Fluorometric density gradient ultracentrifugation is used to measure the lipoprotein density profile for cardiovascular disease risk assessment. The work presented establishes the effectiveness of using a single-spin separation as both an analytical tool and a preparative tool, while yielding valuable density information. This research expands on the analytical power of density gradient ultracentrifugation (DGU) by combining novel ethylenediaminetetraacetic acid (EDTA) gradient solutions, a fluorescent probe for analysis, and modern statistical methods for classification of heart disease risk. Sub-classes of lipoproteins are analyzed based on their density from the fluorescent lipoprotein density profile. The application of linear discriminant analysis (LDA) and sliced average variance estimation (SAVE) to the fluorometric DGU data yields a powerful classification tool. This method is capable of determining differences between control and cardiovascular disease patients that do not exhibit the traditional risk factors. The combination of these methods has great potential to serve as analytical tools for researchers in understanding the mechanisms of disease development and as a diagnostic tool for clinicians.

Clusters of galaxies are particularly interesting astrophysical systems, are the largest bound structures in the Universe, and contain fair sample of cosmic ingredients. Studies of cluster abundance as a function of mass and redshift were critical in establishing the standard model of cosmology. This dissertation presents results from X-ray imaging of massive distant (M > 10^14 M; 0:3 < z < 1.2) clusters, found via X-ray emission or Sunyaev-Zeldovich eff ect. This is the world's largest sample of massive galaxy clusters. We explore the radial and azimuthal profi les of the X-ray emitting gas and show that clusters are self-similar objects: their internal structure is largely independent of the cluster's mass or redshift, and the fractions of di fferent types of clusters does not change with redshift. We also present a new statistical technique for measuring a cluster's deviations from a perfect axisymmetric shape, which is especially useful in the case of low photon count observations of distant clusters. / Physics

The bending strength of a commercial 0.82-inch-thick three-layered particleboard was investigated in terms of its bending moment resistance capacity. Experimental results indicated that the bending moment resistance capacity of the particleboard was governed by the tensile and compressive strengths of each of four-layered materials composing of the particleboard. A proposed mechanical model for prediction of the bending moment resistance capacity of the particleboard based on the tensile and compressive strengths of each of three-layered materials was validated experimentally. The developed mechanical model can be used to explain four different variations in terms of different combinations of layer strength properties commonly occurred in real manufacturing environment due to process variations. The optimal combination in terms of each layer tensile and compressive strength property can be obtained.

Surface-generalized ambient noise in a shallow ocean waveguide with a sediment layer possessing a specific class of density and sound speed distributions capable of describing a realistic seabed environment is considered in this analysis. This class of non-uniform sediment layer has the density and sound speed distributions varying with respect to depth as a genearlized-exponential and an inverse-square function, respectively. The study invokes a formulation developed by Kuperman and Ingenito for surface noise generation, in conjunction with the analytical solutions for the Helmholtz equation corresponding to the sediment layer, to arrive at an analytical expression convenient for numerical implementation. The intensity and spatial correlation of the noise sound field are analyzed with respect to the variations of the system parameters, including frequency, sediment layer thickness, sound speed gradient, with emphasis on the effects of sediment properties on the ambient noise field. The results have demonstrated that the intensity of the noise field is relatively sensitive to the variations of the paramters, while the spatial correlation is not, suggesting that the energy distribution, rather than the spatial structure, of the noise field is susceptible to the environmental variation.

Made available in DSpace on 2014-12-17T14:08:35Z (GMT). No. of bitstreams: 1 KleberCOCpdf.pdf: 2178209 bytes, checksum: 588b533d30c060af9cf941e7001d3372 (MD5) Previous issue date: 2009-04-22 / In recent years, the DFA introduced by Peng, was established as an important tool capable of detecting long-range autocorrelation in time series with non-stationary. This technique has been successfully applied to various areas such as: Econophysics, Biophysics, Medicine, Physics and Climatology. In this study, we used the DFA technique to obtain the Hurst exponent (H) of the profile of electric density profile (RHOB) of 53 wells resulting from the Field School of Namorados. In this work we want to know if we can or not use H to spatially characterize the spatial data field. Two cases arise: In the first a set of H reflects the local geology, with wells that are geographically closer showing similar H, and then one can use H in geostatistical procedures. In the second case each well has its proper H and the information of the well are uncorrelated, the profiles show only random fluctuations in H that do not show any spatial structure. Cluster analysis is a method widely used in carrying out statistical analysis. In this work we use the non-hierarchy method of k-means. In order to verify whether a set of data generated by the k-means method shows spatial patterns, we create the parameter ? (index of neighborhood). High ? shows more aggregated data, low ? indicates dispersed or data without spatial correlation. With help of this index and the method of Monte Carlo. Using ? index we verify that random cluster data shows a distribution of ? that is lower than actual cluster ?. Thus we conclude that the data of H obtained in 53 wells are grouped and can be used to characterize space patterns. The analysis of curves level confirmed the results of the k-means / Nos ?ltimos anos, o DFA introduzido por Peng, foi estabelecido como uma importante ferramenta capaz de detectar autocorrela??o de longo alcance em s?ries temporais com n?o-estacionaridade. Esta t?cnica vem sendo aplicado com sucesso a diversas ?reas tais como: Econofis?ca, Biof?sica, Medicina, F?sica e Climatologia. No presente trabalho, utilizamos a t?cnica do DFA para obter o expoente de Hurst (H) do perfil el?trico de densidade (RHOB) de 53 po?os provindos do Campo Escola de Namorado. Neste trabalho queremos saber se podemos, ou n?o, utilizar este expoente para caracterizar espacialmente o campo. Duas hip?teses surgem: Na primeira o conjunto dos H reflete a geologia local, po?os com mesmo H se encontram pertos, e ent?o se pode pensar em utilizar H em procedimentos geoestat?sticos espaciais. Na segunda hip?tese cada po?o tem seu H, a informa??o dos H de cada po?o est? descorrelacionada e o conjunto dos perfis mostra apenas flutua??es aleat?rias em H que n?o revelam qualquer estrutura espacial. A an?lise de agrupamentos ? um m?todo bastante utilizado na realiza??o de an?lises estat?sticas. Nesta disserta??o utilizamos o m?todo de agrupamento n?o hier?rquico chamado m?todo do k-m?dia. Com o objetivo de verificar se um conjunto de dados gerados pelo m?todo do k-m?dia, ou de forma aleat?ria, forma padr?es espaciais, criamos o par?metro ? (?ndice de vizinhan?a). Altos ? implicam em dados mais agregados, baixos ? em dados dispersos ou sem correla??o espacial. Com aux?lio deste ?ndice e do m?todo de Monte Carlo verificamos que os dados agrupados aleatoriamente apresentam uma distribui??o mais baixa de ? do que os obtidos dos dados concretos e agrupados pelo k-m?dia. Desta forma conclu?mos que os dados de H obtidos nos 53 po?os est?o agrupados e podem ser usados na caracteriza??o espacial de campos. A an?lise de curvas de n?vel confirmou o resultado do k-m?dia

This study explores the performance of porous Paptic paper materials composed of a mixture of softwood and lyocell fibers. The investigation involves laboratory experiments and numerical simulations to analyse the impact of various parameters on the paper's characteristics. Tensile and hygroexpansion tests were conducted on sheets with different binder quantities and drying methods. VTT aided in the analysis of mechanical properties using tomography images. The objective was to determine the optimal binder content, to understand the behaviour of the paper under different drying conditions and to optimise the pulp mixture through numerical simulations. Experimental tests involved producing paper sheets with varying binder amounts and different drying methods. Tensile tests were conducted to assess the elastic stiffness, strength, and strain at break. Constrained dried and freely dried papers were compared to evaluate the influence of drying conditions. Hygroexpansion tests were performed to examine the water storage behaviour of papers with added binders. Tomography measurements provided the density profile, which was replicated in the numerical sheets. A micro-mechanical model was employed for numerical simulations, representing each fiber as a beam. The model was calibrated using stress-strain data from VTT's tensile testing of the paper with the highest binder content. The influence of altering the amount and length of lyocell fibers was examined to optimise the pulp. From the tensile tests, an optimal binder content was identified that yielded the highest elastic stiffness while considering the density increase caused by binders. Further additions of binders did not enhance elastic stiffness. However, no optimal value was found for strength and strain at break, as both parameters continued to increase with additional binders. Tensile tests comparing constrained dried and freely dried papers showed similar behaviour, suggesting inadequate constraint in the former. Hygroexpansion tests confirmed the similarities between the two drying methods and revealed that papers with added binders stored less water at a given humidity. Additionally, the drying-moistening cycling exhibited an unusual behaviour not observed in conventional paper, with irreversible expansion occurring during the first drying cycle. Numerical simulations using a micro-mechanical model demonstrated that higher amounts of lyocell fibers improved performance, increasing strength and strain at break. However, varying fiber length did not yield significant improvements in these parameters, although stiffness showed a slight increase. While the literature suggests that the addition of long lyocell fibers decreases paper strength, this study found that when maintaining constant bulk, strength increased under the assumption that the bonding strength was unaffected by lyocell fibers. Furthermore, numerical simulations indicated that an even density profile throughout the paper thickness resulted in higher strength and strain at break. The tomography data revealed that the density profile is affected by the binder quantity. With the addition of binders, the thickness decreased even though the grammage increased. The density is high on the top and bottom surface of the papers which contain more binders while the density is lower in the middle. This difference in density is more pronounced with higher amounts of binders. / Denna studie undersöker prestandan hos porösa pappersmaterial från Paptic som består av en blandning av barrträd och lyocell-fibrer. Undersökningen innefattar laboratorieexperiment och numeriska simuleringar för att analysera effekten av olika parametrar på papperets egenskaper. Drag- och hygroexpansionstester utfördes på ark med olika mängder bindemedel och torkningsmetoder. VTT hjälpte till med analysen av mekaniska egenskaper genom tomografibilder. Målet var att bestämma optimalt innehåll av bindemedel, att förstå papperets beteende under olika torkningsförhållanden och att optimera pappersmassan genom numeriska simuleringar.  De experimentella testerna innefattade framställning av pappersark med varierande mängder bindemedel och olika torkningsmetoder. Dragtester utfördes för att bedöma elastisk styvhet, styrka och töjning vid brott. Inspännt samt fritt torkade papper jämfördes för att utvärdera inflytandet av torkningsförhållanden. Hygroexpansionstester utfördes för att undersöka vattenlagringsbeteendet hos papper med tillsatt bindemedel. Tomografimätningar gav papprens densitetsprofilen, som återskapades i de numeriska arken. En mikromekanisk modell användes för de numeriska simuleringarna, där varje fiber representeras som en balk. Modellen kalibrerades med hjälp av spännings-töjnings-data från VTT:s dragprovning av papperet med högst mängd bindemedel. Inflytandet av att ändra mängden och längden på lyocell-fibrer undersöktes för att optimera pappersmassan.  Från dragtesterna identifierades en optimal mängd bindemedel som gav högst elastisk styvhet när den densitetsökning som orsakas av bindemedel har tagits till hänsyn. Ytterligare tillsatser av bindemedel förbättrade inte den elastiska styvheten. Dock hittades ingen optimal värde för styrka och brottsträckning, eftersom båda parametrarna fortsatte öka med ytterligare bindemedel. Dragtester som jämförde inspännt och fritt torkat papper visade liknande beteende, vilket tyder på otillräcklig begränsning i det förstnämnda fallet. Hygroexpansionstester bekräftade likheterna mellan de två torkningsmetoderna och avslöjade att papper med tillsatt bindemedel lagrade mindre vatten vid en given luftfuktighet. Dessutom uppvisade torknings-fuktnings-cykeln ett ovanligt beteende som inte observerats i konventionellt papper, där irreversibel expansion inträffade under den första torkningscykeln. Numeriska simuleringar med en mikromekanisk modell visade att högre mängder lyocell-fibrer förbättrade prestandan genom att öka styrka och töjning vid brott. Ändringar i fibrernas längd gav dock inte märkvärda förbättringar i dessa parametrar, även om styvheten visade en liten ökning. Medan litteraturen föreslår att tillsatsen av långa lyocell-fibrer minskar papperets styrka, fann denna studie att när densiteten hålls konstant ökar styrkan under antagandet att bindestyrkan inte påverkas av lyocell-fibrer. Dessutom indikerade de numeriska simuleringarna att en jämn densitetsprofil genom papperets tjocklek resulterade i högre styrka och töjning vid brott. Tomografidata visade att densitetsprofilen påverkas av mängden bindemedel. När mängden bindemedel ökade, minskade tjockleken trots att ytvikten ökade. Densiteten är hög på papperets över- och undersida, medan densiteten är lägre i mitten. Skillnaden i densitet är mer uttalad med högre mängder bindemedel.

The content of this dissertation is divided into two main topics: 1) nonlinear profile monitoring and 2) an improved approximate distribution for the T² statistic based on the successive differences covariance matrix estimator. Part 1: Nonlinear Profile Monitoring In an increasing number of cases the quality of a product or process cannot adequately be represented by the distribution of a univariate quality variable or the multivariate distribution of a vector of quality variables. Rather, a series of measurements are taken across some continuum, such as time or space, to create a profile. The profile determines the product quality at that sampling period. We propose Phase I methods to analyze profiles in a baseline dataset where the profiles can be modeled through either a parametric nonlinear regression function or a nonparametric regression function. We illustrate our methods using data from Walker and Wright (2002) and from dose-response data from DuPont Crop Protection. Part 2: Approximate Distribution of T² Although the T² statistic based on the successive differences estimator has been shown to be effective in detecting a shift in the mean vector (Sullivan and Woodall (1996) and Vargas (2003)), the exact distribution of this statistic is unknown. An accurate upper control limit (UCL) for the T² chart based on this statistic depends on knowing its distribution. Two approximate distributions have been proposed in the literature. We demonstrate the inadequacy of these two approximations and derive useful properties of this statistic. We give an improved approximate distribution and recommendations for its use. / Ph. D.

There is a need for multifunctional polymer-particle complexes for use in biomedical applications such as for drug delivery or as MRI contrast agents where composition and stability are essential for the complexes to function. This work outlines a general methodology for rationally designing complexes stabilized with polymer brush layers using adapted star polymer models for brush extension and pair potential. Block copolymer micelles were first utilized for experimental validation by using the brush extension model to predict the size and the interaction model to predict the second virial coefficient, A2. Subsequently, the models were used to predict the size and colloidal stability of magnetite-polymer complexes using the modified Deryaguin-Verwey-Landau-Overbeek theory. Novel hydrophilic triblock copolymers comprised of poly(ethylene oxide) tailblocks and a carboxylic acid containing polyurethane center block were examined by static and dynamic light scattering (SLS and DLS), small angle neutron scattering (SANS), and densiometry. Under conditions when the charge is suppressed such as at low pH and/or high ionic strength, the polymer chains self-assemble into micelles, whereas unimers alone are present under conditions where charge effects are important, such as high pH and low ionic strength. A model for effective interaction between star polymers was used to obtain an expression for the second virial coefficient (A2) for micelles in solution. The values of A2 obtained using this method were compared with experimentally determined values for star polymers and micelles. In doing so, not only was a new means of calculating A2 a priori introduced, but the applicability of star polymer expressions to micellar systems was established. Through the analogy of micelles to sterically stabilized nanoparticles, this model was applied to water-soluble block copolymers adsorbed on magnetite nanoparticles for the purpose of tailoring a steric stabilizing brush layer. The sizes of the magnetite-polymer complexes were predicted using the star polymer model employed for the micelle study with an added layer to account for the anchor block. Colloidal stability was predicted from extended DLVO theory using the pair interaction. This work will lead to a better understanding of how to design ion-containing block copolymers for steric stabilization of metal oxide nanoparticles. / Ph. D.

No description available.

Neste trabalho estudamos os type-dependent stochastic spin models propostos por Fernández et al., os que chamaremos de modelos de spins estocástico dependentes de tipo, e que foram usados para modelar redes de sinalização biológica. A modelagem original descreve a evolução macroscópica de um modelo de spin-flip de tamanho finito com k tipos de spins, possuindo um número arbitrário de estados internos, que interagem através de uma dinâmica estocástica não reversível. No limite termodinânico foi provado que, em um intervalo de tempo finito as trajetórias convergem quase certamente para uma trajetória determinística, dada por uma equação diferencial de primeira ordem. Os comportamentos destes sistemas dinâmicos podem incluir bifurcações, relacionadas às transições de fase do modelo. O nosso objetivo principal foi de estender os modelos de spins com dinâmica de Glauber utiliza- dos pelos autores, permitindo trocas múltiplas dos spins. No contexto biológico tentamos incluir situações nas quais moléculas de tipos diferentes trocam simultaneamente os seus estados internos. Utilizando diversas técnicas, como as de grandes desvíos e acoplamento, tem sido possível demonstrar a convergência para o sistema dinâmico associado. / We study type-dependent stochastic spin models proposed by Fernández et al., which were used to model biological signaling networks. The original modeling setup describes the macroscopic evolution of a finite-size spin-flip model with k types of spins with arbitrary number of internal states interacting through a non-reversible stochastic dynamics. In the thermodynamic limit it was proved that, within arbitrary finite time-intervals, the path converges almost surely to a deterministic trajectory determined by a first-order (non-linear) differential equation. The behavior of the associated dynamical system may include bifurcations, associated to phase transitions in the statistical mechanical setting. Our aim is to extend the spin model with Glauber dynamics, to allow multiple spin-flips. In the biological context we included situations in which molecules of different types simultaneously change their internal states. Using several methods, such as large deviations and coupling, we prove the convergence theorem.