Bayesian estimate of the degree of a polynomial given a noisy data sample

A widely used method to create a continuous representation of a discrete data-set is regression analysis. When the regression model is not based on a mathematical description of the physics underlying the data, heuristic techniques play a crucial role and the model choice can have a significant impact on the result. In this paper, the problem of identifying the most appropriate model is formulated and solved in terms of Bayesian selection. Besides, probability calculus is the best way to choose among different alternatives. The results obtained are applied to the case of both univariate and bivariate polynomials used as trial solutions of systems of thermodynamic partial differential equations.Comment: 10 pages, 5 figures, submitted to Metrologi

Speed of sound measurements of two binary natural gas mixtures (methane plus n-butane and methane plus isopentane) at cryogenic temperatures and in liquid phase

This paper presents accurate speed of sound measurements in two specific single-phase liquefied natural gas mixtures (methane + isopentane and methane +n-butane) for temperatures ranging from (100 to 160) K and pressures up to 12 MPa, with expanded relative uncertainties (k = 2) between (0.27 and 0.35) % for methane + n-butane and between (0.26 and 0.30) % for the methane + isopentane. These measurements have been obtained using the double pulse-echo technique. The experimental results of these measurements were compared with the values predicted by the GERG-2008 model and the most recent fundamental equation of state for the calculation of thermodynamic properties of liquefied natural gases, EOS-LNG

Speed of sound measurements in deuterium oxide (D 2 O) at temperatures between (276.97 and 363.15) K and at pressures up to 210 MPa

partially_open3embargoed_20211119Lago Simona, Giuliano Albo Paolo Alberto, Cavuoto GiuseppeLago, Simona; GIULIANO ALBO, PAOLO ALBERTO; Cavuoto, Giusepp

Speed of sound measurements in deuterium oxide (D2O) at temperatures between (276.97 and 363.15) K and at pressures up to 210 MPa

This paper presents speed of sound measurements in heavy water (deuterium oxide, ) along six isotherms between 276.97 K and 363.15 K for pressures up to 210 MPa using a double pulse-echo method. The experimental apparatus was validated measuring the speed of sound in ordinary water at ambient pressure and at temperatures between 295.5 K and 363.15 K with results found in agreement with values calculated from the reference equation of state for water by Wagner and Pruß within 0.005%. The relative combined expanded uncertainty of our speed of sound measurements, at a confidence level of 95%, is estimated to be less than 0.03% for pressures up to 10 MPa and in the order of 0.05% for pressures up to 210 MPa in the whole investigated temperature range. The speed of sound results have been compared with values calculated from the reference equation for heavy water the IAPS84 Formulation by Hill et al. (1982), and with the prediction of the newly developed equation of state for heavy water by Herrig et al. (2018). The relative deviations of these comparison were found to be consistent with the reference equations within their combined uncertainty. The results presented here were also compared with the most recent data by Wegge et al. and found to be in agreement within 0.05%

Assessing of Geochemistry and nitrate isotopes in the unconfined aquifer of a plain with agricultural activities, Córdoba, Argentina

Los fertilizantes y residuos ganaderos pueden llegar a contaminar los acuíferos con nitratos. En estos escenarios se pueden analizar los isótopos 15N y 18O del mismo como herramienta para discriminar dichas fuentes. El objetivo es identificar el origen de la contaminación a través de características geoquímicas del agua y del uso de los isótopos del nitrato en una cuenca de llanura del Sur de Córdoba, Argentina. Los valores de nitratos hallados (3,0 a 193,0 mg/L), superan en su mayoría el valor característico de fondo natural de la zona (7,5 mg/L), lo cual, sumado al aporte de otros iones detectados, evidencia la contaminación del acuífero. Los valores isotópicos de muestras seleccionadas dieron δ 15N de +6,4‰ a +12,3‰ y δ 18O de +2,0‰ a +8,0‰. Los nitratos habrían sufrido enriquecimiento isotópico principalmente por desnitrificación (verificada por εN/εO de 1,5) y volatilización en el suelo previo a su arribo al acuífero, que los desplaza de los campos asignados para cada fuente y que dificulta su discriminación. La fuente de nitratos con mejor evidencia fue la contaminación puntual de origen ganadero, si bien se sumó además la evidencia de otros indicadores y bacterias Escherichia coli.Fertilizers and livestock wastes can contaminate groundwater with nitrates. It is possible to use nitrate isotopes (15N and 18O) as a tool to discriminate different nitrate sources. The objective of this work was to identify contamination sources using water geochemical characteristics and nitrate stable isotopes in a drainage basin in the South of Cordoba province, Argentina. The observed nitrate concentration in 23 samples ranged from 3.0 to 193.0 mg/L, most exceeding the local natural background (7.5 mg/L) indicating pollution of the aquifer in addition to the contribution of other ions. The isotopic values of selected samples ranged from +6.4 ‰ to +12.3 ‰ for δ 15N and from +2.0 ‰ to +8.0 ‰ for δ 18O. Nitrate isotope enrichment mainly caused by denitrification (verified with εN/εO = 1.5) and volatilization processes in the soil, before nitrates arrive to the aquifer, shifted the isotope values out from the designated fields for each source, making difficult their discrimination. The nitrates supply which shows best evidences was the punctual pollution from livestock sources, although there were other indicators like chemical variables and Escherichia coli bacteria.Fil: Giuliano Albo, María Jesica. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Geología; ArgentinaFil: Blarasin, Mónica Teresa. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Geología; ArgentinaFil: Panarello, Hector Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotopica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotopica; Argentin

High-Pressure Speed of Sound Measurements of trans-1-Chloro-3,3,3-trifluoropropene (R1233zd(E)) in Liquid Region for Temperature from (273.15 to 353.15) K

This paper presents speed of sound measurements of liquid trans-1-chloro-3,3,3-trifluoropropene (R1233zd­(E)) along six isotherms over the temperature range from (273.15 to 353.15) K for pressures up to 35 MPa by means of the double pulse–echo method. The expanded uncertainty of the speed of sound measurements at a confidence level of 95% is 0.1%. The experimental results were compared with predictions from the state-of-the-art Fundamental Helmholtz Energy equation of state [Mondéjar, M.E.; McLinden, M.O.; Lemmon, E.W., Thermodynamic Properties of trans-1-Chloro-3,3,3-trifluoropropene (R1233zd­(E)): Vapor Pressure, (p,ρ,T) Behavior, and Speed of Sound Measurements, and Equation of State. J. Chem. Eng. Data, 2015, 60, 2477–2489]

Temperature Increase Dependence on Ultrasound Attenuation Coefficient in Innovative Tissue-mimicking Materials

Although high intensity focused ultrasound beams (HIFU) have found rapid agreement in clinical environment as a tool for non invasive surgical ablation and controlled destruction of cancer cells, some aspects related to the interaction of ultrasonic waves with tissues, such as the conversion of acoustic energy into heat, are not thoroughly understood. In this work, innovative tissue- mimicking materials (TMMs), based on Agar and zinc acetate, have been used to conduct investigations in order to determine a relation between the sample attenuation coefficient and its temperature increase measured in the focus region when exposed to an HIFU beam. An empirical relation has been deduced establishing useful basis for further processes of validations of numerical models to be adopted for customizing therapeutic treatments

Genetic diversity of Escherichia coli isolates from surface water and groundwater in a rural environment

The genetic characteristics among Escherichia coli strains can be grouped by origin of isolation. Then, it is possible to use the genotypes as a tool to determine the source of water contamination. The aim of this study was to define water aptitude for human consumption in a rural basin and to assess the diversity of E. coli water populations. Thus, it was possible to identify the main sources of fecal contamination and to explore linkages with the hydrogeological environment and land uses. The bacteriological analysis showed that more than 50% of samples were unfit for human consumption. DNA fingerprinting analysis by BOX-PCR indicated low genotypic diversity of E. coli isolates taken from surface water and groundwater. The results suggested the presence of a dominant source of fecal contamination. The relationship between low genotypic diversity and land use would prove that water contamination comes from livestock. The genetic diversity of E. coli isolated from surface water was less than that identified in groundwater because of the different hydraulic features of both environments. Furthermore, each one of the two big strain groups identified in this basin is located in different sub-basins, showing that hydrological dynamics exerts selective pressure on bacteria DNA.Fil: Gambero, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Blarasin, Mónica Teresa. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Geologia. Cat.de Hidrogeologia; ArgentinaFil: Bettera, Susana Gertrudis. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Giuliano Albo, María Jesica. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Geologia. Cat.de Hidrogeologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Geoquímica e isótopos del nitrato en el acuífero libre de un agroecosistema, cuenca del arroyo Knutzen, Córdoba, Argentina

Los fertilizantes y residuos ganaderos contaminan los acuíferos con nitratos (NO3-). En estos escenarios se pueden analizar los isótopos 15N y 18O del mismo como herramienta para discriminar dichas fuentes. El objetivo es identificar el origen de la contaminación a través de características geoquímicas del agua y del uso de los isótopos del NO3- en esta cuenca de llanura del Sur de Córdoba. Los valores de NO3- hallados (3,0 a 192,5 mg/L), superan en su mayoría el valor característico de fondo natural de la zona (7,5 mg/L), y sumado al aporte de otros iones detectados, se evidencia la contaminación del acuífero. Los valores isotópicos de muestras seleccionadas dieron δ15N de +6,39‰ a +12,33‰ y δ18O de +2,04‰ a +7,96‰. Los NO3- habrían sufrido enriquecimiento isotópico principalmente por desnitrificación (verificada por εN/εO de 1,5), que los desplaza de los campos asignados para cada fuente y que dificulta su discriminación.Fertilizers and livestock wastes contaminate groundwater with nitrates (NO3-). It is possible to use NO3 isotopes (15N and 18O) as a tool to discriminate different NO3- sources. The objective of this work is to identify contamination sources using water geochemical characteristics and nitrate stable isotopes in a drainage basin in the South of Cordoba province, Argentina. The observed NO3- concentration in 23 samples ranged from 3.0 to 192.5 mg/L, most exceeding the reference values of local natural background (7.5 mg/L) indicating pollution of the aquifer in addition to the contribution of other ions. The isotopic values of selected samples ranged from +6.39 ‰ to +12.33 ‰ for δ15N and from +2.04 ‰ to +7.96 ‰ for δ18O. NO3- isotope enrichment mainly caused by denitrification processes (verified with εN/εO = 1.5) shifted the isotope values out from the designated fields for each source, making difficult their discrimination.Universidad Nacional de La Plat