En este trabajo se investigan las peculiaridades del comportamiento elástico de los filamentos de rayón, que difiere grandemente del de las fibras naturales.Es un resumen de una extensa labor de recopilación bibliográfica, de investiga-ción y de ensayo realizada en 1949 por el autor en una fábrica de tejidos de seda y de rayón de Palma de Mallorca de la cual era Director Técnico. Basándose en el material reunido, el autor pronunció una conferencia sobre este tema en una Velada Técnica organizada por la Asociación Nacional de Ingenieros de Industrias Textiles, el 30 de Mayo de 1949. Un resumen de lo expuesto en ella fue publicado más tarde, en forma de articulo en la revista Ingeniería Textil (nº 80, Noviembre - Diciembre 1949). Se adjunta un ejemplar de la misma.En la época en que se realizó este estudio, aunque ya era corriente en la industria el uso de los distintos tipos de rayón, aún no habían sido bien estudiadas muchas de las propiedades mecánicas de éstos. En particular, la noción de "tiempo" contenida en los conceptos de "alargamiento diferido" y "recuperación diferida" (elasticidad diferida) así como su gran influencia sobre los resultados de las mediciones dinamométricas, constituían una novedad en aquellas fechas.La posterior aparición de las fibras sintéticas y de ciertas materias plásticas, ha si-tuado en primer plano todos estos conceptos que ya habían alcanzado importancia con las fibras artificiales. Los conceptos expresados por el que suscribe en la conferencia y el artículo mencionados, han sido más tarde confirmados y utilizados por otros autores siendo actualmente de uso común.Los métodos estadístico-matemáticos, que habrían resultado muy apropiados para determinar el grado de significación de los ensayos efectuados, no fueron utilizados en este estudio ya que no eran todavía usuales en nuestro país en la época en que fué rea-lizado. / The present paper is a report on the peculiarity of elastic behavior in rayon fibers, which differs very much from such behavior in natural fibers. This research is the summary of extensive work on the bibliography, research and experimental work done by the author in 1949 in a silk and rayon fabric manufactory in Palma de Mallorca, where the author was the technical director. Based on this research, the author gave a conference on the subject in a Technical Ses-sion organized by the Asociación Nacional de Ingenieros de Industrias Textiles (Na-tional Association Engineers of Textile Industries, Spain), on 30 May 1949. The con-ference material was published later as an article in the journal "Ingeniería Textil" (Nº 80, November - December 1949). In spite of the fact that the industry habitually used several types of rayon when this study was originally done, the mechanical properties of these fibers have still not been adequately studied. In particular, the notion of "time" embedded in the concepts of "deferred extension" and "deferred recovery" (deferred elasticity), and their significant influence on the results of dynamometric measures, were novel at that time.The later appearance of synthetic fibers and plastic materials foregrounded these con-cepts, which have remained important in the field of artificial fibers. The concepts ex-amined by the author have lately been confirmed and used by other researchers and are currently in common use.The statistical-mathematical methods that would have been very appropriate for de-termining the signification of the tests done at that early period had not been used in the original study because they were unusual at that time and in our country. This research was motivated by a number of problems and special difficulties that in-volve the manipulation of artificial fibers, mainly rayon.Many phenomena that cause important defects often seem to have no logical explana-tion and frequently induce one to think that the same causes do not always correspond to the same effects. However, that is not true. What in fact is the case is that artificial fibers are recent in industry, and their properties greatly differ from the concepts and norms considered basic and definitive until now. In particular, the concept of "elasticity" is too simple and primitive to explain the var-ied phenomena that take place in artificial fibers submitted to stresses of different kinds. In this article, we propose to enlarge this concept, placing a special emphasis on the relations between elasticity and the factors time and hygrometric state.

In the present study samples were collected from abdominal linea alba aponeurosis of 30 patients (15 males and 15 females) aged from twenty to sixty years [30-59], (Mean=44.9±SD=7.3), with hernia of the anterior abdominal wall to evaluate the immunohistochemistry expression and morphometry of the elastic fibers. Nine of the patients were submitted to surgery at the Hospital de Clínicas in Porto Alegre (HCPA), ten of then at the Santa Casa de Misericórdia do Rio de Janeiro (SCMRJ), seven of them at the author’s private clinic (CA) in Caxias do Sul, and four of them at the Hospital Pompeia (HP) in Caxias do Sul. All patients had a hernia of the anterior abdominal wall. Fourteen of these cases were umbilical hernias, ten epigastric hernias and six incisional hernias. Specimens were collected from the midline three centimeters above the umbilical scar and from two centimeters below it. At the laboratory, the specimens were subdivided in two parts. One of these specimens was stained with orcein and the elastic fibers were counted by digital analysis using the applicative Image Pro Plus (Media Cybernetics, Silver Spring, USA). The other specimen was submitted to evaluation through immunohistochemistry analysis utilizing monoclonal anti-Emilin Antibody to EMILIN1 GP115 Elastin microfibril interface located protein TNF (Proteintech Group), in 1:100 dilution. Findings obtained from these patients were compared to findings obtained in a control group of non formolized cadavers from the Medical Examiner’s Office of Caxias do Sul. In this cadaver control group without hernias, aged from twenty to sixty years [20-59] (Mean= 40.5±SD=11.8), the same studies were carried out as in the surgical group with hernias to evaluate the differences in quantity and morphometry of elastic fibers between the two groups. Results show that the total amount of elastic fibers was 35% higher in patients with hernia of the anterior wall of the abdomen than in the cadaver control group with no hernias (p<.05). / In the present study samples were collected from abdominal linea alba aponeurosis of 30 patients (15 males and 15 females) aged from twenty to sixty years [30-59], (Mean=44.9±SD=7.3), with hernia of the anterior abdominal wall to evaluate the immunohistochemistry expression and morphometry of the elastic fibers. Nine of the patients were submitted to surgery at the Hospital de Clínicas in Porto Alegre (HCPA), ten of then at the Santa Casa de Misericórdia do Rio de Janeiro (SCMRJ), seven of them at the author’s private clinic (CA) in Caxias do Sul, and four of them at the Hospital Pompeia (HP) in Caxias do Sul. All patients had a hernia of the anterior abdominal wall. Fourteen of these cases were umbilical hernias, ten epigastric hernias and six incisional hernias. Specimens were collected from the midline three centimeters above the umbilical scar and from two centimeters below it. At the laboratory, the specimens were subdivided in two parts. One of these specimens was stained with orcein and the elastic fibers were counted by digital analysis using the applicative Image Pro Plus (Media Cybernetics, Silver Spring, USA). The other specimen was submitted to evaluation through immunohistochemistry analysis utilizing monoclonal anti-Emilin Antibody to EMILIN1 GP115 Elastin microfibril interface located protein TNF (Proteintech Group), in 1:100 dilution. Findings obtained from these patients were compared to findings obtained in a control group of non formolized cadavers from the Medical Examiner’s Office of Caxias do Sul. In this cadaver control group without hernias, aged from twenty to sixty years [20-59] (Mean= 40.5±SD=11.8), the same studies were carried out as in the surgical group with hernias to evaluate the differences in quantity and morphometry of elastic fibers between the two groups. Results show that the total amount of elastic fibers was 35% higher in patients with hernia of the anterior wall of the abdomen than in the cadaver control group with no hernias (p<.05).

In the present study samples were collected from abdominal linea alba aponeurosis of 30 patients (15 males and 15 females) aged from twenty to sixty years [30-59], (Mean=44.9±SD=7.3), with hernia of the anterior abdominal wall to evaluate the immunohistochemistry expression and morphometry of the elastic fibers. Nine of the patients were submitted to surgery at the Hospital de Clínicas in Porto Alegre (HCPA), ten of then at the Santa Casa de Misericórdia do Rio de Janeiro (SCMRJ), seven of them at the author’s private clinic (CA) in Caxias do Sul, and four of them at the Hospital Pompeia (HP) in Caxias do Sul. All patients had a hernia of the anterior abdominal wall. Fourteen of these cases were umbilical hernias, ten epigastric hernias and six incisional hernias. Specimens were collected from the midline three centimeters above the umbilical scar and from two centimeters below it. At the laboratory, the specimens were subdivided in two parts. One of these specimens was stained with orcein and the elastic fibers were counted by digital analysis using the applicative Image Pro Plus (Media Cybernetics, Silver Spring, USA). The other specimen was submitted to evaluation through immunohistochemistry analysis utilizing monoclonal anti-Emilin Antibody to EMILIN1 GP115 Elastin microfibril interface located protein TNF (Proteintech Group), in 1:100 dilution. Findings obtained from these patients were compared to findings obtained in a control group of non formolized cadavers from the Medical Examiner’s Office of Caxias do Sul. In this cadaver control group without hernias, aged from twenty to sixty years [20-59] (Mean= 40.5±SD=11.8), the same studies were carried out as in the surgical group with hernias to evaluate the differences in quantity and morphometry of elastic fibers between the two groups. Results show that the total amount of elastic fibers was 35% higher in patients with hernia of the anterior wall of the abdomen than in the cadaver control group with no hernias (p<.05). / In the present study samples were collected from abdominal linea alba aponeurosis of 30 patients (15 males and 15 females) aged from twenty to sixty years [30-59], (Mean=44.9±SD=7.3), with hernia of the anterior abdominal wall to evaluate the immunohistochemistry expression and morphometry of the elastic fibers. Nine of the patients were submitted to surgery at the Hospital de Clínicas in Porto Alegre (HCPA), ten of then at the Santa Casa de Misericórdia do Rio de Janeiro (SCMRJ), seven of them at the author’s private clinic (CA) in Caxias do Sul, and four of them at the Hospital Pompeia (HP) in Caxias do Sul. All patients had a hernia of the anterior abdominal wall. Fourteen of these cases were umbilical hernias, ten epigastric hernias and six incisional hernias. Specimens were collected from the midline three centimeters above the umbilical scar and from two centimeters below it. At the laboratory, the specimens were subdivided in two parts. One of these specimens was stained with orcein and the elastic fibers were counted by digital analysis using the applicative Image Pro Plus (Media Cybernetics, Silver Spring, USA). The other specimen was submitted to evaluation through immunohistochemistry analysis utilizing monoclonal anti-Emilin Antibody to EMILIN1 GP115 Elastin microfibril interface located protein TNF (Proteintech Group), in 1:100 dilution. Findings obtained from these patients were compared to findings obtained in a control group of non formolized cadavers from the Medical Examiner’s Office of Caxias do Sul. In this cadaver control group without hernias, aged from twenty to sixty years [20-59] (Mean= 40.5±SD=11.8), the same studies were carried out as in the surgical group with hernias to evaluate the differences in quantity and morphometry of elastic fibers between the two groups. Results show that the total amount of elastic fibers was 35% higher in patients with hernia of the anterior wall of the abdomen than in the cadaver control group with no hernias (p<.05).

In the present study samples were collected from abdominal linea alba aponeurosis of 30 patients (15 males and 15 females) aged from twenty to sixty years [30-59], (Mean=44.9±SD=7.3), with hernia of the anterior abdominal wall to evaluate the immunohistochemistry expression and morphometry of the elastic fibers. Nine of the patients were submitted to surgery at the Hospital de Clínicas in Porto Alegre (HCPA), ten of then at the Santa Casa de Misericórdia do Rio de Janeiro (SCMRJ), seven of them at the author’s private clinic (CA) in Caxias do Sul, and four of them at the Hospital Pompeia (HP) in Caxias do Sul. All patients had a hernia of the anterior abdominal wall. Fourteen of these cases were umbilical hernias, ten epigastric hernias and six incisional hernias. Specimens were collected from the midline three centimeters above the umbilical scar and from two centimeters below it. At the laboratory, the specimens were subdivided in two parts. One of these specimens was stained with orcein and the elastic fibers were counted by digital analysis using the applicative Image Pro Plus (Media Cybernetics, Silver Spring, USA). The other specimen was submitted to evaluation through immunohistochemistry analysis utilizing monoclonal anti-Emilin Antibody to EMILIN1 GP115 Elastin microfibril interface located protein TNF (Proteintech Group), in 1:100 dilution. Findings obtained from these patients were compared to findings obtained in a control group of non formolized cadavers from the Medical Examiner’s Office of Caxias do Sul. In this cadaver control group without hernias, aged from twenty to sixty years [20-59] (Mean= 40.5±SD=11.8), the same studies were carried out as in the surgical group with hernias to evaluate the differences in quantity and morphometry of elastic fibers between the two groups. Results show that the total amount of elastic fibers was 35% higher in patients with hernia of the anterior wall of the abdomen than in the cadaver control group with no hernias (p<.05). / In the present study samples were collected from abdominal linea alba aponeurosis of 30 patients (15 males and 15 females) aged from twenty to sixty years [30-59], (Mean=44.9±SD=7.3), with hernia of the anterior abdominal wall to evaluate the immunohistochemistry expression and morphometry of the elastic fibers. Nine of the patients were submitted to surgery at the Hospital de Clínicas in Porto Alegre (HCPA), ten of then at the Santa Casa de Misericórdia do Rio de Janeiro (SCMRJ), seven of them at the author’s private clinic (CA) in Caxias do Sul, and four of them at the Hospital Pompeia (HP) in Caxias do Sul. All patients had a hernia of the anterior abdominal wall. Fourteen of these cases were umbilical hernias, ten epigastric hernias and six incisional hernias. Specimens were collected from the midline three centimeters above the umbilical scar and from two centimeters below it. At the laboratory, the specimens were subdivided in two parts. One of these specimens was stained with orcein and the elastic fibers were counted by digital analysis using the applicative Image Pro Plus (Media Cybernetics, Silver Spring, USA). The other specimen was submitted to evaluation through immunohistochemistry analysis utilizing monoclonal anti-Emilin Antibody to EMILIN1 GP115 Elastin microfibril interface located protein TNF (Proteintech Group), in 1:100 dilution. Findings obtained from these patients were compared to findings obtained in a control group of non formolized cadavers from the Medical Examiner’s Office of Caxias do Sul. In this cadaver control group without hernias, aged from twenty to sixty years [20-59] (Mean= 40.5±SD=11.8), the same studies were carried out as in the surgical group with hernias to evaluate the differences in quantity and morphometry of elastic fibers between the two groups. Results show that the total amount of elastic fibers was 35% higher in patients with hernia of the anterior wall of the abdomen than in the cadaver control group with no hernias (p<.05).

Made available in DSpace on 2014-06-12T17:35:33Z (GMT). No. of bitstreams: 2 arquivo3327_1.pdf: 1491088 bytes, checksum: 61d5aa39b1335f04d6e65965ed5c2a81 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / As tensões atuantes em maciços rochosos podem ser tanto de origem natural como induzidas. As tensões de origem natural, ou tensões in situ, dividemse em: gravitacionais, tectônicas, residuais e terrestres. Já as tensões induzidas, são ocasionadas pela ação de obras de engenharia, tais como escavações ou construções. Essas obras alteram o equilíbrio do estado de tensões pré-existente no maciço rochoso, o que implica a necessidade de instalação de um sistema de suporte que garanta a estabilidade e a segurança da estrutura. Este trabalho aborda o desenvolvimento de um modelo matemático, para corpos elásticos ideais, com o objetivo de prever tensões em maciços rochosos puramente elásticos. Para isso, foi lançado mão da teoria da elasticidade e, por simplificação, considerados apenas os efeitos das tensões gravitacionais. Além disso, foi feita a combinação dos parâmetros físicos e geomecânicos de testemunhos de sondagem e a análise do estado plano de tensões em vários pontos ao longo dos furos de sondagem. No desenvolvimento do modelo proposto foi utilizado, como ferramenta de programação, o CENTURA, também conhecido como SQLWINDOWS, que é uma ferramenta de programação usada no desenvolvimento de sistemas cliente/servidor para o ambiente Microsoft Windows e outras plataformas GUI (Graphical User Interface). Na realização dos testes de validação do programa foram considerados três casos hipotéticos: no primeiro, a área trabalhada apresenta um único material; no segundo, a área trabalhada apresenta quatro materiais dispostos em camadas horizontais, e no terceiro, a área trabalhada apresenta cinco materiais dispostos de maneira aleatória

Orientador: Marco Aurelio P. Lima / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-22T00:36:03Z (GMT). No. of bitstreams: 1 Sartori_ClaudioSergio_D.pdf: 19019489 bytes, checksum: 0bb517446ff8bd9279f4ec4c77768b3f (MD5) Previous issue date: 1996 / Resumo: Avanços notáveis em microeletrônica nos últimos anos estão intimamente ligados ao progresso na fabricação de dispositivos e no conhecimento de processos que a envolvem, como plasmas de baixa temperatura, comumente chamados de Plasmas-Frios. O sucesso na fabricação de dispositivos possui ainda hoje um certo caráter empírico, pois pouco se conhece os processos que ocorrem nos ambientes de descarga, havendo uma lacuna no que se refere à dinâmica de colisão entre os elétrons e as espécies em questão (íons, moléculas ou átomos). Portanto, nesses ambientes de descarga, é importante a compreensão dos processos físico-químicos presentes. O estudo de seções de choque de espalhamento de elétrons por moléculas é de fundamental contribuição, pois as colisões de elétrons com as diversas espécies tornam-as altamente reativas. A molécula de H2 é a mais simples molécula a ser estudada, podendo-se aplicar futuramente este trabalho para outras moléculas mais complexas. Para obtenção de seções de choque de espalhamento de elétrons por moléculas, utilizamos o método multicanal de Schwinger, que recentemente tem sido desenvolvido para moléculas mais complexas, acoplando-se a ele pseudopotenciais e possibilitando utilizar os mesmos computadores nos quais realizamos cálculos com moléculas simples. As moléculas durante essas colisões podem estar em seus estados eletrônicos fundamentais ou excitados; quando se encontram em seu estado excitado para calcularmos a seção de choque correspondente, o tempo de vida desse estado deve ser maior que o tempo entre duas colisões e ainda haver um grande número de elétrons com energia suficiente para causar a excitação da molécula para esses estados excitados; isso podemos constatar empregando uma função de distribuição Maxwelliana para os elétrons. Na molécula de H2 há um estado excitado metaestável (c 3Õu) que possui um tempo de vida grande, comparado a outros estados excitados dessa molécula, como o a3Sg(+) e o b3Su(+). Nesse trabalho calculamos seções de choque de espalhamento de elétrons pela molécula de H2, sendo que esta se encontra inicialmente no estado c 3Õu. Esses resultados foram comparados com outras excitações entre estados excitados e com excitações a partir do estado eletrônico fundamental. Análises do comportamento da mudança de Spin do elétron incidente também foram realizadas pelo cálculo da fração de polarização / Abstract: The notable advances made in microelectronics in the last few years are closely linked to progress achieved in the manufacture of devices and knowledge about the processes involved, such as low temperature plasma, commonly referred to as Cold Plasmas. Success in the manufacture of devices still has today certain empiric characteristics, as little is known about the processes occurring in environments where discharges take place, there being a gap about collision dynamics between the electrons and the particles involved (ions, molecules or atoms). Therefore, in such environments it is important to understand the physiochemical processes present. The study of electron-molecule scattering cross sections is of fundamental importance, as electron collision with the several particles makes them highly reactive. The H2 molecule is the simplest molecule to be studied and this work may be used in future to study more complex molecules. To obtain cross sections for electron scattering against molecules we use the Schwinger' s multichannel method which has recently been developed for use with more complex molecules by coupling it with pseudopotential and making it possible to use the same computers in which we do calculations with simple molecules. The molecules may be in their fundamental or excited states during these collisions; in order for them to be in their excited state so we can calculate the corresponding cross section, the life time of this state should be longer than the time between two collisions and there should be a great number of electrons with enough energy to cause the excitation of the molecule to these excited states; we may verify this statement by using a Maxwellian distribution function for the electrons. In an H2 molecule there is a metastable excited state ( c 3Õu) which has a long life time, compared to other excited states of this molecule, such as a3Sg(+) and b3Su(+). In this work we have calculated electron scattering cross sections against the H2 molecule which is initially in the c 3Õu state. These results have been compared to those of other transitions etween excited states and with transitions from the fundamental electronic state. Analyses of spin lip behavior of the incident electron were also carried out by calculating the polarization fraction / Doutorado / Física / Doutor em Ciências

Orientador: Marcio Jose Menon / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-14T22:56:28Z (GMT). No. of bitstreams: 1 Silva_GeovannaLuizPereirada_M.pdf: 9792515 bytes, checksum: 1b4a308cdedc594904027c57497be003 (MD5) Previous issue date: 2009 / Resumo: Apresenta-se um estudo das Representações de Parâmetro de Impacto e Eiconal através de uma análise empírica dos dados experimentais de espalhamento elástico próton-próton, na região de mais alta energia com informações experimentais disponíveis (seis conjuntos de dados no intervalo de energia no centro de massa 19.4 - 62.5 GeV). Fazendo-se uso de uma nova parametrização independente de modelo para a amplitude de espalhamento e através de reduções (ajustes) dos dados experimentais de seção de choque diferencial, determina-se as funções de perfil (partes real e imaginária), recobrimento inelástica e eiconal (partes real e imaginária) no espaço de parâmetro de impacto. Utilizando-se um método semi-analítico, determina-se a função opacidade (parte imaginária da eiconal) no espaço de momento transferido. Todos os resultados empíricos para essas grandezas são determinados com as incertezas correspondentes, calculadas através da propagação de erros dos parâmetros livres de ajuste (variâncias e covariâncias). Em particular, mostra-se que a função de recobrimento inelástica apresenta um efeito periférico em torno de 2,0 fm e que os resultados empíricos para a função opacidade podem ser analiticamente parametrizados por três contribuições gaussianas, dominantes nas regiões de pequeno, médio e grande momento transferido. Discute-se interpretações físicas dos resultados (aspectos ópticos/geométricos e baseados na QCD), bem como a aplicabilidade dos resultados empíricos na seleção, construção e desenvolvimento de modelos fenomenológicos, em particular, aqueles baseados ou inspirados na QCD / Abstract: The Impact Parameter and Eikonal Representations are investigated by means of an empirical analysis of the experimental data on proton-proton elastic scattering, at the highest energy region with experimental information available (six data sets at center of mass energies 19.4 - 62.5 GeV). Making use of a novel model-independent parametrization for the scattering amplitude and data reductions (fits) to differential cross section data, we extract the profile function (real and imaginary parts), the inelastic overlap function and the eikonal function (real and imaginary parts) in the impact parameter space. By means of a semi-analytical method, the opacity function (imaginary part of the eikonal) is also extracted in the momentum transfer space. All the empirical results for these quantities are determined with the corresponding uncertainties, evaluated through error propagation from the free fit parameters (variances and covariances). In particular, it is shown that the inelastic overlap functions present a peripheral effect around 2.0 fm and that the empirical results for the opacity function can be analytically parametrized by three Gaussian components each one with leading contribution at small, intermediate and large values of the momentum transfer. Physical interpretations of the results are discussed (optical/geometrical and QCD-based aspects), as well as the applicability of the empirical results in the selection, construction and development of phenomenological models, mainly those based or inspired in QCD / Mestrado / Física das Particulas Elementares e Campos / Mestra em Física

Magíster en Ciencias, Mención Geofísica / El presente trabajo de tesis tiene como primer objetivo el estudiar y comparar diferentes modelos matemáticos basados en ecuaciones diferenciales parciales y métodos numéricos para modelar y calcular la flexura de una placa litosférica oceánica producida por el efecto combinado de una carga batimétrica tridimensional y la flexión producto de la subducción en la fosa. El segundo objetivo es utilizar la modelación para la resolución de algunos problemas inversos relacionados con la estimación de la variación del espesor elástico efectivo de la placa en ciertas zonas estratégicas y en ciertos casos también de las condiciones de borde en la fosa, y a partir de ello, formular hipótesis sobre el debilitamiento o desgaste de la placa. Inicialmente se aborda el problema de una carga topográfica lejana a una zona de subducción y se encuentra una solución analítica a la ecuación de flexura bidimensional corrigiendo una antigua expresión formulada por primera vez por Hertz [1884] y posteriormente utilizada por varios autores. Luego se aborda el problema donde se combina el efecto de una carga topográfica con el de la subducción para generar un modelo tridimensional. Se proponen dos métodos: el primero resuelve la ecuación del modelo de placa delgada de Kirchhoff-Love (K-L) con espesor elástico constante, y el segundo, resuelve las ecuaciones del modelo Reissner-Mindlin (R-M), ambos mediante el Método de Elementos Finitos (FEM). Para los cálculos se utiliza el programa FreeFem++ que permite definir el problema de forma variacional y que cuenta con la ventaja de poder refinar la malla utilizada en las zonas en donde se requiere mayor precisión en las soluciones. Las estimaciones obtenidas usando el modelo de K-L no ajustan apropiadamente los datos gravimétricos dado que en la formulación se considera que la placa posee un espesor elástico constante, una aproximación poco realista. Además, es sabido que los cálculos basados en el modelo de K-L tienden a producir flexiones significativamente inferiores a las esperadas debido a un fenómeno conocido como shear locking. El modelo de R-M es un modelo más general que el de K-L y constituye una mejor aproximación a la solución exacta, sobretodo cuando se trabaja con placas delgadas. Utilizando una formulación mixta, incorporando un término adicional, es capaz de evitar el fenómeno antes descrito. Además, su formulación permite trabajar con márgenes con geometrías más complejas e incluir el efecto del cambio de dirección de convergencia de las placas con respecto a la normal a éstas. Nos enfocamos en el estudio de la flexión de la placa litosférica en dos zonas particulares. La primera corresponde a una zona sobre la placa de Nazca, entre los 72º-76.5ºW y entre los 32º-34ºS donde se ubican dos prominentes domos volcánicos de la cadena montañosa de Juan Fernández: el O'Higgins Guyot y el Monte O'Higgins. En esta zona se busca calcular la flexión producida por la subducción de la placa en la fosa y por el peso de los montes submarinos ya mencionados. La segunda zona de estudio comprende el área entre los 70º-77ºW y los 14º-23ºS comúnmente denominada el Codo de Arica. Su particular geometría hace que sea necesario trabajar la tridimensionalidad del problema. Un modelo unidimensional, como los que comúnmente se han utilizado, podría sobrestimar el valor de la rigidez flexural, parámetro que caracteriza la resistencia de la placa a flectarse bajo la aplicación de esfuerzos. Del presente estudio se concluye que la edad o el estado termal de la litosfera es sólo uno de los parámetros que influyen en la rigidez flexural, pero no es el más importante. Los resultados indican que la rigidez flexural, y por lo tanto el espesor elástico de la placa, alcanzan valores muy bajos con respecto a lo predicho por un modelo termal en la zona más cercana a la fosa, aquella de mayor edad. Una hipótesis que sería necesario estudiar en mayor profundidad, es que la disminución del espesor elástico podría estar asociado al debilitamiento producto de las deformaciones inelásticas (frágiles o dúctiles) asociadas a la gran magnitud de los esfuerzos involucrados, hidrofracturamiento y con ello aumento de la presión de poros, variación en la composición, fuerzas horizontales o a la gran curvatura.

En la actualidad el mercado carece de prendas elásticas para uso profesional puesto que los elastanos habitualmente utilizados son inestables frente a altas temperaturas y químicos agresivos, e.g. termofijado, mantenimiento de indumentaria industrial etc. Recientemente se han venido utilizado filamentos olefínicos obtenidos a partir de copolímeros al azar de etileno-octeno (Dow XLA fibers producidos por The Dow Chemical Company). Aunque más resistentes a las temperaturas debido a la reticulación, su bajo punto de fusión, alrededor de 50ºC, limita el comportamiento elástico en tejidos pesados y tupidos para indumentaria profesional. La investigación tiene por objeto la obtención de monofilamentos elásticos a partir copolímeros de bloque de etileno-octeno (cuyo punto de fusión es más elevado) y con éstos, tejidos para indumentaria profesional que ofrezcan mayor fuerza de encogimiento a las temperaturas típicas de los pre-tratamientos, tintura y acabado (50ºC-120ºC). El objetivo es hacer que los tejidos encojan más durante las operaciones en húmedo bajo temperatura para mejorar así su elasticidad y aumentar el peso en comparación con los tejidos actuales manufacturados con los convencionales copolímeros homogéneos de etileno-octeno reticulados Los tejidos deberán garantizar las siguientes propiedades durante todo su ciclo de vida: estabilidad dimensional, relación elasticidad-crecimiento mejorado, resistencia química, resistencia térmica, durabilidad ante los lavados industriales y un mejor confort termofisiológico y sensorial. / Due to the lack of stability of elastane based materials against high temperatures and harsh chemicals, e.g. thermofixation and professional wear maintenance, elastic garments with elastane content are not yet fully commercial products. The Dow Chemical Company has recently commercialized a random ethylene-octene copolymer based fiber named Dow XLA fiber. Despite its higher temperature resistance as one of the crosslinking effects, its very low melting point, around 50ºC, establishes some limitations in elasticity such in heavy weight and high densely woven fabric cases typically found in professional wear applications. The target for the investigation is to produce block ethyleneoctene copolymer based filaments in which the melting point is supposed to be higher than in random copolymer materials. Different workwear fabrics will be manufactured with yarns containing such elastic filaments. It is supposed these fabrics to show high shrinkage forces even at dyeing and finishing temperatures, (50ºC-120ºC). The goal is to produce fabrics with superior shrinkage performance in order to achieve an excellent elastic power and the final desired fabric weight. Properties such as dimensional stability, stretch and growth ratio, temperature and chemical resistance and durability against industrial laundering should not be affected by the passage of the time. To validate this point these properties will be measured in the fabrics off loom and after the garment cycle life. These fabrics are also supposed to show better thermophysiological and sensorial properties than random copolymer fiber based textiles

Neste trabalho, foram medidas seções de choque dos espalhamentos elástico e quase-elástico para os sistemas 6,7 Li+120Sn em energias próximas à barreira coulombiana, ELAB = 25,0; 20,5 e 19,5 MeV. Os dados foram analisados através do modelo do potencial de São Paulo que leva em conta os efeitos da não localidade de Pauli em primeira ordem. Foram obtidas as densidades experimentais, na região de superfície, para os isótopos fracamente ligados 6,7Li no estado fundamental a partir da análise de dados de espalhamento quaseelástico, sendo comparadas com aquelas determinadas a partir de uma grande sistemática, com base em cálculos do tipo Hartree-Fock-Boguliobov. A discordância observada entre as densidades teóricas e experimentais, particularmente para o núcleo 7Li, foi interpretada com base nos processos de quebra e efeitos de acoplamento com estados do contínuo. A descrição dos dados de espalhamento elástico para ambos os sistemas está de acordo com as recentes informações acerca dos efeitos da anomalia de limiar associados ao processo de quebra de núcleos fracamente ligados. / In this work, the elastic and quasi-elastic cross sections for the systems 6,7Li +120 Sn, for the near barrier energies, ELAB = 25.0; 20.5 and 19.5 MeV, have been measured. The data have been analyzed in the framework of the parameter free São Paulo potential, which takes in account the non-local exchange effects in first order. From the quasi-elastic data analysis, the experimental nuclear densities in the surface region for the weakly bound nuclei 6,7Li have been extracted and compared with those from a systematic based on Hartree-Fock-Boguliobov calculations. The deviation for 7Li, was interpreted due to the projectile break-up and couplings to continuum effects. The elastic data description for both systems is in agreement with the recently reported break-up threshold anomaly.