Log in

Relevant bibliographies by topics / Fugacity coefficient / Journal articles

To see the other types of publications on this topic, follow the link: Fugacity coefficient.

Journal articles on the topic 'Fugacity coefficient'

Author: Grafiati

Published: 4 June 2021

Last updated: 15 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Fugacity coefficient.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Hu, Jiawen, Rong Wang, and Shide Mao. "Some useful expressions for deriving component fugacity coefficients from mixture fugacity coefficient." Fluid Phase Equilibria 268, no. 1-2 (2008): 7–13. http://dx.doi.org/10.1016/j.fluid.2008.03.007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

CHEN, Fei-Wu, Cong Qian Gu, Wei-Lan Qian, and Xu-Qin Li. "The Fugacity Coefficient of Non-Ideal Gas and Activity Coefficient of Non-Ideal Solution." University Chemistry 32, no. 8 (2017): 66–70. http://dx.doi.org/10.3866/pku.dxhx201701025.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Callegaro, Sara, Kalotina Geraki, Andrea Marzoli, Angelo De Min, Victoria Maneta, and Don R. Baker. "The quintet completed: The partitioning of sulfur between nominally volatile-free minerals and silicate melts." American Mineralogist 105, no. 5 (2020): 697–707. http://dx.doi.org/10.2138/am-2020-7188.

Full text

Abstract:

Abstract Magmatic systems are dominated by five volatiles, namely H2O, CO2, F, Cl, and S (the igneous quintet). Multiple studies have measured partitioning of four out of these five volatiles (H2O, CO2, F, and Cl) between nominally volatile-free minerals and melts, whereas the partitioning of sulfur is poorly known. To better constrain the behavior of sulfur in igneous systems we measured the partitioning of sulfur between clinopyroxene and silicate melts over a range of pressure, temperature, and melt composition from 0.8 to 1.2 GPa, 1000 to 1240 °C, and 49 to 66 wt% SiO2 (13 measurements). Additionally, we determined the crystal-melt partitioning of sulfur for plagioclase (6 measurements), orthopyroxene (2 measurements), amphibole (2 measurements), and olivine (1 measurement) in some of these same run products. Experiments were performed at high and low oxygen fugacities, where sulfur in the melt is expected to be dominantly present as an S6+ or an S2– species, respectively. When the partition coefficient is calculated as the total sulfur in the crystal divided by the total sulfur in the melt, the partition coefficient varies from 0.017 to 0.075 for clinopyroxene, from 0.036 to 0.229 for plagioclase, and is a maximum of 0.001 for olivine and of 0.003 for orthopyroxene. The variation in the total sulfur partition coefficient positively correlates with cation-oxygen bond lengths in the crystals; the measured partition coefficients increase in the order: olivine &lt; orthopyroxene &lt; clinopyroxene ≤ amphibole and plagioclase. At high oxygen fugacities in hydrous experiments, the clinopyroxene/melt partition coefficients for total sulfur are only approximately one-third of those measured in low oxygen fugacity, anhydrous experiments. However when the partition coefficient is calculated as total sulfur in the crystal divided by S2– in the melt, the clinopyroxene/melt partition coefficients for experiments with melts between ~51 and 66 wt% SiO2 can be described by a single mean value of 0.063 ± 0.010 (1σ standard deviation about the mean). These two observations support the hypothesis that sulfur, as S2–, replaces oxygen in the crystal structure. The results of hydrous experiments at low oxygen fugacity and anhydrous experiments at high oxygen fugacity suggest that oxygen fugacity has a greater effect on sulfur partitioning than water. Although the total sulfur clinopyroxene-melt partition coefficients are affected by the Mg/(Mg+Fe) ratio of the crystal, partition coefficients calculated using S2– in the melt display no clear dependence upon the Mg# of the clinopyroxene. Both the bulk and the S 2– partition coefficients appear unaffected by IVAl in the clinopyroxene structure. No effect of anorthite content nor of iron concentration in the crystal was seen in the data for plagioclase-melt partitioning. The data obtained for orthopyroxene and olivine were too few to establish any trends. The partition coefficients of total sulfur and S 2– between the crystals studied and silicate melts are typically lower than those of fluorine, higher than those of carbon, and similar to those of chlorine and hydrogen. These sulfur partition coefficients can be combined with analyses of volatiles in nominally volatile-free minerals and previously published partition coefficients of H2O, C, F, and Cl to constrain the concentration of the igneous quintet, the five major volatiles in magmatic systems.

APA, Harvard, Vancouver, ISO, and other styles

4

Parsafar, Gholamabbas, and F. Madani. "An analytical expression for the fugacity coefficient of the supercritical fluids." High Temperatures-High Pressures 35/36, no. 5 (2003): 529–39. http://dx.doi.org/10.1068/htjr122.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Szarawara, Jósef, and Andrzej Gawdzik. "Method of calculation of fugacity coefficient from cubic equations of state." Chemical Engineering Science 44, no. 7 (1989): 1489–94. http://dx.doi.org/10.1016/0009-2509(89)80025-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Míka, Vladimír. "A generalized treatment of cubic equations of state." Collection of Czechoslovak Chemical Communications 54, no. 11 (1989): 2879–95. http://dx.doi.org/10.1135/cccc19892879.

Full text

Abstract:

From the formula proposed for the van Waals type equations of state, general expressions for the compressibility factor, the departure functions and the fugacity coefficient are derived. Easy construction of the formula needed is possible for any of the equations listed in the paper. The method is applicable to other equations of this type.

APA, Harvard, Vancouver, ISO, and other styles

7

Amaya-Tapia, A., S. Y. Larsen, and M. Lassaut. "Third Bose fugacity coefficient in one dimension, as a function of asymptotic quantities." Annals of Physics 326, no. 2 (2011): 406–25. http://dx.doi.org/10.1016/j.aop.2010.10.004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Zhao, Weilong, Hao Wu, Jing Wen, Xin Guo, Yongsheng Zhang, and Ruirui Wang. "Simulation Study on the Influence of Gas Mole Fraction and Aqueous Activity under Phase Equilibrium." Processes 7, no. 2 (2019): 58. http://dx.doi.org/10.3390/pr7020058.

Full text

Abstract:

This work explored the influence of gas mole fraction and activity in aqueous phase while predicting phase equilibrium conditions. In pure gas systems, such as CH4, CO2, N2 and O2, the gas mole fraction in aqueous phase as one of phase equilibrium conditions was proposed, and a simplified correlation of the gas mole fraction was established. The gas mole fraction threshold maintaining three-phase equilibrium was obtained by phase equilibrium data regression. The UNIFAC model, the predictive Soave-Redlich-Kwong equation and the Chen-Guo model were used to calculate aqueous phase activity, the fugacity of gas and hydrate phase, respectively. It showed that the predicted phase equilibrium pressures are in good agreement with published phase equilibrium experiment data, and the percentage of Absolute Average Deviation Pressures are given. The water activity, gas mole fraction in aqueous phase and the fugacity coefficient in vapor phase are discussed.

APA, Harvard, Vancouver, ISO, and other styles

9

Zhou, Li, and Yaping Zhou. "Determination of compressibility factor and fugacity coefficient of hydrogen in studies of adsorptive storage." International Journal of Hydrogen Energy 26, no. 6 (2001): 597–601. http://dx.doi.org/10.1016/s0360-3199(00)00123-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Palencia Muñoz, Miguel Fernando, Natalia Prieto-Jiménez, and Germán González Silva. "Liquid balance - steam for methanol mixing - Benzen using the Peng Robinson and Van-Laar models." Respuestas 24, no. 1 (2019): 34–41. http://dx.doi.org/10.22463/0122820x.1807.

Full text

Abstract:

This paper is related to the procedure for calculating curves dew point and bubble point of a binary system, consisting of the methanol and benzene mixture to 45°C, using the Peng-Robinson cubic equation to calculate the fugacity coefficient of gas i in the mixture, and Van Laar model to calculate the activity coefficient of component i in the liquid mixture. Then a comparison between the theoretical data with the experimental data and later with the commercial simulator Hysys-Aspen, which applies the model of Wilson. The simulation was validated with experimental data,in addition to comparing the results with a commercial simulator.

APA, Harvard, Vancouver, ISO, and other styles

11

Lawal, Akanni S., and Ernst T. van der Laan. "A partial molar fugacity coefficient useful for changing mixing rules of cubic equations of state." Fluid Phase Equilibria 95 (April 1994): 109–21. http://dx.doi.org/10.1016/0378-3812(94)80064-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Mohammadi, Amir H., and Dominique Richon. "Development of Predictive Techniques for Estimating Liquid Water-Hydrate Equilibrium of Water-Hydrocarbon System." Journal of Thermodynamics 2009 (February 25, 2009): 1–12. http://dx.doi.org/10.1155/2009/120481.

Full text

Abstract:

In this communication, we review recent studies by these authors for modeling the -H equilibrium. With the aim of estimating the solubility of pure hydrocarbon hydrate former in pure water in equilibrium with gas hydrates, a thermodynamic model is introduced based on equality of water fugacity in the liquid water and hydrate phases. The solid solution theory of Van der Waals-Platteeuw is employed for calculating the fugacity of water in the hydrate phase. The Henry's law approach and the activity coefficient method are used to calculate the fugacities of the hydrocarbon hydrate former and water in the liquid water phase, respectively. The results of this model are successfully compared with some selected experimental data from the literature. A mathematical model based on feed-forward artificial neural network algorithm is then introduced to estimate the solubility of pure hydrocarbon hydrate former in pure water being in equilibrium with gas hydrates. Independent experimental data (not employed in training and testing steps) are used to examine the reliability of this algorithm successfully.

APA, Harvard, Vancouver, ISO, and other styles

13

Kumari, Anupama, Shadman Hasan Khan, A. K. Misra, C. B. Majumder, and Amit Arora. "Hydrates of Binary Guest Mixtures: Fugacity Model Development and Experimental Validation." Journal of Non-Equilibrium Thermodynamics 45, no. 1 (2020): 39–58. http://dx.doi.org/10.1515/jnet-2019-0062.

Full text

Abstract:

AbstractA fugacity-based thermodynamic model for hydrate has been used to determine the equilibrium pressures of hydrate formation. This fugacity-based model uses the PRSV equation of state, which is used to represent the gas phases in the hydrate. The parameters of the model are fitted to the experimental data of binary guest hydrates. The present study is aimed at investigating binary mixtures of {\text{CH}_{4}}–{\text{H}_{2}}S, {\text{C}_{3}}{\text{H}_{8}}–{\text{N}_{2}}, {\text{N}_{2}}–{\text{CO}_{2}}, {\text{CH}_{4}}–i-butane, {\text{C}_{3}}{\text{H}_{8}}–i-butane, {\text{CH}_{4}}–n-butane, {\text{C}_{3}}{\text{H}_{8}}–n-butane, i-butane–{\text{CO}_{2}}, and n-butane–{\text{CO}_{2}} hydrates, which have not been modeled before. Unlike previous studies, the Kihara potential parameters were obtained using the second virial coefficient correlation and the data of viscosity for gases. The fugacity-based model provides reasonably good predictions for most of the binary guest hydrates ({\text{CH}_{4}}–{\text{C}_{3}}{\text{H}_{8}}). However it does not yield good prediction for hydrates of ({\text{CO}_{2}}–{\text{C}_{3}}{\text{H}_{8}}). The transitions of hydrate structure from sI to sII and from sII to sI have been also predicted by this model for binary guest hydrates. The AAD % calculated using the experimental data of natural gas hydrates is only 10 %, which is much lower than the AAD % calculated for the equilibrium data predicted by the VdP-w model.

APA, Harvard, Vancouver, ISO, and other styles

14

Fei, Hongzhan, Sanae Koizumi, Naoya Sakamoto, et al. "Pressure, temperature, water content, and oxygen fugacity dependence of the Mg grain-boundary diffusion coefficient in forsterite." American Mineralogist 103, no. 9 (2018): 1354–61. http://dx.doi.org/10.2138/am-2018-6480.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Gupta, A. Das, A. Dey, C. T. Moynihan, and M. Tomozawa. "Water Diffusion in Glasses: Influence of Pressure and Fugacity on Diffusion Coefficient of Hydroxyl and Molecular Groups." Transactions of the Indian Ceramic Society 53, no. 1 (1994): 8–20. http://dx.doi.org/10.1080/0371750x.1994.10804621.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Bornyakov, V. G., D. Boyda, V. Goy, et al. "Restoring canonical partition functions from imaginary chemical potential." EPJ Web of Conferences 175 (2018): 07027. http://dx.doi.org/10.1051/epjconf/201817507027.

Full text

Abstract:

Using GPGPU techniques and multi-precision calculation we developed the code to study QCD phase transition line in the canonical approach. The canonical approach is a powerful tool to investigate sign problem in Lattice QCD. The central part of the canonical approach is the fugacity expansion of the grand canonical partition functions. Canonical partition functions Zn(T) are coefficients of this expansion. Using various methods we study properties of Zn(T). At the last step we perform cubic spline for temperature dependence of Zn(T) at fixed n and compute baryon number susceptibility χB/T2 as function of temperature. After that we compute numerically ∂χ/∂T and restore crossover line in QCD phase diagram. We use improved Wilson fermions and Iwasaki gauge action on the 163 × 4 lattice with mπ/mρ = 0.8 as a sandbox to check the canonical approach. In this framework we obtain coefficient in parametrization of crossover line Tc(µ2B) = Tc(C−ĸµ2B/T2c) with ĸ = −0.0453 ± 0.0099.

APA, Harvard, Vancouver, ISO, and other styles

17

Lazzús, Juan A. "Hybrid Particle Swarm-Ant Colony Algorithm to Describe the Phase Equilibrium of Systems Containing Supercritical Fluids with Ionic Liquids." Communications in Computational Physics 14, no. 1 (2013): 107–25. http://dx.doi.org/10.4208/cicp.241011.150612a.

Full text

Abstract:

AbstractBased on biologically inspired algorithms, a thermodynamic model to describe the vapor-liquid equilibrium of binary complex mixtures containing supercritical fluids and ionic liquids, is presented. The Peng-Robinson equation of state with the Wong-Sandler mixing rules are used to evaluate the fugacity coefficient on the systems. Then, a hybrid particle swarm-ant colony optimization was used to minimize the difference between calculated and experimental bubble pressure, and calculate the binary interaction parameters for the excess Gibbs free energy of all systems used. Simulations are carried out in nine systems with imidazolium-based ionic liquids. The results show that the bubble pressures were correlated with low deviations between experimental and calculated values. These deviations show that the proposed hybrid algorithm is the preferable method to describe the phase equilibrium of these complex mixtures, and can be used for other similar systems.

APA, Harvard, Vancouver, ISO, and other styles

18

Huang, Xiao-Wen, Anne-Aurélie Sappin, Émilie Boutroy, Georges Beaudoin, and Sheida Makvandi. "Trace Element Composition of Igneous and Hydrothermal Magnetite from Porphyry Deposits: Relationship to Deposit Subtypes and Magmatic Affinity." Economic Geology 114, no. 5 (2019): 917–52. http://dx.doi.org/10.5382/econgeo.4648.

Full text

Abstract:

Abstract The trace element composition of igneous and hydrothermal magnetite from 19 well-studied porphyry Cu ± Au ± Mo, Mo, and W-Mo deposits was measured by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and then classified by partial least squares-discriminant analysis (PLS-DA) to constrain the factors explaining the relationships between the chemical composition of magnetite and the magmatic affinity and porphyry deposit subtypes. Igneous magnetite can be discriminated by relatively high P, Ti, V, Mn, Zr, Nb, Hf, and Ta contents but low Mg, Si, Co, Ni, Ge, Sb, W, and Pb contents, in contrast to hydrothermal magnetite. Compositional differences between igneous and hydrothermal magnetite are mainly controlled by the temperature, oxygen fugacity, cocrystallized sulfides, and element solubility/mobility that significantly affect the partition coefficients between magnetite and melt/fluids. Binary diagrams based on Ti, V, and Cr contents are not enough to discriminate igneous and hydrothermal magnetite in porphyry deposits. Relatively high Si and Al contents discriminate porphyry W-Mo hydrothermal magnetite, probably reflecting the control by high-Si, highly differentiated, granitic intrusions for this deposit type. Relatively high Mg, Mn, Zr, Nb, Sn, and Hf but low Ti and V contents discriminate porphyry Au-Cu hydrothermal magnetite, most likely resulting from a combination of mafic to intermediate intrusion composition, high chlorine in fluids, relatively high oxygen fugacity, and low-temperature conditions. Igneous or hydrothermal magnetite from Cu-Mo, Cu-Au, and Cu-Mo-Au deposits cannot be discriminated from each other, probably due to similar intermediate to felsic intrusion composition, melt/fluid composition, and conditions such as temperature and oxygen fugacity for the formation of these deposits. The magmatic affinity of porphyritic intrusions exerts some control on the chemical composition of igneous and hydrothermal magnetite in porphyry systems. Igneous and hydrothermal magnetite related to alkaline magma is relatively rich in Mg, Mn, Co, Mo, Sn, and high field strength elements (HFSEs), perhaps due to high concentrations of chlorine and fluorine in magma and exsolved fluids, whereas those related to calc-alkaline magma are relatively rich in Ca but depleted in HFSEs, consistent with the high Ca but low HFSE magma composition. Igneous and hydrothermal magnetite related to high-K calc-alkaline magma is relatively rich in Al, Ti, Sc, and Ta, due to a higher temperature of formation or enrichment of these elements in melt/fluids. Partial least squares-discriminant analysis on hydrothermal magnetite compositions from porphyry Cu, iron oxide copper-gold (IOCG), Kiruna-type iron oxide-apatite (IOA), and skarn deposits around the world identify important discriminant elements for these deposit types. Magnetite from porphyry Cu deposits is characterized by relatively high Ti, V, Zn, and Al contents, whereas that from IOCG deposits can be discriminated from other types of magnetite by its relatively high V, Ni, Ti, and Al contents. IOA magnetite is discriminated by higher V, Ti, and Mg but lower Al contents, whereas skarn magnetite can be separated from magnetite from other deposit types by higher Mn, Mg, Ca, and Zn contents. Decreased Ti and V contents in hydrothermal magnetite from porphyry Cu and IOA, to IOCG, and to skarn deposits may be related to decreasing temperature and increasing oxygen fugacity. The relative depletion of Al in IOA magnetite is due to its low magnetite-silicate melt partition coefficient, immobility of Al in fluids, and earlier, higher-temperature magmatic or magmatic-hydrothermal formation of IOA deposits. The relative enrichment of Ni in IOCG magnetite reflects more mafic magmatic composition and less competition with sulfide, whereas elevated Mn, Mg, Ca, and Zn in skarn magnetite results from enrichment of these elements in fluids via more intensive fluid-carbonate rock interaction.

APA, Harvard, Vancouver, ISO, and other styles

19

Chang, Yih-Bor, Brian K. Coats, and James S. Nolen. "A Compositional Model for CO2 Floods Including CO2 Solubility in Water." SPE Reservoir Evaluation & Engineering 1, no. 02 (1998): 155–60. http://dx.doi.org/10.2118/35164-pa.

Full text

Abstract:

Abstract This paper presents a three-dimensional, three-phase compositional model for simulating CO2 flooding including CO2 solubility in water. Both fully implicit and IMPES formulations are included. In this model, CO2 is allowed to dissolve in the aqueous phase while all other components except water exist in the oil and gas phases. Oil- and gas-phase densities and fugacities are modeled by a cubic equation of state. The aqueous phase properties are functions of the amount of dissolved CO2. CO2 solubility is computed using a CO2 fugacity coefficient table that is converted internally from input CO2 solubility data as a function of pressure at reservoir temperature. Correlations for computing the solubility of CO2 in water and other properties of CO2 saturated water are presented. Results for simulation runs with and without CO2 solubility in water are shown for comparison. IntroductIon Compositional models using a cubic equation of state are usually used to simulate the enhanced recovery process of gas injection. In most of the published models, for example Coats and Young and Stephenson, all hydrocarbon components exist in the oil and gas phases but are not allowed to dissolve in the aqueous phase. Usually, this assumption is adequate since the hydrocarbon solubility in water is low over the range of temperature and pressure for gas injection. Carbon dioxide, however, is an exception to this assumption. The solubility of CO2 in water is much higher than that of hydrocarbon components and is a factor that can not be neglected in the simulation process. This is especially true when CO2 is injected into a previously waterflooded reservoir or when CO2 is injected with water for mobility control. Tile objective of this paper is to model oil recovery processes involving CO2 injection while taking into account the effects of CO2 solubility in water. The effects of the presence of an aqueous phase on the phase behavior of CO2/hydrocarbon systems have been experimentally studied by Pollack et al. It was found that the presence of water reduces the amount of CO2 available for mixing with the hydrocarbons, and shifts the pressure-composition diagram of CO2/crude oil system. The solubility of CO2 in water is a function of temperature, pressure and water salinity. A thorough study of CO2 solubility data in distilled water was presented by Dodds et al. In general, CO2 solubility increases with pressure and decreases with temperature. An increase in salinity of the reservoir water decreases CO2 solubility significantly. Li and Nghiem used Henry's Law to estimate CO2 solubility in distilled water and used the scaled-particle theory to take into account the presence of salt in the aqueous phase. Enick and Klara also used Henry's Law to predict CO2 solubility in distilled water. Tile decreased solubility of CO2 in brine was accounted for empirically by a single factor correlated to the weight percent of dissolved solid. However, a wide scatter of data characterizes their correlation. A compositional model for simulating CO2 floods including CO2 solubility in water is presented. In this model, hydrocarbons and CO2 are allowed to exist in the oil and gas phases while only CO2 and water exist in the aqueous phase. A cubic equation of state is used to model oil- and gas-phase densities and fugacities. An input table of CO2 solubility in water, water formation volume factor, water compressibility and water viscosity is required for this model. These data, which are obtained either experimentally or generated from correlations, are entered as a function of pressure at reservoir temperature. The CO2 solubility in water is internally converted into a fugacity coefficient table as a function of pressure. The fugacity coefficients are then used to compute the amount of CO2 in water during simulation using the equality of component chemical potential constraint. The water formation volume factor, compressibility and viscosity are then computed as a function of the amount of CO2 dissolved in the water.

APA, Harvard, Vancouver, ISO, and other styles

20

Gao, Yu Ming, Ji Lin Cao, Panpan Chen, Hong Fei Guo, and Zhao Yang Tan. "Equilibrium Studies on the System H₂O-H₂O₂-CO(NH₂)₂-C₃H₈." Advanced Materials Research 233-235 (May 2011): 1690–93. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.1690.

Full text

Abstract:

The phase equilibrium of the quaternary system H2O-H2O2-CO(NH2)2-C3H8 with gas hydrate formation had been studied at high pressure and low temperature. The temperature and pressure of gas hydrate formed from different hydrogen peroxide concentration aqueous were determined at adding surfactants and no surfactants separately. It was concluded that the equilibrium pressure of gas hydrate formation was increasing with the increase of the hydrogen peroxide concentration, the urea concentration and the temperature, the mother liquor amount entrained in the gas hydrate after liquid separation by sinking was very high when surfactants was not added, but the equilibrium pressure of gas hydrate formation was decreased and the mother liquor amount entrained in gas hydrate was also decreased when surfactants was added to the system. In addition, the equilibrium pressure of gas hydrate formation in the quaternary system H2O-H2O2-CO(NH2)2-C3H8 was calculated according to Chen-Guo thermodynamic model, improved UNIFAC mathematical equation and Aasberg-Peterson fugacity coefficient model. The calculated data was in agreement with the experiment data.

APA, Harvard, Vancouver, ISO, and other styles

21

Paraíba, Lourival Costa, Vera Lúcia Scherholz Salgado de Castro, and Aline de Holanda Nunes Maia. "Insecticide distribution model in human tissues viewing worker's health monitoring programs." Brazilian Archives of Biology and Technology 52, no. 4 (2009): 875–81. http://dx.doi.org/10.1590/s1516-89132009000400011.

Full text

Abstract:

This work aimed at evaluating the characteristics of thirty nine insecticides on tissue distribution and accumulation, using their physico-chemical characteristics and the tissues lipid contents to calculate the compounds distribution among the tissues. The insecticides evaluated were selected among those registered in Brazil for agriculture use. The level I fugacity model was used for the calculations of insecticide distribution among the tissues of muscles, viscera, skin, fat, blood, liver, kidneys and gut. The octanol-water partition coefficient, water solubility and tissue lipid contents showed an insecticide distribution in human tissues. Cluster analysis was performed aiming the identification and separation of insecticides groups based on their physico-chemical characteristics as compounds with similar distribution within tissues and at the same time tissues with similar distribution of various insecticides. Cluster analysis pointed out three insecticide groups: in the first, 70 - 86% of insecticide accumulation was found in lipid tissues; in the second, 44 - 58%; and in the third, 9 -19%. These results could contribute to health monitoring programs of farmworkers.

APA, Harvard, Vancouver, ISO, and other styles

22

Chistyakov, A. D. "Fugacity coefficients for water vapor." Russian Journal of Physical Chemistry A 81, no. 4 (2007): 651–53. http://dx.doi.org/10.1134/s0036024407040267.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Bruno, Thomas J., and Stephanie L. Outcalt. "Fugacity coefficients of hydrogen in (hydrogen + butane)." Journal of Chemical Thermodynamics 25, no. 9 (1993): 1061–70. http://dx.doi.org/10.1006/jcht.1993.1103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Jin, Xiaoye, and Jixiang Sui. "Geochemistry of Tourmaline from the Laodou Gold Deposit in the West Qinling Orogen, Central China: Implications for the Ore-Forming Process." Minerals 10, no. 8 (2020): 647. http://dx.doi.org/10.3390/min10080647.

Full text

Abstract:

The Laodou gold deposit, located in the West Qinling Orogen of central China, is a newly recognized intrusion-related gold deposit. It consists of auriferous quartz-sulfide-tourmaline and minor quartz-stibnite veins that are structurally controlled by fault zones transecting the host quartz diorite porphyry. Two types of tourmaline were identified in this study: Type 1 tourmaline occurs as quartz-tourmaline nodules within the quartz diorite porphyry, whereas type 2 tourmaline occurs as quartz-sulfide-tourmaline veins in auriferous lodes. Here, we present a major and trace element analysis by electron microprobe and laser ablation inductively coupled plasma mass spectrometry on these two types of tourmaline. Both tourmaline types fall into the alkali group, and are classified under the schorl-dravite solid solution series. The substitutions of FeMg–1, FeAl–1, AlO((Fe, Mg)(OH)) –1, and X-site vacancyCa–1 are inferred by the variations of their major element compositions. Field and mineralogy observations suggest that type 1 tourmaline is a product of the late crystallization process of the quartz diorite porphyry, whereas type 2 tourmaline coexists with Au-bearing arsenopyrite and is crystallized from the ore-forming fluids. Their rare earth element compositions record the related magmatic hydrothermal evolution. The Co and Ni concentrations of the coexisting type 2 tourmaline and arsenopyrite define a regression line (correlation coefficient = 0.93) with an angular coefficient of 0.66, which represents the Co/Ni ratio of the tourmaline and arsenopyrite-precipitating fluids. This value is close to the Co/Ni ratios of the host quartz diorite porphyry, indicating a magma origin of the ore-forming fluids. The substitution of Al3+ by Fe3+ in both tourmaline types shows that type 1 tourmaline approaches the end member of povondraite whereas type 2 tourmaline occurs in opposite plots near the end member of Oxy-dravite, reflecting a more oxidizing environment for type 2 tourmaline formation. Moreover, the redox-sensitive V and Cr values of type 2 tourmaline are commonly 1–2 orders of magnitude higher than those of type 1 tourmaline, which also suggests that type 2 tourmaline forms from more oxidizing fluids. Combined with gold occurrence and fluid properties, we propose that the increasing of oxygen fugacity in the ore-forming fluids is a trigger of gold precipitation.

APA, Harvard, Vancouver, ISO, and other styles

25

Dong, Qian, Yangsong Du, Zhenshan Pang, Wenrui Miao, and Wei Tu. "Composition of biotite within the Wushan granodiorite, Jiangxi Province, China: Petrogenetic and metallogenetic implications." Earth Sciences Research Journal 18, no. 1 (2014): 39–44. http://dx.doi.org/10.15446/esrj.v18n1.40830.

Full text

Abstract:

<p>The Wushan skarn copper deposit is genetically associated with the Wushan granodiorite. In this study, we investigate the petrography and mineralogy of biotites within the Wushan granodiorite. We also determine the formation conditions of these biotites and discuss the significance of these minerals in terms of petrogenesis and mineralization. Electron microprobe analysis shows that biotites within the Wushan granodiorite are Magnesio-biotites that contain relatively high Mg and Ti concentrations and low Fe and Al concentrations. The ionic coefficient of Al<sup>VI</sup> in these biotites ranges from 0.03 to 0.19, with SFeO/(SFeO + MgO) ratios that range from 0.531–0.567 and MgO concentrations that range from 12.80–14.06 wt%. These results indicate that the Wushan granodiorite is an I-type granite. The Wushan biotites crystallized at temperatures (T) of 720°C–750°C, with oxygen fugacity (fO<sub>2</sub>) conditions of –11.6 to –12.5 and pressures (P) of 0.86–1.03 kb. These conditions are indicative of a crystallization depth (H) of 2.84–3.39 km. These data also indicate that the Wushan granodiorite developed under conditions of high temperature and high oxygen fugacity, suggesting that the Wushan granodiorite is prospective for magma-hydrothermal mineralization and that this granodiorite probably contributed to the formation of the Wushan skarn copper deposit.</p><p> </p><p><strong>Resumen</strong></p><p>El depósito de skarn cuprífero de Wushan está asociado genéticamente con la granodiorita de Wushan. En este estudio se investiga la petrografía y mineralogía de biotitas de la granodiorita de Wushan. Se determinan también las condiciones de formación de estas biotitas y se discute la significación de estos minerales en términos de petrogénesis y mineralización. Un análisis de microsonda a electrones muestra que las biotitas de la granodiorita de Wushan son biotitas de magnesio que contienen altas concentracionesrelativas de Mg y Ti y bajas de Fe y Al. El coeficiente icónico de AlVI en estas biotitas oscila entre 0,03 y 0,19, con índices SFeO/(SFeO + MgO) que oscilan entre 0,531-0,567 y concentraciones de MgO que van desde 12,80 a 14,06 wt%. Estos resultados indican que la granodiorita de Wushan es de granito tipo I. Las biotitas de Wushan se cristalizaron a temperaturas (T) de 720°C–750°C, con condiciones de fugacidad del oxígeno (fO2) de -11,6 a -12,5 y presión (P) de O,86 a 1,03 kb. Estas condiciones indican una profundidad de cristalización (H) de 2,84-3,39 kilómetros. Los datos también indican que la granodiorita de Wushan se desarrolló bajo condiciones de alta temperatura y alta fugacidad de oxigeno, lo que sugiere que la granodiorita de Wushan tiene potencial para la mineralización magmática-hidrotérmica y que esta granodiorita probablemente contribuyó a la formación del depósito de skarn cuprífero de Wushan.</p>

APA, Harvard, Vancouver, ISO, and other styles

26

Nentwich, Corina, Joschka Winz, and Sebastian Engell. "Surrogate Modeling of Fugacity Coefficients Using Adaptive Sampling." Industrial & Engineering Chemistry Research 58, no. 40 (2019): 18703–16. http://dx.doi.org/10.1021/acs.iecr.9b02758.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Wierzchowski, Scott J., and David A. Kofke. "Fugacity Coefficients of Saturated Water from Molecular Simulation." Journal of Physical Chemistry B 107, no. 46 (2003): 12808–13. http://dx.doi.org/10.1021/jp0351270.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Wierzchowski, S. J., and David A. Kofke. "Fugacity Coefficients of Saturated Water from Molecular Simulation." Journal of Physical Chemistry B 108, no. 26 (2004): 9375–76. http://dx.doi.org/10.1021/jp0483425.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Jollands, Michael C., Hugh St C. O'Neill, Andrew J. Berry, Charles Le Losq, Camille Rivard, and Jörg Hermann. "A combined Fourier transform infrared and Cr K-edge X-ray absorption near-edge structure spectroscopy study of the substitution and diffusion of H in Cr-doped forsterite." European Journal of Mineralogy 33, no. 1 (2021): 113–38. http://dx.doi.org/10.5194/ejm-33-113-2021.

Full text

Abstract:

Abstract. Single crystals of synthetic Cr-doped forsterite (Cr:Mg2SiO4) containing both Cr3+ and Cr4+ were partially hydroxylated in piston-cylinder apparatuses at 750–1300 ∘C and pressures from 0.5 to 2.5 GPa, with p(H2O) ≈Ptotal. The oxygen fugacity (fO2) was buffered by graphite-water, Ni–NiO, Re–ReO2, Fe2O3–Fe3O4 or Ag–Ag2O, and the silica activity (aSiO2) was buffered by powdered forsterite plus either enstatite (Mg2Si2O6), periclase (MgO) or zircon–baddeleyite (ZrSiO4–ZrO2). Profiles of OH content versus distance from the crystal edge were determined using Fourier transform infrared (FTIR) spectroscopy, and profiles of the oxidation state and coordination geometry of Cr were obtained, at the same positions, using K-edge X-ray absorption near-edge structure (XANES) spectroscopy. The techniques are complementary – FTIR spectroscopy images the concentration and nature of O–H bonds, where Cr K-edge XANES spectroscopy shows the effect of the added H on the speciation of Cr already present in the lattice. Profiles of defect-specific absorbance derived from FTIR spectra were fitted to solutions of Fick's second law to derive diffusion coefficients, which yield the Arrhenius relationship for H diffusion in forsterite: log⁡10D̃[001]=-2.5±0.6+-(224±12+4.0±2.0P)2.303RT, where D̃ is the measured diffusion coefficient in m2 s−1, valid for diffusion parallel to [001] and calibrated between 1000 and 750 ∘C, P and T are in GPa and K, and R is 0.008314 kJK−1 mol−1. Diffusivity parallel to [100] is around 1 order of magnitude lower. This is consistent with previous determinations of H diffusion associated with M-site vacancies. The FTIR spectra represent a variety of Cr-bearing hydrous defects, along with defects associated with the pure Mg–Si–O–H system. It is proposed that all of the defects can form by interaction between the dry lattice, including Cr3+ and Cr4+, and fully hydroxylated M-site vacancies. The initial diffusive wave of hydroxylation is associated with neither reduction nor oxidation of Cr but with Cr4+ changing from tetrahedral to octahedral coordination. Superimposed on the H diffusion and concomitant change in Cr4+ site occupancy, but at a slower rate, producing shorter profiles, is reduction of Cr4+ to Cr3+ and potentially of Cr4+ and Cr3+ to Cr2+. In addition, by comparing FTIR data to trace element contents measured by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), constraints can be placed on absorption coefficients used for converting absorbance to H2O contents – our data support either wavenumber- or defect-dependent values of absorption coefficients. We estimate absorption coefficients of between 60 200 and 68 200 L mol−1 cm−1 for OH− associated with octahedral Cr3+ and an M-site vacancy and 18 700 to 24 900 L mol−1 cm−1 for two OH− associated with octahedrally coordinated Cr4+ and a Si vacancy (i.e. a “clinohumite-type” point defect).

APA, Harvard, Vancouver, ISO, and other styles

30

Bruno, Thomas J., and Stephanie L. Outcalt. "Fugacity coefficients of hydrogen in (hydrogen + 2-methylpropane): pressure dependence." Journal of Chemical Thermodynamics 22, no. 9 (1990): 873–83. http://dx.doi.org/10.1016/0021-9614(90)90175-p.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Li, T. W., E. H. Chimowitz, and F. Munoz. "First-order corrections to infinite dilution fugacity coefficients using computer simulation." AIChE Journal 41, no. 10 (1995): 2300–2305. http://dx.doi.org/10.1002/aic.690411013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Bruno, T. J., J. A. Schroeder, and S. L. Outcalt. "Hydrogen component fugacity coefficients in binary mixtures with ethane: Pressure dependence." International Journal of Thermophysics 11, no. 5 (1990): 889–96. http://dx.doi.org/10.1007/bf00503581.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Bruno, T. J., and S. L. Outcalt. "Hydrogen-component fugacity coefficients in binary mixtures with isobutane: temperature dependence." International Journal of Thermophysics 11, no. 1 (1990): 109–17. http://dx.doi.org/10.1007/bf00503863.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Kaur, S., and B. P. Akhouri. "Predictions of fugacity coefficients of pure substances from equations of state." IOP Conference Series: Materials Science and Engineering 1091, no. 1 (2021): 012019. http://dx.doi.org/10.1088/1757-899x/1091/1/012019.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Orr, J. C., and J. M. Epitalon. "Improved routines to model the ocean carbonate system: mocsy 2.0." Geoscientific Model Development 8, no. 3 (2015): 485–99. http://dx.doi.org/10.5194/gmd-8-485-2015.

Full text

Abstract:

Abstract. Modelers compute ocean carbonate chemistry often based on code from the Ocean Carbon Cycle Model Intercomparison Project (OCMIP), last revised in 2005. Here we offer improved publicly available Fortran 95 routines to model the ocean carbonate system (mocsy 2.0). Both codes take as input dissolved inorganic carbon CT and total alkalinity AT, tracers that are conservative with respect to mixing and changes in temperature and salinity. Both use the same thermodynamic equilibria to compute surface-ocean pCO2 and simulate air–sea CO2 fluxes, but mocsy 2.0 uses a faster and safer algorithm (SolveSAPHE) to solve the alkalinity-pH equation, applicable even under extreme conditions. The OCMIP code computes only surface pCO2, while mocsy computes all other carbonate system variables throughout the water column. It also avoids three common model approximations: that density is constant, that modeled potential temperature is equal to in situ temperature, and that depth is equal to pressure. Errors from these approximations grow with depth, e.g., reaching 3% or more for pCO2, H+, and ΩA at 5000 m. The mocsy package uses the equilibrium constants recommended for best practices. It also offers two new options: (1) a recently reassessed total boron concentration BT that is 4% larger and (2) new K1 and K2 formulations designed to include low-salinity waters. Although these options enhance surface pCO2 by up to 7 μatm, individually, they should be avoided until (1) best-practice equations for K1 and K2 are reevaluated with the new BT and (2) formulations of K1 and K2 for low salinities are adjusted to be consistent among pH scales. The common modeling practice of neglecting alkalinity contributions from inorganic P and Si leads to substantial biases that could easily be avoided. With standard options for best practices, mocsy agrees with results from the CO2SYS package within 0.005% for the three inorganic carbon species (concentrations differ by less than 0.01 μmol kg−1). Yet by default, mocsy's deep-water fCO2 and pCO2 are many times larger than those from older packages, because they include pressure corrections for K0 and the fugacity coefficient.

APA, Harvard, Vancouver, ISO, and other styles

36

Li, Jun, Raheel Ahmed, and Xiaochun Li. "Thermodynamic Modeling of CO2-N2-O2-Brine-Carbonates in Conditions from Surface to High Temperature and Pressure." Energies 11, no. 10 (2018): 2627. http://dx.doi.org/10.3390/en11102627.

Full text

Abstract:

Nitrogen (N2) and oxygen (O2) are important impurities obtained from carbon dioxide (CO2) capture procedures. Thermodynamic modeling of CO2-N2-O2-brine-minerals is important work for understanding the geochemical change of CO2 geologic storage with impurities. In this work, a thermodynamic model of the CO2-N2-O2-brine-carbonate system is established using the “fugacity-activity” method, i.e., gas fugacity coefficients are calculated using a cubic model and activity coefficients are calculated using the Pitzer model. The model can calculate the properties at an equilibrium state of the CO2-N2-O2-brine-carbonate system in terms of gas solubilities, mineral solubilities, H2O solubility in gas-rich phase, species concentrations in each phase, pH and alkalinity. The experimental data of this system can be well reproduced by the presented model, as validated by careful comparisons in conditions from surface to high temperature and pressure. The model established in this work is suitable for CO2 geologic storage simulation with N2 or O2 present as impurities.

APA, Harvard, Vancouver, ISO, and other styles

37

Mizan, Tahmid I., Phillip E. Savage, and Robert M. Ziff. "Fugacity coefficients for free radicals in dense fluids: HO2 in supercritical water." AIChE Journal 43, no. 5 (1997): 1287–99. http://dx.doi.org/10.1002/aic.690430517.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Debenedetti, P. G., and S. K. Kumar. "Infinite dilution fugacity coefficients and the general behavior of dilute binary systems." AIChE Journal 32, no. 8 (1986): 1253–62. http://dx.doi.org/10.1002/aic.690320804.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Olivera-Fuentes, Claudio. "Multicomponent fugacity coefficients and residual properties from pressure-explicit equations of state." Chemical Engineering Science 46, no. 8 (1991): 2019–29. http://dx.doi.org/10.1016/0009-2509(91)80161-q.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Pásztor, Attila, Paolo Alba, Rene Bellwied, et al. "Hadron thermodynamics from imaginary chemical potentials." EPJ Web of Conferences 175 (2018): 07046. http://dx.doi.org/10.1051/epjconf/201817507046.

Full text

Abstract:

We use 4stout improved staggered lattice data at imaginary chemical potentials to calculate fugacity expansion coefficients in finite temperature QCD. We discuss the phenomenological interpretation of our results within the hadron resonance gas (HRG) model, and the hints they give us about the hadron spectrum. We also discuss features of the higher order coefficients that are not captured by the HRG. This conference contribution is based on our recent papers [1, 2].,

APA, Harvard, Vancouver, ISO, and other styles

41

Mei, Yuan, Weihua Liu, A. A. Migdiov, Joël Brugger, and A. E. Williams-Jones. "CuCl Complexation in the Vapor Phase: Insights from Ab Initio Molecular Dynamics Simulations." Geofluids 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/4279124.

Full text

Abstract:

We investigated the hydration of the CuCl0 complex in HCl-bearing water vapor at 350°C and a vapor-like fluid density between 0.02 and 0.09 g/cm3 using ab initio molecular dynamics (MD) simulations. The simulations reveal that one water molecule is strongly bonded to Cu(I) (first coordination shell), forming a linear [H2O-Cu-Cl]0 moiety. The second hydration shell is highly dynamic in nature, and individual configurations have short life-spans in such low-density vapors, resulting in large fluctuations in instantaneous hydration numbers over a timescale of picoseconds. The average hydration number in the second shell (m) increased from ~0.5 to ~3.5 and the calculated number of hydrogen bonds per water molecule increased from 0.09 to 0.25 when fluid density (which is correlated to water activity) increased from 0.02 to 0.09 g/cm3 (fH2O 1.72 to 2.05). These changes of hydration number are qualitatively consistent with previous solubility studies under similar conditions, although the absolute hydration numbers from MD were much lower than the values inferred by correlating experimental Cu fugacity with water fugacity. This could be due to the uncertainties in the MD simulations and uncertainty in the estimation of the fugacity coefficients for these highly nonideal “vapors” in the experiments. Our study provides the first theoretical confirmation that beyond-first-shell hydrated metal complexes play an important role in metal transport in low-density hydrothermal fluids, even if it is highly disordered and dynamic in nature.

APA, Harvard, Vancouver, ISO, and other styles

42

Frost, D. J., U. Mann, Y. Asahara, and D. C. Rubie. "The redox state of the mantle during and just after core formation." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 366, no. 1883 (2008): 4315–37. http://dx.doi.org/10.1098/rsta.2008.0147.

Full text

Abstract:

Siderophile elements are depleted in the Earth's mantle, relative to chondritic meteorites, as a result of equilibration with core-forming Fe-rich metal. Measurements of metal–silicate partition coefficients show that mantle depletions of slightly siderophile elements (e.g. Cr, V) must have occurred at more reducing conditions than those inferred from the current mantle FeO content. This implies that the oxidation state (i.e. FeO content) of the mantle increased with time as accretion proceeded. The oxygen fugacity of the present-day upper mantle is several orders of magnitude higher than the level imposed by equilibrium with core-forming Fe metal. This results from an increase in the Fe 2 O 3 content of the mantle that probably occurred in the first 1 Ga of the Earth's history. Here we explore fractionation mechanisms that could have caused mantle FeO and Fe 2 O 3 contents to increase while the oxidation state of accreting material remained constant (homogeneous accretion). Using measured metal–silicate partition coefficients for O and Si, we have modelled core–mantle equilibration in a magma ocean that became progressively deeper as accretion proceeded. The model indicates that the mantle would have become gradually oxidized as a result of Si entering the core. However, the increase in mantle FeO content and oxygen fugacity is limited by the fact that O also partitions into the core at high temperatures, which lowers the FeO content of the mantle. (Mg,Fe)(Al,Si)O 3 perovskite, the dominant lower mantle mineral, has a strong affinity for Fe 2 O 3 even in the presence of metallic Fe. As the upper mantle would have been poor in Fe 2 O 3 during core formation, FeO would have disproportionated to produce Fe 2 O 3 (in perovskite) and Fe metal. Loss of some disproportionated Fe metal to the core would have enriched the remaining mantle in Fe 2 O 3 and, if the entire mantle was then homogenized, the oxygen fugacity of the upper mantle would have been raised to its present-day level.

APA, Harvard, Vancouver, ISO, and other styles

43

MALLMANN, GUILHERME, RAÚL O. C. FONSECA, and ADOLFO B. SILVA. "An experimental study of the partitioning of trace elements between rutile and silicate melt as a function of oxygen fugacity." Anais da Academia Brasileira de Ciências 86, no. 4 (2014): 1609–29. http://dx.doi.org/10.1590/0001-3765201420140014.

Full text

Abstract:

Subduction zone or arc magmas are known to display a characteristic depletion of High Field Strength Elements (HFSE) relative to other similarly incompatible elements, which can be attributed to the presence of the accessory mineral rutile (TiO2) in the residual slab. Here we show that the partitioning behavior of vanadium between rutile and silicate melt varies from incompatible (∼0.1) to compatible (∼18) as a function of oxygen fugacity. We also confirm that the HFSE are compatible in rutile, with D(Ta)> D(Nb)>> (D(Hf)>/∼ D(Zr), but that the level of compatibility is strongly dependent on melt composition, with partition coefficients increasing about one order of magnitude with increasing melt polymerization (or decreasing basicity). Our partitioning results also indicate that residual rutile may fractionate U from Th due to the contrasting (over 2 orders of magnitude) partitioning between these two elements. We confirm that, in addition to the HFSE, Cr, Cu, Zn and W are compatible in rutile at all oxygen fugacity conditions.

APA, Harvard, Vancouver, ISO, and other styles

44

Fu, Peng, Ran Jia, Chui-Peng Kong, Roberts I. Eglitis, and Hong-Xing Zhang. "From determination of the fugacity coefficients to estimation of hydrogen storage capacity: A convenient theoretical method." International Journal of Hydrogen Energy 40, no. 34 (2015): 10908–17. http://dx.doi.org/10.1016/j.ijhydene.2015.07.005.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Kolset, Knut, and Anders Heiberg. "Evaluation of the ‘Fugacity' (FEQUM) and the ‘Exams' Chemical Fate and Transport Models: A Case Study on the Pollution of the Norrsundet Bay (Sweden)." Water Science and Technology 20, no. 2 (1988): 1–12. http://dx.doi.org/10.2166/wst.1988.0041.

Full text

Abstract:

Two different models have been used to investigate how chemicals present in wastewater from a kraft mill are transported and spread in an aquatic environment. The models, FEQUM (Fugacity EQUilibrium Model) and EXAMS, are presented, their characteristics explained and a comparison of the models is made. In FEQUM the concept of fugacity is considered as the driving force behind chemical transport. The EXAMS dispersion model uses water and sediment flow as the basis for calculating the dispersion of chemicals. FEQUM encompasses the whole environment, water, air, soil, sediments, suspended matter in water and biota, whereas EXAMS includes the aquatic domain only. Both models have been applied to the Norrsundet area. Norrsundet is a heavily polluted bay on the east coast of Sweden. The pollution is mainly due to a kraft mill located in the area. The models were calibrated using data on chloroform in wastewater and seawater, and then tested on four other pollutants present in the wastewater. Both models give satisfactory results for the compounds investigated, tetrachlorocatechol constituting the only exception. Correlation coefficients between calculated and measured concentrations vary from 0.86 to 0.97. The poor results obtained for tetrachlorocatechol are probably due to the especially high affinity of this compound for suspended particles.

APA, Harvard, Vancouver, ISO, and other styles

46

Soave, G., M. Barolo, and A. Bertucco. "Estimation of high-pressure fugacity coefficients of pure gaseous fluids by a modified SRK equation of state." Fluid Phase Equilibria 91, no. 1 (1993): 87–100. http://dx.doi.org/10.1016/0378-3812(93)85081-v.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Zhang, Ping, and Tong Liu. "Heat kernel approach for confined quantum gas." Modern Physics Letters A 35, no. 13 (2020): 2050100. http://dx.doi.org/10.1142/s021773232050100x.

Full text

Abstract:

In this paper, based on the heat kernel technique, we calculate equations of state and thermodynamic quantities for ideal quantum gases in confined space with external potential. Concretely, we provide expressions for equations of state and thermodynamic quantities by means of heat kernel coefficients for ideal quantum gases. Especially, using an analytic continuation treatment, we discuss the application of the heat kernel technique to Fermi gases in which the expansion diverges when the fugacity [Formula: see text]. In order to calculate the modification of heat kernel coefficients caused by external potentials, we suggest an approach for calculating the expansion of the global heat kernel of the operator [Formula: see text] based on an approximate method of the calculation of spectrum in quantum mechanics. We discuss the properties of quantum gases under the condition of weak and complete degeneration, respectively. Moreover, we give an expansion of the one-loop effective action in D-dimensional space.

APA, Harvard, Vancouver, ISO, and other styles

48

Jiménez, Cristian, Iván Amaya, and Rodrigo Correa. "Calculation and Prediction of Fugacity and Activity Coefficients in Binary Mixtures, using a Self-Regulated Fretwidth Harmony Search Algorithm." Revista Ingenierías Universidad de Medellín 16, no. 30 (2017): 67–96. http://dx.doi.org/10.22395/rium.v16n30a4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Petry, Christof, Sumit Chakraborty, and Herbert Palme. "Experimental determination of Ni diffusion coefficients in olivine and their dependence on temperature, composition, oxygen fugacity, and crystallographic orientation." Geochimica et Cosmochimica Acta 68, no. 20 (2004): 4179–88. http://dx.doi.org/10.1016/j.gca.2004.02.024.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Li, Jun, and Xiaochun Li. "Numerical Modeling of CO2, Water, Sodium Chloride, and Magnesium Carbonates Equilibrium to High Temperature and Pressure." Energies 12, no. 23 (2019): 4533. http://dx.doi.org/10.3390/en12234533.

Full text

Abstract:

In this work, a thermodynamic model of CO2-H2O-NaCl-MgCO3 systems is developed. The new model is applicable for 0–200 °C, 1–1000 bar and halite concentration up to saturation. The Pitzer model is used to calculate aqueous species activity coefficients and the Peng–Robinson model is used to calculate fugacity coefficients of gaseous phase species. Non-linear equations of chemical potentials, mass conservation, and charge conservation are solved by successive substitution method to achieve phase existence, species molality, pH of water, etc., at equilibrium conditions. From the calculated results of CO2-H2O-NaCl-MgCO3 systems with the new model, it can be concluded that (1) temperature effects are different for different MgCO3 minerals; landfordite solubility increases with temperature; with temperature increasing, nesquehonite solubility decreases first and then increases at given pressure; (2) CO2 dissolution in water can significantly enhance the dissolution of MgCO3 minerals, while MgCO3 influences on CO2 solubility can be ignored; (3) MgCO3 dissolution in water will buffer the pH reduction due to CO2 dissolution.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!