Taludes rochosos. Metodologias de inspec����o e de avaliali����o de seguran��a. Caso de estudo das vertentes rochosas de S. Sim��o

A instabiliza����o de taludes rochosos, com consequ��ncias mais ou menos gravosas, repete-se com frequ��ncia no territ��rio nacional. Os enquadramentos destes incidentes s��o diversos, sendo mais comum e mais vis��vel a sua ocorr��ncia em taludes adjacentes a vias de comunica����o. No entanto, o fen��meno repete-se tamb��m em vertentes naturais, geralmente em alturas de pluviosidade mais prolongada e intensa. No presente trabalho reveem-se conceitos associados a maci��os rochosos, nomeadamente as principais classifica����es geot��cnicas e as diferentes tipologias de instabilidade em taludes rochosos. Desenvolve-se um caso de estudo de uma vertente localizada em S. Sim��o, concelho de Amarante. Percorrem-se as sucessivas fases de estudo, incluindo a realiza����o da fotografia a��rea com recurso a um ve��culo n��o tripulado, a gera����o de um modelo 3D de elevada precis��o da vertente e a caracteriza����o e a classifica����o dos diferentes afloramentos rochosos. Desenvolve-se uma metodologia de inspe����o com a cria����o de dois conjuntos de fichas e prop��e-se o agravamento da classifica����o das anomalias perante a simultaneidade de ocorr��ncia de anomalias de id��ntica gravidade e a hierarquiza����o dos blocos potencialmente inst��veis, de acordo com os respetivos n��veis de gravidade (NGB). Recorre-se ao programa de modela����o da queda de blocos, ���Rocfall (4.0���, da ���Rocscience���, a partir de trajet��rias definidas no modelo 3D gerado e prop��em-se solu����es de refor��o e de prote����o da vertente.

A colonoscopia virtual no rastreio do cancro colo rectal

O cancro colo - rectal (CCR) �� um problema de sa��de mundial, estando associadas elevadas taxas de mortalidade e morbilidade. A maioria de CCR deriva de p��lipos adenomatosos.. Um estudo retrospectivo, efectuado no servi��o de Radiologia, dos achados imagiol��gicos t��picos e at��picos, entre Janeiro de 2008 e Junho 2010. A Colonoscopia Virtual, apresenta uma sensibilidade elevada na detec����o de les��es, com dimens��o superior a 10mm, permitindo um diagn��stico precoce, �� um exame r��pido, pouco invasivo, n��o h�� necessidade de seda����o e �� efectuada em ambulat��rio.

Extending access to remote labs from mobile devices in educational contexts

This paper describes how to extend the access to remote experiments from mobile devices, aiming to better engage digital native students who expect a more interactive and ubiquitous access mode. The extension is based on features of HTML5 and the jQuery Mobile framework, which allow accessing the experiments from different operating systems via the browser or native applications. As a result, users have a richer interaction mode with the experiments, which includes access from simple hand-held devices such as smartphones and PDAs. Extending the access to remote experiments, from simple devices, enables its use in other educational stages, such as high schools, where teachers struggle to engage students in STEM learning. By enabling students to use their everyday "technological companions", e.g. cellular phones, to access remote experiments, we seek to increase the educational value of this technology-enhanced learning resource.

A intera����o das marcas com o p��blico atrav��s do Facebook: o mercado dos smartphones e as marcas Samsung e Apple

Disserta����o de Mestrado apresentado ao Instituto de Contabilidade e Administra����o do Porto para a obten����o do grau de Mestre em Marketing Digital sob orienta����o de Sandrina Teixeira Anabela Ribeiro

Electrospun Polyaniline-Reduced Graphene Oxide Composite Nanofibers Based High Sensitive Ammonia Gas Sensor

Ammonia is an important gas in many power plants and industrial processes so its detection is of extreme importance in environmental monitoring and process control due to its high toxicity. Ammonia���s threshold limit is 25 ppm and the exposure time limit is 8 h, however exposure to 35 ppm is only secure for 10 min. In this work a brief introduction to ammonia aspects are presented, like its physical and chemical properties, the dangers in its manipulation, its ways of production and its sources. The application areas in which ammonia gas detection is important and needed are also referred: environmental gas analysis (e.g. intense farming), automotive-, chemical- and medical industries. In order to monitor ammonia gas in these different areas there are some requirements that must be attended. These requirements determine the choice of sensor and, therefore, several types of sensors with different characteristics were developed, like metal oxides, surface acoustic wave-, catalytic-, and optical sensors, indirect gas analyzers, and conducting polymers. All the sensors types are described, but more attention will be given to polyaniline (PANI), particularly to its characteristics, syntheses, chemical doping processes, deposition methods, transduction modes, and its adhesion to inorganic materials. Besides this, short descriptions of PANI nanostructures, the use of electrospinning in the formation of nanofibers/microfibers, and graphene and its characteristics are included. The created sensor is an instrument that tries to achieve a goal of the medical community in the control of the breath���s ammonia levels being an easy and non-invasive method for diagnostic of kidney malfunction and/or gastric ulcers. For that the device should be capable to detect different levels of ammonia gas concentrations. So, in the present work an ammonia gas sensor was developed using a conductive polymer composite which was immobilized on a carbon transducer surface. The experiments were targeted to ammonia measurements at ppb level. Ammonia gas measurements were carried out in the concentration range from 1 ppb to 500 ppb. A commercial substrate was used; screen-printed carbon electrodes. After adequate surface pre-treatment of the substrate, its electrodes were covered by a nanofibrous polymeric composite. The conducting polyaniline doped with sulfuric acid (H2SO4) was blended with reduced graphene oxide (RGO) obtained by wet chemical synthesis. This composite formed the basis for the formation of nanofibers by electrospinning. Nanofibers will increase the sensitivity of the sensing material. The electrospun PANI-RGO fibers were placed on the substrate and then dried at ambient temperature. Amperometric measurements were performed at different ammonia gas concentrations (1 to 500 ppb). The I-V characteristics were registered and some interfering gases were studied (NO2, ethanol, and acetone). The gas samples were prepared in a custom setup and were diluted with dry nitrogen gas. Electrospun nanofibers of PANI-RGO composite demonstrated an enhancement in NH3 gas detection when comparing with only electrospun PANI nanofibers. Was visible higher range of resistance at concentrations from 1 to 500 ppb. It was also observed that the sensor had stable, reproducible and recoverable properties. Moreover, it had better response and recovery times. The new sensing material of the developed sensor demonstrated to be a good candidate for ammonia gas determination.

Deciding Kleene Algebra Terms Equivalence in Coq

This paper presents a mechanically verified implementation of an algorithm for deciding the equivalence of Kleene algebra terms within the Coq proof assistant. The algorithm decides equivalence of two given regular expressions through an iterated process of testing the equivalence of their partial derivatives and does not require the construction of the corresponding automata. Recent theoretical and experimental research provides evidence that this method is, on average, more efficient than the classical methods based on automata. We present some performance tests, comparisons with similar approaches, and also introduce a generalization of the algorithm to decide the equivalence of terms of Kleene algebra with tests. The motivation for the work presented in this paper is that of using the libraries developed as trusted frameworks for carrying out certified program verification.