Thesis (Honors)--College of William and Mary, 2009. / Includes bibliographical references (leaves 66-69). Also available via the World Wide Web.

In this work, a microplasma-based ionization source for ambient mass spectrometry (AMS) has been developed. Optical emission spectroscopy, optical microscopy, and electrical measurements have been used to characterize the discharge. The discharge was used in a direct exposure mode in AMS experiments, and was found to behave as a small Penning ionization source capable of ionizing a range of biomolecules via proton transfer. In order to broaden the effectiveness of the microplasma ionization source, admixtures of hydrogen in neon gas were used to produce vacuum ultraviolet (VUV) light. The 121.6 nm Lyman-? (10.23 eV) photons produced are effective soft (non-destructive), single-photon ionization sources. Since this photon energy exceeds the ionization potential of many biomolecules, this source is useful for analysis of a wide range of organic samples. The microplasma source, in both VUV-generating and direct-exposure modes, is proposed as a method by which to study the damage effects on biomolecules, and preliminary results are presented. Finally, a collaborative work investigating the role of ionizing radiation in the DNA damage process is presented. Using a synchrotron radiation source, the photolysis of DNA monolayers on gold substrates in a vacuum environment were studied by X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) experiments.

No description available.

La rencontre de l’intelligence ambiante et de la robotique d’assistance a donné naissance à ce que nous avons appelé robotique ambiante d’assistance car destinée à assister une personne en perte d’autonomie. Elle s’appuie sur l’existence de réseaux d’objets communicants présents dans l’environnement de la personne pour décliner un ensemble de services et de téléservices destinés à faciliter la vie quotidienne de cette personne et de son entourage. Un, voir plusieurs robots peuvent être présents dans cet environnement. Une communauté scientifique récente s’est construite autour de la robotique ubiquitaire. Tandis que les robots des générations précédentes ont été conçus pour réaliser des tâches spécifiques et construits en tant qu’unité indépendante, la nouvelle génération vise l’ubiquité. L’autonomie du robot est obtenue par une interaction étroite entre le robot et l’environnement ambiant communicant. Dans le contexte de l’intelligence ambiante, les objets communicants de l’environnement peuvent jouer un rôle "facilitateur" en aidant le robot à se localiser, naviguer, rechercher un objet. Inversement, le robot peut être vu comme un objet communicant qui est mis à contribution par des services autres que l’assistance à la personne en perte d’autonomie. Ainsi le premier objectif de cette thèse est de proposer une architecture informatique permettant la coopération entre le robot et les objets communicants présents dans l’environnement tels que les capteurs ou les actionneurs. Le deuxième objectif est de proposer une méthode de localisation par coopération robot-environnement communicant. Notre ambition est de localiser avec certitude le robot dans une zone de l’habitat. / The meeting of ambient intelligence and assistive robotics gave birth to ambient assistive robotics which aims at assisting a person in loss of autonomy. It relies on the existence network of communicating objects present in the environment of the person. The objective is to propose a set of services and teleservices for facilitating the person's daily life. One or more robots can be present in this environment. Previous generation of robots have been designed to perform tasks specific and built as an independent unit, while the new generation of robots tries to take advantage of ubiquity. In this framework, the robot autonomy is obtained by a close interaction between the robot and the ambient environment. Up to recent years the robot moved in a rather hostile environment which did not facilitate its task. In the context of ambient intelligence, the communicating objects of ambient environment can play a "facilitator" role in helping the assistive robot for locating itself, searching for a person … Conversely, the robot can be seen as a communicating object which is used by services to the person in loss of autonomy. The first objective of this thesis is to propose an architecture for cooperation between the robot and communicating objects and the second objective is to propose a localization method by cooperation of ambient environment and a mobile robot.

Of all the forms of radiation known, sound travels through the sea the best, therefore it is widely used in underwater detection and signal transmission. However, the ambient noise in the ocean will affect the quality of these applications, so that understanding of ambient noise is important for improving acoustic capability. Previous literatures show that ambient noise at deep water should decrease with depth, but would it be the same in the shallow? Most studies of ambient noise were made at deep water in the past, the reason is that great depth variation of ambient noise is easily observed. The ASIAEX 2001 South China Sea experiment is on the continental shelf-break, so the depth effect of ambient noise in shallow water can be explored. A typhoon shall affect experimental zone during May 10-14, 2001. From the results of this study, afternoon effect shall affect distribution of temperature and ambient noise under water depth. The other, a typhoon can not only affect seriously ambient noise, but also intercept the shine and variation of sea temperature, and reduce afternoon effect. Another, ambient noise has insignificant change with depth, however it¡¦s is much affected by the variation of temperature, frequency, and occurrence of internal wave.

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Med detta projekt titta närmare på hur man kan skapa en belysningsarmatur som skapar ett harmoniskt ljus till offentlig miljö inomhus, med en intressant design på armaturen. En belysningsarmatur som ger en ljusbild av ambient ljus för de som besöker lokalen. Resultatet ska vara en golvlampa för det offentliga rummet som ger ett diffust ljus som komplettera det allmänljuset man redan har i rummet. En golvlampa som gör det möjligt att flytta ljusbelysningen dit i rummet där man behöver den.

En aquesta tesi s’avalua un sistema híbrid de jet impactant/ microcanals, a escala micromètrica. S’inclou el procediment de dimensionament i la construcció del dissipador mitjançant el procés de microfabricació. Amb proves experimentals que permeten el càlcul de paràmetres com el coeficient de resistència tèrmica i la desviació estàndard de la temperatura, s’avalua el comportament del sistema en comparació amb d’altres de similars a escala mil•limètrica. Paral•lelament es desenvolupa i valida un model numèric per simular el comportament del dispositiu. El model permet analitzar l’efecte de la velocitat del fluid refrigerant així com l’impacte del material d’interfície tèrmica (TIM). També s’estudia l’efecte de la geometria del jet utilitzant el quocient entre l’amplitud de l’entrada del fluid i la distància entre aquesta i el punt d’impacte (z/b). La resistència tèrmica, la uniformitat de temperatura i les pèrdues de pressió s’analitzen en funció d’aquest paràmetre z/b. Finalment, per estudiar l’adaptació del dissipador a fluxos de calor bidimensionals s’avalua un disseny de matriu d’agulles, comparant-lo amb el dissipador de microcanals. / En esta tesis se evalúa un sistema híbrido de jet impactante/microcanales, a escala micrométrica. Se incluye el procedimiento de dimensionamiento y la construcción del disipador mediante el proceso de microfabricación. Con pruebas experimentales que permiten el cálculo de parámetros como el coeficiente de resistencia térmica y la desviación estándar de la temperatura se evalúa el comportamiento del sistema en comparación con otros de similares a escala milimétrica. Paralelamente se desarrolla y valida un modelo numérico para simular el comportamiento del dispositivo. El modelo permite analizar el efecto de la velocidad del fluido refrigerante así como el impacto del material de interfaz térmica (TIM). También se estudia el efecto de la geometría del jet utilizando el cociente entre la amplitud de la entrada del fluido y la distancia entre ésta y el punto de impacto (z/b). La resistencia térmica, la uniformidad de temperatura y las pérdidas de presión se analizan en función de este parámetro z/b. Finalmente, para estudiar la adaptación del disipador a flujos de calor bidimensionales se evalúa un diseño de matriz de agujas, comparándolo con el disipador de microcanales. / This thesis evaluates a hybrid microchannels/jet impingement system, in a micrometer scale. The work includes the dimensioning process and the heat sink development using a microfabrication process. With the experimental tests that allow to calculate parameters like the thermal resistance coefficient and the temperature standard deviation, the system behaviour is evaluated in comparison to similar ones in a millimeter scale. In parallel a numeric model is developed and validated in order to simulate the behaviour of the device. The model makes possible to analyse the effect of the cooling fluid velocity as well as the impact of the thermal interface material (TIM). In addition the effect of the jet geometry is studied using the nozzle to plate spacing (z/b) . The thermal resistance, temperature uniformity and pressure drop are analysed in function of this z/b parameter. Finally, a pin fins design is evaluated comparing it with the microchannels heat sink, in order to study the adjustment of the heat sink to bidimensional heat fluxes.

Humanity is currently using more than 200000 synthetic organic compounds in many industrial, agricultural and domestic applications. Many of these chemicals reach the environment and have a harmful effect on ecosystems and humans. Among them, the group of persistent organic pollutants (POPs) comprises several families of compounds that have physical and chemical properties that give them the ability to be distributed and impact globally (semivolatility, high persistence and bioaccumulation capacity due to their hydrophobicity). In the present thesis, the coupling of atmospheric transport and biogeochemical cycles in the Arctic and Southern Ocean has been studied for Hexachlorocyclohexanes (HCHs), Hexachlorobenzene (HCB) and Polychlorinated Biphenyls (PCBs). Three oceanographic cruises were conducted, one in the North Atlantic and the Arctic Ocean (2007) and two in the Southern Ocean surrounding the Antarctic Peninsula (2008 and 2009). During these campaigns, air (gas and particulate), water (dissolved and particulate) and biota (phytoplankton) were sampled simultaneously allowing to report a complete picture of POPs cycling in polar areas. In the case of the Southern Ocean, the largest data set available for PCBs, HCH and HCB has been generated. The atmospheric and seawater concentrations were low, among the lowest reported for the Polar Oceans, and in the case of the Southern Ocean there is a clear historical trend of decreasing concentrations, consistent with reduced emissions in source regions. Long range atmospheric transport was identified as the main POPs input to polar ecosystems agreeing with previous works. However, it has been found that secondary local sources from soil and snow influences strongly the atmospheric concentrations overland in the Antarctic region, and over the adjacent Southern ocean in the case of HCHs. Atmospheric residence times calculated from the measurements were in agreement with the prediction from environmental fate models. The atmospheric residence times were longer for the less hydrophobic PCBs and shorter for the more hydrophobic, consistent with the role of the biological pump sequestering atmospheric PCBs. Once POPs reach the Polar regions the main route of entry of these compounds to surface waters is by atmospheric deposition, mainly by diffusive exchange between the gas and dissolved phase with minor contributions from dry deposition of aerosol bound POPs. Estimated bioconcentration factors revealed that concentration of POPs in phytoplankton were correlated with the chemical hydrophobicity, but some discrepancies with model predictions were observed. The biological and degradative pumps are identified as the two main processes that control the fate and occurrence of POPs in the surface water column, and also are able to modulate the atmospheric transport of POPs to remote areas. POPs such HCHs are prone to be efficiently degraded by bacterial communities in surface waters, depleting the seawater concentrations and increasing the diffusive air-water exchange to the Arctic and Southern Ocean. Conversely, the biological pump decreases the dissolved phase concentrations of the more hydrophobic PCB congeners increasing the air to water fugacity gradients and enhancing the diffusive air-water exchange fluxes. This is the first time that the influence of the biological pump on POP cycling is demonstrated for Oceanic waters. Finally, HCB was close to air-water equilibrium showing that neither the biological and degradative pumps are efficient sequestration processes for the highly persistent and mid-hydrophobic compounds. Overall, the results show clearly that biogeochemical processes occurring in the water column affect the atmospheric deposition and long range transport of POPs to remote regions.The magnitude of these processes may show a clear seasonality and are suitable to be perturbed under the current scenario of climate change. / En la actualidad se usan en aplicaciones domésticas más de 200.000 compuestos orgánicos sintéticos. Muchos de estos compuestos químicos que se liberan al medio ambiente son nocivos para el medio ambiente y los humanos. Entre estos compuestos se encuentran los contaminantes orgánicos persistentes (COPs) que comprenden una serie de familias de compuestos que comparten una serie de características físico-químicas que les permiten estar distribuidos globalmente (semivolatilidad, elevada persistencia y capacidad de bioacumulacion por sus características hidrofóbicas). En la presente tesis doctoral se ha estudiado en profundidad el acoplamiento entre el transporte atmosférico y los ciclos biogeoquímicos Hexaclorociclohexanos (HCHs), Hexaclorobenceno (HCB) y Bifenilos Policlorados (PCBs) en los Océanos Polar Ártico y Polar Antártico. Durante esta tesis se han realizado tres campañas oceanográficas, una al Atlántico Norte y al Océano Polar Ártico (2007), y dos en el Océano Polar Antártico y en aguas circundantes a la Peninsula Antártica (2008 y 2009). Durante estas tres campañas oceanográficas se han tomado muestras de aire (gas y particulado), agua (disuelto y particulado) y biota (fitoplankton) de forma simultánea lo que permitió tener una amplio conocimiento de el ciclo de los COPs en zonas polares. En el caso de el Océano Polar Antártico y en aguas circundantes a la Peninsula Antártica se ha generado la mayor cantidad de datos en un mismo trabajo, incluso se han generado datos que hasta ahora no se habían publicado como las concentraciones de fitoplankton. La concentraciones medidas en el la atmósgera y aguas superficiales fueron bajas, siendo en algunos casos las concentraciones más bajas jamás encontradas en el océano polares, en el caso de el Océano Polar Antártico se ha encontrado una significativa tendencia histórica de concentraciones decrecientos lo cual es consistente con la reducción de emisiones de COPs en origen. El transporte atmosférico a larga distancia ha sido identificado como la vía de entrada principal de entrada de los COPs a sistemas polares. Sin embargo, se ha encontrado que hay fuentes secundarias provenientes de el suelo y la nieve con una clara influencia sobre las concentraciones atmosféricas en zonas de el continente Antártico y aguas costeras adyacentes en el caso de los HCHs. Los tiempos de residencia atmosférica calculados están en los mismos rangos con los modelos predictivos. Los tiempos de residencia atmosférica fieron más largos para los compuestos menos hidrofóbicos y más cortos para los más hidrófobicos lo cual es consistente con la bomba biológica. Una vez estos compuestos alcanzan las regions polares la principal ruta de entrada de estos compuestos al agua superficial es por deposición atmosférica, principalmente por intercambio difusivo entre la fase gas y la fase disuelta, se ha comprobado que la contribución de la deposición seca es significativamente menor. Los factores de bioconcentración revelaron que la concentración de COPs en el fitoplankton se correlacionaba con la hidrofobicidad química, pero se encontraron discrepancias con los modelos predictivos. Las bombas biológica y degradative han sido identificadas como los dos procesos principals que controlan el destino y ocurrencia de COPs en la columna de agua superficial e incluso son capaces de modular el transporte atmosférico de COPs a areas remotes. COPs como los HCHs son eficientemente degradados por las comunidades bacterianas de aguas superficiales disminuyendo su concentraciéon aumentando los flujos difusivos de deposición entre la fase gas y la superficie disuelta en el Océano Polar Antártico y en aguas circundantes a la Peninsula Antártica. Por otro lado, la bomba biológica disminuye las concentraciones de el disuelto de los COPs más hidrofóbicos aumentando el gradiente de fugacidades y favoreciendo la deposición por intercambio difusivo aire-agua. La presente tesis es la primera que ha demostrado la influencia de la bomba biológica influye de forma significativa el ciclo de los COPs.El HCB se ha encontrado en equilibrio en ambas zonas de estudio y no se ha demostrado que hubiera influencia de la bomba biológica o de procesos degradativos en aguas superficiales. Como conclusion final se ha demostrado a través de los resultados que los procesos biogeoquímicos en la columna de agua afectan a la deposición atmosférica y el transporte a larga distancia de COPs a regiones remotas. La magnitud de estos procesos muestra una clara estacionalidad que puede ser perturbada en un actual escenario de cambio climático.

A new era of high-throughput mass spectrometry emerged with the nearly simultaneous introduction of two ambient ionization techniques: desorption electrospray ionization (DESI) and direct analysis in real time (DART). The ability to integrate near instantaneous sample analysis with the specificity of mass spectrometry opened up a broad range of applications. While some of these involve the direct analysis of bulk materials, many others require the collection and deposition of samples onto suitable substrates. This dissertation details the development of a new mode of operation for DESI. Instead of depositing a sample onto a continuous surface, the sample is either collected by or deposited onto a mesh substrate. Analytes either adsorb to the mesh strands or become suspended within the confines of the mesh in macroscale droplets. The samples are then analyzed by scrolling the mesh orthogonally into the path of an electrospray plume positioned coaxial to the inlet capillary of the mass spectrometer, thereby resulting in the transmission of the ionizing plume directly through the material. The transmission mode results in desorption and ionization typical of DESI, but with the added benefits of a simpler experimental geometry and the convenient analysis of both dry (i.e., following evaporation of the deposition solvent) and wet (i.e., solvated) samples. The simplification of the experimental arrangement increases method robustness and reproducibility, while the inclusion of a mesh substrate introduces new possibilities for sample collection and introduction, due to the intricate chemistry between the mesh material, analytes, and deposition/electrospray solvent system. However, the most important benefit lies in the development of surface-enhanced TM-DESI, whereby mesh substrates are derivatized to specifically capture and concentrate targeted analytes directly from solution. Following removal of matrix interferences by sample rinsing and subsequent cleavage of a photolabile linker, the mesh is analyzed directly by TM-DESI-MS. The technique has the potential to overcome interferences that have typically required chromatographic separations using LC-MS or have been insurmountable using ambient ionization methods. The impact of the surface-enhanced method could be tremendous as it may ultimately unite the competing metrics of analytical speed and specificity for ambient ionization mass spectrometry. / text