309 research outputs found
Waste and Recycled Textiles as Reinforcements of Building Materials
Currently, the use of composite materials in the construction areas has had a great impact on the society; mainly, those related with sustainability and environment aspects. Daily proposals aimed at overcoming the properties of traditional materials that arise, which include emergent materials either from waste or recycled products. One of them is related to the textile materials, which include fibers such as wool, hemp, linen, and cotton. In the past decade, special attention has been focused on the used clothes, which represent a source of raw materials environmentally responsible and economically profitable. Textile materials are discarded daily around the world, representing approximately 1.5% of the generated waste. Blue jeans are the most used clothing in the world, and they are elaborated by one of the most commonly used natural textile fibers—cotton. Textile materials have been reused in different applications, for example, in the production of poor-quality wires, crushed to manufacture noise and temperature insulation materials, and as fillers or reinforcements of concrete. In this chapter, different topics are described that include: (a) environmental impact of textile waste—a result of massive consumption of clothing, (b) recycling and reuse of textile waste, and (c) waste and recycled textile materials used as building materials
Las apropiaciones de la ciudad a la hora de la globalización: las estrategias del capital ruso y chino en el mercado inmobiliario de Barcelona
[spa]Con la internacionalización del mercado inmobiliario de las ciudades, originariamente local, se han generado nuevos flujos de capital que han reforzado a nivel mundial el segundo circuito. Barcelona, por lo menos desde 1992 no ha sido ajena a ello. Los últimos capitales llegados proceden de antiguos países socialistas, especialmente de la República Popular de China y de Rusia, con estrategias distintas de localización, más concentradas las chinas. Las consecuencias de estas nuevas apropiaciones del espacio urbano se sienten en la restricción del acceso al mercado de la vivienda por parte de los ciudadanos y en la formación de una Chinatown de modelo europeo.[eng]With the internationalization of the urban real estate market, originally local, have generated new capital flows worldwide that have reinforced the second circuit. Barcelona, at least since 1992 has not been immune to it. The latest arrivals come from former socialist countries, especially from the People's Republic of China and Russia, with more concentrated Chinese different localization strategies. The consequences of these new appropriations of urban space are restricting access to the housing market to the citizens and the formation of a European model of Chinatown
Efficient structural shape optimization: using directional high order sensitivity analysis to improve MP algorithms
6th US National Congress on Computational Mechanics, Dearborn,
US
An efficient MP algorithm for structural shape optimization problems
6th International Conference on Computer Aided Optimun Design of Structures, 2001, Bologna[Abstract] Integral methods -such as the Finite Element Method (FEM) and the Boundary Element Method (BEM)- are frequently used in structural optimization problems to solve systems of partial differential equations. Therefore, one must take into account the large computational requirements of these sophisticated techniques at the time of choosing a suitable Mathematical Programming (MP) algorithm for this kind of problems. Among the currently avaliable MP algorithms, Sequential Linear Programming (SLP) seems to be one of the most adequate to structural optimization. Basically, SLP consist in constructing succesive linear approximations to the original non linear optimization problem within each step. However, the application of SLP may involve important malfunctions. Thus, the solution to the approximated linear problems can fail to exist, or may lead to the highly unfeasible point of the original non linear problem; also, large oscillations often occurs near the optimum, precluding the algorithm to converge.
In this paper, we present an improved SLP algorithm with line-search, specially designed for structural optimization problems. In each iteration, an approximated linear problem with aditional side constraints is solved by Linear Programming. The solution to the linear problem defines a search direction. Then, the objetive function and the non linear constraints are quadratically approximated in the search direction, and a line-search in perfomed. The algorithm includes strategies to avoid stalling in the boundary of the feasible region, and to obtain alternate search directions in the case of incompatible linearized constraints. Techniques developed by the authors for efficient high-order shape sensitivity analysis are referenced.Ministerio de Economía y Competitividad; TIC-98-0290Xunta de Galicia; PGIDT99MAR1180
InstanceCollage: a tool for the particularization of collaborative IMS-LD scripts
Current research work in e-learning and more specifically in the field of CSCL (Computer Supported Collaborative Learning) deals with design of collaborative activities, according to computer-interpretable specifications, such as IMS Learning Design, and their posterior enactment using LMSs (Learning Management Systems). A script that describes such collaborative activities is typically designed beforehand in order to structure collaboration, and defines the features that determine the behavior of the LMS, for instance, the sequence of activities or the groups/role distribution. In CSCL settings, group management and composition are especially relevant and affect the chances of achieving the expected learning outcomes. This paper presents a software tool, named InstanceCollage, which aims at facilitating the configuration and population of groups for IMS-LD scripts created with the authoring tool Collage, and discusses the implications of the IMS-LD specification with respect to this task. InstanceCollage is designed to process collaboration scripts based on CLFPs (Collaborative Learning Flow Patterns). Using this type of patterns, InstanceCollage focuses on the importance of understanding the function of groups within the learning strategy of the script. This paper describes the approach taken in InstanceCollage to facilitate this understanding for non-expert users. Additionally, two case studies are presented, which represent complex authentic collaborative learning scenarios, as a proof of concept of the functionality of this tool. The case studies are also used to illustrate the requirements of group configuration tools and to show that InstanceCollage complies to such requirements
Urban space appropriations on the globalization: strategies of Chinese and Russian capital in the real estate market in Barcelona
Con la internacionalización del mercado inmobiliario de las ciudades, originariamente local, se han generado nuevos flujos de capital que han reforzado a nivel mundial el segundo circuito. Barcelona, por lo menos desde 1992 no ha sido ajena a ello. Los últimos capitales llegados proceden de antiguos países socialistas, especialmente de la República Popular de China y de Rusia, con estrategias distintas de localización, más concentradas las chinas. Las consecuencias de estas nuevas apropiaciones del espacio urbano se sienten en la restricción del acceso al mercado de la vivienda por parte de los ciudadanos y en la formación de una Chinatown de modelo europeo.With the internationalization of the urban real estate market, originally local, have generated new capital flows worldwide that have reinforced the second circuit. Barcelona, at least since 1992 has not been immune to it. The latest arrivals come from former socialist countries, especially from the People's Republic of China and Russia, with more concentrated Chinese different localization strategies. The consequences of these new appropriations of urban space are restricting access to the housing market to the citizens and the formation of a European model of Chinatown
Colorectal cancer screening programme in Spain: results of key performance indicators after five rounds (2000-2012)
A l'article en PDF consta com a vol. 5Effective quality assurance is essential in any screening programme. This article provides a unique insight into key quality indicators of five rounds of the first population-based colorectal cancer screening programme implemented in Spain (2000-2012), providing the results according to the type of screening (prevalent or first screen and incident or subsequent screen) and test (guaiac or immunochemical). The total crude participation rate increased from 17.2% (11,011) in the first round to 35.9% (22,988) in the last one. Rescreening rate was very high (88.6% in the fifth round). Positivity rate was superior with the faecal immunochemical test (6.2%) than with the guaiac-based test (0.7%) (p< 0.0001) and detection rates were also better with the immunochemical test. The most significant rise in detection rate was observed for high risk adenoma in men (45.5 per 1,000 screened). Most cancers were diagnosed at an early stage (61.4%) and there was a statistically significant difference between those detected in first or subsequent screening (52.6% and 70.0% respectively; p= 0.024). The availability of these results substantially improves data comparisons and the exchange of experience between screening programmes
Análisis descriptivo de la respuesta cardíaca a tres protocolos de entrenamiento con cargas
Objetivo. El Objetivo del estudio fue observar si existían diferencias significativas en tres protocolos de entrenamiento con cargas, en su respuesta cardiodinámica. Material y métodos. 15 hombres y 14 mujeres realizaron tres protocolos diferentes de entrenamiento en circuito, circuito de peso libre (CPL), entrenamiento en máquinas (CM) y mixto aeróbico (peso libre y ejercicio aeróbico)(CMA), conectados a un analizador de gases portátil Jaeger Oxycon Mobile (Erich Jaeger, Viasys Healthcare, Alemania), que además registra la frecuencia cardíaca a través de un sensor de Polar® heart rate monitor (Polar Electro, Kempele, Finland). Se calculó la carga máxima para 15 RM y se realizó una prueba de esfuerzo máximo, con el objetivo de utilizar el mismo volumen e intensidad en los tres protocolos. Resultados. Existen diferencias significativas entre hombres y mujeres, sobre todo entre los circuitos CM con el resto, CPL y CMA, que producen una mayor exigencia cardíaca. La respuesta cardíaca muestra una respuesta significativamente mayor en el CPL y el CMA con respecto a CM en ambos sexos, que coincide con la respuesta en el consumo de oxígeno. En ninguno los protocolos se consigue llegar a los estándares del ACSM, salvo en el CMA, para el entrenamiento aeróbico (50% del VO2 máx.). Discusión y conclusiones. La mayor implicación muscular y las necesidades aumentadas de control postural en ejercicios con peso libre podrían explicar estas diferencias. Existen diferencias significativas en la respuesta cardíaca en tres tipos de circuitos de iguales duraciones e intensidades. Además, tan solo el circuito CMA produciría un aumento el consumo de oxígeno significativo
Evaluación de dos estrategias de cribado de cáncer colorrectal: Test inmunológico versus test bioquímico. Cataluña, 2008-2010
Fundamento: El objetivo del estudio fue evaluar el cambio de estrategia de cribado (test inmunológico cuantitativo) en un programa poblacional de detección precoz de cáncer colorrectal (CCR) en Cataluña. Métodos: La cuarta ronda del programa de cribado de CCR en Hospitalet de Llobregat se implementó en 2008-2010. Se ofreció un test bioquímico a 50.227 individuos y uno inmunológico cuantitativo a 12.707 individuos. Se analizaron diferencias en las dos estrategias de cribado respecto a variables de aceptabilidad (entre participación, abandonos y adherencia a la colonoscopia), de precisión diagnóstica (valor predictivo positivo y tasas de detección), de resultados (tamaño y localización de lesiones, estadio de los cánceres detectados) y de recursos (número necesario de colonoscopias e intervalo de tiempo entre el resultado positivo del test y la colonoscopia). Resultados: La participación en el cribado fue superior entre los individuos que utilizaron el test inmunológico (OR: 1,35; IC95%:1,27-1,42). Las tasas de detección fueron superiores para el test inmunológico destacando la de adenomas de alto riesgo (26,7 vs 3,0 ). El valor predictivo positivo para adenomas de alto riesgo fue del 45,0% y del 46,9% en el inmunológico y el guayaco, respectivamente. El número de colonoscopias necesarias para detectar un cáncer fue de casi el doble que en el guayaco (13,6 vs 7,4). Conclusiones: El test inmunológico es una buena estrategia de cribado especialmente sensible para la detección de adenomas de alto riesgo. Sin embargo, requiere realizar un gran número de colonoscopias y por ello se debe disponer de los recursos y medios necesarios
- …