The effect of dissolved air and natural isotopic distributions on the density of water

The effects of dissolved air and of natural isotopic distributions on the density of water have been determined at 1 atm by using a magnetic float densimeter. Dissolved gases were found to decrease the density by 3.0 ± 0.2 × 10-6 g cm-3 at 4°C. The apparent molal volumes of air were found to be nearly independent of saturation concentration and temperatures between 0° and 30°C...

The equation of state of seawater determined from sound speeds

The PVT properties of seawater were calculated from the sound speed data of Chen and Millero (1977d) over the range of 0 to 40%. salinity, 0 to 40°C, and 0 to 1000 bars…

The effect of pressure on the thermodynamic properties of seawater

For many thermodynamic calculations in oceanography it is necessary to know the effect of pressure (or depth) on various thermodynamic properties. … Recently, a new equation of state for sea-water (Millero et al., 1980; Millero and Poisson, 1981) has been adopted by the UNESCO/ICES/IAPSO joint panel on oceanographic tables and standards. By appropriate differentiation of this equation of state, it is possible to determine the pressure derivatives for the specific volume of seawater solutions. To estimate the effect of pressure on the partial molal thermochemical properties (Millero and Leung, 1976), it is necessary to know the partial molal volumes of sea salt and water as a function of pressure. This can be accomplished by fitting the apparent molal volumes (c{\u3e,,) of seawater solutions to a function of pressure..

A closer look at arrested spinodal decomposition in protein solutions

Concentrated aqueous solutions of the protein lysozyme undergo a liquid solid transition upon a temperature quench into the unstable spinodal region below a characteristic arrest temperature of Tf=15C. We use video microscopy and ultra-small angle light scattering in order to investigate the arrested structures as a function of initial concentration, quench temperature and rate of the temperature quench. We find that the solid-like samples show all the features of a bicontinuous network that is formed through an arrested spinodal decomposition process. We determine the correlation length Xi and demonstrate that Xi exhibits a temperature dependence that closely follows the critical scaling expected for density fluctuations during the early stages of spinodal decomposition. These findings are in agreement with an arrest scenario based on a state diagram where the arrest or gel line extends far into the unstable region below the spinodal line. Arrest then occurs when during the early stage of spinodal decomposition the volume fraction phi2 of the dense phase intersects the dynamical arrest threshold phi2Glass, upon which phase separation gets pinned into a space-spanning gel network with a characteristic length Xi

The density of seawater solutions at one atmosphere as a function of temperature and salinity

The relative density (d – d0) of diluted and evaporated standard seawater solutions have been determined at one atmosphere with a magnetic float densimeter and a suspension balance from 0.5 to 40‰ salinity and 0 to 40°C…

The equation of state of seawater

The P-V-T properties of seawater calculated from the sound derived equation of state of Wang and Millero (1973)

History of the Equation of State of Seawater

As one of few who have been involved in the equation of state of seawater over the last 40 years, the author was invited to review some of the history behind its early development and also the more recent thermodynamic equation of state. The article first reviews early (late 1800s) work by Knudsen and others in defining the concept of salinity. This summary leads into the development of the practical salinity scale. Our studies at the University of Miami Rosenstiel School, along with the work of Alain Poisson’s group at Laboratoire de Physique et Chimie, Université Pierre et Marie Curie and that of Alvin Bradshaw and Karl Schleicher at Woods Hole Oceanographic Institution, were instrumental in deriving the 1980 equation of state (EOS-80) that has been used for 30 years. The fundamental work of Ranier Feistel at Leibniz Institute for Baltic Sea Research led to the development of a Gibbs free energy function that is the backbone of the new thermodynamic equation of state (TEOS-10). It can be used to determine all of the thermodynamic properties of seawater. The salinity input to the TEOS-10 Gibbs function requires knowledge of the absolute salinity of seawater (SA), which is based upon the reference salinity of seawater (SR). The reference salinity is our best estimate of the absolute salinity of the seawater that was used to develop the practical salinity scale (SP), the equation of state, and the other thermodynamic properties of seawater. Reference salinity is related to practical salinity by SR = SP (35.16504/35.000) g kg-1 and absolute salinity is related to reference salinity by SA = SR + δSA,where δSA is due to the added solutes in seawater in deep waters resulting from the dissolution of CaCO3(s) and SiO2(s), CO2, and nutrients like NO3 and PO4 from the oxidation of plant material. The δSA values due to the added solutes are estimated from the differences between the measured densities of seawater samples compared with the densities calculated from the TEOS-10 equation of state (Δρ) at the same reference salinity, temperature, and pressure, using δSA = Δρ/0.75179 g kg-1.The values of δSA in the ocean can be estimated for waters at given longitude, latitude, and depth using correlations of δSA and the concentration of Si(OH)4 in the waters. The SA values can then be used to calculate all the thermodynamic properties of seawater in the major oceans using the new TEOS-10. It will be very useful to modelers examining the entropy and enthalpy of seawater

Seasonal variations in the aragonite saturation state in the upper open-ocean waters of the North Pacific Ocean

Seasonal variability of the aragonite saturation state ((AR)) in the upper (50m and 100m depths) North Pacific Ocean (NPO) was investigated using multiple linear regression (MLR). The MLR algorithm derived from a high-quality carbon data set accurately predicted the (AR) of evaluation data sets (three time series stations and P02 section) with acceptable uncertainty (<0.1(AR)). The algorithm was combined with seasonal climatology data, and the estimated (AR) varied in the range of 0.4-0.6 in the midlatitude western NPO, with the largest variation found for the tropical eastern NPO. These marked variations were largely controlled by seasonal changes in vertical mixing and thermocline depth, both of which determine the degree of entrainment of CO2-rich corrosive waters from deeper depths. Our MLR-based subsurface (AR) climatology is complementary to surface climatology based on pCO(2) measurements.1184Ysciescopu

A global algorithm for estimating Absolute Salinity

The International Thermodynamic Equation of Seawater – 2010 has defined the thermodynamic properties of seawater in terms of a new salinity variable, Absolute Salinity, which takes into account the spatial variation of the composition of seawater. Absolute Salinity more accurately reflects the effects of the dissolved material in seawater on the thermodynamic properties (particularly density) than does Practical Salinity. &lt;br&gt;&lt;br&gt; When a seawater sample has standard composition (i.e. the ratios of the constituents of sea salt are the same as those of surface water of the North Atlantic), Practical Salinity can be used to accurately evaluate the thermodynamic properties of seawater. When seawater is not of standard composition, Practical Salinity alone is not sufficient and the Absolute Salinity Anomaly needs to be estimated; this anomaly is as large as 0.025 g kg&lt;sup&gt;−1&lt;/sup&gt; in the northernmost North Pacific. Here we provide an algorithm for estimating Absolute Salinity Anomaly for any location (&lt;i&gt;x, y, p&lt;/i&gt;) in the world ocean. &lt;br&gt;&lt;br&gt; To develop this algorithm, we used the Absolute Salinity Anomaly that is found by comparing the density calculated from Practical Salinity to the density measured in the laboratory. These estimates of Absolute Salinity Anomaly however are limited to the number of available observations (namely 811). In order to provide a practical method that can be used at any location in the world ocean, we take advantage of approximate relationships between Absolute Salinity Anomaly and silicate concentrations (which are available globally)

Zeta potential in intact natural sandstones at elevated temperatures

Supporting data are included in PDF and CSV files; any additional data may be obtained from the corresponding author (e-mail: [email protected]). TOTAL is thanked for partial support of Jackson's Chair in Geological Fluid Mechanics and for supporting the activities of the TOTAL Laboratory for Reservoir Physics at Imperial College London where these experiments were conducted. The Editor thanks Andre Revil and Paul Glover for their assistance in evaluating this paper.Peer reviewedPublisher PD