Saturated Volume Research Articles

Cyclic shear strength of a loose glacial till

The liquefaction potential of a loose glacial till is assessed by laboratory cyclic tests and by comparison with test results obtained on a clean sand, using the same testing procedures. The laboratory testing program of both soils included cyclic triaxial tests on saturated specimens and constant volume cyclic simple shear tests on dry specimens. The till and the sand exhibited very similar behaviour during cycling and mobilized nearly identical cyclic shear strengths in the triaxial as well as in the simple shear tests. The 28% fines content in the till did not make it more resistant to liquefaction than a clean sand. Key words: liquefaction, sand, silty sand, cyclic simple shear test, cyclic triaxial test.

A new three-parameter cubic equation of state for polar fluids and fluid mixtures

Abstract A simple cubic equation of state of the van der Waals type is developed for simultaneous representation of vapor-liquid equilibrium and saturated liquid and vapor volumes for polar fluids and fluid mixtures. The new equation consists of three parameters and only the parameter > lda” is made temperature dependent. A new and generalized expression is developed for the temperature dependence of the parameter. The new equation yields good representation for pure components. For mixtures the new equation is as capable for VLE calculations as the Soave-Redlich-Kwong, the Peng-Robinson and the Patel-Teja equations, but it yields lower deviations in the predicted saturated liquid volumes.

Vapor - liquid equilibria with the vdW - 711 equation of state

It is demonstrated that the vdW - 711 equation of state (EoS) provides successful correlation and prediction of (i) vapor - liquid equilibria, (ii) saturated liquid volumes, and (iii) enthalpy departures for non-polar/weakly polar systems. It thus represents, the simplest cubic equation of state to accomplish all these three objectives.

Phase equilibria for four binary systems containing propylene

Isothermal vapor—liquid equilibria (P−x, y) for four binary systems of propylene with methanol, acetone, diethyl ether and propylene oxide were measured using a swing method at 25°C. Also, the saturated molar volume of the liquid phase for each system was obtained by a weighing method. The data obtained were correlated by use of the Soave-Redlich-Wong equation. The P-x, y relations were described satisfactorily, except for the methanol—propylene

A simple and accurate technique to obtain pure component parameters for three-parameter equations of state

Abstract A generalized technique is presented for the calculation of the pure component parameters for the three-parameter equation of state. For illustration, the Usdin-McAuliffe form of cubic equation of state is evaluated. The method requires as input data the vapor pressure and saturated liquid volume of a component at a given temperature. This method may be considered as an extension of Panagiotopoulos-Kumar's method.

PORE VOLUME CHANGES IN A STRUCTURED SILT-LOAM SOIL DURING DRYING

Shrinkage and volumetric water content of undisturbed soil cores 150 mm diam. × 100 mm high from four horizons of a silt-loam, Orthic Humic Gleysol were monitored throughout a drying cycle from saturation to oven dryness. Drying from saturation to − 100 kPa was by desorption apparatus. Subsequently the cores were subjected to controlled air drying and finally oven drying. The volume change, relative to the volume at saturation, of each core was monitored at 20 different water contents on the desorption curve, by measuring the X, Y and Z positions of 92 pins inserted in the top of each core. Total shrinkage values expressed as percentages of the cores' saturated volumes were Ap −23.4%, Bg −7.0%, BCg −11.8% and Cg −12.9%. The influence of soil structure on soil shrinkage was analyzed and the results were inconclusive because there appeared to be a complex interaction between ped size and the scale of measurement for shrinkage. Water loss during drying was partitioned between that replaced by air and that associated with pore volume reduction. For the Ap horizon from 0 to 1500 kPa, the proportions were 62% and 38% respectively. The results show clearly the dependence of soil bulk density and porosity on water potential and reinforce the contention that for comparison purposes bulk density and porosity must be expressed at a reference water content or potential. Key words: Shrinkage, pore volume, bulk density, undisturbed samples

Relative volatilities from mixture liquid densities for the n-butane/1,3-butadiene system

Abstract Experimental compressed liquid densities for n-butane/1,3-butadiene mixtures are reported and have been used to calculate relative volatilities. These calculated values agree with literature values to within 2% and effectively characterize the mixture interaction. To perform the calculations, we first used pure-component saturated liquid and vapor volumes, and vapor pressures to determine three pure-component parameters in the Peneloux—Soave equation of state. The compressed liquid densities for the mixtures were linearly extrapolated to the bubble point pressure of the mixture, and these saturated liquid volumes were used to evaluate a single binary interaction parameter.

Thermodynamics of associating component + saturated hydrocarbon mixtures at low pressures. I. Description of saturated vapour pressures and liquid molar volumes of pure n-alcohols in terms of association

A new approach, based on the homomorph concept and taking into account equation of state effects, to correlate saturated vapour pressures and liquid molar volumes of pure n-alcohols is presented. Methyl ethers are used as homomorphs (model monomers). Values of four adjustable parameters, i.e. enthalpy and entropy of association and two structural parameters, obtained by a regression on experimental data are physically meaningful. The results are analysed and compared with some other thermodynamic and spectroscopic data. The presented model can be directly extended to mixtures with inert solvents.

Thermodynamics of associating component + saturated hydrocarbon mixtures at low pressures. II. Extension of the model to correlate isothermal vapour [sbnd]liquid equilibria and volumetric properties of n-alcohol + n-alkane mixtures

Abstract The model, recently used to describe saturated vapour pressures and liquid volumes of pure n-alcohols, is extended to mixtures of n-alcohols with inert solvents and used to correlate vapour liquid equilibria and excess volumes of n-alcohol + n-alkane mixtures. The model with two binary parameters evaluated by regression on experimental data provides good representation of vapour liquid equilibria and satisfactory description of excess volumes. Empirical generalization of binary parameters, obtained by regression on 40 vapour liquid equilibrium data sets, enables good estimation of vapour liquid equilibria of n-alcohol + n-alkane mixtures. Predictive ability of the model, i.e. when setting the binary parameters equal to zero, is also examined.

Simultaneous calculations of VLE and saturated liquid and vapor volumes by means of a 3P1T cubic EOS

The three-parameter cubic equation of state with one parameter temperature-dependent (3P1T), P = RT/(V − b) − a(T)/[V(V + c) + b(3V + c)], recently developed for asymmetric mixture density calculations for nonpolar substances (Yu and Lu, 1987), has been applied to VLE calculations. The binary interaction parameter k 12 obtained from the conventional random VDW mixing rule for the mixture parameter a has been used for the prediction of volumes of saturated liquid (V ℓ ) and saturated vapor (V ν ) at the conditions of the VLE data. The 3P1T equation is as capable for VLE calculations as the Soave-Redlich-Kwong, the Peng-Robinson, the Schmidt-Wenzel and the translated Peng-Robinson equations, but it yields lower V ℓ deviations than these equations. The improvement is more evident for highly asymmetric mixtures. The suitability of the form of the equation for representing V ℓ of nonpolar compounds over a wide range of molecular weight is further demonstrated.

Bubble pressures and saturated liquid molar volumes of difluoromonochloromethane—fluorochloroethane binary mixtures: experimental data and modelling

A previously described apparatus (variable volume cell method) was used to obtain bubble pressures and saturated liquid molar volumes at four temperatures for systems involving difluoromonochloromethane with tetrafluorodichloroethane, trifluorotrichloroethane and difluoromonochloroethane. The experimental bubble pressures are well represented by the Peng-Robinson equation of state with one adjusted interaction parameter. Adjusting a second interaction parameter does not significantly improve the representation. Soave and Mathias equations give a quite similar representation. Saturated liquid molar volumes calculated from the different equations of state, with binary interaction parameters adjusted on bubble pressure data, do not agree well with experimental results: the standard deviation between calculated and experimental densities is ≈ 8% with the Peng-Robinson equation of state and ≈ 18% with that of Soave and Mathias.

Vapour-liquid equilibrium study of methane and western shale oil

Abstract The bubble point pressures, saturated molar liquid volumes, and densities of a shale oil from the Green River formation in Utah, and a distillation fraction of the oil were experimentally determined as a function of temperature and methane mole fraction. These properties were measured in a static VLE apparatus capable of measuring pressures to 34,500 kPa and temperatures to 450 K. The phase change at the bubble point for the mixtures of oil and methane was determined using the statistical method of splines. The densities for the crude shale oil have been extrapolated to 288.7K (60 °F) using a standard API correlation.

Use of a Cubic Equation to Predict Surface Tension and Spinodal Limits

The very general Shamsundar–Murali cubic equation is used to interpolate p–v–T data into the metastable and unstable regions. This yields a spinodal line that closely matches the homogeneous nucleation limit predicted by an improved kinetic theory. Only the pressure, the saturated liquid and vapor volumes, and the liquid compressibility at saturation, as well as one compressed liquid data point, are needed to use the cubic equation for the interpolation process. The equation also yields an accurate prediction of the temperature dependence of surface tension when it is substituted in van der Waals’ surface tension formula. Thus, by capitalizing on the inherent relation among the p–v–T equation, the spinodal prediction, and the surface tension—all three—it is possible to obtain each with high accuracy and minimal experimental data.

Prediction of vapor pressures and saturated volumes with a simple cubic equation of state: Part I. A reliable data base

Abstract A reliable unbiased data base comprising (i) vapor pressures, P s , (ii) critical properties, T c , and P c , (iii) acentric factors, w, (iv) an improved correlation for critical compressibility, Z c , and (v) saturated liquid volume, V s , for the Cl to C16 n-alkanes is presented. For vapor pressures, the data base covers a wide range of pressures for each compound, from 0.001 kilopascal through the critical pressure for some of them, with an estimated accuracy of 2 percent from the critical pressure to 0.1 kilopascal, and about 5 percent accuracy below 0.1 kilopascal. Critical properties are screened by plotting T c and P c versus the number of carbon atoms. Acentric factors, w, are re-evaluated using the vapor pressure data base. Plotting many experimental Zc data versus w gives a correlation which better represents Zc at high w. A saturated liquid volume data base was generated from the correlation of Hankinson and Thomson (1979), after it was tested with experimental data. This data base of P s , T c , P c w, Z c , and V s can be used in the development of equations of state (EOS) and the establishment of their limits of applicability, which is demonstrated with the translated Van der Waals (VdW-711) EOS in Part II.

Prediction of vapor pressures and saturated molar volumes with a simple cubic equation of state: Part II: The Van der Waals - 711 EOS

Abstract A simple cubic equation of state (EOS), the VdW-711 translation of the Van der Waals EOS is presented. It is applicable to nonpolar and slightly polar compounds. It was developed by using the reliable data base of vapor pressure, critical property, acentric factor, and saturated liquid volume values of Part I. Excellent results for vapor pressures, from 0.1 kPa to the critical, and for saturated molar volumes are obtained with errors below 5% and typically about 2 to 3%. Below 0.1 kPa, it is demonstrated that all of the cubic EOS investigated are unreliable for vapor pressure predictions. The equation has been successfully applied to compounds with acentric factors of up to 0.907, including several fossil fuel model compounds. It is shown that in the case of uncertainies in the critical properties and acentric factor values of hydrocarbons, good vapor pressure predictions are obtained with the VdW-711 EOS using estimates of these properties from the Lin and Chao correlation.

A generalized technique to obtain pure component parameters for two-parameter equations of state

Abstract A generalized technique is presented for the calculation of the pure component parameters for use in a general two-parameter equation of state. The method requires as input data the vapor pressure and saturated liquid volume of a component at a given temperature, and is both accurate and simple to use. Correlations for the calculation of the parameters are presented for the van der Waals, Redlich—Kwong and Peng—Robinson forms of cubic equations of state. A comparison is made between the new method and the corresponding-states approach.

Effects of Pore Pressure and Mud Filtration on Drilling Rates in a Permeable Sandstone

Summary During laboratory drilling tests in a permeable sandstone, the effects of pore pressure and mud filtration on penetration rates were measured. Four water-based muds were penetration rates were measured. Four water-based muds were used to drill four saturated sandstone samples. The drilling tests were conducted at constant borehole pressure while different backpressures were maintained on the filtrate flowing from the bottom of the sandstone samples. Bit weight was varied also. Filtration rates were measured while circulating mud during drilling and with the bit off bottom. Penetration rates were found to be related qualitatively to the difference between the filtration rates measured while drilling and circulating. There was no observed correlation between standard API filtration measurements and penetration rate. Introduction A better understanding of the effects of pore pressure and mud filtration on penetration rates and how these effects relate to standard API filtration properties was sought during full-scale laboratory drilling tests in a permeable sandstone with four different laboratory-prepared muds. Measurements of penetration rate and filtration rate were made as mud type, bit weight, and backpressure on the filtrate produced from the sandstone samples were varied. Other parameters-such as rock type, bit type, rotary speed, flow rate, borehole pressure, confining pressure, overburden stress, mud temperature, and penetration interval were held constant. The filtrate volume vs. time or filtration rate measured while drilling is herein designated "drilling" filtration rate. "Circulating" filtration rate refers to filtration rate measured with the bit off bottom and with mud circulating in the borehole. From the measured filtration rates, pressure drops through the rock samples were calculated pressure drops through the rock samples were calculated using Darcy's law. After the pressure drops were subtracted from the measured total drop across the rock (borehole pressure minus backpressure), the pressure drops across the mud filter cake at the bit/rock interface were determined. The test results are presented in terms of these pressure drops. pressure drops. Changes in penetration rate with bit weight and pressure drop across the filter cake were examined. The relationship between penetration rate and filtration rate was determined. An attempt to correlate the drilling test results with standard API filtration properties was also made. Drill Bit, Rocks, and Muds A 77/8-in. [20.07cm] diameter Smith F-3 bit (IADC 5–3-6) with three 10/32-in. [0.84-cm] diameter nozzles was used for the drilling tests. The bit had a pressure drop across the nozzles of approximately 900 psi [6205.3 kPa] at 240 gal/min [15.14 dm3/s] for the 9.5-lbm/gal [1138.35-kg/m3] mud used during the tests. Four Berea sandstone samples (15.5-in. [39.37-cm] diameter by 36-in. [91.44-cm]) length were drilled. Before drilling, the Berea sandstone samples were evacuated for a minimum of 24 hours, saturated with tap water, weighed, and stored under water. From the saturated weight, bulk volume, porosity, and grain density, water saturation was then calculated. The samples were saturated between 95 and 100%. After the samples were jacketed between steel end caps, the top end cap was filled with water to maintain the saturation. The Berea sandstone samples had a grain density of 2.65 gm/cm3 [2650.0 kg/m3], a porosity of 20%, an unconfined strength of 9,000 psi [62 052.8 kPa], and a permeability of 0.2 darcies. The four water-based drilling muds tested included a low-solids, nondispersed mud (LSND); a low-solids, nondispersed mud with sodium polyacrylate filtration control additive (LSND-SPA); a dispersed (DISP) mud; and an oil emulsion (OIL EMUL) mud. Approximately 120 bbl [19.08 m3] of the LSND mud was prepared first. The LSND mud had a relatively high API filtration rate of 0.92 cu in./30 min [15 cm3/1800 s]. Various materials were added to portions of the LSND mud to obtain the LSND-SPA, DISP, and OIL EMUL muds, which had relatively low API filtration rates of 0.43 cu in./30 min [7 cm3/1800 s]. Composition of the muds is given in Table 1. The methods used to reduce the API filtration rate of the LSND mud reflect typical choices that are available when filtration reduction is necessary during drilling. Ferguson and Klotz performed filtration experiments while drilling with various mud types; Krueger later studied the effects of common filtration control additives on filtration while circulating. Many of these additives require significant amounts of shearing and circulating time to reach full effectiveness. In view of this, the performance of these additives in laboratory-prepared muds performance of these additives in laboratory-prepared muds may differ somewhat from the performance that would be observed in field-conditioned muds. Mud properties were measured before and after each drilling test (Table 2). JPT P. 1671

Irreversible and reversible annealing of paramagnetic oxygen vacancies (E′1 centers) in oxygen-implanted amorphous SiO2

The creation/annihilation dynamics of E1 defects induced in thermal SiO2 by implantation of N+ and O+ ions has been studied using electron paramagnetic resonance. A new effect of the irreversible self-annealing of E′1 defects has been observed for RT O+ implants. This effect correlates with the average concentration of implanted oxygen atoms within the saturated damage volume. Low-temperature (100<T<300 °C) E1 defect annealing behavior appears to correspond to reversible oxygen vacancy charge transformation E′1⇄B2 via a hole release/trapping process. Irreversible thermal annealing of E1 centers is observed at temperatures T>500 °C. However, the isochronal annealing behavior does not correspond to Waite’s model based on the molecular oxygen diffusion mechanism.

The vapour pressures and saturated vapour volumes of O-fluorotoluene in the temperature range 450–530 K

Abstract The vapour pressure of a degassed sample of O-fluorotoluene was measured in the temperature range 452.9K to 530.4K. Also the saturated vapour volume was measured in the same temperature range. The measured vapour pressures were fitted to two alternative vapour pressure equations by least squares procedures.

Thermodynamic characterization of vaporization of the fourth group elements

Thermodynamic characterization of silicon, germanium, tin, and lead vaporization is performed by the method applied earlier to alkali metals and carbon, i.e., by evaluation of analytical expressions representing dependence of the second virial coefficient and vapor pressure on temperature. Starting from saturation pressure values given as a sum of partial pressure of present species, through a modified procedure applied before to carbon, the parameters of anticipated forms ofB=f(T) andP=f(T) are optimized with very high degree of correlation. A new, simple, and efficient procedure for optimization ofP=f(T) parameters from particularP data is derived. The values of\(\Delta _\upsilon H_0^0 \left( {III} \right)\) and\(\Delta _\upsilon H_0^0 \left( {II} \right)\), calculated for all the elements from the evaluated relationsB=f(T) andP=f(T), agree mutually as well as with thecodata recommended values. Applicability and efficiency of this method when applied to thermodynamic characterization of vaporization of the fourth group elements is justified through comparison of the obtained vapor pressure and saturated vapor molar volume values with the corresponding values deduced from the published data.