818 resultados para technological frames


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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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In the present work a seismic retrofitting technique is proposed for masonry infilled reinforced concrete frames based on the replacement of infill panels by K-bracing with vertical shear link. The performance of this technique is evaluated through experimental tests. A simplified numerical model for structural damage evaluation is also formulated according to the notions and principles of continuum damage mechanics. The proposed model is calibrated with the experimental results. The experimental results have shown an excellent energy dissipation capacity with the proposed technique. Likewise, the numerical predictions with the proposed model are in good agreement with experimental results.

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To model strength degradation due to low cycle fatigue, at least three different approaches can be considered. One possibility is based on the formulation of a new free energy function and damage energy release rate, as was proposed by Ju(1989). The second approach uses the notion of bounding surface introduced in cyclic plasticity by Dafalias and Popov (1975). From this concept, some models have been proposed to quantify damage in concrete or RC (Suaris et al. 1990). The model proposed by the author to include fatigue effects is based essentially in Marigo (1985) and can be included in this approach.

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Damage models based on the Continuum Damage Mechanics (CDM) include explicitly the coupling between damage and mechanical behavior and, therefore, are consistent with the definition of damage as a phenomenon with mechanical consequences. However, this kind of models is characterized by their complexity. Using the concept of lumped models, possible simplifications of the coupled models have been proposed in the literature to adapt them to the study of beams and frames. On the other hand, in most of these coupled models damage is associated only with the damage energy release rate which is shown to be the elastic strain energy. According to this, damage is a function of the maximum amplitude of cyclic deformation but does not depend on the number of cycles. Therefore, low cycle effects are not taking into account. From the simplified model proposed by Flórez-López, it is the purpose of this paper to present a formulation that allows to take into account the degradation produced not only by the peak values but also by the cumulative effects such as the low cycle fatigue. For it, the classical damage dissipative potential based on the concept of damage energy release rate is modified using a fatigue function in order to include cumulative effects. The fatigue function is determined through parameters such as the cumulative rotation and the total rotation and the number of cycles to failure. Those parameters can be measured or identified physically through the haracteristics of the RC. So the main advantage of the proposed model is the possibility of simulating the low cycle fatigue behavior without introducing parameters with no suitable physical meaning. The good performance of the proposed model is shown through a comparison between numerical and test results under cycling loading.

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A large number of reinforced concrete (RC) frame structures built in earthquake-prone areas such as Haiti are vulnerable to strong ground motions. Structures in developing countries need low-cost seismic retrofit solutions to reduce their vulnerability. This paper investigates the feasibility of using masonry infill walls to reduce deformations and damage caused by strong ground motions in brittle and weak RC frames designed only for gravity loads. A numerical experiment was conducted in which several idealized prototypes representing RC frame structures of school buildings damaged during the Port-au-Prince earthquake (Haiti, 2010) were strengthened by adding elements representing masonry infill walls arranged in different configurations. Each configuration was characterized by the ratio Rm of the area of walls in the direction of the ground motion (in plan) installed in each story to the total floor area. The numerical representations of these idealized RC frame structures with different values of Rm were (hypothetically) subjected to three major earthquakes with peak ground accelerations of approximately 0.5g. The results of the non-linear dynamic response analyses were summarized in tentative relationships between Rm and four parameters commonly used to characterize the seismic response of structures: interstory drift, Park and Ang indexes of damage, and total amount of energy dissipated by the main frame. It was found that Rm=4% is a reasonable minimum design value for seismic retrofitting purposes in cases in which available resources are not sufficient to afford conventional retrofit measures.

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From the end of 2013 and during the following two years, 20 kt of CO2sc are planned to be injected in a saline reservoir (1500 m depth) at the Hontomín site (NE Spain). The target aquifers are Lower Jurassic limestone formations which are sealed by Lower Cretaceous clay units at the Hontomín site (NE Spain). The injection of CO2 is part of the activities committed in the Technology Development phase of the EC-funded OXYCFB300 project (European Energy Program for Recovery – EEPR, http://www.compostillaproject.eu), which include CO2 injection strategies, risk assessment, and testing and validating monitoring methodologies and techniques. Among the monitoring works, the project is intended to prove that present-day technology is able to monitor the evolution of injected CO2 in the reservoir and to detect potential leakage. One of the techniques is the measurement of CO2 flux at the soil–atmosphere interface, which includes campaigns before, during and after the injection operations. In this work soil CO2 flux measurements in the vicinity of oil borehole, drilled in the eighties and named H-1 to H-4, and injection and monitoring wells were performed using an accumulation chamber equipped with an IR sensor. Seven surveys were carried out from November 2009 to summer 2011. More than 4000 measurements were used to determine the baseline flux of CO2 and its seasonal variations. The measured values were low (from 5 to 13 g m−2 day−1) and few outliers were identified, mainly located close to the H-2 oil well. Nevertheless, these values cannot be associated to a deep source of CO2, being more likely related to biological processes, i.e. soil respiration. No anomalies were recognized close to the deep fault system (Ubierna Fault) detected by geophysical investigations. There, the CO2 flux is indeed as low as other measurement stations. CO2 fluxes appear to be controlled by the biological activity since the lowest values were recorded during autumn-winter seasons and they tend to increase in warm periods. Two reference CO2 flux values (UCL50 of 5 g m−2 d−1 for non-ploughed areas in autumn–winter seasons and 3.5 and 12 g m−2 d−1 for in ploughed and non-ploughed areas, respectively, in spring–summer time, and UCL99 of 26 g m−2 d−1 for autumn–winter in not-ploughed areas and 34 and 42 g m−2 d−1 for spring–summer in ploughed and not-ploughed areas, respectively) were calculated. Fluxes higher than these reference values could be indicative of possible leakage during the operational and post-closure stages of the storage project.

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The effect of infill walls on the behaviour of frames is widely recognized, and, for several decades now, has been the subject of numerous experimental investigations. However, the analytical modeling of infilled panels and frames under in-plane loading is difficult and generally unreliable. From the point of view of the simulation technique the models may be divided into micromodels and simplified (or macro-) models. Based on the equivalent strut approach (simplified model), in this paper a damage model is proposed for the characterization of masonry walls submitted to lateral cyclic loads. The model, developed along the lines of the Continuum Damage Mechanics, have the advantages of including explicitly the coupling between damage and mechanical behaviour and so is consistent with the definition of damage as a phenomenon with mechanical consequences.

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Many studies have been developed to analyze the structural seismic behavior through the damage index concept. The evaluation of this index has been employed to quantify the safety of new and existing structures and, also, to establish a framework for seismic retrofitting decision making of structures. Most proposed models are based in a posterthquake evaluation in such a way they uncouple the structural response from the damage evaluation. In this paper, a generalization of the model by Flórez-López (1995) is proposed. The formulation employs irreversible thermodynamics and internal state variable theory applied to the study of beams and frames and it allows and explicit coupling between the degradation and the structural mechanical behavior. A damage index es defined in order to model elastoplasticity coupled with damage and fatigue damage.

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Nowadays "Flood Resilient (FRe) Building Technological Products" is an undefined concept, and concerned FRe solutions cannot be even easily identified. There is an interest in offering an identification and classification of the referred products, since it will be useful for stakeholders and populations at flood risk for adopting the most adequate protections when facing floods. There are many barriers for the implementation of "FRe building technological products", and particularly their standardization is still a major challenge. To put into contact such solutions with final customers, it appears necessary to protocolize them all. The classification effort achieved in this document shall be considered as a necessary preliminary step in order to open the road to the market to FRe building technological solutions.

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En este proyecto se desarrolla un sistema electrónico para variar la geometría de un motor de un monoplaza que participa en la competición Fórmula SAE. Fórmula SAE es una competición de diseño de monoplazas para estudiantes, organizado por “Society of Automotive Enginners” (SAE). Este concurso busca la innovación tecnológica de la automoción, así como que estudiantes participen en un trabajo real, en el cual el objetivo es obtener resultados competitivos cumpliendo con una serie de requisitos. La variación de la geometría de un motor en un vehículo permite mejorar el rendimiento del monoplaza consiguiendo elevar el par de potencia del motor. Cualquier mejora en del vehículo en un ámbito de competición puede resultar determinante en el desenlace de la misma. El objetivo del proyecto es realizar esta variación mediante el control de la longitud de los tubos de admisión de aire o “runners” del motor de combustión, empleando un motor lineal paso a paso. A partir de la información obtenida por sensores de revoluciones del motor de combustión y la posición del acelerador se debe controlar la distancia de dichos tubos. Integrando este sistema en el bus CAN del vehículo para que comparta la información medida al resto de módulos. Por todo esto se realiza un estudio aclarando los aspectos generales del objetivo del trabajo, para la comprensión del proyecto a realizar, las posibilidades de realización y adquisición de conocimientos para un mejor desarrollo. Se presenta una solución basada en el control del motor lineal paso a paso mediante el microcontrolador PIC32MX795F512-L. Dispositivo del fabricante Microchip con una arquitectura de 32 bits. Este dispone de un módulo CAN integrado y distintos periféricos que se emplean en la medición de los sensores y actuación sobre el motor paso a paso empleando el driver de Texas Instruments DRV8805. Entonces el trabajo se realiza en dos líneas, una parte software de programación del control del sistema, empleando el software de Microchip MPLABX IDE y otra parte hardware de diseño de una PCB y circuitos acondicionadores para la conexión del microcontrolador, con los sensores, driver, motor paso a paso y bus CAN. El software empleado para la realización de la PCB es Orcad9.2/Layout. Para la evaluación de las medidas obtenidas por los sensores y la comprobación del bus CAN se emplea el kit de desarrollo de Microchip, MCP2515 CAN Bus Monitor Demo Board, que permite ver la información en el bus CAN e introducir tramas al mismo. ABSTRACT. This project develops an electronic system to vary the geometry of a car engine which runs the Formula SAE competition. Formula SAE is a design car competition for students, organized by "Society of Automotive Engineers" (SAE). This competition seeks technological innovation in the automotive industry and brings in students to participate in a real job, in which the objective is to obtain competitive results in compliance with certain requirements. Varying engine’s geometry in a vehicle improves car’s performance raising engine output torque. Any improvement in the vehicle in a competition field can be decisive in the outcome of it. The goal of the project is the variation by controlling the length of the air intake pipe or "runners" in a combustion engine, using a linear motor step. For these, uses the information gathered by speed sensors from the combustion engine and by the throttle position to control the distance of these tubes. This system is integrated in the vehicle CAN bus to share the information with the other modules. For all this is made a study to clarify the general aspects of the project in order to understand the activities developed inside the project, the different options available and also, to acquire knowledge for a better development of the project. The solution is based on linear stepper motor control by the microcontroller PIC32MX795F512-L. Device from manufacturer Microchip with a 32-bit architecture. This module has an integrated CAN various peripherals that are used in measuring the performance of the sensors and drives the stepper motor using Texas Instruments DRV8805 driver. Then the work is done in two lines, first, control programming software system using software MPLABX Microchip IDE and, second, hardware design of a PCB and conditioning circuits for connecting the microcontroller, with sensors, driver stepper motor and CAN bus. The software used to carry out the PCB is Orcad9.2/Layout. For the evaluation of the measurements obtained by the sensors and CAN bus checking is used Microchip development kit, MCP2515 CAN Bus Monitor Demo Board, that allows you to see the information on the CAN bus and enter new frames in the bus.

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This paper is based on the following postulates taken from a book recently published by this author (Sáez-Vacas, 1990(1)): a) technological innovation in a company is understood to be the process and set of changes that the company undergoes as a result of a specific type of technology; b) the incorporation of technology in the company does not necessarily result in innovation, modernization and progress; c) the very words "modernization" and "progress" are completely bereft of any meaning if isolated from the concept of complexity in its broadest sense, including the human factor. Turning to office technology in specific, the problem of managing office technology for business innovation purposes can be likened to the problem of managing third level complexity, following the guidelines of a three-level complexity model proposed by the author some years ago

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Novel isotactic polypropylene (iPP)/glass fiber (GF) laminates reinforced with inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles as environmentally friendly fillers have been successfully fabricated by simple melt-blending and fiber impregnation in a hot-press without the addition of any compatibilizer. The influence of IF-WS2 concentration on the morphology, viscosity. and thermal and mechanical behavior of the hierarchical composites has been investigated. Results revealed an unprecedented 62 °C increase in the degradation temperature of iPP/GF upon addition of only 4.0 wt % IF-WS2. The coexistence of both micro- and nanoscale fillers resulted in synergistic effects on enhancing the stiffness, strength, crystallinity, thermal stability, glass transition (Tg) and heat distortion temperature (HDT) of the matrix. The approach used in this work is an efficient, versatile, scalable and economic strategy to improve the mechanical and thermal behavior of GF-reinforced thermoplastics with a view to extend their use in advanced technological applications. This new type of composite materials shows great potential to improve the efficiency and sustainability of many forms of transport.

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This paper concerns the characterization as frames of some sequences in U-invariant spaces of a separable Hilbert space H where U denotes an unitary operator defined on H ; besides, the dual frames having the same form are also found. This general setting includes, in particular, shift-invariant or modulation-invariant subspaces in L2 (R), where these frames are intimately related to the generalized sampling problem. We also deal with some related perturbation problems. In so doing, we need that the unitary operator U belongs to a continuous group of unitary operators.

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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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In recent years, international cooperation processes have become a key mechanism for companies to internationalise their innovative activities, par ticularly in the case of small businesses whose size reduces their possibilities of developing internationalisation strategies autonomously in the same way as larger companies. In Spain, the existence of two parallel programmes with similar structures oriented towards Europe (EUREKA) and Latin America (IBEROEKA) raises the question as to whether the fact that companies participate in only one (unipolar) or both (bipolar) of these programmes is the result of a selection process, which, in turn, results in the existence of different collectives with different efficiency parameters. The aim of this study is to provide a comparative analysis based on the final reports of Spanish companies that have participated in the EUREKA programme. Two groups of companies were compared: one comprising companies that have only had international experience in Europe (EUREKA); and another formed by companies that have also carried out IBEROEKA projects. The conclusions confirm that the behaviour of both groups of companies differs substantially and reveal the importance of geographical perspective in the analysis of international cooperation in technology. This disparate behaviour is a relevant aspect that must be taken into account when designing policies to promote international technological cooperation.