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Purpose To investigate whether a metabolic cart using a flowmeter in the upper range of accepted resistance to airflow (, Physiological Reports, 9 (7), ISSN:2051-817X

In order to investigate a self-excited oscillatory phenomenon of a two-dimensional confined jet with a cylinder as a downstream target, the authors conduct two-dimensional numerical analyses based on vorticity ζ and stream function ψ using a finite-difference discretisation method. At first, confirming the reliability and accuracy of the present analyses, the authors examine two kinds of preliminary tests prior to the main test. Aa a result, the authors reveal (1) the two-dimensionality of the phenomenon by comparing computations with experiments, and (2) the importance and complexity of the upstream of the downstream target.

Purpose: To evaluate the impact of voiding position on uroflowmetry parameters and to assess its potential clinical implications. Materials and Methods: We conducted a prospective study from 2013 to 2015 and included men between 18 and 77 years old who were either healthy volunteers with an International Prostate Symptom Score (IPSS) ≤7 or men with benign prostate enlargement that were on alpha-blocker medication and had an IPSS ＜10. Participants underwent uroflowmetry and post-void residual urine (PVRU) measurements twice, once in a sitting position and once in a standing position. The participants were divided into 4 groups based on age (35 years or younger, 36 to 50 years, 51 to 60 years, and older than 60 years). Results: A total of 740 men with a mean age of 40.35 years were evaluated. There was no significant difference in uroflowmetry parameters until the age of 50 years between the voiding positions. However, in those older than 50 years, PVRU volume was significantly lower in the sitting position than the standing position, whereas voiding time was significantly higher in the sitting position than the standing position. Other uroflowmetry parameters, including maximal and average urine flow rates, were non-significant. Conclusions: The voiding position plays an important role in the uroflowmetry parameters of elderly men. Voiding in the sitting position was found to be optimal for elderly men, whereas the role of the voiding position in healthy young men could not be determined. More research is needed to further study this issue.

The real-time monitoring of fluid properties in tubular systems, such as viscosity and flow rate, is essential for industries utilizing liquid mediums. Nowadays, most studies of the fluid characteristics are performed off-line using laboratory facilities that can provide accurate results, yet they do not match the demanded industrial pace. Off-line measurements are ineffective and time-consuming. The available real-time monitoring sensors for fluid properties are generally destructive methods that produce significant and persistent damage to the tubular systems during the installation process. Others use huge and bulky invasive instrument methods that generate considerable pressure reduction and energy loss in tubular systems. For these drawbacks, industries centered their attention on non-invasive and non-destructive testing (NDT) methodologies, which are installed on the outer tubular surface to avoid flow disturbance and desist shutting down systems for installations. Although these sensors showed excellent achievement for monitoring and inspecting pipe health conditions, the performance was not convincing for monitoring the properties of fluids. This review paper presents an overview of the real-time monitoring of fluid properties in tubular systems for industrial applications, particularly for pipe monitoring sensors, viscosity, and flow measurements. Additionally, the different available sensing mechanisms and their advantages, drawbacks, and potentials are discussed.

The main idea of this paper is to assess a simpler and faster procedure leading to the evaluation of the fluid flow rate through a pipe. Currently, several methods are available and they involve ad-hoc instruments. All these methods are characterized by high accuracies and dynamic responses, but they are intended to be inserted within the pipe under investigation, bringing to well-known insertion effects, compromising the reliability of the measurements performed. The authors illustrate a newer methodology for the measurement of flow rates by means of the processing of the vibration signals of pipe walls, inferred by the flow turbulence. Previous studies of the same authors showed a linear dependence between the amplitude of the most prominent peak of the vibration spectra and the flow rate. In this work, the authors relate the power content of the processed signals (by introducing the signal Root Mean Square value) to the flow rate.

Inconsistences regarding flow measurements in real hydraulic circuits have been detected. Intensive studies stated that these errors are mostly associated to flowmeters, and the low accuracy is connected to the perturbations induced by the system layout. In order to verify the source of this problem, and assess the hypotheses drawn by operator experts, a computational fluid dynamics (CFD) model, COMSOL Multiphysics 4.3.b, was used. To validate the results provided by the numerical model, intensive experimental campaigns were developed using ultrasonic Doppler velocimetry (UDV) as calibration, and a pumping station was simulated using as boundary conditions the values measured in situ. After calibrated and validated, a new layout/geometry was proposed in order to mitigate the observed perturbations.

A thermo-anemometric flowmeter design and the principles of its work are presented in the article. A mathematical model of the temperature field in a stream of biofuel is proposed. This model allows one to determine the fuel consumption with high accuracy. Numerical modeling of the heater heat balance in the fuel flow of a thermo-anemometric flowmeter is conducted and the results are analyzed. Methods for increasing the measurement speed and accuracy of a thermo-anemometric flowmeter are proposed.

In the 20th century this distance is still a constraint in efforts to measure and retrieve data. In an efficiency effort, a long distance measuring device is required. One method to measure from a distance is to use the Telemetry method. Telemetry is a method for measuring a variable in which monitoring is done remotely. The use of telemetry can be used to transmit data from the flowmeter sensor to be received by the receiver. This study discusses the effect of obstacles on transmitter work to send data to the receiver and test the accuracy of the flowmeter sensor. From this study it can be concluded that the effective distance of data transmission depends on the obstacle, the farthest distance is the moment without obstacles, then decreases when there is a hitch, and will decrease again when one receiver or transmitter is placed in a closed room. And for the accuracy of the sensor, the percentage of accuracy is low at the time of the slow water current, and vice versa high accuracy is obtained when the water current is fast. Based on the research we poured in this journal, water flow measurements using RF Arduino-based 433MHz Modules can measure the flow of water at a distance of up to 35meter with an average error of only 4.1%.

INTRODUCTION: Ultrasound Transit-Time flowmeters are based on the fact that the time required for an ultrasound pulse to propagate through a given distance in a moving medium is a function of the vectorial sum of pulse propagation velocity and medium velocity. The most common application of this flowmeter in medicine is in the evaluation of blood flow in arteries and veins during heart vascular surgery. The present article describes the design, construction and evaluation of a flow phantom for transit-time flowmeters calibration. METHODS: Basically, it is a hydraulic circuit containing degassed and distilled water. In such a circuit, a constant differential water level is established between two columns that are interconnected by tubes with defined resistance, which determines a known flow rate. A basic theoretical model to estimate the system Reynolds Number and resistance was developed. RESULTS: A flow range between 4.43 ± 0.18 ml.min-1 and 106.88 ± 0.27 ml.min-1 was found to be compatible with physiological values in small vessels. The pressure range was between 0.20 ± 0.03 cmH2O and 12.53 ± 0.07 cmH2O, and the larger Reynolds Number was 1134.07. Experimental and theoretical resistance values were similar. CONCLUSION: A reproducible phantom was designed and built to be assembled with standard low-cost materials and is capable of generating adjustable and continuous flows that can be used to calibrate TTFM systems.

Smart signal acquisition and signal processing methods are necessary for a robust and highly dynamic mass flow measurement on basis of the Coriolis principle, which allows the direct determination of the mass flow independent of process conditions with a precision of 0.2% of reading. Optical sensors which record the movement of the flow pipe have been designed and arranged with focus on fast signal processing and low complexity for a Cramer-Rao optimal information analysis. Therefore it is possible to recognize and compensate superimposed movements of the flow pipe in all six degrees of freedom as well as aging effects of the sensor elements. This leads to an increased zero point stability and a greater flow measurement range. Several algorithms for online phase estimation like Hilbert transform, correlation, discrete-time Fourier transform and quadrature demodulation in combination with minimum phase filters are investigated to develop a system with minimal time delay.

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich., This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively., To obtain a high temporal resolution of mass flow data, a flowmeter based on the differential pressure method has been developed. It is capable of detecting negative flow for investigations of dynamic effects in small centrifugal compressors used for turbocharging automotive internal combustion engines. Experiments were performed at a hot gas test bench focusing on the surge characteristics at different turbocharger speeds and the influence of volume modifications downstream of the compressor. Instantaneous operating points could be traced in the compressor map including the typical orbits at deep surge resulting from the cyclic character of the phenomenon.

The flowmeter is widely used in coal mining because of its higher measurement precision and simple installation without channel project modification. In this paper, a flow measurement method based on velocity-area is investigated, and a functional flowmeter for mining applications with higher precision is designed. The two key parameters, the liquid level and flow velocity are required to be obtained for achieving the proposed method. The proposed flowmeter is composed of three main functional modules: (1) flow velocity detection module based on ultrasonic time difference method, (2) liquid level detection module, and (3) mud level detection module based on ultrasonic pulse echo method. All the measured data are transferred to the monitoring station for analysis and displayed in real-time through M-BUS. The flowmeter is designed focusing on mining applications, and has higher benefits for preventing water disasters in coal mines.

This paper studied a new type of flowmeter, the bypass flowmeter. It is suitable for large-scale pipes. The principle of bypass flowmeter is studied by analyzing flowing in parallel pipes and carrying out experiments at a modified performance test system for centrifugal pumps. The study results showed that the flowrate ratio between the main pipe and the bypass pipe is determined by the geometric structures of pipes and the flowing states in the pipes. The flowrate ratio varies greatly when the Reynolds numbers are relatively lower both in the main pipe and the bypass pipe. The flowrate ratio keeps constant when the Reynolds number in the main pipe is larger than 120000. The head loss becomes smaller when the bypass pipe is connected to the main pipe. The percentage of head loss decrease is from 7.64% to 9.34%. The results indicate that bypass flowmeter is suitable for flowrate measuring in large scale pipes. It will not cause additional head loss to the flow.

Tracer tests often give ambiguous interpretations that may be due to the erroneous location of sampling points and/or the lack of flow rate measurements through the sampler. To obtain more reliable tracer test results, we propose a methodology that optimizes the design and analysis of tracer tests in a cross borehole mode by using vertical borehole flow rate measurements. Experiments using this approach, herein defined as the Bh-flow tracer test, have been performed by implementing three sequential steps: (1) single-hole flowmeter test, (2) cross-hole flowmeter test, and (3) tracer test. At the experimental site, core logging, pumping tests, and static water-level measurements were previously carried out to determine stratigraphy, fracture characteristics, and bulk hydraulic conductivity. Single-hole flowmeter testing makes it possible to detect the presence of vertical flows as well as inflow and outflow zones, whereas cross-hole flowmeter testing detects the presence of connections along sets of flow conduits or discontinuities intercepted by boreholes. Finally, the specific pathways and rates of groundwater flow through selected flowpaths are determined by tracer testing. We conclude that the combined use of single and cross-borehole flowmeter tests is fundamental to the formulation of the tracer test strategy and interpretation of the tracer test results.

International audience; We show how a distributed borehole flowmeter can be created from armored Fiber Optic cables with the Active-Distributed Temperature Sensing (A-DTS) method. The principle is that in a flowing fluid, the difference in temperature between a heated and unheated cable is a function of the fluid velocity. We outline the physical basis of the methodology and report on the deployment of a prototype A-DTS flowmeter in a fractured rock aquifer. With this design, an increase in flow velocity from 0.01 to 0.3 m s21 elicited a 2.5 C cooling effect. It is envisaged that with further development this method will have applications where point measurements of borehole vertical flow do not fully capture combined spatiotemporal dynamics.

The present paper deals with design and realization of a new mass flow sensor using the Peltier effect. The sensor, shaped as a bimetallic circuit includes two continuous parallel strips coated with a great deal of metal plated spots. In such a device, one track performs as a classical thermoelectrical circuitry whose both plated and uncoated parts provide the thermopile junctions. The other strip is subjected to electrical current so as to generate numerous small thermal gradients owing to the Peltier effect. Then, the resulting differences in temperature induce a Seebeck e.m.f. detected by the other strip acting as a receiver. The thermal coupling between transmitter and receiver tracks depends on many variation of the surrounding environment heat transfer coefficient. Therefore, such a device allows us to detect any shift in physical properties related to the apparent thermal conductivity. In special case of a steady state fluid, the induced e.m.f. in the receiving track hinges on the thermal conductivity. When the fluid is in relative motion along the sensor, the velocity can be read out as a funotion of voltage as an application, the sensor is placed into a tube conducting a fluid flow, in order to design a new mass flowmeter.

Ionic polymer–metal composites (IPMCs) are electroactive polymers that can be used both as sensors and actuators. They have been demonstrated for many potential applications, in wet and underwater environments. Applications in fields such as biomimetics, robotics, and aerospace, just to mention a few, have been proposed. In this paper, the sensing nature of IPMCs is used to develop a flowmeter based on the vortex shedding phenomenon. The system is described, and a model is proposed and verified. A setup has been realized, and data have been acquired for many working conditions. The performance of the sensing system has been investigated by using acquired experimental data. Water flux velocities in the range [0.38, 2.83] m s−1 have been investigated. This working range is comparable with ranges claimed for established technologies. Results show the suitability of the proposed system to work as a flowmeter. The proposed transducer is suitable for envisaged post-silicon applications, where the use of IPMCs gives the opportunity to realize a new generating polymeric flowmeter. This has potential applications in fields where properties of IPMCs such as low cost, usability, and disposability are relevant.

This paper illustrates the gas flow rate measurement techniques that can be introduced in future domestic applications. First, the role of the gas meter in legal metrology is introduced. Then, the “intelligent” (or “smart”) gas meter is analyzed, since it should be used in the near future. Such a meter is an improvement of the current domestic diaphragm gas meter, also equipped with electronic components, so as to obtain a more flexible instrument and a more convenient measurement data processing (temperature compensation, remote reading, etc.). After that, static gas meters are analyzed. Such meters have no moving parts. Of this category, only ultrasonic and fluidic oscillator meters are reviewed here. At present they are in an advanced phase of experimentation for custody transfer gas metering. Thanks to their design, which does not include any moving parts, these meters may represent in the future the best solution to measure the consumption of natural gas for domestic use. This paper discusses the operating principles and metrological characteristics of the static meters mentioned above, and provides some experimental results regarding domestic gas measurement. Finally, their possible evolution and application on the international scene are briefly outlined.

After studying the performance and characteristics of actual laminar flowmeters a new disposition for this type of sensors is proposed in such a way that the measurement errors introduced by the intrinsic nature of the device can be minimized. The preliminary study shows that the developing entry region introduces non-linearity effects in all these devices. These effects bring about not only errors, but also a change in the slope of the linear calibration respect of the Poiseuille relation. After a subsequent analysis on how these non-linearity errors can be reduced, a new disposition of this type of flowmeters is introduced. This device makes used of flow elements having pressure taps at three locations along its length and connected to three isolated chambers. In this way, the static pressure can be measured at three locations and contributed to by the pressure taps at the level of each chamber. Thus the linearization error is reduced with an additional advantage of producing a reduced pressure drop. Xunta de Galicia; 07DPI166E Xunta de Galicia; 08TIC035E

BACKGROUND AND OBJECTIVE: Coronary slow-flow phenomenon is characterized by delayed opacification of coronary vessels in a normal coronary angiogram. Although clinical and pathological features have been previously described, the underlying pathophysiology has not been fully elucidated. Thus, it still remains to be determined whether either microvascular or epicardial diffuse atherosclerotic disease is related to slow flow. In this study, we aimed to determine the carotid artery intima-media thickness, which is a marker of atherosclerosis in patients with coronary slow flow, and its possible relationship with the total homocysteine level. METHOD: The study population consisted of 88 patients who underwent coronary angiography because of typical and quasi-typical symptoms of angina. Forty-four patients with angiographically proven coronary slow flow and 44 individuals with normal coronary flow pattern with similar risk profiles were enrolled in the study. Coronary flow patterns of the latter were determined by the thrombolysis in myocardial infarction frame count method. Intima-media thickness was measured by recording ultrasonographic images of both the left and the right common carotid artery with a 12-MHz linear array transducer. Plasma homocysteine, folate and B12 levels were measured from blood samples. RESULTS: Plasma homocysteine levels (μmol/l) and carotid intima-media thickness (mm) of patients with coronary slow flow were found to be significantly higher than that of controls (12.4±4.9 vs. 8.5±2.8, P=0.0001; 0.75±0.08 vs. 0.69±0.06, P=0.0001, respectively). The plasma folate level (ng/ml) was lower in coronary slow-flow patients than in controls (13.8±4.4 vs. 16.5±5.6, P=0.014). The plasma homocysteine level was significantly positively correlated with the mean thrombolysis in myocardial infarction frame count and intima-media thickness of the carotid artery in correlation analysis (r=0.58, P=0.0001; r=0.41, P=0.0001; respectively). CONCLUSION: Homocysteine levels and carotid intima-media thickness increased but folate levels decreased in patients with coronary slow flow. The present findings allow us to conclude that the possible disturbance in the metabolism of homocysteine in patients with coronary slow flow may have a role in the etiopathogenesis of this phenomenon by causing generalized atherosclerosis. © 2006 Lippincott Williams & Wilkins.

A self-compensating fiber optic flow sensor system based on the principle of broadband white-light interferometers and cantilever beam bending is described. The fiber optic sensor system uses two fiber ferrule sensors that are bonded on either side of a cantilever beam to measure the flow rate by monitoring the air-gap changes caused by the bending of the cantilever beam. Cross sensitivity of the temperature and pressure dependence of the sensor can be compensated for automatically. The prototype sensor system was constructed, laboratory characterized, and field tested. The results from the field testing have demonstrated high resolution, repeatability, and stability for on-line detection of the flow rates of fluids. (C) 2004 Optical Society of America. National Petroleum Technology Laboratory U.S. Department of Energy Chevron Texaco Research & Technology Company

The paper deals with today’s existing instruments for measuring the flow of fluid and fuel, their classification is given. The structure and operating principle of a thermoanemometric flowmeter for measuring the biofuel flow was analyzed. A mathematical model of a temperature field in the biofuel flow was developed. It allows accurately determine the flow. The corresponding modeling was carried out. It was found that the volume fuel flow depends on the thermocouple temperature measurement errors in the range of relative errors from 0.01 to 1.0%. For improving the performance of the thermoanemometric flowmeter, a special neuroprocessor that will compensate for random and dynamic measurement errors using artificial neural networks should be included to the computer architecture. The error of measuring the fuel flow will be less than 1% when the measurement error of the heater temperature is 1%. The results can be applied in the design of new highly precise thermoanemometric flowmeters for measuring the biofuel flow.