Dynamical heterogeneity (DH) has been observed in many systems approaching the glass or jamming transition. Whether DH has a structural origin is under heated debate. To provide a deeper understanding, in this thesis I investigate the microscopic dynamics in weakly attractive colloidal systems by confocal fluorescence microscopy. The van Hove density-density correlation function is applied to our systems. Separable fast and slow populations emerge in the self part (svH), while the distinct part shows a strong signature of DH close to the gel transition. At intermediate time, svH shows a purely exponential tail, mainly arising from the fast population. I show that this broad tail is a direct consequence of the occurrence of rare large jumps that are statistically distributed. The slow population tends to form a space-spanning backbone, and its mean squared displacement close to the gel transition exhibits a plateau, whose height is consistent with the range of attraction, suggesting a bonding mechanism for the dynamical arrest. I further examine various quantities characterizing local structure and local dynamics and a strong correlation is identified between them. Subsequently, I develop order parameters for quantifying amorphous structure and apply them to our systems. I find that attractive colloidal systems exhibit higher order under higher attraction tension, while hard spheres become more ordered under higher compression. Finally, I investigate the effect of the range of attraction on the structure and dynamics of attractive colloidal systems. I observe that the system with shorter range of attraction forms a denser and more heterogeneous structure. Meanwhile, I observe an even stronger dynamical heterogeneity. These observations provide further evidence of a connection between structural heterogeneity and dynamical heterogeneity in these systems, providing guidance for a theoretical description of the dynamical arrest as well as the relaxation mechanisms upon gelation and its relation to solidification in glasses. / In order to do all of this, I first implemented full 3D subpixel resolution localization of particles and improved particle tracking algorithms tailored for the sorts of heterogenous dynamics these systems exhibit, that otherwise confounds existing methods such that the very relaxation mechanisms would be missed. This allows us to obtain unprecedented precision in positions of all of the particles and complete tracking, both of which are essential for correctly determining system properties that depend on measured particle dynamics.

The development of portable equipments, wireless sensors networks and self-powered devices in a general manner generates a strong demand for micro-energy harvesting devices. One of the most challenging ways to self power devices is the development of systems that recycle ambient energy and continually replenish the energy consumed by the system. Apart from electromechanical energy harvesting, it is also interesting to convert thermal energy, which is "available" everywhere, into suitable electrical energy. In this thesis, the thermal to electrical energy conversion from temperature fluctuations was developed and improved, and the feasibility of this technique was also confirmed by implementing the experimental experiment. Among different ferroelectric materials, PZN-4.5PT single crystal and P(VDF-TrFE-CFE) 61.3/29.7/9 mol% were chosen as active materials due to their outstanding properties under electric field. By means of some intelligent thermodynamic cycles, e.g., Ericsson or Stirling cycle, which has been presented in previous research, the efficiency of energy conversion could be improved greatly. In the first part, pyroelectric energy harvesting on PZN-4.5PT single crystals with an Ericsson cycle was mainly investigated from two aspects: frequency effect and phase transitions. It was shown that the harvested energy demonstrated a nonlinear decrease with an increase of frequency, and the optimal use of the phase transitions during the Ericsson cycle could greatly improve the harvested energy by choosing the appropriate working temperature range. Based on it, two asymmetric Ericsson models (L-H and H-L cycles) were attempted successfully, and it was confirmed that the H-L cycle is the most effective thermal energy harvesting cycle for this material. The second part concentrated on electrostatic energy harvesting by nonlinear capacitance variation on P(VDF-TrFE-CFE) 61.3/29.7/9 mol% terpolymer. Ericsson cycle was tested experimentally between 25 and 0°C and compared with the simulation from dielectric constant values obtained under DC electric field. The identical result between simulation and experiment proved the reliability of our theoretical evaluation. It was found, from simulation, that the harvested energy increased up to 240 mJ/cm3 when raising the electric field at 80 kV/mm. The further study on Ericsson and Stirling cycle was also made under different temperature and electric field conditions for evaluation. The harvested energy increases with the rising of temperature variation and electric field in both cycles, but in contrast to Ericsson cycle, Stirling cycle can harvest more energy for the same injected energy.

The focus of the present research is to find the relative thermodynamic stability of ?-boron and ?-boron via heat capacity measurements. Efforts to synthesize ?-boron through the application of vapour-liquid-solid theory resulted in the discovery of a new chemical vapour deposition approach. The heat capacities of both synthesized ?-boron and commercial (99.5%) ?-boron were determined using relaxation calorimetry over the temperature range 0.2 K to 400 K. These data, in combination with literature information, allowed the calculation of the Gibbs energy of the ?-boron to ?-boron transition from 0 K to 1985 K. It was found that the transition from ?-boron to ?-boron was thermodynamically favourable at all temperatures up to 1985 K with a value of ?Gt(T = 300 K) = -10 kJ mol-1 ± 1 kJ mol-1 and ?Gt(T = 1985 K) = -15 kJ mol-1 ± 1 kJ mol-1.

Karboanhidrazės (CA) yra metalofermentai, katalizuojantys virsmus tarp anglies dioksido ir bikarbonato. Jų slopinimas gali būti taikomas gydyti tokias skirtingas ligas kaip glaukoma, vėžys, nutukimas, epilepsija, osteoporozė ir kt. Šiuo metu yra beveik 30 mažamolekulinių junginių, kurie naudojami kaip vaistai, su padidėjusiu karboanhidrazių aktyvumu susijusioms ligoms gydyti. Darbe tirta rekombinantinių žmogaus karboanhidrazių I, II, VII, IX ir XIII sąveika su sulfonamidiniais ligandais. Įvertintas tirtų baltymų stabilumas skirtingomis eksperimentinėmis sąlygomis, nustatyta priešvėžinio taikinio CA IX oligomerinė būsena. Modeliniais baltymais naudojant karboanhidrazes, praplėstos terminio poslinkio metodo taikymo ribos. Išmatuoti 40 naujų susintetintų junginių sąveikos su karboanhidrazėmis termodinaminiai parametrai, išanalizuota CA XIII sąveikos su sulfonamidiniais slopikliais termodinamika, atskiriant tikruosius, nuo eksperimento sąlygų ir susijusių reakcijų nepriklausančius jungimosi parametrus. / Carbonic anhydrases (CAs) are metalloenzymes that catalyze the conversion between carbon dioxide and bicarbonate. Their inhibition can be applied for treatment of different diseases, such as glaucoma, cancer, obesity, epilepsy, osteoporosis, etc. There are nearly 30 small molecule ligands that are used as drugs for carbonic anhydrase related diseases. In this work interaction between recombinant human carbonic anhydrases I, II, VII, IX, XIII and sulfonamide ligands was analysed. Stability of selected carbonic anhydrases was evaluated in different experimental conditions. Oligomeric structure of anticancer target CA IX was determined. Using carbonic anhydrases as model proteins, the application range of thermal shift assay was extended. Binding parameters of 40 new compounds to human carbonic anhydrases were measured. The binding thermodynamics of sulfonamide ligands to CA XIII was analyzed and intrinsic binding parameters, independent of the experimental conditions and linked protonation reactions, were determined.

Carbonic anhydrases (CAs) are metalloenzymes that catalyze the conversion between carbon dioxide and bicarbonate. Their inhibition can be applied for treatment of different diseases, such as glaucoma, cancer, obesity, epilepsy, osteoporosis, etc. There are nearly 30 small molecule ligands that are used as drugs for carbonic anhydrase related diseases. In this work interaction between recombinant human carbonic anhydrases I, II, VII, IX, XIII and sulfonamide ligands was analysed. Stability of selected carbonic anhydrases was evaluated in different experimental conditions. Oligomeric structure of anticancer target CA IX was determined. Using carbonic anhydrases as model proteins, the application range of thermal shift assay was extended. Binding parameters of 40 new compounds to human carbonic anhydrases were measured. The binding thermodynamics of sulfonamide ligands to CA XIII was analyzed and intrinsic binding parameters, independent of the experimental conditions and linked protonation reactions, were determined. / Karboanhidrazės (CA) yra metalofermentai, katalizuojantys virsmus tarp anglies dioksido ir bikarbonato. Jų slopinimas gali būti taikomas gydyti tokias skirtingas ligas kaip glaukoma, vėžys, nutukimas, epilepsija, osteoporozė ir kt. Šiuo metu yra beveik 30 mažamolekulinių junginių, kurie naudojami kaip vaistai, su padidėjusiu karboanhidrazių aktyvumu susijusioms ligoms gydyti. Darbe tirta rekombinantinių žmogaus karboanhidrazių I, II, VII, IX ir XIII sąveika su sulfonamidiniais ligandais. Įvertintas tirtų baltymų stabilumas skirtingomis eksperimentinėmis sąlygomis, nustatyta priešvėžinio taikinio CA IX oligomerinė būsena. Modeliniais baltymais naudojant karboanhidrazes, praplėstos terminio poslinkio metodo taikymo ribos. Išmatuoti 40 naujų susintetintų junginių sąveikos su karboanhidrazėmis termodinaminiai parametrai, išanalizuota CA XIII sąveikos su sulfonamidiniais slopikliais termodinamika, atskiriant tikruosius, nuo eksperimento sąlygų ir susijusių reakcijų nepriklausančius jungimosi parametrus.

In this thesis, aspects of the physics of black holes are reviewed and new results in black hole thermodynamics are presented. First, general black hole solutions of Einstein’s equations of general relativity are mentioned and a proof of conservation law of energy and momentum in general relativity is presented. Aspects of the laws of black hole mechanics and Hawking radiation are then studied. Two proposals which attempt to explain the origin of black hole entropy (the brick wall model and entanglement entropy) are then discussed. Finally, some recent work related to the possible production and detection of black holes in colliders is presented. / viii, 141 leaves ; 29 cm.

The thesis involves a study of the thermodynamics of ternary liquid mixtures involving carboxylic acids with nitriles, hydrocarbons including cycloalkanes, and water. Carboxylic acids are an important class of compounds with a great number of industrial uses and applications. In many parts ofthe world the separation of carboxylic acids (in particular acetic and propanoic acid) is an important and desirable task. In South Africa, these carboxylic acids together with many other oxygenates and hydrocarbons are produced by SASOL using the Fischer - Tropsch process. The separation of these acids from hydrocarbons and from water is a commercially lucrative consideration, and is the raison d' etre for this study. The work focussed on the use of nitriles in effecting separation by solvent extraction and not by the more common method of distillation. The nitrile compounds were chosen because of their high polarity. The carboxylic acids used in this study always refer to: acetic acid, propanoic acid, butanoic acid, 2-methylpropanoic acid, pentanoic acid and 3-methylbutanoic acid. The first part of the experimental programme is devoted to the determination of excess molar volumes of mixtures of (a carboxylic acid + nitrile compound), where the nitrile refers to acetonitrile, butanenitrile or benzonitrile, respectively. Densimetry was used to determine the excess molar volumes. The work was done in order to get some idea of the interactions involved between a carboxylic acid and a nitrile. The second part of the experimental study is concerned with the determination of excess molar enthalpies of mixtures of( a carboxylic acid + nitrile compound), where the nitrile refers to acetonitrile, butanenitrile or benzonitrile, respectively. The excess molar enthalpies were determined using flow microcalorimetry Again, this work was done in order to gain some insight into the interactions involved between a carboxylic acid and a nitrile. The third part of the experimental work consists ofternary liquid-liquid equilibria of mixtures of (acetonitrile + a carboxylic acid + heptane or cyclohexane), (benzonitrile + a carboxylic acid + water); and (butanenitrile + a carboxylic acid + water), at 298.15 K. The purpose was to investigate the use of nitriles as solvent extractors in separating carboxylic acids from hydrocarbons and also carboxylic acids from water. Ternary liquid-liquid equilibrium data are essential for the design and selection of solvents used in the liquid-liquid extraction process. The final section deals with the fitting of models of liquid mixtures to the experimental data collected in this work. The NRTL (Non-random, two liquid), UNIQUAC (Universal quasichemical), and FBT (Flory-Benson-Treszczanowicz) models were used. The modelling work served three purposes: • to summarise the experimental data • to test theories of liquid mixtures • prediction of related thermodynamic properties / Thesis (Ph.D.)-University of Natal,Durban, 2003.

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