Peristaltic transport of a biofluid in a pipe of elliptic cross section

Peristaltic transport of two fluids occupying the peripheral layer and the core in an elliptic tube is, investigated in elliptic cylindrical co-ordinate system, under long wavelength and low Reynolds number approximations. The effect of peripheral-layer viscosity on the flow rate and the frictional force for a slightly elliptic tube is discussed. The limiting results for the one-fluid model are obtained for different eccentricities of the undisturbed tube cross sections with the same area. As a result of non-uniformity of the peristaltic wave, two different amplitude ratios are defined and the time-averaged flux and mechanical efficiency are studied for different eccentricities. It is observed that the time-averaged flux is not affected significantly by the pressure drop when the eccentricity is large. For the peristaltic waves with same area variation, the pumping seems to improve with the eccentricity.

Lamb wave based identification and parameter estimation of corrosion in metallic plate structure using a circular PWAS array

A circular array of Piezoelectric Wafer Active Sensor (PWAS) has been employed to detect surface damages like corrosion using lamb waves. The array consists of a number of small PWASs of 10 mm diameter and 1 mm thickness. The advantage of a circular array is its compact arrangement and large area of coverage for monitoring with small area of physical access. Growth of corrosion is monitored in a laboratory-scale set-up using the PWAS array and the nature of reflected and transmitted Lamb wave patterns due to corrosion is investigated. The wavelet time-frequency maps of the sensor signals are employed and a damage index is plotted against the damage parameters and varying frequency of the actuation signal (a windowed sine signal). The variation of wavelet coefficient for different growth of corrosion is studied. Wavelet coefficient as function of time gives an insight into the effect of corrosion in time-frequency scale. We present here a method to eliminate the time scale effect which helps in identifying easily the signature of damage in the measured signals. The proposed method becomes useful in determining the approximate location of the corrosion with respect to the location of three neighboring sensors in the circular array. A cumulative damage index is computed for varying damage sizes and the results appear promising.

In-situ impedance spectroscopy of layer-by-layer self-assembly of polyelectrolytes

In-situ impedance spectroscopy of layer-by-layer self-assembly of weak polyelectrolytes is presented. Interdigitated capacitors with active area of 1×1 mm2 and electrode spacing of 5 μm are fabricated and used for this purpose. Measurement results indicate that the impedance decreases with increase in number of polyelectrolyte layers. About 2.5% of relative change in magnitude of impedance at 104.7 KHz is seen for four bi-layers of Poly(Allylamine Hydrochloride) (PAH)/Poly(Acrylic acid) (PAA). An electrical equivalent for polyelectrolyte binding is obtained.

Long-Term Environmental Correlates of Invasion by Lantana camara (Verbenaceae) in a Seasonally Dry Tropical Forest

Invasive species, local plant communities and invaded ecosystems change over space and time. Quantifying this change may lead to a better understanding of the ecology and the effective management of invasive species. We used data on density of the highly invasive shrub Lantana camara (lantana) for the period 1990-2008 from a 50 ha permanent plot in a seasonally dry tropical forest of Mudumalai in southern India. We used a cumulative link mixed-effects regression approach to model the transition of lantana from one qualitative density state to another as a function of biotic factors such as indicators of competition from local species (lantana itself, perennial grasses, invasive Chromolaena odorata, the native shrub Helicteres isora and basal area of native trees) and abiotic factors such as fire frequency, inter-annual variability of rainfall and relative soil moisture. The density of lantana increased substantially during the study period. Lantana density was negatively associated with the density of H. isora, positively associated with basal area of native trees, but not affected by the presence of grasses or other invasive species. In the absence of fire, lantana density increased with increasing rainfall. When fires occurred, transitions to higher densities occurred at low rainfall values. In drier regions, lantana changed from low to high density as rainfall increased while in wetter regions of the plot, lantana persisted in the dense category irrespective of rainfall. Lantana seems to effectively utilize resources distributed in space and time to its advantage, thus outcompeting local species and maintaining a population that is not yet self-limiting. High-risk areas and years could potentially be identified based on inferences from this study for facilitating management of lantana in tropical dry forests.

Time-Based All-Digital Technique for Analog Built-in Self-Test

A scheme for built-in self-test of analog signals with minimal area overhead for measuring on-chip voltages in an all-digital manner is presented. The method is well suited for a distributed architecture, where the routing of analog signals over long paths is minimized. A clock is routed serially to the sampling heads placed at the nodes of analog test voltages. This sampling head present at each test node, which consists of a pair of delay cells and a pair of flip-flops, locally converts the test voltage to a skew between a pair of subsampled signals, thus giving rise to as many subsampled signal pairs as the number of nodes. To measure a certain analog voltage, the corresponding subsampled signal pair is fed to a delay measurement unit to measure the skew between this pair. The concept is validated by designing a test chip in a UMC 130-nm CMOS process. Sub-millivolt accuracy for static signals is demonstrated for a measurement time of a few seconds, and an effective number of bits of 5.29 is demonstrated for low-bandwidth signals in the absence of sample-and-hold circuitry.

Fixed-orientation equilateral triangle matching of point sets

Given a point set P and a class C of geometric objects, G(C)(P) is a geometric graph with vertex set P such that any two vertices p and q are adjacent if and only if there is some C is an element of C containing both p and q but no other points from P. We study G(del)(P) graphs where del is the class of downward equilateral triangles (i.e., equilateral triangles with one of their sides parallel to the x-axis and the corner opposite to this side below that side). For point sets in general position, these graphs have been shown to be equivalent to half-Theta(6) graphs and TD-Delaunay graphs. The main result in our paper is that for point sets P in general position, G(del)(P) always contains a matching of size at least vertical bar P vertical bar-1/3] and this bound is tight. We also give some structural properties of G(star)(P) graphs, where is the class which contains both upward and downward equilateral triangles. We show that for point sets in general position, the block cut point graph of G(star)(P) is simply a path. Through the equivalence of G(star)(P) graphs with Theta(6) graphs, we also derive that any Theta(6) graph can have at most 5n-11 edges, for point sets in general position. (C) 2013 Elsevier B.V. All rights reserved.

Growth of ultrahigh density vertically aligned carbon nanotube forests for interconnects.

We present a general catalyst design to synthesize ultrahigh density, aligned forests of carbon nanotubes by cyclic deposition and annealing of catalyst thin films. This leads to nanotube forests with an area density of at least 10(13) cm(-2), over 1 order of magnitude higher than existing values, and close to the limit of a fully dense forest. The technique consists of cycles of ultrathin metal film deposition, annealing, and immobilization. These ultradense forests are needed to use carbon nanotubes as vias and interconnects in integrated circuits and thermal interface materials. Further density increase to 10(14) cm(-2) by reducing nanotube diameter is possible, and it is also applicable to nanowires.

Photographic analysis of natural and impounded salt marsh in the vicinity of Merritt Island, Florida

Qualitative analyses of available photographs and maps of Merritt Island, Florida provide a large-scale, historical perspective of ecological changes of the marshes in the vicinity. Sites that deserve closer scrutiny can be identified. Secondarily, such an analysis provides a geographical orientation essential for communication not only between newcomers and those familiar with the area, but also among those familiar with the area but who refer to sites by differing methods. Photographs and maps from various sources were examined. Below are listed what we consider to be the most useful subset of these for ecological and geographical assessment of salt marsh impoundments on Merritt Island, Florida. (Document has 25 pages.)

An auto-focusing method for imaging ellipsometry system

An auto-focusing method based on the image brightness gradient sharpness function is presented for imaging ellipsometry system, in which the image plane of the thin-film specimen is not perpendicular to the optical axis. The clear image of a specimen with large area is obtained by moving the imaging sensor in optical axis direction and around its sensitive surface centre successively. The experimental results demonstrate its feasibility.

Identificação de áreas sob maior risco para leishmaniose visceral na cidade de Teresina, Piauí, Brasil

O propósito desta Tese foi detectar e caracterizar áreas sob alto risco para leishmaniose visceral (LV) e descrever os padrões de ocorrência e difusão da doença, entre os anos de 1993 a 1996 e 2001 a 2006, em Teresina, Piauí, por meio de métodos estatísticos para análise de dados espaciais, sistemas de informações geográficas e imagens de sensoriamento remoto. Os resultados deste estudo são apresentados na forma de três manuscritos. O primeiro usou análise de dados espaciais para identificar as áreas com maior risco de LV na área urbana de Teresina entre 2001 e 2006. Os resultados utilizando razão de kernels demonstraram que as regiões periféricas da cidade foram mais fortemente afetadas ao longo do período analisado. A análise com indicadores locais de autocorrelação espacial mostrou que, no início do período de estudo, os agregados de alta incidência de LV localizavam-se principalmente na região sul e nordeste da cidade, mas nos anos seguintes os eles apareceram também na região norte da cidade, sugerindo que o padrão de ocorrência de LV não é estático e a doença pode se espalhar ocasionalmente para outras áreas do município. O segundo estudo teve como objetivo caracterizar e predizer territórios de alto risco para ocorrência da LV em Teresina, com base em indicadores socioeconômicos e dados ambientais, obtidos por sensoriamento remoto. Os resultados da classificação orientada a objeto apontam a expansão da área urbana para a periferia da cidade, onde antes havia maior cobertura de vegetação. O modelo desenvolvido foi capaz de discriminar 15 conjuntos de setores censitário (SC) com diferentes probabilidades de conterem SC com alto risco de ocorrência de LV. O subconjunto com maior probabilidade de conter SC com alto risco de LV (92%) englobou SC com percentual de chefes de família alfabetizados menor que a mediana (≤64,2%), com maior área coberta por vegetação densa, com percentual de até 3 moradores por domicílio acima do terceiro quartil (>31,6%). O modelo apresentou, respectivamente, na amostra de treinamento e validação, sensibilidade de 79% e 54%, especificidade de 74% e 71%, acurácia global de 75% e 67% e área sob a curva ROC de 83% e 66%. O terceiro manuscrito teve como objetivo avaliar a aplicabilidade da estratégia de classificação orientada a objeto na busca de possíveis indicadores de cobertura do solo relacionados com a ocorrência da LV em meio urbano. Os índices de acurácia foram altos em ambas as imagens (>90%). Na correlação da incidência da LV com os indicadores ambientais verificou-se correlações positivas com os indicadores Vegetação densa, Vegetação rasteira e Solo exposto e negativa com os indicadores Água, Urbana densa e Urbana verde, todos estatisticamente significantes. Os resultados desta tese revelam que a ocorrência da LV na periferia de Teresina está intensamente relacionada às condições socioeconômicas inadequadas e transformações ambientais decorrentes do processo de expansão urbana, favorecendo a ocorrência do vetor (Lutzomyia longipalpis) nestas regiões.

Distributed Optimal Control of Cyber-Physical Systems: Controller Synthesis, Architecture Design and System Identification

The centralized paradigm of a single controller and a single plant upon which modern control theory is built is no longer applicable to modern cyber-physical systems of interest, such as the power-grid, software defined networks or automated highways systems, as these are all large-scale and spatially distributed. Both the scale and the distributed nature of these systems has motivated the decentralization of control schemes into local sub-controllers that measure, exchange and act on locally available subsets of the globally available system information. This decentralization of control logic leads to different decision makers acting on asymmetric information sets, introduces the need for coordination between them, and perhaps not surprisingly makes the resulting optimal control problem much harder to solve. In fact, shortly after such questions were posed, it was realized that seemingly simple decentralized optimal control problems are computationally intractable to solve, with the Wistenhausen counterexample being a famous instance of this phenomenon. Spurred on by this perhaps discouraging result, a concerted 40 year effort to identify tractable classes of distributed optimal control problems culminated in the notion of quadratic invariance, which loosely states that if sub-controllers can exchange information with each other at least as quickly as the effect of their control actions propagates through the plant, then the resulting distributed optimal control problem admits a convex formulation.

The identification of quadratic invariance as an appropriate means of "convexifying" distributed optimal control problems led to a renewed enthusiasm in the controller synthesis community, resulting in a rich set of results over the past decade. The contributions of this thesis can be seen as being a part of this broader family of results, with a particular focus on closing the gap between theory and practice by relaxing or removing assumptions made in the traditional distributed optimal control framework. Our contributions are to the foundational theory of distributed optimal control, and fall under three broad categories, namely controller synthesis, architecture design and system identification.

We begin by providing two novel controller synthesis algorithms. The first is a solution to the distributed H-infinity optimal control problem subject to delay constraints, and provides the only known exact characterization of delay-constrained distributed controllers satisfying an H-infinity norm bound. The second is an explicit dynamic programming solution to a two player LQR state-feedback problem with varying delays. Accommodating varying delays represents an important first step in combining distributed optimal control theory with the area of Networked Control Systems that considers lossy channels in the feedback loop. Our next set of results are concerned with controller architecture design. When designing controllers for large-scale systems, the architectural aspects of the controller such as the placement of actuators, sensors, and the communication links between them can no longer be taken as given -- indeed the task of designing this architecture is now as important as the design of the control laws themselves. To address this task, we formulate the Regularization for Design (RFD) framework, which is a unifying computationally tractable approach, based on the model matching framework and atomic norm regularization, for the simultaneous co-design of a structured optimal controller and the architecture needed to implement it. Our final result is a contribution to distributed system identification. Traditional system identification techniques such as subspace identification are not computationally scalable, and destroy rather than leverage any a priori information about the system's interconnection structure. We argue that in the context of system identification, an essential building block of any scalable algorithm is the ability to estimate local dynamics within a large interconnected system. To that end we propose a promising heuristic for identifying the dynamics of a subsystem that is still connected to a large system. We exploit the fact that the transfer function of the local dynamics is low-order, but full-rank, while the transfer function of the global dynamics is high-order, but low-rank, to formulate this separation task as a nuclear norm minimization problem. Finally, we conclude with a brief discussion of future research directions, with a particular emphasis on how to incorporate the results of this thesis, and those of optimal control theory in general, into a broader theory of dynamics, control and optimization in layered architectures.

Variabilité, circulation et chlorophylle dans la région du Dôme d'Angola en février-mars 1971

In February-March 1971 the hydrological conditions off Angola did not display the thermal dome mapped by Mazeika's averages (1967). Cold water cells observed are connected at the surface to a sinuous boundary between low-salinity coastal waters and high-salinity tropical oceanic waters. That boundary coincides rather regularly with an area where trades and SW winds alternate; photosynthesis growths rapidly in a thermoclinal layer that rises until 10 m of the surface but never outcrops. Below a poor and permanent homogeneous surface layer, chlorophyll concentrations show a distribution which is typical of divergence areas. Geostrophical and measured currents show off a transient process in horizontal and vertical movements, however the general curvature of the circulation is propitious to upwelling. Oxygen oversaturations of about 110%, suggest a moderate potential primary production which confirms slowness and alternation of movements. Also, the regular range of the various chemical and biological levels and moderate chlorophyll concentrations suggest an ecosystem where nutrients supply rapidly equilibrate phytoplankton consumption and not at all a 'phytoplankton bloom' area as that which exists in coastal upwelling. Values of Richardson's number show that instability becomes visible at the bottom of the euphotic layer. An evaluation of the vertical motion is inferred by the peculiar distribution and diurnal alternance of the winds shows that 'doming' structures may be sustained by local meteorological events.

Tectônica de emplacement dos diques toleíticos do Arco de Ponta Grossa, entre Curitiba e Paranaguá (PR)

Apesar da grande quantidade de estudos geoquímicos e geocronológicos que têm sido executados no enxame de diques de Ponta Grossa (EDPG), pouco se sabe a respeito da tectônica associada ao seu sin e pós emplacement. O objetivo desse estudo é identificar nos diques possíveis indicadores cinemáticos a fim de compreender essa dinâmica, além de caracterizar a tectônica rúptil Meso-cenozóica associada à área, afetando todas as rochas. A área de estudo está situada no entorno da Baía de Paranaguá, estado do Paraná, onde os diques do EDPG afloram intrudindo domínios pré-cambrianos, compostos por gnaisses, sequências metassedimentares e suítes graníticas pertencentes ao Terreno Paranaguá e uma pequena parte às Microplacas Curitiba e Luís Alves, ambos em contato através de Zonas de cisalhamento (SIGA JR, 1995). Essas rochas possuem direção de foliação marcante NE-SW. Os diques estudados foram divididos em dois grupos com base em estudos petrográficos, com forte predomínio dos básicos toleíticos e subordinadamente, os básicos alcalinos. Alguns diques compostos também foram encontrados, o que demonstra ao menos dois pulsos magmáticos possivelmente associados ao mesmo evento. São diques verticais a subverticais e possuem direção principal NW-SE. Com frequência apresentam fraturamento interno de direção NE-SW, provavelmente associados ao seu processo de resfriamento. Possuem formato tabular, porém não é raro que ocorram irregulares. As principais feições indicativas de movimentação oblíqua na intrusão desses diques são as estruturas de borda em degraus, tocos e zigue-zague, que demonstram em geral uma componente distensional destral de deslocamento. Agregando dados dos demais enxames de diques toleíticos principais, chegou-se a um valor médio de N80E para o tensor σ3 da abertura do Atlântico Sul, coerente com o esperado também para EDPG, visto que foram intrudidos em um ambiente transtensivo (CORREA GOMES, 1996). Falhas e fraturas são observadas cortando tanto as rochas encaixantes quanto os diques, caracterizando uma tectônica posterior à intrusão. As principais famílias de fraturas são N20-30E, N30-40W, N80W e N60-70E, formando zonas preferenciais de erosão no cruzamento entre elas. As falhas podem apresentar plano de falha bem definido com estrias e ressaltos, ocorrendo preenchidas ou não, tendo sido observados preenchimento de sílica e material carbonático. Predomina nas falhas observadas, cinemática sinistral demonstrando mudança no campo de esforços com relação ao emplacement dos diques. O estudo da tectônica rúptil assim como do emplacement dos diques da área vem a contribuir para o melhor entendimento dos processos de abertura do Oceano Atlântico Sul, além de abranger a região emersa do que constitui o embasamento da bacia de Santos, foco de extensivos estudos atualmente, podendo-se inferir que os mesmos processos tenham afetado a região offshore.

Perfil microbiano de infecções endodônticas primárias e sua relação com o tamanho de lesões periradiculares associadas

O presente trabalho tem por objetivo investigar a microbiota de canais radiculares que apresentem lesão perirradicular e relacionar o perfil microbiano detectado com a área/volume destas lesões visualizadas por radiografias periapicais e tomografias computadorizadas tipo cone-beam. Foram selecionados 19 dentes com infecção endodôntica primária. As amostras microbiológicas foram coletadas dos canais com o auxílio de limas tipo Hedströen e cones de papel absorvente estéril. A técnica do Checkerboard DNA-DNA hybridization foi utilizada para detecção de até 79 espécies bacterianas em cada amostra, utilizando sondas de DNA específicas. Os dados microbiológicos foram expressos em percentagem média (prevalência), proporção e nível médio de cada espécie em cada amostra. Os testes t independente e de correlação de Pearson foram usados para correlacionar a contagem das bactérias testadas com os dados clínicos (p≤ 0,05). Foi encontrada uma média de 17 espécies por amostra. E. brachy (70%), S. pneumonia (67,5%), P. oris (67,5%), E. faecium (65%), N. gonorrhoeae (62,5%), K. pneumoniae (62,5%), P. melaninogenica (62,5%), P. nigrescens (62,5%) e P. micra (62,5%) foram as espécies mais prevalentes, e as espécies encontradas em níveis médios mais altos foram P. oris (7,5 x 105), E. brachy (7,3 x 105), E. faecium (7,2 x 105), K. pneumoniae (7,0 x 105), N. gonorrhoeae (6,8 x 105), S. epidermidis (6,5 x 105) e H. pylori (6,5 x 105). Houve correlação positiva entre as lesões periapicais de maior área e contagens significativamente mais altas da carga bacteriana total e de bactérias Gram-negativas (p<0,05). Baseado nos resultados obtidos é possível concluir que a microbiota presente em dentes com periodontite apical primária possui perfil misto e complexo, e que uma maior tamanho de lesão perirradicular pode estar associada a contagem elevada espécie totais e bactérias Gram-negativas.

Análise da diversidade microbiana em infecções endodônticas persistentes

O presente trabalho teve por objetivo investigar a microbiota de canais radiculares relacionadas ao insucesso do tratamento endodôntico, buscando a identificação e a quantificação destes micro-organismos. Foram selecionados 36 dentes com infecção endodôntica persistente. O material obturador foi removido do canal radicular e amostras microbiológicas foram coletadas dos canais com o auxílio de limas tipo Hedströen e cones de papel absorvente estéril. A técnica do Checkerboard DNA-DNA hybridization foi utilizada para detecção de até 79 espécies bacterianas em cada amostra, utilizando sondas de DNA específicas. Os dados microbiológicos foram expressos em percentagem média (prevalência), proporção e nível médio de cada espécie em cada amostra. Os testes t independente e de correlação de Pearson foram usados para correlacionar a contagem das bactérias testadas com os dados clínicos (p≤ 0,05). Foi encontrada uma média de 11 espécies por amostra. E. faecium (36%), S. epidermidis (36%), E. saburreum (28%), P. micra (28%), S. sanguis (28%), C. sputigena (28%), L. buccalis (28%), E. faecalis (28%) e S. warneri (28%) foram as espécies mais prevalentes, e as espécies encontradas em níveis médios mais altos foram E. faecium, D. pneumosintes, S. epidermidis, H. pylori e C. sputigena. T. socranskii (3%), F. periodonticum (3%), C. gingivalis (3%), S. ixodetis (3%) apresentaram prevalências mais baixas. E. faecium e S. epidermidis apresentaram os maiores valores de prevalência, níveis médios e proporção. Não houve correlação entre a microbiota detectada nas amostras com os sinais e sintomas clínicos apresentados pelos pacientes, porém nas lesões periapicais de maior área foi detectada contagem significativamente maior de bacilos e espécies Gram-negativas (p<0,05). Baseado nos resultados obtidos é possível concluir que a microbiota presente em dentes com periodontite apical persistente possui perfil misto e complexo, e que uma maior área de lesão perirradicular pode estar associada a contagem elevada de bacilos e de espécies Gram-negativas.