Avaliação de tanques de escorva utilizados em substituição à válvula-de-pé em instalações de bombeamento

A maioria das instalações de abastecimento de água utiliza bombas hidráulicas do tipo turbobombas, requerendo que o interior de sua carcaça e da tubulação de sucção esteja preenchido com água (escorvados) para que a sucção da água possa ser efetivada. O escorvamento das bombas pode ser efetuado instalando-as abaixo do reservatório de captação (bomba afogada). Quando a bomba está acima do reservatório e o escorvamento é manual, é necessário usar válvulas-de-pé, que são suscetíveis ao mau funcionamento, limitando a confiabilidade do sistema, principalmente em caso de automação. Como alternativa à válvula-de-pé, neste trabalho, foram estudados dois tanques escorva, testados no Laboratório de Hidráulica e Irrigação da FCAV/UNESP - Jaboticabal, avaliando-se situações de altura manométrica de sucção de bomba centrífuga e relações entre volume útil do tanque e volume do tubo de sucção, tendo-se concluído: a) o volume do tanque de escorva é função do volume do tubo de sucção da instalação de bombeamento e da altura manométrica de sucção; b) o volume do tanque de escorva pode ser calculado seguindo-se a Lei de Boyle, com percentagem de acréscimo que, neste estudo, foi de 10% para um modelo de tanque e de 30% para o segundo modelo.

Uniformidade de distribuição temporal e espacial do KCL na fertirrigação, em um sistema de irrigação por gotejamento

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação de funcionamento das bombas hidráulicas do sistema de tratamento de efluentes da Empresa Parker Hannifin

On the field of the projects of hydraulic systems exists a lot of worries when we talk about the calculate of hydraulic pumps. In this case some facts must be considerate: length of tubes, fluid characteristics, height gauge, temperature, pressure, characteristics of tubes, flow required and others. For that mathematic calculates must be developed with the objective to optimize hydraulic pumps and agree to find an ideal machine (that don't requires more energy than necessary or less energy than it requires; that is the more critical case, cause exists the risk that the fluid pumped do not agree to become in your destiny). The wrong calculate of this machine can super-size its, bringing an excessive energy consumption. Actually it's an important subject because we are in the age of lack of energy what turn it more expensive. So the correct sizing of a hydraulic pump is connected with the fact that you have to uses the enough energy resources avoiding waste. The calculate of ideal pump in the pumping system is studied during years and a lot of specialists in this subject develop equations and theories to calculate its. Some researches study about this subject and all of them become to the same conclusion: to find the ideal pump we have to know the characteristics of fluid (cinematic viscosity), the required flow , overall yield (overall of motor x overall of pump) the high gauge or discharge pressure and the loss of repression. The pressure drop can be calculated with different theories: using Hazen-Williams, Darcy e Weisbach or Chézy (1775 - that starts the researches to calculate the pressure drop). Although the most used theory and what is most near to reality is the Darcy's equation. So, in this job the Darcy's equation were choice to calculate the drop pressure that consider what kind of flow we are studying: laminar or turbulent. The determination of the best pump to be used in the ... ( complete abstract click eletronic access below)

Effect of haematocrit on pump and kidney dysfunction after myocardial revascularization

Objective - Kidney dysfunction is a common complication after cardiac surgery. It occurs in 7 to 31% of the patients. The lowest haematocrit after cardiopulmonary bypass surgery (LHCT) has been identified as a risk factor for kidney dysfunction after cardiac surgery. The aim of this study is to determine whether different levels of haematocrit during cardiopulmonary bypass surgery are related to kidney dysfunction.Methods and results-A prospective study was conducted on consecutive adult patients undergoing myocardial revascularization. Preoperative renal function was assessed by baseline serum creatinine level (CrPre). Peak postoperative creatinine (CrPost) was defined as the highest daily in-hospital postoperative value. Peak fractional change in creatinine (% Delta Cr) was defined as the difference between the CrPre and CrePost represented as a percentage of the preoperative value. The LHTC was defined as the lowest recorded haematocrit prior to weaning from the initial pump run. A category variable was created for haematocrit based on the distribution of values. The category variable had the following cut-off points: less than 23%, 23.1 to 28% and greater than 28.1 %. Lowest haematocrit (26.62 +/- 4.15%), CPB (74.71 +/- 24.90 min), CrPre (1.23 +/- 0.37 mg/dl) and highest CrPost (1.52 +/- 0.47 mg/dl) data varied in near-normal fashion. Statistical significance has been observed in the < 23% lowest haematocrit group (CrIPOD and Cr5POD; P = 0.006) and the 23.1 28% lowest haematocrit level group (CrPre and Cr2POD; P = 0.047). CrPre and Cr5POD did not differ between groups (P > 0.05). The multiple linear regression model confirmed that the determinants for higher %Delta Cr were age, body surface area and preoperative serum creatinine level.Conclusion - The LHTC was not identified as a risk factor for kidney dysfunction after myocardial revascularization.

High-order upwinding and the hydraulic jump

This work is concerned with the computation of incompressible axisymmetric and fall three-dimensional free-surface flows. In particular, the circular-hydraulic jump is simulated and compared with approximate analytic solutions. However, the principal thrust of this paper is to provide a real problem as a test bed for comparing the many existing convective approximations. Their performance is compared; SMART, HLPA and VONOS emerge as acceptable upwinding methods for this problem. Copyright (C) 2002 John Wiley Sons, Ltd.

Pump excited state absorption in holmium-doped fluoride glass

The primary excited state absorption processes relating to the (5)I(6) -> (5)I(7) 3 mu m laser transition in singly Ho(3+)-doped fluoride glass have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the (5)I(6) and (5)I(7) energy levels established the occurrence of two excited state absorption transitions from these energy levels that compete with previously described energy transfer upconversion processes. The (5)I(7) -> (5)I(4) excited state absorption transition has peak cross sections at 1216 nm (sigma(esa)=2.8x10(-21) cm(2)), 1174 nm (sigma(esa)=1x10(-21) cm(2)), and 1134 nm (sigma(esa)=7.4x10(-22) cm(2)) which have a strong overlap with the (5)I(8) -> (5)I(6) ground state absorption. on the other hand, it was established that the excited state absorption transition (5)I(6) -> (5)S(2) had a weak overlap with ground state absorption. Using numerical solution of the rate equations, we show that Ho(3+)-doped fluoride fiber lasers employing pumping at 1100 nm rely on excited state absorption from the lowest excited state of Ho(3+) to maintain a population inversion and that energy transfer upconversion processes compete detrimentally with the excited state absorption processes in concentrated Ho(3+)-doped fluoride glass. (c) 2008 American Institute of Physics.

The hydraulic management of the Barra Bonita reservoir (SP, Brazil) as a factor influencing the temporal succession of its fish community

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Different responses in bulk density and saturated hydraulic conductivity to soil deformation by logging machinery on a Ferralsol under native forest

Ferralsols have high structural stability, although structural degradation has been observed to result from forest to tillage or pasture conversion. An experimental series of forest skidder passes in an east Amazonian natural forest was performed for testing the effects of mechanical stress during selective logging operations on a clay-rich Ferralsol under both dry and wet soil conditions. Distinct ruts formed up to 25 cm depth only under wet conditions. After nine passes the initially very low surface bulk density of between 0.69 and 0.80 g cm(-3) increased to 1.05 g cm(-3) in the wet soil and 0.92 g cm(-3) in the dry soil. Saturated hydraulic conductivities, initially > 250 mm h(-1), declined to a minimum of around 10 mm h(-1) in the wet soil after the first pass, and in the dry soil more gradually after nine passes. The contrasting response of bulk density and saturated hydraulic conductivity is explained by exposure of subsoil material at the base of the ruts where macrostructure rapidly deteriorated under wet conditions. We attribute the resultant moderately high hydraulic conductivities to the formation of stable microaggregates with fine sand to coarse silt textures. We conclude that the topsoil macrostructure of Ferralsols is subject to similar deterioration to that of Luvisols in temperate zones. The stable microstructure prevents marked compaction and decrease in hydraulic conductivity under wetter and more plastic soil conditions. However, typical tropical storms may regularly exceed the infiltration capacity of the deformed soils. In the deeper ruts water may concentrate and cause surface run-off, even in gently sloping areas. To avoid soil erosion, logging operations in sloping areas should therefore be restricted to dry soil conditions when rut formation is minimal.

Drying kinetics of tomato by using electric resistance and heat pump dryers

Drying kinetics of tomato was studied by using heat pump dryer (HPD) and electric resistance dryers with parallel and crossed airflow. The performance of both systems was evaluated and compared and the influence of temperature, air velocity, and tomato type on the drying kinetics was analyzed. The use of HPD showed to be adequate in the drying process of tomatoes, mainly in relation to the conversion rate of electric energy into thermal energy. The heat pump effective coefficient of performance (COPHT,EF) was between 2.56 and 2.68, with an energy economy of about 40% when compared to the drying system with electric resistance. The Page model could be used to predict drying time of tomato and statistical analysis showed that the model parameters were mainly affected by drying temperature.

Installation of a getter vacuum pump in cathode-anode region of a high-power klystron amplifier - Propose and feasible

The possibility to install a getter vacuum pump and its feasible in the anode of a high-power klystron amplifier is investigated in order to decrease of the pressure in the gun and consequently increasing its lifetime. The study is conducted using a 1.3 GHz, 100 A and 240 kV high-power klystron with five reentrant coaxial cavities, assembled in a cylindrical drift tube 1.2 m long. This work takes into account the specific conductance of components of gun and all important gas sources, like the degassing of the drift tube, the cavity walls, the cathode, the anode, and the collector, as well the position and pumping speed of the getter vacuum pump in anode region. © 2006 IEEE.

Electro-hydraulic actuator tester for fly-by-wire aircrafts

An 8051-based microcontroller tester has been designed to reduce troubleshooting time of the Electro-Hydraulic Actuators (EHA) installed in fly-by-wire aircrafts. The tester algorithm first evaluates EHA pressure and position sensor signals to emit either a pass or fail message. The evaluation is based on predefined ranges of EHA pressure and position signals. Next, the instrument tests the EHA response capability - a way of dynamic response evaluation, again issuing a suitable response. The instrument proved to be reliable after being successfully evaluated in laboratory and in a real model test airplane. © 2007 IEEE.

Desempeño de tanques decantadores de sólidos en un sistema de recirculación para producción de tilapia

To compare the removal efficiency of solids, turbidity and apparent color between a conventional and a column settling tanks in a recirculating aquaculture system (RAS) for tilapia farming. Materials and methods. Tilapia with a stocking density between 30 and 33 kg/m3 were cultured in a RAS consisting of a water level control box, PVC piping system, three plastic tanks for culture, conventional horizontal flow settling tank (Con.ST), column vertical flow settling tank (Col.ST), three phase fluidized bed reactor, oxygen transfer reactor, air compressor, air blower, centrifugal pump. The Con.ST operated at a volume of 1.4 m3 and hydraulic retention time (HRT) of 2.94 h; and was drained weekly for washing and sludge collection, representing a 55%discharge of system water volume. The Col.ST operated with a volume of 0.30 m3 and HRT of 0.553 h. Three daily partial draining operations were executed, representing a discharge of 50% of the system volume. Results. The mean solids removal efficiencies were: 34.01 and 44.44%for total solids; 64.45 and 71.71% for suspended solids; 21.10 and 45.65% volatile solids; 65.51% and 62.79% for turbidity; and 56.37 and 50.91% for apparent color, respectively for Con.ST and Col.ST. Conclusions. The two settling devices are useful on removal of the studied parameters and presented similar performance on turbidity and apparent color removal; however, the Col.ST was more efficient than Con.ST for solids removal, requires less space, less volume and requires less discharge water volume, displaying feasibility for its use on RAS.

Modelagem para dimensionamento de tanque de escorva para instalações de bombeamento utilizando a Lei de Boyle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização hidrogeológica e simulação numérica de fluxo em uma região situada no distrito industrial de Paulínia (SP)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparação econômica entre critérios de dimensionamento de sistemas de irrigação por microaspersão utilizando modelos de programação linear

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA