151 research outputs found
Heavy Load Rollers in Logistic Systems
Wheels with polyurethane bandages are in common use in logistic systems with friction gear actuation. Many research projects have studied the mechanical construction of these heavy load wheels. The studies have been theoretical as well as experimental. Research interests at the department of machine elements include the wear in the presence of intermediate material on the contact area between the bandage surface and the contact surface on which the wheel rolls off. This problem, which is observed when examining this tribochemical system, has not been studied before. Within this project both one-phase intermediate materials such as sand, water, cutting-cooling-emulsion, metal splinters and two-phase intermediate materials such as sand/water and combinations of the latter were taken into consideration. In addition, the exposure of the bandage hardness, the cross linking agent of the polyurethane, the mechanical stress, and the slip are observed. The analysis of the experimental results indicates that friction gear actuators can be constructed abrasion-optimised, taking into account special interfering effects in the form of intermediate materials in the contact area
How can hydrological modeling help to understand process dynamics in sparsely gauged tropical regions - case study Mata Âtlantica, Brazil.
Monitoramento hidrometeorológico em bacias rurais do Bioma Mata Atlântica.
Visando estabelecer estudos sobre a hidrologia de bacias com uso agrícola nas regiões tropicais, foram instaladas redes de instrumentação hidrometeorológica em duas bacias rurais. Caracterizadas por um mosaico de classes de cobertura e uso da terra, na Mata Atlântica Fluminense, as bacias são: a do córrego Pito Aceso, no Município de Bom Jardim, região Serrana Fluminense, e a bacia dos Rios Guapiaçu-Macacu, cuja drenagem tem sua foz na Baía de Guanabara. Os resultados obtidos no monitoramento provêm informações essenciais para parametrizar modelos simuladores de processos de fluxo de água e transporte de nutrientes e sedimentos. No projeto AgroHidro, a associação do monitoramento ao uso de modelos visa prover maior conhecimento dos processos de hidrologia em bacias, bem como de suas interações com os sistemas agrícolas
Flow intermittence prediction using a hybrid hydrological modelling approach: influence of observed intermittence data on the training of a random forest model
Rivers are rich in biodiversity and act as ecological corridors for plant and animal species. With climate change and increasing anthropogenic water demand, more frequent and prolonged periods of drying in river systems are expected, endangering biodiversity and river ecosystems. However, understanding and predicting the hydrological mechanisms that control periodic drying and rewetting in rivers is challenging due to a lack of studies and hydrological observations, particularly in non-perennial rivers. Within the framework of the Horizon 2020 DRYvER (Drying River Networks and Climate Change) project, a hydrological modelling study of flow intermittence in rivers is being carried out in three European catchments (Spain, Finland, France) characterised by different climate, geology, and anthropogenic use. The objective of this study is to represent the spatio-temporal dynamics of flow intermittence at the reach level in mesoscale river networks (between 120 and 350 km2). The daily and spatially distributed flow condition (flowing or dry) is predicted using the J2000 distributed hydrological model coupled with a random forest classification model. Observed flow condition data from different sources (water level measurements, photo traps, citizen science applications) are used to build the predictive model. This study aims to evaluate the impact of the observed flow condition dataset (sample size, spatial and temporal representativity) on the performance of the predictive model. Results show that the hybrid modelling approach developed in this study allows the spatio-temporal patterns of drying to be accurately predicted in the three catchments, with a sensitivity criterion above 0.9 for the prediction of dry events in the Finnish and French case studies and 0.65 in the Spanish case study. This study shows the value of combining different data sources of observed flow condition to reduce the uncertainty in predicting flow intermittence.</p
Bolzano’s Argument for the Existence of Substances: a Formalization with Two Types of Predication
Modelagem de processos hidrológicos em bacias de mesoescala escassamente monitoradas na Mata Atlântica, RJ, Brasil.
A Bacia Hidrográfica do Guapi-Macacu (BHGM), situada na região metropolitana do Rio de Janeiro, é responsável pelo abastecimento de mais de dois milhões de pessoas. A região é sujeita a inundações e deslizamentos no período chuvoso, e escassez hídrica na estação seca, com riscos para o abastecimento doméstico e agrícola nos anos de menor precipitação. Ferramentas de modelagem podem colaborar para a gestão integrado de recursos hídricos e apoiar a tomada de decisão. Este estudo utilizou o modelo hidrológico J2K, desenvolvido na plataforma Jena Adaptable Modeling System (JAMS), para representar o comportamento hidrológico da BHGM. Os procedimentos de parametrização e calibração do modelo foram baseados em dados de campo e de séries temporais meteorológicas e de vazão. O modelo parametrizado para a BHGM foi aplicado numa bacia adjacente, a Bacia Dois Rios (BHDR). Os indicadores de desempenho do modelo foram satisfatórios a bons para ambas as bacias e mostraram a viabilidade de aplicar conjuntos de parâmetros obtidos a partir de bacias instrumentadas em âmbito regional, i.e., em bacias semelhantes quanto às características geomorfológicas e climatológicas
Etapas metodológicas para a modelagem do nitrogênio na água na bacia Guapi-Macacu, Rio de Janeiro, RJ.
A qualidade da água depende de muitos fatores naturais e antrópicos. Estes impactos precisam ser caracterizados e quantificados para subsidiar cenários futuros e a gestão de recursos hídricos no âmbito das bacias hidrográficas. A Bacia Guapi-Macacu, pertencente ao Bioma Mata Atlântica, é a terceira no ranking de abastecimento de água no Estado do Rio de Janeiro. O propósito deste trabalho foi apresentar as etapas metodológicas para a modelagem hidrológica das formas de nitrogênio nesta bacia. Nesse caso, o modelo hidroquímico J2000-S foi aplicado. A fim de calibrar e validar o modelo, foi instalada uma rede de monitoramento hidrometeorológica e de qualidade da água. Dados secundários também foram organizados e utilizados. Etapas do trabalho: coleta e análise de dados, delimitação das unidades de resposta hidrológica; calibração e validação temporal do modelo hidroquímico; validação espacial e análise de incertezas. A principal fonte de nitrogênio é o esgoto doméstico, seguida das fontes difusas relacionadas à agricultura. Concluiu-se que a disponibilidade de dados é um grande desafio, mas a implantação de redes de monitoramento sólidas pode fornecer os dados necessários para a modelagem
The Prenective View of Propositional Content
Beliefs have what I will call ‘propositional content’. A belief is always a belief that so-and-so: a belief that grass is green, or a belief that snow is white, or whatever. Other things have propositional content too, such as sentences, judgments and assertions. The Standard View amongst philosophers is that what it is to have a propositional content is to stand in an appropriate relation to a proposition. Moreover, on this view, propositions are objects, i.e. the kind of thing you can refer to with singular terms. For example, on the Standard View, we should parse the sentence ‘Simon believes that Sharon is funny’ as: [Simon] believes [that Sharon is funny]; ‘Simon’ is a term referring to a thinking subject, ‘that Sharon is funny’ is a term referring to a proposition, and ‘x believes y’ is a dyadic predicate expressing the believing relation. In this paper, I argue against the Standard View. This is how I think we should parse ‘Simon believes that Sharon is funny’: [Simon] believes that [Sharon is funny]; here we have a singular term, ‘Simon’, a sentence ‘Sharon is funny’, and a ‘prenective’ joining them together, ‘x believes that p’. On this Prenective View, we do not get at the propositional content of someone’s belief by referring to a reified proposition with a singular term; we simply use the sentence ‘Sharon is funny’ to express that content for ourselves. I argue for the Prenective View in large part by showing that an initially attractive version of the Standard View is actually vulnerable to the same objection that Wittgenstein used against Russell’s multiple-relation theory of judgment
Priority monism and part/whole dependence
Priority monism is the view that the cosmos is the only independent concrete object. The paper argues that, pace its proponents, Priority monism is in conflict with the dependence of any whole on any of its parts: if the cosmos does not depend on its parts, neither does any smaller composit
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