scholarly journals Irrigation canals in Melo creek basin (Rio Espera and Capela Nova municipalities, Minas Gerais, Brazil): habitats to Biomphalaria (Gastropoda: Planorbidae) and potential spread of schistosomiasis

2016 ◽  
Vol 76 (3) ◽  
pp. 638-644 ◽  
Author(s):  
M. G. P. Leite ◽  
E. C. Pimenta ◽  
M. A. G. Fujaco ◽  
E. M. Eskinazi-Sant'Anna
Keyword(s):  
Flow Rate ◽  
Seasonal Cycle ◽  
Specific Growth ◽  
Minas Gerais ◽  
Low Flow ◽  
Hydraulic Characteristics ◽  
Irrigation Canals ◽  
Hydrographic Basin ◽  
Minas Gerais State ◽  
Anthropogenic Action

Abstract This study analyzed the presence of Biomphalaria in Melo creek basin, Minas Gerais state, and its relationship to irrigation canals. Seventeen of these canals were used to determine a limnological, morphological and hydrological characterization during an annual seasonal cycle. Biomphalaria samples were sent to René Rachou Research Center/FIOCRUZ for identification and parasitological examination. Six canals were identified as breeding areas for mollusks and in one of them it was registered the coexistence of B. tenagophila (first report to this basin) and B. glabrata species. Results indicated that the low flow rate and speed of water flow were the main characteristics that contributed to this specific growth of the mollusks in the area. These hydraulic characteristics were created due to anthropogenic action through the canalization of lotic areas in Melo creek, which allowed ideal ecological conditions to Biomphalaria outbreak. The results emphasize the need of adequate handling and constant monitoring of the hydrographic basin, subject to inadequate phytosanitary conditions, aiming to prevent the occurrence and propagation of schistosomiasis.

Hydraulic Characteristics of Pipelines Transporting Hot Waxy Crudes

2006 ◽  
Author(s):  
Jun Chen ◽  
Jinjun Zhang ◽  
Hongying Li
Keyword(s):  
Flow Rate ◽  
Pour Point ◽  
Friction Loss ◽  
Low Flow ◽  
Critical Flow ◽  
Outlet Temperature ◽  
Hydraulic Characteristics ◽  
Critical Flow Rate ◽  
Waxy Crude ◽  
Oil Pipeline

Waxy crudes are generally pipelined by means of heating. In general, the friction loss of a pipeline decreases with decreasing flow rate. This is the case of isothermal pipeline. However, a hot oil pipeline operated at low flow rate might show a contrary case, i.e. friction-loss increases with decreasing flow rate. This is an unstable operation state and may result in disastrous consequence of flow ceasing if tackled improperly. For a waxy crude pipeline, this may also be exaggerated by the non-Newtonian flow characteristics at temperatures near the pour point. That is to say, there may exist a critical flow rate for pipelines transporting heated waxy crude, and in order to ensure safe operation, the flow rate of a pipeline transporting hot oil should be no less than this critical flow rate. Based on theoretical analysis and can study, the hydraulic characteristics of pipelines transporting hot waxy crudes was investigated, and an empirical model was developed correlating the critical flow rate QC and the pipelining parameters, such as the average overall heat transfer coefficient, the ground temperature, the heating temperature, etc. Another relationship was found between TZC, the outlet temperature of the pipeline corresponding to the critical flow rate, and the critical flow rate. This TZC is also the lowest pipeline outlet temperature that ensures the normal pipelining operation state. Case study on a 720mm O.D. pipeline transporting heated Daqing waxy crude with a pour point of 36 °C showed that the TZC was in a range of 31∼34.2°C.

Two-Objective Shape Optimization of Sewers

2008 ◽  
Author(s):  
T. Karvinen ◽  
R. Karvinen
Keyword(s):  
Shape Optimization ◽  
Flow Velocity ◽  
Flow Rate ◽  
Optimization Problem ◽  
Volume Flow Rate ◽  
Optimal Solution ◽  
Volume Flow ◽  
Low Flow ◽  
Hydraulic Characteristics ◽  
Analytical Treatment

Hydraulic characteristics of different sewer shapes are studied. The sewer must carry a very large flow rate for example in storm conditions, but most of the time there is very little flow at the bottom. This causes sedimentation of particles, which is avoided by having a high flow velocity. These are contradicting objectives in sewer design and therefore yield a multi-objective optimization problem. It is shown using a shape optimization procedure, that hydraulic characteristics of existing sewers can be improved. Using the optimization scheme, the Pareto-optimal solution of a shape optimization problem is found, for which the objectives are maximizing the flow velocity at low flow rates and maximizing the volume flow rate when the sewer is full. If the volume flow rate is to be maximized, almost a square cross-section is the best and the lower part of the sewer is very narrow if the velocity at the bottom is to be maximized. Hydraulic characteristics of sewers of different shapes are compared. In order to obtain optimal results in a reasonable time, an analytical treatment using the Manning formula is adopted and its results are compared with a numerical solution. Traditionally, in this kind of analysis the friction factor in the Manning formula is assumed constant. The validity of this assumption is confirmed using numerical modeling of flow (CFD).

scholarly journals DENSIDADE DE COLETA DE DADOS E SUA INFLUÊNCIA NA CARACTERIZAÇÃO DA UNIFORMIDADE EM PIVÔ CENTRAL LEPA

Irriga ◽  
2007 ◽  
Vol 12 (3) ◽  
pp. 297-306 ◽  
Author(s):  
Everardo Chartuni Mantovani ◽  
Marconi Batista Teixeira ◽  
Márcio Mota Ramos ◽  
Rubens Alves de Oliveira ◽  
Darik Oliveira Souza
Keyword(s):  
Flow Rate ◽  
Irrigation System ◽  
Distribution Coefficients ◽  
Minas Gerais ◽  
Evaluation Methodology ◽  
Irrigation Systems ◽  
Evaluation Methodologies ◽  
Observation Area ◽  
Minas Gerais State ◽  
Collection Time

DENSIDADE DE COLETA DE DADOS E SUA INFLUÊNCIA NA CARACTERIZAÇÃO DA UNIFORMIDADE EM PIVÔ CENTRAL LEPA  Everardo Chartuni Mantovani1; Marconi Batista Teixeira2; Márcio Mota Ramos1; Rubens Alves de Oliveira1; Darik Oliveira Souza11Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa,MG, [email protected] de Engenharia Rural, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP  1 RESUMO Este trabalho foi desenvolvido com o objetivo de propor uma metodologia para avaliação de um sistema de irrigação por pivô central equipado com emissores do tipo LEPA. Um dispositivo para medição da vazão do emissor LEPA foi desenvolvido para operar em condições de campo. As medições de vazão foram feitas em todos os bocais, com os pivôs posicionados em aclive eem declive. Emseguida, determinou-se a percentagem de emissores (100, 50, 33 ou 25%) a ser avaliados para otimizar o tempo de coleta, sem comprometer os coeficientes de uniformidade. Os testes para o desenvolvimento do dispositivo e das metodologias propostas para avaliação de pivô central equipado com emissor tipo LEPA foram realizados na Área de Observação e Pesquisaem Cafeicultura Irrigada(PNP&D-Café/DEA-UFV/VALMONT), localizada no município de Paula Cândido, Minas Gerais. Com o intuito de comprovar a praticidade do dispositivo desenvolvido e as metodologias propostas, foram avaliados seis sistemas de irrigação localizados nos municípios de Patrocínio, Estrela do Sul e Uberlândia, na região do Triângulo Mineiro. De acordo com os resultados, não houve necessidade de medir a vazão de todos os emissores para avaliação dos coeficientes de uniformidade de Christiansen e de distribuição, podendo-se avaliar somente 50% dos emissores, pois esta metodologia não diferiu significativamente daquela usada para avaliar todos os emissores. UNITERMOS: coeficientes de uniformidade, café, emissores  MANTOVANI, E. C.; TEIXEIRA, M. B.; RAMOS, M. M.; OLIVEIRA, R.A. de; SOUZA, D. O. EVALUATION  METHODOLOGY FOR CENTRAL PIVOT IRRIGATION EQUIPPED WITH LEPA  2 ABSTRACT A study was carried out to propose an evaluation methodology for a central pivot irrigation system equipped with LEPA-type emitters. A device to measure the flow rate of the LEPA emitter was developed to operate under field conditions. The measurements of the flow rate were performed in all nozzles of central pivots positioned at acclivity and slope. Then, the percentage of the evaluated emitters (100, 50, 33 and 25%) was determined in order to optimize the collection time without influencing the uniformity coefficients. The tests for the  development of the device and the proposed evaluation methodologies for central pivot irrigation system equipped with the LEPA-type emitter were carried out at the Irrigated Coffee Growth,  Research and Observation Area (PNP&D-Café/DEA-UFV/VALMONT), located in Paula Cândido county, Minas Gerais State, Brazil. To verify the feasibility of the developed device and the proposed methodologies, six irrigation systems located in Patrocínio, Estrela do Sul, and Uberlândia counties, in Triângulo Mineiro region were evaluated. According to the results, there is no need to measure the flow rate from all emitters to evaluate the Christiansen uniformity coefficients and the distribution coefficients, and just the evaluation of 50% emitters is enough since this methodology did not significantly differ from the methodology used to evaluate all emitters. KEYWORDS: coefficient uniformity, coffee, nozzles

Stabilization of the Speed of the Hydraulic Motor Through Throttle Compensation for Volume Losses

2020 ◽  
Vol 26 (3) ◽  
pp. 126-130
Author(s):  
Krasimir Kalev
Keyword(s):  
Flow Rate ◽  
Hydraulic Drive ◽  
Pressure Change ◽  
Operating Conditions ◽  
Drive System ◽  
Inlet Pressure ◽  
Schematic Diagram ◽  
Hydraulic Characteristics ◽  
Hydraulic Motor ◽  
Flow Through

AbstractA schematic diagram of a hydraulic drive system is provided to stabilize the speed of the working body by compensating for volumetric losses in the hydraulic motor. The diagram shows the inclusion of an originally developed self-adjusting choke whose flow rate in the inlet pressure change range tends to reverse - with increasing pressure the flow through it decreases. Dependent on the hydraulic characteristics of the hydraulic motor and the specific operating conditions.

scholarly journals Extreme rainfall and its impacts in the Brazilian Minas Gerais state in January 2020: Can we blame climate change?

2021 ◽  
Author(s):  
Ricardo Dalagnol ◽  
Carolina B. Gramcianinov ◽  
Natália Machado Crespo ◽  
Rafael Luiz ◽  
Julio Barboza Chiquetto ◽  
...  
Keyword(s):  
Climate Change ◽  
Extreme Rainfall ◽  
Minas Gerais ◽  
Minas Gerais State

scholarly journals Backflow effects on mass flow gain factor in a centrifugal pump

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042199886
Author(s):  
Wenzhe Kang ◽  
Lingjiu Zhou ◽  
Dianhai Liu ◽  
Zhengwei Wang
Keyword(s):  
Centrifugal Pump ◽  
Mass Flow ◽  
Flow Rate ◽  
Low Frequency ◽  
Gain Factor ◽  
Low Flow ◽  
Cavity Volume ◽  
Cavitating Flows ◽  
Inlet Tube ◽  
Low Flow Rate

Previous researches has shown that inlet backflow may occur in a centrifugal pump when running at low-flow-rate conditions and have nonnegligible effects on cavitation behaviors (e.g. mass flow gain factor) and cavitation stability (e.g. cavitation surge). To analyze the influences of backflow in impeller inlet, comparative studies of cavitating flows are carried out for two typical centrifugal pumps. A series of computational fluid dynamics (CFD) simulations were carried out for the cavitating flows in two pumps, based on the RANS (Reynolds-Averaged Naiver-Stokes) solver with the turbulence model of k- ω shear stress transport and homogeneous multiphase model. The cavity volume in Pump A (with less reversed flow in impeller inlet) decreases with the decreasing of flow rate, while the cavity volume in Pump B (with obvious inlet backflow) reach the minimum values at δ = 0.1285 and then increase as the flow rate decreases. For Pump A, the mass flow gain factors are negative and the absolute values increase with the decrease of cavitation number for all calculation conditions. For Pump B, the mass flow gain factors are negative for most conditions but positive for some conditions with low flow rate coefficients and low cavitation numbers, reaching the minimum value at condition of σ = 0.151 for most cases. The development of backflow in impeller inlet is found to be the essential reason for the great differences. For Pump B, the strong shearing between backflow and main flow lead to the cavitation in inlet tube. The cavity volume in the impeller decreases while that in the inlet tube increases with the decreasing of flow rate, which make the total cavity volume reaches the minimum value at δ = 0.1285 and then the mass flow gain factor become positive. Through the transient calculations for cavitating flows in two pumps, low-frequency fluctuations of pressure and flow rate are found in Pump B at some off-designed conditions (e.g. δ = 0.107, σ = 0.195). The relations among inlet pressure, inlet flow rate, cavity volume, and backflow are analyzed in detail to understand the periodic evolution of low-frequency fluctuations. Backflow is found to be the main reason which cause the positive value of mass flow gain factor at low-flow-rate conditions. Through the transient simulations of cavitating flow, backflow is considered as an important aspect closely related to the hydraulic stability of cavitating pumping system.

Assessment of the Use of Humidified Nasal Cannulas for Oxygen Therapy in Patients with Epistaxis

ORL ◽  
2021 ◽  
pp. 1-5
Author(s):  
Jingjing Liu ◽  
Tengfang Chen ◽  
Zhenggang Lv ◽  
Dezhong Wu
Keyword(s):  
Flow Rate ◽  
Oxygen Therapy ◽  
Preliminary Investigation ◽  
Nasal Cannula ◽  
Low Flow ◽  
Antiplatelet Drugs ◽  
Flow Rates ◽  
The Past ◽  
Oxygen Inhalation ◽  
Significant Difference

<b><i>Introduction:</i></b> In China, nasal cannula oxygen therapy is typically humidified. However, it is difficult to decide whether to suspend nasal cannula oxygen inhalation after the nosebleed has temporarily stopped. Therefore, we conducted a preliminary investigation on whether the use of humidified nasal cannulas in our hospital increases the incidence of epistaxis. <b><i>Methods:</i></b> We conducted a survey of 176,058 inpatients in our hospital and other city branches of our hospital over the past 3 years and obtained information concerning their use of humidified nasal cannulas for oxygen inhalation, nonhumidified nasal cannulas, anticoagulant and antiplatelet drugs, and oxygen inhalation flow rates. This information was compared with the data collected at consultation for epistaxis during these 3 years. <b><i>Results:</i></b> No significant difference was found between inpatients with humidified nasal cannulas and those without nasal cannula oxygen therapy in the incidence of consultations due to epistaxis (χ<sup>2</sup> = 1.007, <i>p</i> &#x3e; 0.05). The same trend was observed among hospitalized patients using anticoagulant and antiplatelet drugs (χ<sup>2</sup> = 2.082, <i>p</i> &#x3e; 0.05). Among the patients with an inhaled oxygen flow rate ≥5 L/min, the incidence of ear-nose-throat (ENT) consultations due to epistaxis was 0. No statistically significant difference was found between inpatients with a humidified oxygen inhalation flow rate &#x3c;5 L/min and those without nasal cannula oxygen therapy in the incidence of ENT consultations due to epistaxis (χ<sup>2</sup> = 0.838, <i>p</i> &#x3e; 0.05). A statistically significant difference was observed in the incidence of ENT consultations due to epistaxis between the low-flow nonhumidified nasal cannula and nonnasal cannula oxygen inhalation groups (χ<sup>2</sup> = 18.428, <i>p</i> &#x3c; 0.001). The same trend was observed between the 2 groups of low-flow humidified and low-flow nonhumidified nasal cannula oxygen inhalation (χ<sup>2</sup> = 26.194, <i>p</i> &#x3c; 0.001). <b><i>Discussion/Conclusion:</i></b> Neither high-flow humidified nasal cannula oxygen inhalation nor low-flow humidified nasal cannula oxygen inhalation will increase the incidence of recurrent or serious epistaxis complications; the same trend was observed for patients who use anticoagulant and antiplatelet drugs. Humidification during low-flow nasal cannula oxygen inhalation can prevent severe and repeated epistaxis to a certain extent.

Paleoenvironmental reconstruction of the headwaters of the preto river, Minas Gerais state, Brazil, through siliceous bioindicators

2021 ◽  
Vol 108 ◽  
pp. 103349
Author(s):  
David Oldack Barcelos Ferreira Machado ◽  
Karina Ferreira Chueng ◽  
Heloisa Helena Gomes Coe ◽  
Alexandre Christófaro Silva ◽  
Camila Rodrigues Costa
Keyword(s):  
Minas Gerais ◽  
Paleoenvironmental Reconstruction ◽  
Minas Gerais State
Sign in / Sign up

Export Citation Format

Share Document