28 research outputs found
Experimental study of radiative shocks at PALS facility
We report on the investigation of strong radiative shocks generated with the
high energy, sub-nanosecond iodine laser at PALS. These shock waves are
characterized by a developed radiative precursor and their dynamics is analyzed
over long time scales (~50 ns), approaching a quasi-stationary limit. We
present the first preliminary results on the rear side XUV spectroscopy. These
studies are relevant to the understanding of the spectroscopic signatures of
accretion shocks in Classical T Tauri Stars.Comment: 21 pages, 1 table, 7 figure
Methodological approach for farm typology construction in terms of soil health – the EU case
Soil health is a significant problem in agriculture which demands a tailor-made approach. The study aims to develop a methodological approach for farm typology construction in terms of soil health. TUdi project, under which was made this study, aims to transform unsustainable management of soils in key cropping systems in Europe and China, developing an integrated platform of alternatives to reverse soil degradation. Thus, the focus is on small, medium, and large EU farms, which produce in the three key cropping systems - grassland, cereal-based rotation, and tree crops. It was applied principal component analysis based on which it was constructed four factors, related to soil health. The results from this analysis was used to feed up the cluster analysis together with other significant variables. The developed farm typology consists of four farm types. From practical point of view was introduced a methodology which allow to determine the type of each farm according the TUdi typology
The clinical relevance of oliguria in the critically ill patient : Analysis of a large observational database
Funding Information: Marc Leone reports receiving consulting fees from Amomed and Aguettant; lecture fees from MSD, Pfizer, Octapharma, 3 M, Aspen, Orion; travel support from LFB; and grant support from PHRC IR and his institution. JLV is the Editor-in-Chief of Critical Care. The other authors declare that they have no relevant financial interests. Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Urine output is widely used as one of the criteria for the diagnosis and staging of acute renal failure, but few studies have specifically assessed the role of oliguria as a marker of acute renal failure or outcomes in general intensive care unit (ICU) patients. Using a large multinational database, we therefore evaluated the occurrence of oliguria (defined as a urine output 16 years) patients in the ICON audit who had a urine output measurement on the day of admission were included. To investigate the association between oliguria and mortality, we used a multilevel analysis. Results: Of the 8292 patients included, 2050 (24.7%) were oliguric during the first 24 h of admission. Patients with oliguria on admission who had at least one additional 24-h urine output recorded during their ICU stay (n = 1349) were divided into three groups: transient - oliguria resolved within 48 h after the admission day (n = 390 [28.9%]), prolonged - oliguria resolved > 48 h after the admission day (n = 141 [10.5%]), and permanent - oliguria persisting for the whole ICU stay or again present at the end of the ICU stay (n = 818 [60.6%]). ICU and hospital mortality rates were higher in patients with oliguria than in those without, except for patients with transient oliguria who had significantly lower mortality rates than non-oliguric patients. In multilevel analysis, the need for RRT was associated with a significantly higher risk of death (OR = 1.51 [95% CI 1.19-1.91], p = 0.001), but the presence of oliguria on admission was not (OR = 1.14 [95% CI 0.97-1.34], p = 0.103). Conclusions: Oliguria is common in ICU patients and may have a relatively benign nature if only transient. The duration of oliguria and need for RRT are associated with worse outcome.publishersversionPeer reviewe
Model predictive control for buildings with active one-pipe hydronic heating
One-pipe hydronic heating systems in their active (decentralized pumping) form promise great benefits over traditional two-pipe variable volume systems, and even more so over variable air volume systems. The heat exchanger units are connected in series, which presents its challenges and opportunities. This paper presents a model predictive controller capable of harnessing as many benefits as there is in the system when used in a building. A case study on a small office building illustrates the capabilities and validates the concept
Performance Test of the Air-Cooled Finned-Tube Supercritical CO2 Sink Heat Exchanger
This technical paper presents results of an air-cooled supercritical CO2 (sCO2) finnedtube sink heat exchanger (HX) performance test comprising wide range of variable parameters (26-166 C, 7-10 MPa, 0.1-0.32 kg/s). The measurement covered both supercritical and subcritical pressures including transition of pseudocritical region in the last stages of the sink HX. The test was performed in a newly built sCO2 experimental loop which was constructed within Sustainable Energy (SUSEN) project at Research Centre Rez (CVR). The experimental setup along with the boundary conditions are described in detail; hence, the gained data set can be used for benchmarking of system thermal hydraulic codes. Such benchmarking was performed on the open source Modelica-based code ClaRa. Both steady-state and transient thermal hydraulic analyses were performed using the simulation environment DYMOLA 2018 on a state of the art PC. The results of calculated averaged overall heat transfer coefficients (using Gnielinski correlation for sCO2 and IPPE or VDI for the air) and experimentally determined alues shows reasonably low error ofp25% and - 10%. Hence, using the correlations for the estimation of the heat transfer in the sink HX with a similar design and similar conditions gives a fair error and thus is recommended.</p
Simple Oscillator with Enlarged Tunability Range Based on ECCII and VGA Utilizing Commercially Available Analog Multiplier
This work presents an example of implementation of electronically controllable features to an originally unsuitable circuit structure of oscillator. Basic structure does not allow any electronic control and has mutually dependent condition of oscillation (CO) and frequency of oscillation (FO) if only values of passive elements are considered as the only way of control. Utilization of electronically controllable current conveyor of second generation (ECCII) brings control of CO independent of FO. Additional application of voltage amplifier with variable gain in both polarities (voltage-mode multiplier) to feedback loop allows also important enlargement of the range of the independent FO control. Moreover, our proposal was tested and confirmed experimentally with commercially available active elements (“Diamond transistor”, current-mode multiplier, voltage-mode multiplier) in working range of tens of MHz
Novel first-order all-pass filter applications of z-copy voltage differencing current conveyor
537-545The application of
z-copy voltage differencing current conveyor (ZC-VDCC) in simple and
interesting first-order all-pass sections has been studied in the present
paper. The solutions presented here have presumptions for direct electronic
control. Some of proposed circuits offer curious possibilities of control.
Electronic controllability of the VDCC allows simultaneous zero and pole
frequency adjusting, separated zero or pole frequency adjusting or migration of
zero from left half plane to right half plane of complex space. Behavioral
models of VDCC based on commercially available devices are proposed and
selected type of all-pass section was verified by simulations and also by
measurements. Results of simulations, experiments, and theoretical proposal are
compared. Experiments confirm workability of proposed behavioral equivalent
circuit in bandwidths to units of MHz
Performance Test of the Air-Cooled Finned-Tube Supercritical CO2 Sink Heat Exchanger
This technical paper presents results of an air-cooled supercritical CO2 (sCO2) finnedtube sink heat exchanger (HX) performance test comprising wide range of variable parameters (26-166 C, 7-10 MPa, 0.1-0.32 kg/s). The measurement covered both supercritical and subcritical pressures including transition of pseudocritical region in the last stages of the sink HX. The test was performed in a newly built sCO2 experimental loop which was constructed within Sustainable Energy (SUSEN) project at Research Centre Rez (CVR). The experimental setup along with the boundary conditions are described in detail; hence, the gained data set can be used for benchmarking of system thermal hydraulic codes. Such benchmarking was performed on the open source Modelica-based code ClaRa. Both steady-state and transient thermal hydraulic analyses were performed using the simulation environment DYMOLA 2018 on a state of the art PC. The results of calculated averaged overall heat transfer coefficients (using Gnielinski correlation for sCO2 and IPPE or VDI for the air) and experimentally determined alues shows reasonably low error ofp25% and - 10%. Hence, using the correlations for the estimation of the heat transfer in the sink HX with a similar design and similar conditions gives a fair error and thus is recommended.RST/Reactor Physics and Nuclear Material