Análisis numérico y experimental del agrietamiento transversal en laminados cruzados simétricos

Este trabajo, está orientado a los materiales compuestos laminados de aplicación en las estructuras aeroespaciales. Una de las principales características que los hacen ventajosos son los elevados cocientes resistencia/peso y rigidez/peso; esto es, si se compara la densidad de una aleación de aluminio con la densidad de un material compuesto de fibra de carbono con matriz de resina epoxi, el material compuesto es 1,77 veces más liviano que la aleación de aluminio; de igual modo, si se compara la resistencia a tracción del material compuesto con la aleación de aluminio, el material compuesto de fibras de carbono con matriz de resina epoxi es 3,21 veces más resistente. Sin embargo, los materiales compuestos laminados tienen poca resistencia en la dirección transversal, por lo que es necesario colocar láminas a 90 grados durante el apilado para obtener una mayor resistencia en la dirección transversal. En particular los análisis realizados en esta investigación se han centrado en los laminados cruzados simétricos sometidos a cargas de tracción. Un laminado cruzado es un conjunto de dos o más láminas pegadas entre sí dispuestas de forma simétrica a 0º y 90º. Las láminas externas se disponen en la dirección de la carga (0º) y la interna perpendicular a la misma (90º), y actúa como un elemento integral estructural.

Preenchimento de cavidades provenientes de remoção de trinca em turbinas hidráulicas por meio do processo GMAW-P

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2016.

Efeito antibacteriano de tecidos têxteis revestidos por prata através da técnica de deposição por plasma

In this study, it has been investigated the influence of silver film deposition onto 100% polyester woven and non-woven, on the survival of Escherichia coli and Staphylococcus aureus in contact with these surfaces. The treatment was performedin a chamber containing the working gas at low pressure (~ 10-2 mbar). Some process parameters such as as voltage: 470 V; pressure: 10-2 mbar; current : 0.40 A and gas flow: 6 and 10 cm3/min were kept constant. For the treatments with purêargon plasma using a flow of 6 and 10 cm3/min, different treatment times were evaluated, such as, 10 , 20, 30, 40, 50 and 60 minutes. Contact angle (sessile drop), measurements were used to determine the surface tension of the treated fabrics and its influence on the bacteria grow as weel as the possibilities of a biofilm formation. The formation of a silver film, as well as the amount of this element was verified byEDX technique. The topography was observed through scanning electron microscopy (SEM) to determine the size of silver grains formed on the surfaces of the fabric and assess homogeneity of treatment. The X-ray diffraction (XRD) was used to analyze the structure of silver film deposition. The woven fabric treatments enabled the formation of silver particulate films with particle size larger than the non-woven fabrics. With respect to bacterial growth, all fabrics were shown to be bactericidal for Staphylococcus aureus (S. aureus), while for the Escherichia coli (E. coli), the best results were found for the non-woven fabric (TNT) treated with a flow of 10 cm3/min to both bacteria

Aprendizaje transversal para potenciar las competencias en el itinerario curricular de los estudiantes

Los estudiantes de diferentes facultades, escuelas y campus de la Universidad tienen la posibilidad de desarrollar y poner en práctica competencias y habilidades comunicativas en un Concurso de Oratoria. La tercera edición del concurso estuvo patrocinada por el video “Tu mejor sonrisa”: https://youtu.be/DCh0pF37jUc

Importance in the acquisition of the transversal competences in the degree of law

This project aims to clarify the importance of acquiring cross-disciplinary competencies in the Law and Criminology degrees, specifically entrepreneurial capability in order to further students' comprehensive training and complete preparation for the legal and professional sector, thereby fostering students' greater involvement in the development of such competencies.

Síntomas musculoesqueléticos de la región dorsolumbar y hábitos de vida en trabajadores de una empresa de construcción, Bogotá, 2016: estudio de corte transversal

RESUMEN El dolor dorso lumbar es un síntoma que afecta a gran cantidad de personas y población trabajadora en el mundo y comprende un importante problema de salud. La prevalencia de dolor de espalda baja en población trabajadora se estima en un 60% a un 85%, mientras que la prevalencia anual en la población general varía entre un 15% al 45%. La incidencia anual de dolor de espalda en la población general se estima entre 10% y 15%. Objetivo Determinar la prevalencia de síntomas musculoesqueléticos de la región dorso lumbar y los hábitos de vida de trabajadores en una empresa de construcción en la ciudad de Bogotá. Metodología Se realizó un estudio de corte transversal. Se analizaron datos secundarios procedentes de una base de datos de una empresa de construcción ubicada en la ciudad de Bogotá, con 282 trabajadores. Se incluyeron variables sociodemográficas, laborales, hábitos de vida y síntomas musculoesqueléticos. Se hizo un análisis descriptivo considerando las medidas de tendencia central para las variables cuantitativas y distribución de frecuencias para variables cualitativas. Resultados Se incluyeron a 282 trabajadores con un promedio de edad de 33.4 años (DE=10.2). El 93% correspondió al sexo masculino. La prevalencia de síntomas musculoesqueléticos en región dorsal fue de 26% y región lumbar 31.2%. La mayoría de trabajadores se encuentra en el área operativa con un 87,9% en la tercera década de la vida y con un tiempo en la empresa de 11 a 18 años (42.8%). Otros factores que se asociaron con la presencia de síntomas en la región dorsolumbar fueron: realizar oficios domésticos, el sedentarismo y dormir menos de 6 horas. Conclusiones Los síntomas musculoesqueléticos derivados de la actividad laboral en la construcción constituyen un problema significativo influenciado por los factores de riesgo relacionados con el trabajo, las características sociodemográficas y hábitos de vida que pueden jugar un papel fundamental para la aparición de sintomatología. Por lo tanto, se requiere que los trabajadores sean incluidos en programas de vigilancia epidemiológica, con el fin de establecer acciones de prevención que permitan disminuir la aparición de dichos síntomas.

La investigación como eje transversal en el desarrollo de los cursos de la carrera en la Enseñanza de la Educación Física

The purpose of this article is to provide with brief reflections to faculty in order to give them practical advices using research as a transversal axis in a defined pedagogical strategy applicable to the courses offered by the School of Sport Science (SSS). In other words, we intend to emphasize the role of research by reaching professional profiles and developing the courses offered by the School of Sport Science (SS). Finally, a hypothetic example was used to explain each step in relationship to the research protocol from a positivistic perspective.

A EDUCAÇÃO AMBIENTAL COMO TEMA TRANSVERSAL NO ENSINO DE GEOGRAFIA: POSSIBILIDADES E LIMITES

A importância da educação ambiental vem crescendo desde a primeira Conferência das Nações Unidas sobre o Meio Ambiente, realizada em Estocolmo, em 1972. Portanto, está atrelada à tomada de consciência sobre os crescentes problemas ambientais em escala local, regional e global. Sua genealogia mais específica pode ser encontrada no seminário realizado pela Unesco em Belgrado, em 1975, no qual foram decididos os objetivos e as diretrizes básicas da educação ambiental, cristalizados na Carta de Belgrado. As conclusões do Relatório Brundtland, publicado em 1987, e a realização da Rio-92 aumentaram a preocupação com a educação ambiental, que então passou a ser contemplada nas legislações nacionais. No Brasil a lei n. 9.795/99 regulamentou a educação ambiental tanto na educação formal quanto na informal e os Parâmetros Curriculares Nacionais contemplaram o meio ambiente como tema transversal no ensino básico. Este trabalho pretende verificar as possibilidades da educação ambiental como tema transversal no ensino de Geografia na escola básica brasileira. Pretende também discutir seus limites num mundo onde há crescente demanda por recursos naturais, crescente consumismo, e que, portanto, tem aumentado os impactos ambientais em diversas escalas geográficas. Parece que há uma expectativa exagerada sobre as possibilidades da educação ambiental.

THE TRANSVERSAL AND THE TRANSDISCIPLINARITY ASPECTS IN THE EDUCATOR FORMATION

We are in a new social configuration, it is necessary to open bigger and bigger spaces for invention, creativity and different ways of working and new methods for making pedagogical rethinking ways of doing education. In this way, the aim of this paper is to present some reflections on teacher education, focusing mainly on the issue of this formation in current contexts. Some questions drive our attention towards clarifying: what knowledge built over the years are needed in order to future educators contextualize them and belonging to the school spaces of their professional performance, and be able to attend the needs of students that are there? To answer this question we consider that it is necessary to change the paradigm of teacher formation to incorporate a design that is in consonance with today's society, acting from a more critical perspective, from an unfragmented model, under transversal and transdisciplinarity aspects. This reformulation should be innovative, but within the reality in which we live.

Performance analysis of adaptive lattice filters for FM signals and alpha-stable processes

The performance of an adaptive filter may be studied through the behaviour of the optimal and adaptive coefficients in a given environment. This thesis investigates the performance of finite impulse response adaptive lattice filters for two classes of input signals: (a) frequency modulated signals with polynomial phases of order p in complex Gaussian white noise (as nonstationary signals), and (b) the impulsive autoregressive processes with alpha-stable distributions (as non-Gaussian signals). Initially, an overview is given for linear prediction and adaptive filtering. The convergence and tracking properties of the stochastic gradient algorithms are discussed for stationary and nonstationary input signals. It is explained that the stochastic gradient lattice algorithm has many advantages over the least-mean square algorithm. Some of these advantages are having a modular structure, easy-guaranteed stability, less sensitivity to the eigenvalue spread of the input autocorrelation matrix, and easy quantization of filter coefficients (normally called reflection coefficients). We then characterize the performance of the stochastic gradient lattice algorithm for the frequency modulated signals through the optimal and adaptive lattice reflection coefficients. This is a difficult task due to the nonlinear dependence of the adaptive reflection coefficients on the preceding stages and the input signal. To ease the derivations, we assume that reflection coefficients of each stage are independent of the inputs to that stage. Then the optimal lattice filter is derived for the frequency modulated signals. This is performed by computing the optimal values of residual errors, reflection coefficients, and recovery errors. Next, we show the tracking behaviour of adaptive reflection coefficients for frequency modulated signals. This is carried out by computing the tracking model of these coefficients for the stochastic gradient lattice algorithm in average. The second-order convergence of the adaptive coefficients is investigated by modeling the theoretical asymptotic variance of the gradient noise at each stage. The accuracy of the analytical results is verified by computer simulations. Using the previous analytical results, we show a new property, the polynomial order reducing property of adaptive lattice filters. This property may be used to reduce the order of the polynomial phase of input frequency modulated signals. Considering two examples, we show how this property may be used in processing frequency modulated signals. In the first example, a detection procedure in carried out on a frequency modulated signal with a second-order polynomial phase in complex Gaussian white noise. We showed that using this technique a better probability of detection is obtained for the reduced-order phase signals compared to that of the traditional energy detector. Also, it is empirically shown that the distribution of the gradient noise in the first adaptive reflection coefficients approximates the Gaussian law. In the second example, the instantaneous frequency of the same observed signal is estimated. We show that by using this technique a lower mean square error is achieved for the estimated frequencies at high signal-to-noise ratios in comparison to that of the adaptive line enhancer. The performance of adaptive lattice filters is then investigated for the second type of input signals, i.e., impulsive autoregressive processes with alpha-stable distributions . The concept of alpha-stable distributions is first introduced. We discuss that the stochastic gradient algorithm which performs desirable results for finite variance input signals (like frequency modulated signals in noise) does not perform a fast convergence for infinite variance stable processes (due to using the minimum mean-square error criterion). To deal with such problems, the concept of minimum dispersion criterion, fractional lower order moments, and recently-developed algorithms for stable processes are introduced. We then study the possibility of using the lattice structure for impulsive stable processes. Accordingly, two new algorithms including the least-mean P-norm lattice algorithm and its normalized version are proposed for lattice filters based on the fractional lower order moments. Simulation results show that using the proposed algorithms, faster convergence speeds are achieved for parameters estimation of autoregressive stable processes with low to moderate degrees of impulsiveness in comparison to many other algorithms. Also, we discuss the effect of impulsiveness of stable processes on generating some misalignment between the estimated parameters and the true values. Due to the infinite variance of stable processes, the performance of the proposed algorithms is only investigated using extensive computer simulations.

The analogue shear zone : from rheology to associated geometry

The geometry of ductile strain localization phenomena is related to the rheology of the deformed rocks. Both qualitative and quantitative rheological properties of natural rocks have been estimated from finite field structures such as folds and shear zones. We apply physical modelling to investigate the relationship between rheology and the temporal evolution of the width and transversal strain distribution in shear zones, both of which have been used previously as rheological proxies. Geologically relevant materials with well-characterized rheological properties (Newtonian, strain hardening, strain softening, Mohr-Coulomb) are deformed in a shear box and observed with Particle Imaging Velocimetry (PIV). It is shown that the width and strain distribution histories in model shear zones display characteristic finite responses related to material properties as predicted by previous studies. Application of the results to natural shear zones in the field is discussed. An investigation of the impact of 3D boundary conditions in the experiments demonstrates that quantitative methods for estimating rheology from finite natural structures must take these into account carefully.

Nonlinear container ship model for the study of parametric roll resonance

Parametric roll is a critical phenomenon for ships, whose onset may cause roll oscillations up to +-40 degrees, leading to very dangerous situations and possibly capsizing. Container ships have been shown to be particularly prone to parametric roll resonance when they are sailing in moderate to heavy head seas. A Matlab/Simulink parametric roll benchmark model for a large container ship has been implemented and validated against a wide set of experimental data. The model is a part of a Matlab/Simulink Toolbox (MSS, 2007). The benchmark implements a 3rd-order nonlinear model where the dynamics of roll is strongly coupled with the heave and pitch dynamics. The implemented model has shown good accuracy in predicting the container ship motions, both in the vertical plane and in the transversal one. Parametric roll has been reproduced for all the data sets in which it happened, and the model provides realistic results which are in good agreement with the model tank experiments.

Tetraspanins as regulators of the tumour microenvironment : implications for metastasis and therapeutic strategies

One of the hallmarks of cancer is the ability to activate invasion and metastasis (Hanahan et al., 2011). Cancer morbidity and mortality are largely related to the spread of the primary, localised tumour to adjacent and distant sites (Pantel et al., 2004). Appropriate management and treatment decisions of predicting metastatic disease at the time of diagnosis is thus crucial, which supports better understanding of the metastatic process. There are common events that occur during metastasis: dissociation from the primary tumour mass, reorganisation/remodelling of extracellular matrix, cell migration, recognition and transversal of endothelial cells and the vascular circulation and lodgement and proliferation within ectopic stroma (Wells, 2006). One of the key and initial events is the increased capability of cancer cells to move, escaping the regulation of normal physiological control. The cellular cytoskeleton plays an important role in cancer cell motility and active cytoskeletal rearrangement can result in metastatic disease. This active change in cytoskeletal dynamics results in manipulation of plasma membrane and cellular balance between cellular adhesion and motility which in turn determines cancer cell movement. Members of the tetraspanins play important roles in regulation of cancer migration and cancer-endothelial cell interactions, which are critical for cancer invasion and metastasis. Their involvements in active cytoskeletal dynamics, cancer metastasis and potential clinical application will be discussed in this review. In particular, tetraspanin member, CD151, is highlighted for its major role in cancer invasion and metastasis

A kinematic analysis of the hand function

Background The evaluation of the hand function is an essential element within the clinical practice. The usual assessments are focus on the ability to perform activities of daily life. The inclusion of instruments to measure kinematic variables provides a new approach to the assessment. Inertial sensors adapted to the hand could be used as a complementary instrument to the traditional assessment. Material: clinimetric assessment (Upper Limb Functional Index, Quick Dash), antrophometric variables (eight and weight), dynamometry (palm preasure) was taken. Functional analysis was made with Acceleglove system for the right hand and computer system. The glove has six acceleration sensor, one on each finger and another one on the reverse palm. Method Analytic, transversal approach. Ten healthy subject made six task on evaluation table (tripod pinch, lateral pinch and tip pinch, extension grip, spherical grip and power grip). Each task was made and measure three times, the second one was analyze for the results section. A Matlab script was created for the analysis of each movement and detection phase based on module vector. Results The module acceleration vector offers useful information of the hand function. The data analysis obtained during the performance of functional gestures allows to identify five different phases within the movement, three static phase and tow dynamic, each module vector was allied to one task. Conclusion Module vector variables could be used for the analysis of the different task made by the hand. Inertial sensor could be use as a complement for the traditional assessment system.

Impact of working conditions on the quality of working life: Case manufacturing sector colombian Caribbean Region [Impacto de las Condiciones de Trabajo en Calidad de Vida Laboral: Caso del Sector Manufacturero de la Región Caribe Colombiana]

La presenta investigación centra su atención en evaluar el impacto de las Condiciones de Trabajo en la Calidad de Vida Laboral del talento humano de sector manufacturero de la región Caribe colombiana. Para analizar este proceso se entrevistaron a 518 empleados del sector. El diseño utilizado fue no experimental de tipo transversal descriptivo, puesto que a cada participante se le aplicó una entrevista con el instrumento de Condiciones de Trabajo y la Herramienta de Calidad de Vida Laboral (Condiciones Salariales y Subjetivas). Los datos fueron analizados mediante análisis de correlación y modelos de regresión logística. Los resultados mostraron que el ambiente térmico y las normas de seguridad en el trabajo afectan de forma positiva la Calidad de Vida Laboral de los empleados del sector. Estos resultados ponen de manifiesto que la relación entre las condiciones de trabajo y la CVL se basa en la competencia y distan de ser una relación lineal y simple relacionada con la consideración de la presencia o la ausencia de las condiciones de trabajo. Ello tiene implicaciones a la hora de formular políticas, programas e intervenciones para prevenir, erradicar y amortiguar los efectos negativos de las condiciones de trabajo y mejorar la seguridad industrial dentro de las empresas.