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Wang, Laurie Luo. "Excess enthalpies of binary and ternary mixtures." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/9457.
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The research work involved in this study can be described in two aspects: the experimental determination of excess enthalpies, H$\rm\sp{E},$ for some binary and ternary liquid mixtures; and a theoretical study of various approaches for the representation of experimental H$\rm\sp{E}$ data. To determine the excess enthalpies of desired systems, a series of calorimetric experiments have been carried out for 15 binary and six ternary mixtures with an LKB flow microcalorimeter. A new model, based on statistical thermodynamic principles, has been developed for representing and predicting the excess enthalpy of a ternary mixture from correlation of the H$\rm\sp{E}$ values of its constituent binaries. The analyses of experimental results were carried out with several solution models, such as the Flory theory model, an association model, the DISQUAC model, the NRTL model, the UNIQUAC model, and the model developed in this study. The applicability of the proposed model for predicting ternary H$\rm\sp{E}$ values was further investigated. In addition to the six ternary systems experimentally studied in this work, six more ternary systems were selected from the literature. For comparison, the same calculations were also carried out with the 3-parameter NRTL and 2-parameter UNIQUAC models.
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Zhang, Dingan. "Solid-supercritical fluid phase equilibria of binary and ternary mixtures." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5611.
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Experimental investigation of phase equilibria at supercritical fluid conditions was carried out for four binary mixtures and two ternary mixtures consisting of supercritical carbon dioxide and aromatic compounds (naphthalene, biphenyl, m-terphenyl and phenanthrene). A new technique, the first freezing point method, was developed in this study to determine the pressure-temperature (P-T) projection of the solid-liquid-gas (S-L-G) three-phase coexistence curves for binary and ternary mixtures at supercritical fluid conditions. In addition, the equilibrium liquid compositions along the three-phase coexistence curves were also determined. A temperature minimum in the P-T projection of the three-phase coexistence curve was observed for each of the binary mixtures. The liquid-gas (L = G) critical loci of two binary mixtures consisting of super-critical carbon dioxide and a solid (naphthalene or biphenyl) were determined. The bubble-point pressures along three isotherms as well as the solubilities of carbon dioxide in liquid naphthalene and biphenyl were also measured. By means of the intersection method, the upper critical end points (UCEP) were established to be 333.4 K, 25.9 MPa and 0.16 mole fraction of naphthalene for naphthalene-carbon dioxide mixture and 328.5 K, 48.5 MPa and 0.18 mole fraction of biphenyl for biphenyl-carbon dioxide mixture. A "crossover region" was found in the study of isothermal solubilities of super-critical CO$\sb2$ in liquid biphenyl at a pressure of about 36 MPa. Below the crossover region pressure, an increase in temperature caused a decrease in solubility of carbon dioxide in the liquid phase, while above the crossover region pressure the opposite effect occurs. A rational explanation was given. The P-T projection of the solid 1-solid 2-liquid gas (S$\sb1$-S$\sb2$-L-G) four-phase coexistence curve of two ternary mixtures--naphthalene-biphenyl-carbon dioxide and naphthalene-phenanthrene-carbon dioxide--were determined. The results indicate that the assumption of an unchanged eutectic composition of the solids with pressure may lead to a not negligible error in the measurements. The freezing point depression of the solid under the pressure of a supercritical solvent and the solubility behaviour in the vicinity of the lower critical end point (LCEP) and the UCEP were explored and discussed. The slopes of the depression curves at the triple points of the solids were predicted. Two different approaches, based respectively on the compressed gas model (equation of state) and the expanded liquid model (activity coefficient model), were developed to describe the S-L-G three-phase equilibria and the solubilities of supercritical carbon dioxide in the melted solids. Using the Peng-Robinson equation of state with the modified correction factors, $\alpha$, together with the composition-dependent mixing rules, the correlations of the experimental results were accomplished with satisfactory accuracy. The merits of these two approaches in the representation of the S-L-G three-phase equilibria were compared.
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Miller, Melanie Marie. "Multiphase equilibria behavior of carbon dioxide and ethane + hydrocarbon binary and ternary mixtures /." Access abstract and link to full text, 1988. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8825490.
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Khalil, Enam A. S. A. "A thermodynamic study of binary and ternary mixtures of some alkanes and alkanols." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328889.
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Lam, Daniel H. "Multiphase equilibrium behavior of ethane, nitrous oxide and carbon dioxide + n-alkanol binary and ternary mixtures /." Access abstract and link to full text, 1990. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9034205.
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Clements, Patricia J. "Critical point behaviour in binary and ternary liquid mixtures with particular reference to rheological and interfacial properties in model mixtures for microemulsions." Thesis, University of Sheffield, 1997. http://etheses.whiterose.ac.uk/10187/.
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The phase behaviour, rheological effects and interfacial properties of binary and ternary liquid mixtures have been studied near critical points. In particular, measurements have been made of the viscosity-at the bulk macroscopic level by capillary viscometry and at the microscopic level by fluorescence depolarisatiorr-and of critical-point wetting and adsorptiorr-at the solid-liquid interface using evanescent-wave-generated fluorescence spectroscopy and at the liquid-vapour interface using specular neutron reflection. The systems investigated have been mostly alkane + perfluoroalkane mixtures or 2-butoxyethanol + H20 or D20 mixtures, although in some cases hexamethyldisiloxane, propanenitrile and perfluorooctyloctane have also been the components of mixtures. The main outcomes of this study are: • Macroscopic viscosity: The divergence to infinity in the shear viscosity of hexane + perfluorohexane at the critical endpoint for approach along the path of constant critical composition both from the single phase and along both limbs of the coexistence curve is described well using the Renormalisation Group Theory critical exponent y = 0.04. The correlation length amplitude obtained by fitting the sheargradient dependence of the viscosity is ~o = (S.S±l.S) A. • Microscopic viscosity: The product of the rotational correlation time and the temperature 'tR"T, often taken as a measure of the microscopic viscosity, exhibits an anomaly as the critical point is approached as a function of temperature. This anomaly mirrors that in the macroscopic viscosity for some fluorescent dye probes, but for others the anomaly is in the opposite sense indicating that other effects such as solvent structure must playa part in the near-critical behaviour of'tR·T. • Critical-point wetting at the solid-liquid interface: The wetting transition temperature has been identified for heptane + perfluorohexane at the quartz-liquid interface from fluorescence lifetime measurements of a probe. The wetting layer is of the same composition as the bulk heptane-rich phase and the transition is tentatively identified as first-order. • Adsorption and wetting at the liquid-vapour interface: The surface structure of several mixtures has been determined by neutron reflection. The results are in general agreement with the expectations of critical-point wetting and adsorption. The surface is complex and in some mixtures an oscillatory scattering length density profile through the interface is required to model the reflectivity data. • Ternary mixtures: The phase behaviour of three mixtures exhibiting tunnel phase behaviour has been studied experimentally and various characteristics of the shape of the twmel identified. A theoretical study on one of the mixtures predicts the drop in temperature for the locus of maximum phase separation temperatures which is observed experimentally.
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Ponnuchamy, Veerapandian. "Towards A Better Understanding of Lithium Ion Local Environment in Pure, Binary and Ternary Mixtures of Carbonate Solvents : A Numerical Approach." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GRENY004/document.
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En raison de l'augmentation de la demande d'énergie, ressources écologiques respectueux de l'environnement et durables (solaires, éoliennes) doivent être développées afin de remplacer les combustibles fossiles. Ces sources d'énergie sont discontinues, étant corrélés avec les conditions météorologiques et leur disponibilité est fluctuant dans le temps. En conséquence, les dispositifs de stockage d'énergie à grande échelle sont devenus incontournables, pour stocker l'énergie sur des échelles de temps longues avec une bonne compatibilité environnementale. La conversion d'énergie électrochimique est le mécanisme clé pour les développements technologiques des sources d'énergie alternatives. Parmi ces systèmes, les batteries Lithium-ion (LIB) ont démontré être les plus robustes et efficaces et sont devenus la technologie courante pour les systèmes de stockage d'énergie de haute performance. Ils sont largement utilisés comme sources d'énergie primaire pour des applications populaires (ordinateurs portables, téléphones cellulaires, et autres). La LIB typique est constitué de deux électrodes, séparés par un électrolyte. Celui-ci joue un rôle très important dans le transfert des ions entre les électrodes fournissant la courante électrique. Ce travail de thèse porte sur les matériaux complexes utilisés comme électrolytes dans les LIB, qui ont un impact sur les propriétés de transport du ion Li et les performances électrochimiques. Habituellement l'électrolyte est constitué de sels de Li et de mélanges de solvants organiques, tels que les carbonates cycliques ou linéaires. Il est donc indispensable de clarifier les propriétés structurelles les plus importantes, et leurs implications sur le transport des ions Li+ dans des solvants purs et mixtes. Nous avons effectué une étude théorique basée sur la théorie du fonctionnelle densité (DFT) et la dynamique moléculaire (MD), et nous avons consideré des carbonates cyclique (carbonate d'éthylène, EC, et carbonate de propylène, PC) et le carbonate de diméthyle, DMC, linéaire. Les calculs DFT ont fourni une image détaillée des structures optimisées de molécules de carbonate et le ion Li+, y compris les groupes pures Li+(S)n (S =EC,PC,DMC et n=1-5), groupes mixtes binaires, Li+(S1)m(S2)n (S1,S2=EC,PC,DMC, m+n=4), et ternaires Li+(EC)l(DMC)m(PC)n (l+m+n=4). L'effet de l'anion PF6 a également été étudié. Nous avons aussi étudié la structure de la couche de coordination autour du Li+, dans tous les cas. Nos résultats montrent que les complexes Li+(EC)4, Li+(DMC)4 et Li+(PC)3 sont les plus stables, selon les valeurs de l'énergie libre de Gibbs, en accord avec les études précédentes. Les énergies libres de réactions calculés pour les mélanges binaires suggèrent que l'ajout de molécules EC et PC aux clusters Li+ -DMC sont plus favorables que l'addition de DMC aux amas Li+-EC et Li+-PC. Dans la plupart des cas, la substitution de solvant aux mélanges binaires sont défavorables. Dans le cas de mélanges ternaires, la molécule DMC ne peut pas remplacer EC et PC, tandis que PC peut facilement remplacer EC et DMC. Notre étude montre que PC tend à substituer EC dans la couche de solvation. Nous avons complété nos études ab-initio par des simulations MD d'une ion Li immergé dans les solvants purs et dans des mélanges de solvants d'intérêt pour les batteries, EC:DMC(1: 1) et EC:DMC:PC(1:1:3). MD est un outil très puissant et nous a permis de clarifier la pertinence des structures découvertes par DFT lorsque le ion est entouré par des solvants mélangés. En effet,la DFT fournit des informations sur les structures les plus stables de groupes isolés, mais aucune information sur leur stabilité ou de la multiplicité (entropie) lorsqu'il est immergé dans un environnement solvant infinie. Les données MD, ainsi que les calculs DFT nous ont permis de donner une image très complète de la structure locale de mélanges de solvants autour le ion lithium, sensiblement amélioré par rapport aux travaux précédents<br>Due to the increasing global energy demand, eco-friendly and sustainable green resources including solar, or wind energies must be developed, in order to replace fossil fuels. These sources of energy are unfortunately discontinuous, being correlated with weather conditions and their availability is therefore strongly fluctuating in time. As a consequence, large-scale energy storage devices have become fundamental, to store energy on long time scales with a good environmental compatibility. Electrochemical energy conversion is the key mechanism for alternative power sources technological developments. Among these systems, Lithium-ion (Li+) batteries (LIBs) have demonstrated to be the most robust and efficient, and have become the prevalent technology for high-performance energy storage systems. These are widely used as the main energy source for popular applications, including laptops, cell phones and other electronic devices. The typical LIB consists of two (negative and positive) electrodes, separated by an electrolyte. This plays a very important role, transferring ions between the electrodes, therefore providing the electrical current. This thesis work focuses on the complex materials used as electrolytes in LIBs, which impact Li-ion transport properties, power densities and electrochemical performances. Usually, the electrolyte consists of Li-salts and mixtures of organic solvents, such as cyclic or linear carbonates. It is therefore indispensable to shed light on the most important structural (coordination) properties, and their implications on transport behaviour of Li+ ion in pure and mixed solvent compositions. We have performed a theoretical investigation based on combined density Functional Theory (DFT) calculations and Molecular Dynamics (MD) simulations, and have focused on three carbonates, cyclic ethylene carbonate (EC) and propylene carbonate (PC), and linear dimethyl carbonate (DMC). DFT calculations have provided a detailed picture for the optimized structures of isolated carbonate molecules and Li+ ion, including pure clusters Li+(S)n (S=EC, PC, DMC and n=1-5), mixed binary clusters, Li+(S1)m(S2)n (S1, S2 =EC, PC, DMC, with m+n=4), and ternary clusters Li+(EC)l(DMC)m(PC)n with l+m+n=4. Pure solvent clusters were also studied including the effect of PF6- anion. We have investigated in details the structure of the coordination shell around Li+ for all cases. Our results show that clusters such as Li+(EC)4, Li+(DMC)4 and Li+(PC)3 are the most stable, according to Gibbs free energy values, in agreement with previous experimental and theoretical studies. The calculated Gibbs free energies of reactions in binary mixtures suggest that the addition of EC and PC molecules to the Li+-DMC clusters are more favourable than the addition of DMC to Li+-EC and Li+-PC clusters. In most of the cases, the substitution of solvent to binary mixtures are unfavourable. In the case of ternary mixtures, the DMC molecule cannot replace EC and PC, while PC can easily substitute both EC and DMC molecules. Our study shows that PC tends to substitute EC in the solvation shell. We have complemented our ab-initio studies by MD simulations of a Li-ion when immersed in the pure solvents and in particular solvents mixtures of interest for batteries applications, e.g. , EC:DMC (1:1) and EC:DMC:PC(1:1:3). MD is a very powerful tool and has allowed us to clarify the relevance of the cluster structures discovered by DFT when the ion is surrounded by bulk solvents. Indeed, DFT provides information about the most stable structures of isolated clusters but no information about their stability or multiplicity (entropy) when immersed in an infinite solvent environment. The MD data, together the DFT calculations have allowed us to give a very comprehensive picture of the local structure of solvent mixtures around Lithium ion, which substantially improve over previous work
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Beck, Lisa Elanna. "Diffusivity and resistance to deterioration from freezing and thawing of binary and ternary concrete mixture blends." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/8784.
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Master of Science<br>Department of Civil Engineering<br>Kyle Riding<br>Corrosion of reinforcing steel is one of the most common and serious causes of
reinforced concrete deterioration. While corrosion is normally inhibited by a passive layer that
develops around the reinforcing steel due to the high pH environment of the surrounding
concrete, chlorides will break down this protective layer, leading to reinforcement corrosion.
Decreasing the diffusivity of the concrete would slow the ingress of chlorides into concrete, and
is one of the most economical ways to increase the concrete service life.
Optimized concrete mixtures blending portland cement and supplementary cementing
materials (SCMs) have become popular throughout the construction industry as a method of
improving both fresh and long-term concrete properties such as workability, strength and
porosity. It has been shown that use of Class F fly ash, silica fume and ground granulated blast
furnace slag (GGBFS) in binary concrete mixture blends can result in a significant reduction in
concrete diffusivity. This study investigates the ability of Class C fly ash and ternary concrete
mixture blends to also aid in diffusivity reduction. In order to study the effect of incorporation of
SCMs into concrete, mixtures containing Class C and Class F fly ash, silica fume and GGBFS
were tested following the ASTM C 1556 procedures to measure the concrete’s apparent chloride
diffusivity. Structure life cycles were modeled using the measured apparent chloride
diffusivities with two finite-difference based life-cycle analysis software packages. To
determine whether a correlation between diffusivity and deterioration due to freezing and
thawing exists, samples were also tested for their ability to resist deterioration from freezing and
thawing cycles using a modified ASTM C 666 Procedure B test.
Results show that the use of Class C fly ash yields some service life improvements as
compared to the portland cement control mixtures, while ternary mixture blends performed
significantly better than the control mixture and equal to or better than the binary SCM mixtures
tested. Freeze-thaw tests showed all mixtures to be equally resistant to deterioration due to
freezing and thawing.
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Męcfel-Marczewski, Joanna. "Self Incompatible Solvent." Doctoral thesis, Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-201001195.
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In dieser Arbeit wird das neue Prinzip der „Selbstinkompatiblen Lösungsmittel“ vorgestellt. Es wird theoretisch abgeleitet, dass eine Mischung aus zwei Substanzen mit ungünstigen Wechselwirkungen bereitwillig eine weitere Substanz aufnehmen sollte, die diese ungünstigen Wechselwirkungen durch Verdünnen vermindert. Dies sollte umso stärker ausgeprägt sein, je ungünstiger die Wechselwirkungen zwischen den beiden ersten Substanzen sind. Da sich jedoch Substanzen mit sehr ungünstigen Wechselwirkungen physikalisch nicht mischen, entstand die Idee, diese Substanzen durch eine kovalente Bindung aneinander zu binden. Ein solches Molekül, das aus zwei inkompatiblen Hälften besteht, wird im Folgendem Selbstinkompatibles Lösungsmittel genannt. Die in dieser Arbeit gewählten Substanzen zeigen mäßige Inkompatibilität, deshalb ist ein Vergleich zwischen einfachen physikalischen Mischungen und kovalent verknüpften Molekülhälften noch möglich. Dieses Prinzip wird für binäre und ternäre Mischungen quantitativ berechnet und experimentell in drei Serien von Experimenten bestätigt: i) unter Verwendung von Lösungskalorimetrie und Bestimmung der Wechselwirkungsparameter zwischen Komponente 3 und einer bereits hergestellt physikalischen binären Mischung aus Komponente 1 und 2, ii) unter Verwendung von Lösungskalorimetrie und Bestimmung der Wechselwirkungsparameter zwischen Komponente 3 und den selbstinkompatiblen Losungsmitteln, die den in (i) gewählten Mischungen entsprechen und iii) aus der Sättigungslöslichkeit der Komponente 3 in den entsprechenden selbstinkompatiblen Lösungsmitteln. In diesen drei verschiedenen Messserien wird stets der gleichen Trend beobachtet: Die Selbstinkompatibilität eines Lösungsmittels begünstigt den Lösevorgang<br>In this thesis a new principle of Self Incompatible Solvent is introduced. It is shown theoretically that a preexisting mixture of two substances (compound 1 and 2) with unfavorable interactions will readily dissolve a third compound because it diminishes the unfavorable interaction between the compound 1 and 2 by dilution. This behavior should be the stronger the more unfavorable the interactions between compound 1 and 2 are. However, substances with strong unfavorable interactions will not mix. Therefore the idea pursued here is to enforce the desired preexisting mixture for example by linking compound 1 covalently to compound 2. Such a molecule that is composed of two incompatible parts is called Self Incompatible Solvent in this work. In this thesis examples of incompatible compounds that show moderate incompatibility are chosen, therefore it was possible to do a comparison between simple physical mixtures and covalently linked incompatible molecules. The theoretical prediction of the theory is compared with experiments. This principle is calculated quantitatively for binary and ternary mixtures and compared with the experimental results in three distinct series of experiments: i) by using solution calorimetry and calculation of the interaction parameters between compounds 3 and the preexisting binary mixture of compound 1 and 2, ii) by using solution calorimetry and calculation of the interaction parameters between compound 3 and the Self Incompatible Solvent that correspond to the mixtures used in (i) and iii) from the saturation solubility of compound 3 in the Self Incompatible Solvent. The results obtained from the theoretical prediction and these obtained from the three different series of experiments show the same trend: the self incompatibility of the solvent improves the dissolution process
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Wang, Yana. "Self-incompatible solvents with ionic groups." Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-107041.
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The concept of a self-incompatible solvent is introduced as a molecule composed of two parts (compound 1 and 2) with unfavourable interactions. A third compound will be readily dissolved in this solvent to diminish this unfavourable interaction by dilution. The more incompatible compounds 1 and 2 are, the stronger this behaviour is expected to be. In this work, ionic liquids comprising non-polar carbon chain and polar ionic group are chosen to serve as a model of self-incompatible solvent. The interactions parameters k of the ionic liquids with active ingredients are investigated to examine the effect of self-incompatibility of the ionic liquid molecule.
On the other hand, phase separation between compounds 1 and 2 will reduce the positive effect of self-incompatibility. The tendency of phase separation is increasing with increasing size of the two compounds. Thus, if compounds 1 and 2 are blocks tied together into a block copolymer, one expects a decreasing ability of the block copolymer to dissolve an active ingredient with increasing block length. In this work the ability of polybutadiene-block-poly(2-vinylpyridine) (PB-b-P2VP) block copolymers to dissolve the model compound anthracene is investigated. As expected, the solubility indeed decreases with increasing block length.
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Dunn, Patrick. "Binary mixtures near surfaces." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4216.
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This paper presents an approach to modeling a binary mixture near a surf ace. The approach used is based on statistical mechanics. The Cluster Variation (CV) method is used to solve an Ising-like model with a cluster size of two (neighboring lattice points). The free energy of the system is expressed in terms of the probabilities of occurrences of particular clusters. The CV method is first developed for a homogeneous system which leads to a set of three non-linear partial differential equations. The surface boundary is then introduced and the CV method is developed for this system which leads to a set of seven non-linear partial differential equations for each layer. In the calculations, the Natural Iteration (NI) method is introduced as a method of solving these non-linear partial differential equations. The steps involved in implementing the NI method are outlined. The number of layers is chosen to be 32. Concentration profiles are calculated for the binary system using the NI method and the results are discussed.
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Teng, I.-Lih. "Thermochemical Investigation of Ternary Nonelectrolyte Mixtures." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc500889/.
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Excess molar volumes have been determined for four ternary chlorobenzene + dibutyl ether + alkane mixtures at 25°C. Results of these measurements are used to test the applications and limitations of BAB, Redlich-Kister, Kohler and Hwang et al. cubic models. For the systems studied, Redlich- Kister, Kohler and Cubic models were found to provide reasonable predictions. Differences between experimental and predicted ΔV^ex_123 values were about ±0.020 cm^3mol^-1 or less at most ternary compositions. Solubilities are reported for anthracene in binary mixtures containing propanol and butanol with alkanes at 25°C. Results of these measurements are used to test the NIBS/Redlich-Kister expression. The three-parameter form of this expression is found to provide reasonable mathematical representation with deviations between experimental and back-calculated values being less than ±1%.
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Karanikas, Stelios. "Modelling of binary colliodal mixtures." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613809.
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Uguz, Kamuran Erdem. "Evaporative instability in binary mixtures." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112169/document.
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Cette étude concerne la physique des écoulements convectifs résultant d’une instabilité d’évaporation de fluides binaires. Ce problème a de nombreuses applications, l’enrobage par centrifugation, le dépôt de films, les caloducs, etc, pour lesquels le changement de phase et la convection jouent un rôle prépondérant dans la conception et la qualité des procédés. Le système physique étudié est un mélange liquide sous sa propre vapeur, confiné par deux plaques conductrices de chaleur et des bords latéraux isolants. Les plaques sont utilisées pour appliquer un gradient thermique. Aucun gradient de concentration n’est imposé au système. Ces gradients sont induits par les différentes vitesses d’évaporation des composés. Dans ce système, il est important de comprendre comment la dynamique des fluides et les transferts de masse et de chaleur entrent en compétition pour la formation de structures. Le principal objectif de ce travail est d’identifier les conditions pour que le système évolue d’un état conductif vers un état de convection lorsque le gradient vertical de température dépasse une certaine valeur critique.Dans le système, la convection s’installe par trois mécanismes distincts : évaporation, gradients de densité et gradients de tension interfaciale. Trois forces convectives s’opposent aux effets de diffusion qui tendent à garder le système en état conductif. Le seuil d’apparition de la convection dépend de quelques variables, comme les dimensions du contenant, les propriétés thermophysiques des phases liquide et vapeur, la fraction massique, et les caractéristiques de perturbations. L’effet de chacune de ces variables sur le seuil est étudié en présence ou non de gravité.Pour représenter la physique, un modèle mathématique non linéaire complet est développé, basé sur les conservations de quantité de mouvement, d’énergie et de masse dans chaque phase avec les conditions aux limites appropriées. Le fluide binaire est composé de deux alcools légers comme l’éthanol et le sec-butanol. Dans les équations du modèle, la masse volumique ainsi que la tension interfaciale sont fonctions à le fois de la température et de la concentration. Pour la recherche du seuil de transition, les équations sont linéarisées autour d’un état de base connu. Dans notre cas, il s’agit de l’état conductif. Le système d’équations linéaires résultant est résolu par une méthode de collocation spectrale Chebyshev.Nous obtenons quatre résultats principaux. Premièrement, dans un système multi-composants sans gravitation, une instabilité n’apparaît que lorsque le système est chauffé du côté de la phase vapeur contrairement à un système mono-composant. Cela implique que, si on souhaite éviter les instabilités, il vaut mieux un apport de chaleur par la phase liquide en cas de processus d’évaporation en couches minces ou en micro-gravité.Deuxièmement, en présence de gravité, un système multi-composants peut devenir instable quelle que soit la direction du chauffage. Si la convection thermique est négligeable, alors nous montrons que le chauffage par la phase vapeur est la configuration la plus instable. Sinon, les deux modes de chauffage sont à même de produire une instabilité. Ce résultat implique que le gradient thermique appliqué doit être inférieur à une valeur seuil pour éviter les instabilités quelle que soit la direction du chauffage.Troisièmement, lorsque l’instabilité apparaît en absence de gravité, des structures n’apparaitront pas dans le cas de fluide pur mais apparaitront dans le cas d’un fluide multi-composants. De même, des structures apparaitront en présence de gravité en fonction du facteur d’aspect du confinement. Les facteurs d’aspect peuvent être choisis pour éviter des structures multi-cellulaires même en cas d’apparition d’instabilités durant l’évaporation.Enfin, des structures oscillantes ne sont pas prédites de façon générale malgré les effets opposés des convections solutale et thermique dans le problème d’évaporation<br>This study focuses on understanding the physics of the convective flow resulting from evaporative instability in binary mixtures. This problem has wide applications in spin coating, film deposition, heat pipes, etc. where phase change and convection play a very important role in the design process and also final quality of the product. The physical system of interest consists of a liquid mixture underlying its own vapor sandwiched between two conducting plates with insulated sidewalls in a closed container. The conducting plates are used to apply a vertical temperature gradient while there is no applied concentration gradient in the system. Concentration gradients are induced by the different evaporation rate of the components. In this system it is important to understand how the fluid dynamics and the heat and mass transfer interact competitively to form patterns. The main goal of this work is to identify the conditions for the system going from the conductive no-flow state to a convection state when the applied vertical temperature gradient exceeds a certain value called the critical value.In the system convection arises due to three distinct phenomena; evaporation, density gradients, and interfacial tension gradients. These convective forces are opposed by the diffusion effects that try to keep the system in the conductive no-flow state. The onset point depends upon several variables such as the dimensions of the container, thermo-physical properties of both liquid and vapor phases, mass fraction, and the characteristic of the disturbance given to the system. The effects of each of these variables on the onset point are investigated both in the presence and in the absence of gravity. To represent the physics a complete non-linear mathematical model is developed including momentum, energy, and mass balances in both phases with appropriate boundary conditions. The binary mixture is assumed to be made up of two low weight alcohols such as ethanol and sec-butanol. In the modeling equations the density and the interfacial tension are taken to be function of both temperature and concentration. To identify the onset point the non-linear equations are linearized around a known base state. In this case the base state is the conductive no-flow state. The resulting set of linear equations is solved using a spectral Chebyshev collocation method. Four major results arise from this work. First, in a multi-component system in the absence of gravity, an instability arises only when the system is heated from the vapor side as opposed to evaporation in a single-component. The implication is that evaporative processes in thin layers or in micro-gravity are best conducted with heat from the liquid side if instabilities are to be avoided.Second, in the presence of gravity, a multi-component system may become unstable no matter the direction of heating. If thermal buoyancy is negligible then it is shown in this study that heating from the vapor side is the unstable arrangement. Otherwise either heating style can produce an instability. This result means that the applied temperature difference must be kept below a threshold in order to avoid flow instabilities no matter the heating direction.Third, whenever instability occurs in the absence of gravity, patterns will not result in the case of a pure component but may result in the case of multi-components. Likewise, patterns will result when gravity is taken into account provided the aspect ratio of the container lies in a suitable range. As a result, aspect ratios can be chosen to avoid multi-cellular patterns even if convective flow instabilities arise during evaporation.Lastly, oscillations are not ordinarily predicted despite opposing effects of solutaland thermal convection in the evaporation problem
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Monast, Patrick. "Wetting behavior of ternary mixtures containing surfactants." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ64410.pdf.
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Esselburn, Jason Dennis. "Porosity and Permeability in Ternary Sediment Mixtures." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1245949430.
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Siddons, Daniel James. "Synthetic routes to binary and ternary nitrides." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363637.
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Jung, Bumsuk. "Kinetics of phase separation in ternary polymer mixtures." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624370.
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Kessler, Cathie L. "Flashing sprays of binary hydrocarbon mixtures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0006/MQ45430.pdf.
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Di, Felice Renzo. "Liquid fluidisation of binary-solid mixtures." Thesis, University College London (University of London), 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362618.
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Bartle, Elizabeth Anne. "The polymorphism of binary lipid mixtures." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305427.
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Yip, Chiu-Wing. "Phase separation in binary polymer mixtures." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38202.
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Holesovsky, Ondrej. "Compact ConvNets with Ternary Weights and Binary Activations." Thesis, KTH, Robotik, perception och lärande, RPL, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-216389.
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Compact architectures, ternary weights and binary activations are two methods suitable for making neural networks more efficient. We introduce a) a dithering binary activation which improves accuracy of ternary weight networks with binary activations by randomizing quantization error, and b) a method of implementing ternary weight networks with binary activations using binary operations. Despite these new approaches, training a compact SqueezeNet architecture with ternary weights and full precision activations on ImageNet degrades classification accuracy significantly more than when training a less compact architecture the same way. Therefore ternary weights in their current form cannot be called the best method for reducing network size. However, the effect of weight decay on ternary weight network training should be investigated more in order to have more certainty in this finding.<br>Kompakta arkitekturer, ternära vikter och binära aktiveringar är två metoder som är lämpliga för att göra neurala nätverk effektivare. Vi introducerar a) en dithering binär aktivering som förbättrar noggrannheten av ternärviktsnätverk med binära aktiveringar genom randomisering av kvantiseringsfel, och b) en metod för genomförande ternärviktsnätverk med binära aktiveringar med användning av binära operationer. Trots dessa nya metoder, att träna en kompakt SqueezeNet-arkitektur med ternära vikter och fullprecisionaktiveringar på ImageNet försämrar klassificeringsnoggrannheten betydligt mer än om man tränar en mindre kompakt arkitektur på samma sätt. Därför kan ternära vikter i deras nuvarande form inte kallas bästa sättet att minska nätverksstorleken. Emellertid, effekten av weight decay på träning av ternärviktsnätverk bör undersökas mer för att få större säkerhet i detta resultat.
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Deng, Tʻai-ho. "Thermodynamic Properties of Nonelectrolyte Solutes in Ternary Solvent Mixtures." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc279275/.
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The purpose of this dissertation is to investigate the thermodynamic properties of nonelectrolyte solutes dissolved in ternary solvent mixtures, and to develop mathematical expressions for predicting and describing that behavior in the solvent mixtures. Thirty-four ternary solvent systems were studied containing either alcohol (1-propanol, 2-propanol, 1-butanol, and 2-butanol), alkane (cyclohexane, heptane, and 2,2,4-trimethylpentane) or alkoxyalcohol (2-ethoxyethanol and 2-butoxyethanol) cosolvents. Approximately 2500 experimental measurements were performed. Expressions were derived from the Combined Nearly Ideal Multiple Solvent (NIMS)/Redlich-Kister, the Combined Nearly Ideal Multiple Solvent (NIMS)/Bertrand, Acree and Burchfield (BAB) and the Modified Wilson models for predicting solute solubility in ternary solvent (or even higher multicomponent) mixtures based upon the model constants calculated from solubility data in sub-binary solvents. Average percent deviation between predicted and observed values were less than 2%, documenting that these models provide a fairly accurate description of the thermodynamic properties of nonelectrolyte solutions. Moreover, the models can be used for solubility prediction in solvent mixtures in order to find the optimum solvent composition for solubilization or desolubilization of a solute. From a computational standpoint, the Combined Nearly Ideal Multiple Solvent/Redlich-Kister equation is preferred because the needed model constants can be calculated with a simple linear regressional analysis. Model constants for the Modified Wilson equation had to be calculated using a reiterative trial-and-error method. The C++ program for the Modified Wilson equation applied to ternary and heptanary solvent mixtures is attached.
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Leung, Ki Y. "Electron mobilities in binary rare gas mixtures." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29339.
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This thesis presents a detailed study of the composition dependence of the thermal and transient mobility of electrons in binary rare gas mixtures. The time independent electron real mobility in binary inert gas mixtures is calculated versus mole fraction for different electric
field strengths. The deviations from the linear variation of the reciprocal of the mobility of the mixture with mole fraction, that is from Blanc's law, is determined and explained in detail. Very large deviations from the linear behavior were calculated for several binary mixtures at specific electric strengths, in particular for He-Xe mixtures. An interesting effect was observed whereby the electron mobility in He-Xe mixtures, for particular compositions and electron field strength could be greater than in pure He or less than in pure Xe.
The time dependent electron real mobility and the corresponding relaxation time, in particular for He-Ar and He-Ne mixtures are reported for a wide range of concentrations, field strengths (d.c. electric field), and frequencies (microwave electric field). For a He-Ar mixture, the time dependent electron mobility is strongly influenced by the Ramsauer-Townsend minimum and leads to the occurrence of an overshoot and a negative mobility in the transient mobility. For He-Ne, a mixture without the Ramsauer-Townsend minimum, the transient mobility increases monotonically towards the thermal value. The energy thermal relaxation times 1/Pτ for He-Ne, and Ne-Xe mixtures are calculated so as to find out the validity of the linear relationship between the 1/Pτ of the mixture and mole fraction. A Quadrature Discretization Method of solution of the time dependent Boltzmann-Fokker-Planck equation for electrons in binary inert gas mixture is employed in the study of the time dependent electron real mobility. The solution of the Fokker-Planck equation is based on the expansion of the solution in the eigenfunctions of the Fokker-Planck operator.<br>Science, Faculty of<br>Chemistry, Department of<br>Graduate
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Bettencourt, David G. "Lattice model for binary water-surfactant mixtures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0018/MQ27483.pdf.
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Parghi, Deven D. "Antiferroelectric liquid crystals : hosts and binary mixtures." Thesis, University of Hull, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397062.
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Cook, Graham David. "Mechanical strength of compacts of binary mixtures." Thesis, University College London (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284015.
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Jivani, Saqib Raza. "Investigation of Marangoni condensation of binary mixtures." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/54058.
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It is a well-known phenomenon that during Marangoni condensation of binary mixtures, a small concentration of more volatile constituent with smaller surface tension gives significant heat transfer enhancements. This is due to surface tension gradients causing instability in condensate film, resulting in a pseudo-dropwise mode of condensation which resembles closely to dropwise condensation of pure fluid on the hydrophobic surface, consequently, the film gets thinner with lower thermal resistance across the condensate film and thus higher heat transfer coefficient is achieved. Marangoni condensation of steam-ethanol mixtures has been widely investigated in the past. However, Marangoni condensation of self-rewetting fluids e.g. steam-butanol is yet to be investigated where the constituent in a small concentration is a less volatile component. Marangoni condensation of steam-ethanol, steam-butanol and steam-propanol mixtures has been investigated on a horizontal smooth tube at an atmospheric pressure. For all experiments, concentrations by mass in the boiler feed when cold prior to start of the experiment were 0.001%, 0.005%, 0.01%, 0.025%, 0.05%, 0.1%, 0.5% and 1.0%. The coolant temperature rise was measured accurately with a ten-junction thermopile. Tube wall temperature was measured using four thermocouples embedded in the test tube wall. Effects of pressure and vapour velocity over a wide range of vapour-to-surface temperature difference have been investigated. Care was taken to avoid error due to the presence of air in the vapour. Marangoni condensation of steam-butanol and steam propanol mixtures show significant heat transfer enhancements compared with that of steam-ethanol mixtures. Higher Heat flux and heat-transfer coefficients were observed. For the steam-ethanol mixtures, enhancement ratio (heat flux or heat-transfer coefficient divided by the corresponding value for pure steam condensation on a horizontal smooth tube for the same vapour-to-surface temperature difference and vapour velocity) of 5.5 was found at an ethanol concentration of 0.01%. For steam-butanol mixtures, the maximum enhancement ratio was found to be 11 at a concentration of 0.005% and 0.01%. For steam-propanol mixtures, the maximum enhancement ratio of 8.5 was found at the same mass concentrations as steam-butanol mixtures. Enhancement ratio was generally higher at lower ethanol concentrations, increases at first with increasing vapour-to-surface temperature difference and subsequently decreases at high vapour-to-surface temperature difference. Finally, a semi-empirical model was proposed to predict the Marangoni condensation of steam-ethanol mixtures based on the vapour phase diffusion theory of Sparrow and Marchall (1969) and pure steam dropwise theory of Rose (2002).
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Bribesh, Fathi. "Free surface films of binary liquid mixtures." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9810.
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Model-H is used to describe structures found in the phase separation in films of binary liquid mixture that have a surface that is free to deform and also may energetically prefer one of the components. The film rests on a solid smooth substrate that has no preference for any component. On the one hand the study focuses on static aspects by investigating steady states that are characterised by their concentration and film height profiles. A large variety of such states are systematically analysed by numerically constructing bifurcation diagrams in dependence of a number of control parameters. The numerical method used is based on minimising the free energy functional at given constraints within a finite element method for a variable domain shape. The structure of the bifurcation diagrams is related to the symmetry properties of the individual solutions on the various branches. On the other hand the full time dependent model-H is linearised about selected steady states, in particular, the laterally invariant, i.e.\ layered states. The resulting dispersion relations are discussed and related to the corresponding bifurcation points of the steady states. In general, the results do well agree and confirm each other. The described analysis is performed for a number of important cases whose comparison allows us to gain an advanced understanding of the system behaviour: We distinguish the critical and off-critical case that correspond to zero and non-zero mean concentration, respectively. In the critical case the investigation focuses on (i) flat films without surface bias, (ii) flat films with surface bias, (iii) height-modulated films without surface bias, and (iv) height-modulated films with surface bias. Each case is analysed for several mean film heights and (if applicable) energetic bias at the free surface using the lateral domain size as main control parameter. Linear stability analyses of layered films and symmetry considerations are used to understand the structures of the determined bifurcation diagrams. For off-critical mixtures our study is more restricted. There we consider height-modulated films without and with surface bias for several mean film heights and (if applicable) energetic bias employing the mean concentration as main control parameter.
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Izzo, Maria Grazia. "High frequency dynamics of fluid binary mixtures." Doctoral thesis, Università degli studi di Trieste, 2010. http://hdl.handle.net/10077/3585.
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2008/2009<br>This thesis is aimed to the study of dynamics in binary fluid mixtures by means of inelastic scattering spectroscopies.
Nowadays the understanding of these dynamics is still unsatisfactory. In particular, any model is able to adequately describe collective dynamics beyond the hydrodynamic limit. In such a low momentum (k) and frequency () transfer limit, the collective dynamics is characterized by a single (adiabatic) longitudinal acoustic mode accounting for sound propagation. At frequencies above the hydrodynamics ones a transition towards a decoupled dynamic regime is expected. This is characterized by two distinct modes, namely the slow (low-) and fast (high-) sounds. The microscopic mechanisms driving such a transition, so as the related macroscopic quantities, are still unclear, even in an heuristic point of view. In this work the collective dynamics of neutral and ionic mixtures are investigated with the aim to shed light in this debated issue.
He/Ne mixtures have been studied by means of Inelastic X-ray Scattering (IXS) spectroscopy. Exploiting the lack of kinematic limitations peculiar of this technique, the high frequency (>THz) dynamics has been analyzed from the mesoscopic up to the high-k range, where the dynamic response of the system can be described using the Impulse Approximation (IA). This kind of study is of particular interest for disparate mass mixtures, since inefficient kinetic energy exchanges between light and heavy particles taking place on very short time scales are expected to greatly influence the phenomenology of the aforementioned dynamic decoupling. The prototype ionic mixture, RbF, also, has been investigated by means of Inelastic Neutron Scattering (INS) spectroscopy. Ionic mixtures are particularly suited to investigate the role played by optic-like excitations (related to concentration fluctuations) in the transition from the hydrodynamics to the decoupled regime. Indeed, these kind of excitations are expected to be emphasized because of the long range Coulomb interactions. Conversely at k’s enough high, i.e. k>k* with k* dependent on the values of the electric conduction coefficient and the adiabatic sound velocity, they are expected to behave like neutral binary mixtures. The study of molten RbF has been, then, focused on the characterization of collective dynamics in the transition region, which is more difficultly accessible by IXS because of instrumental limitations.
IXS data on He0.8Ne0.2 mixture have been analyzed using a generalization of the viscoelastic function, which, in our knowledge, has been applied for the first time to this purpose. This kind of data analysis permitted to extrapolate the partial dynamical structure factors related to He-He, Ne-Ne and He-Ne density fluctuations. The adiabatic and high frequency sound velocity as well as the relaxation time associated to each mixture component has been calculated from fitting parameters. The analysis of the extrapolated relaxation times permitted to define, in the probed range, two k-region depending on the behavior of such quantity. At the higher k probed the relaxation times of single components can be well described by the respective single specie collision time, indicating a complete dynamics decoupling. At lower k, conversely, the relaxation times show a deviation to respect the collisional times. The study of the same mixture in three different thermodynamic conditions, revealed a common k trend of the single component relaxation times once proper normalization, made by means of kinetic parameters, has been done. An empirical expression has then been proposed. The result can be interpreted in the framework of ‘two temperature theory’, based on the assumption that in disparate mass binary mixtures inefficient kinetic energy exchanges induce a two step process for the relaxation of density fluctuations towards the thermodynamic equilibrium. These processes are characterized by two distinct timescales: the intra-specie collision time, where each specie subsystem reaches a condition of ‘local’ equilibrium associated with a ‘local’ temperature and a characteristic time for the equilibration of the microscopic temperatures to the thermodynamic temperature trough inter-specie collisions. A further corroboration of the above picture has been found from the analysis of IXS spectra in the IA region, which allowed extrapolating the momentum distribution functions of the specie subsets. An anomalous behavior has been noticed on the He momentum distribution function, i.e. the apparent temperature associated to the momentum distribution is about 40 K higher than the macroscopic one. This striking result can be straightforwardly interpreted as a fingerprint of the peculiar ‘two temperature’ equilibration process.
INS experiment on molten RbF permitted to reveal the simultaneous presence of two dispersive collective modes in the transition region. The dispersive behavior (linear with k) and the characteristic energies permitted to exclude an optic-like nature for both excitations. The performed data analysis permitted also to extrapolate the value of the electrical conduction coefficient, founding a quite low value as compared with typical values of molten salts. An estimation of k* for the studied system emphasize the possibility that at the probed k it may be isomorphous to a neutral mixture. The observed phenomenology can be thus interpreted in terms of double sound propagation phenomenon, observed in rarefied non-ionic gaseous mixtures. Finally, an alternative interpretation of these experimental results can be qualitatively provided within the frame of the generalized collective mode approach. In this case the high frequency mode is identified with the extension of the adiabatic longitudinal sound mode beyond hydrodynamic limit that, in analogy to what observed in several fluids, follows a linear dispersion with an associated sound velocity larger than the adiabatic one. The low frequency mode could instead be associated with a propagating kinetic mode related to energy fluctuations (heat waves).
In conclusion, an extensive analysis of high-frequency dynamics in binary mixtures has been reported. Particular emphasis has been devoted to the study of the sound decoupling phenomenon manifesting beyond the hydrodynamic region. The experimental results indicate that such a phenomenon is manifested in both neutral and ionic disparate mass binary mixtures. It can be related to microscopic dynamics, e.g. thermalization effects related to the inefficient kinetic exchange between lighter and heavier particles.<br>XXI Ciclo<br>1978
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Sarkar, Sudipta Kumar. "Phase transition in Binary Liquid Crystalline Mixtures." Thesis, University of North Bengal, 2017. http://hdl.handle.net/123456789/2674.
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O'Meara, Paul Martin. "The synthesis and characterisation of binary and ternary nitrides." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311740.
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Dyson, Heather Margaret. "Early hydration in binary and ternary blended cement systems." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422065.
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Treuel, Lennart. "On the phase behavior of binary and ternary aerosols." Berlin mbv, 2008. http://d-nb.info/993935699/04.
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Neyt, Jean-Claude. "Calcul de la tension interfaciale de mélanges gaz / eau, gaz / huile et huile / eau par simulation moléculaire." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-00962483.
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La prédiction de valeurs de tension interfaciale des fluides est capitale dans de nombreuses applications industrielles. Les techniques de simulation moléculaire et l'évolution rapide des moyens de calcul intensif permettent depuis quelques années de prédire des valeurs de tension interfaciale pour des systèmes complexes. Des travaux concernant des équilibres liquide / vapeur des corps purs SO2, O2, N2 et Ar montrent que les modèles choisi pour chaque molécule peuvent influencer la qualité des prédictions de tension interfaciale. Des simulations d'équilibres gaz acide / alcane de type CO2 / n-butane, CO2 / n-décane et H2S / n-pentane ont ensuite été réalisées. Elles ont mis en évidence l'efficacité des méthodes de simulation de type Monte Carlo pour la prédiction des tensions interfaciales pour de tels systèmes. L'étude de systèmes ternaires H2O / N2+CH4 et H2O / CO2+H2S a par ailleurs montré que le recourt à la dynamique moléculaire pouvait faciliter l'équilibration des systèmes simulés, rendant plus efficace la prédiction des tensions interfaciales. L'étude d'équilibres liquide / vapeur de saumures de chlorure de sodium a permis de mettre en évidence l'efficacité de certains potentiels non-polarisables pour la prédiction de l'évolution de la tension interfaciale avec la molarité de sel. Les modèles polarisables de type core-shell choisis ne permettent de prédire ni les masses volumiques, ni les tensions interfaciales. Enfin, l'étude d'équilibres eau / alcane en présence de sel ou de méthanol a montré que les méthodes de dynamique moléculaire permettaient de prédire quantitativement des valeurs de tension interfaciale pour ce type d'interface. L'effet de l'alcool abaissant la tension interfaciale a bien été observé, tout comme son placement préférentiel à l'interface.
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Laradji, Mohamed. "Ternary mixtures of water, oil and surfactants : equilibrium and dynamics." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39483.
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The equilibrium phase behaviour of ternary mixtures of water, oil and surfactants is examined using both a lattice-gas model and a Ginzburg-Landau model. The lattice model is based on the Blume-Capel model with additional orientational degrees of freedom for surfactants, and the Ginzburg-Landau model is based on two local scalar fields. When the concentrations of water and oil are equal the following phases are observed: a water and oil rich phase, a lamellar phase, and a disordered phase which is divided into an ordinary disordered fluid and a microemulsion region. In the lattice model, a square phase is also observed. The effects of fluctuations on the lattice model is studied via Monte-Carlo simulations and by the Langevin approach in the Ginzburg-Landau model. In both cases, we found that in the vicinity of the water/oil coexistence region, the lamellar phase becomes unstable against the microemulsion.<br>Furthermore, we have studied the effects of surfactants on the dynamics of phase separation of two immiscible fluids, and found a drastic alteration in the kinetics. In particular, we found that surfactants slow down the growth to a non-algebraic one leading eventually to a microphase separation.
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Bouzid, Assil. "First-principles investigation of binary and ternary amorphous chalcogenide systems." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAE029/document.
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Ce travail de thèse s’inscrit dans le cadre d'études théoriques ayant pour but l’établissement de la structure des chalcogénures binaires et ternaires sous différentes conditions thermodynamiques. Des techniques de modélisation numérique ab-initio ont été employées. En particulier, nous avons utilisé la dynamique moléculaire par premiers principes selon l’approche de Car et Parrinello ainsi que sa version dite "deuxième génération". La première partie est consacrée à l’étude des chalcogénures binaires, notamment les verres GeSe2 et GeSe4 sous pression ainsi qu'à l’étude des effets des forces de van der Waals et des fonctionnelles d’échange et corrélation DFT sur la structure de l’amorphe GeTe4. Dans la deuxième partie, l’intérêt a été porté à l’étude d'un matériau à changement de phase récemment proposé par les expérimentateurs comme un bon candidat pour le stockage de données, le ternaire Ga4Sb6Te3<br>This thesis reflects efforts toward an accurate understanding of the atomic scale structure of chalcogenide glasses. These compounds have an impact on electronics, optoelectronics and memory devices. I resorted to the most advanced first-principles molecular dynamics simulations such as the standard Car-Parrinello method as well as its second generation version. In the first part of this thesis we provide a detailed study of the topological changes undergone under pressure by glassy GeSe2 and by glassy GeSe4. Structural transition and bonding features are described and compared to the results of neutron and X-ray diffraction experiments. Furthermore, in the case of glassy GeTe4 we demonstrated that the inclusion of van der Waals forces leads to substantial improvements in the description of the structure. In the second part of this thesis, we established the atomic-scale organization of a promising candidate for phase change memory applications, glassy Ge4Sb6Te3
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Aas, Wenche. "Constitution, dynamics and structure of binary and ternary actinide complexes." Doctoral thesis, Stockholm, 1999. http://www.lib.kth.se/abs99/aas0329.pdf.
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Li, Yan, and 李彦. "Properties of mortars with binary and ternary blended cementitious materials." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48330097.
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During the past few decades, concrete technology has been developing rapidly followed with huge popularity of high-performance concrete (HPC). However, the mix design for HPC still remains a major challenge due to the wide adoption of mineral and chemical admixtures, the effects of which are rather complicated and not yet fully understood. To resolve this issue, this thesis presents a comprehensive experimental study focused on the physical effects of some supplementary cementitious materials (SCM) on the fresh and hardened properties of mortar. Based on the experimental results, some fundamental parameters governing the performance of mortar were investigated.
It has been postulated by some researches that increasing the packing density of the particle system would improve the rheology and strength of concrete. Through adding SCM finer than cement to increase the packing density, the voids between solid particles will be reduced so that more excess water can be released to provide better lubrication. Through adding two kinds of SCMs with different fineness, the packing density will be further enhanced by the successive filling action. In this study, a wet packing method, which is newly developed at the University of Hong Kong, was used to directly measure the packing densities of mortars with binary and ternary blended cementitious materials. The filling effect and successive filling action were both quantified through the packing density results.
The study revealed that the addition of fine SCM will, not only increase the packing density, but also increase the solid surface area, which will have negative effect on the rheology of mortar. To combine the effects of water content, packing density and solid surface area together, we proposed a new parameter called water film thickness (WFT), defined as the average thickness of water films coating the solid particles and evaluated as the excess water to solid surface area ratio. The results demonstrated that the WFT plays a key role in controlling the rheology and strength of mortar. Hence, it is the WFT, rather than the packing density, that should be maximized at given water content in the mix design of HPC. The addition of fine SCM will increase both the excess water content and solid surface area. The effects on the both sides can be quantified by the WFT no matter how complex the cementitious system is. Therefore, the WFT could be used as an effective indicator to adjust the SCM content. Joint addition of fine SCM at different level finer than cement to make a ternary cementitious system can effectively increase the packing density without excessively increasing the solid surface area. As a result, the ternary cementitious system has higher effectiveness than the binary cementitious system in improving the performance of mortar.<br>published_or_final_version<br>Civil Engineering<br>Master<br>Master of Philosophy
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Dzubiella, Joachim. "Phase behavior and structure of binary colloidal mixtures." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965561062.
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Cooney, Anthony M. "Thermodynamic properties of binary liquid mixtures containing fluoroalcohols." Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/34062.
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A detailed investigation into the thermodynamic properties of pure fluoroalcohols and binary mixtures containing fluoroalcohols is described. A batch calorimeter was used to measure excess enthalpies over the complete composition range and enthalpies of solution were obtained using an L.K.B. 8700 calorimeter. The excess volumes were determined using both batch and dilution dilatometers. Vapour-liquid equilibrium diagrams for binary mixtures have been determined from vapour pressure measurements using a static vapour pressure apparatus. Enthalpies of vaporisation of the fluoroalcohols were determined from the variation of the vapour pressure with temperature. Solid-liquid equilibrium phase diagrams have been determined using a simple freezing point cell, and liquid-liquid measurements obtained using a synthetic method. A new isothermal dilution calorimeter is also described. Unlike the batch calorimeter it allows a wide composition range to be studied from a single loading. The results for the test systems benzene + cyclo- hexane and benzene + tetrachloromethane obtained with this calorimeter are presented. The results obtained are in excellent agreement with those obtained by other workers.
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Jackson, Philip R. "Thermodynamic studies of binary mixtures involving aromatic fluorocarbons." Thesis, University of Leicester, 1986. http://hdl.handle.net/2381/33750.
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Solid-liquid phase diagrams have been determined for binary systems of hexafluorobenzene + naphthalene-type compounds, and indicate strong 1:1 congruently melting point complexes. Hexafluorobenzene + cis- and + trans-deca1in were found to give simple eutectic phase diagrams. Excess enthalpies, excess volumes and excess Gibbs functions have been measured for the same hexaf1uorobenzene + naphthalene-type compound mixtures and are large and negative, which is characteristic of systems where specific interactions take place. This contrasts with the large positive excess functions found with hexafluorobenzene + decalin systems, where only dispersion forces are assumed present. The excess Gibbs function for hexafluorobenzene + trans- and cis-decalin have been determined theoretically from freezing point data as well as directly from vapour pressure measurements. A batch calorimeter, besides being used for excess enthalpy measurememts, has been employed in determining heats of solution, which lead to a value for the enthalpy change for the process, solid + solid ? complex. The possibility of charge-transfer interactions occuring in hexafluorobenzene + naphthalene-type compound systems has been discussed in terms of HOMO/LUMO overlap considerations and is supported by the observation that pentafluorocyanobenzene forms stronger (higher melting point) complexes with 1- and 2-methylnaphthalene, than hexafluorobenzene does.
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Kojima, Takehiro. "Bulk flow properties of fine binary powder mixtures." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648838.
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Berti, Stefano. "Non-Newtonian turbulence : viscoelastic fluids and binary mixtures." Nice, 2006. http://www.theses.fr/2006NICE4079.
Full textAbstract:
Cette thèse présente une étude théorique et numérique de la turbulence dans les fluides non-Newtoniens, dont la dynamique peut être modélisée en termes du transport de champs actifs et c’est un sujet d’intérêt général pour la physique des fluides complexes. Leur rhéologie particulière les rend, en outre, intéressants pour des applications en ingénierie. La plus grande partie du travail regarde les solutions diluées de polymères. Deux aspects sont considérés : la statistique aux petites échelles, pour des élasticités modérées dans un régime de turbulence développée ; la déstabilisation d’un écoulement par non linéarités élastiques. L’effet des polymères sur les petites échelles turbulentes est étudié avec un modèle simplifié de fluide viscoélastique, en conditions d’isotropie et homogénéité. Les changements de la cascade turbulente sont considérés, et leurs conséquences pour la statistique à petite échelle sont examinées. Dans la limité opposée de non linéarités inertielles négligeables, les degrés de liberté polymériques peuvent déstabiliser un écoulement, quand l’élasticité de la solution est assez élevée. En augmentant l’élasticité on observe une transition vers des états « turbulents ». La phénoménologie expérimentale est reproduite numériquement et les propriétés statistiques sont caractérisées. Un autre sujet considéré est celui des mélanges binaires. On examine la séparation de phase entre deux fluides en présence d’un champ de vitesse forcé. On analyse la compétition entre les forces thermodynamiques et les cisaillements locaux, dans des mélanges actifs et passifs, et on souligne le rôle marginal du chaos Lagrangien pour le phénomène de l’arrêt de la mise en ordre<br>This thesis presents a theoretical and numerical study of turbulence in non-Newtonian fluids. The dynamics of these systems can be modelled in terms of transported active fields and constitutes a subject of general interest in complex fluid’s physics. Their peculiar rheological properties make them attractive also for engineering applications. The major part of the work concerns turbulence in dilute polymer solutions, i. E. Viscoelastic fluids. Two issues are considered : the small-scale statistics at moderate values of elasticity in a fully developed turbulence regime ; the destabilization of a laminar flow by means of purely elastic non linearities. The effect of polymers on small-scale turbulence has been studied in a simplified viscoelastic fluid model, in a homogeneous isotropic configuration. The modifications on the turbulent cascade have been addressed, as well as their consequences on small-scale statistics. In the opposite limit of negligible inertial non linearities, polymeric degrees of freedom can destabilize a flow, when the elasticity of the solution is large enough. At growing elasticity, a transition to chaotic, and turbulent, states is observed. The experimental phenomenology has been numerically reproduced and statistical properties have been characterized. Another item considered is that of binary mixtures. Phase separation between two fluids has been investigated in presence of an externally forced velocity field. The competition between thermodynamic forces and local shears has been examined in both active and passive mixtures and the marginal role of Lagrangian chaos in the phenomenon of coarsening arrest has been highlighted
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Mercer-Chalmers, June Dawn. "The thermodynamics of solutions and binary liquid mixtures." Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1005055.
Full textAbstract:
The thesis is presented in two parts. In part one, the excess thermodynamic properties have been determined for several binary liquid mixtures, with the aim of testing theories of liquid mixtures. The excess molar enthalpies, Hem, have been determined using an LKB flow microcalorimeter, and the excess molar volumes, Vem, have been determined using an Anton Paar densitometer. The HemS and VemS have been measured at 298.15 K for binary systems involving an alkanol (methanol, ethanol, I-propanol, 2-propanol) mixed with a hydrocarbon (l-hexene, I-heptene, l-octene, I-hexyne, I-heptyne, l-octyne, toluene, mesitylene, 0-, m-, or p-xylene, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane). The results show trends relating to the degree of unsaturation, or size, of component molecules as well as the position of the hydroxyl group on the alkanol. Measurements were also made on mixtures involving an (n-alkane + a pseudo-n-alkane) and ( a cYcloalkane + a pseudo-cycloalkane). Two theories of liquid mixtures were tested in this work. The first theory tested was the theory of Congruency. This theory was tested, by means of a null test, on a novel set of mixtures involving an n-alkane (hexane, heptane, octane, decane, dodecane) + a pseudo-nalkane,and mixtures of a cycloalkane (cyclopentane, cyclohexane, cycloheptane, cyclooctane)+ a pseudo-cycloalkane. Deviations from the theory was less than the experimental error for the (n-alkane + pseudo-n-alkane) mixtures. However, significant deviations were observed for the mixtures of (a cycloalkane + a pseudo-cycloalkane). The second theory tested was the Flory theory, which has been used to predict the excess molar enthalpies and excess molar volumes for the mixtures involving (a 1-alkene, or 1-alkyne, or methyl-substituted benzene) + an alkanol. The results show that the theory does not hold for hydrocarbon mixtures involving an alkanol. In the second part of this thesis, the partial molar volumes, at infinite dilution, of binary solution involving a solid solute (18-crown-6 ether, dibenzo-18-crown-6 ether, dicyclohexanov 18-crown-6 ether, 15-crown-5 ether, or cryptand-222) are determined in various solvents. The results were repeated with a view to determine the volume changes at infinite dilution upon complexation, ΔV∞ of the crown ether or cryptand with a metal halide salt, MX (NaCl, NaI, KCl, KI, CsCl, CsI). The ΔV∞ results were compared with results in the literature for cryptand-222 (c-222) and dibenzo-18-crown-6 ether (B₂CE6) complexed with MX, and the study was extended to include further MX complexes with c-222 and B₂CE6, as well as MX complexes with 15-crown-5 ether and dicyclohexano-18-crown-6 ether. ΔV∞ results were correlated with the Hepler prediction of the electrostriction solvent effect.
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Thongchai, Prem. "An investigation into the thin film deposition of binary oxide, ternary oxide and binary sulphide materials." Thesis, University of Bath, 2019. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767603.
Full textAbstract:
Metal oxide and metal sulphide materials dominate a wide range of attractive properties and also to provide potential performances to various applications. There is a challenge to prepare these materials as a thin film with great quality and properties. Aerosol-assisted chemical vapour deposition (AACVD) is a promising technique to offer a desired thin film. The objective of this work is the preparation of the metal oxide and metal sulphide thin films via AACVD technique with single source precursor. The properties of deposited films were characterised.
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Vidal, Vazquez Migvia del C. "Binary mixture flammability characteristics for hazard assessment." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2536.
Full textAbstract:
Flammability is an important factor of safe practices for handling and storage of
liquid mixtures and for the evaluation of the precise level of risk. Flash point is a major
property used to determine the fire and explosion hazards of a liquid, and it is defined as
the minimum temperature at which the vapor present over the liquid at equilibrium
forms a flammable mixture when mixed with air.
Experimental tests for the complete composition range of a mixture are time
consuming, whereas a mixture flash point can be estimated using a computational
method and available information. The information needed for mixture flash point
predictions are flashpoints, vapor pressures, and activity coefficients as functions of
temperature for each mixture component. Generally, sufficient experimental data are
unavailable and other ways of determining the basic information are needed. A
procedure to evaluate the flash point of binary mixtures is proposed, which provides
techniques that can be used to estimate a parameter that is needed for binary mixture
flash point evaluations.
Minimum flash point behavior (MFPB) is exhibited when the flash point of the
mixture is below the flash points of the individual components of the mixture. The
identification of this behavior is critical, because a hazardous situation results from
taking the lowest component flash point value as the mixture flash point.
Flash point predictions were performed for 14 binary mixtures using various Gex
models for the activity coefficients. Quantum chemical calculations and UNIFAC, a
theoretical model that does not require experimental binary interaction parameters, are employed in the mixture flash point predictions, which are validated with experimental
data. MFPB is successfully predicted using the UNIFAC model when there are
insufficient vapor liquid data.
The identification of inherent safety principles that can be applied to the
flammability of binary liquid mixtures is also studied. The effect on the flash point
values of three binary mixtures in which octane is the solute is investigated to apply the
inherent safety concept.
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Fall, Jaimie Linn. "Multiphase equilibria in binary and ternary hydrocarbon systems containing carbon dioxide /." Access abstract and link to full text, 1985. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8603795.
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Chong, Kin-Hoe. "Biosorption of cadmium, copper and zinc in binary and ternary systems." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22647.
Full textAbstract:
A biosorbent prepared from Ascophyllum nodosum seaweed biomass, designated as FCAN2, was examined for its sorption capacity. Equilibrium batch sorption studies were performed using two-metal systems respectively comprised of (Cd + Cu), (Cd + Zn), (Cu + Zn) and a three-metal system comprised of (Cd + Cu + Zn). In the evaluation of the two-metal sorption system performance, simple sorption isotherm curves had to be replaced by three-dimensional sorption isotherm surfaces. In order to describe the isotherm surfaces mathematically, three Langmuir-type models were evaluated. The apparent one-parameter Langmuir constant was used to quantify FCAN2 'affinity' for one metal in the presence of another one. In order to represent the equilibrium data of the ternary system, a multicomponent Langmuir model was adopted and triangular equilibrium diagrams were used. Mathematical models for the two- and three-metal sorption systems enabled quantitative estimation of one metal sorption inhibition due to the influence of the other metal(s). For biosorption on FCAN2 at pH 4.5, the inhibition dominance observed in the two- and three-metal systems was Cu $>$ Cd $>$ Zn.