Comportamento das interfaces solo - geossintético

Tese de mestrado integrado. Engenharia Civil. Faculdade de Engenharia. Universidade do Porto. 201

An Integrated Similarity Analysis of Anatomical and Physical Wood Properties of Tropical Species from India, Mozambique, and East Timor

Tropical species are highly valued timber sources showing a large diversity of wood characteristics. Since there are major concerns regarding the sustainability of these tropical species in many tropical regions, knowledge of the variability in wood properties is therefore a valuable tool to design targeted exploitation and to enlarge the wood resources base, namely by identifying alternatives for CITES-listed species. In this study, 98 tropical wood species belonging to 73 genera from India, Mozambique, and East Timor were investigated regarding wood anatomy and physical properties. Numerical taxonomy, by means of cluster analysis and principal component analysis grouped species with anatomical and physical similarities from different geographical origins. In addition to wood density, ray and vessel characteristics as well as wood moisture and wood shrinkage properties explained the main variability of these species. The contribution of wood color patterns was highlighted as consistently separating the Mozambique woods. A distinct geographical pattern was not observed, reinforcing that species from India, Mozambique, and East Timor show similar anatomical and physical wood properties, which could be useful to increase timber trade diversity. The multivariate analysis showed that species from Mozambique, such as Morus mesozygia, and Millettia stuhlmannii and Swartzia madagascariensis, could be alternatives for the CITES-listed species Cedrela odorata and Dalbergia melanoxylon, respectivelyinfo:eu-repo/semantics/publishedVersio

Improved performance of geosynthetics enhanced ballast: laboratory and numerical studies

Ballasted rail tracks form one of the most important worldwide transportation modes in terms of traffic tonnage, serving the needs of bulk freight and passenger movement. High impact and cyclic loads can cause a significant deformation leading to poor track geometry. In order to mitigate these problems, the concept of the inclusion of geosynthetics in rail tracks is introduced. This paper presents the current state-of-the-art knowledge of rail track geomechanics, including results obtained from laboratory testing, field investigations and numerical modelling to study the load-deformation behaviour of ballast improved by geosynthetics. The shear stress-strain and deformation behaviour of geosynthetic-reinforced ballast are investigated in the laboratory using a large-scale direct shear test device, a track process simulation apparatus and a drop-weight impact testing equipment. Computational modelling using the discrete-element method is employed to simulate geosynthetic-reinforced ballasted tracks, capturing the discrete nature of ballast aggregates when subjected to various types of loading and boundary conditions. Discreteelement modelling is also used to conduct micromechanical analysis at the interface between ballast and geogrid, providing further insight into the behaviour of ballast subjected to cyclic loadings. These results provide promising approaches to incorporate into existing track design routines catering for future high-speed trains and heavier heavy hauls

The anatomy as a tool for the identification of the bark of Pterocarpus angolensis and Terminalia sericea

Pterocarpus angolensis and Terminalia sericea are two African species with medicinal potential. Despite the importance of their bark as a powerful astringent to treat various diseases it is poor described. In order to provide referential information for correct identification and standardization of the plant material, bark samples from each two species were collected and analyzed under light and electron microscopy. Some important anatomical features to identification were: the sclerenchyma tissue mostly in form of fibre-sclereids and the large secretory cells arranged in conspicuous rows or tangential bands in the conducting phloem in P. angolensis; the crystalliferous cells arranged in very regular tangential rows (druses) and the occurrence of large crystal cells near or including the tangential fibre bundles in T. sericea bark.The results obtained show that the anatomy of the bark can be used as an important subsidy in identification and standardization of the studied species contributing the scientific knowledge for more effective forms of scrutiny in preventing commercial adulteration of species

O ensino e a aprendizagem da Física Experimental do 10º ano de escolaridade: uma abordagem tecnológica

Dissertação de mestrado em Ciências – Formação Contínua de Professores (área de especialização em Física e Química)Tudo o que se faz na sala de aula contribui para a formação dos alunos como futuros cidadãos capazes de resolver desafios, no campo pessoal, social ou mesmo profissional. A forma como concebemos a nossa prática letiva, o modo como incentivamos os alunos, os materiais que utilizamos, são importantes para que estes invistam na sua aprendizagem. Contudo, o elevado número de alunos atribuído a cada professor, o pouco tempo disponível para se permitir que cada aluno prossiga no seu ritmo de aprendizagem, são um entrave para que todos os alunos atinjam o mesmo nível de conhecimentos e ao mesmo tempo. A desmotivação dos alunos para a aprendizagem das Ciências em geral e da Física em particular, associada aos elevados níveis de insucesso levam os alunos a não optarem pela sua aprendizagem. Com poucos incentivos e com poucos recursos muitas vezes deixamonos levar pela inércia e pela tradição. Mas são as dificuldades que também servem de desafio – um desafio constante na busca de estratégias motivacionais que possam alterar esta situação e ajudar os alunos a querer aprender. Este estudo pretende mostrar as potencialidades da tecnologia no ensino da Física, nomeadamente o uso do Lab Cradle, de sensores e do sistema TI-Navigator associados à unidade portátil (calculadora gráfica) TI-Nspire-CX. Pretende-se igualmente mostrar que estas tecnologias podem contribuir para que o trabalho laboratorial e os conceitos teóricos a ele subjacentes sejam melhor compreendidos pelos alunos. Com este trabalho pretende-se também mostrar que é possível desenvolver nos alunos uma postura ativa na construção da sua própria aprendizagem. Com a tecnologia TI-Navigator quer as aprendizagens dos alunos quer a sua avaliação ficam facilitadas. É uma tecnologia que permite ao professor a monotorização permanente do trabalho desenvolvido por cada aluno quer na aquisição de dados, quer no seu processamento, análise e discussão. Mostra--se ainda que, com esta tecnologia, é possível elaborar questionários que podem orientar o professor no sentido de diagnosticar a existência de conceções alternativas nos alunos ou mesmo de verificar o nível de consolidação de conhecimentos, facilitando a sua correção e a análise estatística dos resultados. Os resultados da implementação desta metodologia de ensino são promissores. Os alunos mantiveram-se motivados até ao final das aulas e revelaram-se satisfeitos com esta tecnologia que dizem ser de fácil utilização e que consideram uma ajuda quer na aprendizagem quer na avaliação.All that is done in a classroom context contributes to the development of students, as future citizens, capable of solving challenges on a personal, social, or even on a professional basis. The way our teaching is perceived, the way our students are encouraged, the materials that are used, all is important for student investment in learning. However, the high average number of students allotted per teacher and the little time available for each student to proceed at his or her own learning pace, are impediments for each and every student to attain the same level at the same time. Students’ lack of motivation for the learning of Science in general, and Physics in particular, associated to high levels of underachievement leads students do not opt for their learning. With little incentives and resources, passivity and tradition carry teachers away. But, difficulties are a challenge – a constant challenge in search of motivational strategies that will enable change and allow students to want to learn. This study intends to demonstrate the potential of technology in the teaching of Physics, namely the use of Lab Cradle, sensors, and the TI-Navigator system associated to the portable unit (graphic calculator) TI-Nspire-CX. It also intends to show that such technology used in laboratorial work, and its underlying theoretical concepts, can contribute to a better understanding of students. This research study also shows that it is possible for students to have an active role in the construction of their own learning. TI-Navigator facilitates student learning and assessment. It is a technology that enables the teacher to permanently monitor the work developed by each student, whether in the acquisition of data, whether in its processing, analysis and discussion. It also demonstrates that by using this technology it is possible to elaborate questionnaires which can orientate the teacher in the diagnosis of students’ alternative conceptions, or verify the level of knowledge consolidation, facilitating its correction and the statistical analysis of results. The outcomes of the implementation of such teaching methodology are promising. Students keep motivated during the entire lesson and claim to be satisfied with such technology, which they say is easy to use and consider to be an aid to learning and assessment

Xiloteca virtual - colecção de madeiras da India portuguesa

Congresso Florestal Nacional: A floresta e as gentes - Actas das ComunicaçõesCom base na colecção de amostras de madeira existente na xiloteca e respectiva laminoteca do Centro de Estudos de Tecnologia Florestal (IICT), apresenta-se uma base de dados de madeiras da Índia Portuguesa, que inclui 17 espécies xilógenas, selecionadas por serem das mais abundantes e com maior interesse em Goa. O objectivo deste trabalho é a criação de uma Xiloteca Virtual, que reuna toda a informação existente sobre as madeiras, prevendo-se uma série de interacções que possibilitem dar rápida resposta a questões concretas do utilizador, como sejam a identificação botânica, as propriedades anatómicas e físicas da madeira e ainda os diferentes usos. Para cada espécie indica-se a família, o nome botânico, os nomes indígenas, a distribuição geográfica e as características da madeira. A caracterização da madeira inclui os aspectos gerais tais como, a cor, o desenho, a textura, o estudo anatómico, com as descrições macro e microscópicas e as propriedades físicas (densidade e retracção) com interesse na identificação e utilização final da madeira. Exemplifica-se o trabalho com saídas tipo, referente ao aspecto geral da madeira, propriedades anatómicas e físicas, fotomicrografias e possíveis interacções

Characterization Of Pcl And Chitosan Nanoparticles As Carriers Of Enoxaparin And Its Antithrombotic Effect In Animal Models Of Venous Thrombosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This study was based on the preparation, characterization, and animal in vivo experiments performed to evaluate nanoparticles of poly(epsilon-caprolactone) (PCL) and chitosan as carriers of enoxaparin. Thenanoparticles were characterized and presented satisfactory results in terms of size, polydispersity, and encapsulation efficiency. Anticoagulant activity of the nanoparticles was maintained for 14 hours when the administration was subcutaneous; however no activity was observed after oral administration. There was a significant reduction in thrombus size, in vivo, for both free and encapsulated enoxaparin in comparison with the control group after subcutaneous administration. Oral administration results however were indifferent. In conclusion, the double emulsion method w/o/w was efficient for enoxaparin encapsulation, producing spherical nanoparticles with high encapsulation efficiency. For in vivo studies, the encapsulated enoxaparin showed a sustained anticoagulant activity for a higher period of time compared to free enoxaparin, with an antithrombotic effect when administered subcutaneously.FAPESPCNPqBrazilian Network on Nanocosmetics (MCT/CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Ordem e desordem no processo de implantação de Palmas: a capital projetada do Tocantins

In view of the organization and production of urban space implemented in Palmas, the projected capital of Tocantins state, Brazil, it becomes necessary to address the complex relation between determinate and indeterminate actions. Within this logic of interpretation, Palmas’ urban space comes through as the product of three types of order: an intentional order (determinacy), an spontaneous order (indeterminacy), and a changing order between the first two (indeterminacy).This paper aims to conciliate the seemingly contradictory process of a determinate urbanization – at first structured by planned attempts – which later gave way to the unpredictabilities and indeterminacies of the real world. This occurred mainly as a result of the arbitrariness of public authorities and the personal interests of land market agents, leading to a scenario marked by the political and economic hegemonization of the urban territory. Hence, this analysis of urban reality is guided by the complex relations between intentionality and spontaneity, determinacy and indeterminacy and, in short, between order and disorder. Diante dos processos de organização e produção do espaço urbano em Palmas, a capital projetada do Tocantins, valemo-nos da relação complexa entre ações marcadas por determinação e indeterminação. Nessa lógica de interpretação, define-se que o espaço urbano de Palmas é produto de três tipos de ordem: intencional (determinação), espontânea (indeterminação) e uma ordem cambiante entre elas. Este artigo visa conciliar esse aspecto, aparentemente contraditório, de uma urbanização determinada, a princípio, por tentativas planejadas, mas que cedeu a imprevisibilidades e indeterminações do mundo real, especialmente por arbitrariedades do poder público e interesses de agentes do mercado de terras, configurando um contexto marcado pela hegemonização político-econômica do território urbano. Portanto, esta possibilidade de análise da realidade urbana orienta-se pelas relações complexas entre o intencional e o espontâneo, o determinado e o indeterminado, e, por fim, entre a ordem e a desordem