6,465 research outputs found
Análise de torres de transmissão submetidas a cargas dinâmicas
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Civil.Torres de transmissão de energia são de grande importância para o abastecimento elétrico de um país, pois são elas que suportam os cabos que transmitem a energia. A ruptura ou mesmo a danificação destas estruturas pode ter conseqüências significativas para a economia local. No Brasil o principal carregamento que incide sobre uma linha de transmissão de energia é causado pela ação do vento. A norma brasileira NBR 6123 tem um mapa de isopletas do vento, com a indicação da velocidade média para um período de recorrência de 50 anos a uma altura de 10 metros do solo. Como usualmente o período fundamental da estrutura de torres de transmissão é inferior a 1 s, a maioria das normas permite que seu dimensionamento seja realizado para cargas estáticas equivalentes, obtidas a partir da velocidade média do vento e alguns parâmetros adicionais, função da localização geográfica da torre, sua altura e a área efetiva de incidência do vento. No entanto não são raros os eventos de colapso de torres de transmissão de energia no Brasil, e além disso, a ocorrência de fortes rajadas e ciclones vêm aumentando no país nos últimos anos. Justificase assim a necessidade de uma verificação mais apurada do projeto de torres de transmissão, neste caso sob a ação dinâmica do vento. Escolheu-se para este trabalho uma torre de transmissão típica, situada no sul do Brasil. A estrutura da torre é modelada por elementos de pórtico 3D, sendo consideradas rígidas as ligações das barras principais e rotuladas as ligações de barras secundárias. As análises dinâmicas da ação do vento são realizadas no domínio do tempo, sendo a componente turbulenta do vento obtida a partir dos espectros de Davenport e Kaimal e série de Fourier. Outro caso de carregamento considerado neste tipo de torre é a carga que simula a ruptura de um ou mais cabos de energia, que são fixados à torre para manter suas catenárias com as alturas de segurança nos vãos adjacentes. A ruptura de um cabo em um dos lados da torre pode ser simulada aplicando-se uma força no suporte, no lado contrário. Esta força pode ser aplicada estática ou dinamicamente e pode ser decomposta em duas parcelas: uma devida ao peso do cabo e a outra a tração no cabo, utilizada para o seu correto posicionamento na linha de transmissão. Admite-se nas análises que a torre tem comportamento elástico-linear, e utiliza-se o método da superposição modal para resolver as equações de movimento da estrutura. Conclusões e recomendações são apresentadas no final do trabalho
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No full textHere is a curious book. Its title-page declares "The Artist's Book of Fables" but its pre-title-page has "Fables, Original and Selected, with a Memoir of the Author." After that title-page, it is identical with "Fables, Original and Selected" as in our copy printed by John Murray in 1833. There is again an AI at the front and an index of engravings and engravers at the back. I found that copy twenty years ago. I had found an inferior copy twenty-two years before that. At that time, I noted Aesopic fables here including "Stone Broth" and "The Mouse and the Oyster."This is a hardbound book (hard cover)James Northcote, R.A
Marriage record of Suarez, Fructuoso and Torres, Belen Estevez
No full textMarriage license for Fructuoso Suarez and Belen Estevez Torres. R.A. Lord was the Notary Public
Turbulent entrainment in a shearless mixing layer at the edge of a cloud
No full textThree-dimensional direct numerical simulations which combine the Eulerian description of temperature, vapor content and velocity with a Lagrangian ensemble of cloud water droplets are used to study the turbulent entrainment and subsequent mixing of clear air with a cloudy air filament. The study is conducted in a shearless mixing layer setup which is adjusted to realistic conditions at a cumulus cloud boundary. The magnitude of turbulent velocity fluctuations in- and outside the cloud can be varied independently. We find that the evolution of the cloud water droplet ensemble depends slightly only on the contrast of turbulent velocity fluctuations in- and outside the cloud filament. The buoyancy feedback on the flow via the evaporating droplets causes a transient amplification of all fluctuations before the turbulence eventually decays. We study the evolution of the probability density functions of droplet size as well as of supersaturation, temperature and vorticity at the droplet positions
Flyleaf of The Village Politicians, signed by author and publisher R.A. Parsons, and printed by Guardian Ltd.
No full textNewIntroduction. Flyleaf of the The Village Politicans by R.A. Parsons and printed by Guardian Ltd.DA vol. 15 no.
Non-Linear Time Series Analysis of Deep Groundwater Levels: An application to the Veluwe
No full textThe objective of this study is to improve the simulation of deep groundwater levels by time se- ries models with pre-defined impulse response functions. This is attempted by adding a conceptual non-linear root zone model to simulate the recharge series to the model and by testing the use of a separate response function for the percolation zone. Three root zone models are developed based on two different recharge mechanisms: preferential flow, percolation, and a combination of the two. The performance of these models is compared to a linear model that is commonly used in time se- ries models to simulate the recharge. The approach is applied to groundwater level measurements in the Veluwe, a largely forested area in the Netherlands characterized by thick unsaturated zones. The effect of groundwater extractions and land reclamations is added to the model to further im- prove the simulation of the groundwater levels. The models are tested on three observations wells with increasing thickness of the unsaturated zone, varying from 7 m to 29 m to 49 m. The results show that model performance is improved by the implementation of a non-linear root zone model, particularly in simulating the peaks and lows in the groundwater levels. The recharge fluxes simulated by the non-linear models show different patterns that are physically more realistic than those simulated by the linear model. It is shown that different recharge series result in simulated groundwater levels that are very similar. This is a clear example of equifinality and it is recommended to introduce new sources of information to validate the modelled processes (e.g., water content measurements of the percolation zone or actual evaporation data). For the shallow well, the models with a single response function are selected as the best. The largest improvements for the deeper groundwater levels are obtained by the addition of a separate response for the percolation zone. For example, the average deviation from the observed ground- water levels decreased 0.18 m to 0.08 m for the deepest observation well by applying the separate response function. The models with an additional response function were better at simulating the estimated time to peak, the time it takes a recharge pulse to cause a peak in the groundwater levels. The time to peak is introduced in this research as a qualitative indicator to validate the modelled processes. The simulated responses indicate that the groundwater levels respond very quickly to water that leaves the root zone, even though the percolation zone is tens of metres thick. For each of the observations wells it is investigated if adding the effect of groundwater extrac- tions or land reclamations of Flevoland to the models improves the simulation of the groundwater levels. For the shallow well it is concluded that either the effect of land reclamations or groundwater extractions needs to be taken into account. Since these two stresses are correlated, it is concluded that only one of these should be taken into account when no further information is available to con- strain the models. For the medium deep well, the additional stresses did not significantly improve model performance and it is concluded that they do not have to be taken into account for this well. For the deep well, model performance is improved by both stresses. The largest improvements are observed when the effect of groundwater extractions is considered in the model. For implemen- tation of these stresses, the entire simulation period should be used for calibration, or constraints have to be implemented to obtain realistic results.Water ResourcesWater ManagementCivil Engineering and Geoscience
POTENTIAL IMPACTS OF THE ASIAN CLIMBING PERCH ON QUEENSLAND
No full textRisk of establishment of the freshwater climbing perch (Anabas testudineus) in mainland Queensland from the Torres Strait is high. The species is dispersed through human assistance and/or attributes that assist its own spread. The species has the potential to out-compete native freshwater and estuarine species, and has sharp well-developed gill plates and spines that may choke and kill predatory species like barramundi if swallowed. The presence of climbing perch would severely impact Queensland’s inshore and freshwater fisheries, both commercial and recreational. The net present value of expected lost fishing activity due to build-up of the climbing perch is $48.5 million when the probability of introduction is 20 per cent. Analysis of potential spending on an entry prevention strategy for the climbing perch can be justified, with a benefit cost ratio of 150 to 1.Invasive species, impact, risk, Resource /Energy Economics and Policy, Risk and Uncertainty,
Chemicals from renewable biomass: A renaissance in carbohydrate chemistry
No full textThe conversion of sugars, derived from waste polysaccharide biomass, to commodity chemicals by fermentation or catalytic hydrogenation, oxidation or dehydration or combinations thereof are reviewed.Accepted Author ManuscriptBT/Biocatalysi
KONSEP HARKAT DAN MARTABAT PEREMPUAN DALAM BUKU HABIS GELAP TERBITLAH TERANG KARYA R.A KARTINI DAN RELEVANSINYA TERHADAP PENDIDIKAN ISLAM
No full textThe background of this research originated from the admiration of the author of the book Habis Gelap Terbitlah Terang by R.A. Kartini who has an extraordinary spirit in fighting for the dignity of women. Women who are not valued, are not recognized, and do no have the opportunity to develop themselves during the R.A. Kartini, now has freedom. His dignity and recognition are recognized by the community. But along with the development of the era that was so extraordinary. Book Habis Gelap Terbitlah Terang began to be forgotten by the people. This research included qualitative research and the type of research that the authors do is library research. The research approach used is the historical approach. The method of data collection in this study is adjusted to the type of research conducted, namely the research library, then the right data collection method is the collection and documentation method. Data analysis in this study uses content analysis method. Based on the results of research conducted by the author about the concept of the dignity of women in view of R.A. Kartini can be concluded that the concept of the dignity of women in the view of R.A. Kartini has seven concepts: educated women, virtuous women, skilled women, free women who are civilized and educated, men collaborate with women, women who are knowledgeable about religion, and delete the caste system in society. The seven concepts have a close relationship to Islamic education which is focused on the goal of Islamic education, namely facilitates women to develop themselves, both in the realm of individuals, families, social and in work so that we create human being.Latar belakang penelitian ini berawal dari kekaguman penulis pada buku Habis Gelap Terbitlah Terang karya R.A. Kartini yang memiliki semangat luar biasa dalam memperjuangkan harkat dan martabat perempuan. Perempuan yang tidak dihargai, tidak diakui, dan tidak memiliki kesempatan untuk mengembangkan diri pada masa R.A. Kartini, kini telah memiliki kebebasan. Harkat dan martabatnya terakui oleh masyarakat. Namun seiring perkembangan zaman yang begitu luar biasa. Buku Habis Gelap Terbitlah Terang ini mulai terlupakan oleh masyarakat. Penelitian ini termasuk penelitian kualitatif dan jenis penelitian yang penulis lakukan merupakan penelitian kepustakaan (library research). Pendekatan penelitian yang digunakan yaitu pendekatan sejarah (histori). Metode pengumpulan data dalam penelitian ini disesuaikan dengen jenis penelitian yang dilakukan, yaitu library research maka metode pengumpulan data yang tepat adalah metode pengumpulan dan dokumentasi. Analisis data pada penelitian ini menggunakan metode content analysis. Berdasarkan hasil penelitian yang dilakukan oleh penulis tentang konsep harkat dan martabat perempuan dalam pandangan R.A. Kartini dapat disimpulkan bahwa konsep harkat dan martabat perempuan dalam pandangan R.A. Kartini ada tujuh konsep yaitu: perempuan berpendidikan, perempuan berbudi luhur, perempuan berketerampilan, perempuan bebas yang beradab dan terpelajar, laki-laki bekerjasama dengan perempuan, perempuan yang berpengetahuan ilmu agama, serta menghapus sistem kasta di masyarakat. Ketujuh konsep tersebut memiliki hubungan yang erat terhadap pendidikan Islam yang difokuskan pada tujuan pendidikan Islam yaitu memfasilitasi perempuan untuk mengembangkan diri, baik dalam ranah individu, keluarga, sosial dan dalam berkarya sehingga terciptalah insan kamil
Asymmetric Growth and Inflation Developments in the Acceding Countries: A New Assessment. NBB Working Paper Nr. 63, November 2004
No full textIn this paper, we use a SVAR model in order to study the asymmetry of growth and inflation developments in the acceding countries vis-à-vis the euro area over the years 1995-2003. The model combines two strands of the literature, the explanation in terms of country-specific and euro area shocks, and a further split between supply and demand shocks. The four structural shocks may all create asymmetries vis-à-vis the euro area. It appears that country-specific shocks are the main source of growth or inflation divergence, rather than the distinct way in which acceding countries react to euro area shocks. But whereas country-specific supply shocks are mainly responsible for growth divergence, country-specific demand shocks are mainly responsible for inflation asymmetry. Hence, a low asymmetry in terms of growth does not necessarily imply a low asymmetry in terms of inflation, although the latter is particularly important for countries aiming to join the euro area. There is some evidence that both asymmetries were on the fall over the last years of the sample
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