The investigation described in this thesis is aimed at determining the effect of heated air flow on the behaviour of capillary barriers. In order to achieve the objectives of this investigation, a number of tasks were undertaken, as described hereinafter. First, a laboratory scale testing was carried out to determine the effect of heated air flow on the volumetric water content (VWC) and matric suction in a layer of soil representing the coarse grained soil layer of a capillary barrier. Several types of instruments were used to measure the VWC, matric suction, and temperature at different locations within the soil. Next, a numerical analysis was undertaken to simulate the behaviour of the soil mass subjected to thermal changes in the laboratory experiments. Lastly, two case studies were analyzed with and without the heated air flow in the coarse grained soil layer to validate the proposed model. The method used in this investigation was based on: (1) application of temperature change at the perimeters of the pipes installed in the coarse grained soil layer near the interface between the fine grained and coarse grained soil layers; and, (2) application of suction as a boundary condition at the perforated parts of the pipes to decrease VWC and increase matric suction in the soil mass. Using this specific method, the results of the finite element analyses of the laboratory experiments and the two case studies demonstrated that the heated air flow through the coarse grained soil layer of a capillary barrier would improve its performance as a soil cover for a number of engineering applications. Comparisons of measured and calculated values of VWC and matric suction showed good agreement providing further proof of the validity of the method.

This work deals with properties and physical phenomena occurring in semiconductor materials. In details are described generation - recombination processes in a state of thermodynamic disequilibrium. The output of work is a software application simulating waveforms of energy levels in the band's own models and impurity semiconductors, depending on the type of semiconductor, impurities concentration and temperature. Finally, the processed virtual lab experiment deliverable in the educational process.

The master´s thesis concentrates on a project of condensing steam turbine for existing heating plant with back pressure turbine. The master´s thesis subject consists in the thermodynamic calculation of regulating stage and turbine stages. Design documentation is worked up according to the calculated record. From calculated power of turbine is worked a basic project of gearbox and disposal arrangement system.

It is a theorem of Denker and Urbański that if T:ℂ→ℂ is a rational map of degree at least two and if ϕ:ℂ→ℝ is Hölder continuous and satisfies the “thermodynamic expanding” condition P(T,ϕ) > sup(ϕ), then there exists exactly one equilibrium state μ for T and ϕ, and furthermore (ℂ,T,μ) is metrically exact. We extend these results to the case of a holomorphic random dynamical system on ℂ, using the concepts of relative pressure and relative entropy of such a system, and the variational principle of Bogenschütz. Specifically, if (T,Ω,P,θ) is a holomorphic random dynamical system on ℂ and ϕ:Ω→ ℋα(ℂ) is a Hölder continuous random potential function satisfying one of several sets of technical but reasonable hypotheses, then there exists a unique equilibrium state of (X,P,ϕ) over (Ω,Ρ,θ).

<p>Capillary electrophoresis is a high resolution microseparation technique that is increasingly being recognized as a physical tool to characterize biomolecular interactions, where dynamic complexation of analytes with discrete additives is used to resolve complex mixtures of solutes, including enantiomers. Despite the wide interest in developing high-throughput screening platforms for drug discovery or disease prognosis, little emphasis has been placed on enhancing "pre-analysis steps" that are often the most crucial component determining the overall performance of a method. Off-line sample pretreatment protocols for complex biological samples are often time-consuming and not amenable for automation. The major goal of this thesis is the development of a single-step analytical platform by CE for targeted metabolites that integrate several different sample pretreatment processes during separation, which can also be used to characterize the thermodynamic parameters associated with covalent and non-covalent interactions. Two distinct projects in this thesis have been examined involving boronic acid-polyol and protein-cyclic nucleotide interactions that illustrate the concept of integrating sample pretreatment with chemical analysis based on dynamic complexation-capillary electrophoresis.</p> <p>The first project consists of a new strategy for enhancing target selectivity when using 3-nitrophenylboronic acid as an electrokinetic probe in dynamic complexation-capillary electrophoresis. The differential migration of ternary boronate ester complexes permits the selective analysis of micromolar levels of UV-transparent polyol stereoisomers in urine samples that is applicable to single-step screening of in-born errors of sugar metabolism, such as galactosemia. In the second project, the impact of ligand binding on protein stability is assessed by dynamic ligand exchangeaffinity capillary electrophoresis with laser-induced native fluorescence detection. This is a convenient yet rapid format for comparative thermodynamic studies of a regulatory subunit of protein kinase involving different cyclic nucleotide analogues without off-line sample pretreatment, since ligand exchange and protein unfolding processes are integrated incapillary during electromigration.</p> / Thesis / Master of Science (MSc)

<p> The partitioning of niobium to slag and gaseous niobium oxide vapourizing from metal/slag may cause niobium losses and erratic recovery rates in steelmaking practices. Knowledge of the volatility and activities of niobium oxides in slag melts are of great value for both theoretical evaluation and practical applications in niobium microalloyed steels. Because of the multi-valence state of niobium ions in slags, the behaviour of niobium in metallurgical slags is complicated. So far, little systematic attempts have been made and activity data of niobium oxides in slags are extremely scarce. The aim of this study is to determine precise data on the vapour pressures of niobium oxides, and consequently, to obtain information on thermodynamic quantities of niobium oxides in slag melts.</p> <p> The thermodynamic properties of niobium oxide in CaO-SiO2-NbOx and CaOSiO2-Al2O3-NbOx slag melts were determined by employing the transpiration method from 1800-1873K under a controlled atmosphere. To confirm the validity of the transpiration method for the measurement of thermodynamic properties, the binary alloy system silver-gold was chosen for a comparison with the same property which has been measured by other recognized procedures. The agreement with literature results confirmed that the measurement yields reliable results for thermodynamic activity data by the transpiration method.</p> <p> The vapourization of liquid Nb2O5 was studied as a function of partial pressure of oxygen in the system and this confirms that atmosphere control is the essential condition for the vapourization study. The gaseous niobium oxide species was verified to be NbO2; hence, Nb2O5 vapourizes by the reaction Nb2O5(1) = 2NbO2(g)+1/2O2(g). Heat of vapourization was estimated by applying the second law method and comparison with the literature showed a fairly good agreement.</p> <p> The thermodynamic properties of niobium oxide in the slag system of CaO-SiO2-NbOx and CaO-SiO2-Al2O3-NbOx were measured by varying the experimental conditions of slag basicities, slag compositions, temperature and oxygen partial pressures. From the basicity dependency of the activity coefficient for each oxide in this study, it is proposed that niobium oxide behaves as an amphoteric oxide and niobium pentoxide as an acidic oxide. On the other hand, it was observed in the redox equilibrium experiment that NbO2.5 becomes predominant as the slag basicity increases. However, insufficient interaction parameters as well as parameter conversions prevent the application of the regular solution model. The co-relationship between the ionic diameter and ionic energy was discovered and shows good agreement with calcium oxide and silicon oxide. With the interaction parameter and converting parameter attained, the regular solution model shows good agreement for the activity coefficients between measurement and calculation.</p> / Thesis / Doctor of Philosophy (PhD)

No description available.

Yes / This investigation reports the first study to predict natural gas hydrate formation using both Aspen HYSYS® and HydraFlash software for various gas compositions and thermodynamic inhibitors (monoethylene glycol [MEG] concentrations at 10, 20, 30, and 40 wt.% and methanol concentrations at 10 and 20 wt.%). The simulated predictions are compared with the results of the experimental data in the literature. It has been shown that HydraFlash software can accurately predict hydrate formation conditions for a given industrial case, without having to carry out costly experimental work. This work also evaluated the effect of inhibitors and it appears that inhibitor type and concentration are determined according to condition of gas composition. MEG is consequently selected as the most ideal hydrate inhibitor for the industrial case. This also was confirmed through COSMO-RS studies in which the sigma profile and sigma potential of the considered inhibitors were obtained and presented using density functional (DFT) calculations to verify the hydrogen bonding affinities of the inhibitors to water molecules. HydraFlash was utilized to predict the dissociation conditions of hydrates under the influence of a high concentration of MEG inhibition, reaching up to 40 wt.% at 313 K and a pressure of 311.1 bar. Finally, it is shown that both software packages are quite accurate and useful tools for the prediction of hydrate for simple systems. However, HydraFlash can simulate more complex systems, including different types of salts at higher pressures. Investigation results indicate insightful guidance for accurately predicting hydrate dissociation under simulated conditions. / The authors would also like to thank the Turkish National Agency for offering an Erasmus student grant for Mr. Nejmi Söyler under the Erasmus+ Program Action 1 throughout the training period.

Yes / Polymorphism in active pharmaceutical ingredients (APIs) can be regarded as critical for the potential that crystal form can have on the quality, efficacy and safety of the final drug product. The current contribution aims to characterize thermodynamic interrelationship of a dimorphic co-crystal, FI and FII, involving carbamazepine (CBZ) and saccharin (SAC) molecules. Supramolecular synthesis of CBZ-SAC FI and FII have been performed using thermo-kinetic methods and systematically characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), solubility and slurry measurements. According to Berger and Ramberger’s heat of fusion rule, FI (ΔHfus = 121.1 J/g, mp 172.5 °C) and FII (ΔHfus= 110.3 J/g, mp 164.7 °C) are monotropically related. The solubility and van’t Hoff plot results suggest that FI stable and FII metastable forms. This study reveals that CBZ-SAC co-crystal phases, FI or FII, could be stable to heat induced stresses, however, FII converts to FI during solution mediated transformation. / Authors would like to acknowledge UKIERI (TPR 26), EPSRC (EP/J003360/1, EP/L027011/1) for the support. Open Access funded by Engineering and Physical Sciences Research Council

The recent development of tool steels and high-speed steels has led to a significant increase in alloy additions, such as Co, Cr, Mo, N, V, and W. Knowledge about the phase relations in these multicomponent alloys, that is, the relative stability between different carbides or the solubility of different elements in the carbides and in the matrix phase, is essential for understanding the behaviour of these alloys in heat treatments. This information is also the basis for improving the properties or designing new alloys by controlling the amount of alloying elements. Thermodynamic calculations together with a thermodynamic database is a very powerful and important tool for alloy development of new tool steels and high-speed steels. By thermodynamic calculations one can easily predict how different amounts of alloying elements influence on the stability of different phases. Phase fractions of the individual phases and the solubility of different elements in the phases can be predicted quickly. Thermodynamic calculations can also be used to find optimised processing temperatures, e.g. for different heat treatments. Combining thermodynamic calculations with kinetic modelling one can also predict the microstructure evolution in different processes such as solidification, dissolution heat treatments, carbide coarsening, and the important tempering step producing secondary carbides. The quality of predictions based on thermodynamic calculations directly depends on the accuracy of the thermodynamic database used. In the present work new experimental phase equilibria information, both in model alloys containing few elements and in commercial alloys, has been determined and was used to evaluate and improve the thermodynamic description. This new experimental investigation was necessary because important information concerning the different carbide systems in tool steels and high-speed steels were lacking. A new thermodynamic database for tool steels and high-speed steels, TOOL05, has been developed within this thesis. With the new database it is possible to calculate thermodynamic properties and phase equilibria with high accuracy and good reliability. Compared with the previous thermodynamic description the improvements are significant. In addition the composition range of different alloying elements, where reliable results are obtained with the new thermodynamic database, have been widened significantly. As the available kinetic data did not always predict results in agreement with new experiments the database was modified in the present work. By coupling the new thermodynamic description with the new kinetic description accurate diffusion simulations can be performed for carbide coarsening, carbide dissolution and micro segregation during solidification. / QC 20100929