39 resultados para Technological improvements

em Universidad Politécnica de Madrid


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Infrared thermography IR is a technique, which allows us to get rapidly and non-invasive thermal images from objects or human beings. (Barnes, 1967). In Medicine, its usefulness as diagnosis tool was accepted decades ago (BenEliyahu, 1990), but other techniques with a higher efficiency -such as magnetic resonance or x-rays- ousted it. Nevertheless, the technological improvements on thermographic cameras and new studies on sport injuries are reinforcing new applications (Ring, 2006)

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The principle of complexity as the evolution vector of the gothic style was an idea largely developed by Paul Frankl. The high complexity reached in the 15th and 16th centuries was possible thanks to the geometrical resources developed in the workshops of the medieval stonemasons. The search for more sophisticated designs was possible also with the higher standardization, so that the most complex ribbed vault could be built with ribs that had all the same curvature and with voussoirs that were therefore identical. Spanish Gothic architecture has been deeply studied from a historical and artistic point of view. The present paper, as a complement to these analyses, aims to point out some of the geometrical methods and technological improvements that late medieval masons were able to develop. In that way, some selected vaults have been measured, in order to study their geometry and design process. Also scale models of some vaults have been built at the Escuela de Arquitectura (Madrid) to validate these geometrical principles. More than just a research method, the scale models allow to understand the medieval construction techniques, and they are a powerful pedagogical tool with which pupils can reach a rewarding experience based on the “medieval-way” praxis.

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The author participated in the 6 th EU Framework Project ―Q-pork Chains (FP6-036245-2)‖ from 2007 to 2009. With understanding of work reports from China and other countries, it is found that compared with other countries, China has great problems in pork quality and safety. By comparing the pork chain management between China and Spain, It is found that the difference in governance structure is one of the main differences in pork chain management between Spain and China. In China, spot-market relationship still dominates governance structure of pork chain, especially between the numerous house-hold pig holders and the great number of small slaughters. While in Spain, chain agents commonly apply cooperatives or integrations to cooperate. It also has been proven by recent studies, that in quality management at the chain level that supply chain integration has a direct effect on quality management practices (Han, 2010). Therefore, the author started to investigate the governance structure choices in supply chain management. And it has been set as the first research objective, which is to explain the governance structure choices process and the influencing factors in supply chain management, analyzing the pork chains cases in Spain and in China. During the further investigation, the author noticed the international trade of pork between Spain and China is not smooth since the signature of bi-lateral agreement on pork trade in 2007. Thus, another objective of the research is to find and solve the problems exist in the international pork chain between Spain and China. For the first objective, to explain the governance structure choices in supply chain management, the thesis conducts research in three main sections. 10 First of all, the thesis gives a literature overview in chapter two on Supply Chain Management (SCM), agri-food chain management and pork chain management. It concludes that SCM is a systems approach to view the supply chains as a whole, and to manage the total flow of goods inventory from the supplier to the ultimate customer. It includes the bi-directional flow of products (materials and services) and information, and the associated managerial and operational activities. And it also is a customer focus to create unique and individual source of customer value with an appropriate use of resources, leading to customer satisfaction and building competitive chain advantages. Agri-food chain management and pork chain management are applications of SCM in agri-food sector and pork sector respectively. Then, the research gives a comparative study in chapter three in the pork chain and pork chain management between Spain and China. Many differences are found, while the main difference is governance structure in pork chain management. Furthermore, the author gives an empirical study on governance structure choice in chapter five. It is concluded that governance structure of supply chain consists of a collection of rules/institutions/constraints structuring the transactions between the various stakeholders. Based on the overview on literatures closely related with governance structure, such as transaction cost economics, transaction value analysis and resource-based view theories, seven hypotheses are proposed, which are: Hypothesis 1: Transaction cost has positive relationship with governance structure choice Hypothesis 2: Uncertainty has positive relationship with transaction cost; higher uncertainty exerts high transaction cost Hypothesis 3: The relationship between asset specificity and transaction cost is positive Hypothesis 4: Collaboration advantages and governance structure choice have positive relationship11 Hypothesis 5: Willingness to collaborate has positive relationship with collaboration advantages Hypothesis 6: Capability to collaborate has positive relationship with collaboration advantages Hypothesis 7: Uncertainty has negative effect on collaboration advantages It is noted that as transaction cost value is negative, the transaction cost mentioned in the hypotheses is its absolute value. To test the seven hypotheses, Structural Equation Model (SEM) is applied and data collected from 350 pork slaughtering and processing companies in Jiangsu, Shandong and Henan Provinces in China is used. Based on the empirical SEM model and its results, the seven hypotheses are proved. The author generates several conclusions accordingly. It is found that the governance structure choice of the chain not only depends on transaction cost, it also depends on collaboration advantages. Exchange partners establish more stable and more intense relationship to reduce transaction cost and to maximize collaboration advantages. ―Collaboration advantages‖ in this thesis is defined as the joint value achieved through transaction (mutual activities) of agents in supply chains. This value forms as improvements, mainly in mutual logistics systems, cash response, information exchange, technological improvements and innovative improvements and quality management improvements, etc. Governance structure choice is jointly decided by transaction cost and collaboration advantages. Chain agents take different governance structures to coordinate in order to decrease their transaction cost and to increase their collaboration advantages. In China´s pork chain case, spot market relationship dominates the governance structure among the numerous backyard pig farmer and small family slaughterhouse 12 as they are connected by acquaintance relationship and the transaction cost in turn is low. Their relationship is reliable as they know each other in the neighborhood; as a result, spot market relationship is suitable for their exchange. However, the transaction between large-scale slaughtering and processing industries and small-scale pig producers is becoming difficult. The information hold back behavior and hold-up behavior of small-scale pig producers increase transaction cost between them and large-scale slaughtering and processing industries. Thus, through the more intense and stable relationship between processing industries and pig producers, processing industries reduce the transaction cost and improve the collaboration advantages with their chain partners, in which quality and safety collaboration advantages be increased, meaning that processing industries are able to provide consumers products with better quality and higher safety. It is also drawn that transaction cost is influenced mainly by uncertainty and asset specificity, which is in line with new institutional economics theories developed by Williamson O. E. In China´s pork chain case, behavioral uncertainty is created by the hold-up behaviors of great numbers of small pig producers, while big slaughtering and processing industries having strong asset specificity. On the other hand, ―collaboration advantages‖ is influenced by chain agents´ willingness to collaborate and chain agents´ capabilities to cooperate. With the fast growth of big scale slaughtering and processing industries, they are more willing to know and make effort to cooperate with their chain members, and they are more capable to create joint value together with other chain agents. Therefore, they are now the main chain agents who drive more intense and stable governance structure in China‘s pork chain. For the other objective, to find and solve the problems in the international pork chain between Spain and China, the research gives an analysis in chapter four on the 13 international pork chain. This study gives explanations why the international trade of pork between Spain and China is not sufficient from the chain perspective. It is found that the first obstacle is the high quality and safety requirement set by Chinese government. It makes the Spanish companies difficult to get authorities to export. Other aspects, such as Spanish pork is not competitive in price compared with other countries such as Denmark, United States, Canada, etc., Chinese consumers do not have sufficient information on Spanish pork products, are also important reasons that Spain does not export great quantity of pork products to China. It is concluded that China´s government has too much concern on the quality and safety requirements to Spanish pork products, which makes trade difficult to complete. The two countries need to establish a more stable and intense trade relationship. They also should make the information exchange sufficient and efficient and try to break trade barriers. Spanish companies should consider proper price strategies to win the Chinese pork market

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La tesis doctoral “Mejoras Tecnológicas en el Reciclado de Residuos de Construcción y Demolición (RCD)” investiga la utilización de los separadores hidráulicos para mejorar la calidad de los áridos reciclados, y se demuestra que es un equipo más eficiente que las técnicas actuales basadas en la simple separación por densidad. En la tesisn se ha realizado inicialmente una revisión de la situación del sector, para a continuación centrarse en los sistemas de separación utilizados en las plantas de valorización españolas. Una vez analizados éstos y en particular los de tipo hidráulico, de los que se resume un estudio comparativo, se ha procedido a ensayar a escala de Laboratorio el comportamiento de un separador hidráulico de aceleración diferencial con diversos materiales procedentes de tres plantas de reciclaje. Adicionalmente fueron probadas otras técnicas, como es la separación magnética para mejorar la calidad de los productos reciclados. En vista de los buenos resultados de la investigación, se procede a escalar los ensayos con equipo piloto y distintas composiciones de naturaleza cerámica y hormigón. El equipo utilizado fue un jig de 3´x 1´ en el que se ensayaron las tres muestras con resultados diferentes. La limpieza de los materiales impropios y el yeso fue positiva en las tres muestras, y únicamente la separación entre sí de los componentes pétreos, resultó dependiente de su proporción en la mezcla, obteniéndose los mejores resultados en las muestras con menor cantidad de materiales cerámicos. Finalmente, se procede a analizar en un laboratorio reconocido las propiedades de los áridos reciclados obtenidos en la separación hidráulica por jig, y constatar las mejoras conseguidas para su utilización como materiales de construcción en usos ligados y no ligados. Todo lo anterior permite afirmar que los equipos de separación hidráulica con aceleración diferencial (jig) presentan una innovación tecnológica en el reciclado de los residuos de construcción y demolición (RCD). ABSTRACT The doctoral thesis “Technological Improvements in Recycling of Construction and Demolition Waste (C&DW)” researches the hydraulic separators utilization in order to improve the recycled aggregates quality, demonstrating that the equipment is more efficient than the current techniques based on the simple density separation. This doctoral thesis has been initially done reviewing the situation of the sector and focusing afterwards on the separation systems used at the Spanish recovery facilities. Once analyzed these and, particularly, the hydraulic type ones, from which a comparative study has been summarized, the behavior of a differential acceleration hydraulic separator with various materials coming from three recycling plants has been tested at laboratory scale. Additionally other techniques have been tested, such as the magnetic separation to improve the quality of recycled products. In view of the good investigation results, the testing process scaled up by using pilot equipment and different ceramics and concrete compositions. The equipment utilized was a jig 3” x 1”, in which the three samples were tested with different results. The unsuitable materials and gypsum cleanliness was positive on the three samples and only the separation among the stony components turned out to be dependent of its proportion in the mixing, obtaining the best results in the samples with less quantity of ceramic materials. Finally, the properties of the recycled aggregates obtained by jig hydraulic separation are analyzed at a recognized laboratory and the improvements gained for their utilization as construction materials, in bounded and unbounded uses, are stated. The facts cited are a basis for affirming that the hydraulic separator equipments with differential acceleration (jig) offer a technological innovation in the Recycling of Construction and Demolition Waste (C&DW).

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La termografía infrarroja (TI) es una técnica no invasiva y de bajo coste que permite, con el simple acto de tomar una fotografía, el registro sin contacto de la energía que irradia el cuerpo humano (Akimov & Son’kin, 2011, Merla et al., 2005, Ng et al., 2009, Costello et al., 2012, Hildebrandt et al., 2010). Esta técnica comenzó a utilizarse en el ámbito médico en los años 60, pero debido a los malos resultados como herramienta diagnóstica y la falta de protocolos estandarizados (Head & Elliot, 2002), ésta se dejó de utilizar en detrimento de otras técnicas más precisas a nivel diagnóstico. No obstante, las mejoras tecnológicas de la TI en los últimos años han hecho posible un resurgimiento de la misma (Jiang et al., 2005, Vainer et al., 2005, Cheng et al., 2009, Spalding et al., 2011, Skala et al., 2012), abriendo el camino a nuevas aplicaciones no sólo centradas en el uso diagnóstico. Entre las nuevas aplicaciones, destacamos las que se desarrollan en el ámbito de la actividad física y el deporte, donde recientemente se ha demostrado que los nuevos avances con imágenes de alta resolución pueden proporcionar información muy interesante sobre el complejo sistema de termorregulación humana (Hildebrandt et al., 2010). Entre las nuevas aplicaciones destacan: la cuantificación de la asimilación de la carga de trabajo físico (Čoh & Širok, 2007), la valoración de la condición física (Chudecka et al., 2010, 2012, Akimov et al., 2009, 2011, Merla et al., 2010), la prevención y seguimiento de lesiones (Hildebrandt et al., 2010, 2012, Badža et al., 2012, Gómez Carmona, 2012) e incluso la detección de agujetas (Al-Nakhli et al., 2012). Bajo estas circunstancias, se acusa cada vez más la necesidad de ampliar el conocimiento sobre los factores que influyen en la aplicación de la TI en los seres humanos, así como la descripción de la respuesta de la temperatura de la piel (TP) en condiciones normales, y bajo la influencia de los diferentes tipos de ejercicio. Por consiguiente, este estudio presenta en una primera parte una revisión bibliográfica sobre los factores que afectan al uso de la TI en los seres humanos y una propuesta de clasificación de los mismos. Hemos analizado la fiabilidad del software Termotracker, así como su reproducibilidad de la temperatura de la piel en sujetos jóvenes, sanos y con normopeso. Finalmente, se analizó la respuesta térmica de la piel antes de un entrenamiento de resistencia, velocidad y fuerza, inmediatamente después y durante un período de recuperación de 8 horas. En cuanto a la revisión bibliográfica, hemos propuesto una clasificación para organizar los factores en tres grupos principales: los factores ambientales, individuales y técnicos. El análisis y descripción de estas influencias deben representar la base de nuevas investigaciones con el fin de utilizar la TI en las mejores condiciones. En cuanto a la reproducibilidad, los resultados mostraron valores excelentes para imágenes consecutivas, aunque la reproducibilidad de la TP disminuyó ligeramente con imágenes separadas por 24 horas, sobre todo en las zonas con valores más fríos (es decir, zonas distales y articulaciones). Las asimetrías térmicas (que normalmente se utilizan para seguir la evolución de zonas sobrecargadas o lesionadas) también mostraron excelentes resultados pero, en este caso, con mejores valores para las articulaciones y el zonas centrales (es decir, rodillas, tobillos, dorsales y pectorales) que las Zonas de Interés (ZDI) con valores medios más calientes (como los muslos e isquiotibiales). Los resultados de fiabilidad del software Termotracker fueron excelentes en todas las condiciones y parámetros. En el caso del estudio sobre los efectos de los entrenamientos de la velocidad resistencia y fuerza en la TP, los resultados muestran respuestas específicas según el tipo de entrenamiento, zona de interés, el momento de la evaluación y la función de las zonas analizadas. Los resultados mostraron que la mayoría de las ZDI musculares se mantuvieron significativamente más calientes 8 horas después del entrenamiento, lo que indica que el efecto del ejercicio sobre la TP perdura por lo menos 8 horas en la mayoría de zonas analizadas. La TI podría ser útil para cuantificar la asimilación y recuperación física después de una carga física de trabajo. Estos resultados podrían ser muy útiles para entender mejor el complejo sistema de termorregulación humano, y por lo tanto, para utilizar la TI de una manera más objetiva, precisa y profesional con visos a mejorar las nuevas aplicaciones termográficas en el sector de la actividad física y el deporte Infrared Thermography (IRT) is a safe, non-invasive and low-cost technique that allows the rapid and non-contact recording of the irradiated energy released from the body (Akimov & Son’kin, 2011; Merla et al., 2005; Ng et al., 2009; Costello et al., 2012; Hildebrandt et al., 2010). It has been used since the early 1960’s, but due to poor results as diagnostic tool and a lack of methodological standards and quality assurance (Head et al., 2002), it was rejected from the medical field. Nevertheless, the technological improvements of IRT in the last years have made possible a resurgence of this technique (Jiang et al., 2005; Vainer et al., 2005; Cheng et al., 2009; Spalding et al., 2011; Skala et al., 2012), paving the way to new applications not only focused on the diagnose usages. Among the new applications, we highlighted those in physical activity and sport fields, where it has been recently proven that a high resolution thermal images can provide us with interesting information about the complex thermoregulation system of the body (Hildebrandt et al., 2010), information than can be used as: training workload quantification (Čoh & Širok, 2007), fitness and performance conditions (Chudecka et al., 2010, 2012; Akimov et al., 2009, 2011; Merla et al., 2010; Arfaoui et al., 2012), prevention and monitoring of injuries (Hildebrandt et al., 2010, 2012; Badža et al., 2012, Gómez Carmona, 2012) and even detection of Delayed Onset Muscle Soreness – DOMS- (Al-Nakhli et al., 2012). Under this context, there is a relevant necessity to broaden the knowledge about factors influencing the application of IRT on humans, and to better explore and describe the thermal response of Skin Temperature (Tsk) in normal conditions, and under the influence of different types of exercise. Consequently, this study presents a literature review about factors affecting the application of IRT on human beings and a classification proposal about them. We analysed the reliability of the software Termotracker®, and also its reproducibility of Tsk on young, healthy and normal weight subjects. Finally, we examined the Tsk thermal response before an endurance, speed and strength training, immediately after and during an 8-hour recovery period. Concerning the literature review, we proposed a classification to organise the factors into three main groups: environmental, individual and technical factors. Thus, better exploring and describing these influence factors should represent the basis of further investigations in order to use IRT in the best and optimal conditions to improve its accuracy and results. Regarding the reproducibility results, the outcomes showed excellent values for consecutive images, but the reproducibility of Tsk slightly decreased with time, above all in the colder Regions of Interest (ROI) (i.e. distal and joint areas). The side-to-side differences (ΔT) (normally used to follow the evolution of some injured or overloaded ROI) also showed highly accurate results, but in this case with better values for joints and central ROI (i.e. Knee, Ankles, Dorsal and Pectoral) than the hottest muscle ROI (as Thigh or Hamstrings). The reliability results of the IRT software Termotracker® were excellent in all conditions and parameters. In the part of the study about the effects on Tsk of aerobic, speed and strength training, the results of Tsk demonstrated specific responses depending on the type of training, ROI, moment of the assessment and the function of the considered ROI. The results showed that most of muscular ROI maintained warmer significant Tsk 8 hours after the training, indicating that the effect of exercise on Tsk last at least 8 hours in most of ROI, as well as IRT could help to quantify the recovery status of the athlete as workload assimilation indicator. Those results could be very useful to better understand the complex skin thermoregulation behaviour, and therefore, to use IRT in a more objective, accurate and professional way to improve the new IRT applications for the physical activity and sport sector.

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The installers and owners show a growing interest in the follow-up of the performance of their photovoltaic (PV) systems. The owners are requesting reliable sources of information to ensure that their system is functioning properly, and the installers are actively looking for efficient ways of providing them the most useful possible information from the data available. Policy makers are becoming increasingly interested in the knowledge of the real performance of PV systems and the most frequent sources of problems that they suffer to be able to target the identified challenges properly. The scientific and industrial PV community is also requiring an access to massive operational data to pursue the technological improvements further.

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Hoy en día, existen numerosos sistemas (financieros, fabricación industrial, infraestructura de servicios básicos, etc.) que son dependientes del software. Según la definición de Ingeniería del Software realizada por I. Sommerville, “la Ingeniería del Software es una disciplina de la ingeniería que comprende todos los aspectos de la producción de software desde las etapas iniciales de la especificación del sistema, hasta el mantenimiento de éste después de que se utiliza.” “La ingeniería del software no sólo comprende los procesos técnicos del desarrollo de software, sino también actividades tales como la gestión de proyectos de software y el desarrollo de herramientas, métodos y teorías de apoyo a la producción de software.” Los modelos de proceso de desarrollo software determinan una serie de pautas para poder desarrollar con éxito un proyecto de desarrollo software. Desde que surgieran estos modelos de proceso, se investigado en nuevas maneras de poder gestionar un proyecto y producir software de calidad. En primer lugar surgieron las metodologías pesadas o tradicionales, pero con el avance del tiempo y la tecnología, surgieron unas nuevas llamadas metodologías ágiles. En el marco de las metodologías ágiles cabe destacar una determinada práctica, la integración continua. Esta práctica surgió de la mano de Martin Fowler, con el objetivo de facilitar el trabajo en grupo y automatizar las tareas de integración. La integración continua se basa en la construcción automática de proyectos con una frecuencia alta, promoviendo la detección de errores en un momento temprano para poder dar prioridad a corregir dichos errores. Sin embargo, una de las claves del éxito en el desarrollo de cualquier proyecto software consiste en utilizar un entorno de trabajo que facilite, sistematice y ayude a aplicar un proceso de desarrollo de una forma eficiente. Este Proyecto Fin de Grado (PFG) tiene por objetivo el análisis de distintas herramientas para configurar un entorno de trabajo que permita desarrollar proyectos aplicando metodologías ágiles e integración continua de una forma fácil y eficiente. Una vez analizadas dichas herramientas, se ha propuesto y configurado un entorno de trabajo para su puesta en marcha y uso. Una característica a destacar de este PFG es que las herramientas analizadas comparten una cualidad común y de alto valor, son herramientas open-source. El entorno de trabajo propuesto en este PFG presenta una arquitectura cliente-servidor, dado que la mayoría de proyectos software se desarrollan en equipo, de tal forma que el servidor proporciona a los distintos clientes/desarrolladores acceso al conjunto de herramientas que constituyen el entorno de trabajo. La parte servidora del entorno propuesto proporciona soporte a la integración continua mediante herramientas de control de versiones, de gestión de historias de usuario, de análisis de métricas de software, y de automatización de la construcción de software. La configuración del cliente únicamente requiere de un entorno de desarrollo integrado (IDE) que soporte el lenguaje de programación Java y conexión con el servidor. ABSTRACT Nowadays, numerous systems (financial, industrial production, basic services infrastructure, etc.) depend on software. According to the Software Engineering definition made by I.Sommerville, “Software engineering is an engineering discipline that is concerned with all aspects of software production from the early stages of system specification through to maintaining the system after it has gone into use.” “Software engineering is not just concerned with the technical processes of software development. It also includes activities such as software project management and the development of tools, methods, and theories to support software production.” Software development process models determine a set of guidelines to successfully develop a software development project. Since these process models emerged, new ways of managing a project and producing software with quality have been investigated. First, the so-called heavy or traditional methodologies appeared, but with the time and the technological improvements, new methodologies emerged: the so-called agile methodologies. Agile methodologies promote, among other practices, continuous integration. This practice was coined by Martin Fowler and aims to make teamwork easier as well as automate integration tasks. Nevertheless, one of the keys to success in software projects is to use a framework that facilitates, systematize, and help to deploy a development process in an efficient way. This Final Degree Project (FDP) aims to analyze different tools to configure a framework that enables to develop projects by applying agile methodologies and continuous integration in an easy and efficient way. Once tools are analyzed, a framework has been proposed and configured. One of the main features of this FDP is that the tools under analysis share a common and high-valued characteristic: they are open-source. The proposed framework presents a client-server architecture, as most of the projects are developed by a team. In this way, the server provides access the clients/developers to the tools that comprise the framework. The server provides continuous integration through a set of tools for control management, user stories management, software quality management, and software construction automatization. The client configuration only requires a Java integrated development environment and network connection to the server.

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The Competency-Based Education in the context of training is intended as a comprehensive approach that seeks to link education with the productive sector and increase the potential of individuals, in the face of social, economic, political and cultural transformations that suffers the world and the contemporary society; this is how educational services associated to the rural area takes part of the global revalorization of the role of learning and knowledge. Under the competence approach and taking into account the CONOCER model, we design a Technological Master from the “Colegio de Postgraduados” identifying the competences needed so that the students, professional from different areas of knowledge, managed to develop them, but mainly to achieve the goal of developing the capacities of producers in Mexican rural area.

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We investigated the atomic surface properties of differently prepared silicon and germanium (100) surfaces during metal-organic vapour phase epitaxy/chemical vapour deposition (MOVPE/MOCVD), in particular the impact of the MOVPE ambient, and applied reflectance anisotropy/difference spectroscopy (RAS/RDS) in our MOVPE reactor to in-situ watch and control the preparation on the atomic length scale for subsequent III-V-nucleation. The technological interest in the predominant opto-electronic properties of III-V-compounds drives the research for their heteroepitaxial integration on more abundant and cheaper standard substrates such as Si(100) or Ge(100). In these cases, a general task must be accomplished successfully, i.e. the growth of polar materials on non-polar substrates and, beyond that, very specific variations such as the individual interface formation and the atomic step structure, have to be controlled. Above all, the method of choice to grow industrial relevant high-performance device structures is MOVPE, not normally compatible with surface and interface sensitive characterization tools, which are commonly based on ultrahigh vacuum (UHV) ambients. A dedicated sample transfer system from MOVPE environment to UHV enabled us to benchmark the optical in-situ spectra with results from various surfaces science instruments without considering disruptive contaminants. X-ray photoelectron spectroscopy (XPS) provided direct observation of different terminations such as arsenic and phosphorous and verified oxide removal under various specific process parameters. Absorption lines in Fourier-transform infrared (FTIR) spectra were used to identify specific stretch modes of coupled hydrides and the polarization dependence of the anti-symmetric stretch modes distinguished different dimer orientations. Scanning tunnelling microscopy (STM) studied the atomic arrangement of dimers and steps and tip-induced H-desorption proved the saturation of dangling bonds after preparati- n. In-situ RAS was employed to display details transiently such as the presence of H on the surface at lower temperatures (T <; 800°C) and the absence of Si-H bonds at elevated annealing temperature and also surface terminations. Ge buffer growth by the use of GeH4 enables the preparation of smooth surfaces and leads to a more pronounced amplitude of the features in the spectra which indicates improvements of the surface quality.

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This paper shows the development of a science-technological knowledge transfer model in Mexico, as a means to boost the limited relations between the scientific and industrial environments. The proposal is based on the analysis of eight organizations (research centers and firms) with varying degrees of skill in the practice of science-technological knowledge transfer, and carried out by the case study approach. The analysis highlights the synergistic use of the organizational and technological capabilities of each organization, as a means to identification of the knowledge transfer mechanisms best suited to enabling the establishment of cooperative processes, and achieve the R&D and innovation activities results.

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decade has raised the interest among the research community on the acceptance and use of these systems by both teachers and students. At first, the implementation of LMS was based on their technical design and the adaptation of the learning processes to the virtual environment, neglecting students’ characteristics when the systems were deployed, which led to expensive and failing implementations. The Unified Theory of Acceptance and Use of Technology (UTAUT) proposes a framework which allows the study of the acceptance and use of technology that takes into consideration the students’ characteristics and how they affect the acceptance and the degree of use of educational technology. This study questions the role of the user’s attitude towards use of LMS and uses the UTAUT to examine the moderating effect of technological culture in the adoption of LMS in Spain. The results from the comparison and analysis of three different models confirm the relevance of attitude towards use as an antecedent of intention to use the system, as well as the important moderating effect of gender and technological culture. The discussion of results suggests the need for a more in-depth analysis and interrelations of cultural dimensions in the adoption of educational technologies and learning management systems

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This work presents a solution for the aerial coverage of a field by using a fleet of aerial vehicles. The use of Unmanned Aerial Vehicles allows to obtain high resolution mosaics to be used in Precision Agriculture techniques. This report is focus on providing a solution for the full simultaneous coverage problem taking into account restrictions as the required spatial resolution and overlap while maintaining similar light conditions and safety operation of the drones. Results obtained from real field tests are finally reported

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Tabled evaluation has been proved an effective method to improve several aspeets of goal-oriented query evaluation, including termination and complexity. Several "native" implementations of tabled evaluation have been developed which offer good performance, but many of them need significant changes to the underlying Prolog implementation. More portable approaches, generally using program transformation, have been proposed but they often result in lower efficieney. We explore some techniques aimed at combining the best of these worlds, i.e., developing a portable and extensible implementation, with minimal modifications at the abstract machine level, and with reasonably good performance. Our preliminary results indícate promising results.

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La mejora en la eficiencia energética y la reducción de la tasa de fallos en los contactos lubricados son aspectos que resultan de gran interés en numerosos sectores de la industria, y plantean en estos momentos nuevas dificultades operativas y retos para un futuro próximo. Los avances tecnológicos han incrementado las exigencias técnicas que se requieren a los aceites para cumplir su función al extender sus variables operativas a un mayor espectro de aplicaciones, tanto de condiciones de funcionamiento como a la gran variedad de nuevos materiales constitutivos de los engranajes en los que se tiene que utilizar. Por ello, actualmente se está incentivado el desarrollo de nuevos procedimientos que permitan comprender el comportamiento de este tipo de contactos lubricados, con el fin de lograr mejoras técnicas en su diseño y la correcta selección del aceite. En esta Tesis Doctoral se presenta una metodología de cálculo numérico que permite simular el comportamiento de contactos elastohidrodinámicos (EHD) puntuales, como puede ser el caso de un rodamiento. La resolución de este problema presenta diversas complejidades matemáticas y exige el desarrollo de un elaborado procedimiento de cálculo basado en técnicas multinivel. Para hacer del procedimiento una herramienta válida en un gran número de condiciones de funcionamiento y tipos de lubricantes, se ha tenido en cuenta en el cálculo la posible aparición de comportamientos no-Newtonianos del lubricante y fenómenos de generación y disipación de calor, provocados por el movimiento relativo del fluido y las superficies en contacto. Para la validación del procedimiento, se han contrastado los resultados numéricos obtenidos con nuestro método, con los resultados numéricos y experimentales publicados por otros autores y con valores experimentales propios medidos en un equipo de ensayo de contacto puntual tipo MTM. El desarrollo de este programa ha dotado a la División de Ingeniería de Máquinas de una herramienta que ha permitido, y sobre todo va permitir, evaluar la importancia de cada uno de los parámetros reológicos en los diferentes problemas que va a tener que abordar, evaluación que hasta el momento se realizaba con métodos aproximados que describen la fenomenología con mucha menos precisión. A la hora de emplear nuestro procedimiento numérico para simular situaciones reales, nos hemos encontrado con el obstáculo de que es muy complicado encontrar, en la bibliografía y bases de datos, los parámetros que caracterizan el comportamiento reológico del lubricante en las condiciones de presión, temperatura y grado de cizallamiento habituales en las que se trabaja en este tipo de contactos, y las pocas medidas que existen para estas condiciones de funcionamiento son poco fiables. Por ello como complemento al objetivo principal de esta Tesis hemos desarrollado una metodología para caracterizar los lubricantes en estas condiciones extremas. Dicha metodología está basada en la buena descripción que hace nuestro programa del coeficiente de fricción, lo que nos ha permitido obtener los parámetros reológicos del III lubricante a partir de las medidas experimentales del coeficiente de fricción generado en un equipo MTM lubricado con el lubricante que se desea caracterizar. Madrid, Octubre de 2012 IV Improving energy efficiency and reducing the failure rate in lubricated contacts are issues that are of great interest in many sectors of industry, and right now posed operational difficulties and new challenges for the near future. Technological advances have increased the technical demands required to oils to fulfil its role by extending its operational variables to a wider range of applications, both operating conditions and to the wide variety of new materials which constitute the gear in which must be used. For this reason, has being encouraged currently to develop new procedures to understand the behaviour of this type of lubricated contacts, in order to achieve improvements in design techniques and the correct oil selection. In this Thesis we present a numerical methodology to simulate the puntual elastohydrodynamic contact behaviour (EHD), such as a roller bearing. The resolution of this problem presents various mathematical complexities and requires the development of an elaborate calculation procedure based on multilevel techniques. To make the procedure a valid tool in a wide range of operating conditions and types of lubricants, has been taken into account in calculating the possible occurrence of non-Newtonian behaviour of the lubricant and phenomena of generation and dissipation of heat, caused by the fluid relative motion and contacting surfaces. For the validation of the method, we have compared the numerical results obtained with our method with numerical and experimental results published by other authors also with own experimental values measured on point-contact test equipment MTM. The development of this program has provided the Machines Engineering Division of a tool that has allowed, and especially will allow to evaluate the importance of each of the rheological parameters on the various problems that will have to be addressed, evaluation performed hitherto described methods that phenomenology approximated with much less accuracy. When using our numerical procedure to simulate real situations we have encountered the obstacle that is very difficult to find, in the literature and database, parameters characterizing the rheological behaviour of the lubricant in the usual conditions of pressure, temperature and shear rate in which you work in this type of contact, and the few measures that exist for these operating conditions are unreliable. Thus in addition to the main objective of this thesis, we have developed a methodology to characterize the lubricants in these extreme conditions. This methodology is based on the good description, which makes our program, of the coefficient of friction, that allowed us to obtain the lubricant rheological parameters from experimental measurements of the friction coefficient generated on lubricated MTM equipment with the lubricant to be characterized.