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This paper describes the application of multiwavelength photoplethysmography (MW-PPG) in reflectance mode for noninvasive measurements of total hemoglobin concentration. Consumer wrist-wearable devices (smartwatches, wristbands) typically contain a photoplethysmography sensor operating in reflectance mode, as opposed to clinical pulse-oximetry sensors operating in transmittance mode. We assume that the generally accepted approach to the analysis of the transmittance-mode MW-PPG signal, based on the direct implementation of the Beer-Lambert law, is not applicable to the analysis of reflectance-mode MW-PPG signals. We propose that the shape of the MW-PPG signal carries information regarding the distribution of optical paths at different wavelengths within the tissue, which is crucial for the correct estimation of the absorption of light in the probe volume. We have developed and tested several machine-learning algorithms to analyze the reflectance-mode MW-PPG signal and to estimate the total hemoglobin concentration based on this analysis. To train and validate the algorithms, we collected a dataset of 840 MW-PPG signals measured from 170 volunteers by using a wrist-wearable PPG sensor. Three reference devices were used to label the data and test the performance of the developed algorithms: an invasive laboratory blood test, minimally invasive HemoCue Hb 201+, and noninvasive Masimo Radical-7 transmittance mode pulse-oximeter. The best performance achieved with the developed algorithm, mean absolute error MAE $\approx 12.6\pm $ 1.7 g/L and correlation coefficient R $\approx 0.66\pm $ 0.09, is comparable with the performance of the clinical noninvasive device.

Studies of contaminants obtained by spraying ITER-grade Be on a quasi-stationary plasma gun facility QSPA-Be are presented. Contaminating films, consisting mainly of Be and O in approximately equal proportions, were deposited on substrates of quartz, sapphire, single crystalline silicon (SC-Si) and NaCl crystal. Characterization of the deposits was performed using SEM, XPS, EBS, AFM, SE, TEM&SAED and micro-interferometry showing polycrystalline BeO films similar as found in JET-ILW. Films on SC-Si and NaCl were used to characterize their composition and morphology. The cleaning rates in the 81.36 MHz RF discharges in He or D2 at 2 Pa were measured on the SC-Si target. The measured etching rate of the deposited films was several times higher than the rate calculated from the theoretical value of beryllium oxide sputtering yield. Test cleaning of these contaminants was carried out in a capacitively coupled RF discharge (CCRF) from the surface of sapphire and quartz plates, which were considered as a mock-ups of the protective window of the first mirror unit (FMU) designed for ITER divertor Thomson scattering diagnostic system (DTS).

Тhe archaeological complex in Kosharna is located at 3 km to the southwest of the eponymous village in the areas Kajnanak dere and Koru Gjoldjuk. It consists of 2 tell-settlements and adjoining cemetery dated to the second half of Chalcolithic period. A clay feature was found within a hoard of ceramic vessels in the Chalcolithic cemetery. The situation was interpreted by the excavator and current author as a ceramic structure – depot for ceramic vessels, which have been used during the burial ceremonies. The hoard is related to the Late Copper Age and the Gumelnitsa culture. The current paper is a response to the article by Stilyan Ivanov offering reinterpretation of the feature with the hoard as a kiln for single firing of ceramics. The analysis focuses on four field observations and conclusions – the location, secondary burning, the presence of the vessels and the remains of a clay structure. The discovered feature is still without analogue in Balkan prehistory.

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We developed compact, robust and accurate particulate matter (PM) sensor that allows remote detection of particles in open air under straight ambient light (>10 kLux) and arbitrary wind (speed and direction). The sensor operates as a particle counter and employs interferometric detection of the coherent light scattered by moving particles. Performance of the developed sensor was evaluated both in open air under typical indoor conditions and under controllable conditions inside environmental chamber with the standard test particles (size range: $0.5 ~\mu \text{m}$ – $6 ~\mu \text{m}$ , concentrations: $0 ~\mu \text{g}$ /m3 – $1000 ~\mu \text{g}$ /m3, airflow: 10 cm/s – 0.4 m/s) in comparison with the laboratory grade reference equipment. We confirmed experimentally ± $10 ~\mu \text{g}$ /m3 accuracy within 0 – $1000 ~\mu \text{g}$ /m3 detection range for PM2.5 particles. To our knowledge, the sensor has smallest footprint among available dust sensors and is suitable for surface mount packaging in a waterproof case. The sensor does not require maintenance, has high accuracy and low power consumption. Due to very compact optical design (3 mm $\times6$ mm $\times3$ mm), possible applications include wearable devices (smartphones, smartwatches), smart home things (smart speakers, hubs, weather stations), robotics (vacuum cleaners, home assistants), and other consumer devices. [ABSTRACT FROM AUTHOR]

Transport and redeposition of plasma-facing materials in future fusion devices may have a critical influence on performance of in-vessel components. Evaluation of the impurity migration in diagnostic ports is important to predict degradation of in-vessel optics during the main plasma discharges as well as for development of in-situ cleaning maintenance. The Monte-Carlo code KITe was developed for modeling transport of neutral particles in weakly ionized plasma. The code employs advanced neutral particle collision model. The first KITe simulation and experimental validation of sputtered atom transport demonstrate performance of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper describes the challenges of Thomson Scattering implementation in the ITER divertor and evaluates the capability to satisfy project requirements related to the range of the measured electron temperature and density. A number of aspects of data interpretation are also discussed. Although this assessment and the proposed solutions are considered in terms of ITER compatibility, they may also be of some use in currently operating magnetic confinement devices. [ABSTRACT FROM AUTHOR]

Recent research at three small tokamaks with different parameters located at the Ioffe Institute—the spherical tokamak Globus-M, the large aspect ratio tokamak FT-2 and the compact tokamak TUMAN-3M—are reviewed. This overview covers energy confinement (Globus-M and FT-2), L–H transition (TUMAN-3M and FT-2), Alfvén waves (Globus-M and TUMAN-3M), ion cyclotron emission (TUMAN-3M), major plasma discharge disruption (Globus-M) and scrape-off layer (Globus-M) studies. A full-f global gyrokinetic modeling benchmark using synthetic diagnostics in FT-2 is described. Anomalous absorption and emission in electron cyclotron resonance heating experiments due to the parametric excitation of localized upper hybrid waves are analyzed theoretically. Progress in the development of the neutral particle analysis, gamma-ray spectrometry and divertor Thomson scattering combined with laser-induced fluorescence diagnostics for ITER is discussed. The status of the new Globus-M2 spherical tokamak is reported. [ABSTRACT FROM AUTHOR]

Tritium retention inside the vacuum vessel is a potentially serious constraint in the operation of large-scale fusion machines like ITER. An in situ diagnostics for first wall H/D/T retention by laser induced desorption spectroscopy (LIDS) is proposed for use between plasma discharges. The technique is based on local baking of the first wall by laser irradiation and subsequent analysis of the in-vessel gas by optical emission spectroscopy of plasma radiation. The local heating implementation, kinetics of H/D/T thermal extraction and the accuracy of optical emission spectroscopy measurements are analysed. To resolve the H/D/T lines spectroscopically, their thermal broadening should be minimized to prevent overlapping of the line shapes. A comparative performance analysis of several types of plasma sources with relatively cold ions is made including the following types of discharges: Penning, RF multipactor, laser torch and ECR. All these radiation sources require rather low power and could be used for remote in situ measurements of relative densities of the thermally extracted hydrogen isotopes. [ABSTRACT FROM AUTHOR]