Showing papers on "Binary system published in 1983"

Calculation of the thermodynamic and geochemical consequences of nonideal mixing in the system H 2 O-CO 2 -NaCl on phase relations in geologic systems; metamorphic equilibria at high pressures and temperatures

Abstract: Fluid inclusion analyses reported in the literature, together with experimental data and thermodynamic calculations indicate that nonideality in the system H 2 O-CO 2 -NaCl may have a profound effect on phase relations in metamorphic processes. High concentrations of NaCl in the system H 2 O-CO 2 -NaCl increase substantially the size of the two-phase (liquid + vapor) region by raising the consolute temperature for a given pressure and ratio of the mole fractions of H 2 O and NaCl to more than double that in the binary system H 2 O-CO 2 . As a consequence, fluid immiscibility may occur at considerable depth during progressive metamorphism of siliceous carbonates. The effect of nonideal mixing of H 2 O, CO 2 and NaCl on equilibrium constraints in metamorphic systems can be assessed quantitatively on phase diagrams generated with the aid of a modified Redlich-Kwong equation of state (Bowers and Helgeson, 1983). Diagrams of this kind indicate that increasing NaCl concentration results in higher temperatures and/or lower predicted values of X co2 for equilibrium mineral assemblages than would be true for the binary system H 2 O-CO 2 . Transection of various mineral stability fields by saturation lines representing equilibrium between the aqueous phase and calcite, dolomite, or magnesite on logarithmic activity diagrams is also highly sensitive to the NaCl concentration in the aqueous phase.--Modified journal abstract.

The effect of low-velocity, low-mass intruders (collisionless gas) on the dynamical evolution of a binary system

Abstract: More than 20,000 computer-simulated encounters between low-mass (compared to the binary components) intruders and binary systems have been made. These calculations were made in the important (and difficult) limit where the intruder velocity is small compared to the orbital velocity of the binary. The dependence of the encounters on orbital eccentricity, on the mass ratios of the binary components, and on the impact parameter was found. These encounters increase the binding energy of the binary. At zero impact parameter, the average increase in the binding energy is proportional to the square of the binary orbital eccentricity. However, the increase in the binding energy decreases much faster with increasing impact parameter as the eccentricity increases. The net result is that the total cross section for increasing the binding energy of a binary through encounters with low-mass intruders is independent of the orbital eccentricity of the binary. The average increase in the binding energy per encounter is directly proportional to the mass of the intruder (in the limit where its mass is small compared to the binary mass). If the binary components are equally massive, the probability that the intruder is captured into a long-lived orbit which persists for at least 1.5more » x 10/sup 5/ integration steps or about 700 revolutions of the original binary is only about 1% at zero impact parameter. However, the probability of long-term capture climbs rapidly for encounters in which the closest approach, R/sub min/, of the intruder to the binary is greater than 0.5 of the semimajor axis a/sub 0/ of the orbit. It climbs to about 20% at R/sub min//a/sub 0/ = 1.9 and then falls off rapidly at larger R/sub min/. Here the capture is due to the tidal field of the binary. The probability of long-term capture increases as the orbital eccentricity increases. 14 references, 9 figures, 4 tables.« less

Dissolution enthalpies of NaI in binary mixtures of water with aliphatic alcohols and methylcellosolve at 298.15 K. Enthalpic pair interaction coefficients of NaI-nonelectrolyte in water solution

Abstract: The enthalpy of solution, ΔHsol, of NaI in methanol + water, ethanol + water, n-propanol + water, isopropanol + water, and methoxyethanol + water at all compositions and ΔHsol of NaI in s-butanol +...

Thermodynamic properties of binary alloys of platinum metals II: Ir-Pt system

Abstract: The iridium activity aIr for Ir-Pt alloys at 1383, 1468 and 1573 K was determined by means of a reactive carrier gas method in which dry oxygen was used as the carrier gas. The corresponding platinum activity aPt, was calculated from the Gibbs-Duhem relations. Both activities and the relative partial molar quantities derived from them exhibit a composition-independent region (0.50 < NIr < 0.90) in the temperature range investigated. There should be shortrange ordering in these alloy phases. On the basis of the present investigation, it is predicted that a miscibility gap exists in the solid solution phase at temperatures up to 1573 K in the Pt-Ir binary system.

Physical Properties and Structure of Binary Ferrite Melts

Abstract: Densite, conductivite, viscosite, tension superficielle de Na 2 O−Fe 2 O 3 , RO-Fe 2 O 3 R=Ca, Sr, Ba

Thermodynamics of binary mixtures: Volumes, heat capacities, and dilution enthalpies for then-pentanol+2-methyl-2-butanol system

Abstract: The densities, heat capacities, and dilution enthalpies ofn-pentanol+2-methyl-2-butanol mixtures have been measured, in many cases as a function of temperature, over the complete mole fraction range. Excesses thermodynamic properties, apparent and partial molar heat capacities, volumes and expansibilities were derived. The concentration and temperature dependences of these functions are discussed in terms of the variations of the structure of the system caused by the participation of the two alcohol molecules (with quite different steric hindrance of the alkyl chain around the-OH group) in the dynamic intermolecular association process through hydrogen bonding.

Densities and viscosities of binary solvent mixtures of N-methylacetamide with aliphatic alcohols

Abstract: Etude avec les methanol, ethanol, propanols, butanol-1, methyl-2 propanol-2. Calcul des grandeurs d'exces

Optimization of binary thermodynamic and phase diagram data

Abstract: An optimization technique based upon least squares regression is presented to permit the simultaneous analysis of diverse experimental binary thermodynamic and phase diagram data. Coefficients of polynomial expansions for the enthalpy and excess entropy of binary solutions are obtained which can subsequently be used to calculate the thermodynamic properties or the phase diagram. In an interactive computer-assisted analysis employing this technique, one can critically analyze a large number of diverse data in a binary system rapidly, in a manner which is fully self-consistent thermodynamically. Examples of applications to the Bi-Zn, Cd-Pb, PbCl2-KCl, LiCl-FeCl2, and Au-Ni binary systems are given.

Viscosity, refractive index, and surface tension of multicomponent systems: Mathematical representation and estimation from data for binary systems

Abstract: An equation previously developed for estimation of the excess thermodynamic properties of multicomponent systems from binary mixing data has been applied to other physical properties through extrathermodynamic properties such as the excess Gibbs free energy of activation for viscous flow, molar refractivity, and exess surface free energy. This equation provides reasonably accurate predictions for viscosity, refractive index and surface tension of ternary and quaternary systems, given the properties of the various binary combinations of the components. The equation also serves quite well as a point-of-departure for mathematical representation of experimental data, in that all of the data considered could be represented within experimental uncertainty with the aid of no more than one adjustable parameter for each multicomponent system.

Emergence of Smectic Mesophase in Binary Mixtures of Pure Nematogens

Abstract: Binary mixtures both components of which are liquid crystals are known to form continuous mixed liquid crystals.1 Most of them do not undergo any change in their mesomorphic textures, though a few have been found to give rise to different textures.2 We report here a binary system consisting of (A) p-nitrophenyl-p'-n-amyloxycinnamate (90.5–120.5°) and (B) p-methoxyphenyl-p'-n-heptyloxycinnamate (91.0–120.5°) which transforms the original nematic texture into a mixed smectic A texture over a range of temperature and concentration. Both components individually are nematic liquid crystals. In their binary mixtures, a two dimensional more ordered mixed Smectic A mesophase emerges between 5.0–92.5 mol% of p-methoxyphenyl-p'-n-heptyloxycinnamate over a temperature range of about 50–105° at its maximum. The mixed smectic-nematic transition curve shows a marked rounded concavity, extrapolation of which on either side yields values of latent transition temperatures 77.0° and 66.5° for the components A and ...

Photocatalytic oxidation of liquid alcohols and binary alcohol mixtures by rutile

Abstract: The photocatalytic oxidation of liquid ethanol, propan-1-ol, propan-2-ol and butan-2-ol, together with the binary mixtures ethanol + propan-2-ol and propan-1-ol + propan-2-ol, has been investigated using rutile suspensions irradiated with 366 nm u.v. light at temperatures in the range 275–313 K. Activities and activation energies for product formation from the individual alcohols were effectively identical. The single activation energy is considered to be the energy required to promote photoelectrons from traps into the rutile conduction band. With the binary mixtures both the activity and activation energy for total carbonyl compound formation were composition independent and approached those of the individual alcohols. Selectivities for specific products were a function of both composition and temperature, and are considered to reflect the availability of the parent alcohols within a saturated physisorbed layer on the rutile surface. The results are discussed in terms of an established radical mechanism.

Orbital motion and mass flow in the interacting binary Be star HR 2142

Abstract: The discovery of an unusual, periodic, two-component shell phase of short duration in the 'classical' Be star HR2142 (HD41335, MWC133) offered convincing evidence that this object is a mass-transfer binary system. A model based solely on the phase-dependent behavior of the hydrogen shell lines in this 80(d).860 binary was developed by Peters and Polidan (1973) and by Peters (1976). The present investigation is concerned with a refinement to the earlier model, taking into account the utilization of an orbital solution obtained from measurements of the wings of the broad photospheric features observed in the rapidly rotating primary. Velocities and equivalent widths from the sharp 'shell' lines, presumably formed in or near the gas stream, provide additional information on the mass flow in the Balmer-line-formation region.

Studies on Salt Hydrates for Latent Heat Storage. IV. Crystallization in the Binary System CH3CO2Na–H2O

Abstract: In the binary system CH3CO2Na–H2O, crystallization temperature on slow cooling from a melt, glass transition temperature and crystallization temperature on slow heating from a quenched vitrified solid were measured by varying the CH3CO2Na concentration. The crystallization behaviour in the binary system CH3CO2Na–H2O is characterized as follows; (1) crystallization region of ice extends into the CH3CO2Na-rich side from the eutectic composition, (2) a hard crystallization region exists in the composition between CH3CO2Na 35wt% and 40wt%, (3) the crystallization temperature range of CH3CO2Na·3H2O is from −50 °C to −30 °C and very narrow.

Studies on Salt Hydrate for Latent Heat Storage, II. Eutectic Mixture of Pseudo-binary System CH3CO2Na·3H2O–CO(NH2)2

Abstract: With a view of developing latent heat storage materials, mixtures of pseudo-binary system, CH3CO2Na·3H2O–CO(NH2)2 (sodium acetate trihydrate–urea) were subjected to differentital scanning calorimetry, and the partial phase diagram for ternary system CH3CO2Na–CO(NH2)2–H2O at ambient pressure was constructed. The eutectic mixture, containing 0.6 mass fraction of CH3CO2Na·3H2O and 0.4 mass fraction of CO(NH2)2, melts congruently at 31.5 °C with a heat of fusion of 226 J/g, which is larger than the heat of fusion of CaCl2·6H2O, 180 J⁄g. Thus, mixtures of system CH3CO2Na·3H2O–CO(NH2)2 are promising for solar energy storage.

On the stability of close binaries in hierarchical three-body systems

Abstract: The Hill-type stability (cf. closure of the zero-velocity curves in the circular restricted three-body problem) of general hierarchical three-body systems is examined analytically in the case where the total mass of the binary is small in comparison to the mass of the external body (e.g. systems of the type Planet-Satellite-Sun, Planet-Planet-Star, etc.). This is compared with results derived by Szebehely, Markellos and Roy in the Planet-Satellite-Sun case of the circular restricted three-body problem. It is demonstrated how the Hill-type stability is affected by the sense of revolution of the binary, i.e. corotational or contrarotational, and the mass ratio within the binary. The effect of the difference in longitudes of the bodies in their orbits is also examined.

A thermodynamic assessment of the aluminum-titanium system

Abstract: The thermochemical properties and phase relationship of the aluminum-titanium system were evaluated. The selected values on the thermodynamic properties of various phases are tabulated.

Thermal analysis of binary systems of the pharmaceuticals trimethoprim and benzoic acid

Abstract: Thermal analysis of the binary system benzoic acid (BA) and trimethoprim (TMP) provided evidence of the formation of two molecular compounds. BA-TMP and two crystalline forms of (BA)2-TMP were characterized on the basis of their thermodynamic parameters as well as of crystallographic and spectroscopic properties. The availability of these compounds (by recrystallization) allowed interpretation of thermal effects in the DSC curves of the mixtures and the theoretical phase diagrams could be drawn. The results are consistent with the model of a very slight dissociation of the molecular compounds in the melt.