Viscosities and densities of binary mixtures of hexadecane with dissolved methane or carbon dioxide at temperatures from (298 to 473) K and at pressures up to 120 MPa

We report measurements of the viscosity and density of two binary mixtures comprising hexadecane with dissolved carbon dioxide or methane over the temperature range from (298.15 to 473.15) K and at pressures up to 120 MPa. The measurements were conducted at various mole fractions x of the light component as follows: x = (0, 0.0690, 0.5877, and 0.7270) for xCO2 + (1 – x)C16H34 and x = (0, 0.1013, 0.2021, 0.2976, and 0.3979) for xCH4 + (1 – x)C16H34. The viscosity and density measurements were carried out simultaneously using a bespoke vibrating-wire apparatus with a suspended sinker. With respect to the first mixture, the apparatus was operated in a relative mode and was calibrated in octane whereas, for the second mixture, the apparatus was operated in an absolute mode. To facilitate this mode of operation, the diameter of the centerless-ground tungsten wire was measured with a laser micrometer, and the mass and volume of the sinker were measured independently by hydrostatic weighing. In either mode of operation, the expanded relative uncertainties at 95% confidence were 2% for viscosity and 0.3% for density. The results were correlated using simple relations that express both density and viscosity as functions of temperature and pressure. For both pure hexadecane and each individual mixture, the results have been correlated using the modified Tait equation for density, and the Tait–Andrade equation for viscosity; both correlations described our data almost to within their estimated uncertainties. In an attempt to model the viscosity of the binary mixtures as a function of temperature, density, and composition, we have applied the extended-hard-sphere model using several mixing rules for the characteristic molar core volume. The most favorable mixing rule was found to be one based on a mole-fraction-weighted sum of the pure component molar core volumes raised to a power γ which was treated as an adjustable parameter. In this case, deviations of the experimental viscosities from the model were within ±25%

Saturated phase densities of (CO2 + H2O) at temperatures from (293 to 450) K and pressures up to 64 MPa

An apparatus consisting of an equilibrium cell connected to two vibrating tube densimeters and two syringe pumps was used to measure the saturated phase densities of (CO2 + H2O) at temperatures from (293 to 450) K and pressures up to 64 MPa, with estimated average standard uncertainties of 1.5 kg · m−3 for the CO2-rich phase and 1.0 kg · m−3 for the aqueous phase. The densimeters were housed in the same thermostat as the equilibrium cell and were calibrated in situ using pure water, CO2 and helium. Following mixing, samples of each saturated phase were displaced sequentially at constant pressure from the equilibrium cell into the vibrating tube densimeters connected to the top (CO2-rich phase) and bottom (aqueous phase) of the cell. The aqueous phase densities are predicted to within 3 kg · m−3 using empirical models for the phase compositions and partial molar volumes of each component. However, a recently developed multi-parameter equation of state (EOS) for this binary mixture, Gernert and Span [32], was found to under predict the measured aqueous phase density by up to 13 kg · m−3. The density of the CO2-rich phase was always within about 8 kg · m−3 of the density for pure CO2 at the same pressure and temperature; the differences were most positive near the critical density, and became negative at temperatures above about 373 K and pressures below about 10 MPa. For this phase, the multi-parameter EOS of Gernert and Span describes the measured densities to within 5 kg · m−3, whereas the computationally-efficient cubic EOS model of Spycher and Pruess (2010), commonly used in simulations of subsurface CO2 sequestration, deviates from the experimental data by a maximum of about 8 kg · m−3

Reusable glassware for routine cell culture—a sterile, sustainable and affordable alternative to single-use plastics

This is the final version. Available from Frontiers Media via the DOI in this record. Data availability statement: The raw data supporting the conclusions of this article will be made available by the authors, without undue reservationCell culture is a cornerstone of in vitro biological research. Whilst glassware was once commonplace in tissue culture facilities, in recent decades laboratories have moved towards a heavy reliance on single use plastics for routine procedures. Single use plastics allow for accessible, sterile, and often affordable equipment that comes at a high environmental cost. We developed a glassware preparation and cleaning process that allowed the comparison of “traditional” plastic-heavy, and adapted “sustainable,” cell culture practices, to empirically compare the sterility, viability, and proliferative capacity of cells cultured with differing techniques, by observing IL-6 production, morphology, and proliferation rate of cultured human pulmonary fibroblast cells. During which, we calculated the carbon footprint of traditional versus sustainable methods. We additionally endeavored to provide a realistic overview of the steps required to transition to more sustainable cell culture practices and make suggestions to ease the cost, labor, and time required to uptake similar practices in other laboratories. Cells cultured using reusable glassware did not show signs of contamination or stress compared to cells grown solely with plasticware, and glassware baked at 180°C for 120  min was sufficiently decontaminated and depyrogenated for culturing these cells. An individual researcher adopting the same methodology could reduce their carbon footprint by 105.92  kg of Carbon dioxide equivalent (CO2e) whilst also saving money (£408.78) over a 10-year period. We predict that these benefits would be greater if more researchers were to uptake these adapted practices. We intend for this paper to reassure researchers that viable, sterile, and sustainable routine cell culture can be achieved with little upfront cost to the researcher, with the prospective benefit of greatly reducing the cost to the environment. We additionally hope that increased uptake, and thus demand of more sustainable practices, encourages suppliers, policy makers, and funding bodies to make sustainable practices more accessible to individual researchers and institutions worldwide.University of Exete

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

Solubility and interfacial tension models for CO₂–brine systems under CO₂ geological storage conditions

Thermodynamic properties of the CO2–brine pseudo-binary system are essential for the design of geological carbon storage (GCS) projects, especially those utilizing saline aquifers. The gas–liquid–solid interactions manifest in the interfacial tensions (IFTs) and contact angle determine the injectability, sealing capacity, and storage security of the GCS process. Dissolution of CO2 in the reservoir brine occurs throughout the entire GCS process, leading to enhanced storage capacity but also to acidification of the brine, possibly leading to reservoir or seal damage. Two of the most important thermodynamic properties of the fluids are the mutual solubility and the IFT of the CO2–brine pseudo-binary system. In this work, we report a new correlative model for the IFT between CO2- and water-rich phases over wide ranges of temperature (273 to 473 K) and pressure (up to 100 MPa). The model is parameterized for brines comprising any combinations of sodium, potassium, calcium and magnesium cations with chloride, sulphate and bicarbonate anions up to a total molality of at least 5 mol·kg−1. The independent variables in this new model are reduced temperature, ion molalities and the mole fraction of CO2 dissolved in the aqueous phase. The latter is related to temperature, pressure and ion molalities by an improved model for the mutual solubility. More than 2000 experimental data points were used in the development of the two models. For the IFT of the CO2-H2O binary system, the overall root-mean-square deviation (RMSD) is 0.65 mN·m−1 while the absolute average relative deviation (AARD) is 1.8%. In the case of mutual solubility, the RMSD of CO2 mole fraction in the aqueous phase is 0.0003 and the AARD is 5.5% while, in the non-aqueous phase, the RMSD of H2O mole fraction is 0.0035 and the corresponding AARD is 8.7%. Similar results are found for the CO2-brine systems

Subaortic stenosis in the spectrum of atrioventricular septal defects Solutions may be complex and palliative

AbstractFrom July 1982 through September 1994, 19 children had operative treatment of subaortic stenosis associated with an atrioventricular septal defect. Specific diagnosis were septum primum defects in 7, Rastelli type A defects in 6, transitional defects in 4, inlet ventricular septal defect with malattached chordae in 1, and tetralogy of Fallot with Rastelli type C defect in 1. Twenty-seven operations for subaortic stenosis were performed. Surgical treatment of the outlet lesion was performed at initial atrioventricular septal defect repair in 3 children and in the remaining 16 from 1.2 to 13.1 years (mean 4.9 years, median 3.9 years) after repair. Eighteen of the 19 children had fibrous resection and myectomy for relief of obstruction. Seven children had an associated left atrioventricular valve procedure. One child received an apicoaortic conduit. Seven children (36.8%) required 8 reoperations for previously treated subaortic stenosis. Time to the second procedure was 2.8 to 7.4 years (mean 4.9 years). Follow-up is 0.4 to 14.0 years (median 5.6 years). Six-year actuarial freedom from reoperation is 66% ±15%. The angle between the plane of the outlet septum and the plane of the septal crest was measured in 10 normal hearts (86.4 ±13.7) and 10 hearts with atrioventricular septal defects (22.2 ±26.0; p <0.01). The outflow tract can be effectively shortened, widened, and the angle increased toward normal by augmenting the left side of the superior bridging leaflet and performing a fibromyectomy. Conclusion: Standard fibromyectomy for subaortic stenosis in children with atrioventricular septal defects leads to a high rate of reoperation. Leaflet augmentation and fibromyectomy may decrease the likelihood of reoperation. (J THORAC CARDIOVASC SURG 1995;110:1534-42

Speeds of sound in n-Pentane at temperatures from 233.50 to 473.15 K at pressures up to 390 MPa

We report speeds of sound in n-pentane measured using two similar apparatus, located at Ruhr University Bochum (RUB) and Imperial College London (ICL), covering different ranges of temperature and pressure. At RUB, measurements were conducted at temperatures from 233.50 to 353.20 K with pressures up to 20 MPa, while temperatures from 263.15 to 473.15 K with pressures up to 390 MPa were covered at ICL. Accounting for the uncertainties in temperature, pressure, path-length calibration, and pulse timing, the relative expanded combined uncertainty (k = 2) in the speed of sound varied from 0.015 to 0.18% over the whole region investigated. Nevertheless, small differences averaging at 0.13% are found between the two data sets in the region of overlap. The experimental data reported in this work have been partly used in the development of a new fundamental equation of state for n-pentane

An evaluation of the replacement of animal-derived biomaterials in human primary cell culture

This is the final version. Available on open access from SAGE Publications via the DOI in this record. The likelihood that potential new drugs will successfully navigate the current translational pipeline is poor, with fewer than 10% of drug candidates making this transition successfully, even after their entry into clinical trials. Prior to this stage, candidate drugs are typically evaluated by using models of increasing complexity, beginning with basic in vitro cell culture studies and progressing through to animal studies, where many of these candidates are lost due to lack of efficacy or toxicology concerns. There are many reasons for this poor translation, but interspecies differences in functional and physiological parameters undoubtedly contribute to the problem. Improving the human-relevance of early preclinical in vitro models may help translatability, especially when targeting more nuanced species-specific cell processes. The aim of the current study was to define a set of guidelines for the effective transition of human primary cells of multiple lineages to more physiologically relevant, translatable, animal-free in vitro culture conditions. Animal-derived biomaterials (ADBs) were systematically replaced with non-animal-derived alternatives in the in vitro cell culture systems, and the impact of the substitutions subsequently assessed by comparing the kinetics and phenotypes of the cultured cells. ADBs were successfully eliminated from primary human dermal fibroblast, uterine fibroblast, pulmonary fibroblast, retinal endothelial cell and peripheral blood mononuclear cell culture systems, and the individual requirements of each cell subtype were defined to ensure the successful transition toward growth under animal-free culture conditions. We demonstrate that it is possible to transition ('humanise') a diverse set of human primary cell types by following a set of simple overarching principles that inform the selection, and guide the evaluation of new, improved, human-relevant in vitro culture conditions.Animal Free Research U