The majority of the Earths surface is covered with water, and the air-water interface (AWI) acts as the natural boundary between the atmosphere and the water. The AWI is an important ecological zone in natural aquatic habitats that governs transport of material and energy between bodies of water and the atmosphere. Little is known about temperature profiles and biological transport across the boundary layers at the air-water interface, and how wind interactions at the AWI affects them. New technologies such as sensors and unmanned surface vehicles (USV) need to be developed and used to address this knowledge gap. The goal of the research is to study population densities of the bacteria Pseudomonas syringae below, at and above the AWI using USV equipped with specialized sensors. The first specific objective was to map temperature profiles and resolve the boundary layer at the AWI using high resolution distributed temperature sensing (HR-DTS) on board an unmanned surface vehicle (USV). Our second research objective was to sample microbes from the water with a USV at multiple depths and locations. Our third research objective was to sample microbes from the atmosphere with a USV at the AWI. Our fourth research objective was to track and localize hazardous agents (tracer dyes) using a USV in aqueous environments. / Ph. D. / The majority of the Earths surface is covered with water, and the air-water interface (AWI) acts as the natural boundary between the atmosphere and the water. The AWI is an important ecological zone in natural aquatic habitats. Little is known about temperature profiles and biological transport across the boundary layers at the air-water interface, and new technologies need to be developed and used to address this knowledge gap. The specific objectives of the proposed work are to: (1) map temperature profiles and resolve the boundary layer at the AWI using high resolution distributed temperature sensing (HR-DTS) on board an unmanned surface vehicle (USV), (2) sample microbes from the water with a USV at multiple depths and locations, (3) sample microbes from the atmosphere with a USV at the AWI, and (4) track and localize hazardous agents (tracer dyes) using a USV in aqueous environments.

Approved for public release; distribution is unlimited / Variability of the MABL and its effect on the electromagnetic (EM) refractive structure around the Greenland Sea marginal ice zone were examined. Rawinsonde profiles and surface observations collected from 3 ships during MIZEX-87(20 March-11 April) served as the data set. A program, developed to calculate the refractivity at each vertical level of the rawinsonde profiles, also identified the levels at which trapping, superrefraction and subrefraction occurred. Temporal studies showed that a higher incidence of anomalous refractive layers occurred during periods when the region was under the influence of high pressure. More than 50% of the time, trapping and super-refractive layers were attributed to development of a capping inversion just above the MABL during these periods. Spatial studies showed that the refractive structure varied relative to distance from the ice edge as did the depth of the MABL. An upward slope in refractive layer heights was observed from the ice toward the open water. Significant spatial inhomogeneity was observed over horizontal ranges of less than 100 km. This was attributed to both the large-scale synoptic forcing affecting the region and to variations in the surface fluxes of heat and moisture over the ice and over the water. A range-dependent ray trace model developed at the Naval Ocean Systems Center was used to show how the ray paths of EM waves vary with a changing refractive structures. Keywords: Air water interactions, Greenland Sea, Atmospheric refraction, Electromagnetic wave propagation, Heat flux, Sea ice. Theses. (EDC) / http://archive.org/details/temporalspatialv00grot / Lieutenant, United States Navy

Apresenta-se um modelo matemático que avalia numericamente a estabilidade do estado estacionário para escoamentos água-ar em sistemas pipeline-riser de geometria variável. Uma análise a partir da teoria de estabilidade linear é aplicada a um modelo matemático adequado ao escoamento água-ar no sistema pipeline-riser. O modelo considera equações de continuidade para a fase líquida e para a fase gasosa, admite-se escoamento unidimensional e em condição isotérmica. O líquido é considerado incompressível enquanto que a fase gasosa é considerada um gás ideal. Admite-se uma equação de momento simplificada para mistura onde despreza-se a inércia (NPW - Modelo No Pressure Wave) e o padrão de escoamento local é definido com base nas condições do escoamento e na inclinação local. Assim, a intermitência severa é controlada principalmente pela gravidade no riser e pela compressibilidade do gás no pipeline. Tanto a correlação de fluxo de deriva quanto o cálculo da queda de pressão por atrito, adotados como lei de fechamento do modelo, são determinados em função do padrão de escoamento. Injeção de gás e válvula de choke são consideradas, respectivamente, na base e no topo do riser. O modelo é aplicado à sistemas pipeline-riser com escoamento água-ar citados na literatura. Os resultados da análise de estabilidade linear numérica são comparados aos resultados experimentais e numéricos apresentando uma excelente concordância. / A mathematical model that numerically evaluates the stability of the stationary state for hilly terrain air-water flows systems is presented. Numerical linear stability analysis is performed to a suitable mathematical model for the two-phase flows in a pipeline-riser system. The mathematical model considers the continuity equations for the liquid and gas phases, one-dimensional flow and isothermal conditions. The liquid is assumed incompressible while the gas phase is considered as an ideal gas. A simplified momentum equation for the mixture, neglecting inertia (NPW - No pressure wave model) is considered and the local flow pattern is defined based on the flow conditions and the local inclination. In this way, severe slugging is controlled mainly by gravity in the riser and compressibility in the pipeline. The void fraction and friction pressure drop, utilized as closure laws, are determined based on the local flow pattern. Gas injection at the bottom of the riser and a choke valve at the top are considered. The model is applied to air-water pipeline-riser systems reported in the literature. Numerical linear stability analysis results are compared with experimental and numerical results reported in the literature with excellent agreement.

Films of phospholipids and biologically relevant surfactants at the air-water interface provide a well-defined medium to study molecular alignment, phase behavior and interactions of biomembranes and lung surfactant with exogenous materials. Interactions between lung surfactant interfaces and solid particles are of particular interest due to the increased use of nanomaterials in industrial applications and the promise of polymeric particles in pulmonary drug delivery. Understanding such interactions is necessary to avoid potential adverse effects on surfactant function after exposure to particles. In this thesis, the mechanisms of surfactant inhibition after exposure to submicron particles via different routes were investigated. The effects of carboxyl-modified polystyrene particles (200 nm) on films of dipalmitoyl phosphatidylcholine (DPPC) and Infasurf (calf lung surfactant extract) were studied. Surfactants were exposed to different concentrations of particles in a Langmuir trough with symmetric surface compression and expansion. Surface tension, potential, microstructure and topology were examined to monitor particle effects on surfactant function. Several methods of surfactant exposure to particles were studied: particle injection into the subphase after spreading surfactant monolayers (subphase injection), mixing the particles with the subphase and spreading the surfactant on top (monolayer addition) and particle aerosolization onto surfactant films. Studies with DPPC monolayers revealed that particle-surfactant interactions are dependent on the particle introduction method. In the subphase injection method, particles did not penetrate the monolayer and no inhibitory effects on surfactant function were observed. However, in the monolayer addition method, particles caused a premature monolayer collapse and hindered surfactant respreading likely by penetrating into the DPPC monolayer. Finally, particle aerosolization on surfactant was performed to mimic the physiologically relevant route of surfactant exposure to particles. Particle aerosolization on DPPC monolayers significantly inhibited surfactant function in the lung-relevant surface tension range. When aerosolized on Infasurf, particles caused inhibitory effects as a function of time suggesting adsorption of surfactant components on particle surfaces as the main mechanism of interaction. This research will enhance understanding of the mechanisms of particle-induced surfactant dysfunction, thereby providing information for the safe design of polymeric particles for drug delivery and for developing guidelines for particles used in occupational settings.

The ultimate goal of this project has been to develop a computational model for quantifying the interactions between of a body of fluid and a fibrous surface. To achieve this goal, one has to develop a model to create virtual structures that resemble the morphology of a fibrous surface (Objective-1) as well as a model that can simulate the flow of a fluid over these virtual surfaces (Objective-2). To achieve the first objective, we treated fibers as an array of beads interconnected through viscoelastic elements (springs and dampers). The uniqueness of our algorithm lies in its ability to simulate the curvature of the fibers in terms of their rigidity, fiber diameter, and fiber orientation. Moving on to Objective-2, we considered woven screens for their geometric periodicity, as a starting point. We studied how fiber diameter, fiber spacing, and contact angle can affect the skin-friction drag of a submerged hydrophobic woven screen, and how such surfaces resist against water intrusion under elevated hydro-static pressures (a requirement for providing drag reduction benefits). We also studied the impact of surface geometry and wetting properties on droplet mobility over these surfaces. Laboratory experiment was conducted at various stages throughout this investigation, and good agreement was observed between the experimental data and the results from our numerical simulation.

Langmuir monolayers can be employed as simple model systems to study interactions at surfaces. Such investigations are important to fields ranging from biology to materials science. Herein, several aspects of these films and their associated water structure have been examined with vibrational sum frequency spectroscopy (VSFS). This second order nonlinear optical spectroscopy is particularly well suited for simultaneous investigations of the monolayer and the associated water structure with unprecedented surface specificity. The structures of these systems were altered through the control of experimental parameters including monolayer pressure, subphase temperature, pH and ionic content. Thermodynamic information about structural changes in a fatty amine monolayer's hydrophobic region was obtained by observation of the pressure and temperature dependence of the monolayer's solid to liquid phase transition. Further studies used the coordination of divalent cations to acid monolayers to perturb the water layers nearest to the film which enabled a better understanding of the water related VSFS features from these hydrophilic interfaces. Information from both the monolayer and water structure was then combined in order to examine the role of water in mediating ion-biomaterial interactions, often expressed in terms of the Hofmeister series.

Ein neues, verallgemeinertes Modell für Blasenkoaleszenz und –zerfall wurde entwickelt. Es basiert auf physikalischen Überlegungen und berücksichtigt verschiedene Mechanismen, die zu Blasenkoaleszenz und –zerfall führen können. In einer ausführlichen Literaturrecherche wurden zunächst die verfügbaren Modelle zusammengestellt und analysiert. Es zeigte sich, dass viele widersprüchliche Modelle veröffentlicht wurden. Keins dieser Modelle erlaubt die Vorhersage der Entwicklung der Blasengrößenverteilungen entlang einer Rohrströmung für einen breiten Bereich an Kombinationen von Volumenströmen der Gas- und der Flüssigphase. Das neue Modell wurde ausführlich in einem vereinfachten Testsolver untersucht. Dieser erfasst zwar nicht alle Einzelheiten einer sich entlang des Rohres entwickelten Strömungen, erlaubt aber im Gegensatz zu den CFD-Simulationen eine Vielzahl von Variationsrechnungen zur Untersuchung des Einflusses einzelner Größen und Modelle. Koaleszenz und Zerfall kann nicht getrennt von anderen Phänomenen und Modellen, die diese widerspiegeln, betrachtet werden. Es bestehen enge Wechselwirkungen mit der Turbulenz der Flüssigphase und dem Impulsaustausch zwischen den Phasen. Da die Dissipationsrate der turbulenten kinetischen Energie ein direkter Eingangsparameter für das neue Modell ist, wurde die Turbulenzmodellierung besonders genau untersucht. Zur Validierung des Modells wurde eine TOPFLOW-Experimentalserie zur Luft-Wasser-Strömungen in einem 8 m langen DN200-Rohr genutzt. Die Daten zeichnen sich durch eine hohe Qualität aus und wurden im Rahmen des TOPFLOW-IIVorhabens mit dem Ziel eine Grundlage für die hier vorgestellten Arbeiten zu liefern, gewonnen. Die Vorhersage der Entwicklung der Blasengrößenverteilung entlang des Rohrs konnte im Vergleich zu den bisherigen Standardmodellen für Blasenkoaleszenz und -zerfall in CFX deutlich verbessert werden. Einige quantitative Abweichungen bleiben aber bestehen. Die vollständigen Modellgleichungen sowie eine Implementierung über „User-FORTRAN“ in CFX stehen zur Verfügung und können für weitere Arbeiten zur Simulation polydisperser Blasenströmungen genutzt werden.

This study investigated the concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the particulate and dissolved phase, as well as concentrations of PAHs in the sediment in Kaohsiung Harbor lagoon. Sources of PAHs in the water column were determined by isomer ratios, hierarchical cluster analysis (HCA) and principal components analysis (PCA). The net and annual fluxes of PAHs were calculated after a lagoon-wide water sampling campaign and compared with those found in a previous study (Fang, 2007) in which data from only one water sampling station was used. ¡@¡@In rain season, total PAH concentrations ranged from 21.6 to 36.2 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 15.5 to 27.2 ng/L and from 3.4 to 8.6 ng/L, respectively. In dry season, total PAH concentrations ranged from 13.2 to 31.5 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 8.0 to 21.1 ng/L and from 5.3 to 10.5 ng/L, respectively. Total PAH concentrations were found higher in rain season than in dry season. The highest total PAH concentration in dry season was observed in Chianjen River estuary. Relatively high PAH concentrations were also observed in these southern stations of Kaohsiung Harbor because of their location near Dalin industrial park. Total PAH concentrations ranged from 81.7 to 2279 ng/g for sediment samples, with average of 895 ng/g. The correlations between PAH concentrations and organic carbons, water temperature, salinity and suspended particles were also examined in this study. PAH concentration in dissolved phase was negatively correlated with water temperature (p<0.05). PAH concentration in sediment was positively correlated with organic carbons (p<0.05), and negatively correlated with median diameter (p<0.01). The logKoc¡ÐlogKow relationship in rain and dry season was compared with literature. It was found that the logKoc values were higher than those reported in literature, suggesting that soot particles might play an important role in the transport and distribution of PAHs in the study area. In rain season, PAHs in dissolved phase were mainly from pyrogenic origins; while mainly from petrogenic origins in particulate phase. In contrast, in dry season, PAHs in dissolved phase were mainly from petrogenic origins; while mainly from pyrogenic origins in particulate phase. In addition, it was found, relatively, that petrogenic pollution was introduced maily from the northern area of the lagoon. In rain season, total PCB concentrations ranged from 1.1 to 2.7 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 0.42 to 2.1 ng/L and from 0.24 to 1.4 ng/L, respectively. In dry season, total PCB concentrations ranged from 0.54 to 1.3 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 0.20 to 0.74 ng/L and from 0.32 to 0.76 ng/L, respectively. The direction of net fluxes of PAHs in this study are from water to air (net volatilization) in summer. In winter, however, the absorptive PAH fluxes obtained for four to six-ring PAH, such as fluoranthrene, chrysene + triphenylene and benzo[a]anthracene, indicating that PAHs were absorbed into surface waters. According to our results, it was suggested that the results from previous study (Fang, 2007) might underestimate the net fluxes of Pyrene and total fluxes in dry season. The annual fluxes of PAHs estimated in this study were 212 mg/m2 /year and 5.7 kg of PAHs were emitted annually from the harbor lagoon surface waters to the ambient atmosphere.

Langmuir monolayers can be employed as simple model systems to study interactions at surfaces. Such investigations are important to fields ranging from biology to materials science. Herein, several aspects of these films and their associated water structure have been examined with vibrational sum frequency spectroscopy (VSFS). This second order nonlinear optical spectroscopy is particularly well suited for simultaneous investigations of the monolayer and the associated water structure with unprecedented surface specificity. The structures of these systems were altered through the control of experimental parameters including monolayer pressure, subphase temperature, pH and ionic content. Thermodynamic information about structural changes in a fatty amine monolayer's hydrophobic region was obtained by observation of the pressure and temperature dependence of the monolayer's solid to liquid phase transition. Further studies used the coordination of divalent cations to acid monolayers to perturb the water layers nearest to the film which enabled a better understanding of the water related VSFS features from these hydrophilic interfaces. Information from both the monolayer and water structure was then combined in order to examine the role of water in mediating ion-biomaterial interactions, often expressed in terms of the Hofmeister series.

Determining the presence of an analyte of interest, and finding the enantiomeric purity of chiral molecules are challenging tasks. This work in molecular recognition is carried out routinely by many different researchers, including both academic as well as industrial research groups. The following dissertation presents original research directed toward two different areas of interest to the molecular recognition community: enantioselective sensing in solution, and sensing at a defined interfacial environment. This work begins with a review of the non-chromatographic ways that the enantiomeric purity of chiral carboxylic acids is determined, presented in Chapter 1. Carboxylic acids are important functional groups, both for organic synthesis as well as pharmaceutical drug development. Chapter 2 presents efforts that have been made to rapidly assess both the enantiomeric purity and identity of chiral carboxylic acids, utilizing the technique of exciton-coupled circular dichroism (ECCD). A twist is imparted on a complex, and can be correlated with the absolute configuration of the stereocenter. The enantiomeric composition can be rapidly determined. After creating the assay, the focus of the work shifted toward applying this system to new classes of analytes. Chapter 3 covers chemo- and enantioselective differentiation of [mathematical symbol]-amino acids, and continues to discuss the expansion to [mathematical symbol]-homoamino acids. Then a synthetic substrates was tested, and a series of reactions screened to determine if any enantioselectivity had been imparted by a Baeyer-Villiger oxidation. Finally, the enantiomeric composition of a biaryl atropisomer, a compound lacking a stereocenter, was determined. The signal produced from this assay is at a relatively short wavelength, and efforts were undertaken to push this signal to longer wavelength. Chapter 4 is a compendium of the lessons that were learned upon attempting to create a self-assembled sensing system. The final chapter details work that was done in collaboration with Professor Katsuhiko Ariga at the National Institute of Materials Science in Tsukuba, Japan. In this chapter, an indicator displacement assay was carried out for the first time at the air-water interface. This contribution opens the door for sensing to be carried out at defined regions, rather than free in bulk solution. / text