Técnicas y métodos más adecuados para la identificación del cemento aluminoso y de cemento de base portland en hormigones

Instrumental techniques are indicated and the most adequated methodologies for determining the nature of the binder in concretes are explained. These methods are: a) Determination of the Silicic Moduli through chemical analysis of the sample. This test reveáis very different valúes between cement portland based concrete and high alumina cement based concretes. b) X-ray diffraction. It is considered as the best method. In the present paper the main diffraction Unes corresponding to the components of hydrated portland cement and high alumina cement, are given. As complementary methods having as limited use, DTA and TG are studied. The most significative changes of the hydrated phases of both cements when heated are shown. A valoration of the Oxine test is also done as well as a description of using the characteristic colour of the high alumina cement as a practical indicator for determining its presence in concretes. Finally, comments on the significance of the presence of different CaCO3 polymorhisms in portland cement concrete and high alumina cement concrétete are also done.Se indican las técnicas y se explican las metodologías más adecuadas para determinar la naturaleza del conglomerante aluminoso en hormigones. Estos métodos son: a) Determinación del Módulo Silícico, a través de Análisis Químico de la muestra problema, al considerar la acusada diferencia de aquel valor en hormigones de cemento portland, respecto a hormigones de cemento aluminoso. b) Difracción de Rayos X. Se considera la técnica idónea. Se dan en el presente trabajo las principales líneas de difracción de los compuestos característicos de los cementos hidratados, portland y aluminoso. Como métodos complementarios y de utilidad limitada se estudia el ATD y el TG. Se proponen las temperaturas más significativas de los compuestos hidratados de aquellos cementos, a través de lo cual se puede deducir la presencia de uno u otro tipo de cemento. Se hace una valoración del método de la "oxina", significando el alcance limitado del mismo. Igualmente se describe el color como indicador de gran interés práctico en la determinación del cemento aluminoso. Así como un comentario documentado sobre el significado de la presencia de diferentes polimorfías del CaCO3 en los hormigones de cemento portland y de cemento aluminoso

Mineralogía y ceramicidad de las arcillas del yacimiento de Sitjar, Onda (Castellón)

Este trabajo tiene por objeto la caracterización mineralógica y físico-química de las arcillas terciarias explotadas en el yacimiento de Sitjar, cercano a la localidad de Onda (Castellón), utilizadas comomateria prima por la industria ceramica castellonense. Se estudian también algunas propiedades ceramicas de estas arcillas, incidiendo en el comportamiento térmico, para su correcta aplicación. a composición química y mineralógica posibilita su utilización como aditivo para la fabricaci6n de materiales porosos y refractarios

Designing Future Ships for Significantly Lower Energy Consumption

The likelihood of both increases in, and volatility of, the cost of conventional fuel in the coming decades combined with more stringent emission regulations, means that ships in the future will have to be significantly more efficient and make use of alternative sources of energy. Considering the regulatory aspect, it has been claimed that, if the IMO were to reduce international shipping’s carbon dioxide emissions to those consistent with limiting anthropogenic climate change to 2 degrees of warming, then ships in 2050 would have to reduce their carbon dioxide emissions by 75-90% compared to ships in 2012. To investigate what might be the appropriate mix of technologies and operational approaches for future ship designs the “Whole Ship Model” (WSM) was developed, which is a holistic ship design tool, primarily developed at UCL, that can generate many ship design options with different design, technology and fuel combinations. The Whole Ship model can be used to explore different arrangements and uses of energy efficiency measures on container ships, bulk carriers and tankers evaluating their performance over an operating profile. This paper will initially present some results from the Whole Ship Model, evaluating the potential performance of present-day ships and technologies and will then compare this to technically feasible future ship designs that use contemporary or near-term technology to achieve very high reductions in carbon dioxide emissions and energy consumption

Objective assessment of gender differences in learning strategies

La Teoría de Metas de Logro señala la existencia de estas dos estrategias u orientaciones motivacionales: la orientación de resultado y la orientación de aprendizaje. La primera suele asociarse a la búsqueda del resultado exitoso e inmediato y la segunda a la comprensión profunda y largo mayor plazo de las diversas implicaciones de una tarea. Algunos estudios señalan que los varones, en comparación con las mujeres, tienden a desarrollar en mayor medida la orientación de resultado. El Test de Aprendizaje de Categorías (TAC), una prueba de atención y aprendizaje, permite discriminar estas dos modalidades de afrontamiento de la tarea. Para investigar las diferencias de género en estas orientaciones, se evaluó a 502 escolares de 6 a 12 años mediante el TAC. Los resultados confirman la existencia de ambos perfiles, aunque no aparecen diferencias de género. Se plantea que quizás estas diferencias surjan más adelante en la evolución debido al aprendizaje y la socialización. La enseñanza de patrones motivacionales adaptativos a largo plazo puede resultar muy beneficiosa para los niños en edad escolar.Goal Theory indicates the existence of two learning strategies and motivational goals: the performance-focused goals and learning-focused goals. The first one is usually associated with the aim of achieving immediate and good results while the second one is associates with deep and long-range comprehension. Some studies show that men, compared with women, tend to develop performance performance-focused goals. The Categories Learning Test (CLT), a test of attention and learning, discriminates these two patterns in children when solving a task. We evaluated 502 schoolchildren of 6-12 years by CLT. The results confirm the existence of both profiles, although not shown gender differences. It argues that these differences may arise later in development due to learning and socialization. Teaching adaptive goals and strategies can be very beneficial for school children

Mapping kinematic functional abilities of the hand to three dimensional shapes for inclusive design

Loss of hand function can have adverse effects on an individual\u27s ability to maintain independence. The ability to perform daily activities, such as food preparation and medication delivery, is dependent on the hand\u27s ability to grasp and manipulate objects. Therefore, the goal of this research was to demonstrate that three dimensional (3D) modeling of hand function can be used to improve the accessibility of handheld objects for individuals with reduced functionality through informed design. Individual models of hand functionality were created for 43 participants and group models were developed for groups of individuals without (Healthy) and with reduced functionality due to arthritis (RFA) of the hand. Cylindrical models representative of auto-injectors of varying diameters were analyzed in 3D space relative to hand function. The individual model mappings showed the cylinder diameter with the highest mapped functional values varied depending on the type of functional weighting chosen: kinematic redundancy of fingertip pad positional placement, fingertip pad orientation, or finger force directionality. The group mappings showed that for a cylinder to be grasped in a power grasp by at least 75% of the Healthy or RFA groups, a diameter of 40 mm was required. This research utilizes a new hand model to objectively compare design parameters across three different kinematic factors of hand function and across groups with different functional abilities. The ability to conduct these comparisons enables the creation of designs that are universal to all – including accommodation of individuals with limits in their functional abilities

Integrated supply of stemwood and residual biomass to forest-based biorefineries

The demand for forest biomass as raw material for a wide range of products in the developing bioeconomy is expected to increase. Along with a constant pressure on forestry to increase its productivity, this development has led to the search for new procurement methods and new assortments. The present study assessed innovative supply chain practices, with a particular focus on the integrated supply of stemwood and residual tree parts. The assortments considered included tree sections, long tops, saw logs with stump cores and small whole trees from thinnings. The assessment included geographically explicit modelling of the supply chain operations and estimation of supply cost and energy use for three industrial locations in Northern Sweden. The innovative supply chains were compared to conventional, separate, harvest of stemwood and logging residues. We conclude that integrated harvest of tops and branches with stemwood assortments, as well as whole-tree harvest in early thinnings, has a significant potential to reduce the supply cost for the non-stemwood assortments. Stump wood generally remains the most expensive assortment. The energy use analysis confirms earlier research showing that the energy input is relatively small compared to the energy content of the harvested feedstock