This dissertation develops computational techniques to aid in efficiently studying petrologic systems that would otherwise be challenging. It then focuses on a case study in which the transition from diagenesis to syn-magmatic heating led to a recrystallization and sulfur mobilization. A Markov-chain Montecarlo-based methodology is developed to allow for the assessment of uncertainty in calculated phase assemblage diagrams. Such phase equilibria are ubiquitous in modern petrology, but uncertainties are rarely considered. Methods are discussed for visualizing and quantifying emergent patterns as phase diagrams are re-calculated with input data modified within permitted uncertainty bounds, and these are implemented in a new code. Results show that uncertainty varies significantly across pressure-temperature space and that in some conditions, estimates of stable mineral assemblage are known with very little confidence. A Machine-Learning (ML) based methodology is developed for automatically identifying unknown phases using Electron-dispersion spectra (EDS) in concert with a Random Forest Classification algorithm. This methodology allows for phase identification that it is insensitive to overfitting and noisy spectra. However, this tool is limited by the amount of reference spectra available in the dataset on which the ML algorithm is trained. The approximately 250 EDS spectra in the current training database must be supplemented to make the tool more widely useful, though it currently has an excellent success rate for correctly identifying various sulfide and oxide minerals. An analysis of paragenesis associated with Central Atlantic Magmatic Province (CAMP) intrusions helps to better constrain the dynamics of magma emplacement, while also providing a method for estimating the amount of sedimentary sulfide-sequestered sulfur mobilized as a result of magnetite formation associated with igneous activity. This method demonstrates that dike emplacement can trigger liberation of sedimentary sulfur with no direct cooling impact on climate. / Doctor of Philosophy / Determining how rocks and minerals form is fundamental to the geosciences. Here I present two computer-based techniques that can help address this essential problem. One method involves carefully determining uncertainty in thermodynamic modeling. Knowing the amount of uncertainty ultimately allows us to know the degree of confidence we can have in our model-based conclusions. The second computer-based technique involves using Machine Learning to automate the identification of minerals using an Electron-dispersion spectra (EDS) measured using a Scanning Electron Microscope (SEM). In theory, computers are much better than humans at quickly and repeatedly processing large sets of data such as EDS. This technique works well when the computer is successfully 'trained' on a large set of data but is somewhat limited in this case because there isn't diverse enough data available to train the computer. We therefore need better training data so that we can more fully benefit from this mineral identification tool. A third project I worked on involved assessing the impact of magma intruding into sedimentary rocks of the Culpeper Basin in northern Virginia. This occurred roughly 200 million years ago during the rifting of Pangea. The sedimentary rock around the magma heated up so much that water in the rock boiled and caused the rock to become fractured. After this a hydrothermal system was established that helped convert pyrite to magnetite, removing sulfur from the rocks in the process.

Yes / The thermodynamic stability of caffeine (CA) cocrystals with dicarboxylic acids (DAs) as coformers was investigated in the presence of a range of structurally related dicarboxylic acids (SRDs). Two experimental conditions (slurry and dry-grinding) were studied for mixing the cocrystal and the SRD additive. The additives oxalic, malonic and glutaric acid led to the replacement of the acid coformer for certain cocrystals. Interestingly, a change in stoichiometry was observed for the CA:maleic acid system. A stability order among the cocrystals was established depending on their tendency to replace the coformer. To understand the factors controlling the relative stabilities, lattice energies were calculated using dispersion corrected Density Functional Theory (DFT). Gibbs free energy changes were calculated from experimental solubilities. The observed stability order corroborated well with lattice energy and Gibbs free energy computations.

Intracellular membraneless organelles commonly arise by phase separation of biomolecules and are essential for cellular processes such as signaling, gene regulation, and reproduction. The abnormal behavior of these biomolecular condensates can lead to cancer and neurodegenerative diseases. Equilibrium thermodynamics can explain condensate properties like internal composition, selective segregation of molecules, and conditions for their assembly. However, cells are inherently out of equilibrium, and hence, many of the functionalities of intracellular condensates arise from coupling phase separation to active processes such as post-translational modifications. The mechanisms that cells employ to regulate the properties and associated functions of these out-of-equilibrium condensates are poorly understood. In vitro condensate models provide a bottom-up approach to gaining insights into these underlying active mechanisms that may be difficult to isolate in vivo. Complex coacervates formed by liquid-liquid phase separation of oppositely charged polyelectrolytes have been effectively used to emulate condensate properties because of their compatibility with biological processes and their responsiveness to environmental cues. In this dissertation, we aim to use in vitro coacervate systems to reproduce two main characteristics of native condensates - size regulation and stimuli-responsive internal structure. The two in vitro models described in this thesis utilize the effect of pH on coacervation to demonstrate control over coacervate size or morphology under non-equilibrium conditions. The experimental system consists of an anionic enzyme phase separating with a weak polycation, DEAE-dextran, to form micron-sized coacervate drops. The charges of both the polyelectrolytes are pH sensitive, which makes the electrostatic dominated coacervate assembly pH responsive. The anionic enzyme enriched in the coacervate catalyzes a reaction that changes the solution pH. In Chapter 2, we demonstrate that the anionic catalase enzyme causes a pH increase that dissolves the coacervates. In turn, the diffusion-limited consumption of substrate within large coacervate drops slows the enzymatic reaction, thereby completing the negative feedback loop. Using a combination of modeling and experiments, we show that drops larger than a critical size can potentially support a localized pH increase that leads to a size-dependent dissolution of coacervates. Although the presence of oxygen bubbles prevents the realization of size control in this system, our work provides a framework to achieve size regulation in active coacervates exhibiting negative feedback between coacervate assembly and enzymatic reactions. In Chapter 3, we harness the pH-sensitivity of coacervates to elucidate the mechanism of vacuole formation within glucose oxidase/DEAE-dextran coacervates in response to an external pH decrease. We show that the formation of hollow structures or vacuoles within the coacervates depends on the rate of pH decrease and droplet size. Our results reveal that vacuole development occurs under non-equilibrium conditions due to the diffusion-limited mobility of the polycation during a rapid pH decrease. This work serves as a platform to regulate condensate structure in response to changes in the local environment, laying the groundwork for designing synthetic cells with new capabilities.

Yes / The removal of the ubiquitous phenol and phenolic compounds in industrial wastes is a critical environmental issue due to their harmful threats to wildlife and potential adverse human health effects. The removal of such compounds is therefore of significant importance in water treatment and reuse. In recent years, reverse osmosis (RO) has been successfully utilised in several industrial processes and wastewater treatment including phenol removal. In this paper, a new model based on a spiral-wound RO process is developed for the removal of phenol from wastewater. A simplified mathematical algorithm using an irreversible thermodynamic approach is developed. This results in a set of non-linear Differential and Algebraic Equations (DAEs), which are solved based on a number of optimised model parameters using a combined methodology of parameter estimation and experimental phenol-water data derived from the literature. The effects of several operational parameters on the performance (in terms of removal of phenol) of the process are explored using the model.

Alumino-silicate systems are of great interest for materials scientists and geochemists. Thermodynamic knowledge of these systems is useful in steel and ceramic industries, and for understanding geochemical processes. A popular and efficient approach used to obtain a self-consistent thermodynamic dataset is called CALPHAD. It couples phase diagram information and thermochemical data with the assistance of computer models. The CALPHAD approach is applied in this thesis to the thermodynamic modelling and assessments of the CaO-Al2O3-SiO2, MgO-Al2O3-SiO2 and Y2O3-Al2O3-SiO2 systems and their subsystems. The compound energy formalism is used for all the solution phases including mullite, YAM, spinel and halite. In particular, the ionic two sub-lattice model is applied to the liquid solution phase. Based both on recent experimental investigations and theoretical studies, a new species, AlO2-1, is introduced to model liquid Al2O3. Thus, the liquid model corresponding for a ternary Al2O3-SiO2-M2Om system has the formula (Al+3,M+m)P (AlO2-1,O-2, SiO4-4,SiO20)Q, where M+m stands for Ca+2, Mg+2 or Y+3. This model overcomes the long-existing difficulty of suppressing the liquid miscibility gap in the ternary systems originating from the Al2O3-free side during the assessments. All the available and updated experimental information in these systems are critically evaluated and finally a self-consistent thermodynamic dataset is achieved. The database can be used along with software for Gibbs energy minimization to calculate any type of phase diagram and all thermodynamic properties. Various phase diagrams, isothermal and isoplethal sections, and thermochemical properties are presented and compared with the experimental data. Model calculated site fractions of species are also discussed. All optimization processes and calculations are performed using the Thermo-Calc software package. / QC 20100607

There are two parts in this study. The first part is to test the validity of the assumption of thermodynamic equilibrium between fine particulate (PM2.5) nitrate and ammonium and gas-phase nitric acid (HNO3(g)) and ammonia (NH3(g)). A rough estimation of the characteristic time to achieve thermodynamic equilibrium is first carried out, which suggests that PM2.5 and gas-phase species are in thermodynamic equilibrium. Then equilibrium is tested by calculating the equilibrium concentrations of HNO3(g) and NH3(g) implied by the PM2.5 inorganic composition, temperature and relative humidity observed at the Atlanta Supersite 1999 using ISORROPIA model. The second part of this study is to analyze the ground-level ozone pollution precursor relationships in Hong Kong area. Characteristics of O3 precursors are explored. Trace gases NO and CO, VOCs, absorption coefficient, temperature and solar radiation are associated with the O3 formation. Specific VOC and VOC-sources that contribute most to the formation of photochemical smog are identified. The accuracy of pollutant emission inventories for Hong Kong and PRD region is also assessed. Combined with back trajectory information, dCO/dNOy is used to define whether O3 is locally or regionally occurred. An OBM is used to investigate the relative benefits of various emission-control strategies. Generally the formation of O3 throughout much of Hong Kong area is limited by VOC, in which reactive aromatics are dominant.

L'objectif de ce travail est l'étude de la solubilité d'un principe actif hydrophobe modèle, le diazépam, dans un solvant binaire d'intérêt pour la lyophilisation industrielle, le mélange eau + tert-butanol. Un modèle décrivant la dépendance du volume d'excès du solvant vis-à-vis de sa composition et de sa température a été validé à partir de données mesurées au cours de ce travail et de données de la littérature. Les variations de diverses propriétés partielles d'excès issues de ce modèle en fonction de la composition du solvant et de sa température ont été interprétées en termes d'interactions moléculaires et d'arrangements structuraux. Ensuite, la solubilité du diazépam dans le solvant a été mesurée en fonction de sa composition et de sa température. La masse volumique des phases liquides saturées ainsi que les propriétés thermophysiques des cristaux de principe actif originels et des phases solides en excès issues des équilibres solide-liquide ont été déterminées. Les propriétés thermodynamiques caractéristiques du processus de dissolution du diazépam en condition d'équilibre ont été obtenues à partir de la dépendance de sa solubilité vis-à-vis de la température. À partir de ces données, les propriétés thermodynamiques d'excès du diazépam dans les différents mélanges saturés ont été calculées et les forces responsables de la variation de la solubilité du principe actif avec la composition du solvant ont été identifiées. Enfin, la capacité de deux modèles d'enthalpie libre d'excès, le modèle de Scatchard-Hildebrand combiné ou non au modèle de Flory-Huggins, à corréler les données expérimentales de solubilité a été évaluée et comparée / The aim of this work is to investigate the solubility behavior of a hydrophobic model drug, diazepam, in a binary solvent of industrial interest for freeze-drying, the water + tert-butyl alcohol mixture. Firstly, a model describing the dependence of the excess volume of the solvent on both composition and temperature was validated from experimental data obtained during this work and literature data. This model was used to derive expressions for excess partial thermodynamic quantities and their variations with respect to composition and temperature were discussed in terms of molecular interactions and structural arrangements in solution. Secondly, the solubility of diazepam in neat solvents and different binary solvent mixtures was determined. The density of drug-saturated mixtures was also determined as well as the thermophysical properties of original diazepam crystals and excess solid phases from solid-liquid equilibria. The thermodynamic properties relative to the dissolution process of the drug under saturation condition were obtained from solubility temperature dependence using van’t Hoff plots. From these, the excess partial thermodynamic properties of diazepam in saturated mixtures were computed and the forces driving the drug solubility variation with respect to the solvent composition were identified. Finally, two excess Gibbs energy models, the Scatchard-Hildebrand and combined Scatchard-Hildebrand/Flory-Huggins models were tested to represent the solubility data. Their capabilities in correlating the dependence of the drug solubility on both the solvent composition and temperature were evaluated and compared

The scope of this thesis is the Miller engine cycle analysis and its practical application on a turbocharged spark ignited engine. Based on the sensitivity analysis of the limits affecting the ideal Miller cycle thermal efficiency a thermodynamic model of the engine with a prolonged expansion was set up in the GT-POWER software. The results of the analyses were used to evaluate the feasibility of the reference engine conversion for an operation with Miller cycle.

The diploma thesis deals with the issue of replacement of non-ecological refrigerant R22 according to the requirements of relevant juristic regulations and of subsequent influence of this replacement to the efficiency of air conditioning systems. The theoretical part is focused on proceeding processes in thermodynamic cycles and during heat transfer, then determines calculation of cooling and heating factor in context with experimental measurement. The experimental measurement utilizes to the assessment of operation of heat pump after refrigerant replacement and it is source for the composion of economical evaluation of alternative solutions due to the particular choice of refrigerant replacement.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Thermodynamic models have been investigated extensively since Johannes van der Waals first devised a mathematical relation capable of predicting both vapour and liquid phases for a mixture at equilibrium. With the advent of modern computing power, these equations of state have gone from their humble empirical beginnings to the comprehensive and fundamentally derived models we have today. One such physically sound model is the Statistical Associating Fluid Theory (SAFT) family of equations, derived from the molecular perturbation theories of the 1980’s. The relative youth of this thermodynamic framework has meant that much work has gone into modification and optimisation of the model recently. The variants of particular interest to this work are the simplified perturbed chain SAFT equations with the Jog & Chapman (sPC-SAFTJC) and Gross & Vrabec (sPC-SAFTGV) polar terms. Each of the polar terms supports one adjustable polar parameter that relates to the quantity of polar segments in the reference fluid but not necessarily its position in the carbon chain. The strength of polar interactions is known to decrease as the functional group moves away from the terminal methyl group and the effects of steric hindrance increase. Thus, in question here is whether the models can account for the change in polar interactions associated with the changing position of the polar group, by only adjusting the values of the existing pure component parameters; that is, in lieu of a position specific parameter. The carbonyl group in ketone molecules is one such polar group, and it is this homologous series that is the focus of this study. The decrease in polar interactions as the carbonyl group in a ketone molecule shifts centrally is apparent from the lower boiling points of the isomers where the polar group is central as compared to those where the functional group is nearer the terminal methyl group. The effect of this functional group shift on binary phase behaviour has not previously been assessed for any system however, as the lack of experimental data attests. Thus, experiments had to be conducted to generate phase equilibrium data for systems comprising each structural isomer of a mid-length ketone with a common second component with no functionality. This limitation was imposed to isolate the cause of experimentally observed phenomena to the shifting polar group alone. The generated data could then be appropriately modelled using the polar sPC-SAFT variants and the capabilities of each model, as outlined above, assessed. To this end, isobaric binary vapour-liquid equilibrium data were measured for 2-, 3- & 4-heptanone with three separate normal alkanes of similar length (n-octane, n-nonane & n-decane) at 40kPa. The apparatus used was a dynamic Gillespie VLE still with temperature and pressure accuracies of 0.03°C and 1.6mbar respectively. Equipment verification was achieved through the reproduction of experimental data for the ethanol/1-butanol system at 1.013bar. The vapour and liquid samples for all nine systems were analysed by gas chromatography with a maximum compositional error of ±0.022 mole fraction. All reported data were found to be thermodynamically consistent using both the L/W and McDermott-Ellis consistency tests. When paired with a common n-alkane, all three structural heptanone isomers displayed similar qualitative trends in phase behaviour. Minimum boiling azeotropes were measured in all nine systems; in the high alkane region for n-octane systems (~98 mole%), the equal concentration region for n-nonane systems (34 mole% to 53 mole%) and in the very dilute n-alkane region for n-decane systems (~3 mole%). The n-nonane systems in particular highlighted the effect of shifting functional group, with completely separate phase envelopes away from the pure alkane composition space evident in a particularly small temperature range. Modelling was performed using in-house developed software, with pure component parameters generated for each system using five different regression procedures. The first was traditional fitting of the segment diameter (σ), segment number (m), segment energy (є/k) and the respective polar parameter (xp, np) to DIPPR correlations of pure component saturated vapour pressure, liquid density and the heat of vaporisation. The latter four procedures included the fixing of the polar parameter according to functional group correlations and the three instances of including the binary VLE data set for each of the three alkanes considered in this work. When applied to the nine binary ketone-alkane systems measured in this work, excellent predictions of the experimental data were in evidence in most cases and only small binary interaction parameters were necessary to correlate the data where pure predictions were poor. The performance of the parameter sets based on the fixing of the polar parameter and the inclusion of VLE data were consistent and of a high quality for both models, with near identical parameters generated in all four cases for each of the nine systems. The parameter sets generated in this fashion were shown to be applicable not only to the systems measured in this work, but also successfully predicted the independently measured experimental data of the n-hexane/4-heptanone system. It was thus concluded that either of these regression alternatives are viable for the generation of accurate component parameters, and the choice of VLE data set included is trivial. The pure predictions of the sPC-SAFTGV model were generally better than its sPC-SAFTJC counterpart, particularly in the case of the traditionally regressed parameter sets. sPC-SAFTGV displayed constant qualitative agreement with the experimental data for each of the heptanone isomers with a given n-alkane. The quality of the predictions of sPC-SAFTJC, however, worsened significantly as the polar interactions diminished from 2- to 4-heptanone, with no predictions even possible for the least polar isomer. This was attributed to the different perturbation theories used in the development of these terms, but a more detailed study would be necessary to confirm this. This work thus shows an apparent inability of the sPC-SAFTJC equation of state to account for the decreasing polar interactions associated with the carbonyl group in a ketone molecule shifting centrally, while sPC-SAFTGV produces qualitatively good fits for all three isomers. These flaws can be overcome through the incorporation of VLE data in the regression procedure if such data is available, or otherwise through the use of group specific correlations for fixing the polar parameter value. / AFRIKAANSE OPSOMMING: Sedert Johannes van der Waals die eerste wiskundige verhouding ontwikkel het wat beide die damp- en vloeibare fases van 'n mengsel by ewewig kon voorspel, is die veld van termodinamiese modellering al deeglik ondersoek. Na die koms van die moderne rekenaars het hierdie vergelykings van hul nederige empiriese wortels gegroei tot die omvattende, fundamentele modelle wat ons vandag het. Een so 'n fundamenteel gebaseerde familie van vergelykings is die ‘Statistical Associating Fluid Theory’ (SAFT) modelle, wat afgelei is vanaf molekulêre versteuringsteorieë, ontwikkel in die 1980s. Hierdie relatiewe jong modelle het in die afgelope ruk aansienlike aanpassing en optimering ondervind. Modelvariante van besondere belang tot hierdie werk, is die vereenvoudigde versteurde ketting of ‘simplified perturbed chain’ SAFT vergelykings, met Jog & Chapman (sPC- SAFTJC) en Gross & Vrabec (sPC- SAFTGV) polêre terme. In die sPC-SAFT toestandsvergelyking word elkeen van die polêre terme ondersteun deur een polêre veranderlike. Hierdie veranderlike is afhanklik van die aantal polêre segmente in die verwysingsvloeistof, maar nie noodwendig hul posisie in die koolstofketting nie. Daarteen is dit bekend dat die polêre interaksies tussen molekules swakker word soos die polêre groep wegbeweeg van die terminale metielgroep, en steriese hindernis ʼn groter rol begin speel. Dus is die vraag of die model die verandering in die polêre interaksie, as gevolg van veranderende posisie van die polêre groep, kan voorspel deur in plek van ʼn posisie afhanklike parameter, slegs ʼn aanpassing van die polêre waardes van die suiwer komponente te maak. Die karbonielgroep in ketoon molekules is een so 'n polêre groep, en ʼn homoloë reeks ketone word in hierdie studie ondersoek. Die afname in die polêre interaksie soos wat die karbonielgroep in 'n ketoon molekule weg skuif vanaf die terminale metiel groep is sigbaar deur die afname in kookpunt van die verskillende isomere. Hierdie effek van die funksionele groepsposisie op binêre fasegedrag is nog nie voorheen vir enige stelsels geëvalueer nie en geen eksperimentele data is vrylik beskikbaar nie. Om hierdie tekortkoming in die literatuur aan te spreek, is eksperimentele fase ewewig data gemeet. ʼn Reeks stelsels is ondersoek wat elk bestaan uit ʼn struktuurisomeer van ʼn mid-lengte ketoon en ʼn tweede komponent met geen funksionele bydrae. Eksperimente is so opgestel om die effek van die skuiwende polêre groep op die fasegedrag te isoleer en kwalitatief te ondersoek. Die gegenereerde data is dan gemodelleer met behulp van die polêre sPC- SAFT variante, soos hierbo gespesifiseer, en die vermoëns van elke model is beoordeel. Isobariese binêre fase ewewig data is by 40kPa gemeet vir damp-vloeistof stelsels bestaande uit 2, 3 & 4 heptanoon, gemeng met drie verskillende normaal alkane van vergelykbare kettinglengte (n-oktaan, n-nonaan & n-dekaan). Die apparaat wat gebruik was is 'n dinamiese Gillespie VLE eenheid met temperatuur- en drukakkuraatheid van 0,03°C en 1.6mbar, onderskeidelik. Die akkuraatheid van die toerusting is bevestig deur eksperimentele data vir ʼn etanol/1-butanol stelsel by 1.013bar te reproduseer. Die damp en vloeibare monsters vir al nege stelsels is ontleed deur gaschromatografie met 'n maksimum komposisionele fout van ± 0,022 (molfraksie). Alle data is as termodinamies konsekwent gevind deur van beide die L/W en McDermott-Ellis konsekwentheidstoetse gebruik te maak. Mengsels van die drie strukturele isomere van heptanoon met ʼn gemene n-alkaan het tydens eksperimente soortgelyke kwalitatiewe tendense in fasegedrag getoon. Gedurende eksperimente is die lae kookpunt asiotrope gemeet vir al nege stelsels. Die asiotrope verskyn in die hoë alkaan konsentrasies (~98 mol%) vir n-oktaan stelsels, medium konsentrasies (34 mol% tot 53 mol%) vir n-nonaan stelsels en baie verdunde konsentrasies (~ 3 mol%) vir n-dekaan stelsels. Die n-nonaan stelsels beeld veral die effek van die verskuiwing van die funksionele groep uit, met diskrete fasegrense wat duidelik apart staan van die suiwer alkaan ruimte, binne ʼn klein temperatuurverskil. Modellering van die stelsels is uitgevoer met behulp van sagteware wat in-huis ontwikkel is. Suiwer komponent data is gegenereer vir elke stelsel deur van vyf verskillende regressie prosedures gebruik te maak. Die eerste is die tradisionele passing van die segment deursnee (σ), segment nommer (m), segment energie (є/k) en die onderskeie polêre parameters (xp, np) op DIPPR korrelasies van die suiwer komponent versadigde dampdruk, vloeistof digtheid en die hitte van verdamping. Die oorblywende vier prosedures sluit in die bepaling van die polêre parameter deur funksionelegroep korrelasies, en drie gevalle waar die binêre VLE data vir elk van die drie alkane ingesluit is. Deur hierdie prosedures op die modellering van die nege binêre ketoon/alkaan stelsels toe te pas, is uitstekende passings van die eksperimentele data verkry met slegs baie klein binêre interaksie parameters nodig waar voorspellings minder akkuraat was. Die prestasie van die parameter stelle, gebaseer op die bepaling van die polêre parameter en die insluiting van VLE data, is konsekwent en van 'n hoë gehalte vir albei modelle, met 'n byna identiese parameters gegenereer in al vier gevalle vir elk van die nege stelsels. Die parameter stelle wat op hierdie metode gegenereer is, is nie net toepaslik gevind op eksperimentele data gemeet in hierdie werk nie, maar ook op onafhanklike data vir die n-heksaan/4-heptanoon stelsel. Daar is tot die gevolgtrekking gekom dat beide van die regressie alternatiewe lewensvatbaar is vir die generasie van akkurate suiwer komponent parameters, en dat die insluiting van die VLE data triviaal is. Die suiwer sPC - SAFTGV voorspelling was oor die algemeen beter as die suiwer sPC- SAFTJC model met die voorspelling van data, veral in die geval van passings gedoen met parameters verkry vanaf tradisionele regressie metodes. sPC- SAFTGV het ʼn voortdurende, kwalitatiewe ooreenkoms met eksperimentele data getoon vir elk van die nege stelsels. Daarteen het voorspellings deur sPC- SAFTJC beduidend verswak soos die polêre interaksies afgeneem het vanaf 2- na 4- heptanoon, met geen akkurate voorspelling moontlik vir die minste polêre isomeer nie. Die verskynsel kan toegeskryf word aan die verskil in versteuringsteorieë wat gebruik word in die ontwikkeling van die onderskeie toestandsvergelykings, maar ʼn meer in-diepte ondersoek is nodig om hierdie teorie te bevestig. Hierdie werk toon dus 'n skynbare onvermoë van die sPC - SAFTJC toestandsvergelyking om die verandering in polêre interaksie, as gevolg van die veranderende posisie van die polêre groep, vir die karbonielgroep in ʼn ketoon te voorspel, terwyl die sPC-SAFTGV toestandsvergelyking goeie kwalitatiewe passings vir al drie isomere bied. Hierdie tekortkominge kan oorkom word deur VLE data, indien beskikbaar, in die regressie prosedure in te sluit, of deur die gebruik van groep spesifieke korrelasies vir die aanpassing van die polêre parameter.