1000 resultados para Drainage system


Relevância:

60.00% 60.00%

Publicador:

Resumo:

The environmental issue has been considered of fundamental importance for the well being of the present and future generations and is inserted into the commitment of political parties at federal, state and municipal government programs, into the interests of popular organizations and business planning. The Parque Ecológico Cidade da Criança is one of the most sought after places for visitation at Presidente Prudente – SP. Located outside the Raposo Tavares Highway, next to the exhibition grounds and beside the agricultural school, has more than 30 acres of area with an infrastructure designed for recreation and leisure activities for all ages and has received new investment of the public power. Given the importance of the ecological aspects, the objective of this work is to perform an environmental diagnosis in order to be able to submit proposals for solving the problems encountered and improve the use of the environmental resources. Therefore, the study was divided into three foci: sewage disposal, erosion process and control of the stormwater drainage system. It was checked the discharge of sewage from the restaurant on exposed soil, erosion processes that develop at the camel and llama cages ground and erosion processes resulting from the convergence of the stormwater in the highest region of the park. Based on these studies, proposals of solution were made for each case, having considered the effectiveness of the project

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Due to an intense process of population growth and urban density in Americana (SP), mainly due to the development of the local textile industry after 1970, there was, concomitant to the occupation of the margin of rivers and streams, soil sealing that increased the level of superficial runoff, triggering frequent floods. Based on the analysis of these processes we investigate the conditions of one densely urbanized area of the county, the Córrego do Parque, in three time series, 1977, 1996 and 2008. Taking as the starting the characterization and spatial distribution of landscape physiography, we prepared thematic letters and synthetic maps digital scale 1:10,000 from photointerpretation of aeroframes. The thematic maps were produced by scanning with subsequent edition using the software Auto-Cad Map. Checking the data and of geographic coordinates with GPS (Global Positioning System). Regarding land use classes, we used the description of the Soil Conservation Service (1975) which allowed us to get the Curve Number parameter, which will be used in hydrologic modeling for verification of flooding (Tucci, 1989). For the process of hydrologic modeling, we used models based on Methodology Object Oriented Modeling Applied to Water Resource Systems, Viegas Filho (1999), using the computer program called IPHS1, which uses models of the Soil Conservation Service (SCS , 2004), for conversion of rainfall-runoff and the spread of excessive rain. The results indicate that increased waterproofing generated by the change in use and occupation over the past decades promoted the increased surface runoff and drainage system overload, increasing the intensity of floods

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The management of urban areas must consider aspects related to urban drainage, especially in hot and humid environments, and such aspects must be incorporated on director plans. This is quite important in urban areas settled on natural fragile hydro-geomorphologic areas. So, the main aim of this paper was to present the urban drainage diagnostic made in Rio Claro (SP-Brazil), discussing its results and evaluating the applied techniques. Further, there were presented some proposed directions based on such analyses. From the obtained results it was possible to verify that the impacts caused by the inefficient urban drainage system incur on direct and indirect effects such as flood, erosion and water quality degradation.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

PURPOSE To ascertain whether the volume and circumference of the lacrimal sac and nasolacrimal duct as measured by contrast-enhanced computed tomographic dacryocystography (CT-DCG) before and after balloon dacryoplasty could be used to predict clinical success in children with congenital nasolacrimal obstruction. METHODS Nasolacrimal ducts of children aged 2 to 6 years with clinical signs of congenital nasolacrimal duct obstruction undergoing balloon dilation were imaged with contrast-enhanced CT-DCG before and 5 minutes after the procedure. The circumference of the most dilated portion of the lacrimal sac was measured on the axial plane. The volume of contrast within the nasolacrimal duct and sac was also measured before and after the procedure. Clinical success was defined as the disappearance of signs of epiphora. RESULTS A total of 18 nasolacrimal ducts of 13 children were included. The average circumference of the most dilated portion of the lacrimal sac was 1.30 +/- 0.45 cm (range, 0.64-2.50 cm) before the procedure. The average contrast volume was 0.12 +/- 0.08 cm(3) (range, 0.01-0.38 cm(3)) before and 0.07 +/- 0.06 cm(3) (range, 0.01-0.20 cm(3)) after (P = 0.01). Data were analyzed using multivariate logistic regression with a backward variable input model; a decrease in contrast volume before and after dilation (P = 0.04) was associated with clinical success, whereas the larger size of the most dilated portion of the lacrimal sac (P = 0.01) was associated with clinical failure. CONCLUSIONS Contrast-enhanced CT-DCG provides useful information about nasolacrimal anatomy in children with congenital nasolacrimal duct obstruction. The decrease in contrast volume before and after balloon dilation was predictive of success; A larger size of the most dilated portion of the lacrimal sac was associated with clinical failure. (J AAPOS 2012;16:464-467)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen 'complete' time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0-2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia, in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role for glacial climate cycles and refugia.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

OBJETIVO: Descrever uma série de pacientes portadores de obstrução do sistema lacrimal associado à radioiodoterapia para tratamento de carcinoma de tireoide, revisar os dados clínicos e a resposta ao tratamento cirúrgico desta rara complicação. MÉTODOS: Foi realizada uma análise retrospectiva dos achados oftalmológicos de pacientes com histórico de carcinoma de tireoide previamente submetidos à tireoidectomia e à RIT que foram encaminhados para cirurgia de vias lacrimais. RESULTADOS: Dezessete pacientes com carcinoma de tireoide tratados com tireoidectomia e RIT apresentaram obstrução do ducto nasolacrimal sintomática após período médio de 13,2 meses do tratamento do câncer. Onze pacientes tiveram epífora bilateral, 8 com mucocele de saco lacrimal. A idade dos pacientes variou entre 30 e 80 anos, sendo 10 com idade menor ou igual a 49 anos. A dose cumulativa média de radioiodo administrada foi de 571 mCi (variação entre 200-1200 mCi). Sintomas de obstrução nasal e aumento de glândulas salivares ocorreram em 53% dos pacientes. Todos os pacientes foram submetidos à dacriocistorrinostomia. Observou-se ainda que nos 3 pacientes mais jovens houve maior sangramento intraoperatótio e dilatação de saco lacrimal. A resolução completa da epífora e da dacriocistite ocorreu em 82,4%, e foi parcial em 17,6% (3 pacientes mantiveram queixa unilateral após a correção da obstrução bilateralmente). O seguimento médio foi de 6 meses (intervalo: 2-24 meses). CONCLUSÕES: Alta dose cumulativa de radioiodo, disfunção nasal e de glândulas salivares estão associadas à obstrução das vias lacrimais. Observa-se uma maior porcentagem de pacientes mais jovens apresentando quadro de dacriocistite quando comparado à dacrioestenose idiopática. A absorção de iodo radioativo pela mucosa do ducto nasolacrimal com subsequente inflamação, edema e fibrose parece ter relação direta com a obstrução do ducto nasolacrimal. O conhecimento desta complicação é importante para o estudo e abordagem correta desses pacientes.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Urbanization is a continuing phenomenon in all the world. Grasslands, forests, etc. are being continually changed to residential, commercial and industrial complexes, roads and streets, and so on. One of the side effects of urbanization with which engineers and planners must deal with, is the increase of peak flows and volumes of runoff from rainfall events. As a result, the urban drainage and flood control systems must be designed to accommodate the peak flows from a variety of storms that may occur. Usually the peak flow, after development, is required not to exceed what would have occurred from the same storm under conditions existing prior to development. In order to do this it is necessary to design detention storage to hold back runoff and to release it downstream at controlled rates. In the first part of the work have been developed various simplified formulations that can be adopted for the design of stormwater detention facilities. In order to obtain a simplified hydrograph were adopted two approaches: the kinematic routing technique and the linear reservoir schematization. For the two approaches have been also obtained other two formulations depending if the IDF (intensity-duration-frequency) curve is described with two or three parameters. Other formulations have been developed taking into account if the outlet have a constant discharge or it depends on the water level in the pond. All these formulations can be easily applied when are known the characteristics of the drainage system and maximum discharge that these is in the outlet and has been defined a Return Period which characterize the IDF curve. In this way the volume of the detention pond can be calculated. In the second part of the work have been analyzed the design of detention ponds adopting continuous simulation models. The drainage systems adopted for the simulations, performed with SWMM5, are fictitious systems characterized by different sizes, and different shapes of the catchments and with a rainfall historical time series of 16 years recorded in Bologna. This approach suffers from the fact that continuous record of rainfall is often not available and when it is, the cost of such modelling can be very expensive, and that the majority of design practitioners are not prepared to use continuous long term modelling in the design of stormwater detention facilities. In the third part of the work have been analyzed statistical and stochastic methodologies in order to define the volume of the detention pond. In particular have been adopted the results of the long term simulation, performed with SWMM, to obtain the data to apply statistic and stochastic formulation. All these methodologies have been compared and correction coefficient have been proposed on the basis of the statistic and stochastic form. In this way engineers which have to design a detention pond can apply a simplified procedure appropriately corrected with the proposed coefficient.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Large calving events at Greenland's largest outlet glaciers are associated with glacial earthquakes and near instantaneous increases in glacier flow speed. At some glaciers and ice streams, flow is also modulated in a regular way by ocean tidal forcing at the terminus. At Helheim Glacier, analysis of geodetic data shows decimeter-level periodic position variations in response to tidal forcing. However, we also observe transient increases of more than 100% in the glacier's responsiveness to such tidal forcing following glacial-earthquake calving events. The timing and amplitude of the changes correlate strongly with the step-like increases in glacier speed and longitudinal strain rate associated with glacial earthquakes. The enhanced response to the ocean tides may be explained by a temporary disruption of the subglacial drainage system and a concomitant reduction of the friction at the ice-bedrock interface, and suggests a new means by which geodetic data may be used to infer glacier properties. Citation: de Juan, J., et al. (2010), Sudden increase in tidal response linked to calving and acceleration at a large Greenland outlet glacier, Geophys. Res. Lett., 37, L12501, doi: 10.1029/2010GL043289.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Ice sheet thickness is determined mainly by the strength of ice-bed coupling that controls holistic transitions from slow sheet flow to fast streamflow to buttressing shelf flow. Byrd Glacier has the largest ice drainage system in Antarctica and is the fastest ice stream entering Ross Ice Shelf. In 2004 two large subglacial lakes at the head of Byrd Glacier suddenly drained and increased the terminal ice velocity of Byrd Glacier from 820 m yr(-1) to 900 m yr(-1). This resulted in partial ice-bed recoupling above the lakes and partial decoupling along Byrd Glacier. An attempt to quantify this behavior is made using flowband and flowline models in which the controlling variable for ice height above the bed is the floating fraction phi of ice along the flowband and flowline. Changes in phi before and after drainage are obtained from available data, but more reliable data in the map plane are required before Byrd Glacier can be modeled adequately. A holistic sliding velocity is derived that depends on phi, with contributions from ice shearing over coupled beds and ice stretching over uncoupled beds, as is done in state-of-the-art sliding theories.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Thirteen annually resolved accumulation-rate records covering the last similar to 200 years from the Pine Island-Thwaites and Ross drainage systems and the South Pole are used to examine climate variability over West Antarctica. Accumulation is controlled spatially by the topography of the ice sheet, and temporally by changes in moisture transport and cyclonic activity. A comparison of mean accumulation since 1970 at each site to the long-term mean indicates an increase in accumulation for sites located in the western sector of the Pine Island-Thwaites drainage system. Accumulation is negatively associated with the Southern Oscillation Index (Sol) for sites near the ice divide, and periods of sustained negative Sol (1940-42, 1991-95) correspond to above-mean accumulation at most sites. Correlations of the accumulation-rate records with sea-level pressure (SLP) and the SOI suggest that accumulation near the ice divide and in the Ross drainage system may be associated with the midlatitudes. The post-1970 increase in accumulation coupled with strong SLP-accumulation-rate correlations near the coast suggests recent intensification of cyclonic activity in the Pine Island-Thwaites drainage system.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The University of Maine Ice Sheet Model was used to study basal conditions during retreat of the Laurentide ice sheet in Maine. Within 150 km of the margin, basal melt rates average similar to 5 mm a(-1) during retreat. They decline over the next 100km, so areas of frozen bed develop in northern Maine during retreat. By integrating the melt rate over the drainage area typically subtended by an esker, we obtained a discharge at the margin of similar to 1.2 m(3) s(-1). While such a discharge could have moved the material in the Katahdin esker, it was likely too low to build the esker in the time available. Additional water from the glacier surface was required. Temperature gradients in the basal ice increase rapidly with distance from the margin. By conducting upward into the ice all of the additional viscous heat produced by any perturbation that increases the depth of flow in a flat conduit in a distributed drainage system, these gradients inhibit the formation of sharply arched conduits in which an esker can form. This may explain why eskers commonly seem to form near the margin and are typically segmented, with later segments overlapping onto earlier ones.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Assuming a channelized drainage system in steady state, we investigate the influence of enhanced surface melting on the water pressure in subglacial channels, compared to that of changes in conduit geometry, ice rheology and catchment variations. The analysis is carried out for a specific part of the western Greenland ice-sheet margin between 66 degrees N and 66 degrees 30' N using new high-resolution digital elevation models of the subglacial topography and the ice-sheet surface, based on an airborne ice-penetrating radar survey in 2003 and satellite repeat-track interferometric synthetic aperture radar analysis of European Remote-sensing Satellite 1 and 2 (ERS-1/-2) imagery, respectively. The water pressure is calculated up-glacier along a likely subglacial channel at distances of 1, 5 and 9 km from the outlet at the ice margin, using a modified version of Rothlisberger's equation. Our results show that for the margin of the western Greenland ice sheet, the water pressure in subglacial channels is not sensitive to realistic variations in catchment size and mean surface water input compared to small changes in conduit geometry and ice rheology.