Railway track condition assessment at network level by frequency domain analysis of GPR data

The railway track system is a crucial infrastructure for the transportation of people and goods in modern societies. With the increase in railway traffic, the availability of the track for monitoring and maintenance purposes is becoming significantly reduced. Therefore, continuous non-destructive monitoring tools for track diagnoses take on even greater importance. In this context, Ground Penetrating Radar (GPR) technique results yield valuable information on track condition, mainly in the identification of the degradation of its physical and mechanical characteristics caused by subsurface malfunctions. Nevertheless, the application of GPR to assess the ballast condition is a challenging task because the material electromagnetic properties are sensitive to both the ballast grading and water content. This work presents a novel approach, fast and practical for surveying and analysing long sections of transport infrastructure, based mainly on expedite frequency domain analysis of the GPR signal. Examples are presented with the identification of track events, ballast interventions and potential locations of malfunctions. The approach, developed to identify changes in the track infrastructure, allows for a user-friendly visualisation of the track condition, even for GPR non-professionals such as railways engineers, and may further be used to correlate with track geometric parameters. It aims to automatically detect sudden variations in the GPR signals, obtained with successive surveys over long stretches of railway lines, thus providing valuable information in asset management activities of infrastructure managers

Dynamic Behavior in Transition Zones and Long-Term Railway Track Performance

This work was conducted in the framework of the TC202 national committee of the Portuguese Geotechnical Society (SPG) Transportation Geotechnics, in association with the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGETC202). Publisher Copyright: © Copyright © 2021 Paixão, Varandas and Fortunato.Transition zones between embankments and bridges or tunnels are examples of critical assets of the railway infrastructure. These locations often exhibit higher degradations rates, mostly due to the development of differential settlements, which amplify the dynamic train-track interaction, thus further accelerating the development of settlements and deteriorating track components and vehicles. Despite the technical and scientific interest in predicting the long-term behavior of transition zones, few studies have been able to develop a robust approach that could accurately simulate this complex structural response. To address this topic, this work presents a three-dimensional finite element (3D FEM) approach to simulate the long-term behavior of railway tracks at transition zones. The approach considers both plastic deformation of the ballast layer using a high-cycle strain accumulation model and the non-linearity of the dynamic vehicle-track interaction that results from the evolution of the deformed states of the track itself. The results shed some light into the behavior of transition zones and evidence the complex long-term response of this structures and its interdependency with the transient response of the train-track interaction. Aspects that are critical when assessing the performance of these systems are analyzed in detail, which might be of relevance for researchers and practitioners in the design, construction, and maintenance processes.publishersversionpublishe

Um : novo paradigma sobre o contrato de trabalho a termo em Angola

O presente estudo subordina-se à análise do novo regime do contrato de trabalho a termo, aprovado pela nova Lei Geral do Trabalho, a Lei 7/15, de 15 de Junho, justificada pela necessidade do aumento de geração de empregos com vista à dinamização da economia angolana. Entretanto, a nossa pesquisa procura demonstrar que os principais motivos para a alteração da Lei Geral do Trabalho devem ser confrontados com os elementos considerados entraves à dinamização da economia angolana. Para além disso, a análise problemática do regime jurídico do contrato de trabalho a termo implica a consideração da evolução legislativa, havendo a necessidade de percorrer os regimes anteriores das leis de trabalhado em vigor desde 1981 a 2015. Segue-se a análise do direito comparado dos sistemas juslaborais da Comunidade dos Países de Língua Portuguesa, através do estudo dos requisitos de validade da contratação a termo, da sua duração, renovação, conversão, sucessão, cessação e seus efeitos. Finalmente, a atenção ao regime jurídico do contrato de trabalho a termo é conduzida à consideração da necessidade da conformação com os valores da estabilidade e da segurança no trabalho, do tratamento mais favorável e da intangibilidade dos direitos adquiridos pelo trabalhador, conquistados no domínio laboral.The present study is subordinated to the analysis of the new regime of the fixed-term employment contract, approved by the new General Labor Law, Law 7/15, of June 15, justified by the need to increase employment generation in order to stimulate the Angolan economy. However, our research seeks to demonstrate that the main reasons for the amendment of the General Labor Law should be confronted with the elements considered as obstacles to the growth of the Angolan economy. So, the problematic analysis of the legal regime of the fixed-term contract implies consideration of legislative developments and there is a need to go through the previous labor law regimes in force from 1981 to 2015. The analysis of the comparative law of the labor law systems of the Community of Portuguese-speaking Countries is based on the study of the validity requirements of the fixed-term contract, its duration, renewal, conversion, succession, termination and its effects. Finally, attention to the legal regime of the fixed-term employment contract is taken into consideration in the need to conform with the values of stability and security at work, the most favorable treatment and the intangibility of the rights acquired by the worker, obtained in the labor field

Cytomegalovirus Reactivation in Patients with Sepsis in an Intensive Care Unit in Portugal

INTRODUCTION: In the last few years, cytomegalovirus reactivation has been considered an aggravating factor for septic patients in Intensive Care units. The main objectives of this study were to determine cytomegalovirus reactivation in patients with a diagnosis of sepsis admitted to an intensive care unit, and whether this reactivation was related to the evolution of the patient's clinical condition. MATERIAL AND METHODS: The detection of cytomegalovirus DNA was performed by real-time polymerase chain reaction and the concentration of nine cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL- TNF-α, and INFγ) were determined by a Multiplex ELISA technique. RESULTS: Eight of 22 septic patients (36.3%) from the Intensive Care Unit of the Hospital da Luz had cytomegalovirus reactivation. No association was found between cytomegalovirus reactivation and gender, age, length of Intensive Care unit stay, duration of mechanical ventilation, and patient death. No significant differences were found in cytokine concentrations in patients with and without reactivation. However, patients with cytomegalovirus reactivation had a longer hospital stay from Intensive Care unit entry to hospital discharge or patient death (p = 0.025). DISCUSSION: Despite the low sampling rate, the present study suggests that reactivation is a frequent event in patients diagnosed with sepsis and may be related to prolonged hospital stay in these patients. CONCLUSION: The overall analysis of the results obtained and the literature review do not support the concept that cytomegalovirus monitoring should be implemented in routine practice, but it seems prudent to wait for further randomized trials using antiviral prophylaxis, before assuming a definitive attitude towards the role of cytomegalovirus in sepsis.publishersversionpublishe

The skin temperature under multilayered bandages during exercise

Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

Impacto do Working from Anywhere no comportamento inovador do trabalhador : estudo exploratório em empresas intensivas em conhecimento

Mestrado Bolonha em Gestão e Estratégia IndustrialO objetivo deste trabalho passa por analisar o impacto que o Working From Anywhere tem no comportamento inovador do trabalhador. Tendo em conta que esta é uma relação pouco estudada na literatura foram realizadas entrevistas a trabalhadores de cinco empresas intensivas em conhecimento, com o intuito de colmatar esta lacuna no estudo sobre inovação. Os resultados obtidos mostram que o Working From Anywhere aumenta a capacidade dos trabalhadores para criarem ideias novas e úteis, através de um acréscimo de autonomia no trabalho, e que a capacidade dos trabalhadores para implementar novas ideias pode ser prejudicada caso percecionem existir uma deterioração do feedback que recebem dos colegas. Os resultados mostram também que a falta de interação social característica num ambiente de escritório pode influenciar o compromisso afetivo, feedback dos colegas e apoio dos colegas. Em particular, os trabalhadores sentem que a falta de interação social diminui a sua ligação emocional à empresa.This study aims to analyse the impact that Working From Anywhere has on employee's innovative behaviour. Given that this relationship is not fully covered in the literature, interviews were carried out with workers from five knowledge-intensive companies in order to fill this gap in the study on innovation. The results obtained show that Working From Anywhere increases the worker's ability to create new and useful ideas, through an increase in autonomy at work, and that the worker's ability to implement new ideas can be impaired if they perceive that there is a deterioration of feedback they receive from their co-workers. The results also show that the lack of social interaction prevalent in an office environment can influence affective commitment, co-worker feedback and co-worker support. In particular, workers feel that the lack of social interaction diminishes their emotional attachment to the company.info:eu-repo/semantics/publishedVersio

Compras públicas compartilhadas: um estudo de caso comparando modelos de compras públicas eletrônicas adotados no Brasil, no Chile e nos Estados Unidos

A dissertação trata sobre o tema “Compras Governamentais Compartilhadas”. A pesquisa faz uso da metodologia de estudo de múltiplos casos com o objetivo de apresentar uma análise comparativa de modelos de compras adotados no Brasil, no Chile e nos Estados Unidos. Os casos escolhidos foram o Registro de Preços Nacional, executada pelo FNDE, no Brasil; o Convenios Marco, executada pelo ChileCompra, no Chile; e o Federal Marketplace Strategy, executada pelo GSA, nos Estados Unidos. O trabalho envolveu pesquisa bibliográfica, análise documental e análise de bases de dados públicas, principalmente do Comprasnet, OCDE e World Bank. As evidenciais mobilizadas permitem afirmar que as três políticas públicas apresentam um conjunto de fatores críticos de sucesso em comum, dentre eles o foco no redesenho dos processos de trabalho, a capacitação dos servidores públicos e o desenvolvimento de relacionamento institucional com fornecedores. Para uma agenda futura de pesquisa é importante atentar para dois fatores comuns aos modelos chileno e norte-americano que aprimoraram positivamente seus processos de contratação, são eles: a utilização de unidades centralizadas de compras públicas (central purchasing bodies) e a divisão do processo de compras em uma fase centralizada, voltada para a formalização do contrato, e uma fase descentralizada, focada na aquisição efetiva de bens e serviços pelos diversos órgãos públicos. Ao final, concluiu-se que os três modelos de políticas de compras analisados inovaram positivamente o processo de contratação e trouxeram benefícios significativos em termos de eficiência e qualidade para seus usuários.137 páginasGovernançaLogística e Compras Pública

Arquitetura floral do morangueiro em cultura protegida e em substrato na região do Algarve

Mestrado em Engenharia Agronómica / Instituto Superior de Agronomia. Universidade de LisboaA possibilidade de se estimar o grau de desenvolvimento da planta de morangueiro e prever o seu potencial de floração e de frutificação tem particular importância por permitir ao produtor planear e gerir de forma mais eficiente os recursos disponíveis e actuar de forma mais eficaz. O objectivo deste trabalho foi avaliar a arquitetura das plantas de morangueiro provenientes do viveiro e ao longo do ciclo cultural de duas cultivares de dias curtos (DC), Dream/planta tray e Calinda/planta de raiz nua e de uma cultivar indiferente (ID) Harmony/planta mote, num sistema de produção em cultura de substrato conduzido em macrotúneis, na região de Moncarapacho (Algarve). Paralelamente pretendeu-se determinar a época e a quantidade de floração e consequente produtividade. As plantas tray da cv. Dream e as plantas mote da cv. Harmony diferenciaram maior número de primórdios florais (inflorescências e flores) no viveiro que as plantas de raiz nua da cv. Calinda. Verificou-se um aumento gradual do número de primórdios florais ao longo do ciclo, com maior taxa de diferenciação floral nas cultivares Dream/tray e Harmony/mote, antevendo-se, assim, o maior potencial de produção destas duas cultivares em relação à Calinda/raiz nua, o que veio a confirmar-se posteriormente. O padrão de evolução dos primórdios florais foi semelhante nas duas cultivares de DC, com decréscimo da diferenciação floral no final do ciclo, enquanto na cultivar ID a diferenciação floral não cessou. A Dream/tray revelou ser uma cultivar precoce e em conjunto com a Harmony/mote apresentaram uma maior produtividadeN/

Operational performance and losses in mechanized soybean harvesting as a function of field shape

Information on the capacity, operational efficiency, and performance of the harvester is very important in the management of agricultural mechanized systems, influencing decisions made with the aim of optimization. This study aimed to evaluate times, movements, and quality of mechanical soybean harvest operations in different shapes of the plots. Operational performance parameters of the harvester and variables representative of the agronomic aspects of the crop were used as indicators through statistical process control tools. Mechanized harvesting was carried out at a farm located in Uberaba, Minas Gerais, and the experimental design was completely randomized, with 18, 28, and 24 repetitions in irregular, rectangular, and trapezoidal fields, respectively. The activities of the harvester (harvest, unloading, handling, and climate charts) were monitored. The indicators of quality for harvester performance were: forward speed, engine and cylinder rotation and concave opening. The losses were determined: on the platform, internal mechanisms, total and in relation to productivity. The managerial efficiency and shunt time presented better results for the trapezoidal and rectangular section, respectively. All quality indicators evaluated were within the limits of statistical control, characterizing quality and reliability of the soybean harvesting operation.Information on the capacity, operational efficiency, and performance of the harvester is very important in the management of agricultural mechanized systems, influencing decisions made with the aim of optimization. This study aimed to evaluate times, movements, and quality of mechanical soybean harvest operations in different shapes of the plots. Operational performance parameters of the harvester and variables representative of the agronomic aspects of the crop were used as indicators through statistical process control tools. Mechanized harvesting was carried out at a farm located in Uberaba, Minas Gerais, and the experimental design was completely randomized, with 18, 28, and 24 repetitions in irregular, rectangular, and trapezoidal fields, respectively. The activities of the harvester (harvest, unloading, handling, and climate charts) were monitored. The indicators of quality for harvester performance were: forward speed, engine and cylinder rotation and concave opening. The losses were determined: on the platform, internal mechanisms, total and in relation to productivity. The managerial efficiency and shunt time presented better results for the trapezoidal and rectangular section, respectively. All quality indicators evaluated were within the limits of statistical control, characterizing quality and reliability of the soybean harvesting operation

Effects of respiratory disease and age in quadriceps muscle mass: a pilot study with ultrasonography

No abstract available.publishe