3,743 research outputs found

    A study of emerging opportunities for digital print production of user-generated content

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    Changes in information consumption habits have been especially rapid and deep in the last five years. As examples, Facebook, with more than 90 millions users at the time of this writing, was launched on 2004, and YouTube, a new model that has revolutionized the way the users are getting content, as well as the content itself, started in 2005. These rapid changes are threatening the printing industry. What will be the motivation and environment for consumers to print? What content will consumers prefer to print? What values will consumers appreciate in the print product versus the digital? What will be the role of the printing industry in this new environment? This research is focused exclusively on personal printed products that are created by the current US college-aged population, and offers a prediction for the research questions based mainly on the analysis of 21 interviews conducted with experts in the printing industry and on a wide literature review. The main conclusions obtained in this study are: The current college-aged US population has a very limited interest for printed personal products at their current stage of life, but this interest will grow substantially in the next years. They will print many more personal products than the previous generation did, very often through a social networking environment. The content of these new products will be more visual and more personal, covering all kinds of daily events. Users will use mostly their own content, but they will be able to blend it with professionally created content in a broad gamut of products. Personal printed products will extend to other products and substrates, such as textiles. Printed products are perceived less as a useful or convenient and more as a sensorial and fixed products, something that has value itself. The value of the printed products is precisely that they cannot be used for a purpose other than the purpose of the author. They cannot be reprinted. The industry has to make the process extremely easy for the user, to remove knowledge needed, to be accessible from everywhere at any time, and to make the whole process easy, fast, and fun. The new professionals will need to understand the whole workflow as a manufacturing process, to improve communication skills, to pay more attention to customer service, and to understand how databases interact with content to customize any printed product

    Concrete Swelling in Existing Dams

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    Several chemical reactions are able to produce swelling of concrete for decades after its initial curing, a problem that affects a considerable number of concrete dams around the world. Principia has had several contracts to study this problem in recent years, which have required reviewing the state-of-the-art, adopting appropriate mathematical descriptions, programming them into user routines in Abaqus, determining model parameters on the basis of some parts of the dams’ monitored histories, ensuring reliability using some other parts, and finally predicting the future evolution of the dams and their safety margins. The paper describes some of the above experience, including the programming of sophisticated non-isotropic swelling models, that must be compatible with cracking and other nonlinearities involved in concrete behaviour. The applications concentrate on two specific cases, an archgravity dam and a double-curvature arch dam, both with a long history of concrete swelling and which, interestingly, entailed different degrees of success in the modelling effort

    Post-cracking Behabiour of a Wind Turbine Concrete Tower

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    The paper deals with the dynamic performance of a simply reinforced concrete tower built using prefabricated elements. The main uncertainty of this strategy stems from the possible cracking of the concrete and its implications on the stiffness, natural frequency and dynamic amplification of the tower. In 2006 an 80 m high prototype was built, supporting a 1.5 MW wind generator, carefully instrumented and test loaded to 80% of its design capacity. The prototype and installed instrumentation remained in operation for 3 years. Detailed calculations were carried out of the cracking induced in the concrete and its effects on the natural frequency of the tower, as a function of wind speed and orientation; the results were compared with the monitoring data. It is concluded that numerical modelling with Abaqus allowed good predictions and interpretations of the observed response of the tower. Also, simply reinforced concrete is shown to be a good option for high towers; if the structure is well designed, the natural frequency will not migrate to a point where its proximity to the forcing frequency will lead to unacceptable levels of the dynamic amplification

    Integral Bridge for High-Speed Railway

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    The structural continuity of fully integral bridges entails many advantages and some drawbacks. Among the latter, the cyclic expansions and contractions of the deck caused by seasonal thermal variations impose alternating displacements at the piers and abutments, with effects that may be difficult to establish reliably. The advantages include easier construction and cheaper maintenance but, especially, horizontal loads can be transmitted to the ground in a much better way than in conventional bridges. This paper first presents a methodology for dealing with the problems that the cyclic displacements imposed raise at the abutments and at the bridge piers. At the former, large pressures may develop, possibly accompanied by undesirable surface settlements. At the latter, the degree of cracking and the ability to carry the specified loads may be in question. Having quantified the drawbacks, simplified but realistic analyses are conducted of the response of an integral bridge to braking and seismic loads. It is shown that integral bridges constitute an excellent alternative in the context of the requirements posed by new high-speed railway lines

    Concrete constitutive model, calibration and applications

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    A methodology has been developed for characterising the mechanical behaviour of concrete, based on the damaged plasticity model, enriched with a user subroutine (V)USDFLD in order to capture better the ductility of the material under moderate confining pressures. The model has been applied in the context of the international benchmark IRIS_2012, organised by the OECD/NEA/CSNI Nuclear Energy Agency, dealing with impacts of rigid and deformable missiles against reinforced concrete targets. A slightly modified version of the concrete damaged plasticity model was used to represent the concrete. The simulation results matched very well the observations made during the actual tests. Particularly successful predictions involved the energy spent by the rigid missile in perforating the target, the crushed length of the deformable missile, the crushed and cracked areas of the concrete target, and the values of the strains recorded at a number of locations in the concrete slab

    Concrete Swelling in Two Spanish Dams

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    Several chemical reactions are able to produce swelling of concrete for decades after its initial curing, a problem that affects a considerable number of concrete dams around the world. Principia has had several contracts to study this problem in recent years, which have required reviewing the state-ofthe-art, adopting appropriate mathematical descriptions, programming them into user routines in Abaqus, determining model parameters on the basis of some parts of the dams’ monitored histories, ensuring reliability using some other parts, and finally predicting the future evolution of the dams and their safety margins. The paper describes some of the above experience, including the programming of sophisticated nonisotropic swelling models, that must be compatible with cracking and other nonlinearities involved in concrete behaviour. The applications concentrate on two specific cases, an arch-gravity dam and a double-curvature arch dam, both with a long history of concrete swelling and which, interestingly, entailed different degrees of success in the modelling effort

    Ambulance detection for smart traffic light applications with fuzzy controller

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    In the development of intelligent cities, the automation of vehicular mobility is one of the strong points of research, where intelligent traffic lights stand out. It is essential in this field to prioritize emergency vehicles that can help save lives, where every second counts in favor of the transfer of a patient or injured person. This paper presents an artificial intelligence algorithm based on two stages, one is the recognition of emergency vehicles through a ResNet-50 and the other is a fuzzy inference system for timing control of a traffic light, both lead to an intelligent traffic light. An application of traffic light vehicular flow control for automatic preemption when detecting emergency vehicles, specifically ambulances, is oriented. The training parameters of the network, which achieves 100% accuracy with confidence levels between 65% with vehicle occlusion and 99% in direct view, are presented. The traffic light cycles are able to extend the green time of the traffic light with almost 50% in favor of the road that must yield the priority, in relation to not using the fuzzy inference system
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