmium chloride) (aq) from T=(278.15 to 328.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Rabindra N. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States)]. E-mail: rroy@drury.edu; Roy, Lakshmi N. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Tabor, Bennett J. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Richards, Sarah J. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Cummins, Mason P. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Himes, Curtis A. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Gibbs, Stephanie N. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Christiansen, Edward B. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States)

    2005-07-15

    Activity coefficients of HCl in (hydrogen chloride+holmium chloride) (aq) have been calculated from the observed e.m.f.s using the Nernst equation. The temperatures ranged from (278.15 to 328.15) K at 5 K intervals and at constant total ionic strengths of (0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, and 1.5) mol.kg{sup -1}. Electromotive-force measurements were made on the cell without liquid junction of the type:Pt vertical bar H{sub 2}(g,p=101.325kPa) vertical bar HCl(m{sub A}),HoCl{sub 3}(m{sub B}) vertical bar AgCl(s), vertical bar Ag(s) The results of the activity coefficients of HCl for this mixed electrolyte mixture have been interpreted in terms of the simpler Harned's equations and the ion-interaction model of Pitzer. Results show that the quadratic term is sufficient for the full range of Y{sub B} (the ionic strength fraction of the salt) to 0.9 at all the ionic strengths studied. The Pitzer's mixing parameters S{sub {theta}}{sub H,Ho} and {psi}{sub H,Ho,Cl} (including higher order electrostatic effects) and {theta}{sub H,Ho} and {psi}{sub H,Ho,Cl} (excluding higher order electrostatic effects) have been determined. These values at T=298.15 K are: S{sub {theta}}{sub H},{sub Ho}=0.115, {psi}{sub H,Ho,Cl}=-.071; and {theta}{sub H,Ho}=-.663, {psi}{sub H,Ho,Cl}=0.165. The parameters obtained in this study reproduce the activity coefficients of HCl in the mixtures within 0.015 over the entire range of ionic strengths and within 0.009 for I>=0.05 mol.kg{sup -1} over the entire temperature range.

  15. Isopiestic determination of the activity coefficients of some aqueous rare earth electrolyte solutions at 250C. I. The rare earth chlorides

    International Nuclear Information System (INIS)

    Spedding, F.H.; Weber, H.O.; Saeger, V.W.; Petheram, H.H.; Rard, J.A.; Habenschuss, A.

    1976-01-01

    The osmotic coefficients of the aqueous trichlorides of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y were determined from 0.1 M to saturation at 25 0 C. Semiempirical least-squares equations were obtained for the osmotic coefficients as a function of molality and these equations were used to calculate water activities and mean molal activity coefficients. The water activities of the light rare earth chlorides at constant molalities are higher than for the heavy rare earths, while the mean molal activity coefficients are larger for the heavy rare earths than for the light ones. The above effects are discussed in terms of changes in the cationic radii and hydration of the rare earth ions

  16. Effect of Silicon on Activity Coefficients of Platinum in Liquid Fe-Si, With Application to Core Formation

    Science.gov (United States)

    Righter, K.; Pando, K.; Danielson, L. R.; Humayun, M.

    2017-01-01

    Earth's core contains approximately 10% of a light element that is likely a combination of S, C, Si, and O, with Si possibly being the most abundant light element. Si dissolved into Fe liquids can have a large effect on the magnitude of the activity coefficient of siderophile elements (SE) in Fe liquids, and thus the partitioning behavior of those elements between core and mantle. The effect of Si can be small such as for Ni and Co, or large such as for Mo, Ge, Sb, As. The effect of Si on many siderophile elements is unknown yet could be an important, and as yet unquantified, influence on the core-mantle partitioning of SE. Here we report new experiments designed to quantify the effect of Si on the partitioning of Pt (with Re and Ru in progress or planned) between metal and silicate melt. The results will be applied to Earth, for which we have excellent constraints on the mantle Pt concentrations.

  17. [Evaluation of in vitro antimicrobial activity of cefazolin alone and in combination with cefmetazole or flomoxef using agar dilution method and disk diffusion method].

    Science.gov (United States)

    Matsuo, K; Uete, T

    1992-10-01

    Antimicrobial activities of cefazolin (CEZ) against 251 strains of various clinical isolates obtained during 1989 and 1990 were determined using the Mueller-Hinton agar dilution method at an inoculum level 10(6) CFU/ml. The reliability of the disk susceptility test was also studied using Mueller-Hinton agar and various disks at inoculum levels of 10(3-4) CFU/cm2 in estimating approximate values of MICs. In addition, antimicrobial activities of CEZ and cefmetazole (CMZ) or flomoxef (FMOX) in combination were investigated against methicillin-sensitive and -resistant Staphylococcus aureus (MSSA and MRSA) using the checkerboard agar dilution MIC method and the disk diffusion test either with the disks contained CEZ, CMZ, and FMOX alone, or CEZ, and CMZ or FMOX in combination. In this study, the MICs of CEZ against S. aureus were distributed with the 3 peak values at 0.39 microgram/ml, 3.13 micrograms/ml and > 100 micrograms/ml. MICs against MSSA were 0.39 microgram/ml to 0.78 microgram/ml, whereas those against MRSA were greater than 0.78 microgram/ml. MICs against majority of strains of Enterococcus faecalis were 25 micrograms/ml. Over 90% of strains of Escherichia coli and Klebsiella pneumoniae were inhibited at the level of 3.13 micrograms/ml. About 60% of isolates of indole negative Proteus spp. were inhibited at the levels of less than 3.13 micrograms/ml and 100% at 6.25 micrograms/ml, but MICs against indole positive Proteus spp., Serratia spp. and Pseudomonas aeruginosa were over 100 micrograms/ml. The antimicrobial activities of CEZ against these clinical isolates were not significantly different compared to those reported about 15-20 years ago, except for S. aureus. Highly resistant strains of S. aureus to CEZ were more prevalent in this study. The inhibitory zones obtained with the disk test were compared with MICs. The results of CEZ disk susceptibility test with 30 micrograms disk (Showa) or 10 micrograms disk (prepared in this laboratory) were well

  18. Defects in dilute nitrides

    International Nuclear Information System (INIS)

    Chen, W.M.; Buyanova, I.A.; Tu, C.W.; Yonezu, H.

    2005-01-01

    We provide a brief review our recent results from optically detected magnetic resonance studies of grown-in non-radiative defects in dilute nitrides, i.e. Ga(In)NAs and Ga(Al,In)NP. Defect complexes involving intrinsic defects such as As Ga antisites and Ga i self interstitials were positively identified.Effects of growth conditions, chemical compositions and post-growth treatments on formation of the defects are closely examined. These grown-in defects are shown to play an important role in non-radiative carrier recombination and thus in degrading optical quality of the alloys, harmful to performance of potential optoelectronic and photonic devices based on these dilute nitrides. (author)

  19. Assessment of odor activity value coefficient and odor contribution based on binary interaction effects in waste disposal plant

    Science.gov (United States)

    Wu, Chuandong; Liu, Jiemin; Yan, Luchun; Chen, Haiying; Shao, Huiqi; Meng, Tian

    2015-02-01

    Odor activity value (OAV) has been widely used for the assessment of odor pollution from various sources. However, little attention has been paid to the extreme OAV variation and potential inaccuracies of odor contribution assessment caused by odor interaction effects. The objective of this study is to assess the odor interaction effect for precise assessment of odor contribution. In this paper, samples were collected from a food waste disposal plant, and analyzed by instrumental and olfactory method to conclude odorants' occurrence and OAV. Then odor activity value coefficient (γ) was first proposed to evaluate the type and the level of binary interaction effects based on determination of OAV variation. By multiplying OAV and γ, odor activity factor (OAF) was used to reflect the real OAV. Correlation between the sum of OAF and odor concentration reached 80.0 ± 5.7%, which was 10 times higher than the sum of OAV used before. Results showed that hydrogen sulfide contributed most (annual average 66.4 ± 15.8%) to odor pollution in the waste disposal plant. However, as odor intensity of samples in summer rising, odor contribution of trimethylamine increased to 48.3 ± 3.7% by the strong synergistic interaction effect, while odor contribution of phenol decreased to 0.1 ± 0.02% for the increasing antagonistic interaction effect.

  20. Gluconeogenesis from labeled carbon: estimating isotope dilution

    International Nuclear Information System (INIS)

    Kelleher, J.K.

    1986-01-01

    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

  1. The Diet Quality of Competitive Adolescent Male Rugby Union Players with Energy Balance Estimated Using Different Physical Activity Coefficients

    Directory of Open Access Journals (Sweden)

    Tracy Burrows

    2016-09-01

    Full Text Available Objectives: The aims of the current study were to comprehensively assess the dietary intakes and diet quality of a sample of Australian competitive adolescent rugby union players and compare these intakes with National and Sports Dietitians Association (SDA Recommendations for adolescent athletes. A secondary aim investigated applying different physical activity level (PAL coefficients to determine total energy expenditure (TEE in order to more effectively evaluate the adequacy of energy intakes. Design: Cross-sectional. Methods: Anthropometrics and dietary intakes were assessed in 25 competitive adolescent male rugby union players (14 to 18 years old. Diet was assessed using the validated Australian Eating Survey (AES food frequency questionnaire and diet quality was assessed through the Australian Recommended Food Score. Results: The median dietary intakes of participants met national recommendations for percent energy (% E from carbohydrate, protein and total fat, but not carbohydrate intake when evaluated as g/day as proposed in SDA guidelines. Median intakes of fibre and micronutrients including calcium and iron also met national recommendations. Overall diet quality was classified as ‘good’ with a median diet quality score of 34 (out of a possible 73; however, there was a lack of variety within key food groups including carbohydrates and proteins. Non-core food consumption exceeded recommended levels at 38% of the daily total energy intake, with substantial contributions from takeaway foods and sweetened beverages. A PAL coefficient of 1.2–1.4 was found to best balance the energy intakes of these players in their pre-season. Conclusions: Adolescent rugby players met the percent energy recommendations for macronutrients and attained an overall ‘good’ diet quality score. However, it was identified that when compared to specific recommendations for athletes, carbohydrate intakes were below recommendations and these players in their

  2. Disposal of Low-Activity Liquid Effluents by Dilution; Elimination par Dilution d'Effluents Liquides Faiblement Radioactifs; 0423 0414 0410 041b 0414 ; Eliminacion de Efluentes Liquidos de Baja Radiactividad por Dilucion

    Energy Technology Data Exchange (ETDEWEB)

    Bovard, P.; Candillon, C. [Service de Controle des Radiations et de Genie Radioactif, Commissariat a l' Energie Atomique, Saclay (France)

    1960-07-01

    From the results already obtained in France by monitoring radioactivity in the neighbourhood of nuclear plant, some conclusions may be drawn regarding the choice of disposal procedures. I. Results obtained In 1957 we started a progressive study of the effect exerted by nuclear plant. In order to establish the proportion due to the nuclear centres, the study comprises determination of the levels of natural radioactivity and artificial contamination. Examples related to reference areas are quoted. The greater part of artificial radioactivity is apparently due to radioactive fall-out; this is not surprising, considering the quantities of radioactive isotopes disposed of in France to date. Some laboratory tests have been made. These have helped to determine certain mechanisms, have increased our knowledge of site pollution, and have enabled us to improve our sampling methods. II. Laboratory tests These were concerned with 1. adsorption phenomena similar to those occurring in rivers and streams in the course of effluent dilution: fixation on finely-divided minerals, e.g. mica and quartz. Radioisotopes such as Sr{sup 9}'0, Cs{sup 137} and Y{sup 90} appear to behave very differently: under average disposal conditions Sr{sup 90} seems to be the least adsorbed; 2. soil and plant contamination, utilizing columns and cubes of soil in situ. We found it necessary to standardize our samples so as to facilitate further analysis and make the results comparable. III. Site selection and ways and means of disposal From this group of still incomplete results and studies we are attempting to educe certain principles to govern site selection. Once the site has been chosen, the experience gained enables natural conditions to be turned to account. (author) [French] Des resultats deja fournis par la surveillance en France, de la radioactivite aux alentours des installations nucleaires, il est possible de tirer certains enseignements quant au choix des processus de rejet. I. Resultats

  3. Osmotic and activity coefficients of aqueous NaTcO4 and NaReO4 solutions at 250C

    International Nuclear Information System (INIS)

    Boyd, G.E.

    1978-01-01

    Isopiestic vapor-pressure comparison experiments were performed with aqueous binary sodium perchlorate, pertechnetate, and perrhenate solutions to concentrations of approximately 8.5 m. Osmotic coefficients for these solutions and mean molal ionic activity coefficients for NaTcO 4 and NaReO 4 were derived from the isotonic molalities. Pitzer's treatment was applied to describe the concentration dependence of the osmotic coefficients of NaClO 4 , NaTcO 4 , and NaReO 4 , and the implications of the parameters derived from a least-squares fit are discussed in terms of solvent structure and interionic forces. 4 tables, 1 figure

  4. Vapour pressures, osmotic and activity coefficients for binary mixtures containing (1-ethylpyridinium ethylsulfate + several alcohols) at T = 323.15 K

    International Nuclear Information System (INIS)

    Calvar, Noelia; Gomez, Elena; Dominguez, Angeles; Macedo, Eugenia A.

    2010-01-01

    Osmotic coefficients of binary mixtures containing several primary and secondary alcohols (1-propanol, 2-propanol, 1-butanol, 2-butanol, and 1-pentanol) and the pyridinium-based ionic liquid 1-ethylpyridinium ethylsulfate were determined at T = 323.15 K using the vapour pressure osmometry technique. From the experimental results, vapour pressure and activity coefficients can be determined. For the correlation of osmotic coefficients, the extended Pitzer model modified by Archer, and the modified NRTL (MNRTL) model were used, obtaining deviations lower than 0.017 and 0.047, respectively. The mean molal activity coefficients and the excess Gibbs free energy for the binary mixtures studied were determined from the parameters obtained with the extended Pitzer model modified by Archer.

  5. EXAFS of dilute systems: fluorescence detection

    International Nuclear Information System (INIS)

    Hastings, J.B.

    1979-01-01

    Since the first observations of the variation of the absorption coefficient for x-rays above the energy thresholds in the thirties until the early seventies, measurements and analysis of these variations were merely intended for the understanding of the underlying physics. Recently, with the understanding of the information available about the local atomic structure in the neighborhood of the absorbing species and the availability of high intensity synchrotron radiation sources, EXAFS has become a powerful structural tool. In these discussions, the details of the measurements for very dilute species are presented. It is shown that for the more dilute systems the measurement of the emission rather than the direct absorption is a more favorable technique

  6. The dependence of activity coefficient on intensive thermodynamic parameters in a liquid Fe-N-V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hutny, A.; Siwka, J. [Faculty of Materials Processing Technology and Applied Physics, Technical Univ. of Czestochowa (Poland)

    2003-07-01

    The article presents the methodology and results of experimental studies on the solubility of nitrogen in liquid Fe-V alloys. Tests were carried out using the levitation metal melting technique. Liquid alloys of Fe-V ([%V]{sub wt.%} 1.5; 2.5; 4,0; 5.8; 7.8; 12.2; 45%) were saturated with nitrogen at temperatures of 2073, 2173, 2273 K. The partial pressure of nitrogen was varied in the range 0.001-2.5 MPa. The experiment involved melting a 1 g specimen in an electromagnetic field generated by a levitation coil, filling the reaction chamber with nitrogen up to the required pressure and heating the specimen up to a preset temperature. High nitrogen concentrations were obtained in the samples due to the formation of high nitrogen partial pressures in the gaseous phase in the reaction chamber. In such conditions, all interactions of nitrogen in the alloy tested could be disclosed, namely: nitrogen-vanadium, nitrogen-nitrogen, and nitrogen-nitrogen-vanadium interactions. The results of the tests showed a nonlinear dependence of the activity coefficient, f{sub N}, not only on vanadium content in the alloy, but also on nitrogen content in it. Using the experimental data and the findings of the previous study on the liquid Fe-N alloy, temperature relationships of inter- and self-reaction parameters have been determined. (orig.)

  7. Vapor pressures, osmotic and activity coefficients for (LiBr + acetonitrile) between the temperatures (298.15 and 343.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Nasirzadeh, Karamat E-mail: karamat.nasirzadeh@chemie.uni-regensburg.de; Neueder, Roland; Kunz, Werner

    2004-06-01

    Precise vapor pressure data for pure acetonitrile and (LiBr + acetonitrile) are given for temperatures ranging from T=(298.15 to 343.15) K. The molality range is from m=(0.0579 to 0.8298) mol {center_dot} kg{sup -1}. The osmotic coefficients are calculated by taking into account the second virial coefficient of acetonitrile. The parameters of the extended Pitzer ion interaction model of Archer and the mole fraction-based thermodynamic model of Clegg-Pitzer are evaluated. These models accurately reproduce the available osmotic coefficients. The parameters of the extended Pitzer ion interaction model of Archer are used to calculate the mean molal activity coefficients.

  8. Quantifying the Presence and Activity of Aerobic, Vinyl Chloride-Degrading Microorganisms in Dilute Groundwater Plumes by Using Real-Time PCR

    Science.gov (United States)

    2013-07-01

    nested PCR experiment with etnC primers. The initial PCRs were carried out with environmental DNA and the primers NVC105 and NVC106 (72). Then, 2 μl...natural attenuation, dilute VC plumes Acknowledgements We would like to thank Bill Richard (EST Associates, Inc.), Tim McDougall (OASIS Environmental...these steps, the DNA extraction protocol was carried out as recommended by MoBio. Additional experimentation led us to further refine the Sterivex

  9. Improved models for the prediction of activity coefficients in nearly athermal mixtures: Part I. Empirical modifications of free-volume models

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios M.; Coutsikos, Philipos; Tassios, Dimitrios

    1994-01-01

    Mixtures containing exclusively normal, branched and cyclic alkanes, as well as saturated hydrocarbon polymers (e.g. poly(ethylene) and poly(isobutylene)), are known to exhibit almost athermal behavior. Several new activity coefficient models containing both combinatorial and free-volume contribu......Mixtures containing exclusively normal, branched and cyclic alkanes, as well as saturated hydrocarbon polymers (e.g. poly(ethylene) and poly(isobutylene)), are known to exhibit almost athermal behavior. Several new activity coefficient models containing both combinatorial and free...

  10. Single-dilution enzyme-linked immunosorbent assay for quantification of antigen-specific salmonid antibody

    Science.gov (United States)

    Alcorn, S.W.; Pascho, R.J.

    2000-01-01

    An enzyme-linked immunosorbent assay (ELISA) was developed on the basis of testing a single dilution of serum to quantify the level of antibody to the p57 protein of Renibaclerium salmoninarum in sockeye salmon (Oncorhynchus nerka). The levels of antibody were interpolated from a standard curve constructed by relating the optical densities (OD) produced by several dilutions of a high-titer rainbow trout (O. mykiss) antiserum to the p57 protein. The ELISA OD values produced by as many as 36 test sera on each microplate were compared with the standard curve to calculate the antigen-specific antibody activity. Repeated measurements of 36 samples on 3 microplates on each of 6 assay dates indicated that the mean intraassay coefficient of variation (CV) was 6.68% (range, 0-23%) and the mean interassay CV was 8.29% (range, 4-16%). The antibody levels determined for the serum sample from 24 sockeye salmon vaccinated with a recombinant p57 protein generally were correlated with the levels determined by endpoint titration (r2 = 0.936) and with results from another ELISA that was based on extrapolation of antibody levels from a standard curve (r2 = 0.956). The single-dilution antibody ELISA described here increases the number of samples that can be tested on each microplate compared with immunoassays based on analysis of several dilutions of each test serum. It includes controls for interassay standardization and can be used to test fish weighing <3 g.

  11. Prediction of time-integrated activity coefficients in PRRT using simulated dynamic PET and a pharmacokinetic model.

    Science.gov (United States)

    Hardiansyah, Deni; Attarwala, Ali Asgar; Kletting, Peter; Mottaghy, Felix M; Glatting, Gerhard

    2017-10-01

    To investigate the accuracy of predicted time-integrated activity coefficients (TIACs) in peptide-receptor radionuclide therapy (PRRT) using simulated dynamic PET data and a physiologically based pharmacokinetic (PBPK) model. PBPK parameters were estimated using biokinetic data of 15 patients after injection of (152±15)MBq of 111 In-DTPAOC (total peptide amount (5.78±0.25)nmol). True mathematical phantoms of patients (MPPs) were the PBPK model with the estimated parameters. Dynamic PET measurements were simulated as being done after bolus injection of 150MBq 68 Ga-DOTATATE using the true MPPs. Dynamic PET scans around 35min p.i. (P 1 ), 4h p.i. (P 2 ) and the combination of P 1 and P 2 (P 3 ) were simulated. Each measurement was simulated with four frames of 5min each and 2 bed positions. PBPK parameters were fitted to the PET data to derive the PET-predicted MPPs. Therapy was simulated assuming an infusion of 5.1GBq of 90 Y-DOTATATE over 30min in both true and PET-predicted MPPs. TIACs of simulated therapy were calculated, true MPPs (true TIACs) and predicted MPPs (predicted TIACs) followed by the calculation of variabilities v. For P 1 and P 2 the population variabilities of kidneys, liver and spleen were acceptable (v10%). Treatment planning of PRRT based on dynamic PET data seems possible for the kidneys, liver and spleen using a PBPK model and patient specific information. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  12. Activity coefficients, interfacial tensions and retention in reversed-phase liquid chormatography on LiChrosorb RP-18 with methanol-water mixtures

    NARCIS (Netherlands)

    Hammers, W.E.; Meurs, G.J.; Ligny, C.L. de

    1982-01-01

    Literature data on activity coefficients of various solutes in water, of some tetraalkyl compounds in methanol-water mixture and of water in organic solvents have been correlated with the product of the molecular surface area of the solute and the solute-solvent interfacial tension at ambient

  13. Feasibility of Influencing the Dynamic Fluid Film Coefficients of a Multirecess Journal Bearing by means of Active Hybrid Lubrication

    DEFF Research Database (Denmark)

    Santos, Ilmar; Watanabe, F. Y.

    2003-01-01

    and control techniques. The feasibility of influencing the dynamic fluid film coefficients (stiffness and damping) by means of a controllable fluid injection into opposed bearing recesses is investigated. By controlling the pressure and flow injection using servo control systems, it is possible to obtain...

  14. Osmotic and activity coefficients of {y Na2SO4 + (1 - y) ZnSO4}(aq) at T = 298.15 K

    International Nuclear Information System (INIS)

    Marjanovic, V.; Ninkovic, R.; Miladinovic, J.; Todorovic, M.; Pavicevic, V.

    2005-01-01

    The osmotic coefficients of the mixed electrolyte solution {y Na 2 SO 4 + (1 - y) ZnSO 4 }(aq) have been measured by the isopiestic method, at T = 298.5 K. The experimental results were treated by Scatchard's, Pitzer-Kim's and Clegg-Pitzer-Brimblecombe's methods for mixed-electrolyte solutions. By these methods, the activity coefficients for Na 2 SO 4 and ZnSO 4 were calculated and compared. The Scatchard interaction parameters are used for calculation of the excess Gibbs free energy as a function of ionic strength and ionic-strength fraction of Na 2 SO 4 . Also, the Zdanovskii's rule of linearity is tested

  15. A unified view of energetic efficiency in active drag reduction, thrust generation and self-propulsion through a loss coefficient with some applications

    Science.gov (United States)

    Arakeri, Jaywant H.; Shukla, Ratnesh K.

    2013-08-01

    An analysis of the energy budget for the general case of a body translating in a stationary fluid under the action of an external force is used to define a power loss coefficient. This universal definition of power loss coefficient gives a measure of the energy lost in the wake of the translating body and, in general, is applicable to a variety of flow configurations including active drag reduction, self-propulsion and thrust generation. The utility of the power loss coefficient is demonstrated on a model bluff body flow problem concerning a two-dimensional elliptical cylinder in a uniform cross-flow. The upper and lower boundaries of the elliptic cylinder undergo continuous motion due to a prescribed reflectionally symmetric constant tangential surface velocity. It is shown that a decrease in drag resulting from an increase in the strength of tangential surface velocity leads to an initial reduction and eventual rise in the power loss coefficient. A maximum in energetic efficiency is attained for a drag reducing tangential surface velocity which minimizes the power loss coefficient. The effect of the tangential surface velocity on drag reduction and self-propulsion of both bluff and streamlined bodies is explored through a variation in the thickness ratio (ratio of the minor and major axes) of the elliptical cylinders.

  16. Gas-particle partitioning of semi-volatile organics on organic aerosols using a predictive activity coefficient model: analysis of the effects of parameter choices on model performance

    Science.gov (United States)

    Chandramouli, Bharadwaj; Jang, Myoseon; Kamens, Richard M.

    The partitioning of a diverse set of semivolatile organic compounds (SOCs) on a variety of organic aerosols was studied using smog chamber experimental data. Existing data on the partitioning of SOCs on aerosols from wood combustion, diesel combustion, and the α-pinene-O 3 reaction was augmented by carrying out smog chamber partitioning experiments on aerosols from meat cooking, and catalyzed and uncatalyzed gasoline engine exhaust. Model compositions for aerosols from meat cooking and gasoline combustion emissions were used to calculate activity coefficients for the SOCs in the organic aerosols and the Pankow absorptive gas/particle partitioning model was used to calculate the partitioning coefficient Kp and quantitate the predictive improvements of using the activity coefficient. The slope of the log K p vs. log p L0 correlation for partitioning on aerosols from meat cooking improved from -0.81 to -0.94 after incorporation of activity coefficients iγ om. A stepwise regression analysis of the partitioning model revealed that for the data set used in this study, partitioning predictions on α-pinene-O 3 secondary aerosol and wood combustion aerosol showed statistically significant improvement after incorporation of iγ om, which can be attributed to their overall polarity. The partitioning model was sensitive to changes in aerosol composition when updated compositions for α-pinene-O 3 aerosol and wood combustion aerosol were used. The octanol-air partitioning coefficient's ( KOA) effectiveness as a partitioning correlator over a variety of aerosol types was evaluated. The slope of the log K p- log K OA correlation was not constant over the aerosol types and SOCs used in the study and the use of KOA for partitioning correlations can potentially lead to significant deviations, especially for polar aerosols.

  17. Characterization of the major aroma-active compounds in mango (Mangifera indica L.) cultivars Haden, White Alfonso, Praya Sowoy, Royal Special, and Malindi by application of a comparative aroma extract dilution analysis.

    Science.gov (United States)

    Munafo, John P; Didzbalis, John; Schnell, Raymond J; Schieberle, Peter; Steinhaus, Martin

    2014-05-21

    The aroma-active compounds present in tree-ripened fruits of the five mango (Mangifera indica L.) cultivars Haden, White Alfonso, Praya Sowoy, Royal Special, and Malindi were isolated by solvent extraction followed by solvent-assisted flavor evaporation (SAFE) and analyzed by gas chromatography-olfactometery (GC-O). Application of a comparative aroma extract dilution analysis (cAEDA) afforded 54 aroma-active compounds in the flavor dilution (FD) factor range from 4 to ≥2048, 16 of which are reported for the first time in mango. The results of the identification experiments in combination with the FD factors revealed 4-hydroxy-2,5-dimethyl-3(2H)-furanone as an important aroma compound in all cultivars analyzed. Twenty-seven aroma-active compounds were present in at least one mango cultivar at an FD factor ≥128. Clear differences in the FD factors of these odorants between each of the mango cultivars suggested that they contributed to the unique sensory profiles of the individual cultivars.

  18. Oxygen exchange at gas/oxide interfaces: how the apparent activation energy of the surface exchange coefficient depends on the kinetic regime.

    Science.gov (United States)

    Fielitz, Peter; Borchardt, Günter

    2016-08-10

    In the dedicated literature the oxygen surface exchange coefficient KO and the equilibrium oxygen exchange rate [Fraktur R] are considered to be directly proportional to each other regardless of the experimental circumstances. Recent experimental observations, however, contradict the consequences of this assumption. Most surprising is the finding that the apparent activation energy of KO depends dramatically on the kinetic regime in which it has been determined, i.e. surface exchange controlled vs. mixed or diffusion controlled. This work demonstrates how the diffusion boundary condition at the gas/solid interface inevitably entails a correlation between the oxygen surface exchange coefficient KO and the oxygen self-diffusion coefficient DO in the bulk ("on top" of the correlation between KO and [Fraktur R] for the pure surface exchange regime). The model can thus quantitatively explain the range of apparent activation energies measured in the different regimes: in the surface exchange regime the apparent activation energy only contains the contribution of the equilibrium exchange rate, whereas in the mixed or in the diffusion controlled regime the contribution of the oxygen self-diffusivity has also to be taken into account, which may yield significantly higher apparent activation energies and simultaneously quantifies the correlation KO ∝ DO(1/2) observed for a large number of oxides in the mixed or diffusion controlled regime, respectively.

  19. Determination of self-absorption coefficient in measurement of solid sample activity using 4π ionization chamber

    International Nuclear Information System (INIS)

    Dryak, P.

    1982-01-01

    Computation based on the Monte Carlo method was tested for a 4π cylindrical ionization chamber with a detection volume of 7 litres, filled with argon. The sources are placed in the geometrical centre. The correction coefficient for self-absorption was determined as being the ratio of ionization currents induced by a source of finite size and by a massless point source. A flowchart of the program is given. The computations were experimentally tested for cylindrical sources of aqueous 137 Cs and 57 Co solutions. (M.D.)

  20. Activity coefficients of plutonium and cerium in liquid gallium at 1073 K: Application to a molten salt/solvent metal separation concept

    International Nuclear Information System (INIS)

    Lambertin, David; Ched'homme, Severine; Bourges, Gilles; Sanchez, Sylvie; Picard, Gerard S.

    2005-01-01

    Activity coefficients in liquid metal and salt phases are important parameters for predicting the separation efficiency of reductive extraction or electrochemical pyrochemical processes. The electrochemical properties of Ce and Pu in gallium metal and chlorides media - CaCl 2 and equimolar NaCl-KCl - have been studied at 1073 K. Cyclic voltammetry and chronoamperometry show the thermodynamic feasibility of using gallium as solvent metal for pyrochemical processes involving Pu and Ce. The activity coefficient of Pu in liquid Ga (log(γ Pu,Ga ) = -7.3 ± 0.5) is deduced from the results and is a basis of assessing the potential for using liquid metals in pyrochemical separation of actinides and lanthanides. Evaluation of literature data for Al, Bi and Cd suggests that Ga is most favorable for selective separation of Pu from Ce near 1073 K

  1. A thermodynamic model for solid solutions and its application to the C-Fe-Co, C-Fe-Ni and Mn-Cr-Pt solid dilutions

    International Nuclear Information System (INIS)

    Tao, D.P.

    2004-01-01

    Based on the free volume theory and the lattice model, the partition functions of pure solids and their mixtures were expressed. This resulted in the establishment of a thermodynamic model for solid solutions. The model naturally combines the excess entropy and excess enthalpy of a solution by means of new expressions of the configurational partition functions of solids and their mixtures derived from statistical thermodynamics, which is approximate to real solid solutions, that is S E ≠0 (V E ≠0) and H E ≠0. It can describe the thermodynamic properties of partially miscible systems and predict the thermodynamic properties in a multicomponent solid solution system using only the related binary infinite dilute activity coefficients. The predicted activity coefficients from the model are in good agreement with the experimental data of the ternary solid dilutions. This shows that the prediction effect of the proposed model is of better stability and reliability because it has a good physical basis

  2. Histogram analysis parameters of apparent diffusion coefficient reflect tumor cellularity and proliferation activity in head and neck squamous cell carcinoma.

    Science.gov (United States)

    Surov, Alexey; Meyer, Hans Jonas; Winter, Karsten; Richter, Cindy; Hoehn, Anna-Kathrin

    2018-05-04

    Our purpose was to analyze associations between apparent diffusion coefficient (ADC) histogram analysis parameters and histopathologicalfeatures in head and neck squamous cell carcinoma (HNSCC). The study involved 32 patients with primary HNSCC. For every tumor, the following histogram analysis parameters were calculated: ADCmean, ADCmax, ADC min , ADC median , ADC mode , P10, P25, P75, P90, kurtosis, skewness, and entropy. Furthermore, proliferation index KI 67, cell count, total and average nucleic areas were estimated. Spearman's correlation coefficient (p) was used to analyze associations between investigated parameters. In overall sample, all ADC values showed moderate inverse correlations with KI 67. All ADC values except ADCmax correlated inversely with tumor cellularity. Slightly correlations were identified between total/average nucleic area and ADC mean , ADC min , ADC median , and P25. In G1/2 tumors, only ADCmode correlated well with Ki67. No statistically significant correlations between ADC parameters and cellularity were found. In G3 tumors, Ki 67 correlated with all ADC parameters except ADCmode. Cell count correlated well with all ADC parameters except ADCmax. Total nucleic area correlated inversely with ADC mean , ADC min , ADC median , P25, and P90. ADC histogram parameters reflect proliferation potential and cellularity in HNSCC. The associations between histopathology and imaging depend on tumor grading.

  3. Consideration of the loss of activity in the soil for large transfer coefficients in the food chain

    International Nuclear Information System (INIS)

    Brenk, H.D.; Vogt, K.J.

    1978-01-01

    The studies have shown that in the case of large transfer coefficients there will result a considerable overestimation of the ingestion dose if nonradioactive depletion effects are neglected. This overestimation may, depending on nuclide, vegetation and transfer coefficient, amount to two orders of magnitude. There will result e.g. for the bone exposure of a grown-up person, caused by 90 Sr taken up by the consumption of root vegetables, a dose overestimation up to a factor of 50. For the dose to the kidneys of adults by 137 Cs through consumption of beef there will result an overestimation by a factor of up to 60. And for 129 I there will be obtained an infant thyroid dose from the pasture-cow-milk pathway being too large by a factor of up to 100. In order to be able to cover these cases by a sufficiently generalized formalism, too, it appears necessary therefore to modify or extend the 'Allgemeine Berechnungsgrundlagen' (German reg. guide for evaluating the exposure from environmental contamination) in the manner proposed in the paper. (orig./HP) 891 HP/orig.- 892 MB [de

  4. Mean activity coefficient measurement and thermodynamic modelling of the ternary mixed electrolyte (MgCl_2 + glucose + water) system at T = 298.15 K

    International Nuclear Information System (INIS)

    Rouhi, Azam; Bagherinia, Mohammad Ali

    2015-01-01

    Highlights: • The main goal of the work is to provide precise thermodynamic data for the system. • The method used was potentiometric method. • Pitzer ion interaction model and modified TCPC model were used. • The mass fractions of glucose were (0, 10, 20, 30 and 40)%. • The ionic strengths were from 0.0010 to 6.0000 mol · kg"−"1. - Abstract: In this work, the mean activity coefficients of MgCl_2 in pure water and (glucose + water) mixture solvent were determined using a galvanic cell without liquid junction potential of type: (Mg"2"+ + ISE)|MgCl_2 (m), glucose (wt.%), H_2O (100 wt.%)|AgCl|Ag. The measurements were performed at T = 298.15 K. Total ionic strengths were from (0.0010 to 6.0000) mol · kg"−"1. The various (glucose + water) mixed solvents contained (0, 10, 20, 30 and 40)% mass fractions percentage of glucose respectively. The mean activity coefficients measured were correlated with Pitzer ion interaction model and the Pitzer adjustable parameters were determined. Then these parameters were used to calculate the thermodynamics properties for under investigated system. The results showed that Pitzer ion interaction model can satisfactory describe the investigated system. The modified three-characteristic-parameter correlation (TCPC) model was applied to correlate the experimental activity coefficient data for under investigation electrolyte system, too.

  5. Effect of the reference solution in the measurement of ion activity coefficients using cells with transference at T = 298.15 K

    International Nuclear Information System (INIS)

    Lladosa, Estela; Arce, Alberto; Wilczek-Vera, Grazyna; Vera, Juan H.

    2010-01-01

    This work reports individual activity coefficients of ions at T = 298.15 K in aqueous solutions obtained from voltage values of the respective half-cell ion-selective-electrode and a single-junction Ag-AgCl reference electrode, filled with different reference solutions at different concentrations. For potassium and chloride ions in KCl aqueous solutions, reference solutions of KCl, NaCl, or CsCl were used. For sodium and chloride ions in aqueous NaCl solutions, reference solutions of CsCl were used. Experimental runs were performed at molalities (1, 2, and 3) m of the reference solution. The concentration of the sample solution was increased, starting from around 1 . 10 -3 m, up to the molality of the reference solution. The values of activity coefficients are calculated using the Henderson equation to estimate the liquid-junction potential. Results show that the ionic activity coefficients are independent of the nature and concentration of reference solution.

  6. Determination of the Thermodynamic Properties of Poly [2-(3-phenyl-3-methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] at Infinite Dilution by Inverse Gas Chromatography

    OpenAIRE

    KAYA, İsmet

    2014-01-01

    Some thermodynamic quantities were obtained for the interactions of poly [2-(3-phenyl -3- methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] Poly (PCHEMA-co-MA) with alcohols, ketones, acetates, aromatics and n-alkanes by inverse gas chromatography in the temperature range of 150-180oC. The specific retention volumes, Vgo, weight fraction activity coefficients of solute probes at infinite dilution, W1\\infty and Flory-Huggins thermodynamic interaction parameters, c12...

  7. Efficacy Coefficients Determined Using Nail Permeability and Antifungal Activity in Keratin-Containing Media Are Useful for Predicting Clinical Efficacies of Topical Drugs for Onychomycosis.

    Directory of Open Access Journals (Sweden)

    Yoshiki Matsuda

    Full Text Available Onychomycosis is difficult to treat topically due to the deep location of the infection under the densely keratinized nail plate. In order to obtain an in vitro index that is relevant to the clinical efficacy of topical anti-onychomycosis drugs, we profiled five topical drugs: amorolfine, ciclopirox, efinaconazole, luliconazole, and terbinafine, for their nail permeabilities, keratin affinities, and anti-dermatophytic activities in the presence of keratin. Efinaconazole and ciclopirox permeated full-thickness human nails more deeply than luliconazole. Amorolfine and terbinafine did not show any detectable permeation. The free-drug concentration of efinaconazole in a 5% human nail keratin suspension was 24.9%, which was significantly higher than those of the other drugs (1.1-3.9%. Additionally, efinaconazole was released from human nail keratin at a greater proportion than the other drugs. The MICs of the five drugs for Trichophyton rubrum were determined at various concentrations of keratin (0-20% in RPMI 1640 medium. The MICs of ciclopirox were not affected by keratin, whereas those of efinaconazole were slightly increased and those of luliconazole and terbinafine were markedly increased in the presence of 20% keratin. Efficacy coefficients were calculated using the nail permeation flux and MIC in media without or with keratin. Efinaconazole showed the highest efficacy coefficient, which was determined using MIC in media with keratin. The order of efficacy coefficients determined using MIC in keratin-containing media rather than keratin-free media was consistent with that of complete cure rates in previously reported clinical trials. The present study revealed that efficacy coefficients determined using MIC in keratin-containing media are useful for predicting the clinical efficacies of topical drugs. In order to be more effective, topical drugs have to possess higher efficacy coefficients.

  8. The Atmospherically Important Reaction of Hydroxyl Radicals with Methyl Nitrate: A Theoretical Study Involving the Calculation of Reaction Mechanisms, Enthalpies, Activation Energies, and Rate Coefficients.

    Science.gov (United States)

    Ng, Maggie; Mok, Daniel K W; Lee, Edmond P F; Dyke, John M

    2017-09-07

    A theoretical study, involving the calculation of reaction enthalpies, activation energies, mechanisms, and rate coefficients, was made of the reaction of hydroxyl radicals with methyl nitrate, an important process for methyl nitrate removal in the earth's atmosphere. Four reaction channels were considered: formation of H 2 O + CH 2 ONO 2 , CH 3 OOH + NO 2 , CH 3 OH + NO 3 , and CH 3 O + HNO 3 . For all channels, geometry optimization and frequency calculations were performed at the M06-2X/6-31+G** level, while relative energies were improved at the UCCSD(T*)-F12/CBS level. The major channel is found to be the H abstraction channel, to give the products H 2 O + CH 2 ONO 2 . The reaction enthalpy (ΔH 298 K RX ) of this channel is computed as -17.90 kcal mol -1 . Although the other reaction channels are also exothermic, their reaction barriers are high (>24 kcal mol -1 ), and therefore these reactions do not contribute to the overall rate coefficient in the temperature range considered (200-400 K). Pathways via three transition states were identified for the H abstraction channel. Rate coefficients were calculated for these pathways at various levels of variational transition state theory including tunneling. The results obtained are used to distinguish between two sets of experimental rate coefficients, measured in the temperature range of 200-400 K, one of which is approximately an order of magnitude greater than the other. This comparison, as well as the temperature dependence of the computed rate coefficients, shows that the lower experimental values are favored. The implications of the results to atmospheric chemistry are discussed.

  9. Diffusion coefficients of paracetamol in aqueous solutions

    International Nuclear Information System (INIS)

    Ribeiro, Ana C.F.; Barros, Marisa C.F.; Veríssimo, Luís M.P.; Santos, Cecilia I.A.V.; Cabral, Ana M.T.D.P.V.; Gaspar, Gualter D.; Esteso, Miguel A.

    2012-01-01

    Highlights: ► Mutual diffusion coefficients of paracetamol in aqueous dilute solutions. ► Influence of the thermodynamic factors on the variation of their mutual diffusion coefficients. ► Estimation of the mutual limiting diffusion coefficients of the molecular, D m 0 , and ionized forms, D ± 0 , of this drug. - Abstract: Binary mutual diffusion coefficients measured by the Taylor dispersion method, for aqueous solutions of paracetamol (PA) at concentrations from (0.001 to 0.050) mol·dm −3 at T = 298.15 K, are reported. From the Nernst–Hartley equation and our experimental results, the limiting diffusion coefficient of this drug and its thermodynamic factors are estimated, thereby contributing in this way to a better understanding of the structure of such systems and of their thermodynamic behaviour in aqueous solution at different concentrations.

  10. Isopiestic determination of the osmotic and activity coefficients of the {yKCl + (1 - y)K2HPO4}(aq) system at T = 298.15 K

    International Nuclear Information System (INIS)

    Popovic, Daniela Z.; Miladinovic, Jelena; Todorovic, Milica D.; Zrilic, Milorad M.; Rard, Joseph A.

    2011-01-01

    Highlights: → Isopiestic measurements were made for {yKCl + (1 - y)K 2 HPO 4 }(aq) at T = 298.15 K. → The resulting osmotic coefficients were represented by three thermodynamic models. → Activity coefficients from Pitzer model with Scatchard mixing terms are recommended. - Abstract: The osmotic coefficients of aqueous mixtures of KCl and K 2 HPO 4 have been measured at T = (298.15 ± 0.01) K by the isopiestic vapor pressure method over the range of ionic strengths from (2.3700 to 11.250) mol . kg -1 using CaCl 2 (aq) as the reference solution. Our new experimental results were modeled with an extended form of Pitzer's ion-interaction model equations, both with the usual mixing terms and with Scatchard's neutral-electrolyte mixing terms, and with the Clegg-Pitzer-Brimblecombe equations based on the mole-fraction-composition scale. There is a dearth of previously published isopiestic data for mixtures containing salts of HPO 4 2- (aq) and, consequently, no previous measurements are available for comparison with the present results. The present study yields Cl - HPO 4 2- mixing parameters for these three models that are needed for modeling the thermodynamic activities of solute components of natural waters and other complex aqueous electrolyte mixtures.

  11. Dilution physics modeling: Dissolution/precipitation chemistry

    International Nuclear Information System (INIS)

    Onishi, Y.; Reid, H.C.; Trent, D.S.

    1995-09-01

    This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, solids dissolution and generation, solids settling/rising, and convective motion of physical and chemical species. Thus this model development is important from the standpoint of predicting the consequences of various engineered activities, such as mitigation by dilution, retrieval, or pretreatment, that can affect safe operations. The integration of a dissolution/precipitation chemistry module allows the various phase species concentrations to enter into the physical calculations that affect the TEMPEST hydrodynamic flow calculations. The yield strength model of non-Newtonian sludge correlates yield to a power function of solids concentration. Likewise, shear stress is concentration-dependent, and the dissolution/precipitation chemistry calculations develop the species concentration evolution that produces fluid flow resistance changes. Dilution of waste with pure water, molar concentrations of sodium hydroxide, and other chemical streams can be analyzed for the reactive species changes and hydrodynamic flow characteristics

  12. Measurement of gas/water uptake coefficients for trace gases active in the marine environment. [Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, P. [Boston Coll., Chestnut Hill, MA (United States). Dept. of Chemistry; Worsnop, D.W.; Zahniser, M.S.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics

    1992-02-01

    Ocean produced reduced sulfur compounds including dimethylsulfide (DMS), hydrogen sulfide (H{sub 2}S), carbon disulfide (CS{sub 2}), methyl mercaptan (CH{sub 3}CH) and carbonyl sulfide (OCS) deliver a sulfur burden to the atmosphere which is roughly equal to sulfur oxides produced by fossil fuel combustion. These species and their oxidation products dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO{sub 2}) and methane sulfonic acid (MSA) dominate aerosol and CCN production in clean marine air. Furthermore, oxidation of reduced sulfur species will be strongly influenced by NO{sub x}/O{sub 3} chemistry in marine atmospheres. The multiphase chemical processes for these species must be understood in order to study the evolving role of combustion produced sulfur oxides over the oceans. We have measured the chemical and physical parameters affecting the uptake of reduced sulfur compounds, their oxidation products, ozone, and nitrogen oxides by the ocean`s surface, and marine clouds, fogs, and aerosols. These parameters include: gas/surface mass accommodation coefficients; physical and chemically modified (effective) Henry`s law constants; and surface and liquid phase reaction constants. These parameters are critical to understanding both the interaction of gaseous trace species with cloud and fog droplets and the deposition of trace gaseous species to dew covered, fresh water and marine surfaces.

  13. Dilute chemical decontamination program review

    International Nuclear Information System (INIS)

    Anstine, L.D.; Blomgren, J.C.; Pettit, P.J.

    1980-01-01

    The objective of the Dilute Chemical Decontamination Program is to develop and evaluate a process which utilizes reagents in dilute concentrations for the decontamination of BWR primary systems and for the maintenance of dose rates on the out-of-core surfaces at acceptable levels. A discussion is presented of the process concept, solvent development, advantages and disadvantages of reagent systems, and VNC loop tests. Based on the work completed to date it is concluded that (1) rapid decontamination of BWRs using dilute reagents is feasible; (2) reasonable reagent conditions for rapid chemical decontamination are: 0.01M oxalic acid + 0.005M citric acid, pH3.0, 90/degree/C, 0.5 to 1.0 ppm dissolved oxygen; (3) control of dissolved oxygen concentration is important, since high levels suppress the rate of decontamination and low levels allow precipitation of ferrous oxalate. 4 refs

  14. Measurements of heat transfer coefficients at low contact pressures for actively cooled bolted armour concepts in Tore Supra

    International Nuclear Information System (INIS)

    Lipa, M.; Chappuis, Ph.; Dufayet, A.

    2000-01-01

    For the future upgrade of inner vessel components (CIEL project) a guard limiter for plasma ramp-up and disruption protection will be installed on the high field side of the vacuum vessel. Among transient heat loads, this structure has to sustain a moderate heat flux in the range of ≤0.5 MW/m 2 during quasi steady state operation (1000 s). A bolted carbon-carbon (C-C) tile is preferred compared with a brazed tile solution due to the expected moderate heat fluxes, costs and the possibility of rapid replacement of individual tiles. Large flat tile assemblies require a sufficient soft and conductive compliant layer enclosed between tile and heat sink in order to avoid thermal contact loss of the assembly during heat loads and therefore minimising the tile surface temperature. The global heat transfer coefficient (H gl ) under vacuum at low contact pressures (0.5-1.5 MPa) between C-C and CuCrZr heat sink substrata has been measured in the experimental device, installation of contact heat transfer measurements (ITTAC), using different compliant materials. It appears that the best compliant layer is a graphite sheet (PAPYEX), compared with copper-felt/foam material. As an example, a H gl number of ∼10 4 W/m 2 K at an average contact pressure of 0.5 MPa has been measured near room temperature between C-C (SEP N11) and CuCrZr substrata using a 0.5-mm thick PAPYEX layer. Thermohydraulic calculations (2D) of the guard limiter design show an expected tile surface temperature of about 550 deg. C in steady state regime for an incident heat flux of 0.5 MW/m 2

  15. Attenuation coefficients of soils

    International Nuclear Information System (INIS)

    Martini, E.; Naziry, M.J.

    1989-01-01

    As a prerequisite to the interpretation of gamma-spectrometric in situ measurements of activity concentrations of soil radionuclides the attenuation of 60 to 1332 keV gamma radiation by soil samples varying in water content and density has been investigated. A useful empirical equation could be set up to describe the dependence of the mass attenuation coefficient upon photon energy for soil with a mean water content of 10%, with the results comparing well with data in the literature. The mean density of soil in the GDR was estimated at 1.6 g/cm 3 . This value was used to derive the linear attenuation coefficients, their range of variation being 10%. 7 figs., 5 tabs. (author)

  16. The activity of γ-emitters as measured by ionisation chambers the determination of the specific emission coefficient γ for some radio-elements (1961)

    International Nuclear Information System (INIS)

    Engelmann, J.

    1962-06-01

    The object of this work is to study techniques of measurement using the gamma ionisation chamber, making it possible either to measure the activities of radioactive sources, or to determine the specific emission coefficient γ (or the coefficient K) of a given radioelement. The ionisation chambers studied belong to two categories: graphites cavity-chambers, and 4 π γ chambers. For the cavity-chamber measurements, the different correction factors of which account must be taken have been calculated, in particular the geometric and hygrometric corrections. The absorption and auto-absorption corrections have led to the introduction of the notion of the 'effective energy γ' of a radioelement. In the case of 4 π γ chambers, it has been shown that appropriately shaped electrodes make it possible to improve their performances. One of the chambers described permits the measurement of β emitters using the associated Bremsstrahlung. In order to measure the K coefficient of some radioelements, it has been found useful a 4 π γ chamber with graphite walls, the measurement being carried out by comparison with a radium standard. The validity of the method was checked with radioelements for whom the K coefficient values are well-known ( 24 Na, 60 Co, 131 I, 198 Au). For other radioelements, the following values were obtained (expressed in r cm 3 mc -1 h -1 ): 51 Cr: 0,18; 56 Mn: 8,8; 65 Zn: 3,05; 124 Sb: 9,9; 134 Cs: 9,3; 137 Cs: 3,35; 141 Ce: 0,46; 170 Tm: 0,023; 192 Ir: 24,9; 203 Hg: 1,18; These values have been corrected for the contribution to the dose of the fluorescent radiation which may be emitted by the source, except in the case of Tm 170 . In the last part of this work, the performances of the different electro-metric devices used were compared. (author) [fr

  17. Classification of alpha-active workplace aerosols based on coefficient of transportability as measured by the dialysis method

    International Nuclear Information System (INIS)

    Khokhryakov, V.F.; Suslova, K.G.; Tseveloyova, I.A.; Aladova, E.E.; Filipy, R.E.

    1998-01-01

    This report describes a method by which potentially inhaled workplace aerosols containing plutonium compounds are classified on the basis of measured transportability in Ringer's solution. It is suggested that the criterion 'transportability' be used in the ICRP respiratory tract model. Transportability is measured as the fraction of plutonium alpha activity, deposited on a collecting filter, that passes through a semi-permeable membrane in Ringer's physiological solution during two days of dialysis. First order kinetic equations are used for explanation of dialysis results. The dissolution characteristics of alpha-active aerosols are important in interpretation of their passage from the lungs after inhalation. (author)

  18. Activity coefficients and excess Gibbs' free energy of some binary mixtures formed by p-cresol at 95.23 kPa

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, T.E. Vittal [Properties Group, Chemical Engineering Laboratory, Indian Institute of Chemical Technology, Hyderabad 500 007 (India); Venkanna, N. [Swamy Ramanandateertha Institute of Science and Technology, Hyderabad 508 004 (India); Kumar, Y. Naveen [Swamy Ramanandateertha Institute of Science and Technology, Hyderabad 508 004 (India); Ashok, K. [Swamy Ramanandateertha Institute of Science and Technology, Hyderabad 508 004 (India); Sirisha, N.M. [Swamy Ramanandateertha Institute of Science and Technology, Hyderabad 508 004 (India); Prasad, D.H.L. [Properties Group, Chemical Engineering Laboratory, Indian Institute of Chemical Technology, Hyderabad 500 007 (India)]. E-mail: dasika@iict.res.in

    2007-07-15

    Bubble point temperatures at 95.23 kPa, over the entire composition range are measured for the binary mixtures formed by p-cresol with 1,2-dichloroethane, 1,1,2,2-tetrachloroethane trichloroethylene, tetrachloroethylene, and o- , m- , and p-xylenes, making use of a Swietoslawski-type ebulliometer. Liquid phase mole fraction (x {sub 1}) versus bubble point temperature (T) measurements are found to be well represented by the Wilson model. The optimum Wilson parameters are used to calculate the vapor phase composition, activity coefficients, and excess Gibbs free energy. The results are discussed.

  19. Spectrophotometric Analysis of the Kinetic of Pd(II Chloride Complex Ions Sorption Process from Diluted Aqua Solutions Using Commercially Available Activated Carbon

    Directory of Open Access Journals (Sweden)

    Wojnicki M.

    2017-12-01

    Full Text Available In this paper, results of adsorption kinetic studies of Pd(II chloride complex ions on activated carbon Organosrob 10 CO are presented. Spectorphotometrical method was applied to investigate the process. Kinetic model was proposed, and fundamental thermodynamic parameters were determined. Proposed kinetic model describes well observed phenomenon in the studied range of concentration of Pd(II chloride complex ions as well, as concentration of activated carbon.

  20. Paradigms in isotope dilution mass spectrometry for elemental speciation analysis

    International Nuclear Information System (INIS)

    Meija, Juris; Mester, Zoltan

    2008-01-01

    Isotope dilution mass spectrometry currently stands out as the method providing results with unchallenged precision and accuracy in elemental speciation. However, recent history of isotope dilution mass spectrometry has shown that the extent to which this primary ratio measurement method can deliver accurate results is still subject of active research. In this review, we will summarize the fundamental prerequisites behind isotope dilution mass spectrometry and discuss their practical limits of validity and effects on the accuracy of the obtained results. This review is not to be viewed as a critique of isotope dilution; rather its purpose is to highlight the lesser studied aspects that will ensure and elevate current supremacy of the results obtained from this method

  1. Effect of particle size on dc conductivity, activation energy and diffusion coefficient of lithium iron phosphate in Li-ion cells

    Directory of Open Access Journals (Sweden)

    T.V.S.L. Satyavani

    2016-03-01

    Full Text Available Cathode materials in nano size improve the performance of batteries due to the increased reaction rate and short diffusion lengths. Lithium Iron Phosphate (LiFePO4 is a promising cathode material for Li-ion batteries. However, it has its own limitations such as low conductivity and low diffusion coefficient which lead to high impedance due to which its application is restricted in batteries. In the present work, increase of conductivity with decreasing particle size of LiFePO4/C is studied. Also, the dependence of conductivity and activation energy for hopping of small polaron in LiFePO4/C on variation of particle size is investigated. The micro sized cathode material is ball milled for different durations to reduce the particle size to nano level. The material is characterized for its structure and particle size. The resistivities/dc conductivities of the pellets are measured using four probe technique at different temperatures, up to 150 °C. The activation energies corresponding to different particle sizes are calculated using Arrhenius equation. CR2032 cells are fabricated and electrochemical characteristics, namely, ac impedance and diffusion coefficients, are studied.

  2. Primary system boron dilution analysis

    International Nuclear Information System (INIS)

    Crump, R.J.; Naretto, C.J.; Borgen, R.A.; Rockhold, H.C.

    1978-01-01

    The results are presented for an analysis conducted to determine the potential paths through which nonborated water or water with insufficient boron concentration might enter the LOFT primary coolant piping system or reactor vessel to cause dilution of the borated primary coolant water. No attempt was made in the course of this analysis to identify possible design modifications nor to suggest changes in administrative procedures or controls

  3. The Effect of Dilution on Microsegregation in AWS ER NiCrMo-14 Alloy Welding Claddings

    Science.gov (United States)

    Miná, Émerson Mendonça; da Silva, Yuri Cruz; Dille, Jean; Silva, Cleiton Carvalho

    2016-12-01

    Dilution and microsegregation are phenomena inherent to claddings, which, in turn, directly affect their main properties. This study evaluated microsegregation in the fusion zone with different dilution levels. The overlays were welded by the TIG cold wire feed process. Dilution was calculated from the geometric characteristics of the claddings and from the conservation of mass equation using chemical composition measurements. Microsegregation was calculated using energy dispersive X-ray spectroscopy measurements of the dendrites and the chemical composition of the fusion zone. The dilution of the claddings was increased by reducing the wire feed rate. Fe showed potential to be incorporated into the solid phase ( k > 1), and this increased with the increase of dilution. Mo, in turn, was segregated into the liquid phase ( k < 1) and also increased with the increase of dilution. However, Cr and W showed a slight decrease in their partition coefficients ( k) with the increase of dilution.

  4. Cryogen-free dilution refrigerators

    International Nuclear Information System (INIS)

    Uhlig, K

    2012-01-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4 He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4 He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  5. Cryogen-free dilution refrigerators

    Science.gov (United States)

    Uhlig, K.

    2012-12-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  6. Plutonium determination by isotope dilution

    International Nuclear Information System (INIS)

    Lucas, M.

    1980-01-01

    The principle is to add to a known amount of the analysed solution a known amount of a spike solution consisting of plutonium 242. The isotopic composition of the resulting mixture is then determined by surface ionization mass spectrometry, and the plutonium concentration in the solution is deduced, from this measurement. For irradiated fuels neutronic studies or for fissile materials balance measurements, requiring the knowledge of the ratio U/Pu or of concentration both uranium and plutonium, it is better to use the double spike isotope dilution method, with a spike solution of known 233 U- 242 Pu ratio. Using this method, the ratio of uranium to plutonium concentration in the irradiated fuel solution can be determined without any accurate measurement of the mixed amounts of sample and spike solutions. For fissile material balance measurements, the uranium concentration is determined by using single isotope dilution, and the plutonium concentration is deduced from the ratio Pu/U and U concentration. The main advantages of isotope dilution are its selectivity, accuracy and very high sensitivity. The recent improvements made to surface ionization mass spectrometers have considerably increased the precision of the measurements; a relative precision of about 0.2% to 0.3% is obtained currently, but it could be reduced to 0.1%, in the future, with a careful control of the experimental procedures. The detection limite is around 0.1 ppb [fr

  7. Alkylarylnitrosoureas--stability in aqueous solution, partition coefficient, alkylating activity and its relationship to SCE induction in Chinese hamster V 79-E cells.

    Science.gov (United States)

    Mendel, J; Thust, R; Schwarz, H

    1982-01-01

    The alkylating activity, chemical stability in aqueous solution (pH 7.0; 37 degrees C), and partition coefficient (octanol/water) of the following compounds were determined: 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1-isopropyl-3-phenyl-1-nitrosourea (i-PrPNU), 1-methyl-3-(p-fluorophenyl)-1-nitrosourea (F-MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (Cl-MPNU), 1-methyl-3-(p-bromophenyl)-1-nitrosourea (Br-MPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU), and 1-methyl-3-naphthyl-1-nitrosocarbamate (NCA). 1-Methyl-1-nitrosourea (MNU) and 1-ethyl-1-nitrosourea (ENU) were used for the comparison. THe rate of decomposition in aqueous solution is discussed concerning the influences of the substituents at the 1- and 3-N-atom. The mono- and disubstituted N-nitrosoureas showed a coarse correlation between alkylating activity and SCE induction in Chinese hamster V 79-E cells. On the other hand, this correlation is missing in the case of NCA, which is a potent SCE inducer despite relatively low alkylating activity. DMPNU is the strongest SCE inducer, but this compound shows a high stability in aqueous solution and, consequently, we were not able to detect an alkylating activity.

  8. Effect of Silicon on the Activity Coefficient of Rhenium in Fe-Si Liquids: Implications for HSE and Os Isotopes in Planetary Mantles

    Science.gov (United States)

    Righter, K.; Pando, K.; Yang, S.; Humayun, M.

    2018-01-01

    Metallic cores contain light alloying elements that can be a combination of S, C, Si, and O, all of which have important chemical and physical influences. For Earth, Si may be the most abundant light element in the core. Si dissolved into Fe liquids can have a large effect on the magnitude of the activity coefficient of siderophile elements (SE), and thus the partitioning behavior of those elements between core and mantle. The effect of Si on the highly siderophile elements is only beginning to be studied and the effects on Au, Pd and Pt are significant. Here we report new experiments designed to quantify the effect of Si on the partitioning of Re between metal and silicate melt. A solid understanding of Re partitioning is required for a complete understanding of the Re-Os isotopic systems. The results will be applied to understanding the HSEs and Os isotopic data for planetary mantles, and especially Earth.

  9. Effect of Silicon on Activity Coefficients of Siderophile Elements (P, Au, Pd, As, Ge, Sb, and In) in Liquid Fe, with Application to Core Formation

    Science.gov (United States)

    Righter, K.; Pando, K.; Danielson, L. R.; Humayun, M.; Righter, M.; Lapen, T.; Boujibar, A.

    2016-01-01

    Earth's core contains approximately 10 percent light elements that are likely a combination of S, C, Si, and O, with Si possibly being the most abundant. Si dissolved into Fe liquids can have a large effect on the magnitude of the activity coefficient of siderophile elements (SE) in Fe liquids, and thus the partitioning behavior of those elements between core and mantle. The effect of Si can be small such as for Ni and Co, or large such as for Mo, Ge, Sb, As. The effect of Si on many siderophile elements is unknown yet could be an important, and as yet unquantified, influence on the core-mantle partitioning of SE. Here we report new experiments designed to quantify the effect of Si on the partitioning of P, Au, Pd, and many other SE between metal and silicate melt. The results will be applied to Earth, for which we have excellent constraints on the mantle siderophile element concentrations.

  10. A Study on the Stability of Diluted Bee Venom Solution

    Directory of Open Access Journals (Sweden)

    Mi-Suk Kang

    2003-06-01

    Full Text Available Objective : The purpose of this study was to investigate the stability of bee venom according to the keeping method and period. Method : The author observed microbial contamination of bee venom in nutrient agar, broth, YPD agar and YPD media and antibacterial activity for S. aureus, E. coli manufactured 12, 6 and 3 months ago as the two type of room temperature and 4℃ cold storage. Result : 1. 1:3,000 and 1:4,000 diluted bee venom solution did not show microbial contamination both room temperature and cold storage within twelve months. 2. There was antibacterial activity of diluted bee venom for S. aureus in cold storage within twelve months and there was no antibacterial activity of diluted bee venom for S. aureus in twelve months, room temperature storage. 3. We could not observe the zone of inhibition around paper disc of all for E.coli. in 1:3,000, 1:30,000 and 1:3,000,000 diluted bee venom solution, respectively. According to results, we expect that diluted bee venom solution is stable both cold and room temperature storage within twelve months.

  11. A miniaturized plastic dilution refrigerator

    International Nuclear Information System (INIS)

    Bindilatti, V.; Oliveira, N.F.Jr.; Martin, R.V.; Frossati, G.

    1996-01-01

    We have built and tested a miniaturized dilution refrigerator, completely contained (still, heat exchanger and mixing chamber) inside a plastic (PVC) tube of 10 mm diameter and 170 mm length. With a 25 cm 2 CuNi heat exchanger, it reached temperatures below 50 mK, for circulation rates below 70 μmol/s. The cooling power at 100 mK and 63 μmol/s was 45 μW. The experimental space could accommodate samples up to 6 mm in diameter. (author)

  12. Isotope dilution mass spectrometry as the primary method of measurement for the amount of matter. Application to cadmium determination in biological materials and comparison with instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Munoz, Luis; Gras, Nuri; Quejido, Alberto; Ferrada, Carlos

    2001-01-01

    using the nuclear techniques Instrumental Neutron Activation Analysis and with Radiochemical Separations. The Isotope Dilution Mass Spectrometry technique developed in the Chilean Nuclear Energy Commission's Chemical Metrology laboratories strengthens its analytical capacities and reinforces the reference laboratory's role in the growing National Chemical Metrology Network

  13. The Statistical Mechanics of Dilute, Disordered Systems

    Science.gov (United States)

    Blackburn, Roger Michael

    Available from UMI in association with The British Library. Requires signed TDF. A graph partitioning problem with variable inter -partition costs is studied by exploiting its mapping on to the Ashkin-Teller spin glass. The cavity method is used to derive the TAP equations and free energy for both extensively connected and dilute systems. Unlike Ising and Potts spin glasses, the self-consistent equation for the distribution of effective fields does not have a solution solely made up of delta functions. Numerical integration is used to find the stable solution, from which the ground state energy is calculated. Simulated annealing is used to test the results. The retrieving activity distribution for networks of boolean functions trained as associative memories for optimal capacity is derived. For infinite networks, outputs are shown to be frozen, in contrast to dilute asymmetric networks trained with the Hebb rule. For finite networks, a steady leaking to the non-retrieving attractor is demonstrated. Simulations of quenched networks are reported which show a departure from this picture: some configurations remain frozen for all time, while others follow cycles of small periods. An estimate of the critical capacity from the simulations is found to be in broad agreement with recent analytical results. The existing theory is extended to include noise on recall, and the behaviour is found to be robust to noise up to order 1/c^2 for networks with connectivity c.

  14. Individual Tracer Atoms in an Ultracold Dilute Gas

    Science.gov (United States)

    Hohmann, Michael; Kindermann, Farina; Lausch, Tobias; Mayer, Daniel; Schmidt, Felix; Lutz, Eric; Widera, Artur

    2017-06-01

    We report on the experimental investigation of individual Cs atoms impinging on a dilute cloud of ultracold Rb atoms with variable density. We study the relaxation of the initial nonthermal state and detect the effect of single collisions which has so far eluded observation. We show that, after few collisions, the measured spatial distribution of the tracer atoms is correctly described by a Langevin equation with a velocity-dependent friction coefficient, over a large range of Knudsen numbers. Our results extend the simple and effective Langevin treatment to the realm of light particles in dilute gases. The experimental technique developed opens up the microscopic exploration of a novel regime of diffusion at the level of individual collisions.

  15. A model for the viscosity of dilute smectite gels

    International Nuclear Information System (INIS)

    Liu, L.

    2011-01-01

    A simple yet accurate model describing the viscosity of dilute suspensions of sodium montmorillonite in dilute homo-ionic solutions is presented. Taking the clay particle and the surrounding clouds of ions as a whole as an uncharged but soft, coin-like particle, the Huggins' equation for a suspension of uncharged particles is extended in the model to account for not only the primary and the secondary electro-viscous effects, but also the multi-particle interaction. The agreements between the predicted and measured results are excellent. The Huggins' coefficient obtained compares favorably with available data, while the intrinsic viscosity reduces to the Simha's equation in the large limit of ionic strength, suggesting that the model is robust. (authors)

  16. Osmotic and activity coefficients in the binary solutions of 1-butyl-3-methylimidazolium chloride and bromide in methanol or ethanol at T = 298.15 K from isopiestic measurements

    International Nuclear Information System (INIS)

    Sardroodi, Jaber Jahanbin; Azamat, Jafar; Atabay, Maryam

    2011-01-01

    Highlights: → The osmotic coefficients of the solutions of 1-butyl-3-methylimidazolium chloride and bromide in ethanol and methanol have been measured. → Measured osmotic coefficients were correlated using NRTL and Pitzer models. → Vapor pressures were evaluated from the correlated osmotic coefficients. → Model parameters have been interpreted in terms of ion-ion and ion-solvent interactions. - Abstract: Osmotic coefficients of the binary solutions of two room-temperature ionic liquids (1-butyl-3-methylimidazolium chloride and bromide) in methanol and ethanol have been measured at T = 298.15 K by the isopiestic method. The experimental osmotic coefficient data have been correlated using a forth-order polynomial in terms of (molality) 0.5 , with both, ion interaction model of Pitzer and electrolyte non-random two liquid (e-NRTL) model of Chen. The values of vapor pressures of above-mentioned solutions have been calculated from the osmotic coefficients. The model parameters fitted to the experimental osmotic coefficients have been used for prediction of the mean ionic activity coefficients of those ionic liquids in methanol and ethanol.

  17. Buffer erosion in dilute groundwater

    International Nuclear Information System (INIS)

    Schatz, T.; Kanerva, N.; Martikainen, J.; Sane, P.; Olin, M.; Seppaelae, A.; Koskinen, K.

    2013-08-01

    One scenario of interest for repository safety assessment involves the loss of bentonite buffer material in contact with dilute groundwater flowing through a transmissive fracture interface. In order to examine the extrusion/erosion behavior of bentonite buffer material under such circumstances, a series of experiments were performed in a flow-through, 1 mm aperture, artificial fracture system. These experiments covered a range of solution chemistry (salt concentration and composition), material composition (sodium montmorillonite and admixtures with calcium montmorillonite), and flow velocity conditions. No erosion was observed for sodium montmorillonite against solution compositions from 0.5 g/L to 10 g/L NaCl. No erosion was observed for 50/50 calcium/sodium montmorillonite against 0.5 g/L NaCl. Erosion was observed for both sodium montmorillonite and 50/50 calcium/sodium montmorillonite against solution compositions ≤ 0.25 g/L NaCl. The calculated erosion rates for the tests with the highest levels of measured erosion, i.e., the tests run under the most dilute conditions (ionic strength (IS) < ∼1 mM), were well-correlated to flow velocity, whereas the calculated erosion rates for the tests with lower levels of measured erosion, i.e., the tests run under somewhat less dilute conditions (∼1 mM < IS < ∼4 mM), were not similarly correlated indicating that material and solution composition can significantly affect erosion rates. In every experiment, both erosive and non-erosive, emplaced buffer material extruded into the fracture and was observed to be impermeable to water flowing in the fracture effectively forming an extended diffusive barrier around the intersecting fracture/buffer interface. Additionally, a model which was developed previously to predict the rate of erosion of bentonite buffer material in low ionic strength water in rock fracture environments was applied to three different cases: sodium montmorillonite expansion in a vertical tube, a

  18. Isopiestic Investigation of the Osmotic and Activity Coefficients of {yMgCl2 + (1 - y)MgSO4}(aq) and the Osmotic Coefficients of Na2SO4.MgSO4(aq) at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Miladinovic, J; Ninkovic, R; Todorovic, M; Rard, J A

    2007-06-06

    Isopiestic vapor pressure measurements were made for {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) solutions with MgCl{sub 2} ionic strength fractions of y = 0, 0.1997, 0.3989, 0.5992, 0.8008, and (1) at the temperature 298.15 K, using KCl(aq) as the reference standard. These measurements for the mixtures cover the ionic strength range I = 0.9794 to 9.4318 mol {center_dot} kg{sup -1}. In addition, isopiestic measurements were made with NaCl(aq) as reference standard for mixtures of {l_brace}xNa{sub 2}SO{sub 4} + (1-x)MgSO{sub 4}{r_brace}(aq) with the molality fraction x = 0.50000 that correspond to solutions of the evaporite mineral bloedite (astrakanite), Na{sub 2}Mg(SO{sub 4}){sub 2} {center_dot} 4H{sub 2}O(cr). The total molalities, m{sub T} = m(Na{sub 2}SO{sub 4}) + m(MgSO{sub 4}), range from m{sub T} = 1.4479 to 4.4312 mol {center_dot} kg{sup -1} (I = 5.0677 to 15.509 mol {center_dot} kg{sup -1}), where the uppermost concentration is the highest oversaturation molality that could be achieved by isothermal evaporation of the solvent at 298.15 K. The parameters of an extended ion-interaction (Pitzer) model for MgCl2(aq) at 298.15 K, which were required for an analysis of the {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) mixture results, were evaluated up to I = 12.025 mol {center_dot} kg{sup -1} from published isopiestic data together with the six new osmotic coefficients obtained in this study. Osmotic coefficients of {l_brace}yMgCl{sub 2} + (1-y)MgSO{sub 4}{r_brace}(aq) solutions from the present study, along with critically-assessed values from previous studies, were used to evaluate the mixing parameters of the extended ion-interaction model.

  19. Desynchronization in diluted neural networks

    International Nuclear Information System (INIS)

    Zillmer, Ruediger; Livi, Roberto; Politi, Antonio; Torcini, Alessandro

    2006-01-01

    The dynamical behavior of a weakly diluted fully inhibitory network of pulse-coupled spiking neurons is investigated. Upon increasing the coupling strength, a transition from regular to stochasticlike regime is observed. In the weak-coupling phase, a periodic dynamics is rapidly approached, with all neurons firing with the same rate and mutually phase locked. The strong-coupling phase is characterized by an irregular pattern, even though the maximum Lyapunov exponent is negative. The paradox is solved by drawing an analogy with the phenomenon of 'stable chaos', i.e., by observing that the stochasticlike behavior is 'limited' to an exponentially long (with the system size) transient. Remarkably, the transient dynamics turns out to be stationary

  20. A compact rotating dilution refrigerator

    Science.gov (United States)

    Fear, M. J.; Walmsley, P. M.; Chorlton, D. A.; Zmeev, D. E.; Gillott, S. J.; Sellers, M. C.; Richardson, P. P.; Agrawal, H.; Batey, G.; Golov, A. I.

    2013-10-01

    We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid 4He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 10-3 rad s-1 up to angular velocities in excess of 2.5 rad s-1. The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated.

  1. Introduction to the Physics of Diluted Magnetic Semiconductors

    CERN Document Server

    Gaj, Jan A

    2010-01-01

    The book deals with diluted magnetic semiconductors, a class of materials important to the emerging field of spintronics. In these materials semiconducting properties, both transport and optical, are influenced by the presence of magnetic ions. It concentrates on basic physical mechanisms (e.g. carrier-ion and ion-ion interactions) and resulting phenomena (e.g. magnetic polaron formation and spin relaxation). Introduction to the Physics of Diluted Magnetic Semiconductors is addressed to graduate-level and doctoral students and young researchers entering the field. The authors have been actively involved in the creation of this branch of semiconductor physics.

  2. Dispersion of Sound in Dilute Suspensions with Nonlinear Particle Relaxation

    Science.gov (United States)

    Kandula, Max

    2010-01-01

    The theory accounting for nonlinear particle relaxation (viscous and thermal) has been applied to the prediction of dispersion of sound in dilute suspensions. The results suggest that significant deviations exist for sound dispersion between the linear and nonlinear theories at large values of Omega(Tau)(sub d), where Omega is the circular frequency, and Tau(sub d) is the Stokesian particle relaxation time. It is revealed that the nonlinear effect on the dispersion coefficient due to viscous contribution is larger relative to that of thermal conduction

  3. Activity coefficients of LiCl in (PEG 4000 + water) at T = (288.15, 298.15, and 308.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Morales, Jaime W.; Galleguillos, Hector R.; Graber, Teofilo A. [Centro de Investigacion Cientifico y Tecnologico para la Mineria, Departamento de Ingenieria Quimica, Universidad de Antofagasta (Chile); Hernandez-Luis, Felipe, E-mail: ffhelu@ull.e [Departamento de Quimica Fisica, Universidad de La Laguna, Tenerife (Spain)

    2010-10-15

    The electromotive force of the cell containing two ion-selective electrodes (ISE), Na-ISE|LiCl(m),PEG4000(w),H{sub 2}O(1-w)|Cl-ISE has been measured at temperatures of (288.15, 298.15, and 308.15) K as a function of the mass fraction of PEG 4000 (w) in the mixture. w was varied between 0 and 0.25 in 0.05-unit steps and the molality of the electrolyte (m) was between c.a. (0.03 and 5.8) mol . kg{sup -1}. The values of the standard electromotive force, E{sup 0}, were determined using routine methods of extrapolation, together with extended Debye-Hueckel and Pitzer equations. The results obtained produced good internal consistency for all the temperatures studied. Once E{sup 0} was determined, the mean ionic activity coefficients for LiCl, the Gibbs free energy of transfer from the water to (PEG 4000 + water), and the primary LiCl hydration number were calculated.

  4. Activity coefficients of LiCl in (PEG 4000 + water) at T = (288.15, 298.15, and 308.15) K

    International Nuclear Information System (INIS)

    Morales, Jaime W.; Galleguillos, Hector R.; Graber, Teofilo A.; Hernandez-Luis, Felipe

    2010-01-01

    The electromotive force of the cell containing two ion-selective electrodes (ISE), Na-ISE|LiCl(m),PEG4000(w),H 2 O(1-w)|Cl-ISE has been measured at temperatures of (288.15, 298.15, and 308.15) K as a function of the mass fraction of PEG 4000 (w) in the mixture. w was varied between 0 and 0.25 in 0.05-unit steps and the molality of the electrolyte (m) was between c.a. (0.03 and 5.8) mol . kg -1 . The values of the standard electromotive force, E 0 , were determined using routine methods of extrapolation, together with extended Debye-Hueckel and Pitzer equations. The results obtained produced good internal consistency for all the temperatures studied. Once E 0 was determined, the mean ionic activity coefficients for LiCl, the Gibbs free energy of transfer from the water to (PEG 4000 + water), and the primary LiCl hydration number were calculated.

  5. Fast and accurate calculation of dilute quantum gas using Uehling–Uhlenbeck model equation

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Ryosuke, E-mail: ryosuke.yano@tokiorisk.co.jp

    2017-02-01

    The Uehling–Uhlenbeck (U–U) model equation is studied for the fast and accurate calculation of a dilute quantum gas. In particular, the direct simulation Monte Carlo (DSMC) method is used to solve the U–U model equation. DSMC analysis based on the U–U model equation is expected to enable the thermalization to be accurately obtained using a small number of sample particles and the dilute quantum gas dynamics to be calculated in a practical time. Finally, the applicability of DSMC analysis based on the U–U model equation to the fast and accurate calculation of a dilute quantum gas is confirmed by calculating the viscosity coefficient of a Bose gas on the basis of the Green–Kubo expression and the shock layer of a dilute Bose gas around a cylinder.

  6. Isopiestic Determination of the Osmotic and Activity Coefficients of Li2SO4(aq) at T=298.15 and 323.15 K, and Representation with an Extended Ion-Interaction (Pitzer) Model

    Energy Technology Data Exchange (ETDEWEB)

    Rard, Joseph A. [Lawrence Livermore National Laboratory (LLNL); Clegg, Simon L. [University of East Anglia, Norwich, United Kingdom; Palmer, Donald [ORNL

    2007-01-01

    Isopiestic vapor-pressure measurements were made for Li{sub 2}SO{sub 4}(aq) from 0.1069 to 2.8190 mol{center_dot}kg{sup -1} at 298.15 K, and from 0.1148 to 2.7969 mol{center_dot}kg{sup -1} at 323.15 K, with NaCl(aq) as the reference standard. Published thermodynamic data for this system were reviewed, recalculated for consistency, and critically assessed. The present results and the more reliable published results were used to evaluate the parameters of an extended version of Pitzer's ion-interaction model with an ionic-strength dependent third-virial coefficient, as well as those of the standard Pitzer model, for the osmotic and activity coefficients at both temperatures. Published enthalpies of dilution at 298.15 K were also analyzed to yield the parameters of the ion-interaction models for the relative apparent molar enthalpies of dilution. The resulting models at 298.15 K are valid to the saturated solution molality of the thermodynamically stable phase Li{sub 2}SO{sub 4}{center_dot}H{sub 2}O(cr). Solubilities of Li{sub 2}SO{sub 4}{center_dot}H{sub 2}O(cr) at 298.15 K were assessed and the selected value of m(sat.)=3.13{+-}0.04 mol{center_dot}kg{sup -1} was used to evaluate the thermodynamic solubility product K {sub s}(Li{sub 2}SO{sub 4}{center_dot}H{sub 2}O, cr, 298.15 K) = (2.62{+-}0.19) and a CODATA-compatible standard molar Gibbs energy of formation {Delta}{sub f} G m{sup 0}(Li{sub 2}SO{sub 4}{center_dot}H{sub 2}O, cr, 298.15 K) = -(1564.6{+-}0.5) kJ{center_dot}mol{sup -1}.

  7. Dynamics of dilute polymer solutions

    International Nuclear Information System (INIS)

    Nicholson, L.K.; Higgins, J.S.

    1980-01-01

    Neutrons scattered by nuclei undergoing slow motion e.g. the internal motion within polymer chains, lose or gain very small amounts of energy. It is therefore the quasi-elastic region of the neutron scattering spectrum which is of interest and in particular the time correlation function (or intermediate scattering law S(Q,t)) which is ideally required to define the motion. The neutron spin echo spectrometer (IN11) at the ILL facilitates the measurement of very small energy changes (down to 10 neV) on scattering from a sample, by changing and keeping track of neutron beam polarization non-parallel to the magnetic guide-field (1). The resultant neutron beam polarization, when normalized against a standard (totally elastic) scatterer is directly proportional to the cosine Fourier Transform of the scattering law S(Q,ω), which is to say the time correlation function is measured directly. Dilute solutions of deuterated polystyrene (PSD) and deuterated polytetrahydrofuran (PTDF) in carbon disulphide, and of their hydrogeneous counterparts (PSH and PTHF respectively) in deuterated benzene were investigated in the range 0.027 A -1 -1 , at 30 0 C. (orig./FKS)

  8. Storm Sewage Dilution in Smaller Streams

    DEFF Research Database (Denmark)

    Larsen, Torben; Vestergaard, Kristian

    1987-01-01

    A numerical model has been used to show how dilution in smaller streams can be effected by unsteady hydraulic conditions caused by a storm sewage overflow.......A numerical model has been used to show how dilution in smaller streams can be effected by unsteady hydraulic conditions caused by a storm sewage overflow....

  9. Cost effectiveness of dilute chemical decontamination

    International Nuclear Information System (INIS)

    LeSurf, J.E.; Weyman, G.D.

    The basic principles of dilute chemical decontamination are described, as well as the method of application. Methods of computing savings in radiation dose and costs are presented, with results from actual experience and illustrative examples. It is concluded that dilute chemical decontamination is beneficial in many cases. It reduces radiation exposure of workers, saves money, and simplifies maintenance work

  10. Kinetic theory for dilute cohesive granular gases with a square well potential

    NARCIS (Netherlands)

    Takada, Satoshi; Saitoh, K.; Hayakawa, Hisao

    2016-01-01

    We develop the kinetic theory of dilute cohesive granular gases in which the attractive part is described by a square well potential. We derive the hydrodynamic equations from the kinetic theory with the microscopic expressions for the dissipation rate and the transport coefficients. We check the

  11. Kinetic theory for dilute cohesive granular gases with a square well potential.

    Science.gov (United States)

    Takada, Satoshi; Saitoh, Kuniyasu; Hayakawa, Hisao

    2016-07-01

    We develop the kinetic theory of dilute cohesive granular gases in which the attractive part is described by a square well potential. We derive the hydrodynamic equations from the kinetic theory with the microscopic expressions for the dissipation rate and the transport coefficients. We check the validity of our theory by performing the direct simulation Monte Carlo.

  12. The CPA Equation of State and an Activity Coefficient Model for Accurate Molar Enthalpy Calculations of Mixtures with Carbon Dioxide and Water/Brine

    Energy Technology Data Exchange (ETDEWEB)

    Myint, P. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hao, Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Firoozabadi, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-03-27

    Thermodynamic property calculations of mixtures containing carbon dioxide (CO2) and water, including brines, are essential in theoretical models of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many models for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental data [1]. In this report, we recommend two different models for enthalpy calculations: the CPA equation of state by Li and Firoozabadi [2], and the CO2 activity coefficient model by Duan and Sun [3]. We show that the CPA equation of state, which has been demonstrated to provide good agreement with density and solubility data, also accurately calculates molar enthalpies of pure CO2, pure water, and both CO2-rich and aqueous (H2O-rich) mixtures of the two species. It is applicable to a wider range of conditions than the Spycher and Pruess model. In aqueous sodium chloride (NaCl) mixtures, we show that Duan and Sun’s model yields accurate results for the partial molar enthalpy of CO2. It can be combined with another model for the brine enthalpy to calculate the molar enthalpy of H2O-CO2-NaCl mixtures. We conclude by explaining how the CPA equation of state may be modified to further improve agreement with experiments. This generalized CPA is the basis of our future work on this topic.

  13. Time-integrated activity coefficient estimation for radionuclide therapy using PET and a pharmacokinetic model: A simulation study on the effect of sampling schedule and noise

    Energy Technology Data Exchange (ETDEWEB)

    Hardiansyah, Deni [Medical Radiation Physics/Radiation Protection, Medical Faculty Mannheim, Universitätsmedizin Mannheim, Heidelberg University, Mannheim 68167, Germany and Department of Radiation Oncology, Medical Faculty Mannheim, Universitätsmedizin Mannheim, Heidelberg University, Mannheim 68167 (Germany); Guo, Wei; Glatting, Gerhard, E-mail: gerhard.glatting@medma.uni-heidelberg.de [Medical Radiation Physics/Radiation Protection, Medical Faculty Mannheim, Universitätsmedizin Mannheim, Heidelberg University, Mannheim 68167 (Germany); Kletting, Peter [Department of Nuclear Medicine, Ulm University, Ulm 89081 (Germany); Mottaghy, Felix M. [Department of Nuclear Medicine, University Hospital, RWTH Aachen University, Aachen 52074, Germany and Department of Nuclear Medicine, Maastricht University Medical Center MUMC+, Maastricht 6229 (Netherlands)

    2016-09-15

    Purpose: The aim of this study was to investigate the accuracy of PET-based treatment planning for predicting the time-integrated activity coefficients (TIACs). Methods: The parameters of a physiologically based pharmacokinetic (PBPK) model were fitted to the biokinetic data of 15 patients to derive assumed true parameters and were used to construct true mathematical patient phantoms (MPPs). Biokinetics of 150 MBq {sup 68}Ga-DOTATATE-PET was simulated with different noise levels [fractional standard deviation (FSD) 10%, 1%, 0.1%, and 0.01%], and seven combinations of measurements at 30 min, 1 h, and 4 h p.i. PBPK model parameters were fitted to the simulated noisy PET data using population-based Bayesian parameters to construct predicted MPPs. Therapy simulations were performed as 30 min infusion of {sup 90}Y-DOTATATE of 3.3 GBq in both true and predicted MPPs. Prediction accuracy was then calculated as relative variability v{sub organ} between TIACs from both MPPs. Results: Large variability values of one time-point protocols [e.g., FSD = 1%, 240 min p.i., v{sub kidneys} = (9 ± 6)%, and v{sub tumor} = (27 ± 26)%] show inaccurate prediction. Accurate TIAC prediction of the kidneys was obtained for the case of two measurements (1 and 4 h p.i.), e.g., FSD = 1%, v{sub kidneys} = (7 ± 3)%, and v{sub tumor} = (22 ± 10)%, or three measurements, e.g., FSD = 1%, v{sub kidneys} = (7 ± 3)%, and v{sub tumor} = (22 ± 9)%. Conclusions: {sup 68}Ga-DOTATATE-PET measurements could possibly be used to predict the TIACs of {sup 90}Y-DOTATATE when using a PBPK model and population-based Bayesian parameters. The two time-point measurement at 1 and 4 h p.i. with a noise up to FSD = 1% allows an accurate prediction of the TIACs in kidneys.

  14. Transport Coefficients of Fluids

    CERN Document Server

    Eu, Byung Chan

    2006-01-01

    Until recently the formal statistical mechanical approach offered no practicable method for computing the transport coefficients of liquids, and so most practitioners had to resort to empirical fitting formulas. This has now changed, as demonstrated in this innovative monograph. The author presents and applies new methods based on statistical mechanics for calculating the transport coefficients of simple and complex liquids over wide ranges of density and temperature. These molecular theories enable the transport coefficients to be calculated in terms of equilibrium thermodynamic properties, and the results are shown to account satisfactorily for experimental observations, including even the non-Newtonian behavior of fluids far from equilibrium.

  15. Simplified Method for Groundwater Treatment Using Dilution and Ceramic Filter

    Science.gov (United States)

    Musa, S.; Ariff, N. A.; Kadir, M. N. Abdul; Denan, F.

    2016-07-01

    Groundwater is one of the natural resources that is not susceptible to pollutants. However, increasing activities of municipal, industrial, agricultural or extreme land use activities have resulted in groundwater contamination as occured at the Research Centre for Soft Soil Malaysia (RECESS), Universiti Tun Hussein Onn Malaysia (UTHM). Thus, aims of this study is to treat groundwater by using rainwater and simple ceramic filter as a treatment agent. The treatment uses rain water dilution, ceramic filters and combined method of dilute and filtering as an alternate treatment which are simple and more practical compared to modern or chemical methods. The water went through dilution treatment processes able to get rid of 57% reduction compared to initial condition. Meanwhile, the water that passes through the filtering process successfully get rid of as much as 86% groundwater parameters where only chloride does not pass the standard. Favorable results for the combination methods of dilution and filtration methods that can succesfully eliminate 100% parameters that donot pass the standards of the Ministry of Health and the Interim National Drinking Water Quality Standard such as those found in groundwater in RECESS, UTHM especially sulfate and chloride. As a result, it allows the raw water that will use clean drinking water and safe. It also proves that the method used in this study is very effective in improving the quality of groundwater.

  16. Theoretical modeling of diluted antiferromagnetic systems

    International Nuclear Information System (INIS)

    Pozo, J; Elgueta, R; Acevedo, R

    2000-01-01

    Some magnetic properties of a Diluted Antiferromagnetic System (DAFS) are studied. The model of the two sub-networks for antiferromagnetism is used and a Heisenberg Hamiltonian type is proposed, where the square operators are expressed in terms of boson operators with the approach of spin waves. The behavior of the diluted system's fundamental state depends basically on the competition effect between the anisotropy field and the Weiss molecular field. The approach used allows the diluted system to be worked for strong anisotropies as well as when these are very weak

  17. On the dilute gas two particle density matrices of p--H2 and He4

    International Nuclear Information System (INIS)

    Weres, O.

    1976-01-01

    In the preceding paper we demonstrated that the reduced two- particle density matrix of simple quantum liquids could profitably be re-expressed in terms of a Taylor expansion of its logarithm about the diagonal. In the present publication we examine the Taylor coefficients which arise when the dilute gas two particle density matrix is expanded in this way. In particular, we evaluate the leading coefficients of p-H 2 and He 4 exactly and extend the Wigner--Kirkwood approximation to provided approximate expressions for them. We demonstrate how these approximate expressions may be applied to yield results superior to those yielded by the ordinary Wigner--Kirkwood approximation. In an appendix we demonstrate how the Block equation for the dilute gas two particle density matrix may be reduced to an equivalent closed set of equations for the leading Taylor coefficients

  18. Predicting cyclohexane/water distribution coefficients for the SAMPL5 challenge using MOSCED and the SMD solvation model

    Science.gov (United States)

    Diaz-Rodriguez, Sebastian; Bozada, Samantha M.; Phifer, Jeremy R.; Paluch, Andrew S.

    2016-11-01

    We present blind predictions using the solubility parameter based method MOSCED submitted for the SAMPL5 challenge on calculating cyclohexane/water distribution coefficients at 298 K. Reference data to parameterize MOSCED was generated with knowledge only of chemical structure by performing solvation free energy calculations using electronic structure calculations in the SMD continuum solvent. To maintain simplicity and use only a single method, we approximate the distribution coefficient with the partition coefficient of the neutral species. Over the final SAMPL5 set of 53 compounds, we achieved an average unsigned error of 2.2± 0.2 log units (ranking 15 out of 62 entries), the correlation coefficient ( R) was 0.6± 0.1 (ranking 35), and 72± 6 % of the predictions had the correct sign (ranking 30). While used here to predict cyclohexane/water distribution coefficients at 298 K, MOSCED is broadly applicable, allowing one to predict temperature dependent infinite dilution activity coefficients in any solvent for which parameters exist, and provides a means by which an excess Gibbs free energy model may be parameterized to predict composition dependent phase-equilibrium.

  19. Effect of temperature on the dilution enthalpies of α,ω-amino acids in aqueous solutions

    International Nuclear Information System (INIS)

    Romero, C.M.; Cadena, J.C.; Lamprecht, I.

    2011-01-01

    Highlights: → The dilution of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid in water is an exothermic process at T = (293.15, 298.15, 303.15, and 308.15) K. → The limiting experimental slopes of the enthalpies of dilution with respect to the molality change Δm, are negative suggesting that the solutes interact with water primarily through their alkyl groups. → The value of the pairwise coefficient is positive at the temperatures considered, and the magnitude increases linearly with the number of methylene groups. → The comparison between the pairwise interaction coefficients for α,ω-amino acids and α-amino acids shows that the change in the enthalpic interaction coefficient is related to the relative position of the polar groups. - Abstract: Dilution enthalpies of aqueous solutions of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid were determined at T = (293.15, 298.15, 303.15, and 308.15) K using an LKB flow microcalorimeter. The homotactic interaction coefficients were obtained according to the McMillan-Mayer theory from the experimental data. For all the systems studied, the dilution of α,ω-amino acids in water is an exothermic process; the pair coefficients have positive values which increases with chain length. The obtained values of the interaction coefficients are interpreted in terms of solute-solvent and solute-solute interactions and are used as indicative of hydrophobic behavior of the amino acid studied.

  20. Radiotracer study to investigate the dilution and dispersion of sewage off Worli coast

    International Nuclear Information System (INIS)

    Yelgaonkar, V.N.; Pendharkar, A.S.; Agashe, S.M.; Kumar, U.S.; Kulkarni, U.P.; Mendhekar, G.N.; Navada, S.V.

    1998-01-01

    Radiotracer experiments were carried out off Worli Coast, Mumbai to study the dilution and dispersion of sewage from the proposed out fall at 3000 m and existing out fall at 500 m from the shore. Dilutions observed were 2.3 x 10 7 at 3.3 km from the injection point for the disposal at 3,000 m and 6.9 x 10 5 at 5 km for the disposal at 500 m. Dispersion coefficients obtained from two dimensional advection dispersion model for the experiment off 500 m are Dx 15-18 m 2 /s and Dy = 0.5-2 m 2 /s. (author)

  1. Survey of the chemical diffusion at infinite dilution in the nickel-plutonium and aluminium-uranium systems; Contribution a l'etude de l'heterodiffusion a dilution infinie systemes nickel-plutonium et aluminium-uranium

    Energy Technology Data Exchange (ETDEWEB)

    Blechet, J J [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-09-01

    Solubility S{sub 0} and chemical diffusion coefficients D{sub PuNi} at infinite dilution of plutonium in nickel have been determined by autoradiography {alpha} in poly-phased system by the welded couples method: S{sub 0} varies from 40 to 80.10{sup -6} (atomic concentration) and D{sub PuNi} follows an Arrhenius law D = D{sub 0} exp (-Q/RT) with 0.03 cm{sup 2}/s < D{sub 0} < 1.6 cm{sup 2}/s and 46000 cal/mole < Q < 56000 cal/mole. Diffusion of uranium in aluminium have been carried out by fissiography using the thin layer method. Frequency factor lies between 0.01 and 3.1 cm{sup 2}/s and the activation energy lies between 24000 and 34000 cal/mole. (author) [French] La solubilite S{sub 0} et les coefficients de diffusion chimique D{sub PuNi}, a dilution infinie, du plutonium dans le nickel ont ete determines par autoradiographie {alpha} sur des couples soudes en systeme polyphase. Entre 1000 et 1125 deg. C. S{sub 0} varie de 40 a 80.10{sup -6} et D obeit a une loi d'ARRHENIUS (concentration atomique) D = D{sub 0} exp (-Q/RT) avec 0.03 cm{sup 2}s{sup -1} < D{sub 0} < 1.60 cm{sup 2}s{sup -1} 46000 calories par mole < Q < 56000 calories par mole. La diffusion de l'uranium dans l'aluminium a ete etudiee par fissiographie en utilisant la technique du depot mince. Le facteur de frequence est situe entre 0.01 et 3.1 cm{sup 2}s{sup -1} et l'energie d'activation entre 24000 et 34000 calories par mole. (auteur)

  2. Recovery of Platinum from Dilute Chloride Media Using Biosorbents

    Science.gov (United States)

    Zeytuncu, B.; Morcali, M. H.; Yucel, O.

    Pistachio nut shells and Rice husk, a biomass residue, were investigated as adsorbents for the platinum uptake from synthetically prepared dilute chloroplatinic acid solutions. The effects of the different uptake parameters on platinum uptake (%) were studied in detail on a batch sorption. Before the pistachio nut shell material was activated, platinum uptake (%) was poor compared with rice husk. However, after the pistachio nut shell material was activated at 1000°C under an argon atmosphere, the platinum uptake (%) increased two-fold. The pistachio nut shell (inactivated and activated) and rice husk were characterized by Attenuated Total Reflection-Fourier transform infrared spectroscopy (ATR-FTIR).

  3. Renal function and plasma dabigatran level measured at trough by diluted thrombin time assay

    Directory of Open Access Journals (Sweden)

    Marta E. Martinuzzo

    2017-02-01

    Full Text Available Dabigatran etexilate (direct thrombin inhibitor is effective in preventing embolic stroke in patients with atrial fibrillation. It does not require laboratory control, but given the high renal elimination, its measurement in plasma is important in renal failure. The objectives of the study were to verify the analytical quality of the diluted thrombin time assay for measurement of dabigatran plasma concentration (cc, correlate cc with classic coagulation assays, prothrombin time (PT and activated partial thromboplastin time (APTT, and evaluate them according to the creatinine clearance (CLCr. Forty plasma samples of patients (34 consecutive and 6 suspected of drug accumulation receiving dabigatran at 150 (n = 19 or 110 (n = 21 mg/12 hours were collected. Blood samples were drawn at 10-14 hours of the last intake. Dabigatran concentration was determined by diluted thrombin time (HemosIl DTI, Instrumentation Laboratory (IL. PT and APTT (IL were performed on two fotooptical coagulometers, ACL TOP 300 and 500 (IL. DTI presented intra-assay coefficient of variation < 5.4% and inter-assay < 6%, linearity range 0-493 ng/ml. Patients' cc: median 83 (4-945 ng/ml. Individuals with CLCr in the lowest tertile (22.6-46.1 ml/min showed significantly higher median cc: 308 (49-945, compared to the average 72 (12-190 and highest tertile, 60 (4-118 ng/ml. Correlation between cc and APTT or PT were moderate, r2 = 0.59 and -0.66, p < 0.0001, respectively. DTI test allowed us to quantify plasma dabigatran levels, both in patients with normal or altered renal function, representing a useful tool in clinical situations such as renal failure, pre surgery or emergencies

  4. Calculation results and experimental testing of doppler feedback coefficients

    International Nuclear Information System (INIS)

    Yang Shunhai

    1989-01-01

    The Doppler feedback coefficients are calculated by the interpolation and group collapsing method from multigroup self-shielding factors and infinite dilution cross sections rather than effective resonance integrals by using resonance data base. Since many updated sets of multigroup data are in existence to be selected, the calculation process can be simplified. The heterogeneous effects are taken into account by equivalence relation. The computer code of Doppler feedback coefficients is created on computer CYBER-825 and PDP-11. The results calculated are in good agreement with the experiments

  5. Wastewater diffusive dilution and sedimentation of the fine contaminated particles for nonuniform flow in open channels

    Directory of Open Access Journals (Sweden)

    Lyapin Anton

    2018-01-01

    Full Text Available The influence of non-uniformity on mass transfer processes in open channels have been investigated under the action of urbanization factors. The study is related to the urgent problem of environmental degradation of water objects in urbanized areas. It is known that the water quality in the water objects depends on the manner in which the contaminants spread how they mix with the river water and diluted by it. The main results of the study consist of recommendations to incorporate non-uniformity factor to the calculation of diffusion dilution of wastewater and prediction of river processes. So the effect of the flow non-uniformity on the diffusion model of pollutants dilution and diffusion coefficient have been investigated. Formulas for the concentration profiles calculating and the average concentration of fine particulate matter in nonuniform gradually varied flow were presented. The deposition length of suspended contaminants were received, based on the hydraulic resistance laws of nonuniform gradually varied flow.

  6. Determination of activity coefficient of lanthanum chloride in molten LiCl-KCl eutectic salt as a function of cesium chloride and lanthanum chloride concentrations using electromotive force measurements

    Energy Technology Data Exchange (ETDEWEB)

    Bagri, Prashant, E-mail: prashant.bagri@utah.edu; Simpson, Michael F.

    2016-12-15

    The thermodynamic behavior of lanthanides in molten salt systems is of significant scientific interest for the spent fuel reprocessing of Generation IV reactors. In this study, the apparent standard reduction potential (apparent potential) and activity coefficient of LaCl{sub 3} were determined in a molten salt solution of eutectic LiCl-KCl as a function of concentration of LaCl{sub 3}. The effect of adding up to 1.40 mol % CsCl was also investigated. These properties were determined by measuring the open circuit potential of the La—La(III) redox couple in a high temperature molten salt electrochemical cell. Both the apparent potential and activity coefficient exhibited a strong dependence on concentration. A low concentration (0.69 mol %) of CsCl had no significant effect on the measured properties, while a higher concentration (1.40 mol %) of CsCl caused an increase (become more positive) in the apparent potential and activity coefficient at the higher range of LaCl{sub 3} concentrations.

  7. Effect of Side Chain Functional Group on Interactions in Ionic Liquid Systems: Insights from Infinite Dilution Thermodynamic Data.

    Science.gov (United States)

    Paduszyński, Kamil; Królikowska, Marta

    2017-11-02

    Measurements of infinite dilution activity coefficients of 48 molecular solutes (including alkanes, alkenes, alkynes, aromatics, ethers, alcohols, water, ketones, pyridine, thiophene, acetonitrile, and 1-nitropropane) in two ionic liquids (ILs), namely, 1-(2-hydroxyethyl)-3-methylimidazolium dicyanamide and 1-(2-chloroethyl)-3-methylimidazolium dicyanamide, are reported in the temperature range from T = 308.15 to 358.15 K. Comparative analysis of an effect of OH/Cl substitution of terminal carbon in side chains of imidazolium cations is presented and discussed in terms of different types of intermolecular forces acting between ILs and solutes. The new data also are confronted to those published previously for a "plain" counterpart of the studied ILs, namely, 1-ethyl-3-methylimidazolium dicyanamide. Infinite dilution capacity and selectivity of the studied ILs are presented to evaluate them as separating agents in extraction of aromatics from alkanes and sulfur compounds from alkanes. Three modeling approaches, namely, linear solvation energy relationship (LSER), regular solution theory, and conductor-like screening model for real solvents (COSMO-RS), are tested for their capabilities of capturing the substitution effects detected experimentally.

  8. Heat pulses in dilute 3He-4He mixtures

    International Nuclear Information System (INIS)

    Husson, L.P.J.

    1983-01-01

    The propagation of heat pulses in dilute 3 He- 4 He mixtures under pressure along a tube, which is long compared to its diameter, is discussed. At high temperatures, where the excitations are in local equilibrium with one another, the propagation of heat pulses in the liquid is determined by the phenomenon of second sound, which is essentially a density wave in the excitation gas. The velocity and attenuation of second sound can be determined from the shape of the transmitted pulse. Measurements on the scattering and absorption of phonons are presented, together with a detailed description of the experimental technique and the electronic equipment. Measurements on the velocity and absorption of second sound are presented. From the results for the velocity of second sound in pure 4 He, values of the phonon and roton parameters are deduced. The velocity data in the mixtures have been used to calculate values of the effective mass of 3 He in superfluid 4 He. The results of these calculations have been compared with values of the effective mass obtained by other authors. The coefficient of second-sound absorption in pure 4 He is computed from theory, making use of the phonon and roton parameters calculated from the second-sound velocity data in pure 4 He. The experimental results on the scattering and absorption of phonons have been analysed. The empirical expressions for the scattering and absorption rates obtained from the diffusive phonon signals were compared with the results of the Baym-Ebner theory, and have also been used to calculate the coefficient of thermal conductivity in dilute 3 He- 4 He mixtures. (Auth.)

  9. Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

    Science.gov (United States)

    Louvaris, Evangelos E.; Karnezi, Eleni; Kostenidou, Evangelia; Kaltsonoudis, Christos; Pandis, Spyros N.

    2017-10-01

    A method is developed following the work of Grieshop et al. (2009) for the determination of the organic aerosol (OA) volatility distribution combining thermodenuder (TD) and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA) produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a scanning mobility particle sizer (SMPS). In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60-75 % of the cooking OA (COA) at concentrations around 500 µg m-3 consisted of low-volatility organic compounds (LVOCs), 20-30 % of semivolatile organic compounds (SVOCs), and around 10 % of intermediate-volatility organic compounds (IVOCs). The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol-1 and the effective accommodation coefficient was 0.06-0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

  10. Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

    Directory of Open Access Journals (Sweden)

    E. E. Louvaris

    2017-10-01

    Full Text Available A method is developed following the work of Grieshop et al. (2009 for the determination of the organic aerosol (OA volatility distribution combining thermodenuder (TD and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a scanning mobility particle sizer (SMPS. In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60–75 % of the cooking OA (COA at concentrations around 500 µg m−3 consisted of low-volatility organic compounds (LVOCs, 20–30 % of semivolatile organic compounds (SVOCs, and around 10 % of intermediate-volatility organic compounds (IVOCs. The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol−1 and the effective accommodation coefficient was 0.06–0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

  11. Determination of the maximum inhibitory dilution of cetylpyridinium chloride-based mouthwashes against staphylococcus aureus: an in vitro study

    Directory of Open Access Journals (Sweden)

    Evandro Watanabe

    2008-08-01

    Full Text Available The aim of this in vitro study was to determine the maximum inhibitory dilution (MID of four cetylpyridinium chloride (CPC-based mouthwashes: CPC+Propolis, CPC+Malva, CPC+Eucaliptol+Juá+Romã+Propolis (Natural Honey® and CPC (Cepacol®, against 28 Staphylococcus aureus field strains, using the agar dilution method. Decimal dilutions ranging from 1/10 to 1/655,360 were prepared and added to Mueller Hinton Agar. Strains were inoculated using Steers multipoint inoculator. The inocula were seeded onto the surface of the culture medium in Petri dishes containing different dilutions of the mouthwashes. The dishes were incubated at 37ºC for 24 h. For readings, the MID was considered as the maximum dilution of mouthwash still capable of inhibiting microbial growth. The obtained data showed that CPC+Propolis had antimicrobial activity against 27 strains at 1/320 dilution and against all 28 strains at 1/160 dilution, CPC+Malva inhibited the growth of all 28 strains at 1/320 dilution, CPC+Eucaliptol+Juá+Romã+Propolis inhibited the growth of 2 strains at 1/640 dilution and all 28 strains at 1/320 dilution, and Cepacol® showed antimicrobial activity against 3 strains at 1/320 dilution and against all 28 strains at 1/160 dilution. Data were submitted to Kruskal-Wallis test, showing that the MID of Cepacol® was lower than that determined for the other products (p<0.05. In conclusion, CPC-mouthwashes showed antimicrobial activity against S. aureus and the addition of other substances to CPC improved its antimicrobial effect.

  12. The Truth About Ballistic Coefficients

    OpenAIRE

    Courtney, Michael; Courtney, Amy

    2007-01-01

    The ballistic coefficient of a bullet describes how it slows in flight due to air resistance. This article presents experimental determinations of ballistic coefficients showing that the majority of bullets tested have their previously published ballistic coefficients exaggerated from 5-25% by the bullet manufacturers. These exaggerated ballistic coefficients lead to inaccurate predictions of long range bullet drop, retained energy and wind drift.

  13. Composite systems of dilute and dense couplings

    International Nuclear Information System (INIS)

    Raymond, J R; Saad, D

    2008-01-01

    Composite systems, where couplings are of two types, a combination of strong dilute and weak dense couplings of Ising spins, are examined through the replica method. The dilute and dense parts are considered to have independent canonical disordered or uniform bond distributions; mixing the models by variation of a parameter γ alongside inverse temperature β we analyse the respective thermodynamic solutions. We describe the variation in high temperature transitions as mixing occurs; in the vicinity of these transitions we exactly analyse the competing effects of the dense and sparse models. By using the replica symmetric ansatz and population dynamics we described the low temperature behaviour of mixed systems

  14. Computer automation of a dilution cryogenic system

    International Nuclear Information System (INIS)

    Nogues, C.

    1992-09-01

    This study has been realized in the framework of studies on developing new technic for low temperature detectors for neutrinos and dark matter. The principles of low temperature physics and helium 4 and dilution cryostats, are first reviewed. The cryogenic system used and the technic for low temperature thermometry and regulation systems are then described. The computer automation of the dilution cryogenic system involves: numerical measurement of the parameter set (pressure, temperature, flow rate); computer assisted operating of the cryostat and the pump bench; numerical regulation of pressure and temperature; operation sequence full automation allowing the system to evolve from a state to another (temperature descent for example)

  15. Dilution refrigeration with multiple mixing chambers

    International Nuclear Information System (INIS)

    Coops, G.M.

    1981-01-01

    A dilution refrigerator is an instrument to reach temperatures in the mK region in a continuous way. The temperature range can be extended and the cooling power can be enlarged by adding an extra mixing chamber. In this way we obtain a double mixing chamber system. In this thesis the theory of the multiple mixing chamber is presented and tested on its validity by comparison with the measurements. Measurements on a dilution refrigerator with a circulation rate up to 2.5 mmol/s are also reported. (Auth.)

  16. Diluted magnetic semiconductor nanowires exhibiting magnetoresistance

    Science.gov (United States)

    Yang, Peidong [El Cerrito, CA; Choi, Heonjin [Seoul, KR; Lee, Sangkwon [Daejeon, KR; He, Rongrui [Albany, CA; Zhang, Yanfeng [El Cerrito, CA; Kuykendal, Tevye [Berkeley, CA; Pauzauskie, Peter [Berkeley, CA

    2011-08-23

    A method for is disclosed for fabricating diluted magnetic semiconductor (DMS) nanowires by providing a catalyst-coated substrate and subjecting at least a portion of the substrate to a semiconductor, and dopant via chloride-based vapor transport to synthesize the nanowires. Using this novel chloride-based chemical vapor transport process, single crystalline diluted magnetic semiconductor nanowires Ga.sub.1-xMn.sub.xN (x=0.07) were synthesized. The nanowires, which have diameters of .about.10 nm to 100 nm and lengths of up to tens of micrometers, show ferromagnetism with Curie temperature above room temperature, and magnetoresistance up to 250 Kelvin.

  17. Isopiestic determination of the osmotic and activity coefficients of the {l_brace}yKCl + (1 - y)K{sub 2}HPO{sub 4}{r_brace}(aq) system at T = 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, Daniela Z. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 001 Belgrade (Serbia); Miladinovic, Jelena, E-mail: duma@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 001 Belgrade (Serbia); Todorovic, Milica D.; Zrilic, Milorad M. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 001 Belgrade (Serbia); Rard, Joseph A., E-mail: solution_chemistry2@comcast.net [4363 Claremont Way, Livermore, CA 94550 (United States)

    2011-12-15

    Highlights: > Isopiestic measurements were made for {l_brace}yKCl + (1 - y)K{sub 2}HPO{sub 4}{r_brace}(aq) at T = 298.15 K. > The resulting osmotic coefficients were represented by three thermodynamic models. > Activity coefficients from Pitzer model with Scatchard mixing terms are recommended. - Abstract: The osmotic coefficients of aqueous mixtures of KCl and K{sub 2}HPO{sub 4} have been measured at T = (298.15 {+-} 0.01) K by the isopiestic vapor pressure method over the range of ionic strengths from (2.3700 to 11.250) mol . kg{sup -1} using CaCl{sub 2}(aq) as the reference solution. Our new experimental results were modeled with an extended form of Pitzer's ion-interaction model equations, both with the usual mixing terms and with Scatchard's neutral-electrolyte mixing terms, and with the Clegg-Pitzer-Brimblecombe equations based on the mole-fraction-composition scale. There is a dearth of previously published isopiestic data for mixtures containing salts of HPO{sub 4}{sup 2-}(aq) and, consequently, no previous measurements are available for comparison with the present results. The present study yields Cl{sup -}HPO{sub 4}{sup 2-} mixing parameters for these three models that are needed for modeling the thermodynamic activities of solute components of natural waters and other complex aqueous electrolyte mixtures.

  18. Osmotic and activity coefficients of {l_brace}y Na{sub 2}SO{sub 4} + (1 - y) ZnSO{sub 4}{r_brace}(aq) at T = 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Marjanovic, V. [High Technical School, Trg Svetog Save 34, 31 000 Uzice (Serbia and Montenegro); Ninkovic, R. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia and Montenegro); Miladinovic, J. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia and Montenegro)]. E-mail: duma@elab.tmf.bg.ac.yu; Todorovic, M. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia and Montenegro); Pavicevic, V. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia and Montenegro)

    2005-02-01

    The osmotic coefficients of the mixed electrolyte solution {l_brace}y Na{sub 2}SO{sub 4} + (1 - y) ZnSO{sub 4}{r_brace}(aq) have been measured by the isopiestic method, at T = 298.5 K. The experimental results were treated by Scatchard's, Pitzer-Kim's and Clegg-Pitzer-Brimblecombe's methods for mixed-electrolyte solutions. By these methods, the activity coefficients for Na{sub 2}SO{sub 4} and ZnSO{sub 4} were calculated and compared. The Scatchard interaction parameters are used for calculation of the excess Gibbs free energy as a function of ionic strength and ionic-strength fraction of Na{sub 2}SO{sub 4}. Also, the Zdanovskii's rule of linearity is tested.

  19. Aluminium. II - A review of deformation properties of high purity aluminium and dilute aluminium alloys.

    Science.gov (United States)

    Reed, R. P.

    1972-01-01

    The elastic and plastic deformation behavior of high-purity aluminum and of dilute aluminum alloys is reviewed. Reliable property data, including elastic moduli, elastic coefficients, tensile, creep, fatigue, hardness, and impact are presented. Single crystal tensile results are discussed. Rather comprehensive reference lists, containing publications of the past 20 years, are included for each of the above categories. Defect structures and mechanisms responsible for mechanical behavior are presented. Strengthening techniques (alloys, cold work, irradiation, quenching, composites) and recovery are briefly reviewed.

  20. On the attenuation of x-rays and gamma-rays in dilute solutions

    DEFF Research Database (Denmark)

    Gerward, Leif

    1996-01-01

    The theory of X-ray and gamma-ray attenuation in solutions is developed. The rule of mixture for the calculation of mass and linear attenuation coefficients is elaborated in the general case as well as in the limit of extreme dilution. The validity of the latter approximation is illustrated...... by the attenuation of 17.443 keV X-rays in aqueous solutions of NaCl. Copyright (C) 1996 Elsevier Science Ltd...

  1. Quantifying dilution caused by execution efficiency

    Directory of Open Access Journals (Sweden)

    Taís Renata Câmara

    Full Text Available Abstract In open pit mining, dilution is not always a factor systematically analyzed and calculated. Often it is only an adjusted number, for example, calculated or even empirically determined for a certain operational condition perpetuating along time in the form of a constant applied to calculating reserves or mine planning in attendance of audit requirements. Dilution and loss are factors that should be always considered for tonnage and grade estimates. These factors are always associated and can be determined considering several particularities of the deposit and the operation itself. In this study, a methodology was determined to identify blocks adjacent to the blocks previously planned to be mined. Thus, it is possible to estimate the dilution caused by poor operating efficiency, taking into account the inability of the equipment to perfectly remove each block, respecting its limits. Mining dilution is defined as the incorporation of waste material to ore due to the operational incapacity to efficiently separate the materials during the mining process, considering the physical processes, and the operating and geometric configurations of the mining with the equipment available.

  2. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    be attributed to the reliability of the measured distances which fall off quickly with each shell. Therefore, in ... field and electrical field gradients due to impurities in vanadium [13]. The effective .... Expanding ∆φ(| Rn' |) in power series of u(R0 n), one gets ... The results of each dilute alloy system are presented separately and ...

  3. A century of indicator dilution technique

    DEFF Research Database (Denmark)

    Henriksen, Jens H; Jensen, Gorm B; Larsson, Henrik B W

    2014-01-01

    This review imparts the history and the present status of the indicator dilution technique with quantitative bolus injection. The first report on flow measurement with this technique appeared 100 years ago. In 1928, the use of intravascular dyes made possible a widespread application in animals...

  4. Liquid volumes measurements by isotopic dilution

    International Nuclear Information System (INIS)

    Herrera M, J.M.

    1981-01-01

    By the nuclear technique, isotopic dilution industrial liquid volumes may be measured in large size recipients of irregular shapes using radiotracers. In the present work laboratory and pilot test are made with 2 radiotracers for optimizing the technique and later done on an industrial scale, obtaining a maximum deviation of +-2%, some recommendations are given to improve the performance of the technique. (author)

  5. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    We present here a systematic investigation of the atomic displacements in bcc transition metal (TM) dilute alloys. We have calculated the atomic displacements in bcc (V, Cr, Fe, Nb, Mo, Ta and W) transition metals (TMs) due to 3d, 4d and 5d TMs at the substitutional site using the Kanzaki lattice static method. Wills and ...

  6. Continuous deionization of a dilute nickel solution

    NARCIS (Netherlands)

    Spoor, P.B.; Koene, L.; Veen, ter W.R.; Janssen, L.J.J.

    2002-01-01

    This paper describes the continuous removal of nickel ions from a dilute solution using a hybrid ion-exchange/electrodialysis process. Emphasis was placed on the ionic state of the bed during the process, and the mass balance of ions in the system. Much of this information was obtained by analysing

  7. Dilution kicker for the SPS beam dump

    CERN Multimedia

    1974-01-01

    In order to reduce thermal stress on the SPS dump material, the fast-ejected beam was swept horizontally across the dump. This was done with the "dilution kicker" MKDH, still in use at the time of writing. The person on the left is Manfred Mayer. See also 7404072X.

  8. Magnetic properties of diluted magnetic semiconductors

    NARCIS (Netherlands)

    Jonge, de W.J.M.; Swagten, H.J.M.

    1991-01-01

    A review will be given of the magnetic characteristics of diluted magnetic semiconductors and the relation with the driving exchange mechanisms. II–VI as well as IV–VI compounds will be considered. The relevance of the long-range interaction and the role of the carrier concentration will be

  9. Correlation between octanol/water and liposome/water distribution coefficients and drug absorption of a set of pharmacologically active compounds.

    Science.gov (United States)

    Esteves, Freddy; Moutinho, Carla; Matos, Carla

    2013-06-01

    Absorption and consequent therapeutic action are key issues in the development of new drugs by the pharmaceutical industry. In this sense, different models can be used to simulate biological membranes to predict the absorption of a drug. This work compared the octanol/water and the liposome/water models. The parameters used to relate the two models were the distribution coefficients between liposomes and water and octanol and water and the fraction of drug orally absorbed. For this study, 66 drugs were collected from literature sources and divided into four groups according to charge and ionization degree: neutral; positively charged; negatively charged; and partially ionized/zwitterionic. The results show a satisfactory linear correlation between the octanol and liposome systems for the neutral (R²= 0.9324) and partially ionized compounds (R²= 0.9367), contrary to the positive (R²= 0.4684) and negatively charged compounds (R²= 0.1487). In the case of neutral drugs, results were similar in both models because of the high fraction orally absorbed. However, for the charged drugs (positively, negatively, and partially ionized/zwitterionic), the liposomal model has a more-appropriate correlation with absorption than the octanol model. These results show that the neutral compounds only interact with membranes through hydrophobic bonds, whereas charged drugs favor electrostatic interactions established with the liposomes. With this work, we concluded that liposomes may be a more-appropriate biomembrane model than octanol for charged compounds.

  10. Optical absorption of dilute solutions of metals in molten salts

    Energy Technology Data Exchange (ETDEWEB)

    Senatore, G.; Parrinello, M.; Tosi, M.P. (Trieste Univ. (Italy). Ist. di Fisica Teorica; Gruppo Nazionale di Struttura dell material del CNR, Trieste (Italy); International Centre for Theoretical Physics, Trieste (Italy))

    1978-12-23

    The theory of liquid structure for fluids of charged hard spheres is applied to an evaluation of the F-centre model for valence electrons in metal-molten salt solutions at high dilution. Minimization of the free energy yields the groundstate radius of the elctron bubble and hence the optical excitation energy in a Franck-Condon transition, the shift and broadening of the transition due to fluctuations in the bubble radius, the volume of mixing, and the activity of the salt in the solution.

  11. On the Kendall Correlation Coefficient

    OpenAIRE

    Stepanov, Alexei

    2015-01-01

    In the present paper, we first discuss the Kendall rank correlation coefficient. In continuous case, we define the Kendall rank correlation coefficient in terms of the concomitants of order statistics, find the expected value of the Kendall rank correlation coefficient and show that the later is free of n. We also prove that in continuous case the Kendall correlation coefficient converges in probability to its expected value. We then propose to consider the expected value of the Kendall rank ...

  12. Thermodynamics of dilute aqueous solutions of imidazolium based ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Tejwant [Salt and Marine Chemicals Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364002 (India); Kumar, Arvind, E-mail: arvind@csmcri.or [Salt and Marine Chemicals Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364002 (India)

    2011-06-15

    Research highlights: The thermodynamic behaviour of aqueous imidazolium ILs has been investigated. Volumetric and ultrasonic results indicated the hydrophobic hydration of ILs. Viscometric studies revealed studied ionic liquids as water-structure makers. Hydration number increased with increase in alkyl chain length of the cation. - Abstract: Experimental measurements of density {rho}, speed of sound u, and viscosity {eta} of aqueous solutions of various 1-alkyl-3-methylimidazolium based ionic liquid (IL) solutions have been performed in dilute concentration regime at 298.15 K to get insight into hydration behaviour of ILs. The investigated ILs are based on 1-alkyl-3-methylimidazolium cation, [C{sub n}mim] having [BF{sub 4}]{sup -}, [Cl]{sup -}, [C{sub 1}OSO{sub 3}]{sup -}, and [C{sub 8}OSO{sub 3}]{sup -} as anions where n = 4 or 8. Several thermodynamic parameters like apparent molar volume {phi}{sub V}, isentropic compressibility {beta}{sub s}, and viscosity B-coefficients have been derived from experimental data. Limiting value of apparent molar volume has been discussed in terms of intrinsic molar volume (V{sub int}) molar electrostriction volume (V{sub elec}), molar disordered (V{sub dis}), and cage volume (V{sub cage}). Viscosity B-coefficients have been used to quantify the kosmotropic or chaotropic nature of ILs. Hydration number of ILs obtained using elctrostriction volume, isentropic compressibility, viscosity, and differential scanning calorimetry have been found to be comparative within the experimental error. The hydrophobic hydration has found to play an important role in hydration of ILs as compared to hydration due to hydrogen bonding and electrostriction. Limiting molar properties, hydration numbers, and B-coefficients have been discussed in terms of alkyl chain length of cation or nature of anion.

  13. Thermodynamics of dilute aqueous solutions of imidazolium based ionic liquids

    International Nuclear Information System (INIS)

    Singh, Tejwant; Kumar, Arvind

    2011-01-01

    Research highlights: → The thermodynamic behaviour of aqueous imidazolium ILs has been investigated. → Volumetric and ultrasonic results indicated the hydrophobic hydration of ILs. → Viscometric studies revealed studied ionic liquids as water-structure makers. → Hydration number increased with increase in alkyl chain length of the cation. - Abstract: Experimental measurements of density ρ, speed of sound u, and viscosity η of aqueous solutions of various 1-alkyl-3-methylimidazolium based ionic liquid (IL) solutions have been performed in dilute concentration regime at 298.15 K to get insight into hydration behaviour of ILs. The investigated ILs are based on 1-alkyl-3-methylimidazolium cation, [C n mim] having [BF 4 ] - , [Cl] - , [C 1 OSO 3 ] - , and [C 8 OSO 3 ] - as anions where n = 4 or 8. Several thermodynamic parameters like apparent molar volume φ V , isentropic compressibility β s , and viscosity B-coefficients have been derived from experimental data. Limiting value of apparent molar volume has been discussed in terms of intrinsic molar volume (V int ) molar electrostriction volume (V elec ), molar disordered (V dis ), and cage volume (V cage ). Viscosity B-coefficients have been used to quantify the kosmotropic or chaotropic nature of ILs. Hydration number of ILs obtained using elctrostriction volume, isentropic compressibility, viscosity, and differential scanning calorimetry have been found to be comparative within the experimental error. The hydrophobic hydration has found to play an important role in hydration of ILs as compared to hydration due to hydrogen bonding and electrostriction. Limiting molar properties, hydration numbers, and B-coefficients have been discussed in terms of alkyl chain length of cation or nature of anion.

  14. Phase diagrams of diluted transverse Ising nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Bouhou, S.; Essaoudi, I. [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Ainane, A., E-mail: ainane@pks.mpg.de [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38 D-01187 Dresden (Germany); Saber, M. [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38 D-01187 Dresden (Germany); Ahuja, R. [Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden); Dujardin, F. [Laboratoire de Chimie et Physique des Milieux Complexes (LCPMC), Institut de Chimie, Physique et Matériaux (ICPM), 1 Bd. Arago, 57070 Metz (France)

    2013-06-15

    In this paper, the phase diagrams of diluted Ising nanowire consisting of core and surface shell coupling by J{sub cs} exchange interaction are studied using the effective field theory with a probability distribution technique, in the presence of transverse fields in the core and in the surface shell. We find a number of characteristic phenomena. In particular, the effect of concentration c of magnetic atoms, the exchange interaction core/shell, the exchange in surface and the transverse fields in core and in surface shell of phase diagrams are investigated. - Highlights: ► We use the EFT to investigate the phase diagrams of Ising transverse nanowire. ► Ferrimagnetic and ferromagnetic cases are investigated. ► The effects of the dilution and the transverse fields in core and shell are studied. ► Behavior of the transition temperature with the exchange interaction is given.

  15. Phase diagrams of diluted transverse Ising nanowire

    International Nuclear Information System (INIS)

    Bouhou, S.; Essaoudi, I.; Ainane, A.; Saber, M.; Ahuja, R.; Dujardin, F.

    2013-01-01

    In this paper, the phase diagrams of diluted Ising nanowire consisting of core and surface shell coupling by J cs exchange interaction are studied using the effective field theory with a probability distribution technique, in the presence of transverse fields in the core and in the surface shell. We find a number of characteristic phenomena. In particular, the effect of concentration c of magnetic atoms, the exchange interaction core/shell, the exchange in surface and the transverse fields in core and in surface shell of phase diagrams are investigated. - Highlights: ► We use the EFT to investigate the phase diagrams of Ising transverse nanowire. ► Ferrimagnetic and ferromagnetic cases are investigated. ► The effects of the dilution and the transverse fields in core and shell are studied. ► Behavior of the transition temperature with the exchange interaction is given

  16. Isotope dilution analysis of environmental samples

    International Nuclear Information System (INIS)

    Tolgyessy, J.; Lesny, J.; Korenova, Z.; Klas, J.; Klehr, E.H.

    1986-01-01

    Isotope dilution analysis has been used for the determination of several trace elements - especially metals - in a variety of environmental samples, including aerosols, water, soils, biological materials and geological materials. Variations of the basic concept include classical IDA, substoichiometric IDA, and more recently, sub-superequivalence IDA. Each variation has its advantages and limitations. A periodic chart has been used to identify those elements which have been measured in environmental samples using one or more of these methods. (author)

  17. Fractal effects on excitations in diluted ferromagnets

    International Nuclear Information System (INIS)

    Kumar, D.

    1981-08-01

    The low energy spin-wave like excitations in diluted ferromagnets near percolation threshold are studied. For this purpose an explicit use of the fractal model for the backbone of the infinite percolating cluster due to Kirkpatrick is made. Three physical effects are identified, which cause the softening of spin-waves as the percolation point is approached. The importance of fractal effects in the calculation of density of states and the low temperature thermodynamics is pointed out. (author)

  18. Molecular analysis of two mouse dilute locus deletion mutations: Spontaneous dilute lethal20J and radiation-induced dilute prenatal lethal Aa2 alleles

    International Nuclear Information System (INIS)

    Strobel, M.C.; Seperack, P.K.; Copeland, N.G.; Jenkins, N.A.

    1990-01-01

    The dilute (d) coat color locus of mouse chromosome 9 has been identified by more than 200 spontaneous and mutagen-induced recessive mutations. With the advent of molecular probes for this locus, the molecular lesion associated with different dilute alleles can be recognized and precisely defined. In this study, two dilute mutations, dilute-lethal20J (dl20J) and dilute prenatal lethal Aa2, have been examined. Using a dilute locus genomic probe in Southern blot analysis, we detected unique restriction fragments in dl20J and Aa2 DNA. Subsequent analysis of these fragments showed that they represented deletion breakpoint fusion fragments. DNA sequence analysis of each mutation-associated deletion breakpoint fusion fragment suggests that both genomic deletions were generated by nonhomologous recombination events. The spontaneous dl20J mutation is caused by an interstitial deletion that removes a single coding exon of the dilute gene. The correlation between this discrete deletion and the expression of all dilute-associated phenotypes in dl20J homozygotes defines the dl20J mutation as a functional null allele of the dilute gene. The radiation-induced Aa2 allele is a multilocus deletion that, by complementation analysis, affects both the dilute locus and the proximal prenatal lethal-3 (pl-3) functional unit. Molecular analysis of the Aa2 deletion breakpoint fusion fragment has provided access to a previously undefined gene proximal to d. Initial characterization of this new gene suggests that it may represent the genetically defined pl-3 functional unit

  19. A report on the aquatic dilution experiment carried out at discharge canal, KGS site

    International Nuclear Information System (INIS)

    Reji, T.K.; Nayak, P.D.; Sudhakar, J.; Ajith, T.L.; Vishnu, M.S.; Ravi, P.M.; James, J.P.; Joshi, R.M.; Naik, S.B.; Kudtharkar, A.M.; Gaonkar, S.M.; Verma, P.C.; Datta, D.; Dahiya, Sudhir; Brijkumar; Datta, Maduparna; Sajeevan, G.

    2009-08-01

    Under Nuclear Power Corporation of India Limited (NPCIL), three units of (each of capacity 220MWe) Nuclear Power Stations are operational and one unit of similar capacity is under advanced stage of construction at Kaiga site. The radioactive liquid effluents generated in the plant are diluted with Condenser Coolant Water Stream (CCW) which is then discharged into Kadra reservoir through an artificially made discharge canal. The basic objective of the present study is to estimate the Dilution Factors at various locations of discharge canal and to understand the process of dilution and dispersion of radioactive effluent in the discharge canal. The strategy of the experiment involved the collection of samples from discharge canal lengthwise, breadth wise and depth wise immediately after the routine release of one of the batches of effluent stream into the CCW stream. No additional activity was released for the purpose of this experiment. The study compared the experimentally obtained Dilution Factor with that calculated based on the flow rates of CCW pumps and active liquid effluent discharge pumps. In the present conditions of experiment, Dilution Factor, based on flow rates of CCW pumps and Liquid Effluent Discharge pump, works out to be 8.11 E -05 while experimentally observed Mean Dilution Factor in the discharge canal works out to be (7.75±2.15) E-05. Hence this experiment clearly demonstrate the validity of the method of calculating dilution factor based on the flow rates of CCW line and that of Effluent discharge pump. The data analysis indicates that mass flow seems to be the major process of dispersion in the discharge canal. The tritium activity was found to be moving faster in the midstream as compared to that near the shore. The conclusions are drawn purely based on experimental results. This experimental data can be used for validation of aquatic dispersion models. (author)

  20. Developments on drug discovery and on new therapeutics: highly diluted tinctures act as biological response modifiers.

    Science.gov (United States)

    de Oliveira, Carolina C; Abud, Ana Paula R; de Oliveira, Simone M; Guimarães, Fernando de S F; de Andrade, Lucas F; Di Bernardi, Raffaello P; Coletto, Ediely L de O; Kuczera, Diogo; Da Lozzo, Eneida J; Gonçalves, Jenifer P; Trindade, Edvaldo da S; Buchi, Dorly de F

    2011-10-26

    In the search for new therapies novel drugs and medications are being discovered, developed and tested in laboratories. Highly diluted substances are intended to enhance immune system responses resulting in reduced frequency of various diseases, and often present no risk of serious side-effects due to its low toxicity. Over the past years our research group has been investigating the action of highly diluted substances and tinctures on cells from the immune system. We have developed and tested several highly diluted tinctures and here we describe the biological activity of M1, M2, and M8 both in vitro in immune cells from mice and human, and in vivo in mice. Cytotoxicity, cytokines released and NF-κB activation were determined after in vitro treatment. Cell viability, oxidative response, lipid peroxidation, bone marrow and lymph node cells immunophenotyping were accessed after mice in vivo treatment. None of the highly diluted tinctures tested were cytotoxic to macrophages or K562. Lipopolysaccharide (LPS)-stimulated macrophages treated with all highly diluted tinctures decreased tumour necrosis factor alpha (TNF-α) release and M1, and M8 decreased IFN-γ production. M1 has decreased NF-κB activity on TNF-α stimulated reporter cell line. In vivo treatment lead to a decrease in reactive oxygen species (ROS), nitric oxide (NO) production was increased by M1, and M8, and lipid peroxidation was induced by M1, and M2. All compounds enhanced the innate immunity, but M1 also augmented acquired immunity and M2 diminished B lymphocytes, responsible to acquired immunity. Based on the results presented here, these highly diluted tinctures were shown to modulate immune responses. Even though further investigation is needed there is an indication that these highly diluted tinctures could be used as therapeutic interventions in disorders where the immune system is compromised.

  1. Developments on drug discovery and on new therapeutics: highly diluted tinctures act as biological response modifiers

    Directory of Open Access Journals (Sweden)

    de Oliveira Carolina C

    2011-10-01

    Full Text Available Abstract Background In the search for new therapies novel drugs and medications are being discovered, developed and tested in laboratories. Highly diluted substances are intended to enhance immune system responses resulting in reduced frequency of various diseases, and often present no risk of serious side-effects due to its low toxicity. Over the past years our research group has been investigating the action of highly diluted substances and tinctures on cells from the immune system. Methods We have developed and tested several highly diluted tinctures and here we describe the biological activity of M1, M2, and M8 both in vitro in immune cells from mice and human, and in vivo in mice. Cytotoxicity, cytokines released and NF-κB activation were determined after in vitro treatment. Cell viability, oxidative response, lipid peroxidation, bone marrow and lymph node cells immunophenotyping were accessed after mice in vivo treatment. Results None of the highly diluted tinctures tested were cytotoxic to macrophages or K562. Lipopolysaccharide (LPS-stimulated macrophages treated with all highly diluted tinctures decreased tumour necrosis factor alpha (TNF-α release and M1, and M8 decreased IFN-γ production. M1 has decreased NF-κB activity on TNF-α stimulated reporter cell line. In vivo treatment lead to a decrease in reactive oxygen species (ROS, nitric oxide (NO production was increased by M1, and M8, and lipid peroxidation was induced by M1, and M2. All compounds enhanced the innate immunity, but M1 also augmented acquired immunity and M2 diminished B lymphocytes, responsible to acquired immunity. Conclusions Based on the results presented here, these highly diluted tinctures were shown to modulate immune responses. Even though further investigation is needed there is an indication that these highly diluted tinctures could be used as therapeutic interventions in disorders where the immune system is compromised.

  2. Relative volatility of dilute solutions of Rb-Cs system

    International Nuclear Information System (INIS)

    Gromov, P.B.; Izotov, V.P.; Nisel'son, L.A.

    1984-01-01

    Relative volatility of diluted solutions Rb-Cs in the temperature range 650-820 K and pressures 13-200 gPa has been studied. The system Rb-Cs in the range of diluted solutions obeys the Henry law. It is shown, that liquid-vapour equilibrium in diluted solutions of cesium in rubidium is characterized by negative deviation from perfection

  3. Drag Coefficient Estimation in Orbit Determination

    Science.gov (United States)

    McLaughlin, Craig A.; Manee, Steve; Lichtenberg, Travis

    2011-07-01

    Drag modeling is the greatest uncertainty in the dynamics of low Earth satellite orbits where ballistic coefficient and density errors dominate drag errors. This paper examines fitted drag coefficients found as part of a precision orbit determination process for Stella, Starlette, and the GEOSAT Follow-On satellites from 2000 to 2005. The drag coefficients for the spherical Stella and Starlette satellites are assumed to be highly correlated with density model error. The results using MSIS-86, NRLMSISE-00, and NRLMSISE-00 with dynamic calibration of the atmosphere (DCA) density corrections are compared. The DCA corrections were formulated for altitudes of 200-600 km and are found to be inappropriate when applied at 800 km. The yearly mean fitted drag coefficients are calculated for each satellite for each year studied. The yearly mean drag coefficients are higher for Starlette than Stella, where Starlette is at a higher altitude. The yearly mean fitted drag coefficients for all three satellites decrease as solar activity decreases after solar maximum.

  4. The activity of {gamma}-emitters as measured by ionisation chambers the determination of the specific emission coefficient {gamma} for some radio-elements (1961); Mesure de l'activite des emetteurs {gamma} par chambre d'ionisation. Determination du coefficient specifique d'emission {gamma} de quelques radioelements (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Engelmann, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-06-15

    The object of this work is to study techniques of measurement using the gamma ionisation chamber, making it possible either to measure the activities of radioactive sources, or to determine the specific emission coefficient {gamma} (or the coefficient K) of a given radioelement. The ionisation chambers studied belong to two categories: graphites cavity-chambers, and 4 {pi} {gamma} chambers. For the cavity-chamber measurements, the different correction factors of which account must be taken have been calculated, in particular the geometric and hygrometric corrections. The absorption and auto-absorption corrections have led to the introduction of the notion of the 'effective energy {gamma}' of a radioelement. In the case of 4 {pi} {gamma} chambers, it has been shown that appropriately shaped electrodes make it possible to improve their performances. One of the chambers described permits the measurement of {beta} emitters using the associated Bremsstrahlung. In order to measure the K coefficient of some radioelements, it has been found useful a 4 {pi} {gamma} chamber with graphite walls, the measurement being carried out by comparison with a radium standard. The validity of the method was checked with radioelements for whom the K coefficient values are well-known ({sup 24}Na, {sup 60}Co, {sup 131}I, {sup 198}Au). For other radioelements, the following values were obtained (expressed in r cm{sup 3} mc{sup -1} h{sup -1}): {sup 51}Cr: 0,18; {sup 56}Mn: 8,8; {sup 65}Zn: 3,05; {sup 124}Sb: 9,9; {sup 134}Cs: 9,3; {sup 137}Cs: 3,35; {sup 141}Ce: 0,46; {sup 170}Tm: 0,023; {sup 192}Ir: 24,9; {sup 203}Hg: 1,18; These values have been corrected for the contribution to the dose of the fluorescent radiation which may be emitted by the source, except in the case of Tm{sup 170}. In the last part of this work, the performances of the different electro-metric devices used were compared. (author) [French] Le but de ce travail est d'etudier les techniques de mesure par

  5. The activity of {gamma}-emitters as measured by ionisation chambers the determination of the specific emission coefficient {gamma} for some radio-elements (1961); Mesure de l'activite des emetteurs {gamma} par chambre d'ionisation. Determination du coefficient specifique d'emission {gamma} de quelques radioelements (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Engelmann, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-06-15

    The object of this work is to study techniques of measurement using the gamma ionisation chamber, making it possible either to measure the activities of radioactive sources, or to determine the specific emission coefficient {gamma} (or the coefficient K) of a given radioelement. The ionisation chambers studied belong to two categories: graphites cavity-chambers, and 4 {pi} {gamma} chambers. For the cavity-chamber measurements, the different correction factors of which account must be taken have been calculated, in particular the geometric and hygrometric corrections. The absorption and auto-absorption corrections have led to the introduction of the notion of the 'effective energy {gamma}' of a radioelement. In the case of 4 {pi} {gamma} chambers, it has been shown that appropriately shaped electrodes make it possible to improve their performances. One of the chambers described permits the measurement of {beta} emitters using the associated Bremsstrahlung. In order to measure the K coefficient of some radioelements, it has been found useful a 4 {pi} {gamma} chamber with graphite walls, the measurement being carried out by comparison with a radium standard. The validity of the method was checked with radioelements for whom the K coefficient values are well-known ({sup 24}Na, {sup 60}Co, {sup 131}I, {sup 198}Au). For other radioelements, the following values were obtained (expressed in r cm{sup 3} mc{sup -1} h{sup -1}): {sup 51}Cr: 0,18; {sup 56}Mn: 8,8; {sup 65}Zn: 3,05; {sup 124}Sb: 9,9; {sup 134}Cs: 9,3; {sup 137}Cs: 3,35; {sup 141}Ce: 0,46; {sup 170}Tm: 0,023; {sup 192}Ir: 24,9; {sup 203}Hg: 1,18; These values have been corrected for the contribution to the dose of the fluorescent radiation which may be emitted by the source, except in the case of Tm{sup 170}. In the last part of this work, the performances of the different electro-metric devices used were compared. (author) [French] Le but de ce travail est d'etudier les techniques de mesure par chambre d

  6. A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Yan Pan; Rong-shi Cheng

    2000-01-01

    The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration Cs (dynamic contact concentration) which divides the dilute polymer solution into two regions.

  7. Activity concentration of 210Po and 210Pb, its contribution to the radiation dose and distribution coefficient in aquatic ecosystem of major rivers of coastal Karnataka

    International Nuclear Information System (INIS)

    Rajashekara, K.M.; Prakash, V.; Narayana, Y.

    2013-01-01

    Rivers are the major pathways for the transport of weathered materials from the land to the oceans. The geochemical studies on river waters provide an insight into the weathering process that control the distribution of elements in dissolved and particulate phases and their fluxes to the estuaries. Concentrations of natural series radionuclide in fresh water bodies are liable to be much more variable than those in the marine environment since they are heavily influenced by the local geochemistry of the watershed. The concentrations of radioactive materials vary from region to region and this variation is found to be significantly high in some areas. Some of the regions are rich with the flow of major rivers and estuaries of these rivers, and investigations of these riverine and estuarine aquatic environments would throw light on the transportation, distribution and enrichment mechanism of radionuclides. In this context, the activity of 210 Po and 210 Pb were measured in different matrices of aquatic ecosystem of the major rivers namely, Kali, Sharavathi and Netravathi river of Coastal Karnataka

  8. A conductance study of guanidinium chloride, thiocyanate, sulfate, and carbonate in dilute aqueous solutions: ion-association and carbonate hydrolysis effects.

    Science.gov (United States)

    Hunger, Johannes; Neueder, Roland; Buchner, Richard; Apelblat, Alexander

    2013-01-17

    We study the conductance of dilute aqueous solutions for a series of guandinium salts at 298.15 K. The experimental molar conductivities were analyzed within the framework of the Quint-Viallard theory in combination with Debye-Hückel activity coefficients. From this analysis, we find no evidence for significant ion association in aqueous solutions of guanidinium chloride (GdmCl) and guanidinium thiocyanate (GdmSCN), and the molar conductivity of these electrolytes can be modeled assuming a complete dissociation. The limiting ionic conductivity of the guanidinium ion (Gdm(+)) is accurately determined to λ(Gdm(+)) = 51.45 ± 0.10 S cm(2) mol(-1). For the bivalent salts guanidinium sulfate (Gdm(2)SO(4)) and guanidinium carbonate (Gdm(2)CO(3)), the molar conductivities show small deviations from ideal (fully dissociated electrolyte) behavior, which are related to weak ion association in solution. Furthermore, for solutions of Gdm(2)CO(3), the hydrolysis of the carbonate anion leads to distinctively increased molar conductivities at high dilutions. The observed ion association is rather weak for all studied electrolytes and cannot explain the different protein denaturing activities of the studied guanidinium salts, as has been proposed previously.

  9. Quadrature formulas for Fourier coefficients

    KAUST Repository

    Bojanov, Borislav

    2009-09-01

    We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives. © 2009 Elsevier B.V. All rights reserved.

  10. Predictive performance of the human Cell Line Activation Test (h-CLAT) for lipophilic chemicals with high octanol-water partition coefficients.

    Science.gov (United States)

    Takenouchi, Osamu; Miyazawa, Masaaki; Saito, Kazutoshi; Ashikaga, Takao; Sakaguchi, Hitoshi

    2013-01-01

    To meet the urgent need for a reliable alternative test for predicting skin sensitizing potential of many chemicals, we have developed a cell-based in vitro test, human Cell Line Activation Test (h-CLAT). However, the predictive performance for lipophilic chemicals in the h-CLAT still remains relatively unknown. Moreover, it's suggested that low water solubility of chemicals might induce false negative outcomes. Thus, in this study, we tested relatively low water soluble 37 chemicals with log Kow values above and below 3.5 in the h-CLAT. The small-scale assessment resulted in nine false negative outcomes for chemicals with log Kow values greater than 3.5. We then created a dataset of 143 chemicals by combining the existing dataset of 106 chemicals and examined the predictive performance of the h-CLAT for chemicals with a log Kow of less than 3.5; a total of 112 chemicals from the 143 chemicals in the dataset. The sensitivity and overall accuracy for the 143 chemicals were 83% and 80%, respectively. In contrast, sensitivity and overall accuracy for the 112 chemicals with log Kow values below 3.5 improved to 94% and 88%, respectively. These data suggested that the h-CLAT could successfully detect sensitizers with log Kow values up to 3.5. When chemicals with log Kow values greater than 3.5 that were deemed positive by h-CLAT were included with the 112 chemicals, the sensitivity and accuracy in terms of the resulting applicable 128 chemicals out of the 143 chemicals became 95% and 88%, respectively. The use of log Kow values gave the h-CLAT a higher predictive performance. Our results demonstrated that the h-CLAT could predict sensitizing potential of various chemicals, which contain lipophilic chemicals using a large-scale chemical dataset.

  11. Coefficient Alpha: A Reliability Coefficient for the 21st Century?

    Science.gov (United States)

    Yang, Yanyun; Green, Samuel B.

    2011-01-01

    Coefficient alpha is almost universally applied to assess reliability of scales in psychology. We argue that researchers should consider alternatives to coefficient alpha. Our preference is for structural equation modeling (SEM) estimates of reliability because they are informative and allow for an empirical evaluation of the assumptions…

  12. Coefficient estimates of negative powers and inverse coefficients for ...

    Indian Academy of Sciences (India)

    and the inequality is sharp for the inverse of the Koebe function k(z) = z/(1 − z)2. An alternative approach to the inverse coefficient problem for functions in the class S has been investigated by Schaeffer and Spencer [27] and FitzGerald [6]. Although, the inverse coefficient problem for the class S has been completely solved ...

  13. Measuring of heat transfer coefficient

    DEFF Research Database (Denmark)

    Henningsen, Poul; Lindegren, Maria

    Subtask 3.4 Measuring of heat transfer coefficient Subtask 3.4.1 Design and setting up of tests to measure heat transfer coefficient Objective: Complementary testing methods together with the relevant experimental equipment are to be designed by the two partners involved in order to measure...... the heat transfer coefficient for a wide range of interface conditions in hot and warm forging processes. Subtask 3.4.2 Measurement of heat transfer coefficient The objective of subtask 3.4.2 is to determine heat transfer values for different interface conditions reflecting those typically operating in hot...

  14. Polaron in the dilute critical Bose condensate

    Science.gov (United States)

    Pastukhov, Volodymyr

    2018-05-01

    The properties of an impurity immersed in a dilute D-dimensional Bose gas at temperatures close to its second-order phase transition point are considered. Particularly by means of the 1/N-expansion, we calculate the leading-order polaron energy and the damping rate in the limit of vanishing boson–boson interaction. It is shown that the perturbative effective mass and the quasiparticle residue diverge logarithmically in the long-length limit, signalling the non-analytic behavior of the impurity spectrum and pole-free structure of the polaron Green’s function in the infrared region, respectively.

  15. Confluence Model or Resource Dilution Hypothesis?

    DEFF Research Database (Denmark)

    Jæger, Mads

    have a negative effect on educational attainment most studies cannot distinguish empirically between the CM and the RDH. In this paper, I use the different theoretical predictions in the CM and the RDH on the role of cognitive ability as a partial or complete mediator of the sibship size effect......Studies on family background often explain the negative effect of sibship size on educational attainment by one of two theories: the Confluence Model (CM) or the Resource Dilution Hypothesis (RDH). However, as both theories – for substantively different reasons – predict that sibship size should...

  16. The Evolution of Pearson's Correlation Coefficient

    Science.gov (United States)

    Kader, Gary D.; Franklin, Christine A.

    2008-01-01

    This article describes an activity for developing the notion of association between two quantitative variables. By exploring a collection of scatter plots, the authors propose a nonstandard "intuitive" measure of association; and by examining properties of this measure, they develop the more standard measure, Pearson's Correlation Coefficient. The…

  17. Study of CO 2 stability and electrochemical oxygen activation of mixed conductors with low thermal expansion coefficient based on the TbBaCo 3ZnO 7+ δ system

    Science.gov (United States)

    Vert, Vicente B.; Serra, José M.

    The influence of different application-oriented factors on the electrochemical activity and stability of TbBaCo 3ZnO 7+ δ when used as a solid oxide fuel cell cathode has been studied. Calcination at temperatures above 900 °C (e.g. 1000 °C) leads to a significant increase in the electrode polarization resistance. The effect of the sintering temperature of the TbBaCo 3ZnO 7+ δ cathode seems to be more important than the effect produced by the Tb substitution as observed when compared with 900 °C-sintered YBaCo 3ZnO 7+ δ; and ErBaCo 3ZnO 7+ δ electrode performances. The presence of CO 2 in the air flow leads to an increase of roughly 10% in the polarization resistance for the whole studied temperature range (500-850 °C) while this effect is reversible. Analysis of the impedance spectroscopy measurements shows that the exchange rate constant (k G from Gerischer element) is significantly affected by CO 2 at temperatures below 700 °C, while the diffusion coefficient related parameter is slightly influenced at low temperatures. Electrode degrades with a low constant rate of 1 mΩ cm 2 h -1 after 60 h. This cathode material exhibits high CO 2 tolerance, as shown by temperature programmed treatment under a continuous gas flow of air with 5% CO 2, and a relatively low thermal expansion coefficient.

  18. New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2011-09-01

    Full Text Available We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl, Br, NO3, HSO4, and SO42−. Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization

  19. Influence of dilution of butenes with isobutane on the course of alkylation on a zeolite catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Bortyshevskii, V.A.; Bezuglaya, A.K.; Galich, P.N.; Patrilyak, V.I.; Vaiburskii, V.L.

    1985-09-01

    The authors designed an assembly, shown schematically, in which the component ratios could be varied over a wide range, by internal circulation of isobutane. The reactor, operating isothermally, was made of glass tubing and was attached to the boiler with external heathers and the dephlegmator. It was determined that the course of alkylation of isobutane with butenes depends significantly on the reaction conditions, and primarilly on the ratio of isobutane to butenes in the reaction zone. Alkylation experiments of high dilutions of butenes revealed a series of consecutive processes, which can't be identified at low dilution because of their superposition. The influence of dilution is manifested mainly through the character and subsequent transformation of the active complexes formed on the catalyst surface. Therefore conditions in which formation and subsequent transformation of the active complexes proceed gradually should be regarded as favorable for alkylation.

  20. Neutron scattering study of dilute supercritical solutions

    International Nuclear Information System (INIS)

    Cochran, H.D.; Wignall, G.D.; Shah, V.M.; Londono, J.D.; Bienkowski, P.R.

    1994-01-01

    Dilute solutions in supercritical solvents exhibit interesting microstructures that are related to their dramatic macroscopic behavior. In typical attractive solutions, solutes are believed to be surrounded by clusters of solvent molecules, and solute molecules are believed to congregate in the vicinity of one another. Repulsive solutions, on the other hand, exhibit a local region of reduced solvent density around the solute with solute-solute congregation. Such microstructures influence solubility, partial molar volume, reaction kinetics, and many other properties. We have undertaken to observe these interesting microstructures directly by neutron scattering experiments on dilute noble gas systems including Ar. The three partial structure factors for such systems and the corresponding pair correlation functions can be determined by using the isotope substitution technique. The systems studied are uniquely suited for our objectives because of the large coherent neutron scattering length of the isotope 36 Ar and because of the accurate potential energy functions that are available for use in molecular simulations and theoretical calculations to be compared with the scattering results. We will describe our experiment, the unique apparatus we have built for it, and the neutron scattering results from our initial allocations of beam time. We will also describe planned scattering experiments to follow those with noble gases, including study of long-chain molecules in supercritical solvents. Such studies will involve hydrocarbon mixtures with and without deuteration to provide contrast

  1. Universal water-dilutable inhibited protective lubricants

    International Nuclear Information System (INIS)

    Mamtseva, M.V.; Kardash, N.V.; Latynina, M.B.

    1993-01-01

    In the interest of environmental protection, improvement of working conditions, and reduced fire hazard in production operations, water-based protective lubricants are now available in a wide assortment, and the production volume has increased greatly. The term water-dilutable inhibited protective lubricants (WDIPL) means water-soluble, water-emulsifiable, or water-dispersible products with the dual function of reducing friction and wear and protecting metal surfaces against corrosion for specified periods of time. According to the standard Unified System of Protection Against Corrosion and Aging (COST 9.103-78), WDIPLs are classed as products for the temporary corrosion protection of metals and end-items. In the general class of WDIPLs one can identify water-dilutable combination corrosion inhibitors, film-forming inhibited petroleum compositions (FIPC-d), detergent-preservative fluids, operational-preservative lubricating-cooling process compounds (ICPC), and, finally, universal multifunctional products. Combined corrosion inhibitors may consist of water-soluble organic and inorganic compounds; water/oil and oil-soluble surfactants - corrosion inhibitors of the chemisorption type or donor and/or acceptor types; shielding inhibitors of the adsorption type; and fast-acting water-displacing components. 23 refs

  2. Capsize of polarization in dilute photonic crystals.

    Science.gov (United States)

    Gevorkian, Zhyrair; Hakhoumian, Arsen; Gasparian, Vladimir; Cuevas, Emilio

    2017-11-29

    We investigate, experimentally and theoretically, polarization rotation effects in dilute photonic crystals with transverse permittivity inhomogeneity perpendicular to the traveling direction of waves. A capsize, namely a drastic change of polarization to the perpendicular direction is observed in a one-dimensional photonic crystal in the frequency range 10 ÷ 140 GHz. To gain more insights into the rotational mechanism, we have developed a theoretical model of dilute photonic crystal, based on Maxwell's equations with a spatially dependent two dimensional inhomogeneous dielectric permittivity. We show that the polarization's rotation can be explained by an optical splitting parameter appearing naturally in Maxwell's equations for magnetic or electric fields components. This parameter is an optical analogous of Rashba like spin-orbit interaction parameter present in quantum waves, introduces a correction to the band structure of the two-dimensional Bloch states, creates the dynamical phase shift between the waves propagating in the orthogonal directions and finally leads to capsizing of the initial polarization. Excellent agreement between theory and experiment is found.

  3. Static and dynamic light scattering studies on dilute polyrotaxane solutions

    Science.gov (United States)

    Kume, Tetsuya; Araki, Jun; Sakai, Yasuhiro; Mayumi, Koichi; Kidowaki, Masatoshi; Yokoyama, Hideaki; Ito, Kohzo

    2009-08-01

    Static and dynamic light scattering measurements were performed for dilute polyrotaxane solutions in different types of solvent systems, i.e. dimethylacetamide (DMAc) or dimethylformamide (DMF) containing 1-6 wt% lithium chloride (LiCl), 1 M aqueous sodium hydroxide (NaOH) and dimethylsulfoxide (DMSO). No aggregation of the polyrotaxane in DMF/LiCl was confirmed in the present study. Radius of gyration of the dissolved polyrotaxane was largest in NaOHaq., followed by values in amide solvents/LiCl and that in DMSO, and was probably dominated not by Coulombic repulsion but by the mutual affinity between solvent and polyrotaxane. Ratio of radius of gyration to hydrodynamic radius suggested the flexible random-coiled conformation in DMSO and relatively more extended, semi-flexible ones in amide solvents/LiCl and NaOHaq. The obtained values of second virial coefficient and weight average molecular weight seemed to be affected by a potential change in differential refractive index increments, caused by selective macrocationization or ionization.

  4. Static and dynamic light scattering studies on dilute polyrotaxane solutions

    International Nuclear Information System (INIS)

    Kume, Tetsuya; Sakai, Yasuhiro; Mayumi, Koichi; Kidowaki, Masatoshi; Yokoyama, Hideaki; Ito, Kohzo; Araki, Jun

    2009-01-01

    Static and dynamic light scattering measurements were performed for dilute polyrotaxane solutions in different types of solvent systems, i.e. dimethylacetamide (DMAc) or dimethylformamide (DMF) containing 1-6 wt% lithium chloride (LiCl), 1 M aqueous sodium hydroxide (NaOH) and dimethylsulfoxide (DMSO). No aggregation of the polyrotaxane in DMF/LiCl was confirmed in the present study. Radius of gyration of the dissolved polyrotaxane was largest in NaOHaq., followed by values in amide solvents/LiCl and that in DMSO, and was probably dominated not by Coulombic repulsion but by the mutual affinity between solvent and polyrotaxane. Ratio of radius of gyration to hydrodynamic radius suggested the flexible random-coiled conformation in DMSO and relatively more extended, semi-flexible ones in amide solvents/LiCl and NaOHaq. The obtained values of second virial coefficient and weight average molecular weight seemed to be affected by a potential change in differential refractive index increments, caused by selective macrocationization or ionization.

  5. Assessments of conversion coefficients between equivalent dose and accumulated activity using pre-dose scanning images of patients subjected to radioiodine treatment and the Fax/Egs4 computational model

    International Nuclear Information System (INIS)

    Lopes Filho, Ferdinand de J.; Vieira, Jose W.; Andrade Lima, Fernando R. de

    2008-01-01

    The radioiodine is a technique for treatment of thyroid cancer. In this technique, the patients are submitted to the incorporation of the radioactive substance sodium iodide (Na 131 I), which reacts with physiologically metastasis, thyroid tissue remains of and other organs and tissues of the human body. The locations of these reactions are known as areas of highest concentration, hipercaptured areas, hiperconcentrator areas, 'hot areas' or organ-sources and are viewed through images of nuclear medicine scan known as pre-dose (front and rear). To obtain these images, the patient receives, orally, a quantity of 131 I with low activity (± 74 MBq) and is positioned in the chamber of flicker. According to the attendance of hot areas shown in the images, the doctor determines the nuclear activity to be administered in treatment. This analysis is purely qualitative. In this study, the scanning images of pre-dose were adjusted to the dimensions of FAX voxel phantom, and the hot areas correspond to internal sources of the proposed model. Algorithms were developed to generate particles (photons and electrons) in these regions of the FAX. To estimate the coefficients of conversions between equivalent dose and accumulated activity in major radiosensitive organs, FAX and algorithms source were coupled to the Monte Carlo EGS4 code (Electron Gamma Shower, version 4). With these factors is possible to estimate the equivalent doses in the radiosensitive organs and tissues of patients as long as is know the activity administered and the half-life of organic sources. (author)

  6. Clinical performance of a new hepatitis B surface antigen quantitative assay with automatic dilution

    Directory of Open Access Journals (Sweden)

    Ta-Wei Liu

    2015-01-01

    Full Text Available Hepatitis B virus surface antigen (HBsAg levels reflect disease status and can predict the clinical response to antiviral treatment; however, the emergence of HBsAg mutant strains has become a challenge. The Abbott HBsAg quantification assay provides enhanced detection of HBsAg and HBsAg mutants. We aimed to evaluate the performance of the Abbott HBsAg quantification assay with automatic sample dilutions (shortened as automatic Architect assay, compared with the Abbott HBsAg quantification assay with manual sample dilutions (shortened as manual Architect assay and the Roche HBsAg quantification assay with automatic sample dilutions (shortened as Elecsys. A total of 130 sera samples obtained from 87 hepatitis B virus (HBV-infected patients were collected to assess the correlation between the automatic and manual Architect assays. Among the 87 patients, 41 provided 42 sera samples to confirm the linearity and reproducibility of the automatic Architect assay, and find out the correlation among the Elecsys and two Architect assays. The coefficients of variation (0.44–9.53% and R2 = 0.996–1, which were both determined using values obtained from the automatic Architect assay, showed good reproducibility and linearity. Results of the two Architect assays demonstrated a feasible correlation (n = 130 samples; R = 0.898, p  0.93 in all cases. In conclusion, the correlation between the automatic and manual dilution Architect assays was feasible, particularly in the HBeAg-negative and low DNA groups. With lower labor costs and less human error than the manual version, the Abbott automatic dilution Architect assay provided a good clinical performance with regard to the HBsAg levels.

  7. Formulas for activity coefficients of individual ions

    NARCIS (Netherlands)

    Ritsema, C.J.; Bloemer, F.

    1986-01-01

    For chemical calculations with gaseous equilibria and for non-ionic reactions in solution one can calculate in terms of concentrations to a fairly good approximation. However, in dealing with ionic reactions, with certain aspects of kinetics in solution, and with elcetromotive force studies,

  8. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2014-01-01

    into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods...

  9. Probabilistic optimization of safety coefficients

    International Nuclear Information System (INIS)

    Marques, M.; Devictor, N.; Magistris, F. de

    1999-01-01

    This article describes a reliability-based method for the optimization of safety coefficients defined and used in design codes. The purpose of the optimization is to determine the partial safety coefficients which minimize an objective function for sets of components and loading situations covered by a design rule. This objective function is a sum of distances between the reliability of the components designed using the safety coefficients and a target reliability. The advantage of this method is shown on the examples of the reactor vessel, a vapour pipe and the safety injection circuit. (authors)

  10. Alpha-clustering in dilute nucleonic sea

    International Nuclear Information System (INIS)

    Tohsaki, Akihiro

    1999-01-01

    α-clusters are expected to come out here and there in nucleonic sea owing to energetic benefit as its density is diluted. We propose a precise treatment to elucidate α-clusterized process in nucleonic sea after the breakdown of the uniformness. In order to do this, an infinite number of nucleons are considered by taking account of both the Pauli exclusion principle and effective internucleon forces. This method is called a microscopic approach, which has been successful in an α-cluster structure in light nuclei. In particular, we shed light on overcoming difficulties in a static model within the microscopic framework. This improvement is verified by using the empirical value in Weizaecker's mass formula. (author)

  11. Water Metabolism of Walruses by Isotope Dilution

    DEFF Research Database (Denmark)

    Acquarone, M.; Born, E. W.; Chwalibog, A.

    was sampled via an epidural catheter, at regular intervals, for up to seven hours after the initial enrichment to assess isotope equilibration in the body water pools. Five individuals returned to the haul-out after feeding trips of varying duration (158±86 hr, 44-287 hr) where they were immobilized again......In August 2000, the hydrogen isotope dilution method was used on 7 adult male Atlantic walruses (Odobenus rosmarus rosmarus) (weight: 1197±148 kg, mean±SD, range 1013-1508 kg) at a terrestrial haul-out in Northeastern Greenland to determine their body water pool sizes and body water turnover rates....... During immobilization by use of etorphine HCl (reversed with diprenorphine HCl), a first blood sample was taken to measure background isotope levels. The animals were then enriched with deuterium oxide by infusion into the epidural vein. During recovery, while the animals were still on the beach, blood...

  12. Tunnel backfill erosion by dilute water

    Energy Technology Data Exchange (ETDEWEB)

    Olin, M. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2014-03-15

    The goal was to estimate smectite release from tunnel backfill due to dilute groundwater pulse during post glacial conditions. The plan was to apply VTT's two different implementations (BESW{sub D} and BESW{sub S}) of well-known model of Neretnieks et al. (2009). It appeared difficult to produce repeatable results using this model in COMSOL 4.2 environment, therefore a semi-analytical approximate approach was applied, which enabled to take into account both different geometry and smectite content in tunnel backfill as compared to buffer case. The results are quite similar to buffer results due to the decreasing effect of smaller smectite content and the increasing effect of larger radius. (orig.)

  13. Ultrafast magnetization dynamics in diluted magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Morandi, O [INRIA Nancy Grand-Est and Institut de Recherche en Mathematiques Avancees, 7 rue Rene Descartes, F-67084 Strasbourg (France); Hervieux, P-A; Manfredi, G [Institut de Physique et Chimie des Materiaux de Strasbourg, 23 rue du Loess, F-67037 Strasbourg (France)], E-mail: morandi@dipmat.univpm.it

    2009-07-15

    We present a dynamical model that successfully explains the observed time evolution of the magnetization in diluted magnetic semiconductor quantum wells after weak laser excitation. Based on the pseudo-fermion formalism and a second-order many-particle expansion of the exact p-d exchange interaction, our approach goes beyond the usual mean-field approximation. It includes both the sub-picosecond demagnetization dynamics and the slower relaxation processes that restore the initial ferromagnetic order in a nanosecond timescale. In agreement with experimental results, our numerical simulations show that, depending on the value of the initial lattice temperature, a subsequent enhancement of the total magnetization may be observed within the timescale of a few hundred picoseconds.

  14. Mechanisms of urine concentration and dilution (1961)

    International Nuclear Information System (INIS)

    Morel, F.; Guinnebault, M.

    1961-01-01

    This paper is devoted to the analysis of a problem in the field of renal physiology which has shown many new developments during the course of the last few years. The following are treated successively: a) the data obtained from measurements of free water clearance and their interpretation; b) the data provided by nephron morphology and the comparative anatomy of the kidney ; c) the data relative to the existence of an intrarenal osmotic gradient; d) the principle of concentration multiplication by a counter current technique; e) the present day theory of counter current concentration of urine, and f) the physiological check on dilution and concentration mechanisms in urine. Lastly, the advantages of the modern theory and the unknown factors which remain are discussed. (authors) [fr

  15. Tunnel backfill erosion by dilute water

    International Nuclear Information System (INIS)

    Olin, M.

    2014-03-01

    The goal was to estimate smectite release from tunnel backfill due to dilute groundwater pulse during post glacial conditions. The plan was to apply VTT's two different implementations (BESW D and BESW S ) of well-known model of Neretnieks et al. (2009). It appeared difficult to produce repeatable results using this model in COMSOL 4.2 environment, therefore a semi-analytical approximate approach was applied, which enabled to take into account both different geometry and smectite content in tunnel backfill as compared to buffer case. The results are quite similar to buffer results due to the decreasing effect of smaller smectite content and the increasing effect of larger radius. (orig.)

  16. Critical exponents for diluted resistor networks.

    Science.gov (United States)

    Stenull, O; Janssen, H K; Oerding, K

    1999-05-01

    An approach by Stephen [Phys. Rev. B 17, 4444 (1978)] is used to investigate the critical properties of randomly diluted resistor networks near the percolation threshold by means of renormalized field theory. We reformulate an existing field theory by Harris and Lubensky [Phys. Rev. B 35, 6964 (1987)]. By a decomposition of the principal Feynman diagrams, we obtain diagrams which again can be interpreted as resistor networks. This interpretation provides for an alternative way of evaluating the Feynman diagrams for random resistor networks. We calculate the resistance crossover exponent phi up to second order in epsilon=6-d, where d is the spatial dimension. Our result phi=1+epsilon/42+4epsilon(2)/3087 verifies a previous calculation by Lubensky and Wang, which itself was based on the Potts-model formulation of the random resistor network.

  17. A horizontal dilution refrigerator for polarized target

    International Nuclear Information System (INIS)

    Isagawa, S.; Ishimoto, S.; Masaike, A.; Morimoto, K.

    1978-01-01

    A horizontal dilution refrigerator was constructed with a view to the spin frozen target and the deuteron polarized target. High cooling power at high temperature such as 3.7 mW at 400 mK serves for overcoming a heat load of microwave to polarize the nuclear spins in the target material. The cooling power at 50 mK was 50 μW, which is sufficient to hold the high nuclear polarization for long time. The lowest temperature reached was 26 mK. The refrigerator has rather simple heat exchangers, a long stainless steel double tube heat exchanger and two coaxial type heat exchangers with sintered copper. The mixing chamber is made of polytetrafluoroethylene (TFE) and demountable so that the target material can be easily put into it. (Auth.)

  18. Cost effectiveness of dilute chemical decontamination

    International Nuclear Information System (INIS)

    Le Surf, J.E.; Weyman, G.D.

    1983-01-01

    The origin and basic principles of the dilute chemical decontamination (DCD) concept are described and illustrated by reference to the CAN-DECON process. The estimated dose savings from the actual application of the process at several reactors are presented and discussed. Two methods of performing a cost/benefit appraisal are described and discussed. This methodology requires more study by the nuclear industry, including collection by station staff of relevant data on which future cost/benefit appraisals may be based. Finally, three illustrative cases are examinated to show the breakeven point and potential savings achievable by DCD with different initial radiation fields and different amounts of work to be done. The overall conclusion is that there are many situations in which DCD is desirable to reduce radiation exposure of workers, to save costs to the station, and to ease the performance of maintenance and repair work on reactor systems

  19. Guideline on Isotope Dilution Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Amy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-05-19

    Isotope dilution mass spectrometry is used to determine the concentration of an element of interest in a bulk sample. It is a destructive analysis technique that is applicable to a wide range of analytes and bulk sample types. With this method, a known amount of a rare isotope, or ‘spike’, of the element of interest is added to a known amount of sample. The element of interest is chemically purified from the bulk sample, the isotope ratio of the spiked sample is measured by mass spectrometry, and the concentration of the element of interest is calculated from this result. This method is widely used, although a mass spectrometer required for this analysis may be fairly expensive.

  20. Calculations for BDAS Setpoint with Non-conservative Boron Dilution Analysis

    International Nuclear Information System (INIS)

    Lee, Hwan Soo; Shin, Ho Cheol; Kim, Yong Bae

    2014-01-01

    BDAS (Boron Dilution Alarm System) utilizes the ex-core detector instrumentation signals to detect a possible inadvertent boron dilution event during operation mode 3, 4, 5, 6. For boron dilution analysis, discrepancies in the active coolant volume and the assumed linearity of the ex-core instrumentation response were identified for CE type PWR and they were reported by NASL-04-02 These discrepancies have potential to impact to determine BDAS setpoint in a non-conservative manner Therefore, in this study, the calculation of BDAS setpoint with those discrepancies condition about OPR1000 was performed and analyzed for checking the safety of BDAS. The new BDAS setpoint is calculated with conservative condition which recommended from Westinghouse Electric Company. The setpoint of BDAS using non-linear ICRR curve decrease to about 5% compared to the setpoint of that using linear ICRR curve. And this effect of the non-linearity is to slightly delay the boron dilution alarm during the inadvertence boron dilution at mode 3, 4, and 5

  1. Velocity distributions in dilute granular systems

    NARCIS (Netherlands)

    van Zon, J.S.; Mac Kintosh, F.C.

    2005-01-01

    We investigate the idea that velocity distributions in granular gases are determined mainly by η, the coefficient of restitution and q, which measures the relative importance of heating (or energy input) to collisions. To this end, we study by numerical simulation the properties of inelastic gases

  2. Effective Microporosity for Enhanced Adsorption Capacity of Cr (VI) from Dilute Aqueous Solution: Isotherm and Kinetics

    OpenAIRE

    Lloyd Mukosha; Maurice S. Onyango; Aoyi Ochieng; John Siame

    2017-01-01

    The adsorbent pore structure significant to enhanced adsorption capacity of Cr (VI) from dilute aqueous solution is evaluated. As reference, low-cost micro-mesoporous activated carbon (AC) of high basicity, mesoporosity centred about 2.4 nm, and effective microporosity centred about 0.9 nm was tested for removal of Cr (VI) from dilute aqueous solution in batch mode. At pH 2 the low-cost AC exhibited highly improved Langmuir Cr (VI) capacity of 115 mg/g which was competitive to high performanc...

  3. Basic research in homeopathy and ultra-high dilutions: what progress is being made?

    Science.gov (United States)

    Betti, Lucietta; Trebbi, Grazia; Olioso, Debora; Marzotto, Marta; Bellavite, Paolo

    2013-04-01

    This report summarises the latest research developments in the field of high dilutions and homeopathy, as presented at the GIRI symposium of the leading international organisation of scientists in this field, in Florence, Italy in September 2012. The scientific community's early scepticism concerning the possible biological and pharmacological activity of highly diluted solutions, is giving way to a more open-minded attitude that no longer obstructs critical and experimental investigations in this emerging field of biomedicine. Copyright © 2013. Published by Elsevier Ltd.. All rights reserved.

  4. High-throughput ab-initio dilute solute diffusion database.

    Science.gov (United States)

    Wu, Henry; Mayeshiba, Tam; Morgan, Dane

    2016-07-19

    We demonstrate automated generation of diffusion databases from high-throughput density functional theory (DFT) calculations. A total of more than 230 dilute solute diffusion systems in Mg, Al, Cu, Ni, Pd, and Pt host lattices have been determined using multi-frequency diffusion models. We apply a correction method for solute diffusion in alloys using experimental and simulated values of host self-diffusivity. We find good agreement with experimental solute diffusion data, obtaining a weighted activation barrier RMS error of 0.176 eV when excluding magnetic solutes in non-magnetic alloys. The compiled database is the largest collection of consistently calculated ab-initio solute diffusion data in the world.

  5. Dielectric relaxation studies of dilute solutions of amides

    Energy Technology Data Exchange (ETDEWEB)

    Malathi, M.; Sabesan, R.; Krishnan, S

    2003-11-15

    The dielectric constants and dielectric losses of formamide, acetamide, N-methyl acetamide, acetanilide and N,N-dimethyl acetamide in dilute solutions of 1,4-dioxan/benzene have been measured at 308 K using 9.37 GHz, dielectric relaxation set up. The relaxation time for the over all rotation {tau}{sub (1)} and that for the group rotation {tau}{sub (2)} of (the molecules were determined using Higasi's method. The activation energies for the processes of dielectric relaxation and viscous flow were determined by using Eyring's rate theory. From relaxation time behaviour of amides in non-polar solvent, solute-solvent and solute-solute type of molecular association is proposed.

  6. Heat Transfer in Boiling Dilute Emulsion with Strong Buoyancy

    Science.gov (United States)

    Freeburg, Eric Thomas

    Little attention has been given to the boiling of emulsions compared to that of boiling in pure liquids. The advantages of using emulsions as a heat transfer agent were first discovered in the 1970s and several interesting features have since been studied by few researchers. Early research focuses primarily on pool and flow boiling and looks to determine a mechanism by which the boiling process occurs. This thesis looks at the boiling of dilute emulsions in fluids with strong buoyant forces. The boiling of dilute emulsions presents many favorable characteristics that make it an ideal agent for heat transfer. High heat flux electronics, such as those seen in avionics equipment, produce high heat fluxes of 100 W/cm2 or more, but must be maintained at low temperatures. So far, research on single phase convection and flow boiling in small diameter channels have yet to provide an adequate solution. Emulsions allow the engineer to tailor the solution to the specific problem. The fluid can be customized to retain the high thermal conductivity and specific heat capacity of the continuous phase while enhancing the heat transfer coefficient through boiling of the dispersed phase component. Heat transfer experiments were carried out with FC-72 in water emulsions. FC-72 has a saturation temperature of 56 °C, far below that of water. The parameters were varied as follows: 0% ≤ epsilon ≤ 1% and 1.82 x 1012 ≤ RaH ≤ 4.42 x 1012. Surface temperatures along the heated surface reached temperature that were 20 °C in excess of the dispersed phase saturation temperature. An increase of ˜20% was seen in the average Nusselt numbers at the highest Rayleigh numbers. Holography was used to obtain images of individual and multiple FC-72 droplets in the boundary layer next to the heated surface. The droplet diameters ranged from 0.5 mm to 1.3 mm. The Magnus effect was observed when larger individual droplets were injected into the boundary layer, causing the droplets to be pushed

  7. Isotope dilution mass spectrometry for nuclear material accountability measurements: dreams and reality

    International Nuclear Information System (INIS)

    Deron, S.; )

    1996-01-01

    Gravimetry, titration, coulometry and isotope dilution mass spectrometry are alternative techniques which can be used to obtain elemental assays of the desirable accuracy. The communication briefly describes the characteristics of the procedure and summarizes a wealth of experience accumulated during actual accountability verification activities

  8. EDITORIAL: Focus on Dilute Magnetic Semiconductors FOCUS ON DILUTE MAGNETIC SEMICONDUCTORS

    Science.gov (United States)

    Chambers, Scott A.; Gallagher, Bryan

    2008-05-01

    This focus issue of New Journal of Physics is devoted to the materials science of dilute magnetic semiconductors (DMS). A DMS is traditionally defined as a diamagnetic semiconductor doped with a few to several atomic per cent of some transition metal with unpaired d electrons. Several kinds of dopant-dopant interactions can in principle couple the dopant spins leading to a ferromagnetic ground state in a dilute magnetic system. These include superexchange, which occurs principally in oxides and only between dopants with one intervening oxygen, and double exchange, in which dopants of different formal charges exchange an electron. In both of these mechanisms, the ferromagnetic alignment is not critically dependent on free carriers in the host semiconductor because exchange occurs via bonds. A third mechanism, discovered in the last few years, involves electrons associated with lattice defects that can apparently couple dopant spins. This mechanism is not well understood. Finally, the most desirable mechanism is carrier-mediated exchange interaction in which the dopant spins are coupled by itinerant electrons or holes in the host semiconductor. This mechanism introduces a fundamental link between magnetic and electrical transport properties and offers the possibility of new spintronic functionalities. In particular electrical gate control of ferromagnetism and the use of spin polarized currents to carry signals for analog and digital applications. The spin light emitting diode is a prototypical device of this kind that has been extensively used to characterize the extent of spin polarization in the active light emitting semiconductor heterostructure. The prototypical carrier mediated ferromagnetic DMS is Mn-doped GaAs. This and closely related narrow gap III-V materials have been very extensively studied. Their properties are generally quite well understood and they have led to important insights into fundamental properties of ferromagnetic systems with strong spin

  9. Quadrature formulas for Fourier coefficients

    KAUST Repository

    Bojanov, Borislav; Petrova, Guergana

    2009-01-01

    We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node

  10. Diffusion coefficient for anomalous transport

    International Nuclear Information System (INIS)

    1986-01-01

    A report on the progress towards the goal of estimating the diffusion coefficient for anomalous transport is given. The gyrokinetic theory is used to identify different time and length scale inherent to the characteristics of plasmas which exhibit anomalous transport

  11. Asymptotic Distribution of Eigenvalues of Weakly Dilute Wishart Matrices

    Energy Technology Data Exchange (ETDEWEB)

    Khorunzhy, A. [Institute for Low Temperature Physics (Ukraine)], E-mail: khorunjy@ilt.kharkov.ua; Rodgers, G. J. [Brunel University, Uxbridge, Department of Mathematics and Statistics (United Kingdom)], E-mail: g.j.rodgers@brunel.ac.uk

    2000-03-15

    We study the eigenvalue distribution of large random matrices that are randomly diluted. We consider two random matrix ensembles that in the pure (nondilute) case have a limiting eigenvalue distribution with a singular component at the origin. These include the Wishart random matrix ensemble and Gaussian random matrices with correlated entries. Our results show that the singularity in the eigenvalue distribution is rather unstable under dilution and that even weak dilution destroys it.

  12. Turbid Media Extinction Coefficient for Near-Infrared Laser Radiation

    International Nuclear Information System (INIS)

    Dreischuh, T; Gurdev, L; Vankov, O; Stoyanov, D; Avramov, L

    2015-01-01

    In this work, extended investigations are performed of the extinction coefficient of Intralipid-20% dilutions in distilled water depending on the Intralipid concentration, for laser radiation wavelengths in the red and near-infrared regions covering the so-called tissue optical window. The extinction is measured by using an approach we have developed recently based on the features of the spatial intensity distribution of laser-radiation beams propagating through semi-infinite turbid media. The measurements are conducted using separately two dilution- containing plexiglass boxes of different sizes and volumes, in order to prove the appropriateness of the assumption of semi-infinite turbid medium. The experimental results for the extinction are in agreement with our previous results and with empiric formulae found by other authors concerning the wavelength dependence of the scattering coefficient of Intralipid – 10% and Intralipid – 20%. They are also in agreement with known data of the water absorptance. It is estimated as well that the wavelengths around 1320 nm would be advantageous for deep harmless sensing and diagnostics of tissues

  13. Reverse osmosis performance of cellulose acetate membranes in the separation of uranium from dilute solutions

    International Nuclear Information System (INIS)

    Sastri, V.S.; Ashbrook, A.W.

    1976-01-01

    Batch 316-type cellulose acetate membranes were characterized in terms of pure water permeability constant, solute transport parameter, and mass transfer coefficient with a reference system of aqueous sodium chloride solution. These membranes were used in the determination of reverse osmosis characteristics such as product rate and solute separation in the case of uranium sulfate solutions of different concentrations (100 to 8000 ppM) in the feed solutions. A long-term test extending over a week has been carried out with dilute uranium solutions. Reverse osmosis treatment of synthetic mine water sample showed satisfactory performance of the membranes in the separation of metal ions

  14. Cold dilute neutron matter on the lattice. II. Results in the unitary limit

    International Nuclear Information System (INIS)

    Lee, Dean; Schaefer, Thomas

    2006-01-01

    This is the second of two articles that investigate cold dilute neutron matter on the lattice using pionless effective field theory. In the unitary limit, where the effective range is zero and scattering length is infinite, simple scaling relations relate thermodynamic functions at different temperatures. When the second virial coefficient is properly tuned, we find that the lattice results obey these scaling relations. We compute the energy per particle, pressure, spin susceptibility, dineutron correlation function, and an upper bound for the superfluid critical temperature

  15. Fuel Temperature Coefficient of Reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Loewe, W.E.

    2001-07-31

    A method for measuring the fuel temperature coefficient of reactivity in a heterogeneous nuclear reactor is presented. The method, which is used during normal operation, requires that calibrated control rods be oscillated in a special way at a high reactor power level. The value of the fuel temperature coefficient of reactivity is found from the measured flux responses to these oscillations. Application of the method in a Savannah River reactor charged with natural uranium is discussed.

  16. Properties of Traffic Risk Coefficient

    Science.gov (United States)

    Tang, Tie-Qiao; Huang, Hai-Jun; Shang, Hua-Yan; Xue, Yu

    2009-10-01

    We use the model with the consideration of the traffic interruption probability (Physica A 387(2008)6845) to study the relationship between the traffic risk coefficient and the traffic interruption probability. The analytical and numerical results show that the traffic interruption probability will reduce the traffic risk coefficient and that the reduction is related to the density, which shows that this model can improve traffic security.

  17. 21 CFR 866.2500 - Microtiter diluting and dispensing device.

    Science.gov (United States)

    2010-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2500... a mechanical device intended for medical purposes to dispense or serially dilute very small...

  18. Dilute acid/metal salt hydrolysis of lignocellulosics

    Science.gov (United States)

    Nguyen, Quang A.; Tucker, Melvin P.

    2002-01-01

    A modified dilute acid method of hydrolyzing the cellulose and hemicellulose in lignocellulosic material under conditions to obtain higher overall fermentable sugar yields than is obtainable using dilute acid alone, comprising: impregnating a lignocellulosic feedstock with a mixture of an amount of aqueous solution of a dilute acid catalyst and a metal salt catalyst sufficient to provide higher overall fermentable sugar yields than is obtainable when hydrolyzing with dilute acid alone; loading the impregnated lignocellulosic feedstock into a reactor and heating for a sufficient period of time to hydrolyze substantially all of the hemicellulose and greater than 45% of the cellulose to water soluble sugars; and recovering the water soluble sugars.

  19. Cross-validated stable-isotope dilution GC-MS and LC-MS/MS assays for monoacylglycerol lipase (MAGL) activity by measuring arachidonic acid released from the endocannabinoid 2-arachidonoyl glycerol.

    Science.gov (United States)

    Kayacelebi, Arslan Arinc; Schauerte, Celina; Kling, Katharina; Herbers, Jan; Beckmann, Bibiana; Engeli, Stefan; Jordan, Jens; Zoerner, Alexander A; Tsikas, Dimitrios

    2017-03-15

    2-Arachidonoyl glycerol (2AG) is an endocannabinoid that activates cannabinoid (CB) receptors CB1 and CB2. Monoacylglycerol lipase (MAGL) inactivates 2AG through hydrolysis to arachidonic acid (AA) and glycerol, thus modulating the activity at CB receptors. In the brain, AA released from 2AG by the action of MAGL serves as a substrate for cyclooxygenases which produce pro-inflammatory prostaglandins. Here we report stable-isotope GC-MS and LC-MS/MS assays for the reliable measurement of MAGL activity. The assays utilize deuterium-labeled 2AG (d 8 -2AG; 10μM) as the MAGL substrate and measure deuterium-labeled AA (d 8 -AA; range 0-1μM) as the MAGL product. Unlabelled AA (d 0 -AA, 1μM) serves as the internal standard. d 8 -AA and d 0 -AA are extracted from the aqueous buffered incubation mixtures by ethyl acetate. Upon solvent evaporation the residue is reconstituted in the mobile phase prior to LC-MS/MS analysis or in anhydrous acetonitrile for GC-MS analysis. LC-MS/MS analysis is performed in the negative electrospray ionization mode by selected-reaction monitoring the mass transitions [M-H] - →[M-H - CO 2 ] - , i.e., m/z 311→m/z 267 for d 8 -AA and m/z 303→m/z 259 for d 0 -AA. Prior to GC-MS analysis d 8 -AA and d 0 -AA were converted to their pentafluorobenzyl (PFB) esters by means of PFB-Br. GC-MS analysis is performed in the electron-capture negative-ion chemical ionization mode by selected-ion monitoring the ions [M-PFB] - , i.e., m/z 311 for d 8 -AA and m/z 303 for d 0 -AA. The GC-MS and LC-MS/MS assays were cross-validated. Linear regression analysis between the concentration (range, 0-1μM) of d 8 -AA measured by LC-MS/MS (y) and that by GC-MS (x) revealed a straight line (r 2 =0.9848) with the regression equation y=0.003+0.898x, indicating a good agreement. In dog liver, we detected MAGL activity that was inhibitable by the MAGL inhibitor JZL-184. Exogenous eicosatetraynoic acid is suitable as internal standard for the quantitative determination

  20. Clustering Coefficients for Correlation Networks.

    Science.gov (United States)

    Masuda, Naoki; Sakaki, Michiko; Ezaki, Takahiro; Watanabe, Takamitsu

    2018-01-01

    Graph theory is a useful tool for deciphering structural and functional networks of the brain on various spatial and temporal scales. The clustering coefficient quantifies the abundance of connected triangles in a network and is a major descriptive statistics of networks. For example, it finds an application in the assessment of small-worldness of brain networks, which is affected by attentional and cognitive conditions, age, psychiatric disorders and so forth. However, it remains unclear how the clustering coefficient should be measured in a correlation-based network, which is among major representations of brain networks. In the present article, we propose clustering coefficients tailored to correlation matrices. The key idea is to use three-way partial correlation or partial mutual information to measure the strength of the association between the two neighboring nodes of a focal node relative to the amount of pseudo-correlation expected from indirect paths between the nodes. Our method avoids the difficulties of previous applications of clustering coefficient (and other) measures in defining correlational networks, i.e., thresholding on the correlation value, discarding of negative correlation values, the pseudo-correlation problem and full partial correlation matrices whose estimation is computationally difficult. For proof of concept, we apply the proposed clustering coefficient measures to functional magnetic resonance imaging data obtained from healthy participants of various ages and compare them with conventional clustering coefficients. We show that the clustering coefficients decline with the age. The proposed clustering coefficients are more strongly correlated with age than the conventional ones are. We also show that the local variants of the proposed clustering coefficients (i.e., abundance of triangles around a focal node) are useful in characterizing individual nodes. In contrast, the conventional local clustering coefficients were strongly

  1. Clustering Coefficients for Correlation Networks

    Directory of Open Access Journals (Sweden)

    Naoki Masuda

    2018-03-01

    Full Text Available Graph theory is a useful tool for deciphering structural and functional networks of the brain on various spatial and temporal scales. The clustering coefficient quantifies the abundance of connected triangles in a network and is a major descriptive statistics of networks. For example, it finds an application in the assessment of small-worldness of brain networks, which is affected by attentional and cognitive conditions, age, psychiatric disorders and so forth. However, it remains unclear how the clustering coefficient should be measured in a correlation-based network, which is among major representations of brain networks. In the present article, we propose clustering coefficients tailored to correlation matrices. The key idea is to use three-way partial correlation or partial mutual information to measure the strength of the association between the two neighboring nodes of a focal node relative to the amount of pseudo-correlation expected from indirect paths between the nodes. Our method avoids the difficulties of previous applications of clustering coefficient (and other measures in defining correlational networks, i.e., thresholding on the correlation value, discarding of negative correlation values, the pseudo-correlation problem and full partial correlation matrices whose estimation is computationally difficult. For proof of concept, we apply the proposed clustering coefficient measures to functional magnetic resonance imaging data obtained from healthy participants of various ages and compare them with conventional clustering coefficients. We show that the clustering coefficients decline with the age. The proposed clustering coefficients are more strongly correlated with age than the conventional ones are. We also show that the local variants of the proposed clustering coefficients (i.e., abundance of triangles around a focal node are useful in characterizing individual nodes. In contrast, the conventional local clustering coefficients

  2. Clustering Coefficients for Correlation Networks

    Science.gov (United States)

    Masuda, Naoki; Sakaki, Michiko; Ezaki, Takahiro; Watanabe, Takamitsu

    2018-01-01

    Graph theory is a useful tool for deciphering structural and functional networks of the brain on various spatial and temporal scales. The clustering coefficient quantifies the abundance of connected triangles in a network and is a major descriptive statistics of networks. For example, it finds an application in the assessment of small-worldness of brain networks, which is affected by attentional and cognitive conditions, age, psychiatric disorders and so forth. However, it remains unclear how the clustering coefficient should be measured in a correlation-based network, which is among major representations of brain networks. In the present article, we propose clustering coefficients tailored to correlation matrices. The key idea is to use three-way partial correlation or partial mutual information to measure the strength of the association between the two neighboring nodes of a focal node relative to the amount of pseudo-correlation expected from indirect paths between the nodes. Our method avoids the difficulties of previous applications of clustering coefficient (and other) measures in defining correlational networks, i.e., thresholding on the correlation value, discarding of negative correlation values, the pseudo-correlation problem and full partial correlation matrices whose estimation is computationally difficult. For proof of concept, we apply the proposed clustering coefficient measures to functional magnetic resonance imaging data obtained from healthy participants of various ages and compare them with conventional clustering coefficients. We show that the clustering coefficients decline with the age. The proposed clustering coefficients are more strongly correlated with age than the conventional ones are. We also show that the local variants of the proposed clustering coefficients (i.e., abundance of triangles around a focal node) are useful in characterizing individual nodes. In contrast, the conventional local clustering coefficients were strongly

  3. Converting Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2013-01-01

    are suggested: An optimization method for the surface impedances for locally reacting absorbers, the flow resistivity for extendedly reacting absorbers, and the flow resistance for fabrics. With four porous type absorbers, the conversion methods are validated. For absorbers backed by a rigid wall, the surface...... coefficients to random incidence absorption coefficients are proposed. The overestimations of the Sabine absorption coefficient are investigated theoretically based on Miki's model for porous absorbers backed by a rigid wall or an air cavity, resulting in conversion factors. Additionally, three optimizations...... impedance optimization produces the best results, while the flow resistivity optimization also yields reasonable results. The flow resistivity and flow resistance optimization for extendedly reacting absorbers are also found to be successful. However, the theoretical conversion factors based on Miki's model...

  4. Studies on the use of surface active agents for the removal of some pollutants from dilute aqueous solutions: foam separation techniques and sorption by sorbents synthesized from Silicious materials and surfactants

    International Nuclear Information System (INIS)

    Abd Elsalam, M.R.M.

    2010-01-01

    The increasing concern towards protection of the environment and optimization of a wide range of industrial processes and activities in both nuclear and non-nuclear fields imposes the need for the development of advanced separation processes in particular for treatment of liquid wastes and effluents.The work presented in this thesis will address the above objective with respect to the removal, from aqueous solutions, of two types of hazardous pollutants: chemical (dyes) and radiological (radionuclides) using two relatively modern separation techniques: ion flotation and adsorption onto a synthesized organo-clay. It will also include the results of treatment of dye-contaminated wastewater and mixed radioactive process wastewater, containing a toxic dye in addition to the radionuclides.The thesis comprises four chapters. Literature on dye separation by (i) ion flotation and (II) adsorption onto organo-clays are reviewed in the introductory section of chapter III and of chapter IV, respectively.

  5. Dilute Surfactant Methods for Carbonate Formations

    Energy Technology Data Exchange (ETDEWEB)

    Kishore K. Mohanty

    2006-02-01

    There are many fractured carbonate reservoirs in US (and the world) with light oil. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). The process of using dilute anionic surfactants in alkaline solutions has been investigated in this work for oil recovery from fractured oil-wet carbonate reservoirs both experimentally and numerically. This process is a surfactant-aided gravity drainage where surfactant diffuses into the matrix, lowers IFT and contact angle, which decrease capillary pressure and increase oil relative permeability enabling gravity to drain the oil up. Anionic surfactants have been identified which at dilute concentration of 0.05 wt% and optimal salinity can lower the interfacial tension and change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant DTAB with a West Texas crude oil. The force of adhesion in AFM of oil-wet regions changes after anionic surfactant treatment to values similar to those of water-wet regions. The AFM topography images showed that the oil-wetting material was removed from the surface by the anionic surfactant treatment. Adsorption studies indicate that the extent of adsorption for anionic surfactants on calcite minerals decreases with increase in pH and with decrease in salinity. Surfactant adsorption can be minimized in the presence of Na{sub 2}CO{sub 3}. Laboratory-scale surfactant brine imbibition experiments give high oil recovery (20-42% OOIP in 50 days; up to 60% in 200 days) for initially oil-wet cores through wettability alteration and IFT reduction. Small (<10%) initial gas saturation does not affect significantly the rate of oil recovery in the imbibition process, but larger gas saturation decreases the oil recovery rate. As the core permeability decreases, the rate of oil recovery reduces

  6. Criopreservação do sêmen de curimba (Prochilodus lineatus mediante adição de diferentes diluidores, ativadores e crioprotetores Cryopreservation of curimba (Prochilodus lineatus semen after addition of different diluters, activators and cryoprotectants

    Directory of Open Access Journals (Sweden)

    Luis David Solis Murgas

    2007-06-01

    Full Text Available Amostras de sêmen de cinco espécimes de Prochilodus lineatus (Valencienes, 1847 foram utilizadas para avaliação dos efeitos tóxicos e crioprotetores de seis soluções à base de BTS (Beltsville Thawing Solution® 4,5% enriquecidas com metanol e DMSO nas concentrações de 10% (A = BTS 4,5% + Metanol 10%; B = BTS 4,5% + DMSO 10%; C = BTS 4,5% + KCl 0,072% + metanol 10%; D = BTS 4,5% + KCl 0,072% + DMSO 10%; E = BTS 4,5% + KI 0,036% + metanol 10%; e F = BTS 4,5% + KI 0,036% + DMSO 10%. Foram avaliadas ainda três soluções ativadoras (água destilada, NaHCO3 60 mM e NaHCO3 119 mM, antes e após o congelamento. Estudaram-se a taxa e a duração da motilidade espermática. Não houve diferença significativa entre as soluções crioprotetoras utilizadas. O sêmen ativado por NaHCO3 60 e 119 mM apresentou as maiores taxas de motilidade espermática. A ativação por NaHCO3 119 mM possibilitou as maiores durações de motilidade no sêmen de P. lineatus.Semen samples of five specimens of Prochilodus lineatus (Valencienes, 1847 were used to test the toxic and cryoprotectants effects of six solutions based on BTS (Beltsville Thawing Solution® 4.5%: A - BTS 4.5% + Methanol 10%; B - BTS 4.5% + DMSO 10%; C - BTS 4.5% + KCl 0.072% + Methanol 10%; D - BTS 4.5% + KCl 0.072% + DMSO 10%; E - BTS 4.5% + KI 0.036% + Methanol 10% and F - BTS 4.5% + KI 0.036% + DMSO 10%. The effect of other three activator solutions (Distillated Water, NaHCO3 60 mM and NaHCO3 119 mM on the rate and duration of sperm motility were also evaluated before and after freezing. No significant differences were observed among the cryoprotectant solutions. Sperm motility rates for P. lineatus were higher for semen activated by NaHCO3 60mM and NaHCO3 119mM, which propitiated the highest sperm motility duration.

  7. Rate coefficient for the reaction N + NO

    Science.gov (United States)

    Fox, J. L.

    1994-01-01

    Evidence has been advanced that the rate coefficient for the reaction N + NO right arrow N2 + O has a small positive temperature dependence at the high temperatures (900 to 1500 K) that prevail in the terrestrial middle and upper thermosphere by Siskind and Rusch (1992), and at the low temperatures (100 to 200 K) of the Martian lower thermosphere by Fox (1993). Assuming that the rate coefficient recommended by the Jet Propulsion Laboratory evaluation (DeMore et al., 1992) is accurate at 300 K, we derive here the low temperature value of the activation energy for this reaction and thus the rate coefficient that best fits the Viking 1 measured NO densities. We find that the fit is acceptable for a rate coefficient of about 1.3 x 10(exp -10)(T/300)(exp 0.5)exp(-400/T) and better for a value of about 2.5 x 10(exp -10)(T/300)(exp 0.5)exp(-600/T)cu cm/s.

  8. Power coefficient anomaly in JOYO

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, H

    1980-12-15

    Operation of the JOYO experimental fast reactor with the MK-I core has been divided into two phases: (1) 50 MWt power ascension and operation; and (2) 75 MWt power ascension and operation. The 50 MWt power-up tests were conducted in August 1978. In these tests, the measured reactivity loss due to power increases from 15 MWt to 50 MWt was 0.28% ..delta.. K/K, and agreed well with the predicted value of 0.27% ..delta.. K/K. The 75 MWt power ascension tests were conducted in July-August 1979. In the process of the first power increase above 50 MWt to 65 MWt conducted on July 11, 1979, an anomalously large negative power coefficient was observed. The value was about twice the power coefficient values measured in the tests below 50 MW. In order to reproduce the anomaly, the reactor power was decreased and again increased up to the maximum power of 65 MWt. However, the large negative power coefficient was not observed at this time. In the succeeding power increase from 65 MWt to 75 MWt, a similar anomalous power coefficient was again observed. This anomaly disappeared in the subsequent power ascensions to 75 MWt, and the magnitude of the power coefficient gradually decreased with power cycles above the 50 MWt level.

  9. Dilute solution properties of canary seed (Phalaris canariensis) starch in comparison to wheat starch.

    Science.gov (United States)

    Irani, Mahdi; Razavi, Seyed M A; Abdel-Aal, El-Sayed M; Hucl, Pierre; Patterson, Carol Ann

    2016-06-01

    Dilute solution properties of an unknown starch are important to understand its performance and applications in food and non-food industries. In this paper, rheological and molecular properties (intrinsic viscosity, molecular weight, shape factor, voluminosity, conformation and coil overlap parameters) of the starches from two hairless canary seed varieties (CO5041 & CDC Maria) developed for food use were evaluated in the dilute regime (Starch dispersions in DMSO (0.5g/dl)) and compared with wheat starch (WS). The results showed that Higiro model is the best among five applied models for intrinsic viscosity determination of canary seed starch (CSS) and WS on the basis of coefficient of determination (R(2)) and root mean square error (RMSE). WS sample showed higher intrinsic viscosity value (1.670dl/g) in comparison to CSS samples (1.325-1.397dl/g). Berry number and the slope of master curve demonstrated that CSS and WS samples were in dilute domain without entanglement occurrence. The shape factor suggested spherical and ellipsoidal structure for CO5041 starch and ellipsoidal for CDC Maria starch and WS. The molecular weight, coil radius and coil volume of CSSs were smaller than WS. The behavior and molecular characterization of canary seed starch showed its unique properties compared with wheat starch. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Radiotracer Dilution Method for Mercury Inventory Study in Electrolytic Cells

    Science.gov (United States)

    Sugiharto, Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul; Santoso, Sigit Budi; Abidin, Zainal; Santoso, Gatot Budi

    2010-06-01

    Purpose of the experiment is to demonstrate feasibility the use of radiotracer to measure weight of mercury in electrolytic cells of soda industry. The weight of mercury in each cell of the plant is designed approximately 1700 kg. Radiotracer is prepared by mixing 203 Hg radioactive mercury with 2400 g of inactive mercury in a bath. The respective precisely weighted mercury aliquots to be injected into the cells are prepared by pouring approximately 130 g of radioactive mercury taken from the bath into 13 standard vials, in accordance with the number of the cells tested. Four standard references prepared by further dilution of ±2 g active mercury taken from the bath to obtain the dilution factors range of 12,000 to 20,000 from which the calibration graph is constructed. The injection process is conducting by pouring the radioactive mercury from aliquots into the flowing mercury at the inlet side of the cell and allows them to mix thoroughly. It is assumed that the mass of the radiotracer injected into a closed system remains constant, at least during the period of the test. From this experiment it was observed that the mixing time is two days after injection of radioactive mercury. The inactive mercury in each electrolytic cell calculated by the radiotracer method is of the range 1351.529 kg to 1966.354 kg with maximum error (95% confidence) is 1.52 %. The accuracy of measurement of the present method is better than gravimetric one which accounts 4 % of error on average.

  11. Radiotracer Dilution Method for Mercury Inventory Study in Electrolytic Cells

    International Nuclear Information System (INIS)

    Sugiharto; Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul; Santoso, Sigit Budi; Abidin, Zainal; Santoso, Gatot Budi

    2010-01-01

    Purpose of the experiment is to demonstrate feasibility the use of radiotracer to measure weight of mercury in electrolytic cells of soda industry. The weight of mercury in each cell of the plant is designed approximately 1700 kg. Radiotracer is prepared by mixing 203 Hg radioactive mercury with 2400 g of inactive mercury in a bath. The respective precisely weighted mercury aliquots to be injected into the cells are prepared by pouring approximately 130 g of radioactive mercury taken from the bath into 13 standard vials, in accordance with the number of the cells tested. Four standard references prepared by further dilution of ±2 g active mercury taken from the bath to obtain the dilution factors range of 12,000 to 20,000 from which the calibration graph is constructed. The injection process is conducting by pouring the radioactive mercury from aliquots into the flowing mercury at the inlet side of the cell and allows them to mix thoroughly. It is assumed that the mass of the radiotracer injected into a closed system remains constant, at least during the period of the test. From this experiment it was observed that the mixing time is two days after injection of radioactive mercury. The inactive mercury in each electrolytic cell calculated by the radiotracer method is of the range 1351.529 kg to 1966.354 kg with maximum error (95% confidence) is 1.52 %. The accuracy of measurement of the present method is better than gravimetric one which accounts 4 % of error on average.

  12. Some local dilution transient in a pressurized water reactor

    International Nuclear Information System (INIS)

    Jacobson, S.

    1989-01-01

    Reactivity accidents are important in the safety analysis of a pressurized water reactor. In this anlysis ejected control rod, steam line break, start of in-active loop and boron dilution accidents are usually dealt with. However, in the analysis is not included what reactivity excursions might happen when a zone,depleted of boron passes the reactor core. This thesis investigates during what operation and emergency conditions diluted zones might exist in a pressurized water reactor and what should be the maximum volumes for then. The limiting transport means are also established in terms of reactivty addition, for the depleted zones. In order to describe the complicated mixing process in the reactor vessel during such a transportation, a typical 3-loop reactor vessel has been modulated by means of TRAC-PF1's VESSEL component. Three cases have been analysed. In the first case the reactor is in a cold condition and the ractor coolant has boron concentration of 2000 ppm. To the reactor vessel is injected an clean water colume of 14 m 3 . In the two other cases the reactor is close to hot shutdown and borated to 850 ppm. To the reactor vessel is added 41 and 13 m 3 clean water, respectively. In the thesis is shown what spatial distribution the depleted zone gets when passing through the reactor vessel in the three cases. The boron concentration in the first case did not decrease the values which would bring the reactor to critical condition. For case two was shown by means of TRAC's point kinetics model that the reactor reaches prompt criticality after 16.03 seconds after starting of the reactor coolant pump. Another prompt criticality occured two seconds later. The total energy developed during the two power escalations were about 55 GJ. A comparision with the criteria used to evaluate the ejected control rod reactivity transient showed that none of these criteria were exceeded. (64 figs.)

  13. Dilute antiferromagnetism in magnetically doped phosphorene

    Directory of Open Access Journals (Sweden)

    Andrew Allerdt

    2017-11-01

    Full Text Available We study the competition between Kondo physics and indirect exchange on monolayer black phos-phorous using a realistic description of the band structure in combination with the density matrixrenormalization group (DMRG method. The Hamiltonian is reduced to a one-dimensional problemvia an exact canonical transformation that makes it amenable to DMRG calculations, yielding exactresults that fully incorporate the many-body physics. We find that a perturbative description of theproblem is not appropriate and cannot account for the slow decay of the correlations and the completelack of ferromagnetism. In addition, at some particular distances, the impurities decouple formingtheir own independent Kondo states. This can be predicted from the nodes of the Lindhard function.Our results indicate a possible route toward realizing dilute anti-ferromagnetism in phosphorene. Received: 19 September 2017, Accepted: 12 October 2017; Edited by: K. Hallberg; DOI: http://dx.doi.org/10.4279/PIP.090008 Cite as: A Allerdt, A E Feiguin, Papers in Physics 9, 090008 (2017

  14. Behaviour of humic-bentonite aggregates in diluted suspensions ...

    African Journals Online (AJOL)

    Formation and disaggregation of micron-size aggregates in a diluted suspension made up of HSs and bentonite (B) were studied by tracing distribution of aggregate sizes and their counts in freshly prepared and aged suspensions, and at high (10 000) and low (1.0) [HS]/[B] ratios. Diluted HSB suspensions are unstable ...

  15. Dilution in Transition Zone between Rising Plumes and Surface Plumes

    DEFF Research Database (Denmark)

    Larsen, Torben

    2004-01-01

    The papers presents some physical experiments with the dilution of sea outfall plumes with emphasize on the transition zone where the relative fast flowing vertical plume turns to a horizontal surface plume following the slow sea surface currents. The experiments show that a considerable dilution...

  16. Magnetic ordering in dilute YTb and YEr alloys

    International Nuclear Information System (INIS)

    Rainford, B.D.; Kilcoyne, S.H.; Mohammed, K.A.; Lanchester, P.C.; Stanley, H.B.; Caudron, R.

    1988-01-01

    Dilute YEr alloys (Er concentration between 3% and 10%) show the existence of sinusoidally modulated antiferromagnetism down to the lowest impurity concentrations studied. Extrapolation of the Neel temperatures for both YEr and YTb suggests a critical concentration is ≅ 0.8% Tb, Er. Ordering in such dilute alloys may result from exchange enhancement in the yttrium host

  17. Magnetic ordering in dilute YTb and YEr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rainford, B.D.; Kilcoyne, S.H.; Mohammed, K.A.; Lanchester, P.C.; Stanley, H.B.; Caudron, R.

    1988-12-01

    Dilute YEr alloys (Er concentration between 3% and 10%) show the existence of sinusoidally modulated antiferromagnetism down to the lowest impurity concentrations studied. Extrapolation of the Neel temperatures for both YEr and YTb suggests a critical concentration is /approx equal/ 0.8% Tb, Er. Ordering in such dilute alloys may result from exchange enhancement in the yttrium host.

  18. The Melt-Dilute Treatment Technology Offgas Development Status Report

    International Nuclear Information System (INIS)

    Adams, T. M.

    1999-01-01

    The melt-dilute treatment technology is being developed to facilitate the ultimate disposition of highly enriched Al-Base DOE spent nuclear fuels in a geologic repository such as that proposed for Yucca Mountain. The melt-dilute process is a method of preparing DOE spent nuclear fuel for long term storage

  19. Near-wall molecular ordering of dilute ionic liquids

    NARCIS (Netherlands)

    Jitvisate, Monchai; Seddon, James Richard Thorley

    2017-01-01

    The interfacial behavior of ionic liquids promises tunable lubrication as well as playing an integral role in ion diffusion for electron transfer. Diluting the ionic liquids optimizes bulk parameters, such as electric conductivity, and one would expect dilution to disrupt the near-wall molecular

  20. Effect of dietary dilution of energy and nutrients during different ...

    African Journals Online (AJOL)

    A completely randomized design was conducted to evaluate the effect of dietary dilution of energy and nutrients during different growing periods on compensatory growth of Ross broilers. Four replicant pens were assigned per seven treatments. Chicks in each treatment received concentrated and diluted diets in different ...

  1. The dilute random field Ising model by finite cluster approximation

    International Nuclear Information System (INIS)

    Benyoussef, A.; Saber, M.

    1987-09-01

    Using the finite cluster approximation, phase diagrams of bond and site diluted three-dimensional simple cubic Ising models with a random field have been determined. The resulting phase diagrams have the same general features for both bond and site dilution. (author). 7 refs, 4 figs

  2. Enhancement of surface magnetism due to bulk bond dilution

    International Nuclear Information System (INIS)

    Tsallis, C.; Sarmento, E.F.; Albuquerque, E.L. de

    1985-01-01

    Within a renormalization group scheme, the phase diagram of a semi-infinite simple cubic Ising ferromagnet is discussed, with arbitrary surface and bulk coupling constants, and including possible dilution of the bulk bonds. It is obtained that dilution makes easier the appearance of surface magnetism in the absence of bulk magnetism. (Author) [pt

  3. Analysis of internal conversion coefficients

    International Nuclear Information System (INIS)

    Coursol, N.; Gorozhankin, V.M.; Yakushev, E.A.; Briancon, C.; Vylov, Ts.

    2000-01-01

    An extensive database has been assembled that contains the three most widely used sets of calculated internal conversion coefficients (ICC): [Hager R.S., Seltzer E.C., 1968. Internal conversion tables. K-, L-, M-shell Conversion coefficients for Z=30 to Z=103, Nucl. Data Tables A4, 1-237; Band I.M., Trzhaskovskaya M.B., 1978. Tables of gamma-ray internal conversion coefficients for the K-, L- and M-shells, 10≤Z≤104, Special Report of Leningrad Nuclear Physics Institute; Roesel F., Fries H.M., Alder K., Pauli H.C., 1978. Internal conversion coefficients for all atomic shells, At. Data Nucl. Data Tables 21, 91-289] and also includes new Dirac-Fock calculations [Band I.M. and Trzhaskovskaya M.B., 1993. Internal conversion coefficients for low-energy nuclear transitions, At. Data Nucl. Data Tables 55, 43-61]. This database is linked to a computer program to plot ICCs and their combinations (sums and ratios) as a function of Z and energy, as well as relative deviations of ICC or their combinations for any pair of tabulated data. Examples of these analyses are presented for the K-shell and total ICCs of the gamma-ray standards [Hansen H.H., 1985. Evaluation of K-shell and total internal conversion coefficients for some selected nuclear transitions, Eur. Appl. Res. Rept. Nucl. Sci. Tech. 11.6 (4) 777-816] and for the K-shell and total ICCs of high multipolarity transitions (total, K-, L-, M-shells of E3 and M3 and K-shell of M4). Experimental data sets are also compared with the theoretical values of these specific calculations

  4. Algebraic polynomials with random coefficients

    Directory of Open Access Journals (Sweden)

    K. Farahmand

    2002-01-01

    Full Text Available This paper provides an asymptotic value for the mathematical expected number of points of inflections of a random polynomial of the form a0(ω+a1(ω(n11/2x+a2(ω(n21/2x2+…an(ω(nn1/2xn when n is large. The coefficients {aj(w}j=0n, w∈Ω are assumed to be a sequence of independent normally distributed random variables with means zero and variance one, each defined on a fixed probability space (A,Ω,Pr. A special case of dependent coefficients is also studied.

  5. Transport coefficients of strongly interacting matter

    International Nuclear Information System (INIS)

    Heckmann, Klaus

    2011-01-01

    In this thesis, we investigate the dissipative transport phenomena of strongly interacting matter. The special interest is in the shear viscosity and its value divided by entropy density. The performed calculations are based on effective models for Quantum Chromodynamics, mostly focused on the 2-flavor Nambu-Jona-Lasinio model. This allows us to study the hadronic sector as well as the quark sector within one single model. We expand the models up to next-to-leading order in inverse numbers of colors. We present different possibilities of calculating linear transport coefficients and give an overview over qualitative properties as well as over recent ideas concerning ideal fluids. As present methods are not able to calculate the quark two-point function in Minkowski space-time in the self-consistent approximation scheme of the Nambu-Jona-Lasinio model, a new method for this purpose is developed. This self-energy parametrization method is applied to the expansion scheme, yielding the quark spectral function with meson back-coupling effects. The usage of this spectral function in the transport calculation is only one result of this work. We also test the application of different transport approaches in the NJL model, and find an interesting behavior of the shear viscosity at the critical end point of the phase diagram. We also use the NJL model to calculate the viscosity of a pion gas in the dilute regime. After an analysis of other models for pions and their interaction, we find that the NJL-result leads to an important modification of transport properties in comparison with the calculations which purely rely on pion properties in the vacuum. (orig.)

  6. Dynamic dilution exponent in monodisperse entangled polymer solutions

    DEFF Research Database (Denmark)

    Shahid, T.; Huang, Qian; Oosterlinck, F.

    2017-01-01

    of concentration but also depends on the molar mass of the chains. While the proposed approach successfully explains the viscoelastic properties of a large number of semi-dilute solutions of polymers in their own oligomers, important discrepancies are found for semi-dilute entangled polymers in small-molecule......We study and model the linear viscoelastic properties of several entangled semi-dilute and concentrated solutions of linear chains of different molar masses and at different concentrations dissolved in their oligomers. We discuss the dilution effect of the oligomers on the entangled long chains....... In particular, we investigate the influence of both concentration and molar mass on the value of the effective dynamic dilution exponent determined from the level of the storage plateau at low and intermediate frequencies. We show that the experimental results can be quantitatively explained by considering...

  7. The dilution effect on the extinction of wall diffusion flame

    Directory of Open Access Journals (Sweden)

    Ghiti Nadjib

    2014-12-01

    Full Text Available The dynamic process of the interaction between a turbulent jet diffusion methane flame and a lateral wall was experimentally studied. The evolution of the flame temperature field with the Nitrogen dilution of the methane jet flame was examined. The interaction between the diffusion flame and the lateral wall was investigated for different distance between the wall and the central axes of the jet flame. The dilution is found to play the central role in the flame extinction process. The flame response as the lateral wall approaches from infinity and the increasing of the dilution rate make the flame extinction more rapid than the flame without dilution, when the nitrogen dilution rate increase the flame temperature decrease.

  8. Extended aroma extract dilution analysis profile of Shiikuwasha (Citrus depressa Hayata pulp essential oil

    Directory of Open Access Journals (Sweden)

    Yonathan Asikin

    2018-01-01

    Full Text Available Shiikuwasha pulp is an important raw material for producing citrus essential oils. The volatile aroma composition of pulp essential oil was evaluated using gas chromatography (GC methods, and its aroma profile was assessed using GC-olfactometry with an extended aroma extract dilution analysis (AEDA technique in regard to alterations of odor strength and sensorial perception throughout serial dilution steps. The essential oil comprised a mixture of 55 aroma compounds, including monoterpene hydrocarbon, sesquiterpene hydrocarbon, alcohol, aldehyde, ester, and oxide compounds. The predominant compounds were limonene [57.36% (4462.80 mg/100 g of pulp] and γ-terpinene [25.14% (1956.21 mg/100 g of pulp]. However, linalool was identified as one of the key aroma components providing the highest flavor dilution factor in AEDA, whilst three sesquiterpene hydrocarbons (δ-elemene, germacrene B, and bicyclosesquiphellandrene and two esters (heptyl acetate and decyl acetate had superior relative flavor activities. The extended AEDA profile identified variations in assessed odor perceptions, intensity, and duration of aroma components over dilution, whereas the 12 most odor-active compounds showed comparable odor strengths.

  9. Calculation of NaCl, KCl and LiCl Salts Activity Coefficients in Polyethylene Glycol (PEG4000)-Water System Using Modified PHSC Equation of State, Extended Debye-Hückel Model and Pitzer Model

    Science.gov (United States)

    Marjani, Azam

    2016-07-01

    For biomolecules and cell particles purification and separation in biological engineering, besides the chromatography as mostly applied process, aqueous two-phase systems (ATPS) are of the most favorable separation processes that are worth to be investigated in thermodynamic theoretically. In recent years, thermodynamic calculation of ATPS properties has attracted much attention due to their great applications in chemical industries such as separation processes. These phase calculations of ATPS have inherent complexity due to the presence of ions and polymers in aqueous solution. In this work, for target ternary systems of polyethylene glycol (PEG4000)-salt-water, thermodynamic investigation for constituent systems with three salts (NaCl, KCl and LiCl) has been carried out as PEG is the most favorable polymer in ATPS. The modified perturbed hard sphere chain (PHSC) equation of state (EOS), extended Debye-Hückel and Pitzer models were employed for calculation of activity coefficients for the considered systems. Four additional statistical parameters were considered to ensure the consistency of correlations and introduced as objective functions in the particle swarm optimization algorithm. The results showed desirable agreement to the available experimental data, and the order of recommendation of studied models is PHSC EOS > extended Debye-Hückel > Pitzer. The concluding remark is that the all the employed models are reliable in such calculations and can be used for thermodynamic correlation/predictions; however, by using an ion-based parameter calculation method, the PHSC EOS reveals both reliability and universality of applications.

  10. Selective on site separation and detection of molecules in diluted solutions with super-hydrophobic clusters of plasmonic nanoparticles

    KAUST Repository

    Gentile, Francesco T.; Coluccio, Maria Laura; Proietti Zaccaria, Remo; Francardi, Marco; Cojoc, Gheorghe; Perozziello, Gerardo; Raimondo, Raffaella; Candeloro, Patrizio; Di Fabrizio, Enzo M.

    2014-01-01

    Super-hydrophobic surfaces are bio-inspired interfaces with a superficial texture that, in its most common evolution, is formed by a periodic lattice of silicon micro-pillars. Similar surfaces reveal superior properties compared to conventional flat surfaces, including very low friction coefficients. In this work, we modified meso-porous silicon micro-pillars to incorporate networks of metal nano-particles into the porous matrix. In doing so, we obtained a multifunctional-hierarchical system in which (i) at a larger micrometric scale, the super-hydrophobic pillars bring the molecules dissolved in an ultralow-concentration droplet to the active sites of the device, (ii) at an intermediate meso-scale, the meso-porous silicon film adsorbs the low molecular weight content of the solution and, (iii) at a smaller nanometric scale, the aggregates of silver nano-particles would measure the target molecules with unprecedented sensitivity. In the results, we demonstrated how this scheme can be utilized to isolate and detect small molecules in a diluted solution in very low abundance ranges. The presented platform, coupled to Raman or other spectroscopy techniques, is a realistic candidate for the protein expression profiling of biological fluids. © 2014 the Partner Organisations.

  11. Low frequency complex dielectric (conductivity) response of dilute clay suspensions: Modeling and experiments.

    Science.gov (United States)

    Hou, Chang-Yu; Feng, Ling; Seleznev, Nikita; Freed, Denise E

    2018-04-11

    In this work, we establish an effective medium model to describe the low-frequency complex dielectric (conductivity) dispersion of dilute clay suspensions. We use previously obtained low-frequency polarization coefficients for a charged oblate spheroidal particle immersed in an electrolyte as the building block for the Maxwell Garnett mixing formula to model the dilute clay suspension. The complex conductivity phase dispersion exhibits a near-resonance peak when the clay grains have a narrow size distribution. The peak frequency is associated with the size distribution as well as the shape of clay grains and is often referred to as the characteristic frequency. In contrast, if the size of the clay grains has a broad distribution, the phase peak is broadened and can disappear into the background of the canonical phase response of the brine. To benchmark our model, the low-frequency dispersion of the complex conductivity of dilute clay suspensions is measured using a four-point impedance measurement, which can be reliably calibrated in the frequency range between 0.1 Hz and 10 kHz. By using a minimal number of fitting parameters when reliable information is available as input for the model and carefully examining the issue of potential over-fitting, we found that our model can be used to fit the measured dispersion of the complex conductivity with reasonable parameters. The good match between the modeled and experimental complex conductivity dispersion allows us to argue that our simplified model captures the essential physics for describing the low-frequency dispersion of the complex conductivity of dilute clay suspensions. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Irrational "Coefficients" in Renaissance Algebra.

    Science.gov (United States)

    Oaks, Jeffrey A

    2017-06-01

    Argument From the time of al-Khwārizmī in the ninth century to the beginning of the sixteenth century algebraists did not allow irrational numbers to serve as coefficients. To multiply by x, for instance, the result was expressed as the rhetorical equivalent of . The reason for this practice has to do with the premodern concept of a monomial. The coefficient, or "number," of a term was thought of as how many of that term are present, and not as the scalar multiple that we work with today. Then, in sixteenth-century Europe, a few algebraists began to allow for irrational coefficients in their notation. Christoff Rudolff (1525) was the first to admit them in special cases, and subsequently they appear more liberally in Cardano (1539), Scheubel (1550), Bombelli (1572), and others, though most algebraists continued to ban them. We survey this development by examining the texts that show irrational coefficients and those that argue against them. We show that the debate took place entirely in the conceptual context of premodern, "cossic" algebra, and persisted in the sixteenth century independent of the development of the new algebra of Viète, Decartes, and Fermat. This was a formal innovation violating prevailing concepts that we propose could only be introduced because of the growing autonomy of notation from rhetorical text.

  13. Integer Solutions of Binomial Coefficients

    Science.gov (United States)

    Gilbertson, Nicholas J.

    2016-01-01

    A good formula is like a good story, rich in description, powerful in communication, and eye-opening to readers. The formula presented in this article for determining the coefficients of the binomial expansion of (x + y)n is one such "good read." The beauty of this formula is in its simplicity--both describing a quantitative situation…

  14. Dilute Oxygen Combustion Phase I Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, H.M.; Riley, M.F.; Kobayashi, H.

    1997-10-31

    A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions

  15. Dilute oxygen combustion. Phase I report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NO{sub x}) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NO{sub x} through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NO{sub x} production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature ({approximately}1366 K) oxidant (7-27% O{sub 2} vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d{sup +} scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d{sup +} scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW ({approximately}0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric

  16. Role reductants in dilute chemical decontamination formulations

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, S. [Univ. of New Brunswick (Canada). Dept. of Chemical Engineering; Srinivasan, M.P.; Narasimhan, S.V. [Bhabha Atomic Research Centre (BARC), Trombay, Mumbai (India). Water and Steam Chemistry Lab.; Raghavan, P.S. [Madras Christian Coll., Chennai (India); Gopalan, R. [Madras Christian Coll., Chennai (India). Dept. of Chemistry

    2004-10-01

    Iron(III) oxides are the major corrosion products formed in boiling water reactors. The iron(III) oxides are of two types, namely hematite ({alpha}-Fe{sub 2}O{sub 3}) and maghemite ({gamma}-Fe{sub 2}O{sub 3}). The dissolution of these oxides is in no way simple because of the labile nature of the Fe(III)-O bond towards the chelants. The leaching of metal ions is partially controlled by reductive dissolution. In order to understand the role of the reductant, it is essential to study the dissolution behaviour of a system like Fe{sub 2}O{sub 3}, which does not contain any Fe{sup 2+} in the crystal lattice. The present study was carried out with {gamma}-Fe{sub 2}O{sub 3} and dilute chemical decontamination (DCD) formulations containing ascorbic acid and citric acid with the addition of Fe(II)-L as a reductant. The chelants used for the dissolution process were nitrilotriacetic acid, 2,6-pyridinedicorboxylic acid and ethylenediaminetetraacetic acid. The {gamma}-Fe{sub 2}O{sub 3} was chosen since the earlier studies revealed that the dissolution kinetics of {alpha}-Fe{sub 2}O{sub 3} is slow and it is difficult to dissolve even by strong complexing agents, whereas {gamma}-Fe{sub 2}O{sub 3} dissolution is comparatively easier. This is due to the structural difference between these two oxides. The studies also revealed that the dissolution was partly influenced by the nature of the chelating agents but mainly controlled by the power of the reductants used in the formulation. The dissolution behaviour of {gamma}-Fe{sub 2}O{sub 3} under various experimental conditions is discussed and compared with that of magnetite in order to arrive at a suitable mechanism for the dissolution of iron oxides and emphasize the role of reductants in DCD formulations. (orig.)

  17. Ionic liquids behave as dilute electrolyte solutions

    Science.gov (United States)

    Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

    2013-01-01

    We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

  18. A dilute-and-shoot flow-injection tandem mass spectrometry method for quantification of phenobarbital in urine.

    Science.gov (United States)

    Alagandula, Ravali; Zhou, Xiang; Guo, Baochuan

    2017-01-15

    Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is the gold standard of urine drug testing. However, current LC-based methods are time consuming, limiting the throughput of MS-based testing and increasing the cost. This is particularly problematic for quantification of drugs such as phenobarbital, which is often analyzed in a separate run because they must be negatively ionized. This study examined the feasibility of using a dilute-and-shoot flow-injection method without LC separation to quantify drugs with phenobarbital as a model system. Briefly, a urine sample containing phenobarbital was first diluted by 10 times, followed by flow injection of the diluted sample to mass spectrometer. Quantification and detection of phenobarbital were achieved by an electrospray negative ionization MS/MS system operated in the multiple reaction monitoring (MRM) mode with the stable-isotope-labeled drug as internal standard. The dilute-and-shoot flow-injection method developed was linear with a dynamic range of 50-2000 ng/mL of phenobarbital and correlation coefficient > 0.9996. The coefficients of variation and relative errors for intra- and inter-assays at four quality control (QC) levels (50, 125, 445 and 1600 ng/mL) were 3.0% and 5.0%, respectively. The total run time to quantify one sample was 2 min, and the sensitivity and specificity of the method did not deteriorate even after 1200 consecutive injections. Our method can accurately and robustly quantify phenobarbital in urine without LC separation. Because of its 2 min run time, the method can process 720 samples per day. This feasibility study shows that the dilute-and-shoot flow-injection method can be a general way for fast analysis of drugs in urine. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Use of diluted urine for cultivation of Chlorella vulgaris.

    Science.gov (United States)

    Jaatinen, Sanna; Lakaniemi, Aino-Maija; Rintala, Jukka

    2016-01-01

    Our aim was to study the biomass growth of microalga Chlorella vulgaris using diluted human urine as a sole nutrient source. Batch cultivations (21 days) were conducted in five different urine dilutions (1:25-1:300), in 1:100-diluted urine as such and with added trace elements, and as a reference, in artificial growth medium. The highest biomass density was obtained in 1:100-diluted urine with and without additional trace elements (0.73 and 0.60 g L(-1), respectively). Similar biomass growth trends and densities were obtained with 1:25- and 1:300-diluted urine (0.52 vs. 0.48 gVSS L(-1)) indicating that urine at dilution 1:25 can be used to cultivate microalgal based biomass. Interestingly, even 1:300-diluted urine contained sufficiently nutrients and trace elements to support biomass growth. Biomass production was similar despite pH-variation from < 5 to 9 in different incubations indicating robustness of the biomass growth. Ammonium formation did not inhibit overall biomass growth. At the beginning of cultivation, the majority of the biomass consisted of living algal cells, while towards the end, their share decreased and the estimated share of bacteria and cell debris increased.

  20. Incorporating an extended dendritic growth model into the CAFE model for rapidly solidified non-dilute alloys

    International Nuclear Information System (INIS)

    Ma, Jie; Wang, Bo; Zhao, Shunli; Wu, Guangxin; Zhang, Jieyu; Yang, Zhiliang

    2016-01-01

    We have extended the dendritic growth model first proposed by Boettinger, Coriell and Trivedi (here termed EBCT) for microstructure simulations of rapidly solidified non-dilute alloys. The temperature-dependent distribution coefficient, obtained from calculations of phase equilibria, and the continuous growth model (CGM) were adopted in the present EBCT model to describe the solute trapping behaviors. The temperature dependence of the physical properties, which were not used in previous dendritic growth models, were also considered in the present EBCT model. These extensions allow the present EBCT model to be used for microstructure simulations of non-dilute alloys. The comparison of the present EBCT model with the BCT model proves that the considerations of the distribution coefficient and physical properties are necessary for microstructure simulations, especially for small particles with high undercoolings. Finally, the EBCT model was incorporated into the cellular automaton-finite element (CAFE) model to simulate microstructures of gas-atomized ASP30 high speed steel particles that were then compared with experimental results. Both the simulated and experimental results reveal that a columnar dendritic microstructure preferentially forms in small particles and an equiaxed microstructure forms otherwise. The applications of the present EBCT model provide a convenient way to predict the microstructure of non-dilute alloys. - Highlights: • A dendritic growth model was developed considering non-equilibrium distribution coefficient. • The physical properties with temperature dependence were considered in the extended model. • The extended model can be used to non-dilute alloys and the extensions are necessary in small particles. • Microstructure of ASP30 steel was investigated using the present model and verified by experiment.

  1. Incorporating an extended dendritic growth model into the CAFE model for rapidly solidified non-dilute alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jie; Wang, Bo [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Zhao, Shunli [Research Institute, Baoshan Iron & Steel Co., Ltd, Shanghai 201900 (China); Wu, Guangxin [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Zhang, Jieyu, E-mail: zjy6162@staff.shu.edu.cn [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Yang, Zhiliang [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China)

    2016-05-25

    We have extended the dendritic growth model first proposed by Boettinger, Coriell and Trivedi (here termed EBCT) for microstructure simulations of rapidly solidified non-dilute alloys. The temperature-dependent distribution coefficient, obtained from calculations of phase equilibria, and the continuous growth model (CGM) were adopted in the present EBCT model to describe the solute trapping behaviors. The temperature dependence of the physical properties, which were not used in previous dendritic growth models, were also considered in the present EBCT model. These extensions allow the present EBCT model to be used for microstructure simulations of non-dilute alloys. The comparison of the present EBCT model with the BCT model proves that the considerations of the distribution coefficient and physical properties are necessary for microstructure simulations, especially for small particles with high undercoolings. Finally, the EBCT model was incorporated into the cellular automaton-finite element (CAFE) model to simulate microstructures of gas-atomized ASP30 high speed steel particles that were then compared with experimental results. Both the simulated and experimental results reveal that a columnar dendritic microstructure preferentially forms in small particles and an equiaxed microstructure forms otherwise. The applications of the present EBCT model provide a convenient way to predict the microstructure of non-dilute alloys. - Highlights: • A dendritic growth model was developed considering non-equilibrium distribution coefficient. • The physical properties with temperature dependence were considered in the extended model. • The extended model can be used to non-dilute alloys and the extensions are necessary in small particles. • Microstructure of ASP30 steel was investigated using the present model and verified by experiment.

  2. Dilution thermodynamics of the biologically relevant cation mixtures

    International Nuclear Information System (INIS)

    Kaczyński, Marek; Borowik, Tomasz; Przybyło, Magda; Langner, Marek

    2014-01-01

    Graphical abstract: - Highlights: • Dilution energetics of Ca 2+ can be altered by the aqueous phase ionic composition. • Dissipated heat upon Ca 2+ dilution is drastically reduced in the K + presence. • Reduction of the enthalpy change upon Ca 2+ dilution is K + concentration dependent. • The cooperativity of Ca 2+ hydration might be of great biological relevance providing a thermodynamic argument for the specific ionic composition of the intracellular environment. - Abstract: The ionic composition of intracellular space is rigorously controlled by a variety of processes consuming large quantities of energy. Since the energetic efficiency is an important evolutional criterion, therefore the ion fluxes within the cell should be optimized with respect to the accompanying energy consumption. In the paper we present the experimental evidence that the dilution enthalpies of the biologically relevant ions; i.e. calcium and magnesium depend on the presence of monovalent cations; i.e. sodium and potassium. The heat flow generated during the dilution of ionic mixtures was measured with the isothermal titration calorimetry. When calcium was diluted together with potassium the dilution enthalpy was drastically reduced as the function of the potassium concentration present in the solution. No such effect was observed when the potassium ions were substituted with sodium ones. When the dilution of magnesium was investigated the dependence of the dilution enthalpy on the accompanying monovalent cation was much weaker. In order to interpret experimental evidences the ionic cluster formation is postulated. The specific organization of such cluster should depend on ions charges, sizes and organization of the hydration layers

  3. Effect of hypothermic pulmonary artery flushing on capillary filtration coefficient.

    Science.gov (United States)

    Andrade, R S; Wangensteen, O D; Jo, J K; Tsai, M Y; Bolman, R M

    2000-07-27

    We previously demonstrated that surfactant dilution and inhibition occur immediately after pulmonary artery flushing with hypothermic modified Euro-Collins solution. Consequently, we speculated that increased capillary permeability contributed to these surfactant changes. To test this hypothesis, we evaluated the effects of hypothermic pulmonary artery flushing on the pulmonary capillary filtration coefficient (Kfc), and additionally performed a biochemical analysis of surfactant. We used a murine isolated, perfused lung model to measure the pulmonary capillary filtration coefficient and hemodynamic parameters, to determine the wet to dry weight ratio, and to evaluate surfactant by biochemical analysis of lung lavage fluid. We defined three study groups. In group I (controls), we harvested lungs without hypothermic pulmonary artery flushing, and measured Kfc immediately. In group II (in situ flush), we harvested lungs after hypothermic pulmonary artery flushing with modified Euro-Collins solution, and then measured Kfc. Experiments in groups I and II were designed to evaluate persistent changes in Kfc after pulmonary artery flushing. In group III (ex vivo flush), we flushed lungs ex vivo to evaluate transient changes in Kfc during hypothermic pulmonary artery flushing. Groups I and II did not differ significantly in capillary filtration coefficient and hemodynamics. Group II showed significant alterations on biochemical surfactant analysis and a significant increase in wet-to-dry weight ratio, when compared with group I. In group III, we observed a significant transient increase in capillary filtration coefficient during pulmonary artery flushing. Hypothermic pulmonary artery flushing transiently increases the capillary filtration coefficient, leads to an increase in the wet to dry weight ratio, and induces biochemical surfactant changes. These findings could be explained by the effects of hypothermic modified Euro-Collins solution on pulmonary capillary

  4. Specific heat in diluted magnetic semiconductor quantum ring

    Science.gov (United States)

    Babanlı, A. M.; Ibragimov, B. G.

    2017-11-01

    In the present paper, we have calculated the specific heat and magnetization of a quantum ring of a diluted magnetic semiconductor (DMS) material in the presence of magnetic field. We take into account the effect of Rashba spin-orbital interaction, the exchange interaction and the Zeeman term on the specific heat. We have calculated the energy spectrum of the electrons in diluted magnetic semiconductor quantum ring. Moreover we have calculated the specific heat dependency on the magnetic field and Mn concentration at finite temperature of a diluted magnetic semiconductor quantum ring.

  5. On the Wigner law in dilute random matrices

    Science.gov (United States)

    Khorunzhy, A.; Rodgers, G. J.

    1998-12-01

    We consider ensembles of N × N symmetric matrices whose entries are weakly dependent random variables. We show that random dilution can change the limiting eigenvalue distribution of such matrices. We prove that under general and natural conditions the normalised eigenvalue counting function coincides with the semicircle (Wigner) distribution in the limit N → ∞. This can be explained by the observation that dilution (or more generally, random modulation) eliminates the weak dependence (or correlations) between random matrix entries. It also supports our earlier conjecture that the Wigner distribution is stable to random dilution and modulation.

  6. Dilute Oxygen Combustion Phase IV Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M.F.

    2003-04-30

    Novel furnace designs based on Dilute Oxygen Combustion (DOC) technology were developed under subcontract by Techint Technologies, Coraopolis, PA, to fully exploit the energy and environmental capabilities of DOC technology and to provide a competitive offering for new furnace construction opportunities. Capital cost, fuel, oxygen and utility costs, NOx emissions, oxide scaling performance, and maintenance requirements were compared for five DOC-based designs and three conventional air5-fired designs using a 10-year net present value calculation. A furnace direct completely with DOC burners offers low capital cost, low fuel rate, and minimal NOx emissions. However, these benefits do not offset the cost of oxygen and a full DOC-fired furnace is projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The incremental cost of the improved NOx performance is roughly $6/lb NOx, compared with an estimated $3/lb. NOx for equ8pping a conventional furnace with selective catalytic reduction (SCCR) technology. A furnace fired with DOC burners in the heating zone and ambient temperature (cold) air-fired burners in the soak zone offers low capital cost with less oxygen consumption. However, the improvement in fuel rate is not as great as the full DOC-fired design, and the DOC-cold soak design is also projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The NOx improvement with the DOC-cold soak design is also not as great as the full DOC fired design, and the incremental cost of the improved NOx performance is nearly $9/lb NOx. These results indicate that a DOC-based furnace design will not be generally competitive with conventional technology for new furnace construction under current market conditions. Fuel prices of $7/MMBtu or oxygen prices of $23/ton are needed to make the DOC furnace economics favorable. Niche applications may exist, particularly where access to capital is limited or floor space limitations

  7. Calibration factor or calibration coefficient?

    International Nuclear Information System (INIS)

    Meghzifene, A.; Shortt, K.R.

    2002-01-01

    Full text: The IAEA/WHO network of SSDLs was set up in order to establish links between SSDL members and the international measurement system. At the end of 2001, there were 73 network members in 63 Member States. The SSDL network members provide calibration services to end-users at the national or regional level. The results of the calibrations are summarized in a document called calibration report or calibration certificate. The IAEA has been using the term calibration certificate and will continue using the same terminology. The most important information in a calibration certificate is a list of calibration factors and their related uncertainties that apply to the calibrated instrument for the well-defined irradiation and ambient conditions. The IAEA has recently decided to change the term calibration factor to calibration coefficient, to be fully in line with ISO [ISO 31-0], which recommends the use of the term coefficient when it links two quantities A and B (equation 1) that have different dimensions. The term factor should only be used for k when it is used to link the terms A and B that have the same dimensions A=k.B. However, in a typical calibration, an ion chamber is calibrated in terms of a physical quantity such as air kerma, dose to water, ambient dose equivalent, etc. If the chamber is calibrated together with its electrometer, then the calibration refers to the physical quantity to be measured per electrometer unit reading. In this case, the terms referred have different dimensions. The adoption by the Agency of the term coefficient to express the results of calibrations is consistent with the 'International vocabulary of basic and general terms in metrology' prepared jointly by the BIPM, IEC, ISO, OIML and other organizations. The BIPM has changed from factor to coefficient. The authors believe that this is more than just a matter of semantics and recommend that the SSDL network members adopt this change in terminology. (author)

  8. Extinction Coefficient of Gold Nanostars

    OpenAIRE

    de Puig, Helena; Tam, Justina O.; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly

    2015-01-01

    Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 108 to 26.8 × 108 M−1cm−1. Measured values correl...

  9. Approaches of aroma extraction dilution analysis (AEDA) for headspace solid phase microextraction and gas chromatography-olfactometry (HS-SPME-GC-O): Altering sample amount, diluting the sample or adjusting split ratio?

    Science.gov (United States)

    Feng, Yunzi; Cai, Yu; Sun-Waterhouse, Dongxiao; Cui, Chun; Su, Guowan; Lin, Lianzhu; Zhao, Mouming

    2015-11-15

    Aroma extract dilution analysis (AEDA) is widely used for the screening of aroma-active compounds in gas chromatography-olfactometry (GC-O). In this study, three aroma dilution methods, (I) using different test sample volumes, (II) diluting samples, and (III) adjusting the GC injector split ratio, were compared for the analysis of volatiles by using HS-SPME-AEDA. Results showed that adjusting the GC injector split ratio (III) was the most desirable approach, based on the linearity relationships between Ln (normalised peak area) and Ln (normalised flavour dilution factors). Thereafter this dilution method was applied in the analysis of aroma-active compounds in Japanese soy sauce and 36 key odorants were found in this study. The most intense aroma-active components in Japanese soy sauce were: ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl 4-methylpentanoate, 3-(methylthio)propanal, 1-octen-3-ol, 2-methoxyphenol, 4-ethyl-2-methoxyphenol, 2-methoxy-4-vinylphenol, 2-phenylethanol, and 4-hydroxy-5-ethyl-2-methyl-3(2H)-furanone. Copyright © 2015. Published by Elsevier Ltd.

  10. Form of multicomponent Fickian diffusion coefficients matrix

    International Nuclear Information System (INIS)

    Wambui Mutoru, J.; Firoozabadi, Abbas

    2011-01-01

    Highlights: → Irreversible thermodynamics establishes form of multicomponent diffusion coefficients. → Phenomenological coefficients and thermodynamic factors affect sign of diffusion coefficients. → Negative diagonal elements of diffusion coefficients matrix can occur in non-ideal mixtures. → Eigenvalues of the matrix of Fickian diffusion coefficients may not be all real. - Abstract: The form of multicomponent Fickian diffusion coefficients matrix in thermodynamically stable mixtures is established based on the form of phenomenological coefficients and thermodynamic factors. While phenomenological coefficients form a symmetric positive definite matrix, the determinant of thermodynamic factors matrix is positive. As a result, the Fickian diffusion coefficients matrix has a positive determinant, but its elements - including diagonal elements - can be negative. Comprehensive survey of reported diffusion coefficients data for ternary and quaternary mixtures, confirms that invariably the determinant of the Fickian diffusion coefficients matrix is positive.

  11. A theory of stable-isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Pickup, J.F.; McPherson, C.K.

    1977-01-01

    In order to perform quantitative analysis using stable isotope dilution with mass spectrometry, an equation is derived which describes the relationship between the relative proportions of natural and labelled material and measured isotope ratios

  12. An overview the boron dilution issue in PWRs

    International Nuclear Information System (INIS)

    Hyvaerinen, J.

    1994-01-01

    The presentation is an overview of boron (boric acid) dilution in pressurized water reactors (PWRs). Boric acid has been widely used in PWRs as a dissolved poison, as one of the main reactivity controlling means, for a long time, from nearly but not quite from the beginning of the design, construction and operation of PWRs in the present-day sense. The specific safety issue, namely the risk of uncontrolled reactivity insertion due to inadvertent boron dilution, is discussed first, followed by a brief look on the history of boron usage in PWRs. A discussion of boron dilution phenomenology is presented next in general terms. Some particular concerns that boron dilution phenomena arouse in the minds of a regulator will also be presented before concluding with a brief look on the future of dissolved poisons. (11 refs.)

  13. A Cold Cycle Dilution Refrigerator for Space Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The cold cycle dilution refrigerator is a continuous refrigerator capable of cooling to temperatures below 100 mK that makes use of a novel thermal magnetic pump....

  14. Determination of nanogram amounts of iodide by electrochemical isotope dilution analysis

    International Nuclear Information System (INIS)

    Gabrielsson, A.-B.; Beronius, P.

    1976-01-01

    A known quantity of iodide in ethanol as solvent was labelled with 131 I-and subsequently diluted with a predetermined amount of inactive iodide. Specific activities before and after the isotope dilution were established by anodically depositing small fractions of the halide in each sample on rotating silver micro electrodes and determining the activities of the electrodeposits. The lowest concentration of iodide used in any analysis was 1.10 -5 M. Further deposition studies revealed that iodide can be deposited with 1 100% current efficiency on the rotating silver micro electrode for concentration down to 2.4.10 -6 M. Electrodeposition studies for still lower concentrations have not yet been undertaken. These results suggest that amounts of iodide ion down to about 10 ng, and possibly still smaller quantitites, might be determined with the method developed. Amounts from 42 ng to 1 μg can be determined with an error of 2.5%. (T.G.)

  15. Attentional sets influence perceptual load effects, but not dilution effects.

    Science.gov (United States)

    Benoni, Hanna; Zivony, Alon; Tsal, Yehoshua

    2014-01-01

    Perceptual load theory [Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Performance, 21, 451-468.; Lavie, N., & Tsal, Y. (1994) Perceptual load as a major determinant of the locus of selection in visual attention. Perception & Psychophysics, 56, 183-197.] proposes that interference from distractors can only be avoided in situations of high perceptual load. This theory has been supported by blocked design manipulations separating low load (when the target appears alone) and high load (when the target is embedded among neutral letters). Tsal and Benoni [(2010a). Diluting the burden of load: Perceptual load effects are simply dilution effects. Journal of Experimental Psychology: Human Perception and Performance, 36, 1645-1656.; Benoni, H., & Tsal, Y. (2010). Where have we gone wrong? Perceptual load does not affect selective attention. Vision Research, 50, 1292-1298.] have recently shown that these manipulations confound perceptual load with "dilution" (the mere presence of additional heterogeneous items in high-load situations). Theeuwes, Kramer, and Belopolsky [(2004). Attentional set interacts with perceptual load in visual search. Psychonomic Bulletin & Review, 11, 697-702.] independently questioned load theory by suggesting that attentional sets might also affect distractor interference. When high load and low load were intermixed, and participants could not prepare for the presentation that followed, both the low-load and high-load trials showed distractor interference. This result may also challenge the dilution account, which proposes a stimulus-driven mechanism. In the current study, we presented subjects with both fixed and mixed blocks, including a mix of dilution trials with low-load trials and with high-load trials. We thus separated the effect of dilution from load and tested the influence of attentional sets on each component. The results revealed that whereas

  16. Accurate determination and certification of bromine in plastic by isotope dilution inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ohata, Masaki, E-mail: m-oohata@aist.go.jp; Miura, Tsutomu

    2014-07-21

    Highlights: • Accurate analytical method of Br in plastic was studied by isotope dilution ICPMS. • A microwave acid digestion using quartz vessel was suitable for Br analysis. • Sample dilution by NH{sub 3} solution could remove memory effect for ICPMS measurement. • The analytical result of the ID-ICPMS showed consistency with that of INAA. • The ID-ICPMS developed could apply to certification of Br in candidate plastic CRM. - Abstract: The accurate analytical method of bromine (Br) in plastic was developed by an isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The figures of merit of microwave acid digestion procedures using polytetrafluoroethylene (PTFE) or quartz vessels were studied and the latter one was suitable for Br analysis since its material was free from Br contamination. The sample dilution procedures using Milli-Q water or ammonium (NH{sub 3}) solution were also studied to remove memory effect for ICPMS measurement. Although severe memory effect was observed on Milli-Q water dilution, NH{sub 3} solution could remove it successfully. The accuracy of the ID-ICPMS was validated by a certified reference material (CRM) as well as the comparison with the analytical result obtained by an instrumental neutron activation analysis (INAA) as different analytical method. From these results, the ID-ICPMS developed in the present study could be evaluated as accurate analytical method of Br in plastic materials and it could apply to certification of Br in candidate plastic CRM with respect to such regulations related to RoHS (restriction of the use of hazardous substances in electrical and electronics equipment) directive.

  17. Accurate determination and certification of bromine in plastic by isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Ohata, Masaki; Miura, Tsutomu

    2014-01-01

    Highlights: • Accurate analytical method of Br in plastic was studied by isotope dilution ICPMS. • A microwave acid digestion using quartz vessel was suitable for Br analysis. • Sample dilution by NH 3 solution could remove memory effect for ICPMS measurement. • The analytical result of the ID-ICPMS showed consistency with that of INAA. • The ID-ICPMS developed could apply to certification of Br in candidate plastic CRM. - Abstract: The accurate analytical method of bromine (Br) in plastic was developed by an isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The figures of merit of microwave acid digestion procedures using polytetrafluoroethylene (PTFE) or quartz vessels were studied and the latter one was suitable for Br analysis since its material was free from Br contamination. The sample dilution procedures using Milli-Q water or ammonium (NH 3 ) solution were also studied to remove memory effect for ICPMS measurement. Although severe memory effect was observed on Milli-Q water dilution, NH 3 solution could remove it successfully. The accuracy of the ID-ICPMS was validated by a certified reference material (CRM) as well as the comparison with the analytical result obtained by an instrumental neutron activation analysis (INAA) as different analytical method. From these results, the ID-ICPMS developed in the present study could be evaluated as accurate analytical method of Br in plastic materials and it could apply to certification of Br in candidate plastic CRM with respect to such regulations related to RoHS (restriction of the use of hazardous substances in electrical and electronics equipment) directive

  18. Regional water coefficients for U.S. industrial sectors

    Directory of Open Access Journals (Sweden)

    Riccardo Boero

    2017-12-01

    Full Text Available Designing policies for water systems management requires the capability to assess the economic impacts of water availability and to effectively couple water withdrawals by human activities with natural hydrologic dynamics. At the core of any scientific approach to these issues there is the estimation of water withdrawals by industrial sectors in the form of water coefficients, which are measurements of the quantity of water withdrawn per dollar of GDP or output. In this work we focus on the contiguous United States and on the estimation of water coefficients for regional scale analyses. We first compare an established methodology for the estimation of national water coefficients with a parametric one we propose. Second, we introduce a method to estimate water coefficients at the level of ecological regions and we discuss how they reduce possible biases in regional analyses of water systems. We conclude discussing advantages and limits of regional water coefficients.

  19. Effects of dissolved species on radiolysis of diluted seawater

    International Nuclear Information System (INIS)

    Hata, Kuniki; Hanawa, Satoshi; Kasahara, Shigeki; Motooka, Takafumi; Tsukada, Takashi; Muroya, Yusa; Yamashita, Shinichi; Katsumura, Yosuke

    2014-01-01

    Fukushima Daiichi Nuclear Power Plants (NPPs) experienced seawater injection into the cores and fuel pools as an emergent measure after the accident. After the accident, retained water has been continuously desalinized, and subsequently the concentration of chloride ion (Cl"-) has been kept at a lower level these days. These ions in seawater are known to affect water radiolysis, which causes the production of radiolytic products, such as hydrogen peroxide (H_2O_2), molecular hydrogen (H_2) and molecular oxygen (O_2). However, the effects of dissolved ions relating seawater on the production of the stable radiolytic products are not well understood in the diluted seawater. To understand of the production behavior in diluted seawater under radiation, radiolysis calculations were carried out. Production of H_2 is effectively suppressed by diluting by up to vol10%. The concentrations of oxidants (H_2O_2 and O_2) are also suppressed by dilution of dissolved species. The effect of oxidants on corrosion of materials is thought to be low when the seawater was diluted by less than 1 vol% by water. It is also shown that deaeration is one of the effective measure to suppress the concentrations of oxidants at a lower level for any dilution conditions. (author)

  20. Dilution Refrigeration of Multi-Ton Cold Masses

    CERN Document Server

    Wikus, P; CERN. Geneva

    2007-01-01

    Dilution refrigeration is the only means to provide continuous cooling at temperatures below 250 mK. Future experiments featuring multi-ton cold masses require a new generation of dilution refrigeration systems, capable of providing a heat sink below 10 mK at cooling powers which exceed the performance of present systems considerably. This thesis presents some advances towards dilution refrigeration of multi-ton masses in this temperature range. A new method using numerical simulation to predict the cooling power of a dilution refrigerator of a given design has been developed in the framework of this thesis project. This method does not only allow to take into account the differences between an actual and an ideal continuous heat exchanger, but also to quantify the impact of an additional heat load on an intermediate section of the dilute stream. In addition, transient behavior can be simulated. The numerical model has been experimentally verified with a dilution refrigeration system which has been designed, ...

  1. Study of transport coefficients of nanodiamond nanofluids

    Science.gov (United States)

    Pryazhnikov, M. I.; Minakov, A. V.; Guzei, D. V.

    2017-09-01

    Experimental data on the thermal conductivity coefficient and viscosity coefficient of nanodiamond nanofluids are presented. Distilled water and ethylene glycol were used as the base fluid. Dependences of transport coefficients on concentration are obtained. It was shown that the thermal conductivity coefficient increases with increasing nanodiamonds concentration. It was shown that base fluids properties and nanodiamonds concentration affect on the rheology of nanofluids.

  2. Evolution of Sr distribution coefficient as a function of time, incubation conditions and measurement technique

    International Nuclear Information System (INIS)

    Wang Guo; Staunton, Siobhan

    2005-01-01

    A thorough understanding of the dynamics of radiostrontium in soil is required to allow accurate long-term predictions of its mobility. We have followed the soil solution distribution of 85 Sr as a function of time under controlled conditions over 4 months and studied the effect of soil moisture content and organic matter amendments. Data have been compared to redox conditions and soil pH. To fuel the ongoing debate on the validity of distribution coefficient (K d ) values measured in dilute suspension, we have compared values obtained from the activity concentration in soil solution obtained by centrifugation to data obtained in suspension with or without air-drying of the soil samples after incubation. The 85 Sr adsorption properties of soil, incubated without prior contamination were also measured. There is some time-dependent adsorption of Sr. This is partly due to changing soil composition due to the decomposition of added organic matter and anaerobic conditions induced by flooding. There is also a kinetic effect, but adsorption remains largely reversible. Most of the observed effects are lost when soil is suspended in electrolyte solution

  3. Dermal absorption of a dilute aqueous solution of malathion

    Directory of Open Access Journals (Sweden)

    Scharf John

    2008-01-01

    Full Text Available Malathion is an organophosphate pesticide commonly used on field crops, fruit trees, livestock, agriculture, and for mosquito and medfly control. Aerial applications can result in solubilized malathion in swimming pools and other recreational waters that may come into contact with human skin. To evaluate the human skin absorption of malathion for the assessment of risk associated with human exposures to aqueous solutions, human volunteers were selected and exposed to aqueous solutions of malathion. Participants submerged their arms and hands in twenty liters of dilute malathion solution in either a stagnant or stirred state. The "disappearance method" was applied by measuring malathion concentrations in the water before and after human exposure for various periods of time. No measurable skin absorption was detected in 42% of the participants; the remaining 58% of participants measured minimal absorbed doses of malathion. Analyzing these results through the Hazard Index model for recreational swimmer and bather exposure levels typically measured in contaminated swimming pools and surface waters after bait application indicated that these exposures are an order of magnitude less than a minimal dose known to result in a measurable change in acetylcholinesterase activity. It is concluded that exposure to aqueous malathion in recreational waters following aerial bait applications is not appreciably absorbed, does not result in an effective dose, and therefore is not a public health hazard.

  4. Spectrophotometric-isotope dilution determination of arsenic in soils and rock

    Science.gov (United States)

    Brown, F.W.; Simon, F.O.; Greenland, L.P.

    1975-01-01

    Arsenic in soil and rock samples may be determined in part-per-million concentrations using a radiochemical-isotope dilution method. Arsenic in the sample plus added As76 tracer is separated as arsine and determined spectrophotometrically as a molybdenum blue complex. The As76 activity in the absorbing solution allows corrections for chemical losses. A lower limit of 1 ppm is determinate in a 0.5-g sample.

  5. Evaluation of Rock Joint Coefficients

    Science.gov (United States)

    Audy, Ondřej; Ficker, Tomáš

    2017-10-01

    A computer method for evaluation of rock joint coefficients is described and several applications are presented. The method is based on two absolute numerical indicators that are formed by means of the Fourier replicas of rock joint profiles. The first indicator quantifies the vertical depth of profiles and the second indicator classifies wavy character of profiles. The absolute indicators have replaced the formerly used relative indicators that showed some artificial behavior in some cases. This contribution is focused on practical computations testing the functionality of the newly introduced indicators.

  6. Correlation coefficients in neutron β-decay

    International Nuclear Information System (INIS)

    Byrne, J.

    1978-01-01

    The various angular and polarisation coefficients in neutron decay are the principal sources of information on the β-interaction. Measurements of the electron-neutrino angular correlation coefficient (a), the neutron-spin-electron-momentum correlation coefficient (A), the neutron-spin-neutrino-momentum correlation coefficient (B), and the triple correlation coefficient D and time-reversal invariance are reviewed and the results discussed. (U.K.)

  7. Modeling syngas-fired gas turbine engines with two dilutants

    Science.gov (United States)

    Hawk, Mitchell E.

    2011-12-01

    Prior gas turbine engine modeling work at the University of Wyoming studied cycle performance and turbine design with air and CO2-diluted GTE cycles fired with methane and syngas fuels. Two of the cycles examined were unconventional and innovative. The work presented herein reexamines prior results and expands the modeling by including the impacts of turbine cooling and CO2 sequestration on GTE cycle performance. The simple, conventional regeneration and two alternative regeneration cycle configurations were examined. In contrast to air dilution, CO2 -diluted cycle efficiencies increased by approximately 1.0 percentage point for the three regeneration configurations examined, while the efficiency of the CO2-diluted simple cycle decreased by approximately 5.0 percentage points. For CO2-diluted cycles with a closed-exhaust recycling path, an optimum CO2-recycle pressure was determined for each configuration that was significantly lower than atmospheric pressure. Un-cooled alternative regeneration configurations with CO2 recycling achieved efficiencies near 50%, which was approximately 3.0 percentage points higher than the conventional regeneration cycle and simple cycle configurations that utilized CO2 recycling. Accounting for cooling of the first two turbine stages resulted in a 2--3 percentage point reduction in un-cooled efficiency, with air dilution corresponding to the upper extreme. Additionally, when the work required to sequester CO2 was accounted for, cooled cycle efficiency decreased by 4--6 percentage points, and was more negatively impacted when syngas fuels were used. Finally, turbine design models showed that turbine blades are shorter with CO2 dilution, resulting in fewer design restrictions.

  8. Dilution Ratios for HB Line Phase I Eductor System

    International Nuclear Information System (INIS)

    Steimke, J.L.

    2002-01-01

    HB Line Phase I product transfer includes an eductor which transfers liquid from Product Hold Tank (PHT) RT-33 or RT-34 to Tank 11.1. The eductor also dilutes the liquid from the PHT with eductant. Dilution must be reliably controlled because of criticality concerns with H Canyon Tanks. The eductor system, which contains a 1 inch Model 264 Schutte and Koerting eductor, was previously modeled [1] in 1998 and dilution ratios were calculated for different flow restrictors, eductant pressures and densities for the eductant and the contents of the PHT. The previous calculation was performed using spreadsheet software no longer supported at SRS. For the previous work dilution ratio was defined as the volume of eductant consumed divided by volume of PHT contents transferred. Since 1998 HB Line Engineering has changed the definition of dilution ratio to the total volume of liquid, eductant consumed plus the volume of PHT liquid transferred, divided by the volume of PHT liquid transferred. The 1998 base case calculation was for a restrictor diameter of 0.334 inches, an eductant supply pressure of 15 psig, full PHT, an eductant specific gravity of 1.385 and a PHT density of 1.015. The base case dilution ratio calculated in 1998 using the current definition was 3.52. After accounting for uncertainty the minimum dilution ratio decreased to 3.23. In 2001 HB Line Engineering requested that the calculation be repeated for a manganous nitrate solution eductant and also a process water eductant. The other conditions were the same as for the 1998 calculation. The objective of this report is to document the calculations and the results

  9. Diffusion of dilute gas in arrays of randomly distributed, vertically aligned, high-aspect-ratio cylinders

    Directory of Open Access Journals (Sweden)

    Wojciech Szmyt

    2017-01-01

    Full Text Available In this work we modelled the diffusive transport of a dilute gas along arrays of randomly distributed, vertically aligned nanocylinders (nanotubes or nanowires as opposed to gas diffusion in long pores, which is described by the well-known Knudsen theory. Analytical expressions for (i the gas diffusion coefficient inside such arrays, (ii the time between collisions of molecules with the nanocylinder walls (mean time of flight, (iii the surface impingement rate, and (iv the Knudsen number of such a system were rigidly derived based on a random-walk model of a molecule that undergoes memoryless, diffusive reflections from nanocylinder walls assuming the molecular regime of gas transport. It can be specifically shown that the gas diffusion coefficient inside such arrays is inversely proportional to the areal density of cylinders and their mean diameter. An example calculation of a diffusion coefficient is delivered for a system of titanium isopropoxide molecules diffusing between vertically aligned carbon nanotubes. Our findings are important for the correct modelling and optimisation of gas-based deposition techniques, such as atomic layer deposition or chemical vapour deposition, frequently used for surface functionalisation of high-aspect-ratio nanocylinder arrays in solar cells and energy storage applications. Furthermore, gas sensing devices with high-aspect-ratio nanocylinder arrays and the growth of vertically aligned carbon nanotubes need the fundamental understanding and precise modelling of gas transport to optimise such processes.

  10. Interactions between Zygosaccharomyces mellis and Wallemia sebi in diluted molasses.

    Science.gov (United States)

    Vindeløv, J; Arneborg, N

    2001-01-22

    The yeast Zygosaccharomyces mellis and the mould Wallemia sebi were isolated from the same sample of crystalline sugar. Interactions between these fungi were investigated using a diluted molasses medium (water activity 0.89, pH 6.0) as a model system for the syrup film covering the surface of moist crystalline sugar. Single and mixed cultures of Z. mellis and W. sebi were incubated at 25 degrees C for 400 h. Our results show that the growth of Z. mellis in single culture was limited by available glucose and fructose, and that W sebi was able to invert sucrose to glucose and fructose in both single and mixed culture. Furthermore, the presence of W. sebi in the mixed culture increased the maximum specific growth rate of Z. mellis from 0.074 to 0.19 h(-1) and the growth yield of Z. mellis from 7.3 x 10(6) to 5.4 x 10(7) cfu/ml. These results indicate that the ability of W. sebi to invert sucrose may stimulate the growth of Z. mellis. Finally, the presence of Z. mellis inhibited the ability of W. sebi to invert sucrose: W. sebi was able to invert 1.0 g sucrose/l per h in single culture but only 0.6 g sucrose/l per h in mixed culture. As predicted by Raoults law, this corresponded to a reduction in the water activity of the growth medium from 0.890 to 0.850 in single culture, and to 0.865 in mixed culture.

  11. Extinction Coefficient of Gold Nanostars.

    Science.gov (United States)

    de Puig, Helena; Tam, Justina O; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly

    2015-07-30

    Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 10 8 to 26.8 × 10 8 M -1 cm -1 . Measured values correlate with those obtained from theoretical models of the NStars using the discrete dipole approximation (DDA), which we use to simulate the extinction spectra of the nanostars. Finally, because NStars are typically used in biological applications, we conjugate DNA and antibodies to the NStars and calculate the footprint of the bound biomolecules.

  12. Kerr scattering coefficients via isomonodromy

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Bruno Carneiro da [Departamento de Física, Universidade Federal de Pernambuco,50670-901, Recife, Pernambuco (Brazil); Novaes, Fábio [International Institute of Physics, Federal University of Rio Grande do Norte,Av. Odilon Gomes de Lima 1722, Capim Macio, Natal-RN 59078-400 (Brazil)

    2015-11-23

    We study the scattering of a massless scalar field in a generic Kerr background. Using a particular gauge choice based on the current conservation of the radial equation, we give a generic formula for the scattering coefficient in terms of the composite monodromy parameter σ between the inner and the outer horizons. Using the isomonodromy flow, we calculate σ exactly in terms of the Painlevé V τ-function. We also show that the eigenvalue problem for the angular equation (spheroidal harmonics) can be calculated using the same techniques. We use recent developments relating the Painlevé V τ-function to Liouville irregular conformal blocks to claim that this scattering problem is solved in the combinatorial sense, with known expressions for the τ-function near the critical points.

  13. Cytotoxic effects of ultra-diluted remedies on breast cancer cells.

    Science.gov (United States)

    Frenkel, Moshe; Mishra, Bal Mukund; Sen, Subrata; Yang, Peiying; Pawlus, Alison; Vence, Luis; Leblanc, Aimee; Cohen, Lorenzo; Banerji, Pratip; Banerji, Prasanta

    2010-02-01

    The use of ultra-diluted natural products in the management of disease and treatment of cancer has generated a lot of interest and controversy. We conducted an in vitro study to determine if products prescribed by a clinic in India have any effect on breast cancer cell lines. We studied four ultra-diluted remedies (Carcinosin, Phytolacca, Conium and Thuja) against two human breast adenocarcinoma cell lines (MCF-7 and MDA-MB-231) and a cell line derived from immortalized normal human mammary epithelial cells (HMLE). The remedies exerted preferential cytotoxic effects against the two breast cancer cell lines, causing cell cycle delay/arrest and apoptosis. These effects were accompanied by altered expression of the cell cycle regulatory proteins, including downregulation of phosphorylated Rb and upregulation of the CDK inhibitor p27, which were likely responsible for the cell cycle delay/arrest as well as induction of the apoptotic cascade that manifested in the activation of caspase 7 and cleavage of PARP in the treated cells. The findings demonstrate biological activity of these natural products when presented at ultra-diluted doses. Further in-depth studies with additional cell lines and animal models are warranted to explore the clinical applicability of these agents.

  14. The interlaboratory experiment IDA-72 on mass spectrometric isotope dilution analysis. Vol. 1

    International Nuclear Information System (INIS)

    Beyrich, W.; Drosselmeyer, E.

    1975-07-01

    Within the framework of the Safeguards Project of the Federal Republic of Germany at the Nuclear Research Center Karlsruhe an analytical intercomparison program was carried out in cooperation with 22 laboratories of 13 countries or international organizations. The main objective was the acquisition of basic data on the errors involved in the mass spectrometric isotope dilution analysis if it is applied to the determination of uranium and plutonium in diluted active feed solutions of reprocessing plants in routine operation. The results were evaluated by statistical methods mainly in regard to the calculation of the estimates of the variances for the different error components contributing to the total error of this analytical technique. Furthermore, the performance of two new methods for sample conditioning suggested by the International Atomic Energy Agency, Vienna, and the European Institute for Transuranium Elements (EURATOM), Karlsruhe, was successfully tested. The results of some investigations on the stability of diluted high active feed solutions and on comparison analysis by X-ray fluorescence spectrometry are also included. Data on the analytical efforts (manhours) invested in this study are reported as well as general experiences made in the organization and performance of an experiment on such an extended international level. (orig.) [de

  15. Reverse isotope dilution method for determining benzene and metabolites in tissues

    International Nuclear Information System (INIS)

    Bechtold, W.E.; Sabourin, P.J.; Henderson, R.F.

    1988-01-01

    A method utilizing reverse isotope dilution for the analysis of benzene and its organic soluble metabolites in tissues of rats and mice is presented. Tissues from rats and mice that had been exposed to radiolabeled benzene were extracted with ethyl acetate containing known, excess quantities of unlabeled benzene and metabolites. Butylated hydroxytoluene was added as an antioxidant. The ethyl acetate extracts were analyzed with semipreparative reversed-phase HPLC. Isolated peaks were collected and analyzed for radioactivity (by liquid scintillation spectrometry) and for mass (by UV absorption). The total amount of each compound present was calculated from the mass dilution of the radiolabeled isotope. This method has the advantages of high sensitivity, because of the high specific activity of benzene, and relative stability of the analyses, because of the addition of large amounts of unlabeled carrier analogue

  16. Coefficients of productivity for Yellowstone's grizzly bear habitat

    Science.gov (United States)

    Mattson, David John; Barber, Kim; Maw, Ralene; Renkin, Roy

    2004-01-01

    This report describes methods for calculating coefficients used to depict habitat productivity for grizzly bears in the Yellowstone ecosystem. Calculations based on these coefficients are used in the Yellowstone Grizzly Bear Cumulative Effects Model to map the distribution of habitat productivity and account for the impacts of human facilities. The coefficients of habitat productivity incorporate detailed information that was collected over a 20-year period (1977-96) on the foraging behavior of Yellowstone's bears and include records of what bears were feeding on, when and where they fed, the extent of that feeding activity, and relative measures of the quantity consumed. The coefficients also incorporate information, collected primarily from 1986 to 1992, on the nutrient content of foods that were consumed, their digestibility, characteristic bite sizes, and the energy required to extract and handle each food. Coefficients were calculated for different time periods and different habitat types, specific to different parts of the Yellowstone ecosystem. Stratifications included four seasons of bear activity (spring, estrus, early hyperphagia, late hyperphagia), years when ungulate carrion and whitebark pine seed crops were abundant versus not, areas adjacent to (bear activity in each region, habitat type, and time period were incorporated into calculations, controlling for the effects of proximity to human facilities. The coefficients described in this report and associated estimates of grizzly bear habitat productivity are unique among many efforts to model the conditions of bear habitat because calculations include information on energetics derived from the observed behavior of radio-marked bears.

  17. Mobile Melt-Dilute Treatment for Russian Spent Nuclear Fuel

    International Nuclear Information System (INIS)

    Peacock, H.

    2002-01-01

    Treatment of spent Russian fuel using a Melt-Dilute (MD) process is proposed to consolidate fuel assemblies into a form that is proliferation resistant and provides critically safety under storage and disposal configurations. Russian fuel elements contain a variety of fuel meat and cladding materials. The Melt-Dilute treatment process was initially developed for aluminum-based fuels so additional development is needed for several cladding and fuel meat combinations in the Russian fuel inventory (e.g. zirconium-clad, uranium-zirconium alloy fuel). A Mobile Melt-Dilute facility (MMD) is being proposed for treatment of spent fuels at reactor site storage locations in Russia; thereby, avoiding the costs of building separate treatment facilities at each site and avoiding shipment of enriched fuel assemblies over the road. The MMD facility concept is based on laboratory tests conducted at the Savannah River Technology Center (SRTC), and modular pilot-scale facilities constructed at the Savannah River Site for treatment of US spent fuel. SRTC laboratory tests have shown the feasibility of operating a Melt-Dilute treatment process with either a closed system or a filtered off-gas system. The proposed Mobile Melt-Dilute process is presented in this paper

  18. Quantifying the dilution effect for models in ecological epidemiology.

    Science.gov (United States)

    Roberts, M G; Heesterbeek, J A P

    2018-03-01

    The dilution effect , where an increase in biodiversity results in a reduction in the prevalence of an infectious disease, has been the subject of speculation and controversy. Conversely, an amplification effect occurs when increased biodiversity is related to an increase in prevalence. We explore the conditions under which these effects arise, using multi species compartmental models that integrate ecological and epidemiological interactions. We introduce three potential metrics for quantifying dilution and amplification, one based on infection prevalence in a focal host species, one based on the size of the infected subpopulation of that species and one based on the basic reproduction number. We introduce our approach in the simplest epidemiological setting with two species, and show that the existence and strength of a dilution effect is influenced strongly by the choices made to describe the system and the metric used to gauge the effect. We show that our method can be generalized to any number of species and to more complicated ecological and epidemiological dynamics. Our method allows a rigorous analysis of ecological systems where dilution effects have been postulated, and contributes to future progress in understanding the phenomenon of dilution in the context of infectious disease dynamics and infection risk. © 2018 The Author(s).

  19. Initial magnetic susceptibility of the diluted magnetopolymer elastic composites

    International Nuclear Information System (INIS)

    Borin, D.Yu.; Odenbach, S.

    2017-01-01

    In this work diluted magnetopolymer elastic composites based on magnetic microparticles are experimentally studied. Considered samples have varied concentration of the magnetic powder and different structural anisotropy. Experimental data on magnetic properties are accomplished by microstructural observations performed using X-Ray tomography. Influence of the particles amount and structuring effects on the initial magnetic susceptibility of the composites as well as the applicability of the Maxwell-Garnett approximation, which is widely used in considerations of magnetopolymer elastic composites, are evaluated. It is demonstrated that the approximation works well for diluted samples containing randomly distributed magnetic particles and for the diluted samples with chain-like structures oriented perpendicular to an externally applied field, while it fails to predict the susceptibility of the samples with structures oriented parallel to the field. Moreover, it is shown, that variation of the chains morphology does not significantly change the composite initial magnetic susceptibility. - Highlights: • The Maxwell-Garnet prediction works well for the diluted isotropic composites. • The Maxwell-Garnet prediction can be used for composites with structures oriented perpendicular to an applied field. • Chains oriented parallel to an applied field significantly increase the composite initial magnetic susceptibility. • The number and thickness of chains is not of the highest importance for the diluted composites. • The crucial reason of the observed effect is expected to be the demagnetisation factor of the chains.

  20. A probabilistic analysis of rapid boron dilution scenarios

    International Nuclear Information System (INIS)

    Kohut, P.; Diamond, D.J.

    1993-01-01

    A probabilistic and deterministic analysis of a rapid boron dilution scenario related to reactor restart was performed. The event is initiated by a loss of off-site power during the startup dilution process. The automatic restart of the charging pump in such cases may lead to the accumulation of a diluted slug of water in the lower plenum. The restart of the reactor coolant pumps may send the diluted slug through the core, adding sufficient reactivity to overcome the shutdown margin and cause a power excursion. The concern is that the power excursion is sufficient in certain circumstances to cause fuel damage. The estimated core damage frequency based on the scoping analysis is 1.0--3.0E-05/yr for the plants analyzed. These are relatively significant values when compared to desirable goals. The analysis contained assumptions related to plant specific design characteristics which may lead to non-conservative estimates. The most important conservative assumptions were that mixing of the injected diluted water is insignificant and that fuel damage occurs when the slug passes through the core

  1. Quantification of fentanyl in serum by isotope dilution analysis using capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Sera, Shoji; Goromaru, Tsuyoshi [Fukuyama Univ., Hiroshima (Japan); Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

    1998-06-01

    The quantitative determination of fentanyl (FT) in serum was examined by isotope dilution analysis using a capillary gas chromatograph equipped with a surface ionization detector. The separation of FT and its deuterated analogue, FT-{sup 2}H{sub 19}, was achieved within 15 min a column temperature of 260degC by using a 25 m column. Measurement of the samples prepared by the addition of a known amount of FT in the range of 0.2 to 40 ng/ml with 20 ng/ml of FT-{sup 2}H{sub 19} to human control serum allowed observation of a linear relationship between the peak area ratio and the added amount ratio. The correlation coefficient obtained by regression analysis was 0.999. The advantage of the present isotope dilution method was demonstrated by comparison with other FT analogues which substituted a propionyl group with an acetyl group or a phenethyl group with a benzyl group as the internal standard. The present method was used to determine the serum level of FT in surgical patients after i.v. administration. No endogenous compounds and concomitant drugs interfered with the detection of FT or FT-{sup 2}H{sub 19}. This method was considered to be useful for the pharmacokinetic study of FT in patients. (author)

  2. Perpendicular diffusion of a dilute beam of charged particles in the PK-4 dusty plasma

    Science.gov (United States)

    Liu, Bin; Goree, John

    2015-09-01

    We study the random walk of a dilute beam of projectile dust particles that drift through a target dusty plasma. This random walk is a diffusion that occurs mainly due to Coulomb collisions with target particles that have a different size. In the direction parallel to the drift, projectiles exhibit mobility-limited motion with a constant average velocity. We use a 3D molecular dynamics (MD) simulation of the dust particle motion to determine the diffusion and mobility coefficients for the dilute beam. The dust particles are assumed to interact with a shielded Coulomb repulsion. They also experience gas drag. The beam particles are driven by a prescribed net force that is not applied to the target particles; in the experiments this net force is due to an imbalance of the electric and ion drag forces. This simulation is motivated by microgravity experiments, with the expectation that the scattering of projectiles studied here will be observed in upcoming PK-4 experiments on the International Space Station. Supported by NASA and DOE.

  3. Numerical simulation of solute trapping phenomena using phase-field solidification model for dilute binary alloys

    Directory of Open Access Journals (Sweden)

    Henrique Silva Furtado

    2009-09-01

    Full Text Available Numerical simulation of solute trapping during solidification, using two phase-field model for dilute binary alloys developed by Kim et al. [Phys. Rev. E, 60, 7186 (1999] and Ramirez et al. [Phys. Rev. E, 69, 05167 (2004] is presented here. The simulations on dilute Cu-Ni alloy are in good agreement with one dimensional analytic solution of sharp interface model. Simulation conducted under small solidification velocity using solid-liquid interface thickness (2λ of 8 nanometers reproduced the solute (Cu equilibrium partition coefficient. The spurious numerical solute trapping in solid phase, due to the interface thickness was negligible. A parameter used in analytical solute trapping model was determined by isothermal phase-field simulation of Ni-Cu alloy. Its application to Si-As and Si-Bi alloys reproduced results that agree reasonably well with experimental data. A comparison between the three models of solute trapping (Aziz, Sobolev and Galenko [Phys. Rev. E, 76, 031606 (2007] was performed. It resulted in large differences in predicting the solidification velocity for partition-less solidification, indicating the necessity for new and more acute experimental data.

  4. Quantification of fentanyl in serum by isotope dilution analysis using capillary gas chromatography

    International Nuclear Information System (INIS)

    Sera, Shoji; Goromaru, Tsuyoshi; Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

    1998-01-01

    The quantitative determination of fentanyl (FT) in serum was examined by isotope dilution analysis using a capillary gas chromatograph equipped with a surface ionization detector. The separation of FT and its deuterated analogue, FT- 2 H 19 , was achieved within 15 min a column temperature of 260degC by using a 25 m column. Measurement of the samples prepared by the addition of a known amount of FT in the range of 0.2 to 40 ng/ml with 20 ng/ml of FT- 2 H 19 to human control serum allowed observation of a linear relationship between the peak area ratio and the added amount ratio. The correlation coefficient obtained by regression analysis was 0.999. The advantage of the present isotope dilution method was demonstrated by comparison with other FT analogues which substituted a propionyl group with an acetyl group or a phenethyl group with a benzyl group as the internal standard. The present method was used to determine the serum level of FT in surgical patients after i.v. administration. No endogenous compounds and concomitant drugs interfered with the detection of FT or FT- 2 H 19 . This method was considered to be useful for the pharmacokinetic study of FT in patients. (author)

  5. Transverse gradient diffusion in a polydisperse dilute suspension of magnetic spheres during sedimentation

    International Nuclear Information System (INIS)

    Cunha, F R; Couto, H L G

    2008-01-01

    In this work we investigate the pair interaction of magnetic particles in a dilute polydisperse sedimenting suspension. The suspension is composed of magnetic spherical forms of different radii and densities immersed in a Newtonian fluid, settling due to the gravity. When in close contact, the particles may exert on each other a magnetic force due to a permanent magnetization. We restrict our attention to dispersions of micromagnetic composite with negligible Brownian motion. The calculations of the relative particle trajectories are based on direct computations of the hydrodynamic interactions among rigid spheres in the regime of low particle Reynolds number. Depending on the relative importance of the interparticle forces and gravity, the collisions may result in aggregation or simply in a breaking of the particle relative trajectory time reversibility. After summing over all possible encounters, the transverse self-diffusion and down-gradient diffusion coefficients that describe the cross-flow migration of the particles are calculated. Our calculation shows first evidence and the significance of the diffusion process arising from magnetic interactions in dilute non-Brownian suspensions

  6. Transverse gradient diffusion in a polydisperse dilute suspension of magnetic spheres during sedimentation

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, F R; Couto, H L G [Departamento de Engenharia Mecanica, Universidade de Brasilia, Faculdade de Tecnologia, Grupo de Mecanica dos Fluidos de Escoamentos Complexos-VORTEX, Campus Universitario Darcy Ribeiro, 70910-900, Brasilia, DF (Brazil)], E-mail: frcunha@unb.br

    2008-05-21

    In this work we investigate the pair interaction of magnetic particles in a dilute polydisperse sedimenting suspension. The suspension is composed of magnetic spherical forms of different radii and densities immersed in a Newtonian fluid, settling due to the gravity. When in close contact, the particles may exert on each other a magnetic force due to a permanent magnetization. We restrict our attention to dispersions of micromagnetic composite with negligible Brownian motion. The calculations of the relative particle trajectories are based on direct computations of the hydrodynamic interactions among rigid spheres in the regime of low particle Reynolds number. Depending on the relative importance of the interparticle forces and gravity, the collisions may result in aggregation or simply in a breaking of the particle relative trajectory time reversibility. After summing over all possible encounters, the transverse self-diffusion and down-gradient diffusion coefficients that describe the cross-flow migration of the particles are calculated. Our calculation shows first evidence and the significance of the diffusion process arising from magnetic interactions in dilute non-Brownian suspensions.

  7. Non‐diluted seawater enhances nasal ciliary beat frequency and wound repair speed compared to diluted seawater and normal saline

    Science.gov (United States)

    Bonnomet, Arnaud; Luczka, Emilie; Coraux, Christelle

    2016-01-01

    Background The regulation of mucociliary clearance is a key part of the defense mechanisms developed by the airway epithelium. If a high aggregate quality of evidence shows the clinical effectiveness of nasal irrigation, there is a lack of studies showing the intrinsic role of the different irrigation solutions allowing such results. This study investigated the impact of solutions with different pH and ionic compositions, eg, normal saline, non‐diluted seawater and diluted seawater, on nasal mucosa functional parameters. Methods For this randomized, controlled, blinded, in vitro study, we used airway epithelial cells obtained from 13 nasal polyps explants to measure ciliary beat frequency (CBF) and epithelial wound repair speed (WRS) in response to 3 isotonic nasal irrigation solutions: (1) normal saline 0.9%; (2) non‐diluted seawater (Physiomer®); and (3) 30% diluted seawater (Stérimar). The results were compared to control (cell culture medium). Results Non‐diluted seawater enhanced the CBF and the WRS when compared to diluted seawater and to normal saline. When compared to the control, it significantly enhanced CBF and slightly, though nonsignificantly, improved the WRS. Interestingly, normal saline markedly reduced the number of epithelial cells and ciliated cells when compared to the control condition. Conclusion Our results suggest that the physicochemical features of the nasal wash solution is important because it determines the optimal conditions to enhance CBF and epithelial WRS thus preserving the respiratory mucosa in pathological conditions. Non‐diluted seawater obtains the best results on CBF and WRS vs normal saline showing a deleterious effect on epithelial cell function. PMID:27101776

  8. Non-diluted seawater enhances nasal ciliary beat frequency and wound repair speed compared to diluted seawater and normal saline.

    Science.gov (United States)

    Bonnomet, Arnaud; Luczka, Emilie; Coraux, Christelle; de Gabory, Ludovic

    2016-10-01

    The regulation of mucociliary clearance is a key part of the defense mechanisms developed by the airway epithelium. If a high aggregate quality of evidence shows the clinical effectiveness of nasal irrigation, there is a lack of studies showing the intrinsic role of the different irrigation solutions allowing such results. This study investigated the impact of solutions with different pH and ionic compositions, eg, normal saline, non-diluted seawater and diluted seawater, on nasal mucosa functional parameters. For this randomized, controlled, blinded, in vitro study, we used airway epithelial cells obtained from 13 nasal polyps explants to measure ciliary beat frequency (CBF) and epithelial wound repair speed (WRS) in response to 3 isotonic nasal irrigation solutions: (1) normal saline 0.9%; (2) non-diluted seawater (Physiomer®); and (3) 30% diluted seawater (Stérimar). The results were compared to control (cell culture medium). Non-diluted seawater enhanced the CBF and the WRS when compared to diluted seawater and to normal saline. When compared to the control, it significantly enhanced CBF and slightly, though nonsignificantly, improved the WRS. Interestingly, normal saline markedly reduced the number of epithelial cells and ciliated cells when compared to the control condition. Our results suggest that the physicochemical features of the nasal wash solution is important because it determines the optimal conditions to enhance CBF and epithelial WRS thus preserving the respiratory mucosa in pathological conditions. Non-diluted seawater obtains the best results on CBF and WRS vs normal saline showing a deleterious effect on epithelial cell function. © 2016 The Authors International Forum of Allergy & Rhinology, published by ARSAAOA, LLC.

  9. Radioisotope dilution technique for determination of vitamin B12 in foods

    International Nuclear Information System (INIS)

    Casey, P.J.; Speckman, K.R.; Ebert, F.J.; Hobbs, W.E.

    1982-01-01

    A radioisotope dilution (RID) method for the determination of vitamin B 12 is presented. The method combines a standard extraction procedure (AOAC 43.108, 12th ed.) with a commercially available RID assay kit. The method was evaluated on a wide range of fortified and unfortified food products. Recovery studies on both groups yielded average recoveries of 98.1 and 95.8%, respectively. Reproducibility data generated from replicate analysis on both groups gave a relative standard deviation of 6.9% for the fortified group and 9.2% for the unfortified group. For the samples studied, the mean vitamin B 12 content determined by the RID method was 8.01 μ/100 g vs a mean of 7.54 μg/100 g by the AOAC microbiological method; the correlation coefficient was r = 0.983

  10. Spin diffusion in the Mn2+ ion system of II-VI diluted magnetic semiconductor heterostructures

    Science.gov (United States)

    Maksimov, A. A.; Yakovlev, D. R.; Debus, J.; Tartakovskii, I. I.; Waag, A.; Karczewski, G.; Wojtowicz, T.; Kossut, J.; Bayer, M.

    2010-07-01

    The magnetization dynamics in diluted magnetic semiconductor heterostructures based on (Zn,Mn)Se and (Cd,Mn)Te were studied optically and simulated numerically. In samples with inhomogeneous magnetic ion distribution, these dynamics are contributed by spin-lattice relaxation and spin diffusion in the Mn spin system. A spin-diffusion coefficient of 7×10-8cm2/s was evaluated for Zn0.99Mn0.01Se from comparison of experiment and theory. Calculations of the exciton giant Zeeman splitting and the magnetization dynamics in ordered alloys and digitally grown parabolic quantum wells show perfect agreement with the experimental data. In both structure types, spin diffusion contributes essentially to the magnetization dynamics.

  11. Quantitative determination of the solidus line in the dilute limit of succinonitrile-camphor alloys

    Science.gov (United States)

    Mota, F. L.; Fabietti, L. M.; Bergeon, N.; Strutzenberg, L. L.; Karma, A.; Billia, B.; Trivedi, R.

    2016-08-01

    Different phase diagram measurements for succinonitrile-camphor alloys to date have yielded different values of the solute partition coefficient and the freezing range of the alloy. These parameters are critical to model solidification microstructure evolution. New measurements are made to precisely characterize the dilute limit of the succinonitrile-camphor phase diagram using thin-sample directional solidification experiments where convection is negligible, so that solute transport in the melt is purely diffusive, and the temperature gradient is constant in time. These results are confirmed through complementary measurements by differential scanning calorimetry and isothermal annealing. Possible measurement uncertainties in previously measured solidus lines are discussed. Experimental results were further confirmed using a boundary layer model of transient planar interface dynamics.

  12. Performace of Dilute Nitride Triple Junction Space Solar Cell Grown by MBE

    Directory of Open Access Journals (Sweden)

    Aho Arto

    2017-01-01

    Full Text Available Dilute nitride arsenide antimonide compounds offer widely tailorable band-gaps, ranging from 0.8 eV to 1.4 eV, for the development of lattice-matched multijunction solar cells with three or more junctions. Here we report on the performance of GaInP/GaAs/GaInNAsSb solar cell grown by molecular beam epitaxy. An efficiency of 27% under AM0 conditions is demonstrated. In addition, the cell was measured at different temperatures. The short circuit current density exhibited a temperature coefficient of 0.006 mA/cm2/°C while the corresponding slope for the open circuit voltage was −6.8 mV/°C. Further efficiency improvement, up to 32%, is projected by better current balancing and structural optimization.

  13. Total cholesterol in serum determined by isotope dilution/mass spectrometry, with liquid-chromatographic separation

    International Nuclear Information System (INIS)

    Takatsu, Akiko; Nishi, Sueo

    1988-01-01

    We describe an accurate, precise method for determination of total serum cholesterol by isotope dilution/mass spectrometry (IDMS) with liquid chromatographic separation. After adding [3,4- 13 C] cholesterol to serum and hydrolyzing the cholesterol esters, we extract the total cholesterol. High-performance liquid chromatography (HPLC) is used to separate the extracted cholesterol for measurement by electron-impact mass spectrometry with use of a direct-insertion device. To evaluate the specificity and the accuracy of this method, we also studied the conventional IDMS method, which involves converting cholesterol to the trimethylsilyl ether and assay by gas chromatography-mass spectrometry with use of a capillary column. The coefficient of variation for the HPLC method was a little larger than for the conventional method, but mean values by each method agreed within 1% for all sera tested. (author)

  14. Hydrodynamic modes, Green-Kubo relations, and velocity correlations in dilute granular gases

    International Nuclear Information System (INIS)

    Brey, J Javier; Ruiz-Montero, M J; Maynar, P; Garcia de Soria, M I

    2005-01-01

    It is shown that the hydrodynamic modes of a dilute granular gas of inelastic hard spheres can be identified, and calculated in the long wavelength limit. Assuming they dominate at long times, formal expressions for the Navier-Stokes transport coefficients are derived. They can be expressed in a form that generalizes the Green-Kubo relations for molecular systems, and it is shown that they can also be evaluated by means of N-particle simulation methods. The form of the hydrodynamic modes to zeroth order in the gradients is used to detect the presence of inherent velocity correlations in the homogeneous cooling state, even in the low density limit. They manifest themselves in the fluctuations of the total energy of the system. The theoretical predictions are shown to be in agreement with molecular dynamics simulations. Relevant related questions deserving further attention are pointed out

  15. Modelling the change in the oxidation coefficient during the aerobic ...

    African Journals Online (AJOL)

    In this work the aerobic degradation of phenol by acclimated activated sludge was studied. Results demonstrate that while the phenol removal rate by acclimated activated sludge follows the Monod model, the oxygen uptake rate obeys a Haldane-type equation. The phenol oxidation coefficient obtained at different intial ...

  16. ERM booster vaccination of Rainbow trout using diluted bacterin

    DEFF Research Database (Denmark)

    Schmidt, Jacob Günther; Henriksen, Niels H.; Buchmann, Kurt

    2016-01-01

    under laboratory conditions extend the protection period. The present field study investigated the applicability of the method under practical farming conditions (freshwater earth ponds supplied by stream water). Primary immersion vaccination of trout (3–4 g) for 30 s in Y. ruckeri bacterin (diluted 1......Enteric Red Mouth Disease ERM caused by Yersinia ruckeri infection is associated with morbidity and mortality in salmonid farming but immersion vaccination of fry may confer some protection for a number of months. Revaccination of rainbow trout, even by use of diluted ERM immersion vaccine, can......:10) in April 2015 was followed 3 months later (July 2015) by 1 h bathing of rainbow trout in bacterin (diluted 1:650 or 1:1700) in order to evaluate if this time saving vaccination methodology can improve immunity and protection. Trout were subjected in farms to natural Y. ruckeri exposure in June and July...

  17. Moderate Dilution of Copper Slag by Natural Gas

    Science.gov (United States)

    Zhang, Bao-jing; Zhang, Ting-an; Niu, Li-ping; Liu, Nan-song; Dou, Zhi-he; Li, Zhi-qiang

    2018-01-01

    To enable use of copper slag and extract the maximum value from the contained copper, an innovative method of reducing moderately diluted slag to smelt copper-containing antibacterial stainless steel is proposed. This work focused on moderate dilution of copper slag using natural gas. The thermodynamics of copper slag dilution and ternary phase diagrams of the slag system were calculated. The effects of blowing time, temperature, matte settling time, and calcium oxide addition were investigated. The optimum reaction conditions were identified to be blowing time of 20 min, reaction temperature of 1250°C, settling time of 60 min, CaO addition of 4% of mass of slag, natural gas flow rate of 80 mL/min, and outlet pressure of 0.1 MPa. Under these conditions, the Fe3O4 and copper contents of the residue were 7.36% and 0.50%, respectively.

  18. Thermal diffusion in dilute nanofluids investigated by photothermal interferometry

    International Nuclear Information System (INIS)

    Philip, J; Nisha, M R

    2010-01-01

    We have carried out a theoretical analysis of the dependence of the particle mass fraction on the thermal diffusivity of dilute suspensions of nanoparticles in liquids (dilute nanofluids). The analysis takes in to account adsorption of an ordered layer of solvent molecules around the nanoparticles. It is found that thermal diffusivity decreases with mass fraction for sufficiently small particle sizes. Beyond a critical particle size thermal diffusivity begins to increase with mass fraction for the same system. The results have been verified experimentally by measuring the thermal diffusivity of dilute suspensions of TiO 2 nanoparticles dispersed in polyvinyl alcohol (PVA) medium. The effect is attributed to Kapitza resistance of thermal waves in the medium.

  19. Multi-element isotope dilution analyses using ICP-MS

    International Nuclear Information System (INIS)

    Volpe, A.M.

    1996-01-01

    Presently, 37 elements ranging from light (Li,B) through transition metals, noble, rare earth and heavy elements, to actinides and transuranics (Pu, Am, Cm) are measured by isotope dilution at Lawrence Livermore National Laboratory. Projects range from geological and hydrological to biological. The research goal is to measure accurately many elements present in diverse matrices at trace (ppb) levels using isotope dilution methods. Major advantages of isotope dilution methods are accuracy, elimination of ion intensity calibration, and quantitation for samples that require chemical separation. Accuracy depends on tracer isotope calibration, tracer-sample isotopic equilibration, and appropriate background, isobaric and mass bias corrections. Propagation of isotope ratio error due to improper tracer isotope addition is a major concern with multi-element analyses when abundances vary widely. 11 refs., 3 figs

  20. First-principle natural band alignment of GaN / dilute-As GaNAs alloy

    Directory of Open Access Journals (Sweden)

    Chee-Keong Tan

    2015-01-01

    Full Text Available Density functional theory (DFT calculations with the local density approximation (LDA functional are employed to investigate the band alignment of dilute-As GaNAs alloys with respect to the GaN alloy. Conduction and valence band positions of dilute-As GaNAs alloy with respect to the GaN alloy on an absolute energy scale are determined from the combination of bulk and surface DFT calculations. The resulting GaN / GaNAs conduction to valence band offset ratio is found as approximately 5:95. Our theoretical finding is in good agreement with experimental observation, indicating the upward movements of valence band at low-As content dilute-As GaNAs are mainly responsible for the drastic reduction of the GaN energy band gap. In addition, type-I band alignment of GaN / GaNAs is suggested as a reasonable approach for future device implementation with dilute-As GaNAs quantum well, and possible type-II quantum well active region can be formed by using InGaN / dilute-As GaNAs heterostructure.

  1. The effect of dilute acid pre-treatment process in bioethanol production from durian (Durio zibethinus) seeds waste

    Science.gov (United States)

    Ghazali, K. A.; Salleh, S. F.; Riayatsyah, T. M. I.; Aditiya, H. B.; Mahlia, T. M. I.

    2016-03-01

    Lignocellulosic biomass is one of the promising feedstocks for bioethanol production. The process starts from pre-treatment, hydrolysis, fermentation, distillation and finally obtaining the final product, ethanol. The efficiency of enzymatic hydrolysis of cellulosic biomass depends heavily on the effectiveness of the pre-treatment step which main function is to break the lignin structure of the biomass. This work aims to investigate the effects of dilute acid pre-treatment on the enzymatic hydrolysis of durian seeds waste to glucose and the subsequent bioethanol fermentation process. The yield of glucose from dilute acid pre-treated sample using 0.6% H2SO4 and 5% substrate concentration shows significant value of 23.4951 g/L. Combination of dilute acid pre-treatment and enzymatic hydrolysis using 150U of enzyme able to yield 50.0944 g/L of glucose content higher compared to normal pre-treated sample of 8.1093 g/L. Dilute acid pre-treatment sample also shows stable and efficient yeast activity during fermentation process with lowest glucose content at 2.9636 g/L compared to 14.7583g/L for normal pre-treated sample. Based on the result, it can be concluded that dilute acid pre-treatment increase the yield of ethanol from bioethanol production process.

  2. Factorization of Transport Coefficients in Macroporous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2000-01-01

    We prove the fundamental theorem about factorization of the phenomenological coefficients for transport in macroporous media. By factorization we mean the representation of the transport coefficients as products of geometric parameters of the porous medium and the parameters characteristic...

  3. Enthalpy of dilution and volumetric properties of N-glycylglycine in aqueous xylitol solutions at T = 298.15 K

    International Nuclear Information System (INIS)

    Liu Min; Wang Lili; Li Guangqian; Dong Lina; Sun Dezhi; Zhu Lanying; Di Youying

    2011-01-01

    Highlights: → Enthalpies of dilution of N-glycylglycine in aqueous xylitol solutions were determined at 298.15 K. → The homogeneous enthalpic interaction coefficients were calculated. → Apparent molar volumes of the ternary systems were calculated from the data of densities. → Limiting partial molar volumes and limiting partial molar volumes of transfer were deduced. - Abstract: The enthalpy of dilution of N-glycylglycine (Δ dil H m ) in aqueous xylitol solutions has been determined by means of flow-mix isothermal microcalorimetry at the temperature of 298.15 K. The homogeneous enthalpic interaction coefficients (h 2 , h 3 , and h 4 ) which characterize the interactions of examined N-glycylglycine in aqueous xylitol solutions have been calculated according to the excess enthalpy concept based on the values of dilution enthalpy. It has been found that the enthalpic pair interaction coefficients (h 2 ) in the systems investigated are negative and become less negative as the molality of xylitol increases. Values of the density (ρ) of the ternary homogeneous systems were also measured with a quartz vibrating-tube densimeter at the temperature of 298.15 K. The values of the apparent molar volume (V φ ) of the ternary systems were calculated from the data of density, which have been used to deduce limiting partial molar volumes of N-glycylglycine (V φ o ) and limiting partial molar volumes of transfer (Δ trs V φ o ) from water to aqueous xylitol solutions at different concentrations. The results have been discussed based on solute-solute interactions and solvation effects.

  4. Enthalpy of dilution and volumetric properties of N-glycylglycine in aqueous xylitol solutions at T = 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Liu Min, E-mail: panpanliumin@163.co [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Wang Lili; Li Guangqian; Dong Lina; Sun Dezhi [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Zhu Lanying [College of Life Science and Bioengineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Di Youying [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China)

    2011-06-15

    Highlights: Enthalpies of dilution of N-glycylglycine in aqueous xylitol solutions were determined at 298.15 K. The homogeneous enthalpic interaction coefficients were calculated. Apparent molar volumes of the ternary systems were calculated from the data of densities. Limiting partial molar volumes and limiting partial molar volumes of transfer were deduced. - Abstract: The enthalpy of dilution of N-glycylglycine ({Delta}{sub dil}H{sub m}) in aqueous xylitol solutions has been determined by means of flow-mix isothermal microcalorimetry at the temperature of 298.15 K. The homogeneous enthalpic interaction coefficients (h{sub 2}, h{sub 3}, and h{sub 4}) which characterize the interactions of examined N-glycylglycine in aqueous xylitol solutions have been calculated according to the excess enthalpy concept based on the values of dilution enthalpy. It has been found that the enthalpic pair interaction coefficients (h{sub 2}) in the systems investigated are negative and become less negative as the molality of xylitol increases. Values of the density ({rho}) of the ternary homogeneous systems were also measured with a quartz vibrating-tube densimeter at the temperature of 298.15 K. The values of the apparent molar volume (V{sub {phi}}) of the ternary systems were calculated from the data of density, which have been used to deduce limiting partial molar volumes of N-glycylglycine (V{sub {phi}}{sup o}) and limiting partial molar volumes of transfer ({Delta}{sub trs}V{sub {phi}}{sup o}) from water to aqueous xylitol solutions at different concentrations. The results have been discussed based on solute-solute interactions and solvation effects.

  5. Improved analytical procedure for the determination of 210Pb and 210Po using alpha-spectrometric isotope dilution

    International Nuclear Information System (INIS)

    Urnezis, P.W.; Holtzman, R.B.

    1981-01-01

    An isotope dilution method has been incorporated into the 210 Pb- 210 Po analysis. A known amount of 209 Po is added to the sample before analysis. Then both 209 Po and 210 Po are deposited on a silver planchet which is assayed in an alpha spectrometer to determine the activities of each isotope. The recoveries generally range from 70% to 90%

  6. USE OF A MICRO TITLE PLATE DILUTION ASSAY TO MEASURE ACTIVITY OF ANTIFUNGAL COMPOUNDS AGAINST Mycosphaerella Fijiensis, MORELET. UTILIZACIÓN DE UN ENSAYO DE DILUCIÓN EN MICROPLATOS PARA MEDIR LA ACTIVIDAD ANTIFÚNGICA DE SUSTANCIAS CONTRA Mycosphaerella fijiensis, MORELET.

    Directory of Open Access Journals (Sweden)

    Jorge Enrique Peláez Montoya

    2006-12-01

    Full Text Available Black Sigatoka, caused by the fungus Mycosphaerella fijiensis is the most important disease in banana plantations. The fungus is controlled mainly by fungicide applications with an annual cost of about 350 million dollars in Latin and Central America. Due to the appearance of resistant strains and to the economical and environmental impact caused by the extensive use of fungicides, accurate methods are necessary for monitoring the fungal sensitivity to these agents. In this paper we describe the standarization of a method based on microplate dilutions that measures IC50 of different antifungal compounds against single ascospore cultures of M. fijiensis. The method was used to measure the sensitivity of 30 strains collected from different regions in Colombia against Propiconazol, Benomyl and Azoxystrobin. Used at a larger scale, this method could be useful to monitor M. fijiensis sensitivity against fungicides and to search for new compounds with activity against the fungus.La Sigatoka negra, causada por el hongo Mycosphaerella fijiensis, es la enfermedad más importante que afecta plantaciones de banano y plátano. El hongo es controlado principalmente mediante fungicidas químicos con un costo anual de cerca de 350 millones de dólares para América latina y 25 millones de dólares para Colombia. Debido al desarrollo de cepas del hongo resistentes a los fungicidas y a las consecuencias que para el medio ambiente tiene su uso intensivo, es importante el desarrollo de métodos que permitan monitorear de una manera precisa la aparición de resistencia. También es de gran utilidad disponer de un método que permita evaluar en forma sencilla la actividad de nuevas sustancias contra el hongo. En este artículo describimos la estandarización de un método basado en diluciones en microplatos que permite determinar la IC50 de diversos compuestos antifungicos contra cultivos monospóricos de M. fijiensis. Para su validación, el método fue utilizado

  7. How Consumers’ Styles of Thinking Can Control Brand Dilution

    Directory of Open Access Journals (Sweden)

    Monga Alokparna Basu

    2018-05-01

    Full Text Available Understanding consumers’ ways of thinking can help identify strategies to limit brand damage and elicit more favorable reactions from disapproving consumers. Analytic thinkers’ beliefs about a brand are diluted when they see negative information; those of holistic thinkers remain unaffected. While both analytic and holistic thinkers blame the brand equally for quality and manufacturing problems, holistic thinkers are more likely to blame contextual factors outside of the brand than analytic thinkers. This ability of holistic thinkers to focus on the outside context is the reason why their brand beliefs are not diluted.

  8. Computer registration of radioactive indicator-dilution curves.

    Science.gov (United States)

    Shepherd, A P; Perry, M A; Alexander, G M; Granger, D N; Riedel, G L; Kvietys, P R; Franke, C P

    1983-12-01

    A system is described for recording indicator-dilution curves produced by gamma radiation-emitting tracers. The system consists of a flow-through cuvette in a well counter, appropriate commercially available gamma radiation-detecting equipment, an Apple II computer, and a two-channel pulse-counting interface of our own design. With the counting interface and the software described here, an investigator can simultaneously record two indicator-dilution curves produced by gamma emitters. Instead of having to wait hours or days for results, the investigator can watch the data being recorded and display the results in graphic form almost immediately after each injection.

  9. GRAIN-BOUNDARY PRECIPITATION UNDER IRRADIATION IN DILUTE BINARY ALLOYS

    Institute of Scientific and Technical Information of China (English)

    S.H. Song; Z.X. Yuan; J. Liu; R.G.Faulkner

    2003-01-01

    Irradiation-induced grain boundary segregation of solute atoms frequently bring about grain boundary precipitation of a second phase because of its making the solubility limit of the solute surpassed at grain boundaries. Until now the kinetic models for irradiation-induced grain boundary precipitation have been sparse. For this reason, we have theoretically treated grain boundary precipitation under irradiation in dilute binary alloys. Predictions ofγ'-Ni3Si precipitation at grain boundaries ave made for a dilute Ni-Si alloy subjected to irradiation. It is demonstrated that grain boundary silicon segregation under irradiation may lead to grain boundaryγ'-Ni3 Si precipitation over a certain temperature range.

  10. Dilution and volatilization of groundwater contaminant discharges in streams

    DEFF Research Database (Denmark)

    Aisopou, Angeliki; Bjerg, Poul Løgstrup; Sonne, Anne Thobo

    2015-01-01

    measurement. The solution was successfully applied to published field data obtained in a large and a small Danish stream and provided valuable information on the risk posed by the groundwater contaminant plumes. The results provided by the dilution and volatilization model are very different to those obtained......An analytical solution to describe dilution and volatilization of a continuous groundwater contaminant plume into streams is developed for risk assessment. The location of groundwater plume discharge into the stream (discharge through the side versus bottom of the stream) and different...

  11. Test plan for tank 241-AN-104 dilution studies

    International Nuclear Information System (INIS)

    Herting, D.L.

    1998-01-01

    Tank 241-AN-104 (104-AN) has been identified as the one of the first tanks to be retrieved for low level waste pretreatment and immobilization. Retrieval of the tank waste will require dilution. Laboratory tests are needed to determine the amount and type of dilution required for safe retrieval and transfer of feed and to re-dissolve major soluble sodium salts while not precipitating out other salts. The proposed laboratory tests are described in this document. Tank 241-AN-104 is on the Hydrogen Watch List

  12. Dynamics of dilute disordered models: A solvable case

    International Nuclear Information System (INIS)

    Semerjian, Guilhem; Cugliandolo, Leticia F.

    2003-09-01

    We study the dynamics of a dilute spherical model with two body interactions and random exchanges. We analyze the Langevin equations and we introduce a functional variational method to study generic dilute disordered models. A crossover temperature replaces the dynamic transition of the fully-connected limit. There are two asymptotic regimes, one determined by the central band of the spectral density of the interactions and a slower one determined by localized configurations on sites with high connectivity. We confront the behavior of this model to the one of real glasses. (author)

  13. High field Moessbauer study of dilute Ir-(Fe) alloys

    International Nuclear Information System (INIS)

    Takabatake, Toshiro; Mazaki, Hiromasa; Shinjo, Teruya.

    1981-01-01

    The magnetic behavior of very dilute Fe impurities in Ir has been studied by means of Moessbauer measurement in external fields up to 80 kOe at 4.2 K. The saturation hyperfine field increases in proportion to the external field up to the maximum magnetic field available. This means that for a localized spin fluctuation system IrFe, the effective magnetic moment associated with Fe impurities is induced in proportion to the external field. No anomalous spectrum was observed with a very dilute sample (--10 ppm 57 Co), indicating that the interaction between impurities is responsible for the anomalous spectrum previously observed with a less homogeneous sample. (author)

  14. Anomalous Seebeck coefficient in boron carbides

    International Nuclear Information System (INIS)

    Aselage, T.L.; Emin, D.; Wood, C.; Mackinnon, I.D.R.; Howard, I.A.

    1987-01-01

    Boron carbides exhibit an anomalously large Seebeck coefficient with a temperature coefficient that is characteristic of polaronic hopping between inequivalent sites. The inequivalence in the sites is associated with disorder in the solid. The temperature dependence of the Seebeck coefficient for materials prepared by different techniques provides insight into the nature of the disorder

  15. Standards for Standardized Logistic Regression Coefficients

    Science.gov (United States)

    Menard, Scott

    2011-01-01

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

  16. Soccer Ball Lift Coefficients via Trajectory Analysis

    Science.gov (United States)

    Goff, John Eric; Carre, Matt J.

    2010-01-01

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

  17. Symmetry chains and adaptation coefficients

    International Nuclear Information System (INIS)

    Fritzer, H.P.; Gruber, B.

    1985-01-01

    Given a symmetry chain of physical significance it becomes necessary to obtain states which transform properly with respect to the symmetries of the chain. In this article we describe a method which permits us to calculate symmetry-adapted quantum states with relative ease. The coefficients for the symmetry-adapted linear combinations are obtained, in numerical form, in terms of the original states of the system and can thus be represented in the form of numerical tables. In addition, one also obtains automatically the matrix elements for the operators of the symmetry groups which are involved, and thus for any physical operator which can be expressed either as an element of the algebra or of the enveloping algebra. The method is well suited for computers once the physically relevant symmetry chain, or chains, have been defined. While the method to be described is generally applicable to any physical system for which semisimple Lie algebras play a role we choose here a familiar example in order to illustrate the method and to illuminate its simplicity. We choose the nuclear shell model for the case of two nucleons with orbital angular momentum l = 1. While the states of the entire shell transform like the smallest spin representation of SO(25) we restrict our attention to its subgroup SU(6) x SU(2)/sub T/. We determine the symmetry chains which lead to total angular momentum SU(2)/sub J/ and obtain the symmetry-adapted states for these chains

  18. Limits of the memory coefficient in measuring correlated bursts

    Science.gov (United States)

    Jo, Hang-Hyun; Hiraoka, Takayuki

    2018-03-01

    Temporal inhomogeneities in event sequences of natural and social phenomena have been characterized in terms of interevent times and correlations between interevent times. The inhomogeneities of interevent times have been extensively studied, while the correlations between interevent times, often called correlated bursts, are far from being fully understood. For measuring the correlated bursts, two relevant approaches were suggested, i.e., memory coefficient and burst size distribution. Here a burst size denotes the number of events in a bursty train detected for a given time window. Empirical analyses have revealed that the larger memory coefficient tends to be associated with the heavier tail of the burst size distribution. In particular, empirical findings in human activities appear inconsistent, such that the memory coefficient is close to 0, while burst size distributions follow a power law. In order to comprehend these observations, by assuming the conditional independence between consecutive interevent times, we derive the analytical form of the memory coefficient as a function of parameters describing interevent time and burst size distributions. Our analytical result can explain the general tendency of the larger memory coefficient being associated with the heavier tail of burst size distribution. We also find that the apparently inconsistent observations in human activities are compatible with each other, indicating that the memory coefficient has limits to measure the correlated bursts.

  19. Effect of diluting starch mixtures with bacterial amylase on the heat treatment of the grain

    Energy Technology Data Exchange (ETDEWEB)

    Ustinikov, B A; Gromov, S I; Poluyanova, M T

    1971-01-01

    A higher yield of alcohol can be obtained from finely ground grain by diluting the mixtures prior to boiling down with amylolyic enzymes or acids, using thermophilic bacteria. Bacterium diastaticus can withstand temperature as high as 90 to 95/sup 0/C. Experiments are described for studying the effect of time and temperature of boiling on ground grain of different particle size, and of preliminary dilution of the mashes with bacterial amylase. The particle sizes used in the experiment were 0.7 to 1, 1.5 to 2 and 2.5 to 3 mm. The 40 g samples were diluted with 140 ml water and 2 vol % liquid bacterial diastaticus culture with an activity of 160 units/100 ml. 40 minutes on a water bath caused gelation of the starch. Following this treatment, the samples were autoclaved for 10 to 120 minutes at 133, 141, 151 and 158/sup 0/C. Results, expressed in graph form, show that addition of bacterial amylase enabled the grain mash boiling period to be shortened.

  20. Can tritiated water-dilution space accurately predict total body water in chukar partridges

    International Nuclear Information System (INIS)

    Crum, B.G.; Williams, J.B.; Nagy, K.A.

    1985-01-01

    Total body water (TBW) volumes determined from the dilution space of injected tritiated water have consistently overestimated actual water volumes (determined by desiccation to constant mass) in reptiles and mammals, but results for birds are controversial. We investigated potential errors in both the dilution method and the desiccation method in an attempt to resolve this controversy. Tritiated water dilution yielded an accurate measurement of water mass in vitro. However, in vivo, this method yielded a 4.6% overestimate of the amount of water (3.1% of live body mass) in chukar partridges, apparently largely because of loss of tritium from body water to sites of dissociable hydrogens on body solids. An additional source of overestimation (approximately 2% of body mass) was loss of tritium to the solids in blood samples during distillation of blood to obtain pure water for tritium analysis. Measuring tritium activity in plasma samples avoided this problem but required measurement of, and correction for, the dry matter content in plasma. Desiccation to constant mass by lyophilization or oven-drying also overestimated the amount of water actually in the bodies of chukar partridges by 1.4% of body mass, because these values included water adsorbed onto the outside of feathers. When desiccating defeathered carcasses, oven-drying at 70 degrees C yielded TBW values identical to those obtained from lyophilization, but TBW was overestimated (0.5% of body mass) by drying at 100 degrees C due to loss of organic substances as well as water

  1. Energy coefficients for a propeller series

    DEFF Research Database (Denmark)

    Olsen, Anders Smærup

    2004-01-01

    The efficiency for a propeller is calculated by energy coefficients. These coefficients are related to four types of losses, i.e. the axial, the rotational, the frictional, and the finite blade number loss, and one gain, i.e. the axial gain. The energy coefficients are derived by use...... of the potential theory with the propeller modelled as an actuator disk. The efficiency based on the energy coefficients is calculated for a propeller series. The results show a good agreement between the efficiency based on the energy coefficients and the efficiency obtained by a vortex-lattice method....

  2. Calculation of self-diffusion coefficients in iron

    Directory of Open Access Journals (Sweden)

    Baohua Zhang

    2014-01-01

    Full Text Available On the basis of available P-V-T equation of state of iron, the temperature and pressure dependence of self-diffusion coefficients in iron polymorphs (α, δ, γ and ɛ phases have been successfully reproduced in terms of the bulk elastic and expansivity data by means of a thermodynamical model that interconnects point defects parameters with bulk properties. The calculated diffusion parameters, such as self-diffusion coefficient, activation energy and activation volume over a broad temperature range (500-2500 K and pressure range (0-100 GPa, compare favorably well with experimental or theoretical ones when the uncertainties are considered.

  3. post-jomtien policy dilutions: infrastructural & quality norms

    Indian Academy of Sciences (India)

    Operation Blackboard norms diluted – from 3 teachers-3 rooms per primary school to 2 teachers-2 rooms per primary school. Regular teacher replaced by under-qualified, untrained, under-paid Para-teachers appointed on short-term contracts. EGS – No provision for school buildings or teaching aids. Multi-grade Teaching ...

  4. Coherence and stiffness of spin waves in diluted ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Turek, Ilja; Kudrnovský, Josef; Drchal, Václav

    2016-01-01

    Roč. 94, č. 17 (2016), č. článku 174447. ISSN 2469-9950 R&D Projects: GA ČR GA15-13436S Institutional support: RVO:68081723 ; RVO:68378271 Keywords : spin wave s * diluted ferromagnets * disordered systems Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016

  5. Procedures for accurately diluting and dispensing radioactive solutions

    International Nuclear Information System (INIS)

    1975-01-01

    The technique currently used by various laboratories participating in international comparisons of radioactivity measurements are surveyed and recommendations for good laboratory practice established. Thus one describes, for instance, the preparation of solutions, dilution techniques, the use of 'pycnometers', weighing procedures (including buyoancy correction), etc. It should be possible to keep random and systematic uncertainties below 0.1% of the final result

  6. A simple approximation method for dilute Ising systems

    International Nuclear Information System (INIS)

    Saber, M.

    1996-10-01

    We describe a simple approximate method to analyze dilute Ising systems. The method takes into consideration the fluctuations of the effective field, and is based on a probability distribution of random variables which correctly accounts for all the single site kinematic relations. It is shown that the simplest approximation gives satisfactory results when compared with other methods. (author). 12 refs, 2 tabs

  7. Determination of dilution and quality control of total and anti ...

    African Journals Online (AJOL)

    Objective: To determine the correct dilution and Quality control commercial ELISA of total and anti-measles antibodies for HIV infected pregnant women. Design: A laboratory based study. Setting: The University of Nairobi, Department of Paediatrics laboratory. Subjects: HIV infected pregnant women enrolled and exposed to ...

  8. Quality of potential harmonics expansion method for dilute Bose ...

    Indian Academy of Sciences (India)

    Abstract. We present and examine an approximate but ab initio many-body approach, viz., potential harmonics expansion method (PHEM), which includes two-body correla- tions for dilute Bose–Einstein condensates. Comparing the total ground state energy for three trapped interacting bosons calculated in PHEM with the ...

  9. Bioethanol productions from rice polish by optimization of dilute acid ...

    African Journals Online (AJOL)

    Lignocellulose materials are abundant renewable resource for the production of biofuel from fermentative organism (Sacchromyces cervesiae). Rice polish is cheapest and abundant lignocelluloses resource and has potential to produce bioethanol. The main steps for the conversion of biomass into glucose required dilute ...

  10. Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

    African Journals Online (AJOL)

    NICOLAAS

    2014-06-23

    Jun 23, 2014 ... The influence of deanol on the corrosion behaviour of mild steel in dilute sulphuric acid with sodium ... the formation of a complex precipitate of protective film, which ... silicon carbide abrasive papers of 80, 120, 220, 800 and 1000 grit ...... ions in sulphuric acid on the corrosion behaviour of stainless steel,.

  11. Kinetic-sound propagation in dilute gas mixtures

    International Nuclear Information System (INIS)

    Campa, A.; Cohen, E.G.D.

    1989-01-01

    Kinetic sound is predicted in dilute disparate-mass binary gas mixtures, propagating exclusively in the light compound and much faster than ordinary sound. It should be detectable by light-scattering experiments, as an extended shoulder in the scattering cross section for large frequencies. As an example, H 2 -Ar mixtures are discussed

  12. Thermodynamics of a dilute XX chain in a field

    Energy Technology Data Exchange (ETDEWEB)

    Timonin, P. N., E-mail: pntim@live.ru [Southern Federal University, Physics Research Institute (Russian Federation)

    2016-06-15

    Gapless phases in ground states of low-dimensional quantum spin systems are rather ubiquitous. Their peculiarity is a remarkable sensitivity to external perturbations due to permanent criticality of such phases manifested by a slow (power-low) decay of pair correlations and the divergence of the corresponding susceptibility. A strong influence of various defects on the properties of the system in such a phase can then be expected. Here, we consider the influence of vacancies on the thermodynamics of the simplest quantum model with a gapless phase, the isotropic spin-1/2 XX chain. The existence of the exact solution of this model gives a unique opportunity to describe in detail the dramatic effect of dilution on the gapless phase—the appearance of an infinite series of quantum phase transitions resulting from level crossing under the variation of a longitudinal magnetic field. We calculate the jumps in the field dependences of the ground-state longitudinal magnetization, susceptibility, entropy, and specific heat appearing at these transitions and show that they result in a highly nonlinear temperature dependence of these parameters at low T. Also, the effect of enhancement of the magnetization and longitudinal correlations in the dilute chain is established. The changes of the pair spin correlators under dilution are also analyzed. The universality of the mechanism of the quantum transition generation suggests that similar effects of dilution can also be expected in gapless phases of other low-dimensional quantum spin systems.

  13. 21 CFR 172.710 - Adjuvants for pesticide use dilutions.

    Science.gov (United States)

    2010-04-01

    ... Section 172.710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives § 172.710 Adjuvants for pesticide use dilutions. The...

  14. Electrochemical reduction of metal ions in dilute solution using hydrogen

    NARCIS (Netherlands)

    Portegies Zwart, I.; Wijnbelt, E.C.W.; Janssen, L.J.J.

    1995-01-01

    Reduction of metal ions in dilute solutions is of great interest for purification of waste waters and process liquids. A new electrochemical cell has been introduced. This cell - a GBC-cell - is a combination of a gasdiffusion electrode in direct contact with a packed bed of carbon particles.

  15. Electrochemical reduction of dilute chromate solutions on carbon felt electrodes

    NARCIS (Netherlands)

    Frenzel, Ines; Frenzel, I.; Holdik, Hans; Barmashenko, Vladimir; Stamatialis, Dimitrios; Wessling, Matthias

    2006-01-01

    Carbon felt is a potential material for electrochemical reduction of chromates. Very dilute solutions may be efficiently treated due to its large specific surface area and high porosity. In this work, the up-scaling of this technology is investigated using a new type of separated cell and

  16. Electrochemical reduction of nickel ions from dilute solutions

    NARCIS (Netherlands)

    Njau, K.N.; Janssen, L.J.J.

    1995-01-01

    Electrochemical reduction of nickel ions in dilute solution using a divided GBC-cell is of interest for purification of waste waters. A typical solution to be treated is the effluent from steel etching processes which contain low quantities of nickel, chromate and chromium ions. Reduction of

  17. 21 CFR 864.5240 - Automated blood cell diluting apparatus.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated blood cell diluting apparatus. 864.5240 Section 864.5240 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology Devices...

  18. Phase diagrams of site diluted ferromagnetic thin film

    International Nuclear Information System (INIS)

    Hamedoun, M.; Bouslykhane, K.; Bakrim, H.; Hourmatallah, A.; Benzakour, N.; Masrour, R.

    2006-01-01

    The phase transition properties of Ising, classical XY and Heisenberg of diluted ferromagnetic thin film are studied by the method of exact high-temperature series expansions extrapolated with the Pade approximants method. The reduced critical temperature τ c of the diluted ferromagnetic thin films is studied as a function of film thickness L and the exchange interactions in the bulk J b , in the surface J s and between surface and nearest-neighbour layer J - bar . It is found that τ c increases with the exchange interactions of surface and L. The magnetic phase diagram (τ c versus dilution x) is obtained. A critical value of the surface exchange interaction above which the surface magnetism appears is obtained. The dependence of the critical parameter of surface reduced coupling R 2 c as a function of the dilution x and the ratio of the exchange interaction between the surface and nearest-neighbour layer to the bulk one R 1 for the three studied models has been investigated. The percolation threshold is defined as the concentration x p at which τ c =0. The obtained values are x p ∼0.2 in the bulk and x p ∼0.4 at the surface

  19. Determination of photooxygenation products of rotenone with isotope dilution method

    International Nuclear Information System (INIS)

    Chubachi, Mitsuo; Hamada, Masayuki

    1975-01-01

    When rotenone dissolved in certain solvent was photochemically oxidized, rotenolones, dehydrorotenone and rotenonone were obtained as main products. In order to determine the quantitative yields of these compounds in photooxygenation products, four compounds mentioned above were labeled with carbon-14 and the isotope dilution method by these labeled compounds was applied to the product analysis. (auth.)

  20. Analysis of boron dilution in a four-loop PWR

    International Nuclear Information System (INIS)

    Sun, J.G.; Sha, W.T.

    1995-03-01

    Thermal mixing and boron dilution in a pressurized water reactor were analyzed with COMMIX codes. The reactor system was the four-loop Zion reactor. Two boron dilution scenarios were analyzed. In the first scenario, the plant is in cold shutdown and the reactor coolant system has just been filled after maintenance on the steam generators. To flush the air out of the steam generator tubes, a reactor coolant pump (RCP) is started, with the water in the pump suction line devoid of boron and at the same temperature as the coolant in the system. In the second scenario, the plant is at hot standby and the reactor coolant system has been heated to operating temperature after a long outage. It is assumed that an RCP is started, with the pump suction line filled with cold unborated water, forcing a slug of diluted coolant down the downcomer and subsequently through the reactor core. The subsequent transient thermal mixing and boron dilution that would occur in the reactor system is simulated for these two scenarios. The reactivity insertion rate and the total reactivity are evaluated and a sensitivity study is performed to assess the accuracy of the numerical modeling of the geometry of the reactor coolant system

  1. In vitro dilutions of thioridaxine with potential to enhance antibiotic ...

    African Journals Online (AJOL)

    Gram staining, catalase test and coagulase test were done on the resulting colonies to further confirm the strains as S. aureus. Antibiotic susceptibility test was done by agar disc diffusion method using sterile Mueller- Hinton agar plates before and after treatment with laboratory dilutions of thioridaxine. S. aureus strains 1, ...

  2. Optimisation of Dilute Sulphuric Acid Hydrolysis of Waste ...

    African Journals Online (AJOL)

    Dilute sulphuric acid hydrolysis of waste paper was investigated in this study. The effects of acid concentration, time, temperature and liquid to solid ratio on the total reducing sugar concentration were studied over three levels using a four variable Box-Behnken design (BBD). A statistical model was developed for the ...

  3. Atomic displacements in dilute alloys of Cr, Nb and Mo

    Indian Academy of Sciences (India)

    physics pp. 497–514. Atomic displacements in dilute alloys of Cr, Nb and Mo ... used to calculate dynamical matrix and the impurity-induced forces up to second nearest ... origin, the lattice is strained, and the host atoms get displaced to new ...

  4. Color dilution alopecia in a blue Doberman pinscher crossbreed

    OpenAIRE

    Perego, Roberta; Proverbio, Daniela; Roccabianca, Paola; Spada, Eva

    2009-01-01

    A 6-year-old male, blue Doberman pinscher crossbreed was presented with coat abnormalities; in particular, flank alopecia and pruritus. Based on medical the history, clinical evidence, and histopathological examination, color dilution alopecia was diagnosed. The dog was with oral melatonin treated for 3 months without success.

  5. Color dilution alopecia in a blue Doberman pinscher crossbreed.

    Science.gov (United States)

    Perego, Roberta; Proverbio, Daniela; Roccabianca, Paola; Spada, Eva

    2009-05-01

    A 6-year-old male, blue Doberman pinscher crossbreed was presented with coat abnormalities; in particular, flank alopecia and pruritus. Based on medical the history, clinical evidence, and histopathological examination, color dilution alopecia was diagnosed. The dog was with oral melatonin treated for 3 months without success.

  6. Does the dilution effect generally occur in animal diseases?

    NARCIS (Netherlands)

    Huang, Zheng Y.X.; Yu, Yang; Langevelde, Van Frank; Boer, De Willem F.

    2017-01-01

    The dilution effect (DE) has been reported in many diseases, but its generality is still highly disputed. Most current criticisms of DE are related to animal diseases. Particularly, some critical studies argued that DE is less likely to occur in complex environments. Here our meta-analyses

  7. Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

    African Journals Online (AJOL)

    The influence of deanol on the corrosion behaviour of mild steel in dilute sulphuric acid with sodium chloride addition was studied by means of mass-loss, potentiodynamic polarization, electrode potential monitoring, scanning electron microscopy and statistical analysis. Results show that deanol performed excellently with ...

  8. Novel understanding of calcium silicate hydrate from dilute hydration

    KAUST Repository

    Zhang, Lina; Yamauchi, Kazuo; Li, Zongjin; Zhang, Xixiang; Ma, Hongyan; Ge, Shenguang

    2017-01-01

    The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10

  9. Sugar yields from dilute oxalic acid pretreatment of maple wood compared to those with other dilute acids and hot water.

    Science.gov (United States)

    Zhang, Taiying; Kumar, Rajeev; Wyman, Charles E

    2013-01-30

    Dilute oxalic acid pretreatment was applied to maple wood to improve compatibility with downstream operations, and its performance in pretreatment and subsequent enzymatic hydrolysis was compared to results for hydrothermal and dilute hydrochloric and sulfuric acid pretreatments. The highest total xylose yield of ∼84% of the theoretical maximum was for both 0.5% oxalic and sulfuric acid pretreatment at 160 °C, compared to ∼81% yield for hydrothermal pretreatment at 200 °C and for 0.5% hydrochloric acid pretreatment at 140 °C. The xylooligomer fraction from dilute oxalic acid pretreatment was only 6.3% of the total xylose in solution, similar to results with dilute hydrochloric and sulfuric acids but much lower than the ∼70% value for hydrothermal pretreatment. Combining any of the four pretreatments with enzymatic hydrolysis with 60 FPU cellulase/g of glucan plus xylan in the pretreated maple wood resulted in virtually the same total glucose plus xylose yields of ∼85% of the maximum possible. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Solubility and diffusion coefficient of oxygen in silicon

    International Nuclear Information System (INIS)

    Itoh, Yoshiko; Nozaki, Tadashi

    1985-01-01

    The solubility and diffusion coefficient of oxygen in silicon between 1000 0 C and 1375 0 C were examined by charged particle activation analysis with the 16 O( 3 He,p) 18 F reaction, in which oxygen was activated with an equal probability over the depth of up to 250μm by a specially devised apparatus. Silicon wafers of known histories were heated in oxygen or argon for 12 to 473 hours, and the resultant oxygen depth profiles were determined by the activation, subsequent stepwise etching and 18 F activity measurement. The solubility thus obtained is given as 9.3 x 10 21 exp[-27.6kcal mol -1 /RT] at.cm -3 ; the diffusion coefficient has been found to be approximated as 3.2 exp[-67.1kcal mol -1 /RT] cm 2 s -1 over 1150 0 C, under which the apparent activation energy seems to decrease with decrease of temperature. (author)

  11. A drying coefficient for building materials

    DEFF Research Database (Denmark)

    Scheffler, Gregor Albrecht; Plagge, Rudolf

    2009-01-01

    coefficient is defined which can be determined based on measured drying data. The correlation of this coefficient with the water absorption and the vapour diffusion coefficient is analyzed and its additional information content is critically challenged. As result, a drying coefficient has been derived......The drying experiment is an important element of the hygrothermal characterisation of building materials. Contrary to other moisture transport experiments as the vapour diffusion and the water absorption test, it is until now not possible to derive a simple coefficient for the drying. However......, in many cases such a coefficient would be highly appreciated, e.g. in interaction of industry and research or for the distinction and selection of suitable building materials throughout design and practise. This article first highlights the importance of drying experiments for hygrothermal...

  12. SBR treatment of olive mill wastewaters: dilution or pre-treatment?

    Science.gov (United States)

    Farabegoli, G; Chiavola, A; Rolle, E

    2012-01-01

    The olive-oil extraction industry is an economically important activity for many countries of the Mediterranean Sea area, with Spain, Greece and Italy being the major producers. This activity, however, may represent a serious environmental problem due to the discharge of highly polluted effluents, usually referred to as 'olive mill wastewaters' (OMWs). They are characterized by high values of chemical oxygen demand (COD) (80-300 g/L), lipids, total polyphenols (TPP), tannins and other substances difficult to degrade. An adequate treatment before discharging is therefore required to reduce the pollutant load. The aim of the present paper was to evaluate performances of a biological process in a sequencing batch reactor (SBR) fed with pre-treated OMWs. Pre-treatment consisted of a combined acid cracking (AC) and granular activated carbon (GAC) adsorption process. The efficiency of the system was compared with that of an identical SBR fed with the raw wastewater only diluted. Combined AC and GAC adsorption was chosen to be used prior to the following biological process due to its capability of providing high removal efficiencies of COD and TPP and also appreciable improvement of biodegradability. Comparing results obtained with different influents showed that best performances of the SBR were obtained by feeding it with raw diluted OMWs (dOMWs) and at the lowest dilution ratio (1:25): in this case, the removal efficiencies were 90 and 76%, as average, for COD and TPP, respectively. Feeding the SBR with either the pre-treated or the raw dOMWs at 1:50 gave very similar values of COD reduction (74%); however, an improvement of the TPP removal was observed in the former case.

  13. Apparatus for measurement of coefficient of friction

    Science.gov (United States)

    Slifka, A. J.; Siegwarth, J. D.; Sparks, L. L.; Chaudhuri, Dilip K.

    1990-01-01

    An apparatus designed to measure the coefficient of friction in certain controlled atmospheres is described. The coefficient of friction observed during high-load tests was nearly constant, with an average value of 0.56. This value is in general agreement with that found in the literature and also with the initial friction coefficient value of 0.67 measured during self-mated friction of 440C steel in an oxygen environment.

  14. New definition of the cell diffusion coefficient

    International Nuclear Information System (INIS)

    Koehler, P.

    1975-01-01

    As was shown in a recent work by Gelbard, the usually applied Benoist definition of the cell diffusion coefficient gives two different values if two different definitions of the cell are made. A new definition is proposed that preserves the neutron balance for the homogenized lattice and that is independent of the cell definition. The resulting diffusion coefficient is identical with the main term of Benoist's diffusion coefficient

  15. Transfer coefficients in ultracold strongly coupled plasma

    Science.gov (United States)

    Bobrov, A. A.; Vorob'ev, V. S.; Zelener, B. V.

    2018-03-01

    We use both analytical and molecular dynamic methods for electron transfer coefficients in an ultracold plasma when its temperature is small and the coupling parameter characterizing the interaction of electrons and ions exceeds unity. For these conditions, we use the approach of nearest neighbor to determine the average electron (ion) diffusion coefficient and to calculate other electron transfer coefficients (viscosity and electrical and thermal conductivities). Molecular dynamics simulations produce electronic and ionic diffusion coefficients, confirming the reliability of these results. The results compare favorably with experimental and numerical data from earlier studies.

  16. Comparing linear probability model coefficients across groups

    DEFF Research Database (Denmark)

    Holm, Anders; Ejrnæs, Mette; Karlson, Kristian Bernt

    2015-01-01

    of the following three components: outcome truncation, scale parameters and distributional shape of the predictor variable. These results point to limitations in using linear probability model coefficients for group comparisons. We also provide Monte Carlo simulations and real examples to illustrate......This article offers a formal identification analysis of the problem in comparing coefficients from linear probability models between groups. We show that differences in coefficients from these models can result not only from genuine differences in effects, but also from differences in one or more...... these limitations, and we suggest a restricted approach to using linear probability model coefficients in group comparisons....

  17. Rate coefficients for hydrogen abstraction reaction of pinonaldehyde

    Indian Academy of Sciences (India)

    The H abstraction reaction from the –CHO group was found to be the most dominant reaction channelamong all the possible reaction pathways and its corresponding rate coefficient at 300 K is kEckart's unsymmetrical= 3.86 ×10-10 cm3 molecule-1 s-1. Whereas the channel with immediate lower activation energy is the ...

  18. Husimi-cactus approximation study on the diluted spin ice

    Science.gov (United States)

    Otsuka, Hiromi; Okabe, Yutaka; Nefedev, Konstantin

    2018-04-01

    We investigate dilution effects on the classical spin-ice materials such as Ho2Ti2O7 and Dy2Ti2O7 . In particular, we derive a formula of the thermodynamic quantities as functions of the temperature and a nonmagnetic ion concentration based on a Husimi-cactus approximation. We find that the formula predicts a dilution-induced crossover from the cooperative to the conventional paramagnets in a ground state, and that it also reproduces the "generalized Pauling's entropy" given by Ke et al. To verify the formula from a numerical viewpoint, we compare these results with Monte Carlo simulation calculation data, and then find good agreement for all parameter values.

  19. Mössbauer Studies of dilute Magnetic Semiconductors

    CERN Multimedia

    Gislason, H P; Debernardi, A; Dlamini, W B

    2002-01-01

    The recent discovery of (dilute) magnetic semiconductors with wide band gaps, e.g. GaN, ZnO and other oxides, having Curie temperatures, T$_{\\textrm{c}}$, well above room temperature, has prompted extraordinary experimental and theoretical efforts to understand, control and exploit this unexpected finding not least in view of the obvious potential of such materials for the fabrication of "spin-(elec)tronic" or magneto-optic devices. Ferromagnetism (FM) was achieved mostly by doping with dilute 3d transition metal impurities, notably Mn, Fe, and Co (in \\% concentrations), during growth or by subsequent ion implantation. However, it is fair to state that experimentally the conditions for the occurrence of ferro-, antiferro- or paramagnetism with these impurities are not yet controlled as generally at least two conflicting forms of magnetism or none have been reported for each system - albeit often produced by different techniques. Theory is challenged as "conventional" models seem to fail and no generally accep...

  20. Further development of IDGS: Isotope dilution gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Li, T.K.; Parker, J.L.; Kuno, Y.; Sato, S.; Kamata, M.; Akiyama, T.

    1991-01-01

    The isotope dilution gamma-ray spectrometry (IDGS) technique for determining the plutonium concentration and isotopic composition of highly radioactive spent-fuel dissolver solutions has been further developed. Both the sample preparation and the analysis have been improved. The plutonium isotopic analysis is based on high-resolution, low-energy gamma-ray spectrometry. The plutonium concentration in the dissolver solutions then is calculated from the measured isotopic differences among the spike, the dissolver solution, and the spiked dissolver solution. Plutonium concentrations and isotopic compositions of dissolver solutions analyzed from this study agree well with those obtained by traditional isotope dilution mass spectrometry (IDMS) and are consistent with the first IDGS experimental result. With the current detector efficiency, sample size, and a 100-min count time, the estimated precision is ∼0.5% for 239 Pu and 240 Pu isotopic analyses and ∼1% for the plutonium concentration analysis. 5 refs., 2 figs., 7 tabs