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Abstract: This dataset was prepared in the context of the HybridNeuro project (https://www.hybridneuro.feri.um.si/). It contains a collection of simultaneous EMG and EEG recordings from 7 healthy volunteers. The main purpose of data collection was to investigate the role of beta-band oscillations in motor control by examining how cortical beta activity propagates to the motor unit pool and can be measured at the peripheral level using high-density EMG. Surface EMG was recorded using 64-channel electrode grids arranged in a 13 × 5 configuration with one missing corner electrode and an interelectrode distance of 4 mm (OT Bioelettronica, Torino, Italy). Signals were amplified (150 V/V), sampled at 2048 Hz using a Quattrocento system (OT Bioelettronica, Torino, Italy), and band-pass filtered between 20 and 500 Hz. Different grid placements were employed to maximize the number of motor units decomposed from the EMG signals. EEG signals were recorded with 31 active gel-based electrodes positioned according to the International 10–20 system, with FCz as the reference electrode (actiCAP, Brain Products GmbH, Gilching, Germany). Signals were amplified and sampled at 1 kHz using a BrainVision actiCHamp Plus system (Brain Products GmbH, Gilching, Germany). EEG, EMG, and the exerted force signals were temporally synchronized using a common digital trigger sent to both recording systems. Participants performed 2 repetitions of 4 sets of trapezoidal submaximal isometric contractions using the right tibialis anterior muscle, at 4 different contraction levels. Total task length was 640 s (not including rests). Each task's data is stored in a separate file in Matlab format (.MAT). Total dataset size is 8.5 GB.
Keywords: surface high density electromyogram (HDEMG), electroencephalogram (EEG), dataset, tibialis anterior, isometric ankle dorsiflexion, beta-band oscillations, motor control, HybridNeuro
Published in DKUM: 06.01.2026; Views: 0; Downloads: 6
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Abstract: In this work, Laser Powder Bed Fusion (LPBF), an additive manufacturing (AM) process, was optimised to produce pure magnesium components. The focus of the presented work is on the prediction of the relative product density using the machine learning model XGBoost to improve the production process and thus the usability of the material for practical use. Experimental tests with different parameters, laser power, scanning speed and layer thickness, and fixed parameters, track overlapping and hatching distance, were analysed and resulted in relative material densities between 89.29% and 99.975%. The XGBoost model showed high predictive power, achieving an R2 test result of 0.835, a mean absolute error (MAE) of 0.728 and a root mean square error (RMSE) of 0.982. Feature importance analysis showed that the interaction of laser power and scanning speed had the largest influence on the predictions at 35.9%, followed by laser power × layer thickness at 29.0%. The individual contributions were laser power (11.8%), scanning speed (10.7%), scanning speed × layer thickness (9.0%) and layer thickness (3.6%). These results provide a data-based method for LPBF parameter settings that improve manufacturing efficiency and component performance in the aerospace, automotive and biomedical industries and identify optimal parameter regions for a high density, serving as a pre-optimisation stage.
Keywords: additive manufacturing, machine learning, XG Boost, magnesium, relative density
Published in DKUM: 03.11.2025; Views: 0; Downloads: 6
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Abstract: In this study, the extraction efficiency of natural deep eutectic solvents (NADES) based on choline chloride as a hydrogen bond acceptor (HBA) and five different hydrogen bond donors (HBD; lactic acid, 1,4-butanediol, 1,2-propanediol, fructose and urea) was evaluated for the first time for the isolation of valuable bioactive compounds from Achillea millefolium L. The phytochemical profiles of NADES extracts obtained after ultrasound-assisted extraction were evaluated both spectrophotometrically (total phenolic content (TPC) and antioxidant assays) and chromatographically (UHPLC-MS and HPLC-UV). The results were compared with those obtained with 80% ethanol, 80% methanol, and water. The highest TPC value was found in the lactic acid-based NADES (ChCl-LA), which correlated with the highest antioxidant activity determined by the FRAP analysis. On the other hand, the highest antiradical potential against ABTS$^{+•}$ was determined for urea-based NADES. Phenolic acids (chlorogenic acid and dicaffeoylquinic acid isomers), flavones (luteolin and apigenin), and their corresponding glucosides were determined as the dominant individual phenolic compounds in all extracts. The antibacterial and antifungal properties of the extracts obtained against four bacterial cultures and two yeasts were evaluated using two methods: the agar dilution method to obtain the minimum inhibitory concentration (MIC) and the minimum bactericidal or fungicidal concentration (MBC or MFC), and the disc diffusion method. ChCl-LA had the lowest MIC and MBC/MFC with respect to all microorganisms, with an MIC ranging from 0.05 mg mL$^{−1}$ to 0.8 mg mL$^{−1}$, while the water extract had the weakest inhibitory activity with MIC and MBC/MFC higher than 3.2 mg mL$^{−1}$.
Keywords: viskoznost, fenoli, antioksidanti, natural deep eutectic solvents (NADES), density and viscosity, yarrow, phenolic compounds, antioxidant activity, antimicrobial activity
Published in DKUM: 09.04.2025; Views: 0; Downloads: 9
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Abstract: The objective of this study was to determine the density of anaerobic granules on different heights of a full-scale Upflow Anaerobic Sludge Bed reactor. The density was defined through the settling velocities of anaerobic granules, measured in a full-scale Upflow Anaerobic Sludge Bed reactor. In this study, granular density was calculated with the measured settling velocities and developed mathematical model. The developed mathematical model is based on the Stokes model. In the experiment, granules were taken from different heights of an Upflow Anaerobic Sludge Bed reactor, from 0.6 to 7.6 m. The granules’ diameters varied between 1 and 5 mm. The granules were taken from six different heights through the reactor. The settling velocity of the active granules (with gas in the granule pore and on the surface of the granule) was measured first. After the active granules’ settling velocity measurement, the granules were placed in a vortex to obtain degassed granules (granules without any gas in the pores or on the surface), for which the settling velocities were also measured later. It is shown that granules’ densities at different heights are independent of the reactor height.
Keywords: Upflow Anaerobic Sludge Bed reactor, microstructure, anaerobic granular sludge, settling velocity, density
Published in DKUM: 26.03.2025; Views: 0; Downloads: 12
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Abstract: The selective laser melting (SLM) process for manufacturing metals continues to be challenging in terms of achieving the maximum metallurgical properties that the process can provide. There are a variety of manufacturing parameters in the process that have individual characteristics, and when combined with other variables, the characteristics can be varied. However, in this study, the two most important manufacturing parameters, namely build direction and laser power, were considered to investigate their effects on density and tensile properties. Previously, the best scanning speed, hatch spacing, and layer thickness were determined, which directly affect the volumetric energy density in the SLM process. In this study, three different orientations and three different laser powers were selected, namely the X, Y, and Z directions and 55 W, 75 W, and 95 W laser power, respectively. Significant differences in product density were observed for the samples fabricated in the different orientations and with the different laser powers. The specimens fabricated in the Z direction always exhibit higher strength and ductility, which are significantly different from the specimens fabricated in the X and Y directions, while the laser power was 75 W and 95 W, respectively
Keywords: cobalt-chromium alloy, orientation, density, tensile strength, ductility, selective laser melting
Published in DKUM: 25.09.2024; Views: 0; Downloads: 11
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