SENSITIVITY ANALYSIS OF TRACK VIBRATIONS DUE TO VERTICAL STIFFNESS VARIATION IN HIGH-SPEED RAILWAYS

High speed trains, when crossing regions with abrupt changes in vertical stiffness of the track and/or subsoil, may generate excessive ground and track vibrations. There is an urgent need for specific analyses of this problem so as to allow reliable esimates of vibration amplitude. Full understanding of these phenomena will lead to new construction solutions and mitigation of undesirable features. In this paper analytical transient solutions of dynamic response of one-dimensional systems with sudden change of foundation stiffness are derived. Results are expressed in terms of vertical displacement. Sensitivity analysis of the response amplitude is also performed. The analytical expressions presented herein, to the authors’ knowledge, have not been published yet. Although related to one-dimensional cases, they can give useful insight into the problem. Nevertheless, in order to obtain realistic response, vehicle- rail interaction cannot be omitted. Results and conclusions are confirmed using general purpose commercial software ANSYS. In conclusion, this work contributes to a better understanding of the additional vibration phenomenon due to vertical stiffness variation, permitting better control of the train velocity and optimization of the track design.

Catástrofes naturais em saúde pública : impactos e planos de emergência : caso de estudo : São Miguel-Açores

RESUMO - Nos últimos anos, as catástrofes naturais têm sido a causa frequente de problemas de Saúde Pública; além disso representam um sério obstáculo ao desenvolvimento das comunidades atingidas, na medida em que consomem ponderáveis recursos para a mitigação dos danos sofridos. Pode-se dizer que não existe nenhum país que não esteja exposto ao risco de catástrofes naturais, tais como Sismos, Tsunamis, Erupções Vulcânicas, Movimentos de Vertentes, Ciclones Tropicais, Ondas de Frio e de Calor, Secas e Inundações, e como tal, este é um problema global emergente. Como, actualmente, é impossível prever e controlar a ocorrência destes fenómenos, as acções humanas têm de ser direccionadas para a implementação de soluções que possam mitigar e/ou prevenir o seu impacto na sociedade. A integração do lugar, do espaço e do tempo na Saúde Pública, como componentes de investigação relativas aos problemas da população, são uma ferramenta metodológica importante no auxílio do planeamento, monitorização e avaliação das acções em saúde. O que está em causa neste estudo é o pensar, o preparar e o adaptar os nossos territórios e populações a cenários de crise que podem aparecer sem aviso prévio. Este trabalho é, sobretudo, uma forma de pensar e planear o futuro numa lógica de adaptação e valorização do território, construindo referenciais de suporte à acção. Assim, a finalidade deste estudo é contribuir para melhorar/aperfeiçoar a resposta perante novas situações de catástrofe natural, através da percepção e caracterização de situações anteriores de catástrofes naturais a que a Ilha de São Miguel, nos Açores, esteve sujeita nos últimos vinte e seis anos, através da construção e análise de cartas de localização de risco, caracterização da população em risco e da avaliação dos respectivos Planos de Emergência. ---------------------- ABSTRACT - In the last years, the natural disasters have been the frequent cause of Public Health problems and additionally they represent a serious obstacle to the development of the communities affected, in so far as they consume ponderable resources to the mitigation of the damages. It is possible to be said that there is not any country that is not exposed to the risk of natural disasters such as earthquakes, tsunamis, volcanic eruptions, landslides, tropical cyclones, waves of heat and coldness, droughts and floods, and as such, this is an emerging global problem. As it is now impossible to predict and control the occurrence of these phenomena, human actions must be directed to implement solutions that can mitigate and / or prevent their impact on society. The integration of place, space and time on Public Health, as part of research on problems of the population, are an important methodological tool to aid planning, monitoring and evaluation of activities in health. The main issue in this study is to think, prepare and adapt our territories and populations to crisis scenarios that may occur without notice. This work is mainly a way of thinking and planning ahead in a logic of adapting and improving the area, building frameworks to support the action. Thus, the purpose of this study is to contribute to improve / optimize the answer for new natural disaster situations, through the perception and characterization of previous situations of natural catastrophes that the Island of São Miguel, in the Azores, has been subject in the last twenty six years, through the construction and analysis of risk maps, characterization of the population in risk and of the evaluation of the respective Plans of Emergence.

A tutela preventiva da responsabilidade civil

The contemporary society is characterized by high risks. Today, the prevention of damages is as important as compensation. This is due to the fact that the potentiality of several damages is not in line with compensation, because often compensation proves to be impossible. Civil law should be at the service of the citizens, which explains that the heart of the institution of non-contractual liability has gradually moved towards the victim's protection. It is requested from Tort law an active attitude that seeks to avoid damages, reducing its dimension and frequency. The imputation by risk proves to be necessary and useful in the present context as it demonstrates the ability to model behaviors, functioning as a warning for agents engaged in hazardous activities. Economically, it seeks to prevent socially inefficient behaviors. Strict liability assumes notorious importance as a deterrent and in the dispersion of damage by society. The paradigm of the imputation founded on fault has proved insufficient for the effective protection of the interests of the citizens, particularly if based in an anachronistic vision of the concept of fault. Prevention arises in several areas, especially in environmental liability, producer liability and liability based on infringement of copyright and rights relating to the personality. To overcome the damage as the gauge for compensation does not inevitably mean the recognition of the punitive approach. Prevention should not be confused with reactive/punitive objectives. The deterrence of unlawful conduct is not subordinated to punishment.

Accumulation, responses and genotoxicity of trace elements in octopus vulgaris

Dissertação apresentada para obtenção do Grau de Doutor em Bioquímica pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Landslide susceptibility assessment in Karanganyar regency - Indonesia - Comparison of knowledge-based and Data-driven Models

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Image processing methodology for assessment of drilling induced damage in CFRP

Dissertação para obtenção do Grau de Mestre em Engenharia Mecânica

Clearing the cloudy crystal balls: Hybrid modelling for energy and climate change mitigation scenarios – A case study for Portugal

Dissertação para obtenção do Grau de Doutor em Ambiente

Precast concrete wall-foundation connection. Development of a seismic dissipative connection

Seismic events are a major factor to consider in structural design of buildings in many countries. With the purpose of saving lives, most of the design codes lead to structural solutions that withstand large seismic actions without collapsing, but without taking into account a possible usage of the structures after the earthquake. As a result, it is necessary to consider the time needed to repair/retrofit the damaged structures (i.e. the downtime) since this period of inactivity may result in huge financial implications for the occupants of the buildings. In order to minimise the damages and simplify repair operations, structural solutions with rocking systems and negligible residual displacements have been developed during the last two decades. Systems with precast concrete rocking walls were studied with the aim of investigat- ing suitable and convenient structural alternatives to minimise the damage in case of an earthquake. Experimental, numerical and analytical analyses on post-tensioned solutions, with and without energy dissipation devices, were carried out in this research. The energy dissipation devices were made from steel angles that were further developed during the research. Different solutions for these devices were experimentally tested under cyclic loading and the results are presented. Numerical and analytical work on steel angles was also carried out. Regarding the concrete rocking wall systems, two concrete rocking wall systems were studied: post-tensioned walls and post-tensioned walls with energy dissipation devices. In the latter, the solution was to fix them externally to the wall, allowing their easy replacement after an earthquake. It is shown that the dissipaters are a viable solution for use in precast concrete rocking wall systems. A building case study is presented. The comparison between a traditional monolithic system and a hybrid solution was carried out, allowing the evaluation of the efficiency of the solution that was developed.

Resilience of logistic service providers facing a port strike: a case study

The purpose of this thesis is to study the impact of a port strike on companies that perform as logistic service providers in a supply chain (SC), here denominated 3PL (third-party logistic providers). These companies are highly dependent on ports to perform their activity, since they provide international services. Consequently, a disruption in a port can seriously impair their business. A stevedores’ strike is one of the possible disruptions that can affect ports. This study aims to analyze the negative effects caused by this disruption, and what strategies 3PLs may implement in order to keep their performance levels stable and have a quick recovery time. Within this objective, the first step will be to establish a theoretical context about the maritime port’s sector and 3PLs in a SC context, to then expand the concept of a resilient SC, and finally to develop a theoretical framework in order to better contextualize the case study. Subsequently, the impact of a port strike will be quantified by using a case study comprising three companies, covering the areas of land and sea distribution and port operations. Information from primary sources was assembled in two phases: first via e-mail and, in a second phase, through a personal interview. The information from secondary sources was obtained through television news, internet and conferences, enabling its cross-analysis. Finally, by analyzing the collected data, it will be possible to draw conclusions about the measures carried out by each company to minimize the negative effects of the strike, thus contributing to a more resilient SC. As a conclusion, a stevedores’ strike will create a snow-ball of negative effects in the SC, degrading all relevant KPIs (key performance indicators) of the 3PLs under study. No mitigation and contingency strategies available proved really effective to reduce the negative effects of a port strike disruption.

Biological colonization on majolica glazed tiles: biodeterioration, bioreceptivity and mitigation strategies

The impact of microbial activity on the deterioration of cultural heritage is a well-recognized global problem. Glazed wall tiles constitute an important part of the worldwide cultural heritage. When exposed outdoors, biological colonization and consequently biodeterioration may occur. Few studies have dealt with this issue, as shown in the literature review on biodiversity, biodeterioration and bioreceptivity of architectural ceramic materials. Due to the lack of knowledge on the biodeteriogens affecting these assets, the characterization of microbial communities growing on Portuguese majolica glazed tiles, from Pena National Palace (Sintra, Portugal) and another from Casa da Pesca (Oeiras, Portugal) was carried out by culture and molecular biology techniques. Microbial communities were composed of microalgae, cyanobacteria, bacteria and fungi, including a new fungal species (Devriesia imbrexigena) described for the first time. Laboratory-based colonization experiments were performed to assess the biodeterioration patterns and bioreceptivity of glazed wall tiles produced in laboratory. Microorganisms previously identified on glazed tiles were inoculated on pristine and artificially aged tile models and incubated under laboratory conditions for 12 months. Phototrophic microorganisms were able to grow into glaze fissures and the tested fungus was able to form oxalates over the glaze. The bioreceptivity of artificially aged tiles was higher for phototrophic microorganisms than pristine tile models. A preliminary approach on mitigation strategies based on in situ application of commercial biocides and titanium dioxide (TiO2) nanoparticles on glazed tiles demonstrated that commercial biocides did not provide long term protection. In contrast, TiO2 treatment caused biofilm detachment. In addition, the use of TiO2 thin films on glazed wall tiles as a protective coating to prevent biological colonization was analysed under laboratorial conditions. Finally, conservation notes on tiles exposed to biological colonization were presented.