scholarly journals Analyzing the bias in dry weather spot flow rates to periodical mean flow rates in mountain streams: toward determining water pollution loads and optimizing water sampling strategies

2021 ◽  
Vol 15 (2) ◽  
pp. 31-36
Author(s):  
Ami Tanno ◽  
Shigeki Harada
Keyword(s):  
Water Pollution ◽  
Mountain Streams ◽  
Sampling Strategies ◽  
Water Sampling ◽  
Mean Flow ◽  
Flow Rates ◽  
Pollution Loads

scholarly journals Increased take-off level in automatic milking systems – effects on milk flow, milk yield and milking efficiency at the quarter level

2018 ◽  
Vol 86 (1) ◽  
pp. 85-87 ◽  
Author(s):  
Sabine Ferneborg ◽  
Måns Thulin ◽  
Sigrid Agenäs ◽  
Kerstin Svennersten-Sjaunja ◽  
Peter Krawczel ◽  
...  
Keyword(s):  
Flow Rate ◽  
The Other ◽  
Mean Flow ◽  
Flow Rates ◽  
Decline Phase ◽  
Flow Profiles ◽  
Milk Flow ◽  
Automatic Milking ◽  
Automatic Milking Systems ◽  
Time Required

AbstractThis research communication describes how different detachment levels (0.48, 0.3 and 0.06 kg milk/min) at the quarter-level affect milk flow profiles and overall milking efficiency in automatic milking systems. We hypothesized a higher detachment level would result in greater mean flow rates without affecting the volume of harvested milk per cow during 24 h compared to lower detachment levels. The data suggest milk flow decreased to a rate below the overmilking limit within the 6-s delay time required for termination in all treatments, but the duration of overmilking was shorter for the greatest detachment level compared to the other treatments. We conclude that setting a detachment level at a greater milk flow rate reduces the duration of overmilking without affecting the amount of milk harvested when applied to cows in mid-lactation during quarter-level milking. We also suggest that the steepness of the decline phase of the milk flow curve might have a larger effect than the actual detachment level on the duration of overmilking.

scholarly journals LAYOUT AND DESIGN SOLUTIONS OF FILTERING WATER INTAKES FROM SHALLOW WATERCOURSES FOR DRIP IRRIGATION SYSTEMS

2021 ◽  
Author(s):  
A. S. Shtanko ◽  
◽  
V. N. Shkura ◽  
Keyword(s):  
Water Intake ◽  
Drip Irrigation ◽  
Agricultural Development ◽  
Drainage Water ◽  
Low Flow ◽  
Mountain Streams ◽  
Irrigation Systems ◽  
Flow Rates ◽  
Hydrographic Features ◽  
Sand And Gravel

Purpose: development of layout and design schemes for low-flow water intakes, arranged on shallow river and stream watercourses for supplying water to drip irrigation systems. Agricultural development of terraces and floodplains of small foothill and mountain streams actualizes the development of facilities for water intake from them for the purpose of irrigating land. Morphological and hydrographic features, including shallow low-water depths, high flow rates, flow rates variability, saturation with sediments, the presence of underflow and overflow runoff, etc., make water intake from such watercourses difficult and specific. These circumstances predetermine the relevance of water intake structures development corresponding to the specified conditions. Materials and Methods. When developing the layout and design schemes of low-flow water intakes from shallow watercourses, the technologies of exploratory design of engineering systems and structures were used. Results. With regard to the morphometric, hydrological and other conditions of shallow foothill and mountain streams, a water intake with a bottom water intake was adopted for development. The water intake part of headworks is designed in the form of a toe drain, which has under-flow and overflow intake parts that allow water intake from the channel and off-channel water streams. The toe is made of two or three layers of sand and gravel material. Drainage pipes or pipe filters are used as a drainage element. Depending on the conditions of the watercourse, water intakes with transverse, longitudinal and pocket-coastal placement of water intakes are proposed. Conclusion. The layout and design schemes of filtering water intakes from shallow watercourses based on the use of overflow, underflow and combined structures of multilayer drainage water intakes with stream (transverse and longitudinal) and off-channel (pocket-coastal) placement have been proposed and developed.

P4379Pathophysiology of left atrial filling in mitral regurgitation. A new volumetric flow rate index describing disturbed left atrial filling behavior in mitral regurgitation by 3D TTE

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
D Frumkin ◽  
K Stangl ◽  
A Muegge ◽  
T Buck ◽  
B Plicht
Keyword(s):  
Mitral Regurgitation ◽  
Left Atrium ◽  
Flow Rate ◽  
Left Atrial ◽  
Volume Overload ◽  
Volumetric Flow Rate ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Mean Flow ◽  
Flow Rates

Abstract Background In chronic mitral regurgitation (MR) the left atrium (LA) is one of the first cardiac structures involved in remodeling by progressive volume overload. Real-time three-dimensional echocardiography is able to monitor volumetric changes of the left atrium during the heart cycle. Purpose We hypothesized that chronic volume overload due to MR leads to detectable changes in the LA filling behavior described by mean and maximum filling flow rates and their relation called volumetric flow rate index. Methods We prospectively analyzed data of 36 patients in different stages of chronic MR and 13 patients without MR. Transthoracic echocardiography was conducted using the Epiq 7G Ultrasound System. Standard 2D- and 3D apical 4-chamber views were recorded and stored for offline analysis. We generated volume-time-curves by 3D volume analysis to derive mean and maximum volumetric flow rates during LA reservoir, conduit and pump phase. Volumetric flow rate index was calculated as the quotient of mean flow rate/maximum flow rate. Results Average MR severity, calculated with the MR Scoring system introduced from Buck et al. and implicated in the ESC Guidelines, was 6.2 points (±2.5) according to Grade I-II. We included 13 patients without MR, 18 with mild MR, 12 patients with moderate MR, 6 patients with severe MR. Left ventricular ejection fraction was similar in the different groups (51,2±12,3%). Maximum and mean flow rate showed no significant correlation with MR severity. Correlation of MR severity with LA dilation (ml/m2 BSA) was r=0.41; p<0.001. Flow rate index showed strong significant correlation with MR severity in left atrial reservoir phase (r=−0.75; p<0.001). There was no statistically relevant difference of volumetric flow rate parameters in left atrial pump and conduit phase. Line chart Conclusions We observed a significant correlation of the volumetric flow rate index to MR severity in the left atrial reservoir phase with stronger correlation than MR severity to left atrial dilation. The results of this work encourage further investigations to establish the presented volumetric flow rate index as a progression marker of MR and to evaluate its prognostic value.

LDV Measurements and Investigation of Flow Field Through Radial Turbine Guide Vanes

1991 ◽  
Vol 113 (4) ◽  
pp. 660-667
Author(s):  
Hasan Eroglu ◽  
Widen Tabakoff
Keyword(s):  
Flow Field ◽  
Flow Direction ◽  
Mean Flow ◽  
Flow Rates ◽  
Radial Turbine ◽  
Contour Plots ◽  
Mass Flow Rates ◽  
Flow Turbulence ◽  
Downstream Flow ◽  
Nozzle Blade

The results of LDV measurements and investigation of the detailed flow field in a radial inflow turbine nozzle are presented. The flow velocities were measured at upstream, inside and downstream of the nozzle blades for two different mass flow rates, using a three-component LDV system. Results are presented as contour plots of mean velocities, flow angles, and turbulence intensities. The flow field inside the nozzle blade passages was found to be influenced by the upstream scroll geometry. The flow turbulence increased in the downstream flow direction. The LDV mean flow results on the blade-to-blade midspan plane which is parallel to the end walls were also compared with an inviscid, “panel method” solution.

Mechanics of machine milking: II. The flow-rate pattern within single pulsation cycles

1966 ◽  
Vol 33 (2) ◽  
pp. 177-191 ◽  
Author(s):  
C. C. Thiel ◽  
P. A. Clough ◽  
D. R. Westgarth ◽  
D. N. Akam
Keyword(s):  
Flow Rate ◽  
Response Rate ◽  
Sphincter Muscle ◽  
Mean Flow ◽  
Considerable Time ◽  
Flow Rates ◽  
Machine Milking ◽  
Closing Force ◽  
The Mean ◽  
Pulsation Cycle

SummaryThe milk flowing during a single pulsation cycle was collected in a circle of contiguous cups which rotated in a chamber at 1 rev/pulsation cycle just below the end of the teatcup liner. The mean flow rate during the time taken for each collecting cup to pass under the milk stream was calculated and the flow-rate curve for the milkflow period of the pulsation cycle plotted. Flow rates were measured at 130, 97, 65, 32 and 16 c/min, and also after the pulsator had been stopped with the liner open for 0·5 min (0 pulsation).It was concluded from the series of flow-rate curves at the different pulsation rates that flow rate from the teat increased in about 0·05 sec to a steady value which continued for 0·5 sec or so, and then declined over a period of about 1·5 sec to a new constant value approximately equal to that shown after milk had flowed continuously from the teat for 0·5 min.These results suggest that once the pressure difference across the streak canal during milking forces the teat sphincter open a considerable time elapses before the muscle control system responds, and that a further much longer period elapses before the full closing force of the sphincter is exerted. Thus, it would appear that at pulsation rates of about 50 c/min and above, the streak canal is closed by pressure exerted on the teat by the closing liner, the sphincter muscle playing no active part because its response rate is slow compared with the pulsation rate. At lower pulsation rates the flow rate declines during each cycle because the sphincter muscle has time to exert a closing force to a greater or lesser extent depending on the duration of the milkflow period.

scholarly journals In vitro estimation of the energy loss through turbulence in a porcine aortic valve stenosis model and silicone ascending aorta phantom using backlight particle tracking velocimetry

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
M Chiarelli ◽  
S F De Marchi ◽  
D Obrist ◽  
E Buffle
Keyword(s):  
Left Ventricle ◽  
Aortic Stenosis ◽  
Energy Loss ◽  
Particle Tracking Velocimetry ◽  
Ascending Aorta ◽  
Low Flow ◽  
Mean Flow ◽  
Flow Rates ◽  
Stenosis Severity

Abstract Introduction Patients suffering from low-flow, low-gradient aortic stenosis present a decreased stroke volume due to decreased contraction or relaxation function of the left ventricle. As a low stroke volume tends to cause a low transvalvular flow, transvalvular pressure gradient (TVPG) and effective orifice area, the clinician cannot rely on those parameters with confidence for the evaluation of aortic stenosis severity. Hence new diagnostic parameters have to be developed. Energy loss through turbulence associated with aortic stenosis represented the wasted left ventricle work. Currently, echocardiographic measurement of the turbulence intensity is not validated for clinical evaluations of aortic stenosis. Methods Two porcine aortic valves were harvested and inserted in a flow loop that replicates the pulsatile flow of the heart. A stiffening of the valves was achieved by treating them with formaldehyde. The stiffening was externally confirmed by a custom-made force-displacement device quantifying the rigidity of the leaflet yielding two stiffness grades per valve. Each valve was tested under three different mean flow rates (1, 2.5, and 4 l/min) at each of the two stiffness grades. Moreover the pressure in the left ventricle chamber and in the aortic chamber was recorded to calculate the TVPG. Particle tracking velocimetry measurements into the transparent silicone ascending aorta phantom allowed the computation of the turbulent kinetic energy (TKE), to evaluate the energy loss due to turbulence. Results We could confirm the enhanced rigidity of the valve leaflets with our custom device (data not shown) and measure a consistent increase in TVPG across all mean flow rates between the two stiffness grades. Moreover, an explicit increase of the TKE in the aortic phantom could be measured after the stiffening process (73.1% under 1 l/min, and 43% under both 2.5 and 4 l/min). In addition, a good correlation (R = 0.86) between the mean TVPG and the TKE was found. Conclusions This project demonstrated the possibility of quantifying the energy loss attributed to turbulence for porcine valves in vitro for native and added stiffness grade. This project lays the foundation for the development of a new diagnostic tool for the assessment of stenosis severity in patients with low-flow, low-gradient aortic stenosis in cardiac imaging tool such as echocardiography. FUNDunding Acknowledgement Type of funding sources: None. TVPG and its correlation with TKE Intensity graphs of the TKE

scholarly journals Areal and Temporal Variation of Percolation of Water Through a Snow-Pack

1977 ◽  
Vol 19 (81) ◽  
pp. 668
Author(s):  
E. J. Langham
Keyword(s):  
Temporal Variation ◽  
Flow Rate ◽  
Lower Surface ◽  
Snow Melt ◽  
Snow Pack ◽  
Mean Flow ◽  
Flow Rates ◽  
Melt Water ◽  
Temporal And Spatial ◽  
True Measure

Abstract Snow melt water that is uniformly generated over the upper surface of the snow-pack does not percolate homogeneously through the snow. Consequently, the rate of arrival of melt water at a single collector at the lower surface does not give a true measure of the melt rate. The experiment described here measures the spatial variability of flow rate and the temporal variation of this two-dimensional pattern. Data are collected from an array of 64 sensors under control of a microprocessor. The microprocessor checks the consistency of the data, calculates the flow rate for each sensor and transfers the results to a recorder. These mean flow rates are calculated at regular intervals for the duration of the experiment. In this way the temporal and spatial variations of flow rate may be related to variations in meteorological conditions and the evolution of the structure snow-pack as the melting progresses.

scholarly journals An Experimental Study of the Flow Field Inside the Diffuser Passage of a Laboratory Centrifugal Pump

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Qiaorui Si ◽  
Patrick Dupont ◽  
Annie-Claude Bayeul-Lainé ◽  
Antoine Dazin ◽  
Olivier Roussette ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Design Flow ◽  
Low Flow ◽  
Mean Flow ◽  
Local Pressure ◽  
Flow Rates ◽  
Piv Measurement ◽  
Measurement Results

Measurements are processed on a centrifugal pump model, which works with air and performs with the vane-island type diffuser of a real hydraulic pump, under five flow rates to investigate the internal flow characteristics and their influence on overall pump performance. The mean flow characteristics inside the diffuser are determined by using a miniature three-hole probe connected to an online data acquisition system. The flow structure at the inlet section of the diffuser is analyzed in detail, with a focus on the local pressure loss inside the vaneless gap and incidence angle distributions along the hub-to-shroud direction of the diffuser. Some existing calculations, including leakage effects, are used to evaluate the pressure recovery downstream of the impeller. Furthermore, particle image velocimetry (PIV) measurement results are obtained to help analyze the flow characteristics inside the vane-island diffuser. Each PIV measuring plane is related to one particular diffuser blade-to-blade channel and is analyzed by using the time-averaged method according to seven different relative positions of the impeller. Measurement results show that main loss is produced inside the vaneless part of the diffuser at low flow rates, which might have been caused by the strong rotor–stator interaction. When the impeller flow rate is greater than the diffuser design flow rate, a large fluctuating separated region occurs after the throat of the diffuser on the pressure side. Mean loss originates from the unsteady pressure downstream of the diffuser throat. For better characterization of the separations observed in previous experimental studies, complementary unsteady static pressure measurement campaigns have been conducted on the diffuser blade wall. The unsteadiness revealed by these measurements, as well as theirs effects on the diffuser performance, was then studied.

Sign in / Sign up

Export Citation Format

Share Document