PIV Investigation of the Flow Field Underneath a Generic High-Speed Train Configuration

In this paper a 2C PIV measurement of the flow field underneath a 1:50 generic high-speed train configuration (front car, 2 coaches and tail car) and a smooth generic high-speed train configuration (the same model but without bogies and the bogie cut outs and inter car gaps filled) hauled through a water towing tank at a speed of 4 m/s is presented. The 2C PIV set-up was installed so that the vertical plane (XZ) between the ground and the train, in the centre line of the train, could be measured. The PIV system that was used could measure with an acquisition rate of 10 Hz, at this frequency 6 PIV images of the instantaneous flow field with a distance of 0.4 m from each other were made per run. The total field of view was 0.065 m x 0.025 m (WxH), to cover the entire flow field underneath the train model the position had to be shifted 8 times this was realized with the help of a trigger system. At every position 10 runs were made from which the ensemble average was calculated and reconstructed with the known shift, leading to the average flow field underneath the generic high-speed train configuration. All the presented results in this paper are from the calculated ensemble aver-age. The PIV measurement technique was applicable to measure the flow field underneath a down scaled train model in a water towing tank. The generic high-speed train configuration was compared to a full scale measurement. The same structure of the flow field was found for the flow around the head and the tail of the train. The flow field was fully developed at the begin-ning of the 2nd coach for both configurations. This also agrees with the full scale measure-ment. To achieve more realistic results in the future the simplified bogies that were used should be replaced with bogies with a higher degree of details. For the comparison between the two measured configurations a clear difference was found, the generic high-speed train configuration had a higher induced velocity underneath the train due to the protruding bogie

Valorization of hydrolysis lignin from a spruce-based biorefinery by applying -valerolactone treatment

Hydrolysis lignin, i.e., the hydrolysis residue of cellulosic ethanol plants, was extracted with the green solvent γ-valerolactone (GVL). Treatments at 170–210 ◦C were performed with either non-acidified GVL/water mixtures (NA-GVL) or with mixtures containing sulfuric acid (SA-GVL). SA-GVL treatment at 210 ◦C resulted in the highest lignin solubilization (64% (w/w) of initial content), and 76% of the solubilized mass was regenerated by water induced precipitation. Regenerated lignins were characterized through compositional analysis with sulfuric acid, as well as using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), high-performance size-exclusion chromatography (HPSEC), solid-state cross-polarization/magic angle spinning 13C nuclear magnetic resonance (CP/MAS 13C NMR) spectroscopy, 1 H–13C heteronuclear single-quantum coherence NMR (HSQC NMR), and Fourier-transform infrared (FTIR) spectroscopy. The characterization revealed that the main difference between regenerated lignins was their molecular weight. Molecular weight averages increased with treatment temperature, and they were higher and had broader distribution for SA-GVL lignins than for NA-GVL lignins.publishedVersio

Radiological environmental monitoring at the ESS facility – Annual report 2021

Results from the radiological environmental monitoring of the European Spallation Source (ESS) are presented for 2021. Previous zero-point assessments (2017-2020) have mainly focussed on terrestrial samples. New sample types for 2021 include a sediment sample from a pond at the ESS and brown seaweed (Fucus) from Lomma bay and from the east coast of Scania (Skillinge). For gamma-emitting radionuclides, increased levels of anthropogenic radioactivity (177Lu and 131I) originating from hospital use, were only observed in sewage sludge samples. For tritium, the majority of the samples had activity concentrations that were below the minimum detectable activity (MDA) of 1.62 Bq l-1. Expected environmental levels, without any evidence of local contamination, were also seen in the 14C data

Exhaustion-related changes in cardiovascular and cortisol reactivity to acute psychosocial stress.

Prior findings indicate that individuals scoring high on vital exhaustion show a dysfunctional stress response (DSR), that is, reduced cortisol reactivity and habituation to psychosocial stressors. The main aim of the present study was to examine whether a DSR may be a vulnerability factor in exhaustion disorder (ED). We examined whether a DSR is present during the early stages of ED, and still is present after recovery. Three groups were studied: 1. Former ED patients (n = 14); 2. persons who during the past 6 month had experienced stress at work and had a Shirom-Melamed Burnout Questionnaire (SMBQ) score over 3.75, considered to indicate a pre-stage of ED (n = 17); 3. persons who had not experienced stress at work during the past 6 months and had a SMBQ score below 2.75 (n = 20). The participants were exposed twice to a virtual version of the Trier Social Stress Test (V-TSST), during which salivary cortisol samples were collected. In addition, high frequency heart rate variability (HF-HRV), heart rate (HR), t-wave amplitude (TWA), and alpha-amylase were assessed to examine stress reactivity and habituation in the autonomic nervous system (ANS). The initial analyses showed dear hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) activations in both V-TSST sessions, together with habituation of cortisol and heart rate in the second session, but without any significant group differences. However, the former ED patients showed considerable variation in self-reported signs of exhaustion (SMBQ). This led us to assign former ED patients with lower ratings into the low SMBQ group (LOWS) and those with higher ratings to the high SMBQ group (HIGHS). When repeating the analyses a different picture emerged; the HIGHS showed a lower cortisol response to the V-TSST than did the LOWS. Both groups' cortisol response habituated to the second V-TSST session. The ANS responses did not differ between the two groups. Thus, persons in a pre-stage of ED and unrecovered former ED patients showed signs of DSR, in contrast to healthy controls and recovered former ED patients. The results may be interpreted as indicating that DSR in the HPA axis is present early on in the stress process, but subsides after successful recovery. (C) 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)