998 resultados para Viscoelastic Bi-Materials
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En aquest projecte es presenta un estudi sobre punxonats i esbocats per a materials d’Alt límit elàstic (Acers AHSS; Advanced High Strength Steels), amb l’objectiu d’aconseguir saber quin és el millor procés de tall per aconseguir esbocats correctes. Utilitzant la premsa hidràulica de la Fundació Centre Tecnològic de Manresa (CTM) es realitza el punxonat i els esbocats a tots els materials per tal d’avaluar el seu comportament alhora de ser esbocats. A partir d’aquests resultats obtindrem les gràfiques de ràtio d’esbocat per a cadascun dels materials en els diferents sentits de esbocat. Com a mètode alternatiu del procés de tall, es realitzen unes mostres amb tall per aigua. S’observarà si els esbocats trenquen o no trenquen i en quines condicions ho fan. Una vegada realitzats aquests assajos, es procedirà a realitzar l’estudi de microdureses amb un indentador Vickers per tal de comprovar l’afectació de l’operació de tall en la microestructura del material. Es realitzarà també algun perfil de dureses utilitzant el Nanoindentador. Per finalitzar el projecte, s’inclourà un apartat de conclusions i un estudi mediambiental produït com a conseqüència de l’elaboració del projecte, així com un pressupost total d’aquest.
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Edició crítica del París e Viana català que té com a testimoni de base l'incunable de Girona de 1495, que es conserva a la Biblioteca Reial de Copenhaguen. El treball conté una anàlisi comparativa de les variants de l'edició de Girona i de les de l'edició de Barcelona. Es desmenteix la hipòtesi de Cátedra (1986: 37-38), segons la qual el Curial e Güelfa podria dependre del París e Viana i s'argumenta la inconveniència de classificar aquesta novel·la cavalleresca com a ficció sentimental. Les notes permeten resseguir els motius literaris comuns que constitueixen el relat
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Sustained atrial fibrillation (AF) is maintained by sites displaying high dominant frequency (DF). In patients (pts) with long-standing persistent AF (LS-pAF), their spatial distribution and the presence of a left-to-right atrial DF gradient remain poorly known. We hypothesized that the pre-ablation bi-atrial frequency characteristics of LS-pAF pts terminated within the left atrium (LT) are different from that of non terminated (NT) ones. Methods: 23 consecutive pts (59±7y, LS-pAF duration 19±12m) underwent stepwise catheter ablation (step-CA) consisting in pulmonary veins isolation, left atrial (LA) defragmentation, and right atrial (RA) ablations for non terminated AF. A quadripolar catheter (CAT) was placed into the RA appendage (RAA), a decapolar CAT into the coronary sinus (CS) and a duodecapolar CAT into the LA divided into 8 segments. For each segment, 20-sec of bipolar recording was acquired. The DF was defined as the largest peak in the power spectrum (3-15 Hz). The inter-atrial DF gradient was defined as the DF difference between LA and RA appendages. Results: LS-pAF was terminated in 83% (19/23) of the pts: 17 LT, 2 during RA ablation and 4 NT. The figure shows that before ablation bi-atrial DF values of LT pts are significantly lower than that of NT pts for each LA segment as well as for the RAA (p < 0.05). No significant LA-to-RA DF gradient was observed both for LT (0.3±0.5 Hz, p=ns) and NT (0.5±0.03 Hz, p=ns) pts. No significant difference in DF values was observed between LA segments. Conclusions: The lower DF of LT pts is suggestive of a higher organization within both atria compared to NT pts. Our findings suggest that low bi-atrial DF values, but not inter-atrial DF gradient, might be of interest for selecting LS-pAF candidates for sinus rhythm restoration by step-CA.
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L'objectiu principal del treball de recerca és el disseny de dos crèdits variables, matèries optatives dins de l'Educació Secundària Obligatòria, entorn de la cultura grega clàssica.
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The application of two approaches for high-throughput, high-resolution X-ray phase contrast tomographic imaging being used at the tomographic microscopy and coherent radiology experiments (TOMCAT) beamline of the SLS is discussed and illustrated. Differential phase contrast (DPC) imaging, using a grating interferometer and a phase-stepping technique, is integrated into the beamline environment at TOMCAT in terms of the fast acquisition and reconstruction of data and the availability to scan samples within an aqueous environment. A second phase contrast method is a modified transfer of intensity approach that can yield the 3D distribution of the decrement of the refractive index of a weakly absorbing object from a single tomographic dataset. The two methods are complementary to one another: the DPC method is characterised by a higher sensitivity and by moderate resolution with larger samples; the modified transfer of intensity approach is particularly suited for small specimens when high resolution (around 1 mu m) is required. Both are being applied to investigations in the biological and materials science fields.
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Proyecto de implantación de un sistema de business intelligence para el análisis de la calidad de un servicio. El objetivo del presente proyecto es el análisis de una herramienta de apoyo al estudio de la calidad de un servicio, en este caso, servicio sanitario, enfocada desde la perspectiva del área de Ingeniería del software.
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In this paper, a phenomenologically motivated magneto-mechanically coupled finite strain elastic framework for simulating the curing process of polymers in the presence of a magnetic load is proposed. This approach is in line with previous works by Hossain and co-workers on finite strain curing modelling framework for the purely mechanical polymer curing (Hossain et al., 2009b). The proposed thermodynamically consistent approach is independent of any particular free energy function that may be used for the fully-cured magneto-sensitive polymer modelling, i.e. any phenomenological or micromechanical-inspired free energy can be inserted into the main modelling framework. For the fabrication of magneto-sensitive polymers, micron-size ferromagnetic particles are mixed with the liquid matrix material in the uncured stage. The particles align in a preferred direction with the application of a magnetic field during the curing process. The polymer curing process is a complex (visco) elastic process that transforms a fluid to a solid with time. Such transformation process is modelled by an appropriate constitutive relation which takes into account the temporal evolution of the material parameters appearing in a particular energy function. For demonstration in this work, a frequently used energy function is chosen, i.e. the classical Mooney-Rivlin free energy enhanced by coupling terms. Several representative numerical examples are demonstrated that prove the capability of our approach to correctly capture common features in polymers undergoing curing processes in the presence of a magneto-mechanical coupled load.
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Freshwater snails belonging to the genus Biomphalaria act as intermediate hosts for the parasite trematode Schistosoma mansoni in Africa and in the neotropical region. Identification of such molluscs is carried out based on morphological characters and the presence of cercariae is verified through squeezing snails between two glass slides or by exposing them to artificial light. However, sometimes, the material collected includes molluscs with decomposed bodies or, yet, only empty shells, which precludes their identification and S. mansoni detection. Due to these difficulties, we have developed a methodology in which DNA may be extracted from traces of organic material from inside shells in order to identify molluscs through polymerase chain reaction and restriction fragment length polymorphism and to detect S. mansoni into these snails, by using low stringency polymerase chain reaction. Species-specific profiles obtained from B. glabrata, B. straminea, and B. tenagophila snails and their shells, maintained in laboratory for ten years, showed the same profiles. S. mansoni profiles showed to be present in shell specimens as far as the eighth week after being removed from aquarium.
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We describe an innovative use of multimedia materials to support training and advocacy within a schistosomiasis control programme. The Schistosomiasis Control Initiative (SCI) at Imperial College London works with selected sub-Saharan African countries to develop schistosomiasis control programmes. Two elements of the SCI programme were supported by multimedia materials developed at the Wellcome Trust in collaboration with the SCI: (1) training of programme managers, district health officers, and those delivering practical elements of the programme; and (2) advocacy targeted at decision-makers and donors. Evaluation of the materials revealed high reported ratings for both user satisfaction and impact from use of the product. From this experience we draw out several general messages about development of multimedia materials and how these will play a growing future role in promoting training within international health.
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El presente documento tiene por objetivo identificar la evolución que ha tenido la inteligencia de negocios en la ultima década, para determinar en que punto se encuentra y para donde va, además de identificar las alternativas de desarrollo que tiene, apalancándose con las Tecnologías de la Información, y más específicamente con las herramientas empaquetadas de BI de tipo Open Source.Así mismo, la presente investigación identifica las prácticas más convenientes, para sistematizar la elección y adaptación de la inteligencia de negocios en las organizaciones, analizando estas en uncaso exitoso real de implantación de la inteligencia de negocios sobre una herramienta BI tipo Open Source.
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Actualmente muchas empresas ya sean grandes o pequeñas, se plantean implantar en su organización un sistema de información que les ayude en la toma de decisiones. Una de las tendencias actuales es implantar un sistema de BI (Business Intelligence). Muchas organizaciones implantan este tipo de sistemas sin haber realizado un estudio previo de las necesidades y problemas de la empresa, de los beneficios que se pretenden obtener con la implantación del sistema, de la aceptación y formación de los usuarios, de las herramientas y proveedores de BI,... y así un largo etcétera de situaciones y condiciones que se deberían tener en cuenta para la implantación de esta clase de sistemas en cualquier tipo de organización, ya sea grande o pequeña.En el presente artículo se realiza una síntesis de la amalgama de información existente en los sistemas de BI, se realiza una definición aclaratoria, así como también se expone su estado actual, beneficios, factores de riesgo, pasos para conseguir una implantación exitosa y los componentes y herramientas open source de los sistemas de BI. Primero se exponen las principales herramientas open source existentes en el mercado y se profundiza más especialmente en la Suite open source de BI Pentaho.
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Initiatives to stimulate the development and propagation of open educational resources (OER) need a sufficiently large community that can be mobilized to participate in this endeavour. Failure to achieve this could lead to underuse of OER. In the context of the Wikiwijs initiative a large scale survey was undertaken amongst primary and secondary school teachers to explore possible determinants of the educational use of digital learning materials (DLMs). Basing on the Integrative Model of Behaviour Prediction it was conjectured that self-efficacy, attitude and perceived norm would take a central role in explaining the intention to use DLMs. Several other predictors were added to the model as well whose effects were hypothesized to be mediated by the three central variables.All conjectured relationships were found using path analysis on survey data from 1484 teachers. Intention to DLMs was most strongly determined by self-efficacy, followed by attitude. ICT proficiency was in its turn the strongest predictor of self-efficacy. Perceived norm played only a limited role in the intention to use DLMs. Concluding, it seems paramount for the success of projects such as Wikiwijs to train teachers in the use of digital learning materials and ICT (e.g. the digital blackboard) and to impact on their attitude.
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En el nostre grup d’investigació i en col·laboració amb el grup d’investigació del doctor Daniel Ruiz-Molina del Centre d’investigació en Nanociència i Nanotecnologia (CIN2) d’aquest campus universitari, hem iniciat un projecte que es planteja aconseguir biomimetitzar certes proteïnes adhesives de mol·luscs, en que la seva adherència es deu a la presència de la funcionalitat catecol. Aprofitant aquesta propietat adhesiva dels catecols, l’objectiu és poder desenvolupar nous materials per a recobriments hidro- i oleofòbics, i nous materials adhesius sent necessari el desenvolupament de protocols sintètics per a l’obtenció de compostos tipus catecol convenientment substituïts. En el present treball de recerca s’ha aconseguit la síntesi del nou catecol 10, que presenta en la seva estructura una cadena alquílica parcialment fluorada amb la finalitat de fer-ne recobriments hidro- i oleofòbics, i l’optimització i escalat del catecol 2, que presenta una cadena alquílica, amb la finalitat de fer-ne recobriments hidrofòbics. També s’ha explorat en la síntesi de catecols amb una funcionalitat tiol amb la finalitat de poder desenvolupar superfícies o nanopartícules d’or adhesives. Partint del producte comercial 17, s’ha aconseguit obtenir 10 en tres etapes sintètiques i un rendiment global del 57% i 2 en dues etapes sintètiques i un rendiment global del 63% a escala multigram, millorant la metodologia sintètica existent que consistia en quatre etapes sintètiques i un 48% de rendiment global.