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• A novel method for holdup measurement of three phases is proposed. • The holdup error for all three phases remains within 1% • An ultrasonic flexible substrate device was used for fluid hold up measurements. • Specific attenuation coefficient was introduced to distinguish oil and water phases. The precise measurement of multiphase flow holds significant importance across diverse industrial contexts. However, rigid probes struggle with the variable dimensions of curved surfaces, while flexible probes are hindered by fragility, susceptibility, and challenges in large-scale production. Herein, we propose an ultrasonic device featuring a flexible substrate that seamlessly amalgamates flexibility and rigidity to enable precise measurement of three-phase flow. Through simulation, we determine the optimal ultrasonic frequency (1 MHz) and flexible substrate thickness (3 mm) for a specified probe and pipe size (20 mm). A novel concept, the specific attenuation coefficient (SAC), derived from the voltage-amplitude of transmitted and received signals and propagation distance, is introduced to differentiate between oil and water. The discrepancy between measured and actual three-phase holdups are 0.55 %, 0.36 %, and 0.59 % for water, gas and oil, respectively, with a variance of measurement results 0.027. [ABSTRACT FROM AUTHOR]

Purpose: The combined effects of grain digestibility and dietary fibre on digesta passage rate and satiety in humans are poorly understood. Satiety can be increased through gastric distention, reduced gastric emptying rate and when partially digested nutrients reach the terminal ileum to stimulate peptide release through the ileal/colonic brakes to slow the rate of digesta passage. This study determined the effects of grain digestibility and insoluble fibre on mean retention time (MRT) of digesta from mouth-to-ileum, feed intake (FI), starch digestion to the terminal ileum and faecal short chain fatty acids (SCFA) in a pig model. Method: Twelve grain-based [milled sorghum (MS), steam-flaked-sorghum, milled wheat, and steam-flaked-wheat (SFW)] diets with different intrinsic rates of starch digestion, assessed by apparent amylase diffusion coefficient (ADC), and fibre from oat hulls (OH) at 0, 5 and 20% of the diet were fed to ileal-cannulated pigs. Result: MRT was affected by grain-type/processing (P < 0.05) and fibre amount (P < 0.05). An approximate tenfold increase in ADC showed a limited decline in MRT (P = 0.18). OH at 20% increased MRT (P < 0.05) and reduced FI (P < 0.05). Ileal digestibility of starch increased and faecal SCFA concentration decreased with ADC; values for MS being lower (P < 0.001) and higher (P < 0.05), respectively, than for SFW. Conclusions: Lower ileal digestibility of starch, higher faecal SCFA concentration and longer MRT of MS than SFW, suggest the ileal/colonic brakes may be operating. FI appeared to decrease with increasing MRT. MRT increased and intake decreased with grain-based foods/feeds that have low starch digestibility and substantial amounts of insoluble fibre. [ABSTRACT FROM AUTHOR]

Most ultrasonic flowmeters utilize several wedge sensors for transmission and reception. Thus, the location and alignment of the sensors are critical factors that determine the performance of the ultrasonic flowmeter. In this study, we proposed an ultrasound liquid flowmeter utilizing a 128-element linear array transducer with a transmit delay control for varying the incidence angles of ultrasound wave transmission. The performance of the flowmeter was evaluated at flow rates of 0–50 L/min in a specially designed pipe system. Flow estimation was performed with the transit-time method using cross-correlation with phase zero-crossing for sub-sample estimation. While a single plane wave approach performed invasive electromagnetic measurements with only 74% accuracy as a reference, a multiple angular compensation method with 24 angles was proposed to increase the accuracy of measurements up to 93%. This study demonstrated the capability of the non-invasive single-sided ultrasonic flowmeter with a linear array transducer for liquid flow measurements in the metal pipe system. [ABSTRACT FROM AUTHOR]

This paper describes a highly accurate airflow volumetric flowmeter using piezoelectric micromachined ultrasonic transducers (pMUTs) arrays based on transit time. Two pieces of 10by10 multipled aluminum nitride (AlN) pMUTs arrays at resonant frequency of 980 kHz are employed to transmit and receive ultrasonic signals alternately. The dimension of the fabricated 10by10 array is about $3.5 \times 3.5$ mm2, so the pMUTs-based flowmeter is able to measure flow rate in a 3D-printed pipe with an inner diameter of 10 mm. An evaluation board TDC1000-TDC7200EVM with resolution in ns is used to excite the transducers and handle the received signal. Leveraging on the high signal to noise ratio (SNR, ~29dB) of the pMUTs array and excellent resolution (ns) of the evaluation board, the flowmeter has high accuracy. For the reference volumetric flow rate varying from 0–9 L/min in the range of laminar flow, the relative errors of the correctional volumetric flow are within 3%. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The low-impedance transit-time oscillator (LITTO) without foils is a new high-power microwave generator. Its main operation mode is the coaxial transverse mode \TM01. This paper solves the field distributions and the corresponding beam coupling coefficients in the LITTO. As shown in this paper, the modulating electric field in the multicavity LITTO can be derived from a single-cavity theory; thus, its corresponding beam coupling coefficient can be easily obtained. [ABSTRACT FROM PUBLISHER]

Abstract: Objective: Transit-time flow measurement is widely accepted as an intra-operative assessment in coronary artery bypass grafting (CABG). However, the two most commonly applied flowmeters, manufactured by MediStim ASA and Transonic Inc., have different default filter settings of 20 and 10Hz, respectively. This may cause different flow measurements, which will influence the reported results. The aim was to compare pulsatility index (PI) values recorded by the MediStim and Transonic flowmeters in two different clinical settings: (1) analysis of the flow patterns recorded simultaneously by both flowmeters in the same CABGs; and (2) evaluation of flow patterns under different levels of filter settings in the same grafts. Methods: Graft flow and PI were measured using the two different flowmeters simultaneously in 19 bypass grafts. Finally, eight grafts were assessed under different digital filter settings at 5, 10, 20, 30, 50 and 100Hz. Results: The Transonic flowmeter provided substantially lower PI as compared with the MediStim flowmeter. By increasing the filter setting in the flowmeter, PI increased considerably. Conclusions: The MediStim flowmeter displayed a lower PI than the Transonic, due to a lower filter setting. In the Transonic, flow signals are filtered at a lower level, rendering a ‘smoother’ pattern of flow curves. Because different filter settings determine different PIs, caution must be taken when flow values and flowmeters are compared. The type of flowmeter should be indicated whenever graft flow measurements and derived indexes are provided. [Copyright &y& Elsevier]

The theoretical analysis of microwave characteristics of the n+p+νn+ TUNNETT diodes made of silicon carbide is carried out. The expressions for the impedance and its active and reactive components as well as expressions for the frequency range, where the negative differential resistance takes place, and the maximal frequency of oscillations are obtained for the TUNNETT diodes made of SiC. After numerical calculations, the conclusion is made that the performance potential of TUNNETTs is better than that of the other transit time devices in very high frequency range. The use of silicon carbide for the manufacture of TUNNETTs can promise better microwave parameters over the range of frequencies 100–500 GHz. [Copyright &y& Elsevier]