Nonlinear amplitude control method of Coriolis Mass flowmeter based on A-LADRC

Healthcare is responsible for ~4.4% of global carbon dioxide (CO2) emissions and endoscopy is the third largest contributor. This study aimed to quantify CO2 use in colonoscopy and assess the impact of different valves and practices on emissions and costs. CO2 use was measured using a mass flow meter. The study compared CO2 flow using the standard gas/water valves, which continuously release CO2, with non-leak valves, which only release CO2 when depressed. It also assessed the impact of judicious use of CO2. An unpaired student t test was used to calculate statistical significance. Without a colonoscope attached, CO2 flow averaged 3.24 L/min. With the standard valve, flow dropped to 2.55 L/min, and with the non-leak valve, it was negligible. CO2 emissions were measured intraprocedurally during 351 colonoscopies. Using a non-leak valve and/or judicious CO2 application significantly reduced emissions compared with standard practice using a standard valve. This approach could reduce local emissions by >87%. Nationally, it would lead to emissions reductions of 106.5 metric tons of CO2 per annum with cost savings of >£260 000. Judicious CO2 application and use of a non-leak valve significantly reduced CO2 emissions and costs in colonoscopy, contributing to the UK National Health Service goal of delivering a “net zero” service. We suggest turning off CO2 when not needed, adopting non-leak valves, implementing this practice in other endoscopic procedures, and encouraging all endoscope manufacturers to develop similar valves.

Environmental issues, including global warming, dependence on fossil fuels, deforestation, and rising CO2 emissions, have become major challenges worldwide. In Türkiye, fossil fuel demand has continued to rise over the past two decades, despite policies promoting renewable energy. The effectiveness of these policies on transport-related greenhouse gas (GHG) emissions remains uncertain. To address this gap, this study analyses the long-term evolution of transport emissions over the last 33 years, integrating inventory-based estimates with experimental measurements to provide a metrologically validated dataset. Portable exhaust gas analysers (Horiba PG-350 and Testo 350XL) were used in conjunction with calibrated thermal mass flow meters and thermocouples to quantify CO2, CH4, and N2O emissions across various vehicle types and load conditions. Calibration traceability and uncertainty estimation were performed in accordance with ISO/IEC 17025 and the GUM guidelines. Experimental results were compared with IPCC Tier 2 estimates, showing close agreement for CO2 (± 3.8 %) and larger variability for CH4 and N2O. These findings highlight the essential role of metrology in improving the reliability of emission data and support the integration of measurement-based validation into national GHG inventory frameworks.

UASB reactors arewidely employed in wastewater treatment due totheir operational simplicity and the potential for energy recoveryfrom biogas, although continuous, low-cost monitoring of CH4 and flow rate remains challenging. This work presents the developmentand validation of an IoT system for remote, real-time monitoring,integrating NDIR sensors for CH4/CO2, a temperaturesensor, a pressure sensor, a thermal mass flow meter, and an ESP32platform with web/mobile interfaces. Deployment was carried out ina bench-scale UASB reactor treating an industrial slaughterhouse effluent.Over 30 days of continuous operation, stable data transmission wasrecorded with an average latency of ∼1.77 s; measurements covered42.84–76.16 NL·d–1 (flow) and 53.31–88.0%(CH4), with temperature within a narrow mesophilic range(22.25–27.80 °C) and near-zero sensor drift. Estimatesbased on removed chemical oxygen demand (COD), normalized to STP,yielded 45.18–74.72 NL·d–1 (flow). Temporalagreement with the measured series was observed (MAE = 6.58 NL·d–1 and 4.69 percentage points; MAPE = 9.88% and 6.69%for flow and composition, respectively). This modular, fault-tolerantarchitecture demonstrates feasibility for supporting operational controland assessing the methane energy potential in decentralized applications.

Ambient temperature effects on a densitometer in a multi-sensor mass flowmeter for low liquid fuel flow measurement

We present the first European intercomparison of primary flow measurement standards with hydrogen-enriched natural gas (up to 20% hydrogen in molar fraction) and natural gas with pressure up to 60 bar and volume flow rates in the range (5 to 160) m3/h. We describe the principles of operation of the primary standards and present the transfer standards, a rotary meter and an ultrasonic meter, used for the intercomparison. In many instances, the overlap between the different laboratories is satisfactory, but the collected results are limited and do not allow us to make advanced conclusions. In addition, we investigate the effect of nitrogen impurities (2% in molar fraction) on the performance of low-pressure gas meters for pure hydrogen using newly developed measurement standards. We present the methods and results of this investigation. We show that nitrogen impurities affect the volume flow measurements of an ultrasonic meter but seem to have little effect on a thermal mass flow meter. This paper explores future opportunities and challenges in international intercomparisons involving hydrogen blends and highlights key issues and solutions with hydrogen gas metering in the presence of impurities.

This study presents an eccentric pipe separator (EPS) designed according to the shallow pool principle and Stokes’ law as a compact alternative to conventional gravitational tank separators for offshore platforms. To investigate the internal oil-water flow characteristics and separation performance of the EPS, both field experiments with crude oil on an offshore platform and computational fluid dynamics (CFD) simulations were conducted, guided by dimensional analysis. Crude oil volume fractions were measured using a Coriolis mass flow meter and the fluorescence method. The CFD analysis employed an Eulerian multiphase model coupled with the renormalization group (RNG) k-ε turbulence model, validated against experimental data. Under the operating conditions examined, the separated water contained less than 50 mg/L of oil, while the separated crude oil achieved a purity of 98%, corresponding to a separation efficiency of 97%. The split ratios between the oil and upper outlets were found to strongly influence the phase distribution, velocity field, and pressure distribution within the EPS. Higher split ratios caused crude oil to accumulate in the upper core region and annulus. Maximum separation efficiency occurred when the combined split ratio of the upper and oil outlets matched the inlet oil volume fraction. Excessively high split ratios led to excessive water entrainment in the separated oil, whereas excessively low ratios resulted in excessive oil entrainment in the separated water. Crude oil density and inlet velocity exhibited an inverse relationship with separation efficiency; as these parameters increased, reduced droplet settling diminished optimal efficiency. In contrast, crude oil viscosity showed a positive correlation with the pressure drop between the inlet and oil outlet. Overall, the EPS demonstrates a viable, space-efficient alternative for oil-water separation in offshore oil production.

Dynamic performance analysis of Coriolis mass flowmeter

Measurements of gas flow are crucial in medical applications like respiratory monitoring and mechanical ventilators. Variable area orifice Flow meters (VOFMs) are increasingly recognized for respiratory monitoring, functional assessment, and mechanical ventilation. Area variation of such a flowmeter can be achieved by setting a moving body inserted concentrically and guided through a central rod in the flowmeter, the mechanism that may affect the input-output relationship and produce bias error. Notwithstanding these problems, the VOFM has been advocated to utilize the feature of the membrane’s flexibility as a variable area orifice. Two flowmeter prototypes with flexible membranes the “Medical Flow Sensor FS2 by Hamilton” and the “Datex-Ohmeda Flow Sensor” are tested in this study. The former has a triangular orifice shape, while the latter is circular. A flow test rig is built enabling instantaneous measurements and recording of different air flow rates and differential pressure using a high-sensitivity differential pressure sensor. The experimental results are compared with the outcomes of the solved CFD model, which is solved using the FVM method. Results indicate that for a specified differential pressure (ΔP), the circular orifice sensor “Datex-Ohmeda Flow Sensor” consistently demonstrates a superior mass flow meter relative to the triangular sensor “Medical Flow Sensor FS2 by Hamilton.”

• Performance of Coriolis Flow meter for the use in comparisons. • Typical sources of uncertainty are specified. • A consideration of transfer standard uncertainty led to better comparison evaluations. • Recommendations are provided that aim to improve the robustness of Coriolis meters as transfer standards. For successful comparisons at the highest metrological level, the use of well-performing transfer standards is essential. In fluid flow measurement, Coriolis flow meters have proven to be suitable transfer standards due to their low uncertainty, as demonstrated in several national and international comparisons. This paper summarises the experiences and findings from completed comparisons, and experimental work, and provides practical recommendations for the use of Coriolis meters as transfer standards in future comparisons. Key areas of focus include zero setting, temperature dependencies, pressure effects, meter orientation, and the influence of disturbed inflow conditions as each of these can have a significant impact on meter performance. The paper also presents examples of how these factors are being considered in upcoming key comparisons. The aim is to share recent insights and support best practice in the application of Coriolis meters as transfer standards in high-accuracy flow metrology.

Influence mechanism of temperature-induced zero drift on cryogenic Coriolis flow meters

Flow pattern recognition model based on deep neural networks using only an in-service dual-frequency Coriolis flowmeter

For more than five decades, vibrating tube resonators have evolved from fragile laboratory devices into versatile platforms used in industrial metrology, biomedical research, and education. This technology originated with glass U-tube densitometers, which established the foundation for resonance-based density measurements. Later, metallic tubes extended operation to harsh conditions, including high pressure, elevated temperature, and cryogenic environments, enabling applications ranging from supercritical fluid studies to aerospace propulsion. The vibrating tube principle also inspired Coriolis flowmeters, which can monitor both density and mass flow. Miniaturization through microelectromechanical systems (MEMS) has led to microchannel resonators that can weigh biomolecules, nanoparticles, and cells with high sensitivity. Subsequent innovations improved readout using piezoresistive and piezoelectric schemes, increased throughput with array architectures, and integrated heaters for thermal property measurements. More recent advances include integrating capacitive electrodes, enabling access to electrical and dielectric properties of liquids. Meanwhile, renewed interest in glass and metallic tube resonators has highlighted their robustness, scalability, and utility for handling larger biological entities and for educational purposes. Macro- and micro-scale approaches complement each other, ensuring continuity across scales and pointing toward future integration with optical, magnetic, and quantum modalities.

A compressible flow experiment was developed to demonstrate engineering fundamentals and allow students to perform meaningful calculations on student-collected experimental data. Student teams employed four methods to determine the mass flow rate of air flowing into an initially evacuated tank under choked flow conditions. The four methods were (1) theoretical calculation of mass flow through a sonic nozzle, (2) direct measurement with the mass flow meter, (3) the mass point method (e.g., the difference in calculated initial and final masses inside the tank), and (4) the mass slope method (e.g., calculating the mass inside the tank via pressure and temperature data at each time step). These methods are presented along with their measurement uncertainty calculations. Example results demonstrated mass flow rate measurements and overlapping uncertainty bands using choked flow through a 0.096-inch diameter critical flow venturi resulting in flow rates of 1.051 ± 0.012 g/s, 1.045 ± 0.066 g/s, 1.030 ± 0.010 g/s, and 1.042 ± 0.005 g/s for Methods 1–4, respectively. The different methods allow instructors to have flexibility in varying the activity between student cohorts. The experiment demonstrated fundamentals of ideal gas behavior, choked flow, and polytropic compression processes. The experiment gave student teams the opportunity to conduct an experiment, utilize common measurement instruments, and apply classroom theory and concepts to solve a relevant engineering problem: quantifying the flow rate of a compressible gas. The associated Accreditation Board for Engineering and Technology (ABET) outcomes, applicable engineering standards, and general safety issues are discussed.

Electrochemical hydrogen compression (EHC) is a progressive technology for end of pipe hydrogen compression and purification in one step. EHC is based on electrochemical hydrogen pump, where inlet hydrogen is oxidised on the anode to protons under deliberation of electrons, protons are transported to cathode, where, they are combined with electrons transported through external electrical circuit and hydrogen is formed at desired pressure. In contrast with state-of-the-art (mechanical) hydrogen compressors, EHC operates at moderate temperatures and contains no moving parts, improving the safety and energy efficiency due to the reduced entropic component of the compression process.EHC device utilises zero gap membrane-electrode assembly with electrodes separated by proton-exchange membrane (PEM). Anode gas-diffusion layer has to be made of rigid porous material able to mechanically support the membrane. Cathode gas-diffusion layer is made of carbon-based porous materials. Nanoparticulate Pt catalyst bonded with proton-conductive ionomer is localised between gas-diffusion layers and the membrane. This arrangement ensures facilitation of a three-phase boundary between Pt (connected to electron conductor), ionic conductor and hydrogen gas. State-of-the-art materials of membrane and ionomer are based on perfluorinated sulfonated polymers (PFSAs). While attaining an excellent chemical stability and conductivity, its production faces significant legislative and environmental challenges especially in EU. The possible solution is to use hydrocarbon-based membranes and ionomers. Given that electrode potentials around 0 V vs RHE and moderate operating temperatures are used in EHC cell, the stability of hydrocarbon PEMs should be sufficient, creating an interesting area of their application.One of the major issues of EHC process is its overall efficiency. This comprises two main components, the Faradaic efficiency and the Voltaic efficiency. The former is lowered by hydrogen crossover through the membrane and can be minimised by increasing the membrane thickness. The latter is impacted by cell Ohmic resistance of which membrane resistance represents the main contribution. Last but not least, mechanical stability of membrane under asymmetric cell pressures is essential for EHC durability. Due to these contradicting requirements of EHC technology on the membranes, hydrocarbon-based material has to be selected carefully.The goal of this study was to characterise experimental hydrocarbon membranes in terms of swelling and proton conductivity, compare them to commercial PFSA PEMs and test their properties in EHC single cell. Dimensional and weight changes due to membrane activation were observed with following determination of proton conductivity in flow cell, utilising both the liquid water and the humidified nitrogen as circulating media.Commercial membranes of Nafion product family (117, 212, 211, HP, XL) exhibited good proton conductivity under water and humidified nitrogen flows across temperature range of 30 to 90 °C. Fabrication method and presence of reinforcement had high impact on membrane properties. Membranes prepared by extrusion (Nafion 117, 212) tend to swell more than casted (Nafion 211). Reinforcement (Nafion HP, XL) has negative impact on membrane conductivity but, on the other hand, improves membrane dimensional and mechanical stability. Experimental hydrocarbon membranes based on chloromethylated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene [1] functionalised with sulfonic groups exhibited reasonable dimensional stability and conductivity, but, in comparison with commercial PFSA PEMs, its properties were inferior.Membrane-electrode assemblies for EHC single cell consisted of catalyst-coated anode based on sintered titanium, membrane and catalyst-coated cathode based on carbon paper with microporous layer. Single cell was operated at ambient temperature with fully humidified hydrogen inlet and constant pressure (2 bar) of anode compartment and pressure of cathode compartment varying within the range of 3 to 30 bar. Stationary polarisation curves and electrochemical impedance spectra were recorded at various current densities and cathode compartment pressures. Overflows of hydrogen from backpressure valves on the anode and cathode side were recorded by mass flow meters and, together with electrochemical data, were used for calculation of Faradaic and Voltaic efficiencies, as well as for determination of hydrogen crossover through the studied membrane.Experiments performed confirmed the importance of balance between hydrogen crossover and electrical resistance of membrane. Experimental hydrocarbon membranes performed well in terms of hydrogen crossover, but their performance was limited by comparatively lower proton conductivity. In summary, these results support the applicability of hydrocarbon-based membrane in EHC cell. In the next stage, catalyst layer with hydrocarbon ionomer will be optimised and integrated into cell with hydrocarbon membrane.[1] 10.1016/j.eurpolymj.2019.109381Project TS01030039/Advanced Hydrogen Compression Technology - Electrochemical Compression is co-financed with state support of Technology Agency of the Czech Republic within the framework of program THETA 2. This work was supported by the project "The Energy Conversion and Storage", funded as project No. CZ.02.01.01/00/22_008/0004617 by Programme Johannes Amos Comenius, call Excellent Research.

Abstract Pipes for heat exchangers are widely utilized in various thermal systems, with notable applications in the building industry, such as underfloor heating and heat pump systems. To reduce manufacturing costs, these components are often fabricated from polymeric materials, which offer favorable mechanical properties and high corrosion resistance. However, their relatively low thermal conductivity can limit overall heat transfer efficiency. This study presents the design and implementation of an experimental setup for the comparative evaluation of convective heat transfer in polymeric pipes. The setup employs a tube-in-tube configuration, with 2-meter-long pipe samples mounted within a purpose-built assembly. The pipe under investigation serves as the inner tube, with water-glycol mixtures flowing on both the inner and outer sides to facilitate controlled heat transfer. Depending on the selected operating mode, heat can be transferred either into or out of the tested pipe. Temperature regulation of both fluid streams is achieved using two immersion circulation baths, while a 5.5 kW chiller is employed to maintain the temperature of the cold stream. A variable speed pump and a control valve ensure precise flow control within the test sample. The mass flow rate is measured accurately using a Coriolis flow meter. Inlet and outlet temperatures for both streams are monitored with Class A PT100 sensors, and pressure drop across the pipe sample is recorded using a piezoelectric differential pressure transmitter. A dedicated LabVIEW application enables real-time data acquisition and system monitoring. Initial system verification and testing were performed using three commercially available pipes for heat exchangers, i.e., two PEX pipes with outer diameters of 32 and 40 mm, designed for underfloor heating and ground heat exchanger applications, respectively, and a multilayer PE-RT pipe with a 32 mm outer diameter, also intended for underfloor heating systems.

The convergence of Industrial Internet of Things (IIoT) and digital twin technology offers new paradigms for process automation and control. This paper presents an integrated IIoT and digital twin framework for intelligent control of a gas–liquid separation unit with interacting flow, pressure, and differential pressure loops. A comprehensive dynamic model of the three-loop separator process is developed, linearized, and validated. Classical stability analyses using the Routh–Hurwitz criterion and Nyquist plots are employed to ensure stability of the control system. Decentralized multi-loop proportional–integral–derivative (PID) controllers are designed and optimized using the Integral Absolute Error (IAE) performance index. A digital twin of the separator is implemented to run in parallel with the physical process, synchronized via a Kalman filter to real-time sensor data for state estimation and anomaly detection. The digital twin also incorporates structured singular value (μ) analysis to assess robust stability under model uncertainties. The system architecture is realized with low-cost hardware (Arduino Mega 2560, MicroMotion Coriolis flowmeter, pneumatic control valves, DAC104S085 digital-to-analog converter, and ENC28J60 Ethernet module) and software tools (Proteus VSM 8.4 for simulation, VB.Net 2022 version based human–machine interface, and ML.Net 2022 version for predictive analytics). Experimental results demonstrate improved control performance with reduced overshoot and faster settling times, confirming the effectiveness of the IIoT–digital twin integration in handling loop interactions and disturbances. The discussion includes a comparative analysis with conventional control and outlines how advanced strategies such as model predictive control (MPC) can further augment the proposed approach. This work provides a practical pathway for applying IIoT and digital twins to industrial process control, with implications for enhanced autonomy, reliability, and efficiency in oil and gas operations.

The paper addresses the challenges associated with applying machine learning models to detect outliers in metrological datasets. While such models ensure the possibility to identify complex deviations in the structure of a sample without relying on prior statistical assumptions, they do not provide normatively justified criteria for assessing the reliability of their decisions. Specifically, such models lack interpretable confidence indicators, metrological traceability, and formalised thresholds to determine whether an outlier is genuine. One proposed solution involves assessing the impact of eliminated anomalous values detected by the Isolation Forest model on the standard measurement uncertainty of Type A when the initial sample size is preserved through repeated measurements. This approach was validated using real-life measurements of liquid flow performed with Coriolis flowmeters of various diameters. The results empirically proved the effectiveness of the method in cases where the elimination of distortion-inducing values led to a significant reduction in measurement variability. However, several limitations were also identified, including the sensitivity of models to small sample sizes, the impracticality of performing repeated measurements in many real-life scenarios, and the lack of an objective threshold to determine the “significance” of uncertainty reduction. These findings highlight the need for further study of the formalization of confidence criteria in anomaly detection within the metrological domain, particularly in the context of compliance with international standards such as ISO/IEC 17025. Despite these limitations, the application of machine learning models opens new opportunities for automating the analysis of metrological data and highlights the need to develop harmonized approaches for integrating such solutions into the regulatory framework.

In the course of this project, real time oil leakage detection without false alarm has been designed and implemented to ensure that leakages are detected without any incidence of false alarm. Here, a mass flow rate difference between the two ends of the oil pipeline is used as the basis of the oil leakage detection. A pipeline that connects two flow stations A and B is used as a reference. Flow station A has a microcontroller as the central control unit with pressure pump and sound alarm as the output devices and mass flow meter and start button as the input devices. It also has a mobile phone that serves on as a modem. Equally flow station B has similar arrangement as the flow station A except that it has sound alarm as the output device. This project is based on the modification of continuity equation (Inlet Mass flow rate equals outlet Mass flow rate) to Inlet Mass flow rate equals Outlet mass flow rate plus Losses due to pipeline. At interval of time (t), the flow meter at flow station A measures the mass flow rate MA and sends its value to flow station B via the mobile phone that acts as the modem. Flow station B in return measures its mass flow rate MB and compares it with MA received flow station A. If the difference between MA and MB is less than or equal to the threshold acceptable loss for the given pipeline, the system continues to pump oil through the pipeline but if the difference becomes greater than the threshold loss of the pipeline, it means that leakage has occurred. Hence, flow station B sends short message service (SMS) to flow station A to alert it that leakage has occurred and equally alerts its workers using sound alarm. Once, flow station A receives a short message service (SMS) alert from flow station B that leakage has occurred, it stops the pump and alerts its workers of the leakage. This system is real time based and eliminates false alarm that is common with other methods of leakage detection based on flow rates, since the exact tolerable threshold loss ML due to the pipeline length, cross sectional area and density of fluid flowing through the pipeline over a given time was considered as the acceptable difference between mass flow rates at the inlet and outlet of the pipeline.

The results of a calibration round performed on Coriolis mass flowmeters, originally calibrated with water at factory conditions and recalibrated with different fluids at several flow calibration facilities, are discussed in this paper. These calibrations were dedicated to proving the transferability concept from water to other fluids, some of which are relevant to energy transition. The obtained results confirmed the robustness of the tested instruments’ performance and the viability of using the transferability approach as a reliable alternative.