The climatology of the seasonal cycle of water mass variation and transformation in Bass Strait, south-eastern Australia, is studied using a high resolution three-dimensional sigma-coordinate hydrodynamic model coupled with data from observations and previous studies. Model forcing consists of the principal tidal constituents from the Australian National Tidal Centre and long-term monthly mean atmospheric forcing fields from NCEP reanalysis. The initial density field is established using temperature and salinity means and annual and semi-annual harmonics from the CARS2000 hydrographic atlas. This is also used to prescribe incoming water mass properties at model open-sea boundaries with seasonal variation. Far-field forcing is included with open-sea boundary parameterisation of residual sea-level representing both the South Australian Current and the East Australian Current. Lagrangian and Eulerian tracer methods are used to derive transport timescales, such as age, residence times and flushing times. These are used to examine and summarise model predictions and as a diagnostic tool in sensitivity studies. Currents, sea-level and water mass properties in the model compare favourably with previous studies and observations, despite limitations in the model and in the data used for comparison. The seasonal cycle, in model results, is characterised by formation of a shallow (< 20 m) saltier surface-layer in late spring to summer and subsequent downward mixing and erosion of the salinity field in autumn to winter with water mass from the west. This leaves behind water mass with positive age and salinity anomalies in areas of low flushing. In late winter-early spring most parts of this water mass leave the Strait interior. These areas are thought to be related to the source water of the Bass Strait Cascade. The residual circulation in all model experiments is shown to be related to seasonal-mean sea-level anomalies, arising from both barotropic and baroclinic adjustment, both in and surrounding the Strait.

This Masetr thesis looks into weathering pits of nature park Česká Kanada. The theoretical part of the thesis investigates research of weathering pits done in the Czech Republic as well as abroad. The practical part deals with weathering pit-bearing as well as weathering pitabsent blocks of rock within the study area. It describes their geological-geomorphological environment and attempts to find differences between the weathering pit-bearing and absent blocks (the presence of cracks, altitude, landforms, shape of the rock block and more). Furthermore it was established that a suitable rock block morphology (respectively the existence of horizontal plane) is important for formation of weathering pits. It also studies water properties in selected weathering pits, relationship of overhangs to prevailing wind directions. A correlation between overhang and wind direction was found in sense that NW to W winds correspond with overhang formation on eastern sides of weathering pits. Water in weathering pit of Čertův kámen located in sunny bare landscape shows significantly different properties in comparison with water properties of remaining weathering pits located in forrested areas.

Dans cette thèse, les propriétés de l'eau en présence d'ions dans des nanoconfinement à base de silice ont été étudiées. L'objectif principal est de relier ces propriétés à l'évolution des matériaux mésoporeux de silice dans les solutions aqueuses. Pour atteindre cet objectif, nous avons utilisé une approche originale consistant à remplir avec des solutions électrolytiques comportant des ions ayant des propriétés kosmotropes différentes, XCl2 (X = Ba, Ca, Mg) des systèmes modèles tels que deux surfaces de silice parallèles et planes espacées de 3 et 5 nm (nanocanaux) et des silices à mesoporosité ordonnée comme les silices SBA-15 (6 nm de taille pores et murs des pores microporeux) et MCM-41 (3 nm de taille de pores et murs des pores denses).Les résultats obtenus indiquent que la cinétique de remplissage des nanocanaux dépend de la taille du confinement, de la nature des ions et de la solubilité des sels associés aux électrolytes. Dans certains cas, le remplissage incomplet des nanocanaux peut s'expliquer par une diminution de la dynamique de l'eau associée à l’atteinte de la saturation vis-à-vis des sels XCl2 dans la couche interfaciale. La possible précipitation de phases XCl2 pourrait permettre d’expliquer le bouchage de certains nanocanaux. Par la suite, les propriétés de l'eau dans des nanoconfinement concave de silice tels que les cylindres ont également été étudiées. La structure de l’eau en présence d’ions et sa dynamique à l’échelle de la picoseconde caractérisées respectivement par FTIR-ATR et diffusion quasi élastique des neutrons, ont été analysées. Les résultats suggèrent que les propriétés structurales et dynamiques de l'eau sont fortement influencées par la taille du confinement, le caractère kosmotrope des ions et l'excès d'ions dans la couche interfaciale.Enfin, nous avons déterminé l’évolution des deux silices mésoporeuses dans des solutions électrolytiques par diffusion des rayons X aux petits angles. Pour une taille de pore de 3 nm et des murs de pores denses (MCM-41), une dynamique de l’eau lente à une échelle picoseconde conduit probablement à une sursaturation des ions dans la couche interfaciale et donc à une reprécipitation des sels XCl2 et / ou de la silice plus stable. Dans ce cas, l'évolution du MCM-41 est induite par un processus de dissolution-recondensation / précipitation. Dans les plus grands mésopores du SBA-15, en raison de la microporosité dans la paroi des pores, le processus d'altération est différent. Dès le début, une couche d'altération se forme et la taille des pores augmente jusqu'à saturation de la silice. Par la suite, un processus de recondensation / précipitation similaire à celui observé dans la MCM-41 se produit dans la microporosité. Ces deux types d'évolutions en silice pourraient persister jusqu'à l'obtention d'une phase de silice thermodynamiquement stable. / In this study, we investigated the water properties in the presence of ions in silica nanoconfinement. The main objective is to relate these water properties to the evolution of silica mesoporous materials in aqueous solutions. To reach this goal, we used an original approach, consisting in the use of electrolyte solutions having ions with various kosmotropic property XCl2 (X = Ba, Ca, Mg) confined in model systems such as two parallel and plane silica surfaces spaced of 3 and 5 nm (nanochannels) and highly ordered mesoporous silica materials represented by SBA-15 (6 nm pore size and microporous pore wall) and MCM-41 (3 nm pore size and dense pore wall).The obtained results indicate that the filling kinetics in nanochannels is driven by the size of the confinement, the nature of ions and the salt solubility of electrolytes. In some cases, the incomplete filling of the nanochannels may be explained by a decrease of water dynamics associated to the saturation of XCl2 salts into the interfacial layer. The possible precipitation of XCl2 phases may explain an incomplete filling by a nanochannels clogging.Thereafter, the water properties in nanoconfinement made of silica concave surface such as cylinders were studied. The water structure and dynamics at a picosecond scale in presence of ions were respecteively characterized by infrared spectroscopy and quasi-elastic neutron scattering. The results suggest that the structural and dynamical water properties are strongly affected by the size of the confinement, the kosmotropic properties of ions and the surface ion excess in the interfacial layer.Finally, we characterized the evolution of the two mesoporous silica in electrolyte solutions using in-situ small-angle X-ray scattering. For 3 nm pore size and dense pore wall (MCM-41), the slow dynamics at a picosecond scale probably lead to a supersaturation of ions in the interfacial layer and thus, to a reprecipitation of XCl2 salts and/or silica phases. In that case, the evolution of the MCM-41 is driven by a dissolution-recondesation/precipitation process. In the bigger mesopores of SBA-15, due to the microporosity in the pore wall, the alteration process is different. During a first stage, an alteration layer is formed and the pore size increases until the silica saturation. Afterwards, a similar recondensation/precipitation process as observed in MCM-41 occurs into the microporosity. These two types silica evolutions could persist until the formation of a thermodynamic stable silica phase.

Hydration is known to be crucial in biomolecular interactions including ligand binding and self-assembly. In our earlier studies we have shown the key role of water in stabilizing the specific parts of the collagen triple helix depending on the imino acid content. We further showed that the primary hydration shell around collagen could act as a lubricating layer aiding in collagen assembly. But key details on the structure and dynamics of water near protein surfaces and its role in protein-protein interactions remain unclear. In the current study we have developed a novel method to analyze hydration maps around peptides at 1-A resolution around three self-assembling lament systems with known structures, that respectively have hydrated (collagen), dry non-polar and dry polar (amyloid) interfaces. Using computer simulations, we calculate local hydration maps and hydration forces. We find that the primary hydration shells are formed all over the surface, regardless of the types of the underlying amino acids. The weakly oscillating hydration force arises from coalescence and depletion of hydration shells as two laments approach, whereas local water diffusion, orientation, or hydrogen bonding events have no direct effect. Hydration forces between hydrated, polar, and non-polar interfaces differ in the amplitude and phase of the oscillation relative to the equilibrium surface separation. Therefore, water-mediated interactions between these protein surfaces ranging in character from ‘hydrophobic’ to ‘hydrophilic,’ have a common molecular origin based on the robustly formed hydration shells, which is likely applicable to a broad range of biomolecular assemblies whose interfacial geometry is similar in length scale to those of the present study. In a related study through simulations we show that the rate of tissue optical clearing by chemical agents correlated with the preferential formation of hydrogen bond bridges between agent and collagen. Hydrogen bond bridge formation disrupts the collagen hydration layer and facilitates replacement by a chemical agent to destabilize the tertiary structure of collagens thereby reducing light scattering. This study suggests that the clearing ability of an alcohol not only depends on its molecular size, but also on the position of hydroxyl groups on its backbone.

This thesis deals with several aspects of translational and reorientational dynamics of water molecules confined inside narrow carbon nanotubes. Water molecules confined in a non-polar, nanoscopic pore exhibit extremely unusual structural and dynamical properties. Adding to the list of anomalies which are already present in bulk liquid water, the confined water “chains” and “shells” springs many more surprises. The relatively weak interaction with the surrounding walls in conjuction with the strong inter-water hydrogen bonds lead o several novel structural and dynamical features, very special to this “strange” phase of water. In this thesis, we present our findings on the detailed molecular level description of translational and reorientational dynamics of this novel phase of anomalously “soft” water. Chapter 1 introduces the varied theoretical, numerical and experimental attempts to demystify the properties of bulk, interfacial and confined water. It also motivates the aspects of diffusion in low dimensional systems, which are often termed “anomalous”. In Chapter 2, we study the structure and dynamics of water molecules inside an open ended carbon nanotube placed in a bath of water molecules. The size of the nanotube allows only a single file of water molecules inside the nanotube. The water molecules inside the nanotube show solid-like ordering at room temperature, which we quantify by calculating the pair correlation function. It is shown that even for the longest observation times, the mode of diffusion of the water molecules inside the nanotube is Fickian and not sub-diffusive. We also propose a one-dimensional random walk model for the diffusion of the water molecules inside the nanotube. We find good agreement between the mean-square displacements calculated from the random walk model and from MD simulations, thereby confirming that the water molecules undergo normal-mode diffusion inside the nanotube. We attribute this behavior to strong positional correlations that cause all the water molecules inside the nanotube to move collectively as a single object. The average residence time of the water molecules inside the nanotube is shown to scale quadratically with the nanotube length. In Chapter 3, we study the diffusion of water molecules confined inside narrow (6,6) carbon nanorings. The water molecules form two oppositely polarised clusters. It is shown that the effective interaction between these two clusters is repulsive in nature. The computed mean-squared displacement (MSD) clearly shows a scaling with time, which is consistent with single file diffusion (SFD). The time up to which the water molecules undergo SFD is shown to be the lifetime of the water molecules inside these clusters. The inter-cluster repulsive interactions are electrostatic and hence long-ranged, which is in complete contrast with shorter ranged steric repulsion in other systems which exhibit SFD. In Chapter 4, we study the anisotropic orientational dynamics of water molecules confined in narrow carbon nanotubes and nanorings. We find that confinement leads to strong anisotropy in the orientational relaxation. The relaxation of the aligned dipole moments, occurring on a timescale of nanoseconds, is three order of magnitude slower than that of bulk water. In contrast, the relaxation of the vector joining the two hydrogens is ten times faster compared to bulk, with a timescale of about 150 femtoseconds. The slow dipolar relaxation is mediated by the hopping of orientational defects, which are nucleated by the water molecules outside the tube, across the linear water chain. In Chapter 5, we study the reorientational dynamics of water molecules confined inside narrow carbon nanotubes immersed in a bath of water. Our simulations show that the confined water molecules exhibit bistability in their reorientational relaxation, which proceeds by angular jumps between the two stable states. The energy barrier between these two states is about 2kBT. The effect of non-Markovian jumps shows up in the ratio of the timescales o the first and second order reorientational correlation functions, which exceeds the value of the ratio in the diffusive limit. The analytical solution of a proposed model is also presented, which qualitatively explains this “unusual” relaxation. These results will have important implications in understanding proton conduction in water-filled ion channels. In Chapter 6, we report the thermodynamic aspects of the translational and re-orientational dynamics of the strongly confined water molecules. Considering the energetics it is surprising that the water molecules spontaneously fill up the nanotube. Thus the thermodynamics of entry of water molecules in the hydrophobic cavity of nanotube. This is generally attributed to the rotational entropy gain by the water molecules on entering the tube, a fact which has not been demonstrated quantitatively so far. We show that the gain in rotational component of the entropy compensates the loss of energy of the water molecules upon entering the nanotube. In Chapter 7, we conclude by summarising the work done in the previous chapters and discuss the future course of actions. We would like to extend the studies on the diffusion of water inside finite nanotubes in the presence of bathwater outside, to nanotube lengths, where it is possible to observe the cross-over from an initial “single file” to and eventual, centre of mass dominated, “normal” diffusion. The mean field estimate of the length of the nanotube required so that one observes a crossover from the initial “single file” to “normal” diffusion at 100 ps is about 700 ˚A. Simulation of such a system would possibly provide an unambiguous answer to the question, whether it is possible to observe SFD in finite carbon nanotubes, filled with water. Regarding the reorientational dynamics, we would like to extend our understanding of the reorientational relaxation of water chains to more more complicated structures. Depending on the diameter of the confining nanotube water molecules form polygons of ice. In the present situation each water molecule can be in only two possible states of orientation. Hence, it would be interesting to predict the reorientational dynamics for other ice structures, where each water molecule can be more “orientational states”. In Chapter 8, we report a work which is unrelated to the rest of this thesis. The work has been done in collaboration with Prof. T. V. Ramakrishnan and Prof. Vijay B. Shenoy. We report a novel method for the calculation of elastic constants of a solid in the frame work of Ramakrishnan-Youssouf density functional theory. The structural aspect of the liquid to solid transition and how it affects the elastic constants of the solids is brought out very clearly. The calculation is analytical and we obtain explicit expressions for the elastic constants. The description of the solid is in terms of the structure factor, S(G), of the coexisting liquid. The elastic constants are expressed as a function of equilibrium parameters, such as c(0), relatedto the compressibility of the liquid. Another important quantity on which the elastic constants depend is the curvature, c"(|G|), of c(|q|)curve at its peak (q= G). These quantities are known experimentally for many systems, and can also be calculated accurately. The shear modulus depends only on c"(|G|), while the bulk modulus has contributions from both c"(|G|) and c(0). The obtained elastic constants do not satisfy the Cauchy relations, in that C12 is not equal to C44. Calculations have been performed for two-dimensional square and triangular lattices as well as bcc and fcc lattices in three dimensions. It is seen that in order to get good agreement between the theoretical and the experimental results of the elastic constants, three body correlations have to be introduced in the calculations for the bcc and the fcc lattices. For the last, in which two shells of reciprocal lattice vectors are appropriate, we point out the modifications needed for choosing the lattice parameter in the unstrained freezing problem. We obtain a new, first principles, quasiuniversal relation for elastic constants, scaled by the melting temperature, that is experimentally satisfied. It is similar to the famous Verlet criterion that S(|G|) = 2.9 at freezing and is free of some of the unphysical aspects of previous work.

This master `s thesis deals about the dielectric properties of water. It describes the basic chemical and physical properties of water and its distribution in terms of structure. It also describes the basic parameters of distilled water, deionized and superclean. In the chapter number 5 described the behavior of dielectrics in an electric field, determining the dipole moment by Claus-Mossotti 'equation, measurement of permittivity and loss factor. Practical part is consists of the design of the electrode systém, of measuring the water quality and evaluation of measured data

Orientador: David Mendez Soares / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-17T17:51:55Z (GMT). No. of bitstreams: 1 Gomide_AndrezaBarbosa_D.pdf: 5782130 bytes, checksum: 73ea74eba4132f68eced1394071826de (MD5) Previous issue date: 2011 / Resumo: Frente à complexidade estrutural e funcional das membranas biológicas, a construção de membranas modelo sobre suporte sólido surge como uma resposta para o estudo daquelas. Para acessar as propriedades estruturais e funcionais de uma membrana biológica é fundamental que a membrana modelo seja capaz de refletir a interface membrana/ambiente aquoso. Portanto, foi feito um estudo da água frente à superfície sólida e verificou-se que a água frente a superfícies pode apresentar estrutura e propriedades físicas como densidade, viscosidade, constante dielétrica, etc. diferentes da águas da massa líquida (bulk water). Também investigamos a formação de filmes de fosfolipídios sobre o eletrodo de ouro a partir de soluções de lipossomos. A microbalança de cristal de quartzo (QCM) mostrou os processos de adsorção de lipossomos à superfície do eletrodo de ouro, de ruptura e formação de filmes. Usando a técnica de filmes de Langmuir, determinamos a densidade de fosfolipídios em uma membrana modelo e comparamos com os resultados gravimétricos obtidos com a QCM. Com a técnica de miscroscopia de força atômica (AFM) usando medidas de força vs. distância, detectamos a espessura do filme de DMPC (6 nm). Além disso, mostramos que na presença de uma solução 0,5 M de H2SO4 o filme formado apresenta uma rugosidade na superfície que muda conforme o potencial aplicado ao eletrodo / Abstract: Faced with structural and functional complexity of biological membranes, the construction of model membranes on solid support appears as a response to the study of those. To access the structural and functional properties of a biological membrane, it is crucial that the membrane model is able to reflect the interface membrane/aqueous environment. Therefore, a study was made of water contacting a solid surface. It was found that water close to surfaces can have structure and physical properties (as density, viscosity, dielectric constant, etc..) different from bulk water. We also investigated the formation of phospholipid films on the gold electrode from solutions of liposomes. The quartz crystal microbalance (QCM) showed the adsorption of liposomes to the surface of gold electrode, breakdown and formation of a film. Using the technique of Langmuir we determined the density of phospholipids in a membrane model and compared with the gravimetric results obtained with the QCM. With the atomic force microscope (AFM) using the force vs. distance measurement we detected a 6 nm thick DMPC film on the electrode. Furthermore, we showed that in the presence of a 0.5 M solution of H2SO4 the film formed on the surface has a roughness that changes with the applied potential to the electrode / Doutorado / Físico-Química / Doutora em Ciências

The main objective of presented thesis is to design a shower system in order to extend voltage tests by voltage wet testing. The introduction focuses on important aspects related to voltage wet testing. Such aspects originates mainly from Czech but also foreign standards. Following part of the thesis deals with specific wet testing design proposals, which fulfil the standards requirements. The final part of presented thesis is focused on partial experiments. Namely the analysis of rain water properties, behavior of rain drops exiting the nozzle with varying flow and nozzle angle, wet test on insulator in dry and wet conditions.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / Diatremes of Late Pliocene age in the Hopi Buttes area of Arizona are becoming increasingly important sources of groundwater to the Indian nations. These volcanic vent structures are prime sources of groundwater because sedimentary formations in the Hopi Buttes area yield only limited amounts of water or yield poor quality water. Diatremes act as traps for groundwater and some have yielded moderate amounts of good quality water to wells. Surface geologic investigations and analysis of drillers' logs indicate that structural relationships and diatreme lithology provide a means to project the hydrologic properties of the vent. Diatremes most suitable for groundwater development should have a diameter greater than one half mile, should contain volcanic tuff and breccia at its center, and should be fractured from collapse. Lava flows covering diatremes reduce recharge from sheet wash or from ephemeral stream flow. Data from geomagnetic and gravity surveys will be analyzed to determine its suitability for predicting subsurface size, shape, and lithology of the diatreme. The integration of geophysical and surface geologic data will reveal the total geometry of the structure enabling the most accurate appraisal of the hydrologic properties of the diatreme.