369 research outputs found

    Argamassas multifuncionais para armazenamento de calor, despoluição do ar e auto-limpeza, processo para a sua preparação e utilização

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    Patente Portuguesa n.º PT 106935A presente invenção diz respeito a argamassas, para aplicação no revestimento interior e exterior de sistemas construtivos, que compreende misturas, em diferentes proporções, de microcápsulas de materiais de mudança de fase (PCM) e nanopartículas de dióxido de titânio, juntamente com um ou mais ligantes, à base de cal, cimento ou gesso, agregados, água e outros materiais auxiliares. A invenção diz também respeito a um processo para a elaboração das referidas argamassas por mistura prévia e homogeneização, em seco, dos componentes sólidos, com posterior mistura com água e homogeneização numa máquina misturadora. A argamassa de acordo com a invenção é utilizada no revestimento interior e exterior de sistemas construtivos, com o objectivo de poupar energia, melhorar a qualidade do ar e assegurar auto-limpeza.Fundação para a Ciência e a Tecnologia (FCT

    Análise visual dos dados educacionais voltada para o estudo de gênero nos cursos de Computação da Universidade de Brasília

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    Trabalho de conclusão de curso (graduação)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2018.O número de mulheres em cursos de tecnologia vem diminuindo com o passar dos anos, chegando em 2016 a menos de 20% do total do corpo estudantil do Departamento de Ciência da Computação da Universidade de Brasília. A utilização de visualizações auxilia na tomada de decisão para promover a entrada e a permanência de alunas nos cursos e, consequentemente, aumentar o número de mulheres no mercado de trabalho em áreas de tecnologia. Este trabalho emprega técnicas de visualização para analisar e identificar padrões no perfil de meninas nos cursos de graduação da área de tecnologia. Por isso,foram utilizadas técnicas de redução de dimensionalidade (PCA e t-SNE), Mapas de Calor e Gráficos de Coordenadas Paralelas para o processo de análise visual de dados, considerando a situação das estudantes em relação à UnB (ativas, desligadas ou graduadas). As visualizações obtidas revelaram que os dados possuem natureza não linear, sendo possível agrupar as meninas de acordo com a forma de saída. Neste trabalho, foi evidenciada a correlação existente entre as variáveis, sendo analisada mais profundamente a associação entre os períodos de entrada e de saída na Universidade, e a forma de saída desta.The number of women in technology courses has been decreasing over the years, reaching less than 20% of the total student body of the Department of Computer Science of the University of Brasília in the year of 2016. The use of visualization helps in the decision making, to promote the entrance and the permanency of female students in courses, thus increasing the number of women in the labor market in technology areas. This work uses visualization techniques to analyze and identify profile patterns in girls of undergraduate courses in the technology field. Dimensionality reduction tech- niques (PCA and t-SNE), HeatMap and Parallel Coordinates Graphics were used for the visual data analysis process, considering the students situation in relation to UnB (active, disconnected or graduated). The visualizations obtained revealed that the data have a non-linear nature, making it possible to join girls in groups according to their form of leaving the university. In this work, the existing correlations between variables were ev- idenced, being deeper analyzed the association between periods of entrance and leaving in the university and the way of leaving

    Papel de nano-aditivos na funcionalização de argamassas

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    A manutenção da qualidade do ar no interior dos edifícios é um dos aspetos mais relevantes da construção sustentável e tem forte impacto no nível de conforto dos utilizadores. A introdução de nano-aditivos em materiais de construção permite modificar propriedades fundamentais destes materiais convencionais, com o objetivo de proporcionar novas funcionalidades. Neste trabalho apresentam-se os resultados obtidos com o desenvolvimento de argamassas funcionais que pretendem melhorar a qualidade do ar interior e contribuir para a poupança energética dos edifícios. As formulações foram optimizadas com vista à sua aplicação em construção nova ou reabilitação

    Deep Convolutional Autoencoders as Generic Feature Extractors in Seismological Applications

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    The idea of using a deep autoencoder to encode seismic waveform features and then use them in different seismological applications is appealing. In this paper, we designed tests to evaluate this idea of using autoencoders as feature extractors for different seismological applications, such as event discrimination (i.e., earthquake vs. noise waveforms, earthquake vs. explosion waveforms, and phase picking). These tests involve training an autoencoder, either undercomplete or overcomplete, on a large amount of earthquake waveforms, and then using the trained encoder as a feature extractor with subsequent application layers (either a fully connected layer, or a convolutional layer plus a fully connected layer) to make the decision. By comparing the performance of these newly designed models against the baseline models trained from scratch, we conclude that the autoencoder feature extractor approach may only perform well under certain conditions such as when the target problems require features to be similar to the autoencoder encoded features, when a relatively small amount of training data is available, and when certain model structures and training strategies are utilized. The model structure that works best in all these tests is an overcomplete autoencoder with a convolutional layer and a fully connected layer to make the estimation

    Coevolution creates complex mosaics across large landscapes

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    The spatial distribution of populations can influence the evolutionary outcome of species interactions. The variation in direction and strength of selection across local communities creates geographic selection mosaics that, when combined with gene flow and genomic processes such as genome duplication or hybridization, can fuel ongoing coevolution. A fundamental problem to solve is how coevolution proceeds when many populations that vary in their ecological outcomes are connected across large landscapes. Here we use a lattice model to explore this problem. Our results show that the complex interrelationships among the elements of the geographic mosaic of coevolution can lead to the formation of clusters of populations with similar phenotypes that are larger than expected by local selection. Our results indicate that neither the spatial distribution of phenotypes nor the spatial differences in magnitude and direction of selection alone dictate coevolutionary dynamics: the geographic mosaic of coevolution affects formation of phenotypic clusters, which in turn affect the spatial and temporal dynamics of coevolution. Because the formation of large phenotypic clusters depends on gene flow, we predict that current habitat fragmentation will change the outcomes of geographic mosaics, coupling spatial patterns in selection and phenotypes1942217229We acknowledge the funding provided by the European Union Seventh Framework Programme (FP7/2007–2013; grant agreement 289384 [L.D.F.]), the São Paulo Research Foundation (grants 2009/54422-8 [P.R.G.], 2016/06054-3 [M.A.M.A.], and 2015/26989-4 [L.D.F.]), the National Council of Scientific and Technological Development (M.A.M.A. and P.L.-C.), and the National Science Foundation (DEB0839853 [J.N.T.]

    Properties of lime based thermal mortars

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    [Excerpt] Nowadays, major part of residential buildings electricity consumption is used for space heating and cooling, varying greatly during day and night and leading to differentiate tariffs. The shift, to off-peak periods, of this consumption presents a clear economical advantage and it can be achieved through energy thermal storage. Latent heat thermal energy storage, through the incorporation of PCM, presents the following advantages: narrow the gap between the peak and off-peak loads, levelling the electricity demand, decreasing the load on the network and eventual supply failure; reduce operation costs by shifting the electrical consumption from peak periods to off-peak periods; contribute to the interior thermal comfort in buildings, by using and storing solar energy (for space heating in winter) and storing natural cooling by ventilation at night during the summer, thus reducing electricity use for heating and cooling [1,2].The benefits to the comfort inside buildings appear during the change of the PCM. The transferences of energy that occur during the transitions solid-liquid and liquid-solid are generally the most used to help the acclimatization of the building. For that reason the PCM must be microencapsulated. The exterior of the microcapsules is made with a polymer [1,2]

    Novos materiais de construção com tecnologias avançadas

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    Este artigo pretende apenas dar um contributo, assinalando alguns exemplos em que se tem vindo a trabalhar e que refletem o uso de tecnologias avançadas na formulação e funcionalidade de materiais de construção tradicionais. Um exemplo claro é o uso de aditivos que induzem novas funções e que muitos deles pertencem ao grupo denominado como nanomateriais. A sua adição coloca quase sempre problemas de incorporação e que requerem um trabalho de ajuste das formulações e comportamentos no estado fresco ou endurecido. Este trabalho de investigação é muitas vezes essencial para a otimização das funções que se pretendem que os materiais de construção venham a demonstrar. Neste grupo de investigação, resultante da cooperação entre centros de I&D e empresas em projetos de colaboração diversos ao longo dos últimos anos, tem-se vindo a focar na introdução de novas funções em materiais de construção tradicionais, para que ganhem um papel ativo em domínios como o do conforto térmico ou da qualidade ambiental, dois pilares essenciais para uma construção mais sustentável

    Application of endograft to treat thoracic aortic pathologies: A single center experience

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    PurposeTo evaluate our experience of thoracic endoluminal graft (ELG) repair of various thoracic aortic pathologies using a commercially available device approved by the Food and Drug Administration. Our patient population includes patients eligible for open surgical repair and those with prohibitive surgical risk.MethodsFrom March 1998 to March 2006, endovascular stent repair of the thoracic aorta was performed on 406 patients with 324 patients (median age 72; 200 male) receiving the Gore Excluder endograft. Patient demographics, procedural characteristics, complications, including endoleak, spinal cord ischemia, and mortality, were retrospectively reviewed during follow-up. All patients were followed with chest computer tomography at 6 months and yearly. Statistical analysis was performed utilizing the SPSS Windows 11.0 program. Logistic regression (univariate) analysis used to identify risk factors for paraplegia; analysis of variance (ANOVA) for endoleak distribution; and χ2 used to analyze variables. Survival analysis was done using SAS version 9.1 (SAS Institute, Cary, NC).ResultsThree hundred twenty-four patients were treated with Gore Excluder graft between March 1998 and March 2006. One hundred fifty-seven patients (48.5%) had atherosclerotic aneurysms, 82 (25.3%) had dissections type B (DTB), 34 (10.5%) had penetrating ulcers (PU), 26 (8.0%) with pseudoaneurysms (PSA), 11 (3.4%) had transections (MVAT), 9 (2.8%) aorto-bronchial fistulas (AoBF), 4 (1.2%) embolization, and 1 (0.3%) aorto-esophageal fistula (AoEF). Preoperative aneurysm sac size in TAA ranged from 5 to 12 centimeters, average size 6.3 cm. Sac shrinkage occurred in 65% (102 of 157) of patients. Average postoperative sac size of 5.4 cm in a mean follow-up of 20.4 months. One hundred cases (31.5%) were nonelective; 49 (15.1%) were ruptures. Overall complication was 22.7%, 14.2% (46) in elective cases and 8.5% (28) in nonelective cases. Paraplegia occurred in five (1.5%) patients and paresis in three (0.9%); two of the latter improved and one resolved completely prior to discharge. Incidence of paraplegia was statistically significant (P value < .05) with retroperitoneal approach, perioperative blood loss greater than 1000 cc, and aortic coverage greater than 40 cm. Early endoleaks included 18 (5.5%) type I, four (1.2%) type II, and two (0.6%) type III. Thirty-day mortality was 5.5% (18 related deaths, including three intraoperative deaths). A log rank test did not find statistical differences in actuarial survival with 30-day related mortality between TAA and other pathologies (P = .29) or between DTB and other pathologies (P = .97). Late mortality was 9.6% with 31 unrelated deaths. Follow-up ranged between 1 month and 70 months, average 17 months.ConclusionsEndoluminal grafting is a feasible alternative to open surgical repair for thoracic aortic pathologies. After more than 300 cases, 30-day morbidity and mortality compares favorably with open repair. Paraplegia remains low as a complication and increases in incidence with retroperitoneal approach, increased perioperative blood loss, and increased aortic coverage

    Organic consequences of ileal transposition in rats with diet-induced obesity

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    INTRODUCTION: The clinical management of metabolic syndrome - especially diabetes mellitus type 2 - is notoriously complex due to the progressive nature of this disease. At present, there is a need for a surgical procedure that is effective for the treatment of diabetes mellitus type 2, even in non-obese individuals. The isolated ileal transposition theory could lead to an effective alternative therapy. This intervention has not yet been performed in humans, and there are no reports of its use in an experimental model of diet-induced metabolic syndrome.&#xd;&#xa; OBJECTIVES: The objective of this study is to evaluate the physiological effects of ileal transposition in rats with diet-induced metabolic syndrome. The effects of this procedure on glucose and lipid metabolism will be assessed. &#xd;&#xa;METHODS: Forty 12-week-old male rats (albino Rattus norvegicus, Wistar, 2BAW, heterogeneous) will be divided into four groups of 10 animals each: the ileal transposition group (TG) comprising animals on a hypercaloric-hyperlipidic diet; the sham group (SG) containing animals that receive the same diet and undergo the sham surgery; control group 1 (CG1), which will receive a hypercaloric-hyperlipidic diet and will not undergo surgery; and control group 2 (CG2), which will consume standard feed and will not undergo surgery. The surgeries will be performed in 20-week-old animals. Blood samples for laboratory testing will be collected from 12-week-old animals on the day of surgery and after eight postoperative weeks, following determination of the weights of the animals and the administration of anesthesia. The levels of serum glucose, insulin, triglycerides, total cholesterol and fractions, glucagon-like peptide-1, C-peptide and glycated hemoglobin will be assessed in all of the animals. The insulin tolerance test will be performed using PRISMA software, and insulin resistance will be calculated by the HOMA-IR indirect test. On specific days, two 20-week-old rats will be separated and randomly distributed in TG and SG. These animals will be followed until the eighth postoperative week. Subsequently, they will be euthanized, and the retroperitoneal and periepididymal fat deposits will be collected and weighed using a precision scale. In addition, the pancreas, liver and intestinal segments will be sent for pathological and immunohistochemical studies.&#xd;&#xa
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