Orientador: Edson Denis Leonel / Resumo: Nesse trabalho, utilizaremos um autômato celular para investigar o problema de roubos e furtos residenciais. A partir de regras e critérios pré-estabelecidos, definimos o comportamento da difusão da criminalidade em uma cidade como função do tempo e dos seus parâmetros de controle. Utilizando um tratamento estatístico da criminalidade, nossos resultados indicam uma possível transição entre fase endêmica, onde o crime existe porém em baixa ocorrência, e uma fase epidêmica, onde o crime é desenfreado. / Abstract: In this work, we will use a cellular automata to investigate the problem of residential robberies. Starting from a set of rules and criteria, the diffusion of the crime is investigated either as a function of time as well function of the control parameters. Using a statistical treatment our results indicate a possible phase transition between endemic, where crime exists but in low occurrence, and epidemic where crime is rampant. / Mestre

Seminario de Título entregado a la Universidad de Chile en cumplimiento parcial de los requisitos para optar al Título de Químico Ambiental / Iron (Fe) is a transition metal usually found in potable water at low concentrations, whose concentration limit is 0.3 mg / L according to NCh 409, and due to its common use mainly in pipelines and industries, it must be constantly monitored, in order to keep its concentration under the limits and guarantee the welfare of people. The aim of this work is to promote an easy method to identify and extract Fe from potable and natural waters through solid phase extraction. This was done both for acid and basic mediums. 0.4 mL of sulfosalicylic acid (SSA) at 2.5% w/v was used as a ligand, adding 3 mL of a monochloroacetic acid buffer for the samples in acid medium and 3 mL of concentrated NH3 (12,66 M) for samples in basic medium and form a complex, either Fe(III)-SSA or Fetotal-SSA, in 100 mL total solution. Then, an anion exchange solid resin was added, called AG 2-x8 from BIORAD, in order to preconcentrate the complex. Previous studies were conducted without the addition of resin to observe the formation of the complex and study its characteristics. The quantification limits were 0.56 ppm and 0.28 ppm, which are very high or too close to the concentration limit of Fe allowed in potable water, that is, 0.3 ppm (NCh 409). Solid phase studies were carried out in order to decrease the quantification limits of the method. Then the chemical variables involved in obtaining the complex were optimized, such as the amount of SSA, anionic resin, buffer and total volume. Thus obtaining the adequate amounts for each analyte, mentioned above. The extraction of the Fe-ASS complex was possible for both media. However, in a basic medium it requires much higher Fe concentrations for its formation and presented a constant turbidity in the form of a colloidal compound of gray tone mainly referred so the procedure was more thoroughly studied in acid medium. The Fe(III)-SSA complex presented good linearity throughout the measurement range with an DL of 7.32 x 10-3 ppm and an QL of 0.024 ppm achieving a good sensitivity and a recovery percentage of 99.7%. Only SO4-2 presented interference in the sample with a tolerance limit of only 100 ppm. The standard addition method was effective to eliminate this interference by treating the entire matrix in the same way throughout the measurement range. Potable water samples were taken from different sources, such as, from the Analytic Chemistry Laboratory (Ñuñoa), Quinta Normal and from a construction zone adjacent of the the Faculty of Sciences of the University of Chile. Fe is generally found at concentrations below the norm (23.38 ppb and 172 ppb), but is sensitive to climatic factors (522 ppb after a very rainy day) and construction places with little waste treatment (342.3 ppb), so it must be constantly monitored. Solid phase extraction is a simple, fast and efficient method and has a wide range of applications for different compounds or chemical substances.

La nanocalorimetria abre la posibilidad de realizar medidas calorimétricas en capas finas o ultra finas debido al substancial aumento de sensibilidad que presenta respecto a los sistemas comerciales. Basándonos en esa premisa, este trabajo de investigación se ha dedicado al desarrollo de nanocalorimetros basados en membranas que incorporan calentadores y termómetros en capa fina, que permiten reducir la capacidad calorífica de la celda calorimétrica y por tanto al aumento den sensibilidad.En la primera parte de la tesis describimos las técnicas de procesado de semiconductores que se usan para fabricar los microdispositivos con una especial atención a su estabilidad térmica a alta temperatura. Se muestra que usando como actuador una la combinación metálica de Pt/Ti cubierta por Al2O3, se puede utilizar con gran reproducibilidad para calentar/sensar hasta temperaturas de alrededor de 1200K.La nanocalorimetria adiabática se presenta en el capitulo 4. La técnica trabaja a ritmos de calentamiento alrededor de 104 K/s. A estos ritmos de calentamiento se pueden estudiar transformaciones de fase en capas ultrafinas con una sensitividad en energía inferior al nJ. El ruido pico a pico asociado a las medidas de capacidad calorífica es de alrededor a 20 pJ/K, para transformaciones reversibles. La dependencia con el tamaño del punto de fusión y de la entalpía de transformación para capas finas de In se han analizado como estudio preliminar. También presentamos una nueva metodología para poder evaluar la potencia de pérdidas a altas temperaturas. Empleando esta metodología se ha determinado la capacidad calorífica de capas muy finas de Ni alrededor de la transición de curie. Se presencia un estudio en el que se evidencia como los efectos de tamaño tienen un rol fundamental en la transición. La última parte de este capítulo presenta el análisis de capas ultrafinas de Ge encapsuladas entre capas de SiO2 cuando son sometidas a calentamientos ultrarápidos hasta 1200K. Se describen la transformación de amorfo a líquido así como la dependencia con el tamaño de la fusión y el sobreenfriamiento de nanocristales de Ge.En el capítulo 5 presentamos un nuevo sistema de control digital que hemos desarrollado para trabajar con los nanocalorímetros en modo compensación de potencia a ritmos de calentamiento que se expanden desde 0.1 hasta 103 K/s. Este sistema ha permitido analizar muestras de microgramos con sensitividades energéticas de µJ. Este nuevo desarrollo abre la posibilidad al estudio de transformaciones cinéticamente limitadas que típicamente necesitan de ritmos de calentamiento bajos, como por ejemplo para analizar los procesos de RTA (rápidos recocidos térmicos) usados en la industria microelectrónica.Finalmente, en los apéndices tratamos la teoría de control calorimetría y la cristalización de capas finas de Ge de diferentes espesores. / Thin film calorimetry opens the possibility to perform calorimetric measurements on ultra-thin or thin films due to the substantial increase in sensitivity compared to commercial systems. Based on this premise, the present research work deals with the development of membrane-based nanocalorimeters incorporating thin film heaters and thermometers which can work with high sensitivity because of their very low thermal mass. In the first part we describe semiconductor processing techniques that are used to fabricate the microdevices with a special care devoted to their high temperature thermomechanical stability. It is shown that alumina coated Pt/Ti resistive elements can be reproducibly used for heating/sensing up to temperatures around 1200 K. Quasi-adiabatic nanocalorimetry is presented in Chapter 4. The technique works at heating rates above 104 K/s. At these rates phase transitions in ultra-thin films can be measured with energy sensitivity in the nJ range. The associated noise in heat capacity is around 20 pJ/K, for reversible transitions. The size-dependent melting point and enthalpy of ultra-thin films of In is analyzed as a case study. A new methodology to account for power losses at high temperatures is presented in this chapter. By employing this methodology the heat capacity of very thin films of Ni at the Curie transition is determined. It is shown that size effects also play a key role in this transition. The last part of this chapter is devoted to the analysis of ultra-thin films of Ge embedded within SiO2 layers during ultrafast heating up to 1200K. The melting of the amorphous phase along with the size-dependent melting and supercooling of Ge nanocrystals is also described. In Chapter 5 we present a new digital-based control system which has been developed to work in power compensation mode at heating rates spanning from 0.1 to 103 K/s. It permits to analyze samples in the microgram range with a energy sensitivity around the µJ. This new development opens the possibility to study kinetically limited transformations that typically need for lower rates or to mimic real conditions similar to those achieved in rapid thermal processing in the microelectronic industry. Finally, several appendix dealing with control theory, calorimetry and the crystallization of Ge films of different thickness are also presented.

El checkpoint de la fase S constitueix una barrera anti-càncer. Quan aquest mecanisme de vigilància detecta situacions que posen en perill la integritat genòmica, tals com dany al DNA o estrès replicatiu, genera una resposta que engloba la protecció de la replicació, l'aturada del cicle cel·lular i l'activació i coordinació dels sistemes de reparació del DNA. En última instància, si la crisi no es superada el checkpoint promou l'entrada en apoptosis via p53. Per aquest motiu, la mutació d'elements d'aquest mecanisme de control ha estat àmpliament implicada en tumors primaris humans, ja que afavoreixen l'aparició d'inestabilitat genòmica, un dels motors de la transformació cel·lular maligna. A pesar de la importància d'aquest mecanisme de vigilància en el seu paper antitumoral, la gran majoria de les seves dianes romanen desconegudes. Per tal d'identificar noves seqüències implicades en la resposta, es van realitzar 2 aproximacions a gran escala, obtenció de proteomes 2D-DIGE checkpoint dependents utilitzant com a model S. cerevisiae i l'obtenció de microxips d'expressió en resposta a estrès replicatiu en cèl·lules HeLa. Finalment, van permetre identificar la ciclina E2 com a nova diana del checkpoint de fase S. La ciclina E2 és imprescindible perquè les cèl·lules pugin superar la transició G1/S, comprometent-se a una ronda de cicle cel·lular. En resposta a estrés genotòxic és acumulada de forma dependent de l'activació del checkpoint de la fase S. Aquesta estabilització implica alts nivells del seu mRNA i requereix síntesi de novo continuada. Els nostres resultats indiquen que l'acumulació de ciclina E2 podria actuar alentint la progressió de la fase S, evitant d'aquesta manera que cromosomes danyats siguin segregats en mitosis aberrants. Per altra banda, la ciclina E2 es troba sobreexpressada en un elevat número de tumors primaris. Donada la seva implicació en la resposta del checkpoint, vam avaluar si presenta modulació a la resposta a agents quimioteràpics que afecten l'estructura del DNA. Els assaigs de viabilitat in vitro enfront a inhibidors de la topoisomerasa I, mostren que la ciclina E2 confereix resistència enfront la teràpia. Per tant, de confirmar-se aquests resultats in situ, podria ser utilitzada com a biomarcador de resposta. / The S-phase checkpoint acts as an anti-cancer barrier. When the surveillance mechanism detects dangerous situations for the genome integrity such as DNA damage or replication stress, the S-phase checkpoint generates its own response, including replication protection, cell cycle arrest and activation and coordination of DNA repair systems. Finally, if stress situation is not by-passed, the S-phase checkpoint induces cell death through apoptosis via p53. For these reasons, mutations in the mechanism elements are widely related with tumorogenesis processes, because they arise the emergence of genome instability, a driving force of malignant cell transformation. Despite the importance of this mechanism in its anti-cancer role, most of its targets are still unknown. To identify new sequences involved in the response, we used two high-throughput approaches: checkpoint-dependent 2D-DIGE proteomes in S. cerevisiae under replication stress conditions and expression microarrays in replication stress conditions using human HeLa cells. Finally we identified cyclin E2 as a novel S-phase checkpoint target. Cyclin E2 is essential to cells to by-pass G1/S boundary, entering in cell cycle. Cyclin E2 levels are stabilized in a S-phase checkpoint dependent manner. This stabilization involves the cyclin E2 mRNA increase and the continuous de novo synthesis of the protein. Our results indicate that cyclin E2 accumulation could delay the S-phase progression, avoiding the segregation of partially replicated chromosomes in aberrant mitosis. On the other hand, as cyclin E2 has been found over-expressed in a high number of human primary tumours, we next tested if the over-expression of cyclin E2 could modulate the response to DNA-based chemotherapy agents. Viability in vitro assays confirmed that cyclin E2 confers resistance to toisomerase I inhibitors. This result postulates cyclin E2 tumour levels as a prediction biomarker for chemotherapy response.

D'entre els defectes organolèptics associats al vi, en destaca l'anomenat "gust de suro" habitualment vinculat a la presència de cloroanisoles, els quals són productes de l'activitat microbiana formats a partir dels corresponents clorofenols. La present tesi doctoral recull, en primer lloc, metodologies analítiques adreçades principalment a la determinació dels compostos clorofenòlics (2,4,6-triclorofenol, 2,3,4,6-tetraclorofenol i pentaclorofenol) en el control de qualitat dels taps suro, emprant dissolucions hidroalcohòliques com a medi de maceració o d'extracció i utilitzant les tècniques d'extracció en fase sòlida (SPE) i microextracció en fase sòlida (SPME) acoblades a la cromatografia de gasos (GC).En segon lloc, per tal de dur a terme l'anàlisi de cloroanisoles juntament amb els seus precursors en matrius de suro s'ha avaluat un mètode basat en l'extracció amb dissolvent orgànic, el qual ha estat aplicat per a l'estudi de diferents sistemes d'eliminació d'aquests anàlits en la matriu citada. En darrer lloc, s'han proposat metodologies per l'anàlisi de mostres de vi, en les quals d'una banda s'han determinat els compostos clorofenòlics utilitzant la SPME i de l'altra el 2,4,6-tricloroanisole i el 2,4,6-tribromoanisole mitjançant l'acoblament de la SPE i la injecció de grans volums (LVI) en el sistema cromatogràfic. / The organoleptic defect known as cork taint is associated with a musty or mouldy aroma in wine. Chloroanisoles, which are produced through a process of detoxification by fungal methylation of chlorophenolic compounds, are considered to be the main contributory substances. In the present work, analytical methods for the determination of chlorophenols (2,4,6-trichlorophenol, 2,3,4,6-tetrachloropheol and pentachlorophenol) in cork matrices using the solid-phase extraction (SPE) and the solid-phase microextraction (SPME) as preconcentration techniques were evaluated. Therefore, hydroalcoholic solutions have been proposed as extractant solvent in order to test the quality of cork stoppers.Furthermore, a methodology based on extraction with an organic solvent for the simultaneous determination of chloroanisoles and chlorophenols in cork matrices was proposed. This methodology was applied with the aim of checking the efficiency of several washing treatments to remove the target analytes in naturally contaminated cork samples.Finally, different procedures have been developed for the analysis of wine samples. On one hand, chlorophenols were quantified by employing a SPME method. On the other hand, a reliable SPE method coupled to large volume injection was proposed for the determination of both 2,4,6-trichloroanisole and 2,4,6-tribromoanisole.

En este trabajo se ha realizado una simulación numérica detallada del fenómeno de cambio de fase sólido-líquido, por ser esta fenomenología de gran interés en diferentes áreas industriales. La simulación realizada implica problemas de no linealidad, fuertes acoplamientos y frontera móvil. Como resultado de esto, solo para las configuraciones más simples se pueden utilizar herramientas analíticas, mientras que para resolver la mayoría de problemas de interés se requiere el uso de métodos numéricos. Estos métodos consisten en discretizar las ecuaciones que definen la fenomenología que nos ocupa en pequeñas celdas o volúmenes de control. En este estudio se ha optado por utilizar el Método de Volúmenes Finitos (FVM) para la discretización de las ecuaciones gobernantes utilizando mallas cartesianas. Se utiliza una malla desplazada; esto quiere decir que las componentes del vector velocidad se calculan en las caras de los volúmenes de control, lo que permite un acoplamiento adecuado entre la ecuación de conservación de la masa y momentum. Tanto el código como las soluciones numéricas han sido convenientemente verificados. La verificación del código consiste en comprobar que éste está libre de errores de programación y que el comportamiento de los esquemas numéricos implementados está acorde con su comportamiento teórico. Para la verificación de la solución numérica se han utilizado métodos de extrapolación de Richardson o realizando un estudio de refinamiento de malla y observando la evolución de algunas magnitudes características del problema como pueden ser la fracción de líquido en el dominio o el número de Nusselt en la pared caliente.Una vez que el código y las soluciones numéricas han sido convenientemente verificados, la validación final de la simulación del proceso es la que se obtiene de comparar los resultados predecidos con los datos experimentales.El problema de la fusión del galio en una cavidad rectangular calentada por un lado ha sido ampliamente utilizado por investigadores con el fin de evaluar los métodos numéricos para la resolución del cambio de fase. Si bien comentar que este material tiene las ventajas de que sus propiedades termofísicas están bien establecidas, que tiene una temperatura de cambio de fase cercana a la temperatura ambiente y que es un material con gran interés industrial, también presenta algunas desventajas como es el hecho de que tiene un comportamiento anisotrópico en cuanto a la conductividad térmica de la fase sólida. No obstante, el gran número de trabajos experimentales que se encuentran en la literatura relacionados con este material nos ha conducido a escoger este material para la realización de un estudio detallado del cambio de fase sólido-líquido en este trabajo.Si bien en la literatura aparece este problema con diferentes configuraciones, en este trabajo nos hemos centrado en el estudio del caso en que la relación de aspecto (alto/ancho) es de 0,5.Existen diferentes métodos numéricos pararesolver problemas de cambio de fase sólido líquido: métodos que siguen la frontera móvil, métodos que fijan la frontera móvil, etc. En este trabajo utilizaremos el Método Entálpico pues nos permite utilizar una malla fija en todo el dominio, la condición de Stefan queda impuesta de manera implícita, permite la coexistencia de más de un frente de cambio de fase y permite que la interfase tenga un cierto grosor. El caso que nos ocupa tiene la singularidad de encontrarse en un rango de Prandtl muy bajo. Esto provoca que se alcance el régimen turbulento para números de Rayleigh relativamente bajos. Esto nos ha hecho pensar sobre la conveniencia de realizar un estudio más detallado para determinar para que valor de Rayleigh se produce la transición de régimen permanente a flujo oscilatorio y de éste a un régimen caótico. Los problemas que han ido surgiendo a lo largo de la realización de este trabajo nos han conducido a la utilización del método multibloc, también conocido como método de descomposición de subdominios. El método se emplea considerando flujos incompresibles y mallas desplazadas. En este trabajo se explicarán las modificaciones que han sido necesarias para la utilización de este método en la fenomenología del cambio de fase sólido líquido. Se han utilizado dos aproximaciones: una conservativa y otra basada en la presión. Para la obtención de la solución de referencia se ha empleado los métodos de subdominios basados en la presión, pues con el método conservativo se han observado discrepancias entre la solución obtenida con un único subdominio y la obtenida con varios subdominios. Finalmente, se ha realizado un estudio parámetrico del caso, para el cual se han considerado diferentes relaciones de aspecto, diferentes condiciones de contorno y variaciones de ±10% en las propiedades termofísicas con respecto al caso de referencia, con el objetivo de ver como afectan estas modificaciones sobre la fenomenología que nos ocupa. / In this thesis a detailed numerical simulation of liquid-solid phase change phenomena has been made, because this phenomenology is of great interest in different industrial areas. The simulation done implies problems of nonlinearity, strong couplings and movable interphase. Like a result, only for the simplest configurations analytical tools can be used, whereas to solve the most of interest problems numerical methods are needed. These methods consist in the discretisation of the equations that define the phenomenology in small cells or control volumes. In this study the Finite Volume Method (FVM) has been used for the governing equations discretisation using Cartesian meshes. A displaced mesh is used; this means that the components of the speed vector are calculated in the faces of the control volumes, which allows a correct coupling between the continuity and momentum equations. So the code as the numerical solutions have been properly verified. The code verification consist of verifying that this is free of programming errors and that the behaviour of the numerical schemes is agreed with the theoretical one. For the verification of the numerical solution the Richardson Extrapolation Method or a mesh refinement study have been used. Once the code and the numerical solutions have been properly verified, the final validation of the process simulation is obtained comparing the numerical results with experimental ones.The Gallium melting problem in a square cavity heated by a side has been widely used by investigators with the objective of evaluatingthe numerical methods used for solving the phase change phenomena. Although this material have the advantages of its thermophysical properties are well established, the phase change temperature is near the room temperature and is a material with a great industrial interest, also presents some disadvantages like having an anisotropic thermal conductivity of the solid phase. However, the great number of experimental works that can been found in the literature, lead us to choose this material for doing a detailed study of the solid liquid phase change in this work. Although in the literature this problem appears with different configurations, in this thesis we have centered in the study of the case with an aspect ratio (height/width) of 0.5. Different numerical methods exist to solve solid-liquid phase change problems: methods that follow the moving interphase, methods that fix the moving interphase, etc. In this work we have used the Enthalpy Method because it allows us to use a fixed mesh in all the domain, the Stefan condition is imposed implicitly, it allows the coexistence of more than one front of phase change and allows the interphase has a thickness.This case has the singularity of being in a low Prandtl number range. This causes that a turbulent state has been reached for relatively low Rayleigh numbers. This has made think us on the convenience of making a detailed study to determine the transition of permanent regime to oscillating flow and from oscillating flow to chaotic regime. The problems than have been found in the accomplishment of this work have lead us to the use of multiblock method. This method is used considering incompressible flows and moved meshes. We will explain the modifications that have been necessary for using this method in the phase change phenomena. Two approaches have been used: a conservative one and a pressure based one. For obtaining the reference solution has been use the pressure based method, because the conservative method presents discrepancies between the obtained solution with an only subdomain and the obtained with several subdomains. Finally, a parametric study has been done, considering different aspect ratios, boundary conditions and variations of ±10% in the thermophysical properties with respect to the reference case, with the objective to see as these changes affect on the phenomenology that occupies to us.

El objetivo de la tesis es estudiar en términos del ruido de fase, el diseño de osciladores de microondas sintetizados. La tesis realiza una revisión tecnológica de los componentes habitualmente empleados, en términos de ruido de fase, estableciendo las prestaciones y limitaciones de los subsistemas, analizando e incorporando las no alinealidades al método de diseño.Asimismo se realiza una caracterización experimental consistente en la medida del ruido de fase de los subsistemas y en la propuesta de un método innovador para la medida de la función de transferencia del pll. La tesis establece a partir de un catalogo de medidas, los criterios de diseño a seguir para la optimización de un oscilador sintetizado a frecuencias de microondas.

Estudamos um Hamiltoniano exatamente solúvel que modela um condensado de Bose- Einstein hetero-triatômico molecular. Este modelo descreve a mistura de duas espécies de átomos em proporções diferentes que podem se combinar e formar uma molécula triatômica. Começando por uma análise clássica, nós determinamos os pontos fixos do sistema. Bifurcações destes pontos fixos separam o espaço de parâmetros em diferentes regiões. Três cenários distintos são encontrados, dependendo da diferença hetero-atômica. Estes resultados sugerem que as propriedades do estado fundamental do sistema exibem uma sensibilidade à diferença hetero-atômica. Subseqüentemente, nós fazemos uma análise quântica do sistema, utilizando diferentes técnicas, como a dinâmica quântica, valores esperados, o gap de energia e a fidelidade. Nós encontramos que os resultados da análise quântica confirmam as previsões da análise clássica. / We investigate an integrable Hamiltonian modelling a hetero-triatomic-molecular Bose- Einstein condensate. This model describes a mixture of two species of atoms in different proportions, which can combine to form a triatomic molecule. Beginning with a classical analysis, we determine the fixed points of the system. Bifurcations of these points separate the parameter space into different regions. Three distinct scenarios are found, varying with the atomic population imbalance. This result suggests the ground state properties of the quantum model exhibits a sensitivity on the atomic population imbalance, which is confirmed by a quantum analysis using different approaches, such as the ground-state expectation values, the behaviour of the quantum dynamics, the energy gap and the ground state fidelity.

O conceito de heterogeneidade de tamanhos de domínios (Heq), definido como o número de tamanhos distintos de domínios existentes em determinada configuração de um sistema, foi recentemente introduzido no contexto do modelo de percolação explosiva. Além de introduzir um novo expoente de escala, o mesmo se mostrou útil em outros problemas da mecânica estatística de equilíbrio, como o de percolação aleatória, bem como nos modelos de Ising e Potts. Neste trabalho, aplicamos e medimos esta quantidade em situações fora do equilíbrio. Em particular, após submetermos os modelos de Ising e Potts a um súbito resfriamento, a partir de um estado de equilíbrio de alta temperatura, para uma temperatura crítica ou subcrítica, T > Tc, medimos a evolução temporal de H(t). Mostramos que o comportamento para tempos grandes é uma lei de potência com expoentes diferentes para os casos crítico e subcrítico. Adicionalmente, o comportamento para tempos pequenos apresenta ainda um máximo no valor de H(t), quando a temperatura inicial é T0 → Ѡ. Apresentamos um extenso conjunto de dados de simulação que apoiam essas conclusões e discutimos perspectivas futuras, com o objetivo de tentar compreender melhor o comportamento de H(t). / The concept of domain size heterogeneity (Heq), the number of distinct domain sizes occurring in a given con guration, was recently introduced in the context of explosive percolation. Besides introducing a new scaling exponent, it was shown to be useful in other classical equilibrium statistical mechanics problems, like random percolation, and the Ising and Potts models. Here we apply and measure this quantity for out of equilibrium situations. In particular, after quenching the Ising and Potts models from a high temperature equilibrium state, T > Tc, to a critical or subcritical temperature, T Tc, we measure the time evolution of H(t). We show that the long time behavior is power law with di erent exponents for critical and subcritical coarsening. Moreover, the short time behavior also presents a surprising maximum of H(t) when the initial temperature is T0 → Ѡ. We present extensive simulation data supporting these conclusions and discuss future perspectives, in order to help understand the overall behavior of H(t).

No presente estudo, a capacidade de adsorventes potenciais (sílica, alumina, carvão, crisotila nativa e tratada) frente à adsorção de acetona em cicloexano foi avaliada segundo modelo de Langmuir e Freundlich. Nestes sistemas observa-se que o modelo de Langmuir é o que melhor representa o sistema, apontando para uma adsorção química em monocamada, onde carvão seria o adsorvente com a maior capacidade de interação, seguido por alumina, sílica, crisotila tratada e nativa. Os adsorventes foram caracterizados através de técnicas de Análise porosimétrica (adsorção de nitrogênio), Difração de Raios-X (XRD), Espectroscopia molecular de Infravermelho (FT-IR e DRIFTS), Microscopia Eletrônica de Varredura com Análise de Raios-X em Dispersão de Energia (SEM-EDX), onde se observaram as peculiaridades de cada adsorvente.Nas reações de polimerização que visaram avaliar os adsorventes modificados com metal (sílica, crisotila nativa e tratada), observou-se que para sistemas suportados, os melhores resultados de polimerização – maiores atividades- ocorreram quando a sílica foi dopada com 10% de metal, independente do metal utilizado. Para o mesmo catalisador, tanto a crisotila tratada, quanto à nativa mostraram-se mais eficientes quando dopadas com 50% de metal. A eficiência na utilização da técnica de Micro-Extração em fase sólida (SPME) em nosso sistema foi comprovada visto que os limites de detecção foram bastante baixos, possibilitando a avaliação da capacidade de retenção de acetona pelo adsorvente. / In the present study, the capacity of potential adsorbents (silica, alumina, coal, native and treated chrysotile) front the adsorption of acetone in cyclohexane was evaluated according to Langmuir and Freundlich models. In these systems Langmuir model represents better the system, represented a chemical monolayer adsorption, where coal would be bigger adsorption capacity, followed by alumina, treated chrysotile, silica and native chrysotile. The adsorbents characterized through porosimetry Analysis (nitrogen adsorption), X-Ray Diffraction (XRD), Fourier Infrared Spectroscopy (FT-IR and DRIFTS), Spectroscopy Electronic Microscopy in Energy Dispersion X-Ray (SEMEDX) techniques, where was observed the adsorbents peculiarities. In polymerization reactions was evaluated the metal modified adsorbents (silica, native and treated chrysotile), it was observed that supported systems, the betters polymerization results - bigger activities had occurred when silica was doped with 10% metal, independent of metal used. For same catalytic, as treated chrysotile, as long native chrysotile revealed better efficient when doped with 50% metal. The efficiency in use of Solid-phase microextraction (SPME) technique in our system was proved with the low limits of detention, becoming possible the evaluation of acetone capacity of adsorbent retention.