The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform
Jaroslav Patek - One of the best experts on this subject based on the ideXlab platform.
-
group contribution and parachor analysis of experimental data on density and surface tension for members of the homologous series of 1 cn 3 methylimidazolium chlorides
Fluid Phase Equilibria, 2017Co-Authors: Monika Souckova, Jaroslav Klomfar, Jaroslav PatekAbstract:Abstract The density and surface tension values are presented that represent the best current knowledge of these properties for members of the homologous series of 1-C n -3-methylimidazolium chlorides. To identify these values, a Method was used based on the consistency requirement between selected background experimental data and group contribution models of known best achievable accuracy. The models have been developed using our own and other authors' data. For this purpose 64 and 119 new experimental data on the density and surface tension, respectively, have been measured for [C 1 IM][Cl] and [C n MIM][Cl] with n = 2 , 3, 4, 6, and 10 at temperatures from (263 to 365) K and at the pressure of 0.1 MPa. The density was measured using the Buoyancy Method while the surface tension was measured by the Wilhelmy plate and du Nouy ring Method in parallel. The respective expanded combined uncertainties at the 0.95 confidence level of the resultant means of sets of individual measurements performed at a given temperature do not exceed 1 kg ⋅ m −3 , 0.07 mN ⋅ m −1 and 1 mN ⋅ m −1 . The estimated maximum deviations of the obtained recommended values from the true density and surface tension values are 0.1 kg ⋅ m −3 and 0.15 mN ⋅ m −1 , respectively.
-
surface tension and 0 1 mpa density data for 1 cn 3 methylimidazolium iodides with n 3 4 and 6 validated using a parachor and group contribution model
The Journal of Chemical Thermodynamics, 2015Co-Authors: Monika Souckova, Jaroslav Klomfar, Jaroslav PatekAbstract:Abstract Experimental data over the temperature range from (283 to 365) K are presented on the 0.1 MPa density and (air + liquid) interfacial tension for three 1- C n -3-methylimidazolium iodides with n = 3 , 4, and 6 still poorly or even not studied in these respects at all. The reported density data were obtained using a single-sinker Buoyancy Method with an estimated combined expanded uncertainty at 0.95 confidence level U c = 1.0 kg · m−3 ( 7 · 10 - 4 ϱ ). The surface tension data were obtained by the Wilhelmy plate Method with U c = 0.08 mN · m−1 and by du Nouy ring Method with U c = 0.3 mN · m−1. The Krűss K100MK2 tensiometer was used to determine the Buoyancy and surface tension forces. The density data obtained for the three studied ionic liquids match a single common group contribution model within their experimental uncertainties, which indirectly supports the data validity. Similar single common model for the surface tension data, based on the parachor, results in two times greater average absolute relative deviation of the data than provide empirical models developed for each ionic liquid separately. For the CH2 parachor group contribution a value of 32.8 (mN · m−1)1/4 mol · cm−3 was obtained, based on surface tension and density data for 33 ionic liquids at T = 298.15 K.
-
group contribution and parachor analysis of experimental data on densities and surface tension for six ionic liquids with the pf6 anion
Fluid Phase Equilibria, 2015Co-Authors: Jaroslav Klomfar, Monika Souckova, Jaroslav PatekAbstract:Abstract Experimental data over the temperature range from 268 to 365 K are presented on the 0.1 MPa density and surface tension for three 1-Cn-3-methylimidazolium hexafluorophosphates with n = 5, 7, and 9. In addition, experimental data on surface tension dependence on temperature are presented for hexafluorophosphates with [C3MIM], [C4MMIM] and [C4MPy] cation. For all of these ionic liquids there exists only sporadic data sets or they have not yet been studied at all in these two respects. The reported density data were obtained using a single-sinker Buoyancy Method. The expanded combined uncertainty at 0.95 confidence level in the density and surface tension measurements is estimated to be, respectively, from 0.3 to 0.7 kg m−3 and from 0.05 to 0.07 mN m−1. To determine the Buoyancy and surface forces, the Krűss K100MK2 tensiometer was used. A group contribution model is proposed to generate recommended values of density at 0.1 MPa for 1-Cn-3-methylimidazolium hexafluorophosphates with n = 2–9 at temperatures from 273 to 365 K. The worth-case relative error of the recommended density values is estimated to 0.1%. The homologous series of the imidazolium-based hexafluorophosphates shows statistically discernible odd-even effects in the molar volume, and in enthalpy and entropy of surface formation at the level of the order of magnitude of 10−1 cm3mol−1, 100 mJ m−2 and 10−3 mJ m−2K−1, respectively.
Monika Souckova - One of the best experts on this subject based on the ideXlab platform.
-
group contribution and parachor analysis of experimental data on density and surface tension for members of the homologous series of 1 cn 3 methylimidazolium chlorides
Fluid Phase Equilibria, 2017Co-Authors: Monika Souckova, Jaroslav Klomfar, Jaroslav PatekAbstract:Abstract The density and surface tension values are presented that represent the best current knowledge of these properties for members of the homologous series of 1-C n -3-methylimidazolium chlorides. To identify these values, a Method was used based on the consistency requirement between selected background experimental data and group contribution models of known best achievable accuracy. The models have been developed using our own and other authors' data. For this purpose 64 and 119 new experimental data on the density and surface tension, respectively, have been measured for [C 1 IM][Cl] and [C n MIM][Cl] with n = 2 , 3, 4, 6, and 10 at temperatures from (263 to 365) K and at the pressure of 0.1 MPa. The density was measured using the Buoyancy Method while the surface tension was measured by the Wilhelmy plate and du Nouy ring Method in parallel. The respective expanded combined uncertainties at the 0.95 confidence level of the resultant means of sets of individual measurements performed at a given temperature do not exceed 1 kg ⋅ m −3 , 0.07 mN ⋅ m −1 and 1 mN ⋅ m −1 . The estimated maximum deviations of the obtained recommended values from the true density and surface tension values are 0.1 kg ⋅ m −3 and 0.15 mN ⋅ m −1 , respectively.
-
surface tension and 0 1 mpa density data for 1 cn 3 methylimidazolium iodides with n 3 4 and 6 validated using a parachor and group contribution model
The Journal of Chemical Thermodynamics, 2015Co-Authors: Monika Souckova, Jaroslav Klomfar, Jaroslav PatekAbstract:Abstract Experimental data over the temperature range from (283 to 365) K are presented on the 0.1 MPa density and (air + liquid) interfacial tension for three 1- C n -3-methylimidazolium iodides with n = 3 , 4, and 6 still poorly or even not studied in these respects at all. The reported density data were obtained using a single-sinker Buoyancy Method with an estimated combined expanded uncertainty at 0.95 confidence level U c = 1.0 kg · m−3 ( 7 · 10 - 4 ϱ ). The surface tension data were obtained by the Wilhelmy plate Method with U c = 0.08 mN · m−1 and by du Nouy ring Method with U c = 0.3 mN · m−1. The Krűss K100MK2 tensiometer was used to determine the Buoyancy and surface tension forces. The density data obtained for the three studied ionic liquids match a single common group contribution model within their experimental uncertainties, which indirectly supports the data validity. Similar single common model for the surface tension data, based on the parachor, results in two times greater average absolute relative deviation of the data than provide empirical models developed for each ionic liquid separately. For the CH2 parachor group contribution a value of 32.8 (mN · m−1)1/4 mol · cm−3 was obtained, based on surface tension and density data for 33 ionic liquids at T = 298.15 K.
-
group contribution and parachor analysis of experimental data on densities and surface tension for six ionic liquids with the pf6 anion
Fluid Phase Equilibria, 2015Co-Authors: Jaroslav Klomfar, Monika Souckova, Jaroslav PatekAbstract:Abstract Experimental data over the temperature range from 268 to 365 K are presented on the 0.1 MPa density and surface tension for three 1-Cn-3-methylimidazolium hexafluorophosphates with n = 5, 7, and 9. In addition, experimental data on surface tension dependence on temperature are presented for hexafluorophosphates with [C3MIM], [C4MMIM] and [C4MPy] cation. For all of these ionic liquids there exists only sporadic data sets or they have not yet been studied at all in these two respects. The reported density data were obtained using a single-sinker Buoyancy Method. The expanded combined uncertainty at 0.95 confidence level in the density and surface tension measurements is estimated to be, respectively, from 0.3 to 0.7 kg m−3 and from 0.05 to 0.07 mN m−1. To determine the Buoyancy and surface forces, the Krűss K100MK2 tensiometer was used. A group contribution model is proposed to generate recommended values of density at 0.1 MPa for 1-Cn-3-methylimidazolium hexafluorophosphates with n = 2–9 at temperatures from 273 to 365 K. The worth-case relative error of the recommended density values is estimated to 0.1%. The homologous series of the imidazolium-based hexafluorophosphates shows statistically discernible odd-even effects in the molar volume, and in enthalpy and entropy of surface formation at the level of the order of magnitude of 10−1 cm3mol−1, 100 mJ m−2 and 10−3 mJ m−2K−1, respectively.
Jaroslav Klomfar - One of the best experts on this subject based on the ideXlab platform.
-
group contribution and parachor analysis of experimental data on density and surface tension for members of the homologous series of 1 cn 3 methylimidazolium chlorides
Fluid Phase Equilibria, 2017Co-Authors: Monika Souckova, Jaroslav Klomfar, Jaroslav PatekAbstract:Abstract The density and surface tension values are presented that represent the best current knowledge of these properties for members of the homologous series of 1-C n -3-methylimidazolium chlorides. To identify these values, a Method was used based on the consistency requirement between selected background experimental data and group contribution models of known best achievable accuracy. The models have been developed using our own and other authors' data. For this purpose 64 and 119 new experimental data on the density and surface tension, respectively, have been measured for [C 1 IM][Cl] and [C n MIM][Cl] with n = 2 , 3, 4, 6, and 10 at temperatures from (263 to 365) K and at the pressure of 0.1 MPa. The density was measured using the Buoyancy Method while the surface tension was measured by the Wilhelmy plate and du Nouy ring Method in parallel. The respective expanded combined uncertainties at the 0.95 confidence level of the resultant means of sets of individual measurements performed at a given temperature do not exceed 1 kg ⋅ m −3 , 0.07 mN ⋅ m −1 and 1 mN ⋅ m −1 . The estimated maximum deviations of the obtained recommended values from the true density and surface tension values are 0.1 kg ⋅ m −3 and 0.15 mN ⋅ m −1 , respectively.
-
surface tension and 0 1 mpa density data for 1 cn 3 methylimidazolium iodides with n 3 4 and 6 validated using a parachor and group contribution model
The Journal of Chemical Thermodynamics, 2015Co-Authors: Monika Souckova, Jaroslav Klomfar, Jaroslav PatekAbstract:Abstract Experimental data over the temperature range from (283 to 365) K are presented on the 0.1 MPa density and (air + liquid) interfacial tension for three 1- C n -3-methylimidazolium iodides with n = 3 , 4, and 6 still poorly or even not studied in these respects at all. The reported density data were obtained using a single-sinker Buoyancy Method with an estimated combined expanded uncertainty at 0.95 confidence level U c = 1.0 kg · m−3 ( 7 · 10 - 4 ϱ ). The surface tension data were obtained by the Wilhelmy plate Method with U c = 0.08 mN · m−1 and by du Nouy ring Method with U c = 0.3 mN · m−1. The Krűss K100MK2 tensiometer was used to determine the Buoyancy and surface tension forces. The density data obtained for the three studied ionic liquids match a single common group contribution model within their experimental uncertainties, which indirectly supports the data validity. Similar single common model for the surface tension data, based on the parachor, results in two times greater average absolute relative deviation of the data than provide empirical models developed for each ionic liquid separately. For the CH2 parachor group contribution a value of 32.8 (mN · m−1)1/4 mol · cm−3 was obtained, based on surface tension and density data for 33 ionic liquids at T = 298.15 K.
-
group contribution and parachor analysis of experimental data on densities and surface tension for six ionic liquids with the pf6 anion
Fluid Phase Equilibria, 2015Co-Authors: Jaroslav Klomfar, Monika Souckova, Jaroslav PatekAbstract:Abstract Experimental data over the temperature range from 268 to 365 K are presented on the 0.1 MPa density and surface tension for three 1-Cn-3-methylimidazolium hexafluorophosphates with n = 5, 7, and 9. In addition, experimental data on surface tension dependence on temperature are presented for hexafluorophosphates with [C3MIM], [C4MMIM] and [C4MPy] cation. For all of these ionic liquids there exists only sporadic data sets or they have not yet been studied at all in these two respects. The reported density data were obtained using a single-sinker Buoyancy Method. The expanded combined uncertainty at 0.95 confidence level in the density and surface tension measurements is estimated to be, respectively, from 0.3 to 0.7 kg m−3 and from 0.05 to 0.07 mN m−1. To determine the Buoyancy and surface forces, the Krűss K100MK2 tensiometer was used. A group contribution model is proposed to generate recommended values of density at 0.1 MPa for 1-Cn-3-methylimidazolium hexafluorophosphates with n = 2–9 at temperatures from 273 to 365 K. The worth-case relative error of the recommended density values is estimated to 0.1%. The homologous series of the imidazolium-based hexafluorophosphates shows statistically discernible odd-even effects in the molar volume, and in enthalpy and entropy of surface formation at the level of the order of magnitude of 10−1 cm3mol−1, 100 mJ m−2 and 10−3 mJ m−2K−1, respectively.
-
Low Temperature Densities from (218 to 364) K and up to 50 MPa in Pressure and Surface Tension for Trihexyl(tetradecyl)phosphonium Bis(trifluoromethylsulfonyl)imide and Dicyanamide and 1‑Hexyl-3-methylimidazolium Hexafluorophosphate
2014Co-Authors: Jaroslav Klomfar, Monika Součková, Jaroslav PátekAbstract:Experimental p-ρ-T data obtained with a constant volume apparatus are reported for two ionic liquids with trihexyl(tetradecyl)phosphonium ([THTDP]) cation and bis(trifluoromethylsulfonyl)imide, [NTf2], and dicyanamide, [DCA], anion and for 1-hexyl-3-methylimidazolium hexafluorophosphate, [C6MIM][PF6]. The measurements were conducted at temperatures from (218 to 364) K and at nominal pressures of 1 MPa and from (10 to 50) MPa with a 10 MPa step. Thus, the temperature region covered with experimental p-ρ-T data has been substantially extended to lower temperatures for all three substances. The expanded combined uncertainty at the 0.95 confidence level of the reported densities takes its maximum value at the lower end of the temperature interval of the data, namely 1.3 kg·m–3 (1.3·10–3ρ) for [THTDP][NTf2], 0.6 kg·m–3 (0.7·10–3ρ) for [THTDP][DCA], and 1.8 kg·m–3 (1.4·10–3ρ) for [C6MIM][PF6]. The studied ionic liquids show a specific type of the temperature and pressure dependence of their internal pressure, different from that of molecular liquids such as water or aliphatic alcohols. In addition, experimental 0.1 MPa density data and air–liquid surface tension data are reported for both phosphonium based ionic liquids obtained with the Buoyancy Method and the Wilhelmy plate Method, respectively, at temperatures from (263 to 365) K
Adam Shaw - One of the best experts on this subject based on the ideXlab platform.
-
a Buoyancy Method for the measurement of total ultrasound power generated by hifu transducers
Ultrasound in Medicine and Biology, 2008Co-Authors: Adam ShawAbstract:Abstract Total acoustic output power is a key parameter for most ultrasonic medical equipment and especially for high intensity focused ultrasound (HIFU) systems, which treat certain cancers and other conditions by the noninvasive thermal ablation of the affected tissue. In planar unfocused fields, the use of a radiation force balance has been considered the most accurate Method of measuring ultrasound power. However, radiation force is not strictly dependent on the ultrasound power but, rather, on the wave momentum resolved in one direction. Consequently, measurements based on radiation force become progressively less accurate as the ultrasound wave deviates further from a true plane-wave. HIFU transducers can be very strongly focused with F-numbers less than one: under these conditions, the uncertainty associated with use of the radiation force Method becomes very significant. In this article, a new Method for determining power is described in detail. Instead of radiation force, the new Method relies on measuring the change in Buoyancy caused by thermal expansion of castor oil inside a target suspended in a water bath. The change in volume is proportional to the incident energy and is independent of focusing or the angle of incidence of the ultrasound. The principles and theory behind the new Method are laid out and the characteristics and construction of an appropriate target are examined and the results of validation tests are presented. The uncertainties of the Method are calculated to be approximately ±3.4% in the current implementation, with the potential to reduce these further. The new technique has several important advantages over the radiation force Method and offers the potential to be an alternative primary standard Method. (E-mail: adam.shaw@npl.co.uk )
Donald B Dingwell - One of the best experts on this subject based on the ideXlab platform.
-
temperature independent thermal expansivities of calcium aluminosilicate melts between 1150 and 1973 k in the system anorthite wollastonite gehlenite an wo geh a density model
Geochimica et Cosmochimica Acta, 2006Co-Authors: Marcel Potuzak, Mette Solvang, Donald B DingwellAbstract:The thermal expansivities of 10 compositions from within the anorthite–wollastonite–gehlenite (An–Wo–Geh) compatibility triangle have been investigated using a combination of calorimetry and dilatometry on the glassy and liquid samples. The volumes at room temperature were derived from densities measured using the Archimedean Buoyancy Method. For each sample, density was measured at 298 K using glass that had a cooling-heating history of 10–10 K min−1. The thermal expansion coefficient of the glass from 298 K to the glass transition interval was measured by a dilatometer and the heat capacity was measured using a differential scanning calorimeter from 298 to 1135 K. The thermal expansion coefficient and the heat flow were determined at a heating rate of 10 K min−1 on glasses which were previously cooled at 10 K min−1. Supercooled liquid density, molar volume and molar thermal expansivities were indirectly determined by combining differential scanning calorimetric and dilatometric measurements assuming that the kinetics of enthalpy and shear relaxation are equivalent. The data obtained on supercooled liquids were compared to high-temperature predictions from the models of (Lange, R.A., Carmichael, I.S.E., 1987. Densities of Na2O–K2O–CaO–MgO–FeO–Fe2O3–Al2O3–TiO2–SiO2 liquids: New measurements and derived partial molar properties. Geochim. Cosmochim. Acta51, 2931–2946; Courtial, P., Dingwell, D.B., 1995. Nonlinear composition dependence of molar volume of melts in the CaO–Al2O3–SiO2 system. Geochim. Cosmochim. Acta59 (18), 3685–3695; Lange, R.A., 1997. A revised model for the density and thermal expansivity of K2O–Na2O–CaO–MgO–Al2O3–SiO2 liquids from 700 to 1900 K: extension to crustal magmatic temperatures. Contrib. Mineral. Petrol.130, 1–11). The best linear fit combines the supercooled liquid data presented in this study and the high temperature data calculated using the Courtial and Dingwell (1995) model. This dilatometric/calorimetric Method of determining supercooled liquid molar thermal expansivity greatly increases the temperature range accessible for thermal expansion. It represents a substantial increase in precision and understanding of the thermodynamics of calcium aluminosilicate melts. This enhanced precision demonstrates clearly the temperature independence of the melt expansions in the An–Wo–Geh system. This contrasts strongly with observations for neighboring system such as anorthite–diopside and raises the question of the compositional/structural origins of temperature dependence of thermal expansivity in multicomponent silicate melts.
