998 resultados para Sheet-web


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Crematogaster cf. victima is a common inhabitant in the sheet web nests of the social spider Anelosimus eximius in the central Amazon basin near Manaus. A number of other ant species were found foraging on the non-sticky webs of A. eximius, but none of these reached the web occupation frequency found in C. cf. victima, nor, with the exception of an unidentified species of Pheidole, did they form satellite nests in the web, as did this species. Many prey which escaped the knock-down threads of the sheet web of A. eximius colonies were captured by ants in the lower web portions which they dominated. Furthermore, prey which were rejected by A. eximius, especially large, heavily sclerotized beetles, were also consumed by this ant. Repeated observations and experiments suggest that C. cf. victima is able to deter A. eximius activity through aerial venom release. Resources lost by A. eximius colonies to ants, especially C. cf. victima, in colonial web area and prey, may pose significant costs and may reduce colony growth.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Web Science(2) Participant Information Sheet

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Web Science_Participant Information Sheet

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In this study, the stability of anchored cantilever sheet pile wall in sandy soils is investigated using reliability analysis. Targeted stability is formulated as an optimization problem in the framework of an inverse first order reliability method. A sensitivity analysis is conducted to investigate the effect of parameters influencing the stability of sheet pile wall. Backfill soil properties, soil - steel pile interface friction angle, depth of the water table from the top of the sheet pile wall, total depth of embedment below the dredge line, yield strength of steel, section modulus of steel sheet pile, and anchor pull are all treated as random variables. The sheet pile wall system is modeled as a series of failure mode combination. Penetration depth, anchor pull, and section modulus are calculated for various target component and system reliability indices based on three limit states. These are: rotational failure about the position of the anchor rod, expressed in terms of moment ratio; sliding failure mode, expressed in terms of force ratio; and flexural failure of the steel sheet pile wall, expressed in terms of the section modulus ratio. An attempt is made to propose reliability based design charts considering the failure criteria as well as the variability in the parameters. The results of the study are compared with studies in the literature.

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Nos últimos anos, o processo de ensino e aprendizagem tem sofrido significativas alterações graças ao aparecimento da Internet. Novas ferramentas para apoio ao ensino têm surgido, nas quais se destacam os laboratórios remotos. Atualmente, muitas instituições de ensino disponibilizam laboratórios remotos nos seus cursos, que permitem, a professores e alunos, a realização de experiências reais através da Internet. Estes são implementados por diferentes arquiteturas e infraestruturas, suportados por vários módulos de laboratório acessíveis remotamente (e.g. instrumentos de medição). No entanto, a sua inclusão no ensino é ainda deficitária, devido: i) à falta de meios e competências técnicas das instituições de ensino para os desenvolverem, ii) à dificuldade na partilha dos módulos de laboratório por diferentes infraestruturas e, iii) à reduzida capacidade de os reconfigurar com esses módulos. Para ultrapassar estas limitações, foi idealizado e desenvolvido no âmbito de um trabalho de doutoramento [1] um protótipo, cuja arquitetura é baseada na norma IEEE 1451.0 e na tecnologia de FPGAs. Para além de garantir o desenvolvimento e o acesso de forma normalizada a um laboratório remoto, este protótipo promove ainda a partilha de módulos de laboratório por diferentes infraestruturas. Nesse trabalho explorou-se a capacidade de reconfiguração de FPGAs para embutir na infraestrutura do laboratório vários módulos, todos descritos em ficheiros, utilizando linguagens de descrição de hardware estruturados de acordo com a norma IEEE 1451.0. A definição desses módulos obriga à criação de estruturas de dados binárias (Transducer Electronic Data Sheets, TEDSs), bem como de outros ficheiros que possibilitam a sua interligação com a infraestrutura do laboratório. No entanto, a criação destes ficheiros é bastante complexa, uma vez que exige a realização de vários cálculos e conversões. Tendo em consideração essa mesma complexidade, esta dissertação descreve o desenvolvimento de uma aplicação Web para leitura e escrita dos TEDSs. Para além de um estudo sobre os laboratórios remotos, é efetuada uma descrição da norma IEEE 1451.0, com particular atenção para a sua arquitetura e para a estrutura dos diferentes TEDSs. Com o objetivo de enquadrar a aplicação desenvolvida, efetua-se ainda uma breve apresentação de um protótipo de um laboratório remoto reconfigurável, cuja reconfiguração é apoiada por esta aplicação. Por fim, é descrita a verificação da aplicação Web, de forma a tirar conclusões sobre o seu contributo para a simplificação dessa reconfiguração.

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El proyecto de creación de una Aplicación web sobre los diferentes perfiles de mercado de las provincias canadienses, consiste en la recopilación de información de diversas fuentes académicas, con el fin de crear una guía electrónica que permita a los exportadores colombianos tener información precisa y actualizada sobre cada una de las provincias canadienses.

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A knowledge based optimism technique has been developed to predict solutions for quality issues found in an initial draw die design. Post processing of the initial design yields all the features applying forces, and major quality issues. Using the geometric relationship between the two, a knowledge-base is interrogated to determine the possible corrective actions. These actions are then passed through a fast semi-analytical model to determine the level of change required. Results from a 2D forming are presented to highlight the advantage of the new algorithms over current optimisation techniques.

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To reduce weight and improve passenger safety there is an increased need in the automotive industry to use Ultra High Strength Steel (UHSS) for structural and crash components. However, the application of UHSS is restricted by their limited formability and the difficulty of forming them in conventional stamping. An alternative method of manufacturing structural auto body parts from UHSS is the flexible roll forming process, which allows the manufacture of metal sheet with high strength and limited ductility into complex and weight-optimized components. One major problem in the flexible roll forming of UHSS is the web-warping defect, which is the deviation in height of the web area over the length of the profile. It has been shown that web-warping is strongly dependant to the permanent longitudinal strain formed in the flange of the part. Flexible roll forming is a continuous process with many roll stands, which makes numerical analysis extremely time intensive and computationally expensive. An analytical model of web-warping is therefore critical to improve design efficiency during the early process design stage before FEA is applied. This paper establishes for the first time an analytical model for the prediction of web-warping for the flexible roll forming of a section with variable width. The model is based on evaluating longitudinal edge strain in the flange of the part. This information is then used in combination with a simple geometrical model to investigate the relationship between web-warping and longitudinal strain with respect to process parameters.

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Pós-graduação em Engenharia Elétrica - FEIS

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This paper describes the procedures used to create a distributed collection of topographic maps of the Austro-Hungarian Empire, the Spezialkarte der Öesterriechisch-ungarnischen Monarchie, Masse. 1:75,000 der natur. This set of maps was published in Vienna over a period of years from 1877 to 1914. The part of the set used in this project includes 776 sheets; all sheets from all editions number over 3,665. The paper contains detailed information on how the maps were converted to digital images, how metadata were prepared, and how Web-browser access was created using ArcIMS Metadata Server. The project, funded by a 2004 National Leadership Grant from the Institute for Museums and Library Science (IMLS), was a joint project of the Homer Babbidge Library Map and Geographic Information Center at the University of Connecticut, the New York Public Library, and the American Geographical Society’s Map Library at the University of Wisconsin Milwaukee.

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Macroalgae, in particular kelps, produce a large amount of biomass in Kongsfjorden, which is to a great extent released into the water in an annual cycle. As an example, the brown alga Alaria esculenta loses its blade gradually, 3 ± 0.8 % of the blade area per day (August 2012), thereby adding to the pool of particulate organic matter (POM) in the fjord. Upon release small thallus pieces are "aging" in that they are prone to leaching and serving as substrate for microorganisms, thus turning into palatable food for suspension and bottom feeders. In order to define a macroalgal baseline for the Kongsfjorden food web, stable isotopes d14C and d15N were measured in individuals of A. esculenta, Saccharina latissima and Laminaria digitata directly sampled after collection and in artificially produced POM (aPOM) of A. esculenta that was allowed to age under experimental conditions. In aPOM from this species sampled in August 2012 the C/N ratios decreased between d1 and d8 of a 14-day culture period in parallel to the fading photosynthetic activity of the algal fragments as demonstrated by use of an Imaging-PAM. Microscopic observations of the aPOM in August 2012 and 2013 revealed the frequent occurrence of small brown algal endo- and epiphytes. First feeding experiments with Mysis oculata (Mysids) and Hiatella arctica (Bivalves) showed that these species can ingest macroalgal POM. The importance of kelp-derived POM for the food web is subject of the current research.

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The collective impact of humans on biodiversity rivals mass extinction events defining Earth's history, but does our large population also present opportunities to document and contend with this crisis? We provide the first quantitative review of biodiversity-related citizen science to determine whether data collected by these projects can be, and are currently being, effectively used in biodiversity research. We find strong evidence of the potential of citizen science: within projects we sampled (n = 388), ~1.3 million volunteers participate, contributing up to US Dollar 2.5 billion in-kind annually. These projects exceed most federally-funded studies in spatial and temporal extent, and collectively they sample a breadth of taxonomic diversity. However, only 12% of the 388 projects surveyed obviously provide data to peer-reviewed scientific articles, despite the fact that a third of these projects have verifiable, standardized data that are accessible online. Factors influencing publication included project spatial scale and longevity and having publically available data, as well as one measure of scientific rigor (taxonomic identification training). Because of the low rate at which citizen science data reach publication, the large and growing citizen science movement is likely only realizing a small portion of its potential impact on the scientific research community. Strengthening connections between professional and non-professional participants in the scientific process will enable this large data resource to be better harnessed to understand and address global change impacts on biodiversity.

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This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet II [of 10] covering a portion of the Yellow River (Huang He) region in eastern Qinghai Sheng and southern Gansu Sheng, China. The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.

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This layer is part of a set of georeferenced, raster images of the manuscript, paper map set entitled: Ch'ing-Hai upper Yellow River expedition : Rock and Simpson, 1925-27, [cartography by J.F. Rock]. Scale 1:250,000. This layer image is of Sheet III [of 10] covering a portion of the Yellow River (Huang He) region in eastern Qinghai Sheng and southern Gansu Sheng, China. The map set details the route and surrounding environs of the Arnold Arboretum's "Western China" expedition led by Joseph Rock, 1924-1927. The set covers a portion of the Yellow River (Huang He) region in south central China (Qinghai, Gansu, and Sichuan shengs (a portion of historic Tibet)). It shows features, labeled variously in English, Chinese, Wade-Giles transliteration, and Tibetan, including: rivers, streams, lakes, mountains, gorges, valleys, plateaus, plains, cities, towns, villages, provincial capitals, county seats, passes, monasteries, ruin sites, native tribe locations, and more. Relief is shown by hachures, spot heights, and landform drawings. The original manuscript map set is part of the Harvard College Library, Harvard Map Collection. "Joseph Rock traced his travels for the [Arnold] Arboretum's [Western China] 1924-1927 expedition in a colorful, hand-drawn map entitled 'Ch'ing-Hai upper Yellow River expedition.' The pen-and-ink drawing was made on ten sheets that when joined form a single, irregularly-shaped map, approximately six by eight feet in size. The individual sheets are numbered, using roman numerals; on sheet VII is a second title, 'Choni Territory, Upper and Lower T'ieh-Pu country and route to Sung-Pan, J. F. Rock, 1925-1927.' Topographical and other features are identified using a combination of English, Chinese characters, Wade-Giles transliterations and Tibetan script. Rock's attractive cursive style and use of hachures, spot heights, and landform drawings to depict relief add character to the map." -- Text from the Arnold Arboretum Web site.