Testing the neutrality of matter by acoustic means in a spherical resonator

New measurements to test the neutrality of matter by acoustic means are reported. The apparatus is based on a spherical capacitor filled with gaseous SF$_6$ excited by an oscillating electric field. The apparatus has been calibrated measuring the electric polarizability. Assuming charge conservation in the $\beta$ decay of the neutron, the experiment gives a limit of $\epsilon_\text{p-e}\lesssim1\cdot10^{-21}$ for the electron-proton charge difference, the same limit holding for the charge of the neutron. Previous measurements are critically reviewed and found incorrect: the present result is the best limit obtained with this technique

An industrial reference fluid for moderately high viscosity

In industrial practice, there is a demand for a reference standard for viscosity that is established for a readily available fluid to simplify the calibration of industrial viscometers for moderately high viscosities [(50 to 125) mPa · s]. Diisodecyl phthalate (DIDP) has been suggested as that reference fluid, and a number of studies of its properties have been carried out in several laboratories throughout the world, within the auspices of a project coordinated by the International Association for Transport Properties. That project has now progressed to the point where it is possible to collate the results of studies of the viscosity of the fluid by a number of different techniques, so as to lead to a proposed standard reference value which will be included in the paper. To support this recommended value, the various measurements conducted have been critically reviewed, and the sample purity and other factors affecting the viscosity have been studied. Density and surface tension measurements have also been performed. This paper does not describe the individual viscosity determinations carried out in independent laboratories because these are the subject of individual publications, but it does describe the ancillary studies conducted and their relevance to the viscosity standard. In addition, the paper contains recommended values for the viscosity of liquid DIDP. The samples of DIDP to which the recommended values refer are isomeric mixtures available commercially from certain suppliers, with a minimum purity by gas chromatography of 99.8 %. The recommended values result from a critical examination of all the measurements conducted to date and are supported by careful arguments dealing with the likely effects of the isomeric content of the sample as well as of other impurities. The proposed reference standard is intended particularly to serve an industrial need for a readily available calibration material with a viscosity close to that required in practical situations. To that end, the recommended value has an overall relative uncertainty of approximately 1 %. It is therefore not intended to supersede for the reference value for the viscosity of water at 20 °C, which is known much more accurately, but rather to complement it

Primary or secondary? A dichotomy of the strontium isotope anomalies in the Ediacaran carbonates of Saudi Arabia

Secular variation of 87Sr/86Sr in carbonate strata has been widely used in regional and global chemostratigraphic correlations. Typically, diagenesis results in higher 87Sr/86Sr signals relative to their primary composition due to the alteration by Rb-rich fluids and radiogenic decay of 87Rb to 87Sr. Surprisingly, 87Sr/86Sr values in the Ediacaran limestones from Saudi Arabia (from 0.7029 to 0.7059) are significantly lower than typical Ediacaran seawater values (mostly from 0.7080 to 0.7090) based on a global compilation. Understanding the origin of these anomalies is important insofar as early macrofossils are preserved in these strata. Two hypotheses have been independently evaluated in this study. The first hypothesis shows a low temperature scenario with isolated oceans or lakes in proximity to a mafic source. The second hypothesis is characterized by a high temperature scenario with profound overprints by juvenile hydrothermal fluids. Integrated Sr and Nd isotope data reveal that the 87Sr/86Sr anomalies are closely coupled with positive εNd(t = 560 Ma) values (up to +4.1). Clear covariations between 87Sr/86Sr, εNd, TOC, δ13Ccarb, δ13Corg, and δ18Ocarb were found. Based on multiple lines of petrographic, field, and geochemical evidence, the second hypothesis (i.e., hydrothermal alteration by juvenile fluids) is preferred in this study. Thermogenic breakdown of organic matter in host sediments may have caused the increasingly low TOC abundance and high δ13Corg signals of the residual organic matter. We argue that the concept that the Ediacaran biotic radiation took place in an isolated lake environment should be treated with caution. These remarkably low 87Sr/86Sr signals have neither temporal nor biogeochemical significance. Sr isotope chemostratigraphy in this particular region may not be a reliable tool for stratigraphic correlations

Impact of CO₂ impurity on CO₂ compression, liquefaction and transportation

Abstract The impurities present in carbon dioxide (CO2) streams for Carbon Capture and Storage (CCS) schemes are extremely important for CO2 pipeline and ship transportation affecting, for instance, the range of operation, safety considerations, fracture, cracking, corrosion control, dispersion in the event of a release, fluid density, operating pressure and temperature and the quantity of CO2 that can be transported. The range and levels of potential impurities present in captured CO2 from CO2 capture facilities will differ between sources and also between the capture technologies installed at the CO2 emission sources. However, the potential CO2 specifications that could enter the transport and storage systems, particularly from industrial sources, remain relatively under-researched. Consequently, the effect of these potential impurities in CO2 streams on CO2 transportation also needs to be understood. This paper summarises the main findings of an IEAGHG study, “Impact of CO2 Impurity on CO2 Compression, Liquefaction and Transportation”, commissioned to identify potential impurities and address the consequences of their impact on CO2 transportation

Improvement of Quality in Publication of Experimental Thermophysical Property Data: Challenges, Assessment Tools, Global Implementation, and Online Support

Article on the improvement of quality in the publication of experimental thermophysical property data

Extended integral-equation theories for Lennard-Jones fluids

19-29The Percus-Yervick (PY) integral-equation has been extended and used to determine structural and thermodynamic properties of a Lennard-Jones (LJ) fluid. The PY theory has been extended by calculating the coefficients, up to the thirdorder in density, of the tail function when the latter is expanded as a power series. For a LJ fluid , the resulting integralequation is exact at the level of the 5th virial coefficient. The properties obtained from the new procedure have been compared with a virial equation of state truncated after the 5th coefficient, computer simulation data and two empirical closures proposed by others. Excellent agreement has been obtained with simulation data for compression factor in the entire gas-phase region, excluding the critical region. The radial distribution function calculated from the method is in very good agreement with simulation data at supercritical temperatures and a density which is greater than the critical value by almost one-third. The tail functions which result from the approximate theories, at super-critical temperatures where data are available for comparison, compare poorly with simulation data at separations within the potential core and at long- range; there is only a fair agreement at intermediate separations at the lowest density examined