SUPPLEMENTARY TOOLS TO MEASURE AND UNDERSTAND THE FLOW IN THE CONTINUOUS CASTING MOULD

For the production of clean steel it is important to control the flow in the mould. A lot of modelling workhas already been done to study the flow behaviour in the mould. Measurements in the continuous castingmould are necessary to validate the modelling work, especially when multiphase flow is studied or whenelectromagnetic flow control systems are incorporated. For a few years, two measuring principles have beenused to study the flow behaviour at the meniscus in the mould at Corus IJmuiden No.2 BOS. The mainmethod is a simple flow measuring device, which consists of a refractory tube sealed at the bottom and fixedat a pivoting point at the top. The tube is submerged in the liquid steel in the mould. Measuring the resultinginclination angle reveals the flow direction and gives a measure of the velocity. In this way the effect of castingparameters on flow behaviour can be studied, such as the effect of the submersion depth of the SEN, the Arflowon the shrouding system (between the tundish and mould) and the change from double roll to single rollflow in the mould. Also, measurements are done with the ‘nail board’ method giving a snapshot of the flowdirection at multiple locations in the meniscus. An electromagnetic sensor was used to measure the multiphaseflow condition in the SEN. In this paper results of these measurements are shown and examples are comparedwith CFD calculations. A better understanding of the effect of casting parameters on the flow pattern in themould was obtained using these supplementary tools

Dynamic Light Scattering: A New Noninvasive Technology for Neonatal Heart Rate Monitoring

Background: Heart rate (HR) detection in premature infants using electrocardiography (ECG) is challenging due to a low signal amplitude and the fragility of the premature skin. Recently, the dynamic light scattering (DLS) technique has been miniaturized, allowing noninvasive HR measurements with a single sensor. Objective: The aim was to determine the accuracy of DLS for HR measurement in infants, compared to ECG-derived HR. Methods: Stable infants with a gestational age of ≥26 weeks, monitored with ECG, were eligible for inclusion. HR was measured with the DLS sensor at 5 different sites for 15 min each. We recorded every 10th second of the DLS-derived HR and the DLS signal-to-noise ratio (SNR), and the ECG-derived HR was extracted for analysis. Patients were randomly divided into 2 groups. In the first group, the optimal SNR cut-off value was determined and then applied to the second group to assess agreement. Results: HR measurements from 31 infants were analyzed. ECG-DLS paired data points were collected at the forehead, an upper extremity, the thorax, a lower extremity, and the abdomen. When applying the international accuracy standard for HR detection, DLS accuracy in the first group (n = 15) was optimal at the forehead (SNR cut-off 1.66). Application of this cut-off to the second group (n = 16) showed good agreement between DLS-derived HR and ECG-derived HR (bias -0.73 bpm; 95% limits of agreement -15.46 and 14.00 bpm) at the forehead with approximately 80% (i.e., 1,066/1,310) of all data pairs remaining. Conclusion: The investigated DLS sensor was sensitive to movement, overall providing less accurate HR measurements than ECG and pulse oximetry. In this study population, specific measurement sites provided excellent signal quality and good agreement with ECG-derived HR

Novel transcutaneous sensor combining optical tcPO2 and electrochemical tcPCO2 monitoring with reflectance pulse oximetry

This study investigated the accuracy, drift, and clinical usefulness of a new optical transcutaneous oxygen tension (tcPO2) measuring technique, combined with a conventional electrochemical transcutaneous carbon dioxide (tcPCO2) measurement and reflectance pulse oximetry in the novel transcutaneous OxiVenT™ Sensor. In vitro gas studies were performed to measure accuracy and drift of tcPO2 and tcPCO2. Clinical usefulness for tcPO2 and tcPCO2 monitoring was assessed in neonates. In healthy adult volunteers, measured oxygen saturation values (SpO2) were compared with arterially sampled oxygen saturation values (SaO2) during controlled hypoxemia. In vitro correlation and agreement with gas mixtures of tcPO2 (r = 0.999, bias 3.0 mm Hg, limits of agreement − 6.6 to 4.9 mm Hg) and tcPCO2 (r = 0.999, bias 0.8 mm Hg, limits of agreement − 0.7 to 2.2 mm Hg) were excellent. In vitro drift was negligible for tcPO2 (0.30 (0.63 SD) mm Hg/24 h) and highly acceptable for tcPCO2 (− 2.53 (1.04 SD) mm Hg/12 h). Clinical use in neonates showed good usability and feasibility. SpO2-SaO2 correlation (r = 0.979) and agreement (bias 0.13%, limits of agreement − 3.95 to 4.21%) in healthy adult volunteers were excellent. The investigated combined tcPO2, tcPCO2, and SpO2 sensor with a new oxygen fluorescence quenching technique is clinically usable and provides good overall accuracy and negligible tcPO2 drift. Accurate and low-drift tcPO2 monitoring offers improved measurement validity for long-term monitoring of blood and tissue oxygenation. [Figure not available: see fulltext.]