On the Evaluation of the Mechanical Behaviour of Structural Glass Elements

Glass can be considered to be a high-technology engineering material with a multifunctional potential for structural applications. However, the conventional approach to the use of glass is often based only on its properties of transparency and isolation. It is thus highly appropriate and necessary to study the mechanical behaviour of this material and to develop adequate methods and models leading to its characterisation. It is evident that the great potential of growth for structural glass applications is an important opportunity of development for the glass industry and the building/construction sectors. The work presented in this paper is a reflection of this conclusion. The authors shortly present the state-of-the-art on the application of glass as a structural element in building and construction, and refer to other potential fields of application and available glass materials. The experimental procedures and methods adopted in three-point bending tests performed on 500 × 100 [mm2] float, laminated and tempered glass specimens with thicknesses between 4 and 19 mm are thoroughly described. The authors evaluated the mechanical strength and stiffness of glass for structural applications. This work contributes to a deeper knowledge of the properties of this material

Ontology Driven Knowledge Extraction System with Application in e-Government

Important sources of information are originally created in natural language. To make that knowledge computer processable it is necessary to understand the structure of natural languages, by adding lexical and syntactic information; to have a rich representation to encode the knowledge of sentences, like ontologies; and to develop algorithms to bridge the gap between natural languages and computer processable representations. In this paper we present the architecture, modules and results of a prototype that uses an ontology to represent the world concepts and their relationships, and also to guide the process of extracting information from natural language documents. The system was tested using minutes of Portuguese municipalities’ meetings. Initial results are presented for three topics of municipalities' affairs: the subsidies granted, the building permits requested, and the existing protocols with other institutions

Simultaneously assess goat fat depots using ultrasound technology (RTU) in association with muliple PLS and ANN models. A network proposal

A recent development to improve the prediction of goat body or carcass composition in small has been made. With the perspective to use a unique model to estimate body composition, based on a reduced number of predictors a model using artificial neural networks was proposed. On this sense the main objective of the present work will be to demonstrate the necessity to organize a world network to build a great database, covering the most relevant carcass and body compositions data, for the most important goat breeds at different maturity degrees and with carcasses that proportionate the development of general, robust, and more reliable models to swiftly assess goat and carcass body compositions, as well as to implement a modern and objective on-line technique for carcass evaluation and marketing classification

Towards a silent speech interface for Portuguese: Surface electromyography and the nasality challenge

A Silent Speech Interface (SSI) aims at performing Automatic Speech Recognition (ASR) in the absence of an intelligible acoustic signal. It can be used as a human-computer interaction modality in high-background-noise environments, such as living rooms, or in aiding speech-impaired individuals, increasing in prevalence with ageing. If this interaction modality is made available for users own native language, with adequate performance, and since it does not rely on acoustic information, it will be less susceptible to problems related to environmental noise, privacy, information disclosure and exclusion of speech impaired persons. To contribute to the existence of this promising modality for Portuguese, for which no SSI implementation is known, we are exploring and evaluating the potential of state-of-the-art approaches. One of the major challenges we face in SSI for European Portuguese is recognition of nasality, a core characteristic of this language Phonetics and Phonology. In this paper a silent speech recognition experiment based on Surface Electromyography is presented. Results confirmed recognition problems between minimal pairs of words that only differ on nasality of one of the phones, causing 50% of the total error and evidencing accuracy performance degradation, which correlates well with the exiting knowledge.info:eu-repo/semantics/acceptedVersio

Assessment of goat fat depots using ultrasound technology and multiple multivariate prediction models

Assessment of fat depots for several goat body parts is an expensive and time-consuming task requiring a trained technician. Therefore, the establishment of models to predict fat depots based on data requiring simpler and easier procedures, such as ultrasound measurements, that could be carried out in vivo, would be a major advantage. An interesting alternative to the use of multiple linear regression models is the use of partial least squares or artificial neural network models because they allow the establishment of one model to simultaneously predict different fat depots of interest. In this work, the applicability of these models to simultaneously predict 7 goat fat depots (subcutaneous fat, intermuscular fat, total carcass fat, omental fat, kidney and pelvic fat, mesenteric fat, and total body fat) was investigated. Although satisfactory correlation and prediction results were obtained using the multiple partial least squares model (cross-verification and validation R2 and standard prediction error values between 0.66 and 0.98 and 247 and 2,168, respectively), the best global correlation and prediction performances were achieved with the multiple radial basis function artificial neural network (verification and validation R2 and standard prediction error values between 0.82 and 0.96 and 304 and 1,707, respectively). These 2 multiple models allowed correlating and predicting simultaneously the 7 goat fat depots based on the goat BW and on only 2 ultrasonic measures (lumbar subcutaneous fat between fifth and sixth vertebrae and the fat depth at the third sternebra). Moreover, both multiple models showed better results compared with those obtained with multiple linear regression models proposed in previous work

As Potencialidades do vidro como material estrutural

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Tuned liquid dampers simulation for earthquake response control of buildings

This paper is focused on the study of an earthquake protection system, the Tuned Liquid Damper (TLD), which can, if adequately designed, reduce earthquake demands on buildings. This positive effect is accomplished taking into account the oscillation of the free surface of a fluid inside a tank (sloshing). The behaviour of an isolated Tuned Liquid Damper, subjected to a sinusoidal excitation at its base, with different displacement amplitudes, was studied by finite element analysis. The efficiency of the TLD in improving the seismic response of an existing building, representative of modern architecture buildings in southern European countries was also evaluated based on linear dynamic analyses

Dynamic capabilities: Antecedents and implications for firms' performance

Purpose: This paper aims to explore a new causal link between learning, market and entrepreneurial orientations and firms' performance by introducing dynamic capabilities and competitive advantages as mediator variables. Design/methodology/approach: The mediating role of dynamic capabilities and competitive advantages is tested using a sample of 1,190 Portuguese firms, and structural equation models. Findings: It is shown that dynamic capabilities mediate the relationship between the three orientations–learning, market and entrepreneurial–and competitive advantages of differentiation and cost leadership, and both competitive advantages lead to firm's performance. It is also shown that learning orientation is an antecedent of market orientation and entrepreneurial orientation. Practical implications: This research shows that firm's performance depends on the capacity of firms to learn, innovate, be proactive, take risks and collect the best market data. Indeed, by optimizing the internal management and knowledge dissemination, firms will develop a set of capabilities and competitive advantages that lead to an appropriate response to market challenges. Originality/value: This study tests the relationship between strategic orientations and firm's performance by taking the mediating effects of dynamic capabilities and competitive advantages into account. This research was conducted in Portugal.info:eu-repo/semantics/acceptedVersio

Tortuosity variation in a low density binary particulate bed

The importance of particle size ratio and particle composition in the properties of a mixed bed is well known. Nevertheless, the dependence of the bed channel tortuosity T on the porosity ε in the form T=1/εn, where n is assumed to be a constant, shows that the value of n depends on the properties of the packed bed. For loose packing, experimental data for binary mixtures of glass beads of a size ratio from 1 up to 53.8 was analysed in terms of porosity, tortuosity and permeability. The packing procedure was performed without intensive compacting methods e.g. vibration, etc. Obtained results show that the parameter n is a function of the volume fraction of large particles xD and, for spherical particles, lies in the range 0.4–0.5. The explanation for this variation is (1) a distortion effect on the small particles arrangement occurring near the large particle surface; (2) in the region of minimum porosity, near contact points of large particles, the occurrence of dead zones that are free of small particles. A relationship accounting for this effect is proposed that may be useful for the analysis of transport phenomena in granular bed filters, chromatographic columns, etc.Fundação para a Ciência e a Tecnologia FCT); FEDE

Particulate binary mixtures : dependence of packing porosity on particle size ratio

Binary mixtures with significant size ratios are scarcely studied. Yet, contaminants of chromatographic columns or ion-exchange resins have size ratios of delta < 0.1. Binary mixtures of glass beads with delta = 0.1-0.0375 were used experimentally to measure packing porosity. Simultaneously, a significant number of published data was analyzed. A linear mixing model was adopted to predict the porosity of each particle fraction in the binary mixture. Deviations from the model may be caused by wedging of small particles between the large ones. Large particles may disturb the porous medium properties by inducing a wall effect over the small particles. Wedging analysis led to the conclusion that, for delta < 0.01, its effect is insignificant. The wall effect yields an additional void around the large particles as long as delta > 0.0035. For delta < 0.0035, the small particles form a monosized dense packing and both wedging and wall effects become negligible.Fundação para a Ciência e a Tecnologia (FCT) e FEDER – POCTI/EQU/37500/2001