Características hidráulicas de tubos de bambu gigante

Neto, José Adolfo de Almeida; Testezlaf, Roberto; Matsura, Edson Eiji

doi:10.1590/s1415-43662000000100001

Cited by 4 publications

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“…O Dendrocalamus giganteus Munro é uma espécie de rápido crescimento e versátil (Almeida et al, 2000). Aspectos como espessura da parede, diâmetro e linearidade longitudinal do colmo, comprimento das hastes, aliada à produtividade florestal, fazem dela uma espécie apropriada para reflorestamentos e utilizações industriais (Ostapiv, 2011), inclusive para confecção de laminado colado (Beraldo & Rivero, 2003).…”

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Caracterização Anatômica e Física do Bambu Gigante (Dendrocalamus giganteus Munro)

et al. 2015

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The work aimed to carry out the anatomical and physical characterizations of adult bamboo rods of Dendrocalamus giganteus Munro. So, four rods were collected and sectioned in culms of 2.10 m long. From the ends of the culms were obtained 5.0 cm thick disks that were transformed into samples for anatomical and physical characterizations. In this study, were measured the percentage of fibers, vessels, parenchyma, the moisture content, the basic specific gravity and oven dry specific gravity and shrinkage. The studied bamboo has 0 to 4 vessels mm -2 , with average of 2 vessels mm -2 , with average fiber length of 2.72 mm and 50.72% consists of parenchyma tissue. The moisture content was quantified at 60%, the basic specific gravity in 0.66 g cm -3 , the oven dry specific gravity in 0.83 g cm -3 and volumetric shrinkage in 15.40%. It was observed that the bamboo physical characteristics were influenced by the layout and anatomical elements proportion.

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Section: Introductionunclassified

Caracterização Anatômica e Física do Bambu Gigante (Dendrocalamus giganteus Munro)

et al. 2015

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Agricultural drainage pipe in Guadua angustifolia: implications of Manning roughness in Pitalito forest stands

Duarte-Toro,

Silva-Chavarro,

Gil-Hernandez

2024

Int. J. Environ. Sci. Technol.

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Water extraction in agricultural fields with high saturation levels requires drainage systems that increase land preparation costs, so looking for new options for materials that function as drainage pipes that provide a better technical–economic relationship is crucial. In this study, Manning roughness values were analyzed in the culms of Guadua angustifolia considering three factors: flow, section, and location site of the forest stands. This study was carried out in the rural area of the municipality of Pitalito; the characterization of culms was made based on the Colombian technical standards (NTC) 5726 and 5727, the cutting and elaboration of test pieces according to the NTC 5525, and finally, the hydraulic tests were carried out. The roughness values oscillated between 0.1089 and 0.0337 according to the different flow evaluated values in the laboratory tests, between 0.1004 and 0.0356 for the sections analyzed, and between 0.0909 and 0.0533 according to the sample extraction area. The multifactor ANOVA established a significant relationship for the flow and section on the Manning n roughness, while the zone was insignificant.

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Coeficiente de rugosidade de Manning para o rio Paracatu

Lyra¹,

Cecílio

Zanetti

et al. 2010

Rev. bras. eng. agríc. ambient.

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RESUMOPela teoria do escoamento em canais abertos, o coeficiente de rugosidade de Manning é um dos principais parâmetros para descrição da vazão sobre uma superfície. Uma das dificuldades da aplicação da equação de Manning é a definição do seu coeficiente de rugosidade em rios e canais, razão pela qual o presente estudo tem como objetivo, estimar o coeficiente de rugosidade de Manning para os períodos de vazão mínima e máxima média mensal, em alguns trechos do rio Paracatu, e propor um modelo baseado em redes neurais artificiais para estimar o coeficiente de rugosidade. O coeficiente foi determinado em função das características geométricas do canal (área molhada, raio hidráulico e declividade do canal) e das séries de vazão de seis postos fluviométricos do rio Paracatu. Utilizaram-se séries de vazão de 21 anos . O coeficiente de rugosidade não apresenta tendência (maior ou menor) em função apenas do período seco ou de cheia. As características da margem e do leito do rio influenciam diretamente nos valores de coeficiente de rugosidade. O modelo baseado em rede neural apresentou desempenho satisfatório, o que possibilita estimar o coeficiente de rugosidade em função da cota, vazão, declividade e do raio hidráulico do rio. Palavras-chave: vazão, condutos livres, redes neurais artificiaisManning roughness coefficient for Paracatu river, Brazil ABSTRACTAccording to open channel draining theory, the Manning's roughness coefficient is one of most important parameters to describe surface flow. One of the difficulties in applications of Manning's equation is the definition of its roughness coefficient in rivers and channels. Thus, the aims of this paper are to estimate the Manning's roughness coefficient for the periods of minimum and maximum mean monthly flow in some parts of Paracatu river and to propose a model based on artificial neural networks to estimate the roughness coefficient. The coefficient was determined in function of channel geometrical characteristics (wetted area, hydraulic radius and slope of the channel) and of the outflow series of six fluviometric stations of Paracatu river. Long-term series of 21 years (1976 -1996) of outflow were used. The roughness coefficient does not show any tendency (up or down)as a function of the dry or overflow periods only. The characteristics of margin and watercourse of river influenced directly the roughness coefficient data. The model based on neural network showed satisfactory performance, which allow us to estimate the roughness coefficient as a function of the quota, slope and hydraulic radius of the river.

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Características hidráulicas de tubos de bambu gigante

Cited by 4 publications

References 0 publications

Caracterização Anatômica e Física do Bambu Gigante (Dendrocalamus giganteus Munro)

Caracterização Anatômica e Física do Bambu Gigante (Dendrocalamus giganteus Munro)

Agricultural drainage pipe in Guadua angustifolia: implications of Manning roughness in Pitalito forest stands

Coeficiente de rugosidade de Manning para o rio Paracatu

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